My brother has been an electrical engineer for the local power company for 22 yrs now. His explanation:
Underground lines cost more initially.
Most of the lines installed 10-20 years ago, with expected lifetimes of 30+ years, are prematurely failing. The unanticipated cost to the utilities, several hundred million dollars. That makes them pause and think a bit.
The utility has to add bunches of power-factor compensators (basically big inductors) to counteract all the capacitance of all that buried cable. That takes space ($$$ and time to acquire) and $$$, and ongoing checking and maintenance.
> E.g., how _do_ you know that skin effect can't possibly apply? Skin effect is what happens at high frequencies. Lightning is one extremely brief pulse of electricity. Depending on the wave shape and duration it could have a metric buttload of high frequency components.
Wrongo, Bub. Lightning is DC pulses, averaging around 330 milliseconds in length (http://nis-www.lanl.gov/nis-projects/forte_scienc e/html/LA-UR-03-5909/ratemap.pdf)
The only RF is at the leading and trailing edges. If you assume 1 one microsecond rise time, that's RF for less than 1/300,000 of the pulse length. An insignificant amount of RF.
Then there's the "skin effect" business. Balderdash, for several reasons.
(1) Skin effect happens where there is an abrupt change in resistivity, which doesnt happen in the human body.
(2)Your skin is very HIGH resistivity (try it with an ohmmeter).
(3)The layer just below the skin is mostly a fat layer. Fat is also high in resistivity.
(4) You don't get really low resistivity until you get quite a bit below the skin and fat layers.
(5)
If skin effect did happen in humans, then 70 years of RF heating treatments (diathermy) would have been impossible.
So there's darn little RF, less than 300 parts per million, compared to DC, and even if there were lots of RF (which there isnt), the human bnody is just about the perfect composition to avoid any skin effect.
Now onto the "burnt points". There's a very simple explanation for this. The body core is a very good conductor of electricity, with LOW voltage drop, so the heating effect, "burns", doesnt happen INSIDE the body. Lots of amps, but very little voltage drop. Remember W = I^2R?. But at the entry and exit points you have high-resistance skin and fat, not to mention medium resistance ionized air. There you have both lots of I^2 and lots of R, so you get lots of Watts, and lots of heating, ergo Burn City, Arizona.
So I see no case whatsoever for any phenomenon like "flashover", especially as elucidated by medical doctors, apparently without a smidgen of basic comprehension re Ohm's Law.
Just because some ourdoorsy site says something doesnt prove it is true. One might suspect just by probablility and the geometry of the situation that the majority of "lightning strikes", maybe up to 95%, are not direct hits on people, but rather lightning surges conducted through the ground from a nearby strike. If you've ever seen what lightning does to a large tree, you might wonder how anybody survives a direct strike. They probably don't. But there are thousands of "close call" survivors that certainly got enough of a jolt to thinnk they got a direct hit.
There is a term called "flashover". There are also terms like "leprechauns", "ghosts", "lucky gum", "win an ipod by punching the monkey".
Lightning strikes are complex phenomena. You've got electricity, ions, conductors, semi-conductors, resistances, and insulators, all in a complex configuration. There are gonna be "funny" effects.
All it takes is a miniscule percent of the lightning strike to burn off your clothes. If that is "flashover", one has a really long row to hoe to prove that adding or subtracting a few inches of plastic and metal is going to make any discernible difference either way.
You could just as well argue that a vaporizing cell-phone is going to make the air path to ground more conductive, bleeding away some of the current that would go through the body. There's no way to prove this either way by having 10,000 doctors hand-waving.
So IMHO, this is an unproven and probably unprovable concern over a miniscule problem, unsettleable either way, and trivial in comparison with the effects of lightning.
There is no such thing as "flashover". The human body is largely salty water, an excellent conductor. There is nothing about the "surface" of the body that makes it a better path for conduction.
Even if the surface were a better path for "flashover", that would be a very bad thing. That would concentrate the energy into the top layers, probably vaporizing off your skin. You need your skin.
Maybe somebody read something about "skin effect", a real electrical phenomenon, but inapplicable to this case.
If you get struck by lightning, you have much worse things to fret over than the exact path lightning took.
During WW2, the British protected their island with various fighter planes, many powered by an internal-combustion engine called "the Merlin". (Incidentally, it wasnt named after the magician).
The Merlin engine had been under intensive development for several years, eventually, due to improvements in carburation, supercharging, and internal strength, going from under 1,000 HP to over 2000 HP.
But it's specific fuel consumption didnt improve much if at all.
Now it's hard to imagine a strong enough conspiracy, when your nation is on the verge of being overrun by the Huns, to still hold down improvements in engine economy and efficiency.
Same thing happened later on to the US. Our bombers had to go over Germany without fighter escoerts, because the P-51 fighter planes, also powered by Merlins, did not have the range to stay with the bombers all the way to Germany and back.
Lots of bombers were shot down over Germany, lkosing ten US airmen per plane.
Much later, drop tanks were developed to increase their range. Note they didnt just tune up the engines, instead it took over a year to develop the drop thanks, pipes, pumps latches, and stability tests to increase the P-51's range.
Same thing could be said of Israeli tanks and planes. They were attacked many times, and they didnt drag out the 200MPG carburetors either.
I wish I could agree with you, but I think the opposite is often the case.
The less you know, the MORE you need a tool that doesnt have lots of glitches.
p>
If you're a PhD EE, then you already know all about image and harmonic and third-level intermod products. So when you see a strange blip on the radar, you go "of course, I'll ignore that, it's obviously the second harmonic of TV channel 41 minus the neighbor's baby monitor."
If you're a noob, you may end up chasing all over the neighborhood looking for what doesnt exist.
Still, I'm going to put this little item on my birthday wish-list. If only to try hitting it with a signal generator and seeing just how prevalent are the spuriosities. Hope I'm wrong.
There's these things called the laws of econoics and physics which make it unlikely to duplicate the spcs of a $4000 specrum analyzer for $100.
Now Idon't know exactly what they put in that little USB pod, but it's unlikely it has the expensive dual-conversion superheterodyne signal chain, the interdigital varactor tunable filters, the low-noise Gallium-arsenide preamps, and the other expensive features of a real spectrum analyzer.
These cheap ones *may* be *mildly* useful, under *some* conditions, at *some* temperatures, and in *some* environmnts*. But usually the times we really need one of these eexpensive beasties is when all the conditions are unsuitable for the cheapo ones.
For example, just leaving out the tricky filters means the cheapo device will be very sensitive to other, out of band signals, that are of no consequence. False positives, very bad thing to see when you're trying to impress the client. Even worse when they pay big bucks to relocate the interfering devices, and the network still doesnt work.
Here's a rather large quibble-- since when are CCD's "retroreflective"?
Retroreflective means the surface reflects light back to the source. Stop Signs, taillights, and some fire hydrants are retroreflective. So are to a lesser extent, disco-balls, diamonds, and ball-bearings. But CCD sensors? Why? And since when? I've never seen one behave that way. And in a photosensor you want one that COLLECTS and absorbs light, not reflects it or even worse, retroreflects it.
Now at some angles, CCD sensors are going to show a diffraction pattern, due to the spacing of the sensor elements, but only if they're out in the open, without a lens. Are these "Reasearchers" seeing this effect?
This article sure sounds like high-grade snake-oil!
This isnt a real brain-teaser for those that might want to photograph whatever they want:
The first person that gets accidentally zapped in their eye will sue for $100,000,000. That will stop this technology right there.
Even easier, just mention the above scenario to a corporate lawyer or legislator-- whammo, you don't even need one painful example.
Put your camera behind a little piece of burlap, cheesecloth, grille-cloth, or similar material. The camera will be able to see out, with maybe a f-stop or two of degradation. The super-anti-spying sensor will not see a thing.
Go to 7-11 and buy a pair of $3.99 cheap mirrored sunglasses. Put the sunglasses over the camera lens. The soooper sensor will see a mirror. Camera will see the world just fine, a f-stop or three dimmer but no sweat.
Go buy a square yard of reflective window-tint material. Cut it into 1 inch square pieces. Sell them ion eBay as "Miracle anti-sbnooping technology" for $4.99. $$Profit$$$!!
If you read the fine article, they just happen to mention in passing that the stuff only stays in that special state when squezzed to aboout 8.8 million PSI.
*Lots* of elements have interesting properties at that kind of pressure. IIRC Water changes into a different crystalline structure, Ammonia acts like a metal. Problem is, most of these states are unstable. You can't hold a chunk of Ice-X or Metallic Ammonia, not unless you're somewhere near the core of Jupiter. We're talking pressures in the GigaPascal range, not something you can do at home with a good pair of pliers.
Ah, this development is a good thing for those that have problems with the "conduction" part of the heart, i.e. the "wires". But in many cases it's not the wires that have gone bad, but the actual signal sources, special cells that generate the 60 millivolt pulses. Or those cells may be fine, but they've lost their connection to the nerves that control the heaart rate.
In all these cases, you need an electrical pacemaker-- adding conductions cells is unlikely to do anything.
>The boys measured what they needed given the context. It is after all, the power pulled from the wall socket that matters and things like conversion efficiency in the power supplies or radiation loss from the components is merely academic.
I didnt say a word about those bogus points, you did.
Meanwhile, did you know that a 10% reduction in line voltage corresponds to a modest reduction in lumen output from an incandescent bulb yet extends the life of said bulb by a factor of 5.
Yes. But that has nothing to do with this thread.
That's enegry savings in addition to a 5X savings in light bulbs!
Um, no. Light bulbs are LESS efficient at lower voltages. More of the power goes into heat and less into making usable light.
Real money buddy!
Yep, real money lost. If you want to save money, buy flourescent bulbs.
Or to feed it to ya in more understandable terms; given the number of light bulbs in the average American household, that works out to an extra bag of weed every year!!!
Try less weed, more critical thinking. Works for me.
And no need to rewire your house either. Just buy bulbs rated at 130VAC instead of 120VAC.
Or, put an appropriately sized diode in series with the bulb and up the wattage as desired. Don't worry, you can do the math. Just do that part before you bake.
The power company uses an analog computer, an mechanical integrating multiplying device, invented around 1888. Basically it's a two coil electric motor. One coil goes ACROSS the line, measuring the volts. The other coil goes in series with the line, measuring instantaneous amps. The magnetic torque is the instantaneous product of the two magnetic fields, so the meter measures true watts.
Um, No.
PFC power supplies are about 20% more expensive to build. I havent seen a single PFC power supply (in the USA) out of dozens I've opened up. You can identify them in a jiffy-- they don't have the big capacitors by the power input, they're on the other side of the transformer, and considerably larger than usual.
> When the voltage peaks, the current peaks - the two are in phase.
Which doesnt help when trying to measure watts. The volts and amps are in phase, BUT in order to supply power when the sine wave is near zero, the current draw is non-linear. i.e. the current doesnt drop as much as expected as the voltage drops. Which again fools inexpensive wattmeters.
Oh, the humanity. When a armchair EE like me can poke all these holes, what's to become of us?
Measuring power is, as the cold fusion guys figured out, is a lot harder than it seems.
They didnt as far as I could see, mention exactly what equipment they used to measure the power draw of these fine devices.
If you think, like most people, that electrical power is amps times volts, BRAAAP, you're the weakest link.
Power is the integral of instantaneous amps times instananeous volts. You can't use a $2.99 Harbor-Freight voltmeter and ammeter to do this.
All modern power supplies use a rectifier and switching regulator arrangement, which unlike an old steam iron, does not draw amps in proportion to volts. Instead it has a very non-linear power curve, full of sudden peaks and drops, and even some reverse current flowing during every AC cycle!
The numbers they published are very suspicious-- only ONE significant digit in the lower numbers, which suggests either they rounded them off without telling us, or they used a wattmeter without a low power range.
Either possibility introuduces anywhere from 25% (by dropping a digit) to 600% (trying to read 2 watts on a 200-watt meter) of error.
Even if these boxes draw that much power, it's not necessarily a waste. A lot of folks live in houses that require heating during at least part of the year. Every watt of heat from one of these boxes is one less watt of heat the house heating system will have to produce (assuming there's a thermostat involved).
On the other hand, if you have air-conditioning in use, each watt of heat from these boxes will require an additional 1/EER watt of power from the AC unit. EER's nowadays tend to be in the range of 10 to 14, so that's an extra 7 to 10 percent extra power draw during the hot months.
All these devices require a TV or monitor, IIRC. Those draw considerable power too, often dwarfing the gaming box's power.
So guys, why do such a half-arsed job of it? Why not be the best?
Microsoft announces delay in delivering "Bill Gates 2.0"
Microsoft is distressed to announce a delay in the previously announced (2 years ago) upcoming delivery of "Bill Gates 2.0". The original announcement was meant in good faith, but many issues have intervened to delay the roll-out of Bill Gates 2.0:
He got stuck in the "Vista bugs at rollout" meeting for an unexpected 78 days, one bullet point per minute.
He really wanted to explain why the string print int 21h call was NOT stolen from CP/M, even though it copies the ending "$" semantics. He spent most of last summer on this with no plausible results.
The bulldozers took longer than expected to clear away the mountain of shareholder bodies coveriong the Redmond campus, after their ill-fated "Last chance rally to change his mind".
As a last thing he wanted to fix up MSDOS 5.0 so it would actually be usable.
Spent most of each day working out, even though turned down for "Survivor 2003, 2004, 2005, 2006, 2007...".
Most of the designers of the current stockpile of bombs have retired and/or died.
The new guys have been twiddling their thumbs for 20 years now, just designing bombs on paper (CRT's more likely). And cleaning up their predecessors FORTRAN programs. And running simulation after simulation.
They've never had the opportunity to actually test any of these designs.
Not underground, and certainly not above-ground where everybody can enjoy it.
And these NEW, "better" designs are not going to be tested either.
Never mind that simulations can't simulate what we can't forsee.
Plenty of things were not foreseen in the last generation of bombs-- the effects of corrosion for one.
These new bombs are not going to reduce the amount of plutonium in the world, just move it from warhead bunkers to storage bunkers. There isnt a single reactor built or planned that can burn all the excess plutonium, so the net amount of it will not decrease. Just a bigger risk of it getting hijacked when in transit. Not a big improvement IMHO.
Excuse me if I'm cynical, but couldnt this just be another way of keeping the bomb-builders employed and busy? Isnt there something more useful they could be doing, like fusion research?
If these doohickeys have pores that are so small, how prone are they to clogging? Lots of things work just fine in the clean laboratory but dang it, just don't work in the real world, where there is rumored to be dust. It sounds like these things could get clogged by anything bigger than a few water molecules, which includes an awful lot of things out there.
Nobody already does use it:
World steel production: About 1,300,000,000 tons.
World titanium metal : About 0,000,072,000 tons.
That's about 0.0055%. 55 parts per million. And a lot of that titanium goes into alloying steel!
World use of titanium as a structural metal is miniscule.
Um, no. These guys should have talked to a mechanucal engineer, or metallurgist before going off on this quest for cheqaper titanium.
The cost of producing Titanium isnt even the 5th most prominent reason that it's not used more. Here's a few more significant reasons:
Steel is about $40 a ton, and can be blended and treated for a wide range of strengths, flexibility, ductility, and other desireable properties. Titanium costs 100 to 1000 times more, and isnt as versatile.
Steel and other metals can be heated up, hammered, forged, drilled, milled, scarfed, ground, chamfered, put through dies, bent, hammered, case-hardened, sputtered, peened, and plated. Over and over again. Titanium doesnt like most of those processing steps.
Most metals gladly alloy themselves with various useful elements, such as copper, molybendum, chrome, carbon, etc, to improve their strength, ductility, or springyness. Titanium doesnt.
Most metals tolerate a little variation in processing time, temperatures and rates of change. Titanium doesnt.
Most metals can tolerate being splashed with various environmental contaminants, like water, road salt, acid rain, paints, glues, waxes, etc. Titanium is so sensitive to contaminants, just *touching* a titanium bolt with a chrome or cadmium-plated wrench is enough to make the bolt very brittle! Just writing on a titanium sheet with a (horrors!) felt-tip marker is enough to embrittle the sheet.
given the choice of using steel or aluminum, versus using titanium at 100x the cost, 10x the likelyhood of the part breaking if touched by the wrong stuff, most engineers will go with anything but titanium.
The DC-10 did have some design issues with the cargo door. But two of the big crashes were NOT due to engineering errors. The engine falling off at Chicago was due to using a dang forklift to remove the engines, which cracked the support structure. The crash in Iowa was due to a rare metallurgical problem with the engine compressor disk. Neither one was an explicit engineering error.
The walkway collapse was more a case of poor design review. The original design had ONE rod supporting all the walkways. Nobody realized that there's NO WAY to build that! You can't thread a 60-foot rod through all those walkway beams, not when the building roof is in place. The multi-rod redesign was obviously not reviewed properly.
Slashdot Mirror
oops, bad math, they can hold out for 666 years based on their market value, forever if you assume they get 4% interest.
at that rate, they can only hold out for 33 years!!
Wrongo, Bub. Lightning is DC pulses, averaging around 330 milliseconds in length (http://nis-www.lanl.gov/nis-projects/forte_scienc e/html/LA-UR-03-5909/ratemap.pdf)
The only RF is at the leading and trailing edges. If you assume 1 one microsecond rise time, that's RF for less than 1/300,000 of the pulse length. An insignificant amount of RF.
Then there's the "skin effect" business. Balderdash, for several reasons.
So there's darn little RF, less than 300 parts per million, compared to DC, and even if there were lots of RF (which there isnt), the human bnody is just about the perfect composition to avoid any skin effect.
Now onto the "burnt points". There's a very simple explanation for this. The body core is a very good conductor of electricity, with LOW voltage drop, so the heating effect, "burns", doesnt happen INSIDE the body. Lots of amps, but very little voltage drop. Remember W = I^2R?. But at the entry and exit points you have high-resistance skin and fat, not to mention medium resistance ionized air. There you have both lots of I^2 and lots of R, so you get lots of Watts, and lots of heating, ergo Burn City, Arizona.
So I see no case whatsoever for any phenomenon like "flashover", especially as elucidated by medical doctors, apparently without a smidgen of basic comprehension re Ohm's Law.
So IMHO, this is an unproven and probably unprovable concern over a miniscule problem, unsettleable either way, and trivial in comparison with the effects of lightning.
Same thing could be said of Israeli tanks and planes. They were attacked many times, and they didnt drag out the 200MPG carburetors either.
So let's just retire the 200MPG stories, okay?
The less you know, the MORE you need a tool that doesnt have lots of glitches. p> If you're a PhD EE, then you already know all about image and harmonic and third-level intermod products. So when you see a strange blip on the radar, you go "of course, I'll ignore that, it's obviously the second harmonic of TV channel 41 minus the neighbor's baby monitor."
If you're a noob, you may end up chasing all over the neighborhood looking for what doesnt exist.
Still, I'm going to put this little item on my birthday wish-list. If only to try hitting it with a signal generator and seeing just how prevalent are the spuriosities. Hope I'm wrong.
Now Idon't know exactly what they put in that little USB pod, but it's unlikely it has the expensive dual-conversion superheterodyne signal chain, the interdigital varactor tunable filters, the low-noise Gallium-arsenide preamps, and the other expensive features of a real spectrum analyzer.
These cheap ones *may* be *mildly* useful, under *some* conditions, at *some* temperatures, and in *some* environmnts*. But usually the times we really need one of these eexpensive beasties is when all the conditions are unsuitable for the cheapo ones.
For example, just leaving out the tricky filters means the cheapo device will be very sensitive to other, out of band signals, that are of no consequence. False positives, very bad thing to see when you're trying to impress the client. Even worse when they pay big bucks to relocate the interfering devices, and the network still doesnt work.
Retroreflective means the surface reflects light back to the source. Stop Signs, taillights, and some fire hydrants are retroreflective. So are to a lesser extent, disco-balls, diamonds, and ball-bearings. But CCD sensors? Why? And since when? I've never seen one behave that way. And in a photosensor you want one that COLLECTS and absorbs light, not reflects it or even worse, retroreflects it.
Now at some angles, CCD sensors are going to show a diffraction pattern, due to the spacing of the sensor elements, but only if they're out in the open, without a lens. Are these "Reasearchers" seeing this effect?
This article sure sounds like high-grade snake-oil!
*Lots* of elements have interesting properties at that kind of pressure. IIRC Water changes into a different crystalline structure, Ammonia acts like a metal. Problem is, most of these states are unstable. You can't hold a chunk of Ice-X or Metallic Ammonia, not unless you're somewhere near the core of Jupiter. We're talking pressures in the GigaPascal range, not something you can do at home with a good pair of pliers.
In all these cases, you need an electrical pacemaker-- adding conductions cells is unlikely to do anything.
I didnt say a word about those bogus points, you did.
Meanwhile, did you know that a 10% reduction in line voltage corresponds to a modest reduction in lumen output from an incandescent bulb yet extends the life of said bulb by a factor of 5.
Yes. But that has nothing to do with this thread.
That's enegry savings in addition to a 5X savings in light bulbs!
Um, no. Light bulbs are LESS efficient at lower voltages. More of the power goes into heat and less into making usable light.
Real money buddy!
Yep, real money lost. If you want to save money, buy flourescent bulbs.
Or to feed it to ya in more understandable terms; given the number of light bulbs in the average American household, that works out to an extra bag of weed every year!!!
Try less weed, more critical thinking. Works for me. And no need to rewire your house either. Just buy bulbs rated at 130VAC instead of 120VAC. Or, put an appropriately sized diode in series with the bulb and up the wattage as desired. Don't worry, you can do the math. Just do that part before you bake.
The power company uses an analog computer, an mechanical integrating multiplying device, invented around 1888. Basically it's a two coil electric motor. One coil goes ACROSS the line, measuring the volts. The other coil goes in series with the line, measuring instantaneous amps. The magnetic torque is the instantaneous product of the two magnetic fields, so the meter measures true watts.
Um, No. PFC power supplies are about 20% more expensive to build. I havent seen a single PFC power supply (in the USA) out of dozens I've opened up. You can identify them in a jiffy-- they don't have the big capacitors by the power input, they're on the other side of the transformer, and considerably larger than usual.
> When the voltage peaks, the current peaks - the two are in phase.
Which doesnt help when trying to measure watts. The volts and amps are in phase, BUT in order to supply power when the sine wave is near zero, the current draw is non-linear. i.e. the current doesnt drop as much as expected as the voltage drops. Which again fools inexpensive wattmeters.
So guys, why do such a half-arsed job of it? Why not be the best?
Microsoft is distressed to announce a delay in the previously announced (2 years ago) upcoming delivery of "Bill Gates 2.0". The original announcement was meant in good faith, but many issues have intervened to delay the roll-out of Bill Gates 2.0:
Excuse me if I'm cynical, but couldnt this just be another way of keeping the bomb-builders employed and busy? Isnt there something more useful they could be doing, like fusion research?
If these doohickeys have pores that are so small, how prone are they to clogging? Lots of things work just fine in the clean laboratory but dang it, just don't work in the real world, where there is rumored to be dust. It sounds like these things could get clogged by anything bigger than a few water molecules, which includes an awful lot of things out there.
That's about 0.0055%. 55 parts per million. And a lot of that titanium goes into alloying steel! World use of titanium as a structural metal is miniscule.
The cost of producing Titanium isnt even the 5th most prominent reason that it's not used more. Here's a few more significant reasons:
given the choice of using steel or aluminum, versus using titanium at 100x the cost, 10x the likelyhood of the part breaking if touched by the wrong stuff, most engineers will go with anything but titanium.
That was meant as a (weak) "joke".