My PhD thesis took forever, and by the time it was finished, I wanted to run screaming from anything to do with it, so I never transfered the work into papers, and became a computer programmer.
No, the *fusionable* material deteriorates rapidly.*
I infer from the article that the fissionable material is enriched uranium, i.e. U235 (mixed with U238). U235 has a half life of 700 million years. (http://www.epa.gov/radiation/radionuclides/uraniu m.htm).
So there is still a chunk of weapons-grade uranium in this thing. (I agree nothing else would be of use to a would-be nuclear weapon maker.)
* Quick summary: Fission = heavy nuclei spliting. Fusion = light nuclei combining. A nuclear bomb (e.g. Hiroshima) works by fission. A hydrogen bomb works by fusion, but needs a nuclear bomb to trigger it.
Doing IR/submillimetre during the summer: You can't let the sun fall on the mirrors (thermal warping, plus you really have to worry about where that image of the sun goes...). JCMT gets around this with a cover that is opaque to sunlight but transparent to submillimetre. I don't know if such a cover is available for far IR, and you'd still have to worry about the image of the sun. You also have a much smaller dish for your money than a dedicated submillimetre telescope would have.
Still, that is an interesting idea, and it would be worth crunching the numbers to see how much it would cost to adapt the telescope to daylight submillimetre observations, and how that compares to a dedicated telescope. (I did my PhD observations in submillimetre, at CSO.)
You're right: $3/kg is less than I expected. You do have extra costs beyond a normal observatory for automation and redundancy, because nobody is there to fix it.
Can you land a Hercules at Dome C? I'd expect the thin air to mean you'd have to land very fast, possibly too fast to be safe.
OK, I should have put 'extreme cold' under both pro (for IR, sub-mm, where it helps) and con (visual, UV, where it doesn't help, and causes problems).
The optical arangement is unlike any I've seen before or heard of. I don't have the expertise or the information to comment on whether it will really work. I'll just comment that making optically flat mirrors was very hard (much harder than the normal curved mirrors) last time I heard, but there might be new technology to help here.
There are basically three competing locations: space, Antarctica, somewhere else on Earth. There is an order of magnitude or more in accessibility and cost between each option.
Space: Pro: Access to the full range of wavelengths - no atmospheric absorption or emission. (Particularly useful in UV and IR.) No atmospheric bluring - diffraction limited resolution at all wavelengths Can observe almost any part of the sky at any time. Con: Hugely expensive Very inaccessible - service missions are either impossible or cost hundreds of millions or more Size limitations on launch - either the telescope is smallish (Hubble) or needs even more expense to 'unfold' in orbit (new generation space telescope). Very hostile environment: cold on one side, hot on another, radiation belts,...
Antarctica: Pro: Access to wavelengths difficult or impossible to access elsewhere on Earth (mostly mid to far IR. The ozone hole presumably helps out in UV also.) Best seeing on the planet: very little atmospheric blur much of the time. Con: Can only ever view half the sky Unusable during summer Very expensive Poor accesibility: Only during summer, only at great expense. Hostile environment: extreme cold. Possible build up of ice by sublimation deposition.
Anywhere else: Pro: Cheapest Daily access, can drive a truck up to the telescope Can have astronomers on site, e.g. debugging new detectors Can see the northern hemisphere Con: Poor seeing Many interesting wavelengths inaccessible or hard to observe Unusable during the day
We need all three - space for what we can't do on Earth, Antarctica for what we can't do elsewhere (except space, which costs more). Whether the telescope described (very briefly...) in the article is sensible I couldn't say, nor could I say whether it makes sense to use Dome C rather than the more accessible, and manned, south pole base.
> I think it only looks linear because the part less than 7 and more than 14 have clipped.
The vertical scale starts at zero, so I don't think it can be said to be clipped at the bottom. It is clipped at the top by mechanical design - the gearbox won't transmit more than 500 kW to the generator.
IA also NAM, but they are planning to build a bunch of these on hills near where I live. I trust that they've done their research and the turbine is suitable for the conditions.
I've just checked the website for an existing windfarm near the proposed site. It has an 'installed capacity' of 31.68MW and reverse engineering some of their figures I calculate it has mean output of 14.7MW, 46% of capacity. http://www.trustpower.co.nz/Content/Generation/Win dFarms/Tararua.aspx
For one particular turbine (http://www.windflow.co.nz/windflow500/) the power-vs-wind speed graph is pretty close to linear, increasing from zero at 7 m/s to full at 14 m/s. I see where you get your 'cube of wind speed' from, but evidently it doesn't translate into the rate at which we can extract the energy from the wind.
This turbine is also an interesting example of incremental technology improvements to the cost effectiveness. The major point of this turbine is that it has a torque limiting gearbox. This means you don't have to over-design your gearbox by a large factor to deal with the stresses of wind gusts, hence everything becomes lighter and cheaper.
Full disclosure: I am a shareholder in the company that produces this turbine.
Are the dual cores on the same piece of silicon? This would require both cores to be defect free. If only one core is defect free, is it possible to disable the dud and sell it as a single core CPU? This would make it a much more attractive proposition for the manufacturers.
E.g. if a single core has a yeild (probability of being defect free) of 80%, then the dual core chips will have a yeild of 0.8^2 = 64%. (Actually slightly lower, because whatever interconnect they have also has to be free of defects.) 64% will have two good cores, 4% will have two bad cores, the remaining 32% will have one good core. The manufacturer would obviously like to make use of that 32% if they can.
The current system will eventually break under its own weight. Universities can ill afford to continue to see large increases in their subscription rates. As the prices increase, so does the number of titles being dropped. Scientific inquiry suffers as a result.
When I was a graduate student in astronomy at Princeton University a bit over 10 years ago, one of the journals, "Astrophysics and Space Science", increased their subscription rate from I think about $1600 per year to $2000. (I'd rate ApSS as about the 6th most important astronomical journal.*) The department spent some time considering whether they would renew. (They did.)
So if the astronomy department of Princeton University is seriously considering dropping the journal, who can they have left on their subscription list?
(I see they are still publishing, at just over $3000 now. http://www.kluweronline.com/issn/0004-640X. Warning: they won't let you see anything unless you let them set session cookies.)
* ApJ, A&A, AJ, MNRAS, PASP, ApSS. Not sure about the order of AJ and MNRAS.
Despite the semi-sarcastic response, I actually have two 'accidental' degrees myself, so I know it can happen. In the course of my BSc and MSc I passed enough advanced computer science courses to be half way to a postgraduate diploma, and I had a half year to kill before starting my astronomy PhD (different hemisphere) so I took a half-time course to get the diploma. The other accidental degree is my MA(!) which I picked up on the way to the PhD.
The end result is I now have more degrees than any sane person would get. Whether this is cause or effect is left as an exercise for the student.
I have an English BA, which I picked up accidentally while working on my CS BS.
Response 1: So you're the bastard whose got it! I just put it down for a few minutes beside the printer in the computer lab, and when I got back it was gone!
Response 2: Lucky sod - the rest of us have to work at picking up girls/guys.
Portable music player - useful device. Portable video player - yes, that goes well with the music player. Still photograph displayer - might as well, we already have all the required hardware.
Next episode:
Why settle for just looking at photos? We could add a camera to this. Hey, it has audio, and takes photos - let's add a cellphone.
Whats the odds there are engineers somewhere in the world working on this right now?
Here's the dope on sulphur mining on White Island.
The island was mined from 1874 to 1900, with a break because of the 1886 Tarawera eruption. Mining resumed in 1914, but the operation was anihilated later that year by a minor eruption. There was further mining between 1923 to 1930 but finally closed because of financial losses.
I don't think that it requires an inside job. White Island isn't hard to get to, and there is nothing to stop people from landing on it other than a sense of self preservation*. The approximate location of the camera would be easy to find by looking at the landscape, and then I expect it is part of a hut full of scientific equipment - there is no good reason to have tried to hide it.
* It isn't really that dangerous. Indeed, people used to live there, mining sulphur. This went on for some years until one day the boat from the mainland came to find the mine and mining camp obliterated by a minor eruption. This was all a long time ago - perhaps the 1930s, but I'm guessing here.
"Sculpture of DNA using shopping carts" is an interesting idea, but this is about as boring an implementation of it as I could imagine. In particular, the shopping carts aren't doing anything - it could have equally well been a scuplture of DNA using rocking chairs, old tires, washing machines, small bushes, whatever.
Shopping carts slide into each other, so they have a natural way of connecting. Add some extra twiddles so you have four types, such that only some pairs can slide into each other and you can use the shopping carts as the nucleotides.
This sculpture is supported by a single central column (absent in DNA) but is missing the two helical backbones. It isn't so much that this is less accuate, but it is also less interesting (but undoubtedly cheaper and structurally simpler.)
Using the great and wonderful words program, I find you're using passive mood and subjunctives, but, alas, I never reached those chapters in my Latin text book.
I'm guessing "The people wish to be deceived, therefore they may be deceived."
I fear that, despite the.sig, my Latin is quite limited.
"d00d" = vocative singular. "que"=??? but "qu..." words are usually question words like which/what/who/where. "significa" = an instruction to show (present active indicitive 2nd person singular.) "su" = ?? Do you mean 'tu'?
There must be people who are, today, trying to run the pre-alpha Longhorn for testing etc. Not only are they doing it on sub-standard hardware (by Longhorn standards), but much of the code will not yet have been optimised*, and would run unacceptably slowly even on that dual 5GHz/2Gb machine.
I'm glad I don't have that job.
* No, I don't have inside information, just experience at the software development cycle. For anything this complicated, the early development versions run too slowly.
This is a sub-issue, although an interesting one. The utilitarian argument requires a cost-benefit analysis, so we need to assign weights to the various costs and benefits, such as rape, entertainment and enforcement effort (which at least can be measured in dollars). How much weight we assign to these is highly debatable.
"But porn can never be eliminated completely" is not a valid argument to not attempt to eliminate some. There is likely to be a law of deminishing returns: if $X eliminates half of porn, $2X will eliminate three quarters, $3X will eliminate seven eights, etc. The more we spend, the less porn we remove per dollar.
The utilitarian approach would identify an optimum level of effort at repression, beyond which the cost would exceed the benefit.
You're arguing in utilitarian terms: that banning porn costs more than it gains. I'm more interested in the utilitarian/libertarian contrast: *if* somehow the cost of banning porn was cheap enough to be justified from a utilitarian point of view, should we do it? (Or alternatively if the cost of non-banning is increased. Your arguments apply equally to child porn.)
The real issue is how we value freedom. A utilitarian could set the value of freedom somewhere between zero and comparable to the other elements in the equation. A libertarian sets the value very high.
Libertarians should also consider the fact that freedoms can collide - what about the freedom to walk through a park at night without fear of being raped?
To wrap up: Rights/freedoms always have the potential to come into conflict. Anyone who insists that one particular right or freedom overrides all others is a dangerous fanatic. The boundaries between rights will always be somewhat arbitrary, but they must still be drawn.
Slashdot Mirror
My PhD thesis took forever, and by the time it was finished, I wanted to run screaming from anything to do with it, so I never transfered the work into papers, and became a computer programmer.
Now I'm back in academia in bioinformatics.
No, the *fusionable* material deteriorates rapidly.*
u m.htm).
I infer from the article that the fissionable material is enriched uranium, i.e. U235 (mixed with U238). U235 has a half life of 700 million years. (http://www.epa.gov/radiation/radionuclides/urani
So there is still a chunk of weapons-grade uranium in this thing. (I agree nothing else would be of use to a would-be nuclear weapon maker.)
* Quick summary: Fission = heavy nuclei spliting. Fusion = light nuclei combining. A nuclear bomb (e.g. Hiroshima) works by fission. A hydrogen bomb works by fusion, but needs a nuclear bomb to trigger it.
Yes, but you could put it a few km away from the pole.
Advantages: can be fixed/resupplied from base in winter, cheaper to ship stuff to, cheaper to build because housing for workers is already nearby.
Disadvantages: not such a good site: More atmosphere, not as cold (which is good for IR stuff.)
Doing IR/submillimetre during the summer: You can't let the sun fall on the mirrors (thermal warping, plus you really have to worry about where that image of the sun goes...). JCMT gets around this with a cover that is opaque to sunlight but transparent to submillimetre. I don't know if such a cover is available for far IR, and you'd still have to worry about the image of the sun. You also have a much smaller dish for your money than a dedicated submillimetre telescope would have.
Still, that is an interesting idea, and it would be worth crunching the numbers to see how much it would cost to adapt the telescope to daylight submillimetre observations, and how that compares to a dedicated telescope. (I did my PhD observations in submillimetre, at CSO.)
You're right: $3/kg is less than I expected. You do have extra costs beyond a normal observatory for automation and redundancy, because nobody is there to fix it.
Can you land a Hercules at Dome C? I'd expect the thin air to mean you'd have to land very fast, possibly too fast to be safe.
OK, I should have put 'extreme cold' under both pro (for IR, sub-mm, where it helps) and con (visual, UV, where it doesn't help, and causes problems).
I know the feeling. I've got friends who it is impossible to socialize with anymore unless you go onto DAoC.
I'm an ex-astronomer, so I'll comment on this.
...
The optical arangement is unlike any I've seen before or heard of. I don't have the expertise or the information to comment on whether it will really work. I'll just comment that making optically flat mirrors was very hard (much harder than the normal curved mirrors) last time I heard, but there might be new technology to help here.
There are basically three competing locations: space, Antarctica, somewhere else on Earth. There is an order of magnitude or more in accessibility and cost between each option.
Space:
Pro:
Access to the full range of wavelengths - no atmospheric absorption or emission. (Particularly useful in UV and IR.)
No atmospheric bluring - diffraction limited resolution at all wavelengths
Can observe almost any part of the sky at any time.
Con:
Hugely expensive
Very inaccessible - service missions are either impossible or cost hundreds of millions or more
Size limitations on launch - either the telescope is smallish (Hubble) or needs even more expense to 'unfold' in orbit (new generation space telescope).
Very hostile environment: cold on one side, hot on another, radiation belts,
Antarctica:
Pro:
Access to wavelengths difficult or impossible to access elsewhere on Earth (mostly mid to far IR. The ozone hole presumably helps out in UV also.)
Best seeing on the planet: very little atmospheric blur much of the time.
Con:
Can only ever view half the sky
Unusable during summer
Very expensive
Poor accesibility: Only during summer, only at great expense.
Hostile environment: extreme cold. Possible build up of ice by sublimation deposition.
Anywhere else:
Pro:
Cheapest
Daily access, can drive a truck up to the telescope
Can have astronomers on site, e.g. debugging new detectors
Can see the northern hemisphere
Con:
Poor seeing
Many interesting wavelengths inaccessible or hard to observe
Unusable during the day
We need all three - space for what we can't do on Earth, Antarctica for what we can't do elsewhere (except space, which costs more). Whether the telescope described (very briefly...) in the article is sensible I couldn't say, nor could I say whether it makes sense to use Dome C rather than the more accessible, and manned, south pole base.
> I think it only looks linear because the part less than 7 and more than 14 have clipped.
n dFarms/Tararua.aspx
The vertical scale starts at zero, so I don't think it can be said to be clipped at the bottom. It is clipped at the top by mechanical design - the gearbox won't transmit more than 500 kW to the generator.
IA also NAM, but they are planning to build a bunch of these on hills near where I live. I trust that they've done their research and the turbine is suitable for the conditions.
I've just checked the website for an existing windfarm near the proposed site. It has an 'installed capacity' of 31.68MW and reverse engineering some of their figures I calculate it has mean output of 14.7MW, 46% of capacity. http://www.trustpower.co.nz/Content/Generation/Wi
For one particular turbine (http://www.windflow.co.nz/windflow500/) the power-vs-wind speed graph is pretty close to linear, increasing from zero at 7 m/s to full at 14 m/s. I see where you get your 'cube of wind speed' from, but evidently it doesn't translate into the rate at which we can extract the energy from the wind.
This turbine is also an interesting example of incremental technology improvements to the cost effectiveness. The major point of this turbine is that it has a torque limiting gearbox. This means you don't have to over-design your gearbox by a large factor to deal with the stresses of wind gusts, hence everything becomes lighter and cheaper.
Full disclosure: I am a shareholder in the company that produces this turbine.
Are the dual cores on the same piece of silicon? This would require both cores to be defect free. If only one core is defect free, is it possible to disable the dud and sell it as a single core CPU? This would make it a much more attractive proposition for the manufacturers.
E.g. if a single core has a yeild (probability of being defect free) of 80%, then the dual core chips will have a yeild of 0.8^2 = 64%. (Actually slightly lower, because whatever interconnect they have also has to be free of defects.) 64% will have two good cores, 4% will have two bad cores, the remaining 32% will have one good core. The manufacturer would obviously like to make use of that 32% if they can.
The current system will eventually break under its own weight. Universities can ill afford to continue to see large increases in their subscription rates. As the prices increase, so does the number of titles being dropped. Scientific inquiry suffers as a result.
When I was a graduate student in astronomy at Princeton University a bit over 10 years ago, one of the journals, "Astrophysics and Space Science", increased their subscription rate from I think about $1600 per year to $2000. (I'd rate ApSS as about the 6th most important astronomical journal.*) The department spent some time considering whether they would renew. (They did.)
So if the astronomy department of Princeton University is seriously considering dropping the journal, who can they have left on their subscription list?
(I see they are still publishing, at just over $3000 now. http://www.kluweronline.com/issn/0004-640X. Warning: they won't let you see anything unless you let them set session cookies.)
* ApJ, A&A, AJ, MNRAS, PASP, ApSS. Not sure about the order of AJ and MNRAS.
So my habit of reading a book as I walk along is possibly not the best idea?
Despite the semi-sarcastic response, I actually have two 'accidental' degrees myself, so I know it can happen. In the course of my BSc and MSc I passed enough advanced computer science courses to be half way to a postgraduate diploma, and I had a half year to kill before starting my astronomy PhD (different hemisphere) so I took a half-time course to get the diploma. The other accidental degree is my MA(!) which I picked up on the way to the PhD.
The end result is I now have more degrees than any sane person would get. Whether this is cause or effect is left as an exercise for the student.
I have an English BA, which I picked up accidentally while working on my CS BS.
Response 1:
So you're the bastard whose got it! I just put it down for a few minutes beside the printer in the computer lab, and when I got back it was gone!
Response 2:
Lucky sod - the rest of us have to work at picking up girls/guys.
The story so far:
Portable music player - useful device.
Portable video player - yes, that goes well with the music player.
Still photograph displayer - might as well, we already have all the required hardware.
Next episode:
Why settle for just looking at photos? We could add a camera to this.
Hey, it has audio, and takes photos - let's add a cellphone.
Whats the odds there are engineers somewhere in the world working on this right now?
Here's the dope on sulphur mining on White Island.
The island was mined from 1874 to 1900, with a break because of the 1886 Tarawera eruption. Mining resumed in 1914, but the operation was anihilated later that year by a minor eruption. There was further mining between 1923 to 1930 but finally closed because of financial losses.
I don't think that it requires an inside job. White Island isn't hard to get to, and there is nothing to stop people from landing on it other than a sense of self preservation*. The approximate location of the camera would be easy to find by looking at the landscape, and then I expect it is part of a hut full of scientific equipment - there is no good reason to have tried to hide it.
* It isn't really that dangerous. Indeed, people used to live there, mining sulphur. This went on for some years until one day the boat from the mainland came to find the mine and mining camp obliterated by a minor eruption. This was all a long time ago - perhaps the 1930s, but I'm guessing here.
"Sculpture of DNA using shopping carts" is an interesting idea, but this is about as boring an implementation of it as I could imagine. In particular, the shopping carts aren't doing anything - it could have equally well been a scuplture of DNA using rocking chairs, old tires, washing machines, small bushes, whatever.
Shopping carts slide into each other, so they have a natural way of connecting. Add some extra twiddles so you have four types, such that only some pairs can slide into each other and you can use the shopping carts as the nucleotides.
This sculpture is supported by a single central column (absent in DNA) but is missing the two helical backbones. It isn't so much that this is less accuate, but it is also less interesting (but undoubtedly cheaper and structurally simpler.)
Populus vult decipi, ergo decipiatur.
Using the great and wonderful words program, I find you're using passive mood and subjunctives, but, alas, I never reached those chapters in my Latin text book.
I'm guessing "The people wish to be deceived, therefore they may be deceived."
and whose pretending? I openly reveal my level of experience whenever it is relevant, as above. Do you expect a CV of Latin experience with every .sig?
Well the quote is original from me.
I fear that, despite the .sig, my Latin is quite limited.
.sig means:
.sigs in my journal.
"d00d" = vocative singular.
"que"=??? but "qu..." words are usually question words like which/what/who/where.
"significa" = an instruction to show (present active indicitive 2nd person singular.)
"su" = ?? Do you mean 'tu'?
(words is your friend.)
The
"Four things in this world are sacred: books, children, freedom and generosity."
I have a collection of other peoples Latin
There must be people who are, today, trying to run the pre-alpha Longhorn for testing etc. Not only are they doing it on sub-standard hardware (by Longhorn standards), but much of the code will not yet have been optimised*, and would run unacceptably slowly even on that dual 5GHz/2Gb machine.
I'm glad I don't have that job.
* No, I don't have inside information, just experience at the software development cycle. For anything this complicated, the early development versions run too slowly.
I've seen a bumper sticker:
Forth [heart] If Honk Then
But will the EULAs on new songs allow AT&T to add them to their database?
(Woohoo - EULAs and music copyright - karma whoring, here I come!)
This is a sub-issue, although an interesting one. The utilitarian argument requires a cost-benefit analysis, so we need to assign weights to the various costs and benefits, such as rape, entertainment and enforcement effort (which at least can be measured in dollars). How much weight we assign to these is highly debatable.
"But porn can never be eliminated completely" is not a valid argument to not attempt to eliminate some. There is likely to be a law of deminishing returns: if $X eliminates half of porn, $2X will eliminate three quarters, $3X will eliminate seven eights, etc. The more we spend, the less porn we remove per dollar.
The utilitarian approach would identify an optimum level of effort at repression, beyond which the cost would exceed the benefit.
You're arguing in utilitarian terms: that banning porn costs more than it gains. I'm more interested in the utilitarian/libertarian contrast: *if* somehow the cost of banning porn was cheap enough to be justified from a utilitarian point of view, should we do it? (Or alternatively if the cost of non-banning is increased. Your arguments apply equally to child porn.)
The real issue is how we value freedom. A utilitarian could set the value of freedom somewhere between zero and comparable to the other elements in the equation. A libertarian sets the value very high.
Libertarians should also consider the fact that freedoms can collide - what about the freedom to walk through a park at night without fear of being raped?
To wrap up: Rights/freedoms always have the potential to come into conflict. Anyone who insists that one particular right or freedom overrides all others is a dangerous fanatic. The boundaries between rights will always be somewhat arbitrary, but they must still be drawn.