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Igor Jemcov 《Environmental Geology》2007,51(5):767-773
The management of groundwater flow systems in karst regions appears, at present, to be the most important procedure for solving
water deficiency problems during periods of low rainfall. Faced with a lack of data for characterizing the water supply potential
of karst aquifers, analyses of spring hydrographs may provide valuable indirect information regarding the structure of karst
hydrogeological systems. To estimate the optimal exploitation capacities of karstic sources, a stochastic-conceptual approach
was applied in case studies from the Serbian karst. Water supply potentials were initially evaluated on the basis of groundwater
budgets. Further steps towards defining optimal “exploitable” regimes included analyses of storage changes in karst water
reservoirs under natural conditions and calculation of the potential expansion of currently tapped sources. The results obtained
through these analyses are a significant contribution to feasibility studies and aid in the avoidance of problems of overexploitation. 相似文献
23.
Igor E. Agranovski 《洁净——土壤、空气、水》2007,35(1):111-117
A new personal bioaerosol sampler has been developed and verified as an efficient tool for monitoring of viable/non‐viable airborne microorganisms, including bacteria, fungi, and viruses. The operational principle of the device is based on continuous passage of an air sample through porous media submerged into a liquid layer. During motion along narrow and tortuous ways inside the porous media, the air stream is split into a large number of ultra small bubbles with the particulates are being scavenged by these bubbles and, thus, effectively trapped. The device was initially verified for monitoring of viable airborne bacteria and fungi, firstly, under controlled laboratory conditions and later in a field. It was demonstrated that bacterial recovery rates for these two groups of microorganisms were very high and the device was found to be fully feasible for such monitoring. The next step of the device investigation was performed in the laboratory on monitoring viable airborne viruses with a range of sensitivities to physical and biological stresses. As the result, the new personal sampler demonstrated a very high recovery rate even for viruses which are rather sensitive to environmental stress (Avian Influenza, SARS, Mumps, etc.). Some following field studies, undertook in a hospital and animal houses, also demonstrated an excellent performance of the new device for selective and reliable monitoring of viable airborne viruses even in environments highly contaminated by other microorganisms. This paper reviews the main development staged of the new personal bioaerosol sampler. 相似文献
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Neil S. Mancktelow Daniel F. Stöckli Balz Grollimund Wolfgang Müller Bernhard Fügenschuh Giulio Viola Diane Seward Igor M. Villa 《International Journal of Earth Sciences》2001,90(3):593-622
Alpine deformation of Austroalpine units south of the Tauern window is dominated by two kinematic regimes. Prior to intrusion of the main Periadriatic plutons at ~30 Ma, the shear sense was sinistral in the current orientation, with a minor north-side-up component. Sinistral shearing locally overprints contact metamorphic porphyroblasts and early Periadriatic dykes. Direct Rb-Sr dating of microsampled synkinematic muscovite gave ages in the range 33-30 Ma, whereas pseudotachylyte locally crosscutting the mylonitic foliation gave an interpreted 40Ar-39Ar age of ~46 Ma. The transition from sinistral to dextral (transpressive) kinematics related to the Periadriatic fault occurred rapidly, between solidification of the earlier dykes and of the main plutons. Subsequent brittle-ductile to brittle faults are compatible with N-S to NNW-SSE shortening and orogen-parallel extension. Antithetic Riedel shears are distinguished from the previous sinistral fabric by their fine-grained quartz microstructures, with local pseudotachylyte formation. One such pseudotachylyte from Speikboden gave a 40Ar-39Ar age of 20 Ma, consistent with pseudotachylyte ages related to the Periadriatic fault. The magnitude of dextral offset on the Periadriatic fault cannot be directly estimated. However, the jump in zircon and apatite fission-track ages establishes that the relative vertical displacement was ~4-5 km since 24 Ma, and that movement continued until at least 13 Ma. 相似文献
25.
Radiogenic isotopes in fluid inclusions 总被引:7,自引:0,他引:7
Radiogenic isotopes studied in fluid inclusions are still a limited field, with great potential for expansion as analytical techniques improve. The main limitation for Sr, Ar and He isotope work is the very small number of radiogenic atoms produced in a typical fluid inclusion. The requirements to analysts are correspondingly high. Examples show that isotopic tracing on fluid inclusion fluids can be a decisive tool in solving geological problems. 相似文献
26.
Abstract The geological structure of the Koreyskaya River area exhibits a complex combination of turbidite—olistostrome deposits making up a matrix and synsedimentary tectonic enclosures represented by allochthons of formations different in age and genesis. Three tectono-stratigraphic units can be distinguished, that have been combined into a single section by accretion. New data on radiolarians have been used to date the tectonic enclosures and matrix. Abundant Mesozoic radiolarians (from Triassic to Late Jurassic) and also Late Permian radiolarians were found in cherty and siliceous mudstone olistoliths and cherty allochthons. 相似文献
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Igor V. Igumenshchev Marek A. Abramowicz & Igor D. Novikov 《Monthly notices of the Royal Astronomical Society》1998,298(4):1069-1078
We numerically construct slim, global, vertically integrated models of optically thin, transonic accretion discs around black holes, assuming a regularity condition at the sonic radius and boundary conditions at the outer radius of the disc and near the black hole. In agreement with several previous studies, we find two branches of shock-free solutions, in which the cooling is dominated either by advection or by local radiation. We also confirm that the part of the accretion flow where advection dominates is in some circumstances limited in size: it does not extend beyond a certain outer limiting radius. New results found in our paper concern the location of the limiting radius and the properties of the flow near to it. In particular, we find that beyond the limiting radius the advective-dominated solutions match on to Shapiro, Lightman &38; Eardley (SLE) discs through a smooth transition region. Therefore, the full global solutions are shock-free and unlimited in size. There is no need to postulate an extra physical effect (e.g. evaporation) for triggering the ADAF–SLE transition. It occurs as a result of standard accretion processes described by the classic slim disc equations. 相似文献