基于事件树的危险化学品污染事故应急技术库构建

近年来我国危险化学品环境污染事故频发,如何及时有效地对污染物进行应急控制及消除显得尤为重要。本文基于事件树分析法原理,根据危险化学品理化性质及其环境污染事故的特征,从污染物种类、污染介质和污染物性质三个方面归纳出危险化学品环境污染事故的42种事故情形,给出每种污染事故情形所对应的处理处置技术方案,构建危险化学品环境污染事故应急处理处置技术树。基于Web服务器Apache、PHP语言和MySQL数据库管理系统开发,建立了危险化学品环境污染事故应急处理处置技术库,实现对技术方案方便快速地查询。     

我国燃煤锅炉汞减排工艺措施探讨

面对当前汞污染日益严峻的趋势,分析了燃煤锅炉烟气其它污染物（如二氧化硫、氮氧化物、颗粒物）控制设施及其运行情况,结合所燃用的煤质情况,介绍了燃煤锅炉烟气汞减排各种经济实用的方法,以及选择汞排放控制措施的“抉择树”。根据燃煤锅炉烟气实际情况,确定可采用的汞减排控制技术,必要时采取活性炭喷射脱汞技术（ACI）,最大限度地提高协同除汞效果。同时提出了应注重燃煤残留物中汞的二次污染问题。     

Fuzzy fault tree analysis for fire and explosion of crude oil tanks

Crude oil tank fire and explosion (COTFE) is the most frequent type of accident in petroleum refineries, oil terminals or storage which often results in human fatality, environment pollution and economic loss. In this paper, with fault tree qualitative analysis technique, various potential causes of the COTFE are identified and a COTFE fault tree is constructed. Conventional fault tree quantitative analysis calculates the occurrence probability of the COTFE using exact probability data of the basic events. However, it is often very difficult to obtain corresponding precise data and information in advance due to insufficient data, changing environment or new components. Fuzzy set theory has been proven to be effective on such uncertain problems. Hence, this article investigates a hybrid approach of fuzzy set theory and fault tree analysis to quantify the COTFE fault tree in fuzzy environment and evaluate the COTFE occurrence probability. Further, importance analysis for the COTFE fault tree, including the Fussell–Vesely importance measure of basic events and the cut sets importance measure, is performed to help identifying the weak links of the crude oil tank system that will provide the most cost-effective mitigation. Also, a case study and analysis is provided to testify the proposed method.     

Application of optimal harvesting decision model to the analysis of Chinese forestry economic policy

This paper firstly extends the single period forest optimal harvesting decision model to infinite periods,in order to indicate how to determine the optimal rotation period aimed at maximizing forest revenue in all directions when repeat planting and harvesting trees on the same plot of earth till infinite future.The study also analyzes the influence of discounted rates,timber price,harvesting costs,planting costs,and tax on the determination of optimal rotation period;and how the optimal rotation period will change when we introduce the factors of continuously rising timber price and ecological revenue.Secondly,the authors introduce the intergenerational equity principle into the above model to design a resource-exploiting mode which satisfies bom the dynamic efficiency principle and the intergenerational equity principle.Last but not least,the research applies the above model to the analysis of Chinese forestry economic policy and explains the economic theory of institutions such as Government Purchasing Ecological Forest,Tree Compensation,and Forestry Subsidization,which provides a necessary theoretical foundation for future application of these new institutions.Besides,in regard to mis theoretical framework,the authors analyze the necessity of the Natural Forest Protection and Grain for Green projects which are currently being implemented in China.We also point out the emphasis of work to insure the project sustainable and successful.Finally,the research discusses the enterprise’s incentive to over-the-quota harvesting and the government’s means of restricting such behavior,which highlights the fact mat improved supervision and higher penalties are helpful in restricting over-the-quota harvesting.     

NEWS

Abstract

Based on the data of urban land use obtained by remote sensing interpretation from aero images in 1986 and 2004, the spatial structure of Jinan is studied in this paper with the method of Geographic Information System (GIS). According to the proportion of land for residence, industry and commerce, the urban district can be distinguished into three rings. Compared with the traditional theory of the ring structure in Western countries, they have many distinctive characteristics. The main functions of the inner ring include residence, business and banking, but the proportion of residential land (more than 50%) is considerably higher than that of the cities in Western countries. The land proportion for residence and industry in the intermediate ring is equal on the whole. The main land of the outside ring is for industrial use. From 1986 to 2004, great changes have taken place on the land proportion of different types of use. In the inner ring, the land for residential and industrial use has shrunk much while the land for commercial use has increased. In the intermediate ring, the changes of the three types of land use were not very much and the temporal variation was relatively stable. On the contrary, the structure in the outside ring varies acutely. Though most of it is also for industrial use, the proportion of residential land has increased much. The three rings can also be divided into several sectors respectively, according to the function of land use clusters. New trends and mechanisms of the changes of land use impacting the urban structure were proposed in the end of the paper.     

Climatic dependence of the Late Holocene dynamics of tree species cenotypes in the intrazonal ecotone of Eastern Sayan forests

A comprehensive study of paleobotanical materials collected in the northern part of the Eastern Sayan was performed, including botanical analysis of peat, palynological and carpological analysis, and radiocarbon dating. The results provided a basis for reconstructing in detail the spatiotemporal distribution of ecocenotic complexes and corresponding paleoclimate types and calculating quantitative gradients of heat and moisture supply in the Late Holocene, beginning from 3500 ka.     

高温气冷堆新燃料运输事故频率分析

商用高温气冷堆核电站是中国未来可能发展的第四代核电站,其新燃料元件和运输容器有显著的特点.探索了将概率安全评价(PSA)方法引入放射性物品运输的辐射风险评价中,首先用故障树方法分析了高温气冷堆新燃料元件公路运输的潜在事故频率,经过事故情景分析、力学分析和临界分析,选择了货包辐射水平升高和临界两种潜在事故予以分析.结果表明,货包辐射水平升高的事故频率很低;临界事故的频率极低,在后续的风险评价中可忽略.     

基于ISM和模糊故障树的铁路黄土隧道塌方风险分析

研究如何对铁路黄土隧道塌方风险事故进行管理控制,先从地质因素、施工方法因素、监控量测因素和施工管理因素分析了黄土隧道塌方事故的成因。接着依据铁路行业隧道风险评估指南矿山法隧道施工风险因素列表,识别影响兰渝铁路某黄土隧道项目塌方的18项主要风险因素。然后运用系统工程解释结构模型方法(ISM)分析项目各风险因素间的相互关系,得出影响该隧道项目塌方的直接原因为施工扰动过大、支护不及时、拱脚悬空时间过长和信息反馈处理不及时。底层原因则为开挖方式、特殊地质条件。在上述基础上建立项目塌方事件模糊故障树模型,进行模糊定量分析,得到项目塌方事件发生的模糊概率和关键风险因素的模糊重要度。结果表明,实例黄土隧道项目塌方事故风险概率很大,地质因素、开挖方法等对塌方事故影响最大。解释结构模型方法能揭示各风险要素间的不确定性因果关系,有利于把握事故发生机理,模糊数能客观地描述风险事件的发生概率,增强故障树诊断方法的可靠性。     

Analyzing injury severity factors at highway railway grade crossing accidents involving vulnerable road users: A comparative study

Objective: The main objective of this study is to identify the main factors associated with injury severity of vulnerable road users (VRUs) involved in accidents at highway railroad grade crossings (HRGCs) using data mining techniques.

Methods: This article applies an ordered probit model, association rules, and classification and regression tree (CART) algorithms to the U.S. Federal Railroad Administration's (FRA) HRGC accident database for the period 2007–2013 to identify VRU injury severity factors at HRGCs.

Results: The results show that train speed is a key factor influencing injury severity. Further analysis illustrated that the presence of illumination does not reduce the severity of accidents for high-speed trains. In addition, there is a greater propensity toward fatal accidents for elderly road users compared to younger individuals. Interestingly, at night, injury accidents involving female road users are more severe compared to those involving males.

Conclusions: The ordered probit model was the primary technique, and CART and association rules act as the supporter and identifier of interactions between variables. All 3 algorithms' results consistently show that the most influential accident factors are train speed, VRU age, and gender. The findings of this research could be applied for identifying high-risk hotspots and developing cost-effective countermeasures targeting VRUs at HRGCs.