The field distortion of air electric potential gradient radiosondes and the determination of form factors     

Horst Riekert  Richard Mühleisen  Heinz-Jürgen Fischer 《Pure and Applied Geophysics》1969,77(1):11-20

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Über den Zusammenhang zwischen den Festigkeitshypothesen von Mohr und Griffith     

Horst Wagner 《Rock Mechanics and Rock Engineering》1969,1(2-3):105-118

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Zur Optik von Covellin     

Univ.-Doz. Dr. Kurt V. Gehlen  Dr. Horst Piller 《Contributions to Mineralogy and Petrology》1964,10(1):94-110

Zusammenfassung Im Vorwort wird die gegenwärtige Situation der quantitativen Auflichtmikroskopie kurz beleuchtet. Sie hat in letzter Zeit durch verbesserte Geräte, Meßverfahren und Fehleruntersuchungen neue Impulse erhalten.Dann wird über Messungen des Reflexionsvermögens für, und einzelne Zwischenwerte von ' an orientierten Schnitten durchCovellin-Einkristalle von Alghero berichtet, die mit einem an ein Mikroskop angebauten Spektralphotometer der Fa. Carl Zeiss, Oberkochen, im sichtbaren Spektralbereich zwischen 440 und 700 nm durchgeführt wurden. Die in Luft und Öl erhaltenen Meßwerte wurden zu Berechnungen der Brechungsindizesn, der Absorptionskoeffizientenk und der Absorptionsindizes für Covellin verwandt. Die zwischen (relativ) 2 und 11 % schwankenden Meßfehler für die Reflexionswerte wirken sich in komplizierter Weise auf die Genauigkeit der berechneten Konstanten aus. Durch zusätzliche graphische Extrapolationen gelang es, auch für den außerordentlichen Strahl zuverlässige Dispersionskurven der einzelnen Größen abzuleiten und dann für diese auch Schnitte durch ihre darstellenden Flächen zu konstruieren. Hier fällt das Verhalten des Reflexionsvermögens in Öl im Roten auf, das durch den positiven Charakter der Doppelbrechung und den gleichzeitig negativen Charakter der Doppelabsorption in diesem Wellenlängenbereich beeinflußt wird. Das Reflexionsvermögen in Öl ist für im Roten größer als in Luft! Hier sinktn auf Werte < 1,0 ab. Zur Erklärung der ungewöhnlichen optischen Eigenschaften wird auf mögliche Beziehungen zur Kristallstruktur des Covellins hingewiesen.In einem Anhang werden einzelne optische Daten für den blaubleibenden Covellin mitgeteilt; hier sinktn zum Roten hin nur auf etwa 1,50 ab.

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In the introduction, the present situation of quantitative microscopy in reflected light is characterized. This field has recently received new impulses through better equipment, better methods, and discussions of possible errors.Then, measurements of reflectivitiesR, R and some intermediate valuesR ofcovellite are discussed which were performed on oriented sections through single crystals from Alghero by means of a spectral photometer attached to a microscope (Carl Zeiss, Oberkochen) in the visible range from 440–700 nm (mµ). The values obtained in air and oil were used to calculate the optical constants: refractive indexn, absorption coefficientk, and absorption index.The errors in reflectivity values which ranged from 2–11 per cent (relative) had a complex effect on the accuracy of the calculated constants. By means of additional graphical extrapolations it was possible to obtain reliable dispersion curves of the different values also for the extraordinary ray.Finally, also sections through the different indicating surfaces were constructed. Here, especially the behavior of the reflectivity in oil in red light is interesting: it is influenced by positive birefringence and negative biabsorption at the same time. For, the reflectivity is higher in oil than in air between 635 and at least 700n. Here, nco reaches values below 1.0. For a possible explanation of the unusual optical properties the crystal structure of. covellite has to be taken into consideration.The best values obtained for covellite at four standard wavelengths are summarized in Table 3.In an appendix some optical data are given for blue-remaining covellite. This phase has a highern in the red (about 1.50).

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Herrn Professor Dr.C. W. Correns zum 70. Geburtstag gewidmet.  相似文献   

The modification of plume models to account for dry deposition     

Thomas W. Horst 《Boundary-Layer Meteorology》1984,30(1-4):413-430

The assumptions and predictions of four diffusion-deposition models are compared, and two simple plume depletion models are recommended. One model applies an analytical, constant eddy-diffusivity solution of the advection-diffusion equation as a deposition correction to the general Gaussian plume model. Predictions of this model compare moderately well with those of the surface depletion model, an exact treatment of plume depletion, and it is particularly useful for estimating the transport and deposition of settling particles. The second model is a correction to the simple source depletion model that also accounts for the change in the vertical concentration profile caused by deposition. The computational requirements of this model are similar to those of the unmodified source depletion model, while its predictions near the surface are very close to those of the surface depletion model.  相似文献   

Rheologische Gesichtspunkte bei der Verformung der Lithosphäre unter Lasten     

Dipl.-Phys. Martin Klügel  Prof. Dr. Horst J. Neugebauer 《International Journal of Earth Sciences》1981,70(1):261-270

Zusammenfassung Die Deformation der Erdoberfläche durch Auflasten ist eine Funktion der jeweiligen Last sowie der rheologisch-mechanischen Eigenschaften der Lithosphäre und des oberen Mantels der Erde.Erklärungsversuche beobachteter Deformationen als Folge von Lasten auf der Grundlage linearer rheologischer Gesetzmäßigkeiten führen im allgemeinen zu unzureichenden Resultaten. Hinzu kommen theoretische und experimentelle Resultate über das nichtlineare Materialverhalten von Gesteinen.Daher werden numerische Modellrechnungen in Ansatz gebracht, um entsprechende rheologische, strukturelle und kinematische Größen in Zusammenhang zu bringen. Diese Berechnungen erbringen deutliche Hinweise, daß der nichtlineare Theologische Ansatz sehr viel weitreichendere Erklärungen der Beobachtungen zuläßt.

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The deformation of the earth's surface in response to loads is a function of the corresponding loads as well as the rheological constitution of the lithosphere and the upper mantle.Proposed explanations of observations on the base of linear rheologies lead to unsatisfactory results. In addition theoretical and experimental considerations claim nonlinear dependence of the creep rate of rocks on the shear stress.Numerical models have been adopted to bring appropriate rheological, structural and loading conditions together. The numerical results evidently favour the nonlinear rheology statement because this assumption allows more extensive explanations of data.

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Résumé La déformation de la surface de la terre en tant que réaction due aux charges est une fonction de la charge correspondante ainsi que des propriétés rhéologico-dynamiques de la lithosphère et du manteau supérieur.Des essais d'explication de déformations sous l'effet de charge sur la base de régularités linéaires rhéologiques donnent en général des résultats non satisfaisants. A ceci s'ajoutent des résultats théoriques et expérimentaux sur le comportement non-linéaire des roches.Des calculs de modèle numériques sont adoptés pour conférer une cohésion entre les valeurs rhéologiques, structurelles et cinématique correspondantes. Ces calculs apportents des indications claires telles, que la mise en équation non-linéare rhéologique permet des explications beaucoup plus générales des observations.

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Hydrogeochemical and Flow Modeling of Aquitard Percolation in the Cariri Valley-Northeast Brazil     

Carlos José Freire Machado  Maria Marlúcia Freitas Santiago  Luiz Alberto Ribeiro Mendonça  Horst Frischkorn  Josué Mendes Filho 《Aquatic Geochemistry》2007,13(2):187-196

Flow modeling and hydrogeochemical inversion calculations were performed on the aquifer systems of the Crato-Juazeiro Graben in the Araripe Sedimentary Basin of the Cariri Valley, Northeast Brazil, in order to assess aquifer interconnections through an aquitard of the Araripe Plateau. Steady state hydraulic head numeric calculations with the finite difference method used Modflow software with hydrologically based boundary conditions and a piezometric surface as initial condition. Hydrogeochemical inversion with PHREEQC was performed for two water samples representing typical initial and final waters along the flow path. Flow simulation shows that approximately 20% of all recharge water from the superior aquifer system passes through the Santana aquitard reaching the middle aquifer system. Quantification of mineral dissolution/precipitation processes, ion exchange and microbiological redox reactions taking place in the aquifer systems also indicates hydraulic interconnection of the superior and middle aquifer systems through the Santana aquitard.  相似文献   

Li abundances in eclogite minerals: a clue to a crustal or mantle origin?     

Alan B. Woodland  Hans-Michael Seitz  Rainer Altherr  Horst Marschall  Bettina Olker  Thomas Ludwig 《Contributions to Mineralogy and Petrology》2002,143(5):587-601

The mineral phases of 33 eclogite and garnet clinopyroxenite samples from various tectonic settings were analysed for Li by secondary ion mass spectrometry (SIMS). In all samples, Li is preferentially incorporated into clinopyroxene (0.4 to 80 µg/g), whereas co-existing garnet contains only minor amounts of Li (0.01 to 3.7 µg/g). When present, glaucophane shows Li abundances which are similar to those of clinopyroxene, but phengite contains significantly less Li than clinopyroxene. Additional phases, such as amphibole, quartz, clinozoisite and kyanite, have low Li concentrations (<1 µg/g). No correlation is apparent between the Li contents and major-element compositions of clinopyroxene or garnet. On the basis of both measured Li concentrations in clinopyroxene and estimated Li abundances in the whole rocks, the investigated samples can be subdivided into high-Li and low-Li groups. These groups coincide with the mode of origin of the rocks. Metabasaltic (metagabbroic) eclogites from high-pressure terranes belong to the high-Li group whereas, except for one eclogite, all kimberlite- and basanite-hosted xenoliths have low Li contents. Samples from eclogites and garnet clinopyroxenites associated with orogenic peridotites fall into both groups. It is suggested that the high-Li eclogites originated from basaltic oceanic crust whereby the notable Li enrichment of some samples was probably caused by low-temperature hydrothermal alteration prior to subduction. Furthermore, the low-Li eclogites and garnet clinopyroxenites may represent high-pressure cumulates from mafic melts percolating through the mantle.  相似文献   

Avoidance of new conflict situations in the East-West-road-transport     

Horst Hermann Binnenbruck 《GeoJournal》1977,1(3):61-64

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Structural and other contributions to the third-law entropies of silicates     

Horst H. Ulbrich  David R. Waldbaum 《Geochimica et cosmochimica acta》1976,40(1):1-24

The true third-law entropies of many minerals are frequently quite different from those values derived from calorimetric measurements. The discrepancy can usually be attributed to neglected residual or unextracted entropies related either to site-mixing and molecular disorders or to the lack of significant magnetic ordering at those temperatures reached by the heat capacity measurements. A literature review indicates that many silicates present site-mixing and vacancies in one or several of their crystallographic sites. The effect on entropy is well known in feldspars, but residual entropies of similar or greater magnitudes are also present in many amphiboles, micas, chlorites, zeolites, scapolites, feldspathoids, and other silicates. Less conspicuously, disorder in water molecules or hydrogen bonding may be responsible for yet another frequently overlooked entropy contribution. Unextracted entropy results from limited heat capacity measurements so that magnetic ordering effects to be expected in minerals with transition metals are either not registered or only incompletely recorded. In some cases, significant magnetic ordering probably only takes place at temperatures well below 15 K.The discussion in this paper centers on the causes resulting in discrepancies between calorimetric and third-law entropies. A set of tables reproduces the crystallographic information for most important rock-forming silicates and indicates the entropy contribution arising from site-mixing and vacancies, and possible magnetic ordering in those substances with transition metals. In addition, most elements appear in several isotopic forms, and it is this effect that gives rise to isotopic site-mixing and thus to another configurational entropy. It can on the whole be neglected. A discussion centered on the system fayalite-iron oxides (wüstite, hematite, magnetite) indicates the uncertainties involved in deriving third-law entropies from either equilibrium data or calorimetric investigations, which is especially relevant when dealing with substances presenting vacancies (wüstite), transition metals, and the possibility of magnetic ordering. The published entropies of many minerals are probably only approximations to true third-law values and should be checked against structural and magnetic information.  相似文献   

Cleaning Up a 3‐Mile‐Long Groundwater Plume: It Can Be Done          下载免费PDF全文

Suthan Suthersan  Paul Carroll  Matthew Schnobrich  John Horst  Scott Potter  Lynden Peters 《Ground Water Monitoring & Remediation》2015,35(4):27-35

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