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The first room-temperature ambient-pressure superconductor?

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

#591

Post by harry8 »

pohl wrote: post #458
thehappypm wrote: post #401

Earlier quoted context omitted.

They've just proven (if true of course) that it's possible at all. That is a massive, massive leap. And once it's possible, it won't be long until it's optimized. We've seen this everywhere -- transistors were once huge and now nanometers; solar cells have improved in every where; batteries are cheaper and better than ever.

I was with you on the first part. If this proves room-temperature/ambient-pressure is possible at all, that is huge. Not so sure about the "won't be long until it's optimized," though. 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.

"I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism." --Pohl Longsine

Nice phrase, useful many places and I might well do that. (Unless objections are raised).

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

#592

Post by achr2 »

lilgreenland wrote: post #572
sudosysgen wrote: post #426

Earlier quoted context omitted.

Ah, that's not the video I saw. I was referring to this one : https://sciencecast.org/casts/suc384jly50n

well that one looks great. Maybe in the original video a superconductive effect was there, but not strong enough to frame lock. But you can see it in the newer video.

The new video doesn't show anything convincing either - Pyrolytic graphite behaves the same way at room temps due to strong diamagnetism.

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

#593

Post by eterevsky »

rwmj wrote: post #78
eterevsky wrote: post #51

Earlier quoted context omitted.

> 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.

This (or something derived from it) would be used for power delivery literally everywhere in the world. It might well be bigger in scale and volume than all the computers.

I think it would still change the world less than computers have changed it. Without computers we wouldn't have this conversation. So much in the modern world is basically impossible without computers.

Superconductivity will for sure enable some innovations and could change how we are building power grids, but I don't see it changing the world to the same extent.

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

#594

Post by Tuna-Fish »

kibwen wrote: post #542
hollerith wrote: post #508

Earlier quoted context omitted.

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.

They date back further than that. In WW1, French troops were mostly shooting full copper/bronze shot. The reason was that it was cheaper and easier to mass-produce solid copper bullets than it was to increase the production of jacketed bullets by a similar amount, and with Germany excluded from naval trade, there was suddenly a lot more copper available on the market.

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

#595

Post by scarmig »

arjvik wrote: post #517
nick__m wrote: post #506

Earlier quoted context omitted.

Superconductivity is not enough for a cpu that doesn't generate heat, you would need a cpu built of reversible logic gate. Thermodynamics requires that when you destroy a bit of information you generate at least 2.9×10−21 J. It's the Landauer's principle.

Say we use this (or any other) superconductor to build an AND gate. Assume one input is zero, so the information of the other input is lost. I assume the energy lost as heat occurs due to the "current" going into the and gate having "nowhere else to go" other than to dissapate as heat? If that's the case, simply redesigning our logic gates to have as many outputs as they have inputs, with some of these outputs feedin…

It's a thermodynamic argument. Suppose you have a system of n bits each in an arbitrary state, so it has 2^n microstates. You set one bit to 0, regardless of what it was originally. It now has 2^(n-1) microstates. Finding entropy S for a given number of microstates N, S = k_b ln N, and so dS = k_b * (ln 2^(n-1) - ln 2^n) = k_b * ln 2 * (n - 1 - n) = -k_b ln 2, i.e. entropy has decreased by a constant amount. But by the second law of thermodynamics, entropy cannot decrease in a closed system, and the way it's dissipated is as heat. How much heat has been released? dE = T*dS, so dE >= k_b * ln 2 * T. Note the dependence on temperature: you can reduce how much heat is released by having it operate at a lower temperature. Even at room temperature, however, this is a billion times less than existing heat dissipation, so there's lots of room for improvement before we start hitting the Landauer limit.

This can be worked around by introducing ancilla bits to maintain the number of states in the system, but the instant you destroy the ancilla bits (e.g. by feeding them back to the power source), you dissipate energy. The exact mechanics of this would depend on the implementation of the device you're talking about, but you'd inevitably encounter it and be unable to overcome it.

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

#596

Post by arcticbull »

Turskarama wrote: post #574
jacquesm wrote: post #546

Earlier quoted context omitted.

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.

Sure, but the point is that they hardly caused a revolution in energy storage. If fuel cells didn't exist, for the average person life would be exactly the same. Revolutionary tech does change normal peoples lives, and sometimes very rapidly, but a lot of stuff that looks revolutionary just kind of never works out. I'd say nuclear power is probably the prime example of this. It was supposed to bring us electricity to…

> It was supposed to bring us electricity too cheap to meter, but it's actually the most expensive form of generation that anyone bothers to build.

Hardly, coal is much more expensive if you price in the externalities. We just pretend they don't exist for coal, and we staple anything that moves to nuclear.

Coal kills 25 people per TWh generated, and the actuarial cost of a death is about $10M as used by the nuclear industry, not to mention the environmental costs. That means the all-in cost of coal is much much higher than the LCOE - about 16c/kWh according to the Government of Canada. [1] The 2019 US EIA LCOE for nuclear is about 7.7c/kWh. [2]

Nuclear is cheaper than coal and costs around the same as solar/wind + storage - less, depending on the desired level of equivalence between the two. It has high up-front capital costs and a long payback period so the cost depends primarily on cost of capital. Fuel costs are $0.015/kWh to $0.00015/kWh in uranium.

There are places that get lots of cheap, reliable no-carbon power from nuclear. For instance Ontario, at about $0.10CAD/kWh ($0.075USD/kWh), delivered. [3]

[1] https://natural-resources.canada.ca/sites/www.nrcan.gc.ca/fi...

[2] https://en.wikipedia.org/wiki/Economics_of_nuclear_power_pla...

[3] https://www.cer-rec.gc.ca/en/data-analysis/energy-markets/pr...

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

#597

Post by ClumsyPilot »

jacquesm wrote: post #587
Turskarama wrote: post #574

Earlier quoted context omitted.

Sure, but the point is that they hardly caused a revolution in energy storage. If fuel cells didn't exist, for the average person life would be exactly the same. Revolutionary tech does change normal peoples lives, and sometimes very rapidly, but a lot of stuff that looks revolutionary just kind of never works out. I'd say nuclear power is probably the prime example of this. It was supposed to bring us electricity to…

Fuel cells are just another transformer like the dynamo, or any kind of motor. They turn one kind of energy into another and in the context of hydrogen (which you could produce out of water using electricity as a means of storing energy) it serves to reverse the storage step. This is nice to have but just like nuclear power it's a variation on stuff that we already have, it is at best a quantitative change (and hopef…

> This is nice to have but just like nuclear power it's a variation on stuff that we already have

By that logic a super conductor is just a variation of a conductor.

Nuclear power is more distinct from burning coal than any superconductor is distinct from copper wire.

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

#598

Post by akasakahakada »

jcranmer wrote: post #177
akasakahakada wrote: post #92

Earlier quoted context omitted.

People use the same stupid argument when commenting on quantum computer. But in case of QC, one is powerful enough to compute everything and we might not even need two, except for spare. Say a 1000 qubits QC exist, Work that it can do is the sum of all computering power in human history. You cannot even verify if the result is right or not because simply you don't have any classical alternative for that workload.

> But in case of QC, one is powerful enough to compute everything and we might not even need two, except for spare. Say a 1000 qubits QC exist, Work that it can do is the sum of all computering power in human history. You cannot even verify if the result is right or not because simply you don't have any classical alternative for that workload. A 1000-qubit QC can't break a RSA-2048 key, let alone a lot of other inter…

1000-qubit QC can't break a RSA-2048 key

Neither any classical computer can. We don't even have enough harddrive to store all quantum information in a 100 qubit QC, let alone 1000qubit. QC is limited to solve a subset of problems do not automatically equals to QC is useless comparing to classical ones. Also not able to invalidate the powerfulness of QC beyond 100 qubits.

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

#599

Post by bradleyjg »

willis936 wrote: post #536
gerdesj wrote: post #498

Earlier quoted context omitted.

When I were a lad ... I remember the first superconductors (long predicted) being announced in the mid '80s. They stayed high on the nerdy headlines for quite a few years. Excitable write ups in New Scientist for us civilians. Nuclear fusion was still 50 years off but room temp superconductors were only a few years off (nope). I went to a posh school in Oxfordshire in the mid to late '80s and my physics class (form)…

Those mid 80s high temperature superconductors are now mass produced for NMRs and fusion startups. I don't think it's given that all superconductor breakthroughs will require 40 years to get to that point and there's good reason to believe they won't (startup penalty, industry bootstrapping, market finding, etc. have all been completed).

Those mid 80s high temperature superconductors are now mass produced for NMRs and fusion startups.

As alluded to those same pop science magazines promised a fusion future too. Here we are, magazines extinct, with fusion startups using LN2 superconductors. Also: no quantum computers, no space colonies, no flying cars (or even supersonic planes), and twitter/reddit/facebook are worse than Usenet.

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