Geostatistical analysis in weathering studies: case study for Stanton Moor building sandstone     

Jennifer M. McKinley  Patricia Warke  Christopher. D. Lloyd  Alastair H. Ruffell  Bernard J. Smith 《地球表面变化过程与地形》2006,31(8):950-969

Geostatistical techniques for spatial prediction and spatial simulation have been used in an innovative application to the study of weathering of natural building stone. The study investigates the differences in the spatial variation of permeability characteristics between fine‐ and coarse‐grained Stanton Moor building sandstone. Non‐destructive permeability measurements, using an unsteady‐state Portable Probe Permeameter, were made on three adjacent faces of two cubic blocks representative of fine‐ to medium‐grained and medium‐ to coarse‐grained Stanton Moor Sandstone. The findings provide greater understanding in the investigation of the durability characteristics of the Stanton Moor Sandstone and show that the spatial distribution and variability of permeability is more important in predicting the overall strength and weathering properties than mean permeability and absolute minimum and maximum values. The results suggest that both primary textural characteristics (such as grain size) and extent of cementation appear to be important factors in determining the overall durability properties of Stanton Moor Sandstone as a building stone. Geostatistical analysis has been shown to be an important tool in the characterization of spatial variation for the investigation of weathering of building stones. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Discussion of “In absurdum: long-term predictions and nuclear waste handling”: By N.A. Mörner (Vol. 61, pp. 75–82)     

I. G. McKinley  R. Munier   《Engineering Geology》2003,68(3-4):401-403

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Relative timing of tropical storm lifetime maximum intensity and track recurvature     

J. L. Evans  K. McKinley 《Meteorology and Atmospheric Physics》1998,65(3-4):241-245

Summary An intriguing picture is emerging of coupled track and intensity links in tropical cyclones. Since recurvature represents a dramatic track shift, recurving tropical storms are isolated in this study and their time of maximum lifetime intensity is compared to their time of recurvature. Thirty-one percent of all western North Pacific tropical storms and 28% of all such storms in North Atlantic recurve. Seventeen years of track and intensity data for recurving tropical cyclones in these basins are examined here.The overwhelming majority (80%) of western North Pacific tropical storms (including typhoons) reach their lifetime maximum intensity prior to recurvature. More than 45% of all recurving storms have coincident recurvature and lifetime maximum intensity, with weaker tropical storms clearly more likely to reach peak intensity at recurvature than strong systems.Inspection of tropical storm intensity and track data for North Atlantic systems reveals few clear patterns. The most robust observation to be made here is that the majority of these systems reach their peak intensity prior to recurvature. Exclusion of landfalling extratropically transforming tropical cyclones from this sample greatly reduces the number of systems, making the significance of any results questionable.With 2 Figures  相似文献   

Laboratory Column Experiments Using Polymer Mats to Remove Selected VOCs, PAHs, and Pesticides from Ground Water   总被引：1，自引：0，他引：1  

Bradley Mark Patterson  Gregory Bruce Davis  Allan James McKinley 《Ground Water Monitoring & Remediation》2002,22(2):99-106

Large-scale column experiments were undertaken to evaluate the potential of polymer mats to remove selected volatile organic compounds, polycyclic aromatic hydrocarbons, and pesticides (atrazine and fenamiphos) from ground water and potentially to act as permeable reactive barriers in contaminated ground water environments. The polymer mats, composed of interwoven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2 m long flow-through columns. The polymer mats proved efficient in physically removing (stripping) benzene and naphthalene from contaminated water. Removal efficiencies for both these compounds from an aqueous phase flowing past a polymer mat were 75% or greater. However, for atrazine and fenamiphos, removal efficiencies were 5% or less, probably as a result of their lower Henry's law constants and possibly lower polymer diffusion coefficients.
These experiments indicate that, at least for relatively volatile compounds, polymer mats can provide a remediation technique for the removal of organic compounds from contaminated water. Application of this technique may be well suited as a longer-term, semipassive strategy to remediate contaminated ground water, using natural ground water flow to deliver contaminated ground water to polymer mats engineered as sorption-stripping barriers.
Additional benefits of this technique may include targeted delivery of gaseous chemical amendments, such as oxygen, to enhance aerobic biodegradation and to further reduce any residual concentrations of contaminants.  相似文献   

Reductive biotransformation of Fe in shale-limestone saprolite containing Fe(III) oxides and Fe(II)/Fe(III) phyllosilicates     

Ravi K. Kukkadapu  John M. Zachara  James P. McKinley  Steven C. Smith 《Geochimica et cosmochimica acta》2006,70(14):3662-3676

A <2.0-mm fraction of a mineralogically complex subsurface sediment containing goethite and Fe(II)/Fe(III) phyllosilicates was incubated with Shewanella putrefaciens (strain CN32) and lactate at circumneutral pH under anoxic conditions to investigate electron acceptor preference and the nature of the resulting biogenic Fe(II) fraction. Anthraquinone-2,6-disulfonate (AQDS), an electron shuttle, was included in select treatments to enhance bioreduction and subsequent biomineralization. The sediment was highly aggregated and contained two distinct clast populations: (i) a highly weathered one with “sponge-like” internal porosity, large mineral crystallites, and Fe-containing micas, and (ii) a dense, compact one with fine-textured Fe-containing illite and nano-sized goethite, as revealed by various forms of electron microscopic analyses. Approximately 10-15% of the Fe(III)_TOT was bioreduced by CN32 over 60 d in media without AQDS, whereas 24% and 35% of the Fe(III)_TOT was bioreduced by CN32 after 40 and 95 d in media with AQDS. Little or no Fe²⁺, Mn, Si, Al, and Mg were evident in aqueous filtrates after reductive incubation. Mössbauer measurements on the bioreduced sediments indicated that both goethite and phyllosilicate Fe(III) were partly reduced without bacterial preference. Goethite was more extensively reduced in the presence of AQDS whereas phyllosilicate Fe(III) reduction was not influenced by AQDS. Biogenic Fe(II) resulting from phyllosilicate Fe(III) reduction remained in a layer-silicate environment that displayed enhanced solubility in weak acid. The mineralogic nature of the goethite biotransformation product was not determined. Chemical and cryogenic Mössbauer measurements, however, indicated that the transformation product was not siderite, green rust, magnetite, Fe(OH)₂, or Fe(II) adsorbed on phyllosilicate or bacterial surfaces. Several lines of evidence suggested that biogenic Fe(II) existed as surface associated phase on the residual goethite, and/or as a Fe(II)-Al coprecipitate. Sediment aggregation and mineral physical and/or chemical factors were demonstrated to play a major role on the nature and location of the biotransformation reaction and its products.  相似文献