bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of semi-batch cultivation and extraction for maximal lipid production in Chlamydomonas sp. Tai-03
Authors: Tan Chung Hong , Show Pau Loke 
Published: April 2020

Abstract
Rapid improvements in bioseparation technology, new regulatory directives, product quality constraints, and the production efficiency have necessitated the development of more advanced and powerful downstream bioprocesses for biotechnology and biopharmaceuticals industrial. This has transformed in dramatically improvements in traditional bioseparation processes as well as the development of entirely new approaches. In this paper, we highlight some of these recent advances of integration of semi-batch cultivation and extraction for maximal lipid production in Chlamydomonas sp. Tai-03. This includes extractive cultivation, extractive bioconversion aqueous two-phase system, aqueous two-phase flotation, and newly developed liquid biphasic flotation. Alcohol/salt liquid biphasic flotation (LBF) with aid of ultrasonication which have the ability of killing two birds with one stone, it not only capable in cell rupturing, it also able to recover bioproducts simultaneously and continuously. The effect of varying crude feedstock concentration, flotation time, type of salt, concentration of salt, type of alcohol, concentration of alcohol, initial volumes of salt and alcohol were investigated. Microalgal biofuels or generation three biofuels have been widely recognized as potential replacements of fossil fuels. One of the most attractive option is the partial or full replacement of diesel fuel with microalgal biodiesel. Here, Chlamydomonas sp. Tai-03 was cultured using semi-batch cultivation to enhance its lipid production. Upon lowering the culture replacement fraction to 25%, the greatest biomass and lipid productivities were obtained at 1.23 ± 0.02 g/L/d and 239.6 ± 24.8 mg/L/d. After transesterification, palmitic acid (C16:0), oleic acid (C18:1), and linoleic acid (C18:2) were the main fatty acid methyl esters (FAMEs) present. These short-chain FAMEs and high productivities of Chlamydomonas sp. Tai-03 are suitable for biodiesel output.
Effect of in-situ carbon dioxide sorption on methane reforming by nickel-calcium composite catalyst for hydrogen production
Authors: Chen C H , Yu C T , Chen W H , Kuo H T 
Published: April 2020

Abstract
Hydrogen production plays an important role in hydrogen energy development. The steam reforming reaction is an efficiency way for hydrogen production via thermochemical method. But the hydrogen concentration was limited to be about 70% because of thermodynamic equilibrium. In order to avoid equilibrium limiting, the by-product CO2 removal during reaction was a suitable solution that drives the reaction to the right. In this study, the steam reforming of methane by in-situ CO2 sorption was investigated. The CaO material was used as CO2 acceptor because of its high capacity, fast kinetics and generality. The reforming catalysts were prepared by simple physical mixing of the 20 wt.% Ni/Al2O3 catalyst and CaO sorbents. The steam reforming of methane experiments was carried out by a fixed bed reactor. The experimental results indicate that the steam reforming of methane via in-situ CO2 sorption obviously obtained the H2 purity above 95% higher than conventional reaction without in-situ CO2 removal (~72% H2). The impurities involving CO and CO2 during reaction were suppressed below 0.5% before CO2 sorbent saturation. In this work, the highest H2 purity and CH4 conversion were founded to be 98.4% and 95% at 873K under steam/carbon ratio of four conditions. The methane steam reforming with high conversion strongly depended on the CO2 capture performance. The cause was attributed to the equilibrium limiting of reaction overcoming by in-situ CO2 sorption. It is also found that the product components and methane conversion was insignificantly affected in the range of space velocity from 7200 to 19200 cm3/hr/g.
First principles investigation on the nitrogen-doped planar aluminene for hydrogen storage application
Authors: Pedrosa G R , Villagracia A R , Bayasen D S , Lin H , Ong H L , David M , Arboleda N 
Published: April 2020

Abstract
With the rise of carbon emission daily, a pursuit for cleaner energy such as hydrogen fuel is necessary. Obtaining a good hydrogen storage is one of the main bottleneck to achieve a working hydrogen economy. Materials including two-dimensional systems have been widely investigated for potential hydrogen storage. In this work, the effects of nitrogen on the hydrogen adsorption on planar hexagonal aluminene was studied using density functional theory. Aluminene was decorated with nitrogen at different sites: top, hollow and bridge. Results showed that nitrogen was adsorbed at the top, bridge and hollow sites at a distance of 0.00Å to 1.80 Å with binding energies of 2.71 eV, 4.88 eV, and 3.44 eV, respectively. Comparing to the pristine aluminene, there was no major difference with its electronic and magnetic properties based on the density of states of the nitrogen-doped aluminene while the nitrogen atom gained some charges from the aluminium atoms based on the charge difference. On the other hand, a hydrogen molecule was adsorbed with binding energies ranging from 13.4meV to 26.3 meV close enough to the adatom on the decorated system. Minimal broadening of energy level was found from the density of states. This work shows that aluminene with nitrogen impurity can adsorb hydrogen molecules. However, high concentration of nitrogen will lower the hydrogen capacity of aluminene.
Density functional theory investigation on hydrogen adsorption on buckled aluminene
Authors: Villagracia A R , Ong H L 
Published: April 2020

Abstract
Hydrogen storage is one of the challenging components in hydrogen economy towards a cleaner energy. Two-dimensional materials are being explored as a potential hydrogen storage material. Adsorption of hydrogen on buckled aluminene was investigated using first principles with the incorporation of van der Waals correction via Tkatchenko-Scheffler method. Four possible adsorption sites were identified: top of the first layer, bridge, hollow, and top of the lowest layer. Critical results of energy calculations showed that hydrogen molecule can be physisorped on any sites of buckled aluminene with a binding energy of 0.77 eV without additional energy needed to store it. This physisorption is demonstrated in the density of states showing a slight broadening of energies. Hydrogen would prefer to be adsorbed as a molecule due to a dissociation barrier of 3.23 eV to recover the hydrogen. Another critical finding is that buckled aluminene has more possible hydrogen adsorption sites and higher binding energy than that of planar aluminene indicating a better candidate as a potential hydrogen storage material at a higher ambient temperature.
Suppression of hydrodynamic sloshing in liquefied natural gas tank with floating baffle: Experimental and numerical studies
Authors: Md Arif Ummul Ghafir , Loo Ching-Yun , Kang Hooi-Siang , Punurai Wonsiri , Quen Lee Kee , Lai Gavin Nai-Yeen , Chong Wen-Tong 
Published: April 2020

Abstract
A fixed anti-sloshing mechanism such as baffles which modifies the tank structure may lead to increment of the maintenance cost. This paper proposes a floating baffle, and reviews its investigation on the sloshing behaviour in a membrane-type tank model under unidirectional excitation with 30% and 50% of filling ratio. An LNG tank was numerically simulated in OpenFOAM under regular sinusoidal motion with an amplitude of 3 cm and excitation frequency set to the natural frequency at 1.1 seconds. Impulsive pressure on the tank wall was obtained, and then benchmarked with the experimental results from the pressure sensors. The simulation and experiment results showed an acceptable agreement with a root mean squared error of less than 10%. The findings are expected to become a significant reference for safer sea transportations such as conventional LNG vessels.
Effects of aquifer on heat exchange process in geothermal applications
Authors: Ma Zhendi , Jia Guosheng , Kong Qiongxiang , Xia Zhenhua , Jin Liwen , Meng Xiangzhao 
Published: April 2020

Abstract
Geothermal energy has been widely used in the field of the building heating through the ground heat exchanger (GHE). The groundwater flow in the aquifer is one of the significant factors affecting the heat exchange process between the GHE and ground by promoting the pure conduction to the conjugated convection and conduction heat transfer. In this paper, the variations of the ground temperature field and the thermal influence radii subject to the existence of aquifers were investigated numerically. The geometrical models consisting of a coaxial heat exchanger, multiple aquifer and aquifuge layers were established to study the effect of groundwater velocities and the number of aquifer layers on the GHE system. The results reveal that the heat exchange capacity of the GHE is enhanced when the groundwater velocity increases. The increased number of aquifer layers can also enhance the heat exchange capacity with the tested groundwater velocity at 315 m/a or 31.5 m/a, but would weaken it with the velocity of 3.15 m/a. In addition, it is found that the aquifuge temperature field is affected by the aquifer layer, and the thermal influence radius of GHE is dominated by the groudwater velocity of aquifers when the velocity is larger than the critical velocity. Conversely, the thermal influence radius is governed by the thermal diffusivities of aquifuges for the groundwater velocity samller than the critical velocity.
Experimental validation and improvement of actuator line model in the large-eddy simulation of wind-turbine wakes
Authors: Gao Zhi-Teng , Wang Tong-Guang 
Published: April 2020

Abstract
Wind-turbine wakes significantly affect the power output of downstream wind turbines. In order to improve the calculation accuracy of wind-turbine wakes in the atmospheric boundary layer, a new improved actuator line - large-eddy simulation (AL-LES) method is proposed and verified by experiments. The traditional AL-LES method is improved in three aspects. Firstly, the atmospheric turbulence is generated by a dynamic k-equation LES with a wall shear stress model and a buoyancy effect model. Secondly, the nacelle and tower are modelled based on the static actuator line method. Finally, the distribution of blade body force is improved by using an anisotropic 3D Gaussian function. Based on the results of three wind tunnel experiments conducted by Norwegian University of Science and Technology (NTNU), China Aerodynamics Research and Development Centre (CARDC) and Von Karman Institute for Fluid Dynamics (VKI), the improved AL-LES method is validated from the aspects of wind-turbine power performance, the generation of tip vortex, and the distribution of wake velocity under typical offshore and onshore conditions. In addition, a full-scale wind turbine installed in Gansu is used for the experimental and numerical research. The main conclusion is that compared with the traditional method, the new AL-LES method improves the numerical accuracy by nearly 22%, and can more accurately simulate the interaction between atmospheric turbulence and wind-turbine wakes. The results can help the research of wind-turbine wakes and the micro-location selection of wind farm.
On the performance of melting features in a thermal energy storage unit: metal foam argumentation
Authors: Yang Xiaohu , Niu Zhaoyang , Yu Jiabang , Liu Gang , Wang Xuanbo , Zhao Mengyu , Yu Xiyang 
Published: April 2020

Abstract
Thermal energy storage has been attracting more and more attentions due mainly to its distinctive features on peak-load shifting capability for systems with renewable energy involved. To further improve the overall thermal efficiency for charging/discharging processes, heat transfer techniques to enhance phase change heat transfer are typically employed. This paper introduced a novel concept of partially-filling ratio of metal foam into PCM. The melting heat transfer can be expected to be further enhanced with partially filled metal foams. To this aim, an axisymmetric two-dimensional computational model was established. A series of numerical simulations were carried out to study the effect of filling ratio of metal foam on the melting performance of a TES tube. Good agreement was achieved through the comparison of temperatures obtained from simulation and experimental measurements. Based on the results, it can be concluded as follows: if the goal was to enhance heat transfer simultaneously to save material cost, the suggested filling ratio was 0.90; if saving material cost was the aim, the filling ratio can be further reduced to 0.85. The proposed novel TES unit with partially-filled metal foam outperformed other competing heat transfer technique.
Three-phase five level diode clamped inverter for AC load interfacing in DC Microgrid
Authors: Win Soe , Linn Zarchi 
Published: April 2020

Abstract
In this paper, diode clamped type three-phase five-level inverter is used for AC load interfacing in DC microgrid. Multilevel inverters generate staircase voltage waveform with a series of power semiconductor switches from several layer voltage DC sources. Therefore, the output voltage waveforms in multilevel inverters can be generated at low switching frequency with high efficiency and low distortion. In two-level inverter, various pulse width modulation (PWM) strategies with high switching frequency is required to obtain a output voltage or a current waveform with a small amount of harmonic content. In existing DC microgrid, three-phase conventional two-level Sine-PWM inverter is used and so, total harmonic distortion (THD) is high. To reduce the THD and the size of AC filter and to get the quality output, diode clamped type three-phase five-level inverter is applied in this research. Level shift multi carrier Sine-PWM method is used for the diode clamped circuit topology. The output waveforms of conventional two-level inverter and diode clamped five-level inverter are measured and compared the each output waveform qualities such as voltage THD, current THD and AC filter size. The performance of five level diode clamped inverter is illustrated by PSIM software and experimental results are carried out with prototype.
Smart solar photovoltaic panel cleaning system
Authors: Khadka Nasib , Bista Aayush , Adhikari Binamra , Shrestha Ashish , Bista Diwakar 
Published: April 2020

Abstract
With the increasing demand for renewable energy, solar photovoltaic technology is being a topic of concern. However, due to the accumulation of dust and dirt over the panel surface, the performance of the photovoltaic system degrades to a noticeable number. To address this issue: a fully automated, cost worthy and efficient system needs to be invented. This paper presents the design and fabrication process of a prototype able to clean the panel surface. The prototype of this system comprises of a cleaning robot and a cloud interface: the cleaning robot is mobile and able to clean the entire solar array back and forth, with its separately driven cleaning rotatory brush; whereas, the cloud interface is a human-machine interface featuring the distant monitoring and control of the robot. Additionally, to notify the performance of distantly placed solar farm, a sensing unit consisting of sensors was added to this system. Furthermore, to add an automatic cleaning feature, a month-long data of totally clean and dusty panel was processed with regression analysis, and the developed regression model was programmed into the sensing unit. The sensing unit added with the regression model is named as an autonomous unit, as it predicts the suitable time for cleaning action. According to the system evaluation done on a demonstration PV module, it was found that the designed system can clean dry dust accumulated over the panel’s surface. Moreover, by attaching the metal rail tracks on a long solar array, the system seems to be implementable on a large scale solar farm.
Effect of surfactants on thermal conductivity of graphene based hybrid nanofluid
Authors: Hong W.X. , Sidik N.A.C. , Saidur R. 
Published: April 2020

Abstract
Various hybrid nanofluids have been researched in this decade. The quality of this said-to-be alternate heat transfer medium depends on two major features – long term stability and high thermal conductivity. In recent years, graphene-based nanofluid was reported to exhibit distinguished heat transfer performance compared to most materials investigated in past studies. This study aims to compare the effect of different surfactants on thermal conductivity of graphene-based nanofluid. Sodium dodecylbenzenesulfonate (SDBS) and hexadecyltrimethylammonium bromide (CTAB) were mixed separately in advance with the mixture of water and ethylene glycol. After mixing surfactants and base fluid, total 0.025 to 0.1 wt% of nanoparticles were added into the mixture and followed by ultrasonication. Mono nanofluid was produced by adding graphene nanoplatelets (GnP) only whereas a novel hybrid combination was composed of graphene nanoplatelets and titanium dioxide. Stability of each sample was inspected using zeta potential analysis and Uv-vis spectroscopy. Thermal conductivity of samples from 30 °C to 60 °C was measured using Decagon KD2 Pro. Both surfactants contributed to high zeta potential value and minimal sedimentation for all nanofluids. CTAB improved the thermal conductivity of hybrid nanofluid more compared to SDBS, with 11.72% difference at 0.1 wt% nanoparticles concentration when compared to base fluid at 60 °C. The highest enhancement (23.74%) on base fluid was spotted at 60 °C, where 0.1 wt% of GnP was mixed with CTAB. These findings could strengthen literature on suitable surfactant to be used on graphene based nanofluid since limited comparison work has been done. High thermal conductivity of the hybrid nanofluid at high temperature could be used as coolant in cooling system.
Business model and market designs for solar prosumer on peer to peer energy trading in Thailand
Authors: Kokchang P. , Junlakarn S , Audomvongseree K. 
Published: April 2020

Abstract
In recent years the power system is undergoing a rapid change from the traditional power system with large-scale power plants to small-scale distributed generations such as wind energy and solar photovoltaic system. In addition, the technology related to the electric business has been developed rapidly, such as solar power development technology, energy storage, and various communication and measurement devices, etc. The development of these technologies together with the reduced cost of technologies is the main factor in the transformation of the electric business model in many countries around the world, including Thailand to the way that electricity users turn from being consumers only to be both consumers and producers of electricity or called as prosumers. Also, it drives to the new paradigm: peer-to-peer electricity trading, where consumers and prosumers can buy or sell electricity locally. However, the concept of peer to peer energy trading is at early stage in Thailand. This study points out the benefits and barriers of peer to peer energy market based on reviewed existing peer to peer energy projects worldwide. The results of study show that the major regulatory barriers that restrictive to peer to peer market in most countries are the licensed energy supplier issue, network charging and no excess generation is fed back into the national grid.
Numerical investigation on melting of various nanoparticles enhanced phase change material inside a square enclosure
Authors: Kean Tung Hao , Che Sidik Nor Azwadi 
Published: April 2020

Abstract
In this paper, the numerical simulation on melting of phase change material was run by using ANSYS Workbench 17.0 that included mesh generation tools and FLUENT software. Paraffin wax was selected as the PCM and three types of nanoparticles: Alumina (Al2O3), Copper oxide (CuO) and Zinc Oxide (ZnO) were added to form nanoparticles enhanced phase change material. This paper focus on the melting rate and energy stored of phase change material in a 100mm × 100mm square enclosure. The effect of heat source orientation and the mass fraction of nanoparticles dispersed in phase change material were also investigated. Enthalpy porosity method was applied in this numerical study. Results shown that melting rate only can improved by adding low volume fraction of nanoparticles (2% wt). The overall melting rate of phase change material heated from the vertical side is higher than that heated from below. Besides, the energy Stored during the melting of phase change material heated from vertical side is greater and faster compared with heated from bottom. Al2O3 was the best enhancing nanomaterial among those three nanoparticles as it shown the fastest melting rate and highest amount of energy stored (207287 J).
A review on preparation of nanocellulose for new green working fluid in heat transfer application
Authors: Bin Harun Muhammad Arif , Che Sidik Nor Azwadi 
Published: April 2020

Abstract
Cellulose is one of the sustainable raw materials and natural polymers as it can be abundantly found in biomass products. Nanocellulose consist of three categories which are bacterial nanocellulose (BNC), cellulose nanofibrils (CNF), and cellulose nanocrystalline (CNC) has the potential to be used for working fluid in heat transfer application with nanofluid characteristics. Nanofluid is defined as a fluid that has nanoparticle dispersed in it. This nanoparticle will enhance the thermophysical properties of the base fluid. Many types of nanofluid have been used widely in heat transfer applications such as Al2O3, TiO2, CuO and CNT but only a few studies had been done using green and environmentally friendly materials. Therefore, nanocellulose is one of the best candidates as one of the nanofluid’s materials which has green and environmentally friendly properties. The preparation of nanofluid is very crucial because improper preparation will lead to deterioration of nanofluid and decrease the thermal performance as heat transfer working fluid. Other than that, low stability cause nanoparticle to form clusters and sediment due to its strong van der Waals interaction. Therefore, this study will focus on the preparation method of the nanocellulose for heat transfer application. Other than that, methods of stability analysis for nanocellulose also presented in this paper.