Measurements of the thermal diffusivity of liquids with a thermal-wave resonator cavity

High precision measurements of Thermal Diffusivity of liquids, using a liqu id-compatible Thermal Wave Resonant Cavity (TWRC), are presented. The analy tical procedure involved linear fittings to the photothermal signal's ampli tude as function of the cavity length. The thermal-diffusivities of distill ed water, glycerol, olive oil and ethylene glycol were determined at room t emperature (25 degreesC), with four-significant-figure precision. The liqui d-state TWRC was applied to the measurements of Thermal Diffusivity of vari ous mixtures of methanol and salt in distilled water. The sensitivity limit s were found to be 0.5 % (v/v) and 0.03 % (w/v), respectively. The use of t he TWRC to measure gas evolution from liquids was explored by recording the sensor's signal amplitude for carbonated water as CO2 was evolving. The ob tained results show the TWRC potential for environmental applications.