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Showing records 35991 to 36015 of 43292. [First] Page: 1 1437 1438 1439 1440 1441 1442 1443 1444 1445 Last
A Spinel (FeNiCrMnMgAl)3O4 High Entropy Oxide as a Cycling Stable Anode Material for Li-Ion Batteries
Yu Zheng, Xin Wu, Xuexia Lan, Renzong Hu.
February 22, 2023 (v1)
Subject: Materials
Keywords: in-situ X-ray diffraction, lithium-ion battery, phase transformation, spinel-type high entropy oxide
Recently, high entropy oxides (HEO) with special stabilization effects have been widely investigated as new anode materials for lithium-ion batteries. However, the lithium storage mechanism of HEO is still under debate. In this work, we applied a modified solution combustion synthesis method with a subsequent ball milling refinement process to prepare a six-component (FeNiCrMnMgAl)3O4 spinel high entropy oxide (6-SHEO). The novel 6-SHEO anode features outstanding electrochemical performance, enabling a stable capacity of 657 mAh g−1 at a current rate of 0.2 A g−1 after 200 cycles, and good high-rate capability with 350 mAh g−1 even at 4 A g−1. In addition, the lithium storage behavior of this 6-SHEO anode was explored in detail through in-situ XRD and ex-situ TEM approaches. Surprisingly, a reversible spinel to rock salt phase transition behavior and spinel phase residue phenomenon was firstly observed by this route. Furthermore, for better understanding of the phase change behavior in... [more]
Approximate Models of Microbiological Processes in a Biofilm Formed on Fine Spherical Particles
Szymon Skoneczny, Monika Cioch-Skoneczny.
February 22, 2023 (v1)
Keywords: biodegradation, biofilm dynamics, mathematical modeling
This paper concerns the dynamical modeling of the microbiological processes that occur in the biofilms that are formed on fine inert particles. Such biofilm forms e.g. in fluidized-bed bio-reactors, expanded bed biofilm reactors and biofilm air-lift suspension reactors. An approximate model that is based on the Laplace−Carson transform and a family of approximate models that are based on the concept of the pseudo-stationary substrate concentration profile in the biofilm were proposed. The applicability of the models to the microbiological processes was evaluated following Monod or Haldane kinetics in the conditions of dynamical biofilm growth. The use of approximate models significantly simplifies the computations compared to the exact one. Moreover, the stiffness that was present in the exact model, which was solved numerically by the method of lines, was eliminated. Good accuracy was obtained even for large internal mass transfer resistances in the biofilm. It was shown that signific... [more]
Experimental and Numerical Analysis on Mesoscale Mechanical Behavior of Coarse Aggregates in the Asphalt Mixture during Gyratory Compaction
De Zhang, Zhiqiang Cheng, Dajiang Geng, Shengjia Xie, Tao Wang.
February 22, 2023 (v1)
Keywords: contact stress, Discrete Element Method, granular sensor, gyratory compaction, homogenization, isotropy
Compaction is a critical step in asphalt pavement construction. The objective of this study is to analyze the mesoscale mechanical behaviors of coarse aggregates in asphalt mixtures during gyratory compaction through experiments and numerical simulation using the Discrete Element Method (DEM). A novel granular sensor (SmartRock) was embedded in an asphalt mixture specimen to collect compaction response data, including acceleration, stress, rotation angle and temperature. Moreover, the irregularly shaped coarse aggregates were regenerated in the DEM model, and numerical simulations were conducted to analyze the evolution of aggregate interaction characteristics. The findings are as follows: (1) the measured contact stress between particles changes periodically during gyratory compaction, and the amplitude of stress tends to be stable with the increase of compaction cycles; (2) the contact stress of particles is influenced by the shape of aggregates: flat-shaped particles are subjected t... [more]
Thermal Behavior of Ceramic Bodies Based on Estonian Clay from the Arumetsa Deposit with Oil Shale Ash and Clinker Dust Additives
Tiit Kaljuvee, Igor Štubňa, Tomáš Húlan, Mai Uibu, Marve Einard, Rainer Traksmaa, Mart Viljus, Jekaterina Jefimova, Andres Trikkel.
February 22, 2023 (v1)
Keywords: ceramics, clay, clinker dust, FTIR, kinetics, oil shale ash, TG-DTA-MS, TMA
The thermal behavior of green clay samples from the Arumetsa and Füzérradvány deposits (Hungary) and the influence of two new types of Estonian oil shale (OS) ashes and cement bypass dust (clinker dust) additives on it were the objectives of this study. Thermal and thermo-dilatometric analysis methods were applied using a Setaram Setsys 1750 thermoanalyzer coupled with a Pfeiffer Omnistar spectrometer and a Setaram Setsys 1750 CS Evolution dilatometer. The kinetic parameters were calculated based on the differential isoconversional method of Friedman. The results of the thermal analysis of clays and blends indicated the emission of physically bound water at 200−250 °C. At temperatures from 200−250 °C to 550−600 °C the release of water is caused by oxidation of organic matter and dehydroxylation of different clay minerals like illite, illite-smectite, mica and kaolin. From blends, in addition, also from the decomposition of portlandite. The emission of CO2 at these temperatures was a re... [more]
The Effect of Electromagnetic Microwave Radiation on Methane Fermentation of Selected Energy Crop Species
Marcin Zieliński, Marcin Dębowski, Joanna Kazimierowicz.
February 22, 2023 (v1)
Keywords: biogas, electromagnetic microwave radiation, energy crops, methane, methane fermentation
The aim of the present study was to determine how thermal stimulation via electromagnetic microwave radiation impacts the yields of biogas and methane produced by methane fermentation of five selected energy crop species in anaerobic reactors. The resultant performance was compared with that of reactors with conventional temperature control. The highest biogas production capacity was achieved for maize silage and Virginia mallow silage (i.e., 680 ± 28 dm3N/kgVS and 506 ± 16 dm3N/kgVS, respectively). Microwave radiation as a method of heating anaerobic reactors provided a statistically-significantly boost in methane production from maize silage (18% increase). Biomethane production from maize silage rose from 361 ± 12 dm3N/kgVS to 426 ± 14 dm3N/kgVS. In the other experimental variants, the differences between methane concentrations in the biogas were non-significant.
Recurrent Neural Network-Based Temperature Control System Weight Pruning Based on Nonlinear Reconstruction Error
Yuan Liu, Takahiro Kawaguchi, Song Xu, Seiji Hashimoto.
February 22, 2023 (v1)
Keywords: layer-wise weight pruning, nonlinear reconstruction error, recurrent neural networks, temperature control system
Recurrent Neural Networks (RNNs) have been widely applied in various fields. However, in real-world application, because most devices like mobile phones are limited to the storage capacity when processing real-time information, an over-parameterized model always slows down the system speed and is not suitable to be employed. In our proposed temperature control system, the RNN-based control model processes the real-time temperature signals. It is necessary to compress the trained model with acceptable loss of control performance for further implementation in the actual controller when the system resource is limited. Inspired by the layer-wise neuron pruning method, in this paper, we apply the nonlinear reconstruction error (NRE) guided layer-wise weight pruning method on the RNN-based temperature control system. The control system is established based on MATLAB/Simulink. In order to compress the model size to save the memory capacity of temperature controller devices, we first prove the... [more]
A Short-Cut Data Mining Method for the Mass Spectrometric Characterization of Block Copolymers
Ákos Kuki, Gergő Róth, Anna Nagy, Miklós Zsuga, Sándor Kéki, Tibor Nagy.
February 22, 2023 (v1)
Subject: Materials
Keywords: copolymers, data mining, mass spectrometry, Mass-remainder analysis
A new data mining approach as a short cut method is given for the determination of the copolymer composition from mass spectra. Our method simplifies the copolymer mass spectra by reduction of the number of mass peaks. The proposed procedure, namely the selection of the mass peaks, which is based on the most abundant peak of the mass spectrum, can be performed manually or more efficiently using our recently invented Mass-remainder analysis (MARA). The considerable reduction of the MS spectra also simplifies the calculation of the copolymer quantities for instance the number- and weight-average molecular weights (Mn and Mw, respectively), polydispersity index (Đ = Mw/Mn), average molar fraction (cA) and weight fraction (wA) of the comonomer A and so on. These copolymer properties are in line with those calculated by a reference method taking into account all the mass peaks of the copolymer distribution. We also suggest a highly efficient method and template for the determination of the... [more]
Influence of Graphene Nano Fillers and Carbon Nano Tubes on the Mechanical and Thermal Properties of Hollow Glass Microsphere Epoxy Composites
Kumar D, Kiran Shahapurkar, C. Venkatesh, Muruganandhan R, Vineet Tirth, Chandru Manivannan, Ibrahim M. Alarifi, Manzoore Elahi M. Soudagar, Ahmed S. El-Shafay.
February 22, 2023 (v1)
Subject: Materials
Keywords: carbon nano tube, epoxy, graphene, hollow glass microsphere, mechanical and thermal properties, nano fillers
The present work aimed to analyze the roll of carbon nano tubes and graphene nano fillers on the mechanical and thermal characteristics of hollow glass microsphere reinforced epoxy composites. Composites with varying content of hollow glass microballoons (2, 4, 6, 8, and 10 wt %) reinforced in epoxy matrix were fabricated. Additionally, two more types of composites, one with graphene nano fillers and the other with carbon nano tube at a constant 0.5 wt %, were fabricated with varying weight percentages of hollow glass microballoons (2, 4, 6, 8, and 10%). The composites were fabricated using an open mold casting process. Composites were tested for thermal and mechanical properties. The tensile and flexural moduli were found to rise as the HGM concentration increased. Graphene-filled HGM/epoxy composites revealed the highest modulus compared with HGM/epoxy and HGM/CNT/epoxy composites. The impact strength of all composite types decreased as the HGM content increased. Neat epoxy specimens... [more]
How Environmental Knowledge and Green Values Affect the Relationship between Green Human Resource Management and Employees’ Green Behavior: From the Perspective of Emission Reduction
Shaoying Zhu, Yuxin Wu, Qian Shen.
February 22, 2023 (v1)
Subject: Environment
Keywords: employee green behavior, environmental knowledge, green human resource management, green values, relational psychological contract
Green human resource management (GHRM) determines the green behavior practice of employees and affects the social environment and the realization of “Beautiful China” and “Green Development”. In this study, to explore the impact mechanism of GHRM on employees’ green behavior, employees at all levels in an enterprise were selected to be research subjects and a regulated intermediary model was established, based on social exchange theory and the individual-environment matching theory. This paper investigated the enterprise’s GHRM, personal green behavior, relational psychological contract, environmental knowledge and green values. The results show that GHRM has a significant positive predictive effect on employees’ green behavior, the relational psychological contract plays an intermediary role between GHRM and employees’ green behavior and the intermediary role of the relational psychological contract is regulated by environmental knowledge and green values. These research results expla... [more]
Valorization of Vine Prunings by Slow Pyrolysis in a Fixed-Bed Reactor
Suzana Ioana Calcan, Oana Cristina Pârvulescu, Violeta Alexandra Ion, Cristian Eugen Răducanu, Liliana Bădulescu, Tănase Dobre, Diana Egri, Andrei Moț, Vlad Popa, Mihaela Emanuela Crăciun.
February 22, 2023 (v1)
Subject: Materials
Keywords: bio-oil, biochar, pyrolysis, vine prunings
The paper aimed at studying the slow pyrolysis of vine pruning waste in a fixed bed reactor and characterizing the pyrolysis products. Pyrolysis experiments were conducted for 60 min, using CO2 as a carrier gas and oxidizing agent. The distribution of biochar and bio-oil was dependent on variations in heat flux (4244−5777 W/m2), CO2 superficial velocity (0.004−0.008 m/s), and mean size of vegetal material (0.007−0.011 m). Relationships among these factors and process performances in terms of yields of biochar (0.286−0.328) and bio-oil (0.260−0.350), expressed as ratio between the final mass of pyrolysis product and initial mass of vegetal material, and final value of fixed bed temperature (401.1−486.5 °C) were established using a 23 factorial design. Proximate and ultimate analyses, FT-IR and SEM analyses, measurements of bulk density (0.112 ± 0.001 g/cm3), electrical conductivity (0.55 ± 0.03 dS/m), pH (10.35 ± 0.06), and water holding capacity (58.99 ± 14.51%) were performed for bioc... [more]
Hybrid Grey Wolf Optimization-Based Gaussian Process Regression Model for Simulating Deterioration Behavior of Highway Tunnel Components
Eslam Mohammed Abdelkader, Abobakr Al-Sakkaf, Nehal Elshaboury, Ghasan Alfalah.
February 22, 2023 (v1)
Keywords: back-propagation artificial neural network, deterioration model, Gaussian process regression, grey wolf optimizer, highway tunnels, maintenance
Highway tunnels are one of the paramount infrastructure systems that affect the welfare of communities. They are vulnerable to higher limits of deterioration, yet there are limited available funds for maintenance and rehabilitation. This state of circumstances entails the development of a deterioration model to forecast the performance condition behavior of critical tunnel elements. Accordingly, this research paper proposes an integrated deterioration prediction model for five highway tunnel elements, namely, cast-in-place tunnel liners, concrete interior walls, concrete portal, concrete ceiling slab, and concrete slab on grade. The developed deterioration model is envisioned in two fundamental components, which are model calibration and model assessment. In the first component, an integrated model of Gaussian process regression and a grey wolf optimization algorithm (GWO-GPR) is introduced for deterioration behavior prediction of highway tunnel elements. In this regard, the grey wolf... [more]
Many-Objective Optimization and Decision-Making Method for Selective Assembly of Complex Mechanical Products Based on Improved NSGA-III and VIKOR
Rongshun Pan, Jiahao Yu, Yongman Zhao.
February 22, 2023 (v1)
Subject: Optimization
Keywords: many-objective optimization, NSGA-III, selective assembly, Taguchi quality loss, VIKOR
In Industry 4.0, data are sensed and merged to drive intelligent systems. This research focuses on the optimization of selective assembly of complex mechanical products (CMPs) under intelligent system environment conditions. For the batch assembly of CMPs, it is difficult to obtain the best combinations of components from combinations for simultaneous optimization of success rate and multiple assembly quality. Hence, the Taguchi quality loss function was used to quantitatively evaluate each assembly quality and the assembly success rate is combined to establish a many-objective optimization model. The crossover and mutation operators were improved to enhance the ability of NSGA-III to obtain high-quality solution set and jump out of a local optimal solution, and the Pareto optimal solution set was obtained accordingly. Finally, considering the production mode of Human−Machine Intelligent System interaction, the optimal compromise solution is obtained by using fuzzy theory, entropy theo... [more]
Research on On-Line Monitoring System of Hydraulic Actuator of Combine Harvester
Ruichuan Li, Yi Cheng, Jikang Xu, Yanchao Li, Xinkai Ding, Shan Zhao.
February 22, 2023 (v1)
Keywords: combine harvester, fault alarm, hydraulic actuating unit, on-line monitoring, the sensor
In view of the complicated hydraulic system, the many driving parts and the great load variation in the combine harvester, and on-line monitoring methods of hydraulic actuating parts such as cutting tables, conveyors and threshing drums were studied. By analyzing the working principle of the hydraulic system of the combine harvester, a mathematical model of the hydraulic system of the combine harvester was established; a simulation model for the fault diagnosis of the hydraulic system of the combine harvester was established based on AMESim. The load signal was introduced to simulate the feeding amount, and the simulation test was carried out. According to the simulation analysis results, the best position of each monitoring point was determined. The on-line monitoring system of the hydraulic actuators of the combine harvester was designed by using LabView, which can collect and display the working parameters of the main working parts of a combine harvester in real time, and alarm the... [more]
Protective Effects of Chlorogenic Acid against Carbon Tetrachloride-Induced Hepatotoxicity in Mice
Yu-Wen Hsu, Ya-Yu Chen, Chia-Fang Tsai.
February 22, 2023 (v1)
Keywords: antioxidant, carbon tetrachloride, chlorogenic acid, hepatoprotective effects
The protective effects of chlorogenic acid (CGA) against liver injury were evaluated by its reduction in carbon tetrachloride (CCl4)-induced hepatic damage in ICR mice. The animals were orally given CGA (60, 100, and 200 mg/kg, respectively) or silymairn (200 mg/kg) daily with 0.3% CCl4 administration (3 mL/kg, dissolved in olive oil) after medicament treatment on the 7th day. Compared with the normal group, CCl4 caused severe impairment in liver according to the evidence of significant reduction in the level of total albumin and expansion (p < 0.05) of the activities in aspartate aminotransferase (AST) and alanine aminotransferase (ALT), cholesterol, triglyceride (TG), and total albumin in serum, decreased the level of glutathione (GSH), and diminished the activities of catalase, superoxide dismutase (SOD), glutathione reductase (GSH-Rd), and glutathione peroxidase (GSH-Px) in liver while increasing the level of hepatic thiobarbituric acid-reactive substances (TBARS). However, oral... [more]
Development of Fuzzy Observer Gain Design Algorithm for Ship Path Estimation Based on AIS Data
Chin-Lin Pen, Wen-Jer Chang, Yann-Horng Lin.
February 22, 2023 (v1)
Keywords: AIS data, fuzzy observer design, ship path estimation, Takagi-Sugeno fuzzy model
This paper develops a Takagi-Sugeno fuzzy observer gain design algorithm to estimate ship motion based on Automatic Identification System (AIS) data. Nowadays, AIS data is widely applied in the maritime field. To solve the problem of safety, it is necessary to accurately estimate the trajectory of ships. Firstly, a nonlinear ship dynamic system is considered to represent the dynamic behaviors of ships. In the literature, nonlinear observer design methods have been studied to estimate the ship path based on AIS data. However, the nonlinear observer design method is challenging to create directly since some dynamic ship systems are more complex. This paper represents nonlinear ship dynamic systems by the Takagi-Sugeno fuzzy model. Based on the Takagi-Sugeno fuzzy model, a fuzzy observer design method is developed to solve the problem of estimating using AIS data. Moreover, the observer gains of the fuzzy observer can be adjusted systemically by a novel algorithm. Via the proposed algorit... [more]
Diels−Alder Cycloadditions of Bio-Derived Furans with Maleimides as a Sustainable «Click» Approach towards Molecular, Macromolecular and Hybrid Systems
Konstantin I. Galkin, Irina V. Sandulenko, Alexander V. Polezhaev.
February 22, 2023 (v1)
Subject: Materials
Keywords: biobased furans, covalent adaptable networks, Diels–Alder reaction, dynamers, dynamic systems, maleimides, plant biomass, platform chemicals
This mini-review highlights the recent research trends in designing organic or organic-inorganic hybrid molecular, biomolecular and macromolecular systems employing intermolecular Diels−Alder cycloadditions of biobased, furan-containing substrates and maleimide dienophiles. The furan/maleimide Diels−Alder reaction is a well-known process that may proceed with high efficiency under non-catalytic and solvent-free conditions. Due to the simplicity, 100% atom economy and biobased nature of many furanic substrates, this type of [4+2]-cycloaddition may be recognized as a sustainable “click” approach with high potential for application in many fields, such as fine organic synthesis, bioorganic chemistry, material sciences and smart polymers development.
Explicit-pH Coarse-Grained Molecular Dynamics Simulations Enable Insights into Restructuring of Intestinal Colloidal Aggregates with Permeation Enhancers
Shakhawath Hossain, Albin Parrow, Aleksei Kabedev, Rosita Carolina Kneiszl, Yuning Leng, Per Larsson.
February 22, 2023 (v1)
Keywords: coarse-graining, explicit pH, intestinal aggregation, molecular dynamics simulations, oral drug delivery, permeation enhancers
Permeation enhancers (PEs) can increase the bioavailability of drugs. The mechanisms of action of these PEs are complex, but, typically, when used for oral administration, they can transiently induce the alteration of trans- and paracellular pathways, including increased solubilization and membrane fluidity, or the opening of the tight junctions. To elucidate these mechanistic details, it is important to understand the aggregation behavior of not only the PEs themselves but also other molecules already present in the intestine. Aggregation processes depend critically on, among other factors, the charge state of ionizable chemical groups, which is affected by the pH of the system. In this study, we used explicit-pH coarse-grained molecular dynamics simulations to investigate the aggregation behavior and pH dependence of two commonly used PEs—caprate and SNAC—together with other components of fasted- and fed-state simulated intestinal fluids. We also present and validate a coarse-grained... [more]
Valorization of Tomato Residues by Supercritical Fluid Extraction
José P. S. Aniceto, Vítor H. Rodrigues, Inês Portugal, Carlos M. Silva.
February 22, 2023 (v1)
Subject: Environment
Keywords: Biomass, carotenoids, supercritical fluid extraction, tocopherols
Tomato processing leads to the production of considerable amounts of residues, mainly in the form of tomato skins, seeds and vascular tissues, which still contain bioactive molecules of interest for food, pharmaceutical and nutraceutical industries. These include carotenoids, such as lycopene and β-carotene, tocopherols and sitosterols, among others. Supercritical fluid extraction is well positioned for the valorization of tomato residues prior to disposal, because it remains an environmentally safe extraction process, especially when using carbon dioxide as the solvent. In this article, we provide an extensive literature overview of the research on the supercritical fluid extraction of tomato residues. We start by identifying the most relevant extractables present in tomatoes (e.g., lycopene) and their main bioactivities. Then, the main aspects affecting the extraction performance are covered, starting with the differences between tomato matrixes (e.g., seeds, skins and pulp) and poss... [more]
A Sustainable Process to Produce Manganese and Its Alloys through Hydrogen and Aluminothermic Reduction
Jafar Safarian.
February 22, 2023 (v1)
Keywords: aluminothermic, CO2 emission, energy consumption, ferromanganese, Hydrogen, manganese, reduction, sustainable
Hydrogen and aluminum were used to produce manganese, aluminum−manganese (AlMn) and ferromanganese (FeMn) alloys through experimental work, and mass and energy balances. Oxide pellets were made from Mn oxide and CaO powder, followed by pre-reduction by hydrogen. The reduced MnO pellets were then smelted and reduced at elevated temperatures through CaO flux and Al reductant addition, yielding metallic Mn. Changing the amount of the added Al for the aluminothermic reduction, with or without iron addition led to the production of Mn metal, AlMn alloy and FeMn alloy. Mass and energy balances were carried out for three scenarios to produce these metal products with feasible material flows. An integrated process with three main steps is introduced; a pre-reduction unit to pre-reduce Mn ore, a smelting-aluminothermic reduction unit to produce metals from the pre-reduced ore, and a gas treatment unit to do heat recovery and hydrogen looping from the pre-reduction process gas. It is shown that... [more]
The Prediction of Essential Medicines Demand: A Machine Learning Approach Using Consumption Data in Rwanda
Francois Mbonyinshuti, Joseph Nkurunziza, Japhet Niyobuhungiro, Egide Kayitare.
February 22, 2023 (v1)
Keywords: consumption data, essential medicines, forecasting models, health supply chain, Machine Learning, Rwanda
Today’s global business trends are causing a significant and complex data revolution in the healthcare industry, culminating in the use of artificial intelligence and predictive modeling to improve health outcomes and performance. The dataset, which was referred to is based on consumption data from 2015 to 2019, included approximately 500 goods. Based on a series of data pre-processing activities, the top ten (10) essential medicines most used were chosen, namely cotrimoxazole 480 mg, amoxicillin 250 mg, paracetamol 500 mg, oral rehydration salts (O.R.S) sachet 20.5 g, chlorpheniramine 4 mg, nevirapine 200 mg, aminophylline 100 mg, artemether 20 mg + lumefantrine (AL) 120 mg, Cromoglycate ophthalmic. Our study concentrated on the application of machine learning (ML) to forecast future trends in the demand for essential drugs in Rwanda. The following models were created and applied: linear regression, artificial neural network, and random forest. The random forest was able to predict 10... [more]
Detection of Contaminants in Hydrogen Fuel for Fuel Cell Electrical Vehicles with Sensors—Available Technology, Testing Protocols and Implementation Challenges
Karine Arrhenius, Thomas Bacquart, Karin Schröter, Martine Carré, Bruno Gozlan, Claire Beurey, Claire Blondeel.
February 22, 2023 (v1)
Keywords: FCEV, hydrogen quality, sensors, testing protocols
Europe’s low-carbon energy policy favors a greater use of fuel cells and technologies based on hydrogen used as a fuel. Hydrogen delivered at the hydrogen refueling station must be compliant with requirements stated in different standards. Currently, the quality control process is performed by offline analysis of the hydrogen fuel. It is, however, beneficial to continuously monitor at least some of the contaminants onsite using chemical sensors. For hydrogen quality control with regard to contaminants, high sensitivity, integration parameters, and low cost are the most important requirements. In this study, we have reviewed the existing sensor technologies to detect contaminants in hydrogen, then discussed the implementation of sensors at a hydrogen refueling stations, described the state-of-art in protocols to perform assessment of these sensor technologies, and, finally, identified the gaps and needs in these areas. It was clear that sensors are not yet commercially available for all... [more]
Methanol Steam Reforming on Bimetallic Catalysts Based on In and Nb Doped Titania or Zirconia: A Support Effect
Alexandra Lytkina-Payen, Natalya Tabachkova, Andrey Yaroslavtsev.
February 22, 2023 (v1)
Keywords: bimetallic catalyst, doped titania, hydrogen production, methanol steam reforming, support effect
Methanol steam reforming (MSR) is considered an effective method for hydrogen storage and to generate high-quality hydrogen for fuel cells. In this work, a comprehensive investigation of the methanol steam reforming process using a bimetallic Pt−Rh and Cu−Ni based on different oxide supports is presented. Highly dispersed titania and zirconia doped with indium and niobium ions were synthesized by sol−gel method. The effect of the nature and quantity of the dopant cation (In, Nb) on the catalytic performance of titania supported metal catalysts was investigated. The conclusions obtained show a significant effect of both the metal alloy and the oxide support nature on the activity and selectivity of the methanol steam reforming process. Pt−Rh alloy catalyst shows higher hydrogen yield, but its selectivity in the MSR process is lower than for the catalysts containing the Cu0.8-Ni0.2 alloy. Heterovalent indium doping of titania leads to the catalytic activity increase. It was suggested tha... [more]
Cryoconcentration by Centrifugation−Filtration: A Simultaneous, Efficient and Innovative Method to Increase Thermosensitive Bioactive Compounds of Aqueous Maqui (Aristotelia chilensis (Mol.) Stuntz) Extract
José Miguel Bastías-Montes, Carla Vidal-San-Martín, Yanara Tamarit-Pino, Ociel Muñoz-Fariña, Olga García-Figueroa, Roberto Quevedo-León, Zhao-Jun Wei, Xingang Lv, Carlos L. Cespedes-Acuña.
February 22, 2023 (v1)
Subject: Biosystems
Keywords: Aristotelia chilensis, centrifugation–filtration, cryoconcentration, high efficiency, maqui, simultaneous process
Maqui (Aristotelia chilensis (Mol.) Stuntz) is a Chilean berry rich in antioxidants, which are mostly found in the pulp and skin of the fruit. The objective was to evaluate the cryoconcentration process by centrifugation−filtration as a simultaneous, efficient, and innovative method to increase the content of thermosensitive bioactive compounds of aqueous maqui extract. Cryoconcentration separated the concentrated solute from the aqueous maqui extract with an efficiency of more than 95%; it increased the content of total polyphenols and total anthocyanins and antioxidant capacity by 280%, 573%, and 226%, respectively. Although the concentrates obtained by evaporation at 50, 70, and 80 °C increased the content of bioactive compounds, they did so in a lower percentage than the cryoconcentrate. Furthermore, cyanidin 3,5-diglucoside was degraded at 70 and 80 °C. In conclusion, cryoconcentration by centrifugation−filtration as a simultaneous process efficiently separates the solutes from th... [more]
Fundamental Study on Ammonia Low-NOx Combustion Using Two-Stage Combustion by Parallel Air Jets
Kenta Kikuchi, Ryuichi Murai, Tsukasa Hori, Fumiteru Akamatsu.
February 22, 2023 (v1)
Keywords: ammonia, burner, NOx, two-stage combustion
Ammonia, which has advantages over hydrogen in terms of storage and transportation, is increasingly expected to become a carbon-free fuel. However, the reduction of fuel NOx emitted from ammonia combustion is an unavoidable challenge. There is the report that two-stage combustion with parallel independent jets could achieve Low-NOx combustion under ammonia/methane co-firing conditions. In order to further improve NOx reduction, we experimentally evaluated the effects of secondary air nozzle parameters, such as nozzle diameter and nozzle locations, on combustion characteristics in two-stage combustion of ammonia/natural gas co-firing using parallel independent jets. As a result of the experiments under various secondary air nozzle conditions, it was found that under the conditions where NOx was significantly reduced, the peak temperature in the furnace was observed at 300−500 mm in the axial direction from the burner, and then the temperature decreased toward the downstream of the furna... [more]
Special Issue “Applications of Biosorption in Wastewater Treatment”
José Enrique Torres Vaamonde.
February 22, 2023 (v1)
Subject: Environment
The interest in the use of biosorption for the elimination of pollutants is because this technique is an efficient and environmentally friendly process, constituting an alternative to the so-called conventional treatment processes [...]
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