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Acoustic Levitation
Acoustic levitation is a method for suspending matter in air against gravity using acoustic radiation pressure from high intensity sound waves. It works on the same principles as acoustic tweezers by harnessing acoustic radiation forces. However acoustic tweezers are generally small scale devices which operate in a fluid medium and are less affected by gravity, whereas acoustic levitation is primarily concerned with overcoming gravity. Technically dynamic acoustic levitation is a form of acoustophoresis, though this term is more commonly associated with small scale acoustic tweezers. Typically sound waves at ultrasonic frequencies are used thus creating no sound audible to humans. This is primarily due to the high intensity of sound required to counteract gravity. However, there have been cases of audible frequencies being used. There are various techniques for generating the sound, but the most common is the use of piezoelectric transducers which can efficiently generate high am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Radiation Pressure
Acoustic radiation pressure is the apparent pressure difference between the average pressure at a surface moving with the displacement of the wave propagation (the Lagrangian pressure) and the pressure that would have existed in the fluid of the same mean density when at rest. Numerous authors make a distinction between the phenomena of Rayleigh radiation pressure and Langevin radiation pressure. See also * Radiation pressure * Acoustic levitation Acoustic levitation is a method for suspending matter in air against gravity using acoustic radiation pressure from high intensity sound waves. It works on the same principles as acoustic tweezers by harnessing acoustic radiation forces. However ... * Acoustic radiation force References * * * * External links Tokyo University Researchers Using Ultrasound Technology to Enable Touchable Holograms Acoustics {{acoustics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC Earth
BBC Earth is a brand used by BBC Studios since 2009 to market and distribute the BBC's natural history content to countries other than the United Kingdom. BBC Studios is the commercial arm of the public service broadcaster. BBC Earth commercially represents the BBC Natural History Unit, the largest wildlife documentary production house in the world. It is part of British Broadcasting Corporation. BBC Earth is responsible for the worldwide marketing and distribution of titles such as ''Planet Earth'', ''Frozen Planet'', '' Life'', ''The Blue Planet'', and ''Planet Earth II''. It has generated sales to over 180 countries. The BBC Earth brand is used across a range of media platforms, including concert-style documentary viewings with a live orchestra and interactive experiences at museums and theme parks. Its website was relaunched in 2010 incorporating a new consumer-facing site "Life Is" which features a bi-monthly magazine style update and a blog. The brand is also used for new ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Bristol
, mottoeng = earningpromotes one's innate power (from Horace, ''Ode 4.4'') , established = 1595 – Merchant Venturers School1876 – University College, Bristol1909 – received royal charter , type = Public red brick research university , endowment = £91.3 million (2021) , budget = £752.0 million (2020–21) , chancellor = Paul Nurse , vice_chancellor = Professor Evelyn Welch , head_label = Visitor , head = Rt Hon. Penny Mordaunt MP , academic_staff = 3,385 (2020) , students = () , undergrad = () , postgrad = () , city = Bristol , country = England , coor = , campus = Urban , free_label = Students' Union , free = University of Bristol Union , colours ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Virtual Vortices Levitating Mie Particle
Acoustic may refer to: Music Albums * ''Acoustic'' (Above & Beyond album), 2014 * ''Acoustic'' (Deine Lakaien album), 2007 * ''Acoustic'' (Everything but the Girl album), 1992 * ''Acoustic'' (John Lennon album), 2004 * ''Acoustic'' (Love Amongst Ruin album), 2011 * ''Acoustic'' (Nitty Gritty Dirt Band album), 1994 * ''Acoustic'' (Nouvelle Vague album), 2009 * ''Acoustic'' (Simple Minds album), 2016 * '' The Acoustic'', by Ektomorf, 2012 * ''Acoustic'', by Oumou Sangaré, 2020 EPs and singles * ''Acoustic'' (Bayside EP), 2006 * ''Acoustic'' (Britt Nicole EP), 2010 * ''Acoustic'' (Coldplay EP), 2000 * ''Acoustic'' (Lights EP), 2010 * ''Acoustic'' (Second Coming EP), an acoustic version of ''13'', 2003 * ''Acoustic'', by Brandi Carlile, 2004 * ''Acoustic'', by Gabrielle Aplin, 2010 * ''Acoustic'', by Press to Meco, 2019 * "Acoustic" (single), "Follow You Home" and "Refugees", by Embrace, 2014 Companies * ''Acoustic'' (magazine) * ''Acoustic Guitar'' (magazine) * Aco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boundary Element Method
The boundary element method (BEM) is a numerical computational method of solving linear partial differential equations which have been formulated as integral equations (i.e. in ''boundary integral'' form), including fluid mechanics, acoustics, electromagnetics (where the technique is known as method of moments or abbreviated as MoM), fracture mechanics, and contact mechanics. Mathematical basis The integral equation may be regarded as an exact solution of the governing partial differential equation. The boundary element method attempts to use the given boundary conditions to fit boundary values into the integral equation, rather than values throughout the space defined by a partial differential equation. Once this is done, in the post-processing stage, the integral equation can then be used again to calculate numerically the solution directly at any desired point in the interior of the solution domain. BEM is applicable to problems for which Green's functions can be calculated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite Element Method
The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat transfer, fluid flow, mass transport, and electromagnetic potential. The FEM is a general numerical method for solving partial differential equations in two or three space variables (i.e., some boundary value problems). To solve a problem, the FEM subdivides a large system into smaller, simpler parts that are called finite elements. This is achieved by a particular space discretization in the space dimensions, which is implemented by the construction of a mesh of the object: the numerical domain for the solution, which has a finite number of points. The finite element method formulation of a boundary value problem finally results in a system of algebraic equations. The method approximates the unknown function over the domain. The simpl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John William Strutt, 3rd Baron Rayleigh
John William Strutt, 3rd Baron Rayleigh, (; 12 November 1842 – 30 June 1919) was an English mathematician and physicist who made extensive contributions to science. He spent all of his academic career at the University of Cambridge. Among many honors, he received the 1904 Nobel Prize in Physics "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies." He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919. Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue. He studied and described transverse surface waves in solids, now known as "Rayleigh waves". He contributed extensively to fluid dynamics, with concepts such as the Rayleigh number (a dimens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tractor Beam
A tractor-beam is a device with the ability to attract one object to another from a distance. The concept originates in fiction: The term was coined by E. E. Smith (an update of his earlier "attractor-beam") in his novel '' Spacehounds of IPC'' (1931). Since the 1990s, technology and research has labored to make it a reality, and have had some success on a microscopic level. Less commonly, a similar beam that repels is called a pressor beam or repulsor-beam. Gravity impulse and gravity propulsion beams are traditionally areas of research from fringe physics that coincide with the concepts of tractor and repulsor-beams. Physics A force field confined to a collimated beam with clean borders is one of the principal characteristics of tractor and repulsor beams. Several theories that have predicted repulsive effects do not fall within the category of tractor and repulsor beams because of the absence of field collimation. For example, Robert L. Forward, Hughes Research Laboratories, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Ultrasound
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g. distances and velocities) or to generate an informative audible sound. Its aim is usually to find a source of disease or to exclude pathology. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. Ultrasound is composed of sound waves with frequencies which are significantly higher than the range of human hearing (>20,000 Hz). Ultrasonic images, also known as sonograms, are created by sending pulses of ultrasound into tissue usi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Testing
Ultrasonic testing (UT) is a family of non-destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. In most common UT applications, very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz, and occasionally up to 50 MHz, are transmitted into materials to detect internal flaws or to characterize materials. A common example is ultrasonic thickness measurement, which tests the thickness of the test object, for example, to monitor pipework corrosion. Ultrasonic testing is often performed on steel and other metals and alloys, though it can also be used on concrete, wood and composites, albeit with less resolution. It is used in many industries including steel and aluminium construction, metallurgy, manufacturing, aerospace, automotive and other transportation sectors. History The first efforts to use ultrasonic testing to detect flaws in solid material occurred in the 1930s.''Nondestructive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase (waves)
In physics and mathematics, the phase of a periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is denoted \phi(t) and expressed in such a scale that it varies by one full turn as the variable t goes through each period (and F(t) goes through each complete cycle). It may be measured in any angular unit such as degrees or radians, thus increasing by 360° or 2\pi as the variable t completes a full period. This convention is especially appropriate for a sinusoidal function, since its value at any argument t then can be expressed as \phi(t), the sine of the phase, multiplied by some factor (the amplitude of the sinusoid). (The cosine may be used instead of sine, depending on where one considers each period to start.) Usually, whole turns are ignored when expressing the phase; so that \phi(t) is also a periodic function, with the same period as F, that repeatedly scans the same range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
