IsraCast: Like a Fish – Revolutionary Underwater Breathing System.
Alon Bodner has developed a method of extracting the dissolved oxygen in water, the preferred choice of fish. Calculations based on a laboratory model suggests that a one-kilo lithium battery can provide enough oxygen for a one hour dive (no indication of depth).
Thanks to Hoeken and the Biomimetics listserver for this clipping...
2005/06/07 A comment from Dr. Julian Vincent suggests that certain insects are able to pull off a similar feat without centrifuges
"The physics of breathing underwater is found not only in fish but in the way in which air-breathing water bugs respire using a trapped bubble of air, and the trick is that the diffusion coefficients of nitrogen and oxygen into water are different, as are the dissolved amounts. In the Israeli system (URL) the rate of diffusion is accentuated by using a centrifuge to alter the concentrations of gas at the air/water interface, but a bug can manage with its body surface. Presumably it's a volume/surface area thing. But I see no reason why a diver shouldn't be able to wear a hairy suit which would keep a thin layer of air all over him which would then be the diffusion interface. In bugs this increases the underwater time by a factor of about 10 compared with the amount of oygen in the air to start with. It might be a useful thing for a survival suit. Read all about it by looking up Aphelocheirus in Google (can't guarantee anything, but that's one of the main insects in the story). The other buzz-word is plastron.
Years ago people were keeping hamsters underwater in bubbles made from silicon rubber membrane. Presumably Goretex would be better."
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