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Articles 58291 - 58320 of 294413

Full-Text Articles in Physical Sciences and Mathematics

Multi-Objective Optimization Configuration Of Agv System Based On Response Surface And Nsga-Ii, Jianlin Fu, Guofu Ding, Jian Zhang, Haifan Jiang, Peipei Guo May 2022

Multi-Objective Optimization Configuration Of Agv System Based On Response Surface And Nsga-Ii, Jianlin Fu, Guofu Ding, Jian Zhang, Haifan Jiang, Peipei Guo

Journal of System Simulation

Abstract: Automated guided vehicle(AGV) system plays an important role in the production flexibility and efficiency in manufacturing systems. Due to the dynamic and stochastic characteristics of AGV system with many variables, its optimal configuration is relatively complex. A method combining system simulation, mathematical analysis and multi-objective optimization is proposed to optimize the configuration of AGV system. The discrete event simulation is used to simulate the operation of AGV system, the sensitivity analysis is used to separate design variables, the factorial experiments and response surface methods are used to build the fitting multi-objective optimization mathematical model, and the non-dominated sorting genetic …

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Study On The Scale Characteristics Of Permeability Of Tpms Porous Materials, Tong Wu, Qinghui Wang, Zhijia Xu May 2022

Study On The Scale Characteristics Of Permeability Of Tpms Porous Materials, Tong Wu, Qinghui Wang, Zhijia Xu

Journal of System Simulation

Abstract: Triply Periodic Minimal Surface (TPMS) has been widely used in the design of porous materials, however, there is insufficient research on the scale characteristics of permeability. Four commonly used TPMS units are chosen as the research object, based on the introduction of their mathematical models and porosity control methods, a numerical simulation model based on CFD (computational fluid dynamics) is established; TPMS units and cubic porous structures with different porosities are analyzed, the quantitative correlation between their scales and permeability is clarified, i.e., within the selected scale range, the permeability of various TPMS units and cubic porous structures is …

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Triangular Mesh Boolean Operation Method For Finite Element Analysis, Yufei Guo, Kang Zhao, Yongqing Hai May 2022

Triangular Mesh Boolean Operation Method For Finite Element Analysis, Yufei Guo, Kang Zhao, Yongqing Hai

Journal of System Simulation

Abstract: To shorten the cycle of finite element analysis (FEA), an adaptive triangular mesh Boolean operation method for finite element analysis is proposed. The ADT (alternating digital tree) data structure is applied to the intersection calculation of triangular meshes, which improves the efficiency of the intersection calculation of Boolean operations. A sphere packing algorithm and a node addition/deletion algorithm are used to remesh some remeshing regions, which ensures the efficiency of the method and the high-quality of remeshed meshes. An improved octree background grid is used to record and smooth the size field, which can generate size-adaptive meshes. The size …

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Cellular Automata Model Of Mixed Traffic Flow Composed Of Intelligent Connected Vehicles’ Platoon, Yangsheng Jiang, Sichen Wang, Kuan Gao, Meng Liu, Zhihong Yao May 2022

Cellular Automata Model Of Mixed Traffic Flow Composed Of Intelligent Connected Vehicles’ Platoon, Yangsheng Jiang, Sichen Wang, Kuan Gao, Meng Liu, Zhihong Yao

Journal of System Simulation

Abstract: To solve the existing cellular automata model of automatic-manual driving that does not consider the behavior of vehicle platoon, a cellular automata model of mixed traffic flow with the intelligent connected vehicles platoon is proposed, and the characteristics of mixed traffic flow are analyzed. The existing car-following behaviors in mixed traffic flow are analyzed. Based on the characteristics of the car-following behaviors, the cellular automata rules of human-driven vehicles (HDV), adaptive cruise control (ACC), and cooperative adaptive cruise control (CACC) are developed, respectively. Based on the numerical simulation experiments, the mixed traffic flow characteristics and congestion conditions are analyzed …

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Water Body Extraction From High Resolution Remote Sensing Images Based On Fused Visual Word Bags, Xin Wang, Mingjun Xu, Jian Xiao, Lizhong Xu May 2022

Water Body Extraction From High Resolution Remote Sensing Images Based On Fused Visual Word Bags, Xin Wang, Mingjun Xu, Jian Xiao, Lizhong Xu

Journal of System Simulation

Abstract: Aiming at the problem that water body extraction is easily influenced by shadow or light in high resolution remote sensing images, an improved algorithm based on fusion of visual word bags is proposed. Based on the deep analysis of the characteristics of remote sensing water body targets, a spectral feature extraction approach is designed. To enhance the description ability of water body targets, a novel visual word bag fusion model based on local binary pattern and spectral feature is constructed. Based on the proposed visual word bag fusion model, a water body target classifier is presented. …

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Study On Building Fire Evacuation Path Planning Based On Improved Ant Colony Algorithm, Jiangtao Liang, Huiqin Wang May 2022

Study On Building Fire Evacuation Path Planning Based On Improved Ant Colony Algorithm, Jiangtao Liang, Huiqin Wang

Journal of System Simulation

Abstract: Aiming at the problem of dynamic planning of evacuation paths in comprehensive building fires, with the shortest escape time required for evacuees as the goal, considering the impact of fire products and crowd density on the evacuation speed of personnel, an evacuation path planning model based on improved ant colony algorithm is constructed. A evacuation network data model composed of an obstacle vertex grid is established, the inspiration function of the ant colony algorithm and the deadlock processing strategy are improved, the explosion operator in the fireworks algorithm is introduced to optimize the ant path, and a comprehensive building …

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Teaching-Learning-Based Optimization Algorithm For Permutation Flowshop Scheduling, Qiwen Zhang, Bin Zhang May 2022

Teaching-Learning-Based Optimization Algorithm For Permutation Flowshop Scheduling, Qiwen Zhang, Bin Zhang

Journal of System Simulation

Abstract: A multi-classes teaching-learning-based optimization (MCTLBO) algorithm is proposed for the permutation flowshop scheduling problem (PFSP) by combining continuous algorithm with discrete strategy. An improved nawaz enscore ham (NEH) population initialization method based on permutation mutation is adopted, which takes into account the quality and diversity of initial solutions. In the teaching stage, discrete adaptive teaching with duplicate removal is introduced to avoid meaningless teaching processes. A new self-learning strategy based on Levy flight is added, and the self-learning in discrete stage is simulated by variable neighborhood search. Learner phase and class communication are combined to improve the efficiency of …

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Supply Chain Delivery Model And Simulation Based On Product Experience, Genshang Xing, Fang Lu, Shushan Li, Dingti Luo May 2022

Supply Chain Delivery Model And Simulation Based On Product Experience, Genshang Xing, Fang Lu, Shushan Li, Dingti Luo

Journal of System Simulation

Abstract: With the higher demand of consumers for delivery time of products purchased online, it is becoming more important for retailers to determine the delivery time of products based on product experience and market position. By constructing a supply chain delivery model under the three channel rights structure, the impact of product experience on the optimal delivery time, the retailer’s decision mode selection considering the delivery time and the supply chain profit after delivery are analyzed, and the correctness and reliability of the model are verified by numerical simulation. Research shows that the optimal product delivery time of retailers …

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Murals Super-Resolution Reconstruction With The Stable Enhanced Generative Adversarial Network, Jianfang Cao, Yiming Jia, Minmin Yan, Xiaodong Tian May 2022

Murals Super-Resolution Reconstruction With The Stable Enhanced Generative Adversarial Network, Jianfang Cao, Yiming Jia, Minmin Yan, Xiaodong Tian

Journal of System Simulation

Abstract: Aiming at the problems of low resolution and unclear texture details of ancient murals, which led to insufficient viewing of murals and low research value, a stable enhanced super-resolution generative adversarial networks (SESRGAN) reconstruction algorithm is proposed. Based on the generative adversarial network, the generative network uses dense residual blocks to extract mural features, and uses the visual geometry group (VGG) network as the basic framework of the discriminating network to determine the authenticity of the input mural, and introduces perception loss, content loss and penalty loss to jointly optimize the model. Experimental results show that, compared with other …

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Design Of Variable Stiffness Energy Storage Walking Assist Hip Exoskeleton And Simulation Of Assistance Effect, Bingshan Hu, Ke Cheng, Sheng Lu, Hongliu Yu May 2022

Design Of Variable Stiffness Energy Storage Walking Assist Hip Exoskeleton And Simulation Of Assistance Effect, Bingshan Hu, Ke Cheng, Sheng Lu, Hongliu Yu

Journal of System Simulation

Abstract: Passive energy storage walking assist exoskeleton makes full use of the human’s own energy, reducing energy consumption when walking. Aiming at the present passive energy storage walking assist exoskeleton adopts fixed stiffness joint, a passive variable stiffness energy storage walking assist hip exoskeleton is designed, on the base of joint energy flow characteristics in the process of people walking and the change of stiffness characteristics. The human-exoskeletons coupling model is established, and the optimal stiffness that minimizes the power consumption of the human body walking on a flat surface, as well as the total metabolism and the main thigh …

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Robot Path Planning Based On Bidirectional Aggregation Ant Colony Optimization, Xiangyang Deng, Limin Zhang, Wei Fang, Miao Tang May 2022

Robot Path Planning Based On Bidirectional Aggregation Ant Colony Optimization, Xiangyang Deng, Limin Zhang, Wei Fang, Miao Tang

Journal of System Simulation

Abstract: Path planning is a key theoretical issue of the autonomous mobile robot technology. This paper utilizes an improved grid method to establish environment model, which involves a new priori advantage azimuth structure that includes two parts of the primary dominant grid cell and the subprime grid cell. It improves the pheromone mark ant colony optimization algorithm by putting forward a novel pheromone update strategy based on secondary path cognitive method, which is called bidirectional guidance strategies. It repeats an alternation of the starting point and the target point in each new round of iteration. The experimental results show that …

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Research On Parametric Modeling And Deformation Method Of Human Muscle, Na Ni, Kunjin He, Xincheng Zhu, Zhengming Chen May 2022

Research On Parametric Modeling And Deformation Method Of Human Muscle, Na Ni, Kunjin He, Xincheng Zhu, Zhengming Chen

Journal of System Simulation

Abstract: Due to the volume preserving constraint of human muscle in the deformation process, and the lack of three-dimensional multi-angle representation of muscle motion, a parametric modeling and deformation method of human muscle is proposed. Based on MRI (magnetic resonance imaging) data, the external contour line is extracted from the slice image generated by MRI data to construct a three-dimensional muscle model; muscle features are defined hierarchically, and the mapping relationship between semantic parameters is established to realize the volume preserving deformation of muscle; by establishing a vector-valued dynamic fourth-order differential equation, the feature curve dynamically simulates the process …

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State Prediction Of Poverty Alleviation Objects Based On Hmm And Multidimensional Data, Jun He, Sunyan Hong, Yifang Zhou, Shikai Shen, Muquan Zou May 2022

State Prediction Of Poverty Alleviation Objects Based On Hmm And Multidimensional Data, Jun He, Sunyan Hong, Yifang Zhou, Shikai Shen, Muquan Zou

Journal of System Simulation

Abstract: In order to solve the problems of inaccurate prediction of poverty, poverty reduction and poverty returen, and the difficulty in identifying the key factors affecting the state transition, 8 key features and 22 observed states are extracted from the poverty reduction basic data and multi-industry data. The relationship between observed state and implied state is constructed, and the hidden markov model (HMM) of poverty alleviation is established. Data of a deep poverty county for three consecutive years are used as samples for parameter training, test experiment and result verification. The results show that the method has a strong …

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Simulation Of Navigation Process Based On Nonlinear Observer, Zhiwei Wang, Jizong Hu, Fengjie Wang, Jie Huang May 2022

Simulation Of Navigation Process Based On Nonlinear Observer, Zhiwei Wang, Jizong Hu, Fengjie Wang, Jie Huang

Journal of System Simulation

Abstract: In order to solve the problem that the scope of using thetraditional observers is limited by assumptions, in the process of establishing the observer, a parameter projection relationship is designed and added to the observer to keep it under the condition of not being constrained by the assumptions. It is semi-globally stable, and the estimation process is more direct, which makes the parameter estimation process under nonlinear conditions converge faster. The simulation results show that the computational complexity of the nonlinear observer is reduced by nearly 80% compared with the multiplicative extended Kalman filter. The experimental results show that …

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A Visual Analytics Of Urban Traffic Events Using Social Media Data, Xiangping Wu, Lijun Ping, Dongshi Xu May 2022

A Visual Analytics Of Urban Traffic Events Using Social Media Data, Xiangping Wu, Lijun Ping, Dongshi Xu

Journal of System Simulation

Abstract: Traffic text data in social media can supplement traffic flow information, for which a visual analysis method for traffic events is proposed. A text processing model is designed to process the social media data and extract the description information of traffic event. The vector representation of road node attributes is learned based on graph embedding algorithm, and a road similarity model is estbalished. A prediction model of the traffic event is built based on the road similarity and the kernel density model. An interactive visual analysis system is designed to carry out visual analysis. Though traffic …

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Research On Visual Inspection Algorithm Of Crimping Appearance Defects For Wiring Harness Terminals, Bingan Yuan, Mingen Zhong, Jingxin Ni May 2022

Research On Visual Inspection Algorithm Of Crimping Appearance Defects For Wiring Harness Terminals, Bingan Yuan, Mingen Zhong, Jingxin Ni

Journal of System Simulation

Abstract: Aiming at the low efficiency and high missing rate of wiring harness terminals, an image detection method based on machine vision is proposed. The characteristic parameters of five typical defects in three main parts of wiring harness terminals are analyzed and defined. Tthe algorithms of extracting positioning datum, segmenting inspected-parts adaptively, extracting the defect features and calculating the characteristic parameters are designed respectively, and the defects criterions are given. The experimental results show that the algorithms are suitable for single defect and multi-class defects, both the miss detection rate and the false positiveness rate are low. The accuracy and …

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Phased Array Radar Doa Estimation Simulation System Designed With Interactive Control, Fan Yu, Dongqi Luo, Binqiang Si, Jihong Zhu May 2022

Phased Array Radar Doa Estimation Simulation System Designed With Interactive Control, Fan Yu, Dongqi Luo, Binqiang Si, Jihong Zhu

Journal of System Simulation

Abstract: For the problem of simulation, evaluation and verification of phased array radar the direction of arrival (DOA) estimation of phased array radar, the modeling and evaluation of phased array radar DOA estimation is discussed. A real-time simulation system based on interactive control is designed. The simulation system can be used to model and simulate the interactive target & environment, phased array and target detection efficiency evaluation model. The signal generation, free space propagation, echo signal acquisition, signal processing and other processes can be simulated during the detection of real-time flying target, and the effect of DOA estimation can be …

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Research On Immersive Virtual Reality Interactive System For Flow Visualization, Shijian Xu, Dan Zhao, Chengyu Su, Fupan Wang, Xiaorong Zhang, Fang Wang, Yadong Wu May 2022

Research On Immersive Virtual Reality Interactive System For Flow Visualization, Shijian Xu, Dan Zhao, Chengyu Su, Fupan Wang, Xiaorong Zhang, Fang Wang, Yadong Wu

Journal of System Simulation

Abstract: Aiming at the problem of low interaction efficiency due to the lack of depth information in the current desktop flow visualization application based on the two-dimensional display interaction environment, virtual reality technology is introduced to design and implement an immersive flow visualization system with diversified interaction methods. Based on the gaze and gesture interaction technology, the system designs and implements gesture-based navigation methods and three-dimensional interactive widgets based on user requirements, as well as immersive interactive panels based on user gaze and gestures. We designed and implemented an immersive interactive management method based on visual scenes and a visual …

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Specific Properties And Combustion Characteristics Of Natural Coke From Adjacent Areas Of Jiangsu, Shandong, Henan And Anhui Provinces, Qin Yunhu, Wang Shuangmei, Zhu Shifei, Wu Guoqiang, Quan Jutao, Mao Lixin May 2022

Specific Properties And Combustion Characteristics Of Natural Coke From Adjacent Areas Of Jiangsu, Shandong, Henan And Anhui Provinces, Qin Yunhu, Wang Shuangmei, Zhu Shifei, Wu Guoqiang, Quan Jutao, Mao Lixin

Coal Geology & Exploration

It is particularly important to improve resource utilization efficiency against the background of carbon peak and carbon neutrality, but the natural coke has not been paid enough attention for a long time. The natural coke is abundant in China and is often found in the mining of coal mines in neighboring areas of Shandong, Henan and Anhui provinces. Due to the intrusion of magmatic rock, the original coal seam is baked and transformed into natural coke. In this study, samples of natural coke from various areas were collected to study its macroscopic and microscopic characteristics. The industrial analysis, geochemical parameters, …

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Nanopore Structure And Surface Roughness In Brittle Tectonically Deformed Coals Explored By Atomic Force Microscopy, Zhang Ningyuan, Yao Suping May 2022

Nanopore Structure And Surface Roughness In Brittle Tectonically Deformed Coals Explored By Atomic Force Microscopy, Zhang Ningyuan, Yao Suping

Coal Geology & Exploration

The pore structure of coal is the key to coalbed methane (CBM) exploration and exploitation, and coal mining safety. Compared to primary coals, tectonically deformed coals (TDCs) have stronger heterogeneity and are of great importance in coal reservoir study. Here, the pore structure and surface roughness of brittle TDCs were obtained with atomic force microscopy (AFM) and NanoScope Analysis and Gwyddion software. The results show that tectonic deformation generally promotes the pore development in brittle TDCs, but the extent of tectonic impact varies greatly among different brittle TDCs. As a result, two stages in brittle TDCs were identified: weak brittle …

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Evaluation Method And Application Of Fracturing Effect Based On Dynamic Permeability Change Of Coal Reservoir Hydraulic Fracturing, Shan Tuo, Sun Changyan, Wang Qian, Xie Xiangjun, Fan Yigang May 2022

Evaluation Method And Application Of Fracturing Effect Based On Dynamic Permeability Change Of Coal Reservoir Hydraulic Fracturing, Shan Tuo, Sun Changyan, Wang Qian, Xie Xiangjun, Fan Yigang

Coal Geology & Exploration

The fracturing construction curve is considered to be an important basis for reflecting the fracturing effect, while the dynamic change of reservoir permeability in the fracturing stage can more intuitively reflect the effect of fracture formation. In this paper, a quantitative evaluation method for reservoir dynamic permeability in fracturing stage was established based on the principle of well testing. Then, the method was applied to evaluate the fracturing effect of two coalbed methane (CBM) wells in a block in southern Junggar Basin, and the dynamic permeability curve of reservoir during fracturing stage is obtained. Meanwhile, the G-function method was …

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Efficient Treatment Technology Of Incrementally Open Water Gushing Channel Under Dynamic Water Conditions, Pu Zhiguo, Ding Xiang, Li Zhe, Ji Zhuochen, Yan Xin, He Xiaolang, Ma Jianguo May 2022

Efficient Treatment Technology Of Incrementally Open Water Gushing Channel Under Dynamic Water Conditions, Pu Zhiguo, Ding Xiang, Li Zhe, Ji Zhuochen, Yan Xin, He Xiaolang, Ma Jianguo

Coal Geology & Exploration

In Yushen mining area of Shaanxi Province, a blasting expansion fissure on the eastern side of the Xiwan Open-pit Coal Mine communicates the water-bearing body of burnt rock outside the pit, and an incrementally open water gushing channel with a length greater than 65 m is formed. The water volume gushing from burnt rock stabilizes at about 400 m3/h and the flow velocity is as high as 0.36 m/s, resulting in a series of problems in ecology, environmental protection, economy and safety. To block the water gushing channel and solve the problem as soon as possible, a quick …

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Optimization Calculation Of The Width Of Waterproof Coal Pillars In Fault Zones Based On Spatial Relationship Between Coal Strata And Fault, Wu Bin, Xie Daolei, Han Jing, Chen Qiang, Zhang Huide May 2022

Optimization Calculation Of The Width Of Waterproof Coal Pillars In Fault Zones Based On Spatial Relationship Between Coal Strata And Fault, Wu Bin, Xie Daolei, Han Jing, Chen Qiang, Zhang Huide

Coal Geology & Exploration

The appropriate setting width of the waterproof coal pillars is an important measure to prevent water inrush hazard during near fault mining. The working face 123up01(south) of Jining No.3 Coal Mine in Shandong Province is adjacent to F8 fault in the west. The fall of F8 fault is large, which may be conducted with the Ordovician limestone aquifer at the bottom. To ensure the safe mining in the working face, it is necessary to calculate the size of waterproof coal pillars of fault F8. In view of the actual occurrence of coal strata, the spatial relationship between fault …

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Numerical Simulation Of Azimuth Electromagnetic Wave Response Of Complex Geological Model Of Horizontal Hole In Coal Mines, Zhang Yi, Kang Zhengming, Feng Hong, Han Xue, Chen Gang May 2022

Numerical Simulation Of Azimuth Electromagnetic Wave Response Of Complex Geological Model Of Horizontal Hole In Coal Mines, Zhang Yi, Kang Zhengming, Feng Hong, Han Xue, Chen Gang

Coal Geology & Exploration

The advance and accurate identification of the coal-rock interface is one of the key technologies to realize automatic tunneling and intellectualization of coal mines. Azimuth electromagnetic wave tool has a large detection range and can distinguish the lithologic interface and interface orientation. It has been successfully applied in oilfield logging, but there are few researches on the coal mine measurement environment. In order to study the detection performance of azimuth electromagnetic wave logging in the complex 3D model of coal mines, the finite element numerical simulation method is used to investigate the influence of the drilling fluid in the borehole …

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3d Forward Modeling Of Dc Resistivity Method Based On Finite Element With Mixed Grid, Wang Xinyu, Wang Cheng, Mao Yurong, Yan Liangjun, Zhou Lei, Gao Wenlong May 2022

3d Forward Modeling Of Dc Resistivity Method Based On Finite Element With Mixed Grid, Wang Xinyu, Wang Cheng, Mao Yurong, Yan Liangjun, Zhou Lei, Gao Wenlong

Coal Geology & Exploration

The DC resistivity method is widely used in the mineral resources exploration and geological survey industries because of its high efficiency and low cost, such as non-ferrous metals and coal fields. However, in the process of borehole–to–surface and surface–to–borehole resistivity method exploration, the influence of borehole factors (borehole fluid resistivity and borehole diameter) on the apparent resistivity response in different exploration modes is unclear, and whether it will affect the interpretation of apparent resistivity data is an issue worth exploring. Therefore, we proposed a mixed grid finite element method to realize the 3D forward modeling of DC resistivity. Then we …

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Preliminary Investigation Of Uranium Resource Evaluation Method Based On Natural Gamma Logging Data：A Case Study Of The Pengyang Uranium Deposit In Ordos Basin, Yu Reng’An, Sun Dapeng, Zhou Xiaoxi, Deng Fan, Si Qinghong, Hu Yongxing May 2022

Preliminary Investigation Of Uranium Resource Evaluation Method Based On Natural Gamma Logging Data：A Case Study Of The Pengyang Uranium Deposit In Ordos Basin, Yu Reng’An, Sun Dapeng, Zhou Xiaoxi, Deng Fan, Si Qinghong, Hu Yongxing

Coal Geology & Exploration

“Coal and uranium exploration” and “oil and uranium exploration” are current research hotspots. Using logging data of coal and oilfield drilling to further evaluate uranium resources remains a difficult problem. Taking the Pengyang uranium deposit in the Ordos Basin as an example, this article explores the method of evaluating uranium resources based on natural gamma logging data. According to the remarkable features of the natural gamma anomaly response in the sandstone-type uranium reservoirs in the study area, the natural gamma logging regression model of the quantitative gamma logging value of the uranium deposit in the Pengyang area was studied by …

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Study And Application On Multi Branch Point Sampling Drilling Technology Of Coal Seam Floor Borehole, Chu Zhiwei, Long Weicheng, Jia Bingyi, Liu Fei May 2022

Study And Application On Multi Branch Point Sampling Drilling Technology Of Coal Seam Floor Borehole, Chu Zhiwei, Long Weicheng, Jia Bingyi, Liu Fei

Coal Geology & Exploration

According to the technical requirements of long-distance gas parameter measurement, gas extraction borehole design guidance, and extraction evaluation for broken soft coal seam, the multi branch point sampling drilling method of coal seam floor borehole was proposedand its sampling drilling process was formulated on the basis of analyzing existing problems of sampling and drilling technology. Furthermore, the key drilling technologies such as accurate drilling trajectory control and “mechanical + hydraulic” efficient slag removal were developed. The equipment of drilling and sealed sampling were introduced. The application test was carried out in a coal mine in Suzhou, Anhui Province, in which …

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Simplified Internal Variable Gradient Model For Zonal Disintegration Of Rocks In Circular Underground Tunnels, He Ziguang, Zhao Fasuo, Chen Haoxiang, Wu Bo, Zhou Jingjing May 2022

Simplified Internal Variable Gradient Model For Zonal Disintegration Of Rocks In Circular Underground Tunnels, He Ziguang, Zhao Fasuo, Chen Haoxiang, Wu Bo, Zhou Jingjing

Coal Geology & Exploration

As one of the typical nonlinear phenomena of deep level surrounding rock masses, zonal disintegration has captured many attentions of geotechnical engineers in the past years. On the basis of the internal variable theory, the closed-form analytical solutions to stress, strain and displacement fields near circular tunnels are obtained. The gradient-dependent solutions are compared with the results of the classical elasticity theory, and the effects of microstructures on the stresses and deformation fields are investigated as well. It is noted that the stress and deformation fields derived from the gradient model show remarkable quasi-periodicity and fluctuation, which is consistent with …

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Powder Discharge Characteristics Of Pneumatic Double Pipe Directional Drilling In Broken Soft Coal Seams And Its Application, Nie Chao, Wang Yi, Yao Yafeng, Hong Jianjun May 2022

Powder Discharge Characteristics Of Pneumatic Double Pipe Directional Drilling In Broken Soft Coal Seams And Its Application, Nie Chao, Wang Yi, Yao Yafeng, Hong Jianjun

Coal Geology & Exploration

To study the influence of casing, casing bit size and casing rotational speed on pulverized coal discharge in double pipe directional drilling technology, three kinds of casing and casing bits in different sizes are designed respectively against the background of pneumatic double pipe directional drilling in the broken soft coal seam, the changes of the discharge rate and outlet velocity of pulverized coal under different combinations are analyzed, and the influence law of different casing rotational speeds on the suspension rate and conveying trajectory of pulverized coal are obtained. The numerical simulation results show that the ø120/96 mm casing with …

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Searches For Gravitational Waves From Known Pulsars At Two Harmonics In The Second And Third Ligo-Virgo Observing Runs, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, M. G. Benjamin, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang May 2022

Searches For Gravitational Waves From Known Pulsars At Two Harmonics In The Second And Third Ligo-Virgo Observing Runs, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, M. G. Benjamin, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the l = m = 2 mass quadrupole mode with a frequency at only twice the pulsar rotation frequency (single harmonic) and the l = 2, m = 1, 2 modes with a frequency of both once and twice the rotation frequency (dual harmonic). No evidence of GWs was found, so we present 95% credible upper limits on the strain amplitudes …

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