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Universiti Teknologi Malaysia is the oldest public engineering and technological university in Malaysia. The university specializes in technical studies, with separate faculties for the engineering divisions such as Civil, Mechanical, Electrical, Chemical and Biomedical engineering. It also has faculties for Education, Pure science, Management, and Human Resources Development. It is the country's major source of graduate engineers and similar professionals.With over 20,000 students on campus, more than 25% of them are postgraduates. Since the 1990s, the number of foreign students, particularly from neighbouring Asian countries, the Middle East, and Africa, has been increasing, especially in postgraduate programs. UTM graduates have gone on to many academic and professional institutions across the world.Universiti Teknologi Malaysia is located in Kuala Lumpur, the capital city of Malaysia, and Johor Bahru, the southern city in Iskandar Malaysia, in the south of Peninsular Malaysia. Wikipedia.

This article presents a comprehensive kinetic model for thermal cracking of waste cooking oil using monomolecular lumped kinetics. The chemical lumps were classified on the basis of carbon number range of the hydrocarbons and a first order irreversible monomolecular cracking kinetics was considered for finding the product concentration in a reactor. Arrhenius kinetic law was applied for determining temperature dependency of the apparent kinetic constants included in the model. The parameter reduction was performed by calculating the preexponential factors through transition state theory and statistical thermodynamics concepts. The activation energy of the reactions was estimated through hybrid optimization using experimental data available in the literature. The proposed kinetic model for thermal cracking of waste cooking oil exhibits good agreement with the experimental data. Furthermore, the present kinetic analysis reveals that all parallel reactions from waste cooking oil are dominant for producing hydrocarbons in a product lump as compared to reactions in series and further cracking of product lumps. © 2015 Elsevier Ltd. All rights reserved.

Kanniah K.D.,University of Technology Malaysia | Beringer J.,Monash University | Hutley L.,Charles Darwin University
Agricultural and Forest Meteorology | Year: 2013

The control of clouds on the canopy gross primary productivity (GPP) was examined at Howard Springs, a tropical savanna site in the Northern Territory, Australia. It was demonstrated in this study that cloudiness can increase the initial canopy quantum efficiency (α), midday light use efficiency (LUE) and water use efficiency (WUE), but decrease GPP in savannas. Thick clouds (clearness index of 0-0.3 in the wet season produced much more diffuse fraction of Photosynthetically Active Radiation (fDPAR. >. 80%), which caused increases in α by 24% and 62% compared to thin clouds (fDPAR between 30% and 80%) and clear sky (fDPAR. <. 30%) conditions respectively. The influence of environmental conditions shows that under similar vapour pressure deficit, temperature and soil water content classes, α values were significantly higher under thick clouds compared to thin clouds or clear skies. This indicates the importance of diffuse radiation in enhancing LUE even within similar environmental conditions. However, the enhanced LUE under cloudy skies is insufficient to increase GPP due to the dramatic decline in total radiation. Therefore, it can be concluded that the quantity of solar radiation is more critical than the quality of radiation in savannas. However, savanna ecosystems appear to be well adapted to the environment where a 63% decrease in PAR only reduced GPP by 26%. These findings highlight the importance of clouds as a critical factor in determining savanna productivity that has implications for savannas carbon cycle. © 2013 Elsevier B.V.

Barau A.S.,University of Technology Malaysia
Habitat International | Year: 2015

Household perception of urban greenery is a vehicle for understanding socio-ecological dimensions of grassroots urban sustainability. It also helps in advancing public participation in urban green infrastructure initiatives. The present study measures public perception of urban households using questionnaire survey and observations of how people maintain plants in and around their homes and neighbourhoods in parts of Johor Bahru, Malaysia. The selection of the participating households reflects on Malaysia's racial composition of which about 60% is Malay, 30% Chinese, and 10% Indians respectively. The study compares gender, age, and job status of the respondents against 14 variables to determine perceptions on socio-ecological aspects of plant keeping practices. The Rasch model's Wright map and differential item functioning (DIF) were used to analyse the respondents' perceptions. The findings revealed that on average, households with the least number of plants keep 1-9 species, while those with the highest number keep over 30 plant species. In respect of ecosystem services, the three racial groups maintain plants for aesthetics, culinary, socio-cultural and spiritual purposes. Finally, the study underscores the need for urban planning authorities and urban landscape managers to encourage and engage households as part of strategies for streamlining and mainstreaming urban resilience and transformation to urban sustainability. © 2015 Elsevier Ltd.

Oehlers D.J.,University of Adelaide | Muhamad R.,University of Technology Malaysia | Mohamed Ali M.S.,University of Adelaide
Construction and Building Materials | Year: 2013

Flexural ductility in reinforced concrete members may be defined as concentrations of rotation at discrete points. As such, flexural ductility affects the serviceability deflection of RC beams once flexural cracking, in which there is a discrete rotation between the crack faces, has occurred and which is the subject of this paper. Design rules for quantifying the deflection of steel reinforced RC beams and slabs are generally based on a full-interaction moment-curvature (M/χ) approach that requires the flexural rigidity to be calibrated empirically. Being empirically based, these design rules should only be applied within the bounds of the tests from which they were derived that is for steel reinforcement in which the modulus is fairly constant and with ribbed bars which have a very good bond with the concrete. These bounds do not apply to FRP reinforcing bars where the modulus can vary enormously depending on the type and density of fibre and where the bond between the FRP reinforcement and concrete can also vary widely depending on the manufacturing process. Hence it is both difficult and expensive to quantify empirically, using the M/χ approach, the deflection of RC beams with FRP reinforcement due to the very wide range of these variables. In this paper, an alternative mechanics based discrete rotation approach for the non-time dependent deflection is developed for FRP reinforced flexural members and which is validated by FRP RC beam tests. Being mechanics based, this discrete rotation approach can cope with any type of FRP reinforcing bar with any type of bond characteristic. As with the M/χ approach, the material properties are determined by tests but unlike the M/χ approach in which the flexural rigidity, which is a major component of the model, has to be calibrated through tests, no component of this discrete-rotation model has to be determined experimentally. As this is a generic approach and can be used for any type of reinforcement and bond, this mechanics approach should speed up the development of new FRP products and the development of accurate design rules for deflection for these new FRP products. © 2012 Elsevier Ltd. All rights reserved.

Hadibarata T.,University of Technology Malaysia | Kristanti R.A.,Yamanashi University
Journal of Environmental Management | Year: 2012

The biodegradation of benzo[. a]pyrene (B. aP) by using Polyporus sp. S133, a white-rot fungus isolated from oil-contaminated soil was investigated. Approximately 73% of the initial concentration of B. aP was degraded within 30 d of incubation. The isolation and characterization of 3 metabolites by thin layer chromatography, column chromatography, and UV-vis spectrophotometry in combination with gas chromatography-mass spectrometry, indicated that Polyporus sp. S133 transformed B. aP to B. aP-1,6-quinone. This quinone was further degraded in 2 ways. First, B. aP-1,6-quinone was decarboxylated and oxidized to form coumarin, which was then hydroxylated to hydroxycoumarin, and finally to hydroxyphenyl acetic acid by addition of an epoxide group. Second, Polyporus sp. S133 converted B. aP-1,6-quinone into a major product, 1-hydroxy-2-naphthoic acid. During degradation, free extracellular laccase was detected with reduced activity of lignin peroxidase, manganese-dependent peroxidase and 2,3-dioxygenase, suggesting that laccase and 1,2-dioxygenase might play an important role in the transformation of PAHs compounds. © 2012.

Brighenti F.,Karlsruhe Institute of Technology | Kamaruzaman N.,Karlsruhe Institute of Technology | Kamaruzaman N.,University of Technology Malaysia | Brandner J.J.,Karlsruhe Institute of Technology
Applied Thermal Engineering | Year: 2013

Electronic systems require cooling devices that are able to deal with high heat-flux capabilities. For this purpose, microchannels are attractive for direct cooling, due to their superior performances. A study on self-similar heat sinks for liquid cooled electronics is presented in this work, where the devices are made from copper, designed for industrial application and for large scale production. Self-similarity refers to the fact that there is a certain similarity and repeatability (or pattern) of the substructures compared with the overall structure. The internal structures, the so called overflow structures (or microchannels), have been designed in order to achieve high heat transfer coefficients. To validate the design and describe the flow characteristics inside the device via analytical solutions is almost impossible, therefore a well known numerical code was employed to have an insight of the thermal-fluid distributions. As can be seen clearly from the simulation, most of the heat is removed in the overflow-structure, on the side of the device adjacent to the source of heat. This paper attempts to analyse a comprehensive list of data as well as plots in a critical manner in order to illustrate the significant characteristics of this type of device. A clear lack in a proper common definition of the heat flux may lead to a misinterpretation of the results, in fact depending on the chosen area where the heat exchange takes place (namely the internal area of the microstructures or the separation surface between the device and the heating source), we can achieve a maximum heat flux of either about 200 W/cm2 or about 700 W/cm2. A very low pressure drop together with a good heat removal capability, make this device suitable for cooling of IGBT chips in power electronic applications. © 2013 Elsevier Ltd. All rights reserved.

Kidam K.,Aalto University | Kidam K.,University of Technology Malaysia | Hurme M.,Aalto University
Process Safety and Environmental Protection | Year: 2013

A database study of chemical process accident cases was carried out. The objective of the study is was to identify the reasons for equipment based accidents. The most frequent accident causing equipment were piping (25%), reactors and storage tanks (both 14%) and process vessels (10% of equipment accidents). The six most accident-prone equipment is process related involve nearly 80% of accidents. 78% of equipment accident contributors are technically oriented including design and human/technical interface faults. Purely human and organizational reasons are the most common accident contributors for storage tanks (33%), piping (18%) and heat transfer equipment (16% of causes). For other equipment the technical accident causes are most common. The accident contributors were divided to main and sub-contributors. On average process equipment failures have 2.2 contributors. The contributors, which frequent and act often as main contributors, should be focused. These risky contributors were identified for several equipment types. Also a deeper analysis of the accident causes and their interconnections was made. Based on the analysis a checklist of main risk factors was created for hazard identification on different types of equipment. © 2012 The Institution of Chemical Engineers.

Mussa M.A.,National University of Malaysia | Abdullah S.,National University of Malaysia | Nor Azwadi C.S.,University of Technology Malaysia | Muhamad N.,National University of Malaysia
Computers and Fluids | Year: 2011

This paper presents the simulation of natural heat convection in an enclosure using Cubic-Interpolated-Pseudo-Particle (CIP) lattice-Boltzmann method. A D2Q9 lattice model was coupled with the simplest D2Q4 lattice model to represent density and internal energy distribution function, respectively. The effects of the Rayleigh number on the flow pattern were studied. The enclosure is filled with air heated by a small localized source of heat at two different positions on the bottom wall. The results explain the mechanism of natural convection rate increasing due to the Rayleigh number and heat source position changing. The comparison of the results was in excellent agreement with results from the literature. © 2011 Elsevier Ltd.

Wahidin S.,University of Kuala Lumpur | Idris A.,University of Technology Malaysia | Shaleh S.R.M.,Universiti Malaysia Sabah
Bioresource Technology | Year: 2013

Illumination factors such as length of photoperiod and intensity can affect growth of microalgae and lipid content. In order to optimize microalgal growth in mass culture system and lipid content, the effects of light intensity and photoperiod cycle on the growth of the marine microalgae, Nannochloropsis sp. were studied in batch culture. Nannochloropsis sp. was grown aseptically for 9days at three different light intensities (50, 100 and 200μmolm-2s-1) and three different photoperiod cycles (24:0, 18:06 and 12:12h light:dark) at 23°C cultivation temperature. Under the light intensity of 100μmolm-2s-1 and photoperiod of 18h light: 6h dark cycle, Nannochloropsis sp. was found to grow favorably with a maximum cell concentration of 6.5×107cellsmL-1, which corresponds to the growth rate of 0.339d-1 after 8day cultivation and the lipid content was found to be 31.3%. © 2012 Elsevier Ltd.

Kherbeet A.Sh.,University of Tenaga Nasional | Mohammed H.A.,University of Technology Malaysia | Salman B.H.,University of Tenaga Nasional
International Journal of Heat and Mass Transfer | Year: 2012

Laminar mixed convection flow over a 2D horizontal microscale backward-facing step (MBFS) placed in a duct is numerically investigated. The governing equations along with the boundary conditions are solved using the finite volume method (FVM). The upstream wall and the step wall are considered adiabatic, while the downstream wall is heated by uniform heat flux. The straight wall of the duct is maintained at a constant temperature that is higher than the inlet fluid temperature. Different types of nanoparticles such as Al 2O 3, CuO, SiO 2 and ZnO, with volume fractions in the range of 1-4% are used. The nanoparticles diameter was in the range of 25 nm ≤ d p ≤ 70 nm. The expansion ratio was 2 and the step height was 0.96 μm. The Reynolds number was in the range of 0.05 ≤ Re ≤ 0.5. The results revealed that the Nusselt number increases with increasing the volume fraction and Reynolds number. The nanofluid of SiO 2 nanoparticles is observed to have the highest Nusselt number value. It is also found that the Nusselt number increases with the decrease of nanoparticle diameter. However, there is no recirculation region was observed at the step and along the duct. © 2012 Elsevier Ltd. All rights reserved.

Zeinali M.,Malaysia Japan International Institute of Technology | Mazlan S.A.,Malaysia Japan International Institute of Technology | Abd Fatah A.Y.,Malaysia Japan International Institute of Technology | Zamzuri H.,University of Technology Malaysia
Smart Materials and Structures | Year: 2013

A magnetorheological (MR) damper is a promising appliance for semi-active suspension systems, due to its capability of damping undesired movement using an adequate control strategy. This research has been carried out a phenomenological dynamic model of two MR dampers using an adaptive-network-based fuzzy inference system (ANFIS) approach. Two kinds of Lord Corporation MR damper (a long stroke damper and a short stroke damper) were used in experiments, and then modeled using the experimental results. In addition, an investigation of the influence of the membership function selection on predicting the behavior of the MR damper and obtaining a mathematical model was conducted to realize the relationship between input current, displacement, and velocity as the inputs and force as output. The results demonstrate that the proposed models for both short stroke and long stroke MR dampers have successfully predicted the behavior of the MR damper with adequate accuracy, and an equation is presented to precisely describe the behavior of each MR damper. © 2013 IOP Publishing Ltd.

Dennyson Savariraj A.,Pusan National University | Viswanathan K.K.,University of Technology Malaysia | Prabakar K.,Pusan National University
ACS Applied Materials and Interfaces | Year: 2014

Knit-coir-mat-like structured CuS thin films prepared by chemical bath deposition with different time duration were used as counter electrode in qunatum dot sensitized solar cells. The film deposited at 4 h exhibited better electrochemical and photovoltaic performance with JSC, VOC, and FF values of 14.584 mA cm-2, 0.566 V, and 54.57% and efficiency of 4.53%. From the UV-vis absorption spectra, it is observed that CuS thin film exhibits free carrier intraband absorption in the longer wavelengh region. The enhanced performance of CuS counter electrodes is due to Cu vacancies with increased S composition, and the quasi-Fermi energy level in semiconductors with respect to electrolyte redox potential is one of the causes that affects the electrocatalytic activity of counter electrodes. (Chemical Equation Presented). © 2014 American Chemical Society.

Reza Dousti M.,Islamic Azad University at Tehran | Raheleh Hosseinian S.,University of Technology Malaysia
Journal of Luminescence | Year: 2014

Dy3+-doped lead sodium tellurite glasses containing silver nanoparticles (NPs) were synthesized by a melt-quenching technique and treated for different annealing time intervals above the glass transition temperature. The glass samples were characterized by UV-vis-IR absorption spectroscopy, photoluminescence spectroscopy and transmission electron microscope imaging. Eight absorption peaks of Dy3+ ions were observed indicating the transitions from ground state to different excited states. The surface plasmon resonance (SPR) peak of silver NPs was probed at 522 nm. Blue, yellow and red luminescence emissions were recorded at 485, 578 and 665 nm. The intensity of emission peaks for heat-treated samples containing silver NPs found to be 1.7-4 times larger than their singly-doped counterpart. Such enhancements are attributed to the modification of the local field due to difference between dielectric constants of metal and surrounding medium as the major factor, and energy transfer from nano-metal particles to Dy3+ ions as the minor aspect. The size distribution of silver NPs has a Gaussian shape with a maximum around 18 nm. The glasses can be nominated as promising materials for solid state lasers. © 2014 Elsevier B.V. All rights reserved.

Low K.O.,Multimedia University | Wong K.J.,University of Technology Malaysia
Tribology International | Year: 2011

In this paper, the application of ball burnishing as a new surface treatment process for polymers is investigated. The polymers used were polyoxymethylene (POM) and polyurethane (PUR). The lowest surface roughness value achieved for POM was 0.44 μm (45% decrease) and for PUR was 0.46 μm (42% decrease). The lowest coefficient of friction value achieved was 0.22 (32.9% decrease) for POM and 0.24 (28.8% decrease) for PUR. The lowest specific wear rate value achieved was 0.31×10-6 mm3/N m (38.6% decrease) for POM and 0.41×10-6 mm3/N m (37.9% decrease) for PUR. © 2010 Elsevier Ltd.

Rusbintardjo G.,Islamic University of Sultan Agung | Hainin M.R.,University of Technology Malaysia | Yusoff N.I.M.,National University of Malaysia
Construction and Building Materials | Year: 2013

This study was conducted to investigate the suitability of using oil palm fruit ash (OPFA) as a bitumen modifier. The OPFA was used to fulfil all bitumen modification requirements, as well as to take advantage of a waste by-product of the palm oil mill industry which could help to reduce environmental pollution. Twenty-four OPFA-modified bitumens (OPFA-MBs) were produced by the laboratory mixing of normal bitumen (80/100) from two sources with Fine and Coarse OPFAs of six different contents. This process was conducted at a mixing temperature of 160 C, a mixing time of 60 min and a mixing stirring speed of 800 rpm. The consistency and rheological characteristics of the OPFA-MBs were analysed by means of conventional as well as dynamic mechanical analysis using dynamic shear rheometer (DSR), bending beam rheometer (BBR) and direct tension test (DTT). The results of the investigation indicate that binder compounded with OPFA becomes less susceptible to temperature, improve resistance to rutting at 70 C, fatigue cracking at 20 C, and thermal cracking at -17 C of the surface pavement temperature compared to the unmodified bitumen. The OPFA-MB can be categorised as a binder with penetration grade of 60/70 or as PG 70-16 in the performance based system. Finally, it can be deduced that it is feasible to use OPFA as a modifier of bitumen.© 2013 Elsevier Ltd. All rights reserved.

Hermawan H.,University of Technology Malaysia | Hermawan H.,Laval University | Mantovani D.,Laval University
Acta Biomaterialia | Year: 2013

Biodegradable stents are considered to be a recent innovation, and their feasibility and applicability have been proven in recent years. Research in this area has focused on materials development and biological studies, rather than on how to transform the developed biodegradable materials into the stent itself. Currently available stent technology, the laser cutting-based process, might be adapted to fabricate biodegradable stents. In this work, the fabrication, characterization and testing of biodegradable Fe-Mn stents are described. A standard process for fabricating and testing stainless steel 316L stents was referred to. The influence of process parameters on the physical, metallurgical and mechanical properties of the stents, and the quality of the produced stents, were investigated. It was found that some steps of the standard process such as laser cutting can be directly applied, but changes to parameters are needed for annealing, and alternatives are needed to replace electropolishing. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Bhutta M.A.R.,University of Technology Malaysia | Maruya T.,Taisei Corporation | Tsuruta K.,Research and Development Center
Construction and Building Materials | Year: 2013

Chloride diffusion is one of the main factors that affect concrete durability in harsh Arabian Gulf environment. This happens due to severe ground and ambient salinity and large fluctuations in temperature and humidity regimes and shortening the life span of the concrete structures. To study the performance of polymer-impregnated concrete permanent form (PICPF) to prevent chloride penetration, polymer-impregnated concrete panels (450 × 900 × 25 mm) were prepared as permanent forms for large-scale retaining reversible T-shaped reinforced concrete walls (Standard concrete wall and concrete wall covered with PICPF) and exposed to extremely aggressive environment site of the port city, Al Jubail, Saudi Arabia for more than 10 years. The foundation and lower half part of concrete walls were embedded into ground near the sea. This study focused on the use of PICPF in marine environment to prevent chloride ions penetration from atmosphere, ground and sea. The performance of PICPF to protect large-scale concrete walls from chloride attack from ground, atmosphere and sea was evaluated; core specimens were taken from concrete walls after 1.5-year, 5.4-year and 10.6-year outdoor exposure, and tested for carbonation depth, chloride ions penetration depth, and compressive strength. It was found that covering all surfaces of concrete walls with PICPF proved to be much effective in controlling water evaporation from concrete walls to atmosphere and to protect chloride attack from atmosphere, underground water and sea. © 2013 Elsevier Ltd. All rights reserved.

Shabri A.,University of Technology Malaysia | Suhartono,Sepuluh Nopember Institute of Technology
Hydrological Sciences Journal | Year: 2012

This paper investigates the ability of a least-squares support vector machine (LSSVM) model to improve the accuracy of streamflow forecasting. Cross-validation and grid-search methods are used to automatically determine the LSSVM parameters in the forecasting process. To assess the effectiveness of this model, monthly streamflow records from two stations, Tg Tulang and Tg Rambutan of the Kinta River in Perak, Peninsular Malaysia, were used as case studies. The performance of the LSSVM model is compared with the conventional statistical autoregressive integrated moving average (ARIMA), the artificial neural network (ANN) and support vector machine (SVM) models using various statistical measures. The results of the comparison indicate that the LSSVM model is a useful tool and a promising new method for streamflow forecasting.Editor D. Koutsoyiannis; Associate editor L. SeeCitation Shabri, A. and Suhartono, 2012. Streamflow forecasting using least-squares support vector machines. Hydrological Sciences Journal, 57 (7), 1275-1293. © 2012 Copyright 2012 IAHS Press.

Lee H.V.,University Putra Malaysia | Yunus R.,University Putra Malaysia | Juan J.C.,University of Technology Malaysia | Taufiq-Yap Y.H.,University Putra Malaysia
Fuel Processing Technology | Year: 2011

Abstract Biodiesel of non food vegetal oil origin is gaining attention as a replacement for current fossil fuels as its non-food chain interfering manufacturing processes shall prevent food source competition which is expected to happen with current biodiesel production processes. As a result, non edible Jatropha curcas plant oil is claimed to be a highly potential feedstock for non-food origin biodiesel. CaO-MgO mixed oxide catalyst was employed in transesterification of non-edible J. curcas plant oil in biodiesel production. Response surface methodology (RSM) in conjunction with the central composite design (CCD) was employed to statistically evaluate and optimize the biodiesel production process. It was found that the production of biodiesel achieved an optimum level of 93.55% biodiesel yield at the following reaction conditions: 1) Methanol/oil molar ratio: 38.67, 2) Reaction time: 3.44 h, 3) Catalyst amount: 3.70 wt.%, and 4) Reaction temperature: 115.87 °C. In economic point of view, transesterification of J. curcas plant oil using CaO-MgO mixed oxide catalyst requires less energy which contributed to high production cost in biodiesel production. The incredibly high biodiesel yield of 93.55% was proved to be the synergetic effect of basicity between the active components of CaO-MgO shown in the physicochemical analysis. © 2011 Elsevier B.V. All rights reserved.

Nasir M.H.N.M.,University of Malaya | Sahibuddin S.,University of Technology Malaysia
International Journal of Physical Sciences | Year: 2011

A five-round Delphi study was conducted to determine the degree to which the Team Software Process (TSP) can address the identified critical success factors for software projects. Three high-reputation and high-calibre experts participated in this study. Our results found agreement among the experts that the TSP provided the 'Best Practises' for addressing 14 critical success factors. The experts also agreed that the TSP provided a 'Very Good' framework for addressing 4 critical success factors. Our findings further suggested that 6 critical success factors were addressed by the TSP at a 'Good' level; only 1 critical success factor was addressed to a limited degree and none of the critical success factors were addressed at the 'Fair' level. The only critical success factor not addressed by the TSP was the 'good performance by vendors/contractors/consultants' factor. From an expert's perspective, the TSP provides an operational framework that addresses 21 critical success factors software projects. We believe that each framework or method on its own cannot address all the identified critical success factors. However, by combining a software process improvement and project management framework or other excellent software development process models, all of the critical success factors can be better addressed.

Marghany M.,University of Technology Malaysia
International Journal of Physical Sciences | Year: 2011

Polarized sensor is able to investigate the coastal problems such as erosion and sedimentation. AIRSAR polarized sensor could be an ideal concept in developing such sensor. In this context, this work is introducing a new approach for modeling the rate of shoreline deformation from AIRSAR Cvv band. The hologram algorithm has been applied to simulate the wave spectra propagation pattern. The results show that the phase information of AIRSAR hologram image can be used to simulate the wave refraction pattern. Thus, the rate of shoreline deformation is ranged between -0.005 to 1.0 m with bias of -0.06 m and standard error of ± 0.042 m. In conclusion, there is an excellent promise which is introduced by holograhic interferometry to model the deformation of shoreline. ©2011 Academic Journals.

Adnan M.A.,University of Technology Malaysia
Sensors (Basel, Switzerland) | Year: 2013

For the past 20 years, many authors have focused their investigations on wireless sensor networks. Various issues related to wireless sensor networks such as energy minimization (optimization), compression schemes, self-organizing network algorithms, routing protocols, quality of service management, security, energy harvesting, etc., have been extensively explored. The three most important issues among these are energy efficiency, quality of service and security management. To get the best possible results in one or more of these issues in wireless sensor networks optimization is necessary. Furthermore, in number of applications (e.g., body area sensor networks, vehicular ad hoc networks) these issues might conflict and require a trade-off amongst them. Due to the high energy consumption and data processing requirements, the use of classical algorithms has historically been disregarded. In this context contemporary researchers started using bio-mimetic strategy-based optimization techniques in the field of wireless sensor networks. These techniques are diverse and involve many different optimization algorithms. As far as we know, most existing works tend to focus only on optimization of one specific issue of the three mentioned above. It is high time that these individual efforts are put into perspective and a more holistic view is taken. In this paper we take a step in that direction by presenting a survey of the literature in the area of wireless sensor network optimization concentrating especially on the three most widely used bio-mimetic algorithms, namely, particle swarm optimization, ant colony optimization and genetic algorithm. In addition, to stimulate new research and development interests in this field, open research issues, challenges and future research directions are highlighted.

Ismail Z.H.,University of Technology Malaysia | Dunnigan M.W.,Heriot - Watt University
IET Control Theory and Applications | Year: 2011

This study presents a novel tracking control scheme for an underwater vehicle-manipulator system (UVMS) where the proposed controller is not only used to track the prescribed sub-region but also allows the use of the self-motion to perform various sub-tasks (i.e. drag minimisation, obstacle avoidance and manipulability) because of the kinematically redundant system. In the proposed control scheme, the desired primary task of the UVMS is specified as two sub-regions that are assigned for the vehicle and end-effector. Despite the parametric uncertainty associated with the underwater dynamic model, the controller ensures the sub-task tracking without affecting the sub-region and attitude tracking control objective. The Lyapunov-type approach is utilised to design the controller and an extension to an adaptive-robust control scheme with multiple sub-regions and sub-task objectives is also performed to illustrate the flexibility of the approach. The presence of variable ocean currents creates hydrodynamic forces and moments that are not well known or predictable, even though they are bounded. Therefore the control task of tracking a prescribed sub-region trajectory is challenging because of these additive bounded disturbances. Furthermore, multiple sub-task criteria that are formulated using a weighted-sum approach are added to the control objective. Simulation results are presented to demonstrate the performance of the proposed control law. © 2011 The Institution of Engineering and Technology.

Salman B.H.,University of Tenaga Nasional | Mohammed H.A.,University of Technology Malaysia | Kherbeet A.S.,University of Tenaga Nasional
International Communications in Heat and Mass Transfer | Year: 2012

In this paper, laminar convective heat transfer in a two-dimensional microtube (MT) with 50μm diameter and 250μm length with constant heat flux is numerically investigated. The governing (continuity, momentum and energy) equations were solved using the finite volume method (FVM) with the aid of SIMPLE algorithm. Different types of nanofluids Al 2O 3, CuO, SiO 2 and ZnO, with different nanoparticle size 25, 45, 65 and 80nm, and different volume fractions ranged from 1% to 4% using ethylene glycol as a base fluid were used. This investigation covers Reynolds number in the range of 10 to 1500. The results have shown that SiO 2-EG nanofluid has the highest Nusselt number, followed by ZnO-EG, CuO-EG, Al 2O 3-EG, and lastly pure EG. The Nusselt number for all cases increases with the volume fraction but it decreases with the rise in the diameter of nanoparticles. In all configurations, the Nusselt number increases with Reynolds number. © 2012 Elsevier Ltd.

Leow C.Y.,Imperial College London | Leow C.Y.,University of Technology Malaysia | Ding Z.,Newcastle University | Leung K.K.,Imperial College London | Goeckel D.L.,University of Massachusetts Amherst
IEEE Transactions on Wireless Communications | Year: 2011

We consider a scenario where multiple pairs of users exchange information within pair, with the help of a dedicated multi-antenna relay. The protocol integrates the idea of analogue network coding in mixing two data streams originating from the same user pair, together with the spatial multiplexing of the data streams originating from different user pairs. The key feature of the protocol is that it enables both the relay and the users to participate in interference cancellation. We propose several beamforming schemes for the multi-antenna relay and evaluate the performance using information theoretical metrics such as ergodic capacity, outage probability and diversity and multiplexing tradeoff. Analytical and simulation results justify that the ergodic capacity, outage probability and diversity and multiplexing tradeoff of the proposed beamforming schemes outperform comparable schemes. © 2011 IEEE.

In this work, a Monte Carlo simulation code for the electron-beam propagation was developed using the Mott's elastic scattering cross section and the Penn's dielectric function to account for beam scatterings and energy losses. Additional steps were introduced to compute the electron density profile, the momentum distribution, and the kinetic energy deposited inside the target material due to the penetration of the beam. Details of the simulation were outlined and backscattering results were validated against available data in the literature. Various parameters that govern the simulation were discussed extensively. It was shown that the electron deposition distributions were highly non-uniform. The electron density inside the target was modified significantly due to the beam and it depleted at a few nanometers below the surface while charge accumulation occurred deeper below the surface. On the other hand, the electron momentum deposited within the workpiece showed sign of increasing average electron velocity in all directions. In terms of the kinetic energy transfer, the energy distribution reached maximum at a few nanometers below the surface. Results between gold (a conductor) and silicon (an insulator) were compared as well, and they differed in magnitude and local deposition distributions, although the overall trends of the deposition distributions were similar. © 2012 Elsevier Ltd. All rights reserved.

Doroodgar F.,University of Technology Malaysia
Sensors (Basel, Switzerland) | Year: 2014

Over-the-air dissemination of code updates in wireless sensor networks have been researchers' point of interest in the last few years, and, more importantly, security challenges toward the remote propagation of code updating have occupied the majority of efforts in this context. Many security models have been proposed to establish a balance between the energy consumption and security strength, having their concentration on the constrained nature of wireless sensor network (WSN) nodes. For authentication purposes, most of them have used a Merkle hash tree to avoid using multiple public cryptography operations. These models mostly have assumed an environment in which security has to be at a standard level. Therefore, they have not investigated the tree structure for mission-critical situations in which security has to be at the maximum possible level (e.g., military applications, healthcare). Considering this, we investigate existing security models used in over-the-air dissemination of code updates for possible vulnerabilities, and then, we provide a set of countermeasures, correspondingly named Security Model Requirements. Based on the investigation, we concentrate on Seluge, one of the existing over-the-air programming schemes, and we propose an improved version of it, named Seluge++, which complies with the Security Model Requirements and replaces the use of the inefficient Merkle tree with a novel method. Analytical and simulation results show the improvements in Seluge++ compared to Seluge.

Fulazzaky M.A.,University of Technology Malaysia | Fulazzaky M.A.,Laboratoire Des Science Of Lenvironnement
Environmental Monitoring and Assessment | Year: 2013

Biochemical oxygen demand (BOD) of the leachates originally from the different types of landfill sites was studied based on the data measured using the two manometric methods. The measurements of BOD using the dilution method were carried out to assess the typical physicochemical and biological characteristics of the leachates together with some other parameters. The linear regression analysis was used to predict rate constants for biochemical reactions and ultimate BOD values of the different leachates. The rate of a biochemical reaction implicated in microbial biodegradation of pollutants depends on the leachate characteristics, mass of contaminant in the leachate, and nature of the leachate. Character of leachate samples for BOD analysis of using the different methods may differ significantly during the experimental period, resulting in different BOD values. This work intends to verify effect of the different dilutions for the manometric method tests on the BOD concentrations of the leachate samples to contribute to the assessment of reaction rate and microbial consumption of oxygen. © 2012 Springer Science+Business Media Dordrecht.

Alzahrani S.M.,Taif University | Salim N.,University of Technology Malaysia | Abraham A.,VSB - Technical University of Ostrava | Abraham A.,Network Intelligence
IEEE Transactions on Systems, Man and Cybernetics Part C: Applications and Reviews | Year: 2012

Plagiarism can be of many different natures, ranging from copying texts to adopting ideas, without giving credit to its originator. This paper presents a new taxonomy of plagiarism that highlights differences between literal plagiarism and intelligent plagiarism, from the plagiarists behavioral point of view. The taxonomy supports deep understanding of different linguistic patterns in committing plagiarism, for example, changing texts into semantically equivalent but with different words and organization, shortening texts with concept generalization and specification, and adopting ideas and important contributions of others. Different textual features that characterize different plagiarism types are discussed. Systematic frameworks and methods of monolingual, extrinsic, intrinsic, and cross-lingual plagiarism detection are surveyed and correlated with plagiarism types, which are listed in the taxonomy. We conduct extensive study of state-of-the-art techniques for plagiarism detection, including character n-gram-based (CNG), vector-based (VEC), syntax-based (SYN), semantic-based (SEM), fuzzy-based (FUZZY), structural-based (STRUC), stylometric-based (STYLE), and cross-lingual techniques (CROSS). Our study corroborates that existing systems for plagiarism detection focus on copying text but fail to detect intelligent plagiarism when ideas are presented in different words. © 2011 IEEE.

Ya'Aini N.,Chemical Reaction Engineering Group CREG | Amin N.A.S.,Chemical Reaction Engineering Group CREG | Endud S.,University of Technology Malaysia
Microporous and Mesoporous Materials | Year: 2013

In this work, a set of hybrid catalysts were synthesized, characterized and tested for the conversion of glucose to levulinic acid. The hybrid catalysts with 1:1, 1:2 and 2:1 weight ratios of CrCl3 and HY zeolite were prepared via the wetness impregnation method. Characterization of the hybrid catalysts using XRD, FESEM, BET, FT-IR, TGA, NH3-TPD and FT-IR of adsorbed pyridine demonstrated the catalytic reaction of the hybrid catalysts was predominantly influenced by the type of acid sites (Lewis acid), amount of acid sites and strength, surface area, hierarchical porous structures and shape selectivity. Highly reactive acid sites greatly influenced the catalytic activities of glucose in producing levulinic acid. Experimental results revealed that the hybrid 1:1 catalyst exhibited the highest catalytic performance with 62% of levulinic acid yield at 160 °C in 180 min of reaction temperature and time. The hybrid 1:1 catalyst has potential to be applied for biomass conversion to levulinic acid under adequate process conditions. © 2013 Elsevier Inc. All rights reserved.

Periyasamy B.,University of Technology Malaysia
Journal of the Taiwan Institute of Chemical Engineers | Year: 2015

A flow graph theory is a method for finding the analytical solution of linear differential equations which arise in chemical kinetics through Cramer's method of determinants. This article presents the applicability of flow graph theory for deriving the analytical solution of kinetic equations which arise in modeling of complex reaction system such as hydrocracking of heavy oils. A discrete lumped model for hydrocracking of heavy oils was developed and analytical solution for the governing model equations was derived using Laplace transforms earlier. In this work, a new method involving flow graph theory was used instead of Laplace transforms. The kinetic equations which describe the performance of a hydrocracker are governed by linear differential equations and a general analytical solution was successfully derived using flow graph theory. The analytical solution obtained through flow graph theory is similar with the reported solution using Laplace transforms for the kinetic equations of hydrocracking of heavy oils. Furthermore, the relative errors between the experimental data and model calculations using analytical solution of the three lump hydrocracker model are reasonable except for few data points. © 2015 Taiwan Institute of Chemical Engineers.

Sidik N.A.C.,University of Technology Malaysia | Attarzadeh S.M.R.,The University of Engineering and Technology
International Journal of Mechanics | Year: 2011

Research on solid particle flows has been quite intensive in the past decade. The difficulties associated with accurate predictions of the interactions between the solid and surrounding fluid. Hence, in the present paper, we focus on the simulation of lid driven cavity flow containing a solid particle immersed in an incompressible fluid. In the present analysis, we adopt an Eulerian Lagrangian approach where the solid particle is treated as a point in the cavity. To achieve the accuracy, the numerical scheme for the fluid is properly chosen so that the resultant force on the solid particle can be accurately determined. Our aim is to seek further improvement on the fundamental knowledge of the trajectories of asolid particle in a lid-driven cavity. To broaden our understanding of the particle dynamics in the cavity, we also study the vortex structure in the cavity which directly influence the trajectories of solid particle.

Yunus M.A.Md.,Massey University | Yunus M.A.Md.,University of Technology Malaysia | Mukhopadhyay S.C.,Massey University
IEEE Sensors Journal | Year: 2011

This paper introduces novel sensors based on the combination of planar meander and interdigital electromagnetic sensors for monitoring the level of contamination in water sources. A series of experiments was conducted to determine the sensors characteristics. Two nitrates forms, namely sodium nitrates and ammonium nitrates, were mixed in several different ratios dissolved in 1 L of distilled water and were used to observe the response of the sensors. Initial results show that the sensors can detect very well the presence of nitrate added in distilled water. Furthermore, the contamination level of water samples which were taken from various sources and locations in New Zealand have been determined using the sensor, and the results was compared with the results obtained using nuclear magnetic resonance (NMR) technique. The outcomes show a very good correlation of contamination level with the output response of the sensor. The work and improvement for future consideration are discussed in this paper. © 2010 IEEE.

Niroumand H.,University of Technology Malaysia | Millona K.,Epoka University
Geotechnical News | Year: 2010

This session presents a survey and the performance of the role of shred geogrids in mud brick's compressive strength and a comparison of it with the normal mud bricks. Mud brick consists of clay, water and different materials. Its massive use may become an important evaluation due to its low cost and higher compressive strength compared to the concrete blocks. Many experiments conducted on earth blocks without any addition material, report about its low compressive strength. Thus, many testing on the strength of the mud brick, with different additional materials were done. These different additions may be shred tires, which consist in narrow strips of rubber. Another material is the shred geogrids, which consists in polyester strips grid. The paper articulates the change of compressive strength of mud bricks with these different additional materials. This is evident in the compressive test days 3,7,14 and 21 where the results show that due to different bricks with normal mud bricks and shred geogrids with sizes of 10cm×10cm×10cm, have 20% moisture content. The tires are one of the materials that cause environmental pollution and it is used less after consumption in the automotive industry, thus we used a cheap material for surveying the strength in mud brick. As well the geogrids are used in soil stabilization, where they have additional pieces in construction, so we used them in mud bricks. The results show that performances of mud bricks with shred geogrids were better than normal mud bricks.

Fitriadhy A.,University of Malaysia, Terengganu | Yasukawa H.,Hiroshima University | Koh K.K.,University of Technology Malaysia
Ocean Engineering | Year: 2013

This paper proposes a numerical model for analyzing the course stability of a towed ship in uniform and constant wind. The effects of an unstable towed ship and a stable towed ship were recorded using numerical analysis at various angles and velocities of wind. The stability investigation of the ship towing system was discussed using the linear analysis, where a tug's motion was assumed to be given. When the tug and the towed ship's motions were coupled through a towline as a proper model of the ship towing system, their dynamic interactions during towing was then captured using towing trajectories and analyzed using nonlinear time-domain simulation. With increasing wind velocity, the simulation results revealed that the towing instability of the unstable towed ship was recovered in the range of beam to quartering winds; however, the towing stability of the stable towed ship in head and following winds gradually degraded. It should be noted that this towing instability might have resulted in the impulsive towline tension and could led to serious towing accident e.g. towline breakage or collisions. © 2013 Elsevier Ltd. All rights reserved.

Pereira V.R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Bhat U.K.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia
Desalination | Year: 2014

Polyaniline (PANI) nanofibers were used as hydrophilic additives to study their effect on the performance of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. PVDF UF membranes were prepared by the phase inversion method with hydrolyzed polystyrene-co-maleic anhydride (H-PSMA) and PANI nanofibers as additives. PANI nanofibers were synthesized by rapid mixing reaction and were used as a hydrophilic modifying agent with varying concentrations (0-1.5 wt.%) in the membranes. The synthesized PANI nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. Hydrolyzed PSMA was prepared by the hydrolysis of PSMA and was used as a novel pore forming additive. The addition of PANI nanofibers into the membranes increased the membrane hydrophilicity, porosity, water uptake and permeability. The membranes also showed good antifouling nature during BSA (bovine serum albumin) filtration when compared to the pristine membrane without PANI nanofibers. Membrane with 1.0 wt.% PANI content showed highest permeability among the synthesized membranes. The membrane having highest permeability was subjected to heavy metal ion rejection which showed high rejection of 98.52% and 97.38% for heavy metal ions Pb2+ and Cd2+ respectively. © 2014 Elsevier B.V.

Bhutta M.A.R.,University of Technology Malaysia | Ohama Y.,Nihon University | Tsuruta K.,Materras Oume Concrete Industry Co.
Construction and Building Materials | Year: 2011

The present study examines the applicability of polymer mortar panels using a methyl methacrylate (MMA) solution of waste expanded polystyrene (EPS) to develop effective recycling processes for the EPS, referring to the strength properties of a polymer-impregnated mortar panel with almost the same performance as commercial products. An MMA solution of EPS is prepared by dissolving EPS in MMA, and unreinforced and steel fiber-reinforced polymer mortars are mixed using the EPS-MMA-based solution as a liquid resin or binder. Polymer mortar panels (PMPs) using the EPS-MMA-based polymer mortars without and with steel fiber and crimped wire cloth reinforcements and steel fiber-reinforced polymer-impregnated mortar panel (PIMP) are prepared on trial, and tested for flexural behavior under four-point loading. The EPS-MMA-based PMPs are more ductile than the PIMP, and have a high load-bearing capacity. Consequently, they can replace PIMP in practical applications. © 2010 Elsevier Ltd. All rights reserved.

Mohamad H.,University of Technology Malaysia
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Distributed strain sensing based on Brillouin Optical Time Domain Reflectometry (BOTDR) is seen as one of the most promising monitoring tools for assessing the performance of civil and geotechnical structures. Due to the distributed nature of fiber optic sensor, BOTDR not only useful to monitor the structures deformation in terms of global behavior, but also effectively detects anomalies in localized scale. Since the sensor has the ability to measure strain and temperature simultaneously, it is important that methods to separate the temperature effects are fully understood. Four known methods used to compensate temperature from BOTDR strain readings are briefly reviewed. Regardless of what method being used, this paper aims to clarify the importance of firstly calibrating the thermal characteristic of optical cables and determine the coefficient thermal expansion of the measurement host or structure. Example of BOTDR thermal measurement of an earth retaining structure is presented. © 2012 SPIE.

Marghany M.,University of Technology Malaysia
Marine Pollution Bulletin | Year: 2014

In this work, a genetic algorithm is applied for the automatic detection of oil spills. The procedure is implemented using sequences from RADARSAT-2 SAR ScanSAR Narrow single-beam data acquired in the Gulf of Mexico. The study demonstrates that the implementation of crossover allows for the generation of an accurate oil spill pattern. This conclusion is confirmed by the receiver-operating characteristic (ROC) curve. The ROC curve indicates that the existence of oil slick footprints can be identified using the area between the ROC curve and the no-discrimination line of 90%, which is greater than that of other surrounding environmental features. In conclusion, the genetic algorithm can be used as a tool for the automatic detection of oil spills, and the ScanSAR Narrow single-beam mode serves as an excellent sensor for oil spill detection and survey. © 2014 Elsevier Ltd.

Ahmad Z.A.B.,University of Technology Malaysia | Gabbert U.,Otto Von Guericke University of Magdeburg
Ultrasonics | Year: 2012

In typical Lamb wave simulation practices, effects of plate edge reflections are often not considered in order to simplify the wave signal interpretations. Methods that are based on infinite plates such as the semi-analytical finite element method is effective in simulating Lamb waves as it excludes the effect of plate edges. However, the inclusion of plate edges in a finite plate could render this method inapplicable, especially for transient response simulations. Here, by applying the ratio of Lamb mode reflections at plate edges, and representing the reflection at plate edges using infinite plate solutions, the semi-analytical finite element method can be applied for transient response simulation, even when the plate is no longer infinite. © 2012 Elsevier B.V. All rights reserved.

Hamedi M.,University of Technology Malaysia
International journal of nanomedicine | Year: 2011

The authors present a new method of recognizing different human facial gestures through their neural activities and muscle movements, which can be used in machine-interfacing applications. Human-machine interface (HMI) technology utilizes human neural activities as input controllers for the machine. Recently, much work has been done on the specific application of facial electromyography (EMG)-based HMI, which have used limited and fixed numbers of facial gestures. In this work, a multipurpose interface is suggested that can support 2-11 control commands that can be applied to various HMI systems. The significance of this work is finding the most accurate facial gestures for any application with a maximum of eleven control commands. Eleven facial gesture EMGs are recorded from ten volunteers. Detected EMGs are passed through a band-pass filter and root mean square features are extracted. Various combinations of gestures with a different number of gestures in each group are made from the existing facial gestures. Finally, all combinations are trained and classified by a Fuzzy c-means classifier. In conclusion, combinations with the highest recognition accuracy in each group are chosen. An average accuracy >90% of chosen combinations proved their ability to be used as command controllers.

Chong C.T.,University of Technology Malaysia | Hochgreb S.,University of Cambridge
Advanced Materials Research | Year: 2013

The flow field of a lab-scale model gas turbine swirl burner was characterised using particle imaging velocimetry (PIV) at atmospheric condition. The swirl burner consists of an axial swirler, a twin-fluid atomizer and a quartz tube as combustor wall. The main non-reacting swirling air flow without spray was compared to swirl flow with spray under unconfined and enclosed conditions. The introduction of liquid fuel spray changes the flow field of the main swirling air flow at the burner outlet where the radial velocity components are enhanced. Under reacting conditions, the enclosure generates a corner recirculation zone that intensifies the strength of the radial velocity. Comparison of the flow fields with a spray flame using diesel and palm biodiesel shows very similar flow fields. The flow field data can be used as validation target for swirl flame modeling. © (2013) Trans Tech Publications, Switzerland.

Ab Talib M.S.,University of Technology Malaysia | Hamid A.B.A.,University Technology of MARA
International Journal of Supply Chain Management | Year: 2014

This study is the first attempt that assembled published academic work on critical success factors (CSFs) in supply chain management (SCM) fields. The objectives of this study are to review the CSFs in SCM and to uncover the major CSFs that are apparent in SCM literatures. This study applies literature survey techniques from published CSFs studies in SCM. A collection of 42 CSFs studies in various SCM fields is obtained from major databases. The search uses keywords such as supply chain management, critical success factors, logistics management and supply chain drivers and barriers. From the literature survey, four major CSFs are proposed. The factors are collaborative partnership, information technology, top management support and human resource. It is hoped that this review will serve as a platform for future research in SCM and CSFs studies. Plus, this study contributes to existing SCM knowledge and will further appraise the concept of CSFs. © ExcelingTech Pub, UK.

Tavakolpour Saleh A.R.,Shiraz University of Technology | Mailah M.,University of Technology Malaysia
Journal of Sound and Vibration | Year: 2012

This paper introduces the concept of active support to cope with the resonance phenomenon in the flexible structures. A valid computational platform for the flexible structure was first presented via a finite difference (FD) approach. Then, the active support mechanism was applied to the simulation algorithm through which the performance of the proposed methodology in suppressing the resonance phenomenon was evaluated. The flexible structure was thus excited with the external disturbance and the system response with and without the effect of the active support was investigated through a simulation study. The simulation outcomes clearly demonstrated effective resonance suppression in the flexible structure. Finally, an experimental rig was developed to investigate the validity of the proposed technique. The experimental results revealed an acceptable agreement with the simulation outcomes through which the validity of the proposed control method was affirmed. © 2012 Elsevier Ltd. All rights reserved.

Das R.,University of Malaya | Abd Hamid S.B.,University of Malaya | Ali M.E.,University of Malaya | Ismail A.F.,University of Technology Malaysia | And 2 more authors.
Desalination | Year: 2014

The availability of safe and clean water is decreasing day by day, which is expected to increase in the coming decades. To address this problem, various water purification technologies have been adopted. Among the various concepts proposed, carbon nanotube (CNT) based water treatment technologies are the most promising because of its large surface area, high aspect ratio, greater chemical reactivity, lower cost, and energy, less chemical mass and impact on the environment. Therefore, research development and commercial interests in CNT are growing worldwide to treat water contaminants, which have huge impacts on the entire living systems including terrestrial, aquatic and aerial flora and fauna. This review discussed most of the effective CNT based water purification technologies such as adsorption, hybrid catalysis, desalination, disinfection, sensing and monitoring of three major classes such as organic, inorganic and biological water pollutants. In addition, promises, facts and challenges of these novel technologies have been critically analyzed. Special importance has been given in the transformation of environmental CNT, which could alter their generic properties, movement, cellular uptake and potential toxicity of the material in the living systems. This review would serve as a comprehensive reference source for hydrologists, membrane technologists, environmentalists and industrialists to eradicate pure water crisis in the near future. © 2014.

Othman M.F.,University of Technology Malaysia
International Review on Modelling and Simulations | Year: 2010

Predicting future behavior of a system based on its previous behaviors is one of the essential goals of modern science and it data is quite important in solving both engineering and economic problems. The objective of this paper is to develop prediction algorithms that can predict the time series data with minimum prediction error when compared with other techniques. This paper uses several artificial intelligent techniques that is fuzzy logic, multilayer perceptron neural network and generalized regression neural network (GRNN). Load demand predictions are the case studies in this project. Only short term load forecasting are being considered and two approaches have been undertaken to predict the load demand of 24 hours and 72 hours ahead. The same data are used for all techniques and the summary of their performance are compared and evaluated. © 2010 Praise Worthy Prize S.r.l.-All rights reserved.

Al-Heuseen K.,Universiti Sains Malaysia | Hashim M.R.,Universiti Sains Malaysia | Ali N.K.,University of Technology Malaysia
Applied Surface Science | Year: 2011

This article reports the properties and the behavior of GaN during the photoelectrochemical etching process using four different electrolytes. The measurements show that the porosity strongly depends on the electrolyte and highly affects the surface morphology of etched samples, which has been revealed by scanning electron microscopy (SEM) images. Peak intensity of the photoluminescence (PL) spectra of the porous GaN samples was observed to be enhanced and strongly depend on the electrolytes. Among the samples, there is a little difference in the peak position indicating that the change of porosity has little influence on the PL peak shift, while it highly affecting the peak intensity. Raman spectra of porous GaN under four different solution exhibit phonon mode E2 (high), A1 (LO), A1 (TO) and E2 (low). There was a red shift in E2 (high) in all samples, indicating a relaxation of stress in the porous GaN surface with respect to the underlying single crystalline epitaxial GaN. Raman and PL intensities were high for samples etched in H2SO4:H 2O2 and KOH followed by the samples etched in HF:HNO 3 and in HF:C2H5OH. © 2011 Elsevier B.V. All rights reserved.

Ng E.-P.,Universiti Sains Malaysia | Mohd Subari S.N.,Universiti Sains Malaysia | Marie O.,University of Caen Lower Normandy | Mukti R.R.,Bandung Institute of Technology | Juan J.-C.,University of Technology Malaysia
Applied Catalysis A: General | Year: 2013

Covalently linked sulfonic acid (SO3H) modified MCM-41 mesoporous catalysts was prepared, characterized and its catalytic activity under microwave irradiation was evaluated. The NH2-MCM-41 was first prepared by anchoring (3-aminopropyl)triethoxysilane (APTES) on Si-MCM-41 and further reacted with 1,4-butane-sultone to yield the desired acid catalyst. The mesophase and porosity of samples were determined by XRD, TEM and N2 sorption isotherm analyses. The presence of sulfonic acid moiety was confirmed by FT-IR, TG/DTA, sulfur elemental analysis and in situ IR study of pyridine and ammonia adsorptions. The catalyst showed high catalytic activity and high selectivity in tert-butylation of hydroquinone under microwave irradiation. No leaching problem was observed after several runs, while the catalyst can be recovered and reused without loss of reactivity under the described reaction conditions. © 2012 Elsevier B.V.

Chong C.T.,University of Cambridge | Chong C.T.,University of Technology Malaysia | Hochgreb S.,University of Cambridge
Proceedings of the Combustion Institute | Year: 2011

Laminar flame speeds of practical fuels including Jet-A1, diesel, palm methyl esters (PME) and blends of PME with diesel and Jet-A1 fuels are determined using the jet-wall stagnation flame configuration and particle imaging velocimetry (PIV) technique. The PME/Jet-A1 and PME/diesel blends are prepared by mixing 10%, 20% and 50% of PME with Jet-A1 and diesel fuels by volume respectively. The experiments are performed over a range of stoichiometries at elevated temperature of 470 K and atmospheric pressure under premixed conditions. The reference flame speed and imposed strain rates are determined from the two dimensional velocity profiles. Subsequently, laminar flame speeds are derived by extrapolating the reference flame speed back to zero strain rates. Experimental results are compared to experimental and simulation data from the literature for large n-alkanes and practical fuels. The results show that laminar flame speeds of Jet-A1 fuel are similar to those of n-decane and n-dodecane, indicating their potential use as surrogate fuels. Peak laminar flame speeds for diesel/air and PME/air mixtures at 470 K are similar, around 86.7 and 86.5 cm/s at equivalence ratios around 1.10 and 1.14 respectively, and that both mixtures exhibit lower flame speeds compared to n-decane and n-dodecane at fuel-leaner and stoichiometric conditions. Blending PME with Jet-A1 and diesel leads to reduced laminar flame speeds on the lean side but increased on the rich side. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

Wong B.T.,University of Technology Malaysia
International Communications in Heat and Mass Transfer | Year: 2014

Internal monochromatic acoustic phonon emission has a distinct impact on temperature distribution, as well as transient heat dissipation, depending on the emitted phonon frequency and its polarization branch. A Monte Carlo simulation of phonon transport was used to study the impact of internal acoustic phonon emission on heat dissipation at nanoscale in a silicon thin film. The cause of the emission can be due to other energy carriers or by a direct external source. The simulation utilized parabolic phonon dispersion relations in longitudinal acoustic (LA) and transverse acoustic (TA) polarizations with three phonon-phonon scatterings. The Normal and Umklapp phonon scatterings were included in the simulation. All the scattering events scatter phonons isotropically. Results indicated that monochromatic TA-phonon emission within the film tends to create higher local peak temperature than that of LA-phonon emission with an identical volumetric power generation. © 2014 Elsevier Ltd.

Marghany M.,University of Technology Malaysia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

The paper is focused on Digital Elevation Model (DEM) reconstruction from differential interferometry synthetic aperture radar (DInSAR). In doing so, conventional DInSAR procedures are implemented to three repeat passes of RADARSAT-1 SAR fine mode data (F1). Further, the multichannel MAP height estimator is implemented with phase unwrapping technique. Consequently, the multichannel MAP height estimator is used to eliminate the phase decorrelation impact from the interferograms. The study shows the performance of DInSAR method using the multichannel MAP height estimator is better than DInSAR technique which is validated by a lower range of error (0.01±0.11 m) with 90% confidence intervals. In conclusion, integration of the multichannel MAP height estimator with phase unwrapping produce accurate 3-D coastal geomorphology reconstruction. © 2012 Springer-Verlag.

Ganesh B.M.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia
Desalination | Year: 2013

Graphene oxide (GO) dispersed polysulfone (PSf) mixed matrix membranes were prepared by wet phase inversion method. The morphology of membranes was studied using scanning electron microscope (SEM) images. The variation in hydrophilicity was studied by measuring surface wettability and water swelling experiments. The performance of membranes in terms of pure water flux and salt rejection was studied. SEM images depict enhanced macrovoids, while the contact angle data reveals that, GO incorporated membrane surface is moderately hydrophilic. Membranes exhibited improved salt rejection after GO doping. Membrane with 2000ppm GO loading has exhibited maximum of 72% Na2SO4 rejection at 4bar applied pressure. The salt rejection seems to depend on pH of the feed solution and it has been witnessed that the salt rejection showed an increasing trend with increase in the pH. © 2012 Elsevier B.V.

Mustafa M.W.,University of Technology Malaysia
International Journal of Electrical Power and Energy Systems | Year: 2015

Improving the transient response of power generation systems using automation control in a precise manner is the key issue. We design a fuzzy proportional integral derivative (PID) controller using Matlab and programmable logic controllers (PLCs) for a set point voltage control problem in the automatic voltage regulator (AVR) system. The controller objective is to maintain the terminal voltage all the time under any loads and operational conditions by attaining to the desired range via the regulation of the generator exciter voltage. The main voltage control system uses PLCs to implement the AVR action. The proposed fuzzy controller combines the genetic algorithm (GA), radial-basis function network (RBF-NN) identification and fuzzy logic control to determine the optimal PID controller parameters in AVR system. The RBF tuning for various operating conditions is further employed to develop the rule base of the Sugeno fuzzy system. The fuzzy PID controller (GNFPID) is further designed to transfer in PLCs (STEP 75.5) for implementing the AVR system with improved system response. An inherent interaction between two generator terminal voltage control and excitation current is revealed. The GNFPID controller configures the control signal based on interaction and there by reduces the voltage error and the oscillation in the terminal voltage control process. We achieve an excellent voltage control performance by testing the proposed fuzzy PID controller on a practical AVR system in synchronous generator for improve the transient response. © 2015 Elsevier Ltd. All rights reserved.

Feng C.Y.,University of Ottawa | Khulbe K.C.,University of Ottawa | Matsuura T.,University of Ottawa | Ismail A.F.,University of Technology Malaysia
Separation and Purification Technology | Year: 2013

Membrane separation using hollow fibers has become one of the emerging technologies which underwent a rapid growth during the past few decades. In this article, recent progresses (last 12 years) on polymeric hollow fiber membranes have been discussed. In particular, the following topics were identified as the recent trends in the hollow fiber research. Characterizations of membrane especially by atomic force microscopy (AFM) have been reported. New hollow fiber membranes for gas-separation have been developed. New polymers and techniques have been introduced in making high performance hollow fibers. Many PVDF based membranes have been developed. Orientation of polymer molecule during spinning was also investigated. However the mechanism of orientation is not fully investigated. © 2013 Elsevier Ltd. All rights reserved.

Ebrahimi S.,University of Technology Malaysia
Proceedings - Pacific Asia Conference on Information Systems, PACIS 2012 | Year: 2012

Enterprise Resource Planning (ERP) systems, also called Enterprise Systems (ES), have received much attention from researchers and practitioners. Along with that many researches have underlined the pivotal role of knowledge management for enterprise system success. This research in progress paper explores articles published in 8 journals during recent 11 years for knowledge management instances across ES lifecycle and categorizes these processes according to each phase of ES and knowledge management lifecycle. Subsequently presents the further analysis about gaps in the research area and under-studied fields which warrant future research.

Wang W.,University of Science and Technology Beijing | Hussin B.,University of Technology Malaysia | Jefferis T.,UK Defence Science and Technology Laboratory
International Journal of Production Economics | Year: 2012

This paper presents a case study of condition based maintenance modelling based on measured metal concentrations observed in oil samples of a fleet of marine diesel engines. The decision model for optimising the replacement time of the diesel engines conditional on observed measurements is derived and applied to the case discussed. We described the datasets, which were cleaned and re-organised according to the need of the research. The residual time distribution required in the decision model was formulated using a technique called stochastic filtering. Procedures for model parameter estimation are constructed and discussed in detail. The residual life model presented has been fitted to the case data, and the modelling outputs are discussed. © 2011 Elsevier B.V.

Ahmadi P.,University of Ontario Institute of Technology | Mohd Jaafar M.N.,University of Technology Malaysia
Applied Thermal Engineering | Year: 2014

In this research study, a combined cycle based on the Brayton power cycle and the ejector expansion refrigeration cycle is proposed. The proposed cycle can provide heating, cooling and power simultaneously. One of the benefits of such a system is to be driven by low temperature heat sources and using CO 2 as working fluid. In order to enhance the understanding of the current work, a comprehensive parametric study and exergy analysis are conducted to determine the effects of the thermodynamic parameters on the system performance and the exergy destruction rate in the components. The suggested cycle can save the energy around 46% in comparison with a system producing cooling, power and hot water separately. On the other hand, to optimize a system to meet the load requirement, the surface area of the heat exchangers is determined and optimized. The results of this section can be used when a compact system is also an objective function. Along with a comprehensive parametric study and exergy analysis, a complete optimization study is carried out using a multi-objective evolutionary based genetic algorithm considering two different objective functions, heat exchangers size (to be minimized) and exergy efficiency (to be maximized). The Pareto front of the optimization problem and a correlation between exergy efficiency and total heat exchangers length is presented in order to predict the trend of optimized points. The suggested system can be a promising combined system for buildings and outland regions. © 2013 Elsevier Ltd. All rights reserved.

Zahedi G.,University of Technology Malaysia | Lohi A.,Ryerson University | Mahdi K.A.,Kuwait University
Fuel Processing Technology | Year: 2011

In this research a dynamic grey box model (GBM) of ethylene oxide (EO) fixed bed reactor has been presented. In the first step of the study, kinetic model of the existing reactions was obtained using artificial neural network (ANN) approach. In order to build the ANN model industrial data of a typical EO reactor were employed. Time, C2H4, C2H 4O, CO2, H2O and O2 mole fractions were network inputs and the multiplication of reaction rate and catalyst deactivation (r* a)was ANN output. From 164 data, 109 data were employed to train ANN. After employing different training algorithms, it was found that, the radial basis function network (RBFN) training algorithm provides the best estimations of the data. This best obtained network was tested against fifty five unseen data. The network estimations were close to unseen data which confirmed generalization capability of the obtained network. In the next step of study, (r* a) was estimated with ANN and then the hybrid model of the reactor was solved. Simulation results were compared with EO mechanistic model and also with plant industrial data. It was found that GBM is 8.437 times more accurate than the mechanistic model. © 2011 Elsevier B.V.

Jeong J.,University of Technology Malaysia
Proceedings of the International Symposium on Consumer Electronics, ISCE | Year: 2011

This paper presents analysis of nonminimum phase component on acoustic transfer function as unknown system when adaptive FIR (finite impulse response) filter is used for noise cancelling scheme. For the application in realistic reverberant environment, nonminimum phase component is analyzed in beamforming structure. From the analysis, it has been found that it provides a consistency in estimate by adaptive FIR filter between direct and its inverted transfer functions. Based on this, by applying minimum phase filter in front, it will be shown that rear-end adaptive FIR filter is only related with nonminimum phase term due to absorption of minimum phase term by front-end minimum phase filter in beamforming structure. © 2011 IEEE.

Bahadori A.,Southern Cross University of Australia | Zahedi G.,University of Technology Malaysia | Zendehboudi S.,University of Waterloo
Renewable and Sustainable Energy Reviews | Year: 2013

Hydropower is the most advanced and mature renewable energy technology and provides some level of electricity generation in many countries worldwide. As hydropower does not consume or pollute the water it uses to generate power, it leaves this vital resource available for other uses. The objective of this article is to identify and analyse issues that are imperative for hydropower energy development in Australia. This study shows opportunities for further hydroelectricity generation in Australia are offered by refurbishment and efficiency improvements at existing hydroelectricity plants, and continued growth of small-scale hydroelectricity plants connected to the grid. © 2012 Elsevier Ltd.

Mohamad H.,University of Technology Malaysia | Soga K.,University of Cambridge | Amatya B.,Halcrow Group Ltd.
Geotechnical Testing Journal | Year: 2014

Recent advancement in distributed fiber-optic sensing offers new possibilities for performance monitoring in the field of geotechnical and civil engineering. Brillouin optical time-domain reflectometry (BOTDR) is a commercially available technology that allows distributed strain measurements in the microstrain range along the full length of an optical fiber. By integrating a single fiber-optic cable into soil or a structure, an unprecedented amount of reasonably accurate (±30με), spatially resolved data could be obtained. Since the BOTDR data is influenced by both strain and temperature, it is important that methods to separate the two effects are fully understood. This paper describes the BOTDR temperature compensation method by implementing appropriate thermal expansion coefficients of optical cables and structures to the raw data. In the laboratory study, validation of the instrumentation technique was conducted in a concrete beam by embedding two types of optical cables consisting of tight-buffered and loose-tubed coatings to measure thermal strains response during concrete curing. Temperature readings inferred from optical fibers were found to be in accordance to the thermocouples. A field study of axially loaded concrete pile subjected to cooling and heating cycle is presented. Measurements in the test pile and adjacent borehole indicate similar strain profiles and temperature changes between BOTDR and conventional instrumentation such as vibrating wire strain gauges and thermistors. General steps to derive the temperature compensated strain profiles observed in the thermal pile as a result of cooling and heating is presented. The data enables load-transfer profiles to be interpreted and used as framework to understand pile response to temperature changes. © 2014 by ASTM Int'l all rights reserved..

Tahmasebi M.M.,University of Technology Malaysia
Procedia Engineering | Year: 2011

Energy efficiency has become increasingly important to the community, regulatory bodies and industry in recent years. Dominant per capita energy consumption is associated with home used energy resources which also contribute to greenhouse gases. The main objective of this work is to evaluate the direct impacts of variations of multi-glazed windows on the sustainability through BIM software and determining the rate of energy consumption and carbon foot print in accordance with the implemented changes in a building. The altered parameters in this study are number of glazed layers, filled gases, sizes and orientations of the windows. The case study is a 56.25 m 2 hut which is built in one level and located in Kuala Lumpur. The simulation is carried out by using ArchiCad 14 software which is one of the pioneers in BIM and its new sustainability plug-in integrated into this software known as Grafosoft EcoDesigner. It is concluded that the type of gas used in double and triple glazed windows and increasing the size of windows to 41% of an area of the window to floor surface ratio do not differ significantly from 34% of area of window to floor surface ratio with regard to the energy consumption and carbon footprint in tropical areas. © 2011 Published by Elsevier Ltd.

Hadibarata T.,University of Technology Malaysia | Kristanti R.A.,Yamanashi University
Bioresource Technology | Year: 2012

Armillaria sp. F022, a white-rot fungus isolated from a tropical rain forest in Samarinda, Indonesia, was used to biodegrade benzo[. a]pyrene (B. aP). Transformation of B. aP, a 5-ring polycyclic aromatic hydrocarbon (PAH), by Armillaria sp. F022, which uses B. aP as a source of carbon and energy, was investigated. However, biodegradation of B. aP has been limited because of its bioavailability and toxicity. Five cosubstrates were selected as cometabolic carbon and energy sources. The results showed that Armillaria sp. F022 used B. aP with and without cosubstrates. A 2.5-fold increase in degradation efficiency was achieved after addition of glucose. Meanwhile, the use of glucose as a cosubstrate could significantly stimulate laccase production compared with other cosubstrates and not using any cosubstrate. The metabolic pathway was elucidated by identifying metabolites, conducting biotransformation studies, and monitoring enzyme activities in cell-free extracts. The degradation mechanism was determined through the identification of several metabolites: benzo[. a]pyrene-1,6-quinone, 1-hydroxy-2-benzoic acid, and benzoic acid. © 2011 Elsevier Ltd.

Fulazzaky M.A.,University of Technology Malaysia
Water (Switzerland) | Year: 2014

The increased demands for water and land in Indonesia as a consequence of the population growth and economic development has reportedly have been accelerated from the year to year. The spatial and temporal variability of human induced hydrological changes in a river basin could affect quality and quantity of water. The challenge is that integrated water resources management (IWRM) should cope with complex issues of water in order to maximize the resultant economic and social welfare in an equitable manner, without compromising the sustainability of vital ecosystems. Even though the government of Indonesia has adopted new paradigm for water resources management by the enactment of Law No. 7/2004 on water resources, the implementation of IWRM may face the technical and managerial challenges. This paper briefly reviews the implementation of IWRM and related principles and provides an overview of potential water-related issues and progress towards implementation of IWRM in Indonesia. The availability of water and a broader range of water-related issues are identified. The recommended actions for improving the future IWRM are suggested. Challenges to improve the capacity buildings of IWRM related to enabling environment, institutional frameworks and management instruments are verified to contribute to the future directions for efficient problem-solving ability. © 2014 by the author.

Yoo J.-H.,Hanyang University | Lee H.-S.,Hanyang University | Ismail M.A.,University of Technology Malaysia
Construction and Building Materials | Year: 2011

Because concrete is a type of porous material, water or air can permeate freely into the concrete and that decreases the durability of concrete. Therefore, it is possible to permeate some corrosion inhibitors from the surface of concrete to inside the concrete due to its porosity even the steel-frame location by applying water pressure. The objective of this study is to investigate the depth of the water penetration in concrete forced under pressure. For achieving this purpose, the experiments for the depth of penetration were executed through selecting related factors and levels, such as water pressure and water pressurizing time. The water flow in concrete was examined theoretically and experimentally. As a result, in the case of the low water pressure approximately at 0.15 MPa or less, it was found that the flow showed a Darcy seepage flow and the same flow as an ordinary sand stratum. However, in the case of the high water pressure, the flow was diffused as a seepage flow that is accompanied by an internal deformation of concrete. This study attempts to develop a method that penetrates corrosion inhibitors to the location of steel bars and investigate the penetration depth of corrosion inhibitors by verifying water penetration in concrete under applied pressure. © 2010 Elsevier Ltd. All rights reserved.

Salman B.H.,University of Tenaga Nasional | Mohammed H.A.,University of Technology Malaysia | Munisamy K.M.,University of Tenaga Nasional | Kherbeet A.Sh.,University of Tenaga Nasional
Renewable and Sustainable Energy Reviews | Year: 2013

Research on convective heat transfer on internal microtube and microchannel has been extensively conducted in the past decade. This review summarizes numerous researches on two topics; the first section focuses on studying the fluid flow and heat transfer behavior of different types of microtubes (MT) and microchannel (MC) at different orientations. The second section concentrates on nanofluids; its preparation, properties, behavior, and many others. The purpose of this article is to get a clear view and detailed summary of the influence of several parameters such as the geometrical specifications, boundary conditions, and type of fluids. The maximum Nusselt number is the main target of such research where correlation equations were developed in experimental and numerical studies are reported. The heat transfer enhancement of nanofluids along with the nanofluids preparation technique, types and shapes of nanoparticles, base fluids and additives, transport mechanisms, and stability of the suspension are also discussed. © 2013 Elsevier Ltd. All rights reserved.

Reza Dousti M.,University of Technology Malaysia | Reza Dousti M.,Islamic Azad University at Tehran
Journal of Applied Physics | Year: 2013

The effect of silver nanoparticles (NPs) on the optical properties of Nd3+-doped sodium-lead tellurite glass prepared by melting-quenching technique is investigated. The X-ray diffraction patterns confirm the amorphous nature of the samples. The average size of silver NPs increases from 7 to 18nm by addition of AgNO3 content. The surface plasmon resonance band of the silver NPs was recorded at 522nm for 0.5 mol. % AgNO3. Large upconversion enhancements (∼16 and 10 times) are attributed to the enlarged local field in vicinity of silver NPs. Feasible interactions between the excitation light and Nd3+:Ag NP co-doped tellurite glass are discussed. © 2013 AIP Publishing LLC.

Ben-Edigbe J.,University of Technology Malaysia
International Journal of Sustainable Development and Planning | Year: 2010

Many of the speed, flow and density relationships postulated in different literatures are based on empirical evidences collected under favourable conditions. Those that veered into comparative analysis under contrasting conditions often use forced curves to describe the relationship between speed and flow mainly because the graph is not a function. However, the paper is an attempt to postulate that dynamic speed-flow, speed-density and flow-density functions have similar behavioural pattern. In the study, speed and flow relationship under adverse road surface condition depicted with potholes and edge subsidence among others was investigated. The study was carried out in Nigeria where adverse road surface condition on principal roads is prevalent under daylight, dry weather and off-peak conditions. It is based on the hypothesis that adverse road surface condition has significant impact on otherwise uninterrupted traffic stream. The paper compared empirical survey data from 11 locations on roadway segments with control and adverse sections. Optimum speeds for control and adverse road sections were estimated and compared. The study found 50% reduction in optimum speed and concluded that significant speed reduction will occur under adverse road surface condition. © 2010 WIT Press.

Zaidel D.N.A.,Technical University of Denmark | Zaidel D.N.A.,University of Technology Malaysia | Chronakis I.S.,Technical University of Denmark | Meyer A.S.,Technical University of Denmark
Food Hydrocolloids | Year: 2013

Enzyme catalyzed oxidative cross-linking of feruloyl groups can promote gelation of sugar beet pectin (SBP). It is uncertain how the enzyme kinetics of this cross-linking reaction are affected in emulsion systems and whether the gelation affects emulsion stability. In this study, SBP (2.5% w/v) was mixed into an oil-in-water emulsion system (4.4% w/w oil, 0.22% w/w whey protein, pH 4.5). Two separate, identically composed, emulsion systems were prepared by different methods of preparation. The emulsions prepared separately and subsequently mixed with SBP (referred as Mix A) produced significantly larger average particle sizes than the emulsions in which the SBP was homogenized into the emulsion system during emulsion preparation (referred as Mix B). Mix B type emulsions were stable. Enzyme catalyzed oxidative gelation of SBP helped stabilize the emulsions in Mix A. The kinetics of the enzyme catalyzed oxidative gelation of SBP was evaluated by small angle oscillatory measurements for horseradish peroxidase (HRP) (EC and laccase (EC catalysis, respectively. HRP catalyzed gelation rates, determined from the slopes of the increase of elastic modulus (G') with time, were higher (P < 0.05) than the corresponding laccase catalyzed rates, but the final G' values were higher for laccase catalyzed gels, regardless of the presence of emulsions or type of emulsion preparation (Mix A or Mix B). For both enzymes, rates of gelation in Mix A were higher (P < 0.05) than in Mix B, and higher stress was needed to break the gels in Mix A than in Mix B at similar enzyme dosage levels. These differences may be related to a lower availability of the feruloyl groups for cross-linking when the SBP was homogenized into the emulsion system during preparation. © 2012 Elsevier Ltd.

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.

Othman I.K.,University of Queensland | Othman I.K.,University of Technology Malaysia | Baldock T.E.,University of Queensland | Callaghan D.P.,University of Queensland
Coastal Engineering | Year: 2014

The paper examines the dependency between total sediment transport, q, and grain size, D (i.e. q∝Dp) under dam break generated swash flows. Experiments were performed in a dam break flume over a sloping mobile sand bed with median grain sizes ranging from 0.22mm to 2.65mm. The total sediment transport was measured by truncating the flume bed and collecting the sediment transported over the edge. The experiments were designed to exclude pre-generated turbulence and pre-suspended sediment so as to focus solely on the swash flow. The magnitude and nature of the grain size dependency (i.e. p value) were inferred for different flow parameters; the initial dam depth, do, the integrated depth averaged velocity cubed, ∫u3dt, and against the predicted transport potential, qp, using the Meyer-Peter Muller (MPM) transport model and variations of that model. The data show that negative dependencies (p<0) are obtained for do and qp, whilst positive dependencies (p>0) are obtained for ∫u3dt. This indicates that a given do and qp transport less sediment as grain size increases, whereas transport increases with grain size for a given ∫u3dt. The p value is found to be narrowly ranged, 0.5≤p≤-0.5. On average, the incorporation of a pressure gradient term via the piezometric head into the MPM formulation reduces qp by 4% (fine sand) to 18% (coarse sand). The measured total transport for fine and coarse sands is best predicted using MPM and MPM+ dp*/dx respectively. However, the inferred optimum transport coefficient in the MPM formulation is about 30, much higher than the standard coefficient in a steady flow and this is not due to the presence of the pre-suspended sediment. The optimum transport coefficient indicates some sensitivity to grain size, suggesting that some transport processes remain unaccounted for in the model. © 2013 Elsevier B.V.

Ahmed A.A.,Taiz University | Fisal N.F.,University of Technology Malaysia
Security and Communication Networks | Year: 2011

Wireless sensor network (WSN) is a wireless ad hocnetwork that consists of a very large number of tiny sensor nodes communicating with each other with limited power and memory constrain. WSN demands real-time forwarding which means messages in the network are delivered according to their end-to-end deadlines (packet lifetime). Since many sensor networks will be deployed in critical applications, security is essential. Recently, many real-time routing protocols have been proposed, but none is designed with security. This paper proposes a novel secure real-time with load distribution (SRTLD) routing protocol that provides secure real-time data transfer and efficient distributed energy usage in WSN. The SRTLD routing protocol ensures high packet throughput and minimized packet overhead. It has been successfully studied and verified through simulation and real test bed implementation. © 2010 John Wiley & Sons, Ltd.

Haidar A.M.A.,Universiti Malaysia Pahang | Mustafa M.W.,University of Technology Malaysia | Ibrahim F.A.F.,Taiz University | Ahmed I.A.,Hodeidah University
Applied Soft Computing Journal | Year: 2011

Transient stability evaluation (TSE) is part of dynamic security assessment of power systems, which involves the evaluation of the system's ability to remain in equilibrium under credible contingencies. Neural networks (NN) have been applied to the security assessment of power systems and have shown great potential for predicting the security of power systems. This paper proposes a generalized regression neural networks (GRNN) based classification for transient stability evaluation in power systems. In the proposed method, learning data sets have been generated using time domain simulation (TDS). The GRNN input nodes representing the voltage magnitude for all buses, real and reactive powers on transmission lines, the output node representing the transient stability index. The proposed GRNN was implemented and tested on IEEE 9-bus and 39-bus test systems. NN results show that the stability condition of the power system can be predicted with high accuracy and less misclassification rate. © 2011 Elsevier B.V.

Sharer Z.,University of Oxford | Sharer Z.,University of Technology Malaysia | Sykes J.,University of Oxford
Progress in Organic Coatings | Year: 2012

The proposition that corrosion rate is limited by the ionic resistance of an organic coating has been tested. Mild steel panels coated with an epoxy-phenolic paint were exposed to 3% sodium chloride solution at 50 °C for different periods and characterized by electrochemical impedance spectroscopy (EIS) across a range of temperatures (25-50°C). Changes in the film resistance and charge-transfer resistance with temperature were analysed to deduce activation energies for the processes involved. It was found that the calculated activation energy from coating resistance is significantly lower than the activation energy for the charge transfer resistance. This suggests that the ionic resistance of the coating, as apparent in an AC measurement, cannot be controlling the corrosion rate. Coating resistances for free films of the same coating show even higher activation energy values, so that the resistance of un-degraded areas of the coating within the current path could be controlling the current flow. Potentiostatic pulse tests on coated metal have enabled iR-corrected polarization curves to be plotted at different temperatures that gave high activation energies from the estimated corrosion currents. This provides two possible explanations that can account for the results. © 2012 Elsevier B.V. All rights reserved.

Kherbeet A.S.,University of Tenaga Nasional | Mohammed H.A.,University of Technology Malaysia | Munisamy K.M.,University of Tenaga Nasional | Salman B.H.,University of Tenaga Nasional
International Journal of Heat and Mass Transfer | Year: 2014

Simulation of laminar mixed convective flow over a 3-D horizontal microscale backward-Facing step (MBFS) is presented to explore the effect of step height on the flow and heat transfer characteristics. The momentum and energy equations were discretized by means of a finite volume method (FVM). The SIMPLE algorithm scheme was used to link the pressure and velocity fields in the entire domain. Three values of step height were considered S = 350 μm, S = 450 μm and S = 550 μm. EG-SiO2 nanofluid was considered as the working fluid with 25 nm nanoparticle diameter, 0.04 volume fraction. The results revealed that the Nusselt number and skin friction coefficient increase with the increase of the step height. The Reynolds number and pressure drop were found to decrease with the increase of the step height. © 2013 Elsevier Ltd. All rights reserved.

Ahmad Z.,University of Technology Malaysia | Thambiratnam D.P.,Queensland University of Technology | Tan A.C.C.,Queensland University of Technology
International Journal of Impact Engineering | Year: 2010

This paper treats the crush behaviour and energy absorption response of foam-filled conical tubes subjected to oblique impact loading. Dynamic computer simulation techniques validated by experimental testing are used to carry out a parametric study of such devices. The study aims at quantifying the energy absorption of empty and foam-filled conical tubes under oblique impact loading, for variations in the load angle and geometry parameters of the tube. It is evident that foam-filled conical tubes are preferable as impact energy absorbers due to their ability to withstand oblique impact loads as effectively as axial impact loads. Furthermore, it is found that the energy absorption capacity of filled tubes is better maintained compared to that of empty tubes as the load orientation increases. The primary outcome of this study is design information for the use of foam-filled conical tubes as energy absorbers where oblique impact loading is expected. © 2009 Elsevier Ltd. All rights reserved.

Chong C.T.,University of Technology Malaysia | Hochgreb S.,University of Cambridge
Fuel | Year: 2014

The spray combustion characteristics of rapeseed methyl esters (RME) were compared to Jet-A1 fuel using a gas turbine type combustor. The swirling spray flames for both fuels were established at a constant power output of 6 kW. The main swirling air flow was preheated to 350 C prior to coaxially enveloping the airblast-atomized liquid fuel spray at atmospheric pressure. Investigation of the fundamental spray combustion was performed via measurements of the fuel droplet sizes and velocities, gas phase flow fields and flame reaction zones. The spray flame droplets and flow fields in the combustors were characterised using phase Doppler anemometry (PDA) and particle imaging velocimetry (PIV) respectively. Flame chemiluminescence imaging was employed to identify the flame reaction zones. The highest droplet concentration zone extends along a 30 angle from the symmetry axis, inside the flame zone. Only small droplets(<17 μ) (<17 μm)are found around the centreline region, while larger droplets are found at the edge of the spray outside the flame reaction zone. RME exhibits spray characteristics similar to Jet-A1 but with droplet concentration and volume fluxes four times higher, consistent with the expected longer droplet evaporation timescale. The flow field characteristics for both RME and Jet-A1 spray flames are very similar despite the significantly different visible characteristics of the flame reaction zones. © 2013 Elsevier Ltd. All rights reserved.

Abdel-Akher M.,South Valley University | Nor K.M.,University of Technology Malaysia
IEEE Transactions on Power Delivery | Year: 2010

The paper presents a new approach for performing the fault analysis of multiphase distribution networks based on the symmetrical components. The multiphase distribution system is represented by an equivalent three-phase system; hence, the single-phase and two-phase line segments are represented in terms of their sequence values. The proposed technique allows the state of the art short-circuit analysis solvers to analyze unbalanced distribution networks. The fault currents calculated using the proposed technique is compared with the phase components short-circuit analysis solver. The obtained results for the IEEE radial test feeders show that the proposed technique is accurate. Based on the proposed method, the existing commercial grade short-circuit analysis solvers based on sequence networks can be utilized for performing unbalanced distribution systems. © 2010 IEEE.

Soltanian M.R.K.,University of Malaya | Amiri I.S.,University of Malaya | Alavi S.E.,University of Technology Malaysia | Ahmad H.,University of Malaya
Laser Physics Letters | Year: 2015

The novel technique for generating the robust, ultra-wideband (UWB) signal in the optical domain using a mode-locked laser incorporated with an add-drop microring resonator filter is presented. In order to enable the down conversion of the UWB signal to the RF domain, two wavelength ranges 1553.72 and 1553.92 nm, which are 24.65 GHz apart from each other, are used. These wavelengths were generated based on a single longitudinal mode (SLM) dual-wavelength fiber laser in a laser ring cavity. The upper wavelength of the generated dual-wavelength laser is modulated with the UWB spectrum using an optical carrier suppression (OCS) scheme and the lower wavelength is kept unmodulated. After beating the modulated and unmodulated wavelength by launching into the photodiode, the 24 GHz UWB signal can be generated to be applied to UWB over fiber (UWBoF) technology. The error vector magnitude (EVM) for the signal transmission was calculated and the EVM below 10% is achieved for 25 Km optical and 20 m wireless links. © 2015 Astro Ltd.

Othman S.H.,University of Technology Malaysia | Othman S.H.,University of Wollongong | Beydoun G.,University of Wollongong
Information and Management | Year: 2013

Disaster management (DM) is a challenging domain to model because of the variety of dynamic characteristics attached to the domain. Metamodeling is a model-driven approach that describes how semantic domain models can be built into an artifact called a Metamodel. By collecting all the domain concepts and partitioning the domain problems into sub-domain-problems, a metamodel can produce a domain-specific language. This paper presents a Disaster Management Metamodel that can serve as a representational layer of DM expertise. This metamodel leads to better knowledge sharing and facilitates combining and matching different DM activities to best manage the disaster on hand. © 2013 Elsevier B.V.

Anwari M.,University of Technology Malaysia | Hiendro A.,University of Tanjungpura
IEEE Transactions on Energy Conversion | Year: 2010

This paper evaluates the influence of the unbalance factors in calculating total copper losses, efficiency, power factor, input power, output torque, peak currents, and derating factor of the motor operating under unbalanced voltage system. The complete definition for the voltage unbalance is using complex voltage-unbalance factor that consists of its magnitude and angle. A coefficient to determine either under- or overunbalance conditions is inserted. The analysis of the motor is performed using the method of symmetrical component, and MATLAB software is used to investigate the performance of the induction motor. The simulation results show that the International Electrotechnical Commission definition of the voltage unbalance combined with the coefficient of unbalance condition can be applied to evaluate total copper losses, input power, power factor, and total output torque precisely. However, the phase angle of the unbalance factor must be included for accurate prediction of peak current and peak copper losses of the phase windings and derating factor of the motor. © 2006 IEEE.

Soltanian M.R.K.,University of Malaya | Sadegh Amiri I.,University of Malaya | Alavi S.E.,University of Technology Malaysia | Ahmad H.,University of Malaya
Journal of Lightwave Technology | Year: 2015

We demonstrate a widely tunable dual-wavelength erbium-doped fiber laser that used a 10-cm photonic crystal fiber as a Mach-Zehnder interferometer to filter out the switchable dual-wavelength signals so as to generate tunable continuous-wave (CW) terahertz (THz) radiation. Each single longitudinal mode wavelength could be independently tuned by using a tunable band-pass filter and polarization controller (PC). The wavelength fine-tuning was achieved via adjustments to the PC, and the resulting dual-wavelength output had a side-mode suppression ratio (SMSR) of more than 30 dB. The wavelength spacing of 7, 11.4, and 21.2 nm, corresponding to 0.9, 1.4, and 2.66 THz radiation, respectively, was tuned in order to obtain CW THz radiation. This CW THz radiation was produced by means of a stable dual-wavelength fiber laser performing as the optical beat source, together with a DAST crystal-based photomixer. High-sensitivity thermal sensors calibrated for THz radiation were able to continuously detect the emitted CW THz radiation. © 1983-2012 IEEE.

Mustapha K.B.,University of Technology Malaysia
Computers, Materials and Continua | Year: 2014

This study investigates the sensitivity of the flexural response of a ribconnected system of coupled micro-panels with traction-free surfaces. Idealized as a two-dimensional elastic continuum with a finite transverse stiffness, each micropanels' behavior is examined within the framework of the biharmonic mathematical model derived from the higher-order, size-dependent strain energy formulation. The model incorporates the material length scale, which bears an associative relationship with the underlying polymer's averaged Frank elastic constant. Upper estimates of the eigenvalue of the system, under fully clamped edges and simplysupported edges, are determined by the Rayleigh method. The adopted theory for the micro-panel's behavior takes into account the rotary inertia, the small-scale effect, the Poisson's ratio and the effective stiffness of the ribs, but neglects shear distortion. Frequency shifts of the rib-connected coupled micro-panels are systematically identified and presented. Results indicate the critical thickness for which the polymeric micro-panel's resonant frequency starts to experience stiffened responses based on the magnitude of the size-effect. The Rayleigh method of eigenvalue extraction is augmented with the applied statistical method of design of experiment for the discovery of notable interaction effects between the aspect ratio, rotary inertia, small-scale effect, and thickness-to-span ratio of the system. Copyright © 2014 Tech Science Press.

Ng S.-M.,University of Technology Malaysia | Narayanaswamy R.,University of Manchester
Microchimica Acta | Year: 2010

This paper describes a simple, economical and practical optical sensor that has been developed using an ion imprinted polymer for detecting copper(II) ion using reflectance spectrometry. The imprinted polymer was synthesised in the presence of copper(II) ion using 4-vinylpyridine as monomer, 2-hydroxyethyl methacrylate as co-monomer, and ethylene glycol dimethacrylate as cross-linker in methanol via free radical polymerisation. The polymer formed was physically ground into fine particles, fabricated into a sensor probe and attached at the tip of an optical fibre bundle. The sensor operates optimally at pH 5 under constant stirring condition and has a linear dynamic range for copper(II) ion determination of 0.4-4.0 mM. The limit of detection for the sensor was 123 μM. The sensor has high selectivity for monitoring copper (II) ion in a multi-analyte environment, while also exhibiting better sensitivity compared to non-imprinted polymer. The response of the sensor can be regenerated fully without significant loss in its analytical signal for re-use. This reduces the consumable cost and at the same time making the operational process of such sensor simpler and more practical to be employed in real applications. © Springer-Verlag 2010.

Alexandrov S.,Russian Academy of Sciences | Mustafa Y.,University of Technology Malaysia
Meccanica | Year: 2013

The paper deals with asymptotic behavior of viscoplastic solutions in the vicinity of maximum friction surfaces under plane strain conditions. The definition of maximum friction surfaces is that the friction stress is equal to the shear yield stress at sliding. The constitutive equations of the viscoplastic model adopted include a saturation stress. It is shown that it is possible to choose parameters of the viscoplastic model such that the regime of sliding is possible at maximum friction surfaces. In this case solutions are singular in the vicinity of such surfaces. Because of this feature of solutions, the viscoplastic model chosen possesses a smooth transition of qualitative behavior between rigid perfectly plastic and viscoplastic solutions, and this may prove to be advantageous for some applications. © 2013 Springer Science+Business Media Dordrecht.

Prawoto Y.,University of Technology Malaysia
International Journal of Solids and Structures | Year: 2012

This is a short technical paper on how to use classical continuum and fracture mechanics to calculate the plastic zones caused by cracks on heterogeneous or composite materials. As an example, a sample consisting of an α-phase and β-phase is used. A crack is introduced to the sample, and stress is then applied. The plastic zone in front of the crack resulting from the applied stress is then calculated using commercial software. The concept uses two-level modeling: a global model using homogenized stiffness from a unit cell of heterogeneous material and a local model for the α-phase and β-phase. While this paper is written for general purposes, a concrete example using ferrite and martensite is also presented along with the experimental data. General agreement between the model and the experiment is observed. This method eliminates the need for a cumbersome analytical approach. © 2012 Elsevier Ltd. All rights reserved.

Rajoo S.,University of Technology Malaysia | Romagnoli A.,Imperial College London | Martinez-Botas R.F.,Imperial College London
Energy | Year: 2012

This paper discusses the details of unsteady experimentation and analysis of a twin-entry variable geometry turbine for an automotive turbocharger. The turbine in this study is the product of design progression from a commercial nozzleless unit to a single-entry variable geometry and consequently to a twin-entry unit. The main features of the turbine were kept similar across all configurations for equivalent comparison basis. The unsteady curves of the twin-entry turbine exhibited the conventional looping characteristics representing filling and emptying effects, which was also the case for the nozzleless and single-entry nozzled turbine. The swallowing capacity of the twin-entry turbine, during full admission testing, was recorded to be inconsistent between the two entries, in particular they were at different pressure ratio levels - the shroud end entry was in most cases more pressurized compared to the hub end entry, as much as 13%. Contrarily, during out-of-phase testing the swallowing capacity of both the turbine entries was found to be similar. The cycle-averaged efficiency of the nozzled turbine either twin or single-entry was found to depart significantly from the equivalent quasi-steady, in comparison to the nozzleless single-entry turbine, this was as much as 32%. © 2011 Elsevier Ltd.

Othman M.H.D.,Imperial College London | Othman M.H.D.,University of Technology Malaysia | Droushiotis N.,Imperial College London | Wu Z.,Imperial College London | And 2 more authors.
Journal of Power Sources | Year: 2012

In this study, a high performance micro-tubular solid oxide fuel cell (SOFC) has been developed by depositing a multi-layer cathode onto an improved electrolyte/anode dual-layer hollow fibre fabricated via a single-step co-extrusion/co-sintering technique. The use of 0-20 wt.% of ethanol in the inner layer spinning suspension allows the control over the asymmetric structure of the Ni-CGO anode layer, i.e. finger-like voids structure covering about 50-85% of the anode layer thickness with the rest volume occupied by sponge-like structure, and at the same time affects the morphology of the CGO electrolyte layer. The presence of finger-like voids significantly facilitates the fuel gas diffusion inside the anode, and as a result, the maximum power density increases from 1.84 W m -2 to 2.32 W cm -2, when the finger-like voids is increased from 50% to 70% of the asymmetric anode layer. However, further growth of finger-like voids, i.e. 85% of the anode layer, dramatically reduce the number of triple-phase boundary (TPB) region and conductivity in the anode, as well as the gas-tightness property of the electrolyte, which consequently decreases the maximum power density to 0.99 W cm -2. Based on the results obtained, therefore, dual-layer hollow fibres with 50-70% of finger-like voids in the anode layer can be considered as the ideal structure for producing high performance micro-tubular SOFCs. © 2012 Elsevier B.V. All rights reserved.

Djauhari M.A.,University Putra Malaysia | Gan S.L.,University of Technology Malaysia
Physica A: Statistical Mechanics and its Applications | Year: 2015

Since its introduction fifteen years ago, minimal spanning tree has become an indispensible tool in econophysics. It is to filter the important economic information contained in a complex system of financial markets' commodities. Here we show that, in general, that tool is not optimal in terms of topological properties. Consequently, the economic interpretation of the filtered information might be misleading. To overcome that non-optimality problem, a set of criteria and a selection procedure of an optimal minimal spanning tree will be developed. By using New York Stock Exchange data, the advantages of the proposed method will be illustrated in terms of the power-law of degree distribution. © 2014 Elsevier B.V. All rights reserved.

Aziz M.W.,University of Technology Malaysia
International Journal of Smart Home | Year: 2013

The successful implementations of the concepts of Service-Oriented Computing (SOC) in smart home in the recent years and the advantages it provide in the smart home development have proved its importance. However, efforts are still needed for service-oriented design of smart home, especially at the architectural level. Although a number of layered architectures are proposed for smart home in the past, most of them are related to middleware or hardware architecture design or explain the implementation details. A three-layered service-oriented architecture for smart home is proposed in this paper. On the one hand, the proposed architecture provides the facility to model the smart home in terms of devices and the services they provide, while on the other it provides the mean of communication to heterogeneous devices present in a smart home. To show the effectiveness of the proposed architecture, it was applied on "Food cooking and ordering" scenario in a smart home. The results showed that the proposed architecture helped in the increased understandability of the smart home design. © 2013 SERSC.

Chu B.-S.,Nestle | Chu B.-S.,University of Technology Malaysia | Nagy K.,Nestle
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2013

Quantification of monoacylglycerols (MAG) and free fatty acids (FA) is of interest in biological systems, in food, cosmetic and pharmaceutical products. This manuscript describes and validates a reversed phase liquid chromatography-tandem mass spectrometry based approach for simultaneous quantification of these analytes in fats and oils. Purification and concentration of MAG/FA were performed using cation exchange solid phase extraction, which allowed elimination of the abundant triacylglycerols. Following cleanup and concentration, the analytes were separated and detected with the aid of volatile ammonium-formate buffer. MAG were detected in positive ion mode, while FA were detected in negative ion mode. The method was validated by the method of standard additions and using stable isotope labeled internal standards. The results confirm the feasibility of quantifying these two classes of analytes simultaneously without any chemical derivatization. The obtained main quantitative features include: (1) lower limits of quantification 1-30. ppm for MAG analytes, (2) lower limits of quantification 90-300. ppm for FA analytes, (3) averaged inter-batch precision 6%, and (4) averaged bias -0.2% for MAG and 0.5% for FA. Various animal fat and vegetable oil samples were characterized for their MAG/FA profile indicating the usefulness of the method to address quality and authenticity of fats and oils. © 2013 Elsevier B.V.

Ahmed A.A.,King Abdulaziz University | Fisal N.,University of Technology Malaysia
International Journal of Sensor Networks | Year: 2014

Mobile wireless sensor network (MWSN) is a wireless ad hoc network that consists of a very large number of tiny sensor nodes communicating with each other in which sensor nodes are either equipped with motors for active mobility or attached to mobile objects for passive mobility. A real-time routing protocol for MWSN is an exciting area of research because messages are delivered according to their end-to-end deadlines. MWSN demands real-time routing in many applications including disasters fighting, forest fire detection and volcanic eruption detection. This paper proposes a novel idea of real-time that provides mobility and load distribution (RTMLD) for MWSN. RTMLD utilised corona mechanism and optimal forwarding metrics to forward the data packet in MWSN. It computes the optimal forwarding node based on RSSI, remaining battery level of sensor nodes and packet delay over one-hop. RTMLD ensures high packet delivery ratio and experiences minimum end-to-end delay in WSN and MWSN compared with baseline routing protocol. RTMLD has been successfully verified through test bed and simulation experiment. Copyright © 2014 Inderscience Enterprises Ltd.

Djauhari M.A.,University of Technology Malaysia
Physica A: Statistical Mechanics and its Applications | Year: 2012

We show that the use of a minimal spanning tree (MST) to filter important information in a complex system is not robust except when the system contains a unique MST. In this paper we propose to use the forest of all MSTs as a robust filter. According to this filter, centrality measures are also robust. For that purpose an algorithm, which can also be used to detect the uniqueness of an MST, will be provided. A simple hypothetical example will clarify the construction of the proposed filter and a real problem in filtering the information contained in NYSE 100 stocks will illustrate its advantages compared to the MST-based filter. © 2012 Elsevier B.V. All rights reserved.

Chua L.S.,University of Technology Malaysia
Journal of Ethnopharmacology | Year: 2013

Ethnopharmacological relevance Rutin is a common dietary flavonoid that is widely consumed from plant-derived beverages and foods as traditional and folkloric medicine worldwide. Rutin is believed to exhibit significant pharmacological activities, including anti-oxidation, anti-inflammation, anti-diabetic, anti-adipogenic, neuroprotective and hormone therapy. Till date, over 130 registered therapeutic medicinal preparations are containing rutin in their formulations. This article aims to critically review the extraction methods for plant-based rutin and its pharmacological activities. This review provides comprehensive data on the performance of rutin extraction methods and the extent of its pharmacological activities using various in vitro and in vivo experimental models. Materials and methods Literatures including journals, patents, books and leaflets reporting on rutin from natural resources are systematically reviewed, particularly in the aspect of its extraction methods and biological activities. Factors affecting the efficiency of rutin extraction such as extraction temperature, duration and solvent to sample ratio are presented based on the findings of previous studies. The observed biological activities followed by clear explanation are also provided accordingly. Results The biological activities of rutin varied largely dependent on the geographical and plant origins. The complexity of natural rutin has impeded the development of rutin derived drugs. The detail mechanism of rutin in human body after consumption is still unclear. Therefore, studies are intensively carried out both in vitro and in vivo for the better understanding of the underlying mechanism. The studies are not limited to the pharmacological properties, but also on the extraction methods of rutin. Many studies have focused on the optimization of extraction method to increase the extraction yield of rutin. Currently, the performances of modern extraction approaches have also been compared to the conventional heat reflux method as a benchmark. Conclusion There are various extraction methods for plant-based rutin ranging from conventional method up to the use of modern techniques such as ultrasound, mechanochemical, microwave, infrared and pressurized assisted methods. However, proper comparison between the methods is very difficult because of the variance in plant origin and extraction conditions. It is important to optimize the extraction method in order to produce high yield and acceptable purity of rutin with a reasonable cost. Even though rutin has been proven to be effective in numerous pharmacological activities, the dosage and toxicity of rutin for such activities are still unknown. Future research should relate the dosage and toxicity of rutin for the ethnobotanical claims based on the underlying mechanisms. © 2013 Elsevier Ireland Ltd.

Kama N.,University of Technology Malaysia
International Journal of Software Engineering and its Applications | Year: 2013

Impact analysis predicts the parts of the software system that can be affected by changes in the system. Selecting the approach to perform impact analysis in the software development phase requires consideration of the class artifact status. Static analysis approaches do not require class artifacts to be fully developed. However, the analysis tends to overestimate the number of affected classes. So it is of little practical use. On the other hand, dynamic analysis approaches expect all the class artifacts to be fully developed. So the analysis tends to be imprecise when not all class artifacts are fully developed. This paper reviews current impact analysis techniques' capability from the perspective of supporting the software development phase implementation. Based on this review, the needs of a new impact analysis technique for the software development phase are then constructed.

Mirzal A.,University of Technology Malaysia
Proceedings - 2013 IEEE International Conference on Control System, Computing and Engineering, ICCSCE 2013 | Year: 2013

Latent semantic indexing (LSI) is an indexing method to improve performance of an information retrieval system by indexing terms that appear in related documents and weakening influences of terms that appear in unrelated documents. LSI usually is conducted by using the truncated singular value decomposition (SVD). The main difficulty in using this technique is its retrieval performance depends strongly on the choosing of an appropriate decomposition rank. In this paper, by observing the fact that the truncated SVD makes the related documents more connected, we devise a matrix completion algorithm that can mimick this capability. The proposed algorithm is nonparametric, has convergence guarantee, and produces a unique solution for each input. Thus it is more practical and easier to use than the truncated SVD. Experimental results using four standard datasets in LSI research show that the retrieval performances of the proposed algorithm are comparable to the best results offered by the truncated SVD over some decomposition ranks. © 2013 IEEE.

Kazemilari M.,University of Technology Malaysia | Djauhari M.A.,University Putra Malaysia
Physica A: Statistical Mechanics and its Applications | Year: 2015

This paper shows how the concept of vector correlation can appropriately measure the similarity among multivariate time series in stocks network. The motivation of this paper is (i) to apply the RV coefficient to define the network among stocks where each of them is represented by a multivariate time series; (ii) to analyze that network in terms of topological structure of the stocks of all minimum spanning trees, and (iii) to compare the network topology between univariate correlation based on r and multivariate correlation network based on RV coefficient. ©2015 Elsevier B.V. All rights reserved.

Mohamed Ali M.S.,University of British Columbia | Mohamed Ali M.S.,University of Technology Malaysia | Takahata K.,University of British Columbia
Journal of Micromechanics and Microengineering | Year: 2011

This paper reports wireless microfluidic control enabled by the selective operation of multiple bulk-micromachined shape-memory-alloy actuators using external radiofrequency magnetic fields. Each shape-memory-alloy actuator is driven by a wireless resonant heater which generates heat only when the field frequency is tuned to the resonant frequency of the heater. Multiple actuators coupled with the heater circuits that are designed to have different resonant frequencies in the range of 135-295 MHz are selectively and simultaneously controlled by modulating the field frequency to the resonant frequencies of the corresponding heaters. A wireless microsyringe device that has three actuator-heater components and a flexible parylene reservoir is developed. The 5 μl reservoir is squeezed by the 5 mm long cantilever-type actuators to eject controlled amount of liquid from the reservoir. Using the device with an acidic solution loaded in the reservoir, sequential modifications of the pH level in the liquid are experimentally demonstrated through the selective control of the three actuators. The thermal characterization of the actuator using infrared imaging shows a temperature increase of 50 °C in 4 s and the full activation of the actuator in 8 s with 300 mW field output power. © 2011 IOP Publishing Ltd.

Abdul-Aziz A.,University of Technology Malaysia | Wong F.-L.,Biologics
Engineering in Life Sciences | Year: 2011

A permselective membrane fabricated from photo-cross-linked poly(hydroxyethyl methacrylate) (pHEMA) was studied as a potential selective membrane that can eliminate electrochemical interferences commonly faced by a hydrogen peroxide-based biosensor. The quantitative selection of the permselective membrane was based on the permeabilities of hydrogen peroxide and acetaminophen (AC). AC was used as a model of the interfering substance due to its neutral nature. pHEMA membrane with the cross-linking ratio of 0.043 was found to achieve a selectivity of hydrogen peroxide over AC of 10, while maintaining an acceptable degree of hydrogen peroxide response. A two-layer glucose biosensor model consisting of glucose oxidase entrapped within a freeze-thawed poly(vinyl alcohol) matrix and the cross-linked pHEMA membrane was challenged with AC, ascorbic acid and uric acid. 0.2mM AC and 0.2mM ascorbic acid were completely eliminated. However, 0.2mM uric acid could not be completely eliminated and still gave a bias of approximately 6.6% relative to 5mM glucose. The results showed that cross-linked pHEMA was quite promising as an interference eliminating inner membrane. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rehman A.,Islamic University | Saba T.,University of Technology Malaysia
Artificial Intelligence Review | Year: 2014

Neural network are most popular in the research community due to its generalization abilities. Additionally, it has been successfully implemented in biometrics, features selection, object tracking, document image preprocessing and classification. This paper specifically, clusters, summarize, interpret and evaluate neural networks in document Image preprocessing. The importance of the learning algorithms in neural networks training and testing for preprocessing is also highlighted. Finally, a critical analysis on the reviewed approaches and the future research guidelines in the field are suggested. © 2012 Springer Science+Business Media B.V.

Rezaei S.,University of Technology Malaysia | Ghodsi S.S.,Multimedia University
Computers in Human Behavior | Year: 2014

A few study examined the impact of value and aspects of behavioral intention in virtual environment. The aim of this study is to examine the impact of emotional value (VE), social value (VS), price-value for money (VP), performance-quality value (VQ) and repurchase intention (RI), willingness to pay a premium price (WTP) and word of mouth (WOM) among massively multiplayer online role-playing games (MMORPGs). A total of 228 valid questionnaires were collected from cybercafé customers in Klang Valley-Malaysia. Structural equation modeling (SEM) was employed using partial least squares (PLS) analysis to assess measurement and structural model for reflective construct. Our result reveals that there is a positive relationship between VP and RI, VQ and RI while there is no positive relationship between VE and RI, VS and RI. VE, VP and VQ value positively impact WOM but VS does not. VE and VP have positive while VQ and VS did not explain WTP. This study contributes to literature on the new phenomena of online game and is considered as few studies in examining value in Second Life setting. The practical and social implications of study are discussed along with research limitation and implication. © 2014 Elsevier Ltd. All rights reserved.

Hadibarata T.,University of Technology Malaysia
Journal of Biological Sciences | Year: 2013

The aim of this study is to evaluate amaranth textile dye decolorization by white-rot fungus Pleurotus eryngiF019 isolated from tropical rain forest. The isolate was able to decolorize an azo dye in wide range (up to 200 mg), at temperature 25°C. The results revealed that the removal azo dye amaranth was rapid at the initial incubation period (15 days) and became slowly with the time (30 days). The maximum decolorization was observed after 30 days incubation. Addition of Cu2+, Mg2+, Mn2+ gave the positive results while decolorization was inhibited by addition of Fe2+. Metal ion also affected the level of enzyme production during decolorization of amaranth. Induction in the activity of laccase and lignin peroxidase was observed during decolorization of amaranth in the culture, which represented their important role in biotransformation. The biodegradation of amaranth dye was monitored by UV-Vis spectrometer and gas chromatography. These promising results suggest the application of Pleurotus eryngi F019 to treat dye containing wastewater having higher concentrations of metals. © 2013 Asian Network for Scientific Information.

Yorino N.,Hiroshima University | Hafiz H.M.,University of Technology Malaysia | Hafiz H.M.,Hiroshima University | Sasaki Y.,Hiroshima University | Zoka Y.,Hiroshima University
IEEE Transactions on Power Systems | Year: 2012

A large amount of renewable energy penetration may cause a serious problem in load dispatch in the future power system, where the amount of controllable generators will decrease while disturbances increase. Therefore, a new economic load dispatch (ELD) method is required in order to make the best use of the ramp-rate capability of existing generators to cope with the disturbances caused by loads as well as by renewable energy generations. This paper proposes a new dynamic ELD method to meet the general requirements for real-time use in a future power system, where load following capability is critically limited. The method is also satisfactory from an economical point of view, and is suitable for high-speed online application due to fast and steady computation time. The proposed method has been successfully tested on several systems supplying a typical morning to noon demand profile. © 2012 IEEE.

Kurniawati E.,Gadjah Mada University | Rohman A.,Gadjah Mada University | Rohman A.,University of Technology Malaysia | Triyana K.,Gadjah Mada University
Meat Science | Year: 2014

Meatball is one of the favorite foods in Indonesia. For the economic reason (due to the price difference), the substitution of beef meat with pork can occur. In this study, FTIR spectroscopy in combination with chemometrics of partial least square (PLS) and principal component analysis (PCA) was used for analysis of pork fat (lard) in meatball broth. Lard in meatball broth was quantitatively determined at wavenumber region of 1018-1284cm-1. The coefficient of determination (R2) and root mean square error of calibration (RMSEC) values obtained were 0.9975 and 1.34% (v/v), respectively. Furthermore, the classification of lard and beef fat in meatball broth as well as in commercial samples was performed at wavenumber region of 1200-1000cm-1. The results showed that FTIR spectroscopy coupled with chemometrics can be used for quantitative analysis and classification of lard in meatball broth for Halal verification studies. The developed method is simple in operation, rapid and not involving extensive sample preparation. © 2013 Elsevier Ltd.

Ng W.P.Q.,University of Nottingham Malaysia Campus | Lam H.L.,University of Nottingham Malaysia Campus | Ng F.Y.,Malaysian Palm Oil Council | Kamal M.,University of Technology Malaysia | Lim J.H.E.,Synergy Global
Journal of Cleaner Production | Year: 2012

This paper gives an overview of the green potential of the palm biomass industry, which contributes to Malaysia's economic and sustainable development. An overall picture of the green development indicators of the country is provided based on the authors' experiences in policy making, research and business development. The emerging palm biomass industry in Malaysia is foreseen to dominate the country's directional development in the coming years, particularly when the sustainability issue is raised globally. With the increasing volume of palm oil residue accumulation due to palm oil production, palm biomass is gaining significant attention and being increasingly utilised to produce various green products as well as highly valuable biochemicals, such as bioethanol, vitamins, etc. The palm oil industry has been identified as the key industry for expansion to achieve economic advancement along with the development of greener production processes in the country. Research on palm biomass, which is actively being carried out by both private and public institutions, is categorised. Furthermore, actions and policies to promote the implementation of green technology in Malaysia, while simultaneously defending both environmental and ecological health and promoting technology transformation, are summarised. Challenges and concerns over the green future of the country are discussed, as well as the business trend in the Malaysian palm biomass industry. Copyright © 2012 Published by Elsevier Ltd. All rights reserved.

Wong W.P.,Universiti Sains Malaysia | Wong K.Y.,University of Technology Malaysia
Journal of Cleaner Production | Year: 2014

The concept of lean is important to sustain operations management. Workers are treated as important assets in lean. In this study, a 'lean-ecosphere' management system is developed for a manufacturing company by using interpretive structural modeling (ISM) and analytical network process (ANP). In the first phase of the methodology, a unified index to set a common objective of people is developed for horizontal integration. In the second phase, a hierarchical relationship model is developed to identify relationships between challenges of lean. This model facilitates the building of a strong foundation of lean to promote the depth of human integration. In the end, the results achieved are compared with the current situation of the company. The results indicated that the scientific methodology for lean management system is very beneficial for the company. This paper adds knowledge to the operations management literature by addressing the human resource factor to create a sustainable operation. © 2014 Elsevier Ltd. All rights reserved.

Atabaki M.M.,University of Technology Malaysia | Hanzaei A.T.,University of Tehran
Materials Characterization | Year: 2010

An innovative method was applied for bonding Zircaloy-4 to stabilized austenitic stainless steel 321 using an active titanium interlayer. Specimens were joined by a partial transient liquid phase diffusion bonding method in a vacuum furnace at different temperatures under 1 MPa dynamic pressure of contact. The influence of different bonding temperatures on the microstructure, microindentation hardness, joint strength and interlayer thickness has been studied. The diffusion of Fe, Cr, Ni and Zr has been investigated by scanning electron microscopy and energy dispersive spectroscopy elemental analyses. Results showed that control of the heating and cooling rate and 20 min soaking at 1223 K produces a perfect joint. However, solid-state diffusion of the melting point depressant elements into the joint metal causes the solid/liquid interface to advance until the joint is solidified. The tensile strength of all the bonded specimens was found around 480-670 MPa. Energy dispersive spectroscopy studies indicated that the melting occurred along the interface of the bonded specimens as a result of the transfer of atoms between the interlayer and the matrix during bonding. This technique provides a reliable method of bonding zirconium alloy to stainless steel. © 2010 Elsevier Inc.

Masood I.,University Tun Hussein Onn Malaysia | Hassan A.,University of Technology Malaysia
International Journal of Advanced Manufacturing Technology | Year: 2013

In multivariate quality control, the artificial neural networks (ANN)-based pattern recognition schemes generally performed better for monitoring bivariate process mean shifts and provided more efficient information for diagnosing the source variable(s) compared to the traditional multivariate statistical process control charting. However, these schemes revealed disadvantages in term of reference bivariate patterns in identifying the joint effect and excess false alarms in identifying stable process condition. In this study, feature-based ANN scheme was investigated for recognizing bivariate correlated patterns. Feature-based input representation was utilized into an ANN training and testing towards strengthening discrimination capability between bivariate normal and bivariate mean shift patterns. Besides indicating an effective diagnosis capability in dealing with low correlation bivariate patterns, the proposed scheme promotes a smaller network size and better monitoring capability as compared to the raw data-based ANN scheme. © 2012 Springer-Verlag London Limited.

Al-Mulali U.,University of Technology Malaysia
International Journal of Energy Sector Management | Year: 2014

Purpose – The purpose of this study was to investigate the relationship between gross domestic product (GDP) growth and renewable and non-renewable energy consumption in 82 developing countries categorized by region. Design/methodology/approach – To achieve the goal of this study, the panel model was used taking the period 1990-2009. Findings – The Kao co-integration test results showed that both renewable and non-renewable energy consumption had a long-running relationship with all the economic sectors in all regions. Moreover, the FMOLS revealed that the renewable and non-renewable energy consumption had a long-run positive relationship with the economic sectors. However, the results also revealed that non-renewable energy consumption has a more significant effect on the economic sectors than the renewable energy consumption. In addition, the Granger causality showed the same results, that the causal relationship between the economic sectors and non-renewable energy consumption is more significant than the causal relationship between the economic sectors and renewable energy. Practical implications – The reason behind these results is that these regions still depend on fossil fuels to promote their economic growth. Fossil fuels basically contribute more than 80 per cent of their total energy consumption. Thus, the study recommends the developing countries to increase their investment on renewable energy projects to increase the share of the renewable energy of total energy consumption. Originality/value – This study is considered different from all the previous studies because it will investigate the disaggregate relationship between GDP and energy consumption (renewable and non-renewable) in East Asia and Pacific, Europe and Central Asia, Latin America and the Caribbean, Middle East and North Africa, South Asia and the Sub-Saharan African developing countries. © Emerald Group Publishing Limited.

Kamarzaman N.A.,University Technology of MARA | Tan C.W.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

In recent decades, Photovoltaic (PV) energy has made significant progress towards meeting the continuously increasing world energy demand. Besides that, the issue of conventional fossil fuels depletion as well as environmental pollution both contribute to the growth of PV technology. However, the deployment and implementation of photovoltaic systems remain as a great challenge, since the PV material cost is still very high. The low PV module conversion efficiency is another factor that restricts the wide usage of PV systems, therefore a power converter embedded with the capability of maximum power point tracking (MPPT) integrated with PV systems is essential to further the technology. This paper provides a comprehensive review of the available MPPT techniques, both the uniform insolation and partial shaded conditions. In order to appreciate the knowledge of MPPT concepts, several types of PV cell equivalent models are explained too. Conventional MPPT techniques have proven the ability to track the maximum power point (MPP) under uniform solar irradiance. However, under rapidly changing environments and partially shaded conditions, conventional techniques have failed to track the true MPP. For this reason, stochastic based methods and artificial intelligence have been developed with the ability to seek the true MPP under multiple peaks with good convergence speed. This paper analyses and compares both conventional and stochastic MPPT techniques based on the true MPP tracking capability, design complexity, cost consideration, sensitivity to environmental change and convergence speed. Comparatively, the stochastic algorithms and artificial intelligence show excellent tracking performance. The research on MPPT techniques is ongoing towards achieving a better performance in terms of the ease of implementation, low system cost and better tracking efficiency. © 2014 Elsevier Ltd.

Mekhilef S.,University of Malaya | Faramarzi S.Z.,University of Malaya | Saidur R.,University of Malaya | Salam Z.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

Solar energy is one of the cleanest sources of alternative energy. Due to high energy demand in one hand and environmental negative impact of fossil fuels, on the other hand, many countries consider the alternative energy sources as a suitable and feasible option in industry and domestic usage. It was discovered that the different applications of solar energy in industries are being accepted more than ever. The present study is a state of art on the numerous new and feasible technologies of solar energy applications in the agricultural sectors. It discusses about the importance of solar energy as environmental clean technologies and the most reliable energy source. This study covers different types of solar energy systems like as solar photovoltaic and solar thermal for pumping water, drying crops, cooling the storages and producing heating/cooling greenhouses. It has been proven that photovoltaic systems and/or solar thermal system would be the suitable options in agricultural application and especially for the distant rural area. © 2012 Elsevier Ltd.

Goh S.M.,University of Technology Malaysia
Advances in Engineering Education | Year: 2012

The objective of this study is to evaluate the potential of a game called Star Power to teach professional skills to mechanical engineering undergraduates. The game was conducted as an activity in a final year Professional Practice unit. A survey in the form of a questionnaire was administered to participating students in the following semester of studies after a summer break. The survey showed that the majority of the students believed they had improved their professional skills from playing Star Power. Although the game is typically used in the teaching of sociology, this study demonstrated that the game can provide a rich and versatile setting in which different elements of professional skills that are important to an engineer can be incorporated and developed.

Dastjerdi A.V.,University of Melbourne | Tabatabaei S.G.H.,University of Technology Malaysia | Buyya R.,University of Melbourne
Software - Practice and Experience | Year: 2012

Cloud computing offers virtualized computing elements on demand in a pay-as-you-go manner. The major motivations to adopt Cloud services include no upfront investment on infrastructure and transferring responsibility of maintenance, backups, and license management to Cloud Providers. However, one of the key challenges that holds businesses from adopting Cloud computing services is that, by migrating to Cloud, they move some of their information and services out of their direct control. Their main concern is how well the Cloud providers keep their information (security) and deliver their services (performance). To cope with this challenge, several service level agreement management systems have been proposed. However, monitoring service deployment as a major responsibility of those systems have not been deeply investigated yet. Therefore, this paper shows how monitoring services have to be described, deployed (discovered and ranked), and then how they have to be executed to enforce accurate penalties by eliminating service level agreement failure cascading effects on violation detection. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.

Ishaque K.,Karachi Institute of Economics & Technology | Salam Z.,University of Technology Malaysia | Lauss G.,AIT Austrian Institute of Technology
Applied Energy | Year: 2014

With the rapid growth of photovoltaic (PV) systems, stringent standards are envisaged to ensure the safe and efficient generation of power. Therefore, the performance of maximum power point tracking (MPPT) element in PV system under dynamic environmental conditions is very crucial. Hence, this paper evaluates the performance of perturb and observe (P&O) and incremental conductance (IC) MPPT technique on the basis of European Efficiency Test, EN 50530, which is specifically devised for the dynamic performance of PV system. Both techniques are implemented in direct control structure and buck-boost converter is used as MPPT converter. Experiments are conducted using a custom designed PV array simulator. Results reveal that both methods yield almost equivalent dynamic MPPT efficiency. However, in average, the performance of IC method is found to be slightly better that gives 98.5% efficiency compare to 98.3% in P&O. It is also seen that the performance of IC method is very sensitive to its perturbation size, especially at low insolation levels. © 2014 Elsevier Ltd.

Chong C.T.,University of Technology Malaysia | Hochgreb S.,University of Cambridge
Applied Mechanics and Materials | Year: 2013

A model gas turbine burner was employed to investigate spray flames established under globally lean, continuous, swirling conditions. Two types of fuel were used to generate liquid spray flames: palm biodiesel and Jet-A1. The main swirling air flow was preheated to 350°C prior to mixing with airblast-atomized fuel droplets at atmospheric pressure. The global flame structure of flame and flow field were investigated at the fixed power output of 6 kW. Flame chemiluminescence imaging technique was employed to investigate the flame reaction zones, while particle imaging velocimetry (PIV) was utilized to measure the flow field within the combustor. The flow fields of both flames are almost identical despite some differences in the flame reaction zones. © (2013) Trans Tech Publications, Switzerland.

Fulazzaky M.A.,University of Technology Malaysia | Omar R.,Syarikat Air Johor Holdings Sdn Bhd
Clean Technologies and Environmental Policy | Year: 2012

Most sources of oil and grease (O&G) are insoluble in water. Because the specific gravity of O&G is lower than water, it floats on the top surface. The presence of O&G may have adverse impact on water resources management. Activated carbon can remove O&G from water by adsorption process. Still the use of physical models to adsorb O&G from stream water needs to be verified. This study proposes the mathematical models for adsorption of O&G from stream water using the granular activated carbon block filter (GACBF). The parameters in equations are all physically meaningful, and the experimental data validation shows that the equations are sufficiently accurate. The proposed models to calculate the accumulation rate, lifetime, and adsorption capacity for the adsorption of O&G onto GACBF from Ulu Pontian River water are presented to contribute to clean technology and environmental contamination investigation and assessment. © US Government 2012.

Mustapha K.B.,University of Technology Malaysia
European Journal of Computational Mechanics | Year: 2015

This study is concerned with the free vibration behaviour of a system of elastically connected functionally graded micro-scale panels. The mechanical properties of the micro-panel are assumed to have a through-thickness variation and governed by a power-law relation in terms of the constituents volume fractions. The biharmonic equations governing the motion of each micro-panel are formulated through the adoption of the energy method along with the postulates of the Kirchhoff-Love plate theory. Concentrating on the asynchronous motion of the connected micro-panels, the study investigates the shift of the natural frequencies of the system as a result of variation in the: aspect ratio of the micro-panel, span-to-thickness ratio of the micro-panel; gradient index; small-scale effect; and the ratio of the Youngs modulus. Estimates of the natural frequencies, under the assumption of simply-supported edges of the micro-panels, are provided by the Naviers solution method. The qualitative assessment of the models parameters indicates that the effect of the gradient index is stifled by the presence of the size effect. Moreover, it is observed that higher values of the ratio of the constituents Youngs modulus generate a stiffer response of the micro-panel than higher values of the connectors stiffness and the constituents density ratio. © 2015 © 2015 Taylor & Francis.

Myint Y.M.,University of Technology Malaysia
Proceedings of 2011 2nd International Conference on Instrumentation Control and Automation, ICA 2011 | Year: 2011

Autonomous robots are widely used in dangerous area and medical robotic applications. This paper addresses on the guidance system implementation for autonomous mobile robot. The main theme of this guidance system is to detect the obstacle along the predefined path of model moving area and successfully avoid this obstacle. Three PIC microcontrollers interfaced on I 2C communication protocol are the main functional unit of constructed system and ultrasonic transmitter and receiver are used for obstacle detection. The avoidance process based on line of sight to destination and interpolation technique is simulated with MATLAB ® software. After doing some modification to solve the problem faced on the whole system testing phase, it can be concluded that the guidance system can totally avoid the obstacles. © 2011 IEEE.

Danapalasingam K.A.,University of Technology Malaysia
International Journal of Pattern Recognition and Artificial Intelligence | Year: 2014

Autonomous helicopter stabilization in the presence of a wind disturbance is presented. A controller is designed based on the nonlinear adaptive output regulation and robust stabilization of a chain of integrators by a saturated feedback to stabilize the position and velocity of a helicopter. The controller is able to adaptively estimate the wind disturbance whose measurements are not made available. In addition to robustness against the external disturbance input the control design is carried out to handle helicopter parameter uncertainties. The cost of the robustly stabilizing control strategy is the challenge to tune 13 controller parameters for a desired output response. Particle swarm optimization (PSO), a metaheuristic optimization algorithm is applied to automate the tuning process. Simulation results demonstrate the effectiveness of the proposed control and tuning methods in the robust stabilization of the helicopter motion. © 2014 World Scientific Publishing Company.

Romagnoli A.,Imperial College London | Martinez-Botas R.F.,Imperial College London | Rajoo S.,University of Technology Malaysia
International Journal of Heat and Fluid Flow | Year: 2011

This paper presents the results from an experimental investigation conducted on different turbine designs for an automotive turbocharger. The design progression was based on a commercial nozzleless unit that was modified into a variable geometry single and twin-entry turbine. The main geometrical parameters were kept constant for all the configurations and the turbine was tested under steady flow conditions. A significant depreciation in efficiency was measured between the single and twin-entry configuration due to the mixing effects. The nozzleless unit provides the best compromise in terms of performance at different speeds. The twin-entry turbine was also tested under partial and unequal admissions. Based on the test results a method to determine the swallowing capacity under partial admission given the full admission map is presented. The test results also showed that the turbine swallowing capacity under unequal admission is linked to the full admission case. © 2010 Elsevier Inc.

Mohd Yazid S.N.A.,University Malaysia Sarawak | Chin S.F.,University Malaysia Sarawak | Pang S.C.,University Malaysia Sarawak | Ng S.M.,University of Technology Malaysia
Microchimica Acta | Year: 2013

We report that fluorescent carbon nanodots (C-dots) can act as an optical probe for quantifying Sn(II) ions in aqueous solution. C-dots are synthesized by carbonization and surface oxidation of preformed sago starch nanoparticles. Their fluorescence is significantly quenched by Sn(II) ions, and the effect can be used to determine Sn(II) ions. The highest fluorescence intensity is obtained at a concentration of 1. 75 mM of C-dots in aqueous solution. The probe is highly selective and hardly interfered by other ions. The quenching mechanism appears to be predominantly of the static (rather than dynamic) type. Under optimum conditions, there is a linear relationship between fluorescence intensity and Sn(II) ions concentration up to 4 mM, and with a detection limit of 0. 36 μM. © 2012 Springer-Verlag Wien.

Mekhilef S.,University of Malaya | Abdul Kadir M.N.,University of Malaya | Salam Z.,University of Technology Malaysia
IEEE Transactions on Industrial Informatics | Year: 2013

Three-stage 18-level hybrid inverter design with novel control method is presented. The inverter consists of main high-, medium-, and low-voltage stages connected in series from the output side. The high-voltage stage is a three-phase, six-switch conventional subinverter. The medium- and low-voltage stages are made of three-level subinverters constructed by H-bridge units. The proposed control strategy assumes a reference input voltage vector and aims to approximate it to the nearest inverter vector. The control concept is based on holding the high-voltage state as long as it is feasible to do so. The reference voltage vector has been represented in a 60°-spaced two axis coordinate system to reduce the computational effort. The concept of the staged-control has been presented, the transformed inverter vectors and their relation to the switching variables have been defined, and the implementation process has been described. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low switching losses. © 2012 IEEE.

Tan C.W.,University of Technology Malaysia | Green T.C.,Imperial College London | Hernandez-Aramburo C.A.,Imperial College London
Energy | Year: 2010

This paper presents a stochastic simulation using Monte Carlo technique to size a battery to meet dual objectives of demand shift at peak electricity cost times and outage protection in BIPV (building integrated photovoltaic) systems. Both functions require battery storage and the sizing of battery using numerical optimization is popularly used. However, the weather conditions, outage events and demand peaks are not deterministic in nature. Therefore, the sizing of battery storage capacity should also be based on a probabilistic approach. The Monte Carlo simulation is a rigorous method to sizing BIPV system as it takes into account a real building load profiles, the weather information and the local historical outage distribution. The simulation is split into seasonal basis for the analysis of demand shifting and outage events in order to match the seasonal weather conditions and load profiles. Five configurations of PV (photovoltaic) are assessed that cover different areas and orientations. The simulation output includes the predicted PV energy yield, the amount of energy required for demand management and outage event. Therefore, consumers can base sizing decisions on the historical data and local risk of outage statistics and the success rate of meeting the demand shift required. Finally, the economic evaluations together with the sensitivity analysis and the assessment of customers' outage cost are discussed. © 2010 Elsevier Ltd.

Sahri Z.,University Technical Malaysia Melaka | Yusof R.,University of Technology Malaysia | Watada J.,Waseda University
IEEE Transactions on Industrial Informatics | Year: 2014

Missing values are a common occurrence in a number of real world databases, and statistical methods have been developed to deal with this problem, referred to as missing data imputation. In the detection and prediction of incipient faults in power transformers using dissolved gas analysis (DGA), the problem of missing values is significant and has resulted in inconclusive decision-making. This study proposes an efficient nonparametric iterative imputation method named FINNIM, which comprises of three components: 1) the imputation ordering; 2) the imputation estimator; and 3) the iterative imputation. The relationship between gases and faults, and the percentage of missing values in an instance are used as a basis for the imputation ordering; whereas the plausible values for the missing values are estimated from bm{k}-nearest neighbor instances in the imputation estimator, and the iterative imputation allows complete and incomplete instances in a DGA dataset to be utilized iteratively for imputing all the missing values. Experimental results on both artificially inserted and actual missing values found in a few DGA datasets demonstrate that the proposed method outperforms the existing methods in imputation accuracy, classification performance, and convergence criteria at different missing percentages. © 2014 IEEE.

Kanniah K.D.,University of Technology Malaysia | Beringer J.,Monash University | Hutley L.B.,Charles Darwin University
Agricultural and Forest Meteorology | Year: 2011

Gross Primary Productivity (GPP) is a critical measure of the health and sustainability of natural ecosystems. Understanding the magnitude, spatial patterns and processes of GPP will underpin predictions of the impact of climate change on the carbon cycle. In Australia, savannas account for one third of the terrestrial carbon stores and therefore, estimating the magnitude of savanna GPP and studying the spatial relationship between GPP and environmental determinants at the regional scale is essential in understanding ecosystem responses to increasing atmospheric CO2 concentrations and climate change. In this study we employed an integrated approach combining in situ measurements, eddy covariance based flux tower data and remote sensing techniques to examine the role of environmental drivers in controlling the spatial variation in GPP of savannas in the Northern Territory (NT), Australia. We used field based light use efficiency (LUE), regional specific meteorology and Moderate Resolution Imaging Spectro-radiometer (MODIS) based fraction of absorbed Photosynthetically Active Radiation (fPAR) data to estimate GPP. The estimated GPP agreed quite well (only a 6% error) with GPP estimated from flux tower at the Howard Springs site. The spatial pattern of GPP along the Northern Australian Tropical Transect (NATT) was calculated and showed a strong gradient in GPP from the coast (12.50°S where rainfall was 1622mmyear-1) to inland (17.73°S where mean rainfall was 643mmyear-1) with a decrease of 77%. A decreasing trend in GPP with rainfall is noticed especially at the dry end of the transect studied. However, in the wet end and middle part of the transect (e.g. dominated by different Eucalyptus species), the response of GPP to changes in rainfall is reduced. This finding suggests that the influence of rainfall on various Eucalyptus species may be dampened by biotic factors. Our results suggest that future changes in precipitation driven by climate change may affect the future distribution and dynamics of GPP in northern Australia. © 2011 Elsevier B.V.

Narrein K.,Jalan Perintis U1 52 | Mohammed H.A.,University of Technology Malaysia
Journal of Computational and Theoretical Nanoscience | Year: 2014

One of the most common methods used to transfer heat is by using various types of heat exchangers. The efficiency of heat exchangers can be improved through active or passive techniques. Active technique involves the use of external forces such as vibration, rotation, electric field, etc. Where else the passive techniques involve fluid additives or modified surface geometries. Helical coiled tubes have been known to exhibit excellent heat transfer characteristics compared to regular straight tubes and for this reason it is widely used in industrial applications. Another known passive technique to enhance heat transfer is by altering the fluid thermal conductivity. Recent studies have shown that nanofluids (nano sized particles suspended in conventional heat transfer fluids) posses superior heat transfer capabilities due to its high thermal conductivity. The amount of research done in this area is fairly new and limited. Most studies done on helical coiled tubes and nanofluids show enhanced heat transfer capabilities and results that challenge conventional theories and limitations on heat transfer devices and fluids. Several important aspects of HCTHE that affect the performance such as geometry, fluid inlet and outlet arrangement, and types of HCTHE are discussed based on the reported findings from experimental and numerical studies. This review also focuses on the vital aspects of nanofluids such as types, properties and heat transfer characteristics and limitations towards the application of nanofluids. © 2014 American Scientific Publishers.

Mohammed H.A.,University of Technology Malaysia | Tabatabaeikia S.,University of Malaya | Munisamy K.M.,University of Tenaga Nasional
Journal of Computational and Theoretical Nanoscience | Year: 2014

A numerical investigation is performed to study the effects of different geometrical parameters and nanofluids on the thermal and flow fields through circular tubes fitted with inserts with Reynolds number ranging from 500 to 1750 and heat flux of 1000 W/m2. The two dimensional continuity, Navier Stokes and energy equations are solved by using the finite volume method. The optimization through twisted tape with eleven types of tube having 20 mm inner diameter was studied by changing the dimensions of twisted tape such as the width ratio (W/D) in the range of 0.2-0.8 and the twist ratio (H/D) in the range of 2.5-4 for water as a working fluid to reach the optimal geometry with maximum performance evaluation criterion (PEC). The effects of using different types of nanoparticles such as Al2O3, CuO, SiO2, and ZnO, different nanoparticles volume fractions in the range of 1% to 4% and different nanoparticles diameters in the range of 25 nm to 80 nm in water base fluid were examined. The effects of different Reynolds numbers and the dispersion of nanoparticle in different types of base fluid such as ethylene glycol, engine oil and water in circular tube were also analyzed. Simulation results show that the Nusselt number increased as the width ratio and Reynolds number increased and twist ratio decreased. The highest Nusselt number was obtained with W/D = 0-8, while the efficient flow (max. PEC) was achieved with W/D = 0-7 for H/D = 2-5. The Nusselt number through the circular tubes with insert was enhanced with the increase of the particle volume fraction and with the decrease of nanoparticles diameter. Copyright © 2014 American Scientific Publishers.

Saman N.,Advanced Materials and Process Engineering AMPEN Laboratory | Johari K.,Advanced Materials and Process Engineering AMPEN Laboratory | Mat H.,Advanced Materials and Process Engineering AMPEN Laboratory | Mat H.,University of Technology Malaysia
Microporous and Mesoporous Materials | Year: 2014

Three methods were used to synthesize sulfur-functionalized silica materials with spherical morphology: (a) impregnation of CS2 and S8 onto preformed silica support (MCM-TEOS); (b) co-condensation of TEOS and BTESPT/MPTMS; and (c) direct use of BTESPT and MPTMS as precursors. The presence of sulfur functional groups in the synthesized adsorbents was confirmed by the FTIR and EDX analyses. Lower pore arrangements and pore characteristics of sulfur-functionalized silicas were found which were observed from the XRD and nitrogen adsorption desorption analysis. However, these samples showed higher adsorption capacity than silica without sulfur. The highest Hg(II) adsorption capacity (47.50 mg/g) was obtained by the MPTMS-SMs(I) adsorbent synthesized through the co-condensation method. © 2014 Elsevier Inc. All rights reserved.

Mohamad H.,University of Technology Malaysia | Soga K.,University of Cambridge | Pellew A.,RKD Consultant Ltd | Bennett P.J.,University of Cambridge
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012

An optical fiber strain-sensing technique, on the basis of Brillouin optical time domain reflectometry (BOTDR), was used to monitor the performance of a secant pile wall subjected to multiple props during construction of an adjacent basement in London. Details of the installation of sensors and data processing are described. Distributed strain profiles were obtained by deriving strain measurements from optical fibers installed on opposite sides of the pile to allow monitoring of both axial and lateral movements along the pile. Methods for analyzing the thermal strain and temperature compensation are also presented. Measurements obtained from the BOTDR were found to be in good agreement with inclinometer data from the adjacent piles. The relative merits of the two different techniques are discussed. © 2011 American Society of Civil Engineers.

Rezaei J.,Iran University of Science and Technology | Shahbakhti M.,Michigan Technological University | Bahri B.,Islamic Azad University at Shahreza | Aziz A.A.,University of Technology Malaysia
Applied Energy | Year: 2015

Butanol and ethanol are promising conventional fuel alternatives particularly when utilized in advanced combustion mode like homogeneous charge compression ignition (HCCI). This study investigates the performance and emission characteristics of HCCI engines fueled with oxygenated fuels (i.e. butanol and ethanol). The investigation is done through a combination of experimental data analysis and artificial neural network (ANN) modeling.This study uses HCCI experimental data to characterize variations in seven engine performance metrics including indicated mean effective pressure (IMEP), thermal efficiency, in-cylinder pressure, net total heat released, nitrogen oxides (NOx), carbon monoxide (CO), and total hydrocarbon (THC) concentrations. Two types of ANNs including radial basis function (RBF) and feedforward (FF) are developed to predict the seven engine performance metrics. The experimental data at 123 HCCI operating points from two different engines are collected to validate the ANN models. The validation results indicate both RBF and FF models can predict HCCI engine performance metrics with less than 4% error for butanol and ethanol fueled engines. The results show that the FF neural network models are advantageous in terms of network simplicity with fewer required neurons but need twice as much training time compared to the RBF models. © 2014 Elsevier Ltd.

Fulazzaky M.A.,University of Technology Malaysia
Environmental Monitoring and Assessment | Year: 2013

Surface water is one of the essential resources for supporting sustainable development. The suitability of such water for a given use depends both on the available quantity and tolerable quality. Temporary status for a surface water quality has been identified extensively. Still the suitability of the water for different purposes needs to be verified. This study proposes a water quality evaluation system to assess the aptitude of the Selangor River water for aquatic biota, drinking water production, leisure and aquatic sport, irrigation use, livestock watering, and aquaculture use. Aptitude of the water has been classified in many parts of the river segment as unsuitable for aquatic biota, drinking water production, leisure and aquatic sport as well as aquaculture use. The water quality aptitude classes of the stream water for nine locations along the river are evaluated to contribute to decision support system. The suitability of the water for five different uses and its aquatic ecosystem are verified. © 2012 Springer Science+Business Media B.V.

Chow M.F.,Academia Sinica, Taiwan | Yusop Z.,University of Technology Malaysia | Shirazi S.M.,University of Malaya
Environmental Monitoring and Assessment | Year: 2013

Information on the pollution level and the influence of hydrologic regime on the stormwater pollutant loading in tropical urban areas are still scarce. More local data are still required because rainfall and runoff generation processes in tropical environment are very different from the temperate regions. This study investigated the extent of urban runoff pollution in residential, commercial, and industrial catchments in the south of Peninsular Malaysia. Stormwater samples and flow rate data were collected from 51 storm events. Samples were analyzed for total suspended solids, 5-day biochemical oxygen demand, chemical oxygen demand, oil and grease (O&G), nitrate nitrogen (NO3-N), nitrite nitrogen, ammonia nitrogen, soluble reactive phosphorus, total phosphorus (TP), and zinc (Zn). It was found that the event mean concentrations (EMCs) of pollutants varied greatly between storm characteristics and land uses. The results revealed that site EMCs for residential catchment were lower than the published data but higher for the commercial and industrial catchments. All rainfall variables were negatively correlated with EMCs of most pollutants except for antecedent dry days (ADD). This study reinforced the earlier findings on the importance of ADD for causing greater EMC values with exceptions for O&G, NO3-N, TP, and Zn. In contrast, the pollutant loadings are influenced primarily by rainfall depth, mean intensity, and max 5-min intensity in all the three catchments. Overall, ADD is an important variable in multiple linear regression models for predicting the EMC values in the tropical urban catchments. © 2013 Springer Science+Business Media Dordrecht.

Ng R.T.L.,University of Nottingham Malaysia Campus | Hassim M.H.,University of Technology Malaysia | Ng D.K.S.,University of Nottingham Malaysia Campus
AIChE Journal | Year: 2013

Over the last decade, utilization of biomasses is highly encouraged to conserve scarce resources, reduce dependency on energy imports as well as protect the environment. Integrated biorefinery emerged as noteworthy concept to integrate several conversion technologies to have more flexibility in product generation with energy self-sustained and reduce the overall cost of the process. Integrated biorefinery is a processing facility that converts biomass feedstocks into a wide range of value added products via multiple technologies. In this work, a systematic approach for the synthesis and optimization of a sustainable integrated biorefinery which considers economic, environmental, inherent safety, and inherent occupational health performances is presented. Fuzzy optimization approach is adapted to solve four parameters simultaneously as they are often conflicting in process synthesis and optimization of an integrated biorefinery. An integrated palm oil-based biorefinery case study is solved to demonstrate the proposed approach. © 2013 American Institute of Chemical Engineers.

Anaerobic treatment processes to remove organic matter from palm oil mill effluent (POME) have been used widely in Malaysia. Still the amounts of total organic and total mineral released from POME that may cause degradation of the receiving environment need to be verified. This paper proposes the use of the hydrodynamic equations to estimate performance of the cascaded anaerobic ponds (CAP) and to calculate amounts of total organic matter and total mineral released from POME. The CAP efficiencies to remove biochemical oxygen demands, chemical oxygen demands, total solids and volatile solids (VS) as high as 94.5, 93.6, 96.3 and 98.2 %, respectively, are estimated. The amounts of total organic matter and total mineral as high as 538 kg VS/day and 895 kg FS/day, respectively, released from POME to the receiving water are calculated. The implication of the proposed hydrodynamic equations contributes to more versatile environmental assessment techniques, sometimes replacing laboratory analysis. © 2012 Springer-Verlag.

Lee S.C.,University of Technology Malaysia | Lintang H.O.,Ibnu Sina Institute for Fundamental Science Studies | Yuliati L.,Ibnu Sina Institute for Fundamental Science Studies
Chemistry - An Asian Journal | Year: 2012

A urea precursor was used for the first time to prepare mesoporous carbon nitride (MCN) by a thermal polymerization process with silica nanospheres as a hard template. Although the prepared MCN samples have similar structures and optical properties, it was revealed that the specific surface area, pore-size distribution, and morphology of the MCN samples depend on the initial mass ratio of urea to silica. Compared to the bulk carbon nitride (BCN) that only gave 20 % phenol removal (6 h of irradiation), the activities can be enhanced up to 74 % on MCN samples for photocatalytic removal of phenol under visible-light irradiation. The highest conversion was obtained on MCN with an initial mass ratio of urea to silica of 5, which has high surface area of 191 m 2 g -1 and a nanoporous structure with uniform pore-size distribution of 7 nm. In addition to the high activity, the MCN sample also showed high photocatalytic stability. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Suhaila J.,University of Technology Malaysia | Jemain A.A.,National University of Malaysia
Theoretical and Applied Climatology | Year: 2012

This study presents the spatial analysis of daily rainfall intensity and concentration index over Peninsular Malaysia. Daily rainfall data from 50 rainfall stations are used in this study. Due to the limited number of stations, the geostatistical method of ordinary kriging is used to compute the values of daily rainfall concentration and intensity and to map their spatial distribution. The resultant analysis of rainfall concentration indicated that the distribution of daily rainfall is more regular over the west, northwest and southwest regions compared to the east. Large areas of the eastern Peninsula display an irregularity in distribution of daily rainfall. In terms of number of rainy days, analysis of daily rainfall confirms that a large number of rainy days across the Peninsula arise from low-intensity events but only contribute a small percentage of total rain. On the other hand, a low frequency of rainy days with high-intensity events contributes the largest percentage of total rain. The results indicated that the total rain in eastern areas is mainly contributed by the high-intensity events. This finding explains the occurrence of a large number of floods and soil erosions in these areas. Therefore, precautionary measures should be taken earlier to prevent any massive destruction of property and loss of life due to the hazards. These research findings are of considerable importance in providing enough information to water resource management, climatologists and agriculturists as well as hydrologists for planning their activities and modelling processes. © 2011 Springer-Verlag.

Che Man S.H.,University of New South Wales | Che Man S.H.,University of Technology Malaysia | Thickett S.C.,University of New South Wales | Whittaker M.R.,University of New South Wales | Zetterlund P.B.,University of New South Wales
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2013

Polystyrene particles "armoured" with nanosized graphene oxide (GO) sheets have been prepared by aqueous miniemulsion polymerization of styrene, exploiting the amphiphilic properties of GO in the absence of conventional surfactants. The nanoscale GO sheets were prepared from graphite nanofibers of diameter approximately 100 nm based on a novel procedure, thus effectively ensuring the absence of larger sheets. Polymerization proceeded to high conversion with minor coagulation, with final number-average particle diameters of approximately 500 nm, but relatively broad particle size distributions. Scanning electron microscopy analysis revealed particles with a textured surface, consistent with the expected morphology. Interestingly, analysis of GO sheets recovered from the polymerization revealed that the GO sheets are partially reduced during the polymerization-approximately 50% of the initial carboxyl groups of the GO were lost, consistent with some loss in colloidal stability at high conversion. The overall approach offers a convenient and attractive synthetic route to novel graphene-based polymeric nanostructures. © 2012 Wiley Periodicals, Inc.

Fadzli Abd Rahman S.,University of Technology Malaysia | Fadzli Abd Rahman S.,Hokkaido University | Kasai S.,Hokkaido University | Manaf Hashim A.,Malaysia Japan International Institute of Technology | Manaf Hashim A.,Ibnu Sina Institute for Fundamental Science Studies
Applied Physics Letters | Year: 2012

A chemically doped graphene-based three-branch nanojunction device is fabricated on a SiO 2/p-Si substrate, and its nonlinear operation is characterized at room temperature (RT). By polyethyleneimine doping, the fabricated device shows improved field effect mobility of 14 800 and 16 100 cm 2/Vs for electron and holes, respectively. The device clearly exhibits nonlinearity in voltage transfer curves at RT. The curvature of the transfer curve can be controlled by using the back gate voltage, and its polarity abruptly switches near the Dirac point because of the carrier type change. The observed behaviour can be quantitatively explained in terms of the difference in the amounts of gate-induced carriers in the two input branches. © 2012 American Institute of Physics.

Mohamed Ali M.S.,University of British Columbia | Mohamed Ali M.S.,University of Technology Malaysia | Takahata K.,University of British Columbia
Sensors and Actuators, A: Physical | Year: 2010

This paper reports the wireless control of bulk-micromachined shape-memory-alloy actuators using external radiofrequency magnetic fields and its application to microgrippers. The frequency-sensitive wireless resonant heater to which the gripper actuator is bonded is activated only when the field frequency is tuned to the resonant frequency of the heater. A batch-compatible bonding technique based on photo-defined copper electroplating is developed to mechanically and thermally couple the gripper with the planar heater circuit fabricated using copper-clad polyimide film. The actuation range of 600 μm as the tip opening distance is obtained with normally closed 5-mm long grippers at a device temperature of 92 °C. The field frequency range to which the devices with 140-MHz resonant frequency respond is measured to be ∼13 MHz about the resonant frequency. The manipulation of vertically aligned carbon-nanotube forests is experimentally demonstrated. Mechanical stress tests for the bond formed by the developed electroplating bonding method show a shear strength greater than 40 MPa. © 2010 Elsevier B.V. All rights reserved.

Akram G.,University of Technology Malaysia
IEEE Antennas and Propagation Magazine | Year: 2010

The accepted dosimetric measure of electromagnetic (EM) exposure is the specific absorption rate (SAR), which is defined as the power absorbed per unit mass of tissue. International standards for compliance testing of hand-held mobile communication devices define various cubical averaging schemes to obtain the spatial peak averaged specific absorption rate. In this paper, a numerical approach to illustrate the validation and uncertainty contributions of a SAR post-processing algorithm is described. Simplified interpolation and extrapolation techniques to calculate the 1g SAR for a 2.5 mm mesh grid are evaluated. Furthermore, using linear, nearest, and spline interpolation in MATLAB, the effects of the extrapolation order on the assessment of the resultant error are examined. © 2006 IEEE.

Chua L.S.,University of Technology Malaysia
Phytotherapy Research | Year: 2014

Till to date, the advancement ofmedical science and technology is still unable to provide inclusive treatment to liver inflammation caused by neither microbial invasion nor antibiotics nor environmental toxins. Therefore, this article provides the basic knowledge of liver inflammation up to the cellular level and its current medical treatment for inflammatory symptom suppression. Because of the adverse effects of drug treatment, people start looking for comprehensive alternative nowadays. Herbal medicine is believed to be the best of choice because it is being practiced until now for centuries. Although numerous herbal plants have been reported for their efficacies in liver protection, Andrographis paniculata is the most widely used herb for hepatoprotection, particularly in Ayurveda and traditional Chinese medicine. This review covers the significant observation on the biochemical responses due to the experimental induction of liver damage in vitro and in vivo using the marker compound of the herb, namely andrographolide and its derivatives. The standardized extract of A. paniculata with the right phytochemical composition of diterpenic labdanes is likely to have tremendous potential for the development of hepatoprotective medicine. This standardized herbal medicine may not provide immediate remedy, but it can be considered as a comprehensive therapy for liver inflammation. Copyright © 2014 John Wiley & Sons, Ltd.

Colenbrander S.,University of Leeds | Gouldson A.,University of Leeds | Sudmant A.H.,University of Leeds | Papargyropoulou E.,University of Technology Malaysia
Energy Policy | Year: 2015

Where costs or risks are higher, evidence is lacking or supporting institutions are less developed, policymakers can struggle to make the case for low-carbon investment. This is especially the case in developing world cities where decision-makers struggle to keep up with the pace and scale of change. Focusing on Palembang in Indonesia, this paper considers the economic case for proactive investment in low-carbon development. We find that a rapidly growing industrial city in a developing country can reduce emissions by 24.1% in 2025, relative to business as usual levels, with investments of USD405.6 million that would reduce energy expenditure in the city by USD436.8 million. Emissions from the regional grid could be reduced by 12.2% in 2025, relative to business as usual trends, with investments of USD2.9 billion that would generate annual savings of USD175 million. These estimates understate the savings from reduced expenditure on energy subsidies and energy infrastructure. The compelling economic case for mainstreaming climate mitigation in this developing country city suggests that the constraints on climate action can be political and institutional rather than economic. There is therefore a need for more effective energy governance to drive the transition to a low-carbon economy. © 2015 The Authors.

Hussain M.S.,University of Technology Malaysia
Transactions of the Institute of Metal Finishing | Year: 2012

An innovative process for electrodepositing Ni-Co alloy coatings directly on Ti surfaces without the need to carry out the traditional pretreatment of the substrates and pre-plating with an intermediate metallic layer is discussed. Currently in the electroplating industry the naturally occurring oxide layers present on Ti surfaces are first removed by acid etching and the surface plated with a displacement reaction. In this work, by using a turbulent electrolyte flow and by varying the applied current densities, Ni-Co alloy has been electrodeposited directly on Ti surfaces at a plating rate exceeding 700 mm per hour. FESEM and XRD techniques have been used to characterise these coatings. Results confirm that these coatings are homogeneous, nanocrystalline in nature and appear to be well bonded to the substrate without any distortion or cracks at the interface. Currently this method of turbulent solution flow of electrolyte is the only means of obtaining fast rate of electrodeposition directly on titanium surfaces without usual pre-treatment. © 2012 Institute of Metal Finishing.

Riaz A.,University of Technology Malaysia | Riaz A.,COMSATS Institute of Information Technology | Zahedi G.,Missouri University of Science and Technology | Klemes J.J.,University of Pannonia
Journal of Cleaner Production | Year: 2013

bstract Growing population and expanding economies are important causes of increasing global energy demand. In wake of the continuous hike in the petroleum prices, depleting world resources and increased constant threat to planet's environment, the need for environment friendly alternative fuels has augmented many times. Methanol has been in the limelight over the past few years. High production cost, catalyst deactivation, economy of scale, huge energy requirements are the leading bottlenecks, which should be resolved to move towards the cleaner production. To address the issues, various reactors and their configurations have been modelled over years and the need to summarise all these efforts seems obligatory. One-dimensional to three-dimensional models for traditional packed bed reactors to processes for direct conversion of natural gas to methanol is available in literature. The presented study is an attempt to compile most of these efforts in order to guide future work in this area for cleaner and healthier environment.

Jayasingh S.,University of Technology Malaysia | Eze U.C.,Monash University
International Journal of e-Business Research | Year: 2012

Research on the development, intention to use, and the use of mobile coupons is scanty, particularly in developing countries such as Malaysia. Therefore, this paper examines consumers' intention to use mobile coupon (m-coupon). The authors considered several factors and developed the conceptual framework underpinned on an extended Technology Adoption Model (TAM). The data analysis was based on 781 valid responses from four locations in Malaysia. The results indicate that perceived usefulness, attitude, and social factor influence the behavior and intention of consumers to use mobile coupons. The results also indicate that gender and price consciousness emerged significant as moderating variables. The findings in this paper could be useful in extending existing knowledge on what matters most to those considering the use of mobile coupons, and eventually provide a deeper insight into what are needed for consumers to deploy this innovation. This knowledge would also help to design and develop improved mobile coupon applications. Finally, the authors discussed several research and management implications, and suggestions for future research. Copyright © 2012, IGI Global.

Bin Darus M.Y.,University Technology of MARA | Abu Bakar K.,University of Technology Malaysia
International Journal of Digital Content Technology and its Applications | Year: 2011

The purpose of this study is to propose a new congestion control framework for uni-priority of event-driven safety messages in VANETs. The uni-priority congestion is caused by the traffic of the same priority. Many of event-driven safety applications developed for VANETs is required real-time communication with high reliability and must be delivered before certain time deadline. In high load traffic, the CCH communication channel easily congested. Many studies [2,10,11,12] recommended congestion control approach to control the load and congestion on the wireless channel in VANETs. Our proposed congestion control will reserve the CCH communication channel for event-driven safety messages if the number of safety messages in the queue exceeds a defined threshold or the congestion control detect event-driven safety message. In normal traffic, the CCH communication channel is not reserve for event-driven safety messages. This research will adapt priority-based Earliest Deadline First (EDF) scheduling algorithms in proposed congestion control to schedule uni-priority of eventdriven safety messages. In addition, to provide reliability performance for event-driven safety messages, we will develop a new rebroadcasting scheme to prevent broadcast storm. In next phase of study, we plan to test and evaluate performance of our congestion control approach using network simulator e.g. NS-3.

Khosravani M.R.,University of Technology Malaysia
Applied Mechanics and Materials | Year: 2012

Using Composite materials are growing more and more today and we have to use them in possible situation. One of the Composite materials applications is on the Airplane and aero space. Reduction of Airplane weight and more adaptability with nature are examples of benefit of using composite materials in aerospace industries. In this article process of manufacturing of composite materials and specially carbon fiber composite are explained. Advance composite materials are common today and are characterized by the use of expensive, high-performance resin systems and high-strength, high-stiffness fiber reinforcement. The aerospace industry, including military and commercial aircraft of all types, is the major customer for advanced composites. Product range now includes materials for low pressure and low temperature. Some using composite materials in aero space are as follow: Satellite Components, Thin Walled Tubing for Aircraft and Satellites, launch vehicle components and honeycomb structures. © (2012) Trans Tech Publications, Switzerland.

Kueh A.B.H.,University of Technology Malaysia
Mechanics of Materials | Year: 2012

This paper presents the formulation of the hyperelastic strain energy density function for triaxial weave fabric composites. The energy function, which comprises three components: matrix, tow, and interaction, demonstrates a nonlinear stress-strain response. The model constitutes the material expressions, initial straightening and elastic recovery coefficients, which carry mechanical meaning, properly defined on the basis of micromechanics and elementary structural theory. In the solution, existing widely used but highly iterative fitting procedure that can be cumbersome and computationally expensive is circumvented. It is found that this model captures the experimental response with exceptional agreement in both longitudinal and transverse stretching. During in-plane uniaxial tension, affected invariants are those aligned along the load direction and those off-axis, corresponding to longitudinal and transverse stretching, respectively. Mechanical isotropy has been found valid only in low strain regime. Regardless of load direction, matrix and interaction energies are found to be of isotropic nature. © 2012 Elsevier Ltd. All rights reserved.

Jusoh M.,University Malaysia Perlis | Jamlos M.F.,University Malaysia Perlis | Kamarudin M.R.,University of Technology Malaysia
Microwave and Optical Technology Letters | Year: 2012

A novel small size planar monopole antenna operating from 0.1 to 1100 MHz is proposed. A planar monopole antenna constructed with 148 mm × 64 mm of radiating element and 80 mm square of ground plane is suitable for cognitive radio (CR) applications where it can cover a very high frequency and a partial of ultra high frequency (UHF) band for spectrum sensing. The proposed monopole antenna is designed by combining a beveling technique and resistor lumped element loading by employing FR4 substrate for low-cost intention. The integration of the resistor with double bevel contributes to the behavior of an inductor as more current are excited to the ground eventually making the radiating element becomes more magnetic. Furthermore, it is found that 50° of dual bevel angle give optimization results for the impedance bandwidth of the antenna. As a result, the low frequency has shifted to the left and enhanced the antenna's impedance bandwidth significantly from 2.2:1 (103%) to 11:1 (200%). The proposed antenna is also extensively proficient in producing divisive radiation patterns with vertical polarization at four different frequencies; 200, 500, 800, and 1000 MHz. The presented antenna performances clarify the potential of the approach between simulation and the measurement results. Instead of CR, the proposed antenna has attractive potentials to be used for GSM, broadcasting, UHF radio frequency identification (RFID) and radio astronomy applications in the future. © 2011 Wiley Periodicals, Inc.

Marghany M.,University of Technology Malaysia
Global Nest Journal | Year: 2014

This study aims at modelling three-dimensional shoreline change rates using differential interferometric synthetic aperture radar (DInSAR) techinuqe. Neverthless, decorrelation plays significant role to control the accuracy of three dimensional object reconstruction using DInSAR. To solve this problem, multichannel MAP height estimator algorithm is implemented with in ENVISAT ASAR data. Therefore, the proposed method has been applied to coastaline of Johor, Malaysia. The study shows the critical erosion of -3.5 m y-1 with accuracy (RMSE) of ±0.05 m. In addition, the volume rate of shoreline changes of -2343.42 m3 y-1 corresponds to the lowest digital elevation model (DEM) of 7.4 m. It can be said that accurate rate of shoreline change can be achieved with root mean square error (RMSE) of ±0.05 m using multichannel MAP height estimator algorithm. © 2014 Global NEST Printed in Greece. All rights reserved.

Mohamed N.,University of Technology Malaysia | Ahmad I.H.,International Islamic University Malaysia
Computers in Human Behavior | Year: 2012

The research aims at gaining insights into information privacy concerns, its antecedents and privacy measure use in social networking sites. The Social Cognitive, Protection Motivation theories and gender factor were used as a basis to develop and confirm a research model. Using a cross-sectional survey design and cluster sampling technique, four-hundred thirteen questionnaires were distributed to undergraduates at a public Malaysian university; three-hundred forty were included in analyses. Data was analyzed using structural equation modeling technique. Results suggest that in order of importance only perceived severity, self-efficacy, perceived vulnerability, and gender are antecedents of information privacy concerns with social networking sites; response efficacy and rewards were not significant antecedents contrary to many past findings in the literature that used Social Cognitive and Protection Motivation Theory as a theoretical basis. Information privacy concerns explain privacy measure use in social networking sites. The implications of these results and study limitations are discussed. © 2012 Elsevier Ltd. All rights reserved.

Vanaki S.,University of Malaya | Mohammed H.A.,University of Technology Malaysia
International Communications in Heat and Mass Transfer | Year: 2015

A numerical investigation is performed to study the effects of different rib shapes and turbulent nanofluid flow on the thermal and flow fields through transversely roughened rectangular channels with Reynolds number ranging from 5000 to 20000 and uniform heat flux of 10kW/m2. Considering single-phase approach, the two-dimensional continuity, Navier-Stokes, and energy equations were solved by using the finite volume method (FVM). The optimization was carried out by using various rib shapes (rectangular shape, triangular shape, wedge pointing upstream, and wedge pointing downstream) in two arrangements (in-line and staggered) and three different aspect ratios (w/e=0.5, 2, and 4) to reach the optimal geometry with maximum performance evaluation criterion (PEC). The main aim of this study is to analyze the effects of nanoparticle types (Al2O3, CuO, SiO2, and ZnO), concentration (1-4%), and nanoparticle diameter (30-80nm), on the heat transfer and fluid flow characteristics. Simulation results show that the ribbed channels' performance was greatly influenced by rib shapes and their geometrical parameters. The highest PEC was obtained for the in-line triangular ribs with w/e=4 at Re=5000. It is found that the water-SiO2 shows the highest heat transfer enhancement compared with other tested nanofluids. The Nusselt number through the ribbed channels was enhanced with the increase of the particle volume fraction and Reynolds number, and with the decrease of nanoparticle diameter. © 2015 Elsevier Ltd.

Al-Odaini N.A.,University Putra Malaysia | Zakaria M.P.,University Putra Malaysia | Yaziz M.I.,University Putra Malaysia | Surif S.,University of Technology Malaysia
Journal of Chromatography A | Year: 2010

Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with 30min total run time. River water samples (150mL) and (sewage treatment plant) STP effluents (100mL) adjusted to pH 2, were loaded into MCX (3cm3, 60mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC-ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865ng/L in STP effluent, and 182ng/L in river water. © 2010 Elsevier B.V.

Mirzal A.,University of Technology Malaysia
International Journal of Multimedia and Ubiquitous Engineering | Year: 2012

We present a simple web search engine for indexing and searching html documents using python programming language. Because python is well known for its simple syntax and strong support for main operating systems, we hope it will be beneficial for learning information retrieval techniques, especially web search engine technology.

Salam Z.,University of Technology Malaysia | Ramli M.Z.,University Technical Malaysia Melaka
2012 IEEE Energy Conversion Congress and Exposition, ECCE 2012 | Year: 2012

In a typical photovoltaic (PV) power system, when part of the PV module is shaded, the bypass diode is activated to protect the module from hot-spot damages. As a result, the output power is reduced significantly because the power generated from the shaded module is totally unusable. In this paper, a simple circuit is proposed to increase the power yield of PV system under partial shading condition. The idea is to recover the power generated by the shaded module and then process it using power electronics circuit to become part of the output power. Consequently, the inclusion of the circuit enables the system to deliver more power compared to the bypass diode method. The concept is evaluated using Matlab-Simulink simulation and proven using an experimental test rig. The performance of the proposed circuit is compared with (1) PV system with bypass diode and (2) micro-inverter. The results show marked improvement in the efficiency, especially under heavy partial shading condition © 2012 IEEE.

Kumar Y.J.,University Technical Malaysia Melaka | Salim N.,University of Technology Malaysia
Journal of Computer Science | Year: 2012

Problem statement: Text summarization can be of different nature ranging from indicative summary that identifies the topics of the document to informative summary which is meant to represent the concise description of the original document, providing an idea of what the whole content of document is all about. Approach: Single document summary seems to capture both the information well but it has not been the case for multi document summary where the overall comprehensive quality in presenting informative summary often lacks. It is found that most of the existing methods tend to focus on sentence scoring and less consideration is given to the contextual information content in multiple documents. Results: In this study, some survey on multi document summarization approaches has been presented. We will direct our focus notably on four well known approaches to multi document summarization namely the feature based method, cluster based method, graph based method and knowledge based method. The general ideas behind these methods have been described. Conclusion: Besides the general idea and concept, we discuss the benefits and limitations concerning these methods. With the aim of enhancing multi document summarization, specifically news documents, a novel type of approach is outlined to be developed in the future, taking into account the generic components of a news story in order to generate a better summary. © 2012 Science Publications.

Rehman A.,University of Technology Malaysia | Saba T.,King Abdulaziz University
Artificial Intelligence Review | Year: 2012

Information security paradigm is under a constant threat in enterprises particularly. The extension of World Wide Web and rapid expansion in size and types of documents involved in enterprises has generated many challenges. Extensive research has been conducted to determine the effective solutions to detect and respond but still the space is felt for improvement. Factors that hinder the development of an accurate detection and response techniques have shown links to the amount of data processing involved, number of protocols and application running across and variation in users’ requirements and responses. This paper is aimed at discussing the current issue in artificial intelligent (A.I.) techniques that could help in developing a better threat detection algorithm to secure information in enterprises. It is also investigated that the current information security techniques in enterprises have shown an inclination towards A.I. Conventional techniques for detection and response mostly requires human efforts to extract characteristics of malicious intent, investigate and analyze abnormal behaviors and later encode the derived results into the detection algorithm. Instead, A.I. can provide a direct solution to these requirements with a minimal human input. We have made an effort in this paper to discuss the current issues in information security and describe the benefits of artificially trained techniques in security process. We have also carried out survey of current A.I. techniques for IDS. Limitations of the techniques are discussed to identify the factors to be taken into account for efficient performance. Lastly, we have provided a possible research direction in this domain. © 2012, Springer Science+Business Media Dordrecht.

Taibi F.,University of Technology Malaysia
International Journal of Software Engineering and its Applications | Year: 2012

Collaborative development has been identified as one of the most important keys to the success of a software project. An effective collaboration has a great impact on the requirements specification phase since the latter involves several people specifying the requirements of various stakeholders. Such collaboration requires automatically detecting the parallel changes or revisions that are made to a shared specification. These revisions are aimed at reaching a specification that satisfies the needs of all the stakeholders. Hence, combining these changes systematically must also incorporate the detection and resolution of any merging conflicts in order to commit them properly to the shared specification leading to a sound and consistent result. A new approach is proposed in this paper to extract and integrate the parallel changes made to Object-Oriented formal specifications in a collaborative development environment. A formal foundation is proposed to uniformly define merging conflicts and the proposed approach allows combining the parallel changes made while addressing any merging conflicts at the same time. Evaluating the developed algorithms has shown good signs in terms of accuracy and scalability.

Ahmad N.,University of Technology Malaysia
International Conference on Research and Innovation in Information Systems, ICRIIS | Year: 2013

All universities in Malaysia are required to use a variety of teaching-learning methods, especially self-directed and long life learning, and the use of information and communication technology. Self-directed learning methods encourage students to recognise their needs and manage their learning, as well as deepen their understanding using complimentary activities. Therefore, student self-knowledge is essential. One aim of 'open learner models' is to encourage reflection, independent learning and formative assessment/progress monitoring, which fits well with the self-directed learning approach. An open learner model is part of a computer-based interactive learning environment where the individual learner can view information about their knowledge, difficulties and misconceptions. Using the simple independent open learner model, this paper present students' interest in viewing their learner model and considers the potential for open learner models as an approach to encourage self-directed and long life learning amongst students in institutes of higher learning in Malaysia. © 2013 IEEE.

Hadibarata T.,University of Technology Malaysia | Kristanti R.A.,Yamanashi University
Bioprocess and Biosystems Engineering | Year: 2013

Armillaria sp. F022 is a white-rot fungus isolated from a tropical rain forest in Indonesia that is capable of utilizing pyrene as a source of carbon and energy. Enzymes production during the degradation process by Armillaria sp. F022 was certainly related to the increase in biomass. In the first week after incubation, the growth rate rapidly increased, but enzyme production decreased. After 7 days of incubation, rapid growth was observed, whereas, the enzymes were produced only after a good amount of biomass was generated. About 63 % of pyrene underwent biodegradation when incubated with this fungus in a liquid medium on a rotary shaker (120 rpm, 25 °C) for 30 days; during this period, pyrene was transformed to five stable metabolic products. These metabolites were extracted in ethyl acetate, isolated by column chromatography, and then identified using thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). 1-Hydroxypyrene was directly identified by GC-MS, while 4-phenanthroic acid, 1-hydroxy-2-naphthoic acid, phthalic acid, and protocatechuic acid were identified to be present in their derivatized forms (methylated forms and silylated forms). Protocatechuic acid was the end product of pyrene degradation by Armillaria sp. F022. Dynamic profiles of two key enzymes, namely laccase and 1,2-dioxygenase, were revealed during the degradation process, and the results indicated the presence of a complicated mechanism in the regulation of pyrene-degrading enzymes. In conclusion, Armillaria sp. F022 is a white-rot fungus with potential for application in the degradation of polycyclic aromatic hydrocarbons such as pyrene in the environment. © 2012 Springer-Verlag.

Bakhary N.,University of Technology Malaysia
Jurnal Teknologi | Year: 2010

Artificial Neural Network (ANN) has been widely applied to detect damages in structures based on structural vibration modal parameters. However, uncertainties that inevitably exist in finite element model and measured vibration data might lead to false or unreliable prédiction of structural damage. In this study, a statistical approach is proposed to include the efTect of uncertainties in the ANN algorithm for damage prédiction. ANN is used to predict the stiffness parameters of structures from measured structural vibration frequencies and mode shapes. Uncertainties in the measured data and finite element model of the structure are considered in the prédiction. The statistics of the identified parameters are determined using Rossenblueth's point estimation method and verified by Monte Carlo simulation. The results show that by considering these uncertainties in the ANN model, the damages can be detected with a higher confidence level. © Universiti Teknologi Malaysia.

Liew H.-L.,Stanford University | Pinsky P.M.,University of Technology Malaysia
International Journal for Numerical Methods in Engineering | Year: 2010

For multiple-frequency full-field solutions of the boundary value problem describing small fluid-structure interaction vibration superimposed on a nominal state with prestress, we propose an efficient reduced order method by constructing the full-field matrix-Padé approximant of its finite element matrix function. Exploiting the matrix-Padé via Lanczos connection, the Padé coefficients are computed in a stable and efficient way via an unsymmetric, banded Lanczos process. The full-field Padé-type approximant is the result of one-sided projection onto Krylov subspace, we established its order of accuracy, which is not maximal. The superiority of this method in terms of various problem dimensions and parameters is established by complexity analysis via flop counts. Numerical examples obtained by using a model problem verified the accuracy of this full-field matrix-Padé approximant. © 2010 John Wiley & Sons, Ltd.

Jusan M.B.M.,University of Technology Malaysia
Open House International | Year: 2010

Meeting human needs is considered as fundamental to sustainable human settlement. However, in micro level developments particularly in respect of a housing unit, for example, an operational definition of sustainability which will be useful in its practical implementation, has yet to be developed. To address this, the author posits that theories on the relationship between the environment and the person can be taken as a conceptual frame of reference. One of them is the theory of Person-Environment Congruence (PEC). This theory conceptualizes "congruence" as the favourable outcome of the person-environment relationship. Achieving PEC is considered as the most important criteria that supports the concept of housing sustainability. In the context of housing, the author considers that PEC is achieved when the dwelling place can offer its inhabitants a place which meets their basic needs. In order to operationalize this concept in terms of housing unit design, the author propagates the use of the Means-End Chain (MEC) research model to explore the relationship between a person and his or her environment. The combination of the two concepts facilitates the identification of those housing attributes emphasized in the home-making process, together with the users' perceptual orientation towards those attributes. To experiment with the application of the MEC research model in respect of exploring the concept of PEC, a case study was conducted on 15 renovated and personalized houses in a mass housing scheme in Malaysia. The traditional MEC methods were maintained with some modifications to accommodate the various housing characteristics. The results suggest that the MEC research model is able to link the relevant housing unit attributes to user values, and it is potentially applicable in the design of a housing unit. The results also indicated that user participation is essential in home making process, in order to achieve and maintain sustainability.

Marghany M.,University of Technology Malaysia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

The merchant ship collided with a Malaysian oil tanker on May 25, 2010, and spilled 2,500 tons of crude oil into the Singapore Straits. The main objective of this work is to design automatic detection procedures for oil spill in synthetic aperture radar (SAR) satellite data. In doing so the genetic algorithm tool was designed to investigate the occurrence of oil spill in Malaysian coastal waters using ENVISAT ASAR satellite data. The study shows that crossover process, and the fitness function generated accurate pattern of oil slick in SAR data. This shown by 85% for oil spill, 5% look-alike and 10% for sea roughness using the receiver -operational characteristics (ROC) curve. It can therefore be concludedcrossover process, and the fitness function have the main role in genetic algorithm achievement for oil spill automatic detection in ENVISAT ASAR data. © 2013 Springer-Verlag Berlin Heidelberg.

Ahmad J.,University Technology of MARA | Yusoff N.I.M.,National University of Malaysia | Hainin M.R.,University of Technology Malaysia | Rahman M.Y.A.,University Technology of MARA | Hossain M.,Kansas State University
Construction and Building Materials | Year: 2014

A major concern for highway industries in tropical climatic countries is the excessive moisture-induced damage to hot-mix asphalt (HMA) pavements as a result of frequent passes by heavy axle loads. Therefore, in this study, two different approaches, the Superpave and Marshall mix design methods, were used to design HMA mixes and a comparison was made to identify how susceptible these mixtures are to moisture damage. The Modified Lottman test and Simple Performance Test (SPT) were performed on unconditioned and conditioned specimens tailored to suit tropical climatic conditions, omitting freeze and thaw. The Modified Lottman test showed that the tensile strength values of Superpave-designed mixtures are higher than Marshall-designed mixtures. The tensile strength ratio (TSR) values decreased from unconditioned to conditioned specimens, suggesting that there is damage to the mixtures. The results also show good agreement between the TSR and ESR in the two tests, with a coefficient of determination value of 0.78. This relationship indicates that the SPT dynamic modulus test was effective and suitable to evaluate the lab-measured moisture susceptibility of HMA mixes. Since the dynamic modulus test provides a full characterisation of the mix over a broad range of temperatures and loading frequencies, this test is highly recommended for Superpave mixture characterisation in tropical climatic conditions. © 2013 Elsevier Ltd. All rights reserved.

Abdullah M.R.,University of Technology Malaysia | Prawoto Y.,Surya University | Cantwell W.J.,KhalifaUniversity of Science | Cantwell W.J.,University of Liverpool
Materials and Design | Year: 2015

As the adhesion quality plays an important role in determining the mechanical performance and environmental stability of most types of fibre-metal laminates (FMLs), investigating the interfacial fracture properties becomes one of the key factors for the improvement. Adhesion of a self-reinforced polypropylene (SRPP) and glass fibre reinforced polypropylene (GFPP) based FML is evaluated experimentally. Single Cantilever Beam (SCB) tests were performed to access interfacial fracture energy (G. c) of the bi-material laminates and their associated interlayer materials. Simulations mimicking the experiments were also performed. The energy needed to fracture was obtained experimentally and also via stress intensity factor from the simulations. The test results show that good adhesion between the aluminium and fibre reinforced thermoplastics can be achieved using a sulphuric acid anodising surface pre-treatment. Further examination has shown that the edges of the test samples highlighted the presence of significant fibre bridging in the SRPP and plastics deformation in the GFPP. © 2014 Elsevier Ltd.

Despite extensive research on service quality and its consequences, there is still a lack of empirical research examining these variables in the context of resort hotels. In filling the gap, this study aims to assess service quality as determinant of customer satisfaction and resulting behavioural intentions in the context of Malaysian resort hotels. Based on the literature review, this study validates a new operationalization of service quality and hypothesises its significant effects on customer satisfaction and behavioural intentions. Based on convenience sampling, 425 questionnaires were received from the guests of Malaysian resort hotels. Structural equation modelling was used to analyse the collected data and the findings point out that, in general, guests were satisfied with the quality of the services provided by Malaysian resort hotels. It is also revealed that better perceptions of hotel ambience and staff courtesy, food and beverage products, staff performance and knowledge, reservation services and financial value were more likely to develop customer satisfaction which was, in turn, more likely to result in positive behavioural intentions such as revisit intentions or intentions to recommend it to others. The implications of these findings, limitation of the study and future research suggestions are also discussed.

Selamat A.,University of Technology Malaysia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Language identification has been widely used for machine translations and information retrieval. In this paper, an improved N-grams (ING) approach is proposed for web page language identification. The improved N-grams approach is based on a combination of original N-grams (ONG) approach and a modified N-grams (MNG) approach that has been used for language identification of web documents. The features selected from the improved N-grams approach are based on N-grams frequency and N-grams position. The features selected from the original N-grams approach are based on a distance measurement and the features selected from the modified N-grams approach are based on a Boolean matching rate for language identification of Roman and Arabic scripts web pages. A large real-world document collection from British Broadcasting Corporation (BBC) website, which is composed of 1000 documents on each of the languages (e.g., Azeri, English, Indonesian, Serbian, Somali, Spanish, Turkish, Vietnamese, Arabic, Persian, Urdu, Pashto) have been used for evaluations. The precision, recall and F1 measures have been used to determine the effectiveness of the proposed improved N-grams (ING) approach. From the experiments, we have found that the improved N-grams approach has been able to improve the language identification of the contents in Roman and Arabic scripts web page documents from the available datasets. © 2011 Springer-Verlag Berlin Heidelberg.

Woldeyohannes A.D.,University of Technology Malaysia | Majid M.A.A.,Petronas University of Technology
Simulation Modelling Practice and Theory | Year: 2011

This paper focuses on developing a simulation model for the analysis of transmission pipeline network system (TPNS) with detailed characteristics of compressor stations. Compressor station is the key element in the TPNS since it provides energy to keep the gas moving. The simulation model is used to create a system that simulates TPNS with different configurations to get pressure and flow parameters. The mathematical formulations for the TPNS simulation were derived from the principles of flow of fluid through pipe, mass balance and compressor characteristics. In order to determine the unknown pressure and flow parameters, a visual C++ code was developed based on Newton-Raphson solution technique. Using the parameters obtained, the model evaluates the energy consumption for various configurations in order to guide for the selection of optimal TPNS. Results from the evaluations of the model with the existing TPNS and comparison with the existing approaches showed that the developed simulation model enabled to determine the operational parameters with less than 10 iterations. Hence, the simulation model could assist in decisions regarding the design and operations of the TPNS. © 2010 Elsevier B.V. All rights reserved.

Ramli M.Z.,University Technical Malaysia Melaka | Salam Z.,University of Technology Malaysia
IEEE Transactions on Power Electronics | Year: 2014

This paper proposes a simple circuit to recover the energy that otherwise would be lost due to the partial shadings on photovoltaic (PV) modules. Since the circuit can be readily retrofitted to an existing PV system, no modification on the central inverter is required. The main idea of the scheme is that, during partial shading, parts of the current from the nonshaded modules are harvested by an energy recovery circuit using power electronic switches and storage components. In doing so, the current of the PV string is maintained at the level generated by the shaded module. There is no need for the shaded module to be short-circuited; as a result, it can still actively produce output power (despite being partially shaded). To investigate the idea, the proposed circuit is retrofitted to a prototype PV system using eight modules. The partial shading conditions are emulated using a solar simulator with a controllable irradiance capability. The results are validated by a good agreement between the experimental and simulation works. © 2014 IEEE.

Marghany M.,University of Technology Malaysia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

The paper is focused on three-dimensional (3-D) coastline deformation from interferometry synthetic aperture radar (InSAR). In doing so, conventional InSAR procedures are implemented to three repeat passes of ENVISAT ASAR data. Further, three-dimensional sorting reliabilities algorithm (3D-SRA) is implemented with phase unwrapping technique. Consequently, the 3D-SRA is used to eliminate the phase decorrelation impact from the interferograms. The study shows the performance of InSAR method using the 3D-SRA is better than InSAR procedure which is validated by a lower range of error (0.06±0.32 m) with 90% confidence intervals. In conclusion, integration of the 3D-SRA with phase unwrapping produce accurate 3-D coastline deformation. © 2013 Springer-Verlag Berlin Heidelberg.

Uddin M.J.,Bangladesh American International University | Khan W.A.,National University of Sciences and Technology | Amin N.S.,University of Technology Malaysia
PLoS ONE | Year: 2014

The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results. © 2014 Uddin et al.

Jaafar M.N.M.,University of Technology Malaysia | Ishak M.S.A.,University Malaysia Perlis | Saharin S.,International Islamic University Malaysia
Environmental Science and Technology | Year: 2010

This paper presents the development of an emissions-controlling technique for oil burners aimed especially to reduce oxides of nitrogen (NOx). Another emission of interest is carbon monoxide (CO). In this research, a liquid fuel burner is used. In the first part, five different radial air swirler blade angles, 30°, 40°, 45°, 50°, and 60°, respectively, have been investigated using a combustor with 163 mm inside diameter and 280 mm length. Tests were conducted using kerosene as fuel. Fuel was injected at the back plate of the swirler outlet. The swirler blade angles and equivalence ratios were varied. A NOx reduction of more than 28% and CO emissions reduction of more than 40% were achieved for blade angle of 60° compared to the 30° blade angle. The second part of this paper presents the insertion of an orifice plate at the exit plane of the air swirler outlet. Three different orifice plate diameters of 35, 40, and 45 mm were used with a 45° radial air swirler vane angle. The fuel flow rates and orifice plate's sizes were varied. NOx reduction of more than 30% and CO emissions reduction of more than 25% were obtained using the 25 mm diameter orifice plate compared to the test configuration without the orifice plate. The last part of this paper presents tests conducted using the air-staging method. An industrial oil burner system was investigated using the air staging method in order to reduce emission, especially NOx. Emissions reduction of 30% and 16.7% were obtained for NOx and CO emissions, respectively, when using air staging compared to the non-air-staging tests. © 2010 American Chemical Society.

Juang L.-H.,University of Technology Malaysia
Measurement: Journal of the International Measurement Confederation | Year: 2010

In this paper, a three-dimension (3-D) mechanical element with an extra electrical degree of freedom is employed to simulate the dynamic vibration modes of the linear piezoelectric, piezoelectro-mechanic and mechanical behaviors of a metal disc structure embedded with a piezoelectric actuator. In piezoelectric finite element formulation, a discretized equation of motion is developed and solved by using the integration scheme to explain why an adaptive boundary condition, a simple support condition with three non-equal-triangular (120°-90°-150°) fixed points near the edge, which is the asymmetric disc used as the stator of the studied ultrasonic motor, for the mechanical design of an asymmetric disc-type piezoelectric ultrasonic stator, is defined so that a lateral elliptical motion of the contact point between stator and rotor can be realized for driving the rotor. It starts from hybrid elements with displacement and electric potential as the nodal d.o.f.s model and uses Guyan reduction and Householder-Bisection inverse iteration to find the displacement profile and displacement vector flow of the stator under frequency driving. The standing wave existence is also proven by the displacement patterns of the finite element theoretical model. © 2010 Elsevier Ltd. All rights reserved.

Juang L.-H.,University of Technology Malaysia | Wu M.-N.,National Taichung Institute of Technology
Measurement: Journal of the International Measurement Confederation | Year: 2010

We present a preliminary design and experimental results of a Gaussian noise reduction method for ultrasound images. Our method utilizes a Wiener filtering algorithm with pseudo-inverse technique. The method is capable of solving the Gaussian noise problem in ultrasound image by setup a constant dB of noise function. The key idea of the Wiener filtering algorithm is to process the given ultrasound signal by making the filtering less sensitive to slight changes in input conditions. In this paper, we investigate the possibility of employing this approach for pre-processing ultrasound image application. The application of the proposed method for reducing Gaussian noise is demonstrated by four examples. Meanwhile, we also made the comparisons with median filter, mean filter and adaptive filter; the results reveal that the proposed method has the best noise filtering capability than other three methods. The results also show that the proposed method produces recovery images with quiet high peak-signal-to-noise ratio. © 2010 Elsevier Ltd. All rights reserved.

Kaczorek T.,University of Technology Malaysia
Archives of Electrical Engineering | Year: 2013

Necessary and sufficient conditions for the reachability and observability of the positive electrical circuits composed of resistors, coils, condensators and voltage sources are established. Definitions of the input-decoupling zeros, output-decoupling zeros and input-output decoupling zeros of the positive electrical circuits are proposed. Some properties of the decoupling zeros of positive electrical circuits are discussed.

Pohl C.,University of Technology Malaysia | van Genderen J.,University of Twente
International Journal of Image and Data Fusion | Year: 2015

The exploitation of multi-sensor images at pixel level is a widely implemented research field in Earth observation. In this context, image fusion plays an important role since it effectively combines complementary image content to enhance information contained in the individual datasets. This article presents an overview of the existing fusion techniques and their achievements for Earth scientists. This research started off with the compilation of a database on remote sensing image fusion journal publications. Research results were exploited, grouping the literature into different aspects of relevance. Six categories of information have been built according to the journal, the application, sensors that provided the images used in the case study, applied fusion techniques, areas of achievement, and on-going research highlighting unresolved questions and current science. This resulted in an overview on the categorisation of image fusion techniques, explanation of the various approaches used within a certain category, and description of particularities when dealing with the fusion of optical and radar imagery. Even though many researchers intend to find the best algorithm, there is a greater need to define an appropriate workflow prior to processing the imagery with the knowledge in all related fields, that is, remote sensing image fusion and the desired application to address the different aspects of error propagation. © 2015, © 2015 Taylor & Francis.

Mahdi Ziaei S.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2015

The financial crisis is considered a major economic issue and energy consumption and pollution are believed to be one of the most important environmental concerns in the new millennium. The review on investigation of the nexus among energy consumption, GDP growth, financial development and CO2 emission has shown no definitive conclusion. Apart from that, the effects of financial development on energy consumption are not yet understood properly. Thus, this article investigates the effects of financial indicator shocks i.e. credit market and stock market shocks on energy consumption and carbon dioxide (CO2 emissions) and vice versa. Panel Vector Auto Regression (PVAR) models were employed to investigate the relationships in 13 European and 12 East Asia and Oceania countries from 1989 to 2011. Findings emphasize the important role of CO2 emission and energy consumption on explaining each other's deviation, with only the degree of effect differing. Although energy consumption and CO2 emission shocks on financial indicators such as private sector credit is not very pronounced in both groups of countries, but the strength of energy consumption shock on stock return rate in European countries is greater than East Asian and Oceania countries. Conversely shocks to stock return rate influence energy consumption especially in long horizon in case of East Asia and Oceania countries. © 2014 Elsevier Ltd.

Woldemichael D.E.,University of Technology Malaysia | Hashim F.M.,Petronas University of Technology
Journal of Engineering, Design and Technology | Year: 2011

Purpose: The purpose of this paper is to describe the framework of conceptual design support tool (CDST) developed to assist designers during conceptual design process. The premise of the study is that, by combining human creativity with computer capabilities, it is possible to perform conceptual design process more efficiently than solely manual design. The study aims to show how conceptual design knowledge can be captured from experienced designers and kept in the computer system for later use and how the developed tool assists designers by handling some of the repetitive and time-consuming tasks. Design/methodology/approach: A conceptual design process model, which integrates systematic design approach with knowledge-based system, is proposed. Based on this model, a CDST, which consists of function library, alternative concepts database, different modules for conceptual design activities, and a knowledge-based system is developed. The alternative concepts database is built based on design reuse philosophy. Furthermore, the tool is designed to accept and save new concepts from the user through its knowledge acquisition module without modifying the source code. The CDST is developed using public domain open source programming environments namely CLIPS, Python, wxPython, and PyCLIPS. Findings: Through its graphical user interface, CDST assists designers in performing the conceptual design process such as functional modelling, using standard vocabularies of functions, generating concepts and displaying on morphology chart, concept combination, and concept evaluation. The functionality and interaction between the user and the CDST is demonstrated with an example. Research limitations/implications: Currently, the alternative concepts database consists of concepts from subsea process equipment design and few general mechanical designs. The database can be enhanced by adding more concepts through the knowledge acquisition module provided. Practical implications: The tool can be used as a knowledge management system in industry by capturing expertise knowledge and to train novice designers. It augments designer's knowledge by providing concepts from past designs. Originality/value: The research output from this paper can be valuable resource in industry to support designers with computers. The research represents one of the attempts to develop domain independent conceptual design tool that can acquire new concepts throughout its lifetime. © Emerald Group Publishing Limited.

Sidik N.A.C.,University of Technology Malaysia | Mamat R.,Universiti Malaysia Pahang
International Communications in Heat and Mass Transfer | Year: 2015

Researches on nanofluids have been quite intensive in the past decade. The performances of nanofluids have been experimentally and theoretically investigated by various researchers across the world. Among the proposed numerical methods, the lattice Boltzmann method has been shown to predict the heat transfer augmentation by nanofluids at acceptable accuracy. In this review, we summarize the recent progress of lattice Boltzmann formulation in predicting nanofluids and try to find some challenging issues that need to be solved for future research. © 2015 Elsevier Ltd.

Bahari S.F.,University of Technology Malaysia | Clarke S.,University of Manchester
Journal of Safety Research | Year: 2013

Problem: Whilst substantial research has investigated the nature of safety climate, and its importance as a leading indicator of organisational safety, much of this research has been conducted with Western industrial samples. The current study focuses on the cross-validation of a safety climate model in the non-Western industrial context of Malaysian manufacturing. Method: The first-order factorial validity of Cheyne et al.'s (1998) [Cheyne, A., Cox, S., Oliver, A., Tomas, J.M., 1998. Modelling safety climate in the prediction of levels of safety activity. Work and Stress, 12(3), 255-271] model was tested, using confirmatory factor analysis, in a Malaysian sample. Results: Results showed that the model fit indices were below accepted levels, indicating that the original Cheyne et al. (1998) safety climate model was not supported. An alternative three-factor model was developed using exploratory factor analysis. Discussion: Although these findings are not consistent with previously reported cross-validation studies, we argue that previous studies have focused on validation across Western samples, and that the current study demonstrates the need to take account of cultural factors in the development of safety climate models intended for use in non-Western contexts. Impact on industry: The results have important implications for the transferability of existing safety climate models across cultures (for example, in global organisations) and highlight the need for future research to examine cross-cultural issues in relation to safety climate. © 2013 National Safety Council and Elsevier Ltd.

Juang L.-H.,University of Technology Malaysia | Wu M.-N.,National Taichung Institute of Technology
Measurement: Journal of the International Measurement Confederation | Year: 2010

We present a preliminary design and experimental results of tumor objects tracking method for magnetic resonance imaging (MRI) brain images (some stock images) that utilizes color-converted segmentation algorithm with K-means clustering technique. The method is capable of solving unable exactly contoured lesion objects problem in MRI image by adding the color-based segmentation operation. The key idea of color-converted segmentation algorithm with K-means is to solve the given MRI image by converting the input gray-level image into a color space image and operating the image labeled by cluster index. In this paper we investigate the possibility of employing this approach for image-based-MRI application. The application of the proposed method for tracking tumor is demonstrated to help pathologists distinguish exactly lesion size and region. © 2010 Elsevier Ltd. All rights reserved.

Adrus N.,University of Duisburg - Essen | Adrus N.,University of Technology Malaysia | Ulbricht M.,University of Duisburg - Essen
Journal of Materials Chemistry | Year: 2012

Hydrogel pore-filled composite membranes (HPFCM) based on polyethylene terephthalate (PET) track-etched membranes with pore diameters between 200 and 5000 nm and temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels were successfully prepared. A premodification of the pore walls by grafted linear PNIPAAm led to stable anchoring of crosslinked PNIPAAm prepared in a subsequent step. Proper tuning of photopolymerization conditions resulted in a desired microstructure of the hydrogels and thus tailored barrier properties of the composite membranes. The very interesting separation performance of HPFCM was due to diversification of the hydrogel network that caused adjustable sieving properties via synthesis conditions and also largely switchable barrier properties in response to the temperature. The interplay between the immobilized hydrogel and various pore sizes of the membrane support was also investigated. The base membrane provides mechanical support and confines the hydrogel within its pores, and it thus allows using the hydrogel mesh size for size-selective solute transport. Completely stable and selective HPFCM were only obtained with base pore sizes of about 2 μm or smaller. The size-selectivity (molecular weight cut-off) of the same HPFCM was higher under diffusive than under convective flow conditions; this is presumably mainly caused by elasticity deformation of the hydrogel network. The apparent cut-off from diffusion experiments was well correlated to the mesh-size of the hydrogel determined from the Darcy model applied to permeability data obtained under convective flow conditions. Upon temperature increase beyond 32 °C, flux increased and rejection decreased very strongly; this remarkable change between macromolecule-size selective ultrafiltration and microfiltration/filtration behavior was fully reversible. © 2012 The Royal Society of Chemistry.

Chong C.T.,University of Cambridge | Chong C.T.,University of Technology Malaysia | Hochgreb S.,University of Cambridge
Combustion and Flame | Year: 2011

The effect of acetone on the laminar flame speed of methane/air mixtures is investigated over a range of stoichiometries at atmospheric pressure and room temperature. The liquid acetone is vaporised and seeded into the methane/air mixture at 5%, 9% and 20% of the total fuel by mole. The experiment is performed using the jet-wall stagnation flame configuration and the particle imaging velocimetry (PIV) technique. Laminar flame speeds are derived by extrapolating the reference flame speed back to zero strain rate. Experimental results are compared to numerically calculated values using a base methane chemical kinetic mechanism (GRI-Mech 3.0) extended with acetone oxidation and pyrolysis reactions from the literature. The experimental results show that acetone addition does not affect the laminar flame speed of methane significantly within the range of concentrations considered, with a stronger effect on the rich range than under fuel-lean conditions, and that the peak laminar flame speed of acetone in air is ∼42.5cm/s at φ=1.2. Simulation results reveal that the most important reactions determining acetone laminar flame speeds are H+O2→O+OH, OH+CO→H+CO2, HO2+CH3→OH+CH3O and H+O2+H2O→HO2+H2O. Comparison of the expected disappearance of acetone relative to methane shows that the former is a good fluorescent marker for the latter. © 2010 The Combustion Institute.

Juang L.-H.,University of Technology Malaysia
Measurement: Journal of the International Measurement Confederation | Year: 2010

A Radon transform algorithm which incorporates the correlated X-ray images (some stock chest radiographs) into the processing of back-projection with the fan-beam geometry reconstruction with the aim of improving image quality was developed and explored. These reconstruction images were evaluated and compared with the original image. Meanwhile, we also made the comparisons with the filtered back-projection method and the Radon transform method without fan-beam geometry; the results also reveal that the proposed method has the best image reconstruction capability than other two methods. The results show that the proposed method produces reconstructed images with quiet high peak-signal-to-noise ratio. © 2009 Elsevier Ltd. All rights reserved.

Ng R.T.L.,University of Technology Malaysia | Ng D.K.S.,University of Nottingham Malaysia Campus | Tan R.R.,De La Salle University - Manila
Journal of Cleaner Production | Year: 2015

In this paper, a systematic approach for synthesising and optimising a symbiotic bioenergy park is presented. A novel stability analysis criterion of the symbiotic bioenergy park is developed based on the concept of incremental investment return analysis. The synthesised symbiotic bioenergy park is stable as long as no partner bears a disproportionate share of additional investment costs relative to benefits gained from cooperation. In case the symbiotic bioenergy park is not stable, re-evaluation (e.g., additional incentives from government, subsidies from high profit companies, etc.) can be conducted amongst all participants. In this work, fuzzy optimisation is adapted to trade-off individual economic interest and stability of each processing plant. The optimised network configuration which achieves the targets with minimum biomass value losses can be determined prior to detailed design. A palm-based symbiotic bioenergy park case study is solved to illustrate the proposed approach. © 2014 Elsevier Ltd. All rights reserved.

A new species of the rare neritopsid gastropod genus Magnicapitatus is documented from a fusulinoid-rich limestone of the Khao Taa Ngog Formation (Capitanian, Middle Permian) at Khao Makha in East Thailand near the Cambodian border (in the Indochina Terrane). This represents the first record of this Permo-Triassic genus outside South China and from the Capitanian. Magnicapitatus is one of the typical molluscan lazarus taxa that apparently disappeared at the end of the Permian but reappeared after the Early Triassic. © 2010 Association of Australasian Palaeontologists.

Adrus N.,University of Duisburg - Essen | Adrus N.,University of Technology Malaysia | Ulbricht M.,University of Duisburg - Essen
Reactive and Functional Polymers | Year: 2013

Bulk poly(N-isopropylacrylamide) hydrogels were prepared via free radical polymerization. Two different initiation methods were studied: redox- and photoinitiation. It was demonstrated that the desired final properties of resulting hydrogels, i.e., high monomer conversion (>95%) and adjustable swelling were only obtained by selecting best suited initiation conditions. For redox polymerization, this was achieved by tuning the ratio of accelerator N,N,N′,N′-tetramethylethylenediamine to initiator ammonium persulfate. The key parameters for achieving optimum photopolymerization conditions were photoinitiator concentration and UV irradiation time. With help of in situ rheological measurements, optimum conditions could be further verified and quantified by monitoring the liquid-to-gel transition. Overall, photoiniated crosslinking copolymerization was postulated to offer better options for in situ preparation of tailored functional hydrogels, in particular for the integration of smart soft matrices within membrane pores or other microsystems via a rapid reaction. Rheology was also used to investigate the hydrogel after ex situ preparation, revealing "perfect" soft-rubbery behavior. A good correlation between the mesh sizes determined from swelling and rheology was also found. In conclusion, rheology has been found to be a powerful tool because it provides valuable data on polymerization and gelation kinetics as well as information about the hydrogels microstructure based on their viscoelastic character. © 2012 Elsevier Ltd. All rights reserved.

This paper presents an acoustic noise canceling technique using an inverse kepstrum system as an innovations-based whitening application for an adaptive finite impulse response (FIR) filter in beamforming structure. The inverse kepstrum method uses an innovations-whitened form from one acoustic path transfer function between a reference microphone sensor and a noise source so that the rear-end reference signal will then be a whitened sequence to a cascaded adaptive FIR filter in the beamforming structure. By using an inverse kepstrum filter as a whitening filter with the use of a delay filter, the cascaded adaptive FIR filter estimates only the numerator of the polynomial part from the ratio of overall combined transfer functions. The test results have shown that the adaptive FIR filter is more effective in beamforming structure than an adaptive noise canceling (ANC) structure in terms of signal distortion in the desired signal and noise reduction in noise with nonminimum phase components. In addition, the inverse kepstrum method shows almost the same convergence level in estimate of noise statistics with the use of a smaller amount of adaptive FIR filter weights than the kepstrum method, hence it could provide better computational simplicity in processing. Furthermore, the rear-end inverse kepstrum method in beamforming structure has shown less signal distortion in the desired signal than the front-end kepstrum method and the front-end inverse kepstrum method in beamforming structure. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Nair A.K.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Kumar R.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia
Desalination | Year: 2013

Calcium carbonate nanoparticles were synthesized from calcium nitrate via chemical precipitation method. The nanoparticles were characterized using scanning electron microscope (SEM), Attenuated total reflectance infra red (ATR-IR) spectrum and by X-ray diffraction (XRD). These nanoparticles were used as additive for polysulfone (PSf) ultrafiltration membrane along with polyethylene glycol (PEG) as pore forming agent. The PSf hybrid membranes were characterized by ATR-IR, XRD, and SEM studies. ATR-IR and XRD results indicated the successful incorporation of the nanoparticles in the membranes. Cross sectional images of the membranes along with the elemental mapping of calcium on the membrane surface were assessed using SEM. Hydrophilicity of the membranes was evaluated in terms of contact angle measurements. The permeability of the membranes was determined by measuring the pure water flux (PWF). Membranes were also subjected to antifouling studies using bovine serum albumin (BSA) as the standard protein for rejection. The membranes showed better permeability and antifouling property with the increased addition of CaCO3 nanoparticles. © 2013 Elsevier B.V.

Kumar R.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka | Ismail A.F.,University of Technology Malaysia | Matsuura T.,University of Ottawa
Journal of Membrane Science | Year: 2013

A novel water soluble Chitosan derivative N-propylphosphonic Chitosan (NPPCS) having a terminal phosphonic acid group was synthesized by reacting Chitosan with Hydroxybenzotriazole (HOBt) and propylphosphonic anhydride (T3P)® via one pot reaction. The novel derivative was characterized by 1H NMR, Attenuated Total Reflectance Infra Red (ATR-IR) spectroscopy and XRD. Due to insolubility of NPPCS in organic solvents, a new process was demonstrated for blending of NPPCS with Polysulfone. The proper blending of NPPCS with Polysulfone was confirmed by ATR-IR spectroscopy. The improved hydrophilicity of PSf/NPPCS membranes was confirmed by contact angle measurement. The permeation studies showed increased flux of PSf/NPPCS membranes as compared to the pristine Polysulfone membrane. The antifouling property of PSf/NPPCS membrane was determined by Bovine Serum Albumin (BSA) protein rejection studies. The membranes showed the enhanced antifouling property as compared to pristine Polysulfone membranes with a maximum of 74% flux recovery ratio (FRR) value. © 2013 Elsevier B.V.

Zaini M.A.A.,Chiba University | Zaini M.A.A.,University of Technology Malaysia | Amano Y.,Chiba University | Machida M.,Chiba University
Journal of Hazardous Materials | Year: 2010

The aim of this research is to produce activated carbons derived from polyacrylonitrile (PAN) fiber and to examine their feasibility of removing heavy metals from aqueous solution. Thermogravimetric analysis was used to identify the suitable conditions for preparing oxidized fiber and coke as activated carbon precursors. Steam and CO2 were used to activate the precursors. Activated carbons were characterized by their pore texture, elemental compositions and surface functionalities. Batch adsorption and desorption studies were carried out to determine the metal-binding ability of activated carbons. Two commercial activated carbon fibers (ACFs), i.e., A-20 and W10-W, were employed to compare the removal performance of PAN derived activated carbons. Influence of oxidation treatment of PAN fiber prior to steam activation was also explored and discussed. Results indicated that steam produced a higher surface area but a lower resultant yield as compared to CO2. Also, precursors activated by steam showed a greater removal performance. For both activation methods, fiber displayed a better metal-binding ability than coke. A small nitrogen loss from PAN fiber as a result of oxidation treatment assisted a greater removal of Cu(II) and Pb(II), but the interaction to Cu(II) was found stronger. It is proposed that the formation of cyclized structure by oxidation treatment minimized the nitrogen loss during steam activation, hence increased the uptake performance. © 2010 Elsevier B.V.

Marghany M.,University of Technology Malaysia
European Journal of Scientific Research | Year: 2010

In this study, we investigate the relative ability of least square algorithm to retrieve sea surface salinity (SSS) from MODIS satellite data. We also examine with comprehensive comparison of the root mean square of bias the difference between second polynomial order algorithm and least square algorithm. Both the least squares and algorithm second polynomial order algorithm are used to retrieve the sea surface salinity (SSS) from multi MODIS bands data. Thus, the basic linear model has been solved by using second polynomial order algorithm and least square estimators. The accuracy of this work has been examined using the root mean square of bias of sea surface salinity retrieved from MODIS satellite data and the in situ measurements that are collected along the east coast of peninsular Malaysia by using hydrolab instrument. The study shows comprehensive relationship between least square method and in situ SSS measurements with high r2 of 0.96 and RMS of bias value of ±0.37 psu. The second polynomial order algorithm, however, has lower performance as compared to least square algorithm. Thus, RMS of bias value of ± 7.34 psu has performed with second polynomial order algorithm. In conclusions, the least square algorithm can be used to retrieve SSS from MODIS satellite data. © EuroJournals Publishing, Inc. 2010.

Lim Y.-W.,University of Technology Malaysia
International Journal of Sustainable Building Technology and Urban Development | Year: 2014

Terraced houses account for 44% of the existing urban residential buildings in Malaysia. However, these houses have very constrained use of natural ventilation and lighting due to openings with small window-to-floor ratio. The deep plan design causes gloomy indoor spaces, low air change rate and poor indoor air quality. Hence, the sustainability of these terraced houses in the tropical climate needs to be further investigated. Studies showed that indoor environments have a major impact on occupants' well-being. Thereby this paper looks into indoor thermal and visual performances as the means of sustainability and their impact on occupants' perceived comfort and health in Malaysian typical terraced houses. A survey of terraced houses in Johor Bahru, Malaysia, was conducted using a questionnaire. Various terraced houses were studied to identify the critical comfort and health issues in terraced housing. The relationships between occupants' perceived comfort, behaviour and health were studied. The variance of types of terraced house was also analysed. The findings demonstrated significant linear relationships among thermal comfort, visual comfort and health. However, occupants' behaviour did not have a significant impact on thermal comfort and health. This paper concludes that it is essential to improve indoor thermal and visual comfort in Malaysian typical terraced houses through sustainable design to enhance occupants' health. © 2014 © 2014 Taylor & Francis.

Ishak M.S.A.,University Malaysia Perlis | Jaafar M.N.M.,University of Technology Malaysia
International Review of Mechanical Engineering | Year: 2014

The main purpose of this paper is to study the internal flow effect of varying the swirl number inside the combustor. The flow field inside the combustor is controlled by the liner shape and size, wall side holes shape, size and arrangement (primary, secondary and dilution holes), and primary air swirler configuration. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. Four radial curve vane swirler with 30°, 40°, 50° and 60° vane angle corresponding to swirl number of 0.366, 0.630, 0.978 and 1.427 respectively were used in this analysis to show vane angle effect on the internal flow field. The flow behavior was investigated numerically using CFD solver Ansys 14.0. This study has provided the characteristic insight into the flow pattern inside the combustion chamber. Results show that the swirling action is augmented with the increase in the swirl number, which leads to increase in the turbulence strength, recirculation zone size, and amount of recirculated mass. The current study report that the 50° swirler (swirl number > 0.7), produced enough swirling flow to generate good CRZ in the combustion chamber. © 2014 Praise Worthy Prize S.r.l. - All rights reserved.

Hatami T.,Razi University | Meireles M.A.A.,University of Campinas | Zahedi G.,University of Technology Malaysia
Journal of Supercritical Fluids | Year: 2010

In the present study, a mathematical modeling for extraction of oil from clove buds using supercritical carbon dioxide was performed. Mass transfer is based on local equilibrium between solvent and solid. The model was solved numerically, and model estimation was validated using experimental data. For optimization, the clove oil equilibrium constant between solid and supercritical phase was determined by a theoretical method using fugacity concept, consequently the genetic algorithm for obtaining optimal operational conditions was used. The optimal conditions which obtained the highest amount of clove oil were pressure of 10 MPa and temperature of 304.2 K. © 2009 Elsevier B.V. All rights reserved.

Tiew B.J.,Petronas University of Technology | Shuhaimi M.,Petronas University of Technology | Hashim H.,University of Technology Malaysia
Applied Energy | Year: 2012

Carbon emission reduction targeting is an important and effective effort for industry to contribute in controlling greenhouse gases concentration in atmosphere. Graphical approach has been proposed for CO2 emissions reduction targeting via HEN retrofit and fuel switching. However, it involves potentially time consuming manual procedures and the quality of solutions produced greatly depends on designer's experience and judgment. Besides, graphical approach hardly account for the cost factor during the design phase, thus potentially generate complex design. This paper introduces an MINLP model for simultaneous CO2 emissions reduction targeting via fuel switching and HEN retrofit. A sequential model execution was proposed along with the proposed model. The application of the model on a crude preheat train case study has demonstrated its workability to generate optimal solution for targeted CO2 emissions reduction at minimum payback period. © 2011 Elsevier Ltd.

Atabaki M.M.,University of Technology Malaysia | Atabaki M.M.,University of Leeds
Journal of Nuclear Materials | Year: 2010

Microstructural evolution of the partial transient liquid phase diffusion bonded Zircaloy-4 and stainless steel 321 using an active Ti-base interlayer were studied at different temperatures. Additionally, simple analytical models were developed to predict the evolution of the interlayer and intermetallics during the bonding operation. Bonds were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. Precision measurement of the interlayer width was made as a function of the bonding temperature. The liquid film migration occurred as a result of chemical solubility differences between the stable and metastable phases. The formation and growth model of the intermetallic compounds at the interfaces of Zircaloy-4/Ti-base interlayer and stainless steel 321/Ti-base interlayer for controlling the bonding process was studied considering the diffusion kinetics and the thermodynamics. The evolution of the interlayer thickness indicated a good agreement between the calculation and experimental measurement. It was also demonstrated that the low isothermal solidification kinetic was not only due to the enrichment of the liquid phase with the base alloying elements such as Ti and Zr, but also the reduction of solid solubility limit of Cu in the base alloys contributed to the reduction of isothermal solidification kinetic. © 2010 Elsevier B.V. All rights reserved.

Nasir M.H.N.,University of Malaya | Sahibuddin S.,University of Technology Malaysia
Scientific Research and Essays | Year: 2011

Although there have been studies completed on the critical success factors of software projects, these studies all have been specific to one particular country. There has been no comprehensive study reporting on different project sizes in various domains and in multiple countries. We present our extensive literature survey of critical success factors that impact software projects. Forty-three articles from the years 1990 to 2010 were found to be significant contributions that could be analysed in order to develop a list of critical factors that specifically affect the success of software projects. The method of content analysis and frequency analysis was adopted. Twenty-six critical success factors were found to be related to software project success. We suggest that organisation or project manager is attentive to control the top five critical factors to drive towards project success since the percentage of frequency of occurrences for each is more than 50%. Also, it appears that non-technical factors (94%) dominated over technical factors (6%). In a result unique to our study compared with previous one, we found that the factors of clear and frozen requirements, realistic estimation of the schedule and budget, along with a competent project manager are the five most critical success factors of software projects. © 2011 Academic Journals.

Hassim M.H.,Aalto University | Hassim M.H.,University of Technology Malaysia | Hurme M.,Aalto University
Journal of Loss Prevention in the Process Industries | Year: 2010

Occupational health studies the interaction of work and health, especially the long-term effect of chemicals to health. In this paper an Inherent Occupational Health Index has been developed for assessing the health risks of process routes during process research and development stage. The method takes into account both the hazard from the chemicals present and the potential for the exposure of workers to the chemicals. The index can be used either for determining the level of inherent occupational health hazards or comparing alternative process routes for these risks. The method is tailored for the process research and development stage by including only such properties of chemicals and operating conditions of process, which are available already in this early stage. In the end of this paper the approach is demonstrated by comparing the inherent occupational healthiness of six methyl methacrylate process routes using three different types of index calculations; additive-type, average-type, and worst case-type. The study discloses that the average- and worst case-based approaches analyze the characteristics of a route better than the additive calculation, which is greatly affected by the number of steps in the route. A quantitative standard scale for the index is also developed to allow health level assessment of a single process. © 2009 Elsevier Ltd. All rights reserved.

Sharma S.,ITM University | Ghoshal S.K.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2015

Transportation of people and commodities being a socio-economic criterion needs clean energy and the demand is kept on increasing with modernization. Consequently, generation of a fuel with safer, efficient, economic and reasonably environmental friendly features is the key issue towards fulfilling such demands. Hydrogen seems to be an ideal synthetic energy carrier due to its lightweight, exclusive abundance and environmentally benign oxidation product (water). However, storage remains a big challenge. In this communication, recent developments in the production of hydrogen fuel, applications and storage together with the environmental impacts of hydrogen as energy carrier are emphasized. © 2014 Elsevier Ltd. All rights reserved.

Aroon M.A.,University of Tehran | Ismail A.F.,University of Technology Malaysia | Matsuura T.,University of Ottawa
Separation and Purification Technology | Year: 2013

In this paper, synthesized (raw) multi-walled carbon nanotubes (rMWCNTs) were functionalized with beta-cyclodextrin (bC) using Chen's soft cutting technique. Raw multi-walled carbon nanotubes (rMWCNTs) and beta-cyclodextrin functionalized multi-walled carbon nanotubes (bCfMWCNTs) were characterized by transmission electron microscope (TEM). Neat polyimide (PI) and polyimide/bCfMWCNTs mixed matrix membranes were fabricated by immersion precipitation method. Pure methane and carbon dioxide were used as test gases to measure the permeances of membrane samples. Thermal properties of membranes and MWCNTs were characterized by differential scanning calorimetery (DSC) and thermogravimetric analysis (TGA), respectively. The TEM results showed that beta-cyclodextrin cannot only attach to the inner and outer surface of the MWCNT walls but also fill the open-ended tips of the MWCNTs. TGA thermograms showed that bCfMWCNTs are thermally less stable than rMWCNTs due to the decomposition of beta-cyclodextrin layer, which occurred before the decomposition of rMWCNTs. According to the DSC experiment, the glass transition temperature (T g) increased as bCfMWCNTs increases in the polymer matrix. The increase in glass transition was attributed to good dispersion of the bCfMWCNTs in the polymer matrix as a result of improved attachment of bCfMWCNTs to the polymer segments. Separation properties and morphology (and distribution of bCfMWCNTs within the polymer matrix) of the fabricated membranes were analyzed by using permeation test and cross sectional FESEM micrographs respectively. Permeation test results revealed that the ideal CO2/CH4 selectivity increased considerably from neat polyimide membrane to polyimide/bCfMWCNTs mixed matrix membranes. Cross sectional FESEM results showed that well dispersed bCfMWCNTs within the polymer matrix are observable especially in case of PI/6 wt.% BFBM MMM. © 2013 Elsevier B.V. All rights reserved.

Farsangi E.N.,University of Technology Malaysia
Gazi University Journal of Science | Year: 2010

This paper presents a finite element analysis on 4 types of precast connections which are pinned, rigid, semi rigid and a new proposed connection. The stiffness of the new connection is obtained from the slope of the total load versus deflection graph in the elastic range. Then the seismic loading from El Centro earthquake modified with 0.15g and 0.5g were applied to the whole structure. From the analysis results, new connection has sufficient stiffness, strength and also higher ductility. Meanwhile, the whole structure analysis results showed that the new connection behaves as semi rigid connection. LUSAS and SAP2000 have been used for analysis.

Zin M.R.M.,University Technical Malaysia Melaka | Sidik N.A.C.,University of Technology Malaysia
International Review of Mechanical Engineering | Year: 2010

In this paper, the vorticity transport equation is solved to predict the fluid flow in a two-dimensional, shear driven cavity for a wide range of Reynolds numbers and aspect ratio. The advection term in the governing equation is discretised by the constraint interpolated profile method. First, the code is validated for a one-dimensional wave equation and then the results of the flow structure are presented. Several features of the flow, such as the dynamics of the central vortex, the formation of the corner vortices are predicted and compared with the previous findings from other researchers. We found that the vortices structures are significantly dependent on the value of the aspect ratio of the cavity and the dimensionless Reynolds numbers. The predicted results are also shown to be consistent with the experimental study. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.

Tasir Z.,University of Technology Malaysia | Pin O.C.,Malaysian Teacher Education Institution
Computers and Education | Year: 2012

A printed module should consist of media elements, namely text and pictures, which are self-instructional and could cater to the needs of the user. However, the typical platform of such visualization frequently overloads the limited working memory causing split attention and redundancy effects. The purpose of this study is to design and develop a printed self-instructional module based on Cognitive Load Theory in learning. Media elements are presented with minimal cognitive demands with an action- and task-oriented approach. Utilizing a modified Solomon Group design on 113 trainee teachers selected using purposive sampling, the effectiveness of the developed module was compared to the conventional module. Independent sample t-tests conducted to compare the time of completion in performance between the Control Group working on the conventional module and Group 2 working on the developed module show significant statistical differences in pre- and post-activities. Group 2 reported lower cognitive load scores on the rating scale and graphical plots using computational approach showed higher instructional efficiency. Thus, results show that trainees working on the developed printed module were able to perform faster and better with lower mental effort and had higher performance. © 2012 Elsevier Ltd. All rights reserved.

Abdullah I.,University of Malaysia, Terengganu | Amin N.,University of Technology Malaysia
Mathematical Methods in the Applied Sciences | Year: 2010

A nonlinear two-dimensional micropolar fluid model for blood flow in a tapered artery with a single stenosis is considered. This model takes into account blood rheology in which blood consists of microelements suspended in plasma. The classical Navier-Stokes theory is inadequate to describe the microrotations or particles' spin of such suspension in a viscous medium. The governing equations involving unsteady nonlinear partial differential equations are solved using a finite difference scheme. A quantitative analysis performed through numerical computation shows that the axial velocity profile and the flow rate decrease and the wall shear stress increases once the artery is narrower in the presence of the polar effect. Furthermore, the taper angle certainly bears the potential to influence the velocity and the flow characteristics to considerable extent. Copyright © 2010 John Wiley & Sons, Ltd.

Saiam Z.,University of Technology Malaysia
Journal of Power Electronics | Year: 2010

This paper proposes a new harmonic elimination PWM (HEPWM) scheme for voltage source inverters (VSI) based on the curve fittings of certain polynomials functions. The resulting equations to calculate the switching angle of the HEPWM require only the addition and multiplication processes; therefore any number of harmonics to be eliminated and the fundamental amplitude of the pole switching waveform (NP1) can be controlled on-line. An extensive angle error analysis is carried out to determine the accuracy of the algorithm in comparison to the exact solution. To verify the workability of the technique, an experimental single phase VSI is constructed. The algorithm is implemented on a VSI using a 16-bit microprocessor. The results obtained from the test rig are compared to the theoretical prediction and the results of the MATLAB simulations.

Masood I.,University Tun Hussein Onn Malaysia | Hassan A.,University of Technology Malaysia
European Journal of Scientific Research | Year: 2010

Control chart pattern recognition has become an active area of research since late 1980s. Much progress has been made, in which there are trends to heighten the performance of artificial neural network (ANN)-based control chart pattern recognition schemes through feature-based and wavelet-denoise input representation techniques, and through modular and integrated recognizer designs. There is also a trend to enhance it's capability for monitoring and diagnosing multivariate process shifts. However, there is a lack of literature providing a critical review on the issues associated to such advances. The purpose of this paper is to highlight research direction, as well as to present a summary of some updated issues in the development of ANN-based control chart pattern recognition schemes as being addressed by the frontiers in this area. The issues highlighted in this paper are highly related to input data and process patterns, input representation, recognizer design and training, and multivariate process monitoring and diagnosis. Such issues could be useful for new researchers as a starting point to facilitate further improvement in this area. © EuroJournals Publishing, Inc. 2010.

Kueh A.B.H.,University of Technology Malaysia
Composites Part A: Applied Science and Manufacturing | Year: 2014

Mechanical isotropy of triaxially woven fabric composite is investigated analytically, numerically using beam lattice models, and experimentally under tension and bending loads, due to evidence suggesting that its commonly regarded quasi-isotropy is shattered by size effects. Models verification has found that the sawtooth configuration best fits the observation. Employing therefore this configuration and varying model size, it is remarked that the mechanical behaviors are sensitive when loads are perpendicular to the tows direction while no obvious perturbation is seen when loads align with the tows. For practical convenience, time-saving universal equations that are mechanically meaningful are formulated, catering both loading directions for both pre- and post-straightening states for arbitrary size. © 2013 Elsevier Inc. All rights reserved.

Yong T.L.-K.,Hiroshima University | Yong T.L.-K.,University of Technology Malaysia | Matsumura Y.,Hiroshima University
Journal of Supercritical Fluids | Year: 2014

Decomposition of phenol and benzene was studied in supercritical water (SCW) at 370-450 C and 25 MPa over very short residence times (0.5-100 s). The study of simple model compounds such as phenol and benzene is an essential preliminary step to elucidate the primary mechanism of char and gas formation from lignin compounds. A quantitative detailed chemical kinetics model for the primary pathways of phenol and benzene decomposition in SCW was determined using the reaction pathways for its decomposition under supercritical conditions. The activation energy of benzene decomposition (91.16 kJ mol-1) in SCW is much higher than that of phenol (54.17 kJ mol-1) under similar experimental conditions. This emphasized the importance of the substituent group (hydroxyl group) in the benzene ring to enhance its decomposition rate. In addition, the reaction rate parameters, which are deduced for the overall reaction network of its decomposition under similar conditions, show good agreement with each another. Hence, the reaction rates of these reaction pathways are successfully described in this study. © 2014 Elsevier B.V.

Tolabi H.B.,Islamic Azad University | Moradi M.H.,Bu - Ali Sina University | Ayob S.B.M.,University of Technology Malaysia
International Journal of Energy Research | Year: 2014

This paper introduces a new classification scheme for the solar radiation estimation techniques based on three categories: empirical models (based on statistical regression techniques), simulated models (based on training), and optimized models (based on optimization algorithms). For the optimized model category, a novelty bees algorithm estimation based on a linear empirical model is developed. Eight different methods from three classes have been tested on three sample geographic positions of Iran in order to compare the efficiency, complexity, sensed parameters, and required prior training of each category with others by implementing in the Matlab software. Among all tested models, the best properties are obtained for optimized empirical models by optimization algorithms. The main advantages of this model type are that it eliminates the training stage and therefore reduces the complexity rather than simulated models yet offers high accuracy estimation. © 2014 John Wiley & Sons, Ltd.

Tan M.L.P.,University of Technology Malaysia
Journal of Nanomaterials | Year: 2013

Long channel carbon nanotube transistor (CNT) can be used to overcome the high electric field effects in nanoscale length silicon channel. When maximum electric field is reduced, the gate of a field-effect transistor (FET) is able to gain control of the channel at varying drain bias. The device performance of a zigzag CNTFET with the same unit area as a nanoscale silicon metal-oxide semiconductor field-effect transistor (MOSFET) channel is assessed qualitatively. The drain characteristic of CNTFET and MOSFET device models as well as fabricated CNTFET device are explored over a wide range of drain and gate biases. The results obtained show that long channel nanotubes can significantly reduce the drain-induced barrier lowering (DIBL) effects in silicon MOSFET while sustaining the same unit area at higher current density. © 2013 Michael Loong Peng Tan.

Zainal Abidin A.R.,University of Technology Malaysia | Zainal Abidin A.R.,Imperial College London | Izzuddin B.A.,Imperial College London
Engineering Structures | Year: 2013

In addition to typical perforated beams with regular openings of circular or hexagonal holes, the use of beams with irregular web holes of different shapes and arrangement is also widespread in steel construction. Despite some advantages over typical perforated beams, the behaviour of such beams is complicated by the irregularity of openings, which demands more reliable tools for assessing their local buckling response. This paper considers the efficient local buckling analysis of beams with regular and irregular web openings, employing the Element Free Galerkin (EFG) method for the numerical discretisation together with a simplified buckling assessment approach from the Rotational Spring Analogy (RSA). This combination offers a more effective means of buckling assessment utilising an iterative procedure of a rank 2 reduced eigenvalue problem along with a shifting local region. Several illustrative examples are provided to demonstrate the effectiveness of the proposed EFG/RSA approach for local buckling analysis of steel beams with irregular openings. © 2012 Elsevier Ltd.

Tahir M.,COMSATS Institute of Information Technology | Amin N.S.,University of Technology Malaysia
Applied Catalysis A: General | Year: 2013

In this study, a microchannel monolith photoreactor was investigated for photocatalytic CO2 reduction with H2O in gaseous phase using TiO2 and indium doped TiO2 nanoparticles. Effects of operating parameters such as monolith geometry, reaction temperature, indium loading and feed ratios were investigated to maximize yield rates. CO and CH4 were the main products with maximum yield rates being 962 and 55.40 μmol g-catal.-1 h-1, respectively and selectivity being 94.39 and 5.44%, respectively. The performance of the photoreactor for CO production was in the order of In/TiO2-monolith (962 μmol g-catal.-1 h-1) > TiO2-monolith (43 μmol g-catal.-1 h-1) > TiO2-SS cell (5.2 μmol g-catal.-1 h-1). More importantly, the quantum efficiency in microchannel monolith reactor was much higher (0.10%) than that of the cell type reactor (0.0005%) and previously reported internally illuminated monolith reactor (0.012%). The significantly