This is tangential, but as a medical device engineer and one that works quite a bit with Ultrasound, the title of this article caught my interest, but it turned out to be about something completely different.<p><a href="http://en.wikipedia.org/wiki/Ultrasonic_sensor#Transducers" rel="nofollow">http://en.wikipedia.org/wiki/Ultrasonic_sensor#Transducers</a>