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Luminous Flame
A luminous flame is a burning flame which is brightly visible. Much of its output is in the form of visible light, as well as heat or light in the non-visible wavelengths. An early study of flame luminosity was conducted by Michael Faraday and became part of his series of Royal Institution Christmas Lectures, ''The Chemical History of a Candle''. Luminosity In the simplest case, the yellow flame is luminosity, luminous due to small soot particles in the flame which are heated to incandescence. Producing a deliberately luminous flame requires either a shortage of combustion air (as in a Bunsen burner) or a local excess of fuel (as for a kerosene torch). Because of this dependency upon relatively inefficient combustion, luminosity is associated with diffusion flames and is lessened with premixed flames. The flame is yellow because of its temperature. To produce enough soot to be luminous, the flame is operated at a lower temperature than its efficient heating flame (see #Bunsen b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premixed Flame
A premixed flame is a flame formed under certain conditions during the combustion of a premixed charge (also called pre-mixture) of fuel and oxidiser. Since the fuel and oxidiser—the key chemical reactants of combustion—are available throughout a homogeneous stoichiometric premixed charge, the combustion process once initiated sustains itself by way of its own heat release. The majority of the chemical transformation in such a combustion process occurs primarily in a thin interfacial region which separates the unburned and the burned gases. The premixed flame interface propagates through the mixture until the entire charge is depleted. The propagation speed of a premixed flame is known as the flame speed (or burning velocity) which depends on the convection-diffusion-reaction balance within the flame, i.e. on its inner chemical structure. The premixed flame is characterised as laminar or turbulent depending on the velocity distribution in the unburned pre-mixture (which provides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion Engineering
Combustion Engineering (C-E) was a multi-national American-based engineering firm that developed nuclear steam supply power systems in the United States. Originally headquartered in New York City, C-E moved its corporate offices to Stamford, Connecticut in 1973. C-E owned over three dozen other companies including Lummus Company, National Tank Company and the Morgan Door Company. The company was acquired by Asea Brown Boveri in early 1990. The boiler and fossil fuel businesses were purchased by Alstom in 2000, and the nuclear business was purchased by Westinghouse Electric Company also in 2000. History Founding Combustion Engineering was organized in 1912 through the merger of the Grieve Grate Company and the American Stoker Company, two well-known manufacturers of fuel burning equipment. The company was originally headquartered on 11 Broadway and at 43 ''-'' 5 ''-'' 7 Broad Street (Manhattan), both in Lower Manhattan. The city block was leased from the Alliance Realty Compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flame Test
A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride ion). The color of flames in general also depends on temperature and oxygen fed; see flame color. Process The test involves introducing a sample of the element or compound to a hot, non-luminous flame, and observing the color of the flame that results. The idea of the test is that sample atoms evaporate and since they are hot, they emit light when being in flame. The solvent of the solution evaporates first, leaving finely divided solid particles which move to the hottest region of the flame where gaseous atoms and ions are produced through the dissociation of molecules. Here electrons are excited by the heat, and the spontaneously emit photon to decay to lower energy states. Bulk sample emits light too, but its light is not good for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same frequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rare-earth Element
The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides (yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare earths have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes. Scandium and yttrium are considered rare-earth elements because they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties, but have different electronic and magnetic properties. These metals tarnish slowly in air at room temperature and react slowly with cold water to form hydroxides, liberating hydrogen. They react with steam to form oxides, and at elevated temperature (400°C) ignite spontaneously. These elements and their compounds have no biological function other than in several specialized enzymes, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Mantle
A Coleman white gas lantern mantle glowing at full brightness An incandescent gas mantle, gas mantle or Welsbach mantle is a device for generating incandescent bright white light when heated by a flame. The name refers to its original heat source in gas lights which illuminated the streets of Europe and North America in the late 19th century. ''Mantle'' refers to the way it hangs like a cloak above the flame. Gas mantles were also used in portable camping lanterns, pressure lanterns and some oil lamps. Gas mantles are usually sold as fabric items, which, because of impregnation with metal nitrates, burns away to leave a rigid but fragile mesh of metal oxides when heated during initial use; these metal oxides produce light from the heat of the flame whenever used. Thorium dioxide was commonly a major component; being radioactive, it has led to concerns about the safety of those involved in manufacturing mantles. Normal use, however, poses minimal health risk. Mechanism l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bunsen Burner Flame Types
Bunsen may refer to: * Christian Charles Josias Bunsen (1791–1860), Prussian diplomat and scholar * Frances Bunsen (1791–1876), or Baroness Bunsen, Welsh painter and author, wife of Christian Charles Josias Bunsen * Robert Bunsen (1811–1899), German chemist, after whom is named: ** Bunsen burner ** Bunsen cell ** Bunsen crater on the moon ** 10361 Bunsen, an asteroid ** Bunsen Reaction ** The Bunsen–Kirchhoff Award, a German award for spectroscopy * Sir Maurice de Bunsen (1852–1932), British diplomat * Dr. Bunsen Honeydew Dr. Bunsen Honeydew is a Muppet character from ''The Muppet Show'', performed by Dave Goelz. He is a bald, yellow-skinned, bespectacled, lab-coated scientist who presented periodic science segments from "Muppet Labs, where the future is being mad ..., fictional character from the Muppet Show {{surname Low German surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swan Band
Swan bands are a characteristic of the spectra of carbon stars, comets and of burning hydrocarbon fuels. They are named for the Scottish physicist William Swan, who first studied the spectral analysis of radical diatomic carbon (C2) in 1856. Swan bands consist of several sequences of vibrational bands scattered throughout the visible spectrum. See also *Spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ... References Emission spectroscopy Fire Astronomical spectroscopy Astrochemistry Carbon {{Spectroscopy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planck's Law
In physics, Planck's law describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature , when there is no net flow of matter or energy between the body and its environment. At the end of the 19th century, physicists were unable to explain why the observed spectrum of black-body radiation, which by then had been accurately measured, diverged significantly at higher frequencies from that predicted by existing theories. In 1900, German physicist Max Planck heuristically derived a formula for the observed spectrum by assuming that a hypothetical electrically charged oscillator in a cavity that contained black-body radiation could only change its energy in a minimal increment, , that was proportional to the frequency of its associated electromagnetic wave. This resolved the problem of the ultraviolet catastrophe predicted by classical physics. This discovery was a pioneering insight of modern physics and is of fundam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black-body Radiation
Black-body radiation is the thermal electromagnetic radiation within, or surrounding, a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body). It has a specific, continuous spectrum of wavelengths, inversely related to intensity, that depend only on the body's temperature, which is assumed, for the sake of calculations and theory, to be uniform and constant., Chapter 13. A perfectly insulated enclosure which is in thermal equilibrium internally contains black-body radiation, and will emit it through a hole made in its wall, provided the hole is small enough to have a negligible effect upon the equilibrium. The thermal radiation spontaneously emitted by many ordinary objects can be approximated as black-body radiation. Of particular importance, although planets and stars (including the Earth and Sun) are neither in thermal equilibrium with their surroundings nor perfect black bodies, black-body radiation is sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion Flame
In combustion, a diffusion flame is a flame in which the oxidizer and fuel are separated before burning. Contrary to its name, a diffusion flame involves both diffusion and convection processes. The name diffusion flame was first suggested by S.P. Burke and T.E.W. Schumann in 1928, to differentiate from premixed flame where fuel and oxidizer are premixed prior to burning. The diffusion flame is also referred to as nonpremixed flame. The burning rate is however still limited by the rate of diffusion. Diffusion flames tend to burn slower and to produce more soot than premixed flames because there may not be sufficient oxidizer for the reaction to go to completion, although there are some exceptions to the rule. The soot typically produced in a diffusion flame becomes incandescent from the heat of the flame and lends the flame its readily identifiable orange-yellow color. Diffusion flames tend to have a less-localized flame front than premixed flames. The contexts for diffusion may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
