DNAPL Characterization Methods and Approaches, Part 2: Cost Comparisons   总被引：1，自引：1，他引：1  

Mark L. Kram  Arturo A. Keller  Joseph Rossabi  Lome G. Everett 《Ground Water Monitoring & Remediation》2002,22(1):46-61

Contamination from the use of chlorinated solvents, often classified as dense nonaqueous phase liquids (DNAPLs) when in an undissolved state, pose environmental threats to ground water resources worldwide. DNAPL site characterization method performance comparisons are presented in a companion paper (Kram et al. 2001). This study compares the costs for implementing various characterization approaches using synthetic unit model scenarios (UMSs), each with particular physical characteristics. Unit costs and assumptions related to labor, equipment, and consumables are applied to determine costs associated with each approach for various UMSs. In general, the direct-push sensor systems provide cost-effective characterization information in soils that are penetrable with relatively shallow (less than 10 to 15 m) water tables. For sites with impenetrable lithology using direct-push techniques, the Ribbon NAPL Sampler Flexible Liner Underground Technologies Everting (FLUTe) membrane appears to be the most cost-effective approach. For all scenarios studied, partitioning interwell tracer tests (PITTs) are the most expensive approach due to the extensive pre-and post-PITT requirements. However, the PITT is capable of providing useful additional information, such as approximate DNAPL saturation, which is not generally available from any of the other approaches included in this comparison.  相似文献   

A Reconnaissance Method for Delineation of Tracts for Regional-Scale Mineral-Resource Assessment Based on Geologic-Map Data     

Raines  Gary L.  Mihalasky  Mark J. 《Natural Resources Research》2002,11(4):241-248

The U.S. Geological Survey (USGS) is proposing to conduct a global mineral-resource assessment using geologic maps, significant deposits, and exploration history as minimal data requirements. Using a geologic map and locations of significant pluton-related deposits, the pluton-related-deposit tract maps from the USGS national mineral-resource assessment have been reproduced with GIS-based analysis and modeling techniques. Agreement, kappa, and Jaccard's C correlation statistics between the expert USGS and calculated tract maps of 87%, 40%, and 28%, respectively, have been achieved using a combination of weights-of-evidence and weighted logistic regression methods. Between the experts' and calculated maps, the ranking of states measured by total permissive area correlates at 84%. The disagreement between the experts and calculated results can be explained primarily by tracts defined by geophysical evidence not considered in the calculations, generalization of tracts by the experts, differences in map scales, and the experts' inclusion of large tracts that are arguably not permissive. This analysis shows that tracts for regional mineral-resource assessment approximating those delineated by USGS experts can be calculated using weights of evidence and weighted logistic regression, a geologic map, and the location of significant deposits. Weights of evidence and weighted logistic regression applied to a global geologic map could provide quickly a useful reconnaissance definition of tracts for mineral assessment that is tied to the data and is reproducible.  相似文献   

Participatory selection process for indicators of rangeland condition in the Kalahari   总被引：2，自引：0，他引：2  

Mark S Reed  & Andrew J Dougill 《The Geographical journal》2002,168(3):224-234

To develop indicator–based management tools that can facilitate sustainable natural resource management by non–specialists, meaningful participation of stakeholders is essential. A participatory framework is proposed for the identification, evaluation and selection of rangeland condition indicators. This framework is applied to the assessment of rangeland degradation processes and sustainable natural resource management with pastoralists in the southern Kalahari, Botswana. Farmer knowledge focused on vegetation and livestock, with soil, wild animal and socio–economic indicators playing a lesser role. Most were indicators of current rangeland condition; however 'early warning' indicators were also identified by some key informants. This demonstrates that some local knowledge is process–based. Such knowledge could be used to improve indicator–based management tools and extension advice on the livelihood adaptations necessary to prevent or reduce ecological change, capable of threatening livelihood sustainability. There is evidence that social background influences indicator use. Communal farmers rely most heavily on vegetation and livestock indicators, whilst syndicate and land–owning pastoralists cite wild animal and soil–based indicators most frequently. These factors must be considered if indicator–based management tools are to meet the requirements of a diverse community.  相似文献   

Deep-water renewal in a Scottish fjord: temperature, salinity and oxygen isotopes     

William E. N. Austin  Mark E. Inall 《Polar research》2002,21(2):251-257

The sea lochs (fjords) of north-west Scotland are located in a region of Europe particularly well situated to monitor changes in westerly air streams. The moisture transported in these air streams has a profound effect on regional precipitation, freshwater run-off and, in turn, sea loch circulation. The gentle slope of the regional salinity:δ¹⁸O mixing-line, defined as 0.18 ‰ per salinity unit, suggests that the temperature: δ¹⁸O relationship may be readily resolved in these coastal waters. Deep-water renewal events, both observed and predicted from empirical models, in the bottom-waters of Loch Etive provide an opportunity to assess the temperature, salinity and δ¹⁸O relationship. Predicted changes in δ¹⁸O_calcite as a function of changing salinity (ΔS) and changing temperature (ΔT) during deep-water renewal events suggest that >80% fall above analytical detection limits. The theoretical likelihood of recording such renewal events in the "palaeoclimate" record appears to be promising, but temperature and salinity change during renewal events may have either sign. Scottish fjords, because of the relatively small impact which salinity has on δ¹⁸O_water, may provide useful study sites in palaeoclimate research, particularly where palaeotemperature is the primary record of interest.  相似文献   

Active tectonics of the South Caspian Basin   总被引：15，自引：0，他引：15  

James Jackson  Keith Priestley  Mark Allen  Manuel Berberian 《Geophysical Journal International》2002,148(2):214-245

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Chasing a 'loose and baggy monster': almshouses and the geography of charity     

John R. Bryson  Mark McGuiness  & Robert G. Ford 《Area》2002,34(1):48-58

This paper goes some way towards redressing the lack of geographical literature on charity through exploring the geography of the British domestic charitable sector. The size and geography of the third sector is outlined, followed by an analysis of how almshouses can be understood as inherently geographical and deeply embedded in local social networks of inclusion as well as exclusion.  相似文献   

The geography of water conflict and cooperation: internal pressures and international manifestations   总被引：2，自引：0，他引：2  

Meredith Giordano  Mark Giordano  & Aaron Wolf 《The Geographical journal》2002,168(4):293-312

Studies on transboundary water conflict and cooperation generally consider interstate relations over shared water resources as distinct from intrastate relations. While connections have been made between international water relations and regional relationships in general, it is conceivable that international water conflict and cooperation may also be influenced by domestic water events and vice versa. This paper seeks to investigate the dynamics of water interactions across geographic scale and their relationship to broader international affairs. The research approach involves the creation of an analytical framework for assessing possible linkages between external and internal interactions over freshwater resources. The framework is applied to three case studies – the Middle East, South Asia and Southern Africa – utilizing 'event data'. To validate the findings from the quantitative analyses, the results are compared with conventional qualitative understandings of water and overall relations in the three regions. The comparison demonstrates not only the efficacy of the analytical framework in general, but also highlights, at least in terms of the specific case studies selected, the disparate water dynamics across geographic regions and the importance of considering water events, both national and international, within larger political and historical contexts.  相似文献   

Synfolding remagnetization and deformation: results from Palaeozoic sedimentary rocks in West Virginia     

Michael T. Lewchuk  Mark Evans  R. Douglas Elmore 《Geophysical Journal International》2003,152(2):266-279

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Rock-magnetic properties of multicomponent natural remanent magnetization in alluvial red beds (NE Spain)   总被引：1，自引：0，他引：1  

Pauline P. Kruiver  Cor G. Langereis  Mark J. Dekkers  Wout Krijgsman 《Geophysical Journal International》2003,153(2):317-332

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Joint inversion of local, regional and teleseismic data for crustal thickness in the Eurasia–Africa plate boundary region     

Federica Marone  Mark van der Meijde  Suzan van der Lee  Domenico Giardini 《Geophysical Journal International》2003,154(2):499-514

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