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-Department of Electrical & Electronics Engineering

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Introduction

The nascent field of nanotechnology is attracting increasing attention fromelectrical engineers. The field of nanotechnology, which at this point is reallyonly nanoscience, has only recently gained legitimacy.

All signs indicate, however, that it is poised for robust growth during thecoming decade. One of the problems with this subject, however, is that there islittle agreement on what constitutes nanotechnology.

Some (including Intel) refer to nanotechnology as any technology that utilizes

components smaller than 100 nanometers. Others have more radical visions ofnanotechnology. These proponents foresee molecular assemblersbuilding computers that are millions of times faster than current computers.

If Moore's Law is to have any chance of continuing past 2010, electrical

engineers will need to continue to make rapid progress in molecularnanotechnology.

http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.foresight.org/http://www.foresight.org/http://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.aeiveos.com/~bradbury/Authors/Engineering/Drexler-KE/NaFS.htmlhttp://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.foresight.org/http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046http://www.theworkcircuit.com/story/OEG20030127S0046

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Sheets, balls and

armchairsIf Moore's Law is to have any chance of continuing past 2010,electrical engineers will need to continue to make rapid progress in

molecular nanotechnology.This free electron gives graphite its electrical conductivity, whereasdiamond does not conduct electricity. This structure can bedescribed as sheets of carbon piled one on top of the other.

The carbon bonds make a sheet a very strong structure, yet the

forces connecting the sheets themselves are weak. These are thetwo properties of graphite sheets that make them especially useful innanotechnology; their strength and electrical properties.

A buckyball (buckminsterfullerene) is a molecule containing 60carbon atoms that close up to form a sphere bout 1 nm in diameter.

Each carbon atom is bonded to three others, as in graphite.

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Researchers found that by adding just a few percentage points ofvaporized nickel nanoparticles to the vaporized carbon, using eitherabove mentioned methods, they can make more nanotubes thanbuckeyballs.

This method produces both SWNT and MWNT mixed in the carbonsoot. There are three methods that various companies havedeveloped to produce carbon nanotubes in bulk quantities and at alower cost.

The first method is called high-pressure carbon monoxide

deposition, or HiPCO. This method involves a heated chamberthrough which carbon monoxide gas and small clusters of iron atomsflow.

When carbon monoxide molecules land on the iron clusters, the iron

acts as a catalyst and helps a carbon monoxide molecule break upinto a carbon atom and an oxygen atom.The carbon atom bonds with other carbon atoms to start thenanotube lattice and the oxygen atom joins with another carbonmonoxide molecule to form carbon dioxide gas, which then floats off

into the air.

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Graphene modelGraphene isan allotrope of carbon. Its

structure is one-atom-thick planar sheets of sp2-bonded carbon atoms that are

densely packed in ahoneycomb crystal latticeGraphene differs from mostconventional three-dimensional materials. Intrinsic

graphene is asemi-metal orzero-gap semiconductor.

http://en.wikipedia.org/wiki/Allotropehttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Plane_(geometry)http://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Semi-metalhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Semi-metalhttp://en.wikipedia.org/wiki/Semi-metalhttp://en.wikipedia.org/wiki/Semi-metalhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Sp2_bondhttp://en.wikipedia.org/wiki/Plane_(geometry)http://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Allotrope

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Experimental results from transport measurements show thatgraphene has a remarkably high electron mobility at room

temperature, with reported values in excess of15,000 cm2V1s1

http://en.wikipedia.org/wiki/Electron_mobilityhttp://en.wikipedia.org/wiki/Electron_mobility

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The second method is called chemical-vapor deposition, or CVD. Inthis method, a hydrocarbon flows into a heated chamber containing asubstrate coated with a catalyst, such as iron particles.

The temperature in the chamber is high enough to break the bondsbetween the carbon atoms and the hydrogen atoms in the methanemolecules resulting in carbon atoms with no hydrogen atomsattached.

Those carbon atoms attach to the catalyst particles where they bond

to other carbon atoms forming a nanotube. A brand-new method usesa plasma process to produce nanotubesMethane gas, used as the source of carbon, is passed through aplasma torch. Nobody has revealed the details of this process yet,

such as what, if any, catalyst is used.One of the initial claims is that this process is 25 times more efficientat producing nanotubes than the other two methods. The lattice canbe orientated differently, which makes for three different kinds ofnanotubes.

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These tables represent various properties of nanotubes compared toother conventional materials

Above table: Mechanical properties of engineering fibers.

Below table: Transport properties of conductive materials

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Nanotubes in ElectricalWiringA new method for assembling carbon nanotubes has been used to create fibers

hundreds of meters long.

Individual carbon nanotubes are strong, lightweight, and electrically conductive, and

could be valuable as, among other things, electrical transmission wires.

But aligning masses of the nanotubes into well-ordered materials such as fibers hasproven challenging at a scale suitable for manufacturing.

By processing carbon nanotubes in a solution called a superacid, researchers at

Rice University have made long fibers that might be used as lightweight, efficient wires

for the electrical grid or as the basis of structural materials and conductive textiles.

Others have made carbon-nanotube fibers by pulling the tubes from solid hair-likearrays or by spinning them like wool as they emerge from a chemical reactor.The Rice group has used acid processing methods to assemble carbonnanotubes into fibers 50 micrometers thick and hundreds of meters long.

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Application of nanotubes in

electrical wiringThe application of nanotubes in electrical wiring will reduce the losses in electricalenergy to almost zero, while the changing temperature of the wire does not change its

resistance.

Copper-based wires lose about 5 % power for every 100 miles of transmission. Not

only will the energy losses be less, thus increasing the electrical potential of a grid, butit will be sensible for power stations in far-away less populated areas, like deserts, that

power large cities thousads of miles away with little loss.

The mechanical properties of this material will make it less susceptible to faults and

in need of less maintenance.

On a more down-to-earth level, aluminium wire coated with carbon nanotubes is

easier to make and is being used in power transmission.When the temperature of a metallic material rises the electrical resistanceincreases while that of a wire coated with carbon nanotubes does not.Electrical resistance measurements conducted in carbon nanotube coated

cables show a decrease of about 50 % in electrical resistance.

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The application of carbon nanotubes in power transmission canprovide vast improvements to todays means, as in all other fields.Not only will transmission lines be greatly improved, but also theloads will be more efficient and consume less electrical energy.

Appliances will be longer lasting and less faulty prone.Nanotubes are miniscule particles that are not easy to controlnor produce.

There are certain methods that are in use to create them, likehigh-pressure carbon monoxide deposition or chemical-vapor

deposition, yet this is far from enough to satisfy global needs.

For now nanotubes are a dream, but are in the making; andone could argue that a breakthrough might be just around thecorner.

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References1. Nanotechnology for dummies, by R. Booker and E.Boysen, Wiley Publishing Inc., 20052. Nanocyl, carbon nanotubes,http://www.nanocyl.com/CNT-Expertise-Centre/Carbon-

Nanotubes3. PeakOil, exploring hydrocarbon depletion, carbonnanotubes for electrical transmission

http://peakoil.com/forums/post1067733.html4. Technology review, making carbon nanotubes into longfibres, http://www.technologyreview.com/energy/23921/

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QUERIES?

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Thank you