52 In a recently revived comment section, someone found this rather fascinating video showing the third second law of thermodynamics being (apparently) broken. Namely, a mixed solution being unmixed by reversing the stirring process. This video is supposed to effectively show why some of the concepts put forth in the “nanothingiee” word are, frankly, silly and no one has been accused of that more than Jim Tour has.
To be sure, no laws of physics were broken in the filming of this. The concept is, of course, not inherently intuitive for people who live in the non-corn syrup based reality. I.E. fluids do not typically behave this way; not because corn syrup is magical, but because it’s not a fluid humans regularly work in. If we were to consider just how viscus corn syrup is and how much like water it isn’t, we may realize that we cannot accuse the two fluids of possessing exactly the same qualities under exactly the same conditions, even though they’re both “fluids”. As such, the design of machines that purport to “propel themselves” across a surface by using what would amount to be “fricative forces” is somewhat silly if taken into the proper context. Really small things do not behave the same way as regular sized things.
The image above, taken from this post and taken from the article referenced therein, is hopefully just a gross misunderstanding of what happens at such levels. Clearly such a device would not slink forward on a surface for the same reason our corn syrup liquid can “unmix” it self. Reciprocating motion works wonders for our world, but does nothing for the nanoworld or, as it seems, the world of corn syrup.
That Jim Tour post, or at least my light handed approach to it, has been bothering me for a while, so I assume I’d just clear it up. While I respect Tour’s right to express and the quantity of his… erm… creativity, that article was appalling and the reviewers should be found and SHOT for allowing that image to be placed anywhere in the vicinity of such a study since it’s either genuinely specious or grossly retarded, depending on your familiarity with nanoshit.
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I always liked that video, have you seen the people running across a pool of corn starch one?
http://www.youtube.com/watch?v=f2XQ97XHjVw
That video ROCKS! Looks like so much fun. If I ever have a chance to do that…
Miscible homogeneous isotropic low viscosity dilute solutions can spontaneously order while remaining one phase, e.g., the Belousov-Zhabotinsky reaction. BFD.
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“Belousov-Zhabotinsky” 2280 hits
What would happen if the initial state was gelled?
very nice. good understanding of physics and chemistry!
Meh. Miscible homogenous isotropic low viscosity dilute solutions which spontaneously order in one phase can be fixed, in every case of import, with a Dean Stark trap. Or do you suppose only EnviroWhiners and women in washrooms travel in packs?
An initial gelled state would have an even lower Reynolds number: zero. Laminar flow be damned. An exploding denominator is met only with quiet enthusiasm by the most guarded of physicists, everyone else would rather watch the numerator explode – that’s where life gets interesting.
You know… I’ve always wondered. How does a Dean Stark trap work?! You distill an azeotrope of benzene and water which is, what? 4% or something water, so the amount of water in the trap never actually changes, it’s always the 4% azeotrope, yet the water somehow “crashes” out and sinks to the bottom. WTF?
Water is evolved from the reaction, usually a condensation.
Hm, i just understood what you were really asking. The true azeotrope percentage is not always 4%, the water comes out because the azeotrope percentage depends on the temperature. At warmer temperatures, more water can be taken up into the benzene, the whole shebang rises, and then it collects in the spigot (at RT) where the azeotrope percentage is a smidge lower, so the xs water crashes out.
The confluence of overwhelming ignorance with overweening arrogance.
An idiot is not half way to being an idiot-savant.
Oh. Burn. I think.
I can take it. I am an idiot after, all, I’m probably the only one here who thinks that Uncle Al’s benzil crystallation idea (to test chirality symmetry violations in the standard model, that is) is actually reasonable, if a bit expensive for the net resulting enlightenment.
Are you suggesting that an azeotrope has different compositions at different temperatures?
That’s beyond retarded. Get out.
While I’m wrong about how a dean-stark trap works, I’m not retarded.
http://en.wikipedia.org/wiki/A.....dependence
No. You’re retarded. I don’t think the pressure at the bottom of a Dean-Stark is any different then the pressure at the top. Unless the trap is several thousand feet tall, of course. But I’ve not seen one of those.
I’m not sure why you think that the azeotrope ratio changes as a result of pressure at a constant temperature but absolutely doesn’t as a result of temperature at a constant pressure.
Taken from the above link:
“If the graph were replotted for a different fixed temperature, then the total vapor pressure at the azeotropic composition will certainly change, but it is also possible that the composition at which the azeotrope occurs will change also.”
NO NO NO. First, you are confusing the ideal gas law with reality. Second, you cannot change the boiling point of an azeotrope. At lower temperatures an azeotrope is no longer an azeotrope but a mixture of fucking liquids. I.E. it’s not volatilized. You CANNOT, by definition of what an azeotrope is, change the composition of an azeotrope by changing the temperature. If you could you would be able to distill an azeotrope to pureness.
Fucking.
Retard.
Same goes for you, noah. Whatever shit you typed doesn’t make any sense anyway.
http://books.google.com/books?.....&hl=en
“However if the same diagram is examined at a different temperature, it can be seen that the azeotropic composition has changed…”
I think the petrochem people know their shit.
The change is always relative to pressure. At sea level you can be assured of two things:
1. your azeotrope has a constant composition
2. you’re an idiot
We already knew 2. See above.
http://www.rsc.org/publishing/.....9470000597
P. 602
“a rise in temperature will cause an increase in the concentration of the component with the higher latent heat of vaporisation in the pure state.
Since W a b is negative for a maximum b. p. azeotrope, the converse conclusions result for this type by similar reasoning.
…the azeotropic composition moves towards that component which has the lower dp*/dT (in the pure state) as temperature decreases. This is equivalent to the statement that the percentage of that component in a binary azeotropic mixture which has the lower value of dp*/dT increases as the pressure decreases, which is the rule arrived at empirically by Merrima”
You don’t have to believe me or the 1947 paper, but I would strongly suggest refraining from calling people “fucking retards” without getting your own shit straight.
the azeotropic composition is the point at which d(E_vap)/d(chi) is zero, i.e. an extremum induced by Raoult’s law deviation. While boiling azeotropes contribute to the etymology, and may seem “definitional”, the liquid-gas equilibirium is attained in non-boiling situations as well. If you set up a chamber with a stirring beaker of ethanol and pump in moist, ethanol-free air, while bleeding off the air to maintain constant pressure, the beaker of ethanol while evaporating will slowly start to absorb water and asymptotically approach a certain water concentration, at which point the rate of ethanol evaporation from the beaker will match the rate of water evaporation from the beaker. My understanding is that is still called an azeotropic composition (I _could_ be wrong, please correct me if I am) in a non-boiling situation, and it will certainly depend on temperature, because the colligative properties of ethanol and water depend on temperature.
Put a beaker of pure ethanol in a bomb/pressure vessel, seal it, and increase the pressure so that no boiling is possible at 200C.
Heat it to 100C, let the vapor/liquid equilibrate. very slowly introduce water vapor into the system without decreasing the partial pressure of ethanol or total pressure (measurably). As soon as the ethanol composition ceases to change, the water introduction is stopped.
this same process is repeated (fresh) at 200C
Are you telling me the ethanol/water composition will be identical at both temps?
Because you’re thinking of a hetereoazeotrope. Which can evaporate both solvents in a fixed ratio whilst unmixed in bulk solution and, upon condensation, again separate into separate phases. Since the reaction of which you speak most likely is a condensation reaction, and you likely produce water beyond what the benzene can absorb, this is your most likely explanation. Otherwise, I suppose, you would just collect the azeotrope in a Dean Stark trap and flush it as it collects.
Just forget about the burrette and tap part. Get an apparatus with a closed off tube and fill it with some drying agent like MgSO4. Now, all those pesky physics questions can be ignored and it’s a lot easier to explain. Condensation reactions on a small scale don’t generate all that much water anyways and two scoops of MgSO4 should be enough.
So, this video shows that absolute zero can be reached in a finite number of processes?
Be nice, he’s a synthetic.
Aye, but that’s not a very good excuse.
There are no excuses – every narrative is deconstructable. The Theory trangresses all boundaries.
I’m not sure you know what a deconstructive reading or explanation of an event entails. You need to read up on your Derrida. Trust me, I would know.
In this case, you would be deconstructing Kyle’s psyche vis a vis his relationship to purely synthetic jocks. I would start like this:
“In every person who believes themselves superior due to a rudimentary knowledge of current physics, is a reflection of a synthetic jock who doesn’t really care and just wants to make the final compound. This reflection is very apparent in Kyle’s word choice and sentence structure. In fact, this very blog breathes forth the very ideal of a synthetic jock. Something that appears to be hidden, but that was always, already there.”
The image above, taken from this post and taken from the article referenced therein, is hopefully just a gross misunderstanding of what happens at such levels.
I’ll just play devil’s advocate here and say it’s a combination of your and Tour’s oversimplification of the system. I’m not talking about the above example specifically- I don’t think it’ll do what they think it does either. They’ll have to prove it. But your entire argument here is based on the idea of movement at low Reynolds number, and you give the corn syrup as an example. That’s fine, but they are on a surface. The energy of attraction between the surface and analyte is not nonzero, and at the nanoscale, tends to be an important consideration.
If the nanocar was floating in a fluid, then, regardless of how it moved, the car would stay put. But there is an attraction between the surface and the wheel, and arguably that energy changes when the overall geometry of the car changes. If there is an energy difference between any of the wheels, upon restoration of configuration the car might “move” to maximize the forces of attraction (or minimize repulsive forces- what if it hits another car?)
This is definitely the case if the car is placed on a surface with an energy gradient- for example, a gold surface with a lateral potential applied to it. And he’s shown nanocars move on such a surface.
Non specific motion in any direction does not matter! It’s been observed, named and confused with real important shit since then. The reason we (people) can swim under water just by kicking is because we push forward far harder and far faster than we do in the reciprocal motion. In syrup and in a nanocar, such motion would result in no movement, obviously, since there is no movement fast enough for us to propel ourselves forward to such a point that a reciprocal motion won’t drag us back to the beginning point. Interaction with a surface in this case is irrelevant, since propulsion is governed by the internal motion of the object, which is just a cis/trans isomerization and the interaction with the surface is only sufficient to hold the object down – it does not provide leverage for the object to move forward or, for that matter, in any other logican direction aside from whatever place random Brownian motion puts it.
I would argue that the use of fullerene wheels may reduce the overall force necessary to push these things around, but that by no means gives them magic powers to suddenly move like a “worm” or any other macroscopic object.
But if Excimer is correct and they’ve seen net movement down a potential gradient, than it is more valid on some levels.
I can’t find the example of motion across a potential, but motion on surfaces due to potential gradients is well-known- see, for example, this classic paper.
Here is the nano lett paper describing motion of nanocars at elevated temperatures on Au. Here’s a video of it.
If it relies on external forces to propel it, it certainly cannot champion itself as a “self propelled” anything, regardless of what that gradient is. If Whitesides had published that Science paper as a “self propelled droplet of water” it would have been rejected simply on the premise that the author was a giant dipshit.
Interaction with a surface in this case is irrelevant, since propulsion is governed by the internal motion of the object
And I’m arguing that it’s not. Motion on a surface is not Brownian motion because there are other forces involved.
Let’s say you were in the middle of vat of corn syrup that went up to your neck. The bottom of the vat is very rough and uneven. If you were to try and swim to the edge, you’d get nowhere. However, if you were able to place your toe against a rough spot (say, a little trench) and push, you’d move. In this example, you have two extra forces working in your favor: gravity keeping you down, and the intertial force between you and the rough surface.
I’m arguing it might be the same on the surface. Brownian motion alone will not cause it to move, but it does have the (significant) surface-analyte interaction with which to propel itself. It’s obvious that not all configurations of the fullerene wheels will contain the same energy of interaction with the surface. This disparity of energies may give it the energy to “move” as it finds another energy minimum.
The fullerene wheels don’t give it a “magical” way to move, no. But it may give the nanocar several energy wells with which to settle itself into, that are small enough that they may interconvert. If the nanoworm were to propel, it would be from the surface-worm interaction and not from brownian motion.
I think you’re missing the point. Even though there may be more “energy wells” or whatever, unless there’s a ratcheting mechanism, the probability of moving forward is equal to the probability of moving backward. There is no obvious ratcheting mechanism in this design. It’s possible that the hv step is just such a step (because it’s irreversible), and to give Tour some benefit of the doubt, it’s also probably true that one direction is slightly more favorable than the other, but from his design, it’s impossible to tell a priori what direction is more favorable, harder yet to actually program it in.
So it’s kind of a useless car.
Stuff like myosin motors work because there are clear and obvious ratcheting steps governed by conformational changes induced by ATP binding, ADP release, and backwards motion is prevented by the irreversible step of ATP hydrolysis.
http://www.youtube.com/watch?v=vJ9ffKeUCvE
Right. In this case, a ratcheting step would be from a potential gradient on the surface. The cars do “move”- whether directional control is possible in this setup was never claimed.
Doesn’t count. This is like putting a glider in the air and saying it’s a “self-propelled flying machine”.
damn, I wish we could edit our posts. Basically, here’s my point. If you’ve got to apply a potential to get it to move where you want it to, then what the hell’s the point of the hv step? For that matter, what’s the point of the whole “car” setup? You could take a glob of junk, put it on a metal, and “move” it using a potential gradient. I can take a blob of DNA and move it across a gel using a potential gradient. Now, if the DNA moved itself, or converted a nondirectional energy source (i.e. light) into a directional energy source (i.e. motion), that would be impressive.
Who ever said it was a self-propelled machine? The cars are not self-propelled, nor has Tour or me ever said they were. They require external stimuli to propagate. On a potential gradient, the motion may be directional. Whether the motion is actually occurring is moot- they’ve shown the things move.
Although to be completely fair, there are things like “boxcars” and “soapboxcars” which are not self-propelled. But when I think of “car”, I think self-propelled. I’ll be willing to bet you do, too.
And I concur with you, if you read my comments in the previous thread, that the interaction with the Au surface is important for Tour’s “nanocars.” In this paper, however, the claim is rather subtly made that the resulting motion is unidirectional and is a result of cis/trans chemistry when, indeed, the cis/trans chemistry is totally unrelated to the motion it may or may not undergo (there is no evidence presented that it even moves across a surface in the paper). I would bet that Tour will see essentially the same motion regardless of the light shined on these things. All he did was make some stupid molecule with a very specious argument that it may have some vague utility, which was rather poorly contrived and vetted through people who are all too familiar with the Sonogashira coupling and little else.
But let us keep in mind, that the research regarding its purported light driven propulsion hasn’t been published, so I may well be wrong.
I mean, I’m not going to be wrong. But I may be… you never know.
You? Wrong? Never. And just in case you are, you’ll never have to eat your words, since you blog under a pseudonym.
The claim of unidirectional motion is never made. It’s not even subtlely hinted upon. If you read that nano lett paper, where they can watch the movement of a nanocar on Au, it’s obvious that they are interested in how these things move on the surface. A change in conformation may lead to a change in “wheel’ spacing on the surface when viewed by STM (oh by the way, you were looking for a point to the fullerene wheels? You can visualize fullerenes and carboranes by STM, and they adsorb reversibly to Au. And, unlike cubanes, they’re easy to deal with synthetically.) I think it’s an interesting idea, in any case- monitoring the movement of loosely bound moities on surfaces that can undergo conformation changes. They don’t claim that the method of propulsion is via cis/trans isomerization alone (but through a combination of thermal and photochemical pathways), but that it might change the way they move on a surface.
You should have stopped at just making fun of the way he portrays his research. If he had portrayed it blandly like I just did, you wouldn’t bat an eye at it. I don’t like the way he portrays his “nanocars” and “nanoworms” etc., either. Underneath all that oversimplification garbage, however, there are some interesting and, dare I say, relevant problems in nanoscience to be solved.
That Org. Lett. paper should never have been published- it contributes nothing to the literature. It’s just a synthesis of some molecule. If they had displayed conformational changes that suggested a different method of propulsion, then it’d be published somewhere else, and would probably make a decent paper.
But why listen to stupid old me? You’ve said all this before. In that first post you made, you commented to someone else:
Then, today, you forgot your own advice and posted this. Well done.
Contradict myself? Hardly. I never said anything about Tour’s complete research portfolio, which is what I was actually defending in your very out-of-context quote. I still find his nanocar interesting and still would defend the bulk of his work. My argument has been focused exclusively on this paper, which you just said shouldn’t have been published, which proves my point in any regard. So, there’s little to argue about, is there? Stop propping straw men up just to be a “devil’s advocate!” He proposed a hypothesis and it is malarkey. The onus is on him to prove his own hypothesis. Why should it be on me? Is that how science works? People make outrageous claims so other more attentive people can prove them wrong? That’s quite the bastardization of the scientific method. So long as the laws of physics remain rather predictable, so will the outcome of the experiment when and if he ever publishes it.
In any regard, to the claim that he never makes a subtle suggestion that this thing will move unidirectionally, I again say bullshit. That this car will work in a way that is even remotely “worm” like is evidence enough that he rather unsubtly suggested it was going to be capable of unidirectional motion by scooting along a surface like any macroscopic object. He’s comparing it to a fucking worm for Christ’s sake. That leaves little ambiguity in how one anticipates it to move. And let’s review worms, shall we:
1. Moves in a unidirectional motion along a surface by contraction and expansion of its body.
2. Eats dirt, shits dirt.
He made no attempt at suggesting his nano car will eat and/or shit dirt. So, for that he’s off the hook (*rimshot*). The very name and the misleading graphic both suggest, oto, that he’s produced a “machine” that will move like a worm when different wavelengths of light are shown upon it when, in reality, it will just do cis/trans isomerizations over a surface of gold and move around randomly like the rest of his shit.
unidirectional movement could be accomplished by introducing asymmetry in the surface (not necessarily a charge gradient, could be something passive), or asymmetry in the ‘car’ itself (the wheels being the most obvious target), or a combination of both. its not trivial, but its not impossible.
Why are you so angry?
Non-specific motion does not always bring you back to the starting point. You will do a random walk, which, to be fair, is equally useless as returning to where you start, although, you will get somewhere.
Third or second??
Making fun of Jim Tour is maybe one of the most enjoyable aspects of having a blog.
A little too easy of a target though.
Which makes it even more fun!