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121.
Vladimir Frid Gady Liskevich Dmitriy Doudkinski Nikolay Korostishevsky 《Environmental Geology》2008,53(7):1503-1508
This paper deals with an employment of electrical resistivity imaging (ERI) for survey of leachate content on the waste disposal
site in Northern Israel. The research consisted of conducting ten ERI lines and drilling investigation wells. Data simulation
used a 2D EarthImager inversion program. Analysis of 2D ERI interpretation results shows that determination of the boundary
between the landfill body bottom intensively saturated with leachates and underlying layers of highly water saturated fat
nonconsolidated clays presents a challenge. However, statistical analysis of ERI data indicates that standard deviation and
confidence interval of a set of resistivity data measured in the landfill body are significantly larger than those in underlying
clays. Moreover, maximum changes of these parameters are found on the boundary between landfill body and underlying soil,
thus reflecting natural differences in scattering of resistivity data measured in these two objects. 相似文献
122.
Kevin G. Taylor Karen A. Hudson-Edwards Andrew J. Bennett Vladimir Vishnyakov 《Applied Geochemistry》2008
The sediments in the Salford Quays, a heavily-modified urban water body, contain high levels of organic matter, Fe, Zn and nutrients as a result of past contaminant inputs. Vivianite [Fe3(PO4)2 · 8H2O] has been observed to have precipitated within these sediments during early diagenesis as a result of the release of Fe and P to porewaters. These mineral grains are small (<100 μm) and micron-scale analysis techniques (SEM, electron microprobe, μ-EXAFS, μ-XANES and Raman) have been applied in this study to obtain information upon the structure of this vivianite and the nature of Zn uptake in the mineral. Petrographic observations, and elemental, X-ray diffraction and Raman spectroscopic analysis confirms the presence of vivianite. EXAFS model fitting of the FeK-edge spectra for individual vivianite grains produces Fe–O and Fe–P co-ordination numbers and bond lengths consistent with previous structural studies of vivianite (4O atoms at 1.99–2.05 Å; 2P atoms at 3.17–3.25 Å). One analysed grain displays evidence of a significant Fe3+ component, which is interpreted to have resulted from oxidation during sample handling and/or analysis. EXAFS modelling of the Zn K-edge data, together with linear combination XANES fitting of model compounds, indicates that Zn may be incorporated into the crystal structure of vivianite (4O atoms at 1.97 Å; 2P atoms at 3.17 Å). Low levels of Zn sulphate or Zn-sorbed goethite are also indicated from linear combination XANES fitting and to a limited extent, the EXAFS fitting, the origin of which may either be an oxidation artifact or the inclusion of Zn sulphate into the vivianite grains during precipitation. This study confirms that early diagenetic vivianite may act as a sink for Zn, and potentially other contaminants (e.g. As) during its formation and, therefore, forms an important component of metal cycling in contaminated sediments and waters. Furthermore, for the case of Zn, the EXAFS fits for Zn phosphate suggest this uptake is structural and not via surface adsorption. 相似文献
123.
124.
Non-linear elastic behaviour of damaged rocks 总被引:1,自引:0,他引:1
Vladimir Lyakhovsky Ze'ev Reches Ram Weinberger Thurman E. Scott 《Geophysical Journal International》1997,130(1):157-166
The pervasive damage of rocks by microcracks and voids strongly affects their macroscopic elastic properties. To evaluate the damage effects, we derive here the macroscopic stress-strain relations for a 3-D elastic solid with non-interacting cracks embedded inside a homogeneous matrix. The cracks considered are oriented either perpendicular to the maximum tension axis, or perpendicular to the maximum compression axis. In the first case they dilate during loading and in the second case they contract during loading. We derive a solution for the elastic energy of this rock following the self-consistent scheme of Budiansky & O'Connell (1976). The solution describes the stress-strain relations in terms of Λd and μd , which are the modified Lame constants, and an additional parameter Λ. The latter accounts for the non-linear behaviour of the solid and is related to crack density. The solution predicts a non-linear elastic rheology even for an infinitesimal strain of ɛ < 0.001, and abrupt change in the elastic moduli when the loading reverses from uniaxial compression to uniaxial tension.
We use the derived solution to analyse rock-mechanics experiments in which beams of Indiana limestone were deformed under four-point loading. This configuration provides simultaneously the apparent tensile and compressive moduli for small strains. The apparent moduli fit the effective elastic moduli calculated with the present damage model well, including the differences between tensile and compressive moduli. 相似文献
We use the derived solution to analyse rock-mechanics experiments in which beams of Indiana limestone were deformed under four-point loading. This configuration provides simultaneously the apparent tensile and compressive moduli for small strains. The apparent moduli fit the effective elastic moduli calculated with the present damage model well, including the differences between tensile and compressive moduli. 相似文献
125.
126.
Vladimir Strelnitski 《Astrophysics and Space Science》1997,252(1-2):279-287
This paper discusses recent results obtained by myself and my colleagues in three domains of astrophysics: interstellar supersonic turbulence, circumstellar disks, and natural masers and lasers. S.A. Kaplan, S.B. Pikelner, and I.S. Shklovskii were among those who, 30-40 years ago, laid the foundation of these domains.H2O masers become an effective probe of supersonic turbulence associated with mass outflow from very young stars. They demonstrate a very low (1) fractal dimension of the spatial set on which turbulence dissipates its kinetic energy, and, thereby, a strong intermittency of the turbulence. They also indicate that supersonic turbulence, like incompressible turbulence, has an inner scale, on which the bulk of turbulent energy dissipates in low-Mach, random shocks. H2O masers themselves find thereby a new pumping source in these random shocks.Masers in hydrogen recombination lines, discovered 8 years ago, originate in a circumstellar disk surrounding a massive star MWC 349A. They give a possibility to investigate kinematics and structure of the disk. Far-infrared nydrogen recombination lines, recently detected in MWC349A from the Kuiper Airborn Observatory, proved to be amplified as well. They are the first known natural amplifiers of electromagnetic waves in the laser wavelength domain. Analysis of their radiation, along with the radiation in other recombination lines, gives a possible key to understanding the lack of optical lasers in the Universe. 相似文献
127.
As a key factor limiting primary productivity in marine ecosystem, dissolved iron(DFe) export from fluvial systems has increased recently. There is particular concern about discharges of DFe during extreme flooding, when they are thought to increase considerably. An extreme flood event that caused inundation of extensive areas of Far Eastern Russia and Northeastern China occurred in the basin of the Amur River during summer and autumn 2013. During this event, water samples were collected in the middle reaches of the Amur River and the lower reaches at Khabarovsk City and analyzed for DFe concentrations and other aquatic parameters. The results show that the average DFe concentrations in the middle reaches of the Amur River(right bank) and at Khabarovsk were 1.11 mg/L and 0.32 mg/L, respectively, during the extreme flood in 2013. The total discharge of DFe during the flood event was 6.25 × 104 t. The high discharge of DFe during the flood reflects the elevated discharge of the river, hydrologically connected riparian wetlands, vast quantities of terrestrial runoff, and flood discharges from the Zeya and Bureya reservoirs. These results show that long-term monitoring is needed to identify and assess the impacts of DFe transport on the downstream reaches, estuarine area, and coastal ecosystems of the Amur River. 相似文献
128.
Vladimir A. Lisitsin 《Natural Resources Research》2016,25(3):269-282
The Bendigo and Stawell zones in Victoria and the Mossman Orogen in north Queensland host numerous orogenic gold deposits and are likely to contain significant undiscovered gold resources. This paper discusses applications of Zipf’s law to estimate the scale of residual gold endowment in each of the regions. Testing various plausible scenarios on whether or not the largest deposit in each region has been discovered and its endowment adequately evaluated provided some measure of uncertainty of assessment results. The Bendigo and Stawell zones are estimated to host 12 undiscovered ore fields with >31 t (1 Moz) of contained gold and another 35 undiscovered ore fields with >10 t (0.32 Moz) of gold, containing in total 1600 t (51 Moz) of gold. The total residual orogenic gold endowment of the Mossman Orogen is estimated to be between 3 and 30 t of gold, contained in extensions of known deposits and up to six significant undiscovered gold ore fields each containing >1 t of gold. These estimates are comparable to results of recent three-part quantitative mineral resource assessments for those areas. 相似文献
129.
Stuart E. Hamilton Alexander Angelov Vladimir Atanasov Marco Millones 《The Professional geographer》2016,68(1):115-128
This article introduces a quantitative methodology for analyzing contested map borders. The article applies the new analytical technique to a data set of thirty maps showing Bulgaria in ca. 800 CE, a disputed state and period in medieval historiography with relevance to modern national politics and territorial claims. Based on the data set, we generate a series of new maps that make explicit the fluid medieval boundaries and general disagreement among geographers and historiographers. Our analysis begins with a simple point-in-polygon procedure to create a majority map that depicts the points included within the borders of the Bulgarian polity in sixteen or more of the maps (>50 percent). The majority map is then combined with percentage maps, confidence interval map boundaries, and cluster maps. The confidence interval maps are created via a spatial bootstrapping procedure and measure the uncertainty in the majority map. The cluster maps are developed via a radial basis function and provide insight into the potential affectivity based on the cartographers' countries of origin. The final map reflects the general modern consensus of the borders of the Bulgarian polity around 800 CE. Besides its quantitative contribution to medieval and modern cartographic, historiographical, and political debates, this article has developed a widely applicable methodology for synthesizing map borders and territories in cases of cartographic disagreement. 相似文献
130.
The detailed seismic refraction investigation of the oceanic crust south of Shatsky Rise in the Northwestern Pacific revealed
a low velocity zone (LVZ) with an average compressional wave velocity of 6.3 km/s within layer 3. This conclusion is based
on the shadow zone for refractions on the travel time curves in their first arrivals from the M discontinuity. The LVZ may
be composed of oceanic plagiogranites because serpentinization of peridotites would probably lead to an increase in crustal
block volume with a concomitent decrease in density and thereby thickening and upwelling at the place of now “overdeepened”
ocean would be expected. 相似文献