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Showing records 1785 to 1809 of 43292. [First] Page: 1 69 70 71 72 73 74 75 76 77 Last
Optimizing Accumulator Performance in Hydraulic Systems through Support Vector Regression and Rotational Factors
Zilong Xu, Juan Zhou, Hu Chen, Bo Xu, Zhengxiang Shen.
June 5, 2024 (v1)
Keywords: error compensation, millimeter-wave radar, neural network, piston accumulator.
The piston-type accumulator is an energy storage device in hydraulic−pneumatic systems, playing a significant role in industries such as petrochemicals, heavy machinery, and steel metallurgy. The displacement parameters of the piston-type accumulator are vitally important for fault diagnosis and early warning in hydraulic systems. Traditional displacement measurement methods cannot meet the requirements of the internal testing environment of the accumulator. Therefore, this paper proposes an accumulator piston displacement signal compensation method based on rotational factors and support vector regression. Firstly, empirical mode decomposition is utilized to denoise the signal. Then, rotational factors are used to generate a delay compensation module to compensate for the signal attenuation and time delay caused by metallic reflection and scattering within the cylinder of the radar signal. The support vector regression model is improved based on a hash table to enhance its computation... [more]
Impact of TEMPO-Oxidation Pretreatment of Red Ginseng Residual on Nanofibrillation
Audrey Zahra, Virginia Ghita Firsty, Soo-Jeong Shin.
June 5, 2024 (v1)
Subject: Materials
Keywords: chemical oxidation, nanofibrillation, red ginseng residual, TEMPO-oxidation.
Red ginseng extract is one of the most widely used herbal medicines to prevent and cure various diseases. Among the processed products derived from red ginseng, the water-insoluble part as red ginseng residual (RGR) becomes waste, even though it contains important ingredients. TEMPO-oxidation (TO) can be used as a pre-treatment with different degrees of oxidation (DO) (0 to 0.4) in red ginseng residual (RGR-TO) by introducing chemical oxidation and high-pressure homogenizer (HPH) as a nanofibrillation process. 1H NMR was used to determine the carbohydrate composition and calculate DO, size was examined using a nanoparticle analyzer, and the zeta potential was used to determine surface charge density. RGR-TO with different concentrations had different compositions; glucose and uronic acid were the main ingredients. All treated RGR-TO showed higher oxidant levels than the untreated counterpart (RGR-TO 0). As the oxidant levels increased, the zeta potential and uronic acid increased, but... [more]
Oil and Gas Well Engineering Measurement and Control
Tianshou Ma, Yuqiang Xu.
June 5, 2024 (v1)
Oil and gas wells represent a unique channel in regard to oil and gas exploration and production [...]
Integration of Chemical Looping Combustion to a Gasified Stream with Low Hydrogen Content
Guadalupe S. Fraga-Cruz, Mario A. Pérez-Méndez, Gladys Jiménez-García, Rafael Huirache-Acuña, Fabricio Nápoles-Rivera, Jaime Espino-Valencia, Rafael Maya-Yescas.
June 5, 2024 (v1)
Keywords: Carbon Dioxide, chemical looping combustion, mass and energy balances, reduction of emissions, Syngas.
Global population growth requires the use of various natural resources to satisfy the basic needs of humanity. Fossil fuels are mainly used to produce electricity, transportation and the artificial air conditioning of habitats. Nevertheless, countries around the world are looking for alternative energy sources due to the decrease in the availability of these fuels and their high environmental impact. The mixture of hydrogen and carbon monoxide (H2 + CO), commonly called syngas, is a high-value feedstock for various industrial applications. By varying the composition of syngas, especially the H2/CO molar ratio, it can be used to produce methanol, fuels or synthetic natural gas. However, when this ratio is very low, the separation of this gas usually represents a great problem when making the energy balance, which is why it is proposed to adapt a combustion process in chemical cycles, taking advantage of the energy of this gas, reducing the energy impact of the process. During the presen... [more]
Adsorbent Biomaterials Based on Natural Clays and Orange Peel Waste for the Removal of Anionic Dyes from Water
Sonia Mihai, Andreea Bondarev, Cătalina Călin, Elena-Emilia Sȋrbu.
June 5, 2024 (v1)
Subject: Materials
Keywords: Adsorption, adsorption kinetics, dye removal, equilibrium isotherm, natural clay, orange peel, thermodynamics.
This study demonstrates the efficient removal of Alizarin Yellow R anionic dye (AY) from aqueous solutions using green adsorbents. Natural kaolin clay (A1), acid-modified natural clay (A2), chemically treated orange peel (C1) and biochar produced by the thermal treatment of orange peel (C2) were tested for the adsorption of AY. The characteristics of the sorbents were determined by instrumental methods: SEM, EDS, FTIR, BET and TGA. The adsorption experiments were performed under different conditions, including the initial AY dye concentration, adsorbent weight, pH, temperature and contact time. The maximum adsorption capacities had values between 15.72 and 74.62 mg/g at 298 K and the optimal pH of 6.5 at initial concentrations ranging from 30 to 70 mg/L for all adsorbents. The equilibrium data were used for the adsorption isotherm models: Freundlich, Langmuir and Temkin. The Freundlich model fit best for the adsorbents A2, C1 and C2, and the Langmuir isotherm had the highest regression... [more]
Response Surface Methodology: An Optimal Design for Maximising the Efficiency of Microwave-Assisted Extraction of Total Phenolic Compounds from Coriandrum sativum Leaves
Soraya Hihat, Noureddine Touati, Abdelhakim Sellal, Khodir Madani.
June 5, 2024 (v1)
Keywords: Coriandrum sativum, microwave-assisted extraction, response surface methodology, total antioxidant capacity, total phenolic compounds.
The optimization of total phenolic compounds (TPC) extraction yield and maximization of total antioxidant capacity (TAC) from coriander leaves were investigated using response surface methodology. The extraction of TPC was carried out using microwave-assisted extraction. A Box-Behnken design was used to study the effects of the three independent variables, solvent concentration (ethanol/water 20−80%), microwave power (100−500 watt) and irradiation time (30−150 s) on the response. A second-order polynomial model was used to predict the reaction. The regression analysis showed that about 99% of the variations could be explained by the models. The predicted values were 50.97 GAE/g dw and 5.75 mg GAE/g dw for TPC and TAC, respectively. The reaction surface analysis showed that the optimum extraction parameters that maximized the extraction of antioxidants yield were 52.62% ethanol, 452.12 watt and 150 s. Under optimal conditions, the experimental values for TPC and TAC were 49.63 ± 0.93 mg... [more]
Improving Polyp Segmentation with Boundary-Assisted Guidance and Cross-Scale Interaction Fusion Transformer Network
Lincen Jiang, Yan Hui, Yuan Fei, Yimu Ji, Tao Zeng.
June 5, 2024 (v1)
Keywords: boundary-assisted guidance, cross-scale interaction, polyp segmentation, transformer.
Efficient and precise colorectal polyp segmentation has significant implications for screening colorectal polyps. Although network variants derived from the Transformer network have high accuracy in segmenting colorectal polyps with complex shapes, they have two main shortcomings: (1) multi-level semantic information at the output of the encoder may result in information loss during the fusion process and (2) failure to adequately suppress background noise during segmentation. To address these challenges, we propose a cross-scale interaction fusion transformer for polyp segmentation (CIFFormer). Firstly, a novel feature supplement module (FSM) supplements the missing details and explores potential features to enhance the feature representations. Additionally, to mitigate the interference of background noise, we designed a cross-scale interactive fusion module (CIFM) that combines feature information between different layers to obtain more multi-scale and discriminative representative f... [more]
Improving Microalgae Feasibility Cultivation: Preliminary Results on Exhausted Medium Reuse Strategy
Luigi Marra, Elena Aurino, Francesca Raganati, Antonino Pollio, Antonio Marzocchella.
June 5, 2024 (v1)
Subject: Environment
Keywords: medium reuse, microalgae, substrate recovery, water footprint.
Although microalgae exploitation is very promising, process sustainability is undermined by biomass production and harvesting. Among the various bottlenecks of the production process, particular attention should be paid to the water footprint. Indeed, a huge volume of water is required in microalgae production. Water reuse can support both the water footprint and medium cost reduction, saving water and unconverted substrates. The present study reports preliminary results regarding the utilization of a water reuse strategy for two Chlorophyta microalgae under batch conditions. Growth parameters and chlorophyll content are monitored and the optimal amount of reused medium is assessed. The results show that 70% of the medium can be reused with no loss of specific growth rate and chlorophyll fraction for Pseudococcomyxa simplex in three consecutive batch cultivations. By contrast, a significant decline in Chlorella vulgaris growth was observed after the first cultivation in reused medium,... [more]
Predictive Modeling for Microchannel Flow Boiling Heat Transfer under the Dual Effect of Gravity and Surface Modification
Haoxian Wu, Shengnan Zhou, Dongwei Wang, Yunbo Yang, Linglin Liu, Huijie Mao, Bifen Shu.
June 5, 2024 (v1)
Keywords: dual effect, gravity, heat transfer model, micro devices, surface modification.
This paper investigates the heat transfer performance of flow boiling in microchannels under the dual effect of gravity and surface modification through both experimental studies and mechanistic analysis. Utilizing a test bench with microchannels featuring surfaces of varying wettability levels and adjustable flow directions, multiple experiments on R134-a flow boiling heat transfer under the effects of gravity and surface modification were conducted, resulting in 1220 sets of experimental data. The mass flux ranged from 735 kg/m2s to 1271 kg/m2s, and the heating heat flux density ranged from 9 × 103 W/m2 to 46 × 103 W/m2. The experimental results revealed the differences in the influence of different gravity and surface modification conditions on heat transfer performance. It was found that the heat transfer performance of super-hydrophilic surfaces in horizontal flow is optimal and more stable heat transfer performance is observed when gravity is aligned with the flow direction. And... [more]
The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale
Dengji Tang, Jianfa Wu, Jinzhou Zhao, Bo Zeng, Yi Song, Cheng Shen, Lan Ren, Yongzhi Huang, Zhenhua Wang.
June 5, 2024 (v1)
Keywords: effective fracture network volume (EFNV), flow back data, fracture network fracturing, Genetic Algorithm, shale gas.
Fracture network fracturing is pivotal for achieving the economical and efficient development of shale gas, with the connectivity among fracture networks playing a crucial role in reservoir stimulation effectiveness. However, flow back data that reflect fracture network connectivity information are often ignored, resulting in an inaccurate prediction of the effective fracture network volume (EFNV). The accurate calculation of the EFNV has become a key and difficult issue in the field of shale fracturing. For this reason, the accurate shale gas effective fracture network volume inversion method needs to be improved. Based on the flow back characteristics of fracturing fluids, a tree-shaped fractal fracture flow back mathematical model for inversion of EFNV was established and combined with fractal theory. A genetic algorithm workflow suitable for EFNV inversion of shale gas was constructed based on the flow back data after fracturing, and the fracture wells in southern Sichuan were used... [more]
Optimizing Microwave-Assisted Extraction from Levisticum officinale WDJ Koch Roots Using Pareto Optimal Solutions
Michał Plawgo, Sławomir Kocira, Andrea Bohata.
June 5, 2024 (v1)
Keywords: antioxidant activity, Extraction, lovage, Modelling, Pareto optimality, polyphenols.
The current research trend is not only focused on advanced techniques to intensify the extraction of bioactive compounds from plants, but also on the optimization process. The objective of this work was the implementation of the multiple criteria analysis using navigation on Pareto sets to determine the optimal parameters for the microwave-assisted extraction of Levisticum officinale WDJ Koch roots in order to obtain the maximum efficiency of the antioxidant potential of the extracts. The optimized parameters were extraction time, microwave power, and plant biomass/solvent ratio, while the evaluation criteria were based on the total phenols, flavonoids, reducing sugars, and antioxidant capacity. It was shown that the process parameters analyzed, i.e., biomass/solvent ratio, process time, and microwave power, determined the extraction efficiency of total phenolic content (TPC). A different observation was made for the analysis of total flavonoid content (TFC) and total antioxidant poten... [more]
Improving Ammonia Emission Model of Urea Fertilizer Fluidized Bed Granulation System Using Particle Swarm Optimization for Sustainable Fertilizer Manufacturing Practice
Norhidayah Mohamad, Nor Azlina Ab. Aziz, Anith Khairunnisa Ghazali, Mohd Rizal Salleh.
June 5, 2024 (v1)
Subject: Optimization
Keywords: ammonia emission, granulation, Particle Swarm Optimization, urea fertilizer.
Granulation is an important class of production processes in food, chemical and pharmaceutical manufacturing industries. In urea fertilizer manufacturing, fluidized beds are often used for the granulation system. However, the granulation processes release ammonia to the environment. Ammonia gas can contribute to eutrophication, which is an oversupply of nitrogen and acidification to the ecosystems. Eutrophication may cause major disruptions of aquatic ecosystems. It is estimated that global ammonia emissions from urea fertilizer processes are approximately at 10 to 12 Tg N/year, which represents 23% of overall ammonia released globally. Therefore, accurate modeling of the ammonia emission by the urea fertilizer fluidized bed granulation system is important. It allows for the system to be operated efficiently and within sustainable condition. This research attempts to optimize the model of the system using the particle swarm optimization (PSO) algorithm. The model takes pressure (Mpa),... [more]
The Storage Process of Electric Energy Produced from Renewable Sources from Hydrogen to Domestic Hot Water Heating
Dorel Stoica, Lucian Mihăescu, Gheorghe Lăzăroiu, George Cristian Lăzăroiu.
June 5, 2024 (v1)
Keywords: green hydrogen, power grids, renewable electricity, storage processes.
The expansion of renewable electricity storage technologies, including green hydrogen storage, is spurred by the need to address the high costs associated with hydrogen storage and the imperative to increase storage capacity. The initial section of the paper examines the intricacies of storing electricity generated from renewable sources, particularly during peak periods, through green hydrogen. Two primary challenges arise: firstly, the complexity inherent in the storage technology and its adaptation for electricity reproduction; and secondly, the cost implications throughout the technological chain, resulting in a significant increase in the price of the reproduced energy. Electric energy storage emerges as a pivotal solution to accommodate the growing proportion of renewable energy within contemporary energy systems, which were previously characterized by high stability. During the transition to renewable-based energy systems, optimizing energy storage technology to manage power flu... [more]
The Application of Rotary Twist Collecting Actuator Systems for Camellia oleifera Flower Bud Collection
Qing Zhao, Lijun Li, Zhifeng Yang.
June 5, 2024 (v1)
Subject: Environment
Keywords: Camellia oleifera, flower bud collecting, rotary twist, shear type, triple-finger linkage.
Pollen transmission of Camellia oleifera is affected by climate and environment, and the quality of natural pollination is not high, which seriously affects the yield of Camellia oleifera. Artificial pollination is an effective way to solve the low fruit setting rate of natural pollination, but the problem to be solved urgently in artificial pollination is the collection of a large amount of pollen. At present, there is no mechanized equipment for Camellia oleifera flower bud collection, so developing an efficient pollen collection device has become a key problem that restricts the high-quality development of Camellia oleifera. In this paper, on the basis of measuring the tensile force, the shearing force, and the torsional moment required to remove Camellia Oleifera flower bud from the branch, which are 8.968 N, 13.94 N, and 0.0178 N·m, respectively, three types of Camellia oleifera flower bud collecting actuators were designed. According to the results of parameter design, feasibilit... [more]
Combustion Characteristics, Kinetics and Thermodynamics of Peanut Shell for Its Bioenergy Valorization
Jialiu Lei, Xiaoyu Liu, Biao Xu, Zicong Liu, Yongjun Fu.
June 5, 2024 (v1)
Subject: Other
Keywords: combustion characteristics, isoconversional methods, kinetics and thermodynamics, peanut shell, thermogravimetric analysis.
To realize the utilization of peanut shell, this study investigates the combustion behavior, chemical kinetics and thermodynamic parameters of peanut shell using TGA under atmospheric air at the heating rates of 10, 20, and 30 K/min. Results indicate that increasing the heating rate leads to higher ignition, burnout, and peak temperatures, as observed in the TG/DTG curves shifting to the right. Analysis of combustion performance parameters suggest that higher heating rates can enhance combustion performances. Kinetic analysis using two model-free methods, KAS and FWO, shows that the activation energy (Eα) ranges from 93.30 to 109.65 kJ/mol for FWO and 89.72 to 103.88 kJ/mol for KAS. The data fit well with coefficient of determination values (R2) close to 1 and the mean squared error values (MSE) less than 0.006. Pre-exponential factors using FWO range from 2.19 × 106 to 8.08 × 107 s−1, and for KAS range from 9.72 × 105 to 2.25 × 107 s−1. Thermodynamic analysis indicates a low-energy ba... [more]
High-Performance Porous pSi/Ag@C Anode for Lithium-Ion Batteries
Kefan Li, Xiang Li, Liang Yuan, Zewen Han, Mengkui Li, Rui Ji, Yixin Zhan, Kai Tang.
June 5, 2024 (v1)
Keywords: anode, kerf loss silicon, pSi/Ag@C composite, silver particles.
Silicon represents one of the most attractive anode materials in lithium-ion batteries (LIBs) due to its highest theoretical specific capacity. Thus, there is a most urgent need to prepare Si-based nano materials in a very efficient way and develop some reasonable approaches for their modification in order to resolve the short-falls of Si anodes, which include both low conductivity and huge volume changes during intercalation of lithium ions. In this work, the kerf loss silicon (KL Si) from the photovoltaic industry has been used as an inexpensive Si source for the preparation of a porous silicon/silver/carbon composite (pSi/Ag@C) as an anode material. Porous silicon was embedded with Ag particles via the Ag-catalyzed chemical etching process, providing additional space to accommodate the large volume expansion of silicon. After carbon coating from polymerization of tannic acid on the surface of pSi/Ag, a high-speed conductive network over the surface of silicon was built and contribut... [more]
Comparative Study of the Stilbenes and Other Phenolic Compounds in Cabernet Sauvignon Wines Obtained from Two Different Vinifications: Traditional and Co-Inoculation
Aleksandar Petrović, Nikolina Živković, Ljilja Torović, Ana Bukarica, Vladan Nikolić, Jelena Cvejić, Ljiljana Gojković-Bukarica.
June 5, 2024 (v1)
Subject: Biosystems
Keywords: co-inoculation, non-Saccharomyces yeast, phenolic compounds, quercetin, Torulaspora delbrueckii, trans-resveratrol.
From grape cultivation to ripening and harvest timing to processing, each step of the winemaking process can be a critical point when it comes to wine quality and phenolic composition. In this study, the influence of winemaking technology on resveratrol and quercetin content, as well as other polyphenolic compounds, was investigated. Resveratrol is a non-flavonoid polyphenolic stilbene synthesized by grape skin when damaged by infectious diseases or ionizing radiation. Quercetin is a phenol found in grape skins and stems and is produced to protect grapes from UV light damage. Trans-resveratrol and quercetin are known to act as antioxidants, reduce the risk of atherosclerosis and type 2 diabetes, inhibit the growth of cancer cells, and prevent the release of allergic and inflammatory molecules. However, the question was whether red wine could be enriched with these phenols using a co-inoculation winemaking technology. The main new idea was to completely replace the cold maceration proce... [more]
Study on the Mechanism of Carbon Dioxide Miscible Fracturing Fluid Huff and Puff in Enhanced Oil Recovery
Shijing Xu, Changquan Wang, Bin Gao, Tiezheng Wang.
June 5, 2024 (v1)
Keywords: CO2 miscible fracturing fluid, enhanced oil recovery, huff and puff, low-permeability reservoir, minimum miscible pressure.
Carbon dioxide (CO2) miscible fracturing huff-and-puff technology now plays a pivotal role in enhancing crude oil recovery rates, particularly in reservoirs with challenging physical properties, strong water sensitivity, high injection pressure, and complex water-injection dynamics. In this study, the oil-increasing mechanism and huff-and-puff effect of CO2 miscible fracturing fluid are investigated through a comprehensive experimental approach. Specifically, experiments on PVT gas injection expansion, minimum miscible pressure, and CO2 miscible fracturing fluid huff and puff are conducted on the G fault block reservoir of the J Oilfield. The experimental findings demonstrate that injecting CO2 into reservoirs leads to an expansion in oil volume, a reduction in viscosity, and an increase in saturation pressure. Crude oil extraction is further enhanced by the addition of solubilizers and viscosity reducers. The use of solubilizers not only increases oil recovery rates but also reduces t... [more]
Fungal Isolation, Detection, and Quantification of Aflatoxins in Nuts Sold in the Lebanese Market
Heba Hellany, Jean Claude Assaf, Joseph Matta, Mahmoud I. Khalil.
June 5, 2024 (v1)
Subject: Biosystems
Keywords: aflatoxins, ELISA, HPLC, Lebanese nuts, toxigenic fungi.
This study examines the prevalence of aflatoxin contamination in 160 nut samples, both shelled and unshelled (including pistachios, peanuts, and walnuts), from the Lebanese market, focusing on their fungal contamination and specific toxigenic strains. Aflatoxin B1 (AFB1), known for its potent carcinogenic and immunosuppressive properties, was detected in various samples. Moisture content analysis showed that unshelled nuts often exceeded maximum moisture limits more frequently than shelled nuts, with levels ranging from 1.9 to 9.5%. The predominant fungal genus identified through cultivation on potato dextrose agar (PDA) plates was Aspergillus. In total, 55% of samples were contaminated with A. flavus and 45% with A. niger. All toxigenic strains isolated were identified as Aspergillus flavus. The aflatoxins, particularly AFB1, were quantified using the enzyme-linked immunosorbent assay (ELISA) and reversed-phase high-performance liquid chromatography (HPLC), revealing contamination in... [more]
Development of New Series of Certified Reference Materials for Ferrosilicon Magnesium Alloys
Justyna Kostrzewa, Jacek Anyszkiewicz, Tadeusz Gorewoda, Ewa Jamroz, Kjell Blandhol, Alf Yngve Guldhav, Magdalena Knapik, Jadwiga Charasińska, Agata Jakóbik-Kolon.
June 5, 2024 (v1)
Subject: Materials
Keywords: certified reference materials, silicon alloys, traceability.
This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were d... [more]
Thermal Stress Mechanism of Thermochemical Reactor of 5 kW Solar Simulator with Temperature Distribution as the Load Condition
Xing Huang, Yan Lin, Xin Yao, Yang Liu, Fanglin Gao, Hao Zhang.
June 5, 2024 (v1)
Subject: Materials
Keywords: safety, solar thermochemical reactor, temperature field, thermal stress.
In this paper, a solar thermochemical reactor is designed based on a 5 kW non-coaxial concentrating solar simulator, and a mathematical model is established for thermal calculations. The calculated temperature distribution is used as a load condition for thermal stress analyses. The model is used to study the influence of the solar simulator power, solar reactor inner wall material’s emissivity, working pressure, gas inlet velocity, and thermocouple opening diameter on the thermal stress of the solar reactor. The results show that thermal stress increases with the increase in solar simulator power and the emissivity of the inner wall material in the solar reactor. The inlet velocity and working pressure have little effect on the thermal stress of the reactor and cannot prevent damage to the reactor. In the case of maintaining the diameter of the thermocouple at the front end of the reactor, increasing the diameter of the thermocouple inside the reactor leads to an increase in thermal s... [more]
Plateau-Adapted Single-Pump, Single-Bed Vacuum Pressure Swing Adsorption Oxygen Generation Process Simulation and Optimization
Yingying Zhang, Yanbin Li, Zhenxing Song, Hongyun Sun, Bolun Wen, Junming Su, Jun Ma, Yanjun Zhang.
June 5, 2024 (v1)
Keywords: numerical simulation, plateau oxygen generation, vacuum pressure swing adsorption.
To enhance the oxygen guarantee capacity in high altitude areas and address the challenges of traditional pressure swing adsorption oxygen generation fixed equipment with large volume and multiple device modules, a novel single-reversible-pump single-bed vacuum pressure swing adsorption (VPSA) oxygen generation process was proposed and simulated. This study investigated the effects of purge on oxygen productivity, purity, recovery, and energy consumption, determining that the optimum ratio of total oxygen in the purge gas to the total oxygen in the feed gas (P/F) was 0.176. A set of principle prototypes was developed and validated in plains. The process performance was then simulated and studied at altitudes of 3000 m, 4000 m, and 5000 m. Finally, the optimization was carried out by adjusting the product flow rate and feed flow rate, revealing that the best performance can be achieved when the oxygen purity exceeded 90% with lower energy consumption or larger productivity than the opti... [more]
Performance Improvement of an Electric Vehicle Charging Station Using Brain Emotional Learning-Based Intelligent Control
Sherif A. Zaid, Hani Albalawi, Aadel M. Alatwi, Atef Elemary.
June 5, 2024 (v1)
Keywords: brain emotional learning intelligent control, charging station, electric vehicle, PV.
Electric vehicle (EV) charging facilities are essential to their development and deployment. These days, autonomous microgrids that use renewable energy resources to energize charging stations for electric vehicles alleviate pressure on the public electricity grid. Nevertheless, controlling and managing such charging stations’ energy is difficult due to the nonlinearity and irregular character of renewable energy sources. The current research recommends using a Brain Emotional Learning Intelligent Control (BELBIC) controller to enhance an autonomous EV charging station’s performance and power management. The charging station uses a battery to store energy and is primarily powered by photovoltaic (PV) solar energy. The principles of BELBIC are dependent on emotional cues and sensory inputs, and they are based on an emotion processing system in the brain. Noise and parameter variations do not affect this kind of controller. In this study, the performance of a conventional proportional−in... [more]
Propagation Mechanism and Suppression Strategy of DC Faults in AC/DC Hybrid Microgrid
Chun Xiao, Yulu Ren, Qiong Cao, Ruifen Cheng, Lei Wang.
June 5, 2024 (v1)
Keywords: AC/DC hybrid microgrid, bidirectional power converter, current limiting strategy, fault propagation, mechanism analysis.
Due to their efficient renewable energy consumption performance, AC/DC hybrid microgrids have become an important development form for future power grids. However, the fault response will be more complex due to the interconnected structure of AC/DC hybrid microgrids, which may have a serious influence on the safe operation of the system. Based on an AC/DC hybrid microgrid with an integrated bidirectional power converter, research on the interaction impact of faults was carried out with the purpose of enhancing the safe operation capability of the microgrid. The typical fault types of the DC sub-grid were selected to analyze the transient processes of fault circuits. Then, AC current expressions under the consideration of system interconnection structure were derived and, on this basis, we obtained the response results of non-fault subnets under the fault process, in order to reveal the mechanism of DC fault propagation. Subsequently, a current limitation control strategy based on virtu... [more]
Solid−Liquid Two-Phase Flowmeter Flow-Passage Wall Erosion Evolution Characteristics and Calibration of Measurement Accuracy
Wei Han, Lumin Yan, Rennian Li, Jing Zhang, Xiang Yang, Lei Ji, Yan Qiang.
June 5, 2024 (v1)
Subject: Environment
Keywords: erosion characteristics, measurement accuracy, particle dynamics parameters.
Solid−liquid two-phase flowmeters are widely used in critical sectors, such as petrochemicals, energy, manufacturing, the environment, and various other fields. They are indispensable devices for measuring flow. Currently, research has primarily focused on gas−liquid two-phase flow within the flowmeter, giving limited attention to the impact of solid phases. In practical applications, crude oil frequently contains solid particles and other impurities, leading to equipment deformation and a subsequent reduction in measuring accuracy. This paper investigates how particle dynamic parameters affect the erosion evolution characteristics of flowmeters operating in solid−liquid two-phase conditions, employing the dynamic boundary erosion prediction method. The results indicate that the erosion range and peak erosion position on the overcurrent wall of the solid−liquid two-phase flowmeter vary with different particle dynamic parameters. Erosion mainly occurs at the contraction section of the s... [more]
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