And I forgot to add it to the previous comment, but I do appreciate your help. I had always thought batteries bad because of low energy density and inefficiency, but you corrected my mistake there and have saved me from embarrasing myself again.
The only reason I foed you is because I was really ticked off at your patronizing response to my terminology mistake. I can understand you'd be sick and tired of pretend experts, but look at my side: I'm studying (just completed 3rd year EE) in a different language and whenever I discuss this topic face to face it's in said langauge, so I'm simply not used to using technical terms in English. I know it was my mistake originally to use power instead of energy, but I really did not appreciate how you responded to it.
My mistake - I meant to say energy. If I'm not talking to another electrical engineer I tend to slip into layman's terminology.
A battery with a capacity of 60KWH is not neccessarily fully charged if you run 200A @ 300V for an hour, as a significant portion of the incoming energy is dissipated as waste heat. This is where my impression of inefficient batteries came in. Maybe your car only needs 60KWH, but if half of the energy in charging is lost to heat, not even your old house could serve up the required current to charge it in an hour.
So, do you have any figures as to the charging efficiency of said batteries?
It's really easy to go off the rails if you don't check your facts.
Could you please point me to where I can find these numbers, then?
It's that I though that, although a combustion engine is far less efficient than an electrical, batteries (and especially the charge cycle) are also rather inefficient. Do you have any figures as to how much power you have to put into these batteries to charge them up to 60KWH?
Well, the thing is you simply can't upgrade it enough. A typical energy density for gasoline is 8KWH/l [1], which translates to a good 400KWH in a tank. If we assume that an electrical car is twice as efficient in terms of getting energy out of batteries (which is probably optimistic), 200KWH of batteries would be needed. I found [2] a figure of 300V for a hybrid car battery, so that gives us a recharge rate of 666AH.
To recharge your car in 1 hour, you'd have to connect it to the ditribution transformer with solid copper plates.
I just checked my box, and I don't have a breaker rated over 20A.
Your examples: 3KW @ 220V = 13.6A, still quite doable. That's high for a hairdryer, but quite possible for an electric cooking stove as you say. Thing is, most kitchens have a special breaker for the stove, oven and such and often even supply them with 380V instead of 220V. In any case, 4.8KW is still significantly bigger - 60% in fact.
Am I going to have to install a special circuit just for my laptop battery charger?
You know, I'd really like to see this fast-charging battery of Toshiba's. I simply don't see how you could charge that from a standard outlet.
Here's an estimate of the problem for a laptop battery of this type:
20,000 mAh, 20V
Assume it can be charged in 5 minutes
This means that for 5 minutes you have to maintain a current of 240 amps at 20V, a whopping 4.8KW. This is roughly equivalent to 43A at 110V or 22A at 220V.
I do not know many homes who'se circuits can handle that kind of current. Typical fuses here in Europe are 16A...
Batteries are indeed a problem, thus the emphasis on fuel cells. Of course fuel cells are expensive and hydrogen storage technology is far from ideal, but with a bit of engineering...
As for how much fossile fuels used in the production, I expect that it's significantly less even accounting for distribution inefficiencies. A power plant generating power for a city, running constantly in its optimal working point seems to me to be significantly more efficient than the average car engine. Factor green energy into that and it just keeps getting better.
I most certainly agree with you that there's more to civilization than not raping women. I do agree with the original speaker, however, that a civilization where rape is common is not really a civilization at all.
From my point of view, alienmole was pointing out three things:
The parent was apparently puritanical in his mentality towards the female gender.
It is a mark of culture that a female can act like that and survive.
Cultures that try to repress that kind of behaviour quite possibly are doing so because they fear they aren't civilized enough to handle it.
I then responded to your comment because you looked at it differently, seemingly (from my POV) thinking that he called their drunken behaviour civilized. I most certainly agree on the point that public drunkenness is very uncivilized, but I believe that alienmole's also good point was that a society in which the uncivilized behaviour of public drunkenness exists is a society that provides a safe and civilized enough environment to be publicly drunk. It definitely sounds contradictory - you have to be civilized to be uncivilized - but there's some truth to it.
But again, I strongly agree with your point (1) and I believe that western civilization still has a lot to learn in all respects, including how to handle its liquor.
The original poster talks about girls with few clothes walking the streets shouting. The first answer refers to temptation, the parent's taliban attitude towards it, and how in a civilized world you will "repress the urge to bonk her over the head and drag her back to your apartment". I see no reference to piss, puke, or any other bodily fluid. I see no reference to anti-drunk mentality being talibanish.
I do see a reference to the anti-nakedness being called talibanish. This was the first answer's point, which you completely ignored in your response to said answer, in favor of your rant against "urinating in public, vomitting on the pavement, fighting and screaming". You instead resorted to accusing him of name calling, by taking the name of caveman on yourself in order to shame him for having said it.
And by the way, I implied nothing, not being the one who answered first. I only responded to your first misguided post.
your little Half LIfe, Starcraft obsessed world. Listening to you you'd think that RTS's and FPS's are the only genre's
Never played half life, and of course there's more than RTS and FPS. You want a few more good ones? Uplink, Incredible Machines, Civilization, Neocron, Gunbound, Grim Fandango, Worms, Abe's Oddyssey... Thing is, the first three you can't play with any effectiveness on a console. Next two require net, which you don't always have next to a tv. Grim Fandango would be great on a console, but I'm not gonna get one for a single game. The console version of Worms, namely Worms 3D for the Gamecube, blows chunks. Abe's up in the air... In any case, RTS is what holds my attention the longest, and it's unworkable on a console. You can't sit close to a tv due to the resolution but you have to to get any worthwile detail (try shogun sometime). And how do you work a mouse without a desk? A mouse, not a trackball...
Come back when you can form a coherent argument with examples. Till then, get lost punk.
...and the next morning read in the paper that rape has gone up yet again
The rape figure is indicative of how "civilized" your country is, in addition to how well it can deal with deviants. I expect that for the same behaviour it would be a lot higher in past times...
As for the unappetizing sight of drunks, I believe that's beside the point. The issue was not that people are allowed to get smashed but that they feel safe enough to return home in that very vulnerable state. They know that society will protect them from thieves, rapists and a whole mess of other nasty creatures, and thus feel free to walk home in such states. Again, try and walk home alone, drunk, and at night a few hundred years ago and you'd be lucky to still have the clothes on your back the next morning (or even wake up at all).
Consoles are fine for FPS, RPGs etc, where you take on a persona and everything happens in close to the first person. However, the interface is simply not designed for complex strategy and simulation games. Can you imagine trying to control and coordinate groups of troops in Starcraft or Shogun using that little game controller? How about things like Railroad Tycoon - you'd need a virtual pointer written into the game to be able to perform all the different possible actions.
Nothing beats a mouse and keyboard in terms of flexibility and control. A pointer is analagous to a hand, allowing you to select, grab etc... far more effectively than a joystick or dpad would. And in terms of quick response, nothing beats key shortcuts. Try to coordinate an attack with a hundred hydralisks with that playstation controller - by the time you've given the last group their orders the fight will be long past.
You can have my gaming computer when you pry it from my cold dead fingers.
Thing is, most ISPs would be thrilled with an excuse to block all ports and DENY requests to open them on a per-individual basis. This is namely due to their hatred of private servers, which devour all upstream bandwidth. In addition to that, the firewall rules needed to block ports on a user-basis would probably be a significant burden on their systems.
All inbound ports 1024 are blocked on my net connetion, but I don't dare ask for an exception because they'll hit me with the no-servers clause in their terms of service...
There's nothing revolutionary about a motor with no permanent magnets. PM-less DC motors have existed for decades, using electromagnets in the place. Reluctance motors (?) are similar: they have a multipronged rotor, slightly offset from the magnetic poles, that delivers force by pulsing the electromagnets in series.
More recently (still at least a decade) AC motors have been growing in popularity, and they work on the principle of magnetic induction. Of course, it's difficult to start one if the rotor is completely demagnitized as it prefers that there's at least a tiny bit of a field, but nontheless...
Your physics results agrees with my theory - either homework or studying. Except for Latin, I never studied or reviewed... How about the teacher? Was he/she any good? If you find someone who can teach a good class, it might be easier to get by with little work.
You could also just be an exception - I'm willing to admit my theory isn't applicable to everyone. If you can get by with solely class-time, I admire your retention.
Studying engineering, specifically EE. Will probably opt to specialize in Telecom.
sometimes, you can be thrown out if you say something not correct after 5'
I can only imagine how bad that would be, but sometimes that's a blessing. My first verbal calc exam my professor did everything but laugh at me when he looked over my answers. I hadn't studied enough and couldn't answer the questions properly and he took the chance to rub my nose in it. I failed the class and only passed on to the next year because my other grades were pretty decent (you don't have to pass everything here to advance, and if you advance you don't repeat any courses).
Of course, he was an exception. Most of the professors try to help you a bit if you're struggling. If you know your stuff and can demonstrate it, there's a good chance you'll pass.
those 6 weeks (2 times) are the only period when you really need to work, so just relax during the year and enjoy student's live
You better believe I do:) My view's skewed as I'm in the middle of those 6 weeks right now, but I personally think it's mentally unhealthy - you become far too stressed out. You're also only learning for the short term and if you happen to get a bad exam... Last year that happened: 'Strength of Materials', two questions, and one of them required at least two hours of pencil and paper calculations just to work out the numerical result. I made a mistake early on and it all went to hell (BTW, 2 out of the 20 who had that exam passed, with 50%). Same year, opposite situation with calculus. One of the two exam questions was analysis of an electrical circuit with a few condensers & spools. The professor had said he might do that, everyone had forgotten, and the only reason I managed it was because it's my hobby too. I failed the exam, though (didn't know my theoretical proofs well enough - same calc prof as the first time).
This system makes for a great year, but a painful exam period. If you actually had to pass all your courses to continue on (and passing here is 50%), it would be unworkable. I actually *expect* to fail at least one of the six exams I'm gonna be taking in the next few weeks... (probably business - has a reputation for asking troublesome detail questions)
In retrospect I'm probably being too negative about it - chalk it down to stress:)
I agree - for below-college it should definitely be the effort that counts. Of course then you have to make the homework something where you can evaluate effort rather than checking off the answer (something they should do anyway, I think).
In college, it doesn't have to be homework in the 'nightly problems' sense but I do believe that there should be some form of evaluation besides end-of-semester exams. I've managed to survive the system here, despite being lazy and not knowing how to study effectively, but I don't think it's the most effective way to learn this stuff. With a single exam system the tendency is to waste most of the year and then try to jam everything in there at the end - stressful, and in my opinion mentally unhealthy. I've talked to people in their late 40s who still have nightmares about exams.
Of course, the best answer to my situation would be 'do work on your own initiative!' True, but to do that here (Belgium, if anyone's familiar with the system) you have to be especially self-motivated. There is not only a lack of intitutional motivation, but of social motivation - grades are simply not important (as long as you pass, which is hard enough) and not many people work during the year. When you get back from class it's too tiring to open the textbook, and everyone goes home for the weekends, where you're definitely not gonna work.
I'm lazy by my own admission, but it's made worse by the total lack of attempt to instil a work ethic. If I'm supposed to get that out of high school, then HS failed miserably, probably for the same reasons as with you - I didn't have to work much to do well.
Think about it - as soon as it becomes known that there is decent PIM software for the PSP, it becomes an acceptable tool in the business world. Install those emulators and a few games and you'll never have a boring meeting again, and the great thing is that no one will notice!
They'll all think you're rearranging your calendar or taking notes while you merrily bounce your way from koopa to koopa.
Slashdot Mirror
I'd actually want to see someone try it.. :-)
t ml
Here you go:
http://www.checkerboardnightmare.com/d/20010103.h
Jw
Apparently he ran into a virtual Grendel...
And I forgot to add it to the previous comment, but I do appreciate your help. I had always thought batteries bad because of low energy density and inefficiency, but you corrected my mistake there and have saved me from embarrasing myself again.
The only reason I foed you is because I was really ticked off at your patronizing response to my terminology mistake. I can understand you'd be sick and tired of pretend experts, but look at my side: I'm studying (just completed 3rd year EE) in a different language and whenever I discuss this topic face to face it's in said langauge, so I'm simply not used to using technical terms in English. I know it was my mistake originally to use power instead of energy, but I really did not appreciate how you responded to it.
Jw
I foed you when you ridiculed me - I simply hadn't gotten around to changing it and I sincerely apologise for that.
Jw
What if we register an account at said spam servers and start spamming the higherups of the communist party? Think we can get some action out of them?
Send 'em ads for things like "Insurrection for Dummies" and "The Subversionist's Handbook"
Jw
My mistake - I meant to say energy. If I'm not talking to another electrical engineer I tend to slip into layman's terminology.
A battery with a capacity of 60KWH is not neccessarily fully charged if you run 200A @ 300V for an hour, as a significant portion of the incoming energy is dissipated as waste heat.
This is where my impression of inefficient batteries came in. Maybe your car only needs 60KWH, but if half of the energy in charging is lost to heat, not even your old house could serve up the required current to charge it in an hour.
So, do you have any figures as to the charging efficiency of said batteries?
Jw
It's really easy to go off the rails if you don't check your facts.
Could you please point me to where I can find these numbers, then?
It's that I though that, although a combustion engine is far less efficient than an electrical, batteries (and especially the charge cycle) are also rather inefficient. Do you have any figures as to how much power you have to put into these batteries to charge them up to 60KWH?
Jw
Well, the thing is you simply can't upgrade it enough. A typical energy density for gasoline is 8KWH/l [1], which translates to a good 400KWH in a tank. If we assume that an electrical car is twice as efficient in terms of getting energy out of batteries (which is probably optimistic), 200KWH of batteries would be needed. I found [2] a figure of 300V for a hybrid car battery, so that gives us a recharge rate of 666AH.
s html
To recharge your car in 1 hour, you'd have to connect it to the ditribution transformer with solid copper plates.
Jw
[1] http://hypertextbook.com/facts/2003/ArthurGolnik.
[2] http://www.hybridcars.com/battery-comparison.html
I just checked my box, and I don't have a breaker rated over 20A.
Your examples: 3KW @ 220V = 13.6A, still quite doable. That's high for a hairdryer, but quite possible for an electric cooking stove as you say. Thing is, most kitchens have a special breaker for the stove, oven and such and often even supply them with 380V instead of 220V. In any case, 4.8KW is still significantly bigger - 60% in fact.
Am I going to have to install a special circuit just for my laptop battery charger?
Jw
Here's an estimate of the problem for a laptop battery of this type:
- 20,000 mAh, 20V
- Assume it can be charged in 5 minutes
This means that for 5 minutes you have to maintain a current of 240 amps at 20V, a whopping 4.8KW. This is roughly equivalent to 43A at 110V or 22A at 220V.I do not know many homes who'se circuits can handle that kind of current. Typical fuses here in Europe are 16A...
Jw
Batteries are indeed a problem, thus the emphasis on fuel cells. Of course fuel cells are expensive and hydrogen storage technology is far from ideal, but with a bit of engineering...
As for how much fossile fuels used in the production, I expect that it's significantly less even accounting for distribution inefficiencies. A power plant generating power for a city, running constantly in its optimal working point seems to me to be significantly more efficient than the average car engine. Factor green energy into that and it just keeps getting better.
Jw
As for how we interpreted the comments differently, I'll try to explain my side so that we can put this misunderstanding behind us.
The first comment I saw was this response (pls excuse my bad linking):
http://slashdot.org/comments.pl?sid=151538&thresh
From my point of view, alienmole was pointing out three things:
- The parent was apparently puritanical in his mentality towards the female gender.
- It is a mark of culture that a female can act like that and survive.
- Cultures that try to repress that kind of behaviour quite possibly are doing so because they fear they aren't civilized enough to handle it.
I then responded to your comment because you looked at it differently, seemingly (from my POV) thinking that he called their drunken behaviour civilized. I most certainly agree on the point that public drunkenness is very uncivilized, but I believe that alienmole's also good point was that a society in which the uncivilized behaviour of public drunkenness exists is a society that provides a safe and civilized enough environment to be publicly drunk. It definitely sounds contradictory - you have to be civilized to be uncivilized - but there's some truth to it.But again, I strongly agree with your point (1) and I believe that western civilization still has a lot to learn in all respects, including how to handle its liquor.
Jw
One of the joys of watching TV is melting into the couch to watch. An office chair doesn't give quite the same effect.
Jw
The original poster talks about girls with few clothes walking the streets shouting. The first answer refers to temptation, the parent's taliban attitude towards it, and how in a civilized world you will "repress the urge to bonk her over the head and drag her back to your apartment". I see no reference to piss, puke, or any other bodily fluid. I see no reference to anti-drunk mentality being talibanish.
I do see a reference to the anti-nakedness being called talibanish. This was the first answer's point, which you completely ignored in your response to said answer, in favor of your rant against "urinating in public, vomitting on the pavement, fighting and screaming". You instead resorted to accusing him of name calling, by taking the name of caveman on yourself in order to shame him for having said it.
And by the way, I implied nothing, not being the one who answered first. I only responded to your first misguided post.
Jw
your little Half LIfe, Starcraft obsessed world. Listening to you you'd think that RTS's and FPS's are the only genre's
Never played half life, and of course there's more than RTS and FPS. You want a few more good ones? Uplink, Incredible Machines, Civilization, Neocron, Gunbound, Grim Fandango, Worms, Abe's Oddyssey...
Thing is, the first three you can't play with any effectiveness on a console. Next two require net, which you don't always have next to a tv. Grim Fandango would be great on a console, but I'm not gonna get one for a single game. The console version of Worms, namely Worms 3D for the Gamecube, blows chunks. Abe's up in the air...
In any case, RTS is what holds my attention the longest, and it's unworkable on a console. You can't sit close to a tv due to the resolution but you have to to get any worthwile detail (try shogun sometime). And how do you work a mouse without a desk? A mouse, not a trackball...
Come back when you can form a coherent argument with examples. Till then, get lost punk.
Jw
...and the next morning read in the paper that rape has gone up yet again
The rape figure is indicative of how "civilized" your country is, in addition to how well it can deal with deviants. I expect that for the same behaviour it would be a lot higher in past times...
As for the unappetizing sight of drunks, I believe that's beside the point. The issue was not that people are allowed to get smashed but that they feel safe enough to return home in that very vulnerable state. They know that society will protect them from thieves, rapists and a whole mess of other nasty creatures, and thus feel free to walk home in such states. Again, try and walk home alone, drunk, and at night a few hundred years ago and you'd be lucky to still have the clothes on your back the next morning (or even wake up at all).
Jw
Consoles are fine for FPS, RPGs etc, where you take on a persona and everything happens in close to the first person. However, the interface is simply not designed for complex strategy and simulation games. Can you imagine trying to control and coordinate groups of troops in Starcraft or Shogun using that little game controller? How about things like Railroad Tycoon - you'd need a virtual pointer written into the game to be able to perform all the different possible actions.
Nothing beats a mouse and keyboard in terms of flexibility and control. A pointer is analagous to a hand, allowing you to select, grab etc... far more effectively than a joystick or dpad would. And in terms of quick response, nothing beats key shortcuts. Try to coordinate an attack with a hundred hydralisks with that playstation controller - by the time you've given the last group their orders the fight will be long past.
You can have my gaming computer when you pry it from my cold dead fingers.
Jw
Thing is, most ISPs would be thrilled with an excuse to block all ports and DENY requests to open them on a per-individual basis. This is namely due to their hatred of private servers, which devour all upstream bandwidth. In addition to that, the firewall rules needed to block ports on a user-basis would probably be a significant burden on their systems.
All inbound ports 1024 are blocked on my net connetion, but I don't dare ask for an exception because they'll hit me with the no-servers clause in their terms of service...
Jw
There's nothing revolutionary about a motor with no permanent magnets. PM-less DC motors have existed for decades, using electromagnets in the place. Reluctance motors (?) are similar: they have a multipronged rotor, slightly offset from the magnetic poles, that delivers force by pulsing the electromagnets in series.
More recently (still at least a decade) AC motors have been growing in popularity, and they work on the principle of magnetic induction. Of course, it's difficult to start one if the rotor is completely demagnitized as it prefers that there's at least a tiny bit of a field, but nontheless...
Jw
Did you study or review at all in chemistry?
Your physics results agrees with my theory - either homework or studying. Except for Latin, I never studied or reviewed...
How about the teacher? Was he/she any good? If you find someone who can teach a good class, it might be easier to get by with little work.
You could also just be an exception - I'm willing to admit my theory isn't applicable to everyone. If you can get by with solely class-time, I admire your retention.
Jw
Watch out - I know someone who does this. On a good night he can set off car alarms...
Jw
It doesn't actually have to be usable, it just has to be plausible.
As for no koopas, you missed the point the article, namely the part about the snes and gameboy emulators for the psp...
Jw
Studying engineering, specifically EE. Will probably opt to specialize in Telecom.
:)
:)
sometimes, you can be thrown out if you say something not correct after 5'
I can only imagine how bad that would be, but sometimes that's a blessing. My first verbal calc exam my professor did everything but laugh at me when he looked over my answers. I hadn't studied enough and couldn't answer the questions properly and he took the chance to rub my nose in it. I failed the class and only passed on to the next year because my other grades were pretty decent (you don't have to pass everything here to advance, and if you advance you don't repeat any courses).
Of course, he was an exception. Most of the professors try to help you a bit if you're struggling. If you know your stuff and can demonstrate it, there's a good chance you'll pass.
those 6 weeks (2 times) are the only period when you really need to work, so just relax during the year and enjoy student's live
You better believe I do
My view's skewed as I'm in the middle of those 6 weeks right now, but I personally think it's mentally unhealthy - you become far too stressed out. You're also only learning for the short term and if you happen to get a bad exam...
Last year that happened: 'Strength of Materials', two questions, and one of them required at least two hours of pencil and paper calculations just to work out the numerical result. I made a mistake early on and it all went to hell (BTW, 2 out of the 20 who had that exam passed, with 50%).
Same year, opposite situation with calculus. One of the two exam questions was analysis of an electrical circuit with a few condensers & spools. The professor had said he might do that, everyone had forgotten, and the only reason I managed it was because it's my hobby too. I failed the exam, though (didn't know my theoretical proofs well enough - same calc prof as the first time).
This system makes for a great year, but a painful exam period. If you actually had to pass all your courses to continue on (and passing here is 50%), it would be unworkable. I actually *expect* to fail at least one of the six exams I'm gonna be taking in the next few weeks... (probably business - has a reputation for asking troublesome detail questions)
In retrospect I'm probably being too negative about it - chalk it down to stress
Jw
I agree - for below-college it should definitely be the effort that counts. Of course then you have to make the homework something where you can evaluate effort rather than checking off the answer (something they should do anyway, I think).
In college, it doesn't have to be homework in the 'nightly problems' sense but I do believe that there should be some form of evaluation besides end-of-semester exams. I've managed to survive the system here, despite being lazy and not knowing how to study effectively, but I don't think it's the most effective way to learn this stuff. With a single exam system the tendency is to waste most of the year and then try to jam everything in there at the end - stressful, and in my opinion mentally unhealthy. I've talked to people in their late 40s who still have nightmares about exams.
Of course, the best answer to my situation would be 'do work on your own initiative!' True, but to do that here (Belgium, if anyone's familiar with the system) you have to be especially self-motivated. There is not only a lack of intitutional motivation, but of social motivation - grades are simply not important (as long as you pass, which is hard enough) and not many people work during the year. When you get back from class it's too tiring to open the textbook, and everyone goes home for the weekends, where you're definitely not gonna work.
I'm lazy by my own admission, but it's made worse by the total lack of attempt to instil a work ethic. If I'm supposed to get that out of high school, then HS failed miserably, probably for the same reasons as with you - I didn't have to work much to do well.
Jw
You kidding me? The PSP would be a wonderful PDA!
;)
Think about it - as soon as it becomes known that there is decent PIM software for the PSP, it becomes an acceptable tool in the business world. Install those emulators and a few games and you'll never have a boring meeting again, and the great thing is that no one will notice!
They'll all think you're rearranging your calendar or taking notes while you merrily bounce your way from koopa to koopa.
Jw