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By solving the Euler hydrodynamical equations we have obtained closed form solutions for the angular velocities and pressures of a three stratified non-confocal heterogeneous oblate spheroid. Limiting and particular solutions cases, such as a spheroid with N layers, a stratified spheroid with the same eccentricities, as well as confocal layered spheroids are also explicitly written down. As an application, we have numerically estimated planet Earth's outer and inner cores' ellipticities to be o=1/413.318 and i=1/424.616, respectively. These Earth's ellipticities values are in good agreement with those found in the literature. 相似文献
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Mary R. Reid Jorge A. Vazquez Axel K. Schmitt 《Contributions to Mineralogy and Petrology》2011,161(2):293-311
Zircon has the outstanding capacity to record chronological, thermal, and chemical information, including the storage history
of zoned silicic magma reservoirs like the one responsible for the Bishop Tuff of eastern California, USA. Our novel ion microprobe
approach reveals that Bishop zircon rims with diverse chemical characteristics surround intermediate domains with broadly
similar compositions. The highest Y, REE, U, and Th concentrations tend to accompany the largest excesses in Y + REE3+:P beyond what can be explained by xenotime substitution in zircon. Apparent Ti-in-zircon temperatures of <720°C for zircon
rims are distinctly lower than most of the range in eruption temperatures, as estimated from FeTi-oxide equilibria and zircon
solubility at quench. While permissive of crystallization of zircon at near-solidus conditions, the low Ti-in-zircon temperatures
are probably better explained by sources of inaccuracy in the temperature estimates. After apparently nucleating from different
melts, zircons from across the Bishop Tuff compositional spectrum may have evolved to broadly similar chemical and thermal
conditions and therefore it is possible that there was no significant thermal gradient in the magma reservoir at some stage
in its evolution. There is also no compelling evidence for punctuated heat ± chemical influxes during the intermediate stages
of zircon growth. Judging by the zircon record, the main volume of the erupted magma evolved normally by secular cooling but
the latest erupted portion is characterized by a reversal in chemistry that appears to indicate perfusion of the magma reservoir
by—or zircon entrainment in—a less evolved melt from the one in which the zircons had previously resided. 相似文献
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Sunspot drawings made by Galileo Galilei in 1612 are used to derive the law of differential rotation at that time. The main
interest of the work is during the time of observations, just at the beginning of telescopic observations and some decades
before the Maunder Minimum (1645 – 1715), a period where the sunspots almost disappeared from the solar surface. For this
purpose we have carried out careful corrections of the different sources of errors derived from the observing technique. By
comparing with other results of the same century, a significant difference is only detected by comparing with data corresponding
to the deep Maunder Minimum (Paris Observatory drawings). The characteristics of the solar differential rotation, and extrapolating
the behavior of solar activity, did not differ before or after the Maunder Minimum. We also include an analysis of hitherto
ignored sunspot drawings by N. Bion made in October and November 1672. 相似文献
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Jacob B. Lowenstern Heather Bleick Jorge A. Vazquez Jonathan M. Castro Peter B. Larson 《Bulletin of Volcanology》2012,74(10):2303-2319
We investigated the distribution of Cl, F, Li, and Be in pumices, obsidians, and crystallized dome rocks at Chaitén volcano in 2008?C2009 in order to explore the behavior of these elements during explosive and effusive volcanic activity. Electron and ion microprobe analyses of matrix and inclusion glasses from pumice, obsidian, and microlite-rich dome rock indicate that Cl and other elements were lost primarily during crystallization of the rhyolitic dome after it had approached the surface. Glass in pumice and microlite-free obsidian has 888?±?121?ppm Cl, whereas residual glass in evolved microlite-rich dome rock generally retains less Cl (as low as <100?ppm). Estimated Cl losses were likely >0.7?Mt Cl, with a potential maximum of 1.8?Mt for the entire 0.8-km3 dome. Elemental variations reflect an integrated bulk distribution ratio for Cl?>?1.7 (1.7 times more Cl was degassed or incorporated into crystals than remained in the melt). Because Cl is lost dominantly as the very last H2O is degassed, and Cl is minimally (if at all) partitioned into microlites, the integrated vapor/melt distribution ratio for Cl exceeds 200 (200 times more Cl in the evolved vapor than in the melt). Cl is likely lost as HCl, which is readily partitioned into magmatic vapor at low pressure. Cl loss is accelerated by the change in the composition of the residual melt due to microlite growth. Cl loss also may be affected by open-system gas fluxing. Integrated vapor-melt distribution ratios for Li, F, and Be all exceed 1,000. On degassing, an unknown fraction of these volatiles could be immediately dissolved in rainwater. 相似文献
16.
Lourdes Vazquez‐Gomez Achille de Battisti Sergio Ferro Monica Cerro Silvia Reyna Carlos A. Martínez‐Huitle Marco A. Quiroz 《洁净——土壤、空气、水》2012,40(4):408-415
The electrochemical oxidation (EO) of diethyl phthalate (DEP) in aqueous solution was studied at Pb/PbO2 and Ti/SnO2 anode materials under galvanostatic‐experimental conditions. Results obtained clearly demonstrated that the anode plays a significant role for the optimization of the oxidation process, deciding the mechanisms and by‐products formed. DEP and by‐products of oxidation were also analyzed during various stages of the electrolysis reaction by HPLC and GC/MS techniques. Before the analysis by GC/MS technique, the samples were treated by solid phase microextraction (SPME) in order to concentrate the compounds from the reaction solution and identify all electrolysis intermediates. Current efficiencies (instantaneous current efficiency; ICE and total current efficiency; TCE) achieved during EO experiments were dependent on anode used and current density (20–40 mA cm?2) at 40°C. The results obtained demonstrated that the environmental electrochemical methods can be a feasible alternative for the wastewater treatment containing hazardous phthalates. 相似文献
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Bedload and river morphology interact in a strong feedback manner. Bedload conditions the development of river morphology along different space and time scales; however, by concentrating the flow in preferential paths, a given morphology controls bedload for a given discharge. As bedload is a non‐linear response of shear stress, local morphology is likely to have a strong impact on bedload prediction when the shear stress is averaged over the section, as is usually done. This was investigated by comparing bedload measured in different bed morphologies (step‐pool, plane bed, riffle‐pool, braiding, and sand beds), with bedload measured in narrow flumes in the absence of any bed form, used here as a reference. The initial methodology consisted of fitting a bedload equation to the flume data. Secondly, the morphological signature of each river was studied as the distance to this referent equation. It was concluded that each morphology affects bedload in a different way. For a given average grain shear stress, the larger the river, the larger the deviation from the flume transport. Narrow streams are those morphologies that behave more like flumes; this is particularly true with flat beds, whereas results deviate from flumes to a greater extent in step‐pools. The riffle‐pool's morphology impacts bedload at different levels depending on the degree of bar development, considered here through the ratio D84/D50 which is used as a proxy for the local bed patchiness and morphology. In braiding rivers morphological effects are important but difficult to assess because width is dependent on transport rate. Bed morphology was found to have negligible effects in sand bed rivers where the Shields stress is usually sufficiently high to minimize the non‐linearity effects when hydraulics is averaged over the section. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Ocean Dynamics - Wind dominates the ocean surface circulation in the subtropical coastal upwelling regions. Although the wind events in these regions are mostly favorable for upwelling, other types... 相似文献
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