lastwords

permeate

1-6
English German
to permeate vt. durchdringen
  eindringen
  imprägnieren
  penetrieren
  permeieren
permeate subst. das Permeat n
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Permeate aus Wikipedia. Zum Beitrag

Permeation - Wikipedia, the free encyclopedia a.new,#quickbar a.new{color:#ba0000} /* cache key: enwiki:resourceloader:filter:minify-css:5:f2a9127573a22335c2a9102b208c73e7 */ Permeation From Wikipedia, the free encyclopedia   (Redirected from Permeate) Jump to: , Permeation, in physics and engineering, is the penetration of a permeate (such as a liquid, gas, or vapor) through a solid, and is related to a material's intrinsic permeability. Permeability is tested by permeation measurement, for example by a minipermeameter.

Contents

Description

The permeate always migrates to the lower concentration in three steps: Sorption (at the interface): Gases, vapour or dissolved chemicals or suspended substances are adsorbed at the surface of the solid. Diffusion (through the solid): The permeate penetrates the solid material through pores or molecular gaps. Desorption: The adsorbate leaves the solid as a gas.

Related terms

Permeate: The substance permeating through the solid. Permeability: The grade of transmissibility of a solid, meaning how much penetrates in a specific time, dependent on the type of permeate, pressure, temperature, thickness of the solid and the area size. Semipermeability: Property of a material to be permeable only for some substances and not for some others. Permeation measurement: Method for the quantification of the permeability of a material for a specific substance.

History

Abbé Jean-Antoine Nollet (physicist, 1700?1770)

Nollet tried to seal wine containers with a pig's bladder and stored them under water. After a while the bladder bulged outwards. He noticed the high pressure that discharged after he pierced the bladder. Curious, he did the experiment the other way round: he filled the container with water and stored it in wine. The result was a bulging inwards of the bladder. His notes about this experiment are the first scientific mention of permeation (later it would be called semipermeability).

Thomas Graham (chemist, 1805?1869)

Graham experimentally proved the dependency of gas diffusion on molecular weight, which is now known as Graham's law.

Richard Barrer (1910?1996)

Barrer developed the modern "Barrer" measurement technique, and first used scientific methods for measuring permeation rates.

Permeation in everyday life

Packaging: The permeability of the package (materials, seals, closures, etc) needs to be matched with the sensitivity of the package contents and the specified shelf life. Some packages must have nearly hermetic seals while other can (and sometimes must) be selectively permeable. Knowledge about the exact permeation rates is therefore essential. mehr

Permeate aus Wikipedia. Zum Beitrag


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