X-Message-Number: 3845
Date: Mon, 13 Feb 1995 22:18:40 MST
From: "Richard Schroeppel" <>
Subject: Cracking experiments

Bob Ettinger reports that Dr. Pichugin has verified that a particular
slow freezing schedule avoids the cracking problem.  I'd like to know
some more about cracking:  Could Dr. Pichugin follow the Alcor
protocols that resulted in cracks, and verify that his experimental
setup does get cracks?  (I.e., that the sheep-head method does show
up a cracking problem where one is known to exist.)  Secondly, could
someone develop a heat-transfer model that predicts (non)cracking
based on cooling rates & whatever other factors are relevant?  I'm
envisioning something that uses anatomical information to model
thermal stress in a cooling head.

If slow cooling is the only important factor, this would suggest that
either rapid cooling causes cracks at the time of cooling (which went
unnoticed), or r.c. freezes in a stress pattern that eventually cracks -
and that slow cooling of a solid nevertheless allows stress release.
I find both alternatives somewhat implausible.  A third disquieting
possibility is that cooling at any speed freezes in a stress pattern,
and even the slow-cooled sheep-heads would crack if left in the LN2
dewar for a couple of years.

What is known about patient fragility?  Has Alcor examined their
patients after the move to Phoenix?

Rich Schroeppel   



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