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41.
42.
There is an exceptionally rich aquatic fauna in the epikarst, the skin of karst. High species richness in the epikarst, coupled
with its special vulnerability as the first point of entry of nearly all toxic spills, makes its protection especially important.
The epikarst fauna may also be an useful tool in tracing the potential route of pollutants. Copepods in epikarst have extremely
local distributions, and their body size is such that they are largely at the mercy of directional flows. In a series of caves
in southwest Slovenia and West Virginia, a significant fraction of the copepod species occur in less than 100 m of linear
extent. This suggests a pattern of highly restricted lateral flow under normal conditions and the distribution of copepods
could potentially be used to trace water movement. Under high flow conditions as would often be the case with toxic spill,
mounding of water may increase the lateral radius of flow. Nevertheless, copepods may be useful tracers. 相似文献
43.
P. M. Nikolić S. Ðurić D. M. Todorović D. Vasiljević-Radović V. Blagojević P. Mihajlović J. Elazar K. T. Radulović A. I. Bojičić D. Urošević 《Physics and Chemistry of Minerals》2001,28(1):44-51
Electron transport properties of single crystal and polycrystalline natural mineral galena (PbS) samples from the Trep?a mine, Yugoslavia, were determined using the photoacoustic frequency transmission technique. Their thermal diffusivity (D T≈0.16 × 10?5 m2 s?1), the coefficient of diffusion (D between 0.15×10?2 0.16×10?2 m2 s?1) and lifetime of the excess carrier (τ≈35 μs and the front and rear recombination velocity (s g≈65.5 m s?1 and s b≈66.4 m s?1, respectively), were calculated by comparing the experimental results and the theoretical photoacoustic amplitude and phase signals. The lattice parameter obtained by X-ray work was a?=5.936?Å. The free carrier concentration of these single-crystal samples was measured using the Hall method (N?=?3×1018 cm?3). Measurements of the optical reflectivity of the same samples, as a function of wavelength, in the infrared and far infrared ranges, were performed. In the far infrared range a free electron plasma frequency was observed and numerically analyzed, using the least-squares fitting procedure. The values of optical parameters were calculated and the value of the free carrier concentration obtained by the Hall method was confirmed. 相似文献
44.
Tanja Waterwiese Niranjan D. Chatterjee Ivana Dierdorf Jörg Göttlicher Herbert Kroll 《Contributions to Mineralogy and Petrology》1995,121(1):61-73
Internally consistent thermodynamic datasets available at present call for a further improvement of the data for nepheline
(Holland and Powell 1988; Berman 1991). Because nepheline is a common rock-forming mineral, an attempt has been made to improve
on the present state of knowledge of its thermodynamic properties. To achieve that goal, two heterogeneous reactions involving
nepheline, albite, jadeite and a-quartz in the system NaAlSiO4-SiO2 have been reversed bylong duration runs in the range 460 ≤ T(°C) ≤ 960 and 10 ≤ P(kbar) ≤ 22. Given sufficiently long run times, thealbite run products approach internal equilibrium with respect to their Al,Si order-disorder states. Using appropriate thermochemical, thermophysical, and volumetric data,
Landau expansion for albite, and the relevant reaction reversals, a refined thermodynamic dataset (ΔfHi0 and Si0) has been derived for nepheline, jadeite, a-quartz, albite, and monalbite. Our refined data agree very well with theircalorimetric counterparts, but have smaller uncertainties. The refined dataset for ΔfHi0 and Si0, including their uncertainties and correlation, help generate the NaAlSiO4-SiO2 phase diagram including 2a confidence interval for eachP-T curve (Fig. 5).
Editorial responsibility: W. Schreyer 相似文献
45.
Djuro Radinović 《Pure and Applied Geophysics》1972,93(1):159-176
Summary A numerical model for the quantitative precipitation forecasting has been formulated. In this model precipitation is computed as a function of the vertical velocity and humidity distribution in the atmosphere. The orographic influence on the vertical velocity was taken into consideration. Further, the relation between vertical velocity and static stability of the atmosphere has been considered and, as an important factor in the condensation process, was introduced into the equation of the model. This numerical model for the precipitation forecasting has been applied in the North Adriactic Sea region, which is characterized by a strong vertical gradient of the specific humidity and pronounced orographic influence. The results achieved show that this model could successfully be used as an objective method in the routine forecasting of the amount of precipitation. 相似文献
46.
Lj. Barić 《Mineralogy and Petrology》1969,13(3-4):233-249
Zusammenfassung In der Umgebung der Stadt Prilep in Mazedonien kommen an mehreren Stellen in einer hochmetamorphen, aus Glimmerschiefern und Amphiboliten bestehenden Zone Calcit- und Dolomitmarmore vor. In den letzterwähnten wurden bisher Dolomit, Calcit, Korund, Diaspor, -Zoisit, Rutil, Fluorit, Achroit, Pyrit, Muskovit, Illit, Margarit und Chlorit (vonErdmannnsdörfer auch Kossmatit) festgestellt. Diese Paragenese ist regionalmetamorph entstanden.
Mit 1 Abbildung 相似文献
Dolomite-marble in the surroundings of the town prilep, macedonia, and its minerals
Summary Calcite- and dolomite-marbles occur in a highly metamorphic series together with micaschists and amphibolites at several localities in the surroundings of Prilep, Macedonia. In the dolomite-marbles, dolomite, calcite, corundum, diaspore, -zoisite, rutile, fluorite, achroite pyrite, muscovite, illite, margarite, chlorite, and kossmatite (the last only byErdmannsdörffer) have been found. The paragenesis is of regional metamorphic origin.
Mit 1 Abbildung 相似文献
47.
Milan Stojković Jasna Plavšić Stevan Prohaska Dragutin Pavlović Jovan Despotović 《水文科学杂志》2020,65(3):387-400
ABSTRACTClimate change projections of precipitation and temperature suggest that Serbia could be one of the most affected regions in southeastern Europe. To prepare adaptation measures, the impact of climate changes on water resources needs to be assessed. Pilot research is carried out for the Lim River basin, in southeastern Europe, to predict monthly flows under different climate scenarios. For estimation of future water availability, an alternative approach of developing a deterministic-stochastic time series model is chosen. The proposed two-stage time series model consists of several components: trend, long-term periodicity, seasonality and the stochastic component. The latter is based on a transfer function model with two input variables, precipitation and temperature, as climatic drivers. The Nash-Sutcliffe model efficiency for the observed period 1950–2012 is 0.829. The model is applied for the long-term hydrological prediction under the representative concentration pathway (RCP) emissions scenarios for the future time frame 2013–2070. 相似文献
48.
The aim of this paper is to present an application of robust inverse Nyquist array control design method to a milling circuit in Majdanpek Copper Mine. An existent model of a milling circuit was adopted to respond to robust inverse Nyquist array methodology demand by introducing model uncertainty, and optimal robust controller of milling circuit is designed. The proposed controller is robust for reference signals. The robustness of multivariable feedback systems with designed controller is tested and compared with different, previously designed multivariable controllers. Simulation results, in time domain, demonstrate the preferable performance of the designed robust controller in setpoint tracking. Implementation of the new controller without any investments in new equipment significantly improves performance of the milling process. 相似文献
49.
Nico-Alexander Urbanski Malte Vöge Ralf Seyfried Lars Rüpke Tanja Petersen Till Hanebuth Matthias Hort 《International Journal of Earth Sciences》2002,91(4):712-722
The intention of our study was to gain new insight into the complex interplay between different types of eruption of the Stromboli volcano by combining detailed field observation with different geophysical methods. We recorded more than 600 eruptions by use of continuous Doppler radar measurements. We detected the onset of the seismic precursor and the beginning of the visible eruption by use of seismic and infrared data. Two soil samples per day were used to monitor the effect of humidity on the eruptive style. We mapped the crater region as a reference base for the long-term morphological changes of the active region and for the exact positions of our measurement systems. Two distinct types of eruption were distinguished from each other on the basis of seismic and radar data - short, wide-angle Strombolian explosions and pulsating, sharp angle fountain-like eruptions. Data and visual observations imply that weather conditions significantly effect volcanic activity. We also interpret the intensification of eruptive activity during our field study as replenishment of the reservoir with a new batch of magma in late September 2000. 相似文献
50.
The formation and evolution of a large amplitude MHD perturbation propagating perpendicular to the magnetic field in a perfectly conducting low plasma is studied. The perturbation is generated by an abrupt expansion of the source region. Explicit expressions for the time and the distance needed for the transformation of the perturbation's leading edge into a shock wave are derived. The results are applied to coronal conditions and the dynamic spectra of the radio emission excited by the shock are synthesized, reproducing metric and kilometric type II bursts. The features corresponding to the metric type II burst precursor and the moving type IV burst in the case of kilometric type II bursts are identified. A specific radio signature that is sometimes observed at the onset of a metric type II burst is found to appear immediately before the shock wave formation due to the associated growth of the magnetic field gradient. Time delays and starting frequencies of bursts' onsets are calculated and presented as a function of the impulsiveness of the source-region expansion, using different values of the ambient Alfvén velocity and various time profiles of the expansion velocity. The results are confronted with the observations of metric and kilometric type II solar radio bursts. 相似文献