I have unfortunate first-person experience for why printers underestimate the amount of ink:
They sell more expensive ink that way.
You'll notice your typical printing regimen uses much less yellow than the other shades, so if it's a trui-color cartridge, unless you're printing a lot of "skin tones", the yellow section will tend to still be mostly full when the other ones have run out, or at least "low".
Many printers try to estimate the amount of ink used, but if you remove a print cartridge or reset the printer EROM, or the cartridge contacts get intermittent, many printers when they see a "unknown but used cartridge, assume it has unknown quantity and assume the worst.
The printers with separate print heads and ink cartridges have a serious problem-- if the printhead runs out of ink the little teeasy tiny microscopic print head resistors blow out, requiring an expensive $40 printhead. On a HP D1xx printer, there are four of these. So the printer signals "ink low" when it's really probably still 1/3 full, just to protect the printheads.
The printers with separate print heads and ink cartridges can get air-bubbles in the plumbing between ink cartridge and printhead if the ink runs low, leading to poor printing and printhead blowouts, so again they thy to err on the safe side.
The two endpoints, be they separated in time or space, get the same information all right.
But mother nature sure is devious, the information is content_free. It's as random as can be.
You can get the same quality of information by flipping a coin.
It's touching, in this age, to see someone with such firm faith. Faith, I say, because you havent provided a single verifiable fact, so it must be 100% pure unalloyed Faith.
Okay, let's go with: you're right... So for some unfathomable reason this wonderful Stirling engine with soo many benefits not to mention rumored efficiency has not made the slightest splash in the real world.
Conspiracies? CIA plot? Vooodoo?
Then again there's a cult of "scientists" that know with a small deltaT, you have a miniscule top efficiency. Been known to these cultists for centuries. On top of that loow theoretical efficiency, you impose the intrinsic inefficiencies of the Stirling Cycle, where hot and cold sections are mostly intermingled, leading to tremendous heat losses. Miniscule times teensy gives almost vanishing results. There are few Stirling engines that could even pay the interest on their original cost, even with a free source of heat.
Ergo they've been looked at every few years, then discarded by these fanatic scientists and physicists.
That's swell. However in military applications like this one they went with the Stirling as it's QUIET, not because of its efficiency (which is low). So low it's hard to find numbers. The ones in the technical peer-reviewed papers are around 3%. The ones in the glossy PDF's from places with "stirling" in their name are heavily caveated numbers around 50%. Guess which number I'd consider more reliable.
The only number in your posting is "45" (percent), and it's wrong.
Searching the InterWebs finds a NASA press release quoting 20% efficiency.
And that's with a deadly radioisotope that can supply 860C heat.
To believe Stirling cycle is superb you have to posit huge scientific industrial conspiracies, heretofore unachieved progress in bizarre materials, and quite a bit more. Lotsa luck.
>I would argue that a Stirling cycle device can claim a higher efficiency than the venerable modern gas turbine.
??? Argue all you want. A quick search of this "InterWebs" thing shows a LOT of argument about Stirlings. But you'd think after 200+ years of development there would be maybe at least just *one* working example where the efficiency was measured and usably high. Hmmm......
>When heated, the device generated sound at 120 decibels -- the level produced by a siren or a rock concert.
Well whoopee-ding.
So they get one watt of sound power.
Now how many watts of heat did it take to generate that one acoustic watt? Deponent sayeth not.
General Carnot principles suggest a whole spitload of watts.
In general converting random motion, the lowest quality of energy, into periodic sound waves, a MUCH higher quality of energy, never happens by chance or with any notable efficiency. That principle has been known for going on 175 years now.
Now feed that very expensively obtained watt into a most efficient piezoelectric microphone. Microphones rarely go above 2% efficient.
To be sure, measure the temperature drop. I suspect you'll be lucky to get one degree of drop. Out of 480.
Divide that by the heat to sound efficiency and you get a number with an amazing and uninteresting number of leading zeroes.
I'll eat several hats if the heat to electricity efficiency factor exceeds 0.001
Even a Stirling engine can do better, and even that is totally useless.
Nothing to see here. It's just a Prof that's spent $2 million on a wild goose chase. Now with the great smell of fish!
The rub is multi-fold:
Good old Carnot's law. The efficiency is limited by the temperature drop across the device compared to the absolute temperature. Now take two thermometers, stick one up your butt and fart. compute the temperature difference. Divide by 483. That's your efficiency in converting heated gas into sound. Prolly about 0.005% as a rough approx.
For a less gross example, pucker your lips and blow. Do this for five minutes or until you pass out. You probably feel warm-- that's the heat. How much acoustic power did you generate? Well a loud whistle is about 100dbA, about a hundredth of a watt. Efficiency, 0.004% at best.
Piezoelectic efficiency. Well, it's really high-- for an acoustic transducer. The Interwebs seem to reveal no figures for this, and in general a high level of coyness is a way of hiding embarrasing numbers. Let's assume a best-case number of say 40%.
The impedances. Crystals are very high impedance devices, putting out LOTS of volts at vanishingly small amps, which is bad news for us, as most of our power sinks are low impedance. Getting a few milliamps at 40KV is not very compatible with powering your laptop, which is about a million times lower in impedance. It's particularly inconcvenient converting tens of kilovolts downwards with economy and efficiency.
So sorry, probably much less than nothing to see here, just another bundle of our taxpayer's money spent on a totally pointless technical exercise.
There are a lot of caveats in any use of fuel cells:
* A lot of fuel cells work just fine in the lab. Where you have several PhD's carefully tweaking up the chemical inputs over a period of hours or days. Where they hourly titrate the input chemicals to ensure they're at 99.99% purity. Where the cell is maintained with 843 degrees C on the cathode side, -177C on the anode side, maintained plus or minus 0.05 degree C thanks to the half-dozen HP $4,000 quartz resonator thermometers. Where the load is constant non-inductive fixed-value pure resistor. Where it sits on a marble lab bench with no vibration. Where it doesnt matter if a layer of micro bubbles of liquid plutonium forms on the cathode, as your PHD with the least senority can be mandated to start through a stereo microscope and scrape that gunk off with a nano-curette.
Then consider the operating environment for your typical car engine. Compare and Contrast. Hand in by the end of the hour. Points for neatness.
Um, you know when there's a temperature inversion between you and the nearest big city? And you start picking up radio and TV stations from that city that you normally never receive? Nature made you a temporary tunnel for radio waves.
p
Your typical fiber optic fiber does something much like this. The fiber has a gentle gradient of index of refraction from the center out. So light ends up traveling by the quickest path-- very close to down the exact center. Older fibers depended on light bouncing off the insides, zig-zagging its way down the fiber. That worked, but there were too many possible paths and the bits would end up coming out the other end slightly jittered in time.
Magnetic fields fall of as the CUBE of the distance, so don't expect this tablecloth to be all that useful. It will probably require no more than a centimeter between the sending and receiving coils, possible less.
Also note that any uncaptured power ends up being dissipated in the sending coil, so it will make a nice heating pad for your sore muscles. If you don't mind a magnetic field going into you as lagniappe.
From the pics it looks like a solder joint "failed". Now there are many possible reasons for a solder joint failing. I have no idea which one or combination of these are responsible:
The affected chip is one that normally gets quite hot in normal use-- the thermal stresses built up and mechanically failed the joint.
The chip is on a part of the PC board that flexes under normal or abnormal use. The joint flexed a few times and finally failed.
The board was improperly wave-soldered-- either too low a temperature, or the wrong alloy of solder, or not enough flux, or too high a humidity, or a myriad of other soldering errors.
The solder was defective or lead-free-- solder these days is mostly Tin, which isnt as good as a 36/63% tin/lead mixture. It's harder to get the right soldering temperature profiles with lead-free solder.
The solder had a high proportion of Tin and the laptop was expoased to many, many hot/cold cycles, going below about 35 degrees F. The element Tin has an unfortunately located crystal phase transition around 40 degrees F which results in crystal deformation. After enough cycles the Tin can crumble into dust.
Steve Jobs INTENTIONALLY specified this lead/tin alloy just so he could sell more PowerBooks!:)
UAC is like putting those loud beep-beep backing up alarms on every vehicle, from truck to skateboard. Eventually everybody learns to ignore the beep-beeping and the feature becomes worse than useless.
Yes I have. Please explain how that has anything to do with this subject.
We're talking about waves in the 10cm range. A phased array for this frequency range would be a whole lot larger than a laptop, and the focusing effects are only effective several wavelengths from the array. You'd have to make the whole room's ceiling one big phased array in order to deliver a few watts to a laptop-sized area. And the sidelobes would still be a couple factors of ten too strong for the legal limits. And if you accidentally wandered into the beam, instant cataracts!
Here's one data point regarding the toxicity of Mercury:: Oak Ridge
During the 1950's more than HALF the world's mercury was being pumped around a building in Oak Ridge, Tennessee.
Mercury dissolves lithium, and the US Govt wanted several tons of Lithium 6 isotope to make H-bombs with.
Due to a bit of carelessness, something like 200,000 pounds of mercury went missing. Some went as vapor into the air, some into the water, and a lot leaked from joints and pumps in the lithium works.
Now 200K pounds is enough, by current standards, to make everybody in the USA a drooling imbecile, or everybody in Tenessee a mouth-breathing moron, or everybody in Oak Ridge a politician.
Apparently none of those things have come to pass.
So just maybe we should turn down the hysteria about breaking a 10cc tube with a smidgen of mercury vapor in it.
Expecting nanotubes to act as "maxwell's Demons" is well on the way to Polyanna-Thinking. Fine for used-car ads, political spots, and grant proposals. But a bit far-fetched for rational discussion.
Plus on the economic issue, most nano-things cost kilobucks per square centimeter. Even if the cost came down by a factor of 10,000, it would still be uneconomical at ThunderDome prices.
Using biology as an example is a cop-out, unless you're willing to concede that Nanotechnology is just another name for "animal husbandry".
>Nanotechnology is a new engineering discipline.
No, it's been around for 20 years.
>but it's already an industry.
No, it's a buzz-word-- an industry would be building something. Nanotech has burnt up over $400 million in capital, with no tangible results other than sunscreen.
>-nothing insurmountable or fundamental.
Try reading up about the issue of scaling. About 97% of what's written about nanotech completely ignores basic physical laws.
In order for those tiny things to gather, they'd have to, individually, be able to sense, navigate, communicate, and move. You have to explain that basic stage first before you can assume they can do the job once aggregated.
Basic problem:
As far as I know, we can't build devices of convenient sizes and with unlimited funds to sense, navigate, communicate, move, and aggregate into any useful function. It's an awfully huge leap of faith to just ASSUME the devices can be built on a microscopic size, given that we can't do it on a convenient scale.
Anything nano must be possible, and good. At least that's the buzz.
But, hmmm, funny how you only hear this kind of buzz from people that have not a clue about the basic laws of scale, as related to surface area versus volume, wavelengths of radio and light, and surface tension.
In a nutshell, start with a cell-phone with camera, and ponder what happens as you shrink it by a factor of ten, again and again. Surmise what happens to it's audio and video sensor resolutions, the efficiency of xmitting antennas, the power available, and it's tendency to get washed away by precipitation.
Als, consider, it's just slightly possible that Michael Chricton is totally full of s**t. (Swarm)
Slashdot Mirror
- They sell more expensive ink that way.
- You'll notice your typical printing regimen uses much less yellow than the other shades, so if it's a trui-color cartridge, unless you're printing a lot of "skin tones", the yellow section will tend to still be mostly full when the other ones have run out, or at least "low".
- Many printers try to estimate the amount of ink used, but if you remove a print cartridge or reset the printer EROM, or the cartridge contacts get intermittent, many printers when they see a "unknown but used cartridge, assume it has unknown quantity and assume the worst.
- The printers with separate print heads and ink cartridges have a serious problem-- if the printhead runs out of ink the little teeasy tiny microscopic print head resistors blow out, requiring an expensive $40 printhead. On a HP D1xx printer, there are four of these. So the printer signals "ink low" when it's really probably still 1/3 full, just to protect the printheads.
- The printers with separate print heads and ink cartridges can get air-bubbles in the plumbing between ink cartridge and printhead if the ink runs low, leading to poor printing and printhead blowouts, so again they thy to err on the safe side.
Not very good reasons, but there they are...Only one teensy problem--
You can only send RANDOM BIT STREAMS.
The two endpoints, be they separated in time or space, get the same information all right. But mother nature sure is devious, the information is content_free. It's as random as can be. You can get the same quality of information by flipping a coin.
Lotsa Luck,
Conspiracies? CIA plot? Vooodoo?
Then again there's a cult of "scientists" that know with a small deltaT, you have a miniscule top efficiency. Been known to these cultists for centuries. On top of that loow theoretical efficiency, you impose the intrinsic inefficiencies of the Stirling Cycle, where hot and cold sections are mostly intermingled, leading to tremendous heat losses. Miniscule times teensy gives almost vanishing results. There are few Stirling engines that could even pay the interest on their original cost, even with a free source of heat.
Ergo they've been looked at every few years, then discarded by these fanatic scientists and physicists.
That's swell. However in military applications like this one they went with the Stirling as it's QUIET, not because of its efficiency (which is low). So low it's hard to find numbers. The ones in the technical peer-reviewed papers are around 3%. The ones in the glossy PDF's from places with "stirling" in their name are heavily caveated numbers around 50%. Guess which number I'd consider more reliable.
Searching the InterWebs finds a NASA press release quoting 20% efficiency. And that's with a deadly radioisotope that can supply 860C heat.
To believe Stirling cycle is superb you have to posit huge scientific industrial conspiracies, heretofore unachieved progress in bizarre materials, and quite a bit more. Lotsa luck.
Apples versus horsecollars. Not a logical or illuminating comparison.
And research into obscure areas is just fine, but there are plenty of areas that are not hopeless squared. This one
??? Argue all you want. A quick search of this "InterWebs" thing shows a LOT of argument about Stirlings. But you'd think after 200+ years of development there would be maybe at least just *one* working example where the efficiency was measured and usably high. Hmmm ......
Well whoopee-ding.
So they get one watt of sound power.
Now how many watts of heat did it take to generate that one acoustic watt? Deponent sayeth not.
General Carnot principles suggest a whole spitload of watts.
In general converting random motion, the lowest quality of energy, into periodic sound waves, a MUCH higher quality of energy, never happens by chance or with any notable efficiency. That principle has been known for going on 175 years now.
Now feed that very expensively obtained watt into a most efficient piezoelectric microphone. Microphones rarely go above 2% efficient.
To be sure, measure the temperature drop. I suspect you'll be lucky to get one degree of drop. Out of 480.
Divide that by the heat to sound efficiency and you get a number with an amazing and uninteresting number of leading zeroes.
I'll eat several hats if the heat to electricity efficiency factor exceeds 0.001
Even a Stirling engine can do better, and even that is totally useless.
- Good old Carnot's law. The efficiency is limited by the temperature drop across the device compared to the absolute temperature. Now take two thermometers, stick one up your butt and fart. compute the temperature difference. Divide by 483. That's your efficiency in converting heated gas into sound. Prolly about 0.005% as a rough approx.
- For a less gross example, pucker your lips and blow. Do this for five minutes or until you pass out. You probably feel warm-- that's the heat. How much acoustic power did you generate? Well a loud whistle is about 100dbA, about a hundredth of a watt. Efficiency, 0.004% at best.
- Piezoelectic efficiency. Well, it's really high-- for an acoustic transducer. The Interwebs seem to reveal no figures for this, and in general a high level of coyness is a way of hiding embarrasing numbers. Let's assume a best-case number of say 40%.
- The impedances. Crystals are very high impedance devices, putting out LOTS of volts at vanishingly small amps, which is bad news for us, as most of our power sinks are low impedance. Getting a few milliamps at 40KV is not very compatible with powering your laptop, which is about a million times lower in impedance. It's particularly inconcvenient converting tens of kilovolts downwards with economy and efficiency.
So sorry, probably much less than nothing to see here, just another bundle of our taxpayer's money spent on a totally pointless technical exercise.There are a lot of caveats in any use of fuel cells: * A lot of fuel cells work just fine in the lab. Where you have several PhD's carefully tweaking up the chemical inputs over a period of hours or days. Where they hourly titrate the input chemicals to ensure they're at 99.99% purity. Where the cell is maintained with 843 degrees C on the cathode side, -177C on the anode side, maintained plus or minus 0.05 degree C thanks to the half-dozen HP $4,000 quartz resonator thermometers. Where the load is constant non-inductive fixed-value pure resistor. Where it sits on a marble lab bench with no vibration. Where it doesnt matter if a layer of micro bubbles of liquid plutonium forms on the cathode, as your PHD with the least senority can be mandated to start through a stereo microscope and scrape that gunk off with a nano-curette. Then consider the operating environment for your typical car engine. Compare and Contrast. Hand in by the end of the hour. Points for neatness.
A much better material is "Dragonskin"-- it is flexible and breathes somewhat.
Um, you know when there's a temperature inversion between you and the nearest big city? And you start picking up radio and TV stations from that city that you normally never receive? Nature made you a temporary tunnel for radio waves. p Your typical fiber optic fiber does something much like this. The fiber has a gentle gradient of index of refraction from the center out. So light ends up traveling by the quickest path-- very close to down the exact center. Older fibers depended on light bouncing off the insides, zig-zagging its way down the fiber. That worked, but there were too many possible paths and the bits would end up coming out the other end slightly jittered in time.
Sorry, but magnets are dipole fields, the field strength drops off as the cube.
Magnetic fields fall of as the CUBE of the distance, so don't expect this tablecloth to be all that useful. It will probably require no more than a centimeter between the sending and receiving coils, possible less. Also note that any uncaptured power ends up being dissipated in the sending coil, so it will make a nice heating pad for your sore muscles. If you don't mind a magnetic field going into you as lagniappe.
UAC is like putting those loud beep-beep backing up alarms on every vehicle, from truck to skateboard. Eventually everybody learns to ignore the beep-beeping and the feature becomes worse than useless.
Yes I have. Please explain how that has anything to do with this subject.
We're talking about waves in the 10cm range. A phased array for this frequency range would be a whole lot larger than a laptop, and the focusing effects are only effective several wavelengths from the array. You'd have to make the whole room's ceiling one big phased array in order to deliver a few watts to a laptop-sized area. And the sidelobes would still be a couple factors of ten too strong for the legal limits. And if you accidentally wandered into the beam, instant cataracts!
During the 1950's more than HALF the world's mercury was being pumped around a building in Oak Ridge, Tennessee. Mercury dissolves lithium, and the US Govt wanted several tons of Lithium 6 isotope to make H-bombs with.
Due to a bit of carelessness, something like 200,000 pounds of mercury went missing. Some went as vapor into the air, some into the water, and a lot leaked from joints and pumps in the lithium works.
Now 200K pounds is enough, by current standards, to make everybody in the USA a drooling imbecile, or everybody in Tenessee a mouth-breathing moron, or everybody in Oak Ridge a politician.
Apparently none of those things have come to pass.
So just maybe we should turn down the hysteria about breaking a 10cc tube with a smidgen of mercury vapor in it.
Here someone is suggesting letting free many watts.
Just ain't going to ever be approved.
It doesn't take much power, under a watt, to make instant cataracts. Ask any old radar operator.
Plus on the economic issue, most nano-things cost kilobucks per square centimeter. Even if the cost came down by a factor of 10,000, it would still be uneconomical at ThunderDome prices.
>Nanotechnology is a new engineering discipline.
No, it's been around for 20 years.
>but it's already an industry.
No, it's a buzz-word-- an industry would be building something. Nanotech has burnt up over $400 million in capital, with no tangible results other than sunscreen.
>-nothing insurmountable or fundamental.
Try reading up about the issue of scaling. About 97% of what's written about nanotech completely ignores basic physical laws.
cart-before the horse:
In order for those tiny things to gather, they'd have to, individually, be able to sense, navigate, communicate, and move. You have to explain that basic stage first before you can assume they can do the job once aggregated.
Basic problem:
As far as I know, we can't build devices of convenient sizes and with unlimited funds to sense, navigate, communicate, move, and aggregate into any useful function. It's an awfully huge leap of faith to just ASSUME the devices can be built on a microscopic size, given that we can't do it on a convenient scale.
But, hmmm, funny how you only hear this kind of buzz from people that have not a clue about the basic laws of scale, as related to surface area versus volume, wavelengths of radio and light, and surface tension.
In a nutshell, start with a cell-phone with camera, and ponder what happens as you shrink it by a factor of ten, again and again. Surmise what happens to it's audio and video sensor resolutions, the efficiency of xmitting antennas, the power available, and it's tendency to get washed away by precipitation.
Als, consider, it's just slightly possible that Michael Chricton is totally full of s**t. (Swarm)
US audience:
Don't tell any Republicans about this.
The prez is already concerned about the possibility, and I quote from a speech: "human-animal hybrids".