基于模糊Petri网的有载分接开关故障诊断方法研究

为解决分接开关故障诊断以主观经验、缺乏系统化流程以及诊断结果与分接开关实际发生故障存在偏差等问题,依据当前分接开关主要故障分类,提出基于模糊Petri网的有载分接开关故障诊断模型,并结合分接开关典型故障案例,验证模型有效性。研究结果表明：基于模糊Petri网的分接开关故障诊断模型能够有效处理故障概率中不确定性因素,具有容错性好、运行效率高等优势,研究结果可为提高分接开关故障诊断的准确性、保障电力系统安全稳定运行提供参考。     

改进组件树在隧道裂缝识别中的应用*

为提高衬砌裂缝病害事故隐患识别率,解决隧道表面普遍存在的对比度低、噪声污染严重、光照不均匀等问题,采用Retinex方法对图像进行噪声抑制和细节增强,结合组件树算法快速建立组件树并剪枝,建立1种新的隧道衬砌裂缝识别算法。研究结果表明:改进后的算法可有效平衡图像光照,保护图像中裂缝边缘信息,识别精度大于95%。研究结果可为识别隧道裂缝引起的安全隐患提供新的方法。     

多因素影响下系统故障预防的多方案比选方法研究

为研究多因素影响下系统遭遇危险事件前预防方案的选优,在集对分析和空间故障树基础上提出比选方法。首先,论述集对分析与空间故障树理论结合的可行性;其次,研究系统故障预防的多因素多方案比选方法和步骤;最后,通过实例进行分析。研究结果表明：停运方案没有因素分量系数影响,其损失是停运带来的经济损失;无措施方案的系统常分量系数最小,因素分量系数最大;采取措施方案中,当常分量系数相差不大时,因素分量系数积最小者为最优方案。使用赵森烽-克勤概率表示危险事件的发生特征是可行的;常分量系数代表方案对系统故障预防效用的可靠性,因素分量系数代表该可靠性的稳定性;结合常分量系数和因素分量系数即可确定最优方案。该方法适合于故障发生对因素变化敏感的系统。     

基于动态贝叶斯网络的石化装置火灾事故动态风险分析

为揭示石油炼化装置事故风险动态特性和事故情景演变路径,在对石化装置进行风险因素分析的基础上构建石化装置火灾事故故障树,基于贝叶斯网络非常规突发事故的演变过程,构建情景演变下的动态贝叶斯网络模型,在综合考虑应急措施的基础上,利用MATLAB软件和联合概率公式计算出各种事故场景的状态概率.以丙烯精馏装置火灾事故为例,结果表...     

最小割集在系统安全分析方法中的应用

利用事故树分析法对矿井火灾进行分析 ,结合平煤六矿建立了矿井火灾事故树。阐述了最小割集理论及其在事故分析中的作用 ,着重提出了对事故树底部事件进行排序分级的加权结构重要度分析法。该方法新颖、简洁而实用 ,为系统安全分析提供了新的方法和途径。     

Applications of fuzzy faulty tree analysis and expert elicitation for evaluation of risks in LPG refuelling station

A method is presented for analysis of reliability of complex engineering systems using information from fault tree analysis and uncertainty/imprecision of data. Fuzzy logic is a mathematical tool to model inaccuracy and uncertainty of the real world and human thinking. The method can address subjective, qualitative, and quantitative uncertainties involving risk analysis. Risk analysis with all the inherent uncertainties is a prime candidate for Fuzzy Logic application. Fuzzy logic combined with expert elicitation is employed in order to deal with vagueness of the data, to effectively generate basic event failure probabilities without reliance on quantitative historical failure data through qualitative data processing.The proposed model is able to quantify the fault tree of LPG refuelling facility in the absence or existence of data. This paper also illustrates the use of importance measures in sensitivity analysis. The result demonstrates that the approach is an apposite for the probabilistic reliability approach when quantitative historical failure data are unavailable. The research results can help professionals to decide whether and where to take preventive or corrective actions and help informed decision-making in the risk management process.     

整地施肥对尾叶桉生长及土壤性状的影响

整地施肥试验结果表明，全垦、带垦和穴垦三种整地方式以及施肥对尾叶按造林成活率和保存率均无明显的影响，成活率在９５％－９８．８％之间，保存率在９２．１％－９７．７％之间．整地能改变土壤性状，如土壤孔隙度全垦为５７．８８％。穴垦为４９．４２％；对林木生长有促进作用，但作用效果很快减少，如造林３年后的林木材积全垦、带垦分别为穴垦的１３６．４％和１２０．０％，５年后却分别下降到１１６．５％和１０８．３％．施肥可提高土壤养分，促进林木生长．造林５年后的调查结果，穴垦施肥林地的土壤有机质、速效Ｎ分别为１５．４４７ｇ／ｋｇ和４９．２３０ｍｇ／ｋｇ，林木年均树高生长为１．２５ｍ；不施肥处理的有机质、速效Ｎ分别为１０．３８８ｇ／ｋｇ和３５．７１５ｍｇ／ｋｇ，林木年平均生长量为０．３５ｍ；林木材积施肥处理的为不施肥的９．８倍．整地施肥还可提高林木叶片的养分含量．     

Genetic and Environmental Effects Assessment in Scots Pine Provenances Planted in Central Siberia

Scots pine provenance trials were established in 1964 in forest-steppe and in 1974 in southern taiga zones of Central Siberia from seeds collected over whole Russia. Tree-ring characteristics (radial growth and density chronologies) from 12 and 16 provenances planted in those plantations were measured densitometrically. Tree-ring analysis revealed a retention of a genetically fixed response to climatic factors proper to pines' origin. Trees from higher latitudes keep the orientation towards accelerated growth at the beginning of a growing season, which is followed by a rapid transition to formation of latewood cells and deceleration of growth earlier, than in medium-latitude trees. Main climatic factors controlling tree-rings formation differed slightly between different provenances within plantations. Genetically fixed ability of the provenances are not great (less than 15%), that proves high adaptability of pines to abrupt climatic change. Tree-ring formation of Scots pine provenances is mainly determined by the environmental factors.     

Dendroremediation of trinitrotoluene (TNT) part 1: Literature overview and research concept

BACKGROUND, AIM AND SCOPE: For decades, very large areas of former military sites have been contaminated diffusely with the persistent nitroaromatic explosive 2,4,6-trinitrotoluene (TNT). The recalcitrance of the environmental hazard TNT is to a great extent due to its particulate soil existence, which leads to slow but continuous leaching processes. Although improper handling during the manufacture of TNT seems to be a problem of the past in developed countries, environmental deposition of TNT and other explosives is still going on unfortunately, resulting from thousands of unexploded ordnance or low order explosions at munitions test areas and at current battlefields. OBJECTIVE: Sustainable phytoremediation strategies for explosives in Germany, which intend to use trees to decontaminate soil and groundwater ('dendroremediation'), have to consider that most of the former German military sites are already covered with woodlands, mainly with conifer stands. Therefore, parallel investigation of the remediation potential is necessary for both of the selected hybrids of fast growing broadleaf trees, which are waiting for planting and forest conifers, which have already proven for decades that they are able to grow on explosive contaminated sites. MAIN FEATURES: A short literature review is given regarding phytoremediation of TNT with herbaceous plants and some general aspects of dendroremediation are discussed. Furthermore, an overview of our TNT-dendroremediation research network is introduced, which has the strategic goal to make dendroremediation more calculable for a series of potent trees for site-adapted in situ application and for the assessment of tree remediation potentials in natural attenuation processes. RESULTS AND DISCUSSION: Some of our methods, results and conclusions yet unpublished are presented. For a preliminary calculation of area-related annual TNT dendroremediation potential of five-year-old trees, the following values were assessed: Salix EW-13 6.0, Salix EW-20 8.5, Populus ZP-007 4.2, Betula pendula 5.2, Picea abies 1.9 and Pinus sylvestris 0.8 g m(-2) a(-1). For a 45-year-old spruce forest, an annual natural attenuation potential of 4.2 g TNT m(-2) a(-1) was found. CONCLUSION, RECOMMENDATIONS AND PERSPECTIVE: Our main results deliver quantitative proposals for dendroremediation strategies in situ and provide decision aids. Also aspects of growth of raw materials for energy production are considered. Our dendroremediation research concept for TNT and its congeners can be easily completed for other trees of interest and it can also be applied to herbaceous plants. Knowing the current bottlenecks of phytoremediation and considering the known environmental behaviour of other contaminants, elements of our methodological approach may be easily adapted to those pollutant groups, e.g. for pesticides, pharmaceuticals, PAHs, chlorinated recalcitrants and, with some restrictions, to inorganics and to multiple contaminations. Our dynamical dendrotolerance test systems will help to predict tree growth on polluted areas. To provide some light into the black box of TNT dendroremediation, experimental data regarding the uptake, distribution and degradation of [14C]-TNT in mature tree tissues will be reported in the second part of this publication.     

Safety evaluation of leak in a storage tank using fault tree analysis and risk matrix analysis

The work presented in this paper used a quantitative analysis of relevant risks through the development of fault tree analysis and risk analysis methods to aid real time risk prediction and safety evaluation of leak in a storage tank. Criticality of risk elements and their attributes can be used with real time data to predict potential failures likely to occur. As an example, a risk matrix was used to rank risk of events that could lead to a leak in a storage tank and to make decisions on risks to be allowed based on past statistical data. An intelligent system that recognizes increasing level(s) and draws awareness to the possibility of additional increase before unsafe levels are attained was used to analyse and make critical decisions. After a visual depiction of relationships between hazards and controls had been actualized, dynamic risk modelling was used to quantify the effect controls can potentially have on hazards by applying historical and real-time data into a probabilistic model. The output of a dynamic risk model is near real-time quantitative predictions of risk likelihood. Results from the risk matrix analysis method mixed with RTD and FTA were analyzed, evaluated, and compared.