mmmm very interesting !!
so another question !!!!

Do i set the program to calculate 3m stops and i do them at 6m
or do i set the program to last stop 6m ???

Because there is some signifigant diference on time !!!

Manos Manoli
Limassol - Cyprus

Viktor Sajn wrote:

> Hi Ian!
>
> The problem is really complicated if you look at,
> from not to the best side. I will not write about
> the (right but not the new one) diffusion decco
> model, but about benefits of breathing 100% O2 at
> 6m (20') rather than 3m (10').
>
> If somebody does a decompression dive (long) at
> the end of dive he wants to make safety but as
> short as possible decco. If one in procedure of
> decco is low on nitrogen and helium and another
> inert gases so that his (calculated) ceiling is 6m
> (20') he will accent to 6m (20')a switch to max
> inert offgasing of course with 100% O2. Logical?
> Ok, after some decco time the concentrations of
> inert gasses are so low that he can continue his
> 100% O2 decco on 3m (10') with less or more the
> same speed off offgasing (there are some
> difference connected with PPO2).
>
> BUT IF HE IS CLEVER HE WILL NOT DO THAT. HE WILL
> STAY ON 6m (20') TILL THE END OF DECCO.
>
> Why? Simple, is he convinced that after part of
> decco his ceiling is 3m (10')? So it is calculated
> by program, but sensitivity to decco of the same
> diver can be much different regardless to many
> factors. Does the program know how you feeling or
> are you dehydrated ..? NO! So if his decco is
> critical regardless to shape of the diver, maybe
> he will get bent.
>
> So if he stays at 6m (20') he lower risk of
> getting bent not the breaking eventual deeper
> ceiling and has less or more the same speed of
> offgasing. This meaning if you want to do the
> decco with the same risk you can short it with not
> going to 3m (10')!
>
> If you look at this explanation little wider, you
> can see that this philosophy is nothing that
> application of DEEP DECCO STOPS. Why to accent to
> 3m (10') to irritate possibilities of bubble
> growing? Because of toxity benefit of 1.3 against
> 1.6 PP02?
>
> What is conclusion of this email?
>
> DOING DECCO ON 100% 02 ON 6m (20') IS THE RIGHT
> WAY.
>
> Viktor
>
> -----Original Message-----
> From: Ian Puleston [mailto:DiverIan@pa*.ne*]
> Sent: 4. januar 2001 3:39
> To: techdiver@aquanaut.com
> Subject: ppO2 and off-gassing N2
>
> Reading the stuff previously posted on the Oxygen
> Window - especially Bill
> Wolk's postings which are very helpful - it almost
> all makes sense, except
> that I can't quite understand why the high ppO2 in
> the blood helps the
> Nitrogen come out of the cells. I understand the
> advantages of 100% O2 over
> 80/20, but can't fully see why breathing 100% O2
> at 20' is better than
> breathing 100% O2 at 10'. I accept that it has
> proven to be better, but
> would like to understand the theory as to why.
>
> Bill Wolk defined the Oxygen Window as used in
> diving theory as "the
> difference between the concentration of inert gas
> dissolved in tissue vs.
> the concentration of oxygen and inert gas in
> arterial blood". Breathing an
> elevated ppO2 forces extra O2 to dissolve into the
> blood plasma, in addition
> to that normally carried bound to Hemoglobin. So
> far I'm with the program.
>
> But what I can't see is how this additional O2
> affects the N2 coming out of
> the tissues. When there is no N2 in the arterial
> blood anyway, why does
> forcing additional O2 into it make a difference?
>
> According to Henry's law the amount of Nitrogen
> that will dissolve into the
> blood is affected only by the partial pressure of
> the Nitrogen itself, so
> increasing the ppO2 will have no effect on that. A
> previous posting (which I
> can't find now, but I don't think anyone argued
> against it) indicated that
> increased ppO2 will tend to block the Nitrogen
> molecules from coming out of
> the cells by osmosis.
>
> The only beneficial effect of the additional O2
> that I can see is that
> (again from a previous Bill Wolk posting) "the
> additional osmotic pressure
> forces O2 into the surrounding tissue, which has
> the effect of oxygenating
> tissue and reducing swelling and clotting --
> essentially, healing the
> cellular damage caused by deco diving". Is that
> the only benefit of the
> higher ppO2, or is there something other way in
> which it aids off-gassing
> N2?
>
> Anyone care to explain?
> Ian
>
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