Re: Can we now build the space elevator?

From: Neil Farbstein (protologics_at_worldnet.att.net)
Date: 09/24/04 

Date: Fri, 24 Sep 2004 00:17:02 GMT

I have devised several methods of manufaturing Ultra Lng carbon nanotubes.
This is disussed in greater detail on
http://www.vulvoxnanobio.tripod.com
Ajayan's process worked in the laboratory but it is not practical. Vulvox
Nano/Biotechnology is researching and developing practical processes to
manufacture ULNTs (Ultra Long Carbon Nanotubes) Vulvox also has plans to
make HTS superconducting nanotube cables and generators. Read my interview
published by Nano Investors News the link is on the homepage of the above
link.
"Robert Clark" <rgregoryclark@yahoo.com> wrote in message
news:832ea96d.0408290701.4b861045@posting.google.com...
> ============================================================
> From: Robert Clark (rgregoryclark@yahoo.com)
> Subject: Re: beanstalks (was Re: Metallic hydrogen ...)
> Newsgroups: sci.physics, sci.astro, sci.space.policy, sci.materials,
> sci.energy
> Date: 2004-06-09 02:06:53 PST
>
>
> henry@spsystems.net (Henry Spencer) wrote in message
news:<HyzyFx.DIH@spsystems.net>...
> > ...
> > Given that the nanotubes themselves are far thinner than even a
one-micron
> > ribbon, any material technology that ties them together into bulky
> > materials should work just as well for such ribbons, with some
adjustment
> > in the details of manufacturing. Even such a ribbon *is* a bulky
> > material, when the fibers involved are nanotubes.
> > ...
>
> Tie?
> Hmmm. Do you think it might work to tie the ends together of the 20
> centimeter long nanotubes already produced?
> Looking up some links on knots, the knotted ropes always have less
> strength than the single, unbroken ropes. I confirmed this by testing
> on sewing thread.
> Still it might be interesting to find out how strong they are
> compared to single nanotubes.
>
>
> Bob Clark
> ============================================================
>
> Testing with thread confirmed that a break always occurred where two
> strands were tied together. However, to estimate the strength of a
> single strand of thread, I wrapped two ends around my fingers and
> found that the break occurred in the middle of the thread, not where I
> was holding the thread. My guess was that the softness of my fingers
> prevented the thread from breaking at the attachment point (where I
> was holding it.) I confirmed this by holding one end by a pair of
> pliers and the other end with my fingers. The break occurred where the
> pliers held the thread. However, when I put a soft cloth between the
> thread and the pliers, the break occurred in the middle of the thread,
> as when I was holding both ends with my fingers.
> I imagine this must actually be a common way of testing tensile
> strength. That is, you don't want to attach the strand or rope to
> something that will make the rope break at the attachment point. This
> would give an invalid measure of the rope strength. You want it to
> break somewhere in the middle.
> I therefore suggest connecting together the already produced 20
> centimeter long nanotubes with a soft material or by whatever means
> used to insure nanotubes don't break at the attachment point during
> tensile strength testing. This will allow the full strength of the
> nanotubes to be maintained even when they are connected together.
> What will need to be investigated is what soft material will also be
> light enough so as not to cancel out the weight savings of using the
> nanotubes. Note that this soft material might be heavier than the
> nanotube material but because it only has to be used at the
> connections it can be quite small so quite conceivable may only add
> minimally to total weight.
> It still needs to be confirmed that the macroscopic sized nanotubes
> really are as strong as the nanotubes tested on the microscale.
> This report showed that 20 centimeter interwoven strands were
> significantly weaker than the tested individual microscale nanotubes:
>
> Direct Synthesis of Long Single-Walled Carbon Nanotube Strands.
> Science, Vol 296, Issue 5569, 884-886 , 3 May 2002
> http://www.sciencemag.org/cgi/content/full/296/5569/884
>
> However, the theory is that this is because there were many single
> nanotubes connected together by weaker van der Waals forces rather
> than the stronger carbon-carbon molecular bonds that prevail in
> individual nanotubes. This is explained here:
>
> Pulling nanotubes makes thread
>
http://www.trnmag.com/Stories/2002/103002/Pulling_nanotubes_makes_thread_103
002.html
>
> What still needs to be tested is the strength of the *individual*
> nanotubes that make up these 20 centimeter long strands.
>
>
> This article describes a group that proposes that competively offered
> prizes could make possible the technologies required for the space
> elevator by 2010:
>
> Space elevator contest proposed.
> 'Elevator:2010' aimed
> at encouraging technology development.
> http://www.msnbc.msn.com/id/5792719/
>
>
> Bob Clark

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