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Showing records 51 to 75 of 1591. [First] Page: 1 2 3 4 5 6 7 Last
Synthesis, Characterization, and Photocatalytic Properties of Sol-Gel Ce-TiO2 Films
Lidija Ćurković, Debora Briševac, Davor Ljubas, Vilko Mandić, Ivana Gabelica
August 28, 2024 (v1)
Subject: Materials
Keywords: Ce-TiO2, characterization, ciprofloxacin, photocatalysis
In this study, nanostructured cerium-doped TiO2 (Ce-TiO2) films with the addition of different amounts of cerium (0.00, 0.08, 0.40, 0.80, 2.40, and 4.10 wt.%) were deposited on a borosilicate glass substrate by the flow coating sol-gel process. After flow coating, the deposited films were dried at a temperature of 100 °C for 1 h, followed by calcination at a temperature of 450 °C for 2 h. For the characterization of sol-gel TiO2 films, the following analytic techniques were used: X-ray diffraction (XRD), differential thermal analysis (DTA), thermal gravimetry (TG), differential scanning calorimetry (DSC), diffuse reflectance spectroscopy (DRS), and energy dispersive X-ray spectroscopy (EDS). Sol-gel-derived Ce-TiO2 films were used for photocatalytic degradation of ciprofloxacin (CIP). The influence of the amount of Ce in TiO2 films, the duration of the photocatalytic decomposition, and the irradiation type (UV-A and simulated solar light) on the CIP degradation were monitored. Kinetics... [more]
Broad-Spectrum Technical and Economic Assessment of a Solar PV Park: A Case Study in Portugal
António Farracho, Rui Castro
August 28, 2024 (v1)
Keywords: bifacial modules, DC–AC ratio, string length, tracking systems, utility-scale solar PV park
While technical optimization focuses on maximizing the annual energy yield of utility-scale PV parks, the ultimate goal for power plant owners is to maximize investment profit. This paper aims to bridge the gap between technical and economic approaches by using simulation data from a real-case utility-scale PV park. It analyzes how changes in configuration parameters such as the DC−AC ratio and string length and PV technologies like solar tracking systems and bifacial modules impact the economic metrics of the project, i.e., net present value (NPV) and internal rate of return (IRR). PVSyst software was utilized as a simulation tool, while in-house developed software implementing appropriate technical and economic models served as a comparison platform and was used to validate the outputs generated through PVSyst. Results indicate that the commonly used horizontal single-axis tracking configuration may economically underperform compared with fixed-tilt setups. The optimal DC−AC ratio fe... [more]
Research and Practice on Implementing Segmented Production Technology of Horizontal Well during Extra-High Water Cut Stage with Bottom Water Reservoir
Dong Zhang, Yanlai Li, Zongchao Zhang, Fenghui Li, Hongjie Liu
August 28, 2024 (v1)
Subject: Materials
Keywords: bottom water, extra-high water cut, horizontal well, segmented production technology
Bohai X oilfield has reached the extra-high water cut stage of more than 95%, dominated by the bottom water reservoir. The oilfield mainly adopts horizontal-well exploitation, with the characteristics of high difficulty and low success rate for well water plugging. To solve the above problem, the segmented production technology of horizontal wells was developed to guide oilfield applications and tap their potential. In the segmented design stage, the horizontal section is objectively segmented by drilling condition analysis, optimally based on drilling through interlayers or permeability discrepancy formation, simultaneously combined with the numerical simulation method. When implementing measures, annulus chemical packer materials are squeezed between segments to effectively inhibit the fluid flow between the open hole and the sand-packing screen pipe. Moreover, the packers are used to seal between segments to effectively restrain the flow between the screen and the central tube, achi... [more]
The Influence of Complex Piston Movement on the Output Flow Rate of a Hingeless Bent-Axis Axial Piston Pump
Junqiang Shi, Jiaxing Shi, Jingcheng Gao, Dongjing Chen, Xiaotao Li, Ying Li, Jin Zhang
August 28, 2024 (v1)
Keywords: correction factor, output flow rate, simulation analysis, swash-plate axial piston pump
Wobble-plate axial piston pumps, characterized by the lack of a slipper mechanism, experience reduced leakage in comparison to their swash-plate counterparts, which contributes to their higher volumetric efficiency. Presently, the primary focus of the research conducted by scholars both domestically and internationally is concentrated on wobble-plate axial piston pumps. The performance studies within this field are predominantly focused on investigating flow pulsation. They also investigate pressure pulsation. Additionally, they investigate cavitation phenomena. Research on inclined-axis axial piston pumps has been limited. This study focused on analyzing the operational form of the piston within an inclined-axis axial piston pump. A correction factor k was introduced based on the motion characteristics of the piston. The application of this factor significantly improved the accuracy of the simulations when compared to the experimental results. Specifically, at a load pressure of 10 MP... [more]
Towards Reliable Prediction of Performance for Polymer Electrolyte Membrane Fuel Cells via Machine Learning-Integrated Hybrid Numerical Simulations
Rashed Kaiser, Chi-Yeong Ahn, Yun-Ho Kim, Jong-Chun Park
August 28, 2024 (v1)
Keywords: electrochemical, fuel cell, limitations, Machine Learning, mass transfer, numerical modeling, PEMFC, progress
For mitigating global warming, polymer electrolyte membrane fuel cells have become promising, clean, and sustainable alternatives to existing energy sources. To increase the energy density and efficiency of polymer electrolyte membrane fuel cells (PEMFC), a comprehensive numerical modeling approach that can adequately predict the multiphysics and performance relative to the actual test such as an acceptable depiction of the electrochemistry, mass/species transfer, thermal management, and water generation/transportation is required. However, existing models suffer from reliability issues due to their dependency on several assumptions made for the sake of modeling simplification, as well as poor choices and approximations in material characterization and electrochemical parameters. In this regard, data-driven machine learning models could provide the missing and more appropriate parameters in conventional computational fluid dynamics models. The purpose of the present overview is to expl... [more]
Comparison of Tetraselmis suecica Cell Disruption Techniques: Kinetic Study and Extraction of Hydrosoluble Compounds
Hussein Rida, Jérôme Peydecastaing, Hosni Takache, Ali Ismail, Pierre-Yves Pontalier
August 28, 2024 (v1)
Subject: Biosystems
Keywords: Extraction, high-pressure homogenization, kinetics, microalgae, ultrasonication
The optimization of cell disruption is a critical step in microalgal biorefineries. We used the same batch of Tetraselmis suecica culture to compare two mechanical cell disruption techniques, focusing on the extraction yield of water-soluble molecules. The conditions for high-pressure homogenization (HPH) studied were two passes at a moderate pressure of 300 bars. For ultrasound (US) treatment, we used an amplitude of 20% (equivalent to 100 W) for 25 min. These conditions were chosen on the basis of a preliminary screen of extraction conditions. HPH extracted proteins and pigments more efficiently than US, whereas US was superior for uronic acid extraction. Interestingly, the two methods had similar extraction yields for carbohydrates under the studied conditions. We also analyzed the kinetics of molecule release by considering the centrifugation time lag for HPH and applying a first-order kinetic model for US. HPH outperformed US in terms of the immediate extraction and release of mol... [more]
Study on the Deactivation Mechanism of Ru/C Catalysts
Zhi Cao, Tianchi Li, Baole Li, Xiwen Chen, Chen Zuo, Weifang Zheng
August 28, 2024 (v1)
Keywords: deactivation mechanism, free radical site, Ru/C catalysts
Employing catalytic decomposition to break down reducing agents in intermediate-level radioactive waste during nuclear fuel reprocessing offers significant advantages. This study focuses on investigating the deactivation behavior of 5% Ru/C catalysts by two different synthesis processes used for reducing agent destruction. Deactivation experiments were conducted by subjecting the 5% Ru/C catalysts to 100 and 150 reaction cycles. Changes in the concentration of free radicals on the carbon-based carrier were measured to analyze the loading position and loss of Ru ions. Additionally, sorption−desorption curves and pore size distributions of the four catalysts were obtained. Analysis results reveal that Ru ions on the catalyst adsorb onto active free radical sites on the carbon-based carrier. Under ultrasonic conditions, some Ru ions partially desorb from the free radical sites on the carbon-based carrier, and desorbed Ru ions may adsorb onto weak free radical sites, while undesorbed Ru io... [more]
Production Feature Analysis of Global Onshore Carbonate Oil Reservoirs Based on XGBoost Classier
Guilin Qi, Baolei Liu
August 28, 2024 (v1)
Subject: Optimization
Keywords: carbonate reservoir, data mining, production feature, XGBoost
Carbonate reservoirs account for 60% of global reserves for oil, making them one of the most important types of sedimentary rock reservoirs for petroleum production. This study aimed to identify key production features that significantly impact oil production rates, enhancing reservoir management and optimizing production strategies. A comprehensive dataset is built from reserves and production history data of 377 onshore carbonate oilfields globally, encompassing features such as production, recovery rate, and recovery degree of the whole lifecycle of an oilfield. XGBoost classifier is trained by K-fold cross-validation and its hyperparameters are optimized by Optuna optimization framework. The results show that XGBoost has the best performance evaluated with metrics including accuracy, precision, recall, and F1 score comparing with decision tree, random forest, and support vector machine. Key production features are identified by analyzing the classification feature importance of XGB... [more]
A Lightweight Safety Helmet Detection Algorithm Based on Receptive Field Enhancement
Changpeng Ji, Zhibo Hou, Wei Dai
August 28, 2024 (v1)
Keywords: attention mechanism, lightweight, receptive field enhancement module, safety helmet detection, YOLOv5s
Wearing safety helmets is an important way to ensure the safety of workers’ lives. To address the challenges associated with low accuracy, large parameter values, and slow detection speed of existing safety helmet detection algorithms, we propose a receptive field-enhanced lightweight safety helmet detection algorithm called YOLOv5s-CR. First, we use a lightweight backbone, a high-resolution feature fusion network, and a small object detection layer to improve the detection accuracy of small objects while substantially decreasing the model parameters. Next, we embed a coordinate attention mechanism into the feature extraction network to improve the localization accuracy of the detected object. Finally, we propose a new receptive field enhancement module (RFEM) to substitute the SPPF module in the original network, enabling the model to acquire features under multiple receptive fields, thereby enhancing the detection precision of multi-scale objects. Using the Safety Helmet Detection da... [more]
Classification of Microseismic Signals Using Machine Learning
Ziyang Chen, Yi Cui, Yuanyuan Pu, Yichao Rui, Jie Chen, Deren Mengli, Bin Yu
August 28, 2024 (v1)
Keywords: classification, convolutional neural network, microseismic signals
The classification of microseismic signals represents a fundamental preprocessing step in microseismic monitoring and early warning. A microseismic signal source rock classification method based on a convolutional neural network is proposed. First, the characteristic parameters of the microseismic signals are extracted, and a convolutional neural network is constructed for the analysis of these parameters; then, the mapping relationship model between the characteristic parameters of the microseismic signals and the rock class is established. The feasibility of the proposed method in differentiating acoustic emission signals under different load conditions is verified by using acoustic emission data from laboratory uniaxial compression tests, Brazilian splitting tests, and shear tests. In the three distinct laboratory experiments, the proposed method achieved a source rock classification accuracy of greater than 90% for acoustic emission signals. The proposed and verified method provide... [more]
The Effect of Microbial Compound Fertilizer on the Heavy Metal Binding Forms and Enzyme Activity in Soil
Zheng Zhao, Changyin Huang, Baohui Liang, Siyu Wang, Huiwen Sun, Simeng Bian, Xiaoran Sun
August 28, 2024 (v1)
Subject: Biosystems
Keywords: heavy metal binding forms, heavy-metal-polluted soil, microbial compound fertilizer, physicochemical properties, soil enzyme activity
Nowadays, heavy metal pollution in soil caused by human production activities is increasingly serious. The heavy metal ions in soil inhibit plant growth and endanger human health as they can disrupt the physicochemical properties of soil. However, the elimination of heavy metals in soil is so difficult that more and more researchers are studying effective soil conditioners. The negatively charged groups in microbial communities can bind with heavy metal ions in the soil to remove them. In this paper, Cr- and Cd-polluted soils were used to simulate heavy-metal-polluted soil, and microbial compound fertilizer (MOF) was used as a soil conditioner for removing Cr and Cd in soil. The effects of different additive amounts of MOF on the physicochemical properties, the concentration of metal binding forms in soil and the enzyme activity of soil were investigated. The results showed that when the addition amount of fertilizer was 10%, the improvement effect on Cr- and Cd-polluted soils was the... [more]
Synthesis of Silver-Decorated Magnetite Nanoparticles Using Self-Assembly Methods
Gye Seok An
August 28, 2024 (v1)
Subject: Materials
Keywords: amino functionalization, magnetite (Fe3O4), self-assembly, silver (Ag) nanoparticles, superparamagnetic nanoparticle
This study investigated the synthesis and functional characteristics of Fe3O4@Ag core−shell nanoparticles, focusing on the impact of amino functionalization on their structural and chemical properties. Utilizing self-assembly methods driven by electrostatic interactions, we achieved the effective adsorption of Ag nanoparticles into Fe3O4 cores previously modified with silane (APTES) or polymer (PEI) precursors. Our results elucidate how the type of amino precursor affects the surface charge and subsequent adsorption dynamics, revealing that PEI-modified Fe3O4 nanoparticles exhibit more substantial Ag nanoparticle adsorption than those modified with APTES. This enhanced adsorption was attributed to the higher density of the amine groups introduced by PEI, which also affected the electrostatic properties of the nanoparticles, as evidenced by their zeta-potential values. Moreover, this study highlighted the role of electrostatic attraction in the self-assembly process, facilitating a cont... [more]
Recovery of High-Value Compounds from Yarrowia lipolytica IMUFRJ 50682 Using Autolysis and Acid Hydrolysis
Rhonyele Maciel da Silva, Bernardo Dias Ribeiro, Ailton Cesar Lemes, Maria Alice Zarur Coelho
August 28, 2024 (v1)
Subject: Materials
Keywords: antioxidant activity, Fourier transform infrared spectroscopy (FTIR), glycerol, mannoprotein, protein, thermogravimetry, ultrafiltration
This study aimed to evaluate the sequential hydrolysis of the biomass from unconventional and versatile Y. lipolytica to recover mannoproteins, carbohydrates, and other compounds as well as to determine the antioxidant activity of ultrafiltered fractions. The crude biomass underwent autolysis, and the resulting supernatant fraction was used for mannoprotein recovery via precipitation with ethanol. The precipitate obtained after autolysis underwent acid hydrolysis, and the resulting supernatant was ultrafiltered, precipitated, and characterized. The process yields were 55.5% and 46.14% for the crude biomass grown in glucose and glycerol, respectively. The mannoprotein with higher carbohydrate content (from crude biomass grown in glycerol) exhibited a higher emulsification index of 47.35% and thermal stability (60% weight loss). In contrast, the mannoprotein with higher protein content (from crude biomass grown in glucose) showed a better surface tension reduction of 44.50 mN/m. The tech... [more]
Adsorption and Diffusion Characteristics of CO2 and CH4 in Anthracite Pores: Molecular Dynamics Simulation
Yufei Gao, Yaqing Wang, Xiaolong Chen
August 28, 2024 (v1)
Keywords: anthracite, coalbed methane, diffusion coefficient, molecular dynamics simulation, radial distribution function
CO2-enhanced coalbed methane recovery (CO2-ECBM) has been demonstrated as an effective enhanced oil recovery (EOR) technique that enhances the production of coalbed methane (CBM) while achieving the goal of CO2 sequestration. In this paper, the grand canonical Monte Carlo simulation is used to investigate the dynamic mechanism of CO2-ECBM in anthracite pores. First, an anthracite pore containing both organic and inorganic matter was constructed, and the adsorption and diffusion characteristics of CO2 and CH4 in the coal pores under different temperature and pressure conditions were studied by molecular dynamics (MD) simulations. The results indicate that the interaction energy of coal molecules with CO2 and CH4 is positively associated with pressure but negatively associated with temperature. At 307.15 K and 101.35 kPa, the interaction energies of coal adsorption of single-component CO2 and CH4 are −1273.92 kJ·mol−1 and −761.53 kJ·mol−1, respectively. The interaction energy between ant... [more]
Simulation of Bubble Behavior Characteristics in a Rolling Fluidized Bed with the Addition of Longitudinal Internal Members
Rongsheng Xu, Ruojin Wang, Banghua Wu, Xiaopei Yuan, Dewu Wang, Yan Liu, Shaofeng Zhang
August 28, 2024 (v1)
Keywords: bubble flow, gas–solid fluidized bed, longitudinal internal members, Process Intensification, rolling condition
To address the effect of a ship’s rolling on the fluidization quality of fluidized beds, in this study, a simulation of a rolling fluidized bed with longitudinal internal members added (R-FBLIM) was carried out and compared with that of a rolling fluidized bed without internal members added (R-FBWIM). The transient motion, as well as the behavioral characteristics of the bubbles within the R-FBLIM, was analyzed; the variation patterns of the number of bubbles, as well as the equivalent diameter of the bubbles, were compared for different apparent gas velocities, oscillation periods, and amplitudes; and the mechanism of the action of the longitudinal internal members was investigated. The results show that the structural design of the longitudinal internal members can effectively improve the gas−solid fluidization quality of the rolling fluidized bed. The horizontal support plate and the cap hole structure can effectively break the air bubbles, the cap hole structure promotes the radial... [more]
Green Supply Chain Optimization Based on Two-Stage Heuristic Algorithm
Chunrui Lei, Heng Zhang, Xingyou Yan, Qiang Miao
August 28, 2024 (v1)
Keywords: brainstorming optimization algorithm, green supply chain management, logistics planning, supply chain optimization
Green supply chain management is critical for driving sustainable development and addressing escalating environmental challenges faced by companies. However, due to the multidimensionality of cost−benefit analysis and the intricacies of supply chain operations, strategic decision-making regarding green supply chains is inherently complex. This paper proposes a green supply chain optimization framework based on a two-stage heuristic algorithm. First, anchored in the interests of intermediary core enterprises, this work integrates upstream procurement and transportation of products with downstream logistics and distribution. In this aspect, a three-tier green complex supply chain model incorporating economic and environmental factors is developed to consider carbon emissions, product non-conformance rates, delay rates, and transportation costs. The overarching goal is to comprehensively optimize the trade-off between supply chain costs and carbon emissions. Subsequently, a two-stage heur... [more]
Mus4mCPred: Accurate Identification of DNA N4-Methylcytosine Sites in Mouse Genome Using Multi-View Feature Learning and Deep Hybrid Network
Xiao Wang, Qian Du, Rong Wang
August 28, 2024 (v1)
Keywords: bioinformatics, deep learning, DNA N4-methylcytosine sites, feature fusion
N4-methylcytosine (4mC) is a critical epigenetic modification that plays a pivotal role in the regulation of a multitude of biological processes, including gene expression, DNA replication, and cellular differentiation. Traditional experimental methods for detecting DNA N4-methylcytosine sites are time-consuming, labor-intensive, and costly, making them unsuitable for large-scale or high-throughput research. Computational methods for identifying DNA N4-methylcytosine sites enable the rapid and cost-effective analysis of DNA 4mC sites across entire genomes. In this study, we focus on the identification of DNA 4mC sites in the mouse genome. Although there are already some computational methods that can predict DNA 4mC sites in the mouse genome, there is still significant room for improvement in accurately predicting them due to their inability to fully capture the multifaceted characteristics of DNA sequences. To address this issue, we propose a new deep learning predictor called Mus4mCP... [more]
Study of Draft Tube Optimization Using a Neural Network Surrogate Model for Micro-Francis Turbines Utilized in the Water Supply System of High-Rise Buildings
Qilong Xin, Jianmin Wu, Jiyun Du, Zhan Ge, Jinkuang Huang, Wei Yu, Fangyang Yuan, Dongxiang Wang, Xinjun Yang
August 28, 2024 (v1)
Keywords: draft tube, Francis turbine, high-rise buildings, radial basis function neural network, water supply system
With the increasing popularity of clean energy, the use of micro turbines to recover surplus energy in the water supply pipelines of high-rise buildings has attracted more attention. This study adopts a predictor model based on Radial Basis Function Neural Network (RBFNN) to optimize the draft tube shape for micro-Francis turbines. The predictor model is formed on a dataset provided by numerical simulations, which are validated by lab tests. Specifically, numerical investigations are carried out in the shape of a draft tube to determine an optimal model. Additionally, the superiority of the RBFNN model in nonlinear optimization is verified by comparing it with other models under the same date sets. After that, the design parameters are optimized using RBFNN and sequential quadratic programming algorithm (SQPA). Finally, the turbine prototype is fabricated and tested on a lab test rig. The experimental results indicate that the numerical method adopted in this research is accurate enoug... [more]
Assessment of Wearable Cooling and Dehumidifying System Used under Personal Protective Clothing through Human Subject Testing
Yiying Zhou, Lun Lou, Jintu Fan
August 28, 2024 (v1)
Keywords: healthcare workers, personal protective equipment, thermal comfort, wearable cooling and dehumidifying system, wearing comfort
Healthcare professionals wearing personal protective equipment (PPE) during outbreaks often experience heat strain and discomfort, which can negatively impact their work performance and well-being. This study aimed to evaluate the physiological and psychological effects of a newly designed wearable cooling and dehumidifying system (WCDS) on healthcare workers wearing PPE via a 60 min treadmill walking test. Core temperature, mean skin temperature, heart rate, and subjective assessments of thermal sensation, wetness sensation, and thermal comfort were measured throughout the test. Additionally, ratings of wearing comfort and movement comfort were recorded during a wearing trial. The results showed that the WCDS significantly reduced core temperature, improved thermal sensation, and reduced wetness sensation compared to the non-cooling condition. The microclimatic temperature within the PPE was significantly lower in the cooling condition, indicating the WCDS’s ability to reduce heat bui... [more]
Experimental Analysis of the Mechanical Properties and Failure Behavior of Deep Coalbed Methane Reservoir Rocks
Haiyang Wang, Shugang Yang, Linpeng Zhang, Yunfeng Xiao, Xu Su, Wenqiang Yu, Desheng Zhou
August 28, 2024 (v1)
Subject: Materials
Keywords: compressive strength of rock, deep coalbed methane reservoir, failure behavior, kaolinite, rock mechanical properties
A comprehensive understanding of the mechanical characteristics of deep coalbed methane reservoir rocks (DCMRR) is crucial for the safe and efficient development of deep coalbed gas resources. In this study, the microstructural and mechanical features of the coal seam roof, floor, and the coal seam itself were analyzed through laboratory experiments. The impact mechanisms of drilling fluid and fracturing fluid hydration on the mechanical properties and failure behavior of coal seam rocks were investigated. The experimental results indicate that the main minerals in coal seams are clay and amorphous substances, with kaolinite being the predominant clay mineral component in coal seam rocks. The rock of the coal seam roof and floor exhibits strong elasticity and high compressive strength, while the rock in the coal seam section shows a lower compressive capacity with pronounced plastic deformation characteristics. The content of kaolinite shows a good correlation with the mechanical prope... [more]
Development of Macro-Encapsulated Phase-Change Material Using Composite of NaCl-Al2O3 with Characteristics of Self-Standing
Shenghao Liao, Xin Zhou, Xiaoyu Chen, Zhuoyu Li, Seiji Yamashita, Chaoyang Zhang, Hideki Kita
August 28, 2024 (v1)
Subject: Materials
Keywords: encapsulated phase-change material, enhanced thermal conductivity, high durability, molten salt, self-standing
Developing thermal storage materials is crucial for the efficient recovery of thermal energy. Salt-based phase-change materials have been widely studied. Despite their high thermal storage density and low cost, they still face issues such as low thermal conductivity and easy leaks. Therefore, a new type of NaCl-Al2O3@SiC@Al2O3 macrocapsule was developed to address these drawbacks, and it exhibited excellent rapid heat storage and release capabilities and was extremely stable, significantly reducing the risk of leakage at high temperatures for industrial waste heat recovery and in concentrated solar power systems above 800 °C. Thermal storage macrocapsules consisted of a double-layer encapsulation of silicon carbide and alumina and a self-standing core of NaCl-Al2O3. After enduring over 1000 h at a high temperature of 850 °C, the encapsulated phase-change material exhibited an extremely low weight loss rate of less than 5% compared with NaCl@Al2O3 and NaCl-Al2O3@Al2O3 macrocapsules, for... [more]
Three-Dimensional Heterogeneous Salt Cavern Underground Gas Storage Water Solution Cavity Model Study
Xueqi Cen, Xinggang Meng, Zongxiao Ren, Jiajun Cao
August 28, 2024 (v1)
Keywords: gas storage, morphology prediction, salt cavern, water-soluble cavity building model
In recent years, with the rapid development of salt cavern gas storage reservoir construction in China, the characteristics of salt rock reservoirs with strong non-homogeneity and many interlayers have brought challenges to the dynamic prediction of water solution cavity construction. Aiming to solve this problem, this paper constructs a three-dimensional non-homogeneous salt cavern reservoir water-soluble cavity building prediction model, which takes into full consideration the non-homogeneity of salt rock reservoirs, interlayers, reservoir temperatures, and water injection process parameters, among other factors. By comparing the calculation results of the software compiled by the model with those of other numerical simulation software, we show that the model can accurately reflect the influence of geological parameters on the cavity morphology under the condition of non-uniform geological parameters, with higher simulation accuracy, and ultimately analyze individual examples. It can... [more]
A Fractional Creep Model for Deep Coal Based on Conformable Derivative Considering Thermo-Mechanical Damage
Lei Zhang, Chunwang Zhang, Ke Hu, Senlin Xie, Wenhao Jia, Lei Song
August 28, 2024 (v1)
Subject: Materials
Keywords: conformable derivative, deep coal, fractional creep model, thermo-mechanical damage
In deep high-geostress and high-temperature environments, understanding the creep deformation of deep coal is of great significance for effectively controlling coal deformation and improving gas control efficiency. In this paper, the Abel dashpot is defined based on the conformable derivative, and a damage variable is introduced into the conformable derivative order, thereby constructing a damaged Abel dashpot. Combining the Weibull distribution and the Drucker−Prager yield criterion, the thermo-mechanical coupling damage variable is defined, and the coupling damage variable is introduced into the damaged Abel dashpot to establish a thermo-mechanical coupling damaged Abel dashpot. Based on the traditional framework of the Burgers creep model, a three-dimensional fractional creep model of deep coal considering the influence of thermo-mechanical coupling damage is proposed. Experimental data on coal creep under different temperatures and stress conditions are utilized to validate the eff... [more]
Bioprocess Design and Evaluation of Hydrothermal Hydrolysates from Sargassum sp. for Enhancing Arthrospira platensis Growth and Protein Content
Alejandra Cabello-Galindo, Rosa M. Rodríguez-Jasso, Gabriela Cid-Ibarra, K. D. González-Gloria, Ruth Belmares, Mayela Govea-Salas, Luciane Maria Colla, Héctor A. Ruiz
August 28, 2024 (v1)
Keywords: Biomass, biorefinery, blue biotechnology, circular bioeconomy, cyanobacteria, mixotrophic cultivation
The proliferation of Sargassum biomass in various coastal areas has led to environmental and socio-economic problems. However, due to their unique composition, these biomasses offer versatile applications, prompting research into their potential in third-generation biorefineries. In this study, the hydrothermal processing of Sargassum sp. was evaluated under specific conditions at 190 °C/50 min and 150 °C/30 min. The resulting hydrolysates (liquid phase) were used as alternative culture media for cultivation. Nine treatments for the cultivation of Arthrospira platensis were assessed, varying the concentration of hydrothermal hydrolysates (HH) at 190 °C/50 min: T1 (5% v/v), T2 (10% v/v), and T3 (15% v/v). T4 (5% v/v), T5 (10% v/v), and T6 (15% v/v), maintaining the same HH conditions, and with the addition of 0.7 g/L NaNO3; and treatments T7, T8, and T9 had concentrations of 5%, 10%, and 15% of HH, respectively, at 150 °C/30 min with the addition of 0.7 g/L NaNO3, respectively. Each tre... [more]
Research and Application of Non-Steady-State CO2 Huff-n-Puff Oil Recovery Technology in High-Water-Cut and Low-Permeability Reservoirs
Zhenjun Wang, Zhufeng Wang, Wenli Luo, Songkai Li, Shisheng Liang, Xianfeng Wang, Xiaohu Xue, Naikun Tu, Shudong He
August 28, 2024 (v1)
Subject: Materials
Keywords: CO2 huff-n-puff, low-permeability reservoir, non-steady state, on-site pilot test
In response to the issues of poor water flooding efficiency, low oil production rates, and low recovery rates during the high-water-cut period in the low-permeability reservoirs of the Mutou Oilfield, the non-steady-state (NSS) CO2 huff-n-puff oil recovery technology was explored. The NSS CO2 huff-n-puff can improve the development effect of low-permeability reservoirs by replenishing the reservoir energy and significantly increasing the crude oil mobility. Experimental investigations were carried out, including a crude oil and CO2−crude oil swelling experiment, minimum miscibility pressure testing experiment, high-temperature and high-pressure microfluidic experiment, and NSS CO2 huff-n-puff oil recovery on-site pilot test. The experimental results showed that the main mechanisms of NSS CO2 huff-n-puff include dissolution, expansion, viscosity reduction, and swept volume enlargement, which can effectively mobilize the remaining oil from the various pore throats within the reservoir. T... [more]
Showing records 51 to 75 of 1591. [First] Page: 1 2 3 4 5 6 7 Last