From: (Paul F. Dietz)
Subject: Re: beanstalk cable
Date: Wed, 01 Jan 1997 17:54:20 GMT
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Lines: 61
Message-ID: <5ae8bu$>
References: <5a296e$> <> <5ae6li$>
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More information on nanotubes and related carbon structures can
be found at

which contains:

"R. E. Smalley Presentation 
 From Balls to Tubes to Ropes: New Materials from Carbon 
 American Institute of Chemical Engineers 
 South Texas Section 
 January Meeting in Houston - January 4, 1996"

Some excerpts:

"One of our long-term dreams is to make electrically conductive cables
out of these buckytubes. For such cables there may well be a quantum
confinement effect that sharply reduces the resistance, to give an
electrical conductivity in such a cable at room temperature that is
dramatically higher than copper - perhaps 10-100 times higher, even
neglecting the remote possibility that these doped buckycables may be
superconducting. So these would really be neat, if we could find ways
of making them in continuous lengths, cheaply, and in large amounts."
"Actually we are confident that with our current optimizations of the
process we are now typically over 70% yield of all the carbon
vaporized into what appear to be perfect buckytubes."
"Arthur Clarke, as many of you know, is abnormally good as a science
fiction writer in making sure that the science part of what he writes
is, at least, not demonstrateably wrong. He has done a very careful
piece of work in this book in the details of this space elevator idea.
For the purpose of the book he assumed the filament (he called it a
hyperfilament) was made of diamond. This slide is virtually illegible,
but trust me. In the upper left hand corner there is a note to me from
Arthur Clarke. He acknowledges he made a small mistake - it shouldn't
have been a diamond cable, it really should have been a buckycable.

The predicted strength of such a perfect fullerene tube cable turns
out to be about 1.5 times stronger than a hypothetical diamond cable,
using the accepted Young's modulus and the assumption that the final
failure mechanism is simultaneous breakage of all bonds throughout the
cross-section of the cable. Actually the failure mechanism of a 1015
multifilament cable which has only van der Waals cohesion between the
filaments is going to be a lot closer to the ideal than a diamond
cable would be. You can imagine that it would be much easier to have a
stress fracture in a cable made of diamond, no matter what sort of
lamination or filamentation is done. The dangling bonds on the surface
of the diamond lattice will need to be terminated with hydrogen atoms.
These will be "rubbed off" as the cable flexes, and the filaments or
lamina will fuse together. Buckytubes, in comparison, don't need any
hydrogen to stabilize the surface. They are perfectly fine just the
way they are."

Lots more good stuff at that site.