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Re: Bernoulli (horizontal)



At 9:02 AM -0700 on 11/19/01, John Mallinckrodt wrote
On Mon, 19 Nov 2001, Chuck Britton wrote:

I am quite surprised that diamond has this much 'hysteresis' as it it
squeezed and released.

Wouldn't we expect the expansion on release to be pretty close to the
initial compression.

I don't understand your question. It's not a matter of
hysteresis; its purely a matter of compressibility. I would
expect diamond to compress and expand by about the same very small
amount. It might take a few tens of joules of work to compress
1 cm^3 of diamond to 50 kbars (=5 kJ/cm^3) and about the same
amount of work would be done *by* the diamond as the pressure is
removed.


EXACTLY

and I thought that John was wanting to equate the compressional work
as being 'stored', or revealing itself or whatever, as the Pressure
in the diamond while compressed.

perhaps I was misreading something in the following exchange.


On Mon, 19 Nov 2001, John Barrer wrote:

> John - In response to #2 below: some external agent
> was responsible for the applied force which resulted
> in the pressure on the diamond. The 5000J of pressure
> energy show up as "work done" on the external agent as
> the pressure is released.

This would only be true if the volume of the diamond increases
very substantially, like by a factor of three, as the pressure is
reduced. In fact the volume of the diamond will increase
by a tiny fraction, perhaps 1% at most, as the pressure is
reduced. Thus the work done on the external agent will be a few
tens of joules at best.
--

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Chuck Britton Education is what is left when
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