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Comment A field full of two layers of firefighters. (Score 1) 106

As mentioned previously, my mental model of semiconductors and the like is a fireman's water brigade, were either the majority of the line has buckets or empty hands.

It helps if, instead of a line, you think of a LOT them standing in a two-D array (like in the yard of the burning building, or a section of a parade that's stopped to do a little demo). It's really three-D, but we'll want to use up/down for something else in a bit...

For metallic electron conduction everybody has TWO buckets, one for each hand, and when a guy by the fire throws a buck of water on it (bucket and all) on the fire, a guy farther back immediately tosses him a bucket, the guy behind him essentially instantly throws HIM a bucket, andso on. Hands are effectively never empty.

For semiconductors, imagine two layers of these guys, the second standing on the firsts' shoulders or on a scaffold right above them, and about enough buckets for each of the guys on the ground to have two and the guys on the scaffold to have none. (There's actually many layers of scaffold, but the rest are so far up that it's hard to get a bucket to them, so they mostly just stand around.)

Usually nothing useful is happening. Everybody on the bottom layer has both hands full of buckets, and it's hard to hand a bucket up to the guys on the top.
  - Electron-hole pair creation: Somebody comes up with the energy to heave a bucket up to the guys on the upper layer, leaving a guy with one hand empty in the lower layer. (Maybe somebody (a photon, for instance) comes along with a lacrosse stick and whacks a bucket up to a guy in the top row - dying or becoming exhausted and much weaker from the effort.) Now you've got one guy with a free hand in the lower layer (a hole) and one bucket on the top layer (a free electron).
  - Electron conduction in a semiconductor is that bucket on the upper layer. The guys there can hand it around easily, or toss it along a diagonal until it would hit a guy - who catches it. They're all standing on accurately-spaced platforms so the bucket can go quite a way before somebody has to catch it. Suppose there's a slope to the yard, with the fire at the bottom. Then, if tossed too far, the bucket might pick up substantial speed and knock the guy who catches it out of place (electromigration), or fall down to the lower layer and knock another bucket out of somebody's hand and bounce, ending up with TWO buckets on the upper layer and an empty hand below (avalanche electron-hole creation).
  - Hole conduction is when you've got an empty hand on the bottom layer: Now it's easy for a guy with two buckets to hand a bucket to a guy with only one, exchanging a bucket for an empty hand. But now the guy whose hand had been empty has two buckets and nobody in the downhill/toward-fire direction to hand a bucket to, while the guy who handed it off has an empty hand and can grab a bucket from somebody farther uphill / closer to the water source - or beside him, or diagonally. So "empty-handedness" (a hole) can move around as a persistent entity while the individual buckets gradually work their way in the general direction of the fire, only making a bit of progress "when a hole comes by". Though the water makes progress toward the fire, the action is all where the holes are making progress away from the fire.
  - Electron-hole annihilation: Somebody has a bucket on the upper layer when a guy below him has an empty hand. So he drops the bucket. CLANG! Ouch! Now there's no "free bucket" on the upper layer, no free hand on the lower layer, and the energy of their separation went somewhere else (knocking the guy sideways so he bumps into his neighbor and generally making the guys vibrate, "creating a guy with a lacrosse stick who runs off to whack at buckets", etc.)
  - P-type doping: A guy in the bottom layer had a sore hand and only brought one bucket to the fire, thus having a free hand from the start. He can take a bucket when a neighbor pushes it at him (the hole moves away). But he'd like to hand it off and have his sore hand free again (so holes tend to stick around at his site). It's lots easier to "make a free hole" by convincing him to hold a bucket in his sore hand than by tossing a bucket up to the guys on the scaffold, but does take a little effort.
  - N-type doping: One of the guys on the upper level really likes to hold a bucket, so he brought one with him. The guy next to him can grab it from him, but if another comes along he'll try to hold on to it a bit until somebody shames him into letting go again or wrestles it from him. It's lots easier to get him to let you use his bucket for a while than to pull one up from the guys on the ground, but it does take a little effort.
  - Tunneling through a potential barrier: There's a ridge across the field. It's hard to hand buckets up to the guys on the ridge, so they don't flow across it very well (unless someone at the side of the field is pushing the buckets really hard...) Occasionally the guys on one side of the ridge hand a bucket through the legs of the guys standing on the ridge to the guys on the other side.
And so on. B-)

I'm keenly interested in finding more material to read up on the observed Hall effect measurements. Thanks again for your contribution to the discussion.

The wikipedia article on the hall effect has a section on the hall effect in semiconductors, but both it and the reference it uses start from treating the hole as a charge carrier with a fixed charge and a mobility different from a free electron, and just computes formulai from there.

If the hall effect on hole currents were fallout from the hall effect on the individual electron bucket-transfers, rather than the hole acting like a positive charge carrier in its own right, you'd think it would go the other way

Comment Another useful vacuum tube: Thermionic converter. (Score 1) 106

Another vacuum tube technology with current applications and substantial advantages over semiconductor approaches to the same problems is the Thermionic Converter. This is a vacuum-tube technology heat engine that turns temperature differences into electric power - by boiling electrons off a hot electrode and collecting them, at a somewhat more negative voltage (like 0.5 to 1 volt), at a cooler electrode.

Semiconductor approaches such as the Peltier Cell tend to be limited in operating temperature due to the materials involved, and lose a major fraction of the available power to non-power-producing heat conduction from the hot to the cold side of the device. Thermionic converters, by contrast are vacuum devices, and inherently insulating (with the heat conducted almost entirely by the working electrons, where it is doing the generation, or parasitic infrared radiation, which can be reflected rater than absorbed at the cold side.) They work very well at temperatures of a couple thousand degrees, a good match to combustion, point-focused solar, and nuclear thermal sources.

Thermionic converters have been the subject to recent improvements, such as graphine electrodes. The power density limitation of space charge has been solved, by using a "control grid" to encourage to charge to move along from the emitter to the collector and magnetic fields to guide it (so it doesn't discharge the control grid and waste the power used to charge it).

Current thermionic technology can convert better than 30% of the available thermal energy to electrical power and achieves power densities in the ballpark of a kilowatt per 100 square cm (i.e. a disk about 4 1/2 inches in diameter). That's a reasonably respectable carnot engine. This makes it very useful for things like topping cycles in steam plants: You run it with the flame against the hot side so it is at the combustion temperature, and the "cold" side at the temperature of the superheated steam for your steam cycle. Rather than wasting the energy of that temperature drop (as you would with a pure steam cycle) you collect about a third of it as electricity.

It also beats the efficiency of currently available solar cell technology (and the 33.4% Shockleyâ"Queisser theoretical limit for single-junction cells), if you don't mind mounting it on a sun-tracker. Not only that, but you can capture the "waste heat" at a useful temperature without substantial impairment to the electrical generation or heat collection, and thus use the same surface area for both generation and solar heating. (Doing this with semiconductor solar cells doesn't work well, because they become far less efficient when running a couple tens of degrees above room temparature.)

Comment Re:Many a young engineer.... (Score 2) 106

... every schematic drawn by every semiconductor engineer got the arrow backwards.

As I heard it, The arrow is "backward" because Benjamin Franklin, when doing his work unifying "vitreous" and "resinous" electricity as surplus and deficit of a single charge carrier (and identifying the "electrical pressure" later named "voltage"), took a guess at which corresponded to a surplus of a movable charge carrier. He had a 50% chance to assign "positive" to the TYPICAL moving charge carrier in the situations being experimented with (charge transfer by friction between different substances, currents in metallic conductors, and high voltage discharges in air and water-in-air aerosols) and happened to guess "wrong".

Thus we say electrons have a negative charge, "classical current" corresponds to the sum of the flow of moving positive charge minus the flow of negative charge (i.e. the negative of the electron current, which is all there is in normal-matter metallic conductors), the arrowhead on diodes (and junction transistors) points in the direction of classical current across a junction, and so on.

But though it's the charge carrier in metallic conduction and (hard) vacuum tubes, the electron ISN'T the only charge carrier. Even in the above list of phenomena, positive ion flow is a substantial part of electrical discharge currents in air - static sparks and lightning. Positive moving charge carriers are substantial contributors to current as you get to other plasma phenomena and technologies - gas-filled "vacuum" tubes (such as thyratons), gas an LIQUID filled "vacuum" tubes (ignatrons), gas discharge lighting, arc lighting, arc welding, prototype nuclear fusion reactors, ...

Move on to electrochemistry and ALL the charge carriers are ions - atoms or molecular groups with an unequal electron and proton count, and thus a net charge - which may be either positive or negative (and you're usually working wit a mix of both).

And then there's semiconductors, where you have both electrons and "holes" participating in metallic conduction. Yes, you can argue that hole propagation is actually electron movement. But holes act like a coherent physical entity in SO many ways that it's easier to treat them as charge carriers in their own right, with their own properties, than to drill down to the electron hops that underlie them. For starters, they're the only entity in "hole current" that maintains a long-term association with the movement of a bit of charge - any given electron is only involved in a single hop, while the hole exists from its creation (by an electron being ejected from a place in the semiconductor that an electron should be, by doping or excitation, leaving a hole) to their destruction (by a free electron falling into them and releasing the energy of electron-hole-pair separation). They move around - like a charge carrier with a very short (like usually just to the next atom of the solid material) mean free path.

For me the big tell is that they participate in the Hall Effect just as if they were a positive charge carrier being deflected by a magnetic field. The hall voltage tells you the difference between the fraction of the current carried by electrons excited into a conduction band and that carried by holes - whether you think of them as actual moving positive charge carriers or a coordinated hopping phenomenon among electrons that are still in a lower energy state. Further, much of interesting semiconductor behavior is mediated by whether electrons or holes are the "majority carrier" in a given region - exactly what the hall effect tells you about it.

So, as with many engineering phenomena, the sign for charge and current is arbitrary, and there are both real and virtual current carriers with positive charge. Saying "they got it wrong" when classical current is the reverse of electron current is just metallic/thermionic conduction chauvinism. B

Comment Re:Vacuum tubes handle EMP's better (Score 1) 106

"No point progressing since the bombs are gonna fall any day now. Then where will your fancy silicon highways and databases be?"

Given that the Internet Protocol and much of the rest of the networking technology that still underpins the Internet were developed as part of a cold-war program to create a communication system that could survive a nuclear attack that destroyed most of it, and still reorganize itself to pass messages quickly, efficiently, and automatically among any nodes that still had SOME path between them, your post seems to come from some alternate universe to the one I inhabit.

Comment Re: Micropayments? (Score 2) 219

Well, part of it is that even a small payment can still incur a psychologically large cost. If each user post here on /. cost one cent to read, would you want to have them load automatically? Probably not, many of them are not worth that much, and you could quickly run up a bill of a few hundred dollars a year on that sort of thing from this site alone. So instead you'd have to take more time to think about what was worth spending even a little on, because it adds up and the price doesn't really match the value to you of the thing you'd be paying for.

Something similar happens when people have metered or capped Internet usage compared to at least nominally unlimited usage.

You really can't avoid this problem unless the micropayment is so small that it is likely not worth the cost to implement. I suppose if I knew that a year's worth of micro payments for me, for everything I use, was no more than about a dollar a year in total, it wouldn't be so much that it would feel like I was wasting money on the Internet. But because the average user doesn't want to spend a noticeable amount ever, and there really aren't that many users in comparison to sites, the resulting pie of money wouldn't be much to split up. (Especially once you reduce the amount to account for lower average incomes elsewhere in the world)

Comment The IRS keeps its hooks in US citizens who leave. (Score 2) 364

I'd also move my operation to Ireland if I could.

What's stopping you?

The US tax code. The US keeps its hooks in its citizens and companies, for decades, if they try to leave, even if they move out and renounce their citizenship.

The US does this to a far greater extent than other countries who generally don't tax their citizens if they're out of the country for more than half a year. (This is where "The Jet Set" came from: Citizens of various non-US countries who had found a way to earn a living that let them split their time among three or more countries every year and avoid enough income tax to live high-on-the-hog, even on an income that otherwise might be middle-class.)

Only really big companies, with armies of lawyers, can find loopholes that let them effectively move out of the US to a lower-taxing alternative. You'll note that TFA is a lament about how one managed to escape, and how the US might "close THIS loophole" to prevent others from using it.

Comment Re:Simple Fix for H1B Visa Problem (Score 1) 55

Simply require that H-1B visa holders must be paid at least the 90th percentile (or 95th if you like) wage for their field.

Plus any amount that the employer would have to pay into a government entitlement program for a US employee that he doesn't need to pay into said program for a foreigner on H1B (or other work visa systems).

It's even fair. If the program is, say, a retirement program that the visiting worker can't benefit from, shouldn't he have the money to buy a replacement for it elsewhere?

Comment Dow makes LOTS of stuff. (Score 1) 491

... by everyone's favorite munitions manufacturer: Dow Chemical.

Dow makes a LOT of chemical stuff. Some of it's useful to the military.

If their Dow Corning partnership-subsidiary hadn't been hammered into bankruptct by a bunch of (later shown to be bogus) suits claiming medial harm from their silicon breast implants, we might have had hybrid cars a couple decades earlier, out of Detroit rather than Japan, using lenticular, glass fiber, super flywheels, rather than batteries, for energy storage.

Comment Yeah, you'd think that ... (Score 1) 108

It's my understanding that when you're committing a crime, the last thing you want to do is break even worse laws that will get you a worse sentence if caught.

Yeah, you'd think that. And some of them actually do think of that.

But many criminals don't think very well, or very far ahead. Not thinking about being caught is common. Not expecting to be seriously inconvenienced if they ARE caught is common also.

Think about it: How is "Send me a bitcoin or your insulin pump will deliver a fatal dose!" different from armed robbery for a fat wallet? "Give me a bunch of money or I shoot you!" And a bunch of them DO shoot - (VERY) often even if they GOT the money.

The threat of law-enforcement escalation for murder doesn't seem to have stopped up-front-and-personal armed robbery. Why should it stop distant-and-anonymous ransomware?

Comment Trying to stop it also has bad history. (Score 1) 588

The problem is that the whole thing lends itself to "wackadoodles". You have an entire system of belief based on nothing but hearsay ... Then people believe this stuff with no evidence for it ... take some part of that "literal truth" and decide that it really means you need to go murder some people.

Unfortunately, trying to stop it also has bad history. Meme-infected people tend to remain meme-infected until death when opposed (because opposition tends to reenforce such memes), and forcible brain-washing normally doesn't work (though it may get them to pretend to have changed their beliefs, in order to make the pain stop or avoid death or mutilation). Meanwhile there's a long history of people infected with OTHER religious memes using governmental power to wipe out the believers in competing religions.

The history of Europe, in the centuries before the framing of the US' Constitution, was full of disastrous religious wars, and many of the religious groups in the Americas were here to escape this. One of the groups was "The Separatists", the (colorfully dressed "Pilgrims" of the Plymouth colony, often conflated with the "Puritans" who settled a bit farther north) who held, as a core belief,the separation of the church and the state (because each would corrupt the other).

This ideal was built into the first Amendment of the Bill of Rights, pushed by many leaders of small religions (who knew that, if the government picked and promoted a church, it was unlikely to be theirs, and the religious wars would start over here). The US federal government (and, though "incorporation", the states and their subdivisions) is prohibited from doing anything, for or against, any specific religion (including dogmatic non-religion).

And Islam was known to the framers. It shows up in their debates, where it is held up as an example of a non-Christian religion for which the same arguments can be made, for and against, as are made with respect to Christian sects.

So tracking people by religion, as religion, is right out, and any such plan would almost certainly be gutted the first time it hits the courts.

If the government wants to go after the I.S. brigands, it needs to frame the laws and activities in terms of their civil actions, without respect to any religious motivations or professed religious claims.

Comment What happens if you EAT this salad? (Score 1) 39

Does it get broken down into something harmless in the stomach? Or do YOU get conductive lines along YOUR plumbing?

It's not a minor thing: For starters the heartbeat propagation is partly electrical. Better-than-blood-plasma conductors laid out along the plumbing of the heart might affect the heartbeat in a dangerous manner.

Comment Conspiracy theories and the "Second Cover" (Score 1) 42

... there's always room for a conspiracy theory like the NWO controlling both the US and German governments and then some to suppress the truth.

The problem is that people do tend to work together to advance their own interests, and do so in secret to reduce opposition from others. That is the definition of conspiracy. Such activity is not purely mythical or rare - it's pervasive, inherent to the human condition.

Governments, and groups within and/or associated with them, have a long track record of doing such things, getting away with them for years, and having (some of) them come to light decades later. It's always the same story: "Oh, yes, back in the bad old days there were such things going on. But that stuff isn't done any more. (And anybody who claims such stuff is happening now is a nutcase, so pay no attention to him.)"

Then, maybe 30 or 40 years later what was going on THIS time comes to light, and the story repeats. Or somebody blows the whistle while it's still going on and presents evidence (often at great cost to himself), and then it's "That's just a rogue person/agency/group. We're bringing them to heel." or "It's a corrupt administration. Replace the head of state with a different one (maybe from the other major party but keep the same two parties in power) and it's all taken care of." Yeah, right.

Snowden revelations, ECHELON, Watergate, COINTELPRO, Pentagon Papers, Hanford Experiment, Tuskegee Experiment, Factor 8, Abscam, Ng Lap Seng, Iran-Contra, MK-Ultra, Operations MOCKINGBIRD, PHOENIX, and CHAOS, ... I could go on for pages, and that's just big, US (sometimes with allies), stuff that came to light in MY lifetime.

The government has whole agencies tasked with conspiring in secret to collect information and/or intervene to interfere with any opposition to its interests. The US has "Black Budgets" to unauditably fund such activity, and the Department of Defense, alone, spends an estimated $50 BILLION a year on its portion of this (as of 2009).

With their activities occurring in secret, there is much temptation to, and limited checks on, also targeting the biggest risk to the people currently in power in any government: The citizens of the country.

"Spook" agencies have a number of techniques to keep these conspiracies hidden, and one that has come to light (and is appropos) is the "Second Cover". This consists of spreading TWO cover stories: The first is plausible. The second is tinfoil-hat fruitcake material, lightly hidden. Anybody who figures out the first cover IS a cover and starts digging finds the second cover. Then they usually either give up (rather than dig for a third level) or you get new material for the tabloids, and another boost for the "conspiracy theories are ALL crazy talk" meme. (And it also helps that occasionally they DO try out the odd piece of mystic bulls**t, just to see if any of it, like some herbal medicine, DOES work.)

I generally assume (as did The Framers) that this sort of creeping (or galloping) encroachment is inherent in governments, is going on (and having new project starts) all the time, we usually can't tell, through the fog of misdirection, what's going on NOW, and the job of the people, like a farmer clearing weeds and trimming orchard trees, is to continually cut it back to levels that don't ruin our own lives and livelihoods.

6 Curses = 1 Hexahex