Subject:
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Re: Darn those definitions (was: The new Super Car)
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 8 Aug 1999 13:22:34 GMT
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Original-From:
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Shawn Menninga <SMQ@DWARFRUNE.spamcakeCOM>
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Viewed:
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1221 times
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At 19:53 07-08-99 GMT, Kevin Baker wrote:
> In lugnet.robotics, lego-robotics@crynwr.com (Jim Choate) writes:
> >
> > A liquid is an incompressible fluid.
> >
> > A gas is a compressible fluid.
>
>
> I think you will find that, with the exception of black hole stuff,
> everything is compressible.
Disregarding definitions for the moment and returning to the original
question (can Lego rightly call those parts hydraulic), can we all agree
on the following:
1) There is a large group of fluids whose volume changes *almost*
linearly with static pressure. At twice the static pressure they occupy
approximately half the volume. This group of materials includes (at STP)
oxygen, nitrogen, xenon, helium, and normal atmospheric air, along with
many others. A mechanical device which makes use of such a fluid to do
useful work is classified as "pneumatic".
2) There is a large group of fluids whods volume changes *almost* not
at all with static pressure. At twice the static pressure they occupy
approximately the same volume. This group of materials includes (as STP)
ethenol, machine oil, mercury, brake fluid, and normal water, along with
many others. A mechanical device which makes use of such a fluid to do
useful work is classified as "hydraulic".
Now, with out bothering to mathematically define "almost" and ignoring
those fluids which don't fall into either category, it is still clear that
the device in question is pneumatic, not hydraulic. Fair enough? :-)
-SMQ Shawn Menninga smq@dwarfrune.com
--=--=--=--=--=--=--=--=--=--=--=--=---=--=--=--=--=--=--=--=--=--=--=--=--
"Well I've wrestled with reality for thirty-five years now, doctor, and I'm
happy to state I've finally won out over it." -- Elwood P. Dowd, Harvey
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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