北京市道路绿地消减PM2.5总量及其健康效益评估

以交通污染严重的北京市建成区为研究区,在前人实地观测的基础上,利用泊松回归相对风险度模型与环境健康价值评估方法,定量评估了北京市道路绿地消减PM2.5总量及其健康效益.结果表明:北京市建成区道路绿地年消减PM2.5总量为1.09t;对降低人群健康风险作用较为显著,可减少受危害总数约3024例,其中早逝18例、呼吸系统疾病住院53例、心血管疾病住院25例、儿科门诊324例、内科门诊761例、急性支气管炎1134例、慢性支气管炎264例、哮喘445例;带来的健康经济效益为1.98亿元.建议加强道路绿地建设,丰富植被层次结构,以积极应对城市交通空气污染.     

基于PLM的矿用低压变频器漏电机理的研究

解释了矿井低压电网系统引入变频器后单相漏电故障电流增大的机理。以人身触电事故为研究对象,建立煤矿井下低压电网变频器系统单相漏电故障的分段线性模型,推导出故障电流的有效值,并经 MATLAB 仿真进行了验证。其分析结果表明,人身触电电流大幅度提高,人身安全水平显著下降。并进一步归纳出矿井低压电网变频器系统单相漏电故障电流的影响因素及一般规律。实验结果验证了理论分析与仿真的正确性。     

Septic tank and agricultural non‐point source pollution within a rural watershed

This investigation addresses the problem of Non‐Point Source (NPS) pollution in the rural Lake Weatherford watershed in Parker County, Texas. This reservoir is the primary municipal water supply for the City of Weatherford, Texas. The principal method of wastewater disposal is the on‐site system or septic tanks for the small residential areas surrounding the reservoir.

Sources of NPS pollution of interest in this watershed include agricultural operations as well as the residential areas. These sites were identified with the aid of aerial photography and field investigation. Suspected NPS problems were substantiated through a sampling program involving chemical and biological testing of the reservoir. Results indicate that there is significant NPS pollution contamination of Lake Weatherford from agricultural sources and seepage from on‐site wastewater disposal systems. Excessive fecal coliform and fecal streptococcus counts (>500 bacteria/100 ml) were generally associated with rainfall events and several samples showed values > 100000 bacteria/100 ml. The fecal coliform/fecal streptococcus ratios indicated contamination from human sources, animal sources, and a combination of both. Nutrient concentrations fluctuated from quite low to high with ammonia as the most consistent problem. High ammonia values were also associated with rainfall events.     

Green supply chain management in the chemical industry: structural framework of drivers

ABSTRACT

The main purpose of Green Supply Chain Management (GSCM) is to improve the quality of supply chain management strategies and environmental performance. As per current statistics, the chemical industry is growing fast in Bangladesh. In order to compete for global competition, GSCM is essential in this sector. This paper proposes a systematic approach of structural framework whose aim is to enhance the probability of constructive implementation of GSCM in the field chemical industry in Bangladesh. Therefore, this framework evaluates the appropriate interrelationship along with the drivers of GSCM in the chemical industry. In total, eight drivers were finalized from an associated literature review with the help of survey and by taking expert opinions via the Delphi methodology. In addition to MICMAC analysis, the driving and the dependence powers for all the drivers were determined. Moreover, the structural frameworks for the drivers were developed by means of total interpretive structural modeling (TISM) technique. As a result, the findings indicate that the most significant driver was supplier pressure and willingness and the most important barrier was high cost. Finally, the main objective of this research is expected to help industrial managers to evaluate and understand the critical areas where they should emphasize to implement GSCM in the chemical industry.     

基于Gompertz曲线的石油库罐区火灾灭火剂供应量预测

石油库罐区火灾的成功扑救依赖于灭火剂量的充足供应。结合火灾发展阶段特点,发现火灾中灭火剂供应量发展规律基本符合Gompertz曲线。于是,在对火场扑救力量作战能力分析的基础上,以灭火剂使用量为标准,对作战能力进行量化分析,将量化数值和时间段编号作为基础数据,建立Gompertz趋势预测模型。利用预测模型对石油库罐区类火灾灭火剂供应量进行预测,排除了人为估算的盲目性,避免灭火剂调用“供过于求”的现象。     

Multi-objective synthesis of a company's supply network by accounting for several environmental footprints

This contribution presents the multi-objective synthesis of a company's supply network by integrating renewables (biomass and other waste, and solar energy) and accounting for several environmental footprints. The synthesis is based on a Mixed-Integer Linear Programming (MILP) problem. A previously developed model by the authors for achieving energy self-sufficiency by integrating renewables into companies’ supply networks has been extended for the evaluation of environmental impacts, such as energy, carbon, nitrogen, and water footprints. The achievement of an energy self-sufficient supply network has been considered whilst significantly reducing environmental impacts.The presented model is applied to multinational poultry-meat producing company. Direct (burdening) and indirect (unburdening) effects that form total effects on the environment are considered for the evaluation of environmental footprints. The results showed significant unburdening of the environment in terms of carbon and nitrogen footprints but, however, higher burdening in terms of the water footprint.     

Seismic vulnerability assessment of water supply network in Tianjin,China

The water supply network （WSN） system is a critical element of civil infrastructure systems. Its complexity of operation and high number of components mean that all parts of the system cannot be simply assessed. Earthquakes are the most serious natural hazard to a WSN, and seismic risk assessment is essential to identify its vulnerability to different stages of damage and ensure the system safety. In this paper, using a WSN located in the airport area of Tianjin in northern China as a case study, a quantitative vulnerability assessment method was used to assess the damage that the water supply pipelines would suffer in an earthquake, and the finite element software ABAQUS and fuzzy mathematic theory were adopted to construct the assessment method. ABAQUS was applied to simulate the seismic damage to pipe segments and components of the WSN. Membership functions based on fuzzy theory were established to calculate the membership of the components in the system. However, to consider the vulnerability of the whole system, fuzzy cluster analysis was used to distinguish the importance of pipe segments and components. Finally, the vulnerability was quantified by these functions. The proposed methodology aims to assess the performance of WSNs based on pipe vulnerabilities that are simulated and calculated by the model and the mathematical method based on data of damage. In this study, a whole seismic vulnerability assessment method for a WSN was built, and these analyses are expected to provide necessary information for a mitigation plan in an earthquake disaster.     

自动扶梯曳引机由静态元件供电的拖动线路及PLC控制

文章分析了GBI6899—2011《自动扶梯和自动人行道的制造与安装安全规范》中曳引电机由静态元件供电的要求,讨论了使用两个和一个电源接触器切断曳引机供电的线路。并优先使用一种两个电源接触器切断供电的线路,设计了该线路的一种PLC控制电路,讨论了其起动和停止的控制过程。并给出了PLC控制梯形图程序的结构图。     

不同植被类型下土壤胡敏酸降解特性

为了解不同植被类型下土壤HA(胡敏酸)降解菌的种类、分布状况及其中C的降解程度,选取退耕还林典型地带,于农田、油松、刺槐、沙棘、混交林0~10cm土样中分别提取HA,利用HA作为唯一C、N源筛选HA降解微生物. 结果表明:相比农田土壤HA,各林地土壤HA中w(C)增加,w(N)有所减少;共分离获得5株HA降解菌,根据16s rRNA序列鉴定,分别为Bacillus licheniformis、Rhizobium nepotum、Microbacterium resistens、Stenotrophomonas maltophilia、Streptomyces azureus,相似度分别为99.65%、99.78%、98.71%、99.23%、99.78%. 农田、刺槐、油松及混交林的降解菌优势种为Bacillus licheniformis,沙棘优势种为Streptomyces azureus,刺槐无Rhizobium nepotum分布,沙棘和混交林无Stenotrophomonas maltophilia分布;降解菌数量为沙棘>刺槐>农田>油松>混交林,混交林仅为沙棘的58.87%;混交林、油松、沙棘、刺槐降解菌的RC(呼吸量碳)分别较农田高出25.35%、11.28%、10.36%、7.11%,混交林与农田差异显著(P<0.05). 沙棘、刺槐、农田、油松降解菌MBC(微生物生物量碳)分别较混交林高出131.91%、68.48%、64.98%、54.47%,刺槐、农田、油松三者与沙棘及混交林差异显著(P<0.05). 沙棘土壤HA的TDR(总降解率)明显高于农田和混交林(P<0.05). 相关性分析表明,降解菌数量与MBC呈极显著正相关,与RC呈极显著负相关(P<0.01). 结果表明,植被类型影响了土壤HA降解菌的群落组成及其降解特性.      

PROTECTING BEIJLNG'S MUNICIPAL WATER SUPPLY THROUGH WATERSHED MANAGEMEN AN ECONOMIC ASSESSMENT1

ABSTRACT: Watersheds above the Miyun reservoir, a principal source of surface water for Beijing, are designated to be managed for water production, but under the principle of multiple use. Because of the scarcity of arable land, these watersheds cannot be managed only for drinking water. Efforts are under way to reduce sediment delivery, improve the quality of water entering Miyun reservoir, and improve the welfare of watershed inhabitants. An economic appraisal of a watershed management project for the 3,298‐ha Shixia watershed above the Miyun reservoir, indicates a 24 percent economic rate of return on the investment made in the project. The net present value (NPV) of the project, calculated at a discount rate of 10 percent, is approximately US$3.49 million. Sensitivity analyses indicate that a doubling of labor costs lowers the NPV to US$2.07 million and a 10 percent decrease in benefits lowered the NPV to US$2.87. It is concluded that the implementation of conservation practices on the Shixia Demonstration Watershed represent an economically efficient use of resources.