bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractAs 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.