Also, it reminds me of David Brin's "Earth", where in the near future drug laws have been near-universally made obsolete by the ability of anyone to get high using biofeedback techniques.
I used to TA for a physics course and one of the labs was about sound waves. We used empty plastic tubes and generated sound of a given frequency into them, then the students would change the length of the resonant cavity and find where the standing waves formed, and calculate the speed of sound from this. Then, the final part of the lab was to take the speakers and generate slightly different frequency tones and listen for the beat frequency. I guess this lab is now illegal in Oklahoma!
Oh yeah, just remembered another weird aspect of this story. He would be asked to give a "presentation", which consisted of slides that were prepared by his employers. He'd speak in English and have it "translated" as he went. Of course he had no clue what the presentation was supposed to be about, so he'd basically just babble nonsense for the duration.
I had a couple of friends go live in China for a couple of years. She was teaching english, he did that but also picked up some other "jobs", one of which involved, as far as he could tell, being shipped around to various places in China, dressed up in a suit, and having drinks poured down his throat until he couldn't walk anymore. Near as he could figure, he was supposed to be playing the role of the representative of a foreign company which was working with the Chinese outfit which had hired him, since that would make them look good to possible business partners. Sounds like a pretty surreal situation.
I've been thinking about getting a von Karman vortex street tattoo for years now. Maybe like one of those tribal patterns some people get around their upper arms. But cooler. Main thing that keeps me away is that getting my first tiny tattoo was nerve-wracking enough! I don't like needles...
A bit of a nitpick I guess, but uranium isn't usually considered a rare earth. The transactinides do share some chemistry with them, which is why the Spedding process for uranium purification was used after the war for lanthanides.
The problem with rare earths is that they are very evenly spread out in the crust, they don't tend to form concentrated ores the way most other metals do. There's actually more lanthanides around than many precious metals, for example, it's a problem of purification.
I think there's plenty of uranium in North America, especially in Canada.
The Nature Nanotechnology article is almost a year old. There are lots of people working on similar stuff, here's a review which mentions the Seeman work among many others (you probably need a library subscription to see the article, but the abstract should be accessible at least):
Electroosmosis works on ionic solutions. You set up a potential gradient and ions go to either the negative or positive ends, dragging the solvating fluid along. There are no ions in the rotating film experiment.
Now, there is a similar phenomenon called dielectrophoresis, which works on polar molecules, not just ions, and that may be close to the sort of thing going on here (water dipoles are perturbed by the fields near the interface, etc.), but in dielectrophoresis the frequency of the AC field is a crucial parameter. What really makes this weird is the fact that a static DC field is causing the rotation.
The two perpendicular fields are not identical. One of the fields is external, the other was applied as an electrode potential. So one of them is applied in air and gets screened at the interface, the other is applied directly to the cell and is not screened in the same way. I'm not sure what the consequences of this are, but I'm sure the difference is important.
Yes, liquid water under pressure at room temperature will indeed solidify. You need a hell of a lot of pressure, and the crystal form will be one of the other 12 known forms of ice, not the familiar ice(I) we know and love. In this case, it's actually ice(VII), a high pressure form consisting of two interpenetrating cubic lattices. The interpenetrating lattices allow more water to squeeze into a smaller space than in the liquid.
Water is a truly unique substance, from a physical chemistry standpoint. It often acts in ways that go against your physical intuition about how stuff should act. The obvious example everyone knows is the fact that the solid form is less dense than the liquid (so that ice floats), but there are many others. Lots of good reliable info here:
http://www.lsbu.ac.uk/water/
This is a hydrophilic channel. In a hydrophobic channel, the vapor phase is more stable than the liquid, so you get "cavitation" or "dewetting", as you approach the walls of the channel closer and closer, at some point all the water gets pushed out of the channel and the walls get pushed together.
The phenomenon is well understood in the hydrophobic case, both experimentally and in simulations. This experiment is new, up till now they couldn't get down to such small separations, but they are overstating the case when they claim that this is a complete surprise... as another poster said, many many simulation studies have suggested a structuring of water near hydrophilic surfaces.
Another neat thing happens when you have one wall hydrophobic and one wall hydrophilic. This has been dubbed a "Janus interface" after the two-faced Roman god, and there's a lot of interest in them.
Slashdot Mirror
Also, it reminds me of David Brin's "Earth", where in the near future drug laws have been near-universally made obsolete by the ability of anyone to get high using biofeedback techniques.
I used to TA for a physics course and one of the labs was about sound waves. We used empty plastic tubes and generated sound of a given frequency into them, then the students would change the length of the resonant cavity and find where the standing waves formed, and calculate the speed of sound from this. Then, the final part of the lab was to take the speakers and generate slightly different frequency tones and listen for the beat frequency. I guess this lab is now illegal in Oklahoma!
Oh yeah, just remembered another weird aspect of this story. He would be asked to give a "presentation", which consisted of slides that were prepared by his employers. He'd speak in English and have it "translated" as he went. Of course he had no clue what the presentation was supposed to be about, so he'd basically just babble nonsense for the duration.
I had a couple of friends go live in China for a couple of years. She was teaching english, he did that but also picked up some other "jobs", one of which involved, as far as he could tell, being shipped around to various places in China, dressed up in a suit, and having drinks poured down his throat until he couldn't walk anymore. Near as he could figure, he was supposed to be playing the role of the representative of a foreign company which was working with the Chinese outfit which had hired him, since that would make them look good to possible business partners. Sounds like a pretty surreal situation.
I've been thinking about getting a von Karman vortex street tattoo for years now. Maybe like one of those tribal patterns some people get around their upper arms. But cooler. Main thing that keeps me away is that getting my first tiny tattoo was nerve-wracking enough! I don't like needles...
http://unrulednotebook.files.wordpress.com/2009/03/turb_cyl_karman_vortex.png
A bit of a nitpick I guess, but uranium isn't usually considered a rare earth. The transactinides do share some chemistry with them, which is why the Spedding process for uranium purification was used after the war for lanthanides.
The problem with rare earths is that they are very evenly spread out in the crust, they don't tend to form concentrated ores the way most other metals do. There's actually more lanthanides around than many precious metals, for example, it's a problem of purification.
I think there's plenty of uranium in North America, especially in Canada.
The Nature Nanotechnology article is almost a year old. There are lots of people working on similar stuff, here's a review which mentions the Seeman work among many others (you probably need a library subscription to see the article, but the abstract should be accessible at least):
http://journals2.scholarsportal.info/details-sfx.xqy?uri=/14394227/v10i0015/2420_catdn.xml
Electroosmosis works on ionic solutions. You set up a potential gradient and ions go to either the negative or positive ends, dragging the solvating fluid along. There are no ions in the rotating film experiment.
Now, there is a similar phenomenon called dielectrophoresis, which works on polar molecules, not just ions, and that may be close to the sort of thing going on here (water dipoles are perturbed by the fields near the interface, etc.), but in dielectrophoresis the frequency of the AC field is a crucial parameter. What really makes this weird is the fact that a static DC field is causing the rotation.
The two perpendicular fields are not identical. One of the fields is external, the other was applied as an electrode potential. So one of them is applied in air and gets screened at the interface, the other is applied directly to the cell and is not screened in the same way. I'm not sure what the consequences of this are, but I'm sure the difference is important.
Yes, liquid water under pressure at room temperature will indeed solidify. You need a hell of a lot of pressure, and the crystal form will be one of the other 12 known forms of ice, not the familiar ice(I) we know and love. In this case, it's actually ice(VII), a high pressure form consisting of two interpenetrating cubic lattices. The interpenetrating lattices allow more water to squeeze into a smaller space than in the liquid. Water is a truly unique substance, from a physical chemistry standpoint. It often acts in ways that go against your physical intuition about how stuff should act. The obvious example everyone knows is the fact that the solid form is less dense than the liquid (so that ice floats), but there are many others. Lots of good reliable info here: http://www.lsbu.ac.uk/water/
This is a hydrophilic channel. In a hydrophobic channel, the vapor phase is more stable than the liquid, so you get "cavitation" or "dewetting", as you approach the walls of the channel closer and closer, at some point all the water gets pushed out of the channel and the walls get pushed together.
The phenomenon is well understood in the hydrophobic case, both experimentally and in simulations. This experiment is new, up till now they couldn't get down to such small separations, but they are overstating the case when they claim that this is a complete surprise... as another poster said, many many simulation studies have suggested a structuring of water near hydrophilic surfaces.
Another neat thing happens when you have one wall hydrophobic and one wall hydrophilic. This has been dubbed a "Janus interface" after the two-faced Roman god, and there's a lot of interest in them.