How is it far from straightforward? The goal is quite concrete. Failure is obvious. By "straightforward" I do not mean "easy", I mean easy to understand.
Far more straightforward than utopia on Earth, whatever that means.
f people spent 10% the amount of time thinking about how to improve life on Earth and they do about living on Mars we would be better off.
If your solution to a problem is "the people need to change", then it probably isn't much of a solution. A trip to Mars, on the other hand, is a straightforward engineering challenge that people have a shot at. Space nutters are not the dreamers, utopia on Earth nutters are. You CAN put people on Mars. Given high enough technology, they may even live there. And they will probably - eventually - fight with each other, because they are people.
So, how can I see the lights of the towers at Logan? Searching for those heights I've found 350 feet to be the maximum structure there.
It depends on your elevation as well, and the local curvature of the earth in your area. If you are on a "peak" and Logan is on a "peak" with a valley in between, there is no local curvature and you can see straight-line distances. Ah, why am I bothering?
Very plausible explanations, if we were stuck with only 16th century theories and equipment. Maybe you should try convincing the Amish instead of a bunch of nerds?
It depends how close you sit, and how large the TV is. The "sweet spot" right now in TVs is 65-70". At 70", a 4k screen is clearly beneficial at 5 ft away and arguably beneficial at 8 or 9ft. I don't think it is absurd to assume that the sweet spot will continue to march upwards, and with it the benefits of higher resolution.
Cable and OTA are not the only sources of content. In fact, the trend is away from those as sources. When 4k was released, people made the same complaints... now there are UHD 4k Blu-Ray disks, streaming services, and even game consoles.
I actually agree with you - in general I'd like to see US policy be to have a long-term goal of extricating ourselves from our position as World Police. With that said, existent treaties have a history and need to be honored. I think I agree that Japan is not the same place it was in the early-to-mid 20th century and can be entrusted with their own defense. However, I'd change our relationship very cautiously, and only in concert with Japan's wishes. We may no longer be in a Cold War with the USSR, which makes our current strategic situation look like a pointless mess - but China will soon be a superpower and we need to bear that in mind. Call me old-fashioned, but I don't think a oligarchy can be trusted to act in the best interests of the world without a counterbalance to their power, and the only way the US stands a long-term chance to keep up with China is in league with the other rich democracies of the world. IMHO, the EU and Japan will continue to be very important allies in the coming century.
First I thought about why I would use such an inefficient cooling solution as a heatsink and fan
Presumably, they wouldn't. Presumably they would use a liquid coolant circulated through the motor and a heat exchanger somewhere else. You still need to sink at least 20kW of power, though, so it doesn't change the size of the required heatsink - it just moves it somewhere.
Then I thought why is an electric motor putting out as much heat per watt as CPU?
It isn't. The most efficient motors are in the 99% range. It is realistic to assume a 97+% efficiency. So a 2MW motor has at least 20kW of waste energy to dissipate as heat. This is opposed to a CPU, where nearly 100% of the power is dissipated as heat. That's why the heatsink only needs to be 200x larger and not 20,000x larger.
The Toyota Prius has a 60KW electric engine as well as a traditional ICE.
The Prius does not have the same weight constraints as an airplane, nor is the motor spinning as fast. But the electric motors are cooled by the automatic transmission fluid, which has a radiator. I believe the inverter coolant also circulates through the transmission, further cooling the motors. Which reminds me - the plane will also have a 2MW inverter that will range from 95-99% efficient, requiring even more cooling... that seems pretty straightforward, though, since at least the inverter isn't moving. The batteries themselves will also require cooling.
For cooling electric motors, I'm sure you could give your mate Elon a call
Tesla patented their cooling design, so we know exactly how that works. It looks like a bullshit patent - they use the only known good way to keep fluid from leaking out of a spinning thing - centrifugal force. It is highly likely that the airplane motor will use exactly this type of cooling. But again, weight is a much bigger problem than on a car and the parts are spinning much faster. You also don't need to worry about your cooling system impeding airflow through the engine on a car.
And I'm not saying it is impossible - simply that it's a very challenging engineering problem, and it is likely to have significant trade-offs.
You are being deliberately obtuse. The US is bound by treaty to defend Japan. If you didn't know that before, you certainly do after reading my last comment. Treaties have the force of law. So any security problem for Japan is a security problem for the US, even if you neglect the thousands of US troops stationed in (drumroll) Japan.
You are probably right, but I think it would depend on the nature of the threat, the current US president, and the political mood of the time. As it is, none of that matters and it would simply be automatic - even if that meant war with China or Russia. Without the treaty, I think it would be more like the situation in Taiwan, where the involvement of the US would very much depend on other circumstances and would not be automatic.
I honestly don't follow your logic, but maybe you don't understand mine. I simply mean that the US is bound by treaty to defend Japan. Seemed like a good idea right after they killed a couple of hundred thousand Americans.
a. India is not in any kind of state of war with the US, and b. India never signed the NPT, whereas N. Korea did, and then "pulled out" after being found to be in violation.
Yes, that is the point I was trying to make. The combustion process will also expel hot matter and create an impulse as the matter is ejected, but I don't think that is a significant source of propulsion in a modern high-bypass airliner engine... most of the thrust is coming from the ducted fan. If this were a rocket, combustion would be responsible for 100% of the thrust:)
I was trying to illustrate with my thermos example of how the difficult part is not the heat sink, but getting the heat to where it can be sunk. 2MW is an enormous amount of power, and it will generate an enormous amount of heat - all localized in the middle of the busy stuff where pipes, fins, and whatnot are all in the way.
Finding the area on an airplane should not be difficult (wings, anyone?). Moving the heat from a very concentrated spot in the middle of a moving high-speed 2MW fan assembly into the heat dissipation area is the trick.
Ah, I misread your comment. I agree completely. Even if the electric system's available energy density were equivalent to that of expendable fuel, it would still be a tremendous disadvantage to lug around the entire takeoff weight of the aircraft for the duration of the journey. The aircraft would even need to be structurally beefed up to handle the extra landing weight!
A fishing boat goes out with a sizeable chunk of its net weight comprised of diesel, and returns with a sizeable chunk of its net weight comprised of fish. Not an easy challenge either - but it too will eventually happen.
Planes are in a similar situation, with their landing weight being a fraction of their takeoff weight. Battery-powered planes will need to haul around the takeoff weight the whole time, putting them at a serious disadvantage.
I think for niche applications like fishing boats and airplanes, the key to sustainability will be in cost-effectively producing a fuel from renewable resources, not from trying to pound a round peg into a square hole. When oil was over $100/barrel, there was a lot of movement in biofuels, hydrogen, ethanol, etc. I expect this will still be the way forward for applications where a consumable fuel simply makes more engineering sense.
How important is the impulse from the exhaust on modern passenger jet engines? I was under the impression that the giant fan was responsible for far more thrust. Lazy Googling seems to indicate an 80:20 bypass fan:core thrust ratio.
You still need a way to transfer the heat from where it is generated to the nice, cold heat sink. As a simple thought experiment, a motor operating in a thermos isn't really going to care much about the outside temperature - you need a way to get the heat from the motor to the air outside the thermos. Obviously you won't purposely insulate the aircraft motor, but the principle is the same.
Think about the amount of power dissipated... a 2 MW motor - even if 99% efficient - is going to dissipate 20 kW of heat. Think about the heatsink for your ~100W CPU and scale it up by 200x. Not an impossible task but definitely an engineering challenge.
All you need to know about the distaste for Hillary is that she is a multi-millionaire entirely because she sells influence. Sure, she was a talented lawyer and would be well-off one way or another... but there is something very galling about becoming dirty stinking rich simply by being well-connected. Not that there's anything particularly special about the way Donald Trump took a small fortune and slightly underperformed the S&P to make a large fortune (maybe?), but inherited wealth is something people are accustomed to. If you want someone who epitomizes "the Washington establishment", it's Hillary - and people were in an anti-establishment mood.
How does what amounts to a life sentence make sense for this crime?
Because robbery with a firearm carries a minimum mandatory sentence. He was convicted of several counts, which all add up. I have mixed feelings about this - the sentence seems excessive, but this wasn't a single lapse in judgement. He's a violent criminal, and society may very well be better off with him locked up, cost be damned. I don't know what the parole rules are for federal armed robbery, but I suspect he'll be released earlier than his life sentence would let on.
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How is it far from straightforward? The goal is quite concrete. Failure is obvious. By "straightforward" I do not mean "easy", I mean easy to understand.
Far more straightforward than utopia on Earth, whatever that means.
f people spent 10% the amount of time thinking about how to improve life on Earth and they do about living on Mars we would be better off.
If your solution to a problem is "the people need to change", then it probably isn't much of a solution. A trip to Mars, on the other hand, is a straightforward engineering challenge that people have a shot at. Space nutters are not the dreamers, utopia on Earth nutters are. You CAN put people on Mars. Given high enough technology, they may even live there. And they will probably - eventually - fight with each other, because they are people.
So, how can I see the lights of the towers at Logan? Searching for those heights I've found 350 feet to be the maximum structure there.
It depends on your elevation as well, and the local curvature of the earth in your area. If you are on a "peak" and Logan is on a "peak" with a valley in between, there is no local curvature and you can see straight-line distances. Ah, why am I bothering?
Very plausible explanations, if we were stuck with only 16th century theories and equipment. Maybe you should try convincing the Amish instead of a bunch of nerds?
It depends how close you sit, and how large the TV is. The "sweet spot" right now in TVs is 65-70". At 70", a 4k screen is clearly beneficial at 5 ft away and arguably beneficial at 8 or 9ft. I don't think it is absurd to assume that the sweet spot will continue to march upwards, and with it the benefits of higher resolution.
Cable and OTA are not the only sources of content. In fact, the trend is away from those as sources. When 4k was released, people made the same complaints... now there are UHD 4k Blu-Ray disks, streaming services, and even game consoles.
I actually agree with you - in general I'd like to see US policy be to have a long-term goal of extricating ourselves from our position as World Police. With that said, existent treaties have a history and need to be honored. I think I agree that Japan is not the same place it was in the early-to-mid 20th century and can be entrusted with their own defense. However, I'd change our relationship very cautiously, and only in concert with Japan's wishes. We may no longer be in a Cold War with the USSR, which makes our current strategic situation look like a pointless mess - but China will soon be a superpower and we need to bear that in mind. Call me old-fashioned, but I don't think a oligarchy can be trusted to act in the best interests of the world without a counterbalance to their power, and the only way the US stands a long-term chance to keep up with China is in league with the other rich democracies of the world. IMHO, the EU and Japan will continue to be very important allies in the coming century.
First I thought about why I would use such an inefficient cooling solution as a heatsink and fan
Presumably, they wouldn't. Presumably they would use a liquid coolant circulated through the motor and a heat exchanger somewhere else. You still need to sink at least 20kW of power, though, so it doesn't change the size of the required heatsink - it just moves it somewhere.
Then I thought why is an electric motor putting out as much heat per watt as CPU?
It isn't. The most efficient motors are in the 99% range. It is realistic to assume a 97+% efficiency. So a 2MW motor has at least 20kW of waste energy to dissipate as heat. This is opposed to a CPU, where nearly 100% of the power is dissipated as heat. That's why the heatsink only needs to be 200x larger and not 20,000x larger.
The Toyota Prius has a 60KW electric engine as well as a traditional ICE.
The Prius does not have the same weight constraints as an airplane, nor is the motor spinning as fast. But the electric motors are cooled by the automatic transmission fluid, which has a radiator. I believe the inverter coolant also circulates through the transmission, further cooling the motors. Which reminds me - the plane will also have a 2MW inverter that will range from 95-99% efficient, requiring even more cooling... that seems pretty straightforward, though, since at least the inverter isn't moving. The batteries themselves will also require cooling.
For cooling electric motors, I'm sure you could give your mate Elon a call
Tesla patented their cooling design, so we know exactly how that works. It looks like a bullshit patent - they use the only known good way to keep fluid from leaking out of a spinning thing - centrifugal force. It is highly likely that the airplane motor will use exactly this type of cooling. But again, weight is a much bigger problem than on a car and the parts are spinning much faster. You also don't need to worry about your cooling system impeding airflow through the engine on a car.
And I'm not saying it is impossible - simply that it's a very challenging engineering problem, and it is likely to have significant trade-offs.
What other country is bound to defend Japan by treaty?
You are being deliberately obtuse. The US is bound by treaty to defend Japan. If you didn't know that before, you certainly do after reading my last comment. Treaties have the force of law. So any security problem for Japan is a security problem for the US, even if you neglect the thousands of US troops stationed in (drumroll) Japan.
You are probably right, but I think it would depend on the nature of the threat, the current US president, and the political mood of the time. As it is, none of that matters and it would simply be automatic - even if that meant war with China or Russia. Without the treaty, I think it would be more like the situation in Taiwan, where the involvement of the US would very much depend on other circumstances and would not be automatic.
I honestly don't follow your logic, but maybe you don't understand mine. I simply mean that the US is bound by treaty to defend Japan. Seemed like a good idea right after they killed a couple of hundred thousand Americans.
It's not their "jurisdiction". It is their neighborhood. But any conflict they get into is also our conflict, due to our commitment to their security.
a. India is not in any kind of state of war with the US, and
b. India never signed the NPT, whereas N. Korea did, and then "pulled out" after being found to be in violation.
Paste the PDF into Word and save. Done.
Yes, that is the point I was trying to make. The combustion process will also expel hot matter and create an impulse as the matter is ejected, but I don't think that is a significant source of propulsion in a modern high-bypass airliner engine... most of the thrust is coming from the ducted fan. If this were a rocket, combustion would be responsible for 100% of the thrust :)
I was trying to illustrate with my thermos example of how the difficult part is not the heat sink, but getting the heat to where it can be sunk. 2MW is an enormous amount of power, and it will generate an enormous amount of heat - all localized in the middle of the busy stuff where pipes, fins, and whatnot are all in the way.
That would be awesome :)
Finding the area on an airplane should not be difficult (wings, anyone?). Moving the heat from a very concentrated spot in the middle of a moving high-speed 2MW fan assembly into the heat dissipation area is the trick.
the problem is energy/power density.
Ah, I misread your comment. I agree completely. Even if the electric system's available energy density were equivalent to that of expendable fuel, it would still be a tremendous disadvantage to lug around the entire takeoff weight of the aircraft for the duration of the journey. The aircraft would even need to be structurally beefed up to handle the extra landing weight!
A fishing boat goes out with a sizeable chunk of its net weight comprised of diesel, and returns with a sizeable chunk of its net weight comprised of fish. Not an easy challenge either - but it too will eventually happen.
Planes are in a similar situation, with their landing weight being a fraction of their takeoff weight. Battery-powered planes will need to haul around the takeoff weight the whole time, putting them at a serious disadvantage.
I think for niche applications like fishing boats and airplanes, the key to sustainability will be in cost-effectively producing a fuel from renewable resources, not from trying to pound a round peg into a square hole. When oil was over $100/barrel, there was a lot of movement in biofuels, hydrogen, ethanol, etc. I expect this will still be the way forward for applications where a consumable fuel simply makes more engineering sense.
How important is the impulse from the exhaust on modern passenger jet engines? I was under the impression that the giant fan was responsible for far more thrust. Lazy Googling seems to indicate an 80:20 bypass fan:core thrust ratio.
so it seems odd they need cooling equipment.
You still need a way to transfer the heat from where it is generated to the nice, cold heat sink. As a simple thought experiment, a motor operating in a thermos isn't really going to care much about the outside temperature - you need a way to get the heat from the motor to the air outside the thermos. Obviously you won't purposely insulate the aircraft motor, but the principle is the same.
Think about the amount of power dissipated... a 2 MW motor - even if 99% efficient - is going to dissipate 20 kW of heat. Think about the heatsink for your ~100W CPU and scale it up by 200x. Not an impossible task but definitely an engineering challenge.
All you need to know about the distaste for Hillary is that she is a multi-millionaire entirely because she sells influence. Sure, she was a talented lawyer and would be well-off one way or another... but there is something very galling about becoming dirty stinking rich simply by being well-connected. Not that there's anything particularly special about the way Donald Trump took a small fortune and slightly underperformed the S&P to make a large fortune (maybe?), but inherited wealth is something people are accustomed to. If you want someone who epitomizes "the Washington establishment", it's Hillary - and people were in an anti-establishment mood.
How does what amounts to a life sentence make sense for this crime?
Because robbery with a firearm carries a minimum mandatory sentence. He was convicted of several counts, which all add up. I have mixed feelings about this - the sentence seems excessive, but this wasn't a single lapse in judgement. He's a violent criminal, and society may very well be better off with him locked up, cost be damned. I don't know what the parole rules are for federal armed robbery, but I suspect he'll be released earlier than his life sentence would let on.