OBSERVATIONS ON ESTUARINE FLUID MUD ENTRAINMENT

I. INTRODUCTIONPrediction of mud bed erosion by forcing due to tidal currents usually requires a numerical solution of the advection--dispersion equation for sediment mass transport. Key role is of course played inthis by the bottom boundary conditions defining erosion and deposition fluxes. The issue of erosion isbriefly considered here. noting that it is customary to calculate the rate of erosion as a function of thebed shear stress in excess of the erosion shear strength of the bed (Me…     

Optimization of nutrient component for diesel oil degradation by Rhodococcus erythropolis

A novel bacterium T7-2 was isolated from the oil-polluted sea-bed mud of Bohai Sea, northern China, which can degrade diesel oil at 15 °C. This bacterium was identified as a strain of Rhodococcus erythropolis according to its 16S rDNA gene. In order to enhance degradation efficiency, a five-level, three-factor central composite design was employed to optimize the nutrition supplied to artificial seawater. The results indicate that a supplement of 2.53 g (NH₄)₂SO₄ L⁻¹, 2.75 g Na₂HPO₄ L⁻¹ and 0.01 g yeast extract L⁻¹ to artificial seawater increases the degradation rate from 12.61% to 75% within 7 d.     

A computer program for flow-log analysis of single holes (FLASH)

A new computer program, FLASH (Flow-Log Analysis of Single Holes), is presented for the analysis of borehole vertical flow logs. The code is based on an analytical solution for steady-state multilayer radial flow to a borehole. The code includes options for (1) discrete fractures and (2) multilayer aquifers. Given vertical flow profiles collected under both ambient and stressed (pumping or injection) conditions, the user can estimate fracture (or layer) transmissivities and far-field hydraulic heads. FLASH is coded in Microsoft Excel(5) with Visual Basic for Applications routines. The code supports manual and automated model calibration.     

Placing identity: interviews with Hong Kong Chinese immigrants in Britain and Canada

"This paper explores the ?borderline community of migration'.... The placing of migrant identities is examined in the context of Hong Kong immigrants in Britain and Canada. Changes in identity and the meaning of the multiplicity of migrant identities are explored through interview material. The tensions between the multiple facets of migrants' identities reflect the sociopolitical relationships within and between places. The resolution of these tensions is partially revealed in the hybridity and fluidity of migrants' articulation of their identities, whilst maintaining a primary identification with their culture of origin."     

Simulation of Stress Distribution around Tunnels and Interaction between Tunnels Using an Elasto-plastic Model

This article presents a computer simulation of stress distribution around tunnels and interaction between tunnels using an elasto-plastic model. A finite element method using ANSYS software has been used for the analyses of one and two tunnels at different overburden depths with different separating distances between the tunnels. The results of numerical analyses indicate that stress distribution and stress concentration around the tunnels vary with the overburden depths. It is found that the coefficients of stress concentration for elasto-plastic medium are smaller than those for elastic one by 1.9%. Furthermore, the interaction between the two tunnels rapidly decreases with the increase of separation distance between them. In addition, for quantitatively describing the interaction between the two tunnels, a critical separation distance is introduced. The critical separation distances between the two tunnels at different overburden depths are 8 m, 12 m, and 14 m respectively. This fact is very important and essential for the design of mining tunnels and to ensure safety in tunnel engineering.     

Measuring the ecological integrity of an industrial district in the Amazon estuary, Brazil

The aim of the present study is to provide information on the ecological integrity of an industrial district located in the estuary of Pará River (Amazon estuary), by applying a selection of fish based multimetric indices of ecosystem integrity: Abundance Biomass Comparation (ABC); Biological Health Index; Estuarine Fish Community, Transitional Fish Classification and Estuarine Biotic Integrity Indexes. To evaluate the impacts of the industrial area and cargo terminal, three areas were considered: Zone 1, (maximum impact), Zone 2 (median risk) and Zone 3 (reference area). All the biological indices used were considered to be excellent indicators of the ecological integrity of the different sectors of the study area and were especially effective for the demonstration of the critical alterations of the fish community of Zone 1 and Zone 2. The simultaneous use of different indices family, with different assumptions, did strengthen the results enhancing the confidence in the diagnostic.     

多种评价方法应用于天津核桃主产区的土壤环境质量评价

以天津市核桃主产区土壤和核桃为研究对象,分析了土壤重金属元素Cd、Hg、Pb、As、Cr、Zn和Cu的含量特征,选用内梅罗指数法、地累积指数法和污染负荷指数法等3种方法评价了土壤环境质量,并分析了核桃食用安全性.结果表明:研究区土壤样品中Cd、Hg、Pb、As、Cr、Zn和Cu的平均含量分别为0.19×10-6、0.06×10-6、24.lx 10-6、11.9×10-6、75.5×10-6、78.9×10-6和30.6xl0-6,Cd、Hg 和As 平均值均超过了天津市背景值,而且Cd 和Cu 分别有11.7%和1.7%的样品点位超过风险筛选值.根据内梅罗综合指数法可以得出,研究区土壤环境质量总体较好,但由地累积指数与污染负荷指数评价发现,研究区存在人为原因引起的土壤重金属积累情况,且污染点位均匀分布于研究区.核桃样品中Cd、Hg、Pb、As和Cr平均含量分别为0.003×10-6、0.004×10-6、0.044×10-6、0.043×10-6和0.760×10-6,均满足食品安全标准要求.