Environmental levels of sediment-associated tri-n-butyltin chloride (TBTCl) and ionic regulation in flounders during seawater adaptation

The effects of exposure to sediment-associated tri-n-butyltin chloride (TBTCl) were examined in the euryhaline European flounder, Platichthys flesus (L.). The effects were quantified by measuring the changes in sodium efflux; Na⁺/K⁺-ATPase activity; and the numbers, areas, and distribution of chloride cells in the gills of freshwater-adapted fish, following a rapid transfer to seawater. Following the transfer to seawater, the Na⁺/K⁺-ATPase activity and the sodium efflux were significantly increased in the control group but remained unchanged in the TBTCl-exposed group. The normal morphological changes to the gill epithelium associated with seawater adaptation, which involve chloride cell distribution, took place in the control group but were significantly inhibited or delayed in the TBTCl group. The results presented in this study lead to the conclusion that environmental concentrations of tri-n-butyltin chloride in sediments are capable of significantly disrupting both the physiological and the morphological components of iono-regulatory functions of an estuarine flatfish.     

Organic aerosol characterization by complementary measurements of chemical bonds and molecular fragments

Organic aerosol chemical markers from normalized concentrations of independent measurements of mass fragments (using Aerosol Mass Spectrometry, AMS) are compared to bond-based functional groups (from Fourier Transform Infrared spectroscopy, FTIR) during eight field projects in the western hemisphere. Several field projects show weak correlations between alcohol group fractions and m/z 60 fractions, consistent with the organic hydroxyl groups and the fragmentation of saccharides, but the weakness of the correlations indicate chemical differences among the relationships for ambient aerosols in different regions. Carboxylic acid group fractions and m/z 44 fractions are correlated weakly for three projects, with correlations expected for aerosols dominated by di-acid compounds since their fragmentation is typically dominated by m/z 44. Despite differences for three projects with ratios of m/z 44 to m/z 57 fragments less than 10, five projects showed a linear trend between the project-average m/z 44 to m/z 57 ratio and the ratio of acid and alkane functional groups. While this correlation explains only a fraction of the fragment and bond variability measured, the consistency of this relationship at multiple sites indicates a general agreement with the interpretation of the relative amount of m/z 44 as a carboxylic acid group marker and m/z 57 as an alkane group marker.     

滑坡动态变形过程的综合研究方法

影响滑坡变形破坏过程的因素具有复杂性和多变性，要合理评价和预测滑坡的动态发展过程，深入的地质原型调查是基础，地质分析不仅能为其它分析方法的正确使用提供资料，而且能直接对滑坡的变形破坏发展过程作出定性的判断。在此基础上建立力学模型，采用数学力学理论进行定量计算和反演分析，可进一步从本质上去把握滑坡变形破坏的发展规律。本文通过介绍李家峡水电站Ⅱ号滑坡的研究实践，说明了采用定性地质分析与定量力学计算相结合的研究方法揭示滑坡变形破坏动态过程的有效性。     

Urban growth management in Jeddah

The towns and cities of Saudi Arabia have been subjected to sustained growth pressures since the transformation of the country's economy following the discovery of oil in the Eastern Province of the Kingdom. The rapid growth which has been experienced has created major problems for the central and local government agencies responsible for planning and managing urban growth. The experience of Jeddah, one of the major cities in Saudi Arabia, is described and the problems of planning and managing its growth are analysed. Weaknesses relating to the structure of the planning system are identified, as are major difficulties in relation to the quality and quantity of professional staff. Recent attempts to improve the operation of the planning system are described and evaluated.     

滨海软土中爆炸冲击对盾构隧道的影响研究∗

随着地下工程与城市管网的布设日益发展,在规划设计阶段往往需要考虑潜在发生的安全事故影响,确定安全距离。利用ANSYS/LS-DYNA有限元软件,结合天津滨海新区饱和软土特点,分析了可能发生的燃气管线爆炸所产生的冲击荷载对土中埋置盾构隧道的结构安全影响。运用有限元数值模拟,得到了隧道与管线的间距—隧道结构振速峰值的曲线关系;通过对标相关规范的振速限制,得到不同燃气压力下隧道—管线的安全避让距离关系。结果表明:随着燃气管道压强的增大,隧道—管线的安全避让距离呈现先增大后平稳的趋势。结论对于爆破与防护工程设计均具有重要的参考价值。     

Comparing Green and Grey Infrastructure Using Life Cycle Cost and Environmental Impact: A Rain Garden Case Study in Cincinnati,OH

Green infrastructure (GI) is quickly gaining ground as a less costly, greener alternative to traditional methods of stormwater management. One popular form of GI is the use of rain gardens to capture and treat stormwater. We used life cycle assessment (LCA) to compare environmental impacts of residential rain gardens constructed in the Shepherd's Creek watershed of Cincinnati, Ohio to those from a typical detain and treat system. LCA is an internationally standardized framework for analyzing the potential environmental performance of a product or service by including all stages in its life cycle, including material extraction, manufacturing, use, and disposal. Complementary to the life cycle environmental impact assessment, the life cycle costing approach was adopted to compare the equivalent annual costs of each of these systems. These analyses were supplemented by modeling alternative scenarios to capture the variability in implementing a GI strategy. Our LCA models suggest rain garden costs and impacts are determined by labor requirement; the traditional alternative's impacts are determined largely by the efficiency of wastewater treatment, while costs are determined by the expense of tunnel construction. Gardens were found to be the favorable option, both financially (~42% cost reduction) and environmentally (62‐98% impact reduction). Wastewater utilities may find significant life cycle cost and environmental impact reductions in implementing a rain garden plan.     

澜沧江梯级水电站库区水环境时空差异性研究

根据2008年1—12月澜沧江下游的漫湾水电站、大朝山水电站库区的水质监测资料,对水环境时空差异性进行了分析,结果表明:两库区水质特征变化趋势比较相似,季节性变化明显,两库区水体有机污染程度小,水体氮磷含量较高,属于中—富营养水平,总氮在秋季最高,冬季最低,总磷在夏秋季最高,春季最低。梯级水坝的形成对水体中总氮含量、有机污染的累积效应不明显。     

脉冲激光发射模块电磁屏蔽效能仿真分析

目的 提高脉冲激光发射模块的电磁兼容性。方法 基于腔体的电磁屏蔽机理,使用HFSS软件,建立脉冲激光发射模块腔体模型,以电磁敏感度、电磁干扰2个方面对腔体电磁屏蔽效能进行仿真分析。结果 设计的双层屏蔽腔体在电磁波辐照频率为1~100 kHz时,屏蔽效能达到28 dB;电磁波辐照频率为0.2~18 GHz时,屏蔽效能达到47 dB。结论 当电磁波辐照频率在1~100 kHz时,腔体的屏蔽效能随频率的增加而增大。辐射源外部激励时,双层屏蔽腔体使用外层铁内层铜屏蔽效能较高。电磁波辐照频率在0.2～18 GHz时,腔体的屏蔽效能随频率的增大而减小,且发生了谐振效应。当腔体厚度相等时,双层屏蔽的屏蔽效能高于单层屏蔽。使用电缆连接器代替孔洞进行信号传输时,腔体屏蔽效能增加。     

Regional assessment of plant growth problems for colliery spoil reclamation

Possibilities for greater variation in landscaping during the reclamation of derelict colliery spoil heaps and the potential of a regional approach to the survey of revegetation problems are introduced. A survey method for assessing plant growth problems is described which incorporates rapid measurement of physical and chemical constraints to plant growth and which uses bioassay trials as an index of plant growth potential. The use of the survey method on 34 closed and disused sites in the Barnsley and South Yorkshire areas of the National Coal Board is outlined and suggestions for the incorporation of such data in recommendations for the reclamation of individual sites are made.