bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Analytical Model for the Estimation of Three-phase Rock-soil Thermal Conductivity for Geothermal Utilization
Authors: Jia G S , Tao Z Y , Meng X Z , Zhang L Y , Chai J C , Jin L W
Published: July 2019

As a kind of clean energy resource, geothermal energy is widely utilized in many fields, especially for heating and ventilation through heat exchangers buried underground. The use of geothermal heat exchange system will contribute to energy saving as well as building sustainable, therefore it has become more and more popular in recent years. Rock-soil thermal conductivity plays a noticeable role in the performance of ground buried heat exchanger. In the present study, a new analytical model was proposed to describe the spatial structure of the multiphase rock-soil and relative position of solid, liquid and gas phase. Through analyzing the relationship among different phases and coding FORTRAN program, the model structure parameters can be obtained for the calculation of parallel thermal resistances. The expression of the thermal conductivity derived from the model was then applied to obtain the thermal conductivity of the Tripoli sand from North Africa, before the results were compared with previous tests. After comparative analysis, the newly proposed model in this study was proved accurate in predicting the thermal conductivity of the chosen soil with around 20% averaged relative error, which will contribute to the prediction of rock-soil thermal properties as well as the design of ground buried heat exchanger.
Numerical Investigation of an Innovative Metal Structure in a PCM Based Heat Sink
Authors: Xie Jinlong , Fah Choo Kok , Xiang Jianhua , Mun Lee Hsiao
Published: July 2019

Numerical simulations were performed to examine the time-dependent melting in a PCM enclosure with two designs of conductive metal fins: a baseline design with conventional heat sink fin structure and a topologically optimized innovative structure. Two orientations of the PCM enclosures were investigated to characterize the orientation effects on the behaviours of PCM melting. The proposed simulation model was firstly validated by the published experimental results. The simulated device temperature, material phases and flow fields within the PCM enclosure developed under different operating conditions were presented and discussed. The simulation results showed that the optimized design generally outperformed the baseline design by obtaining a lower device temperature and alleviating the effects of orientations. At q = 50,000W/m2, the optimized design achieved a maximum temperature reduction of 8°C under Orientation 1 and 2.5°C under Orientation 2 in comparison to the baseline during the main stage of PCM melting. It was suggested that the promoted heat transfer performance by the optimized design was attributed to the improved heat diffusion capability as well as the intensified natural convection provided by its innovative metal structure.
Investigation of water cooled aluminium foam heat sink for concentrated photovoltaic solar cell
Authors: Cheong Tan Weng , Huat Saw Lip , San Thiam Hui , Yusof Farazila , Wang Chin-Tsan , Chian Yew Ming , Kun Yew Ming
Published: July 2019

Concentrated photovoltaic cell (CPV) is a popular renewable source nowadays. It has high efficient yet cost effective energy harvesting system available in the market. The performance of the CPV depends strongly on the temperature of the solar cell. The efficiency reduces as the surface temperature of the CPV increases. It is crucial to reduce the temperature of the CPV and maintains a small temperature variation along the surface of the CPV. Metal foam is an ideal solution for a CPV thermal management system. It helps to enhance the mixing of coolant due to its porous characteristics and lead to higher heat transfer rate and reduce the overall average temperature of a CPV. The main objective of this study is to enhance the heat removal rate along of the CPV. Aluminium foam is used as a heat sink to removal the heat generated. The effects of porosities and pores density (PPI) of the aluminium foam are measured against the thermal performance. Computational thermal fluid dynamics is conducted to study the thermal performance of aluminium foam heat sink. The parameters required for the simulations are extracted from literature. The results suggested that aluminum foam is able to enhance the heat removal and maintains better temperature uniformity of the CPV. 10PPI aluminum foam with porosity 0.682 provides the most optimum results with average temperature of 55.1 ˚C and temperature different of 7.4 °C at flow rate of 40 g/s. This approach is suitable to promote the efficiency of the CPV and prolong the cycle life.
Review a Decade of BP’s Technology Roadmap on the Next Generation Biofuels Development
Authors: Chew B C , Shen X B , Ansell J , Hamid S R , Oh Y P
Published: July 2019

Philip New-the ex-CEO of BP Biofuels proclaimed in 2007: the emergence of biofuels involves two value chains-agriculture and energy, where both mature industries are connected to new national/regional policy. This has opened various opportunities for developing countries to tie business relationships through BP’s investment into non-food next-generation biofuels (NGB) feedstocks farming. This study reviewed all BP’s NGB development projects undertaken from 2006 until 2016. Secondary data was collected through media, corporate websites/reports and newsletters. Next, the NGB development projects were mapped into a technology roadmap (TRM). From this case study, it is hoped that BP’s pursuance on the NGB development could be referred by other oil companies that would have a similar intention of the NGB developers.
Natural Brise Soleil: The Effects of Vegetation Shading on Thermal Environment of Residential Buildings in Hot and Humid Tropics
Authors: Mari T S , Kuppusamy S , Gunasagaran S , Srirangam S , Ang F L
Published: July 2019

In hot and humid tropics, excess solar gain in buildings results in high cooling load. Shading is a common strategy used to protect the building’s skin from excessive solar exposure. Vegetation shading is often used minimize the incident solar radiation and cool the building and affect the building’s energy performance. Thus, the study present findings on effects of vegetation shading on indoor and outdoor thermal environment in the hot and humid tropics of Malaysia. The aim of the study was to assess the effects of vegetation shading on the thermal environment of urban housing. An experimental study was conducted to determine the effects of vegetation on two residential buildings of 2 1/2-storey of typical materials and construction. Findings from the study evidence that vegetation has significant effects in modifying the microclimate by shading and evapotranspiration process. The results show that the outdoor temperature of CS1 (with vegetation) is significantly lower (3.3°C) in comparison with CS2 (non-vegetated) as the effects of vegetation shading. There is also a significant reduction of 3.4°C in the indoor temperature compared to the outdoor at CS1. The results show that vegetation shading is an excellent passive cooling strategy for buildings, potentially improving thermal environment and conserving energy.
A Deep Review of Fly Wheel Energy Storage System Made from Aluminium Material
Authors: Saeed Atif , Talha Muhammad , Jaffer Mutafa , Yousuf Khan Hayyan , Haider Ali , Ali Wajahat
Published: July 2019

Nowadays, the most critical crisis for man at hand is to advance itself towards the most effective and efficient means. Hence forth, the flywheel experiment has been performed, to understand and discover more uses for this apparatus. The flywheel itself is a wheel that is used mainly as a prime mover for most every day machines such as steam locomotives, mechanical water wells, etcetera. A more advanced use for this wheel is a flywheel energy storage system which is used to generate clean and environment-friendly energy. This study focusses on optimizing aluminium flywheel and come up with an RPM imposes minimum stress on flywheel and in addition could yield maximum efficiency. At the end it was concluded that low RPM ranging from 1100-1200 could yield a maximum efficiency of 80% approx…
Optimization of the Design Parameter for Standing Wave Thermoacoustic Refrigerator using Genetic Algorithm
Authors: Yuan Ong Jing , Jin King Yeong , Huat Saw Lip , Keng Theng Kai
Published: July 2019

Standing wave thermoacoustic refrigerator has a potential of replacing conventional vapor compression refrigeration system due to several factors. Firstly, this green technology does not contain any harmful chemicals or ozone depletion refrigerant. In fact, it uses the sound wave to generate the cooling effect. Thus, it is friendly to the environment. Besides, this technology is affordable, lightweight and easy to be constructed too. However, it has a low coefficient of performance compared to conventional refrigerator with the same cooling capacity. Recently, there is no noticeable breakthrough in the research of this technology. In this study, genetic algorithm is used to optimize the design parameters of the standing wave thermoacoustic refrigerator system to achieve the highest coefficient of performance. Multi-Objective Genetic Algorithm is used to provide the performance trend of a standing wave thermoacoustic refrigerator system. There are five normalized parameters which will undergo optimization using genetic algorithm, namely normalized stack length, normalized stack center position, blockage ratio, drive ratio and normalized gas thermal penetration depth. The results show that the highest COP that can be achieved by a thermoacoustic refrigerator system (working gas = air, temperature = 300 K and pressure = 1 atm) is 4.8904. The coefficient of performance is about 120.3 % higher than the previously published data. A standing wave thermoacoustic refrigerator prototype is built based on the optimized results obtained from genetic algorithm, whereby the system is operating under no load condition. It is found that the experimental results agree well with the optimization results.
Comparative start-up between mesophilic and thermophilic for acidified palm oil mill effluent treatment
Authors: Fikri Hamzah Muhammad Arif , Md Jahim Jamaliah , Mohamed Abdul Peer
Published: July 2019

Malaysia is one of the largest palm oil producers in the world and its most abundant waste, palm oil mill effluent (POME), can be used as a feedstock to produce methane. Anaerobic digestion is suitable for treating the POME for methane production due to its tolerance to high strength chemical oxygen demand (COD). This work emphasizes the study of conditions during the start-up of anaerobic digestion of acidified POME between thermophilic (55 °C) and mesophilic (37 °C). The pH of the digester was maintained throughout the experiment at 7.3±0.2 in 1000 ml working volume. The study showed that the thermophilic was much faster to stabilize on the 44th days compared with the mesophilic on the 52nd days. Furthermore, the thermophilic also indicates higher biogas production, which was 0.60 l/l/d compared with 0.26 l/l/d of mesophilic. This result can be supported by the COD removal of thermophilic which also higher.
Treatment of produced water mixed with polymer from petroleum production
Authors: Thanamun C , Limsuwan P , Maneeintr K
Published: July 2019

In the petroleum industry, polymer flooding is one of the main methods in enhanced oil recovery (EOR) that applies a water-soluble polymer such as partially hydrolyzed polyacrylamide (HPAM) to increase oil production. It is added to the flooding water to improve the oil movement. During the process, water is produced as a by-product along with oil and gas production. Moreover, produced water with polymer is more difficult to treat than that from conventional water-flooding process because it is complex and highly contaminated wastewater. The proper technology is required to treat this kind of wastewater and reuse it for oil production. Furthermore, the small to fine particles in the produced are needed to be removed because these particles can plug the reservoir in the oilfield. One of the main treatment processes is to apply the coagulant to agglomerate the fine particles and remove them before injection the water into the reservoir. Therefore, the objective of this study is to treat the produced water mixed with HPAM from petroleum production by using coagulants like polyaluminium chloride (PAC) and to investigate the effect of parameters such as coagulant dosage and polymer concentration on the treatment of produced water. The results are compared the performance with the conventional coagulant, potassium aluminum sulfate (potassium alum). The operating parameters of this study are coagulant dosage ranging from 300 to 900 mg/L and HPAM concentrations from 500 to 2,000 mg/L. In addition, the turbidity, as well as total suspended solids (TSS) are also studied. The results indicated that with an increase in HPAM concentration, the TSS and turbidity increase gradually under the same conditions. The results show that with 900 mg/L of coagulants, TSS and turbidity can be removed up to 89% and 94% with PAC and 39% and 27% with potassium alum, respectively. PAC can provide higher performance over alum at the same conditions; thus, leading to the reduction in chemical consumption and cost. Consequently, this method can be applied to use in the wastewater treatment from oil production with polymer flooding before injecting this produced water back into the reservoir.
Performance Improvement Optimisation of a Photovoltaic System located at the Tropical Climate using Water-Film Cooling Method
Authors: Mah Chia-Yi , Lim Boon-Han , Wong Chee-Woon , Tan Ming-Hui , Chong Kok-Keong , Lai An-Chow
Published: July 2019

The temperature rise of solar panels can cause significant reduction in the energy generation especially for the countries located in tropical climate region. It is more effective to use water-film for cooling the front surface of solar panels, but the energy consumption of the water-cooled photovoltaic system (WCPV) needs to be reduced to obtain a higher net energy gain. In this study, a discrete water-supply water-cooling system (D-WCPV) has been proposed to reduce the energy consumption of the water pump and to improve the performance of a retrofit or building integrated photovoltaic system through reduction of the panel temperature. The discrete mechanism utilises a relay to switch on the power supply of the water pump whenever the temperature of the solar panel has reached the threshold of 45 °C. It is found that minimum flow rate for the D-WCPV is 8 L/min to form a full coverage of water on the surface of the solar panel for providing an uniform cooling effect and hence providing a better performance improvement. A comparison has also been made for the continuous water-supply water-cooling system (C-WCPV) and D-WCPV. D-WCPV has two advantages over C-WCPV as follows: 1) the energy consumption of the water pump operating at flow rate of 8 L/min has been reduced by 86.7% from 0.057 kWh/h to 0.0076 kWh/h and (2) the net energy gain (NEG) of the system at solar irradiation ranging from 806 Wh/m2 to 950 Wh/m2 has been increased by 80.2% from 5.5% to 10.0%.
Numerical investigation on the performance of a honeycomb-shaped channel
Authors: Yang Xi , Guo Qiang , Zhang Liyu , Liu Xing , Lu Zhao , Meng Xiangzhao , Jin Liwen
Published: July 2019

A certain number of researches have been implemented on the fluid flow and heat transfer in fractal-like channels for their excellent heat transfer performance, which can be attributed to the effects of the bifurcations causing diffluence flow and confluence flow on thinning thermal boundary layer and inducing secondary flow. In this paper, the three-dimensional numerical models of the honeycomb-shaped minichannels were established to research the effects of branching angles on the hydrodynamic and thermal characteristics in the case of laminar flow. A comparative study was carried out to evaluate the performance of the current structures with the straight minichannel based on approximately the same hydraulic diameter, heat flux density and convective heat transfer area. In the simulation results the superiority of overall performance of the honeycomb-shaped minichannels over the straight minichannel was discovered. In addition, the studies showed that the honeycomb-shaped minichannel with smaller branching angle attained the higher overall performance within the relatively high Reynolds number range. It was found that the honeycomb-shaped minichannel with branching angle of 60° yields the best overall performance at the Reynolds number of 400.
Analysis of the human health damage and ecosystem quality impact of the palm oil plantation using the life cycle assessment approach
Authors: Obaideen Khaled , Chai Tan Yong , Seng Yap Pow , Awang Muhamad , Abd Ghani Abdul Azim , Subramaniam Vijaya , Cent Tai Vin
Published: July 2019

In recent years the palm oil has been criticized because of its impacts on the environment and human health. Therefore, this study focused on the investigation of human health and ecosystem quality impacts that arose from the plantation of fresh fruit bunch of palm oil by employing an open-source software, namely OpenLCA version 1.5. The life cycle assessment approach was used for the analysis of the investigated impacts. The effects of land use changes on the human health and ecosystem quality were assessed. By employing ReCiPe Endpoint methodology in life cycle impact assessment phase the total ecosystems impact 0.00017 species per year while total human health damage was 0.00146 DALY The results showed that the land use change has an impact on all the impacts categories except the freshwater eutrophication, freshwater ecotoxicity, ozone depletion, terrestrial ecotoxicity, and terrestrial acidification. In addition, the analysis showed that the application of the fertilizers and pesticides were the main contributor in all the impact categories. The results show that transportation is not the major contributor in any one of the impact categories
Effect of Different Carbon Additives on Hydrogen Storage Properties of AZ31 Magnesium Alloy by High Energy Ball Milling and Equal Channel Angular Pressing
Authors: Huang SJ , Rajagopal V , Chen YL
Published: July 2019

This study investigated the effect of carbon additives on the hydrogen storage performance of AZ31 Magnesium alloy. Different weight percentages (0 wt.%, 3 wt.%,) of activated carbon (AC), carbon black (CB)and graphene (G) were used as catalyst to explore the effect of different carbon material additives on the hydrogen storage performance. In addition, the effect of employing different processes like High energy ball milling and Equal channel angular pressing on hydrogen storage performance was also examined. AZ31 magnesium-based composites with different carbon materials were prepared through stir casting method. Micrographs were recorded through OM (optical microscope) and SEM (scanning electron microscope with EDS). The average particle size of the prepared powder samples was measured using particle analyzer. The hydrogenation kinetics was measured using Sievert’s type apparatus. It was found that the addition of carbon materials and refined microstructures effectively enhanced the hydrogen storage performance of AZ31 Mg-alloy. In High energy ball millingprocess AZ31-3G (graphene) reaches the maximum storing capacity of 6.83±0.04 wt.% within 792±144.34 seconds and desorbed the entire hydrogen in 143 seconds. And in the case of ECAP process, the alloy AZ31-3CB (carbon black) reaches the hydrogen storage capacity of 6.72±0.05 wt.%.
An Urban Based Smart IOT Farming System
Authors: Mungai Bryan Njoroge , Fei Thang Ka , Vinesh Thiruchelvam
Published: July 2019

Recent technological developments have led to the emergence of new trends in agriculture to ensure increased production through sustainable utilization of resources. One of the new trends is Precision Agriculture (PA). However, like many new emerging trends, PA is faced with a number of uncertainties and hurdles. One of the major issues and hurdles in precision agriculture is the uncertainty of optimum application of resources necessary for optimum yield production while minimizing resource wastage for sustainable agricultural production. Therefore, this paper presents a fuzzy based Decision Support System (DSS) to intelligently allocate water and fertilizer used in crop production based on the age of the plant and data collected from the soil and surrounding environment with the aid of a network of sensors. An embedded hardware system consisting of a Cartesian robot has also been implemented to ensure effective application of the fuzzy derived decisions. Two Fuzzy Inference Systems (FIS) consisting of linear, non-linear Membership Functions and a 149-rule base for the PA system have been developed in MATLAB, implemented using Arduino microcontrollers and tested on spinach plants whereby results show that the linear FIS is able to achieve more accurate results in terms of the quality of yield realized and resource utilllisation. Resource utilllisation comparison with other systems in literature reviewed is also done whereby the DSS is able to save up to 2031 ml and 524 ml of water and fertilizer respectively.
Digital Light Processing 3-Dimensional Printer to Manufacture Electrolyzer Bipolar Plate
Authors: Husaini Teuku , Kishida Ryuhe , Affiqah Arzaee Nurul
Published: July 2019

Bipolar plate is one of the largest and most important components in Polymer Electrolyte Membrane Electrolyzer and Fuel Cell that functions as a cell separator, electrical and heat conductor, reactant feed distributor, for the flow of gas-liquid mixture and supporting components for the Membrane Electrode Assembly. In general, injection, compression moulding or Computer Numerical Control-machines are commonly used to produce bipolar plate. These methods, however, cannot be used to produce complex 3-dimensional shapes, such as vertically inverted cone shape or creating a channel inside the plate. By using a 3-dimensional printing machine with laser-based stereolithography or digital light processing, complex design problems and problems in making channels in the plate can be solved easily. In this study, polymer-based bipolar plate was developed using 3-dimensional printing technology which was made conductive by introducing nickel and gold layers through spray coating and electrocoating processes. The nickel layer was optimized by controlling the applied voltage during electrocoating. Since low voltage formed very thin layer whereas high voltage caused “burning” of the sample, applied voltage of 5V was found to be the optimum condition. Employment of gold layer increases the conductivity from 300 S cm−1 to 400 S cm−1 which enabled the corrosion current density to drop to 0.470 uA cm−2, meeting the standard set by US Department of Energy. The porosity test also proved that the bipolar plate was impermeable to hydrogen gas. Therefore, this manufacturing method has great potential to be used for the production of sophisticated electrolyzer cell or fuel cell in the future.
Human Interaction Theory for Sustainable City
Authors: Illia Ibrahim Filzani , Diyana Nizarudin Norhanis
Published: July 2019

In relation to open spaces, Malaysia has received very little attention from researchers, unlike other countries where many studies have explored how human needs are fulfilled by urban open spaces. It is strongly believed that aspects such as the amount of urban open spaces per inhabitant, public parks and recreational areas are often mentioned as vital factors to make the city livable, pleasant and attractive for its citizens. This paper is undertaken to fill the knowledge gap of how human interacts in the urban open spaces that will then be developed as among the indicators for city sustainability. The objectives of this paper are to identify the human-nature and human-human interactions, at the same time identify the perceived benefits from physical, social and natural interactions towards open spaces. The expected outcome of this study is, it will help to emphasize the importance of citizen participation towards the open spaces and how it affects the level of sustainability. Furthermore, it will help in improving urban planning strategies and policy decision for the sustainability of the city.
Space optimization of concentrator photovoltaic systems based on levelized cost of electricity in solar power plant
Authors: Oon Li-Voon , Tan Ming-Hui , Wong Chee-Woon , Yew Tiong-Keat , Chong Kok-Keong , Tan Woei-Chong , Lim Boon-Han
Published: July 2019

Inappropriate layout design of concentrator photovoltaic (CPV) systems in the solar field will incur optical losses due to mutual shadowing among adjacent CPV systems. This will deteriorate the energy generation of a solar power plant (SPP). The trivial solution is to increase the separating distance between adjacent CPV systems. Unfortunately, it causes ineffectiveness in land usage and will be reflected to an increase in land-related costs. Therefore, optimization of layout design is an important procedure to determine the best trade-off between land usage and energy generation. The levelized cost of electricity (LCOE) of the SPP must be competitive to attract the interest of investors venturing into the solar energy business. A new computational algorithm has been proposed to optimized the field layout system of the CPV system by using the local weather data with the consideration of the shadowing effect. In this paper, a case study has been conducted in Kota Kinabalu, Malaysia to evaluate the performance of CPV systems in the SPP with different D/L ratios. The simulated results show that the optimized field layout for the CPV systems is at D/L ratio of 2.25, which accommodate the lowest value of LCOE.
A computational analysis of construction – operation – environment cost of real estate development projects
Authors: H A Tran Tuan
Published: July 2019

Similar to many highly populated cities in South East Asia, Ho Chi Minh City (HCMC) is the largest city of Vietnam acting as the economic driver for the whole country. Its urban life attractions and economic opportunities have drawn people across the country and the region, resulting in a high demand of housing. HCMC becomes a hot spot for many local and foreign real estate investors and developers. Many property development projects in HCMC have been rapidly increasing in recent years. However, many real estate developers usually pay more attention on profit-related criteria while neglecting sustainable aspects, partly due to lack of knowledge and an appropriate tool. A construction - operation – environment cost analysis workflow based on an urban simulation tool coupled with other scripting and modelling tools is proposed to quantify environmental cost and operational cost besides construction cost for a real estate development project in HCMC. Three alternative design scenarios are derived from a baseline at the early stage of design process originally provided by a developer. Computational analysis from these scenarios on construction cost in comparison to operational and environmental cost provides more information to the investment decision making process allowing the developer not only to meet their investment return expectation but also to take environmental impact and residents’ expense during the project’s life cycle.
An Innovative Autoclaved Aerated Concrete (AAC) with Recycled AAC Powder for Low Carbon Construction
Authors: Rafiza AR , Chan HY , Thongtha A , Jettipattaranat W , Lim KL
Published: July 2019

Recycling of materials, in particularly concrete was not frequently practiced in construction and moreover no study has been carried out yet. Furthermore, the environmental impact of recycling in construction was not known and no study has been carried out, thus now it leads to give an abundance of wasted concrete at site. Autoclaved aerated concrete (AAC) is one of the lightweight concretes that commonly used in construction. AAC is relatively light in weight, having lower thermal conductivity, higher heat resistance, lower shrinkage, and faster in construction process when compared to the conventional concretes. AAC consist of silica sand, cement, lime, water and expansion agent. To reduce the construction waste, an innovative AAC block has been developed by using recycled AAC in powder form to replace sands in the manufacturing process. The new developed AAC was conducted by replacing sand with recycled AAC in ratio of 0%, 15%, 20%, 25%, 30%, 45%, 40% and 45%. Microstructure analysis were conducted using optical microscopic and scanning electron microscopic (SEM) while the chemical analyses were conducted using X-ray diffraction (XRD). Mechanical tests such as density, compressive strength, flexural strength and water absorption also have been carried out. It could be observed that by replacing the sand content with recycled AAC, AAC with fine recycling powder content of 30% by weight has a compressive strength that is approximately 16.1% greater than conventional AAC and is between 30-110% higher than any value obtained by utilizing industrial waste product.
Optimization of Alkaline Pulp Extraction from Napier Grass Using Response Surface Methodology
Authors: Yong Kang Low , Ayu Haslija A.B
Published: July 2019

Napier grass which has several types of them has been studied by researchers for few applications such as biofuel, sugar and pulp production. This research focused on specific type of Napier grass which is the Dwarf Napier due to high cellulose content to produce pulp. Delignification of Dwarf Napier grass was carried out by soda anthraquinone pulping under varying conditions selected according to experimental design software with three factors. The influence of these three factors including concentration of sodium hydroxide (15%, 17.5% and 20%), concentration of anthraquinone (0.05% and 0.1%) and duration of cooking time (30, 60 and 90 min) on pulp yield was studied. 18 runs of experiment were conducted and the result obtained was used to analyse the optimized condition for pulp extraction by using RSM. Results indicated that the optimized response obtained while Napier grass stem is treated with 17.5% sodium hydroxide and 0.05% AQ with 66 mins of cooking time meanwhile the predicted yield is 34.87 %. However, the actual pulp yield obtained (36.38%) is higher than the predicted yield. The pulp which extracted with optimized condition is then bleached with hydroxide peroxide. Fourier transform infrared spectroscopy (FTIR) was used to characterize the raw grass fiber and pulp obtained. Napier grass is successfully demonstrated to be an effective alternative source for producing paper pulp. In the this study Dwarf Napier grass fibres were successfully pulped applying soda AQ process although the obtained pulp is not as high as the studied done before due to the limitations. FTIR analysis also confirmed the removal of lignin as well as most of the hemicellulose during the pulping process. Therefore, the abundance and fast growth of Napier grass are an added advantage as an alternative non-wood source for papermaking
Performance Evaluation of a Building Integrated PV (BIPV) at Heriot-Watt University Malaysia
Authors: Arnaout M. A. , Yun Ii Go
Published: July 2019

Building Integrated Photovoltaics (BIPV) is a promising technology that combines the generation of energy into the building structure where the modules act as building material or blend completely with architectural design. This study analyses the performance characteristics of a proposed BIPV system for Heriot-Watt University Malaysia building, the system is designed with aim to utilize the curved roof area of the building. The available roof area of 7725 m2 is curved with varying tilt angles from 1.5° to 26°. The environmental plugin Ladybug integrated within Grasshopper was used to visualize and estimate the energy potential from the roof surface in Rhinoceros 3D modeling software. Additionally, detailed system simulations are conducted with PVSyst software. Eight proposed system variants of different PV technologies and modules types are studied with capacities of 411.8 kW to 1085.6 kW. The recommended system has a size of 1085.5 kW and utilizes Thin-film CdTe PV modules. The system generates 1415 MWh annually with a performance ratio of 84.9%, which saves 62.8% of the electricity bill and has an estimated cost of 901 thousand USD. Installation of the proposed system should preserve the aesthetical value of the building’s roof and satisfy BIPV rules.
Screening the factors affecting torrefaction of palm kernel shell by using Plackett-Burman Design
Authors: Indum Panadda , Mueanmas Chokchai
Published: July 2019

Torrefaction is a thermochemical treatment for the production of solid fuel from biomass which promotes the increasing of fuel quality. This process involves the heating of lignocellulose at temperature range 200°C – 320 °C in the absence of oxygen. The decomposition of cellulose, hemicellulose and lignin depends on several parameters. This research aims to investigate the screening of factors affecting torrefaction of palm kernel shell (PKS) which is a waste from oil palm tree. A Plackett–Burman experimental design is applied for screening the influence of operation parameters such as temperature, time, oxygen feed ratio, heating rate and biomass size. Mass yield (MY), moisture content (MC), volatile matter (VM), fixed carbon content (FC), ash content (AC) and calorific value (CV) are analyzed as the response to evaluate the performance of torrefaction conditions. The significant parameters are selected based on the analysis of variance (ANOVA) results. The results show that the temperature, time, oxygen feed ratio and biomass size are significant parameters. The fuel properties of torrefied product were compared with the standard for solid fuel. These results show that the quality of torrefied PKS satistifies the standards. Therefore, the torrefaction process can be used as the potential technique for improve the quality of PKS fuel properties.
Assessment of the fuelwood value chain in Yobe, Nigeria
Authors: Ali B , Saadun N , Alias M A , Norizah K
Published: July 2019

This study aims to assess the characteristics of the fuelwood value chain in Yobe, Nigeria. Data were collected through state government records, direct observations, focus group discussions, and interviews with key informants using open-ended questionnaires. Results showed that the fuelwood value chain comprises five functions: harvesting, transporting, trading, retailing, and consumption. The analysis further revealed five sub-chains characterized by actors in which two sub-chains were classified as formal (registered with associations and functioning with licenses) and three were classified as informal (not registered with an association and functioning without license). The presence of informal actors in the value chain observed in this study is widespread due to weak governance, high fuelwood demand, and corruption. Consequently, their poor practices have added extra pressure on the forest and is threatening the environment, fuelwood availability, accessibility, and market. The intrusion of informal actors needs to be properly addressed by the government through measures that include an efficient and flexible licensing system, strict implementation of fuelwood regulations, active monitoring, increase of awareness on the benefits of licensing and operating as registered actors in an organized group on job security, profits, and the environment and improved supervision of the forest laws’ enforcement agents to curtail corruption.
Investigation on surface morphological and optical properties of black silicon fabricated by metal-assisted chemical etching with different etchant concentrations
Authors: Noor N A M , Pakhuruddin M Z
Published: July 2019

In this study, the surface morphological and optical properties of black silicon (b-Si) fabricated by two-step metal-assisted chemical etching (MACE) process are investigated. The two-step MACE combines low-temperature annealing of silver (Ag) thin film to produce Ag nanoparticles (NPs) and short etching duration of crystalline silicon (c-Si) wafer. The etching is carried out in HF:H2O2:DI H2O solution for 70 s with different etchant concentrations (represented in the form of volume ratio). The MACE process produces b-Si nanopores on the wafer. Compared with planar c-Si reference, broadband reflection (in 300-1100 nm wavelength region) of the b-Si is significantly lower. B-Si wafer with volume ratio of 1:5:10 exhibits the lowest broadband reflection of 3% at wavelength of 600 nm, which is believed to be due to refractive index grading which leads to enhanced light coupling into the b-Si wafer. The best b-Si wafer (with lowest reflection) shows 50 nm average pillar width and 300 nm height. The increased broadband light absorption results in the highest maximum potential short-circuit current density (Jsc(max)) of 40.9 mA/cm2. This represents 55.4% enhancement, if compared with the planar c-Si reference wafer, assuming unity carrier collection.
Generating Efficient Production Plans for Heater Manufacturing Industry
Authors: Kai Sin Chong , Tan Ching Ng , Lip Huat Saw
Published: July 2019

Nowadays, manufacturers in Malaysia as well as global have been facing challenges in order to overcome the uncertainty of demand fluctuations, supplier capability and achieved customer expectations and satisfaction. To increase competitiveness in global market, manufacturers from various aspects keep one’s eyes open on lean implementation and factory automation. This journal aims to develop an efficient production plans for heater manufacturing industry in order to achieve higher productivity and reduce wastes. With the traditional production line which had been implemented for years, several difficulties have been faced by company. For instance, abundance numbers of worker in production line which is not fully utilize and product quality is highly depends on skilled operators due to manual process. Smoothness index is used to determine the improvement of proposed production plan. Although minimization of smoothness index is essential in solving line balancing problem, this research has highlighted that researcher or company shall not rely on smoothness index alone while other aspect such as acceptable productivity and minimization of human resource should be considered.
Performance Evaluation of Absorber Rod Type Solar Air Collector
Authors: Saberi Zainab , Fudholi Ahmad , Ibarahim Zahari , Sopian Kamaruzzaman
Published: July 2019

Solar air collector is a device that collects heat energy from the sun where the solar energy is converted to heat energy. A good solar air collector is when it can absorb maximum heat and can reduce as minimum as heat loss possible. In this study, a solar air collector device has been designed and constructed by attaching aluminium rod of 210 pieces with height 2 cm on the absorber plate to increase the heat transfer surface area. Apart from that, fin also built in airway to increase transfer of heat from plate absorber to air flow. There are 4 parameter of intensities value and mass flow rate is changed in this experiment which are 101.5 W/m2, 302.4 W/m2, 530.6 W/m2 and 720.0 W/m2 while for the mass flow rate is 0.0236 kg/s, 0.0340 kg/s, 0.0452 kg/s and 0.0584 kg/s. The aim of this study was to investigate the effect of mass flow rate and the solar intensity in improving the efficiency of thermal solar collectors. The results showed that the efficiency is between 57.2% to 77.4%. Maximum thermal efficiency mass flow rate recorded at 0.0584 kg/s with radiation intensity of 530.6 W/m2. Changes in temperature, ΔT are decreased when mass flow rate is increased which 19.0°C to 1.2°C is depending on the solar radiation intensity.
Potential Evaluation of Wind Energy in Kuala Terengganu, Malaysia through Weibull Distribution Method
Authors: Saberi Zainab , Fudholi Ahmad , Sopian Kamaruzzaman
Published: July 2019

Malaysia faces many challenges in the development of wind energy as it is located in areas with slower wind speeds. Malaysia is located on the equator line where land and sea breezes can affect the wind regime. The wind does not blow uniformly and fluctuate by month and area. Therefore, the objective of this study is to determine the potential of the latest wind power in Kuala Terengganu. The scope of the study was not comprehensive because it focused only on Kuala Terengganu, Malaysia which is located at latitude 5° 23′ N and longitude 103° 06′ E. The wind data used in this study was obtained from the Malaysian Meteorological Department. The wind data that had been observed and collected was the wind direction and wind speed for year 2017 where the height of the sea level is 5.2 meters. This study uses the Weibull Distribution method as it shows a good consideration to estimate the density of wind power in Malaysia [1] The daily wind speed pattern for year 2017 can be seen that it has a corresponding pattern where it shows high wind speed at the beginning and end of the year. The wind speed frequency is also variable for the winds of the Northeast Monsoon and is almost constant during the south monsoon of the Southwest Monsoon and the Transition Monsoon. Overall, the potential of wind power in Kuala Terengganu is not too large. The annual average for 2017 is 2.01 m/s only. Wind power is high during the Northeast Wind Monsoon season.
Investigation of TiO2 and MWCNT Nanofluids-based Photovoltaic-Thermal (PV/T) System
Authors: Binti Rukman Nurul Shahirah , Fudholi Ahmad , Mohd Razali Nur Farhana , Hafidz Ruslan Mohd , Sopian Kamaruzzaman
Published: July 2019

Nanofluids as a new generation of cooling fluid has been found in recent years to improve the heat-transfer coefficient and enhance the system performance. This study presents investigation conducted on the performances of TiO2 and MWCNT nanofluids-based PVT systems. The preparation of nanofluids using two step method and dispersing of surfactant for a stable nanofluid. The experimental investigation with the effect of different concentration, mass flow rate (0.012 kg/s to 0.0255 kg/s) and solar radiation (500 W/m2 to 900 W/m2) on the performance of nanofluids-based PVT system is presented. The lowest temperature of the PV module and highest fluid’s change of temperature were recorded when the collector uses TiO2 fluid 1.0 wt% which is 2.01°C and 1.80°C.
Valorising fermentation effluent rich in short-chain fatty acids and sugars for biohydrogen via photofermentation by Rhodobacter sphaeroides KKU-PS1
Authors: Fitri Hanipa Muhammad Alif , Mohamed Abdul Peer , Md Jahim Jamaliah , Sobri Takriff Mohd , Reungsang Alissara
Published: July 2019

Growing fermentative chemical production will increase effluents from industrial fermentations containing short-chain fatty acids and residual sugars, which are exploitable for biohydrogen through photofermentation. Previous studies have concentrated on single substrates and photofermentation study using fermentation effluent from bio-succinate production containing residual sugars and short-chain organic acids has yet to be reported to the best of authors’ knowledge. Rhodobacter sphaeroides KKU-PS1 grown on succinate was used for hydrogen production from medium containing mixture of substrates mimicking final effluent from bio-based succinate production. Prior to that, hydrogen producibility test with succinate-only medium was carried out. Photofermentation from succinate by this strain yielded 1217 ml H2/l of maximum cumulative hydrogen with maximum hydrogen rate of 6.7 ml H2/l/h, comparable to malate which was previously reported as best single substrate for the strain. Hydrogen production profiles using mixed substrates was well-fitted by modified Gompertz model with maximum cumulative hydrogen and maximum hydrogen production rate of 1005 ml H2/l and 4.1 ml H2/l/h, respectively. Only glucose, xylose and succinate followed modified Gompertz model for substrate consumption. Instantaneous succinate consumption compared to extended lag time of 100h for consumption of both sugars indicated higher affinity towards short-chain fatty acid utilization during initial growth phase. Xylose showed highest overall substrate consumption signifying its importance for hydrogen generation, which continued after stationary growth phase started reaching a total of 91.9% consumption. Significant remaining substrate levels other than xylose suggested that the process was not inhibited by limited substrates. The study highlighted potential of fermentation effluents containing mixed substrates for biohydrogen, with further optimization needed.
Synthesis, Characterisation and Catalytic Activity of NiO supported Al2O3 for CO2 Hydrogenation to Carboxylic Acids: Influence of Catalyst Structure
Authors: Hasan S Z , Ahmad K N , Isahak W N R W , Pudukudy M , Masdar M S , Jahim J M
Published: July 2019

Utilisation and conversion of carbon dioxide into valuable chemicals and fuels are the promising ways to reduce carbon dioxide concentration in the atmosphere. In addition, the conversion of carbon dioxide into fuels, such as methane, methanol and formic acid has been proven a good method for hydrogen storage. In this work, the catalyst structure plays an important role in the production of formic acid and acetic acid at low temperature. Nickel oxide supported alumina catalysts were synthesised by using the solid-state fusion method at 550 °C and 700 °C. Calcined catalysts were characterised by X-ray diffraction, Brunauer-Emmett-Teller surface area, high-resolution field emission scanning electron microscopy, Auger electron spectroscopy with X-ray photoelectron spectrometer and transmission electron microscopy. Carbon dioxide hydrogenation was performed in the batch reactor. The products obtained were analysed by using high-performance liquid chromatography and gas chromatography with a thermal conductivity detector. The highest levels of formic acid and acetic acid production were 4.08 and 1.58 mmol/L, respectively.
Development of a Reduced Biodiesel Surrogate Fuel Model for Multi-Dimensional Computational Fluid Dynamic Simulations
Authors: Poon H M , Ng H K , Gan S , Chong W T
Published: July 2019

This work reports the development of a reduced biodiesel surrogate fuel model for multi-dimensional Computational Fluid Dynamic simulations. The model is derived using an integrated kinetic mechanism reduction scheme and the final chemistry comprises only 83 species. The model is well validated in zero-dimensional chemical kinetic calculations under a wide range of auto-ignition and jet-stirred reactor conditions. The fidelity of the model is also further assessed in two-dimensional simulations of a constant-volume combustion vessel with respect to the experimental results of soy-methyl ester combustion. The results obtained reveal that ignition delay, lift-off lengths and soot volume fractions are reasonably well replicated by the reduced model. Furthermore, the compositions of the reduced model are varied according to the saturation/unsaturation levels of various biodiesel feed-stocks, such as palm-methyl ester and sunflower-methyl ester. In this work, it is demonstrated that the reduced model can potentially be used as a universal surrogate fuel model to predict the reactivity of biodiesel feed-stocks with low degree of saturation (≤30%) in both kinetic and fuel spray simulations.