Effect of slow compartments size in relation to NDL and DECO

[JoshuaHeard]

I didn't read all previous pages in this thread, so i don't know if the question has been answered, but here is my response:

First, the tissue compartments in the deco algorithms are theoretical, they do not correspond to actual tissues like fat or muscle.

Second, the on-gassing and off-gassing describe the rate of absorption and diffusion in the gradient of the partial pressures of gasses. The rate and the partial pressure are both percents of the amount of gas in the tissue, so the absolute amount makes no difference. A 200 lb man and a 300 lb man will have the same rate.

What does make a difference is the relative differences in metabolism between people. So, a person who is in good shape with a high metabolism will move gasses faster than someone out of shape. The out of shape person will take longer to move gasses and to recover from a dive.

 

[HershiGles]

So, for real no chance to quantify it?Sad.Gonna contine search solutions.

Unfortunately yes. I also tried to find solutions, and it did not work out.
If yes, leave a message here.

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[narke]

I didn't read all previous pages in this thread

Well then you are missing out on a lot of fun and facts! ;-)

 

[narke]

The rate and the partial pressure are both percents of the amount of gas in the tissue, so the absolute amount makes no difference. A 200 lb man and a 300 lb man will have the same rate.

Hi, welcome,

yes but there is a caveat.

The way the rate is behaving in the model is such that the rate (of change) is equal to a constant (the Half Time) multiplied by the difference in the concentrations between tissue and ambient.

We are saying, or asking ourselves: should or could the constant be a function instead?
A relationship taking account the size of the compartment, or even another dimension. To extend duration of the dive and minimize the resulting possible damage?
In two different individuals the whatever the model is modeling there will be differences in things that equate to different size, temperature, volume, quantity held, distribution, surface area, distance...all the dimensions that we need to consider to satisfy Fick's and Henry's laws.

After all that is what Workaman and Bühlman did to Haldane, they threw a function at his constants.

Would we get safer dives for all and perhaps along with better tailored durations, depths and deco?

In the end we all have the same ambitions, to get the most from our dives in the safest way.

 

[narke]

So, presently, simplified models are used, where set M-values are applied to each compartment, and individual differences are accounted for through an overall safety factor (GF).

I dive with GFs, I am thankful for them. They are rounding corners on my envelope. I want to push the envelope. I challenge the model.

 

[dmaziuk]

We are saying, or asking ourselves: should or could the constant be a function instead?

As I understand it, bubble models do (should) use a function. A function based on "bubble" properties, not the compartment's properties, but a function nonetheless.

Personally, I would also like to see adjustments for near-saturation points because IME numeric approximations tend to get less accurate near flex points. But I also believe in keeping it simple stupid, and a fugde function based on several orthogonal sets of parameters sounds like an opposite of that.