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RE: Measurement of Viscosity

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That's my problem. The particular substance that is supposed to have a
viscosity of "between 250 and 400 cps" is an ULTRA-LOW VISCOSITY
Polyurethane injection resin.  Therefore it could NOT be "centipoise" (which
actually is abbreviated cP, btw, since the "Poise" is a "derived" unit,
named after a real guy. In the SI system, certain "derived" units such as
Newton, Pascal, etc., named after people, are supposed to be capitalized, or
abbreviated with capitals).



William L. Polhemus, Jr. P.E.
Polhemus Engineering Company
Katy, TX, USA
Phone (281) 492-2251
FAX (281) 492-8203
email bill(--nospam--at)polhemus.cc

-----Original Message-----
From: Christopher Wright [mailto:chrisw(--nospam--at)skypoint.com]
Sent: Friday, January 11, 2002 9:52 AM
To: ?
Subject: Re: Measurement of Viscosity

>Is 0.0 centipoise the consistancy of fresh water?
No. No real fluid has zero viscosity, which implies that an object would
move in the fluid without drag.

Just for cultural value, the viscosity relates the shearing stress in a
moving fluid to the velocity gradient: shear equals viscosity times
velocity gradient. As a result the viscosity has units of
stress/(velocity/length) or (force)(time)/length^2). For so-called
Newtonian fluids, which doesn't include resins, the viscosity is constant.

One other thing--lot of weird units associated with viscosity from the
SAE numbers to SSU, which derives from a particular testing device. I've
never seen 'cps' used for viscosity units. Centipoise is sometimes
abreviated cp. Water has a room temperature viscosity of 2 centipoise.
200 centipoise is somewhere between crude oil and glycerin.

Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw


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