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Superconductivity at room temperature?


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#1 AnBr

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Posted 13 September 2018 - 01:15 AM

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#2 LFC

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Posted 13 September 2018 - 09:13 AM

Sounds like two somebodies still got some serious splainin' to do.
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#3 D. C. Sessions

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Posted 14 September 2018 - 09:30 AM

Quote

If superconductivity could be harnessed at room temperature, it would allow for the free transport of energy, wildly faster computers, and incredibly precise sensors. Indeed, it would fundamentally change the world.

Mmmmm ... not quite. There are two obstacles to long-range power distribution with superconductors, and temperature is only one of them -- arguably the lesser.

The other is that superconduction is incompatible with magnetic fields. For weak fields, the superconductor excludes the field; that's how you get the liquid-nitrogen cooled [1] object floating above a magnet. Stronger fields, like in medical instruments, the LHC, and power systems kills the superconductivity. The consequences can be can be pretty spectacular. Every superconductor has what's called its "critical field" where the superconductor "goes normal." So if these folk have demonstrated superconductivity on the small scale at temperatures above 273 K, they still have to demonstrate it at high current densities.

[2] Superconductivity at LN2 temperatures is pretty recent itself.
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#4 baw1064

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Posted 14 September 2018 - 05:03 PM

View PostD. C. Sessions, on 14 September 2018 - 09:30 AM, said:

Mmmmm ... not quite. There are two obstacles to long-range power distribution with superconductors, and temperature is only one of them -- arguably the lesser.

The other is that superconduction is incompatible with magnetic fields. For weak fields, the superconductor excludes the field; that's how you get the liquid-nitrogen cooled [1] object floating above a magnet. Stronger fields, like in medical instruments, the LHC, and power systems kills the superconductivity. The consequences can be can be pretty spectacular. Every superconductor has what's called its "critical field" where the superconductor "goes normal." So if these folk have demonstrated superconductivity on the small scale at temperatures above 273 K, they still have to demonstrate it at high current densities.

The transition temperature which is normally reported is the one at zero magnetic field. The more one lowers the temperature from there, the higher magnetic field the material can support and remain superconductive. But a zero field transition temperature of 273K would mean you can support a very large magnetic field at 77K (liquid nitrogen temperature) and remain superconductive. So not all bad.
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