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1.
Water resource shortages, water environmental deterioration, and water ecological degradation are becoming increasingly prominent in the Haihe River Basin under the effects of global climate change and intense human activity. Finding ways to solve these problems reasonably is an urgent task in basin water resources management. The water cycle describes the formation and transformation of every water drop, while it interacts with associated water ecology and water environment processes. Therefore, to fundamentally solve the above problems, the three processes must be combined and the evolutionary trends of the ecology and water environment driven by the water cycle must be determined. To comprehensively diagnose and solve the problems of water resources, ecology and water environment in the basin, an integrated simulation platform of the dualistic water cycle and its associated processes in the Haihe River Basin was established by fully analyzing the "natural-social" dualistic characteristics of the evolution of the basin water cycle in this study. Accordingly, it is a supporting tool to evaluate the future trends of water resources, ecology and the water environment by setting scenarios based on the predictions of a climate mode and water control conditions. The results show that with climate change, the water consumption, groundwater overexploitation, and the amount of water flowing to the sea could develop soundly and satisfy the requirements of national economic growth in the future planning year 2030 through the implementation of water consumption control management and the South-North Water Diversion Project. Meanwhile, associated water environmental deterioration can be alleviated, and a growing trend for production capacities of the natural ecosystem and agro-ecosystem is seen. The above results provide a foundation for implementing basin water resources regulation and the most strict water resources management.  相似文献   

2.
This paper presents a study of the middle route of the South-North Water Diversion Project. The middle route runs through the Northern China plain, where the water shortages are the most severe. There is not only a shortage of water for human usage, but also a shortage of ecological water. Although the current plan for the middle route is strictly focused on supplying water for residential and industrial use, the water can also potentially be used for ecological purposes. This paper evaluates the potential ecological benefits that can be brought to the fragile ecology in northern China by the middle route, in addition to the water supplied to residences and industry. The study describes ecological benefits of the middle route project, such as mitigation of groundwater extraction in the region and positive influences on the climate, the ecological uses of the middle route project itself, such as creating artificial niches along the channel and directly using the channel for ecological purposes, and the ecological uses of the water along the middle route such as diversion of the water into dyer channels that have suffered from drought conditions for decades.  相似文献   

3.
Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated.  相似文献   

4.
Results from past pollution control practices show that environmental quality can be ensured by controlling the actual amount of pollutants formed in the environment.Therefore,the marine environmental capacity for heavy metals was introduced.Marine environmental capacity for heavy metals is defined as the maximum amount of heavy metals permitted in the marine environment system to preserve the benign cycle of materials in the oceansphere,and to limit the adverse effects of heavy metals on the biosphere,hydrosphere,atmosphere,and lithosphere.Based on the box or three-dimensional model in the target coastal region,including the self-purification and output of heavy metals,the marine environmental capacity for heavy metals can be calculated within a given criterion and time.In this study,a method was proposed to calculate the marine environmental capacity for heavy metals which includes four steps:(1) gathering the basis information of target coastal ecosystem,(2) selection of water control points and water quality criteria for these points,(3) development of numerical models for the biogeochemical cycling of heavy metals in target coastal region,and(4) calculation of environmental capacity using the developed model.According to the proposed method,the marine environmental capacity for lead is approximately 60 tons per year if Grade I seawater quality is set as the control criterion in Jiaozhou Bay.An effective seawater quality management plan can also be framed based on the environmental capacity for metals.  相似文献   

5.
Tundish is an important metallurgical reactor in the continuous casting process. In order to control the fluid flow in tundish and thus take full advantage of the residencetime available for the removal of inclusions from molten steel, the effect of weir and dam on the fluid flow has been studied in a water model based on the characteristic number Froude and Reynold number similarity criteria. The residence time distribution curves of the flow were measured by SG800. The optimum arrangement of darn and weir and the nonstationary flow in tundish were discussed. The results show that the combination of weir and dam is benefit for the flow pattern in tundish, weir can prevent the upper recirculating flow, dam can cut off the bottom flow and turn to upwards, it is advantageous to separate the nonmetallic inclusions. Furthermore, it is important to exceed the critical depth of bath during exchange ladles, not only for the inclusion floatation but also for avoiding tundish slag drainage earlier.  相似文献   

6.
The assessment of water security is an important content in the security management of water resources due to the fact that the state of water security directly affects both the sustainable development of regional economy and the improvement on the living quality of mankind.Grey associative analysis is introduced and applied to assessment of water security on the basis of grey characteristics of the assessment index system of water security.As a case study shows,grey associative analysis is used for evaluating water security of some provinces in China,and the satisfactory assessment results are obtained.The sequence of provinces in China with regard to water security from good to poor is obtained and,moreover,the water security level of each region is also confirmed.The results obtained accord with the actual state of each region.They are of practical significance and can be used to guide the management of regional water security and a sustainable development of the economy therein.At the same time,the results demonstrate that grey associative analysis provides a new method for assessing water security quantitatively but needs a further study.  相似文献   

7.
On the basis of studies on water and land resources affecting urban development and urban system structure in Xinjiang, this paper analyzes the utilization status and shortage of urban water resources. It is considered that both the consumption and waste of urban water resources are in an increase trend. Most cities and towns in Xinjiang are in shortage of water resources, however, waste of water resources are serious, especially in small towns. The development of the megapolis and moderate cities is evidently restricted by limited land resources. Though there are relatively large spaces of expanding the small cities and towns, the output benefits of water and land resources are low. In order to achieve the ordinal expansion of urban system structure in Xinjiang, it is suggested to take the urban spatial development pattern of "one circle and three belts" and the resources-economized strategy in the rapid development of urbanization.  相似文献   

8.
Groundwater has been a major natural resource for human consumption in north China. It is necessary to appreciate the suitability of deep groundwater for drinking, agricultural irrigation, and industrial uses in this region. To this end, a total of 47 groundwater samples were collected from the study area; by comparing the concentrations of different hydrochemical variables with quality standard values, the variable fuzzy set (VFS) was applied to calculate the groundwater quality index (GQI) for various purposes, respectively. Afterward GQI spatial distribution maps were constructed using a geographic information system (GIS) tool to delineate spatial variations of groundwater quality. In this case study, the GQI spatial distribution maps reveal that the areas covered by "Maximum Permissible" groundwater for varying purposes (drinking, irrigation, and industrial) is 1377.2; 2354.7; and 3854.8 km2, respectively. The groundwater in the eastern part of the study area is suitable for drinking, with the southwestern region as the irrigation water source; the entire study area is acceptable for use in industrial, except the western part of Jiaozuo City. Therefore, the GQI spatial distribution maps can provide useful information for non-technical decision makers for better sustainable groundwater resources management.  相似文献   

9.
Acephenanthrylene and aceanthrylene in aromatic fraction of aerosols were identified by means of online hydrogenation gas chromatography mass spectrometry(GCMS). Compared aerosols from vari-ous sources, acephenanthrylene and aceanthrylene were ubiquitously present in urban aerosol. High concentration of acephenanthrylene and aceanthrylene were found in agricultural biomass and coal combustion particles. However, it is difficult to detect in exhaust from gasoline and diesel engine, dustfall, waste water, soil, and sediment. Combustion emissions were considered the major source of acephenanthrylene and aceanthrylene, which can be used as a potential molecular marker for the source pollution in urban aerosols.  相似文献   

10.
Vendors‘Evaluating and Selecting is one study focu s in SCM and VMO. It is one of the very important operations management and can ad vance to implement the strategic aims. With the increase in use of total quality management and just-in-time concepts by a wide range of firms, the vendor sel ection question has become extremely important. It is necessary for firms to tak e part in the global competition and global manufacture. There are some decision -making techniques which can be used for evaluating and...  相似文献   

11.
The assessment of water security is an important content in the security management of water resources due to the fact that the state of water security directly affects both the sustainable development of regional economy and the improvement on the living quality of mankind. Grey associative analysis is introduced and applied to assessment of water security on the basis of grey characteristics of the assessment index system of water security. As a case study shows, grey associative analysis is used for evaluating water security of some provinces in China, and the satisfactory assessment results are obtained. The sequence of provinces in China with regard to water security from good to poor is obtained and, moreover, the water security level of each region is also confirmed. The results obtained accord with the actual state of each region. They are of practical significance and can be used to guide the management of regional water security and a sustainable development of the economy therein. At the same time, the results demonstrate that grey associative analysis provides a new method for assessing water security  相似文献   

12.
The shortage of water supply and the increasingdemand for water resources is a severe problem, andthe optimal allocation is the key to solving this prob lem in management of water resources. It is very dif ficult to solve the large scale discrete problem of waterresources programming because of the intricate rela tion between resources and environment. Combina tion exploding exists in traditional programmingmethods, such as enumerative and dynamic program ming methods. People are …  相似文献   

13.
For drinking water security the German waterworks proceed on a comprehensive concept, i.e., the protection of all the regions from the recharge area to the client. It includes the protection of the recharge area by a precautionary management, a safe water treatment, a strict maintenance of the water distribution network, continuous control and an intensive training of staff. Groundwater protection zones together with effective regulations and control play a very important role. Three protection zones with different restrictions in land-use are distinguished. Water in reservoirs and lakes is also protected by Surface Water Protection Zones. Within the surrounding area the land-use is controlled, too. Special treatment is necessary if acidification happens caused by acid rain, or eutrophication caused by the inflow of sewage. Very important is the collaboration between waterworks and the farmers cultivating land in the recharge area in order to execute water-protecting ecological farming with the aim to reduce the application of fertilizers and plant protection agents. Probable financial losses have to be compensated by the waterworks.  相似文献   

14.
An internet-based information and monitoring platform for the specific requirements of geotechnical engineering projects is presented. The platform is based on a hybrid-model approach consisting of a model-based information management system and a resource management system, the latter also referred to as DCMS. Project key information can be accessed via the main user interface, the "graphical navigator". The graphical navigator provides also a direct access to additional information in the DCMS. Prompt reac-tion in exceptional situations as well as in daily work gets an extensive support. In practical applications it has been proven that this platform seems to be an adequate tool especially for risk assessment and management in geotechnical engineering projects. Components and advantages of the platform as well as ex periences from the applications are presented and discussed in the paper.  相似文献   

15.
Environmental protection is directly related to the sus- tainable development of the economy and society. Controlling the release of major air and water pollutants remains a daunting challenge in China. The removal of major air pollutants [PM, SO2, NOx, volatile organic compounds (VOCs), and Hg] from stationary and mobile sources is becoming increasingly urgent to improve air quality. Additionally, the removal of numerous industrial and natural chemical compounds from contaminated water systems is essential to maintaining the availability of clean water. Therefore, cost-effective and appropriate air pollution control and water treatment technologies must be explored and implemented. Regarding air pollution control, the selective catalytic reduction of NOx (SCR) by ammonia and hydrocarbons over metal oxide and zeolite catalysts is discussed; non-toxic transition metal oxides supported on titania and zeolite matrices are emerging new catalysts.  相似文献   

16.
胡文发 《清华大学学报》2008,13(Z1):151-157
In order to increase the productivity of construction industry, emerging technologies have been constantly introduced and applied in this traditional industry by pilot researchers. This paper provides an integrated model of radio-frequency identification (RFID) and four-dimensional Computer-Aided Design (4D CAD) in construction management. RFID involves the use of tags that collect data and transmit data. RFID can collect data by radio waves instead of light waves. RFID technology is surpassing barcode technology where light waves are easily blocked and barcode labels are easy to fall off or become unreadable due to dust, dirt, or other contaminants. 4D CAD which involves 3D construction models and construction schedules presents visualized construction process. Integration of RFID and 4D CAD in this paper built a dynamic construction management and control system which would reduce the time of capturing data on site and control quality of construction materials efficiently. Pilot test result shows that a construction manager can easily understand how and what a complicated construction project will be accomplished. Although further analysis is necessary, RFID and 4D CAD show promises of being a beneficial technology in construction management.  相似文献   

17.
The water shortage problem in the Haihe River Basin is the most severe in China, and has restricted its economic development. Over-extraction of groundwater has been very severe in the past 30 years. To solve this problem, scientific decisions should be made from a historical perspective. It is important to describe water cycle evolution in the Haihe River basin over the past 10000 years. Datasets of paleoclimate, paleogeography, palynoflora, historical record, isotopic abundance ratio and content were collected for research on different time scales. Some interesting conclusions were drawn by a comprehensive analysis method. First, radiation was the intrinsic force driving the evolution of water cycle. Generally, precipitation increased with temperature. Second, precipitation was high during 8 ka-5 ka B.P., the so-called Yangshao warm period of the Middle Holocene, which recharged the major part of the Quaternary groundwater. Third, heavy floods during this period transported sediment to the seaside, forming the Coastal Plain where cities such as Tianjin, Huanghua, Cangzhou are now located. In the last 3000 years, intermittent moderate floods did not have enough energy to transport sediment to the sea. Rivers usually overflowed in the piedmont region of the Taihang Mountains, and sediment deposited there formed the Piedmont Plain, where locate Shijiazhuang, Xingtai, Handan, Baoding and other cities. Precipitation had a high correlation with temperature in Haihe River Basin in the past 10000 years: the high temperature usually coupled with high precipitation. Today precipitation in the Haihe River Basin is relatively low, owing to low temperature. This study reveals the relationship between temperature, precipitation and river networks in the past 10000 years in Haihe River Basin, which has great scientific and practical importance in understanding the current water circulation and water shortage.  相似文献   

18.
An adaptive fuzzy logic controller (AFC) is presented for the signal control of the urban traffic network. The AFC is composed of the signal control system-oriented control level and the signal controller-oriented fuzzy rules regulation level. The control level decides the signal timings in an intersection with a fuzzy logic controller. The regulation level optimizes the fuzzy rules by the Adaptive Rule Module in AFC according to both the system performance index in current control period and the traffic flows in the last one. Consequently the system performances are improved. A weight coefficient controller (WCC) is also developed to describe the interactions of traffic flow among the adjacent intersections. So the AFC combined with the WCC can be applied in a road network for signal timings. Simulations of the AFC on a real traffic scenario have been conducted. Simulation results indicate that the adaptive controller for traffic control shows better performance than the actuated one.  相似文献   

19.
This paper presents a software simulator applicable to multipath fading channels in urban environments of mobile communication networks. The simulator is constructed by a two-state Markov model and several statistical models for simulating the characterizations of different environments. A core idea of the simulator is to construct a Rice distribution-based multipath fading module produced by a modified Gans Doppler power spectrum,and in combination with a Markov model to predict the time-dependent characteristics of packet in different radio circumstances. It can simply predict the packet performance of the future channel and evaluate the relations between the radio channel and the modulation schemes,error control protocols and channel coding. Simulation results demonstrate that it is a reliable and efficient method.  相似文献   

20.
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