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Motor Made From Liquid Film
KentuckyFC writes "Last year, a group of Iranian physicists made a puzzling discovery. They placed a thin film of water in a small cell and bathed it in two perpendicular electric fields. To their surprise this caused the water to rotate. They called their device a liquid film motor and posted on the web a cool set of movies showing the phenomenon. The puzzle is this: the electric fields are static, so what's driving the motor? Now another group of physicists has the answer: a complex interaction between the electric field, the cell container and the liquid causes water to move along the cell wall. Crucially, it moves in opposite directions on opposite sides of the cell and so sets up a circular flow. The phenomenon works only when friction and surface tension are significant forces so the effect is entirely scale dependent. That's probably why we haven't seen it before and also why it could have important implications for microfluidic devices such as lab-on-a-chip."
Nice to see at least something coming out of that region of the world nowadays that has no relation to terrorists or nukes.
As for the actual story: this can be used to build the world's smallest washing machine.
You can't handle the truth.
the ayatollah has made science a high priority:
http://en.wikipedia.org/wiki/Ali_Khamenei
he recongizes the truth: iran will be a second rate power unless it leads in the field of science, through which it retains its independence and preeminence. this is why attacking iran's nuclear pursuits is hopeless, since iran attaches so much pride in iranian science and technology exploits. they just launched a satellite too. but all of these advances came from science and technology stolen or borrowed from other countries
but the history of persian science is a rich one, and there is no reason its future shouldn't be bright as well, if only the ayatollah would also realize that the preeminence of the west in science came only after the enlightenment
what else happened in the west during the enlightenment? religion was questioned. this is not a mistake or a coincidence: the questioning of religion is inseperable from being a strong scientific thinker. the probing mind of a scientist must be able to question everything, no taboos, in order to do the best science one can. you train young minds to question everything, and in this way, you make great scientists
so dear ayatollah: i celebrate your desire to reassert persia at the forefront of science and technology. so why don't you further this great goal along by relaxing the stifling theocratic censorship of your society, ensuring bright young minds are trained to their utmost? in order to ensure that persian civilization flowers again, let little discoveries like this thin film motor not by isolated gems, but instead be the beginning of a rich tapestry of persian thought
do that, by relaxing your fundamentalist stranglehold on the mind of the young iranian
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
It's been about 20 years since I took E&M Physics, but... How exactly would "two perpendicular electric fields" be different from one diagonal electric field equal to the vector sum? Mathematically, you can only describe two things as "perpendicular" if they are reasonably linear and uniform.
I wonder if you could use this effect to make a sort of a propulsion system for a small submarine. If you don't have a propeller at all, and were just spinning water around, it could be very quiet.
This is my sig.
I don't understand. They seem to be setting up two static, plane electric fields at some angle to one another. Surely the resultant field is just another field at a different angle? Say the two fields are E and J , with
E = ( E , 0 , 0 )
J = ( 0 , J , 0 )
Then you've just got the resultant field, E' = E + J , where
E' = ( E , J , 0 )
which is just another static, plane electric field. So, given that two fields are really equivalent to one, if you set up just the resultant field in the first place, would this motor effect still occur?
What am I missing?
I'd love to know how they got stable films, showing thin-film optical interference, of thicknesses on the order of several millimeters (stated a couple of times in the paper). They specifically call it a "suspended liquid film" and say that the z-boundaries are considered "free", so I don't think these films are sitting in a little box with just the top open.
This sounds awfully close to electroosmotic flow a phenomenon that has been known about for 200 years. Maybe someone better informed in this field could clarify the difference.
Just as another example of Iranian research: ridiculously strong concrete. High strength concrete generally has a compressive strength of 3,000 PSI or so. The person who wrote in about the situation had created concrete for the competition that was 16,000 PSI. 10,000 PSI is considered hard rock, and granite is 30,000 PSI. The Iranian concrete was *50,000-60,000* PSI. When it shattered, it damaged the testing equipment. They pulled it off using what appeared to be a quartz aggregate (160,000 PSI) and steel fibers. And this was at 28 days; concrete gets stronger over time.
Naturally, Wired spins it into the context of bunkers and nuclear weapons, like we do with everything that comes out of Iran. How long until this thin-film motor gets portrayed as something nefarious?
"Next on Fox: An Iranian art student paints a prize-winning portrait of a sunflower. Is it really a secret code for transferring nuclear secrets? Find out after the break."
Iran is trying their damndest not to be seen as an intellectual backwater. And while they're not up to western standards, nor are western stereotypes of Iranian academic achievement generally justified. There are now six times as many university students in Iran today as there were in 1979 when the Shah was overthrown -- largely because tuition, room, and board are paid for by the government, which is trying to improve their education standards. Here's a fair summary of the situation today. They're no shining star when it comes to education, but they're not backwoods yokels either.
Another way to put it: Iran has two of the top 500 universities in the world, as ranked by QS. That puts them tied for 42nd in terms of top-500 universities, with . 140 countries don't have any top-ranking universities at all. There's not a single country in the Carribean with a top-500 university, only two countries in all of Africa (Egypt=1, South Africa=4), and so on. The lion's share are in the US -- 123, followed by the UK (50), Germany (42), France (38), and Japan (36). Iran ranks better than Lithuania, Saudi Arabia, Uruguay, Egypt, Slovenia, Colombia, Peru, UAE, Romania, Sri Lanka, and Bangladesh (1 each), but below Mexico (3) and Poland, Portugal, Pakistan, Denmark, Israel, Norway, South Africa, Chile, Phillipines, Czech Republic, and Argentina (4 each).
Are there any deer in the theater tonight? Get 'em up against the wall.