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Below are the 20 most recent journal entries recorded in
Alan's LiveJournal:
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| Saturday, December 19th, 2009 | | 4:06 pm |
Question for a physicist and/or chemist
I have some wild rice. The instructions on it say to boil some water in a saucepan, stir in the rice, cover, reduce heat to a simmer, and wait a while. When I stir the rice into the boiling water, I also stir in some butter and a spice mix (sugar, powdered soy sauce, onion, sesame seeds, garlic, and some other stuff). I mix everything thoroughly, cover it (so I can't see what happens), reduce the heat, and wait. When the rice is done, I uncover it, and all the sesame seeds are in a ring around the edge of the pan. The ring is maybe an inch thick; the pan is about 8 inches in diameter. The butter and sugar are mixed throughout and not clustered in any place, but the other spices, like the sesame seeds, seem to be in higher concentrations in the ring and lower concentrations in the center of the pan. I have a gas-powered stove, if that makes a difference. Why does this happen? | | Monday, December 14th, 2009 | | 10:54 pm |
| | Friday, October 16th, 2009 | | 3:21 am |
Ligature Alternatives in LaTeX
I've been corresponding with Dario Taraborelli and Will Robertson, and we have concluded a couple things about LaTeX and alternative glyphs for ligatures: ( Don't bother reading if you don't use LaTeX ) So, I feel like I just leveled up in typography. Sure, this example is overly flowery to the point that the typesetting detracts from the poem itself, but it's more to illustrate a point than to make good typesetting. Note that I use two different glyphs for the 'ss' ligature, two different ones for 'ck', two different 'll's, and two different 'cl's. Also, I finally have a use for the dotless 'i' (in "Vine," my V of choice collided with the dot). Other fun typography tricks are scattered throughout, but they're more for my personal enjoyment than yours. | | Thursday, September 24th, 2009 | | 8:49 pm |
| | Monday, September 14th, 2009 | | 10:33 pm |
| | Sunday, September 6th, 2009 | | 5:36 pm |
Reading the Canterbury Tales, old school
After my previous encounters with the Canterbury Tales, I've decided to read the entire thing. As before, I think that reading a modern translation loses the interesting parts of the language and screws up the poetry, so I want to read it in Middle English. and just because I can, I'm reading (a copy of) a 600-year old handwritten version. Those are images of the Hengwrt ("HENG-urt") manuscript, which was probably written sometime between 1400 and 1410 (note that Chaucer himself died in 1400, but it's hard to get closer to when he was alive). The images are very high quality; click the "all sizes" button towards the top to enlarge it a bit, then the "original resolution" link to see its true glory. I wish there was a way to set the default resolution higher, but I don't know if that's possible. Sure, I could read a version with original spelling in a modern font, and towards the end I probably will. but for the moment, the novelty of reading a handwritten manuscript hasn't worn off, so I'm persisting. It took a bit of time to get the hang of the handwriting and grammar, so in the interests of helping others follow in my footsteps, here is an illustrated guide to reading the manuscript. ( Letters and the Alphabet )( Grammar )( Spelling and Vocabulary )( Further Tips and Resources )If you have any further questions/suggestions, I'd be happy to answer them and add them above. Now that you've got some idea what's going on, here are the first few lines to start you off: ( The first few lines, with my own translation ) | | Thursday, August 20th, 2009 | | 8:38 pm |
C++ is bad: structs aren't the same as structs
Here's a fun little problem. Suppose you've got a system that makes use of the following struct: struct User {
unsigned int user_id;
unsigned short access_level;
float account_balance; // stored as US dollars
}Your system is ridiculously well-tested, all the tests pass, everything works totally fine. I'll be so bold as to say it's (kinda) bug-free. One day, you decide to add a new field to the User struct, a string called name. You recompile everything, and suddenly all kinds of tests fail! New users have all kinds of access levels, some have account balances in the billions while others have accounts worth negative billions. What happened, why, and how do you fix it (without removing name again)? Edit: and no, the code does not rely on brittle assumptions about the value of sizeof(User), nor does it break type safety and have unsafe casts or void*'s pointing into the middle of Users. That would be too easy.( The answers, and more! )Bonus question (independent of C++): storing the account_balance as a float (or even as a double!) is a terrible/dangerous idea; do you know why? | | Monday, August 17th, 2009 | | 9:37 pm |
Oh, yes.
 I don't care if it's old; it's new to me. | | Friday, July 31st, 2009 | | 11:04 pm |
Will It Lens? Temperature Breakthrough!
In case you missed it, here are the other parts of the Will It Lens? series. I know I haven't updated in a while, and I've got a huge backlog of pictures. So, part will be discussed here and I already have enough for another post as well. Remember that all the safety warnings from the other posts in the series still apply here, though I don't have anything new to add. Thanks for all the suggestions you've given us; we've tried some, and there have been quite a few good ones! ( Improvements to our setup )Anyway, results. Take a guess what this is:  ( The answer, and more results )I've got more pictures, but I'll save those for the next post. | | Friday, June 19th, 2009 | | 12:22 am |
| | Monday, June 15th, 2009 | | 12:06 am |
The photograph lies at my feet, falls from my fingers, is in my hand.
Dearest Internet, I write you today to share a discovery that excited my very being. I have found a wonderful connection between two ideas in which I merely dabble, and the way they complement each other so perfectly has given me new insight into both. The phrase "strawberries and cream" comes to mind. I am, of course, referring to quantum electrodynamics and video games. If the complementarity is not immediately obvious, let me direct your attention to a particular video game, Braid. Oh, Internet, it is a marvelous game, full of challenge and fun! In the way that Portal is a puzzle game wherein you must manipulate space to solve the puzzles, Braid is a puzzle game wherein you manipulate time. Braid is also an homage to Super Mario Brothers, which gives it a nostalgic feel. But on top of the usual "go left," "go right," and "jump" commands, you have at your disposal a "rewind time" button that is your main tool throughout the game. You control a character named Tim, whose goal is to go from the door on the left of the level to the door on the right side, while solving any puzzles preventing this (yes, I am simplifying, but that's the important part for now). Although the connection to QED may already be coming into focus, I should like to take a moment to remind you about the discipline. As you may recall, Internet, a man named Richard Feynman worked many a year on QED. He invented something called Feynman Diagrams, which are a very simple way to visually represent interactions between particles. He drew them as graphs with time along one axis and space along another, such as this:  In this image, the horizontal axis is time and the vertical axis is space. Depicted is one possible interaction between an electron and a photon. If one views time as monotonically moving forward (in the intuitive sense by which one normally perceives it), the photon coming down from the top spontaneously degenerates into an electron-positron pair (note that the positron is an anti-electron), and then the positron encounters the electron near the bottom of the diagram, and the two annihilate each other and turn into another photon. However, there is another way to view this event. Anti-particles behave just like their (non-anti) counterparts moving backwards in time, since they have opposite charge and opposite spin but are otherwise identical. In other words, my good Internet, we could just as easily view this diagram as depicting an electron moving along the bottom of the diagram, then spontaneously "turning around" and moving backwards in time, while shooting off a photon as it reverses direction. It continues to move up the diagram, traveling backwards through time, and then spontaneously reverses its direction once more to travel forwards through time, sending out another photon as it does so. Although this photon gets sent backwards in time, we would perceive it normally because the photon is its own antiparticle (because it has no charge). This reminded me quite strongly of certain levels in Braid, wherein time goes forwards as Tim moves to the right and backwards as he moves to the left. Here is an example, though it contains spoilers if you have not yet played the game. To give a better illustration of their similarity, consider the following diagram. Living things are in blue, photons are in red, and objects and platforms are in black.  If one were playing the game, one would see Tim come out of the door at the bottom left of the image, travel to the right (going forwards through time) until time E, then shoot out a photon, turn around, and jump up onto the platform (going backwards in time), jump over the Goomba at time B (Goombas can only be killed when going forwards through time). Tim would then turn around at time A (shooting a photon to the left in the process), jump forwards through time and land on the Goomba to kill it, then jump at time D to get to the platform with the door and exit the level. If, instead, we needed to watch these events as time monotonically increased, we would observe a photon on the platform and a Tim on the floor. At time A, the photon spontaneously decays into a Tim-antiTim pair. The Tim jumps immediately, while a moment later the antiTim unjumps. At time B, a Goomba comes into existence and is killed by the descending Tim. The antiTim, meanwhile, is high above and dodges the event. At time C, the Tim and antiTim collide, annihilate each other and become a photon again, though this photon decays into another Tim-antiTim pair at time D. The Tim jumps and the antiTim unjumps. Then the platform winks out of existence, and the antiTim falls through the space where it used to be. At time E, the antiTim encounters the Tim from the floor, the two annihilate each other and become a photon. The platform materializes above, the remaining Tim lands on it and encounters the final door, finishing the level. When I first realized this, it was a very exciting connection for me. I imagine, dear Internet, that you now share my spark of insight. If you desire to play Braid for yourself, it is available for download on XBox, Windows, and Mac. The demo is free, and the entire game is $15. | | Sunday, May 3rd, 2009 | | 6:46 pm |
| | Monday, April 20th, 2009 | | 2:37 am |
| | Thursday, April 9th, 2009 | | 12:54 pm |
Will It Lens? Table of Contents
    Welcome, all! Here are links to everything in the "Will It Lens?" series. - Part 1: introduction, melting pennies, dimes, toothpaste, Tylenol, milk, chalk, gourd, can.
- Part 2: equipment upgrades, CDs, disposable silverware, brass penny, burned pennies.
- Part 3 (Food Edition): popcorn, grape, kumquat, Frosted Mini Wheat, jelly beans, Reese's Pieces.
- Part 4: wood, quarter, soap, dishwasher detergent, bacon, egg, honey, seashell, almonds, gummy bears, M&Ms.
- Part 5 (Temperature Breakthrough): marshmallow, peeps, copper, iron, sand, glass
- More to come
soon eventually!
- Gallery of all pictures: This contains every picture we took. There's a lot of junk in here; the good pictures are in the blog posts above.
     FREQUENTLY ASKED QUESTIONS AND SUGGESTIONS (updated) - Can you melt glass?
This surprised us, but yes! Normal glass is more properly called "sodalime glass," which has a much lower melting point than pure silicon dioxide (which we originally thought glass was made of, and which we haven't been able to melt yet). However, we have trouble melting clear things because they don't absorb the sunlight. Nonetheless, we melted a dark brown glass in part 5. - Can you melt sand?
Kinda. The sand we tried is a mixture of quartz, feldspar, and iron. We can melt the last two, but we haven't melted quartz yet. Look at part 5 for more details. - Can you lens electronics?
We probably could, but we don't want to because the fumes are really noxious. There's lead and other stuff that's terrible for your lungs in there. - Can you use a second lens to focus the light even more?
No, that's not how optics works. For a slightly more thorough answer, see the Light Sharpener FAQ over at cockeyed.com. - Where did you get the lens? How much did it cost?
I think we got it from here. When we ordered it, I think it was about $120, plus shipping. If you include the wood for the frame and stand, the welding goggles, and the skillet, we've probably spent over $200 on lens-related stuff so far. - You should lens something that will burst and explode all over the place!
That would be very entertaining, but we need to clean everything up before lunch is over, so we're not doing anything too messy in the foreseeable future (no unopened pop cans, no aerosols, etc.). If we ever take the lens out to the middle of the desert, we will consider lensing messy things. - You should lens an iPhone, iPod, or other hip status symbol.
First, see question 3 about electronics. Then, remember that we're paying for all of this with our own money. We'd prefer not to lens anything that costs more than a couple dollars. Everything we've tried so far has cost under $1 each (almost everything is under $0.25 each). - Isn't it illegal to destroy money?
Not unless you do it with the intent to defraud someone. Remember the last time you went to the zoo? You probably saw one of those machines that will take your penny, flatten it out, and stamp an image of a penguin or something on it as a souvenir. Melting a penny is no more illegal than one of those machines.
Other articles that link to this series: | | Saturday, April 4th, 2009 | | 11:28 pm |
Will It Lens? Part 4
If you've missed it, here are parts one, two, and three of our adventures with a 4'x3' fresnel lens, along with a gallery of all the pictures. Our lens arrived with a corner chipped off, so the lens company sent us a second one for free (which also had its corner chipped off on arrival, but we didn't get a third for free). I've been holding off writing this post because I was hoping to title it "Episode IV: A New Lens," but we still haven't built the frame for the second lens or the frame for the mirrors that will reflect light from both lenses onto a single point. So, instead of waiting for that to happen, I'm posting the results I've already got. The same SAFETY NOTES as before apply, as always. In lieu of new safety warnings (we haven't had any new dangers come up!), I've got a few tips for anyone trying to duplicate this. ( Some tips for fellow lensers ) On to the results! ( Pictures of new results )As always, if you have ideas of stuff to lens, I'd be happy to try them out. Until next time, be safe and have fun! Edit: In part 5 we achieve much higher temperatures! | | Thursday, March 12th, 2009 | | 10:31 pm |
Mother of All Funk Chords
Oh man, this is awesome! and as icing on the cake, the creator cites all of his sources! This is why current "IP" rights need to swing further towards fair use: so you can do this sort of awesomeness. The kid with the trumpet just played a scale; the real value here was added by the remixer, and I think it's bullshit that legally, that trumpet player could send a DMCA takedown notice for this. To the best of my knowledge, the trumpeter has no such intentions; I'm just making a hypothetical here. Hopefully this sort of remixing will convince the musicians who don't get it yet that it's important to allow everyone to have fair use rights. Damn this stuff is sweet! | | Thursday, March 5th, 2009 | | 11:57 pm |
| | Sunday, March 1st, 2009 | | 3:15 pm |
The hawks are circling Iran again
What the crap is this!? Here are some of today's headlines: If you just glanced at today's headlines, would you think Iran was building a nuke and was likely to have it very soon? I certainly would. It's only after you read the articles that you find out the actual "story" is that Iran theoretically has enough uranium atoms to make a bomb but would first need to enrich them to become weapons grade, and they won't have the technical capability to do that for years to come. What the articles don't even mention is that the uranium is part of Iran's civilian power program, it's purified enough to be used in a nuclear power plant but not a bomb, Iran has signed the Nuclear Non-Proliferation Treaty under which it is given the inalienable right to civilian nuclear power but pledges not to pursue nuclear weapons, and the International Atomic Energy Agency has signed off on the whole program. What kind of bullshit is this!? This is not newsworthy and will only confuse people more about Iran. It's like saying that by living near the beach, I've amassed enough silicon to build my own computer from scratch (something I've thought would be cool to do for years: I want to start with raw materials and make a 2-function calculator or something). Except that when you get down to it, I'd still need to purify and dope the silicon, create transistors and then connect thousands of them in the right order to get anything close to the results I want. So, while it's technically true that I've got access to enough silicon, I'm actually still years away from results (and not actively working on it in the first place). It's a non-issue. It really irks me that the press picks up on this drivel while ignoring things like, say, the terrorist building a dirty bomb on US soil, which seems far more interesting, relevant, imminent, and dangerous (original source on page 11 of this leaked FBI document). Bruce Schneier suggests that this isn't pressworthy because the terrorist wasn't Muslim. Hooray, anti-Muslim bias in the media! To be fair, I've found three articles on Iran today whose headlines don't seem overly misleading: Reuters' Iran "not close" to nuclear weapon: Gates, Politico's Gates and Mullen disagree on Iran (which at least mentions that not everyone in government thinks Iran is getting a nuke tomorrow, though it does sow the seeds of doubt), and the Tehran Times' IAEA officials: All materials at Natanz under control (though honestly, no one is going to believe the Tehran Times if it's the minority dissenting voice about Iranian operations). and people wonder why I get so frustrated with the media. | | Sunday, February 22nd, 2009 | | 6:06 pm |
Will It Lens? Food Edition
If you missed it, here's part 1 and part 2 of our adventures with a 4'x3' fresnel lens. As always, I've got a gallery of all the raw pictures, and this is a summary of the good ones.
The same SAFETY NOTES as before apply, with the addition that you shouldn't eat any food you cooked in the same skillet in which you just cooked non-edible things (plastics, coins, etc). Also, we've upgraded our welding goggles, from a shade 5 filter to a shade 12, which is actually good enough that you can stare at stuff in the focal point. It's not quite good enough to stare directly at the sun, but it's darn close, and rumor has it that you can watch sunspots through this thing if you don't look at them too long. Last time, I left you with a picture of popcorn getting ready to be lensed. ( More results with more pictures )As always, remember safety first. Also, if you have more ideas of things we should try, I'm happy to give them a shot.  Edit: check out part 4 for more lensing fun! | | Friday, February 13th, 2009 | | 12:23 am |
Will It Lens? Part 2
In case you missed it, here's part 1 of our adventures with the 3'x4' fresnel lens. Oh, man. I have lots more pictures. The same SAFETY NOTE as last time applies again, but with a few more additions. You should probably wash your hands after you're done handling stuff in the lens. In particular, when you heat copper up until it turns black, you've probably made copper (II) oxide, which is a somewhat nasty irritant. I also make no guarantees about how many carcinogens we've made/touched/breathed, although so far I still feel healthy (no cancer in the past week!). Speaking of health hazards, if you use a frying pan to hold stuff, make sure it doesn't have a Teflon non-stick coating! That coating will burn away and become a huge safety hazard (it's mainly fluorine, and most fluorine compounds are toxic, volatile, and several other kinds of nasty; quite a few fluorine compounds were used as chemical weapons and precursors to sarin nerve gas, so avoid it at all costs). We got a cast-iron skillet, which is reasonably safe and inert, and it doesn't melt until we break 1800K, which is very unlikely with our current setup. Anyway, on to the results. ( with more pictures, of course. ) Until next time, make sure to have safety, fun and learning (in that order), and always remember that science is awesome! Edit: To find out what happens to the popcorn, check out part 3! |
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