12-11-2009, 09:53 PM
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#11 (permalink)
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Quote:
Originally Posted by Winfield1990
Well in theory they say that the carbon nanotubes will be around 1000 times MORE CONDUCTIVE than copper and aluminum. while being 1/6th less the weight of copper.
Do any of you even think it will happen , if so what do you think the real conductivity factor vs copper will be?
5x maybe? if they even are able to do what they are trying to do , and if so what year do you think this will even happen.
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Where do I start with this thread.
I have worked with carbon nanotubes.
"1000 times MORE CONDUCTIVE than copper and aluminum"
Did you ever think they may have meant thermal conductivity and not electrical conductivity.
If you want to increase electrical conductivity you go for superconductors.
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12-11-2009, 10:08 PM
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#12 (permalink)
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Quote:
Originally Posted by Christ
Carbon Nanotubes are also purportedly stronger than steel in certain configurations, and have been considered as a sort of "space elevator" mechanism, by which objects could be hoisted into space via a machine that would scale a "rope" suspended by a satellite object.
I'll have to find a reference for that, I'm sure.
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Yes, the carbon nanotubes themselves are way stronger than steel.
But, to make the "space elevator", more a thin ribbon than a "rope" they are used in a binding matrix.
Much like glass fibers are used in a polymer matrix for fiber glass.
The weak point is the binding matrix.
At the present time we can not make a macro-scale nanotube that would be composed of only nanotube structured carbon.
Just to widen the discussion carbon isn't the only element to form nanotubes.
Also related check out graphene.
Last edited by Pu241; 12-11-2009 at 10:55 PM..
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12-11-2009, 10:25 PM
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#13 (permalink)
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Quote:
Originally Posted by Christ
Just about all (if not all) conductors have carbon in them. Carbon is conductive. Maybe pure carbon is a better conductor than something else that is part carbon?
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Uh, No!
Electrical conductivity is a the ability of am element or compound to permit the free movement of electrons through it.
Where as a insulator is just the opposite.
What about metal carbides?
They can have high carbon contents, but are insulators.
It is the chemical structure that permits or restricts both electrical and thermal conductivity not the carbon content.
What about metals in general, no carbon there!
What about Magnesium Diborane (MgB2)?
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12-11-2009, 10:54 PM
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#14 (permalink)
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Quote:
Originally Posted by Christ
Ever heard the term "carbon based"? .
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Wow, ever hear of the term crack, as in what are you smoking?
Carbon based means that it structure is based in carbon and its chemical properties. Like "carbon based life", not that non-carbon based life has been found yet.
Quote:
Originally Posted by Christ
I don't directly correlate transfer efficiency to carbon content, but all things in nature can be dated by their carbon content. All things currently known to be in existence (that I'm aware of) are carbon based.
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Uh, once again NO!
Radiocarbon(C14) dating is good for once living material and only back 60,000 years, or so.
Maybe a little further with very sensitive isotope separation via a accelerator.
What do you think coals radiocarbon content is?
Given that it can be over 280 million years old and the half-life of C14 is approx 5,700 years?
There are other radioactive elements used to date things that are inorganic and/or older than the current radiocarbon limit.
Check out U/Pb, K/Ar, or U/Th dating techniques.
How do you think the Earth's age was determined to be 3.8 Billion years old.
So far as I know no living organisms or there remains have been detected from this period, so how did they date the rock via C14?
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12-11-2009, 10:54 PM
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#15 (permalink)
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Moderate your Moderation.
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Quote:
Originally Posted by Pu241
Uh, No!
Electrical conductivity is a the ability of am element or compound to permit the free movement of electrons through it.
Where as a insulator is just the opposite.
What about metal carbides?
They can have high carbon contents, but are insulators.
It is the chemical structure that permits or restricts both electrical and thermal conductivity not the carbon content.
What about metals in general, no carbon there!
What about Magnesium Diborane (MgB2)?
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Next time, please read all the posts in the thread. You can move on after you've realized that not one of those posts was serious.
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Last edited by Christ; 12-11-2009 at 11:04 PM..
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12-11-2009, 11:15 PM
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#16 (permalink)
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Quote:
Originally Posted by Winfield1990
Which is the reason its in the off-topic tech section of the forum , even though it applies to ecomod techonology.
But the topic is about opinions about the technology , so guessing I think is the whole point of this particular thread
I don't like to spread myself around multiple forums either , so I just stick to one forum.
I'm just wondering if this technology even is more hype than reality.
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So you know someone using nanotubes for moding their vehicle for increased FE?
I don't have an issue with the discussion so much as the lack of understanding you have shown for basic science, let alone advanced material science.
I highly recommend you join other forums, just to read and understand the science behind the technology you you seem to think is hyped.
Nano-technology holds many promises, some which we will reap quickly, some of which many never come to fruition.
check these out:
SciCentral: Physics & Chemistry News
PhysOrg.com - Science News, Technology, Physics, Nanotechnology, Space Science, Earth Science, Medicine
And don't be afraid of Wikipedia when you don't understand something.
Guessing about the workings of technology when you have access to the internet is just plain stupid.
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12-11-2009, 11:26 PM
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#17 (permalink)
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Quote:
Originally Posted by Christ
Next time, please read all the posts in the thread. You can move on after you've realized that not one of those posts was serious.
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Oddly enough I did, and I see no evidence that in fact your posts were not serious.
I did seriously debate posting, thinking why should I dissuade you of your notions on how things work.
My concern wasn't for you, but for some one else who may have stumbled across this and taken those notions as facts.
[edit]
Actually, it looks like you did make reference to being a "smartass" this morning, and I read this thread to it's then completion last night.
I started a reply and just didn't have the time to complete it till this evening.
Thank god, my apologies!
Last edited by Pu241; 12-11-2009 at 11:39 PM..
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12-12-2009, 02:43 AM
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#18 (permalink)
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Quote:
Originally Posted by Winfield1990
....
To gather opinions related to the 1000x as electrical conductive as the theoretical limit states , whether that is more hype , error , or actually a close reality of the nanotubes.
All of that aside , Why didnt you go to wiki yourself instead of telling me to , whenever you said to me are you sure that is about the electrical conductivity and not the thermal conductivity for the carbon nanotubes?
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Electrical conductance of a SWNT have had actual measure measurements of electron density of 10EE7 A-cm2 with indications of the ability (theoretical?) to exceed 10EE13 A-cm2(way more than 1,000 times that of Cu).
Thermal conduction(measured at a specific temp, 100 degrees K) approaches nearly 40,000 W/m-K (again, way more than Cu)
These are actual measurements, but are on isolated (sometimes individual tubes) laboratory prepared samples. Production of bulk material with these values is unlikely.
Unless a new fabrication technology is developed, of which there are many under development.
Didn't need to check Wiki, as I know both thermal and electrical conduction of specific type (sub-classes) of these materials have very high conductivity. Typically, high thermal conduction in these materials preclude high electrical conduction and vice versa.
Many times the conductivity of these materials is anisotropic and these values are only seen along the axis of the tube, not across it.
So with the general term "conductive" used and no reference provided how did you know electrical conduction was meant?
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12-12-2009, 01:42 PM
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#19 (permalink)
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Quote:
Originally Posted by Winfield1990
Im just saying it said 1000x more electrical conductive in theory
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I don't see how that could possibly be. If you look at e.g. line losses in electric power transmission over copper wires, they run about 10%, so even a perfect conductor could only improve by that 10%.
Also see here for recent news about nanotubes made from materials other than carbon: Better Nanotubes May Be on the Way -- Fox 2009 (1210): 3 -- ScienceNOW
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12-12-2009, 08:04 PM
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#20 (permalink)
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Quote:
Originally Posted by jamesqf
I don't see how that could possibly be. If you look at e.g. line losses in electric power transmission over copper wires, they run about 10%, so even a perfect conductor could only improve by that 10%.]
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Yeah, fell into the same trap when I first started working with these.
It's the difference between conductance vs conductivity:
Electrical conductance - Wikipedia, the free encyclopedia
Electrical conductivity - Wikipedia, the free encyclopedia
This is the best explanation without all the vector and tensor equations making things more complicated than they need to.
Everyone reports current densities of 1000x Cu, or even higher for carbon nanotubes.
But if conductivity is equal to current density over electric field strength one must assume that the electric field strength in Cu and Carbon nanotubes is the same.
I would have thought with a 1000x higher current density that the electric field strength would be higher and thus would reduce the ratio.
Wouldn't be the first time I was wrong!
Might well rest with those previously mention vector and tensor equations.
One consequence of this is that a cabon nanotube can be 1/1,000, in theory, the cross section (or less) of an equivalent Cu cable carrying the same amount of current.
Quote:
Originally Posted by jamesqf
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Good link!
Also, other on going work have used both "buckyballs" and nanotubes (carbon and other compositions) as cages to hold other elements and compounds.
These materials exhibit such promising characteristics as super-conduction, helium traps, and fission fuel containment and moderation.
Last edited by Pu241; 12-12-2009 at 08:09 PM..
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