4 ms·

well you're not wrong but a room tc superconductor would indeed enable us to cut down on transmission costs of power. I'm not sure if this is obvious but the on

well you're not wrong but a room tc superconductor would indeed enable us to cut down on transmission costs of power. I'm not sure if this is obvious but the only reason national powergrids are AC and not DC is because you can step down AC current and therefore have much lower heat dissipation through the transmission lines. So at the minimum you'd get cheaper power by eliminating all the resistive losses and stepper circuits . But also superconductors are used in MRI machines where right now they're kept below Tc using liquid nitrogen, which is hard to control (search MRI quenching). So room temp superconductors would make MRIs cheaper, which would be a boon to the developing world.

amper5and 8y ago
Most MR units these days use liquid helium not liquid nitrogen. And there is at least one cryogen free unit on the market right now, though it’s definitely not the kind (open, 0.5T) you’d use to replace most hospital magnets.
wl 8y ago
A superconductor suitable for use in an electromagnet that could be cooled with liquid nitrogen alone would be practically "room temperature" as far as these things go. Liquid nitrogen is cheap and abundant, as opposed to liquid helium which is required to get down to 4 K. As stands at the moment, some older MRIs use liquid nitrogen to help insulate liquid helium. Newer machines use liquid helium alone.
- mrfusion 8y ago
  Doesn’t rebco tape use liquid nitrogen?
  - wl 8y ago
    It's been awhile since I've paid attention to the field, so apologies if I get this wrong. I was under the impression that cuprate superconductors were unsuitable for use in MRI magnets because they only superconduct across clusters of microdomains, making it impossible (at least with current technology) to generate the large, strong, and uniform field necessary for the application. There seems to be ongoing research into producing suitable magnets with cuprates, but I don't know if the problem has been solved yet. In any case, there are no commercially available MRI machines that use cuprate superconductors.

amper5and 8y ago

Most MR units these days use liquid helium not liquid nitrogen. And there is at least one cryogen free unit on the market right now, though it’s definitely not the kind (open, 0.5T) you’d use to replace most hospital magnets.

wl 8y ago

A superconductor suitable for use in an electromagnet that could be cooled with liquid nitrogen alone would be practically "room temperature" as far as these things go. Liquid nitrogen is cheap and abundant, as opposed to liquid helium which is required to get down to 4 K. As stands at the moment, some older MRIs use liquid nitrogen to help insulate liquid helium. Newer machines use liquid helium alone.

mrfusion 8y ago
Doesn’t rebco tape use liquid nitrogen?
- wl 8y ago
  It's been awhile since I've paid attention to the field, so apologies if I get this wrong. I was under the impression that cuprate superconductors were unsuitable for use in MRI magnets because they only superconduct across clusters of microdomains, making it impossible (at least with current technology) to generate the large, strong, and uniform field necessary for the application. There seems to be ongoing research into producing suitable magnets with cuprates, but I don't know if the problem has been solved yet. In any case, there are no commercially available MRI machines that use cuprate superconductors.