Wednesday, March 14, 2012

spontaneous energy focusing in fluids and solids



ucla |A spectacular example is provided by sonoluminescence which is the phenomenon where by sound is channelled into light. In this effect a diffuse uniformly applied sound wave propagating through water can be observed to spontaneously focus its energy by over a factor of one trillion to generate a very short flash of ultraviolet light. A similar effect can be observed in the flow of water through a converging pipe. At flows which achieve velocity variations of about a meter/second bubbles form in the constriction and then emit picosecond bursts of ultraviolet light as they collapse downstream [flow cavitation].
Another example of energy focusing relates to the everday experience of generating a spark upon touching a door-knob after rubbing one's shoes on a carpet. In the laboratory a controlled realization of frictional-electricity is realized by moving glass relative to mercury. A motion of only a millimeter per second leads to the repetitive acceleration of electrons to at least 1% of the speed of light. Furthermore these electrons are emitted in bursts which are again measured in picoseconds.
Turbulence is another well known example of energy focusing. Here the phenomenon is referred to as intermittency. When a fluid is sufficiently agitated so that the effects of nonlinear dynamics overwhelm the damping effects of viscosity the motion becomes turbulent. The turbulence is not uniform being characterized by regions of unexpectedly violent and quiescent motion.
We also believe that the commonplace effect of friction is an example of the concentration of energy density, or stress. Here a pressure that is uniformly applied to a macroscopic body focuses down to tiny junctions where it reaches levels of one million atmospheres.
None of the above problems has been explained nor is there a generic understanding of the tendency of nature to form structures and focus energy off-equilibrium. In some instances models with many input effects have been generated that can parametrize a portion of the existing data, but these models become quite weak when challenged to make a prediction.
Finally it must be emphasized that these unsolved problems in physics are fundamental. Since no-one has yet succeeded to derive fluid mechanics from the first principles of quantum mechanics [or Newton's Laws] these emergent theories are, as my thesis adviser George E. Uhlenbeck was fond of emphasizing, just as fundamental as the reductionist's so-called first principles of physics.

5 comments:

Big Don said...

Only thing missing here was the part about those clever Egyptians having fully understood and solved all this 5000 years ago but the technology was inadvertently somehow lost to antiquity.......

Dale Asberry said...

Donnie full of lulz this morning, caused me to choke on my tea!

CNu said...

lol, I bask in the radiant warmth of his projected preoccupations...,

Dale Asberry said...

See, he's showing promise. I think he was trying to be funny (in a back-handed sort of way)!

Big Don said...

Actually, getting back to more serious stuff, BD's bullshit detector went off yesterday when you suggested the statue symmetry might have been comparable to numerically controlled milling.  And, of course, the video and text were missing anything in the way of actual numbers.  If all they did is superimpose flipped photos, that analysis could easily have a tolerance of like a half an inch or so which is well within non-mathematical crude means.  BD was not about to buy the book to find out what they actually did to support the claims...

So, this morning, BD fired off an inquiry to a company that makes 3-D laser scanners to see if we could get some accuracy and tolerances info on the X Y Z coordinate maps thus obtained on something statue-sized.  That is how you would probably want to do it with meaningful precision on something sitting out in the real world (not in a laboratory).  Land surveyors figure their laser stuff is within .01 feet (not inches) is how they normally show it -- at least an order of magnitude or two worse accuracy than a milling machine.  And then, consider what kind of shape those statue surfaces might be in after a few thousand of years of weathering, more unknown fractional-inch errors introduced...??

Dunno how they do things in Egypt, but if you actually tried to do this in America, you can run into a couple more problems.  Curators of sacred artifacts frequently won't let you even take fotos if your camera has a modern beam rangefinder claiming it can deteriorate the artifact surfaces.  The Smithsonian and other historic sites have such restrictions in some areas.  Then you also gots copyright issues -- art gallerys won't let you take fotos of their displayed stuff, and suspect the Egyptians might not take kindly to you duplicating Ramses with your (now exact laser-obtained) 3D dimensions.....

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