Low salinity residual ballast discharge and exotic species introductions to the North American Great Lakes

Exotic species introductions to the North American Great Lakes have continued even though ballast water management strategies were implemented in the early 1990s. Overseas vessels that arrive with little or no exchangeable ballast on board have been suspected to be an important source for discharging low salinity ballast containing low salinity tolerant organisms in this region. Residual ballast averaged 18.1+/-13.4 per thousand salinity among 62 samples taken primarily from bottom tanks on 26 vessels that entered the Great Lakes in 1999 and 2000. Sampling of 2-4 tanks each on nine vessels indicated all carried at least one tank of residual ballast of 相似文献   

Practical issues in imaging hydraulic conductivity through hydraulic tomography

Hydraulic tomography has been developed as an alternative to traditional geostatistical methods to delineate heterogeneity patterns in parameters such as hydraulic conductivity (K) and specific storage (S(s)). During hydraulic tomography surveys, a large number of hydraulic head data are collected from a series of cross-hole tests in the subsurface. These head data are then used to interpret the spatial distribution of K and S(s) using inverse modeling. Here, we use the Sequential Successive Linear Estimator (SSLE) of Yeh and Liu (2000) to interpret synthetic pumping test data created through numerical simulations and real data generated in a laboratory sandbox aquifer to obtain the K tomograms. Here, we define "K tomogram" as an image of K distribution of the subsurface (or the inverse results) obtained via hydraulic tomography. We examine the influence of signal-to-noise ratio and biases on results using inverse modeling of synthetic and real cross-hole pumping test data. To accomplish this, we first show that the pumping rate, which affects the signal-to-noise ratio, and the order of data included into the SSLE algorithm both have large impacts on the quality of the K tomograms. We then examine the role of conditioning on the K tomogram and find that conditioning can improve the quality of the K tomogram, but can also impair it, if the data are of poor quality and conditioning data have a larger support volume than the numerical grid used to conduct the inversion. Overall, these results show that the quality of the K tomogram depends on the design of pumping tests, their conduct, the order in which they are included in the inverse code, and the quality as well as the support volume of additional data that are used in its computation.     

周口坳陷叶鲁断裂带构造特征及其演化

叶鲁断裂带位于华北克拉通南部,是鲁山-舞阳-阜阳-淮南断裂带的重要组成部分,控制着周口坳陷谭庄、舞阳等凹陷的形成与演化。据钻井、地震剖面解释和平衡剖面分析,在秦岭-大别造山带挤压活动的影响下,叶鲁断裂带在晚侏罗世—早白垩世向NNE方向强烈逆冲,主断层面倾角约37°,伸展率可达-22 m/Ma;晚白垩世—古近纪,周口坳陷处于伸展构造环境,该断裂带发生负反转构造作用。通过三角剪切软件模拟了叶鲁断裂带主断层在周参12井区的构造演化过程。模拟显示主断层形成时的总滑动量约为6 100 m,断层传播量为9 150 m,三角剪切角为150°,p/s值为1.5。     

Physical, chemical and microbiological characterization of the intertidal sediments of Pereque Beach, Guarujá (SP), Brazil

Physical and chemical characteristics of intertidal sediments and their relationships with bacteria and cyanobacteria were analyzed at four stations at Pereque Beach. Granulometric analysis showed that Pereque beach has sediment that is classified as sand. The lowest value of the sediment C/N rates (6.08), mainly due to a higher concentration of organic nitrogen, was found at the northern part of Pereque Beach, where organic matter of marine source was more prominent. In this area, density (9.6x10(6)cells cm(-3)), biomass (1992.04ngC cm(-3)) and activity of bacteria were higher than at the southern end. In contrast, cyanobacteria density varied from 2.0 to 4.0x10(5)cells cm(-3), with biomass and total chlorophyll a of the sediment being higher at the southern part, where there are water input from Pereque River and higher organic matter of continental origin. The variability in the microbial population is discussed in the light of the sediment granulometry, organic matter quality, fresh water inflow and pollution.     

The significance of dilution in evaluating possible impacts of wastewater discharges from large cruise ships

In response to public concerns about discharges from large cruise ships, Alaska's Department of Environmental Conservation (ADEC) sampled numerous effluents in the summer of 2000. The data showed that basic marine sanitation device (MSD) technology for black water (sewage) was not performing as expected. Untreated gray water had high levels of conventional pollutants and surprisingly high levels of bacteria. Both black water and gray water discharges sometimes exceeded state water quality standards for toxicants. The state convened a Science Advisory Panel (the Panel) to evaluate impacts associated with cruise ship wastewater discharges. The effluent data received wide media coverage and increased public concerns. Consequently, legislative decisions were made at the State and Federal level, and regulations were imposed before the Panel completed its evaluation. The Panel demonstrated that following the rapid dilution from moving cruise ships, the effluent data from the Summer of 2000 would not have exceeded water quality standards, and environmental effects were not expected.     

台湾地球物理勘探事业现状

一、地球物理勘探概要地球物理勘探主要归工业技术研究院矿业研究所地球物理应用研究计划小组主管,内分电法勘探、重力勘探、磁法勘探、放射性勘探、地震勘探、遥感技术几个部分,实际以电法勘探及地震勘探为主.勘探内客:电法勘探主要用于矿床及建设基地调查,地震勘探主要用于钻井调查,即通过所谓速度测井(P,P·S)对建设基地的调查,有时也用于隧道、铁路、公路等调查.上述矿业研究所的基础研究中电法勘探一项内,实行水槽试验;在应用研究上以电法与地震勘探作对比研究.地球物理测井则以开发地热为主.     

沸石的热分析

沸石类矿物因具有阳离子交换作用、催化作用及分子筛作用.它作为工业原料、农业原料、以及公害处理材料有多方面利用价值,很值得注意,还有这种矿物在比较低温条件下脱水,产生“沸石水”,这种热的特性也使人深感兴趣.本研究是想通过用差热分析,研究日本国内产斜发涕石(Clinop-tilotite)的热特性,作为探索天然沸石生成状态的一个线索.实验方法将日本岛根县产斜发沸石选纯.在IN、KCI、NaCI、CaCI_2水溶液中进行离子交换,作成K型、Na型、Ca型沸石,然后通过加热使结构发生变化,经化学分析确认已成为所要求的沸石.然后使用“岛津制作所的A30型热分析装置”以至少33毫升/分钟的N_2进行热矢量分析、差热分析,从沸石中存在的U~+、Na~+”、Ca~(2+)的离子比率中求出     

日本1980～2010年宇宙科学技术预测调查

日本科学技术厅计划局,最近将该局所制订1980~2010年间技术预测调查结果,归纳为生命科学,宇宙科学等13领域,将各领域的现状及存在问题,今后展望与技术课题等内容写成报告,于1983年初公开发表。现摘译其中宇宙开发部分于后:     

查干布拉根银氧化矿堆浸试验研究

查干布拉根银矿是黑龙江省地质勘查局七0三队、七0六队经多年勘查发现的大型银矿床，原生矿由国家控制开采，地表银氧化矿允许该局独立开采，独立选冶。怎样选择一个投资少、见效快，即简便、又适合普通地质队现有人力、财力来承担完成，而且能产生一定经济效益的提银方案成为急待解决的问题。