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The process of creating three dimensional objects from digital data using a materials printer, in a manner similar to printing images on paper. The term is most closely associated with additive manufacturing technology, where an object is created by laying down successive layers of material.
The removal of material from the surface of an object by vaporisation, chipping, or other erosive processes. The term occurs in space physics associated with atmospheric reentry, in glaciology, medicine and passive fire protection. In space vehicle design, ablation is used to both cool and protect mechanical parts and/or payloads that would otherwise be adversely affected by extremely high temperatures.
The process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive.
The process by which the energy of a photon is taken up by matter, typically the electrons of an atom. The electromagnetic energy is transformed to another form of energy, e.g. to heat.
A physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase – gas, liquid or solid material. This is a different from Adsorption, since the molecules are taken up by the volume, not by surface.
Spectroscopic techniques that measure the absorption of radiation as a function of frequency or wavelength, due to its interaction with a sample.
A filter that absorbes some wavelengths of incident radiation whilst transmitting others.
A device for measuring acceleration and gravity induced reaction forces.
An apparatus by means of which energy can be stored, such as a rechargeable battery or a hydraulic accumulator. May be electrical, fluidic or mechanical. Sometimes used to convert a small continuous power source into a short surge of energy or vice versa. Other examples include capacitors, compulsators, steam accumulator, wave energy machines and pumped-storage hydroelectric plants.
The process by which a material, structure, or object takes in sound energy when sound waves are encountered, as opposed to reflecting the energy. Part of the absorbed energy is transformed into heat and part is transmitted through the absorbing body.
Cavitation induced by an acoustic field. Microscopic gas bubbles which are generally present in a liquid will be forced to oscillate due to an applied acoustic field. If the acoustic intensity is sufficiently high, the bubbles will first grow in size, and then rapidly collapse. High power ultrasonics usually use the inertial cavitation of microscopic vacuum bubbles for treatment of surfaces, liquids and slurries.
Transient elastic waves within a material due to localised stress release. Acoustic Emission (AE) events can occur rapidly when materials begin to fail. AE events commonly studied include the extension of a fatigue crack, or fibre breakage in composite materials. AE is related to an irreversible release of energy, and can be generated from sources not involving material failure including friction, cavitation and impact.
A mechanical device used in loudspeaker design, ultrasound imaging and other applictions to direct and modify sound waves in a manner analogous to optical lenses.
A method for suspending matter in a medium by using acoustic radiation pressure from intense sound waves in the medium. Usually used for containerless processing. Although harder to control than some other methods it has the advantage of being able to levitate nonconducting materials.
(or sonic lubrication) occurs when sound permits vibration to introduce separation between sliding faces (or between a series of particles). The frequency of sound required to induce optimal vibration, and thus cause sonic lubrication, varies with the size of the particles (high frequencies will have the effect on sand and lower frequencies will have on boulders).
In the case of a compacted divided solid.
A microscopy technique that employs very high or ultra high frequency ultrasound. Acoustic microscopes operate non-destructively and penetrate most solid materials to make visible images of internal features, including defects such as cracks, delaminations and voids.
A force on a particle suspended in the field of a sound wave arising from the scattering of the acoustic waves on the particle.
A technology for controlling the movement of objects by sound waves. In a standing acoustic field, objects will experience an acoustic radiation force that moves the objects to special regions of the acoustic field.Depending on the properties of the objects, they can be moved to either acoustic pressure nodes or pressure antinodes.
The the use of structures or other systems to affect the generation, propagation and reception of mechanical waves and vibrations.
For example, the use of sound-absorbing materials.
A specific case of photoelasticity, where there is a change of a material’s permittivity due to a mechanical strain resulting from an acoustic wave which has been excited within a transparent medium giving rise to variation of the refractive index. This creates a diffraction grating moving with the velocity given by the spread on the sound wave in the medium which defracts light forming a prominent diffraction pattern.
Through Bragg cell deflection into an absorbent region
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