The nanotubes may become longer lasting by using bundles of nanotubes:
Arrays of Bundles of Carbon Nanotubes as Field Emitters.
NASA’s Jet Propulsion Laboratory, Pasadena, California
Thursday, 01 February 2007
Area-averaged current densities exceed those of arrays of single nanotubes.
"Experiments have shown that with suitable choices of critical dimensions,
planar arrays of bundles of carbon nanotubes (see figure) can serve as
high-current-density field emitter (cold-cathode) electron sources. Whereas
some hot-cathode electron sources must be operated at supply potentials of
thousands of volts, these cold-cathode sources generate comparable current
densities when operated at tens of volts. Consequently, arrays of bundles of
carbon nanotubes might prove useful as cold-cathode sources in miniature,
lightweight electron-beam devices (e.g., nanoklystrons) soon to be
developed."
http://www.techbriefs.com/component/...-sciences/1206
And in any case you don't need to use the nanowires as electron emitters to
get the ionization effect. You get it as well from the intense electric
fields generated by wires at the nanoscale in accordance with Peek's Law:
https://en.wikipedia.org/wiki/Peek%27s_law
Note it may be the nanoscale wires might not even need to be carbon
nanotubes. According to Peek's Law simply being at nanoscale diameters is
sufficient to generate the intense fields. Since there is much research
ongoing with metallic nanowires they as well could be used to confirm the
better efficiency of ionic propulsion with wires at the nanoscale.
In regards to getting longer nanotubes by tying them together, that has
already been confirmed experimentally by a team at Rice University, the
leading center for nanotechnology in the U.S. That research was published in
Nature Materials, the associated journal in materials science to Nature, the
leading science journal in the world. The Rice team was able to show simply
tying nanotubes together produced longer nanotubes of greater current
capacity than the copper or aluminum wires now in use and at lighter weight.
About the power requirements, the ionic propulsion with ionizing wires,
called corona wires, at the nanoscale has improved power-to-thrust ratio.
Then the needed power can be supplied by onboard batteries.
Bob Clark
----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:
Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------
"John Larkin" wrote in message
...
On Tue, 1 Nov 2016 11:09:13 -0400, "Robert Clark"
wrote:
Nanotechnology makes possible an "ion drive" for air vehicles analogous to
the famous ion drive of NASA's deep space probes:
Carbon nanotubes for "Ionic Wind" Craft or "Ionocraft".
Clark R*
Department of Mathematics, Widener University, USA
Review Article
Volume 1 Issue 2 / Received Date: September 26, 2016 / Published Date:
October 20, 2016
Abstract
Peter Thiel of the Founders Fund once famously said, "We wanted flying
cars,
and we got 140 characters."But nanotechnology now does make possible the
long desired flying cars. It's a different propulsion method though than
propellers or jets however. It's propulsion by electric fields known as
electrohydrodynamic propulsion (EHD). It works by ionizing air then using
electric fields to propel the charged air molecules rearward, thus
producing
thrust. It's quite analogous to the famous space ion drive of NASA. EHD has
been known at least since the sixties. Its problem is, as with ion drive,
the thrust is so low. So far the EHD craft have not been able to lift both
themselves and their power supplies. The ones made so far leave the power
supply on the ground and connect to the craft through power cables. But the
equations of EHD suggest the thrust for the power required gets larger for
thinner ionizing wires. In fact if the wires are at the nanoscale then this
important thrust-to-power ratio can be a hundred times higher than for the
craft constructed so far. This would be enough to lift the craft and the
power supply. This research is to prove what the mathematics suggests. Note
that if it works then all propeller and rotor driven craft become obsolete.
Also, intermediate range automobile travel would be taken over by the EHD
craft, so a large proportion of carbon-emissions would be eliminated,
replaced by this zero-emission travel method. In regards to space
propulsion, since EHD is so similar to ion drive, using components at the
nanoscale may also work to improve the thrust of ion drive. This would be
important to shortening the flight times of spacecraft using such drives.
This is important not just for robotic spacecraft but also satellites that
use such ion drives to reach their final GEO destinations. As it is now,
the
ion drives used have such low thrust it takes months for such satellites to
reach GEO, resulting in millions of dollars of lost revenue to the
satellite
companies. Being able to increase the thrust of these drives would reduce
the flight time, and therefore reduce this lost revenue.
Keywords: Electrohydrodynamic propulsion; Carbon nanotubes; Nanowires;
Ionic
wind; Ionocraft; Plasma drive
https://medwinpublishers.com/NNOA/vo...=23&issueId=63
Bob Clark
Post again when Chevy dealerships are selling flying cars.
Carbon nanotubes are the idiotic craze of the day, and are pretty much
useless so far. As electron or ion emitters, they quickly destroy
themselves.
And they still don't violate conservation of energy. Where is all the
zero-pollution power going to come from?
----------------------------------------------------------------------------------------------------------------------------------
Finally, nanotechnology can now fulfill its potential to revolutionize
21st-century technology, from the space elevator, to private, orbital
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:
Nanotech: from air to space.
https://www.indiegogo.com/projects/n...ce/x/13319568/
----------------------------------------------------------------------------------------------------------------------------------
That's hilarious, tying tiny nanotubes together with fancy knots.
The nanotech bubble popped roughly 10 years ago. I was involved with
academics and inventors and slimy VCs all hoping to cash in on the
upside of the Next Big Thing.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
---