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Whales, seals, and other marine mammals seem to do alright in the chill waters of the arctic seas, so the US Navy is developing a type of "artificial blubber" to allow divers to work in freezing conditions for hours on end. Sponsored by the Office of Naval Research (ONR), the collaboration between MIT and George Mason University uses an off-the-shelf wetsuit permeated with inert gases to triple a diver's resistance against the threat of hypothermia.
[...] The modification involves replacing the air trapped in the neoprene foam that provides heat insulation with heavy, inert gases, such as xenon and krypton, which make the neoprene act like fat-concentrating blubber. This is done by putting an ordinary neoprene suit into a bespoke pressure tank the size of a beer keg and pumping in the inert gases. After several hours, the gas permeates the suit, forcing the air out.
According to ONR, this makes the suit effective at 10° (50° C)[sic see note] for hours instead of minutes. The treatment isn't permanent as the gases leak out over 20 hours, but the team points out that this is much longer than the time divers spend in the water.
Why not recruit divers with more blubber?
[Note: This conversion error appeared in the original story; it should have read: 10°C (50° F). Story updated 20180907_011649 UTC --martyb]
(Score: 5, Informative) by Goghit on Friday September 07 2018, @05:13AM (6 children)
So much garbled nonsense in this story it's hard to know where to begin. It reads a bit like stories about that Korean dude's vaporware artificial gill.
Noble gas foamed neoprene has been an idea that's been kicking around for a while. The thing is, any gas space will compress under pressure; at 10 metres it doesn't matter if you foamed with air, straight nitrogen, or argon, the bubbles have collapsed to half their surface size and your wetsuit material is now half as thick as it was on the surface. By the time you get to 40 metres your suit is starting to feel like a bit of parchment. Under these conditions a very thin layer of argon and neoprene is only slightly more effective than a very thin layer of air and neoprene at keeping you warm. I will leave it as an exercise for someone who gives more of a shit than I do what the comparative thermal co-efficients would be between air and argon in a piece of neoprene compressed from 7 to 1.5 mm thickness.
Nobody but amateurs, crazy people, and maybe underfunded grad students use wetsuits for cold water work. Yes, you can work in one, but you will end up freezing your cajones off and hypothermic technicians don't collect good data or make good decisions. Professionals use dry suits. There are dry suits made of of neoprene but those are still subject to the same compression problem described above. You are relying on the thermal underwear and the gas layer you maintain between you and the outer shell of the suit, not the thermal characteristics of the outer shell unless you're very shallow.
Some of the best cold water dry suits are membrane suits. The outer shell is a laminate of (unfoamed) synthetic rubber and fabric, tough as nails but relatively thin and providing very little thermal protection by itself - you need a thermal undersuit and gas between you and the suit shell. They sound cumbersome but they are more flexible and very much warmer to work in than a wetsuit.
This line in particular sets off my bullshit detectors: "According to ONR, this makes the suit effective at 10° (50° C)[sic see note] for hours instead of minutes." 10° is not particularly cold, a conditioned diver can spend all morning in an uncompressed (i.e.: on the surface) wetsuit and even work up a sweat if heavy exercise is involved. "Minutes" is the length of time I last when I push the start of swimming season and enter 10° water in just my swimming trunks.
Maybe this is something for spearfishers in the Mediterranean and the popular press is just doing its usual thing with a science topic. It would interesting to see actual performance data at depth for this material but jeez, kids, the future of Arctic diving is not in wetsuits unless global warming far exceeds Gore et al's worst nightmares.
(Score: 2) by jelizondo on Friday September 07 2018, @07:11AM (4 children)
Who cares about freezing chest drawers [google.com] while diving? You should worry about your cojones, which is a different thing.
Say balls, nuts or testicles if you can't spell a foreign word.
(Score: 2) by PiMuNu on Friday September 07 2018, @11:30AM (3 children)
> Say balls, nuts or testicles if you can't spell a foreign word.
It's an interesting question; cojones is a euphemism, but I wonder if there are _degrees_ of euphemism. Balls, nuts, testicles may be too abrupt for the context...
(Score: 2) by theluggage on Friday September 07 2018, @02:55PM
I thought "freezing your balls off" was a corruption of "cold enough to freeze the balls off a brass monkey" - a totally innocent nautical phrase referring to the effect of differential thermal contraction on the brass racks used to store iron cannonballs on old warships. What else could it mean? (see also: "cockup").
(Score: 2) by jelizondo on Friday September 07 2018, @03:36PM
I was making fun of GP, he wrote "cajones" not "cojones", both being Spanish words with very different meanings.
😁
(Score: 0) by Anonymous Coward on Friday September 07 2018, @05:23PM
I would say that it is obvious that there ARE degrees of euphemism.
(Score: 2) by pvanhoof on Friday September 07 2018, @06:43PM
PADI Rescue Diver (1409EW7988) here.
An example of such a neophrene drysuites can be found here [scubapro.com]. Noting that the neophrene (or whatever skin is used for the drysuit) is mostly protection against sharp objects (less dangerous) and angry fish protecting their eggs (some of them far more dangerous), and the possibility of a tight fit around your body while it's still a drysuit.
For warmth, as you point out, the air between your body and the drysuit is probably much more important. With a tight-fit neophrene drysuit, wearing a lot under the drysuit is of course difficult (it's a tight fit around your body). The fact that you can't easily wear a lot of (normal) clothes in a neophrene drysuit is why not all drysuit divers like it. It's not comfortable and can even be dangerous (not enough blood going through your vains will BTW make your body cold, too).
You can blow in more air if 40m deep the existing air gets compressed. You'll waste air from the scuba tank doing so a lot, though. So most divers try to not change too much to the air in their drysuit once the dive started. When they come back to the surface, they usually let a bit of air out of the drysuit (~ continuously while going up). Because air that has a certain volume at 40m deep will have a much later volume at 5m deep. Meaning you'd start going to the surface faster and faster (you might even fly a bit out of the water, as a blown up balloon). Going so fast from 40m to surface will probably also kill you. This is also why drysuit divers prefer not to blow air into the drysuit at 40m deep: you'll blow in compressed air. When going up to the surface, the drysuit will grow in volume a lot. You'll look like Michelin Man [wikipedia.org]. It's not easy to swim back to the boat that way, either.
Of course will most neck-seals of most drysuits let air escape through the seal if things get blown up too much.. But by the time that's happening you are going to the surface way way too fast.