La thixotropie (TIPE, stage de recherche et explications)

Qu’est-ce donc que ce mot barbare? Sous ce terme scientifique se cache un phénomène assez connu, globalement celui des sables mouvants. On dit d’un matériau qu’il est thixotrope si, en réponse à une contrainte (agitation mécanique, ondes sismiques, cisaillment) sa … Lire la suite

Mineralogy and Petrology of Comet 81P/Wild 2 Nucleus Samples

NEW PUBLICATION IN SCIENCE The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, … Lire la suite

Equation of state and phase transition in KAlSi3O8 hollandite at high pressure

NEW PUBLICATION IN AMERICAN MINERALOGIST The tetragonal hollandite structure (KAlSi3O8 hollandite) has been studied up to 32 GPa at room temperature using high-pressure in-situ X-ray diffraction techniques. A phase transformation from tetragonal I4/m phase to a new phase was found … Lire la suite

A new high-pressure form of KAlSi3O8 under lower mantle conditions

NEW PUBLICATION In situ X-ray diffraction measurements have been made on KAlSi3O8 hollandite using diamond anvil cell and multianvil apparatus combined with synchrotron radiation. Both of the measurements with different techniques demonstrated that K-hollandite transforms to a new highpressure phase … Lire la suite