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Researchers Re-Examine Second Law of Thermodynamics
Many readers have written to tell us that researchers are examining the possibility of using Brownian ratchets to help combat the problem of heat dissipation in miniaturized electronics. "Currently, devices are engineered to operate near thermal equilibrium, in accordance with the Second Law of Thermodynamics which states that heat tends to transfer from a hotter unit to a cooler one. However, using the concept of Brownian ratchets, which are systems that convert non-equilibrium energy to do useful work, the researchers hope to allow computers to operate at low power levels, and harness power dissipated by other functions. 'The main quest we have is to see if by departing from near-equilibrium operation, we can perform computation more efficiently,' Ghosh told iTnews. 'We aren't breaking the Second Law — that's not what we are claiming,' he said. 'We are simply re-examining its implications, as much of the established understanding of power dissipation is based on near-equilibrium operation.'"
"Young lady, in this house we obey the laws of thermodynamics!"
Monstar L
I may just be too stupid to follow this, so feel free to slap me down.
The article sucks, obviously, but they repeat the phrase "Brownian Ratchet" incessantly, and I know what those are: a theoretical molecular machine able to extract energy from a heat source that is in thermal equilibrium. Obviously this would be interesting because normally we use heat transfer to generate energy and if there is no excess to transfer one would suppose (based on the second law) that there is no extra energy to be converted to whatever work needs to be done.
But the article and the summary both use the phrase "non-equilibrium" which suggests the existence of heat energy in excess of what is naturally dissipated, which is, gosh, the source of almost all the power that we use, in one form or another.
So either I'm unclear on the concept of a non-equilibrium thermodynamic state, or they don't know what the fuck a Brownian Ratchet is, and are trying to grab a sensationalist headline by making a wild claim that has nothing to do with what they're actually doing (e.g. running the system fans off steam power or something).
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
Tag: weobeythelawsofthermodynamics
maxwell's demon
old, well-tread, philosophically and scientifically fruitless territory here
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
What a crappy article. Subtracting the techno-babble, it sounds like they want to attach a thermocouple or heat engine to their chips, which has already been tried many times and found to be not worth the effort. Maybe they think they have a better method, but I sure couldn't tell from RTFA.
You are correct.
As described by Feynman, a Brownian Ratchetis a theoretical machine that can extract energy form a system in equilibrium. It is a kind of Maxwell's demon.
Feynman explains why such a machine will not work without a potential energy gradient and is in fact a perpetual motion machine.
TFA seems to indicate that they intend to operate from a system not in equilibrium, which is allowed by the Thermodynamics Police. But it isn't very clear from the summary.
Have gnu, will travel.
Subtracting the techno-babble, it sounds like they want to attach a thermocouple or heat engine to their chips...
Almost. Reading between the lines, it appears that they want to attach thermocouples or heat engines *IN* their chips rather then to them. They appear to be talking about the heat in the individual transistors within chips, rather than the entire chip. From the article, it sounded like they were trying to reduce the heat from each individual transistor and use that heat in different ways.
Can it be done? I have no clue. Can 50,000 nano sized thermocouples be more more efficient than 1 small one? Again, no clue.
Great civilizations have lived and died on false theories. Don't mess up mine with a few facts.
One of my friends got her degree in Linke's lab: http://www.uoregon.edu/~linke/res_ratchet.html . She was good at explaining the ratchets, and one of the things always stressed was that they don't work in thermal equilibrium---by definition!. In any case, Linke's website has good explanations.
My prediction: On *nix systems, a brownian ratchet power saving mechanism will be referred to as "Maxwells's Daemon". On NT based systems, it will be referred to as "Maxwell's Service".
To get the questions out of the way, the Brownian ratchet at equilibrium has been shown not to work, exactly as we might expect from the laws of thermodynamics.
But that's not what they're talking about. They are hoping to use a Brownian ratchet at a temperature differential, which is a clever way to extract work from a temperature differential to be sure, but is fully in line with thermodynamics as we understand it today.
The difficulty I have with this is that the problem in electronics is dissipating the heat fast enough to avoid a meltdown. Extracting work from the differential actually slows the heat transfer down (acts as an insulator) and so would make the device run hotter. It is NOT a cooling solution.
Where it could be useful is in low power devices that typically run well under their heat tolerance with a passive heatsink. In that case, the device could be run hotter in exchange for 'recycling' some of the energy they consume to make them even lower power.
1) An object at rest is ALWAYS in the wrong place.
2) An object in motion is ALWAYS headed in the wrong direction.
3) The energy required to alter either state is NEVER enough to make it impossible but is ALWAYS more than you'd care to expend.
I am my own gestalt.
One of my friends got her degree in Linke's lab: http://www.uoregon.edu/~linke/res_ratchet.html .
If the front page at Linke's lab is related to whatever inspired the article: I bet they're trying to make a microscopic fan (with an external power source) as a linear motor, not a perpetual motion machine. They're not trying to scavenge the power from the heat. They're trying to move the hot molecules around.
Such a fan could be in the form of a structure of electrodes on the top of the chip which moves the coolant by creating intermittent sloped potential wells, using the brownian motion from the heat to accomplish part of the motion of the surrounding coolant.
You'd still be providing the energy to move the molecules when you create and then dissipate the potential wells. You make a "traench with a sloped bottom", the molecules fall into it and slide to one end, you raise the bottom of the hole, lifting them, and they scatter, with some of them ending up over the NEXT trench location next time. No free lunch - you provided the energy to move them by lifting them out of the potential well when you demolished it.
I suspect that they are using brownian ratchets for the motors, rather than trying to move the molecules directly, because they found a way to implement the former efficiently.
But I'd like to see how it works and what makes it better than creating a similar array of stepwise-moving potential wells ala charge-coupled devices. More efficient? Fewer drivers? Sloped potential wells easy to make using triangular or other interesting electrode shapes? Larger structures that can be fabricated at current semiconductor feature sizes?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way