Probabilistic Risk Assessment of Wastes Buried in the Ground

The differences between probabilistic risk assessment (PRA) and safety analysis (SA) are discussed, and it is shown that PRA is more suitable than SA for determining the acceptability of a technology. Since a PRA by the fault tree-event tree analysis method used for reactor safety studies does not seem to be practical for buried waste, an alternative approach is suggested using geochemical analogs. This method is illustrated for the cases of high-level and low-level radioactive waste and for chemical carcinogens released in coal burning.     

An Approach for Balancing Health and Ecological Risks at Hazardous Waste Sites

Human health and ecological risks must be balanced at hazardous waste sites in order to ensure that remedial actions prevent unacceptable risks of either type. Actions that are designed to protect humans may fail to protect nonhuman populations and ecosystems or may damage ecosystems. However, there is no common scale of health and ecological risk that would allow comparisons to be performed. This paper presents an approach to addressing this problem based on classifying all risks (i.e., health and ecological risks due contaminants and remediation) as insignificant ( de minimis ), highly significant ( de manifestis ), or intermediate. For health risks the classification is based on standard criteria. However, in the absence of national guidance concerning the acceptability of ecological risks, new ecological criteria are proposed based on an analysis of regulatory precedents. Matrices and flow charts are presented to guide the use of these risk categories in remedial decision making. The assessment of mercury contamination of the East Fork Poplar Creek is presented as an example of the implementation of the approach.     

Psychological Determinants of Reactions to Food Risk Messages

In recent years, European countries have witnessed a number of food crises such as dioxin-contaminated chicken, foot-and-mouth disease, and BSE. In such cases, food might be contaminated by microorganisms or chemicals that could pose a risk to the consumer. These cases attract media attention and might instigate the consumer to reduce the consumption of the allegedly contaminated products. Although a decline in consumption of (potentially) contaminated products has been observed, it is not yet clear what determines the individual's reaction to food risk messages. To study the psychological determinants of the reaction to food risk messages, a survey was conducted in the Netherlands (n= 280). Subjects had to imagine two situations involving chicken contamination and report how they would react behaviorally if this situation occurred. Risk perception, affective response, perceived susceptibility to foodborne disease, self-efficacy, outcome expectation, trust, experience with foodborne disease, and need for information were also assessed. It was found that 60% of the subjects would allegedly avoid the risks by not consuming chicken for a while and approximately 60% would seek additional information. Risk avoidance was significantly related to information seeking and the psychological determinants, especially risk perception, affective response, need for information, perceived susceptibility to foodborne disease, and trust. Seeking information was also significantly related to risk perception, affective response, need for information, susceptibility to foodborne disease, and trust, but to a lesser degree. A model describing the relationships between the variables was tested using AMOS. Results are presented and implications are discussed.     

精益化生产方式体现的管理新思想

精益化生产方式 (LeanProduction ,LP)是适应现代制造企业的一种生产组织管理模式。与传统的流水线生产组织形式相比 ,在生产组织运行体制、生产管理目标、LP系统的实施、员工激励等几个方面体现出许多新的思想值得我国企业学习和借鉴     

微型燃气轮机余热利用组合式吸附空调的试验研究

针对微型燃气轮机(MGT)余热利用的特点，采用吸附式冷管单元作为基本元件，进行了分子筛一水冷管组合型吸附式空调系统的设计和建造，并对系统的工作过程和原理进行了描述．利用模拟热源对空调器单床系统的总体性能状况进行了试验研究．     

Solid waste collection by the private sector: Households’ perspective—Findings from a study in Dar es Salaam city, Tanzania

The issue of poor solid waste management (SWM) is a challenge throughout the world, in both developed and developing countries. People always generate solid waste through their daily activities. This solid waste needs to be properly managed in a way that minimises risk to the environment and human health, which means storage, collection and proper disposal. At the same time solid waste creates livelihoods for the urban poor in terms of employment and business. This paper looks into one aspect of SWM, namely collection service.The importance of SWM is now recognised at international, national and community level. The Agenda 21 declaration of the United Nations [UN. (1993). The global partnership for environment and development: A guide to agenda 21 (pp. 88–94). New York: United Nations] addresses the issue of environmentally sound management of solid waste, with emphasis on the extension of solid waste service coverage to all urban and rural areas worldwide.SWM is a service for which local governments are usually responsible. However, due to inadequate capacity in the public sector, in many developing countries the private sector has stepped in to fill the gap in service provision. Dar es Salaam (DSM), Tanzania, is one such developing country city in which the private sector has become involved in solid waste collection services. The sector comprises Non-Government Organisations (NGOs), Community-Based Organisations (CBOs), and local private companies [Kassim, S. M., & Ali, S. M. (2003). Private solid waste collection SERVICE, Dar es Salaam Tanzania. In Proceedings of the 29th WEDC international conference: Towards millenium development goals. Abuja Nigeria, Water and Engineering Centre WEDC]. The private sector in solid waste collection in DSM has been promoted by Sustainable DSM Programme (SDP) through Environmental Planning and Management (EPM) [UNCHS. (1994a). Sustainable Human Settlements Development: Implementing Agenda 21; UNCHS. (1994b). UNCHS (Habitat) Activities; New Envoy to UNCHS from the United Republic of Tanzania. Habitat News, 16, 1–3].Contracting out of solid waste collection services to the private sector has emerged to fill the gap in service delivery. In 1991 the city was generating 1400 tonnes of solid waste per day out of which only 5% was being collected. Currently daily solid waste generation is estimated at about 2500 tonnes and approximately 48% of the total waste generated is collected. At present, privatisation covers 44 out of 73 city wards, and 45¹ active registered private companies are involved [Chinamo, E. B. M. (2003). An overview of solid waste management and how solid waste collection benefits the poor in the city of Dar es Salaam. Solid waste collection that benefits the poor, Dar es Salaam, Tanzania, Collaborating Working Group on Solid Waste Management in Low and Middle -Income Countries (CWG)].This paper presents the findings of a study that explored the households’ perspective on solid waste collection services provided by the private sector. The study showed that the solid waste collection service by the private sector is greatly influenced by households’ attitudes and behaviour. Their participation, demand for service, awareness, satisfaction level and views on cost recovery are important in the sector. The study concludes that the above factors would be superior if customers (households) were more involved in the planning and decision-making.     

Infant Exposure Assessment for Breast Milk Dioxins and Furans Derived from Waste Incineration Emissions

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have been detected in human milk samples obtained in several countries. Possible sources include emissions from incineration of municipal waste in resource recovery facilities. A formula is presented for calculating the infant daily dose of dioxin equivalents from breast milk on the basis of the maternal daily intake. Application of the formula suggests that an infant breast-fed for 12 months would receive around 10% of the cumulative exposure dose per body weight that would be received by an adult with 50 years of exposure. Further analysis indicated that the contribution of dioxin equivalents from breast milk to an infant's body concentration at the end of 12 months of breast feeding would amount to 1.7 times the concentration in the mother. However, dioxin and furan emissions from a source calculated to result in worst-case lifetime cancer risks of the order of 1 in 100,000 are only likely to increase breast milk concentrations by around 1%-10% of the levels that have been detected in several countries. This finding suggests that there are major sources of dioxins and furans other than from municipal solid waste incineration that need to be identified.     

Consumer Phase Risk Assessment for Listeria monocytogenes in Deli Meats

The foodborne disease risk associated with the pathogen Listeria monocytogenes has been the subject of recent efforts in quantitative microbial risk assessment. Building upon one of these efforts undertaken jointly by the U.S. Food and Drug Administration and the U.S. Department of Agriculture (USDA), the purpose of this work was to expand on the consumer phase of the risk assessment to focus on handling practices in the home. One-dimensional Monte Carlo simulation was used to model variability in growth and cross-contamination of L. monocytogenes during food storage and preparation of deli meats. Simulations approximated that 0.3% of the servings were contaminated with >10(4) CFU/g of L. monocytogenes at the time of consumption. The estimated mean risk associated with the consumption of deli meats for the intermediate-age population was approximately 7 deaths per 10(11) servings. Food handling in homes increased the estimated mean mortality by 10(6)-fold. Of all the home food-handling practices modeled, inadequate storage, particularly refrigeration temperatures, provided the greatest contribution to increased risk. The impact of cross-contamination in the home was considerably less. Adherence to USDA Food Safety and Inspection Service recommendations for consumer handling of ready-to-eat foods substantially reduces the risk of listeriosis.     

废弃电子产品回收再利用网络组织演化研究

废弃电子产品回收再利用成为发展循环经济的主要途径之一.在对废弃电子产品回收再利用网络组织演化阶段系统分析的基础上,建立废弃电子产品回收再利用网络组织演化模型,并运用Swarm仿真平台对模型进行仿真,得出演化规律.研究表明：基于SDN的废弃电子产品回收再利用网络组织较联盟回收再利用网络组织在回收再利用总成本和效率上更有优势.