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Showing records 226 to 250 of 263. [First] Page: 6 7 8 9 10 11 Last
Optimizing Photovoltaic Power Production in Partial Shading Conditions Using Dandelion Optimizer (DO)-Based MPPT Method
Injila Sajid, Ayushi Gautam, Adil Sarwar, Mohd Tariq, Hwa-Dong Liu, Shafiq Ahmad, Chang-Hua Lin, Abdelaty Edrees Sayed
January 5, 2024 (v1)
Keywords: dandelion optimizer, maximum power point tracking, metaheuristic, solar PV
This research proposes the dandelion optimizer (DO), a bioinspired stochastic optimization technique, as a solution for achieving maximum power point tracking (MPPT) in photovoltaic (PV) arrays under partial shading (PS) conditions. In such scenarios, the overall power output of the PV array is adversely affected, with shaded cells generating less power and consuming power themselves, resulting in reduced efficiency and local hotspots. While bypass diodes can be employed to mitigate these effects by redirecting current around shaded cells, they may cause multiple peaks, making MPPT challenging. Therefore, metaheuristic algorithms are suggested to effectively optimize power output and handle multiple peaks. The DO algorithm draws inspiration from the long-distance movement of a dandelion seed, which relies on the force of the wind. By utilizing this bioinspired approach, the DO algorithm can successfully capture the maximum power point (MPP) under different partial shading scenarios, wh... [more]
Process Simulation and Integration of Natural Gas Condensate Recovery Using Ethane−Propane Refrigerant Mixture
Jin Sun, Rujin Zhou, Li Wang, Xinye Zeng, Shaolin Hu, Haoshui Yu, Liangliang Jiang
January 5, 2024 (v1)
Keywords: Aspen HYSYS, combined refrigeration, Optimization, process simulation
Separating heavy components from natural gas not only enhances safety, improves pipeline transportation, ensures product quality, and addresses environmental considerations, but it also exerts an influence on global energy trends. Therefore, separating heavy components is necessary and can result in beneficial goods. This article presents a comprehensive study on the process simulation and optimization of the recovery of natural gas condensate via the combined refrigeration of a mixture of ethane and propane as a refrigerant. The optimization objectives include maximizing the recovery of ethane and propane, minimizing energy consumption, and achieving desired product quality targets. A sensitivity analysis was performed to assess the impact of key parameters on process performance. Using Aspen HYSYS software, the influence of the cooler outlet stream temperature and expander outlet stream pressure on the shaft power and profit of a dry gas compressor was analyzed based on the operating... [more]
Fault Detection and Location of 35 kV Single-Ended Radial Distribution Network Based on Traveling Wave Detection Method
Xiaowei Xu, Fangrong Zhou, Yongjie Nie, Wenhua Xu, Ke Wang, Jian OuYang, Kaihong Zhou, Shan Chen, Yiming Han
January 5, 2024 (v1)
Keywords: 35 kV, distribution network, Fault Detection, traveling wave method, wavelet conversion method
With the progress of society and the iterative improvement of infrastructure construction, the power grid transmission lines have also entered an era of intelligence. The national distribution system has made ensuring the regular operation of the distribution network as well as prompting troubleshooting and detection its top priority. Research on fault diagnosis for 35 kV single-ended radial distribution networks is still in its infancy compared to other hot topics in the industry, such as short-circuit fault detection and fault node localization. This study adopts the 35 kV single-ended radial distribution network as a model, detects fault lines via the traveling wave method, and accurately locates fault nodes using the wavelet conversion method, hoping to quickly identify and locate fault nodes in distribution networks. The experimental results demonstrate that the research method can quickly identify the faulty line and carry out further fault node location detection. The final obta... [more]
Research on the Evaluation of Emergency Management Synergy Capability of Coal Mines Based on the Entropy Weight Matter-Element Extension Model
Chaolun Sun, Yu Hao, Jianping Wei, Lijun Zhang
January 5, 2024 (v1)
Keywords: coal mine accident, emergency coordination, evaluation system, level of emergency management, the entropy weight matter-element extension model
Emergency management synergy capability is not only a “touchstone” to measure the operation effect of the emergency system of coal mine enterprises, it is an important symbol to reflect its level. In order to improve the level of emergency management in coal mines based on the PPRR theory of crisis management cycle, in this paper a hierarchical evaluation index system is constructed based on the emergency management process. A quantitative evaluation model of emergency synergy capacity is proposes based on the entropy−weighted elemental topology method to conduct evaluation and model validation for the case of J coal mine in Henan Province. The results show that the overall evaluation of the emergency management synergy capability of J Coal Mine is at a “good” level, with the emergency prevention synergy capability, emergency preparedness synergy capability, and recovery and reconstruction synergy capability at a “good” level and the emergency response synergy capability is at a “avera... [more]
Factor Analysis of the Physical−Mechanical Properties for Geopolymers Based on Brick Dust and Biomass Bottom Ash as Eco-Friendly Building Materials
Juan María Terrones-Saeta, Ana Teresa Luís, Emilio Romero, Juan Carlos Fortes Garrido, Jesús Diaz-Curiel, José Antonio Grande
January 5, 2024 (v1)
Subject: Materials
Keywords: ceramic, circular mining, construction materials, data mining, factorial analysis, geopolymer, structures, wastes
The production of building materials is unavoidable if the well-being and development of society are to be maintained. However, in manufacturing these materials, significant greenhouse gas emissions and environmental effects are produced. For this reason, and with the aim of reducing the impact of the manufacture of these materials, this work developed a geopolymeric material made up solely of wastes, brick dust and biomass bottom ashes which replaced the traditional ceramic materials. To evaluate the quality of this sustainable geopolymeric material, different groups of specimens were formed with different percentages of both residues, subsequently determining the physical properties of the new-formed geopolymers and guaranteeing they accomplish the prescriptions of the ceramic regulations for construction. In addition, the results of the geopolymer characterisation tests were statistically analysed using factor analysis, with the sole purpose of establishing connections and interdepe... [more]
Earthworm (Perionyx excavatus) Protein Hydrolysate: Hypoglycemic Activity and Its Stability for the Hydrolysate and Its Peptide Fractions
Phong T. Bui, Khoa T. Pham, Tam D. L. Vo
January 5, 2024 (v1)
Subject: Biosystems
Keywords: antidiabetic activity, earthworm protein, earthworm protein hydrolysate, hypoglycemic activity, peptide fraction, α-amylase inhibitory activity, α-glucosidase inhibitory activity
This study aims at exploring earthworm protein hydrolysate and its peptide fractions as a potential hypoglycemic agent by inhibiting α-amylase and α-glucosidase. Firstly, the best hydrolysis conditions to gain the hydrolysates with the highest α-amylase inhibitory activity (α-AIA) and α-glucosidase inhibitory activity (α-GIA) were figured out using a one-factor test. Next, the stability of the hypoglycemic activity of the hydrolysates and their 5 peptide fractions recovered using ultrafiltration membranes were assessed by employing the tests of in vitro digestion, thermal, and pH treatment. The results showed that at the best hydrolysis conditions, the hydrolysates exhibited α-AIA of 91.30 ± 2.51% and α-GIA of 44.69 ± 0.47%. Specifically, the <1 kDa peptide fraction from the hydrolysate expressed a greater α-AIA than that of acarbose, with nearly the same α-GIA as that of voglibose. The α-AIA and α-GIA of the hydrolysates and their fractions were enhanced after the in vitro digestio... [more]
Stability Analysis: Two-Area Power System with Wind Power Integration
Aldo Barrueto Guzmán, Héctor Chávez Oróstica, Karina A. Barbosa
January 5, 2024 (v1)
Keywords: coherency, dynamic equivalents, frequency response model, low-inertia power systems, synthetic inertia
This paper focuses on a comprehensive stability study of a two-area power system with wind power integration and synthetic inertia control in each area, considering the effects of varying the interconnection link. Normally, synthetic inertia proposals are analyzed in one-area systems, in which stability is tested without considering transmission system phenomena, such as coherency. As modern power systems are progressively becoming interconnected, the possibility of forming two or more non-coherent areas is likely, which poses a challenge to synthetic inertia control techniques that use system frequency as a main feedback signal. In this context, this work addresses a crucial gap in the existing literature and provides a valuable starting point for studying more complex interconnected power systems with wind power integration. Simulations were performed in Matlab-Simulink considering a data-driven frequency dynamics model of the Chilean Electric System, and a wind power model with synt... [more]
Experimental Studies of Methane Adsorption on Activated Carbon and 3D Graphene Materials
Ziwen Zhu, Muyuan Zhang
January 5, 2024 (v1)
Subject: Materials
Keywords: 3D graphene materials, activated carbon, Adsorption, carbon-based materials, methane storage
Two kinds of slit pore carbon materials, namely activated carbon (AC) and 3D graphene materials (3D-GS), were purchased to examine their methane storage capabilities. The structural analysis and characterization of AC and 3D-GS were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), the X-ray energy dispersive spectrum (EDS), and N2 adsorption/desorption isotherms. Additionally, a thermodynamic framework was employed in the Henry’s law region to evaluate the potential well between the adsorbed fluid and adsorbent. The adsorption behavior of methane on two materials at room temperature and high pressure was also investigated. The results show that the Toth equation is the most suitable model for predicting adsorption isotherms than the Langmuir and L-F equations and determines that the absolute uptake of methane storage on AC and 3D-GS are, respectively, 7.86 mmol·g−1 and 8.9 mmol·g−1 at 298 K and 35 bar. In the Henry’s law region, the isosteric heat of metha... [more]
Preliminary Results of Innovative Two-Stage Torrefaction Technology Applied for Thermochemical Treatment of Sunflower Husk
Artemy Nebyvaev, Dmitry Klimov, Artem Ryzhenkov, Mathieu Brulé
January 5, 2024 (v1)
Keywords: ash deposits, biomass combustion, torrefaction
This article proposes an innovative two-stage technology for biomass torrefaction generating high-quality biochar, more specifically biocoal, as solid fuel, and offering a promising solution to the challenges posed by the combustion of biomass. In particular, the higher quality of biochar as solid fuel reduces the build-up of unmanageable deposits on fired surfaces, as these deposits inhibit heat transfer and reduce the efficiency of biomass boilers. The proposed two-stage technology involves torrefaction in a hearth-type reactor at temperatures up to 250 °C, followed by a subsequent stage of cooling achieved through washing with water. The two-stage torrefaction technology is integrated within a vertical hearth reactor vessel composed of three superimposed trays serving for biomass input, torrefaction, and water washing combined with biomass cooling, respectively. Upon contact with torrefied biomass, cooling water turned into water vapor; hence, eliminating the requirement for subsequ... [more]
Mass and Heat Transfer of Pressure Swing Adsorption Oxygen Production Process with Small Adsorbent Particles
Yuan Sun, Chuanzhao Zhang, Xianqiang Zhu, Liang Dong, Xianhang Sun
January 5, 2024 (v1)
Keywords: air separation, mass transfer, numerical analysis, pressure swing adsorption, rapid cycle
Rapid-cycle pressure swing adsorption (PSA) with small adsorbents particles is intended to improve mass transfer rate and productivity. However, the mass transfer mechanisms are changed with reduction of particle size during rapid-cycle adsorption process. A heat and mass transfer model of rapid-cycle PSA air separation process employing small LiLSX zeolite particles is developed and experimentally validated to numerically analyze the effects of mass transfer resistances on the characteristics of cyclic adsorption process. Multicomponent Langmuir model and linear driving force model are employed for characterizing the adsorption equilibrium and kinetic. The results of numerical analysis demonstrate that the dominant mass transfer resistance of small adsorbents particles is a combination of film resistance, axial dispersion effect and macropore diffusion resistance. The oxygen purity, recovery and productivity of the product are overestimated by ~2−4% when the effect of axial dispersion... [more]
Optimal Layout Methods for Deep Chamber to Separate Coal and Gangue Based on the Weak Stratum Horizon
Cheng Zhu, Yong Yuan, Hanqing Sun, Zhongshun Chen, Wenmiao Wang
January 5, 2024 (v1)
Keywords: coal–gangue separation chamber, deformation and failure law, optimal layout methods, structure characteristics, weak stratum horizon
Aiming at the optimal layout of a deep chamber for coal−gangue separation (DCCS) based on the weak stratum horizon, an in-depth study was carried out by combining field investigations, model tests, and numerical simulations. Firstly, the main structural characteristics of DCCS were summarized. Then, the deformation and failure law for rocks surrounding DCCS were revealed under different horizons in the weak stratum. Finally, the optimal layout methods of DCCS based on the thickness and horizon in the weak stratum were determined in different in situ stresses, using the proposed comprehensive evaluation method for surrounding-rock stability. The results show that if the thickness of the weak stratum was small, the side near the roof of DCCS should be arranged along the weak stratum when the lateral pressure coefficient was λ < 0.6 or λ > 1. The side near the floor of DCCS was arranged along the weak stratum when 0.6 ≤ λ ≤ 1 and the surrounding-rock stability was the best. If the thickne... [more]
Paleo-Sedimentary Environments and Controlling Factors for Enrichment of Organic Matter in Alkaline Lake Sediments: A Case Study of the Lower Permian Fengcheng Formation in Well F7 at the Western Slope of Mahu Sag, Junggar Basin
Gangqiang Chen, Yuantao Tang, Yuhang Nan, Fan Yang, Dongyong Wang
January 5, 2024 (v1)
Subject: Environment
Keywords: depositional environment, Fengcheng formation, Junggar Basin, major elements, organic matter enrichment, trace elements
The Lower Permian Fengcheng formation is a significant source of rocks and a reservoir for the Mahu Sag in the Junggar Basin. Recently, the paleo-environment deposition factors of the P1f formation have become a popular research topic. This research was conducted using data from the F7 well of Mahu Sag, based on the geochemical analysis results of TOC (total organic carbon), REE (rare earth elements), and major and trace elements of 53 samples from P1f (Lower Permian Fengcheng formation), and some deposition factors are discussed. The P1f deposition process was classified into four stages based on paleo-environment elemental indicators. This research describes the deposition process of the evolution of alkaline lakes. The early and preliminary stages of alkali lake evolution are considered as late P1f1 to middle P1f2; the paleoclimate of this process was dry, the reduction conditions increased, and the paleo-productivity and lake salinity were enhanced. The terminal stage of alkali lak... [more]
Design of Radial Flow Channel Proton Exchange Membrane Fuel Cell Based on Topology Optimization
Cheng Qu, Yifan Zhang, Zhihu Zhang, Minggang Zheng
January 5, 2024 (v1)
Keywords: average depth model, PEMFC, radial flow channel, topological optimization, volume constraints
In this paper, the flow channel of the radial proton exchange membrane fuel cell (PEMFC) is optimized by the topological optimization method. Using the SNOPT algorithm, a two-dimensional stable constant temperature model is freely constructed in the cyclic sector design domain. Topology optimization aims to maximize the efficiency of PEMFC and minimize the energy dissipation of reaction gas. We analyze radial topology flow channels’ mass transfer capacity and cell performance with different maximum volume constraints. The results show that under high current density, the performance of the optimized channel is significantly better than that of the traditional channel. Increasing the maximum volume constraint is beneficial for improving the mass transfer of PEMFC. At 0.6 V, the cell performance of Scheme 4 is 14.9% higher than the serpentine flow channel and 9.5% higher than the parallel flow channel. In addition, in the optimal selection, 3D simulation modeling is carried out for more... [more]
Seismic Response Variance of Depositional Sequences: Implications for Reservoir Prediction in Lacustrine Basin
Qiaolin He, Shuwen Yang, Wenxiang He, Yong Hu, Tong Wang, Xiaoyang Gao
January 5, 2024 (v1)
Keywords: Baxigai Formation, depositional model, seismic forward modeling, Tabei Uplift, Tarim Basin, wavelet decomposition
In recent years, lithologic oil and gas reservoirs have become an important target in continental hydrocarbon-bearing basins. Geophysical prospecting technology using seismic data is an indispensable tool for oil and gas exploration. However, while previous work has paid much attention to the seismic responses of reservoirs (sandstones), the seismic responses of depositional sequences composed of sandstone−mudstone cycles are not well understood in reservoir prediction. This problem seriously restricts efficient oil−gas exploration and development. The Cretaceous Baxigai Formation in the Yingmaili area, west of the Tabei Uplift, is an important exploration target for lithologic oil and gas reservoirs in the Tarim Basin. The Baxigai Formation is deeply buried with thin thickness. The Baxigai Formation in the study area is divided into a lower sandstone section and an upper mudstone section. Braided river delta sand bodies are developed in the lower sandstone section, and braided river d... [more]
Study of the Effect of Eudragit RSPO on the Photostability of Venlafaxine in a Physical Mixture and in a Melt Form
Anna Maślanka, Marek Szlósarczyk, Przemysław Talik, Joanna Szafraniec-Szczęsny, Krzysztof Woyna-Orlewicz, Paweł Żmudzki, Urszula Hubicka
January 5, 2024 (v1)
Subject: Materials
Keywords: DSC, eudragit, excipients, kinetic studies, photodegradation, photostability, solid dosage, UHPLC/MS/MS, venlafaxine
The effect of Eudragit RSPO on the photostability of venlafaxine in a physical mixture and as a melt was studied. A validated ultra-high-performance liquid chromatography mass spectrometry method was used to determine the content of venlafaxine alongside degradation products. The most likely structures of the degradation products were determined by mass spectrometry. The samples were evaluated before and after exposure to ultraviolet A by differential scanning calorimetry and scanning electron microscopy. The kinetic parameters of the decomposition of venlafaxine in the physical mixture and melt form were calculated and comparable to those of venlafaxine as an active pharmaceutical ingredient. The results indicate that the process of venlafaxine decomposition is more than three times slower in the venlafaxine−eudragit melt than in its physical mixture with eudragit and its pure form. The strong photoprotective nature of the tested polymer against venlafaxine in the melt form was also c... [more]
Analysis of the Current Status and Hot Technologies of Coal Spontaneous Combustion Warning
Feiran Wang, Zhansuo Ji, Haiyan Wang, Yue Chen, Tao Wang, Ruoyi Tao, Chang Su, Guchen Niu
January 5, 2024 (v1)
Keywords: coal spontaneous combustion warning, marker gas, VOSviewer, warning model
Coal spontaneous combustion disasters are one of the most serious types of mine disasters in China at present, posing a huge threat to underground personal safety and coal production operations. In order to prevent and control coal spontaneous combustion hazards and construct an efficient early warning system, this paper presents a review of coal spontaneous combustion early warning based on the Web of Science database search of 583 papers related to coal spontaneous combustion early warning collected from 2002 to 2021, using VOSviewer visualization software. The number of publications and partnerships at the author, institution and country levels are obtained, and the research hotspots in the field of coal spontaneous combustion warning are obtained based on keyword co-occurrence and clustering. The results show that the research results of scholars with a high publication volume have significant influence in the field of coal spontaneous combustion warning and prevention and control,... [more]
Preparation of a New Adsorbent Material from Agro-Industrial Waste and Comparison with Commercial Adsorbent for Emerging Contaminant Removal
Luís Fernando Cusioli, Daniel Mantovani, Rosângela Bergamasco, Angelo Marcelo Tusset, Giane Gonçalves Lenzi
January 5, 2024 (v1)
Subject: Materials
Keywords: emerging contaminants, product quality, production cost, sustainable material
An adsorbent was developed from agro-industrial residues derived from the seed husks of Moringa oleifera Lam., in which the hydrochar process was used as it is a sustainable, low-cost and easy-to-operate process. In comparison, a commercial adsorbent, activated charcoal from babaçu coconut, was used. Both materials were characterized using SEM, FTIR, zeta potential and BET, showing their morphologies, chemical compositions and textural analyses that proved the adsorption capacity of each material. A cost study was also carried out regarding the production of the materials. For both materials, an equilibrium study was carried out using the following contaminants: metformin, diuron, methylene blue and lead. We aimed to study the use of agro-industrial waste as a new adsorbent material, which was shown to have an average removal for all the contaminants tested of around 84.56−99.13%. The new adsorbent developed had many interactions with the studied contaminants, allowing its use on a lar... [more]
A Hybrid Ultrasonic Membrane Anaerobic System (UMAS) Development for Palm Oil Mill Effluent (POME) Treatment
Nour Hamid Abdurahman, Yunus Mohd Rosli, Nour Hamid Azhari, Gasim Hayder, Ismail Norasyikin
January 5, 2024 (v1)
Subject: Environment
Keywords: anaerobic, COD removal, kinetics equations, membrane, POME, ultrasonic
The high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) levels in palm oil mill effluent (POME) wastewater make it an environmental contaminant. Moreover, conventional POME wastewater treatment approaches pose economic and environmental risks. The present study employed an ultrasonic membrane anaerobic system (UMAS) to treat POME. Resultantly, six steady states were procured when a kinetic assessment involving 11,800−21,700 mg·L−1 of mixed liquor suspended solids (MLSS) and 9800−16,800 mg·L−1 of mixed liquor volatile suspended solids (MLVSS) was conducted. The POME treatment kinetics were explained with kinetic equations derived by Monod, Contois and Chen and Hashimoto for organic at loading rates within the 1−11 kg·COD·m−3·d−1 range. The UMAS proposed successfully removed 96.6−98.4% COD with a 7.5 day hydraulic retention time. The Y value was 0.67 g·VSS/g·COD, while the specific micro-organism decay rate, b was 0.24 day−1. Methane (CH4) gas production ranged from 0.2... [more]
Research on Path Tracking and Yaw Stability Coordination Control Strategy for Four-Wheel Independent Drive Electric Trucks
Feng Gao, Fengkui Zhao, Yong Zhang
January 5, 2024 (v1)
Keywords: four-wheel independent drive, fractional order sliding mode control, linear quadratic regulator, path tracking, yaw stability control
Achieving accurate path tracking and vehicle stability control for four-wheel independent drive electric trucks under complex driving conditions, such as high speed and low adhesion, remains a major challenge in current research. Poor coordination control may cause the vehicle to deviate from its intended path and become unstable. To address this issue, this article proposes a coordinated control strategy consisting of a three-layer control framework. In the upper layer controller design, establish a linear quadratic regulator (LQR) path tracking controller to ensure precise steering control by eliminating steady-state errors through feedforward control. The middle layer controller utilizes the fractional order sliding mode control (FOSMC) yaw moment controller to calculate the additional yaw moment based on the steering angle of the upper input, utilizing the error of yaw rate and sideslip angle as the state variable. To collectively optimize the control system, establish a coordinate... [more]
Response and Mechanism of Coal Fine Production to Differential Fluid Action in the Baode Block, Ordos Basin
Boyang Wang, Yunfei Cui, Jingjing Li, Junjian Zhang, Longhui Bai, Liu Wang
January 5, 2024 (v1)
Keywords: Baode Block, coal fine, fluid action, fractal dimension, reservoir damage
The Baode Block in the Ordos Basin is currently one of the most successfully developed and largest gas field of low−medium rank coal in China. However, the production of coal fine has affected the continuous and stable drainage and efficient development of this area. The special response and mechanism of differential fluid action during the drainage process is one of the scientific issues that must be faced to solve this production problem. In view of this, the evolution laws of a reservoir’s macro−micro physical characteristics under different fluid conditions (fluid pressure, salinity) have been revealed, and the response mechanism of coal fine migration-induced reservoir damage has been elucidated through a nuclear magnetic resonance online displacement system. The results indicated that pores at different scales exhibited varying patterns with increasing displacement pressure. The proportion of the mesopore and transition pore is not affected by salinity and is positively correlate... [more]
Special Issue: Food Processing and Food Analysis: Principles, Techniques, and Applications
Jung-Feng Hsieh
January 5, 2024 (v1)
This Special Issue, entitled “Food Processing and Food Analysis: Principles, Techniques, and Applications”, explores perspectives and latest advances in the field of food science [...]
Preliminary Exploration of the Technology of Coal Reshaping and Replacement Mining of Abandoned Coal in Goafs
Li Li, Xiao Zhang, Bin Hu, Shun Lei
January 5, 2024 (v1)
Subject: Materials
Keywords: coal recycling, filling material, replacement mining
Recycling of coal resources left behind in goafs and the treatment and utilization of solid waste from mines are topical issues faced by the global coal mining industry at present. With the annual reduction of recoverable reserves of coal resources and the dependence on coal resources that are difficult to replace, the problems have become increasingly prominent, seriously limiting the development of coal resources and the implementation of environmental protection work. The mutual influence between the strength of filling materials and the size of loose coal in the CRRM process through numerical simulation experiments, laboratory rock mechanics experiments, and on-site large-scale similar simulation material experiments is explored. It is ultimately believed that selecting a filling material with a 20 cm particle size of loose coal and a 90% proportion of loose coal for 7 days can meet the requirements of the CRRM process, and this conclusion has been verified through on-site engineer... [more]
Characteristics and Effects of Laminae on a Cretaceous Reservoir in the Bozi−Dabei Area of the Tarim Basin, China
Wenhui Zhu, Tao Mo, Changchao Chen, Chunlei Hu, Cuili Wang, Chaoqun Shi, Lingling Shi, Pengzhen Li
January 5, 2024 (v1)
Keywords: Bozi–Dabei area, characteristics of laminae, Cretaceous reservoir, iron-stained argillaceous-enriched laminae, Kelasu structural belt, reservoir heterogeneity
Reservoir heterogeneity is an important factor in oil and gas exploration and development. It has guiding significance for favourable target optimization because it helps clarify the formation and development characteristics of laminae: thin, alternating layers of sediment deposited in a repeating pattern in Cretaceous sandstone reservoirs. Reservoir heterogeneity is higher when laminae are densely distributed. For example, laminae have a significant influence on reservoir properties in the Kelasu structural belt in the Bozi−Dabei area, Tarim Basin, China, where oil and gas wells have very low productivity. Hence, this study attempts to develop a classification scheme based on laminae to identify how they influence reservoir properties. Based on an analysis of cores, thin section and logging imaging data, laminae in this area can be classified into three types: magnetite-enriched, iron-stained argillaceous-enriched, and grain-size change. Results show that magnetite-enriched and iron-s... [more]
Simulation Analysis of the Effect of Slit/Slot Pintle Geometry on Atomization of Bipropellant Engine
Kun Cai, Zhen Zhang, Fengshan Wang, Yu Hu, Xudong Wang, Zhicheng Fang, Xiaofang Mao, Zhaopu Yao, Yusong Yu, Haiwang Li
January 5, 2024 (v1)
Keywords: bipropellant engine, impingement, pintle injector, Simulation, slit/slot, spray atomization
In order to optimize the slit/slot geometry design of a bipropellant pintle injector, the impinging spray development of a pintle injector was numerically investigated. The VOF (volume of fluid) and LES (large eddy simulation) methods were employed for an analysis to capture the gas−liquid interface by means of the AMR (adaptive mesh refinement) method. In those simulation cases, different flowrates, slot numbers, pintle diameters, slot thicknesses and slot shapes were compared for an analysis. In a comparison of visualization and quantification, a high flowrate and large pintle diameter were shown to be more positive features for improving the atomization quality and mixing effect. As for the slot parameters and shape, the spray development was mainly determined by the flow proportion between the slit jet and slot jet. The simulation results indicated that dominant slot jets cause a more dispersed spatial distribution, which is more conducive to the subsequent improvement of combustio... [more]
Theoretical Interpretation of pH and Salinity Effect on Oil-in-Water Emulsion Stability Based on Interfacial Chemistry and Implications for Produced Water Demulsification
Adango Miadonye, Mumuni Amadu
January 5, 2024 (v1)
Subject: Materials
Keywords: asphaltenes, degree of ionization, oil-in-water emulsion, produced water, salinity, surface charge density
The petroleum industry produces thousands of barrels of oilfield waters from the initial stage driven by primary production mechanisms to the tertiary stage. These produced waters contain measurable amounts of oil-in-water emulsions, the exact amounts being determined by the chemistry of the crude oil. To meet strict environmental regulations governing the disposal of such produced waters, demulsification to regulatory permissible levels is required. Within the electric double layer theory, coupled with the analytical solutions to the Poisson−Boltzmann Equation, continuum electrostatics approaches can be used to describe the stability and electrokinetic properties of emulsions. In the literature, much of the surface charge density and zeta potential relationship to emulsion stability has been confined to systems with less salinity. In this paper, we have exploited the theoretical foundations of the electric double layer theory to carry out theoretical evaluations of emulsion salinity b... [more]
Showing records 226 to 250 of 263. [First] Page: 6 7 8 9 10 11 Last