No, I stay at my home institution unless I have shift or results to be blessed or the like. My wife is tied to the university, so we couldn't move out there.
The failures, or rather misdesigns/misbuilds, are in "copper bus bars". These effectively act as shorts across the superconducting electromagnet coils. Since the coils are normally superconducting (when at cryogenic temperatures), the short does nothing. But if the coil gets ever so slightly above its critical temperature, it ceases to be superconducting. At that point, it still has very very low resistance, but the current through it is so enormous that it heats up rapidly. When it gets to a certain temperature, its resistance becomes comparable to the resistance of the copper bus bar shorting it, and the current starts to flow more and more through the copper, thus protecting the superconductor from getting too much hotter. At least, that's what is supposed to happen.
What is wrong is that some of the solder joints for the bus bars are not good, and have too high of a resistance. A higher resistance in the bus bar system means a higher superconductor temperature before the current starts to flow through the copper, and in the end, this means damage to magnets.
I'm not sure what level of testing was done, but building a short segment and testing it up to slightly above design spec is probably not really feasible. In order to get the particles to the eventual energies, you need the whole ring to be in working order, because it takes tons of complete circles around the ring to accelerate the particles. Injection from the SPS to the LHC occurs at 1/14th the design beam energy, and the LHC ring takes it up from there.
Even if you could inject 7 TeV protons into a short segment of the ring, you'd still not be able to get the design beam intensity that way, because you don't have all 2000+ bunches ready for injection at once.
You could run the magnet intensities up to what is needed to bend a beam in a tight enough circle at high enough energies even without any actual beam in there, and this was probably done. However, quenches (magnets getting above critical temp) happen principally because of the beam. The beam loses particles and energy at a fairly high rate due to a variety of effects, and all those particles and all that energy goes into heating something, usually the bending magnets. I suppose you could do a deliberate quench by playing with the cryo, though. Perhaps that was done, and we were unfortunate enough to have tested only good subsystems this way.
As you may have guessed, I am a particle physicist (on CDF), but not a beams engineer. So, some of the above is guesswork, but I hope I've been able to relieve some of your ignorance.
Cross sections for most interesting processes go up with a large power of E (~6) at a hadron collider. This is largely due to the gluon parton distribution functions: as you go to higher proton energies, you need smaller and smaller fractions of the proton energy for heavy particle production, and at small fractions of the proton energy, there are gillions of gluons. This has the additional interesting effect that heavy particles are primarily produced at rest, because the less of the proton's energy you use (and therefore less kinetic energy for the produced heavy particle), the more gluons are available to contribute to the cross section.
I sure as hell hope you aren't "performance driving" on any road I'm on. If you want to do this for sport on a private track, fine, but don't endanger the lives of those (non-consenting) around you just to get a thrill.
FWIW, and I'm not enough of an economist or political scientist to evaluate what real impact this has on this discussion, Tesla Motors filed for IPO on Friday. They're hoping to raise hundreds of millions of dollar from private parties willing to risk their own money. Of course, why they didn't do this earlier, or perhaps instead of accepting the government loan, is not really within my grasp for the aforementioned reasons.
Well, it seems like you would figure that out on a case by case basis, by doing a fairly simple cost comparison after observing or estimating your typical usage patterns. If it turns out that it costs you more to rent a truck when you need it than to own a truck, then buy the truck. Otherwise, rent the truck. Is that so hard?
It might not make sense for you, but it probably makes sense for someone else, or the idea wouldn't have been brought up in discussion here. For instance, it makes sense for me. I make two long car trips each year, and renting for those two trips would almost certainly cost less than paying for a second car, or paying for gas and increased maintenance costs on my driving-around-the-city car.
If it doesn't make sense for you, then don't do it. But don't knock it when it might help out a whole lot of other people who live in different situations.
It is already a tradeoff between the real estate cost of living in the city and the fuel cost of living in the country (among a very very wide variety of other differences between the city and country...). The development of viable electric cars would simply reduce the fuel cost of living in the city, even though that is already fairly low. Of course, it would also likely reduce the maintenance costs of vehicle ownership in the city, and reduce the health costs of living in the city.
Yes, this would principally benefit city dwellers over country dwellers. But you know, there are a lot of people that live in cities. Maybe something that is of benefit to them is worthwhile, especially if it doesn't hurt people who don't live in cities.
Slow down, cowboy! (see what I did there?;) Nobody in this discussion is looking to prevent you from driving whatever you like, living wherever you like, or living however you like. Let's recap.
An AC said that we need Tesla to prove that electric vehicles are a viable alternative to gasoline vehicles. Another (presumably not the same..) AC said that EVs are not a viable alternative because they either cost too much or have too small of a range. Then obarthelemy cited a study and claimed that the study indicates that range is not actually that important, and that we should mostly worry about the economics and practicality of a particular vehicular usage scheme.
Where in this is obarthelemy, or anyone else, denying or attempting to deny you the freedom to choose your lifestyle? If you don't feel that EVs are viable for you, then don't use them! Do you feel that the presence of alternatives is a threat to your lifestyle? If not, then you should absolutely support the development of alternatives for a variety of reasons that should be pretty obvious.
A quick googling ("libgmp.net mono") turns up the possibility that there may be a wrapper for libgmp in mono. Other than my google-fu, I know nothing of.net and mono.
You might also prefer LabView, for visual arrangement of calculation and even programming flow. I didn't particularly like it for some specific technical reasons, but I can see where someone as visually oriented as you say you are might really benefit from it.
The key to your undoing is in your first sentence. You are clearly aware of Shannon entropy or information. The universe contains a certain amount of information, regardless of the amount of data you use to describe that information. You cannot simulate X amount of information while only using Y information X. So, the only in-the-universe computer capable of simulating the entire universe exactly is the universe.
And the voting public in Massachusets (Masschusets for crying out loud!) just threw a Democrat out on his ass. Screwed indeed. Nobody likes anybody, regardless of party. Can we move on back to the topic yet?
You might say that these companies have discovered that there is significant value (enough to pay some developers) in the existence/availability of good code, even if they do not derive any value from the sale of that code.
And your high powered gaming-class PC would be bigger, louder, draw more power from the wall, and potentially wouldn't fulfill the "everything must be Free" design specification. In short, it would fail at almost everything that the designers of this machine considered to be attractive design features. On a related note, I could also buy a washing machine or a whole beowulf cluster of toasters for the same cost as "that thing". This is about as relevant to TFA as your gaming PC.
According to the Federal Register (PDF), an Emergency OMB Review was requested to launch the joint initiative of the DOL, White House, and IdeaScale to help out unemployed US workers.
We're going to help out unemployed US workers... by shipping them to India and paying them peanuts, *at best*. Chances are that what will happen is that no sane US worker, unemployed and desperate or not, will take this, and we will be sending our tax money to India to go into the pockets of Indian workers. Now, I don't have any sort of moral outrage at this, except for the fact that it is being done in the name of helping out unemployed US workers, which it will not accomplish in any significant way.
It all depends on your problem domain. As a high energy physicist, I write plenty of code that me, a postdoc, and maybe a couple other grad students will ever see, and probably I'm the only one that will actually ever use it. I'm designing a small cluster that will get built here in a month or few, and some of my code will take up about 2 months of solid run time on it, then never see the light of day again. If I can spend 2 days getting a 5% performance improvement, even at the expense of locking the code to this cluster, it's a net win for us.
In short, I have no "customers", I know exactly what hardware my code will be running on, and it won't ever change (until they ditch the cluster in 4-5 years and make a new one, but I'll be long gone), and I don't even have to worry about maintaining the code years in the future.
All the same, I'll probably still write the code as cleanly as possible and run it through an optimizer, and leave it at that.
It's over IP, you said? Configure your laptop to claim over IP that it got the SysRq keystroke. If its over IP, then you almost certainly have a software layer between your laptop keyboard and the remote KVM. Change the software accordingly, or don't buy this laptop. At least one of these options is not difficult.
Look up the mathematical definition of flux (integrate the scalar product of the vector field with the differential area vector normal to the surface). You and the GP are saying two different things. The GP is correct, and you are not, although I think you have the right idea, just the wrong words. The change (over time) of the magnetic flux (think "the amount of magnetic field") passing through a conducting loop is proportional to the current generated around the loop.
I am not attempting to engage you in debate about the relative merits of nuclear electricity generation vs. any other mechanism for generating electricity. This is as I said in my original post. Nor am I interested in engaging you in said debate. I am interested in the debate, as it likely has significant consequences for the long term future of the human race, but I am deliberately refraining from entering the fray so as to be able to point out what I consider, as I said, gross hypocrisy on the part of one debater: you. I'm quite happy for you that you feel confident in your level of experience, but I neither know nor care at the moment what that level of experience is, nor even that you have it. In fact, the entire topic of debate is completely irrelevant to my point. For all that it matters, this could be a debate about whether to open eggs at the big end or the little end.
That said, I still maintain that it is highly inappropriate to open what you implicitly claim is a carefully reasoned, polite, fact checked, and well informed post with a string of ad hominem attacks on your opposition (which is certainly not polite, has no relationship to any relevant facts, and involves no reasoning or well-informedness), followed by a denouncement of ad hominem attacks by your opposition. *You at once use a weapon and condemn its use.* This is your hypocrisy. The validity, real or imagined, of your ad hominem attacks does not change it in the slightest degree.
If you produced the attacks, but did not condemn them, then you would be merely unpleasant, not a hypocrit. Similarly, if you condemned ad hominem attacks, but did not make any of your own, you would not be a hypocrit. The combination, however, is damning, and it is against the combination that I am complaining.
If I am on the pro-nuclear side, then naturally I would want to discredit you as an opponent, by pointing out your ad hominem attacks and hypocrisy if necessary. If I am perfectly disinterested, then naturally I would want to discredit you, if only to discourage others from writing such unpleasant posts in the future. If I am on the anti-nuclear side, then naturally I would want to discredit you, as your vitriol and hypocrisy are actually detrimental to the anti-nuclear side of the debate.
So you see, regardless of my position, I would be inclined to censure you, even as I am now doing.
Most of the Nuclear supporters here have a rabid fanboi attitude which puts the in the realm of Dogmatic Skeptics.
Once their belief systems are challenged they resort to ad-hominem attacks as I'm sure you have experienced.
Well, the old hypocrisy acting up these days, MrKaos? I'm not even going to bother to mention which side of this debate I sit on, since it is utterly irrelevant to my point, and I am not even attempting to participate in the debate with this post. The juxtaposition of those two sentences just threw up all kinds of red flags, and I felt something had to be said.
Beta particles are emitted with a very wide range of energies. The difference between the binding energy of the emitting nucleus and the resulting nucleus is the maximum energy that the beta particle can carry, but in addition to the beta particle, the nucleus emits an electron antineutrino, which carries a significant fraction of the energy itself. Typical beta emitters have a maximum beta particle energy around 1 MeV (equivalent to putting an electron near an electrode that was at 1 million volts, and then getting hit with it when standing near the ground at zero volts.). Tritium has a max beta energy of 18.6 keV (change 1 million volts above to 18600 volts), which is much much lower. I'd say that two orders of magnitude lower than typical is certainly enough to be called "low energy". This energy is actually below the ionization energy of a decent number (although probably not the majority) of molecules. Furthermore, the rate of energy loss to surrounding material (attenuation) varies with particle energy, and at very low energies, it increases very rapidly. So an 18.6 keV electron will not travel very far in air, and will typically not penetrate the first layer of your skin, which is dead and therefore not a cancer risk anyway. The GP was correct: beta particles from tritium are highly atypical, and in a manner which makes them much less dangerous than other beta radiation. I am a particle physicist, and I approve this message.
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No, I stay at my home institution unless I have shift or results to be blessed or the like. My wife is tied to the university, so we couldn't move out there.
The failures, or rather misdesigns/misbuilds, are in "copper bus bars". These effectively act as shorts across the superconducting electromagnet coils. Since the coils are normally superconducting (when at cryogenic temperatures), the short does nothing. But if the coil gets ever so slightly above its critical temperature, it ceases to be superconducting. At that point, it still has very very low resistance, but the current through it is so enormous that it heats up rapidly. When it gets to a certain temperature, its resistance becomes comparable to the resistance of the copper bus bar shorting it, and the current starts to flow more and more through the copper, thus protecting the superconductor from getting too much hotter. At least, that's what is supposed to happen.
What is wrong is that some of the solder joints for the bus bars are not good, and have too high of a resistance. A higher resistance in the bus bar system means a higher superconductor temperature before the current starts to flow through the copper, and in the end, this means damage to magnets.
I'm not sure what level of testing was done, but building a short segment and testing it up to slightly above design spec is probably not really feasible. In order to get the particles to the eventual energies, you need the whole ring to be in working order, because it takes tons of complete circles around the ring to accelerate the particles. Injection from the SPS to the LHC occurs at 1/14th the design beam energy, and the LHC ring takes it up from there.
Even if you could inject 7 TeV protons into a short segment of the ring, you'd still not be able to get the design beam intensity that way, because you don't have all 2000+ bunches ready for injection at once.
You could run the magnet intensities up to what is needed to bend a beam in a tight enough circle at high enough energies even without any actual beam in there, and this was probably done. However, quenches (magnets getting above critical temp) happen principally because of the beam. The beam loses particles and energy at a fairly high rate due to a variety of effects, and all those particles and all that energy goes into heating something, usually the bending magnets. I suppose you could do a deliberate quench by playing with the cryo, though. Perhaps that was done, and we were unfortunate enough to have tested only good subsystems this way.
As you may have guessed, I am a particle physicist (on CDF), but not a beams engineer. So, some of the above is guesswork, but I hope I've been able to relieve some of your ignorance.
Cross sections for most interesting processes go up with a large power of E (~6) at a hadron collider. This is largely due to the gluon parton distribution functions: as you go to higher proton energies, you need smaller and smaller fractions of the proton energy for heavy particle production, and at small fractions of the proton energy, there are gillions of gluons. This has the additional interesting effect that heavy particles are primarily produced at rest, because the less of the proton's energy you use (and therefore less kinetic energy for the produced heavy particle), the more gluons are available to contribute to the cross section.
I sure as hell hope you aren't "performance driving" on any road I'm on. If you want to do this for sport on a private track, fine, but don't endanger the lives of those (non-consenting) around you just to get a thrill.
FWIW, and I'm not enough of an economist or political scientist to evaluate what real impact this has on this discussion, Tesla Motors filed for IPO on Friday. They're hoping to raise hundreds of millions of dollar from private parties willing to risk their own money. Of course, why they didn't do this earlier, or perhaps instead of accepting the government loan, is not really within my grasp for the aforementioned reasons.
Well, it seems like you would figure that out on a case by case basis, by doing a fairly simple cost comparison after observing or estimating your typical usage patterns. If it turns out that it costs you more to rent a truck when you need it than to own a truck, then buy the truck. Otherwise, rent the truck. Is that so hard?
It might not make sense for you, but it probably makes sense for someone else, or the idea wouldn't have been brought up in discussion here. For instance, it makes sense for me. I make two long car trips each year, and renting for those two trips would almost certainly cost less than paying for a second car, or paying for gas and increased maintenance costs on my driving-around-the-city car.
If it doesn't make sense for you, then don't do it. But don't knock it when it might help out a whole lot of other people who live in different situations.
Yes, this would principally benefit city dwellers over country dwellers. But you know, there are a lot of people that live in cities. Maybe something that is of benefit to them is worthwhile, especially if it doesn't hurt people who don't live in cities.
Slow down, cowboy! (see what I did there? ;) Nobody in this discussion is looking to prevent you from driving whatever you like, living wherever you like, or living however you like. Let's recap.
An AC said that we need Tesla to prove that electric vehicles are a viable alternative to gasoline vehicles. Another (presumably not the same..) AC said that EVs are not a viable alternative because they either cost too much or have too small of a range. Then obarthelemy cited a study and claimed that the study indicates that range is not actually that important, and that we should mostly worry about the economics and practicality of a particular vehicular usage scheme.
Where in this is obarthelemy, or anyone else, denying or attempting to deny you the freedom to choose your lifestyle? If you don't feel that EVs are viable for you, then don't use them! Do you feel that the presence of alternatives is a threat to your lifestyle? If not, then you should absolutely support the development of alternatives for a variety of reasons that should be pretty obvious.
A quick googling ("libgmp .net mono") turns up the possibility that there may be a wrapper for libgmp in mono. Other than my google-fu, I know nothing of .net and mono.
You might also prefer LabView, for visual arrangement of calculation and even programming flow. I didn't particularly like it for some specific technical reasons, but I can see where someone as visually oriented as you say you are might really benefit from it.
All we had was sets. And if we complained, von Neumann came and beat us with his curly braces!
The key to your undoing is in your first sentence. You are clearly aware of Shannon entropy or information. The universe contains a certain amount of information, regardless of the amount of data you use to describe that information. You cannot simulate X amount of information while only using Y information X. So, the only in-the-universe computer capable of simulating the entire universe exactly is the universe.
Play the violin, Johnny!
And the voting public in Massachusets (Masschusets for crying out loud!) just threw a Democrat out on his ass. Screwed indeed. Nobody likes anybody, regardless of party. Can we move on back to the topic yet?
Fourthed. Widely used, and very effective, in the physics community.
You might say that these companies have discovered that there is significant value (enough to pay some developers) in the existence/availability of good code, even if they do not derive any value from the sale of that code.
And your high powered gaming-class PC would be bigger, louder, draw more power from the wall, and potentially wouldn't fulfill the "everything must be Free" design specification. In short, it would fail at almost everything that the designers of this machine considered to be attractive design features. On a related note, I could also buy a washing machine or a whole beowulf cluster of toasters for the same cost as "that thing". This is about as relevant to TFA as your gaming PC.
According to the Federal Register (PDF), an Emergency OMB Review was requested to launch the joint initiative of the DOL, White House, and IdeaScale to help out unemployed US workers.
We're going to help out unemployed US workers... by shipping them to India and paying them peanuts, *at best*. Chances are that what will happen is that no sane US worker, unemployed and desperate or not, will take this, and we will be sending our tax money to India to go into the pockets of Indian workers. Now, I don't have any sort of moral outrage at this, except for the fact that it is being done in the name of helping out unemployed US workers, which it will not accomplish in any significant way.
It all depends on your problem domain. As a high energy physicist, I write plenty of code that me, a postdoc, and maybe a couple other grad students will ever see, and probably I'm the only one that will actually ever use it. I'm designing a small cluster that will get built here in a month or few, and some of my code will take up about 2 months of solid run time on it, then never see the light of day again. If I can spend 2 days getting a 5% performance improvement, even at the expense of locking the code to this cluster, it's a net win for us.
In short, I have no "customers", I know exactly what hardware my code will be running on, and it won't ever change (until they ditch the cluster in 4-5 years and make a new one, but I'll be long gone), and I don't even have to worry about maintaining the code years in the future.
All the same, I'll probably still write the code as cleanly as possible and run it through an optimizer, and leave it at that.
It's over IP, you said? Configure your laptop to claim over IP that it got the SysRq keystroke. If its over IP, then you almost certainly have a software layer between your laptop keyboard and the remote KVM. Change the software accordingly, or don't buy this laptop. At least one of these options is not difficult.
Look up the mathematical definition of flux (integrate the scalar product of the vector field with the differential area vector normal to the surface). You and the GP are saying two different things. The GP is correct, and you are not, although I think you have the right idea, just the wrong words. The change (over time) of the magnetic flux (think "the amount of magnetic field") passing through a conducting loop is proportional to the current generated around the loop.
I am not attempting to engage you in debate about the relative merits of nuclear electricity generation vs. any other mechanism for generating electricity. This is as I said in my original post. Nor am I interested in engaging you in said debate. I am interested in the debate, as it likely has significant consequences for the long term future of the human race, but I am deliberately refraining from entering the fray so as to be able to point out what I consider, as I said, gross hypocrisy on the part of one debater: you. I'm quite happy for you that you feel confident in your level of experience, but I neither know nor care at the moment what that level of experience is, nor even that you have it. In fact, the entire topic of debate is completely irrelevant to my point. For all that it matters, this could be a debate about whether to open eggs at the big end or the little end.
That said, I still maintain that it is highly inappropriate to open what you implicitly claim is a carefully reasoned, polite, fact checked, and well informed post with a string of ad hominem attacks on your opposition (which is certainly not polite, has no relationship to any relevant facts, and involves no reasoning or well-informedness), followed by a denouncement of ad hominem attacks by your opposition. *You at once use a weapon and condemn its use.* This is your hypocrisy. The validity, real or imagined, of your ad hominem attacks does not change it in the slightest degree.
If you produced the attacks, but did not condemn them, then you would be merely unpleasant, not a hypocrit. Similarly, if you condemned ad hominem attacks, but did not make any of your own, you would not be a hypocrit. The combination, however, is damning, and it is against the combination that I am complaining.
If I am on the pro-nuclear side, then naturally I would want to discredit you as an opponent, by pointing out your ad hominem attacks and hypocrisy if necessary. If I am perfectly disinterested, then naturally I would want to discredit you, if only to discourage others from writing such unpleasant posts in the future. If I am on the anti-nuclear side, then naturally I would want to discredit you, as your vitriol and hypocrisy are actually detrimental to the anti-nuclear side of the debate.
So you see, regardless of my position, I would be inclined to censure you, even as I am now doing.
Most of the Nuclear supporters here have a rabid fanboi attitude which puts the in the realm of Dogmatic Skeptics.
Once their belief systems are challenged they resort to ad-hominem attacks as I'm sure you have experienced.
Well, the old hypocrisy acting up these days, MrKaos? I'm not even going to bother to mention which side of this debate I sit on, since it is utterly irrelevant to my point, and I am not even attempting to participate in the debate with this post. The juxtaposition of those two sentences just threw up all kinds of red flags, and I felt something had to be said.
This ain't right.
Beta particles are emitted with a very wide range of energies. The difference between the binding energy of the emitting nucleus and the resulting nucleus is the maximum energy that the beta particle can carry, but in addition to the beta particle, the nucleus emits an electron antineutrino, which carries a significant fraction of the energy itself. Typical beta emitters have a maximum beta particle energy around 1 MeV (equivalent to putting an electron near an electrode that was at 1 million volts, and then getting hit with it when standing near the ground at zero volts.). Tritium has a max beta energy of 18.6 keV (change 1 million volts above to 18600 volts), which is much much lower. I'd say that two orders of magnitude lower than typical is certainly enough to be called "low energy". This energy is actually below the ionization energy of a decent number (although probably not the majority) of molecules. Furthermore, the rate of energy loss to surrounding material (attenuation) varies with particle energy, and at very low energies, it increases very rapidly. So an 18.6 keV electron will not travel very far in air, and will typically not penetrate the first layer of your skin, which is dead and therefore not a cancer risk anyway. The GP was correct: beta particles from tritium are highly atypical, and in a manner which makes them much less dangerous than other beta radiation. I am a particle physicist, and I approve this message.