Full Version: A few more questions/clarifications
| QUOTE (Austere Emancipator) |
| I did check the fullerite, ultra-hard fullerite and the ADNR articles, but they are a bitch to find solid information on. Their structures are quite different from SWNTs and MWNTs, and I haven't the slightest clue if it's even possible to create flexible strands out of them like you can out of fullerene tubes. |
Uhm, that would be polymerized fullerites - the wikipedia article mentions them.
| QUOTE (Austere Emancipator) |
| But it seems to me that if all the molecules go through severe deformation when under pressure, then the strength of the whole strand would be compromised. I assume this is basically the same effect as what the "CNTs are not nearly as strong under compression." bit is referring to. |
There's the catch - as the paper stressed, the effective strenght against that kind of strain is not only increasing, but the deformation itself is reversible.
| QUOTE (Austere Emancipator) |
| Now, if you happen to have the whip wrapped around some poor sod's forearm and pull on it hard, the molecules in the whip will be doing some serious buckling while you're exerting a powerful stretching force on it. |
Buckling is something that happens when you take a rod, support it only a both ends, and then apply pressure to the ends.
| QUOTE (Austere Emancipator) |
| The whip will momentarily be "not nearly as" capable of withstanding a tensile force, and *snap* it goes. |
Like I already said - from a molekule POV, the radius of wrapping it around s.o. arm is so large that it is nearly a straight line.
If you pull then, that would be tension mostly, not pressure or sheer.
| QUOTE (Austere Emancipator) |
I was pretty much quoting right out of it: "5. Conclusions Bonding similarities between graphite and C(60) combined with experimental evidence that solid films composed of C(60) clusters maintain many of the molecular properties of the individual clusters suggests that this system may be useful as a solid lubricant or molecular packing material." |
Yeah, that's what I meant - the paper does not really touch our special problem.
It justs says that C60 spheres are chemically very stable and do not glue themselves to surfaces (the 'like graphite' part), and that a bunch of spheres still acts like a single sphere, just multiplied.
Thus, they are interesting to grease things or use them as shock absorbers in large quanties... which, in fact, are very important properties when considering their use as a bearing lubrificant.
| QUOTE (Austere Emancipator) |
| Yes, isn't it amazing how little research there is as to the potential weaponized forms of fullerens. |
As soon as actual wire is made from them, that may change.
Nanites. That's always the answer, no matter what the question is.
When it comes to stuff like laser pistols and Ex-Ex ammo and the concept of AV pistol ammo in SR3, I just kind of turn off my brain and accept the fact that the SR universe runs under a different set of universal constraints.
As for the way-back-question about whether or not you can dikote a monowhip? I figure that monowhips are about as efficient as they're going to get. I'd go so far as to think that the dikoting process might ruin the damn thing as a monowhip with added thickness.
Forget reduced cutting power -- it might not even be able to spool back into the handle.
When it comes to stuff like laser pistols and Ex-Ex ammo and the concept of AV pistol ammo in SR3, I just kind of turn off my brain and accept the fact that the SR universe runs under a different set of universal constraints.
As for the way-back-question about whether or not you can dikote a monowhip? I figure that monowhips are about as efficient as they're going to get. I'd go so far as to think that the dikoting process might ruin the damn thing as a monowhip with added thickness.
Forget reduced cutting power -- it might not even be able to spool back into the handle.
| QUOTE (Rotbart van Dainig) |
| Uhm, that would be polymerized fullerites - the wikipedia article mentions them. |
So we can safely assume that, apart from hardness and strength, the physical properties of fullerite nanotubes are more or less identical to those of buckminsterfullerene NTs?
| QUOTE (Rotbart van Dainig) |
| There's the catch - as the paper stressed, the effective strenght against that kind of strain is not only increasing, but the deformation itself is reversible. |
How can we read the same articles to mean pretty much opposite things? To me it seems to say that, when under pressure, it becomes harder, but its tensile strength is lowered.
| QUOTE (Rotbart van Dainig) |
| Buckling is something that happens when you take a rod, support it only a both ends, and then apply pressure to the ends. |
Then you should only read the part of my post you quoted with the dictionary definitions "to bend, heave, warp, or kink usually under the influence of some external agency" and "to give way" in mind.
| QUOTE (Rotbart van Dainig) |
| Like I already said - from a molekule POV, the radius of wrapping it around s.o. arm is so large that it is nearly a straight line. If you pull then, that would be tension mostly, not pressure or sheer. |
If the whip is cutting into the person's arm, it is clearly applying a pressure against the arm. Hence the arm is applying a pressure against the whip. This means the whip is undergoing compression as you exert the tensile force upon it, reducing its tensile strength. This would lead to the whip to start breaking up, starting with those filaments where the molecules are most deformed. That's how I understood the situation, at least.
| QUOTE (Rotbart van Dainig) |
| It justs says that C60 spheres are chemically very stable and do not glue themselves to surfaces (the 'like graphite' part) [...] |
That may well be the case. I guess it doesn't necessarily say anything about the relative strength of those bonds. I misunderstood the context of that part of the article.
| QUOTE (Rotbart van Dainig) |
| As soon as actual wire is made from them, that may change. |
Don't get your hopes up.
| QUOTE (Dissonance) |
| Nanites. That's always the answer, no matter what the question is. |
That, and nuclear space monkeys.
AFAICT, carbon nanotubes cannot stand the temperatures the canon SR Dikoting process involves, so Dikoting any kind of monofilament product is a no-no. Also, from what I remember of Cray74's explanations of how "Dikote"-like processes work, the Dikote would be quickly shed off of the wire as it's constantly bending and stretching.
| QUOTE (Austere Emancipator) |
| So we can safely assume that, apart from hardness and strength, the physical properties of fullerite nanotubes are more or less identical to those of buckminsterfullerene NTs? |
Well... that's what the paper is about - assuming the qualities of the sphere structre via simulation.
Given the lack of information on polymerized variants, I don't think we can safely assume anything.
| QUOTE (Austere Emancipator) |
| How can we read the same articles to mean pretty much opposite things? To me it seems to say that, when under pressure, it becomes harder, but its tensile strength is lowered. |
Where do you get that from?
| QUOTE (Austere Emancipator) |
| Then you should only read the part of my post you quoted with the dictionary definitions "to bend, heave, warp, or kink usually under the influence of some external agency" and "to give way" in mind. |
Sorry for applying the usual terms of mechanics of material.
| QUOTE (Austere Emancipator) |
| If the whip is cutting into the person's arm, it is clearly applying a pressure against the arm. Hence the arm is applying a pressure against the whip. |
Of course, but that pressure is only a result from increasing tension, as tension is what draws the sling together.
As soon as the deformation and failure of the arm starts, however, tension and thus pressure drop again.
| QUOTE (Austere Emancipator) |
| This means the whip is undergoing compression as you exert the tensile force upon it, reducing its tensile strength. This would lead to the whip to start breaking up, starting with those filaments where the molecules are most deformed. That's how I understood the situation, at least. |
Given a material hard enough to resist enough to make the whip cross that point, sure - materials fail, sooner than later.
The question is - how soon?
If I'm not totally miscalculating, an ideal bundle of nanotubes that would hold the weight of a metric ton is about twenty times as thick as a human hair.
EDIT: Damn, there goes the calculation. Would a human hair be made out idealy bundled nanotubes, it would be able to hold about 50 kilograms - instead of 200 grams.
| QUOTE (Austere Emancipator) |
| Don't get your hopes up. |
Hopes on what? That very thin, very strong wire will be used for malicous intents, too?
| QUOTE (Rotbart van Dainig) |
| Well... that's what the paper is about - assuming the qualities of the sphere structre via simulation. |
Which paper? Nearly all of the research I found is about the physical properties of buckminsterfullerene and nanotubes made of that, and, while stuff like this doesn't mean much to me[/url], it seems like the structure of fullerite nanotubes would be quite different from that of a buckminsterfullerene nanotube.
| QUOTE (Rotbart van Dainig) |
| Where do you get that from? |
Mainly from the Wiki article: "Carbon nanotubes are one of the strongest materials known to man, both in terms of tensile strength and elastic modulus. [...]
CNTs are not nearly as strong under compression."
| QUOTE (Rotbart van Dainig) |
| Of course, but that pressure is only a result from increasing tension, as tension is what draws the sling together. As soon as the deformation and failure of the arm starts, however, tension and thus pressure drop again. |
The pressure on the strand will be lower when it's cutting through the soft tissues (and, as I said before, I don't doubt that such a weapon made out of these materials could do that just fine), but will spike up again when it hits bones, etc. In short, the tougher the material it's used to cut through, the higher the pressure on it, and also the greater the tensile force you are exerting on it -- in these conditions, the actual tensile strength of the strand would be much lower than, say, the ~600N optimal figure for a 100 micron whip.
| QUOTE (Rotbart van Dainig) |
| Hopes on what? That very thin, very strong wire will be used for malicous intents, too? |
That the scientific community will immediately start researching such options when manufacturing long nanotube strands becomes viable. Bullets are cheaper and kill people better.
| QUOTE (Austere Emancipator) |
| Which paper? |
The one you mentioned.
| QUOTE (Austere Emancipator) |
| Nearly all of the research I found is about the physical properties of buckminsterfullerene and nanotubes made of that, and, while stuff like this doesn't mean much to me, it seems like the structure of fullerite nanotubes would be quite different from that of a buckminsterfullerene nanotube. |
True, P-SWNT'sare not SWNT's.
| QUOTE (Austere Emancipator) |
| Mainly from the Wiki article: "Carbon nanotubes are one of the strongest materials known to man, both in terms of tensile strength and elastic modulus. [...] CNTs are not nearly as strong under compression." |
That does not necessarily mean that there is a sudden drop in allowed tension if pressure is applied:
The article states that they behave different under tension than pressure, which is quite normal.
| QUOTE (Austere Emancipator) |
| In short, the tougher the material it's used to cut through, the higher the pressure on it, and also the greater the tensile force you are exerting on it -- in these conditions, the actual tensile strength of the strand would be much lower than, say, the ~600N optimal figure for a 100 micron whip. |
It's the 'much lower' part that I'm not quite green with.
| QUOTE (Austere Emancipator) |
| That the scientific community will immediately start researching such options when manufacturing long nanotube strands becomes viable. |
Given how chaotic resarch usually is...
| QUOTE (Rotbart van Dainig) |
| The one you mentioned. |
The paper mentions "solid films" of C(60) clusters, but it doesn't seem like they're referring to fullerite. I haven't seen similar experimental evidence for fullerite -- not that I've looked for it much -- so I don't know how applicable that is.
| QUOTE (Rotbart van Dainig) |
| It's the 'much lower' part that I'm not quite green with. |
I just read "not nearly as" as being more or less synonymous with "much lower than". Maybe that's just because I'm a non-native English speaker.
| QUOTE (Rotbart van Dainig) |
| Given how chaotic resarch usually is... |
Maybe if there happens to be a rich cyberpunk-fanboy with the means to do such a thing. Perhaps I'm just overly optimistic about the scientific community, but I can't understand why anyone else would research something so pointless and lacking in any sort of real marketability.
| QUOTE (Austere Emancipator) |
| The paper mentions "solid films" of C(60) clusters, but it doesn't seem like they're referring to fullerite. I haven't seen similar experimental evidence for fullerite -- not that I've looked for it much -- so I don't know how applicable that is. |
C60 clusters are spheres, the solid films the paper is talking about are the sheets graphite is composed of.
| QUOTE (Austere Emancipator) |
| I just read "not nearly as" as being more or less synonymous with "much lower than". Maybe that's just because I'm a non-native English speaker. |
Put simply, nanotubes are stronger if you pull than if you push - if you care to find out what that means, take a rope.
It does not, however, mean that if you push a rope while pulling it, it suddenly snaps.
| QUOTE (Austere Emancipator) |
| Maybe if there happens to be a rich cyberpunk-fanboy with the means to do such a thing. Perhaps I'm just overly optimistic about the scientific community, but I can't understand why anyone else would research something so pointless and lacking in any sort of real marketability. |
It would be a quite boring world if any research conducted would aim at marketability.
| QUOTE (Rotbart van Dainig) |
| C60 clusters are spheres, the solid films the paper is talking about are the sheets graphite is composed of. |
I'm still just quoting the actual article, where it says: "solid films composed of C(60) clusters". I realize that the actual test model they used for that research only had single buckminsterfullerene molecules between graphite layers, that part of the Conclusions refers to what they say right in the second paragraph of the Introduction about recent studies of C(60) solids.
| QUOTE (Rotbart van Dainig) |
| Put simply, nanotubes are stronger if you pull than if you push - if you care to find out what that means, take a rope. It does not, however, mean that if you push a rope while pulling it, it suddenly snaps. |
So what you're saying is that the "under compression" in the Wiki article does not refer to pressure perpendicular to the length of a CNT, but is just talking about a CNT's compressive strength as opposed to its tensile strength? Okay. Then I guess we're back to square one with that.
| QUOTE (Rotbart van Dainig) |
| It would be a quite boring world if any research conducted would aim at marketability. |
Want to give me some other reason for the scientific community going into a monowhip frenzy?
| QUOTE (Austere Emancipator) |
| I'm still just quoting the actual article, where it says: "solid films composed of C(60) clusters". |
Ah, solid as oposed to liquid.
| QUOTE (Austere Emancipator) |
| So what you're saying is that the "under compression" in the Wiki article does not refer to pressure perpendicular to the length of a CNT, but is just talking about a CNT's compressive strength as opposed to its tensile strength? |
Exactly, yet the behaviour concerning shear is missing.
| QUOTE (Austere Emancipator) |
| Want to give me some other reason for the scientific community going into a monowhip frenzy? |
Care to take a more neutral approach on your questions?
It's a bit hard to understand that you are so disturbed by the fact that some things are only researched because someone thinks they might be interesting.
| QUOTE (Rotbart van Dainig) |
| It's a bit hard to understand that you are so disturbed by the fact that some things are only researched because someone thinks they might be interesting. |
Oh, I'm not disturbed by that at all. But, seriously speaking, with all these marvelous potential applications for CNTs, how much time and effort do you think is going to be wasted on something as relatively useless as weaponized monowire? Once the groundwork has been laid for such research, when all they really need to do is get their hands on some CNTs, put a weight on one end and go crazy, some folks will no doubt see what they can do with it -- and it's probably gonna go about as far as "DREAD". But to actually make groundbreaking new research just for the sake of making really painful silly string?
| QUOTE (Austere Emancipator) |
| Once the groundwork has been laid for such research, when all they really need to do is get their hands on some CNTs, put a weight on one end and go crazy, some folks will no doubt see what they can do with it |
Thanks, that's what I said some posts ago.
I guess we've been going back and forth with this too long for me to start arguing about that.
why? because the military does far too much of the worlds research funding andthey will want to know if they can make weapons out of it
| QUOTE (TonkaTuff @ Apr 14 2006, 07:03 PM) |
| Right, it's a singular, homogenous polymer strand. So's fishing line. |
And a car tire, by the way.
Y'all really need to stop getting in a tizzy over monowhips. It's just science fiction in a game; if it made perfect sense it'd be called science fact and it'd be in production.
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