5 ms·
Unexpected Solidlike Fracture in Simple Liquids
https://journals.aps.org/prl/abstract/10.1103/t2vy-32wr https://journals.aps.org/prl/abstract/10.1103/t2vy-32wr
- nycdweller349 3mo agoSomeone tell me the industries that are going to benefit the most from this in the short and long term and what I can expect to see in the next 30 years as a result of this discovery.
- deleted 3mo ago[deleted]
- helpfulclippy 3mo agoThat sounds like a lot of work for someone to go do for a quanta article about something neat a researcher noticed.
- calrt 3mo agoI worry that this sort of request will become the norm in the age of AI where people forget that people aren’t there to serve them.
- autoexec 3mo agoIf it does I'm just going to start doing what AI does and make up bullshit like Calvin's dad. https://i.redd.it/egytd3v20qo81.jpg https://i.redd.it/egytd3v20qo81.jpg
- lostlogin 3mo agoYou made an account to say that?
- gmueckl 3mo agoMaybe it will not have any mmediate application. But guess what? It's still cool! And that can be its very own reward if you let it. Oh, btw: electricity was a novelty toy for several long decades with no major practical applications. But that eventually changed because people kept researching it. And it changed the world.
- JumpCrisscross 3mo agoIt’s a new, generalizable material-science property at STP. Those almost always find practical uses. (Off the top of my head, a material that dissipates tension below a certain rate but fails when it is applied faster than that rate seems to resemble a mechanical breaker. As in not an electrical breaker that works mechanically. But one that decouples when you pull on it super hard. Being able to do that in fluids means one can potentially do that at very tiny scales. More broadly, if simple fluids have a quasi-elastic mode, that has fundamental implications for hydrodynamics. I'd be super curious to know, for example, if anything similar to this occurs in air or water.)
- labbeth 3mo agoMaybe I'm wrong or too naive... but isn't it related to "cavitation"?
- dgoldstein0 3mo agoFrom reading the article, it does sound like that's a top hypothesis. Pulled fast enough, a bubble from cavitation can form and serve as the nucleation site of the crack
- dd8601fn 3mo agoThis looks like silly putty behavior.
- jdlshore 3mo agoOobleck (corn starch and water) will do this too. But presumably they already knew that. The article describes it as being known to happen in “complex fluids,” but that it was news that it happens in “simple fluids.” Presumably silly putty and oobleck are “complex fluids?”
- EA-3167 3mo agoSpecifically they're the subtype of non-Newtonian fluids, and it's also a colloid, and certainly is very elastic.
- animanoir 3mo ago[dead]
- nelox 3mo agoTurns out glass has been known to be a fluid and to fracture for quite some time. [edit: but glass is not a simple fluid.]
- helltone 3mo agoI thought glass was a solid?
- vlovich123 3mo agoNope, lots of fluids that just flow over such a long period they appear solid.
- klustregrif 3mo agoThat’s a misconception. Glass does not flow over time; it is a rigid, amorphous solid. The uneven thickness seen in old cathedral windows is a result of historical manufacturing. Glass was spun into discs that naturally became thicker at the edges, and builders installed the heavier side at the bottom for stability. Physicists calculate that it would take longer than the age of the universe for room-temperature window glass to visibly deform under gravity. Reference: Zanotto, E. D. (1998). "Do cathedral glasses flow?" American Journal of Physics, https://doi.org/10.1119/1.19026 https://doi.org/10.1119/1.19026
- autoexec 3mo ago> That’s a misconception. Glass does not flow over time;...Physicists calculate that it would take longer than the age of the universe for room-temperature window glass to visibly deform under gravity. so then it does flow over time, just not on a scale where it matters to us.
- rsfern 3mo agoBut this is true for lots of solids, not just glass. Consider creep deformation [0] which is deformation mediated by diffusion of defects in solid materials. It’s a big problem in metal turbine blades, it limits the maximum usable temperature to well below the melting point. The physical mechanism would be similar in glass flowing in this way, so I don’t think evidence of glass flowing like this should make us think of it as a liquid instead of an amorphous solid 0: https://en.wikipedia.org/wiki/Creep_(deformation) https://en.wikipedia.org/wiki/Creep_(deformation)
- jzer0cool 3mo agoThis seems more of inertia, Newton's first law. "An object at rest stays at rest,...". What comes to mind say there is some threshold acceleration (e.g. or at extreme, accelerate to c within some short time, t), then essentially you have a body at rest and breaks at the weakest point. Interesting would be seeing this effect with varying viscosity.
- immmmmm 3mo ago> a project in collaboration with the oil and gas company Exxon Mobil I find it a bit dark that, at a time people, crops, forests and biomes are dying due to extreme heat caused by the fossil fuel industry’s reckless behaviour the last 50 years, the said fossil fuel industry funds research on exotic rheology.
- thorncorona 3mo agowell unless you figure out how to replace plastic..
- autoexec 3mo agoWe could replace a large number of plastics right now and be just fine. Society flourished and thrived before we used plastic for everything in our lives. Some people would make less profit though, so of course it's impossible to make those kinds of changes, but we could.
- computomatic 3mo agoWell, the mainstream adoption of plastics following World War II happens to coincide with an unprecedented period of relative global stability known as the “Long Peace.” So there’s at least some version of “thriving” that was, in fact, not previously achieved. Correlation does not imply causation but in this case it’s difficult to disentangle which innovations have lead to the relative global prosperity that has enabled this, and I think plastics are on the shortlist.
- fodkodrasz 3mo agoYou are mistaking plastics for the MAD doctrine, and nuclear weapons.
- ozlikethewizard 3mo agoThe classic US take on global peace, ask the Koreans, Vietnamese, Iraqis, Afghans, etc, how they feel about the long peace? Moreover, pretty sure it was nuclear weapons, not plastic, that stopped the imperial powers from directly attacking one another.
- brador 3mo agoShould be called semi-rigid fluids. They have a structure, it’s just weak and breaks at weak points as you would expect.
- dataflow 3mo agoI must be missing something. If something is a fluid... or at least a liquid... that means it... flows, right? Flow speed isn't infinite, so whenever you pull apart a liquid, you'll see some remnant of the pre-flow state. The thicker the liquid, the slower you need to pull it apart to see that. Is this surprising? Why wouldn't every liquid do this? In what way is this somehow special to some liquids and not others?
- kulahan 3mo agoCavitation can be another “out” for that energy.
- madaxe_again 3mo agoYour intuition is correct, and what you’re describing is cavitation - which the article goes on to mumble about a little. Honestly, I am also struggling to see what the novel result here is. You can snap off a drip of pitch by pulling on it - if you shear it, it will probably just bend - yank on the droplet and it comes off with a satisfying snap. But then again I suppose if you lead a cosseted life, never played with the contents of a shed, and had your first practical experience of actual hands on behaviour of viscous liquids in a lab… you might shout “Eureka”.
- chupasaurus 3mo agoPitch is a viscoelastic polymer while simple fluids are non-elastic, that's the whole point.
- dataflow 3mo agoAnother issue I don't see how to solve is: how do you even gather the data? That is: how do you even know if someone (a) is doing the same job as a graduate of your program would do, (b) actually skipped a program or its equivalent, and (c) is making more than a graduate of your program? All of these are personal and private information. If I apply to a startup tomorrow and get hired without listing my engineering degree on my resume, then are they supposed to add me to some national database of uneducated engineers, list my compensation, and explain that they would've hired a graduate for the same role too? If I apply to another company and list my degree then is that gonna overwrite the database? How the heck would this actually work?
- dataflow 3mo agoSecond comment for a semi-off-topic question: does the state of matter depend on the gravity? Thought-experiment: take any solid, put it in an infinitely strong cup, and crank up gravity. At some point gravity overwhelms the forces holding the substance together and thus the substance ends up breaking apart and.. filling the cup just like a liquid, no? Does everything become liquid-like at sufficiently high gravity? How does one distinguish what's a solid or a liquid when gravity seems to make them behave similarly?
- madaxe_again 3mo agoIt really depends on what’s in your cup at relatively low gs - some things will deform, others will brittle fracture, others yet will just stubbornly sit there, but if you keep on cranking that gravity dial you’ll get degenerate matter, which behaves quite a bit like a liquid.
- Mielin 3mo agohttps://i.pinimg.com/originals/a1/fb/66/a1fb663d7d2942c1988d78c89f39f225.png https://i.pinimg.com/originals/a1/fb/66/a1fb663d7d2942c1988d... If you put a cup of water in a strong enough gravity, lower part of the cup will have higher pressure, and that part will turn to unusual ice types. While top of the cup will remain liquid. Cranking up a gravity will only change the ratio. This is why people use pressure instead of gravity, pressure is what defines the state. Your main point is something like "material becomes weak compared to gravity, conforms to the cup, as if liquid", or "cant have long range structure". But we already have solids that are like that - sand. Sand doesnt resist change to its shape, it just slides in a new position. And yet we still consider sand to be solid. Angle of a pile in particular. Even a neutron star likely has surface level irregularities on a scale of centimiters. While a liquid can flow to submicron level smoothness even in a diy experiment. Material gets stronger as pressure is increased. Unusual crystal structure becomes available. Superconductors and some other weird properties can exist only when crystal structure is compressed. And this tendency continues all the way to degenerate matter, as in neutron stars. Material from inside of a neutron star is likely the strongest a material can be in this universe. So in the end, "solidness" continues to fight back, presenting enough properties to differentiate it from a true liquid, even if it could look somewhat similar, "shallow pile of material", all the way to degenerate matter of neutron stars.