First Principals Article or Text on Dive Modeling

[LAJim]

I am looking for a very specific sort of article or textbook, hopefully one that is readily available - but I'd rather have the right one than an easily located one.

I am a physical science professor at a major research university and DIR-F provisional. I make over 100 dives per year currently. I have extensive professional experience with computer modeing including theoretical calculations of molecular properties. As such I normally have a nuanced view of the relationships between the actual chemical or physical process, the model chemistry or physics used to represent reality in an approximate way, and the numeric strategies that might be use to compute a result on top of that model physics.

Recently I have become annoyed at myself because I don't understand the assumptions and rationale underlying how deco software or dive computer algorithms actually operate - and I am looking for a single coherent presentation - at a very high level. This should ideally treat modeling of the body (perhaps as a series of compartments) with kinetic and equilibrium properties, then focus on, I suppose, an approximate description of bubble nucleation and growth to build up a complete model, followed by suitable approximations and a master equation for an observable such as bubble size and/or density as a function of gas loading over the course of a variable profile.

This might not exist. If it does I'd appreciate a reference.

Jim

 

[knotical]

You might try various offerings by Bruce Wienke, including:
Basic Decompression Theory and Application.

 

[UWSojourner]

Wienke's "Technical Diving in Depth" may also help.

There is also publicly available source code for the VPM and Gradient Factor decompression algorithms.

These are good if you haven't been to them.

http://www.decompression.org/baker/home.htm

http://www.decompression.org/maiken/home.htm

http://rubicon-foundation.org/

Let us all know if you do come up with a good EOS for bubbles in a diver. I'd love to hear about it. To my knowledge it doesn't exist in the VPM and, although Wienke claims an EOS for RGBM, its not publically available.

 

[LAJim]

Nope - none of this is what I'm looking for - it should look like a graduate text in chemical engineering.

Jim

 

[UWSojourner]

... it should look like a graduate text in chemical engineering.

Have you tried searching google for "graduate texts in chemical engineering". Sorry, couldn't resist.

Actually, we need more people like you (i.e. much smarter than me) trying to get to the bottom of the deco situation. You may want to contact Wienke directly. I think he has a profile on www.thedecostop.com. Maybe here as well. My best wishes in your search.

 

[LAJim]

Have you tried searching google for "graduate texts in chemical engineering".

Many of them are on my bookshelf actually.

I think an obvious thing for me to do is call the Naval Research Laboratory ...


No time today. But if there is a someone on this board from NRL or a similar organization please PM with contact information for someone you think I should talk to.

Jim

 

[Gene_Hobbs]

Recently I have become annoyed at myself because I don't understand the assumptions and rationale underlying how deco software or dive computer algorithms actually operate - and I am looking for a single coherent presentation - at a very high level. This should ideally treat modeling of the body (perhaps as a series of compartments) with kinetic and equilibrium properties, then focus on, I suppose, an approximate description of bubble nucleation and growth to build up a complete model, followed by suitable approximations and a master equation for an observable such as bubble size and/or density as a function of gas loading over the course of a variable profile.

This might not exist. If it does I'd appreciate a reference.

This is a VERY broad request as NO one book covers it all... I would think the Wienke books already mentioned would be of interest but it is hard to guess.

As for not finding what you want in the Rubicon Research Repository, how about I throw out a few papers and you tell what you want more or less of... (I am sorry the system is so small and that we only have NEDU tech reports through 1970 covered well so far.)

These discuss the development of the USN VVAL-18 algorithm by Ed Thalmann:
The U.S. Navy decompression computer.
Butler and Southerland 2001
RRR ID: 2364, PubMed ID: 12153150

Computer Algorithms Used in Computing the Mk 15/16 Constant 0.7 ATA Oxygen Partial Pressure Decompression Tables.
Thalmann 1983
RRR ID: 3294, DoD ID: ADA125064, NEDU: NEDU-1-83

If Probabilistic Models are your interest, try this 11 volume collection (If nothing else, the references from these should give some direction):
Statistically Based Decompression Tables. I. Analysis of Standard Air Dives: 1950-1970.
RRR ID: 3402
Statistically Based Decompression Tables. II. Equal Risk Air Diving Decompression Schedules.
RRR ID: 3403
Statistically Based Decompression Tables. 3. Comparative Risk Using U.S. Navy, British, and Canadian Standard Air Schedules.
RRR ID: 3404
Statistically Based Decompression Tables IV: Extension to Air and N2-02 Saturation Decompression.
RRR ID: 3405
Statistically Based Decompression Tables 5: Haldane-Vann Models for Air Diving.
RRR ID: 3406
Statistically-Based Decompression Tables. 6. Repeat Dives on Oxygen/ Nitrogen Mixes
RRR ID: 3407
Statistically Based Decompression Tables. 7. Selection and Treatment of Primary Air and N2 - O2 Data.
RRR ID: 3408
Statistically Based Decompression Tables 8: Linear-Exponential Kinetics.
RRR ID: 3409
Statistically Based Decompression Tables IX: Probabilistic Models of the Role of Oxygen in Human Decompression Sickness.
RRR ID: 3410
Statistically Based Decompression Tables X: Real-Time Decompression Algorithm Using a Probabilistic Model.
RRR ID: 3411
Statistically Based Decompression Tables XI: Manned Validation of the LE Probabilistic Model for Air and Nitrogen-Oxygen Diving.
RRR ID: 3412

There are also a couple of abstracts by Alf Brubakk that could be worth looking into. They are doing some of this work with ScubaPro:
A MODEL PREDICTIVE FRAMEWORK FOR DYNAMIC CALCULATION OF OPTIMAL DECOMPRESSION PROFILES.
RRR ID: 1577 ---note: this is an abstract so NO paper available. The paper reference from the abstract is RRR ID: 3898

PARAMETER ESTIMATION OF THE COPERNICUS BUBBLE MODEL USING HUMAN DOPPLER DATA.
RRR ID: 3621 ---note: this is an abstract so NO paper available.

But if there is a someone on this board from NRL or a similar organization please PM with contact information for someone you think I should talk to.

If I were planning to call someone in the US, I would start with Wayne Gerth at NEDU and Dick Vann at Duke. Dick can be more responsive most of the time and currently has some work going with the Engineering Department at Duke (this work is in collaboration with NEDU - Wayne).

AN OBJECT-ORIENTED SYSTEM FOR OPTIMIZING PROBABALISTIC DECOMPRESSION MODELS TO EMPIRICAL DECOMPRESSION DATA.
RRR ID: 3756 ---note: this is an abstract so NO paper available.

For other papers, read through my talk on Diving Medical Literature and you should be able to find MUCH more than what we have in our database so far.

There is another GREAT paper in press now but I can't talk about it yet. It is a nice new look at these models.

Is this a good start?

 

[Gene_Hobbs]

Sorry, forgot... I would also get my hands on a copy of:
Bühlmann, A. A. (Albert Alois), 1923- Decompression-decompression sickness / A.A. Bühlmann. Berlin ; New York : Springer-Verlag, 1984.

I have sold three copies of this in the last six months to support more work on the repository. If I find another, I'll let you know. In the mean time, as a University Prof you can get this book on loan from the UHMS collection at Duke.

There are also a few UHMS Workshops that may be of interest:

Barnard EEP, Harvey CA (eds). Diving Data Banks. 5th Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number WS2-15-76. Bethesda: Undersea and Hyperbaric Medical Society; 1974; 126 pages.

Berghage TE (ed). Decompression Theory. 17th Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 29WS(DT)6-25-80. Bethesda: Undersea and Hyperbaric Medical Society; 1978; 180 pages.

Schneiner HR, Hamilton RW (eds). Validation of Decompression Tables. 37th Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 74(VAL)1-1-88. Bethesda: Undersea and Hyperbaric Medical Society; 1989; 167 pages.

Vann RD (ed). The Physiological Basis of Decompression. 38th Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 75(Phys)6-1-89. Bethesda: Undersea and Hyperbaric Medical Society; 1989; 437 pages.

Hamilton RW (ed). "Effectiveness of Dive Computers in Repetitive Diving". 44rd Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 81(DC)6-1-94. Bethesda: Undersea and Hyperbaric Medical Society; 1995; 71 pages

Weathersby PK, Gerth WA (eds). Survival Analysis & Maximum Likelihood Techniques as Applied to Physiological Model. 51st Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number WD650. Kensington: Undersea and Hyperbaric Medical Society; 2002; 176 pages.

 

[LAJim]

Gene:

You look like a great source. I am going to ILL the Buhlmann book as a starting point. I've been thinking about my objectives here and in the medium-term (6 months or so) I'd like to be able to put together a 1 or 2 hour power-point lecture that would let me explain deco theory (first principles and empirical models) to technically oriented (both senses of the word) groups of divers in SoCal. Some of us out here, especially in the DIR group, are trying to get a better feel for the engineering and science behind our diving and I'm probably the guy to get this organized locally.

If any of the reports you cited are available as downloads let me know what I need to do get access to them.

Thanks,

Jim

 

[TSandM]

You do that, Jim, and I'd be tempted to fly down to hear it