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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?

#541

Post by [deleted] »

sebzim4500 wrote: post #478
Roark66 wrote: post #443

Earlier quoted context omitted.

Seriously, people should stop panicking about lead that much. You know there is this fairly common hobby people have, it's called casting bullets. With lead. I've done it, I know many people that do it regularly and they're all fine. Furthermore, shooting ranges are full of lead in the ground. The laws around here(Poland) require a cleanup by specialised companies every few years and a concrete slab to separate the l…

Yes lead in the ground isn't all that scary. Lead in your body is a concern. So don't blow lead smoke over your neighbors house.

[deleted]

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

#542

Post by kibwen »

hollerith wrote: post #508
kibwen wrote: post #504

Earlier quoted context omitted.

> if you can show that there's no way to do what you want to do with lead-free The bar is even lower than that. For example, bullets are still made of lead, not because it's necessary, but because it's cheap, and despite the fact that it contaminates the meat of the hunted animal with lead.

Tangentially, the US Army has completely stopped using lead in bullets. Their 5.56 NATO ammo has copper where the lead used to be (i.e., inside a brass jacket) which reduces performance because copper is only 2/3 as dense as lead.

Copper bullets date back to the 80s, they're not a new development. Copper bullets have higher penetration despite having less mass, which makes them better against armored targets, and NATO still held on to lead for so long just because it's cheaper.

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

#543

Post by KevinGlass »

marcosdumay wrote: post #293
obblekk wrote: post #150

The method to produce this material as described in the related paper [1] is fairly simple and could be done at home with a $200 home metal melting furnace from amazon and the precursors (which also seem to be fairly standard easy to obtain metals). If this is real, I'd expect some smart people from hackaday / youtube to reproduce this within weeks if not days. If this is real, it'll change society quickly and perman…

Ok, let me just add the obvious disclaimer: don't try this yourself unless you have a pretty good understanding of chemical lab safety. Really. It's more likely that you will contaminate your land, and possibly your neighbors land too than that you will manage to replicate it.

You are vastly overestimating the danger involved in this.

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

#544

Post by hguant »

hollerith wrote: post #508
kibwen wrote: post #504

Earlier quoted context omitted.

> if you can show that there's no way to do what you want to do with lead-free The bar is even lower than that. For example, bullets are still made of lead, not because it's necessary, but because it's cheap, and despite the fact that it contaminates the meat of the hunted animal with lead.

Tangentially, the US Army has completely stopped using lead in bullets. Their 5.56 NATO ammo has copper where the lead used to be (i.e., inside a brass jacket) which reduces performance because copper is only 2/3 as dense as lead.

Sorry, but this is entirely incorrect.

First, terms - brass is not used to "jacket" a bullet. Brass is used as the case material for the cartridge. Steel, and nickel plated steel are some times also used here. "Jacketing" (as in, Full Metal Jacket) refers to the material that wraps around the exterior of the projectile. As far as I'm aware, the material used here is almost always copper, or a copper alloy (cupronickel).

The US standard bullet is the M855. It's a lead core with a soft soft steel penetrator at the tip, that's jacketed with copper.

There's an advanced version of the M855, the M855A1, which is an entirely steel slug, jacketed with copper. This bullet has better terminal performance at longer ranges, and slightly better armour piercing capabilities.

The US army standard training round is the M193. It is a lead bullet jacketed with copper. Interestingly, it in many ways has better terminal performance than the M855 because this is the bullet the M16 and M4 rifles were designed around, and the M855 only exists because of NATO politics.

There are no bullets in the US inventory, to my knowledge, that use a copper core. Copper is simply far too expensive to be used at that scale, and, as you pointed out, reduces the weight of the projectile which has negative effects on terminal performance.

"Why are bullets jacketed in copper" you might be wondering here - when rifle cartridges were invented, they still used black powder, and all bullets were lead. When smokeless powder was invented, it became possible to have more explosive power per unit of volume. However, this had two negative effects - one, the lead projectile would either disintegrate, or became entirely inaccurate, at the speeds it was accelerated to. Second, the force of the bullet against the rifling of the barrel was rubbing away metal from the bullet, leaving lead deposits which fouled the gun and made it inaccurate. All steel bullets solved this problem, but increase the wear on the barrel. The solution was to coat (jacket) each bullet in a thin layer of copper, which was stiff enough to withstand the force of friction in air, while also softer than the steel barrel and reduced wear and tear on the rifles

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

#545

Post by civilitty »

aden1ne wrote: post #338
Maxion wrote: post #117

Earlier quoted context omitted.

The synthesis section honestly looks very simple, I would assume a simple ceramic kiln could be used? You just need PbO, PbSO4, Cu, and P powders.

The powdered lead seems like something you need to be careful with tho. Quite toxic.

No more or less toxic than the powders used to hand mix oil paints. Just buy a fume hood off ebay.

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

#546

Post by jacquesm »

jjoonathan wrote: post #527
serf wrote: post #483

Earlier quoted context omitted.

>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism. most of the common examples are in-the-works or exist in some form, they just don't satisfy the 'every-person' checkbox yet. AI? sure. Flying cars? sure. Robots? sure. Fusion is in the works, too. Tens of billions of dollars being thrown into t…

My favorite example is the hydrogen fuel cell. It was invented before the lead acid battery back in the 1800s. PEM gave it a boost around the Apollo era, but that wasn't enough to make it widespread either. Lead-Acid went through its whole 100+ year character arc and hydrogen fuel cells still haven't found product market fit. Sometimes that's how it is.

There are plenty of commercial applications of hydrogen fuel cells though. The biggest issue has been pretty much a constant over the time since it has been invented: keeping the membranes free from impurities is hard.

But there are all kinds of transportation devices using hydrogen in production today.

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

#547

Post by voldacar »

JoeMattie wrote: post #80
foxhill wrote: post #6

big if true. far from a chemistry expert here, but synthesis looks basically trivial (if you consider 10e-5 torr vacuum to be trivial), and the materials are readily available. hell, from the instructions alone i could probably make it at home. i mean the search space is unfathomably large, so i suppose it’s possible that something like this exists, but the paper quality itself doesn’t.. spark joy? :) i’ll maintain a…

I've made YBCO superconductors in my garage many times and the solid state synthesis method in the paper is very similar to that used by hobbyists. In fact, it seems to not require the usual careful slow annealing under flowing oxygen. I wouldn't be at all surprised if even simpler methods are feasible. For instance, there's a rapid synthesis method for YBCO that uses a small alumina boat, some glass wool, a resident…

If you make LK-99, I would love to buy some from you. Email me if interested

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

#549

Post by Tuna-Fish »

inasio wrote: post #294
Tuna-Fish wrote: post #183

Earlier quoted context omitted.

Previous improvements in high-temperature superconductors already made it possible to build a MRI machine using LN2 instead of LHe. I think all existing operational units still use LHe, but using LN2 has been demonstrated in lab conditions, and the next generation of machines will almost certainly use it instead of helium.

Or maybe not anymore ...

It takes a long time to validate new stuff for medical devices. Even if this discovery completely pans out, there will be two or three generations of MRI machines based on LN2-cooled superconductors.

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

#550

Post by downvotetruth »

lopuhin wrote: post #428
blobbb wrote: post #306

Earlier quoted context omitted.

filed 2022-08-25

I think it's even from 2021-08-25, see https://patents.google.com/patent/KR20230030188A/en?oq=WO202...

2 years after the patent application and 4 months since publication and not involving any lab an author is not apart of to replicate a process that should take a week - a reason to wait for seems hard to justify.
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