NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sperm whale buoyancy.
From: Henry Halboth
Date: 2007 Mar 25, 21:48 -0500
From: Henry Halboth
Date: 2007 Mar 25, 21:48 -0500
To all interested, Perhaps we should clarify just what the bends and nitrogen narcosis are, and how they separately affect the diver. Many years ago, Dr. Haldane, an English physician, established that if the human body contained dissolved gas at a pressure greater than twice the outside pressure, bubbles would form. It is the formation of these bubbles and their entrapment in the body tissues that cause the so called bends, or more technically "decompression sickness". The most practical method of bringing a diver to the surface, from depths of 60 feet and grteater, in order to prevent the formation of bubbles was originally "staged decompression", or stopping the ascent at regular intervals for a time sufficient to allow gas to escape from the blood stream without the formation of bubbles. Dr. Haldane's work lead to the first successful decompression tables to the benefit of divers and caisson workers generally, and more recent developments, i.e., surface decompression, mixed gases, etc., have lead to modifications that there is no point in discussing hear. The pathophysiology of the "bends" is based on the breathing of gases under pressure and their subsequent too rapid release, leading to the formation of systemic bubbles which seem to concentrate primarily in the joints, and which may also lead to massive pulmonary embolism and rapid demise. Nitrogen narcosis is an intoxication occasioned by the breathing of nitrogen and argon, both constuients of atmospheric air, at the increased partial pressure encountered when atmospheric air is compressed at great depths. It affects the sensory perception and muscular coordination of a diver working at great depths on compressed air. The solution to this problem was found in the employment of helium and other mixed gases in deep diving operations. Just as some people can consume greater amounts of alcoholic beverages than others without ill effect, the affects of nitrogen and argon are not as predictable as the onset of the bends. George's comments regarding the compressibility of the body are most probably true, however, to the best of my knowledge, not presently of practical consequence or experimentally quantified. Although of considerable interest generally, and subject to considerable elaboration, my comments are outside the scope of this List and I have chosen to go no further. Henry ----- Original Message ----- From: "Michael Dorl"To: Sent: Sunday, March 25, 2007 3:00 PM Subject: [NavList 2478] Re: Sperm whale buoyancy. > > My uninformed two cents worth... > > I wonder if the bends and nitrogen narcosis for divers with large air > supplies (either hard hat or aqua lung) are not caused by not caused by the > large volume of air they are exposed to under high pressure over > time. Stated another way, if all of the air in an animals lungs (one > volume) were to go into solution in the blood would that be enough to cause > narcosis and bends? Or would it require many lungs full? > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---