Leak location of pipelines based on characteristic entropy

The leakage of oil/gas pipelines is one of the major factors to influence the safe operation of pipelines. So it is significant to detect and locate the exact pipeline leakage. A novel leak location method based on characteristic entropy is proposed to extract the input feature vectors. In this approach, the combination of wavelet packet and information entropy is called “wavelet packet characteristic entropy” (WP-CE). The combination of empirical mode decomposition and information entropy is called “empirical mode decomposition characteristic entropy” (EMD-CE). Both pressure signal and flow signal of low noise and high noise of pipeline leakage are decomposed to extract the characteristic entropy. The location of pipeline leak is determined by the combination of the characteristic entropy as the input vector and particle swarm optimization and support vector machine method (PSO-SVM). The results of proposed leak location method are compared with those of PSO-SVM based on physical parameters. Under the condition of high noise, the results of proposed leak location method are better than those of PSO-SVM based on physical parameters.     

Decentralized scheme for leaks’ location in a branched pipeline

This article presents a novel scheme for the detection and isolation of single leaks in a pipeline with a branch junction by measuring only the flow rate and pressure at the ends of the line. For the solution of this realistic issue, which commonly occurs in pipeline networks, the position of the branch junction and its flow rate are supposed to be known. The idea consists of deriving a model considering the branch junction as a known point in the pipeline such that the leak position is characterized by two possible orientations with respect to the branch (upstream and downstream of it). Thus, this model allows proposing a diagnosis scheme which includes a static selector and two identifiers designed by using a continuous extended Kalman filter with only one deviation parameter to be estimated. This framework reduces the identification task to one parameter which is associated with the deviation from a prescribed positive base position located between one of the pipeline ends and the branch. Simulation and experimental results with data of a hydraulic pilot pipeline of 200 [m] show the promise of the novel scheme.     

厚壁管变形横波周向超声检测工艺及缺陷定位系统开发

在理论研究的基础上，利用试块对厚壁管变型横波与折射横波检测灵敏度进行了比较，证实了变型横波在厚壁管件中的检测灵敏度高于折射横波；设计开发计算软件，实现缺陷进行自动定位，大大提高现场检测效率和定位精度。     

基于Arcgis engine和Matlab的避难场所选址系统开发及应用

针对现有避难场所选址需要多种工具配合、操作步骤繁杂和工作量大的问题,开发了基于Arcgis engine和Matlab的避难场所选址系统。通过Arcgis engine实现避难场所选址所需的定制系统界面、空间数据管理、最短路径分析、缓冲区分析和voronoi图分析等GIS功能。通过Matlab构建多目标加权灰靶决策法和熵值权重法模型,实现避难场所选址功能。应用COM组件技术实现Arcgis Engine和matlab的集成。以泉州市中心城区为例,应用该系统进行应急避难场所选址决策分析。结果表明,该系统可以满足泉州市的应急避难场所选址及布局分析需求。     

采空区瓦斯涌出源位置对瓦斯浓度及自燃带分布的影响

利用Fluent软件,对采空区瓦斯为采空区整个区域涌出和上、下临近层及底板遗煤处同时涌出两种情况下的流场进行了数值模拟,并分析了采空区瓦斯体积分数及自燃带分布规律。结果表明:当采空区整个区域瓦斯涌出时,采空区瓦斯体积分数由底板到顶板垂直方向上呈逐渐升高的趋势;当上、下临近层及底板遗煤处瓦斯同时涌出时,采空区瓦斯体积分数在靠近底板和顶板位置处较高,中间区域处较低。与采空区整个区域瓦斯涌出相比,当上、下临近层及底板遗煤处瓦斯同时涌出时,在采空区底板处,自燃带更靠近工作面;在采空区底板和顶板中间位置处,自燃带远离工作面;在采空区顶板处,自燃带位置几乎没有变化。     

西南技术工程研究所, 重庆 400039

目的建立敦煌地区温度、相对湿度和日温差的年极值拟合模型。方法根据当地气象站台温度和相对湿度日记时值数据,连续统计若干年的三要素年极值,采用极大似然法建立各要素年极值的Gumbel模型,同时讨论值域有界类气象因素极值再现期的定义域。结果给出了敦煌地区温度、相对湿度和日温差年极值的Gumbel模型参数。结论敦煌地区各气象因素Gumbel模型位置参数和尺度参数,温度极大值分别为35.193,1.072℃,温度极小值分别为-20.085,1.945℃,相对湿度极大值为95.254%,2.471%,相对湿度极小值为5.837%,1.505%,日温差极大值为20.676,0.777℃,日温差极小值为1.398,0.593℃;相对湿度极大值、相对湿度极小值和日温差极小值的再现期定义域分别为6.3,47和10年。     

Predicted taxonomic patterns in pheromone production by longhorned beetles

Males of five species of three tribes in the longhorned beetle subfamily Cerambycinae produce volatile pheromones that share a structural motif (hydroxyl or carbonyl groups at carbons two and three in straight-chains of six, eight, or ten carbons). Pheromone gland pores are present on the prothoraces of males, but are absent in females, suggesting that male-specific gland pores could provide a convenient morphological indication that a species uses volatile pheromones. In this article, we assess the taxonomic distribution of gland pores within the Cerambycinae by examining males and females of 65 species in 24 tribes using scanning electron microscopy. Gland pores were present in males and absent in females of 49 species, but absent in both sexes of the remaining 16 species. Pores were confined to indentations in the cuticle. Among the species that had male-specific gland pores were four species already known to produce volatile compounds consistent with the structural motif. These findings support the initial assumption that gland pores are associated with the production of pheromones by males. There were apparently no taxonomic patterns in the presence of gland pores. These findings suggest that volatile pheromones play an important role in reproduction for many species of the Cerambycinae, and that the trait is evolutionarily labile.     

投入—转化—产出模型在工业污染源监测中的应用

本文把环境经济学中的有关原理和方法引入工业污染源监测工作中。详细介绍了产品物料投入—转化—产出全平衡模型的建立;并在此基础上进行工业污染源工艺剖析和有关计算,确定出工业污染源监测点位的布设和监测频率     

Environmental criteria in industrial facility siting decisions: An analysis

Environmental criteria are increasingly being employed in industrial facility siting, usually in multicriteria decision contexts, together with technical, socioeconomic and other considerations. This paper analyzes the criteria that have appeared in the published literature with the aim to offer guidance for their selection in a particular facility location problem. A number of alternative classification schemes are presented, first based on the most prevalent classification dimensions which are: the economy-environment relationship, purpose of the criterion, complexity, spatial and temporal scale, and level of measurement. The major scheme adopted draws from the economy-environment relationship and assigns environmental critera to one of seven categories: general characterizations of the environment, characteristics of individual environmental components, measures of the magnitude and intensity of the activity, measures of the nature and volume of wastes which are produced, characteristics of impacts on separate environmental media and receptors, general characterizations of environmental quality, and impacts on humans. Within each of these categories the criteria are analyzed in terms of the other classification dimensions. Common characteristics among the various criteria as well as future trends in their development are identified. This paper also discusses the most important factors conditioning the choice of criteria in a particular facility siting context and outlines a systematic procedure for their selection in real-world applications.     

Some thoughts on using a landscape framework to address cumulative impacts on wetland food chain support

Problems of using food chain support as a functional attribute of a wetland are discussed. It is suggested that primary production may not be the metric that best evaluates food chain support. Environmental constructs of the wetland and resultant habitat variables appear to yield more information on life-support functions. A landscape-oriented approach is derived to separate hierarchically the wet-lands into ecological regions and landscape elements. This classification scheme allows for predetermination of environmental constraints and the possible natural limits of wetland food chain support. It is proposed that models derived from spatial location theory be used to determine the movement of animals from wetland patches experiencing impacts on food chain support. Patch size, distance between patches, habitat diversity, and environmental constraints are incorporated in these models.