基于UHBs的输气管道高后果区泄漏燃爆事故分析

为探究输气管道高后果区中人的不安全行为（Unsafe Human Behaviors,UHBs）对输气管道泄漏燃爆事故发生的影响,结合模糊Bow-tie模型和贝叶斯网络对输气管道泄漏燃爆事故进行分析。构建基于T-S模糊故障树的输气管道泄漏燃爆模糊Bow-tie模型,并转化为贝叶斯网络;从人的不安全行为发生的可能性出发,将不同等级高后果区划分为不同等级人口敏感区;利用专家经验评判法得到不同等级人口敏感区基本事件的先验概率和中间事件的条件概率表;运用贝叶斯网络双向推理算法求解模糊Bow-tie模型。结果表明:随着地区人口敏感等级的提高,输气管道泄漏燃爆事故发生的概率随之增大,发现导致输气管道失效泄漏事故发生的最主要原因为施工破坏,失效原因与EGIG分析的结果基本相符,验证该方法在高后果区输气管道泄漏燃爆事故分析上的可行性,可为输气管道高后果区的安全管理提供决策依据。     

A GIS-based technique for linking landscape characteristics to non-point source nitrogen export potential: implications for contributing areas management

A Nitrate-N Leaching Index (NLI) is calculated and the results indicate that nitrogen loss in the study area occurs through both leaching and surface runoff. A non-linear regression model of trapping efficiency was combined with a first order decay model to examine the impact of soil characteristics, slope, vegetative cover, land use and distance to streams on the spatial pattern of non-point source nitrogen inputs to streams. The model evaluates the statistical significance of each landscape factor and provides an easy interpretation of the landscape delivery ratio of nitrogen based on a pixel-based characterisation of the watershed. The model was validated by comparing the distributions of the observed and estimated monthly nitrogen concentrations. The exploratory GIS-based method presented here can improve the understanding of the impact of landscape characteristics on nitrate-nitrogen contributing areas and therefore assist watershed management efforts.     

电力机车司机室的噪声特性研究

研究通过分析电力机车司机室的噪声来源及其特性 ,为改善司机室工作环境提供相关技术资料。以 8K型电力机车为例 ,结合现场测试 ,分析研究了列车在不同运行情况下司机室的主要噪声源及其噪声频谱特性 :常速下 ,呈低频特性 ;通过隧道时 ,频谱特性基本不变 ,但声级增加 ;鸣笛时明显表现风笛的中低频特性。     

TiO2薄膜气相光催化氧化低浓度三氯甲烷和三氯乙烯的研究

自行设计了气固相光催化实验系统,以铝材为担载体,TCM和TCE为模拟污染物,在常温、常压下,对辐射光源、气体相对湿度、污染物反应浓度等因素对TCM和TCE的光催化降解反应的影响进行了研究.结果表明,在研究所采用的实验条件下,辐射光源采用254 nm时的降解效率要比采用365 nm时高10%左右;气体相对湿度为40%时光催化降解效率最高;随着污染物反应浓度的增加,TCM的降解效率降低,而TCE的降解效率增加.初步的反应动力学研究结果表明,TCM和TCE在二氧化钛表面的光催化降解反应可采用Langmuir-Hinshelwood动力学方程来表征.     

美国工业废水预处理制度实施经验及对我国的启示

美国工业废水预处理制度对工业废水间接排放管控成效显著,主要特点包括:明确划分各实施主体的责任,形成全过程有效监管机制;预处理标准以基于技术和基于水质为双重约束;对工业用户实施重点分类管理,细化工业用户合规要求;授权公共污水处理厂直接管控工业用户,提高制度执行效率;注重污染源头控制,鼓励废水和污泥回收利用。对我国启示如下:健全我国工业废水预处理制度体系,强化纳管企业主体责任;在污水处理厂规划设计阶段,开展工业废水来源调查,编制纳管企业名单;在污水处理厂运行管理阶段,开展进水水质跟踪评估,建立污染负荷溯源机制;加大对工业废水间接排放的监督执法力度。     

A river water quality model integrated with a web-based geographic information system

Scientists often use mathematical models to assess river water quality. However, the application of the models in environmental management and risk assessment is quite limited because of the difficulty of preparing input data and interpreting model output. This paper presents a study that links ArcIMS, a Web-based Geographic Information System (GIS) software to ROUT, a national and regional scale river model which evolved from the US Environmental Protection Agency's Water Use Improvement and Impairment Model, to create a WWW-GIS-based river simulation model called GIS-ROUT. GIS-ROUT is used to predict chemical concentrations in perennially flowing rivers throughout the continental United States that receive discharges from more than 10,000 publicly owned wastewater treatment plants (WWTPs). The WWTP chemical loadings are calculated from per capita per day disposal of product ingredients and the population served by each plant. Each WWTP, containing data on treatment type and influent and effluent flows, is spatially associated with a specific receiving river segment. Based on user defined treatment-type removal rates for a particular chemical, an effluent concentration for each WWTP is calculated and used as input to the river model. Over 360,000 km of rivers are modeled, incorporating dilution and first order loss of the chemical in each river segment. The integration of spatial data, GIS, the WWW, and modeling in GIS-ROUT makes it possible to organize and analyze data spatially, and view results on interactive maps as well as tables and distribution charts. The integration allows scientists and managers in different locations to coordinate and share their estimations for environmental exposure and risk assessments.     

国际环境政策研究综述

国际环境政策是环境政策的重要组成部分,对中国的环境治理发挥了积极作用。经过几十年的发展,国际环境政策研究取得了长足发展,由"跟踪""学习"发展和深入到"创新""贡献",由以环境研究相关人员为主发展到全社会广泛关注和参与。另一方面,国际环境政策研究也存在占环境政策研究的比例较低,细分领域分布不平衡、碎片化,综合性战略性研究较少等问题。建议进一步加强国际环境政策的战略研究,加强重点领域的研究,加强基础支撑和条件保障等。     

基于QAR数据的发动机LTO阶段氮氧化物排放量计算与分析

氮氧化物是发动机运行过程中产生的一种主要污染物,对于航空器氮氧化物排放量的准确计算是控制排放和评估其环境影响的基础.本文依据BM2流量修正方法对机载快速存取记录器(QAR)数据中的燃油流量值进行标准化修正,并根据低压转子转速、空地传感器指示、油门杆解算器角度、飞行高度,对起飞着陆循环(LTO)进行更精确的阶段划分.同时,参考国际民航组织公布的特定发动机机型的分阶段排放指数,对PW-4077D发动机某次LTO阶段的氮氧化物排放量进行计算.结果表明,通过精准飞行阶段划分,结合QAR实测数据估算的LTO分阶段(起飞、爬升、进近、慢车)氮氧化物排放量分别达到3415.87、7574.57、3019.98、1721.33 g,与标准LTO估算方法相比,相差30%以上.这种发动机LTO阶段实际排放量的计算方法,可为近地面航空器乃至不同地区整个机场氮氧化物污染评估提供更加准确的依据.     

Developing an integrative urban resilience capacity index for plan making

Urban resilience assessment can help planners understand the status of resilience in an urban system and identify needs for improving resilience capacities. The issues related to urban resilience are complex because of multiple urban system components, threats from different sources, and uncertainty of the future. Urban resilience theories have progressed to consider an urban system as an integrated complex system; however, urban resilience assessments are inconsistent and underdeveloped in assessing an integrated urban system for different threats at various uncertainties. In an effort to address this deficiency, we propose to develop an Integrative Urban Resilience Capacity Index (IURCI) for assessing urban resilience capacity for all threats. To improve the quality of urban resilience assessment, the IURCI considers urban physical form, spatial structure, preparation for future, and performance after plan implementation to measure resilience capacities of absorption, mitigation, and adaptation. It is built in a Scenario-Based Planning Support System (SB-PSS). The SB-PSS is a framework and an open system that integrates IURCI with scenario generation, modeling, and assessment to inform the public, planners, and other stakeholders about the consequences of different planning policies and to assist them make decisions for implementing a preferred scenario.     

China’s three north shelter forest program: cost–benefit analysis and policy implications

Environment, Development and Sustainability - Sandstorms and soil erosion are serious problems around the world, but particularly in arid northern China. In response to these problems, the Chinese...