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Encyclopedia > Outgassing

Outgassing (sometimes called "Offgassing," particularly when in reference to indoor air quality) is the slow release of a gas that was trapped, frozen, absorbed or adsorbed in some material.[1] It can include sublimation and evaporation which are phase transitions of a substance into a gas, as well as desorption, seepage from cracks or internal volumes and gaseous products of slow chemical reactions. Boiling is generally thought of as a separate phenomenon from outgassing because it occurs much more rapidly. This article does not cite any references or sources. ... In chemistry, a molecule is adsorbed onto a surface when temporary bonds are formed between the surface and the molecule. ... Sublimation of an element or compound is the change from a solid directly to a gas with no intermediate liquid stage. ... This article or section is in need of attention from an expert on the subject. ... In physics, a phase transition, (or phase change) is the transformation of a thermodynamic system from one phase to another. ... Boiling, a type of phase transition, is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmospheric pressure. ...

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Outgassing in a vacuum

Outgassing is a challenge to creating and maintaining clean high-vacuum environments. NASA maintains a list of low-outgassing materials to be used for spacecraft, as outgassing products can condense onto optical elements, thermal radiators, or solar cells and obscure them. Materials not normally considered absorbent can release enough light-weight molecules to interfere with industrial or scientific vacuum processes. Even metals and glasses can release gases from cracks or impurities, but moisture, sealants, lubricants, and adhesives are the most common sources. The rate of outgassing increases at higher temperatures because the vapour pressure and rate of chemical reactions increases. For most solid materials, the method of manufacture and preparation can reduce the level of outgassing significantly. Cleaning surfaces or baking individual components or the entire assembly before use can drive off volatiles. Look up Vacuum in Wiktionary, the free dictionary. ... The National Aeronautics and Space Administration (NASA) is an agency of the United States federal government, responsible for the nations public space program. ...


NASA's Stardust spaceprobe suffered reduced image quality due to an unknown contaminant that had condensed on the CCD sensor of the navigation camera. A similar problem affected the Cassini-Huygens spaceprobe's Narrow Angle Camera, but was corrected by repeatedly heating the system to 4 degrees Celsius. An artists rendering of Stardust (NASA image) The Stardust capsule with cometary and interstellar samples landed at the U.S. Air Force Utah Test and Training Range at 10:10 UTC (15 January 2006) in the Bonneville Salt Flats. ... A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... Cassini-Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ...


Outgassing from rock

Outgassing is the source of many tenous atmospheres of terrestrial planets or moons. Many materials are volatile relative to the extreme vacuum of space, such as around the Earth's Moon, and may evaporate or even boil at ambient temperature. Materials on the surface have completely outgassed and been ripped away by solar winds long ago, but volatile materials may remain at depth. Once released, gases almost always have a lighter density than the surrounding rocks and sand and seep toward the surface. The Moon's atmosphere probably originates from outgassing of warm material below the surface. At the Earth's tectonic divergent boundaries where new crust is being created, helium and carbon dioxide are some of the volatiles being outgassed from mantle magma. Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... A terrestrial planet or telluric planet is a planet which is primarily composed of silicate rocks. ... Apparent magnitude: up to -12. ... In plate tectonics, a divergent boundary (divergent fault boundary or divergent plate boundary), (but also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms, and is in a gaseous state in the atmosphere of the Earth. ... Earth cutaway from core to exosphere. ... Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ...


Outgassing in a closed environment

Outgassing can be significant if it collects in a closed environment where air is stagnant or recirculated. This is, for example, the origin of new car smell. Even a nearly odourless material such as wood may build up a strong smell if kept in a closed box for months. There is some concern that softeners and solvents that are released from many industrial products, especially plastics, may be harmful to human health. For example, the European Commission has banned the use of DEHP (di-2-ethyl hexyl phthalate) in PVC manufacturing due to such concerns. Some types of RTV sealants outgas the poison cyanide for weeks after application. These outgassing poisons are of great concern in the design of submarines and space station. The new car smell many of us find pleasurable comes from chemicals that can pose health risks. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... The Commission seat in Brussels The European Commission (formally the Commission of the European Communities) is the executive body of the European Union. ... bis(2-ethylhexyl)phthalate Bis(2-ethylhexyl)phthalate (also BEHP, di-2-ethyl hexyl phthalate, DEHP, or dioctyl phthalate, DOP) is a phthalate , a branched-chain dioctyl ester of phthalic acid. ... Polyvinyl chloride Polyvinyl chloride, (IUPAC Polychloroethene) commonly abbreviated PVC, is a widely used thermoplastic polymer. ... The cyanide ion, CN−. From the top: 1. ...


See also

This article does not cite any references or sources. ...

External links

  • Outgassing Data for Selecting Spacecraft Materials Online
  • Outgassing Data For Common Materials
  • Outgassing data for some nonmetallic materials (table 3)
  • ESA Outgassing Data for Spacecraft Materials according to ECSS-Q-70-02

Notes

  1. ^ Strong, John (1938). Procedures in Experimental Physics. Bradley, IL: Lindsay Publications. , Chapter 3

  Results from FactBites:
 
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Increased net CO outgassing in the upwelling region of the southern Bering Sea in a period of variable marine climate between 1995 and 2001
Highest net CO outgassing was observed in the relatively cold years of 1999 and 2000, whereas the exceedingly warm year 1997 showed four times lower CO flux to the atmosphere.
Citation: Fransson, A. Chierici, and Y. Nojiri (2006), Increased net CO outgassing in the upwelling region of the southern Bering Sea in a period of variable marine climate between 1995 and 2001, J.
Outgassing - Wikipedia, the free encyclopedia (531 words)
Outgassing is the slow release of a gas that was trapped, frozen, absorbed or adsorbed in some material.
Outgassing is a challenge to creating and maintaining clean high-vacuum environments.
Outgassing is the source of many tenous atmospheres of terrestrial planets or moons.
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