There are a variety of educational games produced for studies in game-based learning (GBL) with a specific design to achieve the most efficient stage of learning for school students. However, there is a lack of evidence showing the most suitable and effective game element instilled in the GBL STEM application. Most of the papers studied on GBL have proven the effectiveness aspect in other STEM subjects, however very little discussed in the domain of sustainable energy. Thus, this study aimed to analyse the most common game element applied in designing GBL that achieved the best result for students in learning the STEM subjects. Each game element targeted a different kind of learning results such as student’s learning performance, knowledge level, cognitive effect, and enjoyment. A systematic review was conducted following the specification of the PRISMA checklist to examine past studies. After carefully screening the articles, only twelve published articles met the specification. The finding showed that most common game elements included in designing the GBL, dominated by the level of challenges, followed by rewards/items, feedback, clear goal and time pressure. The finding also included the percentage of most STEM subject studied in GBL and the impact from the GBL STEM application. This review hopes to assist researchers in making a better decision when designing a game application for GBL in sustainable energy subject, from the aspect of students’ age and gender.

Keywords: Game-based learning; STEM; Microbial Fuel Cell; School students

The world population is projected to increase by one billion for the next ten years from the year 2016. Unfortunately, global power plants still using non-renewable energy sources. Consumption of fossil fuels harms the environment, while nuclear energy could release a significant amount of radioactive material. Besides the energy issues, the growth in population contributes to the high production of wastewater. Every year, the wastewater treatment industry consumes a high input of energy for treatment purposes. These issues invigorate research interest in microbial fuel cell (MFC) technology that can generate green power electricity while breaking down the organic matter in the wastewater. One of the research advancement in MFC is the air-cathode MFC that is scaled-up friendly due to its simple structure, and ability to utilize the abundance of oxygen in the air as the membrane and scaling up arrangements. Therefore, this review aims to discuss the main positive findings contributing to the recent improvement of air-cathode MFC and the obstacles faced for upscaling.

Keywords: Air-cathode; Microbial Fuel Cell; Power Generation; COD Reduction

Proton exchange membrane fuel cell (PEMFC) is a well-known energy converter that has low greenhouse gases (GHG) emission, low operating temperatures, and high power density. PEMFC operates on hydrogen (H2) as fuel, and oxygen (O2) as oxidant. Inverse electrolysis occurs between the oxidant and the fuel. Then, water (H2O) forms as their by product. Practically, O2 is supplied from the free air which contains not only oxygen but also other gases such as sulphur dioxide (SO2), and nitrogen oxides (NOx). Meanwhile, the H2 fuel may contain traces of carbon monoxide (CO) as a result from its previous reforming process. This makes PEMFC susceptible to disruption from these particles. These contaminating gases from the free air occupy the reacting sites originally meant for O2 and react with hydrogen ions instead of oxygen ions. While minute CO traces from the fuel occupies the reacting sites for H2 and react with oxygen ions instead of hydrogen ions. Consecutively, the energy output from the PEMFC will be short from its expected numerical value hence a less efficient PEMFC. Hence, this paper reviews recent research on PEMFC under the impact of cathode and anode side contaminants via experimental and numerical works. It is found that CO has more effect to the cell compared to CO2. SO2 and CO contaminates the catalyst layer while NOx does not. In addition, PtRu/C shows more resistance to contamination compared to traditional Pt/C. This comparative review serves to find out potentials in improving PEMFC operation and solving its mitigation strategies.

Keywords: Contamination; Fuel Cell; PEMFC

Electrochemical performance optimization of a conventional solid oxide fuel cell (SOFC) has been massively performed with computational fluid dynamic (CFD) modelling but it’s usage in a proton conducting fuel cell (PCFC) is still minimal. PCFC is a category of SOFC but with proton conductor as electrolyte instead of oxygen-ion conductor in a conventional SOFC. The fabrication of high electrochemical performance of PCFC is desirable because of its ability to operate at lower temperature. The objective of this short review study is to explore the possibilities of CFD modelling application to improve electrochemical performance of a PCFC system. Some CFD study that have been done to SOFC and PCFC were reviewed. One main finding from this short review is that the application of CFD modelling in PCFC design optimization is still minimal. There is a lack of studies that focus on the impact of PCFC anode microstructure on transport phenomena of the PCFC; for example on gas diffusion. It was also found that CFD modelling software Ansys Fluent with add-on Fluent SOFC module that is widely applied to conventional oxygen-ion SOFC need to be modify using User Defined Function (UDF) in order to be used in PCFC system.

Keywords: CFD model; SOFC; PCFC; single cell

Metallic bipolar plates tendency to have high contact resistance and corrosion after several times of usage affected performance of a cell in PEMFC stack. This study focused on the interfacial contact resistance (ICR) and corrosion resistance of SUS 316 L bipolar plates using Cr‒C and Nb‒C as coating layer, single stack performance in PEMFC were observed by experimental. The Cr‒C and Nb‒C coating layer acted as protective layer between SUS 316 L bipolar plates. Therefore, coating is a method in preventing the bipolar plates surface material from damage in the acidic environment of PEMFC. To develop corrosion-resistant and high conductivity bipolar plates for PEMFC, the coatings bipolar plates were applied to cell fabrication in comparison with bare SUS 316 L bipolar plates. The SUS 316 L bipolar plates size and electrode area were 50 mm2 and 25 mm2, respectively. The experiment was carried out on a prepared assembled single cell bipolar plates with the commercial membranes, conductive carbon papers and gasket. Initial performance of the single cells using Cr‒C and Nb‒C coatings over SUS 316 L bipolar plates were recorded at a cell voltage between 0.4 to 0.5 V, respectively. In comparison, Nb‒C gives good performance of corrosion resistance and the ICR value as low as 10‒12 A/cm2 and 1.22 mΩ cm−2. Additionally, it gives maximum power density of 137 mW/cm2 at the cell voltage 0.51 V. The lifetime durability of the single cell significantly improved from the uncoated current density of 390 mA/cm2 to 450 mA/cm2 with Nb‒C coating layer.

Keywords: Single stack performance; PEMFC; metal bipolar plates; Cr‒C; Nb‒C

A series of solid polymer electrolyte films, employing 49% poly(methyl methacrylate)(PMMA)-grafted natural rubber (MG49) as polymer host and lithium tertrafluoroborate (LiBF4) as conducting material were prepared by solution casting technique. The films of MG49-LiBF4, MG49-PMMA and MG49-Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP) at the optimum weight percentage of LiBF4 (25 wt.%, 25 wt.% and 30 wt.%) respectively, were characterized using potentiostatic electrochemical impedance spectroscopy (EIS) technique to measure their impedans. The measurements were conducted at the temperature range from 303 K to 403 K. The values of dielectric constant, Ꜫr increases with the increase of ionic conductivity. The dielectric constant, Ꜫr and dielectric loss, Ꜫi decrease with increase in frequency at the low frequency region attributed to the electrode polarization effects, but almost negligible in the high frequency region due to frequency independent. The imaginary part, Mi of electrical modulus are observed increases with frequency. The systems are concluded as ionic conductors by the present of Mi peak in the plot Mi versus frequency. The presence of peaks at certain frequency in the tan δ versus frequency plots of the polymer electrolytes indicate the existence of relaxation of charge in all samples contributed by the ions and polar functional groups.

Keywords: Battery; energy storage; impedance spectroscopy; modified natural rubber; solid polymer electrolytes

Co-Injection Molding Process (2C-PIM) is the extension of powder injection molding (PIM) process which is widely used in manufacturing industry. However, due to two materials being injected, the development of required parts by 2C-PIM can be challenging. Yet, there are many researches that have been done by 2C-PIM process because the process is capable of combining metal-metal, ceramics-metal and ceramics-ceramics. The selections and combinations of materials are depending on the targeted applications. The 2C-PIM process has 4 main processes which are mixing, injection, debinding and sintering. In this paper, SS17-4PH and SS316L were used to conduct the 2C-PIM process. Both materials were mixed with the binder system which is 60 wt.% of palm stearin (PS) and 40 wt.% of polyethylene (PE) to produce as feedstock. The green parts of SS17-4PH and SS316L were prepared by co-injection process. The co-debinding process for these green parts was investigated. Such process was divided into two stages: solvent debinding and thermal debinding. Solvent debinding was conducted with heptane solution at 60 °C. Meanwhile, thermal debinding was conducted at 500 °C for 1 hour holding time and continued with sintering process in the same furnace at 1250 °C. It was found that the binders were 95% removed during solvent co-debinding and such finding is adequate for the co-sintering process based on PIM concept. The co-sintered part was successfully produced and the physical properties of the co-sintered part was observed in order to ensure the bonding is good. Result of SEM image has proved that the co-sintered part of SS17-4PH/SS316L is well bonded.

Keywords: Co-injection molding; powder injection molding; solvent debinding; thermal debinding; brown parts

In this study, a series of amine functionalised silica/OPBI nanocomposite membrane for high-temperature polymer electrolyte fuel cell (HT – PEMFC) application were prepared. In order to provide a better dispersion and improving the interfacial interaction between organic/inorganic materials, polyethyleneimine was immobilised onto the surface of silica before added into poly(4,4’-diphenylether – 5, 5’-bibenzimidazole) (OPBI). Nuclear Magnetic Resonance (NMR) experiment proved the synthesised polymer while Fourier-transform infrared spectroscopy (FTIR) and EDX method used to validate the grafting of the amine derivative to the surface of silica in the polymer matrix. Although a satisfactory dispersion pattern was found on all nanocomposite membrane under scanning electron microscope (SEM) studies, agglomeration pattern was seen at higher loading of functionalised silica nanoparticles. The physicochemical characteristic of the nanocomposite membrane was investigated by using thermogravimetric analysis for high temperature PEMFC application. Lower water uptake and swelling ratio in both water and phosphoric acid (PA) showed by the OPBI / SiPEI with an increasing trend as the amount of SiPEI were increased. Addition of amine functionalised silica into OPBI shows a significant improvement compared to pure OPBI while the thermal stability of the membrane at high temperature region (100 – 200 °C) can be influenced by the loading concentration of the amine functionalised silica.

Keywords: Polybenzimidazole; Nanocomposite; Proton exchange membrane; Surface functionalisation

In this article, field pilot study was undertaken to examine the transport mechanism for total petroleum hydrocarbon remediation in varying concentration using pseudo first order, pseudo second order and intra particle diffusion kinetic models in land farming treatment. Soil samples were artificially contaminated in varying concentration of 1,000 mg/kg (low), 3,000 mg/kg (medium) and 5,000 mg/kg (high) and treated using organic and inorganic fertilizers for a period of 150days which is the duration for effective remediation treatment. The results from the treated samples were subjected to kinetics studies while coefficient of determination (R2) was applied on the residual total petroleum hydrocarbon (TPH) after 150 days of treatment, pseudo first order had R2 values of 0.7898 (low), 0.6776 (medium) and 0.6131 (high). Pseudo second order had R2 values of 0.9737 (low), 0.9467 (medium), 0.7863 (high) while intra particle diffusion had R2 values of 0.9940 (low), 0.9821 (medium) and 0.9489 (high) respectively. The results indicate that intra particle diffusion model best described the kinetics mechanism of TPH remediation using land farming treatment; but when the alteration in the error structure associated with transforming a nonlinear kinetic equation into linear equation is minimized using nonlinear regression optimization procedure, pseudo first order emerged as the best kinetic model having the least sum of errors as 0.000270 (low), 0.000185 (medium) and 0.000278 (high).

Keywords: Hydrocarbon; remediation; treatment; land farming; transport; kinetics

The automotive industry is the main consumer of dual-phase (DP) steels which have relatively impressive mechanical strength. DP steels are also known to have good ductility and load-bearing property because of their hard martensitic microstructure in soft ferrite grains. The main objective of this study is to determine the mechanical behaviour of DP steels with various martensite volume fractions. A heat treatment with an intermediate quenching procedure followed by three different intercritical temperatures is conducted to produce various ferrite–martensite containing DP steels with different martensite volume fractions (V_m). V_m affects the mechanical properties of steel, such as work hardening, ultimate tensile strength, yield strength and hardness. The results of the experiments conducted in this study prove that excellent work hardening and ductility are observed for DP steels with a low amount of martensite phase. Meanwhile, DP steels with high V_m exhibit high tensile strength and hardness with low ductility. Considère criterion is used to analyse the work hardening behaviour of DP steels. Results indicate that a one-stage work hardening takes place in DP steels; according to Considère criterion, instability strain or uniform elongation is also slightly increased by decreasing the martensite volume fraction or increasing the work hardening rate.

Keywords: Dual-phase steel; instability strain; intercritical annealing; intermediate quenching; martensite volume fraction

A composite perovskite Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ-Sm_0.2Ce_0.8O_1.9 carbonate (BSCF-SDCC) coating was investigated to enhance the performance of SUS 430 stainless steel as interconnect material for solid oxide fuel cells (SOFCs). BSCF-SDCC powder was successfully obtained by low-speed wet milling method from commercial BSCF, SDC, and binary carbonates. The developed BSCF-SDCC powder were heat-treated 600 °C for 90 min, and then characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) equipped with energy-dispersive spectroscopy (EDS). FESEM revealed better morphology of BSCF-SDCC powder with heat treatment. However, XRD analysis showed the destruction of BSCF phase in the BSCF-SDCC powder after heat treatment at 600 °C. Moreover, electrophoretic deposition (EPD) of BSCF-SDCC powder in an ethanol-added dispersing agent suspension was investigated under 10 volt 10 minutes by 10 g/l. The coated samples were then heat-treated at 600 °C. The coated samples were characterized by comparing between the samples with and without heat treatment based on XRD, SEM-EDS, and area specific resistance (ASR) analyses. XRD analysis indicated BSCF phases disappeared for the samples with heat treatment. The heat-treated sample performed better coating morphology and fewer pores. The samples underwent 500 hours of air oxidation at 600°C, and ASR was measured by DC 2-point method during in situ oxidation process. The coated sample with heat treatment at 600 °C exhibited excellent low area-specific resistance reading of below 0.1 Ωcm2, which is an essential requirement for interconnect materials. After 500 h of oxidation, the XRD patterns revealed stable phase and maintained good coating morphology.

Keywords: Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ; electrophoretic deposition; interconnect; perovskite coating; solid oxide fuel cell

Enlargement of the transportation industry in developing countries has had a tremendous impact on the advancement of those countries. This advancement has had both positive and negative impacts on society. Drawbacks primarily include the emission of harmful gases from vehicles, traffic overcrowding, and most importantly, injuries, and deaths by traffic accidents, which have increased significantly. This paper focuses on and investigates the human, vehicle and environmental factors affecting road traffic accidents in Lebanon in order to increase the knowledge surrounding how the elements have impacted the increase in accidents in Lebanon. A quantitative method (questionnaire) was used to collect data to understand the behavior of road users, while the relative importance index (RII) was used to analyze the data. The results illustrate that the top three vehicle-related factors that lead to an increase in the accidents in Lebanon according to the respondents are steering wheel defects with an RII of 3.807, mechanical faults with an RII of 3.489 and 2.934 for lack of vehicles among all the groups. Furthermore, the human factors were recognized to have a slight impact on road traffic accidents with the highest RII of 1.719 for failure to follow driving codes. In conclusion, a country’s development not only depends on economic measure, but it is also determined based on how effective the traffic system infrastructure is and the steps taken to minimize injuries.

Keywords: Road traffic accidents; Lebanon; human factors; road factors; traffic congestion

Graphene is one of the best reinforcement materials but have a strong tendency to agglomerate and will affect the final properties of the composite. Effect of mechanical properties with addition of Graphene Nano-platelets (GNPs) in copper through powder injection molding (PIM) process was investigated. 2 feedstocks was prepared, one is Cu 100% and Cu/0.5 vol.% GNPs. Both feedstocks use same powder loading, 62% powder and 38% binder and the binder system used for this study consist of polyethylene glycol (PEG), polymethyl methacrylate (PMMA) and stearic acid (SA). The feedstocks were sonicated, and ball milled using the same parameters and then continue with until injection process. The produced green part strength and density were tested. The main reason to for density testing is to determine either addition of GNPs will affect the composite density The average green density for Cu 100% is 5.835 g/cm3, which is 99.84 % from the theoretical density. Meanwhile for Cu/GNps 0.5%, the average density is 5.874 g/cm3, which is 99.91 % from the theoretical density. For the green strength, the average maximum flexural strength for Cu 100% is 15.29 MPa and 14.32 MPa for Cu/0.5 vol.% GNPs. Even though the density of Cu/GNPs composites decrease with addition of 0.5 vol% GNPs but both sample strength indicates good mechanical properties and suitable for debinding and sintering process.

Keywords: Copper; Graphene; powder injection molding; flexural strength

This work looks into the effect of Steam to Carbon ratio (S:C) on methane (CH4) conversion and hydrogen (H2) yield over coated Nickel Aluminide (Ni3Al) catalyst in micro reactor. The Ni3Al is an intermetallic alloy which known to have good catalytic activity and selectivity. The Ni3Al catalyst precursor was prepared through dip coating technique at 10wt% on top of substrate plate and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), Temperature Programming Reduction (TPR), activated by H2 reduction, and catalytic activity test in steam methane reforming (SMR) reaction in micro reactor at S:C 2, S:C 3 and S:C 4 with 650°C reaction temperature and 300 minutes reaction time. The characterization showed the presence of Ni3Al on top of the coating surface and successfully been activated at 500°C and 46 minutes. The CH4 conversion and H2 yield in the product of the reaction were quantified using the Gas Chromatograph technique. From the series of experiments, it was found that S:C 4 produced the highest methane conversion of 65.56% and S:C 3 produced the highest hydrogen yield of 41.34%. The S:C 2, showed faster and smoother stability trend conversion as early as 180 minutes from the start of the reaction. However, S:C 3 showed the most optimum methane conversion and hydrogen yield and achieved stability trend conversion within the defined reaction time range of 300 minutes. It is inferred that the S:C 3 is the best steam to carbon ratio for the developed catalyst in these settings.

Keywords: Steam to carbon ratio; methane conversion; micro reactor

The profusely used tools of operational management research in lean manufacturing context include roadmap, conceptual model, implementation frameworks, descriptive planning and assessment checklist. Out of these, an implementation framework development in lean manufacturing sector is common, but faces quandary regarding its development, consolidation and validation – thereby confirming the requirement of availability of succinct platform that aids in research methodology development. The aim of this research is to attain a clear research context, achieved accordingly by detailed literature review study that would subsequently aid in developing a generic research methodology design framework. Concomitant to it, the four layers, the layers of research onion were discussed; followed by selection of appropriate methods for development of research methodology in order to arrive at implementation frameworks. It was observed that for the methodology development, the philosophy of pragmatism is highly suitable, followed by abductive logic, in case of technique, mixed mode research is best, whereas in strategy selection, case study strategy is the most suitable due to its multi-functional ability of in-depth operational study. In addition to that, the mixed-mode approach carries the ability of comparative qualitative and quantitative research through longitudinal and cross-sectional case study respectively. Furthermore, the data collection processes were discussed in relevance to the research objective, which culminated in the formation of a detailed research methodology which has been divided into three major stages of research context and approach, framework development and validation, resulting in attaining implementation framework through literature review, longitudinal case study and cross-sectional case study respectively. The major strength and contribution of this research study is the development of one concise research methodology that is considered as the paradigm shift and a clear innovation towards this field.

Keywords: Literature review; research methodology; operational management; implementation framework; lean manufacturing

Hydroxyapatite (HA), a ceramic phosphate with good biocompatibility, has been extensively used in the field of bone replacement, both in orthopedics and in dentistry. Desired molded part of HA is fabricated by using powder injection molding (PIM) method. Powder loading, rheological properties and sintering atmosphere can significantly affect the quality of molded HA. The effect of these factors on the microstructure and mechanical properties of powder injection molded HA were investigated. Different powder loading of HA (54, 55 and 56 vol%), were mixed with binder 40 wt.% of palm stearin and 60 wt.% polyethylene. The temperature injection were set at 150°C, 160°C and 170°C with the pressure injection of 12 bar. The green body were then sintered in the furnace at temperature of 1100°C, 1200°C and 1300°C for 4 hours. Analysis of variance (ANOVA) is used to determine the optimization of injection molding. Based on the analysis, it was found that 56 vol% powder loading, temperature injection at 150°C up to 170°C and 12 bar pressure injection are the optimum parameters for the process of injection molding. Results further demonstrate that the optimum condition involves the specified HA with temperature injection at 170°C and sintered at 1300°C provides the highest hardness value and flexural strength of 690 Hv and 17.75 MPa respectively.

Keywords: Powder injection molding; hydroxyapatite; sintering process; flexural strength

A promising perovskite-type oxide ceramics of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) cathode co-join with BaCe_0.56Zr_0.34Y_0.1O_3-δ (BCZY) as supported electrolyte for proton conducting fuel cell (PCFC) was investigated. The ultrafine LSCF was synthesized via a sol-gel process assisted with functionalized carbon nanotubes (f-CNTs) which served as a dispersing agent (denoted as modified-LSCF). The cathode ink of modified-LSCF was prepared by mixing cathode powder with binder that made up of ethyl cellulose and terpeniol. The cathode slurry was then deposited on both surface of the BCZY electrolyte via a spin coating technique to become a symmetrical half-cell. The half-cell of modified-LSCF│BCZY│modified-LSCF was subjected to Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscope/Energy Dispersive X-ray (SEM/EDX). The EIS data revealed the electrochemical reaction of the cell was a thermally activated process that follow the Arrhenius Law. LSCF incorporated with f-CNTs was effectively decreased the ASR value to 0.22 Ωcm² at 700^oC, compared to 0.31 Ωcm² using pristine-LSCF. The pellet after EIS measurement showed no sign of crack and delamination at cathode/electrolyte interfaces, with optimum porosity obtained using ImageJ software and its elemental composition still preserved as observed by SEM/EDX analyses. Thus, the LSCF assisted with f-CNTs has a good potential to improve the quality of the cathode for high performance PCFC that operated at intermediate temperature.

Keywords: LSCF; symmetrical half-cell; electrical conductivity

Road accidents pose a serious economic and social problems given that the number of fatal accidents continue to rise at the national and international levels. This study investigates the relationship between three road parameters, namely number of lanes, level of service (LOS), and slope, with road accidents. The data for road accidents were obtained from the Police Department – Contingent Headquarters (IPK) Alor Setar, Kedah, the data for roads, namely number of lanes and traffic volume, were obtained from Public Works Department (JKR), while the TanDEM-X Image was provided by the licensed holder. The ArcGIS software 10.5 was used to process the data; this is followed by performing the regression and kernel density estimation to determine the relationship between the parameters with accident cases. The majority of road accidents in Kedah occurred on two-lane roads. LOS is negatively correlated with road accidents, which indicates that less accidents occurred with higher level of flow. Slope is negatively correlated with road accidents, indicating that a smaller number of accidents occurred on roads with higher slope values. Alor Setar and Sungai Petani have been identified as road traffic accident hotspots for the period from 2013 to 2015. In summary, the findings of this study provide the relevant authority such as the Traffic Police with the critical information required to make a better decision when formulating strategies to reduce road traffic accidents.

Keywords: Road accidents; number of lanes; Level of Service (LOS); slope; GIS application

The enormous amount of wastewater generated by restaurants often require some level of treatment before disposal. This is partly achieved by using synthetic coagulants with its attendant environmental risk. This study is aimed at investigating the use of Aluminium Sulphate (AS) and Moringa oleifera (MO) for treating restaurant wastewater (RW). Different doses (0, 50, 100, and 150 mg/l) of the prepared stock solution of AS and MO were applied to 1000 ml of RW collected from a University restaurant. The result showed that the treated sample pH reduced from 7.55 to 6.86 and 7.0 at an optimum dose of 150 and 50 ml for AS and MO while conductivity increased from 1.03 to 2.22 mg/l and 1.74 mg/l for AS and MO, respectively. Turbidity reduced from 44.73 mg/l to 5.20 mg/l for MO and 5.77 mg/l for AS; dissolved oxygen increased from 0.35 to 0.51 mg/l and 0.70 mg/l for MO and AS; Magnesium reduced from 21.11 to 14.77 mg/l for MO, but increased to 29.07 mg/l for AS; Zinc increased from 1.19 to 6.15 mg/l for MO and 7.10 mg/l for AS, while Calcium increased from 2.02 mg/l to 5.09 mg/l for MO, and 3.09 mg/l for AS. The MO seed extract achieved a better reduction of pH and turbidity at higher dose while no distinct trend was observed in all the parameters when AS was applied. Doses of MO seed extract can be further optimized and applied as a low cost option for RW treatment.

Keywords: Moringa oleifera; aluminium sulphate; natural coagulant; restaurant wastewater; dosage

Carbon nanotubes (CNTs) have the advantage to improve electrochemical fuel cell reactions by increasing the dispersion of nanoparticles as well as having high strength in mechanical and electrical properties. Therefore, this study presents the comparison of nitrogen doped CNT and other doping heteroatom on CNT as a catalyst support for application in the Direct Liquid Fuel Cell (DLFC). The doping ratio in CNT was conducted to determine the effect of the oxygen reduction reaction. In addition, the effect of CNT diameter in oxygen adsorption also has been tested. The models and calculations were done using density functional theory (DFT). The result showed that the ratio of N/C is decreases as the diameter of CNT decreases. The value is even dropped as the unit cell is increased to 1x1x2. The band gap value of CNT before doping is higher compared to after nitrogen doping. While increasing the diameter of doped CNT has increased the mulliken charge distribution and thus make the model more stable. In the adsorption energy of molecule oxygen, the 1x1x2 unit cell of CNT and large diameter show a remarkable and stable compared to in 1x1x1 unit cell and small diameter of CNT. Thus, the adsorption energy of the oxygen molecule shows a more stable value in the low doping ratio and high CNT diameter compared to a high doping ratio and a small diameter of the CNT. This result shows the potential of the CNT in helping to improve electrochemical reaction in DLFC.

Keywords: Surface reaction; CNT; electrochemical reaction; oxygen adsorption

The halal status of the vaccine is being questionable among the Muslim community around the world. Some of them even took a risk not to take the vaccine when this issue is resurrected. This is due to the uses of porcine trypsin that comes from the prohibited animals which is pancreas (pig). The main aim of this study is to find the effectiveness of alternative enzyme (Acutase™) that comes from invertebrate sources in replacing the trypsin™ enzyme. Two modes of operation which are batch and continuous mode were compared to determine the high production rate of the vaccines. The production of syariah-compliant vaccine mainly focused on the bioreactor and simulated by using a software called SuperPro® Designer. The different reactions of time ranging from 1-5 days were tested to each enzyme. The hemagglutinin (HA) concentration gained will form the growth curves of the cell. The HA concentration data from the simulation indicates the number of cell growth in the cell culture process. Result shows a batch reactor can achieve until 60% of the yield production. The curves show the highest concentration of cell by using Acutase™ is at day 3 which is 1.17 X 106 cells/mL. Meanwhile, 0.98 x 106 cells/mL produced by trypsin enzyme at day 4. Total hemagglutinin produced is calculated by using the following standard condition, 1 HA unit corresponds to 104 cells per mL. Therefore, the hemagglutinin (HA) concentration produced by using acutase™ is 117 Unit HA compared to the trypsin™ which is 98.8 Unit HA. The results prove that the production of syariah compliant influenza vaccine can be produced in the future and enhance the uses of the vaccine among Muslim community.

Keywords: Batch Reactor; Influenza Vaccine Syariah Compliance; Acutase™; Trypsin™; SuperPro® Designer

Bifacial solar cell has symmetrical configuration contacts on front and rear surface that eliminate expansion mismatch, decrease metal usage and improves photon absorption. The limitation of the reflector at the back of bifacial solar panel able to be eliminated by developing special designed partially transparent bifacial solar cell to optimize light trapping on rear surface. Therefore, the partial transparent silicon (Si) wafers were developed to increase light transmission to rear surface. Surface modification on Si wafer was conducted to form partial transparent Si wafer. Surface modification was employed by pulsed laser interaction to create dot marking array on Si wafer. Two pulsed laser power applied were 25.5W and 39.6W to produce pattern, then immersed in 10% KOH solution to etch laser-induced structure and debris to form partial transparent Si wafer. Low power laser was induced 80-85 μm depth of micro-hole, while high power was induced 140-145 μm. KOH treatment was conducted to etch laser region which to form deeper and wide micro-holes. The bifacial solar cells have been fabricated using partial transparent Si wafer and the current-voltage of the devices were tested. The front surface efficiency obtained for both partial transparent bifacial solar cells were 4.36% and 5.59%, while rear surface achieved 1.23% and 1.16%. Fabricated conventional bifacial solar cell has an efficiency of 2.39% for front and 0.64% for rear. The surface modification enhanced the efficiency due to the photon path length transmission to rear surfaces, micro-hole’s dimension and optical absorption in the near-infrared region.

Keywords: Bifacial solar cell; Surface modification; Pulsed laser; Efficiency; Partial transparent

This research presents a development of the affine projection algorithm (APA) in voice communication applications. A method of controlling the parameters of the APA is devised to improve the performance in cancelling various types of ambient noise that could possibly corrupt speech signals in voice communication systems. Indicators are used to identify the type of noise accompanying the target signal. Then the corrupted signal is processed in a noise a cancellation setup in such a way that three parameters of algorithm are changed according to the nature of the noise. The spreading of elements in the covariance matrix of the noise is used as an indicator for the type of noise so that the projection order, step-size and filter length are changed at the same time. This way the performance of the canceller is improved rendering lower estimation error with a moderate computational power. The method was tested under various types of noise and showed better convergence performance than the original APA as well as other commonly used algorithms in noise cancellation systems. The MSE of the proposed VPAPA method drops to -65 dB in steady state compared to -20 dB using NLMS and just below -30 dB using standard APA with projection order of 8, while the powerful RLS reaches around -60dB under the same environment. The method can be useful for clearer voice communication in variable environmental noise.

Keywords: Adaptive filtering; noise cancellation; affine projection; speech enhancement

Graphene is one of the best reinforcement materials but have a strong tendency to agglomerate and will affect the final properties of the composite. Effect of mechanical properties with addition of Graphene Nano-platelets (GNPs) in copper through powder injection molding (PIM) process was investigated. 2 feedstocks was prepared, one is Cu 100% and Cu/0.5 vol.% GNPs. Both feedstocks use same powder loading, 62% powder and 38% binder and the binder system used for this study consist of polyethylene glycol (PEG), polymethyl methacrylate (PMMA) and stearic acid (SA). The feedstocks were sonicated, and ball milled using the same parameters and then continue with until injection process. The produced green part strength and density were tested. The main reason to for density testing is to determine either addition of GNPs will affect the composite density The average green density for Cu 100% is 5.835 g/cm3, which is 99.84 % from the theoretical density. Meanwhile for Cu/GNps 0.5%, the average density is 5.874 g/cm3, which is 99.91 % from the theoretical density. For the green strength, the average maximum flexural strength for Cu 100% is 15.29 MPa and 14.32 MPa for Cu/0.5 vol.% GNPs. Even though the density of Cu/GNPs composites decrease with addition of 0.5 vol% GNPs but both sample strength indicates good mechanical properties and suitable for debinding and sintering process.

Keywords: Copper, Graphene, powder injection molding, flexural strength

Powder injection moulding (PIM) is a process that combines the technologies of plastic injection moulding and powder metallurgy. The fabrication of titanium alloy-hydroxyapatite (Ti6Al4V/HA) composite using PIM is still poorly reported due to the difficulties in processing two different materials namely the metal and ceramic. Such promising composite can be proposed as an implant material due to its great properties. Hence, this work aims to characterise the properties of Ti6Al4V/HA composite produced by PIM. In this work, 90 wt% of Ti6Al4V and 10 wt% of HA were mixed with a binder system of 60 wt% palm stearin and 40 wt% polyethylene. The powder loading of the feedstock was 66 vol%. The feedstock with a pseudoplastic flow is preferred in PIM as fewer defects are formed during the injection moulding process. Moreover, the binders are removed in two stages namely the solvent and thermal debinding. Based on the observation, the removal of palm stearin created capillary routes that help to remove polyethylene during thermal debinding. Next, sintering was performed at three different temperatures, which include 1100oC, 1200oC and 1300oC. The heating rate, holding time and cooling rate was set at 3oC/min, 90 min and 6oC/min, respectively. It was found that Ti6Al4V/HA sintered at 1300oC yielded the highest density of 4.13 g/cm3. In addition, such sintered part also generated the highest flexural and Young’s modulus with the values of 86.4 MPa and 15.04 GPa, respectively. These values are approximately in the range of the physical and mechanical properties of the extant bone-implant.

Keywords: Powder injection molding; Ti6Al4V/HA composite, Rheological properties, Physical and mechanical properties