low water-wettability and oxidation resistance of graphite have limited its application in carbon containing refractory castables. the aims of this study were improvement of water-wettability and the oxidation resistance of natural flaky graphite by applying an oxide coating on its surface. to develop the coating, magnesium aluminate spinel sol was formulated via a citrate-nitrate route and gra...

kuh-e-siah is located in the north of gavkhuni lagoon and east of the varzaneh (se of isfahan) and is a part of urumieh-dokhtar magmatic arc (udma). the volcanic rocks of this area are vesicular basalt and basaltic andesite with late miocene age. the most common textures of these rocks are porphyry, microlitic porphyritic, hyaloporphyric and vesicular. plagioclase, olivine and clinopyroxene are...

Type C inclusions are plagioclase-rich, Ca-, Al-rich inclusions found in carbonaceous chondrites. They formed as solid condensates which were later melted in an event that destroyed the original condensate grains. Neither the melting event nor secondary alteration had a significant effect on bulk composition. Two stages in the condensation history can be discerned on the basis of major element ...

This work describes the production of magnesia-alumina spinel using microwaves as energy source. The microwave energy was supplied by means of an 800 W magnetron operating at 2.45 GHz. The microstructure and the mineral composition were studied by means of SEM and X-Ray diffraction respectively. The resultant product shown sintered zone and incipient smelting of the reagents meaning that microw...

The elasticity of high-pressure mantle phases may be characterized by crystal chemically similar compounds. Analogue compounds available as single crystals yield the most reliable elastic constant data. The single-crystal elastic constants of pleonaste and hercynite spinel, rutile-structure germanium dioxide, and spessartite-almandine garnet are studied, in most cases as a function of pressure ...

Introduction: In 1999 we calculated the production of spinel-bearing silicate liquid droplets from the condensing fireball produced in the Chicxulub Cretaceous/Tertiary impact [1], based on predicted plume compositions for 4 vertical impacts [2]. Recent calculations for oblique impacts [3], following only the first 5 post-impact seconds, predict the contributions of impactor [4], continental cr...

The development of water oxidation catalysts (WOCs) to replace costly noble metals in commercial electrolyzers and solar fuel cells is an unmet need that is preventing the global development of hydrogen fuel technologies. Two of the main challenges in realizing catalytic water splitting are lowering the substantial overpotential that is required to achieve practical operating current densities ...

Synopsis: The oxygen fugacity of the basaltic martian meteorites has been calculated from thermodynamic models involving spinel-ilmenite equilibria. The wide range of estimates, from near the IW buffer to near QFM, may be explained by mixing of mantlederived melts with oxidized material in the martian crust. Possible oxidized crustal end-members are considered. Analytical Method and Results: Sp...