WEBOct 8, 2019 · Discussion on bulk carrier loading and unloading operations and freight safety for the owner's and master's responsibilities and obligations as per charter Party requirements. Master's Thesis, Department of Shipping Technology, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan, 2018.
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WEBSep 1, 2022 · The mining of coal resources causes the stress on the front and both sides of the working face to be in a complex loading and unloading process, and the gas contained in the coal body migrates ...
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WEBNov 1, 2023 · Coalrock combinations is a composite structure often encountered in mining engineering. At present, the research on coalrock combinations mainly focuses on the loading mechanical properties. However, when mining engineering involves excavation, the mechanical characteristics of the coalrock combination during unloading are very .
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WEBJan 22, 2024 · Su 21 studied the AE and damage characteristics of coal and rock under cyclic loading. ... There is an energy conversion process for loading and unloading rocks. Based on the principle of energy ...
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WEBMay 14, 2024 · This study investigates the stability of an artificial dam used in an underground reservoir in a coal mine under periodic weighting imposed by overlying rock strata. For this purpose, cyclic loading and unloading tests with different stress amplitudes were designed. Differences in the mechanical performance of the artificial dam with and .
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WEBDec 3, 2021 · As a result, the crack of saturated coal samples cannot keep stationary in the initial stage of loading and unloading and it slips throughout the loading and unloading process. A large number of macrotensile cracks appeared in the failed coal samples with pore water, as the pore pressure provides tensile force to the cracks and promotes the ...
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WEBResearch on energy and damage evolution patterns of gascontaining coal under constricting pressure unloading conditions is urgently needed in the process of deep underground mining and is crucial for understanding the mechanisms underlying coal and gas composite rockburst occurrences. Prior reaching peak stress, cyclic loading and .
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WEBThe permeability characteristics of a broken coal mass under repeated loading and unloading conditions exert significance on spontaneous combustion of coal in goaf during the mining of coal seam groups. Considering this, by using the seepage test system for broken coalrock mass, seepage tests under cyclic loading and unloading .
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WEBFeb 27, 2023 · The damage and fracture of coal is accompanied by a complex energy conversion process, and these different stages of energy evolution are closely related to coal failure. In this paper, an evolution model describing the behavior of coal failure was proposed using the energy dissipation under cyclic loading/unloading. The energy .
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WEBAs the coal body has a hysteresis effect during the unloading process, it cannot be unloaded to 0 when unloading, and the minimum unloading level was set for the four kinds of samples; that is, after unloading to 2% σ c, the loading was performed until the sample was destabilized.
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WEBUnloading and loading freight happens so often that workers and management can become complacent to the inherent dangers that exist in the process. Unloading and loading freight is almost always under some sort of time constraint. This issue and tighter supply chain windows can exacerbate the problem and create an even more dangerous .
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WEBMar 12, 2023 · The load–unload tests of coalrock combination were carried out in this study, and the specific setting is as follows: Scheme I conventional triaxial compression test. ... In addition, in the process of unloading confining pressure, the axial strain of the sample changes little before failure, and it starts to increase significantly when ...
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WEBJun 1, 2015 · Fig. 3 (a) compares the deviatoric stress–strain complete process in coal I under both constant and unloading confining pressures. Fig. 3 (b) plots the complete process of coal II under only unloading confining pressure. Firstly, the deviatoric stress–strain complete process is observed to be almost identical before the loading .
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WEBOct 10, 2022 · Permeability changes with confining stress loading–unloading: (a) is the PUC; (b) is the aclastic coal; (c) is the mylonitic coal; (d) is the loading–unloading 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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WEBAug 20, 2022 · The strain of coal mainly occurs in the first loading process. Compaction occurs largely during the loading process, and the fracture closure during this stage is mainly irreversible plastic deformation. The volume and morphology of the sample after unloading cannot be fully restored to the situation at the initial loading stage.
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WEBNov 18, 2022 · The results of cyclic loading–unloading experiments demonstrate that there is a correlation between the damage process caused by moisture content and stress in coal samples, and the evolution of dissipation energy and the development of hysteresis loops are both related to the presence of the characteristic stress σ'. The RA–AF ster ...
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WEBJun 1, 2020 · In the loadingunloading tests, the PER value was calculated based on the initial porosity and the relative increment in the volumetric strain during the whole loadingunloading process. A lower ...
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WEBApr 28, 2017 · During the postpeak loading and unloading process, the flow rate of the coal sample will decrease with the loading of confining pressure but increase with the unloading of confining pressure, and ...
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WEBThe hulls of tankers (as described above; see Types of ships: Tankers) are subdivided into a number of cells, or tanks, into which the liquid cargo is pumped through hoses by pumps mounted on the shore. Unloading is effected in the reverse manner by pumps mounted within the ship. Usually the only external cargohandling gear is a pair of cranes ...
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WEBDec 1, 2019 · This loadingunloading process can also occur in roomandpillar mines as the cascading pillar failure occurs. Fig. 1 (c) shows a series of gascontained pillars each subject to the same tributary area loading. If one of the weak pillars fails (Fig. 1 (c1)), the load will transfer to neighboring pillars causing an abrupt pillar loading .
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WEBIn the excavation process, the coal pillar will undergo shear failure due to repeated loading and unloading from mining stress. Meanwhile, plastic flow will occur after shear failure. The permeability change of the coal pillar under plastic flow is closely related to the loading path. Through a permeability test of the coal sample after shear yielding under .
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WEBFeb 1, 2021 · The samples collected from Banxi coal mine in Chongqing, Southwest China, have been used to study on damage of coal based on permeability change rate (PCR) and loadunload response ratio (LURR ...
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WEBDec 15, 2023 · A novel permeability model under triaxial pressure loading–unloading was developed. • The influence of effective stress and adsorption/desorption is considered in model. • The model is verified using test results of coal seepage under three conditions. • Triaxial pressure loading–unloading has a significant effect on coal permeability.
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WEBFeb 8, 2019 · Rock burst is a astrophic dynamic disaster caused by sudden failure and instability of coal, loading paths play an important role in the failure of coal, the coal failure process is associated with charge exception information. Hence, violent coal failure mechanics and time–frequency domain distribution of charge signal such as rock burst .
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WEBOct 31, 2019 · 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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WEBJul 11, 2022 · The change of elastic modulus of coal samples with the moisture. content of % is the largest in the first and sixth cyclic loading–unloading, decreasing. Mpa and Mpa ...
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WEBJan 1, 2020 · In the coal mining process, the stress state of the coal seam will change due to unloading caused by coal mininginduced, which may lead to the occurrence of coal and gas outburst disasters.
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WEBJan 22, 2024 · Protective seam mining is the most economical and effective measure for eliminating coal and gas herniation. To study the unloading effect of the mining of a protective seam on the protected layer, and to better grasp the effect of the protective layer on the abatement, conventional triaxial tests were conducted on coal samples with the .
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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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