Theorie und Vorhersage der Hochnebelbildung in Wiener Becken     

Julius Drimmel 《Meteorology and Atmospheric Physics》1958,10(4):410-414

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Ergänzung zur Arbeit: „Zur Physik der Taubildung an der Erdoberfläche”     

Julius Drimmel 《Meteorology and Atmospheric Physics》1957,10(1):94-95

Zusammenfassung In einer früheren Arbeit wurde auf Grund der Voraussetzung eines höhenkonstanten Austauschkoeffizienten eine Tauformel abgeleitet und diskutiert, die für größere Turbulenz Abweichungen von der Wirklichkeit zeigt. Durch zusätzliche Überlegungen werden nun die nachteiligen Folgen des Rechnens mitA = const. behoben.  相似文献   

Disequilibrium of strontium isotopes between mineral phases of parental rocks during magma genesis — a discussion     

Dennis O. Nelson  E.Julius Dasch 《Journal of Volcanology and Geothermal Research》1976,1(2):183-191

Consideration of available diffusion rate data at high temperatures and pressures casts serious doubt on disequilibrium melting as a mechanism by which variable ⁸⁷Sr/⁸⁶Sr ratios can be generated in basaltic melts whose parental rocks were at or below the low-velocity layer for more than a million years. Diffusion rates are orders of magnitude faster in these regions than in the upper lithosphere and lower crust. Ultramafic fragments with minerals in isotopic disequilibrium are pieces of the upper lithosphere, where elapsed time and comparatively low temperatures have resulted in the observed disequilibrium. Regional isotopic heterogeneity in the mantle is the most reasonable explanation for isotopic variability found in abyssal basalts.  相似文献   

A strontium isotope evolution model for cenozoic magma genesis,Estern Great Basin,U.S.A.     

R. B. Scott  R. W. Nesbitt  E. Julius Dasch  R. L. Armstrong 《Bulletin of Volcanology》1971,35(1):1-26

Cenozoic volcanism in the Great Basin is characterized by an outward migration of volcanic centers with time from a centrally located core region, a gradational decrease in the initial Sr⁸⁷/Sr⁸⁶ ratio with decreasing age and increasing distance from the core, and a progressive change from calc-alkalic core rocks to more alkalic basin margin rocks. Generally each volcanic center erupted copious silicic ignimbrites followed by small amounts of basalt and andesite. The Sr⁸²/Sr⁸⁶ ratio for old core rocks is about 0.709 and the ratio for young basin margin rocks is about 0.705. Spatially and temporally related silicic and mafic suites have essentially the same Sr⁸⁷/Sr⁸⁶ ratios. The locus of older volcanism of the core region was the intersection of a north-south trending axis of crustal extension and high heat flow with the northeast trending relic thermal ridge of the Mesozoic metamorphic hinterland of the Sevier Orogenic Belt. Derivation of the Great Basin magmas directly from mantle with modification by crustal contamination seems unlikely. Initial melting of lower crustal rocks probably occurred as a response to decrease in confining pressure related to crustal extension. Volcanism was probably also a consequence of the regional increase in the geothermal gradient that is now responsible for the high heat flow of the Basin and Range Province. High Sr isotopic ratios of the older core volcanic rocks suggests that conditions suitable for the production of silicic magmas by partial fusion of the crust reached higher levels within the crust during initial volcanism than during production of later magmas with lower isotopic ratios and more alkaline chemistry. As the Great Basin became increasingly attenuated, progressively lower portions of the crust along basin margins were exposed to conditions suitable for magma genesis. The core region became exhausted in low temperature melting components, and volcanism ceased in the core before nearby areas had completed the silicic-mafic eruption cycle leading to their own exhaustion of crustal magma sources.  相似文献   

Application of general circulation models to the study of stratospheric ozone     

London  Julius  Park  Jae 《Pure and Applied Geophysics》1973,106(1):1611-1617

Summary Observations of the ozone distribution indicate that modifications are required to the photochemical theory. These modifications involve ozone destruction by hydrogen and nitrogen products and ozone transport (both vertical and horizontal) due to atmospheric motions in the stratosphere. If the photochemical terms in the ozone continuity equation are omitted, changes due to atmospheric transport alone can be evaluated.Numerical computations were made of the three-dimensional wind structure as derived from the 12-layer (0–36 km) General Circulation Model developed by NCAR. The results showed that ozone is transported from the equatorial stratosphere poleward and downward in both hemispheres. The horizontal transport is primarily by the Hadley Cell in the tropics and by large-scale eddies in mid and high latitudes. The dominant mechanism for ozone transport are found to be similar to those derived for the horizontal heat and momentum transport found in other general circulation studies.  相似文献   

Sheet silicates of the Lawler Peak granite,Arizona: chemistry,structural variations,and exsolution     

Embaie A. Ferrow  David London  Kathleen S. Goodman  David R. Veblen 《Contributions to Mineralogy and Petrology》1990,105(5):491-501

Coarse-grained muscovite, biotite, and chlorite from the Lawler Peak granite, Yavapai County, Arizona, have been studied with electron microprobe analysis, powder X-ray diffraction, transmission electron microscopy (TEM), electron diffraction, and analytical TEM methods. All three sheet silicates exhibit multiple polytypes and an abundance of stacking faults and dislocations. Chlorite formed by subsolidus replacement of biotite. Muscovite also may have formed by replacement of biotite and other minerals, but there is no clear microstructural evidence to support either a primary or secondary origin for the coarse-grained muscovite. X-ray and electron diffraction reveal that the muscovite consists of two separate phases, which give rise to splitting of diffraction maxima. TEM experiments suggest that the two components resulted from exsolution, which produced two symmetry-related sets of irrationally oriented lamellae with a wavelength averaging about 10 nm. Exsolution occurred in both 1M and 2M₁ muscovite. Although the lamellae are too small to analyze directly, the muscovite bulk composition and structural data are consistent with the separation of celadonitic and muscovite components.  相似文献   

Melt-vapor solubilities and elemental partitioning in peraluminous granite-pegmatite systems: experimental results with Macusani glass at 200 MPa   总被引：5，自引：1，他引：5  

David London  Richard L. Hervig  George B. Morgan VI 《Contributions to Mineralogy and Petrology》1988,99(3):360-373

Vapor-saturated experiments at 200 MPa with peraluminous, lithophile-element-rich rhyolite obsidian from Macusani, Peru, reveal high miscibility of H₂O and silicate melt components. The H₂O content of melt at saturation (11.5+-0.5 wt.%) is almost twice that predicted by existing melt speciation models. The corresponding solubility of melt components in vapor decreases from 15 wt.% dissolved solids (750°–775° C) to 9 wt.% at 600° C. With regard to major and most minor components, macusanite melt dissolves congruently in vapor. Among the elements studied (B, P, F, Li, Rb, Cs, Be, Sr, Ba, Nb, Zr, Hf, Y, Pb, Th, U, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm), only boron has a vapor/melt partition coefficient (D[B]) consistently 1 at superliquidus temperatures (>645° C). Phosphorus and fluorine behave similarly, with D[P] and D[F]<0.5. Little or no significant vapor/melt fractionation is evident among most periodic groups (alkalis, alkaline earths, Zr/Hf, or the REE). The temperature dependence of vapor/melt partition coefficients is generally greatest for cations with charge +3 (except Nb and U); most vapor/melt partition coefficients for trace elements increase with decreasing temperature to the liquidus. Crystallization proceeds by condensation of crystalline phases from vapor; most coexisting melts are aphyric. Changes in the major element content of melt are dominated by the mineral assemblage crystallized from vapor, which includes subequal proportions of white mica, quartz, albite, and orthoclase. The volumetric proportion of (mica + or-thoclase)/albite increases slightly with decreasing T, creating a sodic, alkaline vapor. Vapor deposition of topaz (T500° C), which consumes F from melt, returns K/Na ratios of melt to near unity with the vapor-deposition of albite. The abundances of most trace elements in residual melt change little with the crystallization of major phases, but in some cases are strongly controlled by the deposition of accessory phases including apatite (T550° C), which depletes the melt in P and REE. Below the liquidus, boron increasingly favors the vapor over melt with decreasing temperatures.  相似文献   

On the Eulerian source-receptor relationship     

Hsiao-Ming Hsu  Julius S. Chang 《Journal of Atmospheric Chemistry》1987,5(1):103-124

A new approach is proposed to delineate the source-receptor relationship in an Eulerian model. A small, unique oscillatory signal is superimposed on each emission source in the airshed. At receptor sites the concentration time series are analyzed by a Fourier transform to give the amplitudefrequency spectrum. Distinct peaks found in the spectrum are identified at the emission frequencies. The amplitude of the spectrum at the source frequency represents the individual contribution from that emitter. Various atmospheric transport and diffusion models are solved to show the effects of different physical and chemical processes on the oscillatory signals. Both analytical and numerical solutions are used to demonstrate the performance of the method.The National Center for Atmospheric Research is sponsored by the National Science Foundation.  相似文献   

One‐Pot Synthesis of Xanthate‐Functionalized Cellulose for the Detection of Micromolar Copper(II) and Nickel(II) Ions     

Kim Greis  Kevin Bethke  Julius B. Stückrath  Tjark T. K. Ingber  Suresh Valiyaveettil  Klaus Rademann 《洁净——土壤、空气、水》2019,47(9)

A one‐pot synthesis and application of cellulose‐based sensors to efficiently detect various toxic metal ions in aqueous solutions in micromolar quantities is reported. Cellulose microfibers have been functionalized with carbon disulfide in alkaline solution to form cellulose xanthate. The material detects several toxic metal ions such as copper, nickel, or cobalt ions through color change detectable by the naked eye. The optical sensor can be used as an ideal flash test for assessing the quality of drinking water.  相似文献   

Wind tunnel and field calibration of five aeolian sand traps   总被引：4，自引：0，他引：4  

Dirk Goossens  Zvi Offer  Gary London 《Geomorphology》2000,35(3-4)

The efficiency of five aeolian sand samplers was tested via wind tunnel experiments and field measurements. The samplers were: the Big Spring Number Eight (BSNE) sampler, the Modified Wilson and Cooke (MWAC) sampler, the Suspended Sediment Trap (SUSTRA), the Pollet catcher (POLCA), and the saltiphone. In the wind tunnel, the samplers were calibrated against an isokinetic sampler (a modified Sartorius SM 16711 sampler with adjustable flow rate), and this for three sand types (median diameter: 132, 194 and 287 μm) and five wind speeds (ranging from 6.6 to 14.4 m s⁻¹). In the field, seven calibration tests of two weeks each were conducted. The absolute efficiencies of the BSNE, MWAC and POLCA are more or less comparable and vary between 70% and 120%, depending on sediment size and wind speed. For the SUSTRA, the efficiency is somewhat lower for fine sands and for wind speeds above 11 m s⁻¹. Finally, the saltiphone can accurately detect the periods of saltation transport, but in its current version, the instrument is not accurate when measuring the absolute saltation flux. The most recommendable sampler in the test is the MWAC, not only because of its high efficiency, but also because its efficiency is independent of wind speed.  相似文献