To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals l...To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals like Cd and Pb in solid waste in mining areas and across the water body,sediment,soil and agricultural product ecosystem surrounding the mining areas.Focusing on the residual solid waste samples in lead-zinc deposits in a certain area of Guizhou Province,along with samples of topsoils,irrigation water,river sediments,and crops from surrounding areas.This study analyzed the distributions of eight heavy metals,i.e.,Cd,As,Cr,Hg,Pb,Zn,Cu,and Ni,in the samples through field surveys and sample tests.Furthermore,this study assessed the contamination levels and ecological risks of heavy metals in soils,sediments,and agricultural products using methods such as the single-factor index,Nemerow composite index,and potential ecological risk assessment.The results indicate that heavy metals in the solid waste samples all exhibited concentrations exceeding their risk screening values,with 60%greater than their risk intervention values.The soils and sediments demonstrate slight and moderate comprehensive ecological risks of heavy metals.The single-factor potential ecological risks of heavy metals in both the soil and sediment samples decreased in the order of Hg,Cd,Pb,As,Cu,Zn,Cr,and Ni,suggesting the same sources of heavy metals in the soils and sediments.Most of the agricultural product samples exhibited over-limit concentrations of heavy metals dominated by Cd,Pb,Ni,and Cr,excluding Hg and As.The agricultural product assessment using the Nemerow composite index reveals that 35%of the agricultural product samples reached the heavy metal contamination level,implying that the agricultural products from farmland around the solid waste dumps have been contaminated with heavy metals.The eight heavy metals in the soil,sediment,and agricultural product samples manifested high coefficients of variation(CVs),indicating pronounced spatial variability.This suggests that their concentrations in soils,sediments,and agricultural products are significantly influenced by human mining activities.Additionally,the agricultural products exhibit strong transport and accumulation capacities for Cd,Cu,and Zn.展开更多
We present a novel methodology and strategy to predict pressures and flow rates in the global cardiovascular network in different postures varying from supine to upright. A closed-loop, multiscale mathematical model o...We present a novel methodology and strategy to predict pressures and flow rates in the global cardiovascular network in different postures varying from supine to upright. A closed-loop, multiscale mathematical model of the entire cardiovascular system (CVS) is developed through an integration of one-dimensional (1D) modeling of the large systemic arteries and veins, and zero-dimensional (0D) lumped-parameter modeling of the heart, the cardiac-pulmonary circulation, the cardiac and venous valves, as well as the microcirculation. A versatile junction model is proposed and incorporated into the 1D model to cope with splitting and/or merging flows across a multibranched junction, which is validated to be capable of estimating both subcritical and supercritical flows while ensuring the mass conservation and total pressure continuity. To model gravitational effects on global hemodynamics during postural change, a robust venous valve model is further established for the 1D venous flows and distributed throughout the entire venous network with consideration of its anatomically realistic numbers and locations. The present integrated model is proven to enable reasonable prediction of pressure and flow rate waveforms associated with cardiopulmonary circulation, systemic circulation in arteries and veins, as well as microcirculation within normal physiological ranges, particularly in mean venous pressures, which well match the in vivo measurements. Applications of the cardiovascular model at different postures demonstrate that gravity exerts remarkable influence on arterial and venous pressures, venous returns and cardiac outputs whereas venous pressures below the heart level show a specific correlation between central venous and hydrostatic pressures in right atrium and veins.展开更多
Although Brassica juncea (Indian mustard) is reported to be a good accumulator of metals, little is known of the selected varieties of B. juncea (cvs. Rai and BARI-11). This paper investigates the phytoaccumulation of...Although Brassica juncea (Indian mustard) is reported to be a good accumulator of metals, little is known of the selected varieties of B. juncea (cvs. Rai and BARI-11). This paper investigates the phytoaccumulation of arsenic, cadmium and lead by B. juncea (cvs. Rai and BARI-11) parents and F1 hybrids. The experiment was conducted in the hydroponic media in the greenhouse of University of Southampton under a Randomised Block Design. Sodium arsenite, cadmium sulphate and lead nitrate with 0 ppm, 0.5 ppm and 1 ppm were used. The cadmium treated plants were analysed by Varian Atomic absorption spectrophotometer-200. The samples of arsenic and lead were analysed by Inductively Coupled Plasma Atomic Emission Spectrophotometer. The results suggest that arsenic was detected only in the root systems while cadmium and lead were detected both in the root and shoot systems. Significant differences in the uptake were observed for different concentrations. Accumulation of arsenic was detected only in the root systems of B. juncea (cvs. Rai and BARI-11) at lower concentrations. Hence, this can be used as an agriculturally viable and efficient phytoaccumulator in the arsenic affected areas where contamination level is low and the contamination occurs at the rooting level.展开更多
Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A rea...Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A real-world origin-destination demand matrix survey was conducted in Boston,MA to identify the number of peak hour passing vehicles in the case study.Findings–The results showed that as the number of CVs(MPR)in the network increases,the total delay time decreases by an average of 14%and the fuel consumption decreases by an average of 56%,respectively,from scenarios 3 to 15 compared to scenario 2.Research limitations/implications–The first limitation of this study was considering a small network.The considered network shows a small part of the case study.Originality/value–This study can be a milestone for future research regarding gradual deployment of CVs’effects on transport networks.Efficient policy(s)may define based on the results of this network for Brockton transport network.展开更多
In this paper,the high-order space-time discontinuous Galerkin cell vertex scheme(DG-CVS)developed by the authors for hyperbolic conservation laws is extended for time dependent diffusion equations.In the extension,th...In this paper,the high-order space-time discontinuous Galerkin cell vertex scheme(DG-CVS)developed by the authors for hyperbolic conservation laws is extended for time dependent diffusion equations.In the extension,the treatment of the diffusive flux is exactly the same as that for the advective flux.Thanks to the Riemannsolver-free and reconstruction-free features of DG-CVS,both the advective flux and the diffusive flux are evaluated using continuous information across the cell interface.As a result,the resulting formulation with diffusive fluxes present is still consistent and does not need any extra ad hoc techniques to cure the common“variational crime”problem when traditional DG methods are applied to diffusion problems.For this reason,DG-CVS is conceptually simpler than other existing DG-typed methods.The numerical tests demonstrate that the convergence order based on the L_(2)-norm is optimal,i.e.O(h^(p+1))for the solution and O(h^(p))for the solution gradients,when the basis polynomials are of odd degrees.For even-degree polynomials,the convergence order is sub-optimal for the solution and optimal for the solution gradients.The same odd-even behaviour can also be seen in some other DG-typed methods.展开更多
This paper presents a novel high-order space-time method for hyperbolic conservation laws.Two important concepts,the staggered space-time mesh of the space-time conservation element/solution element(CE/SE)method and t...This paper presents a novel high-order space-time method for hyperbolic conservation laws.Two important concepts,the staggered space-time mesh of the space-time conservation element/solution element(CE/SE)method and the local discontinuous basis functions of the space-time discontinuous Galerkin(DG)finite element method,are the two key ingredients of the new scheme.The staggered spacetime mesh is constructed using the cell-vertex structure of the underlying spatial mesh.The universal definitions of CEs and SEs are independent of the underlying spatial mesh and thus suitable for arbitrarily unstructured meshes.The solution within each physical time step is updated alternately at the cell level and the vertex level.For this solution updating strategy and the DG ingredient,the new scheme here is termed as the discontinuous Galerkin cell-vertex scheme(DG-CVS).The high order of accuracy is achieved by employing high-order Taylor polynomials as the basis functions inside each SE.The present DG-CVS exhibits many advantageous features such as Riemann-solver-free,high-order accuracy,point-implicitness,compactness,and ease of handling boundary conditions.Several numerical tests including the scalar advection equations and compressible Euler equations will demonstrate the performance of the new method.展开更多
文摘To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals like Cd and Pb in solid waste in mining areas and across the water body,sediment,soil and agricultural product ecosystem surrounding the mining areas.Focusing on the residual solid waste samples in lead-zinc deposits in a certain area of Guizhou Province,along with samples of topsoils,irrigation water,river sediments,and crops from surrounding areas.This study analyzed the distributions of eight heavy metals,i.e.,Cd,As,Cr,Hg,Pb,Zn,Cu,and Ni,in the samples through field surveys and sample tests.Furthermore,this study assessed the contamination levels and ecological risks of heavy metals in soils,sediments,and agricultural products using methods such as the single-factor index,Nemerow composite index,and potential ecological risk assessment.The results indicate that heavy metals in the solid waste samples all exhibited concentrations exceeding their risk screening values,with 60%greater than their risk intervention values.The soils and sediments demonstrate slight and moderate comprehensive ecological risks of heavy metals.The single-factor potential ecological risks of heavy metals in both the soil and sediment samples decreased in the order of Hg,Cd,Pb,As,Cu,Zn,Cr,and Ni,suggesting the same sources of heavy metals in the soils and sediments.Most of the agricultural product samples exhibited over-limit concentrations of heavy metals dominated by Cd,Pb,Ni,and Cr,excluding Hg and As.The agricultural product assessment using the Nemerow composite index reveals that 35%of the agricultural product samples reached the heavy metal contamination level,implying that the agricultural products from farmland around the solid waste dumps have been contaminated with heavy metals.The eight heavy metals in the soil,sediment,and agricultural product samples manifested high coefficients of variation(CVs),indicating pronounced spatial variability.This suggests that their concentrations in soils,sediments,and agricultural products are significantly influenced by human mining activities.Additionally,the agricultural products exhibit strong transport and accumulation capacities for Cd,Cu,and Zn.
基金supported by a Grant-in-Aid for Scientific Research (Grant 17300141)Japan Society for the Promotion of Science and Research and Development of the Next Generation Integrated Simulation of Living Matter, JST,a part of the Development and Use of the Next Generation Supercomputer Project of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japanthe RIKEN Junior Research Associate Program
文摘We present a novel methodology and strategy to predict pressures and flow rates in the global cardiovascular network in different postures varying from supine to upright. A closed-loop, multiscale mathematical model of the entire cardiovascular system (CVS) is developed through an integration of one-dimensional (1D) modeling of the large systemic arteries and veins, and zero-dimensional (0D) lumped-parameter modeling of the heart, the cardiac-pulmonary circulation, the cardiac and venous valves, as well as the microcirculation. A versatile junction model is proposed and incorporated into the 1D model to cope with splitting and/or merging flows across a multibranched junction, which is validated to be capable of estimating both subcritical and supercritical flows while ensuring the mass conservation and total pressure continuity. To model gravitational effects on global hemodynamics during postural change, a robust venous valve model is further established for the 1D venous flows and distributed throughout the entire venous network with consideration of its anatomically realistic numbers and locations. The present integrated model is proven to enable reasonable prediction of pressure and flow rate waveforms associated with cardiopulmonary circulation, systemic circulation in arteries and veins, as well as microcirculation within normal physiological ranges, particularly in mean venous pressures, which well match the in vivo measurements. Applications of the cardiovascular model at different postures demonstrate that gravity exerts remarkable influence on arterial and venous pressures, venous returns and cardiac outputs whereas venous pressures below the heart level show a specific correlation between central venous and hydrostatic pressures in right atrium and veins.
文摘Although Brassica juncea (Indian mustard) is reported to be a good accumulator of metals, little is known of the selected varieties of B. juncea (cvs. Rai and BARI-11). This paper investigates the phytoaccumulation of arsenic, cadmium and lead by B. juncea (cvs. Rai and BARI-11) parents and F1 hybrids. The experiment was conducted in the hydroponic media in the greenhouse of University of Southampton under a Randomised Block Design. Sodium arsenite, cadmium sulphate and lead nitrate with 0 ppm, 0.5 ppm and 1 ppm were used. The cadmium treated plants were analysed by Varian Atomic absorption spectrophotometer-200. The samples of arsenic and lead were analysed by Inductively Coupled Plasma Atomic Emission Spectrophotometer. The results suggest that arsenic was detected only in the root systems while cadmium and lead were detected both in the root and shoot systems. Significant differences in the uptake were observed for different concentrations. Accumulation of arsenic was detected only in the root systems of B. juncea (cvs. Rai and BARI-11) at lower concentrations. Hence, this can be used as an agriculturally viable and efficient phytoaccumulator in the arsenic affected areas where contamination level is low and the contamination occurs at the rooting level.
文摘Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A real-world origin-destination demand matrix survey was conducted in Boston,MA to identify the number of peak hour passing vehicles in the case study.Findings–The results showed that as the number of CVs(MPR)in the network increases,the total delay time decreases by an average of 14%and the fuel consumption decreases by an average of 56%,respectively,from scenarios 3 to 15 compared to scenario 2.Research limitations/implications–The first limitation of this study was considering a small network.The considered network shows a small part of the case study.Originality/value–This study can be a milestone for future research regarding gradual deployment of CVs’effects on transport networks.Efficient policy(s)may define based on the results of this network for Brockton transport network.
基金This work is supported by the U.S.Air Force Office of Scientific Research(AFOSR)Computational Mathematics Programunder the Award No.FA9550-08-1-0122 and the Award No.FA9550-10-1-0045.The authors are also grateful to the School of Engineering and the Department of Computer Engineering at Jackson State University for their support.
文摘In this paper,the high-order space-time discontinuous Galerkin cell vertex scheme(DG-CVS)developed by the authors for hyperbolic conservation laws is extended for time dependent diffusion equations.In the extension,the treatment of the diffusive flux is exactly the same as that for the advective flux.Thanks to the Riemannsolver-free and reconstruction-free features of DG-CVS,both the advective flux and the diffusive flux are evaluated using continuous information across the cell interface.As a result,the resulting formulation with diffusive fluxes present is still consistent and does not need any extra ad hoc techniques to cure the common“variational crime”problem when traditional DG methods are applied to diffusion problems.For this reason,DG-CVS is conceptually simpler than other existing DG-typed methods.The numerical tests demonstrate that the convergence order based on the L_(2)-norm is optimal,i.e.O(h^(p+1))for the solution and O(h^(p))for the solution gradients,when the basis polynomials are of odd degrees.For even-degree polynomials,the convergence order is sub-optimal for the solution and optimal for the solution gradients.The same odd-even behaviour can also be seen in some other DG-typed methods.
基金This work is supported by the U.S.Air Force Office of Scientific Research(AFOSR)Computational Mathematics Program under the Award No.FA9550-08-1-0122.
文摘This paper presents a novel high-order space-time method for hyperbolic conservation laws.Two important concepts,the staggered space-time mesh of the space-time conservation element/solution element(CE/SE)method and the local discontinuous basis functions of the space-time discontinuous Galerkin(DG)finite element method,are the two key ingredients of the new scheme.The staggered spacetime mesh is constructed using the cell-vertex structure of the underlying spatial mesh.The universal definitions of CEs and SEs are independent of the underlying spatial mesh and thus suitable for arbitrarily unstructured meshes.The solution within each physical time step is updated alternately at the cell level and the vertex level.For this solution updating strategy and the DG ingredient,the new scheme here is termed as the discontinuous Galerkin cell-vertex scheme(DG-CVS).The high order of accuracy is achieved by employing high-order Taylor polynomials as the basis functions inside each SE.The present DG-CVS exhibits many advantageous features such as Riemann-solver-free,high-order accuracy,point-implicitness,compactness,and ease of handling boundary conditions.Several numerical tests including the scalar advection equations and compressible Euler equations will demonstrate the performance of the new method.
