化学品分类管理策略与安全预警机制的建立

从全球化学品统一分类和标签制度（GHS）背景出发,结合GHS中化学品危险性分类及国内外化学品分类管理的实际情况,提出了适用于分类管理的19个危险化学品类别及化学品分类管理的整体思路;从分类别管理角度提出分类管理的重点为物理危害的11个类别,健康危害的2个类别,环境危害的1个类别;从管理环节角度提出分类管理的重点是生产、使用、储存、运输环节。在此基础上,进一步提出基于危险化学品登记数据建立安全预警机制的策略。     

汶川地震余震地震动衰减关系研究

2008年汶川8.0级特大地震发生后,又发生了多次余震,震区的固定台站和流动台站因此获取了上万条MS3.3～6.4级地震动观测记录。地震记录显示这些余震的震中距和震级分布比较均匀,为建立地震动衰减关系奠定了较好的数据基础。本文基于汶川地震MS3.3～6.4震级范围内、震中距小于150 km区域范围的余震观测数据进行了统计回归分析,建立了汶川地震余震(MS≤6.4)的衰减关系模型,并对地震动加速度峰值(PGA)给出了具体的衰减关系表达式。     

基于资源环境承载力的全国造纸工业类型区划分研究

本文从造纸行业特征、资源消耗、污染物排放等方面入手,结合区域资源环境承载力,分析行业发展可能带来的环境污染问题.分析造纸行业发展与其所需主要资源间的空间布局关系,明确选定行业发展的资源、环境和生态制约条件.结合造纸行业特点,从环境约束、生态约束和资源约束入手,构建其环境管理类型区划分的指标体系;采用层次分析法、灰色定权聚类分析等方法对分区数据进行必要处理,采用二维判断矩阵法等方法进行环境管理类型区划分,对实施针对造纸行业分区域、分类别、差别化的环境管理提供了决策依据和方法基础.     

Dimensional analysis and scaling in mechanical mixing for fabrication of metal matrix nanocomposites

For a successful enhancement of mechanical properties of metal matrix nanocomposites, a homogeneous nanoparticle dispersion and distribution in the solidified metal is required. Mechanical mixing can be used for initial break-up of agglomerates, and its study can be simplified with dimensional analysis. Using this technique, mixing time and vortex height were assessed while varying fluid properties, impeller angle, and angular speed. Three relevant dimensionless numbers were recognized: the Reynolds (Re), Froude and Galilei (Ga) numbers. Based on blade and impeller shaft angles, a modified Froude number (Fr*) was defined. These parameters were calculated experimentally, varying angular speed from 200 to 1000 rpm for three different impeller angles: 0°, 15° and 30°. This procedure was performed with three fluids: water, and two aqueous glycerin solutions (25% and 50% by volume). Digital images were taken and processed to measure vortex height. Mixing time was measured for water at 0° impeller angle, angular speed ranging from 200 to 1200 rpm. Results showed an optimal dimensionless mixing time with respect to Re. A linear relationship was found between dimensionless vortex height and Fr*. The first had a second order polynomial relationship with the product ReFr*, regardless of impeller angle. This relationship, together with the Ga, specific for each fluid, allows scaling the results to other fluids such as molten pure aluminum. This study allows experimenting in simpler systems that involve transparent fluids, room temperature and low cost, to then elaborate a prediction of vortex height in fluids where measurements are difficult and costly, such as molten metals.     

Establishment of facultative sexuals

The existence of sex is one of the major unsolved problems in biology. We use computer simulations to model conditions in which sex may first become established. We develop an individual-based population model and show that a hypothetical facultative sex gene can fix, provided that the initial cost is low. It is demonstrated that the equilibrium fitness in the population increases with increasing population size and decreasing mutation rate. The probability of the establishment of the sex gene is found not to be directly related to the fitness difference between the asexual and sexual populations. This change in fitness on changing the parameters of the model is investigated.     

Health implications of radon distribution in living rooms and bedrooms in U.K. dwellings--a case study in Northamptonshire

Environmental radon exposure of residents of domestic premises in the United Kingdom (UK) and elsewhere in Europe is estimated on the basis of the measured radon concentrations in, and the relative occupancies of, the principal living room and bedroom. While studies on radon concentration variability in the individual units in apartment blocks in various countries have been described, little data has been reported on variability in two-storey single-family dwellings, and the majority of extant studies consolidate living room and bedroom data early in the analysis. To investigate this further, detailed analysis was made of radon concentration data from a set of thirty-four homes situated in areas of Northamptonshire known to exhibit high radon levels. All homes were of typical UK construction of brick/block/stone walls under a pitched tile/slate roof. Approximately 50% of the sample were detached houses, the remainder being semi-detached (duplex) or terraced (row-house). Around 25% of the sample possessed cellars, while 12% were single-storey dwellings (bungalows), reflecting the typical incidence of this type of dwelling in England. In the two-storey homes, all monitored bedrooms were on the upper floor. Distribution of the ratios of bedroom/living room radon concentrations (BR/LR ratio) in individual properties was left-skewed (mean 0.67, median 0.73, range 0.05-1.05) with a tail extending to just above 1.0. The mean is consistent with the outcome of earlier extensive studies in England, while the variability depends principally on the characteristics of the property, and not on seasonal factors. In a small set of homes, the BR/LR ratio was anomalously low, (mean 0.3). BR/LR ratios in single-storey homes clustered around a value of 1.0, indicating that house design, rather than lifestyle, is the dominant factor in determining bedroom radon concentrations. Homes with higher mean annual radon concentrations showed lower BR/LR ratios, supporting our proposal that, in some homes, radon emanation from building materials may comprise a significant component of the overall radon level.     

On the radiocesium carbonate barrier in organics-rich sediments of Lake Juodis, Lithuania

Radiocesium vertical profiles in organics-rich sediments of running shallow eutrophic Lake Juodis (Lithuania) were studied in relation to seasonal variations of vertical profiles (in water column and sediments) of standard variables (pH, redox potential, temperature, oxygen concentrations, conductivity). It is shown that the sedimentation rate, radiocesium mobility and its vertical profiles in sediments are controlled by the vital cycle (processes of the growth, accumulation and decomposition) of green algae covering the main bottom areas of the lake. It is also shown that calcite deposits are formed in the shallow bottom areas that are oxygenated throughout the year because of the photosynthetic activity of the green algae covering the sediment. Formation of the calcite coatings on freshly accumulated organics is remarkable for causing elevated densities of sediment solids in the upper part of the respective vertical profiles. These calcite deposits behave as a barrier for radiocesium backward flux to the bottom water making the respective bottom areas a radionuclide sink. Together with the jelly-structured sediments lying below these deposits, the calcite preserves the shape of the primary radiocesium vertical profiles formed due to free-ion diffusion after the deposition event. It was determined that bottom areas anaerobic in winter are the main radiocesium source in the water column and cause characteristic radiocesium redistribution in surface sediments.     

The transfer of 137Cs and 90Sr from feed to rabbits

Radiological assessment of the impact of nuclear weapons testing on the local population in the Semipalatinsk Test Site (STS) requires comprehensive site-specific information on radionuclide behaviour in the environment. However, information on radionuclide behaviour in the conditions of the STS is rather sparse and, in particular, there are no data in the literature on parameters of radionuclide transfer from feed to rabbit products which have been identified as contributors to internal dose to the inhabitants. The transfer of (137)Cs and (90)Sr to rabbit meat was studied under laboratory conditions in a controlled experiment with 32 locally bred rabbits maintained in the Kazakh Agricultural Research Institute. The equilibrium transfer coefficients for (137)Cs and (90)Sr from feed to rabbit meat were estimated to be 0.4 d kg(-1) and 0.15 d kg(-1), respectively. The biological half-lives were estimated to be 0.1 d for (137)Cs and 0.14 d for (90)Sr. Whereas for (137)Cs the distribution in the body is relatively homogeneous, there are large differences between the organs and tissues for (90)Sr for which, as expected, the highest concentrations were found in bone.     

The transfer of 239/240Pu to cow milk

In summer 1993 we measured the transfer of (239/240)Pu to milk from herbage from a pasture located 5 km from the Chernobyl nuclear power plant. In one treatment cows were allowed to graze freely on the pasture. In a second treatment, cows were fed herbage collected from the pasture in stalls. The milk transfer coefficient; F(m) did not vary significantly between treatments and the mean value of 7.5x10(-6)d l(-1) was higher than previously reported values. Despite many values of F(m) for Pu in the literature we identified few relevant original data sets. Transfer coefficient values for Pu are only appropriate when used in conjunction with a specified time period or an appropriate model which allows for the biological half-life. We recommend for screening purposes an F(m) value of 1x10(-5)d l(-1) for Pu, with an order of magnitude lower value being appropriate for cows which are only exposed for one grazing season.     

Distribution of organotin compounds in the bivalves of the Aegean Sea, Greece

Five bivalve species--Mytilus galloprovinciallis (Mediterranean mussels), Venus gallina (stripped venus), Modiola barbatus L. (bearded horse mussels), Pecten jacobeus (scallops) and Callista chione (hard clams)--were collected from seven areas in Aegean Sea, Greece, between August 2001 and January 2003 and analyzed for organotins (OTs). The concentrations (as geometric means) found were 17.1 ng g-1 for tributyltin (TBT), 18.8 ng g-1 for dibutytltin (DBT), 7.8 ng g-1 for monobutyltin (MBT) and 13.0 ng g-1 for triphenyltin (TPhT) (wet weight), which are at similar or lower levels than those reported worldwide. Studying OTs distribution between different bivalve species, lower concentrations were observed in mediterranean mussels, possibly due to their growth in water column (grown on sea net pens in mussel farms), in contrast to the free-ranging species, collected from fishing grounds. Concentrations of the OTs in the examined bivalves varied seasonally.