From: "Gary Britt" 

How can something in the physical universe be truly one dimensional as
stated in the article below??

Gary

"Rich Gauszka"  wrote in message
news:44803d2a{at}w3.nls.net...
> looks like carbon nanotubes and a space elevator will only be a dream of
> science fictions writers - sigh
>
> http://news.yahoo.com/s/space/20060602/sc_space/nanotubesmightnothavetheright
stuff
>
> Scientists and science fiction fans alike have big plans for carbon
> nanotubes; it has been hoped that a cable made of carbon nanotubes would
> be strong enough to serve as a space elevator. However, recent
> calculations by Nicola Pugno of the Polytechnic of Turin, Italy, suggest
> that carbon nanotube cables will not work.
>
> American engineers worked on the problem in the mid-1960's. What type of
> material would be required to build a space elevator? According to their
> calculations, the cable would need to be twice as strong as that of any
> existing material including graphite, quartz, and diamond.
>
> Science fiction writer Arthur C. Clarke recognized the materials problem;
> his ingenuity was equal to the task of creating just such a material. In
> his excellent 1978 novel The Fountains of Paradise, he thought up a
> special form of carbon, something called a "continuous pseudo-one
> dimensional diamond crystal," to serve as the cable material. To the
> delight of sf fans and aerospace engineers, Japanese researcher Sumio
> Iijima (at NEC) discovered carbon nanotubes, which are one-dimensional
> carbon fibers exhibiting strength 100 times greater than that of steel at
> one sixth the weight, and high strain to failure.
>
> In something of a "downer" for space elevator fans, Pugno
has calculated
> that inevitable defects will greatly reduce the strength of any
> manufactured nanotubes. Laboratory tests have demonstrated that flawless
> individual nanotubes can withstand about 100 gigapascals of tension;
> however, if a nanotube is missing just one carbon atom, it can reduce its
> strength by as much as thirty percent. Bulk materials made of many
> connected nanotubes are even weaker, averaging less than 1 gigapascal in
> strength.
>
> In order to function, a space elevator ribbon would need to withstand at
> least 62 gigapascals of tension. It therefore appears that the defects
> described above would eliminate carbon nanotubes as a usable material for
> a space elevator cable. Pugno will publish his paper in the July edition
> of Journal of Physics: Condensed Matter. Nanotube enthusiasts counter that
> ribbons made of close-packed long nanotubes would demonstrate cooperative
> friction forces that could make up for weaknesses in individual nanotubes.
>
>

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