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
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
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
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
Water manufactured is the primary waste source in the oil and gas industry. Because of the rising amount of waste worldwide, the environmental effect of wastewater has become a primary environmental concern in recent ...Water manufactured is the primary waste source in the oil and gas industry. Because of the rising amount of waste worldwide, the environmental effect of wastewater has become a primary environmental concern in recent years. The vast amounts involved have resulted in considerable costs to the industry for handling produced water. This research explains the wide variety of choices for water management. This research’s first phase was water minimization techniques, consisting of three different applications made in three different wells (Well 1, Well 2 and Well 3) and water recycling and reuse by two techniques. In Well 1, Mechanical shut-off technique was applied using through tubing bridge plug and 5 m cement dumped above it to isolate the watered out zone;as per water oil ration plot the water cut is decreased from 100% to 4% and the production is increased from 0 to 400 bcpd. In Well 2, Chemical shut-off technique using a polymer called Brightwater has been used to block channeling through high permeability intervals after PLT log detected it, and the result was brilliant, the water cut decreased from 60% to 25%, also the oil production increase from 500 to 3000 bopd. In Well 3, downhole separator installed in it using workover (unfortunately, this technique is not applied in middle east till the moment so this application is taken from an oil field in Canada)and the result was perfect, the water cut decreased from 70% to 28%, also the oil production increase from 44 to 100 bopd. This study tried to clarify and compare the most widely used water management techniques using one of the Western Desert (W.D.) (enhanced for oil recovery, constructed wetland).展开更多
In our country, with the acceleration of the industrialization process, a large number of rural population has transferred to cities, and industry and agriculture have developed rapidly. However, the lack of awareness...In our country, with the acceleration of the industrialization process, a large number of rural population has transferred to cities, and industry and agriculture have developed rapidly. However, the lack of awareness of environmental protection and the lack of capacity for environmental protection have led to a series of water pollution problems. The discharge of many toxic and harmful substances in agricultural production activities will have a huge impact on the ecological environment and even threaten human health and safety. For example, the improper use of pesticides and fertilizers will cause heavy metals to exceed the standard, the white cigarette ends brought about by straw burning will also become "three wastes" to enter the water body for pollution, and the irrational discharge of nitrogenous and phosphate fertilizers from livestock and poultry breeding will cause eutrophication of the water quality, and other phenomena are constantly occurring for frequent treatment, among which the deterioration of the water environment quality in rural areas is one of the important factors in our country. At the same time, it also brings serious harm to human beings: eutrophication of water bodies, soil hardening and excessive heavy metal elements, etc., which are all caused by people's lack of awareness of environmental protection and limited scientific and technological level.展开更多
Water conservancy project is a very complex system engineering, and water seepage is inevitable during its construction. Seepage control technology is one of the important components in water conservancy and hydropowe...Water conservancy project is a very complex system engineering, and water seepage is inevitable during its construction. Seepage control technology is one of the important components in water conservancy and hydropower construction. It can reduce the waste of water resources, reduce environmental pollution and energy consumption, and play a positive role;At the same time, it also has a certain impact and improvement effect on people's quality of life;Combined with practical cases, this paper analyzes the shortcomings of anti-seepage measures in the specific application, and puts forward corresponding suggestions: Strengthen the design concept, reasonably control the cost of construction materials, strengthen project management, improve the quality level of construction personnel and management personnel, and standardize the operation process.展开更多
A new method to solve the boundary value problem arising in the study of scattering of two-dimensional surface water waves by a discontinuity in the surface boundary conditions is presented in this paper. The disconti...A new method to solve the boundary value problem arising in the study of scattering of two-dimensional surface water waves by a discontinuity in the surface boundary conditions is presented in this paper. The discontinuity arises due to the floating of two semi-infinite inertial surfaces of different surface densities. Applying Green＇s second identity to the potential functions and appropriate Green＇s functions, this problem is reduced to solving two coupled Fredholm integral equations with regular kernels. The solutions to these integral equations are used to determine the reflection and the transmission coefficients. The results for the reflection coefficient are presented graphically and are compared to those obtained earlier using other research methods. It is observed from the graphs that the results computed from the present analysis match exactly with the previous results.展开更多
This paper continues discussing the problems of numerically solving the shallow water circulation on the basis of ref. 1, For the numerical method proposed in ref. 1, we applied a storage method with dense matrices, w...This paper continues discussing the problems of numerically solving the shallow water circulation on the basis of ref. 1, For the numerical method proposed in ref. 1, we applied a storage method with dense matrices, which abandoned usual bandwidth concept and attained the intention of saving interior storage, computing time and amount of preparing work before computing. The circulation considered the effect of small islands was successfully simulated by specially dealing with the bottom friction terms and the boundary conditions. In addition, we discussed the action of bottom friction on the dissipation of tidal energy and its effect on stability of period motion.展开更多
In the present paper,two-and three-dimensional velocity potentials generated by pulsating pressure distributions of infinite extent on the free surface of infinite-depth waters are strictly derived based on special ca...In the present paper,two-and three-dimensional velocity potentials generated by pulsating pressure distributions of infinite extent on the free surface of infinite-depth waters are strictly derived based on special cases of concentrated pulsating pressure.The far-field asymptotic behaviour of the potentials and the radiation conditions to be satisfied by them are discussed. It is proved in a general sense that the potentials should be composed of a forced wave component,a free wave component and a local disturbance component.The radiation condition of the forced wave component should correspond to the far-field asymptotic behaviour of the pressure distribution,Hence,the formulation of radiation conditions for the second-order diffraction potentials has theoretically become clear,The radiation conditions for two-and three-dimensional problems are explicitly given in the paper.展开更多
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.
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Water manufactured is the primary waste source in the oil and gas industry. Because of the rising amount of waste worldwide, the environmental effect of wastewater has become a primary environmental concern in recent years. The vast amounts involved have resulted in considerable costs to the industry for handling produced water. This research explains the wide variety of choices for water management. This research’s first phase was water minimization techniques, consisting of three different applications made in three different wells (Well 1, Well 2 and Well 3) and water recycling and reuse by two techniques. In Well 1, Mechanical shut-off technique was applied using through tubing bridge plug and 5 m cement dumped above it to isolate the watered out zone;as per water oil ration plot the water cut is decreased from 100% to 4% and the production is increased from 0 to 400 bcpd. In Well 2, Chemical shut-off technique using a polymer called Brightwater has been used to block channeling through high permeability intervals after PLT log detected it, and the result was brilliant, the water cut decreased from 60% to 25%, also the oil production increase from 500 to 3000 bopd. In Well 3, downhole separator installed in it using workover (unfortunately, this technique is not applied in middle east till the moment so this application is taken from an oil field in Canada)and the result was perfect, the water cut decreased from 70% to 28%, also the oil production increase from 44 to 100 bopd. This study tried to clarify and compare the most widely used water management techniques using one of the Western Desert (W.D.) (enhanced for oil recovery, constructed wetland).
文摘In our country, with the acceleration of the industrialization process, a large number of rural population has transferred to cities, and industry and agriculture have developed rapidly. However, the lack of awareness of environmental protection and the lack of capacity for environmental protection have led to a series of water pollution problems. The discharge of many toxic and harmful substances in agricultural production activities will have a huge impact on the ecological environment and even threaten human health and safety. For example, the improper use of pesticides and fertilizers will cause heavy metals to exceed the standard, the white cigarette ends brought about by straw burning will also become "three wastes" to enter the water body for pollution, and the irrational discharge of nitrogenous and phosphate fertilizers from livestock and poultry breeding will cause eutrophication of the water quality, and other phenomena are constantly occurring for frequent treatment, among which the deterioration of the water environment quality in rural areas is one of the important factors in our country. At the same time, it also brings serious harm to human beings: eutrophication of water bodies, soil hardening and excessive heavy metal elements, etc., which are all caused by people's lack of awareness of environmental protection and limited scientific and technological level.
文摘Water conservancy project is a very complex system engineering, and water seepage is inevitable during its construction. Seepage control technology is one of the important components in water conservancy and hydropower construction. It can reduce the waste of water resources, reduce environmental pollution and energy consumption, and play a positive role;At the same time, it also has a certain impact and improvement effect on people's quality of life;Combined with practical cases, this paper analyzes the shortcomings of anti-seepage measures in the specific application, and puts forward corresponding suggestions: Strengthen the design concept, reasonably control the cost of construction materials, strengthen project management, improve the quality level of construction personnel and management personnel, and standardize the operation process.
基金Partially Supported by a DST Research Project to RG(No.SR/FTP/MS-020/2010)
文摘A new method to solve the boundary value problem arising in the study of scattering of two-dimensional surface water waves by a discontinuity in the surface boundary conditions is presented in this paper. The discontinuity arises due to the floating of two semi-infinite inertial surfaces of different surface densities. Applying Green＇s second identity to the potential functions and appropriate Green＇s functions, this problem is reduced to solving two coupled Fredholm integral equations with regular kernels. The solutions to these integral equations are used to determine the reflection and the transmission coefficients. The results for the reflection coefficient are presented graphically and are compared to those obtained earlier using other research methods. It is observed from the graphs that the results computed from the present analysis match exactly with the previous results.
文摘This paper continues discussing the problems of numerically solving the shallow water circulation on the basis of ref. 1, For the numerical method proposed in ref. 1, we applied a storage method with dense matrices, which abandoned usual bandwidth concept and attained the intention of saving interior storage, computing time and amount of preparing work before computing. The circulation considered the effect of small islands was successfully simulated by specially dealing with the bottom friction terms and the boundary conditions. In addition, we discussed the action of bottom friction on the dissipation of tidal energy and its effect on stability of period motion.
基金The present study is supported by the grant from the Natural Science Foundation of China.
文摘In the present paper,two-and three-dimensional velocity potentials generated by pulsating pressure distributions of infinite extent on the free surface of infinite-depth waters are strictly derived based on special cases of concentrated pulsating pressure.The far-field asymptotic behaviour of the potentials and the radiation conditions to be satisfied by them are discussed. It is proved in a general sense that the potentials should be composed of a forced wave component,a free wave component and a local disturbance component.The radiation condition of the forced wave component should correspond to the far-field asymptotic behaviour of the pressure distribution,Hence,the formulation of radiation conditions for the second-order diffraction potentials has theoretically become clear,The radiation conditions for two-and three-dimensional problems are explicitly given in the paper.
