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Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of 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 Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of 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 upper frozen layer is one of the main factors affecting the blasting effect of the plateau open-pit bench. To clarify the fracture law of the upper frozen layer of the open-pit bench under the blasting load in the cold area of the plateau, this paper uses the particle flow code method to simulate the fracture process of the natural single frozen layer and the artificial composite double-frozen layer under the action of single and double rows of blast holes respectively. The frozen layer s speed, impact pressure, and fragmentation characteristics were analyzed. The results show that the frozen layer undergoes the failure process of cracking-local uplift-macro fracture. For the artificial composite frozen layer,the thickness increases due to the increase of the gravel soil in the upper part, which weakens the overall uplift trend of the frozen layer and leads to increased fragmentation. The impact pressure on the frozen layer in the middle of the double-row blast hole first reaches the peak, but the peak value on the frozen layer near the free surface is higher. The fracture problem of single and double frozen layers under blasting load can be simplified as the structural fracture mechanics problem under impact pressure. The large block rate of double-frozen-layer bench is 4% to 6% higher than that of single-frozen-layer. It is suggested that in the blasting of plateau open-pit mines, the area that needs special treatment should be preliminarily determined by the thickness of the frozen layer, and the large block rate should be reduced by adjusting the delay time to improve the efficiency of shovel-to-digging. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering 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 Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office 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.)

In order to study the effect of charge decoupling coefficients on the extent of granite blasting damage, a particle flow code (PFC) blasting simulation method with mixed "dynamic" and "quasi-static" loads is proposed based on the joint action of blast shock wave and detonation gas, and then the numerical simulation of granite blasting process under six decoupling coefficients was carried out. The results show that the extent of granite blasting damage increases and then decreases as the decoupling coefficients increases; the number of blasting induced cracks under coupled charge is 9 367, which increases to 24 975 when the decoupling coefficient is 1.2, and then decreases to 292 when the decoupling coefficient is 2.0. Comparing to the damage pattern under coupled charge, the extension distance of blasting induced crack is obviously shorter when the decoupling coefficient is 1.4, which indicates that the quasi-static pressure of blast gas plays an important role in crack extension. According to the number of blasting cracks, the prediction model of rock blasting damage under different decoupling coefficients greater than or equal to 1.2 was established, and the fitting degree reaches 0.980 8. The prediction model presented in this paper is of certain reference significance for practical blasting design. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office 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 Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering 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 Chongqing University of Technology (Natural Science) is the property of Chongqing University of 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 Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu 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 South China University of Technology (Natural Science Edition) is the property of South China University of 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 Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology 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.)

This paper aims to describe an industrial application of the Discrete Element Method (DEM). The DEM is often employed in granular and solid-fluid mixture systems. The DEM is a Lagrangian approach, where individual particles are simulated based on Newton's second law of motion. In my group, novel models are developed to apply the DEM in industrial powder systems, i.e., coarse grain model of the DEM for efficient calculation of large-scale powder systems and combination of signed distance functions and immersed boundary method for efficient creation of arbitrary shaped wall boundary. These models are shown to be crucial for a numerical simulation of an industrial powder system. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Heilongjiang University of Science & Technology is the property of Journal of Heilongjiang University of Science & Technology 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 Clean Coal Technology is the property of Clean Coal 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 dense medium cyclone is widely used in coal separation process. The experimental study on internal flow field and particle motion characteristics of dense medium cyclone is difficult and time-consuming with high cost, due to the complicated separation process. With the development of numerical calculation technology, the numerical simulation method was widely used to study the multiphase flow field inside the cyclone. In this paper, the computational fluid dynamics (CFD) and discrete analysis (DEM) coupling techniques were used to numerically simulate the separation process of dense medium cyclones, which provided a new way to optimize the structural parameters and operating parameters of dense medium cyclones. The Fluent software was used to study the velocity field, density field, pressure gradient field and viscosity field of the internal suspension of the cyclone. The EDEM software was used to study the coal particle movement behavior and the evaluation of separation efficiency during the cyclone separation process. The results showed that the pressure distribution and the pressure gradient of suspension were basically symmetrical, and the pressures at the overflow and underflow outlet were the lowest. The pressure gradient was formed along the radial direction, the difference gradually increased, and the largest pressure gradient was at the boundary of the air column. The coal particles in different sizes had different residence time inside the cyclone. For the coal particles of same density, the smaller the particle size, the longer the residence time. The residence time of the discharged coal particles in the overflow in the cyclone was significantly longer than that from the underflow outlet. For coal particles discharged from the overflow outlet, the higher the density, the longer the residence time. While for coal particles discharged from the underflow outlet, the higher the density, the shorter the residence time. The structural parameters of different cyclones had different effects on separation process, and the influence of the diameter of the overflow pipe was the most significant. When the diameter of the overflow pipe exceeded 500 mm, a complete air column cannot be formed, resulting in failure to separation. When the diameter of the overflow pipe was 300 mm, the separation efficiency was better. In addition, the insertion depth of the over-flow pipe significantly affected the separation efficiency. When the insertion depth was 160 mm, the separation density increased, and the fine high-density coal particles would misplace into the overflow. When the insertion depth of the overflow was 320-800 mm, the separation density was close to the suspension density, Ep value was 0. 084-0. 100, and the separation efficiency was better. The diameter of the underflow outlet had a great influence on the separation precision of the cyclone. When the diameter was 272 mm and 306 mm, the separation density was close to the density of the suspension, and the Ep value was less than 0. 1, which had a better separation efficiency. The length of the cylindrical section had little effect on the separation density. [ABSTRACT FROM AUTHOR]

Silo is widely used in grain, logistics, electric power, metallurgy and other industries. Therefore, the reasonable design of silo structure is the key. China is a large country of grain production, with application of the modern granary environmental protection, energy saving, green and other concepts, the cylinder wall is higher, and larger diameter, occupies less land, saves resources of the silo and is more and more in line with the future development trend of granary, and with the trend of rapid development around the world. With the increasing height and diameter of silo, the problem of failure in silo discharging is becoming more prominent. The dynamic lateral pressure of grain silo during discharging is the major cause of silo failure. In this paper, based on the indoor grain silo discharging model test, the whole process of the silo center emptying was recorded with high-speed camera, the flow pattern of grain was analyzed with image processing technology, and the dynamic pressure generated during the discharge process was measured. Based on this test, the particle flow code (PFC3D) was used to carry out numerical simulation to track the movement of specific particles in the test. By comparing the results of the experiment and the numerical simulation, the mechanism of overpressure in the discharge of the silo was explored. Through this study, in the process of discharging in the center, there were two kinds of flow states, the mass flow and the tubular flow. At the beginning of the discharge, the stored material flowed as mass flow. After a period of time, the upper part of the material flowed as mass flow, the bottom of the storage was a tubular flow, and the mass flow was in the high diameter ratio close to 1 of the height position to convert to tubular flow. When the discharging height reached 1.1m, the stored material flowed in tubular flow until the discharge was completed. Both the dynamic lateral pressure and the static lateral pressure increased with the depth of the measuring point, and the dynamic lateral pressure was greater than the static lateral pressure. At the beginning of the discharge, the dynamic lateral pressure measured by the silo suddenly increased, and then the dynamic lateral pressure value decreased with the continuous reduction of the storage height. The overpressure coefficient measured by the three groups of sensors was larger in the height range of the high diameter ratio close to 1, and the overpressure phenomenon was obvious. In the process of silo discharging, the speed of tubular flow of the bottom stored material was greater than the speed of the mass flow of the middle and upper stored material. There was a pressure arch at the junction of the two flow states, and the existence of the pressurized arch hindered the normal flow of the upper stored material, which led to the self-weight of the stored material and the additional force caused by the change of momentum was almost entirely by the arch, resulting in the increase of the dynamic lateral pressure and a significant overpressure phenomenon. [ABSTRACT FROM AUTHOR]

The flotation microscopic model considers that the attachment behavior of coal particles and bubbles is the key step to achieve flotation. Therefore, the direct research on attachment behavior is very important. A device was designed by ourselves to directly measure the attachment behavior of coal particles and bubbles. In this paper, the raw coal of Inner Mongolia Gongwusu was taken as the experiment subjects and the attachment behavior of 0. 1-0. 15 mm coal samples with different densities was directly observed. Then, it was analised by the multi-target tracking software. The results showed that coal particles would flowed around the bubble before collision occurrence, and the velocity and direction of coal particles would changed. The velocity of coal particles decreased to minimum when coal particles colliding with bubble. The sliding velocity of coal particles on the bubble surface firstly increased gradually, and sliding velocity reached the maximum at the bubble "equator" position. After crossed the "equator", the sliding velocity of coal particles gradually decreased, and finally coal particles attached to the bottom of the bubble. The attachment efficiency of coal particles and bubbles decreased with the increase of collision angle. At the same collision angle, the attachment efficiency and the critical attachment angle decreased with the increase of coal density. With the increase of terminal velocity, both the attachment efficiency and the critical attachment angle decreased. Therefore, the regulation of the attachment efficiency of different density was verified. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper 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.)

Flow-like motion is the main forms of rock avalanche emplacement, which is the foundation to reveal the dynamic mechanisms of rock avalanches. In this paper, a series of physical modeling experiments based on the Particle Image Velocimetry（PIV）analysis method are conducted to research the internal velocity distribution, internal shear behavior and flow regimes of the granular flow under different grain size conditions. The flow-like motion of rock avalanches and the corresponding deposit features are further discussed and analyzed based on the experimental results. The research results show that the flow-like motion of the granular flow is significantly correlated with the grain size. With the decreasing grain size or the increasing fine particles content, the slip velocity at the bottom of the granular flow and the bulk velocity decrease gradually, the degree of internal shear of the granular flow increases, and the motion form of the granular materials changes from “sliding” to “flowing”. When the grain size is smaller or the content of fine particles is higher, the increasing trend of the internal shear rate is more prominent at the bottom of the granular flow, which indicates that the reduction in grain size promotes shear localization at the bottom of the granular flow. The granular flow regime is different at different locations of the granular flow. The leading and trailing edges of the granular flow are mainly inertial regime, and the interaction between particles is dominated by collisions, while the particle interactions in the main body is dominated by frictional contact. On the surface and bottom of the granular flow, the interaction between particles is mainly collision, while particle interaction in the middle part is mainly frictional contact. For the granular flow with different grain sizes, with the increasing grain size and coarse particles content, the particle collisions in the granular flow are enhanced, and the flow regimes tend to be more inertial.

Copyright of China Sciencepaper is the property of China Sciencepaper 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 granular flow thickness and its evolution trend are key factors in analyses of the physical model experiments of avalanches. At present, the measurements of granular flow thickness mainly include sensor monitoring, mechanical measurement and manual measurement. With the development of computer technology, digital image processing methods have been applied in more and more subjects including engineering geology. In this paper, a series of granular chute flow experiments are conducted for the extraction of granular flow thicknesses. Based on the digital image processing methods including adaptive median filter, image binarization, image erosion and seed filling, the granular flow image sequence recorded by the high-speed camera is processed and analysed with related codes compiled, thereby achieving continuous extraction of flow thickness during the granular flow propagation. The results show that the granular flow thicknesses extracted with the digital image processing methods are consistent with the measured true thicknesses in the main bodies of the granular flows. Some deviations appear in the tail of granular flow accompanied by significant particle dispersions. The deviations are mainly attributed to the fact that some particles in the three-dimensional space show overlapping phenomenon in the two-dimensional image, which results in the illusion of granular continuity. In general, the granular flow thicknesses obtained with the digital image processing methods is of a high accuracy in the densely packed granular flows. Compared with other methods, this method is of higher efficiency, higher sampling rate and lower disturbance on granular flows. In addition, additional parameters, such as velocities and displacement, can be obtained simultaneously. Therefore, this method can be used as one of the conventional methods to obtain kinematic parameters in granular flow experiments.

Copyright of China Sciencepaper is the property of China Sciencepaper 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 China Sciencepaper is the property of China Sciencepaper 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 China Sciencepaper is the property of China Sciencepaper 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 Applied Mathematics & Mechanics (1000-0887) is the property of Applied Mathematics & Mechanics 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.)