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Showing papers by "Universiti Teknologi Malaysia published in 2015"


Journal ArticleDOI
TL;DR: In this article, the status and current trends of energy consumption, CO2 emissions and energy policies in the residential sector, both globally and in those ten countries, were reviewed, and it was found that global residential energy consumption grew by 14% from 2000 to 2011, where population, urbanization and economic growth have been the main driving factors.
Abstract: 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.

1,212 citations


Journal ArticleDOI
TL;DR: In this paper, the authors consider sustainable competitive advantage, reputation, and customer satisfaction as three probable mediators in the relationship between CSR and firm performance, and conclude that only reputation and competitive advantage mediate the relationship.

1,037 citations


Journal ArticleDOI
TL;DR: Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes, to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.
Abstract: The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.

988 citations


Journal ArticleDOI
TL;DR: In this paper, the authors highlight the recent development of advanced membrane technology such as surface modification, addition of inorganic particles in polymer membrane and the development of ceramic membranes and discuss the effect of operating parameters on the membrane performance.

933 citations


Journal ArticleDOI
TL;DR: This study reviewed a total of 403 papers published from 1994 to 2014 in more than 150 peer reviewed journals and indicated that, in 2013, scholars have published papers more than other years.
Abstract: Two decades was systematically reviewed on fuzzy MCDM techniques from 1994 to 2014.The database for review was 403 papers from more than 150 high-ranking journals.403 scholarly papers were grouped in four different main fields.Papers were classified based on utilizing, developing and proposing research papers. 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.

724 citations


Journal ArticleDOI
TL;DR: In this paper, the more recent methods for the removal of dyes from water and wastewater have been discussed, and the performance and special features of each technique are also presented, as well as the advantages and limitations of each method.
Abstract: Dyes are an important class of organic pollutants and are well known for their hazardous effects on aquatic life in general and human beings in particular. In order to reduce the negative effects of dye contaminated wastewater on humans and the environment, the wastewater must be treated carefully before discharge into main streams. Advances in science and technology have led to the evolution of several techniques for the removal of dyes from industrial and domestic effluents. In this review, the more recent methods for the removal of dyes from water and wastewater have been discussed. Wastewater treatment techniques such as adsorption, oxidation, flocculation–coagulation, membrane filtration and biological treatment have been highlighted. In addition, efforts were made to review all the available techniques and recently published studies from 2010–2014. Furthermore, the performance and special features of these technologies have been summarised. Advantages and limitations of each technique are also presented. A thorough literature survey revealed that chemical oxidation, adsorption, and biological treatments have been the most frequently investigated techniques for dye removal over the past few years.

723 citations


Journal ArticleDOI
11 Sep 2015
TL;DR: The results of this study indicated that in 2013 scholars have published articles more than in other years, and energy, environment and sustainability were ranked as the first areas that have applied MCDM techniques and approaches.
Abstract: Multiple criteria decision-making (MCDM) is considered as a complex decision-making (DM) tool involving both quantitative and qualitative factors. In recent years, several MCDM techniques and approaches have been suggested to choosing the optimal probable options. The purpose of this article is to systematically review the applications and methodologies of the MCDM techniques and approaches. This study reviewed a total of 393 articles published from 2000 to 2014 in more than 120 peer reviewed journals (extracted from Web of Science). According to experts’ opinion, these articles were grouped into 15 fields. Furthermore, these articles were categorised based on authors, publication date, name of journals, methods, tools, and type of research (MCDM utilising research, MCDM developing research, and MCDM proposing research). The results of this study indicated that in 2013 scholars have published articles more than in other years. In addition, the analytic hierarchy process (AHP) method in the individual tool...

704 citations


Journal ArticleDOI
TL;DR: In this paper, a review highlights the fundamental physical properties of PMMA, coupled with experimental evidence of its essential chemistry, such as solubility, hydrolysis, grafting, combustion reactions, reactions with amines, and thermal decomposition.
Abstract: Advances in the use of poly (methyl methacrylate) (PMMA) have opened up a wide range of applications in the field of nanotechnology. The knowledge of the properties of PMMA has contributed a lot to the recent boosts in the synthesis, modification, and applications of the polymer. However, there is a need to condense these developments in the form of an article for better understanding and easy access. This review highlights the fundamental physical properties of PMMA, coupled with experimental evidence of its essential chemistry, such as solubility, hydrolysis, grafting, combustion reactions, reactions with amines, and thermal decomposition. The recent developments in the applications of PMMA in biomedical, optical, solar, sensors, battery electrolytes, nanotechnology, viscosity, pneumatic actuation, molecular separations, and polymer conductivity were also revealed.

649 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the existence of the environmental Kuznets curve (EKC) hypothesis in Vietnam during the period 1981-2011 and established a pollution model by applying the Autoregressive Distributed Lag (ARDL) methodology.

622 citations


Journal ArticleDOI
TL;DR: The overview of the available methods to study cell adhesion through attachment and detachment events was discussed, which included the cell population and single cell approach.
Abstract: Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events.

620 citations


Journal ArticleDOI
TL;DR: In this paper, a review of organic phase change materials (PCMs) is presented, focusing on three aspects: the materials, encapsulation and applications of organic PCMs, and providing an insight on the recent developments in applications of these materials.

Journal ArticleDOI
TL;DR: An overview of the recent development in the production of activated carbon electrodes from agricultural waste biomass for application in supercapacitors is presented in this article, where the effects of activating methods (physical, chemical and microwave-induced) and conditions on the properties of activated carbons are reviewed.
Abstract: An overview of the recent development in the production of activated carbon electrodes from agricultural waste biomass for application in supercapacitors is presented. The use of agricultural waste biomass as precursor for the production of activated carbons has been on the increase lately because it is cheap, readily available and also viewed as a veritable way of combating waste disposal problem in the agricultural industries. The effects of activating methods (physical, chemical and microwave-induced) and conditions on the properties of activated carbons are reviewed. The survey of articles published in the last decade indicates the viability of biomass active carbons being used as electrodes in supercapacitors. Under optimum process conditions, active carbons with specific capacitance as high as 374 F g−1 and high-rate long-cycle stability at 4 A g−1 have been produced. In this review, the influence of surface modification on activated carbon properties is also discussed. From the survey literature, it can be seen that the changes in surface chemistry and the introduction of specific surface functionalities on the surface of activated carbons impacted more on the electrochemical properties than the physiochemical properties of the activated carbons.

Journal ArticleDOI
TL;DR: This review attempts to give the readers insights into the difficulties of incorporating inorganic nanomaterials into the organic PA layer whose thickness usually falls in a range of several-hundred nanometers and shows new possible approaches to overcome these challenges in TFN membrane fabrication.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the environmental Kuznets curve (EKC) hypothesis using a country's ecological footprint as an indicator of environmental degradation, and the results 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.

Journal ArticleDOI
TL;DR: In this article, a review of recent developments in this area, with emphases on catalytic reactivity and its physicochemical properties and reaction mechanism, and fundamental strategies for the rational design of materials for effective transformation of CO2 to methane with the help of H2 and power sources.

Journal ArticleDOI
TL;DR: In this article, the authors conduct a survey on several published valence change resistive switching memories with a particular interest in the I-V characteristic and the corresponding conduction mechanism.
Abstract: Resistive switching effect in transition metal oxide (TMO) based material is often associated with the valence change mechanism (VCM). Typical modeling of valence change resistive switching memory consists of three closely related phenomena, i.e., conductive filament (CF) geometry evolution, conduction mechanism and temperature dynamic evolution. It is widely agreed that the electrochemical reduction-oxidation (redox) process and oxygen vacancies migration plays an essential role in the CF forming and rupture process. However, the conduction mechanism of resistive switching memory varies considerably depending on the material used in the dielectric layer and selection of electrodes. Among the popular observations are the Poole-Frenkel emission, Schottky emission, space-charge-limited conduction (SCLC), trap-assisted tunneling (TAT) and hopping conduction. In this article, we will conduct a survey on several published valence change resistive switching memories with a particular interest in the I-V characteristic and the corresponding conduction mechanism.

Journal ArticleDOI
TL;DR: In this paper, a review of the important works on the modelling and parameters estimation of photovoltaic (PV) cells for PV simulation is presented, which 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.

Journal ArticleDOI
TL;DR: In this paper, the current scenario of the plastic recycling technology is reviewed in order to provide the reader with an in-depth analysis with respect to the pyrolysis of plastic waste as obtained in the current recycling technology.
Abstract: Due to the depleting fossil fuel sources such as crude oil, natural gas, and coal, the present rate of economic growth is unsustainable. Therefore, many sources of renewable energy have been exploited, but the potentials of some other sources such as plastics waste are yet to be fully developed as full scale economic activity. Development and modernization have brought about a huge increase in the production of all kinds of plastic commodities, which directly or indirectly generate waste due to their wide range of applications coupled with their versatility of types and relatively low cost. The current scenario of the plastic recycling technology is reviewed in this paper. The aim is to provide the reader with an in-depth analysis with respect to the pyrolysis of plastic waste as obtained in the current recycling technology. As the calorific value of the plastics is comparable to that of hydrocarbon fuel, production of fuel from plastic waste would provide a good opportunity to utilize the waste as a better alternative to dumpsites. Different techniques of converting plastics waste into fuel including thermal and catalytic pyrolysis, microwave-assisted pyrolysis and fluid catalytic cracking are discussed in detail. The co-pyrolysis of plastics waste with biomass is also highlighted. Thus, an attempt was made to address the problem of plastic waste disposal as a partial replacement of the depleting fossil fuel with the hope of promoting a sustainable environment.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a method to improve the efficiency of the PO only several lines of additional software codes are to be embedded into the conventional P&O MPPT control program.

Journal ArticleDOI
TL;DR: In this paper, the authors highlight the historical milestones achieved in reverse osmosis (RO) technology in terms of membrane performance, the developments seen over the last few years and the challenges perceived.

Journal ArticleDOI
TL;DR: In this article, a detailed overview of current knowledge on the surface modification of nanocellulose has been provided also to encourage the emergence of preparation of cellulose derivative nanocrystals with controlled morphology, structure and properties, so that enable positive development of biocompatible, renewable and sustainable reinforcing materials for polymer composites field.
Abstract: In the last few decades, the usages of plant sources-based stiff fillers as reinforcement material in polymer composites have attracted significant interests of researchers. The crystalline part of the semicrystalline cellulose chains as found in the plant cell walls represents the most highly potential reinforcing agents for polymer. This review systematically covers the extraction of nano-sized cellulose crystals from plant cell wall which involving the applications of several highly effective techniques. The topic about the derivation of products functionality at each stage as well as their influences on the final reinforcing capability is also covered. Apart from these, a detailed overview of current knowledge on the surface modification of nanocellulose has been provided also. Inasmuch, this paper is desired to encourage the emergence of preparation of cellulose derivative nanocrystals with controlled morphology, structure and properties, so that enable positive development of biocompatible, renewable and sustainable reinforcing materials for polymer composites field.

Journal ArticleDOI
TL;DR: A quantitative evaluation model to measure the uncertainty of GSCM activities is developed and an approach based on Vlsekriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method which is an extension of intuitionistic fuzzy environment aiming to solve the green multi-criteria decision making (GMCDM) problem is applied.

Journal ArticleDOI
TL;DR: In this paper, the performance of metal oxide thin film electrodes on activated carbon has been evaluated in the context of supercapacitors, showing that metal oxide films will play a major role in super-capacitor technology and are expected to significantly develop the capabilities of these devices in the near future.
Abstract: The electrochemical capacitor (EC), also called as supercapacitor, is an energy storage device possessing a unlimited life-cycle and high power density known to store energy in the double-layer or through supercapacitance as a result of an applied potential. Fundamental values in relation to the major chemical and physical qualities of electrode materials are explained in the following review, with carbon-made electrodes, specially activated carbon highlighted in regards to their improvement of the typical power and energy densities of ECs. Supercapacitive materials, remarkably transition metal oxides are revealed by the potential to further develop EC performance through synergistic effects and asymmetric design. Recently, several chemically deposited metal oxide thin film electrodes as well as ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, iron oxide, ferrites etc., have been evaluated in supercapacitors. This review presents supercapacitor performance data of metal oxide thin film electrodes on activated carbon offered by electroless plating as a suitable, fast and economical technique. The supercapacitors demonstrated the specific capacitance (Sc) principles, which are relatively comparable with bulk electrode values; therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology and are expected to significantly develop the capabilities of these devices in the near future.

Journal ArticleDOI
TL;DR: This research presents the results of the GIS-based statistical models for generation of landslide susceptibility mapping using geographic information system (GIS) and remote-sensing data for Cameron Highlands area in Malaysia and demonstrated that the SMCE model is better in prediction than AHP, WLC and WLC models.
Abstract: Landslide susceptibility mapping using GIS-based statistical models and Remote sensing data in tropical environment

Journal ArticleDOI
TL;DR: Magnetorheological (MR) materials are classified as smart materials due to their responsiveness to external magnetic stimuli as discussed by the authors, and they have led to broad applications in several potential fields.
Abstract: Magnetorheological (MR) materials are classified as smart materials due to their responsiveness to external magnetic stimuli. Intensive research on MR materials has led to broad applications in several potential fields. A solid carrier matrix state called MR elastomer with its exceptional magnetic responsive feature is obtained by merging magnetizable particles within an elastomeric polymer. This integration results in outstanding characteristics on the rheological performances. Special prominence is given to the understanding of the base materials and fabrication as well as the functional behavior through various characterization methods. Broad applications of MREs are also explored to provide a profound market picture and to motivate researchers to develop novel technology. The functional behavior of MREs is briefly explained. The art of the materials provides the current position and mapping of the matrix and filler particles. Types of matrix and particles are mentioned together with the level of the research interest on MREs. Description of the fabrication is provided in simple diagrams as summarized from previous works to enhance the MREs performance. The possible tests to reveal the characteristics of the MREs are delivered with the global experimental setup. The review also explains the applications of MREs as well as discussion on the MREs future promising applications.

Journal ArticleDOI
TL;DR: An integrated approach of rule-based weighted fuzzy method, fuzzy analytical hierarchy process and multi-objective mathematical programming for sustainable supplier selection and order allocation combined with multi-period multi-product lot-sizing problem is proposed in this paper.
Abstract: Within supply chains activities, selecting appropriate suppliers based on the sustainability criteria (economic, environmental and social) can help companies move toward sustainable development. Although several studies have recently been accomplished to incorporate sustainability criteria into supplier selection problem, much less attention has been devoted to developing a comprehensive mathematical model that allocates the optimal quantities of orders to suppliers considering lot-sizing problems. In this research, we propose an integrated approach of rule-based weighted fuzzy method, fuzzy analytical hierarchy process and multi-objective mathematical programming for sustainable supplier selection and order allocation combined with multi-period multi-product lot-sizing problem. The mathematical programming model consists of four objective functions which are minimising total cost, maximising total social score, maximising total environmental score and maximising total economic qualitative score. The prop...

Journal ArticleDOI
TL;DR: In this article, the authors focus on the environmental collaboration, which has been seen as a key relational capability to facilitate the GSCM strategic formulation and execution, and propose a plausible conceptual model to elucidate the relationship between these three variables in the context of Malaysian manufacturing companies.

Journal ArticleDOI
TL;DR: The use of PTC technology in the operational CSP projects is 95.7% and has decreased to 73.4% for the under-construction projects as mentioned in this paper, while the use of TSP technology has reached to 71.43%, compared to 28.57% for PTC.
Abstract: The conventional ways for generating electricity around the world face two main problems, which are gradual increase in the earth׳s average surface temperature (global warming) and depleting fossil fuel reserves. So switching to renewable energy technologies is an urgent need. Concentrating solar power (CSP) technologies are one of renewable technologies that are able to solve the present and future electricity problems. In this paper the historical evolution for the cornerstone plants of CSP technologies to generate clean electricity was reviewed and the current projects worldwide of CSP technologies were presented to show that the CSP technologies are technically and commercially proven and have the possibility for hybridization with fossil fuel or integration with storage systems to sustain continuous operation similar to conventional plants. Among all solar thermal technologies parabolic trough is the most technically and commercially proven. It also has the possibility for hybridization since it is proven by operating in several commercial projects for more than 28 years. It has a high maturity level and able to provide the required operating heat energy either as a stand-alone or in hybrid systems at the lowest cost and lower economic risks. For this reason, this technology is dominant in the operational and under-construction projects. However, currently there is a trend toward employing the other CSP technologies in the future projects as a result of the improvement in their performance. The use of PTC technology in the operational CSP projects is 95.7% and has decreased to 73.4% for the under-construction projects. Meanwhile, the uses of Fresnel collector (LFC), Tower power (TSP) and Stirling dish (SDC) technologies in the operational projects are 2.07%, 2.24%, and 0% respectively and have increased to 5.74%, 20.82% and 0.052% respectively for the under-construction projects. For the development projects, the use of TSP technology has reached to 71.43%, compared to 28.57% for PTC.

Journal ArticleDOI
TL;DR: The main objective of this paper is to review the possibility of using water hyacinth for the removal of pollutants present in different types of wastewater.

Journal ArticleDOI
TL;DR: In this article, the authors evaluated the energy, economic and environmental impact of waste-to-energy (WTE) for municipal solid waste management in Malaysia and selected an existing landfill in Malaysia as the case study for consideration to adopt the advanced WTE technologies including the landfill gas recovery system (LFGRS), incineration, anaerobic digestion (AD), and gasification.