An NDE technique which relies on an ultrasonic beam passing through a coating and substrate and providing a signal from the back wall which is then detected. The height of this backwall echo depends on the discontinuity in impedance from the sprayed coating to the substrate. Bonding flaws can be easily seen by the weakening of the back wall echo.
... Found on http://www.poeton.co.uk/w1/glossary.htm
Sound at frequencies above the audible range, i.e. above about 20 kHz.Biological effects of ultrasound:Thermal â€` tissue is damaged due to heatingNonthermal â€` tissue damage due to mechanisms other than heating. These include mechanical forces on or within the tissue.Cavitational mechanisms â€` microstreaming, shock waves and microjetsNo... Found on http://www.diracdelta.co.uk/science/source/u/l/ultrasonic/source.html