Slashdot Mirror
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."
Are still high.... Give it a few years and it may be cheaper.
-- (this is a sig) My Computer Programming Forumhttp://www.programers.co.nr/
The only magic missing from that project is money.
To offset political mods, replace Flamebait with Insightful.
Sorry, but that's the first thing I think of when a new super material is described.
I can't think of any other technology that, barring a really huge breakthrough (like anti-gravity) would truly make space travel a practical reality for millions. Even Arthur C. Clarke in his "Fountains of Paradise" book alluded to this saying that the supposedly hyper-efficient rockets of the future would create so much environmental damage (pollution, sonic booms) that really heavy traffic couldn't be sustained.
Maybe if we had cold fusion (or something like it like muon catalyzed fusion or zero-point energy) space travel on a large scale would be practical but these "breakthroughs" might be just as far (or impossibly far!) away.
By the way, did anyone see the developments (at MIT?) where they showed a nano structured "tape" able to support the weight of a full grown man with only a few inches of surface area? And it was able to be re-used thousands of times before using its grip? Perhaps the space elevator could be made of material structured this way, I mean if that thing is ever going to be built it will essentially be a gigantic 23,000 mile long SINGLE MOLECULE anyway so nano structuring should be almost trivial!
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.
To me, this suggests a couple more interesting applications:
Battery electrode
Supercapacitor dielectric
Chemical sensor
Nanofiltration
Lightweight structural blocks/foams (this is essentially a spun aerogel with a water solvent...)
Carbon wire (copper is expensive)
I am sure there are others.
No, it's a graphene fiber, not an ass-fiber. Didn't you even read the summary?
You're thinking of carbon nanotubes, not graphene. Graphene is a layer of carbon only a few atoms thick, which (like carbon nanotubes) is electrically conductive, and (unlike carbon nanotubes) is also transparent. So if they can iron out the manufacturing issues, they can create transparent panels (like glass) that are electrically conduct. This has all kinds of useful applications for display panels (transparent ipads, anyone?), windows that function as TVs, monitors, solar energy collectors, etc.
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
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.
Carbon fiber, carbon nanotubes and graphene fiber are all different forms with different properties.
My ass-fibers are graphene, you insensitive clod!
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
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.
... and a material of the necessary tensile strength. If we had that, then the money probably wouldn't be that hard to get.
But as someone else replied, apparently this ain't it. Or at least, not yet. A pity, really. I was hoping the same thing.
Just because it works, doesn't mean it isn't broken.
That's an overhand knot, not a square knot. If you want to join two like-sized ropes use the square knot; neither the overhand nor the figure-8 can do that.
You're right that the figure-8 is better than the overhand in most ways.
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.
Edit: damn you slashodot for no edit feature. The research was at both South Korea and Singapore, so china is almost but not quite correct.
my first thought was how soon will graphene yarn become available?
Relevant xkcd: http://www.xkcd.com/37/
I was thinking more like this:
Say you send a 100 ton payload up the tether. After a certain point on the ascent, you stop trolling up the fiber, and actually have to start applying breaks on it, because the centrifugal force (please, I know the difference between it and centrepital force. The former is a pseudo force, yes, but still real.) Acting on the carriage will be correlated with the inertial mass of the carriage, the rate of rotation, and the radal distance from the center of rotation, in relation to the gravitational force. At some point centrifugal forces will overcome gravity, and this will pull the tether very tight.
The problem is not with lifting the island, but with tearing the anchor of the tether out of the ground.
Your head unfortunately doesn't have a good handle on space elevators.
A space elevator doesn't HAVE to be right at the equator, although that's the easiest way. The equator doesn't go through central America.
Islands are perfectly fine. A space elevator doesn't pull on the ground station much. If it did, your ground station would certainly fail before "strong continental plate foundations" were an asset. Actually, an artificial, mobile sea platform may be a good idea because you can move it around to tow the tether a bit if you need it to dodge some space junk.
Space elevators don't go to low earth orbit. They MUST go somewhat past geosynchronous orbit. Geosynch is actually the MIDDLE of the tether unless you weight the space end of it, say by attaching it to an asteroid.
Have you ever seen a bird sitting on a power line? Not that it really matters anyway, you can get some high voltages from voltage differentials in the atmosphere (friction with the wind is probably a negligible contribution) but not much current. If somehow you did manage to get a decent amount of current, you'd use it as a power plant.
The olympics are contentious because there is only one. And even so, we manage to find a place to put them every two years, don't we? A space elevator would probably be built by a group of countries, like CERN or some of the other large projects. Fights over the location would probably be considerably simplified because no large industrial nation would be a suitable host. Instead it would probably end up somewhere like French Guiana where the European Space Agency already has their launch facilities, BTW.
If the tether were to break, most of the lower end would probably burn up in the atmosphere. The rest would land fairly softly. The thing is LIGHT remember.
Given an appropriate material, a space elevator will get built. Various plans put it well within the reach of private enterprise if no governments get around to doing it.
I don't think you understand the amount of force that would be required to do that. Maybe if the tether got hit by an asteroid the size of Dallas. Nevermind that in the event of such a catastrophe, they could simply cut the cable at the base, and the whole thing goes flying out into space. There would be plenty of time, as it would easily take weeks to fall.
Also, you demonstrate your lack of understanding of the space elevator concept by claiming the fiber needs to extend to low earth orbit. It doesn't. It has to go to GEOSTATIONARY orbit. If you don't know the difference, Geostationary is MUCH further away, and that is the MINIMUM distance. In reality, it needs to extend beyond it to keep the tether taught.
I expect the effect of graphene on the human body to be similar to asbestos. So expect increased cancer rates, Asbestosis, and other health problems from people who work with it as a raw material.
“Common sense is not so common.” — Voltaire
Can you please explain to me what the hell a butt hurt-troll is?
Graphene oxide and graphene are two different materials. As different as iron and rust, particularly in electrical properties.
This deliberate misleading of people outside the field by nanotechnology researchers is a major problem and has been for several years.
Three times? No. By pure coincidence, geostationary orbit is just under one circumference, 89% of one to be exact. In a worst case scenario, that 22kmi comes crashing down, and doesn't quite wrap around the world once, while the counterweight gets flung out into space. You could actually cut the cable somewhere around 15kmi, and the remainder would be going fast enough to remain in orbit. Send some robot to spool it up to reduce the navigation hazard, and then collect it later. By necessity, such a thing would be placed on the equator, so between South America (Equador, Columbia, Northern Brazil), Sub-Saharan Africa, and Indonesia, pick two out of three to hit. You could place scuttling charges on that section of cable every couple miles, such that the cable harmlessly falls down much as long party streamers. The worst damage it would cause would be shorting out any electrical lines it managed to cross.
A steel pipe also has properties that a steel pipe doesn't, but they're still the same material.
You just blew my ... parser.
I feel fantastic, and I'm still alive.
RTFA. Graphene oxide is an intermediate stage. From the article: " A final chemical reduction treatment turns the long strings of graphene oxide back into graphene."
So the final product is definitely graphene.
That's only true if you think Canada and Mexico are 'almost' the USA.