Arsenolite: a quasi-hydrostatic solid pressure transmitting medium

This study reports the experimental characterization of the hydrostatic properties of arsenolite (As4O6), a molecular solid which is one of the softest minerals in the absence of hydrogen bonding. The high compressibility of arsenolite and its stability up to 15GPa have been proved by x-ray diffraction measurements, and the progressive loss of hydrostaticity with increasing pressure up to 20GPa has been monitored by ruby photoluminescence. Arsenolite has been found to exhibit hydrostatic behavior up to 2.5GPa and a quasi-hydrostatic behavior up to 10GPa at room temperature. This result opens the way to explore other molecular solids as possible quasi-hydrostatic pressure-transmitting media. The validity of arsenolite as an insulating, stable, non-penetrating and quasi-hydrostatic medium is explored by the study of the x-ray diffraction of zeolite ITQ-29 at high pressure.This work has been performed with financial support from Spanish MINECO under projects MAT2013-46649-C4-2/3-P and MAT2015-71070-REDC. JAS acknowledges the 'Ramon y Cajal' fellowship program for financial support. We also thank D Calatayud, J J Garcia, T M Godoy, A Zapata, and A Cuenca for fruitful discussions. The authors thank ALBA light source for beam allocation at beamline MSPD. JLJ and FR acknowledge financial support through the SEV-2012-0267, Consolider Ingenio 2010-Multicat (CSD-2009-0050) and MAT2015-71842-P (MINECO/FEDER) projects.Sans-Tresserras, JÁ.; Manjón, FJ.; Popescu, C.; Muñoz, A.; Rodríguez-Hernández, P.; Jordá, JL.; Rey Garcia, F. (2016). Arsenolite: a quasi-hydrostatic solid pressure transmitting medium. Journal of Physics: Condensed Matter. 28(47):475403-1-475403-7. doi:10.1088/0953-8984/28/47/475403S475403-1475403-7284

Effect of Gamma Irradiation on Cement Composites Observed with XRD and SEM Methods in the Range of Radiation Dose 0-1409 MGy

The effect of gamma radiation in the range of 0-1409 MGy on the structure of a new mineral additive to cement based composites was investigated in the perspective of employing them as radioactive waste protection material. According to the authors knowledge, it is the first paper dealing with observations of the cement matrix, both pure and modified, treated with so giant radiation dose. The absorption of gamma radiation modifies the morphology of the additive grains, causes decomposition of cement hydrates and clinker relicts in cement paste containing the additive at twice higher radiation dose than that inducing the decomposition of the reference pure cement paste and the cement paste containing pozzolane additives