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   

Habitat, occurrence and conservation of Saharo-Arabian-Turanian element Forsskaolea tenacissima L. in the Iberian Peninsula   总被引：1，自引：0，他引：1  

Javier Cabello  Domingo Alcaraz  Francisco Gmez-Mercado  Juan F. Mota  Javier Navarro  Julio Peas  Esther Gimnez 《Journal of Arid Environments》2003,53(4):491-500

The aim of this study is to assess the Iberian populations of Forsskaolea tenacissima L. according to its biogeographical interest, habitat, geographical range and conservation status. Results point out that they are restricted to gravel wadis of Tabernas Desert (SE Spain), are scarcely included in protected areas and represent historically isolated populations with relict behaviour. We also describe a new association, Senecioni-Forsskaoleetum tenacissimae. Conservation status of species is cause for concern and two conservation actions must be carried out. Firstly, protected areas should house Forsskaolea populations and secondly, phytosociological characterization of a community allows inventorying its habitat and directing conservation efforts to community level.  相似文献   

Atmospheric sensitivity to roughness length in a regional atmospheric model over the Ohio–Tennessee River Valley     

Arturo I. Quintanar  Rezaul Mahmood  Astrid Suarez  Ronnie Leeper 《Meteorology and Atmospheric Physics》2016,128(3):315-330

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Historical floods in Tabasco and Chiapas during sixteenth–twentieth centuries     

Arturo Valdés-Manzanilla 《Natural Hazards》2016,80(3):1563-1577

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An integrated GIS-based tool for aquifer test analysis     

R. Criollo  V. Velasco  E. Vázquez-Suñé  A. Serrano-Juan  M. Alcaraz  A. García-Gil 《Environmental Earth Sciences》2016,75(5):391

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Effect of climatic oscillations on flood occurrence on Papaloapan River,México,during the 1550–2000 period     

Arturo Valdés-Manzanilla 《Natural Hazards》2018,94(1):167-180

This study presents a chronology of historical and measured flood events in the Papaloapan River basin of Mexico during 450 years. Twenty-eight historical floods were recorded during the period 1550–1948 on this river and one flood event (1969) in the instrumental era (1949–2000), of which 14 were extraordinary floods and only 15 were catastrophic ones. There were several flood-rich decades during 1860–1870, 1880–1890, 1920–1930 and 1940–1950. Wavelet analysis found a significant flooding periodicity of 58 years. The wavelet coherence analysis found that flooding had an in-phase relationship with the Atlantic Multidecadal Oscillation and also with the Pacific Decadal Oscillation. Logistic regression corroborated that there exists a positive relationship between floods events and these two natural climatic oscillations. The logistic regression model predicted correctly 92% of flood events.  相似文献   

Diagnosis of trace metal contamination in sediments: the example of Ensenada and El Sauzal, two harbors in Baja California, Mexico   总被引：1，自引：0，他引：1  

Huerta-Diaz MA  Delgadillo-Hinojosa F  Hernández-Ayón M  Segovia-Zavala JA  García-Esquivel Z  López-Zárate H  Siqueiros-Valencia A  Galindo-Bect S 《Marine environmental research》2008,66(3):345-358

Total metal concentrations in sediments from within Ensenada and El Sauzal Harbors are generally higher than at the mouths. Grain-size analyses suggested that this enrichment could be due to the presence of fine-grained sediments in the inner part of the harbors rather than to anthropogenic perturbations. The (Me/Al)(sample) ratios for Pb, Co, Ni and Fe were significantly higher for Ensenada Harbor relative to El Sauzal Harbor, whereas the ratios for Cd, Mn, Zn and Cu were statistically equivalent for both harbors. Calculated enrichment factors [EF(Me)=(Me/Al)(sample)/(Me/Al)(shale)] indicated that the metals showing slight enrichment were those associated with anthropogenic contamination (Pb, Zn), or probably related to primary productivity in the water column (Cd, Co). The levels of most of the metals were not greatly enriched, a consideration that is of the utmost importance when contamination issues are at stake.  相似文献   

Use of LIF for Real-Time In-Situ Mixed NAPL Source Zone Detection     

Mark L. Kram  Stephen H. Lieberman  Jerry Fee  Arturo A. Keller 《Ground Water Monitoring & Remediation》2001,21(1):67-76

The site characterization and analysis cone penetrometer system (SCAPS), equipped with realtime fluorophore detection capabilities, was used to delineate subsurface contaminant releases in an area where plating shop waste was temporarily stored. Records indicated that various nonaqueous phase liquids (NAPLs) were released at the site. The investigators advanced the SCAPS laser-induced fluorescence (LIF) sensor to depths beneath the water table of the principal water-bearing zone. The water table was located approximately 6 feet (1.8 m) below ground surface (bgs) across the site. Fluorescence, attributed to fuel compounds commingled with chlorinated solvents, was observed at depths ranging from 4.0 to 11.5 feet (1.2 to 3.5 m) bgs. Fluorescence, attributed to naturally occurring organic materials (by process of elimination and spectral characteristics) commingled with chlorinated solvent constituents, was observed at depths ranging from approximately 13 to 40 feet (4.0 to 12.2 m) bgs. Fluorescence responses from compounds confirmed to be commingled with chlorinated solvents indicates that the SCAPS fluorophore detection system is capable of indirectly delineating vadose zone and subaqueous chlorinated solvents and other dense nonaqueous phase liquids (DNAPLs) at contaminant release sites. This confirmation effort represents the first documented account of the successful application of LIF to identify a mixed DNAPL/LNAPL source zone.  相似文献   

Effect of neutrino magnetic moment on solar neutrino observations     

Arturo Cisneros 《Astrophysics and Space Science》1971,10(1):87-92

Neutrino spin precession effects in the magnetic field of the Sun are considered as an explanation of the outcome of Davis' solar neutrino experiments. Theoretically, it is possible to account for a neutrino magnetic moment only as the result of the interaction of the electromagnetic field with charged particles into which the neutrino can transform virtually. The currently accepted theory of weak interactions (the two component neutrino andV-A interactions) forbids a resulting magnetic moment interaction with the electromagnetic field for all such virtual processes. Modifications of this theory are considered to find out whether an appreciable precession effect is permitted within the experimentally established limits. It is found that the value for the neutrino magnetic moment evaluated under these theoretically anomalous circumstances is still so small that only the largest possible estimate for the magnetic field strength in the Sun's interior would cause the required effect.The author has received scholarship support from the Latin American Scholarship Program of American Universities during the preparation of this work.  相似文献   

Geochemical Evidence for Slab Melting in the Trans-Mexican Volcanic Belt   总被引：3，自引：0，他引：3  

Gomez-Tuena  Arturo; Langmuir  Charles H.; Goldstein  Steven L.; Straub  Susanne M.; Ortega-Gutierrez  Fernando 《Journal of Petrology》2007,48(3):537-562

Geochemical studies of Plio-Quaternary volcanic rocks from theValle de Bravo–Zitácuaro volcanic field (VBZ) incentral Mexico indicate that slab melting plays a key role inthe petrogenesis of the Trans-Mexican Volcanic Belt. Rocks fromthe VBZ are typical arc-related high-Mg andesites, but two differentrock suites with distinct trace element patterns and isotopiccompositions erupted concurrently in the area, with a traceelement character that is also distinct from that of other Mexicanvolcanoes. The geochemical differences between the VBZ suitescannot be explained by simple crystal fractionation and/or crustalassimilation of a common primitive magma, but can be reconciledby the participation of different proportions of melts derivedfrom the subducted basalt and sediments interacting with themantle wedge. Sr/Y and Sr/Pb ratios of the VBZ rocks correlateinversely with Pb and Sr isotopic compositions, indicating thatthe Sr and Pb budgets are strongly controlled by melt additionsfrom the subducted slab. In contrast, an inverse correlationbetween Pb(Th)/Nd and ¹⁴³Nd/¹⁴⁴Nd ratios, which extend to lowerisotopic values than those for Pacific mid-ocean ridge basalts,indicates the participation of an enriched mantle wedge thatis similar to the source of Mexican intraplate basalts. In addition,a systematic decrease in middle and heavy rare earth concentrationsand Nb/Ta ratios with increasing SiO₂ contents in the VBZ rocksis best explained if these elements are mobilized to some extentin the subduction flux, and suggests that slab partial fusionoccurred under garnet amphibolite-facies conditions. KEY WORDS: arcs; mantle; Mexico; sediment melting; slab melting  相似文献