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Graphene Spun Into Meter-Long Fibers
ananyo writes "Nano-sized flakes of graphene oxide can be spun into graphene fibers several meters long, researchers in China have shown. The strong, flexible fibers, which can be tied in knots or woven into conductive mats, could be the key to deploying graphene in real-world devices such as flexible batteries."
not yet. I RTFA.
There are mechanical defects in the graphene strand that make it weaker than traditional carbon fiber.
They are going to need to be able to generate nearly perfect strands before that becomes an option.
Whenever I see "space elevator!" Mentioned, this course of action plays out in my head:
A space elevator/orbital tether needs to be at the rotational equator. This means central or south america, or africa. (Islands would lack the strong continental plate foundations to hold the tether to the earth.)
The tether itself will be many kilometers long. It has to extend all the way, vertically, into low earth orbit.
The tether, if made of a conductive material like graphene, would become super charged with high voltages just from the air currents whorling around it. (Don't believe me, run a kite on copper wire and attach a volt meter between it and the ground. Remember that the kite string is orders of magnitude shorter than an orbital tether.) In addition to this constant charging, you have the high energy disturbances of the ionosphere to deal with. I suppose this could make the tether into a fantastic dc powerplant, but it would also make putting a carriage on the tether much more difficult.
Then you have the political problems.... look at the shit that happens with selecting where to hold the olypic games. Imagine the politics involved in breaking soil on an orbital tether.
And then, finally, what happens if there is an accident? Many kilometers of highly energized, and kinetically taught razorwire with toughness surpassing all other construction materials whipping round the planet sounds pretty dangerous to me.
Really, the logistics of such a project just don't make for a plausible project, barring some kind of officious one world government that doesn't brook dissent.
And then, finally, what happens if there is an accident? Many kilometers of highly energized, and kinetically taught razorwire with toughness surpassing all other construction materials whipping round the planet sounds pretty dangerous to me.
I don't have the link handy, but someone actually did the math on this. Due to the mass vs. surface area (and how much energy will be lost to air resistance), the cord will land softly along the surface of the earth from the anchor to the breakpoint. The greater danger will be had by the station at the top of the cord, but there are ways to stabilize the rotation it would suffer.
If we only had to go to LEO, we'd probably have done it already.
Also, there are a ton of satellites in LEO, and most of them are likely to hit the tether at some point. It is just a matter of time (and not as much time as you'd think -- you'd probably have a near miss every couple weeks).
I RTFA. It actually mentions that the Korea Advanced Institute of Science and Technology where this was done is actually in, who would have guessed it, South Korea! and not China.
Wait, I just told you the guys writing about graphene oxide are misleading you, and your response is that I should read their article? Think about that for a minute.
I am a graphene researcher. I've published my own papers on these materials. I've done my own measurements. The resistance, carrier mobility, noise power and chemical reactivity of reduced graphene oxide is not the same as graphene. That's what their data says too, the press release text from Nature doesn't matter.