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Several people have asked for more details concerning our implementation of
the RGBM model.
Dr. Bruce Wienke has provided the following breif description of what we are
doing.

RGBM/ABYSS Implementation

    The Reduced Gradient Bubble Model (RGBM) is a dual phase (dissolved and
free gas) algorithm for diving calculations.  Incorporating and coupling
historical Haldaniean dissolved gas transport with bubble excitation and
growth, the RGBM extends the range of computational applicability of
traditional methods.  The RGBM is correlated with diving and exposure data
on more complete physical principles.  Mucb is new in the RGBM algorithm,
and troublesome multidiving profiles with higher incidence of DCS are a
target here.  Some highlighted extensions for the ABYSS implementation of
the Buhlmann basic algorithm include:

1 -- standard Buhlmainiann nonstop time limits;
2 -- restricted repetitive exposures, particularly beyond 100 ft, based on
reduction in permissible bubble diffusion gradients within 2 hr time spans;
3 -- restricted yo-yo and spike (multiple ascents and descents) dives based
on excitation of new bubble seeds;
4 -- restricted deeper-than-previous divers based on excitation of very
small bubble seeds over 2 hr time spans:
5 -- restricted multiday diving based on adaptation and regrowth of new
bubble seeds;
6 -- smooth coalescence of bounce and saturation limit points using 32
tissue compartments;
7 -- consistent treatment of altitude diving, with proper zero point
extrapolation of limiting tensions and permissible bubble gradients (through
zero as pressure approaches zero);
8 -- algorithm linked to diving data (tests), Doppler bubble, and laboratory
micronuclei experiments;
9 -- overall, parameters in RGBM/ABYSS are conservative, but flexible and
easy to change or fit to new data.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
Christopher M. Parrett, President, Abysmal Diving Inc.
6595 Odell Place, Suite G. Boulder Colorado, USA 80301
Ph.303-530-7248, fx 303-530-2808

Makers of ABYSS, Advanced Dive Planning Software.
Available in English, French, German, Italian, Portuguese and Swedish.
Abyss, Mixed Gas, Technical Nitrox, Recreational Air.
Abyss, Technical Logbooks featuring 22 integrated databases.

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