Records Added in May 2021
Records added in May 2021
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Showing records 76 to 100 of 160. [First] Page: 1 2 3 4 5 6 7 Last
Phenolics Dynamics and Infrared Fingerprints during the Storage of Pumpkin Seed Oil and Thereof Oleogel
Andreea Pușcaș, Andruța Mureșan, Floricuța Ranga, Florinela Fetea, Sevastița Muste, Carmen Socaciu, Vlad Mureșan
May 25, 2021 (v1)
Keywords: chemometrics, Fourier transform infrared spectroscopy, HPLC-MS, oleogels, polyphenols, pumpkin seed oil, storage follow-up
Cold-pressed pumpkin seed oil is a valuable source of bioactive molecules, including phenolic compounds. Oleogels are designed for trans and saturated fats substitution in foods, but also demonstrate protection and delivery of bioactive compounds. Consequently, the present work aimed to assess individual phenolic compounds dynamics and infrared fingerprints during the ambient storage of pumpkin seed oil and thereof oleogel. For oleogels production, a 5% ternary mixture of waxes, composed by 3% beewax, 1% sunflower wax and 1% rice bran wax, was used. Phenolic compounds were extracted by traditional liquid−liquid extraction, followed by HPLC-MS quantification. FTIR (400−4000 cm−1) was used for characterizing and monitoring the oxidative stability of all samples and for the evaluation of intermolecular forces between oleogelator mixtures and oil. Specific wavenumbers indicated oxidative processes in stored sample sets; storage time and sample clustering patterns were revealed by chemometr... [more]
Polyphenolic Profiling of Forestry Waste by UPLC-HDMSE
Colin M. Potter, David L. Jones
May 25, 2021 (v1)
Keywords: I-Class, Phenol-Explorer, phenolomics, polyphenolic, Synapt G2-Si
Polyphenols constitute a diverse array of naturally occurring secondary metabolites found in plants which, when consumed, have been shown to promote human health. Greater consumption may therefore aid in the fight against diseases such as obesity, diabetes, heart disease, cancer, etc. Tree bark is polyphenol-rich and has potential to be used in food supplements. However, it is important to gain insight into the polyphenol profile of different barks to select the material with greatest concentration and diversity. Ultra-performance liquid chromatography (UPLC) was coupled with an ion mobility time-of-flight high-definition/high-resolution mass spectrometer (UPLC-HDMSE) to profile ethanol extracts of three common tree barks (Pinus contorta, Pinus sylvestris, Quercus robur) alongside a commercial reference (Pycnogenol® extracted from Pinus pinaster). Through the use of Progenesis QI informatics software, 35 high scoring components with reported significance to health were tentatively iden... [more]
Oxidative Potential Induced by Ambient Particulate Matters with Acellular Assays: A Review
Lanfang Rao, Luying Zhang, Xingzi Wang, Tingting Xie, Shumin Zhou, Senlin Lu, Xinchun Liu, Hui Lu, Kai Xiao, Weiqian Wang, Qingyue Wang
May 25, 2021 (v1)
Subject: Biosystems
Keywords: acellular assay, ambient particles, oxidative potential, quinones, transition metals
Acellular assays of oxidative potential (OP) induced by ambient particulate matters (PMs) are of great significance in screening for toxicity in PMs. In this review, several typical OP measurement techniques, including the respiratory tract lining fluid assay (RTLF), ascorbate depletion assay (AA), dithiothreitol assay (DTT), chemiluminescent reductive acridinium triggering (CRAT), dichlorofluorescin assay (DCFH) and electron paramagnetic/spin resonance assay (EPR/ESR) are discussed and their sensitivity to different PMs species composition, PMs size distribution and seasonality is compared. By comparison, the DTT assay tends to be the preferred method providing a more comprehensive measurement with transition metals and quinones accumulated in the fine PMs fraction. Specific transition metals (i.e., Mn, Cu, Fe) and quinones are found to contribute OPDTT directly whereas the redox properties of PMs species may be changed by the interactions between themselves. The selection of the appr... [more]
The Influence of Starch Modification with Amylosucrase Treatment on Morphological Features
Hyeyoung Lee, Inmyoung Park
May 25, 2021 (v1)
Keywords: amylosucrase-modified starch, cross-sectioned particle, low glycemic starch, morphology, particle size distribution
Amylosucrase (AS) is a starch-modifying enzyme from Neisseria polysaccharea used to produce low-glycemic starches such as slowly digestible starch (SDS) and resistant starch (RS). The morphology of native, control, and AS-modified waxy corn starches (230 and 460 U) was examined using a particle size analyzer and field-emission scanning electron microscopy (FE-SEM). AS modification of the starch elongated the glucose and resulted in higher SDS and RS contents. The mean particle sizes of the control, 230 U-AS-, and 460 U-AS-treated starches were 56.6 µm, 128.0 µm, and 176.5 μm, respectively. The surface of the 460 U-AS-treated starch was entirely porous and coral-like, while the 230 U-AS-treated starch had a partial dense and flat surface which did not react with AS. FE-SEM of the granule cross section confirmed that the center contained a dense and flat region without any evidence of AS reaction to either of the AS-treated starches. It was assumed that the particle size and porous and s... [more]
Stem Cell Therapy for Thromboangiitis Obliterans (Buerger’s Disease)
Biraja C. Dash, Hassan Peyvandi, Kaiti Duan, Edward Richardson, Sifon U. Ndon, Kyle S. Gabrick, Athena A. Faz, John A. Persing, Alan Dardik, Henry C. Hsia
May 25, 2021 (v1)
Subject: Biosystems
Keywords: angiogenesis, immunomodulation, inflammation, mesenchymal stem cell, pluripotent stem cell, thromboangiitis obliterans
Buerger’s disease or Thromboangiitis Obliterans (TAO) is a nonatherosclerotic segmental vascular disease which affects small and medium arteries and veins in the upper and lower extremities. Based on pathological findings, TAO can be considered as a distinct form of vasculitis that is most prevalent in young male smokers. There is no definitive cure for this disease as therapeutic modalities are limited in number and efficacy. Surgical bypass has limited utility and 24% of patients will ultimately require amputation. Recently, studies have shown that therapeutic angiogenesis and immunomodulatory approaches through the delivery of stem cells to target tissues are potential options for ischemic lesion treatment. In this review, we summarize the current knowledge of TAO treatment and provide an overview of stem cell-based treatment modalities.
Study of a Method to Effectively Remove Char Byproduct Generated from Fast Pyrolysis of Lignocellulosic Biomass in a Bubbling Fluidized Bed Reactor
Jong Hyeon Ha, In-Gu Lee
May 25, 2021 (v1)
Keywords: BFB reactor, bio-oil, biochar, fast pyrolysis, inner and outer tubes, wood sawdust
A critical issue in the design of bubbling fluidized bed reactors for biomass fast pyrolysis is to maintain the bed at a constant level to ensure stable operation. In this work, a bubbling fluidized bed reactor was investigated to deal with this issue. The reactor consists of inner and outer tubes and enables in situ control of the fluidized-bed level in the inner-tube reactor with a mechanical method during biomass fast pyrolysis. The significant fraction of biochar produced from the fast pyrolysis in the inner-tube reactor was automatically removed through the annulus between the inner and outer tubes. The effect of pyrolysis temperature (426−528 °C) and feeding rate (0.8−1.8 kg/h) on the yield and characteristics of bio-oil, biochar, and gaseous products were examined at a 15 L/min nitrogen carrier gas flow rate for wood sawdust with a 0.5−1.0 mm particle size range as a feed. The bio-oil reached a maximum yield of 62.4 wt% on a dry basis at 440 °C, and then slowly decreased with in... [more]
Effect of Thermally-Treated Chips on Density of AlMgSi Alloys Recycled Using Solid-State Technique
Abdullah Wagiman, Mohammad Sukri Mustapa, Shazarel Shamsudin, Mohd Amri Lajis, Rosli Asmawi, Mohammed H Rady, Mohd Shahir Yahya
May 25, 2021 (v1)
Subject: Materials
Keywords: density, direct hot extrusion, thermally formed alumina, thermally-treated chip
Solid-state recycling is a sustainable technique for recycling aluminium scrap, and the process before recycling is essential to control the physical properties of the product. In this work, the effect of the thermally-treated chips on the extrudate density was investigated. The aluminium chips were thermally-treated to enrich the alumina layer and reduce compaction pressure during chips compaction before recycled using direct hot extrusion. The chips that were transformed into compacted billets were extruded directly without melting and conducted according to 24 full factorial experimental design. The density test on the recycle extrudate found that the density variation ranged from 2724 to 2983 kg/m3. The ANOVA result showed that all factors investigated were statistically significant. The most significant factor was the preheating temperature, followed by extrusion ratio, chip treatment temperature, chip treatment time, and the interaction of chip treatment-time−extrusion ratio. The... [more]
Impact of Gas Control Policy on the Gas Accidents in Coal Mine
Wei Ke, Kai Wang
May 25, 2021 (v1)
Subject: Energy Policy
Keywords: coal mine, control policy, delphi method, gas accident, intervention degree
Coal mine gas accidents pose a serious threat to the safety of coal mines in China. To prevent such accidents, the Chinese government and relevant agencies have issued a number of related control policies, though the effect of these policies on gas accidents is still lacking. In this study, the relevant data of coal mine gas accidents in China from 2003 to 2018 are sorted and analyzed. The analysis results show that the number of coal mine accidents and deaths has decreased significantly. However, gas accidents account for the highest proportion of deaths and pose the largest threat, compared with other types of accidents. Subsequently, the developmental stages of China’s gas control policies are summarized; they are the independent development stage, the promotion stage and the consolidation stage. A method of calculating the intervention degree of the gas control policies is proposed. The results show that the policy intervention degree is the highest, and the number of accidents is... [more]
Study on Turbulence Intensity Behavior under a Large Range of Temperature Variation
Junsik Lee, Jae-Hak Lee
May 25, 2021 (v1)
Keywords: high-temperature, turbulence intensity, velocity fluctuation, wind tunnel
The turbulence intensity (TI) is defined as the ratio of fluctuation from the standard deviation of wind velocity to the mean value. Many studies have been performedon TI for flow dynamics and adapted various field such as aerodynamics, jets, wind turbines, wind tunnel apparatuses, heat transfer, safety estimation of construction, etc.The TI represents an important parameter for determining the intensity of velocity variation and flow quality in industrial fluid mechanics. In this paper, computational fluid dynamic (CFD) simulation of TI alteration with increasing temperature has been performed using the finite volume method. A high-temperature—maximum 300 degrees Celsius (°C)—wind tunnel test rig has been used as theapparatus, and velocity was measured by an I-type hot-wire anemometer. The velocity and TI of the core test section were operated at several degrees of inlet temperatures at anair velocity of 20 m/s. The magnitude of TI has a relationship with boundary layer development. T... [more]
Numerical Simulation and Experimental Research on Flow Force and Pressure Stability in a Nozzle-Flapper Servo Valve
Jian Kang, Zhaohui Yuan, Muhammad Tariq Sadiq
May 25, 2021 (v1)
Keywords: mathematical model, numerical simulation, pressure stability, servo valve, transient flow force
In the nozzle flapper servo valve, the transient flow force on the flapper is the fundamental reason that affects the pressure stability. The pressure pulsation in the pilot stage causes forced vibration of the flapper, and its deviation will directly influence the control pressure difference, which will make the pressure appear unstable. In order to grasp the principle and characteristics of transient flow force and its influence on pressure stability, a mathematical model of flapper displacement and control pressure is derived. For collecting the dynamic changes of the transient flow force and recording the motion behavior of the flapper, a three-dimensional model of the pilot-stage is established. Numerical simulations of turbulence phenomenon analysis are conducted with a variation of flapper displacement ranging from 5 μm to 20 μm. It can be concluded that the change trend of the flapper displacement is similar to the steady-state flow force and the transient flow force pulsation... [more]
Quality of Sugar Beets under the Effects of Digestate Application to the Soil
Andrzej Baryga, Bożenna Połeć, Andrzej Klasa
May 25, 2021 (v1)
Keywords: beet pulp, beet quality parameters, digestate, gasifier, sugar beet
Management of digestate from production of biogas has a great environmental importance. One of feedstock for biogas generation is beet pulp, a side product of sugar beet processing plant. In the paper a closed loop of beet pulp utilization at sugar beet plantation is presented. Effects of soil application of digestate obtained from digestion of sugar beet pulp were compared with standard mineral fertilizers. The field experiment was performed in three successive growing seasons. The studies were concentrated on quality of sugar beets grown under effects of two fertilization treatments—soil application of digestate cv. standard mineral fertilizers. It was found that some important quality indices (weight of single sugar beet root, content of sucrose in root tissues) were higher for beet harvested from digestate treatment compared to standard mineral fertilization (control). The concentration of harmful component (amide nitrogen) in sugar beets grown under conditions of digestate soil ap... [more]
Biological Evaluation of Azetidine-2-One Derivatives of Ferulic Acid as Promising Anti-Inflammatory Agents
Maria Drăgan, Cătălina Daniela Stan, Andreea Teodora Iacob, Oana Maria Dragostin, Mihaela Boancă, Cătălina Elena Lupuşoru, Carmen Lăcrămioara Zamfir, Lenuţa Profire
May 25, 2021 (v1)
Subject: Biosystems
Keywords: acute inflammation, azetidine-2-one derivatives, biochemical parameters, chronic inflammation, ferulic acid, histopathological study
The purpose of this study was to evaluate the in vivo biological potential of new azetidine-2-one derivatives of ferulic acid (6a−f). First, the in vivo acute toxicity of azetidine-2-one derivatives of ferulic acid on Swiss white mice was investigated and, based on the obtained results, it can be stated that the studied derivatives belong to compounds with moderate toxicity. The in vivo anti-inflammatory potential of these derivatives was determined in a model of acute inflammation induced by carrageenan in rats and in a chronic inflammation model induced in rats using the granuloma test. In the acute inflammation model, all the studied compounds had a maximum anti-inflammatory effect 24 h after administration, which suggests that these compounds may be classified, from a pharmacokinetic point of view, in the category of long-acting compounds. The most active compound in the series was found to be compound 6b. In the case of the chronic inflammation model, it was observed that the stud... [more]
Modeling, Control, and Prediction of the Spread of COVID-19 Using Compartmental, Logistic, and Gauss Models: A Case Study in Iraq and Egypt
Mahmoud A. Ibrahim, Amenah Al-Najafi
May 25, 2021 (v1)
Keywords: compartmental model, control measures, COVID-19, Gaussian model, logistic growth model, parameter estimation, second wave, sensitivity analysis
In this paper, we study and investigate the spread of the coronavirus disease 2019 (COVID-19) in Iraq and Egypt by using compartmental, logistic regression, and Gaussian models. We developed a generalized SEIR model for the spread of COVID-19, taking into account mildly and symptomatically infected individuals. The logistic and Gaussian models were utilized to forecast and predict the numbers of confirmed cases in both countries. We estimated the parameters that best fit the incidence data. The results provide discouraging forecasts for Iraq from 22 February to 8 October 2020 and for Egypt from 15 February to 8 October 2020. To provide a forecast of the spread of COVID-19 in Iraq, we present various simulation scenarios for the expected peak and its timing using Gaussian and logistic regression models, where the predicted cases showed a reasonable agreement with the officially reported cases. We apply our compartmental model with a time-periodic transmission rate to predict the possibl... [more]
Economic Analysis of a Freeze-Drying Cycle
Lorenzo Stratta, Luigi C. Capozzi, Simone Franzino, Roberto Pisano
May 25, 2021 (v1)
Keywords: costs analysis, freeze-drying, lyophilization, Optimization
Freeze-drying has always been considered an extremely expensive procedure to dehydrate food or pharmaceutical products, and for this reason, it has been employed only if strictly necessary or when the high added value of the final product could justify the costs. However, little effort has been made to analyze the factors that make this technology so unaffordable. In this work, a model was proposed to calculate in detail the operational (OC) and capital costs (CC) of a freeze-drying cycle and an evaluation of the process bottlenecks was made. The main result is that the process itself, contrary to the classic belief, is not the most expensive part of freeze-drying, while the initial investment is the real limiting factor. Under this consideration, the optimization of a freeze-drying cycle should be formulated in order to fit more cycles in the lifespan of the apparatus, instead of merely reducing the power consumption of the machine.
Minimizing Tardiness Penalty Costs in Job Shop Scheduling under Maximum Allowable Tardiness
Jae-Gon Kim, Hong-Bae Jun, June-Young Bang, Jong-Ho Shin, Seong-Hoon Choi
May 25, 2021 (v1)
Keywords: job shop scheduling, maximum allowable tardiness, probabilistic dispatching rules, semiconductor, tardiness penalty
In many manufacturing or service industries, there exists maximum allowable tardiness for orders, according to purchase contracts between the customers and suppliers. Customers may cancel their orders and request compensation for damages, for breach of contract, when the delivery time is expected to exceed maximum allowable tardiness, whereas they may accept the delayed delivery of orders with a reasonable discount of price within maximum allowable tardiness. Although many research works have been produced on the job shop scheduling problem relating to minimizing total tardiness, none of them have yet considered problems with maximum allowable tardiness. In this study, we solve a job shop scheduling problem under maximum allowable tardiness, with the objective of minimizing tardiness penalty costs. Two kinds of penalty costs are considered, i.e., one for tardy jobs, and the other for canceled jobs. To deal with this problem within a reasonable time at actual production facilities, we p... [more]
Equilibrium, Kinetic and Thermodynamic Studies for Sorption of Phosphate from Aqueous Solutions Using ZnO Nanoparticles
Tra Huong Do, Van Tu Nguyen, Quoc Dung Nguyen, Manh Nhuong Chu, Thi Cam Quyen Ngo, Lam Van Tan
May 25, 2021 (v1)
Keywords: aqueous solution, equilibrium, kinetic, nanoparticles, phosphate, thermodynamic, ZnO
In this study, ZnO nanoparticles were fabricated by using the hydrothermal method for adsorption of phosphate from wastewater. The obtained ZnO nanorods were characterized by powder X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), specific surface area (BET) and energy dispersive X-ray spectroscopy (EDS). The ZnO materials were applied for adsorption of phosphate from water using batch experiments. The effects of pH (4−10), adsorption time (30−240 min), the amount of adsorbent (0.1−0.7 g/L) and initial concentration of phosphate (147.637−466.209 mg/L) on the adsorption efficiency were investigated. The optimum condition was found at pH = 5 and at an adsorption time of 150 min. The adsorption was fitted well with the Langmuir isotherm and the maximum adsorption capacity was calculated to be 769.23 mg/g. These results show that ZnO nanomaterial would highly promising for adsorbing phosphate from water. The adsorption of phosphate on ZnO nanomaterials follows the... [more]
A Numerical Study on the Pilot Injection Conditions of a Marine 2-Stroke Lean-Burn Dual Fuel Engine
Hao Guo, Song Zhou, Jiaxuan Zou, Majed Shreka
May 25, 2021 (v1)
Keywords: Computational Fluid Dynamics, dual-fuel engine, pre-combustion chamber, Simulation, two-stroke
The global demand for clean fuels is increasing in order to meet the requirements of the International Maritime Organization (IMO) of 0.5% global Sulphur cap and Tier III emission limits. Natural gas has begun to be popularized on liquefied natural gas (LNG) ships because of its low cost and environment friendly. In large-bore marine engines, ignition with pilot fuel in the prechamber is a good way to reduce combustion variability and extend the lean-burn limit. However, the occurrence of knock limits the increase in power. Therefore, this paper investigates the effect of pilot fuel injection conditions on performance and knocking of a marine 2-stroke low-pressure dual-fuel (LP-DF) engine. The engine simulations were performed under different pilot fuel parameters. The results showed that the average in-cylinder temperature, the average in-cylinder pressure, and the NOx emissions gradually decreased with the delay of the pilot injection timing. Furthermore, the combustion situation gra... [more]
Use of Titanium Dioxide (TiO2) Nanoparticles as Reinforcement Agent of Polysaccharide-Based Materials
Luis Miguel Anaya-Esparza, Zuamí Villagrán-de la Mora, José Martín Ruvalcaba-Gómez, Rafael Romero-Toledo, Teresa Sandoval-Contreras, Selene Aguilera-Aguirre, Efigenia Montalvo-González, Alejandro Pérez-Larios
May 25, 2021 (v1)
Subject: Materials
Keywords: cross-linking agent, functionalization, hybrid material, polysaccharides, titanium dioxide
In recent years, a strong interest has emerged in polysaccharide-hybrid composites and their potential applications, which have interesting functional and technological properties. This review summarizes and discusses the reported advantages and limitations of the functionalization of conventional and nonconventional polysaccharides by adding TiO2 nanoparticles as a reinforcement agent. Their effects on the mechanical, thermal, and UV-barrier properties as well as their water-resistance are discussed. In general, the polysaccharide−TiO2 hybrid materials showed improved physicochemical properties in a TiO2 content-dependent response. It showed antimicrobial activity against bacteria (gram-negative and gram-positive), yeasts, and molds with enhanced UV-protective effects for food and non-food packaging purposes. The reported applications of functionalized polysaccharide−TiO2 composites include photocatalysts (dye removal from aqueous media and water purification), biomedical (wound-heali... [more]
A Potential Inhibition Process of Ricin Protein with the flavonoids Quercetin and Epigallocatechin Gallate. A Quantum-Chemical and Molecular Docking Study
Mayra Cristina Martínez-Ceniceros, Linda-Lucila Landeros-Martínez, Nora-Aydeé Sánchez-Bojorge, Fabiola Sandoval-Salas, Hilda Amelia Piñón-Castillo, León Raúl Hernández-Ochoa, Luz María Rodríguez-Valdez
May 25, 2021 (v1)
Keywords: charge transfer, DFT, epigallocatechin gallate, MEP, molecular docking, molecular interactions, quercetin, ricin
Castor bean (Ricinus Communis) oil has been reported as one of the most important bio-based fuels; however, high amounts of toxic solid residue are generated in the production. This toxicity is due to several molecules, ricin protein being the most studied compound. The inhibition of the ricin protein is essential for eliminating its toxicity. The objective of this study is to predict the possible inhibition process via the interactions between the ricin protein and the flavonoids quercetin (Q) and epigallocatechin gallate (EGCG). The molecular structures of the complexes formed between the ricin protein and flavonoids were studied using quantum-chemical and molecular docking calculations to analyze the type of interaction, active site of the protein, binding energies, and different conformations in the inhibition process. Different methodologies were applied for the molecular structure determination; the best approximation was obtained with B3LYP/6-31G (d,p) theoretical methodology. M... [more]
Unsteady-State Mathematical Modeling of Hydrocarbon Feedstock Pyrolysis
Igor Dolganov, Ajur Bunaev, Irena Dolganova
May 25, 2021 (v1)
Keywords: hydrocarbon feedstock, mathematical model, pyrolysis, unsteady-state
Hydrocarbon feedstock pyrolysis is an important method for obtaining monomers that are then used to produce various polymer materials. During this process, a mixture of hydrocarbons is heated at a high temperature and in the absence of oxygen. Because of the side reactions of polymerization and polycondensation, coke products are formed and settle on the inner walls of the coil. This decreases the technical efficiency of the hydrocarbon pyrolysis furnace during its operation, making the process unsteady. In the present research, we developed an unsteady-state mathematical model of hydrocarbon feedstock pyrolysis in order to improve the monitoring, forecasting, and optimization of this technological process. This model can calculate the rate of coke deposition along the length of the coil, considering the technological parameters and the composition of the supplied raw materials (the calculated value of coke deposition rate equals 0.01 mm/day). It was shown that with an increase in the... [more]
A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine
Ujjwal Shrestha, Young-Do Choi
May 24, 2021 (v1)
Keywords: Computational Fluid Dynamics, fixed flow passage, flow uniformity, Francis turbine, shape optimization
In recent times, optimization began to be popular in the turbomachinery field. The development of computational fluid dynamics (CFD) analysis and optimization technology provides the opportunity to maximize the performance of hydro turbines. The optimization techniques are focused mainly on the rotating components (runner and guide vane) of the hydro turbines. Meanwhile, fixed flow passages (stay vane, casing, and draft tube) are essential parts for the proper flow uniformity in the hydro turbines. The suppression of flow instabilities in the fixed flow passages is an inevitable process to ensure the power plant safety by the reduction of vortex-induced vibration and pressure pulsation in the hydro turbines. In this study, a CFD-based shape design optimization process is proposed with response surface methodology (RSM) to improve the flow uniformity in the fixed flow passages of a Francis hydro turbine model. The internal flow behaviors were compared between the initial and optimal sha... [more]
Direct Solid Oxide Electrolysis of Carbon Dioxide: Analysis of Performance and Processes
Severin Foit, Lucy Dittrich, Tobias Duyster, Izaak Vinke, Rüdiger-A. Eichel, L. G. J. (Bert) de Haart
May 24, 2021 (v1)
Keywords: Carbon Dioxide, carbon dioxide reduction, carbon dioxide utilization, CO2-electrolysis, high-temperature electrolysis, solid oxide electrolysis
Chemical industries rely heavily on fossil resources for the production of carbon-based chemicals. A possible transformation towards sustainability is the usage of carbon dioxide as a source of carbon. Carbon dioxide is activated for follow-up reactions by its conversion to carbon monoxide. This can be accomplished by electrochemical reduction in solid oxide cells. In this work, we investigate the process performance of the direct high-temperature CO2 electrolysis by current-voltage characteristics (iV) and Electrochemical Impedance Spectroscopy (EIS) experiments. Variations of the operation parameters temperature, load, fuel utilization, feed gas ratio and flow rate show the versatility of the procedure with maintaining high current densities of 0.75 up to 1.5 A·cm−2, therefore resulting in high conversion rates. The potential of the high-temperature carbon dioxide electrolysis as a suitable enabler for the activation of CO2 as a chemical feedstock is therefore appointed and shown.
Experimental Determination of the Energetic Performance of a Racing Motorcycle Battery-Pack
Pablo Esparza, Sandra Castano-Solis, David Jiménez-Bermejo, Jesús Fraile Ardanuy, Manuel Merino
May 24, 2021 (v1)
Keywords: battery-pack sizing, electric motorcycle prototype, energetic performance, experimental results, performance tests
This paper presents the evaluation of the energetic performance of the battery-pack from the motorcycle prototype EME 16E. This racing prototype was developed by a student team from the Universidad Politécnica de Madrid (UPM) to participate in the MotoStudent competition during 2015−2016. This study includes the sizing and assembly of the motorcycle’s battery-pack under strict regulations and a limited budget. The prototype was also tested under different performance conditions, such as laboratory tests and racing circuits. Experimental results show that the proposed battery-pack is capable of supplying the energy and power necessary to drive the motorcycle in all cases analyzed.
Fabrication of Macroporous Nafion Membrane from Silica Crystal for Ionic Polymer-Metal Composite Actuator
Xiaojun Zhang, Man Wang, Manhong Li, Minglu Zhang, Chengwei Zhang
May 24, 2021 (v1)
Subject: Materials
Keywords: ionic polymer-metal composite actuator, macroporous structure, nafion membrane, nanocomposites, nanoparticles, silica crystal
Nafion membrane with macropores is synthesized from silica crystal and composited with Pt nanoparticles to fabricate macroporous ionic polymer-metal composite (M-IPMC) actuator. M-IPMC shows highly dispersed small Pt nanoparticles on the porous walls of Nafion membrane. After the electromechanical performance test, M-IPMC actuator demonstrates a maximum displacement output of 19.8 mm and a maximum blocking force of 8.1 mN, far better than that of IPMC actuator without macroporous structure (9.6 mm and 2.8 mN) at low voltages (5.8−7.0 V). The good electromechanical performance can be attributed to interconnected macropores that can improve the charge transport during the actuation process and can allow the Pt nanoparticles to firmly adsorb, leading to a good electromechanical property.
Phenolic Acids from Lycium barbarum Leaves: In Vitro and In Silico Studies of the Inhibitory Activity against Porcine Pancreatic α-Amylase
Luna Pollini, Alessandra Riccio, Cristina Juan, Carmela Tringaniello, Federica Ianni, Francesca Blasi, Jordi Mañes, Antonio Macchiarulo, Lina Cossignani
May 24, 2021 (v1)
Keywords: antioxidant activity, bioactives, food waste, goji leaves, hypoglycaemic activity, molecular docking, UAE
Nowadays, bioactive compounds from vegetable food and waste are of great interest for their inhibitory potential against digestive enzymes. In the present study, the inhibitory activity of methanolic extract from Lycium barbarum leaves on porcine pancreas α-amylase has been studied. The α-amylase inhibitory activity of the constituent phenolic acids was also investigated. The leaves were extracted by ultrasound-assisted method, one of the most efficient techniques for bioactive extraction from plant materials, and then the phenolic acids were identified by Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) Liquid Chromatography/Mass Spectrometry (LC/MS). Chlorogenic and salicylic acids were the most abundant phenolic acids in L. barbarum leaf extract. The inhibitory effect against α-amylase, determined for individual compounds by in vitro assay, was higher for chlorogenic, salicylic, and caffeic acids. L. barbarum leaf extract showed an appreciable α-amylase inhibitory effect in a concent... [more]
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