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With special electronically driven crystals, it is possible to produce mechanical waves at any frequency up to a few million Hertz (cycles per second). If the sound waves are above 20kHz (the maximum humanly audible frequency) they are called ultrasonic waves. Because of their short wavelength, ultrasonic waves can be focused onto small areas and can be imaged much as visible light. Ultrasonic waves penetrate tissue and are scattered and absorbed within it. Using specialized techniques called ultrasound imaging, it is possible to form visible images of ultrasonic reflections and absorptions. Therefore, structures within living organisms can be examined with ultrasound, as with X-rays. Ultrasonic examinations are safer than X-rays and often can provide as much information. In some cases, such as in the examination of a fetus and the heart, ultrasonic methods can show motion, which is very useful in such displays.
Here are a few:
Ultrasonic motion detection
Here are a few:
Ultrasonic motion detection
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mostly to keep animals away.
CLEANING Cleaning was one of the earliest industrial applications of ultrasonics. Objects to be cleaned are placed in a bath of fluid which is violently agitated by a number… of ultrasonic transducers. The fluid may be water or solvent based, depending on the application. Traditionally the transducers were fitted around the walls of the cleaning bath, but some modern equipment uses an external transducer attached to a resonant probe which transmits the vibrations to the fluid. The ultrasonics may affect the cleaning process in several ways. Rapid movement in the fluid can help to de-wet surfaces, overcoming surface tension, and may also help to dislodge dirt particles and carry them away from the surface. Cavitation is probably the most interesting (and potent) effect - the shock waves generated by tiny implosions of vapour bubbles can be devastating at close range. The bubbles are so tiny that they can penetrate even the smallest crevices, making the process ideal for parts which could not be cleaned by other methods. Note also that the process must be well controlled to minimise erosion of the surfaces of the parts being cleaned. The standard test of ultrasonic intensity in a cleaning bath is to immerse a standard foil strip for a set time, then remove it and count the number of holes! CUTTING Imagine a knife which moves itself backwards and forwards in a sawing action, thirty thousand times a second. True the distance moved is very small but the acceleration is so high that nothing can move with the blade or stick to it. Ultrasonic scalpels are used by surgeons where they want to cut without exerting any pressure. In industry ultrasonic cutting tools are used for products that are difficult to cut by other means. The heat generated by the ultrasonic vibrations can also be useful. Some man-made fabrics are cut and simultaneously sealed using ultrasonic knives to prevent fraying. ULTRASONIC MACHINING Ultrasonics have been used in several ways for machining metals. Lathe tools may benefit from deliberately-induced vibrations to prevent "chatter" which compromises the surface finish of the finished component. Ultrasonic drills, used on very hard ceramics, work by grinding or eroding material away - a liquid slurry around the drill bit contains loose hard particles which are smashed into the surface by the vibrations, eroding material away and creating more loose hard particles METAL FORMING My own experience of power ultrasonics is mainly in this field. CarnaudMetalbox R&D (now a part of Crown Cork and Seal - the biggest packaging company in the world) and Loughborough University developed a new aerosol can using a number of novel metal-forming processes, starting with ultrasonic necking (i.e. reducing the diameter of the can at one end). The advantage of using ultrasonics in this case was to minimise friction between the can and the die, thus reducing the forming force. Without ultrasonics the force was so high that the can body would buckle and collapse during the necking process. With ultrasonics a 30% reduction in can diameter could be achieved in a single operation (in conventional necking processes the maximum is typically about 5%). The ultrasonics were only effective when the vibrations were perpendicular to the surface - for a cylindrical can this meant developing a round die that would vibrate in the radial direction. As with other high-power applications, all tooling had to be resonant, so the desired mode of resonance was a uniform hoop expansion / contraction. We quickly found that while it was fairly easy to design a die to resonate in this mode at the frequency of the ultrasonic equipment, excluding other modes of vibration was a major challenge! Another difficulty was that with the whole die expanding and contracting there was no convenient nodal (stationary) point which could be used for mouning it. This was solved by the use of a tubular mounting system which was itself resonant at the same frequency as the die. The ultrasonic forming process went into production making small-diameter aerosol cans in a UK factory. The production line still runs intermittently, making promotional packaging for several prominent customers. One of its products ("Fleurs de Paris" parfum deospray can) won a silver in the 1997 Metal Packaging Manufacturers Association awards. METAL WELDING . Ultrasonics can be used to weld different metals together, without solder and flux or special preparation. The process is different to plastic welding in that the two components are vibrated parallel to the interface. This is a more intuitively logical method of generating friction between them, but frictional heating is not thought to be the prime mechanism of the process - the temperature needed to melt (or even soften) most metals would be very difficult to achieve. Instead the mechanism is thought to be diffusion-bonding: atoms of each part diffuse into the other when the two surfaces are brought together in close contact. The ultrasonics promotes this close contact by breaking down the surface oxide layers, allowing the "raw" metals to make contact. The process has some limitations. It is only suitable for relatively small components (a prime example is welding connectors to car battery leads) since the power required to weld larger parts would be higher than can practically supplied by this method. Also the process tends to mark and deform the components, since high clamping forces and sonotrodes with serrated working faces must be used to grip the workpiece firmly. PLASTIC WELDING Plastic welding is used for a huge variety of products ranging from blister packs, cartons and small consumer goods up to car fuel tanks and dashboards. It works by generating heat exactly where it is needed - at the interface between the components to be joined. The components are clamped between a vibrating sonotrode and a fixed mounting. Strangely, the vibrations are usually applied perpendicular to the contact surface, although much of this vibration may be converted to in-plane movement. This also has the advantage that the clamping pressure will keep the sonotrode in contact with the component - serrated surfaces are generally not required. Best results are achieved when the components are clamped close to the interface ("near-field" welding) but if this is not possible then the process can still work at a distance ("far-field"). Staking, or insertion, is a variation of this process in which a metal part (generally a threaded bush) is driven into a hole in a plastic component, which then solidifies around it to form a permanent join. This is a convenient method of producing strong tapped holes in a plastic part. More information: SIEVING Industrial sieves are normally agitated at low frequency to help the product to distribute itself evenly over the surface and to help the small particles go through. Vibrating the mesh at ultrasonic frequencies (in addition to this low-frequency oscillation) can improve the rate of flow dramatically, preventing the product from blocking the holes in the mesh and helping to separate the small particles from the large. SINTERING The powder-metallurgy process is used to manufacture top-quality steels and other metals. The powder must be packed as closely as possible before the sintering process begins to prevent the formation of voids or other weaknesses in the finished product. Published research papers indicate that a significant increase in the packing density can be achieved using ultrasonics. Can anyone confirm that this process is in production?
The most common application of ultrasonic sound is in medical and other ultrasonic imaging.
Ultrasonic and Infrasonic sound waves are waves that are not audible to human beings. The audible region contains sound waves of 16 Hz to 20,000 Hz. Infrasonic sound waves ha…ve frequencies below 16 Hz. For example, an earthquake. Ultrasonic sound waves have frequencies above 20,000 Hz. For example, x-rays. Grade 11 Physics
Sound waves that are below or above the normal human range of hearing.
Ultrasonic cleaners are excellent for cleaning jewelry and most gems.
Ultrasonic sound waves travel at the same speed as lower frequency sound waves. The medium determines the speed at which a sound wave, which is mechanical energy, can travel. …Sound waves travel faster in liquids than in a gas (like air), and travel faster still in solids. The speed at which a sound wave travels is generally independent of the frequency of that sound. Use the link below for more information.
Sound waves- ultrasonic, sonic, or intrasonic are generally invisible. You cannot see sound.
Not exactly. Ultrasonic cleaners use ultrasound to produce a phenomenon known as cavitation. The ultrasonic wave fronts produce microscopic vacuum bubbles that are forced agai…nst, and collapse upon the surface being cleaned. When these bubbles collapse, water and cleaning solution is shot into the space they once occupied, thus creating a cleaning action.
yes u s used in ttt of arthriris to relive pain
Yes indeed, it is therefore distinguished from Radar which uses radio-wave emissions, hence Radio Detection( or direction) and ranging. Sonar is used on ships- though some Bli…mps used it in sonic rangefinders used in pin-pointing altitude and also to detect submarines. The German made device was called an Echolot ( Echo- Location plot) by the Germans and Sonicaltimeter by the USN boys. The idea was championed by Admiral Rosenthal, who saw it as an easy transition to use of Blimps in an anti-sub role. the British referred to SONAR as Asdic- Anti-Submarine Detection improvement committee, who developed the device. Porpoises, some whales, and it is understood seals ( Pinnipeds, not commandos!) use naturally existent Sonar, as Bats employ radar.
no Because ultrasonic sound waves are not audible and it is not possible to create that much loudness in normal speakers.
They have a frequency of above 20,000Hz inaudible to human ear.
Ultrasonic means 'faster than sound'. This means no sound wave can be faster than sound.
The sound waves which are below the audible sound are called infrasonics(<20Hz) and The sound waves which are above the audible sound are called ultrasonics(>20KHz).