瓦斯在石门揭构造软煤诱发煤与瓦斯突出中的作用

为了更好地认识和防治煤与瓦斯突出,利用扫描电子显微镜和静态液氮吸附仪研究一种构造软煤的微孔结构特征,同时利用自主搭建的大型石门揭煤相似模拟试验系统,研究石门揭露构造软煤过程中瓦斯压力的变化规律。在试验研究的基础上,分析构造软煤的微孔特性对瓦斯赋存的影响,以及瓦斯在石门揭露构造软煤诱发煤与瓦斯突出中的作用。通过试验得出:构造软煤的结构破坏严重,微孔发育并且为特殊瓶颈的不透气孔,为瓦斯的赋存提供了极为有利的条件;瓦斯在突出的启动和发展过程中起重要作用,即在瓦斯压力突然降低、释放膨胀潜能时,瓦斯压力作为动力来源,加速了煤体向采掘空间抛出的过程。     

Fault propagation behavior study and root cause reasoning with dynamic Bayesian network based framework

The Bhopal disaster was a gas leak incident in India, considered the world's worst industrial disaster happened around process facilities. Nowadays the process facilities in petrochemical industries have becoming increasingly large and automatic. There are many risk factors with complex relationships among them. Unfortunately, some operators have poor access to abnormal situation management experience due to the lack of knowledge. However these interdependencies are seldom accounted for in current risk and safety analyses, which also belonged to the main factor causing Bhopal tragedy. Fault propagation behavior of process system is studied in this paper, and a dynamic Bayesian network based framework for root cause reasoning is proposed to deal with abnormal situation. It will help operators to fully understand the relationships among all the risk factors, identify the causes that lead to the abnormal situations, and consider all available safety measures to cope with the situation. Examples from a case study for process facilities are included to illustrate the effectiveness of the proposed approach. It also provides a method to help us do things better in the future and to make sure that another such terrible accident never happens again.     

四溴双酚A和三溴苯酚对大型溞的急性和慢性毒性

为了明确四溴双酚A和三溴苯酚两种溴系阻燃剂对水生生物的生态危害,测定对比了四溴双酚A和三溴苯酚对大型溞的急性毒性(48h-LC50,48 h半数致死浓度)和慢性毒性(包括21 d繁殖量、内禀增长率、净生殖率毒性影响的EC5(5%效应浓度)或NOEC(最高无效应浓度)等),在此基础上采用评估因子法外推四溴双酚A和三溴苯酚的预测无效应浓度(PNEC).毒性测试结果表明,四溴双酚A和三溴苯酚对大型溞21 d敏感繁殖毒性终点EC5(内禀增长率、净生殖率)均比48 h急性毒性LC50低2个数量级,且低于其对繁殖量毒性影响的NOEC.危害评估结果显示,三溴苯酚和四溴双酚A基于慢性毒性的PNEC低于基于急性毒性的PNEC.以繁殖量、内禀增长率和净生殖率毒性危害的EC5值作为大型溞繁殖毒性指标可能比NOEC更能敏感地表征化学品对溞类的危害,四溴双酚A和三溴苯酚对大型溞的慢性繁殖毒性作用相比急性毒性作用更应引起关注,采用以慢性毒性数据为基础的危害评估结果可以较好地保护物种的安全.     

Interactions in hazard management policies: the case of drought in Nicaragua, 1976–2010

The literature on adaptive and multi‐level governance calls for interactive hazard management to increase societies’ resilience. This paper maps the hazard management policies in a poor and hazard‐prone country—Nicaragua—and examines what role the government gives to interactions among different actors at different societal levels. A new analytical framework is developed that includes scope and direction to capture unidirectional or mutual interactions that are either horizontal or vertical. This enables a more complex analysis of interactions than that found in previous research. The review shows that the historical change in the role given to interactions, as a result of a focus on short‐term emergency response being complemented by long‐term risk management, mainly lies in how they are characterised—with more participants and other types of content categories—and the awareness that interactions other than mutual ones can be positive. This illustrates the complexity of the issue of interactions.     

临水河表层沉积物中的重金属污染评价

选取临水河底部表层沉积物为研究对象,采用地质累积指数、潜在生态危害指数对其重金属污染进行评价。结果表明:沉积物Cr、Cd、Cu、Pb的含量介于203.971~412.363 mg/kg,浓度由高到低依次为Cr>Cu>Pb>Cd;Cd、Cu、Pb的空间变异系数较大,依次为82.8%、65.1%和43.1%,表明这3种重金属可能存在点源污染;Cr的空间变异系数较小,为28.2%,说明该重金属可能存在面源污染。地质累积指数表明:Cd和Cr的污染等级分别为3~5级和1~2级,为中度污染到极强度污染,Cu和Pb无污染。潜在生态危害指数RI值为280.54~879.27,污染程度为中等污染至很强污染。Cd为河流表层沉积物重金属污染的最大贡献者。     

雷电电磁脉冲对便携计算机终端的损伤分析

目的使用电磁仿真软件XFDTD,研究雷电磁脉冲(LEMP)对便携计算机的电磁危害。方法给出腔体内部采样点处的电场时域波形图和截面的电场分布图,计算腔体内不同位置处的屏蔽效能和瞬时坡印廷矢量的大小,分析雷电电磁脉冲与腔体正面孔阵和侧面孔洞的耦合以及孔洞的互耦合。结果雷电电磁脉冲会与入射正面和侧面上的小孔发生不同程度的耦合。雷电电磁脉冲对腔体内部的电磁危害很小,电磁能量主要被限制在开孔附近,腔体中心处受到的影响最小。开孔面积越大,耦合进的电磁能量越多。相邻孔洞之间的互耦合效应使得腔体的屏蔽性变差。结论雷电电磁脉冲对便携计算机的危害一般很小。     

危险化学品重大危险源辨识中的问题与对策

危化品企业在根据《危险化学品重大危险源辨识》(GB18218-2009)进行重大危险源辨识的过程中,有四个问题较难解决或处理,即危化品水溶液临界量的确定、重大危险源辨识物质法定范围的确定、部分物质临界量设置不合理、如何确定危险物质的存在量.针对这四个问题提出了相应的对策:对危化品水溶液,其临界量的确定可依据水溶液的主要危害特性,对照《危险化学品重大危险源辨识》(GB18218-2009)中的表2进行确定；对不属于危险化学品,但又具有易燃、易爆、有毒特性的危险物品,如果其数量超过类似危化品的临界量,建议参照危化品重大危险源进行相应的安全管理；对于危险物质临界量的确定,建议按照危险源可能造成的事故危害后果或范围推算确定；对于危化品实际数量的确定,建议按照企业可能存在的最大量或设计量进行计算.     

Climate change beliefs and hazard mitigation behaviors: homeowners and wildfire risk

Downscaled climate models provide projections of how climate change may exacerbate the local impacts of natural hazards. The extent to which people facing exacerbated hazard conditions understand or respond to climate-related changes to local hazards has been largely overlooked. In this article, we examine the relationships among climate change beliefs, environmental beliefs, and hazard mitigation actions in the context of wildfire, a natural hazard projected to be intensified by climate change. We find that survey respondents are situated across a continuum between being ‘believers’ and ‘deniers’ that is multidimensional. Placement on this believer–denier spectrum is related to general environmental attitudes. We fail, however, to find a relationship between climate change beliefs and wildfire risk-reduction actions in general. In contrast, we find a statistically significant positive relationship between level of wildfire risk mitigation and being a climate denier. Further, certain pro-environmental attitudes are found to have a statistically significant negative association with the level of wildfire risk mitigation.     

People's risk perception of glacial lake outburst flooding: a case of Tsho Rolpa Lake,Nepal

Previous research indicates that people's perception of risk from a particular hazard positively influences their adoption of effective mitigation strategies and responses. This research investigates the risk perceptions of people living downstream from Tsho Rolpa Glacial Lake of Nepal. Field surveys revealed that people living beneath the Tsho Rolpa glacial lake possess a low risk perception despite the probability of a glacial lake outburst at their location. Further investigation reveals that many individuals have made no adjustments in response to the potential disaster. The low risk perception on the part of the riverine population is chiefly attributed to the cry-wolf effect of the 1997 evacuation that followed an inaccurate prediction of a Tsho Rolpa outburst. Previous remediation structures were kept in place, but appear to have created a false sense of security among those at risk. This overconfidence in the rudimentary efforts employed thus far is illustrated by the fact that many residents have moved their infrastructure even closer to the river channel in recent years. Partial mitigation efforts have muted people's perceptions of the environmental risk and have therefore increased the vulnerability of the communities to a probable outburst flood.