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The World's Longest Carbon Nanotube

Zonk posted more than 7 years ago | from the woot-nanohair-different-color-every-week dept.

142

Roland Piquepaille writes "As you probably know, carbon nanotubes have very interesting mechanical, electrical and optical properties. The problem, currently, is that they're too small (relatively speaking) to be of much use. Now, researchers at the University of Cincinnati (UC) have developed a process to build extremely long aligned carbon nanotube arrays. They've been able to produce 18-mm-long carbon nanotubes which might be spun into nanofibers. Such electrically conductive fibers could one day replace copper wires. The researchers say their nanofibers could be used for applications such as nanomedicine, aerospace and electronics."

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Wow (5, Funny)

jswigart (1004637) | more than 7 years ago | (#18915257)

So perhaps the internet will indeed become a series of tubes?

Re:Wow (4, Funny)

Jeff DeMaagd (2015) | more than 7 years ago | (#18915289)

Maybe. Maybe in an odd twist, the Internet might actually become a large fleet of nano-trucks.

Re:Wow (4, Funny)

ScrewMaster (602015) | more than 7 years ago | (#18915295)

That's a scary thought ... Ted Stevens actually being prophetic, rather than just wrong.

Re:Wow (4, Interesting)

Reality Master 101 (179095) | more than 7 years ago | (#18915795)

Ted Stevens actually being prophetic, rather than just wrong.

You know, Stevens gets a totally bad rap on that whole thing. Exactly what is wrong with that analogy? Even UNIX uses the analogy with pipes; Ritchie* could have just easily called them tubes rather than pipes. And yes, the "tubes" of the Internet CAN get clogged up if there's too much flowing through them.

I've never understood why he took such a beating about it. I guess some people are just determined to believe the worst about people, as though the guy though the Internet was literally air-filled tubes.

Re:Wow (4, Informative)

espressojim (224775) | more than 7 years ago | (#18915963)

Maybe this is why? Even if the metaphor isn't horrible, the delivery was:

Ten movies streaming across that, that Internet, and what happens to your own personal Internet? I just the other day got... an Internet was sent by my staff at 10 o'clock in the morning on Friday, I got it yesterday. Why? Because it got tangled up with all these things going on the Internet commercially.

[...] They want to deliver vast amounts of information over the Internet. And again, the Internet is not something you just dump something on. It's not a big truck. It's a series of tubes. And if you don't understand those tubes can be filled and if they are filled, when you put your message in, it gets in line and it's going to be delayed by anyone that puts into that tube enormous amounts of material, enormous amounts of material.


From wikipedia.

Re:Wow (3, Insightful)

Anonymous Coward | more than 7 years ago | (#18916063)

Exactly what is wrong with that analogy?

The context it was said in, he did not say "The Internet is a worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP) [Wikipedia]... You can think of it as a series of tubes...".

Here's a clip [youtube.com] with interesting parts from his speech.

I'm also sure you can find the whole thing in the related clips pane. Listen to it (again?) and judge for yourself if he knows what he's talking about

I've never understood why he took such a beating about it

I believe the beating was NOT because he doesn't understand "what the internet is" (that's not a crime, last time I checked), but the fact that he's a legislator working on something that he does not understand at all.

And of course this generation likes bashing on older people because they don't know that the next generation will mock them just the same...

Re:Wow (2, Interesting)

ResidntGeek (772730) | more than 7 years ago | (#18916153)

When the tubes of the internet get clogged, it's not because of the tubes, it's because of the machines at the end. When tubes are clogged due to too much toilet paper passing through, you have to dig up the tubes and replace them. When a fiber-optic cable is clogged due to too many movies, you put faster routers at the ends - not at all like digging up a cable network all over the world. That's the problem with the analogy, it broke down *exactly* at the place he invented it for.

Re:Wow (1)

iminplaya (723125) | more than 7 years ago | (#18916405)

Ritchie* could have just easily called them tubes rather than pipes.

Whatever happened to just calling them wires? I mean, like, DUUUH!

Re:Wow (1)

compro01 (777531) | more than 7 years ago | (#18916769)

Whatever happened to just calling them wires?

that died when the wires became optical fibres.

Re:Wow (2, Interesting)

Burpmaster (598437) | more than 7 years ago | (#18917205)

The analogy isn't too terrible. It conveys the notion that Internet bandwidth is a shared resource. However, Ted Stevens demonstrated very clearly that he has no idea what he's talking about. He seems to think that when somebody downloads a movie, the entire movie gets put into the 'tube' and all other data gets in line behind it. He thinks an e-mail he got several days after it was sent arrived late because too many movies were coming through the tubes. Not only that, but he referred to the e-mail as "an internet."

He doesn't realize that data is divided into packets, where a limited amount are in transit at one time for each transfer. This fact is very important. It means that bandwidth is shared roughly evenly between all the users of a 'tube' at any given moment, and that e-mails can always be delivered just a quickly as a few packets of a movie would be delivered. His e-mail could only have been delayed by a messed up mailserver, but he didn't know enough about the Internet to realize that.

Re:Wow (2, Interesting)

7Prime (871679) | more than 7 years ago | (#18917461)

I'm from Alaska. I fucking hate Ted Stevens, I think he's a jerk, and I disagree with about 95% of his politics. But an idiot he is most definitely not. He knew exactly what he was talking about... which actually worries me a lot more than if he didn't. He was attempting to explain it in layman's terms to a bunch of people, who, honestly, were a lot stupider than him. He has a tendancy to over-dumb-down statements like this.

I think its kinda dangerous to assume that he's stupid, because you fail to realize just how much of a cold, calculating demon he is. Believe me, I know people who used to be former interns of his... they're all hoping he'll die soon, but from what I've heard, his physical health is like that of a 30-year old.

Oh well, as long as his party doesn't get control back, we should be relatively safe.

My microtube is bigger than your nanotube (3, Funny)

mrbluze (1034940) | more than 7 years ago | (#18915591)

... do you think they could be compensating for something?

One nanotube: two birds (4, Funny)

ian_mackereth (889101) | more than 7 years ago | (#18915301)

So, not only will we get light, cheap, immensely strong conductors, we'll also have a good market-driven reason to get all that valuable carbon out of the atmosphere!

Voila! No more global warming!

8-)}

Re:One nanotube: two birds (1)

Dr. Eggman (932300) | more than 7 years ago | (#18915435)

But then we'll go too far, we'll continue to make longer and longer nanotubes, until one day we will make a nanotube so long it will destroy us all!

Re:One nanotube: two birds (0)

Anonymous Coward | more than 7 years ago | (#18915577)

Nah, it's cheaper to use the birds.

And hey, think of all the cool new items crematoriums will now be able to sell. I'd like my grandmother's ashes in the form of an mp3 player!

Re:One nanotube: two birds (1)

iminplaya (723125) | more than 7 years ago | (#18916487)

Yeah but, then we'd take it all out, and we would freeze [slashdot.org] .

The Weirding Way (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18915303)

Ok Slashdot, I'll tell you my first incest experience. It was about 2 years ago; I was 18 and my sister was 16 (and a half). We had a cousin staying at our house for the summer and she was either 16 or 17. Got along great with the cousin, but not so great with the sister. She felt she should have the run of the house since I was about to move out to college and I thought she was a bitch. This caused conflict.

Anyway, the parents were at work, I was chilling in my room, and the two girls were sunbathing/swimming outside. I had nothing for my sister at this point, but my cousin was a different matter. From an objective standpoint, she's good looking. She's the big athlete in the family so the body is pretty good as well. here [tinyurl.com] is a photo, face hidden of course.

Here's where things get crazy. I'm building up jack material on my cousin, but I can't stop looking at my sister. Cousin is hot, but my sister has a RACK. Her boobs look like they wanna bust out of the bikini. So I start storing images of her as well. It feels a little sick at first, but that just makes things more exciting.

I want a closer look, so I go outside to the pool and say that I'm going to bust into the booze cabinet and to come inside if they want any. They think it's a great idea and follow me in. They get wasted pretty fast, but I only have a couple drinks. It gets to the point where they're basically passed out on the floor, wearing skimpy bikinis, and I'm sitting there with a raging hard on. So I make the decision.

I run to the basement to grab a camcorder and set it up in the den where we are. Just then, my grandpa busts through the door, tears off my pants, and fucks me in the ass. He's wearing a cowboy hat. Once he unloads, he runs back out of the house and yells, "I have the weirding way!"

Re:The Weirding Way (-1, Flamebait)

Broken scope (973885) | more than 7 years ago | (#18915315)

Whats worse... your trolling or your lack of originality?

Re:The Weirding Way (0)

Anonymous Coward | more than 7 years ago | (#18915367)

What's worse, your flamebaiting or your lack of a sense of humor?

Obviously, your flamebaiting. Good call. ;)

Re:The Weirding Way (0)

Anonymous Coward | more than 7 years ago | (#18915341)

I love it when a story has a happy ending.

Re:The Weirding Way (0)

Anonymous Coward | more than 7 years ago | (#18916157)

here [tinyurl.com] is a photo, face hidden of course.

pwned

Come again (3, Funny)

Anonymous Coward | more than 7 years ago | (#18915319)

"Extremely long"?

Perhaps 18 mm stands for... 18 million miles?

Re:Come again (3, Funny)

Anonymous Coward | more than 7 years ago | (#18915343)

Perhaps 18 mm stands for... 18 million miles?
18mm is extremely long for most nerds

Re:Come again (1)

antron-jedi (951323) | more than 7 years ago | (#18915523)

poned

Re:Come again (1)

jibjibjib (889679) | more than 7 years ago | (#18915739)

You misspelt "pwned."

Re:Come again (0)

Anonymous Coward | more than 7 years ago | (#18915979)

you misspelt "pwnd"

Re:Come again (1)

Wandering Wombat (531833) | more than 7 years ago | (#18916059)

You misspelled "I'm illiterate."

Re:Come again (2, Funny)

gringer (252588) | more than 7 years ago | (#18917351)

you misspelt "pond"

Re:Come again (5, Informative)

ian_mackereth (889101) | more than 7 years ago | (#18915545)

Just to get some perspective on this, 18mm is about a third of the length of good quality wool fibres.

That puts it in the area of useable length for macro-sized application.

Re:Come again (3, Informative)

evanbd (210358) | more than 7 years ago | (#18915671)

Well, they're still more slippery than wool, so that problem has to be solved too. But this is one piece of the puzzle, and it's very cool to see it coming along.

Spinning into thread (0)

Anonymous Coward | more than 7 years ago | (#18915677)

If a condition must be met before a fibre can be spun into a thread of infinite length, it should be the length-over-thickness ratio of the fibre, not its length. You cannot turn 18mm sided cubes into a thread, but nanotubes, being super thin, require less length. It's like doing the same thing at a smaller scale (imagine shrinking your wool-making equipment).

Re:Come again (1)

miro f (944325) | more than 7 years ago | (#18915901)

wait, so you're saying, the ultimate goal is to be making jumpers and socks out of carbon nanotubes?

Re:Come again (1)

7Prime (871679) | more than 7 years ago | (#18917471)

Let me just put on this nice comfy pair of carbon-nano-tube boxers, before you shoot me in the crotch.

See... the bullet just bounced off... "balls of steel," I tell ya!

Re:Come again (2, Interesting)

electrosoccertux (874415) | more than 7 years ago | (#18916311)

Just to get some perspective on this, 18mm is about a third of the length of good quality wool fibres.



That puts it in the area of useable length for macro-sized application.

IIRC when Popular Mechanics discussed these nanotubes for building our space elevator, one of the technical hurdles they mentioned was needing nanotubes ~18" in length for the structure to be sound.

Obviously we've got a long ways to go then.

The other thing they mentioned was that given a mathematically perfect carbon nanotube structure, the highest building we could build before it would collapse on itself is something like 90 miles; and we need

Of course both of these are hearsay so take them with a grain of salt, but the important thing I remember is that whatever the max height of a carbon nanotube structure that we could build is, the height required for a space elevator/cable is several orders of magnitude greater.

So why were we funding this stuff again?

Re:Come again (1)

catprog (849688) | more than 7 years ago | (#18916923)

What about a rope supported from the top.

Re:Come again (1)

electrosoccertux (874415) | more than 7 years ago | (#18916981)

What about a rope supported from the top.
Yes the figure that referenced as to how high we needed the carbon nanotubes to be able to support themselves structure wise was the number that was "several orders of magnitude" (~3 I seem to recall) higher than what the what the mathematically perfect nanotube structure could reach. That height that we needed the nanotubes to be able to reach structure wise was just as you say-- only far enough so that the rest of the tether could act as a counterbalance to the part of the tether closer to earth.

All in all their estimate of likelyhood was "50-100 years in the future" and to not get too excited about it given the technical hurdles to overcome (not just getting it high enough, but dealing with the vibrations such a long cable would experience, for example; or if we wanted to anchor it to an asteroid we have to get ourselves an asteroid first).

Re:Come again (1)

megamike23 (932627) | more than 7 years ago | (#18916103)

you know that nanotubes are usually on the order of 10-100 nanometers wide, which is 10-100*10^-9 meters, so 18mm would be 18*10^-3 - 6 orders of magnitude difference

Re:Come again (1)

imsabbel (611519) | more than 7 years ago | (#18916825)

Its about 10000 times longer than what you get when you buy single walled carbon nanotubes at a chemical supplier, like alfa aesar.

Thats hardly something to sneeze about.

They are long enough to, for example, actually connect two macroscopic devices, for example two dies on a MCM.

Million times longer than they are wide (1)

Hittite Creosote (535397) | more than 7 years ago | (#18916869)

It's a relative term - extremely long compared to their diameter. These are about a million times longer than they are wide.

As Mork would say... (3, Funny)

sycodon (149926) | more than 7 years ago | (#18915337)

Nano nano nano.

Re:As Mork would say... (1, Informative)

mark-t (151149) | more than 7 years ago | (#18915383)

That's na-NU, my man....

My understanding is that writers originally wrote the it as nano, and so in particular first season merchanise often used that spelling, but Robin Williams pronounced it as nanu.

Re:As Mork would say... (1)

sycodon (149926) | more than 7 years ago | (#18915791)

Yes, but that would not have made much sense in the context of this thread eh? :-)

Re:As Mork would say... (1)

camperdave (969942) | more than 7 years ago | (#18915855)

I'm afraid the only place this conversation would make sense is in alt.tvalien.mork.mork.mork.

Re:As Mork would say... (1)

Cappy Red (576737) | more than 7 years ago | (#18915971)

Isn't that the place where people go to discuss the swedish chef?

Re:As Mork would say... (1)

Wandering Wombat (531833) | more than 7 years ago | (#18916083)

That was actually witty and hilarious. My chef's hat is off to you.

Now where s my space elevator? (0)

Anonymous Coward | more than 7 years ago | (#18915353)

18mm? Can be spun together into longer fibers? Get me to space.

Re:Now where s my space elevator? (3, Funny)

Anonymous Coward | more than 7 years ago | (#18915451)

18mm? Can be spun together into longer fibers? Get me to space.

Forget space. I just want my flying car they promised me ten years ago.

Re:Now where s my space elevator? (1)

QuantumG (50515) | more than 7 years ago | (#18915589)

You are aware that the space elevator is for sending cargo into space right? And the cost of building a space elevator is never amortised into the cost per kg when people are making claims about how much cheaper the space elevator is over rockets.. and have you ever noticed how they always seem to compare the cost of launching cargo on a space elevator built from super strong materials to rockets that are built from today's materials?

The economics of space travel has very little to do with the technology we use to get there, and more to do with the demand for launches.

Re:Now where s my space elevator? (2, Insightful)

confused one (671304) | more than 7 years ago | (#18915885)

It's quite a stretch to go from 18mm to geo-sync orbit, isn't it?!

Re:Now where s my space elevator? (1)

MikShapi (681808) | more than 7 years ago | (#18917111)

It's also a stretch to go from a very big barrel of hydrogen to GEO, and yet it's been proven to get payloads there.

There's nothing particularly revolutionary about any of the physics underlying the SE. Once a point (that is not moving further and further away) of tensile strength (in polymer fabric you can weave, not in the individual material you build it from) is reached, you build it. Period.

If you can make fibers that behave more like thread and less like sand pebbles, you can load more into the fabric, and the strength of the available fabric (per given weight) rises a notch higher.

At some point, it'll reach the elevator-capable point.

ZOMG BOYKOTT R0L4ND!1! (4, Funny)

pestie (141370) | more than 7 years ago | (#18915381)

Did I get it right in the subject line? Apparently all Slashdotters are supposed to hate this Roland guy, right? God, I just want so desperately to be loved...

Re:ZOMG BOYKOTT R0L4ND!1! (1)

sohare (1032056) | more than 7 years ago | (#18915567)

You have done your duty well, comrade.

Re:ZOMG BOYKOTT R0L4ND!1! (2, Informative)

ColaMan (37550) | more than 7 years ago | (#18916631)

While I don't condone his actions in the past (that is, using /. to push more views to his site for personal gain), he doesn't link-through his site anymore. So now, he's just another submitter of crappy stories that generally give off wildly over-optimistic expectations of future possibilities.

Thread mutation into space elevators in (0)

Anonymous Coward | more than 7 years ago | (#18915425)

3,2,1

Wee! (1)

Maekrix (1025087) | more than 7 years ago | (#18915429)

Yay for buckyballs!

That's what she said (2, Funny)

Syberghost (10557) | more than 7 years ago | (#18915433)

(eom)

Quick !! There are "Tubes" afoot !! (-1, Redundant)

unity100 (970058) | more than 7 years ago | (#18915447)

Somebody call Ted Stevens ! this is his expertise area.

They better get to work (0)

Anonymous Coward | more than 7 years ago | (#18915491)

at 18mm It's gunna take a lot of these to make a space elevator

Nano* is cool! (1)

ickyellf (903367) | more than 7 years ago | (#18915497)

Anything with the word "nano" in it is automatically cool. I'm hungry for a nanosandwich and some nanofries, with a nanoCoke to wash it down. The preceding sentence was very cool.

Re:Nano* is cool! (1)

corsec67 (627446) | more than 7 years ago | (#18915515)

And you miss the obvious?

You do that while listening to your Nano? (Ipod Nano, that is)

Re:Nano* is cool! (0)

Anonymous Coward | more than 7 years ago | (#18915721)

> Anything with the word "nano" in it is automatically cool.

"Nanomedicine"? WTF is that??

The general rule is you substitute "micro" wherever the writer used "nano," and see if the sentense still makes sense.

Obviously nanomedicine is just micromedicine on a smaller scale. :)

Re:Nano* is cool! (0)

Anonymous Coward | more than 7 years ago | (#18915935)

Well, I got some microfiber at home and I don't think I can make any type of elevator from it.

Rule #27 - picking on other post results in a typo automatically

One more step toward a space elevator? (2, Interesting)

SeaDour (704727) | more than 7 years ago | (#18915509)

Can these "nanofibers" be used to make a space elevator ribbon? Or does that system require a different method of employing carbon nanotubes?

Re:One more step toward a space elevator? (2, Insightful)

QuantumG (50515) | more than 7 years ago | (#18915569)

Two points I like to make about the space elevator:

This isn't tomorrow's technology, it is something the human race might do a hundred years from now.

If we have the super strong, super light materials needed to make the space elevator, what else might we do with them? Might we not make better rockets? Or better planes? Might we not make single-stage-to-orbit vehicles which so drastically reduce the price of launch costs that building a space elevator is not only possible, but unnecessary?

Re:One more step toward a space elevator? (1)

EllisDees (268037) | more than 7 years ago | (#18915765)

Those would have to be some *drastically* reduced prices to compete with a space elevator. Accelerating to escape velocity is always going to take a lot of fuel, where with the space elevator it's not even an issue.

Re:One more step toward a space elevator? (4, Interesting)

camperdave (969942) | more than 7 years ago | (#18915815)

Might we not make single-stage-to-orbit vehicles which so drastically reduce the price of launch costs that building a space elevator is not only possible, but unnecessary?

The problem with rockets has never been the mass of the rocket, but the mass of the fuel. There's only so much oomph you can get out of a million litres of hydrogen and oxygen chemically, and it's only marginally more than the power it takes to lift a million litres off the surface and into space. Sure, a lighter fuel tank, and lighter payload will help, but not significantly.

No, if we want cheap access to space, we either go nuclear [nuclearspace.com] , or build some sort of space elevator. While we may just be at the threshold of being able to make materials with the tensile strength needed for a beanstalk, we have the tech to make gas core nuclear rockets right now.

Re:One more step toward a space elevator? (4, Insightful)

evanbd (210358) | more than 7 years ago | (#18915943)

It's not about the fuel prices. Never has been, and won't be for the foreseeable future. Propellant is cheap, it's the vehicle that's expensive. Elon Musk of SpaceX was recently quoted as saying propellant costs are comparable to the accounting errors.

Remember that the space elevator has to supply all the energy to the payload too, but it has to get it in a much more expensive form -- like electricity beamed from the ground by lasers or some such. Rockets aren't actually all that energy inefficient in comparison.

I used to be a huge fan of the space elevator idea, but then I started looking what those same materials do to rockets. SSTO is just the start. And remember, those materials will change rockets long before they make a space elevator.

Of course, I am a rocket engineer, so I might be a little biased, but I've also examined the problem in some detail :)

Re:One more step toward a space elevator? (0, Insightful)

Anonymous Coward | more than 7 years ago | (#18916165)

You can not be a "rocket engineer" and seriously believe what you just said.

The price of the fuel is not what makes rockets inefficient, it's the mass. X amount of the best available rocket fuel can only barely lift the X amount of mass to orbit in a single stage. Even if the vehicle had zero dry weight due to being built of solid unobtainium, the amount of payload to orbit would be miniscule in comparison to the mass of the fuel. Most of the fuel is spent moving the fuel rather than moving the payload. Try looking up the term "mass ratio"...

A space elevator, assuming one could be constructed, would only need the energy that it takes to move the payload alone rather than payload+fuel. This alone would result in hugely massive energy savings. Also, a space elevator can be run at an arbitrary speed so it'd be possible to lift huge payloads (say, one-piece space station) with little power given enough time. Even solar panels would be a viable energy source for unmanned loads.

The only advantage rockets have is speed, which only matters for manned missions. In a world with space elevators, small rockets would probably still be used to transfer people between ground and orbit while commercial satellites, big interplanetary spacecraft etc would go up slow and cheap on the elevator.

Re:One more step toward a space elevator? (3, Informative)

evanbd (210358) | more than 7 years ago | (#18916787)

People don't seem to get this somehow. Yes, mass ratio matters. A lot. Let's look at LOX+Kerosene, a very typical combination in many ways. You get an ISP of about 3000 m/s in a medium-high performance vacuum engine (the case for most of the way to orbit). LEO takes about 9000 m/s of delta-v by the time you account for aerodynamic and gravity losses. That means the mass ratio of your rocket needs to be about e^(9000/3000) = e^3 = 20. So 5% of your rocket makes it to orbit. Yup, that sucks. LOX costs about $0.07/lb in bulk, kerosene about $0.30. So propellant costs are about $0.15/lb for propellant, or $3/lb of orbited mass.

Now lets look at the space elevator. Climbing to geosynchronous orbit is equivalent to about 8000 m/s of delta-v (roughly... don't have the exact number off hand and I don't feel like calculating it). From 1/2M*v^2, that's 32MJ/kg. That's about the energy you get from burning 6 kg of LOX-kerosene. So from an energy equivalence standpoint, you're using 6 kg of propellant worth of energy instead of 19 -- a factor of 3 improvement.

The problem with the space elevator is twofold. First, the required *form* of the energy is different. You can't just use cheap hydrocarbon fuels -- you have to convert it to electricity, and then get that electricity up to the elevator either by beaming it or along wires, and neither option is efficient in the slightest. In fact, by the time you turn the hydrocarbon fuel into electricity and then get it to the elevator car, you're under 50% efficient; being as high as 30% would take a lot of work and be quite impressive. But the rocket was 30% efficient! Space elevators are *not* particularly more efficient than rockets.

The second problem is the infrastructure of the space elevator -- the required capital investment for a certain payload rate (kg delivered per day) is higher than for the rocket (we won't even discuss non-reusable rockets). Even if you got the space elevator more energy-efficient than the rocket, this fact combined with the slower transit time, the geosynchronous orbit as the only one available, and the more complicated technological requirements, the rockets win.

Yes, the space elevator tech is harder. The ribbon itself and the beamed power are the obvious examples, but there are others. For example, the tires on the car that work against the ribbon -- you need tires that run at about Mach 3 and are good for 27000 miles. That's not even remotely easy. You need motors that have higher power to weight ratios than currently exist. Etc, etc, etc. Rockets, in comparison, are easy. Especially if you have space-elevator class building materials available -- at that point you can do SSTO with pressure fed rockets, and get rid of the pumps altogether -- the pumps being the hardest part of rocket engine development by far in a conventional design.

When people say that for space elevators you only have to provide the energy to climb up, and aren't wasting the energy carrying propellant, they often forget that it's actually a *lot* of energy to climb up, and that rockets are actually remarkably good at converting available chemical energy into exhaust kinetic energy -- some are better than 80% efficient by that metric.

Re:One more step toward a space elevator? (1)

catprog (849688) | more than 7 years ago | (#18916959)

You do not need to use your electric motor to accelerate to escape velocity. You gain escape velocity by moving along the ribbon and then using the earth's rotation to accelerate. What about using coal for the electricity? Why do the tyres need to run at Mach 3 if you run the climber at say Mach 0.5? For that matter why do you need tyres(look at chair lifts. The wheelhouse at either end)? For power to weight ratios look at the solar planes or solar cars? (You only need a motor that can loft itself for it to work. Economically you would need better though)

Re:One more step toward a space elevator? (1)

evanbd (210358) | more than 7 years ago | (#18917253)

The whole thing is about economics. You want high speed for short transit times, obviously, but the important reason is to get the car off the bottom of the elevator. You need to do this because of the weight limit on your cable. Once the car is a ways up it counts less against the weight limit. This implies high speed tires, high power motors, and high power transmission rates. The reason I say Mach 3 is nothing magic, just that many elevator proponents talk about speeds around 1000 m/s.

Even if your car "only" goes at 100 m/s, that's 1kw of power *per kilogram* of mass (elevator + payload), or about 1/2 HP per pound -- which is close to the weight of current electric motors, let alone the car and payload. The power to weight isn't required to loft the car, it's required to loft it quickly. And don't forget, you have to cool the motor -- a task that gets harder in vacuum.

You still actually need to put a lot of energy into climbing. The first 1000km, where centripetal acceleration isn't helping much and gravity is still high, means about 1E6m * 10 m/s^2 or about 10 MJ/kg. Total energy is well more than that, I think about 30MJ/kg. I don't have the exact number handy, but it's big.

The problem with solar cells and any number of other power technologies is, again, power to weight and therefore elevator car speed.

I'm not trying to say any of this is impossible -- just that the challenges make rockets look really easy, especially if you have space elevator class materials available; and rockets aren't really all that inefficient from an energy standpoint, once sad materials are available to improve the mass ratio a bit.

Re:One more step toward a space elevator? (1)

imsabbel (611519) | more than 7 years ago | (#18916865)

If you are really a "rocket engineer" (what kind, 4th of july ones?), then you have a really narrow horizon.
Try to imagine how many launches you would need to, for example, build a mining and refining base on an asteroid. 25 million tons, in an escape orbit, anybody?
Thats a 1000 times of all launches in human history, for something that might be just a little thing if we ever go interplanetary.
Try a quick calculation of how it would cost...

You might be thinking in current terms "All we send up is highly technical stuff that costs 50k to produce vs 8k to list, to rocket costs arent the limiting factor", but think about getting bulk material up there...

Re:One more step toward a space elevator? (1)

Hatta (162192) | more than 7 years ago | (#18916037)

While we may just be at the threshold of being able to make materials with the tensile strength needed for a beanstalk, we have the tech to make gas core nuclear rockets right now.

Do we have the tech to deal with the fallout of the inevitable accidents?

Re:One more step toward a space elevator? (1)

Telvin_3d (855514) | more than 7 years ago | (#18916169)

yeah, and 'fallout' is the right choice of word.

Re:One more step toward a space elevator? (1)

TEMMiNK (699173) | more than 7 years ago | (#18916145)

The problem being that you put the words Nuclear and Rocket together and the Russians get really nervous, and nobody likes a nervous nuclear power.

Re:One more step toward a space elevator? (1)

init100 (915886) | more than 7 years ago | (#18916319)

we have the tech to make gas core nuclear rockets right now.

With nuclear rockets, you would have to solve vast PR problems though. Just consider the demands by the greens to close nuclear power stations, which are firmly on the ground. A nuclear-powered rocket, with the significant risk of an accident and its fuel being released into the environment, could face much more severe problems than nuclear power stations.

Even to me, who is usually pro-nuclear, it isn't clear that nuclear rockets launching from the surface of the earth is a good idea. Considering the history of modern rocketry, we've had quite a number of accidents with ordinary chemical rockets, and it would be naive to assume that accidents wouldn't happen to those nuclear rockets. Nuclear rockets launching from orbit. such as on interplanetary missions, is a very different matter, which is do not oppose at all. There is a problem though: How do we get the nuclear fuel to orbit without the risk of a serious accident?

Re:One more step toward a space elevator? (1)

CrtxReavr (62039) | more than 7 years ago | (#18915865)

This isn't tomorrow's technology, it is something the human race might do a hundred years from now.

I think you're wrong about that, as do the people doing most of the research on the subject.

In this discover.com article [discovermagazine.com] covering Brad Edwards' NASA-sponsored research into Space Elevator technology, his completed work under a $500,000 NASA research grant reveals the technological and economic feasibility of space elevators.

Re:One more step toward a space elevator? (1)

tsa (15680) | more than 7 years ago | (#18916423)

A space elevator contains so much carben we should build it just to get rid of our pesky global warming problem. Grow plants to take the CO2 out of the air, turn them into space elevator, and Bob's your uncle!

Re:One more step toward a space elevator? (0)

Anonymous Coward | more than 7 years ago | (#18915679)

A couple thoughts...

If these dealies conduct electricity well, then couldn't a huge electrical conductor sticking out into space maybe be, um... bad? Somehow?
Like, I dunno... "space lightning" or something? Aliens being able to dock and suck out all of our precious life energy?

Although a space tether thingie might also generate a lot of static electricity or something, maybe it should be grounded.

But then, that thing has to be HUGE... where to get all the carbon for the nanotubes? But then again, locking up all that carbon, maybe there's a solution to global warming here!

but doh... with it being a giant space lightning rod, it would just keep introducing MORE energy into earth's system. Feh.


This is some killer weed.

Re:One more step toward a space elevator? (0)

Anonymous Coward | more than 7 years ago | (#18916495)

the nanotubes (they are double walled nanotubes not nanofibers) can be used to make a space elevator ribbon. The goal is that they will be woven into a nanotube yarn. Maybe someday.

Re:One more step toward a space elevator? (1)

richard.cs (1062366) | more than 7 years ago | (#18917523)

This was pretty much my first thought when I read the summery. IIRC the tensile strength of carbon nanotubes is more than sufficient to make the ribbon but up until now they have all been extremely short and thus difficult to make a ribbon from. I don't have the book on me at the moment so I can't check this figure but I think about 4mm was the point that it started to become feasible.

Carbon fibre (3, Interesting)

TapeCutter (624760) | more than 7 years ago | (#18915519)

Apart from more tubes for the interwebs, I would imagine that 18mm is also long enough to make carbon fibre products that are lighter and stronger than what is currently available. I wonder if an America's Cup or F1 winner will one day be built from nanotubes?

Re:Carbon fibre (2, Interesting)

evanbd (210358) | more than 7 years ago | (#18916939)

Note that nanotubes != CF.

That said, people are already starting to incorporate nanotubes in composite materials. The two hard parts are that they're really slippery and it's hard to get the matrix to stick to them, and that they tend to clump up a lot. The increased length helps with the first problem -- slippery is less of a problem if there's more surface to stick to. I don't know about the dispersion.

Nanotube composites are already impressive. You can get things with 30-50% more stiffness, 50-200% more thermal conductivity, lower thermal expansion, and other useful properties. Metal matrix composites are also impressive. Think aluminum with nanotubes added. You can get double the strength, more than double the stiffness, and double or more the thermal conductivity in something as machinable as aluminum by adding only 1-2% nanotubes. This is a *rapidly* advancing field, and it's poised to seriously change high end materials science in the very near future.

Rewiring issues (0)

Anonymous Coward | more than 7 years ago | (#18915529)

...could one day replace copper wires.
I can see where this would be bad for home wiring.

"DAMN! ... that salesman told me these wire cutters would cut through -anything-"

18 mm... Great! (3, Funny)

camperdave (969942) | more than 7 years ago | (#18915563)

18 millimetres? Great, only 99,999.999982 km to go!

Re:18 mm... Great! (1)

Snarfangel (203258) | more than 7 years ago | (#18915925)

Perhaps it'll be like Moore's law. If the length doubles every 18 months, it'll less than half a century.

Rmo3 up (-1, Troll)

Anonymous Coward | more than 7 years ago | (#18915599)

World's Tallest Midget (1, Funny)

Luyseyal (3154) | more than 7 years ago | (#18915617)

In other news, Bjorn Stevens, world's tallest midget, and jumbo shrimp decry military intelligence in Iraq peace action.

-l

Re:World's Tallest Midget (1)

tmosley (996283) | more than 7 years ago | (#18916655)

Thunderous silence as /. does not undertand oxymorons.

Jsponnge (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18915651)

the top. Or were, FreeBSD used to there are only

Great... (3, Funny)

DoofusOfDeath (636671) | more than 7 years ago | (#18915707)

Now we're going to get spam advertising ways to lengthen our nanotubes...

The real killer commercial application (2, Interesting)

mad zambian (816201) | more than 7 years ago | (#18915753)

will be when someone figures out how to either join these fibres together, or grow a continuous nano-scale monofilament.
Then we will really see what Arthur C was talking about.
The applications for "diamond" fibre are enormous.

some perspective (4, Informative)

Goldsmith (561202) | more than 7 years ago | (#18915881)

Although the PR person who wrote this obviously thinks this is a major breakthrough, these guys are using a method which was originally invented by Japanese researchers three years ago (google for "CNT super growth"). The Japanese guys have since focused on getting the fastest growth rate possible (I think it's about 0.2mm/min... if you want to figure out how many, many years it would take to grow a space elevator). There are lots of people working on improving this growth method, 18mm arrays may be the longest, but it seems to be in the same range as other people working on the "super growth" method. That doesn't diminish this research, rather it means that this method is very likely to work in the long run for industrial scale growth of nanotubes for materials (more simply, it's easily reproducible, and people want "nano-enhanced" golf clubs).

Isolated nanotubes have been grown longer than this (I've grown isolated nanotubes longer than this, and I'm not a growth specialist), as have bundles of nanotubes. This is the longest array of pure, aligned, continuous nanotubes.

a clarification (1, Informative)

Anonymous Coward | more than 7 years ago | (#18916101)

This is not the record for longest tube ever grown. Groups have grown single tubes the size of their substrate wafers (4 inches usually). This group grew a long bundle of CNTs. In the field we call these 'forests'--imagine a lawn, but at the nanoscale. The blades of grass are the CNTs poking up off the surface.

Remember also that the figure of merit of a CNT when used for its mechanical properties is the growth defect density per meter, and even for the best growth techniques so far this ends up being a number like 1 every 10 microns (10^-6 m).

This means that for something such as a macroscopic cord, not only would one have to grow incredibly long CNTs, they would also have to be nearly defect-free in order to satisfy the (nearly magical) strength requirements attributed to them by many people.

mod uP (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18916139)

need your help! PrefeRrably with an smells worse than a for *BSD because questions, then our cause. Gay have an IRC client

Tag: Biotech (1)

0123456789 (467085) | more than 7 years ago | (#18916161)

I don't normally complain about mods/tags etc (seems a bit pedantic), but how did this get tagged as 'biotech'?

Is the word 'carbon' enough to be classified as 'biotech'? Is a pencil 'biotech' now?

RTFA (2, Informative)

Raynor (925006) | more than 7 years ago | (#18916389)

It would be nice if people actually read up the subject before posting this garbage...

This is not "The World's Longest Carbon Nanotubes." It's the longest mass-producable parallel carbon nanotubes.

Great... (1)

LynnwoodRooster (966895) | more than 7 years ago | (#18916661)

Now some Inanimate Carbon Tube will win Employee of the Week before I do...

H. J. Simpson

Space Elevator Progress Report anyone? (1)

MikShapi (681808) | more than 7 years ago | (#18917147)

Here's what I remember from last time...

To be held up, a space elevator needs a FABRIC with a tensile strength of about 65GPa.
To build it, you'd want a safety factor of about two, thereby a tensile strength of about 120-130GPa.

I do not know the specs of the tubes from TFA, however

Very short INDIVIDUAL single-walled carbon nanotubes have been created (in a lab, in small quantities, using processes that may be prohibitively expensive) with measured individual fiber strength of about 60GPA.
"Very long" ones were (previously) created at about 1cm with substantially lower tensile strength (circa 4GPA if memory serves me right).
The last several years were spent by industry leaders in this field ramping up production of CNI by several orders of magnitude, whereas bulk availability made prices of CNI go down orders of magnitude.

Existing processes of weaving tubes into a fabric involve loading the fabric with ~5+% of CNI. The last Elevator2010 competition saw competition tethers in the 4GPA ballpark (using fibers in the 30-60GPa ballpark I'm guessing), none of which could beat the commercially-available "house tether".

This is all layman talk of an enthusiast, not a professional. I'm a coder/syadmin gone biochem, not an engineer. If someone a bit less clueless than me can correct and/or bring this up to date (some of what I recited here I've acquired ~3 years ago, things would have progressed since then), I think we'd all be the wiser.

Cheers.
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