Abstract
We have measured the shear viscosity of ternary mixtures of 3-methylpyridine, water (H2O), and heavy water (D2O) as a function of temperature for ten different concentrations, some of which were very near the double-critical-point concentration of this mixture. The exponent to describe the power-law divergence in temperature of the viscosity nearly doubles as the concentration approaches the double-critical-point concentration.