Slashdot Mirror
Phase Change in Fluids Simulated
brendotroy writes "After decades of work by the physics and computer science communities, scientists at the University of Rochester have finally created a mathematical model that will allow scientists to simulate and understand phase changes. This discovery 'could have an impact on everything from decaffeinating coffee to improving fuel cell efficiency in automobiles of the future.'"
Decaffinating coffee? Improving fuel economy?
These are not men!
Latewire
Well, sometimes a good cup of coffe is what you want, but if you were to have any now you'd be wide awake for hours.
Sometimes, it's all about fooling the taste buds without affecting brain chemistry.
Lost at C:>. Found at C.
Can it show why lakes don't freeze from the bottom up as water approaches 0 Celsius?
Freezing water is an example of a first order phase transition, involving a transfer of latent heat across a clearly defined phase boundary. Algorithms have been able to deal with those for some time (or so I assume). The big breakthrough here is that these guys figured out how to model a second order phase transition (i.e phase transitions in a supercritical fluid) without incurring infinite CPU time.
Most people are familiar with first order phase transitions (like melting ice or boiling water) but have never seen a second order phase transition. In general first order phase transitions involve a transfer of latent heat, and are noticeably discontinuous- the two phases are easily distinguishable from each other. Second order phase transitions do not involve a latent heat transfer and there is no abrupt discontinuity during the transition, as they occur above the critical temperature and critical pressure, beyond which the liquid and gas phases are indistinguishable.
The article doesn't explain this at all, but the giveaway here is that the reporter talks about the critical point.
"Long before we (the human race) had any idea what gravity was, we could predict the movement of the planets... but no understanding came of this."
What about the understanding that the Earth is not the center of the universe? That's a pretty big development, with philosophical as well as physical ramifications.
Also, we still don't know what gravity is, we just have better mathematical models of it. Ogg the Caveman understood almost as much about gravity itself when he dropped a rock on his foot, as we do now.
My point is that modeling is a very important means of acquiring understanding. This is why children who play with blocks learn about physical relationships, and people who are having office complexes built like to see scale models -- it helps them understand.
To extrapolate to phase changes -- accurate modeling via computer can make possible the kind of experimentation that may result in greater understanding of what happens at the critical slowdown. What happens when we do X? What happens when we do Y and Z? How can a mathematical representation account for these changes?
Tools for better observation often lead to better understanding.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
The funny thing is, the ID people are pointing to the easiest thing for science to prove in regards to a creation, geology and biology. If the ID types were smart, they'd point to all the questions there are with the creation of the Universe, like what the hell happened after the Big Bang, how the hell did something as convoluted as quantum entanglement come to be...and go Clockwork Universe! There is a God!
But no, they want an interactive God and they don't want to learn physics...
About 10 years ago I was taking a CAD/CAM class and the instructor was one of these literal Bible folks, thought the world was 6000 years old and one day he said something about that. So I went home, got a chart of radioactive decay and brought it to class. Next day during a break, I asked him if he believed in the presence of radioactive Radon gas on Earth, he said, "of course I do", I pulled out the chart, said," well Radon comes from the decay of Uranium after around 4.5 billion years, therefore, the Earth is that old." He turned around and never ever mentioned his theories again.
>decaffeinating coffee
If ever there were proof required that humans are intrinsically STUPID animals.
1 Take naturally occuring plant substance
2 Chemically process it to remove one of its main beneficial ingredients.
3 Drink adulterated crud
Bring on the reign of the insects.
None of that is relevant to my point. I am an experimentalist. I make and measure compounds looking for new physics. If I find a compound with an odd spike in specific heat or a superconducting critical temperature 10K above what is expected then my job only begins. Discovery is one thing (great for chemists) but finding out the reason is the job of the physicist.
Finding a program to model something is great.. don't get me wrong. I understand that many times in our past we had ways to model something before we could understand what we were modeling... if fact see my original post. A huge chunk (if not all) physics is modeling. But having a model does not mean that we better understand the physics behind it. That is my point. Not that it's worthless. Not that it should be tossed out. Only that it does nothing for our understanding.