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Thread: Schreiner equation - calculating variable acent decent.

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    RBW Member Timo_denmark is an unknown quantity at this point Timo_denmark's Avatar
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    Schreiner equation - calculating variable acent decent.

    Hi there - i am calculating a few dives on my pc - but i cant seem to find any tables where i can check if everything works as it should. Can any of you check if the following dive is calculated right.

    Ill use this model.

    P = P(alveole) + R(t - 1/k) - [P(alveole) - Po - (R/k)]e^-kt

    here is a few compartments (i guess if one is wrong, everything is wrong)


    Halftime 4 tissue 1.46337 Max: 1.980198019802
    Halftime 8 tissue 1.5510773761029 Max: 1.5350452140824xx

    Halftime 635 tissue 0.75807762802302 Max: 1.0359299772754

    Last but not least.

    I would like to calculate the tisssu satturation with variable (relative or linaer) acent/decent speed - anybody knows how to change

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    RBW Member Timo_denmark is an unknown quantity at this point Timo_denmark's Avatar
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    Re: Schreiner equation - calculating variable acent decent.

    Woops forgot some stuff... (girlfriend came home, laptop died)

    Dive profile : 30 meters stay 10 minuttes. and then a 10 decent. RQ=0.9 like US-navy

    From ambient tissue load.

    Result After 20 min at 30 meters

    Halftime 4 tissueload =3.0160038648437
    Halftime 30 tissueload =1.6041570801843
    Halftime 635 tissueload =0.782473752927

    Result after 10 min ascent to 0 meters from 30 meters (20min stay)

    Halftime 4 tissueload = 1.846901486898
    Halftime 30 tissueload = 1.6596768843148
    Halftime 635 tissueload = 0.79478203640184

    Maximumtissueload surface.
    t4 - Max: 1.980198019802
    t30 Max: 1.2159151412524
    t635 Max: 1.0359299772754

    wich means that in compartments wit a halftime of 5 - 100 minutes i have to much N2 surfaceing (even more if the acent is quicker)

    Anyone of you can se what seems wrong?

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    Re: Schreiner equation - calculating variable acent decent.

    Seems fine until the 9th decimal place then the errors creep in. Perhaps upgrade your floating point module?
    Andrew Ainslie

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    RBW Member Timo_denmark is an unknown quantity at this point Timo_denmark's Avatar
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    Re: Schreiner equation - calculating variable acent decent.

    Well that is a problem! Thanks for pointing that out Andrew. I would like it to be very precise - i have not figured out java yet, so i did used PHP to calculate the satturation, and it seems that there is a limit to the precision. Anyone of you have a piece of java code(thats more precise) that i can modify?

    Also if possible i would like be able to calculate a dive profile thats changes decent speed on the way down - anybody figured out how to do that?

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