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. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five This page is about the physical properties of gas as a state of matter For freezing as a method of food preservation see Frozen food. Absorption, in Chemistry, is a physical or chemical Phenomenon or a process in which Atoms Molecules, or Ions enter some Adsorption is a process that occurs when a gas or liquid Solute accumulates on the surface of a solid or a liquid (adsorbent forming a film of molecules or atoms (the [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. Sublimation of an element or compound is a transition from the Solid to Gas phase with no intermediate liquid stage Evaporation is the process by which Molecules in a Liquid state (e In Thermodynamics, phase transition or phase change is the transformation of a thermodynamic system from one phase to another Desorption is a Phenomenon whereby a substance is released from or through a surface A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called Boiling is generally thought of as a separate phenomenon from outgassing because it occurs much more rapidly. Boiling (also called ebullition) a type of Phase transition, is the rapid vaporization of a Liquid, which typically occurs when a liquid
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Outgassing in a vacuum
Outgassing is a challenge to creating and maintaining clean high-vacuum environments. This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. 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. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Thermal radiation is Electromagnetic radiation emitted from the surface of an object which is due to the object's Temperature. A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. Materials not normally considered absorbent can release enough light-weight molecules to interfere with industrial or scientific vacuum processes. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Even metals and glasses can release gases from cracks or impurities, but moisture, sealants, lubricants, and adhesives are the most common sources. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many A sealant is a viscous material that changes state to become solid once applied and is used to prevent the penetration of Air, Gas, Noise, Dust A lubricant (sometimes referred to as a "Lube" is a substance (often a liquid introduced between two moving surfaces to reduce the Friction between them improving Glue or adhesive is a compound that adheres or bonds two items together The rate of outgassing increases at higher temperatures because the vapour pressure and rate of chemical reaction increases. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium 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.
NASA's Stardust spaceprobe suffered reduced image quality due to an unknown contaminant that had condensed on the CCD sensor of the navigation camera. Stardust is an American interplanetary mission of the NASA Jet Propulsion Laboratory, whose primary purpose was to investigate the makeup of the A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors A similar problem affected the Cassini-Huygens spaceprobe's Narrow Angle Camera, but was corrected by repeatedly heating the system to 4 degrees Celsius. Cassini–Huygens is a joint NASA / ESA / ASI Robotic spacecraft mission currently studying the planet Saturn and its The Celsius Temperature scale was previously known as the centigrade scale.
Outgassing from rock
Outgassing is the source of many tenous atmospheres of terrestrial planets or moons. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " A terrestrial planet, telluric planet or rocky planet is a Planet that is primarily composed of Silicate rocks Within our 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. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Materials on the lunar surface have completely outgassed and been ripped away by solar winds long ago, but volatile materials may remain at depth. The lunar surface (or the surface of the Moon) differs greatly from that of Earth. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. Once released, gases almost always are less dense than the surrounding rocks and sand and seep toward the surface. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles The lunar atmosphere probably originates from outgassing of warm material below the surface. The atmosphere of the Moon is very tenuous and insignificant in comparison with that of the Earth. 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. In Plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a In Geology, a crust is the outermost solid shell of a planet or moon Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single The mantle is a part of an Astronomical object. The interior of the Earth, similar to the other Terrestrial planets, is Chemically divided Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet
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. New car smell is the common term for the Odor that comes from the combination of materials found in new Automobiles Some people regard it as a pleasant and desirable 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. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. For example, the European Commission has banned the use of DEHP (di-2-ethyl hexyl phthalate) in PVC manufacturing due to such concerns. The European Commission (formally the Commission of the European Communities) is the executive branch of the European Union. Bis(2-ethylhexylphthalate, commonly abbreviated DEHP is an Organic compound with the formula C6H4(CO2C8H172 Some types of RTV sealants outgas the poison cyanide for weeks after application. A cyanide is any Chemical compound that contains the cyano group (C≡N which consists of a Carbon Atom triple-bonded to a These outgassing poisons are of great concern in the design of submarines and space stations.
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
- ^ Strong, John (1938). Procedures in Experimental Physics. Bradley, IL: Lindsay Publications. , Chapter 3
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