Attenuation of Ultrasonic Waves in Aqueous Emulsions of iso-Octane

The attenuation of ultrasonic waves at 3MHz in aqueous emulsions of iso-octane is measured in the range of average particle radius of 2 to 16 microns. Observed values agree well with those calculated from theory, including scattering loss, viscous drag loss, and loss due to thermal conduction between particle and medium, the last of which has been predicted by Isakovich. In the present case in which the particle radius is much smaller than the incident wavelength and much greater than viscous wavelength, the thermal conduction loss plays a dominant role.