检索结果-南通市图书馆

Applying Acoustic Emission Technique in Rock Mechanics

在线全文

学校读者我要写书评

暂无评论

Applying Acoustic Emission Technique in Rock Mechanics

第二届全国压电和声波理论及器件技术研讨会

作者： Xingdong Zhao,Yuanhui Li (school of resources & civil engineering,northeastern university,shenyang,110006,P.R.china)

Acoustic emission(AE),which is produced by the micro-cracks occurrence or growth,is an ubiguitous phenomenon associated with brittle fracture in many materials,such as *** technique can monitor the microfractures development in the rock sample continuously and in-real-time,which is better than other methods.A Simplex and Geiger location algorithm allows AE event location from first arrival times to be determined by AE sensors,which was applied to study the crack initiation and propagation process,also to analyze the crack spatial evolution mode with stress changing during the total loading *** this paper,introducing AE location method and reverse evolvation principle;applying different location algorithm to study AE location event in different rock;analyzing the location error of AE *** on above study,experimental study AE location event of signal crack,double cracks and normal rock sample,and study AE space evolvement mode of crack initiation,crack propagation and coalescence during rock failure process;analyzing relation to stress(strain),loading time and AE events,which is contributed to study failure character of rock instability process;by AE experiment,analyzing inner and outer factor influence AE event location;By AE event location technique, studying systematically different rock samples(granite,red granite,marble,black marble and sandstone), loading mode(uniaxial loading,cyclic loading and three point bending loading),loading route,Brazil splitting testing and size effect *** analyzing the relation to AE activity and rock failure process, disclosuring inner relation to AE activity and rock failure and instability,which is very significant to study the mechanism of rock failure.

关键词： Acoustic emission Rock failure Uniaxial loading Crack propagation process

Effects of Temperature and Atmosphere on Pellets Reduction Swelling Index

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 7-12,19页

作者： WANG Zhao-cai, CHU Man-sheng, LIU Zheng-gen, CHEN Shuang-yin, XUE Xiang-xin (school of Materials and Metallurgy, northeastern university, shenyang 110819, Liaoning, china) school of Materials and Metallurgy Northeastern University Shenyang 110819 Liaoning China

After taking into account the conditions of the domestic iron resources and the non-coking coal resources, the process of coal gasification-shaft furnace is an effective way to develop direct reduction iron in china. The following tasks are very critical to choose suitable process of shaft furnace and gasification, including the production of oxidized pellets with excellent comprehensive properties as well as the study of the reaction behavior and mechanism of swelling. The results showed that the oxidized pellets of using domestic magnetic iron concentrate as raw materials have favorable comprehensive properties, including higher mechanical strength both before and after reduction, faster reduction rate and lower reduction swelling index (RSI). All of these properties can meet the shaft furnace yielding requirement. When the temperature was below 1 223 K, the pellets′ RSI was lower than 20%. With increasing of the content of H2 in atmosphere, the pellets reaction rate accelerated, crushing strength enhanced and RSI decreased. The RSI dropped to 10.26% at 1 323 K in 100% H2 atmosphere, and it is up to 39.88% in 100% CO atmosphere. The iron grains mainly presented in platelike when pellets were reduced by H2, however, in CO atmosphere the iron grains were precipitated in flocculent. The whisker shape of iron grains and heating effects of reduction reaction are the major factors leading to the poor pellets strength and increase of RSI. Appropriately controlling the temperature and increasing the ratio of H2 to CO in atmosphere are good for dropping the RSI.

关键词： oxidized pellet shaft furnace direct reduction reduction swelling

Experiments and sensitivity analyses for heat transfer in a meter-scale regularly fractured granite model with water flow

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang university-Science A(Applied Physics & engineering) 2012年第12期13卷 958-968页

作者： Wei LU1,2,Yan-yong XIANG1 (1school of civil engineering,Beijing Jiaotong university,Beijing 100044,china) (2State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,china Institute of Water resources and Hydropower Research,Beijing 100038,china) 1. school of civil engineering Beijing Jiaotong University Beijing 100044 China 2. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing 100038 China

Experiments of saturated water flow and heat transfer were conducted for a meter-scale model of regularly fractured granite. The fractured rock model （height 1502.5 ram, width 904 mm, and thickness 300 mm）, embedded with two vertical and two horizontal fractures of pre-set apertures, was constructed using 18 pieces of intact granite. The granite was taken from a site currently being investigated for a high-level nuclear waste repository in china. The experiments involved different heat source temperatures and vertical water fluxes in the embedded fractures either open or filled with sand. A finite difference scheme and computer code for calculation of water flow and heat transfer in regularly fractured rocks was developed, verified against both the experimental data and calculations from the TOUGH2 code, and employed for parametric sensitivity analyses. The experiments revealed that, among other things, the temperature distribution was influenced by water flow in the fractures, especially the water flow in the vertical fracture adjacent to the heat source, and that the heat conduction between the neighboring rock blocks in the model with sand-filled fractures was enhanced by the sand, with larger range of influence of the heat source and longer time for approaching asymptotic steady-state than those of the model with open fractures. The temperatures from the experiments were in general slightly smaller than those from the numerical calculations, probably due to the fact that a certain amount of outward heat transfer at the model perimeter was unavoidable in the experiments. The parametric sensitivity analyses indicated that the tem- perature distribution was highly sensitive to water flow in the fractures, and the water temperature in the vertical fracture adjacent to the heat source was rather insensitive to water flow in other fractures.

关键词： Fractured granite Water flow Heat transfer Physical modeling Numerical calculation Sensitivity analysis

General Ethernet Interface for Embedded System Based on wwwImplementation of a RTL-8019

在线全文

学校读者我要写书评

暂无评论

General Ethernet Interface for Embedded System Based on wwwI...

第一届国际测量仪器与测试自动化学术会议

作者： Fu Chong Jiang Huiyan Li Hui Zhu Weiyong ( school of Information Science and engineering. northeastern university shenyang 110004 china) ( Computing Center northeastern university shenyang 110004 china) ( school of Information Science and engineering. shenyang university of Technology. shenyang 110023 china)

＜正＞This paper proposes a design and implementation scheme of a general Ethernet interface for embedded system based on ARM7 and RTL-8019 NIC （network interface controller） hardware platform. The design aims at the characteristics that the embedded system only has limited resources and reduced any unnecessary operation process. The logic structure, operation principle and DMA controller data sending and receiving principles of RTL-8019 NIC and Ethernet frame encapsulation process are explained in detail. The registers programming process for realizing NIC initialization, operation of local/remote DMA controller and Ethernet frame sending and receiving are also discussed.

关键词： NIC embedded system Ethernet.

MODELING UNCONFINED SEEPAGE FLOW USING THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2010年第4期22卷 554-561页

作者： JIANG Qing-hui DENG Shu-shen ZHOU Chuang-bing LU Wen-bo school of civil engineering Wuhan University Wuhan 430072 China State Key Laboratory of Water resources and Hydropower engineering Science Wuhan University Wuhan 430072 China

Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this *** constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the global simultaneous equations for unconfined seepage analysis are derived in *** algorithm of locating the free surface and the formula for seepage forces are also ***-dimensional manifold method employs the tetrahedral mathematical meshes to cover the whole material *** the iterative process for locating the free surface,the manifold method can achieve an accurate seepage analysis of the saturated domain below the free surface with mathematical meshes *** the shape of manifold elements can be arbitrary,the disadvantage of changing the permeability of transitional elements cut by the free surface in the conventional Finite Element Method（FEM） is removed,and the accuracy of locating the free surface can be ***,the seepage force acting on the transitional elements can be accurately calculated by the simplex *** results for a typical example demonstrate the validity of the proposed method.

关键词： three-dimensional seepage numerical manifold method free surface mathematical mesh manifold element

Numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第4期53卷 1098-1113页

作者： JU Yang1,2,WANG HuiJie1,YANG YongMing1,HU QinAng3 & PENG RuiDong1 1 State Key Laboratory of Coal resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,china university of Mining and Technology,Beijing 100083,china 2 Department of Mechanical and Manufacturing engineering,university of Calgary,Calgary,Alberta,T2N 1N4,Canada 3 school of Environment and civil engineering,College of engineering,Oklahoma State university,Stillwater,OK 74078,USA 1. State Key Laboratory of Coal resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary Calgary Alberta T2N 1N4 Canada3. School of Environment and Civil Engineering College of Engineering Oklahoma State University Stillwater OK 74078 USA

The pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of CT scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were *** 3D finite element models of the rock media with varied porosities were established based on the CT image processing of the physical models and the MIMICS software *** failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation *** dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were *** is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element *** applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.The deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around *** stresses lead to microplasticity,while tensile stresses result in cracking of the *** and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold *** simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical *** present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster mechanism

关键词： porous media three-dimensional finite element model rock media stress wave failure mechanism energy dissipation

Research on Cake-removing Performance of Dust in Filter Medium

在线全文

学校读者我要写书评

暂无评论

Research on Cake-removing Performance of Dust in Filter Medi...

2006（沈阳）国际安全科学与技术学术研讨会

作者： XU Xiaohu XU Kaili ZHOU Jiahong SUN Xi College of resources and civil engineering northeastern university shenyang 110004 china Liaodong College Dandong 118001 china

＜正＞Ratio of cake - removing of dust in filter media is an important indicator to measure cleaning efficiency of filter media. The current method used to measure ratio of cake - removing of dust in filter media is method of resistance. In recent years, because of the widespread use of membrane filter media, many shortcomings of method of resistance used to measure ratio of cake - removing of dust in filter media are presented. In this paper, in order to fill this gap, method of mass was applied to measure ratio of cake - removing of dust in filter media. An effective testing program was developed. And a testing device was designed and installed, in which eight dif- ferent filter media were used to test ratio of cake - removing of dust in filter media in use of method of mass and method of resistance respectively. According to the results, some important laws of ratio of cake - removing of dust in filter media are yielded, which are useful references for the bag house precipitator colleagues.

关键词： filter media cake - removing performance of dust method of mass method of resistance

Application of Set Pair Analysis in Safety Assessment

在线全文

cnki会议

学校读者我要写书评

暂无评论

Application of Set Pair Analysis in Safety Assessment

2006（沈阳）国际安全科学与技术学术研讨会

作者： ZHOU Jiahong GENG Liyan XU Kaili ZHENG Xin College of resources & civil engineering northeastern university shenyang 110004 china Liaodong College Dandong 118001 china

＜正＞This paper applies SPA in the safety assessment, adopt the pluralistic connection number model to appraise the current safety situation of three workshops in a certain company in a city, and compare the safety states of different workshops of the same rank. Through the analysis on set pair situation, predict the development trend of the safety state of every department. This method can give a quantitative description of the operating of the system, the mathematics formula is simple, and it doesn’t need relevant function, not a large amount of data, it is convenient to calculate, and thus it offers a new way for safety assessment. Difference degrees i, prove the transformation degree among the identical, discrepancy and contrary item of system, reflect the safety management levels of enterprises, it is "barometer" and " direction sign" of enterprise’s safety management.

关键词： set pair analysis safety assessment connection degree pluralistic connection number model set pair situation

NEURAL NETWORK ASSESSMENT OF ROCKBURST RISKS FOR DEEP GOLD MINES IN SOUTH AFRICA

在线全文

cnki会议

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1998年第2期8卷 160-166页

作者： Feng XiatingCollege of resources and civil engineering,northeastern university, shenyang 110006, P. R. chinaS. WebberCSIR Mining Technology, Johannesburg, South AfricaM. U. OzbayDepartment of Mining engineering,university of the Witwatersr

ＮＥＵＲＡＬＮＥＴＷＯＲＫＡＳＳＥＳＳＭＥＮＴＯＦＲＯＣＫＢＵＲＳＴＲＩＳＫＳＦＯＲＤＥＥＰＧＯＬＤＭＩＮＥＳＩＮＳＯＵＴＨＡＦＲＩＣＡ①ＦｅｎｇＸｉａｔｉｎｇＣｏｌｅｇｅｏｆＲｅｓｏｕｒｃｅｓａｎｄＣｉｖｉｌＥｎｇ... 详细信息

ＮＥＵＲＡＬＮＥＴＷＯＲＫＡＳＳＥＳＳＭＥＮＴＯＦＲＯＣＫＢＵＲＳＴＲＩＳＫＳＦＯＲＤＥＥＰＧＯＬＤＭＩＮＥＳＩＮＳＯＵＴＨＡＦＲＩＣＡ①ＦｅｎｇＸｉａｔｉｎｇＣｏｌｅｇｅｏｆＲｅｓｏｕｒｃｅｓａｎｄＣｉｖｉｌＥｎｇｉｎｅｒｉｎｇ，Ｎｏｒｔｈｅａｓｔ...

关键词： neural network rockburst risk South Africa