W.T. Chong

Second generation bioethanol potential from selected Malaysia's biodiversity biomasses: A review

Rising global temperature, worsening air quality and drastic declining of fossil fuel reserve are the inevitable phenomena from the disorganized energy management. Bioethanol is believed to clear out the effects as being an energy-derivable product sourced from renewable organic sources. Second generation bioethanol interests many researches from its unique source of inedible biomass, and this paper presents the potential of several selected biomasses from Malaysia case. As one of countries with rich biodiversity, Malaysia holds enormous potential in second generation bioethanol production from its various agricultural and forestry biomasses, which are the source of lignocellulosic and starch compounds. This paper reviews potentials of biomasses and potential ethanol yield from oil palm, paddy (rice), pineapple, banana and durian, as the common agricultural waste in the country but uncommon to be served as bioethanol feedstock, by calculating the theoretical conversion of cellulose, hemicellulose and starch components of the biomasses into bioethanol. Moreover, the potential of the biomasses as feedstock are discussed based on several reported works.

Enzymatic transesterification for biodiesel production: a comprehensive review

Biodiesel is a type of renewable fuel and a potential alternative for continuously consumed fossil resources. Currently, the method applied for biodiesel production is transesterification which is divided into non-catalyzed reaction, chemical-catalyzed reaction and enzymatic reaction. Enzymatic reaction is more advantageous than the other methods because of its mild reaction conditions, easy product recovery, no wastewater generation, no saponification and higher quality of products. The main component in this reaction is an enzyme called lipase which can catalyze wide variety of substrate including free fatty acids. Two other main raw materials for biodiesel synthesis are oil and acyl acceptor such as alcohol. Biodiesel catalyzed by enzyme is affected by many factors such as lipase specificity, lipase immobilization, oil composition and purity, oil to acyl acceptor molar ratio, acyl acceptors, temperature, and water content. Many methods have been tested to manipulate these factors and improve the enzymatic reaction for biodiesel production. These methods include combination of lipases, enzyme pretreatment, enzyme post treatment, methanol addition technique, use of solvent and silica gel, and reactor design. This paper will critically discuss the three major components of enzymatic production of biodiesel and the methods used to improve enzymatic reaction, as well as a review on its economic evaluation and industrial scale production.

Transport and retention of engineered Al2O3, TiO2, and SiO2 nanoparticles through various sedimentary rocks.

Engineered aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) nanoparticles (NPs) are utilized in a broad range of applications; causing noticeable quantities of these materials to be released into the environment. Issues of how and where these particles are distributed into the subsurface aquatic environment remain as major challenges for those in environmental engineering. In this study, transport and retention of Al2O3, TiO2, and SiO2 NPs through various saturated porous media were investigated. Vertical columns were packed with quartz-sand, limestone, and dolomite grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolet-visible spectrophotometer. It was found that Al2O3 and TiO2 NPs are easily transported through limestone and dolomite porous media whereas NPs recoveries were achieved two times higher than those found in the quartz-sand. The highest and lowest SiO2-NPs recoveries were also achieved from the quartz-sand and limestone columns, respectively. The experimental results closely replicated the general trends predicted by the filtration and DLVO calculations. Overall, NPs mobility through a porous medium was found to be strongly dependent on NP surface charge, NP suspension stability against deposition, and porous medium surface charge and roughness.

A study of production and characterization of Manketti (Ricinodendron rautonemii) methyl ester and its blends as a potential biodiesel feedstock

Globally, more than 350 oil-bearing crops are known as potential biodiesel feedstocks. This study reports on production and characterization of Manketti (Ricinodendron rautonemii) methyl ester and its blends with diesel. The effect of Manketti biodiesel (B5) on engine and emissions performance was also investigated. The cloud, pour and cold filter plugging points of the produced biodiesel were measured at 1, 3 and 5 °C, respectively. However, the kinematic viscosity of the biodiesel generated was found to be 8.34 mm2/s which was higher than the limit described by ASTM D6751 and EN 14214. This can be attributed to the high kinematic viscosity of the parent oil (132.75 mm2/s). Nevertheless, blending with diesel improved this attribute. Moreover, it is observed that at all engine speeds, B5 produced lower brake power (1.18%) and higher brake specific fuel consumption (2.26%) compared to B0 (neat diesel). B5 increased the CO and HC emissions by 32.27% and 37.5%, respectively, compared to B0. However, B0 produced 5.26% higher NO emissions than B5.

Synthesis, characteristics and sonocatalytic activities of calcined γ-Fe2O3 and TiO2 nanotubes/γ-Fe2O3 magnetic catalysts in the degradation of Orange G

In this work, γ-Fe2O3 and TiO2 NTs/γ-Fe2O3 composites with good magnetism and sonocatalytic activity were prepared by a facile polyol method and utilize the principle of isoelectric point method, respectively. The structural and magnetic features of the prepared calcined γ-Fe2O3 and composite catalysts were investigated by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), surface analysis, UV-Vis diffuse reflectance spectra (UV-Vis DRS), vibrating sample magnetometry (VSM) and zeta potential analysis. The effects of calcination temperature on γ-Fe2O3 phase variation, physical properties and sonocatalytic properties were investigated. The porosity, specific surface area, band gap energy and sonocatalytic activity of γ-Fe2O3 were gradually decreased with calcination temperature increased. TiO2 NTs/γ-Fe2O3 with appropriate composition and specific structural features possess synergetic effects such as efficient separation of charge carriers and hydroxyl radicals produced by heterogeneous fenton and fenton-like reactions. This enhanced the sonocatalytic activity for the degradation of Orange G under ultrasonic irradiation. The sonocatalytic reactions obeyed pseudo first-order kinetics. All these information provide insight into the design and development of high-efficiency catalyst for wastewater treatment.

Biodiesel production from Calophyllum inophyllum−palm mixed oil

ABSTRACT The objective of this study is to investigate the biodiesel production from Calophyllum inophyllum −palm mixed oil. The C. inophyllum–palm biodiesel (C. inophyllum palm oil methyl ester, CPME) is first produced by mixing the crude oils at an equal ratio of 50:50 vol%, followed by degumming, acid-catalyzed esterification, purification, and, last, alkaline-catalyzed transesterification. With this systematic procedure, the acid value of the CPME is 0.4 mg KOH/g, resulting in a significant enhancement of oxidation stability (114.21 h). The results indicate that the fatty acid methyl ester composition of the CPME may be the reason for its larger higher heating value (39.4 MJ/kg) and lower kinematic viscosity (4.15 mm2/s). In short, CPME satisfied the ASTM D6751 and EN 14214 standards as a promising alternative fuel in the future.

The Physical and Magnetic Properties of Electrodeposited Co-Fe Nanocoating with Different Deposition Times

Using the electrodeposition process, cobalt-iron (Co-Fe) nanocrystalline coatings were successfully synthesized onto stainless steel in deposition times of 30, 60, and 90 minutes. The temperature used throughout the process was 50°C in an acidic environment of pH 3. By changing the deposition time, physical properties such as phase and crystallographic structure, surface morphology, grain size, microhardness, and magnetic properties of Co-Fe coatings were examined. FESEM micrographs showed that the grain sizes of the coatings were in the range from 57.9 nm to 70.2 nm. Dendrite and irregular shapes were found in the microstructure of Co-Fe nanocoating. The Co-Fe nanocrystalline coating prepared in a deposition time of 90 minutes achieved the highest microhardness of 339 HVN. The magnetic properties associated with Co-Fe nanocoating at longer deposition times show greater coercivity, , and saturation magnetization, , values of 56.43 Oe and 70.45 eμ/g, respectively. The M-H curves for all the Co-Fe coatings exhibited soft ferromagnetic behaviour with narrow hysteresis loops. It was found that increasing the deposition time also improved the microhardness and magnetic properties of Co-Fe nanocoating, which is much needed for long-life high-coercivity magnetic strip card applications.

Novel bufferless photosynthetic microbial fuel cell (PMFCs) for enhanced electrochemical performance

Photosynthetic microbial fuel cells (PMFCs) are novel bioelectrochemical transducers that employ microalgae to generate oxygen, organic metabolites and electrons. Conventional PMFCs employ non-eco-friendly membranes, catalysts and phosphate buffer solution. Eliminating the membrane, buffer and catalyst can make the MFC a practical possibility. Therefore, single chambered (SPMFC) were constructed and operated at different recirculation flow rates (0, 40 and 240 ml/min) under bufferless conditions. Furthermore, maximum power density of 4.06 mW/m2, current density of 46.34 mA/m2 and open circuit potential of 0.43 V and low internal resistance of 611.8 Ω were obtained at 40 ml/min. Based on the results it was decided that SPMFC was better for operation at 40 ml/min. Therefore, these findings provided progressive insights for future pilot and industrial scale studies of PMFCs.

Cost-Benefit Analysis and Emission Reduction of Energy Efficient Lighting at the Universiti Tenaga Nasional

This paper reports the result of an investigation on the potential energy saving of the lighting systems at selected buildings of the Universiti Tenaga Nasional. The scope of this project includes evaluation of the lighting system in the Library, Admin Building, College of Engineering, College of Information Technology, Apartments, and COE Food court of the university. The main objectives of this project are to design the proper retrofit scenario and to calculate the potential electricity saving, the payback period, and the potential environmental benefits. In this survey the policy for retrofitting the old lighting system with the new energy saving LEDs starts with 10% for the first year and continues constantly for 10 years until all the lighting systems have been replaced. The result of the life cycle analysis reveals that after four years, the selected buildings will bring profit for the investment.

Identification of Material Properties of Orthotropic Composite Plate using Hybrid Non-Destructive Evaluation Approach.

Abstract Identification of material properties is one of the key issues in composite materials research. The mechanical properties of composite materials depend on diverse factors such as configuration of the laminates, constituent materials used and production method adopted. Conventional testing approach tends to be time-consuming, expensive and destructive. As an alternative, a rapid, inexpensive, hybrid and non-destructive evaluation approach which utilises experimental modal analysis and finite element analysis is proposed. Experimental modal data which consist of natural frequencies and mode shapes of an orthotropic composite plate are utilised for correlation purpose with its finite element model. This finite element model of the composite plate is continuously updated and achieves less than 5% in difference of natural frequencies and over 70% in modal assurance criterion. Material properties such as Youngs moduli, in-plane shear modulus and Poisson ratio of the composite plate are then successfully determined using the well-correlated FE model.