So what is the efficiency of typical direct-electric chargers
This varies wildly. It's possible to make it about 90% efficient if you spend $10 in parts, but most manufacturers want to put out something cheaper than that. Many wall warts are less than 50% efficient (you can check by reading the input and output ratings on the label).
including while they're usually not charging a battery (but might or might not still be connected)?
Same as the MPG of an idling car. Zero divided by any number is still zero. What you want to know is the no-load power. Get a Kill-A-Watt, buy one of these things, post your review on the web somewhere, or find someone to do it for you.
Alternatively, just put your hand on it and see if it feels warm.
Let's say these chargers consume 100W. 25% efficiency puts 25j of heat into the air every second.
I'll assume you meant 75% efficiency - we usually measure efficiency by how much energy is not wasted as heat.
The air conditioner at 20% efficiency requires 125W to cool 25j of heat each second.
I don't know where you got this from. There is no such thing as a 20% efficient air conditioner on the market. Most are around 50% thermodynamically efficent which does not mean they use 2 watts to move a watt out of a room (look up Carnot cycle). An old clunky 10 SEER air conditioner uses 1 watt of electricity to move 2.92 watts out of a room. A modern 15 SEER AC unit uses 1 watt to move 4.39 watts out of a room.
The air conditioner in your example needs 6 to 9 watts to cool 25 watts - not 125.
surely you would rather the computer be in an endless reboot cycle (remove the loading screen too) rather than have a projected blue screen for everyone to see you are having problems.
I would rather the computer have two screens with the second one reserved entirely for presentation - BIOS POST, bootup, desktop, and errors go to the second one.
The engine took care of making sure the throttle was set to give the appropriate amount of power, the mixture was set to make sure the engine didn't cool too quickly or overheat, and the propellor pitch was adjusted for optimum power, speed, and noise. You'd think that pilots would love something like this that. I sure would. Nope. Many pilots wrote Letters-To-The-Editor of all the flying magazines complaining that the manufacturer was taking away their control of the aircraft. The Porsche aircraft engine was withdrawn from the market after a few years and very few aircraft sales.
At least part of this, the constant speed propeller is in widespread use. Although, especially in a multi-engine config, I'd want one with the ability to feather the propeller in case of an engine out (to lower Vmc). I'd also want to make sure the one I used allowed me to dive-start an engine.
General aviation's biggest problem has been total technical stagnation which the manufacturers have regularly blamed on lawsuits (when they improve something and it ends up killing someone, they can expect a lawsuit from that improvement). The only noticeable R&D has been from the uncertified Experimental category (although occasionally someone will take an experimental design and push it through certification so they can manufacture it).
Rubbish. Look at the nuclear bombings of Nagasaki or Hiroshima or the firebombings of Germany or the V2 attacks on London. Those were all attacks on civilians that were legitimate military strikes.
World War II was regarded as a "Total War" - that is, both sides devoted the entirety of their nation's resources to victory. Everyone planted crops in their yards to help feed the army. The schoolchildren were being raised to join the army. The automobile manufacturers were building tanks and jeeps. The housewives were riveting ships together. To each side, no one on the other side was a bystander and no one was innocent.
I sure hope it never comes to that again. Last time both sides were decimated. Next time they'll both be obliterated.
What purpose does that link serve? The controversy section mentions only anarchism.
You asked "By what principles and rationale was this concluded?" - If the only thing you can walk away with from reading an article covering a history of the very philosophy you are espousing (without knowing it, apparently) is some mumbling about anarchism, then you need to do some further reading. Pick your own links this time.
By what principle or rationale do you come to this conclusion?
For starters, money is a human invention.
What, again, does this have to do with businesses needing to be restricted for reasons unspecified by you?
You were asking "then from where does this magical ability to avoid reality come?". It was not an argument that businesses need to be restricted - it was an argument that businesses can and are restricted. Those restrictions are today's reality - not an avoidance of it. You want to open a bank in this country? You have to agree that the FDIC can put you into receivership if you fail. You want to prepare food for people? You have to wash your hands when you finish in the bathroom. You want to sell shares of your company publically? You have to report your finances. You want to lay off half the town that works for you? You pay out a lot of extra severance. You want to make and sell cars? They have to meet emissions and crashworthiness standards. These are all laws that protect consumers by regulating business, and there are thousands more.
Denying the nature of man does not invalidate his rights. Those rights determine whether something is just or not.
Obviously, laws and rights are very different things. I was only talking about the former.
You keep referring to this collective fantasy we call "money" as "reality". Money is not a manifestation of some natural physical law. It is entirely arbitrary.
Is a law justified simply by its very existence?
From a purely technical point of view, laws are ultimately justified by force or the threat of force, not necessarily by any moral code. It's also the implied threat of the force of the citizens that ultimately keeps a government in check.
If not a right, then from where does this magical ability to avoid reality come?
In the US, our legal system has generally come to the conclusion that market forces alone are not sufficient to keep the power of large corporations in check. As a result, there are numerous state and federal consumer protection laws on the books for everything from usury to warranties to fraud to antitrust (Uniform Commercial Code, Magnusen-Moss Act, Sherman Act, etc.).
I'm not a lawyer and I'm not familiar with enough of these laws to speculate which ones the judge might apply in this case.
The article was light on details.. why did they decide that fees that are clearly stated in a contract before people entered the contract are now illegal?
Because cell phone companies aren't willing to negotiate contracts with consumers, and the few cell phone companies that consumers can choose from all have equally evil contracts.
Also, contracts are only valid if there's a quid pro quo - if there's no prorating, the judge may take that into account.
In the end, contracts are only binding if they are legal - you can't sell yourself into slavery, you can't contract out a hit on someone, etc etc.
Second, try taking off or landing a Cessna in your driveway.
Unless your driveway is in the sticks, you'll only be able to take off and land this thing there once. After that, the neighbors will have taken out restraining orders preventing you from operating it near them.
The concept of a personal flying machine (e.g. Cars, Bikes, Jet Packs) is two fold at the moment.
1) Energy / Power (inc. Storage & Delivery)
2) Safety
Why, again, does this need to be something you carry on your back instead of something you step into?
Gyrocopters can be made very small, they can land almost vertically (and in a controlled manner with the engine out), the ones with pre-rotators and collective controls can take off near vertically (the ones that can only do the former need only a few hundred feet, the ones that can do neither need less than 1000 feet), they'd be a lot quieter, reasonably fuel-efficient, and less dangerous than any incarnation if this thing, which would fall like a rock on engine failure. Some of them even qualify as ultralights which means that no pilot license is needed for them.
That brings up an interesting question about using car batteries since they all use 12volts. So is it safe to actually hook one up to the standard UPS provided the cables are rated for it? A typical UPS battery is only like 7 Amp-Hours units while a car battery is like 40+ Amp-Hours.
I wouldn't stick significantly larger batteries on any UPS that doesn't have external battery connections. The reason is that the heat sinks on the charger and inverter may be designed to only handle full load for a certain amount of time - giving them more battery power to chew on may cause them to overheat. You may be able to make it safer by adding active cooling, but it's still at your own risk.
Anything with external battery connections most likely has continuous-duty parts inside.
Not to mention, finding capacitors with a high enough voltage rating and low enough height limits you to a much lower capacitance than is ideal.
That's true. You can run them in series, but it's the same energy density either way (and getting too close to the voltage limit will shorten capacitor life).
And I can see that my tongue in cheek wasn't obvious enough.
Nor was mine.:) Although I haven't seen either myself, I'm sure they've both actually been implemented somewhere in the world (for things besides the classic desk calculator).
However, the power draw on the board was around 200 Watts; being able to supply that much power for that long in a fairly compact form factor was a huge hurdle.
Of course I don't know the voltage tolerances you were working with in your design, but many PCs survive even 200ms just fine, although they store most of their power in (fairly small) inductors. If your design voltage is 5V and your draw is 40A, then you need 12.5mH to store 10 joules (although you'd need several times more than that because you need power within tolerances for that entire 50msec) and a freewheeling diode to source those electrons from ground. One bad thing about inductors is they need special consideration to prevent voltage spiking or arcing on load disconnect.
Worse than that, the cheap ones don't output sine waves, they output square waves.
filtering technology like you find in expensive powerbars
If you get these pieces separately, do not plug them into each other! The capacitors/inductors on the filter will have to eat about one-third of the UPS's output power, and chances are they don't have heat sinks capable of it. One third of a 1500W UPS is 500W, which is the same thing as one kitchen stove burner on medium-high.
All you need to do is have the grid power feed some high wattage light bulbs. And near the light bulbs is some solar cells.
You now have a 1% efficient power supply.
A slightly more practical option (with better isolation than a standard electromagnetic transformer, but unfortunately also some inductive effects) would be to couple two motors with an insulative shaft.
What would be involved in changing the inclination of the ISS orbit to match that of the solar system?
Earth is 23.5 degrees from the ecliptic, so in theory (maybe someone else can correct me here) at some point in the year, ISS will be 51.6-23.5=28.1 degrees off of the plane of the ecliptic. ISS orbits at 7.68km/s, so an off-the-cuff calculation would be 2*sin(28.1/2)*7.68km/s = 3.73km/s of delta-V
about half the energy of launching it all in the first place. If my assumption is wrong that at some point of the year ISS is only off 28.1 degrees from the ecliptic, and you have to go the full 51.6 degrees, that's 2*sin(51.6/2)*7.68km/s = 6.68km/s - almost as much energy as launching it all. This also assumes that you can do the course correction ballistically - with an ion engine it'd take dozens or hundreds of orbits instead of a partial one, so the math would be completely different. With a 4500m/s exhaust speed chemical engine (f.e. the SSME), 3.73km/s delta-V requires a 2.26 fuel-to-final-mass ratio. If you didn't need to increase the mass of the ISS at all for the rocket engines and fuel tanks, then you'd only need 1070000kg of fuel. A Saturn V can lift 118000kg to low earth orbit, so you'd only need 9-10 successful lifts for the fuel itself. Should be a piece of cake.
If you're going somewhere else with the ISS, then you wouldn't do that change at low earth orbit - higher orbits are slower, so it takes less delta-V up there.
The idea of the sacrificial anodes is that by simply being attached to the metal of the ship it gets dissolved rather then the important stuff like the hull.
Anything lower on the galvanic series than your primary structure can be used (although going too far down the list means the chemical reactions can happen too quickly, peeling off paint, etc).
As a Federal Agency, the FCC can ask for proprietary information & trade secrets, but they cannot disseminate that information to the public.
What does being a federal agency have to do with it? If I ask for and get proprietary information and trade secrets, I can disseminate that information all I want. Unless I signed an NDA. And given the FOIA, wouldn't an NDA signed by a government agency be worthless?
I know I'm replying to myself a third time, but since I know someone will shout "it only has a 400 yard range!" - well, figure you're going to be in very low earth orbit, maybe 200km. (400m/200000m)^2 =.000004. 2^-18 =.0000038. Ergo, you'll need at least a 3*18 = 54dB gain antenna to pick this up. That would be quite large (especially for 2 meters), but still reasonable.
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This varies wildly. It's possible to make it about 90% efficient if you spend $10 in parts, but most manufacturers want to put out something cheaper than that. Many wall warts are less than 50% efficient (you can check by reading the input and output ratings on the label).
Same as the MPG of an idling car. Zero divided by any number is still zero. What you want to know is the no-load power. Get a Kill-A-Watt, buy one of these things, post your review on the web somewhere, or find someone to do it for you.
Alternatively, just put your hand on it and see if it feels warm.
I'll assume you meant 75% efficiency - we usually measure efficiency by how much energy is not wasted as heat.
I don't know where you got this from. There is no such thing as a 20% efficient air conditioner on the market. Most are around 50% thermodynamically efficent which does not mean they use 2 watts to move a watt out of a room (look up Carnot cycle). An old clunky 10 SEER air conditioner uses 1 watt of electricity to move 2.92 watts out of a room. A modern 15 SEER AC unit uses 1 watt to move 4.39 watts out of a room.
The air conditioner in your example needs 6 to 9 watts to cool 25 watts - not 125.
"Most truths are so naked that people feel sorry for them and cover them up, at least a little bit."
-- Edward R. Murrow
I would rather the computer have two screens with the second one reserved entirely for presentation - BIOS POST, bootup, desktop, and errors go to the second one.
At least part of this, the constant speed propeller is in widespread use. Although, especially in a multi-engine config, I'd want one with the ability to feather the propeller in case of an engine out (to lower Vmc). I'd also want to make sure the one I used allowed me to dive-start an engine.
General aviation's biggest problem has been total technical stagnation which the manufacturers have regularly blamed on lawsuits (when they improve something and it ends up killing someone, they can expect a lawsuit from that improvement). The only noticeable R&D has been from the uncertified Experimental category (although occasionally someone will take an experimental design and push it through certification so they can manufacture it).
World War II was regarded as a "Total War" - that is, both sides devoted the entirety of their nation's resources to victory. Everyone planted crops in their yards to help feed the army. The schoolchildren were being raised to join the army. The automobile manufacturers were building tanks and jeeps. The housewives were riveting ships together. To each side, no one on the other side was a bystander and no one was innocent.
I sure hope it never comes to that again. Last time both sides were decimated. Next time they'll both be obliterated.
Then please ask someone else.
You asked "By what principles and rationale was this concluded?" - If the only thing you can walk away with from reading an article covering a history of the very philosophy you are espousing (without knowing it, apparently) is some mumbling about anarchism, then you need to do some further reading. Pick your own links this time.
For starters, money is a human invention.
You were asking "then from where does this magical ability to avoid reality come?". It was not an argument that businesses need to be restricted - it was an argument that businesses can and are restricted. Those restrictions are today's reality - not an avoidance of it. You want to open a bank in this country? You have to agree that the FDIC can put you into receivership if you fail. You want to prepare food for people? You have to wash your hands when you finish in the bathroom. You want to sell shares of your company publically? You have to report your finances. You want to lay off half the town that works for you? You pay out a lot of extra severance. You want to make and sell cars? They have to meet emissions and crashworthiness standards. These are all laws that protect consumers by regulating business, and there are thousands more.
Obviously, laws and rights are very different things. I was only talking about the former.
I suppose this is as reasonable a writeup as any.
You keep referring to this collective fantasy we call "money" as "reality". Money is not a manifestation of some natural physical law. It is entirely arbitrary.
From a purely technical point of view, laws are ultimately justified by force or the threat of force, not necessarily by any moral code. It's also the implied threat of the force of the citizens that ultimately keeps a government in check.
In the US, our legal system has generally come to the conclusion that market forces alone are not sufficient to keep the power of large corporations in check. As a result, there are numerous state and federal consumer protection laws on the books for everything from usury to warranties to fraud to antitrust (Uniform Commercial Code, Magnusen-Moss Act, Sherman Act, etc.).
I'm not a lawyer and I'm not familiar with enough of these laws to speculate which ones the judge might apply in this case.
Because cell phone companies aren't willing to negotiate contracts with consumers, and the few cell phone companies that consumers can choose from all have equally evil contracts.
Also, contracts are only valid if there's a quid pro quo - if there's no prorating, the judge may take that into account.
In the end, contracts are only binding if they are legal - you can't sell yourself into slavery, you can't contract out a hit on someone, etc etc.
Unless your driveway is in the sticks, you'll only be able to take off and land this thing there once. After that, the neighbors will have taken out restraining orders preventing you from operating it near them.
Why, again, does this need to be something you carry on your back instead of something you step into?
Gyrocopters can be made very small, they can land almost vertically (and in a controlled manner with the engine out), the ones with pre-rotators and collective controls can take off near vertically (the ones that can only do the former need only a few hundred feet, the ones that can do neither need less than 1000 feet), they'd be a lot quieter, reasonably fuel-efficient, and less dangerous than any incarnation if this thing, which would fall like a rock on engine failure. Some of them even qualify as ultralights which means that no pilot license is needed for them.
I wouldn't stick significantly larger batteries on any UPS that doesn't have external battery connections. The reason is that the heat sinks on the charger and inverter may be designed to only handle full load for a certain amount of time - giving them more battery power to chew on may cause them to overheat. You may be able to make it safer by adding active cooling, but it's still at your own risk.
Anything with external battery connections most likely has continuous-duty parts inside.
That's true. You can run them in series, but it's the same energy density either way (and getting too close to the voltage limit will shorten capacitor life).
Nor was mine. :) Although I haven't seen either myself, I'm sure they've both actually been implemented somewhere in the world (for things besides the classic desk calculator).
Of course I don't know the voltage tolerances you were working with in your design, but many PCs survive even 200ms just fine, although they store most of their power in (fairly small) inductors. If your design voltage is 5V and your draw is 40A, then you need 12.5mH to store 10 joules (although you'd need several times more than that because you need power within tolerances for that entire 50msec) and a freewheeling diode to source those electrons from ground. One bad thing about inductors is they need special consideration to prevent voltage spiking or arcing on load disconnect.
If you get these pieces separately, do not plug them into each other! The capacitors/inductors on the filter will have to eat about one-third of the UPS's output power, and chances are they don't have heat sinks capable of it. One third of a 1500W UPS is 500W, which is the same thing as one kitchen stove burner on medium-high.
You now have a 1% efficient power supply.
A slightly more practical option (with better isolation than a standard electromagnetic transformer, but unfortunately also some inductive effects) would be to couple two motors with an insulative shaft.
Earth is 23.5 degrees from the ecliptic, so in theory (maybe someone else can correct me here) at some point in the year, ISS will be 51.6-23.5=28.1 degrees off of the plane of the ecliptic. ISS orbits at 7.68km/s, so an off-the-cuff calculation would be 2*sin(28.1/2)*7.68km/s = 3.73km/s of delta-V about half the energy of launching it all in the first place. If my assumption is wrong that at some point of the year ISS is only off 28.1 degrees from the ecliptic, and you have to go the full 51.6 degrees, that's 2*sin(51.6/2)*7.68km/s = 6.68km/s - almost as much energy as launching it all. This also assumes that you can do the course correction ballistically - with an ion engine it'd take dozens or hundreds of orbits instead of a partial one, so the math would be completely different. With a 4500m/s exhaust speed chemical engine (f.e. the SSME), 3.73km/s delta-V requires a 2.26 fuel-to-final-mass ratio. If you didn't need to increase the mass of the ISS at all for the rocket engines and fuel tanks, then you'd only need 1070000kg of fuel. A Saturn V can lift 118000kg to low earth orbit, so you'd only need 9-10 successful lifts for the fuel itself. Should be a piece of cake.
If you're going somewhere else with the ISS, then you wouldn't do that change at low earth orbit - higher orbits are slower, so it takes less delta-V up there.
Anything lower on the galvanic series than your primary structure can be used (although going too far down the list means the chemical reactions can happen too quickly, peeling off paint, etc).
"69 with two fingers up your ass"
What does being a federal agency have to do with it? If I ask for and get proprietary information and trade secrets, I can disseminate that information all I want. Unless I signed an NDA. And given the FOIA, wouldn't an NDA signed by a government agency be worthless?
I know I'm replying to myself a third time, but since I know someone will shout "it only has a 400 yard range!" - well, figure you're going to be in very low earth orbit, maybe 200km. (400m/200000m)^2 = .000004. 2^-18 = .0000038. Ergo, you'll need at least a 3*18 = 54dB gain antenna to pick this up. That would be quite large (especially for 2 meters), but still reasonable.
This isn't it but it does fit the bill.