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Peter If you want to generate custom closed circuit (not semi) proplanner will do that. It is available as well as other deco siftware abbyssis, voyager etc thro IANTD. In addition IANTD is publishing several sets of waterproof tables with po2 set points of 1.0 and 1.2 these will allow deco on a set point of 1.4 for various mixes Tom Mount At 05:44 PM 6/26/96 +0000, you wrote: >T.J. > >On Wed, 26 Jun 1996 tjm@ea*.ne* wrote: > >> Besides, I will have to modify mine for tech-stuff - >> computer, O.C. bailout, gas switches, etc... Will drive the cost up >> considerably. > >The issue of a computer is an interesting one. All the computers, that >this slack-jawed "prosumer" has seen, use variations of the standard >algorithms where the inspired concentration of gas is constant and the >partial pressure of the gas varies. To get the max out of your CCR, you >need a computer that takes into account the variation throughout the >dive of your FiN2 as well as depth. > >Now the Pg = Fg x depth equation would indicate that all you need to do is >substitute the computer algorithm. But the laws of physics, while constant >sometimes have hidden variables in physiologic systems. What if the >absorption of nitrogen is dependent not only on the FiN2, but also on the >ratio of FiN2/FiO2? As the CCR varies the FiO2, this ratio will change. >e.g., you want to keep your pPO2 at about 1.2 At 50 fsw your >FiO2:FiN2 is 48:52, at 100 fsw the ratio is 30:70, about half. Why do I >think this might make a difference? Murphy's Law of Medicine and the fact >that the solubilities of the two gasses (O2 and N2) are not the same. >Basically I'm asking if all that matters is the pPN2 or if the relative >concentrations of other gasses, have an effect on the absorption of >nitrogen (..like the oxygen window effect). > >> Let's do get a couple (of CCRs) and go diving! > >Absolutely, but before I plunge to depths where time at decompression >stops is important, I would like to be sure that the assumptions I make >about nitrogen absorption when the FiN2 is constant remain true when it >varies. > >I'm hoping that some of the mavens on the net can show this bu(r)bbling >diver the light. > >Peter > > >-- >Send mail for the `techdiver' mailing list to `techdiver@terra.net'. >Send subscription/archive requests to `techdiver-request@terra.net'. >
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