Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist...Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (W<sub>ET</sub>), impact energy index (K<sub>E</sub>), as well as uniaxial compressive strength (R<sub>C</sub>). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index C<sub>EF</sub> as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.展开更多
Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist...Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (W<sub>ET</sub>), impact energy index (K<sub>E</sub>), as well as uniaxial compressive strength (R<sub>C</sub>). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index C<sub>EF</sub> as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.展开更多
The velocity profiles and separation efficiency curves of a hydrocyclone were predicted by an Euler-Euler approach using a computational fluid dynamics tool ANSYS-CFX 14.5. The Euler-Euler approach is capable of consi...The velocity profiles and separation efficiency curves of a hydrocyclone were predicted by an Euler-Euler approach using a computational fluid dynamics tool ANSYS-CFX 14.5. The Euler-Euler approach is capable of considering the particle-particle interactions and is appropriate for highly laden liquid-solid mixtures. Pre- dicted results were compared and validated with experi- mental results and showed a considerably good agreement. An increase in the particle cut size with increasing solid concentration of the inlet mixture flow was observed and discussed. In addition to this, the erosion on hydrocyclone walls constructed from stainless steel 410, eroded by sand particles (mainly SiOz), was predicted with the Euler-La- grange approach. In this approach, the abrasive solid particles were traced in a Lagrangian reference frame as discrete particles. The increases in the input flow velocity, solid concentration, and the particle size have increased the erosion at the upper part of the cylindrical body of the hydrocyclone, where the tangential inlet flow enters the hydrocyclone. The erosion density in the area between the cylindrical to conical body area, in comparison to other parts of the hydrocyclone, also increased considerably. Moreover, it was observed that an increase in the particle shape factor from 0.1 to 1.0 leads to a decrease of almost 70 % in the average erosion density of the hydrocyclone wall surfaces.展开更多
Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor inje...Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor injection. However, many issues have to be resolved before the commercial production. In the present study, a 2-D axisymmetric simulator for gas production from hydrate reservoirs is developed. The simulator includes equations of conductive and convective heat transfer, kinetic of hydrate decomposition, and multiphase flow. These equations are discretized based on the finite difference method and are solved with the fully implicit simultaneous solution method. The process of laboratory-scale hydrate decomposition by depressurization is simulated. For different surrounding temperatures and outlet pressures, time evolutions of gas and water generations during hydrate dissociation are evaluated, and variations of temperature, pressure, and multiphase fluid flow conditions are analyzed. The results suggest that the rate of heat transfer plays an important role in the process. Furthermore, high surrounding temperature and low outlet valve pressure may increase the rate of hydrate dissociation with insignificant impact on final cumulative gas volume.展开更多
Rutherford classical scattering theory, as its quantum mechanical analogue, is modified for scattering cross-section and the impact parameter by using quantum mechanical momentum, (de Broglie hypothesis), energy relat...Rutherford classical scattering theory, as its quantum mechanical analogue, is modified for scattering cross-section and the impact parameter by using quantum mechanical momentum, (de Broglie hypothesis), energy relationship for matter oscillator (Einstein’s oscillator) and quantum mechanical wave vectors, and , respectively. It is observed that the quantum mechanical scattering cross-section and the impact parameter depended on inverse square law of quantum action (Planck’s constant). Born approximation is revisited for quantum mechanical scattering. Using Bessel and Neumann asymptotic functions and response of nuclear surface potential barrier, born approximations were modified. The coulombic fields inside the nucleus of the atom are studied for reflection and transmission with corresponding wave vectors, phase shifts and eigenfunctions Bulk quantum mechanical tunneling and reflection scattering, both for ruptured and unruptured nucleus of the atom, are deciphered with corresponding wave vectors, phase shifts and eigenfunction. Similar calculation ware accomplished for quantum surface tunneling and reflection scattering with corresponding wave vectors, phase shifts and eigenfunctions. Such diverse quantum mechanical scattering cross-section with corresponding wave vectors for tunneling and reflection, phase shifts and eigenfunctions will pave a new dimension to understanding the behavior of exchange fields in the nucleus of the atom with insides layers both ruptured and unruptured. Phase shifts, δ<sub>l</sub> for each of the energy profile (partial) will be different and indeed their corresponding wave vectors for exchange energy eigenvalues.展开更多
Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter p...Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we have calculated the impact parameter and beam energy dependence for azimuthal asymmetry, characterized by directed transverse flow parameter F and elliptic asymmetry coeffcient v2, of direct photons and the corresponding free protons in intermediate energy heavy-ion collisions. It is further shown the anti-correlated azimuthal asymmetry between direct photons and free protons.展开更多
The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u 40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model. The nucleo...The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u 40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model. The nucleon- number scaling of elliptic flow exists and the scaling of the ratios of v4/v2 2 and v3/(v1v2) is applicable to collisions at almost all impact parameters except for peripheral collisions.展开更多
In this study,Au+Au collisions with an impact parameter of 0≤b≤12.5 fm at√(s_(NN))=200 GeV are simulated using the AMPT model to provide preliminary final-state information.After transforming this information into ...In this study,Au+Au collisions with an impact parameter of 0≤b≤12.5 fm at√(s_(NN))=200 GeV are simulated using the AMPT model to provide preliminary final-state information.After transforming this information into appropriate input data(the energy spectra of final-state charged hadrons),we construct a multi-layer perceptron(MLP)and convolutional neural network(CNN)to connect final-state observables with the impact parameters.The results show that both the MLP and CNN can reconstruct the impact parameters with a mean absolute error approximately 0.4 fm,although the CNN behaves slightly better.Subsequently,we test the neural networks at different beam energies and pseudorapidity ranges in this task.These two models work well at both low and high energies.However,when conducting a test for a larger pseudorapidity window,the CNN exhibits a higher prediction accuracy than the MLP.Using the Grad-CAM method,we shed light on the'attention'mechanism of the CNN model.展开更多
In this paper, the p meson impact parameter dependent parton distributions and the impact parameter dependent form factors are introduced and discussed. By employing a Gaussian form wave packet, we calculate the impac...In this paper, the p meson impact parameter dependent parton distributions and the impact parameter dependent form factors are introduced and discussed. By employing a Gaussian form wave packet, we calculate the impact parameter distributions of the p meson based on a light-cone constituent quark model.展开更多
A phenomenological Lagrangian approach is employed to study the electromagnetic properties of deuteron The deuteron is regarded as a loosely bound state of a proton and a neutron. The deuteron electromagnetic form fac...A phenomenological Lagrangian approach is employed to study the electromagnetic properties of deuteron The deuteron is regarded as a loosely bound state of a proton and a neutron. The deuteron electromagnetic form factors are expressed in light-front representation in the transverse plane. The transverse charge density of the deuteron is discussed.展开更多
This paper presents a new empirical formula to calculate the average nucleon-nucleon (N-N) collisi011 number for the total reaction cross sections (aR). Based on the initial average N-N collision number calculated...This paper presents a new empirical formula to calculate the average nucleon-nucleon (N-N) collisi011 number for the total reaction cross sections (aR). Based on the initial average N-N collision number calculated by quantum molecular dynamics (QMD), quantum correction and Coulomb correction are taken into account within it. The average N-N collision number is calculated by this empirical formula. The total reaction cross sections are obtained within the framework of the Glauber theory, aR of 23A1+1:C, anAl+12C, 25A1+12C, 26A1+12C and 27A1+12C are calculated in the range of low energy. We also calculate the an of 27A1+12C with different incident e^ergies. The calculated aR are compared with the experimental data and the results of Glauber theory including the aa of both spherical nuclear and deformed nuclear. It is seen that the calculated aR are larger than GR of spherical nuclear and smaller than aa of deformed nuclear, whereas the results agree well with the experimental data in low-energy range.展开更多
文摘Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (W<sub>ET</sub>), impact energy index (K<sub>E</sub>), as well as uniaxial compressive strength (R<sub>C</sub>). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index C<sub>EF</sub> as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.
文摘Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (W<sub>ET</sub>), impact energy index (K<sub>E</sub>), as well as uniaxial compressive strength (R<sub>C</sub>). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index C<sub>EF</sub> as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.
基金“Stiftung Rheinland-Pfalz fur Innovation,Mainz,Germany,”for financial support
文摘The velocity profiles and separation efficiency curves of a hydrocyclone were predicted by an Euler-Euler approach using a computational fluid dynamics tool ANSYS-CFX 14.5. The Euler-Euler approach is capable of considering the particle-particle interactions and is appropriate for highly laden liquid-solid mixtures. Pre- dicted results were compared and validated with experi- mental results and showed a considerably good agreement. An increase in the particle cut size with increasing solid concentration of the inlet mixture flow was observed and discussed. In addition to this, the erosion on hydrocyclone walls constructed from stainless steel 410, eroded by sand particles (mainly SiOz), was predicted with the Euler-La- grange approach. In this approach, the abrasive solid particles were traced in a Lagrangian reference frame as discrete particles. The increases in the input flow velocity, solid concentration, and the particle size have increased the erosion at the upper part of the cylindrical body of the hydrocyclone, where the tangential inlet flow enters the hydrocyclone. The erosion density in the area between the cylindrical to conical body area, in comparison to other parts of the hydrocyclone, also increased considerably. Moreover, it was observed that an increase in the particle shape factor from 0.1 to 1.0 leads to a decrease of almost 70 % in the average erosion density of the hydrocyclone wall surfaces.
基金supported by the National High Technology Research and Development Program of China(863 Program, Grant No.2006AA09A209-5)the National Natural Science Foundation of China (Key Program,Grant No.50736001)the Major Research Project of Ministry of Education of China (Grant No.306005)
文摘Natural gas hydrate, as a potential energy resource, deposits in permafrost and marine sediment with large quantities. The current exploitation methods include depressurization, thermal stimulation, and inhibitor injection. However, many issues have to be resolved before the commercial production. In the present study, a 2-D axisymmetric simulator for gas production from hydrate reservoirs is developed. The simulator includes equations of conductive and convective heat transfer, kinetic of hydrate decomposition, and multiphase flow. These equations are discretized based on the finite difference method and are solved with the fully implicit simultaneous solution method. The process of laboratory-scale hydrate decomposition by depressurization is simulated. For different surrounding temperatures and outlet pressures, time evolutions of gas and water generations during hydrate dissociation are evaluated, and variations of temperature, pressure, and multiphase fluid flow conditions are analyzed. The results suggest that the rate of heat transfer plays an important role in the process. Furthermore, high surrounding temperature and low outlet valve pressure may increase the rate of hydrate dissociation with insignificant impact on final cumulative gas volume.
文摘Rutherford classical scattering theory, as its quantum mechanical analogue, is modified for scattering cross-section and the impact parameter by using quantum mechanical momentum, (de Broglie hypothesis), energy relationship for matter oscillator (Einstein’s oscillator) and quantum mechanical wave vectors, and , respectively. It is observed that the quantum mechanical scattering cross-section and the impact parameter depended on inverse square law of quantum action (Planck’s constant). Born approximation is revisited for quantum mechanical scattering. Using Bessel and Neumann asymptotic functions and response of nuclear surface potential barrier, born approximations were modified. The coulombic fields inside the nucleus of the atom are studied for reflection and transmission with corresponding wave vectors, phase shifts and eigenfunctions Bulk quantum mechanical tunneling and reflection scattering, both for ruptured and unruptured nucleus of the atom, are deciphered with corresponding wave vectors, phase shifts and eigenfunction. Similar calculation ware accomplished for quantum surface tunneling and reflection scattering with corresponding wave vectors, phase shifts and eigenfunctions. Such diverse quantum mechanical scattering cross-section with corresponding wave vectors for tunneling and reflection, phase shifts and eigenfunctions will pave a new dimension to understanding the behavior of exchange fields in the nucleus of the atom with insides layers both ruptured and unruptured. Phase shifts, δ<sub>l</sub> for each of the energy profile (partial) will be different and indeed their corresponding wave vectors for exchange energy eigenvalues.
基金Supported by National Basic Research Program of China (973 Program) (2007CB815004)Shanghai Development Foundation from Science and Technology (06JC14082, 06QA14062)National Natural Science Foundation of China (10535010, 10775167)
文摘Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we have calculated the impact parameter and beam energy dependence for azimuthal asymmetry, characterized by directed transverse flow parameter F and elliptic asymmetry coeffcient v2, of direct photons and the corresponding free protons in intermediate energy heavy-ion collisions. It is further shown the anti-correlated azimuthal asymmetry between direct photons and free protons.
文摘The scaling behaviors of anisotropic flows of light charged particles are studied for 25 MeV/u 40Ca+40Ca collisions at different impact parameters by the isospin-dependent quantum molecular dynamics model. The nucleon- number scaling of elliptic flow exists and the scaling of the ratios of v4/v2 2 and v3/(v1v2) is applicable to collisions at almost all impact parameters except for peripheral collisions.
基金Supported by the National Natural Science Foundation of China(12075061)Shanghai NSF(20ZR1404100)。
文摘In this study,Au+Au collisions with an impact parameter of 0≤b≤12.5 fm at√(s_(NN))=200 GeV are simulated using the AMPT model to provide preliminary final-state information.After transforming this information into appropriate input data(the energy spectra of final-state charged hadrons),we construct a multi-layer perceptron(MLP)and convolutional neural network(CNN)to connect final-state observables with the impact parameters.The results show that both the MLP and CNN can reconstruct the impact parameters with a mean absolute error approximately 0.4 fm,although the CNN behaves slightly better.Subsequently,we test the neural networks at different beam energies and pseudorapidity ranges in this task.These two models work well at both low and high energies.However,when conducting a test for a larger pseudorapidity window,the CNN exhibits a higher prediction accuracy than the MLP.Using the Grad-CAM method,we shed light on the'attention'mechanism of the CNN model.
基金Supported by National Natural Science Foundation of China(11475192)the fund provided to the Sino-German CRC 110 "Symmetries and the Emergence of Structure in QCD" project by the NSFC(11621131001)the Key Research Program of Frontier Sciences,CAS(Y7292610K1)
文摘In this paper, the p meson impact parameter dependent parton distributions and the impact parameter dependent form factors are introduced and discussed. By employing a Gaussian form wave packet, we calculate the impact parameter distributions of the p meson based on a light-cone constituent quark model.
基金Supported by National Natural Science Foundation of China(10975146,11035006,11261130,11165005)DFGthe NSFC through funds provided to the Sino-Germen CRC 110"Symmetries and the Emergence of Structure in QCD"
文摘A phenomenological Lagrangian approach is employed to study the electromagnetic properties of deuteron The deuteron is regarded as a loosely bound state of a proton and a neutron. The deuteron electromagnetic form factors are expressed in light-front representation in the transverse plane. The transverse charge density of the deuteron is discussed.
基金National Natural Science Foundation of China (10905041)Innovation Fund Project for Graduate Student of Shanghai (JWCXSL1202)
文摘This paper presents a new empirical formula to calculate the average nucleon-nucleon (N-N) collisi011 number for the total reaction cross sections (aR). Based on the initial average N-N collision number calculated by quantum molecular dynamics (QMD), quantum correction and Coulomb correction are taken into account within it. The average N-N collision number is calculated by this empirical formula. The total reaction cross sections are obtained within the framework of the Glauber theory, aR of 23A1+1:C, anAl+12C, 25A1+12C, 26A1+12C and 27A1+12C are calculated in the range of low energy. We also calculate the an of 27A1+12C with different incident e^ergies. The calculated aR are compared with the experimental data and the results of Glauber theory including the aa of both spherical nuclear and deformed nuclear. It is seen that the calculated aR are larger than GR of spherical nuclear and smaller than aa of deformed nuclear, whereas the results agree well with the experimental data in low-energy range.