In high school and college, every now and then someone would have surgery or have a bad injury, and they'd come back from the doctor bragging about the drugs they got. It was like a free pass to get high, and no one was ever concerned that it might lead to addiction because the drugs were prescribed by a doctor, so of course they aren't dangerous. It seems due to a failure to educate young people properly and a success on the drug companies' part to make their product seem like magic.
Alta devices has a record efficiency of 28.8% (not 24%, as quoted in the article) specifically for a single junction solar cell. This cell technically has four junctions, for which I'm not aware of any world records; however, Boeing spectrolab created a five junction cell with the world record for non-concentrated light (38.8%). I'm not aware of the records for spectrum splitting cells, so it's possible that Alta made a spectrum splitting cell with 24% efficiency and that this is the new world record for such a cell, though it's not particularly ground-breaking in terms of impact since it doesn't solve the major problems that make these high efficiency cells so expensive (the triple junction cell still requires an expensive substrate and an expensive process for depositing the films)
Basically the same catalysts have been reported previously. In this new paper, they don't bother to highlight the fact that their films are extremely thick, so of course they get great catalytic activity (though it's an oxide, so the series resistance might just be a problem...)
Newton's third law doesn't necessarily mean the same amount of work is done on both objects. For instance, consider a block attached to a spring attached to a wall. With the spring initially compressed, it does work on the block as it moves away from the wall, but the spring does negligible work on the wall because the wall is not moving. Substitute pressurized gas for spring, bullet for block, and rifle for wall. An added complication is that the force on the bullet is actually due to gases in the barrel, so if the gases are accelerating then the rifle will feel a different force than the bullet.
The best way to analyze the situation is using conservation of momentum. Assuming the bullet and rifle are both at rest before firing, total momentum must be zero. Take.01kg for the bullet mass, 1kg for the rifle mass, and 1000 m/s for the muzzle velocity. Then.01kg * 1000 m/s = 1 kg * V_rifle --> V_rifle = 10 m/s. In contrast, the kinetic energy of the bullet is.01kg * (1000 m/s)^2 = 10^4 J versus 1kg * (10 m/s)^2 = 100 J, so I would expect the bullet to have around two orders of magnitude greater energy.
You could check wikipedia for "Free Recoil" and "Muzzle Energy" if you want to see how accurate my approximation is.
The two major flaws in your argument are that radiation doses (in rem or Sv) are calculated using a "quality" factor that takes into account the type of radiation and the tissue that absorbs it, and the fact that the units are in energy/mass so the calculations _should_ already take into account the frequency dependence of photon energy. But I do agree that people should be more clear when they say "radiation"--I get the feeling that people hear x-rays and they think of nuclear decay involving protons and neutrons, when x-rays are just high energy light. And what does "background radiation" really mean? Everything around me is radiating but it's mostly infrared light and I'm not too worried about my exposure to infrared, even cumulatively over a long time period.
"Oh how awful. Did he at least die peacefully?...To shreds, you say? Tsk, tsk, tsk. Well, how's his wife holding up?...To shreds, you say? Very well, then."
The most useful thing I learned in high school chemistry was that units behave like variables. I wouldn't have made it far as a physics major if I didn't recognize when the result of a formula has the wrong units or that you can't add meters to seconds.
My understanding of an "entropic force" is that it can be described in terms of fundamental forces. The pressure in an ideal gas, for instance, can be derived by looking at the impulse created by a single molecule, and then extending that to a collection of N molecules. This guy seems to be saying that gravity is an entropic force and therefore NOT a fundamental force, but it seems to me that entropic forces are just an abstraction that allows us to ignore the underlying fundamental forces.
Of course, I didn't read the whole article, but what I read was poorly written and that doesn't inspire a lot of confidence. Maybe I'll take another look if it gets published.
If they aren't encrypted, I assume that means that these devices don't actually meet the NIST standard. Couldn't there be a lawsuit for advertising the drives as such?
And to the people who say that more energy is consumed in producing corn I'd also ask for a source. According to the DOE, has a positive energy balance. (Granted, the source is the government, so I guess they're only saying that because of corn lobbyists)
I'm honestly willing to hear claims to the contrary, but all I see here on slashdot is a bunch of people saying that ethanol is bad without citing any research (even TFA didn't cite any original research)
Windows are solar collectors. Build enough of them in the right configuration and you can save a lot on your heating. Plant some deciduous trees or have a low overhang to block light during warmer months, and you can keep cool as well.
Regardless, there was no reason to bring creationism into this article in the first place. Mentioning it only annoys people and masks any actual scientific discussion of the article. But I guess this is slashdot and we don't have any insightful comments that are actually relevant to the posted articles.
I wished I'd learned how to solder, put together circuits, weld, use machinery, etc. as a kid. Those things would come in handy now that I'm an undergraduate physics student (especially since I'm considering an engineering degree as well) It's hard to work on a reasearch project when you have no idea how to build the experimental setup you need! Not to mention that the university doesn't have the budget for us to have any part we need ordered/machined
"Complete liberty of contradicting and disproving our opinion, is the very condition which justifies us in assuming its truth for purposes of action; and on no other terms can a being with human faculties have any rational assurance of being right."
I'm not saying teachers should be spouting any nonsense, but I have heard more or less scientific arguments that tried to refute evolution/old earth theory. And they haven't stood up to the counter arguments. I'm glad I heard both sides.
Reproducing the results only proves that you both have the same systematic error in your experiment.
Re:That was never "obvious".
on
Can Time Slow Down?
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· Score: 2, Interesting
A common misconception is that the Catholic church initially opposed Copernicus' Heliocentric model, when in fact it was the scientific community that was skeptical (and I think didn't fully accept it until Newton) Also, it's rather ironic that people now believe the church had a problem with the model because it put us out of God's center of attention or something, but the center of the universe was actually regarded as the "lowest" place (look at how Dante put Hell in the center of the Earth, and hence the center of the universe)
That said, the Catholic Church later censored Copernicus because of certain passages that it interpreted literally that seemed to conflict with his model (the one I remember offhand is about the sun being held in place for a certain period of time...)
But at least slashdot has options to decrease bandwidth usage. Very nice to avoid all the bells and whistles when all you want is to read the article and comments.
Slashdot Mirror
In high school and college, every now and then someone would have surgery or have a bad injury, and they'd come back from the doctor bragging about the drugs they got. It was like a free pass to get high, and no one was ever concerned that it might lead to addiction because the drugs were prescribed by a doctor, so of course they aren't dangerous. It seems due to a failure to educate young people properly and a success on the drug companies' part to make their product seem like magic.
Alta devices has a record efficiency of 28.8% (not 24%, as quoted in the article) specifically for a single junction solar cell. This cell technically has four junctions, for which I'm not aware of any world records; however, Boeing spectrolab created a five junction cell with the world record for non-concentrated light (38.8%). I'm not aware of the records for spectrum splitting cells, so it's possible that Alta made a spectrum splitting cell with 24% efficiency and that this is the new world record for such a cell, though it's not particularly ground-breaking in terms of impact since it doesn't solve the major problems that make these high efficiency cells so expensive (the triple junction cell still requires an expensive substrate and an expensive process for depositing the films)
From the makers of submarine screen doors
Basically the same catalysts have been reported previously. In this new paper, they don't bother to highlight the fact that their films are extremely thick, so of course they get great catalytic activity (though it's an oxide, so the series resistance might just be a problem...)
Newton's third law doesn't necessarily mean the same amount of work is done on both objects. For instance, consider a block attached to a spring attached to a wall. With the spring initially compressed, it does work on the block as it moves away from the wall, but the spring does negligible work on the wall because the wall is not moving. Substitute pressurized gas for spring, bullet for block, and rifle for wall. An added complication is that the force on the bullet is actually due to gases in the barrel, so if the gases are accelerating then the rifle will feel a different force than the bullet.
The best way to analyze the situation is using conservation of momentum. Assuming the bullet and rifle are both at rest before firing, total momentum must be zero. Take .01kg for the bullet mass, 1kg for the rifle mass, and 1000 m/s for the muzzle velocity. Then .01kg * 1000 m/s = 1 kg * V_rifle --> V_rifle = 10 m/s. In contrast, the kinetic energy of the bullet is .01kg * (1000 m/s)^2 = 10^4 J versus 1kg * (10 m/s)^2 = 100 J, so I would expect the bullet to have around two orders of magnitude greater energy.
You could check wikipedia for "Free Recoil" and "Muzzle Energy" if you want to see how accurate my approximation is.
The two major flaws in your argument are that radiation doses (in rem or Sv) are calculated using a "quality" factor that takes into account the type of radiation and the tissue that absorbs it, and the fact that the units are in energy/mass so the calculations _should_ already take into account the frequency dependence of photon energy. But I do agree that people should be more clear when they say "radiation"--I get the feeling that people hear x-rays and they think of nuclear decay involving protons and neutrons, when x-rays are just high energy light. And what does "background radiation" really mean? Everything around me is radiating but it's mostly infrared light and I'm not too worried about my exposure to infrared, even cumulatively over a long time period.
"Oh how awful. Did he at least die peacefully?...To shreds, you say? Tsk, tsk, tsk. Well, how's his wife holding up?...To shreds, you say? Very well, then."
The most useful thing I learned in high school chemistry was that units behave like variables. I wouldn't have made it far as a physics major if I didn't recognize when the result of a formula has the wrong units or that you can't add meters to seconds.
My understanding of an "entropic force" is that it can be described in terms of fundamental forces. The pressure in an ideal gas, for instance, can be derived by looking at the impulse created by a single molecule, and then extending that to a collection of N molecules. This guy seems to be saying that gravity is an entropic force and therefore NOT a fundamental force, but it seems to me that entropic forces are just an abstraction that allows us to ignore the underlying fundamental forces. Of course, I didn't read the whole article, but what I read was poorly written and that doesn't inspire a lot of confidence. Maybe I'll take another look if it gets published.
If they aren't encrypted, I assume that means that these devices don't actually meet the NIST standard. Couldn't there be a lawsuit for advertising the drives as such?
The nsf conducted a survey that found that 51% of people in the U.S. thought antibiotics kill viruses as well as bacteria: http://www.nsf.gov/statistics/seind02/c7/c7s1.htm
My handheld GPS also has a built-in compass.
Why would you want to kill someone in public?
According to Wikipedia, as of 2008-04-30, ethanol production is no longer subsidized. Care to provide a source countering that?
And to the people who say that more energy is consumed in producing corn I'd also ask for a source. According to the DOE, has a positive energy balance. (Granted, the source is the government, so I guess they're only saying that because of corn lobbyists)
I'm honestly willing to hear claims to the contrary, but all I see here on slashdot is a bunch of people saying that ethanol is bad without citing any research (even TFA didn't cite any original research)
Yes, but I also use my Xbox to heat my home during winter. Try that with a Wii.
"Windows with solar collectors built-in"
Windows are solar collectors. Build enough of them in the right configuration and you can save a lot on your heating. Plant some deciduous trees or have a low overhang to block light during warmer months, and you can keep cool as well.
Regardless, there was no reason to bring creationism into this article in the first place. Mentioning it only annoys people and masks any actual scientific discussion of the article. But I guess this is slashdot and we don't have any insightful comments that are actually relevant to the posted articles.
I wished I'd learned how to solder, put together circuits, weld, use machinery, etc. as a kid. Those things would come in handy now that I'm an undergraduate physics student (especially since I'm considering an engineering degree as well) It's hard to work on a reasearch project when you have no idea how to build the experimental setup you need! Not to mention that the university doesn't have the budget for us to have any part we need ordered/machined
"Complete liberty of contradicting and disproving our opinion, is the very condition which justifies us in assuming its truth for purposes of action; and on no other terms can a being with human faculties have any rational assurance of being right." I'm not saying teachers should be spouting any nonsense, but I have heard more or less scientific arguments that tried to refute evolution/old earth theory. And they haven't stood up to the counter arguments. I'm glad I heard both sides.
Reproducing the results only proves that you both have the same systematic error in your experiment.
A common misconception is that the Catholic church initially opposed Copernicus' Heliocentric model, when in fact it was the scientific community that was skeptical (and I think didn't fully accept it until Newton) Also, it's rather ironic that people now believe the church had a problem with the model because it put us out of God's center of attention or something, but the center of the universe was actually regarded as the "lowest" place (look at how Dante put Hell in the center of the Earth, and hence the center of the universe)
That said, the Catholic Church later censored Copernicus because of certain passages that it interpreted literally that seemed to conflict with his model (the one I remember offhand is about the sun being held in place for a certain period of time...)
News Flash: Japanese less likely to die from U.S. bombs
But at least slashdot has options to decrease bandwidth usage. Very nice to avoid all the bells and whistles when all you want is to read the article and comments.
http://www.engadget.com/2006/04/26/apple-patent-em beds-thousands-of-cameras-among-lcd-pixels/
I dunno, sounds like this is just for touchscreen applications, but Apple was focusing on using the screen as a webcam. What the difference between "optical sensors" and "thousands of cameras" is I do not know.
In United States, government watches YOU!