In the PDF examples, the font's line spacing is different. Are the fonts being presented notionally equal in size? It's easy to claim something is more readable even if it's only fractionally larger in line spacing or character size.
As undergraduate electrical engineers we did this in our 3rd year power lab. Use a 5-hp, 250 volt DC motor to drive a 3-phase alternator, get the speed *close* using a tachometer, then use a bank of lightbulbs connected between the alternator outputs and the power grid to determine when to connect the alternator to the grid. When the speed is close, the lights will cycle in brightness over a period of several seconds, and it's easy to connect the system at such a time as to cause minimal load shock to the alternator. Unless you misunderstand the instructions and wait until the lights are at their brightest to connect the system... the other 3rd year class did that and the whole basement stank for about a week.
With a diesel engine, the alternator acts as a speed control once the connection has been established. The throttle setting will govern which way the power flows, within a fairly broad range. However, if you go just outside that range the generator starts to slip phases with respect to the line, and that causes rapid torque fluctuations that can destroy the machine very quickly if it's not disconnected from the line.
If electricity is a commodity to be traded then the transactions should be encrypted the way bank transactions are, with all due attention paid to the security of the information and authentication of the originating system for each order. Additionally, the response of an individual generator to a given control input should still not be able to circumvent the safety system such that the power system becomes unstable to the point of overloading the generator.
And the airport security guys would figure that out on first seeing it and appreciate the symbolism, right?
She's really lucky that no one pulled the trigger. However wrong that would have been, there's something to be said for basic common sense as it pertains to achieving old age. Go to Israel sometime and do the "exit interview" at the airport, with a bunch of trinkets you picked up from the local market in your suitcase.
Having the crowd and vehicle in the background makes the hole look bigger because of perspective... given that there are no size cues in front of the hole there is no basis for saying it's 30 meters wide.
SS1 didn't do "re-entry" because it never went into orbit in the first place. SS1's maximum speed was on the order of Mach 3 (say 2000 mph), and most of that was vertical, while any sustainable low-earth orbit requires a horizontal speed on the order of 17500 mph, and that's speed you need to bleed off somehow before you can plant yourself back on earth. In space you can't just put on the brakes - your choices are to reduce your momentum by tossing stuff overboard, preferably in the direction you're going, or you have to change your momentum vector, and that also requires either impacting with something, or throwing stuff overboard. The "impacting with something" could be done using a solar sail, or I suppose you could hypothetically build an electromagnetic brake that acted against the Earth's magnetic field somehow, but either of the latter two methods require a vast active area to be able to do something within a reasonable time frame.
Re-entry using retro-rockets and aerodynamic braking (or would it be thermodynamic braking?) currently makes the most sense at least partially because your options are pretty limited by how much stuff you can carry up into orbit to begin with.
Better think way out of the box then. We have about a zillion things that are designed to be gripped and operated by a person's hand(s). Removing that interface requires that you adapt all those tools to be compatible with the next physical interface point (such as the elbow or shoulder?), as well as figuring out a logical control scheme that is as intuitive as what everyone is familiar with. Direct neural control of an angle grinder, for example, isn't very compelling to me. If you had a hand with hardwired GPS (as another example) then you'd have to map its control functions into something that the user could learn, and it would have to use the arm nerves as the interface... and they're normally only used to position the fingers and relay back touch and hot/cold/pain sensations. An interesting problem but just because you can, doesn't always mean that you should.
use a vacuum to suck it clean every once in a while.
If you do that make sure that the nozzle of the vacuum doesn't touch the XBox. In my location the air has low humidity, and all that (dry) air rushing through the hose creates enough static electricity to cause uncomfortable shocks. The few hundred volts required to cause insidious levels of static damage are imperceptible, and you can slowly kill electronics without ever realizing what you did.
d'oh... I realized that I'd misstated the time pretty quick after submitting my comment, since my 2000 Tundra has variable valve timing and it's far from the first Toyota to use the technology. Even before variable valve timing came out, Toyota and Ford (and others too, just too lazy to look up all the references) were using variable intake manifold geometry to broaden the torque curve of their engines. The most trick one I've seen was on a racing Mazda (rotary) where they used telescoping stacks to change the induction runner length as a function of throttle opening and RPM.
I must be living my life too fast... 16 years feels like 6. According to the Lorentz transformation that requires a speed of 0.8c. Who'd have thunk that?
Both Honda and Toyota have been building variable valve timing engines for the last five or six years... That part of it (at least in a basic form) is no longer a research project. Before VVT technology, you could build an engine that developed 240 BHP from 1.6 litres of displacement (such as the Formula Atlantic spec, Toyota 4AGZE based 16 valve engine), but it would have a power band that spanned maybe from 7000 to 9500 RPM. With VVT the usable power band is broadened such that there are now several production cars with engines topping 100 horsepower per litre of displacement, and they have street-friendly powerbands to boot.
But the whole point of patents is to encourage innovation, by providing protection for unique ideas. Why would anybody bother coming up with new ideas if anybody else could just copy them the next day? (That's especially true for startups, which don't have the money to compete head to head with larger, more established companies.)
The point of patents is to provide protection for unique ideas - but the intent was to provide that protection to the innovators who were trying to build a business around that unique idea. Coming up with an idea and then sitting on it while others build up the business case is trolling. Part of the "trolling" test is also, to what lengths did the inventor go to make their patent obscure to the intended field of application? I don't know if that applies in this case, but there are a lot of patents out there that are written such that only the most careful search using the most oblique terms will find them.
It says here that a 747 requires about 87000 HP to fly at cruising speed and altitude (Mach 0.9, 40,000ft). It's moving about 350 passengers. They don't provide handy numbers and I'm too lazy to look it up, but if you were to find numbers for short-haul aircraft, which would be the main competition for the TGV, you'd probably find that the ratio of power required per passenger was even higher. So, aircraft are not more fuel efficient than trains, and if you look at the safety record for high speed railways (as a function of miles covered, passengers carried, and fatalities) you'd probably find it comparable or safer than air travel. A train crash involves sliding along the ground at high speed. An aircraft crash has that, plus a high speed impact with the ground.
Ummm... your understanding is kinda flawed on a number of counts. Do a thought experiment: If you're traveling in an enclosed tunnel, even a virtual one, how much air is there in front of you that you have to push? Is it finite or does it just keep on increasing as you travel forward? How much inertia does all that air have? Now consider that behind you, there's a similar volume of air that you need to pull along. In front, where does the air that you're pushing go - and behind you, what happens to the air you're pulling along? Does it leave a vacuum behind it? Would the vacuum suck on the air that you're pulling, and thereby increase the load on the engine?
Speaking of welding there are welding shields with LCD to darken the window and I always thought that this technology if made smaller and lighter would be perfect for sunglasses.
I have one of these and it's awesome for MIG welding or any kind of electric welding where you may accidentally strike an arc from time to time, as well as the convenience aspect of not having to flip it up and down as you move from weld to weld. The interesting thing is that LCD's require an AC waveform to go dark. The little solar panel that's above the LCD screen provides this in response to the typical welding arc glare. Hold the shield up to the sun... it goes dark for a split second, then light again. Sunlight on a solar panel produces DC and won't darken the LCD.
Exactly. Naturally occurring uranium is at most 0.7% U-235, which is the fissile material used in conventional power reactors. The other 99% is discarded as "depleted" uranium and used as high density slugs in weapons. So if the world could only get over its Puritanical aversion to breeder technology, the available supply of fissile material would instantly increase by a factor of 99, not even counting the thorium that can be transmuted into U-233 (as already noted by another poster).
The difference between F1 technology and what you drive on the street is comparable to the difference between Lance Armstrong riding his bike, and you riding your bike (or atleast me riding my bike). At the consumer level, there are many options available for easy, fast, and reliable performance improvement, at relatively low cost. If you've already been to that well a few times then finding the next significant performance improvement is exponentially harder.
The efficiency gain is obrained by using the exhaust heat energy to compress the incoming air and thereby get more air into the engine, which increases power output. The increased power output requires added fuel (as well as the added air) but essentially, more of the available energy is extracted from the fuel before the exhaust is dumped overboard.
Typical gasoline engines are about 30% efficient from a heat standpoint: 30% of the chemical energy in the fuel is converted to torque at the flywheel. The remainder of the energy is more or less evenly split between the coolant and the exhaust. If the turbocharger were to extract half the available energy in the exhaust stream and use it to compress the incoming air, then that would give you a 25% increase in energy efficiency. The absolute air pressure (at sea level) is about 14 PSI. Using a turbocharger to double the intake air pressure would at least double the engine's power because it's also overcoming pumping losses in the process. Using ethanol or methanol evaporation to cool the intake charge boosts the air density while also adding to the fuel and oxygen dumped into the combustion chamber, so it's a double win. An intercooler would do the same (increasing charge density) but not add any fuel to the mix, and the heat rejected by the intercooler is dumped overboard. THe heat added to the ethanol/methanol gets recycled back out the exhaust.
Cut him some slack already...
on
DIY Laptop
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· Score: 4, Insightful
Your laptop with its "modern" $(OS) spends about 99% of its CPU cycles supporting itself. What we're seeing here could be viewed as an attempt to improve the cycles-for-the-user ratio, if nothing else. If just I want to add a couple of numbers together or edit a document, do I need, or should I have to pay for, the ability to simultaneously have an MPEG movie playing in the background?
Stripping a computer back to its bare essentials is an art. Real hot rods don't have air conditioning. Real computers don't need 3GHz CPUs, 2GB of RAM, and a 500 watt power supply to present an interactive user interface.
No way for me to know exactly what happened in that case. However, the inertial navigation system on an aircraft has to know its orientation with respect to the earth (in terms of roll/pitch/yaw) and also its position (lat/long/altitude). THere are a bunch of different ways that you can do that. One of them, for example, is the "earth centered, earth fixes" coordinate system. In this system you compute your position in a 3D orthogonal system and then do a mathematical transform to get your lat/long/altitude position. The corrections that the INS has to make for gravity are dependent on your position on the earth, and there are other corrections required due to Coriolis forces (you're curving over the surface of the earth, which gives extra centripetal acceleration, but not exactly in the same direction as gravity). When these corrections, and the data you're getting from your GPS receiver, are computed (or natively received) in different coordinate systems, then you end up making a bunch of spherical coordinate transforms, usually back and forth. These transforms are matrices of sine and cosine factors of your coordinates, and it could be that somehow they ran one of these matrices through a singularity at the date line, or else maybe it's the even/odd thing: cos of a negative angle less than 90 degrees is positive, just like cos of a positive angle less than 90. Therefore acos(cos(-60 degrees) = 60 degrees. If you didn't guard against that possibility then it could happen that the nav system got highly confused by a sudden large discrepancy between two of its subsystems' solutions, and threw in the towel.
When I worked at a high end civilian GPS equipment manufacturer, we had a test department where, among other things, a complete list of "special" dates and locations were kept on file. Any new position solution software release was regression tested against all previously known and guessed potential date/time rollovers, as well as making sure that motion across geographic coordinate boundaries didn't cause erratic behavior. Obviously whoever supplied the inertial navigation solution for the F22 hasn't quite gotten there yet... Testing in the lab is cheap. Burning a couple of tons of Jet-A and putting a bunch of people at risk is not.
Total energy cost is an interesting metric. If you look at the (total energy) cost of producing and operating an energy-efficient appliance vs. a 'dirty' appliance, the dirty appliance may actually not represent such a bad choice. The good thing about looking at things this way is that eventually people will figure out that solar PV arrays (for instance) are not helping anything if the energy and pollution required to build them exceeds their expected lifetime energy output and pollution savings. I'm not saying that is actually the case... but I also haven't looked into it in detail.
Props to the homeowner (and the NJ utilities, the municipalities and his neighbors) for putting it together though. Some folks are going to have to stick their necks out and pave the path on alternate technologies.
I didn't mean copyright, although incorporating artwork (icons, graphics, backgrounds) into a phone skin when you didn't design or acquire the rights to that artwork, would be a pretty clear case of copyright infringement. To the extent that the bloggers were providing links to the places where the skins were available, they're aiding the copyright infringement process.
I was thinking trademark infringement because I assumed that Apple would have trademarked certain aspects of the interface design. To the extent that the iPhone fits into the family of iXxx devices marketed by Apple, it might be more appropriate to class it as "trade dress" as opposed to trademark... IANAL. Apparently (according to another poster) they haven't yet filed trademark or design patent applications for the user interface of the iPhone.
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In the PDF examples, the font's line spacing is different. Are the fonts being presented notionally equal in size? It's easy to claim something is more readable even if it's only fractionally larger in line spacing or character size.
325 and beowulf was already taken?
With a diesel engine, the alternator acts as a speed control once the connection has been established. The throttle setting will govern which way the power flows, within a fairly broad range. However, if you go just outside that range the generator starts to slip phases with respect to the line, and that causes rapid torque fluctuations that can destroy the machine very quickly if it's not disconnected from the line.
If electricity is a commodity to be traded then the transactions should be encrypted the way bank transactions are, with all due attention paid to the security of the information and authentication of the originating system for each order. Additionally, the response of an individual generator to a given control input should still not be able to circumvent the safety system such that the power system becomes unstable to the point of overloading the generator.
She's really lucky that no one pulled the trigger. However wrong that would have been, there's something to be said for basic common sense as it pertains to achieving old age. Go to Israel sometime and do the "exit interview" at the airport, with a bunch of trinkets you picked up from the local market in your suitcase.
Having the crowd and vehicle in the background makes the hole look bigger because of perspective... given that there are no size cues in front of the hole there is no basis for saying it's 30 meters wide.
Heavy water, at least the deuterium-based kind, isn't radioactive.
Re-entry using retro-rockets and aerodynamic braking (or would it be thermodynamic braking?) currently makes the most sense at least partially because your options are pretty limited by how much stuff you can carry up into orbit to begin with.
Better think way out of the box then. We have about a zillion things that are designed to be gripped and operated by a person's hand(s). Removing that interface requires that you adapt all those tools to be compatible with the next physical interface point (such as the elbow or shoulder?), as well as figuring out a logical control scheme that is as intuitive as what everyone is familiar with. Direct neural control of an angle grinder, for example, isn't very compelling to me. If you had a hand with hardwired GPS (as another example) then you'd have to map its control functions into something that the user could learn, and it would have to use the arm nerves as the interface... and they're normally only used to position the fingers and relay back touch and hot/cold/pain sensations. An interesting problem but just because you can, doesn't always mean that you should.
once in a while.
If you do that make sure that the nozzle of the vacuum doesn't touch the XBox. In my location the air has low humidity, and all that (dry) air rushing through the hose creates enough static electricity to cause uncomfortable shocks. The few hundred volts required to cause insidious levels of static damage are imperceptible, and you can slowly kill electronics without ever realizing what you did.
I must be living my life too fast... 16 years feels like 6. According to the Lorentz transformation that requires a speed of 0.8c. Who'd have thunk that?
Both Honda and Toyota have been building variable valve timing engines for the last five or six years... That part of it (at least in a basic form) is no longer a research project. Before VVT technology, you could build an engine that developed 240 BHP from 1.6 litres of displacement (such as the Formula Atlantic spec, Toyota 4AGZE based 16 valve engine), but it would have a power band that spanned maybe from 7000 to 9500 RPM. With VVT the usable power band is broadened such that there are now several production cars with engines topping 100 horsepower per litre of displacement, and they have street-friendly powerbands to boot.
The point of patents is to provide protection for unique ideas - but the intent was to provide that protection to the innovators who were trying to build a business around that unique idea. Coming up with an idea and then sitting on it while others build up the business case is trolling. Part of the "trolling" test is also, to what lengths did the inventor go to make their patent obscure to the intended field of application? I don't know if that applies in this case, but there are a lot of patents out there that are written such that only the most careful search using the most oblique terms will find them.
It says here that a 747 requires about 87000 HP to fly at cruising speed and altitude (Mach 0.9, 40,000ft). It's moving about 350 passengers. They don't provide handy numbers and I'm too lazy to look it up, but if you were to find numbers for short-haul aircraft, which would be the main competition for the TGV, you'd probably find that the ratio of power required per passenger was even higher. So, aircraft are not more fuel efficient than trains, and if you look at the safety record for high speed railways (as a function of miles covered, passengers carried, and fatalities) you'd probably find it comparable or safer than air travel. A train crash involves sliding along the ground at high speed. An aircraft crash has that, plus a high speed impact with the ground.
Ummm... your understanding is kinda flawed on a number of counts. Do a thought experiment: If you're traveling in an enclosed tunnel, even a virtual one, how much air is there in front of you that you have to push? Is it finite or does it just keep on increasing as you travel forward? How much inertia does all that air have? Now consider that behind you, there's a similar volume of air that you need to pull along. In front, where does the air that you're pushing go - and behind you, what happens to the air you're pulling along? Does it leave a vacuum behind it? Would the vacuum suck on the air that you're pulling, and thereby increase the load on the engine?
I have one of these and it's awesome for MIG welding or any kind of electric welding where you may accidentally strike an arc from time to time, as well as the convenience aspect of not having to flip it up and down as you move from weld to weld. The interesting thing is that LCD's require an AC waveform to go dark. The little solar panel that's above the LCD screen provides this in response to the typical welding arc glare. Hold the shield up to the sun... it goes dark for a split second, then light again. Sunlight on a solar panel produces DC and won't darken the LCD.
Exactly. Naturally occurring uranium is at most 0.7% U-235, which is the fissile material used in conventional power reactors. The other 99% is discarded as "depleted" uranium and used as high density slugs in weapons. So if the world could only get over its Puritanical aversion to breeder technology, the available supply of fissile material would instantly increase by a factor of 99, not even counting the thorium that can be transmuted into U-233 (as already noted by another poster).
The difference between F1 technology and what you drive on the street is comparable to the difference between Lance Armstrong riding his bike, and you riding your bike (or atleast me riding my bike). At the consumer level, there are many options available for easy, fast, and reliable performance improvement, at relatively low cost. If you've already been to that well a few times then finding the next significant performance improvement is exponentially harder.
Typical gasoline engines are about 30% efficient from a heat standpoint: 30% of the chemical energy in the fuel is converted to torque at the flywheel. The remainder of the energy is more or less evenly split between the coolant and the exhaust. If the turbocharger were to extract half the available energy in the exhaust stream and use it to compress the incoming air, then that would give you a 25% increase in energy efficiency. The absolute air pressure (at sea level) is about 14 PSI. Using a turbocharger to double the intake air pressure would at least double the engine's power because it's also overcoming pumping losses in the process. Using ethanol or methanol evaporation to cool the intake charge boosts the air density while also adding to the fuel and oxygen dumped into the combustion chamber, so it's a double win. An intercooler would do the same (increasing charge density) but not add any fuel to the mix, and the heat rejected by the intercooler is dumped overboard. THe heat added to the ethanol/methanol gets recycled back out the exhaust.
Stripping a computer back to its bare essentials is an art. Real hot rods don't have air conditioning. Real computers don't need 3GHz CPUs, 2GB of RAM, and a 500 watt power supply to present an interactive user interface.
No way for me to know exactly what happened in that case. However, the inertial navigation system on an aircraft has to know its orientation with respect to the earth (in terms of roll/pitch/yaw) and also its position (lat/long/altitude). THere are a bunch of different ways that you can do that. One of them, for example, is the "earth centered, earth fixes" coordinate system. In this system you compute your position in a 3D orthogonal system and then do a mathematical transform to get your lat/long/altitude position. The corrections that the INS has to make for gravity are dependent on your position on the earth, and there are other corrections required due to Coriolis forces (you're curving over the surface of the earth, which gives extra centripetal acceleration, but not exactly in the same direction as gravity). When these corrections, and the data you're getting from your GPS receiver, are computed (or natively received) in different coordinate systems, then you end up making a bunch of spherical coordinate transforms, usually back and forth. These transforms are matrices of sine and cosine factors of your coordinates, and it could be that somehow they ran one of these matrices through a singularity at the date line, or else maybe it's the even/odd thing: cos of a negative angle less than 90 degrees is positive, just like cos of a positive angle less than 90. Therefore acos(cos(-60 degrees) = 60 degrees. If you didn't guard against that possibility then it could happen that the nav system got highly confused by a sudden large discrepancy between two of its subsystems' solutions, and threw in the towel.
When I worked at a high end civilian GPS equipment manufacturer, we had a test department where, among other things, a complete list of "special" dates and locations were kept on file. Any new position solution software release was regression tested against all previously known and guessed potential date/time rollovers, as well as making sure that motion across geographic coordinate boundaries didn't cause erratic behavior. Obviously whoever supplied the inertial navigation solution for the F22 hasn't quite gotten there yet... Testing in the lab is cheap. Burning a couple of tons of Jet-A and putting a bunch of people at risk is not.
Props to the homeowner (and the NJ utilities, the municipalities and his neighbors) for putting it together though. Some folks are going to have to stick their necks out and pave the path on alternate technologies.
Mirrordot copy of his photos
I was thinking trademark infringement because I assumed that Apple would have trademarked certain aspects of the interface design. To the extent that the iPhone fits into the family of iXxx devices marketed by Apple, it might be more appropriate to class it as "trade dress" as opposed to trademark... IANAL. Apparently (according to another poster) they haven't yet filed trademark or design patent applications for the user interface of the iPhone.