Leak location of pipelines based on transient model and PSO-SVM

An improved and integrated approach of support vector machine and particle swarm optimization theory (PSO-SVM) is first used to detect the leak location of pipelines and overcome the problem of multiple leaks. The calibration and predictive ability of improved PSO-SVM is investigated and compared with that of other common method, back-propagation neural network (BPNN). Two conditions are evaluated. One with a leak involves a set of 20 samples, while another with two leaks has 127 samples. Both internal and external validations are performed to validate the performance of the resulting models. The results show that, for the two conditions, the values calculated by improved PSO-SVM are in good agreement with those simulated by transient model, and the performances of improved PSO-SVM models are superior to those of BPNN. This paper provides a new and effective method to inspect the multiple leak locations, and also reveals that improved PSO-SVM can be used as a powerful tool for studying the leak of pipeline.     

基于面源模型的城市内部居住环境区位优势度分析

首先,利用ARC/INFO平台将研究区域划分成若干元胞(cell),作为居住环境区位优势度空间评价基本单元,各种统计运算以元胞为单位进行,结果通过元胞显示出来,就可以构造面源模型。运用该模型对居住环境区位优势度研究,有效解决了不同空间单元信息如何在同一单元融合的问题,弥补以往选取若干典型小区的片状研究方法的若干不足。其次,对佳木斯市居住环境区位优势度进行分析,最后,在Arcmap平台下,充分发挥GIS的逻辑查询和图形叠置功能,建立了呈不规则四圈层的单核心居住环境区位优势度评价空间结构模式图。     

Agricultural Pesticide Residues in Farm Ditches of the Lower Fraser Valley,British Columbia,Canada

Transient and permanent farm ditches flowing to the Lower Fraser River tributary fish streams of British Columbia, Canada, were sampled at several locations in 2003–2004 to determine the occurrence and concentration of residues of selected pesticides, their transformation products, and soluble/extractable Cu⁺⁺ ions. Of the 43 compounds analyzed, 28 and 22 pesticides were detected in transient farm ditch water and sediments, respectively. About 34% fewer pesticides, however, were found in both matrices of permanent farm ditches. Average concentrations (μ g L^?1) of those most frequently detected in permanent farm ditch water were atrazine (0.20), α -chlordane (0.06), desethylatrazine (0.13), diazinon (0.55), dieldrin (0.28), endosulfan sulfate (0.16), glyphosate (6), metalaxyl (0.27); and soluble Cu⁺⁺ ions (25). Those most often found in ditch sediments (μ g kg^?1) were aminomethylphosphonic acid (AMPA) (2,300), 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) (250), endosulfan sulfate (500), glyphosate (1,225); and extractable Cu⁺⁺ ions (58,000). The risk potential of these pesticide residues to non-target aquatic organisms inhabiting Fraser River tributary fish streams contiguous to permanent farm ditches is evaluated and discussed.     

A hybrid model for remanufacturing facility location problem in a closed-loop supply chain

Traditional supply chain design is merely based on the open loop or forward flow of materials, neglecting reverse flow for recovery of materials despite the recent concerns of customers and governments about environmental and production cost reductions. New supply chain design should be closed loop which implements traditional supply chain concepts with reverse flow or a material recovery system to reduce production cost and enhance customer satisfaction about environmental consciousness and to meet legal requirements. In our research, we designed a closed-loop supply chain which consists of recovery options such as collection centres and remanufacturing plants (reverse flow) in addition to traditional supply chain tiers (forward flow), and tried to find the best location for these facilities in a discrete space based on decision makers' opinions. Since there are uncertainties about decision parameters in an uncapacitated facility location problem, we implemented the fuzzy TOPSIS method to solve the location decision problem and find the best place to locate a remanufacturing facility.     

Perception of drinking water in the Quebec City region (Canada): the influence of water quality and consumer location in the distribution system

The purpose of every water utility is to provide consumers with drinking water that is aesthetically acceptable and presents no risk to public health. Several studies have been carried out to analyze people's perception and attitude about the drinking water coming from their water distribution systems. The goal of the present study is to investigate the influence of water quality and the geographic location of consumers within a distribution system on consumer perception of tap water. The study is based on the data obtained from two surveys carried out in municipalities of the Quebec City area (Canada). Three perception variables were used to study consumer perception: general satisfaction, taste satisfaction and risk perception. Data analysis based on logistic regression indicates that water quality variations and geographic location in the distribution system have a significant impact on the consumer perception. This impact appears to be strongly associated with residual chlorine levels. The study also confirms the importance of socio-economic characteristics of consumers on their perception of drinking water quality.     

红吉水库诱发地震分析研究

在国内外水库诱震研究成果的基础上,结合红吉水库地震、天然应力场状态、地震活动性和水库运行条件等实际资料,采用概率统计法和模糊评判法,初步判定红吉水库具有小概率的诱发地震危险性,库区附近的北北东向和北北西向断裂是可能的发震位置,最大可能诱发的地震震级为4级.     

Export inherent safety NOT risk

The author presents a personal view that production of bulk chemicals and the attendant risks are being transferred from developed to developing nations. Some evidence is presented on the transfer of production. The transferred risk is increased because of the larger scale plants that are now built in locales that are less able to cope with the increased hazards. Bhopal was an example of an inherently unsafe plant, with major hazards that could have been avoided or drastically reduced by design. It behoves the industry to adopt the inherently safer philosophy and practice in the new plants that it builds, in order to minimise the opportunity for another accident like Bhopal and the threat to our industry that such an accident would pose.     

Exploring diversity in soil fertility management of smallholder farms in western Kenya: I. Heterogeneity at region and farm scale

The processes of nutrient depletion and soil degradation that limit productivity of smallholder African farms are spatially heterogeneous. Causes of variability in soil fertility management at different scales of analysis are both biophysical and socio-economic. Such heterogeneity is categorised in this study, which quantifies its impact on nutrient flows and soil fertility status at region and farm scales, as a first step in identifying spatial and temporal niches for targeting of soil fertility management strategies and technologies. Transects for soil profile observation, participatory rural appraisal techniques and classical soil sampling and chemical analysis were sampled across 60 farms in three sub-locations (Emuhaia, Shinyalu, Aludeka), which together represent much of the variability found in the highlands of western Kenya. Five representative farm types were identified using socio-economic information and considering production activities, household objectives and the main constraints faced by farmers. Soil fertility management and nutrient resource flows were studied for each farm type and related to differences in soil fertility status at farm scale. Farm types 1 and 2 were the wealthiest; the former relied on off-farm income and farmed small pieces of land (0.6–1.1 ha) while the latter farmed relatively large land areas (1.6–3.8 ha) mainly with cash crops. The poorest farm type 5 also farmed small pieces of land (0.4–1.0 ha) but relied on low wages derived from working for wealthier farmers. Both farm types 1 and 5 relied on off-farm earnings and sold the least amounts of farm produce to the market, though the magnitude of their cash, labour and nutrient flows was contrasting. Farms of types 3 and 4 were intermediate in size and wealth, and represented different crop production strategies for self-consumption and the market. Average grain yields fluctuated around 1 t ha⁻¹ year⁻¹ for all farm types and sub-locations. Grain production by farms of types 4 and 5 was much below annual family requirements, estimated at 170 kg person⁻¹ year⁻¹. Household wealth and production orientation affected the pattern of resource flow at farm scale. In the land-constrained farms of type 1, mineral fertilisers were often used more intensively (ca. 50 kg ha⁻¹), though with varying application rates (14–92 kg ha⁻¹). The use of animal manure in such small farms (e.g. 2.2 t year⁻¹) represented intensities of use of up to 8 t ha⁻¹, and a net accumulation of C and macronutrients brought into the farm by livestock. In farms of type 5, intensities of use of mineral and organic fertilisers ranged between 0–12 kg ha⁻¹ and 0–0.5 t ha⁻¹, respectively. A consistent trend of decreasing input use from farm types 1–5 was generally observed, but nutrient resources and land management practices (e.g. fallow) differed enormously between sub-locations. Inputs of nutrients were almost nil in Aludeka farms. Both inherent soil properties and management explained the variability found in soil fertility status. Texture explained the variation observed in soil C and related total N between sub-locations, whereas P availability varied mainly between farm types as affected by input use.     

Community and farm forestry climate mitigation projects: case studies from Uttaranchal,India

The methodologies for forest mitigation projects still present challenges to project developers for fulfillment of criteria within the Clean Development Mechanism (CDM) or other such mechanisms for the purpose of earning carbon credits. This paper systematically approaches the process of establishing carbon (C) stocks for baseline (BSL) and mitigation scenario (MSL) for two case studies i.e., community and farm forestry projects in Uttaranchal, India. The analysis of various interventions shows that both projects present high carbon mitigation potential. However, the C reversibility risk is lower in long-rotation pine and mixed species plantation on community lands. The project is financially viable though not highly lucrative but the carbon mitigation potential in this ‘restoration of degraded lands’ type of project is immense provided challenges in the initial phase are adequately overcome. C revenue is an essential driver for investors in community projects. The short-rotation timber species such as Eucalyptus (Eucalyptus), Poplar (Populus) have high internal rates of return (IRR) and high carbon benefit reversibility potential due to fluctuations in market prices of commodities produced. The land holdings are small and bundling is desired for projects to achieve economies of scale. The methodological concerns such as sampling intensities, monitoring methodologies, sharing of benefits with communities and bundling arrangements for projects need further research to make these projects viable.