نتایج جستجو برای: earths crust

تعداد نتایج: 11121  

Journal: :The Journal of Geology 1901

Journal: :Tetsu-to-Hagane 1984

Journal: :The Journal of clinical investigation 1942
S B Beaser A Segel L Vandam

The recent interest in the anticoagulant action of heparin has led us to seek a substance which might be similar in action but less expensive and simpler to administer. The anticoagulant effect of various rare earths given intravenously has been studied in lower animals (1, 2, 3). As far back as 1920, Esnault and Brou (4), and Grenet and Drouin (5) injected rare earths in 40 to 100 mgm. doses i...

2011
Koichiro Umemoto Renata M. Wentzcovitch

a r t i c l e i n f o Keywords: pressure-induced phase transition postperovskite super-Earth 10 solar giants first principles The fate of MgSiO 3 post-perovskite under TPa pressures is key information for understanding and modeling interiors of super-Earths-type exoplanets and solar giants' cores. Here, we report a dissociation of MgSiO 3 post-perovskite into CsCl-type MgO and P2 1 /c-type MgSi...

2011
Bradley R. Hacker Peter B. Kelemen Mark D. Behn

a r t i c l e i n f o Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic gneisses that are less dense than peridotite but more dense than the uppe...

2014
Brice-Olivier Demory

Exoplanet research focusing on the characterization of super-Earths is currently limited to the handful of targets orbiting bright stars that are amenable to detailed study. This Letter proposes to look at alternative avenues to probe the surface and atmospheric properties of this category of planets, known to be ubiquitous in our galaxy. I conduct Markov Chain Monte Carlo light-curves analyses...

2015
Sofía Riaño Koen Binnemans

A procedure for the efficient extraction and separation of rare earths and other valuable elements from used NdFeB permanent magnets is presented. In a first step, an iron free leachate is prepared from an used magnet using nitric acid. Cobalt is separated through a liquid–liquid extraction in aqueous nitrate media using as organic phase the ionic liquid trihexyl(tetradecyl)phosphonium nitrate ...

2013
F. Habashi

Although most of the rare earth metals were discovered in Sweden, the industrialisation started in the Austrian Empire. This was due to the fact that the Swedish chemist Jons Fridrik Bahr (1815–1875) from Uppsala went to Heidelberg in Germany in 1855 to analyse some rare earth minerals by the spectroscope discovered recently by chemistry professor Robert Bunsen (1811– 1899) and his colleague ph...

2010
Erik Asphaug

It is assumed in models of terrestrial planet formation that colliding bodies simply merge. From this the dynamical and chemical properties (and habitability) of finished planets have been computed, and our own and other planetary systems compared to the results of these calculations. But efficient mergers may be exceptions to the rule, for the similar-sized collisions (SSCs) that dominate terr...

Journal: :Isis; an international review devoted to the history of science and its cultural influences 2015
Christián Carlos Carman James Evans

In the third century B.C.E., Eratosthenes of Cyrene made a famous measurement of the circumference of the Earth. This was not the first such measurement, but it is the earliest for which significant details are preserved. Cleomedes gives a short account of Eratosthenes' method, his numerical assumptions, and the final result of 250,000 stades. However, many ancient sources attribute to Eratosth...

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