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High-Temp Superconducting Tape
DrLudicrous writes "The NYTimes is running a little overview of the current state of mass produced superconducting materials. A company named Superpower (another blurb on them here) is making a layered superconducting tape out of ceramic materials- ceramics that are high-temperature superconductors (no resistance at liquid nitrogen temperatures, 77K). This is much cheaper to maintain than technologies based on superconducting metals, which tend to require liquid helium (~4 Kelvin) temperatures. A note of contention: the article mentions that superconductivity is not well understood -- high-temperature superconductors are not, but classical 'low-temperature' superconductors are well-described under the Bardeen-Cooper-Schrieffer (BCS) theory."
Man! We had that when I was in high school (late `80's)
Looks like room temperature superconductivity is impossible. Have we made any progress in new superconducting materials in the last 15 years?
You could convince the nuttier audiophiles to wire their speakers with it.
Fascinating stuff, but some of what's in the article really makes me grit my teeth. I love this bit:
Even now, they have yet to develop a comprehensive theory to explain its appearance in materials as diverse as metal and ceramics.
Such scientific conundrums are of only passing interest at Superpower, a four-year-old subsidiary of Intermagnetics General, and at other companies like it. After years of false starts and setbacks, these companies say they are closing in on the goal of producing relatively inexpensive superconducting wire for power generators, transformers and transmission lines.
Success requires making yard after yard of wire, and eventually mile after mile. The focus at the companies, at national laboratories and at many universities is on questions that call for a genius more like Edison than Einstein.
Uh, bullshit. If they don't understand how it works, they're never going to move this stuff beyond the applications possible at liquid nitrogen temps. I'm not selling that short -- it's neat, and has a number of industrial applications -- but we're not going to be making power lines, or even wiring our houses, with that kind of cooling.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
(Thorugh got the FP... ;-( )
Please mod accordingly...
Paul B.
That floating magnet experiment/demonstration they describe is one of the coolest physics phenomena I've witnessed, for those without subscriptions you chill the superconductor below its critical temperature and place a small magnet with high magnetic field strength to mass ratio above the superconductor and it floats or sits in mid air spining slightly, pretty cool to see.
This article is low on actual content, it fails to even mention what the Tc is for this tape. The highest Tc I'm aware of is in the 130K while room temperature is on the order of 300K. If we can find materials with high enough Tc and without bad qualities it will revolutionize the world, imagine an electric motor with near zero resistance, unfortunately it could be used for evil too.
That's just a matter of cost.
The article states that "Superpower's next generation tape has a pre-mass production cost of $50 kA/m". That's $50 for a meter of wiring able to carry 1000 amps.
Hardly a neglible current, though cost is probably hundreds of times more than equal current carrying capacity with copper wire.
Maybe he is wrong, but he isn't a troll. People like you, who moderate everything they don't like or disagree with as "troll", are the real problem on Slashdot.
If you disagree with the guy, make an informed, well-reasoned response, instead of the bullshit you actually wrote.
Electrons are not bled out of materials as the temperature decreases. In semiconductors they do indeed become less mobile, increasing resistance, but in true conductors they become more mobile, as there are fewer lattice vibrations to get in the way (a simplistic metaphor, of course).
At extremely low temperatures the electrons pair up, which leads to superconductivity in metals. The amount of power which can be transferred is very high. These pairs are very easily broken apart, which is why superconductors are not perfect reflectors, any light breaks the pairs. IIRC it also limits the power that can be transferred over a superconductor.
-Yarn - Rio Karma: Excellent
Where did you get the weird (and completely incorrect) belief that 'electrons get bled out of materials as the temperature decreases'?
I don't know what you mean by bloody electrons (is that a British thing?).
As far as potential applications - they are numerous. Without thinking very hard a couple came immediately to mind.
(1) Electro-magnets - there are a lot of applications in medical and theoretical physics that require strong magnetic fields. Assuming that high-temp superconductors can be found whose properties don't break down under higher magnetic fields, superconductors could be used to create magnets stronger than any that we currently have.
(2) Particle detectors. If you have a superconducting loop and a charged particle passes through it, it will induce an EMF on the loop, causing a current to circulate. Since there is no resistance (i.e. no signal degradation), the current is much easier to detect and measure.
(3) MagLev anyone? Not on tape I guess, but levitating trains would be really nice. Then again, the previous ideas probably don't work very well with tape, but anything that helps move the field forward is bound to help.
I'm sure there are plenty of more interesting applications than these.
Let's go Hurricanes!!! 2006 Stanley Cup Champions!!!
That's what I read that as anyway.
Hundreds of times more? Not even close.
High Tc superconductivity actaully has the begginings of a good theory to explain it.
In BCS theory, electrons interact with phonons (lattice vibrations) to coordinate into pairs and form bosons.
In much the same way, electrons in high Tc superconductors interact with spin waves in an antiferromagnetic material to coordinate into pairs and form bosons.
An antiferromagnetic material is one where the magnetic moments of neighboring atoms are opposite
up down up down up down up down up
You could imagine trying to move the middle electron over one position (trade with the electron to its right):
up down up down down up up down up
Now our magnetic order is screwed up, and this defect can propogate:
up down down up down up down up up
Each pair of "up up" or "down down" next to eachother is a spin wave, which is a boson, with a spin of 1.
Of course, really proving this theoretically is much harder, I don't think it's been done in 3D.
Not sure what you mean. I agree the grandparent post was wrong. Starting from 12-guage 3-wire romex I get $20 kA/m for copper, but I'm not sure I did the math right.
Interesting. Is copper really that expensive?
Or was that retail price for a small quantity, and you'd get it for some fraction of that if you ordered a few km of it?
(Not expecting a reply from an AC poster, but perhaps someone who happens to read this knows about the stuff too.)
Interesting. Is copper really that expensive?
... and they have, actually. Copenhagen was the first, if memory serves. All of them quoted the capacity increase without digging as being the main reason. Per kA, it's probably more expensive, but the costs savings from not digging will probably make it cheaper over the lifetime of the cable.
Yes, actually. It's about $20-25/kAm right now.
But it's the recurring cost that's a big deal: at kiloampere levels, the power burned off by copper resistance starts to become more expensive than the cost of cooling. Since superconductors have strictly zero resistance, the cooling cost is fixed as the current scales, whereas it's linear in copper. At some point it becomes more economical.
The problem with high-Tc superconductors is that they have a current limit as well, and it's quite moderate, so the scale isn't quite there yet, when you work out all of the factors involved.
There are other reasons to switch, though: simply physical size: in Detroit, where they're replacing copper with superconducting cable in a few areas, they're replacing 18,000 pounds of copper with 250 pounds of superconductor - they replaced 9 cables with 3, and left 6 empty cable lines. This gives them 3 times the energy capacity without having to dig new cable lines at all.
The capacity issue is really what's been driving cities to replace them, though - digging new power lines, especially in cities, is simply ludicrously expensive, and so any option to replace with higher capacity lines without digging is a win.
So yes, really, they will replace copper with superconductors
Tau's Law: Any sufficiently clueless claim is indistinguishable from a troll.
Time is Nature's way of keeping everything from happening at once... the bitch.
Yes, actually. It's about $20-25/kAm right now.
I just looked up the copper wire tables in my copy of Standard Handbook for Electrical Engineers - 1kA requires a 700mcm (mcm = 1,000 circular mils (cmils), 1 cmil is the area of a circle 0.001 inch diameter). That cable weighs about 2.2 pounds per foot, so a 1 meter long cable would be about 7.5 pounds. The latest price for copper was a bit less than $1.20/lb - so we're looking at $9/kAm.
The resistance loss with copper can be an issue, but you need to balance it against the refrigeration requirements for supercon's.
Probably the biggest commercial success for superconducting wire has been for NMR magnets - especially for MRI use.
A Shadeless room is a brighter room.
Say, did you know that you don't have to hit the return key when you reach the right-hand side of the text entry box?
Your text will automatically wrap around to the next line!!
Yes, it's true; it really, really will!
Isn't technology wonderful?
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Do a search for "copper kAm" and you'll find the $20 /kAm figure. You're neglecting a ton of the production cost, and considering the *raw* copper cost is just $9/kAm, an additional $10/kAm for the rest of the cable is entirely reasonable. They don't just lay bare copper in the ground, after all. Most of the HTS figures they give show the rest of the cable costing about $10/kAm as well.
The $50/kAm figure for HTS cable is the final cost for the full cable, ready to lay in the ground.
As for the resistance loss vs refrigeration requirements, it's important to remember exactly how cheap liquid nitrogen is. *Very* cheap. In fact, going much higher in temperature really isn't economically important! I haven't seen any figures on "maintenance cost", but considering the resistive losses for copper can be large (at 1000A with the resistance of copper for a 0.8" diameter cable being ~0.02 ohms/1000', you're talking roughly 60W lost per meter) the refrigeration costs are going to be quite manageable.
Up up, down down, left right, left right, B, A, Start