Hazard assessment of chemical air contaminants measured in residences

Identifying air pollutants that pose a potential hazard indoors can facilitate exposure mitigation. In this study, we compiled summary results from 77 published studies reporting measurements of chemical pollutants in residences in the United States and in countries with similar lifestyles. These data were used to calculate representative mid-range and upper-bound concentrations relevant to chronic exposures for 267 pollutants and representative peak concentrations relevant to acute exposures for five activity-associated pollutants. Representative concentrations are compared to available chronic and acute health standards for 97 pollutants. Fifteen pollutants appear to exceed chronic health standards in a large fraction of homes. Nine other pollutants are identified as potential chronic health hazards in a substantial minority of homes, and an additional nine are identified as potential hazards in a very small percentage of homes. Nine pollutants are identified as priority hazards based on the robustness of measured concentration data and the fraction of residences that appear to be impacted: acetaldehyde; acrolein; benzene; 1,3-butadiene; 1,4-dichlorobenzene; formaldehyde; naphthalene; nitrogen dioxide; and PM(2.5). Activity-based emissions are shown to pose potential acute health hazards for PM(2.5), formaldehyde, CO, chloroform, and NO(2). PRACTICAL IMPLICATIONS: This analysis identifies key chemical contaminants of concern in residential indoor air using a comprehensive and consistent hazard-evaluation protocol. The identification of a succinct group of chemical hazards in indoor air will allow for successful risk ranking and mitigation prioritization for the indoor residential environment. This work also indicates some common household activities that may lead to the acute levels of pollutant exposure and identifies hazardous chemicals for priority removal from consumer products and home furnishings.     

硫化矿炸药自爆新判据和治理措施研究

在现场试验研究的基础上,分析了硫化矿山炸药自爆机理,以Fe2+为指标代替了以往的炸药自爆判据,建立了矿样水溶液中Fe2+与其pH值关系的回归经验公式,提出了以pH值为指标的炸药自爆新判据和简便实用准确的检测方法以及按炸药自爆危险程度对采区进行有效分区的治理措施,较好地防止了矿山炸药自爆且节约了爆破成本。实践证明,本研究成果是实用和安全的,具有明显的经济效益和社会效益,为进一步深入研究炸药自爆理论与预防措施提供借鉴。     

基于非均匀采样的小卫星多通道SAR无模糊成像

当小卫星天线不满足最小天线面积约束时,则出现距离或者方位模糊,无模糊的高分辨成像是小卫星SAR成像处理的关键.本文提出利用分布式小卫星或者小卫星天线的多通道回波数据,在满足广义采样定理的条件下通过插值恢复出无模糊的全方位带宽信号,实现高分辨成像.实验证明,该算法具有操作简单,运算效率高的优点.     

Multi Criteria Analysis for bioenergy systems assessments

Sustainable bioenergy systems are, by definition, embedded in social, economic, and environmental contexts and depend on support of many stakeholders with different perspectives. The resulting complexity constitutes a major barrier to the implementation of bioenergy projects. The goal of this paper is to evaluate the potential of Multi Criteria Analysis (MCA) to facilitate the design and implementation of sustainable bioenergy projects. Four MCA tools (Super Decisions, DecideIT, Decision Lab, NAIADE) are reviewed for their suitability to assess sustainability of bioenergy systems with a special focus on multi-stakeholder inclusion. The MCA tools are applied using data from a multi-stakeholder bioenergy case study in Uganda. Although contributing to only a part of a comprehensive decision process, MCA can assist in overcoming implementation barriers by (i) structuring the problem, (ii) assisting in the identification of the least robust and/or most uncertain components in bioenergy systems and (iii) integrating stakeholders into the decision process. Applying the four MCA tools to a Ugandan case study resulted in a large variability in outcomes. However, social criteria were consistently identified by all tools as being decisive in making a bioelectricity project viable.     

Normal Range Criteria for Indoor Air Bacteria and Fungal Spores in a Subarctic Climate

Indoor air bacteria and fingal spore levels were studied in 71 non-complaint homes. lk data were analyzed according to the season and the higher limit of the range within which 95% of the cases fall was computed. On the basis of the data the following highest normal levels are proposed for winter: for bacteria 5000 cfulm³ and for fingal spores 500 cfulm³. The recommended levels apply in a subarctic climate for urban and suburban homes when the measurements are made using the same method as in this study. We recommend that if abnormal indoor sources are suspected, indoor samples should be taken in winter when the ground is frozen and covered with snow. At that time, the background levels are at their lowest and the abnormal indoor sources are most easily detected. lk recommended levels should not be used as an indicator of a health risk, but as an indication of abnormal indoor sources or insufficient ventilation.     

Fuzzy multiple attributes and multiple hierarchical decision making

A procedure is proposed to solve the multiple attributes and multiple hierarchical system under fuzzy environment. The approach is based on:

1. (1) fuzzy representation;

2. (2) hierarchical performance evaluation structure,

3. (3) gradient eigenvector method for rating the fuzzy criteria weighting, and

4. (4) using the max-min paired elimination method for aggregation.

To illustrate the approach, an example on the evaluation of teaching performance in higher education is solved.     

水堆压力容器的脆性断裂——准则、标准及其应用

根据防止反应堆压力容器脆性断裂的准则,较为详细地叙述了防止脆性断裂的有关规定,讨论了材料韧性指标及其相互关系、辐照效应及断裂分析内容,最后提出了作者看法.     

Development of a criterion for azeotrope prediction of binary refrigerant mixtures

A simple criterion for binary azeotrope formation of refrigerant mixtures based on the regular solution theory was developed and applied to several refrigerant mixtures. This criterion requires no complex calculation and can be easily applied when vapor pressure and saturated density data of pure components are available. It was proven that the formation of an azeotrope could be well predicted with this criterion for the mixtures we studied. This paper is dedicated to Professor Wha Yong Lee on the occasion of his retirement from Seoul National University.     

EFFECT OF GAS-SIDE RESISTANCE ON STEADY STATE MULTIPLICITY IN GAS-LIQUID CSTRs

The effect of gas-side resistance to mass transfer on the existence and uniqueness of steady states in gas-liquid CSTRs is analyzed. It is shown that there exists an upper bound on gas-side resistance beyond which multiplicity cannot arise.     

基于国Ⅳ标准的便携式汽车尾气分析仪的设计

基于GB 18352.3-2005(国IV标准)设计了一种便携式智能汽车尾气分析仪。该分析仪以ARM微控制器为核心,具有实时检测与动态显示、支持燃烧分析与故障诊断、操作简单及携带方便等一系列特点。实现了国IV标准的各种型式核准,模糊分类方法支持对发动机的燃烧情况分析和故障诊断。试验结果表明:系统具有优良的分析性能。