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An ultrasonic examination. Ultrasound is sound with frequencies greater than 20 kilohertz. [1] This frequency is the approximate upper audible limit of human hearing in healthy young adults. The physical principles of acoustic waves apply to any frequency range, including ultrasound.
Buzz pollination, or sonication, serves as an example of a behavioral response to specific frequencies of vibrations in plants.Some 20000 plants species, [7] including Dodecatheon and Heliamphora have evolved buzz pollination in which they release pollen from anthers only when vibrated at a certain frequency created exclusively by bee flight muscles.
Sound waves propagating through a liquid at ultrasonic frequencies have wavelengths many times longer than the molecular dimensions or the bond length between atoms in the molecule. Therefore, the sound wave cannot directly affect the vibrational energy of the bond, and can therefore not directly increase the internal energy of a molecule.
The term echolocation was coined by 1944 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. [1] [2] As Griffin described in his book, [3] the 18th century Italian scientist Lazzaro Spallanzani had, by means of a series of elaborate experiments, concluded that when bats fly at night, they rely on some sense besides vision, but he did ...
Sonication can be used for the production of nanoparticles, such as nanoemulsions, [5] nanocrystals, liposomes and wax emulsions, as well as for wastewater purification, degassing, extraction of seaweed polysaccharides [1] and plant oil, extraction of anthocyanins and antioxidants, [6] production of biofuels, crude oil desulphurization, cell disruption, polymer and epoxy processing, adhesive ...
This equation says that the audible demodulated ultrasonic pressure wave (output signal) is proportional to the twice differentiated, squared version of the envelope function (input signal). Precompensation refers to the trick of anticipating these transforms and applying the inverse transforms on the input, hoping that the output is then ...
An ultrasonic transducer is affixed to a stainless steel pan which is filled with a solvent (frequently water or isopropanol). An electrical square wave feeds the transducer, creating sound in the solvent strong enough to cause cavitation. Ultrasonic technology has been used for multiple cleaning purposes.
Ultrasonic algae control is a commercial technology that has been claimed to control the blooming of cyanobacteria, algae, and biofouling in lakes, and reservoirs, by using pulsed ultrasound. [ 6 ] [ 7 ] The duration of such treatment is supposed to take up to several months, depending on the water volume and algae species.