bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Solid Catalyst from Palm Empty Fruit Bunch for Production of Biodiesel through Esterification
Authors: Kam Huei Wong , Lim Steven , Yean Ling Pang , Chin Yi Yap
Published: July 2019

Application of solid acid catalyst in biodiesel production gains much attention from researchers as it is suitable for most of the non-edible and low value oils which will significantly cut down the total production cost and reduce corrosion issue. In this research, biomass from palm empty fruit bunch is used as the carbon precursor to synthesis activated carbon (AC) before sulfonated by 4-benzenediazonium sulfonate (4-BDS) to produce solid acid catalyst. The synthesized catalysts were characterized and the performances were tested in esterification of palm fatty acid distillate (PFAD) to produce biodiesel. Scanning Electron Microscope (SEM) showed that a clear porous and rough surface was developed after calcination at relative low temperature (200 ° C) which favors the attachment of the acid active site. It also found that that the total acid sites of the catalyst increased when sulfanilic acid loading increased during sulfonation. In catalytic activity test, the result showed that catalyst calcined at 200 ° C and catalyst sulfonated with 15:1 sulfanilic acid to AC ratio was the optimum catalyst as they gave the highest biodiesel yield at 73.14%.
Thermal Insulation Properties of Organic and Inorganic Material in Clay Brick - A Review
Authors: Nazira Ab. Karim Nur Fatin , Nabilah Sarbini Noor , Abdul Shukor Lim Nor Hasanah , Syahrizal Ibrahim Izni , Aminuddin Eeydzah , Rosseira Abu Talib Adrina
Published: July 2019

Pore forming agent is widely used in clay brick making process whether originally organics or inorganics materials which can improve thermal insulation facing global warming issue. Many researchers trigged to discover the thermal insulation materials since the past decade due to responsibility to develop a comfort living demand for heating or cooling. This paper review on different types of thermal inorganic and organic insulation materials added into a clay brick to improve the thermal insulation properties. The scope of these reviews lies to the materials of; paper residue, rice husk, rice husk ash, olive stone flour, wheat straw, perlite, cigarette butt, vermiculite, waste marble powder and waste glass sludge. The discussions are made based on the properties of organic and inorganic materials used in improving the thermal insulation in clay brick. Hence, a throughout review of the composition and properties of brick and various factor related to manufacturing process is highly required for better standardization of clay bricks. A better understanding of different wastes incorporating clay brick utilize of various mining and industrial as well as achieving the goal of sustainable development.
Multi-objective Design of a Biomass-based Polygeneration for Iron and Steel Manufacturing
Authors: Ubando A T , Chen W H
Published: July 2019

Iron and steel manufacturing is considered a major contributor to the global carbon emission and energy-intensive industry. To sustainably produce iron and steel, various approaches have been explored to generate the needed power to support the production while mitigating the carbon dioxide emission. One of the viable approaches is the integration of a biomass-polygeneration system to produce biochar and other energy streams needed by the iron and steel manufacturing plant. A polygeneration system is composed of a combination of various existing technologies which seeks to recover wasted energy and to reuse by-products through process integration, thus, improving the overall thermodynamic efficiency of the system. In designing such complex systems, multiple objectives should be considered to assimilate the real-life requirements of the system. However, recent studies on the design of polygeneration system for iron and steel industry used a single-objective approached which may not consider the trade-offs between multi-objectives. Hence, this study proposes to design a biomass-based polygeneration system using a multi-objective approach employing fuzzy linear programming (FLP) model. The FLP model allows partial satisfaction of multi-objectives through the use of linear membership functions. A case study is presented involving biochar production from torrefaction, pyrolysis, and gasification together with power and heat production. The results indicate the optimal polygeneration process network consisting of a gas turbine for the generation of power, a heat recovery steam generator attached to the gas turbine for the heat generation, a gasifier for syngas, and torrefaction for biochar production. The developed model aims to aid engineers and managers in cost-effectively integrating a biomass-based polygeneration system in iron manufacturing.
Study of transient conjugate heat transfer in helical closed-loop geothermal heat exchangers for application of thermal energy storage in backfilled mine stopes
Authors: Templeton JD , Ghoreishi-Madiseh SA , Hassani FP , Sasmito AP , Kurnia JC
Published: July 2019

The geothermal potential available from deep underground mines has yet to be utilized. However, stope coupled heat exchangers (SCHE) are aiming to take advantage of the unused low-grade geothermal energy. Backfilled stopes provide a unique opportunity to install non-linear heat exchangers, as the geometry is not limited to the shape of a borehole. Helical pipes deliver superior fluid mixing and heat exchange compared to straight pipes, due to the effect of the secondary flow within the helical pipe. The helical closed-loop geothermal heat exchanger enables the backfilled stopes of the mine to be repurposed as thermal energy storage units. This paper delves into the experimental results from a laboratory scale helical closed-loop heat exchanger with varying thermo-physical parameters. Additionally, a conjugate numerical model is developed and its results are validated against the base case of the experimental studies. The results of the numerical model suggest that the pumping rate through the SCHE has a significant effect on the heat exchange rate and the overall energy transfer between the SCHE and the backfill.
Energy and Exergy Analysis of Steam Power Plant in Paiton, Indonesia
Authors: Rudiyanto Bayu , Kusuma Wardani Tri Ajeng , Anwar Saiful , Al Jamali Lutfi , Prasetyo Totok , Mukti Wibowo Kukuh , Agung Pambudi Nugroho , Huat Saw Lip
Published: July 2019

The exergy analysis of steam power plant system in PT. Jawa Power-YTL, East Java unit 5 was performed based on the first and second law of thermodynamics. Exergy flow and exergy efficiency were calculated for each component of the plant i.e. the boiler, HTP, IPT, LPT, deaerator, condenser, HPH, LPH, CEP and FWP. The exergy steam-flow of 970288 kW produced 610.000 kW of electricity with an exergy efficiency of 26.36%. Sankey diagram showed the exergy loss on each component of the steam power plant. The irreversibility of the boiler, condenser, turbine, LPH, HPH, pump and daerator were 1677003 kW (17,28 %), 738122 kW (7,61 %), 152894 kW (1,58 %), 111881 kW (1,15 %), 470520 kW (4,85 %), 193494 kW (1,99 %) and 1081771 kW (11,15 %), respectively. The total exergy that could be converted into electrical energy in the system was 5276259 kW (54,39%). The highest irreversibility was in the boiler with 1677003 kW (17,28%). The optimization result showed that the highest efficiency was 94.04% at an output pressure of 41 bar.
Possibility of Using Stirling Engine as Waste Heat Recovery – Preliminary Concept
Authors: Saadon S.
Published: July 2019

Growing consumption of primary fossil fuels and massive discharge of pollutants are some of the results caused by the world’s growing population, and eventually the enlarging energy demand. It is therefore the main concerns that the developing world must face nowadays are the energy shortfall and the environmental destruction. And for these valid reasons the awareness of reusing the low-grade heat has captivated researchers in recent years. Due to its unique features, Stirling engines, is a powerful candidate to recover the waste heat by converting it into power. However, Stirling engine shows a drastic performance penalization if connected with lower temperature heat sources and therefore research has to be done to increase the performance of the heat transfer in the Stirling engine. Exhaustive research has been done by many investigators to enhance the heat transfer characteristics inside the tube heat exchangers. However, the areas related to outer tube geometries with different materials and different fins attachment have not yet been explored and this part is the important factor for an external combustion engine to enhance the heat transfer. Thus, the development of Stirling engine as waste heat recovery needs to focus on identification of heat transfer enhancement methods that can be applied at the outer part of tubular heater in order to achieve an optimum performance of the engine. Starting from a comprehensive review of Stirling engine, this paper presented a rigorous derivation of a novel waste heat recovery system using Stirling engine with large power that can benefit the environment and in line with national GTMP. Such result will be very useful in the preliminary design of a waste heat recovery system using Stirling engine and can be used in the estimation of power output for many applications.
Winterization of biodiesel through progressive freezing for cold flow properties improvement
Authors: Yee Min Hoo , Aini Amran Nurul , Samsuri Shafirah
Published: July 2019

In cold environment, pure biodiesel cannot be used directly as an alternative fuel as it crystalizes easily at low temperature due to its saturated fatty acid (SFA) content. Thus, the winterization method is used to reduce the SFA content that gives high melting point to biodiesel. However, the conventional winterization method was reported to be complicated and ineffective in separating the liquid and solid content formed. Progressive freezing (PF) is introduced to improve the separation efficiency in the winterization process by removing the solid SFA layer formed on the wall of the crystallizer without the use of complicated equipment. In this study, the initial value of cloud point (CP) and pour point (PP) of the biodiesel were measured and compared with the values obtained after the PF process. The effect of coolant temperature, freezing time and stirring rate towards the efficiency of the PF process were also determined. The obtained results showed that the best performance of winterization was observed at coolant temperature of 6 °C, freezing time of 20 minutes and stirring rate of 50 rpm. At this condition, the recovery of biodiesel is 65.46% while CP, PP and SFA content were reduced by 2.65 %, 14.29 % and 3.96%, respectively.
Power Output Prediction for LM Wind Turbine Blade using Blade Element Momentum Theory and GH Bladed Software
Authors: Augusto G , Culaba A , Chen W
Published: July 2019

The blade element momentum theory with Prandtl’s tip loss and Glauert’s correction factors was utilized to compute the power coefficient and to predict the power output of LM rotor blade as a function of hub wind speed ranging from 3 m/s to 25 m/s. The blade length is 43.8 m and consists of five (5) different airfoils. The design tip speed ratio is 8.65 suitable for Class IIA wind turbine which can generate a capacity of 2.5 MW at rated speed of 16 rpm using permanent magnet direct-drive wind turbine generator. The thrust force and driving force profiles in terms of dimensionless blade length as well as the power coefficient and predicted power output were examined and compared with the theoretical equations derived from GH Bladed. Numerical results indicate that there are some degrees of similarities with GH Bladed software output having a maximum power coefficient of 0.49.
Integration of Maceration and Freeze Concentration for Recovery of Vitamin C from Orange Peel Waste
Authors: Abdurrahman Isa Abdulmajeed , Samsuri Shafirah , Aini Amran Nurul
Published: July 2019

Vitamin C (L-ascorbic acid) is found in orange which provides health benefits to a human body. Orange peel is considered as a waste and dumping the peel can be avoided by extracting it to get valuable compound such as vitamin C. However, none of the vitamin C presents in orange peel has been utilized. Thus, integration of maceration and progressive freeze concentration (PFC) for recovery of vitamin C from orange peel was studied. Maceration is a conventional extraction technique that mostly used for obtaining compound extracts from plant and PFC is currently become attention for concentration process. For this purpose, different operating conditions for maceration and PFC were evaluated with regard to vitamin C recovery. The operating conditions that were analysed are drying temperature (30 to 45 °C), coolant temperature (-10 to -16 °C), cooling time (20 to 35 minutes) and stirring rate (200 to 800 rpm). Titration was done to analyse and correlate the increase of vitamin C in a concentrated solution for different operating conditions. Highest recovery was found at 35 °C of drying temperature, -12 °C of coolant temperature, 20 minutes of cooling time and 400 rpm of stirring rate. The highest value of recovery was found to be 72.06 %. Integrating both maceration and PFC methods add value to the orange peel waste and provide solution for environmental problems.
Numerical modelling of the power pack system for remote islands electrification
Authors: Saw LH , Cheow JS , King YJ , Yeo WH , Lim BH , Tey JY , Ng TC
Published: July 2019

Electricity is one of the indispensable elements in the daily life. From domestic to commercial sector, electricity has been used to provide a wide range of applications. However, access to electricity is only limited to the urban area while rural area electrification is always a challenge due to the geographical location and high cost of the electrification infrastructure. Therefore, electrification using solar energy is projected to be one of the feasible solutions in the rural area. A typical power pack system used for the rural area electrification consists of solar panels, voltage converters and battery pack. Although lead acid battery provides an economic solution for the energy storage system, they are also associated with other disadvantages such as low depth of discharge, bulky and low energy density. Li-ion battery is a new generation of battery technology with high energy density, light weight and high depth of discharge which offer a promising solution for an off grid power systems. In this study, an off grid power pack consists of Li-ion batteries, voltage converters and photovoltaic modules are modelled to evaluate the electrical performances of the system under Malaysia weather conditions. Then, the numerical modelling results are compared with experiments. It is found out that the numerical model correlated well with the experimental data with a relative error less than 5%.
Performance analysis of low GWP refrigerants mixture as a substitute for R410A in residential air conditioner in tropical region
Authors: Ng WenBin , Mohamed Kamar Haslinda , Kamsah Nazri , Wang Fu-Jen
Published: July 2019

The issue of global warming has triggered more critical issues, and today’s refrigerants with high global warming potential (GWP) are facing the challenges of being phased out. According to 2014 Assessment Report of the Refrigeration, Air-Conditioning and Heat Pumps Technical Options Committee (RTOC Assessment Report 2014), the R410A has GWP of 2100 and is widely used in residential air-conditioning and heat pump systems. Currently, in the market, the potential refrigerant that can be used to replace R410A in the air-conditioning system is R32. The purpose of this project is to create a new refrigerant mixture using low GWP refrigerant as a base that can replace for R410A in an air-cooled split air conditioner. Simulation works have been developed using Refprop software to simulate the refrigeration cycle with the operating conditions of the air-cooled split air conditioner, in the tropical region. The chosen cycle was an ideal vapour compression cycle with the evaporating and condensing temperatures of 5 °C and 47 °C, respectively. Through this study, two potential refrigerants mixture was found to be suitable to replace the R410A. The two refrigerant mixtures, R32/R1234ze and R32/R600a, both based on R32, were found to have similar thermodynamic properties as the R410A. They were found to be able to produce the coefficient of performance (COP) very close to the R410A when used in an air-cooled split air-conditioning system. Hence, the use of this refrigerants will avoid significant modifications on the present air-conditioning system configurations. Refrigerant R32/R1234ze has the potential to reduce the GWP of R410A by 70 % while refrigerant R32/R600a by 73 %. At the end of the equipment lifespan, refrigerant R32/R1234ze would reduce the direct of Total Equivalent Warming Impact (TEWI) by 23 % while refrigerant R32/R600a by 20 %.in constructing both.
Synthesis of biodiesel from Schizochytrium oil using renewable catalyst and study of its quaternary blend phase behaviour
Authors: Kowthaman C N , Selvan V Arul Mozhi
Published: July 2019

In this present work, waste animal bone is used for the first time to synthesis nano hydroxyapatite heterogeneous catalyst. The sodium nitrate salt was doped with synthesized nano hydroxyapatite to form sodium modified nano hydroxyapatite for transesterification of biodiesel from schizochytrium algae oil. Locally collected waste bone was washed, cleaned, dried, powdered and calcined at different temperature at 900 °C for 2 h to convert into tri-calcium phosphate and it is characterized. The synthesized heterogeneous catalyst was tested for biodiesel production. The maximum biodiesel yield of 96% was achieved at 9 wt.% catalyst concentration, 1:12 molar ratio and 2 h reaction time. The produced biodiesel was characterized to evaluate the quality for the application in diesel engines and the results exhibited that the properties are in ASTM standard limit. Blending of biodiesel, lower alcohol with diesel have been considered as the common fuel modification for reducing the pollution. In this study, the phase behaviour of the synthesized Schizochytrium biodiesel, diesel and higher alcohol (Octanol) was studied with water in oil emulsions (Quaternary blend). Octanol was used because of its high carbon number and better fuel property. The effects of different hydrophilic lipophilic balance were studied to find an optimum HLB number by varying the Span 80 and Tween 80 ratio (20 to 100%) in the quaternary blend. The optimum fuel blend was found at the HLB number of 12 (Span 20%: Tween 80%) and the quaternary blend at the HLB 12 showed no phase separation for two months.
The Effectiveness of Various Bimetallic on Iron-Zeolite Catalyst by Carbon Dioxide Hydrogenation
Authors: Amat Bahari Nurazni , Roslam Wan Isahak Wan Nor , M. Ba-Abbad Muneer
Published: July 2019

Nowadays, the concentration of carbon dioxide (CO2) getting worse and increasing year by year due to the open burning, transportation, deforestation, use of synthetic fertilizer and industrial process. The concentration of CO2 has reached 406.99ppm since August 2018. This can cause global warming, rising sea level, climate change and etc. Therefore, an intensive research was done to control this issues on hydrogenation of CO2 reaction by using composite catalyst. A series of X/Fe-Zeolite (X=Co, Cu, Pd and Ni) were synthesized by sol-gel method that using oxalic acid and precursors of nitrate. The Fe-Zeolite act as both a support and a co-catalyst while bi-metal served as promoter for CO2 hydrogenation. Parameters that involved for synthesized the composite which are fixed weight ratio of X:Fe:Zeolite (0.1:1.25:2), the polyethylene glycol (PEG) of 2 mL and calcine temperature of 500°C. Then, the composite was evaluated on CO2 hydrogenation at temperature reaction of 130°C, pressure CO2:H2 of 1:3.5 bar, weight catalyst of 0.2g and time reaction of 6 hours in liquid 1,4-dioxane solvent. Formic acid (FA) was the major product in this research. The effectiveness of composite was studied after addition of bi-metal onto the surface area Fe-Zeolite can boosted the production of FA or not. Transmission Electron Microscopy (TEM) determined the morphological and textural properties of the synthesized catalysts and X-Ray Diffractometer (XRD) while the formation of FA from CO2 hydrogenation reaction was evaluated using High Performance Liquid Chromatography (HPLC). By this way it can reduced the concentration of CO2 at atmosphere and getting value-added product from the reaction.
Numerical Validation of a Pressurized Batch Reactor for In-Situ Transesterification
Authors: Chiu G M , Culaba A , Ubando A , Madrazo C
Published: July 2019

Subcritical in-situ transesterification is one of the more recently developed processes that consumes less energy and is more environmental friendly than conventional methods. Diving deeper into this process, the fluid dynamics of the liquid mixture is an area of interest not studied before due to the solid, thick metal enclosure of the reactor vessel. Previous studies observed that the mixing characteristics of the agitator being used influences biodiesel yield. As commercialization of this biofuel production process is of importance in order to contribute to biofuel demand in a nation-wide scale, this study considers a reactor vessel working volume of around 1.5L, which is relatively larger than typical laboratory batch-type sizes. A numerical validation study, through mesh analyses, was performed to produce a numerically accurate model for the study. Factoring in computational time and accuracy of the solution, a steady state, multiphase model running the standard k-∈ turbulence model was chosen. The Multiple Reference Frames approach was used for the steady state condition to be met. The validation model is of a 6.3L-volume cylinder with baffles. Glass beads served as the solids and water as the liquid in the system. The first mesh analysis was performed by comparing 11 unique mesh models. The model with a relevance of fine 30 was seen to have the closest data fit with the experimental data. It was seen that only when using the size function ‘proximity’ showed a slightly different velocity profile among the models. The second mesh analysis was conducted to check if the chosen mesh setting would affect this study’s smaller reactor geometry before the main study’s simulations are to be conducted. The model with baffle’s percent error at the specified point was at an acceptable 8.2%, and its resultant velocity profile’s is at 23.5% which is around the same range as that of the 1st mesh analysis’ models. With this, the numerical model developed was deemed to be applicable for the main study.
Reduced graphene oxide on the performance of solid-state dye-sensitized solar cell
Authors: Foong HH , Ahmad H , Ting CH , Ng CY , Jun HK
Published: July 2019

Dye-sensitized solar cell (DSSC) is a third generation solar cell which provides a good research platform for future photovoltaic technologies. DSSC can be categorized into two types based on the nature of its electrolyte, namely liquid and solid-state. In general, DSSC with liquid-based electrolyte has risk of electrolyte leakage. Therefore, the utilization of solid-state hole transport materials instead of liquid electrolytes can overcome the leakage issue of liquid-based DSSC. Despite of this advantage, the performance of solid-state dye-sensitized solar cell (SS-DSSC) is low compared to the cell that uses liquid electrolyte. To remedy this, doping with foreign materials is used to enhance the performance of the solar cell. Hence, this work focuses on the effect of reduced graphene oxide (RGO) on the performance of SS-DSSC utilizing TiO2 nanoparticles. The electrode samples were characterized with scanning electrode microscopy, energy dispersive spectroscopy, UV-Visible spectroscopy, IV test, and electrochemical impedance spectroscopy (EIS). By introducing RGO into SS-DSSC, the efficiency and fill factor was improved by at least 15%. Moreover, the presence of RGO increased the electron lifetime with higher recombination resistance as observed from EIS result.
Development of Bioflocculant from Chicken’s Eggshell Membrane to Harvest Chlorella vulgaris
Authors: Suparmaniam U , Lam MK , Uemura Y , Shuit SH
Published: July 2019

As microalgae biomass is considered as the most assuring source of biodiesel, flocculation has become a potential technology that could be able to alleviate microalgae dewatering cost which is the cornerstone hindrance of their full-scale application. However, large scale harvesting of microalgae biomass using commercial flocculating agents is obstructed by economic and environmental drawbacks upon downstream discharge. Thus, in the present work, a novel introduction of natural flocculant extracted from waste biomass, which is, chicken’s eggshell membrane was made to harvestChlorella vulgaris. Flocculation tests were carried out to test the effectiveness of the natural flocculant to recover microalgae biomass. Chicken’s eggshell membrane was proven to be one of the effective bioflocculant as it achieved above 60 % of flocculation efficiency after 1 hour of sedimentation with optimum flocculation parameters of pH 11.8 with 80 mg/L of flocculant dosage at 40 °C.
Evaluation of political risk factors influencing energy supply disruption
Authors: Soliman J , Lopez N S , Biona J B M
Published: July 2019

High dependence on imported energy supply makes a country vulnerable to risks of supply disruption. Disruptions can be in the form of government policies, external conflicts, and natural calamities. Several indicators quantifying the probability of supply disruption were proposed in past studies based on a defined set of criteria. However, factors influencing the behavior of energy exports vary per country. In this study, 12 political risk components were investigated and correlated with historical oil-export data to assess the main drivers dictating export behavior. A case study was conducted on Philippine crude oil suppliers from 2001 to 2015, and three countries were elaborated for further discussion. Results showed that oil exports are strongly correlated with internal and external conflicts in Saudi Arabia; internal conflicts in Venezuela; and socioeconomic conditions in Russian Federation. The study recommends utilizing the developed methodology to aid estimation of energy security costs based on various political risk scenarios.
Renewable energy-based artificial ground freezing as an adaptation solution for sustainability of permafrost in post-climate change conditions
Authors: Alzoubi Mahmoud , Ali Ghoreishi-Madiseh Seyed , Sasmito Agus P. , Kunz Nadja , Guimaraes Alice
Published: July 2019

Climate change is expected to impose higher ground temperatures, seriously challenging the sustainability of permafrost regions by thawing irreversibly, compromising ground stability and causing high seepage flows. Mining operations are particularly vulnerable to permafrost removal, and in extreme cases may face catastrophic consequences in their waste management systems, such as tailings dams. So far, artificial ground freezing has been promoted as a reliable and technologically possible solution to maintain permafrost against raises in ground temperature. However, considerable amounts of electric power are required which can be challenging especially in remote areas. A solution can be sought by taking advantage of cold winter temperatures to provide artificial ground freezing. In this renewable energy-based technique, thermosyphons use subfreezing winter temperatures to create enough freezing in the permafrost layer which can last during the summer as well. The present paper underlines the importance of developing the proposed technology and evaluates its techno-economic feasibility through numerical and experimental studies. It offers a numerical model for a renewable energy-based artificial ground freezing system and validates its results against laboratory experiments. The results suggest that the utilization of thermosyphon along with cold-energy storage increases and maintains the thickness of the permafrost, especially during the summer season.
Development of a hybrid coir fiber composites as ballistic material
Authors: Mawardi I , Zubir M N M , Bakri J , Jannifar A , Hanif
Published: July 2019

Utilization of composite material in military application can provide better performance compared to metal material especially in increasing the mobility capacity of defense personnel. The objective of this research is to develop ballistic material from composite hybrid with coir and synthetic fibers as its reinforcement. Composite hybrid is formed using epoxy matrix with (Coir + Alumina)-E-glass-Fabric-Rubber. The coir used is in short fibers form after fibrillation process. Alumina is used for 5% of resin weight. The specimen is formed with hand lay-up method. The test of mechanical and physical properties is conducted to observe the reinforcement mechanically and physically. The firing test is aimed to find out the ballistic durability. The result of mechanical characteristic test shows that composite hybrid has tensile strength 76 Mpa, 58,02 kJ/m2 for impact strength and 0,00122 g/mm3 for density. The result of ballistic test shows that composite hybrid material is able to detent the bullet in level IIA.
Influence of layer numbers on the structural and electrical performance of cobalt-free SrFe0.5Ti0.5O3-δ cathode for ntermediate-temperature solid oxide fuel cell application
Authors: Baharuddin N A , Wan Yusoff W N A , Muchtar A , Somalu M R , Abdul Samat A , Anwar M
Published: July 2019

The influence of layer numbers on the structural and electrical performance of SrFe0.5Ti0.5O3-δ cobalt-free cathode was studied. The SrFe0.5Ti0.5O3-δ cathode films fabricated using screen-printing technique with different layer numbers sintered at 1300 °C for 2 h were characterised using field-emission scanning electron microscopy (FESEM) for structural analysis and four-point van der Pauw method for direct current electrical conductivity (σDC). FESEM micrographs confirmed that the SrFe0.5Ti0.5O3-δ cobalt-free cathode films (fabricated with different layer numbers) adhered well on the samarium doped ceria electrolyte surface. The porous films were also uniform without crack formation. The thicknesses of the as-fabricated cathode films were 9.0 ± 0.5, 25.6 ± 1.0, 54 ± 0.6, 71.2 ± 1.4 and 92.2 ± 1.6 μm for layer numbers 1 (1×), 4, 7, 10 and 13 times (13×), respectively. The electrical performance of SrFe0.5Ti0.5O3-δ cobalt-free cathodes was reported within the operating temperature ranging from 550 °C to 800 °C as the targeted application was the intermediate temperature solid oxide fuel cell. The layer numbers (thickness) dependence of σDC suggested a mechanism of long electron pathway at the surface and through the films due to the increase in pores. While the sintering temperature is kept constant, increasing in the number of layers increased the pores accordingly. Hence, the lowest σDC value at 800 °C (2.45 S cm−1) is obtained for SrFe0.5Ti0.5O3-δ cathode films with high number of layers (13×). The highest σDC value (16.46 S cm−1) was recorded for a single layer (1×) SrFe0.5Ti0.5O3-δ cathode film. Although the conductivity value was still far from the desired theoretical conductivity of 100 S cm−1, this result was better than that of the literature that reported the same composition, thereby showing that the quality of cathode film was improved.
First Principles Investigation on H2 Adsorption on the Pristine 2-Dimensional Hexagonal Aluminum
Authors: Villagracia A R , Ong H L , David M , Arboleda N
Published: July 2019

Lightweight hydrogen storage with high storage capacity is one of the challenges in pursuing a hydrogen economy as a source of clean energy. Aluminum has been proposed as a material for storage and production of hydrogen. Recent theoretical studies have established the feasibility of 2D hexagonal lattice structure aluminum. In this study theoretical investigation on 2D h-aluminum was performed employing density functional theory to study the energetics of hydrogen molecule and 2D h-aluminum system. Hydrogen molecule on top, hollow and bridge sites of hexagonal lattice were geometrically optimized to determine if hydrogen molecule would dissociate or adsorbed as a molecule. Results showed that hydrogen molecule can be physisorped mainly in the bridge site (-0.463 eV) at a distance of 3.1 Å, while it can dissociate at the top site with an activation energy of 1.51 eV. Electron density difference shows transfer of 0.60e− from hydrogen atoms to the aluminum atoms. Density of states showed broadening of energy levels and their general shift towards lower energies, and alignment of the orbitals showing sp hybridization. Results of this study can be used in further investigation on doped or decorated systems of 2D h-aluminum.
Optimisation of screen-printed La0.6Sr0.4CoO3-δ cathode film for intermediate temperature proton-conducting solid oxide fuel cell application
Authors: Abdul Samat Abdullah , Rao Somalu Mahendra , Muchtar Andanastuti , Akidah Baharuddin Nurul , Osman Nafisah
Published: July 2019

The effect of thin film properties on the electrochemical performance of La0.6Sr0.4CoO3-δ (LSC) cathode was investigated. A single phase of sol-gel derived LSC cathode powder is produced using ethylene glycol (EG) and activated carbon (AC), pressed into a pellet and turned into an LSC cathode slurry. The slurry is screen printed with different printing numbers (2, 4, 6 and 8 times) on the BaCe0.54Zr0.36Y0.1O3 (BCZY) electrolyte substrate to fabricate LSC|BCZY|LSC symmetrical cell. The EG-based LSC cathode recorded the lowest area specific resistance (ASR) value (0.11 Ω cm2) in the symmetrical cell fabricated with printing number of 2 times (film thickness = 3.90 ± 0.18 μm, film porosity = 23.09 ± 0.42 %). The AC-based LSC cathode requires a high printing number of 6 times (film thickness = 6.76 ± 0.50 μm, film porosity = 21.98 ± 0.52 %) to obtain the lowest ASR value (0.15 Ω cm2) because the electrical conductivity of the AC-based LSC cathode is lower than that of the EG-based LSC cathode. Overall, this work shows that the variations in the ASR values of the same LSC materials prepared with different chemical additives are affected by the properties of the printed thin film.
Performance of LiCo0.6Zn0.4O2 as a potential cathode material candidate for intermediate solid oxide fuel cell application
Authors: Anasuhah Wan Yusoff Wan Nor , Wardah Norman Nur , Abdul Samat Abdullah , Rao Somalu Mahendra , Muchtar Andanastuti , Akidah Baharuddin Nurul
Published: July 2019

Li-based materials, previously used in lithium batteries, are now actively applied in solid-oxide fuel cells (SOFCs). The synthesis and characterisation of LiCo0.6Zn0.4O2 (LCZO) cathode powder calcined at 600 °C for SOFC application has been reported. In the present work, LCZO powder was calcined at 700 °C and its properties were investigated. Results showed that the impure phases recorded through X-ray diffraction (XRD) in a previous work decreased with the ZnO phase at approximately 37.4%, and 62.6% of LCZO remained. Transmission electron microscopy was used to study the morphology of the calcined powder, wherein the crystallite size obtained from XRD well agreed with the XRD analysis result. The LCZO particle size calcined at 700 °C was examined with a particle-size analyser. The electrical conductivity of bulk pellet was tested at 400–700 °C, and the highest conductivity of 9.90 Scm−1 was recorded at 700 °C. Overall, this material exhibited excellent potential for proton-conducting SOFCs application.
Tailored Optical and Mechanical Properties of Nanocellulose Composites: From Green Natural Fibers to Strong Hybrid Reinforcements
Authors: Lin Y S , Kuo P Y
Published: July 2019

Nanocellulose is an emerging green material possessing many advantages, including biodegradability, light weight, superior strength, high transparency, and low coefficient of thermal expansion. This novel nanostructure was selected as core material in the Japanese Revitalization Strategy. Nanocellulose is a family referring to many nanostructured celluloses with various size and aspect ratios, such as nanocellulose crystals (NCCs) and nanocellulose fibers (NCFs). NCCs are short, brittle, and highly transparent, while NCFs are long, flexible, and superior ductile. Both are promising reinforcements, but the hybrid effect of NCCs and NCFs are rarely found in previous research. The purpose of this study is to tailor optical and mechanical properties of nanocellulose composites using various ratios of NCCs/NCFs, and then further observe any synergism between NCCs/NCFs. The experimental method was divided into four phases, including acid hydrolysis to prepare NCCs, tailoring the formula of composites (NCCs/NCFs/Epoxy), removing water by solvents, and then finally curing the composites by amine crosslinker. The results show the newly prepared composites have less density than glass, ten times more in tensile strength, and competitive transmittance in optical properties. Our future work will apply this newly developed composite in flexible electronic substrates, such as smart windows and solar panels.
The Effect of Diameter Downcomer in Air Entrainment Process from Vertical Plunging Water Jet with Downcomer
Authors: Warjito  , Budiarso  , Jaya Raka Loh
Published: July 2019

The development of technology for flotation in water-waste treatment is happening rapidly this environmentally friendly technology uses air bubbles to separate the material into hydrophilic or hydrophobic factions as a result of a bubble’s characteristics and additional chemicals. Air entrainment events occur when bubble formation takes place. At the time of bubble formation, air entrainment events occur. This study aims to determine the parameters that affect air entrainment; those are the relationship of the downcomer diameter and jet velocity to air entrainment from a fluid mechanics aspect. The apparatuses used in this study were a pump, nozzle, downcomer, flow meter, reducer, and glass water tank; these items were all connected with pipes. Data was collected via a camera to obtain photos and videos. Quantitative and qualitative data was derived from these images using an image processing program; ImageJ. The esults of this research indicate that the diameter of the downcomer affects the volume of the air entrainment, and jet velocity affects air entrainment rate.
Properties of Pr and In-doped BaZrCeY-based electrolyte for Proton Conducting Fuel Cell systems
Authors: Rashidah Rashid Nur Lina , Rao Somalu Mahendra , Muchtar Andanastuti , Roslam Wan Isahak Wan Nor
Published: July 2019

Proton conducting oxides are potential electrolyte candidates for intermediate-temperature solid oxide fuel cell (SOFC) because of their attractive advantages such as excellent ionic conductivity and moderate activation energy for proton transfer. At present, many investigated protons conducting oxides are BaCeO3 and BaZrO3-based materials. In this study, BaCeZrY-based electrolyte doped with Pr and In was synthesised by microwave-assisted glycine nitrate process. The synthesised powders showed a single cubic perovskite phase without any additional phases and thus have potential application in Proton Conducting Fuel Cell systems.
Investigation on water adsorption on 3-crosslinked circular polyacrylamide membrane using ab initio, molecular dynamics and monte carlo calculations for dewatering microalgae
Authors: Villagracia A R , David M , Arboleda N , Ong H L , Doong R , Culaba A , Chang J , Chen W
Published: July 2019

Microalgae has been identified as a source of biomass and biofuel which can be cultivated easily in large amounts given a small land area requirement. However, minimizing microalgae’s moisture content to 10% has been a bottleneck due to its energy intensive requirement and/or poor-quality outcome. A solution for this is the low-energy efficient forward osmosis system which needs a water superabsorbent polyacrylamide (PAM) hydrogels to maintain the salt concentration on the draw solution. Water sorption on 3-crosslinked circular polyacrylamide membrane was investigated using ab initio principles, molecular dynamics and monte carlo calculations. The PAM structure was geometrically optimized using density functional theory, and then equilibrated at room temperature and 1 atm pressure for 1 ns using molecular dynamics simulation. Monte Carlo simulations at room temperature with 2,500,000 steps and geometry optimization per step were performed to identify the adsorption sites for 25, 50, 75, 100, 125, and 150 water molecules by calculating their adsorption energies under the Dreiding Forcefield Model. A mathematical model was fitted to identify the relationship of adsorption energies with the number of water molecules that can be absorbed. Results showed this material can potentially adsorbed 1082 kg - 2345 kg of water per cubic meter of material when translated from calculated amount of water molecules that was adsorbed per unit cell volume. This study serves as a foundation for exploration of the new material circular polyacrylamide membrane that can facilitate microalgae drying to produce biomass and biofuel.
Development of Sr0.6Ba0.4Ce0.9Pr0.1O3-δ Electrolyte for Proton-Conducting Solid Oxide Fuel Cell Application
Authors: Norman N W , Wan Yusoff W N A , Jais A A , Somalu M R , Muchtar A
Published: July 2019

Sr0.6Ba0.4Ce0.9Pr0.1O3-δ is synthesized by the glycine–nitrate method. The synthesized powder and resultant electrolyte pellet are systematically characterised for proton-conducting solid oxide fuel cell application. The thermal decomposition and purity of the electrolyte powder were analysed by thermogravimetric analysis (TGA) and X-ray diffraction (XRD), respectively. The morphological structure and chemical stability of the electrolyte pellets are examined by field-emission scanning electron microscopy (FESEM) and XRD, respectively. The selective material decomposes at 1000 °C as recorded by TGA. The calcined powder at 1000 °C is used to produce the electrolyte pellet. The pellet sintered at 1400 °C achieves the average relative density of 94% as measured by Archimedes’ method and displays good grain growth with a visible grain boundary. The chemical stability of the pellet is also determined under boiling water for 2 h. The tolerance towards H2O for the sample improved with the presence of Sr upon exposure to boiling water even though some amorphous phase forms. Based on the result, Sr0.6Ba0.4Ce0.9Pr0.1O3-

δ
is considered as a potential electrolyte for proton-conducting solid oxide fuel cells.
Analysis of Performance on Ultra Wideband Circular Patch for Solar Cell Antenna Design
Authors: Hamidah A.Hamid Saidatul , Chin Hock Goh , Ferdous Nayla , Rahman M. Nazri A.
Published: July 2019

In this paper, a design of Ultra Wide-Band microstrip antenna based on circular microstrip patch for solar cell is proposed. In solar antenna design, researchers used several types of substrates materials in constructing the antenna. Two types of substrates that analyze and study by the researcher are Polyimide and Poly (methyl methacrylate) polymer matrix substrates. For this specific research study, the designed and analyzed methodology is conducted using CST microwave studio software using two types of substrates which are polyimide (Lossy) with dielectric constant equal to εr = 3.5 and Poly(methyl methacrylate) polymer matrix with dielectric constant equal to ϵr = 4.9. This analysis is to compare the bandwidth performance of polyimide and Poly (methyl methacrylate) polymer matrix substrate that been use in solar antenna’s studies by many researches. For these types of research analysis, the aim of this study specifically to have a material that gives high performance in bandwidth. Choosing of suitable material as the substrates also one of the ways to improve the antenna design performances. Broader bandwidth will have the capability to transfer higher data rates. Performances characteristics of the microstrip circular patch antenna of each of the substrates materials designs are also obtained and compared.
Energy Saving in a Process Plant using a Steam Accumulator
Authors: Ayyappan Preethy , Kumar Jeyanandan , Kumar Venkiteswaran Vinod
Published: July 2019

This work was done in a process plant, where the steam demand was mostly steady but sometimes it peaks-up to the double of the average demand for a short period of time. The plant, in addition to a 5000kg/hr boiler, was continuously operating a huge capacity boiler to encounter this brief situation. This was resulting in unnecessary energy loss. As a solution, a steam accumulator was added on and only a lower capacity boiler was run. The short time peak demand of the plant was satisfied by supplying extra steam from the accumulator for a short period of time. By doing so a saving of about RM 300,000/year was achieved.
The Effects of Water Flow Rate On The Air Entrainment Process From Vertical Plunging Water Jet With Downcomer
Authors: Budiarso  , Warjito  , Putra Pamungkas Bima
Published: July 2019

This study is intended to research the characteristics of bubbles produced by the phenomenon of air entrainment. This phenomenon is used in the Jameson cell, a flotation system used to separate valuable minerals from impurities. This process has proven successful in providing high separation efficiency. However, the characteristics of hydrodynamic bubbles and water entrainment have not been widely described. Research was set up in the form of a water loop consisting of a pump, flow meter, nozzle, downcomer, and water box. Data collection is done by using a digital camera and a high-speed digital video camera with a backlighting system. The resulting image is processed with software to obtain quantitative data. Results indicate that increasing the water flow rate also causes the ratio of air to water to increase (air entrainment).Air Entrainment is natural phenomenon air carried out as a result of a fluid jet stream. Mass transfer deepens penetration because a high jet speed produces bubbles and tends to force those bubbles towards the flow. Increasing the water flow rate will expand the surface roughness to produce more bubbles. Thus, it can be concluded that there are three phenomena that will affect whether or not the discharge will increase the air entrainment process: depth of bubble penetration, area of bubble dispersion, and air entrainment rate.
Effect of Iron Sand in Single Basin Solar Still: Experimental Study
Authors: Mugisidi D , Cahyani R S , Heriyani O , Agusman D , Rifky
Published: July 2019

The aim of this experiment was to study the effect of iron sand in a single solar still. The study was conducted on an open floor at the Faculty of Engineering, Muhammadiyah University Prof. DR HAMKA in Jakarta, Indonesia between August – September 2018 using two solar stills made of 2 mm stainless steel (420 mm x 305 mm) covered with 3 mm glass with a slope of 30 degrees. Iron sand was taken from Glagah beach, Kulonprogo in Yogyakarta, Indonesia. One solar still contained 20 mm height of iron sand with 15 mm height of water, while the other one contained 20 mm of water without iron sand and was used as a control. The experiment results showed that the efficiency of solar still containing iron sand was 1.5% higher than the control.