X-Message-Number: 4188
Date: 11 Apr 95 17:03:19 EDT
From: Mike Darwin <>
Subject: SCI.CRYONICS Mirrors and cracks


Yvan Bozonetti's post on preparation of telescope mirrors was of great interest.

The problem of cooling large masses of glass is of more relevance than Yvan
thinks since cryopreservation patients do contain large amounts of glass.  In

fact, a patient treated with 50% glycerol (7+ M) will be nearly half glass.  And

it will be a weak glass because of its interleaving with ice and the fundamental
nature of glycerol-water glasses.

Is the Angel that Yvan talks about the same as the C.A. Angell who is an expert
on glasses and was (at least recently) at Purdue University in Indiana?

I think the fact that extending annealing time works for large, unstable glass
masses is of extreme interest and potential utility to cryonics.  I think it is
also important to note that while  CI, Alcor , and CryoSpan have been cooling
patients slowly (1 week or more) and in CI's case they see no cracking in sheep
brains, it is important to realize that cracking may occur during movement,
handling, etc.  Being able to prevent this by extending the annealing time to
many weeks is of great interest.  (For instance, to my knowledge CI did not
jostle, move or otherwise inject mechanical energy into the sheeps heads after
the cooled them).

Finally, can Yvan provide me with references on Angel's rule for cooling
telescope mirrors?


Mike Darwin


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