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Nixie
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He
Helium is running out. I just saw on TV
\"Good is a product of the ethical and spiritual artistry of individuals; it cannot be mass-produced.\" --Aldous Huxley
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Maya
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has been for awhile since I think they get it from natural gas deposits
\"Prefiero ser yo extranjero en otras patrias, a serlo en la mia\"
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Nixie
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Guess we better hurry up with ITER 
Of course, who knows what'll happen with it now that Congress has cut out all US investment into it...
\"Good is a product of the ethical and spiritual artistry of individuals; it cannot be mass-produced.\" --Aldous Huxley
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MagicJigPipe
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I wonder how pure the He is that's sold at Wal-Mart? If it's good enough I'll just go buy a few of those tanks.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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The_Davster
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The He intended for use in balloon filling is diluted with oxygen so that people who inhale He to make their voice funny do not suffocate themselves.
[Edited on 1-1-2008 by The_Davster]
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MadHatter
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Helium
Primarily from natural gas wells in Texas although there are some wells in Poland. If fusion
ever makes it to the electrical grid we should be able to "synthesize" helium so-to-speak.
Price is probably going through the roof !
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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JustMe
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Not good for a key branch of radiology!!!
http://www.airproducts.com/medical/uk/hospital/products/mri/...
http://www.metrowestdailynews.com/archive/x471274468
Without liquid helium, all that technology is just a very expensive paperweight.
[Edited on by JustMe]
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microcosmicus
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Of course, helium does get made naturally as a radioactive decay
product. Given that there is a fair amount of low-level radioactivity
in most rocks (I remember once being in an accelerator facility and
having the fellow point a detector at the walls to demonstrate the
background radiation from the concrete in the walls) here is a
question for a geologist: How much helium is generated annually
by the low-level radioactive decay in rocks?
As far as synthetic helium, you could make do with a conventional
fission reactor --- make some isotopes which undergo alpha decay
and collect the helium. For instance, whacking boron-10 with a
neutron makes two helium-4 nuclei as well as a tritium, which subsequently
becomes a helium-3 nucleus. Since 19% of boron is the right isotope and
borax is in plentiful supply, I suppose this might be one way of trying
to cope with a helium crunch.
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Waffles
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I have an answer to both of your questions. Many many times more helium is generated by simple radioactive decay every year than human industry could
use. On the other hand, how much of that helium is generated in the Earth's crust or mantle below 1 or 2 miles down (a reasonable mine depth)?
Probably about 99.9999999999%.
As far as synthetic helium, helium-3 is used quite commonly in ultra-low-temp research- the problem is that it is of such low natural abundance (parts
per million) for an already rare gas that it is not possible to separate a reasonable amount from the naturally occurring. So it is in fact made
artificially, by neutron bombardment of Li, N, and B, if memory serves. Despite the relatively large demand (basically every university in the US,
certainly, as well as many companies and government projects) the price is somewhere around US$5,000,000 per kilogram  . In other words, synthetic production involving nuclear transmutation is
mindblowingly expensive, even for a product with a large demand.
| Quote: | Originally posted by microcosmicus
Of course, helium does get made naturally as a radioactive decay
product. Given that there is a fair amount of low-level radioactivity
in most rocks (I remember once being in an accelerator facility and
having the fellow point a detector at the walls to demonstrate the
background radiation from the concrete in the walls) here is a
question for a geologist: How much helium is generated annually
by the low-level radioactive decay in rocks?
As far as synthetic helium, you could make do with a conventional
fission reactor --- make some isotopes which undergo alpha decay
and collect the helium. For instance, whacking boron-10 with a
neutron makes two helium-4 nuclei as well as a tritium, which subsequently
becomes a helium-3 nucleus. Since 19% of boron is the right isotope and
borax is in plentiful supply, I suppose this might be one way of trying
to cope with a helium crunch. |
\"…\'tis man\'s perdition to be safe, when for the truth he ought to die.\"
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MagicJigPipe
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We could just set off a bunch of hydrogen bombs. That would be the most asthetically pleasing way Surely I'm not the only one that thinks a nuclear bomb going off is nothing short of majestic? It just looks so....
awe inspiring... Albeit destructive and environmentally detrimental. But it's just amazing. Especially fission induced fusion bombs.
[Edited on 2-1-2008 by MagicJigPipe]
[Edited on 2-1-2008 by MagicJigPipe]
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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chemkid
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beautiful
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Maya
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MJP,
I knew you were twisted....
look , the easiest way to extract He is from NG. extracting from air will be somewhat more cumbersome
\"Prefiero ser yo extranjero en otras patrias, a serlo en la mia\"
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Nixie
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This poster is on my room's wall (it was the only fusion bomb poster the poster place had):
<img src="http://imagecache2.allposters.com/images/pic/CFJ/2412~Hydrogen-Bomb-Posters.jpg">
[Edited on 2-1-2008 by Nixie]
\"Good is a product of the ethical and spiritual artistry of individuals; it cannot be mass-produced.\" --Aldous Huxley
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JohnWW
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| Quote: | | Originally posted by iamthewafflerAs far as synthetic helium, helium-3 is used quite commonly in ultra-low-temp research- the problem is that
it is of such low natural abundance (parts per million) for an already rare gas that it is not possible to separate a reasonable amount from the
naturally occurring. So it is in fact made artificially, by neutron bombardment of Li, N, and B, if memory serves. Despite the relatively large demand
(basically every university in the US, certainly, as well as many companies and government projects) the price is somewhere around US$5,000,000 per
kilogram . In other words, synthetic production involving nuclear transmutation
is mindblowingly expensive, even for a product with a large demand. |
That is why one of the purposes of NASA wanting to return to the Moon is to mine its surface rocks and soil for the large amounts of He-3 that have
been adsorbed fom the solar wind. It is likely to be cheaper than synthesizing He3 on Earth, or separating it from He in the atmosphere.
He-4 is formed largely in Earth's crust as alpha particles from the decay of U-238 and its daughter decay products. A small amount is from even
longer-lived rare earth and actinide element isotopes such as Th-232. U and Th and rare-earth elements all occur in granite, especially in the lower
depths (pegmatite) of granite masses, and in sedimentary and metamorphic rocks derived from granite. It is in such sedimentary rocks that the natural
gas deposits, containing He, of Texas and Poland occur.
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MagicJigPipe
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| Quote: | Originally posted by The_Davster
The He intended for use in balloon filling is diluted with oxygen so that people who inhale He to make their voice funny do not suffocate themselves.
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This is wrong in at least one case and it's likely that most others do not have oxygen and/or nitrogen in them (that is usually reserved for deep
water SCUBA applications, eg heliox and heliair). The balloon kits that are sold at Wal-Mart are 99.99% helium (I just called the company and it also
says so on their MSDS). I'm sure this is because customers don't want to waste money, weight and cylinder space by filling 20% of it with oxygen.
Also, this would surely decrease bouyancy quite a bit.
Now that I know this I'm going to buy a couple for small inert gas uses in the lab. They even have a conveinient nossle and valve for semi-controlled
release rates. It's no regulator but it should suffice for many uses. I can't believe people waste He on balloons!
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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DrP
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So can't they use Nitrogen or some other gas - Or is it not cold enough to get the superconductivity they can get with liquid He temperatures?
[Edited on 13-5-2008 by DrP]
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
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Pulverulescent
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| Quote: | Originally posted by MagicJigPipe
Especially fission induced fusion bombs.
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'Didn't know there was any other kind?
P
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ScienceGeek
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| Quote: | Originally posted by DrP
So can't they use Nitrogen or some other gas - Or is it not cold enough to get the superconductivity they can get with liquid He temperatures?
[Edited on 13-5-2008 by DrP] |
I asked the HNMR operator at the local University that same question, and he said that it is simply more expensive to use materials that are
superconductive at higher temperatures, as opposed to use liquid Helium.
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-jeffB
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| Quote: | Originally posted by DrP
So can't they use Nitrogen or some other gas - Or is it not cold enough to get the superconductivity they can get with liquid He temperatures?
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No, it's not. Even for the experimentation our group does with "high-temperature" superconducting sensor coils for MRI, we chill them near
liquid-helium temperatures, because even high-Tc superconductors have better characteristics at lower temps.
There are research groups trying to develop MRI magnets that use high-Tc superconductors, but it's still a long way from commercialization.
There are other ways to reach the required low temperatures, but none are practical at present for a volume as large as an MRI magnet. Some clinical
systems do have closed-cycle helium cooling, but most as I understand it do not -- they just vent evaporated helium into the air.
If helium gets much more expensive, or if it starts to be rationed, clinics will move to install reclamation systems. At present, it's not seen as
offering a good return on investment. Collecting, compressing and reprocessing liquid helium is a pretty big undertaking.
(Apparently, at one point, our hospital actually ran a tube underground from their MRI facility to a room in the physics building. In that 20x20-foot
room, they put a huge bladder, which would collect helium until it filled most of the room. At that point, they'd recompress the helium for
reprocessing. Eventually, they stopped bothering.)
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MagicJigPipe
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| Quote: | Originally posted by Pulverulescent
| Quote: | Originally posted by MagicJigPipe
Especially fission induced fusion bombs.
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'Didn't know there was any other kind?
P |
Well, yeah but I didn't want to just say "fusion bomb" as it is possible to build a purely fusion bomb. Maybe a fusion bomb was created that we just
don't know about
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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12AX7
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| Quote: | Originally posted by ScienceGeek
| Quote: | Originally posted by DrP
So can't they use Nitrogen or some other gas - Or is it not cold enough to get the superconductivity they can get with liquid He temperatures?
|
I asked the HNMR operator at the local University that same question, and he said that it is simply more expensive to use materials that are
superconductive at higher temperatures, as opposed to use liquid Helium. |
Specifically, critical field varies with temperature, so even high-Tc superconductors needs to be cooled substantially before they can carry any
appreciable current (current flow means magnetic field generated at the surface of the superconductor). Relatively warm type I superconductors (which
are more robust in mechanical and conductive characteristics) are used for this reason.
Tim
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ShadowWarrior4444
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| Quote: | Originally posted by 12AX7
Specifically, critical field varies with temperature, so even high-Tc superconductors needs to be cooled substantially before they can carry any
appreciable current (current flow means magnetic field generated at the surface of the superconductor). Relatively warm type I superconductors (which
are more robust in mechanical and conductive characteristics) are used for this reason.
Tim |
A useful book on High Temperature Superconductivity for those interested: Introduction to High-temperature Superconductivity By Thomas P. Sheahen
I would also like to mention that superconducting power cables are being installed in my area as I write this. (New York City area) In the core is a
liquid nitrogen pipeline, surrounded by a high-temp superconductor, most likely YBCO. They may use mercury-based ones for the larger margin of error,
though--163 Kelvin, as opposed to 92 for YBCO.
Hospitals may not want to use high-tc superconductors due to the fact that most of them are ceramics, and therefore difficult to wind into coils.
(Accidentally breaking a ceramic coil would also mean replacing the entire device, unless one had a particularly clever in situ sol-gel repair system,
such as the ones used to make fiberoptic chemical sensors.)
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MagicJigPipe
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Seems like it would use more energy to produce the LNO2 than would be saved by using the superconductor.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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ShadowWarrior4444
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| Quote: | Originally posted by MagicJigPipe
Seems like it would use more energy to produce the LNO2 than would be saved by using the superconductor. |
For transferring power into NYC/LI from the upstate hydroelectrics? This is one of the highest population density areas in the US. The money saved
from zero resistive losses far outweighs LN2 production. Also, it is likely that they simply recycle the LN2 at either end, never allowing it to
become gaseous, thereby avoiding the need to fractionally distill from air.
It will probably be configured so that there are two or more wires transferring LN2 in opposite directions and being cooled at both ends, possibly by
Stirling coolers for the efficiency.
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MagicJigPipe
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I just never thought the loss was so much as to justify something like that. I suppose it must be a great distance. Damn, I just can't imagine the
energy it must take to keep that much mass at such a low temperature. Really though, if this is so cost effective, you would think every electrical
company with the same population/electricity demand density dynamics would employ this method. I mean, that's what the US is all about, saving money
to make money. I'm not saying I don't believe it, I'm simply saying I'm not so sure that it would save that much energy.
Imagine how massive the wires must be (total).
[Edited on 5-13-2008 by MagicJigPipe]
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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