5 ms·

Superconductor though. A semiconductor is a material that is somewhere in between conductor and insulator and varies depending on things like temperature or cu

Superconductor though. A semiconductor is a material that is somewhere in between conductor and insulator and varies depending on things like temperature or current direction. That is the material used in transistors and diodes. I would say we are very far away even if this proves to be it. First you would need to manufacture it reliably, then reliably without impurities, then reliably in some constrained 2d/3d geometry. Then you can start thinking about small footprint applications like IC design (chips and sensors). Perhaps then scale it to PCB design and RF applications like coplanar waveguides. With that alone you would enter a new era in electronics with virtually no 'thermal noise' and no residual heat. Beyond that (think large coils, motors, electromagnets) you would need a very large design step. As far as I understand this is still a very brittle ceramic, manufacturing very large or very long chains of this material would be unlikely. So the floating trains are probably a bit further away into the future.

NoMoreNicksLeft 3y ago
Supposing this lead apatite if conducive, can we not use it for high voltage cables? Some absurd level of energy loss occurs in those. I understand that there are current limitations inherent in superconductors, but is there no way to scale this?
- klodolph 3y ago
  The cost of losses in the cables may be high, but the cost of superconducting cables may be much higher. Superconductors may be fragile and unsuitable for cables.
- arcticbull 3y ago
  > Some absurd level of energy loss occurs in those. It doesn't really - because we do the transmission at very high voltage, and the power loss is proportional to 1/V. Power loss in transmission in the US is about 5%. In the transmission lines themselves it's only 2-4%. [1] If you ran a power line all the way across the entire continental United States, you'd still get about 80% of the power out of the other end. The longest economically effective distance you can run an AC power line is about 2500mi, and DC around 4300mi. [2] [1] https://chintglobal.com/blog/how-much-power-loss-in-transmission-lines/ https://chintglobal.com/blog/how-much-power-loss-in-transmis... [2] https://en.wikipedia.org/wiki/Electric_power_transmission#cite_note-limits-of-very-long-distance-22 https://en.wikipedia.org/wiki/Electric_power_transmission#ci...
  - throwaway60707 3y ago
    "Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km (620 mi), about 50% less than AC (6.7%) lines at the same voltage." https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current This seems pretty significant. We don't have much losses because we don't transmit energy over long distances. But now we could.
    - arcticbull 3y ago
      We definitely do, we just don't want to pay to string up wire thousands of miles, let alone superconducting wire. The difference between keeping 98% of the power that goes through a wire, or 100%, isn't the reason we don't do it. To quantify it further, the current US grid loses 5% to transmission losses which is just less than a cent per kWh. Most power is generated in a centralized way anyways because it's much more efficient that way. The 'dregs' aren't connected because putting up the wire costs far more than the extra power yields. A few percentage points more efficient won't change the economics, especially if the wire is (a) lead and (b) dramatically more expensive. 3.5% per 1000km is respectfully, basically nothing. You'd get 85% of the power out of a line from SF to NY. I'm not saying there aren't use cases for room temperature superconductors, I'm saying this is not one that's going to be top of the list.
      - throwaway60707 3y ago
        > 3.5% per 1000km is respectfully, basically nothing. You'd get 85% of the power out of a line from SF to NY. But why connect SF to NY - what's the advantage? What about connecting a place where it's midnight with a place where it's noon? That'd allow you to use solar arrays instead of local coal/gas/nuclear power plants.
        deleted 3y ago
        [deleted]
        linuxdude314 3y ago
- ufo 3y ago
  One challenge is that these superconductors are ceramic. Brittle and inflexible.
  - jacquesm 3y ago
    Ceramics materials science has come a long way since the days of clay pots and flexible ceramics are definitely a possibility, depending on how thick you want them to be. Whether that is compatible with superconductivity is of course an open question but I wouldn't rule out a compound that is and superconducting and has a usable bending radius in at least one dimension.
    - andrewflnr 3y ago
      The theory of this particular alleged superconductor is that it's a result of internal stress. I don't think that's compatible with bending.
      - jacquesm 3y ago
        Internal stress in one direction.
        andrewflnr 3y ago
        The material on the outside and inside of the bend radius is being stretched and compressed, respectively, along the direction of conduction (assuming any of the anisotropy stuff is more than speculation).
        jacquesm 3y ago
        Yes, typically that results in a specific minimum bending radius to ensure material properties are not adversely affected.
- linuxdude314 3y ago
  This is already done, just not at great scale. https://en.wikipedia.org/wiki/Superconducting_wire https://en.wikipedia.org/wiki/Superconducting_wire For detailed information about one actually built and used: https://www.furukawa.co.jp/review/fr035/fr35_04.pdf https://www.furukawa.co.jp/review/fr035/fr35_04.pdf The enthusasiam is nice but there's a lot of NIH going on. I'd encourage people to research subject matter before thinking no one else has had similar ideas before. It's "easy to make" in a sense, but the yields are insanely low (think 1/1000) or less of input materials. This indicates there are some variables that either are not controlled for or cannot be controlled. That being said, its still early but it looks like LK-99 is not what we typically think about when we think of a super conductor. If we can figure out a good way to make it (with time we likely will), it will still have applications, just likely not high power transmission ones.
spaceman_2020 3y ago
I think the financial incentives will speed things up a great deal. Any business that can reliably manufacture it at scale stands to make billions. That usually spurs a lot of innovation.
iraqmtpizza 3y ago
so a 100 GHz CPU could be not so far away
- thechao 3y ago
  A 100Ghz CPU would be limited by other factors; mostly c.
  - jacquesm 3y ago
    That's true, but superconduction would change things from being planar to being cubic and that alone would give a huge boost to speed. Because one main limitation is to be able to get rid of the heat and building 'up' makes that very hard right now.
- js8 3y ago
  AFAIK CPU speeds are mainly limited by speed of light already today. There is tradeoff between time to fetch data from L1 cache (or register file), and their size. If you want to fetch the data faster, the cache has to be smaller (or the pipeline will stall), because the signal won't propagate fast enough to the cache. But smaller L1 cache also has negative performance impact, because more data has to be refetched from deeper caches.

NoMoreNicksLeft 3y ago

Supposing this lead apatite if conducive, can we not use it for high voltage cables? Some absurd level of energy loss occurs in those. I understand that there are current limitations inherent in superconductors, but is there no way to scale this?

klodolph 3y ago
The cost of losses in the cables may be high, but the cost of superconducting cables may be much higher. Superconductors may be fragile and unsuitable for cables.
arcticbull 3y ago
> Some absurd level of energy loss occurs in those. It doesn't really - because we do the transmission at very high voltage, and the power loss is proportional to 1/V. Power loss in transmission in the US is about 5%. In the transmission lines themselves it's only 2-4%. [1] If you ran a power line all the way across the entire continental United States, you'd still get about 80% of the power out of the other end. The longest economically effective distance you can run an AC power line is about 2500mi, and DC around 4300mi. [2] [1] https://chintglobal.com/blog/how-much-power-loss-in-transmission-lines/ https://chintglobal.com/blog/how-much-power-loss-in-transmis... [2] https://en.wikipedia.org/wiki/Electric_power_transmission#cite_note-limits-of-very-long-distance-22 https://en.wikipedia.org/wiki/Electric_power_transmission#ci...
- throwaway60707 3y ago
  "Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km (620 mi), about 50% less than AC (6.7%) lines at the same voltage." https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current This seems pretty significant. We don't have much losses because we don't transmit energy over long distances. But now we could.
  - arcticbull 3y ago
    We definitely do, we just don't want to pay to string up wire thousands of miles, let alone superconducting wire. The difference between keeping 98% of the power that goes through a wire, or 100%, isn't the reason we don't do it. To quantify it further, the current US grid loses 5% to transmission losses which is just less than a cent per kWh. Most power is generated in a centralized way anyways because it's much more efficient that way. The 'dregs' aren't connected because putting up the wire costs far more than the extra power yields. A few percentage points more efficient won't change the economics, especially if the wire is (a) lead and (b) dramatically more expensive. 3.5% per 1000km is respectfully, basically nothing. You'd get 85% of the power out of a line from SF to NY. I'm not saying there aren't use cases for room temperature superconductors, I'm saying this is not one that's going to be top of the list.
    - throwaway60707 3y ago
      > 3.5% per 1000km is respectfully, basically nothing. You'd get 85% of the power out of a line from SF to NY. But why connect SF to NY - what's the advantage? What about connecting a place where it's midnight with a place where it's noon? That'd allow you to use solar arrays instead of local coal/gas/nuclear power plants.
      - deleted 3y ago
        [deleted]
      - linuxdude314 3y ago
ufo 3y ago
One challenge is that these superconductors are ceramic. Brittle and inflexible.
- jacquesm 3y ago
  Ceramics materials science has come a long way since the days of clay pots and flexible ceramics are definitely a possibility, depending on how thick you want them to be. Whether that is compatible with superconductivity is of course an open question but I wouldn't rule out a compound that is and superconducting and has a usable bending radius in at least one dimension.
  - andrewflnr 3y ago
    The theory of this particular alleged superconductor is that it's a result of internal stress. I don't think that's compatible with bending.
    - jacquesm 3y ago
      Internal stress in one direction.
      - andrewflnr 3y ago
        The material on the outside and inside of the bend radius is being stretched and compressed, respectively, along the direction of conduction (assuming any of the anisotropy stuff is more than speculation).
        jacquesm 3y ago
        Yes, typically that results in a specific minimum bending radius to ensure material properties are not adversely affected.
linuxdude314 3y ago
This is already done, just not at great scale. https://en.wikipedia.org/wiki/Superconducting_wire https://en.wikipedia.org/wiki/Superconducting_wire For detailed information about one actually built and used: https://www.furukawa.co.jp/review/fr035/fr35_04.pdf https://www.furukawa.co.jp/review/fr035/fr35_04.pdf The enthusasiam is nice but there's a lot of NIH going on. I'd encourage people to research subject matter before thinking no one else has had similar ideas before. It's "easy to make" in a sense, but the yields are insanely low (think 1/1000) or less of input materials. This indicates there are some variables that either are not controlled for or cannot be controlled. That being said, its still early but it looks like LK-99 is not what we typically think about when we think of a super conductor. If we can figure out a good way to make it (with time we likely will), it will still have applications, just likely not high power transmission ones.

spaceman_2020 3y ago

I think the financial incentives will speed things up a great deal. Any business that can reliably manufacture it at scale stands to make billions. That usually spurs a lot of innovation.

iraqmtpizza 3y ago

so a 100 GHz CPU could be not so far away

thechao 3y ago
A 100Ghz CPU would be limited by other factors; mostly c.
- jacquesm 3y ago
  That's true, but superconduction would change things from being planar to being cubic and that alone would give a huge boost to speed. Because one main limitation is to be able to get rid of the heat and building 'up' makes that very hard right now.
js8 3y ago
AFAIK CPU speeds are mainly limited by speed of light already today. There is tradeoff between time to fetch data from L1 cache (or register file), and their size. If you want to fetch the data faster, the cache has to be smaller (or the pipeline will stall), because the signal won't propagate fast enough to the cache. But smaller L1 cache also has negative performance impact, because more data has to be refetched from deeper caches.