共查询到19条相似文献，搜索用时 359 毫秒
1.
Analysis of a rainwater harvesting system for domestic water supply in Zhoushan, China 总被引：1，自引：0，他引：1
The domestic rainwater harvesting system （DRHS） is an water demands. A computer model has been generated to analyze the important freshwater source for Zhoushan, China to meet performance of the DRHS with different ratios of D/（AR） （water demand/average annual collected runoff） and S/（AR） （storage capacity/average annual collected runoff）. The performance of the DRHS was analyzed by means of the model simulation, which is described by its water shortage rate （WSR） and water loss rate （WLR）. Using the data, a set of dimensionless design calculation chart is introduced. When the water demand and requirement of the design are known, the established chart can be used to easily determine the storage capacity and catchment （roof and other surface） area required to achieve a desired performance level. 相似文献
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It’s widely argued that a business environment of budget control and innovation can be antithetical.This essay explores the ways that management accounting and control practices might enable organizations to achieve both control and innovation in the current globalised economy on a basis of the different views in the management control systems(MCSs) and innovation. 相似文献
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Floods are both risks and resources. Floodwater utilization is an important part of flood management. Considering the rising shortage of water resources, serious water pollution, and undersupply of electric power, it＇s imperative to strengthen flood management. In light of the hydrological characteristics of the Three Gorges Project （TGP） on the Yangtze River in P. R. China, we investigated the necessity and feasibility of TGP floodwater utilization, proprosed dynamic control of limited water level during flood season of the reservoir and basin-wide integrated floodwater management as strategies, and identified problems that might occur in practice. 相似文献
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TIAN Jie ZHANG Xin-fang WANG Tong-yang XIANG Wei Cheng Ming 《重庆大学学报(英文版)》2007,6(4):256-264
This paper introduces a solution to the secure requirement for digital rights management (DRM) by the way of geospacial access control named geospacial access control (GeoAC) in geospacial field. The issues of authorization for geospacial DRM are concentrated on. To geospacial DRM, one aspect is the declaration and enforcement of access rights, based on geographic aspects. To the approbation of digital geographic content, it is important to adopt online access to geodata through a spacial data infrastructure (SDI). This results in the interoperability requirements on three different levels: data model level, service level and access control level. The interaction between the data model and service level can be obtained by criterions of the open geospacial consortium (OGC), and the interaction of the access control level may be reached by declaring and enforcing access restrictions in GeoAC. Then an archetype enforcement based on GeoAC is elucidated. As one aspect of performing usage rights, the execution of access restrictions as an extension to a regular SDI is illuminated. 相似文献
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The Huai River Basin is a unique area in P. R. China with the highest densities of population and water projects. It is also subject to the most serious water pollution. We proposed a distributional SWAT （Soil and Water Assessment Tool） model coupled with a water quality-quantity balance model to evaluate dam impacts on river flow regimes and water quality in the middle and upper reaches of the Huai River Basin. We calibrated and validated the SWAT model with data from 29 selected cross-sections in four typical years （1971, 1981, 1991 and 1999） and used scenario analysis to compensate for the unavailability of historical data regarding uninterrupted river flows before dam and floodgate construction, a problem of prediction for ungauged basins. The results indicate that dam and floodgate operations tended to reduce runoff, decrease peak value and shift peaking time. The contribution of water projects to river water quality deterioration in the concerned river system was between 0 to 40%, while pollutant discharge contributed to 60% to 100% of the water pollution. Pollution control should therefore be the key to the water quality rehabilitation in the Huai River Basin. 相似文献
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Submarine hydrothermal vents occur over a wide depth range from a few meters to several thousands of meters. Most existing hydrothermal fluid samplers are focused on deep-sea environments and are not suited for collecting shallow-water fluids. In this study, a new gas-tight sampler which can be easily deployed by both submersibles and scuba divers to collect fluid samples from both deep-sea and shallow-water hydrothermal vents is presented. The proposed sampler uses an electric control sampling valve for fluid collection and a system to measure and display the temperature of the hydrothermal fluid while sampling. It is capable of working in manual mode to be controlled via external signals, or in automatic mode to collect a fluid sample according to the temperature. The master-slave architecture of the electronic system makes the sampler flexible in meeting many different deployment requirements. The performance of the sampler has been demonstrated by preliminary field tests at a shallow-water hydrothermal vent site. 相似文献
7.
Geographic information systems(GIS)are a widely used tool in urban planning and management.More and more cities and deecision-makers require its attributes of promptness,precision and visualization.But the application of GIS in urban environmental management is still a new field and relevant researches are getting on tardily.As a subsystem of GIS,an urban environmental management geographic information system(UEMGIS0should be a complex multi-discipline and multi-objective tool to perform quantitative multi-dimension analysis and to transfer the results into an expression legible to an ordinary user.It should be a dynamic system of prompt functions based on upgradable databases,and be composed of many subsystems respectively specialized in items about water,air,waste and noise as well as relative standards and regulations.However, existing UEMGISs mostly rely on the basic GIS too much to design the actual requirements of applications and managements in themselves,and the unavailability of sufficient fundamental data has retarded their improvement.In the design of a UEMGIS,the standardization of data classification should be taken into consideration to make the data exchangeable and shareable among its subsystems and within every subsystemj,and the applicable error limits for input data should be defined in accordance with the user s required precision of data out.Data acquisition can be easy and quick if remote sensing,global positioning system(GPS)and other technologies are combined with GIS,Rapidly progressing information fechnologies have been giving a bright prospect for the melioration of UEMGIS that will have great potential and wide application in environmental conservation. 相似文献
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Traffic monitoring is of major importance for enforcing traffic management policies. To accomplish this task, the detection of vehicle can be achieved by exploiting image analysis techniques. In this paper, a solution is presented to obtain various traffic parameters through vehicular video detection system( VVDS). VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time. This algorithm uses the background differencing method, and vehicles can be detected through luminance difference of pixels between background image and current image. Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy. Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process fourchannel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP‘s high performance. In the end, VVDS is tested on realworld scenes and experiment results show that the system is both fast and robust to the surveillance of transportation. 相似文献
9.
ZHANGSiping 《重庆大学学报(英文版)》2002,1(1):77-83
Chinese universities are facing a series of challenges in their accommodations,of which a pr\edominant one is how to provide both students and staff with enough accommodations of a large scope and good quality in good time and with limited budgets,In order to find applicable approaches to solve this problem,the current situations of the Chinese higher education reform and the resulted rapid growth of student numbers whereby the requirement of lodgings is greatly incresed are discussed.It is elucidated that in providing enough accommodations for staff and students,Chinese universities are confronted with difficulties including demand too big,lack of funding support,time limitation and incapability in both project management and facilities management.Industrialized building approach is demonstrated to be a desirable access to build large quantities of accommodations of good quality in limited time.and Private Fuinancial Initiative(PFI) appears to be a prosperous solution to the fund shortage,Regarding project and facilities management,qualified professionals are available by either employing exterior consultants or training related staff of universities for such occupations. 相似文献
10.
Nancy Chitera 《美中教育评论》2014,(12):861-872
The purpose of this article is to develop a framework that can be used to describe and explain how mathematics teachers construct a multilingual classroom and the discourse practices being produced in a mathematics classroom. It conceptualizes the discourse practices used by mathematics teacher educators as they prepare student teachers to teach mathematics. The framework developed here is shaped by Critical Discourse Analysis （CDA） drawn from Fairclough. This provides the theoretical and conceptual tools to examine the discourse practices of mathematics teacher educators and how the）＇ make available these discourse practices for student teachers to draw on. In broad terms, this article examines the discourse practices of the mathematics teacher educators and how they support the student teachers develop discourse practices relevant for teaching and learning school mathematics in multilingual classrooms. This article is broken down into several sections. The first section discusses what it means for student teachers to develop discourse practices for mathematics teaching. The second section provides an introduction to CDA, followed by its origins, key terms, and elements of Fairclough＇s CDA. Thereafter, the author outlines the strategies involved in doing CDA. The last section discusses why CDA is relevant to the mathematics classroom. 相似文献
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从目前国内外雨水利用情况及台州实际情况来看,雨水利用在台州有实行的必要,主要体现在缓解降雨带来的污染、补充城市的水资源问题以及减少城市的洪灾三个方面。针对台州具体情况,从住宅区、城市道路及大型雨水集蓄系统三级蓄水工程出发,进一步探讨雨水利用技术。权衡利弊,对雨水利用在台州水环境中作用加以探索。 相似文献
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雨水是轻度污染水，经简单处理可用于生活杂用水、工业用水。雨水资源化是解决水资源短缺的有效措施之一。本文简述了城市雨水资源化的概念及其内涵。提出了实现城市雨水资源化的基本途径，为城市进行雨水的高效利用提供了依据。 相似文献
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详细介绍了墨西哥哈利斯科州特拉凯帕凯市住宅开发区雨水收集系统的一种家庭模式.为了设计出一个可以为家庭提供最大水量的雨水收集系统,对雨水收集量进行了估算.基于估算出的雨水收集量,对家庭总需水量进行了计算,以便探讨雨水的可能用途.雨水收集系统的主要组成部分如下:集水区;落水管(屋顶排水管),第一冲洗水箱;水箱;渗井;泵站,过滤系统;紫外(UV)处理设备.雨水收集系统被设计成中央供水系统的一部分.介绍了雨水收集系统的设计和建设过程及其造价.通过该方式,可提供一个技术参考,从而帮助市民来设计和建设他们的雨水系统.该模式既可促进此系统在墨西哥的发展,也可为国际社会提供宝贵的经验. 相似文献
14.
安阳市城市雨水综合利用规划研究 总被引：5，自引：0，他引：5
以新的思路和可持续发展的观点,引入雨水资源化的概念.提出安阳市雨水综合利用模式,变雨水排放为雨水生态循环和再利用,解决了因城市发展带来的雨水径流增加、防洪排涝设施的经济投入逐年加大同城市水资源日渐紧张的矛盾.雨水的综合利用对消除城市热岛、减小地下水漏斗区,改善城市自然、生态、大气环境有积极作用. 相似文献
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介绍了非洲东部和南部雨水管网系统中雨水回用的实践与经验,并介绍了在Sub-Saharan Africa开展的雨水回用工程实践情况,包括国家政策的调研、回用理念的构建、雨水系统的建设和回用技术的评估.雨水回用技术在非洲东南部地区被大力推广,并被普遍接受,应用于生活用水及农业用水的补充以及环境可持续发展建设的各个方面.截止目前,已有12个国家级的雨水回用机构建成,他们为雨水回用系统的建设提供整体规划和技术指导.政府和投资商也逐渐转变态度,为推进雨水回用技术在经济、制度和技术上提供了优惠政策.合理的土地与水体管理是雨水资源利用最大化的关键.除了政策和制度的协调外,还需要充足的预算支持来推动技术的广泛应用. 相似文献
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通过浙江大学西溪校区东一教学楼改造的雨水收集工程实践,分析了本地的气象资料、回用水使用与降水时段调节等,将房间空调器凝结水与饮用水反渗透浓水予以收集归入整个雨水收集系统,用于教学楼周围的绿化浇灌与景观水的补水.通过计算,教学楼夏季空调器凝结水量约为3.48 m3/d,每日饮用水反渗透浓水的水量可达到198~396 L.在气温较高的夏季能有效地补充因大量蒸发导致绿化浇灌及景观补水不足的缺陷,同时在降雨量较少的冬季也能一定程度上进行添补.雨水与冷凝水以及反渗透浓水一同收集大大提高了整个收集系统的经济性.项目实测数据验证了系统的经济合理性. 相似文献
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提出了一套基于低影响开发理念的城市雨水综合管理规划方案.与传统排水规划不同,该方案通过在社区尺度上规划各类低影响开发设施,削减径流总量和污染负荷,实现可持续的城市雨水综合管理.采用结合了传统排水管道和低影响开发设施的水力模型,对规划效果进行了评价.通过20年降雨数据的连续模拟发现,在规划完全实施基础上,相对于不采用低影响开发设施,径流总量削减率可达80%以上.为保障和指导规划的实施,结合当地条件,制定了技术实施导则.规划区域内3条主干道道旁生物滞留设施已完成施工建设,区域内其他地块的开发也正在实施导则的指导下逐步开展和实施.提出的基于低影响开发理念的区域雨水综合管理规划、评价和实施方法,将为我国其他地区的类似项目提供经验和借鉴. 相似文献