Measurement of Diffusion of Atmospheric Gases in a Liquid Perfluoro Compound by Means of an Optical Technique.

We report on accurate measurements of Fickian diffusion coefficients in binary mixtures consisting of hydrofluoroether (a perfluoro compound of methoxy-nonafluorobutane or HFE-7100) with dissolved atmospheric gases CO, N, and O in the limit of an infinite dilution of the gas. We show that the use of optical digital interferometry (ODI) allows the determination of diffusion coefficients of dissolved gases with relatively small standard uncertainties for this class of experiments. In addition, we illustrate the ability of an optical approach to determine the gas concentration.

Wall-generated pattern on a periodically excited miscible liquid/liquid interface.

We present a new generic type of pattern generated by bounding walls on the interface between miscible liquids in a horizontally vibrated cell. The pattern is observed in laboratory experiments and numerical simulations below and above the frozen-wave instability threshold. At the threshold, a competition develops between the new "fish-spine" pattern and frozen waves, while above the threshold these two kinds of patterns may coexist in spatially separated domains.