Dan's Data letters #147
(page 3)
Publication date: 1-July-2005.Last modified 03-Dec-2011.
Infocom made the only fun one
What does "parsing" mean when I try to open an Adobe Illustrator file in Photoshop? Also, what is a "parser module", and why might it be having trouble parsing the Illustrator file?
Derek
Answer:
Photoshop's a "raster image" program - it generally works with bitmaps,
made of pixels. Illustrator's a structured drawing program - it generally works with shapes (what used to be called
vector graphics), which never break up into blocky pixels
no matter how close you zoom (Photoshop's text is structured if you're using a non-bitmap font,
but that's not important right now).
When you load a structured image into a raster program, it has to "rasterise" it - you tell it the resolution you want, and it draws the vector image in pixels for you. That's what Photoshop's parser module is doing.
You don't mention what versions of Illustrator and Photoshop you're using, but it doesn't matter, because I don't know what incompatibilities there are between what versions anyway. Essentially, though, if the Illustrator file isn't actually corrupt (that is, if Illustrator can still load it with no problems), then there's some point of incompatibility - apparently layered, stroked paths could do that with some version or other of the two programs, and there were compatibility problems with .ai files in general, at some point at least. Or the Illustrator file might have a placed image that Photoshop can't find.
Try saving the file as Encapsulated PostScript (EPS) from Illustrator; Photoshop may like that better.
The bolt through the neck's the tricky part
It's July, which means it's time to start thinking about Halloween costumes. Well, for me, at any rate. This year I'm thinking of doing Frankenstein's Monster - any decent party will end with me grunting and lurching around, so it seems like a good fit. What I'd really like to do, though, is incorporate cool-looking electrical discharges into the costume. Maybe shoot inch-long sparks from one hand into grounded metal? Yeah, that would properly horrify my long-suffering girlfriend.
Is there any way to accomplish this that would be portable? A Van de Graaf generator, perhaps? Some arrangement with a Tesla coil?
I vaguely remember an uncle demonstrating the desired effect to me when I was little, but I can't remember if it was the wily, irrepressible uncle or just the wildly irresponsible one. And anyway I suspect his solution involved mains power, which I'd prefer to avoid for many reasons. Bring on the SLA batteries, though, if that's what it'd take.
Oh, also: if at all possible, I would prefer to accomplish the above without stopping my heart or suffering severe burns. But I realize that may be asking a lot.
Tom
Answer:
Yes, a human not tethered to some piece of electrical equipment can shoot electrical sparks (as opposed to pyrotechnic
ones), but all of the easy ways of doing it are really dangerous.
What you want is a static electricity generator, like a Van de Graaf generator, that you can carry around. Lots of volts, practically no current capacity.
The trouble is that these things tend to be bulky, and need their charged parts to be well away from anything even vaguely electrically connected to their other parts. That's why a Van de Graaf generator has that stalk with the belt running through it; it's there to separate the dome from the base with a decent length of nice insulative plastic.
There are lots of other electrostatic generator designs, but I doubt any of those would be amenable to portable use, either.
Disturbingly, it is very likely that this actually works just fine. You won't get big sparks from it, though.
Once you start talking Tesla coils, you get into the "doable, but lethal" department.
Tesla coils, like various other high tension sources, can deliver more than enough current to kill. This is part of their charm, of course; there's a big difference between the weedy zap-zap-zap of even a big electrostatic generator and the big fat scary arcs coming off a Tesla coil's top, or climbing up a Jacob's Ladder.
Lots of nerds have made little tiny versions of these sorts of things to use as joy buzzers; those "shocking pens" you can buy in joke shops nowadays use the same technology. They can't generate more than a teeny spark, though.
House Of PC Doom
I run a computer store and have had a computer I built a few months ago returned to me four times with pretty much the same problem every time.
Intermittent problems - i.e. three ticking hard drives, one non-POSTing motherboard, one power supply obviously dead and smelling. I have replaced the entire system with new parts, but now it's back, with a dead mobo but OK power supply.
My presumption is that all the problems are the result of brownouts or dodgy power in the customers' home. I can't seem to find any info on the Web about this, and a friend said that you might find it challenging.
Question: How can I determine the cause of death? Is there a way of detecting how the power supply died? Would you expect a brownout to destroy a motherboard and make a hard drive deteriorate but not fry the CPU with P4 connector, or a graphics card with the additional Molex power? The latest power supply functions 100% on the shop test system.
I'm starting to feel like UPS's should be mandatory with new systems.
Sam
Answer:
I would say bad power is very likely to be the problem, but the results are unusual.
Any half-decent PC PSU should be able to protect the rest of the system components from "normal" mains problems (as opposed to extreme stuff like nearby lightning strikes). For this reason, computers are pretty darn resistant to toxic power. You can feed the PSU too much or too little voltage, and its outputs may drop low in the latter case and cause the computer to become flaky, but every PSU should have a "crowbar" circuit that quite reliably shorts the output and blows the PSU fuse, rather than subject the computer to significant overvoltage.
It is, however, easy to buy crappy PSUs that cope poorly with bad input. They probably don't qualify for any kind of approval sticker, but importers generally deal with this problem with a strategy involving a big roll of approval stickers and large brass balls.
If you've been using quality brand-name PSUs - nothing fancy, grey-steel AOpens will do - then this shouldn't be a problem. If you've been using $AU7-wholesale units - stop.
Assuming reasonable PSU quality, power that can blow computer hardware up is likely to toast lots of other things in the house. Your customers' home should be a graveyard for light bulbs and appliances.
If it isn't, then something fishy's going on. Perhaps just the circuit to the room where they're setting up the computer is bad. DIY electricians, and the ravages of time, can do terrible things to house wiring (which may not have been good in the first place).
For this reason, I wouldn't just stampede to setting them up with a UPS (or power conditioner - though, if they just have crap power where they live, a whole-house conditioner may greatly improve their lives). If their power and their neighbours' power is lousy and the power company can't/won't help, then there's probably no point to getting them to have an electrician look the place over. If they're the only ones with the problem, though, or it only happens in one part of their house, then they definitely should have someone credentialled crawl over the ceilings and under the floors, before the joint burns down.
Yes, power weirdness can cause components to die in odd combinations, assuming the PSU's not behaving as it should. Modern mobos usually regulate down 5V to run the CPU; if the PSU's delivering overvoltage on that rail, the regulators will burn up and kill the mobo, but the CPU will probably survive. The PSU controller board can be similarly fragile.
I'm envisaging someone nearby on the same substation who's got some awful-power-factor load that dumps a buttload of energy into the mains when they shut it down, but I'm not an expert. It could just be a screwed-up "pole pig" transformer feeding their whole street 270VRMS. Or it could be some unexpected weirdness - perhaps they're using the computer in a metalworking shop, and blowing the shavings out before they bring it back to you. Who knows.
How hard can it be?
Thanks for such wonderful and fun pages about magnets. It was really nice to see those cool ferrofluid effects!
I would appreciate if you can advise as to how to make magnets. I have an electronic engineering background, but have never done this before. I want to make tiny magnets, say 4mm by 4mm or 6mm by 6mm, of the power of 4000 to 5000 Gauss (the higher, the better).
Meetul
Answer:
You won't be able to do it.
Even plain ferrite magnets (the ordinary cheap brittle black ones), with a peak surface field strength of about 1000 Gauss, can't be made at home. They're fabricated under extreme pressure, then magnetised with a very brief, very high power pulse.
More powerful permanent magnets - samarium cobalt and the generally superior modern neodymium-iron-boron - are made in a similar way, but each stage is more difficult.
You might be able to make something vaguely similar and magnetise it with some gimcrack coil-and-capacitor-bank arrangement, but your coil would probably rip itself apart with each pulse.
You could also make an electromagnet with more power than any NIB can manage, but not in the size you want, and keeping it cool probably wouldn't be easy.
Fortunately, NIB magnets with the power you need are now available cheaply in various sizes (well, the little ones are cheap, anyway), so I recommend you buy off-the-peg.
Compare...
While browsing my favorite Bittorrent site the other day, I ran across some odd documents on "Running a Gasoline Engine on Hydrogen Using Water".
From the name alone, it sounds utterly ridiculous. Interestingly, however, there's quite a bit to them, not a small amount of garbage one would expect to find with something so outrageously titled. I thought you'd find it somewhat interesting, although I'm sure that the "plans" are probably useless.
I'm not an expert on cars, nor can I read electronic schematics, so I am unable to prove that this is complete, but I thought you might find it to be engaging, if only for a few minutes.
Greg
Answer:
Greg attached the files he found; the same, um, information is
available on the highly
independent-thinking
Spirit of Ma'At site.
There are more related, um, discoveries, here.
The water-powered car isn't anything like the worst of the stuff on this site, but it is still, of course, complete rubbish.
The errors in the document come thick and fast, so I'll only bother with the lynchpin problem: Electrolysing water takes more energy than you'll get back by combusting the resultant oxygen and hydrogen.
If you expect to be able to propel a car (using a much-less-than-100%-efficient engine) and produce enough surplus energy to keep the electrolysis going (and the electrolysis won't work at all on plain tap water - you'd have to make it conductive by adding salt, or something), you're asking for the electrolysis to be, oh, maybe a thousand per cent efficient, at the very least.
To deal with this problem, free-energy nutballs usually actually say they're doing some kind of phenomenally-efficient over-unity electrolysis, or producing some mystic mix of gases that delivers more power than the mere molecules involved could be expected to. None of them can stump up a working model, of course.
It's possible to convert piston engines to run on hydrogen, but it's not easy, and even if you do, you don't end up with a perfectly clean result. The high combustion-chamber temperatures mean you can get lots of nitrogen-oxide pollution if the car's breathing air, plus minor pollution from lubricant combustion.
But, as you say, these plans certainly do go on and on. They clearly weren't a five-minute writing job.
I think there are three possibilities, here:
1: The author of the document is delusional, and thinks all this is true. Maybe they even think they've made it work.
2: The author is a believer, but hasn't actually done this; they're trying to encourage people to do what they'll only be able to do if they believe it's been done already (a la The Unsolvable Math Problem).
3: The author's deliberately seeing whether These People Will Believe Anything, and has trumped up a nice complex collection of white-elephant instructions to see how seriously they're taken. Whenever someone says they've done it, that someone is marked as a nut or rip-off artist.
This last can, of course, result in a certain amount of collateral damage among the gullible.
...and contrast
While I was shopping for cars, one of the lowly car sales trolls brought up the United Nuclear web page. After which, he predicted the demise of the gasoline powered automobile and the wide scale adoption of solar panels and wind mills in a "hippies dancing in a circle, daises falling from the sky" kind of way. What's the deal? Another perpetual energy scam or should I start hording all the water I can?
This is the site.
Joel
Answer:
United Nuclear, despite their Flash Gordon name, seem to be pretty much
on the level. They don't make any extraordinary claims for their tech - for a start, they admit that filling hydrogen
cylinders takes time, especially when you're doing it from small-ish solar panels or wind turbines. An hour of modest
average-20kW driving, by someone with (say) a 200 watt solar array for recharging, inescapably requires 100 hours
times the reciprocal of the efficiency of the engine and the hydrogen generator to replenish. That means that if you
want eight hour recharge time for your one-hour commute, you're probably going to need a monster 10kW array.
United Nuclear also show realistic numbers of cylinders in converted cars, they specifically deride the car-running-on-water scam artists, and they're selling (allegedly) seamless petrol/hydrogen conversion kits, so you won't be stranded if and when you run out of H2.
By the standards of conversion kits, this seems to be a very professional one - if it's a scam, you'd think they'd come up with some more attractive lies.
Whether the United Nuclear product is a generally useful one is still open to question, though. It's one thing if you for some reason can't get gasoline at all, but if you can, even at European prices you're likely to find a hydrogen conversion takes some time to pay for itself (United Nuclear don't seem to have any prices up yet).
Home-generated hydrogen is, however, undeniably about as clean a fuel (taking into account pollution produced in making your car, making your fuel, burning your fuel, disposing of worn-out stuff...) as you can get. Hydrogen power in general is at present a giant boondoggle (since the only source we currently have for bulk hydrogen is cracking fossil fuels...), but adventurous people could well find United-Nuclear-type solutions highly agreeable.
The big plus here is that you've still got gasoline power to fall back on, which is not the case with fully electric vehicles. There's a lot to be said for electric if you're interested in alternatively-powered-transport at the moment and willing to make a hobby out of it, though. A car driven by a bunch of cheap lead acid batteries can manage quite enough range and quite fast enough charging for most people's purposes (100km range and overnight charging are enough for an awful lot of urban applications), and lead acid may be disgusting but it's also highly recyclable, and if you want to make something that can smoke its tyres, that's perfectly possible too.
If you charge from house current then you're shifting the pollution to the power plant (particularly in countries like Australia that get most of their power from coal), and wasting some of the power in transmission and the charge process itself, but power plants are much more efficient than petrol engines, and have tall smokestacks. They dump their pollution somewhere, but at least they don't dump it straight into every neighbourhood you drive through.
Nope, still not done! Click here to go to the fourth and final page of this letters column!
