Equation of state of liquid mercury to 520 K and 7 GPa from acoustic velocity measurements

Ultrafast acoustics measurements on liquid mercury have been performed at high pressure and temperature in a diamond anvil cell using picosecond acoustic interferometry. We extract the density of mercury from adiabatic sound velocities using a numerical iterative procedure. We also report the pressure and temperature dependence of the thermal expansion, isothermal and adiabatic compressibility, bulk modulus, and pressure derivative of the latter up to 7 GPa and 520 K. We finally show that the sound velocity follows a scaling law as a function of density in the overall measured metallic state. (C) 2014 AIP Publishing LLC

Rotating tomography Paris-Edinburgh cell:a novel portable press for micro-tomographic 4-D imaging at extreme pressure/temperature/stress conditions

International audienceThis paper presents details of instrumental development to extend synchrotron X-ray microtomography techniques to in situ studies under static compression (high pressure), shear stress or the both conditions at simultaneous high temperatures. To achieve this, a new rotating tomography Paris–Edinburgh cell has been developed. This ultra-compact portable device easily and successfully adapted to various multi-modal synchrotron experimental set-up at ESRF, SOLEIL and DIAMOND is explained in detail. An in-depth description of proof of concept first experiments performed on a high resolution imaging beamline is then given, which illustrate the efficiency of the set-up and the data quality that can be obtained

Thermodynamic properties of liquid gallium from picosecond acoustic velocity measurements

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Sound velocity of iron up to 152 GPa by picosecond acoustics in diamond anvil cell

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Comparative ascaroside profiling of Caenorhabditis exometabolomes reveals species-specific (omega) and (omega – 2)-hydroxylation downstream of peroxisomal beta-oxidation

Chemical communication in nematodes, such as the model organism Caenorhabditis elegans, is modulated by a variety of glycosides based on the dideoxysugar L-ascarylose. Comparative ascaroside profiling of nematode exometabolome extracts using a GC-EIMS screen reveals that several basic components including ascr#1 (asc-C7), ascr#2 (asc-C6-MK), ascr#3 (asc- DC9), ascr#5 (asc-ωC3), and ascr#10 (asc-C9) are highly conserved among the Caenorhabditis. Three novel, side chain hydroxylated ascaroside derivatives were exclusively detected in the distantly related C. nigoni and C. afra. Molecular structures of these speciesspecific, putative signaling molecules were elucidated by NMR spectroscopy and confirmed by total synthesis and chemical correlations. Biological activities were evaluated using attraction assays. The identification of (ω)- and (ω – 2)-hydroxyacyl ascarosides demonstrates how GC-EIMS-based ascaroside profiling facilitates the detection of novel ascaroside components and exemplifies how species-specific hydroxylation of ascaroside aglycones downstream of peroxisomal β-oxidation increases the structural diversity of this highly conserved class of nematode signaling molecules

Picosecond acoustics method for measuring the thermodynamical properties of solids and liquids at high pressure and high temperature

Based on the original combination of picosecond acoustics and diamond anvils cell, recent improvements to accurately measure hypersonic sound velocities of liquids and solids under extreme conditions are described. To illustrate the capability of this technique, results are given on the pressure and temperature dependence of acoustic properties for three prototypical cases: polycrystal (iron), single-crystal (silicon) and liquid (mercury) samples. It is shown that such technique also enables the determination of the density as a function of pressure for liquids, of the complete set of elastic constants for single crystals, and of the melting curve for any kind of material. High pressure ultrafast acoustic spectroscopy technique clearly opens opportunities to measure thermodynamical properties under previously unattainable extreme conditions. Beyond physics, this state-of-the-art experiment would thus be useful in many other fields such as nonlinear acoustics, oceanography, petrology, in of view. A brief description of new developments and future directions of works conclude the article. (C) 2014 Elsevier B.V. All rights reserved

Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature

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