Petrographical and Mineralogical Applications of Raman Mapping

Raman spectroscopy has undergone rapid development over the last few decades. The ability to acquire a spectrum in only a few tens of milliseconds allows use of Raman mapping as a routine technique. However, with respect to classical single spectrum measurement, this technique is not still as widely used as it could be, in particular for mineralogy and petrography. Here, we explain the advantages of Raman mapping for obtaining additional information compared to single spot analyses. The principle and the limits of the technique are first explained in 2D and 3D. Data processing techniques are then described using different types of rocks and minerals to demonstrate the utility of Raman mapping for obtaining information about the general composition, identification of small phases, as well as for distinguishing minerals that are spectrally very close. More “exotic” uses of the collected signal are also described. Finally, a gallery of images from representative samples is used to illustrate the discussion

Acoustic damping and dispersion in vitreous germanium oxide

New Brillouin scattering measurements of velocity and attenuation of sound in the hypersonic regime are presented. The data are analyzed together with the literature results at sonic and ultrasonic frequencies. As usual, thermally activated relaxation of structural entities describes the attenuation at sonic and ultrasonic frequencies. As already shown in vitreous silica, we conclude that the damping by network viscosity, resulting from relaxation of thermal phonons, must be taken into account to describe the attenuation at hypersonic frequencies. In addition, the bare velocity obtained by subtracting to the experimental data the effect of the two above mechanisms is constant for temperatures below 250 K, but increases almost linearly above, up to the glass transition temperature. This might indicate the presence of a progressive local polyamorphic transition, as already suggested for vitreous silica.Comment: 14 pages, 8 figure

Evaluation of T2G band intensity distribution across a surface of an UO2 ceramic

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Field remote Stokes/anti-Stokes Raman characterization of sulfur in hydrothermal vents

To study the dynamics of active volcanic environments, minerals involved in fresh lava flows are a nice probe and Raman spectroscopy is an excellent tool for their characterization. Because of the highly hostile environment linked to volcanic activity, studying lava cooling and weathering needs remote setups and specific procedures dedicated to medium‐high temperature targets. In this paper, we present the remote Raman characterization of sulfur produce by the fumarolic activity at Solfatara crater (Phlegraean Fields, Italy). Two medium temperature sites (280–380 K) were probed with two different Raman setups. For both, β‐sulfur is the prominent type in the entire temperature range and the absolute local temperature of the sulfur was remotely estimated by mean of a Stokes/anti‐Stokes procedure with ±10 K uncertainty. These results represent a good starting point for the development of new setups and protocols aimed to an increase of both measurement distance and temperature range.Published1385-13944V. Processi pre-eruttivi1TR. GeorisorseJCR Journa

Réflexion sur la place des basses technologies dans la Recherche du XXI ème siècle

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Where should I bake bread? GIS-based planning of solar thermal bakeries and the socio-cultural dimension of energy transition

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Where should I bake bread? GIS-based planning of solar thermal bakeries and the socio-cultural dimension of energy transition

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Low-tech lab Péi -Vers un régime technologique low-tech

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Multi-scale variability analysis of time series in Geophysics by using the empirical mode decomposition

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