So perhaps you'd like to explain what thermodynamic limits apply to regenerative braking?
First law - conservation of energy. You can't get any more energy back than there is kinetic energy of the car, but you can get arbitrarily close.
Second law - (roughly) no spontaneous entropy decreases in a closed system. Converting kinetic energy to electrical or chemical does not inherently involve entropy changes (chemical may, but it will be reversible).
There are some batteries that can charge quickly too, the problem is supplying a few thousand amps of current (for ~ 1 MW) - and that's going to be just as hard for capacitors.
Batteries also have a much higher energy density and can be (and almost always are) recycled.
The regenerative braking doesn't involve a heat engine, so in principle you could get arbitrarily close to 100% energy recovery given sufficiently advanced technology. IIRC, hybrids do get better range in urban driving.
Last time I checked the mpg ratings for UK cars, most automatics got significantly worse fuel economy than the manuals, by about 10%. Particularly Fords, oddly, perhaps they just make crappy gearboxes. Sometimes the automatic gets better, but not usually and even then it's only marginally.
Maybe these new dual clutch automatics will fix that, as there won't be the fluid losses in the torque converter.
The Mythbusters style drives me up the wall. Instead of having the myths presented in sequence, you have 2 minutes of one, switch to the next, two minutes of that, switch..... what the hell is all that for? Do they think viewers would get bored if they had to spend more than a couple of minutes on one subject? It made it extremely difficult to follow exactly what was going on.
No, the licence fee only applies if you use equipment to receive broadcasts - *owning* the equipment doesn't need a licence. So transferring from VHS to DVD via a TV card would be perfectly acceptable.
I remember when the Americans made a version of Scrapheap Challenge called Junkyard Wars, and the difference in style was very noticeable and grating - much more loud and obnoxious. But most British TV isn't so good these days - the comedy has been mostly dreadful for the past decade, with Peep Show being an honourable exception.
The BBC isn't "state run" really, and it *is* a good idea, particularly for news and current affairs, as it has much stronger requirements for balance and fairness than typical American commercial news stations (Fox News anyone?). It isn't just a government mouthpiece, if that's what you were worried about.
If you don't make quantitative predictions, you can surely rest easy in your beliefs because nothing can prove you wrong. Libertarians seem to have a nice trick for this - instead of treating certain results as good and justifying their theory on the basis that it produces these outcomes, they simply axiomatically state that free markets are always the best and therefore whatever economic situation results is the correct and just one, by definition.
It is somewhat analogous to the way the deeply religious operate - the ideas are so deeply embedded that evidence is simply twisted to fit in with them, or ignored if that really can't be done (e.g. evolution).
The fact that simple economic models can't predict everything is hardly a surprise - an economy is an extremely complex system. Frankly, the idea that a simple set of base assumptions can predict the best economic scenario is preposterous. Physicists don't claim that knowing the Schrodinger equation means you know all of chemistry automatically and don't need to do practical experiments, and an economy is much more complex than a molecule. Knowing the limits of your models is essential, and something that's obviously lacking in free-market fundamentalists.
The price thing is rather misleading. You can turn a ordinary PC into an acceptable gaming machine with a fairly low end graphics card, nowhere near the $300 you mention. How many people have a PS3 or Xbox 360 and don't have a PC?
I don't see the point in duplicating the CPU, motherboard, hard drive, etc. of my PC just so I can run one more type of application.
Joke? I've seen that advocated as a serious argument as to why tokamaks are a bad idea. I admit I didn't watch the clip, so maybe Bussard wasn't doing that, but others have.
Of course the mass has to be measured in your frame of reference. As we near the limit of the speed of light(for the exhaust) your reaction mass would start to increase and therefore its impulse would increase. However the reaction mass is stationary in our frame of reference before entering the engine and will therefore have rest mass. The effect being that there is no limit to specific impulse.
That makes sense, although it reinforces my belief that "relativistic mass" is confusing and pointless. There's no limit to the momentum with which a given amount of propellant can be ejected, providing some external energy source is provided, as momentum = gamma * mass * velocity.
If you can only use what you can carry as an energy source, the best you can do with the mass you can carry is what I said - carry antimatter, annihilate it down to massless particle such as photons and use those annihilation products as propellant. We're a long way from being able to do that though.
The maximum would be if you had matter/antimatter fuel, and somehow reflected the annihilation photons all in the thrust direction. The specific impulse then would be 30 million seconds (photon energy = mc^2, photon momentum = E/c, therefore impulse = mc and specific impulse = mc / mg = 3e7 seconds. m here refers to mass of fuel.).
Mass is an invariant, it doesn't increase with speed. "Relativistic mass" isn't really helpful, as a concept, as it leads to confusion - if what you said was true, the usable energy in the fuel would be frame-of-reference dependent, which doesn't make a lot of sense.
I'll rephrase the last part of my statement for clarity: "... then that eradication is morally right?"
Do I think so? No, but that wouldn't stop it happening if enough people wanted it to. While I don't think murder is morally acceptable, I can't provide a fundamental reason for that belief - I consider it axiomatic. I just wish everyone else were as realistic about the limitations of their philosophy.
The fact that some people commit murders is not evidence that murder is morally right. By the same logic, the fact that people's rights are often violated is not evidence that they don't have those rights.
No, but it is evidence that rights are not something fundamental to the universe, but instead reliant on active enforcement. Things which are fundamental and independent of human society, such as the laws of physics, cannot be violated even if everyone agrees to. People's rights, on the other hand, can, suggesting that they are not in fact fundamental and the whole concept of "natural" rights is a bit silly, really.
OK, I'll rephrase. What right do I have to force people to recognise that money as "mine" for the purposes of conducting transactions?
Your second point is asserted, not justified, and in any case is debatable. If someone has a monopoly in a service essential to life, I have no choice and he can charge whatever he likes. That's no more voluntary than holding a gun to my head and demanding my money.
Real scenarios are not so black and white, of course. But "voluntary" is misleading - it's always subject to conditions. What I'd voluntarily agree to under conditions A is not the same as under conditions B. Exactly which conditions apply depend on the law, which is where we started.
So, if 'society' decides that we should no longer speak freely, that right disappears. And finally, if I can get 'society' to think that we should all have the right to kill off a particular group, or anything else abhorrent, then that's all fine and dandy?
Regrettably, yes. What do *you* think would happen? It may not be "fine and dandy" my your or my standards, but it would happen nevertheless.
This has happened on many occasions, which should provide some evidence against the "fundamental rights" theory. I fear people are confusing what they wish would be the case with what actually is.
Not sure why you'd think I was trolling, I genuinely believe what I said.
The reasons for such service obligations are that it's becoming increasingly difficult to take part in normal life and society without that service, perhaps because so many important services and information sources are online. If entire areas are unable to access these, it will have a negative effect on the viability of that segment of society.
However, all of these that can be done with 1Mbps, except for the telecommuting that jhol13 mentions below, which I hadn't thought of.
Well, yes I've been deprived of what I could have spent the money on. But that assumes that I had a right to demand those goods and services in the first place. I'm being deprived right now of plenty of things I might want but can't afford, but since most people would say I don't have a right to them, that's not a problem.
By what fundamental process can we establish exactly what I *am* entitled to? If I do work X, why am I entitled to Y compensation rather than Y+a or Y-a? Not a trivial question by any means, and historically there's been much argument over it, often prompted by clear examples of exploitation of workers.
I don't think I misunderstand the argument, I just disagree with it. I didn't used to, but after a while came to the conclusion that it was flawed, and has too many implicit assumptions which are problematic. To say that tax is not justified regardless of its purpose requires that a) property is more important than any other right and b) the pre-tax amount of money is exactly the morally justified amount that the person is entitled to as his property. I think that a) is just plain wrong and b) is not proven in general, and clearly untrue in some cases.
Sure, if I'm legally prohibited from stopping you then you do indeed have a practical right to free speech. But if you're legally prohibited from stopping me then I could simply walk up and take your money. That doesn't mean I have a fundamental *right* to. It's all dependent on what the government will back you up on, and how do we decide on what that should be? "Legal consequences" implies some kind of government structure to enforce them.
Ultimately, what's considered a right comes down to under what circumstances people are allowed to hit you over the head. If I have a right to free speech, you're not allowed to harm me to stop me exercising it. If I have a right to health care, you're not allowed to use force to deny me the resources to achieve it, even if you consider them your property. Etc...
Sadly, there are no natural laws of rights, just laws of physics. Everything else is artificial.
Well, yes I can imagine that. But that's isn't exactly something so essential that it needs to be subsidised by the rest of society. Things like access to important information and services, www browsing, email, VoIP, video communication, online shopping and other commercial activity, participation in government etc. can be done over 1 Mbps.
In fact, my current connection is a whopping 1.5 Mbps (long phone line) and to be honest I don't notice much difference from my previous 10 Mbps one in practice. Not that I'd turn down a faster connection, but it's really not that big a deal.
They aren't. I've never been forced to help anyone, for example. If you're referring to taxes, that's simply society not recognising your right to that money, and by your own arguments they can't be *forced* to...
Free speech requires that people tolerate your speech, rather than say bash you over the head with the nearest object. Now that may indeed by a *justifiable* restriction on other people, but it's a restriction nevertheless. In fact, since actually enforcing this requires a police force and justice system, it's even an imposition on the general taxpayer.
Consequence, imposition. You say potato... Being shot sounds like a pretty severe imposition to me. Having to pay taxes is just a consequence, too, if you want to define it like that.
Now, I'm not saying that an internet connection should be a right. But there's no *fundamental* distinction.
Slashdot Mirror
So perhaps you'd like to explain what thermodynamic limits apply to regenerative braking?
First law - conservation of energy. You can't get any more energy back than there is kinetic energy of the car, but you can get arbitrarily close.
Second law - (roughly) no spontaneous entropy decreases in a closed system. Converting kinetic energy to electrical or chemical does not inherently involve entropy changes (chemical may, but it will be reversible).
So, where does the inevitable loss come in then?
There are some batteries that can charge quickly too, the problem is supplying a few thousand amps of current (for ~ 1 MW) - and that's going to be just as hard for capacitors.
Batteries also have a much higher energy density and can be (and almost always are) recycled.
The regenerative braking doesn't involve a heat engine, so in principle you could get arbitrarily close to 100% energy recovery given sufficiently advanced technology. IIRC, hybrids do get better range in urban driving.
Last time I checked the mpg ratings for UK cars, most automatics got significantly worse fuel economy than the manuals, by about 10%. Particularly Fords, oddly, perhaps they just make crappy gearboxes. Sometimes the automatic gets better, but not usually and even then it's only marginally.
Maybe these new dual clutch automatics will fix that, as there won't be the fluid losses in the torque converter.
The Mythbusters style drives me up the wall. Instead of having the myths presented in sequence, you have 2 minutes of one, switch to the next, two minutes of that, switch..... what the hell is all that for? Do they think viewers would get bored if they had to spend more than a couple of minutes on one subject? It made it extremely difficult to follow exactly what was going on.
No, the licence fee only applies if you use equipment to receive broadcasts - *owning* the equipment doesn't need a licence. So transferring from VHS to DVD via a TV card would be perfectly acceptable.
I remember when the Americans made a version of Scrapheap Challenge called Junkyard Wars, and the difference in style was very noticeable and grating - much more loud and obnoxious. But most British TV isn't so good these days - the comedy has been mostly dreadful for the past decade, with Peep Show being an honourable exception.
The BBC isn't "state run" really, and it *is* a good idea, particularly for news and current affairs, as it has much stronger requirements for balance and fairness than typical American commercial news stations (Fox News anyone?). It isn't just a government mouthpiece, if that's what you were worried about.
If you don't make quantitative predictions, you can surely rest easy in your beliefs because nothing can prove you wrong. Libertarians seem to have a nice trick for this - instead of treating certain results as good and justifying their theory on the basis that it produces these outcomes, they simply axiomatically state that free markets are always the best and therefore whatever economic situation results is the correct and just one, by definition.
It is somewhat analogous to the way the deeply religious operate - the ideas are so deeply embedded that evidence is simply twisted to fit in with them, or ignored if that really can't be done (e.g. evolution).
The fact that simple economic models can't predict everything is hardly a surprise - an economy is an extremely complex system. Frankly, the idea that a simple set of base assumptions can predict the best economic scenario is preposterous. Physicists don't claim that knowing the Schrodinger equation means you know all of chemistry automatically and don't need to do practical experiments, and an economy is much more complex than a molecule. Knowing the limits of your models is essential, and something that's obviously lacking in free-market fundamentalists.
The price thing is rather misleading. You can turn a ordinary PC into an acceptable gaming machine with a fairly low end graphics card, nowhere near the $300 you mention. How many people have a PS3 or Xbox 360 and don't have a PC?
I don't see the point in duplicating the CPU, motherboard, hard drive, etc. of my PC just so I can run one more type of application.
Joke? I've seen that advocated as a serious argument as to why tokamaks are a bad idea. I admit I didn't watch the clip, so maybe Bussard wasn't doing that, but others have.
Of course the mass has to be measured in your frame of reference. As we near the limit of the speed of light(for the exhaust) your reaction mass would start to increase and therefore its impulse would increase. However the reaction mass is stationary in our frame of reference before entering the engine and will therefore have rest mass. The effect being that there is no limit to specific impulse.
That makes sense, although it reinforces my belief that "relativistic mass" is confusing and pointless. There's no limit to the momentum with which a given amount of propellant can be ejected, providing some external energy source is provided, as momentum = gamma * mass * velocity.
If you can only use what you can carry as an energy source, the best you can do with the mass you can carry is what I said - carry antimatter, annihilate it down to massless particle such as photons and use those annihilation products as propellant. We're a long way from being able to do that though.
The maximum would be if you had matter/antimatter fuel, and somehow reflected the annihilation photons all in the thrust direction. The specific impulse then would be 30 million seconds (photon energy = mc^2, photon momentum = E/c, therefore impulse = mc and specific impulse = mc / mg = 3e7 seconds. m here refers to mass of fuel.).
Mass is an invariant, it doesn't increase with speed. "Relativistic mass" isn't really helpful, as a concept, as it leads to confusion - if what you said was true, the usable energy in the fuel would be frame-of-reference dependent, which doesn't make a lot of sense.
"100 billion stars in the sky and not one is toroidal"
That's an odd argument. No animal has wheels, but that doesn't mean that it would be sensible to build a car with legs.
I'll rephrase the last part of my statement for clarity: "... then that eradication is morally right?"
Do I think so? No, but that wouldn't stop it happening if enough people wanted it to. While I don't think murder is morally acceptable, I can't provide a fundamental reason for that belief - I consider it axiomatic. I just wish everyone else were as realistic about the limitations of their philosophy.
The fact that some people commit murders is not evidence that murder is morally right. By the same logic, the fact that people's rights are often violated is not evidence that they don't have those rights.
No, but it is evidence that rights are not something fundamental to the universe, but instead reliant on active enforcement. Things which are fundamental and independent of human society, such as the laws of physics, cannot be violated even if everyone agrees to. People's rights, on the other hand, can, suggesting that they are not in fact fundamental and the whole concept of "natural" rights is a bit silly, really.
Sure, today an efficient TV, tomorrow concentration camps....
+4 Insightful? Really?
Why don't you define them, instead of resorting to abuse as a substitute for argument? I notice you didn't actually address any of my points.
I'm pretty sure you didn't learn about a current of magnetic monopoles in electromagnetics class.
This is not the same as a normal current of electric monopoles (charges) producing a magnetic field.
OK, I'll rephrase. What right do I have to force people to recognise that money as "mine" for the purposes of conducting transactions?
Your second point is asserted, not justified, and in any case is debatable. If someone has a monopoly in a service essential to life, I have no choice and he can charge whatever he likes. That's no more voluntary than holding a gun to my head and demanding my money.
Real scenarios are not so black and white, of course. But "voluntary" is misleading - it's always subject to conditions. What I'd voluntarily agree to under conditions A is not the same as under conditions B. Exactly which conditions apply depend on the law, which is where we started.
So, if 'society' decides that we should no longer speak freely, that right disappears. And finally, if I can get 'society' to think that we should all have the right to kill off a particular group, or anything else abhorrent, then that's all fine and dandy?
Regrettably, yes. What do *you* think would happen? It may not be "fine and dandy" my your or my standards, but it would happen nevertheless.
This has happened on many occasions, which should provide some evidence against the "fundamental rights" theory. I fear people are confusing what they wish would be the case with what actually is.
Not sure why you'd think I was trolling, I genuinely believe what I said.
The reasons for such service obligations are that it's becoming increasingly difficult to take part in normal life and society without that service, perhaps because so many important services and information sources are online. If entire areas are unable to access these, it will have a negative effect on the viability of that segment of society.
However, all of these that can be done with 1Mbps, except for the telecommuting that jhol13 mentions below, which I hadn't thought of.
Well, yes I've been deprived of what I could have spent the money on. But that assumes that I had a right to demand those goods and services in the first place. I'm being deprived right now of plenty of things I might want but can't afford, but since most people would say I don't have a right to them, that's not a problem.
By what fundamental process can we establish exactly what I *am* entitled to? If I do work X, why am I entitled to Y compensation rather than Y+a or Y-a? Not a trivial question by any means, and historically there's been much argument over it, often prompted by clear examples of exploitation of workers.
I don't think I misunderstand the argument, I just disagree with it. I didn't used to, but after a while came to the conclusion that it was flawed, and has too many implicit assumptions which are problematic. To say that tax is not justified regardless of its purpose requires that a) property is more important than any other right and b) the pre-tax amount of money is exactly the morally justified amount that the person is entitled to as his property. I think that a) is just plain wrong and b) is not proven in general, and clearly untrue in some cases.
Sure, if I'm legally prohibited from stopping you then you do indeed have a practical right to free speech. But if you're legally prohibited from stopping me then I could simply walk up and take your money. That doesn't mean I have a fundamental *right* to. It's all dependent on what the government will back you up on, and how do we decide on what that should be? "Legal consequences" implies some kind of government structure to enforce them.
Ultimately, what's considered a right comes down to under what circumstances people are allowed to hit you over the head. If I have a right to free speech, you're not allowed to harm me to stop me exercising it. If I have a right to health care, you're not allowed to use force to deny me the resources to achieve it, even if you consider them your property. Etc...
Sadly, there are no natural laws of rights, just laws of physics. Everything else is artificial.
Well, yes I can imagine that. But that's isn't exactly something so essential that it needs to be subsidised by the rest of society. Things like access to important information and services, www browsing, email, VoIP, video communication, online shopping and other commercial activity, participation in government etc. can be done over 1 Mbps.
In fact, my current connection is a whopping 1.5 Mbps (long phone line) and to be honest I don't notice much difference from my previous 10 Mbps one in practice. Not that I'd turn down a faster connection, but it's really not that big a deal.
They aren't. I've never been forced to help anyone, for example. If you're referring to taxes, that's simply society not recognising your right to that money, and by your own arguments they can't be *forced* to...
Free speech requires that people tolerate your speech, rather than say bash you over the head with the nearest object. Now that may indeed by a *justifiable* restriction on other people, but it's a restriction nevertheless. In fact, since actually enforcing this requires a police force and justice system, it's even an imposition on the general taxpayer.
Consequence, imposition. You say potato... Being shot sounds like a pretty severe imposition to me. Having to pay taxes is just a consequence, too, if you want to define it like that.
Now, I'm not saying that an internet connection should be a right. But there's no *fundamental* distinction.