Schreiner equation - calculating variable acent decent.

Timo_denmark · 27th September 2011, 19:14

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

Timo_denmark · 28th September 2011, 10:17

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?

aainslie · 30th September 2011, 23:50

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

Timo_denmark · 1st October 2011, 06:06

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?

27th September 2011, 19:14	#1 (permalink)
Timo_denmark RBW Member Join Date: Apr 2010 Location: DENMARK Posts: 5	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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28th September 2011, 10:17	#2 (permalink)
Timo_denmark RBW Member Join Date: Apr 2010 Location: DENMARK Posts: 5	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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30th September 2011, 23:50	#3 (permalink)
aainslie So Cal Tech Diver Join Date: Apr 2006 Location: LA Posts: 1,015	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 "I damajed my perfials wunce" - nailer99
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1st October 2011, 06:06	#4 (permalink)
Timo_denmark RBW Member Join Date: Apr 2010 Location: DENMARK Posts: 5	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?
(Offline)

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