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Can you roll these sheets into a tube?
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They would be oriented the wrong way if you did that. The tubes must run parallel to the elevator, not perpandicular, in order to take advantage of the extreme strength.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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WHY?
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*sigh* Here goes...
The CNT sheets from this article are grown perpandicular to the plane of the sheet, so if you were to use this procedure make pipes instead of sheets then the CNTs would be oriented radially pointing away from the center of the pipe.
The "holy grail" CNT material strong enough to support its own weight and more at 24,000 miles can only be achieved by having long CNTs oriented along the axis of force.
This is because the bennefit of CNTs over normal materials is that you can use the high strength of the chemical bonds to transfer force instead of relying on only on the attraction between seperate molecules.
If you make a pipe or elevator cable out of CNTs which are oriented perpandicular to the cable/pipe, then you will only be using the attractive force between seperate tubes, and not the bonding strength. The strength of anisotropic CNTs only works in one direction.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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What if you rolled the square sheet corner to corner?
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Then you'd no longer have a tube.
Graeme
There was a young lady named Bright.
Whose speed was far faster than light;
She set out one day
in a relative way
And returned on the previous night.
--Arthur Buller--
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You can't "roll" the sheets persay at all, because the nanotube sheet edges won't join together after they have grown in length.
I was thinking along the lines of taking the sheet method and wrapping it around a slowly spinning drum during the growth phase to produce a solid tube without having to bond any edge together.
Either way, it would not form the straight perpandicular cable or pipe you could use since the tubes would be radially oriented in either case.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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You can't "roll" the sheets persay at all, because the nanotube sheet edges won't join together after they have grown in length.
I was thinking along the lines of taking the sheet method and wrapping it around a slowly spinning drum during the growth phase to produce a solid tube without having to bond any edge together.
Either way, it would not form the straight perpandicular cable or pipe you could use since the tubes would be radially oriented in either case.
You could wrap strips of it on a 45 degree angle kind of like a cardboard tube. You could probably even correlate a section to provide a mini-truss. You could wrap it in two different directions to keep it from wanting two twists. If you want more longitudinal strength maybe weave some of the 45 degree strips in and out of longitudinal strips. Don’t weave the first two layers though if it is being used for a pipe because for a pipe it is important to have the inside layer as smooth as possible.
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I don't think you are picturing it John, when I say "perpandicular to the plane" I am not kidding, they really do only grow normal to the plane.
Now, if you had been reading the above posts, you would have realized that the CNTs only have their fantastic strength in the direction of the tubes. Only.
So, weaving strips of them doesn't do you one bit of good. You have to transmit the load normal to the plane to access the huge strengths, if you push or pull them from the sides they will just crumble.
There is no huge resistance to twisting either, CNTs are relativly flexible and would break the matrix apart, the only situation where anisotropic CNTs are strong is tensile strength normal to the plane. Period.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I don't think you are picturing it John, when I say "perpandicular to the plane" I am not kidding, they really do only grow normal to the plane.
Now, if you had been reading the above posts, you would have realized that the CNTs only have their fantastic strength in the direction of the tubes. Only.
So, weaving strips of them doesn't do you one bit of good. You have to transmit the load normal to the plane to access the huge strengths, if you push or pull them from the sides they will just crumble.
There is no huge resistance to twisting either, CNTs are relativly flexible and would break the matrix apart, the only situation where anisotropic CNTs are strong is tensile strength normal to the plane. Period.
I was just saying that instead of growing them in a plain grow them in long ribbons with the tubes oriented in the direction along the ribbon. Maybe that isn’t possible in this process. I will read more. Okay I see I misread what you said but couldn’t you perhaps chop up several sheets and press them into a ribbon with the tubes oriented the right way? Or maybe you could apply shear forces to change the alignment of the tube.
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We can't yet grow tubes reliably even a centimeter long yet. The tube must be signifigantly longer to accomplish anything, and may even have to run much of the length of the cable to make it affordable.
Once the tubes are produced, there is no practical way to join tubes together end-to-end with the same structure.
Applying sheer forces would ruin the ordering of the intertube lattice, which will cost you strength particularly with short tube lengths.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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You could be right. Time to get out my calculater.
Do you know any good articles on this. What kind of bonding adgents are there (A.K.A Matrix)?
http://grad.uprm.edu/tesis/cornierrios.pdf]Effect of Recycling on Material Properties of Polyethylene Terephthalate At Various Recycling Ratios and Recycling Generations By Harold Cornier-Rios (PDF)
http://www.google.ca/search?q=cache:2Uc … =en]Effect of Recycling on Material Properties of Polyethylene Terephthalate At Various Recycling Ratios and Recycling Generations By Harold Cornier-Rios (HTML)
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The best option I have heard of so far involves oxidizing the CNTs in order to attach side groups that can be strongly bound to the binding agent, perhaps even covalently and/or to eachother. It wouldn't be as good as contiguous tubes, but it would be an improvement.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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