INNOVATION IN NONCONTACT ULTRASONIC ANALYSIS - APPLICATIONS FOR HIDDEN OBJECTS DETECTION

This paper describes unusual applications of ultrasound that are based upon recent advances in transduction efficiency in air and gaseous me dia. Piezoelectric transducer devices - capable of generating extremel y high intensity ultrasound in ambient air up to 5 MHz - have been suc cessfully developed and tested. This is in addition to the obvious use s for gas analysis, remote sensing, liquid level, gap, and thickness m easurement, and proximity analysis. These new generation transducers m ake it possible to analyze solids and liquids not only non-destructive ly, but also without physically contacting the test sample. Among vari ous applications to the non-destructive characterization (NDC) of indu strial materials, we also describe the feasibility of a forensic appli cation. This concerns the detection of objects such as knives, guns, c ontraband drugs, dead bodies, etc., hidden inside false compartments o r walls.