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| [[File:lighterstill.jpg]][[File:SHA-POROSITY.jpg|right|frame]] | | [[File:lighterstill.jpg]][[File:SHA-POROSITY.jpg|right|frame]] |
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− | *[http://en.wikipedia.org/wiki/14th_century] | + | *[https://en.wikipedia.org/wiki/14th_century] |
| ==Definitions== | | ==Definitions== |
| *1a : possessing or full of pores | | *1a : possessing or full of pores |
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| *3: capable of being [[penetrated]] <porous national boundaries> | | *3: capable of being [[penetrated]] <porous national boundaries> |
| ==Description== | | ==Description== |
− | '''Porosity''' or ''void fraction'' is a measure of the void (i.e., "empty") spaces in a [[material]], and is a fraction of the [[volume]] of voids over the total volume, between 0–1, or as a percentage between 0–100%. The term is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, [[earth science]]s, [http://en.wikipedia.org/wiki/Soil_mechanics soil mechanics] and [http://en.wikipedia.org/wiki/Engineering engineering]. | + | '''Porosity''' or ''void fraction'' is a measure of the void (i.e., "empty") spaces in a [[material]], and is a fraction of the [[volume]] of voids over the total volume, between 0–1, or as a percentage between 0–100%. The term is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, [[earth science]]s, [https://en.wikipedia.org/wiki/Soil_mechanics soil mechanics] and [https://en.wikipedia.org/wiki/Engineering engineering]. |
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− | In gas-liquid [http://en.wikipedia.org/wiki/Two-phase_flow two-phase flow], the void fraction is defined as the fraction of the flow-[[channel]] volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow channel (depending on the two-phase [[flow]] pattern). It fluctuates with [[time]] and its [[value]] is usually time averaged. In separated (i.e., non-homogeneous) flow, it is related to volumetric flow rates of the [[gas]] and the [[liquid]] phase, and to the [[ratio]] of the [[velocity]] of the two phases (called ''[http://en.wikipedia.org/wiki/Slip_ratio_(gas-liquid_flow) slip ratio)]''. | + | In gas-liquid [https://en.wikipedia.org/wiki/Two-phase_flow two-phase flow], the void fraction is defined as the fraction of the flow-[[channel]] volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow channel (depending on the two-phase [[flow]] pattern). It fluctuates with [[time]] and its [[value]] is usually time averaged. In separated (i.e., non-homogeneous) flow, it is related to volumetric flow rates of the [[gas]] and the [[liquid]] phase, and to the [[ratio]] of the [[velocity]] of the two phases (called ''[https://en.wikipedia.org/wiki/Slip_ratio_(gas-liquid_flow) slip ratio)]''. |
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− | Used in geology, hydrogeology, soil science, and building science, the ''porosity'' of a porous [[medium]] (such as rock or sediment) [[describes]] the [[fraction]] of void space in the [[material]], where the void may contain, for example, [[air]] or [[water]]. [http://en.wikipedia.org/wiki/Porous] | + | Used in geology, hydrogeology, soil science, and building science, the ''porosity'' of a porous [[medium]] (such as rock or sediment) [[describes]] the [[fraction]] of void space in the [[material]], where the void may contain, for example, [[air]] or [[water]]. [https://en.wikipedia.org/wiki/Porous] |
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| [[Category: Earth Science]] | | [[Category: Earth Science]] |