基于DFT与量子拓扑学的氯代二苯并呋喃QSPR研究

为了研究多氯代二苯并呋喃（PCDFs）在云杉针叶和飞灰表面的光解半衰期（t1／2）与其结构的定量关系,本文应用密度泛函理论（DFT）,在B3LYP／6—31＋G（d）基组上优化和振动分析计算了48种PCDFs的分子空间几何结构,得到其各原子之间空间拓扑距离,并建立拓扑空间距离矩阵．结合分子中各原子的支化度,应用原子平衡电负性对分子图进行着色修饰,得到量子拓扑指数XP1、XP2．采用偏最小二乘回归法（PLS）对48种PCDFs在云杉针叶和飞灰表面的t1/2进行模拟分析,分别得到2定量结构一性质相关（QSPR）模型,并用这种模型对t1/2进行预测,结果表明预测结果和实验值吻合较好．同时对QSPR拓扑模型采用留一检验法（LOO）进行测试,测试结果显示模型具有良好稳定性和较强的预测能力．     

新疆农六师所在地水资源承载能力研究

分析新疆农六师所在地现状水资源开发利用情况及存在的问题,构建了水资源优化配置模型,通过不同方案长系列逐月调节计算和对比分析,选取中方案为水资源配置推荐方案。同时,采用双指针计算模型计算农六师高、中、低三种需水方案的水资源承载能力,指出现状年105团当地水资源已经处于超载状态,到2030年农六师的经济中心五家渠市也将处于水资源超载边缘,超载度为0.97。最后,探讨了如何提高农六师所在地水资源承载能力的途径,为农六师实现跨越式可持续发展提出建议。     

旱情评估指标研究简介及探讨

干旱灾害是我国发生最为频繁、影响范围较大,并造成严重危害的一种气象灾害。由于干旱自身的复杂性及对社会影响的广泛性,干旱指标的确定和分析对干旱的监测及评估有重要的意义,同时也为全球变化中的气候一植被关系研究提供方法和依据。将干旱指标从气象、水文、农业和社会经济4方面进行综述,介绍了国内外干旱指标研究现状及最新动态,并指出其优势和不足,以此提出今后干旱指标研究重点与展望。     

SELECTING HYDROLOGIC INDICES FOR THE PRAIRIE PROVINCES

The large and accumulating body of evidence for both the controlling effect of the flow regime on river ecology and for the dependence of river health on the natural flow regime has led to the increasing use of hydrologic indices in instream flow studies. The myriad of collinear hydrologic indices present a daunting challenge to water managers trying to select a manageable number of indices for use in a hydrology‐based environmental flow framework. In this study, a large number of hydrologic indices were calculated from gauging sites in the prairie provinces of Canada. Principal component analysis (PCA) and two rank‐based non‐parametric techniques are compared in their ability to select a small number of statistically informative indices. Despite the data being skewed and far from normal, PCA and the non‐parametric technique called BioEnv + stepwise (BEST) both led to similar interpretations and could identify a small number of indices that capture a majority of the statistical variability. BEST selected indices more evenly from among conceptual categories of flow than PCA. Copyright © 2011 John Wiley & Sons, Ltd.     

Analysing the extent (size and shape) of Lake Basaka expansion (Main Ethiopian Rift Valley) using remote sensing and GIS

This study attempted to estimate the extent of the expansion of the area of Lake Basaka over the past 50 years (1960 to 2010), using LANDSAT images, field observations, local information and topographic maps. The analysis revealed that the lake has exhibited a dramatic expansion over the past five decades. An increase in the lake water level by 7.6 m over this period resulted in flooding about 45.8 km² of surrounding areas and an incremental lake volume of about 280 Mm³. About 70% of the lake expansion was observed in the period between the 1970s and 1990s. This phenomenon coincides with the periods of remarkable land use/cover changes in the region. Furthermore, the beginning of the lake expansion coincided with the introduction of irrigated agriculture in the region, and construction of Koka Dam in the mid‐1960s in the upper Awash River Basin. This study suggests that the observed expansion trend, if it continues unabated, could result in certain socio‐economic and environmental consequences in the region in particular, and to Ethiopia in general. Groundwater inundation or salty water intrusion, for example, might occur in the area in the near future, thereby affecting the sustainability of regional irrigated agriculture. The lake has the potential to inundate the surrounding region (Matahara Sugar Estate; towns of Fantalle and Matahara) and might connect with the Awash River during the next 10–15 years. This would affect downstream irrigation developments in the Awash Basin and the livelihoods of people that depend on the basin’s water resources. The overall findings of this study emphasize the need to adopt mitigation measures before the lake expansion results in irreversible damage to the region or the basin.     

Spatial and temporal distributions of Dreissena spp. veligers in Lake Huron: Does calcium limit settling success?

The larval stage of invasive Dreissena spp. mussels (i.e., veligers) are understudied despite their seasonal numerical dominance among plankton. We report the spring and summer veliger densities and size structure across the main basin, North Channel, and Georgian Bay of Lake Huron, and seek to explain spatiotemporal variation. Monthly sampling was conducted at 9 transects and up to 3 sites per transect from spring through summer 2017. Veliger densities peaked in June and July, and we found comparable densities and biomasses of veligers between basins, despite differences in density of juvenile and adult mussels across these regions. Using a generalized additive model to explain variations in veliger density, we found that temperature, chlorophyll a, and nitrates/nitrites were most important. We generated an index of veliger attrition based on size distributions that revealed a higher rate of attrition in the North Channel than the rest of the lake. A logistic model indicated a threshold calcium concentration of around 22 mg/L was necessary for veligers to survive to larger sizes and recruit to their juvenile and benthic adult life stages. Improved understanding of factors that regulate the production and survival of Dreissena veligers could improve the ability of managers to assess future invasion threats as well as explore potential control options.     

严寒地区冬季农宅室内燃烧污染及相关性

为了解严寒地区冬季农宅室内空气污染的现状,对哈尔滨附近两个村10户农宅室内污染物PM2.5、PM₁₀、CO、CO₂、SO₂、NO_x、TVOC和NH₃进行了现场测试,并分析了其相关性．结果表明:PM2.5、PM₁₀、CO、CO₂、SO₂和NO_x污染严重,超标率分别为93％、75％、62％、23％、99％和64％,是室内主要的污染物;PM₁₀与PM2.5,PM2.5与CO之间皆显著线性相关,SO₂与CO₂、NO_x与SO₂之间皆线性相关;通过室内污染物间的相关性分析,提出了严寒地区冬季农宅室内空气品质主要检测指标和简易测试方法．     

Comparison between required clothing insulation and that actually worn by workers exposed to artificial cold

Required Clothing Insulation (IREQ) is a new thermal index submitted to the International Organisation for Standardisation (ISO) for discussion. It is designed to prevent general body cooling and is based on an analysis of heat exchanges. The thermal clothing insulation actually worn (lcl) is estimated using a new method, also submitted to ISO.

IREQ of 54 workers exposed to artificial cold (air temperature between −30° C and +10° C) was compared with lcl actually worn by these workers. The results of the present study show that, on average, the workers choose accurately lcl they need if their IREQ is below and up to 1·5 clo. Moreover, these workers prefer to wear garments which provide them with thermal comfort. If IREQ of workers is higher than 1·5–2 clo (i e, workers exposed to −20° C), it is difficult for them to increase their thermal insulation with additional garments. Although their lcl is not sufficient, there is no risk of gradual body cooling because of their continuous time exposure (CTE) which is shorter than the calculated Duration Limited Exposure (DLE). On the other hand, Wind Chill Index (WCI), which is proposed to prevent local cooling, is better adapted to prevent cold injuries than physiological thermal strain; for example, impairment of manual dexterity cannot be prevented with this index.     

A cost‐effective model for the gasoline blend optimization problem

Gasoline blending is a critical process with a significant impact on the total revenues of oil refineries. It consists of mixing several feedstocks coming from various upstream processes and small amounts of additives to make different blends with some specified quality properties. The major goal is to minimize operating costs by optimizing blend recipes, while meeting product demands on time and quality specifications. This work introduces a novel continuous‐time mixed‐integer linear programming (MILP) formulation based on floating time slots to simultaneously optimize blend recipes and the scheduling of blending and distribution operations. The model can handle non‐identical blenders, multipurpose product tanks, sequence‐dependent changeover costs, limited amounts of gasoline components, and multi‐period scenarios. Because it features an integrality gap close to zero, the proposed MILP approach is able to find optimal solutions at much lower computational cost than previous contributions when applied to large gasoline blend problems. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3002–3019, 2016     

Methodologies for hazard analysis and risk assessment in the petroleum refining and storage industry — Part I

The report briefly describes the consecutive steps in the identification, assessment and comparison of hazards and associated risk. These techniques can be helpful in setting the priorities for the decision on measures to reduce risk. When quantifying risk for the comparison of alternative cases, the use of a consistent data base is stressed. It is pointed out that the risk assessment techniques described in the report, although potentially valuable tools for improving overall safety performance, have shortcomings particularly in dealing with human factors. A glossary is appended to define terms as they are used in this report and a list of recommended further reading is included. Part II will appear inFire Technology, November 1984. Reference: CONCAWE's Ad-Hoc Risk Assessment Group; “Methodologies for Hazard Analysis and Risk Assessment in the Petroleum Refining and Storage Industry”, Fire Technology, Vol. 20, No. 3, August 1984, p. 23.