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Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

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Re: Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

#41

Post by flashingleds »

sgt101 wrote: post #8

Did 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.

This summary doesn't give numbers, but the journal article being discussed does. About 3e3 to 1e4 S/m for different preparations, compared with zero for untreated silk. Performed as a two-probe DC measurement, so once you factor in contact resistance it might be even better. The details are scarce, so you'd probably want to see it repeated more carefully before concluding anything.

Re: Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

#42

Post by graycat »

hwillis wrote: post #32
graycat wrote: post #30

Earlier quoted context omitted.

I was being very simple. I used skyhook as informal and humorous and did not know that it had a technical meaning in this context. I was thinking more of what is commonly called a space elevator but did not look up the details, e.g., synchronous orbit or some such. Really I was just commenting on the spider silk with carbon fibers that might add some of the needed strength and also permit sending power to whatever wa…

Oh, I figured you meant it. In that case carbon fiber is stronger, more conductive, and cheaper. Why bring up space elevators if you have no interest in saying or learning something about them?

> Why bring up space elevators if you have no interest in saying or learning something about them?

Because when I looked into space elevators, the main problem was getting the cable strong enough for its weight. So, with spider silk, already amazingly strong, with carbon, a first guess, or hope, for an application would be for a space elevator.

So, in response to the OP, I mentioned the cable, string, whatever, for skyhooks, space elevators, or whatever.

Again, my understanding is that space elevators are well enough understood and the main issue is just the cable. So, given the OP, I mentioned the cable, mostly just the cable, without digging into the well understood details of space elevators. I wasn't trying to discuss space elevators in general, just the cable and just in response to the OP.

Re: Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

#43

Post by Groxx »

inopinatus wrote: post #29
notliketherest wrote: post #21

Earlier quoted context omitted.

What is a kragagooogle ?

"kraga" appears to be a swedish word meaning "flange", so hopefully that clears things up.

Google guesses Icelandic for me, which apparently translates as "collar".

Seems obvious in retrospect.

Re: Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

#44

Post by bbcbasic »

hwillis wrote: post #20
bbcbasic wrote: post #13

Earlier quoted context omitted.

What if a plane gets tangled up in it?

Proposals 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.

Thanks. 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.

Re: Graphene-Fed Silkworms Produce a Super-Strong Silk That Conducts Electricity

#45

Post by vorotato »

hwillis wrote: post #28
Fjolsvith wrote: post #25

Earlier quoted context omitted.

If 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?

No, 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 y…

Landing on the moon also pulls it down, also landing on existing satellites. There is no special nature of ropes that "pulls down". Secondly there's no reason why we couldn't take a space object and use it as the very heavy counterweight.
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