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Showing records 1261 to 1285 of 43292. [First] Page: 1 48 49 50 51 52 53 54 55 56 Last
Numerical Simulation Study of Energy Separation in Jet Shear Layer
Wanwen Xu, Ruoling Dong, Shuang Liang.
June 7, 2024 (v1)
Keywords: dual jet, energy separation, mechanism, numerical simulation, velocity.
In order to investigate the rational utilization of energy in the fluid jet process, a free dual jet of parallel air is used as a research object. Simulation of turbulence was carried out based on the realizable k-epsilon equations with pressure-velocity coupling, PISO method, discrete method with second-order windward format, and first-order implicit transient solution. The energy separation phenomenon within the jet shear layer and its influencing factors were investigated under dual-jet Reynolds number differences of 12,800, 19,200, 25,600, 32,000, 41,500, and 51,100, respectively. The simulation is in transient format and the jet inlet velocity is given by udf. Calculations show that the pressure perturbation in the air shear layer, which gives rise to the pressure work exchange between the jet and the surroundings, is the main reason for the coexistence of high- and low-temperature regions formed within the jet shear layer, and the larger the Reynolds number, the stronger the ener... [more]
CrossTx: Cross-Cell-Line Transcriptomic Signature Predictions
Panagiotis Chrysinas, Changyou Chen, Rudiyanto Gunawan.
June 7, 2024 (v1)
Keywords: autoencoder, drug repurposing, drug signature, gene expression, principal component analysis.
Predicting the cell response to drugs is central to drug discovery, drug repurposing, and personalized medicine. To this end, large datasets of drug signatures have been curated, most notably the Connectivity Map (CMap). A multitude of in silico approaches have also been formulated, but strategies for predicting drug signatures in unseen cells—cell lines not in the reference datasets—are still lacking. In this work, we developed a simple-yet-efficacious computational strategy, called CrossTx, for predicting the drug transcriptomic signatures of an unseen target cell line using drug transcriptome data of reference cell lines and unlabeled transcriptome data of the target cells. Our strategy involves the combination of Predictor and Corrector steps. The Predictor generates cell-line-agnostic drug signatures using the reference dataset, while the Corrector produces target-cell-specific drug signatures by projecting the signatures from the Predictor onto the transcriptomic latent space of... [more]
Effect of Displacement Pressure Gradient on Oil−Water Relative Permeability: Experiment, Correction Method, and Numerical Simulation
Jintao Wu, Lei Zhang, Yingxian Liu, Kuiqian Ma, Xianbo Luo.
June 7, 2024 (v1)
Keywords: correction, displacement pressure gradient, experiment, numerical simulation, relative permeability.
Relative permeability is a fundamental parameter affecting reservoir development performance analysis. During the development of oil and gas fields, the displacement pressure gradient changes with time and space. This paper studies the effect of displacement pressure gradient on relative permeability. The oil−water relative permeability curves of a Bohai Oilfield under different displacement pressure gradients are obtained through experimental analysis. Based on the experimental data, a correction model of the permeability curve is established by regression of the Willhite model parameters. The correction model is introduced into the black oil numerical simulation, and the production performance and remaining oil are compared and analyzed. The results show that the displacement pressure gradient can have an obvious impact on the relative permeability curve. As the displacement pressure gradient increases, the two-phase span of the relative permeability curve increases, the oil displace... [more]
Enhancing Control Room Operator Decision Making
Joseph Mietkiewicz, Ammar N. Abbas, Chidera W. Amazu, Gabriele Baldissone, Anders L. Madsen, Micaela Demichela, Maria Chiara Leva.
June 7, 2024 (v1)
Keywords: Artificial Intelligence, control room operators, decision support systems, dynamic influence diagrams, process control, reinforcement learning, situation awareness, task overload, trust in automation.
In the dynamic and complex environment of industrial control rooms, operators are often inundated with numerous tasks and alerts, leading to a state known as task overload. This condition can result in decision fatigue and increased reliance on cognitive biases, which may compromise the decision-making process. To mitigate these risks, the implementation of decision support systems (DSSs) is essential. These systems are designed to aid operators in making swift, well-informed decisions, especially when their judgment may be faltering. Our research presents an artificial intelligence (AI)-based framework utilizing dynamic influence diagrams and reinforcement learning to develop a powerful decision support system. The foundation of this AI framework is the creation of a robust, interpretable, and effective DSS that aids control room operators during critical process disturbances. By incorporating expert knowledge, the dynamic influence diagram provides a comprehensive model that captures... [more]
Precise Lightning Strike Detection in Overhead Lines Using KL-VMD and PE-SGMD Innovations
Xinsheng Dong, Jucheng Liu, Shan He, Lu Han, Zhongkai Dong, Minbo Cai.
June 7, 2024 (v1)
Keywords: KL-VMD, lightning strike, PE-SGMD, traveling wave, zero-mode voltage.
When overhead lines are impacted by lightning, the traveling wave of the fault contains a wealth of fault information. The accurate extraction of feature quantities from transient components and their classification are fundamental to the identification of lightning faults. The extraction process may involve modal aliasing, optimal wavelet base issues, and inconsistencies between the lightning strike distance and the fault point. These factors have the potential to impact the effectiveness of recognition. This paper presents a method for identifying lightning strike faults by utilizing Kullback−Leibler (KL) divergence enhanced Variational Mode Decomposition (VMD) and Symmetric Geometry Mode Decomposition (SGMD) improved with Permutation Entropy (PE) to address the aforementioned issues. A model of a 220 kV overhead line is constructed using real faults to replicate scenarios of winding strike, counterstrike, and short circuit. The three-phase voltage is chosen and then subjected to Kar... [more]
Detection of Multiplicative False Data Injection Cyberattacks on Process Control Systems via Randomized Control Mode Switching
Shilpa Narasimhan, Matthew J. Ellis, Nael H. El-Farra.
June 7, 2024 (v1)
Keywords: cyberattack detection, multiplicative false data injection attacks, randomized control mode switching.
A fundamental problem at the intersection of process control and operations is the design of detection schemes monitoring a process for cyberattacks using operational data. Multiplicative false data injection (FDI) attacks modify operational data with a multiplicative factor and could be designed to be detection evading without in-depth process knowledge. In a prior work, we presented a control mode switching strategy that enhances the detection of multiplicative FDI attacks in processes operating at steady state (when process states evolve within a small neighborhood of the steady state). Control mode switching on the attack-free process at steady-state may induce transients and generate false alarms in the detection scheme. To minimize false alarms, we subsequently developed a control mode switch-scheduling condition for processes with an invertible output matrix. In the current work, we utilize a reachable set-based detection scheme and use randomized control mode switches to augmen... [more]
Catalytic Acetone Oxidation over MnOx Catalysts: Regulating Their Crystal Structures and Surface Properties
Bohang Cai, Fawei Lin, Xuan Guo, Yongtao Li.
June 7, 2024 (v1)
Keywords: calcination conditions, microwave hydrothermal, MnOx catalysts, VOC oxidation.
This study investigates the catalytic oxidation of acetone by different crystal phases of MnO2 prepared via different methods. Compared with β-MnO2 and γ-MnO2, α-MnO2 exhibited superior catalytic activity. Moreover, as replacements for traditional hydrothermal methods and air calcination, the use of microwave hydrothermal methods and N2 calcination significantly enhanced the catalytic performance of the MnO2 catalyst. The optimal catalyst, MnO2-WN (α-MnO2 synthesized via microwave hydrothermal method and N2 calcination), converted 100% of 100 ppm acetone below 150 °C, with the CO2 yields reaching 100%. Further, the stability of the catalyst and its potential for other volatile organic compounds (VOCs) were also determined. The experimental data demonstrated that its outstanding activity primarily stemmed from the improved preparation method, enhancing the specific surface area of the catalyst, optimizing the pore structure, improving the redox performance, and generating more acidic si... [more]
A Two-Stage Stochastic Programming Approach for the Design of Renewable Ammonia Supply Chain Networks
Ilias Mitrai, Matthew J. Palys, Prodromos Daoutidis.
June 7, 2024 (v1)
Keywords: capacity expansion, green ammonia, Stochastic Optimization, supply chain optimization.
This work considers the incorporation of renewable ammonia manufacturing sites into existing ammonia supply chain networks while accounting for ammonia price uncertainty from existing producers. We propose a two-stage stochastic programming approach to determine the optimal investment decisions such that the ammonia demand is satisfied and the net present cost is minimized. We apply the proposed approach to a case study considering deploying in-state renewable ammonia manufacturing in Minnesota’s supply chain network. We find that accounting for price uncertainty leads to supply chains with more ammonia demand met via renewable production and thus lower costs from importing ammonia from existing producers. These results show that the in-state renewable production of ammonia can act as a hedge against the volatility of the conventional ammonia market.
The Splitter Blade Pump−Turbine in Pump Mode: The Hump Characteristic and Hysteresis Effect Flow Mechanism
Guanghe Dong, Zhumei Luo, Tao Guo, Xiaoxu Zhang, Rong Shan, Linsheng Dai.
June 7, 2024 (v1)
Keywords: entropy theory, hysteresis characteristic, internal flow characteristics, numerical simulation, plitter blade, pump–turbine.
This study focuses on the splitter blade pump−turbine as the research object to analyze the problems of hump characteristics and the hysteresis effect. We simulated the operation of the pump condition with small opening of the guide vane, analyzed the hydraulic loss by using the entropy production theory and entropy wall function, and investigated the study of internal flow transfer characteristics. In this paper, it was first verified that the maximum error of the energy loss calculated by the pressure method and the entropy production method was less than 6% for the working zone. From the quantified energy loss results, a significant instability feature was observed in the 0.65 QBEP−0.9 QBEP operating interval, accompanied by the phenomenon of the non-overlapping of the characteristic curves. The results show that the hump characteristic with hysteresis effect also exists in the splitter blade pump−turbine. The percentage of energy loss in the hump zone is in descending order of runn... [more]
Preparation of Nickel-Based Bimetallic Catalyst and Its Activation of Persulfate for Degradation of Methyl Orange
Bo Zhang, Jiale Li, Zhizhi Xu, Xiaohong Xu, Chundu Wu.
June 7, 2024 (v1)
Subject: Materials
Keywords: advanced oxidation, catalyst, methyl orange, persulfate.
In this research, a new catalyst for activating persulfate was developed by loading iron and nickel ions onto powdered activated carbon (PAC) for treating methyl orange, and the preparation process was optimized and characterized. The efficacy of the treatment was evaluated using the Chemical Oxygen Demand (COD) removal rate, which reflects the impact of various process parameters, including catalyst dosage, sodium persulfate dosage, and reaction pH. Finally, the recovery and reuse performance of the catalyst were studied. The optimal conditions for preparing the activated sodium persulfate catalyst were determined to be as follows: a molar ratio of Fe3+ and Fe2+ to Ni of 4:1, a mass ratio of Fe3O4 to PAC of 1:4, a calcination temperature of 700 °C, and a calcination time of 4 h. This preparation led to an increase in surface porosity and the formation of a hollow structure within the catalyst. The active material on the surface was identified as nickel ferrite, comprising the elements... [more]
Optimal Mesh Pore Size Combined with Periodic Air Mass Load (AML) for Effective Operation of a Self-Forming Dynamic Membrane BioReactor (SFD MBR) for Sustainable Treatment of Municipal Wastewater
Senouci Boulerial, Carlo Salerno, Fabiano Castrogiovanni, Marina Tumolo, Giovanni Berardi, Abdelkader Debab, Boumediene Haddou, Abdellah Benhamou, Alfieri Pollice.
June 7, 2024 (v1)
Keywords: air mass load, biological membrane, dynamic membrane, SFD MBR, trans-membrane pressure, turbidity.
A self-forming dynamic membrane bioreactor (SFD MBR) is a cost-effective alternative to conventional MBR, in which the synthetic membrane is replaced by a “cake layer,” an accumulation of the biological suspension over a surface of inert, low-cost support originated by filtration itself. Under optimized conditions, the cake layer is easy to remove and quick to form again, resulting a “dynamic membrane.” The permeate of the SFD MBR has chemo-physical characteristics comparable to those of conventional ultrafiltration-based MBR. In this paper, two nylon meshes with pore sizes of 20 and 50 µm, respectively, were tested in a bench-scale SFD MBR in which an air mass load (AML) was periodically supplied tangentially to the filtration surface to maintain filtration effectiveness. The SFD MBR equipped with 20 µm nylon mesh coupled with 5 min of AML every 4 h showed the best performance, ensuring both a permeate with turbidity values always below 3 NTU and revealing no increases in transmembran... [more]
Analysis and Optimization of the Fuel Consumption of an Internal Combustion Vehicle by Minimizing the Parasitic Power in the Cooling System
Pedro H. A. Brayner, José Â. P. da Costa, Alvaro A. V. Ochoa, José J. Urbano, Gustavo N. P. Leite, Paula S. A. Michima.
June 7, 2024 (v1)
Subject: Optimization
Keywords: cooling system, Energy Efficiency, fuel consumption, parasitic power.
This study aims to enhance energy efficiency by reducing parasitic losses in the engine cooling system through a new drive strategy involving a two-stage water pump and a variable electro-fan. The fuel consumption gain analysis focused on a vehicle with average characteristics typical of 1.0L hatchbacks in the Brazilian market and urban driving conditions. The methodology implemented aims to minimize power absorbed by the forced water circulation and thermal rejection, thereby reducing parasitic losses, particularly during low-speed urban driving, without causing air-side heat exchanger saturation. The results show a potential decrease of up to 80% in power absorbed by the cooling system, leading to an estimated fuel consumption saving of approximately 1.4% during urban driving cycles.
Analysis of Rock Burst Mechanism in Extra-Thick Coal Seam Controlled by Thrust Fault under Mining Disturbance
Suihan Yang, Xiangzhi Wei, Linlin Chen, Zhiliu Wang, Wen Wang.
June 7, 2024 (v1)
Keywords: extra-thick coal seam, mining disturbance, rock burst mechanism, strata behaviors, thrust fault.
A fault is a common geological structure encountered in underground coal mining. Interactions between the discontinuous structure of a fault and mining activities are the key factors in controlling the rock bursts induced by the fault. It is of great importance to study the rock burst mechanism of an extra-thick coal seam under the combined influence of reverse faults and coal mining for the prediction and prevention of rock burst. In this study, we establish a sliding dynamics model of rock mass in a fault zone and analyze the mechanical distribution of fault-induced rock bursts under the combined action of mining disturbances. Additionally, we utilize theoretical calculation and a 3D numerical simulation method to clarify the rockburst mechanism in an extra-thick coal seam controlled by a thrust fault under mining disturbance and a fault. The results showed that the distribution range of the shear stress increment in the fault footwall was larger than that in the hanging wall, reveal... [more]
Microbial Electrolysis Cell Exergy Evaluation
Valentin Nenov, Lyubka Atanasova, Hyusein Yemendzhiev, Ralitza Koleva.
June 7, 2024 (v1)
Keywords: exergy balance, Hydrogen, microbial electrolysis cell.
Bio-electrochemical systems have increasingly become the focus of research due to their potential in environmental biotechnology, particularly in the domains of waste utilization and energy recovery. A prominent method within this domain is the transformation of organic matter into hydrogen via microbial electrolysis cells (MECs). This study offers a thorough analysis of MEC performance, employing exergy analysis and incorporating relevant data from the existing literature. The findings of this research indicate a relationship between process efficiency and effective electron transfer originating from biological oxidation to the cathode reaction, facilitating hydrogen generation. The assessment performed revealed that the exergy efficiency of the process varies by a wide range, depending on conditions such as substrate type and concentration, applied external voltage, and the presence of specific inhibitors. This interplay between substrate concentration, overall efficiency, and energy... [more]
Optimizing the Thickness of Multilayer Thermal Insulation on Different Pipelines for Minimizing Overall Cost-Associated Heat Loss
Mohammed R. A. Alrasheed.
June 7, 2024 (v1)
Subject: Environment
Keywords: energy savings, life cycle cost analysis, multi-objective genetic algorithm, multilayer insulation, Optimization, thermal insulation.
Optimizing the multilayer thermal insulation of pipelines transporting liquids and gases at higher than ambient temperatures is crucial for heat energy conservation and cost optimization. This study utilizes a multi-objective genetic algorithm to optimize the multilayer thermal insulation thickness around a pipe carrying fluid to minimize heat loss and associated costs. The model adopted mathematical associations between design variables and the overall installation cost of layers over a pipe from the available literature. The proposed model considered one or more insulation layers of rock wool and calcium silicate to oil pipelines containing steam, furfural, reduced crude or 300-distillate oil. All calculations considered fixed-charge rates as a fraction of 1 or 0.15. The results were compared with standard values and those predicted by other researchers in the literature. For the steam line, the standard insulation thickness was 50 mm, jumping to 327 mm for rock wool and 232 mm for c... [more]
Optimizing the Extraction Process of Value-Added Products from Olive Cake Using Neuro-Fuzzy Models
Emilio J. Lozano, Gabriel Blázquez, Mónica Calero, María Ángeles Martín-Lara, Salvador Pérez-Huertas, Antonio Pérez.
June 7, 2024 (v1)
Subject: Environment
Keywords: Extraction, inositol, neuro-fuzzy models, olive cake, polyphenols, sugars.
The use of olive cake, an abundant residue in the olive oil industry, has been studied by developing a biorefinery scheme. The aim was to develop a novel, efficient, and environmentally friendly strategy for the valorization of olive cake, contributing to sustainable agriculture. A special extraction procedure based on a combination of hydrothermal treatments with liquid/liquid extractions was designed to produce value-added products, along with solids that can be used for energy or adsorbent production. The optimal extraction conditions were determined by exploring the influence of the operating variables (temperature, extraction time, solvent type, solvent/extract ratio, extraction stages, and pH) on the extraction yield. The decision about the optimal conditions was made by adjusting the experimental results to a neuro-fuzzy model. Glucose and inositol showed similar response surfaces, allowing simultaneous concentration in a single process. Under optimal extraction conditions, the... [more]
Review of the Potential of Probiotics in Disease Treatment: Mechanisms, Engineering, and Applications
Mingkang Liu, Jinjin Chen, Ida Putu Wiweka Dharmasiddhi, Shiyi Chen, Yilan Liu, Hongmei Liu.
June 7, 2024 (v1)
Keywords: action mechanisms, engineering strategies, living therapeutics, probiotics.
Probiotics, living microorganisms with demonstrated health benefits when administered in sufficient quantities, have a rich history as dietary supplements to benefit human health. Recently, understanding of their mechanisms in the gastrointestinal tract has prompted exploration of probiotics in treating human diseases. However, the effective and precise delivery of probiotics remains a significant challenge in therapeutic applications. Here, we review the mechanisms of action of probiotics in human health and the most advanced strategies for efficient probiotic delivery. We also discuss the potential applications of engineered probiotics in disease treatment. This review contributes insights into the evolving landscape of probiotic research for therapeutic applications.
Current Status and Economic Analysis of Green Hydrogen Energy Industry Chain
Xinrong Yan, Wenguang Zheng, Yajuan Wei, Zhaoqian Yan.
June 7, 2024 (v1)
Subject: Energy Policy
Keywords: application, economic analysis, Hydrogen, production, storage and transportation.
Under the background of the power system profoundly reforming, hydrogen energy from renewable energy, as an important carrier for constructing a clean, low-carbon, safe and efficient energy system, is a necessary way to realize the objectives of carbon peaking and carbon neutrality. As a strategic energy source, hydrogen plays a significant role in accelerating the clean energy transition and promoting renewable energy. However, the cost and technology are the two main constraints to green hydrogen energy development. Herein, the technological development status and economy of the whole industrial chain for green hydrogen energy “production-storage-transportation-use” are discussed and reviewed. After analysis, the electricity price and equipment cost are key factors to limiting the development of alkaline and proton exchange membrane hydrogen production technology; the quantity, scale and distance of transportation are key to controlling the costs of hydrogen storage and transportatio... [more]
Locality-Based Action-Poisoning Attack against the Continuous Control of an Autonomous Driving Model
Yoonsoo An, Wonseok Yang, Daeseon Choi.
June 7, 2024 (v1)
Keywords: adversarial attack, AI security, multi-agent reinforcement learning, poisoning attack, reinforcement learinng.
Various studies have been conducted on Multi-Agent Reinforcement Learning (MARL) to control multiple agents to drive effectively and safely in a simulation, demonstrating the applicability of MARL in autonomous driving. However, several studies have indicated that MARL is vulnerable to poisoning attacks. This study proposes a ’locality-based action-poisoning attack’ against MARL-based continuous control systems. Each bird in a flock interacts with its neighbors to generate the collective behavior, which is implemented through rules in the Reynolds’ flocking algorithm, where each individual maintains an appropriate distance from its neighbors and moves in a similar direction. We use this concept to propose an action-poisoning attack, based on the hypothesis that if an agent is performing significantly different behaviors from neighboring agents, it can disturb the driving stability of the entirety of the agents. We demonstrate that when a MARL-based continuous control system is trained... [more]
A Hybrid Feature-Selection Method Based on mRMR and Binary Differential Evolution for Gene Selection
Kun Yu, Wei Li, Weidong Xie, Linjie Wang.
June 7, 2024 (v1)
Subject: Optimization
Keywords: biomarker, differential evolution, feature selection, microarray data.
The selection of critical features from microarray data as biomarkers holds significant importance in disease diagnosis and drug development. It is essential to reduce the number of biomarkers while maintaining their performance to effectively minimize subsequent validation costs. However, the processing of microarray data often encounters the challenge of the “curse of dimensionality”. Existing feature-selection methods face difficulties in effectively reducing feature dimensionality while ensuring classification accuracy, algorithm efficiency, and optimal search space exploration. This paper proposes a hybrid feature-selection algorithm based on an enhanced version of the Max Relevance and Min Redundancy (mRMR) method, coupled with differential evolution. The proposed method improves the quantization functions of mRMR to accommodate the continuous nature of microarray data attributes, utilizing them as the initial step in feature selection. Subsequently, an enhanced differential evol... [more]
Exergy and Environmental Analysis for Optimal Condition Finding of a New Combined Cycle
Ibrahim B. Mansir.
June 7, 2024 (v1)
Subject: Environment
Keywords: energy recovery, exergo-economic, intercooled gas turbine, Kalina cycle, Optimization.
In this paper, various thermal energy systems are studied to recover waste heat from gas turbines with different configurations. The exergy analysis and environmental examination are applied to achieve better insight into the suggested systems. Also, multi-objective optimization is employed to find the optimal condition of the introduced plants. In this work, various systems such as gas turbine (GT), organic Rankine cycle (ORC), and Kalina cycle (KC) with Proton Exchange Membrane (PEM) electrolyzer are combined to achieve a new system design. In this study, Engineering Equation Solver (V11.755) and Matlab (R2023a) software are used to simulate and optimize the proposed system. The comparison of systems shows that the combustion chamber with 3622 kW has the most considerable exergy destruction in the IGT/ORC-KC plant. The comparative investigation shows that IGT/ORC-KC has the highest output at 5659 kW, while the smallest exergy destruction is associated with the IGT system with 1779 kW... [more]
Migration and Transformation of Heavy Metal and Its Fate in Intertidal Sediments: A Review
Nan Geng, Yinfeng Xia, Dongfeng Li, Fuqing Bai, Cundong Xu.
June 7, 2024 (v1)
Subject: Materials
Keywords: bioaccumulation, heavy metal, intertidal sediment, migration, transformation.
Intertidal sediments are rich in biological resources, which are important for material circulation and energy exchange. Meanwhile, these areas can be treated as sinks as well as sources of coastal heavy metal pollutants. Due to the influence of the tide, the intertidal sediments are in a state of periodic flooding and exposure, and environmental factors such as dissolved oxygen, salinity and overlying water pressure are changeable. Heavy metals in sediments are prone to migration and transformation with the dynamic effects of tidal water and the changes in the environment factors, which increase the bioavailability of heavy metals. In this review, the characteristics of distribution and the bioavailability of heavy metals in intertidal sediments are described; the migration and transformation behavior of heavy metals and its influencing factors under tidal conditions are analyzed; and the mechanisms of heavy metal’s migration and transformation in the intertidal zone are summarized. M... [more]
Research on Water Invasion Law and Control Measures for Ultradeep, Fractured, and Low-Porosity Sandstone Gas Reservoirs: A Case Study of Kelasu Gas Reservoirs in Tarim Basin
Dong Chen, Chengze Zhang, Min Yang, Haiming Li, Cuili Wang, Pengxiang Diwu, Hanqiao Jiang, Yong Wang.
June 7, 2024 (v1)
Keywords: embedded discrete fracture numerical simulation, fractured, low-porosity gas reservoirs, gas production rate, Kuqa Depression, large physical simulation.
The exploitation of ultradeep, fractured, and low-porosity gas reservoirs often encounters challenges from water invasion, exacerbated by the presence of faults and fractures. This is particularly evident in the Kelasu gas reservoir group, located in the Kuqa Depression of the Tarim Basin. The complexity of the water invasion patterns in these reservoirs demands a thorough investigation to devise effective water control measures. To elucidate the water invasion patterns, a combined approach of large-scale physical modeling and discrete fracture numerical simulations was adopted. These models allowed for the identification and categorization of water invasion behaviors in various gas reservoirs. Furthermore, production dynamic analysis was utilized to tailor water control strategies to specific invasion patterns. The large-scale physical simulation experiment revealed that water invasion in gas reservoirs is primarily influenced by high-permeability channels (faults + fractures), and th... [more]
A Numerical Simulation of the Coal Dust Migration Law in Directional Air Drilling in a Broken Soft Coal Seam
Jie Zhang, Zichen Han, Tianzhu Chen, Ningping Yao, Xianyu Yang, Chan Chen, Jihua Cai.
June 7, 2024 (v1)
Keywords: air volume, broken soft coal seam, coal dust migration, deposition degree, directional air drilling, numerical simulation.
Abundant industrial experiences have shown that directional air drilling technology is effective for gas drainage when drilling broken and soft coal seams. In this paper, the Eulerian−Eulerian model was used to simulate the gas−solid two-phase flow behavior of compressed air transporting coal dust in broken soft coal seams. The relationship between the degree of coal dust deposition, annular air pressure law, transportation of coal dust, aforementioned factors of rotational speed, particle size, and air volume could be determined. The results indicate that the particle size plays a significant role in the transport capacity of coal dust. Smaller particle sizes and a higher airflow result in a lower deposition degree of coal dust. When the particle size of coal dust is 1.69 mm and the airflow is 300 m3/h, in the case of coal dust generation at a rate of 0.24 m3/h, the deflection angle of the coal dust collection zone is increased by 130% as the rotational speed of the drill rod is incre... [more]
Eccentricity Analysis of the Co-Excitation Axial Reluctance Resolver during Manufacture and Installation
Hao Wang, Jundi Wang, Zongsheng Zhang, Changchao Li.
June 7, 2024 (v1)
Keywords: axial reluctance resolver, co-excitation, eccentricity, finite element simulation.
In this paper, a type of co-excitation axial reluctance resolver (CARR) in different winding modes is taken as the simulation model. Detailed explanations have been provided on its stator, rotor, and windings. Simultaneously, an introduction was made to the distribution of two types of signal winding modes. The influence of three kinds of eccentricity on the output characteristics of this CARR during installation and fabrication is also studied. According to two kinds of signal winding modes, the variation law of waveform and amplitude of output potential is analyzed under the conditions of stator radial eccentric distance in different eccentric directions, rotor radial eccentric distance in different eccentric directions and rotor axial offset, and the influence of three factors on total harmonic distortion (THD) is analyzed further. Under the conditions of different eccentricities and offset, a prototype of 15 pair pole CARRs in the mode of sinusoidal windings is tested. The function... [more]
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