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Andrew McCalip demonstrates synthesis of LK99

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Re: Andrew McCalip demonstrates synthesis of LK99

#341

Post by brakedam »

cthalupa wrote: post #338
brakedam wrote: post #334

Earlier quoted context omitted.

Now I understand what's going on in South Korea. Okay, this is more political than I thought. But the problem is, the researchers even didn't send the sample abroad to prove it. Even though they had many requests for a week. This doesn't make sense, and that kind of background story is not helpful in solving this.

It would not be a normal part of the process for people to be demanding samples just because there was a preprint posted on arxiv. It's a weird situation and they don't owe anyone any of these samples. They say they want to share samples after they get a peer reviewed paper published. That's not a weird position to be in. If it wasn't for the hype around this, they wouldn't be in this position. Let the process play o…

This case is something different. Because everyone reviewed their Arxiv papers and found that there’s no meaningful figure for the resistivity. And even magnetization data was not matched between two Arxiv papers. Now, here is where we are. After these reviews, they never updated their data to solve this issue, but they decided to let other guys do their experiment instead of them. The easiest way to solve this is to plot the resistivity data again on a logarithmic scale. And this takes less than a minute because they have raw data. This is a very uncommon situation in the scientific community.

Re: Andrew McCalip demonstrates synthesis of LK99

#342

Post by cthalupa »

brakedam wrote: post #341
cthalupa wrote: post #338

Earlier quoted context omitted.

It would not be a normal part of the process for people to be demanding samples just because there was a preprint posted on arxiv. It's a weird situation and they don't owe anyone any of these samples. They say they want to share samples after they get a peer reviewed paper published. That's not a weird position to be in. If it wasn't for the hype around this, they wouldn't be in this position. Let the process play o…

This case is something different. Because everyone reviewed their Arxiv papers and found that there’s no meaningful figure for the resistivity. And even magnetization data was not matched between two Arxiv papers. Now, here is where we are. After these reviews, they never updated their data to solve this issue, but they decided to let other guys do their experiment instead of them. The easiest way to solve this is to…

Both papers were significantly rushed for reasons unrelated to the science aspect of it.

Wait for the peer reviewed paper if you are this concerned about it.

Re: Andrew McCalip demonstrates synthesis of LK99

#343

Post by Vecr »

nyospe wrote: post #325
MetaWhirledPeas wrote: post #286

Earlier quoted context omitted.

> Maybe I'm misunderstanding, where did withholding information come into this? When I mentioned gatekeeping I was specifically referring to how there's this formula that was kept secret since 1999. At some point the potential significance surely became apparent, and one of the only speculations I can come up with to justify that would be gatekeeping; keeping the information out of the hands of the filthy commoners f…

In 1999, I was still a student in solid state physics, not far past my bachelor's degree, and happened to notice the publication of something that, to this day, I suspect might be (note, load bearing "might") a critical breakthrough for desalination. Nothing came of it. Nobody has published any follow-up for it. Nobody has done any research that would contradict it either. It's just sitting out there, unnoticed, deca…

At least post the citation for the desal thing?

Re: Andrew McCalip demonstrates synthesis of LK99

#344

Post by mrguyorama »

OJFord wrote: post #43
est wrote: post #25

Earlier quoted context omitted.

It's made in USA baby!

I think you're joking, I'd 100% assume it, except that I ran into some truly bizarre US patriotism while trying to follow McCalip's updates a few days ago - last relevant one I could find was 'materials coming tomorrow' on 27th, but then I couldn't find anything about using them or any update. Just a decent into people tweeting (in thread) about how great America is, the best country, etc. Really surreal. Think it wa…

It's important to remember what kind of people are still invested in twitter enough to comment randomly on something they have no connection to.

Re: Andrew McCalip demonstrates synthesis of LK99

#345

Post by lr1970 »

ThePhysicist wrote: post #340
pnwcoder wrote: post #339

Earlier quoted context omitted.

What would be an explanation for the partial levitation of the LK-99 sample shown in the video?

Could be normal diamagnetism, or even ferromagnetism. Very hard to say as they don't even give any field strengths in the video, it's just a Neodym magnet they hold near the sample. If I understand the video correctly they just orient the magnet by hand, so I would not even rule out a ferromagnetic effect. There can be multiple regions with different orientation in such a polycristalline material, which can produce a…

> Could be normal diamagnetism, or even ferromagnetism.

I am curious how one could confuse the two? One leads to repulsion, another to attraction.

Re: Andrew McCalip demonstrates synthesis of LK99

#346

Post by _jal »

peteradio wrote: post #327
_jal wrote: post #242

Earlier quoted context omitted.

> To be fair, no one in the us has a grant to replicate something that came out this week And yet researchers in other countries managed to find the money this week. That would seem to point to a real relative weakness that's worth thinking about. Whether it is the result of gatekeeping, bureaucracy, academic squabbling, or something else, a cranky (and hilarious) Russian did better, faster work in her kitchen. Even…

Seems kind of stupid to do chemistry in your kitchen. What exactly is the rush here to come out with results right now ?!

> What exactly is the rush here to come out with results right now?!

Well, the work is happening right now.

You seem to want to make it sound like impatient kids being unreasonable or something, which is a ridiculous read.

It is more a matter institutions becoming irrelevant because they literally can't keep up with their peers. Which brings me back to,

> Seems kind of stupid to do chemistry in your kitchen.

When the institutions in your country become incompetent, that's what you're left with.

Re: Andrew McCalip demonstrates synthesis of LK99

#347

Post by ThePhysicist »

lr1970 wrote: post #345
ThePhysicist wrote: post #340

Earlier quoted context omitted.

Could be normal diamagnetism, or even ferromagnetism. Very hard to say as they don't even give any field strengths in the video, it's just a Neodym magnet they hold near the sample. If I understand the video correctly they just orient the magnet by hand, so I would not even rule out a ferromagnetic effect. There can be multiple regions with different orientation in such a polycristalline material, which can produce a…

> Could be normal diamagnetism, or even ferromagnetism. I am curious how one could confuse the two? One leads to repulsion, another to attraction.

I'm not even sure they reversed the magnet polarity in this video, it seems they just removed the magnet and put it back, so there's no way to rule out a ferromagnetic effect. Again, I just find it really hard to deduce anything from this footage, not saying it can't be a superconductor.

I'm not even sure they reversed the magnet polarity in this video, it seems they just removed the magnet and put it back, so there's no way to rule out a ferromagnetic effect.

I'm not sure either if LK-99 is a type-II superconductor but I would believe so given the papers I've read. Type-II superconductors aren't perfect diamagnets, they allow magnetic flux to penetrate the superconductor once you hit the first critical field, these flux vortices then get pinned at sites of defects where the energy requirement for breaking the superconductivity is lowest. That's what keeps a type-II superconductor levitating over a magnet, a type I superconductor or perfect diamagnet wouldn't do that. Then again I have never seen how e.g. a tiny YBCO flake (high Tc type-II superconductor) would behave if you put it in a beaker and dragged a Neodym magnet below it, so who knows.

Re: Andrew McCalip demonstrates synthesis of LK99

#348

Post by amluto »

To me, this doesn’t really look like the little sample is trying to levitate. It looks like it’s trying to rotate, almost like it’s trying to line up with the magnetic field.

Magnetic dipoles in a magnetic field experience a torque, and if a little sliver of stuff experiences a torque trying to make it point a particular direction, this could easily overcome the force pulling it toward the magnet.

(The torque on a dipole is proportional to the applied field. The force is proportional to the gradient of the field. And the experimenters seem to be using a pretty big flat magnet or a big solenoid, close to the center, which is likely to have a fairly spatially constant field near the surface.)

I’m reminded of once holding a bar magnet in a small plasma testbed electromagnet. Small = a few feet long and maybe 2 feet across. (The big one across the room was about the size of a semi truck IIRC.). I naively expected the magnet to be pulled in toward the center. Nope, not so much, but it tried quite hard to twist itself in my hands.

Re: Andrew McCalip demonstrates synthesis of LK99

#349

Post by imbawbe »

refulgentis wrote: post #192
lifthrasiir wrote: post #187

Earlier quoted context omitted.

You could have just requested more contexts then. You instead picked three particular phrases, which are actually least relevant parts of the linked article, and concluded (or appeared to conclude) that my article is not worthwhile to read. It might be, but I want it to be worthwhile to read and your reply had no hints to avoid that. Especially given that the very point of my article is about providing those contexts…

Darn, didn't expect this. :( I suggest revisiting this thread in a week.

[flagged]

Re: Andrew McCalip demonstrates synthesis of LK99

#350

Post by jiggawatts »

From what little I know of solid state chemistry — which is not a lot — I do know that when mixing powders that don’t melt, grinding them with a mortar and pestle is not generally good enough. A ball mill is much better, but still may not be sufficient. An even better approach is to precipitate both reagents out of solution together for nano-scale mixing.

I’d like to see this redone with a much finer grind and thorough mixing.

Didn’t Nile Red just get a ball mill?

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