Well, we were all sure that there would be obstacles, including tank traps, but I am pretty sure they were not actually used on the course. If you look at the course map on the DARPA site, there are no obstacles mentioned, although there are a few tunnels and cattle guards (metal grates lying flat on the ground). We all concluded from the lack of obstacles that the DARPA people simply wanted to end the competition as soon as possible, so they made the course easier than anyone expected, thus guaranteeing a win.
You are right that temporary GPS outages had to be handled (this is what screwed up our team and a few others), but in general, not longer than a few minutes long.
As a participant of another DARPA team (Cornell -- our site is down), I am skeptical as to whether the winners of the challenge would be able to drive in a real world environment. In many ways the Grand Challenge was a toy problem, but this is not usually emphasized because they want to make it seem more dramatic.
First of all, no other moving objects on the course. When a vehicle was about to pass another, the one in front was paused so that the passing vehicle could overtake it. At no time did the vehicles have to deal with changing conditions.
Secondly, to my knowledge, there were no obstacles (which were promised) on the course. If someone knows differently, I'd like to hear about it. So we don't know to what extent obstacle avoidance is effective on those vehicles.
Thirdly, daylight and clear weather is one thing, but nighttime, rain, snow, etc. would significantly degrade the data.
Essentially the problem that the current vehicles solved was this: Given a set of waypoints and a "corridor" outside which you will never have to go (so far the problem can be solved only by 10cm-accuracy DGPS), use your other sensors to avoid obstacles by moving left or right within the corridor.
Not very much like real world driving at all. And I'm not saying Stanford, CMU and the others didn't accomplish something big -- I'm just saying it's not what the Wired piece makes it out to be.
I personally prefer C#, at least as a toy language, for the following reasons: *It has some features that make it more compact, like operator overloading. *It is integrated into windows so you can make GUIs that look like other applications *It is faster *Visual studio is a better IDE than many of the Java ones *All microsoft development tools are free to students.
Now all of these are explicitly whimsical arguments. In the real world, none of this matters, because the language you use in a given project will almost never be determined by pure aesthetics. But if you are going to spend a semester working with a language you never use again, I would rather spend it with C# than Java. And, as many have already said, they are so similar that you can pick up the other very quickly.
As another poster has pointed out, this is not a metal, but a ceramic that happens to contain aluminum. Which means it is not suitable for use in structural applications like airplane fuselages, or in foil. Also, metal's opaqueness to light and radio waves bears a direct relationship to its conductivity to electricity; in effect, metal "shorts out" an oncoming electromagnetic wave. There might be some exotic metals that are transparent. Since gold is so soft, it is relatively easy to hammer into sheets of only several atoms thick. It then becomes translucent. This of course was the reason why gold leaves were used to in the famous "plum pudding" experiment that proved the existence of a nucleus in atoms, but that is beside the point.
It wasn't so long ago, in the 70's, when books were being written to the effect that as population increases exponentially, we will by the late 1990's reach a Malthusian crisis with over 20 billion people on earth fighting over the last scraps of food. That didn't happen, and that's for a process that we KNOW grows exponentially (ie population). It just so happens that for a variety of factors (though generally not famine), the growth constant changed so that in many countries the population has levelled off.
Just because you can plot a few points in time and fit an exponential curve to them doesn't mean that it will continue to be an exponential curve forever. And I find Mr. Kurzweil's particular vision of the future somewhat offensive because it is a future that would only be imaginable or appealing to an American computer nerd.
The major concrete technical point made in this article is that the file system should be invisible to the user. This has been tried by literally dozens of groups and all of them have so far failed to produce something usable. Maybe when WinFS comes out it will change things. Steve Jobs and other people at Apple have been trying to erase the distinction between open files and saved files for years (it was done in the Newton) but it never caught on. So I think all these academics who advocate the same GUI innovations for 20 years in a row should a) Try to make the innovations themselves and either succeed or prove to themselves why it's a bad idea b) Think of a new GUI innovation that hasn't been beaten to death yet
So, I have a question actually relevant to this article. The article says that the CPU was supposed to jump to address FFFF_FFFF, turn off the ROM, then roll over to 0000_0000, where the CPU would throw an exception thus halting the CPU. However, says the article, the CPU does not in fact throw an exception in this case.
So my question is, how did the hackers who reverse engineered this code conclude that it was supposed to trigger an exception? It seems hard for me to believe that the MS engineers would base their entire security mechanism on a feature of the CPU that didn't actually exist.
I was proficient on QWERTY when I started using Dvorak. It took me about two weeks to adjust to using it on my computer. I've been using it for over a year and I still find it quite comfortable. After I switched I only used QWERTY keyboards occasionally, and at first I completely lost my typing skills to the point that it was as hard to type on QWERTY as it had been when I had never typed before. However within a few months I regained my QWERTY ability as well, so now I am pretty much equally good at QWERTY and Dvorak and have no problem switching back and forth. However I do still sometimes accidentally think that a key on a QWERTY kbd should be where it is on a Dvorak, but that's rare. So point is, if you can take a few weeks of slowed down typing, you'll be fine after that.
There are the ServView systems from BlackBox which are pretty much exactly what you are asking for, here is an image. They are made to be on slide-out drawers in a rackmount cabinet but you might be able to do some creative amputation to make it more portable:)
As some posts below reveal, the accident resulted from a series of mistakes/stupid actions. If any of these mistakes had not occurred, the accident would not have happened. The removal of the safeties in itself did not cause the accident - it was the raising of control rods, removal of cooling water, etc. Then because of the positive void coefficient, lowering the control rods briefly increased the power of the reactor and caused the explosion. Once the explosion happened, it was all over -- putting out the fire quickly was pretty hopeless once the graphite had caught on fire.
I read T3, the playboy for gadget lovers. They have a girl every month just like playboy except she's not naked and not all that hot. But when I read other magazines (Popular Science, Wired, etc), my favorite part is the new gadgets section anyway. T3 is one big gadgets section every month.
I use a TI-83 and to avoid parenthesizing I have been using the ANS button a lot, which essentially amounts to doing RPN. For example instead of 1/(5+3) I will do 5+3[Enter] 1/[Ans]. But I still find the ability to do algebraic notation useful for longer expressions when I would have too many things in the "stack".
Re:Water, not Oil.
on
Out of Gas
·
· Score: 2, Funny
I guess hydrologists just see the glass as half empty then . . .
Re:The bigger picture -updated version
on
Out of Gas
·
· Score: 1
I was unaware that housepaint is sold by the watt.
So if we accept that a planet is anything that has been rounded by its own gravity, we have to make assumptions about the density of the matter that it's made of. Stars that went through a supernova and no longer have enough mass to undergo fusion may be round and of comparable size to known planets, but many times denser. They clearly are not in fact planets but the author's criterion would have it that way. Of course we can say, "They aren't planets because they used to be stars" but he threw out the entire argument-from-origins criterion as being too difficult to establish.
Conveniently, he did not make a biological analogy for the argument-from-origins -- that is because biologically, it is the most sensible argument.
What he really did was shift the question from "how big do you have to be to be a planet" to "how dense do you have to be to be a planet." Now we have to establish an upper limit to planetary density, which is hard since it's hard to see small, dense objects.
Here are some of my bookmarks with photos of abandoned places . . . don't know how well any of them work: http://members.tripod.com/airfields_freeman /index. htm http://home2.planetinternet.be/henk/index.htm l http://www.columbia.edu/~brennan/abandoned/ ht tp://www.forgottendetroit.com/ http://www.forgott en-ny.com/ http://www.acme.com/jef/photos/archaeo logy.html http://www.infiltration.org/ http://ww w.starfury.demon.co.uk/uground/ http://www.lostam erica.com/lostframe.html http://www.modern-ruins. com/ http://www.losthighways.org/radebaugh.html http://detroityes.com/toc.htm#Gilded http://e.web ring.com/hub?ring=draining&list&page=1
Regarding nuclear power, it is important to remember that uranium can run out just like fossil fuels, and in fact if we had started out using nuclear power instead of oil for energy, we would certainly have run out of nuclear fuel by now. In other words, nuclear power is not a solution except as a pollution free way to power a few dozen densely populated areas.
My view on the subject is, different groups will try to have a war in space. I don't know if it will be practical. We have already seen that the more modern two militaries are, the less willing they are to fight, because the hardware is just so expensive and the weapons so effective. Since WWII, there hasn't been a single war between two modern militaries with approximately equal capabilities. No two countries with nuclear weapons have fought, because again, there is no way to win when fighting with nuclear weapons.
Now, the cost of space hardware is high; stealth bombers are like peanuts compared to any imaginable space warship. And the physics are different -- since there is no drag in space, a very small projectile can do a whole lot of damage . And of course, if your entire ship weighs 10,000 pounds, you can't accelerate a 2,000 pound projectile, because you'll fly off in the opposite direction at a comparable speed.
And of course, how are you going to carry all that fuel in order to maneuver? Maybe when every spacecraft carries a fusion reactor onboard we can talk about space dogfights, but until then, it will be like the knight in Holy Grail trying to fight with no arms and no legs.
As for satellite weapons platforms, the solution is simple: bomb the mission control centers that are on the ground. That might happen. But that is not really war in space, that is a war over space.
A lot of people claim that the reason why the US doesn't use nuclear power everywhere is because of environmentalist whackos. This is not true. The reason is economics.
Back in the 50's when nuclear power was first proposed, people talked about having electricity too cheap to meter. The thing they did not consider is that a nuclear power plant costs much more to build than a coal/oil/natural gas plant. I want to make sure everyone understands why.
First of all, the radiation given off by fission destroys inorganic materials just as happily as it destroys human tissue. Very high quality metal must be used in all parts of the reactor to prevent degradation and to prevent it from becoming highly radioactive. This is even more of a problem in fusion reactors which have a much higher flow of neutrons, and in those, the only solution will be to replace the pieces every so often.
Second, the plant must be extremely highly reliable. One reason for this is draconian public safety regulations. However you have to keep in mind that even an accident that is contained within the plant and poses no risk to the public (a la Three Mile Island) can still destroy the reactor and put the plant out of commission.
This is true because of a property of the nuclear chain reaction. Dropping all of the control rods (scramming) does not instantly shut down the reaction in the way that dousing a coal fire would extinguish it. The reactor will continue to produce heat for around an hour after it is shut down. This means that it must be cooled for that hour, otherwise it will melt and flood the building with radioactive chemicals. The Chernobyl accident was caused by an attempt to test what happens if the cooling system is disabled.
So the system has to be very highly redundant, in part to protect the public, but mostly to protect the plant.
The last problem is that if the coolant is radioactive, you can't just call in a plumber to fix the leak as you might in a coal plant. See the movie K-19 Widowmaker for the effects of radioactive coolant on humans. You better make damn sure that system doesn't leak in the first place.
So the plants are expensive. This means you want economy of scale and build one large plant instead of many small ones. This means you don't want to build these plants in the Midwest where that much power just isn't useful. You want to build them near population centers. That explains why there is no nuclear power in sparsely populated places.
The other thing is that even though uranium is much cheaper than coal per joule (because you need so much less of it), the cost of the nuclear plant makes the whole process expensive enough that it has to compete with coal for the market. This means that in places where coal is cheap (as in the United States) building nuclear plants is only sensible up to a point. As the nuclear plants drive down demand for coal, the coal gets cheaper, so there is a natural feedback mechanism.
In the United States, we are a little bit below the optimal balance. We could economically build more nuclear plants but not that many. This difference is in part accounted for by the public perception of nuclear power.
It is also accounted for by the fact that it takes ten years to build a nuclear power plant, so if you have an energy crisis NOW, building a nuclear power plant is no good. California had to go with building natural gas power plants after their energy crisis because they are cheap and fast to build. Natural gas is more expensive but that's life.
Now it should be clear why France and Japan, two countries that use nuclear power for most of their needs, are able to do so while the US cannot. It has nothing to do with progressive governments or the lack of environmentalists. It is simply that France and Japan are small, densely populated countries (compared to the US) that have expensive coal (compared to the US). So they have a lot of nuclear plants (compared to the US).
Many of the posts so far have the attitude that there is an irrational fear of nuclear power and that the public is simply ignorant. There are a few points to counter that:
1)Many governments around the world, including the US government, put humans in unsafe radiation environments, which they knew to be unsafe, either to test the effect on the humans or because they didn't care. A significant number of people in the US military died because of this. There was a show on Nova about the Bikini Atoll nuclear tests, where the sailors watched the explosions from the decks of their ships. Many of those died.
You might say that this is all in the past, but look at how the Gulf War Syndrome patients have been treated by the US and UK governments. The symptoms are there, but nobody knows what causes them and so they just deny the effect and keep exposing more and more soldiers to whatever it is that causes the illness.
Look at how the US and UK governments deny the harmful effects of depleted uranium. DU munitions are not very radioactive, but the dust that is released when they burn finds its way into the human body very easily. Once inside, it can not only irradiate the body but also have other toxic effects associated with heavy metal. The military's OWN practice is aggressive decontamination of anything that is exposed to DU ash, but this is denied in official reports.
So in the absence of reliable independent reports, it is very difficult to accept these assertions of safety.
2)If only we had a way to quantify the danger posed by radiation we might not have this problem. However quantify it we cannot. Because of the random nature of radiation damage, it is very difficult to study. We know the effects of large doses fairly accurately but small doses require large population samples, and it is difficult to expose large populations to controlled doses of radiation.
The greatest danger posed by small radiation doses is genetic damage that can lead to cancer. We don't know how cancer works or how the human body normally prevents it. We don't know what enables humans to survive the genetic damage caused by the natural radiation environment. We can't even measure genetic damage. We know that USUALLY, small doses of radiation have no effect but don't know why SOMETIMES they do or what is a safe dose.
At its root, the fear of low level radiation is similar to the fear of other carcinogens. There is no way to quantify or track exposure because just ONE unlucky mutation could lead to a deadly cancer, but we have no idea which mutations these are or how to find them.
So what I would say is that those people who want to talk about irrational fears of the population should rationally counter some of these points. Most people who are pro-nuclear cannot counter them. They don't know anything about how radiation exposure is measured (except that it's in REMs), what the natural background radiation is in REMs, how many Curies are contained in coal ash, etc. etc. etc.
This is very similar to GM's HyWire concept car, which uses a motor on each wheel (though possibly not in-wheel, but still no gearbox in between). The HyWire is designed to run on fuel cells but any practical model would probably run a diesel engine also.
This is GM's site: http://www.gm.com/automotive/innovations/Fuelcell/ fuel_cell_innovation.html
Again, city bus wheels are much heavier than regular car wheels. I think it might be possible for these motors to be reasonably close to the weight of a bus wheel's hub. Especially since according to the diagram, the wheel doesn't have a mechanical brake.
The reason why gas engines need transmissions is that gas engines run on a smaller range of RPM (revolutions per minute) than the wheel. For example a gas engine can't run below a few hundred RPM, so you need a clutch and a torque convertor to start the car moving from a stop. The engine also doesn't have enough torque to start the car moving from a stop so you need to gear it down. But by the time the car is moving a10 miles per hour, the geared-down engine is spinning at its limit, so you need another set of gears with a lower ratio to avoid revving the hell out of the engine . . . the top gear in most cars is 1:1 ratio, so when the motor is spinning at 2000 RPM, so are the shafts before the differential. In overdrive, the wheels actually spin faster than the engine, that's why it's called overdrive.
An electric motor runs fine at low RPMs all the way up to fairly high RPMs so you usually don't need a transmission, unless the motor doesn't have enough torque, in which case you need to gear it down but then can't go as fast. That's the basic reason why in-wheel motors are difficult -- the motor needs to be able to spin fast and still pack a punch.
You're neglecting the increase in the weight of the body due to batteries. Also, don't forget that the average city bus wheel hub already weighs quite a bit, and is made of steel. These motors probably have a lighter casing.
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Well, we were all sure that there would be obstacles, including tank traps, but I am pretty sure they were not actually used on the course. If you look at the course map on the DARPA site, there are no obstacles mentioned, although there are a few tunnels and cattle guards (metal grates lying flat on the ground). We all concluded from the lack of obstacles that the DARPA people simply wanted to end the competition as soon as possible, so they made the course easier than anyone expected, thus guaranteeing a win.
You are right that temporary GPS outages had to be handled (this is what screwed up our team and a few others), but in general, not longer than a few minutes long.
As a participant of another DARPA team (Cornell -- our site is down), I am skeptical as to whether the winners of the challenge would be able to drive in a real world environment. In many ways the Grand Challenge was a toy problem, but this is not usually emphasized because they want to make it seem more dramatic.
First of all, no other moving objects on the course. When a vehicle was about to pass another, the one in front was paused so that the passing vehicle could overtake it. At no time did the vehicles have to deal with changing conditions.
Secondly, to my knowledge, there were no obstacles (which were promised) on the course. If someone knows differently, I'd like to hear about it. So we don't know to what extent obstacle avoidance is effective on those vehicles.
Thirdly, daylight and clear weather is one thing, but nighttime, rain, snow, etc. would significantly degrade the data.
Essentially the problem that the current vehicles solved was this:
Given a set of waypoints and a "corridor" outside which you will never have to go (so far the problem can be solved only by 10cm-accuracy DGPS), use your other sensors to avoid obstacles by moving left or right within the corridor.
Not very much like real world driving at all. And I'm not saying Stanford, CMU and the others didn't accomplish something big -- I'm just saying it's not what the Wired piece makes it out to be.
I personally prefer C#, at least as a toy language, for the following reasons:
*It has some features that make it more compact, like operator overloading.
*It is integrated into windows so you can make GUIs that look like other applications
*It is faster
*Visual studio is a better IDE than many of the Java ones
*All microsoft development tools are free to students.
Now all of these are explicitly whimsical arguments. In the real world, none of this matters, because the language you use in a given project will almost never be determined by pure aesthetics. But if you are going to spend a semester working with a language you never use again, I would rather spend it with C# than Java. And, as many have already said, they are so similar that you can pick up the other very quickly.
As another poster has pointed out, this is not a metal, but a ceramic that happens to contain aluminum. Which means it is not suitable for use in structural applications like airplane fuselages, or in foil. Also, metal's opaqueness to light and radio waves bears a direct relationship to its conductivity to electricity; in effect, metal "shorts out" an oncoming electromagnetic wave. There might be some exotic metals that are transparent. Since gold is so soft, it is relatively easy to hammer into sheets of only several atoms thick. It then becomes translucent. This of course was the reason why gold leaves were used to in the famous "plum pudding" experiment that proved the existence of a nucleus in atoms, but that is beside the point.
It wasn't so long ago, in the 70's, when books were being written to the effect that as population increases exponentially, we will by the late 1990's reach a Malthusian crisis with over 20 billion people on earth fighting over the last scraps of food. That didn't happen, and that's for a process that we KNOW grows exponentially (ie population). It just so happens that for a variety of factors (though generally not famine), the growth constant changed so that in many countries the population has levelled off.
Just because you can plot a few points in time and fit an exponential curve to them doesn't mean that it will continue to be an exponential curve forever. And I find Mr. Kurzweil's particular vision of the future somewhat offensive because it is a future that would only be imaginable or appealing to an American computer nerd.
The major concrete technical point made in this article is that the file system should be invisible to the user. This has been tried by literally dozens of groups and all of them have so far failed to produce something usable. Maybe when WinFS comes out it will change things. Steve Jobs and other people at Apple have been trying to erase the distinction between open files and saved files for years (it was done in the Newton) but it never caught on. So I think all these academics who advocate the same GUI innovations for 20 years in a row should
a) Try to make the innovations themselves and either succeed or prove to themselves why it's a bad idea
b) Think of a new GUI innovation that hasn't been beaten to death yet
So, I have a question actually relevant to this article. The article says that the CPU was supposed to jump to address FFFF_FFFF, turn off the ROM, then roll over to 0000_0000, where the CPU would throw an exception thus halting the CPU. However, says the article, the CPU does not in fact throw an exception in this case.
So my question is, how did the hackers who reverse engineered this code conclude that it was supposed to trigger an exception? It seems hard for me to believe that the MS engineers would base their entire security mechanism on a feature of the CPU that didn't actually exist.
I was proficient on QWERTY when I started using Dvorak. It took me about two weeks to adjust to using it on my computer. I've been using it for over a year and I still find it quite comfortable. After I switched I only used QWERTY keyboards occasionally, and at first I completely lost my typing skills to the point that it was as hard to type on QWERTY as it had been when I had never typed before. However within a few months I regained my QWERTY ability as well, so now I am pretty much equally good at QWERTY and Dvorak and have no problem switching back and forth. However I do still sometimes accidentally think that a key on a QWERTY kbd should be where it is on a Dvorak, but that's rare. So point is, if you can take a few weeks of slowed down typing, you'll be fine after that.
There are the ServView systems from BlackBox which are pretty much exactly what you are asking for, here is an image. They are made to be on slide-out drawers in a rackmount cabinet but you might be able to do some creative amputation to make it more portable :)
As some posts below reveal, the accident resulted from a series of mistakes/stupid actions. If any of these mistakes had not occurred, the accident would not have happened. The removal of the safeties in itself did not cause the accident - it was the raising of control rods, removal of cooling water, etc. Then because of the positive void coefficient, lowering the control rods briefly increased the power of the reactor and caused the explosion. Once the explosion happened, it was all over -- putting out the fire quickly was pretty hopeless once the graphite had caught on fire.
I read T3, the playboy for gadget lovers. They have a girl every month just like playboy except she's not naked and not all that hot. But when I read other magazines (Popular Science, Wired, etc), my favorite part is the new gadgets section anyway. T3 is one big gadgets section every month.
I use a TI-83 and to avoid parenthesizing I have been using the ANS button a lot, which essentially amounts to doing RPN. For example instead of 1/(5+3) I will do 5+3[Enter] 1/[Ans]. But I still find the ability to do algebraic notation useful for longer expressions when I would have too many things in the "stack".
I guess hydrologists just see the glass as half empty then . . .
I was unaware that housepaint is sold by the watt.
Because alcohol requires farming and farming requires gasoline. Alcohol prices are only low because gasoline prices are.
So if we accept that a planet is anything that has been rounded by its own gravity, we have to make assumptions about the density of the matter that it's made of. Stars that went through a supernova and no longer have enough mass to undergo fusion may be round and of comparable size to known planets, but many times denser. They clearly are not in fact planets but the author's criterion would have it that way. Of course we can say, "They aren't planets because they used to be stars" but he threw out the entire argument-from-origins criterion as being too difficult to establish.
Conveniently, he did not make a biological analogy for the argument-from-origins -- that is because biologically, it is the most sensible argument.
What he really did was shift the question from "how big do you have to be to be a planet" to "how dense do you have to be to be a planet." Now we have to establish an upper limit to planetary density, which is hard since it's hard to see small, dense objects.
Here are some of my bookmarks with photos of abandoned places . . . don't know how well any of them work:n /index. htmm lt tp://www.forgottendetroit.com/t en-ny.com/o logy.htmlw w.starfury.demon.co.uk/uground/m erica.com/lostframe.html. com/
http://detroityes.com/toc.htm#Gildedb ring.com/hub?ring=draining&list&page=1
http://members.tripod.com/airfields_freema
http://home2.planetinternet.be/henk/index.ht
http://www.columbia.edu/~brennan/abandoned/
h
http://www.forgot
http://www.acme.com/jef/photos/archae
http://www.infiltration.org/
http://w
http://www.losta
http://www.modern-ruins
http://www.losthighways.org/radebaugh.html
http://e.we
Regarding nuclear power, it is important to remember that uranium can run out just like fossil fuels, and in fact if we had started out using nuclear power instead of oil for energy, we would certainly have run out of nuclear fuel by now. In other words, nuclear power is not a solution except as a pollution free way to power a few dozen densely populated areas.
My view on the subject is, different groups will try to have a war in space. I don't know if it will be practical. We have already seen that the more modern two militaries are, the less willing they are to fight, because the hardware is just so expensive and the weapons so effective. Since WWII, there hasn't been a single war between two modern militaries with approximately equal capabilities. No two countries with nuclear weapons have fought, because again, there is no way to win when fighting with nuclear weapons.
Now, the cost of space hardware is high; stealth bombers are like peanuts compared to any imaginable space warship. And the physics are different -- since there is no drag in space, a very small projectile can do a whole lot of damage . And of course, if your entire ship weighs 10,000 pounds, you can't accelerate a 2,000 pound projectile, because you'll fly off in the opposite direction at a comparable speed.
And of course, how are you going to carry all that fuel in order to maneuver? Maybe when every spacecraft carries a fusion reactor onboard we can talk about space dogfights, but until then, it will be like the knight in Holy Grail trying to fight with no arms and no legs.
As for satellite weapons platforms, the solution is simple: bomb the mission control centers that are on the ground. That might happen. But that is not really war in space, that is a war over space.
A lot of people claim that the reason why the US doesn't use nuclear power everywhere is because of environmentalist whackos. This is not true. The reason is economics.
Back in the 50's when nuclear power was first proposed, people talked about having electricity too cheap to meter. The thing they did not consider is that a nuclear power plant costs much more to build than a coal/oil/natural gas plant. I want to make sure everyone understands why.
First of all, the radiation given off by fission destroys inorganic materials just as happily as it destroys human tissue. Very high quality metal must be used in all parts of the reactor to prevent degradation and to prevent it from becoming highly radioactive. This is even more of a problem in fusion reactors which have a much higher flow of neutrons, and in those, the only solution will be to replace the pieces every so often.
Second, the plant must be extremely highly reliable. One reason for this is draconian public safety regulations. However you have to keep in mind that even an accident that is contained within the plant and poses no risk to the public (a la Three Mile Island) can still destroy the reactor and put the plant out of commission.
This is true because of a property of the nuclear chain reaction. Dropping all of the control rods (scramming) does not instantly shut down the reaction in the way that dousing a coal fire would extinguish it. The reactor will continue to produce heat for around an hour after it is shut down. This means that it must be cooled for that hour, otherwise it will melt and flood the building with radioactive chemicals. The Chernobyl accident was caused by an attempt to test what happens if the cooling system is disabled.
So the system has to be very highly redundant, in part to protect the public, but mostly to protect the plant.
The last problem is that if the coolant is radioactive, you can't just call in a plumber to fix the leak as you might in a coal plant. See the movie K-19 Widowmaker for the effects of radioactive coolant on humans. You better make damn sure that system doesn't leak in the first place.
So the plants are expensive. This means you want economy of scale and build one large plant instead of many small ones. This means you don't want to build these plants in the Midwest where that much power just isn't useful. You want to build them near population centers. That explains why there is no nuclear power in sparsely populated places.
The other thing is that even though uranium is much cheaper than coal per joule (because you need so much less of it), the cost of the nuclear plant makes the whole process expensive enough that it has to compete with coal for the market. This means that in places where coal is cheap (as in the United States) building nuclear plants is only sensible up to a point. As the nuclear plants drive down demand for coal, the coal gets cheaper, so there is a natural feedback mechanism.
In the United States, we are a little bit below the optimal balance. We could economically build more nuclear plants but not that many. This difference is in part accounted for by the public perception of nuclear power.
It is also accounted for by the fact that it takes ten years to build a nuclear power plant, so if you have an energy crisis NOW, building a nuclear power plant is no good. California had to go with building natural gas power plants after their energy crisis because they are cheap and fast to build. Natural gas is more expensive but that's life.
Now it should be clear why France and Japan, two countries that use nuclear power for most of their needs, are able to do so while the US cannot. It has nothing to do with progressive governments or the lack of environmentalists. It is simply that France and Japan are small, densely populated countries (compared to the US) that have expensive coal (compared to the US). So they have a lot of nuclear plants (compared to the US).
I hope that explains a few things. Now as
Many of the posts so far have the attitude that there is an irrational fear of nuclear power and that the public is simply ignorant. There are a few points to counter that:
1)Many governments around the world, including the US government, put humans in unsafe radiation environments, which they knew to be unsafe, either to test the effect on the humans or because they didn't care. A significant number of people in the US military died because of this. There was a show on Nova about the Bikini Atoll nuclear tests, where the sailors watched the explosions from the decks of their ships. Many of those died.
You might say that this is all in the past, but look at how the Gulf War Syndrome patients have been treated by the US and UK governments. The symptoms are there, but nobody knows what causes them and so they just deny the effect and keep exposing more and more soldiers to whatever it is that causes the illness.
Look at how the US and UK governments deny the harmful effects of depleted uranium. DU munitions are not very radioactive, but the dust that is released when they burn finds its way into the human body very easily. Once inside, it can not only irradiate the body but also have other toxic effects associated with heavy metal. The military's OWN practice is aggressive decontamination of anything that is exposed to DU ash, but this is denied in official reports.
So in the absence of reliable independent reports, it is very difficult to accept these assertions of safety.
2)If only we had a way to quantify the danger posed by radiation we might not have this problem. However quantify it we cannot. Because of the random nature of radiation damage, it is very difficult to study. We know the effects of large doses fairly accurately but small doses require large population samples, and it is difficult to expose large populations to controlled doses of radiation.
The greatest danger posed by small radiation doses is genetic damage that can lead to cancer. We don't know how cancer works or how the human body normally prevents it. We don't know what enables humans to survive the genetic damage caused by the natural radiation environment. We can't even measure genetic damage. We know that USUALLY, small doses of radiation have no effect but don't know why SOMETIMES they do or what is a safe dose.
At its root, the fear of low level radiation is similar to the fear of other carcinogens. There is no way to quantify or track exposure because just ONE unlucky mutation could lead to a deadly cancer, but we have no idea which mutations these are or how to find them.
So what I would say is that those people who want to talk about irrational fears of the population should rationally counter some of these points. Most people who are pro-nuclear cannot counter them. They don't know anything about how radiation exposure is measured (except that it's in REMs), what the natural background radiation is in REMs, how many Curies are contained in coal ash, etc. etc. etc.
This is very similar to GM's HyWire concept car, which uses a motor on each wheel (though possibly not in-wheel, but still no gearbox in between). The HyWire is designed to run on fuel cells but any practical model would probably run a diesel engine also.
/ fuel_cell_innovation.html
This is GM's site: http://www.gm.com/automotive/innovations/Fuelcell
Again, city bus wheels are much heavier than regular car wheels. I think it might be possible for these motors to be reasonably close to the weight of a bus wheel's hub. Especially since according to the diagram, the wheel doesn't have a mechanical brake.
The reason why gas engines need transmissions is that gas engines run on a smaller range of RPM (revolutions per minute) than the wheel. For example a gas engine can't run below a few hundred RPM, so you need a clutch and a torque convertor to start the car moving from a stop. The engine also doesn't have enough torque to start the car moving from a stop so you need to gear it down. But by the time the car is moving a10 miles per hour, the geared-down engine is spinning at its limit, so you need another set of gears with a lower ratio to avoid revving the hell out of the engine . . . the top gear in most cars is 1:1 ratio, so when the motor is spinning at 2000 RPM, so are the shafts before the differential. In overdrive, the wheels actually spin faster than the engine, that's why it's called overdrive.
An electric motor runs fine at low RPMs all the way up to fairly high RPMs so you usually don't need a transmission, unless the motor doesn't have enough torque, in which case you need to gear it down but then can't go as fast. That's the basic reason why in-wheel motors are difficult -- the motor needs to be able to spin fast and still pack a punch.
You're neglecting the increase in the weight of the body due to batteries. Also, don't forget that the average city bus wheel hub already weighs quite a bit, and is made of steel. These motors probably have a lighter casing.
By this metric, A New Kind of Science gets:
10 points for claiming that your work is on the cutting edge of a "paradigm shift".
Number of Wolfram media appearances * (20 points for each favorable comparison of yourself to Newton)
50 points for claiming you have a revolutionary theory but giving no concrete testable predictions.
Finally, I can say what I think about it without knowing what the hell he's trying to prove!