Using a system theory based method (STAMP) for hazard analysis in process industry

Different hazard analysis techniques are used in the chemical process industry. Most of these techniques were developed long time ago. There is an argument that significant changes have occurred in the process industry but these techniques have not been modified accordingly. Therefore, there may be limitations in identifying hazards related to the modern process industry in complex sociotechnical environment using these techniques. Recently new hazard analysis techniques based on systems theory have been introduced. STPA (System-Theoretic Process Analysis) is one of these systemic techniques. It has been used in some fields with promising results but with limited application in the process industry. This paper applies STPA to a process plant as an industrial case study. Recommendations generated by STPA are compared with the HAZOP study of the process plant which is a traditional technique. Conclusions are presented on the application of systemic techniques to the process industry as a complementary study to analyze the safety of the system as a whole and also to capture interactions between component of the system. Further studies are required to study STPA in more details and evaluate if it can be used as an alternative to HAZOP.     

Mercury in sediment and fish from North Mississippi Lakes

Sediments and/or fish were collected from Sardis, Enid and Grenada Lakes, which are located in three different watersheds in North Mississippi, in order to assess mercury contamination. The mean total mercury concentration in sediments from Enid Lake in 1997 was 0.154 mg Hg/kg, while 1998 sediment concentrations in Sardis, Enid and Grenada Lakes were 0.112, 0.088 and 0.133 mg Hg/kg, respectively. Sediment mercury concentrations in 1999 were similar in all three lakes but, generally lower than 1998. Mean total mercury concentrations in edible fillets of fish collected from Enid Lake in 1998 were above the human health FDA action level (>1.0 mg Hg/kg) for bass (1.40), crappie (1.69) and gar (1.89); however, tissue concentrations were less than 1.0 mg Hg/kg in carp (0.63) and catfish (0.82). Human hazard indexes for each species was 1 for both adults and children, indicating that there is a potential for toxic effects to occur. In addition, calculated consumption limits indicate that adults may consume 4–12 oz. of fish per month, depending on the species consumed. For children, 2 oz. per month may be consumed. Further studies are needed to determine the exact environmental consequences and human health impacts associated with mercury contamination in North Mississippi and the Southeastern United States.     

从广西1994年特大洪灾谈非工程防洪措施

本文根据广西各地１９９４年洪灾的具体情况，深入分析了工程防洪措施的局限性及非工程防洪措施存在的问题，提出了加强广西非工程措施的重点是加强民众水患意识教育，广泛开展洪水多发区的洪水风险评估并加强土地管理，建立先进的洪水预报预警系统及完善的洪水保险业务。     

电炉生产系统工伤事故控制技术的研究

本文是综合应用安全系统工程的原理和方法,控制生产系统的工伤事故,并采用系统辨识理论,辨识生产中的潜在危险和后果,定量评价潜在危险的危害程度和发生概率;综合应用数理统计、工程逻辑、故障树、事件树、管理失误和风险树等多种分析方法,对电炉炼钢生产的原料、冶炼、铸锭、天车、电气、机械等子系统进行了事故发生可能性的预分析和安全状况评价。据分析评价结果,结合生产实际和管理现状,制定了控制事故的综合技术对策,并开发了一系列适合于我国企业安全管理实际需要的计算机软件。     

河南自然灾害现状特点及影响评估

本文主要分析了河南自然灾害的六大特点,并对主要自然灾害进行灰色关联度的分析评价及区域社会经济的影响评价。     

湖南省水灾及减灾研究

本文根据湖南省历史的和现状的水灾资料,对该省水灾状况进行了全面分析,阐述了具体减灾思路,分别论述了该省山区与湖区水灾的减灾问题。     

灾害与经济增长关系的定量分析

本文以哈罗德－多马经济增长模型为基础，初步估计了灾害直接损失对经济增长率的影响。并由此导出了一个计算灾害间接经济损失的方法，为从宏观的角度分析灾害损失与经济增长的关系提供了一种思路。     

环境慢性镉危害早期判断标准的研究──沈阳张士灌区妇女的慢性镉危害

本文根据张士灌区镉的环境污染对居民健康影响的多年研究，提出了镉的内、外暴露水平和对人群肾小管损伤的＂临界值＂以及镉与尿低分子蛋白等多项生化指标的健康效应关系，并通过超＂临界值＂频率和接触归因危险性评价提出了环境慢性镉危害早期判断标准的初步建议．     

藻类爆发危害及其控制技术研究进展

在简要介绍国内外富营养化现状的基础上,阐述了水域中藻类爆发及伴随藻毒素带来的各种危害;分别对水源水控藻除藻技术(限制营养盐控藻、直接除藻灭藻、生物技术与生态工程)和水厂水中控藻除藻技术(预氧化、混凝沉淀、膜滤、直接过滤、气浮、联合处理工艺)的国内外研究现状和应用动态进行了全面评述;指出了各种工艺技术中存在的问题。为今后实现含藻水的标本兼治及有效控藻除藻提供技术借鉴。     

Reasonableness of a proposed System Theoretic Process Analysis (STPA) validation framework: An interview study

Since its inception, the STPA technique has gained increasing popularity among researchers and industry practitioners. Nevertheless, the validity of its application has not yet received much scientific attention. Although some informal validation approaches have been used by STPA users, no formalized validation framework has been elaborated for practical use. This paper investigates the reasonableness of the recently proposed STPA validation framework, which includes 15 validation tests, each focusing on a specific step of an STPA analysis. To do so, STPA experts in both academia and industry were interviewed. First, it is investigated what approaches they have been using for validating an STPA analysis, the findings of which were categorized and mapped with the proposed validation framework. This aims to investigate the similarities and dissimilarities between the theory-based validation framework and the informal methods applied by experts in current practice. Then, the proposed framework was presented to the interviewees to seek their judgments about its reasonableness. Feedback from practitioners indicated that the proposed STPA validation framework has certain strengths, while several opportunities exist for further improvement. In particular, the findings indicate that most of the proposed theory-based tests have been already used by STPA experts in an unstructured manner. The experts appreciated the framework in that it provides clear guidance on how to validate each step of an STPA analysis systematically, and found some additional theory-based tests interesting for consideration in practice. The results also suggest that further research is needed to develop systematic techniques for performing each test to facilitate its application by STPA experts.