It is much easier to prove that this is superconducting than to prove why.Īs another commenter has pointed out, the proposal of a new mechanism seems to be extraordinary and novel, and could lead to an explosion of new research, so it does indeed seem to be "relevant" on its merits. >I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. I think I only built a couple professionally, and usually singles. When a good customer comes in on Wednesday before an out of town bike ride you can’t afford to fuck it up. Only added an extra ten or fifteen minutes but it works a charm. I saved three or four wheels that would have been scrap by unwinding the spokes halfway and building it back up again like a wheel build. I was never the fastest, but if we had a customer we could not afford to disappoint, I or the senior mechanic got the job because my repairs did not come back. I then worked as a mechanic for two summers of college. My set, my spare that my brother road (into the ground - my first set and practically the only problematic ones, but he road over bumps without getting out of the saddle), a set my dad commissioned from me, and a pair that he had me build for a friend. I’ve built more than half a dozen bicycle wheels. Why do you think someone would talk about Brandt’s work if they hadn’t used it? I used his book to build half a dozen wheels or so and the information it contained to fix many more. IIRC, none of the prior models or theories for how a spoked wheel works could adequately explain how potato chipping happens. Cancel out all of the tension, and the wheel turns into a potato chip if you don’t reload it exactly, perfectly on axis. When you put the wheel on a surface and push down, the compression cancels out some of the tension on the bottom of the wheel. The tension instead first cancels out some of the compressive force on the two pieces of metal, before the bolt ever feels more load.Ĭonversely, all the spokes on the wheel are under tension. A tightened bolt compresses the two pieces of metal together, and when you tug on them, the bolt doesn’t stretch more. Bolts, I just learned a couple weeks ago, work in the opposite way. Jobst was a bike fanatic and a mechanical engineer.īike spokes are not loose, they’re under substantial tension. Jobst Brandt earned an obituary in Bicycling magazine including quotes from his friend Tom Ritchey (one of the original mountain bike makers). That book I linked has another name, “the wheel building bible”. I never rode when I lived in Seattle (Seattle drivers are nuts) but I don't live there anymore and I need to catch up on 20 years of tech. I really should figure out space to have a bike again. When I'm thinking of large computer systems I'm essentially thinking of them as physics problems. I was past my midlife crisis before I realized that I don't have a large working memory (smaller than average in fact) it's just that I've been doing mind palaces without pictures since I was very small. I don't know if I found Lego or Lego found me, but I definitely think in terms of shapes. Learned all sorts of things about metal fatigue and oddly enough picosecond lasers from him. One of my better friends in college was an ME. Software was just new and shiny enough and it let me build things with my mind, at a time when I believed I was clumsy (I actually have always had excellent fine motor skills, it's macro motor control I lagged behind in). I think I would have been a mechanical engineer if I were born 20 years earlier or 20 years later. If these data reproduce, the superconductivity of this material seems beyond doubt. And they demonstrate the behaviors that a superconductor should have, such as the Meissner effect (expulsion of a magnetic field), sudden resistivity changes at a critical temperature (bizarrely high though that is in this case), current-voltage (I-V) plots at different temperatures and under different magnetic field strengths, etc. I am not enough of a solid-state physicist to judge this proposal, but the authors are making a detailed mechanistic claim that is subject to experimental proof, which is very good to see, and and they adduce a good deal of data to back it up (x-ray diffraction, EPR, and more). They propose that electron tunneling between these quantum wells, which are between 3.7 and 6.5 Ångstroms apart, is the superconducting mechanism. > The authors believe that the modified/strained structure of their material creates a large number of “quantum wells” between particular lead atoms and the adjacent oxygens of the phosphate groups bound to them, in effect making a two-dimensional “electron gas”. This is an extremely useful summarization of the original paper.
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