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Superconductor news: What’s claimed, and how strong the evidence seems to be

science.org

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Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#341

Post by superkuh »

carabiner wrote: post #226
superkuh wrote: post #43

Earlier quoted context omitted.

Search "superdirective superconducting antenna". With normal conductors the directivity of an antenna depends on how many wavelengths it spans; the summation of the currents over the effective aperture. With superconducting materials you can exploit the weirdness in current distribution to make very directional antennas that are small relative to the wavelength. It could be a game changer for making efficient directi…

Could we get high speed satellite internet on a cellphone?

Probably not. It will make the really small really inefficient antennas stuck in things like 2-5x better. But they still won't be outperforming full size resonant non-superconducting antenna.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#343

Post by fh973 »

distortionfield wrote: post #198
scarmig wrote: post #100

Earlier quoted context omitted.

Nice find.

Not really, it’s just more speculation about the experiment. It’s worth as much as anyone else’s salt about the matter.

It's from a guy of the Max Planck Institute for Solid State Research.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#345

Post by cornel_io »

beepbopboopp wrote: post #187
reaperman wrote: post #111

Earlier quoted context omitted.

> If it super conducts, but it isn't useful in the real world, then we will be waiting for theory to - hopefully - give us some insight into how to improve things to useful. This only can carry a small amount of current. Thank you for this. > This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Have you been to a hardware…

[flagged]

We 100% know why airplanes of every shape and size stay aloft, and can calculate lift/drag extremely accurately based on the geometry of the plane and the airflow, in both steady state and much worse conditions. We have great approximations for steady state that make perfect sense and simplify the situation greatly and make it more understandable without simulation, even if they gloss over some details.

Where are you getting this terrible information that we don't know how flight works? Have you ever talked to literally anyone who has worked in aeronautical engineering, or even studied the basics of fluid dynamics?

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#346

Post by denimnerd42 »

hinkley wrote: post #334
denimnerd42 wrote: post #331

Earlier quoted context omitted.

you sound highly confused, what is compressing? the rim? the spoke?

You need to reread Brandt. There are two situations when you can push on a string. One is when it’s frozen, and the other when it’s tensioned. How do you unload a bow string? You push it off the notches.

bro. you're wrong. just build a bicycle wheel some time. it becomes very obvious how they work as you take it through the various stages of tensioning.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#347

Post by denimnerd42 »

hinkley wrote: post #332
denimnerd42 wrote: post #330

Earlier quoted context omitted.

i own the book.. and also The Art of Wheelbuilding - Gerd Schraner of course in a properly built wheel usually all the spoke are under tension... i was just demonstrating the fact that the spokes on the upper half of the wheel are supporting the hub and are under greater tension than the bottom ones, the spokes on the bottom half of the wheel should remain in tension, but only through the fact that they are already u…

I think one of us needs to reread that book, because he emphatically denies that tension at the top of the wheel increases. It’s tension at the bottom that decreases. > of course in a properly built wheel usually all the spoke are under tension... No, a properly built wheel all of the spokes are always under enough tension you can bounce a penny off them. Always.

no. you're assuming the rim has no deflection which is untrue. if you build a rim out of schedule 80 steel pipe then yea. but 300-400-500g rims on high performance bikes do not act like that. the spokes are constantly loading and unloading tension as they bash through rocks and over jumps. the point is that the pretension on the wheel needs to be high enough the spokes do not loosen too much under these forces. if they do in fact loosen too much the nipples will begin to loosen and unwind and the wheel will become out of balance.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#350

Post by OfferFun6595 »

phyzome wrote: post #278
bluGill wrote: post #101

Earlier quoted context omitted.

That depends. If it super conducts, but it isn't useful in the real world, then we will be waiting for theory to - hopefully - give us some insight into how to improve things to useful. This only can carry a small amount of current. I'm not sure how to figure out what small means (numbers are given in the article if you know how to use them!), but if the losses using regular wire are less than the energy needed to ma…

Unfortunately, most companies seem to have little compunction about exposing workers, consumers, or the environment to toxic materials. The use of lead is not in any way a blocker, for better or worse.

It seems a 50/50 situation so long as the lead is able to get the products most companies don't seem to bother a lot about the risks of this exposure
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