Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A room-temperature superconductor? New developments

science.org

Post reply on HN
Print view View original

811–820 of 821 posts

Re: A room-temperature superconductor? New developments

#811

Post by kragen »

akkartik wrote: post #804
kragen wrote: post #803

Earlier quoted context omitted.

maybe, but it's not yet in the same league as math, writing, cooking, sewing, and electricity, in terms of its effects on human life i mean all five of those were probably prerequisites for it? maybe if the humans build torchships or nuclear-powered starships, or convert the electric grid to mostly nuclear, i'd agree, but those all seem far in the future

I'm curious: why sewing in particular? As opposed to say spinning or weaving or knitting?

it's surely debatable, but my thought was that sewing seems to have predated weaving (of cloth), nålbinding, especially knit and crochet, and probably even spinning, and it was sewing that enabled the humans to live outside the tropics

sewing without spinning or weaving still gives you tents and jackets (of hide or felt, at least). i think weaving without sewing only gives you floor mats. spinning without sewing gives you rope, which makes longer fibers than natural sinews, and thus lassos and lashing, but i think these are less transformative technologies than tents and jackets

i think the humans probably could have developed the fission chain reaction without spinning but probably not without sewing

https://en.wikipedia.org/wiki/Sewing_needle#Prehistoric_sewi... sewing: 50–61 kya or possibly https://en.wikipedia.org/wiki/History_of_clothing_and_textil... 170 kya

https://en.wikipedia.org/wiki/Hand_spinning#History spinning: 41–52 kya

https://en.wikipedia.org/wiki/Weaving#Archaeology weaving: 27 kya (cloth doesn't survive but its clay impressions do)

https://en.wikipedia.org/wiki/N%C3%A5lebinding#History nålbinding: 8 kya

https://en.wikipedia.org/wiki/History_of_knitting knitting: .9 kya

https://en.wikipedia.org/wiki/Crochet#Origins crochet: .2 kya

Re: A room-temperature superconductor? New developments

#812

Post by kragen »

kbenson wrote: post #805
kragen wrote: post #797

Earlier quoted context omitted.

mostly cartoneros recycle what the biz refers to as corrugated fiberboard, which most people call cardboard in english. it's made of paper and glue there are different kinds of paper, which require different recycling streams; cartoneros will accept some others but not all your talk about 'losing the thread' makes me think you are playing some kind of game where the objective is not to find out what the truth is but…

> refers to as corrugated fiberboard, which most people call cardboard in english. it's made of paper and glue ... there are different kinds of paper Isn't that exactly the point I just made? I'm confused as to why you're restating it. In English nobody is going to mistake someone that makes a statement about "paper" as talking about "cardboard", whether they're referring to corrugated fiberboard or plain fiberboard…

corrugated cardboard is made of paper, not an entirely different material; recycling cardboard is recycling paper. at this point i'm starting to question whether you've actually seen a piece of cardboard at some point or whether you're a large language model

certainly it is not the case that something that is commonly recycled will be scavenged for profit in all cases. even gold sometimes escapes recycling

Re: A room-temperature superconductor? New developments

#813

Post by kbenson »

kragen wrote: post #812
kbenson wrote: post #805

Earlier quoted context omitted.

> refers to as corrugated fiberboard, which most people call cardboard in english. it's made of paper and glue ... there are different kinds of paper Isn't that exactly the point I just made? I'm confused as to why you're restating it. In English nobody is going to mistake someone that makes a statement about "paper" as talking about "cardboard", whether they're referring to corrugated fiberboard or plain fiberboard…

corrugated cardboard is made of paper, not an entirely different material; recycling cardboard is recycling paper. at this point i'm starting to question whether you've actually seen a piece of cardboard at some point or whether you're a large language model certainly it is not the case that something that is commonly recycled will be scavenged for profit in all cases . even gold sometimes escapes recycling

> corrugated cardboard is made of paper, not an entirely different material; recycling cardboard is recycling paper

Did you actually bother to read what I wrote in my various comments? Much of it was devoted to explaining the difference in what it meant and when people say paper compared to what they mean when people say cardboard. Why do you think I talked about boards and chairs?

> at this point i'm starting to question whether you've actually seen a piece of cardboard at some point or whether you're a large language model

I could say the same for you, given your inability to follow what has been said across even a handful of replies.

> certainly it is not the case that something that is commonly recycled will be scavenged for profit in all cases. even gold sometimes escapes recycling

Which also wasn't my point. My point, again and put bluntly, is that some materials may exist in a space where it's not profitable enough to harvest for an individual but they are still recycled either because of subsidies or because efficiencies of scale can be brought to bear by a larger organization, or the combination of the two (subsidies for larger regional trash pickup companies that can also bring economies of scale to bear) which mean a material is recycled, even if not profitable for the common person. Another example would be items that are unlawful to discard of in the trash. There are various chemicals and materials that it's unlawful to dispose of in the trash in the U.S. (motor oil), meaning those items are taken to a recycling and/or disposal center even if there's no payment for doing so.

It's not about it escaping recycling because people miss it, it's about how both economies of scale and subsidies and laws that all go into whether something is recycled which affect that calculus beyond just whether it's profitable, and thus something being commonly recycled is not necessarily an indicator that it's lucrative enough to do so that the material will be harvested by people for profit.

Re: A room-temperature superconductor? New developments

#814

Post by kleer001 »

douglaswlance wrote: post #776
kleer001 wrote: post #484

Earlier quoted context omitted.

> Can I have my flying car now? I ditto the sentiment. But we don't want literal flying cars. Well, self driven flying cars. Humans have enough problems when they're driving on the ground on ground made for driving.

There are far fewer things to run into in the sky.

true.

However the failure cases at those heights and velocities are far worse. There's several orders of magnitude difference between an airplane license and driving license.

Re: A room-temperature superconductor? New developments

#815

Post by sheepscreek »

Beldin wrote: post #735
sheepscreek wrote: post #644

Earlier quoted context omitted.

But it is. A significant part of electronics engineering is dedicated to heat dissipation. So what do we stand to gain? At least a slight improvement in efficiency of transmission. And a huge improvement due to simpler heat dissipation needs. So this might mean way faster battery charging - like 500 miles worth of charge in 5 mins. We’re mainly limited by how hot the batteries get during charging.

We're about halfway there already, just by cooling: 250km in under 4 min (1). (1) https://www.tue.nl/en/news-and-events/news-overview/13-07-20...

This is incredibly exciting. The biggest hurdle as yet to mass adoption.

Re: A room-temperature superconductor? New developments

#817

Post by fifthace »

mitthrowaway2 wrote: post #548
ninkendo wrote: post #450

Earlier quoted context omitted.

I’m not an expert on this, but I think superconducting wires have an current limit, as a current flowing creates a magnetic field which the superconductor has to repel. I read that the paper states a very low current limit for LK-99, meaning it loses superconductivity once a very modest amount of current is passed through it.

It's hard to tell what the critical current density of LK-99 is, because their sample is porous and probably very impure. They measured the critical current they could pass through a sample, but the conducting cross-section is somewhat unknown. Its high critical temperature suggests that it should probably have a higher current capacity than other superconductors. That said, in the extremes, current density is also l…

Is there any indication of what the breakdown voltage of LK-99 might be?

Re: A room-temperature superconductor? New developments

#818

Post by frays »

shin_lao wrote: post #164
Ajay-p wrote: post #19

I still have a very, very hard time understanding what all of this means. Is there an easy to understand explanation for a room temperature superconductor?

Superconductor are more efficient at transmitting energy, here are some consequences: - Cheaper electricity transportation - New kind of batteries - Consumer devices that don't heat up as you use them - Simplifies the design of fusion reactors, which means we could have fusion sooner and cheaper - Probably lots of things we can't even think of If this is true, then you still have a lot of time before you can do indus…

Thank you for listing the consequences of LK99 / having superconductors available at room temperature.

Re: A room-temperature superconductor? New developments

#819

Post by internetter »

chrismorgan wrote: post #782
Beldin wrote: post #735

Earlier quoted context omitted.

We're about halfway there already, just by cooling: 250km in under 4 min (1). (1) https://www.tue.nl/en/news-and-events/news-overview/13-07-20...

I love that electric vehicle charging can be expressed in speeds (that is, distance divided by time). 250km/4min is 3750km/h, a touch over Mach π.

I like this. Woah, your car charges at 4000 kilometers a hour? Mine only does 3000!

Re: A room-temperature superconductor? New developments

#820

Post by Denote6737 »

mytailorisrich wrote: post #753
Denote6737 wrote: post #751

Earlier quoted context omitted.

If we can even get the charge times for EVs down to the minutes to take to refill ICE tanks. It will basically remove the range anxiety problem.

Best way to get EV 'refill' time to minutes is battery swapping. This already exists commercially, see Nio in China, and it apparently takes as little as 3 minutes. Similar speeds for charging are impractical because of the power spikes required even if the battery could take it. You cannot have instant charging, that's not pedantic, that's the discussion, and in any case there is a practical limit to how fast it can…

I personally don't have a problem with the current 30 minute charge. If you drive you should stop for 20 to 30 minutes every couple of hours.

What we need is sufficient infrastructure for ev charging.

Post reply on HN