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The first room-temperature ambient-pressure superconductor?

arxiv.org

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Re: The first room-temperature ambient-pressure superconductor?

#381

Post by amatecha »

petsfed wrote: post #350
xxpor wrote: post #322

Earlier quoted context omitted.

One catch would be the use of lead would restrict the use cases fairly heavily

Its not a dirty secret, but just like the rules on chemicals under the organic certification, if you can show that there's no way to do what you want to do with lead-free, you can get an exemption. I suspect that "significantly lowers the cost of power generation" would outweigh "contains lead".

Yeah, I just mentioned in another comment that there already exist exemptions such as server/networking hardware:

"Lead in solders for servers, storage and storage array systems, network infrastructure equipment for switching, signalling, transmission, and network management for telecommunications"

( https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A... )

Re: The first room-temperature ambient-pressure superconductor?

#382

Post by barnabee »

eterevsky wrote: post #51
slashdev wrote: post #21

This is an unreviewed preprint coming out of South Korea. If it’s reproducible it would be the biggest scientific discovery of the last hundred years. It will literally reshape the world. However, the most likely thing is they made a mistake and the paper will be withdrawn. But imagine if it’s true.

> the biggest scientific discovery of the last hundred years I would say that electronic computers would take take the first spot for me, but I don't deny that room-temperature superconductors would be pretty close to the top.

Discovery vs invention

Re: The first room-temperature ambient-pressure superconductor?

#383

Post by solarmist »

piyh wrote: post #368
solarmist wrote: post #310

Earlier quoted context omitted.

In the video, it's when they stop moving the magnet, it maintains its position, neither repelling nor attracting. Several physicists have spoken up and said this, and a few other tells distinguishes it from any conventional materials, which is why they made the video to begin with I'm sure. That said I'm just parroting back the things I've picked up from this discussion.

Unmoving copper also neither repels or attracts a magnet. Eddy currents impede movement of non ferrous metals in a static magnetic field. This looks like slow motion falling or resistance to spinning when the metal is in a fixed field. This is how auto belays work. If you move the magnet, the metal will also move since you're inducing a current and the fields from the eddy currents will react against the moving magne…

> This is how auto belays work.

That is super cool!

That said, I'm enough of a layman not to be able to connect this explanation to what I saw in the video.

Are you saying because it wasn't moving in "slow motion," we can rule out non-ferrous metals? Or are you saying the alternating movement/stillness of the magnet shows this?

Re: The first room-temperature ambient-pressure superconductor?

#384

Post by amatecha »

JumpCrisscross wrote: post #379
amatecha wrote: post #366

Earlier quoted context omitted.

It's like fundamental best practice to always wash your hands thoroughly with soap if you handle leaded solder. You might want to read more in the links I shared about the harmful effects of lead before "whatabouting" to other problems of electronics recycling/waste. and yes, it's entirely possible this application would get an exemption from usual restrictions on lead. For example in the EU directive, one of the exe…

> fundamental best practice to always wash your hands thoroughly with soap if you handle leaded solder But people don't, particularly students, and sometimes they also let their irons run too hot at which point fumes become an issue. Also, there is an easy alternative, so why not. If the choice is lead superconductor or not, nobody is going to pause on a use case because there is lead. If they do, and if this is real…

Oh, sure. You could have just said that then. You instead originally said something about "no one licks the insides of the computers", which isn't the reason lead in electronics/PCBs/etc. is restricted, and what I was pointing out.

Re: The first room-temperature ambient-pressure superconductor?

#385

Post by fijiaarone »

xxpor wrote: post #322
sheepscreek wrote: post #48

One of the authors in a related paper[1] is Hyun-Tak Kim. He has many publications in peer-reviewed journals[2]. One even has > 1500 citations[3]. I can't tell if there is a catch anywhere, this seems pretty legitimate. Also, unlike some previous claims that required sophisticated setup to reproduce, this seems dead simple. I think we will hear from other researchers very soon. 1. Superconductor Pb10-xCux(PO4)6O show…

One catch would be the use of lead would restrict the use cases fairly heavily

If you think lead is scary, wait till you hear about carbon dioxide.

Re: The first room-temperature ambient-pressure superconductor?

#387

Post by JumpCrisscross »

amatecha wrote: post #384
JumpCrisscross wrote: post #379

Earlier quoted context omitted.

> fundamental best practice to always wash your hands thoroughly with soap if you handle leaded solder But people don't, particularly students, and sometimes they also let their irons run too hot at which point fumes become an issue. Also, there is an easy alternative, so why not. If the choice is lead superconductor or not, nobody is going to pause on a use case because there is lead. If they do, and if this is real…

Oh, sure. You could have just said that then. You instead originally said something about "no one licks the insides of the computers", which isn't the reason lead in electronics/PCBs/etc. is restricted, and what I was pointing out.

Was being cheeky in response to OP claiming "the use of lead would restrict the use cases fairly heavily."

Re: The first room-temperature ambient-pressure superconductor?

#388

Post by lilgreenland »

solarmist wrote: post #310
lilgreenland wrote: post #272

Earlier quoted context omitted.

Copper does this already. It's not like ferromagnets. https://www.youtube.com/watch?v=sENgdSF8ppA

In the video, it's when they stop moving the magnet, it maintains its position, neither repelling nor attracting. Several physicists have spoken up and said this, and a few other tells distinguishes it from any conventional materials, which is why they made the video to begin with I'm sure. That said I'm just parroting back the things I've picked up from this discussion.

When does the hanging copper maintain a position in the video? https://www.youtube.com/watch?v=EtVjGWpbE7k

All I see is the normal dampening and dragging effects that I show in my physics classroom.

Re: The first room-temperature ambient-pressure superconductor?

#389

Post by andreiklochko »

Guys, even if everything in this paper is true, the material as it is might have limited applications.

From what they show, the critical field and critical current seem very low. 2500 Oe is like 0.25 Tesla. Even REBCO at 77K is >1T. And 2500 Oe is not even at critical temperature but much lower. From skimming through the article I couldn't find the sample size of the current measurement to get the critical current density, not just current which is meaningless (and around 300 mA).

This means you can't actually push big current through this thing (yet). You can't make a powerful magnet, and you can't make viable power lines, both applications that were the hallmark of "room temperature superconductor revolution".

Of course, maybe one or a few more tweak(s) of the material and boom, it will give high J_c and B_c. I really hope it does, it would be super cool!

Re: The first room-temperature ambient-pressure superconductor?

#390

Post by benlivengood »

thfuran wrote: post #343
benlivengood wrote: post #58

Earlier quoted context omitted.

Specifically you could lay undersea superconducting cables around the world and rely on a global electrical grid which allows for nearly 100% solar generation. Superconducting magnets become cheap and widely available which allows for maglev trains at massive scale. Costs for the LHC and similar experiments would drop dramatically. MRIs would only require air conditioning, if that; Modern cell phones are sufficient t…

Global electric grids aren't on a common standard. They're not all the same frequency or voltage, so you can't just wire them together. And changing over would be a mess. MRIs require very high field strength that this superconductor likely cannot sustain.

But the interties between grids are often high voltage DC which would work fine between incompatible AC grids. I think, but am not sure, that you'd always want DC superconducting transmission lines to avoid inductive losses.
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