Acoustic attenuation and velocity measurements in a methanol and cyclohexane critical mixture

Abstract

Acoustic attenuation and velocity measurements by an improved pulse-echo technique have been made in the critical region of methanol and cyclohexane critical mixture at its critical composition. The measurements have been performed in the frequency range 5-45 MHz and in the temperature range 34.3-57.9 degrees C. Large acoustic attenuation was observed in the entire temperature range. Fixman's theory (1962) of critical sound attenuation explains the experimental results reasonably well. The Debye short-range correlation lengths for this system are found to be 9.9*10-8 cm (above Tc) and 10.3*10-8 cm (below Tc).