Kuala Selangor, Malaysia
Kuala Selangor, Malaysia

Universiti Putra Malaysia , or UPM, is recognised by the independent government assessments as one of Malaysia's leading research Universities. Founded in 1931 as the School of Agriculture, the University today combines impressive modern facilities and a dynamic approach to teaching and research with its proud heritage of quality services and achievements. UPM main campus located in central Peninsular Malaysia, close to the capital city, Kuala Lumpur and next to Malaysia’s administrative capital city, Putrajaya. It was formerly known as Universiti Pertanian Malaysia or Agricultural University of Malaysia. UPM is a research university offering undergraduate and postgraduate courses with a research focus on agricultural science and its related fields. It was ranked as the joint 376th best university in the world in 2014 by Quacquarelli Symonds. Wikipedia.

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University Putra Malaysia | Date: 2016-03-23

The present invention provides a method for the isolation of nucleic acid from microbial cells in an environmental sample. The method includes preparing a suspension of the environmental sample, lysing the suspended sample with a buffered solution, adding sodium dodecylsulfate solution to the lysed suspended sample, carrying out solvent extraction and separation to obtain an aqueous phase, reacting the aqueous phase with solvents to generate an insoluble precipitate containing nucleic acid, and isolating the nucleic acid therefrom, thereby releasing high molecular weight nucleic acid pellets from the cells.

Beng Hoong Y.,University Putra Malaysia | Pizzi A.,University of Lorraine | Md. Tahir P.,University Putra Malaysia | Pasch H.,Stellenbosch University
European Polymer Journal | Year: 2010

The MALDI-TOF mass spectrometry (MS) and solid state CP-MAS 13C Nuclear Magnetic Resonance (NMR) spectroscopic technique were introduced to characterize Acacia mangium tannin (condensed tannins). The MALDI-TOF MS illustrated a series of peaks corresponding to oligomers of condensed tannins of up to 11 flavonoid units (3200 Da). A. mangium condensed tannins were found to consist predominantly of prorobinetinidin combined with profisetinidin and prodelphinidin. Both the MALDI-TOF mass spectra and the solid state CP-MAS 13C NMR indicated that the A. mangium tannins obtained from Kudat, had an almost completely linear structure; In addition, Lembah Beringin, consist of ''angular" polymer structure; and Tawau, has included ''twice-angular" polymer structures present in oligomers type of up to 7 flavonoid units. The high degree of polymerization of linear, angular type, twice-angular structures and longer oligomer (3200 Da) chains have not been observed in previous studies of condensed tannins. The spectra also indicated that A. mangium tannins are more heavily branched and have higher degree of polymerization (<7.0) compared to commercial mimosa (A. mearnsii) tannin (4.9). Because tannins are phenolic, it was expected that they can be used to replace phenol-formaldehyde (PF) adhesives. © 2010 Elsevier Ltd. All rights reserved.

Imteaz M.A.,Swinburne University of Technology | Ahsan A.,University Putra Malaysia | Shanableh A.,University of Sharjah
Resources, Conservation and Recycling | Year: 2013

A daily water balance model is used for the performance analysis and design optimisation of rainwater tanks at four different regions of Melbourne; North, Central, South-East and South-West. These four different regions of Melbourne are characterised by notable different topography and rainfall characteristics. From historical rainfall data, three representative years (dry, average and wet) are selected. Reliability is defined as percentage of days in a year when rainwater tank is able to supply the intended partial demand for a particular condition. For the three climatic conditions, a number of reliability charts are produced for domestic rainwater tanks in relation to tank volume, roof area and number of people in a house (i.e. water demand). It is found that for a relatively small roof size (100 m2), 100% reliability cannot be achieved even with a very large tank (10,000 L). Reliability becomes independent of tank size for tank sizes larger than 4000-7000 L depending on the location. This is defined as threshold tank size, relationships with threshold tank sizes and annual rainfall amounts are then established for all the locations. A new factor named 'Rainwater Accumulation Potential (RAP)' has been introduced and maximum achievable reliabilities for different reasonable RAPs under different climatic conditions are presented for all the locations selected in this study. From these findings, for the design of rainwater tank size it is recommended to have a RAP value of 0.8-0.9 for greater Melbourne. © 2013 Elsevier B.V. All rights reserved.

Kaboli P.J.,University Putra Malaysia | Rahmat A.,University Putra Malaysia | Ismail P.,University Putra Malaysia | Ling K.-H.,University Putra Malaysia
Pharmacological Research | Year: 2015

MicroRNAs (miRNA) are 21-23 nucleotide molecules not translated into proteins that bind and target the 3′ untranslated regions of mRNA. These characteristics make them a possible tool for inhibiting protein translation. Different cellular pathways involved in cancer development, such as cellular proliferation, apoptosis, and migration, are regulated by miRNAs. The objective of this review is to discuss various miRNAs involved in breast cancer in detail as well as different therapeutic strategies from the clinic to industry. A comprehensive discussion is provided on various miRNAs involved in breast cancer development, progression, and metastasis as well as the roles, targets, and related therapeutic strategies of different miRNAs associated with breast cancer. miRNAs known to be clinically useful for the diagnosis and prognosis of breast cancer are also discussed. Different strategies and challenges, including nucleic acid-based (miRNA mimics, antagomiRs, and miRNA sponges) and drug-based (drug resistance, drugs/miRNA interaction, nanodelivery, and sensing systems) approaches to suppress specific oncogenes and/or activate target tumor suppressors are discussed. In contrast to other articles written on the same topic, this review focuses on the therapeutic and clinical value of miRNAs as well as their corresponding targets in order to explore how these strategies can overcome breast cancer, which is the second most frequent type of cancer worldwide. This review focuses on promising and validated miRNAs involved in breast cancer. In particular, two miRNAs, miR-21 and miR-34, are discussed as the most promising targets for RNA-based therapy in non-invasive and invasive breast cancer, respectively. Finally, relevant and commercialized therapeutic strategies are highlighted. © 2015 Elsevier Ltd.All rights reserved.

Karimi-Googhari S.H.,Shahid Bahonar University of Kerman | Lee T.S.,University Putra Malaysia
International Journal of Soft Computing | Year: 2011

Accurate prediction of reservoir inflows is crucial for optimizing the operations of managing water resources. With emerging new data driven modeling approaches, methods based on neuro-fuzzy are becoming established in academic and practical applications. This study investigates the ability of Adaptive Neuro-Fuzzy Inference System (ANFIS) method to improve the accuracy of daily reservoir inflow forecasting. The subtractive clustering method is used to find the best number of fuzzy rules. A comparison is made between the ANFIS model and the Artificial Neural Network (ANN) model. A wide range of statistics measures are used to evaluate the performance of the models. Based on comparisons, it was revealed that the ANFIS technique could not improve the accuracy of estimations in a small tropical catchment and the ANN performed better, especially in capturing peak inflows. © Medwell Journals, 2011.

Ahsan A.,University Putra Malaysia | Imteaz M.,Swinburne University of Technology | Rahman A.,University of Western Sydney | Yusuf B.,University Putra Malaysia | Fukuhara T.,University of Fukui
Desalination | Year: 2012

In this paper, a detail comparison of the design, fabrication, cost and water production analysis between an old Tubular Solar Still (TSS) and improved (new) one is presented. Since the cover material, a vinyl chloride sheet, of the old TSS was a little bit heavy, expensive and cannot be formed into a desirable size easily, a highly durable polythene film was adopted as the cover of the new TSS. The new TSS is made of cheap and locally acquisitioned lightweight materials. Consequently, the weight and cost of the new TSS were noticeably reduced and the durability was distinctly increased. A few field experiments on the new TSS were carried out in Fukui (Japan) and Muscat (Oman) and the observed results are compared with the old one. The water production flux is proportional to the temperature difference inside the still. Evaporation mass transfer coefficients (MTCs) and heat transfer coefficients (HTCs) are higher than those of condensation. Convection HTCs are much lower than those of evaporation/condensation. Finally, a linear relation is newly found between the total HTCs and MTCs. © 2012 Elsevier B.V..

Moeini H.,University Putra Malaysia | Omar A.R.,University Putra Malaysia | Shafee N.,University Putra Malaysia | Yusoff K.,University Putra Malaysia
Applied Microbiology and Biotechnology | Year: 2011

The AcmA binding domains of Lactococcus lactis were used to display the VP1 protein of chicken anemia virus (CAV) on Lactobacillus acidophilus. One and two repeats of the cell wall binding domain of acmA gene were amplified from L. lactis MG1363 genome and then inserted into co-expression vector, pBudCE4.1. The VP1 gene of CAV was then fused to the acmA sequences and the VP2 gene was cloned into the second MCS of the same vector before transformation into Escherichia coli. The expressed recombinant proteins were purified using a His-tag affinity column and mixed with a culture of L. acidophilus. Whole cell ELISA and immunofluorescence assay showed the binding of the recombinant VP1 protein on the surface of the bacterial cells. The lactobacilli cells carrying the CAV VP1 protein were used to immunize specific pathogen-free chickens through the oral route. A moderate level of neutralizing antibody to CAV was detected in the serum of the immunized chickens. A VP1-specific proliferative response was observed in splenocytes of the chickens after oral immunization. The vaccinated groups also showed increased levels of Th1 cytokines interleukin (IL)-2, IL-12, and IFN-γ. These observations suggest that L. acidophilus can be used in the delivery of vaccines to chickens. © 2010 Springer-Verlag.

Mohamad Haafiz M.K.,University of Technology Malaysia | Mohamad Haafiz M.K.,Universiti Sains Malaysia | Hassan A.,University of Technology Malaysia | Jawaid M.,University Putra Malaysia
Carbohydrate Polymers | Year: 2013

In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed. © 2013 Elsevier Ltd.

Arunkumar T.,NGP | Denkenberger D.,Denkenberger Inventing and Consulting | Ahsan A.,University Putra Malaysia
Desalination | Year: 2013

In order to augment the efficiency and distillate yield in the concentrator-coupled hemispherical basin solar still, a phase change material (PCM) was added. Two modes of operation have been studied experimentally, (1) single-slope solar still without the PCM effect, and (2) single-slope solar still with the PCM effect. The temperature of water (Tw), temperature of PCM (TPCM), air temperature (Tair), inner cover temperature (Tic) and outer cover temperature (Toc) were measured. Experimental results indicate that the effect of thermal storage in the concentrator-coupled hemispherical basin solar still increases the productivity by 26%. It was concluded that the productivity greatly increased due to the still integrated with PCM. © 2013 Elsevier B.V. All rights reserved.

Imteaz M.A.,Swinburne University of Technology | Rahman A.,University of Western Sydney | Ahsan A.,University Putra Malaysia
Resources, Conservation and Recycling | Year: 2012

A spreadsheet based daily water balance model is used for the performance analysis and design optimisation of rainwater tanks at two different regions of Melbourne, South-East and Central Melbourne. These two different regions of Melbourne are characterised by notable different topography and rainfall characteristics. From historical rainfall data, three representative years (dry, average and wet) are selected. Reliability is defined as percentage of days in a year when rainwater tank is able to supply the intended partial demand for a particular condition. For the three climatic conditions, a number of reliability charts are produced for domestic rainwater tanks in relations to tank volume, roof area, number of people in a house (i.e. water demand) and percentage of total water demand to be satisfied by the harvested rainwater. It is found that for a relatively small roof size (100 m 2), 100% reliability cannot be achieved even with a very large tank (10,000 L). Reliability becomes independent of tank size for tank sizes larger than 5000-7000 L depending on the location. This is defined as threshold tank size, relationships with threshold tank sizes and annual rainfall amounts are then established for both the locations. It is found that for a particular annual rainfall amount, threshold tank size for South-East Melbourne is higher than that of Central Melbourne. However, for a relatively large roof size (200 m 2), approximately 90% reliability can be achieved with a tank size of 10,000 L and with further increase in tank size, a 100% reliability is achievable, except in a dry year. Furthermore, it is found that reliabilities for South-East Melbourne maintain consistent higher values as compared to Central Melbourne. © 2012 Elsevier B.V.

Wijnker E.,Wageningen University | Van Dun K.,Rijk Zwaan R and D Fijnaart | De Snoo C.B.,Rijk Zwaan R and D Fijnaart | Lelivelt C.L.C.,Rijk Zwaan R and D Fijnaart | And 7 more authors.
Nature Genetics | Year: 2012

Traditionally, hybrid seeds are produced by crossing selected inbred lines. Here we provide a proof of concept for reverse breeding, a new approach that simplifies meiosis such that homozygous parental lines can be generated from a vigorous hybrid individual. We silenced DMC1, which encodes the meiotic recombination protein DISRUPTED MEIOTIC cDNA1, in hybrids of A. thaliana, so that non-recombined parental chromosomes segregate during meiosis. We then converted the resulting gametes into adult haploid plants, and subsequently into homozygous diploids, so that each contained half the genome of the original hybrid. From 36 homozygous lines, we selected 3 (out of 6) complementing parental pairs that allowed us to recreate the original hybrid by intercrossing. In addition, this approach resulted in a complete set of chromosome- substitution lines. Our method allows the selection of a single choice offspring from a segregating population and preservation of its heterozygous genotype by generating homozygous founder lines. © 2012 Nature America, Inc. All rights reserved.

Ahsan A.,University Putra Malaysia | Imteaz M.,Swinburne University of Technology | Thomas U.A.,University Putra Malaysia | Azmi M.,University Putra Malaysia | And 2 more authors.
Applied Energy | Year: 2014

This study aims at developing a low cost technique to be used in rural and coastal areas for converting saline water into potable water using solar energy. A triangular solar still (TrSS) was, therefore, designed and developed with cheap, lightweight, local and available materials. A number of field experiments were carried out to evaluate the effects of solar radiation intensity, ambient air temperature and the initial water depth on the daily water production of the TrSS. A time lag of about and hour between the hourly peaks of solar radiation and water production is observed. Finally, a few essential relationships were attained, e.g. between the daily production and the initial water depth, between the daily production and daily solar radiation, and between the daily production and the average ambient temperature. The effect of the initial water depth in the basin on the daily water productivity was evaluated by varying the water depths (1.5, 2.5 and 5. cm) with the climatic condition of Malaysia and an inverse proportional relationship was revealed between them. However, the daily water productivity is nearly proportional to the daily solar radiation. In addition, some important water quality parameters were tested in the laboratory to evaluate the distillate quality and were then compared with the drinking water standards. © 2013 Elsevier Ltd.

Tey Y.S.,University of Adelaide | Tey Y.S.,University Putra Malaysia | Brindal M.,University of Adelaide
Precision Agriculture | Year: 2012

Increasing pressure for food security and sustainability as well as a need to halt environmental degradation has focused attention on increasing the efficient use of farm resources. One answer to aspects of that problem is the use of precision agricultural technologies (PATs). To facilitate their adoption, initiatives have been fostered in developed countries since the 1980s. Despite a low rate of adoption elsewhere, similar efforts in recent years have been initiated in developing countries. Given this, understanding those underlying factors that influence the adoption of PATs is vital. It is timely to review these factors and to draw policy implications from that review for future actions. This review, based on studies investigating the limited adoption of PATs in 'experienced' countries, extrapolates their findings to explain why farmers have or have not adopted PATs. At the same time, this review summarizes the key insights for more effectively targeting 'new' followers: e. g. it provides some answers to the question of who is more likely to adopt PATs. Additionally, the review points to the limitations of current research in the area and suggests a robust economic model or multidisciplinary approach be adopted for future investigation. © 2012 Springer Science+Business Media, LLC.

Lei G.K.P.,University of Swansea | Lim L.T.,University Putra Malaysia | Marhic M.E.,University of Swansea
Optics Communications | Year: 2013

A continuous-wave fiber optical parametric oscillator with a ring cavity containing a highly nonlinear fiber and two cascaded narrowband filters is demonstrated. We report a 3-dB laser linewidth of less than 400 kHz at 1549 nm with single longitudinal mode operation. Wavelength stability of the laser is <±100 MHz, governed mainly by the narrowband filters. © 2013 Elsevier B.V. All rights reserved.

Althuwaynee O.F.,University Putra Malaysia | Pradhan B.,University Putra Malaysia | Lee S.,Korea Institute of Geoscience and Mineral Resources
Computers and Geosciences | Year: 2012

The objective of this paper is to exploit the potential application of an evidential belief function model to landslide susceptibility mapping at Kuala Lumpur city and surrounding areas using geographic information system (GIS). At first, a landslide inventory map was prepared using aerial photographs, high resolution satellite images and field survey. A total 220 landslides were mapped and an inventory map was prepared. Then the landslide inventory was randomly split into a testing dataset 70% (153 landslides) and remaining 30% (67 landslides) data was used for validation purpose. Fourteen landslide conditioning factors such as slope, aspect, curvature, altitude, surface roughness, lithology, distance from faults, ndvi (normalized difference vegetation index), land cover, distance from drainage, distance from road, spi (stream power index), soil type, precipitation, were used as thematic layers in the analysis. The Dempster-Shafer theory of evidence model was applied to prepare the landslide susceptibility maps. The validation of the resultant susceptibility maps were performed using receiver operating characteristics (ROC) and area under the curve (AUC). The validation results show that the area under the curve for the evidential belief function (the belief map) model is 0.82 (82%) with prediction accuracy 0.75 (75%). The results of this study indicated that the EBF model can be effectively used in preparation of landslide susceptibility maps. © 2012 Elsevier Ltd.

Achenef M.B.,University of Gondar | Arifah A.K.,University Putra Malaysia
Academic Journal of Cancer Research | Year: 2012

Conjugated linoleic acids (CLAs) comprised of geometrical and positional isomers of octadecadienoic (18:2) acid with conjugated double bond system. They are found naturally in ruminant food products such as meat and milk because of the process of bacterial biohydrogenation and hydrolysis in the rumen. Studies have shown that CLAs have many health promoting properties. This study was conducted to assess and compare the cytotoxic effects, induction of apoptosis and cell cycle arrest by CLA isomers on human breast cancer cells (MCF7). Cells were grown on RPMI 1640 media and treated with different concentrations of cis-9, trans-11 (c9, t11), trans-10, cis-12 (t10, c12) and mixed isomers of CLA for 72 hours. The results were determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) cytotoxicity assay and terminal deoxynucleotide transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. The viability of MCF7 cancer cells was reduced significantly (P<0.05) by all CLA isomers used in a dose-dependent manner. The median inhibitory concentration (IC50) value varies with type of CLA isomer. t10, c12 was significantly 50 (P<0.05) more potent than c9, t11 CLA isomer. All CLA isomers induced significantly (P<0.05) higher proportion of apoptotic cells. It was also observed that significantly (P<0.05) higher proportion of cells in G0/1 but lower proportion in S and G2/M phases of the cell cycle in treated cells. These results suggested that CLA isomers 2 reduce the viability of MCF7 cancer cells which is associated with cell cycle arrest and induction of apoptosis. © IDOSI Publications, 2012.

Elizabeth G.,University Putra Malaysia | Ann M.T.J.A.,University of Sfax
Medical Journal of Malaysia | Year: 2010

The haemoglobinopathies and thalassemias represent the most common inherited monogenic disorders in the world1. Beta-thalassaemia major is an ongoing public health problem in Malaysia2. Prior to 2004, the country had no national policy for screening and registry for thalassemia. In the absence of a national audit, the true figure of the extent of thalassemia in the Malaysian population was largely presumptive from micro-mapping studies from various research workers in the country. The estimated carrier rate for beta-thalassemia in Malaysia is 3.5-4%. There were 4768 transfusion dependent thalassemia major patients as of May 2010 (Data from National Thalassemia Registry).

Imteaz M.A.,Swinburne University of Technology | Ahsan A.,University Putra Malaysia | Rahman A.,University of Western Sydney | Mekanik F.,Swinburne University of Technology
Resources, Conservation and Recycling | Year: 2013

Urban/rural stormwater quantity modelling has been well-researched and has achieved sufficient accuracy benchmark. However, modelling stormwater runoff quality (i.e. pollutants transport associated with stormwater) are relatively difficult and largely depends on catchment characteristics/land-uses; these can be estimated with acceptable accuracy provided pollutants transport equations are established through extensive field measurements. To ensure ecologically sustainable development, several stormwater treatment systems have been proposed. Model of Urban Stormwater Improvement Conceptualisation (MUSIC) developed and widely used in Australia, estimates pollutant transport from catchments and stormwater treatment through different systems. This paper presents a study on the accuracy of MUSIC estimations for different stormwater treatment options used in Australia and abroad. Data on several field measurements on different constructed stormwater treatment systems (bioretention, grass swale and porus pavement) in Australia, Sweden, New Zealand and Scotland was collected from literatures. The experimental results were compared with MUSIC's estimations under similar conditions. In general, it has been found that MUSIC can simulate flow conditions with good accuracy, however MUSIC's predictions on the removal efficiencies of Total Suspended Solids (TSS), Total Phosphorus (TP) and Total Nitrogen (TN) are varying. Potential reasons for these discrepancies are discussed. Also, a summary table showing MUSIC's overall capability on simulating stormwater treatment efficiencies for different treatment measures has been presented. © 2012 Elsevier B.V.

Shahmohammadi M.S.,University Putra Malaysia | Keyhanian S.,University of Groningen
Applied Energy | Year: 2015

Malaysia has abundant potentials of renewable energy resources mainly because of its rich agriculture that makes high potential in bio-power and its tropical climate, which provides sufficient sunlight for utilization of solar systems. Feed in Tariff mechanism has been applied since 2011 in Malaysia to expand utilization of renewable energy for electricity generation. In this study, a broad range of data is gathered to develop a comprehensive system dynamics model to evaluate the impacts of Feed in Tariff mechanism on the generation mix of Malaysia during a 20-year period between 2011 and 2030. Results demonstrate that although the policy may lead to a satisfactory level of target achievement but the Malaysian government may face an increasing shortage in its RE fund budget starting around 2019 unless it increases its income sources by rising the surcharges on electricity bills or decreases its expenditures by optimizing the amount of FiT payments in different periods. The sensitivity analysis illustrates that the more funding will not lead to a more sustainable generation mix unless it is paid in the right time and in the right direction. Using this model, policymakers can carry out analysis to determine the amount of money that must be collected from the electricity consumers through the surcharges on electricity bills as well as the amount of feed in tariff to be paid for different renewable resources in different periods. © 2015 Elsevier Ltd.

Shariat A.,University Putra Malaysia | Kargarfard M.,University of Isfahan | Danaee M.,Islamic Azad University at Roudehen | Tamrin S.B.M.,University Putra Malaysia
Journal of Strength and Conditioning Research | Year: 2015

Shariat, A, Kargarfard, M, Danaee, M, and Bahri Mohd Tamrin, S. Intensive resistance exercise and circadian salivary testosterone concentrations among young male recreational lifters. J Strength Cond Res 29(1): 151-158, 2015-Strength and morphological adaptations to resistance exercise are mediated in part by anabolic hormones such as testosterone, yet the time course of variability in circadian hormone concentrations is not well characterized. This study, investigated how the circadian rhythm of salivary testosterone is altered by resistance exercise in young men. Twenty healthy young male recreational lifters (age, 18.0 ± 1.3 years) with 2 years of experience in weightlifting were recruited. A randomized controlled trial was conducted, and subjects were randomly assigned to either the resistance exercise group (n = 10), who completed a series of resistance exercise (3 times a week, in the afternoon, 6-7 repetitions, at 85% of 1 repetition maximum for 3 weeks), or a control group (n = 10), who did not exercise during the 3 weeks. Before and after the study, an unstimulated saliva sample (2 ml) was taken every 2 hours for a maximum of 16 hours during each day. A significant decrease was observed in the resistance exercise (44.2%, p = 0.001) and control group (46.1%, p = 0.001) for salivary testosterone at each time point compared with baseline (p = 0.001). There was also no significant difference between the exercise and resting conditions in both groups for salivary testosterone (p . 0.05), except a significantly higher increase by 38.4% vs. 20.02% (p = 0.001), at 1730 hours during exercise sessions in the resistance exercise group compared with the control group. Resistance exercise has no noteworthy effect on circadian secretion of salivary testosterone throughout the 16 waking hours. These results indicate that athletes can undertake resistance exercise in either the morning or afternoon with the knowledge that a similar testosterone response can be expected regardless of the time of day. © 2015 National Strength and Conditioning Association.

Oh H.-J.,Korea Institute of Geoscience and Mineral Resources | Pradhan B.,Sudan University of Science and Technology | Pradhan B.,University Putra Malaysia
Computers and Geosciences | Year: 2011

This paper presents landslide-susceptibility mapping using an adaptive neuro-fuzzy inference system (ANFIS) using a geographic information system (GIS) environment. In the first stage, landslide locations from the study area were identified by interpreting aerial photographs and supported by an extensive field survey. In the second stage, landslide-related conditioning factors such as altitude, slope angle, plan curvature, distance to drainage, distance to road, soil texture and stream power index (SPI) were extracted from the topographic and soil maps. Then, landslide-susceptible areas were analyzed by the ANFIS approach and mapped using landslide-conditioning factors. In particular, various membership functions (MFs) were applied for the landslide-susceptibility mapping and their results were compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curve for all landslide susceptibility maps were drawn and the areas under curve values were calculated. The ROC curve technique is based on the plotting of model sensitivity - true positive fraction values calculated for different threshold values, versus model specificity - true negative fraction values, on a graph. Landslide test locations that were not used during the ANFIS modeling purpose were used to validate the landslide susceptibility maps. The validation results revealed that the susceptibility maps constructed by the ANFIS predictive models using triangular, trapezoidal, generalized bell and polynomial MFs produced reasonable results (84.39%), which can be used for preliminary land-use planning. Finally, the authors concluded that ANFIS is a very useful and an effective tool in regional landslide susceptibility assessment. © 2011 Elsevier Ltd.

Nur Hanani Z.A.,University Putra Malaysia | Roos Y.H.,University College Cork | Kerry J.P.,University College Cork
International Journal of Biological Macromolecules | Year: 2014

The manufacture and potential application of biodegradable films for food application has gained increased interest as alternatives to conventional food packaging polymers due to the sustainable nature associated with their availability, broad and abundant source range, compostability, environmentally-friendly image, compatibility with foodstuffs and food application, etc. Gelatin is one such material and is a unique and popularly used hydrocolloid by the food industry today due to its inherent characteristics, thereby potentially offering a wide range of further and unique industrial applications. Gelatin from different sources have different physical and chemical properties as they contain different amino acid contents which are responsible for the varying characteristics observed upon utilization in food systems and when being utilized more specifically, in the manufacture of films. Packaging films can be successfully produced from all gelatin sources and the behaviour and characteristics of gelatin-based films can be altered through the incorporation of other food ingredients to produce composite films possessing enhanced physical and mechanical properties. This review will present the current situation with respect to gelatin usage as a packaging source material and the challenges that remain in order to move the manufacture of gelatin-based films nearer to commercial reality. © 2014 Elsevier B.V.

Esa N.M.,University Putra Malaysia
Asian Pacific Journal of Cancer Prevention | Year: 2014

Colorectal cancer (CRC) is the third most common malignancy and fourth most common cause of cancer mortality worldwide. Untreated chronic inflammation in the intestine ranks among the top three high-risk conditions for colitis-associated colorectal cancer (CAC). Signal Transducer and Activator of Transcription 3 (STAT3) protein is a member of the STAT family of transcription factors often deregulated in CRC. In this review, we try to emphasize the critical role of STAT3 in CAC as well as the crosstalk of STAT3 with inflammatory cytokines, nuclear factor (NF)-κB, PI3K/Akt, Mammalian Target of Rapamycin (mTOR), Notch, Wnt/β-catenin and microRNA (MiR) pathways. STAT3 is considered as a primary drug target to treat CAC in humans and rodents. Also we updated the findings for inhibitors of STAT3 with regard to effeects on tumorigenesis. This review will hopefully provide insights on the use of STAT3 as a therapeutic target in CAC.

Ahsan A.,University Putra Malaysia | Denkenberger D.,Denkenberger Inventing and Consulting | Okundamiya M.S.,Ambrose Alli University
Applied Energy | Year: 2013

This work reports an innovative design of tubular solar still with a rectangular basin for water desalination with flowing water and air over the cover. The daily distillate output of the system is increased by lowering the temperature of water flowing over it (top cover cooling arrangement). The fresh water production performance of this new still is observed in Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore (11° North, 77° East), India. The water production rate with no cooling flow was 2050. ml/day (410. ml/trough). However, with cooling air flow, production increased to 3050. ml/day, and with cooling water flow, it further increased to 5000. ml/day. Despite the increased cost of the water cooling system, the increased output resulted in the cost of distilled water being cut in roughly half. Diurnal variations of a few important parameters are observed during field experiments such as water temperature, cover temperature, air temperature, ambient temperature and distillate output. © 2012 Elsevier Ltd.

Imteaz M.A.,Swinburne University of Technology | Shanableh A.,University of Sharjah | Rahman A.,University of Western Sydney | Ahsan A.,University Putra Malaysia
Resources, Conservation and Recycling | Year: 2011

Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185 m3 and 110 m3) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15-21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits. © 2011 Elsevier B.V. All rights reserved.

Imteaz M.A.,Swinburne University of Technology | Ahsan A.,University Putra Malaysia | Naser J.,Swinburne University of Technology | Rahman A.,University of Western Sydney
Resources, Conservation and Recycling | Year: 2011

With the aim of developing a comprehensive decision support tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model was developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and rainwater demand. In order to assess reliability of domestic rainwater tanks in augmenting partial household water demand in Melbourne (Australia) area, the developed water balance model was used for three different climatic conditions (i.e. dry, average, and wet years). Historical daily rainfall data was collected from a rainfall station near Melbourne city central. From historical rainfall data three representative years (driest, average and wettest) were selected for the current analysis. Reliability is defined as percentage of days in a year when rainwater tank was able to supply the intended partial demand for a particular condition. For the three climatic conditions, several reliability charts are presented for domestic rainwater tanks in relations to tank volume, roof area, number of people in a house (i.e. water demand) and percentage of total water demand to be satisfied by harvested rainwater. In brief, for a two-people household scenario, ∼100% reliability can be achieved with a roof size of 150-300 m2 having a tank size of 5000-10,000 L. However, for a four-people household scenario, it is not possible to achieve a 100% reliability, even with a roof size of 300 m2 and a tank size of 10,000 L. © 2011 Elsevier B.V.

Tan Y.H.,University Malaysia Sarawak | Abdullah M.O.,University Malaysia Sarawak | Taufiq-Yap Y.H.,University Putra Malaysia
Applied Energy | Year: 2015

The primary goal of this paper is to investigate the catalyst characterization and biodiesel yield of a biodiesel converted from a used cooking oil source via heterogeneous catalysts derived from very rare type of eggshell: ostrich-eggshell (ostrich-eggshell derived CaO). It also aims to compare the performance of CaO catalyst derived from both waste ostrich-eggshell and the conventional chicken-eggshell, and to find the optimum conditions for biodiesel production. The prepared catalysts were then characterized by using XRD, FT-IR, BET, SEM, TGA and CO2-TPD. The parametric effects on the biodiesel production, such as catalyst concentration, molar ratio of methanol to oil, reaction temperature, reaction time, speed and reusability of the catalyst were investigated. The experimental result showed that 1.5wt.% catalyst, 12:1M ratio of methanol to oil, 65°C reaction temperature, 2h reaction time with speed of 250rpm gave the best results. It was found that the ostrich-eggshell derived CaO catalyst shows higher surface area, higher basicity and smaller particle size. The maximum biodiesel yield is 96% and 94% for calcined ostrich-eggshell and chicken-eggshell, respectively. The CaO catalyst derived from waste calcined ostrich and chicken-eggshell maintained a good catalytic activity even after being repeatedly used for 5 cycles with yield around 70%, which implies potential saving and affordable biodiesel production possibilities. © 2015 Elsevier Ltd.

Saadatian O.,National University of Malaysia | Sopian K.,National University of Malaysia | Salleh E.,National University of Malaysia | Lim C.H.,National University of Malaysia | And 4 more authors.
Renewable and Sustainable Energy Reviews | Year: 2013

Global warming, depletion of natural resources, acid rains, air and water pollutions, and ozone depletions are some of the environmental consequences that are deemed attributable to human activities on planet earth. Sustainable practices have been therefore evolved as main remedies to tackles these issues. Green roof strategy is one of these practices that not only provides heat island amelioration and thermal comfort for occupants but also reduces energy consumption of buildings as well as add aesthetic values to the environment. This paper targets to run a review on the application of green roof strategy. The review scans a time frame from 2002 through early 2012 with a focus on energy related topics on energy related topics of green roofs. The review discussed various types of green roofs, components of a green roof, economic revenues, and technical attributes. Many general advantages and few general disadvantages of green roofs in one hand and pros and cons of green roofs with respect to energy utilization on the other hand are also synthesized. Some recommendations for future study are also proposed. © 2013 Elsevier Ltd.

Shari Z.,University Putra Malaysia | Soebarto V.,University of Adelaide
Construction Innovation | Year: 2014

Purpose - Economically, Malaysia has one of the fastest growing construction industries in the world; however, the necessary balance between socio-economic and ecological systems - to avoid further environmental damage - has not yet been reached by the industry. This paper aims to explore the extent of sustainable development practices (socially, environmentally and economically) in the Malaysian construction industry, focusing on the office building sector. Design/methodology/approach - Semi-structured in-depth interviews with 30 stakeholders from various backgrounds of the Malaysian construction industry are used to explore their challenges and motivations for pursuing sustainable outcomes. Findings - The study finds that economic issues are the first priorities among stakeholders in any decision-makings for building projects and cost becomes one of the major reasons for the slow progress in implementing sustainable practices in building projects. Socially, there is still a wide gap of knowledge and awareness on sustainability issues among stakeholders, explaining the lack of commitment in achieving sustainability. Research limitations/implications - The sample size is only adequate to enable internal generalisation; hence, further research is required to test the generalisability of the findings in this research. Practical implications - This paper informs the government and regulatory stakeholders, research and education sector, private sector, and clients of the building industry, where the authors currently are and the gaps that the authors have to bridge in order to make sustainability more socially acceptable and integral in the local construction industry. Originality/value - There have been very limited studies on exploring the views from various groups of stakeholders regarding all the three components of sustainable development in the Malaysian construction industry. Copyright © 2014 Emerald Group Publishing Limited. All rights reserved.

Hamid T.A.,University Putra Malaysia | Krishnaswamy S.,University of Adelaide | Abdullah S.S.,University Putra Malaysia | Momtaz Y.A.,University Putra Malaysia
Dementia and Geriatric Cognitive Disorders | Year: 2010

Objective: The rapid expansion of the aged population in Malaysia is expected to greatly increase the number of persons with dementia in the country. However, data on dementia prevalence at the national level is lacking, and little is known about the sociodemographic risk factors and correlates of dementia. This paper describes a nationwide study of dementia prevalence and its sociodemographic risk factors and health correlates among older Malaysians. Methods: In the nationwide study, the Mental Health and Quality of Life of Older Malaysians, AGECAT-GMS was used to diagnose dementia in a nationally representative sample of 2,980 persons aged 60 and above. Results: The prevalence rate of dementia was 14.3%. Higher dementia prevalences were found in oldest age (26.3%), women (19.7%), no formal education (24.1%), Bumiputeras (32.2%), unmarried (19.4%), unemployed (31.3%) and very poor on self-rated health (33.3%). Multivariate logistic regression analyses showed that older age, female gender, no formal education, ethnicity and very poor self-rated health were independent risk factors and correlates of dementia. Conclusions: Relatively higher prevalence rates of dementia in older Malaysians were accounted for by greater proportions without education, Malay and Bumiputera ethnicity, and other unknown factors which should be further investigated. Copyright © 2011 S. Karger AG, Basel.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: EINFRA-1-2014 | Award Amount: 8.65M | Year: 2015

Over the last decade, the European Grid Infrastructure (EGI) has built a distributed computing and data infrastructure to support over 21,000 researchers from many disciplines with unprecedented data analysis capabilities. EGI builds on the European and national investments and relies on the expertise of EGI.eu - a not-for-profit foundation that provides coordination to the EGI Community, including user groups, EGI.eu participants in the EGI Council, and the other collaborating partners. The mission of EGI-Engage is to accelerate the implementation of the Open Science Commons vision, where researchers from all disciplines have easy and open access to the innovative digital services, data, knowledge and expertise they need for their work. The Open Science Commons is grounded on three pillars: the e-Infrastructure Commons, an ecosystem of key services; the Open Data Commons, where any researcher can access, use and reuse data; and the Knowledge Commons, in which communities have shared ownership of knowledge and participate in the co-development of software and are technically supported to exploit state-of-the-art digital services. EGI-Engage will expand the capabilities offered to scientists (e.g. improved cloud or data services) and the spectrum of its user base by engaging with large Research Infrastructures (RIs), the long-tail of science and industry/SMEs. The main engagement instrument will be a network of eight Competence Centres, where National Grid Initiatives (NGIs), user communities, technology and service providers will join forces to collect requirements, integrate community-specific applications into state-of-the-art services, foster interoperability across e-Infrastructures, and evolve services through a user-centric development model. The project will also coordinate the NGI efforts to support the long-tail of science by developing ad hoc access policies and by providing services and resources that will lower barriers and learning curves.

Agency: Cordis | Branch: FP7 | Program: CSA | Phase: INFRA-2007-3.3;INFRA-2007-3.0-03 | Award Amount: 1.45M | Year: 2008

The EUAsiaGrid proposal contributes to the aims of the EU Research Infrastructures FP7 Programme by promoting international interoperation between similar infrastructures with the aim of reinforcing the global relevance and impact of European e-Infrastructures. The projects main goal will be to pave the way towards an Asian e-Science Grid Infrastructure, in synergy with the other European Grid initiatives in Asia, namely EGEE-III via its Asia Federation, and both the EUChinaGRID and EU-IndiaGRID projects and their eventual follow on efforts. Taking advantage of the existing global Grid technologies, with the specific emphasis on the European experience with the gLite middleware and applications running on top of it, the project plans to encourage federating approaches across scientific disciplines and communities. EUAsiaGrid will act as a support action, aiming to define and implement a policy to promote the gLite middleware developed within the EU EGEE project across Asian countries. Its main actions will be to spread dissemination, provide training, support scientific applications and monitor the results.

Agency: Cordis | Branch: FP7 | Program: CPCSA | Phase: INFRA-2010-1.2.1 | Award Amount: 70.14M | Year: 2010

Scientific research is no longer conducted within national boundaries and is becoming increasing dependent on the large-scale analysis of data, generated from instruments or computer simulations housed in trans-national facilities, by using e Infrastructure (distributed computing and storage resources linked by high-performance networks).\nThe 48 month EGI-InSPIRE project will continue the transition to a sustainable pan-European e-Infrastructure started in EGEE-III. It will sustain support for Grids of high-performance and high-throughput computing resources, while seeking to integrate new Distributed Computing Infrastructures (DCIs), i.e. Clouds, SuperComputing, Desktop Grids, etc., as they are required by the European user community. It will establish a central coordinating organisation, EGI.eu, and support the staff throughout Europe necessary to integrate and interoperate individual national grid infrastructures. EGI.eu will provide a coordinating hub for European DCIs, working to bring existing technologies into a single integrated persistent production infrastructure for researchers within the European Research Area.\nEGI-InSPIRE will collect requirements and provide user-support for the current and new (e.g. ESFRI) users. Support will also be given for the current heavy users as they move their critical services and tools from a central support model to ones driven by their own individual communities. The project will define, verify and integrate within the Unified Middleware Distribution, the middleware from external providers needed to access the e-Infrastructure. The operational tools will be extended by the project to support a national operational deployment model, include new DCI technologies in the production infrastructure and the associated accounting information to help define EGIs future revenue model.

Agency: Cordis | Branch: FP7 | Program: CSA-CA | Phase: KBBE-2009-1-4-10;KBBE-2009-1-4-11 | Award Amount: 1.20M | Year: 2009

This proposal builds on the outputs of the ASEM Aquaculture Platform, established in 2003 as an EU-Asia framework for dialogue, networking and continuing coordination for sustainable aquaculture development. From 2003-2006, 6 expert workshops targeted key topics (Disease & Health management, Biodiversity & Ecological impacts, Breeding & Domestication, Education, Food safety & Legislation, Food security) and yielded valuable recommendations on future directions in research, production and trade. With increasingly critical demands on aquaculture for food supply and food security, income and employment, the vulnerability of the natural resource issues involved, and the important gains to be realised through developing stronger scientific and economic partnerships between the two regions, the aim is to move more pro-actively into effective policy, into formulation of joint research goals, and into outcomes which contribute to Millennium Development and related goals. The projects major aim is to reconcile ecosystem and economic system demands to consolidate concepts of sustainability in aquaculture development in both regions. Specific actions include: 1) validation of earlier recommendations; 2) translating priority recommendations into concrete actions; 3) facilitate industry interaction between the two regions; 4) build and exchange knowledge and its application. The common denominator of the actions is the concerted effort to initiate joint EU-Asia processes which have impact on research excellence, contributing realistically and effectively to good production practice, improved governance, fair trade, social equity and sustainability. In developing these, the ASEM Aquaculture Platform will strengthen opportunities for the EU aquaculture sector to derive value from its technological and structural assets, and develop valuable trade partnerships, using the driver of import product quality to improve product quality and value in both markets.

Ramarad S.,University of Nottingham Malaysia Campus | Khalid M.,University of Nottingham Malaysia Campus | Ratnam C.T.,Malaysian Nuclear Agency | Chuah A.L.,University Putra Malaysia | Rashmi W.,Taylors University
Progress in Materials Science | Year: 2015

This review addresses the progress in waste tire recycling with a particular attention to incorporation of waste tire rubber (WTR) into polymeric matrices. Methods of waste tire downsizing, importance of WTR characterization and current practice of WTR modification has been emphasized. Detailed discussion on influence of WTR size, loading, modification, compatibilization and crosslinking on the rheological, mechanical and thermal properties of rubber, thermoplastic and thermoplastic elastomer blends utilizing WTR has been reported. By far, thermoplastic elastomer blends; though still in its infancy; has shown the most promising properties balance which is capable of commercialization. Rubber/WTR blends also show ease of processing and acceptable properties. Thermoplastic/WTR blends suffers in term of toughness and elongation at break. However, the waste thermoplastic/WTR is a viable solution to address polymeric waste problem. Review also highlights the lack of studies concentrating on dynamic mechanical, aging, thermal and swelling properties of WTR polymeric blends. © 2015 Elsevier Ltd All rights reserved.

Ahsan A.,University Putra Malaysia | Fukuhara T.,University of Fukui
Solar Energy | Year: 2010

In this paper, a new mass and heat transfer model of a Tubular Solar Still (TSS) was proposed incorporating various mass and heat transfer coefficients taking account of the humid air properties inside the still. The heat balance of the humid air and the mass balance of the water vapor in the humid air were formulized for the first time. As a result, the proposed model enabled to calculate the diurnal variations of the temperature, water vapor density and relative humidity of the humid air, and to predict the hourly condensation flux besides the temperatures of the water, cover and trough, and the hourly evaporation flux. The validity of the proposed model was verified using the field experimental results carried out in Fukui, Japan and Muscat, Oman in 2008. The diurnal variations of the calculated temperatures and water vapor densities had a good agreement with the observed ones. Furthermore, the proposed model can predict the daily and hourly production flux precisely. © 2010 Elsevier Ltd. All rights reserved.

Furtula V.,Environment Canada | Osachoff H.,Environment Canada | Derksen G.,Environment Canada | Juahir H.,University Putra Malaysia | And 2 more authors.
Water Research | Year: 2012

The effects of agricultural activities on stream water quality were assessed by nitrogen analysis, further investigated by gas chromatography mass spectrometry (GC-MS) sterol analysis (including chemometric analysis), and characterized by bacterial source tracking (BST). Surface water samples were collected from five sites, throughout the agriculturally-influenced Nathan Creek watershed, British Columbia, Canada and a nearby control site between October 2005 and March 2006. From a total of 48 samples, Canadian Water Quality Guidelines were exceeded nineteen times for nitrate (NO3-; guideline value: 2.94mg/L N) and four times for un-ionized ammonia (NH 3; guideline value 0.019mg/L N). Gas chromatography mass spectrometry single ion monitoring (GC-MS SIM) analysis of 18 sterols showed that five fecal sterols (coprostanol, episoprostanol, cholesterol, cholestanol, desmosterol) were detected at all sites except the control site (where only cholesterol, cholestanol and desmosterol were detected). Three phytosterols (campesterol, stigmasterol and β-sitosterol) were also detected at all sites while the hormone estrone was present at one site on two occasions at concentrations of 0.01 and 0.04μg/L. Chemometric analysis (principal component analysis and cluster analysis) grouped sites based on their similarities in sterol composition. Analysis of ten sterol ratios (seven for identifying human fecal contamination and four for differentiating sources of fecal contamination) showed multiple instances of human and animal contamination for every site but the control site. Application of a Bacteroides-BST method confirmed contamination from ruminant animals, pigs and dogs in varying combinations at all impact sites. Together, these results confirmed the impact of agricultural activities on the Nathan Creek watershed and support a need for better land management practices to protect water quality and aquatic life. © 2011.

Obeidat W.M.,University of Sharjah | Schwabe K.,Free University of Berlin | Muller R.H.,Free University of Berlin | Keck C.M.,University Putra Malaysia | Keck C.M.,Kaiserslautern University of Applied Sciences
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2010

Due to their positive features (e.g., increased penetration of actives, re-enforcement of the lipid barrier and increase in skin hydration), nanostructured lipid carriers (NLC) are used in many dermal formulations. These formulations require preservation, and preservatives can impair the physical stability of disperse systems. Therefore, in this study, the influence of preservatives on the physical stability of Q10-loaded NLC was investigated using 11 different preservative mixtures. Whereas for nanosuspensions, only a limited number of preservatives are known from the literature not affecting their physical stability, a surprisingly high number of seven preservatives could be identified to be suitable for the preservation of NLC dispersions. For Q10-loaded NLC, Hydrolite 5 proved to be the best preservative, as it was found surprisingly to stabilize the NLC dispersion. Based on the data, a preservative classification system is suggested and a mechanistic model describing six key parameters affecting the physical stability of NLC could be developed. As most suitable characterization method to screen for suitable preservatives, light microscopy was identified. By being a simple, fast and cost efficient method, even extensive preservative screening studies can be performed very efficiently. © 2010 Elsevier B.V.

Sulaiman Y.,Durham University | Sulaiman Y.,University Putra Malaysia | Kataky R.,Durham University
Analyst | Year: 2012

Chiral conducting polymers prepared by electropolymerising PEDOT in the presence of chiral anions such as hyaluronic acid and anionic collagen or in a chiral nematic phase (hydroxypropyl cellulose, HPC) show excellent chiral acid recognition. This paper demonstrates the enantioselective recognition and transfer of protonated mandelic acid and protons using chiral PEDOTs. Discrimination between (R)-(-)- and (S)-(+)-mandelic acid was observed using cyclic voltammetry and square-wave voltammetry. © 2012 The Royal Society of Chemistry.

Atiqah A.,International Islamic University Malaysia | Maleque M.A.,International Islamic University Malaysia | Jawaid M.,University Putra Malaysia | Iqbal M.,Malaysian Nuclear Agency
Composites Part B: Engineering | Year: 2014

The main aim of this paper is to develop kenaf-glass (KG) fibres reinforced unsaturated polyester hybrid composite on a source of green composite using sheet moulding compound process. Unsaturated polyester resin (UPE) and KG fibres in mat form were used at a ratio of 70:30 (by volume) with treated and untreated kenaf fibre. The kenaf fibre was treated with 6% sodium hydroxide (NaOH) diluted solution for 3 h using mercerization method. The hybrid composites were tested for flexural, tensile and Izod impact strength using ASTM D790-03, ASTM D618 and ASTM D256-04 standards respectively. The highest flexural, tensile and impact strength were obtained from treated kenaf with 15/15 v/v KG fibres reinforced UPE hybrid composite in this investigation. Scanning electron microscopy fractography showed fibre cracking, debonding and fibre pulled-out as the main fracture mode of composites and kenaf treated 15/15 v/v KG reinforced hybrid composite exhibited better interfacial bonding between the matrix and reinforcement compared to other combinations. © 2013 Elsevier Ltd. All rights reserved.

Jafari S.A.,University Putra Malaysia | Mashohor S.,University Putra Malaysia | Varnamkhasti M.J.,Institute for Mathematical Research
Journal of Petroleum Science and Engineering | Year: 2011

Combining numerous appropriate experts can improve the generalization performance of the group when compared to a single network alone. There are different ways of combining the intelligent systems' outputs in the combiner in the committee neural network, such as simple averaging, gating network, stacking, support vector machine, and genetic algorithm. Premature convergence is a classical problem in finding optimal solution in genetic algorithms. In this paper, we propose a new technique for choosing the female chromosome during sexual selection to avoid the premature convergence in a genetic algorithm. A bi-linear allocation lifetime approach is used to label the chromosomes based on their fitness value, which will then be used to characterize the diversity of the population. The label of the selected male chromosome and the population diversity of the previous generation are then applied within a set of fuzzy rules to select a suitable female chromosome for recombination. Finally, we use fuzzy genetic algorithm methods for combining the output of experts to predict a reservoir parameter in petroleum industry. The results show that the proposed method (fuzzy genetic algorithm) gives the smallest error and highest correlation coefficient compared to five members and genetic algorithm and produces significant information on the reliability of the permeability predictions. © 2011 Elsevier B.V.

Saw K.-Y.,Kuala Lumpur Sports Medicine Center | Anz A.,Andrews Research and Education Institute | Siew-Yoke Jee C.,Kuala Lumpur Sports Medicine Center | Merican S.,Kuala Lumpur Sports Medicine Center | And 3 more authors.
Arthroscopy - Journal of Arthroscopic and Related Surgery | Year: 2013

Purpose: The purpose of this study was to compare histologic and magnetic resonance imaging (MRI) evaluation of articular cartilage regeneration in patients with chondral lesions treated by arthroscopic subchondral drilling followed by postoperative intra-articular injections of hyaluronic acid (HA) with and without peripheral blood stem cells (PBSC). Methods: Fifty patients aged 18 to 50 years with International Cartilage Repair Society (ICRS) grade 3 and 4 lesions of the knee joint underwent arthroscopic subchondral drilling; 25 patients each were randomized to the control (HA) and the intervention (PBSC + HA) groups. Both groups received 5 weekly injections commencing 1 week after surgery. Three additional injections of either HA or PBSC + HA were given at weekly intervals 6 months after surgery. Subjective IKDC scores and MRI scans were obtained preoperatively and postoperatively at serial visits. We performed second-look arthroscopy and biopsy at 18 months on 16 patients in each group. We graded biopsy specimens using 14 components of the International Cartilage Repair Society Visual Assessment Scale II (ICRS II) and a total score was obtained. MRI scans at 18 months were assessed with a morphologic scoring system. Results: The total ICRS II histologic scores for the control group averaged 957 and they averaged 1,066 for the intervention group (P =.022). On evaluation of the MRI morphologic scores, the control group averaged 8.5 and the intervention group averaged 9.9 (P =.013). The mean 24-month IKDC scores for the control and intervention groups were 71.1 and 74.8, respectively (P =.844). One patient was lost to follow-up. There were no notable adverse events. Conclusions: After arthroscopic subchondral drilling into grade 3 and 4 chondral lesions, postoperative intra-articular injections of autologous PBSC in combination with HA resulted in an improvement of the quality of articular cartilage repair over the same treatment without PBSC, as shown by histologic and MRI evaluation. Level of Evidence: Level II, randomized controlled trial (RCT). © 2013 by the Arthroscopy Association of North America.

Falamarzi Y.,University Putra Malaysia | Palizdan N.,University Putra Malaysia | Huang Y.F.,University Tunku Abdul Rahman | Lee T.S.,University Putra Malaysia
Agricultural Water Management | Year: 2014

Evapotranspiration (ET) is a major component of the hydrologic cycle and its accurate forecasting is essential in all water resources applications. In this study, artificial neural network (ANN) and wavelet neural network (WNN) were utilized to forecast daily ET from temperature and wind speed data. The WNN model used in this study is a neural network model with one hidden layer and a wavelet function as an activation function. The climatic data of Redesdale climatology station, Australia for the period 2009-2012 were utilized for the analysis. The daily reference values of ET were calculated by the FAO-PM56 method. The maximum temperature, minimum temperatures and wind speed data were used as the inputs and the reference values of ET data series was utilized as the output of the ANN and WNN models. In order to assess the effect of decomposing the input data by wavelet transform on the models efficiency, the original dataset and separately the decomposed time series were applied for calibrating and validating the models. The influence of using wind speed data as the third input on the performance of models was also investigated. The results showed that both the ANN and WNN models predicted ET at an acceptable accuracy level. However, the wavlet-WNN261 (2 inputs, 6 neurons in the hidden layer and one output) performed the best with the RMSE, APE, N.S. and R values of 1.03. mm/day, 22%, 0.79 and 0.89, respectively. © 2014 Elsevier B.V.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Jason W.S.Y.,Monash University | Cherrington T.,Monash University | Danquah M.K.,Monash University
Applied Energy | Year: 2011

We have investigated, for the first time, the alkaline pre-treatment of microalgal biomass, from the species Chlorococcum infusionum, using NaOH for bioethanol production. This pre-treatment step aims to release and breakdown entrapped polysaccharides in the microalgae cell walls into fermentable subunits. Three parameters were examined here; the concentration of NaOH, temperature and the pre-treatment time. The bioethanol concentration, glucose concentration and the cell size were studied in order to determine the effectiveness of the pre-treatment process. Microscopic analysis was performed to confirm cell rupturing, the highest glucose yield was determined to be 350. mg/g, and the maximum bioethanol yield obtained was 0.26. g ethanol/g algae using 0.75% (w/v) of NaOH and 120 °C for 30. min. Overall, the alkaline pre-treatment method proved to be promising option to pre-treat microalgal biomass for bioethanol production. © 2010 Elsevier Ltd.

Hii S.L.,University Tunku Abdul Rahman | Tan J.S.,University Putra Malaysia | Ling T.C.,University of Malaya | Ariff A.B.,University Putra Malaysia
Enzyme Research | Year: 2012

The use of pullulanase (EC has recently been the subject of increased applications in starch-based industries especially those aimed for glucose production. Pullulanase, an important debranching enzyme, has been widely utilised to hydrolyse the α-1,6 glucosidic linkages in starch, amylopectin, pullulan, and related oligosaccharides, which enables a complete and efficient conversion of the branched polysaccharides into small fermentable sugars during saccharification process. The industrial manufacturing of glucose involves two successive enzymatic steps: liquefaction, carried out after gelatinisation by the action of α-amylase; saccharification, which results in further transformation of maltodextrins into glucose. During saccharification process, pullulanase has been used to increase the final glucose concentration with reduced amount of glucoamylase. Therefore, the reversion reaction that involves resynthesis of saccharides from glucose molecules is prevented. To date, five groups of pullulanase enzymes have been reported, that is, (i) pullulanase type I, (ii) amylopullulanase, (iii) neopullulanase, (iv) isopullulanase, and (v) pullulan hydrolase type III. The current paper extensively reviews each category of pullulanase, properties of pullulanase, merits of applying pullulanase during starch bioprocessing, current genetic engineering works related to pullulanase genes, and possible industrial applications of pullulanase. © 2012 Siew Ling Hii et al.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Singh M.,Monash University | Forde G.M.,Monash University | Danquah M.K.,Monash University
Renewable and Sustainable Energy Reviews | Year: 2010

Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. © 2009 Elsevier Ltd. All rights reserved.

Zan Z.,Monash University | Zan Z.,University Putra Malaysia | Lowery A.J.,Monash University
Optics Express | Year: 2010

We propose and demonstrate experimentally a laser source whose linewidth is adjustable independently of its other characteristics. This source can be used to test whether a particular laser would be suitable in a system, without the need to purchase several different lasers. It also has the advantage that the linewidth is generated digitally so it is extremely stable over time. We demonstrate a dialed-linewidth emulator between 256 kHz to 150 MHz. The narrowest linewidth shown by this technique is the original linewidth of the semiconductor laser source used in the setup. We also investigate the effect of driving our modulator into its nonlinear range. ©2010 Optical Society of America.

Shee Y.G.,University Putra Malaysia | Shee Y.G.,University Tunku Abdul Rahman | Al-Mansoori M.H.,Sohar University | Ismail A.,University Putra Malaysia | And 2 more authors.
Optics Express | Year: 2011

We demonstrate a multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing. The wider channel spacing is realized by circulating the odd-order Stokes signals in the Brillouin gain medium through a four-port circulator. The circulated odd-order Stokes signals are amplified by the Brillouin gain and thus produce even-order Stokes signals at the output. These signals are then amplified by erbium gain block to form a ring-cavity laser. Ten channels with 0.174 nm spacing that are generated at 0.5 mW Brillouin pump power and 150 mW pump power at 1480 nm can be tuned from 1556 nm to 1564 nm. The minimum optical signal-to-noise ratio of the generated output channels is 30 dB with maximum power fluctuations of ±0.5 dB. © 2011 Optical Society of America.

Naji A.,Islamic Azad University at Tehran | Ismail A.,University Putra Malaysia
Aquatic Ecosystem Health and Management | Year: 2012

This investigation was conducted to determine metals contamination from anthropogenic sources in sediments of Klang Estuary. Surface sediments from Klang Estuary were analyzed for metals (Cd, Zn, Ni, Cu, Pb and Fe), organic carbon and particles sizes. Quality assessment of sediments was evaluated using modified degree of contamination (mCd) and pollution load index (PLI). A comparison was also made with sediment quality guideline values. The present study showed that highest concentrations of metals were found in stations with high anthropogenic discharge. The mCd and PLI suggested that degree of metals contamination in surface sediments could be classified as "low to moderate degree of contamination." With the rapid economic development and urbanization around the Klang Estuary, ongoing monitoring studies on heavy metals contamination should focus on contaminant sources within the estuary. © 2012 Copyright Taylor and Francis Group, LLC.

Liam C.-K.,University of Malaya | Wahid M.I.A.,Beacon International Specialist Center | Rajadurai P.,Monash University | Cheah Y.-K.,University Putra Malaysia | Ng T.S.-Y.,University Putra Malaysia
Journal of Thoracic Oncology | Year: 2013

Introduction: Despite available data from other Asian countries, the prevalence of epidermal growth factor receptor (EGFR) mutations among lung adenocarcinoma patients has not been reported in Malaysia. This study sought to determine the frequency of EGFR mutations among multiethnic Malaysian patients diagnosed with lung adenocarcinoma. Methods: Demographic and clinical information of patients whose lung adenocarcinoma biopsy specimens were submitted for EGFR mutation testing at Sime Darby Medical Center from 2009 to 2011 were analyzed. EGFR mutations at exons 18, 19, 20, and 21 were detected either through bidirectional sequencing or real-time polymerase chain reaction. Results: Among 812 patients in the study, 49% were female, 63.7% were ethnic Chinese, 29.4% Malay, 4.8% Indian, and 2.1% other ethnic groups. Mutations were present in the tumors of 321 patients (39.5%), with mutations at exons 19 (23.5%) and 21 (14.9%) being the most common. Mutations were significantly more frequent among women than in men (52.5% versus 27.8%, p < 0.001). Although mutations were more common among Chinese (40.8%) compared with Malay (37.2%) or Indian (33.3%) patients, the difference was not statistically significant (p = 0.591). Of 211 patients with smoking history records, never-smokers had a higher mutation rate compared with ever-smokers (54.8% versus 20.7%, p < 0.001). Conclusion: EGFR mutations were present in 39.5% of patients. Mutations were more common in women and never-smokers with no differences in mutation frequency between different ethnicities. Because of the high mutation rates, reflex testing for EGFR mutation should be a routine practice for advanced lung adenocarcinoma patients in Malaysia. Copyright ©2013 by the International Association for the Study of Lung Cancer.

A. Bakar B.F.,University Putra Malaysia | Hiziroglu S.,Oklahoma State University | Md Tahir P.,University Putra Malaysia
Materials and Design | Year: 2013

The objective of the study was to investigate the influence of heat treatment and exposure time on surface roughness, wettability, shear strength and hardness of rubberwood, Eastern redcedar and red oak samples. The anatomical structure of each species was also observed using scanning electron microscope (SEM). All specimens were exposed to two different temperature levels, namely 120. °C and 190. °C for 2 and 8. h. Red oak samples had the most enhanced surface quality along with less wettability characteristics followed by rubberwood and Eastern redcedar specimens as function of increased heat exposure. On the other hand, it appears that heat exposure adversely affected shear strength and hardness properties of all three types of samples. These two properties of heat treated samples had reduction values ranging from 52.7% to 69.4% and 10.8% to 33.3%, respectively as compared to those of control samples. © 2012.

Arab A.,Islamic Azad University at Tehran | Ismail N.,University Putra Malaysia | Lee L.S.,University Putra Malaysia
Journal of Intelligent Manufacturing | Year: 2013

In this paper, a new approach to maintenance scheduling for a multi-component production system which takes into account the real-time information from workstations including remaining reliability of equipments as well as work-in-process inventories in each workstation is proposed. To model dynamics of the system, other information like production line configuration, cycle times, buffers' capacity and mean time to repair of machines are also considered. Using factorial experiment design the problem is formulated to comprehensively monitor the effects of each possible schedule on throughput of the production system. The optimal maintenance schedule is searched by genetic algorithm-based optimization engine implemented in a simulation optimization platform. The proposed approach exploits all of makespans of planning horizon to find the best opportunity to perform maintenance actions on degrading machines in a way that maximizes the system throughput and mitigates the production losses caused by imperfect traditional maintenance strategies. Finally the proposed method is tested in a real production line to magnify the accuracy of proposed scheduling method. The experimental results indicate that the proposed approach guarantees the operational productivity and scheduling efficiency as well. © 2011 Springer Science+Business Media, LLC.

Zakaria R.,University Putra Malaysia | Harvey A.P.,Newcastle University
Fuel Processing Technology | Year: 2012

Biodiesel is a fuel derived from renewable resources such as edible and inedible oil-bearing seed, algae, and waste cooking oil. The conventional biodiesel process involves oil extraction, refining and transesterification. Alternatively, transesterification can actually be performed directly from the oil-bearing materials without prior extraction. This route which is often termed reactive extraction or in situ transesterification has the advantages of simplifying the biodiesel production process as well as potentially reducing production cost. In this study, the reactive extraction of rapeseed with methanol has been characterised. The effects of process parameters on the yield, conversion and reaction rate differ substantially from conventional transesterification due to the dependence on both extraction and reaction. The rate of ester formation is mainly affected by the catalyst concentration, temperature and particle size while the equilibrium yield largely depends on the solvent to oil molar ratio. A high yield of ester (> 85%) can only be achieved at high solvent to oil molar ratios (> 475:1). Parametric studies and light microscope images of reactively extracted seed suggested that reactive extraction occurs by transesterification of the oil inside the seed, followed by diffusion of the products into the bulk solvent. © 2012 Elsevier B.V.

Khataee H.R.,University Putra Malaysia | Ibrahim M.Y.,Monash University
IET Nanobiotechnology | Year: 2012

Kinesin is a protein-based natural nanomotor that transports molecular cargoes within cells by walking along microtubules. Kinesin nanomotor is considered as a bio-nanoagent which is able to sense the cell through its sensors (i.e. its heads and tail), make the decision internally and perform actions on the cell through its actuator (i.e. its motor domain). The study maps the agent-based architectural model of internal decision-making process of kinesin nanomotor to a machine language using an automata algorithm. The applied automata algorithm receives the internal agent-based architectural model of kinesin nanomotor as a deterministic finite automaton (DFA) model and generates a regular machine language. The generated regular machine language was acceptable by the architectural DFA model of the nanomotor and also in good agreement with its natural behaviour. The internal agent-based architectural model of kinesin nanomotor indicates the degree of autonomy and intelligence of the nanomotor interactions with its cell. Thus, our developed regular machine language can model the degree of autonomy and intelligence of kinesin nanomotor interactions with its cell as a language. Modelling of internal architectures of autonomous and intelligent bio-nanosystems as machine languages can lay the foundation towards the concept of bio-nanoswarms and next phases of the bio-nanorobotic systems development. © 2012 The Institution of Engineering and Technology.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University
Process Biochemistry | Year: 2011

The utilisation of microalgal biomass as feedstock for bioethanol production has been very promising owing to the large amounts of carbohydrates embedded in the physiology of the microalgal cell. This is coupled with the potential of microalgae to achieve targets required for high growth rate bioethanol production, climate change mitigation and economic growth. The high content of complex carbohydrates entrapped in the cell wall of the microalgae makes it essential to incorporate a pre-treatment stage to release and convert these complex carbohydrates into simple sugars prior to the fermentation process. Hence, this study explores the influence of acid exposure as a microalgal pre-treatment strategy for bioethanol production. Different parameters were investigated: acid concentration, temperature, microalgae loading and pre-treatment time. A central composite design technique was employed to optimize the acid pre-treatment conditions. Results showed that the highest bioethanol concentration obtained was 7.20 g/L and this was achieved when the pre-treatment step was performed with 15 g/L of microalgae at 140 °C using 1% (v/v) of sulphuric acid for 30 min. In terms of ethanol yield, ∼52 wt% (g ethanol/g microalgae) maximum was obtained using 10 g/L of microalgae and 3% (v/v) of sulphuric acid under 160 °C for 15 min. The statistical analysis revealed amongst the parameters investigated that temperature is the most critical factor during acid pre-treatment of microalgae for bioethanol production. © 2010 Elsevier Ltd. All rights reserved.

Byrne S.N.,University of Sydney | Byrne S.N.,Royal Prince Alfred Hospital | Sarchio S.N.E.,University of Sydney | Sarchio S.N.E.,Royal Prince Alfred Hospital | Sarchio S.N.E.,University Putra Malaysia
OncoImmunology | Year: 2014

Sunlight causes skin cancer by directly damaging DNA as well as by suppressing antitumor immune responses. A major mechanism whereby sunlight exerts immunosuppressive effects is by modulating the migration of chemokine (C-X-C motif) receptor 4 (CXCR4)-expressing dermal mast cells into and away from the skin. We have demonstrated the importance of this by showing that the systemic administration of the CXCR4 antagonist AMD3100 prevents sunlightinduced immunosuppression as well as the consequent carcinogenic response. Our results highlight the therapeutic potential of antagonizing CXCR4 signaling, especially in individuals who are at high risk of developing skin cancer. © 2014 Landes Bioscience.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University | Forde G.M.,Monash University
Journal of Chemical Technology and Biotechnology | Year: 2010

BACKGROUND: The increasing cost of fossil fuels as well as the escalating social and industrial awareness of the environmental impacts associated with the use of fossil fuels has created the need for more sustainable fuel options. Bioethanol, produced from renewable biomass such as sugar and starch materials, is believed to be one of these options, and it is currently being harnessed extensively. However, the utilization of sugar and starch materials as feedstocks for bioethanol production creates a major competition with the food market in terms of land for cultivation, and this makes bioethanol from these sources economically less attractive. RESULT: This study explores the suitability of microalgae (Chlorococum sp.) as a substrate for bioethanol production via yeast (Saccharomycesbayanus)under different fermentation conditions. Results show a maximum ethanol concentration of 3.83 g L -1 obtained from 10 g L-1 of lipid-extracted microalgae debris. CONCLUSION: This productivity level (∼38% w/w), which is in keeping with that of current production systems endorses microalgae as a promising substrate for bioethanol production. © 2009 Society of Chemical Industry.

Juan J.C.,University of Technology Malaysia | Kartika D.A.,University of Technology Malaysia | Wu T.Y.,Monash University | Hin T.Y.Y.,University Putra Malaysia
Bioresource Technology | Year: 2011

Biodiesel (fatty acids alkyl esters) is a promising alternative fuel to replace petroleum-based diesel that is obtained from renewable sources such as vegetable oil, animal fat and waste cooking oil. Vegetable oils are more suitable source for biodiesel production compared to animal fats and waste cooking since they are renewable in nature. However, there is a concern that biodiesel production from vegetable oil would disturb the food market. Oil from Jatropha curcas is an acceptable choice for biodiesel production because it is non-edible and can be easily grown in a harsh environment. Moreover, alkyl esters of jatropha oil meet the standard of biodiesel in many countries. Thus, the present paper provides a review on the transesterification methods for biodiesel production using jatropha oil as feedstock. © 2010.

Rownaghi A.A.,Monash University | Taufiq-Yap Y.H.,University Putra Malaysia
Industrial and Engineering Chemistry Research | Year: 2010

The vanadyl hydrogen phosphate hemihydrate (VOHPO4 • 0.5H2O), with well-defined crystal size, has been successfully synthesized for the first time, using a simple one-step solvothermal process that was free of surfactants and water and had a short reaction time and low temperature. The synthesis was performed via the reaction of V2O 5 and H3PO4 with an aliphatic alcohol (1-propanol or 1-butanol) at high temperatures (373, 393, and 423 K) in a high-pressure autoclave. The mixture of reactions directly gave the VOHPO 4 • 0.5H2O, which is a valuable commercial catalyst precursor for the selective oxidation of n-butane to maleic anhydride. The catalyst precursors were dried by microwave irradiation. The reaction conditions (by varying the reducing agent and reaction temperature) were used further for optimization of the crystallite size, surface area, morphology, and activity of the nanostructure of vanadium phosphate oxide [(VO)2P 2O7] catalyst. This new method significantly reduced the preparation time and lowered the production temperature (50%) of catalyst precursor (VOHPO4 • 0.5H2O), when compared to conventional hydrothermal synthesis methods. The as-prepared (VO) 2P2O7 catalyst under various conditions exhibited remarkably different physical and chemical properties, indicating the potential of the suggested method in tuning the crystalline structure and surface area of (VO)2P2O7 to improve its catalytic performance. It was found that the length of the carbon chain in an alcohol and reaction temperature in the solvothermal condition had a great impact on the chemical and physical properties of resulting catalysts. Interestingly, there was no trace of VO(H2PO4) 2, which is an impurity noted to be readily formed under solvothermal preparation conditions. The precursors and catalysts were characterized using a combination of powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurement, scanning electron microscopy (SEM), and temperature-programmed reduction in hydrogen (H2-TPR). A correlation between the surface area of the catalyst and the activity was observed. Finally, the yield of maleic anhydride was significantly increased from 21% for conventional catalyst to 38% for the new solvothermal catalyst. © 2010 American Chemical Society.

Farah R.N.,Sultan Idris University of Education | Othman M.,University Putra Malaysia
Applied Mathematics and Information Sciences | Year: 2014

The design of the interconnection network is one of the main research issues in distributed computing with regard to some specific parameters. This paper works on Modified Chordal Rings Degree Six (CHRm6) topology. Two broadcasting schemes for CHRm6 are proposed. The first scheme is for even source nodes and the second scheme is for odd source nodes. The proposed broadcasting schemes give upper and lower bound of broadcasting in CHRm6 depends on total number of nodes. We prove the lower bound on the broadcast time is d+2 where d is the diameter of the CHRm6. © 2014 NSP Natural Sciences Publishing Cor.

Khaw C.C.,University Tunku Abdul Rahman | Tan K.B.,University Putra Malaysia | Lee C.K.,Academic Science Malaysia | West A.R.,University of Sheffield
Journal of the European Ceramic Society | Year: 2012

The complete subsolidus phase diagram of the system Bi2O3-ZnO-Ta2O5, including cubic pyrochlore and monoclinic zirconolite phases, has been determined at 950-1050°C. Through systematic heat treatment and X-ray diffraction of over 100 compositions, the layout of compatibility triangles (both 2-phase and 3-phase) and single phase solid solution areas has been determined. Pyrochlore and zirconolite phases have ideal nominal compositions Bi1.5Zn1.0Ta1.5O7 and Bi2(Zn1/3Ta2/3)2O7 respectively, but both form solid solution areas. The sintering condition of pyrochlore pellets has been optimised to obtain high density ceramics with minimal weight loss: optimised condition is 1100°C for pellets covered with sacrificial powder. Permittivity, e{open}' dielectric loss and temperature coefficient of capacitance, TCC, of single phase materials were measured using impedance spectroscopy; e{open}' and TCC show little variation with composition but the losses are higher for Zn-deficient compositions. © 2011 Elsevier Ltd.

Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University
Chemical Engineering Journal | Year: 2011

Increasing global energy demands and the potential for significant climate change have led to burgeoning interest in alternative fuels which are sustainable, environmentally friendly and cost efficient. One of the key options is to produce bioethanol from renewable biomass. Due to its numerous advantages, including fast growth rate, non-edibility, and the ability to accumulate substantial amounts of carbohydrates, microalgae, a second generation cellular biomass, have the potential to be used as a fermentation feedstock for bioethanol production. The present study examines the enzymatic hydrolysis of Chloroccum sp. by using cellulase obtained from Trichoderma reesei, ATCC 26921. The hydrolysis was conducted under varying conditions of temperature, pH and substrate concentration, with constant enzyme dosage. The kinetics of hydrolysis was fitted with Michaelis-Menten's model of rapid equilibrium. The highest glucose yield of 64.2% (w/w) was obtained at a temperature of 40°C, pH 4.8, and a substrate concentration of 10g/L of microalgal biomass. Comparative kinetic studies on glucose and cellobiose formation showed twice as fast glucose production than cellulobiose. The value of K m,app was higher for the hydrolysis of cellobiose (K m,app=15.18g/L) compared to that of the substrate (K m,app=1.48g/L), thus displaying a competitive type of inhibition. The results were in keeping with the obtained reaction velocities. Overall, the enzymatic hydrolysis process proved to be an effective mechanism to enhance the saccharification process of microalgal biomass. © 2011 Elsevier B.V.

Leong L.K.,University Tunku Abdul Rahman | Chin K.S.,University Tunku Abdul Rahman | Taufiq-Yap Y.H.,University Putra Malaysia
Applied Catalysis A: General | Year: 2012

A series of vanadyl pyrophosphate, (VO) 2P 2O 7, catalysts prepared via vanadyl hydrogen phosphate sesquihydrate precursors (VOHPO 4·1.5H 2O) was calcined in a reaction flow of 0.75% n-butane in air mixture at 733 K for 18 h. The precursors have been synthesized by refluxing vanadyl phosphate dihydrate (VOPO 4·2H 2O) with 1-butanol for different lengths of time, i.e. 8, 15 and 24 h, and the produced catalysts were denoted as VPO s-R8, VPO s-R15 and VPO s-R24, respectively. X-ray diffraction (XRD) patterns of the three catalysts showed similar diffraction pattern, comprised of a well-crystallized (VO) 2P 2O 7 phase. Brunauer-Emmett-Teller (BET) surface area measurements showed that VPO s-R24 has the highest specific surface area, i.e. 31 m 2 g -1 followed by 27 m 2 g -1 and 19 m 2 g -1 for VPO s-R15 and VPO s-R8, respectively. Inductively coupled plasma (ICP) analyses indicated that the P/V atomic ratios of these catalysts were in the optimum range in producing (VO) 2P 2O 7 phase. A small increment in the average oxidation number of the vanadium was observed as the precursor reflux duration increased. Scanning electron microscope showed the secondary structures of the catalysts with plate-like crystals in different sizes, which were agglomerated into rosette-shape clusters. The total amount of oxygen desorbed from the catalysts increased as the precursor reflux duration increased. Temperature-programmed reduction (TPR) in H 2 profiles of all the catalysts gave three reduction peaks. VPO s-R8 gave the highest total amount of oxygen removed from V 5+/V 4+ phase followed by VPO s-R15 and VPO s-R24. Catalytic tests revealed that the catalyst with lower precursor reflux duration exhibited higher selectivity but lower activity and vice versa. © 2011 Elsevier B.V. All rights reserved.

Naghavi F.,Islamic Azad University at Tehran | Redzuan M.,University Putra Malaysia
Life Science Journal | Year: 2012

With respect to the relationship between family functioning, alexithymia, and the early adolescent's emotional intelligence construct is still being developed with empirical support. Hence, this research follows a specific objective for determination of the relationship between family functioning, alexithymia, and early adolescent's emotional intelligence (EQ). EQ is a set of abilities such as conception, emotion appraisal and expression, emotion management and regulation, and emotion utilization of emotion. The present study was carried out among 234 Iranian students in the second and grades of guidance schools (age 12-15) in Tehran, Iran. The students (girls and boys) were clustered through random and multistage sampling. Data were collected using the Schutte's (1998) Emotional Intelligence Scale and Rieffe's Children's Alexithymia Scale (2006), which are consistent with the original adult questionnaire for alexithymia (TAS-20) in the first stage and Family Assessment Device (FAD), based on McMaster's model in the second stage. Pearson correlation between subscales of total family functioning and alexithymia and emotional intelligence was statistically significant. Results of the multiple regression analysis, together with independent variables entered, simultaneously indicate that as a group, the independent variables significantly contributed to the prediction of emotional intelligence.

Malekbala M.R.,Islamic Azad University at Tehran | Hosseini S.,University Putra Malaysia | Kazemi Yazdi S.,University of Nottingham Malaysia Campus | Masoudi Soltani S.,University of Nottingham Malaysia Campus
Chemical Engineering Research and Design | Year: 2012

This study utilizes sugar beet pulp as a low-cost absorbent to remove two different cationic dyes, methylene blue and safranin, in aqueous solutions. The effects of operational parameters on the efficiency of dye removal including pH, adsorbent mass, initial dye concentration and contact time have been investigated. All sets of experiments were carried out in batch mode. For both dyes, the maximum absorption was reached at pH 10 while point zero charge was known to be at pH 6. Boehm method showed that the amount of the acidic and basic groups have been 0.4075mmolg -1 and 0.0089mmolg -1, respectively. Freundlich and Langmuir models were used to analyse the obtained experimental data. In comparison, Langmuir model was understood to be a better fit for the experimental data than Freundlich model. Pseudo first-order and pseudo second-order models were used to determine the adsorption kinetics and it was observed that pseudo second-order model was the most suited model for both dyes. The equilibrium state for both dyes was reached after 210min of the absorption experiment with more than 93% removal of dyes. The absorption capacities were found to be 211mg/g and 147mg/g for methylene blue and safranin, respectively. © 2011 The Institution of Chemical Engineers.

Saberi A.H.,University Putra Malaysia | Lai O.-M.,University Putra Malaysia | Toro-Vazquez J.F.,Autonomous University of San Luis Potosi
Food Research International | Year: 2011

Crystallization kinetics of palm oil (PO) in the presence of different concentrations (2, 5, 10, 30 and, 50% w/w) of palm-based diacylglycerol (PB-DAG) were investigated over different ranges of crystallization temperatures. Addition of 30 and 50% (w/w) of PB-DAG (high concentrations) increased significantly (P<0.05) the melting point and crystallization onset while addition of 2 and 5% PB-DAG did not have significant (P>0.05) effect. PO and PO blends with 2 and 5% of PB-DAG showed crystal transformation at crystallization temperatures (TCr) of 26, 26, 26.5°C, respectively as reflected in corresponding changes of the Avrami parameters at below and above these TCr. This was especially evident for the blends containing 2 and 5% of PB-DAG. Individual comparison of induction time (Ti), Avrami exponent (n), Avrami constant (k) and half-time of crystallization (t1/2) of blends classified under various supercooling ranges based on the supercooling closeness (±0.1°C), showed that addition of 5% of PB-DAG in most of the supercooling ranges significantly (P<0.05) reduced nucleation rate as well as crystal growth velocity of PO. This was reflected in the significantly (P<0.05) higher Ti and t1/2 and lower k. Although the presence of 2% of PB-DAG was found to have inhibitory effect on PO crystallization, this effect was not significant (P>0.05). Mode of crystal growth attributed to n was changed significantly only in presence of 5% of PB-DAG. Furthermore, presence of 10% PB-DAG showed β'-stabilizing effect on PO. On the other hand, high concentrations of PB-DAG were found to significantly (P<0.05) reduce Ti as well as t1/2 and also increase k suggesting their promoting effects on nucleation and crystallization rate of PO even with the close supercoolings. In addition, they changed crystal growth mode of PO. Amongst the different concentrations of PB-DAG investigated, blend containing 50% of PB-DAG as compared to PO, not only, have healthier benefits but also, may have greater potential applications in plastic fat products due to its unique physical properties. © 2010 Elsevier Ltd.

Halim R.,Monash University | Harun R.,Monash University | Harun R.,University Putra Malaysia | Danquah M.K.,Monash University | Webley P.A.,Monash University
Applied Energy | Year: 2012

The production of alternative fuels from microalgae involves lengthy processing steps. Cell disruption is an integral part of the downstream pool of unit operations as it facilitates the release of intracellular products essential for biofuel production. This study investigated the use of high-pressure homogenization, ultrasonication, bead beating, and sulfuric acid treatment as laboratory-scale disruption methods for microalgal cells. The performance of each cell disruption method was evaluated in terms of two key indicators: reduction in the intact cell count and reduction in the average colony diameter. The microalgal strain, Chlorococcum sp., was used throughout the study. The most effective disruption was obtained using high-pressure homogenization (average disruption = 73.8% of initial intact cells) followed by sulfuric acid treatment (average disruption = 33.2% of initial intact cells) and bead beating (average disruption = 17.5% of initial intact cells). Even though ultrasonication failed to disrupt the microalgal cells under the investigated conditions (average disruption = 4.5% of initial intact cells), it still managed to disintegrate cellular colonies. © 2011 .

Jonoobi M.,University Putra Malaysia | Jonoobi M.,Lulea University of Technology | Harun J.,University Putra Malaysia | Mathew A.P.,Lulea University of Technology | Oksman K.,Lulea University of Technology
Composites Science and Technology | Year: 2010

The aim of this study was to develop cellulose nanofiber (CNF) reinforced polylactic acid (PLA) by twin screw extrusion. Nanocomposites were prepared by premixing a master batch with high concentration of CNFs in PLA and diluting to final concentrations (1, 3, 5 wt.%) during the extrusion. Morphology, mechanical and dynamic mechanical properties (DMA) were studied theoretically and experimentally to see how different CNF concentrations affected the composites' properties. The tensile modulus and strength increased from 2.9. GPa to 3.6. GPa and from 58. MPa to 71. MPa, respectively, for nanocomposites with 5. wt.% CNF. The DMA results were also positive; the storage modulus increased for all nanocomposites compared to PLA; being more significant in the high temperature region (70°C). The addition of nanofibers shifted the tan delta peak towards higher temperatures. The tan delta peak of the PLA shifted from 70°C to 76°C for composites with 5. wt.% CNF. © 2010 Elsevier Ltd.

Davoodi H.,Golestan University of Medical Sciences | Davoodi H.,University Putra Malaysia | Seow H.F.,University Putra Malaysia
Iranian Journal of Allergy, Asthma and Immunology | Year: 2011

The innate immune system recognizes the presence of bacterial products through the expression of a family of membrane receptors known as Toll-like receptors (TLRs). Polymorphisms in TLRs have been shown to be associated with increased susceptibility to diseases such as inflammatory bowel disease. The aim of this study was to determine whether there was a correlation between polymorphisms of TLR4 (Asp299Gly; Thr399Ile) and TLR2 (Arg677Trp; Arg753Gln) genes and risk of colorectal cancer. DNA from 60 colorectal carcinoma patients from 3 major races in Malaysia (22 Malays, 20 Chinese and 18 Indians) and blood from 50 apparently healthy individuals were evaluated. Control group were matched to study group by race and age. The polymorphisms were determined by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Genotyping results showed two out of sixty tumor specimens (3.3%) harbored both variant TLR4 Asp299Gly and Thr399Ile alleles. In contrast, DNA isolated from blood cells of 50 apparently healthy individuals harbored wild type TLR4. In the case of TLR2 Arg753Gln genotyping, all of the fifty normal and 60 tumors were of the wild type genotype. TLR2 Arg677Trp genotyping showed a heterozygous pattern in all samples. However, this may not be a true polymorphism of the TLR2 gene as it is likely due to a variation of a duplicated (pseudogene) region. There was only a low incidence (2/60; 3.3%) of TLR4 polymorphism at the Asp299Gly and Thr399Ile alleles in colorectal cancer patients. All normal and tumor samples harbored the wild type TLR2 Arg753 allele. Our study suggests that variant TLR4 (Asp299Gly and Thr399Ile alleles) as well as TLR2 (Arg753Gln allele) are not associated with risk of colorectal cancer. Copyright© 2011, Iranian Journal of Allergy, Asthma and Immunology. All rights reserved.

Al-Mansoori M.H.,Sohar University | Ajiya M.,Bayero University | Mahdi M.A.,University Putra Malaysia
IEEE Photonics Journal | Year: 2012

An efficient L-band multiple-wavelength Brillouin-erbium fiber laser is presented. We configured a linear cavity resonator where the cavity ends are made up of high-reflectivity optical mirror on one side and an amplified fiber loop mirror on the other. This laser architecture provides amplification intensity-dependent transmission and allows the preamplification of the Brillouin pump (BP) signal before being injected into the Brillouin gain medium, i.e., the single-mode fiber (SMF). The technique ensures rapid reduction of erbium gain depletion, Brillouin gain saturation, and Brillouin threshold of the SMF thereby leading to the generation of higher number Brillouin Stokes lines. By utilizing only -8.5 dBm of the BP signal power, the proposed laser generates 54 Brillouin Stokes lines at BP signal wavelength of 1601.7 nm and 33 mW of the 1480-nm laser pump power. The generated channels are rigidly separated by 0.089 nm thereby becoming an attractive candidate to support the dense wavelength division multiplexing optical communication systems. © 2009-2012 IEEE.

Sahari J.,University Putra Malaysia | Sapuan S.M.,University Putra Malaysia | Zainudin E.S.,University Putra Malaysia | Maleque M.A.,International Islamic University Malaysia
Materials and Design | Year: 2013

The aim of this paper is to study the effect of fibre content on mechanical properties, water absorption behaviour and thermal properties of sugar palm fibre (SPF) reinforced plasticized sugar palm starch (SPF/SPS) biocomposites. The biocomposites were prepared with different amounts of fibres (i.e. 10%, 20% and 30% by weight percent) by using glycerol as plasticizer for the starch. The mechanical properties of plasticized SPS improved with the incorporation of fibres. Fibre loading also increased the thermal stability of the biocomposite in this investigation. Water uptake and moisture content of SPF/SPS biocomposites decreased with the incorporation of fibres, which is due to better interfacial bonding between the matrix and fibres as well as the hindrance to absorption caused by the fibres. Fractographic studies through scanning electron microscopy showed homogeneous distribution of fibres and matrix with good adhesion which play an important role in improving the mechanical properties of biocomposites. © 2013 Elsevier Ltd.

Sahari J.,University Putra Malaysia | Sapuan S.M.,University Putra Malaysia | Zainudin E.S.,University Putra Malaysia | Maleque M.A.,International Islamic University Malaysia
Carbohydrate Polymers | Year: 2013

In recent years, increasing environmental concerns focused greater attention on the development of biodegradable materials. A thermoplastic starch derived from bioresources, sugar palm tree was successfully developed in the presence of biodegradable glycerol as a plasticizer. Sugar palm starch (SPS) was added with 15-40 w/w% of glycerol to prepare workable bioplastics and coded as SPS/G15, SPS/G20, SPS/G30 and SPS/G40. The samples were characterized for thermal properties, mechanical properties and moisture absorption on exposure to humidity were evaluated. Morphological studies through scanning electron microscopy (SEM) were used to explain the observed mechanical properties. Generally, the addition of glycerol decrease the transition temperature of plasticized SPS. The mechanical properties of plasticized SPS increase with the increasing of glycerol but up to 30 w/w%. Meanwhile, the water absorption of plasticized SPS decrease with increasing of glycerol. © 2012 Elsevier Ltd.

Al-Mansoori M.H.,Sohar University | Mahdi M.A.,University Putra Malaysia
Optics Express | Year: 2011

We demonstrate a widely tunable L-band multiwavelength Brillouin-erbium fiber laser utilizing a nonlinear amplified fiber loop mirror filter (AFLMF). By manipulating polarization controllers placed in the fiber loop, the erbium peak gain spectrum is able to be shifted. The nonlinear AFLMF induces wavelength-dependent cavity loss and serves as an amplitude equalizer. In addition, it provides flexibility on controlling the amount of light reflected and transmitted into and out of the laser's cavity. By utilizing 100 mW 1480 nm pump and 1.1 mW Brillouin pump power, an average of 24 stable output channels are generated by the proposed structure that could all be tuned over the whole L-band window from 1570 nm to 1610 nm. © 2011 Optical Society of America.

Sonee Shargh R.,University Putra Malaysia | Al-Mansoori M.H.,Sohar University | Anas S.B.A.,University Putra Malaysia | Sahbudin R.K.Z.,University Putra Malaysia | Mahdi M.A.,University Putra Malaysia
Laser Physics Letters | Year: 2011

We propose a simple Brillouin-Raman multichannel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels. © 2011 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.

Abd Rahman Z.,University Putra Malaysia | Hitam S.,University Putra Malaysia | Al-Mansoori M.H.,Sohar University | Abas A.F.,University Putra Malaysia | Mahdi M.A.,University Putra Malaysia
Optics Express | Year: 2011

A multiwavelength widely tunable Brillouin optical comb with an enhanced reverse-S-shaped feedback coupling assisted by out-of-cavity optical amplifier is demonstrated. The enhancement is done by locating the amplifier and the Brillouin pump into the reverse-S-shaped fiber section. The oscillating modes in the cavity are directly influenced solely by the Brillouin gain. A wide tuning range of 45 nm is obtained that is only limited by the erbium amplification bandwidth. An average of eleven laser lines that can be tuned to over 45 nm wavelengths is obtained at 40% optimum output coupling ratio. © 2011 Optical Society of America.

Mohammad N.,International Islamic University Malaysia | Alam Md.Z.,International Islamic University Malaysia | Kabbashi N.A.,International Islamic University Malaysia | Ahsan A.,University Putra Malaysia
Resources, Conservation and Recycling | Year: 2012

Palm oil production is a major agricultural industry in Malaysia, in which palm oil mill effluent (POME) and oil palm empty fruit bunch (EFB) are considered as major waste products from the palm oil industry. These waste products create an environmental hazard and entail high disposal costs every year. Composting is a biologically based process which is practiced to stabilize the organic matter for soil amendment (producing compost) and to protect the environment from the detrimental effects of these waste products. This study reviews the composting process of EFB and POME as a single substrate and/or their mixture by using potential filamentous fungi that are especially lignocellulolytic and antibiotic (in a matured stage) in nature within several effective parameters, for example, C/N ratio, moisture content, pH, temperature, etc. Several studies record the mature composting process as being 60 days. In most cases, temperature and moisture content was maintained up to 70°C and 60-75%, respectively. In addition, this study reviews EFB and POME with their constituents for an efficient composting process. © 2011 Elsevier B.V. All rights reserved.

Gomes C.,University Putra Malaysia | Diego A.G.,Electric Research Institute of Mexico
Safety Science | Year: 2011

This paper provides comprehensive analysis on the lightning protection scenarios in 48 communication and broadcasting towers situated in similar isokeraunic contours in Sri Lanka at 79°-81° East and 5°-10° North. The investigation has been conducted to study the hazardous environment created on the tower and in the neighbourhood in the event of a lightning strike to the tower. The results show that a direct strike to an antenna structure in a metallic tower is rare irrespective of the presence of an air-termination or a down conductor. However, side flashing or arcing to antenna structures is highly possible once the air-termination and/or down conductor is installed and attempts are made to insulate the system from the tower. The outcome also shows that equipotential bonding of the grounding system, a distributed grounding network including a ring conductor and a suitable system of surge protective devices play a much vital role in lightning protection of equipment and safety of people compared to the effects of simply achieving a low grounding resistance. However, in the absence of such integrated, distributed and equipotentialized grounding system, a high value of ground resistance will sharply increase the possibility of accidents and damage. Considering the observations of the investigations into account we have designed a concrete embedded grounding system for tower sites at problematic locations. Finally, the scenarios for safety management at telecommunication tower sites have been discussed. © 2011 Elsevier Ltd.

Salih M.A.,University Putra Malaysia | Salih M.A.,Foundation of Technical Education | Abang Ali A.A.,University Putra Malaysia | Farzadnia N.,University Putra Malaysia
Construction and Building Materials | Year: 2014

This study delineates activation of palm oil fuel ash (POFA) by a combination of sodium silicate and sodium hydroxide at 60 °C to be used as a geopolymer binder. Qualitative observations as well as compressive strength were recorded to assess the viability of POFA utilization. Also, XRD, SEM/EDX, DSC, FTIR tests were conducted to investigate underlying mechanisms of geopolymerization. The post-test observations revealed that activation of POFA is applicable and compressive strength of up to 32.48 MPa at the age of 28 days was achieved. Chemical tests indicated that formation of calcium silicate hydrate was the dominant cause of geopolymerization. © 2014 Elsevier Ltd. All rights reserved.

Cholan N.A.,University Putra Malaysia | Cholan N.A.,University Tun Hussein Onn Malaysia | Al-Mansoori M.H.,Sohar University | Noor A.S.M.,University Putra Malaysia | And 2 more authors.
Optics Express | Year: 2013

A cost effective method of generating multi-wavelength based on the cascaded four wave mixing effect is experimentally demonstrated. The proposed scheme is free from external tunable laser sources and pump modulators, resulting from the use of a broadened linewidth tunable dual wavelength erbium-doped fiber laser as intracavity pump. In this configuration, the number of four wave mixing cascades becomes larger in tandem with the increment of erbium-doped fiber amplifier output power. When its output power is set at 20.57 dBm, six waves having optical signal to noise ratio larger than 10 dB are generated. The six waves are stable with peak power fluctuations less than 1 dB within 30 minutes period and tunable with wavelength spacing ranging from 1.03 nm to 11.31 nm. © 2013 Optical Society of America\e.

Kura A.U.,Institute of Bioscience | Ali S.H.H.A.,Institute of Bioscience | Hussein M.Z.,Institute of Advanced Technology | Fakurazi S.,Institute of Bioscience | And 2 more authors.
International Journal of Nanomedicine | Year: 2013

A new layered organic-inorganic nanocomposite material with an anti-parkinsonian active compound, L-3-(3,4-dihydroxyphenyl) alanine (levodopa), intercalated into the inorganic interlayers of a Zn/Al-layered double hydroxide (LDH) was synthesized using a direct copre- cipitation method. The resulting nanocomposite was composed of the organic moiety, levodopa, sandwiched between Zn/Al-LDH inorganic interlayers. The basal spacing of the resulting nano-composite was 10.9 Å. The estimated loading of levodopa in the nanocomposite was approximately 16% (w/w). A Fourier transform infrared study showed that the absorption bands of the nanocomposite were characteristic of both levodopa and Zn/Al-LDH, which further confirmed intercalation, and that the intercalated organic moiety in the nanocomposite was more thermally stable than free levodopa. The resulting nanocomposite showed sustained-release properties, so can be used in a controlled-release formulation. Cytotoxicity analysis using an MTT assay also showed increased cell viability of 3T3 cells exposed to the newly synthesized nanocomposite compared with those exposed to pure levodopa after 72 hours of exposure. © 2013 Kura et al, publisher and licensee Dove Medical Press Ltd.

Amid M.,University Putra Malaysia | Shuhaimi M.,University Putra Malaysia | Islam Sarker M.Z.,International Islamic University Malaysia | Abdul Manap M.Y.,University Putra Malaysia
Food Chemistry | Year: 2012

An alcohol/salt-based aqueous two-phase (ATPS) system, as a novel method of purification, was employed to purify serine proteases from mango (Mangifera Indica Cv. Chokanan) peel. The effectiveness of different parameters, such as type and concentration of alcohol (1-propanol, 2-propanol, and ethanol), type of salt (sodium citrate, potassium phosphate, and ammonium sulphate), pH, and NaCl, on the purification and selective separation of serine protease was investigated. Desirable conditions of partition coefficient (K), selectivity (S), purification factor (P), and yield (Y%) of serine protease, using ATPS, were determined. The highest partition coefficient (64.5) and selectivity (343.2) for serine protease purification value were achieved in an ATPS of 16% (w/w) 2-propanaol, 19% (w/w) potassium phosphate, and 5% (w/v) NaCl at pH 7.5. It was demonstrated that serine protease could be recovered with a yield of 96.7% and a purification factor of 11.6. © 2011 Elsevier Ltd. All rights reserved.

Moazami D.,University Putra Malaysia | Behbahani H.,Iran University of Science and Technology | Muniandy R.,University Putra Malaysia
Expert Systems with Applications | Year: 2011

With regard to limits in budget, inevitably, one must choose prioritized projects in pavements rehabilitation and maintenance process. This paper looks into prioritization based upon a model including all effects of important factors like pavement condition index, traffic volume, road width as well as rehabilitation and maintenance cost. Since defining a model that introduces all those factors was difficult, a more advanced modeling named fuzzy logic was referred for the problem of prioritization. Although analytical hierarchy process can be used for decision making process as well, fuzzy modeling lets one have more precise choices for the outcome. Finally with the help of MATLAB software and coded M-files, inference engines such as Product engine, Dienes-Rescher and Lukasiewicz were all tested and the logical favorite separation for this application was found in product inference engine. As a case study some streets located in district No. 6 of Tehran municipality were selected and the favorite mathematical model was executed on those streets. This model was used for prioritizing these 131 sections. © 2010 Elsevier Ltd. All rights reserved.

Iqbal S.Z.,Government College University at Faisalabad | Iqbal S.Z.,University Putra Malaysia | Rabbani T.,Government College University at Faisalabad | Asi M.R.,Nuclear Institute for Agriculture and Biology NIAB | Jinap S.,University Putra Malaysia
Food Chemistry | Year: 2014

Aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEN) were analysed in 237 breakfast cereal samples collected from central areas of Punjab, Pakistan. According to the results, 41% of the samples were found contaminated with AFs, out of which 16% and 8% samples were found to be above the European Union (EU) maximum content for AFB1 and total AFs, respectively. About 48% samples were found contaminated with OTA and 30% samples were found to be above the EU maximum content. The results have shown that 53% samples of breakfast cereals were found contaminated with ZEN and 8% samples were found to be above the permissible limit of EU. The highest mean level of AFB1 and total AFs were found in semolina i.e. 3.60 and 4.55 μg/kg, respectively. Similarly, semolina was the highest contaminated breakfast cereal for OTA (3.90 μg/kg), while cornflakes (brand B) was found highest contaminated with ZEN (13.45 μg/kg). © 2014 Elsevier Ltd. All rights reserved.

Natrah F.M.I.,University Putra Malaysia | Bossier P.,Ghent University | Sorgeloos P.,Ghent University | Yusoff F.M.,University Putra Malaysia | Defoirdt T.,Ghent University
Reviews in Aquaculture | Year: 2014

Knowledge on the importance of associations between bacteria and microalgae in aquatic ecosystems is rather limited at the moment, mostly due to a lack of studies at the molecular and biochemical level of microorganisms. This paper discusses the current knowledge on microalgae-bacteria interactions and their potential impacts on the productivity, efficiency and sustainability of aquaculture. Current findings suggest that the interactions are complex and specific. The release of stimulatory products by bacteria that enhance the growth of microalgae, and vice versa, indicates the existence of mutualistic relations. Other factors, such as signalling between bacteria and microalgae, may also play an important role. Although these interactions may be of significant importance, to date, only a few findings have been reported on the use of consortia consisting of microalgae and bacteria for practical purposes. Interestingly, these results pointed out that a combination of microalgae and bacteria is often better than using either of them alone. Further research is needed to obtain a thorough understanding of the mechanisms behind the interactions between these microorganisms, including the identification of active compounds. This knowledge will enable the selection of appropriate consortia for different applications in aquaculture, including disease control and high and sustainable production of feed. © 2013 Wiley Publishing Asia Pty Ltd.

Iqbal S.Z.,Government College University at Faisalabad | Iqbal S.Z.,University Putra Malaysia | Nisar S.,Government College University at Faisalabad | Asi M.R.,Nuclear Institute for Agriculture and Biology NIAB | Jinap S.,University Putra Malaysia
Food Control | Year: 2014

Aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEN) were analyzed in 115 chicken meat and 80 eggs samples, collected from central areas of Punjab, Pakistan. The study was carried out using reverse phase HPLC, equipped with fluorescence detector. The results revealed that 35% samples of chicken and 28% samples of eggs were found contaminated with AFs, and maximum level of AFB1 and total AFs was found in the liver part of chicken (layer) 7.86 and 8.01μg/kg, respectively. Furthermore, 41% samples of chicken and 35% sample of eggs were found contaminated with OTA and maximum level 4.70μg/kg was found in the liver part of chicken meat. However, 52% samples of meat and 32% samples of eggs were found contaminated with ZEN and maximum level 5.10μg/kg was found in the liver part of chicken meat. The occurrence and incidence of AFs, OTA and ZEN in chicken meat and eggs are alarming and it may produce health hazards and urged the need of continuous monitoring for these toxins in chicken meat and eggs. © 2014 Elsevier Ltd.

Banerjee S.,University Putra Malaysia | Mukhopadhyay S.,University of Calgary | Rondoni L.,Polytechnic University of Turin | Rondoni L.,National Institute of Nuclear Physics, Italy
Optics and Lasers in Engineering | Year: 2012

A new technique of transmitting encrypted combinations of gray scaled and chromatic images using chaotic lasers derived from MaxwellBlochs equations has been proposed. This novel scheme utilizes the general method of solution of a set of linear equations to transmit similar sized heterogeneous images which are a combination of monochrome and chromatic images. The chaos encrypted gray scaled images are concatenated along the three color planes resulting in color images. These are then transmitted over a secure channel along with a cover image which is an iris scan. The entire cryptology is augmented with an iris-based authentication scheme. The secret messages are retrieved once the authentication is successful. The objective of our work is briefly outlined as (a) the biometric information is the iris which is encrypted before transmission, (b) the iris is used for personal identification and verifying for message integrity, (c) the information is transmitted securely which are colored images resulting from a combination of gray images, (d) each of the images transmitted are encrypted through chaos based cryptography, (e) these encrypted multiple images are then coupled with the iris through linear combination of images before being communicated over the network. The several layers of encryption together with the ergodicity and randomness of chaos render enough confusion and diffusion properties which guarantee a fool-proof approach in achieving secure communication as demonstrated by exhaustive statistical methods. The result is vital from the perspective of opening a fundamental new dimension in multiplexing and simultaneous transmission of several monochromatic and chromatic images along with biometry based authentication and cryptography. © 2012 Elsevier Ltd. All rights reserved.

Iqbal S.Z.,Government College University at Faisalabad | Iqbal S.Z.,University Putra Malaysia | Asi M.R.,Nuclear Institute for Agriculture and Biology NIAB | Jinap S.,University Putra Malaysia
Food Control | Year: 2013

Total 221 samples of milk and milk products were collected during winter (November 2011-February 2012) and 212 samples were collected during summer (May-August 2012) from central areas of Punjab, Pakistan. The samples were analyzed for the presence of aflatoxin M1 (AFM1) with a validated HPLC method equipped with florescence detector. The results revealed that from winter season almost 45% samples of milk and milk products were found to be contaminated with AFM1 i.e. 40% of raw milk, 51% of UHT milk, 37% of yogurt, 60% of butter and 43% of ice cream samples and 27, 24, 25, 34 and 17% of samples were found above the recommended limit for AFM1, respectively. However, from summer season 32% samples of milk and milk products were found to be contaminated i.e. 36% of raw milk, 31% of UHT milk, 29% of yogurt, 40% of butter and 24% of ice cream and 23, 23, 18, 20 and 5% of samples were found above the permissible limit for AFM1, respectively. The levels of contamination in winter milk and milk product samples were significantly higher (α≤0.05) than in summer season. The occurrence of AFM1 in milk and milk products were higher, demanding to implement strict regulations and also urged the need for continuous monitoring of milk and milk products in order to minimize the health hazards. © 2013 Elsevier Ltd.

El-Shekeil Y.A.,Harbin Institute of Technology | Sapuan S.M.,Harbin Institute of Technology | Abdan K.,University Putra Malaysia | Zainudin E.S.,University Putra Malaysia
Materials and Design | Year: 2012

The aim of this paper is to study the influence of fiber content on mechanical (i.e. tensile, flexural, impact, hardness and abrasion resistance) and thermal (i.e. TGA) properties of Kenaf bast fiber reinforced thermoplastic polyurethane (TPU) composites. The composite was prepared by melt-mixing method, followed by compression molding process. Different fiber loadings were prepared; namely, 20%, 30%, 40%, and 50% weight percent. A 30% fiber loading exhibited the best tensile strength, while modulus increased with increase of fiber content, and strain deteriorated with increase of fiber content. Flexural strength and modulus increased with increase of fiber loading. Increase of fiber loading resulted in decline in impact strength. Hardness increased by addition of 30% fiber content. Abrasion resistant decreased with increase of fiber loading. Fiber loading decreased thermal stability of the composite. © 2012 Elsevier Ltd.

Taghvaee M.H.,University Putra Malaysia | Radzi M.A.M.,University Putra Malaysia | Moosavain S.M.,Islamic Azad University at Shahrood | Hizam H.,University Putra Malaysia | Hamiruce Marhaban M.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

Photovoltaic (PV) is a fast growing segment among renewable energy (RE) systems, whose development is owed to depleting fossil fuel and climate-changing environmental pollution. PV power output capacity, however, is still low and the associated costs still high, so efforts continue to develop PV converter and its controller, aiming for higher power-extracting efficiency and cost effectiveness. Different algorithms have been proposed for Maximum Power Point Tracking (MPPT). Since the choice of right converter for different application has an important influence in the optimum performance of the photovoltaic system, this paper reviews the state-of-the-art in research works on non-isolated DC-DC buck, boost, buck-boost, Cúk and SEPIC converters and their characteristics, to find a solution best suiting an application with Maximum Power Point Tracking. Review shows that there is a limitation in the system's performance according to the type of converter used. In can be concluded that the best selection of DC-DC converter which is really suitable and applicable in the PV system is the buck-boost DC-DC converter since it is capable of achieving optimal operation regardless of the load value with negotiable performance efficiency and price issue. © 2012 Elsevier Ltd.

Saion E.,University Putra Malaysia | Gharibshahi E.,University Putra Malaysia | Naghavi K.,Islamic Azad University at Kermān
International Journal of Molecular Sciences | Year: 2013

Size-controlled and monodispersed silver nanoparticles were synthesized from an aqueous solution containing silver nitrate as a metal precursor, polyvinyl alcohol as a capping agent, isopropyl alcohol as hydrogen and hydroxyl radical scavengers, and deionized water as a solvent with a simple radiolytic method. The average particle size decreased with an increase in dose due to the domination of nucleation over ion association in the formation of the nanoparticles by gamma reduction. The silver nanoparticles exhibit a very sharp and strong absorption spectrum with the absorption maximum λmax blue shifting with an increased dose, owing to a decrease in particle size. The absorption spectra of silver nanoparticles of various particle sizes were also calculated using a quantum physics treatment and an agreement was obtained with the experimental absorption data. The results suggest that the absorption spectrum of silver nanoparticles possibly derived from the intra-band excitations of conduction electrons from the lowest energy state (n = 5, l = 0) to higher energy states (n ≥ 6; Δl = 0, ±1; Δs = 0, ±1), allowed by the quantum numbers principle. This demonstrates that the absorption phenomenon of metal nanoparticles based on a quantum physics description could be exploited to be added into the fundamentals of metal nanoparticles and the related fields of nanoscience and nanotechnology. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Kumar R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia | Rashid S.A.,University Putra Malaysia | Ahmed A.A.,King Fahd University of Petroleum and Minerals
Desalination | Year: 2013

Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes. © 2013 Elsevier B.V.

Azadi M.,Islamic Azad University at Qazvin | Pourakbar S.,University Putra Malaysia | Kashfi A.,Islamic Azad University at Qazvin
Tunnelling and Underground Space Technology | Year: 2013

Currently with the spread of tunnel constructions in cities, the proximity of other structures being built close to these tunnels have now become an important subject. Studying the rate of settlement of structures built in the vicinity of these tunnels could be an importance as well. The distance between tunnels and buildings is an important factor which can also be taken to account. Considering some of the parameters in place, favorable results can be achieved in having tunnels and other structures in the close proximity of each other.In this paper, the settlement of structures with different scenarios has been studied. The proximity of structures and their orientation in comparison with the location of the tunnels has also been a part of this study. Through the Finite Element Method (FEM), and with the use of Neural Network (NN), a various settlement situations have been studied. Using NN on the analysis of the FEM outcome and consideration of the vertical and horizontal distances between the tunnels and constructions with the number of their stories and the diameter of tunnel, relation between the settlements of constructions in any given direction will be immerge. In the study of this matter, the use of methods such as NN and genetic algorithms has not been reported. Using NN to evaluate the results can help to optimize the construction and implementation of underground structures. © 2013 Elsevier Ltd.

Moradi Golsheikh A.,University of Malaya | Huang N.M.,University of Malaya | Lim H.N.,University Putra Malaysia | Zakaria R.,University of Malaya | Yin C.-Y.,Murdoch University
Carbon | Year: 2013

Silver-nanoparticles-decorated reduced graphene oxide (rGO) was electrodeposited on indium tin oxide (ITO) by a cyclic voltammetry method. The results of X-ray diffraction, Fourier-transform infrared transmission spectroscopy and Raman spectroscopy confirmed the simultaneous formation of cubic phase silver nanoparticles and reduction of GO through the electrodeposition process. Field emission scanning electron microscope images showed a uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution on the RGO sheets, which could only be achieved using silver ammonia complex instead of silver nitrate as precursor. The composite deposited on ITO exhibited notable electrocatalytic activity for the reduction of H2O2, leading to an enzymeless electrochemical sensor with a fast amperometric response time less than 2 s. The corresponding calibration curve of the current response showed a linear detection range of 0.1-100 mM (R2 = 0.9992) while the limit of detection was estimated to be 5 μM. © 2013 Elsevier Ltd. All rights reserved.

Dutse S.W.,University Putra Malaysia | Dutse S.W.,UK Defence Science and Technology Laboratory | Yusof N.A.,University Putra Malaysia
Sensors | Year: 2011

Microfluidics-based lab-on-chip (LOC) systems are an active research area that is revolutionising high-throughput sequencing for the fast, sensitive and accurate detection of a variety of pathogens. LOCs also serve as portable diagnostic tools. The devices provide optimum control of nanolitre volumes of fluids and integrate various bioassay operations that allow the devices to rapidly sense pathogenic threat agents for environmental monitoring. LOC systems, such as microfluidic biochips, offer advantages compared to conventional identification procedures that are tedious, expensive and time consuming. This paper aims to provide a broad overview of the need for devices that are easy to operate, sensitive, fast, portable and sufficiently reliable to be used as complementary tools for the control of pathogenic agents that damage the environment. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Neshat A.,University Putra Malaysia | Pradhan B.,University Putra Malaysia | Pirasteh S.,University of Waterloo | Shafri H.Z.M.,University Putra Malaysia
Environmental Earth Sciences | Year: 2014

Groundwater contamination from intensive fertilizer application affects conservation areas in a plain. The DRASTIC model can be applied in the evaluation of groundwater vulnerability to such pollution. The main purpose of using the DRASTIC model is to map groundwater susceptibility to pollution in different areas. However, this method has been used in various areas without modification, thereby disregarding the effects of pollution types and their characteristics. Thus, this technique must be standardized and be approved for applications in aquifers and particular types of pollution. In this study, the potential for the more accurate assessment of vulnerability to pollution is achieved by correcting the rates of the DRASTIC parameters. The new rates were calculated by identifying the relationships among the parameters with respect to the nitrate concentration in groundwater. The methodology was implemented in the Kerman plain in the southeastern region of Iran. The nitrate concentration in water from underground wells was tested and analyzed in 27 different locations. The measured nitrate concentrations were used to associate and correlate the pollution in the aquifer to the DRASTIC index. The Wilcoxon rank-sum nonparametric statistical test was applied to determine the relationship between the index and the measured pollution in Kerman plain. Also, the weights of the DRASTIC parameters were modified through the sensitivity analysis. Subsequently, the rates and weights were computed. The results of the study revealed that the modified DRASTIC model performs more efficiently than the traditional method for nonpoint source pollution, particularly in agricultural areas. The regression coefficients showed that the relationship between the vulnerability index and the nitrate concentration was 82 % after modification and 44 % before modification. This comparison indicated that the results of the modified DRASTIC of this region are better than those of the original method. © 2013 Springer-Verlag Berlin Heidelberg.

Alang Ahmad S.A.,University of Sheffield | Alang Ahmad S.A.,University Putra Malaysia | Wong L.S.,University of Manchester | Ul-Haq E.,University of Sheffield | And 3 more authors.
Journal of the American Chemical Society | Year: 2011

An approach to the integration of nanolithography with synthetic chemical methodology is described, in which near-field optical techniques are used to selectively deprotect films formed by the adsorption of aminosilanes protected by modified 2-nitrophenylethoxycarbonyl (NPEOC) groups. The NPEOC groups are functionalized at the m- or p-position with either a tetraethyleneglycol or a heptaethylene glycol adduct. We describe the synthesis of these bioresistant aminosilanes and the characterization of the resulting photoreactive films. Photodeprotection by exposure to UV light (λ = 325 nm) yielded the amine with high efficiency, at a similar rate for all four adsorbates, and was complete after an exposure of 2.24 J cm-2. Following photodeprotection, derivatization by trifluoroacetic anhydride was carried out with high efficiency. Micropatterned samples, formed using a mask, were derivatized with aldehyde-functionalized polymer nanoparticles and, following derivatization with biotin, were used to form patterns of avidin-coated polymer particles. Fluorescence microscopy and atomic force microscopy data demonstrated that the intact protecting groups conferred excellent resistance to nonspecific adsorption. Nanometer-scale patterns were created using scanning near-field photolithography and were derivatized with biotin. Subsequent conjugation with avidin-functionalized polymer nanoparticles yielded clear fluorescence images that indicated dense attachment to the nanostructures and excellent protein resistance on the surrounding surface. These simple photocleavable protecting group strategies, combined with the use of near-field exposure, offer excellent prospects for the control of surface reactivity at nanometer resolution in biological systems and offer promise for integrating the top-down and bottom-up molecular fabrication paradigms. © 2011 American Chemical Society.

Banerjee M.,Indian Institute of Technology Kanpur | Banerjee S.,Polytechnic University of Turin | Banerjee S.,University Putra Malaysia
Mathematical Biosciences | Year: 2012

In this paper we consider a modified spatiotemporal ecological system originating from the temporal Holling-Tanner model, by incorporating diffusion terms. The original ODE system is studied for the stability of coexisting homogeneous steady-states. The modified PDE system is investigated in detail with both numerical and analytical approaches. Both the Turing and non-Turing patterns are examined for some fixed parametric values and some interesting results have been obtained for the prey and predator populations. Numerical simulation shows that either prey or predator population do not converge to any stationary state at any future time when parameter values are taken in the Turing-Hopf domain. Prey and predator populations exhibit spatiotemporal chaos resulting from temporal oscillation of both the population and spatial instability. With help of numerical simulations we have shown that Turing-Hopf bifurcation leads to onset of spatio-temporal chaos when predator's diffusivity is much higher compared to prey population. Our investigation reveals the fact that Hopf-bifurcation is essential for the onset of spatiotemporal chaos. © 2011 Elsevier Inc.

Ab Kadir M.Z.A.,University Putra Malaysia | Cotton I.,University of Manchester
International Journal of Electrical Power and Energy Systems | Year: 2010

Any insulation coordination study must accurately (or as accurately as possible) express the type and magnitude of all overvoltages on the power system. If these overvoltages are higher than the rating of the equipment, they will result in damage to that equipment. This paper presents the application of the insulator coordination gap models and the effect of line design to the line performance in terms of backflashover rate. The models which are ranging from as simple as voltage controlled switch to as detail as leader progression model will carefully be evaluated. Sensitivity analyses on the effect of line designs such as variation in footing resistance, height of tower/conductor, tower surge impedance and soil resistivity will also be carried out in determining the backflashover rate and the probability of transformer damage by comparing the maximum voltage recorded at the substation entrance with the basic lightning insulation level (BIL). Results will then be compared in finding which model makes the analysis more or less sensitive to any design parameter. © 2009 Elsevier Ltd.

Banerjee S.,University Putra Malaysia | Banerjee M.,Indian Institute of Technology Kanpur
Optics Communications | Year: 2012

The paper reports a detailed analysis of the chaotic dynamics of a theoretical model of a time delayed semi conductor laser. The periodic, quasi-periodic and chaotic nature is investigated with phase-plots, bifurcation analysis and lyapunov exponents. The effect of the system when induced by colored and bounded sine-Wiener noise has been examined extensively. The nature of the noise-induced propagating waves is investigated with the help of wavelet power spectra. It has been observed that the additive noise can suppress the chaotic dynamics of the system. Also the system is more chaotic in the presence of multiplicative noise. Moreover, the additive and multiplicative noise can modulate the output power upto a certain level, with constant input parameters. © 2011 Elsevier B.V. All rights reserved.

Mary A.K.,National Meteorological Center | Gomes C.,University Putra Malaysia
2012 31st International Conference on Lightning Protection, ICLP 2012 | Year: 2012

This paper addresses the lightning safety environment in Uganda that requires urgent and serious attention of the international expert community. We present recent statistics of reported lightning incidents in Uganda which show that the number of injuries and deaths are overwhelmingly high during year 2011 thus the situation can be declared critical. During the five-year period from January 2007 to December 2011, there were 91 reported lightning accidents which accounted for a total number of 150 deaths and 584 cases of personal injuries to which the victims did not succumb. Out of 150 deaths 95 reported in 2011. The actual number in each case may be much higher as many deaths and injuries go unnoticed due to lack of communication between rural communities and government authorities or media sources. The detailed analysis of several incidents reveals that injuries and deaths are basically due to both lack of awareness and absence of proper protection and safety schemes. The decisive factors of the ill-effects of incidents are time of the day, month of the year, part of the country, location of the incident etc. Most of the accidents have occurred either in the afternoon or in the evening. A spread of incidents can be seen throughout the six month period from June to November with June as the month of highest reported deaths. The highest number of incidents has been reported in the Northern Province of the country. Interestingly, the highest number of incidents, deaths and injuries has occurred while the victims were inside permanent structures. After analyzing these incidents a stepwise procedure is proposed to curb such incidents in the future. © 2012 IEEE.

Chandio A.S.,University Putra Malaysia | Lee T.S.,University Putra Malaysia | Mirjat M.S.,University of Sindh
Journal of Hydrology | Year: 2012

A three dimensional finite element model, based on Galerkin weighted residual techniques, is presented for groundwater simulation in the lower Indus Basin, Pakistan. The model was calibrated against field data collected at different agricultural farms located in the Khairpur district. Twenty six observation wells were installed to monitor the groundwater levels for model calibration. The values of the statistical performance parameters adjusted R 2, mean absolute error (MAE), root mean square error (RMSE), Nash-Sutcliffe efficiency or model efficiency (ME), BIAS, and index of agreement (d) showed that the overall model performance for steady and transient groundwater flow is good. The calibrated model was used to assess the impacts of different well pumping rates, well screen lengths, and canals head boundaries on the extent of waterlogging. The model results suggest that well pumping rate is a prominent factor to control waterlogging. An increase in well pumping rate by 25% decreased the water logged area by 16%, while an increase in pumping rate by 50% decreased the water logged area by 25%. The waterlogging in the study area was attributed to the variations in canal water levels. It was further observed that waterlogged area with a watertable depth less than 0.8m is increased by 5.8% when the water level in the Khaipur Feeder East (KFE) canal was increased by 0.6m while the water level at the Rohri canal was kept constant, at the pumping rate of 1728m 3d -1. Similarly, when the water level at the Rohri canal was increased by 1m whilst that at the KFE was kept constant, the area under waterlogging had increased by 10.5%. If water levels in both canals were to be increased simultaneously (0.6m in KFE and 1.0m in Rohri canal) the waterlogged area will increase by 18.1% for the given well discharge. © 2012 Elsevier B.V..

Salmiaton A.,University Putra Malaysia | Garforth A.A.,University of Manchester
Waste Management | Year: 2011

Waste plastics contain a substantial number of valuable chemicals. The wastes from post-consumer as well as from industrial production can be recycled to valuable chemical feedstock, which can be used in refineries and/or petrochemical industries. This chemical recycling process is an ideal approach in recycling the waste for a better environment. Polymer cracking using a laboratory fluidised bed reactor concentrated on the used highly contaminated catalyst, E-Cat 2. Even though E-Cat 2 had low activity due to fewer acid sites, the products yielded were similar with amorphous ASA and were far better than thermal cracking. The high levels of heavy metals, namely nickel and vanadium, deposited during their lifetime as an FCC catalyst, did not greatly affect on the catalyst activity. It was also shown that E-Cat 2 could be used with and without regeneration. Although there was more deactivation when there was no regeneration step, the yield of gases (C2-C7) remained fairly constant. For the first time, these results indicate that "waste" FCC catalyst (E-Cat) is a good candidate for future feedstock recycling of polymer waste. The major benefits of using E-Cat are a low market price, the ability to tolerate reuse and regeneration capacity. © 2011 Elsevier Ltd.

Arifin N.M.,University Putra Malaysia | Nazar R.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Meccanica | Year: 2011

In this paper, a non-isobaric Marangoni boundary layer flow that can be formed along the interface of immiscible nanofluids in surface driven flows due to an imposed temperature gradient, is considered. The solution is determined using a similarity solution for both the momentum and energy equations and assuming developing boundary layer flow along the interface of the immiscible nanofluids. The resulting system of nonlinear ordinary differential equations is solved numerically using the shooting method along with the Runge-Kutta-Fehlberg method. Numerical results are obtained for the interface velocity, the surface temperature gradient as well as the velocity and temperature profiles for some values of the governing parameters, namely the nanoparticle volume fraction ω (0 ≤ ω ≤ 0.2) and the constant exponent β. Three different types of nanoparticles, namely Cu, Al 2O3 and TiO2 are considered by using water-based fluid with Prandtl number Pr = 6.2. It was found that nanoparticles with low thermal conductivity, TiO2, have better enhancement on heat transfer compared to Al2O3 and Cu. The results also indicate that dual solutions exist when β <0.5. The paper complements also the work by Golia and Viviani (Meccanica 21:200-204, 1986) concerning the dual solutions in the case of adverse pressure gradient. © 2010 Springer Science+Business Media B.V.

Rosali H.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Communications in Heat and Mass Transfer | Year: 2012

This paper presents a numerical analysis of a micropolar fluid flow towards a permeable stretching/shrinking sheet in a porous medium. The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations by a similarity transformation, before being solved numerically by a finite-difference scheme known as the Keller-box method. The effects of the governing parameters on the fluid flow and heat transfer characteristics are illustrated graphically. It is found that dual solutions exist for the shrinking case, whereas for the stretching case, the solution is unique. © 2012 Elsevier Ltd.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Journal of Heat and Mass Transfer | Year: 2012

This paper considers the extended Blasius and Sakiadis problems in nanofluids, by considering a uniform free stream parallel to a fixed or moving flat plate, which has more practical significance. It is assumed that the plate moves in the same or opposite direction to the free stream. The resulting system of nonlinear ordinary differential equations is solved numerically for three types of nanoparticles, namely copper (Cu), alumina (Al2O 3), and titania (TiO2) in the water based fluid with Prandtl number Pr = 6.2. The effect of the solid volume fraction parameter of the nanofluids on the heat transfer characteristics is investigated. The results indicate that dual solutions exist when the plate and the free stream move in the opposite directions. © 2011 Elsevier Ltd. All rights reserved.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Journal of Heat and Mass Transfer | Year: 2012

The unsteady boundary layer flow of a nanofluid over a permeable stretching/shrinking sheet is theoretically studied. The governing partial differential equations are transformed into ordinary ones using a similarity transformation, before being solved numerically. The results are obtained for the skin friction coefficient, the local Nusselt number and the local Sherwood number as well as the velocity, temperature and the nanoparticle fraction profiles for some values of the governing parameters, namely, the unsteadiness parameter, the mass suction parameter, the Brownian motion parameter, the thermophoresis parameter, Prandtl number, Lewis number and the stretching/shrinking parameter. It is found that dual solutions exist for both stretching and shrinking cases. The results also indicate that both unsteadiness and mass suction widen the range of the stretching/shrinking parameter for which the solution exists. © 2011 Elsevier Ltd. All rights reserved.

Rashid U.,University of Agriculture at Faisalabad | Rashid U.,Petronas | Anwar F.,University of Agriculture at Faisalabad | Anwar F.,University Putra Malaysia | Knothe G.,U.S. Department of Agriculture
Biomass and Bioenergy | Year: 2011

There is a need to seek non-conventional seed oil sources for biodiesel production due to issues such as supply and availability as well as food versus fuel. In this context, Milo (Thespesia populnea L.) seed oil was investigated for the first time as a potential non-conventional feedstock for preparation of biodiesel. This is also the first report of a biodiesel fuel produced from a feedstock containing cyclic fatty acids as T. populnea contains 8,9-methylene-8-heptadecenoic (malvalic) and smaller amounts of two cyclopropane fatty acids besides greater amounts of linoleic, oleic and palmitic acids. The crude oil extracted from T. populnea seed was transesterified under standard conditions with sodium methoxide as catalyst. Biodiesel derived from T. populnea seed oil exhibited fuel properties of density 880 kg m -3, kinematic viscosity 4.25 mm 2/s; cetane number 59.8; flash point 176 °C; cloud point 9 °C; pour point 8 °C; cold filter plugging point 9 °C; sulfur content 11 mg kg -1; water content 150 mg kg -1; ash content 15 mg kg -1; and acid value as KOH 250 mg kg -1. The oxidative stability of 2.91 h would require the use of antioxidants to meet specifications in standards. Generally, most results compared well with ASTM D6751 and EN 14214 specifications. © 2011 Elsevier Ltd.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Ishak A.,University of Malaya | Pop I.,Technical University of Cluj Napoca
Physica B: Condensed Matter | Year: 2011

The steady flow of an incompressible viscous fluid due to a rotating disk in a nanofluid is studied. The transformed boundary layer equations are solved numerically by a finite difference scheme, namely the Keller-box method. Numerical results for the flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction parameter φ and suction/injection parameter h0. Two models for the effective thermal conductivity of the nanofluid, namely the MaxwellGarnett model and the Patel model, are considered. It is found that for the Patel model, the heat transfer rate at the surface increases for both suction and injection, whereas different behaviors are observed for the MaxwellGarnett model, i.e. increasing the values of φ leads to a decrease in the heat transfer rate at the surface for suction, but increases for injection. The results of this study can be used in the design of an effective cooling system for electronic components to help ensure effective and safe operational conditions. © 2011 Elsevier B.V. All rights reserved.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Nanoscale Research Letters | Year: 2011

An analysis is carried out to study the steady two-dimensional stagnation-point flow of a nanofluid over a stretching/shrinking sheet in its own plane. The stretching/shrinking velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point. The similarity equations are solved numerically for three types of nanoparticles, namely copper, alumina, and titania in the water-based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, Nusselt number, and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction ø on the fluid flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2011 Bachok et al; licensee Springer.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2010 Elsevier B.V.

Khalil H.P.S.A.,Universiti Sains Malaysia | Aprilia N.A.S.,Universiti Sains Malaysia | Aprilia N.A.S.,University of Syiah Kuala | Bhat A.H.,Petronas University of Technology | And 3 more authors.
Renewable and Sustainable Energy Reviews | Year: 2013

This review deals with the study of Jatropha biomass as renewable materials for biocomposites and its applications. Jatropha curcas is a multipurpose plant with many attributes and considerable potential. Jatropha plant is cultivated worldwide but it has specific cultivation area in Central and South America, Africa, and South Asia. The Jatropha plant produces many useful products, especially the seed from which oil can be extracted. Extracted oil has similar properties to palm oil and possible to obtain many products after processing. As biomass, Jatropha plant can used as a reinforcement in biocomposite development. Jatropha contain high amount of carbon especially in seed/husk, fruit shell and seed cake and can be used as filler in composite fabrication in the form of carbon black and activated carbon. In this review, we will discuss the distribution of Jatropha around the globe, chemical composition of various parts and extracts of Jatropha and their mechanical and physical properties. We will also cover the use of Jatropha biomass in various technical and biocomposite applications. With the development of green technology, Jatropha latex can be reduced to nanoparticle size. The chemical and physical properties of Jatropha contribute to its applications in food and non-food Products. © 2013 Elsevier Ltd. All rights reserved.

Nourani V.,University of Tabriz | Pradhan B.,University Putra Malaysia | Ghaffari H.,Islamic Azad University at Mahābād | Sharifi S.S.,University of Tabriz
Natural Hazards | Year: 2014

Without a doubt, landslide is one of the most disastrous natural hazards and landslide susceptibility maps (LSMs) in regional scale are the useful guide to future development planning. Therefore, the importance of generating LSMs through different methods is popular in the international literature. The goal of this study was to evaluate the susceptibility of the occurrence of landslides in Zonouz Plain, located in North-West of Iran. For this purpose, a landslide inventory map was constructed using field survey, air photo/satellite image interpretation, and literature search for historical landslide records. Then, seven landslide-conditioning factors such as lithology, slope, aspect, elevation, land cover, distance to stream, and distance to road were utilized for generation LSMs by various models: frequency ratio (FR), logistic regression (LR), artificial neural network (ANN), and genetic programming (GP) methods in geographic information system (GIS). Finally, total four LSMs were obtained by using these four methods. For verification, the results of LSM analyses were confirmed using the landslide inventory map containing 190 active landslide zones. The validation process showed that the prediction accuracy of LSMs, produced by the FR, LR, ANN, and GP, was 87.57, 89.42, 92.37, and 93.27 %, respectively. The obtained results indicated that the use of GP for generating LSMs provides more accurate prediction in comparison with FR, LR, and ANN. Furthermore; GP model is superior to the ANN model because it can present an explicit formulation instead of weights and biases matrices. © 2013 Springer Science+Business Media Dordrecht.

Al Fugura A.,Al al-Bayt University | Billa L.,University Putra Malaysia | Pradhan B.,University Putra Malaysia
Estuarine, Coastal and Shelf Science | Year: 2011

Coastline identification is important for surveying and mapping reasons. Coastline serves as the basic point of reference and is used on nautical charts for navigation purposes. Its delineation has become crucial and more important in the wake of the many recent earthquakes and tsunamis resulting in complete change and redraw of some shorelines. In a tropical country like Malaysia, presence of cloud cover hinders the application of optical remote sensing data. In this study a semi-automated technique and procedures are presented for shoreline delineation from RADARSAT-1 image. A scene of RADARSAT-1 satellite image was processed using enhanced filtering technique to identify and extract the shoreline coast of Kuala Terengganu, Malaysia. RADSARSAT image has many advantages over the optical data because of its ability to penetrate cloud cover and its night sensing capabilities. At first, speckles were removed from the image by using Lee sigma filter which was used to reduce random noise and to enhance the image and discriminate the boundary between land and water. The results showed an accurate and improved extraction and delineation of the entire coastline of Kuala Terrenganu. The study demonstrated the reliability of the image averaging filter in reducing random noise over the sea surface especially near the shoreline. It enhanced land-water boundary differentiation, enabling better delineation of the shoreline. Overall, the developed techniques showed the potential of radar imagery for accurate shoreline mapping and will be useful for monitoring shoreline changes during high and low tides as well as shoreline erosion in a tropical country like Malaysia. © 2011 Elsevier Ltd.

Tan J.W.,University Putra Malaysia | Tham C.L.,University Putra Malaysia | Israf D.A.,University Putra Malaysia | Lee S.H.,Seoul National University | Kim M.K.,University Putra Malaysia
Neurochemical Research | Year: 2013

l-Glutamate plays a crucial role in neuronal cell death, which is known to be associated with various neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases. In this study, we investigated the protective effects of biochanin A, a phytoestrogen compound found mainly in Trifolium pratense, against l-glutamate-induced cytotoxicity in a PC12 cell line. Exposure of the cells to 10 mM l-glutamate was found to significantly increase cell viability loss and apoptosis, whereas pretreatment with various concentrations of biochanin A attenuated the cytotoxic effects of l-glutamate. Specifically, the pretreatment led to not only decreases in the release of lactate dehydrogenase, the number of apoptotic cells, and the activity of caspase-3 but also an increase in the total glutathione level in the l-glutamate-treated PC12 cells. These results indicate that biochanin A may be able to exert neuroprotective effects against l-glutamate-induced cytotoxicity. Furthermore, our findings also imply that biochanin A may act as an antiapoptotic agent in order to perform its protective function. © 2012 Springer Science+Business Media New York.

Alipour Moghadam R.,Petronas University of Technology | Yusup S.,Petronas University of Technology | Azlina W.,University Putra Malaysia | Nehzati S.,University Putra Malaysia | Tavasoli A.,University of Tehran
Energy Conversion and Management | Year: 2014

Fuel production from agro-waste has become an interesting alternative for energy generation due to energy policies and greater understanding of the importance of green energy. This research was carried out in a lab-scale gasifier and coconut shell was used as feedstock in the integrated process. In order to acquire the optimum condition of syngas production, the effect of the reaction temperature, equivalence ratio (ER) and steam/biomass (S/B) ratio was investigated. Under the optimized condition, H2 and syngas yield achieved to 83.3 g/kg feedstock and 485.9 g/kg feedstock respectively, while LHV of produced gases achieved to 12.54 MJ/N m3. © 2014 Elsevier Ltd. All rights reserved.

Zainudin M.H.M.,University Putra Malaysia | Hassan M.A.,University Putra Malaysia | Tokura M.,Ajinomoto Co. | Shirai Y.,Kyushu Institute of Technology
Bioresource Technology | Year: 2013

The composting of lignocellulosic oil palm empty fruit bunch (OPEFB) with continuous addition of palm oil mill (POME) anaerobic sludge which contained nutrients and indigenous microbes was studied. In comparison to the conventional OPEFB composting which took 60-90. days, the rapid composting in this study can be completed in 40. days with final C/N ratio of 12.4 and nitrogen (2.5%), phosphorus (1.4%), and potassium (2.8%), respectively. Twenty-seven cellulolytic bacterial strains of which 23 strains were closely related to Bacillus subtilis, Bacillus firmus, Thermobifida fusca, Thermomonospora spp., Cellulomonas sp., Ureibacillus thermosphaericus, Paenibacillus barengoltzii, Paenibacillus campinasensis, Geobacillus thermodenitrificans, Pseudoxanthomonas byssovorax which were known as lignocellulose degrading bacteria and commonly involved in lignocellulose degradation. Four isolated strains related to Exiguobacterium acetylicum and Rhizobium sp., with cellulolytic and hemicellulolytic activities. The rapid composting period achieved in this study can thus be attributed to the naturally occurring cellulolytic and hemicellulolytic strains identified. © 2013 Elsevier Ltd.

Ishak A.,National University of Malaysia | Nazar R.,National University of Malaysia | Bachok N.,University Putra Malaysia | Pop I.,Technical University of Cluj Napoca
Physica A: Statistical Mechanics and its Applications | Year: 2010

The steady magnetohydrodynamic (MHD) mixed convection boundary layer flow of a viscous and electrically conducting fluid near the stagnation-point on a vertical permeable surface is investigated in this study. The velocity of the external flow and the temperature of the plate surface are assumed to vary linearly with the distance from the stagnation-point. The governing partial differential equations are first transformed into ordinary differential equations, before being solved numerically by a finite-difference method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. Both assisting and opposing flows are considered. It is found that dual solutions exist for both cases, and the range of the mixed convection parameter for which the solution exists increases with suction. © 2009 Elsevier B.V. All rights reserved.

Goodarz Naseri M.,University of Malayer | Ara M.H.M.,Kharazmi University | Saion E.B.,University Putra Malaysia | Shaari A.H.,University Putra Malaysia
Journal of Magnetism and Magnetic Materials | Year: 2014

This study investigated the synthesis of magnesium ferrite (MgFe2O4) nanoparticles with cubic symmetry that were prepared by a thermal-treatment method by using a solution that contained poly (vinyl alcohol) (PVA) as a capping agent and Mg and Fe nitrates as alternative sources of metal. Heat treatment was conducted using an electric cylinder furnace in an air atmosphere at temperatures between 673 and 973 K, and magnesium ferrite nanoparticles were produced that had different crystallite sizes ranging from5 to 8 nm. The products were well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), X-ray analysis (EDXA), and Fourier transform infrared spectroscopy (FT-IR). All the samples calcined from 673 to 973 K exhibited super paramagnetic behavior with unpaired electrons spins, which was confirmed by using a vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) spectroscopy. © 2013 Published by Elsevier B.V.

Ab Karim S.,University Putra Malaysia | Chi C.G.-Q.,Washington State University
Journal of Hospitality Marketing and Management | Year: 2010

This article illustrates the food image of France, Italy, and Thailand, countries known for their popular cuisine. An online survey was conducted; the population consisted of members of online travel and food groups from Yahoo.com and MSN.com. A total of 294 individuals responded to the online survey. A series of multiple regressions were conducted to determine (a) the relationship between destinations' food image and travelers' visit intention, and (b) the relationship between information sources and travelers' purchase decisions. The results revealed that in general, Italy had the most favorable food image and the highest potential to be visited in the future. Significant positive relationships were found between food image and visit intentions. The study also confirmed that travelers' purchase decisions were significantly influenced by different types of information sources. Conclusions and implications were drawn based on the research findings. This information would be particularly useful for destinations interested in promoting culinary tourism. © Taylor & Francis Group, LLC.

Jafari Kenari S.A.,University Putra Malaysia | Mashohor S.,University Putra Malaysia
Journal of Petroleum Science and Engineering | Year: 2013

Water saturation is one of the important physical properties of the petroleum reservoir which are usually determined by core analysis. An accurate determination of this parameter is significant to execute a realistic evaluation of hydrocarbon reserves in the formation and also decreasing the economic risk. In this study, a robust technique is proposed to determine an accurate value of this parameter from well log data in un-cored well or at un-cored interval of the same well by combining different types of machine learning techniques. The final results (sub-CM outputs) demonstrated that integrating these techniques using proposed method provides an accurate, fast and cost-effective method for estimating the target value. © 2013 Elsevier B.V.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Transport in Porous Media | Year: 2010

The steady boundary-layer flow near the stagnation point on a vertical flat plate embedded in a fluid-saturated porous medium characterized by an anisotropic permeability is investigated. Using appropriate similarity transformation, the governing system of partial differential equations is transformed into a system of ordinary differential equations. This system is then solved numerically. The features of the flow and the heat transfer characteristics for different values of the governing parameters, namely, the modified mixed convection parameter Λ, and the anisotropy parameter A are analyzed and discussed. It is found that dual solutions exist for both assisting and opposing flows. Moreover, the range of Λ for which the solution exists increases with A. © Springer Science+Business Media B.V.2009.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
Acta Mechanica Sinica/Lixue Xuebao | Year: 2012

An analysis is performed to study the heat transfer characteristics of steady two-dimensional boundary layer flow past a moving permeable flat plate in a nanofluid. The effects of uniform suction and injection on the flow field and heat transfer characteristics are numerically studied by using an implicit finite difference method. It is found that dual solutions exist when the plate and the free stream move in the opposite directions. The results indicate that suction delays the boundary layer separation, while injection accelerates it. © 2012 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Journal of Thermal Sciences | Year: 2010

The steady boundary-layer flow of a nanofluid past a moving semi-infinite flat plate in a uniform free stream is investigated. The plate is assumed to move in the same or opposite directions to the free stream. The resulting system of nonlinear ordinary differential equations is solved numerically using the Keller-box method. Numerical results are obtained for the skin-friction coefficient, the local Nusselt number and the local Sherwood number as well as the velocity, temperature and the nanoparticle volume fraction profiles for some values of the governing parameters, namely, the plate velocity parameter, Prandtl number, Lewis number, the Brownian motion parameter and the thermophoresis parameter. The results indicate that dual solutions exist when the plate and the free stream move in the opposite directions. © 2010 Elsevier Masson SAS. All rights reserved.

Rosali H.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Technical University of Cluj Napoca
International Communications in Heat and Mass Transfer | Year: 2011

The steady stagnation point flow and heat transfer over a shrinking sheet in a porous medium is studied. A similarity transformation is used to reduce the governing system of partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using the Keller-box method. The behavior of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. The results indicate that dual solutions exist for the shrinking case. © 2011 Elsevier Ltd.

Sathyamurthy R.,Hindustan University | Kennady H.J.,Hindustan University | Nagarajan P.K.,Sa Engineering College | Ahsan A.,University Putra Malaysia
Desalination | Year: 2014

This work presents a few important factors that affect the performance of a triangular pyramid solar still. An experimental work has been conducted to find the effect of water depth on the performance of the triangular pyramid solar still. From the present study, it is concluded that the convective and evaporative heat transfer coefficients are important for designing solar distillation systems and the effect of temperature difference between the evaporative and condensing surfaces is also important to optimize the operating temperature range. The condensing area of the solar still is more than that of evaporating area. Thus the experimental results showed that the effect of depth of water in the solar still affects the fresh water production. Nevertheless, outdoor experimental tests were conducted to study the effect of wind speed variations to cool down the glass cover. It was found that increasing the wind speed from 1.5 to 3. m/s and to 4.5. m/s has the effect of increasing the still productivity by 8 and 15.5% respectively. © 2014 Elsevier B.V.

Ab Ghani N.I.,University Putra Malaysia | Merila J.,University of Helsinki
Oikos | Year: 2014

Compensatory growth (CG) is a form of phenotypic plasticity allowing individuals' growth trajectories to rebound after a period of resource limitation, but little is known about the reproductive and cross-generational costs of CG. We studied the potential costs of CG by exposing female nine-spined sticklebacks Pungitius pungitius to 1) high (favourable), 2) low (stressful), and 3) recovery (initially stressful, subsequently favourable) feeding treatments, and quantified the effects of these treatments on female reproductive traits (clutch, egg and yolk size), and on the size of their offspring. The low feeding treatment reduced female size relative to the high and recovery feeding treatments, which produced equally large females. Hence, females from the recovery treatment demonstrated CG and full growth compensation. Feeding treatments had significant effects on clutch, yolk, egg and larval size, also when the effect of female size was controlled for. However, these effects came about mostly because females from the low feeding treatment produced small clutches with large eggs (containing little yolk) and larvae, whereas females from the recovery feeding treatment produced as large clutches, eggs (with similar amounts of yolk) and larvae as females from the high feeding treatment. Yet, structural equation modelling revealed that while a direct effect of female size on offspring size was positive in the low and high feeding treatments, it was negative in the recovery feeding treatment, independently of egg and clutch size. This indicates a cross-generational tradeoff between female and offspring sizes in the recovery feeding treatment. Also the tradeoff between clutch and larval size was more pronounced in recovery than in low or high feeding treatments. Hence, apart from demonstrating that environmental influences experienced by females during their development have the potential to influence their size, fecundity and reproductive traits, the results also provide evidence for complex cross-generational costs of recovery growth. © 2014 The Authors.

Hamedianfar A.,University Putra Malaysia | Shafri H.Z.M.,University Putra Malaysia | Mansor S.,University Putra Malaysia | Ahmad N.,National Space Agency
International Journal of Remote Sensing | Year: 2014

Urbanization is commonly accepted as an important contributor to the growth of man-made structures and as a rapid convertor of natural environments to impervious surfaces. Roofs are one class of impervious surface whose materials can highly influence the quality of urban surface water. In this study, two data sources, WorldView-2 (WV-2) imagery and a combination of WV-2 and lidar data, were utilized to map intra-urban targets, with 13 classes. Images were classified using object-based image analysis. Pixel-based classifications using the support vector machine (SVM) and maximum likelihood (ML) methods were also tested for their abilities to use both lidar data and WV-2 imagery. ML and SVM classifications yielded overall accuracies of 72.46% and 75.69%, respectively. The results of these classifiers exhibited mixed pixels and salt-and-pepper effects. Spectral, spatial, and textural attributes as well as various spectral indices were employed in the object-based classification of WV-2 imagery. Feature classification of WV-2 imagery resulted in 85% overall accuracy. Lidar data were added to WV-2 imagery to assist in the spatial and spectral diversities of urban infrastructures. Classified image made from WV-2 imagery and lidar data achieved 92.84% overall accuracy. Rule-sets of these fused datasets effectively reduced the spectral variation and spatial heterogeneities of intra-urban classes, causing finer boundaries among land-cover classes. Therefore, object-based classification of WV-2 imagery and lidar data efficiently improved detailed characterization of roof types and other urban surface materials. © 2014 Taylor & Francis.

Homayouni S.M.,Islamic Azad University | Tang S.H.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

According to previous researches, automated guided vehicles and quay cranes in container terminals have a high potential synergy. In this paper, a mixed integer programming model is formulated to optimize the coordinated scheduling of cranes and vehicles in container terminals. Objectives of the model are to minimize total traveling time of the vehicles and delays in tasks of cranes. A genetic algorithm is developed to solve the problem in reasonable computational time. The most appropriate control parameters for the proposed genetic algorithm are investigated in a medium size numerical test case. It is shown that balanced crossover and mutation rates have the best performance in finding a near optimal solution for the problem. Then, ten small size test cases are solved to evaluate the performance of the proposed optimization methods. The results show the applicability of the genetic algorithm since it can find near optimal solutions, precisely and accurately. © 2013 Seyed Mahdi Homayouni and Sai Hong Tang.

Akgun A.,Karadeniz Technical University | Kincal C.,Dokuz Eylül University | Pradhan B.,University Putra Malaysia
Environmental Monitoring and Assessment | Year: 2012

In this study, landslide risk assessment for Izmir city (west Turkey) was carried out, and the environmental effects of landslides on further urban development were evaluated using geographical information systems and remote sensing techniques. For this purpose, two different data groups, namely conditioning and triggering data, were produced. With the help of conditioning data such as lithology, slope gradient, slope aspect, distance from roads, distance from faults and distance from drainage lines, a landslide susceptibility model was constructed by using logistic regression modelling approach. The accuracy assessment of the susceptibility map was carried out by the area under curvature (AUC) approach, and a 0.810 AUC value was obtained. This value shows that the map obtained is successful. Due to the fact that the study area is located in an active seismic region, earthquake data were considered as primary triggering factor contributing to landslide occurrence. In addition to this, precipitation data were also taken into account as a secondary triggering factor. Considering the susceptibility data and triggering factors, a landslide hazard index was obtained. Furthermore, using the Aster data, a land-cover map was produced with an overall kappa value of 0.94. From this map, settlement areas were extracted, and these extracted data were assessed as elements at risk in the study area. Next, a vulnerability index was created by using these data. Finally, the hazard index and the vulnerability index were combined, and a landslide risk map for Izmir city was obtained. Based on this final risk map, it was observed that especially south and north parts of the Izmir Bay, where urbanization is dense, are threatened to future landsliding. This result can be used for preliminary land use planning by local governmental authorities. © Springer Science+Business Media B.V. 2011.

Biswajeet P.,Sudan University of Science and Technology | Biswajeet P.,University Putra Malaysia | Saied P.,University Putra Malaysia
Disaster Advances | Year: 2010

Preparation of L and slide susceptibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of L and slides, producing a reliable susceptibility map is not easy. In recent years, various data mining and soft computing techniques are getting popular for the prediction and classification of L and slide susceptibility and hazard mapping. This paper presents a comparative analysis of the prediction capabilities between the neural network and fuzzy logic model for L and slide susceptibility mapping in a geographic information system (GIS) environment. In the first stage, L and slide-related factors such as altitude, slope angle, slope aspect, distance to drainage, distance to road, lithology and normalized difference vegetation index (ndvi) were extracted from topographic and geology and soil maps. Secondly, L and slide locations were identified from the interpretation of aerial photographs, high resolution satellite imageries and extensive field surveys. Then L and slide-susceptibility maps were produced by the application of neural network and fuzzy logic approahc using the aforementioned L and slide related factors. Finally, the results of the analyses were verified using the L and slide location data and compared with the neural network and fuzzy logic models. The validation results showed that the neural network model (accuracy is 88%) is better in prediction than fuzzy logic (accuracy is 84%) models. Results show that "gamma" operator (X = 0.9) showed the best accuracy (84%) while "or" operator showed the worst accuracy (66%).

Harith H.H.,University of New South Wales | Harith H.H.,University Putra Malaysia | Morris M.J.,University of New South Wales | Kavurma M.M.,University of New South Wales
Trends in Endocrinology and Metabolism | Year: 2013

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been extensively studied for its preferential ability to induce apoptosis of cancer cells. Beyond the cytotoxic capacity of TRAIL, new physiological and pathological roles for TRAIL have been identified, and there is now growing evidence supporting its involvement in the development of obesity and diabetes. This review summarizes the most recent findings associating TRAIL with obesity and diabetes in both humans and experimental settings. We also present and discuss some of the reported controversies behind TRAIL signaling and function. Understanding TRAIL mechanism(s) in vivo and its involvement in disease may lead to novel strategies to combat the growing pandemic of obesity and diabetes worldwide. © 2013.

Najigivi A.,Sharif University of Technology | Khaloo A.,Sharif University of Technology | Iraji Zad A.,Sharif University of Technology | Abdul Rashid S.,University Putra Malaysia
Composites Part B: Engineering | Year: 2013

The aim of this study was to assess the effects of two different types of SiO2 nanoparticles (N and M series) with different ratios on the workability and compressive strength of developed binary blended concretes cured in water and lime solution as two different curing media. N and M series SiO2 nanoparticles with an average size of 15 nm were used as obtained from the suppliers. Fresh and hardened concretes incorporating 0.5%, 1.0%, 1.5% and 2.0% of N and 2% of M series nanoparticles with constant water to binder ratio and aggregate content were made and tested. Fresh mixtures were tested for workability and hardened concretes were tested for compressive strength at 7, 28 and 90 days of curing. Fresh concrete test results showed that the workability of binary blends was reduced in the presence of both types of SiO2 nanoparticles. Hardened concrete test results revealed that the optimal replacement level of cement by N series of SiO2 nanoparticles for producing concrete with considerably improved strength was set at 1.0 wt.% after curing in water. However, the ultimate strengths of binary blended concretes were gained at 2.0 wt.% replacement of cement by both series after curing in lime solution. It is concluded that SiO2 nanoparticles play significant roles in mechanical properties of concrete by formation of additional calcium silicate hydrate gel during treatment, which played an important role in raising highly the compressive strength of binary blends. The current study sheds light on the implications of nanotechnology in nano-engineering of concrete. © 2013 Elsevier Ltd. All rights reserved.

Pradhan B.,University Putra Malaysia | Hagemann U.,Sudan University of Science and Technology | Shafapour Tehrany M.,University Putra Malaysia | Prechtel N.,Sudan University of Science and Technology
Computers and Geosciences | Year: 2014

Extraction of the flooded areas from synthetic aperture radar (SAR) and especially TerraSAR-X data is one of the most challenging tasks in the flood management and planning. SAR data due to its high spatial resolution and its capability of all weather conditions makes a proper choice for tropical countries. Texture is considered as an effective factor in distinguishing the classes especially in SAR imagery which records the backscatters that carry information of kind, direction, heterogeneity and relationship of the features. This paper put forward a computer program for texture analysis for high resolution radar data. Texture analysis program is introduced and discussed using the gray-level co-occurrence matrix (GLCM). To demonstrate the ability and correctness of this program, a test subset of TerraSAR-X imagery from Terengganu area, Malaysia was analyzed and pixel-based and object-based classification were attempted. The thematic maps derived by pixel-based method could not achieve acceptable visual interpretation and for that reason no accuracy assessment was performed on them. The overall accuracy achieved by object-based method was 83.63% with kappa coefficient of 0.8. Results on image texture classification showed that the proposed program is capable for texture analysis in TerraSAR-X image and the obtained textural analysis resulted in high classification accuracy. The proposed texture analysis program can be used in many applications such as land use/cover (LULC) mapping, hazard studies and many other applications. © 2013 Elsevier Ltd.

Amirhashchi H.,Islamic Azad University at Mahshahr | Pradhan A.,Hindu Post graduate College | Zainuddin H.,University Putra Malaysia
Research in Astronomy and Astrophysics | Year: 2013

We study the evolution of the dark energy parameter within the scope of a spatially non-flat and isotropic Friedmann-Robertson-Walker model filled with barotropic fluid and bulk viscous stresses. We have obtained cosmological solutions that do not have a Big Rip singularity, and concluded that in both non-interacting and interacting cases the non-flat open Universe crosses the phantom region. We find that during the evolution of the Universe, the equation of state for dark energy ωD changes from ω eff D > -1 to ωeff D < -1, which is consistent with recent observations. © 2013 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd..

Karimi S.,University Putra Malaysia | Tahir P.M.,University Putra Malaysia | Karimi A.,University Putra Malaysia | Karimi A.,University of Tehran | And 2 more authors.
Carbohydrate Polymers | Year: 2014

Cellulosic fibers from kenaf bast were isolated in three distinct stages. Initially raw kenaf bast fibers were subjected to an alkali pulping process. Then pulped fibers undergone a bleaching process and finally both pulped and bleached fibers were separated into their constituent nanoscale cellulosic fibers by mechanical shearing. The influence of each treatment on the chemical composition of fibers was investigated. Moreover morphology, functional groups, crystallinity, and thermal behavior of fiber hierarchy at different stages of purification were studied using scanning and transmission electron microscopies, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Microscopy studies revealed that applied procedures successfully isolated nanoscale cellulosic fibers from both unbleached and bleached pulps. Chemical composition analysis and FTIR spectroscopy showed that lignin and hemicellulose were almost entirely removed by the applied treatments. XRD and TGA analyses demonstrated progressive enhancement of properties in fibers, hierarchically, in going from micro to nano scale. Interestingly no significant evolution was observed between obtained data of characterized ubnleached and bleached nanofibers. © 2013 Elsevier Ltd. All rights reserved.

Tamjidyamcholo A.,University of Malaya | Bin Baba M.S.,University of Malaya | Tamjid H.,University Putra Malaysia | Gholipour R.,University of Tehran
Computers and Education | Year: 2013

Knowledge sharing is an important component of knowledge management systems. Security knowledge sharing substantially reduces risk and investment in information security. Despite the importance of information security, little research based on knowledge sharing has focused on the security profession. Therefore, this study analyses key factors, containing attitude, self-efficacy, trust, norm of reciprocity, and shared language, in respect of the information security workers intention to share knowledge. Information security professionals in virtual communities, including the Information Security Professional Association (ISPA), Information Systems Security Association (ISSA), Society of Information Risk Analysts (SIRA), and LinkedIn security groups, were surveyed to test the proposed research model. Confirmatory factor analysis (CFA) and the structural equation modelling (SEM) technique were used to analyse the data and evaluate the research model. The results showed that the research model fit the data well and the structural model suggests a strong relationship between attitude, trust, and norms of reciprocity to knowledge sharing intention. Hypotheses regarding the influence of self-efficacy and reciprocity, to knowledge sharing attitude were upheld. Shared language did not influence either the attitude or intention to share knowledge. © 2013 Elsevier Ltd. All rights reserved.

Omar N.,National Public Health Laboratory | Bakar J.,University Putra Malaysia | Muhammad K.,University Putra Malaysia
Food Control | Year: 2013

Pacific white shrimp (Litopenaeus vannamei) collected during dry and rainy seasons from three different states in Malaysia were analyzed for nine organochlorine pesticides (OCPs) (α-HCH, β-HCH, γ-HCH, δ-HCH, trans-chlordane, cis-chlordane, p,p'-DDE, p,p'-DDD and p,p'-DDT) using QuEChERS sample preparation method and GC-MS SIM with split/splitless injection mode. The efficiency of combination of primary and secondary amine (PSA) and octadecyl (C18) at 25mg of PSA and 25mg of C18 per mL of shrimp extract as the clean-up sorbent to remove matrix interferences was evaluated. By combining PSA and C18, matrix interferences such as gamma-tocopherol and cholesterol were not able to be eliminated. Good separation and high recoveries which ranged from 90 to 105% with associated RSD<15% were obtained for all OCPs at 3-75ng/g. No significant difference in recoveries due to seasonal variation for studied OCPs, except for α-HCH, β-HCH, δ-HCH and p,p'-DDT were obtained. The limits of detection and quantification ranged from 0.3 to 4.5ng/g and 3 to 15ng/g, respectively. The linearity for matrix matched standard calibrations was >0.99. © 2013 Elsevier Ltd.

Zamri-Saad M.,University Putra Malaysia | Amal M.N.A.,University Putra Malaysia | Siti-Zahrah A.,National Health Research Institute
Journal of Comparative Pathology | Year: 2010

The pathological changes present in 300 red tilapias (Oreochromis spp.) naturally infected by Streptococcus agalactiae are described. The most consistent gross findings were marked congestion of internal organs, particularly the liver, spleen and kidneys. Other features included exophthalmos, softening of the brain and the occasional accumulation of fluid within the abdominal cavity. Microscopical examination confirmed the presence of marked congestion of the liver, spleen and kidneys. The endothelial cells lining major blood vessels of the liver and occasionally the spleen were swollen and vacuolated. There was evidence of vascular thrombosis with infarction of surrounding tissue. Bacterial colonies were noted within and immediately surrounding the affected blood vessels. The meninges were thickened by the infiltration of numerous heterophils. Similar infiltrates of heterophils and lymphocytes were observed in the lamina propria of the intestine. The kidneys were severely congested and haemorrhagic, with extensive interstitial nephritis. © 2010 Elsevier Ltd.

Islam M.S.,University Malaysia Sarawak | Hamdan S.,University Malaysia Sarawak | Talib Z.A.,University Putra Malaysia | Ahmed A.S.,University Malaysia Sarawak | Rahman M.R.,University Malaysia Sarawak
Composites Science and Technology | Year: 2012

In this study, wood polymer nanocomposites (WPNCS) were manufactured from five Malaysian tropical wood species by vacuum-impregnation attended by in situ polymerization using phenol-formaldehyde resin and montmorillomite nanoclay. Percentage weight gain and density of wood polymer nanocomposites depended on wood species. Thermo-mechanical properties of wood samples were investigated by the dynamic mechanical thermal analysis (DMTA) over the temperature range of -100 °C to 200 °C. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases were also determined through DMTA test. Storage modulus (E') of WPNC samples exhibited significant improvement over the temperature range, in both glassy region and rubbery plateau in relation to their corresponding raw wood samples and wood polymer composites (WPCs). Furthermore, damping (loss tan δ) peaks of all wood species were lowered by PF-Nanoclay system treatment, an indication of improved surface interphase of wood. Dynamic Young's modulus (E d) of wood was also calculated using free-free vibration testing. A significant increment was obtained for the PF-Nanoclay impregnated WPNC samples. © 2012 Elsevier Ltd.

Paterson R.R.M.,IBB Institute for Biotechnology And Bioengineering | Sariah M.,University Putra Malaysia | Lima N.,IBB Institute for Biotechnology And Bioengineering
Crop Protection | Year: 2013

Palm oil is a very important commodity. It is added to numerous products and is a biofuel. However, oil palms (OP) are subjected to fungal diseases of which Fusarium wilt and Ganoderma rots are the most important. Considerations of how climate change (CC) affects tropical economic plants are limited and for OP are even fewer. The margin for adapting to higher temperatures and changing humidity is reduced in tropical OP. Land will become increasingly unsuitable for growing OP and the plants will become stressed allowing ingress of fungal diseases. New land will be increasingly suitable where the environmental conditions are less severe than in the tropics. Novel diseases may threaten the crop. Finally, the effect of the major consequences of CC on OP fungal diseases is considered herein with a view to establishing key hypotheses. © 2013 Elsevier Ltd.

Wahi R.,University Putra Malaysia | Wahi R.,University Malaysia Sarawak | Chuah L.A.,University Putra Malaysia | Choong T.S.Y.,University Putra Malaysia | And 2 more authors.
Separation and Purification Technology | Year: 2013

The threat of oil pollution increases with the expansion of oil exploration and production activities, as well as the industrial growth around the world. The study on the treatment of oily wastewater is a critical issue to the environmental protection as oil caused problems to the wastewater treatment facilities. Although oil particles can efficiently be removed by advanced technologies, the treatments are usually expensive and difficult to maintain. Adsorption and coalescence filtration are promising choice of treatment for its simplicity, effectiveness, and feasibility when appropriate sorbent is used. This review discusses the recent papers on the use of natural fibrous sorbent for removal of oil from wastewater, and its current development. With their excellent oil removal properties, environmental friendliness, easy availability, and feasibility, natural fibrous sorbents are an attractive alternative for oily wastewater treatment. © 2013 Elsevier B.V. All rights reserved.

Hoidy W.H.,University Putra Malaysia | Al-Mulla E.A.J.,University of Kufa | Al-Janabi K.W.,University of Baghdad
Journal of Polymers and the Environment | Year: 2010

Poly(l-lactic acid) (PLLA)/poly(caprolactone) (PCL) and two types of organoclay (OMMT) including a fatty amide and ocatdecylamine montmorillonite (FA-MMT and ODA-MMT) were employed to produce polymer nanocomposites by melt blending. Materials were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), elemental analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical properties were also investigated for these nanocomposites. The nanocomposites showed increasing mechanical properties and thermal stability. XRD results indicated that the materials formed nanocomposites. SEM morphology showed that increasing content of OMMT reduced the domain size of phase separated particles. TEM outcomes have confirmed the intercalated type of nanocomposite. Additionally, a solution casting process has been used to prepare these nanocomposites and characterized to compare these results with the above process. © 2010 Springer Science+Business Media, LLC.

Wang F.,University of New South Wales | Reece P.J.,University of New South Wales | Paiman S.,Australian National University | Paiman S.,University Putra Malaysia | And 3 more authors.
Nano Letters | Year: 2011

We report on the observation of nonlinear optical excitation and related photoluminescence from single InP semiconductor nanowires held in suspension using a gradient force optical tweezers. Photoexcitation of free carriers is achieved through absorption of infrared (1.17 eV) photons from the trapping source via a combination of two- and three-photon processes. This was confirmed by power-dependent photoluminescence measurements. Marked differences in spectral features are noted between nonlinear optical excitation and direct excitation and are related to band-filling effects. Direct observation of second harmonic generation in trapped InP nanowires confirms the presence of nonlinear optical processes. © 2011 American Chemical Society.

Mariod A.A.,University Putra Malaysia | Mariod A.A.,Sudan University of Science and Technology | Ibrahim R.M.,University Putra Malaysia | Ismail M.,University Putra Malaysia | Ismail N.,University Putra Malaysia
Food Chemistry | Year: 2010

The antioxidant activities of phenolic rich fractions (PRFs) from crude methanolic extract (CME), and its fractions using ethyl acetate (EAF), hexane (HF) and water (WF) of black mahlab (Monechma ciliatum) and white mahlab (Prunus mahaleb) seedcakes were investigated. The total phenolic compounds were found to be higher in white mahlab than black mahlab seedcakes. The antioxidant activity determined by the DPPH method revealed that black mahlab PRFs had the highest antioxidant activity, compared to white mahlab fractions. The presence of antioxidants in the two mahlab PRFs reduced the oxidation of β-carotene by hydroperoxides from these extracts/fractions. The effect of the two mahlab PRFs on the oxidative stability of corn oil at 70 °C was tested in the dark and compared with butylated hydroxyanisole (BHA). The CME performed better antioxidant activity in inhibiting the formation of both primary and secondary oxidation products. The qualitative and quantitative characterisation of phenolic compounds was carried out by HPLC/DAD. © 2009 Elsevier Ltd. All rights reserved.

Reece P.J.,University of New South Wales | Toe W.J.,University of New South Wales | Wang F.,University of New South Wales | Paiman S.,Australian National University | And 4 more authors.
Nano Letters | Year: 2011

We report on the optical trapping characteristics of InP nanowires with dimensions of 30 (±6) nm in diameter and 2 - 15 μm in length. We describe a method for calibrating the absolute position of individual nanowires relative to the trapping center using synchronous high-speed position sensing and acousto-optic beam switching. Through Brownian dynamics we investigate effects of the laser power and polarization on trap stability, as well as length dependence and the effect of simultaneous trapping multiple nanowires. © 2011 American Chemical Society.

Zare M.,University of Tehran | Pourghasemi H.R.,Tarbiat Modares University | Vafakhah M.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia
Arabian Journal of Geosciences | Year: 2013

Landslide susceptibility and hazard assessments are the most important steps in landslide risk mapping. The main objective of this study was to investigate and compare the results of two artificial neural network (ANN) algorithms, i.e., multilayer perceptron (MLP) and radial basic function (RBF) for spatial prediction of landslide susceptibility in Vaz Watershed, Iran. At first, landslide locations were identified by aerial photographs and field surveys, and a total of 136 landside locations were constructed from various sources. Then the landslide inventory map was randomly split into a training dataset 70 % (95 landslide locations) for training the ANN model and the remaining 30 % (41 landslides locations) was used for validation purpose. Nine landslide conditioning factors such as slope, slope aspect, altitude, land use, lithology, distance from rivers, distance from roads, distance from faults, and rainfall were constructed in geographical information system. In this study, both MLP and RBF algorithms were used in artificial neural network model. The results showed that MLP with Broyden-Fletcher-Goldfarb-Shanno learning algorithm is more efficient than RBF in landslide susceptibility mapping for the study area. Finally the landslide susceptibility maps were validated using the validation data (i.e., 30 % landslide location data that was not used during the model construction) using area under the curve (AUC) method. The success rate curve showed that the area under the curve for RBF and MLP was 0.9085 (90.85 %) and 0.9193 (91.93 %) accuracy, respectively. Similarly, the validation result showed that the area under the curve for MLP and RBF models were 0.881 (88.1 %) and 0.8724 (87.24 %), respectively. The results of this study showed that landslide susceptibility mapping in the Vaz Watershed of Iran using the ANN approach is viable and can be used for land use planning. © 2012 Saudi Society for Geosciences.

Rahim K.A.,University Putra Malaysia | Liwan A.,University Malaysia Sarawak
Energy Policy | Year: 2012

The trends of reserves, production and consumption of oil in Malaysia to meet the ever-increasing demands do not seem to show that oil and gas will be depleted soon, contrary to many reports. Malaysia's net exporter status of oil continues to expand over time for as long as the value of exports is greater than the value of imports. Only in physical quantities of oil that Malaysia's imports exceed exports, but this does not mean that Malaysia will be a net importer by then. Given higher prices of exports, the value of exports outweighs the value of imports. If the current reserves are extracted based on the domestic consumption trend of 1980-2010, Malaysia's reserves will last until 2027 but based on the 1998-2010 trend, the reserves will be depleted by 2035. Malaysia has adopted a four fuel diversification strategy comprising oil, gas, coal and hydro, instead of heavily dependent on oil. Gas has a huge potential for domestic utilization as well as for exports to increase revenues. Malaysia is one of the few countries having many types of renewable energy sources. Malaysia has great potential in biomass utilization as renewable resources mostly from the existing natural forest and planned plantations. © 2012 Elsevier Ltd.

Al-Mulla E.A.J.,University of Kufa | Suhail A.H.,University Putra Malaysia | Aowda S.A.,University of Babylon
Industrial Crops and Products | Year: 2011

Biodegradable polymers, such as poly(lactic acid) (PLA) have attracted a lot of attention in the scientific community recently due to a rapid growth of intensive interest in the global environment for alternatives to petroleum-based polymeric materials. Fatty nitrogen compounds (FNCs), fatty amides (FA), fatty hydroxamic acids (FHA), and carbonyl difatty amides (CDFA), which were synthesized from vegetable oils, were used as one of organic compounds to modify natural clay (sodium montmorillonite). The clay modification was carried out by stirring the clay particles in an aqueous solution of FA, FHA, and CDFA, by which the clay layer thickness increased from 1.23 to 2.61, 2.84 and 3.19 nm, respectively. The modified clay was then used in the preparation of the PLA/epoxidized soybean oil (ESO) blend nanocomposites. They were prepared by incorporating 2% of CDFA-MMT and 3% of both FA-MMT and FHA-MMT. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by solution casting of the modified clay and a PLA/ESO blend at the weight ratio of 80/20, which has the highest elongation at break. The XRD and transmission electron microscopy (TEM) results confirmed the production of nanocomposites. PLA/ESO modified clay nanocomposites show higher thermal stability and significant improvement of mechanical properties in comparison with those of the PLA/ESO blend. The novelty of this study is use of FNCs which reduces the dependence on petroleum-based surfactants. © 2010 Elsevier B.V.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Nazar R.,National University of Malaysia
Meccanica | Year: 2011

The unsteady laminar flow of an incompressible micropolar fluid over a stretching sheet is investigated. The unsteadiness in the flow and temperature fields is caused by the time-dependence of the stretching velocity and the surface temperature. Effects of the unsteadiness parameter, material parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. © 2010 Springer Science+Business Media B.V.

Tohidi E.,Islamic Azad University at Zahedan | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

A new collocation method is developed for solving BVPs which arise from the problems in calculus of variation. These BVPs result from the Euler-Lagrange equations, which are the necessary conditions of the extremums of problems in calculus of variation. The proposed method is based upon the Bernoulli polynomials approximation together with their operational matrix of differentiation. After imposing the collocation nodes to the main BVPs, we reduce the variational problems to the solution of algebraic equations. It should be noted that the robustness of operational matrices of differentiation with respect to the integration ones is shown through illustrative examples. Complete comparisons with other methods and superior results confirm the validity and applicability of the presented method. © 2013 Emran Tohidi and Adem Kiliçman.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
International Journal of Heat and Mass Transfer | Year: 2012

An analysis is carried out to investigate the steady two-dimensional stagnation-point flow of a water based nanofluid over an exponentially stretching/shrinking sheet in its own plane. Using a similarity transformation, the governing mathematical equations are transformed into coupled, nonlinear ordinary differential equations which are then solved numerically for three types of nanoparticles, namely copper (Cu), alumina (Al 2O 3), and titania (TiO 2) in the water based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, the local Nusselt number and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction and the stretching/shrinking parameter λ on the fluid flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. The range of the parameter λ where the similarity solution exists for the steady stagnation-point flow over an exponentially stretching/shrinking sheet is larger compared with the linear stretching/shrinking case. © 2012 Elsevier Ltd. All rights reserved.

Mirsanei H.S.,Mazandaran University of Science and Technology | Zandieh M.,Shahid Beheshti University | Moayed M.J.,University Putra Malaysia | Khabbazi M.R.,University Putra Malaysia
Journal of Intelligent Manufacturing | Year: 2011

One of the scheduling problems with various applications in industries is hybrid flow shop. In hybrid flow shop, a series of n jobs are processed at a series of g workshops with several parallel machines in each workshop. To simplify the model construction in most research on hybrid flow shop scheduling problems, the setup times of operations have been ignored, combined with their corresponding processing times, or considered non sequence-dependent. However, in most real industries such as chemical, textile, metallurgical, printed circuit board, and automobile manufacturing, hybrid flow shop problems have sequence-dependent setup times (SDST). In this research, the problem of SDST hybrid flow shop scheduling with parallel identical machines to minimize the makespan is studied. A novel simulated annealing (NSA) algorithm is developed to produce a reasonable manufacturing schedule within an acceptable computational time. In this study, the proposed NSA uses a well combination of two moving operators for generating new solutions. The obtained results are compared with those computed by Random Key Genetic Algorithm (RKGA) and Immune Algorithm (IA) which are proposed previously. The results show that NSA outperforms both RKGA and IA. © Springer Science+Business Media, LLC 2009.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
International Journal of Heat and Mass Transfer | Year: 2012

The boundary layer of an unsteady two-dimensional stagnation-point flow of a nanofluid is further investigated. The similarity equations are solved numerically for three types of nanoparticles, namely copper (Cu), alumina (Al 2O 3), and titania (TiO 2) in the water based fluid with Prandtl number Pr = 6.2. The skin friction coefficient, the local Nusselt number, and the velocity and temperature profiles are presented and discussed. Effects of the solid volume fraction parameter φ on the fluid flow and heat transfer characteristics are thoroughly examined. Interesting observation is that there are dual solutions seen for negative values of the unsteadiness parameter A (decelerating flow with A < 0). © 2012 Elsevier Ltd. All rights reserved.

Baqiah H.,National University of Malaysia | Ibrahim N.B.,National University of Malaysia | Abdi M.H.,National University of Malaysia | Halim S.A.,University Putra Malaysia
Journal of Alloys and Compounds | Year: 2013

High transparent In2O3 and Cr-doped In 2O3 (In2-xCrxO3) nanocrystalline thin films were prepared using a simple sol-gel method followed by a spin coating technique. The effect of Cr concentration on the structural, microstructure, electrical and optical properties of In2-xCr xO3 were systematically investigated using X-ray diffractometer (XRD), atomic force microscopy (AFM), UV-vis spectroscopy, field emission scanning electron microscopy (FESEM) and Hall effect technique. The films have good crystallization with preferred orientation to (222) direction. The lattice parameters, a, of In2O3 system increased at lowest dopants (x = 0.025) and decreased as the dopant was further increased. The optical transmittance of films increased up to 98% for x = 0.05 and decreased for further Cr concentrations. From AFM measurement the films nanocrystals morphology was depending on Cr concentrations. The band gap was around 3.76 eV for pure and with x 6 0.075 however it increased. The effect of Cr concentrations on conducting mechanisms of In2O3 film has been investigated from 80 to 300 K using thermal activated conduction band and hopping models. The films, at x = 0.0-0.075, have typical semiconductor behaviour. Three different conducting mechanisms have been estimated. All thermal activation energies and conduction hopping parameters have been determined and analysed in details. © 2013 Elsevier B.V. All rights reserved.

Isahak W.N.R.W.,National University of Malaysia | Hisham M.W.M.,National University of Malaysia | Yarmo M.A.,National University of Malaysia | Yun Hin T.-Y.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2012

The paper provides an updated review on thermal conversion of biomass for the production of liquid products referred as bio-oil. This technology is described focusing on the characterization of feedstock, reactor design, products formation and upgrading. For feedstock characterization is covered in terms of several pretreatment methods. The reactor designs are illustrated number of design ranging from fixed bed to circulating fluidized bed. The properties of bio-oil composition have caused increasingly extensive research to be undertaken to address properties that need modification and this area is reviewed in terms of physical, catalytic and chemical upgrading. The mechanism of the products formation is also illustrated by several chemical routes. Reactor parameters such as heating rate, temperature of pyrolysis, catalysts etc are reviewed. © 2012 Elsevier Ltd.

Ishak A.,National University of Malaysia | Yacob N.A.,University Technology of MARA | Bachok N.,University Putra Malaysia
Meccanica | Year: 2011

The steady laminar boundary layer flow over a moving plate in a moving fluid with convective surface boundary condition and in the presence of thermal radiation is investigated in this paper. Under certain conditions, the present problem reduces to the classical Blasius and Sakiadis problems. The effects of radiation and convective parameters on the thermal field are thoroughly examined and discussed. Dual solutions are found to exist when the plate and the fluid move in the opposite directions. © 2010 Springer Science+Business Media B.V.

Kadier A.,National University of Malaysia | Simayi Y.,University Putra Malaysia | Kalil M.S.,National University of Malaysia | Abdeshahian P.,National University of Malaysia | Hamid A.A.,National University of Malaysia
Renewable Energy | Year: 2014

Hydrogen is gaining international attention as a sustainable energy carrier with the potential to replace fossil fuels. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass. A large number of substrates have been used as fuel sources. The major substrates that have been tested include wastewaters, fermentable and non-fermentable organic materials. This article mainly reviews the various substrates that have been used in MECs so far, also their resulting performance, as well as future potential substrates discussed. Besides, in this paper, a short review of recent advances in electrode material and a configuration of both the anode and cathode in MECs are provided. © 2014 Elsevier Ltd.

Shamsuri A.A.,National University of Malaysia | Shamsuri A.A.,University Putra Malaysia | Daik R.,National University of Malaysia
Reviews on Advanced Materials Science | Year: 2015

In this paper, we reviewed the applications of hydrophilic and hydrophobic ionic liquids including their mixtures particularly between ionic liquids and chemical compounds for preparation of advanced polymer blends and composites. In the preceding researches we have found that ionic liquids and their mixtures could be effectively used as environmentally friendly solvent, plasticizer, coupling agent and compatibilizer. These materials have the ability to improve properties of polymer blends and composites that consisted of natural and synthetic polymers. On the other hand, we also included our previous and other studies that consumed the mixture of ionic liquids and chemical compounds for preparation of polymer blends and composites in the form of aerogels, films, composite films and biocomposites. © 2015 Advanced Study Center Co. Ltd.

Dahlan N.D.,University Putra Malaysia | Jones P.J.,University of Cardiff | Alexander D.K.,University of Cardiff
Building and Environment | Year: 2011

This study assessed the influences of operative temperature on occupants' perceptions of indoor thermal condition in three non-air-conditioned multi-storey hostels in Klang Valley, Malaysia. The thermal conditions of 24 measured rooms were recorded with and without an operating ceiling fan from May until July 2007. Measurements were made simultaneously at three different floor levels, namely, at the first, fifth and top floor of each of the case study hostels. A questionnaire survey was completed by 298 female student occupants of the same case study hostels. The results suggested that even though a significance above p < 0.01 was recorded between the operative temperatures with and without fan operation, the temperature difference remained small, i.e., from 0.5 K to 1 K. The findings of the questionnaire survey showed that the occupants perceived the thermal conditions in rooms that were shaded with a projected balcony (shading ratio of 0.9), a long roof overhang (shading ratio of 1.6) and an operable window-to-wall ratio of 0.3 to be thermally comfortable. © 2010 Elsevier Ltd.

Dominick D.,University Putra Malaysia | Juahir H.,University Putra Malaysia | Latif M.T.,National University of Malaysia | Zain S.M.,University of Malaya | Aris A.Z.,University Putra Malaysia
Atmospheric Environment | Year: 2012

This study aims to investigate possible sources of air pollutants and the spatial patterns within the eight selected Malaysian air monitoring stations based on a two-year database (2008-2009). The multivariate analysis was applied on the dataset. It incorporated Hierarchical Agglomerative Cluster Analysis (HACA) to access the spatial patterns, Principal Component Analysis (PCA) to determine the major sources of the air pollution and Multiple Linear Regression (MLR) to assess the percentage contribution of each air pollutant. The HACA results grouped the eight monitoring stations into three different clusters, based on the characteristics of the air pollutants and meteorological parameters. The PCA analysis showed that the major sources of air pollution were emissions from motor vehicles, aircraft, industries and areas of high population density. The MLR analysis demonstrated that the main pollutant contributing to variability in the Air Pollutant Index (API) at all stations was particulate matter with a diameter of less than 10 μm (PM 10). Further MLR analysis showed that the main air pollutant influencing the high concentration of PM 10 was carbon monoxide (CO). This was due to combustion processes, particularly originating from motor vehicles. Meteorological factors such as ambient temperature, wind speed and humidity were also noted to influence the concentration of PM 10. © 2012 Elsevier Ltd.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
PLoS ONE | Year: 2013

The steady boundary layer flow of a viscous and incompressible fluid over a moving vertical flat plate in an external moving fluid with viscous dissipation is theoretically investigated. Using appropriate similarity variables, the governing system of partial differential equations is transformed into a system of ordinary (similarity) differential equations, which is then solved numerically using a Maple software. Results for the skin friction or shear stress coefficient, local Nusselt number, velocity and temperature profiles are presented for different values of the governing parameters. It is found that the set of the similarity equations has unique solutions, dual solutions or no solutions, depending on the values of the mixed convection parameter, the velocity ratio parameter and the Eckert number. The Eckert number significantly affects the surface shear stress as well as the heat transfer rate at the surface. © 2013 Bachok et al.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
Journal of the Franklin Institute | Year: 2013

The steady two-dimensional stagnation point flow toward a stretching/shrinking sheet with the bottom surface of the sheet heated by convection from a hot fluid is considered. The governing partial differential equations are transformed into ordinary differential equations, before being solved numerically. Results for the skin friction coefficient and the local Nusselt number as well as the temperature profiles are presented for different values of the governing parameters. Effects of the governing parameters on the heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. © 2013 The Franklin Institute.

Sarbini S.R.,University Putra Malaysia | Kolida S.,University of Reading | Gibson G.R.,University of Reading | Rastall R.A.,University of Reading
British Journal of Nutrition | Year: 2013

The fermentation selectivity of a commercial source of α-gluco- oligosaccharides (BioEcolians; Solabia) was investigated in vitro. Fermentation by faecal bacteria from four lean and four obese healthy adults was determined in anaerobic, pH-controlled faecal batch cultures. Inulin was used as a positive prebiotic control. Samples were obtained at 0, 10, 24 and 36 h for bacterial enumeration by fluorescent in situ hybridisation and SCFA analyses. Gas production during fermentation was investigated in non-pH-controlled batch cultures. α-Gluco-oligosaccharides significantly increased the Bifidobacterium sp. population compared with the control. Other bacterial groups enumerated were unaffected with the exception of an increase in the Bacteroides-Prevotella group and a decrease in Faecalibacterium prausnitzii on both α-gluco-oligosaccharides and inulin compared with baseline. An increase in acetate and propionate was seen on both substrates. The fermentation of α-gluco-oligosaccharides produced less total gas at a more gradual rate of production than inulin. Generally, substrates fermented with the obese microbiota produced similar results to the lean fermentation regarding bacteriology and metabolic activity. No significant difference at baseline (0 h) was detected between the lean and obese individuals in any of the faecal bacterial groups studied. Copyright © 2012 The Authors.

Jamaludin N.,University Putra Malaysia | Monsi M.,University Putra Malaysia | Hassan N.,National University of Malaysia | Suleiman M.,University Putra Malaysia
AIP Conference Proceedings | Year: 2013

The purpose of this paper is to establish a new modified method. This modified procedure is called the Interval Symmetric Single Step-5 Delta Procedure ISS-5δ. This research start with some disjoints intervals as the initial intervals which contain the polynomial zeros. The procedure of ISS-5δ will generate smaller bounded close intervals. The procedure is run on 5 test polynomials and the results obtained show that this procedure is more efficient than previous procedure. © 2013 AIP Publishing LLC.

Sarmani A.R.,University Putra Malaysia | Abu Bakar M.H.,University Putra Malaysia | Bakar A.A.A.,National University of Malaysia | Mahamd Adikan F.R.,University of Malaya | Mahdi M.A.,University Putra Malaysia
Optics Express | Year: 2011

We report an ultra-long Raman laser that implemented a variable pumping scheme in backward and forward configurations. Rayleigh backscattering effects were realized in the 51 km fiber length that functioned as a virtual mirror at one fiber end. With the employment of a fiber Bragg grating that has a peak reflection wavelength at 1553.3 nm, spectral broadening effects were observed. These occurred as the pump power level was diverted more to the forward direction. Owing to this fact, a maximum width of 0.9 nm was measured at 100% forward pumping. The obtained results show that the efficient exploitation of four-wave mixing interactions as well as strong Rayleigh backscattering are beneficial to influence the lasing performances. Both of these nonlinear responses can be adjusted by varying pumping distributions along the fiber longitudinal dimension. © 2011 Optical Society of America.

Chew B.H.,University Putra Malaysia | Shariff Ghazali S.,University Putra Malaysia | Ismail M.,Klinik Kesihatan Seremban 2 | Haniff J.,Hospital Kuala Lumpur | Bujang M.A.,Hospital Kuala Lumpur
Experimental Gerontology | Year: 2013

Providing effective medical care for older patients with type 2 diabetes mellitus (T2D) that may contribute to their active aging has always been challenging. We examined the independent effect of age ≥ 60. years on disease control and its relationship with diabetes-related complications in patients with T2D in Malaysia. This was a cross-sectional study using secondary data from the electronic diabetes registry database Adult Diabetes Control and Management (ADCM). A total of 303 centers participated and contributed a total of 70,889 patients from May 2008 to the end of 2009. Demographic data, details on diabetes, hypertension, dyslipidemia and their treatment modalities, various risk factors and complications were updated annually. Independent associated risk factors were identified using multivariate regression analyses. Fifty-nine percent were female. Malay comprised 61.9%, Chinese 19% and Indian 18%. There were more Chinese, men, longer duration of diabetes and subjects that were leaner or had lower BMI in the older age group. Patients aged ≥ 60. years achieved glycemic and lipid targets but not the desired blood pressure. After adjusting for duration of diabetes, gender, ethnicity, body mass index, disease control and treatment, a significantly higher proportion of patients ≥ 60. years suffered from reported diabetes-related complications. Age ≥ 60. years was an independent risk factor for diabetes-related complications despite good control of cardiovascular risk factors. Our findings caution against the currently recommended control of targets in older T2D patients with more longstanding diseases and complications. © 2013 Elsevier Inc.

Yusof R.,University of Technology Malaysia | Abdul Rahman R.Z.,University Putra Malaysia | Khalid M.,University of Technology Malaysia | Ibrahim M.F.,National University of Malaysia
Journal of the Franklin Institute | Year: 2011

A technique for the modeling of nonlinear control processes using fuzzy modeling approach based on the TakagiSugeno fuzzy model with a combination of genetic algorithm and recursive least square is proposed. This paper discusses the identification of the parameters at the antecedent and consequent parts of the fuzzy model. For the antecedent fuzzy parameters, genetic algorithm is used to tune them while at the consequent part, recursive least squares approach is used to identify the system parameters. This approach is applied to a process control rig with three subsystems: a heating element, a heat exchanger and a compartment tank. Experimental results show that the proposed approach provides better modeling when compared with Takagi Sugeno fuzzy modeling technique and the linear modeling approach. © 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Chaharborj S.S.,University Putra Malaysia | Kiai S.M.S.,Nuclear Science and Technology Research Institute, Iran
Journal of Mass Spectrometry | Year: 2010

This article reports on some theoretical studies concerning the impulsional mode of a cylindrical ion trap (CIT) supplied with a periodic impulsional radio frequency (rf) voltage of the form Vaccosωt/(1 - kcos2ωt) with 0 ≤ k < 1. The performance characteristics of CIT impulsional mode, for the twelve stability regions, were computed using fifth order Runge-Kutta method and were compared to the classical sinusoidal mode k = 0. Also, the results show that, for the same equivalent operating point in two stability diagrams (having the same βz) the associated modulated secular ion frequencies behavior are the same. Copyright © 2010 JohnWiley & Sons, Ltd.

Shahidan M.F.,University Putra Malaysia | Shahidan M.F.,University of Cardiff | Jones P.J.,University of Cardiff | Gwilliam J.,University of Cardiff | Salleh E.,National University of Malaysia
Building and Environment | Year: 2012

This study focuses on the optimum cooling effect of trees with ground materials modification in mitigating the urban heat island (UHI) and the benefits towards building energy performance in tropical climate. The modification focused on both physical properties - i.e. tree canopy density and quantity; and the albedo values of ground materials. Two phases of methodology were developed and applied using field measurement and computer simulation. This study measured the average monthly UHI intensity found to be +2.6 °C. In mitigating its impact, higher levels of tree canopy density (LAI 9.7) coupled with "cool" materials (albedo of 0.8) produced the largest urban air temperature reduction. Simulations predicted an average air temperature reduction of 2.7 °C when compared with the current condition. Further, both modifications were found to produce a potential building cooling load reduction of up to 29%. In fact, the optimum improvement of both outdoor and indoor environment was influenced by three major physical factors, namely, larger tree quantity, higher canopy density and cool materials. Thus, it is suggested that appropriate guidelines, influencing implementation of these improvements could be implemented in order to mitigate the UHI effect in tropical climate. © 2012 Elsevier Ltd.

Abdullah M.,Yemen University of Science and Technology | Othman M.,University Putra Malaysia | Othman M.,Computational Science and Mathematical Physics Laboratory
Procedia Computer Science | Year: 2013

The advent of cloud computing as a new model of service provisioning in distributed systems, encourages researchers to investigate its benefits and drawbacks in executing scientific applications such as workflows. In this research, we attempt to investigate the use of a Divisible Load Theory (DLT) to design efficient strategies to minimize the overall processing time for scheduling jobs in compute cloud environments. We consider homogeneous processors in our analysis and we derive a closed-form solution for the load fractions to be assigned to each processors. Our analysis also attempts to schedule the jobs such a way that cloud provider can gain maximum benefit for his service and Quality of Service (QoS) requirement user's job. Finally, we quantify the performance of the strategies via rigorous simulation studies. © 2013 The Authors. Published by Elsevier B.V.

Sadafi N.,University Putra Malaysia | Salleh E.,University Putra Malaysia | Haw L.C.,National University of Malaysia | Jaafar Z.,University Putra Malaysia
Energy and Buildings | Year: 2011

Thermal comfort conditions in residential buildings vary according to the designs, modifications of the house and adaptations of the occupants. The purpose of this paper is to examine thermal performance of terrace housing in tropical climate by exploiting internal courtyard. A case study of a terrace house was chosen, where field measurement was conducted during a three-day recording in naturally ventilated spaces of the house. Results from field measurement were used to develop a baseline model for computational experiment. Subsequently, the effects of introducing an internal courtyard on thermal comfort performance of the building were investigated using ECOTECT software. The results from simulation analysis indicate that, applying internal courtyard in the terrace house will improve natural ventilation and thermal comfort in spaces with openings to the outside environment. It shows that the influence of the internal courtyard on the thermal condition has a strong reliance on the envelop openings. This study suggests that the internal courtyard of a terrace house can affect improvements in thermal conditions of the courtyard's surrounding spaces, provided sufficient and efficient openings with shading devices are suitably incorporated. © 2010 Elsevier B.V. All rights reserved.

Mohammad M.,University of Selangor | Abdullah S.,National University of Malaysia | Jamaludin N.,National University of Malaysia | Innayatullah O.,University Putra Malaysia
Materials and Design | Year: 2014

This paper presents the capability of acoustic emission (AE) technique to predict the fatigue life of SAE 1045 carbon steel using a newly formulated statistical distribution. The specific AE parameters and the number of cycles to failure of the tested specimens were correlated using the Weibull distribution approach. The AE and strain signals were experimentally measured using the AE sensor and strain gauge respectively, with the sensors attached to the specimen during the cyclic test at several stress levels of constant amplitude loadings. The empirical model developed from the newly developed h- N curve, in correlation to the AE hits-number and cycles to failure, suggested that the AE technique has the potential to assess fatigue life for SAE 1045 carbon steel. Also, the validation results presented in the Weibull probability distribution technique are presented in the end of this paper. © 2013 Elsevier Ltd.

Shamsuri A.A.,National University of Malaysia | Shamsuri A.A.,University Putra Malaysia | Daik R.,National University of Malaysia
Materials | Year: 2013

An ionic liquid, 1-n-butyl-3-methylimidazolium chloride (BmimCl) was blended with urea at 1:1 mole ratio to create a BmimCl/Urea mixture. The agarose/talc composite films containing the BmimCl/Urea mixture were then acquired through a gelation method. The weight ratio of agarose and talc was fixed at 4:1, while the content of BmimCl/Urea was varied from 0 to 10 wt % relative to the overall weight of the composite films. The tensile stress and modulus results showed the optimum BmimCl/Urea content in the composite film lies at 8 wt %. The talc particles are embedded in the agarose matrix and there are no pullouts for the composite films containing BmimCl/Urea as demonstrated by SEM micrographs. The addition of BmimCl/Urea increased the glass transition temperature of the composite films, however, the thermal decomposition temperature decreased drastically. FTIR and FT-Raman spectra indicated the existence of interaction between agarose and talc, which improves their interfacial adhesion. As a conclusion, a BmimCl/Urea mixture can be utilized as a coupling agent for agarose/talc composite films. © 2013 by the authors.

Masdi H.,University Putra Malaysia | Mariun N.,National University of Malaysia
International Review of Electrical Engineering | Year: 2010

The study reported in this paper was aimed to investigate transient response of power transformer when lightning current pass through its winding. Analysis of distribution voltage at the winding taps was done, both by experimental and numerical simulation, by applying IEC-71 standard current surge (8/20 μs impulse current and 1.2/50 μs impulse voltage). Transformer's constants as: R, L, C were derived from the transformer construction, which consists of 9 winding layers at HV-side. The wave-shapes of the voltage across the winding sections were recorded. The response of the windings was then compared with results of a simulation using EMTDC/PSCAD. The simulation based on an RLC network model resulted in wave-shapes that are in good agreement to those of the experiment. Both results of the simulation and experiment show that the distribution of the impulse voltage across the windings is non linear, especially during the period of fraction of microseconds. Furthermore, results of the investigation show that a simple capacitance network model is sufficient for study of the impulse voltage distribution across transformer windings. © 2010 Praise Worthy Prize S.r.l.

Bachok N.,University Putra Malaysia | Ishak A.,National University of Malaysia | Pop I.,Babes - Bolyai University
Journal of Heat Transfer | Year: 2013

An analysis is carried out to study the steady two-dimensional stagnation-point flow of a nanofluid over a stretching/shrinking sheet in its own plane. The stretching/shrinking velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. A similarity solution is presented which depends on the Prandtl number Pr, Lewis number Le, Brownian motion parameter Nb and thermophoresis parameter Nt. It is found that the local Nusselt number is a decreasing function, while the local Sherwood number is an increasing function of each parameters Pr, Le, Nb, and Nt. Different from a stretching sheet, the solutions for a shrinking sheet are nonunique. Copyright © 2013 by ASME.

Yusoff N.I.M.,National University of Malaysia | Jakarni F.M.,University Putra Malaysia | Nguyen V.H.,University of Transport and Communications | Hainin M.R.,University of Technology Malaysia | Airey G.D.,University of Nottingham
Construction and Building Materials | Year: 2013

This study investigates the advantages and drawbacks of several mathematical models that fit or describe linear viscoelastic rheological data of unaged and aged unmodified bitumens and polymer-modified bitumens. The complex modulus data is collected by means of a dynamic shear rheometer (DSR) within the LVE response. The result indicates that the models can be used to satisfactorily fit the rheological properties of unmodified bitumens. In general, the Generalised Modified Sigmoidal Model is the most outstanding model, followed by the Sigmoidal Model, Christensen, Anderson and Marasteanu (CAM) Model and Christensen Model and Anderson (CA) Model. However, all models suffer from similar drawbacks in that they are unable to describe the rheological properties of unaged polymer-modified bitumens precisely due to the presence of semi-crystalline and elastomeric structures in the binders and render a breakdown in the time temperature superposition principle (TTSP). © 2012 Elsevier Ltd. All rights reserved.

Sambasivan M.,University of Malaysia, Kelantan | Siew-Phaik L.,Campus Management | Abidin Mohamed Z.,Universiti Sains Islam Malaysia | Leong Y.C.,University Putra Malaysia
International Journal of Production Economics | Year: 2013

Integration of various theories is essential to completely understand and explain strategic alliances in a supply chain. The purpose of this paper is to develop a framework by integrating the features of transaction cost theory, resource-based theory, contingency theory, social exchange theory, and Kelley's personal relationship theory and test the framework through empirical research. The present study addresses the impact of strategic alliance motives, environment, asset specificity, perception of opportunistic behavior, interdependence between supply chain partners, and relational capital on strategic alliance outcomes. Besides, the study has also tested the role of relational capital as a central mediating construct. A sample of 2156 companies representing different industries in manufacturing in Malaysia was selected for the distribution of questionnaire. We tested the structural model using structural equation modeling (SEM). Based on the results, we conclude the following significant relationships: (1) strategic alliance motives and perception of opportunistic behavior on interdependence and relational capital, (2) interdependence on relational capital, (3) environment on strategic alliance motives, (4) relational capital on strategic alliance outcomes, and (4) the mediating role of relational capital. The current study adds significantly to the body of knowledge on strategic alliances and can help managers identify factors that influence the success of strategic alliances and provide a proper direction to develop robust and effective collaborative relationships between supply chain partners. © 2012 Elsevier B.V. All rights reserved.

Baharom S.,University Putra Malaysia | Shukur Z.,National University of Malaysia
Information and Software Technology | Year: 2011

Context: Testing a module that has memory using the black-box approach has been found to be expensive and relatively ineffective. Instead, testing without knowledge of the specifications (white-box approach) may not be effective in showing whether a program has been properly implemented as stated in its specifications. We propose instead a grey-box approach called Module Documentation-based Testing or MD-Test, the heart of which is an automatic generation of the test oracle from the external and internal views of the module. Objective: This paper presents an empirical analysis and comparison of MD-Test against three existing testing tools. Method: The experiment was conducted using a mutation-testing approach, in two phases that assess the capability of MD-Test in general and its capability of evaluating test results in particular. Results: The results of the general assessment indicate that MD-Test is more effective than the other three tools under comparison, where it is able to detect all faults. The second phase of the experiment, which is significant to this study, compares the capabilities of MD-Test and JUnit-black using the test evaluation results. Likewise, an analysis of the test evaluation results shows that MD-Test is more effective and efficient, where MD-Test is able to detect at least the same number of faults as, or is at par with, the black-box approach. Conclusion: It is concluded that test evaluation using grey-box approach is more effective and efficient that the black-box approach when testing a module that has memory. © 2011 Elsevier B.V. All rights reserved.

Jahanbani H.,University Putra Malaysia | El-Shafie A.H.,National University of Malaysia
Paddy and Water Environment | Year: 2011

There are various methods for computing reference evapotranspiration (ETo) using meteorological data. However, such models tend to perform well for predicting ETo close to the mean, but do not keep accurate performance with extreme observations. It is recognized that the Penman-Monteith (PM) model has the best performance when rich data is available to calculate the ETo, which is not frequently available to a certain extent. In case of poor data, such as prediction of futuristic ETo while investigating climate change effect, although there are models other than PM like Hargreaves-Samani (HGS), the universal sustainability of these models are not quit proved. Accordingly, the calculation of ETo still required numerous research to reach accurate estimation of ETo specially when there is lacking for data to utilize PM method. Recently, methods based on artificial intelligence (AI) have been suggested to provide reliable prediction model for several application in engineering. This manuscript employed artificial neural network (ANN) for predicting daily ETo at Rasht city located northern part of Iran using minimum and maximum daily temperatures collected from 1975 to 1988 of the region. A comprehensive data analysis utilizing the daily time series, minimum and maximum temperatures and solar radiation (Tmin, Tmax and Rs), as input pattern to predict daily ETo at the current month and for the following month is proposed. The employed ANN model was feed forward backpropagation (FFBP) type with Bayesian regulation backpropagation. The mean square error, mean absolute error, mean absolute relative error and regression coefficient are the statistical performance indices used to evaluate the model accuracy. The results showed that the proposed ANN model could successfully be used to predict daily ETo using only maximum and minimum temperatures with significant level of accuracy. In addition, results show that the proposed ANN model outperforms HGS method. © 2010 Springer-Verlag.

Ali M.H.,National University of Malaysia | Suleiman N.,University Putra Malaysia
International Journal of Production Economics | Year: 2016

The aim of this paper is to explore and evaluate the relationships and links between standard food production practices and the principles of sustainable production. As part of the study, several explanatory frameworks are explored and discussed. Interviews with industry experts and a survey covering more than 600 Malaysian SMEs producing halal foods were commissioned. The results provide in-depth insights into sustainable food production practices. The findings of this study are intended to be used: (a) to assist an understanding of the synergies between standard production practices and sustainable production principles; (b) to clarify whether halal food production is capturing aspects of sustainable development; and (c) to identify opportunities for small and medium sized enterprises to venture into sustainable initiatives at minimal cost. Additionally, the investigation provides evidence that compliance with environmental standards can go hand in hand with the meeting of other sets of production standards. © 2016 Elsevier B.V.

Shamsuri A.A.,National University of Malaysia | Shamsuri A.A.,University Putra Malaysia | Daik R.,National University of Malaysia
BioResources | Year: 2012

Agarose films were formed with the addition of 30 to 70 wt% choline chloride/urea eutectic-based ionic liquid (ChCl/Urea). The ChCl/Urea was prepared through complexation at a 1:2 mole ratio. The films were prepared by dissolving ChCl/Urea in distilled water followed by dispersion of the agarose at 95 °C. The solution was gelled at room temperature, and the formed gel was dried in an oven overnight at 70 °C. Mechanical testing indicated that the agarose film containing 60 wt% ChCl/Urea had higher tensile extension and tensile strain at break compared to the pristine agarose film. The addition of ChCl/Urea also reduced the glass transition temperature (Tg) of agarose films. Cross-section SEM images of the agarose films showed that surface roughness disappeared with the incorporation of ChCl/Urea. FTIR spectra confirmed the presence of intermolecular hydrogen bonding between agarose and ChCl/Urea. XRD patterns demonstrated that an amorphous phase was obtained when ChCl/Urea was added. Agarose films containing more ChCl/Urea exhibited higher transparency, as measured by a UV-Vis spectrometer. In summary, the physicochemical properties of agarose films were evidently affected by the incorporation of the ChCl/Urea as a plasticizing agent.

Fathinul F.,University Putra Malaysia | Nordin A.J.,University Putra Malaysia | Lau W.F.E.,University of Melbourne | Lau W.F.E.,Center for Molecular Imaging
Cell Biochemistry and Biophysics | Year: 2013

Molecular imaging employing 18[F]FDG-PET/CT enables in-vivo visualization, characterisation and measurement of biological process in tumour at the molecular and cellular level. In oncology, this approach can be directly applied as translational biomarkers of disease progression. In this article, the improved roles of FDG as an in-vivo glycolytic marker which reflect biological changes across in-vitro cellular environment are discussed. New understanding in how altered metabolism via glycolytic downstream drivers of malignant transformation as reviewed below offers unique promise as to monitor tumour aggressiveness and hence optimize the therapeutic management. © 2012 Springer Science+Business Media, LLC.

Nouri H.,Islamic Azad University at Sanandaj Branch | Hong T.S.,University Putra Malaysia
Journal of Manufacturing Systems | Year: 2013

The cellular manufacturing system (CMS) is considered as an efficient production strategy for batch type production. The CMS relies on the principle of grouping machines into machine cells and grouping machine parts into part families on the basis of pertinent similarity measures. The bacteria foraging optimization (BFO) algorithm is a modern evolutionary computation technique derived from the social foraging behavior of Escherichia coli bacteria. Ever since Kevin M. Passino invented the BFO, one of the main challenges has been the employment of the algorithm to problem areas other than those of which the algorithm was proposed. This paper investigates the first applications of this emerging novel optimization algorithm to the cell formation (CF) problem. In addition, for this purpose matrix-based bacteria foraging optimization algorithm traced constraints handling (MBATCH) is developed. In this paper, an attempt is made to solve the cell formation problem while considering cell load variations and a number of exceptional elements. The BFO algorithm is used to create machine cells and part families. The performance of the proposed algorithm is compared with a number of algorithms that are most commonly used and reported in the corresponding scientific literature such as K-means clustering, the C-link clustering and genetic algorithm using a well-known performance measure that combined cell load variations and a number of exceptional elements. The results lie in favor of better performance of the proposed algorithm. © 2012 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

Sambasivan M.,University of Malaysia, Kelantan | Bah S.M.,University Putra Malaysia | Ho J.-A.,University Putra Malaysia
Journal of Cleaner Production | Year: 2013

In spite of the significant amount of work that has been conducted to investigate the impact of environmental proactivity on firm financial performance, limited research has focused on other firm performance outcomes such as operational performance and stakeholder satisfaction. The roles played by interacting and mediating constructs have not been addressed adequately in the environmental proactivity/firm performance literature. Drawing on stakeholder theory and the resource-based view of the firm, this study on 291 firms in Malaysia has hypothesized that environmental proactivity is positively related to (1) operational performance, (2) organizational learning, (3) environmental performance, (4) stakeholder satisfaction and (5) financial performance. The study has also hypothesized that the types of technologies deployed to address environmental issues moderates the relationship between environmental proactivity and operational performance, whilst environmental performance mediates the relationship between environmental proactivity and stakeholder satisfaction, which in turn mediates the relationship between environmental proactivity and financial performance. Using structural equation modeling (SEM) for the data analysis, findings indicate that environmental proactivity is positively related to operational performance, organizational learning, environmental performance, stakeholder satisfaction and financial performance. Significantly, the mediating role of stakeholder satisfaction is also supported by the data even though the mediating role of environmental performance and the moderating role of types of technologies are not supported by findings. © 2012 Elsevier Ltd. All rights reserved.

Boretti A.,University of Ballarat | Boretti A.,Missouri University of Science and Technology | Osman A.,PROTON Holdings Berhad | Aris I.,University Putra Malaysia
International Journal of Hydrogen Energy | Year: 2011

This short communication proposes novel two stroke engine burning hydrogen in oxygen in presence of large amounts of steam as residual gases. This engine has a bowl-in-piston combustion chamber, exhaust valves only and it uses direct injection of hydrogen, oxygen and water. Diesel-like compression ignition combustion is achieved by injecting the oxygen and the hydrogen in the surrounding steam close to a continuously operated glow plug. The operation of the engine is simulated by commercial softwares. The water injection enables acceptable metal temperatures and reduced heat losses. First computational results show brake efficiencies above 55% achieved with mass of water injected about twice the mass of oxygen and hydrogen mixture and operation with a significant amount of exhaust gas recirculation. It seems reasonable to guess efficiencies of the fully optimised and developed engine approaching the 60% mark, 20% higher than those of the state-of-the-art H2ICEs designed for operation with air using the spark-ignition engine concept as well as of those projected for Diesel engines operating with exhaust energy recovery. Worth of mention is also the much higher power density following the two stroke operation. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Anezaki K.,Japan Institute for Environmental Sciences | Kannan N.,University Putra Malaysia | Nakano T.,Osaka University
Environmental science and pollution research international | Year: 2015

This study reports the concentrations and congener partners of polychlorinated biphenyls (PCBs) in commercially available paints. Polycyclic-type pigments containing dioxazine violet (pigment violet (PV) 23, PV37) and diketopyrrolopyrrole (PR254, PR255) were found to contain PCB-56, PCB-77, PCB-40, PCB-5, and PCB-12, and PCB-6, PCB-13, and PCB-15, respectively, as major congeners. Dioxazine violet is contaminated with by-products during synthesis from o-dichlorobenzene, which is used as a solvent during synthesis, and diketopyrrolopyrrole is contaminated with by-products during synthesis from p-chlorobenzonitrile. The concentration of PCBs in paint containing PV23 or PV37 was 0.050-29 mg/kg, and toxic equivalency (TEQ) values ranged 1.1-160 pg-TEQ/g. The concentration of PCBs in paint containing PR254 or PR255 was 0.0019-2.4 mg/kg. Naphthol AS is an azo-type pigment, and PCB-52 was detected in paint containing pigment red (PR) 9 with 2,5-dichloroaniline as its source. PCB-146, PCB-149, and PCB-153 were identified from paint containing PR112 produced from 2,4,5-trichloroaniline, as major congeners. These congeners have chlorine positions similar to aniline, indicating that these congeners are by-products obtained during the synthesis of pigments. The concentrations of PCBs in paints containing PR9 and PR112 were 0.0042-0.43 and 0.0044-3.8 mg/kg, respectively. The corresponding TEQ for PR112 was 0.0039-8.6 pg-TEQ/g.

Hoong Y.B.,Fibre and Biocomposite Center | Paridah M.T.,University Putra Malaysia
Materials and Design | Year: 2013

The main objective in this study were to investigate the physical properties, mechanical properties and bonding qualities of oil palm stem (OPS) plywood pre-preg using low molecular weight phenol-formaldehyde (LmwPF). The properties evaluated were physical properties (resin uptake, weight percent gain), mechanical properties (bending strength) and bonding qualities (dry test, WPB test). The results showed that, the physical properties of OPS plywood were significant at resin concentration and veneer moisture content. Moreover, the mechanical properties and bonding performance of the pre-preg OPS plywood were influenced by the pressing time. The high grade OPS plywood with improved at least 227% MOR and 348% MOE compared to commercial OPS plywood, with greater in MOR (31%) and MOE (12%) higher compared than the commercial tropical mix light hardwood (MLHW) plywood. All the shear strength of pre-preg OPS plywood panel were achieved with their minimum requirements and satisfied all the specific testing based on the standard European Norms EN 314-1 and EN 314-2 for the interior and exterior application purposes. The output of this pilot scale study proved that high performance OPS plywood could produced through pre-preg enhancement method in the current plywood mills in which provides broader area of applications compared with conventional OPS plywood. For instant, the pre-preg OPS plywood which is suitable for structural application, concrete formwork, heavy duty interior structuring board, load bearing plywood, marine grade plywood, was obtained, thus consequently increases the price of OPS plywood panels. © 2012 Elsevier Ltd.

Elbeleze A.A.,Universiti Sains Islam Malaysia | Kilicman A.,University Putra Malaysia | Taib B.M.,Universiti Sains Islam Malaysia
Mathematical Problems in Engineering | Year: 2013

The homotopy perturbation method, Sumudu transform, and He's polynomials are combined to obtain the solution of fractional Black-Scholes equation. The fractional derivative is considered in Caputo sense. Further, the same equation is solved by homotopy Laplace transform perturbation method. The results obtained by the two methods are in agreement. The approximate analytical solution of Black-Scholes is calculated in the form of a convergence power series with easily computable components. Some illustrative examples are presented to explain the efficiency and simplicity of the proposed method. © 2013 Asma Ali Elbeleze et al.

Nouri H.,Islamic Azad University at Sanandaj Branch | Hong T.S.,University Putra Malaysia
Journal of Manufacturing Systems | Year: 2012

The cellular manufacturing system (CMS) is considered as an efficient production strategy for batch type production. The CMS relies on the principle of grouping machines into machine cells and grouping machine parts into part families based on pertinent similarity measures. The bacteria foraging algorithm (BFA) is a new in development computation technique extracted from the social foraging behavior of Escherichia coli (E. coli) bacteria. Ever since Kevin M. Passino invented the BFA, one of the main challenges has been employment of the algorithm to problem areas other than those for which the algorithm was proposed. This research work inquires the first applications of this emerging novel optimization algorithm to the cell formation (CF) problem. In addition, a newly developed BFA-based optimization algorithm for CF is discussed. In this paper, an attempt is made to solve the cell formation problem meanwhile taking into consideration number of voids in cells and a number of exceptional elements based on operational time of the parts required for processing in the machines. The BFA is suggested to create machine cells and part families. The performance of the proposed algorithm is compared with a number of algorithms that are most commonly used and reported in the corresponding scientific literature such as similarity coefficients methods (SCM), rank order clustering (ROC), ZODIAC, GRAFICS, MST, GATSP, GP, K-harmonic clustering (KHM), K-means clustering, C-link clustering, modified ART1, GA (genetic algorithm), evolutionary algorithm (EA), and simulated annealing (SA) using defined performance measures known as modified grouping efficiency and grouping efficacy. The results lie in favor of better performance of the proposed algorithm. © 2012 The Society of Manufacturing Engineers.

Esmaeilzadeh P.,Florida International University | Sambasivan M.,Taylors University | Kumar N.,University of Malaysia, Kelantan | Nezakati H.,University Putra Malaysia
International Journal of Medical Informatics | Year: 2015

Objective: The basic objective of this research is to study the antecedents and outcomes of professional autonomy which is a central construct that affects physicians' intention to adopt clinical decision support systems (CDSS). The antecedents are physicians' attitude toward knowledge sharing and interactivity perception (about CDSS) and the outcomes are performance expectancy and intention to adopt CDSS. Besides, we include (1) the antecedents of attitude toward knowledge sharing-subjective norms, social factors and OCB (helping behavior) and (2) roles of physicians' involvement in decision making, computer self-efficacy and effort expectancy in our framework. Methods: Data from a stratified sample of 335 Malaysian physicians working in 12 public and private hospitals in Malaysia were collected to test the hypotheses using Structural Equation Modeling (SEM). Results: The important findings of our research are: (1) factors such as perceived threat to professional autonomy, performance expectancy, and physicians' involvement in making decision about CDSS have significant impact on physicians' intention to adopt CDSS; (2) physicians' attitude toward knowledge sharing, interactivity perception and computer self-efficacy of physicians play a crucial role in influencing their perceived threat to professional autonomy; and (3) social network, shared goals and OCB (helping behavior) impact physicians' attitude toward knowledge sharing. Conclusions: The findings provide a comprehensive understanding of the factors that influence physicians' intention to adopt CDSS in a developing country. The results can help hospital managers manage CDSS implementation in an effective manner. © 2015 Elsevier Ireland Ltd.

Jahan A.,Islamic Azad University at Semnan | Ismail M.Y.,University Putra Malaysia | Sapuan S.M.,University Putra Malaysia | Mustapha F.,University Putra Malaysia
Materials and Design | Year: 2010

The selection of a material for a specific engineering purpose is a lengthy and expensive process. Approximately always more than one material is suitable for an engineering application, and the final selection is a compromise that brings some advantages as well as disadvantages. One of the issues that emerges from this review is that regardless of the relation of design stages and process selection with material selection, screening and ranking are two vital steps in the material selection. A variety of quantitative selection procedures have been developed to solve this issue, so that a systematic evaluation can be made. This paper seeks to address the following questions: (1) what is the contribution of the literature in the field of screening and choosing the materials? (2) What are the methodologies/systems/tools for material selection of engineering components? (3) Which approaches were prevalently applied? (4) Is there any inadequacy of the approaches? This research not only provides evidence that the multi-criteria decision making approaches has the potential to greatly improve the material selection methodology, but also aids the researchers and decision makers in applying the approaches effectively. © 2009 Elsevier Ltd. All rights reserved.

Hira T.K.,Iowa State University | Sabri M.F.,University Putra Malaysia | Loibl C.,Ohio State University
International Journal of Consumer Studies | Year: 2013

This study investigates the role of financial socialization for investment orientation and household net worth. Combining consumer socialization literature with findings in the behavioural finance literature, survey data were analysed to (1) investigate the relationship among household net worth, financial socialization, indicators of investment orientation and socio-demographic investor characteristics; (2) examine the influence of socio-demographic investor characteristics and financial socialization on indicators of investment orientation; and (3) test whether financial socialization affects household wealth above and beyond socio-demographic and investment orientation factors. Parents emerged as a relevant socialization agent of investors, influencing investment regularity and household net worth above and beyond other factors. This result extends earlier findings about parents' role for a person's financial management and savings behaviour to the investment context. Based on our findings, educators may want to involve parents in their efforts. They may want to emphasize the importance of starting investing regularly at an early age and of continuing to increase involvement in investing over the years. Financial planners and financial counsellors may consider emphasizing these two practices for their clients and involve children of their clients when and where appropriate. © 2012 Blackwell Publishing Ltd.

Mansor M.R.,University Putra Malaysia | Mansor M.R.,Hang Tuah University | Sapuan S.M.,University Putra Malaysia | Zainudin E.S.,University Putra Malaysia | And 2 more authors.
Materials and Design | Year: 2013

We completed natural fiber material selection using AHP method.New product design specifications for parking brake lever was developed.Kenaf bast fiber is the best natural fiber for hybrid polymer composites.Overall AHP consistency ratio obtained is less than 0.10.Validation of the results was made using sensitivity analysis. Due to recent trend and increasing awareness towards sustainable product design, natural based fiber materials are gaining a revival popularity to replace synthetic based fiber in the formulation of composites especially for automotive structural and semi structural applications. In this paper, the Analytical Hierarchy Process (AHP) method was utilized in the selection of the most suitable natural fiber to be hybridized with glass fiber reinforced polymer composites for the design of a passenger vehicle center lever parking brake component. Thirteen (13) candidate natural based fiber materials for the hybridization process were selected and analyzed to determine their overall scores in three (3) main performance indices according to the component product design specifications. Using the AHP method, the kenaf bast fiber yields the highest scores and was selected as the best candidate material to formulate the hybrid polymer composites for the automotive component construction. Sensitivity analysis was also performed and results show that kenaf bast fiber emerged as the best candidate material in two out of three simulated scenarios, which further validates the results gained through the AHP method. © 2013 Elsevier Ltd.

Akgun A.,Middle East Technical University | Sezer E.A.,Hacettepe University | Nefeslioglu H.A.,General Directorate of Mineral Research and Exploration | Gokceoglu C.,Hacettepe University | Pradhan B.,University Putra Malaysia
Computers and Geosciences | Year: 2012

In this study, landslide susceptibility mapping using a completely expert opinion-based approach was applied for the Sinop (northern Turkey) region and its close vicinity. For this purpose, an easy-to-use program, "MamLand," was developed for the construction of a Mamdani fuzzy inference system and employed in MATLAB. Using this newly developed program, it is possible to construct a landslide susceptibility map based on expert opinion. In this study, seven conditioning parameters characterising topographical, geological, and environmental conditions were included in the FIS. A landslide inventory dataset including 351 landslide locations was obtained for the study area. After completing the data production stage of the study, the data were processed using a soft computing approach, i.e., a Mamdani-type fuzzy inference system. In this system, only landslide conditioning data were assessed, and landslide inventory data were not included in the assessment approach. Thus, a file depicting the landslide susceptibility degrees for the study area was produced using the Mamdani FIS. These degrees were then exported into a GIS environment, and a landslide susceptibility map was produced and assessed in point of statistical interpretation. For this purpose, the obtained landslide susceptibility map and the landslide inventory data were compared, and an area under curve (AUC) obtained from receiver operating characteristics (ROC) assessment was carried out. From this assessment, the AUC value was found to be 0.855, indicating that this landslide susceptibility map, which was produced in a data-independent manner, was successful. © 2011 Elsevier Ltd.

Pourghasemi H.R.,Tarbiat Modares University | Jirandeh A.G.,Spatial Academy Team | Pradhan B.,University Putra Malaysia | Xu C.,China Earthquake Administration | Gokceoglu C.,Hacettepe University
Journal of Earth System Science | Year: 2013

The main goal of this study is to produce landslide susceptibility map using GIS-based support vector machine (SVM) at Kalaleh Township area of the Golestan province, Iran. In this paper, six different types of kernel classifiers such as linear, polynomial degree of 2, polynomial degree of 3, polynomial degree of 4, radial basis function (RBF) and sigmoid were used for landslide susceptibility mapping. At the first stage of the study, landslide locations were identified by aerial photographs and field surveys, and a total of 82 landslide locations were extracted from various sources. Of this, 75% of the landslides (61 landslide locations) are used as training dataset and the rest was used as (21 landslide locations) the validation dataset. Fourteen input data layers were employed as landslide conditioning factors in the landslide susceptibility modelling. These factors are slope degree, slope aspect, altitude, plan curvature, profile curvature, tangential curvature, surface area ratio (SAR), lithology, land use, distance from faults, distance from rivers, distance from roads, topographic wetness index (TWI) and stream power index (SPI). Using these conditioning factors, landslide susceptibility indices were calculated using support vector machine by employing six types of kernel function classifiers. Subsequently, the results were plotted in ArcGIS and six landslide susceptibility maps were produced. Then, using the success rate and the prediction rate methods, the validation process was performed by comparing the existing landslide data with the six landslide susceptibility maps. The validation results showed that success rates for six types of kernel models varied from 79% to 87%. Similarly, results of prediction rates showed that RBF (85%) and polynomial degree of 3 (83%) models performed slightly better than other types of kernel (polynomial degree of 2 = 78%, sigmoid = 78%, polynomial degree of 4 = 78%, and linear = 77%) models. Based on our results, the differences in the rates (success and prediction) of the six models are not really significant. So, the produced susceptibility maps will be useful for general land-use planning. © Indian Academy of Sciences.

Mazloomi K.,University Putra Malaysia | Sulaiman N.B.,University Putra Malaysia | Moayedi H.,Islamic Azad University at Estahban
International Journal of Electrochemical Science | Year: 2012

Common industrial electrolyzers have a nominal hydrogen production efficiency of around 70%. High power dissipation value is the most important drawback of such systems since electric power expense has the largest share in the price of electrolytic hydrogen. The electrical impedance of an electrolysis cell causes a fraction of the applied energy to be wasted as heat while the electric current passes through it. As the prior publications show, many efforts are made to reduce this effect. According to the available literature, several internal and external variables are pointed out to have an influence on the electrical behavior of such cells. This paper provides an insight to these factors in regards to minimize the energy loss of the process of water electrolysis. © 2012 by ESG.

Yeganeh Ghotbi M.,University of Malayer | Bin Hussein M.Z.,University Putra Malaysia
Journal of Physics and Chemistry of Solids | Year: 2010

A new organic-clay material, in which the organic moiety is intercalated into the inorganic interlayer, was prepared using gallate anion (GA) as a guest, and Zn-Al-layered double hydroxide, as clay host. The ion-exchange technique was found to be effective for the intercalation process in the formation of the compound. Although the basal spacings of the LDH and its intercalated product were fairly similar, FTIR, CHNS and TGA/DTG results indicated that the GA was actually intercalated into the interlayer of the host in parallel orientation. The resulting nanostructure material possessed a well ordered layered structure with 42.2% GA loading (w/w). The release of the anion from the interlayer of the intercalated compound was found to be of controlled manner, governed by the first order kinetic and it was also concentration dependent. The material has potential as a nano-storage of anticarcenogenic agent with controlled delivery capability. © 2010 Elsevier Ltd. All rights reserved.

Abdullah U.H.B.,University of Lorraine | Abdullah U.H.B.,University Putra Malaysia | Pizzi A.,University of Lorraine
European Journal of Wood and Wood Products | Year: 2013

Tannin-furfuryl alcohol resins reacting under alcaline conditions to minimize self condensation of furfuryl alcohol and force its reaction with tannins have proved to be another alternative for formaldehyde free, environment friendly adhesives from renewable materials. © 2012 Springer-Verlag.

Abubakar B.S.U.I.,University Of Maiduguri | Ismail N.,University Putra Malaysia
ARPN Journal of Engineering and Applied Sciences | Year: 2012

The effectiveness of cow dung for biogas production was investigated, using a laboratory scale 10L bioreactor working in batch and semi-continuous mode at 53°C. Anaerobic digestion seemed feasible with an organic loading of up to 1.7 kg volatile solids (VS)/L d and an HRT of 10 days during the semi-continuous operation. The averaged cumulative biogas yield and methane content observed was 0.15 L/kg VS added and 47%, respectively. The TS, VS and COD removals amounted to 49%, 47% and 48.5%, respectively. The results of the VS/TS ratio showed very small variation, which denote adequate mixing performance. However there was some evidence of ammonia inhibition probably due to the uncontrolled pH employed. The data obtained establish that cow dung is an effective feedstock for biogas production achieving high cumulative biogas yield with stable performance. The future work will be carried out to study the effect of varying organic loading rate on anaerobic digestion of cow dung in a semi-continuous mode. © 2006-2012 Asian Research Publishing Network (ARPN).

Belkhiri L.,University of Batna | Narany T.S.,University Putra Malaysia
Water Resources Management | Year: 2015

Multivariate statistical analysis, geostatistical techniques and structural equation modeling were used to determine the main factors and mechanisms controlling the spatial variation of groundwater quality in the Ain Azel plain, Algeria. Cluster analysis grouped the sampling wells into two statistically significant clusters based on similarities of groundwater quality characteristics. Principal component and factor analyses (PCA/ FA) revealed that two factors explained around 85 % of the total variance, which water-rock interaction and anthropogenic impact as the dominant factors affecting the groundwater quality. The distribution of factor score one represents high loading for EC, Ca, Mg, Na, K, and SO4 in the western side and south eastern side of the plain, where water-rock interactions are dominate factors influence groundwater quality. Spatial distribution map of factor score 2 indicate that NO3, NO2, NH4, and COD show high concentration in central and southern side of the plain, where anthropogenic impact reduce groundwater quality. Further, one-way analysis of variance (one-way ANOVA) showed that the mean differences between cluster one and two show significantly differences for some water quality parameters including EC, Ca, Mg, Na, K, Cl, and SO4. Structural equation modeling (SEM) confirmed the finding of multivariate analysis. This study provides a new technique of confirming exploratory data analysis using SEM in groundwater quality. © 2015, Springer Science+Business Media Dordrecht.

Tien Bui D.,Norwegian University of Life Sciences | Tien Bui D.,Hanoi University of Mining and Geology | Pradhan B.,University Putra Malaysia | Lofman O.,Norwegian University of Life Sciences | And 2 more authors.
Catena | Year: 2012

The main objective of this study is to evaluate and compare the results of evidential belief functions and fuzzy logic models for spatial prediction of landslide hazards in the Hoa Binh province of Vietnam, using geographic information systems. First, a landslide inventory map showing the locations of 118 landslides that have occurred during the last ten years was constructed using data from various sources. Then, the landslide inventory was randomly partitioned into training and validation datasets (70% of the known landslide locations were used for training and building the landslide models and the remaining 30% for the model validation). Secondly, nine landslide conditioning factors were selected (i.e., slope, aspect, relief amplitude, lithology, landuse, soil type, distance to roads, distance to rivers and distance to faults). Using these factors, landslide susceptibility index values were calculated using evidential belief functions and fuzzy logic models. Finally, landslide susceptibility maps were validated and compared using the validation dataset that was not used in the model building. The prediction-rate curves and area under the curves were calculated to assess prediction capability. The results show that all the models have good prediction capabilities. The model derived using evidential belief functions has the highest prediction capability. The model derived using fuzzy SUM has the lowest prediction capability. The fuzzy PRODUCT and fuzzy GAMMA models have almost the same prediction capabilities. In general, all the models yield reasonable results that may be used for preliminary landuse planning purposes. © 2012 Elsevier B.V..

Shahriari E.,Shahrekord University | Mat Yunus W.M.,University Putra Malaysia | Zamiri R.,University of Aveiro
Journal of the European Optical Society | Year: 2013

A dual beam mode-mismatched thermal lens method has been employed to investigate the dependence of thermal diffusivity of gold nanofluid on nanoparticles sizes. The samples were prepared at various sizes by utilizing the gamma radiation method. In the dual beam mode-mismatched thermal lens a diode laser (532 nm) was used as an excitation beam and a He-Ne laser with the beam output at 632.8 nm was used as a probe beam. Thermal diffusivity of gold nano-fluid increased with the increasing particle sizes ranging from 10.4 to 29.6 nm.

Ghotbi M.Y.,University of Malayer | Bin Hussein M.Z.,University Putra Malaysia
Journal of Physics and Chemistry of Solids | Year: 2012

Immobilization of gallate anion, an anti-carcinogenic, anti-mutagenic, and anti-microbial agent on the surface of magnetite nanoparticles was accomplished by adsorption technique for the formation of a core-shell nanocomposite. A simple co-precipitation technique in the presence of poly vinyl pyrrolidone was successfully applied for the preparation of magnetite nanoparticles as core beads with narrow size distribution. The powders were characterized by X-ray diffraction, particle size analysis, magnetic measurements, atomic force microscope and also infrared spectroscopy. FTIR and CHNS results indicated that the gallate anion was actually adsorbed onto the surface of the magnetite nanoparticles. The release of the anion from the surface of the nanocomposite was found to be controllable by the selection of the release media. © 2012 Elsevier Ltd.

Tien Bui D.,Norwegian University of Life Sciences | Tien Bui D.,Hanoi University of Mining and Geology | Pradhan B.,University Putra Malaysia | Lofman O.,Norwegian University of Life Sciences | And 2 more authors.
Geomorphology | Year: 2012

This study investigates the potential application of artificial neural networks in landslide susceptibility mapping in the Hoa Binh province of Vietnam. A landslide inventory map of the study area was prepared by combining landslide locations investigated through three projects during the last 10. years. Some recent landslide locations were identified based on SPOT satellite images, field surveys, and existing literature. The images have a spatial resolution of 2.5. m. Ten landslide conditioning factors were utilized in the multilayer feed-forward neural network analysis: slope, aspect, relief amplitude, lithology, land use, soil type, rainfall, distance to roads, distance to rivers and distance to faults. Two back-propagation training algorithms, Levenberg-Marquardt and Bayesian regularization, were utilized to determine synoptic weights using a training dataset. Relative importance of each landslide conditioning factor was assessed using the above mentioned synoptic weights. The final connection weights obtained in the training phase were applied to the entire study area to produce landslide susceptibility indexes. The results were then imported to a GIS and landslide susceptibility maps were constructed. Landslide locations not used in the training phase were used to verify and compare the results of the landslide susceptibility maps. Finally, the two landslide susceptibility maps were validated using the prediction-rate method. Subsequently, areas under the prediction curves were assessed. The prediction accuracy of landslide susceptibility maps produced by the Bayesian regularization neural network and the Levenberg-Marquardt neural network were 90.3% and 86.1% respectively. These results indicate that the two models seem to have good predictive capability. The Bayesian regularization network model appears more robust and efficient than the Levenberg-Marquardt network model for landslide susceptibility mapping. © 2012 Elsevier B.V.

Ahmad S.,University Putra Malaysia | Ahmad S.,University Malaysia Perlis | Kadir M.Z.A.A.,University Putra Malaysia | Shafie S.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2011

It is estimated that oil reserves will not last very much longer; thus, a switch to alternative energy solutions is crucial. The Malaysian government has already prepared to face the situation decades before. Many policies have been implemented, as well as programmes and initiative. Now, Malaysia is waiting for the ultimate solutions, the Malaysian Fit-in Tariff (FiT), which is scheduled to be implemented second quarter of 2011. This paper presents the main sources of alternative renewable energy in Malaysia and its potential as well as the main reasons Malaysia is turning to alternative energy solutions; to fully utilize its renewable energy (RE) resources, fulfill the energy demand in the future and to reduce carbon emissions. This paper also discusses the steps taken by the government in preparation for FiT and overcoming the barriers in RE development. © 2010 Elsevier Ltd. All rights reserved.

Huang X.D.,Lanzhou University | Tan H.Y.,University Putra Malaysia | Long R.,Lanzhou University | Liang J.B.,University Putra Malaysia | Wright A.-D.G.,University of Vermont
BMC Microbiology | Year: 2012

Background: Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from energy-saving animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. Results: Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. Conclusion: This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle, this may also help to explain why yak produce less methane than cattle. © 2012 Huang et al.; licensee BioMed Central Ltd.

Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University
Natural Hazards | Year: 2012

The main goal of this study is to produce landslide susceptibility maps of a landslide-prone area (Haraz) in Iran by using both fuzzy logic and analytical hierarchy process (AHP) models. At first, landslide locations were identified by aerial photographs and field surveys, and a total of 78 landslides were mapped from various sources. Then, the landslide inventory was randomly split into a training dataset 70 % (55 landslides) for training the models and the remaining 30 % (23 landslides) was used for validation purpose. Twelve data layers, as the landslide conditioning factors, are exploited to detect the most susceptible areas. These factors are slope degree, aspect, plan curvature, altitude, lithology, land use, distance from rivers, distance from roads, distance from faults, stream power index, slope length, and topographic wetness index. Subsequently, landslide susceptibility maps were produced using fuzzy logic and AHP models. For verification, receiver operating characteristics curve and area under the curve approaches were used. The verification results showed that the fuzzy logic model (89. 7 %) performed better than AHP (81. 1 %) model for the study area. The produced susceptibility maps can be used for general land use planning and hazard mitigation purpose. © 2012 Springer Science+Business Media B.V.

Pourghasemi H.R.,Tarbiat Modares University | Mohammady M.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia
Catena | Year: 2012

Landslide susceptibility mapping is essential for land use planning and decision-making especially in the mountainous areas. The main objective of this study is to produce landslide susceptibility maps at Safarood basin, Iran using two statistical models such as an index of entropy and conditional probability and to compare the obtained results. At the first stage, landslide locations were identified in the study area by interpretation of aerial photographs and from field investigations. Of the 153 landslides identified, 105 (≈. 70%) locations were used for the landslide susceptibility maps, while the remaining 48 (≈. 30%) cases were used for the model validation. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, distance to faults, distance to rivers, distance to roads, topographic wetness index (TWI), stream power index (SPI), slope-length (LS), land use, and plan curvature were extracted from the spatial database. Using these factors, landslide susceptibility and weights of each factor were analyzed by index of entropy and conditional probability models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and the areas under the curve (AUC) were calculated. The verification results showed that the index of entropy model (AUC. =. 86.08%) performed slightly better than conditional probability (AUC. =. 82.75%) model. The produced susceptibility maps can be useful for general land use planning in the Safarood basin, Iran. © 2012 Elsevier B.V.

Islam A.,Universiti Malaysia Sabah | Taufiq-Yap Y.H.,University Putra Malaysia | Chu C.-M.,Universiti Malaysia Sabah | Chan E.-S.,University of Selangor | Ravindra P.,Universiti Malaysia Sabah
Process Safety and Environmental Protection | Year: 2013

The production of biodiesel is gaining momentum with the ever increasing demand of the fuel. Presently, limited literature is available with respect to well designed solid heterogeneous catalyst for biodiesel production considering all the characteristics, process and operation parameters. Hence, a study was conducted to design effective heterogeneous catalyst for biodiesel production. Further, the significant impact of different catalysts, different feed stock, various reaction conditions such as temperature, methanol oil molar ratio, catalyst concentrations and stability/inactivation of the catalysts, are detailed out for transesterification process of biodiesel production. Based on the studies it can be concluded that well designed heterogeneous catalyst can yield high throughput of biodiesel. © 2012 The Institution of Chemical Engineers.

Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University | Moezzi K.D.,B. Science graduate of environment
Geomatics, Natural Hazards and Risk | Year: 2013

In a country with diverse geologic, topographic and climatic conditions such as Iran, landslides are frequent phenomena. The aim of this study is to perform a landslide susceptibility assessment at Haraz watershed, Iran using two different approaches such as Dempster-Shafer and Weights-of-evidence models in GIS. First, a landslide inventory map was prepared using the landslide occurrence data by interpreting aerial photographs and field surveys. Second, thematic maps including lithology, altitude, and land-use are prepared in GIS. A total 11 landslide conditioning factors are considered such as slope angle, aspect, altitude, distance from drainage, distance from road, distance from river, lithology, land use, topographic wetness index, stream power index and slope-length (LS). The relationship between the conditional factors and the landslides were calculated using both Dempster-Shafer and Weights-of-evidence models. Using the predicted values, landslide susceptibility maps of the study area is produced. For verification, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curves for all landslide susceptibility models were drawn and the area under curve values was calculated. The AUC value of the produced landslide susceptibility maps has been obtained as 72.87% and 79.87% for Dempster-Shafer and Weights-of-evidence models, respectively. The resulting susceptibility maps would be useful for landuse planning and prioritization of efforts for the reduction and mitigation of future landslide hazards in Haraz watershed. © 2013 Copyright Taylor and Francis Group, LLC.

Mohammady M.,Tarbiat Modares University | Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia
Journal of Asian Earth Sciences | Year: 2012

The purpose of the present study is to investigate the landslide susceptibility mapping using three statistical models such as frequency ratio, Dempster-Shafer, and weights-of-evidence at southern part of Golestan province. At first, landslide locations were identified from the interpretation of aerial photographs, and field surveys. A total of 392 landslides were mapped in GIS out of which 275 (70%) locations were chosen for the modeling purpose and the remaining 118 (30%) cases were used for the model validation. Then layers of the landslide conditioning factors were prepared. The relationship between the conditioning factors and the landslides were calculated using three models. For verification, the results were compared with landslides which were not used during the training of the models. Subsequently, the ROC (Receiver operating characteristic) curves and area under the curves (AUC) for three landslide susceptibility maps were constructed and the areas under curves were assessed for validation purpose. The validation results showed that the area under the curve for frequency ratio, Dempster-Shafer, and weights-of-evidence models are 0.8013 (80.13%), 0.7832 (78.32%), and 0.7460 (74.60%) with prediction accuracy 0.7516 (75%), 0.7396 (73%), and 0.6998 (69%) respectively. The results revealed that frequency ratio model has higher AUC than the other models. In general, all the three models produced reasonable accuracy. The resultant maps would be useful for general land use planning. © 2012 Elsevier Ltd.

Majeed K.,University of Technology Malaysia | Majeed K.,COMSATS Institute of Information Technology | Jawaid M.,University Putra Malaysia | Hassan A.,University of Technology Malaysia | And 4 more authors.
Materials and Design | Year: 2013

The increasing demand for new food packaging materials which satisfy people requirements provided thrust for advancement of nano-materials science. Inherent permeability of polymeric materials to gases and vapours; and poor barrier and mechanical properties of biopolymers have boosted interest in developing new strategies to improve these properties. Research and development in polymeric materials coupled with appropriate filler, matrix-filler interaction and new formulation strategies to develop composites have potential applications in food packaging. Advancement in food packaging materials expected to grow with the advent of cheap, renewable and sustainable materials with enhanced barrier and mechanical properties. Nanoparticles have proportionally larger surface area and significant aspect ratio than their micro-scale counterparts, which promotes the development of mechanical and barrier properties. Nanocomposites are attracting considerable interest in food packaging because of these fascinating features. On the other hand, natural fibres are susceptible to microorganisms and their biodegradability is one of the most promising aspects of their incorporation in polymeric materials. Present review article explain about different categories of nanoclay and natural fibre based composite with particular regard to its applications as packaging materials and also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of hybrid composites for environmentally compatible food packaging materials. © 2012 Elsevier Ltd.

Lim S.A.H.,Manufacture and Engineering Management | Lim S.A.H.,University Putra Malaysia | Antony J.,Manufacture and Engineering Management | Albliwi S.,Manufacture and Engineering Management
Trends in Food Science and Technology | Year: 2014

This paper presents a systematic review on the reported implementation of Statistical Process Control (SPC) in the food industry. The final selection comprehends 41 articles selected and comprehensively analysed to assess SPC development in the food industry through its motivations, benefits, challenges and limitations. Key outputs indicated from the review include: reduced process variability and conformance to the food regulations are the biggest motivations; resistance to accept SPC is the most cited challenge; lack of statistical knowledge is the most common limitation and the biggest benefits for implementing SPC in the food industry are improved food safety and reduced process variation. © 2014 Elsevier Ltd.

Chin M.J.,University of Selangor | Poh P.E.,University of Selangor | Tey B.T.,University of Selangor | Chan E.S.,University of Selangor | Chin K.L.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

The generation of palm oil mill effluent (POME) alongside with the production of crude palm oil has created environmental issue for the palm oil mill industry in Malaysia due to its polluting characteristics. POME with its high organic content is a source with great potential for biogas production. However, POME is commonly treated using open ponding system just to comply with government regulation without capturing biogas released from the process. Biogas generated from anaerobic digestion of POME can replace palm kernel shell and mesocarp fiber which has higher economic value as boiler fuel; upgraded to be used in gas engine for power generation. It is estimated that net profit of RM 3.8 million per year can be obtained in a palm oil mill with processing capacity of 60 tonnes/hr from electricity generation using biogas produced from POME treatment. This review paper will elaborate on the potential of POME as a source of renewable energy and the challenges faced by the palm oil mills in Malaysia which deters the development of biogas plants in the mill. © 2013 Elsevier Ltd.

Ahmad Z.A.,University Putra Malaysia | Yeap S.K.,University Putra Malaysia | Ali A.M.,Darul Iman University, Malaysia | Ho W.Y.,University Putra Malaysia | And 2 more authors.
Clinical and Developmental Immunology | Year: 2012

To date, generation of single-chain fragment variable (scFv) has become an established technique used to produce a completely functional antigen-binding fragment in bacterial systems. The advances in antibody engineering have now facilitated a more efficient and generally applicable method to produce Fv fragments. Basically, scFv antibodies produced from phage display can be genetically fused to the marker proteins, such as fluorescent proteins or alkaline phosphatase. These bifunctional proteins having both antigen-binding capacity and marker activity can be obtained from transformed bacteria and used for one-step immunodetection of biological agents. Alternatively, antibody fragments could also be applied in the construction of immunotoxins, therapeutic gene delivery, and anticancer intrabodies for therapeutic purposes. This paper provides an overview of the current studies on the principle, generation, and application of scFv. The potential of scFv in breast cancer research is also discussed in this paper. Copyright 2012 Zuhaida Asra Ahmad et al.

Pourghasemi H.R.,Tarbiat Modares University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University
Applied Mechanics and Materials | Year: 2012

In recent years, the growth of urban populations in hazardous areas has increased the impact of natural disasters in both developed and developing countries. The purpose of the current study is to assess the landslide susceptibility in Kalaleh township of Golestan province, Iran. In this study the Shannon's entropy approach was applied. A total of 82 landslide locations were identified primarily from aerial photographs and field surveys. Then eighteen landslides conditioning factors were prepared in GIS. These landslide conditioning factors are: slope degree, slope aspect, altitude, plan curvature, profile curvature, tangential curvature, surface area ratio (SAR), lithology, land use, soil texture, distance from faults, distance from rivers, distance from roads, fault density, road density, topographic wetness index (TWI), stream power index (SPI), and sediment transport index (STI). Using these conditioning factors, landslide susceptibility index was calculated using Shannon's entropy. For model validation, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curves for landslide susceptibility maps were drawn and the area under curve values was calculated. Verification results showed 82.15% accuracy. According to the results of the AUC (area under curve) evaluation, the map produced exhibits satisfactory properties. © (2012) Trans Tech Publications, Switzerland.

Wen T.N.,University Putra Malaysia | Prasad K.N.,University Putra Malaysia | Yang B.,CAS South China Botanical Garden | Ismail A.,University Putra Malaysia
Innovative Food Science and Emerging Technologies | Year: 2010

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389-539 μg/100 g), blanched (510-818 μg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2-7.8 mg/100 g), blanched (0.67-3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene. Industrial relevance: Beans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work. © 2009 Elsevier Ltd. All rights reserved.

Islam A.,Universiti Malaysia Sabah | Islam A.,University Putra Malaysia | Taufiq-Yap Y.H.,University Putra Malaysia | Chu C.-M.,Universiti Malaysia Sabah | And 2 more authors.
Renewable Energy | Year: 2013

The use of spherical millimetric gamma-alumina (γ-Al2O3) as a catalyst support for the production of biodiesel from palm oil is demonstrated. The catalyst support was produced using a dripping method, and KF and NaNO3 catalysts were loaded on the support using the impregnation method. X-ray diffraction (XRD) analysis showed the formation of Na2O and NaAlO2 phases on the NaNO3/γ-Al2O3 catalyst and the formation of K2O and KAlF4 on the KF/γ-Al2O3 catalyst, which were possibly the active sites for the transesterification reaction. The highest number and strength of basic sites generated from the solid phase reaction of the KF/γ-Al2O3 catalyst loaded with 0.24g kF/g γ-Al2O3 and the NaNO3/γ-Al2O3 catalyst loaded with 0.30g NaNO3/g γ-Al2O3 were confirmed by temperature programmed desorption of CO2 (CO2-TPD) analysis. The nitrogen adsorption-desorption isotherms also revealed a mesoporous structure of the catalysts. The biodiesel yield was comparable to that produced from smaller catalysts, and this result indicated the potential of the macrospherical catalysts. © 2013 Elsevier Ltd.

Sezer E.A.,Hacettepe University | Pradhan B.,University Putra Malaysia | Gokceoglu C.,Hacettepe University
Expert Systems with Applications | Year: 2011

The purpose of the present paper is to manifest the results of the neuro-fuzzy model using remote sensing data and GIS for landslide susceptibility analysis in a part of the Klang Valley areas i Malaysia. Landslide locations in the study area were identified by interpreting aerial photographs and satellite images, supported by extensive field surveys. SPOT 5 satellite imagery was used to map vegetation index. Maps of topography, lineaments, NDVI and land cover were constructed from the spatial datasets. Seven landslide conditioning factors such as altitude, slope angle, plan curvature, distance from drainage, soil type, distance from faults and NDVI were extracted from the spatial database. These factors were analyzed using a neuro-fuzzy model (adaptive neuro-fuzzy inference system, ANFIS) to construct the landslide susceptibility maps. During the model development works, total 5 landslide susceptibility models were obtained by using ANFIS results. For verification, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the ROC curves for all landslide susceptibility models were drawn and the area under curve values was calculated. Landslide locations were used to validate results of the landslide susceptibility map and the verification results showed 98% accuracy for the model 5 employing all parameters produced in the present study as the landslide conditioning factors. The validation results showed sufficient agreement between the obtained susceptibility map and the existing data on landslide areas. Qualitatively, the model yields reasonable results which can be used for preliminary landuse planning purposes. As a conclusion, the ANFIS is a very useful tool for regional landslide susceptibility assessments. © 2011 Elsevier Ltd. All rights reserved.

Ismail M.,Institute of Bioscience | Ismail M.,University Putra Malaysia | Al-Naqeep G.,Institute of Bioscience | Al-Naqeep G.,University Putra Malaysia | Chan K.W.,Institute of Bioscience
Free Radical Biology and Medicine | Year: 2010

The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH ·)-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH · compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P < 0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P < 0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats. © 2009 Elsevier Inc. All rights reserved.

Loh Y.F.,University Putra Malaysia | Paridah M.T.,University Putra Malaysia | Hoong Y.B.,Fibre and Biocomposite Development Center | Choo A.C.Y.,University Putra Malaysia
Materials and Design | Year: 2011

Even though oil palm (Elaeis quineensis) stem (OPS) is highly potential as an alternative raw material in wood industry, it possesses some inferior characteristics. One of the critical weaknesses is a high degree of veneer surface roughness that resulted in high resin consumption during plywood manufacture. The objective of this study was to investigate effects of treatment with low molecular weight phenol formaldehyde (LMWPF) resin on the wettability and surface roughness of OPS veneer. OPS veneers were segregated into two categories namely outer and inner layer veneer, prior to soaking in LMWPF resin solution to obtain weight percent gain of 16-20%. The wettability of OPS veneers was assessed with contact angle measurement according to the sessile drop method. The veneer surface roughness was evaluated by determining the average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) using a stylus profilometer in accordance with DIN standard 4768. The results show that the effect of LMWPF resin treatment on the surface roughness of the veneers is statistically significant. The technique used in the study was able to enhance the surface properties as well as improved the physical and mechanical properties of OPS plywood. © 2010 Elsevier Ltd.

Ibrahim M.H.,University of Kuala Lumpur | Law S.H.,University Putra Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

The present paper examines the mitigating effect of social capital on the environmental Kuznets curve (EKC) for CO2 emissions using a panel data of 69 developed and developing countries. Adopting generalised method of moments (GMM) estimators, the paper finds evidence substantiating the presence of EKC. Moreover, the evidence suggests that the pollution costs of economic development tend to be lower in countries with higher social capital reservoir. Surprisingly, there is also evidence to indicate that the income threshold point beyond which CO2 emissions decline is higher in countries with higher social capital. These results are robust to addition of alternative controlled variables in the EKC specification. Thus, in addition to policy focus on investments in environmentally friendly technology and on the use of renewable energy, investments in social capital can also mitigate the pollution effects of economic progress. © 2013 Elsevier Ltd.

Parvaneh K.,University Putra Malaysia | Jamaluddin R.,University Putra Malaysia | Karimi G.,University Putra Malaysia | Erfani R.,University of Kuala Lumpur
The Scientific World Journal | Year: 2014

A few studies in animals and a study in humans showed a positive effect of probiotic on bone metabolism and bone mass density. Most of the investigated bacteria were Lactobacillus and Bifidobacterium. The positive results of the probiotics were supported by the high content of dietary calcium and the high amounts of supplemented probiotics. Some of the principal mechanisms include (1) increasing mineral solubility due to production of short chain fatty acids; (2) producing phytase enzyme by bacteria to overcome the effect of mineral depressed by phytate; (3) reducing intestinal inflammation followed by increasing bone mass density; (4) hydrolysing glycoside bond food in the intestines by Lactobacillus and Bifidobacteria. These mechanisms lead to increase bioavailability of the minerals. In conclusion, probiotics showed potential effects on bone metabolism through different mechanisms with outstanding results in the animal model. The results also showed that postmenopausal women who suffered from low bone mass density are potential targets to consume probiotics for increasing mineral bioavailability including calcium and consequently increasing bone mass density. © 2014 Kolsoom Parvaneh et al.

Bordbar S.,University Putra Malaysia | Anwar F.,University Putra Malaysia | Anwar F.,University of Agriculture at Faisalabad | Saari N.,University Putra Malaysia
Marine Drugs | Year: 2011

Sea cucumbers, belonging to the class Holothuroidea, are marine invertebrates, habitually found in the benthic areas and deep seas across the world. They have high commercial value coupled with increasing global production and trade. Sea cucumbers, informally named as bêche-de-mer, or gamat, have long been used for food and folk medicine in the communities of Asia and Middle East. Nutritionally, sea cucumbers have an impressive profile of valuable nutrients such as Vitamin A, Vitamin B1 (thiamine), Vitamin B2 (riboflavin), Vitamin B3 (niacin), and minerals, especially calcium, magnesium, iron and zinc. A number of unique biological and pharmacological activities including anti-angiogenic, anticancer, anticoagulant, anti-hypertension, anti-inflammatory, antimicrobial, antioxidant, antithrombotic, antitumor and wound healing have been ascribed to various species of sea cucumbers. Therapeutic properties and medicinal benefits of sea cucumbers can be linked to the presence of a wide array of bioactives especially triterpene glycosides (saponins), chondroitin sulfates, glycosaminoglycan (GAGs), sulfated polysaccharides, sterols (glycosides and sulfates), phenolics, cerberosides, lectins, peptides, glycoprotein, glycosphingolipids and essential fatty acids. This review is mainly designed to cover the high-value components and bioactives as well as the multiple biological and therapeutic properties of sea cucumbers with regard to exploring their potential uses for functional foods and nutraceuticals. © 2011 by the authors; licensee MDPI.

Atangana A.,University of the Free State | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

Fractional advection-dispersion equations are used in groundwater hydrology to model the transport of passive tracers carried by fluid flow in porous medium. A space-time fractional advection-dispersion equation (FADE) is a generalization of the classical ADE in which the first-order space derivative is replaced with Caputo or Riemann-Liouville derivative of order 0 < β ≤ 1, and the second-order space derivative is replaced with the Caputo or the Riemann-Liouville fractional derivative of order 1 < ≤ 2. We derive the solution of the new equation in terms of Mittag-Leffler functions using Laplace transfrom. Some examples are given. The results from comparison let no doubt that the FADE is better in prediction than ADE. © 2013 Abdon Atangana and Adem Kilicman.

Atangana A.,University of the Free State | Kilicman A.,University Putra Malaysia
Mathematical Problems in Engineering | Year: 2013

The standard version of acoustic wave equation is modified using the concept of the generalized Riemann-Liouville fractional order derivative. Some properties of the generalized Riemann-Liouville fractional derivative approximation are presented. Some theorems are generalized. The modified equation is approximately solved by using the variational iteration method and the Green function technique. The numerical simulation of solution of the modified equation gives a better prediction than the standard one. © 2013 Abdon Atangana and Adem Kiliçman.

Kadem A.,Ferhat Abbas University Setif | Klman A.,University Putra Malaysia
Computers and Mathematics with Applications | Year: 2011

In this paper, the Chebyshev polynomials to solve analytically the fractional neutron transport equation in one-dimensional plane geometry are used. The procedure is based on the expansion of the angular flux in terms of the Chebyshev polynomials. The obtained system of fractional linear differential equation is solved analytically by using fractional Sumudu transform. © 2011 Elsevier Ltd. All rights reserved.

Narzullaev A.,University Putra Malaysia | Park Y.,Yeungnam University
AEU - International Journal of Electronics and Communications | Year: 2013

Fingerprinting is a popular technology for indoor WLAN based locating systems. Received signal strength information from different access points is used to estimate the location of mobile users. One of the drawbacks of fingerprinting algorithm is the extensive and time-consuming calibration (training) phase, during which the received signal strength measurements from nearby wireless access points are gathered at pre-defined reference spots and stored in a database to build a prior radio signal strength map of the region. In this manuscript, we present a new, precise and time efficient calibration algorithm that combines the reference data collection procedure with the path-loss prediction model. Our algorithm requires only a few samples to be measured in a given region, and thus significantly reduces the calibration time; the rest of the signal strength database is then estimated by using path-loss prediction model. We carefully evaluate the proposed algorithm through a real-world experiment. Field test results show that our new approach reduces the calibration time without harming the location accuracy of the locating system. © 2012 Elsevier GmbH.

Abazari R.,Islamic Azad University at Ardabil | Kilicman A.,University Putra Malaysia
Neural Computing and Applications | Year: 2014

In this work, we applied the differential transform method, by presenting and proving some theorems, to solve the nonlinear integro-differential equation with proportional delays. This technique provides a sequence of functions which converges to the exact solution of the problem. In order to show the power and the robustness of the method and to illustrate the pertinent features of related theorems, some examples are presented. © 2012 Springer-Verlag London.

Nazarpour F.,University Putra Malaysia | Abdullah D.K.,University Putra Malaysia | Abdullah N.,University Putra Malaysia | Zamiri R.,University of Aveiro
Materials | Year: 2013

The effects of biological pretreatment on the rubberwood (Hevea brasiliensis), was evaluated after cultivation of white rot fungi Ceriporiopsis subvermispora, Trametes versicolor, and a mixed culture of C. subvermispora and T. versicolor. The analysis of chemical compositions indicated that C. subvermispora had greater selectivity for lignin degradation with the highest lignin and hemicellulose loss at 45.06% and 42.08%, respectively, and lowest cellulose loss (9.50%) after 90 days among the tested samples. X-ray analysis showed that pretreated samples had a higher crystallinity than untreated samples. The sample pretreated by C. subvermispora presented the highest crystallinity of all the samples which might be caused by the selective degradation of amorphous components. Fourier transform infrared (FT-IR) spectroscopy demonstrated that the content of lignin and hemicellulose decreased during the biological pretreatment process. A study on hydrolysis of rubberwood treated with C. subvermispora, T. versicolor, and mixed culture for 90 days resulted in an increased sugar yield of about 27.67%, 16.23%, and 14.20%, respectively, as compared with untreated rubberwood (2.88%). The results obtained demonstrate that rubberwood is a potential raw material for industrial applications and white rot fungus C. subevermispora provides an effective method for improving the enzymatic hydrolysis of rubberwood. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

El-Shekeil Y.A.,University Putra Malaysia | Sapuan S.M.,University Putra Malaysia | Jawaid M.,University Putra Malaysia | Al-Shuja'a O.M.,Thamar University
Materials and Design | Year: 2014

Kenaf (Hibiscus Cannabinus) bast fiber reinforced poly(vinyl chloride) (PVC)/thermoplastic polyurethane (TPU) poly-blend was prepared by melt mixing method using Haake Polydrive R600 internal mixer. The composites were prepared with different fiber content: 20%, 30% and 40% (by weight), with the processing parameters: 140°C, 11min, and 40rpm for temperature, time and speed, respectively. After mixing, the composite was compressed using compressing molding machine. Mechanical properties (i.e. tensile properties, flexural properties, impact strength) were studied. Morphological properties of tensile fracture surface were studied using Scanning electron microscope (SEM). Thermal properties of the composites were studied using Thermogravimetric Analyses (TGA). PVC/TPU/KF composites have shown lower tensile strength and strain with increase in fiber content. Tensile modulus showed an increasing trend with increase in fiber content. Impact strength decreased with increase in fiber content; however, high impact strength was observed even with 40% fiber content (20.2kJ/m2). Mean while; the 20% and 30% fiber contents showed higher impact strength of 34.9, 27.9kJ/m2; respectively. SEM showed that there is poor fiber/matrix adhesion. Thermal degradation took place in three steps. In the first step, composites as well as the matrix had a similar stability. At the second step, matrix showed a slightly better stability than the composites. At the last step, composites showed a better stability than the matrix. © 2014 Elsevier Ltd.

Karim A.A.,Cocoa Innovation and Technology Center | Azlan A.,University Putra Malaysia
Molecules | Year: 2012

Fruit pods contain various beneficial compounds that have biological activities and can be used as a source of pharmaceutical and nutraceutical products. Although pods or pericarps are usually discarded when consuming the edible parts of fruits, they contain some compounds that exhibit biological activities after extraction. Most fruit pods included in this review contain polyphenolic components that can promote antioxidant effects on human health. Additionally, anti-inflammatory, antibacterial, antifungal and chemopreventive effects are associated with these fruit pod extracts. Besides polyphenolics, other compounds such as xanthones, carotenoids and saponins also exhibit health effects and can be potential sources of nutraceutical and pharmaceutical components. In this review, information on fruit pods or pericarp of Garcinia mangostana, Ceratonia siliqua, Moringa oleifera, Acacia nilotica, Sapindus rarak and Prosopis cineraria is presented and discussed with regard to their biological activity of the major compounds existing in them. The fruit pods of other ethno-botanical plants have also been reviewed. It can be concluded that although fruit pods are considered as being of no practical use and are often being thrown away, they nevertheless contain compounds that might be useful sources of nutraceutical and other pharmaceutical components. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Loo Y.Y.,University Putra Malaysia | Chieng B.W.,University Putra Malaysia | Nishibuchi M.,Kyoto University | Radu S.,University Putra Malaysia
International Journal of Nanomedicine | Year: 2012

The development of the biological synthesis of nanoparticles using microorganisms or plant extracts plays an important role in the field of nanotechnology as it is environmentally friendly and does not involve any harmful chemicals. In this study, the synthesis of silver nanoparticles using the leaves extract of Chinese tea from Camellia sinensis is reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized silver nanoparticles are of face-centered cubic structure. Well-dispersed silver nanoparticles with an approximate size of 4 nm were observed in the TEM image. The application of the green synthesized nanoparticles can be used in many fields such as cosmetics, foods, and medicine. © 2012 Loo et al, publisher and licensee Dove Medical Press Ltd.

Ismail H.I.,University Putra Malaysia | Chan K.W.,Institute of Bioscience | Mariod A.A.,Institute of Bioscience | Ismail M.,University Putra Malaysia | Ismail M.,Institute of Bioscience
Food Chemistry | Year: 2010

The objectives of this study were to determine phenolic content and antioxidant activity of methanolic extracts from different parts of cantaloupe (leaf, stem, skin, seed and flesh). The flesh extract afforded the highest yield (89.6 ± 0.3%) whilst the lowest yield was obtained from the seed (13.7 ± 0.5%) (p < 0.05). The leaf extract showed the highest total phenolic content (26.4 ± 0.3 mg GAE/g extract) and total flavonoid content (69.7 ± 3.37 μg RE/g extract) accompanied with best antioxidant activity through all antioxidant assays (p < 0.05). In addition, the stem extract also exhibited good antioxidant activity. Thus, these results suggest that methanolic extracts of cantaloupe leaf and stem may serve as a potential source of natural antioxidant for food and nutraceutical application. © 2009 Elsevier Ltd. All rights reserved.

Nakyinsige K.,University Putra Malaysia | Nakyinsige K.,Islamic University in Uganda | Man Y.B.C.,University Putra Malaysia | Sazili A.Q.,University Putra Malaysia
Meat Science | Year: 2012

In the recent years, Muslims have become increasingly concerned about the meat they eat. Proper product description is very crucial for consumers to make informed choices and to ensure fair trade, particularly in the ever growing halal food market. Globally, Muslim consumers are concerned about a number of issues concerning meat and meat products such as pork substitution, undeclared blood plasma, use of prohibited ingredients, pork intestine casings and non-halal methods of slaughter. Analytical techniques which are appropriate and specific have been developed to deal with particular issues. The most suitable technique for any particular sample is often determined by the nature of the sample itself. This paper sets out to identify what makes meat halal, highlight the halal authenticity issues that occur in meat and meat products and provide an overview of the possible analytical methods for halal authentication of meat and meat products. © 2012 Elsevier Ltd.

Hashim J.H.,University of Kuala Lumpur | Hashim Z.,University Putra Malaysia
Asia-Pacific Journal of Public Health | Year: 2014

The Asia Pacific region is regarded as the most disaster-prone area of the world. Since 2000, 1.2 billion people have been exposed to hydrometeorological hazards alone through 1215 disaster events. The impacts of climate change on meteorological phenomena and environmental consequences are well documented. However, the impacts on health are more elusive. Nevertheless, climate change is believed to alter weather patterns on the regional scale, giving rise to extreme weather events. The impacts from extreme weather events are definitely more acute and traumatic in nature, leading to deaths and injuries, as well as debilitating and fatal communicable diseases. Extreme weather events include heat waves, cold waves, floods, droughts, hurricanes, tropical cyclones, heavy rain, and snowfalls. Globally, within the 20-year period from 1993 to 2012, more than 530 000 people died as a direct result of almost 15 000 extreme weather events, with losses of more than US$2.5 trillion in purchasing power parity. © Asia-Pacific Academic Consortium for Public Health.

Rikhsiboev I.M.,University of Kuala Lumpur | Rakhimov I.S.,University Putra Malaysia
AIP Conference Proceedings | Year: 2012

The aim of this paper is to complete the classification of three-dimensional complex Leibniz algebras. The description of isomorphism classes of three-dimensional complex Leibniz algebras has been given by Ayupov and Omirov in 1999. However, we found that this list has a little redundancy. In this paper we apply a method which is more elegant and it gives the precise list of isomorphism classes of these algebras. We compare our list with that of Ayupov-Omirov and show the corrections which should be made. © 2012 American Institute of Physics.

Selvarajah G.T.,University Utrecht | Selvarajah G.T.,University Putra Malaysia | Kirpensteijn J.,University Utrecht
Veterinary Journal | Year: 2010

Canine osteosarcoma (OS) is an aggressive tumour that accounts for approximately 90% of primary bone tumours in the dog. Although the standard treatments (including limb amputation/sparing, chemotherapy and palliative radiotherapy) have significantly increased survival rates, almost 90% of animals will eventually develop predominantly pulmonary metastases. Despite advances in various therapies, prognosis remains poor, with median survival times ranging from 3. months to 1. year and <20% of dogs survive for >2. years following diagnosis.Various clinical and epidemiological markers have facilitated decision-making with respect to therapy but no single molecular biomarker has been shown to enhance prediction of disease progression. The publication of the canine genome in 2005 raised the possibility of increasing understanding of the genetic mechanisms underpinning canine OS. This review explores the use of biomarkers within the multi-disciplinary management of dogs with OS, and highlights the few known, potential prognostic/predictive molecular markers including their potential value as 'bridging biomarkers' for human OS. Although high-throughput profiling of canine OS remains in its infancy, research within the next decade using leading-edge screening technologies has the potential to identify biomarkers that may enhance diagnostic and prognostic accuracy and result in more effective, individually tailored, treatment and management protocols for affected dogs. © 2010 Elsevier Ltd.

Abdul Khalil H.P.S.,Universiti Sains Malaysia | Bhat I.U.H.,Universiti Sains Malaysia | Jawaid M.,University of Technology Malaysia | Zaidon A.,University Putra Malaysia | And 2 more authors.
Materials and Design | Year: 2012

The reduction in harmful destruction of ecosystem and to produce low cost polymeric reinforced composites, the researchers are emerging with policies of manufacturing the composites using natural fibres which are entirely biodegradable. These policies had generated safe strategies to protect our environment. The utilization of bamboo fibres as reinforcement in composite materials has increased tremendously and has undergone high-tech revolution in recent years as a response to the increasing demand for developing biodegradable, sustainable, and recyclable materials. The amalgamation of matrix and natural fibres yield composite possessing best properties of each component. Various matrices used currently are soft and flexible in comparison to natural fibres their combination leads to composite formation with high strength-to-weight ratios. The rapid advancement of the technology for making industry products contributes consumer the ease of making a suitable choice and own desirable tastes. Researchers have expanded their expertise in the product design by applying the usage of raw materials like bamboo fibre which is stronger as well as can be utilized in generating high end quality sustainable industrial products. Thereby, this article gives critical review of the most recent developments of bamboo fibre based reinforced composites and the summary of main results presented in literature, focusing on the processing methodology and ultimate properties of bamboo fibres with polymeric matrices and applications in well designed economical products. © 2012 Elsevier Ltd.

Al-Shookri A.,Sultan Qaboos University | Khor G.L.,International Medical University | Chan Y.M.,University Putra Malaysia | Loke S.C.,University Putra Malaysia | Al-Maskari M.,Sultan Qaboos University
Diabetic Medicine | Year: 2012

Aims In this randomized controlled trial we evaluated the effectiveness of medical nutritional therapy on Arab patients with Type 2 diabetes in Oman delivered by a dietitian. Methods Patients with Type 2 diabetes (n=170) were randomly assigned to a group receiving usual nutritional care (n=85) or a group receiving practice guidelines nutritional care (n=85). Anthropometric (weight, height, BMI and waist circumference) and biochemical (fasting blood glucose, HbA 1c) variables were measured at baseline and after each appointment. Patients were given 1-3 appointments with a dietitian over 6months. Results Those in the group receiving practice guidelines nutritional care (n=85) had significant changes in HbA 1c (-0.8%, P=0.001), fasting plasma glucose (-1.3mmol\l, P=0.003) and weight (-5.1kg, P=0.05), whereas the patients in the usual nutritional care group (n=85) had no significant improvements in either HbA 1c (-0.4%, P=0.248) or fasting plasma glucose (-0.2mmol/l, P=0.638) during the same period. We also found a significant difference between the group receiving practice guidelines nutritional care and the usual nutritional care group, respectively, in waist circumference (96.9±7.9 vs. 100.0±8.7cm, P=0.019), triglycerides levels (1.42±0.58 vs. 1.98±0.96mmol\l, P=0.001), cholesterol levels (5.1±1.0 vs. 5.5±0.9mmol/l, P=0.009) and LDL cholesterol levels (3.58±0.98 vs. 3.89±0.98mmol/l, P=0.046). Conclusions Medical nutrition therapy provided by dietitians to Arab patients with Type 2 diabetes in Oman resulted in significant improvements in anthropometric and biochemical outcomes in both the usual nutritional care group and the group receiving practice guidelines nutritional care. Subjects with Type 2 diabetes tended to do better with practice guidelines nutritional care than with usual nutritional care. Ongoing medical counselling in nutrition by a trained dietitian is important for better long-term metabolic control. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

Djojodihardjo H.,University Putra Malaysia | Djojodihardjo H.,Al - Azhar University of Indonesia
Acta Astronautica | Year: 2015

The application of BE-FE acoustic-structure interaction on a structure subject to acoustic load is elaborated using the boundary element-finite element acoustic structural coupling and the utilization of the computational scheme developed earlier. The plausibility of the numerical treatment is investigated and validated through application to generic cases. The analysis carried out in the work is intended to serve as a baseline in the analysis of acoustic structure interaction for lightweight structures. Results obtained thus far exhibit the robustness of the method developed. © 2014 IAA. Published by Elsevier Ltd. All rights reserved.

Ratnasingam J.,University Putra Malaysia | Ioras F.,University of New England at Biddeford | Abrudan I.V.,Transilvania University of Brasov
Safety Science | Year: 2012

Studies on the rate of occupational accidents among workers in the wooden furniture industry is sparse, although the industry is deemed to be highly accident prone. Therefore, the rate of occupational accidents among workers in the wooden furniture industry in Malaysia, Thailand, Indonesia and Vietnam were studied, in 240 furniture manufacturing factories, using a structured questionnaire. The findings of the study suggest that contract workers are less prone to occupational accidents compared to their permanent counterparts, and hence, are more productive. Further, the results also revealed that the contract workers have a more positive attitude towards the work, and hence, pick up the essentials of safe working practices quickly. It must therefore be recognized that the "production oriented mentality" prevalent in the wooden furniture industry, which has been argued to compromise occupational safety and health standards in the industry may be debatable. In this context, it is essential for the policy makers to re-examine the employment of contract workers for the furniture manufacturing industry, as changing the psycho-economic parameters of the industry may be warranted before the industry is deemed attractive to a permanent workforce. © 2011 Elsevier Ltd.

Ching S.M.,University Putra Malaysia | Zakaria Z.A.,University Putra Malaysia | Paimin F.,Family medicine specialist
BMC Complementary and Alternative Medicine | Year: 2013

Background: Limited study on the use of complementary alternative medicine (CAM) among patients with diabetes mellitus (DM), particularly in primary -care settings. This study seeks to understand the prevalence, types, expenditures, attitudes, beliefs, and perceptions of CAM use among patients with DM visiting outpatient primary care clinics.Methods: This is a descriptive, cross-sectional study of 240 diabetic patients. CAM is defined as a group of diverse medical and healthcare systems, practices, and products that are not generally considered part of conventional Western medicine. Data analysis was done using SPSS v. 19 and multiple logistic regressions were used to identify predictors of CAM use.Results: The prevalence of CAM use was 62.5 percent. Female were 1.8 times more likely than male in using CAM. Malays (75%) were the most frequent users, followed Indians (18%) and Chinese (6%). Biological therapy (50.0%) were the most widely used, followed by manipulative-body based systems (9.2%), energy system (8.8%), alternative medicine systems (4.6%) and mind-body system (1.7%). In biological therapy, a total of 30.4 percent, 24.2 percent, 13.3 percent, and 7.9 percent of diabetic patients consumed bitter gourd (Momordica Charantia), followed by Misai Kucing (Orthosiphon Stamineus Benth), garlic (Allium Sativum), and Sabah snake grass (Clinacanthus Nutans Lindau) respectively. The mean of the expenditure on CAM usage was RM 52.8 ± 101.9 (US $16.9 ± 32.5) per month. According to multiple logistic regression analyses, being Muslim (OR 5.258, 95 percent CI 2.952-9.368) had significant positive association with CAM use.Conclusions: The prevalence of CAM use was high among diabetics. Islam faith is predictor for CAM use among Type 2 DM patients. The most-common herbs used were bitter gourd (Momordica Charantia) and Misai Kucing (Orthosiphon Stamineus, Benth). Further studies on the anti-glycemic activity of the isolated compound may be needed in the future. © 2013 Ching et al.; licensee BioMed Central Ltd.

Lai K.S.,Agro Biotechnology Institute Malaysia | Yusoff K.,University Putra Malaysia
Plant Cell, Tissue and Organ Culture | Year: 2013

Scanning DNA sequences for polymorphisms and mutations often involve the mismatch specific cleavage by endonucleases at the mismatch sites and subsequent analysis of the digested product for mutation discovery. One of the limitations of using enzymatic mutation detection methods are the cost and availability of a mismatch specific endonuclease. We report the establishment of Nicotiana tabacum L. Cv. Bright Yellow 2 cells stably expressing the truncated ENDO1 (tENDO1) mismatch specific endonuclease. The 5′-Untranslated region of N. tabacum alcohol dehydrogenase gene (NtADH 5′-UTR) under the control of cauliflower mosaic virus (CaMV 35S) promoter was employed to improve the tENDO1 protein yield. To ease the purification process, tENDO1 was secreted into the culture medium and isolated using nickel affinity chromatography. The tENDO1 was estimated to be stably produced in an average of 0.7-0.9 % total soluble protein. Functional test on tENDO1 for mismatch detection demonstrated that tENDO1 retained mismatch specific endonuclease activity resembles its native protein. Further biochemical analysis showed that tENDO1 exhibited mismatch detection specificity and efficiency comparable to other commonly used endonucleases. © 2013 Springer Science+Business Media Dordrecht.

Nur-Nazifah M.,University Putra Malaysia | Sabri M.Y.,University Putra Malaysia | Siti-Zahrah A.,National Fish Health Research Center sH
Fish and Shellfish Immunology | Year: 2014

This study was carried out to determine the antibody responses and protective capacity of an inactivated recombinant vaccine expressing the cell wall surface anchor family protein of Streptococcus agalactiae following oral vaccination against streptococcosis in tilapia. Tilapia were vaccinated orally with 106CFU/mL of the recombinant vaccine incorporated in feed (feed-based recombinant vaccine) (vaccinated group or Group 1), 106CFU/mL of pET-32 Ek/LIC vector without cell wall surface anchor family protein (control group or Group 2), 106CFU/mL of formalin-killed cells of S.agalactiae vaccine incorporated in feed was also prepared (feed-based vaccine) (vaccinated group or Group 3), and unvaccinated control group or Group 4 (fed with commercial pellets). During the course of study, serum, mucus and gut lavage fluid were collected to evaluate the antibody levels via enzyme-linked immunosorbent assay (ELISA). The results showed that tilapia immunized with the feed-based recombinant vaccine developed a strong and significantly (P<0.05) higher IgM antibody response in serum, mucus and gut lavage fluid samples compared to groups 2, 3 and 4. Following heat intervenes and intraperitoneal challenge, the rate of survivors (RPS) was 70% for the vaccinated group, and 0% for the rest of the groups. Therefore, the study revealed that the feed-based recombinant vaccine significantly provides high protection against high dose challenge in heat stress environment and enhances the production of the mucosal and humoral immunity. © 2014 Elsevier Ltd.

Ferdousi Begum M.,University of Rajshahi | Alimon A.R.,University Putra Malaysia
Electronic Journal of Biotechnology | Year: 2011

The recent interest in bioconversion of agricultural and industrial wastes to chemical feedstock has led to extensive studies on cellulolytic enzymes produced by microorganisms. In the present study three lignocellulosic substrates viz. sugarcane bagasse, sawdust and water hyacinth were pre-treated with alkali and enzyme and their effect on bioconversion has been investigated. The ability of selected substrates for induction of cellulase enzyme by A. oryzae ITCC 4857.01 and for the potentiality of the induced enzyme to saccharify the substrates were also assessed. The maximum degree of conversion of substrate (0.415%) and improved specific substrate consumption (0.99 g substrate/g dry biomass) was exhibited in sugarcane bagasse after alkali treatment at 96 hrs. Both alkali-treatment and enzyme-treatment, water hyacinth was the best for cellulase induction and showed maximum endoglucanase activity of 11.42 U/ml. Reducing sugar yield ranged from 1.12 mg/ml for enzyme treated sawdust at 48 hrs to 7.53 mg/ml for alkali treated sugarcane bagasse at 96 hrs. Alkali- treated sugarcane bagasse gave the highest saccharification rate of 9.03% after 96 hrs. The most resistant substrate was sawdust which produced 5.92% saccharification by alkaline treatment. The saccharification of lignocellulosic substrates by enzyme produced by A. oryzae ITCC 4857.01 indicates the enzymes specificity towards the substrates. The use of such enzyme in lingo-cellulose hydrolysis will lead to efficient conversion of cellulose materials to other important products. © 2011 by Pontificia Universidad Católica de Valparaíso, Chile.

Buru A.S.,International Medical University | Pichika M.R.,International Medical University | Neela V.,University Putra Malaysia | Mohandas K.,International Medical University
Journal of Ethnopharmacology | Year: 2014

Ethnopharmacological relevance Cinnamomum species have been widely used in many traditional systems of medicine around the world. In the Malaysian traditional system of medicine, the leaves, stem bark and stem wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum have been used to treat wound infections. To study the antibacterial effects of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum against common bacteria found in wound infections with primary focus on methicillin-resistant Staphylococcus aureus (MRSA). Materials and methods The crude extracts from the leaves, stem-bark and stem-wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum were obtained using sequential extraction with hexane, ethylacetate, methanol and water. The volatile oils were obtained by hydro-distillation. The antibacterial activities of extracts were investigated using disk diffusion assays and broth microdilution assays. Results The volatile oils obtained from the stem-bark of Cinnamomum altissimum, Cinnamomum porrectum and Cinnamomum impressicostatum have shown significant antibacterial activity against a wide range of Gram positive and Gram negative bacteria including MRSA. A few test extracts have shown better activity against MRSA as compared to methicillin sensitive Staphylococcus aureus (MSSA). Amongst all the test extracts, Cinnamomum impressicostatum stem-bark water extract produced the largest inhibition zone of 21.0 mm against MRSA while its inhibition zone against MSSA was only 8.5 mm. The minimum inhibitory concentration (MIC) of this extract against MRSA was 19.5 μg mL-1 and the corresponding minimum bactericidal concentration (MBC) was 39.0 μg mL-1. Conclusions This study has scientifically validated the traditional use of Cinnamomum species in treating wound infections. Of high scientific interest was the observation that the antibacterial effect of Cinnamomum impressicostatum stem-bark crude water extract against MRSA was significantly higher than its effect against MSSA, suggesting that the extract contains a compound(s) with higher specific neutralising activity against the drug resistance markers of MRSA. © 2014 Elsevier Ireland Ltd.

Hossain M.M.,University Putra Malaysia | Mani K.K.C.,University Putra Malaysia | Islam M.R.,University of Rajshahi
PLoS Neglected Tropical Diseases | Year: 2015

The number of child deaths is a potential indicator to assess the health condition of a country, and represents a major health challenge in Bangladesh. Although the country has performed exceptionally well in decreasing the mortality rate among children under five over the last few decades, mortality still remains relatively high. The main objective of this study is to identify the prevalence and determinants of the risk factors of child mortality in Bangladesh. The data were based on a cross-sectional study collected from the Bangladesh Demographic and Health Survey (BDHS), 2011. The women participants numbered 16,025 from seven divisions of Bangladesh – Rajshahi, Dhaka, Chittagong, Barisal, Khulna, Rangpur and Sylhet. The χ2 test and logistic regression model were applied to determine the prevalence and factors associated with child deaths in Bangladesh. In 2011, the prevalence of child deaths in Bangladesh for boys and girls was 13.0% and 11.6%, respectively. The results showed that birth interval and birth order were the most important factors associated with child death risks; mothers’ education and socioeconomic status were also significant (males and females). The results also indicated that a higher birth order (7 & more) of child (OR=21.421 & 95%CI=16.879-27.186) with a short birth interval ≤ 2 years was more risky for child mortality, and lower birth order with longer birth interval >2 were significantly associated with child deaths. Other risk factors that affected child deaths in Bangladesh included young mothers of less than 25 years (mothers’ median age (26-36 years): OR=0.670, 95%CI=0.551-0.815), women without education compared to those with secondary and higher education (OR =0 .711 & .628, 95%CI=0.606-0.833 & 0.437-0.903), mothers who perceived their child body size to be larger than average and small size (OR= 1.525 & 1.068, 95%CI=1.221-1.905 & 0.913-1.249), and mothers who delivered their child by non-caesarean (OR= 1.687, 95%CI=1.253-2.272). Community-based educational programs or awareness programs are required to reduce the child death in Bangladesh, especially for younger women should be increase the birth interval and decrease the birth order. The government should apply the strategies to enhance the socioeconomic conditions, especially in rural areas, increase the awareness program through media and expand schooling, particularly for girls. © 2015 Hossain et al.

Kumar R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia | Rashid S.A.,University Putra Malaysia | Matsuura T.,University of Ottawa
RSC Advances | Year: 2013

Biocompatible and naturally occurring chitosan was used as an additive for the preparation of a polysulfone ultrafiltration membrane. Two different compositions of polysulfone in N-methylpyrrolidone (NMP) and chitosan in 1% acetic acid were blended to prepare PSf-CS ultrafiltration membranes by the diffusion induced phase separation (DIPS) method. The proper blending of polysulfone and chitosan in PSf-CS membranes was confirmed by ATR-IR analysis. The surface and cross-sectional morphology of the membranes was studied by scanning electron microscopy (SEM). The membrane hydrophilicity was determined by water uptake and contact angle measurements. The PSf-CS membrane showed an enhanced hydrophilicity compared to a PSf ultrafiltration membrane. The time dependent permeation studies revealed the improved flux of PSf-CS membranes. PSf-CS membranes were subjected to bovine serum albumin (BSA) protein rejection studies. An improved antifouling property was observed for PSf-CS blend membranes as compared to pristine PSf ultrafiltration membranes. Both the permeation and antifouling properties of PSf-CS membranes increased with an increase in chitosan composition. © 2013 The Royal Society of Chemistry.

Hasan A.,University of Malaya | Abbas A.,Quaid-i-Azam University | Akhtar M.N.,University Putra Malaysia
Molecules | Year: 2011

A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature. © 2011 by The Authors.

Jahedsaravani A.,University Putra Malaysia | Marhaban M.H.,University Putra Malaysia | Massinaei M.,Birjand University
Minerals Engineering | Year: 2014

It is now generally accepted that froth appearance is a good indicative of the flotation performance. In this paper, the relationship between the process conditions and the froth features as well as the process performance in the batch flotation of a copper sulfide ore is discussed and modeled. Flotation experiments were conducted at a wide range of operating conditions (i.e. gas flow rate, slurry solids%, frother/collector dosage and pH) and the froth features (i.e. bubble size, froth velocity, froth color and froth stability) along with the metallurgical performances (i.e. copper/mass/water recoveries and concentrate grade) were determined for each run. The relationships between the froth characteristics and performance parameters were successfully modeled using the neural networks. The performance of the developed models was evaluated by the correlation coefficient (R) and the root mean square error (RMSE). The results indicated that the copper recovery (RMSE = 2.9; R = 0.9), concentrate grade (RMSE = 1.07; R = 0.92), mass recovery (RMSE = 1.94; R = 0.94) and water recovery (RMSE = 3.07; R = 0.95) can be accurately predicted from the extracted surface froth features, which is of central importance for control purposes. © 2014 The Authors. Published by Elsevier Ltd.

Abbasalipourkabir R.,Hamadan University of Medical Sciences | Salehzadeh A.,Hamadan University of Medical Sciences | Abdullah R.,University Putra Malaysia
Biotechnology | Year: 2011

Recently more focus has been put to the development of innovative drug-delivery systems that includes liposomes and solid lipid nanoparticles (SLNs). An in vitro study was conducted to determine the effect of solid lipid nanoparticle on the human breast cancer cell lines (MCF-7 and MDA-MB231). The SLNs based on palm oil were prepared using the high pressure homogenization method and were characterized by the particle size and polydispersity index (particle sizer), zeta potential (zetasizer), ultrastructure [transmission electron microscopy (TEM)] and MTT assay and natural red assay. Homogenization of solid lipid nanoparticles at 1000 bar for 20 cycles produced particles with 145.00±3.39 nm in size and zeta potential of-19.50±l .80 mv. The SLNs were generally round and uniform in shape. The cytotoxicity of the components of the SLN formulation was low: SLN with 1 % oleyl alcohol displayed no significant cytotoxicity effect on breast cancer cells. In the light of these findings, SLN stabilized with 30% lecithin and 1% oleyl alcohol as nonionic co-surfactant in aqueous phase was found to be safe for cells and the acceptable for the incorporation hpophihc drugs. © 2011 Asian Network for Scientific Information.

Esfandiari E.,Islamic Azad University at Majlesi | Mariun N.B.,University Putra Malaysia
IEEE Transactions on Industrial Electronics | Year: 2013

This paper provides experimental results for a 2.5-kW 47-level prototype of the switch-ladder multilevel inverter including the following: input and output voltage and current waveforms under resistive and inductive loads, efficiency, total harmonic distortion, voltage stresses across the switches, behavior of the system under fault condition, and no-load power dissipation. The most important advantage of this inverter is that only four switches conduct in each interval in low frequency. This matter, beside the elimination of switching losses, has made this inverter an efficient choice with 97% peak efficiency. The ability to continue working with open-circuit modules is another advantage of the inverter. Furthermore, some important factors behind the unreliability and inefficiency of inverters have been improved, including the following: low duty cycle of conducting switches, staircase voltage stresses across switches with low-voltage steppes, line switching frequency results in low temperature of switches, possibility of removing low-pass filters, and independence to capacitors. The inverter is proposed to be an advantageous choice in low-voltage stand-alone photovoltaic applications. © 1982-2012 IEEE.

Mondal M.N.I.,University Putra Malaysia | Mondal M.N.I.,University of Rajshahi | Shitan M.,University Putra Malaysia
Journal of Epidemiology | Year: 2014

Background: We attempted to identify the pathways by which demographic changes, socioeconomic inequalities, and availability of health factors influence life expectancy in low- and lower-middle-income countries. Methods: Data for 91 countries were obtained from United Nations agencies. The response variable was life expectancy, and the determinant factors were demographic events (total fertility rate and adolescent fertility rate), socioeconomic status (mean years of schooling and gross national income per capita), and health factors (physician density and human immunodeficiency virus [HIV] prevalence rate). Path analysis was used to determine the direct, indirect, and total effects of these factors on life expectancy. Results: All determinant factors were significantly correlated with life expectancy. Mean years of schooling, total fertility rate, and HIV prevalence rate had significant direct and indirect effects on life expectancy. The total effect of higher physician density was to increase life expectancy. Conclusions: We identified several direct and indirect pathways that predict life expectancy. The findings suggest that policies should concentrate on improving reproductive decisions, increasing education, and reducing HIV transmission. In addition, special attention should be paid to the emerging need to increase life expectancy by increasing physician density. © 2013 Md. Nazrul Islam Mondal et al.

Shakerardekani A.,Iranian Pistachio Research Institute | Karim R.,University Putra Malaysia | Ghazali H.M.,University Putra Malaysia | Chin N.L.,University Putra Malaysia
International Journal of Molecular Sciences | Year: 2013

Tree nuts are rich in macro and micronutrients, phytochemicals, tocopherols and phenolic compounds. The development of nut spreads would potentially increase the food uses of nuts and introduce consumers with a healthier, non-animal breakfast snack food. Nut spreads are spreadable products made from nuts that are ground into paste. Roasting and milling (particle size reduction) are two important stages for the production of nut spreads that affected the textural, rheological characteristic and overall quality of the nut spread. Textural, color, and flavor properties of nut spreads play a major role in consumer appeal, buying decisions and eventual consumption. Stability of nut spreads is influenced by its particle size. Proper combination of ingredients (nut paste, sweetener, vegetable oil and protein sources) is also required to ensure a stable nut spread product is produced. Most of the nut spreads behaved like a non-Newtonian pseudo-plastic fluid under yield stress which help the producers how to start pumping and stirring of the nut spreads. Similar to other high oil content products, nut spreads are susceptible to autoxidation. Their oxidation can be controlled by application of antioxidants, using processing techniques that minimize tocopherol and other natural antioxidant losses. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Vigneault A.,University of British Columbia | Elnashaie S.S.E.H.,University Putra Malaysia | Grace J.R.,University of British Columbia
Chemical Engineering and Technology | Year: 2012

A steady-state 2D model is developed for a multichannel membrane reactor (MCMR) to produce pure hydrogen. The model includes one reforming channel coupled with a PdAg membrane to produce H2 and one combustion channel to generate the heat needed for the reforming. Both isothermal and non-isothermal simulations are applied in designing a laboratory-scale proof-of-concept reactor. Isothermal sensitivity analysis indicates parameter adjustments practically available to improve reactor performance. In non-isothermal simulations, catalyst layer thickness and kinetic pre-exponential factor are varied along the reactor length. Predictions indicate that the reforming methane conversion increased from 74% to 91%, while avoiding hot spots. Compared with other membrane reactors, the MCMR has the potential for one to two orders of magnitude higher H2 production per reactor volume and per mass of catalyst. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yuliana N.D.,Leiden University | Yuliana N.D.,Bogor Agricultural University | Khatib A.,University Putra Malaysia | Verpoorte R.,Leiden University | Choi Y.H.,Leiden University
Analytical Chemistry | Year: 2011

A large number of plant metabolites has provided as an incomparable chemical source for drug development. However, the wide range of the polarity of metabolites has been a big obstacle for full use of the chemical diversity. The initial step conventional extraction method by a single solvent does not make use of all the metabolites contained in plants. Also, it takes a long time to confirm the target activity of a single compound because of tedious separation steps. To solve the problem, a new extraction method coupled to NMR-based metabolomics is applied to identify bioactive natural products. A comprehensive extraction method consisting of a continuous flow of solvent mixtures through plant material was developed to provide extracts with a wider chemical variety than those yielded with a single solvent extraction. As the model experiment, 1H NMR spectra of the extracts obtained from the comprehensive extraction of Orthosiphon stamineus were subjected to multivariate data analysis to find its adenosine A1 binding activity. On the basis of the results, two flavonoids from a large number of chemicals were clearly verified to show the adenosine A1 binding activity without any further purification steps. This method could provide a solution to the major drawbacks of natural products in drug development. © 2011 American Chemical Society.

Mondal M.N.I.,University Putra Malaysia | Mondal M.N.I.,University of Rajshahi | Shitan M.,University Putra Malaysia
African Health Sciences | Year: 2013

Background: All over the world the prevalence of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) has became a stumbling stone in progress of human civilization and is a huge concern for people worldwide. Objective: To determine the social and health factors which contribute to increase the size of HIV epidemic globally. Methods: The country level indicators of HIV prevalence rates, are contraceptive prevalence rate, physicians density, proportion of Muslim populations, adolescent fertility rate, and mean year of schooling were compiled of 187 countries from the United Nations (UN) agencies. To extract the major factors from those indicators of the later five categories, backward multiple regression analysis was used as the statistical tool. Results: The national HIV prevalence rate was significantly correlated with almost all the predictors. Backward multiple linear regression analysis identified the proportion of Muslims, physicians density, and adolescent fertility rate are as the three most prominent factors linked with the national HIV epidemic. Conclusions: The findings support the hypotheses that a higher adolescent fertility rate in the population is the adverse effect of premarital and extramarital sex that leads to longer period of sexual activity which increases the risk of HIV infection. On the hand, and cultural restrictions of Muslims and sufficient physicians will decelerate the spread of HIV infections in the society.

Rahimian F.P.,University of Central Lancashire | Ibrahim R.,University Putra Malaysia
Design Studies | Year: 2011

Conventional Computer Aided Design tools lack intuitivity for being used in conceptual architectural design process. This paper identifies the impact of using a haptic based VR 3D sketching interface for integrating novice designers' cognitions and actions to improve design creativity. This study employs protocol analysis for comparing the collective cognitive and collaborative design protocols of three pairs of novice architectural designers in both 3D and manual sketching sessions. Results show that the simple and tangible haptic based design interface improved designers' cognitive and collaborative activities. These improvements also increased their engagement with 'problem-space' and 'solution-space' that led towards more artefact maturity. Research findings from this study can help the development of cutting-edge haptic-based collaborative virtual environments in architectural education and associated professions. © 2010 Elsevier Ltd. All rights reserved.

Ramli Z.,Malaysian Palm Oil Board | Abdullah S.N.A.,University Putra Malaysia
Plant Molecular Biology Reporter | Year: 2010

In silico analysis showed that the differentially expressed type 3 oil palm metallothionein-like genes MT3-A and MT3-B share at least 11 common putative promoter regulatory elements. The identified motifs include W-boxes, TATCCA element, binding element for cytokinin response regulators and pollen-specific elements. A high degree of conservation was observed in their genomic organisation where the coding regions are divided at two identical positions in both genes by two AT-rich introns. Promoter activity of the MT3-B gene was analysed using a transient assay by bombarding oil palm tissue slices with a β-glucuronidase (GUS) gene construct and a stable reporter assay by analysing GUS expression in transformed Arabidopsis thaliana plants. Transient expression analysis revealed MT3-B promoter activity in oil palm root tissues but not in fruit mesocarp at 12 weeks after anthesis and spear leaves. The T3 homozygous transgenic Arabidopsis plants, harbouring the MT3-B promoter/GUS construct, showed reporter activity in cotyledons and mature leaves with lower expression levels in root tissues. The expression levels in the roots of the T3 homozygous transgenic plants increased five- and 2. 5-folds when treated with 80 μM of Zn2+ and Fe2+, respectively. Altogether, these results indicate that the MT3-A and MT3-B promoter activities may be regulated by a variety of abiotic factors and MT3-B promoter may potentially be manipulated for use in plant genetic engineering for induced synthesis of gene product. © Springer-Verlag 2010.

Saadi S.,University Putra Malaysia | Saari N.,University Putra Malaysia | Anwar F.,University of Sargodha | Anwar F.,Salman bin Abdulaziz University | And 2 more authors.
Biotechnology Advances | Year: 2015

The growing momentum of several common life-style diseases such as myocardial infarction, cardiovascular disorders, stroke, hypertension, diabetes, and atherosclerosis has become a serious global concern. Recent developments in the field of proteomics offering promising solutions to solving such health problems stimulates the uses of biopeptides as one of the therapeutic agents to alleviate disease-related risk factors. Functional peptides are typically produced from protein via enzymatic hydrolysis under in vitro or in vivo conditions using different kinds of proteolytic enzymes. An array of biological activities, including antioxidative, antihypertensive, antidiabetic and immunomodulating has been ascribed to different types of biopeptides derived from various food sources. In fact, biopeptides are nutritionally and functionally important for regulating some physiological functions in the body; however, these are yet to be extensively addressed with regard to their production through advance strategies, mechanisms of action and multiple biological functionalities. This review mainly focuses on recent biotechnological advances that are being made in the field of production in addition to covering the mode of action and biological activities, medicinal health functions and therapeutic applications of biopeptides. State-of-the-art strategies that can ameliorate the efficacy, bioavailability, and functionality of biopeptides along with their future prospects are likewise discussed. © 2015 Elsevier Inc.

Anarjan N.,Islamic Azad University at Tabriz | Tan C.P.,University Putra Malaysia
Food Chemistry | Year: 2013

Solubilising astaxanthin in nanodispersion systems is a promising approach to incorporate astaxanthin into water-based food formulations. In this research, the chemical stabilities of astaxanthin nanodispersions diluted in orange juice and skimmed milk as model food systems and in deionised water as a control were evaluated. The nanodispersions displayed significantly (p < 0.05) better stability in food systems compared to the control. The effects of stabilisers and dilution factor were also studied. In skimmed milk and deionised water, the type of stabiliser had a significant effect (p < 0.05) on astaxanthin degradation during storage. In vitro cellular uptake of astaxanthin from diluted astaxanthin nanodispersions in selected food systems was also evaluated. The cellular uptake of astaxanthin nanodispersions in skimmed milk was significantly higher (p < 0.05) than that of astaxanthin nanodispersions in orange juice and deionised water. High in vitro cellular uptake of astaxanthin from the prepared astaxanthin nanodispersions can be achieved via incorporation into protein-based foods such as milk. © 2013 Elsevier Ltd. All rights reserved.

Ali F.,University Putra Malaysia | Ismail A.,University Putra Malaysia | Kersten S.,Wageningen University
Molecular Nutrition and Food Research | Year: 2014

Obesity and related metabolic diseases (e.g., type 2 diabetes, cardiovascular diseases, and hypertension) are the most prevailing nutrition-related issues in the world. An emerging feature of obesity is their relationship with chronic inflammation that begins in white adipose tissue and eventually becomes systemic. One potential dietary strategy to reduce glucose intolerance and inflammation is consumption of polyphenol-rich cocoa-like cocoa or their by-products. In vitro as well as in vivo data indicate that cocoa polyphenols (CPs) may exhibit antioxidant and anti-inflammatory properties. Polyphenols commonly found in cocoa have been reported to regulate lipid metabolism via inducing metabolic gene expression or activating transcription factors that regulate the expression of numerous genes, many of which play an important role in energy metabolism. Currently, several molecular targets (e.g., nuclear factor Kappa B, activated protein-1, peroxisome proliferator-activated receptors, liver X receptors, and adiponectin gene) have been identified, which may explain potential beneficial obesity-associated diseases effects of CPs. Further studies have been performed regarding the protective effects of CPs against metabolic diseases by suppressing transcription factors that antagonize lipid accumulation. Thus, polyphenols-rich cocoa products may diminish obesity-mediated metabolic diseases by multiple mechanisms, thereby attenuating chronic inflammation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Subramani T.,University Putra Malaysia | Rathnavelu V.,Sri Ramachandra University | Alitheen N.B.,University Putra Malaysia
Mediators of Inflammation | Year: 2013

Gingival overgrowth is a side effect of certain medications. The most fibrotic drug-induced lesions develop in response to therapy with phenytoin, the least fibrotic lesions are caused by cyclosporin A, and the intermediate fibrosis occurs in nifedipine-induced gingival overgrowth. Fibrosis is one of the largest groups of diseases for which there is no therapy but is believed to occur because of a persistent tissue repair program. During connective tissue repair, activated gingival fibroblasts synthesize and remodel newly created extracellular matrix. Proteins such as transforming growth factor (TGF), endothelin-1 (ET-1), angiotensin II (Ang II), connective tissue growth factor (CCN2/CTGF), insulin-like growth factor (IGF), and platelet-derived growth factor (PDGF) appear to act in a network that contributes to the development of gingival fibrosis. Since inflammation is the prerequisite for gingival overgrowth, mast cells and its protease enzymes also play a vital role in the pathogenesis of gingival fibrosis. Drugs targeting these proteins are currently under consideration as antifibrotic treatments. This review summarizes recent observations concerning the contribution of TGF-β, CTGF, IGF, PDGF, ET-1, Ang II, and mast cell chymase and tryptase enzymes to fibroblast activation in gingival fibrosis and the potential utility of agents blocking these proteins in affecting the outcome of drug-induced gingival overgrowth. © 2013 Tamilselvan Subramani et al.

Modarres Khiyabani F.,Islamic Azad University at Tabriz | Leong W.J.,University Putra Malaysia
Computers and Mathematics with Applications | Year: 2012

Quasi-Newton (QN) methods are generally held to be the most efficient minimization methods for solving unconstrained optimization problems. Among the QN methods, symmetric rank-one (SR1) is one of the very competitive formulas. In the present paper, we propose a new SR1 method. The new technique attempts to improve the quality of the SR1 Hessian by employing the scaling of the identity in a certain sense. However, since at some iterations these updates might be singular, indefinite or undefined, this paper proposes an updates criterion based on the eigenvalues of the SR1 update to measure this quality. Hence, the new method is employed only to improve the approximation of the SR1 Hessian. It is shown that the numerical results support the theoretical considerations for the usefulness of this criterion and show that the proposed method improves the performance of the SR1 update substantially. © 2012 Elsevier Ltd. All rights reserved.

Yu Q.,University of Western Australia | Ahmad-Hamdani M.S.,University of Western Australia | Ahmad-Hamdani M.S.,University Putra Malaysia | Han H.,University of Western Australia | And 2 more authors.
Heredity | Year: 2013

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. © 2013 Macmillan Publishers Limited All rights reserved.

Hazir M.H.M.,University Putra Malaysia | Shariff A.R.M.,University Putra Malaysia | Amiruddin M.D.,Malaysian Palm Oil Board
Industrial Crops and Products | Year: 2012

Non-destructive and real-time oil palm fresh fruit bunch (FFB) grading systems are of major exploratory concern for researchers in the oil palm industry. The objective is to reduce time, labour, costs, and most importantly, to increase the oil extraction rate, in order to achieve a good quality of palm oil at a more acceptable price. This research investigates the potential of flavonoids and anthocyanins as a predictor to classify the degree of oil palm FFB ripeness. This paper also discusses the relationship between these predictors and the ripeness categories period. One hundred and eighty oil palm FFB samples were collected from a private plantation in Malaysia, according to three maturity categories i.e., ripe, under-ripe, and over-ripe. Each sample was randomly scanned 10 times, both front and back using a hand-held Multiplex ®3 multi-parameter fluorescence sensor. The results show that flavonoid and anthocyanin content decreased from immature to over mature oil palm FFBs. Overall, the relationship using Pearson's correlation between flavonoids and anthocyanins was r 2=0.84 and the most outstanding relationship accuracy was at the over-ripe stage, at 90%. Statistical analysis using analysis of variance (ANOVA) and pair-wise testing proved that both predictors gave significance difference between under-ripe, ripe, and over-ripe maturity categories. This shows that both predictors can be good indicators to classify oil palm FFB. Classification analysis was performed by using both predictors together and separately through several methods. The highest overall classification accuracy was 87.7% using a Stochastic Gradient Boosting Trees model and with both predictors. The other classification methods used either independent or both predictors together and gave various results ranging from 50 to 85% accuracy. This research proves that flavonoids and anthocyanins can be used as predictors of oil palm maturity classification. © 2011 Elsevier B.V.

Azizi S.,University Putra Malaysia | Ahmad M.B.,University Putra Malaysia | Namvar F.,University Putra Malaysia | Namvar F.,Islamic Azad University at Mashhad | Mohamad R.,University Putra Malaysia
Materials Letters | Year: 2014

Biosynthesis of nanoparticles is an important area in the field of nanotechnology which has economic and eco-friendly benefits over chemical and physical methods of synthesis. The present contribution deals with one pot method for synthesis of zinc oxide nanoparticles (ZnO NPs) through green process using the brown marine macroalgae Sargassum muticum (S.muticum) aqueous extract. FTIR spectra revealed the involvement of sulfate and hydroxyl moieties of polysaccharide in the formation of ZnO NPs. Pure ZnO NPs were obtained after calcination of S.muticum formed ZnO at 450 C. FESEM analysis shows that the pure ZnO NPs synthesized have hexagonal wurtzite structures and the average size ranged from 30 to 57 nm. The UV-vis absorption spectra of the pure ZnO NPs exhibited absorption peaks in the UV region which were attributed to the band gap of the ZnO NPs. © 2013 Elsevier B.V.

Yida Z.,University Putra Malaysia | Yida Z.,Chengde Medical University | Imam M.U.,Chengde Medical University | Ismail M.,University Putra Malaysia
BMC Complementary and Alternative Medicine | Year: 2014

Background: Edible birds' nest (EBN) is reported to be antioxidant-rich. However, the fate of its antioxidants after oral consumption is not yet reported. To explore this, we hypothesized that EBN antioxidants are released from their matrix when subjected to in vitro simulated gastrointestinal digestion. Methods: EBN samples were extracted using hot water (100°C) with or without subsequent sequential enzymatic digestion using pepsin (10,000 units), pancreatin (36 mg) and bile extracts (112.5 mg). Additionally, pH changes (8.9 to 2 and back to 8.9) similar to the gut were applied, and a 10 KDa dialysis tubing was used to simulate gut absorption. The antioxidant capacities of the water extracts of EBN before and after digestion were then determined using ABTS and oxygen radical absorbance capacity (ORAC) assays, while the protective effects of the EBN samples against hydrogen peroxide-induced toxicity in HEPG2 cells were determined using MTT assay and acridine orange (AO)/propidium iodide (PI) staining. Results: Antioxidant assays (ABTS and ORAC) showed that the undigested EBN water extract had little antioxidant activity (1 and 1%, respectively at 1000 μg/mL) while at similar concentrations the digested samples had significantly (p < 0.05) enhanced antioxidant activities, for samples inside (38 and 50%, respectively at 1000 μg/mL) and outside (36 and 50%, respectively at 1000 μg/mL) the dialysis tubing, representing absorbed and unabsorbed samples, respectively. Cell viability and toxicity assays also suggested that the EBN extracts were non-toxic to HEPG2 cells (cell viabilities of over 80% at 1000 μg/mL), while AOPI showed that the extracts protected HEPG2 cells from hydrogen peroxide induced-toxicity. Conclusions: Based on the findings, it is likely that EBN bioactives are released from their matrix when digested in the gut and then absorbed through the gut by passive-mediated transport to exert their functional effects. However, there is need to confirm these findings using in vivo systems to determine their clinical significance. © 2014 Yida et al.

Fadaeenejad M.,University Putra Malaysia | Saberian A.M.,University Putra Malaysia | Fadaee M.,Islamic Azad University at Mashhad | Radzi M.A.M.,University Putra Malaysia | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2014

Strong and huge interests on smart grid have increased extensively in recent years around the world. This scenario could be a promising reason for future research in this area. This next form of electricity grid will be able to manage various parts of power production from power plants to the customers. Smart grid has become a major challenge in developed nations in both research and utilization aspects. On the other side, application of smart grid in developing countries is still lagging behind as compared to the developed ones. However, most of developing nations are currently investigating potentials of some pilot projects or few research works. In this article, the applied activities in developing countries for smart grid are reviewed and categorized into two major groups: group of pioneer developing countries in smart grid and other developing countries are placed in another group. The findings demonstrate that a few countries such as China, India and Brazil have had proper planning and development in this technology. In some cases like China, the efforts are considered comparable with developed nations like U.S. Therefore, according to the development progress for smart grid in China, India and Brazil, a pattern of reference for other developing countries is suggested. © 2013 Elsevier Ltd.

Amin M.,University of Sargodha | Anwar F.,University of Sargodha | Janjua M.R.S.A.,University of Sargodha | Iqbal M.A.,University of Sargodha | Rashid U.,University Putra Malaysia
International Journal of Molecular Sciences | Year: 2012

A green synthesis route for the production of silver nanoparticles using methanol extract from Solanum xanthocarpum berry (SXE) is reported in the present investigation. Silver nanoparticles (AgNps), having a surface plasmon resonance (SPR) band centered at 406 nm, were synthesized by reacting SXE (as capping as well as reducing agent) with AgNO 3 during a 25 min process at 45 °C. The synthesized AgNps were characterized using UV-Visible spectrophotometry, powdered X-ray diffraction, and transmission electron microscopy (TEM). The results showed that the time of reaction, temperature and volume ratio of SXE to AgNO 3 could accelerate the reduction rate of Ag + and affect the AgNps size and shape. The nanoparticles were found to be about 10 nm in size, mono-dispersed in nature, and spherical in shape. In vitro anti-Helicobacter pylori activity of synthesized AgNps was tested against 34 clinical isolates and two reference strains of Helicobacter pylori by the agar dilution method and compared with AgNO 3 and four standard drugs, namely amoxicillin (AMX), clarithromycin (CLA), metronidazole (MNZ) and tetracycline (TET), being used in anti-H. pylori therapy. Typical AgNps sample (S1) effectively inhibited the growth of H. pylori, indicating a stronger anti-H. pylori activity than that of AgNO 3 or MNZ, being almost equally potent to TET and less potent than AMX and CLA. AgNps under study were found to be equally efficient against the antibiotic-resistant and antibiotic-susceptible strains of H. pylori. Besides, in the H. pylori urease inhibitory assay, S1 also exhibited a significant inhibition. Lineweaver-Burk plots revealed that the mechanism of inhibition was noncompetitive. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Anarjan N.,Islamic Azad University at Tabriz | Tan C.P.,University Putra Malaysia
JAOCS, Journal of the American Oil Chemists' Society | Year: 2013

Astaxanthin, as a functional lipid, can be incorporated easily into different water-based food formulations in the form of a nanodispersion. In this study, astaxanthin nanodispersions were produced using different stabilizer systems, namely, polysorbate 20 (PS20), sodium caseinate (SC), gum arabic (GA) and an optimum combination of these three stabilizers (OPT). Since astaxanthin is sensitive to oxidative damage, its degradations kinetics in the prepared nanodispersion systems were investigated as a function of storage temperature, atmosphere and light. The results showed that astaxanthin degradation followed a first-order kinetic and, in most cases, astaxanthin was more stable in optimum-formulated three-component-stabilized nanodispersions as compared to nanodispersion systems stabilized by individual stabilizers. In addition, high storage temperature and intense illumination significantly (P < 0.05) increased the degradation of astaxanthin, while oxygen-free conditions significantly (P < 0.05) reduced the astaxanthin degradation rate. © 2013 AOCS.

Anarjan N.,University Putra Malaysia | Anarjan N.,Islamic Azad University at Tabriz | Tan C.P.,University Putra Malaysia
Food Hydrocolloids | Year: 2013

Astaxanthin nanodispersions were prepared using Polysorbate 20 (PS20), sodium caseinate (SC) and gum Arabic (GA), solely or in combinations, as stabilizer system, through a solvent-diffusion process. The interactions among these three surface active compounds, in the formation, physicochemical and stability characterization of produced nanodispersions were studied by applying a simplex centroid mixture design. Quadratic or special cubic regression models were fitted for variations of all studied responses as function of significant (p < 0.05) interaction effects between stabilizer components' proportions, with acceptable determination coefficients (>0.70). Multiple-response optimization predicted that by using 29% (w/w) PS20, 6% (w/w) GA and 65% (w/w) SC as a three component stabilizer system, an astaxanthin nanodispersion could be produced with the most desirable physicochemical characteristics and highest physicochemical stability. At this optimum stabilizer components proportions, the corresponding predicted response values for mean particle size, polydispersity index (PDI) and total astaxanthin loss were predicted to be 114.6 nm, 0.261 and 680 mg/L, respectively. The optimum astaxanthin nanodispersions also showed 2.06% and 1.05% particle size growth at 25 °C and 5 °C, 4.56% and 1.29% PDI growth at 25 °C and 5 °C, and 20% (w/w) astaxanthin loss at 25 °C after 8 weeks of storage. The absence of significant (p > 0.05) differences between the experimental and predicted values of the response variables confirmed the adequacy of the fitted models. © 2012 Elsevier Ltd.

Arafat H.A.,Masdar Institute of Science and Technology | Jijakli K.,Masdar Institute of Science and Technology | Ahsan A.,University Putra Malaysia
Journal of Cleaner Production | Year: 2015

In this study, the environmental impacts were assessed for five municipal solid waste (MSW) treatment processes with energy recovery potential. The life cycle assessment (LCA) tool was used to quantify the environmental impacts. The five processes considered are incineration, gasification, anaerobic digestion, bio-landfills, and composting. In addition, these processes were compared to recycling where applicable. In addition to environmental impacts quantification, the energy production potentials for the five processes were compared to provide a thorough assessment. To maximize the future applicability of our findings, the analyses were based on the waste treatment technologies as they apply to individual waste streams, but not for a specific MSW mixture at a particular location. Six MSW streams were considered; food, yard, plastic, paper, wood and textile wastes. From an energy recovery viewpoint, it was found that it is best to recycle paper, wood and plastics; to anaerobically digest food and yard wastes; and to incinerate textile waste. On the other hand, the level of environmental impact for each process depends on the considered impact category. Generally, anaerobic digestion and gasification were found to perform better environmentally than the other processes, while composting had the least environmental benefit. © 2013 Elsevier Ltd. All rights reserved.

Ng W.L.,Kyushu University | Ng W.L.,University Putra Malaysia | Szmidt A.E.,Kyushu University
Aquatic Botany | Year: 2015

Natural hybridization is common in plants, including mangroves. Three Rhizophora mangrove species are recognized in the Indo-West Pacific region, namely R. apiculata, R. mucronata, and R. stylosa. So far, R. apiculata has been known to form sterile hybrid offspring with R. mucronata (= R. x annamalayana) and with R. stylosa (= R. x lamarckii). A third hybrid between morphologically similar R. mucronata and R. stylosa was only recently shown to exist, via DNA sequencing. However, it has been suspected that this newly discovered hybrid may be fertile, with potential to interbreed to give rise to advanced-generation hybrids in locations where both parental species occur. In this study, inter-simple sequence repeat (ISSR) markers were used to survey several stands where R. mucronata and R. stylosa co-occur. By screening through 26 ISSR primers, a set of species-specific diagnostic bands for each species were first identified from standard samples before being used to genotype the test samples. A chloroplast DNA locus was also sequenced in the test samples to determine the direction of hybridization. Results showed that hybridization occurred between R. mucronata and R. stylosa in all investigated locations with differing levels of introgression, and that it could happen in any direction. © 2014 Elsevier B.V.

Ibrahim R.,University Putra Malaysia | Pour Rahimian F.,University of Central Lancashire
Automation in Construction | Year: 2010

Communications for information synchronisation during the conceptual design phase usually require designers to employ more flexible and intuitive digital design tools. In developing such support tools, a case study research was initiated to first understand the current state of communication among novice design team members. The main purpose of the study is to understand the novice designers' collaboration culture when working on conceptual architectural design projects. The overall case study research involves 1) ethnography for data collection and 2) artefact and protocol analyses for data analysis. This paper presents the latter data analyses based on the earlier ethnography results about novice designers' conceptual design and technology design synthesis strategies. Data analyses on the characteristics of utilised external representation tools indicate that although conventional manual sketching is beneficial for providing rich intuitive design concepts, they have limitations when novice designers need to oversee complicated design problems. The study also found that although current conventional CAD tools are advantageous for detailed engineering design articulation, they do hinder novice designers' creativity due to their intuitive ideation limitation. Based on these results, this paper discusses the identified advantages and challenges of current design media and then proposes an alternative VR-based design interface for enhancing cognition and communication among designers during the conceptual design phase. © 2010 Elsevier B.V. All rights reserved.

Varahram P.,University Putra Malaysia | Al-Azzo W.F.,Dhofar University | Ali B.M.,University Putra Malaysia
IEEE Transactions on Consumer Electronics | Year: 2010

In this paper a novel technique for reducing the peak to average power ratio (PAPR) in OFDM systems by using the combination of the dummy sequence insertion (DSI) and partial transmit sequence (PTS) is proposed. In DSI increasing the number of dummy sequence decrease the transmission efficiency (TE) and in PTS the complexity increases when the number of subblock increases. Unlike the conventional PTS which needs several inverse fast fourier transform (IFFT) operations, the proposed DSI-PTS technique requires half IFFT operations only, while the PAPR performance is even better. So, it can remarkably reduce the computational complexity. Simulation results are examined with IEEE 802.16-2004 standard. By applying the DSI-PTS method about 0.5 dB reduction in PAPR at complementary cumulative distribution function (CCDF) of 0.01% is achieved compared to the conventional PTS while the complexity is reduced. © 2006 IEEE.

Saberi A.H.,University Putra Malaysia | Lai O.-M.,University Putra Malaysia | Miskandar M.S.,Malaysian Palm Oil Board
Food and Bioprocess Technology | Year: 2012

Many studies have been conducted to deliver more healthy alternatives to full fat products. Incorporation of a high proportion of diacylglycerol oil as a functional oil into the plastic fat products through development of blend formulation is considered as one such attempt. Ternary mixtures containing sunflower oil (SFO), palm kernel olein (PKOL), and palm-based diacylglycerol oil (POL-DAG) with certain proportions were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (DSFC) using nuclear magnetic resonance and melting and crystallization properties using differential scanning calorimetry were studied. Ternary phase behavior was analyzed with isosolid diagrams. The eutectic behavior was observed along the binary line of PKOL/POL-DAG at temperature ranges of 5-20 °C. This was reflected in the lower heat of crystallization (ΔHc) as well as higher DSFC for 50/50 mixture of PKOL and POL-DAG in contrast with PKOL and POL-DAG. No eutectic interaction was observed along the binary lines of SFO/PKOL as well as SFO/POL-DAG despite showing DSFC within temperature ranges of 5-25 °C. Addition of 0%, 33. 33%, 66. 66%, and 100% of POL-DAG to 50/50 mixture of SFO/PKOL increased ΔHc, crystallization onset (T O), and SFC (at all temperatures studied) of the blends and showed no eutectic behavior. However, addition of the same amounts of PKOL to equi-mixture of SFO/POL-DAG reduced T O while ΔHc increased and showed minor eutectic behavior. Therefore, PKOL was indicated to be less compatible with POL and SFO. Palm-based DAG-enriched soft tub margarine containing SFO/PKOL/POL-DAG [35/15/50, (w/w)] was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile as well as SMP but also lower saturated fatty acid as compared with commercial soft tub margarine. © 2010 Springer Science + Business Media, LLC.

Terhem R.B.,University Putra Malaysia | Terhem R.B.,Wageningen University | van Kan J.A.L.,Wageningen University
Fungal Genetics and Biology | Year: 2015

Hydrophobins are small secreted fungal proteins that play roles in growth and development of filamentous fungi, i.e. in the formation of aerial structures and the attachment of hyphae to hydrophobic surfaces. In Botrytis cinerea, three hydrophobin genes have been identified. Studies by Mosbach et al. (2011) showed that hydrophobins are neither involved in conferring surface hydrophobicity to conidia and aerial hyphae of B. cinerea, nor are they required for virulence. The present study investigated the role of hydrophobins in sclerotium and apothecium development. Expression analysis revealed high expression of the Bhp1 gene during different stages of apothecium development. Two Bhp1 splice variants were detected that differ by an internal stretch of 13 amino acid residues. Seven different mutants in which either a single, two or three hydrophobin genes were knocked out, as well as two wild type strains of opposite mating types, were characterized for sclerotium and apothecium development. No aberrant morphology was observed in sclerotium development when single deletion mutants in hydrophobin genes were analyzed. Sclerotia of double knock out mutant δ. Bhp1/δ. Bhp3 and the triple knock out mutant, however, showed easily wettable phenotypes. For analyzing apothecium development, a reciprocal crossing scheme was setup. Morphological aberrations were observed in crosses with two hydrophobin mutants. When the double knock out mutant δ. Bhp1/δ. Bhp2 and the triple knock out mutant were used as the maternal parent (sclerotia), and fertilized with wild type microconidia, the resulting apothecia were swollen, dark brown in color and had a blotched surface. After initially growing upwards toward the light source, the apothecia in many cases collapsed due to loss of structural integrity. Aberrant apothecium development was not observed in the reciprocal cross, when these same mutants were used as the paternal parent (microconidia). These results indicate that the presence of hydrophobins in maternal tissue is important for normal development of apothecia of B. cinerea. © 2014 Elsevier Inc.

Malaysian Palm Oil Board and University Putra Malaysia | Date: 2012-11-07

A method to produce hydrazide from triacylglycerol, the method includes steps of mixing vegetable oil with an organic solvent in a reactor forming a mixture, adding hydrazinemonohydrate into the mixture, stirring the mixture, adding catalyst, stirring the mixture to form hydrazide and separating the hydrazide from the mixture. Most illustrative drawing:

Arai T.,University of Tokyo | Arai T.,University Putra Malaysia | Chino N.,University of Tokyo
Journal of Fish Biology | Year: 2012

The freshwater eels of the genus Anguilla, which are catadromous, migrate between freshwater growth habitats and offshore spawning areas. A number of recent studies, however, found examples of the temperate species Anguilla anguilla, Anguilla rostrata, Anguilla japonica, Anguilla australis and Anguilla dieffenbachii that have never migrated into fresh water, spending their entire life history in the ocean. Furthermore, those studies found an intermediate type between marine and freshwater residents, which appear to frequently move between different environments during their growth phase. The discovery of marine and brackish-water residents Anguilla spp. suggests that they do not all have to be catadromous, and it calls into question the generalized classification of diadromous fishes. There has been little available information, however, concerning migration in tropical Anguilla spp. Anguilla marmorata, shows three fluctuation patterns: (1) continuous residence in fresh water, (2) continuous residence in brackish water and (3) residence in fresh water after recruitment, while returning to brackish water. Such migratory patterns were found in other tropical species, Anguilla bicolor bicolor and Anguilla bicolor pacifica. In A. b. bicolor collected in a coastal lagoon of Indonesia, two further patterns of habitat use were found: (1) constantly living in either brackish water or sea water with no freshwater life and (2) habitat shift from fresh water to brackish water or sea water. The wide range of environmental habitat use indicates that migratory behaviour of tropical Anguilla spp. is facultative among fresh, brackish and marine waters during their growth phases after recruitment to the coastal areas. Further, the migratory behaviours of tropical Anguilla spp. appear to differ in each habitat in response to inter and intra-specific competition. The results suggest that tropical Anguilla spp. have a flexible pattern of migration, with an ability to adapt to various habitats and salinities. The ability of anguillids to reside in environments of various salinities would be a common feature between tropical and temperate species without a latitudinal cline. Thus, the migration of Anguilla spp. into fresh water is clearly not an obligatory behaviour. This evidence of geographical variability among Anguilla spp. suggests that habitat use is determined by environmental conditions in each site. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Hajeb P.,University Putra Malaysia | Sloth J.J.,Technical University of Denmark | Shakibazadeh S.,University Putra Malaysia | Mahyudin N.A.,University Putra Malaysia | Afsah-Hejri L.,University Putra Malaysia
Comprehensive Reviews in Food Science and Food Safety | Year: 2014

Toxic elements such as mercury, arsenic, cadmium, and lead, sometimes called heavy metals, can diminish mental and central nervous system function; elicit damage to blood composition as well as the kidneys, lungs, and liver; and reduce energy levels. Food is considered one of the main routes of their entry into the human body. Numerous studies have been performed to examine the effects of common food processing procedures on the levels of toxic elements in food. While some studies have reported negative effects of processing, several have shown that processing practices may have a positive effect on the reduction of toxic elements in foodstuffs. A number of studies have also introduced protocols and suggested chemical agents that reduce the amount of toxic elements in the final food products. In this review, the reported methods employed for the reduction of toxic elements are discussed with particular emphasis on the chemical binding of both the organic and inorganic forms of each element in various foods. The molecular groups and the ligands by which the food products bind with the metals and the types of these reactions are also presented. © 2014 Institute of Food Technologists.

Althuwaynee O.F.,University Putra Malaysia | Pradhan B.,University Putra Malaysia | Park H.-J.,Sejong University | Lee J.H.,Sejong University
Catena | Year: 2014

This study compares the landslide susceptibility maps from four application models, namely, (1) the bivariate model of the Dempster-Shafer based evidential belief function (EBF); (2) integration of the EBF in the knowledge-based analytical hierarchy process (AHP) as a pairwise comparison model processed by using all available causative factors; (3) integration of the EBF in the knowledge-based AHP as a pairwise comparison model by using high nominated causative factor weights only; and (4) integrated EBF in the logistic regression (LR) as a multivariate model by using nominated causative factor weights only. These models were tested in Pohang and Gyeongju Cities (South Korea) by using the geographic information system GIS platform. In the first step, a landslide inventory map consisting of 296 landslide locations were prepared from various data sources. Then, a total of 15 landslide causative factors (slope angle, slope aspect, curvature, surface roughness, altitude, distance from drainages, stream power index, topographic wetness index, wood age, wood diameter, wood type, forest density, soil thickness, soil texture, and soil drainage) were extracted from the database and then converted into a raster. Final susceptibility maps exhibit close results from the two models. Models 1 and 3 predicted 82.3% and 80% of testing data during the analysis, respectively. Thus, Models 1 and 3 show better performance than LR. These resultant maps can be used to extend the capability of bivariate statistical based model, by finding the relationship between each single conditioning factor and landslide locations, moreover, the proposed ensemble model can be used to show the inter-relationships importance between each conditioning factors, without the need to refer to the multivariate statistic. The research outcome may provide powerful tools for natural hazard assessment and land use planning. © 2013 Elsevier B.V.