Search

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shandong Medical Journal is the property of Shandong Medical Health Newspapers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The load distribution problem of axisymmetric bolt can be reduced to a plane strain problem in cylindrical coordinate. The finite element models of fully grouted thread steel bolt was established by using ABAQUS to investigate the effects of thread steel bolt surface profile to load distribution of fully grouted bolt. By selecting a section of anchorage body for establishing its finite element model and numerical calculation， the time-space evolution of resin failure plane and the effect of rib face angle q， rib radial dimension coefficient d/D and rib spacing L on resin failure were analyzed emphatically. Experimental results show that the thread steel bolt load distributions are different from the rod bolt's markedly. The axial stress distribution of thread steel bolt along axis decreases more quickly than that of rod bolt， and the shear stress distribution of the resin and bolt interface along axis is zigzag. The q， d/D and L have strong influence on the failure strength and failure models of anchorage body. The space-time evolutions of anchorage body failure was summarized by jointly analyzing the thread steel bolt load distributions and failure models of anchorage body. [ABSTRACT FROM AUTHOR]

Intelligent ground control(IGC) at longwall working face is the significant and key part in wisdom coal mine and mining intelligentization, and is the crucial link from trial-and-error ground control to precise ground control as well as from static control to dynamic control. IGC is one of the important research fields in ground control. The connotation of IGC at longwall working face was defined, which is the ground control technology using modern information technology and artificial intelligent technology. The composition, perception and col-lection method and the utilization mode of coal mine data were analyzed. The coal mine data is used for big data analysis for evaluating ground control effectiveness and coal mine disaster characteristics, providing learning samples and analysis objects for artificial intelligence models, and used as the reference object for back analysis of dynamic numerical simulations and informationsource for data visualization and virtual reality of mining process. The pathways of dynamic analysis and state distinguish, real-time decision-making and control in IGC were proposed. The key scientific problems of IGC were clarified, that include the methodology and technology of perception and collection of coal mine data, the real-time rapid analysis of coal mine data, the intelligent model and algorithm of IGC, coal mine data visualization, the virtual reality for mining process, the principle and algorithm of rapid numerical simulation based on big data, and the algorithm integration and system construction for the whole process of IGC. Two specific IGC application cases on Support Vector Machine and Dynamic Numerical Simulation were introduced. [ABSTRACT FROM AUTHOR]

The massive emission of low concentration methane from the ventilation roadway results in the waste of resources and environmental pollution.For this serious situation,the vortex tower for methane enrichment with low concentration was designed and the segregation and non-segregation experiments were carried out as well as the comparison with numerical simulation results.The results reveal that the stable concentration of methane under segregation state in the vortex tower gradually increases from bottom to top (0.50%-0.70%),which demonstrates that the methane enrichment effect is significant in the weak vortex field under segregation state.However,the increase of the methane concentration under non-segregation state in the upper part of the vortex tower is not obvious (0.50%-0.55%).In both cases,the methane concentration at the bottom of the vortex firstly grows and then gradually reduces to stable state (less than 0.50%).The stability time of methane concentration in the upper (middle) part of the vortex tower under segregation state is longer than that under the non-segregation state while the stability time at the bottom of the vortex shows similar discipline.The stability time of the methane concentration is significantly affected by the speed of the blade in the weak vortex field while insensitive to the impact of the final gas concentration.Finally,the improved Richardson Numbers were used to discuss the strength and weak control of vortex field in terms of the speed of the mixing methane and the thickness of methane layer.The reasons for the methane enrichment in the prominent segregation state with low concentration whereas that on the weak condition in non-segregation state under the weak vortex field were revealed. [ABSTRACT FROM AUTHOR]

Fully-mechanized caving mining is the main technical way to achieve a high yield and high efficiency in coal production at extremely thick coal seam area in China. Intelligent fully-mechanized caving mining is one important development direction for fully-mechanized caving mining technology in the future. By analyzing the technology and problem of intelligent fully-mechanized caving mining in extremely thick coal seam with a ten-million-ton production level, this study focuses on the theme of safety, efficiency and intelligence, and the interaction between top coal body of extremely thick coal seam and overlying strata. Also, the study aims to understand the caving theory of extremely thick coal seam, realize intelligent caving mining in fully-mechanized caving face, reduce involving stone rate, and increase recovery rate. Therefore, the key scientific problems and technical ideas for solving the problems are proposed. To overcome the problems of the intelligent identification of coal gangue, the intelligent control of caving mining, and the intelligent coordination system of "mining-supporting-caving-transiting" in fully-mechanized caving mining, the study has condensed three scientific problems, i. e. , the crushing and caving mechanism of large scale top coal body, the method about the coordination control of intelligent mining and caving and the principle of caving control. The study has solved five key technological problems as follows:(1) the technology and decision technology of intelligent caving mining process of group collaborative in extremely thick coal seam;(2) the real-time monitoring technology of top coal thickness and caving coal quantity;(3) coal gangue detection technology which combined shock vibration with high spectra;(4) intelligent caving coal equipment and control technology of multimodal fusion;(5) intelligent coordination control technology of "mining-supporting-caving-transiting" system in a fully-mechanized caving mining face. This study overcomes the bottleneck of technology and equipment on intelligent fully-mechanized caving mining in extremely thick coal seam. As a result, the study has developed a coal gangue detection device, the control system and software of intelligent caving coal control, and solved the problems of mining and caving coordination, coal gangue detection and caving mining group. A demonstration project of intelligent fully mechanized caving mining with annual output of 15 million tons has been implemented. Finally, the intelligent fully-mechanized caving mining in extremely thick coal seam is realized, which provides a case and a reliable technical support for the future safe and efficient development of extremely thick coal seam. [ABSTRACT FROM AUTHOR]