Physicists Build Circuit That Generates Clean, Limitless Power from Graphene
news.uark.edu
news.uark.edu
Sounds like nonsense to me but the article is so badly written that it's hard to tell. In fact it is hard to be sure whether they have actually created a prototype or merely simulated it.
If you want reporting that accurately represent science, in my experience, the university press releases are even worse than the worst mainstream shit-tier media.
I wonder if universities understand that they're sometimes harming their own people with these things.
AFAICT the administration did not turn a blind eye to Epstein, and in fact barred him. And the scandal is that Joi knew that he was persona non grata and therefore took steps to hide Epstein's funding. That is unquestionably terrible but in my mind doesn't tar the Institute.
I'm certainly not defending (or criticizing) MIT as an institute (there are bigger problems than the dreadful press releases from the publicity office). But if my understanding is correct, Epstein, while lurid, might not be a useful line of attack.
It's as if Google's parking valets were found to be running a car theft ring (made up example): unless Google seemed to think it below their notice, I would have a hard time considering that should be grounds for condemning Google.
I'm not defending MIT (or conflating car theft with sexual abuse) I'm merely saying that if you want to attack MIT consider something more substantive like its slow progress in recruiting and retaining female scientists; it's intimate ties with the government and military (despite various fig leaves assembled over the decades), or its treatment of undergraduates which at best is neglect. Don't waste your efforts on a small, if noisy, lab that has produced negligible research of consequence.
Probably have to read the journal paper to get accurate details.
So what remains is a prestige, attention metric of the university.
> At room temperature, micron-sized sheets of freestanding graphene are in constant motion, even in the presence of an applied bias voltage. We quantify the out-of-plane movement by collecting the displacement current using a nearby small-area metal electrode and present an Ito-Langevin model for the motion coupled to a circuit containing diodes. Numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero. However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath. The exact power formula is similar to Nyquist's noise power formula, except that the rate of change of diode resistance significantly boosts the output power, and the movement of the graphene shifts the power spectrum to lower frequencies. We have calculated the equilibrium average of the power by asymptotic and numerical methods. Excellent agreement is found between experiment and theory.
[1] https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
As the "thermal bath" is supplying power, this seems consistent with it being a Carnot-equivalent heat engine.
There is certainly nothing in physics that prevents the extraction of energy from an environment in which the temperature fluctuates - devices that do so to keep mechanical clocks running indefinitely have been around for some time.
If we take the press release at face value, in this device there is no difference of temperature. So if the Second Law of Thermodynamics is correct it is not possible to extract some useful energy to do something interesting, like turning on the lamp in the animation.
Basically, there are always local micro gradients even though the macro integration of those gradients gives 0. It may as well happen that graphene being few atoms thick and thus dipping into the local scale properties may bridge and aggregate without [total] mutual cancellation those properties into the macro scale (graphehe sheet vibrations may happen be [one of] such a filter, kind of piezoelectric effect). There is no violation of the 2nd law as extracted work/energy wouldn't be larger than the entropy increase resulting from the smoothing of the micro gradients (bringing the Universe's heat death closer).
Or even imagine a pond with no visible movement of water and place over it a myriad of very very small water mill wheels - they will be rotating chaotically back and forward due to small perturbances in the water (and the smaller a giving wheel the larger share of local gradient it will be extracting as the smaller share of it will be mutually cancelling with the neighboring gradients under the wheel). That chaotic rotation of that myriad of wheels can be aggregated into usable work/energy.
The above quote is from the abstract, and just before it, we see the much more reasonable "numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero."
It make sense, but the problem is more subtle. It's better compare the clock with a brick.
In the example of the clock there is a temperature difference that can be used to extract "useful" energy. You can use it to move the clock, or make a sound or light or something.
(I'm saying "useful" as in the a quote of the main author of the paper "What we did was reroute the current in the circuit and transform it into something useful.” .)
If you put a brick in a oven and keep it at the same temperature for some time, until the temperature, humidity and other properties have stabilized, you reach thermal equilibrium. It doesn't mean that the heat energy in the brick is perfectly constant, it exchanges heat with the oven. The heat energy has small random variations.
But unlike in the clock scenario, you can't use this additional accumulated energy for something "useful". To check if it is in a high or a low, you need a variant od the Maxwell's Demon. You can measure the energy exchange and analyze the theoretical and experimental properties anyway.
(Also, if you put the clock in the oven at a constant temperature for a long enough time, it will stop working.)
Stealing the name from a sibling thread, to make the grapheme device produce "useful" energy, you probably need a Maxwell's Diode.
What is 'the problem' that you are apparently trying to address here? Everyone in the discussion is well aware that the 2nd. law of thermodynamics prevents the continuous extraction of work from ambient heat without there being a temperature difference. Are you saying that the paper is claiming that this has been done? If not that, are you claiming that the device, as described in the paper, is incapable of generating power from fluctuations in the ambient temperature? Have you identified some other problem in the paper? Alternatively - I don't think you are saying this, but I will put it in for completeness - could it be that you are saying that the paper shows that this team really has invented a Maxwell's diode, capable of continuously extracting work from the ambient heat of a closed system in thermal equilibrium?
If you are still only taking issue with the press release, you are just nerdsplaining to a bunch of people who already get it, thank you very much.
Probably not, but it is good to know that you are.
The paper is not about a device that harvest energy from the thermal variations of the environment. There is no mention of macroscopic thermal variations in the press release or in the abstract of the paper. Also, the graphene is inside a ultra high vacuum chamber, that is a weird place to put a device that that depends on the macroscopic thermal variations of the environment.
From the abstract:
> However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath.
My interpretation is that the resistor is dissipating some power (from the graphics ~1pW), but it is also absorbing the same amount of power due to the 2nd law. It is not a Carnot engine that produces work from heat.
Are you taking the quoted passage as implying it is performing 100% conversion? This would indeed be a problem, as there is no heat sink at 0K here. That quote, however, is ambiguous, as it says power supplied by the heat bath and not lost from it, and may merely be a statement that it obeys the conservation of energy (i.e. the point being made here may be that the power being supplied to the load comes from the heat bath, as opposed to coming from another possible source, such as the bias voltage supply.)
I really should buy and read the paper, but I am not that motivated yet.
A real engine transform heat into electric energy that can be used to dissipate heat inside a container at any temperature. In particular at a higher temperature that the graphene and the support and the circuit. In the PR they claim that it produce "something useful" that I interpret as "work" or "electrical energy", but in that case it breaks the Second Law even if in their setup the resistor is at the same temperature.
After reading the paragraph again, I'm not sure if your interpretation is right and they are claiming that the device is transferring energy from the graphene to the resistor, but that breaks the second law, in spite in the PR they claim it doesn't.
I think they never claim a 100% conversion anyway. They just don't have a temperature difference to operate the engine.
Another way of thinking about it is that random noise although uniform at large scale, is intrinsically noisy when you zoom in.
I don't remember something like the clock at the molecular level, but I think it is "theoretically possible" (or to be more accurate, "not theoretically impossible").
[Weird example warning]
In the mitochondria the ATP synthase https://en.wikipedia.org/wiki/ATP_synthase use the H+ difference of the inner and outer part to produce ATP. The main problem is how to create this difference without sugar or pyruvate, using only a change of temperature.
Perhaps it is possible to put a weak acid outside of a mitochondria, and select the weak acid that changes the dissociation constant a lot with the temperature.
So when temperature is high it is mostly dissociated and the acidity is high and the mitochondria produces ATP. But after some time there is no difference in the concentration of H+ inside and outside of the mitochondria and the process stop.
Then reduce the temperature so the acidity outside is low, and the H+ inside the mitochondria can escape by other pores. (Perhaps we need to make some additional pores for this? The pores must be small and not very polar.) After some time, the concentration of H+ inside the mitochondria is low again. And we can repeat the cycle.
[/Weird example warning]
This will be painfully slow and painfully inefficient. My biochemistry level is too low to be sure this is possible, but at lest I think it is not theoretically impossible.
It is a small system, so I think it is a relevant comparison in spite it is very different of a graphene membrane in a vacuum chamber.
More detail in this video clip with UArk's Paul Thibado:
https://www.youtube.com/watch?v=wrleMqm3HiU
I think what this research opens up is the possibility of "optimal" harvesting. There is some resonant frequency, some circuit configuration yet to be discovered that is perhaps self-sustaining. They've chosen "stochastic thermodynamical" circuits because its low hanging fruit. But it seems really exciting to me. Almost like a third class of energy production after solar and hydrogen (where 99% of research funds are allocated). Ocean wave energy harvesting perhaps?
In any case, congrats to the researchers on their painstaking hard work ;)
Fluctuation-induced current from freestanding graphene: toward nanoscale energy harvesting
This can only work if there is a temperature difference between the grapheme membrane and the load resistor (the lamp in the animations). Other wise, it breaks the Second Law of Thermodynamics.
The problem is not that it breaks some remark from Feynman, the problem is that if there is no temperature difference, it breaks the Second Law of Thermodynamics and in particular an example in an explanation of Feynman.
> Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.
I’m not a physicist or even an educated layman, can you explain your comment more?
I prefer another quote
> What we did was reroute the current in the circuit and transform it into something useful.
Let's suppose that they get some "useful" energy to turn on the lamp like in the animation or power a small device.
Let's suppose that you use it to power a laser and send a beam that heat some object far away. As a side effect, you are extracting energy from the device with the graphene in the lab so it will get cooler.
So the net effect is that the device in the lab gets cooler and the object far away get hotter. So you have a flux of heat. But if the other object is hotter, you have a lux of heat from in the wrong direction, that is impossible according to the Second Law.
There are a million ways to rewrite this https://en.wikipedia.org/wiki/Second_law_of_thermodynamics in more abstract or more concrete ways. With some oversimplifications, another is that you need at least two heat baths and the efficiency of the device to transform heat from the "hot" bath to of "useful" energy can be calculate using the temperatures of the baths. When the difference of temperature is zero, the efficiency is zero and the device can produce no "useful" energy. Or in other words, with only one heath bath, you can produce no "useful" energy.
I don't think your hypothesis would necessarily break the Second Law. Wouldn't the hotter distant object result in making Brownian motion around it? The same Brownian motion which would eventually end up as energy input at the graphene membrane - provided a thermodynamically closed system?
As so I'm not convinced this study breaks the Second Law, nor do I see how it produces useful work. To me it only seems so, because the system isn't being modeled as a closed system...
EDIT: Actually, I'm pretty sure the following statement is completely false:
>the graphene and circuit are at the same temperature and heat does not flow between the two.
I'd suspect heat does flow between the two, it's just outside their modeling of the system.
Turning heat into usable energy without temperature differential is still an extraordinary claim that demands extraordinary evidence, but I wouldn't dismiss it out of hand
(edit, this is explicitly addressed further in the article: That's an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. "This means that the second law of thermodynamics is not violated, nor is there any need to argue that 'Maxwell's Demon' is separating hot and cold electrons," Thibado said.)
So it sounds like, if this really works, it may have some impact on our general understanding of thermodynamics or the properties of Brownian motion?
My guess is that there is a temperature difference between the grapheme and the resistor. In that case it's a normal experiment, perhaps with some tweak, but not a groundbreaking experiment. The power generated by the device is tiny (not "unlimited"), and there are a lot of similar devices.
Sometimes the experiment is interesting in some niche (this experiment is related to tunnel microscopy) but this is totally overhyped.
There are too many PR announcements like that in the nanotechnology and battery areas. It's either Nobel Prize material or nothing, and you can't tell from the article.
No power numbers. Are they talking about generating a picowatt or something like that?
Somebody like EVworld should publish "1, 5 and 10 years ago today in energy announcements".
> No power numbers. Are they talking about generating a picowatt or something like that?
The figures in the research article claims ~1pW. I still can't get the research paper, but reading the information that is available, and some enlightening discussions in HN I guess they measured a ~1pW exchange of heat in the other side of the device (the "lamp" in the animation). But it is ~1pW in one direction and exactly the same amount in the other direction. There is no net energy flux or "useful" energy.
This may be an useful experimental result in the research branch they are working, but not "Limitless Power".
So why would there be a charge in the flappy capacitor? Well, a bias voltage is applied by this battery in the circuit. Ahem, before invoking any principles of thermodynamics, I'd like to see some detailed measurements, or even careful theory, of the current out of the battery and back into the battery, particularly w.r.t. the instantaneous voltages (P = VI), to prove that the time-average power delivered by the battery is precisely zero, or at least far lower than that putatively transferred to the load (light bulb in the animation). Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.
There is some precedent for semiconductor thermal magic in the Peltier junction. It makes one end colder and the other end hotter by applying electric watts to it, with no moving parts aside from the electrons and holes recombining, or something. But nobody sees thermodynamics being violated or extended there.
But here the magic is to take away thermal energy from one place, the flappy graphene (thereby cooling it) and moving the energy to the light bulb (thereby heating it). It seems you could then use any old heat engine to extract work by letting the heat flow from the resulting hotter place back to the colder place, getting "limitless power" for free from your perpetual motion machine. Conceivably it's a sort of heat pump that gets some multiplier above the battery power. But I think the burden of proof is on the Arkansas folks to explain how this can be. If I had more energy (no pun intended, really) right now I'd try to find the paper that the press release is based on, to see if there's a little more truth there.
Meanwhile, I doubt it.
It's like a nano Rube Goldberg!
Paper is here btw: https://arxiv.org/abs/2002.09947
So, they built a full-wave rectifier (albeit with only 2 instead of, say, 4 diodes)? Pretty neat to see electrical engineering fundamentals at work.
(also, for any who wanted specifics: article is at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0... ; abstract contains a couple of circuit diagrams)
edit: updated link, thanks for pointing that out
Working link for the lazy:
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
But in all seriousness, it seems this converts ambient heat (not a heat differential) directly into electricity. Therefore it must necessarily cool its surroundings by the equivalent energy extracted?
So it’s a kind of air conditioner which doesn’t use electricity to move heat but rather converts heat directly to electricity? I thought we “knew” this was impossible...
Based on this I understood that it'd indeed cool down and create a heat gradient if it wasn't doing any work, but the difference it'd create is instead used to induce a current, which means it probably wouldn't cool down as long as that potential is used in this way instead (?)
I definitely don't know enough about this subject to judge the plausibility of the claim but "graphene" and "limitless power" in the same headline does trigger a few red flags.
Could also use geothermal heat I guess
I'm rooting around for alternative sources of the paper without success, but for those who have read it, what kind of graphene did they use (monolayer, CVD, GO, rGO, etc.)? I suspect that will somewhat throttle the manufacturing supply chain.
Batteries are the least interesting application to me. This brings "sensor dust" out of solid fantasy into the realm of possibility in the far future; at first it will be "sensor clods", but let it follow the same evolutionary Shockley-to-ARM development path, and let's see where it goes. Permanently implanted medical chips to measure the blood, nervous and other internal medicine metrics we want to get our hands on might be more miniaturized; need to figure out how to extract out the incredibly weak signal.
Presumably, those jiggles are always going to be there, unless somehow earth becomes a cold, dead place.
So imagine the solar panel on your calculator didn't need light, just a temperature above absolute zero.
1) The press release is wrong
2) The research article is wrong
3) The Second Law of thermodynamics is wrong.
[As a fast explanation, if the grapheme membrane and the lamp in the animation are at the same temperature, then the electrons in the lamp will get an equivalent amount of random jiggles and will counter the effect described in the article. (There may be also a similar problem with the diodes, capacitor, etc.)]
I might be completely wrong here, but I don't see that much of a difference, antennas are also "harvesting" power in some ways.
It smells like there's actually some interesting research being done here using graphene to extract energy from the ambient environment (possibly harvesting the work done as the graphene expands during hearing?) but the press release was written by someone who does not understand the subject at all.