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41.
G. J. Kelnhofer 《Journal of the American Water Resources Association》1978,14(6):1423-1428
ABSTRACT: There are many factors, other than economic efficiency, which must be considered in judging the merits of proposed investments in the inland navigation system. No satisfactory formula exists for deciding the net worth of public investments in water resources projects. Such a measure would not be accepted because these investments can serve conflicting goals. Political, rather than technical, judgments are required to resolve these goal conflicts. 相似文献
42.
Ensuring that new buildings do not interfere with the recreational and protective functions of the natural system and that the buildings will be useful long enough to protect the investment are among long-term solutions to coastal erosion. We propose that coastal cliff management districts be established for management of eroding high relief shorelines. Such districts would include an imminent failure zone, in which bluff retreat is possible at any time; a migration zone, which allows for long-term shoreline retreat; and a stability control zone in which activities affecting bluff erosion are restricted. Procedures are described for delineating these zones based on geomorphic criteria. If these land use controls are implemented, some shorefront development can be accommodated while retaining valuable characteristics of the natural system. 相似文献
43.
建筑火灾风险评价体系的建立与应用探讨 总被引:1,自引:2,他引:1
田玉敏 《中国安全科学学报》2008,18(8)
探讨基于安全系统工程思想的建筑火灾风险评价指标体系的建立方法,并在该基础上,通过专家打分和层次分析法,计算得出各指标因子的权重值。根据有关标准和规范,对各评价指标因子进行等级划分,并设计出建筑火灾风险综合分值评分表,为厘定火灾保险费率提供依据。笔者的研究成果为完善建筑火灾风险评价方法、制定财产保险火灾风险评价标准等提供了科学依据。 相似文献
44.
为评估昆明市计划首批建设二环路内16座合流污水调蓄池(规模为21.3×104 m3)的环境效益,采用构建降雨径流管理模型(SWMM)模拟调蓄池的运行情况,对其截污效能进行分析. 结果表明,2008年的113场降雨中,调蓄池共截流污水量1 868.73×104 m3,CODCr、TN、TP污染负荷的截流量分别为5 195.28、810.76、68.78 t,污水截流量占合流污水溢流量的11.18%. 昆明主城调蓄池是在充分利用和衔接已建、在建的排水管网收集系统和污水处理设施的基础上设计的,调蓄池效能受既定配套条件、场地、降雨特征等的多重影响,建议加大调蓄池和污水处理厂的联动性,并采取集中调蓄截流为主、分散式面源治理为辅的策略,综合防治初期雨水径流污染和合流污水溢流污染. 相似文献
45.
Canadian and US marine conservation law, and other related law, was analyzed to determine if it reflected ecological criteria needed to implement connectivity among marine protected areas of the northeast Pacific in the proposed trilateral Baja to Bering Sea (B2B) initiative. The analysis included both nations’ federal laws and those of California, Oregon, Washington, Alaska, and British Columbia. While legal provisions exist already to implement marine protected areas for varying reasons, there is little capacity in most laws to create connectivity among them for conservation purposes. Only California's legislation contained explicit provisions for all the criteria. Other federal, state, and provincial laws, while containing provisions for species at risk and vulnerable habitats, generally lacked explicit provisions for the vital criteria, size of area, migratory patterns, and recruitment patterns. Implementation, future management, and protection of the proposed B2B marine network would be facilitated by amendment of both Canadian and US laws. Some of the ecological criteria are already implied implicitly or vaguely, but they need to be made explicit in the amended law. The legislative model of California could serve as a template for amending the laws of other jurisdictions in the B2B venture. 相似文献
46.
Occupational exposure limits (OELs) developed by authorities play a key role in the implementation of programs to protect workers against hazardous chemicals. Unfortunately, many hazardous substances do not have OELs or the OEL could be outdated. To assure the health of the workers, it is therefore useful for companies to develop corporate OELs. An inhouse strategy will be presented hereafter. Expertise in toxicology, industrial hygiene, and occupational health should be available within the company and clear selection criteria for substances are needed. A corporate OEL is only developed for hazardous substances (e.g., carcinogenic or reprotoxic) with a high potential for worker exposure when an appropriate national OEL or threshold limit value is not available. The methodology to calculate corporate OELs is based on the existing methods for national or community OELs and also on the guidance from the European Union's (EU) regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). For carcinogenic substances with a nonthreshold mode of action, there is always a residual chance that a cancer develops even when the exposure of workers is low. To establish an OEL for these substances, the “German traffic light model” is recommended. It is pragmatic, defines an unacceptable, tolerable, and acceptable risk level when workers are exposed to these substances, and determines risk management for exposure reduction. Overall, the professional practice to develop OELs is a good example of corporate leadership to proactively protect the health of workers. 相似文献
47.
48.
This paper performs a cost-effectiveness analysis of some of the best available technologies (BAT) that can contribute to decreasing the energy consumption and CO2 emissions in the European Union’s (EU27) cement industry. Several capital budgeting decision criteria have been used (the payback period, the net present value and the internal rate of return) to study whether or not an investment should be considered worthwhile. The results show that, independent of the capital budgeting decision criteria used, the number of cost-effective retrofitting possibilities available is large compared to the rate of improvements that the industry undertakes annually. This shows the insensitivity of the industry to financial criteria when it comes to making their investment decisions. The possible thermal energy improvement in the clinker production, if all these BATs were implemented, has been quantified to be around 10%. This achievement would place the cement industry in the upper bound of the benchmark range for clinker manufacture. However considering the delays observed nowadays in terms of diffusion of BATs in the cement industry, it requires a conducive policy environment that combines support for both technology development and to their deployment. 相似文献
49.
辽宁省义县大铁厂地区金钼矿床为浅成中-高温热液石英脉型,受韧性剪切构造和岩浆活动控制。本文在详细研究了矿床地质及地球物理化学特征基础上,总结了该矿床的主要控矿因素并归纳了主要找矿标志,为进一步在该区找矿指明了方向。 相似文献
50.
河口潮汐、盐度、悬浮颗粒物特征因影响化学物质在水体与其他介质之间分配行为,使得咸淡水生物利用度上产生差别,造成咸淡水水质基准标准的差异.重金属如铜,锌,铅,镉和铬等指标由于广泛分布在淡水及海水中,在较高的浓度下可具毒性效应,是现行《地表水环境质量标准》(GB 3838-2002)和《海水水质标准》(GB 3097-1997)常规监测项目.本研究以大辽河口为例,探索这些重金属指标在咸淡水河口区衔接情况和响应规律.首先,基于生物、化学和地质地理相似性确定潮汐界面(TCI)和河海边界(FSI)的位置,划分为潮汐淡水区及混合区.其次,分析了一个潮汐周期内重金属指标的变化特征,以及潮汐淡水区及混合区内盐度和悬浮颗粒物对分配系数Kd的影响,结果表明砷、镉和铬等指标更易受盐度的影响,而锌、铜、铅和镍等指标更易受悬浮颗粒物和潮汐状态的影响.最后,结合潮汐状态和分配系数研究结果,根据这些指标在TCI和FSI的变化趋势,归纳为两类响应规律:第一类如砷、镉和铬等指标,这类指标在FSI具有明显的突变点;第二类如锌、铜、铅和镍等指标,从TCI开始发生变化.两类指标在水相-沉积相-颗粒相介质的分配行为表明颗粒相和沉积相具有相似的变化趋势,尤其颗粒相中的重金属浓度,取决于悬浮颗粒物的浓度,指标响应差异主要存在于水相中.通过本研究识别出易受不同环境因子(如盐度和SS)控制的敏感指标,提出需关注河口本身特征造成的指标背景差异的必要性,将有助于我国现行水质标准制定、修订工作的实施和开展. 相似文献