Alas, "pages 113 to 291 are not shown in this preview". How frustrating.
Wow, that's annoying.
Okay, it makes sense for lenses, but is it true for mirror/tower systems as well?
Yes, it's a general result for any optical system, of any kind.
Obviously you'd hit a practical limit long before you tiled the ground with mirrors all the way to the horizon that pointed back at a tower concentration point, but it would still seem like a very high concentration factor would be theoretically possible.
Actually, that's only if you concentrate light onto one side. In principle, you can double that, concentrating light onto both the front and the back. Then (the Winston concentrator trick) you can increase the factor a little more with a high-index secondary.
and that the maximum theoretical temperature is 5500C. That makes sense for temperature,
Right, maximum temperature is the temperature of the surface of the sun.
and I'm guessing intuitively that the same rationale would exist for the light flux -- the equivalent of whatever it is at the Sun's surface is the maximum that could be attained.
I wasn't aware there was a theoretical concentration limit. Where did you get that from and what's the rationale for it?
The theoretical concentration limit is straightforward-- it comes from the fact that the sun has a non-zero solid angle. Basically, a concentrator works by increasing the fraction of the sky that's filled by the sun, and the best you can do is to make the light come from the whole sky. (Well, there's also a factor of n, the refractive index).
The book Solar Electricity by T. Markvart gives a calculation (page 237-- it's available on googlebooks)
The press office at U. Michigan has gone a long way from what they actually did to what they are speculating might be theoretically be possible. What they actually did was to predict a theoretical effect which has not yet been demonstrated. The press office then suggests that if you concentrate sunlight by a factor of a hundred million-- about seven hundred times higher than the theoretical concentration limit-- that this as-yet-unidentified material might be able to convert the light into electricity. This is a bit speculative. They've predicted an interesting theoretical effect. Let's keep it at that, which is a nice piece of work, and leave the speculation to science fiction writers (like me).
Page is taking a number of steps to help alleviate the "sluggish decision making" he sees at Google. This has included meeting with managers and trying to limit the number of projects in each engineering department
and then, two paragraphs later:
what he thinks Google needs to do to achieve Page's goals. Mostly, it involves letting engineers loose to innovate.
Which is it that they want to do? Decrease the number of projects, or free the engineers to start new projects?
If they're proposing to set up a new bureaucracy that will examine every project and kill the ones that the manager doesn't like, with the intent to "limit the number of projects," that's hardly "letting engineers loose to innovate."
About frakking time. Corporations should have no more access to human rights than a tree or rock or building. If an entity can not vote, then it should not have rights.
More importantly, if a corporation can't be put in jail for wrongdoing, it shouldn't have rights.
This was well researched during the Reagan years. Money spent on defense does less to stimulate the economy than other government spending, which in turn does less than private spending, but it's not a huge difference.../p>
The main problem, as far as I can see, is that IT people are busy demanding users adopt procedures to deal with threats that don't exist, rather than threats that do exist. In all of the many scare-laden emails from our IT department, I don't believe that I have ever once seen one telling us don't use the same password on multiple systems, that's insecure. They do, however, rigorously enforce the fact that passwords must be changed every 60 days, and are specified to be complex enough that a brute-force attack will take 6E17 years, instead of the old insecure passwords that could be broken in a mere 3E9
The article is a little unfair; to be fair it would have to subtract people saved by GPS.
Frankly, people have always gotten lost, dating right back to at least the time Moses wandered for 40 years in the Sinai. Surely GPS has also gotten people out of trouble. The question is, what's the net effect?
What about the scientist's claim that they have a prototype running continuously providing a factory with heat for the last 6 months ? [...] Unless that information is a hoax as well, there's something serious about this.
Until people can independently verify this information, it's just stuff that they say. They can claim anything they like. They can claim that they have ten trillion percent efficiency, conversion of lead into gold, a cure for cancer, and time travel, too-- but until somebody else sees it, it's just claims.
...On the non-disclosure. Those guys have more to gain by keeping this under as much wraps as possible from other scientists....
Yeah. Except that this is always what gets said when they won't let anybody else see their miracle machines... and somehow the miracle machines never do end up getting revealed to the world. If they did, in fact, what they say they did, they would become the most famous human beings in the world by letting other people see it (and, as a bonus, their patents would not be rejected).... but, no, rather than be the most famous human beings on the planet, they "have more to gain" by not letting anybody see it.
Earning a degree has nothing to do with class. Anyone can get into college. Can't afford it? Join the military, get loans, scholarship or work three jobs while going to school.
Oh, sure, you can... but it is hard. If your parents are affluent enough to pay for college, or even to assist with paying for college; it is easy. (or at least, easier.)
I served two years in the US Army, took out loans and worked two jobs to put myself and my wife through college. I have a bachelors and my wife earned her masters. We were both raised by single parents who worked multiple jobs to put food on the table. Neither of our parents paid for our education.
Which is exactly the point. It's hard.
Congrats to you for sticking it out despite obstacles, but when people have to serve two years in the military, take out loans, and still have to work two jobs to pay for college, no surprise, but a lot of them don't make it through.
Of course, it helps to have mommy and daddy pay your way so you don't even have to hold a job while in school.
Bingo.
I knew some of these people, and frankly, I got much more out of college than they did.
And if the discussion were about "getting more out of college" and not about "getting into college," then that would have been relevant.
Isn't this more an indiciation of a widening income gap between working class and middle class backgrounds? There are a lot of not-so-smart people with degrees.
Agreed.
More specifically, it is a sign of the disappearance in America of the relatively high-paid manufacturing jobs, the classic "blue collar" jobs. In my parents time, a person could make a good living in a job on the auto line, or working in the steel mill. These jobs are gone (or, if not totally gone, there are a lot less of them then there were.)
Simultaneously, the absolute numbers of Americans getting college degrees is going up, and so even jobs that don't actually require a degree are taking people who have one, except for the minimum wage jobs at the very bottom of the scale (typically in the "service" economy).
So, uh, you are taking one article that is apparently written somewhat tongue in cheek, plus one (1) video, which has been disowned by pretty much every environmental group on the planet, as evidence that "greenies" "view humans as utterly expendable."
I think you could apply Niven's law to this. ("No cause is so noble that it won't attract its share of fuggheads"), not to mention Pournelle's corrolary ("...who will inevitably be the ones interviewed by the press.")
The article is, of course, being stupid-- deliberately stupid, I expect, but still stupid.
The anthropogenic greenhouse effect was not a problem in the 13th century, and the the total amount of carbon dioxide that had been emitted by the entire human race at that point was trivial. To the extend that his conquests removed carbon dioxide from the atmosphere, it was addressing a problem that didn't exist.
I will also point out that current carbon dioxide emission is about 30 billion tons per year. If the Mongols removed "700 million tons" of carbon from the atmosphere, then in the course of a century and a half of Mongol rule they accomplished the removal of an amount of carbon dioxide equal to about one week of modern emission.
It's most likely not a success but I just want to touch on the logical fallacy there.
Simply being unable to explain a phenomenon doesn't mean a scientist hasn't discovered something new.
It's most likely not a success but I just want to touch on the logical fallacy there.
Simply being unable to explain a phenomenon doesn't mean a scientist hasn't discovered something new.
True.
However, it should also be noted that simply because they say that their work was only rejected because they didn't have a theory doesn't mean that their work was not, also, rejected because the work was not credible.
Perhaps they simply gave them one of the first few common eliminators they use to reject amateur submissions.
Perhaps. And perhaps they selectively quoted one item from a longer negative review, saying something akin to "does not provide experimental evidence (nor any firm theoretical basis)."
So why were the hippies signing about living in the "age of Aquarius" 40 years ago? Surely that was not the most recent time Aquarius came around? Enlighten me, please.
Well, the phrase was "it is the dawning of the age of Aquarius." So, they started celebrating a little early.
(reference: Rado and Ragni, 1967)
For me, I hope No One minds when I switch from Cancer to Gemini, Ive always hated crabs with terminal diseases as a sign!
The original Babylonian constellation was called "crayfish," does that help?
What I find amusing is that (now mostly forgotten) SF writer John Sladek figured out that there ought to be 13 constellations in the zodiac, rather than 12 (on the argument that there are not 12, but 12 1/2 lunar months in a year-- need an extra constellation to account for one per month)-- and wrote a satirical "nonfiction" book "Arachne Rising" explaining the conspiracy that "suppressed" the missing 13th constellation. (under the pseudonyn "John Vogh"). That's why astrology is usually wrong, everybody! The secret 13th sign of the zodiac (now called "Ophiuchus," but formerly* Arachne) isn't used!
Would have to precisely define "objective satellite data" to a specific measuring methodology, technology, and sensitivity.
Indeed, this is a very tricky point: can Bastardi and the hypothetical person who takes the bet agree on what data set is objective?
In general, one of the main arguments of the climate-change deniers have been to claim that the data is wrong. If they don't believe the data up to now, why would they accept it as accurate to settle a bet? And, more to the point, even if they do agree on the data now-- well, Exxon-Mobil is not going to stop funding attacks on the science and there will -- you can bet on this-- be many more attacks claiming that the data is wrong, fraudulent, inaccurate, measured in the wrong places, and so forth. So, when the bet does get settled, why would we think anything is settled? Why do we think he won't just say "well, yes, I did paid off because I said I would, but nevertheless I don't believe that data."
Um, since the Democrats hold two out of three of the elective branches of the US government, I don't see how you can call them "a minority party."
She is also the wife of astronaut Mark Kelly, a member of the House committee on Science and Technology, and the chairwoman of the House subcommittee on Space and Aeronautics; so this is news of interest to anybody interested in science and technology.
Not dead, but according to the New York Times report, it doesn't sound good. This is not a minor injury:
Dr. Steven Rayle, a former emergency room doctor who now works in a hospice, said that he had witnessed the shootings. He said the congresswoman was standing behind a table outside the Safeway greeting passersby when the gunman approached her from behind, held a gun about a foot from her head and began firing.
. “He must have got off 20 rounds,” he said. Ms. Giffords slumped to the ground and staff members immediately rushed to her aid, Dr. Rayle said.
Dr. Rayle said he performed CPR on some of the victims. He said one of the victims was a young child and appeared to be in critical condition with a gunshot wound.
Representative Giffords is the wife of astronaut Mark Kelly, and seems to be one of the few congresspeople who are knowledgable about science and technology.
Slashdot Mirror
Alas, "pages 113 to 291 are not shown in this preview". How frustrating.
Wow, that's annoying.
Okay, it makes sense for lenses, but is it true for mirror/tower systems as well?
Yes, it's a general result for any optical system, of any kind.
Obviously you'd hit a practical limit long before you tiled the ground with mirrors all the way to the horizon that pointed back at a tower concentration point, but it would still seem like a very high concentration factor would be theoretically possible.
Hmmm... with a bit of google hunting I found this page, where it states the maximum concentration factor is 46211x,
Actually, that's only if you concentrate light onto one side. In principle, you can double that, concentrating light onto both the front and the back. Then (the Winston concentrator trick) you can increase the factor a little more with a high-index secondary.
and that the maximum theoretical temperature is 5500C. That makes sense for temperature,
Right, maximum temperature is the temperature of the surface of the sun.
and I'm guessing intuitively that the same rationale would exist for the light flux -- the equivalent of whatever it is at the Sun's surface is the maximum that could be attained.
Exactly.
I wasn't aware there was a theoretical concentration limit. Where did you get that from and what's the rationale for it?
The theoretical concentration limit is straightforward-- it comes from the fact that the sun has a non-zero solid angle. Basically, a concentrator works by increasing the fraction of the sky that's filled by the sun, and the best you can do is to make the light come from the whole sky. (Well, there's also a factor of n, the refractive index).
The book Solar Electricity by T. Markvart gives a calculation (page 237-- it's available on googlebooks)
The press office at U. Michigan has gone a long way from what they actually did to what they are speculating might be theoretically be possible. What they actually did was to predict a theoretical effect which has not yet been demonstrated. The press office then suggests that if you concentrate sunlight by a factor of a hundred million-- about seven hundred times higher than the theoretical concentration limit-- that this as-yet-unidentified material might be able to convert the light into electricity.
This is a bit speculative. They've predicted an interesting theoretical effect. Let's keep it at that, which is a nice piece of work, and leave the speculation to science fiction writers (like me).
in one paragraph, to improve innovation:
and then, two paragraphs later:
Which is it that they want to do? Decrease the number of projects, or free the engineers to start new projects?
If they're proposing to set up a new bureaucracy that will examine every project and kill the ones that the manager doesn't like, with the intent to "limit the number of projects," that's hardly "letting engineers loose to innovate."
About frakking time. Corporations should have no more access to human rights than a tree or rock or building. If an entity can not vote, then it should not have rights.
More importantly, if a corporation can't be put in jail for wrongdoing, it shouldn't have rights.
This was well researched during the Reagan years. Money spent on defense does less to stimulate the economy than other government spending, which in turn does less than private spending, but it's not a huge difference.../p>
Interesting. Do you have a reference?
The main problem, as far as I can see, is that IT people are busy demanding users adopt procedures to deal with threats that don't exist, rather than threats that do exist. In all of the many scare-laden emails from our IT department, I don't believe that I have ever once seen one telling us don't use the same password on multiple systems, that's insecure. They do, however, rigorously enforce the fact that passwords must be changed every 60 days, and are specified to be complex enough that a brute-force attack will take 6E17 years, instead of the old insecure passwords that could be broken in a mere 3E9
The article is a little unfair; to be fair it would have to subtract people saved by GPS.
Frankly, people have always gotten lost, dating right back to at least the time Moses wandered for 40 years in the Sinai. Surely GPS has also gotten people out of trouble. The question is, what's the net effect?
I would recommend to see how all components scale down. If you make everything smaller by the same factor, does performance suffer?
Yes: this particular system (Daedalus) fails to work.
The BIS design was a design attempt at the smallest probe possible.
The new study (Icarus) revises that considerably.
For those interested, the Tau Zero Foundation (referenced in the text) does have a website, www.tauzero.aero/
What about the scientist's claim that they have a prototype running continuously providing a factory with heat for the last 6 months ?
[...] Unless that information is a hoax as well, there's something serious about this.
Until people can independently verify this information, it's just stuff that they say. They can claim anything they like. They can claim that they have ten trillion percent efficiency, conversion of lead into gold, a cure for cancer, and time travel, too-- but until somebody else sees it, it's just claims.
...On the non-disclosure. Those guys have more to gain by keeping this under as much wraps as possible from other scientists....
Yeah. Except that this is always what gets said when they won't let anybody else see their miracle machines... and somehow the miracle machines never do end up getting revealed to the world. If they did, in fact, what they say they did, they would become the most famous human beings in the world by letting other people see it (and, as a bonus, their patents would not be rejected).... but, no, rather than be the most famous human beings on the planet, they "have more to gain" by not letting anybody see it.
Earning a degree has nothing to do with class. Anyone can get into college. Can't afford it? Join the military, get loans, scholarship or work three jobs while going to school.
Oh, sure, you can... but it is hard. If your parents are affluent enough to pay for college, or even to assist with paying for college; it is easy. (or at least, easier.)
I served two years in the US Army, took out loans and worked two jobs to put myself and my wife through college. I have a bachelors and my wife earned her masters. We were both raised by single parents who worked multiple jobs to put food on the table. Neither of our parents paid for our education.
Which is exactly the point. It's hard.
Congrats to you for sticking it out despite obstacles, but when people have to serve two years in the military, take out loans, and still have to work two jobs to pay for college, no surprise, but a lot of them don't make it through.
Of course, it helps to have mommy and daddy pay your way so you don't even have to hold a job while in school.
Bingo.
I knew some of these people, and frankly, I got much more out of college than they did.
And if the discussion were about "getting more out of college" and not about "getting into college," then that would have been relevant.
Isn't this more an indiciation of a widening income gap between working class and middle class backgrounds? There are a lot of not-so-smart people with degrees.
Agreed.
More specifically, it is a sign of the disappearance in America of the relatively high-paid manufacturing jobs, the classic "blue collar" jobs. In my parents time, a person could make a good living in a job on the auto line, or working in the steel mill. These jobs are gone (or, if not totally gone, there are a lot less of them then there were.)
Simultaneously, the absolute numbers of Americans getting college degrees is going up, and so even jobs that don't actually require a degree are taking people who have one, except for the minimum wage jobs at the very bottom of the scale (typically in the "service" economy).
So, uh, you are taking one article that is apparently written somewhat tongue in cheek, plus one (1) video, which has been disowned by pretty much every environmental group on the planet, as evidence that "greenies" "view humans as utterly expendable."
I think you could apply Niven's law to this. ("No cause is so noble that it won't attract its share of fuggheads"), not to mention Pournelle's corrolary ("...who will inevitably be the ones interviewed by the press.")
The article is, of course, being stupid-- deliberately stupid, I expect, but still stupid.
The anthropogenic greenhouse effect was not a problem in the 13th century, and the the total amount of carbon dioxide that had been emitted by the entire human race at that point was trivial. To the extend that his conquests removed carbon dioxide from the atmosphere, it was addressing a problem that didn't exist.
I will also point out that current carbon dioxide emission is about 30 billion tons per year. If the Mongols removed "700 million tons" of carbon from the atmosphere, then in the course of a century and a half of Mongol rule they accomplished the removal of an amount of carbon dioxide equal to about one week of modern emission.
It's most likely not a success but I just want to touch on the logical fallacy there.
Simply being unable to explain a phenomenon doesn't mean a scientist hasn't discovered something new.
It's most likely not a success but I just want to touch on the logical fallacy there.
Simply being unable to explain a phenomenon doesn't mean a scientist hasn't discovered something new.
True.
However, it should also be noted that simply because they say that their work was only rejected because they didn't have a theory doesn't mean that their work was not, also, rejected because the work was not credible.
Perhaps they simply gave them one of the first few common eliminators they use to reject amateur submissions.
Perhaps. And perhaps they selectively quoted one item from a longer negative review, saying something akin to "does not provide experimental evidence (nor any firm theoretical basis)."
So why were the hippies signing about living in the "age of Aquarius" 40 years ago? Surely that was not the most recent time Aquarius came around? Enlighten me, please.
Well, the phrase was "it is the dawning of the age of Aquarius." So, they started celebrating a little early.
(reference: Rado and Ragni, 1967)
For me, I hope No One minds when I switch from Cancer to Gemini, Ive always hated crabs with terminal diseases as a sign!
The original Babylonian constellation was called "crayfish," does that help?
What I find amusing is that (now mostly forgotten) SF writer John Sladek figured out that there ought to be 13 constellations in the zodiac, rather than 12 (on the argument that there are not 12, but 12 1/2 lunar months in a year-- need an extra constellation to account for one per month)-- and wrote a satirical "nonfiction" book "Arachne Rising" explaining the conspiracy that "suppressed" the missing 13th constellation. (under the pseudonyn "John Vogh").
That's why astrology is usually wrong, everybody! The secret 13th sign of the zodiac (now called "Ophiuchus," but formerly* Arachne) isn't used!
*--according to Sladek.
He's a little like a 2D character in Flatland that doesn't understand 3D.
Is this a reference to Gamow's One, Two, Three... infinity?
No.
It's a reference to Flatland.
Would have to precisely define "objective satellite data" to a specific measuring methodology, technology, and sensitivity.
Indeed, this is a very tricky point: can Bastardi and the hypothetical person who takes the bet agree on what data set is objective?
In general, one of the main arguments of the climate-change deniers have been to claim that the data is wrong. If they don't believe the data up to now, why would they accept it as accurate to settle a bet? And, more to the point, even if they do agree on the data now-- well, Exxon-Mobil is not going to stop funding attacks on the science and there will -- you can bet on this-- be many more attacks claiming that the data is wrong, fraudulent, inaccurate, measured in the wrong places, and so forth. So, when the bet does get settled, why would we think anything is settled? Why do we think he won't just say "well, yes, I did paid off because I said I would, but nevertheless I don't believe that data."
Nice link, but there's no reason to think that the causation isn't the other way: people with psychosis tend to use marijuana.
It's known as "self medication." It may not be wise, but then people with psychoses are not necessarily known for good judgement.
How so? She's a minor member of a minority party.
Um, since the Democrats hold two out of three of the elective branches of the US government, I don't see how you can call them "a minority party."
She is also the wife of astronaut Mark Kelly, a member of the House committee on Science and Technology, and the chairwoman of the House subcommittee on Space and Aeronautics; so this is news of interest to anybody interested in science and technology.
Not dead, but according to the New York Times report, it doesn't sound good. This is not a minor injury:
Dr. Steven Rayle, a former emergency room doctor who now works in a hospice, said that he had witnessed the shootings. He said the congresswoman was standing behind a table outside the Safeway greeting passersby when the gunman approached her from behind, held a gun about a foot from her head and began firing.
. “He must have got off 20 rounds,” he said. Ms. Giffords slumped to the ground and staff members immediately rushed to her aid, Dr. Rayle said.
Dr. Rayle said he performed CPR on some of the victims. He said one of the victims was a young child and appeared to be in critical condition with a gunshot wound.
link: http://www.nytimes.com/2011/01/09/us/politics/09giffords.html
Representative Giffords is the wife of astronaut Mark Kelly, and seems to be one of the few congresspeople who are knowledgable about science and technology.
This is a great tragedy.
Politics should not be conducted by gunfire.
I say, I was quite surprised at this news.
This headline could have benefitted from the addition of a word such as "and".