Re: Check this *** out, as the inbred Southerner said as his famous last words.

On 23 Aug 2005 15:08:51 -0700, "Dan Lenski" <dlenski@xxxxxxxxx> wrote:
>Jasper Janssen wrote:

>> Yeah, but carbon nanotubes, man! NANOTUBES!
>>
>> Kidding aside, it turns out to actually only be .5 mm nanotubes that are
>> more or less woven together like cotton wool, rather than actual larger
>> nanotubes. If you could do the same with 1 cm long nanotubes, though, I
>> have no doubt whatsoever you'd get a stronger material than regular carbon
>> fiber.

>Absolutely right. I work with nanotubes every day, and I can tell you
>that tubes longer than 1 mm or so cannot be mass-produced at this time.
> This definitely limits the strength of nanotube composite materials.

It's just engineering, though, isn't it? Sooner or later we'll figure it
out. When we can make arbitrarily long carbon nanotubes, we can build a
space elevator. When we have a space elevator, we can get rid of spent
nuclear reactor fuel safely and cheaply (not to mention doing nifty things
like asteroid mining economically). When we can do those things, we can
shut down all or most of our earthbased fuel and mining operations, as
well as most heavy industry. And Greenpeace will still be violently
against it.

Whoo, eco-rantage!

>Another problem is that these materials include, along with all the
>carbon nanotubes, a big bunch of amorphous carbon junk which doesn't do
>much for strengthening the composite.

The process they describe for making this material seems to pretty much
presuppose a supply of pure carbon nanotubes -- if I get it right, they
have a surface that is filled with the buggers, standing packed like
herrings in a tun, standing room only, and they knock over one part after
that, like dominoes, keeps knocking over the next bit as it's drawn out by
the mechanical feed.

Using 1 mm tubes instead of .5 would already double the strength of the
stuff, I'd imagine, incidentally.

>But the field is progressing rapidly. I would not be surprised to see
>a carbon nanotube composite bike frame 5 years from now...

Just give me a space elevator within my lifetime. I've still got half a
century in me, I would hope, so it should be doable.


Jasper
.