Paste (rheology)
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2008-06-19T15:59:11Z
Srleffler
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See also gel.
:For other meanings of paste see [[Paste|Paste (disambiguation)]]
{{Unreferenced|date=November 2007}}
In [[physics]], a '''paste''' is a substance that behaves as a [[solid]] until a sufficiently large load or [[stress (physics)|stress]] is applied, at which point it flows like a [[fluid]]. In [[rheology|rheological]] terms, a paste is an example of a [[Bingham plastic]] [[fluid]].
Pastes typically consist of a [[suspension (chemistry)|suspension]] of [[granular material]] in a background fluid. The individual grains are jammed together like [[sand]] on a [[beach]], forming a disordered, [[glass]]y or [[amorphous]] structure, and giving pastes their solid-like character. It is this "jamming together" that gives pastes some of their most unusual properties; this causes paste to demonstrate properties of [[fragile matter]].
In pharmacology, '''paste''' is basic [[pharmaceutical form]]. It consists of fatty base (e.g., [[petroleum jelly]]) and at least 25% solid substance (e.g., [[zinc oxide]]).
Examples include [[starch]] pastes, [[toothpaste]], [[Mustard (condiment)|mustard]], and [[putty]].
==See also==
*[[Gel]]
[[Category:Materials]]
[[Category:Pharmacology]]
{{material-stub}}
[[de:Paste (Stoff)]]
[[da:Masse (materiale)]]
[[cs:Pasta]]
[[lt:Pasta]]