Dr Deco
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Hello Readers:
Background: Bubble Models versus Haldane Models
While Haldane (Limited supersaturation) models worked fairly well, there was always the nagging problem that they were not physically real. That is, the formation of a gas bubble from dissolved nitrogen at such a low supersaturation was really not possible. Surface tension would not allow it. Therefore any table based on this idea was suspect right from the beginning.
The incorporation of preformed gas bubbles did not find its way into diving until recently, however. Brian Hills spoke about remaining deeper than the Haldane model suggested, but he never garnered much support among table designers the old guard. A true nuclei-based model was developed in about 1975 by Michael Gernhardt. (He tells me that this was actually when he first assembled his concept.) It was about this time at the gel bubble experiments of Michael Strauss was being published. The Hawaii group (mainly physicists) did much to advance the nuclei concept, even if the physical basis for the model for nuclei generation was incorrect (bubbles stuck on solids in very solid gels).
The bubble models work well because the divers do not generate new nuclei during the dive. This is my supposition and currently there is not any proof of this. The major factor for being suspicious about nuclei generation in the slow rate with which divers must be decompressed when they are in a decompression chamber and free to move about. They very often develop DCS problems in the legs.
Dr Deco :doctor:
Readers, please note the next class in Decompression Physiology :umnik:
http://wrigley.usc.edu/hyperbaric/advdeco.htm
Background: Bubble Models versus Haldane Models
While Haldane (Limited supersaturation) models worked fairly well, there was always the nagging problem that they were not physically real. That is, the formation of a gas bubble from dissolved nitrogen at such a low supersaturation was really not possible. Surface tension would not allow it. Therefore any table based on this idea was suspect right from the beginning.
The incorporation of preformed gas bubbles did not find its way into diving until recently, however. Brian Hills spoke about remaining deeper than the Haldane model suggested, but he never garnered much support among table designers the old guard. A true nuclei-based model was developed in about 1975 by Michael Gernhardt. (He tells me that this was actually when he first assembled his concept.) It was about this time at the gel bubble experiments of Michael Strauss was being published. The Hawaii group (mainly physicists) did much to advance the nuclei concept, even if the physical basis for the model for nuclei generation was incorrect (bubbles stuck on solids in very solid gels).
The bubble models work well because the divers do not generate new nuclei during the dive. This is my supposition and currently there is not any proof of this. The major factor for being suspicious about nuclei generation in the slow rate with which divers must be decompressed when they are in a decompression chamber and free to move about. They very often develop DCS problems in the legs.
Dr Deco :doctor:
Readers, please note the next class in Decompression Physiology :umnik:
http://wrigley.usc.edu/hyperbaric/advdeco.htm
