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Rise and Fall of the Bubble (Model) ?

Discussion in 'Ask Dr. Decompression' started by Roger Hobden, Sep 25, 2018.

  1. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    Thoes deep stop algorrithms were started about a decade ago, when the deep stop theory was in its prime.

    The NEDU study was done when the deep stop theory was going strong, and it was was designed to test to see if it was as good as everyone was saying it was. As Simon said many times, at that time deep stops were all the rage, and just about everyone believed in them--including him.
  2. Roger Hobden

    Roger Hobden Barracuda

    # of Dives: 50 - 99
    Location: Montreal
    Thanks ! Very kind of you to let me know this crucial piece of information. Much appreciated ! :)
  3. uncfnp

    uncfnp Solo Diver

    # of Dives: 500 - 999
    Location: North Carolina
    Is that the sum and total of it then? If deep stops are bad then the entire bubble model is obsolute? I admit that the theoretical models are far beyond my understanding but I thought there was more to it, ascents, repetitive dives and other nuisances that are incorporated into recreational algorithms that follow so called bubble models.
  4. Jack Hammer

    Jack Hammer Solo Diver

    Oh yeah, and BTW DD and others expected the study to to show their deeper stop profile was more efficient than their shallower stop profile. It actually showed the opposite.
    shoredivr and Bob DBF like this.
  5. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    We don't want to make the mistake of jumping to the either/or fallacy. We don't know enough to make any such judgment. It appears as if the early deep stop models were too deep for those first stops. That does not mean that a stop deeper than those in a pure dissolved gas model like Bühlmann is automatically wrong. More research needs to be done. I am personally using a 50/80 GF profile, which calls for deeper stops than does a pure dissolved gas model.
    Dan_P, Trace Malinowski and uncfnp like this.
  6. dmaziuk

    dmaziuk Orca

    You'd have to call dissolved gas models thoroughly debunked and obsolete first then: recall that dissolved gas models originally aimed to prevent bubble formation. And then doppler ultrasound came along and showed that bubbles are always present -- epic fail.
  7. dmaziuk

    dmaziuk Orca

    If he can take Fortran code and compile it into a windios gooey app, he's a way better programmer than about anyone I know.
    sigxbill likes this.
  8. tridacna

    tridacna ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: New Jersey
    print *, ‘I resemble that remark’

    Dammit. I started programming with Fortran 77 on a Univac 1106.The thought of reverse engineering that code for Windoze is terrifying.
  9. StefinSB

    StefinSB Manta Ray

    # of Dives: 200 - 499
    Location: Santa Barbara, CA
    Well, you are opening a can of worms it seems unless you think that GF’s really describe human physiology. At the end of the day what “really” happens doesn’t matter to the vast majority of us as long as we have a model that provides us with a safe envelope to dive within.
    rjack321 likes this.
  10. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    I don't think so. Buhlmann ZHL-16 is a model. Abstracted, sure, but still based on real life physiology. And sure, GFs is an ad hoc hack to introduce additional conservancy into that model.

    But my point is, if I were to choose who should implement that model into real world software, I'd really, really prefer a programmer who at least had an inkling of understanding of what the model is trying to represent rather than someone who doesn't understand crap about the real world system the model tries to represent.

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