INVESTIGATIONS OF ICE NUCLEATION IN WATER-IN-OIL EMULSIONS USING ULTRASOUND VELOCITY-MEASUREMENTS

Ultrasound velocity measurements were used to monitor the nucleation o f ice in aqueous emulsions. Pure water emulsions or water emulsions in seminated with ice nucleating particles were cooled and the velocity o f an ultrasound wave passing through the sample recorded as a function of temperature. The proportion of ice was determined from the ultraso und velocity measurement. The results demonstrate the utility of ultra sound velocity measurements in monitoring ice nucleation in aqueous em ulsions. Stirring the sample makes a significant difference to the ice nucleation rate.