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41.
Johann W.N. Tempelhoff 《Physics and Chemistry of the Earth》2009,34(3):164-175
The Vaal River Barrage, situated on the south-eastern border of the Gauteng Province, has been part of the hydrological landscape of South Africa’s most populous and economically active region for more than eight decades. After its completion in 1923 the Barrage was compromised by the construction, upstream, of the Vaal Dam (1930-1933). Today the Vaal River Barrage is primarily a storage facility of sewage and industrial waste water. South Africa’s transition to a multi-racial democracy in 1994 saw a number of socio-economic and political transformations that affected the water infrastructure. In the field of sanitation infrastructure in particular, conditions have deteriorated to the extent that the health of people in many parts of the country is being compromised.Using the Vaal River Barrage as a case study, this article outlines the efforts by civil society to make the relevant government sectors aware of this hazardous state of affairs. particular attention is given to save our Vaal environment (SAVE), a non-governmental organisation, at the helm of an active campaign to reduce pollution in the Vaal River Barrage. 相似文献
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西藏某水电站厂区后山发育了5条泥石流沟,2005年7月22日暴发了近百年来最大的泥石流,泥石流的规模和影响范围将直接影响到该厂房的枢纽布置、施工及运行安全。厂房区泥石流沟的泥石流固体物质来源丰富,形成区内沟道坡度陡峭,因此只要有足够的降雨就可以形成泥石流。以设计泥石流流量计算的泥石流的总径流量确定的泥石流危险范围与调查的厂区各条泥石流沟2005年的实际泛滥区很相近,并以此可以得到不同设计频率的泥石流危险区。电厂厂房区的设施在施工期和运行期间受到泥石流活动的一定影响,必须采取合理的泥石流工程防护措施,避免泥石流对厂房区设施的危害,保障电站的施工和运行,满足电厂厂区的建设需要。 相似文献
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非法演绎作品保护新论 总被引:1,自引:0,他引:1
董慧娟 《广东海洋大学学报》2008,28(2):29-32
总结世界各国立法和我国学者的观点,并结合著作权法的立法价值,提出:非法演绎作品应受著作权法保护,而不宜以民法的不当得利制度进行保护。 相似文献
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Diverted sediment causes a wide range of problems at small diversion works.The difference in water levels between low flows and floods,low investment capital and presence of cohesive sediment and fine non-cohesive sediment coupled with a requirement for a high level of supply assurance makes the design of such hydraulic structures complex.Vortex settling basins(VSBs)offer a promising alternative to conventional settling structures or hydro-cyclones.In the current study,parameters affecting the trapping of particles>75 mm were numerically investigated using ANSYS Fluent and were validated by physical modeling.It was established that the inlet velocity needs to be maintained at 0.26 m/s,the underflow to inflow ratio should be between 0.05 and 0.10,the cylinder height to cylinder diameter ratio should be greater than 0.5,and the positioning of the inlet pipe to cylinder height ratio should be greater than 0.7,with a cone of slope ratio of 2:1(V:H)and the cylinder diameter to inlet diameter ratio should be 8.2.These parameters form the basic design guidelines for VSB use at small diversion works(<100 L/s duty capacity). 相似文献
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黄河河道整治工程险情分析 总被引:8,自引:1,他引:8
分析了黄河河道工程险情发生的原因,重点论述了丁坝附近的水流结构 特征及丁坝主要险情的机理,依据历年来工程出险资料统计分析了现状河道工程险情的特点,即现状河道条件下,河道工程重大险情基本上集中在控导工程一类,从险情的时间分布上、有涨峰阶段,洪峰阶段和落峰阶段,更为严重的是黄河河道工程险情不仅易在大水时期发生、小水时,非讯期也可能发生;在1000-2000m^3/s流量下出险的频率最高,可达到33.7%。 相似文献
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论环境地质工作 总被引:1,自引:0,他引:1
蒋承菘 《水文地质工程地质》2004,31(4):106-110
本文阐述了资源与环境在可持续发展中的作用,指出了资源与环境间互相关联、互相影响的关系,说明了地质作用是资源与环境形成的源泉,从而论证了地质学是可持续发展的重要组成部分。文中详细论述了地质环境与环境地质的内涵,探索了地质环境的自然属性与社会属性,并进而讨论了环境地质学科的分类,文章用“以地质环境为实,以环境地质求真”来反映地质环境与环境地质之间的关系。本文还详细叙述了环境地质工作与地质环境行政管理工作的内涵及其相互之间的关系,指出了地质环境是环境地质工作的对象,环境地质学科是环境地质工作的理论基础。环境地质工作内涵广泛,是一项系统工程,而地质环境行政管理则是一项以环境地质工作为基础、社会公共服务为主体的行政管理工作。文章还提出了做好环境地质工作应给予组织上的保证。 相似文献
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Southsea Looproad at Brymbo suffers large and varied settlements where the highway crosses a smouldering coal refuse bank. A sudden surge in combustion activity during 1991 resulted in considerable subsidence within the carriageway and posed recurring and persistent difficulties for road safety and highway maintenance. Initial investigations involved subsurface temperature measurements to delimit the hot spots and provide a basis for the design of remedial works. The aim of remediation was to extinguish the migrating fire in the outer loop area and to control the burning throughout the remaining areas. The principal strand of the remediation strategy involved excavating the burning coal refuse, cooling, mixing with pulverized fuel ash and compacting. Supplementary containment measures included limestone-filled cut-off trenches, cementitious grout curtains and impervious clay blankets. The works achieved the design objectives, however, small pockets of smouldering material remained within the inner loop. Subsequent monitoring of the site disclosed two markedly different patterns of temperature response on each side of the road. On the outer rim of the looproad temperature trends were steadily downwards in accordance with expectations and indeed reached ambient temperature within about one year. However, on the inside of the looproad seasonal surges in temperature have been recorded during winter months every year since the completion of the remedial works in 1993. The explanation for this unusual pattern of combustion activity is thought to be related to climatic effects and particularly the combined influence of rainfall, atmospheric pressure, air temperature and wind strength and direction. The relative contribution of these factors remains uncertain. Temperature monitoring continues in order to identify the eventual end of combustion activity and determine the appropriate time to complete reinstatement of the carriageway. 相似文献
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