Well, I guess we all knew "deep down" that Bill Mee and the rest of the
WKPP troglodytes couldn't and wouldn't try to understand what Dan was
writing about. What is it about the word "MUST" that you don't understand
Bill?

pH

At 01:22 PM 10/1/98 -0400, Bill Mee wrote:
>Daniel Reinders Wrote:
>
>=93 Yup those aren't typos. Apparently,by my model, all the above is true,=
 but
>if
>you MUST do a spike, you are better off postponing it towards the end of=
 the
>dive. =93=85=85
>
>The WKKP steering committee has voted overwhelmingly to nominate Daniel
>Reinders for it=92s prestigious Lockwood award.  His astounding discoveries
>and proclamations have really changed the way we think. According to=
 Daniel=92
>s model we should safely be able to spike our oxygen the longer we are
>exposed.   Danny has generously and selflessly shared this valuable
>information with others on the rebreather list and techdiver who, I am=
 sure,
>will put it to good use.
>
>Along the same lines Daniel is using principles of variational calculus,
>optimal control theory and stochastic resonance to prove that under certain
>unique circumstances the probability of bubble formation  vanishes to zero
>the longer and deeper you dive if you spike to the surface.  Similar=
 methods
>were successfully used to develop the infinite improbability drive system
>featured in the =93Hitchhikers Guide to the Universe=94. The idea of being=
 in
>two places at once is nothing new to people well versed in quantum
>mechanics, so don=92t laugh. Remember =93Schroedinger=92s Cat=94 ?
>
>If you have been following Daniel=92s =93press releases=94 regarding his
>discoveries and mathematical modeling accomplishments you should be aware
>that he is planning on using rodents and other less complex animal models=
 to
>test his theories. This is most laudable, excepting those of you who are
>animal rights activists; however, we feel that something slightly higher on
>the evolutionary scale would be more appropriate, such as primates.  In
>particular we were thinking that certain species of boat or dive shop
>=93monkee=94 would provide for more credible results.
>
>Knowing great talent when we see it and not wanting the competition (i.e.
>the USDCT) to get their hands on another rocket scientist we quickly
>inducted Daniel into the project.  He has been very busy, of late, working
>on his science fair projects and new theories and really has not had the
>time to complete his open water dive training.  Under our tutelage he will
>receive first: swimming lessons and then training in excavation and
>euthanasia before commencing his course in rebreathers.  Unfortunately, he
>will have to provide his own shovel for this phase of the course.
>
>And Danny, keep on breathing that EANX 50 at 120ft and you or someone else
>will get a chance to use that new shovel.
>
>Best regards,
>
>
>Bill
>
>-----Original Message-----
>From: Daniel Martin Reinders <z4d2@ug*.cs*.ub*.ca*>
>To: diver@ch*.ne*.au* <diver@ch*.ne*.au*>; Walter Starck
><wstarck@oz*.co*.au*>
>Cc: rebreather@nw*.co* <rebreather@nw*.co*>
>Date: Wednesday, September 30, 1998 1:24 PM
>Subject: Re: OC bailout
>
>
>>Gordon Smith and I have been playing around with trimix (and heliox this
>>weekend).  One of the consequences of this has been dealing with the need
>for
>>larger amounts of bailout (based upon the Buhlmann approach to helium).
>Since
>>lifesupport is rarely limiting, decompression obligations are much less
>>formidible on an RB.  Assuming it works well, but this can get you if it
>craps
>>out on you.
>>
>>Example.  On 50% He/50% N2 inert gas mix (yes, 20% o2 as well) at .9 cubic
>>ft/min a 30 cubic foot pony of 50% nitrox is good down to 120 feet for 30
>min
>>or 150 feet for about 20 min.  But after 30 min at 150 feet I calculate
>needing
>>75 cubic feet of 50% nitrox, due to the need for deep stops.  At 200 feet,
>for
>>18 minutes I calculate 112 cubic feet of 50% for bailout.  It really=
 starts
>to
>>add up.  Soon one realises a BOB (bailout breather) is the best solution.
>> Essentially the bailout requirements become the new equivilant to the "no
>deco
>>limit".  We're looking at the feasibility of making our own trimix
>rebreather
>>computer and if it should come about I think automatic calculation bailout
>>requirements and bailout deco profile (or at least the ceiling) will have
>to be
>>part of the package.
>>
>>Now these decompressions were calculated using my standard 2 foot j-factor
>>(keeps you 2 feet below your ceiling all the way up).  But not with my
>"deep
>>stop" or "high% Oxygen penalty" conservatism.  So the deco could be=
 speeded
>up.
>> But here's my thinking on this.  It seems to me the point of bailout is=
 to
>>ensure that a failed rebreather is not an emergency.  So just because your
>>rebreather is toast, should you compromise your decompression safety?
>>
>>Incidentally, what sort of bailout allowances do other divers in=
 rebreather
>>land use?
>>
>>Regards,
>>
>>Daniel Reinders
>>
>
>So lately, amongst other little side projects, I've been thinking a bit
>about
>the danger of oxygen spikes.  You know, say on a pure o2 breather you dip
>below 30 feet and find you've been at 60 feet for a few minutes.  Now I've
>been tweaking my latest "pseudo-logistic" model for oxytox (basically a
>hybrid
>oxyclock/instant model) and the simulations have gotten me thinking about
>spikes.
>
>The prevailing wisdom goes something like this (I'm loosely quoting Dr.
>Vann,
>I believe, in C2 aquacorps).  The enzymes that protect you from oxygen get
>used up and then you have greatly reduced protection from a spike.  It's=
 the
>general argument against running the rebreathers above 1.4 (we do 1.2).
>
>So here are some numbers from my model (the autocatalytic model of Harabin
>should, if I understand it work the same way).  Let's say you do a 5 minute
>spike to 60 ft Pure o2, then do 15 minutes at 30 feet.
>
>The risk is
>5@60* 1.83%
>15@30* 2.07%
>survivors for profile 96.141%
>
>Now if you do 20 minutes at 30 ft beforehand
>20@30* 0.175%
>5@60* 1.88%
>15@30* 2.36%
>survivors for profile 94.74%
>
>Now do 40 min at 30 ft first
>40@30* 0.277%
>5@60* 2.39%
>15@30* 3.22%
>survivors 94.19%
>
>survivor rate for 30 ft 60 min 99.06%
>
>Several things are obvious.  The spike is more dangerous the later in the
>dive
>it occurs.  Also the post-spike is much more dangerous than if the spike
>hadn't occured.  Okay, so everything's status quo.  But watch this.
>
>60 ft 5 min 1.71%
>30 ft 55 min 17.8%
>survivorship for profile 80.78%
>
>Yup those aren't typos.  Apparently,by my model, all the above is true, but
>if
>you MUST do a spike, you are better off postponing it towards the end of=
 the
>dive.  However in the above profile the spike itself is less dangerous.  I
>suspect that divers who have had hits may have selective memories in their
>classification system.  Dives with a big initial spike are probably=
 aborted,
>or sincethe spike was survived are thought of as having the risk over with.
>So the dive is carried on and since 40 minutes have passed since the spike
>it
>is more or less forgotten (i.e. phew I dodged that bullet).  Conversely if=
 a
>diver has a spike near the end of the dive and has a convulsion, he/she=
 will
>probably blame the spike.
>
>When I get my hamster hyperbaric chamber going, I think this will be a
>definite experiment candidate for shoring up my ideas.  Essentially it's a
>lot
>like starting a snowball down a hill.  If you start with a pebble it takes=
 a
>long time to get big.  But a spike early on throws a basketball down and=
 the
>risk takes off much faster because of the "head start".
>
>Anyhow it's not what you might expect intuitively.  I think it's rather=
 like
>the finding that cats survive falls better at 15 stories than say 10 (turns
>out to be because only the least maimed kitties were likely to even bother
>with a vet, and people who live higher up have more money and are more
>likely
>to pay for kickass vet care).  Thought I'd poke that one out as a nugget=
 for
>the list to mull over.
>
>Regards,
>
>Daniel Reinders
>=20
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