Next Big Future: Cambridge Making Carbon Nanotubes Ribbons at Centimeter Lengths with 9 Gpa Strength, Which is Four Times Stronger than Kevlar
Brock
· 10 months ago
According to The Spaceward Foundation, that's the same strength as a cable produced by Prof. Windle in 2007 (the 2007 paper was released under the name "Dr Krzysztof K.K. Koziol", but Dr. Koziel is on Dr. Windle's team at Cambridge). Those cables were only measured in mm however, so the advance appears to be in length, not strength. At a density of 1 g/cc the specific strength of these new cables is still in the 9-10 MYuri range. That's certainly good but a minimum strength of 30 MYuri would be necessary to build a space elevator (with 40-60 MYuri being preferable).
If they've gotten up to 1 meter and hope to reach 2 meters by April I expect we're close to ribbons of arbitrary length. That's useful, and certainly has non-elevator uses, but it's going to need a (minimum) 3x improvement in strength (per g/cc) to build an elevator.
the taper ratio of 10 GPa g/cc goes to 613. While the taper for 30 Gpa g/cc is 7 (with 20% safety margin). So you need about 80 times more material for the elevator.
10 GPa g/cc [MYuri's] is better than anything else. Higher than M5 fiber, Zylon, Spectra 2000. Carbon nanotube fibers would finally be the best in practice. As the claim states the strongest ribbon ever. You are correct still short of good enough for a practical earth space elevator. But even if reaching theoretical maximums earth space elevators push what is possible with materials. Thus I like space piers and really good orbital skyhooks more which are very useful for lowering the cost of space access and less demanding. Plus some really nice tall towers would be possible.
Properties of diamond Observed tensile strength up to 60 GPa observed and 90-250 GPa in theory. Density 3.5 grams/cc
17-54 MYuri but it is brittle and in other ways unsuitable.
But lunar and Mars space elevators would still be reasonable and economic.
20 GPa g/cc is about 100 taper.( with 2 times safety margin) 20 GPa g/cc with no safety margin is 12 taper. 20 GPA g/cc with 20% safety margin is 20 taper.
RGClark
· 10 months ago
Diamond may soon be available in bulk size quantities:
Artificial diamonds - now available in extra large. 18:11 13 November 2008 by Catherine Brahic. "A team in the US has brought the world one step closer to cheap, mass-produced, perfect diamonds. The improvement also means there is no theoretical limit on the size of diamonds that can be grown in the lab." http://www.newscientist.com/article/dn16036
Diamonds: a dime a dozen A new way to create diamonds could change the world. Shannon Paulus Science and Technology Writer "A team of geophysicists at the Carnegie Institution for Science is perfecting a cheap way to create large diamonds. In his paper, “On the way to mass-scale production of perfect bulk diamonds,” published in Proceedings of the National Academy of Sciences, Alexander Zaitsev stated that the method could cause a technological revolution. 'A profound impact of this innovation on industry (electronics, optics, thermal management, precise cutting), medicine (diamond scalpel surgery), and jewelry (cheap large brilliants) is difficult to overestimate,' he wrote." http://www.mcgilldaily.com/article/6230-diamond...
Diamond is *relatively* brittle. But the new manufacturing method is also able to create diamond of greater fracture toughness as well. Additionally, there are several methods known in materials science to reduce a materials degree of brittleness.
I wrote about the feasibility of kilocarat diamonds.
1. They have not synthesized them to that size yet to my understanding. 2. they had limitations around the size of the machine chamber and other issues. 3. Even if they go to ten of thousands or a million carats. That seems like it will take decades and be quite costly and you end up with a large rock like object. The process does not seem to be adaptable to making diamond tethers. 4. If Robert Freitas, Ralph Merkle and Philip Moriaty succeed with the diamondoid mechanosynthesis then I can see a large scale diamond-like production process. But also large scale graphene and carbon nanotubes.. Also the material has to be diamondoid and not diamond. Diamond can burn.
I think carbon nanotube or graphene based materials will be used for structural construction like space elevators and tethers in the future and not diamond if you had unlimited quantities at affordable cost for all three. There are many other applications for future large scale production diamond.
jeff_davis
· 10 months ago
You wrote:
"...Thus I like space piers and really good orbital skyhooks more which are very useful for lowering the cost of space access and less demanding. Plus some really nice tall towers would be possible."
I googled "space piers" and got nothing. You were joking then, I take it?
: the structure would require at least ten thousand, and more likely 100 thousand, tonnes of near-atomically-perfect buckytubes or other graphite cable in a tapered form on the order of 80 thousand kilometers long. Build a structure 100 kilometers tall and 300 kilometers long. Put a linear induction (or other electromagnetic) motor along the top. An elevator goes straight up 100 kilometers to the starting end. Payloads are then accelerated horizontally into orbit with an acceleration of only 10 G's (which appropriately cushioned humans can stand for the 80 seconds required). This hybrid approach overcomes the drawbacks of both the typical orbital tower schemes (it's less than 1% the height of a skyhook) and electrolaunch ones (air resistance at 100 km is a million times less than at sea level).
Construction details Compared to the skyhook, which is just barely possible with even the theoretical best material properties, a tower 100 km high is easy. Flawless diamond, with a compressive strength of 50 GPa, does not even need a taper at all for a 100 km tower; a 100-km column of diamond weighs 3.5 billion newtons per square meter, but can support 50 billion. Even commercially available polycrystalline synthetic diamond with advertised strengths of 5 GPa would work. [So 10 GPa would make make it easily] Of course in practice columns would be tapered so as not to waste material; and the base of the tower would be broadened to account for transverse forces, such as the jet stream. Only the bottom 15 km (i.e. 15%) of the tower lies in the troposphere and would have to be built taking weather into account.
The electromagnetic accelerator along the top might be fairly heavy. In many designs, coils have iron cores; NASA's Marshall prototype weighs 100 pounds per foot. If we allow a tonne per meter, the total weight of the accelerator is 300 thousand tonnes. For comparison, the cruise ship QE2 is 70 thousand tonnes. However, most the weight is (relatively cheap) iron. Note that this entire weight, if it were concentrated in one place, could be supported by a column of currently available polycrystalline diamond less than 80 centimeters on a side.
nextbigfuture
· 10 months ago
Also skyhook links
Pdf on hypersonic skyhooks and rotovators The 2.5 times better than Spectra 10GPa tubes allow for tether rotovators of 900 to 1800 km lengths that could take cargo from hypersonic planes or rockets going at 8-11 mach.
Thanks for the response. You have a very informative site. I found some of your articles on diamonds using your search function. Here's one where you discussed the new diamond manufacturing method (which is how I like to refer to it):
You should read some the Carnegie Institution teams papers on their methods. They suggest that the growth rate will be increased by increasing the power level, approximately linearly. Their current growth rate is about 150 microns/hour at about 6 kwatt microwave power level. Microwave generators at the megawatt scale exist, for example, for fusion research. This could produce meter size diamonds in a matter of days. Also, it should work to also use just a lot of the smaller generators which together add up to megawatts of power. A very useful aspect of the Carnegie teams methods is that you can grow the diamond on already produced diamond. This may mean that you won't have to combine all the microwave generators into one powerful beam. You could grow small diamonds separately using small generators. Then join the separate diamonds together by using their CVD process between adjacent sides of diamonds placed close together. In regards, to the million dollar "Tether Strength Competition", http://www.spaceward.org/elevator2010-ts , calculate the width of a diamond cable required to lift 1 metric ton, assuming 60 GPa strength of diamond. You'll find the volume required for a 2 meter cable at this width can fit into a cube 1 cm on a side. In other words the centimeter-sized synthetic diamond created by the Carnegie team is already enough to win the million dollar competition! It wouldn't be a trivial matter though fitting this cube into a cable at this thinness (less than a millimeter wide). Perhaps it could be cut by laser in a spiral pattern so that the entire volume gets turned into a ribbon less than a millimeter wide. There is the problem with this method that diamond is stiff (actually it's the stiffest material known.) Conceivable this could still work since for example glass is normally stiff but when produced in the form of micron wide fibers it is quite flexible. Another possibility would be to cut off very many straight segments of the desired width. Then you might be able to combine them by using the Carnegie teams methods to produce a diamond joining interface between the separate segments.
Bob Clark
Jestiron
· 1 month ago
I need to speak with anyone who knows the strengths of carbon nano-tube cables for use in a conceptual idea worthy of your time. I am specifically looking for an explanation in laymans terms (my training is in Architecture) of the tensile strength as well as weight, cost of production on a MASSIVE scale. This is a concept that excites me as it is something novel that addresses a problem that many inventors have been trying to address for many years.
All Comments
If they've gotten up to 1 meter and hope to reach 2 meters by April I expect we're close to ribbons of arbitrary length. That's useful, and certainly has non-elevator uses, but it's going to need a (minimum) 3x improvement in strength (per g/cc) to build an elevator.
the taper ratio of 10 GPa g/cc goes to 613. While the taper for 30 Gpa g/cc is 7 (with 20% safety margin). So you need about 80 times more material for the elevator.
10 GPa g/cc [MYuri's] is better than anything else. Higher than M5 fiber, Zylon, Spectra 2000. Carbon nanotube fibers would finally be the best in practice. As the claim states the strongest ribbon ever. You are correct still short of good enough for a practical earth space elevator. But even if reaching theoretical maximums earth space elevators push what is possible with materials. Thus I like space piers and really good orbital skyhooks more which are very useful for lowering the cost of space access and less demanding. Plus some really nice tall towers would be possible.
Properties of diamond
Observed tensile strength up to 60 GPa observed and 90-250 GPa in theory. Density 3.5 grams/cc
17-54 MYuri but it is brittle and in other ways unsuitable.
But lunar and Mars space elevators would still be reasonable and economic.
Here is a paper that discusses ribbon mass and taper ratios with different strength of material.
20 GPa g/cc is about 100 taper.( with 2 times safety margin)
20 GPa g/cc with no safety margin is 12 taper.
20 GPA g/cc with 20% safety margin is 20 taper.
Artificial diamonds - now available in extra large.
18:11 13 November 2008 by Catherine Brahic.
"A team in the US has brought the world one step closer to cheap, mass-produced, perfect diamonds. The improvement also means there is no theoretical limit on the size of diamonds that can be grown in the lab."
http://www.newscientist.com/article/dn16036
Diamonds: a dime a dozen
A new way to create diamonds could change the world.
Shannon Paulus
Science and Technology Writer
"A team of geophysicists at the Carnegie Institution for Science is perfecting a cheap way to create large diamonds. In his paper, “On the way to mass-scale production of perfect bulk diamonds,” published in Proceedings of the National Academy of Sciences, Alexander Zaitsev stated that the method could cause a technological revolution.
'A profound impact of this innovation on industry (electronics, optics, thermal management, precise cutting), medicine (diamond scalpel surgery), and jewelry (cheap large brilliants) is difficult to overestimate,' he wrote."
http://www.mcgilldaily.com/article/6230-diamond...
Diamond is *relatively* brittle. But the new manufacturing method is also able to create diamond of greater fracture toughness as well. Additionally, there are several methods known in materials science to reduce a materials degree of brittleness.
The new "Age" you discussed here http://nextbigfuture.com/2009/01/understanding-... is coming, but it will be the "Diamond Age".
Bob Clark
1. They have not synthesized them to that size yet to my understanding.
2. they had limitations around the size of the machine chamber and other issues.
3. Even if they go to ten of thousands or a million carats. That seems like it will take decades and be quite costly and you end up with a large rock like object. The process does not seem to be adaptable to making diamond tethers.
4. If Robert Freitas, Ralph Merkle and Philip Moriaty succeed with the diamondoid mechanosynthesis then I can see a large scale diamond-like production process. But also large scale graphene and carbon nanotubes..
Also the material has to be diamondoid and not diamond. Diamond can burn.
I think carbon nanotube or graphene based materials will be used for structural construction like space elevators and tethers in the future and not diamond if you had unlimited quantities at affordable cost for all three. There are many other applications for future large scale production diamond.
"...Thus I like space piers and really good orbital skyhooks more which are very useful for lowering the cost of space access and less demanding. Plus some really nice tall towers would be possible."
I googled "space piers" and got nothing. You were joking then, I take it?
Description of the space pier is here
: the structure would require at least ten thousand, and more likely 100 thousand, tonnes of near-atomically-perfect buckytubes or other graphite cable in a tapered form on the order of 80 thousand kilometers long. Build a structure 100 kilometers tall and 300 kilometers long. Put a linear induction (or other electromagnetic) motor along the top. An elevator goes straight up 100 kilometers to the starting end. Payloads are then accelerated horizontally into orbit with an acceleration of only 10 G's (which appropriately cushioned humans can stand for the 80 seconds required). This hybrid approach overcomes the drawbacks of both the typical orbital tower schemes (it's less than 1% the height of a skyhook) and electrolaunch ones (air resistance at 100 km is a million times less than at sea level).
Construction details
Compared to the skyhook, which is just barely possible with even the theoretical best material properties, a tower 100 km high is easy. Flawless diamond, with a compressive strength of 50 GPa, does not even need a taper at all for a 100 km tower; a 100-km column of diamond weighs 3.5 billion newtons per square meter, but can support 50 billion. Even commercially available polycrystalline synthetic diamond with advertised strengths of 5 GPa would work. [So 10 GPa would make make it easily] Of course in practice columns would be tapered so as not to waste material; and the base of the tower would be broadened to account for transverse forces, such as the jet stream. Only the bottom 15 km (i.e. 15%) of the tower lies in the troposphere and would have to be built taking weather into account.
The electromagnetic accelerator along the top might be fairly heavy. In many designs, coils have iron cores; NASA's Marshall prototype weighs 100 pounds per foot. If we allow a tonne per meter, the total weight of the accelerator is 300 thousand tonnes. For comparison, the cruise ship QE2 is 70 thousand tonnes. However, most the weight is (relatively cheap) iron. Note that this entire weight, if it were concentrated in one place, could be supported by a column of currently available polycrystalline diamond less than 80 centimeters on a side.
Pdf on hypersonic skyhooks and rotovators The 2.5 times better than Spectra 10GPa tubes allow for tether rotovators of 900 to 1800 km lengths that could take cargo from hypersonic planes or rockets going at 8-11 mach.
Nasa study from 2000
October 28, 2008
High Quality Kilocarat Diamonds.
http://nextbigfuture.com/2008/10/high-quality-k...
You should read some the Carnegie Institution teams papers on their methods. They suggest that the growth rate will be increased by increasing the power level, approximately linearly. Their current growth rate is about 150 microns/hour at about 6 kwatt microwave power level. Microwave generators at the megawatt scale exist, for example, for fusion research. This could produce meter size diamonds in a matter of days. Also, it should work to also use just a lot of the smaller generators which together add up to megawatts of power.
A very useful aspect of the Carnegie teams methods is that you can grow the diamond on already produced diamond. This may mean that you won't have to combine all the microwave generators into one powerful beam. You could grow small diamonds separately using small generators. Then join the separate diamonds together by using their CVD process between adjacent sides of diamonds placed close together.
In regards, to the million dollar "Tether Strength Competition", http://www.spaceward.org/elevator2010-ts , calculate the width of a diamond cable required to lift 1 metric ton, assuming 60 GPa strength of diamond. You'll find the volume required for a 2 meter cable at this width can fit into a cube 1 cm on a side. In other words the centimeter-sized synthetic diamond created by the Carnegie team is already enough to win the million dollar competition!
It wouldn't be a trivial matter though fitting this cube into a cable at this thinness (less than a millimeter wide). Perhaps it could be cut by laser in a spiral pattern so that the entire volume gets turned into a ribbon less than a millimeter wide. There is the problem with this method that diamond is stiff (actually it's the stiffest material known.) Conceivable this could still work since for example glass is normally stiff but when produced in the form of micron wide fibers it is quite flexible.
Another possibility would be to cut off very many straight segments of the desired width. Then you might be able to combine them by using the Carnegie teams methods to produce a diamond joining interface between the separate segments.
Bob Clark
I am specifically looking for an explanation in laymans terms (my training is in Architecture) of the tensile strength as well as weight, cost of production on a MASSIVE scale. This is a concept that excites me as it is something novel that addresses a problem that many inventors have been trying to address for many years.
Please contact me at jestiron@gmail.com.
Thank you,
AJ Sadler