The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibratio...The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity （ETC） of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design （CCD） is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.展开更多
The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the fin...The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.展开更多
South-central Chile has some potential mineral resources including radioactive and rare earth elements (REE) minerals. This study reports some basic characteristics of the mineralogy of a radioactive-rare earth elemen...South-central Chile has some potential mineral resources including radioactive and rare earth elements (REE) minerals. This study reports some basic characteristics of the mineralogy of a radioactive-rare earth elements occurrence, related to a pegmatitic outcrop “Vertientes Pegmatite” hosted on Paleozoic granitic rocks of the South Coastal Batholith and discusses potential areas for REE deposits, particularly beach placers along the coastline of the BioBío region. In this pegmatite, X-ray diffraction analysis shows uranium-bearing minerals such as coffinite and metaschoepite, along with microcline, anorthoclase, albite, quartz and illite. Through optical microscopy and electron probe micro-analyzer (EPMA), rare earth minerals (monazite and xenotime) and radioactive minerals (thorite and thorium silicate ± uranium) were identified. Additionally, granitic rocks of the South Coastal Batholith around this pegmatite show rare earth minerals (monazite and allanite).展开更多
We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art...We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art literature related to the subject, in order to cross, to compare, and to organize the relevant contents to create a logical and consistent support to the finds. We show that it is consistent to assume that persistent hyperglycemia and diabetes mellitus can have precursors not only in pancreas, but also in brain, mainly induced by noxious dysfunctions of hypothalamus sensor neurons circuits and external noxious elements, causing pancreas overload, and the consequent exhaustion—overburden.展开更多
This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, nor...This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash (ranging from 6.4% to 12.73%), a high content of volatile matter (33.32-37.45%) and high gross calorific values (7430-8880 kcal/kg). The mineral matter of the coal samples studied is made up of dolomite (>90%), quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively correlated with ash content suggesting an association with inorganic constituents. Based on statistical analyses, concentrations of trace elements such as Co (51.3 10-6 -152.9 10-6 ), Ba (368 10-6 -3297.4 10-6 ), Cr (65.5 10-6 -194.2 10-6 ), Mo (5.6 10-6 -18.2 10-6 ), Ni (72.9 10-6 -152.9 10-6 ) and V (245.5 10-6 -520 10-6 ) are higher than world coal averages. However, low concentration of some volatile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.展开更多
Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evo...Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evolution, and damage mechanics to simulate the growth of central cracks in cathode particles（Li Mn_2 O_4） by an extended finite element method by considering the influence of multiple factors. The simulation shows that particles are likely to crack at a high discharge rate, when the particle radius is large, or when the initial central crack is longer. It also shows that the maximum principal tensile stress decreases and cracking becomes more difficult when the influence of crack surface diffusion is considered. The fracturing process occurs according to the following stages： no crack growth, stable crack growth, and unstable crack growth. Changing the charge/discharge strategy before unstable crack growth sets in is beneficial to prevent further capacity fading during electrochemical cycling.展开更多
Using the concept of the interactive water rock- microbe system of ocean floor, the microbialmineralization of ocean-floor polymetallic concretions in the central Pacific Ocean has been studied for the firsttime. Thro...Using the concept of the interactive water rock- microbe system of ocean floor, the microbialmineralization of ocean-floor polymetallic concretions in the central Pacific Ocean has been studied for the firsttime. Through the correlation and study of the microbial activity and formation mechanism of polymetallicconcretions, the microbial and chemical processes for. transforming mineralizing materials and the observationand determination of the concentration of mineralizing material in the system and the variation ofenvironmental parameters, this paper reveals the reaction rate and evolutionary direction of mineralizing com-ponents caused by microbial activity, expounds the microbial mineralization mechanism and formation modelof polymetallic concretions from the angle of microbial geochemical action, and suggests a threefold division ofthe microbial mineralization stages展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51105092,61403106)International Science and Technology Cooperation Program of China(Grant No.2014DFR50250)the 111 Project,China(Grant No.B07018)
文摘The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity （ETC） of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design （CCD） is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.
文摘The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.
文摘South-central Chile has some potential mineral resources including radioactive and rare earth elements (REE) minerals. This study reports some basic characteristics of the mineralogy of a radioactive-rare earth elements occurrence, related to a pegmatitic outcrop “Vertientes Pegmatite” hosted on Paleozoic granitic rocks of the South Coastal Batholith and discusses potential areas for REE deposits, particularly beach placers along the coastline of the BioBío region. In this pegmatite, X-ray diffraction analysis shows uranium-bearing minerals such as coffinite and metaschoepite, along with microcline, anorthoclase, albite, quartz and illite. Through optical microscopy and electron probe micro-analyzer (EPMA), rare earth minerals (monazite and xenotime) and radioactive minerals (thorite and thorium silicate ± uranium) were identified. Additionally, granitic rocks of the South Coastal Batholith around this pegmatite show rare earth minerals (monazite and allanite).
文摘We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art literature related to the subject, in order to cross, to compare, and to organize the relevant contents to create a logical and consistent support to the finds. We show that it is consistent to assume that persistent hyperglycemia and diabetes mellitus can have precursors not only in pancreas, but also in brain, mainly induced by noxious dysfunctions of hypothalamus sensor neurons circuits and external noxious elements, causing pancreas overload, and the consequent exhaustion—overburden.
基金supported by the Iranian Institute for Geological Surveys and Mineral Exploration
文摘This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash (ranging from 6.4% to 12.73%), a high content of volatile matter (33.32-37.45%) and high gross calorific values (7430-8880 kcal/kg). The mineral matter of the coal samples studied is made up of dolomite (>90%), quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively correlated with ash content suggesting an association with inorganic constituents. Based on statistical analyses, concentrations of trace elements such as Co (51.3 10-6 -152.9 10-6 ), Ba (368 10-6 -3297.4 10-6 ), Cr (65.5 10-6 -194.2 10-6 ), Mo (5.6 10-6 -18.2 10-6 ), Ni (72.9 10-6 -152.9 10-6 ) and V (245.5 10-6 -520 10-6 ) are higher than world coal averages. However, low concentration of some volatile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.
基金support of the National Natural Science Foundation of China (11472165 and 11332005)
文摘Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evolution, and damage mechanics to simulate the growth of central cracks in cathode particles（Li Mn_2 O_4） by an extended finite element method by considering the influence of multiple factors. The simulation shows that particles are likely to crack at a high discharge rate, when the particle radius is large, or when the initial central crack is longer. It also shows that the maximum principal tensile stress decreases and cracking becomes more difficult when the influence of crack surface diffusion is considered. The fracturing process occurs according to the following stages： no crack growth, stable crack growth, and unstable crack growth. Changing the charge/discharge strategy before unstable crack growth sets in is beneficial to prevent further capacity fading during electrochemical cycling.
文摘Using the concept of the interactive water rock- microbe system of ocean floor, the microbialmineralization of ocean-floor polymetallic concretions in the central Pacific Ocean has been studied for the firsttime. Through the correlation and study of the microbial activity and formation mechanism of polymetallicconcretions, the microbial and chemical processes for. transforming mineralizing materials and the observationand determination of the concentration of mineralizing material in the system and the variation ofenvironmental parameters, this paper reveals the reaction rate and evolutionary direction of mineralizing com-ponents caused by microbial activity, expounds the microbial mineralization mechanism and formation modelof polymetallic concretions from the angle of microbial geochemical action, and suggests a threefold division ofthe microbial mineralization stages
