This paper describes some recent advances in the use of electrostatic
transducers for performing ultrasonic measurements in both air and wat
er. It will be shown that through-transmission imaging can be performe
d in metals, polymers and fibre-reinforced composites. Also possible a
re various forms of imaging in air, including tomographic reconstructi
on of flow and temperature fields in gases. (C) 1998 Elsevier Science
B.V.