X-Message-Number: 2187 Date: Sat, 1 May 93 14:48:33 CDT From: Brian Wowk <> Subject: CRYONICS Reply to Mike Darwin Mike Darwin: > At this point I feel there is little danger of Brian's system of > sleeping bags only being adopted since virtually all cryonics > organizations have seen the wisdom of pods and gone to them. The great benefit of thinking out loud in this forum is that your ideas are scrutinized and optimized by many minds. The great risk is that from time to time your thoughts are exposed as foolish. Thanks to Mike for clarifying the importance of patient cassettes. > I stand by my remarks about small plastic containers. Also, these > containers are liable to be glass brittle and/or spontaneously crack > at the temperatures being proposed for their use. I think your best > bet would be to have cells and ballast compartments engineered out > of welded polypropylene. In my most recent message on the subject, I too have rejected small plastic containers in favor of *large* plastic containers. I think the removable ballast should be in 20 gallon (160lb) cylindrical plastic barrels (which, if I'm not mistaken, are made from polypropylene). I believe the permanent ballast should be in the form of pillars distributed throughout the room. Pillars of ballast are better than walls of ballast because they are less prone to flexing under loads. (In fact, this is why pillars were invented.) Pillars provide stronger vertical support than walls of the same weight. Pillars could be made by stacking ballast barrels within a bracing framework. Alternatively, tall polypropylene tanks could be manufactured as Mike suggests. Such tanks could be assembled and tested as discrete units outside the room. This would be cheaper and easier than making extensive use of polypropylene as structural material within the room. Polypropylene might not be the final answer either. My science encyclopedia notes that polypropylene exhibits "poor impact strength below -10'C." We should freeze some plastic and steel barrels of water to -130'C in a LN2 dewar, and see how they fare. If plastic doesn't withstand the punishment, we might find it necessary to use steel barrels for everything (including pillars). --- Brian Wowk Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=2187