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Post by Pttg on Nov 5, 2016 22:52:47 GMT
The existing crop of high-temperature superconductors function up to around 130-140K. Maybe a little low to use as thermocouples in our reactors, but still a possible substance for launcher forcers and coilgun coils, and as we've seen with the borosillicate glass bug, high conductivity can do amazing things. A ship such as a carrier or a missile frigate that doesn't mind the fact that its radiators are gargantuan could reasonably make use of such devices.
The addition of heat pumps would make this sort of thing a LOT more effective....
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Post by n2maniac on Nov 12, 2016 8:27:48 GMT
Critical magnetic field strength is the limiting factor here. Everything gets difficult above 10T, and the strongest manmade magnetic fields generally end up relying on heavily cooled copper. That being said, this field strength is still far above the saturation field of the magnetics used in coilguns is far lower, so it may make good ammo (just needs to be pre-cooled).
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Post by argonbalt on Nov 12, 2016 18:36:48 GMT
Critical magnetic field strength is the limiting factor here. Everything gets difficult above 10T, and the strongest manmade magnetic fields generally end up relying on heavily cooled copper. That being said, this field strength is still far above the saturation field of the magnetics used in coilguns is far lower, so it may make good ammo (just needs to be pre-cooled). NOW THERE IS AN EXCELLENT IDEA! All this time we were thinking that the guns themselves had to be bigger and stronger with more high wattage capacitors, but what if the issue could be mitigated through the AMMUNITION! Pre cooled ferromagnetic iron rounds! that is a very attractive idea. |
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Post by n2maniac on Nov 12, 2016 21:23:58 GMT
Critical magnetic field strength is the limiting factor here. Everything gets difficult above 10T, and the strongest manmade magnetic fields generally end up relying on heavily cooled copper. That being said, this field strength is still far above the saturation field of the magnetics used in coilguns is far lower, so it may make good ammo (just needs to be pre-cooled). NOW THERE IS AN EXCELLENT IDEA! All this time we were thinking that the guns themselves had to be bigger and stronger with more high wattage capacitors, but what if the issue could be mitigated through the AMMUNITION! Pre cooled ferromagnetic iron rounds! that is a very attractive idea. Forget ferromagnetic, just have a superconducting disc that is a perfect diamagnet. The coilgun magnetic flux acts as pressure behind such a disk, accelerating it. Also, I'll worry about increasing coilgun efficiency when my coilguns start creeping down to 100% efficiency. Currently 10,000% is not unheard-of, and a physics bug lurks somewhere beneath my multi-GW kinetic projectile beams. |
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Post by ash19256 on Nov 17, 2016 20:16:59 GMT
On the subject of superconductors, I've actually heard of a kind of interesting idea for superconducting cables over on Spacebattles, and figured this forum might be a good place to look for a reality check on it. I'm not really all that hopeful about it standing up to scientific scrutiny, but it at least sounds plausible to someone who doesn't know much about how superconductors work. Basically, the idea was that you would contain a substance that becomes a superconductor when cooled (the original poster of the idea specified hydrogen sulfide) inside of a graphene matrix that was specially created to serves an electrically driven cooling system (ie. when electricity is flowing through it, it uses some of it to cool the interior of the cable), which rapidly cools down the substance within until it becomes a superconductor (temperature specified by the original poster of the idea was 203 Kelvin, although I think they may have forgotten a minus symbol), at which point power switches from flowing purely through the graphene matrix to flowing through both the graphene matrix and the substance inside of it. It technically isn't a superconductor, but it becomes one when power is run through it.
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Post by apophys on Nov 18, 2016 18:13:01 GMT
Cooling the interior of the sandwich would be basically a thermocouple in reverse - totally doable, just remember that the external surface of such a layered material would be hot.
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Post by ash19256 on Nov 19, 2016 5:09:59 GMT
What kind of temperatures would we be talking about? Would it be something that would need dedicated cooling to keep it from melting concrete and such? Or would it be practical for use in large scale power grids without any sort of dedicated cooling, ie. replacing the cables on top of the long-distance power poles you see along the highways occasionally?
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Post by n2maniac on Nov 22, 2016 3:36:43 GMT
On the subject of superconductors, I've actually heard of a kind of interesting idea for superconducting cables over on Spacebattles, and figured this forum might be a good place to look for a reality check on it. I'm not really all that hopeful about it standing up to scientific scrutiny, but it at least sounds plausible to someone who doesn't know much about how superconductors work. Basically, the idea was that you would contain a substance that becomes a superconductor when cooled (the original poster of the idea specified hydrogen sulfide) inside of a graphene matrix that was specially created to serves an electrically driven cooling system (ie. when electricity is flowing through it, it uses some of it to cool the interior of the cable), which rapidly cools down the substance within until it becomes a superconductor (temperature specified by the original poster of the idea was 203 Kelvin, although I think they may have forgotten a minus symbol), at which point power switches from flowing purely through the graphene matrix to flowing through both the graphene matrix and the substance inside of it. It technically isn't a superconductor, but it becomes one when power is run through it. Not 100% sure how power is extracted. If it uses an outer conductor as well for the current return path for cooling as a thermocouple (probably a few in series), then maybe. If it is 2 interior conductors, then there is a way to get this to work but it won't be simple (eg. think attaching heat pumps periodically to the wire to cool refrigerant running along the wire)). The paper from a year ago or so on hydrogen sulfide is really intriguing, and could possibly be the highest temperature practical "superconductor" in existence (yes, it needs a very high pressure tube to compress it, but it beats the other options at the moment). 203K sounds about what I remember, which was above dry ice temperatures. Be a great thing to try to build IRL if it wasn't such high pressure of a stinky, toxic substance. |
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