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Records Added in September 2019
Records added in September 2019
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Showing records 78 to 102 of 102. [First] Page: 1 2 3 4 5 Last
Innovative Effluent Capture and Evacuation Device that Increases COD Removal Efficiency in Subsurface Flow Wetlands
Pedro Cisterna-Osorio, Verónica Lazcano-Castro, Gisela Silva-Vasquez, Mauricio Llanos-Baeza, Ignacio Fuentes-Ortega
September 13, 2019 (v1)
Keywords: artificial wetlands, horizontal wetland, subsurface flow
The objective of this work is to evaluate the impact of innovative modifications made to conventional effluent capture and discharge devices used in subsurface flow wetlands (SSFW). The main modifications that have been developed extend the influence of the capture and discharge device in such a way that the SSFW width and height are fully covered. This improved innovative device was applied and evaluated in two subsurface flow wetlands, one on a pilot scale and one on a real scale. To evaluate the impact of the innovative device with respect to the conventional one in the operational functioning of subsurface flow wetlands, the elimination of chemical oxygen demand (COD) was measured and compared. The results show that for the innovative device, the COD removal was 10% higher than for the conventional device, confirming the validity and effectiveness of the modifications implemented in the effluent capture and discharge devices used in SSFW.
Curcumin Analogues with Aldose Reductase Inhibitory Activity: Synthesis, Biological Evaluation, and Molecular Docking
Dasharath Kondhare, Sushma Deshmukh, Harshad Lade
September 13, 2019 (v1)
Subject: Biosystems
Keywords: aldose reductase inhibitor, antidiabetic, Claisen–Schmidt condensation, curcumin analogues, molecular docking
Curcumin, a constituent of Curcuma longa, has shown numerous biological and pharmacological activities, including antidiabetic effects. Here, a novel series of curcumin analogues were synthesized and evaluated for in vitro inhibition of aldose reductase (AR), the first and rate-limiting enzyme of the polyol pathway, which plays a key role in the onset and progression of diabetic complications. Biological activity studies showed that all the curcuminoids exhibited moderate to good AR inhibitory (ARI) activities compared with that of the quercetin standard. Importantly, compounds 8d, 8h, 9c, 9e, and 10g demonstrated promising ARI activities, with the 50% inhibitory concentration (IC50) values of 5.73, 5.95, 5.11, 5.78, and 5.10 µM, respectively. Four other compounds exhibited IC50 values in the range of 6.04−6.18 µM. Methyl and methoxy derivatives showed a remarkable ARI potential compared with that of other substitutions on the aromatic ring. Molecular docking experiments demonstrated t... [more]
Natural Deep Eutectic Solvent-Assisted Pectin Extraction from Pomelo Peel Using Sonoreactor: Experimental Optimization Approach
Amal A. M. Elgharbawy, Adeeb Hayyan, Maan Hayyan, Mohamed E. S. Mirghani, Hamzah Mohd. Salleh, Shahidah Nusailah Rashid, Gek Cheng Ngoh, Shan Qin Liew, Mohd Roslan Mohd Nor, Mohd Yakub Zulkifli bin Mohd Yusoff, Yatimah Alias
September 13, 2019 (v1)
Subject: Biosystems
Keywords: Citrus grandis, definitive screening design, Extraction, natural deep eutectic solvent, pectin, pomelo
Background: Natural deep eutectic solvents (NADESs) can be used for extracting a wide range of biomaterials, such as pectin. This study introduces a new generation of natural solvents for pectin extraction which could replace the conventional solvents in the food industry. Methods: In this study, NADESs were used for pectin extraction from pomelo (Citrus grandis (L.) Osbeck) peels using a sonoreactor. Definitive screening design (DSD) was used to screen the influence of time, temperature, solid/liquid ratio, and NADES/water ratio on the pectin yield and degree of esterification (DE). Results: The primary screening revealed that the best choices for the extraction were choline chloride−malonic acid (ChCl-Mal) and choline chloride−glucose−water (ChCl:Glc:W). Both co-solvents yielded 94% pectin and 52% DE after optimization at 80 °C, with 60 min of sonication, pH < 3.0, and a NADES-to-water ratio of 1:4.5 (v/v). Morphological screening showed a smooth and compact surface of the pectin fro... [more]
Gain Scheduling of a Robust Setpoint Tracking Disturbance Rejection and Aggressiveness Controller for a Nonlinear Process
Veeramani Bagyaveereswaran, Pachiyappan Arulmozhivarman
September 13, 2019 (v1)
Keywords: controller, gain scheduling, Optimization, performance criteria, PID, regulatory, servo
In this paper, a robust setpoint tracking disturbance rejection and aggressiveness (RTD-A) controller is designed and developed to control the liquid level of a conical tank process. Meta-heuristic algorithms like grey wolf optimization and the genetic algorithm are used to tune the parameters of the RTD-A controller. Its performance is later compared with that of the conventional standard proportional integral derivative controller. The gain scheduled RTD-A controller is designed and implemented on a nonlinear conical tank process. Also, various performances attributes such as the integral square error, integral absolute error, integral time absolute error, rise time, and settling time are calculated for the first-order process and conical tank process. The servo responses with RTD-A are also compared against the responses recorded from the conventional control schemes.
Fabrication of Green Superhydrophobic/Superoleophilic Wood Flour for Efficient Oil Separation from Water
Xuefei Tan, Deli Zang, Haiqun Qi, Feng Liu, Guoliang Cao, Shih-Hsin Ho
September 13, 2019 (v1)
Subject: Biosystems
Keywords: oil adsorption, oil-water separation, superhydrophobic, superoleophilic, sustainable material, wood flour
The removal of oil from waste water is gaining increasing attention. In this study, a novel synthesis method of green superhydrophobic/superoleophilic wood flour is proposed using the deposition of nano−zinc oxide (nZnO) aggregated on the fiber surface and the subsequent hydrophobic modification of octadecanoic acid. The as-prepared wood flour displayed great superhydrophobicity and synchronous superoleophilicity properties with the water contact angle (WCA) of 156° and oil contact angle (OCA) of 0° for diesel oil. Furthermore, the as-prepared wood flour possessed an excellent stability, probably due to the strong adhesion of nZnO, which aggregates to the fiber surface of wood flour with the action of glutinous polystyrene. The maximum adsorption capacity of as-prepared wood flour was 20.81 g/g for engine oil, which showed that the as-prepared wood flour is a potential candidate as an efficient oil adsorbent in the field of water-oil separation. Moreover, it has good chemical steadines... [more]
Irregularity Molecular Descriptors of Hourglass, Jagged-Rectangle, and Triangular Benzenoid Systems
Zafar Hussain, Shazia Rafique, Mobeen Munir, Muhammad Athar, Maqbool Chaudhary, Haseeb Ahmad, Shin Min Kang
September 13, 2019 (v1)
Subject: Materials
Keywords: benzenoid systems, complexity of structure, hourglass benzenoid system, irregularity measures
Determining the degree of irregularity of a certain molecular structure or a network has been a key source of interest for molecular topologists, but it is also important as it provides an insight into the key features used to guess properties of the structures. In this article, we are interested in formulating closed forms of irregularity measures of some popular benzenoid systems, such as hourglass H (m, n), jagged-rectangular J (m, n), and triangular benzenoid T (m, n) systems. We also compared our results graphically and concluded which benzenoid system among the above listed is more irregular than the others.
Selective Cesium Adsorptive Removal on Using Crosslinked Tea Leaves
Dan Yu, Shintaro Morisada, Hidetaka Kawakita, Keisuke Ohto, Katsutoshi Inoue, Ximing Song, Guolin Zhang
September 13, 2019 (v1)
Keywords: adsorptive removal, biomass wastes, cesium selectivity, ion-exchange
To remove the radioactive cesium from the polluted environment, tea leaves were chosen as cheap, and abundantly available environment-friendly bio-adsorbents to investigate the alkali metals adsorption. Fresh and used tea leaves (FT and UT) were found to have high efficiency and selectivity for cesium adsorption, after the crosslinking with concentrated sulfuric acid. Calculation of the proton-exchanged amount suggested adsorption mechanism of three alkali metals on crosslinked tea leaves involve a cationic exchange with a proton from the hydroxyl groups of the crosslinked tea leaves, as well as coordination with ethereal oxygen atoms to form the chelation. Further, considering the practical application of the polluted water treatment, the competitive adsorption of Cs+ and Na+ ions was investigated by the batch-wise method and column chromatography separation. Unlike the conventional ion exchange and chelate resins with less selectivity for Cs+ coexisting cations, both crosslinked fres... [more]
Statistical Process Monitoring of the Tennessee Eastman Process Using Parallel Autoassociative Neural Networks and a Large Dataset
Seongmin Heo, Jay H. Lee
September 13, 2019 (v1)
Keywords: autoassociative neural network, Big Data, nonlinear principal component analysis, parallel neural networks, process monitoring
In this article, the statistical process monitoring problem of the Tennessee Eastman process is considered using deep learning techniques. This work is motivated by three limitations of the existing works for such problem. First, although deep learning has been used for process monitoring extensively, in the majority of the existing works, the neural networks were trained in a supervised manner assuming that the normal/fault labels were available. However, this is not always the case in real applications. Thus, in this work, autoassociative neural networks are used, which are trained in an unsupervised fashion. Another limitation is that the typical dataset used for the monitoring of the Tennessee Eastman process is comprised of just a small number of data samples, which can be highly limiting for deep learning. The dataset used in this work is 500-times larger than the typically-used dataset and is large enough for deep learning. Lastly, an alternative neural network architecture, whi... [more]
Improvement of 1,3-Butadiene Separation in 2,3-Butanediol Dehydration Using Extractive Distillation
Daesung Song, Young-Gak Yoon, Seung-Kwon Seo, Chul-Jin Lee
September 5, 2019 (v1)
Keywords: 1-butene, 1,3-butadiene, 2,3-butanediol dehydration, Distillation, economic feasibility, extractive distillation
This study was performed to investigate the extractive distillation for 1,3-butadiene (1,3-BD) purification as a part of the 2,3-butanediol (2,3-BDO) dehydration process. The separation of 1,3-BD from 1-butene produced as a 2,3-BDO dehydration by-product while using distillation is complicated due to the similar volatilities of the two compounds. Thus, an extractive distillation system is proposed for the effective recovery of 1,3-BD, and is compared with a conventional distillation system in terms of its performance and economic feasibility. A higher 1,3-BD recovery rate was achieved while using the proposed system and the relative profitabilities of both separation systems were analyzed according to the market price of 1,3-BD, which is a decisive variable for economic feasibility.
Process Simulation of the Separation of Aqueous Acetonitrile Solution by Pressure Swing Distillation
Jing Li, Keliang Wang, Minglei Lian, Zhi Li, Tingzhao Du
September 5, 2019 (v1)
Keywords: acetonitrile, full-heat integration, pressure swing distillation, Water
The separation of aqueous acetonitrile solution by pressure swing distillation (PSD) was simulated and optimized through Aspen Plus software. The distillation sequence of the low pressure column (LPC) and high pressure column (HPC) was determined with a phase diagram. The pressures of the two columns were set to 1 and 4 atm, respectively. Total annual cost (TAC) was considered as the objective function, and design variables, such as the tray number, the reflux ratio, and the feeding position, were optimized. The optimum process parameters were obtained. For the reduction of energy consumption, the PSD with full-heat integration was designed. The TAC of this method is lower by 32.39% of that of the PSD without heat integration. Therefore, it is more economical to separate acetonitrile and water mixture by PSD with full-heat integration, which provides technical support for the separation design of such azeotropes.
Spatial Variations of Bacterial Communities of an Anaerobic Lagoon-Type Biodigester Fed with Dairy Manure
Marleny García-Lozano, Inty Omar Hernández-De Lira, David H. Huber, Nagamani Balagurusamy
September 5, 2019 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, bacterial communities, biodigester, PICRUSt, spatial variations
Anaerobic digestion technology is being widely employed for sustainable management of organic wastes generated in animal farms, industries, etc. Nevertheless, biodigester microbiome is still considered a “black box” because it is regulated by different physico-chemical and operational factors. In this study, the bacterial diversity and composition in different sites of a full-scale lagoon type biodigester (23,000 m3) fed with dairy manure, viz., the influent, beginning, middle, final and effluent were analyzed. The biodigester registered a total of 1445 OTUs, which demonstrated the complex microbial ecosystem in it. Of them, only six OTUs were shared among all the different sampling points. The most abundant phyla belonged to Firmicutes, Proteobacteria, Latescibacteria and Thermotogae. The Simpson and Shannon index showed that the highest microbial diversity was observed in the beginning point of the biodigester, meanwhile, the lowest diversity was recorded in the middle. Based on the... [more]
Control Strategy for Inverter Air Conditioners under Demand Response
Yanbo Che, Jianxiong Yang, Yuancheng Zhao, Siyuan Xue
September 5, 2019 (v1)
Keywords: demand response, inverter air conditioner, virtual energy storage, virtual state of charge
Air conditioning loads are important resources for demand response. With the help of thermal energy storage capacity, they can reduce peak load, improve the reliability of power grid operations, and enhance the emergency capacity of a power grid, without affecting the comfort of the users. In this paper, a virtual energy storage model for inverter air conditioning loads, which reflects their operating characteristics and is more conducive to practical application, is established. Two parts are involved in the virtual energy storage model: An electrical parameter part, based on the operating characteristics, and a thermal parameter part, based on the equivalent thermal parameter model. The control function and restrictive conditions of the virtual energy storage are analyzed and a control strategy, based on virtual state-of-charge ranking, is proposed. The strategy controls the inverter air conditioners through re-assigning indoor temperature set-points within the pre-agreed protocol in... [more]
Removal of Lead and Cadmium Ions from Aqueous Solution by Adsorption on a Low-Cost Phragmites Biomass
Abdulaziz N. Amro, Mohammad K. Abhary, Muhammad Mansoor Shaikh, Samah Ali
September 5, 2019 (v1)
Subject: Materials
Keywords: cadmium, Freundlich isotherm, kinetic study, Langmuir isotherm, lead, treated phragmites biomass
In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer−Emmett−Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb+2 and Cd+2 metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb+2 and Cd+2 respectively to reach equilibrium when 0.10 g TPB was used. The optim... [more]
CO2 Hydrogenation to Methanol by a Liquid-Phase Process with Alcoholic Solvents: A Techno-Economic Analysis
Harri Nieminen, Arto Laari, Tuomas Koiranen
September 5, 2019 (v1)
Keywords: alcohol promoted, CO2 hydrogenation, liquid-phase process, methanol synthesis, process simulation, Technoeconomic Analysis
Synthesis of methanol from recirculated CO2 and H2 produced by water electrolysis allows sustainable production of fuels and chemical storage of energy. Production of renewable methanol has, however, not achieved commercial breakthrough, and novel methods to improve economic feasibility are needed. One possibility is to alter the reaction route to methanol using catalytic alcoholic solvents, which makes the process possible at lower reaction temperatures. To estimate the techno-economic potential of this approach, the feasibilities of the conventional gas-phase process and an alternative liquid-phase process employing 2-butanol or 1-butanol solvents were compared by means of flowsheet modelling and economic analysis. As a result, it was found that despite improved methanol yield, the presence of solvent adds complexity to the process and increases separation costs due to the high volatility of the alcohols and formation of azeotropes. Hydrogen, produced from wind electricity, was the m... [more]
Enhanced Anaerobic Mixed Culture Fermentation with Anion-Exchange Resin for Caproate Production
Jiangnan Yu, Jialin Liao, Zhenxing Huang, Peng Wu, Mingxing Zhao, Chunmei Liu, Wenquan Ruan
September 5, 2019 (v1)
Subject: Biosystems
Keywords: adsorption process, anaerobic mixed culture, caproate fermentation, enhanced performance
The bioproduction of caproate from organic waste by anaerobic mixed culture is a very attractive technology for upgrading low-grade biomass to a high-value resource. However, the caproate production process is markedly restricted by the feedback inhibition of caproate. In this study, four types of anion-exchange resin were investigated for their enhancing capability in caproate fermentation of anaerobic mixed culture. The strong base anion-exchange resin D201 showed the highest adsorption capacity (62 mg/g), selectivity (7.50), and desorption efficiency (88.2%) for caproate among the test resins. Subsequently, the optimal desorption temperature and NaOH concentration of eluent for D201 were determined. The adsorption and desorption efficiency of D201 remained stable during eight rounds of the adsorption−desorption cycle, indicating a satisfactory reusability of D201. Finally, performances of caproate fermentation with and without resin adsorption for carboxylate were evaluated. The res... [more]
Coffee Pulp: A Sustainable Alternative Removal of Cr (VI) in Wastewaters
Dora Luz Gómez Aguilar, Juan Pablo Rodríguez Miranda, Javier Andrés Esteban Muñoz, Jhon Fredy Betancur P.
September 5, 2019 (v1)
Keywords: agricultural residues, coffee pulp (CP), heavy metals, hexavalent chromium, industrial wastewater (IWW), plantain pseudo stem (PP), Sustainable Development Goals (SDG)
Currently, agricultural waste is proposed as a sustainable alternative in the removal of heavy metals present in industrial wastewater, to fulfill some of the goals proposed in the Sustainable Development Goals stated for the 2030 Agenda, in particular in Sections 3.9 and 6.9. Considering this context, the coffee pulp (Castilla variety) of Caldas municipality (Colombia) was used in study for the removal of one of the most toxic chemical species of chromium: Cr (VI). Therefore, the agricultural residue was subjected to a bromatological characterization, determination of the lignocellulosic composition and elucidation of characteristic organic functional groups by IR spectrophotometry. Additionally, the optimal parameters for contaminant removal were identified, regarding particle size, biomass quantity, optimum pH, stirring time, temperature, adsorption kinetics, zero charge potential (pHpzc) and adsorption isotherms, to analyze the kinetic model that fitted the process, the explanation... [more]
Biological Pretreatment of Oil Palm Empty Fruit Bunch by Schizophyllum commune ENN1 without Washing and Nutrient Addition
Enis Natasha Noor Arbaain, Ezyana Kamal Bahrin, Mohamad Faizal Ibrahim, Yoshito Ando, Suraini Abd-Aziz
September 5, 2019 (v1)
Subject: Biosystems
Keywords: biological pretreatment, fermentable sugar, lignin, OPEFB, Schizophyllum commune
Washing and drying are common steps for oil palm empty fruit bunch (OPEFB) preparation prior to pretreatment. However, the mass balance of OPEFB preparation proved a major loss of OPEFB during the washing and drying steps. An indigenous fungus, Schizophyllum commune ENN1 was used for delignification of unwashed OPEFB in biological pretreatment without nutrient addition. S. commune ENN1 achieved a maximum lignin removal of 53.8% after 14 days of biological pretreatment of unwashed OPEFB. S. commune ENN1 was able to grow on unwashed OPEFB during biological pretreatment at 55% of moisture content and 5% of oil residue. The highest amount of reducing sugars obtained from OPEFB pretreated by S. commune ENN1 was 230.4 ± 0.19 mg/g with 54% of hydrolysis yield at 96 h. In comparison, the sugar yield of OPEFB pretreated by Phanerochaete chrysosporium was 101.2 ± 0.04 mg/g. This study showed that S. commune ENN1 was feasible to remove lignin of OPEFB through biological pretreatment for enzymatic... [more]
Kinetics of Arsenic Removal in Waste Acid by the Combination of CuSO4 and Zero-Valent Iron
Yunhao Xi, Yongguang Luo, Jingtian Zou, Jing Li, Tianqi Liao, Libo Zhang, Chen Wang, Xiteng Li, Guo Lin
September 5, 2019 (v1)
Keywords: arsenic, kinetic, waste acid, zero-valent iron
In this study, we investigated the kinetics of arsenic removal from waste acid by the combination of zero-valent iron (ZVI) and CuSO4. ZVI samples were characterized by X-ray diffraction and scanning electron microscopy before and after arsenic removal; the results showed that after the arsenic removal reaction, As2O3 and magnetite phases were detected on the surface of these samples. Kinetic studies were carried out under different reaction temperatures, with different CuSO4 concentrations, and with different iron to arsenic molar ratios (Fe/As). The kinetic data of the arsenic removal were fitted to different kinetic models. The fitting results showed that the arsenic removal process could be described by the shrinking core model, controlled by residual layer diffusion. The apparent activation energy of the reaction was 9.0628 kJ/mol, the reaction order with the CuSO4 concentrations was −0.12681, and the reaction order with the molar ratio of iron to arsenic (Fe/As) was 3.152.
A Fuzzy Multicriteria Decision-Making (MCDM) Model for Sustainable Supplier Evaluation and Selection Based on Triple Bottom Line Approaches in the Garment Industry
Chia-Nan Wang, Ching-Yu Yang, Hung-Chun Cheng
September 5, 2019 (v1)
Keywords: FAHP, fuzzy logics, garment industry, Optimization, supplier selection, TOPSIS, triple bottom line
Vietnam’s garment industry is facing many challenges, including domestic competition and the global market. The free trade agreement, which Vietnam signed, includes environmental barriers, sustainable development, and green development. The agreement further requires businesses to make efforts to improve not only product quality but also the production process. In cases when enterprises cause environmental pollution in the production process and do not apply solutions to reduce waste, save energy, and natural resources, there is a risk of no longer receiving orders or orders being rejected, especially orders from the world’s major branded garment companies. In this research, the authors propose a multicriteria decision-making model (MCDM) for optimizing the supplier evaluation and selection process for the garment industry using sustainability considerations. In the first stage of this research, all criteria affecting supplier selection are determined by a triple bottom line (TBL) mode... [more]
Wind Energy Generation Assessment at Specific Sites in a Peninsula in Malaysia Based on Reliability Indices
Athraa Ali Kadhem, Noor Izzri Abdul Wahab, Ahmed N. Abdalla
September 5, 2019 (v1)
Keywords: Malaysia, reliability indices, Sequential Monte Carlo Simulation, wind farms
This paper presents a statistical analysis of wind speed data that can be extremely useful for installing a wind generation as a stand-alone system. The main objective is to define the wind power capacity’s contribution to the adequacy of generation systems for the purpose of selecting wind farm locations at specific sites in Malaysia. The combined Sequential Monte Carlo simulation (SMCS) technique and the Weibull distribution models are employed to demonstrate the impact of wind power in power system reliability. To study this, the Roy Billinton Test System (RBTS) is considered and tested using wind data from two sites in Peninsular Malaysia, Mersing and Kuala Terengganu, and one site, Kudat, in Sabah. The results showed that Mersing and Kudat were best suitable for wind sites. In addition, the reliability indices are compared prior to the addition of the two wind farms to the considered RBTS system. The results reveal that the reliability indices are slightly improved for the RBTS sy... [more]
Special Issue “Renewable Polymers: Processing and Chemical Modifications”
Tizazu Mekonnen, Marc A. Dubé
September 5, 2019 (v1)
Subject: Other
The use of renewable resources for polymer production is receiving substantial and ever-growing interest [...]
Analysis of Dynamic Characteristics of a 600 kW Storage Type Wind Turbine with Hybrid Hydraulic Transmission
Zengguang Liu, Yanhua Tao, Liejiang Wei, Peng Zhan, Daling Yue
September 5, 2019 (v1)
Keywords: double closed loop control, energy storage system, hybrid hydraulic transmission, hydraulic wind turbine
In order to improve the efficiency and convenience of wind energy storage and solve the reproducibility of the hydraulic wind turbine, we present a storage type wind turbine with an innovative hybrid hydraulic transmission, which was adopted in the development of a 600 kW storage type wind turbine experimental platform. The whole hydraulic system of the storage type wind turbine is mainly an ingenious combination of a closed loop transmission and an open loop one, which can also be divided into three parts: hydraulic variable speed, hydraulic energy storage, power generation. For the study focusing on the capture and storage of wind energy, the mathematical model of the wind turbine except for the power generation was established under MATLAB/Simulink. A double closed loop control strategy is proposed to achieve the wind wheel speed regulation and wind energy storage. The dynamic simulations of the 600 kW storage type wind turbine experimental prototype were carried out under two diffe... [more]
Theoretical Study of the Adsorption Process of Antimalarial Drugs into Acrylamide-Base Hydrogel Model Using DFT Methods: The First Approach to the Rational Design of a Controlled Drug Delivery System
Eliceo Cortes, Edgar Márquez, José R. Mora, Esneyder Puello, Norma Rangel, Aldemar De Moya, Jorge Trilleras
September 5, 2019 (v1)
Subject: Biosystems
Keywords: binding energy, computational modeling, drug-delivery system, hydrogel, hydrogen bond, Plasmodium falciparum
The interaction between three widely used antimalarial drugs chloroquine, primaquine and amodiaquine with acrylamide dimer and trimer as a hydrogel model, were studied by means of density functional theory calculation in both vacuum and water environments, using the functional wb97xd with 6-31++G(d,p) basis set and polarizable continuum model (C-PCM) of solvent. According to binding energy, around −3.15 to −11.91 kJ/mol, the interaction between antimalarial compounds and hydrogel model are exothermic in nature. The extent of interaction found is primaquine > amodiaquine > chloroquine. The natural bond orbital (NBO) calculation and application of second-order perturbation theory show strong charge transfer between the antimalarial and hydrogel model. In addition, the results suggest these interactions are polar in nature, where hydrogen bonds play a principal role in stabilization of the complex. Comparing with the gas-phase, the complexes in the water environment are also stable, with... [more]
Modeling of the Free Radical Copolymerization Kinetics of n-Butyl Acrylate, Methyl Methacrylate and 2-Ethylhexyl Acrylate Using PREDICI®
Javier A. Gómez-Reguera, Eduardo Vivaldo-Lima, Vida A. Gabriel, Marc A. Dubé
September 5, 2019 (v1)
Keywords: 2-ethylhexyl acrylate, methyl methacrylate, Modelling, n-butyl acrylate, polymerization kinetics
Kinetic modeling of the bulk free radical copolymerizations of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (EHA); methyl methacrylate (MMA) and EHA; as well as BA, MMA and EHA was performed using the software PREDICI®. Predicted results of conversion versus time, composition versus conversion, and molecular weight development are compared against experimental data at different feed compositions. Diffusion-controlled effects and backbiting for BA were incorporated into the model as they proved to be significant in these polymerizations. The set of estimated global parameters allows one to assess the performance of these copolymerization systems over a wide range of monomer compositions.
The Effect of Various Nanofluids on Absorption Intensification of CO2/SO2 in a Single-Bubble Column
Soroush Karamian, Dariush Mowla, Feridun Esmaeilzadeh
September 5, 2019 (v1)
Keywords: absorption intensification, bubble column, mass transfer coefficient, nanofluids
Application of nanoparticles in aqueous base-fluids for intensification of absorption rate is an efficient method for absorption progress within the system incorporating bubble-liquid process. In this research, SO2 and CO2 were separately injected as single raising bubbles containing nanofluids to study the impact of nanoparticle effects on acidic gases absorption. In order to do this, comprehensive experimental studies were done. These works also tried to investigate the effect of different nanofluids such as water/Al2O3 or water/Fe2O3 or water/SiO2 on the absorption rate. The results showed that the absorption of CO2 and SO2 in nanofluids significantly increases up to 77 percent in comparison with base fluid. It was also observed that the type of gas molecules and nanoparticles determine the mechanism of mass transfer enhancement by nanofluids. Additionally, our findings indicated that the values of mass transfer coefficient of SO2 in water/Al2O3, water/Fe2O3 and water/SiO2 nanofluid... [more]
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