I went to your first link, and found no superconductors that operate over 140-160 degrees Kelvin, even under high pressure. Room temp is 295 Kelvin. Another of your links, Futurescience.com has superconductor kits that state this:
"All superconductor kits require liquid nitrogen. Do not order these superconductor kits unless you know how to obtain and handle liquid nitrogen." Several other of your links don't work.
I cut-and-pasted an article here from
www.sciencenet.org.uk/database/Physics/0003/p01422d.html
Here's the article from ScienceNet.(copyright 2003)
Question:
Is it true that superconductors have been developed that work at room temperature, but they are not being used so as not to upset the global economy?
We contacted a number of experts regarding your question on superconductivity. Here’s what they have to say:
“Well, no! The maximum critical temperature is still around 120K, with no real sign of increasing. Any scientist would be guaranteed instant fame and fortune, including a Nobel Prize, for discovering such a superconductor. No one would keep it quiet out of a (misplaced?) concern for the global economy. There is no example in history and many counter examples. Besides, it is not obvious that it would have such an effect!”
“The highest temperature superconductor is a mercury based cuprate with a Tc of about 140K rising to 160K under high pressure.
Practical superconductors using the new high temperature superconductors are all based around YBa2Cu3O7- and Ytrium based cuprate with a Tc of 90K. This is because enough material science work has been done to be able to manufacture wires and thin films which carry large currents.
These are being used already in microwave applications for high Q resonators- particular for the communication industry. They are also being used in wires for some power applications.
Along side the development of high temperature superconductors has been the development of low cost refrigeration units using the Joule-Kelvin effect which can cool large volumes to below 100K....this is to make the superconductors economically viable.
If there is a high temperature superconductor with Tc at room temperature there would be no reason to keep it a secret unless you were developing it for applications and wanted to keep it under wraps until you had solved the immense problems of turning a new material into a useful material.”
“Before 1986, the 'record high' for a superconducting phase transition temperature was 23.2 K (-249.8°C) for a material based on Nb3Ge (in 1973).
Since 1986, the record highest reached superconducting transition temperature has been ~135 K (-138°C) for a Mercury based material. To date this temperature has only increased to a maximum of ~158 K (-115°C). However, this temperature was achieved by placing the material under a large pressure.
So called commercial high-temperature superconductors (based on YBa2Cu3O7) generally operate at a transition temperature around ~100 K (-173°C). If you consider room temperature to be 295 K (22°C), you can see that at present superconductors are far from the room temperature operating regime.”
And finally, at least one of our experts has a sense of humour:
“I have nothing to add except the temptation to say that these superconductors were used by Elvis Presley to kill President Kennedy!”
END
Perhaps I'll need a few more of those links you have. Or how about just a cut-and-pasted article for all of us to read about this significant breakthrough in technology.
PS - I am aware of the new diamond/oxygen process which is currently not fully proven, but being looked at.
Don't get me wrong. I'm all for improvements and new technology. But claiming room temp superconductors for cables needs to be verified, for me to accept these claims. I'm even willing to accept near-room temp superconductors, or room-temp near-superconductors. Show us something.
