Sound waves are mechanical vibrations that travel through solids in the form of transverse waves, and through liquids and gases in the form of longitudinal waves. Ultrasound refers to sound waves having a frequency higher than the range audible to humans. The lowest ultrasonic frequency is commonly taken as 20 kHz (1 Hertz 1 cycle per second). The upper limit of ultrasound frequencies is not clearly defined but is usually taken to be 5 MHz for gases and 500 MHz for liquids and solids (1). Applications of ultrasound can be divided broadly into two categories: lowand high-power ultrasound (Figure 121.1).
|Original language||English (US)|
|Title of host publication||Handbook of Food Science, Technology, and Engineering - 4 Volume Set|
|Number of pages||9|
|State||Published - Jan 1 2005|
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)