Not even a wristwatch? Some run 10 years on a button battery.
The article notes that this technology out performs human mounted solar cells. Seeing as there are currently solar powered wrist watches, I believe this new device is capable of powering a wristwatch, but that's about it.
Unfortunately, the summary and the Physics Buzz article grossly misrepresent the research being done here. The device only becomes "uncomfortably cold" when ambient temperatures are below what are considered comfortable by most people. The AIP article also notes that it is unlikely that this device will ever be able to harvest enough energy to power current portable devices. They instead suggest that future devices be designed around the power output of this device.
TFA states that the headband only becomes uncomfortable below 19 degrees Celsius, which is below common room temperatures. One could argue that a human would be uncomfortable below room temperature wheather they are wearing this device or not.
However, you are correct. Humans are not good at judging temperature. We are good at judging heat transfer, which is why metal objects seem colder at the same temperature as nonmetals.
It feels cold because it's sucking heat out and using it. So it's constantly leaching heat out. Hence it would feel cold. Simple, really.
From TFA:
at lower ambient temperatures, the heat flow rapidly exceeds the sensation of discomfort and the device turns into uncomfortably cold object. For example, at 19C, the TEG already produces 3.7 mW, but the sensation of cold becomes too annoying.
At 19C you would start to become uncomfortable whether you were wearing this device or not.
Wouldn't it be extremely marketable? Especially for the military with troops in hot places and with bulky body armor and probably all types of personal electronic equipment to keep charged?
This also defies the laws of thermodynamics. Allow me to explain:
1. In Iraq, the surroundings are hotter than the human body. Therefore, it is impossible to harvest energy from human waste heat because heat is flowing to the human, not away from it.
2. The temperature gradient between a humans body and it's surroundings is not large enough to generate significant amounts of electricity. If it was, internal combustion engines would be a hell of a lot more efficient than they are today.
3. If the temperature gradient between a human body and it's surroundings were large enough to generate significant amounts of electricity, you might want that energy to keep warm!
When it comes time to rebuild the engine the big block can be rebuilt several times over for what the Diesel will Cost.
I feel the need to stress the fact that there are rebuildable engines and non-rebuildable engines.
Semi engines are rebuildable. They have replacable cylinder liners and bearings that can be removed and replaced. Yes, this is expensive, but it's cheaper than a new engine. These are the engines that run for a million miles +.
Most diesel pickup truck engines are non-rebuildable. Their bearings are replaceable, but the cylinder bore is actually part of the cast block. You can hone the bore, replace the bearings, and put in thicker rings, but you can usually only do this once.
Big block gasoline engines, are also non-rebuildable. That is why you've never seen one run for a million miles. I'm sure it is possible to make one that is rebuildable, but there just isn't a market for them. People who put that many miles on an engine usually prefer the superior fuel economy of a diesel.
This is a big sign of the end of the era of user-maintainable cars.
Not true. Ever look under the hood of a Honda? Why do you think all of the teenage kids buy them and put exhaust systems on them? They're dead simple to work on.
Plenty of other big blocks being made, no real reason to want a 50 year old design of a cast iron lump. Lots of new ones being built and machined, mostly aluminum.
From what I understood of the fine article, it was the last big block V-8 manufactured at that particular plant! This doesn't mean there will be no more big blocks. Just no more made at the Tonawanda engine plant.
Screw V-6's. Inline 6's have more power and better reliability. Inline engines always do.
I wouldn't say that's always the case. Inline 6's are inherently balanced, which tends to make them better. Unfortunately, their configuration makes them awkward to fit into most vehicles.
Just because a particular engine is an I-6 doesn't necessarily mean it's better. The designers of said engine could be clinically insane, and the build quality could be terrible. In which case, a well thought out V-6 would be better.
if the fact that Chrome OS is open source and you can download the source code and look for yourself doesn't convince you.
While I haven't dug through the source code myself, the builds I have seen run X11. Anyone can check. Just run Chrome which ever way you feel convenient, and type "file:///" in the address bar. Click on etc and then X11. There it is.
Yes, for all intents and purposes, Chrome OS is just a stripped down version of Ubuntu. For all of you wondering why Chrome runs so well on X11. Now you know why.
Yes, I'm guessing it uses a knock sensor as well. Current use of knock sensors can vary valve timing to change the effective compression ratio from ~11:1 to about 9:1. However, I'm not sure a knock sensor strategy is the most durable choice for such extreme changes in compression as demonstrated here.
I'm speculating that if Lotus has used the knock sensor to control compression ratio, the engine won't run very well for a few miles after each fill up. This would be because the ECU would essentially have to remap everything for the new fuel.
There are lots of Flex-Fuel cars on the road these days. The big difference here is that it runs efficiently on multiple fuels.
Current flex fuel vehicles run on a standard ~9:1 compression ratio. This ratio burns regular 87 octane pump gas just fine. But E85 has an octane rating of approximately 105. This means it can run at much higher compression ratios (like 14:1). Higher compression ratios mean higher efficiency.
Because current Flex-Fuel vehicles burn E85 at 9:1 compression ratios, they experience a 30% reduction in efficiency on E85. This engine won't experience that. Not only can it run on multiple types of fuel, it can do so efficiently.
I'm interested in what kind of control logic they use to vary the compression ratio. How do they know the combustion properties of the fuel?
Disclaimer: I am a combustion engineer, and I have spent the past 3 years working on 2-stroke diesel engines.
Slashdot Mirror
what about those of us that have an irrational fear of glitter?
The glitter... It's everywhere! IT"S IN MY EYES!
So the laws of thermodynamics still apply, even in Belgium?
Yes, even in Belgium!
Not even a wristwatch? Some run 10 years on a button battery.
The article notes that this technology out performs human mounted solar cells. Seeing as there are currently solar powered wrist watches, I believe this new device is capable of powering a wristwatch, but that's about it.
Unfortunately, the summary and the Physics Buzz article grossly misrepresent the research being done here. The device only becomes "uncomfortably cold" when ambient temperatures are below what are considered comfortable by most people. The AIP article also notes that it is unlikely that this device will ever be able to harvest enough energy to power current portable devices. They instead suggest that future devices be designed around the power output of this device.
TFA states that the headband only becomes uncomfortable below 19 degrees Celsius, which is below common room temperatures. One could argue that a human would be uncomfortable below room temperature wheather they are wearing this device or not.
However, you are correct. Humans are not good at judging temperature. We are good at judging heat transfer, which is why metal objects seem colder at the same temperature as nonmetals.
It feels cold because it's sucking heat out and using it. So it's constantly leaching heat out. Hence it would feel cold. Simple, really.
From TFA:
At 19C you would start to become uncomfortable whether you were wearing this device or not.
Wouldn't it be extremely marketable? Especially for the military with troops in hot places and with bulky body armor and probably all types of personal electronic equipment to keep charged?
This also defies the laws of thermodynamics. Allow me to explain:
1. In Iraq, the surroundings are hotter than the human body. Therefore, it is impossible to harvest energy from human waste heat because heat is flowing to the human, not away from it.
2. The temperature gradient between a humans body and it's surroundings is not large enough to generate significant amounts of electricity. If it was, internal combustion engines would be a hell of a lot more efficient than they are today.
3. If the temperature gradient between a human body and it's surroundings were large enough to generate significant amounts of electricity, you might want that energy to keep warm!
Because they are morons?
Precisely my point. It's so easy, a moron can do it!
When it comes time to rebuild the engine the big block can be rebuilt several times over for what the Diesel will Cost.
I feel the need to stress the fact that there are rebuildable engines and non-rebuildable engines.
Semi engines are rebuildable. They have replacable cylinder liners and bearings that can be removed and replaced. Yes, this is expensive, but it's cheaper than a new engine. These are the engines that run for a million miles +.
Most diesel pickup truck engines are non-rebuildable. Their bearings are replaceable, but the cylinder bore is actually part of the cast block. You can hone the bore, replace the bearings, and put in thicker rings, but you can usually only do this once.
Big block gasoline engines, are also non-rebuildable. That is why you've never seen one run for a million miles. I'm sure it is possible to make one that is rebuildable, but there just isn't a market for them. People who put that many miles on an engine usually prefer the superior fuel economy of a diesel.
This is a big sign of the end of the era of user-maintainable cars.
Not true. Ever look under the hood of a Honda? Why do you think all of the teenage kids buy them and put exhaust systems on them? They're dead simple to work on.
Plenty of other big blocks being made, no real reason to want a 50 year old design of a cast iron lump. Lots of new ones being built and machined, mostly aluminum.
From what I understood of the fine article, it was the last big block V-8 manufactured at that particular plant! This doesn't mean there will be no more big blocks. Just no more made at the Tonawanda engine plant.
Screw V-6's. Inline 6's have more power and better reliability. Inline engines always do.
I wouldn't say that's always the case. Inline 6's are inherently balanced, which tends to make them better. Unfortunately, their configuration makes them awkward to fit into most vehicles.
Just because a particular engine is an I-6 doesn't necessarily mean it's better. The designers of said engine could be clinically insane, and the build quality could be terrible. In which case, a well thought out V-6 would be better.
that the Chinese put a railway right through the middle of Tibet either.
Discovery Health should totally do a story on this one.
because I heard the fad was started by hotel chains to increase business. Source
You can't fix stupid.
-Ron White
Yes, that post really implies that Google has access to one of these quantum chips, and has tested it. If this is true, this is HUGE news.
if the fact that Chrome OS is open source and you can download the source code and look for yourself doesn't convince you.
While I haven't dug through the source code myself, the builds I have seen run X11. Anyone can check. Just run Chrome which ever way you feel convenient, and type "file:///" in the address bar. Click on etc and then X11. There it is.
It just runs faster -- and the fact that it does so without really trying is what had everyone puzzled.
How do you know they didn't try? We don't know one way or the other.
I think that's only meant to be true of the development builds. You shouldn't expect Chrome OS devices to be running X11 on actual hardware.
I beg to differ. I think Google optimized Chrome for X11 because they were planning on using it for Chrome OS.
Here's another.
Doesn't change the fact that it is a non-standard distro that doesn't even have X11.
It does have X11. It's just that the only interface is the Chrome browser.
Yes, for all intents and purposes, Chrome OS is just a stripped down version of Ubuntu. For all of you wondering why Chrome runs so well on X11. Now you know why.
Yes, I'm guessing it uses a knock sensor as well. Current use of knock sensors can vary valve timing to change the effective compression ratio from ~11:1 to about 9:1. However, I'm not sure a knock sensor strategy is the most durable choice for such extreme changes in compression as demonstrated here.
I'm speculating that if Lotus has used the knock sensor to control compression ratio, the engine won't run very well for a few miles after each fill up. This would be because the ECU would essentially have to remap everything for the new fuel.
You've missed the Flex-Fuel
There are lots of Flex-Fuel cars on the road these days. The big difference here is that it runs efficiently on multiple fuels.
Current flex fuel vehicles run on a standard ~9:1 compression ratio. This ratio burns regular 87 octane pump gas just fine. But E85 has an octane rating of approximately 105. This means it can run at much higher compression ratios (like 14:1). Higher compression ratios mean higher efficiency.
Because current Flex-Fuel vehicles burn E85 at 9:1 compression ratios, they experience a 30% reduction in efficiency on E85. This engine won't experience that. Not only can it run on multiple types of fuel, it can do so efficiently.
I'm interested in what kind of control logic they use to vary the compression ratio. How do they know the combustion properties of the fuel?
Disclaimer: I am a combustion engineer, and I have spent the past 3 years working on 2-stroke diesel engines.