The Maglev Mirage | 78 comments (73 topical, 5 editorial, 0 hidden)

Re: The Maglev Mirage (none / 0)

High-temperature superconductors are generally considered to be those that demonstrate superconductivity at or above the temperature of liquid nitrogen, or −196 °C (77 K), since this is the most easily attainable cryogenic temperature.

If you need to cool the track with liquid nitrogen, I'm afraid it's not a practical technology. this side of the asteroid belt.

Those whom the Gods wish to destroy They first make mad. -- Euripides

by Carrie (migeru at eurotrib dot com) on Tue Sep 26th, 2006 at 12:17:22 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 0)

The killer app is, of course, the Uranus Ring Express.

by Colman (colman at eurotrib.com) on Tue Sep 26th, 2006 at 12:26:33 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 1)

Especially after a good Vindaloo...

You can't be me, I'm taken

by Sven Triloqvist on Tue Sep 26th, 2006 at 12:56:43 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 0)

Well, wouldnt only the magnets have to be cooled? And they have gotten superconductors up to 177K according to that link. Not saying it would be very practical, just questioning whether it is completely off the table. (Not that I consider the asteorid belt to be the limit for that, as we are fast approaching a level of robotics where asteorids could be remotely mined. But that is a digression I guess.)

by Trond Ove on Tue Sep 26th, 2006 at 12:31:02 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 0)

I mention the asteroid belt not because I want to mine it, but because outside it there are actually worlds with atmospheres and oceans where these temperatures are ambient temperatures.

Those whom the Gods wish to destroy They first make mad. -- Euripides

by Carrie (migeru at eurotrib dot com) on Tue Sep 26th, 2006 at 12:33:55 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 0)

Ah, different perspectives...

by Trond Ove on Tue Sep 26th, 2006 at 01:04:31 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 1)

If all you want is a low equilibrium temperature, in free space it suffices to have a good-quality sunshade. In the shadow, objects get negligible heating and radiate into the heat sink of interstellar space. (The heat capacity of vacuum is pretty good, per cubic lightyear.)

Of course, the T^4 dependence of black body radiation makes the radiated power damn small at low temperatures. It's about 460 W/m^2 around room temperature (300 K), but only 2 W/m^2 at the boiling point of nitrogen (77 K).

Words and ideas I offer here may be used freely and without attribution.

by technopolitical on Tue Sep 26th, 2006 at 02:35:24 PM EST
[ Parent ]

Re: The Maglev Mirage (none / 0)

Hooooweeee!

I approach the arcane as Schumaker approaches a chicane - seeking a safe line through, but at the same time aware of the possibilities for mischief against my competitors.

You can't be me, I'm taken

by Sven Triloqvist on Thu Sep 28th, 2006 at 06:25:54 PM EST
[ Parent ]

Re: The Maglev Mirage (4.00 / 2)

IIRC, the superconductivity of these materials breaks down when the magnetic field reaches a certain intensity. Also, the materials themselves are exceedingly brittle, and technologies for using them in real-world applications are still in the laboratory stage.

The fact is that what we're experiencing right now is a top-down disaster. -Paul Krugman

by dvx (dvx.clt ät gmail dotcom) on Wed Sep 27th, 2006 at 04:18:01 AM EST
[ Parent ]

Re: The Maglev Mirage (none / 1)

The high-Tc materials can tolerate quite high magnetic fields, but problems including brittleness have indeed kept them from creeping out of the laboratory more than a very little.

Words and ideas I offer here may be used freely and without attribution.

by technopolitical on Wed Sep 27th, 2006 at 06:50:09 PM EST
[ Parent ]

The Maglev Mirage | 78 comments (73 topical, 5 editorial, 0 hidden)

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