SDG-based HAZOP analysis of operating mistakes for PVC process

As modern chemical plants are becoming more complex and bigger in scale, the associated chance of things going wrong is also increasing rapidly. Due to the flammable, explosive, toxic and corrosive nature of chemical process, any single accident may trigger a major catastrophe that brings tremendous environmental, social and economical loss. In order to prevent any accident from happening, hazard and operability (HAZOP) analysis has been brought in to monitor chemical process and provide early warning for signs of accident. However, most existing HAZOP is carried out manually, and there are always obstacles in terms of cost overrun and incompleteness of the analysis. To address the difficulties in current HAZOP method, this paper proposes a signed digraph (SDG)-based HAZOP analysis method. It is used to identify the most likely operating mistakes that may cause certain process variable deviating from its normal value, which is the main source of safety concern. A case study on polyvinyl chloride (PVC) plant is presented to demonstrate the effectiveness of SDG-based HAZOP analysis method in providing complete analysis result.     

峨眉山5·2崩塌灾害及防治措施

2005年5月2日峨眉山风景名胜区内通往主景点的公路边坡暴发了一次崩塌灾害,崩塌土方量约4 000m3,灾害导致大量旅客滞留,对旅游业造成了一定的损失。5.2公路边坡崩塌灾害不是偶然形成的,而是地质因素、地貌因素、气象因素和人类活动影响因素综合作用的结果;是激发因素——暴雨、开采石灰石挖空山体的不合理经济活动、有利的地质条件——两地层交接部位和地形条件——山高坡陡等综合作用的结果。针对本区的社会条件和自然条件,提出了防灾、减灾对策,具体分为应急处理和远期治理。     

下翼缘摩擦式自定心钢框架梁柱节点抗震性能的数值模拟

介绍了一种新型的钢框架梁柱节点形式,其中预应力钢绞线提供了结构在地震作用下的复位功能(自定心),设置在梁端下翼缘的摩擦件则为结构提供了耗能能力;介绍了下翼缘摩擦式自定心钢框架梁柱节点的构造和工作原理,以节点的低周反复加载试验结果为依据,利用面向对象的开放式计算程序OpenSees建立了节点的数值模型,并侧重于模拟节点在...     

Exploring the effects of population growth on future land use change in the Las Vegas Wash watershed: an integrated approach of geospatial modeling and analytics

The Las Vegas Valley metropolitan area is one of the fastest growing areas in the southwestern United States. The rapid urbanization has presented many environmental challenges. For instance, as population growth and urbanization continue, the supply of sufficient clean water will become a concern. In addition, the area is also experiencing the longest drought in history, and the volume of water storage in Lake Mead, the main fresh water supply for the entire region, has been reduced greatly. The water quality in the main stem of the Las Vegas Wash (LVW) and Lake Mead may also be significantly affected. In order to develop effective sustainable management plans, the very first step is to predict the plausible future urbanization and land use patterns. This paper presents an approach to predict the future land use pattern at the LVW watershed using a Markov cellular automata model. The multi-criteria evaluation was used to couple population density as a variable depicting the driving force of urbanization in the model. Moreover, landscape metrics were used to analyze land use changes in order to better understand the dynamics of urban development in the LVW watershed. The predicted future land use maps for the years 2030 and 2050 show substantial urban development in the area, much of which are located in areas sensitive to source water protections. The results of the analysis provide valuable information for local planners and policy makers, assisting their efforts in constructing alternative sustainable urban development schemes and environmental management strategies.     

Trends of ischemic heart disease mortality attributable to household air pollution during 1990–2019 in China and India: an age-period-cohort analysis

Environmental Science and Pollution Research - Cardiovascular diseases (CVD) caused by household air pollution (HAP) have sparked widespread concern globally in the recent decade. Meanwhile,...     

南京市经济发展与环境污染关系的实证研究

根据南京市1991～2003年经济与环境数据,分析经济发展与环境污染的相互关系,建立了南京市经济增长与环境污染水平的计量模型,进而评价了南京市的环境保护政策。研究表明：作为一个重化工业城市,南京市自20世纪90年代以来,在经济高速发展的情况下,其环境恶化程度逐步得到遏制,部分环境指标与人均GDP演替轨迹呈现显著的环境库兹涅茨曲线特征。这主要归功于南京市政府近年来有效的环境政策和巨额的环境投资。     

REVIEW ON GLOBAL NATURAL DISASTERS IN 2000

20 0 0ｗａｓａｒｅｌａｔｉｖｅｌｙｎｏｒｍａｌｙｅａｒｉｎｔｅｒｍｓｏｆｇｌｏｂａｌｄｉｓａｓｔｅｒｅｖｅｎｔｓ.Ｔｈｅｇｌｏｂａｌｌｏｓｓｆｒｏｍｎａｔｕｒａｌｄｉｓａｓｔｅｒｓｗａｓａｐｐｒｏｘｉｍａｔｅｌｙ 30ｂｉｌｌｉｏｎＵＳＤ ,ｗｈｅｒｅａｓｔｈａｔｉｎａｎｙｏｆｔｈｅｐｒｅｖｉｏｕｓｙｅａｒｓｈａｄｅｘｃｅｅｄｅｄ 1 0 0ｂｉｌｌｉｏｎＵＳＤ .Ｔｈｅｉｎｓｕｒａｎｃｅｌｏｓｓｉｎ 2 0 0 0ｗａｓｏｎｌｙ 8.3ｂｉｌｌｉｏｎＵＳＤ ,ｗｉｔｈ 92 0 0 ｐｅｒｓｏｎｓｋｉｌｌｅｄ .Ｔｈｅｒｅｗａｓｎ…     

电子元件制造行业典型危险废物产生节点及处置建议

电子元件制造行业是国家战略性新兴行业,同时也是高污染的行业,其生产工艺具有更新换代快、中间产物多、排污方式复杂等特点.行业危险废物也具有来源多、成分复杂、产生量大等特点,若未经妥善处置而排放到环境中,会对环境造成巨大的危害.通过对印制电路板、铝电解电容器、半导体器件3类典型电子元件的工艺流程进行梳理,分析典型危险废物的...     

Plasticity in metamorphic traits of <Emphasis Type="Italic">Rana kukunoris</Emphasis> tadpoles: The interactive effects of food level and rearing temperature

Larval amphibians are particularly likely to encounter variation in rearing temperature and resource availability due to variation in aquatic breeding habitats. In this study, plasticity in growth rates, larval mass, larval period, and size at metamorphosis were examined in Rana kukunoris Nikolskii, 1918 under different combinations of temperature and food level. Larval period and larval body mass was sensitive to food level, and varied with temperature. Tadpoles metamorphosed at an older age at low temperature than those reared at warm temperature. Food level was a significant affect on larval period at low temperature, but not at warm temperature. Mass was heavier for tadpoles reared at low temperatures than those reared at warm temperatures. The effect of food level depended on temperature, because larvae reared at low temperature that were offered a high food level achieved a larger size than larvae offered a low food level, but this did not occur at warm temperature. Therefore, we suggest that high food availability at low temperature prolonged developmental periods, thus larvae are larger as metamorphs than those reared at warm temperatures.     

森林消防人员防烟面罩技术探讨及应用

阐述了森林消防防烟面罩的研制及其改进过程,介绍了森林消防防烟面罩的主要技术经济指标及野外应用试验。