What you say is very reasonable, but I think it is a bit naive to assume that the laws will be applied in such a reasonable manner. From what I've seen, enforcement of OSHA regulations tends to be very much in the letter-of-the-law spirit. That may decrease the amount of injuries in the long run, but it's certainly an inefficient and obnoxious way to go. There's no a priori reason to suspect that the regulations will be any more well thought out for the long-run than companies' current policies are.
AFAIK (I'm not a fusion expert) fusion is easier to do if you fuse deuterium and tritium, and that reaction does indeed give off a neutron: 2H + 3H -> 5He -> 4He + 1n (or something very similar to that).
As for making deuterium with fission reactors, most fission reactors are surrounded by water, but hydrogen has such a low neutron capture cross section you don't get any significant quantity of deuterium (If hydrogen did have a large capture cross section, you wouldn't want to surround a reactor with it because it would soak up all the neutrons, upon which the fission chain reaction depends). I work at a research reactor; it's a 250kW reactor sitting at the bottom of a 25ft deep pool of water. That water's been there for 30 years (reactor was installed in 1968), and it's still just regular old water:)
Right, but the advantage to fusion is that it's basically just the reactor itself that's radioactive; you don't dispose of reactors very often. I would guess that a typical (heh...) fusion power plant would generate within an order of magnitude as much low-level waste as a fission-based plant, but very little high-level waste.
It really sucks that groff isn't y2k-ready. I'm curious as to how it fails--if it stops working altogether (unlikely, I presume) then nobody will be able to read man pages.... If it just screws up and gets the date wrong when you tell it to print the date, that's kind of annoying but hardly serious.
It would be nice if they had more detailed descriptions of the problems with the 'not ready' stuff.
I have no particular love for ISA, but the one thing it's basically necessary for is modems. It's damn near impossible to find a PCI non-winmodem. Modem manufacturers need to remedy this, but I doubt it's going to happen anytime soon--the marketing advantages are too great. People who know enough not to buy winmodems are probably aware that a PCI modem is no fster or bettr than an ISA modem, but there are plenty of clueless people out there that think that a cheap PCI winmodem sounds like a great deal...
I don't think you can necessarily say quantum computers will "kill public-key cryptography forever". Even if, 10 years from now, it's possible to build a device for, say, $1e6 that can quickly break RSA, I'd still feel comfortable using ssh RSA authentication to protect my computer, because nobody in their right mind would go to that kind of effort to break into my machine. Public key crypto is just too damn useful to disappear anytime soon, and you can bet that significant effort will be applied to keep it viable. Quantum computers of that ability are far enough off that it's not unlikely that public-key algorithms that are resistant to such methods will be developed by the time RSA or El-Gamal are broken.
Here at school we've got all sorts of naming conventions. Most of our "real" servers are named after ancient egyptian gods (eg amon, osiris, isis, anubis, etc). The math professors' Suns are one, two, three, etc. The chem SGIs are all named after elements. And so on. Having a coherent naming scheme is not only fun but useful: when a user says something like "I can't log into krypton" I at least know what I'm dealing with (IRIX, in this case). Using names like sparcstationnumber234 isn't just obnoxious, it's an organizational mess despite the effort to the contrary.
The Zippy filter is still around. For anyone who hasn't seen it, you should really check it out. It's just about the funniest thing on the web: http://www.metahtml.com/apps/zippy/welcome.mhtml
I changed to to do a frequency count for each number mod 26:
$./freq 038-097-34-64-242-335-51-377-183-168 038-097-34-64-380-330-115-289-273-189-56 068-486-42-23-87-434-10-468-151-345-150-494-376-41 5-426 038-549-53-15-1-193-121-29-109-66-28-160-106 047-111-70-99-24-21-25-12-53-22-56-8 results ------- Number of 0 is 2 Number of 1 is 4 Number of 2 is 2 Number of 3 is 3 Number of 4 is 3 Number of 5 is 1 Number of 7 is 3 Number of 8 is 4 Number of 9 is 1 Number of 10 is 2 Number of 11 is 2 Number of 12 is 8 Number of 13 is 2 Number of 14 is 1 Number of 15 is 1 Number of 16 is 3 Number of 17 is 1 Number of 18 is 4 Number of 19 is 2 Number of 20 is 1 Number of 21 is 4 Number of 22 is 1 Number of 23 is 2 Number of 24 is 1 Number of 25 is 3
Examples include: Prodigy-Experience Moby-Moby and the Next is the E remixes 808 State-Gorgeous or ex:el Lords of Acid-Lust Altern8-anything (has anyone but me ever heard of these guys?) Messiah-21st Century Jesus The compilations _Rave til Dawn_ and _Aural Ecstasy_ are good too. There's surely stuff that I've forgotten over the years...
From my handy Quantum Mechanics textbook: "In 1977 Misra and Sudarshan proposed what they call the quantum Zeno effect as a dramatic experimental demonstration of the collapse of the wave function. Their idea was to take an unstable system (an atom in an excited state, say) and subject it to repeated measurements. Each observation collapses the wave function, resetting the clock, and it is possible by this means to delay indefinitely the expected transition to the lower state.... As it turns out, the experiment is impractical for spontaneous transitions, but it can be done using induced transitions, and the results are in excellent agreement with theoretical predictions."
_Introduction to Quantum Mechanics_, David Griffiths, pp. 383-4
It works like this: Uranium (even highly enriched in U235--the fissile isotope) has a very long half life and thus isn't very radioactive. From a radiation standpoint, it's not too difficult to handle. I operate a nuclear research reactor, and I have held new fuel elements in my hands. Anyway, the way nuclear fission works is that a neutron hits a U235 atom and it splits apart into two lighter fragments and releases on average 2.4 neutrons, and also lots of energy and radiation. These neutrons then go off and start other fission reactions -- a self-sustaining chain reaction. There are many factors that control whether the reaction is self-sustaining, such as the amount of U235 present, geometry (a tight sphere will react more readily than a bunch of spread-out lumps), moderation, etc. Sub-critical means the reaction isn't self-sustaining. This is the "normal" state of things (there are always fissions happening, but at a very low level). Critical means it is exactly self-sustaining. It means a steady state. Supercritical means it's more than self-sustaining -- the rate of reaction is increasing. Anyway, criticality accidents have happened all too many times before. The usual result is that the people who were initially exposed die of massive radiation exposure, but it's probably not much of a danger to people beyond that. This is entirely different from a "meltdown" or "China Syndrome" accident. Criticality accidents are usually (I think) caused by a change in geomerty that wasn't supposed to happen. I remember hearing about one in which fissile material mistakenly made it into a centrifuge. It was sitting at the bottom of the centrifuge in a subcritical geometry. When they turned it on, it got flung up against the walls of the container, and for a brief instant passed through a supercritical geometry and then went subcritical again. Of course, this killed the operator of the centrifuge. When they sent people in to investigate, one of the things they did was to turn off the centrifuge (since nobody who witnessed the accident was alive, they didn't really know what had happened). Of course, this caused it to go critical again for a brief moment, severely injuring the rescue party.
Their SuSE box is somewhat more usefully set up than the others. The RedHat box seems to not allow outgoing network connections. Bah. The tru64 box doesn't have any kind of sane bash environment set up and has no X clients installed. The SuSE box allows outgoing network connections (I have an xterm open on it) and even has ssh installed! By the way, be careful typing those IP addresses... I got the wrong one by mistake and in place of a login I got something like "This is not a public machine. Your attempt to connect has been logged."
I don't know about other nameservers, but BIND has support for the AAAA record, which is like an A record but for an ipv6 address. So if you're using a recent version of BIND, you can have it serve up ipv4 and ipv6 addresses for the same name, depending on what the resolver asks for.
I wrote a silly cgi script to do the same thing last year. Didn't think it worthy of being on slashdot. It's not quite as cool, but it does do.com.org and.net.
You sort of got the lead part backwards:) Lead stops gammas perfectly well. You have to be careful when using lead to shield betas, because you get bremstrahllung (sp?) X-rays. Compact neutron shielding is the hardest one. You first have to thermalize any fast neutrons (with water or some kind of plastic with lots of hydrogen, for the reasons you described), then surround that with a neutron absorber (e.g. boron or cadmium), but _that_ produces gammas (and alphas also in the case of boron), which have to further be shielded by, e.g. lead.
But they're looking at neutrinos, not neutrons anyway.
I installed linuxPPC on somebody's iMac earlier this year at an installfest. There's some real perverse pleasure in making those silly things boot Unix:) After some initial difficulties (which I don't remember too well) the install went quite smoothly, even getting X running. The mouse worked fine, so I guess the USB support is decent. However, upon starting X, the keyboard sort of stopped working--it was like it got remapped randomly. That was fun. I never heard back from him, but I would assume that something like that would be fixed by now...
The patent you refer to was claimed by PKP to cover all of PK crypto, but it expired before it ever got tested in court (1997, IIRC). So it's all good. And the RSA patent expires in about a year.
I you use a suitably strong public key algorithm and a cryptographically strong hash function (both of which are very easily available) you can generate a digital signature which can't be manipulated. See the README distributed with PGP for details.
He makes a very valid point about TMI: nobody was hurt. The outcome of the TMI accident is a great testament to the good design of American power reactors. If the same thing had happened to, say, a Russian RBMK reactor, it would have been another Chernobyl, no question. You can't expect anything nearly as complicated as a power reactor to go for decades in hundreds of installations across the country without having problems; but the fact that they have done so without harming *people* shows how reliable the system is. Regardless of how underhanded a utility company may be, the NRC is pervasive and persistent enough to keep them out of trouble. I've seen NRC inspections first hand, and those guys absolutely will not let anything slip by them. Popular paranoia about corruption goes to really extreme levels. I was talking with an NRC examiner the other day (I was taking a license exam) and he was telling me that when they visit a power plant for inspection, they have to go to ridiculous extremes to avoid being seen in public with any plant personnel, because people from "watchdog groups" follow them around and publicly accuse them of being in the plant officials' pocket if they're seen together.
The entire bit about terrorists is bogus. First of all, nothing in a power reactor, or just about any other reactor for that matter, is of any use to terrorists. The fuel is of a very low enrichment, and furthermore the plutonium produced by neutron activation of U238 contains too many other Pu isotopes to be of any use without doing isotope separation, which no terrorist organization is even remotely capable of doing. Not to mention that new fuel is immediately irradiated to make it impossible to remove from the facility without killing yourself. Bombing a power plant is also not a real threat. Power reactor containment structures are designed to withstand being directly hit by crashing jetliners. If a terrorist has weapons of similar power and is planning on using them, people should definitely be concerned about more than just the threat to power reactors. You also seem to misunderstand what the effects of bombing a reactor would be: it would be just like bombing any other building, except that if you succeeded in blowing it open you'd release radioactive material. There is absolutely *no* *way* you can make a reactor do anything like a nuclesar weapon. The worst-case scenario is much more akin to Chernobyl than to Hiroshima.
I think it would definitely suck to have these things everywhere, but my main concern would not be radiation, but privacy. I have no problems with them being in just airports. Not that I mean to defend this type of thing, but if they did become so pervasive the dose these things give you would have to be lowered first. Members of the public aren't allowed to be exposed to >100mRem per year, or >2mRem in an hour.
Higher altitude (less atmospheric shielding from cosmic rays), and the soil/rocks there contain more uranium than most other places (uranium itself is hardly radioactive, but radon is produced by its decay, and radon decays into a series of short-lived solids which hang out in your lungs).
Slashdot Mirror
What you say is very reasonable, but I think it is a bit naive to assume that the laws will be applied in such a reasonable manner. From what I've seen, enforcement of OSHA regulations tends to be very much in the letter-of-the-law spirit. That may decrease the amount of injuries in the long run, but it's certainly an inefficient and obnoxious way to go. There's no a priori reason to suspect that the regulations will be any more well thought out for the long-run than companies' current policies are.
AFAIK (I'm not a fusion expert) fusion is easier to do if you fuse deuterium and tritium, and that reaction does indeed give off a neutron: 2H + 3H -> 5He -> 4He + 1n (or something very similar to that).
:)
As for making deuterium with fission reactors, most fission reactors are surrounded by water, but hydrogen has such a low neutron capture cross section you don't get any significant quantity of deuterium (If hydrogen did have a large capture cross section, you wouldn't want to surround a reactor with it because it would soak up all the neutrons, upon which the fission chain reaction depends). I work at a research reactor; it's a 250kW reactor sitting at the bottom of a 25ft deep pool of water. That water's been there for 30 years (reactor was installed in 1968), and it's still just regular old water
Right, but the advantage to fusion is that it's basically just the reactor itself that's radioactive; you don't dispose of reactors very often. I would guess that a typical (heh...) fusion power plant would generate within an order of magnitude as much low-level waste as a fission-based plant, but very little high-level waste.
It really sucks that groff isn't y2k-ready. I'm curious as to how it fails--if it stops working altogether (unlikely, I presume) then nobody will be able to read man pages.... If it just screws up and gets the date wrong when you tell it to print the date, that's kind of annoying but hardly serious.
It would be nice if they had more detailed descriptions of the problems with the 'not ready' stuff.
I have no particular love for ISA, but the one thing it's basically necessary for is modems. It's damn near impossible to find a PCI non-winmodem. Modem manufacturers need to remedy this, but I doubt it's going to happen anytime soon--the marketing advantages are too great. People who know enough not to buy winmodems are probably aware that a PCI modem is no fster or bettr than an ISA modem, but there are plenty of clueless people out there that think that a cheap PCI winmodem sounds like a great deal...
I don't think you can necessarily say quantum computers will "kill public-key cryptography forever". Even if, 10 years from now, it's possible to build a device for, say, $1e6 that can quickly break RSA, I'd still feel comfortable using ssh RSA authentication to protect my computer, because nobody in their right mind would go to that kind of effort to break into my machine. Public key crypto is just too damn useful to disappear anytime soon, and you can bet that significant effort will be applied to keep it viable. Quantum computers of that ability are far enough off that it's not unlikely that public-key algorithms that are resistant to such methods will be developed by the time RSA or El-Gamal are broken.
Here at school we've got all sorts of naming conventions. Most of our "real" servers are named after ancient egyptian gods (eg amon, osiris, isis, anubis, etc). The math professors' Suns are one, two, three, etc. The chem SGIs are all named after elements. And so on.
Having a coherent naming scheme is not only fun but useful: when a user says something like "I can't log into krypton" I at least know what I'm dealing with (IRIX, in this case). Using names like sparcstationnumber234 isn't just obnoxious, it's an organizational mess despite the effort to the contrary.
The Zippy filter is still around. For anyone who hasn't seen it, you should really check it out. It's just about the funniest thing on the web: http://www.metahtml.com/apps/zippy /welcome.mhtml
I changed to to do a frequency count for each number mod 26:
./freq 1 5-426
$
038-097-34-64-242-335-51-377-183-168
038-097-34-64-380-330-115-289-273-189-56
068-486-42-23-87-434-10-468-151-345-150-494-376-4
038-549-53-15-1-193-121-29-109-66-28-160-106
047-111-70-99-24-21-25-12-53-22-56-8
results -------
Number of 0 is 2
Number of 1 is 4
Number of 2 is 2
Number of 3 is 3
Number of 4 is 3
Number of 5 is 1
Number of 7 is 3
Number of 8 is 4
Number of 9 is 1
Number of 10 is 2
Number of 11 is 2
Number of 12 is 8
Number of 13 is 2
Number of 14 is 1
Number of 15 is 1
Number of 16 is 3
Number of 17 is 1
Number of 18 is 4
Number of 19 is 2
Number of 20 is 1
Number of 21 is 4
Number of 22 is 1
Number of 23 is 2
Number of 24 is 1
Number of 25 is 3
Still doesn't look promising...
Examples include:
Prodigy-Experience
Moby-Moby and the Next is the E remixes
808 State-Gorgeous or ex:el
Lords of Acid-Lust
Altern8-anything (has anyone but me ever heard of these guys?)
Messiah-21st Century Jesus
The compilations _Rave til Dawn_ and _Aural Ecstasy_ are good too. There's surely stuff that I've forgotten over the years...
There's actually a footnote that says this is sometimes referred to as the Watched Pot Effect :)
From my handy Quantum Mechanics textbook: ... As it turns out, the experiment is impractical for spontaneous transitions, but it can be done using induced transitions, and the results are in excellent agreement with theoretical predictions."
"In 1977 Misra and Sudarshan proposed what they call the quantum Zeno effect as a dramatic experimental demonstration of the collapse of the wave function. Their idea was to take an unstable system (an atom in an excited state, say) and subject it to repeated measurements. Each observation collapses the wave function, resetting the clock, and it is possible by this means to delay indefinitely the expected transition to the lower state.
_Introduction to Quantum Mechanics_, David Griffiths, pp. 383-4
It works like this:
Uranium (even highly enriched in U235--the fissile isotope) has a very long half life and thus isn't very radioactive. From a radiation standpoint, it's not too difficult to handle. I operate a nuclear research reactor, and I have held new fuel elements in my hands. Anyway, the way nuclear fission works is that a neutron hits a U235 atom and it splits apart into two lighter fragments and releases on average 2.4 neutrons, and also lots of energy and radiation. These neutrons then go off and start other fission reactions -- a self-sustaining chain reaction. There are many factors that control whether the reaction is self-sustaining, such as the amount of U235 present, geometry (a tight sphere will react more readily than a bunch of spread-out lumps), moderation, etc. Sub-critical means the reaction isn't self-sustaining. This is the "normal" state of things (there are always fissions happening, but at a very low level). Critical means it is exactly self-sustaining. It means a steady state. Supercritical means it's more than self-sustaining -- the rate of reaction is increasing.
Anyway, criticality accidents have happened all too many times before. The usual result is that the people who were initially exposed die of massive radiation exposure, but it's probably not much of a danger to people beyond that. This is entirely different from a "meltdown" or "China Syndrome" accident. Criticality accidents are usually (I think) caused by a change in geomerty that wasn't supposed to happen. I remember hearing about one in which fissile material mistakenly made it into a centrifuge. It was sitting at the bottom of the centrifuge in a subcritical geometry. When they turned it on, it got flung up against the walls of the container, and for a brief instant passed through a supercritical geometry and then went subcritical again. Of course, this killed the operator of the centrifuge. When they sent people in to investigate, one of the things they did was to turn off the centrifuge (since nobody who witnessed the accident was alive, they didn't really know what had happened). Of course, this caused it to go critical again for a brief moment, severely injuring the rescue party.
Their SuSE box is somewhat more usefully set up than the others. The RedHat box seems to not allow outgoing network connections. Bah. The tru64 box doesn't have any kind of sane bash environment set up and has no X clients installed.
The SuSE box allows outgoing network connections (I have an xterm open on it) and even has ssh installed!
By the way, be careful typing those IP addresses... I got the wrong one by mistake and in place of a login I got something like "This is not a public machine. Your attempt to connect has been logged."
I don't know about other nameservers, but BIND has support for the AAAA record, which is like an A record but for an ipv6 address. So if you're using a recent version of BIND, you can have it serve up ipv4 and ipv6 addresses for the same name, depending on what the resolver asks for.
I wrote a silly cgi script to do the same thing last year. Didn't think it worthy of being on slashdot. It's not quite as cool, but it does do .com .org and .net.
http://www.stack.portland.or.us/cgi-bin/dict
You sort of got the lead part backwards :) Lead stops gammas perfectly well. You have to be careful when using lead to shield betas, because you get bremstrahllung (sp?) X-rays. Compact neutron shielding is the hardest one. You first have to thermalize any fast neutrons (with water or some kind of plastic with lots of hydrogen, for the reasons you described), then surround that with a neutron absorber (e.g. boron or cadmium), but _that_ produces gammas (and alphas also in the case of boron), which have to further be shielded by, e.g. lead.
But they're looking at neutrinos, not neutrons anyway.
I installed linuxPPC on somebody's iMac earlier this year at an installfest. There's some real perverse pleasure in making those silly things boot Unix :) After some initial difficulties (which I don't remember too well) the install went quite smoothly, even getting X running. The mouse worked fine, so I guess the USB support is decent. However, upon starting X, the keyboard sort of stopped working--it was like it got remapped randomly. That was fun. I never heard back from him, but I would assume that something like that would be fixed by now...
The patent you refer to was claimed by PKP to cover all of PK crypto, but it expired before it ever got tested in court (1997, IIRC). So it's all good. And the RSA patent expires in about a year.
I you use a suitably strong public key algorithm and a cryptographically strong hash function (both of which are very easily available) you can generate a digital signature which can't be manipulated. See the README distributed with PGP for details.
> However, I have to wonder
:)
> about the whole code == speech thing.
You used a C conditional operator in that sentence
(I'm not trying to make too much of a point, I just found it amusing)
He makes a very valid point about TMI: nobody was hurt. The outcome of the TMI accident is a great testament to the good design of American power reactors. If the same thing had happened to, say, a Russian RBMK reactor, it would have been another Chernobyl, no question. You can't expect anything nearly as complicated as a power reactor to go for decades in hundreds of installations across the country without having problems; but the fact that they have done so without harming *people* shows how reliable the system is. Regardless of how underhanded a utility company may be, the NRC is pervasive and persistent enough to keep them out of trouble. I've seen NRC inspections first hand, and those guys absolutely will not let anything slip by them. Popular paranoia about corruption goes to really extreme levels. I was talking with an NRC examiner the other day (I was taking a license exam) and he was telling me that when they visit a power plant for inspection, they have to go to ridiculous extremes to avoid being seen in public with any plant personnel, because people from "watchdog groups" follow them around and publicly accuse them of being in the plant officials' pocket if they're seen together.
The entire bit about terrorists is bogus. First of all, nothing in a power reactor, or just about any other reactor for that matter, is of any use to terrorists. The fuel is of a very low enrichment, and furthermore the plutonium produced by neutron activation of U238 contains too many other Pu isotopes to be of any use without doing isotope separation, which no terrorist organization is even remotely capable of doing. Not to mention that new fuel is immediately irradiated to make it impossible to remove from the facility without killing yourself. Bombing a power plant is also not a real threat. Power reactor containment structures are designed to withstand being directly hit by crashing jetliners. If a terrorist has weapons of similar power and is planning on using them, people should definitely be concerned about more than just the threat to power reactors. You also seem to misunderstand what the effects of bombing a reactor would be: it would be just like bombing any other building, except that if you succeeded in blowing it open you'd release radioactive material. There is absolutely *no* *way* you can make a reactor do anything like a nuclesar weapon. The worst-case scenario is much more akin to Chernobyl than to Hiroshima.
El Gamal, ECC, Diffie-Hellman... Read the FAQ at www.rsa.com
I think it would definitely suck to have these things everywhere, but my main concern would not be radiation, but privacy. I have no problems with them being in just airports. Not that I mean to defend this type of thing, but if they did become so pervasive the dose these things give you would have to be lowered first. Members of the public aren't allowed to be exposed to >100mRem per year, or >2mRem in an hour.
Higher altitude (less atmospheric shielding from cosmic rays), and the soil/rocks there contain more uranium than most other places (uranium itself is hardly radioactive, but radon is produced by its decay, and radon decays into a series of short-lived solids which hang out in your lungs).