HOLY COW! I CANT FUCKING BELIEVE IT! THAT WAS *AWESOME*!!! I CAN'T WAIT TO TELL BOB ABOUT THIS! HE'LL NEVER BELIEVE ME!
That sort of customer service experience is rare, to be sure, but let me tell you a little story about a company called Quantum Design. Now, Quantum Design is a small operation out of San Diego, and you've probably never heard of them. They make some very nice tools for physics and chemistry -- the Magnetic Property Measurement System, for example, combines a fantastically sensitive magnetometer with a superconducting magnet and a variable-temperature sample chamber. Slick, slick stuff.
Anyway, we have an MPMS on campus, and a PPMS (Physical Property Measurement System -- another cryostat with a big honking magnet and options to measure things like resistivity and heat capacity all the way from ~1.7 Kelvin to 400 K and up) in our lab. One day I was cooling a chip with some magnetic wires to ~10 K to make some measurements -- but the fridge wouldn't cool past 100! This is a problem. I called Quantum Design's tech support guys, and within a few hours they had walked me through some diagnostics and determined that the low-temperature thermometry was flaky. He gave us the option of sending the sample chamber to QD for them to repair, or having QD send us a new sample chamber and sending them the old one back. Well, I talked to my boss, who decided to just have them send the new sample chamber along and got the quote. The service guy said they could probably ship it out in a couple days; I asked if they could do it faster, because we need the fridge to work. Within 20 minutes he called me back and said they would ship it that afternoon. The next morning, by 10:00, the FedEx guy was there with our new hardware and instructions for the replacement procedure!
The total time from when the thermometer broke to when we had the new one installed and tested was less than 24 hours. And they gave us the shipping for free. That's what I call some service!
Well, OK, you can get the generic contact mode tips for cheap, but contact mode AFM tends to wreck your surface pretty thoroughly after a few passes. At a minimum, you need to be looking at tips in the TESP series -- and those are $30-40 each, in wafer quantities.
Just thought you'd like to know, since I can't message you directly (at least I don't think so)
The trouble with measuring a meter this way is that it's tricky, to say the least, to know the frequency of a laser beam to high enough precision for this to be a useful measurement. You'd basically have to do exactly what these guys are doing -- cool some ions to within a few microkelvins of zero, use them as a frequency reference and lock a laser to them. Then you'd have to do it again with a different frequency. Then you'd have to actually measure the intensity of the standing wave to high enough resolution that you could get a reasonable measurement. So basically, don't hold your breath.
Much more reasonable is to keep the current definition of the meter, which is the distance that light travels in 1/299,792,458 second in a vacuum. Then your better clock gives you a more accurate length standard without all the fuss.
It would provide *extremely useful* on-the-job training
Useful to whom? Certainly not to me... I can't think of a single skill that I would have learned in a year of military service that would be of use in my current position as a condensed-matter physicist. Do you really think that I would be a better scientist for a year of having some asshole sergeant inspecting my uniform and bouncing quarters off my bed? Hell no... it would just be a waste of what could otherwise have been a very productive year.
Well, you may be right about Red Delicious, since they're such a bastardized and unnaturally uniform strain -- but if you go out and get yourself an heirloom apple, maybe a Hudson's Golden Gem, and plant that sucker, well then Hudson's Golden Gems are what you will get. Many varieties are not propagated exclusively by grafting -- but you're not likely to find many of those in your supermarket. Hell, you'd be lucky to find some of them at all outside of New England, or maybe the Pacific Northwest.
I don't mind working for my money, but doesn't a technical education afford you some better jumping point? Is the market really that bad?
The market's pretty bad right now; I graduated last year from Dartmouth College, and a number of my friends were unemployed for several months after graduation (one is still without work, and another got his first offer last month). However: nobody I knew with a science or engineering degree was unable to find work. The offers I was fielding were in the $50-60K range, with a BA in Physics.
All that is not to say that it's hard to be happy with 30, especially in a city like Houston. I decided after much hand-wringing to go to grad school at Rice, and now I make a hair over 20K. Thing is, I'm happy with it because I really enjoy what I'm doing, my advisor is great, and eventually I'm getting a Ph.D. Plus, Houston is wicked cheap, so you really don't want for much with a 20K salary.
There are critics of Einstein that are academically serious and not off their rocker like some zero point/tesla fanatics. There have been critics of Einstein ever since he released his theories. You don't hear much about them as they are all heaped into one group and astrocized.
No, those people are also nuts. Consider the "Sagnac Experiment," in which it is claimed that a rotating interferometer experiences a shifting of the interference patterns. Now, I have not seen this experiment performed, nor have I read the papers, but it seems clear that an experiment performed in a non-inertial reference frame cannot possibly invalidate special relativity, the domain of which is explicitly stated to be only inertial frames. In fact, I would not be surprised at all to find that there is some sort of shift associated with an accelerating interferometer -- general relativity is extraordinarily difficult mathematically, but gravitational redshift is predicted, so a shift due to an accelerating frame would seem logical. However, it's a long way to go from a redshift associated with an accelerating reference frame to an invalidation of SR.
The rest of the site also reads like a tinfoil-hat type group... focusing a lot on why they are persecuted and not at all on actual evidence.
As far as releasing the data in real time goes, there are two good reasons not to do that. First, the research group that took the time to write the proposal and secure funding, and made the effort to actually build the probe, should by all rights get the first look at the data. It would be unfair to them to release the data immediately to the scientific community; they should get a chance to analyze it themselves and publish what they think is noteworthy. Rest assured that no matter what they publish, the data will be made available within a reasonable timeframe, and everyone else will go through it to see what they missed. The second reason is that there's nothing an average person, or even an average Ph.D. physicist, could reasonably hope to accomplish by looking at the mounds of raw data this probe will produce. It takes a lot of work to go from sensor voltages to some sort of usable data form, and more work still to go even from nicely formatted data translated into convenient units to a good picture of what's going on. General relativity is really, really hard, folks. There's a reason not many people do it. If you want to learn the differential geometry and all the other math and physics that goes into a detailed understanding of GR, be my guest -- just be prepared to spend 5 years or so doing it.
On Friends it was a million an episode, and I don't think the Friends crew ever wrote for the episode. On the other hand, the Friends crew had to actually get in front of a camera and do take after take to "get it right;" the Simpsons voice talent could show up in a bathrobe, and they each work about 1 hour per episode. You really can't make a fair comparison with Friends.
because Bell Lab's transistor contained gold it was not comercializable Say what? Bell Labs invented the bipolar junction transistor (P-doped, then N-doped, then P-doped Si or Ge) (also available in NPN), as well as zone refining, the first technology which could create pure enough Si to build a working transistor. And as far as Shockley's personal character, who cares? He got the job done. Don't minimize the contributions of Bell Labs to semiconductor physics; they were tremendously helpful.
AT&T Labs is a distinct entity from Bell Labs. Also, the original point-contact transistor was described and I think patented in something like 1910. Granted, it didn't work well as designed, which is why miniaturization didn't start until semiconductors that really work were invented at Bell, but a gating effect can be seen in the original point-contact design.
I didn't mean to imply that I work with Smalley, but my lab is right next to his, I talk to some of his students, and I was there for the pitch he gave to all of us first-year physics grads. Right now, he wants to spend the next 5 years doing whatever it takes to make carbon nanotubes an industrially viable material. That means coming up with a way to produce exactly the nanotubes you want in mass quantities. Armchair nanotubes could be far better for long-distance power transmission than copper -- electron transport through them is almost ballistic. Other types of nanotubes, if they can be spun into fibers, would be as great a leap forward in materials science as was the invention of steel. The energy stuff I'm not too familear with, but he knows exactly what he wants to do on the materials science end.
The basic missing factor in all this is the total lack of a high thrust, high efficiency rocket engine of isp greater than 100,000
Yes, high thrust and Isp > 100,000/s would be wonderful. Unfortunately, it would require approximately one metric fuckton of power to even approach what one might reasonably call "high" thrust with such a large specific impulse. The tradeoff between fuel efficiency and thrust is unavoidable, and is directly related to the fact that we simply can't put an arbitrarily big power plant in orbit. For a trip to Mars, even an Isp of 30,000 is overkill; it's much better to burn the extra fuel and get there faster with humans aboard.
Of course, we also need lightweight radiation shielding and a way to keep the astronauts' bones from deteriorating, so that they'll still be able to stand when they get there... we've got a long way to go.
Smalley of Rice thinks nano will solve the world's energy needs. A laudable goal but harly a roadmap or vision
Well... yes and no. There is no roadmap at present, but that should hardly be surprising, since Smalley wants to fix the world's ills with carbon nanotubes, which are a material that we've only been able to make for the last few years, and which we still can't do in industrially useful quantities or purities (Smalley's HiPCO method produces nanotubes in kilogram quantities, but it produces essentially random variants of the nanotubes, and they come out of the machine basically as molecular spaghetti). However, most people here at Rice would consider Smalley to be a visionary; one need only hear him talk about where he wants to take his research program in the next five years to be convinced of that. He has a vision, and unlike Drexel's, it is a realistic and (hopefully) attainable one.
(Yes, I think Drexel is a nut, mainly on thermodynamic grounds. Please don't flame me unless you have some ideas on how a "gray goo" type nanoassembler would stay fed in the wild.
...not in any computationally useful sense, anyway. Now, I'm not knocking this research, because it's a great way to make a bunch of nanotubes and examine them quickly (much faster than the usual process of making nanotubes, decorating a surface with them, hoping some of them line up with the traces you've deposited, etc.) -- but the fact remains that this is still basically an aleatoric process. You grow a bunch of nanotubes, and you know that some of them are going to be your nice metallic armchair nanotubes, some are going to be your nice semiconducting zigzags, and some are going to be junk. We don't have any way of controlling what type of nanotube we want to grow yet, nor do we have any way of getting yields high enough to make a traditional microprocessor. Right now, maybe 10 percent of the "transistors" you make out of molecules actually act like transistors. Since your Athlon is junk if even a few of its transistors or interconnects go bye-bye, and even Teramac didn't try to run with 90 percent of its transistors failed, it is clear that nanotubes for desktop-type computation are way out on the horizon.
Building a stable, sustained, controllable fusion reaction is relatively easy. That isn't, and never has been, the problem. You contain the plasma in a magnetic field that has a single half-twist in it.
Building a stable, sustained, controllable fusion reaction is _incredibly_ difficult. Yes, plasma can be contained by a toroidal magnetic field, FSVO "contained." A nice, cold plasma, at a few tens of thousands of degrees? No problem. At higher temperatures, though, collisions knock lots and lots of ions and electrons off-axis and into the walls of the reactor. This is a major mode of energy loss in magnetic confinement fusion experiments. As you mentioned, instabilities are also a tremendous problem, and that problem has not been solved.
Once you ignite your super-cold plasma, the nuclei are already much closer together, and can't move apart (density too high, plus magnetic field containing the plasma). Your ideal starting material would be a Bose-Einstein Condensate. You cannot get a better density than that, using just conventional means.
This is why you'd need the stupendous magnetic fields. What I'm suggesting is not fusion of a low-density gas, but fusion of a pseudo-liquid or pseudo-solid. To retain that kind of density, when the material is undergoing fusion, would require fields vastly greater than those currently used in fusion research.
As far as Bose-Einstein Condensates go, BEC's occur at temperatures in the nanokelvin range -- that's a full, what, 12 or 13 orders of magnitude too low in thermal energy to overcome the Coulomb potential keeping the nuclei apart. BEC's are notoriously tricky to create; you need to go through several cooling stages involving precisely tuned ultrastable lasers, and at the end of all that work, you get a ball of maybe a few billion atoms. It is simply not feasible to produce BEC's at any larger scale, nor to keep them condensed at fusion temperatures.
And as stupendous magnetic fields go, well, the best anyone can do right now is a sustained field of about 25 Tesla. I don't know offhand what fields they use in Tokamak experiments, but I'm betting it's no more than 10 Tesla, nor less than 1. Either way, there is no way we know of to make steady-state magnetic fields "many orders of magnitude stronger."
It's late now, and I'm getting tired, but suffice it to say that there's a lot more to be done than just making everything bigger. The energy scales are enormous, nobody really knows how to keep a plasma hot and contained, and it's going to take a lot more R&D before we can get usable energy out of fusion.
OK, lots of people have read "Prey" or one of the other Shiny! Exciting! Books! that talk about the "Gray Goo problem". Simply stated, this is that nanoassemblers which are trained to self-replicate could potentially go bonkers and start turning the entire planet into more assemblers. As Homestar Runner might put it, "That's just ridiculous" -- and yet this is what some people lose sleep over! The reason that nanoassemblers will never be able to replicate in an uncontrolled environment, and therefore will never take over the world, is that they need energy to function. Lots of it. Breaking pi and sigma bonds can be ridiculously expensive, requiring several eV of energy in some systems. Pulling a carbon out of a single-walled nanotube takes over 10 eV. Where does the energy come from? Absent a large and complex digestive system, the assemblers will have to be fueled ahead of time or provided with a simple energy source along with their raw materials. These robots will not be able to find the energy they need to keep going in the wild. That's why Smalley's not worried about runaway nanobots. The extreme difficulty of doing "machine-phase chemistry" is another good reason, by the way -- assuming machine-phase chemistry is even possible, how are the nanobots supposed to create a clean enough environment to do their work in the wild? If machine-phase chemistry can be accomplished at all, it will be a much more complicated affair, I think, than Drexler would have us believe.
Physics in the US is uniformly taught in SI units at the high school/university levels, at least to start; if you're referring to "obscure constants" like epsilon-nought, well, those exist because SI uses units that are convenient for everyday electromagnetic measurements (mostly; Tesla and Farad are the two big stinkers there, but Volts and Amps are nice).
You get rid of the obscure constants by switching to cgs units, at the cost of having to use statvolts, which are absurdly large. Take it one step further with "natural units" or "space-time units," in which the speed of light is 1.
My point is, the obscure constants kids have to deal with in physics are not a result of the US system of measurement.
I've read the paper 3 or 4 times, and I honestly have no idea what they're claiming. The paper itself is pretty opaque, and it's not at all clear whether they're talking about a real monopole or some sort of k-space mathematical artifact that just smells like one.
For those who don't have access to the article, these guys are making measurements on the anomalous Hall effect in a strontium ruthenate crystal. As far as I can tell, they are claiming that the fact that the transverse magnetoresistance is nonmonotonic with temperature implies an anomaly in the Berry phase of the electrons, hence a singularity in the vector potential and a magnetic monopole.
All this is in the first page. The actual discussion is thoroughly convoluted, and none of the CM faculty here seem to have a clue as to what the paper actually says. My guess is that they're just talking about something that looks like a monopole, but it's hard to say just from reading the paper.
Well, most students nationwide may have cell phones, but I'd say less than 10 percent of Dartmouth students do. For one thing, the reception is spotty at best, and I think only AT&T serves Hanover. For another, campus e-mail use is phenomenally high -- everyone uses Dartmouth's BlitzMail system, which works kind of like IMAP in that messages are stored centrally and you can get to them from any computer on campus (in fact, public computers are often referred to as "Blitz terminals.") You can even order pizza, Chinese, and all the other delivery options in town online -- so really the only use for a phone at Dartmouth is to call businesses (see who sells CO2 for your kegerator) or to call home. Dartmouth just made calling home free, which you have to admit is pretty nice.
As an aside, I disagree strongly that it is a waste of resources to have voice capabilities in dorms. In most cases, the wiring is already there, so it's a sunk cost -- might as well use it. When you're building new dorms, the marginal cost of adding phone wiring is minimal, so you might as well do it. Additionally, the capabilities have to be there for emergency services. Finally, there are plenty of people out there (myself included) who just don't have 500 bucks a year to spend on a cellular calling plan. All in all, it's definitely not a waste to keep phones in the dorms.
(Dartmouth '03, BTW, so I know what I'm talking about wrt campus phone use)
This is true... I need to be more careful posting late at night. The issue is that if an A record exists, the nameserver does not return NXDOMAIN. Since the spam filters look for an NXDOMAIN response, they are broken.
This will break sites like.museum, but it will mean my spam filtering works again.
It's worth noting that the latest ISC patch for BIND 9 supports excluding TLD's like.museum (which was chartered with a wildcard) and.de (which serves actual zone data from the.de root) from root-delegation-only.
So you can have your cake and eat it too in this case.
Slashdot Mirror
Yeah, but that's why God invented GPIB. If you've already got LabVIEW, it's a snap! Ditch the floppies.
That sort of customer service experience is rare, to be sure, but let me tell you a little story about a company called Quantum Design. Now, Quantum Design is a small operation out of San Diego, and you've probably never heard of them. They make some very nice tools for physics and chemistry -- the Magnetic Property Measurement System, for example, combines a fantastically sensitive magnetometer with a superconducting magnet and a variable-temperature sample chamber. Slick, slick stuff.
Anyway, we have an MPMS on campus, and a PPMS (Physical Property Measurement System -- another cryostat with a big honking magnet and options to measure things like resistivity and heat capacity all the way from ~1.7 Kelvin to 400 K and up) in our lab. One day I was cooling a chip with some magnetic wires to ~10 K to make some measurements -- but the fridge wouldn't cool past 100! This is a problem. I called Quantum Design's tech support guys, and within a few hours they had walked me through some diagnostics and determined that the low-temperature thermometry was flaky. He gave us the option of sending the sample chamber to QD for them to repair, or having QD send us a new sample chamber and sending them the old one back. Well, I talked to my boss, who decided to just have them send the new sample chamber along and got the quote. The service guy said they could probably ship it out in a couple days; I asked if they could do it faster, because we need the fridge to work. Within 20 minutes he called me back and said they would ship it that afternoon. The next morning, by 10:00, the FedEx guy was there with our new hardware and instructions for the replacement procedure!
The total time from when the thermometer broke to when we had the new one installed and tested was less than 24 hours. And they gave us the shipping for free. That's what I call some service!
Well, OK, you can get the generic contact mode tips for cheap, but contact mode AFM tends to wreck your surface pretty thoroughly after a few passes. At a minimum, you need to be looking at tips in the TESP series -- and those are $30-40 each, in wafer quantities.
Just thought you'd like to know, since I can't message you directly (at least I don't think so)
um... AFM tips cost quite a bit more than 30 bucks for a wafer. Try $50/tip, in bulk. Not cheap. The cantilevers are hard to make.
The trouble with measuring a meter this way is that it's tricky, to say the least, to know the frequency of a laser beam to high enough precision for this to be a useful measurement. You'd basically have to do exactly what these guys are doing -- cool some ions to within a few microkelvins of zero, use them as a frequency reference and lock a laser to them. Then you'd have to do it again with a different frequency. Then you'd have to actually measure the intensity of the standing wave to high enough resolution that you could get a reasonable measurement. So basically, don't hold your breath.
Much more reasonable is to keep the current definition of the meter, which is the distance that light travels in 1/299,792,458 second in a vacuum. Then your better clock gives you a more accurate length standard without all the fuss.
It would provide *extremely useful* on-the-job training
Useful to whom? Certainly not to me... I can't think of a single skill that I would have learned in a year of military service that would be of use in my current position as a condensed-matter physicist. Do you really think that I would be a better scientist for a year of having some asshole sergeant inspecting my uniform and bouncing quarters off my bed? Hell no... it would just be a waste of what could otherwise have been a very productive year.
Well, you may be right about Red Delicious, since they're such a bastardized and unnaturally uniform strain -- but if you go out and get yourself an heirloom apple, maybe a Hudson's Golden Gem, and plant that sucker, well then Hudson's Golden Gems are what you will get. Many varieties are not propagated exclusively by grafting -- but you're not likely to find many of those in your supermarket. Hell, you'd be lucky to find some of them at all outside of New England, or maybe the Pacific Northwest.
I don't mind working for my money, but doesn't a technical education afford you some better jumping point? Is the market really that bad?
The market's pretty bad right now; I graduated last year from Dartmouth College, and a number of my friends were unemployed for several months after graduation (one is still without work, and another got his first offer last month). However: nobody I knew with a science or engineering degree was unable to find work. The offers I was fielding were in the $50-60K range, with a BA in Physics.
All that is not to say that it's hard to be happy with 30, especially in a city like Houston. I decided after much hand-wringing to go to grad school at Rice, and now I make a hair over 20K. Thing is, I'm happy with it because I really enjoy what I'm doing, my advisor is great, and eventually I'm getting a Ph.D. Plus, Houston is wicked cheap, so you really don't want for much with a 20K salary.
Just my two cents...
There are critics of Einstein that are academically serious and not off their rocker like some zero point/tesla fanatics. There have been critics of Einstein ever since he released his theories. You don't hear much about them as they are all heaped into one group and astrocized.
No, those people are also nuts. Consider the "Sagnac Experiment," in which it is claimed that a rotating interferometer experiences a shifting of the interference patterns. Now, I have not seen this experiment performed, nor have I read the papers, but it seems clear that an experiment performed in a non-inertial reference frame cannot possibly invalidate special relativity, the domain of which is explicitly stated to be only inertial frames. In fact, I would not be surprised at all to find that there is some sort of shift associated with an accelerating interferometer -- general relativity is extraordinarily difficult mathematically, but gravitational redshift is predicted, so a shift due to an accelerating frame would seem logical. However, it's a long way to go from a redshift associated with an accelerating reference frame to an invalidation of SR.
The rest of the site also reads like a tinfoil-hat type group... focusing a lot on why they are persecuted and not at all on actual evidence.
As far as releasing the data in real time goes, there are two good reasons not to do that. First, the research group that took the time to write the proposal and secure funding, and made the effort to actually build the probe, should by all rights get the first look at the data. It would be unfair to them to release the data immediately to the scientific community; they should get a chance to analyze it themselves and publish what they think is noteworthy. Rest assured that no matter what they publish, the data will be made available within a reasonable timeframe, and everyone else will go through it to see what they missed. The second reason is that there's nothing an average person, or even an average Ph.D. physicist, could reasonably hope to accomplish by looking at the mounds of raw data this probe will produce. It takes a lot of work to go from sensor voltages to some sort of usable data form, and more work still to go even from nicely formatted data translated into convenient units to a good picture of what's going on. General relativity is really, really hard, folks. There's a reason not many people do it. If you want to learn the differential geometry and all the other math and physics that goes into a detailed understanding of GR, be my guest -- just be prepared to spend 5 years or so doing it.
On Friends it was a million an episode, and I don't think the Friends crew ever wrote for the episode.
On the other hand, the Friends crew had to actually get in front of a camera and do take after take to "get it right;" the Simpsons voice talent could show up in a bathrobe, and they each work about 1 hour per episode. You really can't make a fair comparison with Friends.
because Bell Lab's transistor contained gold it was not comercializable
Say what? Bell Labs invented the bipolar junction transistor (P-doped, then N-doped, then P-doped Si or Ge) (also available in NPN), as well as zone refining, the first technology which could create pure enough Si to build a working transistor. And as far as Shockley's personal character, who cares? He got the job done. Don't minimize the contributions of Bell Labs to semiconductor physics; they were tremendously helpful.
AT&T Labs is a distinct entity from Bell Labs. Also, the original point-contact transistor was described and I think patented in something like 1910. Granted, it didn't work well as designed, which is why miniaturization didn't start until semiconductors that really work were invented at Bell, but a gating effect can be seen in the original point-contact design.
I didn't mean to imply that I work with Smalley, but my lab is right next to his, I talk to some of his students, and I was there for the pitch he gave to all of us first-year physics grads. Right now, he wants to spend the next 5 years doing whatever it takes to make carbon nanotubes an industrially viable material. That means coming up with a way to produce exactly the nanotubes you want in mass quantities. Armchair nanotubes could be far better for long-distance power transmission than copper -- electron transport through them is almost ballistic. Other types of nanotubes, if they can be spun into fibers, would be as great a leap forward in materials science as was the invention of steel. The energy stuff I'm not too familear with, but he knows exactly what he wants to do on the materials science end.
The basic missing factor in all this is the total lack of a high thrust, high efficiency rocket engine of isp greater than 100,000
/s would be wonderful. Unfortunately, it would require approximately one metric fuckton of power to even approach what one might reasonably call "high" thrust with such a large specific impulse. The tradeoff between fuel efficiency and thrust is unavoidable, and is directly related to the fact that we simply can't put an arbitrarily big power plant in orbit. For a trip to Mars, even an Isp of 30,000 is overkill; it's much better to burn the extra fuel and get there faster with humans aboard.
Yes, high thrust and Isp > 100,000
Of course, we also need lightweight radiation shielding and a way to keep the astronauts' bones from deteriorating, so that they'll still be able to stand when they get there... we've got a long way to go.
Smalley of Rice thinks nano will solve the world's energy needs. A laudable goal but harly a roadmap or vision
Well... yes and no. There is no roadmap at present, but that should hardly be surprising, since Smalley wants to fix the world's ills with carbon nanotubes, which are a material that we've only been able to make for the last few years, and which we still can't do in industrially useful quantities or purities (Smalley's HiPCO method produces nanotubes in kilogram quantities, but it produces essentially random variants of the nanotubes, and they come out of the machine basically as molecular spaghetti). However, most people here at Rice would consider Smalley to be a visionary; one need only hear him talk about where he wants to take his research program in the next five years to be convinced of that. He has a vision, and unlike Drexel's, it is a realistic and (hopefully) attainable one.
(Yes, I think Drexel is a nut, mainly on thermodynamic grounds. Please don't flame me unless you have some ideas on how a "gray goo" type nanoassembler would stay fed in the wild.
so say "Fuehrer." That's the proper way to anglicize the German.
...not in any computationally useful sense, anyway. Now, I'm not knocking this research, because it's a great way to make a bunch of nanotubes and examine them quickly (much faster than the usual process of making nanotubes, decorating a surface with them, hoping some of them line up with the traces you've deposited, etc.) -- but the fact remains that this is still basically an aleatoric process. You grow a bunch of nanotubes, and you know that some of them are going to be your nice metallic armchair nanotubes, some are going to be your nice semiconducting zigzags, and some are going to be junk. We don't have any way of controlling what type of nanotube we want to grow yet, nor do we have any way of getting yields high enough to make a traditional microprocessor. Right now, maybe 10 percent of the "transistors" you make out of molecules actually act like transistors. Since your Athlon is junk if even a few of its transistors or interconnects go bye-bye, and even Teramac didn't try to run with 90 percent of its transistors failed, it is clear that nanotubes for desktop-type computation are way out on the horizon.
Interesting thoughts you have there...
Building a stable, sustained, controllable fusion reaction is relatively easy. That isn't, and never has been, the problem. You contain the plasma in a magnetic field that has a single half-twist in it.
Building a stable, sustained, controllable fusion reaction is _incredibly_ difficult. Yes, plasma can be contained by a toroidal magnetic field, FSVO "contained." A nice, cold plasma, at a few tens of thousands of degrees? No problem. At higher temperatures, though, collisions knock lots and lots of ions and electrons off-axis and into the walls of the reactor. This is a major mode of energy loss in magnetic confinement fusion experiments. As you mentioned, instabilities are also a tremendous problem, and that problem has not been solved.
Once you ignite your super-cold plasma, the nuclei are already much closer together, and can't move apart (density too high, plus magnetic field containing the plasma). Your ideal starting material would be a Bose-Einstein Condensate. You cannot get a better density than that, using just conventional means.
This is why you'd need the stupendous magnetic fields. What I'm suggesting is not fusion of a low-density gas, but fusion of a pseudo-liquid or pseudo-solid. To retain that kind of density, when the material is undergoing fusion, would require fields vastly greater than those currently used in fusion research.
As far as Bose-Einstein Condensates go, BEC's occur at temperatures in the nanokelvin range -- that's a full, what, 12 or 13 orders of magnitude too low in thermal energy to overcome the Coulomb potential keeping the nuclei apart. BEC's are notoriously tricky to create; you need to go through several cooling stages involving precisely tuned ultrastable lasers, and at the end of all that work, you get a ball of maybe a few billion atoms. It is simply not feasible to produce BEC's at any larger scale, nor to keep them condensed at fusion temperatures.
And as stupendous magnetic fields go, well, the best anyone can do right now is a sustained field of about 25 Tesla. I don't know offhand what fields they use in Tokamak experiments, but I'm betting it's no more than 10 Tesla, nor less than 1. Either way, there is no way we know of to make steady-state magnetic fields "many orders of magnitude stronger."
It's late now, and I'm getting tired, but suffice it to say that there's a lot more to be done than just making everything bigger. The energy scales are enormous, nobody really knows how to keep a plasma hot and contained, and it's going to take a lot more R&D before we can get usable energy out of fusion.
OK, lots of people have read "Prey" or one of the other Shiny! Exciting! Books! that talk about the "Gray Goo problem". Simply stated, this is that nanoassemblers which are trained to self-replicate could potentially go bonkers and start turning the entire planet into more assemblers. As Homestar Runner might put it, "That's just ridiculous" -- and yet this is what some people lose sleep over! The reason that nanoassemblers will never be able to replicate in an uncontrolled environment, and therefore will never take over the world, is that they need energy to function. Lots of it. Breaking pi and sigma bonds can be ridiculously expensive, requiring several eV of energy in some systems. Pulling a carbon out of a single-walled nanotube takes over 10 eV. Where does the energy come from? Absent a large and complex digestive system, the assemblers will have to be fueled ahead of time or provided with a simple energy source along with their raw materials. These robots will not be able to find the energy they need to keep going in the wild. That's why Smalley's not worried about runaway nanobots. The extreme difficulty of doing "machine-phase chemistry" is another good reason, by the way -- assuming machine-phase chemistry is even possible, how are the nanobots supposed to create a clean enough environment to do their work in the wild? If machine-phase chemistry can be accomplished at all, it will be a much more complicated affair, I think, than Drexler would have us believe.
What obscure constants?
Physics in the US is uniformly taught in SI units at the high school/university levels, at least to start; if you're referring to "obscure constants" like epsilon-nought, well, those exist because SI uses units that are convenient for everyday electromagnetic measurements (mostly; Tesla and Farad are the two big stinkers there, but Volts and Amps are nice).
You get rid of the obscure constants by switching to cgs units, at the cost of having to use statvolts, which are absurdly large. Take it one step further with "natural units" or "space-time units," in which the speed of light is 1.
My point is, the obscure constants kids have to deal with in physics are not a result of the US system of measurement.
I've read the paper 3 or 4 times, and I honestly have no idea what they're claiming. The paper itself is pretty opaque, and it's not at all clear whether they're talking about a real monopole or some sort of k-space mathematical artifact that just smells like one.
For those who don't have access to the article, these guys are making measurements on the anomalous Hall effect in a strontium ruthenate crystal. As far as I can tell, they are claiming that the fact that the transverse magnetoresistance is nonmonotonic with temperature implies an anomaly in the Berry phase of the electrons, hence a singularity in the vector potential and a magnetic monopole.
All this is in the first page. The actual discussion is thoroughly convoluted, and none of the CM faculty here seem to have a clue as to what the paper actually says. My guess is that they're just talking about something that looks like a monopole, but it's hard to say just from reading the paper.
Maybe they've figured out how to do large-scale imprint lithography, and are planning on scaling down to 50nm or 30nm.
But it's more likely that it's all just marketing.
Well, most students nationwide may have cell phones, but I'd say less than 10 percent of Dartmouth students do. For one thing, the reception is spotty at best, and I think only AT&T serves Hanover. For another, campus e-mail use is phenomenally high -- everyone uses Dartmouth's BlitzMail system, which works kind of like IMAP in that messages are stored centrally and you can get to them from any computer on campus (in fact, public computers are often referred to as "Blitz terminals.") You can even order pizza, Chinese, and all the other delivery options in town online -- so really the only use for a phone at Dartmouth is to call businesses (see who sells CO2 for your kegerator) or to call home. Dartmouth just made calling home free, which you have to admit is pretty nice.
As an aside, I disagree strongly that it is a waste of resources to have voice capabilities in dorms. In most cases, the wiring is already there, so it's a sunk cost -- might as well use it. When you're building new dorms, the marginal cost of adding phone wiring is minimal, so you might as well do it. Additionally, the capabilities have to be there for emergency services. Finally, there are plenty of people out there (myself included) who just don't have 500 bucks a year to spend on a cellular calling plan. All in all, it's definitely not a waste to keep phones in the dorms.
(Dartmouth '03, BTW, so I know what I'm talking about wrt campus phone use)
This is true... I need to be more careful posting late at night. The issue is that if an A record exists, the nameserver does not return NXDOMAIN. Since the spam filters look for an NXDOMAIN response, they are broken.
This will break sites like .museum, but it will mean my spam filtering works again.
.museum (which was chartered with a wildcard) and .de (which serves actual zone data from the .de root) from root-delegation-only.
It's worth noting that the latest ISC patch for BIND 9 supports excluding TLD's like
So you can have your cake and eat it too in this case.