X-Message-Number: 2105
Date: 14 Apr 93 01:13:22 EDT
From: Mike Darwin <>
Subject: CRYONICS Re Coldroom Discussion
> From: Mike Darwin
> To: Brian Wowk, All
> Date: 11 April, 1993
The first thing I want to say is to Brian: I have found your cold
room postings fascinating and very worthwhile. I do not have the time
to discuss your proposals in detail as I am swamped with work right
now.
However, there are several things both general and specific which
I want to say:
1) Water is real problem for underground and above ground
structures. We are located in Southern California which is not the
wettest part of the world. However, this last winter it rained, and
rained, and rained. Forget the floods, they were bad enough! What I
want to report on is more subtle and probably MORE of a problem. Our
facility is located on high ground so there is no danger of flooding.
The concrete pad is at least a foot thick and on top of that is a
tiled floor (asphalt tile). When the soil became saturated the wet
soil pressure (presumably the weight of the building on the soil,
etc.) was sufficient to hydraulically extrude water through the cracks
in the tile. The water was an annoyance, but the tile adhesive it
squeezed out was a REAL pain the ass; I'm still wiping it off the
tiles with solvent. In the back of the building the floor got wet
wherever it was occluded from air by impermeable material.
The first time I saw this phenonemon was when I stored an
expensive dining room table (made of wood) for Al Lopp under my bed on
the floor. When he picked it up a year later it was soaking wet (and
so was the carpet under it). My second experience was at the Alcor
building: Carpeting would get wet under plastic carpet protectors and
the rubber mat at the front door. Hugh Hixon refused (and still
refuses) to believe that this was ground water because he couldn't see
salt deposits on the carpet. He claimed it was condensation from the
air under the mats and plastic protectors. This is incorrect and it
is important that everyone understand this: it comes from water being
pushed through the slab. Facility design must take the permeability
of the concrete into account. Incidentally, this happended at Alcor
during the summer months too.
2) I come from the Midwest and I have learned the hard way that
the lessons I learned there apply in relatively dry climes like
Southern California too: A) Never buy or build a building with a flat
roof: they all leak sooner rather than later. Any architect who
builds a building with a flat roof should be stripped of his
credentials, placed in a flat roofed building under a leak and slowly
drowned as water fills up the tub s/he has been placed in one drop on
his/her forehead at a time. B) All basements are damp and wet and
all concrete walls, no matter how carefully treated with sealent
inside and out (and I've seen just about every strategy used, since I
have hung around insecure nuts prone to building underground
structures since my youth) leaks water.
3) Ethyl alcohol is probably not acceptable for several reasons:
A) It is a fire hazard which will send the fire department into orbit.
I have two 55 gallon drums of it and the fire department still hasn't
stopped crawling all over me. They HATE the stuff, they HATE
flammable liquids. It will be used against you by the competition
because it is a fire hazard. B) No, warming up even a little (more
than a few degrees) is NOT acceptable if you have vitrified rather
than frozen patients. Why? Because of a phenomenon known as
devitrification. Unless you rewarm VERY rapidly or use enormous
concentrations of cryoprotectant ice forms when you warm vitreous
solutions. Efforts are under way to use recombinant thermohysteresis
proteins to block crystal growth, but to my knowledge these efforts
have not been successful. Slight amounts of warming are likely to
cause cracks in frozen (as opposed to vitrified) tissues (see
discussion below).
4) Brian is dead wrong if he thinks that patients stored in LN2
will be removed to -135*C storage. The objections others have raised
are valid and what is more, there is very likely to be no money or
incentive to do the careful scientific studies that would be required
to justify a change in these patient's conditions. The concerns about
cracking or its consequences being exacerbated are valid and what is
more, I believe there is evidence to support them. The first
patient's body I autopsied after suspension (RM) had been rewarmed to
-80*C then cooled down to -196*C again: both times very slowly. I
knew there were problems right away because his skin fractures (in
sharp contrast to the other patients) looked like peeling paint in
a tenement. The skin had lifted up a bit and pulled away from the edge
of the fracture EXACTLY like peeling paint. I say leave the patients
at the temperature they are at. Hell, I'm concerned about the small
fuctuations in temp. I've seen while filling dewars.
5) I think others have commented on this but I wish to put my
two cents worth in. Thermal stratification is nontrivial. I cannot
say this strongly enough. Furthermore, I think your conduction
schemes are unlilkely to hold up very well in reality. I have done
experiments with a shallow (25-30") deep dewar which is about 30-40"
in diameter wherein I placed a piece of 1/4" plywood on the top and
put a couple of inches of LN2 in the bottom. Forget about convective
pumping! The whole thing stratifies beautifully with the top being
about -20*C and the bottom at -196*C. And it stays that way. Now as
to the matter of conduction, again I have some practical experience.
When I was a teenager I went to visit the Cryonics Society of New York
and I took along a pentane filled thermometer capable of measuring
temp. (so it claimed) down to -196*. I wanted to know what
temperature the patients were actually at since the dewars were only
being kept about 1/2 full and the top half of the patient (yes,
including his/her head!) was out of the liquid and under the neck
plug. This model has some relevance to the current round of
speculation because of the following points: a) the cross-section of
the dewar was largely taken up by two heavily aluminum foil wrapped
bodies which were 1/2 immersed in LN2, b) more relevant still, there
were two thick (1/2 to 3/4" ALUMINUM stretchers which the patients
were racked on also occuping the cross section and also half immersed
in the LN2. There was also an approx 1/4" fill line, plus the side
rails that supported the stretchers which were also 1/2 immersed in
LN2. The temperature near the patient's snouts was about -150*C. I
was very impressed at the time that the bodies and all that metal
didn't conduct better. Twenty years later (almost to the day!) I am
still impressed.
3) Bob Ettinger is absolutely right about using thick blocks of
insulation. Again, from practical experience I can tell you that
once you get out beyond a foot you don't seem to get much for your
(foam) money. Certainly by two feet you are almost certainly wasting
your time. I could be wrong on this, but I don't think so.
4) This point is my most important: Any attempt to engineer
large scale systems to store frozen patients is PREMATURE in the
extreme. For one thing there is not one stitch of evidence that
frozen patients cooled to near TG remain unfractured. Indeed, there
is contrary evidence. Greg has done an experiment cooling frozen and
vitrified kidneys to slightly below TG and the frozen kidneys were
cracked to hell. Anyone who has ever put an ice cube in water knows
the propensity of ice to crack, indeed anyone who has ever looked at
ice cubes in the ice tray BEFORE they are thermally stessed by
rewarming (even at -20*C) will note that they are usually multiply
fractured. More biological studies are definitely in order before
seriously considering applying this technology to patients treated by
freezing.
5) Peltier effect? Gentlemen, I doubt it. I have no fancy
physics to offer but I would offer this observation: Every
refrigeration company in the world is twisting itself into a pretzel
trying to find a way around flurocarbons. I note a conspicuous
absence of Peltier/Seebeck devices.
These devices are used commercially in analytic equipment,
particularly in osmometers. I have two osmometers with such
equipment. One I junked; the other is sitting on the shelf broken.
The manufactuers tell me that the refrigerators are good for about
ten years and then crap out like clockwork. They are RIGHT! They
cost $1,200 to replace (guess why they are on the shelf unused?).
6) Brian has once or twice asserted that Queue manufactures a
body-sized -135*C freezer. Not to my knowledge! While it is true that
the freezers LOOK body sized, the cavities of the largest models would
barely hold a few neuros in current packaging. What takes up all that
space? Two guesses: insulation and the refrigeration system.
These freezers are OK if you have lots of money and don't care
about long-term reliability. They cost in the ballpark of 10K.
Greg's, which is about 10 years old, just crapped out and went to the
shop. It has come back and when I spoke with him last he told me it
is still not working right.
Mechanical systems stink. I hate them. They are nothing but
trouble. They are not as reliable as your household refrigerator. I
don't known anything about the company Brian talks about except that
what he was told makes my skin crawl. No known failure mode, should
run decades.... Hmmmn that's just what the Queue guy told me ten years
ago! Give me a break! The household refrigerator has taken decades to
perfect and it still is grossly unreliable when considered for an
application like cryonics. It will take a powerful lot of convincing
to persuade me that a new technology has arrived on the scene which is
more reliable than consumer refrigeration which again I emphasize is
NOT reliable.
Also, the larger the refrigeration system the more unreliable.
The biggest customers for dry ice are food service places with failed
refrigerators. When they make household refrigerators they make them
under factory conditions with very close tolerances and VERY GOOD
SEALS. When you put a refrigeration set up in place in the field you
have nothing but quality control problems every step of the way. Just
getting and keeping the water out of the system is a major hassle and
a major cause of failure since it forms an ice ball on the thistle
valve in the compressor. Commercial systems are loaded with in-line
driers for the refrigerant. And you propose to do this with a NEW
technology which according to its manufactuer no one has ever seen
fail? All I have to say is "Lead me to the liquid nitrogen!!!!"
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