Artificial gills (human)

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Contents 1 Like-A-Fish 2 References 3 See also 4 External links

Artificial gills are devices that exist in science fiction, and being developed in reality, to extract oxygen dissolved in water, thus allowing humans to survive underwater.

It is generally thought that they would be unwieldy and bulky, because of the massive amount of water that would have to be processed to extract enough oxygen to supply an active diver, as an alternative to a scuba set. However, Like-A-Fish is an ongoing attempt to develop such a system in the real world.

As sea water contains 7 ppm oxygen, 1,000,000 kg (1,000 tonnes) of sea water holds 7 kg (1,000 short tons holds 14 lb) of O₂, the equivalent of 5,350 litres (1,400 U.S. gallons) of oxygen gas at atmospheric pressure.

An average diver with a fully closed-circuit rebreather needs 1 litre (roughly 1 quart) of oxygen per minute. As a result, at least 192 litres (51 gallons) of sea water per minute, or 3.2 liters (3.5 quarts) each second, would have to be passed through the system, and this system would not work in anoxic water.

Natural gills work because nearly all animals with gills are cold-blooded and so need much less oxygen than a warm-blooded animal the same size^[1].

[edit] Like-A-Fish

Like-A-Fish Technologies is an Israeli business, founded by Alan Bodner in 2001, that is developing a human artificial gill system; they have developed a prototype.^[2] Like-A-Fish's technology uses a centrifuge causing lower pressure at the center, where dissolved air comes out of the water.^[3]

The key issue remaining is battery life. Currently a one kilo battery would only last for one hour,^[2] whereas a regular scuba tank can last longer (depending on depth). The biggest possibilities lie in underwater habitats, which have access to electricity, but need constant refilling of air tanks. Additional possible uses include systems for scuba divers and submarines, among others.

Like-A-Fish currently holds patents in Europe for its system.^[4][5]

[edit] References

1. ^ Why don't people have gills?
2. ^ ^{a b} Lakshmi Sandhana. "Inventor develops 'artificial gills'", BBC News, 2006-01-31. Retrieved on 2007-09-14. 
3. ^ Iddo Genuth, Tomer Yaffe. "Like A Fish - Revolutionary Underwater Breathing System", IsraCast, 2005-12-14. Retrieved on 2007-09-14. 
4. ^ Open-circuit Self-contained Underwater Breathing Apparatus (WO0240343). European Patent Office. Retrieved on 2007-09-18.
5. ^ Open-circuit Self-contained Underwater Breathing Apparatus (EP1343683). European Patent Office. Retrieved on 2007-09-18.

[edit] See also

• Henry's Law
• BioSub
• Scuba set

[edit] External links

• New Scientist article - history of attempts to develop artificial gills and the principles and problems involved (subscription required)
• BBC Article A BBC article about the Like-A-Fish system
• Bill Christensen (2005). Breathe Like A Fish Thanks To Alan Bodner. Science Fiction in the News. Technovelgy.com. Retrieved on 2007-09-14.
• www.likeafish.biz Official website
• 'Like A Fish' Underwater Breathing System: Artificial Gills for U.S. Navy SEALs?
• Specific publication reference dates from an unusual source