Papers by Author: Wan Ramli Wan Daud

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Authors: Wong Wai Yin, Wan Ramli Wan Daud, Abu Bakar Mohamad, Abdul Amir Hassan Kadhum, Loh Kee Shyuan, Edy Herianto Majlan
Abstract: Catalysis is the major process involved in fuel cell technology to generate electricity which is known renewable. Generally, fuel cell electrodes utilize platinum supported carbon to catalyze the reactions at both cathode and anode. However, cheaper substitution materials such as nitrogen-doped carbon catalyst have attracted greater attention in recent year due to its significant catalytic activity at cathode in fuel cell. Nitrogen-doped CNT (N-CNT) is believed to allow oxygen reduction reaction (ORR) at cathode to take place which play a role as n-type dopant for electrical conductivity. The objective of this paper is to understand the mechanism of oxygen adsorption on N-CNT using the density-functional theory (DFT). N-CNT with two configurations involve sp2 and sp3 hybridized nitrogen are studied and compared in order to find the most thermodynamically stable N-CNT for sustainable ORR activity in fuel cell. The structural stability is studied through the binding energies of each configurations and the metallic behavior is examined through the energy gaps from the HOMO-LUMO studies. Finally, the adsorption energies and deformation energies of oxygen on N-CNT is discussed. Results revealed that sp3 hybridized N-CNT gives the most stable structure with compatible oxygen adsorption ability.
Authors: Mulyazmi, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: One important aspect to develop fuel cell design is to use the concept of computational models. Mathematical modeling can be used to help research complex, estimates the optimal performance of fuel cells stack, compare several different processes, save costs and time in the investigation. This paper focuses on several reviews of research models to develop the system design of the Proton Exchange Membrane Fuel Cell (PEMFC). Purposes of this study are to determine the factors that affect system performance include: stack of PEMFC system, water management system and Supply of reactants to the PEMFC stack.
Authors: Samaneh Shahgaldi, Zahira Yaakob, Dariush Jafar Khadem, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: In recent years, one dimensional nanostructure, nanowires, nanofibers with unique properties have been a subject of intense research due to reduction of devise dimension, potential properties from the re-arrangement at the molecular level and high surface area. There are many methods for synthesize such as laser ablation, chemical vapour deposition, solution method micro pulling down method but all these method faced to the major disadvantages of being complicated with long wasting time and relatively high expense . The electrospinning recently used for producing ceramic, metal, and carbon nanofibers. In this report, we incorporate palladium into silica nanofibers for the first time, and the effect of doping of palladium into the silica nanofibers is investigated. The different ratio of palladium to silica and comparing with silica nanofibers is also reported. The composition, morphology, structure and surface area of silica, and silica palladium nanofibers were investigated by thermo gravimetric analysis (TGA), x-ray diffraction (XRD), scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FT-IR), and Micromeriics. To the best of our knowledge, investigation on characteristic on Silica palladium nanofibers has not been reported up to now. The result reveal that the silica nanofibers compare to silica doped with palladium have lower diameter, and also by increasing the temperature above 600 °C, the reduction in length of nanofibers happened. High surface area of silica palladium nanofibers can be one of the promising materials for hydrogen storage.
Authors: Dariush Jafar Khadem, Zahira Yaakob, Samaneh Shahgaldi, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: Metal and Metal oxide nanofibers have different potential to play an essential role in a series of application, among them copper and copper oxide nanostructures is a promising semiconductor material with potential applications in many field. In this paper, electrospinning method via sol-gel was used to fabricate copper and copper oxide nanofibers. Synthesize of copper and copper oxide nanofibers and also effect of calcinations temperature on morphology investigated by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).
Authors: Hakim Lukman, Zahira Yaakob, Ismail Manal, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: The need and development of cleaner and greener alternative technologies using the heterogeneous catalytic system in the synthesis of fuel is very important. In this work hydrogen production via steam reforming of glycerol (C3H8O3) was carried out over nickel supported on hydroxyapatite [Ca5(PO4)3(OH)] as a biomaterial catalyst. The time reaction is carried out for 240 minutes in a fixed-bed reactor fixed at 600 oC and atmospheric pressure with the water-to-glycerol feed ratio of 8:1. Catalysts were prepared by mean of impregnation and sol-gel method with varied nickel loadings (3, 6, 9, 12 %) on hydroxyapatite. The catalysts were characterized by BET surface area, X-ray diffraction, and SEM-EDX techniques. It is found that 3 wt% of nickel loading prepared via sol-gel method exhibit the higher hydrogen production rates (63.62 % - 74.16 %) in comparison to the other nickel loadings.
Authors: Raharjo Jarot, Andanastuti Muchtar, Wan Ramli Wan Daud, Norhamidi Muhamad, Edy Herianto Majlan
Abstract: Composite electrolytes made of samarium-doped cerium (SDC, Ce0.8Sm0.2O1.9) and (67 mol% Li/ 33mol% Na)2CO3 carbonate salts were investigated in relation to their structure, morphology and porosity of the electrolyte. The fabrication of the SDC–(Li/Na)2CO3 composite electrolytes were achieved in two steps: step (1) preparation of the samarium-doped cerium powders by sol-gel; step (2) mixing of the samarium-doped cerium with carbonates in various compositions by solid state reaction. The electrolyte pellets were compacted at different pressures (25 and 50 MPa) and sintered at 600oC, 700oC and 800oC. The XRD results demonstrated that the introduction of carbonates did not change the SDC phase structure. FESEM images showed that the carbonate component was amorphous and well distributed in the SDC. The lowest porosity (2.92%) was achieved for samples with carbonate content of 30% (SDC7030) sintered at 800oC and cold pressed at 50MPa.
Authors: Samaneh Shahgaldi, Zahira Yaakob, Norazrina Mat Jali, Dariush Jafar Khadem, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: Electrospun Poly (vinylidene fluoride) (PVdF) fine fiber of 100-300 nm in diameter in ribbon shape was synthesized through the electrospinning process via sol-gel. In order to synthesize infusible nanofibers all processing of dehydrofluorination and carbonization was investigated. Iron nanoparticles was doped with PVDF nanofibers in order to be effective in surface area, and porosity to increase the hydrogen storage. The composition, morphology, structure and surface area of PVDF/Iron Oxide nanofibers were investigated by thermo gravimetric analysis (TGA) to determinate the temperature of possible decomposition and crystallinity, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Micromeritics (ASAP2020) used to study the textural properties of the sample, like surface area, total pore volume, and micro pore volume. The result shows that the PVDF without dehydrofluorination treatment for infusibility become melt at around 160 °C. By adding the iron oxide nanoparticles as a catalyst it can improve the characteristic of the carbon fiber for hydrogen storage. In best of our knowledge, PVDF doping with iron oxide investigated for first time.
Authors: Hakim Lukman, Zahira Yaakob, Ismail Manal, Wan Ramli Wan Daud
Abstract: Nickel-hydroxyapatite as biomaterial catalysts exhibited high activity and selectivity in glycerol steam reforming. The catalytic steam reforming of glycerol (C3H8O3) for the production of hydrogen is carried out over nickel supported on hydroxyapatite [Ca5(PO4)3(OH)] catalyst at 600 oC with atmospheric pressure and 120 minute time reaction. The catalysts were prepared by mean of wet impregnation method and varied nickel loadings (3, 6, 12 %) on hydroxyapatite. It is found that the 3% wt% Ni/HAP show higher hydrogen production rate over the other nickel loadings on hydroxyapatite, which is correlated with Ni/HAP catalyst surface area measured by BET adsorbtion and morphology of catalysts. Glycerol steam reforming with water-to-glycerol feed ratio 8/1 much more hydrogen production (77-82%) compared feed ratio 4/1. The catalysts were characterised by BET surface area and SEM-EDX techniques.
Authors: Misran Erni, Mat Hassan Nik Suhaimi, Wan Ramli Wan Daud, Edy Herianto Majlan, Kurniawan Miftah
Abstract: Flooding and membrane dehydration are phenomena that must be avoided in a proton exchange membrane fuel cell (PEMFC) operation. It needs a sufficient knowledge about water transport behaviors. Electro-osmotic drag and back diffusion are the dominant water transport mechanisms through the membrane in PEMFC. In this study, the relative humidity (RH) profile along the channel at both anode and cathode sides have been recorded. The experiment was conducted in a single cell PEMFC with single serpentine flow field design. The water content profile was strongly influenced by RH profile thus in turn influenced the electro-osmotic drag coefficient, water diffusion coefficient and back diffusion flux. The operating temperatures of cell also influence those water transport behavior. The temperature was varied at 25, 40, 50 and 60 oC, while the pressure at the anode and the cathode was fixed at 1 bar. The higher the temperature, the smaller the water contents but with higher electro-osmotic drag coefficient, water diffusion coefficient and back diffusion flux. After all, the strategy of using saturated hydrogen and dry air in this study successfully prevents flooding and membrane dehydrating in the system – that are the major problems in PEMFC operation.
Authors: Kurnia Harlina Dewi, Markom Masturah, Wan Ramli Wan Daud
Abstract: Testosterone, the steroid hormone used in sex reversal and as an aphrodisiac, is produced not only by sea cucumber, but many other organisms too. This research was aimed at optimizing conventional extraction of testosterone from sea cucumber, looking at method, type of solvent, solvent ratio, and temperature for isolation. The results showed that extraction by reflux produced the highest testosterone content, followed by soxhlet extraction. The lowest yield was produced by maceration extraction. The solvents selected were acetone, methanol, methanol/chloroform mixture (1:2) and chloroform. The highest result was obtained by methanol/chloroform (0.2728 mg /100g dry weight (dw)), followed by acetone (0.2623 mg), chloroform (0.1606 mg) and methanol (0.0920 mg). Ratios of material:solvent used were 1:1, 1:2 and 1:3 respectively. Results improved as the amount of solvent was increased, so a ratio of 1:3 was most successful and 1:1 least successful. The effects of temperature and time on scale-up reflux extraction were also studied. Scale-up reflux extraction of 3000 ml showed that raising the temperature increases the percentage of sea cucumber extract.
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