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Records Added in April 2023
Records added in April 2023
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Showing records 301 to 325 of 9292. [First] Page: 9 10 11 12 13 14 15 16 17 Last
Evaluation of Crude Oil Wax Dissolution Using a Hydrocarbon-Based Solvent in the Presence of Ionic Liquid
Muhammad Rahmat Syafiq Zainal Abidin, Mohd Hilmi Noh, Muhammad Moniruzzaman, Masahiro Goto
April 28, 2023 (v1)
Keywords: crude oil wax, gas condensate, hydrocarbon solvent, ionic liquid
The current alternative of using aromatic-based wax soak solvents has been found to be hazardous and imposes a high cost on field expenditures. These solvents are widely used in the oil and gas industry to soften up wax before the pigging process. However, their impacts on the environment are quite concerning. Plus, they also impose hazardous exposure and are found to be damaging to both plastic and rubber hoses. To replace the current alternative with other hydrocarbon-based wax soak solvents, ionic liquids were found to have the capability to increase the solvent power capabilities and the efficiency of wax soak solvent in dissolving heavy crude oil. To optimise the application of hydrocarbon solvents and ionic liquid in wax dissolution, the affinity of ionic liquids in three solvents was studied. The solvents were condensate, ethyl acetate, and xylene. It was found that from four types of ionic liquids tested, only BMIMCL and HMIMBr were miscible in all three of the solvents used. D... [more]
Determination of the Antioxidant and Antiproliferative Properties of Pomegranate Peel Extract Obtained by Ultrasound on HCT-116 Colorectal Cancer Cell Line
Christie Habchi, Adnan Badran, Mortada Srour, Anis Daou, Elias Baydoun, Kamar Hamade, Akram Hijazi
April 28, 2023 (v1)
Subject: Biosystems
Keywords: antioxidant, antiproliferative, colorectal cancer, maceration, pomegranate, ultrasound assisted extraction
Colorectal cancer (CRC) is one of the most common cancers in the world. When treating patients, therapeutic agents have side effects; hence, the use of natural compounds found in medicinal plants including pomegranate. Ultrasound assisted extraction (UAE) is a new technique evolving to the detriment of traditional methods such as maceration. In this study, we investigated the antioxidant and anticancer effect of pomegranate peel extracts obtained by maceration and UAE at three different ultrasonic power levels (P1 = 10 W; P2 = 50 W; P3 = 100 W) on HCT-116 colorectal cancer cells. Phytochemical screening highlighted the presence of primary and secondary metabolites in pomegranate peels. In addition, the ethanolic extract obtained by UAE at 50 W was shown to be the most concentrated in phenolic and flavonoid compounds and have the most powerful antioxidant activity, which reached a maximum activity of 92% as determined by DPPH test. Similarly, the MTT cell viability test showed that the... [more]
Complicated Time-Constrained Project Scheduling Problems in Water Conservancy Construction
Song Zhang, Xiaokang Song, Liang Shen, Lichun Xu
April 28, 2023 (v1)
Keywords: Genetic Algorithm, project scheduling, resource-constrained, water conservancy
Water conservancy project scheduling is an extension to the classic resource-constrained project scheduling problem (RCPSP). It is limited by special time constraints called “forbidden time windows” during which certain activities cannot be executed. To address this issue, a specific RCPSP model is proposed, and an approach is designated for it which incorporates both a priority rule-based heuristic algorithm to obtain an acceptable solution, and a hybrid genetic algorithm to further improve the quality of the solution. In the genetic algorithm, we introduce a new crossover operator for the forbidden time window and adopt double justification and elitism strategies. Finally, we conduct simulated experiments on a project scheduling problem library to compare the proposed algorithm with other priority-rule based heuristics, and the results demonstrate the superiority of our algorithm.
Single-Cell Techniques in Environmental Microbiology
Yongping Shan, Yuting Guo, Wentao Jiao, Ping Zeng
April 28, 2023 (v1)
Keywords: flow cytometry, identification, isolation, observation, single-cell techniques
Environmental microbiology has been an essential part of environmental research because it provides effective solutions to most pollutants. Hence, there is an interest in investigating microorganism behavior, such as observation, identification, isolation of pollutant degraders, and interactions between microbial species. To comprehensively understand cell heterogeneity, diverse approaches at the single-cell level are demanded. Thus far, the traditional bulk biological tools such as petri dishes are technically challenging for single cells, which could mask the heterogeneity. Single-cell technologies can reveal complex and rare cell populations by detecting heterogeneity among individual cells, which offers advantages of higher resolution, higher throughput, more accurate analysis, etc. Here, we overviewed several single-cell techniques on observation, isolation, and identification from aspects of methods and applications. Microscopic observation, sequencing identification, flow cytome... [more]
Corn Extrudates Enriched with Health-Promoting Ingredients: Physicochemical, Nutritional, and Functional Characteristics
Alina Culețu, Iulia Elena Susman, Mihaela Mulțescu, Șerban Eugen Cucu, Nastasia Belc
April 28, 2023 (v1)
Subject: Biosystems
Keywords: antioxidant capacity, condiments, corn, extrudates, glycemic index, phenolic compounds, plants, protein sources
The objective of this study was to evaluate the effects of different types of powder additions on the properties of corn extrudates. The following ingredients, which are good sources of bioactive compounds, were used to substitute corn flour: legume protein sources (2% pea, 5% broccoli, and 5% lucerne), plants (15% beetroot and 15% rosehip), and condiments (2% chili, 2% turmeric, 2% paprika, and 2% basil). The total polyphenolic content (TPC) and antioxidant activity (AA) increased when the corn flour was replaced with the different types of ingredients. The highest TPC was found for rosehip followed by the beet, basil, and broccoli additions. Compared to the raw formulations, all the extrudates, except the rosehip extrudate, showed a decrease in the TPC ranging from 11 to 41%, with the smallest loss (11%) occurring for basil and the highest loss (41%) occurring for the control extrudate, respectively. The same observation was recorded for the AA. For the extrudate enriched with rosehi... [more]
Antimicrobial and Photocatalytic Activities of Selenium Nanoparticles Synthesized from Elaeagnus indica Leaf Extract
Dhatchanamoorthi Indhira, Arumugam Aruna, Krishnamoorthy Manikandan, Mohammed F. Albeshr, Abdulwahed Fahad Alrefaei, Ramachandran Vinayagam, Arumugam Kathirvel, Selvaraj Ranjith Priyan, Govindan Suresh Kumar, Ramalingam Srinivasan
April 28, 2023 (v1)
Subject: Materials
Keywords: antimicrobials, Elaeagnus indica, green synthesis, photocatalytic activity, Se NPs
Selenium nanoparticles (Se NPs) have recently received much interest due to their low toxicity, high bioavailability, and wide applications. This study synthesized Se NPs using selenious acid as a starting material and leaf extract from Elaeagnus indica as a reducing agent. Spectroscopic and electron microscopy investigations have demonstrated the production of aggregated amorphous Se NPs with phytochemicals. Furthermore, the reduction of selenious acid into Se NPs by phytochemicals present in the leaf extract of E. indica was confirmed in a prominent band at 269 nm in the UV-visible spectrum. The biosynthesized selenium nanoparticles have a 10−15 nm particle size distribution. The agar well diffusion assay exhibited remarkable dose-dependent, wide-spectrum antimicrobial efficacy of the Se NPs against all the tested microorganisms. Moreover, the lowest minimum inhibitory concentration (10 µg/mL) was noted against Salmonella Typhimurium and Fusarium oxysporum. The prepared Se NPs degrad... [more]
Establishment of a Research Focus on Resilient Sustainable Climate Neutral Agricultural Production—Resilient Farming Initiative
Alexander Uhl, Axel Schmidt, Martin Tegtmeier, Andreas Wenzel, Frank Beneke, Jochen Strube
April 28, 2023 (v1)
Keywords: agri-photovoltaics, cascade utilization, circular economy, climate neutrality, cultivation and harvesting technology, digitalization, energy and resource efficiency, resilience, robotics, waste valorization
Efficient and sustainable agricultural production is a pivotal factor in meeting the nutritional needs of an expanding global population. However, it is imperative to optimize national, regional and local effectiveness to support government initiatives towards climate neutrality and resilience, while simultaneously ensuring economic viability for farmers. A significant reduction in the cost of goods must be accompanied by a decrease in their global warming potential contribution to maintain competitiveness in the world market. As such, it is necessary to adopt practices that enhance productivity while minimizing environmental impacts. This paper discusses potential solutions for the sustainable enlargement of botanical product portfolios towards essential oil products and natural extracts for value-added products, such as natural pharmaceuticals, cosmetics, agrochemicals and materials by direct waste valorization. Contributions from the fields of automation and digitalization provide t... [more]
Design and Modelling of Heat-Coupled Storage System with High- and Low-Pressure Bypass: Electrothermal Characteristics and Peak Regulating Performance
Han Yang, Sun Tao, Ma Honghe
April 28, 2023 (v1)
Keywords: Aspen Plus, heat-coupled storage system, high- and low-pressure bypass, peak regulation
To achieve a balance between supply and demand during cogeneration system operation, it is necessary to improve the peak regulation capacity and regulatory flexibility of the unit. Considering the excellent performance of energy storage systems, a heat-coupled storage system with high- and low-pressure bypass is proposed to increase peak regulation capacity. Employing a 300 MW heating unit as the research object, thermal system models of a traditional-pumping steam-heating system, a high- and low-pressure bypass heating system, and a coupled system were built using Aspen Plus software. The electric heating characteristics of the three systems, as well as the peak regulation capacity and peak regulation depth of the coupled system, were analysed under different storage and heat release loads. Results indicate that the high- and low-voltage bypass system and the coupled system both improve the peak capacity and control flexibility of the unit. Moreover, the coupled system has a greater i... [more]
Influence of Estimators and Numerical Approaches on the Implementation of NMPCs
Fernando Arrais Romero Dias Lima, Ruan de Rezende Faria, Rodrigo Curvelo, Matheus Calheiros Fernandes Cadorini, César Augusto García Echeverry, Maurício Bezerra de Souza Jr, Argimiro Resende Secchi
April 28, 2023 (v1)
Keywords: CEKF, estimators, Nonlinear Model Predictive Control, Numerical Methods, orthogonal collocation
Advanced control strategies, together with state-estimation methods, are frequently applied to nonlinear and complex systems. It is crucial to understand which of these are the most efficient methods for the best use of these approaches in a chemical process. In the current work, nonlinear model predictive control (NMPC) approaches were developed that considered three numerical methods: single shooting (SS), multiple shooting (MS), and orthogonal collocation (OC). Their performance was compared against the Van de Vusse reactor benchmark while considering set-point changes, unreachable set-point, disturbances, and mismatches. The results showed that the NMPC based on OC presented less computational cost than the other approaches. The extended Kalman filter (EKF), constrained extended Kalman filter (CEKF), and the moving horizon estimator (MHE) were also developed. The estimators’ performance was compared for the same benchmark by considering the computational cost and the mean squared e... [more]
Design and Optimization of the Training Device for the Employment of Hydraulic Rescue Tools in Traffic Accidents
Michal Ballay, Bohuš Leitner, Lenka Jakubovičová
April 28, 2023 (v1)
Subject: Optimization
Keywords: beam element, design, experiment, FEM analysis, firefighters’ units, hydraulic rescue tools, Optimization, training device prototype
This paper is concerned with the design and structural optimization of a training device for operators of a hydraulic rescue tool employed during traffic accidents, in conjunction with the improvement of the technical procedures used in such situations. Changes in the design process and subsequent production in the motor industry frequently result in an increased impact resistance of the used structural components. This applies, also, to extrication works and frequently used technical equipment. This paper presents its findings on the design process for the prototype of a training device designed for the extrication cutting drill with the assistance of a hydraulic rescue tool. The primary part of the research was dedicated to structural optimization; therefore, parameter dimensioning of the training device’s prototype was implemented. The device’s mechanical resistance, sturdiness, and stability during the implementation of hydraulic tools were also taken into account. A secondary part... [more]
Particle Deposition Pattern on an Automotive Diesel Filter Using an Eulerian Probability Density Function Method
Luis Valiño, Radu Mustata, Juan Hierro, Juan Luis Hernández, María José García, Carlos Blasco, Yi-Tung Chen, Lung-Wen Chen, Prosun Roy
April 28, 2023 (v1)
Keywords: Eulerian probability density function, filter, particle size distribution, two-phase flows
A full 3D numerical simulation of the two-phase flow made up of (bio)diesel and particles, has been carried out to reproduce the deposition pattern of particles in a BOSCH automotive filter. From a probability density function (PDF), a simple Eulerian-Eulerian two-phase model is proposed for diesel and particles. The proposed formulation allows for a detailed description of the relationship between the velocity and size of the particles. A Brinkman-Darcy approximation has been considered for the flow through the filtering paper and is proved to be sufficient for the typical filter working conditions. The new tool is able to reproduce the deposition pattern shown by the used filters.
Pozzolanic Reactivity and Hydration Products of Cementitious Material Prepared Using Molybdenum Tailings
Biyao Geng, Zongwen Wang, Shihu Shi, Kun Wang, Jianxun Fu, Zhenjiang Wen, Xiaogang Guo
April 28, 2023 (v1)
Subject: Materials
Keywords: C-S-H gel, ettringite, hydration, molybdenum tailings, pozzolanic reaction
This study aimed to examine the pozzolanic reactivity and hydration products of cementitious materials prepared using molybdenum tailings. During the grinding process, the particle size of molybdenum tailings decreases continuously between 15 and 60 min, and the specific surface area increases from 367 to 932.4 m2/kg. For this, samples were prepared using 91 wt% milled molybdenum tailings, 3 wt% natural gypsum, 6 wt% calcium hydroxide, and a mixture of 0.3 wt% water reducer and water:binder at a ratio of 0.2. The phase transformation and hydration products of molybdenum tailings were analyzed using a compressive strength tester, X-ray diffraction, scanning electron microscopy, and infrared radiation. The 3-, 7-, and 28-day compressive strengths of the samples were found to be 1.67, 3.17, and 3.83 MPa, respectively, which shows that the molybdenum tailings have pozzolanic reactivity. Other testing means showed that the molybdenum tailings are mainly composed of ettringite and C-S-H gel... [more]
The Use of Chitosan for Flocculation Recovery of Bacillus Biomass Grown on Dairy and Wine Industry Effluents
Selena Dmitrović, Nataša Lukić, Ivana Pajčin, Vanja Vlajkov, Jovana Grahovac, Aleksandar Jokić
April 28, 2023 (v1)
Keywords: Bacillus sp., chitosan, flocculation, food industry wastewaters
The downstream processing of efficient biomass-based microbial biopesticides is heavily reliant on obtaining the largest concentration of viable cells in the most cost-effective manner. The goal of this research was to assess the ability of chitosan flocculation to recover bacterial Bacillus sp. BioSol021 biomass from the broth after biological treatment of wastewaters from the dairy and wine industries. Second-order factorial design models were used to estimate the effect of chitosan concentration and mixing speed on flocculation efficiency, settling velocity, and antimicrobial activity against Aspergillus flavus, i.e., inhibition zone diameter. Response surface methodology was followed by multi-objective optimization by applying the desirability function (DF) and genetic algorithm (GA). The optimum values for flocculation efficiency, settling velocity, and inhibition zone diameter for cheese whey effluent were 88%, 0.10 mm/s, and 51.00 mm, respectively. In the case of winery flotatio... [more]
Gas-Driven Endoscopic Robot for Visual Inspection of Corrosion Defects Inside Gas Pipelines
Jin Fang, Jun Xiang, Li Ma, Hao Liu, Chenxiang Wang, Shan Liang
April 28, 2023 (v1)
Keywords: corrosion detection, endoscopic robot, gas-driven robot, pipelines
The internal inspection of corrosion in large natural gas pipelines is a fundamental task for the prevention of possible failures. Photos and videos provide direct proof of internal corrosion defects. However, the implementation of this technique is limited by fast robot motion and poor lighting conditions, with high-quality images being key to its success. In this work, we developed a natural gas-driven pipeline endoscopic robot (GDPER) for the visual inspection of the inner wall surfaces of pipelines. GDPER consists of driving, odometer, and vision modules connected by universal joints. It is designed to work in a 154 mm gas-pressurized pipeline up to a maximum of 6 MPa, allowing it to smoothly pass through bends and cross-ring welds at a maximum speed of 3 m/s using gas pressure driving. Test results have shown that HD MP4 video files can be obtained, and the location of defects on the pipelines can be detected by intelligent video image post-processing. The gas-driven function enab... [more]
Experimental and Simulation Study on the Direct Contact Condensation of Saturated Steam on Moving Droplets at Sub-Atmospheric Pressure
Yuanlin Jing, Yiping Wang, Qunwu Huang
April 28, 2023 (v1)
Keywords: direct contact condensation, droplets, heat transfer coefficient, numerical simulation, saturated steam
The recovery of low-temperature steam is of great significance to the effective utilization of energy. Direct contact condensation (DCC) technology is an effective heat recovery method with a low initial investment. An evaluation of the direct contact condensation heat transfer technology of water droplets and low-temperature saturated steam (at an absolute pressure of 7.3−19.9 kPa) was performed using both experimental and computational approaches. In the experiment, an experimental device based on the weighing method was set up, and the direct contact heat transfer process between droplets with a normalized diameter of less than 21.7 and saturated pure steam at 40−60 °C was experimentally investigated. The transient condensation efficiency and heat transfer coefficient were calculated by the real-time mass variation. The rapid condensation stage was classified to discuss the effects of initial droplet diameter, pressure, temperature, and mass flow rate on the heat transfer process. A... [more]
Short Review of Self-Powered Nitrogen Removal via Abiotic Electrochemical Catalysis
Binbin Yu, Wei Xu, Yanxian Jin
April 28, 2023 (v1)
Subject: Materials
Keywords: abiotic electrocatalysts, Fuel Cells, nitrogen removal, self-power
Microbial nitrification and denitrification are efficient technologies for the treatment of nitrogen-containing wastewater. However, these biotic technologies are inapplicable for the treatment of toxic substances such as heavy metals, polyaromatic hydrocarbons, adsorbable organic halogens, and polychlorinated biphenyls, which have an inhibitory effect on microbial metabolism. It is therefore necessary to develop abiotic nitrogen removal technology with comparable cost efficiency. Nitrogen contaminants are promising indirect fuel sources. The integration of electrocatalysis energy conversion with nitrogen contaminants could drive an entire electrochemical system to obtain nitrogen removal in a self-powered fashion. Research advances in the development of fuel cells have corroborated their promising application for nitrogen removal. This work aims to review the most recent advances in the utilization of ammonia and nitrate as fuels for self-powered nitrogen removal and demonstrate how c... [more]
Mixed Seeds of Oat and Vetch Based on DEM-Fluent Coupling Motion Simulation in a Venturi Tube
Yangyang Liao, Yong You, Yunting Hui, Xuening Zhang, Decheng Wang
April 28, 2023 (v1)
Keywords: DEM-CFD coupling approach, gas–solid two-phase flow, mixed seeding metering device, seed motion, venturi tube
The gas−solid flow of mixed seeds of oat and vetch in the air-blowing venturi tube was simulated numerically by means of a coupling approach of the discrete element method (DEM) and computational fluid dynamics (CFD). In the gas−solid coupling model, EDEM software was used to depict the discrete particle phase, and ANSYS Fluent software was used to describe the continuous gas phase. The effects of the seed entry angle and inlet air velocity on the uniformity of mixed seed supply were studied and analyzed from the angle of airflow field variation and mixed seeds movement characteristics. The simulation results showed that the seeding angle has a great influence on the seed movement in the tube and affects the pressure and velocity gradient of the airflow field. If the seed insertion angle is too large, the number of collisions between the seed and the tube wall will increase, and the phenomenon of seeds retention and disordered jumping will occur. The inlet air velocity mainly affects t... [more]
An Investigation into the Metabolic Differences between Conventional and High Seeding Density Fed-Batch Cell Cultures by Applying a Segmented Modeling Approach
Teresa Laura Krumm, Alireza Ehsani, Jochen Schaub, Fabian Stiefel
April 28, 2023 (v1)
Keywords: feeding optimization, intensified fed-batch, segmented modeling
The conventional fed-batch process characterized by a low titer currently challenges pharmaceutical development. Process optimization by applying a perfusion process in the pre-stage and subsequent production phase at a high seeding density (HSD) can meet this challenge. In this study, we employed a simplified approach based on measured experiments, namely segmented modeling, to systematically analyze an HSD fed-batch process compared to a standard process. A comparison indicated that the metabolic phases of HSD processes are not only shifted in time, but metabolite trends show an altered metabolism. In an extended study, we integrated the intracellular fluxes determined by a metabolic flux analysis into the segmented modeling approach. Compared to using only extracellular rates, similar phases are identified, and this highlights the reliability of phase identification modeling using extracellular rates only. Furthermore, the segmented linear regression approach is used to create a mod... [more]
A Novel Ultra Local Based-Fuzzy PIDF Controller for Frequency Regulation of a Hybrid Microgrid System with High Renewable Energy Penetration and Storage Devices
Ahmed H. Yakout, Kareem M. AboRas, Hossam Kotb, Mohammed Alharbi, Mokhtar Shouran, Bdereddin Abdul Samad
April 28, 2023 (v1)
Keywords: fuzzy control, load frequency control, marine predator algorithm, PID, Renewable and Sustainable Energy, ultra-local control
A new ultra-local control (ULC) model and two marine predator algorithm (MPA)-based controllers; MPA-based proportional-integral-derivative with filter (PIDF) and MPA-based Fuzzy PIDF (FPIDF) controllers; are combined to enhance the frequency response of a hybrid microgrid system. The input scaling factors, boundaries of membership functions, and gains of the FPIDF con-troller are all optimized using the MPA. In order to further enhance the frequency response, the alpha parameter of the proposed ULC model is optimized using MPA. The performance of the pro-posed controller is evaluated in the microgrid system with different renewable energy sources and energy storage devices. Furthermore, a comparison of the proposed MPA-based ULC-PIDF and ULC-FPIDF controllers against the previously designed controllers is presented. Moreover, a vari-ety of scenarios are studied to determine the proposed controller’s sensitivity and robustness to changes in wind speed, step loads, solar irradiance, and... [more]
Effect of Drying Pretreatment on Cellulolytic Enzymatic Hydrolysis of Lignin from Napier Grass
Syazmi Zul Arif Hakimi Saadon, Noridah Binti Osman
April 28, 2023 (v1)
Keywords: cellulase, enzymatic hydrolysis, lignin, Napier grass, pretreatment
Biomass can be a viable supplement and alternative to non-renewable sources of fuel and chemicals. Lignin is an important part of biomass sources which can be used in various chemical and fuel industries. This study explores the pretreatment of lignin from Napier grass using thermal and physical means, as well as extraction of lignin via cellulolytic enzymatic hydrolysis to determine the optimum condition for feedstock pretreatment. Napier grass parts under various drying conditions and particle sizes were treated with enzymes. Moisture analysis, FTIR spectroscopy, UV−Vis analysis, and Klason lignin were carried out to analyze the moisture, functional group, and yield of lignin. Moisture content of the samples were inversely proportional to the drying conditions. The FTIR result showed lower peak intensity for higher drying conditions, while ball-milling showed less reduction in peak intensity. More Klason lignin was extracted under higher drying conditions. The yield of cellulolytic e... [more]
The Influences of Emulsification Variables on Emulsion Characteristics Prepared through the Phase Inversion Temperature Method as Engine Fuel
Cherng-Yuan Lin, Keng-Hung Lin, Hsuan Yang
April 28, 2023 (v1)
Keywords: electrical conductance, emulsification stability, emulsification variables, nonionic surfactant, phase inversion temperature
The effects of emulsification variables, such as surfactant type and heating/cooling emulsion processes, on the emulsification characteristics of silicone oil’s emulsions prepared by the phase inversion temperature method were investigated in this study. The water-in-oil (W/O) emulsions have been widely applied to enhance burning efficiency and reduce both pollutant emissions and fuel consumption. The silicone oil was emulsified with de-ionized water with the assistance of nonionic surfactants to form oil-in-water (O/W) emulsions. The hydrophilic−lipophilic balance (HLB) value of the Span 80 and Tween 20 surfactant mixture was set equal to 10 based on their weight proportions and the respective HLB values of the two surfactants. The experimental results show that the emulsions with the Span 80/Tween 20 surfactant mixture appeared to have a higher phase inversion temperature and a larger electrical conductance. On the other hand, it has a lower emulsification stability and a narrower ra... [more]
Stability Analysis Method for Initial Support Structure of Tunnel in Swelling Loess
Jianxun Wu, Jian Jiang, Zhanlin Li, Yonghao Yang, Zhenkun Hou, Zhongxing Sun, Xing Gong
April 28, 2023 (v1)
Keywords: initial support structure, softening, stability, swelling force, swelling loess
The stability of tunnel is greatly affected by the changes in volume and strength of swelling loess caused by humidification. Quantitative reflection of the influence of humidification on stability in mechanical model has important engineering significance for the design of support structures. Based on the fact that parameters related to swelling and strength are functions of water content, the water content was introduced into the classical surrounding rock−support model, and a safety factor was employed as the index of stability. Thus, a stability analysis framework of swelling loess tunnel was established by considering the swelling and softening of swelling loess. In an engineering case, the theoretical models presented in this paper were introduced to investigate the change rules of surrounding rock deformation and tunnel safety factor, as well as the sensitivity of the safety factor of tunneling in swelling loess. Analysis results showed that the change rules of surrounding rock... [more]
A Square Wave Alternating Current Preheating with High Applicability and Effectiveness of Preventing Lithium Plating
Guanlin Liu, Zeping Zhang, Jinke Gong, Qiong Li, Yun Zhou, Hongfu Zou
April 28, 2023 (v1)
Keywords: alternating current preheating, lithium-plating, square wave, temperature-adaptive
Alternating current preheating (ACP) of lithium-ion batteries has the advantage of a high heating rate while inhibiting lithium plating. Two strategies based on terminal voltage control and full battery impedance control were proposed to simplify the ACP implementation. However, such strategies either severely compromise the preheating rate or induce non-negligible lithium plating. To maximize the preheating rate while ensuring no lithium plating, an ACP method based on anode potential control is developed using a square wave alternating current. The operation boundaries of lithium plating prevention, in terms of frequency and maximum permissible current amplitude, are determined using the anode potential and impedance. Their effectiveness in preventing lithium plating is validated by repeating 800 cycles of preheating. By applying the operation boundaries, a temperature-adaptive preheating is found to be able to speed up the preheating rate with higher frequency, smaller temperature i... [more]
Effect of Rosehip Powder Addition on Dough Extensographic, Amylographic and Rheofermentographic Properties and Sensory Attributes of Bread
Nicoleta Vartolomei, Maria Turtoi
April 28, 2023 (v1)
Keywords: amylograph, ascorbic acid, bread, dough, extensograph, rheofermentometer, rosehip powder, sensory attributes, wheat flour
One of the improvers used in breadmaking is ascorbic acid (AA), a chemical compound that strengthens the dough and extends the shelf life of bread. This work investigates the suitability of replacing the synthetic AA with rosehip powder (Rp) rich in this bioactive compound. Thus, a comprehensive study of wheat flour (WF) replaced with 0.5−2.5% w/w Rp regarding the extensographic, amylographic and rheofermentographic properties of dough and sensory attributes of bread was performed. WF without RP or AA addition of 2 mg/100 g was used as a control. A sample with an AA addition of 2 mg/100 g was also used. The Rp addition positively influenced the extensographic, amylographic and rheofermentographic properties of the dough. The dough resistance to extension, R, in Brabender Units (BU), increased from 330 ± 1.41 BU (control) to 995 ± 1.41 BU (2.5% w/w Rp) for a resting time of 90 min. The gelatinization temperature of the dough increased from 61.0 °C (control) to 62.9 °C (2.5% w/w Rp). The... [more]
A Novel High-Voltage Gain Step-Up DC−DC Converter with Maximum Power Point Tracker for Solar Photovoltaic Systems
Rashid Ahmed Khan, Hwa-Dong Liu, Chang-Hua Lin, Shiue-Der Lu, Shih-Jen Yang, Adil Sarwar
April 28, 2023 (v1)
Keywords: high-voltage gain step-up DC–DC converter, hill climbing algorithm, maximum power point tracker, non-isolated topology
In order to generate electricity from solar PV modules, this study proposed a novel high-voltage gain step-up (HVGSU) DC−DC converter for solar photovoltaic system operation with a maximum power point (MPP) tracker. The PV array can supply power to the load via a DC−DC converter, increasing the output voltage. Due to the stochastic nature of solar energy, PV arrays must use the MPPT control approach to function at the MPP. This study suggests a novel HVGSU converter that uses the primary boost conversion cell and combines switched capacitors and voltage multiplier cells. The proposed topology is upgradeable for high-voltage gain step-up and can be incorporated as well. A clamp circuit reuses the energy that leaks out so that the switch voltage stress and power loss are kept to a minimum. One thing that makes it stand out is that the voltage stress on the diodes and switch stays low and constant even as the duty cycle changes. Additionally, the inductor greatly reduces the diodes’ rever... [more]
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