In summary, "Fucking magnets, how do they work?" https://www.youtube.com/watch?v=_-agl0pOQfs
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LK-99 isn’t a superconductor
331–340 of 754 posts
Re: LK-99 isn’t a superconductor
#332my only criticism is to the people who, without real background in the area, read the paper, thought the synthesis was "easy", raced to get the reagents only to realize that you can't easily order somet things without a prior relationship and trust with a chemical supplier, and then showed some antimagnetism in their shitty examples, without understanding that that phenomenon isn't conclusive evidence. It's sort of an example of the "why don't you just...." phenomenon where a noob tells an expert that solving a problem is easy...
I guess I also criticize whomever published the original paper. They did just a bad enough job to get people excited, but experts pretty quickly noticed major flaws in the article which cast enough doubt to pretty much reject even attemptiong a replication.
Well, i suppose to be fair, I should also criticize the theorists who came out and made crazy claims saying that theory supports this being a superconductor- Konerding's 27th law, amended, says: "Given a ridiculous experimental claim, there will always be at least 3 theorists who publish a paper saying that the theory supports the claim".
Anybody who lived through Fleishman and Pons (and fusion in general) has learned to be highly skeptical, up front, and the expectation is that the publisher/author of the article has done an excellent job making their findings reproducible.
Re: LK-99 isn’t a superconductor
#333In their preprint, the Korean authors note one particular temperature at which LK-99’s showed a tenfold drop in resistivity, from about 0.02 ohms per centimetre to 0.002 ohms per cm. “They were very precise about it. 104.8ºC,” says Prashant Jain, a chemist at the University of Illinois Urbana–Champaign. “I was like, wait a minute, I know this temperature.” The reaction that synthesizes LK-99 uses an unbalanced recipe…
When I first saw the quoted resistivity, 0.002 ohms per cm, my thought was "this is not even a conductor, let alone a superconductor". 0.2 Ohms/m is several orders of magnitude less conductive than most metals, and solidly in the semiconductor range.
Right? That's what's not clear to me either. If they got readings for superconductivity and Cu2S impurities were the cause then fantastic, Cu2S is the room temperature superconductor? Just get a load of that instead then.
Or perhaps the way they measured the whole experiment was completely inane from the start if a simple conductor passes with flying colours. With that and them presenting ferromagnetism as the Messner effect makes me kind of question the competence of the entire analysis.
Re: LK-99 isn’t a superconductor
#334It’s disappointing news but the excitement and amount of replication on this paper was pretty fun to witness and experience. To me the most interesting part was everyone talking about potential consequences, uses, the order of magnitude improvements we’d see in certain costs or areas. Pumps, MRIs, power grids, chips, etc. Great reminder what materials science can do to some underlying economics.
I disagree. I get pissed off when revolutionary scientific news is brought to me only to turn out to be some bogus crap. I don’t care about the replication and peer review process, it’s not fun, it’s banal. I would much rather have preferred to learn about LK-99 once it was confirmed to be a room temp superconductor, and if it wasn’t then I’d rather never hear about it. Now I have to walk back explanations I gave to…
> "Now I have to walk back explanations I gave to various people and explain LK-99 actually isn’t special at all. I will look like a god damn idiot."
Y'know those stories on Reddit about people's awful childhoods, like "I needed the toilet in a shop and my parents told me to be quiet, and then when I pissed myself, my dad dragged me outside and beat me for 'embarrassing him'"? Have you noticed the dad comes out of the story looking bad for prioritising his image? Saying "I don't want to tell this to people because then _I_ will look bad" already makes you look bad.
I told my dad LK-99 isn't a superconductor and he said "that's a shame, oh well, exciting while it lasted".
Re: LK-99 isn’t a superconductor
#335This was absolutely a fun and worthwhile experience for everyone involved. A lot of people got more interested in current materials science because of this. We watched a large community spring up out of nowhere to investigate a new discovery. It was really an incredible thing to witness, and I see only good things came of it. I can't really understand the sour grapes commenters in this thread. Not sure if they just w…
For me personally it is just general (mild) annoyance with a community that somewhat consistently likes to think it is smarter and better than others and which is then only ever willing to admit they were wrong in roundabout ways like "well this was all fun, anyone who thinks it was a waste of resources or what-have-you doesn't see how much impact it had". You can see this wild speculation play out _commonly_ for lot…
Who really knows _that_ much about anything though? Few people are experts in a given topic. Although I see your point, I suppose more people would be good to recognise that, especially about themselves.
That said, this is a fairly general forum and (mostly) for entertainment purposes right?
Re: LK-99 isn’t a superconductor
#336Earlier quoted context omitted.
One of the papers that argued that LK-99's levitation was due to mixed diamagnetism and weak ferromagnetism also assigned it a very strong diamagnetism: -2•10^-4, which would make it the second-strongest such material known, beating out bismuth. Probably not that useful, but interesting if confirmed. I read some of the papers linked in this article, but they use different units and don't identify a diamagnetic suscep…
But, a lot of those studies weren't using pure LK-99 but samples with lots of copper sulfide mixed in.
Copper sulfide's diamagnetism is not that high. It would be notable if it were. So that isn't a possible explanation. Cu2S was suggested as a culprit for the observed conductivity changes.
The preprint reporting the high value of diamagnetism is here:
https://arxiv.org/pdf/2308.03110.pdf
>The subtracted diamagnetic susceptibility is larger than that of Bismuth and water but smaller than that of Pyrolytic carbon (page 3, bottom left)
Re: LK-99 isn’t a superconductor
#337A good time to remind everyone that for almost 2 decades now it's been determined that the majority of published scientific findings are wrong. [0][1] Including possibly even the very determination that the majority of published scientific findings are wrong.[2] ([3])
So, if that's the case, when a new result comes out, the appropriate reaction is to assume there's a better than average likelihood it will be refuted. And honestly that's what makes science great. Unlike with some other fields of human endeavor, it is possible to firmly refute bad science. And often learn something new in the process.
[0] https://journals.plos.org/plosmedicine/article?id=10.1371/jo... [1] https://www.annualreviews.org/doi/10.1146/annurev-statistics... [2] https://replicationindex.com/2019/01/15/ioannidis-2005-was-w... [3] https://en.wikipedia.org/wiki/Epimenides_paradox
Re: LK-99 isn’t a superconductor
#338A good time to remind everyone that for almost 2 decades now it's been determined that the majority of published scientific findings are wrong. [0][1] Including possibly even the very determination that the majority of published scientific findings are wrong.[2] ([3]) So, if that's the case, when a new result comes out, the appropriate reaction is to assume there's a better than average likelihood it will be refuted.…
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Re: LK-99 isn’t a superconductor
#339This was absolutely a fun and worthwhile experience for everyone involved. A lot of people got more interested in current materials science because of this. We watched a large community spring up out of nowhere to investigate a new discovery. It was really an incredible thing to witness, and I see only good things came of it. I can't really understand the sour grapes commenters in this thread. Not sure if they just w…
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Re: LK-99 isn’t a superconductor
#340Earlier quoted context omitted.
I think the story might be more complicated than that, I remember reading that the "third party" was the one paying the bills for the experiment so pushing it out early and even publicly failing would've been preferable to getting it dragged out infinitely for an unlikely hope of it being successful.
This funder-rushed science exactly what created Doc Ock and the Green Goblin.
Is this the origin of "semi-magnetic-man"?