Reliability optimization using multiobjective ant colony system approaches

The multiobjective ant colony system (ACS) meta-heuristic has been developed to provide solutions for the reliability optimization problem of series-parallel systems. This type of problems involves selection of components with multiple choices and redundancy levels that produce maximum benefits, and is subject to the cost and weight constraints at the system level. These are very common and realistic problems encountered in conceptual design of many engineering systems. It is becoming increasingly important to develop efficient solutions to these problems because many mechanical and electrical systems are becoming more complex, even as development schedules get shorter and reliability requirements become very stringent. The multiobjective ACS algorithm offers distinct advantages to these problems compared with alternative optimization methods, and can be applied to a more diverse problem domain with respect to the type or size of the problems. Through the combination of probabilistic search, multiobjective formulation of local moves and the dynamic penalty method, the multiobjective ACSRAP, allows us to obtain an optimal design solution very frequently and more quickly than with some other heuristic approaches. The proposed algorithm was successfully applied to an engineering design problem of gearbox with multiple stages.     

Head Space—Solid Phase Micro Extraction Profile of Volatile Organic Compounds Emitted from Parquet Samples

The potential health risks posed by volatile organic compounds (VOCs) in homes are of concern. There is little information on indoor VOC emissions from wood flooring, called parquet. Six parquet samples were examined for VOCs in this preliminary study using Head Space—Solid Phase Micro Extraction (SPME) gas chromatography, a powerful and versatile analytical method which has been only minimally employed previously in wood chemistry. Prefinished composite samples released the highest levels of VOCs, mainly due to adhesives and finishes, with acetic acid the main component released from the oak component. As some VOCs from parquet present a health hazard, more comprehensive studies employing the SPME technique described herein are needed.     

Source Apportionment and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from Upper Reach of Huaihe River,China

Fifteen priority PAHs in 16 sediments from upper reach of Huaihe River collected in 2007 were measured. Source apportionment derived from PCA/MLR indicated that the highest contribution to ΣPAHs was from biomass burning (34.1%), followed by coal combustion (29.7%), vehicular emission (25.8%), and coke oven origin (10.4%). Risk assessment for each identified source was quantitatively calculated by combining the benzo[a]pyrene equivalent (BaPE) with estimated source contribution. The results showed that coal combustion posed the highest toxic risk, with BaPE value of 13.1 ng g^?1 dw, and the BaPE values for biomass burning, vehicular emission and coke oven were 5.6 ng g^?1 dw, 7.8 ng g^?1 dw, and 4.1 ng g^?1 dw, respectively. The distributions of contribution for total PAHs burden and BaPE of each identified source showed similar pattern among different sampling sites.     

Source apportionment of indoor residential fine particulate matter using land use regression and constrained factor analysis

Source contributions to urban fine particulate matter (PM(2.5) ) have been modelled using land use regression (LUR) and factor analysis (FA). However, people spend more time indoors, where these methods are less explored. We collected 3-4- day samples of nitrogen dioxide and PM(2.5) inside and outside of 43 homes in summer and winter, 2003-2005, in and around Boston, Massachusetts. Particle filters were analysed for black carbon and trace element concentrations using reflectometry, X-ray fluorescence (XRF), and high-resolution inductively coupled mass spectrometry (ICP-MS). We regressed indoor against outdoor concentrations modified by ventilation, isolating the indoor-attributable fraction, and then applied constrained FA to identify source factors in indoor concentrations and residuals. Finally, we developed LUR predictive models using GIS-based outdoor source indicators and questionnaire data on indoor sources. FA using concentrations and residuals reasonably separated outdoor (long-range transport/meteorology, fuel oil/diesel, road dust) from indoor sources (combustion, smoking, cleaning). Multivariate LUR regression models for factors from concentrations and indoor residuals showed limited predictive power, but corroborated some indoor and outdoor factor interpretations. Our approach to validating source interpretations using LUR methods provides direction for studies characterizing indoor and outdoor source contributions to indoor cocentrations. PRACTICAL IMPLICATIONS: By merging indoor-outdoor modeling, factor analysis, and LUR-style predictive regression modeling, we have added to previous source apportionment studies by attempting to corroborate factor interpretations. Our methods and results support the possibility that indoor exposures may be modeled for epidemiologic studies, provided adequate sample size and variability to identify indoor and outdoor source contributions. Using these techniques, epidemiologic studies can more clearly examine exposures to indoor sources and indoor penetration of source-specific components, reduce exposure misclassification, and improve the characterization of the relationship between particle constituents and health effects.     

浑河流域中上游河川径流变化特征分析

基于浑河流域中上游北口前站和大伙房水库站实测逐月径流资料,借助累积滤波器、Mann-Kendall法、分摊熵、绝对变化幅度和相对变化幅度等方法和指标,研究了浑河流域中上游河川径流年际和年内变化特征及趋势。结果表明,北口前站径流年内分配呈单峰型,其年径流呈不显著增加趋势,最大月径流由7月向8月转移;大伙房水库站径流年内呈双峰型分布,其年径流呈不显著减少趋势,汛期各月径流显著减少,非汛期各月径流增加;北口前站、大伙房水库站径流年内绝对变化幅度、相对变化幅度逐渐减小,但北口前站径流年内分配整体趋于更不均匀,大伙房水库站径流年内分配趋向于均匀,这有助于大伙房水库下游河流生态系统的健康和稳定。     

楼宇冷热电联供系统的热经济性分析

在对一实际楼宇冷热电联供系统热力学分析的基础上，对该系统作了热经济性分析，将作功能力法和热量法相结合，结合系统的实际经济数据。对该系统的成本进行分摊，得出了夏季变工况运行条件下冷、热、电三种产品的单位Yong成本和单位能成本，并对其进行了分析比较．结果表明：当系统保持足够的负荷率时，这种系统具有经济上的竞争力；而补燃措施会给系统的Yong效率和经济性带来很大的不利影响．     

南昌市罗家集工业区PM10源解析研究

采用理论设计、现场采样、实验室分析和模型计算相结合的方法,对南昌市罗家集工业区可吸入颗粒物(PM10)的来源进行定量解析.在南昌市南昌钢铁责任有限公司监测站和南昌市罗家集何家村监测点采集了 (PM10)的样品,同时收集了土壤尘、煤烟尘、冶金尘、建筑尘和机动车尾气尘等五种源样品.用等离子体发射光谱法(ICP)分别测定了受体和源样品中Ca、Mg、Al、As、Fe、Mn、Pb、S、Ti等9种的元素的含量,在此基础上建立了南昌市罗家集工业区源解析的化学质量平衡(CMB)受体模型,并利用CMB模型计算得到各种源对PM10污染的贡献率,分别为:煤烟尘32%、建筑尘22%、冶金尘16%、土壤尘13%、机动车尾气尘8%及其它尘9%.     

峰峰矿区降尘中正构烷烃分布规律及来源解析

按照季节变化,采集峰峰矿区三个采样点的降尘样品,并对其进行实验分析,得出峰峰矿区降尘中正构烷烃分布主要为后峰型及双峰型,均以C29为主峰碳,CPI值为1.54 - 10.54;通过分析认为该区春夏秋季降尘中正构烷烃主要来源于高等植物、花粉等生物有机质,冬季主要来源于煤等化石燃料燃烧,从春季到冬季生物质来源逐渐减少,化石燃料来源逐渐增多。     

朔州市区采暖期大气总悬浮颗粒物的源解析研究

应用受体模型的化学质量平衡法对采暖期朔州市市区5个监测点的总悬浮颗粒物（TSP）进行污染源的源解析.分析了朔州市TPS的主要来源,得出6类污染源对朔州市TSP的平均贡献率分别为：道路尘26.16%;原煤尘23.55%;民用煤烟尘18.96%;工业煤烟尘11.22%;土壤尘13.69%;建材尘6.47%.     

Source apportionment of river water pollution in a typical agricultural city of Anhui Province,eastern China using multivariate statistical techniques with APCS– MLR

The deterioration of the surface water environment has become a serious challenge for water resources management due to increasing anthropogenic disturbance. Water resources protection requires control of potential pollution sources. In this study, 99 water samples were collected from a river in a typical agricultural city of Anhui Province in eastern China, and these samples were analyzed in terms of pH, electrical conductivity, and the concentrations of F^-, Cl^-, SO₄^2-, Na⁺, K⁺, Mg²⁺, Ca²⁺, As, Cr, Cu, Zn, and Pb. Cluster analysis, co-occurrence network analysis, and principal component analysis/factor analysis were conducted to qualitatively identify the potential sources of river water pollution in the study area. An absolute principal component score-multiple linear regression receptor model was used to quantitatively evaluate the contribution of each source to water quality parameters. The results showed that all observed water quality indices met the quality criteria specified in the Chinese drinking water standards, except for pH, ρ(F^-), ρ(SO₄^2-), and ρ(As). The heat map showed that the frequent recharge of pollutants from the tributaries during the wet season was the main reason for the deterioration of water quality. Five sources of river water pollution were identified, and their contribution ratios in a descending order were as follows: the geogenic process (24%) > agricultural activities (21%) > poultry farming sources (17%) > domestic pollution (9%) > transportation pollution (5%). Therefore, controlling pollution from agricultural activities, strengthening the regulation of livestock farming, and improving the sewage network are the recommended strategies for improving the quality of surface water resources in this area.