Johor Bahru, Malaysia
Johor Bahru, Malaysia

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.


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Alik R.,University of Technology Malaysia | Jusoh A.,University of Technology Malaysia
Solar Energy | Year: 2017

This paper proposes a modified maximum power point tracking (MPPT) technique for photovoltaic (PV) system using an improved Perturb and Observe (P&O) with a checking algorithm. The main advantage of this method is its simplicity and accuracy of the algorithm such that it can even be computed accurately using a low cost microcontroller. The basic idea of this modified P&O is adding a checking algorithm into a modified P&O MPPT. This checking algorithm functions to determine the global maximum power by comparing all existed peak points first, before the modified P&O algorithm takes place to identify the voltage at MPP (VMPP), which is needed to calculate the duty cycle for the boost converter. A simulation using MATLAB/Simulink under partial shading condition has been done to test the effectiveness of the algorithm. The simulation results are satisfactory and show that the improved technique is able to track the PV maximum power during partial shading condition with 100% of tracking efficiency and produce zero ripple at the load side. © 2017 Elsevier Ltd


Khalil A.M.,Assiut University | Hassan N.,University of Technology Malaysia
Journal of Intelligent and Fuzzy Systems | Year: 2017

The aim of this paper is to correct the assertions (3) and (4) of Theorem 3.23 proposed by Zhang and Shu [Journal of Intelligent and Fuzzy Systems 27 (2014) 2115-2125]. A counterexample illustrates the flaw of the assertions. We introduce the notion of generalized possibility multi-fuzzy soft sets and use it to correct the flaw in those assertions. Finally we introduce two new definitions and five theorems to improve the work of Zhang and Shu, along with two examples. © 2017 IOS Press and the authors. All rights reserved.


Shariff S.A.,University of Technology Malaysia | Abas H.,University of Technology Malaysia
Advanced Science Letters | Year: 2017

Learning English as a second language can be overwhelming for international students, especially when they are studying abroad and living in a foreign country. Some of the challenges include overcoming the anxiety to communicate with their peers and having assurance that they are being understood by others. The purpose of this phenomenological inquiry is to gather understandings about the international students’ experiences and essence of learning English conversational skills at the International Center’s English class. For this study, two international students were interviewed and three observations were conducted throughout the semester. Handouts and documents from the class were collected for further review and analysis. Based on the results from the interviews, observations, and document review, several categories were identified which included purpose, teacher’s role, motivation, preference, emotions, and problems. From those categories, two themes were emerged, (i) Interaction is important for learning English, and (ii) One needs to put much effort to learn English. © 2017 American Scientific Publishers All rights reserved.


Chaw J.-K.,University of Technology Malaysia | Mokji M.,University of Technology Malaysia
IET Image Processing | Year: 2017

Supermarkets nowadays are equipped with barcode scanners to speed up the checkout process. Nevertheless, most of the agricultural products cannot be pre-packaged and thus must be weighted. The development of produce recognition system based on computer vision could help the cashiers in the supermarkets with the pricing of these weighted products. This work proposes a hybrid approach of object classification and attribute classification for the produce recognition system which involves the cooperation and integration of statistical approaches and semantic models. The integration of attribute learning into the produce recognition system was proposed due to the fact that attribute learning has emerged as a promising paradigm for bridging the semantic gap and assisting in object recognition in many fields of study. This could tackle problems occurred when less training data are available, i.e. less than 10 samples per class. The experiments show that the correct classification rate of the hybrid approach were 60.55, 75.37 and 86.42% with 2, 4 and 8 training examples, respectively, which were higher than other individual classifiers. A well-balanced specificity, sensitivity and F1 score were achieved by the hybrid approach for each produce type. © The Institution of Engineering and Technology.


Mohd Kamal N.,University of Technology Malaysia | Wan Abu Bakar W.A.,University of Technology Malaysia | Ali R.,University of Technology Malaysia
Energy Conversion and Management | Year: 2017

Recently, there has been an increasing interest in green and renewable fuels due to the worldwide concern of an environmental crisis. So, this study focused on the synthesis, optimization and characterization of series of heterostructure Zn/Ca/Al2O3 catalysts with different parameters to test their effectiveness towards biodiesel production. The physicochemical properties of the potential catalyst were determined by BET, FESEM and CO2-TPD. The activity of the catalyst in transesterification reaction was evaluated at reaction temperature of 65 °C, 3 h reaction time, 6% (w/w) catalyst concentration and 1:24 M ratio of oil to methanol. The investigation of the synthesized Zn/Ca/Al2O3 catalyst showed that the calcination temperature, number of alumina coatings and dopant to base ratio have significant effects on the catalytic performance. These three critical parameters were investigated using response surface methodology (RSM) with Box Behnken design (BBD) to determine the optimum operating conditions for biodiesel production. From RSM study, the optimum conditions were 800 °C calcination temperature, 3 times alumina beads coating and 10:90 dopant to base ratio which gave 97.80% biodiesel conversion. From the F-value and low p-value (<0.05) obtained showed that the model was significant for predicting the optimum biodiesel conversion. An experiment was conducted under the optimum conditions to confirm the agreement of the model prediction and the experimental results. The experimental value (97.64%) closely agreed with the predicted results from RSM and hence validated the findings of response surface optimization. © 2017 Elsevier Ltd


Said M.,University of Technology Malaysia | Mat S.,University of Technology Malaysia
30th Congress of the International Council of the Aeronautical Sciences, ICAS 2016 | Year: 2016

This paper discusses the effects of Reynolds number on the passage of leading-edge vortex separation onset above blunt-edged delta wing VFE-2 configurations. The VFE-2 model differentiated by its leading edge radii namely medium and large-edged wings were fabricated and tested in UTM-Low Speed Wind Tunnel, (UTM-LST). The tests in this study were performed at speeds of 18, 36.1 and 54.2 m/s correspond to Reynolds numbers of 1×106, 2×106 and 3×106 based on the mean aerodynamic chord. The correlation between the leading-edge pressure coefficients on the onset of leading edge primary separation is discussed in this paper. The experimental results obtained from surface pressure measurements carried out on the upper surface of the model showed that higher Reynolds number can delay the formation of the primary vortex towards the aft portions of the wing.


Sabetian S.,University of Technology Malaysia | Shamsir M.S.,University of Technology Malaysia
Journal of Membrane Biology | Year: 2017

Complete elucidation of fertilization process at molecular level is one of the unresolved challenges in sexual reproduction studies, and understanding the molecular mechanism is crucial in overcoming difficulties in infertility and unsuccessful in vitro fertilization. Sperm–oocyte interaction is one of the most remarkable events in fertilization process, and deficiency in protein–protein interactions which mediate this interaction is a major cause of unexplained infertility. Due to detection of how the various defects of sperm–oocyte interaction can affect fertilization failure, different experimental methods have been applied. This review summarizes the current understanding of sperm–egg interaction mechanism during fertilization and also accumulates the different types of sperm–egg interaction abnormalities and their association with infertility. Several detection approaches regarding sperm–egg protein interactions and the associated defects are reviewed in this paper. © 2017 Springer Science+Business Media New York


Ng L.L.,University of Technology Malaysia | Chua H.S.,University of Technology Malaysia
ICCAS 2012 - 2012 IEEE International Conference on Circuits and Systems: "Advanced Circuits and Systems for Sustainability" | Year: 2012

This paper presents a novel event recognition framework in video surveillance system, particularly for parking lot environment. The proposed video surveillance system employs the adaptive Gaussian Mixture Model (GMM) and connected component analysis for background modeling and objects tracking. Spatial-temporal information of motion trajectories are extracted from video samples of known events to form representative feature vectors for event recognition purposes. An event is represented by feature vector that contains dynamic information of the motion trajectory and the contextual information of the tracked object. The event classification is accomplished by measuring the similarity of the extracted feature vector to the labeled definition of known events and analyzing the contextual information of the detected event. Experiments have been carried out on the live video stream captured by the outdoor camera, and the results have demonstrated great accuracy of the proposed event recognition algorithm. © 2012 IEEE.


Lai C.H.,University of Technology Malaysia | Wong W.,University of Technology Malaysia
ICCAS 2012 - 2012 IEEE International Conference on Circuits and Systems: "Advanced Circuits and Systems for Sustainability" | Year: 2012

A simulation on the dynamics of RF MEMS switch actuated using different tailored actuation voltage waveforms is presented. From the analysis, the contact velocity of the switch membrane is evaluated and compared. In order to eliminate bouncing, the approaching speed of the membrane should ideally be zero when contact is made, else the momentum of the high speed impact will bounce the membrane back and causing electrical discontinuities at the output signal. The effect of switch parameter variation on the bouncing is then studied by varying the parameter of the actuation voltages. Simulation and experimental results are then presented to corroborate the analytical findings. © 2012 IEEE.


Yousefpour A.,University of Technology Malaysia | Ibrahim R.,University of Technology Malaysia | Hamed H.N.A.,University of Technology Malaysia
Expert Systems with Applications | Year: 2017

Feature subset selection with the aim of reducing dependency of feature selection techniques and obtaining a high-quality minimal feature subset from a real-world domain is the main task of this research. For this end, firstly, two types of feature representation are presented for feature sets, namely unigram-based and part-of-speech based feature sets. Secondly, five methods of feature ranking are employed for creating feature vectors. Finally, we propose two methods for the integration feature vectors and feature subsets. An ordinal-based integration of different feature vectors (OIFV) is proposed in order to obtain a new feature vector. The new feature vector depends on the order of features in the old vectors. A frequency-based integration of different feature subsets (FIFS) with most effective features, which are obtained from a hybrid filter and wrapper methods in the feature selection task, is then proposed. In addition, four well-known text classification algorithms are employed as classifiers in the wrapper method for the selection of the feature subsets. A wide range of comparative experiments on five widely-used datasets in sentiment analysis were carried out. The experiments demonstrate that proposed methods can effectively improve the performance of sentiment classification. These results also show that proposed part-of-speech patterns are more effective in their classification accuracy compared to unigram-based features. © 2017 Elsevier Ltd


Lee Y.H.,University of Technology Malaysia | Tan C.S.,University of Technology Malaysia | Mohammad S.,University of Technology Malaysia
Thin-Walled Structures | Year: 2017

The use of light steel frames in rapid construction has grown significantly, especially concerning low and medium-rise buildings. However, there are limited resources available regarding the sway stiffness of light steel frames with flexible bolted joints. This paper presents a study on the lateral sway behaviour for light steel frames with bolted top-seat flange cleat connections comprising slender cold-formed steel sections. Two different sections, flexibility of beam-to-column joint and base conditions are the investigated variables. The result recorded showed that geometrics, joint flexibility and base conditions affect the sway stiffness of light steel frame. The increase rate is ranged from 29.2% to 47.5% for the identical tests for the effect of section depth. The ratio lies between 1.10 and 3.04 for the effect of connector thickness. In addition, beam-to-column bolted connections can contribute 34–88% of the overall frame elastic lateral stiffness for pinned bases and 17–33% for rigid base connections. Frame stability analysis with respect to global frame and column design were performed for the test specimens. Appropriate frame design analysis should be determined to provide a safe and reliable design for light steel frame considering bolted flexible joints and slender cold-formed steel sections. © 2017 Elsevier Ltd


Othman N.A.,University Tun Hussein Onn Malaysia | Piah M.A.M.,University of Technology Malaysia | Adzis Z.,University of Technology Malaysia
IET Generation, Transmission and Distribution | Year: 2017

This study reports an investigation on space charge distribution and leakage current (LC) pulses of four units of glass insulators recently removed from service. Simulation works were conducted using finite element software and validated by laboratory experiments. The simulation and experimental results were found to be in good agreement when studying the space charge distribution pattern along the glass insulator string. It is evident that the LC waveform can be used to characterise the types of partial discharge according to their occurrence with respect to the AC supply. Thus, the proposed method is viable and reliable to be applied in an online measurement system. © The Institution of Engineering and Technology 2016.


Permatasari A.R.,Trisakti University | Nazri M.J.M.,University of Technology Malaysia
AIP Conference Proceedings | Year: 2016

The emission from FBC is very dependent on a number of operating conditions (temperature, staged air, fuel feed rate, excess air, etc.) and fuel properties. This paper describes the experimental results taken in a staged air fluidized bed combustion laboratory scale, using palm fiber and palm shell as fuels and silica sand as the inert bed material. In this experiment, a variation of excess air and secondary air were measured. Measurement of gas emissions of CO and CO2 concentrations, combustion efficiency and temperature, were taken along the combustor height as well as in flue gas. The experimental results show that the axial temperature profiles decrease successively along the FBC height. The CO emission obtained was lower for the staged- air condition than for the un-staged-air condition. The combustion efficiencies show satisfactory values. © 2016 Author(s).


Tabari A.,University of Technology Malaysia | Ahmad A.,University of Technology Malaysia
Computers and Chemical Engineering | Year: 2017

Natural phenomena have been the inspiration for proposing various optimization algorithms such as genetic algorithms (GA), particle swarm optimization (PSO) and simulated annealing (SA) methods. The main contribution of this study is to propose a novel optimization method, Electro-Search algorithm, based on the movement of electrons through the orbits around the nucleus of an atom. Electro-Search (ES) algorithm incorporates some physical principals such as Bohr model and Rydberg formula, adopting a three-phase scheme. In the atom spreading phase, the atoms (i.e., candidate solutions) are randomly spread all over the molecular space (i.e., search space). In the orbital transition phase, the electrons jump to larger orbits, aiming for orbits with higher energy levels (i.e., better fitness value). The atoms are then relocated towards the global optimum point in the atom relocation phase, navigated by other atoms’ trajectory. Besides, the ES tuning parameters are progressively updated through successive iterations via a self-tuning approach developed, namely Orbital-Tuner method (OTM). The efficiency of ES algorithm is examined in various optimization problems and compared with other well-known optimization methods. The effectiveness and robustness of ES algorithm is then tested in achieving the optimal design of an industrial problem. The results demonstrated the superiority of the new ES algorithm over other optimization algorithms tested, and outperforms current optimization algorithms in real-life industrial optimization problems. © 2017 Elsevier Ltd


Valaei N.,Sunway University | Baroto M.B.,University of Technology Malaysia
Computers in Human Behavior | Year: 2017

The main purpose of this paper is to examine the continuance intention (CI) of citizens in following government Facebook page. Applying theories of expectation-confirmation, and information system success on a sample of 362 students in Malaysia, and using Partial Least Squares-Structural Equation Modelling (PLS-SEM), the study finds that CI and satisfaction of government Facebook page is contingent upon information quality (IQ) of the Facebook page per se. IQ is found as a second order construct of five first order factors: reliability, completeness, relevancy, timeliness, and understandability. Satisfaction of government Facebook page is also found as a partial mediator to the relationship between IQ and CI of following government Facebook page. In addition, applying PLS multi-group analysis, the results show that different government Facebook pages moderate the relationships between IQ and satisfaction of government Facebook page, IQ and CI of following government Facebook page as well as satisfaction of government Facebook page and CI of following government Facebook page. © 2017 Elsevier Ltd


Barkhaya N.M.M.,University of Technology Malaysia | Halim N.D.A.,University of Technology Malaysia
2016 IEEE 8th International Conference on Engineering Education: Enhancing Engineering Education Through Academia-Industry Collaboration, ICEED 2016 | Year: 2016

The evolvement of technology has made tremendous contribution in the field of education. Generally, technology of three-dimensional hologram (3DH) involve spatial displays which detaches the display technology from the user and integrate it into the real environment. This type of technology had been introduced with proven advantages for several decades especially in the field of digital art and medicine but yet to be explored in education field. This study takes a meta-Analysis approach to review the studies and provide a comprehensive analysis of ten studies from the year 2005 to 2015. These previous papers were analysed qualitatively and summarized according to the uses of 3DH as a visualization tools for teaching in various fields of education. This study shows 3DH is an effective teaching tool in attracting students' attention and enhance their understanding. This was because 3DH can dismantle a complex topic to a simpler form which improves students' comprehension. This study will provide valuable insight for educators to integrate 3DH technology as a replacement for the traditional learning method currently in use. © 2016 IEEE.


Saad N.M.,University of Technology Malaysia
2016 IEEE 8th International Conference on Engineering Education: Enhancing Engineering Education Through Academia-Industry Collaboration, ICEED 2016 | Year: 2016

Mentoring has been increasingly used in educational enhancements and development to facilitate transfer of knowledge in higher education from one lecturer to another. However, the process is unclear and lecturers are not aware of the process itself. Therefore, studies about the awareness of mentoring in universities such as in University Tenaga Nasional (UNITEN) is deemed important. This paper looks into the awareness level of lecturers in UNITEN about mentoring program. Specifically, the results of an awareness survey to all UNITEN lecturers are presented and analyzed. The survey results demonstrate various levels of knowledge of mentoring, sources of the knowledge about mentoring, respondent's attitude towards mentoring, and all common perspectives concerning mentoring. In particular, they show that mentoring program is becoming familiar to lecturers but proper documentation and peer monitoring are needed to facilitate the progress. © 2016 IEEE.


Mun S.H.,University of Technology Malaysia | Abdullah A.H.,University of Technology Malaysia
2016 IEEE 8th International Conference on Engineering Education: Enhancing Engineering Education Through Academia-Industry Collaboration, ICEED 2016 | Year: 2016

Smart boards enable students to learn and explore new concepts using technology to create a more dynamic learning experience. Students become more excited about learning when the smart boards are incorporated into the lesson. Many educators encourage the use of smart boards in teaching and learning. This paper presents a conceptual framework for the use of smart boards among students and teachers derived from an in-depth survey of the literature. The study identified the effects of the smart boards towards students' attitudes and achievement from preschool to high school as well as teachers' acceptance, difficulties, challenges, and perspectives on smart board use. The findings help articulate issues related to smart board implementation in schools and contribute to the development of smart board usage in education. © 2016 IEEE.


Salleh W.M.N.H.W.,University of Technology Malaysia | Ahmad F.,University of Technology Malaysia
Journal of Applied Pharmaceutical Science | Year: 2017

The genus Dehaasia is one of the genera of evergreen trees or shrubs belong to Lauraceae, and comprise about 35 species of tree that are distributed worldwide. The purpose of this review is to provide an update and comprehensive information on the phytochemistry and pharmacological research of Dehaasia species in order to explore their therapeutic potential and evaluate future research opportunities. All the available information on Dehaasia species was actualized systematically by searching the scientific literatures databases such as PubMed, SciFinder, Web of Science, and Google Scholar. From the data collected in this review, the genus Dehaasia has attracted much attention due to their richness in alkaloids with various bioactivities, and it comprises a wide range of therapeutically promising plants. Therefore, a detailed study and clinical evaluation of Dehaasia species should be carried out in future for the safety approval of therapeutic applications. © 2017 Wan Mohd Nuzul Hakimi Wan Salle and Farediah Ahmad.


Algamal Z.Y.,University of Technology Malaysia | Lee M.H.,University of Technology Malaysia
SAR and QSAR in Environmental Research | Year: 2017

A high-dimensional quantitative structure–activity relationship (QSAR) classification model typically contains a large number of irrelevant and redundant descriptors. In this paper, a new design of descriptor selection for the QSAR classification model estimation method is proposed by adding a new weight inside L1-norm. The experimental results of classifying the anti-hepatitis C virus activity of thiourea derivatives demonstrate that the proposed descriptor selection method in the QSAR classification model performs effectively and competitively compared with other existing penalized methods in terms of classification performance on both the training and the testing datasets. Moreover, it is noteworthy that the results obtained in terms of stability test and applicability domain provide a robust QSAR classification model. It is evident from the results that the developed QSAR classification model could conceivably be employed for further high-dimensional QSAR classification studies. © 2017 Informa UK Limited, trading as Taylor & Francis Group.


Azman N.F.,University of Technology Malaysia | Samion S.,University of Technology Malaysia
Strojniski Vestnik/Journal of Mechanical Engineering | Year: 2017

Vegetable oils have gained global att-ention to be used as an alternative lubricant to reduce the dependency on natural resources of petroleum-based lubricants due to concern over environmental problems. In this study, a refined, bleached and deodorized (RBD) palm stearin was chosen as the base lubricant, and its lubrication performance was investigated using a pin-on-disk tribotester. A zinc dialkyl-dithiophosphate (ZDDP) additive in concentrations of 1 wt%, 3 wt% and 5 wt% was blended with RBD palm stearin to improve the lubrication performance of the base lubricant. Commercial semi-synthetic oil (SAE15W50) was used for comparison purposes. The experiments were conducted under various sliding speeds (1.5 ms-1, 2.5 ms-1 and 3.5 ms-1) under normal force of 9.81 N for an hour. The lubrication performance of the tested lubricants was presented by the coefficient of friction, wear scar diameter, wear rate, surface roughness and wear worn surface of the pin specimen. The results show that an increase in ZDDP concentrations has improved the lubrication performance of the RBD palm stearin. RBD palm stearin with 5 wt% ZDDP additive shows a smaller coefficient of friction than that of SAE15W50, but creates a slightly larger wear scar diameter and wear rate. © 2017 Journal of Mechanical Engineering. All rights reserved.


Mohammadhosseini H.,University of Technology Malaysia | Yatim J.M.,University of Technology Malaysia
Journal of Cleaner Production | Year: 2017

With the increasing amount of waste generation from different processes, there has been a growing interest in the use of waste in producing sustainable building materials to achieve potential benefits. This study investigated the influence of waste polypropylene carpet fibers and palm oil fuel ash (POFA) on the microstructure and residual properties of concrete composites exposed to elevated temperatures. Four mixes containing carpet fibers (0% and 0.5%) and POFA (0% and 20%) were prepared. The specimens were exposed to high temperatures (200, 400, 600 and 800 °C) for 1 h. The fire resistance of the concrete specimens was then measured in terms of mass loss as well as both residual ultrasonic pulse velocity (UPV) and compressive strength. The role of carpet fibers and POFA was investigated through the analysis of the microstructure in terms of scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results revealed that the addition of waste polypropylene carpet fibers to the concrete matrix significantly enhanced the fire resistance and residual compressive strength in addition to eliminating the explosive spalling behavior of the concrete composites at elevated temperatures. The fire resistance of the concrete mixtures was further enhanced by the inclusion of POFA. The study revealed that the utilization of waste carpet fiber and palm oil fuel ash in the production of sustainable green concrete is feasible both technically and environmentally. © 2017 Elsevier Ltd


Shadhan R.M.,University of Technology Malaysia | Bohari S.P.M.,University of Technology Malaysia
Asian Pacific Journal of Tropical Biomedicine | Year: 2017

Objective: To provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme, glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from Hibiscus sabdariffa Linn. fruit. Methods: The inhibitory action of methanolic extract and fractions of such fruit on α-glucosidase enzyme and glucose movement through in vitro assay assessment was reported. Their activities on wound healing were tested using the scratch assay. Results: Ethyl acetate fraction at 50 mg/mL concentration exhibited significant α-glucosidase inhibition (95.79 mg/mL) with P < 0.05. At the same concentration, the methanolic extract as well as other fractions revealed lower α-glucosidase inhibition and higher glucose diffusion retardation across the dialysis tube than the control. Ethyl acetate and butanol fractions displayed notably higher glucose diffusion inhibitory activity of 5.21 mmol/L and 5.2 mmol/L, respectively as compared to methanolic extract and n-hexane fraction of 6.58 mmol/L and 6.49 mmol/L, respectively. Conversely, compared to other fractions the methanolic extract and ethyl acetate fraction manifested proliferative effect at the incubation time of 6 h during the wound healing study. Conclusions: It is established that methanolic extract and fractions from H. sabdariffa Linn. fruit can inhibit the α-glucosidase enzyme and glucose movement as well as influence the wound healing activity positively. © 2017 Hainan Medical University.


Chang M.M.F.,University of Technology Malaysia | Ginjom I.R.,University of Technology Malaysia | Ng S.M.,University of Technology Malaysia
Sensors and Actuators, B: Chemical | Year: 2017

The utilisation of pesticides has become more intensified as to fulfil the demand of food for the ever-growing world population. It leads to the risk of pesticides residues leaching to the environment, which subsequently reflects to the needs of having effective and economical detection and monitoring approach. In view of this, a work has been performed as reported in this paper on the development of a simple and economical single-shot optical probe for the detection of paraoxon-ethyl pesticide on real vegetable samples. The probe adopted carbon dots as sensing receptor that has been synthesised in-house via simple acid carbonisation of sucrose. The carbon dots isolated showed strong yellow fluorescence with the maximum emission at 524 nm when excited at 423 nm. Upon edition with paraoxon-ethyl, the emission was quenched accordingly with concentration dependent manner. The sensing protocol was optimised and validated, while the analytical characteristic was evaluated as an effective single-shot probe that can detect paraoxon-ethyl extracted from spiked vegetable leaves. The probe has achieved a limit of detection (LOD) of 0.22 ± 0.02 μM and a dynamic linear range up to 5.80 mM. © 2016 Elsevier B.V.


Usman J.,University of Technology Malaysia | Sam A.R.M.,University of Technology Malaysia | Hussin M.W.,University of Technology Malaysia
Journal of Materials in Civil Engineering | Year: 2017

This study examines the effect of a ternary blend of palm oil fuel ash (POFA) and metakaolin (MK) on the behavior of cement mortar exposed to elevated temperatures. The ternary blend was produced by combining 10% POFA and 10% MK by weight as a substitute to cement. Three additional samples which include plain portland cement (OPC), 20% MK binary and 20% POFA binary were also produced for comparison. Compressive strengths and ultrasonic pulse velocities of the mortar samples after heating to temperatures of 200, 400, 600, and 800°C for 2 h were assessed. Furthermore, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy analysis were carried out to examine the microstructure of the samples. The results show that the compressive strength and microstructure of mortar exposed to elevated temperatures improved with the simultaneous use of POFA and MK compared to plain OPC mortar and when POFA or MK is singly used. The ternary blend of cement/POFA/MK can, therefore, be used as a fire resistant material. © 2016 American Society of Civil Engineers.


Ab Talib M.H.,University of Technology Malaysia | Mat Darus I.Z.,University of Technology Malaysia
JVC/Journal of Vibration and Control | Year: 2017

This paper presents a new approach for intelligent fuzzy logic (IFL) controller tuning via firefly algorithm (FA) and particle swarm optimization (PSO) for a semi-active (SA) suspension system using a magneto-rheological (MR) damper. The SA suspension system's mathematical model is established based on quarter vehicles. The MR damper is used to change a conventional damper system to an intelligent damper. It contains a magnetic polarizable particle suspended in a liquid form. The Bouc-Wen model of a MR damper is used to determine the required damping force based on force-displacement and force-velocity characteristics. The performance of the IFL controller optimized by FA and PSO is investigated for control of a MR damper system. The gain scaling of the IFL controller is optimized using FA and PSO techniques in order to achieve the lowest mean square error (MSE) of the system response. The performance of the proposed controllers is then compared with an uncontrolled system in terms of body displacement, body acceleration, suspension deflection, and tire deflection. Two bump disturbance signals and sinusoidal signals are implemented into the system. The simulation results demonstrate that the PSO-tuned IFL exhibits an improvement in ride comfort and has the smallest MSE for acceleration analysis. In addition, the FA-tuned IFL has been proven better than IFL-PSO and uncontrolled systems for both road profile conditions in terms of displacement analysis. © The Author(s) 2015.


Zare M.R.,University of Technology Malaysia | Muller H.,University of Applied Sciences and Arts Western Switzerland
Pacific Asia Conference on Information Systems, PACIS 2016 - Proceedings | Year: 2016

Medical image retrieval systems have gained high interest in the scientific community due to the advances in medical imaging technologies. The semantic gap is one of the biggest challenges in retrieval from large medical databases. This paper presents a retrieval system that aims at addressing this challenge by learning the main concept of every image in the medical database. The proposed system contains two modules: a classification/annotation and a retrieval module. The first module aims at classifying and subsequently annotating all medical images automatically. SIFT (Scale Invariant Feature Transform) and LBP (Local Binary Patterns) are two descriptors used in this process. Imagebased and patch-based features are used as approaches to build a bag of words (BoW) using these descriptors. The impact on the classification performance is also evaluated. The results show that the classification accuracy obtained incorporating image-based integration techniques is higher than the accuracy obtained by other techniques. The retrieval module enables the search based on text, visual and multimodal queries. The text-based query supports retrieval of medical images based on categories, as it is carried out via the category that the images were annotated with, within the classification module. The multimodal query applies a late fusion technique on the retrieval results obtained from text-based and image-based queries. This fusion is used to enhance the retrieval performance by incorporating the advantages of both text-based and content-based image retrieval.


Meng Guan T.,University of Technology Malaysia | Rahim S.K.A.,University of Technology Malaysia
Microwave and Optical Technology Letters | Year: 2017

In this project, a compact monopoles Multiple-Input-Multiple-Output MIMO antenna with size 40 × 42 mm2 that operates at 7 GHz is designed and proposed for 5th Generation mobile networks (5G) application. The antenna is built by using FR-4 substrate and it consists of two planar antenna elements which arranged orthogonally to provide a good isolation between them. To further enhance the isolation and decrease the mutual coupling effect, a rod-like parasite element is added in the design. Initial simulation result shows that the antenna can operate from 4 GHz to 9 GHz while measurement result proves that it can operate from 5.5 GHz to 9 GHz. Both results show that isolation is below −20 dB. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1074–1077, 2017. © 2017 Wiley Periodicals, Inc.


Mohammadhosseini H.,University of Technology Malaysia | Abdul Awal A.S.M.,University Tun Hussein Onn Malaysia | Mohd Yatim J.B.,University of Technology Malaysia
Construction and Building Materials | Year: 2017

The utilization of waste materials is one of the fundamental issues of waste management strategies in many parts of the world. With the advances in cement and concrete technology, the use of waste materials in the concrete industry has developed gradually widespread because of technological, economic and ecological advantages. This paper presents the potential use of waste polypropylene carpet fibres, and highlights the impact resistance and mechanical properties of concrete with the fibres. Six volume fractions varying from 0 to 1.25% of 20-mm-long carpet fibres were used with ordinary Portland cement (OPC) concrete mixes. Another six mixes were made where OPC was replaced by 20% palm oil fuel ash (POFA) as supplementary cementing material. It has been found that the addition of polypropylene carpet fibre decreased the slump values and increased the VeBe time of fresh concrete. The inclusion of carpet fibre to either OPC or POFA concrete mixes did not improve the compressive strength at early ages. At later ages, however, the compressive strength of the mixtures containing POFA significantly increased and the obtained values were higher than that mixes with OPC alone. The positive interaction between carpet fibres and POFA leads to high tensile strength, flexural strengths and impact resistance, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. It is concluded that waste carpet fibres and palm oil fuel ash can be used as building materials in the construction of sustainable concrete. © 2017 Elsevier Ltd


Lee Y.H.,University of Technology Malaysia | Shek P.N.,University of Technology Malaysia | Mohammad S.,University of Technology Malaysia
Construction and Building Materials | Year: 2017

Interlocking blocks have been actively applied into current wall systems in the construction industry and limited references can be found on the axial loaded compressed column. Therefore, in this research, interlocking blocks have been innovatively assembled as columns for developing a new system that can replace the conventional concrete construction to block construction, without concrete beams and columns. These interlocking block columns are tested in the laboratory in order to investigate their structural performance under axial load. The fresh and harden properties of infills have been recorded. As the compressive strength of infill materials increased, the initial stiffness and strength showed a significant growth. An incrementing trend was also noted when increasing the reinforcement bar size. Pearson and partial correlation analysis showed infills have significant correlation with column compressive capacity. Comparison has been conducted between experimental results, Eurocode reinforced concrete and Masonry Standards Joint Committee (MSJC) design specifications. The differences were ranged from 0.65 to 1.85. Parametric study with variables of infills and reinforcement bar was carried out by adopting the Eurocode design to interlocking block columns and introducing a 0.8 reduction factor. Design recommendations have been made where the strength of infills should limit to 50 MPa and reinforcement bar size should not greater than 30 mm. As the dimension in assembling the column, further reduction on slenderness can be ignored. © 2017 Elsevier Ltd


Zheng C.Y.,University Tunku Abdul Rahman | Yunus J.,University of Technology Malaysia
IECBES 2016 - IEEE-EMBS Conference on Biomedical Engineering and Sciences | Year: 2016

This paper presents studies on the Accessibility, Affordability, and Availability (3As) of Long-Term Monitoring System for Children with Movement Disorders whereby a tele monitoring system is proposed to perform such analysis in the Malaysian context. The system consists of a few subsystems that will acquire, detect, analyze, transmit, and storage of various gait parameters that are useful in gait analysis of children with movement disorders. The system is based on Microsoft Kinect depth sensors as primary sensing elements, incorporated with dedicated data-logging facilities. It also leveraged on the power of technologies via Internet of Things (IoT), with utilization of cloud storage, and processing as well as mobile applications. And this system is anticipated to provide 3As to the local communities-in-need. © 2016 IEEE.


Zainal M.A.,University of Technology Malaysia | Mohamed Ali M.S.,University of Technology Malaysia
IECBES 2016 - IEEE-EMBS Conference on Biomedical Engineering and Sciences | Year: 2016

A wireless shape-memory-polymer-based implantable drug-delivery device operated by external radio frequency magnetic fields is designed and fabricated. The shape-memory-polymer actuator is driven by a wireless resonant heater which is bonded directly to it activated only when the field frequency is tuned to the resonant frequency of the heater. The device is operated using radiofrequency power of 0.05 W. Experiments are conducted to demonstrate the application of the developed implantable drug-delivery device using food coloring and acidic solution loaded in the device reservoir. The device is successfully operated in DI water through wireless activation and acidic solution stored in the reservoir is released and diffused in water with average release rate of 0.172 μL/min. © 2016 IEEE.


Daud S.S.,University of Technology Malaysia | Sudirman R.,University of Technology Malaysia
IECBES 2016 - IEEE-EMBS Conference on Biomedical Engineering and Sciences | Year: 2016

Nowadays, there are a quite study on human memory either in investigating it function, factors affect it performance and it relation with the cognitive ability. But only a few of the studies was discussed based on brain activity. Most of the study only focused on the correct response or score result of the task. Thus, this present study aims to improve the limitations. The brain response is investigates during memorization based on electroencephalography (EEG) analysis. EEG is an imaging technique that able to record the brain electrical signal in a short time. The visual working memory task with two difficulty level (easy and difficult) was preferred for experiment. Sixty healthy subjects were required to memorize the visual task at three different conditions; silent and listening to Mozart music k448 and pure white noise in 2 minutes. The sound intensity was controlled at 40 to 55 dB to minimize the effect of volume on subject. There were two measurements which were memorizing test score and brain activity was used to evaluate the memory performance of the subject. During memorizing process, the brain activity was recorded using 10-20 electrode placement system of Neurofax 9200 EEG acquisition machine. The Fp1, Fz, F8, T3, T4, T5, T6, Pz, O1 and O2 channels were selected for analyzing process by using MATLAB software. The wavelet approach was used to process the raw EEG data. Based on the result, it showed that the memory performance was influenced when the environmental condition was changing. Different pattern of EEG signal has been found for different conditions based on the relative power of frequency band. © 2016 IEEE.


Sabbagh F.,University of Technology Malaysia | Muhamad I.I.,University of Technology Malaysia
Journal of the Taiwan Institute of Chemical Engineers | Year: 2016

Polyacrylamide-based hydrogels were obtained by chemical crosslinking of MBA using acrylamide, sodium carboxymethylecellulose (NaCMC), N, N, N', N'-tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as the initiators. The interest on MgO nanoparticle is not only due to their stability under harsh process conditions but also for human health, where they are known to be necessary minerals. The systems were characterized with regard to the rheology behavior of hydrogel, degree of crosslinking the polymers, Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscope (FESEM). The dispersion of the nanoparticles (MgO) and drug (Acyclovir) inside the hydrogel was shown by TEM. Acyclovir, that is one of the famous drugs to treat the vaginal infections, was loaded in the polymer through the soaking method in an aqueous solution including the drug for drug delivery and release in the vaginal. The physical and chemical characterizations of the fortified hydrogels provided an assessed report on the morphological structure of the polymer, swelling behavior, bonding formation of gels and physical properties. To study the drug release in two different mediums, PBS and SVF aqueous solutions were utilized. To determine the amount of released drug from the hydrogels, HPLC was used. The pH sensitivity and the in vitro drug release of hydrogels in three different pH (pH 4,6,8) was studied. The objectives of this present study are to characterize the MgO nanocomposite hydrogel and to study the effect of different buffers on the release of Acyclovir from hydrogels. © 2016 Taiwan Institute of Chemical Engineers.


Elghariani K.,University of Technology Malaysia | Kama N.,University of Technology Malaysia
2016 3rd International Conference on Computer and Information Sciences, ICCOINS 2016 - Proceedings | Year: 2016

The popularity of agile methodology has been increased since agile offers further collaboration. Requirements engineering (RE) is one of the software development process in agile approaches. The features of face to face communication is one of agile way which unlike to other traditional software methods. Software developers are using the definition agile way to improve the agile way of activities. Besides, the challenge of dealing with RE practices is not much is known in agile way or model. However, many literature works have been done in RE in agile approaches and challenges faced by teamwork. The aim of this paper is to fill the gap by presenting RE practices in agile methodology also the challenges of RE activities which are faced by agile team members. 80 systematic literature reviews are conducted and 22 research papers are identified. Moreover, the reviews discuss RE in agile methodology approaches. This paper has adopted a systematic literature review and has applied a certain inclusion and exclusion criteria to detect the research studies related to RE in agile methodology to achieve the aim of this research. This research determined most of agile requirements engineering activities, also challenges of requirements engineering in agile methodology. Therefore, the research findings can be a reference to all researchers who are interested in this research area because the paper's findings clarify that RE in agile methodology need to have further attention by researchers and more practical results are needed to gain understandable information about RE practices in Agile methodology. © 2016 IEEE.


Bakar N.A.A.,University of Technology Malaysia | Selamat H.,University of Technology Malaysia
2016 3rd International Conference on Computer and Information Sciences, ICCOINS 2016 - Proceedings | Year: 2016

Enterprise Architecture (EA) is gaining its importance and has become significant agenda in any Information Technology (IT) transformation in most organisation. Despite of many EA frameworks and methodologies available, the implementation of EA is a challenging process. Therefore, this paper aims to explore the process of EA implementation in an organisation and to identify its critical success factors (CSFs). An integrated framework comprising of Configurable Process Model (CPM) and Balanced Scorecard (BSC) are used in this study. The findings are categorised into six perspectives which are authority support, internal process, learning and growth, cost, technology and talent management. Based on Ministry of Health Malaysia (MOHM) as a case study, it reveals that every organisation should define and design their own EA solution based on their core business and need. The existence of framework and documentation does not represent the successful EA if it is not being practiced in the organisation. The EA implementation experience and the CSFs discussed in this paper will be valuable guidelines for other EA implementer in other public sector organisation. © 2016 IEEE.


Rabat N.E.,Petronas University of Technology | Hashim S.,University of Technology Malaysia | Majid R.A.,University of Technology Malaysia
Procedia Engineering | Year: 2016

The combination of hydrogel and fertilizer as slow release fertilizer hydrogel (SRFH) has become one of the promising materials to overcome the shortcomings of conventional fertilizer by decreasing fertilizer loss rate, supplying nutrients sustainably, and lowering frequency of irrigation. A comparative study on water retention and plant growth performances of SRFH made from three hydrophilic monomers; acrylic acid (AA), acrylamide (AAm) and AA-co-AAm was executed. PAA SRFH has smaller swelling rate constant, k as it required only 166.67 minutes to absorb 0.63 of its equilibrium capacity of swelling, followed by P(AA-co-AAm) SRFH and PAAm SRFH. Although PAAm SRFH has the lowest swelling rate constant, it has the most excellent water retention ability in soil followed by P(AA-co-AAm) SRFH. Additionally, the presence of PAA SRFH in soil has enhanced the plant growth performances of model plant (capsicum annum) in term of its average leaf width and plant height. The synergistic effects of acrylic acid and acrylamide in P(AA-co-AAm) SRFH could be utilized to produce hydrogel used in agriculture. © 2016 The Authors.


Said M.S.M.,University of Technology Malaysia | Seman N.,University of Technology Malaysia
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2017

Gelatin-based material can be used in phantom modeling for microwave imaging applications, but unfortunately, this type of phantom has a short life span. Formaldehyde has been used previously to preserve gelatin-based material, but it might be hazardous. This paper presents a life-span study for gelatin-based material that has been preserved by vinegar in different amounts, observed through the conducted dielectric measurement from 1 GHz to 6 GHz. The Debye parameters are derived to define a Debye relaxation model of the acid contents in a solution of water and vinegar. The study is then focused on dielectric trends prior to and after the addition of different amounts of vinegar into a gelatin-based material. The life-span study concentrates on changes in the sample's dielectric properties over a storage period of six weeks. The obtained findings in this study are useful to validate the suitability of vinegar to be used as preservative in gelatin-based material for microwave imaging purposes. © 1994-2012 IEEE.


Yee F.C.,University of Technology Malaysia | Abd Razak S.I.,University of Technology Malaysia
Materials Science Forum | Year: 2017

Bacterial cellulose (BC) is the cellulose which is produced by specific bacteria such as Acetobacter xylinum, Agrobacterium, Gluconacetobacter, Rhizobium, Achromobacter, Alcaligenes, Aerobacter, Azotobacter, Salmonella, Esherichia, and Sarcina. Surface modification of bacterial cellulose (BC) by coating with synthetic biodegradable polyester on it was reported. BC films were coated with the polymer at different concentrations in order to improve the surface structure of BC. Tear and burst indices of the BC film were increased with such modification. © 2017 Trans Tech Publications, Switzerland.


Hooi L.W.,University of Nottingham Malaysia Campus | Leong T.Y.,University of Technology Malaysia
Journal of Quality in Maintenance Engineering | Year: 2017

Purpose - The purpose of this paper is to examine the multidimensionality of total productive maintenance (TPM) and its relationship with manufacturing performance improvement in the Malaysian manufacturing sector. Specifically, this study evaluates the contribution of each TPM success factors in improving manufacturing performance. Design/methodology/approach - Data from 89 employees who participated in the survey were used to test the proposed research framework. A structured questionnaire adopted from Ahuja and Khamba (2006) was used to assess the Malaysian context. Findings - The analytical results reveal that traditional maintenance initiatives and TPM implementation initiatives significantly affect manufacturing performance, but not top management leadership and maintenance organisation. Top management roles and commitment are critical in the early stage to determine the master plan and initiate the implementation of the whole programme. However, traditional maintenance and TPM implementation initiatives gradually enable engagement, proper planning, right execution and continuous improvement, ultimately improving the manufacturing performance indicators significantly. The findings further unveil that TPM is not sustainable in Malaysia's manufacturing organisations in the long run. Practical implications - This analysis is vital for senior managers of manufacturing organisations that have implemented TPM or are considering introducing TPM in their organisations. Originality/value - This study contributes to the literature by examining beyond the introduction and stabilisation phase of TPM to provide an insight of whether TPM is sustainable in the long run. © Emerald Publishing Limited.


Tan L.P.,University of Technology Malaysia | Wong K.Y.,University of Technology Malaysia
Cybernetics and Systems | Year: 2017

This paper aims to devise a model for predicting the knowledge management (KM) effect on manufacturing performance via neural network (NN). This is the first empirical study that applies NN to forecast manufacturing performance using 48 KM metrics which cover knowledge resources, KM processes, and KM factors. The training, validation, and testing of the NN model were based on 580 usable data points of KM and manufacturing performance collected from manufacturing companies in Malaysia. The research findings reveal that the NN model serves as a reliable yet simple tool to predict the manufacturing performance of a company by considering various essential KM metrics. The network prediction is in good correlation with the actual data. Lastly, the prediction model will be useful for practitioners to determine future KM strategies and targets to improve manufacturing performance. © 2017 Taylor & Francis Group, LLC


Lee C.S.,University of Technology Malaysia | Wong K.Y.,University of Technology Malaysia
Cybernetics and Systems | Year: 2017

To improve a knowledge management (KM) initiative, its effectiveness and performance has to be evaluated so that the area which is deficient can be improved. Yet, there is a lack of knowledge management performance measurement (KMPM) systems and this is apparent in the case of small and medium enterprises (SMEs), as most of the studies have focused on large organizations. Furthermore, KM is characterized by an environment subject to uncertainties and fuzziness, thus there is a need to adopt a specific approach to address this issue. Hence, this article intends to present the development of a KMPM system using a fuzzy logic methodology specifically for the SME sector. MATLAB and Simulink were used to develop the KMPM system and case studies were conducted in three small and medium-sized consultancy companies to evaluate it. The case studies showed that the developed KMPM system is suitable for SMEs and further improvement was made to the system. © 2017 Taylor & Francis


Babayo A.A.,University of Technology Malaysia | Anisi M.H.,University of Technology Malaysia | Ali I.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2017

Wireless Sensor Networks (WSNs) are becoming more and more integrated into industrial and domestic systems such as transport, home automation, etc. However, due to their own characteristics, there are several issues which affect their performance. Some of the issues are briefly presented, but the emphasis is on energy constraint. Energy harvesting as one of the sources of energy in WSNs is found to be the most reliable, and this review is about energy management schemes for this source. The energy management schemes are designed for efficient use of harvested energy. The review puts the energy management schemes into classes that represent different application requirements. © 2017 Elsevier Ltd


Das H.S.,University of Technology Malaysia | Tan C.W.,University of Technology Malaysia | Yatim A.H.M.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2017

Fuel cell (FC) application in vehicular technology has gained much popularity since the past few years. Typically, fuel Cell Hybrid Electric Vehicle (FCHEV) consists of fuel cell, battery and/or ultracapacitor (UC) as the power sources. The power converter is integrated to the power sources to form the hybrid FC system. This helps to compensate the drawback of individual power sources. Apart from the technical efficiency of power sources itself, the performance of an FCHEV is governed by the efficiency of power electronics and associated controller. In this paper, a state-of-the-art of vehicle classification is reviewed, in which the focus is placed on the deployment of fuel cell, battery, ultracapacitor and flywheel. The configurations used in FCHEV, followed by the updated power converter topologies, are also discussed. The topologies are categorized and discussed according to the power stages and control techniques used in the configurations. Then, multiple stages conversion and single stage topologies are described chronologically. The advantages and disadvantages of each topology, safety standards, current situation and environmental impact of FCHEV are also discussed. In addition, the current development of FCHEV, challenges and future prospects are also elaborated. The rapid growth of FC based research and technology has paved great prospects for FCHEVs in the near future, with the prediction of the competitive cost of hydrogen as compared to gasoline. © 2017 Elsevier Ltd


Ali M.,University of Technology Malaysia | Yusof K.M.,University of Technology Malaysia
International Conference on Control, Automation and Systems | Year: 2016

Failures at degumming and bleaching process in palm oil refining affect plant performance, production delay, and loss to the company. In current practice, troubleshooting in these process relies on human knowledge and trial and error method which can caused other failures and time consuming. In this study, fuzzy logic model was developed for troubleshooting degumming and bleaching process using Mamdani approached. Operating conditions at bleacher vessel, ejector, condenser, hotwell and cooling tower system were selected as input and output variables in the fuzzy logic model development. Qualitative and numerical data were collected in this study by interviewing plant workers, observing distributed control system (DCS), reviewing standard operating procedure (SOP), operation checklist and plant manuals. The relationship between input and output variables were described by fuzzy membership function and fuzzy rules. Centre of gravity method (COG) method was used for defuzzification. The proposed model was tested with real plant data and the model was shown successfully perform troubleshooting task and suggest necessary action. Therefore, this model has the potential to employed by operator and inexperience workers in palm oil industry. © 2016 Institute of Control, Robotics and Systems - ICROS.


Belhocine A.,University of Science and Technology of Oran | Omar W.Z.W.,University of Technology Malaysia
International Journal on Interactive Design and Manufacturing | Year: 2017

The complexity of the physical or technological systems to be developed or studied led to employing numerical methods based on the principle of an approach as possible nominal solution, but these require large computations requiring efficient computers. The computer code ANSYS also allows the determination and the visualization of the structural deformations due to the contact of slipping between the disc and the pads. The results of the calculations of contact described in this work relate to displacements, Von Mises stress on the disc, contact pressures of the inner and outer pad at various moments of simulation. One precedes then the influence of some parameters on the computation results such as rotation of the disc, the smoothness of the mesh, the material of the brake pads and the friction coefficient enter the disc and the pads, the number of revolutions and the material of the disc, the pads groove. © 2017 Springer-Verlag France


Bassel A.,University of Anbar | Nordin M.J.,University of Technology Malaysia
2017 IEEE 7th Annual Computing and Communication Workshop and Conference, CCWC 2017 | Year: 2017

The Glowworm Swarm Optimization (GSO) is a population-based metaheuristic algorithm for optimization problems. Limitations of GSO are shown at the convergence speed and a weakness in the capability of global search which need to be improved. Thus, Memory Mechanism and Mutation for Glowworm Swarm Optimization (MMGSO) are proposed in this study to improve the GSO performance at the reported aspects. The proposed method is examined on Unimodal and Multimodal benchmark functions to prove the productivity of the MMGSO algorithm regarding to three metrics which are solution quality, convergence speed and robustness. The results of MMGSO are analyzed and compared with the basic GSO to show the efficiency of the proposed method. © 2017 IEEE.


Bakar N.A.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia
2nd International Symposium on Agent, Multi-Agent Systems and Robotics, ISAMSR 2016 | Year: 2016

Crowdsourcing is an agent-based system running in distributed open environment where agents interact and share information with each other in a community. While performing activities in open system, agent personal information may be disclosed due to several factors such as agent preferences, decisions and behavior. These factors are continuously changing during runtime depending on the activities executed within the system. As a result, there are risks of agent safety such as the disclosures of agent identity and location. Hence, in this research, a solution is proposed to detect agent data confidentiality violations that occur during runtime. The proposed solution includes the definition of data confidentiality as agent quality properties and the violations detection using Runtime Verification and Quality Assessment process. The effectiveness of the proposed solution is evaluated by implementing the detection process within Crowdsourced Navigation System model. © 2016 IEEE.


Mohamad M.M.,University of Technology Malaysia | Kheirabadi M.T.,Islamic Azad University at Gorgan
Proceeding - 2016 2nd International Conference on Science in Information Technology, ICSITech 2016: Information Science for Green Society and Environment | Year: 2016

Unique characteristic of underwater environments is challenging for wireless sensor network protocol. Opportunistic routing protocol is the most promising routing method to encounter the challenges. This paper will review three main algorithms; forwarding set selection and forwarding set ranking algorithms to handle FSR problem, void handling algorithm to handle the communication void (CV) problem, and overhear and suppression algorithm to deal with duplicate forwarding suppression (DFS) problem. The importance of the review is that it will direct the study to energy efficient pressure-based opportunistic routing algorithm for underwater wireless sensor network (UWSN). © 2016 IEEE.


Jayamani E.,University of Technology Malaysia | Bin Bakri M.K.,University of Technology Malaysia
Materials Science Forum | Year: 2017

In this research, the alkaline treated and untreated sugarcane bagasse was used as reinforcement with unsaturated polyester to make composites. The composites were made with 0 to 20 weight percentage of fibers using compression molding. Acoustical, dielectrical and mechanical properties of the composites were studied according to the American Society for Testing Materials (ASTM) standards. The result shows that the composites with higher sugarcane bagasse loading show higher acoustical and dielectrical properties. The composites tensile strength increased up to 10wt% of fiber loading and then starts decreasing eventually. Tensile strength and sound absorption coefficients of alkali treated fiber composites shown slightly better results than untreated fiber composites. The dielectric constant of treated fiber composites were lower compared with untreated fiber composites. © 2017 Trans Tech Publications, Switzerland.


Hii K.U.,University of Technology Malaysia
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

A novel method for optical beam collimation measurement is presented. The collimating lens is utilized in four parts of quadrants with the beam aligned onto the first quadrant and configured to pass the subsequent quadrants. This allows the test beam to pass the collimating lens for four times. Subsequently, the test beam is reversed to achieve a total number of eight passes. Hence, for a defocus introduced, the collimation state of the test beam can be evaluated at the amplification of eight. The evaluation of the test beam is performed based on the approach of collimation testing using lateral shearing interferometer. The proposed technique provides a differential collimation sensitivity for accurate setting of a highly collimated beam. © 2016 SPIE.


Ismail S.,University of Kuala Lumpur | Ismail S.,University of Technology Malaysia
Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 | Year: 2017

The administrative task of advising students has been part of the academicians' scope of work in some institutes of higher learning. Other than making sure that the students are registering the right courses every semester, the academicians' key performance index might include ensuring that the students graduate on time. This happens in a private university in Malaysia, in which this research is based on. Since the inception of agent-mediated personal knowledge management (PKM) concept in 2011, most research covered the area of education management, such as class management, social media in education, and academic quality management. Seeing the opportunity in applying the PKM concept to one of the most critical process in academic management, this paper presents an idea of agent-mediated academic advising system. The result presented in this paper includes the processes of academic advising, and how the knowledge agent could be deployed to advise both the advisor and students. © 2017 ACM.


Ng S.C.,University of Technology Malaysia | Ali F.D.M.A.,University Lurio Mozambique
2016 3rd International Conference on Information Retrieval and Knowledge Management, CAMP 2016 - Conference Proceedings | Year: 2016

Selecting a classification model to deploy in educational systems is a very sensitive process since it is necessary to guarantee that the model will work well after being deployed in a real situation and at the same time the model needs to be friendly to the users involved in the educational settings. The goal of this paper is to select an accurate and easy-to-understand model to serve as a basis to build a new reporting module in Moodle system for predicting students' success. With this objective, two experiments were conducted in order to assess the quality of different classifiers with respect to performance and comprehensibility. In the first experiment, the performances of different models were evaluated based on the Accuracy criteria. In the second experiment, different respondents provided their subjective opinion about the models' comprehensibility. The results discovered that the PART model was the most suited model to implement the report for predicting student's success. © 2016 IEEE.


Adeyemi I.R.,University of Technology Malaysia | Razak S.A.,University of Technology Malaysia | Salleh M.,University of Technology Malaysia
Proceedings - 2016 4th International Conference on User Science and Engineering, i-USEr 2016 | Year: 2016

Researches on human thinking styles have received wide attention, especially in online education; an aspect of human computer interaction. However, the deciphering of specific thinking styles of an online user has suffered setbacks due to the limited exposition on the probability of online thinking style signature of users. This study explored this limitation with the assumption that human daily behavioral pattern can be translated into the electronic media of communication frequently used. To ascertain this assumption, server-side web data of 43-respondents were collected for 10-months as well as a self-report thinking style measurement instrument for each respondent. Cluster dichotomies from two thinking styles were extracted. Various supervised machine learning techniques were then applied to distinguish individuals on each dichotomy. The result showed that thinking styles of individuals on different dichotomies can be reliably distinguished on the internet using Logistic model tree with Bagging technique. The result demonstrates a high probability of the existence of digital thinking style. The findings from this study find relevance and application in human-centered graphical user interface design for recommender system as well as in e-commerce services. It also finds application in online profiling processes especially in e-learning systems. © 2016 IEEE.


Abuelnuor A.A.A.,University of Technology Malaysia | Wahid M.A.,University of Technology Malaysia | Hosseini S.E.,University of Technology Malaysia | Saat A.,University of Technology Malaysia | And 3 more authors.
Renewable and Sustainable Energy Reviews | Year: 2014

The demands of energy and pollutant emissions reduction have motivated the combustion researchers to work on combustion improvement. Flameless combustion or high temperature air combustion has many features such as flame stability, low pollutant emission and uniform profiles of temperature compared to the other modes of combustion. Combustion of solid fuels likes biomass and wastes in flameless combustion conditions has not been investigated as comprehensive as combustion of gaseous fuels. The aim of using biomass in combustion is to reduce the pollutant emissions and to decrease the rate of fossil fuel consumption. In this review, combustion characteristics of biomass in flameless combustion are explained. The paper summarizes the research on the mass loss, ignition time, and NOx emissions during biomass flameless combustion. These summaries show that biomass under flameless combustion gives low pollutant emissions, low mass loss and it decreases the ignition time. © 2014 Elsevier Ltd.


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.


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 | Azizi S.,Razi Un. | Bahadori A.,Southern Cross University of Australia | Elkamel A.,University of Waterloo | Wan Alwi S.R.,University of Technology Malaysia
Energy | Year: 2013

Electricity is an important asset that influences not only the economy, but political or social security of a country. Reliable and accurate planning and prediction of electricity demand for a country are therefore vital. In this paper, electricity demand in Ontario province of Canada from the year 1976-2005 is modeled by using an (adaptive neuro fuzzy inference system) ANFIS. A neuro fuzzy structure can be defined as an ANN (artificial neural network) which is trained by experimental data to find the parameters of (fuzzy inference system) FIS. Inputs for the model include number of employment, (gross domestic product) GDP, population, dwelling count and two meteorological parameters related to annual weather temperature. The data were collected and screened using statistical methods. Then, based on the data, a neuro-fuzzy model for the electricity demand is built. It was found that electricity demand is most sensitive to employment. © 2012 Elsevier Ltd.


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.


Ali I.,Jamia Millia Islamia University | Sanagi M.M.,University of Technology Malaysia | Aboul-Enein H.Y.,National Research Center of Egypt
Electrophoresis | Year: 2014

NACE is an alternative technique to aqueous CE in the chiral separations of partially soluble racemates. Besides, partially water-soluble or insoluble chiral selectors may be exploited in the enantiomeric resolution in NACE. The high reproducibility due to low Joule heat generation and no change in BGE concentration may make NACE a routine analytical technique. These facts attracted scientists to use NACE for the chiral resolution. The present review describes the advances in the chiral separations by NACE and its application in pharmaceutical and biomedical analysis. The emphasis has been given to discuss the selection of the chiral selectors and organic solvents, applications of NACE, comparison between NACE and aqueous CE, and chiral recognition mechanism. Besides, efforts have also been made to predict the future perspectives of NACE. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


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

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


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.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2012

Energy plays a pivotal role in socio-economic development by raising standard of living. It is becoming gradually accepted that current energy systems, networks encompassing every thing from primary energy sources to final energy services, are becoming unsustainable. Development of conventional forms of energy for meeting the growing energy needs of society at a reasonable cost is the responsibility of the Governments. In recent years, public and political sensitivities to environmental issues and energy security have led to the promotion of renewable energy resources. Diversification of fuel sources is imperative to address these issues; and limited fossil resources and environmental problems associated with them have emphasized the need for new sustainable energy supply options that use renewable energies. Development and promotion of new non-conventional, alternate and renewable sources of energy such as solar, wind and bio-energy, etc. are now getting sustained attention. Solar power is one of the hottest areas in energy investment right now, but there is much debate about the future of solar technology and solar energy markets. This investigates the progress and challenges for solar power in Pakistan according to the overall concept of sustainable development, and identifies the region wise potential of solar power in Pakistan and its current status. Barriers are examined over the whole solar energy spectrum and policy issues and institutional roles and responsibilities are discussed. © 2012 Elsevier Ltd. All rights reserved.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2012

Water is a vital resource that supports all forms of life on earth. Progressive release of greenhouse gases (GHG) from increasing energy-intensive industries has eventually caused human civilization to suffer. During the past two decades, the risk and reality of environmental degradation have become more apparent. Renewable Energy provides an effective option for the provision of energy services from the technical point of view while hydropower, a major source of energy in the, appears an important renewable source of energy, its viability for large-scale energy production. Hydropower is renewable, reliable, clean, and largely carbon-free, and represents a flexible peak-load technology. With most of the world's hydropower potential available for near future development, it is local interests and sovereign states that decide how to manage their water resource base. In Pakistan the availability of power had been continually falling short of the demand of 24,474 MW and as a result, the country is experiencing power shortages of varying degrees in different parts of the country. Geographically, Pakistan has been blessed with river flows that are naturally supportive to electricity generation. Considering the large potential and the intrinsic characteristics of hydropower in promoting the country's energy security and flexibility in system operation, government is tried to accelerate hydropower development through number of policy initiatives. This paper investigates the progress and challenges for hydel power generation in Pakistan according to the overall concept of sustainable development and identifies the region wise potential of hydel power in Pakistan, its current status. Barriers are examined and Policy issue and institutional roles and responsibilities are discussed. © 2012 Elsevier Ltd. All rights reserved.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

Energy is one of the essential inputs for economic development and industrialization. A reliable supply of energy is essential to maintain and to improve human being's living conditions. The management of energy sources, rational utilization of energy, and renewable energy source usages are vital. Among the renewable energy sources wind energy is currently viewed as one of the most significant, fastest growing, and commercially attractive source to generate electrical energy because of the mature and cost effective energy conversation technology. Developing a utility-scale wind project is a complicated and time-consuming process which involves developers, landowners, utilities, the public and various local authorities. This article discusses the past, the present and the future of wind energy use in Pakistan. The efforts for the utilization of wind energy in the country are presented as well, along with barriers in its development. It is concluded that the potential exists, but significant efforts are needed to effectively make use of this cheap renewable energy source. © 2012 Elsevier Ltd.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Progress in Energy and Combustion Science | Year: 2013

Underground coal gasification (UCG) is a promising option for the future use of un-worked coal. UCG permits coal to be gasified in situ within the coal seam, via a matrix of wells. The coal is ignited and air is injected underground to sustain a fire, which is essentially used to "mine" the coal and produce a combustible synthetic gas which can be used for industrial heating, power generation or the manufacture of hydrogen, synthetic natural gas or diesel fuel. As compared with conventional mining and surface gasification, UCG promises lower capital/operating costs and also has other advantages, such as no human labor underground. In addition, UCG has the potential to be linked with carbon capture and sequestration. The increasing demand for energy, depletion of oil, and gas resources, and threat of global climate change have lead to growing interest in UCG throughout the world. The potential for UCG to access low grade, inaccessible coal resources and convert them commercially and competitively into syngas is enormous, with potential applications in power, fuel, and chemical production. This article reviews the literature on UCG and research contributions are reported UCG with main emphasis given to the chemical and physical characteristic of feedstock, process chemistry, gasifier designs, and operating conditions. This is done to provide a general background and allow the reader to understand the influence of operating variables on UCG. Thermodynamic studies of UCG with emphasis on gasifier operation optimization based on thermodynamics, biomass gasification reaction engineering and particularly recently developed kinetic models, advantages and the technical challenges for UCG, and finally, the future prospects for UCG technology are also reviewed. © 2012 Elsevier Ltd. All rights reserved.


Mardani A.,University of Technology Malaysia | Jusoh A.,University of Technology Malaysia | Zavadskas E.K.,Vilnius Gediminas Technical University
Expert Systems with Applications | Year: 2015

MCDM is considered as a complex decision-making tool involving both quantitative and qualitative factors. In recent years, several fuzzy FMCDM tools have been suggested to choosing the optimal probably options. The purpose of this paper is to review systematically the applications and methodologies of the fuzzy multi decision-making (FMCDM) techniques. This study reviewed a total of 403 papers published from 1994 to 2014 in more than 150 peer reviewed journals (extracted from online databases such as ScienceDirect, Springer, Emerald, Wiley, ProQuest, and Taylor & Francis). According to experts' opinions, these papers were grouped into four main fields: engineering, management and business, science, and technology. Furthermore, these papers were categorized based on authors, publication date, country of origin, methods, tools, and type of research (FMCDM utilizing research, FMCDM developing research, and FMCDM proposing research). The results of this study indicated that, in 2013, scholars have published papers more than other years. In addition, hybrid fuzzy MCDM in the integrated method and fuzzy AHP in the individual section were ranked as the first and second methods in use. Additionally, Taiwan was ranked as the first country that contributed to this survey, and engineering was ranked as the first field that has applied fuzzy DM tools and techniques. © 2015 Elsevier Ltd. All rights reserved.


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.


Talebian-Kiakalaieh A.,University of Technology Malaysia | Amin N.A.S.,University of Technology Malaysia | Mazaheri H.,University of Technology Malaysia | Mazaheri H.,Islamic Azad University of Arak
Applied Energy | Year: 2013

Fossil fuel depletion, environmental concerns, and steep hikes in the price of fossil fuels are driving scientists to search for alternative fuels. The characteristics of biodiesel have made the pursuit of high quality biodiesel production attractive. Utilization of waste cooking oil is a key component in reducing biodiesel production costs up to 60-90%. Researchers have used various types of homogeneous and heterogeneous catalyzed transesterification reaction for biodiesel production. Meanwhile, the effect of novel processes such as membrane reactor, reactive distillation column, reactive absorption, ultrasonic and microwave irradiation significantly influenced the final conversion, yield and in particular, the quality of product. This article attempts to cover all possible techniques in production of biodiesel from waste cooking oil. © 2012 Elsevier Ltd.


Hadibarata T.,University of Technology Malaysia | Yusoff A.R.M.,University of Technology Malaysia | Kristanti R.A.,Yamanashi University
Water, Air, and Soil Pollution | Year: 2012

Utilization of microbes including white-rot fungi and bacterial strains for decolorization of synthetic dyes is one promising strategy of an environmentally friendly and cost-competitive alternative to physicochemical decomposition processes for treating industrial effluents. In this study, the biodegradation ability of the white-rot fungi Polyporus sp. S133 that produce high laccase was investigated in order to decolorize anthraquinone-type dye. Parameter including pH, temperature, and non-ionic surfactant were used to comparatively study the decolorizing effects on Remazol Brilliant Blue R (RBBR). The purified laccase totally decolorized 200 mg L -1 initial concentration of RBBR dye when only 1.5 UL -1 of laccase was used in the reaction mixture. The optimal decolorization rates were achieved at pH 5 and at a temperature of 50°C. N-hydroxybenzotriazole, a small molecular weight redox mediator, was found to accelerate the decolorization. Tween 20 inhibited the decolorization while Tween 80 and Brij 35 showed no inhibition effect. Two compounds were identified as the intermediates (m/z 304.3 and m/z 342.2). These results suggest that laccase from Polyporus sp. S133 is a powerful tool for the decolorization of anthraquinone dyes. A pathway for the metabolism of the RBBR by laccase of Polyporus sp S133 was proposed. These proposed pathways could contribute to a better comprehension of the mechanisms used by oxidative enzymes to transform organic compounds. © Springer Science+Business Media B.V. 2011.


Benhelal E.,University of Technology Malaysia | Zahedi G.,University of Technology Malaysia | Shamsaei E.,University of Technology Malaysia | Bahadori A.,Southern Cross University of Australia
Journal of Cleaner Production | Year: 2013

Cement industry has been always among the largest CO2 emission sources. Almost 5e7% of global CO2 emissions are caused by cement plants, while 900 kg CO2 isemitted to the atmosphere for producing one ton of cement. In this work, global strategies and potentials toward mitigation of CO2 emissions in cement plant have beendiscussed and themost promisingapproacheshave beenintroduced.Moreover the barriers against worldwide deployment of such strategies are identified and comprehensively described. Three strategies of CO2 reduction including energysaving, carbon separationandstorage aswell as utilizing alternative materials in detail have been reviewed. In case of energy saving approaches, shifting to more efficient process for example fromwet to dry process with calciner, shows the best results since potentially reduces up to 50% of required energyand mitigates almost20% of CO2emissions in the process. Carbon capture andstorage (CCS) is also considered as an effectiveway to avoid release of CO2. However economical and technical challenges still play a remarkable obstacle against implementing such processes in the cement plant. As far as alternative materials are the case, utilizingwaste-derived fuel (WDF) and industrial by-products instead of conventional fuels and materials result in the significant emission mitigation. Industrial wastes which can be used as both fuel and raw material simultaneously mitigate emissions in cement plants and landfills. © 2013 Elsevier Ltd. All rights reserved.


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.


Sanei S.,University of Surrey | Lee T.K.M.,University of Technology Malaysia | Abolghasemi V.,University of Technology Malaysia
IEEE Transactions on Biomedical Engineering | Year: 2012

Original adaptive line enhancer (ALE) is used for denoising periodic signals from white noise. ALE, however, relies mainly on second order similarity between the signal and its delayed version and is more effective when the signal is narrowband. A new ALE based on singular spectrum analysis (SSA) is proposed here. In this approach in the reconstruction stage of SSA, the eigentriples are adaptively selected (filtered) using the delayed version of the data. Unlike the conventional ALE where (second) order statistics are taken into account, here the full eigen-spectrum of the embedding matrix is exploited. Consequently, the system works for non-Gaussian noise and wideband periodic signals. By performing some experiments on synthetic signals it is demonstrated that the proposed system is very effective for separation of biomedical data, which often have some periodic or quasi-periodic components, such as EMG affected by ECG artefacts. This data are examined here. © 2006 IEEE.


Moser I.,Swinburne University of Technology | Chiong R.,University of Technology Malaysia
Memetic Computing | Year: 2010

Dynamic function optimisation is an important research area because many real-world problems are inherently dynamic in nature. Over the years, a wide variety of algorithms have been proposed to solve dynamic optimisation problems, and many of these algorithms have used the Moving Peaks (MP) benchmark to test their own capabilities against other approaches. This paper presents a detailed account of our hybridised Extremal Optimisation (EO) approach that has achieved hitherto unsurpassed results on the three standardised scenarios of the MP problem. Several different components are used in the hybrid EO, and it has been shown that a large proportion of the quality of its outstanding performance is due to the local search component. In this paper, the behaviour of the local search algorithms used is analysed, and the roles of other components are discussed. In the concluding remarks, the generalisation ability of this method and its wider applicability are highlighted. © Springer-Verlag 2009.


Bin Mamat R.,University of Technology Malaysia
Procedia Engineering | Year: 2012

This paper presents an overview of Proportional Integral control (PI) and Artificial Intelligent control (AI) algorithms. AI and PI controller are analyzed using Matlab [Simulink] software. The DC motor is an attractive piece of equipment in many industrial applications requiring variable speed and load characteristics due to its ease of controllability. The main objective of this paper illustrates how the speed of the DC motor can be controlled using different controllers. The simulation results demonstrate that the responses of DC motor with an AI control which is Fuzzy Logic Control shows satisfactory well damped control performance. The results shows that Industrial DC Motor model develop using its physical parameters and controlled with an AI controller give better response, it means it can used as a controller to the real time DC Motor. © 2012 The Authors.


Kamar H.M.,University of Technology Malaysia | Kamsah N.B.,University of Technology Malaysia | Mohamad Mustafa A.F.,University of Technology Malaysia
Applied Thermal Engineering | Year: 2013

In this study, ANN model for a standard air-conditioning system for a passenger car was developed to predict the cooling capacity, compressor power input and the coefficient of performance (COP) of the automotive air-conditioning (AAC) system. This paper describes the development of an experimental rig for generating the required data. The experimental rig was operated at steady-state conditions while varying the compressor speed, air temperature at evaporator inlet, air temperature at condenser inlet and air velocity at evaporator inlet. Using these data, the network using Lavenberg-Marquardt (LM) variant was optimized for 4-3-3 (neurons in input-hidden-output layers) configuration. The developed ANN model for the AAC system shows good performance with an error index in the range of 0.65-1.65%, mean square error (MSE) between 1.09 × 10-5 and 9.05 × 10-5 and the root mean square error (RMSE) in the range of 0.33-0.95%. Moreover, the correlation which relates the predicted outputs of the ANN model to the experimental results has a high coefficient in predicting the AAC system performance. © 2012 Elsevier Ltd. All rights reserved.


Mohammed Y.S.,University of Technology Malaysia | Mustafa M.W.,University of Technology Malaysia | Bashir N.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

Rising concerns about global energy security and climate change due to emissions of noxious gases resulting from the combustion of fossil fuels have strongly renewed interest in renewable energy development. These concerns have also coordinated a reaction towards the global focus on a clean development mechanism, which is a basic strategy endorsed in the framework of the Kyoto Protocol. The use of biomass for the sustainable distributed generation of power offers immense hope to rural dwellers, who have limited access to electricity from centralized grid systems. Like other renewable sources of energy, biomass distributed-generation systems will play a critical role in the future of electrical power demand outlooks and energy generation planning. This article presents the wide-ranging potential of bioenergy resources in Nigeria for bioelectric power generation. It explicates the poor energy situation of the country and highlights different categories of biomass that can be exploited to tackle the energy deficiency in many rural communities. The study concludes with a discussion on the significance of distributed-generation electricity using bioenergy resources for rural energy supply, including brief discussions on the technologies for bioelectric power utilization. © 2014 Elsevier Ltd.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2011

Diversification of fuel sources is imperative to address the energy security, climate change, and sustainable development issues; therefore, it is essential to address the energy crisis through the extensive utilization of abundant renewable energy resources, such as biomass energy, solar energy, wind energy and geothermal energy. Improving energy services for poor households in developing countries remains one of the most pressing challenges facing the development community. Earlier studies suggest in South Asia the households are likely to follow the energy ladder comprising fuels like dung, crop residue, firewood, kerosene, gobar gas, LPG, and electricity for cooking purposes. Evidence suggests that while it is possible to observe such transition in urban and semi-urban areas, the change is very slow in rural areas. In rural Pakistan, the access to commercial energy resources is limited, the majority of the households still heavily rely on traditional methods of using wood, animal waste and crop waste for domestic fuel needs. Efficiencies of use are very low and most of the potential is wasted because of non-scientific conventional technologies. Consequently there is an obligatory need to develop modern bio-energy technologies since renewable resources may serve to supplement the long-term energy needs of Pakistan to a significant level. Though the bio-resource base of Pakistan is substantial, its contribution to useful energy is low. In this paper we called attention to issues and challenges in biomass utilization for energy in Pakistan in context of sustainable development. This paper has identified areas in Pakistan where there is considerable scope to modernize biomass energy production delivery systems to provide varied energy carriers such as electricity, industrial and domestic fuel and gases. Barriers are examined over the whole biomass energy spectrum and policy issue and institutional roles and responsibilities are discussed. © 2011 Elsevier Ltd. All rights reserved.


El-Mahallawy M.S.,Arab Academy for Science and Technology | Hashim M.,University of Technology Malaysia
IEEE Geoscience and Remote Sensing Letters | Year: 2013

In this letter, we introduce the utilization of discrete cosine transform (DCT) coefficients as features supplied to the support vector machine (SVM) classifier to identify underground utility material from ground penetrating radar (GPR) imagery. Different types of features, reflected signal amplitudes, and statistical features, combined with the SVM classifier for material identification of underground utilities, are also studied and compared to the DCT-based approach. The system performance is conducted by simulation studies using generated GPR images created by a GPR finite-difference time-domain-based simulator used to develop various acquisition situations by changing the utility material type, position, and size parameters. The efficiency of the proposed technique in material identification is assessed using noisy generated GPR images degraded with speckle noise. Two-dimensional median and adaptive Wiener filters are also examined as a preprocessing step to the studied techniques. Simulation results show that the proposed technique combined with adaptive Wiener filter reveals a good performance regarding the recognition accuracy compared to the other studied techniques in noisy environment. © 2013 IEEE.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-SICA | Phase: NMP.2012.2.2-6 | Award Amount: 5.12M | Year: 2012

Limpid aims at generating new knowledge on photocatalytic materials and processes in order to develop novel depollution treatments with enhanced efficiency and applicability. The main goal of LIMPID is to develop materials and technologies based on the synergic combination of different types of nanoparticles (NPs) into a polymer host to generate innovative nanocomposites which can be actively applied to the catalytic degradation of pollutants and bacteria, both in air or in aqueous solution. Single component nanocomposites including TiO2 NPs are already known for their photocatalytic activities. LIMPID will aim at going one big step further and include, into one nanocomposite material, oxide NPs and metal NPs in order to increase the photocatalytic efficiency and allow the use of solar energy to activate the process. One of the main challenge of LIMPID is to design host polymers, such as hybrid organic inorganic and fluorinated polymers, since photocatalysts can destroy the organic materials. The incorporation of NPs in polymers will allow to make available the peculiar nano-object properties and to merge the distinct components into a new original class of catalysts. At the same time nanocomposite formulation will also prevent NPs to leach into water and air phase, thus strongly limiting the potential threat associated to dispersion of NPs into the environment. Therefore nanocomposites developed in LIMPID will be used as coating materials and products for the catalytic degradation of pollutants and bacteria in water and air, i.e. deposited onto re-usable micro-particles, or in pollutant degradation reactors, and even onto large surfaces, as a coating or paint. In addition such new class of nanocomposites will be also exploited for the fabrication of porous membranes for water treatment. In order to fulfill its objectives, the LIMPID consortium has been designed to combine leading industrial partners with research groups from Europe, ASEAN Countries and Canada.


Al-Mulali U.,Multimedia University | Weng-Wai C.,University of Technology Malaysia | Sheau-Ting L.,University of Technology Malaysia | Mohammed A.H.,University of Technology Malaysia
Ecological Indicators | Year: 2015

This study investigates the environmental Kuznets curve (EKC) hypothesis using a country's ecological footprint as an indicator of environmental degradation. Ninety-three countries were examined, categorized by income. The fixed effects and the generalized method of moments results clearly showed an inverted U-shaped relationship between the ecological footprint and GDP growth, which represents the EKC hypothesis in upper middle- and high-income countries but not in low- and lower middle-income countries. This relationship only occurs in a stage of economic development in which technologies are available that improve energy efficiency, energy saving and renewable energy, which are not accessible for countries with low income due to their high cost. Moreover, energy consumption, urbanization, and trade openness increase environmental damage through their positive effect on the ecological footprint of most countries across all income groups. However, financial development reduces environmental degradation in lower middle-, upper middle- and high-income countries. This relationship confirms that loans from banks are primarily given to firms that establish investments in projects that are mostly environmentally friendly. From the results of this study, a number of recommendations can be provided for the investigated countries. © 2014 Elsevier Ltd.


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

Nano-scale materials can be designed to exhibit novel and significantly improved physical and chemical properties. Polymer nanofibers, an important class of nano-materials, have attracted increasing attention in the last 10 years because of their high surface-to-mass (or volume) ratio and special characteristics attractive for advanced applications. In particular, electro-spun nanofiber membranes (ENMs) have high porosity, interconnected open pore structure and tailorable membrane thickness. Moreover, their high surface hydrophobicity makes them suitable for membrane distillation (MD). In this paper, recent progresses are reviewed on the preparation of different types of nanofibers with different secondary nanostructures, including hollow nanofibers. Applications of hollow nanofibers for membrane separation processes are then discussed based on an imaginary design of hollow nanofiber module. Application of ENMs in MD is, on the other hand, not a product of imagination but experiments have already been conducted in various laboratories, as reviewed in this paper. In particular, the experimental results obtained in our laboratory for desalination of saline water and gases stripping of VOCs are highlighted. By using an electrospun PVDF nanofiber membrane, saline water with NaCl content of 6% was successfully desalinated for more than 20 days with no indication of membrane wetting. The PVDF ENM could also be successfully used in gas-stripping of chloroform, representing VOCs, with mass transfer coefficients higher than hollow fiber membranes. It is expected that MD by ENMs can be applied for many other purposes such as waste water treatment, food processing, and treatment of pharmaceutical products. © 2012 Elsevier B.V. All rights reserved.


Noshadi I.,University of Technology Malaysia | Noshadi I.,University of Connecticut | Amin N.A.S.,University of Technology Malaysia | Parnas R.S.,University of Connecticut
Fuel | Year: 2012

This study aims to develop an optimal continuous process to produce fatty acid methyl esters (biodiesel) from waste cooking oil in a reactive distillation column catalyzed by a heteropolyacid, H 3PW 12O 40·6H 2O. The conventional production of biodiesel in the batch reactor has some disadvantage such as excessive alcohol demand, short catalyst life and high production cost. Reactive distillation combines reaction and separation to simplify the process operation. The reaction catalyzed by H 3PW 12O 40·6H 2O overcomes the neutralization problem that occurs in conventional transesterification of waste cooking oil with high free fatty acid (FFAs) and water content. Response surface methodology (RSM) based on central composite design (CCD) was used to design the experiment and analyzed four operating parameters: total feed flow, feed temperature, reboiler duty and methanol/oil ratio. The optimum conditions were determined to be 116.23 (mol/h) total feed flow, 29.9°C feed temperature, 1.3 kW reboiler duty, and 67.9 methanol/oil ratio. The optimum and actual free fatty acid methyl ester (FAME) yield was 93.98% and 93.94%, respectively, which demonstrates that RSM is an accurate method for the current procedure. © 2011 Elsevier Ltd. 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.


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.


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.


Liew P.Y.,University of Technology Malaysia | Lim J.S.,University of Technology Malaysia | Wan Alwi S.R.,University of Technology Malaysia | Abdul Manan Z.,University of Technology Malaysia | And 2 more authors.
Applied Energy | Year: 2014

Heat Pinch Analysis retrofit projects are typically performed by evaluating and maximising the heat recovery potentials within the individual process units. Once the potential improvements from the individual units have been assessed, the Total Site (TS) Heat Integration analysis is performed. Such approach may steer designers away from the promising retrofit opportunities and to lead towards suboptimal heat exchanger networks (HEN). This paper presents an effective retrofit framework for a TS system to determine the most cost-effective retrofit options and maximise the potential savings. Instead of performing the typical unit-wise process retrofit, the strategy is to determine the baseline total site consumption and benchmark targets, and to identify retrofit options from the TS context. This TS retrofit framework has been tested on a case study involving a petrochemical plant comprising of multiple process sections. The results of the analysis show that significant energy savings can be realised when both direct and indirect heat recovery retrofit options are evaluated. Further energy savings can be achieved via the Plus-Minus Principle that helps pinpoint the correct locations of heat surpluses and deficits and lead to the appropriate TS retrofit solution. As a conclusion, energy retrofit projects should be approached from the TS context, followed by the unit-wise retrofit (i.e., retrofit of the individual process sections). © 2014 Elsevier 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.


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.


Jaliliannosrati H.,University of Technology Malaysia | Amin N.A.S.,University of Technology Malaysia | Talebian-Kiakalaieh A.,University of Technology Malaysia | Noshadi I.,University of Connecticut
Bioresource Technology | Year: 2013

The synthesis of fatty acid ethyl esters (FAEEs) by a two-step in situ (reactive) esterification/transesterification from Jatropha curcas L. (JCL) seeds using microwave system has been investigated. Free fatty acid was reduced from 14% to less than 1% in the first step using H2SO4 as acid catalyst after 35min of microwave irradiation heating. The organic phase in the first step was subjected to a second reaction by adding 5N KOH in ethanol as the basic catalyst. Response surface methodology (RSM) based on central composite design (CCD) was utilized to design the experiments and analyze the influence of process variables (particles seed size, time of irradiation, agitation speed and catalyst loading) on conversion of triglycerides (TGs) in the second step. The highest triglycerides conversion to fatty acid ethyl esters (FAEEs) was 97.29% at the optimum conditions:<0.5mm seed size, 12.21min irradiation time, 8.15ml KOH catalyst loading and 331.52rpm agitation speed in the 110W microwave power system. © 2013 Elsevier Ltd.


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.


Yousif B.F.,University of Southern Queensland | Nirmal U.,Multimedia University | Wong K.J.,University of Technology Malaysia
Materials and Design | Year: 2010

This work aims to investigate the wear and frictional behaviour of a new epoxy composite based on treated betelnut fibres subjected to three-body abrasion using different abrasive particle sizes (500μm, 714μm and 1430μm) and sliding velocities (0.026-0.115ms-1) at constant applied load (5N) using a newly developed Linear Tribo Machine. The worn surfaces of the composite were studied using scanning electron microscope. The work revealed that the predominant wear mechanism of treated betelnut fibre reinforced epoxy (T-BFRE) composite sliding against grain sands was plastic deformation, pitting and pullout of betelnut fibres. The composite exhibited higher values in frictional coefficient when it was subjected against coarse sand. Besides, the abrasive wear of the composite is depending on the size of abrasive particles and sliding velocity. Higher weight loss is noticed at high sliding velocities. The specific wear rate for the composite subjected to three different sand particles follow the order of: coarse>grain>fine sands respectively. © 2010 Elsevier Ltd.


Talebian-Kiakalaieh A.,University of Technology Malaysia | Amin N.A.S.,University of Technology Malaysia | Zarei A.,University of Technology Malaysia | Noshadi I.,University of Connecticut
Applied Energy | Year: 2013

Transesterification of waste cooking oil with heterogeneous (heteropoly acid) catalyst and methanol has been investigated. Response Surface Methodology (RSM) and Artificial Neural Network (ANN) were employed to study the relationship between process variables and free fatty acid conversion and for predicting the optimal parameters. The highest conversion was 88.6% at optimum condition being 14h, 65°C, 70:1 and 10wt% for reaction time, reaction temperature, methanol to oil molar ratio and catalyst loading, respectively. The RSM and ANN could accurately predict the experimental results, with R2=0.9987 and R2=0.985, respectively. Kinetics studies were investigated to describe the system. The reaction followed first-order kinetics with the calculated activation energy, Ea=53.99kJ/mol while the pre-exponential factor, A=2.9×107min-1. These findings can help improve an environmentally friendly biodiesel process that conforms to ASTM D6751 standards. © 2012 Elsevier Ltd.


Mohammad Rozali N.E.,University of Technology Malaysia | Wan Alwi S.R.,University of Technology Malaysia | Abdul Manan Z.,University of Technology Malaysia | Klemes J.J.,University of Pannonia | Hassan M.Y.,University of Technology Malaysia
Energy | Year: 2013

The application of Process Integration using the Pinch Analysis technique has been recently extended to the design of hybrid power systems to determine the maximum power recovery and the battery storage capacity. The graphical and the numerical Power Pinch Analysis (PoPA) tools provide designers with visualisation tools that are systematic and simple to implement for the optimisation of power systems. However, the power losses incurred in the systems, have so far, not been considered in detail in the previous works. This paper extends the PoPA method by considering the power losses that occur during the power system's conversion, transfer and storage. The effects of the losses on the minimum outsourced electricity targets and the storage capacity are evaluated. The Storage Cascade Table (SCT) of PoPA has been further developed to include the effect of energy losses in the system's design. Application of the developed method on a case study yields the more realistic power targets for off-grid hybrid power systems. © 2013 Elsevier Ltd.


Foo D.C.Y.,University of Selangor | Tan R.R.,De La Salle University - Manila | Lam H.L.,University of Selangor | Abdul Aziz M.K.,University of Technology Malaysia | Klemes J.J.,University of Pannonia
Energy | Year: 2013

EFB (Empty fruit bunch) is among the palm oil biomass residues that have been identified as the most abundant bioenergy resources in Southeast Asia. EFB has a good potential to meet the targeted share of renewable energy in this region. This work presents robust LP (linear programming) model to allow for the synthesis of EFB allocation networks that exhibit operational flexibility under multiple biomass supply scenarios. Such multiple scenarios may arise due to many uncertain factors, such as anticipated closure or expansion of mills. A MILP (mixed integer linear programming) extension of the model is then developed. Real life-based case studies of an industrial application are presented to illustrate the use of both variants of the model. © 2013 Elsevier Ltd.


Moein S.,Multimedia University | Logeswaran R.,Multimedia University | Logeswaran R.,University of Technology Malaysia
Information Sciences | Year: 2014

Swarm-based algorithms have acquired an important role in solving real-world optimization problems. In this paper, Kinetic Gas Molecule Optimization (KGMO), an optimization algorithm that is based on the kinetic energy of gas molecules, is introduced. The agents are gas molecules that are moving in the search space; they are subject to the kinetic theory of gases, which defines the rules for gas molecule interactions in the model. The performance of the proposed algorithm, in terms of its ability to find the global minima of 23 nonlinear benchmark functions, is evaluated against the corresponding results of two well-known benchmark algorithms, namely, Particle Swarm Optimization (PSO) and the recently developed high-performance Gravitational Search Algorithm (GSA). The simulations that were undertaken indicate that KGMO achieves better results in decreasing the Mean Square Error (MSE). Significant improvements of up to 107 and 1020 times were achieved by KGMO against PSO and GSA, respectively, in solving unimodal benchmark functions within 150 iterations. Improvements of at least tenfold were achieved in solving the multimodal benchmark functions. The proposed algorithm is more accurate and converges faster than does the benchmark algorithms, which makes this algorithm especially useful in solving complex optimization problems. © 2014 Elsevier Inc. All rights reserved.


Wan Alwi S.R.,University of Technology Malaysia | Mohammad Rozali N.E.,University of Technology Malaysia | Abdul-Manan Z.,University of Technology Malaysia | Klemes J.J.,University of Pannonia
Energy | Year: 2012

Pinch Analysis is a well-established methodology of Process Integration for designing optimal networks for recovery and conservation of resources such as heat, mass, water, carbon, gas, properties and solid materials for more than four decades. However its application to power systems analysis still needs development. This paper extends the Pinch Analysis concept used in Process Integration to determine the minimum electricity targets for systems comprising hybrid renewable energy sources. PoPA (Power Pinch Analysis) tools described in this paper include graphical techniques to determine the minimum target for outsourced electricity and the amount of excess electricity for storage during start up and normal operations. The PoPA tools can be used by energy managers, electrical and power engineers and decision makers involved in the design of hybrid power systems. © 2012 Elsevier Ltd.


Al-Mulali U.,Multimedia University | Saboori B.,University of Technology Malaysia | Ozturk I.,Cag University
Energy Policy | Year: 2015

This study investigates the existence of the environmental Kuznets curve (EKC) hypothesis in Vietnam during the period 1981-2011. To realize the goals of this study, a pollution model was established applying the Autoregressive Distributed Lag (ARDL) methodology. The results revealed that the pollution haven hypothesis does exist in Vietnam because capital increases pollution. In addition, imports also increase pollution which indicates that most of Vietnam's imported products are energy intensive and highly polluted. However, exports have no effect on pollution which indicates that the level of exports is not significant enough to affect pollution. Moreover, fossil fuel energy consumption increases pollution while renewable energy consumption has no significant effect in reducing pollution. Furthermore, labor force reduces pollution since most of Vietnam's labor force is in the agricultural and services sectors which are less energy intensive than the industrial sector. Based on the obtained results, the EKC hypothesis does not exist because the relationship between GDP and pollution is positive in both the short and long run. © 2014 Elsevier Ltd.


Chew K.H.,University of Technology Malaysia | Klemes J.J.,University of Pannonia | Alwi S.R.W.,University of Technology Malaysia | Abdul Manan Z.,University of Technology Malaysia
Applied Thermal Engineering | Year: 2013

Heat Integration has been a well-established energy conservation strategy in the industry. Total Site Heat Integration (TSHI) has received growing interest since its inception in the 90s. The methodology has been used with certain simplifications to solve TSHI problems. This paper investigates the main issues that can influence the practical implementation of TSHI in the industry. The main aim is to provide an assessment and possible guidance for future development and extension of the TSHI methodology from the industrial perspective. Several key issues have been identified as being of vital importance for the industries: design, operation, reliability/availability/ maintenance, regulatory/policy and economics. Design issues to consider include plant layout, pressure drop, etc. For operation, issues such as startup and shutdown need to be considered. Reliability, availability and maintenance (RAM) are important as they directly affect the production. Relevant government policy and incentives are also important when considering the options for TSHI. Finally, a TSHI system needs to be economically viable. This paper highlights the key issues to be considered for a successful implementation of TSHI. The impacts of these issues on TS integration are summarised in a matrix, which forms a basis for an improved and closer-to-real-life implementation of the TSHI methodology. © 2013 Elsevier Ltd. All rights reserved.


Sabet M.,University Technology of MARA | Hassan A.,University of Technology Malaysia | Ratnam C.T.,Malaysian Nuclear Agency
Polymer Degradation and Stability | Year: 2012

The mechanical test showed that upon irradiation, the tensile strength (TS) values of the EVA/LDPE blends increased with the addition of EVA. A gradual increase in gel content (GC) and tensile strength (TS) with a concomitant decline in elongation at break (EB) and hot set (HS) were observed upon electron beam irradiation of the blends. The densities of all compounds were found to reduce with irradiation. The melt flow index test (MFI) results revealed that addition of ATH and MH reduced the flowability and addition of EVA improved the processability of the LDPE/EVA blend compounds. The TS of the LDPE/EVA blends deteriorated with the addition of flame retardants. The thermal stability and flame behavior of the halogen free flame retarded composites were studied by thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimeter. The TGA results revealed that the decomposition temperatures of water evolved from the compounds incorporated with MH were significantly higher than that of ATH (i.e. 218-560 °C versus 310-610 °C). The minimum smoke density generation during the combustion obtained with 30% EVA content at both ATH and MH blends. The electrical test showed that the volume resistivity (VR) of the EVA/LDPE blends decreased with increase of EVA, ATH and MH contents, whereas, it declined with increasing irradiation dose. Consequently, this study demonstrated that addition of MH to the irradiated EVA/LDPE blends resulted higher thermal stability, better flammable retardancy, electrical and mechanical properties than addition ATH to the irradiated blends for wire and cable applications. © 2012 Elsevier Ltd. All rights reserved.


Liew P.Y.,University of Technology Malaysia | Wan Alwi S.R.,University of Technology Malaysia | Varbanov P.S.,University of Pannonia | Manan Z.A.,University of Technology Malaysia | Klemes J.J.,University of Pannonia
Applied Thermal Engineering | Year: 2012

Total Site Heat Integration (TSHI) is a methodology for the integration of heat recovery among multiple processes and/or plants interconnected by common utilities on a site. Until now, it has not been used to analyze a site's overall sensitivity to plant maintenance shutdown and production changes. This feature is vital for allowing engineers to assess the sensitivity of a whole site with respect to operational changes, to determine the optimum utility generation system size, to assess the need for backup piping, to estimate the amount of external utilities that must be bought and stored, and to assess the impact of sensitivity changes on a cogeneration system. This study presents four new contributions: (1) Total Site Sensitivity Table (TSST), a tool for exploring the effects of plant shutdown or production changes on heat distribution and utility generation systems over a Total Site; (2) a new numerical tool for TSHI, the Total Site Problem Table Algorithm (TS-PTA), which extends the well-established Problem Table Algorithm (PTA) to Total Site analysis; (3) a simple new method for calculating multiple utility levels in both the PTA and TS-PTA; and (4) the Total Site Utility Distribution (TSUD) table, which can be used to design a Total Site utility distribution network. These key contributions are clearly highlighted via the application of the numerical technique to two Case studies. © 2012 Elsevier Ltd. All rights reserved.


Alavi S.E.,University of Technology Malaysia | Amiri I.S.,University of Technology Malaysia | Idrus S.M.,University of Technology Malaysia | Supa'at A.S.M.,University of Technology Malaysia | And 2 more authors.
IEEE Photonics Journal | Year: 2014

The optical carrier generation is the basic building block to implement all-optical orthogonal frequency-division multiplexing (OFDM) transmission. One method to optically generate single and multicarriers is to use the microring resonator (MRR). The MRRs can be used as filter devices, where generation of high-frequency (GHz) soliton signals as single and multicarriers can be performed using suitable system parameters. Here, the optical soliton in a nonlinear fiber MRR system is analyzed, using a modified add/drop system known as a Panda ring resonator connected to an add/drop system. In order to set up a transmission system, i.e., IEEE802.11a, first, 64 uniform optical carriers were generated and separated by a splitter and modulated; afterward, the spectra of the modulated optical subcarriers are overlapped, which results one optical OFDM channel band. The quadrature amplitude modulation (QAM) and 16-QAM are used for modulating the subcarriers. The generated OFDM signal is multiplexed with a single-carrier soliton and transmitted through the single-mode fiber (SMF). After photodetection, the radio frequency (RF) signal was propagated. On the receiver side, the RF signal was optically modulated and processed. The results show the generation of 64 multicarriers evenly spaced in the range from 54.09 to 55.01 GHz, where demodulation of these signals is performed, and the performance of the system is analyzed. © 2009-2012 IEEE.


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.


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.


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.


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.


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.


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.


Lim S.K.,University Tunku Abdul Rahman | Tan C.S.,University of Technology Malaysia | Lim O.Y.,University Tunku Abdul Rahman | Lee Y.L.,University of Technology Malaysia
Construction and Building Materials | Year: 2013

Incorporation of pozzolans can give useful enhancements to the concrete properties. This paper aims to study the effects of palm oil fuel ash (POFA) on engineering properties of lightweight foamed concrete (LFC) with 1300 ± 50 kg/m3 of density in terms of compressive, splitting tensile and flexural strengths, compressive toughness, and thermal conductivity. Three types of LFC were prepared, namely (i) LFC with 100% sand filler as control mix (LFC-CM), (ii) LFC with 10% POFA replacement as a part of filler (LFC-PF10) and (iii) LFC with 20% POFA replacement as a part of filler (LFC-PF20). All specimens were under water curing condition. It was observed that the incorporation POFA into foamed concrete as a part of filler for LFC-PF10 and LFC-PF20 has enhanced their compressive strength, flexural and splitting tensile strengths, ductility as well as compressive toughness. Besides, the thermal conductivity of POFA based LFC specimens were slightly increased compared to that of control LFC specimens. It is demonstrated that lightweight foamed concretes with certain percentage of POFA replacement filler (LFC-PF10 and LFC-PF20) obtained better strengths performance compared to the controlled specimens (LFC-CM) with solely sand filler. © 2013 Elsevier Ltd. All rights reserved.


Yusof N.,Advanced Membrane Research Technology Center | Yusof N.,University of Technology Malaysia | Ismail A.F.,Advanced Membrane Research Technology Center | Ismail A.F.,University of Technology Malaysia
Journal of Analytical and Applied Pyrolysis | Year: 2012

This paper reviews pyrolysis process to convert PAN precursor fiber into PAN-based carbon fiber and activated carbon fiber. The parameters involved during heat treatment of PAN fiber are consistently discussed. Post spinning treatments of PAN fiber are also discussed in this paper as it has a crucial contribution towards the success of pyrolysis processes. Finally, the recent development and future works in research and development are briefly discussed to further extend the boundary of science and technology of PAN-based carbon fiber and activated carbon fiber in order to fully explore its potential. © 2011 Elsevier B.V. All rights reserved.


Chong H.Y.,University Tunku Abdul Rahman | Zin R.M.,University of Technology Malaysia | Chong S.C.,University of Technology Malaysia
Journal of Construction Engineering and Management | Year: 2013

Although data warehouse is very practical for decision making, its application in contract administration is rather limited because of the complicated legal issues and the voluminous data involved. This research attempts to bridge this gap in two ways. First, conceptual models of data warehouse are developed to explain the contents and overall features of the system that were verified by 12 experts in Malaysia. Second, an electronic dispute resolution template, known as e-Dispute Resolution (e-DR), is prototyped by using a database tool based on the guidelines of contractual variations agreed by the experts. Subsequently, the prototype is evaluated by 16 professional quantity surveyors from an established consulting firm. The prototype was organized based on a systematic breakdown of issues and incorporated a Boolean keyword search feature. The results show that the concept of data warehouse is applicable to contract administration and is well received by practitioners. Overall, this article renders significant theoretical and practical contributions in which the resulting e-DR does not only lead toward more informed decision making but is also able to mitigate or prevent contractual disputes in the construction industry, where such a phenomenon seems to be inevitable. © 2013 American Society of Civil Engineers.


Selvakumar M.,Indian Institute of Technology Kharagpur | Jaganathan S.K.,University of Technology Malaysia | Jaganathan S.K.,PSNA College of Engineering and Technology | Nando G.B.,Indian Institute of Technology Kharagpur | Chattopadhyay S.,Indian Institute of Technology Kharagpur
Journal of Biomedical Nanotechnology | Year: 2015

The present investigation reports the preparation of two types of 2D rod-like nano-hydroxyapatite (nHA) (unmodified and Polypropylene glycol (PPG) wrapped) of varying high-aspect ratios, by modified co-precipitation methods, without any templates. These nHA were successfully introduced into novel synthesized Thermoplastic Polyurethane (TPU) matrices based on polycarbonate soft segments, by both in-situ and ex-situ techniques. Physico-mechanical properties of the insitu prepared TPU/nHA nanocomposites were found to be superior compared to the ex-situ counterparts, and pristine nHA reinforced TPU. Improved biocompatibility of the prepared nanocomposites was confirmed by MTT assays using osteoblast-like MG63 cells. Cell proliferation was evident over an extended period. Osteoconductivity of the nanocomposites was observed by successful formation of an apatite layer on the surface of the samples, after immersion into simulated body fluid (SBF). Prothrombin time (PT) and activated partial thromboplastin time (APTT), as calculated from coagulation assays, displayed an increase in the clotting time, particularly for the PPG-wrapped nHA nanocomposites, prepared through the in-situ technique. Only 0.3% of hemolysis was observed for the in-situ prepared nanocomposites, which establishes the antithrombotic property of the material. The key parameters for enhancing the technical properties and biocompatibility of the nanocomposites are: the interfacial adhesion parameter (Bσy ), the polymer-filler affinity, the aspect ratio of filler and non-covalent modifications, and the state of dispersion. Thus, the novel TPU/polymer wrapped nHA nanocomposites have great potential for biomedical applications, in particular for vascular prostheses, cardiovascular implants, scaffolds, and soft and hard tissues implants.


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.


Ismail Z.H.,University of Technology Malaysia | Dunnigan M.W.,Heriot - Watt University
InECCE 2011 - International Conference on Electrical, Control and Computer Engineering | Year: 2011

In this paper, a simple control approach based on a region boundary technique for geometric formation of multiple Autonomous Underwater Vehicles (AUVs) is presented. The control objective is to keep each underwater vehicle at each corner of a desired geometric shape, i.e. an equilateral triangle or a square. An edge-based segmentation approach is utilized rather than specifying the minimum distance between members to ensure that each vehicle is placed exactly at the desired position in their formation. This allows each vehicle that has its own function to carry out an effective individual task, thus improving the formation's performance. The model of the ODIN vehicle is used as an example to demonstrate the proposed controller. Simulation results show the effectiveness of the controllers. © 2011 IEEE.


Shaaban M.,University of Technology Malaysia | Shaaban M.,Port Said University | Petinrin J.O.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

Nigeria is endowed with abundant energy resources, both conventional and renewable, which can potentially provide the country with a sufficient capacity to meet the ambitions of both urban and rural Nigerians of a full, nationwide electrification level. Yet, Nigeria has one of the lowest consumption rates of electricity per capita in Africa. With the demand superseding the generation, there is inequitable access of rural communities to the electricity service in the country. There are inherent obstacles militating against the effective implementation of an orderly energy policy in Nigeria. The inefficiencies overshadowing the allocation of energy resources coupled with the near depletion of fossil fuels, make it imperative for the country to exploit its huge natural renewable resources to avoid a worsening energy supply scenario and provide feasible electricity to rural dwellers. This paper presents a review of renewable energy potentials in Nigeria to be tapped for useful and uninterrupted electric energy supply. The extent of renewable energy resources is described and existing government policies are articulated. Various polices, that could possibly incentivize the realization of wider renewable energy applications in rural Nigeria, are proposed. The challenges and future prospects of renewable energy are also discussed. Dissemination of decentralized renewable energy resources will not only improve the wellbeing of rural Nigerian communities, but also enhance Nigeria's energy and economic prospects for potential global investment. © 2013 Elsevier Ltd.


Chong H.-Y.,University Tunku Abdul Rahman | Zin R.M.,University of Technology Malaysia
Engineering, Construction and Architectural Management | Year: 2012

Purpose -The purpose of this research is to discover the behavior of dispute resolution in the Malaysian construction industry by analyzing factors that affect the selection of dispute resolution methods using factor analysis approach. Design/methodology/approach -Preliminary interviews and a questionnaire survey were conducted. Dispute resolution methods were grouped and discussed together, based on the similarity of their characteristics, and used for the questionnaire survey. This research approach is different from the earlier studies that mostly focused on a single dispute resolution method. The data were further analyzed with factor analysis. This improved the data interpretation. Findings -Seven latent factors were extracted and revealed that the contractors and developers preferred alternative dispute resolution (ADR). However, the appreciation of the outcomes of ADR was perceived to be very low. Arbitration and litigation were in part accepted and agreed upon by the respondents. Originality/value -The combined results from the literature review on the stages of dispute resolution and the latent factors affecting the selection of dispute resolution methods could assist in decision making. The selection of ADR or non-ADR itself is not a major issue; rather, there is a concern for increased efficiency and an appreciation of the methods in the construction industry are more demanding. © Emerald Group Publishing Limited.


Lee L.M.,University Tunku Abdul Rahman | Kassim A.,University of Technology Malaysia | Gofar N.,University of Technology Malaysia
Engineering Geology | Year: 2011

Rainfall infiltration and suction variation in unsaturated soils must be taken into consideration in the analysis of most slope stability problems, particularly in the tropical regions where the annual precipitation is high. The process of rainfall infiltration into unsaturated soils is an extremely complex problem attributed to the non-linearity of the hydraulic property functions of the unsaturated soils. This paper describes in detail two instrumented laboratory models, i.e. one-dimensional soil column, and two-dimensional slope model used to provide experimental evidences for the transient suction variations in the unsaturated soils under certain rainfall conditions. The performances of the laboratory models were tested on four typical types of residual soils, i.e. sand-gravel, silty gravel, sandy silt, and silt (kaolin), and a two-layered soil system, i.e. sandy silt underlain by silty gravel. The results showed that the suction distributions for the single-layered homogeneous soils obtained from the simpler one-dimensional soil column were almost identical to that of two-dimensional slope model. However, the two-dimensional slope model should be employed for the two-layered soil system because of the dominant effect of the lateral flow mechanism. The capillary barrier effect was observed when a less permeable soil layer was underlain by a more permeable soil layer. The minimum suction value in soil is governed by the rainfall intensity, rainfall duration, and the saturated permeability of soil. The infiltration rate of the fine-grained soils that subjected to shrink and crack was independent of the soil permeability, but was significantly governed by the preferential flows developed in the soils. © 2010 Elsevier B.V.


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.


Aliyu A.S.,University of Technology Malaysia | Aliyu A.S.,Nasarawa State University | Ramli A.T.,University of Technology Malaysia
Radiation Measurements | Year: 2015

The residents of the world's high background natural radiation areas (HBNRAs), such as Ramsar (in Iran), Guarapari (in Brazil), Orissa and Kerala (in India) and Yangjiang (in China) have lived in these areas for generations under extraordinary radiation fields. The failure of earlier epidemiological studies to report any substantial increase in cancer incidence in HBNRAs has raised some controversy regarding the validity of the linear no-threshold hypothesis. This paper reviews some of the most recent studies of HBNRAs with the intent of stimulating greater research interest in the dosimetric, epidemiological and radiobiological issues related to the world's HBNRAs and proposes solutions to the challenges facing HBNRA studies. This paper may serve as a useful reference for some of the harder-to-find literature. ©2015 Elsevier Ltd. All rights reserved.


Abdo A.,University of Technology Malaysia | Abdo A.,Hodeidah University | Salim N.,University of Technology Malaysia
Journal of Chemical Information and Modeling | Year: 2011

Many of the conventional similarity methods assume that molecular fragments that do not relate to biological activity carry the same weight as the important ones. One possible approach to this problem is to use the Bayesian inference network (BIN), which models molecules and reference structures as probabilistic inference networks. The relationships between molecules and reference structures in the Bayesian network are encoded using a set of conditional probability distributions, which can be estimated by the fragment weighting function, a function of the frequencies of the fragments in the molecule or the reference structure as well as throughout the collection. The weighting function combines one or more fragment weighting schemes. In this paper, we have investigated five different weighting functions and present a new fragment weighting scheme. Later on, these functions were modified to combine the new weighting scheme. Simulated virtual screening experiments with the MDL Drug Data Report23 and maximum unbiased validation data sets show that the use of new weighting scheme can provide significantly more effective screening when compared with the use of current weighting schemes. © 2011 American Chemical Society.


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

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


Jaganathan S.K.,University of Technology Malaysia | Jaganathan S.K.,PSNA College of Engineering and Technology | Supriyanto E.,University of Technology Malaysia | Mandal M.,Indian Institute of Technology Kharagpur
World Journal of Gastroenterology | Year: 2013

AIM: To investigate the events associated with the apoptotic effect of p -Coumaric acid, one of the phenolic components of honey, in human colorectal carcinoma (HCT-15) cells. METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertazolium- bromide assay was performed to determine the antiproliferative effect of p -Coumaric acid against colon cancer cells. Colony forming assay was conducted to quantify the colony inhibition in HCT 15 and HT 29 colon cancer cells after p -Coumaric acid treatment. Propidium Iodide staining of the HCT 15 cells using flow cytometry was done to study the changes in the cell cycle of treated cells. Identification of apoptosis was done using scanning electron microscope and photomicrograph evaluation of HCT 15 cells after exposing to p -Coumaric acid. Levels of reactive oxygen species (ROS) of HCT 15 cells exposed to p -Coumaric acid was evaluated using 2', 7'-dichlorfluorescein- diacetate. Mitochondrial membrane potential of HCT-15 was assessed using rhodamine-123 with the help of flow cytometry. Lipid layer breaks associated with p -Coumaric acid treatment was quantified using the dye merocyanine 540. Apoptosis was confirmed and quantified using flow cytometric analysis of HCT 15 cells subjected to p -Coumaric acid treatment after staining with YO-PRO-1. RESULTS: Antiproliferative test showed p -Coumaric acid has an inhibitory effect on HCT 15 and HT 29 cells with an IC50 (concentration for 50% inhibition) value of 1400 and 1600 μmol/L respectively. Colony forming assay revealed the time-dependent inhibition of HCT 15 and HT 29 cells subjected to p -Coumaric acid treatment. Propidium iodide staining of treated HCT 15 cells showed increasing accumulation of apoptotic cells (37.45 ± 1.98 vs 1.07 ± 1.01) at sub-G1 phase of the cell cycle after p -Coumaric acid treatment. HCT-15 cells observed with photomicrograph and scanning electron microscope showed the signs of apoptosis like blebbing and shrinkage after p -Coumaric acid exposure. Evaluation of the lipid layer showed increasing lipid layer breaks was associated with the growth inhibition of p -Coumaric acid. A fall in mitochondrial membrane potential and increasing ROS generation was observed in the p -Coumaric acid treated cells. Further apoptosis evaluated by YO-PRO-1 staining also showed the timedependent increase of apoptotic cells after treatment. CONCLUSION: These results depicted that p -Coumaric acid inhibited the growth of colon cancer cells by inducing apoptosis through ROS-mitochondrial pathway. © 2013 Baishideng Publishing Group Co., Limited. All rights reserved.


Chong H.-Y.,University Tunku Abdul Rahman | Zin R.M.,University of Technology Malaysia
International Journal of Project Management | Year: 2010

Different interpretation could denote a dispute regarding the contractual obligations and expectation between the contracting parties. This paper addresses the need for clarity of standard form in Malaysia. Hence the objectives are to identify the problems in the language structure of standard form from the viewpoint of professionals, and the measures for improving the language structure of standard form. The research aims to mitigate or prevent construction disputes through better interpretation and understanding of construction contracts, and it offers a proactive approach to avoid the inevitability of conflicts occurring in a project. The data collection was mainly by questionnaire survey. Two experts from construction contracting were appointed to approve the questionnaire design and verify the research outcomes. The results identified eight clarity aspects and three legalese problems of language structure in PWD 203A (Rev. 10/83) Form. Besides, twelve out of thirteen measures were agreed upon by the respondents as to ways for improving the language structure. It is concluded that clarity needs to be considered in future contract drafting towards the understanding of standard forms, and thereby to contribute to the avoidance of disputes. © 2009 Elsevier Ltd and IPMA.


Amiri I.S.,University of Technology Malaysia | Ali J.,University of Technology Malaysia | Yupapin P.P.,King Mongkut's University of Technology Thonburi
International Journal of Modern Physics B | Year: 2012

We present effect of the input central wavelength on microring resonator (MRR) performance using proposed systems. The first proposed system consists of series of microring resonator incorporated with an add/drop filter system, while the second system uses a PANDA ring resonator connected to an add/drop filter system. These two systems can be used to enhance the free spectrum range (FSR) and finesse (F) of the optical soliton pulses. The FSR and Finesse can be improved by raising the central wavelengths of the input pulse from 0.6 μm to 1.5 μm. This is obtained via the add/drop filter, which is used to increase the channel capacity of the communication networks as well. Simulation results for the first proposed system show that FSR and FWHM of 1530 pm and 50 pm can be obtained when the central wavelength of the input pulse is 1.5 μm. FSR and FWHM of 370 pm and 5 pm are simulated, when the PANDA ring resonator system is used. Therefore Finesse of the systems can be improved to 30.6 and 74 for the first and second proposed system, respectively. © 2012 World Scientific Publishing Company.


Garoosi F.,Semnan University | Rohani B.,University of Technology Malaysia | Rashidi M.M.,Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems | Rashidi M.M.,ENN Group
Powder Technology | Year: 2015

Steady state mixed convection heat transfer of nanofluid in a two-sided lid driven cavity with several pairs of heaters and coolers (HACs) inside is investigated numerically using two-phase mixture model. The governing equations have been discretized using the finite volume method while the SIMPLE algorithm has been introduced to couple the velocity-pressure. The influences of volume fraction, diameter and type of the nanoparticles, Richardson number, number of the Heaters and Coolers (HACs), external and internal heating and moving direction of the cavity walls on flow structure, the heat transfer rate and distribution of nanoparticles are investigated. The results of this investigation illustrate that, at low Richardson number by increasing number of the HACs, the heat transfer rate increases. On the other hand, at high Ri, a saturated number of HACs exists which beyond that the value of mean Nusselt number does not changes significantly. In addition, the results reveal that by reducing the diameter of the nanoparticles and Ri, the heat transfer rate increases. It is also observed that at high Richardson numbers, distribution of nanoparticles with dp≥145nm is fairly non-uniform while at low Richardson numbers particle distribution remains almost uniform. Moreover, it is found that by changing direction of the moving walls the heat transfer rate changes significantly. © 2015 Elsevier B.V.


Kanniah K.D.,University of Technology Malaysia | Beringer J.,Monash University | Hutley L.B.,Charles Darwin University
Progress in Physical Geography | Year: 2013

Studying the temporal pattern of savanna gross primary productivity (GPP) is essential for predicting the response of the biome to global environmental changes. In this study, MODIS satellite data coupled with eddy covariance based flux measurements were used to estimate GPP using a remote sensing based light use efficiency model across a significant rainfall gradient in the Northern Territory (NT) region of Australia. Closed forest that occurred in wet and often fireproof environments assimilated (GPP) 4-6 times more carbon than grasslands and Acacia woodlands that grow in arid environments (<600 mm annual rainfall). However, due to their small spatial extent, closed forests contributed <0.5% of the regional budget compared to savanna woodlands (86%) and grasslands (32%). Annual rainfall was found to exert a significant influence on GPP for different vegetation types except for closed forest which was less sensitive to above-average rainfall. Interannual variability in GPP showed that arid ecosystems had a higher variation (>20%) compared to woodlands and forest (∼5%). This variation in GPP was correlated with that of rainfall (R2 = 0.88, p<0.05). Analysis of the impact of wettest and driest years on GPP showed a strong positive correlation between the magnitude of the relative maxima in rainfall and maxima in GPP (R2 = 0.89, p<0.05). In contrast, the relative rainfall minima exhibited an insignificant relationship with relative GPP minima (R2 = 0.45, p = 0.07). These findings provide valuable information on the carbon uptake across the savanna biome and show the sensitivity of different vegetation systems to rainfall, a variable that may change in quantity and variability with projected climate change. Such data also show regions of high levels of carbon that could be linked with savanna management to protect the resources in the Australian savannas. © The Author(s) 2013.


Habidin N.F.,Sultan Idris University of Education | Yusof S.M.,University of Technology Malaysia
International Journal of Automotive Technology | Year: 2012

In the globalization era, lean initiatives and environmental management systems are increasingly implemented in the automotive industry. The aim of this report is to investigate and perform structural analysis of Lean Six Sigma (LSS) and Organizational Performance (OP). Data were obtained from 252 top management leaders in the Malaysian automotive industry. This report presents the results of the Exploratory Factor Analyses (EFA), Confirmatory Factor Analysis (CFA), and reliability analysis, which are empirically verified and validated. A set of assessment measurements of LSS and OP is expected to be suitable for their characteristics and improve their competitiveness. Thus, the main objective of the analysis was to provide additional insight into the relationship between LSS and OP by examining the effects of ISO 14001 certification as a moderator. The results indicate that ISO 14001 certification does not significantly moderate the relationship between LSS and OP in the Malaysian automotive industry. However, the OP values for ISO 14001 certified companies are higher than those without ISO 14001 certification. © 2012 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.


Mohammed H.A.,University of Technology Malaysia | Abbas A.K.,University of Kerbala | Sheriff J.M.,University of Technology Malaysia
International Communications in Heat and Mass Transfer | Year: 2013

A numerical investigation is performed to study the effects of different geometrical parameters on the thermal and flow fields through transversely corrugated circular tubes with Reynolds number ranging from 5000 to 60,000 and heat flux of 50W/cm2. The optimization through nineteen transversely corrugated (roughened) tubes having 10mm inner diameter was studied by changing the dimensions of roughness such as relative roughness height (e/d) in the range of 0.025-0.1, relative roughness pitch (p/d) in the range of 0.5-1.5 and relative roughness width (w/d) in the range of 0.05-0.2. For water as a working fluid, heat transfer can be increased with optimal roughness dimensions and maximum performance evaluation criterion (PEC). The results show that the corrugated tube performance was greatly influenced by the geometrical parameters. The Nusselt number increased as the roughness height, width and Reynolds number increased and with the decrease of roughness pitch. The highest Nusselt number was obtained with e/d=0.1, while the efficient flow (max. PEC) was achieved with e/d=0.025 for p/d=0.5 and w/d=0.2. For the rib-roughened tubes, the influence of Reynolds number on the friction factor is quite weak while it is increased with the increase of roughness height compared with the smooth tube. © 2013 Elsevier Ltd.


Mahdi R.A.,University of Tenaga Nasional | Mahdi R.A.,University of Technology Malaysia | Mohammed H.A.,University of Technology Malaysia | Munisamy K.M.,University of Tenaga Nasional | Saeid N.H.,Brunei Institute of Technology
Renewable and Sustainable Energy Reviews | Year: 2015

There are two advantages of using porous media. First, its dissipation area is greater than the conventional fins that enhances the heat convection. Second is the irregular motion of the fluid flow around the individual beads which mixes the fluid more effectively. Nanofluids result from the mixtures of base fluid with nanoparticles having dimensions of (1-100) nm, with very high thermal conductivities; as a result, it would be the best convection heat transfer by using two applications together: porous media and nanofluids. This article aims to summarize the published articles in respect to porosity, permeability (K) and inertia coefficient (Cf) and effective thermal conductivity (keff) for porous media, also on the thermophysical properties of nanofluid and the studies on convection heat transfer in porous media with nanofluid. © 2014 Elsevier Ltd.


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.


Al Gizi A.J.H.,University of Technology Malaysia | Mustafa M.W.,Foundation of Technical Education Baghdad | Jebur H.H.,University of Technology Malaysia
Applied Soft Computing Journal | Year: 2014

A hybrid model is designed by combining the genetic algorithm (GA), radial basis function neural network (RBF-NN) and Sugeno fuzzy logic to determine the optimal parameters of a proportional-integral-derivative (PID) controller. Our approach used the rule base of the Sugeno fuzzy system and fuzzy PID controller of the automatic voltage regulator (AVR) to improve the system sensitive response. The rule base is developed by proposing a feature extraction for genetic neural fuzzy PID controller through integrating the GA with radial basis function neural network. The GNFPID controller is found to possess excellent features of easy implementation, stable convergence characteristic, good computational efficiency and high-quality solution. Our simulation provides high sensitive response (∼0.005 s) of an AVR system compared to the real-code genetic algorithm (RGA), a linear-quadratic regulator (LQR) method and GA. We assert that GNFPID is highly efficient and robust in improving the sensitive response of an AVR system. © 2014 Elsevier B.V. All rights reserved.


Adhami B.,Islamic Azad University at Tehran | Niroumand H.,University of Technology Malaysia | Khanlari K.,Islamic Azad University at Tehran
Advanced Materials Research | Year: 2012

In general terms, the aim of "System Identification" is to determine the dynamic characteristics of mechanical systems. These characteristics include both frequency characteristics (frequencies, mode shapes, and damping ratios) and the system's characteristic matrices (the matrices of mass, viscous damping, stiffness, Coulomb damping or coefficients of friction, and the Duffing stiffness). In such fields as "Damage Detection" in structures, identification of the system's characteristic matrices is of the same importance as the identification of the frequency characteristics, or even more so, by identifying these matrices, the intended goals in Damage Detection can be achieved. In line with such identification, a new algorithm for the system identification of shear structures is presented in the paper. Taking into account the fundamental and significant effect of noise attenuation in boosting the levels of precision and the correctness of system identification, this method helps to achieve noise attenuation by trimming noisy records in the frequency domain, in parallel with the identification of the structural system. The efficiency and precision of the method have been examined through the application of a "closed loop solution" to a five storey model of shear structure. © (2012) Trans Tech Publications.


Bahadoran M.,University of Technology Malaysia | Ali J.,University of Technology Malaysia | Yupapin P.P.,King Mongkut's University of Technology Thonburi
IEEE Photonics Technology Letters | Year: 2013

Nonlinear response of light such as bistability, the Ikeda instability and the dynamics of light within InGaAsP-InP-modified add-drop resonator (PANDA Vernier resonator) is studied. The signal flow graph method is used to obtain the optical transfer function. Invariant and symmetric coupling coefficients R=kL=0.25 for indirect couplers are applied and the effect of changing symmetric direct couplers (K1=K2) for two different resonant mode numbers is studied. The minimum drop port switching time of 2.83 ps and 2.87 ps for resonant mode numbers of 7;5;5 and 4;3;3 are achieved, respectively. The simulated results introduce the PANDA Vernier system as a proper optical device for future optical communication and signal processing systems. © 1989-2012 IEEE.


Bahadoran M.,University of Technology Malaysia | Ali J.,University of Technology Malaysia | Yupapin P.P.,King Mongkut's University of Technology Thonburi
Applied Optics | Year: 2013

In this paper, the bifurcation behavior of light in the PANDA ring resonator is investigated using the signal flow graph (SFG) method, where the optical transfer function for the through and drop ports of the PANDA Vernier system are derived. The optical nonlinear phenomena, such as bistability, Ikeda instability, and dynamics of light in the silicon-on-insulator (SOI) PANDA ring resonator with four couplers are studied. The transmission curves for bistability and instability as a function of the resonant mode numbers and coupling coefficients for the coupler are derived by the SFG method and simulated. The proposed system has an advantage as no optical pumping component is required. Simulated results show that closed-loop bistable switching can be generated and achieved by varying mode resonant numbers in the SOI-PANDA Vernier resonator, where a smooth and closed-loop bistable switching with low relative output/input power can be obtained and realized. The minimum through-port switching time of 1.1 ps for resonant mode numbers of 5;4;4 and minimum drop port switching time of 1.96 ps for resonant mode numbers of 9;7;7 of the PANDA Vernier resonator are achieved, which makes the PANDA Vernier resonator an operative component for optical applications, such as optical signal processing and a fast switching key in photonics integrated circuits. ©2013 Optical Society of America.


Kasabov N.,Auckland University of Technology | Hamed H.N.A.,University of Technology Malaysia
International Journal of Artificial Intelligence | Year: 2011

The paper deals with feature (variable) and model parameter optimisation utilising a proposed dynamic quantum-inspired particle swarm optimisation method. In this method the features of the model are represented probabilistically as a quantum bit vector and the model parameter values - as real numbers. The principle of quantum superposition is used to accelerate the search for an optimal set of features, that combined through co-evolution with a set of optimised parameter values, will result in an optimal model. The paper applies the method to the problem of feature and parameter optimisation of evolving spiking neural network models. A swarm of particles is used to find the classification model with the best accuracy for a given classification task. The method is illustrated on a bench mark classification problem. The proposed method results in the design of faster and more accurate classification models than the ones optimised with the use of standard evolutionary optimisation algorithms. © 2011 by IJAI.


Bagheri M.,Islamic Azad University at Tehran | Borhani T.N.G.,University of Technology Malaysia | Zahedi G.,University of Technology Malaysia
Energy Conversion and Management | Year: 2012

The combustible nature of organic sulfur containing chemicals demands an accurate hazardous knowledge for their safe handling and application in industries and researches. In this work, a quantitative structure-property relationship (QSPR) study was performed to thoroughly investigate such crucial hazardous properties i.e., flash point (FP) and autoignition temperature (AIT) of the organic sulfur chemicals which are comprising a wide range of mercaptans, sulfides/thiophenes, polyfunctional C,H,O,S material classes. Based on multivariate linear regression (MLR) the multivariate model was gained using a robust binary particle swarm optimization (PSO) for the feature selection step, the three molecular descriptors were realized as the most responsible descriptors for the flammability behaviors of such chemicals. Next, a three-layer feed-forward neural network model (ANN model) was utilized. The implemented multivariate linear regression and three-layer feed-forward neural network models were practically able to predict the flammability characteristics of a diverse range organic sulfur containing chemicals with high accuracy. The results for PSO-MLR model illustrated that the squared correlation coefficient (R 2) between predicted and experimental values were 0.9286 and 0.9259 for FP and AIT, respectively. The results for ANN model showed that the squared correlation coefficients (R 2) were 0.9858 and 0.9889 for FP and AIT, respectively. The ANN model of FP and AIT is more accurate than the multivariate model, and the PSO-MLR model is more simple and touchable. © 2012 Elsevier Ltd. All rights reserved.


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.


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.


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.


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.


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.


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.


Siswanto E.,University of Technology Malaysia | Ishizaka J.,Nagoya University | Tripathy S.C.,Nagoya University | Miyamura K.,Forestry and Fisheries Research Center
Remote Sensing of Environment | Year: 2013

The end of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) mission makes harmful algal bloom (HAB) detection with moderate resolution satellite data now relies on Moderate Resolution Imaging Spectroradiometer (MODIS). Based on MODIS and in situ data collected in the coastal region of the western part of Seto-Inland Sea, Japan with HAB-forming algae Karenia mikimotoi, a simpler new satellite remote sensing-based HAB detection method was developed. The strength of this method is, although it does not require indigenous atmospheric correction scheme, it is expected to be able to classify K. mikimotoi blooms, diatom blooms, TSM-dominated waters, gelbstoff-dominated waters, and mixed waters in the optically complex coastal waters. We anticipate that our satellite remote sensing-based HAB detection method can operate as a valuable complementary tool assisting in situ HAB monitoring and as an integrated part of HAB early warning systems to mitigate HAB negative impacts not only in the coastal waters of the western part of Seto-Inland Sea, Japan, but also in the other coastal waters with different HAB-forming algae, providing that backscattering signature and pigment packaging of other HAB-forming algae are similar to those of K. mikimotoi. © 2012 Elsevier Inc.


Mahjoub R.,Islamic Azad University | Yatim J.M.,University of Technology Malaysia | Mohd Sam A.R.,University of Technology Malaysia | Hashemi S.H.,Arak University
Construction and Building Materials | Year: 2014

Nowadays, due to environmental concerns and financial problems of synthetic fibers, natural fibers or bio-fibers are interesting to be used as reinforcement fibers in polymer composites for structural elements and construction materials. Chemical surface modification method is a well-known method to increase the interfacial bonding strength between fibers and polymer matrix. The alkaline treatment of kenaf fiber may affect not only the surface but also the texture of fiber resulting in the variation of the mechanical and physical properties. This study was conducted to find out the effects of different conditions of alkaline treatment in terms of the concentration of alkali solution and immersion time on the fiber properties. For this study, 360 fiber specimens were tested for 24 various conditions of initial treatment and alkaline surface modifications. Then, the results were analyzed and reported by using of three methods including regression method, averaging the data and system compliance method. Besides, the scanning electron microscopy was employed to observe the specimens' appearance, fracture area and fibers' diameter. Result from the study found that the average diameter of untreated kenaf fiber was 67.6 μm, the density was 1.2 g/cm3 and the tensile strength was 780 MPa. Moreover, the 5% alkali solution was the best for kenaf fiber treatment because of causing no tension on the fiber texture and structure as compared to 10% and 15% alkali solution. © 2014 Elsevier Ltd. All rights reserved.


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.


Hezaveh H.,University of Technology Malaysia | Fazlali A.,Arak University | Noshadi I.,University of Technology Malaysia
Journal of the Taiwan Institute of Chemical Engineers | Year: 2012

In this article, synthesis and rheological behavior of Fe 2O 3 magnetic nanoparticles ferrofluids in paraffin base as well as their magnetoviscos effects have been investigated. In order to prepare the ferrofluids, ball mill and ultrasonic bath were used. Then rheological behavior of the system was studied using a standard rotating rheometer. Oleic acid was used to stabilize ferrofluids. Also the effect of magnetic field on the fluid was studied. It is shown that using magnetic field will cause noticeable increase in viscosity at constant shear rate. This increase in viscosity, however, is limited to a specific rate of magnetic field. Also, a novel correlation for predicting temperature dependency of fluid has been presented. © 2011 Taiwan Institute of Chemical 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.


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.


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.


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.


Nejat P.,University of Technology Malaysia | Jomehzadeh F.,University of Technology Malaysia | Taheri M.M.,University of Technology Malaysia | Gohari M.,Arak University
Renewable and Sustainable Energy Reviews | Year: 2015

Climate change and global warming as the main human societies' threats are fundamentally associated with energy consumption and GHG emissions. The residential sector, representing 27% and 17% of global energy consumption and CO2 emissions, respectively, has a considerable role to mitigate global climate change. Ten countries, including China, the US, India, Russia, Japan, Germany, South Korea, Canada, Iran, and the UK, account for two-thirds of global CO2 emissions. Thus, these countries' residential energy consumption and GHG emissions have direct, significant effects on the world environment. The aim of this paper is to review the status and current trends of energy consumption, CO2 emissions and energy policies in the residential sector, both globally and in those ten countries. It was found that global residential energy consumption grew by 14% from 2000 to 2011. Most of this increase has occurred in developing countries, where population, urbanization and economic growth have been the main driving factors. Among the ten studied countries, all of the developed ones have shown a promising trend of reduction in CO2 emissions, apart from the US and Japan, which showed a 4% rise. Globally, the residential energy market is dominated by traditional biomass (40% of the total) followed by electricity (21%) and natural gas (20%), but the total proportion of fossil fuels has decreased over the past decade. Energy policy plays a significant role in controlling energy consumption. Different energy policies, such as building energy codes, incentives, energy labels have been employed by countries. Those policies can be successful if they are enhanced by making them mandatory, targeting net-zero energy building, and increasing public awareness about new technologies. However, developing countries, such as China, India and Iran, still encounter with considerable growth in GHG emissions and energy consumption, which are mostly related to the absence of strong, efficient policy. © 2014 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.


Farahany S.,University of Technology Malaysia | Ourdjini A.,University of Technology Malaysia | Idrsi M.H.,University of Technology Malaysia | Shabestari S.G.,Iran University of Science and Technology
Thermochimica Acta | Year: 2013

Al-Si and Al-Cu eutectic phases strongly affect the properties of Al-Si-Cu cast alloys. The characteristic parameters of these two eutectic phases with addition of bismuth, antimony and strontium under different cooling rates (0.6-2 C/s) were investigated in ADC12 alloy using in situ thermal analysis. Results show that additives affect the Al-Si phase more than the Al-Cu (Al 2Cu) phase. Addition elements showed two different scenarios in response to cooling rate in terms of recalescence of the Al-Si eutectic phase. Both Bi and Sb caused an increase in recalescence with increased cooling rate but Sr addition reduced the recalescence. Additions of Sb and Sr increased the nucleation temperature of Al2Cu, but addition of Bi produced an opposite effect. There seems to be relationship between the solidification temperature range and fraction solid of Al-Si and Al2Cu eutectic phases. As the cooling rate increases the fraction solid of Al-Si decreased and that of Al2Cu increased. © 2013 Elsevier B.V. All rights reserved.


Garoosi F.,Semnan University | Jahanshaloo L.,University of Technology Malaysia | Garoosi S.,Islamic Azad University at Shahrood
Powder Technology | Year: 2015

A numerical study of mixed convection heat transfer of nanofluid (Al2O3-water) in a lid driven cavity flow is carried out by using a Buongiorno model. Several pairs of heater and cooler (HACs) with isothermal walls of Th and Tc (Th>Tc) are located inside the cavity. Two-dimensional Navier-Stokes, energy and volume fraction equations are solved using the finite volume method. The effects of Brownian and thermophoresis diffusion, which cause non-homogeneity, are considered. The effects of volume fraction (0≤ϕ≤0.05) and nanoparticles' diameter (25nm≤dp≤145nm) with the location, orientation and number of HACs on flow structure and heat transfer rate are examined in different Richardson numbers (0.01≤Ri≤100).The simulation results indicate that there is an optimal volume fraction of the nano-particles at each Richardson number for which the maximum heat transfer rate can be obtained. Moreover, it is found that for a constant surface area of the HAC at the entire range of Richardson number, the rate of heat transfer is increased by changing the orientation of the HAC from horizontal to vertical. Results also indicate that at low Ri, the distribution of the solid particles remains almost uniform. © 2014 Elsevier B.V.


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.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-SICA | Phase: NMP.2012.2.2-6 | Award Amount: 4.88M | Year: 2013

The project 4G-PHOTOCAT allies the expertise of 7 academic and 3 industrial partners from 5 EU countries (Germany, United Kingdom, Czech Republic, Poland, and Finland) and 2 ASEAN countries (Malaysia and Vietnam) for the development of a novel generation of low-cost nano-engineered photocatalysts for sunlight-driven water depollution. Through rational design of composites in which the solar light-absorbing semiconductors are coupled to nanostructured redox co-catalysts based on abundant elements, the recombination of photogenerated charges will be suppressed and the rate of photocatalytic reactions will be maximized. In order to achieve fabrication of optimal architectures, advanced chemical deposition techniques with a high degree of control over composition and morphology will be employed and further developed. Furthermore, novel protocols will be developed for the implementation of the photocatalysts into a liquid paint, allowing for the deposition of robust photoactive layers onto flat surfaces, without compromising the photoactivity of immobilized photocatalysts. Such paintable photoreactors are envisaged particularly as low-cost devices for detoxification of water from highly toxic persistent organic pollutants which represent a serious health issue in many remote rural areas of Vietnam and other countries. The 4G-PHOTOCAT project will provide novel scientific insights into the correlation between compositional/structural properties and photocatalytic reaction rates under sunlight irradiation, as well as improved fabrication methods and enhanced product portfolio for the industrial partners. Finally, 4G-PHOTOCAT will lead to intensified collaboration between scientists working at the cutting edge of synthetic chemistry, materials science, heterogeneous photocatalysis, theoretical modelling, and environmental analytics, as well as to unique reinforcement of cooperation between scientists and industry partners from EU and ASEAN countries.


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.


Mansourizadeh A.,Islamic Azad University at Gachsaran | Mansourizadeh A.,University of Technology Malaysia | Ismail A.F.,University of Technology Malaysia
International Journal of Greenhouse Gas Control | Year: 2011

Carbon dioxide (CO2), the main greenhouse gas, has been associated with global climate change. Therefore, it is important to develop technologies to mitigate this issue. In present study, porous hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes with developed structure for CO2 absorption were prepared via a wet spinning process. The prepared membranes were characterized in terms of morphology examination, gas permeability, critical water entry pressure (CEPw) and mass transfer resistance. From the morphology examination, the membrane showed an almost sponge-like structure with inner skinless layer and ultra-thin outer skin layer. Results of gas permeation test indicated that the membrane possess very small mean pore size (3.96nm) with high surface porosity. The CO2 absorption experiment demonstrated a significant improvement in the CO2 flux of the prepared PVDF membrane compared to the commercial porous polytetrafluoroethylene (PTFE) hollow fiber membrane. At the absorbent flow rate of 200ml/min, CO2 flux of the PVDF membrane (4.10×10-4mol/m2s) was approximately 68% higher than the CO2 flux of the PTFE membrane. In addition, the results indicated that an approximate 25% CO2 flux reduction was gradually occurred at initial 26h, then the CO2 flux maintained constant over 140h of the operation. © 2010 Elsevier Ltd.


Mansourizadeh A.,Islamic Azad University at Gachsaran | Mansourizadeh A.,University of Technology Malaysia | Ismail A.F.,University of Technology Malaysia
Desalination | Year: 2012

Wetting resistance and gas permeability are the main factors for membrane contactor applications, which can be optimized according to the membrane morphology. In present study, three different types of the membrane morphology were obtained via a dry-wet spinning technique. By measuring cloud point data and viscosity, the polymer dope composition was adjusted to produce the different morphologies. The membranes with large finger-like, small finger-like and almost sponge-like morphology were obtained. The plain PVDF membrane with large finger-likes morphology presented the higher N 2 permeance, lower wetting pressure and larger mean pore size (0.08μm). By addition of phosphoric acid into the spinning dope, the prepared sponge-like morphology resulted in the high surface porosity with small pore sizes, which demonstrated good permeability and wetting pressure. It was found that the mean pore size measured by gas permeation method was approximately three times larger than those from FESEM examination. CO 2 stripping from water was conducted through the gas-liquid membrane contactors. The membranes with smaller pore sizes and higher wetting pressure presented higher stripping performance. In conclusion, a structurally developed PVDF hollow fiber membrane for gas-liquid contactor applications can be achieved by controlling the membrane morphology. © 2011 Elsevier B.V.


Naim R.,University of Technology Malaysia | Naim R.,Universiti Malaysia Pahang | Ismail A.F.,University of Technology Malaysia | Mansourizadeh A.,Islamic Azad University at Gachsaran
Journal of Membrane Science | Year: 2012

Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a wet-spinning process. The prepared fibers were characterized in terms of contact angle, gas permeability, wetting pressure and morphology. CO 2 stripping from preloaded aqueous diethanolamine solution was conducted through the gas-liquid membrane contactors. The effects of lithium chloride (LiCl) concentration on the membrane properties and CO 2 stripping performance were investigated. The addition of different LiCl concentration resulted in a less finger-like structure, with highly effective surface porosity and high wetting pressure. Conversely, N 2 permeability, contact angle value and membrane pore size were reduced as the concentration of the additives were increased. For stripping flux performance, membrane with 5wt% LiCl demonstrated the highest flux of 1.61×10 -2mol/m 2s at 110ml/min of the liquid flow rate. It was found that the membrane with less finger-like structure and higher effective surface porosity exhibited higher stripping efficiency. These results suggest that developed membrane structure can be an alternative for the CO 2 stripping through gas-liquid membrane contactors. © 2011 Elsevier B.V.


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.


Mahmoudian S.,University of Technology Malaysia | Mahmoudian S.,Islamic Azad University at Kashan | Wahit M.U.,University of Technology Malaysia | Ismail A.F.,University of Technology Malaysia | Yussuf A.A.,Kuwait Institute for Scientific Research
Carbohydrate Polymers | Year: 2012

Regenerated cellulose/montmorillonite (RC/MMT) nanocomposite films were successfully prepared in ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl) using solution casting method. The effect of MMT loading on the thermal, mechanical, gas permeability and water absorption properties of the nanocomposite films was investigated. X-ray diffraction analysis revealed a cellulose II crystalline structure and well dispersed MMT in RC/MMT nanocomposite films. Presence of MMT enhanced the thermal and thermal-oxidative stability and char yield of RC. The tensile strength and Young's modulus of RC films improved by 12% and 40%, respectively with the addition of 6 wt.% MMT. RC/MMT nanocomposite films exhibited improved gas barrier properties and water absorption resistance compared to RC. The results demonstrated that there is a possible interface interaction between cellulose and MMT which yielded better thermal and mechanical properties of the nanocomposite films as compared to pure cellulose. © 2012 Elsevier Ltd. All rights reserved.


Olatunji S.O.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia | Abdulraheem A.,King Fahd University of Petroleum and Minerals
Computers in Industry | Year: 2011

In this work, the use of type-2 fuzzy logic systems as a novel approach for predicting permeability from well logs has been investigated and implemented. Type-2 fuzzy logic system is good in handling uncertainties, including uncertainties in measurements and data used to calibrate the parameters. In the formulation used, the value of a membership function corresponding to a particular permeability value is no longer a crisp value; rather, it is associated with a range of values that can be characterized by a function that reflects the level of uncertainty. In this way, the model will be able to adequately account for all forms of uncertainties associated with predicting permeability from well log data, where uncertainties are very high and the need for stable results are highly desirable. Comparative studies have been carried out to compare the performance of the proposed type-2 fuzzy logic system framework with those earlier used methods, using five different industrial reservoir data. Empirical results from simulation show that type-2 fuzzy logic approach outperformed others in general and particularly in the area of stability and ability to handle data in uncertain situations, which are common characteristics of well logs data. Another unique advantage of the newly proposed model is its ability to generate, in addition to the normal target forecast, prediction intervals as its by-products without extra computational cost. © 2010 Elsevier B.V. All rights reserved.


Amjad M.,University of Technology Malaysia | Amjad M.,Islamia University of Bahawalpur | Salam Z.,University of Technology Malaysia
IEEE Transactions on Industrial Electronics | Year: 2014

It is well known that ozone concentration depends on air/oxygen input flow rate and power consumed by the ozone chamber. For every chamber, there exists a unique optimum flow rate that results in maximum ozone concentration. If the flow rate is increased (beyond) or decreased (below) from this optimum value, the ozone concentration drops. This paper proposes a technique whereby the concentration can be maintained even if the flow rate increases. The idea is to connect n number of ozone chambers in parallel, with each chamber designed to operate at its optimum point. Aside from delivering high ozone concentration at high flow rate, the proposed system requires only one power supply to drive all these (multiple) chambers simultaneously. In addition, due to its modularity, the system is very flexible, i.e., the number of chambers can be added or removed as demanded by the (output) ozone requirements. This paper outlines the chamber design using mica as dielectric and the determination of its parameters. To verify the concept, three chambers are connected in parallel and driven by a single transformer-less LCL resonant power supply. Moreover, a closed-loop feedback controller is implemented to ensure that the voltage gain remains at the designated value even if the number of chambers is changed or there is a variation in the components. It is shown that the flow rate can be increased linearly with the number of chambers while maintaining a constant ozone concentration. © 1982-2012 IEEE.


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.


Olatunji S.O.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia | Abdulraheem A.,King Fahd University of Petroleum and Minerals
Information Fusion | Year: 2014

Extreme learning machines (ELM), as a learning tool, have gained popularity due to its unique characteristics and performance. However, the generalisation capability of ELM often depends on the nature of the dataset, particularly on whether uncertainty is present in the dataset or not. In order to reduce the effects of uncertainties in ELM prediction and improve its generalisation ability, this paper proposes a hybrid system through a combination of type-2 fuzzy logic systems (type-2 FLS) and ELM; thereafter the hybrid system was applied to model permeability of carbonate reservoir. Type-2 FLS has been chosen to be a precursor to ELM in order to better handle uncertainties existing in datasets beyond the capability of type-1 fuzzy logic systems. The type-2 FLS is used to first handle uncertainties in reservoir data so that its final output is then passed to the ELM for training and then final prediction is done using the unseen testing dataset. Comparative studies have been carried out to compare the performance of the proposed T2-ELM hybrid system with each of the constituent type-2 FLS and ELM, and also artificial neural network (ANN) and support Vector machines (SVM) using five different industrial reservoir data. Empirical results show that the proposed T2-ELM hybrid system outperformed each of type-2 FLS and ELM, as the two constituent models, in all cases, with the improvement made to the ELM performance far higher against that of type-2 FLS that had a closer performance to the hybrid since it is already noted for being able to model uncertainties. The proposed hybrid also outperformed ANN and SVM models considered. © 2012 Elsevier B.V. All rights reserved.


Salam Z.,University of Technology Malaysia | Amjad M.,University of Technology Malaysia | Amjad M.,Islamia University of Bahawalpur | Facta M.,University of Technology Malaysia | Mekhilef S.,University of Malaya
IEEE Transactions on Power Electronics | Year: 2013

This paper describes the analysis and design of an LCL resonant power supply for ozone generation. The main advantage of the proposed topology is the absence of high-voltage transformer; the high voltage gain is achievable by means of double-resonance phenomena. Furthermore, the bandwidth is wider than the ordinary LC and its phase difference is constant over specific frequency range; as a result, an open-loop operation can be implemented. The complete analysis and design procedure of the power supply is presented. The design procedure is verified by implementing the power supply to drive a dielectric barrier discharge prototype ozone chamber. The hardware results are found to be in close agreement with simulation and thus justify the validity of the design procedures. The proposed circuit is suitable for portable ozone power supply fed by low-voltage source such as battery or photovoltaic module. © 1986-2012 IEEE.


Olatunji S.O.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia | Raheem A.A.A.,King Fahd University of Petroleum and Minerals
Expert Systems with Applications | Year: 2011

This paper presented a new prediction model of pressure-volume-temperature (PVT) properties of crude oil systems using type-2 fuzzy logic systems. PVT properties are very important in the reservoir engineering computations, and its accurate determination is important in the primary and subsequent development of an oil field. Earlier developed models are confronted with several limitations especially in uncertain situations coupled with their characteristics instability during predictions. In this work, a type-2 fuzzy logic based model is presented to improve PVT predictions. In the formulation used, the value of a membership function corresponding to a particular PVT properties value is no longer a crisp value; rather, it is associated with a range of values that can be characterized by a function that reflects the level of uncertainty. In this way, the model will be able to adequately model PVT properties. Comparative studies have been carried out and empirical results show that Type-2 FLS approach outperforms others in general and particularly in the area of stability, consistency and the ability to adequately handle uncertainties. Another unique advantage of the newly proposed model is its ability to generate, in addition to the normal target forecast, prediction intervals without extra computational cost. © 2011 Elsevier Ltd. All rights reserved.


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.


Saeidi S.,University of Technology Malaysia | Amin N.A.S.,University of Technology Malaysia | Rahimpour M.R.,Shiraz University
Journal of CO2 Utilization | Year: 2014

Fossil fuel depletion, global warming, climate change, and steep hikes in the price of fuels are driving scientists to investigate on commercial and environmentally friendly fuels. The process of CO2 conversion to value-added products has been considered as a possible remedy to fulfill the requirements. The present review paper comprehensively discusses two different processes, namely hydrocarbon and methanol synthesis which are extensively used to convert CO2 to value-added products. Reaction mechanisms as well as the effects of catalyst, reactor type and operating conditions on product efficiency enhancement of each process are reviewed. Furthermore a brief overview on the reactor types as the most effective component of the theoretical and experimental reported results on the process improvement is given. All the information is tabulated in order to make the gathered information easily conclusive. Finally, by taking the available information into account the best reactor configuration which is adjustable to reaction mechanism is proposed. © 2014 Elsevier B.V.


Olatunji S.O.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia | Abdul Raheem A.A.,King Fahd University of Petroleum and Minerals
Applied Soft Computing Journal | Year: 2014

This paper proposed an improved sensitivity based linear learning method (SBLLM) model through the hybridization of type-2 fuzzy logic systems (type-2 FLS) and SBLLM. The generalization abilities of the SBLLM often rely on whether the available dataset is free of uncertainties to ensure successful result, which means that its generalization capability is sometimes limited depending on the nature of the dataset. Type-2 FLS has been choosing in order to better handle uncertainties existing in datasets and in the membership functions (MFs) in the traditional type-1 fuzzy logic system (FLS). In the proposed method, the type-2 FLS is used to handle uncertainties in reservoir data so that the cleaned data from type-2 FLS is then passed to the SBLLM for training and then final prediction using testing dataset follows. Comparative studies have been carried out to compare the performance of the proposed hybrid system with that of the standard SBLLM. Empirical results from simulation show that the proposed improved hybrid model has greatly improved upon the performance of the standard SBLLM. © 2013 Elsevier B.V.


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.


Zahedi G.,University of Technology Malaysia | Elkamel A.,University of Waterloo | Lohi A.,Ryerson University
Journal of Food Engineering | Year: 2010

The subject of this study is to optimize supercritical extraction of nimbin from neem seeds using a Genetic Algorithm (GA) technique. In order to investigate the effect of parameters on nimbin extraction yield, a partial differential equation model based on mass conservation was developed and solved numerically. The results were successfully validated and a parameter estimation problem that employs laboratory experimental data was solved. Using this validated model and the optimized set of parameters in the model, another problem was formulated with the aim of optimizing the extraction process. Profit was set as the objective function. Using a GA optimization algorithm, it was found that profit achieves its maximum when T = 305 k, P = 200 bar, carbon dioxide flow rate = 0.967 cm3/min and dp = 0.1431 cm. The ability of the GA algorithm in optimizing the process was compared with a traditional Gradient Search (GS) optimization technique. THE GA technique proved to be a more efficient technique; especially when considering computational effort in reaching an optimal solution. © 2009 Elsevier Ltd. All rights reserved.


Ng S.M.,University of Technology Malaysia | Narayanaswamy R.,University of Manchester
Journal of Inclusion Phenomena and Macrocyclic Chemistry | Year: 2012

The interaction between b-cyclodextrin (bCD) and N-phenyl-1-naphthylamine has been studied spectrofluorimetrically and found to form a 1:1 (βCD:NPN) inclusion complex at optimum conditions of pH 8 with the formation time of 120 s. The association constant of the complex was established to be 6.0 × 10 2 M, while a remarkable enhancement in fluorescence intensity was also observed at 445 nm with excitation of 334 nm. A spectroflurometric method for the detection of N-phenyl-1- naphthylamine has been developed having a dynamic range linear up to 4.67 × 10 -7 M with a limit of detection of 0.58 nM. The repeatability study at two different Bcd concentrations of 1.0 × 10 -4 and 4.0 × 10 -4 M was found to give RSD values of 2.40 and 1.42%, respectively. Artificial neural network (ANN) has been utilised to model the analytical system and successfully extended the analytical dynamic range up to 8.0 × 10 -7 M from the original 4.67 × 10 -7 M, brief network training and the optimum parameters of are described in this work. © 2011 Springer Science+Business Media B.V.


Ng S.M.,University of Technology Malaysia | Narayanaswamy R.,University of Manchester
Analytica Chimica Acta | Year: 2011

Despite the increasing number of usage of molecularly imprinted polymers (MIPs) in optical sensor application, the correlation between the analytical signals and the binding isotherms has yet to be fully understood. This work investigates the relationship between the signals generated from MIPs sensors to its respective binding affinity variables generated using binding isotherm models. Two different systems based on the imprinting of metal ion and organic compound have been selected for the study, which employed reflectance and fluorescence sensing schemes, respectively. Batch binding analysis using the standard binding isotherm models was employed to evaluate the affinity of the binding sites. Evaluation using the discrete bi-Langmuir isotherm model found both the MIPs studied have generally two classes of binding sites that was of low and high affinities, while the continuous Freundlich isotherm model has successfully generated a distribution of affinities within the investigated analytical window. When the MIPs were incorporated as sensing receptors, the changes in the analytical signal due to different analyte concentrations were found to have direct correlation with the binding isotherm variables. Further data analyses based on this observation have generated robust models representing the analytical performance of the optical sensors. The best constructed model describing the sensing trend for each of the sensor has been tested and demonstrated to give accurate prediction of concentration for a series of spiked analytes. © 2011 Elsevier B.V.


Ahmed H.E.,University of Anbar | Mohammed H.A.,University of Technology Malaysia | Yusoff M.Z.,University of Tenaga Nasional
Renewable and Sustainable Energy Reviews | Year: 2012

The subject of heat transfer enhancement has significant interest to develop the compact heat exchangers in order to obtain a high efficiency, low cost, light weight, and size as small as possible. Therefore, energy cost and environmental considerations are going on to encourage attempts to invent better performance over the existence designs. Streamwise vortices can be generated using small flow manipulators or protrusions such as wings and winglets configurations. Single-pair, single row, or two dimensional array of vortex generators (VGs) can be punched, mounted, attached or embedded in the boundary layer of flow channel. VGs generate longitudinal and transverse vortices, while longitudinal vortices are more efficient for heat transfer enhancement than transverse vortices. A dramatic augmentation in thermal performance of the thermal system can be achieved but pressure drop penalty is existed. Several parameters have been overviewed in this paper, which have pronounced effect on the convective heat transfer coefficient and pressure drop penalty. These parameters are: attack angle of VG, geometry of VG, standard and novel types of VG, spacing between the VG tips, number of pairs of VGs in the flow direction, rectangular or circular array arrangement of VGs, common-flow upper (CFU) or common-flow down (CFD) configuration of VG, pointing up (PU) or pointing down (PD) arrangement of VG with flow direction, Re number, channel aspect ratio, number of tubes of fin-tube heat exchanges (HE), circular or oval tubes of fin-tube HE, and location of VG respect to the tube of HE or from leading edge of the channel. This paper gives an overview about the early studies done in order to improve the performance of thermal systems with minimal pressure losses to derive systems with less negative impact on the environment and high level of energy economic. This study also provides an outlook for future work using nanofluids with vortex generators. This article is also summarizes the recent experimental and numerical developments on the thermal conductivity measurements of nanofluids, thermal conductivity enhancement, convection and conduction heat transfer, some applications, main problems and suggestions for future works. © 2012 Elsevier Ltd.


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.


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..


Idris I.,University of Technology Malaysia | Selamat A.,University of Technology Malaysia | Omatu S.,Information and Communication Engineering
Engineering Applications of Artificial Intelligence | Year: 2014

Email spam is an increasing problem that not only affects normal users of internet but also causes a major problem for companies and organizations. Earlier techniques have been impaired by the adaptive nature of unsolicited email spam. Inspired by adaptive algorithm, this paper introduces a modified machine learning technique of the human immune system called negative selection algorithm (NSA). A local selection differential evolution (DE) generates detectors at the random detector generation phase of NSA; code named NSA-DE. Local outlier factor (LOF) is implemented as fitness function to maximize the distance of generated spam detectors from the non-spam space. The problem of overlapping detectors is also solved by calculating the minimum and maximum distance of two overlapped detectors in the spam space. From the experiments, the results show that the detection accuracy of NSA-DE is 83.06% while the standard negative selection algorithm is 68.86% at 7000 generated detectors. © 2013 Elsevier Ltd. All rights reserved.


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.


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.


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.


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.


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.


Juang L.-H.,University of Technology Malaysia | Wu M.-N.,National Taichung Institute of Technology
Measurement: Journal of the International Measurement Confederation | Year: 2011

We present a preliminary design and experimental results of psoriasis objects tracking method for color-skin images that utilizes k-means clustering with morphological processing technique. The method is capable of solving unable exactly contoured psoriasis objects problem in color-skin image by adding the morphological reconstruction operation. The key idea of the proposed image processing procedure is the k-means clustering method helps the rough segmentation, then the dilation and erosion method are adapted to refine previous results. In this paper we investigate the possibility of employing this approach for psoriasis image application. The application of the proposed method for tracking psoriasis is demonstrated to help pathologists distinguish exactly its size and region. In this paper, we propose a psoriasis image segmentation procedure to improve the accuracy. The experimental results demonstrate that the misclassification error is very small between the proposed result and hand drawing. © 2011 Elsevier Ltd. All rights reserved.


Razzaque M.A.,University of Technology Malaysia | Bleakley C.,University College Dublin | Dobson S.,University of St. Andrews
ACM Transactions on Sensor Networks | Year: 2013

Wireless sensor networks (WSNs) are highly resource constrained in terms of power supply, memory capacity, communication bandwidth, and processor performance. Compression of sampling, sensor data, and communications can significantly improve the efficiency of utilization of three of these resources, namely, power supply, memory and bandwidth. Recently, there have been a large number of proposals describing compression algorithms for WSNs. These proposals are diverse and involve different compression approaches. It is high time that these individual efforts are put into perspective and a more holistic view taken. In this article, we take a step in that direction by presenting a survey of the literature in the area of compression and compression frameworks in WSNs. A comparative study of the various approaches is also provided. In addition, open research issues, challenges and future research directions are highlighted. © 2013 ACM.


Hosseini S.E.,University of Technology Malaysia | Wahid M.A.,State University of New York at Buffalo | Abuelnuor A.A.A.,University of Technology Malaysia
International Review of Mechanical Engineering | Year: 2012

In recent decade, more stringent laws have been ordained to cope with environmental issues and global warming. Industrial sectors have been urged to substitute new combustion methods to decline their emissions, but the cost of pollutant reduction in traditional combustion is efficiency abatement. In the other word, emission and fuel consumption cannot be declined simultaneously by conventional combustion. High temperature air combustion (Hitac) is an innovative substitution for conventional combustion which has been developed to increase combustion efficiency and to decline pollutant formation contemporaneously. Recently, some valuable experimental and numerical analysis have been done to study the variety aspects of Hitac and to study the reasons of the compatibility of high efficiency and low NO x production in Hitac area. The outstanding characteristic of Hitac is its sustainability under low oxygen concentration when the combustion air is preheated more than the fuel auto-ignition temperature. Therefore, it can be observed that thermal NO x is suppressed due to lack of oxygen concentration. This paper is concerned with NO x formation reduction in Hitac systems via physical and chemical analysis. Chemical kinetic, heat transfer concepts, simulation studies and experimental investigations have been employed to analyze NO x formation mitigation in Hitac method. © 2012 Praise Worthy Prize S.r.l. - All right reserved.


Khoo M.B.C.,Universiti Sains Malaysia | Teoh W.L.,Universiti Sains Malaysia | Castagliola P.,University of Nantes | Lee M.H.,University of Technology Malaysia
International Journal of Production Economics | Year: 2013

The double sampling (DS) X̄ chart detects small and moderate mean shifts quickly. Furthermore, this chart can reduce the sample size. The DS X̄ chart is usually investigated assuming that the process parameters are known. Nevertheless, the process parameters are usually unknown and are estimated from an in-control Phase-I dataset. This paper (i) evaluates the performances of the DS X̄ chart when process parameters are estimated by means of a new proposed theoretical method, (ii) shows that performances with estimated parameters are different from that with known parameters, and (iii) proposes three optimal design procedures: the first design minimizes the out-of-control average run length, the second design minimizes the in-control average sample size and the third design minimizes the average extra quadratic loss, by considering the number of Phase-I samples in these three designs. Additionally, for ease of implementation, this paper provides the new optimal parameters specially computed for the DS X̄ chart with estimated parameters, based on the number of Phase-I samples used in practice. These findings will lead to a more economically feasible process monitoring situation, especially when the process parameters are unknown. © 2013 Elsevier B.V. All rights reserved.


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.


Thangavelu S.K.,University of Technology Malaysia | Ahmed A.S.,University Malaysia Sarawak | Ani F.N.,University of Technology Malaysia
Applied Energy | Year: 2014

Bioethanol production from sago pith waste (SPW) using microwave hydrothermal hydrolysis accelerated by carbon dioxide was studied. The structural change in the SPW after hydrolysis, ethanol purity after fermentation, and distillation were investigated. Energy consumption for microwave hydrothermal hydrolysis was evaluated. A maximum of 43.8% theoretical glucose and 40.5% theoretical ethanol yield were obtained. The ethanol yield coefficient obtained in fermentation was 0.47 (g. ethanol per g. glucose) which was 15.6. g. ethanol per 100. g dry SPW. It was also discovered that the lowest energy consumption occurred when energy input was fixed at 108. kJ (900. W for 2. min), amounting to 33. kJ and 69. kJ to produce one gram glucose after hydrothermal hydrolysis and one gram ethanol after fermentation, respectively. The developed technique for SPW resulted in higher energy saving compared to previous techniques in the absence of enzymes, acid or base catalyst. © 2014 Elsevier Ltd.


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.


Eltyeb S.,University of Technology Malaysia | Eltyeb S.,Sudan University of Science and Technology | Salim N.,University of Technology Malaysia
Journal of Cheminformatics | Year: 2014

The rapid increase in the flow rate of published digital information in all disciplines has resulted in a pressing need for techniques that can simplify the use of this information. The chemistry literature is very rich with information about chemical entities. Extracting molecules and their related properties and activities from the scientific literature to "text mine" these extracted data and determine contextual relationships helps research scientists, particularly those in drug development. One of the most important challenges in chemical text mining is the recognition of chemical entities mentioned in the texts. In this review, the authors briefly introduce the fundamental concepts of chemical literature mining, the textual contents of chemical documents, and the methods of naming chemicals in documents. We sketch out dictionary-based, rule-based and machine learning, as well as hybrid chemical named entity recognition approaches with their applied solutions. We end with an outlook on the pros and cons of these approaches and the types of chemical entities extracted. © 2014 Eltyeb and Salim; licensee Chemistry Central Ltd.


Yusup N.,University of Technology Malaysia | Yusup N.,University Malaysia Sarawak | Zain A.M.,University of Technology Malaysia | Hashim S.Z.M.,University of Technology Malaysia
Expert Systems with Applications | Year: 2012

In highly competitive manufacturing industries nowadays, the manufactures ultimate goals are to produce high quality product with less cost and time constraints. To achieve these goals, one of the considerations is by optimizing the machining process parameters such as the cutting speed, depth of cut, radial rake angle. Recently, alternative to conventional techniques, evolutionary optimization techniques are the new trend for optimization of the machining process parameters. This paper gives an overview and the comparison of the latest five year researches from 2007 to 2011 that used evolutionary optimization techniques to optimize machining process parameter of both traditional and modern machining. Five techniques are considered, namely genetic algorithm (GA), simulated annealing (SA), particle swarm optimization (PSO), ant colony optimization (ACO) and artificial bee colony (ABC) algorithm. Literature found that GA was widely applied by researchers to optimize the machining process parameters. Multi-pass turning was the largest machining operation that deals with GA optimization. In terms of machining performance, surface roughness was mostly studied with GA, SA, PSO, ACO and ABC evolutionary techniques. © 2012 Elsevier Ltd. All rights reserved.


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.


Ghazai A.J.,University of Technology Malaysia | Thahab S.M.,University of Kufa | Hassan H.A.,University of Technology Malaysia | Hassan Z.,University of Technology Malaysia
Optics Express | Year: 2011

The effect of polarization-matched Al0.25In 0.08Ga0.67N electron-blocking layer (EBL) on the optical performance of ultraviolet Al0.08In0.08Ga0.84N/ Al0.1In 0.01Ga0.84N multi-quantum well (MQW) laser diodes (LDs) was investigated. The polarization-matched Al0.25In 0.08Ga0.67N electron blocking layer (EBL) was employed in an attempt to reduce the polarization effect inside the active region of the diodes. The device performance which is affected by piezoelectric was studied via drift-diffusion model for carrier transport, optical gain and losses using the simulation program of Integrated System Engineering Technical Computer Aided design (ISE TCAD). The optical performance of the LD using quaternary Al 0.25In0.08Ga0.67N EBL was compared with the LD using ternary Al0.3Ga0.7N EBL where both materials have the same energy band gap of Eg = 3.53 eV. The self-consistent ISE-TCAD simulation program results showed that the polarization-matched quaternary Al0.25In0.08Ga0.67N EBL is beneficial as it confines the electrons inside the quantum well region better than ternary Al0.3Ga0.7N EBL. The results indicated that the use of Al0.25In0.08Ga0.67N EBL has lower threshold current and higher optical intensity than those for Al 0.3Ga0.7N EBL. The effect of Al0.25In 0.08Ga0.67N EBL thickness on the performance of LDs has also been studied. Results at room temperature indicated that lower threshold current, high slope efficiency, high output power, and high differential quantum efficiency DQE occurred when the thickness of Al0.25In 0.08Ga0.67N EBL was 0.25 μm. © 2011 Optical Society of America.


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.


Ashnani M.H.M.,University of Technology Malaysia | Ashnani M.H.M.,University of Tehran | Johari A.,University of Technology Malaysia | Hashim H.,University of Technology Malaysia | Hasani E.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2014

Recent surge in crude oil price, finite fossil oil resources, and environmental issues all have aroused grave concerns. The world in 2012 consumed up to 12,476.6 million tons oil equivalent and 87% of this energy came from fossil sources. Malaysia has encountered an increase in energy demand following the country's development and economic growth. Currently, biodiesel is one of the main options to replace petroleum-derived diesel. Thanks to its environment friendly properties and almost similar performance with fossil fuels, biodiesel sounds like a promising option. The present paper deals with available renewable energy scenarios and examines alternative energies such as biomass, solar, wind and mini-hydro energy. The purpose of using the new sources of energy is to make sure of availability of reliable and secure supply of energy for the country. The energy demand and supply are also discussed based on source and relation to the country's fuel diversification policy. The study evaluates Malaysia's status quo in energy and biodiesel market, its strengths from economic, social, and environmental viewpoints and the production of biodiesel in the country. Moreover, the country's potentials to become a leading producer of biodiesel are further studied. The concentration in the study is on biodiesel production in Malaysia. The main portion of raw material for producing biodiesel is palm oil as the country is among the largest producers of palm oil at international level. There are optimistic expectations that by developing biodiesel production in the Malaysia, not only will the countries' energy needs be met, but the country will emerge as a role model that paves the path toward more production of biodiesel all around the world. © 2014 Elsevier Ltd.


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.


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.


Sultana N.,University of Hong Kong | Sultana N.,University of Technology Malaysia | Wang M.,University of Hong Kong
Biofabrication | Year: 2012

Tissue engineering combines living cells with biodegradable materials and/or bioactive components. Composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramic with suitable properties are promising for bone tissue regeneration. In this paper, based on blending two biodegradable and biocompatible polymers, namely poly(hydroxybutyrate-co- hydroxyvalerate) (PHBV) and poly(l-lactic acid) (PLLA) with incorporated nano hydroxyapatite (HA), three-dimensional composite scaffolds with controlled microstructures and an interconnected porous structure, together with high porosity, were fabricated using an emulsion freezing/freeze-drying technique. The influence of various parameters involved in the emulsion freezing/freeze-drying technique was studied for the fabrication of good-quality polymer scaffolds based on PHBV polymers. The morphology, mechanical properties and crystallinity of PHBV/PLLA and HA in PHBV/PLLA composite scaffolds and PHBV polymer scaffolds were studied. The scaffolds were coated with collagen in order to improve wettability. During in vitro biological evaluation study, it was observed that SaOS-2 cells had high attachment on collagen-coated scaffolds. Significant improvement in cell proliferation and alkaline phosphatase activity for HA-incorporated composite scaffolds was observed due to the incorporation of HA. After 3 and 7 days of culture on all scaffolds, SaOS-2 cells also had normal morphology and growth. These results indicated that PHBV/PLLA-based scaffolds fabricated via an emulsion freezing/freeze-drying technique were favorable sites for osteoblastic cells and are promising for the applications of bone tissue engineering. © 2012 IOP Publishing Ltd.


Uddin M.J.,Bangladesh American International University | Beg O.A.,Gort Engovation Research Propulsion Biomechanics | Amin N.,University of Technology Malaysia
Journal of Magnetism and Magnetic Materials | Year: 2014

Steady two-dimensional magnetohydrodynamic laminar free convective boundary layer slip flow of an electrically conducting Newtonian nanofluid from a translating stretching/shrinking sheet in a quiescent fluid is studied. A convective heating boundary condition is incorporated. The transport equations along with the boundary conditions are first converted into dimensionless form and following the implementation of a linear group of transformations, the similarity governing equations are developed. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth fifth order method from Maple. Validation of the Maple solutions is achieved with previous non-magnetic published results. The effects of the emerging thermophysical parameters; namely, stretching/shrinking, velocity slip, magnetic field, convective heat transfer and buoyancy ratio parameters, on the dimensionless velocity, temperature and concentration (nanoparticle fraction) are depicted graphically and interpreted at length. It is found that velocity increases whilst temperature and concentration reduce with the velocity slip. Magnetic field causes to reduce velocity and enhances temperature and concentration. Velocity, temperature as well as concentration rises with convective heating parameter. The study is relevant to the synthesis of bio-magnetic nanofluids of potential interest in wound treatments, skin repair and smart coatings for biological devices. © 2014 Elsevier B.V.


Fulazzaky M.A.,University of Technology Malaysia | Fulazzaky M.A.,University of Pau and Pays de l'Adour
Analytical Methods | Year: 2012

The presence of micropollutants, particularly herbicides, in drinking water is undesired and therefore removal is required. Granular activated carbon (GAC) is used extensively to remove organic micropollutants during the treatment of potable waters. The performance of an adsorption-based separation depends on the existence of a force field at the surface of a solid. To date, the resistance of mass transfer for the adsorption of micropollutants from aqueous solution onto GAC still needs to be verified. This paper uses the developed mathematical models to analyse the global and sequential mass transfers for the adsorption of atrazine and simazine onto different GACs from a hydrodynamic column. The resistance of mass transfer is dependent on the porous diffusion before a 5% outflow occurred and both on the porous diffusion and film mass transfer after passing that percentage of outflow. The properties of adsorbate and adsorbent affecting the global, external and internal mass transfer are analysed to contribute to the investigation of adsorption mechanisms. The mechanisms of adsorption of atrazine and simazine onto GACs from the hydrodynamic column are verified. © 2012 The Royal Society of Chemistry.


Tan X.W.,University of Technology Malaysia | Romainor A.N.B.,University Malaysia Sarawak | Chin S.F.,University Malaysia Sarawak | Ng S.M.,University of Technology Malaysia
Journal of Analytical and Applied Pyrolysis | Year: 2014

This work reports the synthesis of carbon dots (C-dots) from sago industrial waste using thermal pyrolysis approach. The pyrolysis condition was found to govern the carbonisation conversion of bulk sago waste into carbon rich residue that can be further isolated to obtain carbon dots. In order to obtain the best yield of the carbon dots, optimization of the thermal pyrolysis conditions have been performed which consisted of varying temperature of carbonisation at a constant heating duration. The C-dots can be dispersed in aqueous media and portrayed a significant fluorescent property that can be observed by naked eye under a UV light source. The optimum temperature of carbonisation was determined at 400 C in which the strongest fluorescence emission was record at 390 nm with the optimum excitation wavelength of 315 nm. The fluorescence of the C-dots was found to be significantly quenched in the presence of various metal ions. Thus, the C-dots can be adopted as a potential optical probe for sensing of metal ions in aqueous media. An analytical characterization has been performed in this study over a series of commonly available metal ions and the sensing characteristics were evaluated using the standard Stern-Volmer quenching model. This study has successfully demonstrated an innovative approach of converting agricultural waste into high value optical sensing receptors for metal ions detection. © 2013 Elsevier B.V. All rights reserved.


Syahrullail S.,University of Technology Malaysia | Kamitani S.,Kagoshima University | Nakanishi K.,Kagoshima University
Tribology Transactions | Year: 2012

The performance of palm oil as a lubricant in a cold metal forming process was tested and evaluated by carrying out plane strain extrusion experiments and experimental analyses using a visioplasticity method. In the present research, two types of refined palm oil, refined, bleached, and deodorized (RBD) palm olein and RBD palm stearin, were tested as lubricants. The workpiece material was aluminum JIS-A1050. The experiments were carried out at room temperature (22°C). Paraffinic mineral oils with varying degrees of viscosity were tested for comparison. The experiment used an extrusion apparatus in which the taper dies were facing together, with zero frictional constraint at the contact plane (corresponding to the plane plate tool) conducted, and results were compared with those extruded with lubricants. Extrusion load and surface roughness of the billets were measured and compared. The distribution of the material flow velocity and effective strain in the exit zone of the billets were calculated using the visioplasticity method, and these data were also compared. The results confirmed that RBD palm olein and palm stearin provide sufficient lubrication performance in the cold work metal forming process. © 2012 Copyright Taylor and Francis Group, LLC.


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.


Hainin M.R.,University of Technology Malaysia | Yusoff N.I.Md.,National University of Malaysia | Mohd Satar M.K.I.,University of Technology Malaysia | Brown E.R.,Auburn University
Construction and Building Materials | Year: 2013

This study investigates the effect of lift thickness on (i) permeability and (ii) the time available for compaction (TAC) of hot-mix asphalt (HMA) mixes under tropical climate condition. A total of 14 HMA mixes consisting of various types, gradations, and nominal maximum aggregate sizes (NMAS) were selected. The heights for thickness (t) to NMAS ratios of 2.0, 3.0, and 4.0 were determined with appropriate mass to produce 7.0 ± 1.0% air voids. The bulk specific gravity of the samples was determined using the vacuum sealing method. The laboratory permeability test and the relationships between permeability and lift thickness were evaluated. To achieve the second objective, seven field test sections with different HMA mixes were constructed; each was about 40 m long and 3.5 m wide. Each test section was paved with thickness (t) to a nominal maximum aggregate size (NMAS) ratio of 2.0 at the beginning of the section and gradually increased to a t/NMAS ratio of 5.0 at the end of the section with air temperatures during construction ranging from 26 to 35 C. It was found that HMA mixes with a lift thickness of 30 mm and less with coarse gradation have a greater chance of having a permeability problem, even though they are compacted at the right density. In addition, the thinner the mix layer, the faster the mix cools, thus reducing the TAC. The results also suggest that the TAC for a 25 mm lift is 13 min, 23 min for 32 mm, 32 min for 38 mm, and is expected to be more than 50 min for 44 mm and above. © 2013 Elsevier Ltd. All rights reserved.


Rahmat M.F.,University of Technology Malaysia | Kamaruddin N.S.,UniKL Malaysian Spanish Institute
Sensor Review | Year: 2012

Purpose - The use of pneumatic conveying of solid bulk over long distance has become a popular technique due to low operational cost, low maintenance requirement, layout flexibility and ease of automation. The purpose of this paper is to identifity the flow regime in a pneumatic conveyor system by electrodynamic sensor placed around the pipe using fuzzy logic tools. Design/methodology/approach - Electrical charge tomography is used to detect the existence of inherent charge on the moving particles through the pipe. Linear back projection algorithm and filtered back projection algorithm are employed to produce tomography image. Baffles of different shapes are inserted to create various flow regimes, such as full flow, three quarter flow, half flow and quarter flow. Fuzzy logic tools are used to identify different flow regimes and produce filtered back concentration profiles for each flow regime. Findings - The results show significant improvement in the pipe flow image resolution and measurement. Originality/value - This paper presents a flow identifier method using electrical charge tomography and fuzzy logic to monitor solid particles flow in pipeline. © 2012 Emerald Group Publishing Limited.


Ismail Z.,University of Technology Malaysia | Hassan R.,National University of Malaysia
Proceedings - CIMSim 2011: 3rd International Conference on Computational Intelligence, Modelling and Simulation | Year: 2011

Networks are being used in various areas and the demand of users nowadays has motivated the emergence of the Mobile Ad Hoc Network (MANET). MANET is a dynamic network without fixed infrastructure due to their wireless nature and can be deployed as multi-hop packet networks. It is a wireless network and has dynamic topology due to its node mobility. There are two types of MANET, homogeneous and heterogeneous MANET. An architecture has been designed in previous work to model these two types of MANET. Three scenarios have been defined from this architecture: scenario I (communication entirely within MANET, homogeneous MANET), scenario II (communication between MANET and wireless LAN, heterogeneous MANET) and scenario III (communication between MANET with wireless LAN and wired LAN, heterogeneous MANET). MANET has its own routing protocols which can compromised with frequent route exchange, dynamic topology, bandwidth constraint and multi-hop routing. Ad hoc On Demand Distance Vector (AODV) is one of the routing protocols in MANET. The aim of this research is to assess the effects of different packet size with the implementation of AODV routing protocols in homogeneous and heterogeneous MANET through the simulation method. The three scenarios above have been developed in the OMNeT++ network simulator. The results achieved from the test have been evaluated using the metrics assigned, throughput and packet delivery ratio (PDR). The tests show that the increase of throughput and PDR performance was parallel with the increase of packet size. From the test also, we can conclude that the performance due to the packet size effect in homogeneous MANET is better than in heterogeneous MANET. © 2011 IEEE.


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.


Chow M.F.,University of Technology Malaysia | Yusop Z.,University of Technology Malaysia | Toriman M.E.,National University of Malaysia
International Journal of Environmental Science and Technology | Year: 2012

Due to differences in rainfall regimes and management practices, tropical urban catchments are expected to behave differently from temperate catchments in terms of pollutant sources and their transport mechanism. Storm Water Management Model (SWMM) was applied to simulate runoff quantity (peakflow and runoff depth) and quality (total suspended solids and total phosphorous) in residential, commercial and industrial catchments. For each catchment, the model was calibrated using 8-10 storm events and validated using seven new events. The model performance was evaluated based on the relative error, normalized objective function, Nash-Sutcliffe coefficient and 1:1 plots between the simulated and observed values. The calibration and validation results showed good agreement between simulated and measured data. Application of Storm Water Management Model for predicting runoff quantity has been improved by taking into account catchment's antecedent moisture condition. The impervious depression storages obtained for dry and wet conditions were 0. 8 and 0. 2 mm, respectively. The locally derived build-up and wash-off parameters were used for modelling runoff quality. © 2012 CEERS, IAU.


Ismail Z.,University of Technology Malaysia | Hassan R.,National University of Malaysia
17th Asia-Pacific Conference on Communications, APCC 2011 | Year: 2011

Mobile Ad Hoc Network (MANET) is a dynamic network without fixed infrastructure due to their wireless nature and can be deployed as multi-hop packet networks. It is a wireless network and has dynamic topology due to its node mobility. Networks are being used in various areas and the demand of users nowadays has motivated the emergence of the heterogeneous MANET. Compared to homogeneous MANET, heterogeneous MANET is more open to other types of network for example wireless LAN, cellular network and fixed network. In MANET, the concern is more to configuration and one of the important elements in configuration is routing. Ad hoc On Demand Distance Vector (AODV) is one of the routing protocols in MANET which can compromise with MANET characteristics. The aim of this research is to assess the performance of AODV in different mobility speed for homogeneous MANET and heterogeneous MANET through the simulation method. The simulation scenarios derived from the HetMAN architecture (as been discussed in previous work) have been developed in the OMNeT++ network simulator. The results achieved from the test have been evaluated using the metrics assigned; throughput and packet delivery ratio (PDR). The tests show that, as the speed increase, the throughput and PDR decrease for both homogeneous and heterogeneous MANET. From the test also, we can conclude that the performance in homogeneous MANET is better than in heterogeneous MANET. © 2011 IEEE.


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.


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.


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

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


Kaviri A.G.,University of Technology Malaysia | Jaafar M.N.M.,University of Technology Malaysia | Lazim T.M.,University of Technology Malaysia | Barzegaravval H.,Energy Optimization Research and Development Group EORDG
Energy Conversion and Management | Year: 2013

Combined cycle power plants (CCPPs) are preferred technology for electricity generation due to less emission and high efficiency. These cycles are made of a gas turbine, a steam turbine and Heat Recovery Steam Generator (HRSG). In the present research study, a combined cycle power plant with dual pressure and supplementary firing is selected. The optimum design procedure included designing objective function, exergy destruction per unit of inlet gas to the HRSG subject to a list of constraints. The design parameters (design variables) were drum pressure and pinch temperature difference as well as steam mass flow of HRSG high and low pressure levels. The influence of HRSG inlet gas temperature on the steam cycle efficiency is discussed. The result show increasing HRSG inlet gas temperature until 650 °C leads to increase the thermal efficiency and exergy efficiency of the cycle and after that has less improvement and start to decrease them. And also from the exergy analysis of each part of HRSG, it is cleared that the HP-EV and 2st HP-SH have the most exergy destruction respectively. In other hand, effects of HRSG inlet gas temperature on SI (sustainability index) and CO2 emission are considered. © 2012 Elsevier B.V. All rights reserved.


Sulaiman M.H.,University Malaysia Perlis | Mustafa M.W.,University of Technology Malaysia | Shareef H.,National University of Malaysia | Abd. Khalid S.N.,University of Technology Malaysia
International Journal of Electrical Power and Energy Systems | Year: 2012

This paper presents a new method for real and reactive power tracing in a deregulated power system by introducing the hybrid artificial bee colony (ABC) algorithm and least squares support vector machine (LS-SVM), namely as ABC-SVM. The idea is to use ABC algorithm to obtain the optimal values of regularization parameter, γ and Kernel RBF parameter, σ 2, which are embedded in LS-SVM toolbox and adopt a supervised learning approach to train the LS-SVM model. The technique that uses Superposition method is utilized as a teacher. Based on power flow solution and power tracing procedure by Superposition method, the description of input-output for training and testing data are created. The generators' contributions to real and reactive loads in the test system are expected can be traced accurately by proposed ABC-SVM model. In this paper, IEEE-14 bus system is used to illustrate the effectiveness of the proposed ABC-SVM model compared to that of Superposition method. The comparison with the cross-validation (CV) technique and other hybrid technique to obtain the hyper-parameters also has been presented in this paper. © 2011 Elsevier Ltd. All rights reserved.


Tajik Mansouri M.,Niroo Research Institute | Ahmadi P.,Energy Optimization Research and Development Group EORDG | Ganjeh Kaviri A.,University of Technology Malaysia | Jaafar M.N.M.,University of Technology Malaysia
Energy Conversion and Management | Year: 2012

In the present research study, the effect of HRSG pressure levels on exergy efficiency of combined cycle power plants is investigated. Hence, three types of gas turbine combined cycles, with the same gas turbine as a topping cycle are evaluated. A double pressure, and two triple pressure HRSGs (with and without reheat) are modeled. The results show how an increase in the number of pressure levels of the HRSG affect the exergy losses due to heat transfer in the HRSG and the exhaust of flue gas to the stack. Moreover, the results show that an increase in the number of pressure levels affects the exergy destruction rate in HRSG, and as a result, it causes a tangible increase in exergy efficiency of the whole cycle. The results from thermodynamic analysis show that the losses due to heat transfer in the HRSG and the exhaust of flue gas to the stack in a triple pressure reheat combined cycle are less than the other cases. From the economic analysis, it is found that increasing the number of pressure levels of steam generation leads to an increase for the total and specific investment cost of the plant for about 6% and 4% respectively. The net present value (NPV) of the plant increases for about 7% for triple pressure reheat compared to with the double pressure CCPP. Therefore, the results of economic analysis show that it is economically justifiable to increase the number of pressure levels of steam generation in HRSG. © 2012 Elsevier Ltd. All rights reserved.


Bhutta M.A.R.,University of Technology Malaysia | Tsuruta K.,Materras Oume Concrete Industry Ltd. | Mirza J.,Hydro - Quebec
Construction and Building Materials | Year: 2012

The aim of this laboratory study was to evaluate the properties of high performance porous concrete. It required no special vibration equipment and curing. The optimum mixture proportions were used in the preparation of high performance porous concretes containing three sizes of coarse aggregates with appropriate amount of high water-reducing and thickening (cohesive) agents. Tests carried out on this concrete were: slump, slump-flow, void ratio, and coefficient of permeability, compressive and flexural strengths, and strength development rate. Furthermore, a test was proposed to determine the effects of high water-reducing and thickening (cohesive) agents on self-compaction of high performance porous concrete. It was meant to evaluate its hardened properties from the viewpoint of practical application. Its strength development rate was also examined at curing age of 1, 3, 7, 14 and 28 days at 20 °C and 60% relative humidity (R. H.). Consequently, high performance porous concrete exhibited good workability and cohesiveness with no segregation or bleeding, and developed high strength compared to conventional porous concrete. The results of proposed self-compaction test for this porous concrete also showed good workability and cohesiveness without any special compaction or vibration. © 2012 Elsevier Ltd. All rights reserved.


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.


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.


Razzaque M.A.,University of Technology Malaysia | Dobson S.,University of St. Andrews
Sensors (Switzerland) | Year: 2014

Sensing of the application environment is the main purpose of a wireless sensor network. Most existing energy management strategies and compression techniques assume that the sensing operation consumes significantly less energy than radio transmission and reception. This assumption does not hold in a number of practical applications. Sensing energy consumption in these applications may be comparable to, or even greater than, that of the radio. In this work, we support this claim by a quantitative analysis of the main operational energy costs of popular sensors, radios and sensor motes. In light of the importance of sensing level energy costs, especially for power hungry sensors, we consider compressed sensing and distributed compressed sensing as potential approaches to provide energy efficient sensing in wireless sensor networks. Numerical experiments investigating the effectiveness of compressed sensing and distributed compressed sensing using real datasets show their potential for efficient utilization of sensing and overall energy costs in wireless sensor networks. It is shown that, for some applications, compressed sensing and distributed compressed sensing can provide greater energy efficiency than transform coding and model-based adaptive sensing in wireless sensor networks. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


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.


Abdullah A.,University of Technology Malaysia | Deris S.,University of Technology Malaysia | Anwar S.,Pennsylvania State University | Arjunan S.N.V.,RIKEN
PLoS ONE | Year: 2013

The development of accurate computational models of biological processes is fundamental to computational systems biology. These models are usually represented by mathematical expressions that rely heavily on the system parameters. The measurement of these parameters is often difficult. Therefore, they are commonly estimated by fitting the predicted model to the experimental data using optimization methods. The complexity and nonlinearity of the biological processes pose a significant challenge, however, to the development of accurate and fast optimization methods. We introduce a new hybrid optimization method incorporating the Firefly Algorithm and the evolutionary operation of the Differential Evolution method. The proposed method improves solutions by neighbourhood search using evolutionary procedures. Testing our method on models for the arginine catabolism and the negative feedback loop of the p53 signalling pathway, we found that it estimated the parameters with high accuracy and within a reasonable computation time compared to well-known approaches, including Particle Swarm Optimization, Nelder-Mead, and Firefly Algorithm. We have also verified the reliability of the parameters estimated by the method using an a posteriori practical identifiability test. © 2013 Abdullah et al.


Mazar Atabaki M.,University of Leeds | Mazar Atabaki M.,University of Technology Malaysia | Idris J.,University of Technology Malaysia
Materials and Design | Year: 2012

Partial transient liquid phase diffusion bonding of an aluminium metal matrix composite (Al/Mg2Si) to magnesium alloy (AZ91D) was performed using two heating rates. The influence of different heating rates on the microstructure, microhardness and shear strength has been studied. With a decrease in heating rate from 20 to 2°C/min, the Mg content in the bond line decreased and the microstructure was altered. The composition and microstructure of the joined areas were examined by X-ray diffraction (XRD) and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (EDS). It was found that a heating rate of 2°C/min resulted in an increasing in the shear strength of the joints. The kinetics of the bonding process accelerated due to the increase of solute diffusivity through grain boundaries of the metal matrix composite. Results suggest that Mg and Si contained in the interlayer favours the partial disruption of oxide films, facilitating the bonding process. © 2011 Elsevier Ltd.


Sutikno T.,Ahmad Dahlan University | Sutikno T.,University of Technology Malaysia | Idris N.R.N.,University of Technology Malaysia | Jidin A.,Hang Tuah University
Renewable and Sustainable Energy Reviews | Year: 2014

The first and the most important step in solving the environmental problems created by cars with internal combustion engines is research and development of electric vehicles. Selection of a proper drive and optimal control strategy of electric vehicles are the major factors to obtain optimal energy management in order to extend the running distance per battery charge. This paper presents a brief review of direct torque control (DTC) of induction motors (IM) as well as its implementation for electric vehicle (EV) applications. First, the basic DTC technique based on hysteresis controllers will be introduced, and then an overview of the major problems in a basic DTC scheme will be presented and explained, as well as some efforts for improving the technique. The main section presents a critical review of DTC for EV applications, taking into consideration the vehicle mechanics and aerodynamics of electric vehicles. The review is very important to provide guidelines and insights for future research and development on the DTC of IM drives for sustainable reliability and energy efficient EV applications. © 2014 Published by Elsevier Ltd. All rights reserved.


Ishaque K.,University of Technology Malaysia | Ishaque K.,Karachi Institute of Economics & Technology | Salam Z.,University of Technology Malaysia
IEEE Transactions on Industrial Electronics | Year: 2013

This paper proposes a deterministic particle swarm optimization to improve the maximum power point tracking (MPPT) capability for photovoltaic system under partial shading condition. The main idea is to remove the random number in the accelerations factor of the conventional PSO velocity equation. Additionally, the maximum change in velocity is restricted to a particular value, which is determined based on the critical study of $P$-$V$ characteristics during partial shading. Advantages of the method include: 1) consistent solution is achieved despite a small number of particles, 2) only one parameter, i.e., the inertia weight, needs to be tuned, and 3) the MPPT structure is much simpler compared to the conventional PSO. To evaluate the idea, the algorithm is implemented on a buck-boost converter and compared to the conventional hill climbing (HC) MPPT method. Simulation results indicate that the proposed method outperforms the HC method in terms of global peak tracking speed and accuracy under various partial shading conditions. Furthermore, it is tested using the measured data of a tropical cloudy day, which includes rapid movement of the passing clouds and partial shading. Despite the wide fluctuations in array power, the average efficiency for the 10-h test profile reaches 99.5%. © 1982-2012 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.


Tokit E.M.,Hang Tuah University | Mohammed H.A.,University of Technology Malaysia | Yusoff M.Z.,University of Tenaga Nasional
International Communications in Heat and Mass Transfer | Year: 2012

An interrupted microchannel heat sink (IMCHS) using nanofluids as working fluids is analyzed numerically to increase the heat transfer rate. The rectangular IMCHS is designed with length and width of 10mm and 0.057mm respectively while optimum cut section number, n c=3. The three dimensional governing equations (continuity, momentum and energy) were solved using finite volume method (FVM). Parametric study of thermal performance between pure water-cooled and nanofluid-cooled IMCHS are evaluated for particle diameter in the range of, 30nm to 60nm, volume fraction in the range of, 1% to 4%,nanofluid type of Al 2O 3, CuO, and SiO 2 at Reynolds number range of 140 to 1034 are examined. The effects of the transport properties, nanofluid type, nanoparticle volume fraction and particle diameter are investigated on the IMCHS performance. It is inferred that the Nu number for IMCHS is higher than the conventional MCHS with a slight increase of the pressure drop. It is found that highest thermal augmentation is predicted for Al 2O 3, followed by CuO, and finally for SiO 2 in terms of Nu nf/Nu pw in the IMCHS. The Nu number increased with the increase of nanoparticle volume fraction and with the decrease of nanoparticle diameter. © 2012 Elsevier Ltd.


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.


Akhtar J.,University of Punjab | Akhtar J.,University of Technology Malaysia | Saidina Amin N.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2012

Pyrolysis is one of the potential routes to harness energy and useful chemicals from biomass. The major objective of biomass pyrolysis is to produce liquid fuel, which is easier to transport, store and can be an alternative to energy source. The yield and composition of pyrolysis oil depend upon biomass feedstock and operating parameters. It is often necessary to explore about the effect of variables on response yield and instinct about their optimization. This study reviews operating variables from existing literature on biomass pyrolysis. The major operating variables include final pyrolysis temperature, inert gas sweeping, residence times, rate of biomass heating, mineral matter, size of biomass particle and moisture contents of biomass. The scope of this paper is to review the influence of operating parameters on production of pyrolysis oil. © 2012 Elsevier Ltd. All rights reserved.


Ishaque K.,Karachi Institute of Economics & Technology | Ishaque K.,University of Technology Malaysia | Salam Z.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

This paper presents a review on the state-of-the-art maximum power point tracking (MPPT) techniques for PV power system applications. The main techniques that will be deliberated are the Perturb and Observe, Incremental Conductance and Hill Climbing. The coverage will also encompass their variations and adaptive forms. In addition, the more recent MPPT approaches using soft computing methods such as Fuzzy Logic Control, Artificial Neural Network and Evolutionary Algorithms are included. Whilst the paper provides as thorough treatment of MPPT at normal (uniform) insolation, its focus will be on the applications of the abovementioned techniques during partial shading conditions. It is envisaged that this review work will be a source of valuable information for PV professionals to keep abreast with the latest progress in this area, as well as for new researchers to get started on MPPT. © 2012 Elsevier Ltd.


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.


Shamshiri M.,Hang Tuah University | Gan C.K.,Hang Tuah University | Tan C.W.,University of Technology Malaysia
2012 IEEE International Power Engineering and Optimization Conference, PEOCO 2012 - Conference Proceedings | Year: 2012

In recent decades, smart grid have become increasingly attractive to both energy producers and consumers. Amongst the main challenges for the successful realization of smart grid includes the integration of renewable energy resources, real time demand response and management of intermittent energy resources. Apart from smart grid, the development of micro-grids should take into consideration of issues such as the system performance, modeling, monitoring and controlling of the micro-grids. In particular, the recent advancements in information and communication technologies (ICTs) could facilitate the effective development of the future micro-grid system. This paper presents an overview of smart grids features and highlights the recent development of micro-grid laboratories in Europe, US and Japan. © 2012 IEEE.


Chin V.J.,University of Technology Malaysia | Salam Z.,University of Technology Malaysia | Ishaque K.,Karachi Institute of Economics & Technology
Applied Energy | Year: 2015

This review paper deliberates the important works on the modelling and parameters estimation of photovoltaic (PV) cells for PV simulation. It provides the concepts, features, and highlights the advantages and drawbacks of three main PV cell models, namely the single diode RS-, RP- and the two-diode. For the parameter estimation techniques, both the analytical and the soft computing approach are covered. A critical evaluation is carried out to summarize the performance of the models, while at the end, a summary of the future trend and direction of research is given. Since the literature on this subject is very large and dispersed, the availability a single cohesive and comprehensive document on the subject matter is crucial in order to piece the information together and understand the bigger picture. Therefore it is envisaged that this work will be convenient for new entrants as well as experienced researchers and practitioners to update their knowledge in the latest development in the area of PV modelling and simulation. © 2015 Elsevier Ltd.


Hermawan H.,University of Technology Malaysia | Mantovani D.,Laval University
Applied Mechanics and Materials | Year: 2013

Biodegradable metals have been proposed for temporary implants such as coronary artery stent and internal bone fixators. During implantation, a stent is inserted and expanded by using a catheter into a narrowed coronary artery and is subjected to mechanical stress in a corrosive body fluid environment, a condition where stress corrosion cracking may occur. This letter reports an experimental work to verify the susceptibility of Fe-35Mn alloy, a proposed alloy for biodegradable coronary stent, to stress corrosion cracking under a pseudo-physiological condition. © (2013) Trans Tech Publications, Switzerland.


Saad M.S.,University Malaysia Perlis | Jamaluddin H.,University of Technology Malaysia | Darus I.Z.M.,University of Technology Malaysia
International Journal of Innovative Computing, Information and Control | Year: 2012

This paper presents the implementation of PID controller tuning using two modern heuristic techniques which are differential evolution (DE) and genetic algorithm (GA). The optimal PID control parameters are applied for a high order system, system with time delay and non-minimum phase system. The performance of these techniques is evaluated by setting their objective functions as mean square error (MSE) and integral absolute error (IAE). The reliability between DE and GA in consistently maintaining minimum MSE is studied. The performance of the PID control systems tuned using GA and DE methods are also compared with Ziegler-Nichols method. © 2012 ICIC International.


Ishaque K.,University of Technology Malaysia | Ishaque K.,Karachi Institute of Economics & Technology | Salam Z.,University of Technology Malaysia | Amjad M.,University of Technology Malaysia | Mekhilef S.,University of Malaya
IEEE Transactions on Power Electronics | Year: 2012

This paper proposes an improved maximum power point tracking (MPPT) method for the photovoltaic (PV) system using a modified particle swarm optimization (PSO) algorithm. The main advantage of the method is the reduction of the steady-state oscillation (to practically zero) once the maximum power point (MPP) is located. Furthermore, the proposed method has the ability to track the MPP for the extreme environmental condition, e.g., large fluctuations of insolation and partial shading condition. The algorithm is simple and can be computed very rapidly; thus, its implementation using a low-cost microcontroller is possible. To evaluate the effectiveness of the proposed method, MATLAB simulations are carried out under very challenging conditions, namely step changes in irradiance, step changes in load, and partial shading of the PV array. Its performance is compared with the conventional Hill Climbing (HC) method. Finally, an experimental rig that comprises of a buck-boost converter fed by a custom-designed solar array simulator is set up to emulate the simulation. The software development is carried out in the Dspace 1104 environment using a TMS320F240 digital signal processor. The superiority of the proposed method over the HC in terms of tracking speed and steady-state oscillations is highlighted by simulation and experimental results. © 2012 IEEE.


El Enshasy H.A.,University of Technology Malaysia | El Enshasy H.A.,City of Scientific Research and Technology Application | Hatti-Kaul R.,Lund University
Trends in Biotechnology | Year: 2013

For centuries, mushrooms have been used as food and medicine in different cultures. More recently, many bioactive compounds have been isolated from different types of mushrooms. Among these, immunomodulators have gained much interest based on the increasing growth of the immunotherapy sector. Mushroom immunomodulators are classified under four categories based on their chemical nature as: lectins, terpenoids, proteins, and polysaccharides. These compounds are produced naturally in mushrooms cultivated in greenhouses. For effective industrial production, cultivation is carried out in submerged culture to increase the bioactive compound yield, decrease the production time, and reduce the cost of downstream processing. This review provides a comprehensive overview on mushroom immunomodulators in terms of chemistry, industrial production, and applications in medical and nonmedical sectors. © 2013 Elsevier Ltd.


Yousefi M.,University of Tenaga Nasional | Darus A.N.,University of Technology Malaysia | Yousefi M.,Federal University of Minas Gerais | Hooshyar D.,University of Malaya
Applied Thermal Engineering | Year: 2015

The complicated task of design optimization of compact heat exchangers (CHEs) have been effectively performed by using evolutionary algorithms (EAs) in the recent years. However, mainly due to difficulties of handling extra variables, the design approach has been based on constant rates of heat duty in the available literature. In this paper, a new design strategy is presented where variable operating conditions, which better represent real-world problems, are considered. The proposed strategy is illustrated using a case study for design of a plate-fin heat exchanger though it can be employed for all types of heat exchangers without much change. Learning automata based particle swarm optimization (LAPSO), is employed for handling nine design variables while satisfying various equality and inequality constraints. For handling the constraints, a novel feasibility based ranking strategy (FBRS) is introduced. The numerical results indicate that the design based on variable heat duties yields in more cost savings and superior thermodynamics efficiency comparing to a conventional design approach. Furthermore, the proposed algorithm has shown a superior performance in finding the near-optimum solution for this task when it is compared to the most popular evolutionary algorithms in engineering applications, i.e. genetic algorithm (GA) and particle swarm optimization (PSO). © 2015 Elsevier Ltd. All rights reserved.


Mat Tokit E.,Hang Tuah University | Yusoff M.Z.,University of Tenaga Nasional | Mohammed H.A.,University of Technology Malaysia
International Communications in Heat and Mass Transfer | Year: 2013

The thermal performance of a single interrupted microchannel heat sink is analyzed. The generality of Brownian motion velocity had been investigated in the range of various Reynolds numbers of 168 to 1200 and Al2O3 nanofluid volume fractions of 0.01 to 0.04. Three different Brownian motion velocities represent the nanoparticle velocity had been modeled in two-phase modeling of nanofluid system. The heat transfer enhancement in this study is investigated in terms of the predicted Nusselt number. As the Reynolds number increased from 200 to 1200, augmentation in average Nusselt number is predicted from 57.64% to 57.97%. At increasing nanofluid volume fraction from 0.01 to 0.04, conduction dominated the heat transfer process results in Nusselt number increment from 3.90% to 5.13%. © 2013 Elsevier Ltd.


Ishaque K.,University of Technology Malaysia | Ishaque K.,Karachi Institute of Economics & Technology | Salam Z.,University of Technology Malaysia | Shamsudin A.,University of Technology Malaysia | Amjad M.,University of Technology Malaysia
Applied Energy | Year: 2012

This paper presents maximum power point tracking (MPPT) of photovoltaic (PV) system using particle swarm optimization (PSO) algorithm. The key advantage of the proposed technique is the elimination of PI control loops using direct duty cycle control method. Furthermore, since the PSO is based on optimized search method, it overcomes the common drawback of the conventional MPPT, i.e. the inability to track the global maximum point (GP) of PV array under partial shading conditions. The algorithm is employed on a buck-boost converter and tested experimentally using a PV array simulator. Ten irradiance patterns are imposed on the array, the majority of which include various partial shading patterns. Compared to the conventional direct duty cycle method, the proposed method performs excellently under all shading conditions. Finally, the performance of the proposed method is tested using the measured data of a tropical country (Malaysia) from 8.00 am to 6.00. pm. For the 10. h (daytime) irradiance and temperature profile, it yields an average MPPT efficiency of 99.5%. © 2012 Elsevier Ltd.


Ishaque K.,University of Technology Malaysia | Ishaque K.,Karachi Institute of Economics & Technology | Salam Z.,University of Technology Malaysia | Mekhilef S.,University of Malaya | Shamsudin A.,University of Technology Malaysia
Applied Energy | Year: 2012

This paper proposes a penalty based differential evolution (P-DE) for extracting the parameters of solar photovoltaic (PV) modules at different environmental conditions. The two diode model of a solar cell is used as the basis for the extraction problem. The analyses carried out using synthetic current-voltage (I-V) data set showed that the proposed P-DE outperforms other Evolutionary Algorithm methods, namely the simulated annealing (SA), genetic algorithm (GA), and particle swarm optimization (PSO). P-DE consistently converges to the global optimum values very rapidly. The performances are evaluated using the well known quality test and student T-tests. Furthermore, the P-DE extraction method is practically validated by six solar modules of different types (multi-crystalline, mono-crystalline, and thin-film). The results were found to be in close agreement with the experimental I-V data set, especially at very low irradiance values. The latter can be very useful in predicting the performance of the solar system under partial shading conditions. The main application of the proposed work is the possibility of developing a highly accurate simulator for solar PV system designer. © 2012 Elsevier Ltd.


Rajesh S.,Anna University | Fauzi Ismail A.,University of Technology Malaysia | Mohan D.R.,Anna University
RSC Advances | Year: 2012

Poly(amide-imide) (PAI) and TiO2 nanoparticle-incorporated poly(ether-sulfone) (PES) asymmetric nanofiltration membranes with an integrally dense skin layer were prepared by diffusion induced phase separation. The prepared membranes were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), pure water flux, water content and contact angle technique to investigate the influence of PAI on the properties of the membranes. Intermolecular interactions between the components in blend membranes were established by ATR-FTIR and microcrystalline morphology was confirmed by XRD. The SEM analysis showed that blend membranes have an integrally dense skin layer adequate for nanofiltration and a spongy sub-layer along the entire membrane cross section. The contact angle measurements indicated that, hydrophilicity of the virgin PES membranes was improved by the addition of PAI and TiO2 nanoparticles due to the preferential orientation of these components towards the membrane surface during immersion precipitation. Surface free energy parameters of the membrane such as surface free energy, interfacial free energy, work of adhesion and spreading coefficient were calculated. The efficiency of these membranes in the separation of mixture solutions of divalent salt and surfactant were found to be improved significantly. Fouling stability of the membranes studied by bovine serum albumin (BSA) as the model foulant revealed improved fouling resistance. Chlorine stability of the modified membranes was also investigated. From the results, it was revealed that low interfacial free energy membranes prepared by the incorporation of PAI and TiO2 nanoparticles may be valuable in fouling stability industrial separations. © 2012 The Royal Society of Chemistry.


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

Montmorillonite (MMT) modified TiO2 nanocomposites were synthesized by single step sol-gel method. The samples were characterized by XRD, FE-SEM, HR-TEM, FT-IR, N2-adsorption-desorption, UV-vis and photoluminescence (PL) spectroscopy. Modification of TiO2 with MMT controlled the crystal growth and produced anatase phase of delaminated TiO2 pillared montmorillonite. The size of TiO2 nanoparticles reduced from 18.73 to 13.87nm after adding MMT, while the surface area and pore volume increased. The UV-vis results identified blue shift in TiO2 band gap for the MMT modified samples. In addition, PL spectroscopy revealed significant inhibition in recombination of photogenerated electron-hole pairs. The performance of MMT modified TiO2 samples for reducing CO2 with H2O to hydrocarbon fuels was investigated. The effects of parameters such as MMT loading on TiO2, H2O/CO2 feed ratios, and reaction temperature on TiO2 photocatalytic activity was studied. Loading MMT on TiO2 enhanced the performance of TiO2 and markedly increased CO2 reduction to C1-C3 hydrocarbon fuels. The highest yield rates produced were 441.5 and 103μmolgcat-1h-1 for CH4 and CO, respectively under UV light irradiations at 20wt.% MMT loading, reactor pressure of 0.20 bars and 393K reaction temperature. These results revealed silicate layers of MMT dispersed in the given TiO2 sol system and vacant d-orbits of the MMT transition metal ions have obvious effect on the photocatalytic activity of TiO2. The possible pathways and reaction mechanisms of CH4 and CO productions were also suggested. Thus, MMT is a potentially attractive material to improve TiO2 as a photocatalyst for application in photocatalytic CO2 reduction. © 2013 Elsevier B.V.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2011

Electricity is conceivably the most multipurpose energy carrier in modern global economy, and therefore primarily linked to human and economic development. Energy sector reform is critical to sustainable energy development and includes reviewing and reforming subsidies, establishing credible regulatory frameworks, developing policy environments through regulatory interventions, and creating market-based approaches. Energy security has recently become an important policy driver and privatization of the electricity sector has secured energy supply and provided cheaper energy services in some countries in the short term, but has led to contrary effects elsewhere due to increasing competition, resulting in deferred investments in plant and infrastructure due to longer-term uncertainties. On the other hand global dependence on fossil fuels has led to the release of over 1100 GtCO2 into the atmosphere since the mid-19th century. Currently, energy-related GHG emissions, mainly from fossil fuel combustion for heat supply, electricity generation and transport, account for around 70% of total emissions including carbon dioxide, methane and some traces of nitrous oxide. This multitude of aspects play a role in societal debate in comparing electricity generating and supply options, such as cost, GHG emissions, radiological and toxicological exposure, occupational health and safety, employment, domestic energy security, and social impressions. Energy systems engineering provides a methodological scientific framework to arrive at realistic integrated solutions to complex energy problems, by adopting a holistic, systems-based approach, especially at decision making and planning stage. Modeling and optimization found widespread applications in the study of physical and chemical systems, production planning and scheduling systems, location and transportation problems, resource allocation in financial systems, and engineering design. This article reviews the literature on power and supply sector developments and analyzes the role of modeling and optimization in this sector as well as the future prospective of optimization modeling as a tool for sustainable energy systems. © 2011 Elsevier Ltd. All rights reserved.


Nasef M.M.,University of Technology Malaysia | Nasef M.M.,Malaysia Japan International Institute of Technology | Guven O.,Hacettepe University
Progress in Polymer Science | Year: 2012

Functional copolymers obtained by modification of existing polymers using radiation induced graft copolymerization are attractive materials due to their enhanced separation properties. For further progress, however, copolymers with favorable properties and geometries must be developed to address the growing demands in the field of separation and purification. In this review, the current status of research on the development and applications of radiation-grafted copolymers for separation and purification purposes is presented without neglecting the seminal work that laid the foundation to today's progress. The basic principles of this field including classifications and description of radiation-grafted copolymers with their engineering configurations and operating systems are reviewed. A wide range of diverse separation applications is addressed, covering water production, chemical industry, environmental remediation, biotechnology and biomedicine categories. The emerging applications of the new radiation-grafted materials (membranes, brushes, nanogels and microgels, hydrogels, fibers and monoliths) in separation technology are taken into account. The challenges hindering the utilization of radiation-grafted copolymers to wider commercialization applications are discussed. Future directions in developing and promoting new and advanced radiation-grafted copolymers to address separation challenges and move to new technological fronts are also deliberated. © 2012 Elsevier Ltd.


Kianpour E.,University of Technology Malaysia | Sidik N.A.C.,University of Technology Malaysia | Bozorg M.A.S.M.,Iranian Space Agency ISA
International Journal of Heat and Mass Transfer | Year: 2013

This study was accomplished in order to investigate the effects of different cooling hole configurations on the thermal and flow field characteristics inside a combustor simulator. By using the well-known Brayton cycle, great turbine industries try to extend the inlet temperature and augment engine performance. However the turbine inlet temperature increment creates an extremely harsh environment for the downstream components of the combustor. In this research a three-dimensional representation of Pratt and Whitney aero-engine was simulated and analysed with a commercial finite volume package FLUENT 6.2 to gain fundamental data. The current study has been performed with Reynolds-averaged Navier-Stokes turbulence model (RANS) on internal cooling passages. This combustor simulator combined the interaction of two rows of dilution jets, which were staggered in the streamwise direction and aligned in the span wise direction, with that of film-cooling along the combustor liner walls. The entire findings of the study declare that the greater penetration depth, the thicker the film-cooling layers. Furthermore, in the combustor simulator with more cooling holes, the temperature near the wall and between the jets was slightly increased. Also at the leading edge of the jet, and at the jet-mainstream interface, the gradients of temperature were quite high. © 2013 Elsevier Ltd. All rights reserved.


Mousavi S.M.,University of Technology Malaysia | Naghsh A.,Islamic Azad University at Najafabad | Abu-Bakar S.A.R.,University of Technology Malaysia
Journal of Digital Imaging | Year: 2014

The ever-growing numbers of medical digital images and the need to share them among specialists and hospitals for better and more accurate diagnosis require that patients’ privacy be protected. As a result of this, there is a need for medical image watermarking (MIW). However, MIW needs to be performed with special care for two reasons. Firstly, the watermarking procedure cannot compromise the quality of the image. Secondly, confidential patient information embedded within the image should be flawlessly retrievable without risk of error after image decompressing. Despite extensive research undertaken in this area, there is still no method available to fulfill all the requirements of MIW. This paper aims to provide a useful survey on watermarking and offer a clear perspective for interested researchers by analyzing the strengths and weaknesses of different existing methods. © 2014, Society for Imaging Informatics in Medicine.


Zaib A.,University of Karachi | Zaib A.,University of Technology Malaysia | Shafie S.,University of Technology Malaysia
Journal of the Franklin Institute | Year: 2014

The present investigation is concerned with the effects of thermal-diffusion and diffusion-thermo on an unsteady MHD free convection boundary layer flow with heat and mass transfer of an electrically conducting fluid over a stretching sheet in the presence of strong magnetic field with Hall current, thermal stratification, chemical reaction, heat generation, thermal radiation, Joule heating and viscous dissipation. The transformed nonlinear boundary layer equations are numerically solved by applying Keller-box method. The influence of various embedded flow parameters on the local skin friction, the local Nusselt number and the local Sherwood number has been carefully analyzed through graphs. It is found that the shear stress and the rate of mass transfer increase with an increasing of current density Jh while the reverse trend is observed on the rate of heat transfer. It is also found that the shear stress and the rate of heat transfer increase with an increasing of Sr, whereas the reverse trend is observed on the rate of mass transfer. Further, the shear stress and the rate of mass transfer increase with an increasing of Du while the reverse trend is seen on the rate of heat transfer. The numerical results are compared and found to be in good agreement with previously published results under special cases. © 2013 The Franklin Institute Published by The Franklin Institute All rights reserved.


Yazid I.I.M.,Malaysia Japan International Institute of Technology | Mazlan S.A.,Malaysia Japan International Institute of Technology | Kikuchi T.,Yamagata University | Zamzuri H.,University of Technology Malaysia | Imaduddin F.,University of Technology Malaysia
Materials and Design | Year: 2014

Magnetorheological (MR) damper is a semi-active suspension device that uses MR fluid to produce controllable damper. The mechanical properties of the suspension can be controlled by adjusting the yield stress of MR fluid. This paper presents the design of a new concept for MR damper with a combination of shear and squeeze working modes. Finite Element Method Magnetics (FEMM) was utilized to simulate the magnetic field generated by electromagnetic coils in MR damper. The MR damper was designed and fabricated according to the simulation results. The experimental tests were performed under quasi-static loading in three different conditions; shear mode, squeeze mode and combination of both modes. The results showed that the mixed mode MR damper has produced a unique damping characteristic where in general, a higher damping force has obtained in mixed mode than single mode. © 2013 Elsevier Ltd.


Tahir M.,University of Technology Malaysia | Amin N.S.,University of Technology Malaysia | Amin N.S.,COMSATS Institute of Information Technology
Applied Catalysis B: Environmental | Year: 2015

Indium (In)-doped titanium dioxide (TiO2) nanoparticles were synthesized using a controlled sol-gel method. The structures and properties of the catalysts were characterized by XRD, FE-SEM, TEM, XPS, BET, UV-vis and PL spectroscopy. Indium, present over the TiO2 in metal state, inhibited crystal growth and produced anatase phase of mesoporous TiO2 nanoparticles. Doping In in TiO2 also increased the surface area and enlarged the band gap. The photocatalytic activities of In-doped TiO2 nanoparticles were considerably improved for CO2 reduction with H2O vapors in a cell type photoreactor. CO was observed as the main product over TiO2, but doping In in TiO2 remarkably increased the CH4 yield. CH4 production rate over 10wt.% In-doped TiO 2 was 7.9-fold higher than the bare TiO2 at 100°C and CO2/H2O ratio of 1.43. In addition, C1-3 higher hydrocarbons namely C2H4, C2H6, C3H6 and C3H8 were detected in the product mixture. The enhanced photoactivity in mesoporous In-doped TiO2 nanoparticles can be attributed to interfacial transfer of photogenerated charges, which led to effective charge separation and inhibited recombination of photogenerated electron-hole (e-/h+) pairs. Langmuir-Hinshelwood model, developed to investigate reaction rate parameters, fitted well with the experimental data. © 2014 Elsevier B.V.


Liew W.H.,University of Technology Malaysia | Hassim M.H.,University of Technology Malaysia | Ng D.K.S.,University of Selangor
Journal of Cleaner Production | Year: 2014

Biofuel is recognised as an important renewable and sustainable energy source to substitute fossil fuel. To date, biofuel has been evolved from first to fourth generation and they are mainly differed in feedstock and production technologies. Along with the evolution, various studies on different sustainability criteria have been conducted. In this review paper, the state of the art of technologies and assessment methods on economic performance, safety, health and environment (SHE) as well as social impact for biofuel production are reviewed. In addition, this review paper also evaluates the typical methodological framework used for systematic assessment during early process design phase. As conclusion, to establish the highest sustainability in biofuel production, continuous research and development on all sustainability-related aspects are very much needed. © 2014 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.


Tahir M.,University of Technology Malaysia | Tahir M.,COMSATS Institute of Information Technology | Amin N.S.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2013

Energy crisis and threats of global warming has accelerated the thrust for new renewable energy resources. Recycling greenhouse gases seems eminently potential to produce sustainable fuels as well as to reduce carbon emission. Various possibilities for implementing low carbon economy drive by practicing phototechnology are reviewed in this paper. In particular, different challenges and applicable solutions for efficient and economical conversion of greenhouse gases to renewable fuels are discussed. The roles of key parameters such as types of reductant, reduction potential, pH of mixture, metal-loaded and supported catalyst on hydrocarbon yield and selectivity are also investigated. Various types of photoreactors and different challenges in the design are also elaborated. It was obvious that modification of semiconductor photocatalyst, optimum operating parameters and suitable photoreactor design are pertinent for efficient CO2 reduction to sustainable hydrocarbon fuels. In view of the current scenario, there are ample opportunities for producing renewable fuels and establishing a sustainable carbon neutral cycle using phototechnology. © 2013 Elsevier Ltd.


Chan S.H.S.,University of Selangor | Chan S.H.S.,University of Technology Malaysia | Wu T.Y,University of Selangor | Juan J.C.,University of Technology Malaysia | Teh C.Y.,University of Selangor
Journal of Chemical Technology and Biotechnology | Year: 2011

The textile industry presents a global pollution problem owing to the dumping or accidental discharge of dye waste-water into waterways, which is having a major impact on the quality and aesthetics of water resources. The World Bank estimates that 17 to 20% of industrial water pollution comes from textile dyeing and treatment. This percentage represents an appalling environmental challenge for clothing designers and other textile manufacturers. Recently, the application of metal oxide semiconductors in the advanced oxidation process (AOP) has gained wide interest for the treatment of dye waste-water owing to its good degradation efficiency, low toxicity and physical and chemical properties. AOP refers to a set of chemical treatment procedures designed to remove organic and inorganic materials from waste-water by oxidation. In this paper, recently developed metal oxide semiconductors are discussed, in which the semiconductors are generally divided into three categories: (i) titanium dioxide; (ii) zinc oxide; and (iii) other metal oxides (such as vanadium oxide, tungsten oxide, molybdenum oxide, indium oxide and cerium oxide). The syntheses and modification methods as well as the efficiency of each category are discussed and analyzed. © 2011 Society of Chemical Industry.


Tahir M.,University of Technology Malaysia | Tahir M.,COMSATS Institute of Information Technology | Amin N.S.,University of Technology Malaysia
Energy Conversion and Management | Year: 2013

Solar conversion of CO2 to hydrocarbon fuels seems promising to reduce global warming for improved sustainability. Solar energy, as direct solar irradiations, is excessively available and it is imperious to utilize it for solar fuel production. This review paper is organized to discuss recent innovations and potential applications of phototechnology to recycle CO 2 via visible light responsive (VLR) TiO2-based photocatalyst. In this perspective various enhancement methods such as doping with metals and non-metals and sensitization to expand TiO2 band gap toward visible region are critically discussed. This review paper also presents applications of VLR photocatalysts, advances in photoreactors, and future prospects of VLR based technology for conversion of CO2 to hydrocarbon fuels. The findings of this study revealed both metals and non-metals could improve TiO2 photoactivity, but non-metals and especially co-metals were more efficient. The combination of co-metals with sensitizers exhibited much higher CO, CH4 and CH3OH yield rates. Among photocatalytic reactors, optical fibers and monolith photoreactors are more efficient because of their efficient light harvesting potential. Although the progress in CO2 reduction to fuels is encouraging, further considerations are required for commercialization purposes. © 2013 All rights reserved.


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 improved quantum efficiency indicated photon energy was efficiently utilized in the microchannel monolith reactor. A simple kinetic model based on Langmuir-Hinshelwood model, developed to incorporate coupled effect of adsorptive photocatalytic reduction and oxidation process, fitted-well with the experimental data. © 2013 Elsevier B.V.


Bazmi A.A.,University of Technology Malaysia | Bazmi A.A.,COMSATS Institute of Information Technology | Zahedi G.,University of Technology Malaysia | Hashim H.,University of Technology Malaysia
Renewable and Sustainable Energy Reviews | Year: 2011

It has been broadly accepted worldwide that global warming, indeed, is the greatest threat of the time to the environment. Renewable energy (RE) is expected as a perfect solution to reduce global warming and to endorse sustainable development. Progressive release of greenhouse gases (GHG) from increasing energy-intensive industries has eventually caused human civilization to suffer. Realizing the exigency of reducing emissions and simultaneously catering to needs of industries, researchers foresee the RE as the perfect entrant to overcome these challenges. RE provides an effective option for the provision of energy services from the technical point of view while biomass, a major source of energy in the world until before industrialization when fossil fuels become dominant, appears an important renewable source of energy and researches have proven from time to time its viability for large-scale production. Being a widely spread source, biomass offers the execution of decentralized electricity generation gaining importance in liberalized electricity markets. The decentralized power is characterized by generation of electricity nearer to the demand centers, meeting the local energy needs. Researchers envisaged an increasing decentralization of power supply, expected to make a particular contribution to climate protection. This article investigates the progress and challenges for decentralized electricity generation by palm oil biomass according to the overall concept of sustainable development. © 2010 Elsevier Ltd.


Atta M.,University of Technology Malaysia | Idris A.,University of Technology Malaysia | Bukhari A.,University of Technology Malaysia | Wahidin S.,University of Kuala Lumpur
Bioresource Technology | Year: 2013

Light quality and the intensity are key factors which render microalgae as a potential source of biodiesel. In this study the effects of various intensities of blue light and its photoperiods on the growth and lipid content of Chlorella vulgaris were investigated by using LED (Light Emitting Diode) in batch culture. C. vulgaris was grown for 13days at three different light intensities (100, 200 and 300μmolm-2s-1). Effect of three different light and dark regimes (12:12, 16:08 and 24:00h Light:Dark) were investigated for each light intensity at 25°C culture temperature. Maximum lipid content (23.5%) was obtained due to high efficiency and deep penetration of 200μmolm-2s-1 of blue light (12:12 L:D) with improved specific growth (1.26d-1) within reduced cultivation time of 8days. White light could produce 20.9% lipid content in 10days at 16:08h L:D. © 2013 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.


Chan G.F.,University of Technology Malaysia | Gan H.M.,ScienceVision SB | Ling H.L.,University of Technology Malaysia | Rashid N.A.A.,University of Technology Malaysia
Eukaryotic Cell | Year: 2012

A draft genome sequence of Pichia kudriavzevii M12 is presented here. The genome reveals the presence of genes encoding enzymes involved in xylose utilization and the pentose phosphate pathway for bioethanol production. Strain M12 is also a potential producer of phytases, enzymes useful in food processing and agriculture. © 2012, American Society for Microbiology. 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.


Hassan Z.,University of Technology Malaysia | Shamsudin S.,University of Kuala Lumpur | Harun S.,University of Technology Malaysia
Theoretical and Applied Climatology | Year: 2014

Climate change is believed to have significant impacts on the water basin and region, such as in a runoff and hydrological system. However, impact studies on the water basin and region are difficult, since general circulation models (GCMs), which are widely used to simulate future climate scenarios, do not provide reliable hours of daily series rainfall and temperature for hydrological modeling. There is a technique named as "downscaling techniques", which can derive reliable hour of daily series rainfall and temperature due to climate scenarios from the GCMs output. In this study, statistical downscaling models are used to generate the possible future values of local meteorological variables such as rainfall and temperature in the selected stations in Peninsular of Malaysia. The models are: (1) statistical downscaling model (SDSM) that utilized the regression models and stochastic weather generators and (2) Long Ashton research station weather generator (LARS-WG) that only utilized the stochastic weather generators. The LARS-WG and SDSM models obviously are feasible methods to be used as tools in quantifying effects of climate change condition in a local scale. SDSM yields a better performance compared to LARS-WG, except SDSM is slightly underestimated for the wet and dry spell lengths. Although both models do not provide identical results, the time series generated by both methods indicate a general increasing trend in the mean daily temperature values. Meanwhile, the trend of the daily rainfall is not similar to each other, with SDSM giving a relatively higher change of annual rainfall compared to LARS-WG. © 2013 Springer-Verlag Wien.


Zhou K.-Q.,University of Technology Malaysia | Zain A.M.,University of Technology Malaysia | Mo L.-P.,JiShou University
Expert Systems with Applications | Year: 2015

As with Petri nets (PNs), the state space explosion has limited further studies of fuzzy Petri net (FPN), and with the rising scale of FPN, the algorithm complexity for related applications using FPN has also rapidly increased. To overcome this challenge, we propose a decomposition algorithm that includes a backwards search stage and forward strategy for further decomposition, one that divides a large-scale FPN model into a set of sub-FPN models using both a presented index function and incidence matrix. In the backward phase, according to different output places, various completed inference paths are recognized automatically. An additional decomposition operation is then executed if the "OR" rule exists for each inference path. After analysing the proposed algorithm to confirm its rigor, a proven theorem is presented that calculates the number of inference paths in any given FPN model. A case study is used to illustrate the feasibility and robust advantages of the proposed decomposition algorithm. © 2015 Elsevier Ltd.


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.


Wahidin S.,University of Kuala Lumpur | Wahidin S.,University of Technology Malaysia | Idris A.,University of Technology Malaysia | Shaleh S.R.M.,Universiti Malaysia Sabah
Energy Conversion and Management | Year: 2014

The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production. © 2014 Elsevier Ltd. All rights reserved.


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.


Yunus M.A.M.,University of Technology Malaysia | Mukhopadhyay S.C.,Massey University | Ibrahim S.,University of Technology Malaysia
IEEE Sensors Journal | Year: 2012

The main advantages of electromagnetic sensors can be listed as low-cost, convenient, suitable for in-situ measurement system, rapid response, and high durability. In this paper, the output parameters of the planar electromagnetic sensor have been observed with different kind of water samples at different concentrations. The output parameters have been derived and tested to be incorporated with independent component analysis (ICA) and used as inputs for an analysis model. The analysis model targeted to estimate the amount of nitrate contamination in water samples with the assistance of ICA based on FastICA fixed point algorithm under the contrast functions of pow3, tanh, gauss, and skew. Nitrates sample in the form of ammonium nitrates (NH 4NO 3), each of different concentration between 5 mg and 20 mg dissolved in 1 litre of deionized water (Milli-Q) was used as one of the main references. The analysis model was tested with eight sets of mixed NH 4NO 3 and (NH 4) 2HPO 4 water samples. It is seen from the results that the model can acceptably detect the presence of nitrate added in Milli-Q water and capable of distinguishing the concentration level in the presence of other type of contamination. The system and approach presented in this paper has the potential to be used as a useful low-cost tool for water sources monitoring. © 2001-2012 IEEE.


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

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


Nair A.K.,National Institute of Technology Karnataka | Isloor A.M.,National Institute of Technology Karnataka |