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保护层分析(LOPA)中的独立保护层探讨 总被引:1,自引:0,他引:1
刘昌华 《安全.健康和环境》2011,11(11):42-45
介绍了保护层分析(LOPA)的基本原理及独立保护层(IPL),讨论过程工业各种典型保护层满足IPL的条件和确定初始事件失效概率(PFD)的原则。在实际运用中,应谨慎识别和确定各种IPL及其PFD,防止IPL虚假使用、重复使用和确定过高或过低的PFD。 相似文献
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水环境的质量关系到个人的健康和国家的可持续发展,是环境领域研究和监测的重要组成部分。数据质量控制是水环境研究中的一个重要问题,其重要性早已受到重视。数理统计可对不同处理间的差异程度以及假设条件进行分析,但无法替代保证数据准确性的计量学方法。文章对我国目前水环境状况及研究进展进行分析,并对环境监测、评价和预警体系中核心内容的数据质量和溯源体系以及测试仪器性能评价进行介绍,从学科发展角度探讨水环境监测和治理对量值溯源和化学计量的需求,为水环境数据质量控制提供计量支持。水环境的发展要求从更大范围的时间和空间尺度对环境问题进行分析,依赖化学计量学手段提供的溯源支持和有效性证明。 相似文献
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依据IEC61508介绍了SIL评估的相关概念和在役装置的SIL评估过程,结合具体评估实例,阐述了回路安全仪表功能(SIF)的安全完整性等级(SIL)定级、SIL验证及平均失效前时间(MTTF)计算,并对计算结果进行了分析。 相似文献
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Policy making at the level of international environmental problems appears to lack a transparent, multi criteria based, decision support ‘tool’. This is due mainly to the highly political, volatile, and contextual nature of issues at this level. The environmental problem of how to regulate emissions from international civil aviation due to their transboundary nature, and the participation of international and domestic players, makes it a ‘wicked’ international environmental problem where policy making has proved problematic. This problem has been used as the basis for developing and pilot testing a tool for contributing to international policymaking, the Multi Criteria Decision Support System (MCDSS). This tool is based on simplifying and integrating key components of Multi Criteria Analysis with a Decision Support System. A preliminary application of the tool explored three options for progressing the reduction of aviation emissions. Testing was based on the allocation of weights to environmental, social, economic and institutional categories, which were each then internally weighted to reflect key criteria in the policy process. Finally, likely performances of each option, against the criteria, were evaluated against Likert scale measures. The outputs from each of these steps were combined to generate a summed best policy option. Conclusions have been drawn and they indicate that the tool is potentially useful especially in the initial stages of policy development. The MCDSS is not an alternative to the international policy process, but rather complements, and makes explicit key tradeoffs in, that process. 相似文献
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此文从失效分析的角度,阐述了模具的基本失效形式及一些主要影响因素.综合讨论了模具设计、制造中应注意的一些问题.尤其应注重对模具失效情况的分析,以利于提高模具寿命,避免早期失效. 相似文献
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Farrell AE 《Environmental monitoring and assessment》2005,107(1-3):59-80
The Montreal Process was formed in 1994 to develop an internationally agreed upon set of criteria and indicators for the conservation and sustainable management of temperate and boreal forests. In response to this initiative, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring (FHM) programs of the United States Department of Agriculture Forest Service have implemented soil measurements as part of a national monitoring program to address specific questions related to the conservation of soil and water resources. Integration of soil assessments into the national FIA program provides for systematic monitoring of soil properties across all forested regions of the U.S. using standardized collection, laboratory, and statistical procedures that are compatible with existing forest inventory data. The resulting information will provide quantitative benchmarks for regional, national, and international reporting on sustainable forest management and enhance our understanding of management effects on soil quality. This paper presents an overview of the FIA soil monitoring program, outlines the field and laboratory protocols as currently implemented, and provides examples of how these data may be used to assess indicators of sustainable management as defined by the Montreal Process. 相似文献