The Prius's transmission ("Synergy Drive") is freaking *weird*, and well worth reading about if you're an engineering fan. It's not a traditional automatic, it's not a traditional CVT, it's totally different from anything else on the road today.
As for "throttle and transmission don't coordinate their actions", both power sources (electric motor and IC engine) and the linkage between them are under computer control, and the gas pedal is really just a user interface device: the driver can say "I want to go faster", but exactly how that happens is up to the computer.
Woz's point (and mine) is that the whole power system on a Prius is software-controlled, and problems with it are likely to be software bugs rather than simple mechanical limitations.
1) What matters is not the energy stored in the fuel, but the energy delivered to the wheels. Since liquid fuel motors are about 3x less efficient than electric, my "factor of 45" drops to a factor of 15.
2) We should be considering total power system mass, not just energy-storage-system mass. True, but *because* batteries have such low energy density, they account for the bulk of the power system mass for current electric vehicles.
So making these corrections, we still find that electric power systems are an order of magnitude "worse" than liquid fuels.
3) People don't *need* the amount of power and range they currently get with their current liquid-fueled vehicles: an electric vehicle will suffice for the majority of the population.
Point 3 is absolutely right, but naive. One look at the vehicles in the parking lot outside your building will convince you that people don't buy the vehicles they *need*: if they did, they'd all be driving Civics, Hyundais and SMART cars instead of BMWs and Escalades. If you offer the average customer two vehicles at similar prices, one with 10 times the range and/or power of the other, he or she will choose the more powerful one almost every time.
I never said that electric vehicles are not a workable transportation option: I said they [b]cannot compete[/b] against liquid fuel vehicles in an open market.
As some of you noticed, I left some openings in my argument: if liquid fuels become prohibitively expensive due to supply shortage or taxes, or if taxes, credits, or other laws drive the customer's choice, electric vehicles may become a good option for the average joe.
So no gain there: electric motors weigh about the same as a similar-power gasoline engine.
Liquid fuel engines are about 30% efficient; electric motors are about 90% efficient. So that gains you a factor of 3...
So correcting for your objections, we find that gasoline fuel provides *15* times as much energy delivered per storage mass.
Your one remaining point, that what matters is the *total* power system mass, not just the weight of fuel, also doesn't make a big difference. The Chevy Volt's motor mass is negligible compared to the mass of its batteries.
So, I said batteries are 45 times worse than gasoline, with your correction it's only 15 times worse, but I think my point still stands.
As for the potential for future improvement, energy density of batteries has improved by a factor of 4 from lead-acid to lithium-ion... and it only took a century to get there!
I'm gonna go out on a limb here and say that the Model S will fail not because Tesla Motors is staffed by idiots (it isn't), and not because the gubmint won't support electric vehicles, but because fully electric vehicles cannot be competitive with liquid-fuel vehicles.
Forget unit prices, horsepower, yadda yadda, here's the only statistic that matters:
Energy density of lithium batteries: 1 megajoule/kg Energy density of gasoline: 45 megajoules/kg
Vehicles are unique among energy technologies in that they typically have to carry their energy source around with them. So energy stored per mass is the most important figure of merit for vehicle propulsion, and electric vehicles are inherently 45 times worse than their liquid-fuel competition.
To compensate for that factor of 45, serious sacrifices have to be made: either you accept a huge reduction in vehicle range, a huge reduction in vehicle performance, or you spend ridiculous amounts of money reducing drag and friction -- spending that shows up in the final price of the vehicle.
I predict that electric vehicles will never be able to overcome the energy density barrier and become popular, until either liquid fuel is no longer a readily available competitor, or vehicles no longer have to carry their own energy supply (think electric trains.)
And if you think you'll be able to convince the public to stop using gasoline "for the good of the planet", or for any reason other than prohibitive cost, I think you're probably naive. I've been trying to think of times when humans gave up an energy source for any reason other than cost vs performance. The only example I can think of is human slavery, and we had to destroy half of a nation to convince them to give it up.
Brilliant. This is such a good idea it's gotta be true. And I'm sure $400K is exactly the same amount charged by some RIAA team for some previous case.
Best part is: if the judge decides that $400K is unreasonable, they can use that precedent in the future. If the judge decides it isn't, the EFF gets 400 grand.
1. Privacy does not exist for WoW characters. Any other WoW player can see what your character is doing at any time, using in-game tools. Nothing new is gained from the Armory info. "Stalking" a character using the Armory is useless, since you could do it in-game just as easily.
2. The Armory gives no data to connect your WoW activities to your real life. "Stalking" a person in real life through the Armory is impossible, since you can't connect a person to their character.
The only real-life risk is if someone has information to connect your character to your real life. Then you've got potential stalker problems, potential home invasion problems, potential employer problems, potential relationship problems. But that connecting information was given away by YOU. Blizzard is not to blame, YOU are.
If you don't want your real life to cross over with your online activities, don't connect the two. Only a few close friends and family know I play a lot of WoW. Only my wife knows the name of my server, my guild, and my characters -- and that's only because she plays with me. My work e-mail contains no trace of WoW. Contrariwise, some of my closer WoW friends know what part of the country I live in and what type of work I do, but none could identify my town of residence or my employer. A few have a Gmail address for me which is used only for gaming activities. Only two know my real name.
Whenever you're tempted to let your online personas cross over into your real life, or just interconnect with each other, remember the story of the little Dutch boy and the dike.
I'm not sure if you're pulling a clever troll, or just having Turing test issues.
Which is more likely: an AI designed to behave appropriately in every 5-man dungeon in WOTLK (including the dragonflying in Oculus, the weird platform jumps in Nexus, the jousting in ToC...), or that WoW has some players who are either really terrible or who just don't care?
The solution's the same either way: vote to kick. But I've met a lot of humans who'd fail a Turing test.
Absolutely not. He only mentioned an urge to sneeze, nothing about severe pain, funny-colored urine, blisters, dead skin, etc.
I have exactly the same symptom he does, and given the amount of time I spent in the sun as a kid growing up in Hawaii, if it was porphyria I'd probably be dead.
Anyway, the photic sneeze reflex occurs in 18-35% of the population, while porphyria is incredibly rare. Didn't they teach you something about hoofbeats and zebras in med school?
In the 1930s, a kid's modest future was all planned out for him/her. If you were a girl, get married. If a boy, work in a factory or on the farm, go into your father's business, by your teens you knew where you were headed.
Today we teach kids that the sky's the limit, and they can do anything. Which makes them unrealistically optimistic, and leads to anxiety when they figure out that while *somebody* gets to be president, it's not going to be them.
Facebook is designed from the ground up to be nonprivate. Since it doesn't allow you to distinguish between "work friends" and "party friends" and "closet friends", anyone with a brain will only post lowest-common-denominator acceptable comments to FB. If everyone is treating Facebook that way, there's no benefit to be gained by adding privacy to interactions that are already self-sanitized.
But there are *plenty* of social interactions that *do* require an expectation of privacy, ranging from private sexual lives to the mere fact that I don't want my work colleagues to know about my Warcraft friends, or vice versa. But Zuckerberg doesn't see these sides of people, because they're not on Facebook.
Jumping from "Facebook interactions don't need privacy" to "our society doesn't need privacy" is a fallacy of composition.
This is what happens when you start taking anthropomorphism seriously. You get grand-sounding philosophical statements ("Matter has a mission", "nature abhors a vacuum", "information wants to be free" (woot flamebait!)) which have no basis in fact (see Magsol's spot-on reply in this thread).
No, it works in a evolution sense too. Machines exist in an environment which is hostile to "broken" machines. It just so happens that their survival and reproduction is mediated by an intelligent agent, but the process is the same.
Domesticated animals follow the same pattern. They're evolving within an environment whose rules of survival are set by humans. Humans didn't "intelligently design" cows, in the sense of directly choosing specific mutations to lactation hormone receptors, we just set up a selection environment in which only the cows that produce the most milk reproduce.
Darwin himself recognized the connection here. His book takes as a given that evolution (defined as gradual change in organisms) obviously exists, and asks "how?" He starts by laying out how domesticated organisms evolve via "artificial selection" by humans. Then he argues that wild organisms must operate by the same mechanism, except that reproduction depends on natural rather than manmade pressures -- therefore "natural selection".
The confusion in this thread is over the distinction between "evolution", which was patently obvious to every biologist in Darwin's time, and "evolution by natural selection", which was not.
Yes, the plants tend to be dry, oily, and highly flammable, with fire-resistant seeds. In the U.S., manzanita and similar plants are thought to do the same thing.
However, this has no bearing on whether fire is alive. Symbiosis is not a requirement of life, but (I think) evolution by natural selection is. Fire doesn't contain information about itself -- its properties are only a function of its fuel. It's not like lighting paper with a match produces a different fire than lighting it with a candle. Fire doesn't undergo natural selection, except in the trivial sense that big fires are harder to put out.
Clever, but misleading (whether or not it was intended as a joke).
Darwin's theory of natural selection requires an entity to store the information needed to make *more* of itself. You can't make more matter -- at least, not without making an equal amount of antimatter -- so no natural selection is possible.
Darwin of course knew nothing of DNA, and his theory of evolution says nothing about it. Darwin didn't put it this way, but the key requirements for an entity to evolve are:
1. The entity contains the information needed to replicate (self-description) 2. This information is subject to random changes (mutation) 3. The environment is hostile -- some but *not all* entities will be destroyed (survival) 4. Variations between individuals make them more or less likely to survive (fitness)
DNA-based life fits these restrictions, but so do entities which store their self-descriptive information in RNA, protein, or computer memory. It places no restrictions whatever on the existence of life chemistry based around other atoms than carbon.
You can make lots of chemistry arguments about why carbon is necessary, but you can't argue it on pure Darwinian grounds. As for your specific point in favor of carbon:
Carbon has lots of free valences, which allow it to act like a universal lego-block
Silicon has the same valence properties, and also forms a wide variety of complex molecules. Phosphorus and sulfur can have valences of 5 or 6 in certain situations. Now, carbon *is* special, but not in the way you've described.
So what, a keychain fob is going to suddenly stop working if it gets near a Linux device? Open source is a powerful thing, but if it now has an aura that destroys all non-GPL devices in a ten foot radius, I'm really impressed.
Also, "thousands of you" means there are as many of you as there are level 80 female dwarf subtlety rogues wielding Quel'dalar. You'd be insignificant even if you *did* all quit the game rather than play on another platform... which you won't.
Direct solar thermal plants need an insane amount of plumbing and a zillion little motors to run the heliostats to point the mirrors at the sun.
This updraft machine is definitely going to have lower thermodynamic efficiency (Carnot's law guarantees it), but on the other hand it has far fewer moving parts.
Direct solar thermal plants need an insane amount of plumbing and a zillion little motors to run the heliostats to point the mirrors at the sun.
This updraft machine is definitely going to have lower thermodynamic efficiency (Carnot's law guarantees it), but on the other hand it has far fewer moving parts.
for model planes they were totally impractical just a few years ago.
Not true anymore. One of the side effects of the cell phone revolution is that their high-tech batteries and the micro-motors that make the phone vibrate allow you to build some great electric aircraft.
For a 200-kg copter, 30-40 kW sounds about right from my calculations too. Your average top-of-the-line Li-ion battery has a specific power density of 1000 W/kg and 200 W-h/kg: 40 kg of batteries would give you enough power to lift off and 12 minutes of flight time.
Now, the only problem is fitting four electric motors with 13 horsepower each, power electronics, and a carbon composite frame into the remaining 60 kg...
Oh, and figuring out how to not die when the batteries run out.
Slashdot Mirror
The Prius's transmission ("Synergy Drive") is freaking *weird*, and well worth reading about if you're an engineering fan. It's not a traditional automatic, it's not a traditional CVT, it's totally different from anything else on the road today.
As for "throttle and transmission don't coordinate their actions", both power sources (electric motor and IC engine) and the linkage between them are under computer control, and the gas pedal is really just a user interface device: the driver can say "I want to go faster", but exactly how that happens is up to the computer.
Woz's point (and mine) is that the whole power system on a Prius is software-controlled, and problems with it are likely to be software bugs rather than simple mechanical limitations.
"lower gear"? Clearly you've never driven a Prius. A Prius don't have gears.
To summarize responses to my original post:
1) What matters is not the energy stored in the fuel, but the energy delivered to the wheels. Since liquid fuel motors are about 3x less efficient than electric, my "factor of 45" drops to a factor of 15.
2) We should be considering total power system mass, not just energy-storage-system mass. True, but *because* batteries have such low energy density, they account for the bulk of the power system mass for current electric vehicles.
So making these corrections, we still find that electric power systems are an order of magnitude "worse" than liquid fuels.
3) People don't *need* the amount of power and range they currently get with their current liquid-fueled vehicles: an electric vehicle will suffice for the majority of the population.
Point 3 is absolutely right, but naive. One look at the vehicles in the parking lot outside your building will convince you that people don't buy the vehicles they *need*: if they did, they'd all be driving Civics, Hyundais and SMART cars instead of BMWs and Escalades. If you offer the average customer two vehicles at similar prices, one with 10 times the range and/or power of the other, he or she will choose the more powerful one almost every time.
I never said that electric vehicles are not a workable transportation option: I said they [b]cannot compete[/b] against liquid fuel vehicles in an open market.
As some of you noticed, I left some openings in my argument: if liquid fuels become prohibitively expensive due to supply shortage or taxes, or if taxes, credits, or other laws drive the customer's choice, electric vehicles may become a good option for the average joe.
Specific power of an IC engine: around 2 kW/kg
Specific power of an electric motor: around 2 kW/kg
http://en.wikipedia.org/wiki/Power-to-weight_ratio
So no gain there: electric motors weigh about the same as a similar-power gasoline engine.
Liquid fuel engines are about 30% efficient; electric motors are about 90% efficient. So that gains you a factor of 3...
So correcting for your objections, we find that gasoline fuel provides *15* times as much energy delivered per storage mass.
Your one remaining point, that what matters is the *total* power system mass, not just the weight of fuel, also doesn't make a big difference. The Chevy Volt's motor mass is negligible compared to the mass of its batteries.
So, I said batteries are 45 times worse than gasoline, with your correction it's only 15 times worse, but I think my point still stands.
As for the potential for future improvement, energy density of batteries has improved by a factor of 4 from lead-acid to lithium-ion ... and it only took a century to get there!
I'm gonna go out on a limb here and say that the Model S will fail not because Tesla Motors is staffed by idiots (it isn't), and not because the gubmint won't support electric vehicles, but because fully electric vehicles cannot be competitive with liquid-fuel vehicles.
Forget unit prices, horsepower, yadda yadda, here's the only statistic that matters:
Energy density of lithium batteries: 1 megajoule/kg
Energy density of gasoline: 45 megajoules/kg
Vehicles are unique among energy technologies in that they typically have to carry their energy source around with them. So energy stored per mass is the most important figure of merit for vehicle propulsion, and electric vehicles are inherently 45 times worse than their liquid-fuel competition.
To compensate for that factor of 45, serious sacrifices have to be made: either you accept a huge reduction in vehicle range, a huge reduction in vehicle performance, or you spend ridiculous amounts of money reducing drag and friction -- spending that shows up in the final price of the vehicle.
I predict that electric vehicles will never be able to overcome the energy density barrier and become popular, until either liquid fuel is no longer a readily available competitor, or vehicles no longer have to carry their own energy supply (think electric trains.)
And if you think you'll be able to convince the public to stop using gasoline "for the good of the planet", or for any reason other than prohibitive cost, I think you're probably naive. I've been trying to think of times when humans gave up an energy source for any reason other than cost vs performance. The only example I can think of is human slavery, and we had to destroy half of a nation to convince them to give it up.
Brilliant. This is such a good idea it's gotta be true. And I'm sure $400K is exactly the same amount charged by some RIAA team for some previous case.
Best part is: if the judge decides that $400K is unreasonable, they can use that precedent in the future. If the judge decides it isn't, the EFF gets 400 grand.
1. Privacy does not exist for WoW characters. Any other WoW player can see what your character is doing at any time, using in-game tools. Nothing new is gained from the Armory info. "Stalking" a character using the Armory is useless, since you could do it in-game just as easily.
2. The Armory gives no data to connect your WoW activities to your real life. "Stalking" a person in real life through the Armory is impossible, since you can't connect a person to their character.
The only real-life risk is if someone has information to connect your character to your real life. Then you've got potential stalker problems, potential home invasion problems, potential employer problems, potential relationship problems. But that connecting information was given away by YOU. Blizzard is not to blame, YOU are.
If you don't want your real life to cross over with your online activities, don't connect the two. Only a few close friends and family know I play a lot of WoW. Only my wife knows the name of my server, my guild, and my characters -- and that's only because she plays with me. My work e-mail contains no trace of WoW. Contrariwise, some of my closer WoW friends know what part of the country I live in and what type of work I do, but none could identify my town of residence or my employer. A few have a Gmail address for me which is used only for gaming activities. Only two know my real name.
Whenever you're tempted to let your online personas cross over into your real life, or just interconnect with each other, remember the story of the little Dutch boy and the dike.
I'm not sure if you're pulling a clever troll, or just having Turing test issues.
Which is more likely: an AI designed to behave appropriately in every 5-man dungeon in WOTLK (including the dragonflying in Oculus, the weird platform jumps in Nexus, the jousting in ToC...), or that WoW has some players who are either really terrible or who just don't care?
The solution's the same either way: vote to kick. But I've met a lot of humans who'd fail a Turing test.
We're trying to play a fantasy game here, not Robot Battle.
Absolutely not. He only mentioned an urge to sneeze, nothing about severe pain, funny-colored urine, blisters, dead skin, etc.
I have exactly the same symptom he does, and given the amount of time I spent in the sun as a kid growing up in Hawaii, if it was porphyria I'd probably be dead.
Anyway, the photic sneeze reflex occurs in 18-35% of the population, while porphyria is incredibly rare. Didn't they teach you something about hoofbeats and zebras in med school?
I have an alergy to sunlight ... when I mentioned to a professional, apparently it's common but not normal and has been diagnosed as an alergy.
No you don't. Get a better professional, or at least spend thirty seconds Googling it.
It's a common genetic condition, probably related to some sort of signal crosstalk between the optic nerve and the nerve that causes sneezes.
http://en.wikipedia.org/wiki/Photic_sneeze_reflex
http://www.straightdope.com/columns/read/527/why-do-some-people-sneeze-when-going-out-into-bright-light
Simple explanation: we lie to our kids.
In the 1930s, a kid's modest future was all planned out for him/her. If you were a girl, get married. If a boy, work in a factory or on the farm, go into your father's business, by your teens you knew where you were headed.
Today we teach kids that the sky's the limit, and they can do anything. Which makes them unrealistically optimistic, and leads to anxiety when they figure out that while *somebody* gets to be president, it's not going to be them.
"anxiety and unrealistic optimism"
Congrats, psychologists. You've just defined the modern teenager.
Facebook is designed from the ground up to be nonprivate. Since it doesn't allow you to distinguish between "work friends" and "party friends" and "closet friends", anyone with a brain will only post lowest-common-denominator acceptable comments to FB. If everyone is treating Facebook that way, there's no benefit to be gained by adding privacy to interactions that are already self-sanitized.
But there are *plenty* of social interactions that *do* require an expectation of privacy, ranging from private sexual lives to the mere fact that I don't want my work colleagues to know about my Warcraft friends, or vice versa. But Zuckerberg doesn't see these sides of people, because they're not on Facebook.
Jumping from "Facebook interactions don't need privacy" to "our society doesn't need privacy" is a fallacy of composition.
This is what happens when you start taking anthropomorphism seriously. You get grand-sounding philosophical statements ("Matter has a mission", "nature abhors a vacuum", "information wants to be free" (woot flamebait!)) which have no basis in fact (see Magsol's spot-on reply in this thread).
No, it works in a evolution sense too. Machines exist in an environment which is hostile to "broken" machines. It just so happens that their survival and reproduction is mediated by an intelligent agent, but the process is the same.
Domesticated animals follow the same pattern. They're evolving within an environment whose rules of survival are set by humans. Humans didn't "intelligently design" cows, in the sense of directly choosing specific mutations to lactation hormone receptors, we just set up a selection environment in which only the cows that produce the most milk reproduce.
Darwin himself recognized the connection here. His book takes as a given that evolution (defined as gradual change in organisms) obviously exists, and asks "how?" He starts by laying out how domesticated organisms evolve via "artificial selection" by humans. Then he argues that wild organisms must operate by the same mechanism, except that reproduction depends on natural rather than manmade pressures -- therefore "natural selection".
The confusion in this thread is over the distinction between "evolution", which was patently obvious to every biologist in Darwin's time, and "evolution by natural selection", which was not.
Yes, the plants tend to be dry, oily, and highly flammable, with fire-resistant seeds. In the U.S., manzanita and similar plants are thought to do the same thing.
However, this has no bearing on whether fire is alive. Symbiosis is not a requirement of life, but (I think) evolution by natural selection is. Fire doesn't contain information about itself -- its properties are only a function of its fuel. It's not like lighting paper with a match produces a different fire than lighting it with a candle. Fire doesn't undergo natural selection, except in the trivial sense that big fires are harder to put out.
Clever, but misleading (whether or not it was intended as a joke).
Darwin's theory of natural selection requires an entity to store the information needed to make *more* of itself. You can't make more matter -- at least, not without making an equal amount of antimatter -- so no natural selection is possible.
Slashdot really needs a "+1 flamebait" moderation option.
Why *wouldn't* it be likely?
Darwin of course knew nothing of DNA, and his theory of evolution says nothing about it. Darwin didn't put it this way, but the key requirements for an entity to evolve are:
1. The entity contains the information needed to replicate (self-description)
2. This information is subject to random changes (mutation)
3. The environment is hostile -- some but *not all* entities will be destroyed (survival)
4. Variations between individuals make them more or less likely to survive (fitness)
DNA-based life fits these restrictions, but so do entities which store their self-descriptive information in RNA, protein, or computer memory. It places no restrictions whatever on the existence of life chemistry based around other atoms than carbon.
You can make lots of chemistry arguments about why carbon is necessary, but you can't argue it on pure Darwinian grounds. As for your specific point in favor of carbon:
Carbon has lots of free valences, which allow it to act like a universal lego-block
Silicon has the same valence properties, and also forms a wide variety of complex molecules. Phosphorus and sulfur can have valences of 5 or 6 in certain situations. Now, carbon *is* special, but not in the way you've described.
So what, a keychain fob is going to suddenly stop working if it gets near a Linux device? Open source is a powerful thing, but if it now has an aura that destroys all non-GPL devices in a ten foot radius, I'm really impressed.
Also, "thousands of you" means there are as many of you as there are level 80 female dwarf subtlety rogues wielding Quel'dalar. You'd be insignificant even if you *did* all quit the game rather than play on another platform... which you won't.
Copying my reply to another poster:
Direct solar thermal plants need an insane amount of plumbing and a zillion little motors to run the heliostats to point the mirrors at the sun.
This updraft machine is definitely going to have lower thermodynamic efficiency (Carnot's law guarantees it), but on the other hand it has far fewer moving parts.
Direct solar thermal plants need an insane amount of plumbing and a zillion little motors to run the heliostats to point the mirrors at the sun.
This updraft machine is definitely going to have lower thermodynamic efficiency (Carnot's law guarantees it), but on the other hand it has far fewer moving parts.
for model planes they were totally impractical just a few years ago.
Not true anymore. One of the side effects of the cell phone revolution is that their high-tech batteries and the micro-motors that make the phone vibrate allow you to build some great electric aircraft.
http://www.ezonemag.com/
For a 200-kg copter, 30-40 kW sounds about right from my calculations too. Your average top-of-the-line Li-ion battery has a specific power density of 1000 W/kg and 200 W-h/kg: 40 kg of batteries would give you enough power to lift off and 12 minutes of flight time.
Now, the only problem is fitting four electric motors with 13 horsepower each, power electronics, and a carbon composite frame into the remaining 60 kg...
Oh, and figuring out how to not die when the batteries run out.