Dr Deco
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:14: Hello Readers:
Models that are Not Models
Again, we have this problem of models - which decompression calculations are not. They are more akin to book keeping and profit and loss records. The sales price minus the materials and labor cost should equal the profit [simplified model]. If it does not, it indicates that the account has not included some factors or that pilferage is occurring.
Using the accounting figures, you would not be able to determine how an automobile [or Coca-Cola] is actually made. It does not have that degree of detail. Diving algorithms likewise are profit and loss [simplified] for gas loading and unloading and are only correct for a small fraction of the diver demographic. It would be nice if the models were correct, but we know that they are not.
Haldane Limited Supersaturation Model
This concept forms the underlying basis for the algorithms in use today [an exception is the RGBM]. It assumes that free nitrogen in the form of gas bubbles does not occur - ever. When dissolved nitrogen goes into bubbles as free gas, it is lost to the accounting system; it is like pilferage since the actual nitrogen elimination is actually reduced from tissue.
We know that microbubbles are present in tissues. Any system that contains nuclei will bubble to some degree when subjected to a reduced pressure. This is true of everything from pastry dough to volcanic lava. Only in decompression physiology was this concept poorly recognized [until about 1990]. Diving adhered to spontaneous nucleation.
There are laboratory studies that indicate a strong dependence on individual physiological factor and bubble formation and DCS. Unfortunately, these studies deal with depressurization to altitude. [Space work is better funded than diving research; e.g., I worked for NASA in the Medical Sciences Division].
What Is Wrong?
A few problems, e.g., bubble formation, I briefly discussed earlier in this post. That real problem in repetitive diving and fly-dive scenarios is what is referred to as chaotic, non-linear systems. I shall speak about that shortly in another forum on Scuba Board.
Models that are Not Models
Again, we have this problem of models - which decompression calculations are not. They are more akin to book keeping and profit and loss records. The sales price minus the materials and labor cost should equal the profit [simplified model]. If it does not, it indicates that the account has not included some factors or that pilferage is occurring.
Using the accounting figures, you would not be able to determine how an automobile [or Coca-Cola] is actually made. It does not have that degree of detail. Diving algorithms likewise are profit and loss [simplified] for gas loading and unloading and are only correct for a small fraction of the diver demographic. It would be nice if the models were correct, but we know that they are not.
Haldane Limited Supersaturation Model
This concept forms the underlying basis for the algorithms in use today [an exception is the RGBM]. It assumes that free nitrogen in the form of gas bubbles does not occur - ever. When dissolved nitrogen goes into bubbles as free gas, it is lost to the accounting system; it is like pilferage since the actual nitrogen elimination is actually reduced from tissue.
We know that microbubbles are present in tissues. Any system that contains nuclei will bubble to some degree when subjected to a reduced pressure. This is true of everything from pastry dough to volcanic lava. Only in decompression physiology was this concept poorly recognized [until about 1990]. Diving adhered to spontaneous nucleation.
There are laboratory studies that indicate a strong dependence on individual physiological factor and bubble formation and DCS. Unfortunately, these studies deal with depressurization to altitude. [Space work is better funded than diving research; e.g., I worked for NASA in the Medical Sciences Division].
What Is Wrong?
A few problems, e.g., bubble formation, I briefly discussed earlier in this post. That real problem in repetitive diving and fly-dive scenarios is what is referred to as chaotic, non-linear systems. I shall speak about that shortly in another forum on Scuba Board.
