What about living directly under a ~40kV power line?
I'd be more concerned with the electric field than the magnetic. And I'd be more concerned with ozone and ions from the coronoa discharge than with the electric field. But I wouldn't be very concerned about any of 'em.
There were some studies purporting to show problems. But one set turned out to be using faked data. Others neglected to account for the fact that living near substations or highlines is strongly correlated with lower income - which has LOTS of powerful nasty effects on health.
Even if there was an effect on cancer rate, I'd be more inclied to look for PCB exposure from leaking transformers or another chemical problem than some electrical phenomenon. Your body fluids are very conductive, which keeps the E-field low internally. And changing your orientation with respect to the earth's field as you walk around creates more delta-H than you're likely to get from power transmission equipment, unless you like to use distribution transformers for jungle-jims.
But if you DO live under a high-line, you might want to get an 8-foot fluorescent tube and wave it around in the yard. E-field under those, from end to end of a long tube, is often enough to ionize the mercury vapor and make it light up.
If it works, put a few of 'em in protective plastic covers (to avoid breakage) and plant them around your house for yard lights. B-) (The power company might accuse you of stealing their power. But a judge has already told 'em that if they can't keep it in their lines it's their tough luck when sombody salvages a bit of it.)
It is not a static magnetic field. A 60 Hz magnetic field is also a 60 Hz electric field. The radiation field from a dipole drops of with the inverse of distance squared. The intensity drops off with the fourth power.
It has been a few years since I studied this material. Please let me know if I am in error.
I believe you are. It's quadripole fields that fall off with inverse fourth.
Dipole fields fall off with the inverse cube, as I recall. Inverse square for the individual poles, pluse an extra inverse first-power for the separation between the poles. (Quadripole fields get an extra inverse first-power for the separation for their component dipoles in the other dimension.)
Let's assume for now that the leakage from the motor is mostly a dipole field. (CAN'T be a monopole. B-) ) For a DC field, or the "near field" of an AC field, the dipole field dominates - and it falls off inverse cube. Get two inches from the shaver and the field is 1/8th what it was at one inch. Four inches makes it 1/64th, and so on. Falls off REALLY fast with distance.
As you get farther out the changing magnetic field creates a changing electric field that in turn supports the changing magnetic field (as long as they're both propagating at lightspeed). Then you have an electromagnetic wave, detached from its launcher. This falls off with inverse square.
Under a quarter wavelength the near-field is so dominant you can pretty much ignore the far-field. Over a wavelenghth or so away the situation is reversed (unless your driving element is large compared to a quarter wavelength).
So what's the wavelength of 60 HZ? About three thousand miles.
I don't think we need to worry about the far field. B-)
So figure inverse cube falloff - or faster if the motor's magnetic leakage has more than two poles.
(This is why you need to get REALLY CLOSE to a magnet to erase your credit cards.)
Back in the '60s or so, Irv Hoff (who later was instrumental in developing ham packet radio) was a radioteletype ham. 110-bps ASCII was around and in heavy use for landline teletype and those new-fangled minicomputers. But hams were still limited to 60-bps Baudot (5-bit) teletype and obsolete machines. (This was apparently because the FCC didn't have the budget for buying new moniitoring equipment, so it wouldn't legalize the new coding scheme and speed.)
Irv wanted to go faster. Morse wasn't speed-limited and FSK modulation was allowed. So he built a couple copies of a device to convert ASCII to and from morse and send it either at 110 baud or (using tape) some truly hysterical speed.
Of course the FCC heard the high-speed signals that they couldn't translate and came after him. And he said "But they're just morse! Tape them and slow them down and you'll hear it."
So the FCC did. And shortly threw in the towel and legalized 110-baud ASCII.
Which was the whole point of the exercise. B-)
Now I think Irv may have came up with some arbitrary codings for the ASCII symbols that weren't part of Morse during that exercise. If so, and if they were easy for humans to use, it might have made sense to standardize those.
That would be "mayday mayday mayday [destination call sign] [your call sign] [emergency description] [action taken] [position of vehicle] [other information]" (for aircraft at least).
Essentially the same for boats, if life is at risk.
Lower levels are much the same but with "mayday" replaced by:
- "pon pon" ("pahn pahn") for less immediate problems (i.e. slowly taking on water, bilge pump out, can probably make port, but could somebody be ready to help out?) or
- "security" ("see-cure-ih-TAY" - all three signals come from French) for problems (i.e. hazards to navigation) that don't require assistance but should be watched for.
this thing would be more painful to work on chip to chip communications since you don't know if the other chip is Z or the logic state you are receiving simply corresponded with your current driving logic state. (I suppose one can always send a enable / disable signal similar to DQS along with a dataline to indicated if it's active)
You have two misconceptions about the scheme in question:
1) There is no "Z" state. Both sides are ALWAYS driving.
2) You don't have to stop driving the line to receive what the other side is driving toward you.
This is essentially the same hack that lets a telephone send energy at the same band of frequencies in both directions simultaneously, on a single pair of wires:
- You terminate the line at, or near, its characteristic impedence, and so does the device at the far end.
- You inject a current into the line/terminator junction (or, equivalently, shift the voltage at the "cold" end of the terminating resistor) to send.
- You compare the voltage on the pin (or current through the pin, or current through the terminating resistor) to what you expected to see if the far end was at a no-current-injected (or terminator "cold" end at ground) state. The difference is the signal being injected at the far end.
The wire is being driven at both ends at all times (no Zs). You can always tell what the far end is sending, regardless of what you're sending.
If you chose to send by injecting a voltage at the "cold" end of the terminator, you dissipate no power when both ends are sending the same value. You dissipate a significant amount when both ends are sending opposite signals. But you also dissipate the same amount if the transmitting ends of two separate wires are switched - for the time it takes the signal to propagate and the reflection to come back. If the separation between the transmitter and receiver is more than half the length of a bit time, the quiescent state has both sides driving the same value, and the two ends drive opposite about as often as same, it's a wash.
the concept is indeed pretty cool, though you'll need some tough lil drivers that can handle incoming voltage swings while it's driving.
No you don't. You already need to drive a line that's got a charge on it from the stuff you previously drove onto it. This doesn't change that. The local end just sees the far end as being terminated by a resistor to a voltage that is either low or high, rather than being terminated by a resistor to a constant voltage.
Driving both ways simultaneously, though, is very cute.
The downside is the need to daisy-chain. That means you're driving multiple lines at 3.6 Gbps on EVERY chip, ALL THE TIME. That's a LOT of power. Even if you interrupt the daisy chain at the selected chip (and arrange things so that the quiescent states of the transmitters at both ends of an idle line match) it's still a lot of power unless you localize most of your memory access to the closest chip.
1... b (1): a government in which supreme power resides in a body of citizens entitled to vote and is exercised by elected officers and representatives responsible to them and governing according to law
This is the definition applicable to this subthread, where it is the institutional structure of the government that is being discussed.
In such a context it is the definition of the technical term, rather than other common uses of the same word, that matters.
I agree with what you say, but that's exactly where the article is lacking - even if this technology could be made production-ready in the next few years, it still won't make homes run stand-alone because the other technologies you mention aren't really consumer-friendly (doesn't mean they don't exist, or that some people don't use them of course).
I completely fail to understand your point.
Batteries for local storage, combined with power sources whose available power doesn't match the load curve, is ancient stuff. Virtually EVERY off-grid home power system uses them. They've been around since patent windmills were first combined with generators - before rural electrification. The only major changes to the technology in the last decades are semiconductors making inverters cheap enough that standard AC appliances become cost-effective and the unified inverter/charge controller (which is just a convenience). Consumer off-grid systems are comon enough to keep the innovations coming, the bugs shaken out, and the industry operating at a reasonable economy-of-scale.
With constant but below-peak-load sources (like water), the batteries only capture unused power in excess of demand to cover later beyond-generation peak loads. Ditto if the supply is somewhat controllable but with a limit below peak load (i.e. fuel-thermopile, start/stop engine/generator, dam/valve/turbine water).
With inherently intermittent sources (like solar or wind) they perform the same function, but have the additional feature of filling in the dips and disappearances of the variable power source.
You can plug in any energy supply and get the same sort of results. (A kilowatt reformer/fuel cell combo is just a variant on a dam/valve/turbine, where you use the batteries to cover peaks beyond your capability and sudden surges, and throttle back the generation to save the resource for later when your batteries are full and your load is less than generation capacity.)
So the availibility of reasonaby efficient, moderately low maintainence, peaking storage is a given, and the generation system can be examined in isolation (except for taking into account the cost and efficiency of available storage/peaking systems when examining the cost of the device and its operation).
Yes, it would be nice to have a more-efficient, potentially lower maintainence, storage system (such as superflywheels.) And the generation system's own physics may present additional opportunities for storage (such as hydrogen storage between the reformer and the fuel cell). But that doesn't mean you need to come up with a new, unique, invention to deal with peaking for each generation approach.
As a practical measure I'm sure the researchers know that running on 1KW per day isn't practical - they live in MN like me, so at this time of year homes will have a 0.8KW blower motor running for much of the day to keep the house warm! And during the summer you can add an air conditioner to that
So that just means you'll need a larger model, or more than one of the standard size (if manufacturers only build a small number of sizes, and you stick with forced-air).
But I doubt that there is anything magic about that 1kw exemplar that would make it difficult or more expensive to produce other sizes. Seems to me that they're just describing it in terms of a typical instalation size, for an "average" home's electric power usage.
From the article: "The cell could produce 1 kilowatt of power, nearly enough for an average home."
A bit of googling (http://www.arctic-cat.com/generators/wattage.asp) turns up numbers showing that an iron takes about 1.2KW, or just over 1KW for a toaster.
And do you run your iron or toaster 24/7? I doubt it. (For starters, that's like running a large electric space heater 24/7.)
A typical home runs roughly a KW average - 24 KWhr/day.
So almost enough for an average home, so long as I wander round the house turning off everything else before flattening my shirt or browning some wheat. That's handy.
And that's not the way you'd do it. You'd run the reformer/fuel cell to generate power to keep your batteries charged.
- When you're pulling over a KW, all the power from the fuel cell goes straight through the inverter to run your house, avoiding the losses of a charge/discharge cycle, while the batteries (or superflywheel if they ever become practical) provide the surplus.
- When you're pulling less, the fuel cell's surplus goes to recharge the peaking batteries (or spin up the flywheel). As they approach full charge, the fuel cell starts cutting back production.
An alternative would be to use an oversize fuel cell and store the hydrogen. But that would increase the fuel cell losses - which are probably worse than storage battery charge/discharge losses - and the larger fuel cell would also be more expensive. Battery peaking is probably better for both total system and per/KWhr operating cost than an oversize fuel cell and a hydrogen storage system.
Is this better/more efficient... than an ethanol powered engine?
Yes. (Though not for the reasons given by the other postings.)
Burning a fuel in a heat engine gives you, at the absolute best, slightly less than the carnot-cycle efficiency applied to the temperature difference between the flame and the ambient temperature.
Essentially all the energy from the chemical reaction goes into heating the working fluid (which, in an internal-combustion engine is the air and fuel mixture itself - pretty efficient compared to some alternatives, though there's a lot of nitrogen along for the ride and that limits the temperature). But only about a third, max, of the energy of that excess heat is converted into useful work by the heat engine, while the rest just heats the engine and its surroundings.
A fuel cell, on the other hand, can potentially extract essentially ALL of the energy of the chemical reaction as electricity. (Some still comes out as heat. But it does a LOT better than a heat engine.)
A combustion engine gets to use all the heat of burning both the hydrogen and the carbon to oxides, minus the heat necessary to break the hydrocarbon into free hydrogen and carbon (and the oxygen molecules into free oxygen).
The reformer loses some of the energy of burning the carbon and uses some of it to free the hydrogen from the carbon and deliver it as more losely bound H2. Then the fuel cell delivers the energy of burning H and O to H20, less the energy of breaking up the H2 and O2 into free H and O, and less some efficiency losses.
Virtually ALL the energy in burning a hydrocarbon comes from burning the hydrogen, so losing part of the energy of burning the carbon (in the reformer/fuel cell case) is spilling a few drops from the bucket. Losing all but the carnot cycle portion of both the carbon and hydrogen's contribution (in the heat engine case) is dumping over 2/3s of the bucket.
Thanks. But I'll let the FSF's lawyers worry about that.
"MS is alleged to have a record of stealing other people stuff."
Never heard of them stealing source code. And this isn't all source anyway.
Starting with DrDOS, if not earlier. People have claimed that MS engages in contracts with other companies (many instnaces), then pulls stunts that amount to contract violation, in such a way that MS ends up with the other company's IP while the other company ends up dead or wounded and with no significant benefit.
The idea of putting multiple scripts into a singe file is useful, and it's been done.
But that's not what they're patenting (or at least not what the previous poster is describing).
The idea is not to tar up files. The idea is to have a set of scripts in multiple languages in one file, along with associated metadata, so the metadata interpreter can automatically select one that one of its associated interpreters understands, allowing automatic execution of a version of the script if any version is executable on the local environment.
Are you saying there is something patent worthy about using XML instead of HTML,.zip,.tar, etc?
I'm making NO claims about its patentability. I'm just pointing out that zip, tar, etc. are NOT prior art for the claim described above.
in other words, using XML to keep several languages' versions of one script.
I don't really see the point.
It lets authors write a script that will work if the target machine has ANY of the script interpreters available.
Yes, it's useful. What if there are only five interpretrs out there that can do the job, and ALL of them are proprietary? Nearly everybody's browser has at least ONE of them. But even the most popular interpreter is only available on a third of the people's browsers. Pick a single language, only a third (or less) of your potential audience can use the app.
So do you pick VBScript? Or Python? Or Perl? Or do you do one for EACH, bundle them up, and let each user's browser pick an interpreter?
Now you CAN hack it by including all the scripts and trusting the browser to ignore whever it can't understand. But then if it understands more than one of the languages it runs the script more than once. Oops!
This provides a formalism for telling the browser that this SET of scripts all do the same thing, so it should pick and run just one of them.
Of course to make this useful it will have to be adopted more generally. Which might push Microsoft into making it available free, and encouraging its adoption.
There are plenty of extremely portable languages, and what happens if the versions in the XML file fall out of synch?
It breaks.
What happens if you modify a script and induce a bug? Ditto. So what?
(Of course this also creates another way for companies to write tools that produce code that runs correctly on their own browser products and screws up on those of others. B-) )
I doubt that Microsoft intentionally planted this snare but if any future open source project even vaguely resembles this leaked code I have no doubt that Microsoft will open their full arsenal of lawyers.
On the flip side:
A comparison of the code against that of open source projects could be used to detect places where MS developers have included open source code in MS products. With this as a starting point, a suit's discovery process could bring it out in a form that could be used as evidence against MS.
(Of course the leaked code should be analyzed by a consulting organization separate from the open source developers, to keep developers and their servers clean for defense against later claims from MS.)
MS is alleged to have a record of stealing other people stuff. Will be interesting to see if it's true, provable, and something can be done as a result.
I'm surprised nobody has sent them patches to fix security issues yet.
I'm not. (Though I WON'T be surprised if somebody sends 'em a patch anonymously. B-) )
Anybody who sends a fix in a tracable way - and lets the rest of us know they did it - is likely to be sued, or prosecuted, for having a copy of the source. So why risk it?
Not even LEDs are 100% efficient. However, for an optical system, the heat production is related to the duty cycle of the lamps, rather than the switching speed, so the heat production should remain constant regardless of clock speed.
That's true of the heat production in the guts of the lamp itself (at a given light intensity). But there are other factors.
On the one hand, this means you don't need to improve cooling to overclock. On the other, it means that you can't improve the overclock level with improved cooling.
Most of the heat loss in a circuit comes from the I-squared-R losses of the currents needed to charge and discharge the stray capacatance of the wiring (even the tiny traces on the ICs) and the space-charge of the devices.
In particular, if the wire has any significant length, you need to run that current through a series resistance (at least at the driving end) matching the impedence of the wire, in order to produce a nice waveshape at the far end and prevent "ringing" as the signal bounces back-and-forth (which would degrade the waveshape at the inputs to far-end gates and make the signal both more sensitive to noise AND more generative of noise to interfere with its neighbors.)
With CMOS you only pull power (except leakage power) when you CHANGE the state of a signal. But when you do, you have to charge, or discharge, the signal wiring through that matched resistance. The impedence of the wiring doesn't change a lot with technology and speed. So with a given length of wire, you have a given amount of energy dropped every time you switch it. Switch it twice as fast, generate twice as many pulses of heat.
New generations of semiconductors fight this in three ways:
- Shrink the components (so they have less stray capacatance to charge and discharge).
- Shorten the signal runs by making the components smaller so they can be closer together (reducing the stray capacatance of the lines). (But this doesn't help for signals that HAVE to cross the chip, or leave it.)
- Lower the power supply voltage (so you don't have to swing it as far. Current goes up with the the voltage, heat loss with the square of the current.) (For signals that leave the chip this may be harder to do than for signals that stay on it - due to external interference.)
For switching a light-emitting device you still have to charge and discharge the capacatance of the device itself and the wiring to it. Switch it faster and IT doesn't heat up much more. But the driver circuit does.
By putting a light modulator on the chip, Intel's new technology wins in two ways:
- You don't have to rapidly switch the power to the laser (which involves switching a LOT of current through an impedence-matching resistor).
- You don't have to run a microwave-speed signal through a long resistive wire, which degrades its waveshape and also produces still more losses. Instead you switch a low-power, short-range, on-chip wire to a low-capacatance active region on the on-chip modulator. Switching losses are relatively small, comparable to those of a gate-to-gate internal signal in the same chip.
Re:Do you have ANY idea how CHEAP it is?
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Airlines do not need fat pipes.
Yes, but this is a service of the airPORT, not the airLINES. What pipes does the port itself have?
But let's assume, for the moment, that the airport's own feed is either inadequate or unsuitable for sharing (i.e. airline safety issues). OK, you need to install a new feed.
Let's make it a really fat feed. Let's say that it's SO fat that it costs TEN THOUSAND DOLLARS per MONTH - or just enough less that adding in maintainence on the hotspots brings it to that.
For SFO that works out to under THREE TENTHS OF ONE CENT per passenger-trip.
Again, I doubt anyone will feel a pinch.
Do you have ANY idea how CHEAP it is?
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There are at least two ways the airport can pay for this. One is to include it in the fees charged to the airlines: landing fees, rental of hangar and counter space, various other services. Another is to include it in the rent paid by shops and restaurants.
But do you have any idea how CHEAP this would be in an airport environment, if it's NOT being metered?
Figure a couple dozen wireless routers (at $100 each). An fat pipe internet feed (which they probably already HAVE, and can piggy-back on for essentially free if they give the hotspots a lower priority), a bit of cat-5 strung through the ceilings, a couple of hubs, and a port on the router (which they ALSO already have). Call it a one-time investment of a few grand. (Costs more for labor to install it than to buy the parts.)
Recurring costs of less than a grand a month or so for maintainence. Call it two grand if you're actually PAYING for the bandwidth. Power for the machines is below the noise.
HOW many passenger-trips through a major airport in a month? (SFO was 41 million per year in 2000, almost three and a half MILLION per month. $2*(10**3) / 3*(10**6) = $0.000666... seven ONE HUNDREDTHS of ONE CENT per passenger-trip.
Somehow I don't think anybody will feel the pinch.
Same reason there's no ticket taker in elevators.
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It makes sense because the incremental cost of providing the service is probably lower than the cost of the soap (lots in my flight bag) and the capital is less than the cleaning budget for the toilets for a day or two.
It also makes sense because providing the internet feed is dirt cheap, while trying to meter it and collect fees is NOT.
It's called a "marginal service" - like the shaver outlet in the bathroom (without a meter and coin slot), providing lighting (rather than requiring you to bring your own flashlight), or the free elevators (without a ticket taker). It's MUCH easer and cheaper to include the cost of the service in the overhead cost of the environment (and the goods and services you buy there) than to try to bill for it specifically.
Closer to the shaver outlet than the elevator, by the way. Unmetered internet service is dirt cheap to provide. Installing and maintaining elevators is DARNED expensive.
Because every so-called communist government has in practice been an Oligarchy. Contrary to American knee-jerk anti-communist propaganda there are no commies and never will be.
Yeah, we've heard that all before.
Real communism hasn't been tried yet. The people calling themselves communists are actually x.
Real socialism hasn't been tried yet. The people calling themselves socialists are really y.
Real capitalism hasn't been tried yet. The people calling themselves capitalists are really z.
Real Christianity hasn't been tried yet.
Real Islam hasn't been tried yet.
and on, and on, and on.
I could care less about what a system is SUPPOSED to be IN THEORY, if only people would do what the theory says. Some people will always be selfish, corruptable, and/or prone to ideological confusion. And you're not going to change that - at least not for several lifetimes (after which there's the question of whether it even matters, since what you're dealing with is no longer human beings). So the HOLES in the theory, and the ways it can be subverted, are all part of the system.
From my standpoint, real FOO is what you get when you try to implement system FOO with real people.
This sounds like a civilian version of the GPS/lidar/etc/binoculars recently used by the military for spotting targets for artillery and other attack missions.
Look at the target, center the crosshairs, read the *target's* GPS co-ordinates (or dump them into the battle net).
Every time science comes up with a new form of evidence (or even a new way of analysing old techniques), someone gets convicted because of a persuasive argument which blinds the jury with science.
It's happened with DNA, fingerprints, computer cracking.... Hopefully the technology is eventually ironed out such that this stops happening.]
Meantime, this is cold comfort to victims of such miscarriages of justice, or their families.
But it's two edged:
DNA evidence is now being used to clear people who have spent decades in prison for crimes they didn't commit.
At least if you have the death penalty the vctim of the miscarriage of justice (eventually) isn't in too much of a position to care.
And it puts them beyond reach of ANY correction, when technology advances to the point where it can discover and prove their innocence, winning them release (and millions in restitution for the false imprisonment).
See The Innocence Project for more.
I, at least, am totally opposed to the death penalty. Not because the crooks don't deserve it - most of 'em do. But because it's administered by a government, with at least the usual levels of incompetence, corruption, and misuse for oppression of any government project.
Mandatory life without parole has the advantage that you CAN bring somebody back if it turns out they were innocent. It's really hard to do that once they're dead. Also: It's cheaper, since you don't get as many appeals. And you don't get so many innocents plea-barganing themselves into long jail terms rather than risk death for a crime they didn't commit but can't prove it.
The WW II connection is that IBM turned over its manufacturing plants to the government to make war materiel at a 1% profit. Carbines, gun sights, small cannons, other things, were all made in IBM's plants in Poughkeepsie, Endicott, and elsehwere.
Not just IBM, either. You'll find M1s made by fGM and Rockola, as well.
Mechanical computers (which is what much of the mechanism of a gun, distributor, carburator, or jukebox of the era actually is), and the products that make them, are also very flexible - even if the actual products aren't easily field-reprogrammable.
GM, for instance, made M1s at Saginaw Steering Gear. (Seems the machine for drilling a hole down the center of the steering shaft for the horn wire is REALLY good at making rifle barrels. B-) )
The same tools that beat swords into plowshares can beat plowshares into swords.
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What about living directly under a ~40kV power line?
I'd be more concerned with the electric field than the magnetic. And I'd be more concerned with ozone and ions from the coronoa discharge than with the electric field. But I wouldn't be very concerned about any of 'em.
There were some studies purporting to show problems. But one set turned out to be using faked data. Others neglected to account for the fact that living near substations or highlines is strongly correlated with lower income - which has LOTS of powerful nasty effects on health.
Even if there was an effect on cancer rate, I'd be more inclied to look for PCB exposure from leaking transformers or another chemical problem than some electrical phenomenon. Your body fluids are very conductive, which keeps the E-field low internally. And changing your orientation with respect to the earth's field as you walk around creates more delta-H than you're likely to get from power transmission equipment, unless you like to use distribution transformers for jungle-jims.
But if you DO live under a high-line, you might want to get an 8-foot fluorescent tube and wave it around in the yard. E-field under those, from end to end of a long tube, is often enough to ionize the mercury vapor and make it light up.
If it works, put a few of 'em in protective plastic covers (to avoid breakage) and plant them around your house for yard lights. B-) (The power company might accuse you of stealing their power. But a judge has already told 'em that if they can't keep it in their lines it's their tough luck when sombody salvages a bit of it.)
It is not a static magnetic field. A 60 Hz magnetic field is also a 60 Hz electric field. The radiation field from a dipole drops of with the inverse of distance squared. The intensity drops off with the fourth power.
It has been a few years since I studied this material. Please let me know if I am in error.
I believe you are. It's quadripole fields that fall off with inverse fourth.
Dipole fields fall off with the inverse cube, as I recall. Inverse square for the individual poles, pluse an extra inverse first-power for the separation between the poles. (Quadripole fields get an extra inverse first-power for the separation for their component dipoles in the other dimension.)
Let's assume for now that the leakage from the motor is mostly a dipole field. (CAN'T be a monopole. B-) ) For a DC field, or the "near field" of an AC field, the dipole field dominates - and it falls off inverse cube. Get two inches from the shaver and the field is 1/8th what it was at one inch. Four inches makes it 1/64th, and so on. Falls off REALLY fast with distance.
As you get farther out the changing magnetic field creates a changing electric field that in turn supports the changing magnetic field (as long as they're both propagating at lightspeed). Then you have an electromagnetic wave, detached from its launcher. This falls off with inverse square.
Under a quarter wavelength the near-field is so dominant you can pretty much ignore the far-field. Over a wavelenghth or so away the situation is reversed (unless your driving element is large compared to a quarter wavelength).
So what's the wavelength of 60 HZ? About three thousand miles.
I don't think we need to worry about the far field. B-)
So figure inverse cube falloff - or faster if the motor's magnetic leakage has more than two poles.
(This is why you need to get REALLY CLOSE to a magnet to erase your credit cards.)
Back in the '60s or so, Irv Hoff (who later was instrumental in developing ham packet radio) was a radioteletype ham. 110-bps ASCII was around and in heavy use for landline teletype and those new-fangled minicomputers. But hams were still limited to 60-bps Baudot (5-bit) teletype and obsolete machines. (This was apparently because the FCC didn't have the budget for buying new moniitoring equipment, so it wouldn't legalize the new coding scheme and speed.)
Irv wanted to go faster. Morse wasn't speed-limited and FSK modulation was allowed. So he built a couple copies of a device to convert ASCII to and from morse and send it either at 110 baud or (using tape) some truly hysterical speed.
Of course the FCC heard the high-speed signals that they couldn't translate and came after him. And he said "But they're just morse! Tape them and slow them down and you'll hear it."
So the FCC did. And shortly threw in the towel and legalized 110-baud ASCII.
Which was the whole point of the exercise. B-)
Now I think Irv may have came up with some arbitrary codings for the ASCII symbols that weren't part of Morse during that exercise. If so, and if they were easy for humans to use, it might have made sense to standardize those.
That would be "mayday mayday mayday [destination call sign] [your call sign] [emergency description] [action taken] [position of vehicle] [other information]" (for aircraft at least).
Essentially the same for boats, if life is at risk.
Lower levels are much the same but with "mayday" replaced by:
- "pon pon" ("pahn pahn") for less immediate problems (i.e. slowly taking on water, bilge pump out, can probably make port, but could somebody be ready to help out?) or
- "security" ("see-cure-ih-TAY" - all three signals come from French) for problems (i.e. hazards to navigation) that don't require assistance but should be watched for.
How dare they compare the Scum of the RIAA to such upstanding citizens. Such as: Al Capone, Tony Montana, and Don Corleone
Why not? The "content" industry has had major mob ties since it arose from the jukebox protection rackets.
this thing would be more painful to work on chip to chip communications since you don't know if the other chip is Z or the logic state you are receiving simply corresponded with your current driving logic state. (I suppose one can always send a enable / disable signal similar to DQS along with a dataline to indicated if it's active)
You have two misconceptions about the scheme in question:
1) There is no "Z" state. Both sides are ALWAYS driving.
2) You don't have to stop driving the line to receive what the other side is driving toward you.
This is essentially the same hack that lets a telephone send energy at the same band of frequencies in both directions simultaneously, on a single pair of wires:
- You terminate the line at, or near, its characteristic impedence, and so does the device at the far end.
- You inject a current into the line/terminator junction (or, equivalently, shift the voltage at the "cold" end of the terminating resistor) to send.
- You compare the voltage on the pin (or current through the pin, or current through the terminating resistor) to what you expected to see if the far end was at a no-current-injected (or terminator "cold" end at ground) state. The difference is the signal being injected at the far end.
The wire is being driven at both ends at all times (no Zs). You can always tell what the far end is sending, regardless of what you're sending.
If you chose to send by injecting a voltage at the "cold" end of the terminator, you dissipate no power when both ends are sending the same value. You dissipate a significant amount when both ends are sending opposite signals. But you also dissipate the same amount if the transmitting ends of two separate wires are switched - for the time it takes the signal to propagate and the reflection to come back. If the separation between the transmitter and receiver is more than half the length of a bit time, the quiescent state has both sides driving the same value, and the two ends drive opposite about as often as same, it's a wash.
the concept is indeed pretty cool, though you'll need some tough lil drivers that can handle incoming voltage swings while it's driving.
No you don't. You already need to drive a line that's got a charge on it from the stuff you previously drove onto it. This doesn't change that. The local end just sees the far end as being terminated by a resistor to a voltage that is either low or high, rather than being terminated by a resistor to a constant voltage.
Driving both ways simultaneously, though, is very cute.
The downside is the need to daisy-chain. That means you're driving multiple lines at 3.6 Gbps on EVERY chip, ALL THE TIME. That's a LOT of power. Even if you interrupt the daisy chain at the selected chip (and arrange things so that the quiescent states of the transmitters at both ends of an idle line match) it's still a lot of power unless you localize most of your memory access to the closest chip.
1 ... b (1): a government in which supreme power resides in a body of citizens entitled to vote and is exercised by elected officers and representatives responsible to them and governing according to law
This is the definition applicable to this subthread, where it is the institutional structure of the government that is being discussed.
In such a context it is the definition of the technical term, rather than other common uses of the same word, that matters.
I agree with what you say, but that's exactly where the article is lacking - even if this technology could be made production-ready in the next few years, it still won't make homes run stand-alone because the other technologies you mention aren't really consumer-friendly (doesn't mean they don't exist, or that some people don't use them of course).
I completely fail to understand your point.
Batteries for local storage, combined with power sources whose available power doesn't match the load curve, is ancient stuff. Virtually EVERY off-grid home power system uses them. They've been around since patent windmills were first combined with generators - before rural electrification. The only major changes to the technology in the last decades are semiconductors making inverters cheap enough that standard AC appliances become cost-effective and the unified inverter/charge controller (which is just a convenience). Consumer off-grid systems are comon enough to keep the innovations coming, the bugs shaken out, and the industry operating at a reasonable economy-of-scale.
With constant but below-peak-load sources (like water), the batteries only capture unused power in excess of demand to cover later beyond-generation peak loads. Ditto if the supply is somewhat controllable but with a limit below peak load (i.e. fuel-thermopile, start/stop engine/generator, dam/valve/turbine water).
With inherently intermittent sources (like solar or wind) they perform the same function, but have the additional feature of filling in the dips and disappearances of the variable power source.
You can plug in any energy supply and get the same sort of results. (A kilowatt reformer/fuel cell combo is just a variant on a dam/valve/turbine, where you use the batteries to cover peaks beyond your capability and sudden surges, and throttle back the generation to save the resource for later when your batteries are full and your load is less than generation capacity.)
So the availibility of reasonaby efficient, moderately low maintainence, peaking storage is a given, and the generation system can be examined in isolation (except for taking into account the cost and efficiency of available storage/peaking systems when examining the cost of the device and its operation).
Yes, it would be nice to have a more-efficient, potentially lower maintainence, storage system (such as superflywheels.) And the generation system's own physics may present additional opportunities for storage (such as hydrogen storage between the reformer and the fuel cell). But that doesn't mean you need to come up with a new, unique, invention to deal with peaking for each generation approach.
As a practical measure I'm sure the researchers know that running on 1KW per day isn't practical - they live in MN like me, so at this time of year homes will have a 0.8KW blower motor running for much of the day to keep the house warm! And during the summer you can add an air conditioner to that
So that just means you'll need a larger model, or more than one of the standard size (if manufacturers only build a small number of sizes, and you stick with forced-air).
But I doubt that there is anything magic about that 1kw exemplar that would make it difficult or more expensive to produce other sizes. Seems to me that they're just describing it in terms of a typical instalation size, for an "average" home's electric power usage.
From the article: "The cell could produce 1 kilowatt of power, nearly enough for an average home."
) turns up numbers showing that an iron takes about 1.2KW, or just over 1KW for a toaster.
A bit of googling (http://www.arctic-cat.com/generators/wattage.asp
And do you run your iron or toaster 24/7? I doubt it. (For starters, that's like running a large electric space heater 24/7.)
A typical home runs roughly a KW average - 24 KWhr/day.
So almost enough for an average home, so long as I wander round the house turning off everything else before flattening my shirt or browning some wheat. That's handy.
And that's not the way you'd do it. You'd run the reformer/fuel cell to generate power to keep your batteries charged.
- When you're pulling over a KW, all the power from the fuel cell goes straight through the inverter to run your house, avoiding the losses of a charge/discharge cycle, while the batteries (or superflywheel if they ever become practical) provide the surplus.
- When you're pulling less, the fuel cell's surplus goes to recharge the peaking batteries (or spin up the flywheel). As they approach full charge, the fuel cell starts cutting back production.
An alternative would be to use an oversize fuel cell and store the hydrogen. But that would increase the fuel cell losses - which are probably worse than storage battery charge/discharge losses - and the larger fuel cell would also be more expensive. Battery peaking is probably better for both total system and per/KWhr operating cost than an oversize fuel cell and a hydrogen storage system.
Is this better/more efficient... than an ethanol powered engine?
Yes. (Though not for the reasons given by the other postings.)
Burning a fuel in a heat engine gives you, at the absolute best, slightly less than the carnot-cycle efficiency applied to the temperature difference between the flame and the ambient temperature.
Essentially all the energy from the chemical reaction goes into heating the working fluid (which, in an internal-combustion engine is the air and fuel mixture itself - pretty efficient compared to some alternatives, though there's a lot of nitrogen along for the ride and that limits the temperature). But only about a third, max, of the energy of that excess heat is converted into useful work by the heat engine, while the rest just heats the engine and its surroundings.
A fuel cell, on the other hand, can potentially extract essentially ALL of the energy of the chemical reaction as electricity. (Some still comes out as heat. But it does a LOT better than a heat engine.)
A combustion engine gets to use all the heat of burning both the hydrogen and the carbon to oxides, minus the heat necessary to break the hydrocarbon into free hydrogen and carbon (and the oxygen molecules into free oxygen).
The reformer loses some of the energy of burning the carbon and uses some of it to free the hydrogen from the carbon and deliver it as more losely bound H2. Then the fuel cell delivers the energy of burning H and O to H20, less the energy of breaking up the H2 and O2 into free H and O, and less some efficiency losses.
Virtually ALL the energy in burning a hydrocarbon comes from burning the hydrogen, so losing part of the energy of burning the carbon (in the reformer/fuel cell case) is spilling a few drops from the bucket. Losing all but the carnot cycle portion of both the carbon and hydrogen's contribution (in the heat engine case) is dumping over 2/3s of the bucket.
What you say cannot be done legally.
Thanks. But I'll let the FSF's lawyers worry about that.
"MS is alleged to have a record of stealing other people stuff."
Never heard of them stealing source code. And this isn't all source anyway.
Starting with DrDOS, if not earlier. People have claimed that MS engages in contracts with other companies (many instnaces), then pulls stunts that amount to contract violation, in such a way that MS ends up with the other company's IP while the other company ends up dead or wounded and with no significant benefit.
I have heard this claim about several companies.
The idea of putting multiple scripts into a singe file is useful, and it's been done.
.zip, .tar, etc?
But that's not what they're patenting (or at least not what the previous poster is describing).
The idea is not to tar up files. The idea is to have a set of scripts in multiple languages in one file, along with associated metadata, so the metadata interpreter can automatically select one that one of its associated interpreters understands, allowing automatic execution of a version of the script if any version is executable on the local environment.
Are you saying there is something patent worthy about using XML instead of HTML,
I'm making NO claims about its patentability. I'm just pointing out that zip, tar, etc. are NOT prior art for the claim described above.
in other words, using XML to keep several languages' versions of one script.
I don't really see the point.
It lets authors write a script that will work if the target machine has ANY of the script interpreters available.
Yes, it's useful. What if there are only five interpretrs out there that can do the job, and ALL of them are proprietary? Nearly everybody's browser has at least ONE of them. But even the most popular interpreter is only available on a third of the people's browsers. Pick a single language, only a third (or less) of your potential audience can use the app.
So do you pick VBScript? Or Python? Or Perl? Or do you do one for EACH, bundle them up, and let each user's browser pick an interpreter?
Now you CAN hack it by including all the scripts and trusting the browser to ignore whever it can't understand. But then if it understands more than one of the languages it runs the script more than once. Oops!
This provides a formalism for telling the browser that this SET of scripts all do the same thing, so it should pick and run just one of them.
Of course to make this useful it will have to be adopted more generally. Which might push Microsoft into making it available free, and encouraging its adoption.
There are plenty of extremely portable languages, and what happens if the versions in the XML file fall out of synch?
It breaks.
What happens if you modify a script and induce a bug? Ditto. So what?
(Of course this also creates another way for companies to write tools that produce code that runs correctly on their own browser products and screws up on those of others. B-) )
I'm really fascinated about, if this turns out to not be a lie, the long-term ramifications of this. It's a can of worms that you can't undo.
Even if THIS one is NOT true, it's only a matter of time before there's a REAL leak of the REAL code.
I'm surprised they've kept it under wraps as long as they have.
I doubt that Microsoft intentionally planted this snare but if any future open source project even vaguely resembles this leaked code I have no doubt that Microsoft will open their full arsenal of lawyers.
On the flip side:
A comparison of the code against that of open source projects could be used to detect places where MS developers have included open source code in MS products. With this as a starting point, a suit's discovery process could bring it out in a form that could be used as evidence against MS.
(Of course the leaked code should be analyzed by a consulting organization separate from the open source developers, to keep developers and their servers clean for defense against later claims from MS.)
MS is alleged to have a record of stealing other people stuff. Will be interesting to see if it's true, provable, and something can be done as a result.
I'm surprised nobody has sent them patches to fix security issues yet.
I'm not. (Though I WON'T be surprised if somebody sends 'em a patch anonymously. B-) )
Anybody who sends a fix in a tracable way - and lets the rest of us know they did it - is likely to be sued, or prosecuted, for having a copy of the source. So why risk it?
Not even LEDs are 100% efficient. However, for an optical system, the heat production is related to the duty cycle of the lamps, rather than the switching speed, so the heat production should remain constant regardless of clock speed.
That's true of the heat production in the guts of the lamp itself (at a given light intensity). But there are other factors.
On the one hand, this means you don't need to improve cooling to overclock. On the other, it means that you can't improve the overclock level with improved cooling.
Most of the heat loss in a circuit comes from the I-squared-R losses of the currents needed to charge and discharge the stray capacatance of the wiring (even the tiny traces on the ICs) and the space-charge of the devices.
In particular, if the wire has any significant length, you need to run that current through a series resistance (at least at the driving end) matching the impedence of the wire, in order to produce a nice waveshape at the far end and prevent "ringing" as the signal bounces back-and-forth (which would degrade the waveshape at the inputs to far-end gates and make the signal both more sensitive to noise AND more generative of noise to interfere with its neighbors.)
With CMOS you only pull power (except leakage power) when you CHANGE the state of a signal. But when you do, you have to charge, or discharge, the signal wiring through that matched resistance. The impedence of the wiring doesn't change a lot with technology and speed. So with a given length of wire, you have a given amount of energy dropped every time you switch it. Switch it twice as fast, generate twice as many pulses of heat.
New generations of semiconductors fight this in three ways:
- Shrink the components (so they have less stray capacatance to charge and discharge).
- Shorten the signal runs by making the components smaller so they can be closer together (reducing the stray capacatance of the lines). (But this doesn't help for signals that HAVE to cross the chip, or leave it.)
- Lower the power supply voltage (so you don't have to swing it as far. Current goes up with the the voltage, heat loss with the square of the current.) (For signals that leave the chip this may be harder to do than for signals that stay on it - due to external interference.)
For switching a light-emitting device you still have to charge and discharge the capacatance of the device itself and the wiring to it. Switch it faster and IT doesn't heat up much more. But the driver circuit does.
By putting a light modulator on the chip, Intel's new technology wins in two ways:
- You don't have to rapidly switch the power to the laser (which involves switching a LOT of current through an impedence-matching resistor).
- You don't have to run a microwave-speed signal through a long resistive wire, which degrades its waveshape and also produces still more losses.
Instead you switch a low-power, short-range, on-chip wire to a low-capacatance active region on the on-chip modulator. Switching losses are relatively small, comparable to those of a gate-to-gate internal signal in the same chip.
Airlines do not need fat pipes.
Yes, but this is a service of the airPORT, not the airLINES. What pipes does the port itself have?
But let's assume, for the moment, that the airport's own feed is either inadequate or unsuitable for sharing (i.e. airline safety issues). OK, you need to install a new feed.
Let's make it a really fat feed. Let's say that it's SO fat that it costs TEN THOUSAND DOLLARS per MONTH - or just enough less that adding in maintainence on the hotspots brings it to that.
For SFO that works out to under THREE TENTHS OF ONE CENT per passenger-trip.
Again, I doubt anyone will feel a pinch.
There are at least two ways the airport can pay for this. One is to include it in the fees charged to the airlines: landing fees, rental of hangar and counter space, various other services. Another is to include it in the rent paid by shops and restaurants.
But do you have any idea how CHEAP this would be in an airport environment, if it's NOT being metered?
Figure a couple dozen wireless routers (at $100 each). An fat pipe internet feed (which they probably already HAVE, and can piggy-back on for essentially free if they give the hotspots a lower priority), a bit of cat-5 strung through the ceilings, a couple of hubs, and a port on the router (which they ALSO already have). Call it a one-time investment of a few grand. (Costs more for labor to install it than to buy the parts.)
Recurring costs of less than a grand a month or so for maintainence. Call it two grand if you're actually PAYING for the bandwidth. Power for the machines is below the noise.
HOW many passenger-trips through a major airport in a month? (SFO was 41 million per year in 2000, almost three and a half MILLION per month. $2*(10**3) / 3*(10**6) = $0.000666... seven ONE HUNDREDTHS of ONE CENT per passenger-trip.
Somehow I don't think anybody will feel the pinch.
It makes sense because the incremental cost of providing the service is probably lower than the cost of the soap (lots in my flight bag) and the capital is less than the cleaning budget for the toilets for a day or two.
It also makes sense because providing the internet feed is dirt cheap, while trying to meter it and collect fees is NOT.
It's called a "marginal service" - like the shaver outlet in the bathroom (without a meter and coin slot), providing lighting (rather than requiring you to bring your own flashlight), or the free elevators (without a ticket taker). It's MUCH easer and cheaper to include the cost of the service in the overhead cost of the environment (and the goods and services you buy there) than to try to bill for it specifically.
Closer to the shaver outlet than the elevator, by the way. Unmetered internet service is dirt cheap to provide. Installing and maintaining elevators is DARNED expensive.
Because every so-called communist government has in practice been an Oligarchy. Contrary to American knee-jerk anti-communist propaganda there are no commies and never will be.
Yeah, we've heard that all before.
Real communism hasn't been tried yet. The people calling themselves communists are actually x.
Real socialism hasn't been tried yet. The people calling themselves socialists are really y.
Real capitalism hasn't been tried yet. The people calling themselves capitalists are really z.
Real Christianity hasn't been tried yet.
Real Islam hasn't been tried yet.
and on, and on, and on.
I could care less about what a system is SUPPOSED to be IN THEORY, if only people would do what the theory says. Some people will always be selfish, corruptable, and/or prone to ideological confusion. And you're not going to change that - at least not for several lifetimes (after which there's the question of whether it even matters, since what you're dealing with is no longer human beings). So the HOLES in the theory, and the ways it can be subverted, are all part of the system.
From my standpoint, real FOO is what you get when you try to implement system FOO with real people.
This sounds like a civilian version of the GPS/lidar/etc/binoculars recently used by the military for spotting targets for artillery and other attack missions.
Look at the target, center the crosshairs, read the *target's* GPS co-ordinates (or dump them into the battle net).
Every time science comes up with a new form of evidence (or even a new way of analysing old techniques), someone gets convicted because of a persuasive argument which blinds the jury with science.
It's happened with DNA, fingerprints, computer cracking.... Hopefully the technology is eventually ironed out such that this stops happening.]
Meantime, this is cold comfort to victims of such miscarriages of justice, or their families.
But it's two edged:
DNA evidence is now being used to clear people who have spent decades in prison for crimes they didn't commit.
At least if you have the death penalty the vctim of the miscarriage of justice (eventually) isn't in too much of a position to care.
And it puts them beyond reach of ANY correction, when technology advances to the point where it can discover and prove their innocence, winning them release (and millions in restitution for the false imprisonment).
See The Innocence Project for more.
I, at least, am totally opposed to the death penalty. Not because the crooks don't deserve it - most of 'em do. But because it's administered by a government, with at least the usual levels of incompetence, corruption, and misuse for oppression of any government project.
Mandatory life without parole has the advantage that you CAN bring somebody back if it turns out they were innocent. It's really hard to do that once they're dead. Also: It's cheaper, since you don't get as many appeals. And you don't get so many innocents plea-barganing themselves into long jail terms rather than risk death for a crime they didn't commit but can't prove it.
The WW II connection is that IBM turned over its manufacturing plants to the government to make war materiel at a 1% profit. Carbines, gun sights, small cannons, other things, were all made in IBM's plants in Poughkeepsie, Endicott, and elsehwere.
Not just IBM, either. You'll find M1s made by fGM and Rockola, as well.
Mechanical computers (which is what much of the mechanism of a gun, distributor, carburator, or jukebox of the era actually is), and the products that make them, are also very flexible - even if the actual products aren't easily field-reprogrammable.
GM, for instance, made M1s at Saginaw Steering Gear. (Seems the machine for drilling a hole down the center of the steering shaft for the horn wire is REALLY good at making rifle barrels. B-) )
The same tools that beat swords into plowshares can beat plowshares into swords.