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aostling
12-23-2008, 11:55 PM
I browsed the Stanford University Bookstore for a few hours today. The shelves of ME books merged into the Nanotechnology section. A book on the bottom shelf was titled Microcanonical Thermodynamics. Classical thermo is hard enough. This nano-version was over my head.

Drexler and other pioneers have been writing about nanotechnology for about 25 years. Stanford now has an entire building for housing a nano-technology faculty. I'm not sure what this technology can do for the current global crisis. Quantum computing, synthetic photosynthesis -- technologies not even glimpsed may emerge from all this attention.

Makes me wonder what the bookshelf will look like in another 25 years.

http://i168.photobucket.com/albums/u183/aostling/nanotechnology.jpg

barts
12-24-2008, 12:51 AM
I browsed the Stanford University Bookstore for a few hours today. The shelves of ME books merged into the Nanotechnology section. A book on the bottom shelf was titled Microcanonical Thermodynamics. Classical thermo is hard enough. The nano-version was over my head.

Drexler and other pioneers have been writing about nanotechnology for about 25 years. Stanford now has an entire building for housing a nano-technology faculty. I'm not sure what this technology can do for the current global crisis. Quantum computing, solar cells -- technologies not even glimpsed may emerge from all this attention.

Makes me wonder what the bookshelf will look like in another 25 years.

Well, late last year some some Stanford folks published some work indicating that using nanoscale silicon wires as anodes for lithium-ion batteries may well improve battery capacities ten-fold... and MEMS (micro electromechanical systems, somewhat larger than nanotech) components are already common-place in electronics (TVs) and automotive applications. Nanotech is showing up first in coatings and other materials applications that leverages the unique behavior of mechanically passive nanoscale materials.

The mechanical engineering needed for nanotech is pretty familiar, except that due to the change in scale mass and other forces/properties proportional to volume are much less important than forces proportional to surface area, so resorting to first principles is more reliable than intuition from the macro-scale world.

I have behind me a bookshelf of mechanical engineering texts/handbooks from the last hundred years or so... I've not bought any new ones lately (I now work in the computer science area, and mech. eng. is a hobby), but the march of technology is slower than one might think, since much of it requires changes in the way people think - and the software in people's heads is the hardest of any to change.

Evan
12-24-2008, 05:36 AM
Stick/Slip takes on a new and dominant role at nano scale. Familiar properties essentially do not exist such as inertia and momentum, both linear and angular. Flow, viscosity, hardness, elongation and nearly everything we normally consider as important either vanish or are minor and inconsequential effects.

Gravity may be ignored in most cases. Van de Waals' forces are everything. They fall off at the inverse !seventh! power with intermolecular distance. This means that the notion we have of appropriate clearances for moving parts must be modified to nearly ridiculous extremes. Clearances may need to be a significant fraction of the size of the part. The notion of "contact" is seriously distorted.

Electrostatic effects take over from electromagnetic effects as a means of directing energy to parts. Lubrication becomes a matter of material choice to control electronic interaction between parts.

There are some very successful nanoscale machines on the market. One of the best examples is the Texas Instruments developed Digital Micromirror Device used in video projectors. It was introduced 20 years ago.



The Digital Micromirror Device (DMD) is a binary spatial light modulator developed at Texas Instruments. The DMD consists of an array of movable micromirrors functionally mounted over a CMOS SRAM. Each mirror is independently controllable and is used to modulate reflected light, mapping a pixel of video data to a pixel on display. A DMD mirror is controlled by loading data into the memory cell located below the mirror. The data electrostatically controls the mirror’s tilt angle in a binary fashion, where the mirror states are either +10 degrees (ON) or -10 degrees (OFF). Light reflected by the ON mirrors is then passed through a projection lens and onto a screen.

http://www.eetchina.com/ARTICLES/2006AUG/PDF/131_vproc.pdf?SOURCES=DOWNLOAD

http://metalshopborealis.ca/pics5/tidlp.jpg

aostling
12-24-2008, 11:04 AM
Van de Waals' forces are everything. They fall off at the inverse !seventh! power with intermolecular distance.


Evan,

That really is an astounding exponent. I've often asserted that the 4th power law for thermal radiation is "the highest exponent in Mother Nature," stating this as a challenge for somebody to refute. With a 7th power law, a doubling of the independent variable results in a 128-fold change in the dependent variable!

Allan

Evan
12-24-2008, 11:46 AM
Allan,

Even more significant is the decay of the nucleonic binding force with distance, a component of the strong force. It is thought to diminish at the inverse square of distance multiplied by the half life constrained distance traveled by the mediating particle, the pi meson, or pion.

The graph of the effective range over an intensity range of 20 orders is nearly a vertical line. It is this force that is the strongest of all, 100 times stronger than the electromagnetic force and 10^38 times stronger than gravity.

Rustybolt
12-24-2008, 12:21 PM
I browsed the Stanford University Bookstore for a few hours today. The shelves of ME books merged into the Nanotechnology section. A book on the bottom shelf was titled Microcanonical Thermodynamics. Classical thermo is hard enough. This nano-version was over my head.

Drexler and other pioneers have been writing about nanotechnology for about 25 years. Stanford now has an entire building for housing a nano-technology faculty. I'm not sure what this technology can do for the current global crisis. Quantum computing, synthetic photosynthesis -- technologies not even glimpsed may emerge from all this attention.

Makes me wonder what the bookshelf will look like in another 25 years.

http://i168.photobucket.com/albums/u183/aostling/nanotechnology.jpg


Start investing in companies that do this stuff now. The market is going to become huge in the next ten years.
Same with private space exploration companies.

Fasttrack
12-24-2008, 01:11 PM
Nanotechnology is considered by many physicists to be the next big "thing" - comparable to the computer technology boom in the last 20 years. They expect research funding and developments to increase exponentially for the next 10-20 years in this field. In fact, I'm looking for two different books on the subject for one of my classes next semester. Unfortunantly for me, I don't find nanoscale science to be particularly interesting, although I suspect it is the "cash crop" for physicists. Kind of like lasers were in the late 80's and 90's.

As far as forces go, the nuclear force is very much like the Van der Waals forces; it is a polarization effect due to the different colors of quarks. Much like the charge distribution in molecules (i.e. a dipole moment) there is a color distribution in nucleons. The strong force "feels" color like the electromagnetic force "feels" charge and results in what is called the nuclear force. The interesting thing about the nuclear force is that it maintains the seperation. If you try to squeeze two nucleons closer together, the repulsive force between them grows because the strong force begins to "see" the other colored quarks in the nucleon. At large distances, the nucleon seems to be colorless and the nuclear force drops off very very quickly. Thus, it is only effective in the ~2 fermi range. The potential that we always used to model the nuclear force was the "paris potential", but I believe there are several others that work as well. (Of course, the historical potential is the Yukawa potential)

dockrat
12-24-2008, 02:01 PM
Start investing in companies that do this stuff now. The market is going to become huge in the next ten years.
Same with private space exploration companies.

uh huh :mad: I did that a few years ago with an outfit that was researching treating cancer with nanotechnology. Now I just have a bunch of wallpaper to show for it. :(

http://www.smalltimes.com/articles/article_display.cfm?Section=ARCHI&C=Bio&ARTICLE_ID=267858&p=109