BLK4-250比例控制器在供水系统设计中的应用

介绍用流量／电流比例控制器取代交流变频调速装置作为高压供水系统的核心部件,通过可编程控制器 (PLC)对工频水泵机组的自动控制作用,消除了由变频器在运行过程中所引发的谐波、喘振、憋压、水锤效应等不利因素的影响,达到了稳定供水压力、节约电能、提高系统可靠性的目的。     

机械设计制造及自动化专业毕业设计的实践及思考

我校2001届机械设计制造及自动化专业毕业设计题型有三种,即软件开发型、理论研究型、设备设计型,对此,学生的兴趣不同,效果也不同.为提高毕业设计质量,需明确该专业毕业设计目的、任务、内容和要求,进行"二阶段式综合训练".     

投资项目中的实物期权及其相互作用

本文首先对投资项目中的实物期权行了分析；在此基础上，从定性和定量的角度研究了实物期权之间的相互作用，并分析了多个实物期权的可加性。     

生态水利工程设计在水利建设中的运用

水资源的合理、科学以及绿色的使用是确保国家高效成长以及保护社会正常运行的前提条件,因此创建生态水利工程具有至关重要的意义。现如今本国的水资源被污染以及浪费的程度愈来愈大,能够将水资源合理、可续的使用起来是水利创建当中最为核心的内容,因此本国的相关单位对于生态水利工程的创建有着极大的重视。针对于此,全文着重探讨了生态水利工程策划的意义、在创建水利工程当中生态水利工程策划需要遵守原则以及生态水利工程在水利创建当中的使用,仅供参考。     

冬季油田压裂供水技术的研究及应用

石油是现代工业的“血液”,是国家生存和发展不可或缺的战略资源,对保障国家经济和社会发展以及国防安全有着不可估量的作用。油田钻井开发工程中的体积压裂技术在低渗透油田的开发中有着显著的增产效果,压裂供水是压裂作业的重要组成部分。我国西北地区冬季气候寒冷,为保障压裂作业在冬季正常开展,冬季的压裂供水研究和应用,对油田钻井开发具有重要的意义。     

浅谈T3连接线项目环水保管理控制

高速公路建设规模大、建设周期长、资源消耗集中,与社会进步、经济发展和环境条件密切关联,对于环境保护和水土保持既有积极作用,又有消极影响。论文主要结合中川机场T3航站楼连接线建设项目环水保管理方面的一些经验和做法,探讨高速公路建设项目环水保在施工阶段的管理控制要素,提出了环水保标准化管理的建议,供高速公路及其他建设项目的环境保护和水土保持管理提供参考。     

An Econometric Estimation of Industrial Water Demand in France

This study investigates the structure of industrial water demand byestimating the derived demand for water on a sample of industrialestablishments located in the south-west of France. Productiontechnologies are represented by short-term variable cost functions andapproximated by a translog form. Industrial water use is modeled ashaving three components: the quantity of water bought to a waterutility, the quantity of autonomous water and the quantity of watertreated prior to use. We include in this framework water effluents,which are considered as a by-product of the production process, emittedby firms. Each of the three water components is treated as a separateinput and all are estimated as a system of simultaneous equations. Themodel is estimated on a sample of 51 industrial plants in the Girondedistrict observed from 1994 to 1996 using Seemingly Unrelated Regression(SUR) and Feasible Generalized Least Squares (FGLS). Results ofestimations show that industrial firms are sensitive to water priceinputs. Network water elasticity is estimated at –0.29. It variesfrom –0.10 to –0.79 according to the type of industryconsidered. Autonomous water price elasticity is not significant.Elasticity for treated water is evaluated at –1.42 at themean-sample and varies from –0.90 to –2.21 according to theindustry considered.     

Post OPA-90 Vessel Oil Transfer Spill Prevention: The Effectiveness of Coast Guard Enforcement

Although oil spills from tanker accidents receive the most publicity, most vessel spills are not the result of accidents but of oil transfer activities. We investigate determinants of the size of vessel oil transfer spills as well as the effectiveness of Coast Guard enforcement activities in reducing their size. Vessel out-of-water and in-water oil transfer spillage functions are estimated utilizing tobit regression and detailed data on individual vessel oil transfer spills as well as Coast Guard safety/environmental enforcement activity data for the 1991–1995 period. Our estimation results suggest that Coast Guard hull but not machinery inspections are effective in reducing both out-of-water and in-water spills; patrols by air, but not by boat, are effective in reducing out-of-water spills; but neither is effective in reducing in-water spills. The results also show that the type of vessel (oil- and non-oil-cargo), vessel characteristics, vessel operations, weather/visibility conditions, and waterway type are determinants of post OPA-90 vessel oil transfer spills.     

博弈论在治理河流水污染中的应用

针对我国日益严重的河流水污染状况，本文通过对污染源企业和政府之间的关系进行博弈分析，建立监督博弈模型，并以此分析政府对污染源企业的监管力度及经济上的处罚力度。     

Evaluating investment projects in the presence of sectoral linkages1

In this paper we develop a framework to assess the economic impact of foreign investment projects. If investment projects interact with other industries in the host economy, either by buying inputs locally or by selling their own product to local downstream firms, they can create sectoral linkages. The expansion of upstream and downstream industries can feed back to the project's own industry leading to a further expansion of the local industry. We study the circumstances under which investment projects lead to the creation of sectoral linkages and characterize the factors that determine the project's welfare impact. We link analytical findings to case studies undertaken for the EBRD.