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Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity
- graycat 10y agoUse for a skyhook? A skyhook is what? Dirt cheap way to mass into earth orbit. How? Put a weight on a string, attach the string at, maybe, the equator of earth, put the weight into orbit, and let the centrifugal force of the weight keep it in orbit and keep the string tight. Then to put mass into orbit, let it crawl up the string from electric power conducted from earth in the string. Main problem: Getting a sufficiently strong string!
- shrewduser 10y agoI doubt this would be anywhere near strong enough for a space elevator. And i think a sky hook is something else
- andrewguenther 10y agoThere are a lot of science fiction uses of "skyhook" this is one is them.
- azernik 10y agoA skyhook is generally a space elevator that doesn't go all the way to the ground, and so doesn't have to be quite as precise about orbital velocity and the like.
- jimnotgym 10y agoI thought a skyhook was one of those things you send the apprentice kid to the stores for, like tartan pain, spirit level bubbles, long stands and a weight with no point? Maybe even a left handed screwdriver...
- Fjolsvith 10y agoAt scout camp we'd send the new kids down to the waterfront for 50 feet of shoreline.
- jon_richards 10y agoPretty sure it's the thing in batman that allows troops to reverse skydive.
- hwillis 10y agoYou mean that thing by the CIA which was successfully tested in 1958, and later was a plot device in a Batman movie: https://en.wikipedia.org/wiki/Fulton_surface-to-air_recovery_system https://en.wikipedia.org/wiki/Fulton_surface-to-air_recovery...
- douche 10y agoAlso on display much earlier in Thunderball and The Green Berets.
- ieatkittens 10y agoWifi cable
- deleted 10y ago[deleted]
- bbcbasic 10y agoWhat if a plane gets tangled up in it?
- hwillis 10y agoProposals were made around 1000 km altitude at the lower tip. Boeing proposed a 600km tether with a transfer altitude of 100km (at mach 10), and later increased that to 150 km. The Lockheed U-2 is one of the highest flying airplanes ever, our main cold war spy plane. It flew twice as high as a passenger jet, and cruised at 70,000 feet, just over 21 km. Planes would not get tangled in it.
- bbcbasic 10y agoThanks. The GP's comment "attach the string at, maybe, the equator of earth" is what confused me, thinking the string is attached to the earth, with the weight in orbit.
- hwillis 10y agoMain problem is more that there is no advantage to a skyhook if you're just putting things into orbit. Every kilo you lift with a skyhook pulls it down and it has to be used to de-orbit that mass, or lifted up by rockets or thrusters etc. Unlike an actual space elevator, or orbital ring, or launch loop, it doesn't hold itself at altitude. Also, there's really no need for the tether to be conducting. For one, you could just use carbon fiber, or have a single conductor mixed in with tensile fibers, or just use a solar panel, or just spin the whole thing (which gives you the real advantage of bringing you up to orbital velocity)
- Fjolsvith 10y agoIf there was a big counterweight out at the far end of the cable, and it was sufficiently long enough, wouldn't the centrifugal force acting on the weight counteract the kilos lifted?
- hwillis 10y agoNo, that doesn't work for anything less than a space elevator or the other devices I mentioned. A space elevator is tied down to the earth, and constantly trying to fly off into space. A skyhook is basically nothing more than a LEO satellite with a very, very long rope hanging off it. If you pull on the rope, you pull the satellite down since there is no centrifugal force besides the inertia keeping it in orbit. If you make a very heavy counterweight, it just delays the inevitable pulling down, and its that much harder to get into orbit. There's no point.
- WJW 10y agoWhile the energy imparted to the object being leunched is the same, you would be able to use high-ISP thrusters like ion engines to boost the counterweight back up. They can't be used lower down though, due to not having enough thrust for use in the atmosphere. This would have the advantage of raising the average ISP during the launch, thus having to use less propellant overall. It might even be possible to use tether-based propulsion for the counterweight, which wouldn't need any propellant at all but push against the Earths' magnetic field.
- has2k1 10y agoI have encountered the term in another context. > A "skyhook" is an imaginary device for hanging an object from the sky. The word originated in a sarcastic remark by a frustrated pilot of a reconnaissance plane in the First World War, when told to stay in the same place for an hour: "This machine is not fitted with skyhooks," he replied. From, "The Evolution of Everything: How New Ideas Emerge" by Matt Ridley
- leke 10y agoSo ummm, what kind of nutrition does graphine have?
- jansenv 10y agolots of carb-ons and fiber.
- mgiannopoulos 10y agoThis calls for an evolved Spider-Man storyline :)
- conqrr 10y agoAnd a Carbon-Spidey(Silky??) vs Electro sequel.
- sgt101 10y agoDid you know that rubber conducts electricity ? Ok it's conductivity is 10^-14 s-m, but if faced with a kragagooogle volt of potential, it will conduct. Carbon fibre conducts rather better... which can be a worry if you are in a sail boat in a thunderstorm.. but to be a useful conductor we are looking for 10^6 s-m or better, better than, or close to copper. What does this stuff do? The article does not relate.
- notliketherest 10y agoWhat is a kragagooogle ?
- vlgs 10y ago|<----- its this much ----->|
- deleted 10y ago[deleted]
- flukus 10y agoThe only google results come back here, so I'm guessing it's a place holder word for "a lot", like a bajillion.
- inopinatus 10y ago"kraga" appears to be a swedish word meaning "flange", so hopefully that clears things up.
- Groxx 10y agoGoogle guesses Icelandic for me, which apparently translates as "collar". Seems obvious in retrospect.
- paulmd 10y agoAlso, there are various forms of conductive rubber available. Typically this is done by mixing carbon powder into the rubber. https://en.wikipedia.org/wiki/Conductive_elastomer https://en.wikipedia.org/wiki/Conductive_elastomer
- dnautics 10y agoNo evidence that the silk contains graphene, low n. Visually inspect the em cross section... Can you see a difference? The authors don't produce a quantitative measure of entropy in the pictures to justify the claim that they are different.
- imaginenore 10y agoPrevious posts: https://news.ycombinator.com/item?id=12664699 https://news.ycombinator.com/item?id=12664699 https://news.ycombinator.com/item?id=12674063 https://news.ycombinator.com/item?id=12674063 https://news.ycombinator.com/item?id=12683994 https://news.ycombinator.com/item?id=12683994
- krige 10y agoIs graphene even a thing? Last I checked it was still a magical hypothetical substance made with pencil shavings and duct tape (that's an exaggeration but only a mild one). Every now and then I see news about graphene being the next big thing, like, very soon, but the results I see fail to prove that it's even an actual substance, and the evidence is the lab that made it swearing that it's totally a thing.
- george_ciobanu 10y agoPlot twist: Silk worms leave study disgusted with shity new taste of food.
- mrfregg 10y ago"...by spraying fresh mulberry leaves with SWNTs or GR solutions...containing SWNTs with solution concentration of 0.2 and 1.0 wt % and GR at the concentration of 0.2 and 2.0 wt %" I'd be surprised if they tasted anything at all, if they can taste :)
- wastedhours 10y agoInteresting that they're not dangerous - had a pot of SWNTs and the warning labels against breathing them in were 4x larger than the container itself! Same with getting them on your hands, thought it was due to them creating lots of micro-cuts - guess the low concentration makes that less likely?
- Already__Taken 10y agoNanoscale things are considered dangerous because they happily pass straight through cells. Not something you want to find out is a problem. /notascientist
- mirimir 10y ago> Zhang’s team tested conductivity and structure after heating the silk fibers at 1,050°C (1,922°F) to carbonize the silk protein, and unlike untreated silk, the carbon-enhanced silk conducted electricity. After that much heat, would this silk be useful for making fabric?