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Showing records 133 to 157 of 358. [First] Page: 1 3 4 5 6 7 8 9 10 11 Last
Classification and Evaluation of Tight Sandstone Reservoirs Based on MK-SVM
Xuefei Lu, Xin Xing, Kelai Hu, Bin Zhou
January 12, 2024 (v1)
Keywords: high-pressure mercury compression, lasso dimensionality reduction, MK-SVM model, reservoir classification, tight sandstone reservoirs
It is difficult to determine the main microscopic factors controlling reservoir quality due to the strong microscopic heterogeneity of tight sandstone reservoirs, which also makes it difficult to distinguish dominant reservoirs. At the same time, there are fewer experimental samples available, and data collected from relevant research are thus worth paying attention to. In this study, based on the experimental results of high-pressure mercury injection of 25 rock samples from Chang 6 reservoir in the Wuqi area, Lasso dimensionality reduction was used to reduce the dimensionality of 14 characteristic parameters to 6, which characterize the microscopic pore structure, while a combination of different kernel functions was used to construct the multi-kernel function of the multi-kernel model to be determined. A multi-kernel support vector machine (MK-SVM) model was established for unsupervised learning of microscopic pore structure characteristic parameters that affect reservoir quality. B... [more]
Active Steering Controller for Driven Independently Rotating Wheelset Vehicles Based on Deep Reinforcement Learning
Zhenggang Lu, Juyao Wei, Zehan Wang
January 12, 2024 (v1)
Keywords: active steering, Ape-X DDPG algorithm, deep reinforcement learning, independently rotating wheelsets
This paper proposes an active steering controller for Driven Independently Rotating Wheelset (DIRW) vehicles based on deep reinforcement learning (DRL). For the two-axle railway vehicles equipped with Independently Rotating Wheelsets (IRWs), each wheel connected to a wheel-side motor, the Ape-X DDPG controller, an enhanced version of the Deep Deterministic Policy Gradient (DDPG) algorithm, is adopted. Incorporating Distributed Prioritized Experience Replay (DPER), Ape-X DDPG trains neural network function approximators to obtain a data-driven DIRW active steering controller. This controller is utilized to control the input torque of each wheel, aiming to improve the steering capability of IRWs. Simulation results indicate that compared to the existing model-based H∞ control algorithm and data-driven DDPG control algorithm, the Ape-X DDPG active steering controller demonstrates better curving steering performance and centering ability in straight tracks across different running conditio... [more]
Evaluation of the Effect of Betulin and Its Alkynyl Derivatives on the Profile of Changes in Gene Expression of the Inflammatory Process of Colorectal Adenocarcinoma Cells (HT-29 Cell Line)
Agnieszka Lubczyńska, Ewa Bębenek, Agnieszka Garncarczyk, Dominika Wcisło-Dziadecka
January 12, 2024 (v1)
Subject: Biosystems
Keywords: betulin, colorectal cancer, inflammation
Betulin is a lupane-type pentacyclic triterpene. It is characterized by a range of biological properties, including anti-cancer and anti-inflammatory activities. It is also an origin compound for obtaining derivatives with higher biological activity and better bioavailability. Chronic inflammation stimulates the formation of a pro-cancer microenvironment, promoting tumor growth, cell migration, and neoangiogenesis. Many factors, immune system cells, and cytokines and chemokines released by them are involved in this process. Therefore, it has been suggested that the optimal target for anti-cancer drugs in this disease could be substances showing anti-inflammatory activity. The aim of the study was to indicate the direction of changes in the expression of genes related to the inflammatory state in colorectal cancer cells promoted by betulin and its selected alkynyl derivatives. Cytotoxicity assessment was carried out using a sulforhodamine B (SRB) test, whereas lipophilicity was determin... [more]
Evaluation of Hydrogen Addition on Combustion and Emission Characteristics of Dual-Fuel Diesel Engines with Different Compression Ratios
Su Wang, Youchang Li, Junshuai Lv, Zhonghang Liu, Sheng Gao, Jingyi Hu, Jian Zhang, Weihuang Zhong, Ziheng Zhao
January 12, 2024 (v1)
Keywords: combustion characteristics, compression ratio, dual-fuel engine, emission characteristics, hydrogen energy share
In this paper, a computational fluid dynamics (CFD) model was established and verified on the basis of experimental results, and then the effect of hydrogenation addition on combustion and emission characteristics of a diesel−hydrogen dual-fuel engine fueled with hydrogenation addition (0%, 5%, and 10%) under different hydrogenation energy shares (HESs) and compression ratios (CRs) were investigated using CONVERGE3.0 software. And, this work assumed that the hydrogen and air were premixed uniformly. The correctness of the simulation model was verified by experimental data. The values of HES are in the range of 0%, 5%, 10%, and 15%. And, the values of CR are in the range of 14, 16, 18, and 20. The results of this study showed that the addition of hydrogen to diesel fuel has a significant effect on the combustion characteristics and the emission characteristics of diesel engines. When the HES was 15%, the in-cylinder pressure increased by 10.54%. The in-cylinder temperature increased by... [more]
Rice Water—More a Source of Nutrition Elements or Toxic Arsenic? Multi-Element Analysis of Home-Made (Natural) Rice Water and Commercialized Rice-Based Products Using (HG)-ICP OES
Maja Welna, Anna Szymczycha-Madeja, Pawel Pohl
January 12, 2024 (v1)
Keywords: arsenic, multi-element analysis, nutritional value, rice water, rice-based cosmetics
Although rice is a well-known source of nutrients, it unfortunately accumulates As the most compared to other cereal plants. Due to the growing interest in rice-based cosmetics, the aim of the work was the multi-element analysis of various home-made (natural) rice waters and commercialized ready-to-use rice-based cosmetics for skin/hair. The total concentrations of Al, As Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in raw rice and rice products were determined using inductively coupled optical emission spectrometry (ICP OES) after wet sample decomposition in the presence of concentrated HNO3. In the case of As, the hydride generation (HG) technique was used as a sample introduction system to the ICP OES instrument. Five different procedures, including washing/rinsing, soaking, boiling, and fermentation steps, and three rice types, i.e., white, brow, and jasmine, were used for this purpose. The effects of the water temperature, the contact time of rice grains with water, and the type of... [more]
Transdermal Patches Containing Opioids in the Treatment of Patients with Chronic Pain
Iolanda De Marco
January 12, 2024 (v1)
Subject: Biosystems
Keywords: buprenorphine, fentanyl, reservoir and matrix systems, transdermal patches
Transdermal delivery is a non-invasive route, used as an alternative to the oral route, to administer drugs through the skin surface. One of the fields in which they are particularly used is that of pain therapy. In this treatment, transdermal patches, particularly those containing opioids, are used to complement or replace orally administered drugs. First-generation patches are constituted by reservoir systems, where the drug is dissolved in a solvent and gelled with a polymer. In contrast, the active principle is incorporated into the polymer adhesive in more recent matrix patches. In this review, the main papers related to the production and employment of transdermal patches containing the two most used opioids, i.e., fentanyl and buprenorphine, have been critically analyzed. From the analysis of the literature, it is possible to deduce that the type of drug and the amount of drug present in the patch must be chosen not according to the origin of the pain but to the age of the patie... [more]
A Perspective on the Prospect of Pickering Emulsion in Reservoir Conformance Control with Insight into the Influential Parameters and Characterization Techniques
Muhammad Mohsin Yousufi, Iskandar bin Dzulkarnain, Mysara Eissa Mohyaldinn Elhaj, Shehzad Ahmed
January 12, 2024 (v1)
Subject: Materials
Keywords: conformance control, emulsion, Pickering emulsion
In reservoir conformance control, polymer gels and foams are majorly used; however, they have drawbacks such as inducing formation damage, having weaker shear resistance, requiring a higher pumping rate, and limited penetration depth. Emulsions are a potential alternative that can address these issues, but they are not widely used. Current surfactant-based emulsions require high emulsifier concentrations for stability and often rely on multiple additives to address various factors, which makes the surfactant synthesis and utilization of emulsions quite challenging. However, Pickering emulsions, which utilize solid particles for emulsion stabilization, have emerged as a promising solution for reservoir conformance control. Compared to conventional polymer gels and foams, Pickering emulsions offer superior shear resistance, deeper penetration, and reduced formation damage. This review provides an overview of recent developments in the utilization of Pickering emulsions for conformance co... [more]
Comparative Study of Rhodamine B Treatment: Assessing of Efficiency Processes and Ecotoxicity of By-Products
Thomas Chadelaud, Hicham Zeghioud, Alonso Reynoso de la Garza, Omar Fuerte, Adriana Benítez-Rico, Messika Revel, Tomás E. Chávez-Miyauchi, Hayet Djelal
January 12, 2024 (v1)
Subject: Materials
Keywords: eco-toxicity assessment, photocatalysis, Rhodamine B degradation, Saccharomyces cerevisiae, TiO2-Ce
In this work, a comparative study between two processes was performed—biodegradation and photocatalysis, as an advanced oxidation process—to discover which one is more efficient to degrade Rhodamine B, a synthetic dye widely used in the textile and food industries. The advantage of this study is that it correlates treatment efficiency with the ecotoxicity of the by-products resulting from the treatments. Since the COVID-19 pandemic, it has been difficult to use activated sludge because of the risk factor of COVID-19 infection. Therefore, biodegradation tests were conducted with the yeast Saccharomyces cerevisiae in this study. For the photocatalysis assays, TiO2 doped with 5 per cent Cerium was used as a catalyst under UV light irradiation. S. cerevisiae cannot reduce RhB by biodegradation. However, a 13 per cent biosorption was observed with an uptake capacity of 4.2 mg g−1 dry matter of S. cerevisiae cultivated in the presence of 5 mg L−1 of RhB after 150 min. At a 5 mg L−1 of RhB co... [more]
Research on Downhole Throttling Characteristics of Gas Wells Based on Multi-Field and Multi-Phase
Jie Zheng, Jiahui Li, Yihua Dou, Zhihao Hu, Xu Yang, Yarong Zhang
January 12, 2024 (v1)
Keywords: downhole throttling characteristics, multi-field and multi-phase coupling, temperature and pressure field model
The formation of natural gas hydrates seriously affects the production efficiency of gas wells. Obtaining the correct temperature and pressure profile along the wellbore of gas wells is a prerequisite for accurately predicting the location of hydrate formation and using downhole throttling technology. According to the numerical iterative transfer law of wellbore microelement state parameters, a multi-field and multi-phase coupling method is proposed. Based on the analysis of typical temperature and pressure models, considering the gas well velocity field and density field, a gas well multi-phase correction coefficient is introduced. Based on the judgment method of multi-phase flow pattern, the friction gradient equation of multi-phase flow is obtained, and the respective theoretical prediction equations are created for the temperature field, pressure field, density field, and velocity field. Thereby, a wellbore temperature and pressure field model with multi-field and multi-phase coupl... [more]
Design and Analysis of a Novel Air Bubble Curtain for Mixing and Aeration in Process Vessels
Omar Chaalal, Chandra Mouli R. Madhuranthakam, Husain Al Hashimi, Marouane Chaalal, Weam S. K. Abudaqqa
January 12, 2024 (v1)
Keywords: bubble curtain, Mixing, pilot-scale studies, process vessels, residence time distribution
This article focuses on designing and analyzing a new method for mixing in process vessels. We propose using an air bubble curtain to accomplish the desired mixing. The air bubble curtain used in this study is made of an empty pipe with several holes through which air is pumped, which in turn produces a swarm of bubbles that causes pseudo-turbulent mixing in the tank filled with a liquid solution. A uniform distribution of bubbles within the tank was assured by maintaining a see-saw movement of the air bubble curtain. Mixing inside the tank was quantified by measuring the salt concentration in a laboratory model tank (30 cm × 30 cm × 30 cm) and a pilot-scale tank (200 cm × 100 cm × 100 cm). The optimal flow rates of air and the mixing time in both tanks that can achieve complete mixing were obtained from the experimental results. The proposed air bubble curtain can be of potential use in wastewater treatment, biotechnology, and aquaculture where turbulent mixing is required with minimu... [more]
Multi-Scale Fractal Characteristics of the Pore System in Low-Permeability Conglomerates from the Junggar Basin
Jiayu Zheng, Weichao Tian, Yang Gao, Zhigang Wen, Yunpeng Fan, Heting Gao, Shuangfang Lu, Xiaoyin Zheng
January 12, 2024 (v1)
Subject: Materials
Keywords: fractal characteristics, Junggar Basin, low-permeability conglomerates, NMR, pore system
The pore structure and its complexity play a critical role in fluid migration and recovery efficiency. Multiple pore types, broad pore size distribution (PSD), and extremely irregular pore morphology hinder the comprehensive investigation of pore systems and their complexity in low-permeability conglomerates. In this study, the multi-scale pore system and fractal characteristics of the Permian Lower Wuerhe Formation and Triassic Baikouquan Formation conglomerates from the Junggar Basin were investigated, combining physical property analysis, casting thin sections, scanning electron microscopy, and Nuclear magnetic resonance (NMR). The results show that the pore system of conglomerates consists of residual intergranular pores (RIPs), dissolution pores (DPs), clay-related pores (CRPs), and microfractures. Three types of PSD were identified according to the shape of the T2 spectrum. Based on the fractal characteristics derived from NMR data, pore systems in conglomerates were divided into... [more]
Recovering Polyphenols in Aqueous Solutions from Olive Mill Wastewater and Olive Leaf for Biological Applications
Adrián Hernández-Fernández, Yolanda Garrido, Eduardo Iniesta-López, Antonia Pérez de los Ríos, Joaquín Quesada-Medina, Francisco José Hernández-Fernández
January 12, 2024 (v1)
Keywords: circular economy, hydroxytyrosol, oleuropein, olive leaf, olive mill wastewater, polyphenols
Olive leaf and olive mill wastewater are wastes which are produced in olive industry and can be used to obtain value-added products such as polyphenols. In this work, extracts of polyphenols from olive mill wastewater and olive leaf in an aqueous medium are obtained and their composition in polyphenols were determined and compared with those obtained using the conventional extract agent (methanol−water). The antioxidant capacity of the aqueous extracts of olive mill wastewater and olive leaf were also analysed. It was observed that the olive mill wastewater extracted in water provides a similar content of phenolic compounds in the final extract compared to extraction with methanol−water, with the main polyphenols being hydrotyrosol and tyrosol (20.1 and 6.61 mg gdw−1). In the case of leaf extraction, the methanol-free extract (recovery in water after extraction with methanol−water) had a lower total phenol content compared to the methanolic extract, with the main polyphenol being oleur... [more]
Fast Prediction of the Temperature Field Surrounding a Hot Oil Pipe Using the POD-BP Model
Feng Yan, Kaituo Jiao, Chaofei Nie, Dongxu Han, Qifu Li, Yujie Chen
January 12, 2024 (v1)
Keywords: BP neural network, hot oil pipe, POD prediction, temperature field
The heat transfer assessment of a buried hot oil pipe is essential for the economical and safe transportation of the pipeline, where the basis is to determine the temperature field surrounding the pipe quickly. This work proposes a novel method to efficiently predict the temperature field surrounding a hot oil pipe, which combines the proper orthogonal decomposition (POD) method and the backpropagation (BP) neural network, named the POD-BP model. Specifically, the BP neural network is used to establish the mapping relationship between spectrum coefficients and the preset parameters of the sample. Compared with the classical POD reduced-order model, the POD-BP model avoids solving the system of reduced-order governing equations with spectrum coefficients as variables, thus improving the prediction speed. Another advantage is that it is easy to implement and does not require tremendous mathematical derivation of reduced-order governing equations. The POD-BP model is then used to predict... [more]
Design and Research of a Field Bus Control System Laboratory for Metal Mining, Beneficiation and Metallurgy
Siyuan Wang, Jiugang Lei, Shan Hu, Guxiu Tang, Zhen Chen, Weiwei Yang, Yufeng Liu, Guofan Zhang
January 12, 2024 (v1)
Keywords: communication network, DCS, fieldbus, industrial process control, laboratory construction, mining and metallurgy, nonferrous metal
Fieldbus control systems play a pivotal role in industries such as mining, beneficiation, and metallurgy, facilitating precise process control. However, diverse process conditions and applications often lead to challenges during system implementation. The prevalence of process control projects underscores the need for dedicated control system laboratories to address these problems. Our research delves into the complexities of process control systems, focusing on mainstream brands such as Siemens, Rockwell, and Emerson, involving analysis of network architectures, software, and hardware configurations. Through rigorous testing of real equipment systems, we uncover prevalent issues in practical control system applications. These findings guide the resolution of technical challenges faced in project control, concurrently enhancing the design and debugging prowess of engineering professionals. We also anticipate the trajectory of intelligent manufacturing, embracing collaborative manufactu... [more]
Phosphorus Recovery from Wastewater Aiming Fertilizer Production: Struvite Precipitation Optimization Using a Sequential Plackett−Burman and Doehlert Design
Paulo Victor Campos, Rômulo Simões Angélica, Lênio José Guerreiro de Faria, Simone Patrícia Aranha Da Paz
January 12, 2024 (v1)
Keywords: combined responses, DOE, phase identification, thermochemical analysis
The precipitation of struvite from wastewater is a potential alternative for the recovery of nutrients, especially phosphorus, which is an essential macronutrient for agriculture but can be harmful to the environment when improperly disposed of in water bodies. In addition, struvite has elements of great added value for agricultural activity (P, N, and Mg) and is, therefore, considered a sustainable alternative fertilizer. In its formation process, several intervening physicochemical factors may be responsible for the production yield levels. Optimization processes can help to define and direct the factors that truly matter for precipitation. In this context, a sequential design of experiments (DOE) methodology was applied to select and optimize the main struvite precipitation factors in wastewater. Initially, a screening was performed with eight factors with the aid of Plackett−Burman design, and the factors with a real influence on the process were identified. Then, a Doehlert design... [more]
Optimizing the Control of the Hydraulic Driving System for the Power Shift Gearbox of a Cotton Picker Based on Dual Working Conditions
Yuangang Lin, Jingan Feng, Pengda Zhao, Xiangdong Ni, Huajun Chen, Haoyun Ye, Yongqiang Zhao, Wenlong Pan, Bao Song
January 12, 2024 (v1)
Keywords: automatic control, BP neural network control, cotton picker, power shifting, Statechart logic control
In response to the issues of slow dynamic response, uneven shifting, and strong jolting during the starting and shifting operations of the cotton picker, we established a model for automatic power shifting control. We proposed optimization strategies using the Statechart logic control method and BP neural network control method. Different control effects were analyzed concerning pressure, flow rate, motor speed, vehicle speed, impact degree, and slip-grinding work. The results showed that the Statechart logic control method increased the response time of the flow rate by 46.67% during the starting process, with a good linear characteristic during the variation. It reduced the impact during starting and shifting by 38.57% and 67%, and the sliding friction power during starting and shifting by 51.95% and 33.33% respectively. The BP neural network control method reduced the pressure overshoot during starting and shifting by 25% and 30.77%, respectively, demonstrating better robustness. Th... [more]
Special Issue “Multiphase Flows and Particle Technology”
Xizhong Chen, Li Ge Wang, Liping Li
January 12, 2024 (v1)
Research into multiphase flow and particle technology is closely related and holds significant importance in various fields of engineering and scientific applications [...]
Enhancing Electric Discharge Machining Performance by Selecting Electrode Design and Geometrical Parameters for Square, Triangular, and Hexagonal Profiled Holes
Madiha Rafaqat, Nadeem Ahmad Mufti, Muhammad Qaiser Saleem, Naveed Ahmed, Ateekh Ur Rehman, Sadaf Zahoor, Muhammad Asad Ali
January 12, 2024 (v1)
Subject: Materials
Keywords: electric discharge machining, land thickness, material removal rate, relief angle, tool design, tool wear rate
Manufacturing of dies, molds, and their allied components requires the machining of holes with different profiles. Electric discharge machining (EDM) die-sinking is a crucial process used in the dies and molds manufacturing industry. By nature, EDM die-sinking is a relatively slow process in terms of material removal rate (MRR) and there are high amounts of tool material loss in terms of tool wear rate (TWR) which directly influence dimensional accuracies and surface roughness (SR). Therefore, the process is continuously evolving to address these limitations. The present research is aligned in this direction such as to bring improvements in MRR, TWR, and SR through modifications to the conventional electrode design and its geometrical parameters. Traditional designs of EDM electrodes have a uniform cross-section through the tool’s entire length and have only one geometrical parameter, i.e., the tool’s cross-section. To improve the EDM performance, traditional designs are completely mod... [more]
Design of Continuous Kneading System for Active Anode Material Fabrication Using Retrofitted Assembly of Co-Rotating Screw Extruder
Gang-Ho Lee, Hyenoseok Yi, Hye-Ryeong Cho, Yu-Jin Kim, Sei-Min Park, Seong-Jin Yoon, Dong-Jin Seo, Kyeongseok Oh, Jeong-Mi Yeon, Sun-Yong Choi, Seong-Ho Yoon, Joo-Il Park
January 12, 2024 (v1)
Subject: Materials
Keywords: anode material, artificial graphite, kneading process, lithium ion battery, twin-screw extruder
As the demand for artificial graphite for lithium-ion battery (LIB) anode materials is on the rise, technologies for optimizing the manufacturing processes and reducing the production costs of artificial graphite are crucial. At the same time, globally, regulations on the generation of harmful volatile substances during the artificial graphite production process are also becoming increasingly stringent. In this study, we focused on a continuous kneading process that minimizes the emission of volatile substances during the manufacturing of artificial graphite. To this end, a carbonized material was first prepared from a mixture of needle coke and binder pitch and processed at 3200 °C using two types of co-rotating twin-screw extruder-based continuous kneading equipment to ultimately obtain artificial graphite. The physical properties of the carbonized as well as graphitized materials were analyzed, which revealed the superior performance of the LIB anode material, namely a discharge cap... [more]
Construction of a Multifunctional PCM@Catalyst Composite and Its Application in the Fluid Catalytic Cracking Process
Guoqing An, Zhixiang Cheng, Ying Ouyang, Siqi Liu, Hongyi Gao
January 12, 2024 (v1)
Subject: Materials
Keywords: Al-Si alloy, catalyst, catalytic cracking, multifunctional composite, phase change microcapsules
Fluid catalytic cracking (FCC) is one of the most important processes in gasoline/diesel oil production, but the strong endothermic effect accompanied by this reaction often results in the deactivation of the catalyst. In this paper, a novel multifunctional phase change material (PCM)@Catalyst composite was designed and constructed, in which the PCM could be used to store waste heat and regulate the temperature for enhancing the catalytic efficiency of the FCC catalyst. Firstly, a core/shell Al-12wt%Si@Al2O3 was prepared via subsequent vapor treatment and high-temperature calcination of an Al-12wt%Si sphere. The Al species in the Al-12wt%Si served as the source of metal ions and was transformed in situ into a well-defined Al2O3 shell, which greatly improved the thermal stability and prevented the leaking of the Al-12wt% Si core in the high-temperature situation. The PCMs@Catalyst composite was then fabricated by casting the mixed powder of Al-12wt%Si@Al2O3 and Y zeolite into a granulat... [more]
Photo-Programmable Processes in Bithiophene−Azobenzene Monolayers on Gold Probed via Simulations
Vladyslav Savchenko, Moufdi Hadjab, Alexander S. Pavlov, Olga Guskova
January 12, 2024 (v1)
Keywords: azobenzene, charge transfer, chemisorbed monolayer, conjugated oligomer, molecular modeling, molecular switch, organic electronics, photoisomerization
In this study, we investigate the structural changes, electronic properties, and charge redistribution within azo-bithiophene (Azo-BT)-chemisorbed monolayers under different light stimuli using the density functional theory and molecular dynamics simulations. We consider two types of switches, Azo-BT and BT-Azo, with different arrangements of the Azo and BT blocks counting from the anchor thiol group. The chemisorbed monolayers of pure cis- and trans-isomers with a surface concentration of approximately 2.7 molecules per nm2 are modeled on a gold surface using the classical all-atom molecular dynamics. Our results reveal a significant shrinkage of the BT-Azo layer under UV illumination, whereas the thicknesses of the Azo-BT layer remain comparable for both isomers. This difference in behavior is attributed to the ordering of the trans-molecules in the layers, which is more pronounced for Azo-BT, leading to a narrow distribution of the inclination angle to the gold surface. Conversely,... [more]
Numerical Simulation Study on Vibration Reduction Effect of Flexible Cutting-Tooth Unit
Haitao Ren, Jingwei Xu, Xin Jia, Sheng Zhou, Chunxiao Zhou, Yingxin Yang, Qi Zhan
January 12, 2024 (v1)
Keywords: drilling speed, flexible cutting, impact dynamic load, PDC bit, rock breaking mechanism
Under the conditions of drilling in gravel-bearing and heterogeneous stratas, the movement and force of the PDC bit during drilling are highly unstable. Irregular impact loads often cause fatigue failures such as tooth fracture, tooth breakage and delamination of the composite sheet. Dynamic impact load is the main cause of fatigue failure of cutting-tooth, which seriously affects the rock-breaking performance of PDC bits. This paper proposes a flexible cutting tooth unit consisting of a central tooth, an elastic element, and a base. The technical concept of flexible-cutting rock breaking is to reduce the impact load amplitude suffered during the cutting process to a certain threshold range by setting elastic elements or reducing the support stiffness of the cutting tooth, so as to inhibit the expansion of micro defects caused by the impact dynamic load of cutting teeth and prolong the service life of drill bits. The finite-element models of flexible cutting teeth for rock cutting were... [more]
Study on the Migration and Transformation of Nitrogen in Mine Water under the Action of Water−Coal Interactions
Binbin Jiang, Ze Zhao, Zhiguo Cao, Deqian Liu, Jiawei Tang, Haiqin Zhang, Yuan Liu, Dingcheng Liang
January 12, 2024 (v1)
Keywords: coal mine underground reservoir, migration transformation, nitrogen, water–coal interaction
The coal pillar dam of underground reservoirs and residual coal in goaves have a direct impact on the quality of mine water. In this paper, the coal pillar dam of an underground reservoir and residual coal in the goaf and mine water in the Daliuta coal mine are used as research objects. The adsorption mechanism of residual coal with respect to NO3− in mine water was analyzed by carrying out adsorption experiments. The composition and variation of organic matter in mine water at different times were simulated using three-dimensional fluorescence spectrum analysis. The influence of residual coal and microorganisms in underground reservoirs on the change in NO3− contents in mine water was explored. Moreover, the mechanism of NO3− changes in the water body was clarified. The results showed that the concentration of NO3− in the water first decreased and then increased, showing a downward trend as a whole. The adsorption of NO3− by residual coal led to a decrease in its concentration, which... [more]
Boosting CO2 Uptake from Waste Concrete Powder Using Artificial Intelligence and the Marine Predators Algorithm
Hegazy Rezk, Ali Alahmer, Rania M. Ghoniem, Samer As’ad
January 12, 2024 (v1)
Keywords: ANFIS modeling, CO2 uptake, marine predators algorithm, mineral carbonation, waste concrete powder
Waste concrete powder (WCP) is emerging as a potential method of adoption for CO2 sequestration due to its ability to chemically react with carbon dioxide and trap it within its structure. This study explores the application of artificial intelligence (AI) and the Marine Predators Algorithm (MPA) to maximize the absorption of CO2 from waste concrete powder generated by recycling plants for building and demolition debris. Initially, a model is developed to assess CO2 uptake according to carbonation time (CT) and water-to-solid ratio (WSR), utilizing the adaptive neuro-fuzzy inference system (ANFIS) modeling approach. Subsequently, the MPA is employed to estimate the optimal values for CT and WSR, thereby maximizing CO2 uptake. A significant improvement in modeling accuracy is evident when the ANOVA method is replaced with ANFIS, leading to a substantial increase of approximately 19% in the coefficient of determination (R-squared) from 0.84, obtained through ANOVA, to an impressive 0.999... [more]
Simulation and Experimental Study on Vibrating Screen-Type Grain-Recovery Device with Upper Centrifugal Fan
Yanjun Li, Yanguang Gong, Yongtao Yu, Fuxiang Xie
January 12, 2024 (v1)
Keywords: CFD–EDEM, grain recovery, orthogonal experiment, virtual simulation
To solve the problem of grain loss caused by nibbling during the working process of the maize ear and stem harvesting machine, a vibrating screen-type grain-recovery device with an upper centrifugal fan was designed. The device mainly consists of a centrifugal fan and vibrating screen. The work process of the grain-recovery device is theoretically analyzed, and it is clarified that the turning of the bracts is the key to separating the bracts from the grains, and the design criteria of the vibrating screen are obtained. The CFD−EDEM coupled single-factor simulation experiment was carried out on the size of the vibrating screen sieve hole and the number of draft bars, and the motion posture of the bracts was simulated. Based on the previous CFD−EDEM coupled simulation study, the orthogonal experiment was carried out on the fan speed, vibration screen drive-shaft speed, and operation speed of the grain-recovery device. The orthogonal experimental results show that, when the fan speed is... [more]
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