Industrial Applications of Ultrasound - A Review II. Measurements, Tests, and Process Control Using Low-Intensity Ultrasound

position, phase, thickness, composition, anisotropy and texture, grain size, stress and strain, elastic properties, bubble, particle and leak detection, nondestructive testing, acoustic emission, imaging and holography, and combinations of these. Principles, techniques, equipment, and application data are summarized for these areas. Most of the measurements utilize approaches designed to respond primarily to sound speed, but some depend on attenuation effects. Most equip- ment in use involves intrusive probes, but noninvasive, externally- mounted transducers are being promoted in several areas. Both pulse and resonance techniques are widely used. Limitations due to the influence of unwanted variables are identified in some cases. A bibliography and list of vendors provide sources for further information.