Current Issue : April - June Volume : 2020 Issue Number : 2 Articles : 5 Articles
Rockburst is a sudden and dynamic failure of rock that can cause serious injury to miners and damage to the underground\nexcavations. Stress path, dynamic disturbance, and support system play important and different roles in the generation processes\nof rockbursts, resulting rockbursts with variety of reasons and failure modes. A test facility that was capable of simulating such\nfactors was developed to study shock behaviour and bursting failure of roadways. The results demonstrate that the modeled\nroadway was in good condition and retained a shock resistance capacity after three drop loads. Until the acceleration amplitude\nincreased to a certain level at the time of the fourth dynamic loading, sudden bursting failure of modeled roadway occurred. Many\nlarge fragments ejected from the upper and middle regions of the roadway, accompanied with loud noise. A deep pit was observed\nafter the bursting failure. The axial of the fan-shaped pit had an angle above the vertical. In addition, shock behaviour of the\nmodeled roadway had been changed by the anchor-net support. Significant differences appeared between the acceleration signals\nmeasured in two roadway sections with and without the anchor-net support. The acceleration magnitude of the supported\nroadway section was strongly reduced by the presence of the anchor-net support. Even when the unsupported roadway section\nunderwent a sudden injection failure, the roadway with anchor-net support was in good condition. This study may eventually lead\nto a methodology for studying the rockbursting resistance capacity of underground roadways....
We have developed an energy balance equation for the universe. The two\nsystem parameters involved in the equation could be â??fine-tunedâ? so that the\npredicted temperature histories all lead to what is observed in the present\ncosmic microwave background. We have shown that various combinations of\nthese two parameters are possible; in particular, the present background temperature\nneeds not be the remnant of a very hot temperature in the far distance\npast. We also solved for the propagation of vortex solitons in optical fibres\nas contrasting examples to show how electromagnetic wave could be\ntransmitted in a particular waveform under strictly controlled conditions. To\navoid singularity, all vortexes have a black centre. We conclude that while\nnumerical techniques can be used to account for an infinite quantity, it is\nunlikely that such a quantity could exist in reality....
In this paper, a new approach to modeling the hysteresis phenomenon of the open circuit\nvoltage (OCV) of lithium-ion batteries and estimating the battery state of charge (SoC) is presented.\nA characterization procedure is proposed to identify the battery model parameters, in particular,\nthose related to the hysteresis phenomenon and the transition between charging and discharging\nconditions. A linearization method is used to obtain a suitable trade-off between the model\naccuracy and a low computational cost, in order to allow the implementation of SoC estimation on\ncommon hardware platforms. The proposed characterization procedure and the model\neffectiveness for SoC estimation are experimentally verified using a real grid-connected storage\nsystem. A mixed algorithm is adopted for SoC estimation, which takes into account both the\ntraditional Coulomb counting method and the developed model. The experimental comparison\nwith the traditional approach and the obtained results show the feasibility of the proposed\napproach for accurate SoC estimation, even in the presence of low-accuracy measurement\ntransducers....
The paper suggests an approach to modeling the electrocoagulation process that is based on the generalization of the equations of\nincompressible fluid flow in nonisothermal conditions. In the model was taking into account the ratio between the values of the\nparameters which characterize the domination of convective and mass-exchange components of the process over diffusion. An\nasymptotic approximation of solutions of corresponding boundary value problems is constructed. Based on the received solutions,\nwe conducted a computer simulation of the process of distribution of iron concentration inside the reactor that allows predicting\nvarious hydrodynamic phenomena such as internal recirculation and dead zones that affect the formation of a coagulant. The\ninfluence of current strength on the concentration of the target component at the exit from the reactor was investigated using the\ndeveloped mathematical model. In addition, our findings also show the effect of the rate of heat formation from the electrodes on\nthe efficiency of obtaining of coagulant....
Thermal behavior of integrated passive components has become an important\nissue when designing these components. This paper presents the thermal\nmodeling of a multilayer integrated LC filter used in DC-DC step-down converter\nfor temperature distribution calculation. The approach used for this\nanalysis is based on thermal equivalent circuit. Temperature distribution is\nobtained from algebraic equation, which is in vector and matrix form. The\nresults of analytical calculation are compared with simulation results from finite\nelement method. These results showed a good correlation....
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