"A resercher... has invented a method of making high-temperature superconducting (HTS) cables that are thinner and more flexible than demonstration HTS cables now installed in the electric power grid while carrying the same or more current"
"They are roughly one-tenth the diameter of typical [demonstration] HTS cables used in the power grid."
"mass production is feasible"
http://www.physorg.com/news/2011-02-com ... -nist.html
New Compact High Temperature Superconductor Cable
-
TecnoImpacto
- Posts: 15
- Joined: Sun Aug 08, 2010 4:32 pm
- Location: Spain
- Contact:
http://en.wikipedia.org/wiki/High-tempe ... nductivityHigh-temperature superconductors (abbreviated high-Tc or HTS) are materials that have a superconducting transition temperature (Tc) above 30 K (−243.2 °C)
It may be time to change the definition but for the moment, the title is correct.
Aero
Your statement can be absolutely proven true merely by saying that YOU don't accept it, but...Giorgio wrote: We all know that there is really no universally accepted definition for "High Temperature Superconductivity".
Seems like a good enough definition to me.Wikipedia wrote:High-temperature superconductors (abbreviated high-Tc or HTS) are materials that have a superconducting transition temperature (Tc) above 30 K (−243.2 °C). From 1960 to 1980, 30 K was thought to be the highest theoretically possible Tc. The first high-Tc superconductor[1] was discovered in 1986 by IBM Researchers Karl Müller and Johannes Bednorz, for which they were awarded the Nobel Prize in Physics in 1987.
Just because is mainstream and someone wrote it into wikipedia it does not mean that it is an universally accepted definition or that it is true.
The reason why they started to call them "High Temperature" is explained in the same lines you quote, and that reason is an absolute nonsense from a physics point of view.
Also, at the best of my knowledge, is not like 30K was ever defined by anyone (or in any literature) as the transition temperature between Low and High temperature superconductors.
High temperature Superconductors should be defined as a Superconductor working from ambient temperature to higher ones. We can digress about what this temperature could be, but at least this is something that normal people can easily understand and that makes sense from a physics point of view.
The reason why they started to call them "High Temperature" is explained in the same lines you quote, and that reason is an absolute nonsense from a physics point of view.
Also, at the best of my knowledge, is not like 30K was ever defined by anyone (or in any literature) as the transition temperature between Low and High temperature superconductors.
High temperature Superconductors should be defined as a Superconductor working from ambient temperature to higher ones. We can digress about what this temperature could be, but at least this is something that normal people can easily understand and that makes sense from a physics point of view.
As a long time lurker, Giorgio, I appreciate your posts.
Regarding the terminology, "high temperature superconductor", however, this is the common usage of the word for virtually everyone involved in the field. Actually ever since the first discovery of materials that superconduct above 77 K, this temperature (77 K) has become something of a defacto threshold for the term, given the obvious economic benefit of cooling to this temperature cheaply with liquid nitrogen. (No one gets very excited about "high" temperature superconductors in the 30K to 65K range anymore, because of the economics).
"Room Temperature superconductivity" is the new holy grail in superconductivity. And who knows, maybe Prins is right, and he's already demonstrated it.
I'm not holding my breath...
Regarding the terminology, "high temperature superconductor", however, this is the common usage of the word for virtually everyone involved in the field. Actually ever since the first discovery of materials that superconduct above 77 K, this temperature (77 K) has become something of a defacto threshold for the term, given the obvious economic benefit of cooling to this temperature cheaply with liquid nitrogen. (No one gets very excited about "high" temperature superconductors in the 30K to 65K range anymore, because of the economics).
"Room Temperature superconductivity" is the new holy grail in superconductivity. And who knows, maybe Prins is right, and he's already demonstrated it.
I'm not holding my breath...
Well, gosh! Room temperature superconductors already fill that niche. What are you gonna do, re-define physics terminology to make sense? If that's your goal, start with medicine, not physics.Giorgio wrote:High temperature Superconductors should be defined as a Superconductor working from ambient temperature to higher ones. We can digress about what this temperature could be, but at least this is something that normal people can easily understand and that makes sense from a physics point of view.
Aero
High Tc is >= 77k
Georgio - liquid nitrogen is very, very cheap compared to other forms of cryogenics. Anything above 77k is considered high Tc by the engineering and physics world due to it's low cost and simplicity.
In this case, it is the reality of physics and engineering that gives us the current definition of high Tc. Superconductivity at ambient has already been labeled http://en.wikipedia.org/wiki/Room-tempe ... rconductor
In this case, it is the reality of physics and engineering that gives us the current definition of high Tc. Superconductivity at ambient has already been labeled http://en.wikipedia.org/wiki/Room-tempe ... rconductor
(snip)Giorgio wrote:Just because is mainstream and someone wrote it into wikipedia it does not mean that it is an universally accepted definition or that it is true...
Well, in reality you need to cool the SC well below its Curie temp. In many if not most SC applications you still use liquid helium. The lower the temp, the better the capabilities. Same goes with pressure. You want the pressure as high as you can safely get.
What is the difference between ignorance and apathy? I don't know and I don't care.
The first "high temperature superconductor" was well BELOW 77K.
As for superconductors in the 30 K range, MgB2 is a new favorite.In the early 1980s, Müller began searching for substances that would become superconductive at higher temperatures. The highest critical temperature (Tc) attainable at that time was about 23 K. In 1983 Müller recruited J. Georg Bednorz to IBM, to help systematically test various oxides. A few recent studies had indicated these materials might superconduct. In 1986 the two succeeded in achieving superconductivity in lanthanum barium copper oxide (LBCO) at a temperature of 35 K. Over the previous 75 years the critical temperature had risen from 11 K in 1911 to 23 K in 1973 where it had remained for 13 years. Thus 35 K was incredibly high by the prevailing standards of superconductivity research. This discovery stimulated a great deal of additional research in high-temperature superconductivity, leading to the discovery of compounds such as BSCCO (Tc = 107 K) and YBCO (T'c = 92 K).
Magnesium diboride (MgB2) is a simple ionic binary compound that has proven to be an inexpensive and useful superconducting material.
Its superconductivity was announced in the journal Nature in March 2001.[1] Its critical temperature (Tc) of 39 K (−234 °C; −389 °F) is the highest amongst conventional superconductors. This material was first synthesized and its structure confirmed in 1953,[2] but its superconducting properties were not discovered until 2001. The discovery caused great excitement.
Ah well, according your point than any future higher temperature superconductor will fill that niche.Aero wrote:Well, gosh! Room temperature superconductors already fill that niche. What are you gonna do, re-define physics terminology to make sense? If that's your goal, start with medicine, not physics.Giorgio wrote:High temperature Superconductors should be defined as a Superconductor working from ambient temperature to higher ones. We can digress about what this temperature could be, but at least this is something that normal people can easily understand and that makes sense from a physics point of view.
Back when I was younger we used to have international commitees to fix common definitions among engineers and it does not occur to me that this has been done yet for Superconductor terminology. But I guess that now that we have wikipedia these type of details should not bother us anymore.
You are perfectly right.sdg wrote:"Room Temperature superconductivity" is the new holy grail in superconductivity.
My point was simply that people like us who are a little more into this field should start to use better definitions to avoid confusion. I do not count anymore the time I had to explain to people that high temperature superconductors have nothing to do with "high temperatures" and that end user applications are still far away.
For us is silly and just a terminology issue, for the normal guy is something not so easy to grasp and that makes science more alienating than what already is.
Anyhow, maybe I am just overreacting.