The residual strains has produced by the first loadingunloading of coal are 7 × 10 −5, × 10 −4, and × 10 −4, respectively. ... However, if the loadingunloading process was continued beyond this point, the residual strain reappeared. The occurrence of the nonresidual strain phenomenon was found to be directly related to the ...
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A semicontinuous process system consisting of a singlebucket excavator, truck, crushing station, and belt conveyor is the main coal mining process system of a largescale hard coal openpit mine. Through analyzing the coal mining production process, the key issues of coal mining truck flow optimization are obtained. Statistical method of using triangular fuzzy numbers analyzes the key time ...
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The damage in coal cyclic loading was quantitatively characterized by the damage variables and damage constitutive equations based on electrical resistivity. The results show that the response of resistivity and DIC is regular and complementary. ... The results show that during the true triaxial cyclic loading and unloading process, the ...
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Experimental Device. The "gascontaining coal thermalfluidsolid coupling threeaxis servo seepage system" developed by Chongqing University (Fig. 2) was used to study the effect of variable confining pressure unloading rate on coal deformation and permeability characteristics during the alternate loading and unloading device has a maximum axial force of 1000 kN, a ...
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The rock mass in fault zones is frequently subjected to cyclic loading and unloading during deep resource exploitation and tunnel excavation. Research on the mechanical and hydraulic characteristics of fault rock during the cyclic loading and unloading is of great significance for revealing the formation mechanism of waterconducting pathways in fault and preventing water inrush disasters. In ...
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The coils are then loaded either on a reel style or cradle style uncoiling system. Cradle style uncoilers are relatively easy to load, you basically lower your coil onto the cradle, position the sides guides to center the coil and your coil is ready to be released. On a reel type the process is not as easy. You have a large heavy object either ...
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In this process, the coal in a protected seam is subjected to cyclic loadingunloading effects, which significantly change the mechanical properties and seepage characteristics of the coal. Related research results show that gas has a significant influence on the mechanical properties and energy dissipation characteristics of coal [ 17, 18 ...
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Both coal mining and tunnel excavation exhibit significant unloading effects, with the process of confining pressure unloading causing damage to coal, thereby affecting coal impact characteristics and gas outburst characteristics. 1820 Based on their investigation, Ding et al. 21 performed a stability assessment study of deep mine dynamic ...
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The D s characterizes the effect of a single loadingunloading cycle on a coal body permeability transformation. During the stress unloading process, the pore spaces in a coal body expand after it is unloaded from the highstress environment. The original fractures in a coal sample reopen during the effective stress reduction.
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In the process of coal formation, the internal structure is different from the occurrence of primary cracks. As a result, the new crack generation and primary crack development of different samples are affected to different degrees during loading and unloading. Energy characteristics under true triaxial loading and unloading
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Permeability changes with confining stress loadingunloading: (a) is the PUC; (b) is the cataclastic coal; (c) is the mylonitic coal; (d) is the loadingunloading process of confining stress. The increase in confining pressure compressed the coal matrix and internal fissures of the coal cores, and their permeability rapidly and then slowly ...
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True triaxial loadingunloading tests of coal samples were performed using a multifunctional true triaxial fluidsolid coupling experimental system. The deformation, seepage, damage, strength, and failure characteristics of the coal samples were analyzed. Based on this, the variation mechanism of the permeability and yield conditions under different gas pressures was investigated, and the ...
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The process of loading and unloading can involve heavy equipment, moving machinery, and manual labor, which increases the risk of accidents and injuries. It is crucial to provide comprehensive training, enforce safety protocols, and use proper personal protective equipment to minimize these risks. 2. Damage to cargo and vessel.
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To study the weakening process, deformation, and failure characteristics of rock masses surrounding deep chambers under complex stress environments, triaxial loading tests along with triaxial loading/unloading followed by uniaxial loading tests were conducted on sandstone specimens. The internal microcracks of the specimens under the loading and unloading of triaxial confining pressure were ...
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Thus, the axial stress in the experiment is equal to the confining stress. In this study, three loading and unloading seepage tests have been carried out to simulate the effect of three coal seams mining on the caving zone and the second and third loading and unloading stress paths are the same as the first loading and unloading stress path.
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The loading and unloading rate for uniaxial and cyclic fatigue load were mm/min. The Express8 AE monitoring system was adopted to continuously log the acoustic events/micro failure inside the coal samples during the whole loading process.
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Coal isn't carrying the burden for other commodities anywhere except on the subdivisions that are almost nothing but coal. At present, coal supplies % of electricity, nuclear %, natural gas %, oil %, hydro %, and other sources (mostly biomass, but also wind, geothermal, and solar) about %.
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A scheme of the uniaxial cyclic loading and unloading tests is shown in Fig. 2b. The test process used the displacement control method, and the loading and unloading rate was mm/min, with 6 ...
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Cyclic Loading and Unloading Process. Based on the results of AE filtering experimental results, the loading process for the ultrasonic test experiments carried out in this study is as follows: measure the ultrasonic wave parameters before the process of loading, load up to kN and maintain the force for 34 minutes; load up to kN and maintain the force for 34 minutes; unload up ...
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During the cyclic loading and unloading process, assuming that there was no energy exchange between the machine and the external environment, the test equipment transferred energy to the sample through mechanical work, part of which was converted into elastic energy stored inside the coal body, and could be completely released during unloading ...
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In this paper, the alternate loading and unloading by stages tests of raw coal samples were carried out by using the "Triaxial seepage test device of thermal fluid solid of coal and rock", the conclusions are as follows: The axial strain change rate ε 1 ′, the radial strain change rate ε 3 ′ and the permeability change rate k′ under unit stress state are used to represent the ...
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During the deformation process of coal under the combined highstatic confining pressure and axial disturbance loads, we found that the final instability failure of coal specimens, subjected to disturbance load, were more likely to occur in the disturbance loading and unloading stage, such as specimen SB1, and SD1.
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This is the technology that used in power plant, while the coal is unload to the convayer belt
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To further validate and promote the proposed damage constitutive model, the loadingunloading process of coal material is also simulated. Because energy is continuously transformed during loading, in the loadingunloading process, the damage variable is also defined by energy dissipation.
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During the loading/unloading process, the gas pressure in the coal sample is maintained constant through the ingenious structure design of the system. As shown in Fig. 2 b, the constantvolume chamber is connected to the sample by a gas tube, and the constantvolume pistons are connected to the axial indenter.
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Ship Cargo Handling, Loading, Unloading: A commercial ship is usually a link in a "trade route" between distant points. Goods flowing in the route must be transferred to and from the sea link; they must also be given care while aboard the ship, and in turn they must not be a hazard to the ship and its crew. Ancient cargo handling consisted almost exclusively of manually carrying cargo in ...
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Unloading PRB coal cars with a Dravo rotary dumper
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Both coal companies and Railways have envisaged to jointly ensure per day coal loading of 415 rakes of domestic coal and 30 rakes of imported coal to the power sector. 'In the current month ...
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Load restraint: Load restraint includes lashing/unlashing, tie down, twistlock locking/unlocking for the purposes of ensuring a load is secured to the truck to meet the performance standards in the load restraint guide or unsecured in preparation for removal. Safe zone: is an area free of interaction between equipment/machinery and people. The safe
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CAMTECH and RDSO to identify equipments which could be used for unloading coal ... During the process wagons are getting damaged due to following action of the ... Loading/unloading machines can be divided on the basis of dumping height and type of bucket. The equipment with a dumping height of about feet are called Dumpers or
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To study the anisotropic mechanical properties and energy evolution of layered rock masses under the action of cyclic loading, uniaxial graded cyclic loading and unloading tests under different upper and lower stress limits were carried out on samples with different bedding angles (0°, °, 45°, °, and 90°) to explore the deformation and mechanical response characteristics of bedded ...
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In the true triaxial cyclic mechanical experiment of coal, most of the total work done by the three principal stresses is accumulated in the coal with elastic potential energy (the elastic strain energy will be released in the unloading process of external force, approximately equal to the negative work done by the external force in the ...
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