Based on the momentum and mass conservation equations, a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions, solution flow, gas flow, and solute tran...Based on the momentum and mass conservation equations, a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions, solution flow, gas flow, and solute transport within the leaching system. The governing equations are solved numerically using the COMSOL Multiphysics software for the coupled reactive flow and solute transport at micro-scale, meso-scale and macro-scale levels. At or near the surface of ore particle, the acid concentration is relatively higher than that in the central area, while the concentration gradient decreases after 72 d of leaching. The flow simulation between ore particles by combining X-ray CT technology shows that the highest velocity in narrow pore reaches 0.375 m/s. The air velocity within the dump shows that the velocity near the top and side surface is relatively high, which leads to the high oxygen concentration in that area. The coupled heat transfer and liquid flow process shows that the solution can act as an effective remover from the heap, dropping the highest temperature from 60 to 38 ℃. The reagent transfer coupled with solution flow is also analyzed. The results obtained allow us to obtain a better understanding of the fundamental physical phenomenon of the bioleaching process.展开更多
An equation of atomization quantity from energy dissipation by hydraulic jump was derived from the dimensional analysis. By applying Gauss diffusion equation, the spray diffusion rule in valley was studied under the c...An equation of atomization quantity from energy dissipation by hydraulic jump was derived from the dimensional analysis. By applying Gauss diffusion equation, the spray diffusion rule in valley was studied under the condition of continuous linear source and random wind direction.By considering the spray rain switching process, coagulation, condensation and evaporation of droplets, the air temperature, air relative humidity, spray density and the rainfall intensity in the lower reaches of the linear source were calculated. The 3 D numerical simulation fitted well with prototype monitoring. Finally, the prediction of atomization influence on environments for Xiangjiaba Hydropower Station was conducted.展开更多
Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penet...Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.展开更多
This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and v...This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and visualization of reconstructed 3D model by taking into account the shape measurement of 3D complex structures,and some experimental results are presented.展开更多
Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming p...Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.展开更多
This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and c...This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and concentration profiles in transient state. The mathematical model is developed for a fluidized bed solar reactor, taking into account dynamics conditions of heating and reaction. The heating was simulated for radiated flux with a normal distribution over lateral walls and with distributed flow conditions of the focal stain. The contraction and expansion effects of the bed were involved with a two dimensional distribution. The mathematical model of a solar fluidized bed reactor involves a reversible chemistry reaction of thermal dissociation of the zinc sulfate (ZnSO4), also the mathematical model is accomplished by a sensitivity study with regard to the gas inlet temperature and radiation flux.展开更多
Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis (TGA) and the differential...Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis (TGA) and the differential thermal analysis (DTA). Oxidation kinetic parameters were further investigated by model-fitting methods. The test results showed that the oxidation of spent catalysts was a quite mild process, while coal and coal char experienced sharp weight loss during oxidation. The temperature for commencement and termination of oxidation increased in the following order: coal〈coal char〈spent catalysts, and the oxidation of the three tested materials displayed a self-catalytic nature, with their largest oxidation rate appearing at a weight percent of 24.96%, 34.21% and 57.93%, respectively. The oxidation of spent catalysts obeyed a random nucleation model for the first-order reaction, with Ea=206.13 kJ/mol and lgA=10.10, and the oxidation of coal could be a diffusion-controlled reaction mechanism, with Ea=161.61 kJ/mol and lgA=7.74, while the oxidation of coal char also obeyed a random nucleation model for the first-order reaction, with Ea= 149.36 k J/mol and lgA=7.89.展开更多
In this paper, we consider the singular isothermal sphere lensing model that has a spherically symmetric power-law mass dis- tribution ρtot(r) - r-γ. We investigate whether the mass density power-law index y is co...In this paper, we consider the singular isothermal sphere lensing model that has a spherically symmetric power-law mass dis- tribution ρtot(r) - r-γ. We investigate whether the mass density power-law index y is cosmologically evolutionary by using the strong gravitational lensing (SGL) observation, in combination with other cosmological observations. We also check whether the constraint result of y is affected by the cosmological model, by considering several simple dynamical dark energy models. We find that the constraint on y is mainly decided by the SGL observation and independent of the cosmological model, and we find no evidence for the evolution of y from the SGL observation.展开更多
基金Projects(50934002,51104011) supported by the National Natural Science Foundation of ChinaProject(IRT0950) supported by Program for Changjiang Scholars and Innovative Research Team in Chinese UniversityProject(20100480200) supported by China Postdoctoral Science Foundation
文摘Based on the momentum and mass conservation equations, a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions, solution flow, gas flow, and solute transport within the leaching system. The governing equations are solved numerically using the COMSOL Multiphysics software for the coupled reactive flow and solute transport at micro-scale, meso-scale and macro-scale levels. At or near the surface of ore particle, the acid concentration is relatively higher than that in the central area, while the concentration gradient decreases after 72 d of leaching. The flow simulation between ore particles by combining X-ray CT technology shows that the highest velocity in narrow pore reaches 0.375 m/s. The air velocity within the dump shows that the velocity near the top and side surface is relatively high, which leads to the high oxygen concentration in that area. The coupled heat transfer and liquid flow process shows that the solution can act as an effective remover from the heap, dropping the highest temperature from 60 to 38 ℃. The reagent transfer coupled with solution flow is also analyzed. The results obtained allow us to obtain a better understanding of the fundamental physical phenomenon of the bioleaching process.
文摘An equation of atomization quantity from energy dissipation by hydraulic jump was derived from the dimensional analysis. By applying Gauss diffusion equation, the spray diffusion rule in valley was studied under the condition of continuous linear source and random wind direction.By considering the spray rain switching process, coagulation, condensation and evaporation of droplets, the air temperature, air relative humidity, spray density and the rainfall intensity in the lower reaches of the linear source were calculated. The 3 D numerical simulation fitted well with prototype monitoring. Finally, the prediction of atomization influence on environments for Xiangjiaba Hydropower Station was conducted.
基金Supported by the Hi-Tech. Research and Development Program of China (863) (2002AA649280, 2002AA304030), National Natural Science Foundation of China (No. 20206002), Beijing NOVA program (H013610250112), University Postdoctrate Research Foundation of Chin
文摘Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.
基金This work is supported by National Natural Science Foundationof China.(Grant No. 60275012)Natural Science Research Foundof Higher Education in Guangdong Province (Grant No. 04Z010)+1 种基金the Natural Science Foundation of Guangdong Province (GranNo. 06028584) the Research Project of Science & Technol-ogy from Shenzhen Government (Grant No.200619).
文摘This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and visualization of reconstructed 3D model by taking into account the shape measurement of 3D complex structures,and some experimental results are presented.
文摘Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.
文摘This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and concentration profiles in transient state. The mathematical model is developed for a fluidized bed solar reactor, taking into account dynamics conditions of heating and reaction. The heating was simulated for radiated flux with a normal distribution over lateral walls and with distributed flow conditions of the focal stain. The contraction and expansion effects of the bed were involved with a two dimensional distribution. The mathematical model of a solar fluidized bed reactor involves a reversible chemistry reaction of thermal dissociation of the zinc sulfate (ZnSO4), also the mathematical model is accomplished by a sensitivity study with regard to the gas inlet temperature and radiation flux.
文摘Oxidation of coke deposited on spent catalytic cracking catalysts was compared with that of coal and coal char via the non-isothermal oxidation means, i.e. the thermal-gravimetric analysis (TGA) and the differential thermal analysis (DTA). Oxidation kinetic parameters were further investigated by model-fitting methods. The test results showed that the oxidation of spent catalysts was a quite mild process, while coal and coal char experienced sharp weight loss during oxidation. The temperature for commencement and termination of oxidation increased in the following order: coal〈coal char〈spent catalysts, and the oxidation of the three tested materials displayed a self-catalytic nature, with their largest oxidation rate appearing at a weight percent of 24.96%, 34.21% and 57.93%, respectively. The oxidation of spent catalysts obeyed a random nucleation model for the first-order reaction, with Ea=206.13 kJ/mol and lgA=10.10, and the oxidation of coal could be a diffusion-controlled reaction mechanism, with Ea=161.61 kJ/mol and lgA=7.74, while the oxidation of coal char also obeyed a random nucleation model for the first-order reaction, with Ea= 149.36 k J/mol and lgA=7.89.
基金supported by the National Natural Science Foundation of China(Grant Nos.11522540,and 11690021)the Top-Notch Young Talents Program of China,and the Provincial Department of Education of Liaoning(Grant No.L2012087)
文摘In this paper, we consider the singular isothermal sphere lensing model that has a spherically symmetric power-law mass dis- tribution ρtot(r) - r-γ. We investigate whether the mass density power-law index y is cosmologically evolutionary by using the strong gravitational lensing (SGL) observation, in combination with other cosmological observations. We also check whether the constraint result of y is affected by the cosmological model, by considering several simple dynamical dark energy models. We find that the constraint on y is mainly decided by the SGL observation and independent of the cosmological model, and we find no evidence for the evolution of y from the SGL observation.