C60 Fullerene as a Freeze Ray?

[Samson4]

If a c60 fullerene was compressed below 70% of it's volume and accelerated at a target; reaching it before it decompresses, would it lower the temperature of the target on impact? If this was don't with a stream of fullerenes, could it be used like a freeze ray?

 

[DrClaude]

Why would it lower the temperature of the target?

 

[Samson4]

Because it takes a lot of energy to compress it that far. That energy must be accounted for.

 

[CWatters]

Not my field but can you compress c60 fullered? Or does it turn into another form of carbon? Cubic?

 

[Samson4]

"C60 solid is as soft as graphite, but when compressed to less than 70% of its volume it transforms into a superhard form of diamond"

 

[ZapperZ]

"C60 solid is as soft as graphite, but when compressed to less than 70% of its volume it transforms into a superhard form of diamond"

But what does the temperature of the gas have anything to do with the temperature of the target in the end? If the gas particles are at 0.99c towards the target, whether the gas is "hot" or not doesn't affect the impact energy it will have on the target. It is this impact energy that imparts heat onto the target, not the temperature of the impact particles.

Zz.

 

[Samson4]

I'm not talking about firing gas, I'm talking about a compressed solid. The fullerene will most likely penetrate any target; being less than a nanometer in molecular diameter. Upon impact; if it decompresses, won't it absorb a large amount of energy? I remember hearing it takes 330,000 psi to produce such a compression. I am assuming the energy needed to compress the fullerene is much greater than that needed to accelerate it.

 

[Drakkith]

There are several important issues here that I can think of:

1. The fullerenes would almost certainly expand before reaching the target.
2. The expansion of the fullerenes inside the target would probably be akin to a small explosive going off.
3. The speed required to keep issue 1 from happening would be extreme. The amount of fullerenes required to produce a noticeble drop in temperature, if it that's even possible, would probably saw your target in half.
4. Is there even a way to keep a fullerene compressed while you accelerate it up to the required speed? If not, then none of the above issues even matter.

 

[Samson4]

There are several important issues here that I can think of:
3. The speed required to keep issue 1 from happening would be extreme. The amount of fullerenes required to produce a noticeble drop in temperature, if it that's even possible, would probably saw your target in half.
4. Is there even a way to keep a fullerene compressed while you accelerate it up to the required speed? If not, then none of the above issues even matter.

This is what I was looking for. Reasons it wouldn't work out.
3.Taking into consideration volume, pressure and time; there should be relatively high energies involved.

4.I was thinking that the acceleration mechanism and the compression mechanism should be the same step. Maybe using electric forces to repel the molecule under high fields. Or maybe a nano-carbon rail-gun. I know this is like talking about flying cars but I'd like an experienced opinion on the matter.

On another note; if the particles did decompress in flight, they would be too small to receive any heat through convection. Shouldn't they be extremely cold on impact? Possibly so cold that they stay partially compressed?

 

[BillTre]

4. Is there even a way to keep a fullerene compressed while you accelerate it up to the required speed? If not, then none of the above issues even matter.

Not sure about the energies involved (bond strength vs. strength of tendency to a spherical shape), but one might be able to:
Modify the fullerene chemically, such that it has a short chemical bond spanning the inside of the sphere between two opposite points.
This will force the sphere into a red blood cell like shape. If the bond can be broken by something like UV light, it could be sprung into a spherical shape by UV illumination, at some point in its path. Its volume would increase. I guess the assumption is that this would decrease the temperature due to sudden density decrease. The release of the energy to spring out the ball result in energy (heat) too.

 

[jbriggs444]

Because it takes a lot of energy to compress it that far. That energy must be accounted for.

If it takes energy to compress, then it releases energy when it expands. That's not a freeze ray, that's a heat ray.

 

[Samson4]

If it takes energy to compress, then it releases energy when it expands. That's not a freeze ray, that's a heat ray.

The input energy will have to be dissipated. Much like what happens in a can of compressed air. So, maybe the compression and acceleration phase can't be 1 step. Unless ofcourse the compression is slow and the acceleration is abrupt.

 

[Vanadium 50]

I don't see why a liquid helium squirt gun wouldn't work even better than what you propose.

 

[Vanadium 50]

The input energy will have to be dissipated.

Where? If it's in your target, it's what jbrigs444 says - it's a heat ray. If it's in the gun, it's what I proposed - a cold material squirt gun.

 

[Samson4]

Where? If it's in your target, it's what jbrigs444 says - it's a heat ray. If it's in the gun, it's what I proposed - a cold material squirt gun.

Before acceleration. Like squeezing a pea. Long compression followed by sudden acceleration. I don't see how helium would be better.

 

[Drakkith]

Before acceleration. Like squeezing a pea. Long compression followed by sudden acceleration. I don't see how helium would be better.

Liquid helium wouldn't cause the target to explode or require unknown technology to achieve your goals.

 

[BillTre]

Liquid helium might be difficult to handle and keep as a liquid until it reaches its target (unless its in an insulated paint ball!).
Liquid nitrogen might be more feasible.

 

[Charles Kottler]

I might be missing something, but the cooling caused by the expansion of a compressed gas is an effect of heat transfer from the surrounding material, increasing the momentum of each gas molecule. The expansion of compressed fullerene would be more akin to the release of a spring, with the change in volume coming from stored energy within each molecule. The resulting momentum of the expanded fullerene molecule will be the same as when it was compressed, so I would not expect it to be removing energy from the surrounding material. The expansion will however increase the momentum of surrounding material so as stated by jbriggs444 and Vanadium 50 the release of the stored energy will increase the temperature overall.

 

[russ_watters]

The input energy will have to be dissipated. Much like what happens in a can of compressed air.

You are mistaking compressing (and expanding) gasses with compressing solids. They aren't the same thing. When you compress a spring, it doesn't heat up noticeably and when you release it it doesn't cool noticeably. It just absorbs the energy of the compression and then releases it when released.

 

[CWatters]

Not sure I agree with that. How does this square with the rubber band on the lip experiment?

http://scifun.chem.wisc.edu/homeexpts/rubberband.html

 

[anorlunda]

If you compressed a medium, put it in a capsule that maintains the pressure, let the heat dissipate, then burst the capsule and allow the medium to expand and absorb heat from the surroundings, you have a freeze gun. Whether it is an effective freeze gun, depends on the properties of the medium.

I think @russ_watters assertion about solids is overly broad. I see no a priori reason why the medium must be a gas.

The novel part of the OP is that he proposes compressing molecules themselves, thus skipping the solid/liquid/gas issue. I always thought of molecules as incompressible, and never considered comprehensibility. The OP doesn't give any evidence that the fullerene molecule is compressible, but the idea is interesting.

 

[Samson4]

Well this has been interesting. I assumed that because the fullerenes undergo a phase change; they would absorb energy as they reverted back.

 

[Samson4]

The OP doesn't give any evidence that the fullerene molecule is compressible, but the idea is interesting.

Compressing fullerenes below 70% initial volume creates a superhard diamond material. It has been done in the lab.

 

[russ_watters]

If you compressed a medium, put it in a capsule that maintains the pressure, let the heat dissipate, then burst the capsule and allow the medium to expand and absorb heat from the surroundings, you have a freeze gun. Whether it is an effective freeze gun, depends on the properties of the medium.

I think @russ_watters assertion about solids is overly broad. I see no a priori reason why the medium must be a gas.

Can you give an example of a solid that heats when compressed and cools on expansion? And better yet, an equation that describes it?

 

[anorlunda]

Can you give an example of a solid that heats when compressed and cools on expansion? And better yet, an equation that describes it?

@CWatters already gave you an example.

Not sure I agree with that. How does this square with the rubber band on the lip experiment?

http://scifun.chem.wisc.edu/homeexpts/rubberband.html

 

[russ_watters]

Not sure I agree with that. How does this square with the rubber band on the lip experiment?

http://scifun.chem.wisc.edu/homeexpts/rubberband.html

I don't know: it doesn't say what the results are, that I can see, and I don't have a rubber band handy. Can you explain?