MIT Scientists Make a Polyethylene Heatsink 153
arcticstoat calls our attention to MIT research that has produced a version of polyethylene that can conduct heat away from computer chips. Polyethylene is the most widely used plastic. It's not clear how practical this research is for industrial-scale use, involving as it does an atomic-force microscope. The work is detailed in a paper published in Nature Nanotechnology this month. "The new process causes the polymer to conduct heat very efficiently in just one direction, unlike metals, which conduct equally well in all directions. ... The key to the transformation was getting all the polymer molecules to line up the same way, rather than forming a chaotic tangled mass, as they normally do. The team did that by slowly drawing a polyethylene fiber out of a solution, using the finely controllable cantilever of an atomic-force microscope, which they also used to measure the properties of the resulting fiber. This fiber was about 300 times more thermally conductive than normal polyethylene along the direction of the individual fibers, says the team’s leader..."
Plastic heatsinks? (Score:4, Funny)
Plastic heatsinks, just don't get them near heat!
Re:Plastic heatsinks? (Score:5, Funny)
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Another one of you "knock at the door" types, as I was telling another person, they
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Hasnt anyone considered that those "fakes" are actually highly advanced technology from the future that the International Time Police Force wasnt able to stop from leaking into the past?
Think of it this way. If an 18th century intellectual found a microchip, he'd think it a just a weird little black rock. We just think those fakes are a weird little bit of plastic. Now we wait for the futuristic motherboard that will run them. I'll be going through the dumpster behind work in about an hour looking for them
Awesome (Score:2, Funny)
What next, a chocolate teapot?
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Re:Awesome (Score:4, Funny)
Milk or dark?
Why does everything have to be racial for you?! ...oh, I see, I didn't realize that was a profession across the pond. My bad.
...
"by RaceProUK (1137575) [slashdot.org]"
Heat Diode (Score:2)
What they basically built is a heat diode of sorts.
Re:Heat Diode (Score:4, Informative)
No, they did not.
They built a material that allows heat to flow along one axis. It can go either way through it, but only in that one dimension.
Maxwell's Demon (Score:2)
Is it electrically conductive? (Score:3, Insightful)
Generally, plastic is not electrically conductive. Which makes it good for mounting electronics. But it is also not heat conductive. Which makes it near worthless for mounting.
A non-electric conductive, but heat conductive material would be very useful. Especially if it is CHEAP. It could be used to distribute heat in buildings and not just on circuit boards.
Article is wrong. (Score:5, Interesting)
Before anyone asks, the article is clearly wrong in the statement "The new process causes the polymer to conduct heat very efficiently in just one direction...", the heat moves along one dimensions, in 2 directions.
Re:Article is wrong. (Score:5, Informative)
"The new process causes the polymer to conduct heat very efficiently in just one direction,"
I was thinking, wow, is this even possible? If this is true, I think they've just created a material that could behave like a passive air-conditioner, heater, refridgerator, etc., while using NO power, ever. That alone must be breaking some serious laws of thermodynamics..
"One dimension" or "one axis," would have been more appropriate than "one direction."
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Damn straight! And to prove my solidarity...
*whips a cloth off a table* I present my PERPETUAL MOTION MACHINE! Now with plastic cooling for more efficient operation.
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I do that every day.
I invented a great new media center PC! It breaks about 78 US laws and 107 international laws.
In fact watching a movie on it will get you the Death penalty in 6 states!
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Don't get them wrong..SOMETHING is being used up. You know the energy it took to build those fibers? It's being eroded away. Eventually heat flow will return to normal for both sides.
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Yes, I was really intrigued and confused, after reading the line:
"The new process causes the polymer to conduct heat very efficiently in just one direction,"
I was thinking, wow, is this even possible? If this is true, I think they've just created a material that could behave like a passive air-conditioner, heater, refridgerator, etc., while using NO power, ever. That alone must be breaking some serious laws of thermodynamics..
One dimension" or "one axis," would have been more appropriate than "one direction."
While this also seemed the most intriguing part of the post, it doesn't have to violate thermodynamic laws. A ratchet basically does this. So if you could create a ton of tiny ratchets out of polymers you could in theory create something that "conducts" heat in one direction. A diode conducts current in one direction......
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It wouldn't break any laws of thermodynamics. Say it only allows heat transfer from A to B.
If A is warmer than B, energy (heat) will flow from A to B (from warm to cold), decreasing A's temperature while increasing B's. This process decreases energy while increasing entropy, making it perfectly "legal" according to the laws of thermodynamics.
If B is warmer than A, nothing happens, or, perhaps more realistically, the heatsink now acts as a thermal insulator and only allows a very small amount of energy to go
Re:Article is wrong. (Score:4, Informative)
Yes, I was really intrigued and confused, after reading the line: "The new process causes the polymer to conduct heat very efficiently in just one direction,"
You said:
You connect a heat source to the bottom of a water tank, as it heats water on the bottom, the density of water in vicinity decreases and flow upward in one direction.
He was talking about conduction. You're talking about convection.
Re:Article is wrong. (Score:4, Interesting)
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No; you too are wrong. The key missing point is a fiddle. And, possibly, an improbable wager. Then we will know if the material will perform as expected, or if it will run afoul of 'the demon'.
Of Devils and Deamons (Score:2)
No, no, no. Demons are chaotic evil, Devils are lawful evil, totally different things. DnD has taught me that much, at least. There's no indication that any of the demons in the band mentioned in that song were of the variety spoken of by Maxwell!
On the other hand, Maxwell's Demon brings order (law) to chaos. Maybe Maxwell misspoke and was talking about a devil?
*Sits down to think on the subject*
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You connect a heat source to the bottom of a water tank, as it heats water on the bottom, the density of water in vicinity decreases and flow upward in one direction.
Yes because that's also the direction of the heat gradient vector. Put a refrigerator at the bottom, and you'll soon find that the transfer of heat is now reversed.
If heat could only transfer from the bottom of the tank to the top, and if the top of the tank was much hotter than the bottom but heat was not transfered to the bottom, then that w
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Thermal bias != Maxwell's Demon.
The second law does not require that heat flow from hot to cold, only that there is a net increase in heat. Obviously this requires an external energy source, though. And the water example is not a thermal bias, no, but it is a neat case. The water actually DOES transmit heat through a vertical column much faster in an upward direction via convection, than cooling (which is only aided by convection under 4C, which is an infl
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Thermal bias != Maxwell's Demon.
The second law does not require that heat flow from hot to cold, only that there is a net increase in heat.
Good point!
And the water example is not a thermal bias, no, but it is a neat case.
Eh, I guess. Heat moving faster in one direction than the other due to convection isn't very surprising.
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Actually I have to change my stance. There has been a good argument made in this thread that a "thermal diode" wouldn't violate thermodynamics any more than an ideal insulator would (and we assume ideal insulators in models all the time without creating perpetual motion machines).
The real violation is when you have two regions of equal temperature, and you move heat from one to the other without spending more energy than what you're moving, creating a heat differential out of nothing and decreasing entropy
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Lulz can neither be created nor destroyed, but can only be transferred along the meme-flux?
It would explain why old jokes get less funny over time, I guess.
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Very happy to see that this was immediately corrected by this AC comment. Thermodynamics does not allow for heat conductivity in just one direction. If such a material was possible it'll be simple to arrange it in such a manner that entropy spontaneously decreases e.g. having heat conducted one way towards a water reservoir. This accumulated thermal energy could than for instance be used to power a sterling engine making this a second class Perpetuum mobile [wikipedia.org].
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Just for argument's sake, the jury is still out on 'thermal rectification'. The key is just that you can't ignore certain parts of entropy generation that will exist in such a device. Here's an abstract link from a young professor at UC-Riverside, currently getting a DARPA Young Investigator Award.
Solid-State Thermal Rectification With Existing Bulk Materials
http://dx.doi.org/10.1115/1.3089552 [doi.org]
As long as the system results in a net entropy increase, some versions of the theory say its possible.
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Intriguing. Thanks for the link.
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How would this be any different than the little spiny things in the light bulb with one dark side and one shinny/white side using heat difference to spin. You're not generating perpetual motion, you'd be using energy from the environment, it'd just resemble perpetual motion in that you'd wouldn't directly see the energy you'd just see a cold spot and a hot spot.
That said, i don't believe it to be possible, but not on any laws i know.
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The little spiny thingy is a perfectly "normal" heat engine in that it exploits a thermal heat difference that is created by an influx of energy from an external source i.e. the photons that heat up the dark side.
The difference with a ideal uni-directional heat conductor is that it allows to create the heat imbalance out of thin air i.e. without putting in additional energy the entropy of the system is lowered. The wikipedia article that I linked to explains this in a bit more detail:
A perpetual motion mac
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True.
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"Sign" is in fact how I normally hear it in english.
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Hmm, it's not often I make a joke that I myself do not get...
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The magnitude and direction are multiplied together. If the sign is negative, the result is that the direction is negated (opposite): not the same direction anymore.
There are three dimensions in three-dimensional space (by definition), but infinite directions, so it's clear that they cannot be the same thing.
There are infinitely many ways to align those three dimensions. So yes, “dimension” would be correct terminology.
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There are infinitely many ways to align those three dimensions. So yes, “dimension” would be correct terminology.
There are infinitely many *alternative* ways to define three base dimensions, but you can have infinitely many directions within the *same* vector space. Not the same thing.
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There are infinitely many *alternative* ways to define three base dimensions, but you can have infinitely many directions within the *same* vector space.
Both of those are correct, and neither is contradictory to what I said.
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Speaking of both being correct, the notion of a vector's direction can be considered both in the context of the line the vector follows combined with its sign, or separate.
For example if you define your vector in terms of 2d polar coordinates, Theta is your direction, and the magnitude could be positive or negative. It's just usually we define the direction of a vector such that its magnitude is positive.
You can also obviously refer to the sign-independent sense of direction as the dimension since you can
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That’s true; positive/negative movement in one direction would equal forward/backward movement along one axis. However, in some cases, it makes no sense to speak of negative movement, and this is definitely one of those cases. Heat never moves backward: it always moves from hot regions to colder ones. So the assumption that the movement is always positive is a sensible assumption, and saying that the material only allows heat to pass in one direction is clearly the wrong way to describe what it does.
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I will certainly agree that while the phrasing in the summary is correct if interpreted a certain (valid) way, it was a poor choice of words because it gives the wrong impression when interpreted the way that most people, even the scientifically minded, would take it in context.
Also, I think it's quite possible that whoever wrote that copy was not aware of the nuances we're discussing, and that "direction" in the sense they meant it is the one where the statement is simply wrong. :)
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Right, the article isn't talking about a heat diode [technologyreview.com].
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Example North-South is a direction
That is linear movement along one axis / in one dimension. It is not a direction. “Direction” is the way you are headed. You may be able to go forward or backward along that line, but forward and backward are always distinct.
If your direction is north, you’re situated along the north/south axis, but if you have a positive velocity then you’re moving toward the north. If your direction is south, you’re on the same axis, but positive velocity indicates that you’re moving to
Dimension, Not Direction (Score:3, Informative)
I think they mean in one dimension, not direction. The plastic will conduct heat longitudinally a lot better than laterally, but it will conduct heat longitudinally equally well both to and fro. If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
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[...] If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
And the destruction of the Earth! BWAHAHAHAHA!
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If they ever come up with a material that only conducts heat in one direction (a thermal "diode", if you will) then that solves our energy woes.
Well they would have invented a Maxwell demon at the same time.
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And prevent anyone from ever having to endure a warm soft drink. Or hot beverages with the tiniest heat source, given enough time.
Alas, physics.
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It’s called a refrigerator, and it requires energy from an outside source.
that explains the heat sink with the new i7 (Score:4, Funny)
Everybody thought it was plastic, but it was just new technology. Now we just have to wait for an announcement on how to mount those crazy i7's
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Everybody thought it was plastic, but it was just new technology.
Uh Duh. New technology is always plastic, then brushed aluminum, then glass. Rinse and repeat.
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I have a plastic bottle of Pepsi here that says exactly the opposite.
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Woosh!
When Pepsi was new technology it came in glass bottles. Then, they moved to aluminum cans. Now, they're in plastic.
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Is it a crystal polymer? (Score:4, Interesting)
If all polymer molecule strings are all oriented the same, is it a crystal?
This setup may show interesting optical properties as well. It's amazing research really, with processing matter at that atomic scale control. Being able to buildup matter that precisely will reveal all new dreamed uses. I really hope this will go forward as discovering industrial processes of controlling matter buildup arrangement at an atomic scale in mass-production.
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Re:Is it a crystal polymer? (Score:4, Funny)
I don't know if the oriented nature of gel-spun UHMWPE fibers is quite at the same level and provides the same thermal properties as ones made by drawing them out with an AFM cantilever, but they might be "good enough," considering that gel spinning is a scalable industrial production method while cantilever drawing is a "very careful scientist" sort of method.
Well, I have a solution for that. Swap out all the CAPTCHAs on major sites for a webcam peering into an electron microscope that allows a person to draw out the polymer molecules with the cantilever. A week or two, tops, and you'll have someone who's created a bot that can do it perfectly.
Another, similar way is to have Blizzard do the same thing, except using it as a substitute for a CAPTCHA, for every molecule they pull, they get 1 silver piece added to an account of their choice. You'll get the same results, except the bot will speak Chinese.
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Straight from Wikipedia, “A crystal or crystalline solid is a solid material, whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions.”
Aligning the polymer molecules in one dimension is not enough. They would have to be aligned in all three dimensions.
Thermal conductivity (Score:5, Informative)
Since neither the summary nor the article has been kind enough to expand on "300 times more thermally conductive than normal polyethylene", I figured I'd look it up.
Thermal Conductivity of some common Materials: [engineeringtoolbox.com]
Polyethylene HD: 0.42 - 0.51 W/mK
Aluminium: 250W/mK
Copper: 401 W/mK
Best case scenario: 153 W/mK or 61% as conductive as aluminium, 38% as conductive as copper. Not exactly impressive for a heat sink
What about therm interface Re:Thermal conductivity (Score:2)
Even if 61% of aluminum axed conductivity would have some uses, a heat sink need to have good interfaces with the heat source and with air or other transfer medium. this heat sink example is really inaccurate. Considering if expectations are for moving heat from one place to another, with limited scatter dissipation, the most efficient method is by having a mechanically moving medium (liquid coolant).
Re:What about therm interface Re:Thermal conductiv (Score:4, Informative)
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Re:Thermal conductivity (Score:5, Informative)
don't forget the rest, though:
Density:
copper: 8.96g/cm3
aluminum: 2.7 g/cm3
silicon: 2.33 g/cm3
AluminumNitride (high thermal conductivity insulating ceramic, k~160to190W/mK): 3.33g/cm3
LDPE and HDPE: 0.92-0.97 g/cm3.
So, you're getting a factor of 2-10x in weight savings. Tell that to a aerospace designer and he'll make it work. It's also a cheap material (well, feedstock's cheap. and normal PE is cheap, especially relative to copper these days). Who knows how expensive this stuff might be if they can make more than single fibers.
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Also, I imagine the 1D heat conductivity has got to be useful for something. It really sounds more like a solid block of heat pipe than a generic heat sink.
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It would be awesome for moving heat between layers, as it wouldn't heat the surrounding components as much as a metal via.
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Could Help Cheapen Up Spacecraft (Score:5, Interesting)
The single dimension (not direction) transfer mechanism could also be very useful. If you can ensure that heat will move along only a single axis, you have a bit more freedom in placing sensitive components in and around your conduction paths within your spacecraft. All in all, this could be a really useful material, if it can ever be scaled up for use in industrial applications. Here's hoping.
*crosses fingers*
Of course when plastic is exposed to heat... (Score:2, Insightful)
Competitive, but still not better than (Score:2)
This fiber was about 300 times more thermally conductive than normal polyethylene
Since I couldn't find in TFA the ACTUAL measured conductivity, I turned to the internets:
Using data from the first source I found [engineeringtoolbox.com], at its highest, HDPE's thermal conductivity is 0.51 W/mK. So this material's thermal conductivity in that dimension is about 153 W/mK, or about 3/5 that of Al (250 W/mK), 3/8 that of Cu (401 W/mK), and between 1/6 and 1/15 that of diamond (900–2,320 W/mK, according to wikipedia [wikipedia.org].
So all in all, while this is very fascinating research (and I enthusiastically encourage them t
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In it's current state, I'd use it for standard electronics.
Routers, cable modems, etc. Those are encased in plastic already. Making the plastic thermally conductive instead of drilling holes in it for air circulation could be a huge improvement.
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and between 1/6 and 1/15 that of diamond (900–2,320 W/mK)
A very apt comparison since I only use diamond heat sinks for my gaming machines.
Diamond is widely considered to be one of if not the most thermally conductive material available. This comparison was included because for those familiar, it is a handy reference. It was as if, because your arms are too short to touch the ceiling, you believe it doesn't matter how high it is.
On a side note, there actually IS diamond thermal paste available for sale [innovationcooling.com]! Huzzah.
The ability to direct the heat flow can make up for a somewhat lower conductivity for many applications, and can also allow for layouts and applications which wouldn't work with metal heat sinks.
Since the primary issue with metal heat sinks is generally getting the heat wicked off of them, I'd be more apt to consider Finite E
Name? (Score:2, Funny)
Already been done... (Score:2)
May be not as effective, but apparently marginally saleable [cnet.com]. the user experience so far has been terrible but that's the way it is with any new [raymond.cc] technology [com.com].
Now, to make working CPUs out of lead. Solomon's Gold to the rescue!!! Moore's law will be salvaged by modern alchemy!!!
Sure, but... (Score:3, Funny)
Similar to a Niven superconductor (Score:3)
Lovely, another case of life imitates sci-fi. This development reminds me a bit of the superconductors in some of Larry Niven's books (esp. the Ringworld series). In addition to being an electrical superconductor this material was also a thermal superconductor -- and was used as a sort of sci-fi super heatsink on a few occasions. It was mostly represented by ultra-strong threads, and occasionally a woven cloth IIRC.
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AFM is a slow probe (Score:2, Insightful)
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Right, but the key part of the article was heat and stretch. There are other ways that this can be done to a plastic. Ever see fresh noodles be made by hand, by a master noodle chef?
The chef starts with a large amount of dough, and draws it out, "bouncing" it on the work surface covered with flour. He/she then folds and twists it upon itself and repeats the process many times: 1 very thick noodle, 2 thick noodles, 4, 8, 16, 32... you get the idea. 10 folds and twists give 1024 noodles (often it's folded upo
Sounds somewhat like Polaroid film (Score:2)
I'm not too clear on the manufacturing details here. But the material itself sounds a lot like the original Polaroid film (not the photographic kind, the polarizing kind), which is a type of plastic polymer, impregnated with iodine, which has been stretched in one dimension to align the polymer molecules along that dimension. The iodine atoms are able to conduct electrons between themselves, effectively forming "wires" which absorb radiation polarized along the direction of the molecules. I wonder if a bloc
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No, a Peltier device requires input non-heat energy. No laws of thermodynamics violated. It's just a less efficient heat pump (compared to refridgeration).
Re:Can't it degrade over time? (Score:5, Funny)
make it loose its effectiveness??
They include a tiny wrench to tighten it every so often. The first users are suggesting that you should regularly tighten up effectiveness every 400 hours of running.
MIT researchers are currently trying to counteract this self loosening, you may be able to use loctite [henkelna.com]
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I think he meant loose, as in "loose the dogs of war", rather than loosen. It looses its effectiveness on the heat, maybe? And as it loses its effectiveness it can no longer loose its effectiveness.
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That phrase you're looking for is "let loose the dogs of war".
The verb in that quote is "to let loose", not "to loose".
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Either way, both "let" and "loose" are verbs here.
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"To let loose" is the unconjugated verb. Regardless of how you order the words, the verb (and there is only on in that phrase) is "to let loose". This is an example of a compound verb, which, in most cases, is a combination of two other verbs. It's important to note that when a compound verb is used, you cannot consider the verbs to be independent, as additional meaning is given
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http://www.chompchomp.com/terms/compoundverb.htm [chompchomp.com]
http://members.cox.net/lenco1/grammarpractice/verbs/vphrase.htm [cox.net]
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According to dictionary.com, line 22 under "verb" for loose:
22. Chiefly Nautical. to set free from fastening or attachment: to loose a boat from its moorings.
24. to shoot; discharge; let fly: to loose missiles at the invaders.
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Actually, that's a mistranslation from the original Klingon :)
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Plastic degrades over time, especially in a smoker's environment....
Yes, we definitely need to consider this when creating new technology or using it in new ways...
Commander Riker: Data, we need to reverse the polarity of the deflector dish to push away the incoming antimatter nanoparticles, which threaten the ship with destruction!
Data: But Commander, that has never been tried before, and we do not know what will happen when the reverse-polarity charge conduits come in contact with Ensign Tenneson's to