An imprecise Fault Tree Analysis for the estimation of the Rate of OCcurrence Of Failure (ROCOF)

The paper proposes an imprecise Fault Tree Analysis in order to characterize systems affected by the lack of reliability data. Differently from other research works, the paper introduces a classification of basic events into two categories, namely Initiators and Enablers. Actually, in real industrial systems some events refer to component failures or process parameter deviations from normal operating conditions (Initiators), whereas others refer to the functioning of safety barriers to be activated on demand (Enablers). As a consequence, the output parameter of interest is not the classical probability of occurrence of the top event, but its Rate of OCcurrence (ROCOF) over a stated period of time. In order to characterize the basic events, interval-valued information supplied by experts are properly aggregated and propagated to the top. To this purpose, the Dempster–Shafer Theory of evidence is proposed as a more appropriate mathematical framework than the classical probabilistic one. The proposed methodology, applied to a real industrial scenario, can be considered a helpful tool to support risk managers working in industrial plants.     

Rapid Issue Tracking: A Method for Taking the Pulse of the Public Discussion of Environmental Policy

Environmental communication professionals and other decision makers need to understand public sentiment toward environmental issues to effectively carry out their stewardship responsibilities. However, it is often difficult to obtain timely and reliable information about public discussion and debate regarding these issues. This paper describes an approach designed to address this dilemma: Rapid Issue Tracking is a method for quickly “taking the pulse” of public and other stakeholder discussion. The data source for Rapid Issue Tracking is online media stories, including traditional news media, social media, and other textual data such as public comments received by an agency. Two US Forest Service cases of Rapid Issue Tracking are presented to explicate the method and its usefulness in environmental communication and decision making.     

港湾快速城市化地区河流水质主控因子识别及调控方案

识别快速城市化地区的河流污染的主控因子,对于科学实施河流污染防治调控及实现区域经济又好又快发展具有积极意义。运用流量校准浓度分析法、多元逐步回归分析相结合的方法识别连云港港湾快速城市化地区影响水质变化的主控因子,可准确把握该类区域河流污染趋势及主导原因,进而提出相应的优选调控方案。     

南京市主要湖泊浮游植物群落结构分析

2008年春季,对南京市7个主要湖泊浮游植物及水质进行了调查。结果表明,南京市主要湖泊处于中营养状态到中富营养状态,其中城市湖泊富营养化较为严重,作为饮用水源地的固城湖、金牛湖处于中营养状态,但固城湖浮游植物群落结构表现出富营养化特征。富营养湖泊中出现的种类以硅藻为主,数量以硅藻为主;中营养湖泊中出现的种类以硅藻为多;数量以隐藻、蓝藻为主。各湖泊浮游植物数量与营养状态呈显著正相关。     

自动扶梯的能耗分析及节能控制研究

自动扶梯是一种耗能较大的特种设备。为了贯彻落实国家对高耗能特种设备的监管政策,针对自动扶梯运行特点建立科学可行的能效测试方法和评价标准十分重要。通过介绍自动扶梯运行能耗的检测方法,并对自动扶梯的输入有功功率和乘客流量进行实测。分析了实验结果对自动扶梯能耗的影响因素;探讨了各种节能方法的适用性和有效性。     

基于层次分析法的城市灾害应急管理指标分析

突发事件原生、次生、衍生和耦合灾害,造成城市灾害复杂化和扩大化,给城市应急管理带来重大挑战.基于应急管理体系的层次性、多样性和模糊性特点,分析了我国当前城市应急管理基本要素,运用层次分析法进行综合评价,得出了当前城市灾害应急管理工作重点是制定应急预案、应急管理与协调以及生命线系统恢复三个要素,并提出了相应建议.     

中国暴雨洪涝灾害的统计分析

根据近４０多年来的资料，对我国暴雨洪涝灾害进行了统计分析。分析表明，我国暴雨洪涝灾害面积大，且有随时间而增加的趋势；年均受涝面积最大的地区主要位于江淮流域；暴雨洪涝发生的基本规律，南方早，北方迟，６～８月为暴雨洪涝主要多发期。     

长江重庆段溶解性有机物的荧光特性分析

利用三维荧光光谱(EEMs),并结合平行因子分析(PARAFAC)及主成分分析(PCA),研究了长江重庆段溶解有机物(DOM)的荧光组分特征及其污染来源,并探讨了荧光强度同溶解性有机碳(DOC)及溶解氧(DO)的相关性.结果表明,PARAFAC模型识别出长江重庆段DOM由2类6个荧光组分组成,即类腐殖质荧光组分C1(350/422 nm)、C4(245,305/395 nm)、C5(260,340/420 nm)、C6(260/480 nm)及类蛋白荧光组分C2(275/300 nm)、C3(227,278/329 nm).在DOM来源组成中,陆源的类腐殖质含量占62.56%,类蛋白物质含量占31.31%.类腐殖质组分的荧光强度同DOC的含量存在明显的线性正相关(r=0.73),类蛋白组分的荧光强度同DO的含量呈明显的线性负相关(r=0.80).EEMs-PARAFAC不仅可以表征长江重庆段DOM的光谱特征,示踪长江重庆段的有机污染程度,还可以为三峡库区水体保护提供依据.     

Optimization of the ionization conditions for the trace analysis of PCDD/PCDF with ion trap MS/MS

Commercial ion trap mass spectrometer provides easy-to-operate MS/MS analysis for the determination of PCDD/PCDF. The limit of quantification is appropriately low (0.2 pg for 23478-P5CDF) because all the stages are performed in the trap and sample losses associated with the ion transportation are minimized. However, if excessive ions are injected into the trap, its electrical fields are distorted and an overall reduction in performance arises. Ionization condition is an important parameter as it affects the amount of the total ions produced. If the amount of interfering compounds are negligible, such as standard solution or cleaned-up sample, lower ionization condition (e.g. electron energy: 30 eV, emission current (EC): 150 μA) is preferable. On the contrary, in case excessive interfering ions are coexisting with PCDD/PCDF, such as crude extract or semi-cleaned-up sample, the ionization condition should be high (e.g. electron energy: 90 eV, EC: 350 μA) for the reproductive quantification.