The ultrasound is a its whose Fréquence is higher than 20.000 Hz.

The ultrasounds are mechanical waves, discovered in 1883 by the Physiologiste English Francis Galton. Not to forget a large French physicist Paul Langevin which invented the triplet of Langevin. The principle of this converter: two (or four or six) ceramic piezoelectric tight and put in prestressed between two metal masses to avoid their destruction. The two metal masses are also used to calibrate this acoustic whole at a preset frequency which can be usually included/understood between 20.000 Hz and 70.000 Hz. Under the excitation of a sinusoidal signal applied to ceramics (of a few hundreds of volts to a few thousands of volts), those become deformed while contracting. The agreement in frequency of the triplet or the acoustic unit (triplet of Langevin which can be called commonly converter or transmitter) is obtained when electricity consumption is minimal with a maximum displacement of the masses put moving. For that, the electric frequency of the signal applied to the triplet must be in agreement with its frequency of mechanical resonance. A simple example is that of a bell of church of several tons which can be put moving by only one man. This vibration thus created in ceramics is transmitted to the two metal masses. The amplitude of the displacement of the metal masses can be a few microns to more than 20 microns peak/peak. Displacement can be increased by adding a booster rocket (amplifying mechanics accelerating the wave propagation of vibration thus created) and a sonotrode, which is in fact the tool where this vibration will be used. The amplitude of displacement obtained can easily reach 100 microns, the electric output is exceptional, being able to reach 95 to 98%. Without this invention industry would not exploit this technology. Their behavior is due to their interactions with the medium where they are propagated.

The name comes owing to the fact that their frequency is too high to be audible for the man (the sound is too acute), in the same way that the Infrason S indicate the sounds whose frequency is too weak to be perceptible by the human ear.

However of many animals, such as for example the Dog S or the Bat, can hear these sounds. Some can emit some: the bats emit ultrasounds which are reflected on the surrounding objects, which thus enables them to perceive their environment (see echolocation ) . Like the Cetacea S, the Chiroptère S and some Rodent S, Amolops tormotus is a species of Chinese Grenouille able to emit and perceive ultrasounds, of more than 100 Khz. It is the only species not known Mammifère having this property. She lives close to the sources of warm water of Huangshan. The male pushes cries similar to a song of Oiseau and has a concave tympanum. However, recent work of a researcher seems to prove that certain caterpillars use their carapace to create ultrasounds thanks to percussions which they create on this one.

Applications

• in medicine, in particular the echography and the Thermotherapy by focused Ultrasounds;
• in laboratory (biology, chemistry, etc): the sonication is the use of ultrasounds to break the membranes of the cells, to clean or disinfect material.
• in agriculture by vibration of the water which is transformed into fog and feeds the system racinaire out of water and oxygen;
• in teledetection, for the Sonar;
• in Telemetry to measure the distances;
• in industry, for example for the non-destructive tests of materials, for the welding of thermoplastics, the welding of the non-ferrous metals (Copper/aluminum for example) cleaning by U.S one of all the first industrial application; in food cutting of cheeses, pastes, meats, fish, cakes at very high-speed and without any loss;
• for the activities of leisure, for example to create water sprays;
• to drive out animals considered harmful, the such rodents or the mosquitos, without using any toxic chemicals, for example with the generators Pest To drive out ;
• to drive out the young people of certain places;
• in telephony, like inaudible ringing, also called “ultrasonnery”, “ultra-ringing”, “ringing anti-old man” or “ringing anti-adult”, because the sounds of extremely high Fréquence S become inaudible for the adults as from approximately 25 years. It is called sometimes “teen buzz” or “ringing mosquito”, in reference to the Moustique S; It acts however in this case of a name of mercatic (marketing). By definition, the ultrasounds are inaudible for any human being;
• in auto industry, in order to avoid the obstacles. Thus, the system Park Assist of Volkswagen Touran makes it possible to be parked automatically in less than fifteen seconds: any parking bay parallel with the file of circulation available and measuring at least a meter forty of more than the vehicle, is recognized by the sensors with ultrasounds which make it possible to calculate the optimal trajectory to carry out the crenel without the driver not having to touch the wheel.
• In hairstyle for the capillary implants of extensions

Corrélats

• Echolocation (or echolocation )

Simple: Ultrasound