A recent approach taken to improve the efficiency of sonochemical processes and ultrasound reactors is to combine multiple transducers, operating at either the same or at different fundamental frequencies. This book investigates several different dual-frequency systems, looking at their potential advantages and limitations in ultrasonic processes, and the nature of the interaction between the different sound fields. This is ascertained through analysis of sonoluminescence and acoustic emissions, high-speed photographic imaging, cavitation bubble dynamics and interactions, and of the comparative reaction rates of selected sonochemical reactions. The influence of various parameters on the relative efficiency of the dual-frequency system is also examined. Additionally, this work sheds light on various peripheral, nevertheless highly important, issues such as the interactions between gas bubbles in the presence of electroyltes and other solutes.

Adam Brotchie obtained his PhD (2010)in physical chemistry from the University of Melbourne and is currently an Alexander von Humboldt fellow at the Max Planck Institute of Colloids and Interfaces, Potsdam, Germany. His main scientific interests concern the optimisation of sochemical systems and the sonochemical modification of interfaces.