Ultragarsinis

Ultragarsinis is a Lithuanian adjective meaning ultrasonic. In scientific and engineering contexts, it describes phenomena, devices, and processes that operate at ultrasonic frequencies—mechanical waves with frequencies above the upper limit of human hearing.

Ultrasonic frequencies generally start above 20 kHz and extend into the megahertz (MHz) range. Applications are defined by the frequency and the energy of the wave; for example diagnostic medical ultrasound uses about 1–15 MHz, while industrial nondestructive testing often uses 0.5–20 MHz, and cleaning typically uses 20–40 kHz.

Key technologies involve transducers that convert electrical energy into mechanical oscillations. Most ultrasonics rely on piezoelectric materials, especially PZT crystals, though capacitive micromachined ultrasonic transducers (CMUTs) are also used. The waves propagate through liquids or solids and can produce effects such as cavitation (in liquids) or high-frequency vibration at surfaces.

Common applications include medical imaging (ultrasonography, Doppler), therapeutic ultrasound (high-intensity focused ultrasound or HIFU), nondestructive testing and flaw detection in metals and composites, ultrasonic cleaning, welding and machining, and sonar and underwater sensing.

Safety and regulation emphasize controlling acoustic output to minimize tissue heating and cavitation risks in medical use and to ensure reliable material inspection in industry. Standards issued by international bodies such as ISO and IEC guide equipment design, testing, and exposure limits.

Etymology: the term derives from ultra-, beyond, and sonic, related to sound. In many languages, including Lithuanian, ultragarsinis is used to denote ultrasonic.