I won't be lectured on it by someone who has seen one show!
I agree, don't be lectured by someone who has seen only a single show. As for myself, I've seen many BBC news broadcasts, and I've read the BBC news webpage _daily_ for many years.
My point was that BBC, if it really is against large multinationals, certainly has no problem with them sponsoring rebroadcasts. Take that however you wish, but don't ignore it simply because you falsely presume I'm a brainwashed American that only saw a single BBC news broadcast.
While the BBC's bias is well documented, it is AGAINST multinational corporations. To suggest that the BBC is in league with them is, frankly, ludicrous.
Bullshit. I watched the BBC World News here in the US last night (on Maryland public access tv). At the end they listed the sponsors of the program, several of them large multinationals.
They don't necessarily denounce open source software in general (at least, not that I've heard of.)
Yeah, they embrace OSS when it suits them. For example, back in 1998 I used Windows NT 4.0 at work. I had the NT Resource Kit, which came with PERL and some other open-source stuff licensed under GPL (PERL is dual-licensed, IIRC).
Anyway, the Resource Kit's book had the GPL printed in the back. It was VERY amusing to see the preamble of the GPL, which basically denounces predatory closed-source software, in a book by the Microsoft Press.
That's also when I was getting started in Linux, so I found it especially amusing.
I would also imagine that the tension of the space elevator cable would make it nearly immune to plane attacks. Ie, an incoming plane would probably have it's wings ripped off by the line.
In WWII the Brits used a 'wall' like this to protect against incoming German missiles/rockets. Helium balloons (big) would be tethered to the ground w/ a steel cable. Incoming missiles had the wings/fins ripped off and couldn't fly further inland.
Use a 'bucket' in which the surface is pressurized well above atmosphere. You can get the liquid column height as high as you want.
Or for fun, pressurize the 'bucket' such that the liquid surface is a few inches below the top of the straw (probably difficult because the fluctuations will be too large). Then one can drink just like it's a normal sized cup w/ straw.
Some other posts describe this a little, here's some more info.
They use a "dilution refrigerator" to get that cold. Dilution refrigeration uses a mixture of He3/He4 (mash) and cycles between two phases of the mixture (a He3 rich phase and a He3 dilute phase). The He3 and He4 are both liquids at this point.
Here's a basic overview of cryogenics. Liquid Nitrogen (LN2) liquifies at 77 K in 1 atmosphere. N2 is abundant, and LN2 is priced cheaper than milk. LHe4 liquifies at 4.2 K, and costs (here in the USA) about $4 per liter. I think it's much more expensive elsewhere in the world, but helium is mined w/ natural gas companies, so is more plentiful here than elsewhere. LHe3 is a rare isotope of Helium and vastly more expensive. It liquifies (I think) around 3K, and costs several hundred dollars for a few gaseous liters (here in USA).
So one can easily get to 4.2 K by dipping something in LHe4. One can employ evaporative cooling, and 'pump' on the LHe4 dewar, and get down to temperatures of about 1.5K. Perhaps slightly lower for bigger pumps. This cooling is quite easy and cheap to do, but often doesn't get low enough in temperature. If one has LHe3, that can be pumped on to get down to about 200 mK. But this is difficult because LHe3 is so expensive, and closed-cycle pumps are needed so as not to waste the cryogen.
Dilution fridges can get to lower temperatures. We just got one of these fridges in our lab, and using that I've cooled some samples down to about 20 mK. Dilution fridges have fundamental limits around 6 mK or so, but physical limits usually kick in earlier than that due to equilibrium between cooling 'power' and heating (mostly due to radiation and vibration). The basic thermodynamics are actually quite similar to your standard fridge, and you can think of it as He3 'evaporating' out of the mash, absorbing energy as they do so. And later the He3 is condensed back into the mash.
Fridge operation basically has a mixing chamber, which is the 'cold' point of the system. One hopes to create the phase boundary between the two phases here. The mixture absorbs heat from the sample, and the dilute phase travels up to the still, where it's pumped on by some big-ass pumping lines. The liquid is effectively warmed up, gets circulated around and re-condensed by a cold block at about 1.5 K. [This block is called the 1-K pot and is only pumped LHe4]. There's a flow impedance put in (to calibrate the pumping power with the circulation to get the phase separation at the right place). Then it's back into the mixing chamber. Meanwhile there are many heat exchangers along the way, exchanging heat from the incoming rich phase and outgoing dilute phase. The cooling power of the fridge is greatly increased depending on these heat exchangers. The effective sample size in our fridge is a cylinder about 1 inch diameter and 10 inches long. The dewar itself is about 7 feet tall and 3 feet diameter, and there's a rack of electronics and four pumps to go with it. So it's a big unit for a relatively small cooling volume.
Dewers are designed using stainless steel and other components to minimize thermal conductance to room temperature as much as possible. Radiative heating, however, is a problem. The dewar is evacuated between the 'cold' part and the outside, to minimize conductance. Radiation goes as T^4, and this power law is greatly exploited in dewar design. If one surrounds the 'cold' part of the dewar with a LN2 shroud, the cold part sees radiation at 77K instead of 300K. This factor of ~1/4 translates to a drop in radiative heating power of about 1/250.
Beyond this dewars use superinsulation, whereby aluminized mylar is wrapped around many times (with spacers), so each successive layer sees a colder temperature. So the 20mK part of the dewar might only be surrounded by an effective layer of a few K. These methods cut radiative heating down by factors of millions or more.
i've never heard of anybody taking off half or more for simple calculation mistakes. For difficult problems w/ lots of calculation (usually non-numerical but strictly symbolic) I don't take off any points for minor mathematical errors. If they do something conceptually wrong, e.g. integrate over the wrong regions, etc, then I might take off a point or two.
Yeah, that's how we generally ran it. Partial credit for everything, we didn't care too much about the final answer. And as i explained in a different reply above, we didn't want to give students with fancy calculators an advantage over those that couldn't afford one.
Anyway, many of the problems we did were in algebraic form where calculators wouldn't have helped (unless it had some symbolic software similar to Mathematica). But of course no introductory physics class is complete without being able to predict and calculate physical measurement values. Thus, some of the problems were of the numerical variety.
But yes, we're of course more concerned about the general problem than the results. And if they left the answer as 3000 x 0.0003 they'd only have a small penalty, as long as their methods were correct. But it was still shocking that they would tell me to my face that they couldn't do this without a calculator.
I agree with you completely. Calcaulators SHOULD be allowed. At this level we don't care about student's arithematic, or even algebra. Maybe some of the applied calculus.
But the problem is with people with super-duper graphing calculators and storing tons of extra 'equations' that they would otherwise have to derive, etc. That's where the problem came from.
We decided in the class that the rich students with the fancy calculators shouldn't have an advantage over students that couldn't buy one. Therefore no calculators allowed at all, with the values of the physical parameters chosen such that the numbers work nicely.
We were just shocked that some students couldn't do the relatively simple arithematic without their calculators.
It's even worse than you imagine. I was a TA for the introductory physics course for biological majors at Johns Hopkins University. Because of things like graphing calculators, as well as the ability to store vast amounts of textbook information in calculators/PDA's, students weren't allowed to use calculators on the exams (so as to level the playing field). In turn, the math was made easier (ie, no finding the square root of 743.2 for instance).
It was really sickening that several students couldn't do relatively simple math or utilize scientific notation. For example, a simple quiz question could boil down to the student multiplying 4000 x 0.00007 and not being able to do it! Some students told me to my face that they couldn't do this type of stuff without a calculator! Sometimes after I explain it to them and point out how obviuos it is, they kind of slap their foreheads for not knowing it. But still, these kind of simple scientific notation calculations should have been taught to them at least in high school, if not earlier.
The scary part is this school is one of the top top pre-med schools, and many of these students will go on to become top doctors in their fields. Some of whom were baffled by simplistic mathematical calculations.
An amusing anecdote, although probably urban legend, goes as follows. Understand that for pre-meds physics is usually considered the hardest class because it's the only one where full-blown memorization doesn't work. A pre-med, frustrated with his/her physics class goes to complain to the professor. He/She says "Physics is stupid, why do pre-meds need to know physics anyway?". The physicist responds "Oh, it saves lives." Premed inquires how. Physicist responds "It stops the idiots like yourself from becoming doctors."
Yeah, that's exactly my point. Your date order is only marginal better than the standard American system, unless you happen to write times backward.
How would you normally write 16 minutes and 35 seconds after 3 pm? Either 3:16:35 or 15:16:35 (depending on 24-hour time being used or not). Here in USA we would say this time as "three-sixteen pm" or maybe "three-sixteen pm and 35 seconds".
The American format is annoying, I agree. (I'm American). In my computer data files and scientific notebooks I use format YYYY-MM-DD, and occasionally for frequenctly-created files YYYY-MM-DD-HH-MM (second MM is minutes). So that's why I had a problem with your system, as it would cause the exact same kind of problem.
A parent post above mentioned that the reason American date formats are like this is that we tend to say June 5th, and I guess Europeans and others tend to say 5th of June. But time here in USA is hour:minute (10:34). So the only real inconstincy in the American system is the position of the year, which should come first instead of at the end.
How would you write and say the time and date? I imagine it too would have inconsistencies.
Dude, LSL totally rocked! Do you remember in the first few titles those attempts to 'weed out' the kids from playing by asking series of pop-culture questions?
Seriously, those games were funny as hell. I think the first 'boss key' I ever saw was one of the LSL's, where it put some kind of histogram of condom durability on the screen, hysterical. Especially for a 10 year old.
What you are talking about is really just Quantum Field Theory explained from a different perspective, which actually has been done since at least Landau and Lifshitz (see their course on Theoretical Physics, volumes 2 and 4). Classical field theory is essentially electrodynamics (relativistic classical EM fields). Quantum Field Theory basically quantizes the field operator, but is difficult for a number of reasons. (Ie, in the 3+1 four-vector, the momentum is a standard operator but time is more of a parameter than operator, so one cannot merely generalize non-relativistic QM that easily. It involves going through alot of clever manipulation.)
And magnetism does exist, the magnetic and electric fields are really one and the same (in the proper 4-vector formalism). Magnetism can come from electron spin (explained very well in QFT) as well as moving charges (moving electron, for example). Spin has alot of quantum weirdness due to being angular momentum that's always 'just there' and discretized. But it's explained well enough w/ quantum field theory and group theory.
Re:Damn. Now I feel old.
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Holy shit, I finally met someone else that used the GEAP!!! Best program with the funniest name.
That program was the definitive moment for me, when I started delving into the 3-ring binder manuals to figure out how to do obscure stuff! And it's the only program I ever used on the TRS-80 that would force a reboot and set some register on the reboot to adjust the memory size, or something like that.
Yeah, GEAP was awesome, but the only standard font I remember about it was what excited my 12 year old mind the most, the 'minicube' font. I did make some custom fonts with it too, one that actually looked kind of cool and was 'dots' forming the letters.
Ah, the memories. But seriously, you're the first other person I met that has used GEAP!!
It seems very promising considering that a magnetic field moves at the speed of light once it's been created.
Well, it's really the 'electromagnetic field' that can propogate at the speed of light in a vacuum (in the form of photons, which are of course the fundamental quanta of electromagnetic radiation.
Magnetic and electric fields are quite related, and only independent phenomena in time-independent processes (ie, electrostatics and magnetostatics). Namely, if you write Maxwell's Equations out and put all time derivatives to zero you really get separation of electric and magnetic fields. But for real systems, changes of one of these induces spatial variations of the other. So they're truly interconnected, and in fact they're most conveniently written in 4-dimensional form that describes special relativity perfectly.
Electrons can tunnel across a gate: can variables like spin do the same thing? If so, that's another barrier.
Yes, it's still the electrons tunneling across. And it's quite appropriate that you use the word 'barrier'.
There are spin tunnel junctions, where the electron tunnels through an insulator, and people are measuring how long the spin can be preserved if the electron tunnels into a standard metal.
Ie, after enough scattering points the spin will be effectively randomized.
But yes, electrons are tunneling, and in some cases the spin of the electron (whether up or down) determines how well it will tunnel through the barrier. So spin is really another parameter that can be controlled to make spin-transistors or spin valves more dynamic than traditional transistors.
controlling magnetism on such a granular level only ups the chance that a few bits somewhere will go awry.
You're doing the same thing with 'traditional' electronics anyway. As things scale smaller and smaller, eventually the charge of a single electron will be the limiting factor within a bit, and even before that level is reached, fluctuations of several electrons could be large enough to cause things to "go awry" as you say.
The whole point of spintronics (or magnetoelectronics, it's less buzzword-trendy name) is to add an extra degree of freedom to electronics. Ie, instead of using components that switch on spin-independent electronic charge, one is now adding this extra component that can be switched/amplified/etc.
It's effectively opening up whole new doors, and spintronics represents the 2nd-rapidest movement of technology from lab to market (after the transistor, of course). The field is in its infancy right now, but has huge potential to revolutionize the types of electronic components that exist.
As you say, working on such nanoscale systems makes things really hard, and we're trying now to study and overcome these technical difficulties. But people are hopeful this will produce interesting devices, such as using the spin up/down eigenstates of the electron as the basis states for qubits in quantum computers, for example. Or many other quantum-dependent phenomena that are effectively averaged-out in standard electronics.
I played mostly D&D in my day, and some of the others (marvel, shadow run, MERPS). Originally I thought D&D was pretty unrealistic, because you'd be in sword fights and rarely would the players actually get permanently damaged (ie, lose limbs), and you'd fight just as well at 1 HP as at full HP, also. And the way of gaining experience seemed kind of arbitrary. Ie, a thief kills a dragon and can suddenly climb walls better.
So I started envisaging a game that kept track of these things, gave experience when the right skills were used, tried to keep pain/damage separate, etc. And I was planning out some mathematics to keep all this straight. It seemed to be complicated, but I thought it would make the experience better.
Anyway, when my friends and I started playing MERPS I remember there was alot of adding and calculating to keep track of during battle. Enough that it was a real PITA (it was awhile ago, so I might not remember exactly). So it was then and there I realized firsthand that too much math really destroys the fun of the game, instead of making it more realistic.
So my suggestion for math/rulesset is KISS (Keep It Simple, Stupid). Leave more time for character development, roleplaying, and interaction than keeping track of stats and rules, IMHO. And I think D&D is fairly good in this regard, alhtough I do want to try Amber but never got around to it.
Re:Damn. Now I feel old.
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Hey, I did almost the same thing, although my D&D generation utility didn't print out nearly as cool as yours did. But I was making graphics on the Epson MX-80 multilined w/ independent programs, which was pretty fun at the time. Although it got pretty tiresome pretty quickly.
I still think the instruction manual for the MX-80 was one of the best/funniest. It had little snippets like 'Now before you go out and try to clone the Mona Lisa look at what we can do with this other option'. It was hysterical.
This was discussed a few years ago by a professor in soft condensed-matter physics, in one of my classes. Silly putty is a common example of this, as someone said.
I don't remember the physical details, but the basis is that these complex materials don't specifically act as fully solid or fully fluid, and in this case the 'phase' of the material depends on the timescale. Long times (ie, slow) it looks fluid, but short time scales (a quick jab) it responds quickly to the shear and looks more like a solid.
I think quicksand is similar too, which is why people that panic if they fall in can't get out, but slow careful movements help one get out easier.
Well, if you're talking about bar jokes, I remember the rounds of them after Challenger blew up in 1985, and some of these resurfaced after Columbia blew up last year. Same thing with JFK junior's plane crash, and damn near any other widely-reported public event,
tragedy or not.
Remember how we all pointed and laughed when Mir got into trouble?
Who the hell is we? I know all the scientists I've worked with, here in the USA, were genuinely conerned w/ Mir. Even w/ the general community that would show up at some of the open-community popular space talks I've attended. I don't know of anybody that 'pointed and laughed' at Mir. Maybe you were around freshman college engineering students that thought the world works as easily as their introductory lab classes?
No idea, but enough that they throw the plants in a giant furnace and all the organic matter vaporizes away. Well, at least that's what I understood from talking with my friend about it 5 years ago, maybe i'm remembering all wrong.
Do a search on slashdot for "carbon nanotube" and "nanowire".
There has been quite a bit of interest in those areas.
Okay, I did just that. Of the first 15 search results, only three articles even had the word "nanotech" or "nanotechnology" mentioned anywhere in either the article or the slashdot comments. Two of these articles had a comment from a single slashdot user 'Goldsmith' who works with nanotubes and understands they fall into the field of 'nanotechnology'. The third article actually did have quite a few mentions. So that's 1 in 15.
I know there is some interest about nanotubes here on/., I see this primarily for space elevator applications, occasionally for novel solid-state mechanisms (ie, new memory, etc).
But my whole point was that for discussions on 'nanotechnology' it is rarely understood that research of carbon nanotubes falls into that category. And a huge block of comments on any nanotech subject are full of posts associating nanotech = nanites, which is the false association I was trying to do away with in the first place.
Slashdot Mirror
I agree, don't be lectured by someone who has seen only a single show. As for myself, I've seen many BBC news broadcasts, and I've read the BBC news webpage _daily_ for many years.
My point was that BBC, if it really is against large multinationals, certainly has no problem with them sponsoring rebroadcasts. Take that however you wish, but don't ignore it simply because you falsely presume I'm a brainwashed American that only saw a single BBC news broadcast.
Bullshit. I watched the BBC World News here in the US last night (on Maryland public access tv). At the end they listed the sponsors of the program, several of them large multinationals.
Yeah, they embrace OSS when it suits them. For example, back in 1998 I used Windows NT 4.0 at work. I had the NT Resource Kit, which came with PERL and some other open-source stuff licensed under GPL (PERL is dual-licensed, IIRC).
Anyway, the Resource Kit's book had the GPL printed in the back. It was VERY amusing to see the preamble of the GPL, which basically denounces predatory closed-source software, in a book by the Microsoft Press.
That's also when I was getting started in Linux, so I found it especially amusing.
In WWII the Brits used a 'wall' like this to protect against incoming German missiles/rockets. Helium balloons (big) would be tethered to the ground w/ a steel cable. Incoming missiles had the wings/fins ripped off and couldn't fly further inland.
Or for fun, pressurize the 'bucket' such that the liquid surface is a few inches below the top of the straw (probably difficult because the fluctuations will be too large). Then one can drink just like it's a normal sized cup w/ straw.
They use a "dilution refrigerator" to get that cold. Dilution refrigeration uses a mixture of He3/He4 (mash) and cycles between two phases of the mixture (a He3 rich phase and a He3 dilute phase). The He3 and He4 are both liquids at this point.
Here's a basic overview of cryogenics. Liquid Nitrogen (LN2) liquifies at 77 K in 1 atmosphere. N2 is abundant, and LN2 is priced cheaper than milk. LHe4 liquifies at 4.2 K, and costs (here in the USA) about $4 per liter. I think it's much more expensive elsewhere in the world, but helium is mined w/ natural gas companies, so is more plentiful here than elsewhere. LHe3 is a rare isotope of Helium and vastly more expensive. It liquifies (I think) around 3K, and costs several hundred dollars for a few gaseous liters (here in USA).
So one can easily get to 4.2 K by dipping something in LHe4. One can employ evaporative cooling, and 'pump' on the LHe4 dewar, and get down to temperatures of about 1.5K. Perhaps slightly lower for bigger pumps. This cooling is quite easy and cheap to do, but often doesn't get low enough in temperature. If one has LHe3, that can be pumped on to get down to about 200 mK. But this is difficult because LHe3 is so expensive, and closed-cycle pumps are needed so as not to waste the cryogen.
Dilution fridges can get to lower temperatures. We just got one of these fridges in our lab, and using that I've cooled some samples down to about 20 mK. Dilution fridges have fundamental limits around 6 mK or so, but physical limits usually kick in earlier than that due to equilibrium between cooling 'power' and heating (mostly due to radiation and vibration). The basic thermodynamics are actually quite similar to your standard fridge, and you can think of it as He3 'evaporating' out of the mash, absorbing energy as they do so. And later the He3 is condensed back into the mash.
Fridge operation basically has a mixing chamber, which is the 'cold' point of the system. One hopes to create the phase boundary between the two phases here. The mixture absorbs heat from the sample, and the dilute phase travels up to the still, where it's pumped on by some big-ass pumping lines. The liquid is effectively warmed up, gets circulated around and re-condensed by a cold block at about 1.5 K. [This block is called the 1-K pot and is only pumped LHe4]. There's a flow impedance put in (to calibrate the pumping power with the circulation to get the phase separation at the right place). Then it's back into the mixing chamber. Meanwhile there are many heat exchangers along the way, exchanging heat from the incoming rich phase and outgoing dilute phase. The cooling power of the fridge is greatly increased depending on these heat exchangers. The effective sample size in our fridge is a cylinder about 1 inch diameter and 10 inches long. The dewar itself is about 7 feet tall and 3 feet diameter, and there's a rack of electronics and four pumps to go with it. So it's a big unit for a relatively small cooling volume.
Dewers are designed using stainless steel and other components to minimize thermal conductance to room temperature as much as possible. Radiative heating, however, is a problem. The dewar is evacuated between the 'cold' part and the outside, to minimize conductance. Radiation goes as T^4, and this power law is greatly exploited in dewar design. If one surrounds the 'cold' part of the dewar with a LN2 shroud, the cold part sees radiation at 77K instead of 300K. This factor of ~1/4 translates to a drop in radiative heating power of about 1/250.
Beyond this dewars use superinsulation, whereby aluminized mylar is wrapped around many times (with spacers), so each successive layer sees a colder temperature. So the 20mK part of the dewar might only be surrounded by an effective layer of a few K. These methods cut radiative heating down by factors of millions or more.
i've never heard of anybody taking off half or more for simple calculation mistakes. For difficult problems w/ lots of calculation (usually non-numerical but strictly symbolic) I don't take off any points for minor mathematical errors. If they do something conceptually wrong, e.g. integrate over the wrong regions, etc, then I might take off a point or two.
Yeah, that's how we generally ran it. Partial credit for everything, we didn't care too much about the final answer. And as i explained in a different reply above, we didn't want to give students with fancy calculators an advantage over those that couldn't afford one.
Anyway, many of the problems we did were in algebraic form where calculators wouldn't have helped (unless it had some symbolic software similar to Mathematica). But of course no introductory physics class is complete without being able to predict and calculate physical measurement values. Thus, some of the problems were of the numerical variety.
But yes, we're of course more concerned about the general problem than the results. And if they left the answer as 3000 x 0.0003 they'd only have a small penalty, as long as their methods were correct. But it was still shocking that they would tell me to my face that they couldn't do this without a calculator.
But the problem is with people with super-duper graphing calculators and storing tons of extra 'equations' that they would otherwise have to derive, etc. That's where the problem came from.
We decided in the class that the rich students with the fancy calculators shouldn't have an advantage over students that couldn't buy one. Therefore no calculators allowed at all, with the values of the physical parameters chosen such that the numbers work nicely.
We were just shocked that some students couldn't do the relatively simple arithematic without their calculators.
It was really sickening that several students couldn't do relatively simple math or utilize scientific notation. For example, a simple quiz question could boil down to the student multiplying 4000 x 0.00007 and not being able to do it! Some students told me to my face that they couldn't do this type of stuff without a calculator! Sometimes after I explain it to them and point out how obviuos it is, they kind of slap their foreheads for not knowing it. But still, these kind of simple scientific notation calculations should have been taught to them at least in high school, if not earlier.
The scary part is this school is one of the top top pre-med schools, and many of these students will go on to become top doctors in their fields. Some of whom were baffled by simplistic mathematical calculations.
An amusing anecdote, although probably urban legend, goes as follows. Understand that for pre-meds physics is usually considered the hardest class because it's the only one where full-blown memorization doesn't work. A pre-med, frustrated with his/her physics class goes to complain to the professor. He/She says "Physics is stupid, why do pre-meds need to know physics anyway?". The physicist responds "Oh, it saves lives." Premed inquires how. Physicist responds "It stops the idiots like yourself from becoming doctors."
How would you normally write 16 minutes and 35 seconds after 3 pm? Either 3:16:35 or 15:16:35 (depending on 24-hour time being used or not). Here in USA we would say this time as "three-sixteen pm" or maybe "three-sixteen pm and 35 seconds".
The American format is annoying, I agree. (I'm American). In my computer data files and scientific notebooks I use format YYYY-MM-DD, and occasionally for frequenctly-created files YYYY-MM-DD-HH-MM (second MM is minutes). So that's why I had a problem with your system, as it would cause the exact same kind of problem.
A parent post above mentioned that the reason American date formats are like this is that we tend to say June 5th, and I guess Europeans and others tend to say 5th of June. But time here in USA is hour:minute (10:34). So the only real inconstincy in the American system is the position of the year, which should come first instead of at the end.
How would you write and say the time and date? I imagine it too would have inconsistencies.
No, but according to your logic you should use Y/M/D in decreasing order as per your time example.
Seriously, those games were funny as hell. I think the first 'boss key' I ever saw was one of the LSL's, where it put some kind of histogram of condom durability on the screen, hysterical. Especially for a 10 year old.
And magnetism does exist, the magnetic and electric fields are really one and the same (in the proper 4-vector formalism). Magnetism can come from electron spin (explained very well in QFT) as well as moving charges (moving electron, for example). Spin has alot of quantum weirdness due to being angular momentum that's always 'just there' and discretized. But it's explained well enough w/ quantum field theory and group theory.
That program was the definitive moment for me, when I started delving into the 3-ring binder manuals to figure out how to do obscure stuff! And it's the only program I ever used on the TRS-80 that would force a reboot and set some register on the reboot to adjust the memory size, or something like that.
Yeah, GEAP was awesome, but the only standard font I remember about it was what excited my 12 year old mind the most, the 'minicube' font. I did make some custom fonts with it too, one that actually looked kind of cool and was 'dots' forming the letters.
Ah, the memories. But seriously, you're the first other person I met that has used GEAP!!
Well, it's really the 'electromagnetic field' that can propogate at the speed of light in a vacuum (in the form of photons, which are of course the fundamental quanta of electromagnetic radiation.
Magnetic and electric fields are quite related, and only independent phenomena in time-independent processes (ie, electrostatics and magnetostatics). Namely, if you write Maxwell's Equations out and put all time derivatives to zero you really get separation of electric and magnetic fields. But for real systems, changes of one of these induces spatial variations of the other. So they're truly interconnected, and in fact they're most conveniently written in 4-dimensional form that describes special relativity perfectly.
Yes, it's still the electrons tunneling across. And it's quite appropriate that you use the word 'barrier'.
There are spin tunnel junctions, where the electron tunnels through an insulator, and people are measuring how long the spin can be preserved if the electron tunnels into a standard metal. Ie, after enough scattering points the spin will be effectively randomized.
But yes, electrons are tunneling, and in some cases the spin of the electron (whether up or down) determines how well it will tunnel through the barrier. So spin is really another parameter that can be controlled to make spin-transistors or spin valves more dynamic than traditional transistors.
You're doing the same thing with 'traditional' electronics anyway. As things scale smaller and smaller, eventually the charge of a single electron will be the limiting factor within a bit, and even before that level is reached, fluctuations of several electrons could be large enough to cause things to "go awry" as you say.
The whole point of spintronics (or magnetoelectronics, it's less buzzword-trendy name) is to add an extra degree of freedom to electronics. Ie, instead of using components that switch on spin-independent electronic charge, one is now adding this extra component that can be switched/amplified/etc.
It's effectively opening up whole new doors, and spintronics represents the 2nd-rapidest movement of technology from lab to market (after the transistor, of course). The field is in its infancy right now, but has huge potential to revolutionize the types of electronic components that exist.
As you say, working on such nanoscale systems makes things really hard, and we're trying now to study and overcome these technical difficulties. But people are hopeful this will produce interesting devices, such as using the spin up/down eigenstates of the electron as the basis states for qubits in quantum computers, for example. Or many other quantum-dependent phenomena that are effectively averaged-out in standard electronics.
I played mostly D&D in my day, and some of the others (marvel, shadow run, MERPS). Originally I thought D&D was pretty unrealistic, because you'd be in sword fights and rarely would the players actually get permanently damaged (ie, lose limbs), and you'd fight just as well at 1 HP as at full HP, also. And the way of gaining experience seemed kind of arbitrary. Ie, a thief kills a dragon and can suddenly climb walls better.
So I started envisaging a game that kept track of these things, gave experience when the right skills were used, tried to keep pain/damage separate, etc. And I was planning out some mathematics to keep all this straight. It seemed to be complicated, but I thought it would make the experience better.
Anyway, when my friends and I started playing MERPS I remember there was alot of adding and calculating to keep track of during battle. Enough that it was a real PITA (it was awhile ago, so I might not remember exactly). So it was then and there I realized firsthand that too much math really destroys the fun of the game, instead of making it more realistic.
So my suggestion for math/rulesset is KISS (Keep It Simple, Stupid). Leave more time for character development, roleplaying, and interaction than keeping track of stats and rules, IMHO. And I think D&D is fairly good in this regard, alhtough I do want to try Amber but never got around to it.
I still think the instruction manual for the MX-80 was one of the best/funniest. It had little snippets like 'Now before you go out and try to clone the Mona Lisa look at what we can do with this other option'. It was hysterical.
I don't remember the physical details, but the basis is that these complex materials don't specifically act as fully solid or fully fluid, and in this case the 'phase' of the material depends on the timescale. Long times (ie, slow) it looks fluid, but short time scales (a quick jab) it responds quickly to the shear and looks more like a solid.
I think quicksand is similar too, which is why people that panic if they fall in can't get out, but slow careful movements help one get out easier.
Well, if you're talking about bar jokes, I remember the rounds of them after Challenger blew up in 1985, and some of these resurfaced after Columbia blew up last year. Same thing with JFK junior's plane crash, and damn near any other widely-reported public event, tragedy or not.
Who the hell is we? I know all the scientists I've worked with, here in the USA, were genuinely conerned w/ Mir. Even w/ the general community that would show up at some of the open-community popular space talks I've attended. I don't know of anybody that 'pointed and laughed' at Mir. Maybe you were around freshman college engineering students that thought the world works as easily as their introductory lab classes?
No idea, but enough that they throw the plants in a giant furnace and all the organic matter vaporizes away. Well, at least that's what I understood from talking with my friend about it 5 years ago, maybe i'm remembering all wrong.
Okay, I did just that. Of the first 15 search results, only three articles even had the word "nanotech" or "nanotechnology" mentioned anywhere in either the article or the slashdot comments. Two of these articles had a comment from a single slashdot user 'Goldsmith' who works with nanotubes and understands they fall into the field of 'nanotechnology'. The third article actually did have quite a few mentions. So that's 1 in 15.
I know there is some interest about nanotubes here on /., I see this primarily for space elevator applications, occasionally for novel solid-state mechanisms (ie, new memory, etc).
But my whole point was that for discussions on 'nanotechnology' it is rarely understood that research of carbon nanotubes falls into that category. And a huge block of comments on any nanotech subject are full of posts associating nanotech = nanites, which is the false association I was trying to do away with in the first place.