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51.
. Naphthalenesulfonates and their condensation products with formaldehyde are manufactured in the chemical industry for broad application as tanning agents, dispersing agents, and as superplasticizers for concrete. With the disposal of waste they have found their way into the aquatic environment. Five monomeric naphthalenesulfonates and a group of dimeric sulfonated naphthalene-formaldehyde condensates (SNFC) were identified in the leachate and in groundwater observation wells downstream in the plume of the Karlsruhe-West landfill, situated in the Upper Rhine Valley in southwest Germany. For the main monomer of technical SNFC products, 2-naphthalenesulfonate (2-NS), the concentration in the leachate was 170 µg l–1, which decreased to 9.5 µg l–1 at a distance of about 300 m from the boundary of the landfill. In the Merdingen tracer test field, the transport of these compounds was studied under more controlled conditions in two tracer experiments with (1) two model compounds, and (2) a technical SNFC product and uranine as a reference tracer. In these experiments, the monomeric naphthalenesulfonates and the SNFC with n=2 behave as conservative tracers. Thus, the findings of the landfill study were supported by these results. Higher molecular SNFC were strongly retarded, which is attributed to adsorption to soil particles. The results of the second tracer experiment suggest a degradation of 2-NS and 2,6-naphthalenedisulfonate (2,6-NDS) after adaptation of the microorganisms in the groundwater aquifer as a consequence of the first tracer experiment.  相似文献   
52.
Comparison of Seismic Dispersion and Attenuation Models   总被引:2,自引:0,他引:2  
The frequency-dependent attenuation of seismic waves causes decreased resolution of seismic images with depth, and the difference in transmission losses induces amplitude variations with offset. Transmission losses may occur due to friction or fluid movement, or may result from scattering in thin-layer. Whatever the physical mechanism, they can often be conveniently described using an empirical formulation wherein the elastic moduli and propagation velocity are complex functions of frequency.We have compiled and compared algebraically and numerically eight different models involving complex velocity: the Kolsky-Futterman model, the power-law model, Kjartansson's model, Müller's model, Azimi's second and third model, the Cole-Cole model, and the standard linear-solid model.For two different parameter sets, the attenuation and phase velocity are computed in the seismic frequency band, and the plane-wave propagation of a Ricker wavelet for the other models is compared with that for the Kolsky-Futterman model. The first parameter set consists of parameters for each of the models calculated from expressions given in the appendix. These expressions make the different models behave similarly to the KF model. The second parameter set consists of model parameters that are numerically adapted to the KF model.By selecting proper parameters, all models, except the standard linear-solid model, show behavior similar to that of the Kolsky-Futterman model. The SLS model behaves differently from the other models as the frequency goes to zero or infinity. Broadband measurement data is needed to select a specific model for a given seismic experiment.  相似文献   
53.
54.
Data from 25 local catalogues and 30special studies of earthquakes in central,northern and northwestern Europe have beenincorporated into a Databank. The dataprocessing includes discriminating eventtypes, eliminating fake events and dupletsand converting different magnitudes andintensities to Mw if this is not givenby the original source. The magnitudeconversion is a key task of the study andimplies establishment of regressionequations where no local relations exist.The Catalogue contains tectonic events fromthe Databank within the area44°N–72°N,25°W–32°E and the time period1300–1993. The lower magnitude level forthe Catalogue entries is setat Mw == 3.50. The area covered by thedifferent catalogues are associated withpolygons. Within each polygon only datafrom one or a small number of the localcatalogues, supplemented by data fromspecial studies, enter the Catalogue. Ifthere are two or more such catalogues orstudies providing a solution for an event,a priority algorithm selects one entry forthe Catalogue. Then Mw is calculatedfrom one of the magnitude types, or frommacroseismic data, given by the selectedentry according to another priority scheme.The origin time, location, Mw magnitude and reference are specified for eachentry of the Catalogue. So is theepicentral intensity, I0, if providedby the original source. Following thesecriteria, a total of about 5,000earthquakes constitute the Catalogue.Although originally derived for the purposeof seismic hazard calculation within GSHAP,the Catalogue provides a data base for manytypes of seismicity and seismic hazardstudies.  相似文献   
55.
 In this paper we use a combination of numerical modeling and data analysis to gain a better understanding of the major characteristics of the circulation in the East Frisian Wadden Sea. In particular, we concentrate on the asymmetry of the tidal wave and its modulation in the coastal area, which results in a complex pattern of responses to the sea-level forcing from the North Sea. The numerical simulations are based on the 3-D primitive equation General Estuarine Transport Model (GETM) with a horizontal resolution of 200 m and terrain-following vertical coordinates. The model is forced at its open boundaries with sea-level data from an operational model for the German Bight (German Hydrographic Office). The validation data for our model simulations include time series of tidal gauge data and surface currents measured at a pile in the back-barrier basin of the Island Langeoog, as well as several ADCP transects in the Accumer Ee tidal inlet. Circulation and turbulence characteristics are investigated for typical situations driven by spring and neap tides, and the analysis is focused on dominating temporal and spatial patterns. By investigating the response of five back-barrier basins with rather different morphologies to external forcing, an attempt is made to elucidate the dominating physical balances controlling the circulation in the individual sub-basins. It is demonstrated that the friction at the seabed tends to slow down the tidal signal in the shallow water. This leads to the establishment of flood dominance in the shallow sea north of the barrier islands. South of the islands, where the water volume of the channels at low tide is smaller than the tidal prism, the asymmetry of the tidal signal is shifted towards ebb dominance, a feature which is particularly pronounced at spring tide. At the northern open boundary, the tidal wave propagating from west to east generates a sea-level difference of ∼1 m along the boundary, and thereby triggers vigorous alongshore currents. The frictional control in the model is located in the inlets, as well as along the northern boundary. The correlation between velocity and turbulent kinetic energy tends to the establishment of a net southward transport, giving theoretical support to the observed accumulation of sediments on the intertidal flats. Weak turbulence along the northern shores of the barrier islands and the small magnitude of the residual currents there promote accumulation of suspended matter in these areas, although wave action will generally counteract this effect. Received: 29 May 2002 / Accepted: 26 September 2002 Responsible Editor: Jean-Marie Beckers Acknowledgements We are indebted to S. Dick for providing the data from the operational model of BSH and to B. Flemming for the useful discussions. The topography data and Fig. 1 have been prepared in cooperation with F. Meyer. Figure 2 has been prepared by G. Brink-Spalink. We also thank for the comments from an anonymous reviewer which helped to improve our paper.  相似文献   
56.
Summary ¶Various water budget elements (water supply to the atmosphere, ground water recharge, change in storage) are predicted by HTSVS for a period of 2050 days. The predicted water budget elements are evaluated by routine lysimeter data. The results show that land surface models need parameterizations for soil frost, snow effects and water uptake to catch the broad cycle of soil water budget elements. In principle, HTSVS is able to simulate the general characteristics of the seasonal changes in these water budget elements and their long-term accumulated sums. Compared to lysimeter data, there is a discrepancy in the predicted water supply to the atmosphere for summer and winter which may be attributed to the hardly observed plant physiological parameters like root depth, LAI, shielding factor, etc., the lack of measured downward long-wave radiation, and some simplifications made in the parameterizations of soil frost and snow effects. The fact that high resolution data for the evaluation of model results are missing and evaluation is made on the basis of the data from routine stations of a network is typical for the results of long-term studies on climate. Taking into account the coarse resolution of climate models, the coarse vertical resolution that is used in their LSMs, and the lack of suitable parameters needed, it seems that discrepancies in the order of magnitude found in this study are a general uncertainty in the results of land surface modeling on typical spatial and temporal scales of the climate system.Received October 8, 2001; revised February 15, 2002; accepted September 20, 2002 Published online: April 10, 2003  相似文献   
57.
The development of the boundary layer during a cold air outbreak in the FramStrait is documented by aircraft measurements. The convection was organisedinto roll vortices with aspect ratios increasing from 2.9 near the ice edgeto more than 6 at 100 km further downstream. This increase coincides with anincrease of the latent heat release in the cloud layer. The stability parameter-zi/L varies from about zero at the ice edge to 30 at a distance of 200 kmdownstream over open water where the satellite picture still shows cloudstreets. The increase is mainly due to the deepening of the boundary layer.The turbulent vertical sensible and latent heat fluxes near the surface amountto 400 W m-2 within a 300 km off-ice zone. 25% of the upward heat fluxin the subcloud layer is carried out by organised roll motions. Experimentswith a 2-dimensional non-hydrostatic model show a similar roll aspect ratio inthe first 50 km, but further downstream where condensational heating is moreimportant the modelled roll wavelengths are distinctly smaller than the observedones.  相似文献   
58.
59.
The mineralization of the active hydrothermal JADE field resembles in many aspects the Kuroko-type mineralization. The JADE field is located in a back-arc graben and is associated with a bimodal volcanism. Lead isotope data from igneous rocks, sediments, and ores further emphasize the similarities with the Kuroko ores and suggest that both sediments and volcanic rocks contributed comparable amounts of lead to the deposit. When compared to the sediments, a much larger volume of volcanic rocks must have contributed lead to the deposit, because of the considerably lower lead concentration of volcanic rocks. In contrast to the crustal type lead of the JADE field and the Kuroko-type sulfide deposits the lead isotope signatures of VMS-type deposits at mid-ocean ridges is distinctly different. In the absence of a sedimentary cover it reflects the composition of the mantle source, whereas in the presence of a sedimentary cover it is either a mixture of mantle and sedimentary lead or it may even be completely dominated by the latter. Received: 5 October 1995 / Accepted: 10 May 1996  相似文献   
60.
Summary Amphibolites are widespread in the eastern part of the Bohemian Massif, east of the South Bohemian Pluton. Based on their geological situation, their metamorphic evolution and their geochemistry, they were separated into three genetically different units: the Rehberg ophiolite, the Buschandlwand amphibolite and the Raabs group. The metamorphic Rehberg ophiolite consists of a ultramafic to mafic plutonic sequence overlain by a gabbro/dike complex and a volcanic section with basaltic, andesitic and rhyolitic volcanics associated with pelitic to psammitic sediments. The entire ophiolite underwent amphibolite facies metamorphism. Rock/MORB normalisation plots and other element ratio plots, such as Ti vs. V or Ta/Yb vs. Th/Yb argue for a supra-subduction zone environment as site of the origin of the Rehberg ophiolite. The Letovice ophiolite in Moravia is structured in a similar way. Geochemically it shows a more MORB like composition but also a distinct tholeiitic island arc group. Although there is no age data for the protolith of both ophiolites, it is believed that they have formed in an oceanic basin separating the Brunovistulian-Moravian block to the east and the Moldanubian block to the west. Possible traces of the continuation of the ophiolites towards the north can be found in the Stare Mesto ophiolites and the ophiolites surrounding the Sowie Gory block in the Sudetes.
Ophiolitrelikte am ostrand der Böhmischen Masse und ihre bedeutung für die tektonische entwicklung
Zusammenfassung Amphibolite sind in der Böhmischen Masse, östlich des Südböhmischen Plutons weit verbreitet. Ausgehend von ihrer geologischen Position, ihrer metamorphen Entwick lung und ihrer Geochemie lassen sie sich in drei genetisch unterschiedliche Einheiten teilen: den Rehberg Ophiolith, den Buschandlwand Amphibolit und die Raabser Gruppe. Der metamorphe Rehberg Ophiolith besteht aus einer ultramatischen bis mafischen plutonischen Abfolge, die von einem Gabbro/Gangkomplex überlagert wird und einer vulkanischen Folge mit Basalten, Andesiten and Rhyoliten, die mit tonigen und sandigen Sedimenten verknüpft sind. Der gesamte Ophiolithkörper wurde unter amphibolitfaziellen Bedingungen metamorph überprägt. Rock/MORB Diagramme und andere Elementdarstellungen, wie z.B. das Ti vs. V, oder das Ta/Yb vs. Th/Yb Diagramm sprechen für eine Entstehung des Rehberg Ophioliths in einer Suprasubduction Zone. Der Letovice Ophiolith in Mähren weist eine ähnliche Struktur auf. Geochemisch zeigt er stärkere Ähnlichkeiten mit MORB, enthält aber auch Elemente von tholeiitischen Inselbogenbasalten. Auch wenn es für beide Ophiolithe noch keine Protolith-Altersdaten gibt, scheint es dennoch wahrscheinlich, daß sie in einem Ozeanbecken, das den Brunovistulisch-Moravischen Kontinentalblock im Osten vom Moldanubischen Kontinent im Westen trennt, gebildet wurden. Die mögliche Fortsetzung beider Ophiolithe könnten im Norden der Stare Mesto Ophiolith und die Ophiolithe rund um den Sowie Gory Block in den Sudeten darstellen.


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