X-Message-Number: 4734
Date: Mon, 7 Aug 1995 22:52:22 -0400
From: "Keith F. Lynch" <>
Subject: SCI.CRYONICS Cold Start

Ralph Merkle <> writes:
> Find chemicals that react at 140 kelvins which produce a relatively
> innocuous compound (2H2 + O2 would be ideal, except they don't react
> at that temperature).

What about monatomic oxygen and/or monatomic hydrogen?  I'm sure
either substance will react with the other, or with itself, at that
temperature, releasing lots and lots of energy, and nothing toxic.

What I'm not sure of is whether either substance can be kept stable at
that temperature.  Perhaps if the individual atoms were constrained
in a latticework of some relatively inert element such as gold?
(If nanotechnology can use diamonds, why not gold?)

Alternatively, why not simply use RF heating?  A low frequency will
penetrate evenly to all parts of the brain, with no hot spots from
shielding, focussing, reflection, diffraction, or any other mechanism.

However, with any method of very rapid heating, wouldn't there be
a shockwave?  Granted that the shockwave fronts might tend to all
cancel out, the fact remains that the brain has some non-zero
coefficient of expansion (or perhaps contraction?).  If the center
remains at rest, what acceleration will the outside of the brain
endure as it changes to its 98.6 F size in a microsecond?  Brains
are very intolerant of sudden accelerations.

How slowly can we thaw it and still avoid runaway crystallization?
Perhaps we can take several seconds or minutes to get just below
the danger range, then rush through that range in a few milliseconds,
and then take several more seconds or minutes to reach 98.6 ?

As for your question as to what to store F2 and HF in, they are
usually stored inside metal canisters lined with metal fluorides.
Presumably the same would work on the nano-scale.  Or we could use
diamond lined with diamond-fluoride (a variant of teflon).

Charles Platt <> writes:
> ... the product of this reaction, in the presence of water, produces
> hydrofluoric acid,

Right.

> which my old chem teacher used to use for cleaning especially dirty
> laboratory glassware, since it would dissolve just about anything.

I don't think so.  For one thing, it's much too toxic to be handled
except in special facilities that keep HF in the air down to the
parts-per-billion level.  For another thing, one of the things it
dissolves is laboratory glassware!

> And what happens if a couple dozen of the billions of these little
> critters somehow miss the instruction and get left behind?

Since they are sealed, not much.  If one or two of those couple dozen
break open each year, that would be harmless.  HF is really quite
non-toxic in a dose *that* small.
--
Keith Lynch, 
http://www.access.digex.net/~kfl/


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