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Proceedings Paper

Thermal fluctuation exponents for two near-critical point systems
Author(s): Ana Oprisan; Brittany Bayley; Sorinel A. Oprisan; John J. Hegseth; Yves Garrabos; Carole Lecoutre; Daniel Beysens
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Paper Abstract

In the supercritical phase, pure fluids have great potential for industrial applications and are increasingly used by industry as nonpolluting solvents of organic materials and media for high yield chemical reactions. The experimental data were recorded in microgravity for sulfur hexafluoride (SF6) and on Earth for density-matching binary mixture of methanol and partially deuterated cyclohexane (CC*-Me). We used small angle light scattering experiments to investigate fluctuations in SF6 near critical point and in density-matched binary mixture CC*-Me in the absence of convective flows. For binary mixture, we used three different filtering methods: bright filed (BF - no filter), phase contrast (PC - quarter wave plate at focal point) and dark field (DF - small opaque object at focal point). The power spectrum of scattered light contains information about local inhomogeneities encountered by light traveling through the sample cell unit (SCU). We found that the spatial correlations revealed by Fourier transforms follow power laws both for SF6 in microgravity and binary mixture on Earth. This is an indication of the universality of fluctuation mechanisms. Temporal correlations of fluctuations were investigated using the correlation time.

Paper Details

Date Published: 15 April 2010
PDF: 10 pages
Proc. SPIE 7701, Visual Information Processing XIX, 77010W (15 April 2010); doi: 10.1117/12.850557
Show Author Affiliations
Ana Oprisan, College of Charleston (United States)
Brittany Bayley, College of Charleston (United States)
Sorinel A. Oprisan, College of Charleston (United States)
John J. Hegseth, Univ. of New Orleans (United States)
Yves Garrabos, ESEME-CNRS, Institut de Chimie de la Matière Condensée de Bordeaux, Univ. Bordeaux (France)
Carole Lecoutre, ESEME-CNRS, Institut de Chimie de la Matière Condensée de Bordeaux, Univ. Bordeaux (France)
Daniel Beysens, ESEME-CEA-ESPCI, PMMH, CNRS, Univ. Paris 6 et Paris 7 (France)

Published in SPIE Proceedings Vol. 7701:
Visual Information Processing XIX
Zia-ur Rahman; Stephen E. Reichenbach; Mark A. Neifeld, Editor(s)

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