Natural aggregates in the performance and durability of concrete: chemical characteristics     

Peter G. Fookes  Mike J. Walker 《Geology Today》2012,28(1):20-25

This article continues from the earlier feature in Geology Today (2011, v.27, n.4) and looks at the influence of chemical reactivity within concrete due to the presence of unsound aggregates or deleterious material incorporated in the aggregate used in the concrete mix. Some of the more disruptive problems from chemical unsoundness come from the presence of chlorides, which cause rusting in reinforced concrete or, sulphate attack from ground waters. Both of these reactions are relatively common in Britain. Alkali–silica reactions with aggregates and cement is not too prevalent in Britain but can be very prevalent and disruptive elsewhere in the world.  相似文献   

Field Comparison of Micropurging vs. Traditional Ground Water Sampling     

Peter M. Kearl  Nic E. Korte  Mike Stites  Joe Baker 《Ground Water Monitoring & Remediation》1994,14(4):183-190

Micropurge sampling of ground water wells has been suggested as a possible replacement to traditional purge and sample methods. To compare methods, duplicate ground water samples were collected at two field sites using iraditional and micropurge methods. Samples were analyzed for selected organic and inorganic constituents, and the results were compared statistically. Analysis of the data using the nonparametric sign test indicates that within a 95 percent confidence interval, there was no significant difference between the two methods for the site contaminants and the majority of analytes. These analytical results were supported by visual observations with the colloidal borescope, which demonstrated impacts on the flow system in the well when using traditional sampling methods. Under selected circumstances, the results suggest replacing traditional sampling with micropurging based on reliability, cost, and waste minimization.  相似文献   

Coseismic crustal deformation from microseismicity in the Patras area, western Greece     

Nikolaos S. Melis  Paul W. Burton  Mike Brooks 《Geophysical Journal International》1995,122(3):815-836

  相似文献   

River stabilisation due to changing climate and vegetation during the late Quaternary in western Tasmania, Australia     

Gerald C. Nanson  Mike Barbetti  Gillian Taylor 《Geomorphology》1995,13(1-4)

The Stanley River in western Tasmania, Australia, contains sub-fossil rainforest logs within the channel and floodplain. Of the more than 85 radiocarbon dates obtained, all but 3 date from 17 ka to the present and permit an interpretation of fluvial and related environmental changes over this period. Particular attention is focused on the interactive relationship between the river and its riparian rainforest. Following the Last Glacial Maximum, the Stanley River was a laterally active gravel-load system reworking most of its valley floor in the upstream reaches. With ameliorating conditions at the end of the Pleistocene, climate became less seasonal and flow regimes less energetic. Huon pines already present in the catchment, re-asserted themselves in the form of dense tree cover along the river banks and floodplains with basal floodplain deposition shifting from gravels to coarse sands and granules. By about 3.5 ka, a further change in climate reduced stream discharges substantially. As a result the channel reduced in size, transported finer sediment, became laterally stable, and the floodplain accreted with overbank deposits of sand and silt. Huon pines falling into the channel formed obstructions of woody debris, some surviving for 2 ka. These have reduced stream power and boundary shear stress, further contributing to channel stability. Generational sequences of Huon pines on the river banks, some extending back 1–2 ka, are additional evidence of this stability. Since the Pleistocene, changing climate and the re-establishment of dense riparian rainforest appear to have stabilised the river channels and floodplains of western Tasmania.  相似文献   

Quantitative fluorescence microscopy: by F.W.D. Rost. Cambridge University Press, 1991, 236 pp.     

Mike Barer 《International Journal of Coal Geology》1994,26(3-4)

  相似文献   

Geomagnetic secular variation from recent lake sediments,ancient fireplaces and historical measurements in southeastern Australia     

C.E. Barton  Mike Barbetti 《Earth and Planetary Science Letters》1982,59(2):375-387

Compilations of historical observations, archaeomagnetic data from ancient fireplaces and palaemagetic results from short cores of sediment from lakes in southeastern Australia, particularly Lake Keilambete, provide a detailed record of the geomagnetic secular variation during the last 3000 years. The independent sets of data are in good agreement if the radiocarbon time scale for the lacustrine record is about 450 years too old. The error is attributed to systematic incorporation of ancient carbon into the lake floor sediments, mainly through erosion of sediment on the crater walls at times of low water level. A significant lag between deposition and the acquisition of stable magnetic remanence is ruled out. Inclination has been abnormally steep during the last 500 years but remained fairly close to the axial dipole field value prior to that. During the last 1000 years the predominant sense of looping of the magnetic vector corresponds to westward drift of the nondipole field. Secular variations on a time scale of ～ 100 years can be resolved by the lacustrine record.  相似文献   

The Western Pearl River Delta: Growth and Opportunities for Cooperative Development with Hong Kong by Y. M. Yeung,Shen Jianfa,and Zhang Li     

Mike Rudibaugh 《The Professional geographer》2007,59(3):397-398

  相似文献   

利用AutoPrep技术抑制型电导离子色谱法检测土壤中碘     

刘肖  史亚利Archava Siriraks Mike Kinderman 《岩矿测试》2007,26(6):446-450

利用AutoPrep自动样品前处理技术，对土壤燃烧吸收液进行在线预浓缩，抑制型电导进行检测，建立了一种全新思路的检测土壤样品中碘的方法。选择亲水性非常强的氢氧化物选择性IonPac AS16阴离子交换色谱柱，淋洗液发生装置在线产生KOH进行等梯度淋洗，抑制型电导检测。结果表明，对于土壤燃烧吸收液中碘离子的测定，方法检出限（S／N=3）可达1．2μg/L，线性相关系数为0．9998，方法精密度（RSD，n=7）为1．161％～4．566％，回收率在90．6％～100．8％。采用AutoPrep电导检测和脉冲安培检测离子色谱法测定不同土壤样品中的碘，两种方法的检测结果基本一致。方法在提供了稳定的系统空白的同时，还具备自动化程度高、操作简单、重现性好、灵敏度高、系统稳定、节约时间、成本低廉和对环境友好等多方面特点，适合于大批量土壤普查中碘的分析。  相似文献   

Space exploration and the RAS     

Mike Hapgood  Ian Crawford 《Astronomy& Geophysics》2007,48(6):6.9-6.10

Mike Hapgood and Ian Crawford assess the relevance of the BNSC UKSEWG Report for the Royal Astronomical Society.  相似文献   

Editorial Note     

Mike Parnwell  & Jonathan Rigg 《Singapore journal of tropical geography》2001,22(3):205-211

  相似文献