Based on such severe situation, we need to work out a way that enables us to analyze the current and future ability of a region to provide clean water to meet the needs of its population, and to develop a reasonable s...Based on such severe situation, we need to work out a way that enables us to analyze the current and future ability of a region to provide clean water to meet the needs of its population, and to develop a reasonable strategy to optimize the utilization of water resources in this area. This paper has worked out a resolution model and input the data of China, the United States, Russia, Laos and Afghanistan to do national testing. Then, we use the policy from “diaper incident” to do policy testing. The calculation results of the model are in conformity with the reality. Therefore, the model is effective. At last this model is used to resolve Gansu’s water problem and provide effective advices for the local government.展开更多
Some main ideas about the turning of the Changjiang River diluted water (CDW) and their deficiencies are reviewed in this paper. According to a large number of observation data it is pointed out that the turning pheno...Some main ideas about the turning of the Changjiang River diluted water (CDW) and their deficiencies are reviewed in this paper. According to a large number of observation data it is pointed out that the turning phenomena of the CDW are related not only to the discharge of the Changjiang River but also to the sea surface slope and wind stress curl in the southeast coast of China. Exsistence of the sea surface slope reflects essentially the effect of the Taiwan Warm Currc (TWC) on the turning of the CDW.展开更多
In this study,a one-dimensional two-phase flow four-equation model was developed to simulate the water faucet problem.The performance of six different Krylov subspace methods,namely the generalized minimal residual(GM...In this study,a one-dimensional two-phase flow four-equation model was developed to simulate the water faucet problem.The performance of six different Krylov subspace methods,namely the generalized minimal residual(GMRES),transpose-free quasi-minimal residual,quasi-minimal residual,conjugate gradient squared,biconjugate gradient stabilized,and biconjugate gradient,was evaluated with and without the application of an incomplete LU(ILU)factorization preconditioner for solving the water faucet problem.The simulation results indicate that using the ILU preconditioner with the Krylov subspace methods produces better convergence performance than that without the ILU preconditioner.Only the GMRES demonstrated an acceptable convergence performance under the Krylov subspace methods without the preconditioner.The velocity and pressure distribution in the water faucet problem could be determined using the Krylov subspace methods with an ILU preconditioner,while GMRES could determine it without the need for a preconditioner.However,there are significant advantages of using an ILU preconditioner with the GMRES in terms of efficiency.The different Krylov subspace methods showed similar performance in terms of computational efficiency under the application of the ILU preconditioner.展开更多
Pattern distribution characteristics of water ecology in Jilin Province are introduced, and provincial water ecology problems are revealed from river cut-off and wetland shrinkage, fish resources reduction and habitat...Pattern distribution characteristics of water ecology in Jilin Province are introduced, and provincial water ecology problems are revealed from river cut-off and wetland shrinkage, fish resources reduction and habitat fragmentation, water pollution, soil erosion and so on. Relevant suggestions on water ecology protection are proposed, such as implementing relevant laws and policies, controlling total sewage discharge, optimizing water resources allocation, and enhancing wetland protection, fish resources protection, comprehensive management of small watershed and water ecology compensation. The research could provide certain reference for protection and restoration of water ecology in the watershed.展开更多
With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of ...With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of contamination of waters used for human consumption by some chemical agents, and describing causes and modalities of contamination and human health implications. The chemical agents examined were herbicides, nitrates, trihalomethanes, asbestos, manganese and fluoride. In this paper a first nationwide picture of these problems is reported.展开更多
This study investigated a water supply recovery problem involving municipal water service piping. The problem consisted in recovering full service after network failure, in order to rapidly satisfy all urgent citywide...This study investigated a water supply recovery problem involving municipal water service piping. The problem consisted in recovering full service after network failure, in order to rapidly satisfy all urgent citywide demands. The optimal recovery solution was achieved through the application of so-called network design problems （NDPs）, which are a form of combinatorial optimization problem. However, a conventional NDP is not suitable for addressing urgent situations because （1） it does not utilize the non-failure arcs in the network, and （2） it is solely concerned with stable costs such as flow costs. Therefore, to adapt the technique to such urgent situations, the conventional NDP is here modified to deal with the specified water supply problem. In addition, a numerical illustration using the Sendai water network is presented.展开更多
Fresh water resources are a fundamental condition for mankind’s existence and social development.At present mankind is consuming the limited fresh water resources at an unprecedented scale and speed.From 1955 to 1990...Fresh water resources are a fundamental condition for mankind’s existence and social development.At present mankind is consuming the limited fresh water resources at an unprecedented scale and speed.From 1955 to 1990,the countries in the world short of water have amounted to 20 from seven. According to statistical figures from the UN Population Action International,by 2025,10-15 more countries will be short of water.展开更多
Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Lin...Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.展开更多
Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and...Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.展开更多
ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lew...ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lewy (CFL) coefficient. Toro and Titarev employed CCFL=0.95for their experiments. Nonetheless, we noted that the experiments conducted in this study with CCFL=0.95produced solutions exhibiting spurious oscillations, particularly in the high-order ADER-WAF schemes. The homogeneous one-dimensional (1D) non-linear Shallow Water Equations (SWEs) are the subject of these experiments, specifically the solution of the Riemann Problem (RP) associated with the SWEs. The investigation was conducted on four test problems to evaluate the ADER-WAF schemes of second, third, fourth, and fifth order of accuracy. Each test problem constitutes a RP characterized by different wave patterns in its solution. This research has two primary objectives. We begin by illustrating the procedure for implementing the ADER-WAF schemes for the SWEs, providing the required relations. Afterward, following comprehensive testing, we present the range for the CFL coefficient for each test that yields solutions with diminished or eliminated spurious oscillations.展开更多
China＇s economy develops very quickly; at the same time it faces severe environmental problems. Air and water pollution is the heaviest among them. This paper tries to analyze the reasons of the involving environment...China＇s economy develops very quickly; at the same time it faces severe environmental problems. Air and water pollution is the heaviest among them. This paper tries to analyze the reasons of the involving environmental problems in China and the government responses.展开更多
文摘Based on such severe situation, we need to work out a way that enables us to analyze the current and future ability of a region to provide clean water to meet the needs of its population, and to develop a reasonable strategy to optimize the utilization of water resources in this area. This paper has worked out a resolution model and input the data of China, the United States, Russia, Laos and Afghanistan to do national testing. Then, we use the policy from “diaper incident” to do policy testing. The calculation results of the model are in conformity with the reality. Therefore, the model is effective. At last this model is used to resolve Gansu’s water problem and provide effective advices for the local government.
文摘Some main ideas about the turning of the Changjiang River diluted water (CDW) and their deficiencies are reviewed in this paper. According to a large number of observation data it is pointed out that the turning phenomena of the CDW are related not only to the discharge of the Changjiang River but also to the sea surface slope and wind stress curl in the southeast coast of China. Exsistence of the sea surface slope reflects essentially the effect of the Taiwan Warm Currc (TWC) on the turning of the CDW.
文摘In this study,a one-dimensional two-phase flow four-equation model was developed to simulate the water faucet problem.The performance of six different Krylov subspace methods,namely the generalized minimal residual(GMRES),transpose-free quasi-minimal residual,quasi-minimal residual,conjugate gradient squared,biconjugate gradient stabilized,and biconjugate gradient,was evaluated with and without the application of an incomplete LU(ILU)factorization preconditioner for solving the water faucet problem.The simulation results indicate that using the ILU preconditioner with the Krylov subspace methods produces better convergence performance than that without the ILU preconditioner.Only the GMRES demonstrated an acceptable convergence performance under the Krylov subspace methods without the preconditioner.The velocity and pressure distribution in the water faucet problem could be determined using the Krylov subspace methods with an ILU preconditioner,while GMRES could determine it without the need for a preconditioner.However,there are significant advantages of using an ILU preconditioner with the GMRES in terms of efficiency.The different Krylov subspace methods showed similar performance in terms of computational efficiency under the application of the ILU preconditioner.
文摘Pattern distribution characteristics of water ecology in Jilin Province are introduced, and provincial water ecology problems are revealed from river cut-off and wetland shrinkage, fish resources reduction and habitat fragmentation, water pollution, soil erosion and so on. Relevant suggestions on water ecology protection are proposed, such as implementing relevant laws and policies, controlling total sewage discharge, optimizing water resources allocation, and enhancing wetland protection, fish resources protection, comprehensive management of small watershed and water ecology compensation. The research could provide certain reference for protection and restoration of water ecology in the watershed.
文摘With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of contamination of waters used for human consumption by some chemical agents, and describing causes and modalities of contamination and human health implications. The chemical agents examined were herbicides, nitrates, trihalomethanes, asbestos, manganese and fluoride. In this paper a first nationwide picture of these problems is reported.
文摘This study investigated a water supply recovery problem involving municipal water service piping. The problem consisted in recovering full service after network failure, in order to rapidly satisfy all urgent citywide demands. The optimal recovery solution was achieved through the application of so-called network design problems （NDPs）, which are a form of combinatorial optimization problem. However, a conventional NDP is not suitable for addressing urgent situations because （1） it does not utilize the non-failure arcs in the network, and （2） it is solely concerned with stable costs such as flow costs. Therefore, to adapt the technique to such urgent situations, the conventional NDP is here modified to deal with the specified water supply problem. In addition, a numerical illustration using the Sendai water network is presented.
文摘Fresh water resources are a fundamental condition for mankind’s existence and social development.At present mankind is consuming the limited fresh water resources at an unprecedented scale and speed.From 1955 to 1990,the countries in the world short of water have amounted to 20 from seven. According to statistical figures from the UN Population Action International,by 2025,10-15 more countries will be short of water.
文摘Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.
文摘Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.
文摘ADER-WAF methods were first introduced by researchers E.F. Toro and V.A. Titarev. The linear stability criterion for the model equation for the ADER-WAF schemes is CCFL≤1, where CCFLdenotes the Courant-Friedrichs-Lewy (CFL) coefficient. Toro and Titarev employed CCFL=0.95for their experiments. Nonetheless, we noted that the experiments conducted in this study with CCFL=0.95produced solutions exhibiting spurious oscillations, particularly in the high-order ADER-WAF schemes. The homogeneous one-dimensional (1D) non-linear Shallow Water Equations (SWEs) are the subject of these experiments, specifically the solution of the Riemann Problem (RP) associated with the SWEs. The investigation was conducted on four test problems to evaluate the ADER-WAF schemes of second, third, fourth, and fifth order of accuracy. Each test problem constitutes a RP characterized by different wave patterns in its solution. This research has two primary objectives. We begin by illustrating the procedure for implementing the ADER-WAF schemes for the SWEs, providing the required relations. Afterward, following comprehensive testing, we present the range for the CFL coefficient for each test that yields solutions with diminished or eliminated spurious oscillations.
文摘China＇s economy develops very quickly; at the same time it faces severe environmental problems. Air and water pollution is the heaviest among them. This paper tries to analyze the reasons of the involving environmental problems in China and the government responses.
