ABSTRACT
High-intensity applications of ultrasonics are those that produce changes in or effects on the media, or the contents of the media, through which the waves propagate. Various mechanisms may be activated by the ultrasonic energy to promote the effects, but the mechanisms involved are not always well known or understood. High-intensity ultrasonic energy has produced many very interesting effects in the laboratory. Ultrasonic homogenizers have been available commercially for many years and are extensively used as laboratory devices, most often used for sample preparation requiring dispersing and lysis of biological cells and tissues. Developing ultrasonic methods into practical applications is a multifaceted process. Ultrasonic energy is also a means of producing “deep heat” for medical therapy and in near-surface surgery. High-power ultrasonic fields can vary significantly in terms of their three-dimensional form, temporal geometry, and space–time evolution. Ultrasonic cavitation is the formation of bubbles or cavities in liquids during the low-pressure portion of a pressure wave cycle.
