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Use of the finite elements method for modelling the dynamic load impact on hydraulic leg equipped with gas accumulator

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Journal of Coal Science & Engineering(China) 2008年第2期14卷 171-175页

作者： GONDEK Horst MAZUREK Krzysztof SZWEDA Stanislaw VB-Technical University of Ostrava Ostrava 70833Czech Republic komag mining mechanization centre GliwicePoland mining and Geology Department Silesian University of TechnologyGliwicePoland

Procedures of preparation of numerical analysis,consisting in a simulation of cooperation of three different media: steel,liquid and gas undergoes dynamic load were *** of the initial static load of the mechanical system was *** using the *** products the following exemplary computer simulations were made: dynamic load impact on the hydraulic leg as well as effectiveness of the hydraulic leg protection against overload with help of gas accumulator.

关键词： finite elements dynamic load hydraulic leg equipped gas accumulator

Determination and(Re)Parametrization of Rational Developable Surfaces

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Journal of Systems Science & Complexity 2015年第6期28卷 1426-1439页

作者： SHEN Liyong PREZ-DíAZ Sonia School of Mathematical Sciences University of Chinese Academy of Sciences Key Laboratory of Mathematics mechanization Academy of Mathematics and Systems Science Chinese Academy of Sciences Key Laboratory of Big Data mining and Knowledge management Chinese Academy of Sciences Dpto de Física y Matemáticas Universidad de Alcalá

The developable surface is an important surface in computer aided design, geometric modeling and industrial manufactory. It is often given in the standard parametric form, but it can also be in the implicit form which is commonly used in algebraic geometry. Not all algebraic developable surfaces have rational parametrizations. In this paper, the authors focus on the rational developable surfaces. For a given algebraic surface, the authors first determine whether it is developable by geometric inspection, and then give a rational proper parametrization in the affrmative case. For a rational parametric surface, the authors also determine the developability and give a proper reparametrization for the developable surface.

关键词： Parametrization proper rational developable surface reparametrization

Study on the driving factors and regulation mode for coal production capacity

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Petroleum Science 2021年第5期18卷 1564-1577页

作者： Wen-Sheng Wang Jing-Jing Zhang School of Management China University of Mining and Technology-BeijingBeijing100083China

Coal production capacity regulation is a complex system involving economic growth,structural optimization,high-efficiency mining,and environmental *** on its driving factors,this paper forms four regulation modes representing different control orientations,establishes a system dynamics model,and predicts the regulation effects of single-factor and combined control *** result shows:(1) Except for the mechanization degree and recovery rate,the other nine individual production capacity control policies are all conducive to reducing coal production capacity and restraining the excessive growth of coal production capacity.(2) The effect of combined regulation mode on slowing down the growth of coal demand,regulating the excessive growth of coal production capacity and new capacity investment are obviously better than that of single policy.(3) The combined control modes have obvious differences in the suppression effect on coal production capacity:transformational development mode > technology-driven mode > structural optimization mode > efficiency improvement ***,in the process of achieving optimal regulation of coal production capacity,attention should be paid to the preferential use of transformational development and technology-driven *** the same time,the comprehensive use of regulation and control methods should also be considered to improve the regulation effect and the regulation efficiency of coal production capacity.

关键词： Coal production capacity Regulation mode Driving factors System dynamics model

Determination of coal mine mechanization using fuzzy logic

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mining Science and Technology 2009年第2期19卷 149-154页

作者： Ataei M Khalokakaei R Hossieni M Faculty of mining Petroleum and Geophysics EngineeringShahrood University of Technology

Two of the most important tasks in coal mines are to improve efficiency and to increase production besides keeping safety constantly in *** order to obtain these goals,mine mechanization is *** mechanization needs high levels of investment and should therefore be studied carefully before final decisions about mechanization are *** analysizing the potential for mechanization the following,rather imprecise,factors should be considered:seam inclination and thickness,geological disturbances,seam floor conditions,roof conditions,water at the working face and the extension of *** our study we have used fuzzy logic,membership functions and created fuzzy rule-based methods and to considered the ultimate objective:mechanization of *** a case study,the mechanization of the Takht coal seams in Iran was *** results show a high potential for mechanization in most of the Takht coal seams.

关键词： fuzzy set mechanization coal seams productivity safety

Research on software development of air temperature prediction in coal face

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Journal of Coal Science & Engineering(China) 2011年第3期17卷 294-297页

作者： QIN Yue-ping LIU Hong-bo WANG Ke LIU Jiang-yue State Key Laboratory of Coal Resources and Safe mining China University of Mining and Technology （Beijing） Beijing 100083 China

With ever-increasing depth of coal mine and the continuous improvement of mechanization, heat damage has become one of the major disasters in coal mine exploitation. Established the temperature prediction models suitable for different kinds of tunnels through analysis of the heat of shafts, roadways and working faces. The average annual air temperature prediction equation from the inlets of shafts to the working faces was derived. The formula was deduced using combine method of iteration and direct calculation. The method can improve the precision of air temperature prediction, so we could establish the whole pathway air temperature prediction model with high precision. Emphasizing on the effects of leakage air to air temperature of working face and using the ideology of the finite difference method and considering the differential equation of inlet and outlet at different stages, this method can significantly improve the accuracy of temperature prediction. Program development uses Visual Basic 6.0 Language, and the Origin software was used to fit the relevant data. The predicted results shows that the air temperature generally tends to rapidly increase in the air inlet, then changes slowly on working face, and finally increases sharply in air outlet in the condition of goaf air leakage. The condition is in general consistent with the air temperature change tendency of working face with U-type ventilation system. The software can provide reliable scientific basis for reasonable ventilation, cooling measures and management of coal mine thermal hazards.

关键词： finite difference method coal face air temperature prediction prediction methods

Application of fuzzy logic for determining of coal mine mechanization

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Journal of Coal Science & Engineering(China) 2012年第3期18卷 225-231页

作者： HOSSEINI S AA ATAEI M HOSSEINI S M AKHYANI M Department of mining Shahrood BranchIslamic Azad UniversityShahroodIran Faculty of mining Petroleum and GeophysicsShahrood University of TechnologyShahroodIran

The fundamental task of mining engineers is to produce more coal at a given level of labour input and material costs, for optimum quality and maximum efficiency. To achieve these goals, it is necessary to automate and mechanize mining operations. mechanization is an objective that can result in significant cost reduction and higher levels of profitability for underground mines. To analyze the potential of mechanization, some important factors such as seam inclination and thickness, geological disturbances, seam floor conditions and roof conditions should be considered. In this study we have used fuzzy logic, membership functions and created fuzzy rule-based methods and considered the ultimate objective： mechanization of mining. As a case study, the mechanization of the Tazare coal seams in Shahroud area of Iran was investigated. The results show a low potential for mechanization in most of the Tazare coal seams.

关键词： fuzzy logic mechanization coal seams productivity fuzzytech software

Design and test of 2ZYM-2 potted vegetable seedlings transplanting machine

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International Journal of Agricultural and Biological Engineering 2020年第1期13卷 101-110页

作者： Xin Jin Qun Cheng Bo Zhao Jiangtao Ji Mingyong Li College of Agricultural Equipment Engineering Henan University of Science and TechnologyLuoyang 471003China Collaborative Innovation Center of Machinery Equipment Advanced Manufacturing of Henan Province Luoyang 471003China Chinese Academy of Agricultural mechanization Sciences Beijing 100083China

In order to improve the efficiency and quality of transplanting vegetables in dry land,based on the seedling technology,transplanting effect and analysis of the planting process,a potted vegetable seedlings transplanting machine was *** mainly comprised rotary disc type feeding mechanism,five-bar duckbill type planting mechanism(simulated duckbill mechanism,disc cam,connecting rod,crank,fork,cable)and power transmission *** on the physical parameters of the seedlings and design requirements,it was determined that the diameter of the duckbill was D=90 mm,the opening and closing angle was 25°,and the taper angle was 17°.A test bench with adjustable parameters was built by analyzing the structure of the planting mechanism and the motion of the working *** digital speckle technique was used to optimize the parameters,so that the length of the crankshaftΙwas S1=100 mm,the length of the crankshaftΙΙwas S2=80 mm,the length of the connecting rodΙwas S3=140 mm,the length of the connecting rodΙΙwas S4=260 mm,the length of rod to connecting the rack was S6=314 mm,and the height of planting track was H=450 *** to the above parameters and the control requirements of the duckbill mechanism,the cam stroke was determined to be S=15 *** the initial phase difference between the two cams was 180°.The experiment was carried out with pepper seedlings as transplanting *** results showed that when the planting frequency was 50-70 plants/min,the seedling upright rate was 93%-91.1%,the planting depth qualified rate was 96%-92%.The leakage rate was 0-0.26%,the variation coefficient of plant spacing was 0.37%-0.67%,the injury rate was 0%,and the mechanical damage degree of the mining surface was 2.43-3.77 mm/*** machine can effectively improve the quality of transplanting,which can meet the production needs and design requirements of the mechanism.

关键词： seedling transplanting planting mechanism digital speckle parameter optimization test analysis

Maximal loads acting on legs of powered roof support unit in longwalls with bumping hazards

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Journal of Coal Science & Engineering(China) 2001年第2期7卷 1-15页

作者： Stanislaw Szweda(Silesian Technical University Faculty of mining and Geology mining mechanization Institute Gliwice, Poland) Silesian Technical University Faculty of mining and Geology mining Mec hanization Institute Gliwice Poland

In the article the results of measurements of the resultant force in the legs of a powered roof support unit, caused by a dynamic interaction of the rock mass, are discussed. The measurements have been taken in the longwalls mined with a roof fall, characterized by the highest degree of bumping hazard. It has been stated that the maximal force in the legs F m, recorded during a dynamic interaction of the rock mass, is proportional to the initial static force in the legs F st,p . Therefore a need for a careful selection of the initial load of the powered roof support, according to the local mining and geological conditions, results from such a statement. Setting the legs with the supporting load exceeding the indispensable value for keeping the direct roof solids in balance, deteriorating the operational parameters of a longwall system also has a disadvantageous influence on the value of the force in the legs and the rate of its increase, caused by a dynamic interaction of the rock mass. A correct selection of the initial load causes a decrease in the intensity of a dynamic interaction of the rock mass on powered roof supports, which also has an advantageous influence on their life. Simultaneously with the measurements of the resultant force in the legs, the vertical acceleration of the canopy was also recorded. It has enabled to prove that the external dynamic forces may act on the unit both from the roof as well as from the floor. The changes of the force in the legs caused by dynamic phenomena intrinsically created in the roof and changes of the force in the legs caused by blasting explosives in the roof of the working, have been analyzed separately. It has been stated that an increase in the loads of legs, caused by intrinsic phenomena is significantly higher than a force increase in the legs caused by blasting. It means that powered roof supports, to be operated in the workings, where the bumping hazard occurs, will also transmit the loads acting on a unit durin

关键词： longwall bumping hazard powered roof support unit

The new structure of fibre glass reinforced plastics bolt

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Journal of Coal Science & Engineering(China) 2003年第1期9卷 8-11页

作者：马念杰刘社育 School of Resource and Safety Engineering Beijing CampusChina University of Mining and Technology

The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed The new type structure of FRP bolt was designed Trial data indicate that, all kinds of capability target of this FRP bolt all achieve and exceed the country standard, substitute present metal bolt,wood bolt and bamboo bolt and other side bolt, it can gain magnitude technology and economy benefit FRP bolt mechanization product line produce efficiency is high, its throughput a day are 750 base, this can meet demand of hit small mining company

关键词： FRP bolt coal roadway support