bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-Objective Optimization for Combined Heat Power Operations considering Flexibility, Costs and Environmental Emissions
Authors: Wei Jen Lok , Yin Ng Lik , Andiappan Viknesh 
Published: May 2020

Abstract
Optimal operation of a combined heat and power (CHP) system proves to be a challenge. This is because CHP systems could be operated in several alternative configurations. In fact, each technology may have different heat and electricity outputs, costs, emissions and flexibilities. To address such challenge, operational optimization must be considered. In this paper, a mathematical optimization model was developed to optimise cost, carbon dioxide emissions and flexibility for a CHP system operation to meet increased energy production requirements. The developed model employs multi-objective optimization to determine a trade-off between costs, carbon dioxide emissions and flexibility. To demonstrate the proposed approach, a multi-fuel CHP case study was solved. Results indicate that a trade-off CHP configuration that achieves the best possible balance between costs, emissions and flexibility was determined.
Optimization of methanol production via CO2 hydrogenation: comparison of sampling techniques for process modeling
Authors: Borisut P , Nuchitprasittichai A 
Published: May 2020

Abstract
This paper compares performances of three different sampling techniques in representing nonlinear response surface for optimization problem, with five decision variables. Three studied sampling techniques are Central Composite Design (CCD), Box – Behnken Design (BBD) and Latin Hypercube Sampling ( LHS). Simulation – based optimization of methanol production via CO2 hydrogenation process was used as a case study. The objective of this optimization problem is to minimize the methanol production cost. The nonlinear model ( the objective function) represents the relationship between operating conditions and methanol production cost. The results show that the response surface of this case study is trend to be the third order model ( with R – squared value greater than 0.97) for all sampling techniques. BBD is the most suitable sampling technique in this study, resulting in the percent error less than 1.2. The LHS shows comparable performance with BBD if it has suitable number of sample points.
Impact of biomass upgrading via hydrothermal treatment on slagging and fouling during cofiring with coal
Authors: Yan Mi , Ar Rahim Dicka , Susanto Herri , Dennie Agustin Pohan Rahmad , Hantoko Dwi 
Published: May 2020

Abstract
Palm oil empty fruit bunch (EFB) is a by-product produced during palm oil processing. In South East Asian countries, EFB is abundant and can be utilized as a renewable energy source. Cofiring of EFB with coal can be beneficial for preserving coal and reducing CO2 emission. However, EFB has some weaknesses in its properties such as; low bulk density, high moisture content, high alkaline contents, etc. Moreover, high amount of silicon and potassium in EFB tend to increase ash agglomeration which causes slagging and fouling in the equipment. In this study, hydrothermal treatment (HT) was employed to improve the physicochemical properties of the EFB by turning into biochar. Biochars are obtained after EFB is treated hydrothermally at a temperature range of 200-300 oC for 60 minutes were characterized for their proximate and ultimate compositions, mineral composition, calorific values, and ash fusion temperature. The analyses showed that fixed carbon increased while volatile matter decreased after HT. These changes were more prominent with increasing reaction temperature. The calorific values of EFB increased from 19.05 MJ/kg to 29.31 MJ/kg after HT at 300 oC. The biochar was then mixed with coal at different ratios (1:1, 1:2, and 2:1) for cofiring. The results showed that the energy densification increased with increasing reaction temperature. XRF results showed that the contents of Na, K and Si in EFB decreased after HT, resulting in the increased ash melting temperature. Consequently, the fouling and agglomeration potential could be reduced. The optimum ratio for cofiring between biochar and coal was found to be 2:1, as the fouling and slagging indices were lowest. It can be concluded that HT is a promising method for upgrading EFB as a feedstock for cofiring with coal.
Effect of glucose concentration and cultivation days on Chlorella vulgaris growth via immobilization technique for biodiesel production
Authors: Abu Sepian N R , Mat Yasin N H , Zainol N 
Published: May 2020

Abstract
Immobilization technique had been utilized to simplify the separation process of microalgae biomass for biodiesel production in the present study. The optimization using response surface methodology (RSM) through central composite design (CCD) approach had been applied to maximize the number of cells growth and minimized the cells loss of Chlorella vulgaris cells via immobilization technique. Two effects were optimized by CCD consisting of glucose concentration and cultivation days. The glucose concentration at 23.99 g/L and 7.96 days of cultivation time were found to be the optimum conditions for the maximum number of cells growth (3.30 × 109 cells/mL) and a minimum number of cells lost (1.07 × 104 cells/mL). The optimization using CCD had increased the lipid to 51.6 % and the result of fatty acid methyl ester (FAME) profile is similar to non-bearing oil crop. The findings had revealed the potential of immobilized microalgae biomass as an alternative feedstock for biodiesel production. Moreover, this study had reported optimum conditions for an efficient recovery process via immobilization technique using mixed matrices.
Kinetic analysis of co-pyrolysis of biomass/sorbent mixtures at different ratios
Authors: Ariffen A R , Yusoff N 
Published: May 2020

Abstract
Biomass is one of the most promising sources of renewable energy. Gasification of carbonaceous and lignocellulosic biomasses produces gases, which can be upgraded as a clean feedstock for power plants. However, control and optimization of industrial gasification is still a challenging task due to a lack of understanding in solid state reaction mechanisms. This work attempts to improve kinetic modelling of a gasification process through analyses of four locally available biomasses, namely, oil palm trunk, fronds, empty fruit bunches, and coconut fibre. The biomasses were mixed with sorbents to enhance the pyrolysis and gasification reaction in a thermogravimetric analyser. In addition to common sorbents such as oxides of magnesium and calcium, two other sorbents, namely, rice husk and eggshell (a source of calcium carbonate) were blended at different ratios of biomasses to investigate their behaviour under pyrolytic decomposition conditions. Activation energies of the mixtures were obtained with the Reaction Rate Constant Model (RRCM). It was found that the mixtures had higher activation energies as compared to pure biomasses. For example, oil palm trunk without sorbent and with 50 wt% calcium oxide had activation energies of 26.87 and 46.83 kJ/mol, respectively. Majority of the sorbents also increased the thermal stability of the biomasses by increasing the mixtures’ resistance to weight loss under high temperature. However, rice husk reduced the mixtures’ thermal stability when compared with pure biomasses as evident in the oil palm trunk case when the mixture became 6.2% less thermally stable.
A comparison of the acid mine drainage (AMD) neutralization potential of low grade nickel laterite and other alkaline-generating materials
Authors: Turingan C. , Singson G. , Melchor B. , Alorro R. , Beltran A. , Orbecido A. 
Published: May 2020

Abstract
Acid mine drainage (AMD) is a serious environmental problem caused by the weathering of sulfur-rich minerals found in mine sites, typically pyrite. Passive treatment methods have been extensively studied exploring various materials and treatment systems. Limestone is typically used as neutralizing media through open channels or anoxic limestone drains. However, the armouring that occurs when heavy metals precipitate on the surface restricts the lifespan of limestone treatment systems to 15-20 years. Goethite has been characterized to be a good adsorbent of heavy metals found in wastewater. It is abundant in a layer of nickel laterite deposit which are considered mine wastes due to the low amount of nickel present. This study investigates the performance of locally available nickel laterite ore rock, limestone, fly ash, and cement waste as media for AMD neutralization. The treatment efficiency are evaluated based on the physiochemical properties of the AMD, namely: pH, redox potential (ORP), conductivity, total dissolved solids (TDS), and dissolved oxygen (DO).
Effect of Coolant Temperature and Stirring Rate in the Separation of Oil from Bilge Water using a Stirred Freeze Crystallizer
Authors: Mustapha S. N. A. , Amran N. A. , Samsuri S. 
Published: May 2020

Abstract
Each year, marine activities has contributed to nearly half of the discharged oil into the oceans, where 10% of it were dumped bilge oil. The tankers release oily and chemical residue, causing pollution to the marine environment due to excessive contamination of bilge water. Therefore, all marine ships over 400 tons are required to install an oil-water separator (OWS) system on board to limit the discharge of oil into the oceans. However, the current OWS technologies such as gravity and centrifugation method have difficulties to comply with the oil/grease discharge standard of 15 mg/L set by Malaysia’s Department of Environment (DOE). This paper aims to introduce progressive freezing (PF) process as a new OWS method where it separates two liquid compounds based on their freezing point difference. One with higher freezing point will solidify first while another one will remain as liquid. In this study, the effect of coolant temperature and stirring rate towards oil/grease values were investigated. It was found that the highest efficiency of the PF process was obtained at stirring rate of 200 rpm and coolant temperature of -6°C. In addition, the best oil/grease value obtained was found to be lower than the discharge standard permitted by the Department of Environment (DOE), Malaysia.
Effect of Biocover Thickness on Methane Oxidation Rate of Landfill Gas Emission from Municipal Solid Waste Landfill in Tropical Climate Region
Authors: Yusnan  , Razi F. , Munawar E. 
Published: May 2020

Abstract
The landfilling of municipal solid waste (MSW) in developing countries mostly is carried out by means of open dumping or control landfills. The degradation of organic compounds of MSW inside the landfill will produce the landfill gas, where the main component is methane (CH4) and carbon dioxide (CO2) are categorized as the greenhouse gas (GHG). These gases if not managed properly will escape and increase the GHG accumulation in the atmosphere. There is many methods has been established and apply to reduce landfill gas emission, but mostly required high investment so not affordable for developing countries. Method that might be applied to reduce GHG emissions from landfill in developing countries is utilization the microorganism to oxidizing CH4 commonly called biocover. The purpose of the study was to analyze the effect of biocover thickness on the oxidation efficiency of CH4 from landfill gas in tropical countries. The concentration CH4 in landfill gas throughout landfill simulator reactor (LSR) covered by 20-60 cm of thick the biocover was measured daily by using the gas analyzer (Sewerin, Multitec 540). The LSR was made of acrylic pipe with a diameter of 25 cm and height of 100 cm. The landfill gas was used has an initial concentration of CH4 approximately 30% and the moisture content of biocover used was maintained at 40%. The experimental results obtained shows the CH4 oxidation efficiency of biocover for 20 cm, 40 cm and 60 cm thick were 8.12%, 9.72% and 4.56%, respectively.
Total phenolic content and antioxidant activity of Pandanus amaryllifolius by soaking and microwave-assisted extraction
Authors: Asyikin Md Zaki Nurul , Abd Hashib Syafiza , Kalthum Ibrahim Ummi , Ani Narisa Ahmad Bakhtiar Putri 
Published: May 2020

Abstract
Many studies have reported on the limitation of conventional extraction methods. Therefore, this work aims to compare the effects of conventional soaking extraction and microwave-assisted extraction (MAE) on the total phenolic content (TPC) and antioxidant activity of Pandanus amaryllifolius leaves. For soaking method, the pandan leaves were soaked in various ethanol-water mixture (50, 75 and 100%) at different temperatures (40, 50, 60, 70°C) for 10 minutes. Meanwhile for MAE method, the pandan leaves were extracted in the same concentrations of ethanol-water and subjected to different microwave power level (100, 180, 300, 450, 600 and 850W) for 10 minutes. It was found that MAE resulted in higher yield of TPC (1.557 mg/g gallic acid equivalent) compared to conventional soaking method (0.979 mg/g gallic acid equivalent). MAE could remarkably retain bioactive total phenolic content and antioxidant activity and has huge potential and application in the food industry.
Estimating species concentration in CO2-loaded monoethanolamine using Raman spectroscopy
Authors: Syukri Na’im Bin Mohd Hanafiah Ahmad , Shah Maulud Abdulhalim 
Published: May 2020

Abstract
Operation of amine plant for CO2 removal had long been plagued with inefficiencies due to suboptimal operating parameter leading to losses in operational expenditure. Improving the system requires understanding into thermodynamics and kinetics of the process which can be made possible through having information on the qualitative and quantitative speciation in the alkanolamine system. In this work, potential of Raman spectroscopy as a monitoring tool for species concentration in CO2-loaded aqueous monoethanolamine (MEA) system was investigated. CO2 loading data from experimental work were used with Kent Eisenberg model to estimate species concentrations (dissolved CO2, Protonated amine, Bicarbonate, Carbonate, Carbamate and unreacted MEA). Each species concentration were fitted to experimentally-acquired Raman spectrum using Partial Least Square Regression (PLSR) technique to develop calibration model. Evaluation of regression plots, R2 and Root Mean Square Error (RMSE) shows good predictive accuracy compared to the thermodynamically-predicted species concentration.
Study of progressive freeze concentration and eutectic freeze crystallization technique for salt recovery
Authors: Mazli W N A , Samsuri S , Amran N A 
Published: May 2020

Abstract
In this industrial era, salt recovery from seawater has become an important issue from the environment perspective. Few freezing technologies have been proposed as capable way to separate the salt from the seawater because of the energy used in the previous technologies is higher. A study of Progressive Freeze Concentration (PFC) and Eutectic Freeze Concentration (EFC) method have been carrying out and further investigated on their performance in recovering the salt. For the PFC method, pure water crystallizes into crystal and the concentrate is left behind as in liquid form while for the EFC method, both ice crystals and salt crystallize at the same time when the initial concentration of water salt mixture is exactly the same as eutectic concentration. In EFC, salt sinks to the bottom while ice floats at the top of the crystallizer and both are separated by gravity separation. Effective partition constant and solute recovery are calculated to evaluate the efficiency of PFC and EFC. In this study, the PFC method has shown an effective partition constant of 0.28 and recovered solute of 0.88 g of sodium chloride per 1 g of initial sodium chloride while for EFC method, effective partition constant and solute recovery obtained are 0.59 and 0.66. Overall, both techniques are applicable for the seawater desalination process.
Study of raw and chemically treated Sansevieria ehrenbergii fibers for brake pad application
Authors: S Senthil Kumaran , Srinivasan Kathiravan , M Ponmariappan , S Yashwhanth , S Akshay , Hu Yuh-Chung 
Published: May 2020

AbstractThe replacement for synthetic fiber and other materials with natural fiber in the brake pad has become a key research area in many industries. Many production industries are always focused on natural fiber over synthetic fibers because of its advantage of biodegradability, less expensive, availability, and environment friendly. However, natural fibers cannot be used directly in composites because of its poor adhesion behavior between matrix and fiber and observe high water content in the fiber. Further, the excess water content in the inside fiber has been removed by using alkaline, benzoylation, and acetylation treatment. It has been achieved by the same chemical concentration but with different time duration. The Fourier-transform infrared spectroscopy (FT-IR) analysis revealed that the amount of cellulose content after chemical treatment was improved and decrease in other substances like hemicellulose, lignin, and wax content. X-Ray Diffraction (XRD) analysis study confirmed that the rise in the crystalline index (70.41 from 52.7) of alkali-treated SEFs at 30 min. The thermogravimetric analysis study has confirmed that the increase in the degradation temperature of Benzoyl-treated SEFs (387 °C) at 60 min when compared with untreated fiber (320 °C). The Scanning Electron Microscope (SEM) results have confirmed that the elimination of impurities from the fiber surface after chemical treatment. Further, the acetyl- treated fibers have shown that better hydrophobic properties than other treated fibers. In the above tests have been concluded that the chemically treated fibers, as one of the suitable materials for the development of the brake pad application.
Effect of sulfuric acid concentration on the quality of copper microcolumns in localized electrochemical deposition
Authors: Qing Qixin , Wang Fuliang 
Published: May 2020

Abstract
Localized electrochemical deposition (LECD) is a promising method for three-dimensional micro-/nanofabrication and, thus, the factors influencing LECD have been intensively investigated. This study examined the effect of sulfuric acid concentration on copper microcolumns deposited by LECD using a microanode with a diameter of 20 μm. With 0.05 mol l−1 sulfuric acid, the deposition voltage of the optimal deposited morphology of copper microcolumns was at 2.9 V, but the column diameter was larger than the anode diameter. With 0.5 and 2.0 mol l−1 sulfuric acid, the optimal deposited morphology of copper microcolumns were at 3.2 V and 3.4 V, respectively, but the diameters of the copper microcolumns were smaller than the anode diameter. In the LECD process, the deposition rate is proportional to the deposition voltage. Because of the hydrogen evolution, the deposition rates of copper microcolumns at high sulfuric acid concentration were lower than those at low and medium sulfuric acid concentrations. The results of this study indicated that the deposition rate obtained the optimal surface topography was 0.22 to 0.327 um s−1, which had reference significance to improve the quality of the copper microcolumns. The effect of sulfuric acid on the LECD was demonstrated using a competitive reduction mechanism.
A novel privacy-preserving federated genome-wide association study framework and its application in identifying potential risk variants in ankylosing spondylitis
Authors: Wu Xin , Zheng Hao , Dou Zuochao , Chen Feng , Deng Jieren , Chen Xiang , Xu Shengqian , Gao Guanmin , Li Mengmeng , Wang Zhen , Xiao Yuhui , Xie Kang , Wang Shuang , Xu Huji 
Published: May 2020

AbstractGenome-wide association studies (GWAS) have been widely used for identifying potential risk variants in various diseases. A statistically meaningful GWAS typically requires a large sample size to detect disease-associated single nucleotide polymorphisms (SNPs). However, a single institution usually only possesses a limited number of samples. Therefore, cross-institutional partnerships are required to increase sample size and statistical power. However, cross-institutional partnerships offer significant challenges, a major one being data privacy. For example, the privacy awareness of people, the impact of data privacy leakages and the privacy-related risks are becoming increasingly important, while there is no de-identification standard available to safeguard genomic data sharing. In this paper, we introduce a novel privacy-preserving federated GWAS framework (iPRIVATES). Equipped with privacy-preserving federated analysis, iPRIVATES enables multiple institutions to jointly perform GWAS analysis without leaking patient-level genotyping data. Only aggregated local statistics are exchanged within the study network. In addition, we evaluate the performance of iPRIVATES through both simulated data and a real-world application for identifying potential risk variants in ankylosing spondylitis (AS). The experimental results showed that the strongest signal of AS-associated SNPs reside mostly around the human leukocyte antigen (HLA) regions. The proposed iPRIVATES framework achieved equivalent results as traditional centralized implementation, demonstrating its great potential in driving collaborative genomic research for different diseases while preserving data privacy.
Prokineticin 1–prokineticin receptor 1 signaling promotes angiogenesis in the porcine endometrium during pregnancy†
Authors: Goryszewska Ewelina , Kaczynski Piotr , Balboni Gianfranco , Waclawik Agnieszka 
Published: May 2020

Abstract
Pregnancy establishment in mammals, including pigs, requires proper communication between embryos and the maternal reproductive tract. Prokineticin 1 (PROK1) has been described as a secretory protein with pleiotropic functions and as a novel tissue-specific angiogenic factor. However, despite the studies performed mainly on human cell lines and in mice, the function of PROK1 in the endometrium during early pregnancy is still not fully elucidated. We hypothesized that PROK1 contributes to pregnancy establishment in pigs. The present study is the first to report that the expression of PROK1 and its receptor (PROKR1) is elevated in the porcine endometrium during the implantation and early placentation period. PROK1 protein was detected mainly in luminal epithelial cells, glandular epithelial cells, and blood vessels in the endometrium. Using the porcine in vivo model of unilateral pregnancy, we revealed that conceptuses induced the endometrial expression of PROK1 and PROKR1. Moreover, the embryonic signal, estradiol-17β, as well as progesterone, stimulated the endometrial expression of PROK1 and PROKR1. We also evidenced that PROK1–PROKR1 signaling supports endometrial angiogenesis in pigs. The PROK1-stimulated proliferation of primary porcine endometrial endothelial (PEE) cells involved PI3K/AKT/mTOR, MAPK, cAMP, and NFKB signaling pathways. Furthermore, PROK1 via PROKR1 promoted the formation of capillary-like structures by PEE cells. PROK1 also stimulated VEGFA and PGF2α secretion, which in turn may indirectly support angiogenic changes within endometrial tissue. In summary, our study suggests that PROK1 acts as an embryonic signal mediator that regulates endometrial angiogenesis and secretory function during the implantation and early placentation period in pigs.