8 ms·
Inside tiny tubes, water turns solid when it should be boiling
- saganus 10y ago“This gives us very stable water wires, at room temperature,” he says. Even the name is cool: "water wires". So beyond fiber optics we could have water wires? This should help photonics researches make a (faster) computer with light, right?
- sho 10y ago> water conducts protons at least 10 times more readily than typical conductive materials Protons, not photons!
- SturgeonsLaw 10y agoIf it increases the rigidity of the nanotube wires it could take us one step closer to a space elevator
- namaemuta 10y agoCould you elaborate, please?
- VLM 10y agoUnfortunately it probably would not. Space elevators are limited in tension not buckling Solid core things are not considerably stronger in buckling than hollow (there is some increase but not staggering huge like orders of magnitude) Also with the exception of giant single crystals, the microstructure usually doesn't relate very closely to macrostructure. The best human scale I beam material does not resemble I beams at microscopic scale, for example the microstructure of steel is very important to its properties but has nothing to do with its behavior in an I beam. The best buckling material, if buckling even mattered which it doesn't, would probably not be microscopically tubular. Space elevators are engineer-annoying in that it requires no basic research and not much engineering work to build a low-G one like on the moon, we have everything we need, yet one for the earth is at least one or two or three fundamental research steps away. Assuming you mean boring passive mostly inherently stable designs. If you want to make launch loops and rotor-vators then all bets are off and if you can handle the dynamic stability problems (and the massive cost) we can make those today. Note I'm talking about the engineering... we have industrial scale capacity to build a lunar elevator with materials that have been proven space rated, in comparison people insist on comparing them to earth elevator designs where at best we have theoretical calculations of theoretical compounds that might be almost good enough if they can be made at all, then made in massive industrial quantities and if they can be space rated. Spectra fishing line is good enough for a toy scale lunar space elevator, technically it would work but you'd get much higher payload with fancier stuff. In my infinite spare time in my retirement or something I'm going to make a small scale launch loop capable of flinging snowballs or model airplanes or similar, or possibly never get around to doing it, or possibly end up a Darwin award winner. I can't even imagine what the FAA would think of a loop that I've calculated is technically within my ability to build and finance. Of course if the wire snapped I'd be in a substantial amount of trouble especially if it finally impacted a foreign country or something. In theory using relatively boring materials a large nation-state level effort could easily replace first and probably second rocket stages with a loop. One interesting solution to the reusable first stage problem is to not have one to begin with.
- barisser 10y ago1nm carbon nanotubes... I doubt these can be produced at macroscopic scale. Moreover the difference between 1.05 and 1.06 nm drastically affected freezing point. I don't think these can be built, en masse, to such precision.
- deleted 10y ago[deleted]
- Rovanion 10y agoPerhaps at this time.
- contravariant 10y agoWell, they wouldn't have to be made with precision provided there's an easy way to separate them. Which is still difficult but could be doable.
- jessriedel 10y ago> Moreover the difference between 1.05 and 1.06 nm drastically affected freezing point. I think the author might have misread something. The Van der Waals radius of a carbon atom is only 0.17 nm, so the radius of a single tube can't vary in steps of 0.01 nm. Maybe this just referred to the average tube radius?
- tgb 10y agoHmm. A tube is composed of many carbon atoms in a ring. Add one more atom, you increase the circumference by 0.34nm but the radius only by 0.34/2pi=0.054nm. So still looks infeasible.
- micaksica 10y ago> “All bets are off when you get really small,” Strano says. “It’s really an unexplored space.” I'm going to assume that this pun was intentional by Strano, and sadly I think it's gone past everyone who's in awe of the actual finding.
- james_a_craig 10y agoI wonder if the forced phase-change the confinement causes applies to other contexts? Could we use a similar trick to force superconductive materials into their low-temperature superconductive phase at higher temperatures? (Repost of the same comment from the other thread about the same paper)
- Retr0spectrum 10y agoThat was my first though too - although my understanding of physics is too poor to know if the two contexts are actually related.
- inlineint 10y agoI'm by no means an expert, and I may be wrong, but I personally don't think that it's possible to achieve superconductivity at room temperature and normal pressure using this approach at the current state of the art. If you take a look at the phase diagram of the water [1] you could notice that the pressure required to crystallize water at temperature near 105°C is something near p_freeze = 2.5⋅10^9 Pa. However, the water is inside of the nanotubes of radius r = 0.5⋅10^(-9) m (the article says about the tubes being of diameter 1.05 nm). Such small radius creates significant surface tension (the same force that allows soap bubbles to exist) which is expressed by equation [2] as Δp = γ/r. According to [3] the surface tension coefficient for water at 105°C is γ = 58⋅10^(-3) N/m, so Δp ≈ 1.2⋅10^8 Pa. The required for crystallization and the actual pressures differ in just one order of magnitude. But the reasoning above used the macroscopic physical laws, and of course one could expect deviations from them when thinking about diameters as small as 4 water molecule diameters. Of course there is still no theoretical model that describes this configuration and calculates exact values of p_freeze and Δp precisely for it. But such model don't have to change the orders of magnitude in the problem, just estimate factors of order of 1, and we could use rough intuition gained previously about the process even without such model. So if you try to apply these intuitions to the superconductivity you immediately meet difficulties because all known superconductors are in solid state, not liquid. It could be overcome by putting it to the nanotubes in liquid state and then letting it crystallize. Let's assume that this is possible. Evidence [4] suggests that to get a superconductor at high temperatures it requires to have pressure of order 10^11-10^12 Pa. This pressure is two orders of magnitude higher than the one required to freeze water at 100°C. That means that surface tension coefficient in such material should be two orders of magnitude higher than in liquid H2O to create pressure of order of magnitude required for phase transition to superconducting state. I wasn't able to find data about surface tension in superconducting materials like like H2S mentioned in [4], but I doubt that it is 100 larger than surface tension in water. And it is impossible to significantly increase pressure by decreasing radius of tubes because this radius is already of order of molecules size. So I don't think that it is possible to get high temperature superconductors at normal pressure and room temperature using nanotubes and already known superconducting materials. [1] https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Phase_diagram_of_water.svg/700px-Phase_diagram_of_water.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Ph... [2] https://en.wikipedia.org/wiki/Surface_tension#Surface_curvature_and_pressure https://en.wikipedia.org/wiki/Surface_tension#Surface_curvat... [3] https://srd.nist.gov/JPCRD/jpcrd231.pdf https://srd.nist.gov/JPCRD/jpcrd231.pdf [4] https://arxiv.org/pdf/1506.08190v1.pdf https://arxiv.org/pdf/1506.08190v1.pdf
- civilian 10y agoI understand that this requires carbon nanotubes, but I'm still excited that we're one step closer to Ice-9
- avian 10y agoReading this reminded me of polywater. https://en.wikipedia.org/wiki/Polywater https://en.wikipedia.org/wiki/Polywater
- mannykannot 10y agoI get the impression that these results are at least thermodynamically plausible, unlike polywater.
- karmacoda 10y agoAs a non-physicist I was thinking the molecules become jammed, immobilised upon expansion; for want of a better analogy a swollen foot in a shoe, no more wiggle room. But the article says that the solid water does melt at even higher temperatures.
- geon 10y agoKind of like this? https://www.youtube.com/watch?v=aI0euMFAWF8 https://www.youtube.com/watch?v=aI0euMFAWF8
- cyberferret 10y agoAlways enamoured of the properties of water - there is still so much to learn. I remember in my flying school days we were learning about microscopic drops of water which, at altitude, would retain their liquid state below 0degC and only freeze when coming into contact with metal or another foreign object. Biggest cause of icing on wings, intakes and carburettors (on piston aircraft). Because the molecules were still in liquid form, radar cannot identify it as an icing hazard... Pretty much the opposite end of the scale from this article.
- FreeFull 10y agoA fun experiment to try is using your freezer to supercool water inside a plastic bottle, and then making it suddenly freeze by smacking the bottle.
- eumoria 10y agoyea just make sure you use distilled water so there's few particles for the ice to form. tap water will just freeze right up
- cr0sh 10y agoWe did something like this in high school as part of our chemistry class. We supercooled the distilled water using a salt/ice bath, taking it well below freezing (in a test tube). Then we introduced a "seed" (don't remember if it was a chip of ice, or a bit of sand, or what) - and watched it "freeze" instantly. I'd have to look at my notes to know what the experiment actually was for, how it was conducted, lab notes, etc - because there was a point to it all (not just as a demonstration of super-cooling and freezing)...
- Declanomous 10y agoThat reminds me of a really cool experiment we did in chemistry. You can create anice packs" that are basically a super-saturated solution that precipitates when you snap a little trigger in the corner of the pouch, creating an endothermic reaction. It was really awesome, and I definitely remember a lot more from experiments like that then I do "titrate [x] in to [y] and take notes" experiments.
- ceejay 10y ago"electrical and thermal properties of ice while remaining stable at room temperature" This sounds pretty amazing. My first thought was there has to be some sort of application toward air conditioning. However, then I started thinking that an even better place to start would be to find ways to utilize this in clean energy. The scale / complexity of production could probably be a non-starter, but (just as an example) if I can put ice into a body of water and more or less guarantee it will never return to water form, at a large enough scale it probably could have hydro-electric applications.
- delinka 10y agoI'm not sure how "non-defrosting water" gets us to "hydro-electric applications." Can you elucidate?
- ceejay 10y agoForgive me if the idea appears somewhat naive. Please correct me if I'm wrong about this but, given that the "frozen" water exhibits thermal properties of ice, in theory couldn't a closed system be built to generate electricity given the constant displacement of water running through the system. By taking advantage of the constant cycle of temperature variations within the system? EDIT: Just looked it up, it appears difference in weight between 4 deg C and 21 deg C (1 ft^3 of water) is a little more than 1/10th of 1 lb. http://water.usgs.gov/edu/density.html http://water.usgs.gov/edu/density.html
- kriztw 10y agoIt sounds like you are proposing a perpetual motion machine, which cannot work because of the laws of thermodynamics (see https://en.wikipedia.org/wiki/Perpetual_motion https://en.wikipedia.org/wiki/Perpetual_motion).
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- haikuginger 10y agoMicrofuidics have a lot of interesting potential applications; $SPOUSE works on using them for point-of-care diagnostics, also in the MIT ChemE department.
- aexaey 10y agoInterestingly, there seem to be an established names for flat/planar/2D inclusions: https://en.wikipedia.org/wiki/Intercalation_(chemistry) https://en.wikipedia.org/wiki/Intercalation_(chemistry) As well as for point/0D inclusions: https://en.wikipedia.org/wiki/Clathrate_compound https://en.wikipedia.org/wiki/Clathrate_compound ..but not for what this article describes, which appear to be linear/1D inclusions.
- kazinator 10y agoAlso: if you confine water to a single H2O molecule, you can make the entire phase phenomenon go away!
- ihaveahadron 10y agoAlso if you arrange them in the shape of a circle they will make a circle of atoms!
- ihaveahadron 10y agoWater is just atoms put together,. The molecules will do whatever humans decide to do with them, those that know how to that is. Oh I mean molecules are beautiful. Throw up. Good looking women are beautiful not a fucking tree or something.
- kafkaesq 10y agoLookout -- they're that much close to discovering ice-nine: https://en.wikipedia.org/wiki/Ice-nine https://en.wikipedia.org/wiki/Ice-nine