ultrason

Ultrason, typically referred to as ultrasonics or ultrasound, denotes sound waves with frequencies above the upper limit of human hearing, usually above 20 kilohertz. The term can describe both the acoustic waves themselves and devices that emit and detect them. In practice, ultrasonics spans a wide range of frequencies and media, from air to water and biological tissues.

Ultrasonic waves are generated mainly by piezoelectric transducers or magnetostrictive actuators that convert electrical energy into mechanical vibration. They propagate differently in materials; speed is determined by the medium, frequency, and temperature. Attenuation increases with frequency, influencing resolution and penetration depth. Coupling media such as gels or water are used to bridge air gaps in imaging or testing.

Medical ultrasound uses high-frequency, focused waves to create images of internal structures; modalities include B-mode imaging, Doppler for blood flow, and therapeutic uses like high-intensity focused ultrasound (HIFU) for tissue ablation. Safety relies on controlling exposure and mechanical and thermal index.

In nondestructive testing, ultrasound probes inspect welds, composites, and metals; techniques include pulse-echo, through-transmission, and phased-array methods. Ultrasonic cleaning uses cavitation in liquids to remove contaminants. Ultrasonics also supports sonochemistry, welding, machining, and material processing.

Sonar and underwater navigation rely on ultrasonic waves. Ultrasonics is also used for sensing distance, level measurement, and flow detection in industrial automation.