ultrasonic

Many pedagogical and scientific sources suggest that the highest pitches reached in classical singing can only be produced with a so-called "whistle" voice register, in analogy to ultrasonic vocalizations of mice and rats.

Lighting a gas grill, getting an ultrasound, using an ultrasonic toothbrush -- these actions involve the use of materials that can translate an electric voltage into a change in shape and vice versa.

When they hear a bat nearby, they respond with their own ultrasonic signal, and for the past 30 years, no one has known why.

The key breakthrough is the use of ultrasonic array sensors, which are essentially the same as those used in medical imaging in, for example, creating images of babies in the womb.

The Drexel team's approach is based on monitoring ultrasonic stress wave propagation, a technique frequently used for checking the structural health of pipelines, railroads and aircraft wings.