Heh, don't feel bad, I get about 30 positive karma a week and I haven't received mod points for a couple of years now. Guess I shouldn't have criticized Dice...
If I remember correctly, moderators are picked from users with an average amount of activity. You might be falling into the obsessive side of that particular curve:)
The article is light on details, but there's details elsewhere.
The OPOC engine is a horizontally opposed two cylinder two-stroke engine. As a cylinder in a two-stroke engine has a power stroke on every revolution instead of every second revolution, this engine has very high power density compared to a four-stroke engine of the same size.
Traditionally, two-stroke engines have had very poor emissions. Since the exhaust and intake strokes are not separate, the intake mixes with the exhaust to some degree. This means that some of the intake fuel goes out the exhaust unburned, and some of the exhaust remains in the cylinder with the intake charge, reducing peak temperature. This engine, however, uses assisted HCCI with a diesel injection system, meaning the fuel is introduced during compression instead of intake, so unburned intake fuel does not cross over to the exhaust. (I'm not clear what the "assisted" part is in the assisted HCCI. Perhaps there's a spark plug that's only used during low-power, lean burn conditions?)
The cylinder pairs are intended to be balanced and stackable, so that multiples can be connected together for higher output. TFA suggests that it might even be stacked with an electric motor for low-speed operation.
I imagine these would be very useful for a hybrid, despite the summary title. Unassisted HCCI engines have a small power range, but this would be perfectly fine for a series hybrid generator motor running at a fixed RPM for charging.
Whoops, saw that you mentioned "Hide". But why would you unfriend someone for their apps if you don't see them at all?
Some people make regular posts about items they need in their favorite games in their regular status updates too, which you see even if you've hidden their apps.
You could hide their status updates or unfriend them. Since you'll no longer be seeing anything from them either way, it comes down to whether you want them to see your activity even if you no longer care for theirs.
It's good that they've released source for drivers.
It would be better still if they released documentation for their hardware that would be adequate to write a driver.
It's said that source code is the best documentation, but it only documents what the source is doing; not why it's doing it, what it could do, and what it shouldn't do.
Has anybody ever heard of [..] an EDS project that went well.
No, and that's not surprising in their field. As a company that provides infrastructure, EDS projects are expected to go well. It's not notable when they succeed.
There's just not a lot of articles in the news about "Multi-billion dollar project went as expected". It's not that they never do, rather it's not newsworthy when they do.
Meanwhile, I didn't buy a home I couldn't afford, and for some reason no one wants to just give me money.
Hah! Don't you feel foolish now.
My father once said, to paraphrase.. "you can be one of those complaining about the people getting free cash.. or you can be one of the people getting free cash."
I don't know that the typical "let's blow up a plane!" sort of terrorist we've run into of late is all that worried about getting away without trouble if they're caught. I mean, they're willing to die.
I know suicide bombing is all the rage these days, but there's plenty of would-be bombers who would prefer to live. Checking your bomb as luggage used to work (Air India Flight 182), but that doesn't fly anymore. Putting it into someone else's luggage seems like a reasonable compromise.
As for people who get in the media not needing a million bucks, A) EVERYONE needs a million bucks, even if you just turn around and give it to a charity (I'm looking at you, Sylvia "I don't need the money anyway" Brown) and B) So getting a 2 minute human interest blurb on the local news channel is an instant gateway to fame and success that makes taking a test for a million dollars a wasteful endeavor? That is such a bogus cop-out.
I'd think it would take at least a million dollars just to cope with the "fame and success" that would bring. Maybe more.
Maybe Randi could offer a reduced prize of $10,000 just to shut up on a successful claim, without the media attention.
"Cassandra did not get half the kicking around she deserved." -- Heinlein
Suppose you believed that Snow White and the Seven Dwarves are real. Is me calling you an idiot fair or bigotry?
Non-sequiter. An erronous belief does not necessarily reflect on the believer's intelligence. Calling him an idiot would just create an adversarial atmosphere, and make it less likely that he'd seriously consider your point of view.
I think that Dawkins runs into that same problem. However, he wouldn't be as popular as he is without being adversarial. Conflict sells.
Rereading it makes it very appropriate to this story though as it points out the minute variations in silicon/computers that is ignored by most software etc. as used today because of clocks etc. If the clock is not quite right, weird things can happen.
This story is more about how subtle differences in process-to-core mapping can result in real performance differences, rather than small differences in silicon. Kind of like the butterfly effect as it applies to computers.
The FPGA thing was still an interesting article, though.
One experiment went for a long time, and in the end when he analyzed the AI generated code, there were 5 paths/circuits inside that did nothing. If he disabled any or all of the 5 the overall design failed. Somehow, the AI found that creating these do nothing loops/circuits caused a favorable behavior in other parts of the FPGA that made for overall success.
The author took the unusual step of disconnecting the clock for the FPGA, taking advantaged of undefined behavior that depended on the unique electrical characteristics of the FPGA he used. Had he left the clock connected he'd likely have more portable results, however he may not have arrived at the same results since he'd be depending on discrete logic and not the unspecified, non-linear analog behavior.
I too was excited to read about vanadium redox flow batteries. For such a promising technology, it does seem to be poorly commercialized.
It seems unlikely that we'll see this in mobile applications due to the low energy density. To quote wiki:
Current production Vanadium redox batteries achieve an energy density of about 25 Wh/kg of electrolyte. More recent research at UNSW indicates that the use of precipitation inhibitors can increase the density to about 35 Wh/kg, with even higher densities made possible by controlling the electrolyte temperature. This energy density is quite low as compared to other rechargeable battery types, e.g. Lead-acid (30-40 Wh/kg) and Lithium Ion (80-200 Wh/kg).
The main advantage of vanadium redox in mobile applications is quick fills, however certain types of lithium ion batteries also allow very fast charging with much better energy density.
The flow batteries look promising for load-leveling of stationary alternative power sources. It would be interesting to see how they compare with lead-acid in $/Wh. I haven't found any figures on this.
In france, people living in bordeaux can board the train and make it to their jobs in paris, 400-500 km away, just in an hour or so.
Why are people living 400-500 km away from work?
Do they live within walking distance of the train track? Isn't the noise bothersome? If they live further, how much time to commute to the train station? How much time to walk/bus from the train station to work? Sure, traveling 300kph on your way to work is cool, but it's only part of the trip.
Regardless, if your description is accurate, it seems mass transit has enabled ridiculous commute distances rather than improving quality of life in this case.
My connection will drop every 5-10 minutes, severing my internet access. It will return by itself in 2-3 minutes or if I restart the modem.
I used to have a similar problem, except with eMule. I'd fire it up, it would run for a few minutes, then my internet connection would go down.
Turns out it was my router, a D-link DI-524. It has a tiny connection tracking table, and reboots if you go over.. which happened reguarly when using eMule's KAD network and all the UDP packets that implies. If I disabled KAD, I no longer had the problem.
You could be seeing something similar with the DHT that is used in some BitTorrent clients, or really any feature that uses UDP and hits a large number of hosts. Try disabling these features, or perhaps test with a different client entirely (with the same caveats in mind).
Could replacing the diesel engine with electric motors offset enough of the extra storage weight required by ultracapacitors?
No. The bank of ultracapacitors would be even heavier than the lithium-ion batteries discussed, and those were already very heavy, several times the weight of a diesel or gas drivetrain for equivalent range.
A diesel engine is heavier than a gasoline engine, but not that much heavier - maybe 100 kilos more at the outside on a car.
A 30A circuit at 120V (the kind an oven might plug into) provides 3600W. A typical household might have a 150-200A service.
About 1/5 of diesel's energy is realized in a typical IC engine. Using electric motors at the actuation source avoids drivetrain losses, but has little impact on weight. The weight can't really be made up - consider 50L of diesel, having an energy of 1935MJ, or 387MJ realized. With lithium-ion batteries coming in at 0.23-0.28MJ/kg, that's 1382kg of lithium-ion batteries for the same range even before considering motor and drivetrain losses. Either your electric car is going to be very heavy or have short range. (source: Energy Density)
You don't have to tank in electricity, but the copper wires to deliver it aren't free. Let's say the price you pay reflects the cost of delivering each. For kWh/$ comparison, consider the same 50L diesel tank at $1.12/L, yielding a realized 108Wh, for 1.9Wh/$. Electricity is very cheap here at 6c/kWh, for 16.7kWh/$. Not many people powering their houses on diesel.
I've used pessimistic values for diesel/IC, very optimistic values for electric, and local prices. Your mileage may vary.
Amazingly enough, there's this thing called a ground. Ever wonder why a lightning strike on a vehicle doesn't vaporize the occupants? In almost every way, an ultracapacitor is safer than a tank full of gasoline.
Vehicle occupants aren't vaporized because electricity tends to flow along the outside of conductive objects, and the occupants are inside. It may cause some heating, but the car's body has low resistance and most of the power is dissipated in the ground.
If the dielectric was pierced, one plate of the ultracapacitor would "ground" to the other plate, not the earth, releasing all the stored energy in an instant.
An ultracapacitor sufficient to power a car would have around as much energy as a lightning bolt (~500MJ). This is equivalent to about 120kg of TNT going off in your trunk.
Gasoline has an energy content of 34.6MJ/L, so a full 50L tank has 1730MJ of energy. Given Carnot efficiency, about a third of that will be realized as work, so an ultracapacitor powering a very efficient electric motor would only need ~500MJ for similar range.
Yes, gasoline has more energy by mass than TNT. It only detonates in a narrow fuel/air ratio, though, and simply burns otherwise.
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Heh, don't feel bad, I get about 30 positive karma a week and I haven't received mod points for a couple of years now. Guess I shouldn't have criticized Dice ...
If I remember correctly, moderators are picked from users with an average amount of activity. You might be falling into the obsessive side of that particular curve :)
The article is light on details, but there's details elsewhere.
The OPOC engine is a horizontally opposed two cylinder two-stroke engine. As a cylinder in a two-stroke engine has a power stroke on every revolution instead of every second revolution, this engine has very high power density compared to a four-stroke engine of the same size.
Traditionally, two-stroke engines have had very poor emissions. Since the exhaust and intake strokes are not separate, the intake mixes with the exhaust to some degree. This means that some of the intake fuel goes out the exhaust unburned, and some of the exhaust remains in the cylinder with the intake charge, reducing peak temperature. This engine, however, uses assisted HCCI with a diesel injection system, meaning the fuel is introduced during compression instead of intake, so unburned intake fuel does not cross over to the exhaust. (I'm not clear what the "assisted" part is in the assisted HCCI. Perhaps there's a spark plug that's only used during low-power, lean burn conditions?)
The cylinder pairs are intended to be balanced and stackable, so that multiples can be connected together for higher output. TFA suggests that it might even be stacked with an electric motor for low-speed operation.
I imagine these would be very useful for a hybrid, despite the summary title. Unassisted HCCI engines have a small power range, but this would be perfectly fine for a series hybrid generator motor running at a fixed RPM for charging.
Googling mortality rate by job (or similar) isn't that hard...
Wouldn't be that hard to post a link to your source either.
Conventional wisdom is often wrong; logger, fisherman, construction worker, drivers, etc. are much more dangerous.
I don't doubt that's the case, but it seems like one of those unsourced soundbites that may or may not be true. So, with all due respect..
[citation needed]
Whoops, saw that you mentioned "Hide". But why would you unfriend someone for their apps if you don't see them at all?
Some people make regular posts about items they need in their favorite games in their regular status updates too, which you see even if you've hidden their apps.
You could hide their status updates or unfriend them. Since you'll no longer be seeing anything from them either way, it comes down to whether you want them to see your activity even if you no longer care for theirs.
It's good that they've released source for drivers.
It would be better still if they released documentation for their hardware that would be adequate to write a driver.
It's said that source code is the best documentation, but it only documents what the source is doing; not why it's doing it, what it could do, and what it shouldn't do.
Has anybody ever heard of [..] an EDS project that went well.
No, and that's not surprising in their field. As a company that provides infrastructure, EDS projects are expected to go well. It's not notable when they succeed.
There's just not a lot of articles in the news about "Multi-billion dollar project went as expected". It's not that they never do, rather it's not newsworthy when they do.
Meanwhile, I didn't buy a home I couldn't afford, and for some reason no one wants to just give me money.
Hah! Don't you feel foolish now.
My father once said, to paraphrase.. "you can be one of those complaining about the people getting free cash.. or you can be one of the people getting free cash."
+1 insightful, in retrospect.
I don't know that the typical "let's blow up a plane!" sort of terrorist we've run into of late is all that worried about getting away without trouble if they're caught. I mean, they're willing to die.
I know suicide bombing is all the rage these days, but there's plenty of would-be bombers who would prefer to live. Checking your bomb as luggage used to work (Air India Flight 182), but that doesn't fly anymore. Putting it into someone else's luggage seems like a reasonable compromise.
Where is the "-1 boring" moderation?
I've been using Overrated for that. Some posts don't even merit the logged in 1, or anonymous 0.
It's a small complaint, I'm sure.. but couldn't they have given it a name that you could, you know, Google?
The business about regenerating nerves is exciting, but this also sounds useful for scar reduction/removal.
I have a couple of keloid scars that it would be nice to be rid of.
As for people who get in the media not needing a million bucks, A) EVERYONE needs a million bucks, even if you just turn around and give it to a charity (I'm looking at you, Sylvia "I don't need the money anyway" Brown) and B) So getting a 2 minute human interest blurb on the local news channel is an instant gateway to fame and success that makes taking a test for a million dollars a wasteful endeavor? That is such a bogus cop-out.
I'd think it would take at least a million dollars just to cope with the "fame and success" that would bring. Maybe more.
Maybe Randi could offer a reduced prize of $10,000 just to shut up on a successful claim, without the media attention.
"Cassandra did not get half the kicking around she deserved." -- Heinlein
Suppose you believed that Snow White and the Seven Dwarves are real. Is me calling you an idiot fair or bigotry?
Non-sequiter. An erronous belief does not necessarily reflect on the believer's intelligence. Calling him an idiot would just create an adversarial atmosphere, and make it less likely that he'd seriously consider your point of view.
I think that Dawkins runs into that same problem. However, he wouldn't be as popular as he is without being adversarial. Conflict sells.
Rereading it makes it very appropriate to this story though as it points out the minute variations in silicon/computers that is ignored by most software etc. as used today because of clocks etc. If the clock is not quite right, weird things can happen.
This story is more about how subtle differences in process-to-core mapping can result in real performance differences, rather than small differences in silicon. Kind of like the butterfly effect as it applies to computers.
The FPGA thing was still an interesting article, though.
One experiment went for a long time, and in the end when he analyzed the AI generated code, there were 5 paths/circuits inside that did nothing. If he disabled any or all of the 5 the overall design failed. Somehow, the AI found that creating these do nothing loops/circuits caused a favorable behavior in other parts of the FPGA that made for overall success.
The author took the unusual step of disconnecting the clock for the FPGA, taking advantaged of undefined behavior that depended on the unique electrical characteristics of the FPGA he used. Had he left the clock connected he'd likely have more portable results, however he may not have arrived at the same results since he'd be depending on discrete logic and not the unspecified, non-linear analog behavior.
I too was excited to read about vanadium redox flow batteries. For such a promising technology, it does seem to be poorly commercialized.
It seems unlikely that we'll see this in mobile applications due to the low energy density. To quote wiki:
Current production Vanadium redox batteries achieve an energy density of about 25 Wh/kg of electrolyte. More recent research at UNSW indicates that the use of precipitation inhibitors can increase the density to about 35 Wh/kg, with even higher densities made possible by controlling the electrolyte temperature. This energy density is quite low as compared to other rechargeable battery types, e.g. Lead-acid (30-40 Wh/kg) and Lithium Ion (80-200 Wh/kg).
The main advantage of vanadium redox in mobile applications is quick fills, however certain types of lithium ion batteries also allow very fast charging with much better energy density.
The flow batteries look promising for load-leveling of stationary alternative power sources. It would be interesting to see how they compare with lead-acid in $/Wh. I haven't found any figures on this.
Why are people living 400-500 km away from work?
Do they live within walking distance of the train track? Isn't the noise bothersome? If they live further, how much time to commute to the train station? How much time to walk/bus from the train station to work? Sure, traveling 300kph on your way to work is cool, but it's only part of the trip.
Regardless, if your description is accurate, it seems mass transit has enabled ridiculous commute distances rather than improving quality of life in this case.
I used to have a similar problem, except with eMule. I'd fire it up, it would run for a few minutes, then my internet connection would go down.
Turns out it was my router, a D-link DI-524. It has a tiny connection tracking table, and reboots if you go over.. which happened reguarly when using eMule's KAD network and all the UDP packets that implies. If I disabled KAD, I no longer had the problem.
You could be seeing something similar with the DHT that is used in some BitTorrent clients, or really any feature that uses UDP and hits a large number of hosts. Try disabling these features, or perhaps test with a different client entirely (with the same caveats in mind).
Hydrocarbons contain much more carbon by volume than CO2. Replacing the hydrocarbons with CO2 would still represent an outflux of carbon.
Yes.
3kW? Like, two hair dryer's worth?
That's hot.
No. The bank of ultracapacitors would be even heavier than the lithium-ion batteries discussed, and those were already very heavy, several times the weight of a diesel or gas drivetrain for equivalent range.
A diesel engine is heavier than a gasoline engine, but not that much heavier - maybe 100 kilos more at the outside on a car.
A 30A circuit at 120V (the kind an oven might plug into) provides 3600W. A typical household might have a 150-200A service.
About 1/5 of diesel's energy is realized in a typical IC engine. Using electric motors at the actuation source avoids drivetrain losses, but has little impact on weight. The weight can't really be made up - consider 50L of diesel, having an energy of 1935MJ, or 387MJ realized. With lithium-ion batteries coming in at 0.23-0.28MJ/kg, that's 1382kg of lithium-ion batteries for the same range even before considering motor and drivetrain losses. Either your electric car is going to be very heavy or have short range. (source: Energy Density)
You don't have to tank in electricity, but the copper wires to deliver it aren't free. Let's say the price you pay reflects the cost of delivering each. For kWh/$ comparison, consider the same 50L diesel tank at $1.12/L, yielding a realized 108Wh, for 1.9Wh/$. Electricity is very cheap here at 6c/kWh, for 16.7kWh/$. Not many people powering their houses on diesel.
I've used pessimistic values for diesel/IC, very optimistic values for electric, and local prices. Your mileage may vary.
Vehicle occupants aren't vaporized because electricity tends to flow along the outside of conductive objects, and the occupants are inside. It may cause some heating, but the car's body has low resistance and most of the power is dissipated in the ground.
If the dielectric was pierced, one plate of the ultracapacitor would "ground" to the other plate, not the earth, releasing all the stored energy in an instant.
An ultracapacitor sufficient to power a car would have around as much energy as a lightning bolt (~500MJ). This is equivalent to about 120kg of TNT going off in your trunk.