1. Produces a narrow beam of light 2. Produces monochromatic light 3. Produces coherent light
Actually, condition 3 is the only one that is necessarily true of all lasers. There are solid-state lasers with very wide bandwidths, thereby violating condition 2, and it is easy to expand or diffuse a laser beam, thereby violating condition 1.
To be honest, there is little point in creating an omnidirectional laser source, at least for SETI purposes, because that only degrades the signal-to-noise ratio. However, if you want to do so, it's pretty trivial: shine the laser beam into a high numerical-aperture microscope objective, and the wavefronts that emerge beyond the focal point will be an excellent approximation of ideal spherical waves.
I am not a nuclear engineer, but I suspect that you aren't one, either. It seems plausible to me that one could safely handle irradiated graphite with just blue latex gloves. The typical radioactive emissions from carbon isotopes are alpha and beta particles, which don't even penetrate skin and thus pose little to no carcinogenic risk. The blue gloves probably aren't even for radiation protocol--they're probably just to keep their hands from getting dirty with graphite dust.
You've complaining about a $70 textbook?! In engineering, new textbooks often cost between $100 and $150, and I've bought one used textbook for $150 (it would have been $200 new!:-o).
This will in no way deter "terrorists" form blowing up buildings.
Not everything is about the "war" on terrorism. Have you ever been to downtown Baltimore? If so, you would probably know that these cameras aren't so much about catching terrorists and are more about trying to reduce the horrific crime rate.
Feh... asymetric works the other way, too. I have broadband service and when using BitTorrent I often find myself uploading to others far more than I received before the download is complete.
Just last week I had two students turn in spline code that was a bad C translation of Fortran code. I haven't hunted down the source but their codes were identical and neither student knew Fortran.
They probably lifted it directly from Numerical Recipes in C...:-p
There actually are a number of different solid phases of water, which are known as ice-one, ice-two, etc., all the way up to ice-twelve. So there is in fact an ice-nine, but fortunately it has none of the properties attributed to ice-nine by Kurt Vonnegut. See this link for more information about the different solid phases of water.
Will a new calculator ever be marketed to make me want to turn in my trusty HP-41CX? (which btw runs on "normal" batteries available in any drugstore, so I never have to worry about the built-in custom rechargable battery dying like with my old, now completely useless TI calculators.
You must not have tried a TI calculator in a long time. The entire TI-8x line runs on standard AAA batteries.
Along with the TI-86, 92, and 95. I remember when the TI-92 was the "Amazing Calculator" only the rich kids could afford. Kind of weird they continue with the TI-8x line but not the 9x.
Probably because the TI-92 is banned from just about every standardized exam, while the TI-89, which has equivalent functionality in a different form factor, is not.
> > The thing just looks like a big balsa wood model, and it isn't very detailed > > Yeah, and even more disappointing - it's not to scale. I mean, jeez, what's the point?
Even more disappointing than that, it doesn't work!:-p
A single helium atom is not sufficient to affect the quantum state of the carrier photons. If that were the case, the quantum link would not work at all, seeing as how the optical fiber in which the photons propagate is composed of much larger atoms like silicon and oxygen. So to effectively DoS the cable, you would need to cut the fiber. Depending on how well armored the cable is, you might need anything from a large ax to a small pair of wire cutters.
The power supply for charging the battery puts out about 60 Watts of power. The article mentions that instead of taking an hour to charge, these batteries only take half a minute. That's 120 times the power, which means the total power used by a charger for my laptop using these batteries would be...
7200 Watts! Holy hairdryers batman! With power consumptions like this, your athelon wouldn't be the only thing that's ON FIRE in your laptop!
You assume that all of the power used to charge the battery is dissipated as heat. If that were the case, rechargable batteries would be useless since that would mean the battery didn't store any of the energy you put into it. I think I agree that your qualitative conclusion, though; a 90% efficient rechargable battery would dissipate 720 watts of heat, which is still quite a bit of thermal energy.
A quick response, since you (and others) seem to have misunderstood me. I am not advocating that everything should be built from source. I'm just observing that if you compile a program yourself, you can optimize it for the exact hardware configuration you have (say, P4 with SSE2) instead having to compile for the lowest common denominator (i386, for example). For a lot of applications, the performance hit probably isn't noticable, but you must admit that there are applications where it is worth it to squeeze as much performance out of the code as you can. For those applications, it is worth the extra effort to build your own optimized binaries from sources instead of using a prebuilt package.
I would have to agree about using packages. One gripe I have about building from source is that most packages do not have "make uninstall".
You need to discover FreeBSD and the godsend known as the Ports Collection. To remove a package built from source, all you have to do is enter the source directory and type "make deinstall".
From reading the press release from 1998, it sounds like they defined the break-even condition as when the output power from the plasma exceeds the power input required to form the plasma. However, one generally would like to keep the plasma confined, and that also requires input power, so while they may have exceeded plasma break-even, they might not have exceeded overall break-even, which is a necessity for a viable power plant.
Nope. You don't know which definition I meant, because there are 4 on that page, and 3 of them have "written" as the first meaning. The other has it as the second.
Of the four sources on the page, the only two that I would consider authoritative in any way are American Heritage and Webster's, and both pale in comparison to the OED. I take issue with the fact that you neglect Webster's first definition of the word "graphical," which supports the pictoral interpretation over your written word interpretation. In any case, to assert that the written word interpretation is dominant in modern English usage is absurd.
Thus they are unanimous that the claim "Graphical is not Text" is absolutely, completely false.
I actually agree with you on this point. The point of contention for me this statement in your parent post:
In fact to be pedantically correct, a photograph or diagram isn't graphical. Only written text is by-definition "graphic".
To claim that "graphical" only describes written text is an untenable position, and that's the only reason I was compelled to respond to your comment. That claim contradicts both modern and not-so-modern English usage.
I doubt that, as it contradicts other words with the "graph" base such as "graphology" and "digraph". The historical record clearly shows that although "graph" meant "visible shapes", it was first used to indicate the shapes of letters.
Fine, however it does not follow that we should interpret all "graph" words pertain only to written text. As far as how the Greek root grafikos was first used, that is open to debate since we cannot proved when it was first used or what its intended meaning was. For all we know, the written word interpretation could be a bastardization of the pictoral interpretation.
Slashdot Mirror
Actually, condition 3 is the only one that is necessarily true of all lasers. There are solid-state lasers with very wide bandwidths, thereby violating condition 2, and it is easy to expand or diffuse a laser beam, thereby violating condition 1.
To be honest, there is little point in creating an omnidirectional laser source, at least for SETI purposes, because that only degrades the signal-to-noise ratio. However, if you want to do so, it's pretty trivial: shine the laser beam into a high numerical-aperture microscope objective, and the wavefronts that emerge beyond the focal point will be an excellent approximation of ideal spherical waves.
I am not a nuclear engineer, but I suspect that you aren't one, either. It seems plausible to me that one could safely handle irradiated graphite with just blue latex gloves. The typical radioactive emissions from carbon isotopes are alpha and beta particles, which don't even penetrate skin and thus pose little to no carcinogenic risk. The blue gloves probably aren't even for radiation protocol--they're probably just to keep their hands from getting dirty with graphite dust.
/me has been curious about Orkut for a while now
elsonliu at gmail dot com
You've complaining about a $70 textbook?! In engineering, new textbooks often cost between $100 and $150, and I've bought one used textbook for $150 (it would have been $200 new! :-o).
Real engineers use slide rules! :-p
I suspect this new calculator policy will make the FE/PE exams a lot less popular...
To be more precise, a battery is multiple cannon, laser or otherwise.
Conserve energy...commute with the Hamiltonian!
A single helium atom is not sufficient to affect the quantum state of the carrier photons. If that were the case, the quantum link would not work at all, seeing as how the optical fiber in which the photons propagate is composed of much larger atoms like silicon and oxygen. So to effectively DoS the cable, you would need to cut the fiber. Depending on how well armored the cable is, you might need anything from a large ax to a small pair of wire cutters.
A quick response, since you (and others) seem to have misunderstood me. I am not advocating that everything should be built from source. I'm just observing that if you compile a program yourself, you can optimize it for the exact hardware configuration you have (say, P4 with SSE2) instead having to compile for the lowest common denominator (i386, for example). For a lot of applications, the performance hit probably isn't noticable, but you must admit that there are applications where it is worth it to squeeze as much performance out of the code as you can. For those applications, it is worth the extra effort to build your own optimized binaries from sources instead of using a prebuilt package.
From reading the press release from 1998, it sounds like they defined the break-even condition as when the output power from the plasma exceeds the power input required to form the plasma. However, one generally would like to keep the plasma confined, and that also requires input power, so while they may have exceeded plasma break-even, they might not have exceeded overall break-even, which is a necessity for a viable power plant.