"Kurt Ullman"  wrote in message
news:kurtullman-7E7A14.18482010052007{at}customer-201-125-217-207.uninet.net.mx...
> In article ,
>  "Carl"  wrote:
>
> > Josh Hill wrote:
> > > On Thu, 10 May 2007 11:23:11 GMT, Kurt Ullman

> > > wrote:
> > 
> >
> > >>      I knew we were lost even with RR and NG when we couldn't even
> > >> get the Helium reserve unfunded.
> > >
> > > I seem to remember once having read that we're running out of helium.
> >
> > The last I heard, the US had something like 300 x the rest of the world
> > combined.
> >
> > What did we use it on?
>  Bunches of things:
>  Balloons and other lighter-than-air craft, a mixture of helium and
> oxygen is often used as a breathing mixture for deep-sea divers and
> caisson workers and is used in decompression chambers; because helium is
> less soluble in human blood than nitrogen, its use reduces the risk of
> caisson disease, or the ³bends.² Helium can also be used wherever an

Helium also does not have the narcotic effect of nitrogen, so you can go
deeper, particlarly if you reduce O2 content as well
(at the higher partial pressures at depth you can still breathe it happily,
even though the mix may be hypoxic at the surface. That's done to avoid
oxygen toxicity.

> unreactive atmosphere is needed, e.g., in electric arc welding, in
> growing crystals of silicon and germanium for semiconductors, and in
> refining titanium and zirconium metals. It is also used to pressurize
> the fuel tanks of liquid-fueled rockets. Liquid helium is essential for
> many low temperature applications.
>      Now you know.
>

Dennis


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