3 ms·

Is the diamagnetism itself useful? In other words, even if it's not superconducting, does this have industrial applications?

adrian_b 3y ago
One possible application for a cheap strongly diamagnetic material would be in passive diamagnetic bearings for replacing the active magnetic bearings that are used in flywheels with very high rotational speeds. This would cause a reduction in cost and size and an increase in energy efficiency, which could make the flywheels competitive for more energy storage applications than the niches where they are used now (i.e. for very high power density, but low energy density and short storage times).
- jacquesm 3y ago
  This is already possible using Halbach arrays with compensating coils. It only needs a bit of support until it 'takes off', after that it is entirely self correcting.
  - richk449 3y ago
    Do you have a link to this? I’m interested to learn more.
    - jacquesm 3y ago
      Huge list of papers: https://www.science.gov/topicpages/h/halbach+magnetic+bearing https://www.science.gov/topicpages/h/halbach+magnetic+bearin... Here is one for planar arrays: https://www.researchgate.net/publication/228401193_Electrodynamic_passive_magnetic_bearing_with_planar_halbach_arrays https://www.researchgate.net/publication/228401193_Electrody... Here is one that apparently doesn't need the coils either (haven't checked it beyond the abstract): https://www.sciencedirect.com/science/article/abs/pii/S0304885311001181 https://www.sciencedirect.com/science/article/abs/pii/S03048...
    - throwawaymaths 3y ago
      I think he's referring to inductrack: https://en.m.wikipedia.org/wiki/Inductrack https://en.m.wikipedia.org/wiki/Inductrack Never really took off due to IP, which I believe recently expired
      - jacquesm 3y ago
        No, I'm referring to a circular arrangement, not a planar one, but the effects are much the same, think of it as a rolled up version of a Halbach array with coils connected across the opposing sides in such a way that bringing the coil closer to the side will increase the attractive force on the other side. It's a pretty clever arrangement, that requires no control electronics and has very low loss once it has centered itself.
codexb 3y ago
Free mag-lev? Yeah, that's useful.

adrian_b 3y ago

One possible application for a cheap strongly diamagnetic material would be in passive diamagnetic bearings for replacing the active magnetic bearings that are used in flywheels with very high rotational speeds. This would cause a reduction in cost and size and an increase in energy efficiency, which could make the flywheels competitive for more energy storage applications than the niches where they are used now (i.e. for very high power density, but low energy density and short storage times).

jacquesm 3y ago
This is already possible using Halbach arrays with compensating coils. It only needs a bit of support until it 'takes off', after that it is entirely self correcting.
- richk449 3y ago
  Do you have a link to this? I’m interested to learn more.
  - jacquesm 3y ago
    Huge list of papers: https://www.science.gov/topicpages/h/halbach+magnetic+bearing https://www.science.gov/topicpages/h/halbach+magnetic+bearin... Here is one for planar arrays: https://www.researchgate.net/publication/228401193_Electrodynamic_passive_magnetic_bearing_with_planar_halbach_arrays https://www.researchgate.net/publication/228401193_Electrody... Here is one that apparently doesn't need the coils either (haven't checked it beyond the abstract): https://www.sciencedirect.com/science/article/abs/pii/S0304885311001181 https://www.sciencedirect.com/science/article/abs/pii/S03048...
  - throwawaymaths 3y ago
    I think he's referring to inductrack: https://en.m.wikipedia.org/wiki/Inductrack https://en.m.wikipedia.org/wiki/Inductrack Never really took off due to IP, which I believe recently expired
    - jacquesm 3y ago
      No, I'm referring to a circular arrangement, not a planar one, but the effects are much the same, think of it as a rolled up version of a Halbach array with coils connected across the opposing sides in such a way that bringing the coil closer to the side will increase the attractive force on the other side. It's a pretty clever arrangement, that requires no control electronics and has very low loss once it has centered itself.

codexb 3y ago

Free mag-lev? Yeah, that's useful.