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From: rpw3@amdcad.UUCP (Rob Warnock)
Newsgroups: sci.misc
Subject: Re: Fluids and solids (was Re: H-less liquids)
Message-ID: <13479@amdcad.UUCP>
Date: Thu, 23-Oct-86 00:48:09 EDT
Article-I.D.: amdcad.13479
Posted: Thu Oct 23 00:48:09 1986
Date-Received: Thu, 23-Oct-86 18:50:15 EDT
References: <17@wjh12.HARVARD.EDU> <666@faron.UUCP> <18@wjh12.HARVARD.EDU> <1454@jade.BERKELEY.EDU>
Distribution: net
Organization: [Consultant] San Mateo, CA
Lines: 19
Keywords: fluid solid viscosity deformation thixotropic
Summary: "Thixotropic" defined

In article <1454@jade.BERKELEY.EDU>, dean@ruby.berkeley.edu writes:
> An interesting thing about this definition is that it may be time-dependent
> for real materials: a thick solution of corn starch in water will flow if
> poured slowly (it's a liquid at that timescale) but shatters if hit with a
> hammer (in that case it's a solid).  There is a continuum of behaviors from
> a perfectly elastic solid to a perfectly Newtonian fluid.

Conversely, there are materials which are called "thixotropic" (spelling?),
which are solids if stressed slowly and liquids if stressed quickly. A good
(or should I say, bad) example are certain kinds of mud (or wet ground, as
after a long rain) which, when a small earthquake comes, suddenly liquify
and bury people. Another example is a kind of heavy stucco paint, which
sprays quite tamely through a paint sprayer (liquid), but which as soon as
it lands becomes "solid", allowing one to spray extremely thick, built-up
layers on a vertical wall.

Rob Warnock
Consultant
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