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Diamonds As Room-Temperature Superconductors
Stormalong writes "This article describes research into using diamonds as room-temperature superconductors. If successful, perhaps one day you could give your love a diamond engagement CPU instead of a ring!"
SciFi Today ran this story a couple of days ago with LOTS of interesting extra links here.
Room temp superconductivity is nifty. What's (literally) incredible is that the guy is claiming to have produced "Bose-Einstein-type condensate" at room temperature, as opposed to the usual few-billionths of a degree above absolute zero.
I find "experimental error" to be far more plausible, but of course it's hard to know without seeing both the original researcher's work as well as third-party confirmation results.
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The single most important development that would come out of a room-temperature superconductor would be the elimination of batteries, fuel cells, gas tanks, and every other such power storage technology.
Because a superconductor conducts with literally zero resistance, you can create a ring of superconducting material, pump as much current into it as it will tolerate, and just let the current cycle forever. No degradation whatsoever. Then when you want power, you just tap into the ring and pull it out on demand. Superconducting rings are real devices, by the way -- they're just big and expensive and require cryogenics.
If we could make them out of something that operated at room temperature, then we could (probably) make very small superconducting rings, and if the power density were high enough, we could use them instead of batteries or fuel tanks. And they would never, ever wear out, no matter how many times you charged or discharged them. The amount of power they could contain is dependent on the superconducting material in question, but a high-power-density room-temperature superconductor (if such a thing is possible) would eliminate all of mankind's power storage and transmission problems. The only concern left would be generation.
ZFS: because love is never having to say fsck
They glow because they're doped--rubies were shown on a PBS show a few years back. Lab created gems are generally doped with elements to make them distinguishable somehow--don't think scientists and engineers don't get bribed to produce a perfect gem.
Yes, single crystal 'gems' created in the lab are for all intents and purposes, perfect, they have to be to be used in any experiment concerning the creation of semiconducting devices.
It probably would NOT change the gemstone market due to cost of growing diamonds. IIRC, CVD (Chemical Vapor Deposition) is currently the only way to produce diamonds for manufacturing. This is in no way as cheap or easy to do is pulling a 'perfect' silicon ingot out of a molten bath.
So, when's lunch?
Remember, the next time you buy a diamond for your sweetie, slave (and probably child) labor, blood, sweat and tears literally goes into each one. Ahh...nothing says love like the suffering of your fellow man. If this concerns you, then you should probably buy Canadian Arctic Diamonds which are exploitation- and conflict-free.
This is known as Wiedeman-Franz Law in Physics. It describes the relationship between eletron heat transfer and conductivity. However it is only valid for Metals. Heat transfer in semiconductors is dominated by lattice vibration transport. Due to the bandgap there is little phonon/electron interaction.
A notable exception is diamond with a low electrical conductivity on the order of 1 S/m and a high thermal conductivity of 700 W/mK.
Its not an exception, its a semiconductor with a large bandgap and behaves exactly as expected.
Yikes. If you try to "tap in" to an inductor, it will produce an enormous voltage and immediately arc to close the circuit. The only way to get energy out of a superconducting solenoid is through some magnetic interaction.
If you pick the number of windings carefully, tapping directly into the inductor works just fine.
The inductor wants to maintain the current flowing through the coil. If that is the amount of current you expect to draw for your load, both load and coil will be perfectly happy in the new configuration. If you wish to draw less current (or tolerate interruptions without arcing), drop a resistor in parallel with the load. This will limit voltage across the load to the amount needed to push the coil's current through the resistor.
When you aren't using the load, of course, you short across it so as to reduce resistive power loss. Typically this switching is actually performed by having a closed coil, and heating the part you want to cut out above the superconducting breakdown temperature, if I understand correctly.
The only design difficulty is that this requires a large number of windings (sheet current is typically millions of amps or more, which means you need millions of windings for a load that draws 1A).
Did you know that the entire U.S. electrical grid could be powered by less than 150,000 modern wind turbines?
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I did not know this, so I did some quick googling and found some interesting numbers. According to the DOE the total U.S. generation of electricity for 1999 was 3691 billion kilowatt hours.
http://www.eia.doe.gov/cneaf/electricity/epav1/
According to the Danish Windpower Industry Association, a modern wind turbine will generate about 2 to 3 million kilowatt hours of electricity per year.
http://www.windpower.org/faqs.htm#anchor727849
If these numbers (and my math) is right, your conclusion is off by about an order of magnitude
Uh, What?. Synthetic gemstones are chemically indistinguishable from the real thing. For a while, the distinguishing characteristic of lab created gemstones was their remarkable lack of defects. However, enterprising companies that make synthetic stones have figured out how to include the defects that you normally see in natural stones. So you can no longer tell the difference. There is no law to require they be marked, and there is no inscentive for the manufacturers to do so. If you saw stones that glowed, they were probably made that way for industrial use. Ti-doped Sapphire (Al2O3) is used for "tunable" lasers, for example. In fact, the first laser was made from ruby (Cr-doped Sapphire). These days people can make synthetic sapphires the width of a telephone pole and several feet long. They are used as windows on the barcode scanners in the supermarket because sapphire is much more scratch resistant than glass.
Frankly I don't understand why people value stones that were dug up out of the ground more than ones created in the lab. It's not like there is a real difference. Besides, if you actually visited a gemstone mine, you would probably lose all the romantic ideas you have about the origin of the stones.
As far as synthetic diamonds go, there are several possible ways to produce them. CVD is commonly done to produce diamond films for research. GE Superabrasives produces industrial diamonds using a high pressure process for decades. The diamonds are small, but they are cost effective. GE also produces "clarity enhanced" diamonds. They take natural diamonds that are lousy color and treat them to make them a more appealing color. Can you tell? I doubt it.
I'm a materials scientist, and I suspect that synthetic diamonds are less than a decade off. When that happens, the whole house of cards that is the diamond industry will come crashing down. Diamonds are not rare, but DeBeers controls most of the supply. When they loose that control, diamonds will crash to a price befitting their rarety.
And don't go around thinking that diamonds have ever been a good investment. The vast majority of diamonds actually depreciate relative to inflation.
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The internet is the greatest source of biased information in the history of mankind.