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Mechanism Of Sonoluminescence
Sonoluminescence is a phenomenon that occurs when a small gas bubble is acoustically suspended and periodically driven in a liquid solution at ultrasonic frequencies, resulting in bubble collapse, cavitation, and light emission. The thermal energy that is released from the bubble collapse is so great that it can cause weak light emission. The mechanism of the light emission remains uncertain, but some of the current theories, which are categorized under either thermal or electrical processes, are Bremsstrahlung radiation, argon rectification hypothesis, and hot spot. Some researchers are beginning to favor thermal process explanations as temperature differences have consistently been observed with different methods of spectral analysis. In order to understand the light emission mechanism, it is important to know what is happening in the bubble's interior and at the bubble's surface. Current competing theories Prior to the early 1990s, the studies on different chemical and physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonoluminescence
Sonoluminescence is the emission of light from imploding bubbles in a liquid when excited by sound. History The sonoluminescence effect was first discovered at the University of Cologne in 1934 as a result of work on sonar. Hermann Frenzel and H. Schultes put an ultrasound transducer in a tank of photographic developer fluid. They hoped to speed up the development process. Instead, they noticed tiny dots on the film after developing and realized that the bubbles in the fluid were emitting light with the ultrasound turned on. It was too difficult to analyze the effect in early experiments because of the complex environment of a large number of short-lived bubbles. This phenomenon is now referred to as multi-bubble sonoluminescence (MBSL). In 1960, Peter Jarman from Imperial College of London proposed the most reliable theory of sonoluminescence phenomenon. He concluded that sonoluminescence is basically thermal in origin and that it might possibly arise from microshocks with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh–Plesset Equation
In fluid mechanics, the Rayleigh–Plesset equation or Besant–Rayleigh–Plesset equation is an ordinary differential equation which governs the Dynamics (mechanics), dynamics of a spherical liquid bubble, bubble in an infinite body of incompressible fluid. Its general form is usually written as : R\frac + \frac\left(\frac\right)^2 + \frac\frac + \frac + \frac =0 where :\rho_L is the density of the surrounding liquid, assumed to be constant :R(t) is the radius of the bubble :\nu_L is the kinematic viscosity of the surrounding liquid, assumed to be constant :\gamma is the surface tension of the bubble-liquid interface :\Delta P(t) = P_\infty(t) - P_B(t), in which, P_B(t) is the pressure within the bubble, assumed to be uniform and P_\infty(t) is the external pressure infinitely far from the bubble Provided that P_B(t) is known and P_\infty(t) is given, the Rayleigh–Plesset equation can be used to solve for the time-varying bubble radius R(t). The Rayleigh–Plesset equatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Spot Diagram
Hot or the acronym HOT may refer to: Food and drink * Pungency, in food, a spicy or hot quality *Hot, a wine tasting descriptor Places * Hot district, a district of Chiang Mai province, Thailand **Hot subdistrict, a sub-district of Hot District, Thailand **Tha Kham, Chiang Mai, also known as Hot, a town in Hot District, Chiang Mai province, Thailand *Hot, Albania, a village in the Malësi e Madhe municipality, Shkodër County, Albania Music *H.O.T. pronounced "H. O. T.", (High-Five of Teenagers), a South Korean boy band * Hawaii Opera Theatre, an opera company in Honolulu, Hawaii *Hot (American vocal group), best known for 1977 hit "Angel in Your Arms" 1976–1980 *Hot 97, branding for hip-hop radio station WQHT in New York City Albums * ''Hot'' (Freda Payne album), 1979 * ''Hot'' (Half Japanese album), 1995 * ''Hot'' (Inna album) or the title song (see below), 2009 * ''Hot'' (James Brown album) or the title song (see below), 1976 * ''Hot'' (Mel B album), 2000 * ''Hot'' (Pau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kenneth S
Kenneth is an English given name and surname. The name is an Anglicised form of two entirely different Gaelic personal names: ''Cainnech'' and '' Cináed''. The modern Gaelic form of ''Cainnech'' is ''Coinneach''; the name was derived from a byname meaning "handsome", "comely". A short form of ''Kenneth'' is '' Ken''. Etymology The second part of the name ''Cinaed'' is derived either from the Celtic ''*aidhu'', meaning "fire", or else Brittonic ''jʉ:ð'' meaning "lord". People :''(see also Ken (name) and Kenny)'' Places In the United States: * Kenneth, Indiana * Kenneth, Minnesota * Kenneth City, Florida In Scotland: * Inch Kenneth, an island off the west coast of the Isle of Mull Other * "What's the Frequency, Kenneth?", a song by R.E.M. * Hurricane Kenneth * Cyclone Kenneth Intense Tropical Cyclone Kenneth was the strongest tropical cyclone to make landfall in Mozambique since modern records began. The cyclone also caused significant damage in the Comoro Islands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionization Energy
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules and ions, or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can result in the formation of ion pairs. Ionization can occur through radioactive decay by the internal conversion process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected. Uses Everyday examples of gas ionization are such as within a fluorescent lamp or other electrical discharge lamps. It is also used in radiation detectors such as the Geiger-Müller counter or the ionization chamber. The ionizati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bremsstrahlung
''Bremsstrahlung'' (), from "to brake" and "radiation"; i.e., "braking radiation" or "deceleration radiation", is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into radiation (i.e., photons), thus satisfying the law of conservation of energy. The term is also used to refer to the process of producing the radiation. ''Bremsstrahlung'' has a continuous spectrum, which becomes more intense and whose peak intensity shifts toward higher frequencies as the change of the energy of the decelerated particles increases. Broadly speaking, ''bremsstrahlung'' or braking radiation is any radiation produced due to the deceleration (negative acceleration) of a charged particle, which includes synchrotron radiation (i.e., photon emission by a relativistic particle), cyclotron radiation (i.e. photon emission by a non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoric Acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, which is a colourless, odourless, and non- volatile syrupy liquid. It is a major industrial chemical, being a component of many fertilizers. The compound is an acid. Removal of all three ions gives the phosphate ion . Removal of one or two protons gives dihydrogen phosphate ion , and the hydrogen phosphate ion , respectively. Phosphoric acid forms esters, called organophosphates. The name "orthophosphoric acid" can be used to distinguish this specific acid from other "phosphoric acids", such as pyrophosphoric acid. Nevertheless, the term "phosphoric acid" often means this specific compound; and that is the current IUPAC nomenclature. Production Phosphoric acid is produced industrially by one of two routes, wet processes and dry. We ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere The greatest commercial use of the element is the production ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Pressure Vs Bubble Radius
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) * A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid. For this reason, an object whose average density is greater than that of the fluid in which it is submerged tends to sink. If the object is less dense than the liquid, the force can keep the object afloat. This can occur only in a no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bjerknes Force
Bjerknes forces are translational forces on bubbles in a sound wave. The phenomenon is a type of acoustic radiation force. ''Primary'' Bjerknes forces are caused by an external sound field; ''secondary'' Bjerknes forces are between pairs of bubbles in the same sound field. They were first described by Vilhelm Bjerknes in his 1906 ''Fields of Force''. Theory The force on a small particle in a sound wave is given by: : F = - V \nabla P where V is the volume of the particle, and \nablaP is the acoustic pressure gradient on the bubble. Assuming a sinusoidal travelling wave, the time-averaged pressure gradient over a single acoustic cycle is zero, meaning a solid particle (with fixed volume) experiences no net force. However, because a bubble is compressible, the oscillating pressure field also causes its volume to change; for spherical bubbles this can be described by the Rayleigh-Plesset equation. This means the time-averaged product of the bubble volume and the pressure grad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
