Acid mine drainage（AMD） is commonly treated by neutralization with alkaline substances.This treatment is supported by titration experiments that illustrate the buffering mechanisms and estimate the base neutralizati...Acid mine drainage（AMD） is commonly treated by neutralization with alkaline substances.This treatment is supported by titration experiments that illustrate the buffering mechanisms and estimate the base neutralization capacity（BNC） of the AMD.Detailed explanation of titration curves requires modeling with a hydro-chemical model.In this study the titration curves of water samples from the drainage of the As Pontes mine and the corresponding dumps have been investigated and six buffers are selerted by analyzing those curves.Titration curves have been simulated by a reactive transport model to discover the detailed buffering mechanisms.These simulations show seven regions involving different buffering mechanism.The BNC is primarily from buffers of dissolved Fe,Al and hydrogen sulfate.The BNC can be approximated by：BNC = 3（C_（Fe） ＋ C_（Al）） ＋ 0.05C_（sulfate）,where the units are mol/L.The BNC of the sample from the mine is 9.25×10^（-3） mol/L and that of the dumps sample is 1.28×10^（-2） mol/L展开更多
In this paper,we study the problem of irreversible investment under endowment constraints.We first establish the existence and uniqueness of the result and then demonstrate the necessity and sufficient conditions for ...In this paper,we study the problem of irreversible investment under endowment constraints.We first establish the existence and uniqueness of the result and then demonstrate the necessity and sufficient conditions for optimality.Based on this condition,we provide a characterization for optimal investment plans,which can be obtained by the so-called base capacity solving a backward equation.We may obtain explicit solutions for certain typical cases.展开更多
Despite the promising energy storage capabilities of high-capacity silicon-and tin-based alloys,as well as fast-charging hard carbon anodes for lithium-ion batteries(LIBs),their widespread industrial adoption is limit...Despite the promising energy storage capabilities of high-capacity silicon-and tin-based alloys,as well as fast-charging hard carbon anodes for lithium-ion batteries(LIBs),their widespread industrial adoption is limited by low initial Coulombic efficiency(ICE).This primarily arises from active lithium loss during the first cycle,caused by the solid electrolyte interface(SEI)formation on anode surfaces and other irreversible side reactions[1,2].展开更多
Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized...Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method （DEM） was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.展开更多
文摘Acid mine drainage（AMD） is commonly treated by neutralization with alkaline substances.This treatment is supported by titration experiments that illustrate the buffering mechanisms and estimate the base neutralization capacity（BNC） of the AMD.Detailed explanation of titration curves requires modeling with a hydro-chemical model.In this study the titration curves of water samples from the drainage of the As Pontes mine and the corresponding dumps have been investigated and six buffers are selerted by analyzing those curves.Titration curves have been simulated by a reactive transport model to discover the detailed buffering mechanisms.These simulations show seven regions involving different buffering mechanism.The BNC is primarily from buffers of dissolved Fe,Al and hydrogen sulfate.The BNC can be approximated by：BNC = 3（C_（Fe） ＋ C_（Al）） ＋ 0.05C_（sulfate）,where the units are mol/L.The BNC of the sample from the mine is 9.25×10^（-3） mol/L and that of the dumps sample is 1.28×10^（-2） mol/L
基金supported by the Natural Science Foundation of Shandong Province (No. ZR2022QA022)the Natural Science Foundation of Shandong Province for Excellent Young Scientists Fund Program (Overseas)(No.2023HWYQ-049)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Qilu Young Scholars Program of Shandong University.
文摘In this paper,we study the problem of irreversible investment under endowment constraints.We first establish the existence and uniqueness of the result and then demonstrate the necessity and sufficient conditions for optimality.Based on this condition,we provide a characterization for optimal investment plans,which can be obtained by the so-called base capacity solving a backward equation.We may obtain explicit solutions for certain typical cases.
基金supported by the National Key R&D Program of China(2022YFA1504100)the National Natural Science Foundation of China(22125903,22439003,and 22409192)+2 种基金Liaoning Revitalization Talents Program—Leading Talents(XLYC2402032)the Science and Technology Major Project of Liaoning Province(2024JH1/11700012),DICP(DICP I202324,DICP I202471)the State Key Laboratory of Catalysis(2024SKL-A-001).
文摘Despite the promising energy storage capabilities of high-capacity silicon-and tin-based alloys,as well as fast-charging hard carbon anodes for lithium-ion batteries(LIBs),their widespread industrial adoption is limited by low initial Coulombic efficiency(ICE).This primarily arises from active lithium loss during the first cycle,caused by the solid electrolyte interface(SEI)formation on anode surfaces and other irreversible side reactions[1,2].
文摘Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method （DEM） was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.
