Earlier quoted context omitted.
The writer can not imagine any realistic application for the foreseeable future. But hey, nothing is impossible.
... lots of things are impossible?
Not when fishing for grants.
Scientists report asymmetry between heating and cooling
41–50 of 139 posts
Re: Scientists report asymmetry between heating and cooling
#42While deployed, soldiers I know noticed hot water freezes faster than cold water. The Mpemba Effect, was later proven under some conditions (1)
1. https://www.smithsonianmag.com/smart-news/new-experiment-sho...
Re: Scientists report asymmetry between heating and cooling
#43> While no immediate practical applications exist, the researchers envision enhanced efficiency in micromotors, microscale cargo transport, and materials that can self-assemble or self-repair. Everyone who has ever written a grant application will recognise this wording.
Meh, if self-assembling, self-repairing materials forming a swarm of nano bots was going to take over the world it would have already happened elsewhere in the universe and proliferated everywhere by now. instead we have biology. The actual dominate force in our dimension that did proliferate.
How do you know it hasn't and isn't slowly making its way here? Universe is a big ol' boy.
Re: Scientists report asymmetry between heating and cooling
#44>And have questions like: 'Why don't we have a device like a microwave oven for fast cooling?'" Isn't that... just a blast chiller? (AKA a convection oven in reverse) It's not commonly found in households, but that's different from saying "we don't have a device" that does this. EDIT: Yes folks, I do understand how the principles of operation differ. Point being that the humble countertop convection oven definitely q…
Microwaves penetrate the interior of objects (outside of metal) that are in their Faraday cages, leading the internal temperature of those objects to rise dramatically. Blast chillers work like reverse ovens, from the surface to the interior.
Microwaves target the resonant frequency of intermolecular hydrogen bonds and impart vibration. It's a very special mechanism that doesn't really lend itself to this sort of analogy.
Re: Scientists report asymmetry between heating and cooling
#45Re: Scientists report asymmetry between heating and cooling
#46Also, water that is heated reaches cooler temperatures faster: https://en.wikipedia.org/wiki/Mpemba_effect
Maybe not all that clear-cut?
"While the actual occurrence of the Mpemba effect is disputed"
Re: Scientists report asymmetry between heating and cooling
#47Earlier quoted context omitted.
Would you care to share for those of us who haven’t written a grant application before?
It’s the biggest stretch possible without it being technically dishonest. Everyone knows it: the researchers know it and gag a little as they write it, and the grant reviewers know it but pretty much require it without really ever saying that they require it (competitive landscape and all).
What else can you say when it gets to subject matter like this?
In experimental thermodynamic bench experiments, those who are familiar with boiling water in a common scientific vessel such as a tea kettle, are often familiar with how a system has its own characteristic rate of cooling, depending on the energy of the heated media to dissipate into whatever heat exchange facility is available at the time, usually ambient convection.
Under careful observation it can be seen that often it is possible to impart energy from an external source at a faster rate than the same amount of energy will later require to completely dissipate afterward.
People shouldn't be discouraged whether this is obvious or not.
Experimentation such as this can require quite a bit of dedication, especially among those who are not tea drinkers, but this is the workaround that would be required to arrive at such valid conclusions without the use of equations nor those pesky optical tweezers which are such a pain in the butt.
Re: Scientists report asymmetry between heating and cooling
#48> While no immediate practical applications exist, the researchers envision enhanced efficiency in micromotors, microscale cargo transport, and materials that can self-assemble or self-repair. Everyone who has ever written a grant application will recognise this wording.
Do you mean this general sort of speculative wording or these specific applications? If so, why these applications and not others?
Re: Scientists report asymmetry between heating and cooling
#49I always feel a little stupid or strange reading a lot of these science headlines and introductions. I wasn't aware that people considered there to be a symmetry between heating and cooling. I thought that the entire point of thermodynamics is that they are asymmetric. Even the article mentions that it's been known that heating is more efficient than cooling.
I think the human mind tries to impose order or symmetry on things. Like, "if time can move forward, it should be able to move backwards" I kind of think of explosions and entropy. I just don't see there being an equivalent reverse phenomenon. Even shooting a bullet into icewater or something colder seems like it would cool off many orders of magnitude slower. maybe I'm wrong.
A lot of our experiences are with symmetrical physical phenomenon. So, we're modeled that way.
Time does not "move." Yet we need to conceptualize it. So our language here gets sloppy. You can recognize this by using the modified "if time can move forward, it should be able to be stopped." The obvious incongruity of this defies the idea that we're attempting to impose ourselves.
In terms of Entropy, the universe does not _want_ to be hot, it _wants_ to be cold and empty. So, the finding is genuinely counterintuitive.
Re: Scientists report asymmetry between heating and cooling
#50I always feel a little stupid or strange reading a lot of these science headlines and introductions. I wasn't aware that people considered there to be a symmetry between heating and cooling. I thought that the entire point of thermodynamics is that they are asymmetric. Even the article mentions that it's been known that heating is more efficient than cooling.
I think the human mind tries to impose order or symmetry on things. Like, "if time can move forward, it should be able to move backwards" I kind of think of explosions and entropy. I just don't see there being an equivalent reverse phenomenon. Even shooting a bullet into icewater or something colder seems like it would cool off many orders of magnitude slower. maybe I'm wrong.
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