Christopher Thomas' Journal

Simulations, Lack of Dojo, Lack of Board, and Atoms

Finished simulations for several stripped-down models of the test board. These reproduce the problem, confirming that it's resonance modes in the board's ground plane. Fixing the problem is proving a lot more difficult. The best it looks like I can do with the existing board is push the artifacts up to about twice the frequency (I need more like 20x). I'm thinking over the design of a new board, but I still need to confirm (by simulation) that it'll work as intended. I *might* be able to check this by modifying the existing board (we'll see).

Didn't, however, get a new board designed and ordered today (despite cancelling dojo). This means the earliest a new board would arrive is Monday, which is almost certainly too late if I have to send the test equipment back this month. I'll know for sure later in the week (if I get an extra month, and have a design I can prove will work, no problems).
Subway project for the day: making up rules for building fake atoms on a grid of graph paper. Real atoms exhibit very complex behavior stemming from a small number of simple rules (simple to write, not simple to solve). This got me thinking about how you'd set up "toy" systems on graph paper that behaved in vaguely similar ways. Result: I'm getting shells at discrete energy levels, and I'm still investigating what happens when you try to form molecules. Several variants of the rules are still under consideration. Definitely a fun diversion.

Now, slacking and bed.

Current Mood: stressed
Current Music: "Buoy Base" ambient music (Super Mario Galaxy)

Lack of Work, and Speed of Sound

Got almost nothing done at work. This more or less confirms that if I end up working through a weekend, I end up taking days off to compensate even if I go into work. Not so good, given that I still don't know if I'll get an extension on use of the test equipment.
Did finish setting up the simulation of the experiment board. This will be tested tomorrow. It's not a complete simulation, but it should still give me artifacts similar to what I've been seeing if my guess about the cause of the artifacts is correct.

I'm also slowly figuring out what a revised test board will have to look like. If I submit a design for one tomorrow, I'll have it in-hand on Friday, which is probably too late but might still be worth trying. I might also be able to re-work the existing board, but that'll involve a lot more dremel work than originally planned (though it may be possible for me to cheat). I still need to think about this before committing to a course of action.
Subway distraction for the last little while: computing the speed of sound from first principles. While you can easily figure it out approximately for a gas (average speed of a gas molecule), deriving it for a solid was a bit trickier. It turns out to be simple to calculate, though: sqrt(Y/rho), where Y is the elastic modulus, and rho is density.

Of course, after doing this, I found out where to look it up. Getting there is still have the fun, I guess.

Mostly I did this to see what time steps I'd have to use for mechanical simulations of solids and liquids. While the nominal speeds at which things are moving are much lower, all disturbances still propagate at the speed of sound (this is how distant parts of an object learn what forces are being applied to the point of contact).

Now, slacking and bed.

Current Mood: headache
Current Music: "What do you do with a drunken sailor?"

Hike, Lunch, and York Slog

Dojo event happened. This involved hiking through a scenic part of the Niagara Escarpment. At the top, the instructors had a meeting (seminar plus drills), and the candidates going for black belt had to do katas, all in rain, waist-high grass on uneven ground, and mosquitos.

This was actually quite pleasant, overall. The rain was light, but still enough to keep the bugs down for most of the hike. I was dressed properly for hiking in mud, and the scenery was wonderful.
Lunch happened. Once again, it was just myself and Bryan. This was still a decent opportunity to relax and to catch up. I've also received another birthday present (DVD of Yellow Submarine), in addition to the one Marc gave me yesterday (a sketchbook with printed circuit board covers).
York happened. I didn't get as much done as I'd have liked, but I did get most of the setup done for simulations of the problem that's happening. I also have a slightly better understanding of how to calculate the parameter values needed for the simulation (the easy way of calculating stripline capacitance and impedence is off by about a factor of 3-10).
Yerf archiving is still chugging away. 17k images and 13k thumbnails acquired, out of a nominal 26k of each. The script is also checking for and retrying single-pixel images, which are sometimes returned by archive.org instead of the real thing (original 4000-picture run had at least 1000 of these in it).

Now, slacking and bed.

Current Mood: sleepy
Current Music: Starcraft (Terran theme)

Testing Shennanigans, Return Party, and VP Slack

Went into York, albeit for less time than I'd planned. Tests showed that the problem does _not_ result from case modes, which means it's either from the traces themselves, or from the traces exciting resonance modes in the shielding plane (which is grounded, but with nonzero propagation time). Shielding plane is my best guess, but I'm going to make a simulated model of the traces regardless, so that I can see if they're causing any of the other artifacts I'm seeing.

Testing the shielding plane guess will need either an exacto knife and a lot of patience, or a dremel tool and a steady hand. I'm going to have to _find_ that dremel tool.
Made to lastmx's back-in-Canada party. Had time to chat with him and with other early-arriving guests before heading out. Building a solar furnace is his present mad-science project idea. I'd have loved to help out 10 years ago, but I'm short on both time and money at the moment, so information/advice is the best I can do.
Made it to the VP Crew in time to contribute snacks and boardgames. Half of the group played Rock Band upstairs, and the rest retreated to the basement to play games. Fun occurred for all (and I finally got a chance to sing the "Still Annoyed" filk to "Still Alive" on Rock Band). Left early enough that I won't be a complete zombie for tomorrow's hike.
Plan for Sunday: Get up very early. Drive to the dojo with hiking gear, rain gear, and a change of clothes for post-hike. Survive the hike/instructor meeting. Get back in town, take transit downtown for lunch (hopefully with non-soaked clothes). Enjoy lunch. Transit back to the dojo, pick up the car. Drive to York to do more board tests. Drive home without falling asleep.

Plan for Monday is continued testing-slog.

Now, puttering and bed.

Current Mood: grumpy
Current Music: Brinstar Theme (Metroid 1, Metroid Metal cover)

Experiment Ugliness, Assisting, and Image Indexing

More experiment data has been plotted, and the results aren't good. The case for the microwave tests has resonance modes, and the microstrip waveguides act as antennae; together, this means the different signal lines couple strongly to each other with a cross-talk spectrum that looks like a series of spikes and notches at moderate frequencies, and like a chaotic mess at high frequencies (it's a comb, but I'm undersampling it and so getting random values). The cross-talk is noisy enough to swamp the signal data in the areas I'm interested in.

I'll be at York over the weekend looking into solution options. The best approach so far is to put a sheet of paper over the board and stuff the case with tinfoil (imperfect, but it might work adequately). We'll see how this goes.
Assisting happened. Assisting went adequately. Kobudo class happened. Kobudo class also went adequately, mostly because the only people I had to deal with were the candidates (one other student had a private grading-rec with Sempai, and the rest of the regulars are probably on holidays). The candidates are progressing fairly well, though there's still a lot of work to do.
The Yerf image archive no longer has a robots.txt file, so spidering of the archive.org copy of it has resumed. Based on what I have so far, this will wind down by Monday (just shy of 30k images on the site, more like 50k including thumbnails, maybe half accessible, and I got to about 4k over maybe half a day last time). The script has been modified to skip images it's already checked for, so resuming is no problem. I can even have it check multiple versions of the artist database for artists who have been added (checking newer copies) or removed (checking older copies).

Distributing any of this would be a big no-no. I'm mostly doing this for the sake of nostalgia, and to satisfy my inner data-packrat. The archive will collect dust on my hard drive next to the Wikipedia database dumps.
Plan for Satuday is sleeping in, then York, then Marc's party, then VP-slack. Plan for Sunday is getting up way too early for a dojo event, then group lunch, then more York. Plan for Monday and onwards is a deadline crunch for experiment data, assuming I can get useful data at all.

Now, puttering and bed.

Current Mood: chipper
Current Music: Bohemian Rhapsody (Queen)

Experiment Slog, and Lack of Images

Made incremental progress on the experiment, helped by skipping dojo, again. If I'd thought about this, I'd have gotten coverage to skip Friday as well. As-is, I may have to come in for part of the weekend (which will be annoying, but probably a good idea).

Long story short, some, but not all, of my calibration data is repeatable. There are parts of the measurement region that are just plain ill-behaved, and I don't have the time or equipment needed to do a really good job of calibrating it (I'd need to have computer control of the spectrum analyzer working and be familiar with it, or I'd need to spend a full week doing calibration by hand). The workaround is to put the noise floor 20 dB higher, which would more or less happen even with good calibration (perfect calibration gives me an extra 10 dB in about half of the area, but imperfect calibration isn't trustworthy).

Further plotting of already-collected data happens Friday. Based on that, I decide if I need to take more calibration measurements or not. If I do, it's weekend-slog time.
At long last, Yerf is back up (as a skeleton, for now). The downside is, it has a robots.txt file that prevents spiders (like the Wayback Machine) from crawling it.

The problem: The Wayback Machine checks to see if the file exists on the _current_ version of the site, before accessing saved _past_ versions. Yerf came back at *exactly* the right time to stall my image-crawling script. As near as I can tell, this is just dumb luck (of the bad kind), but it means that the images that used to be on Yerf are lost again (for now). I'm kicking myself for not writing the crawler-script years ago.

Now, slacking and bed.

Current Mood: aggravated
Current Music: none

Testing Milestone and Old Art

Finished the first round of tests at York. The good news is, this gives me a reasonably good idea of how the test board is behaving without a chip in it. The bad news is, test data indicates that I need to spend an extra day getting higher-resolution numbers for part of the transfer function. This is doable (it just means I'll be busy until the end of next week with the real tests instead of the middle).
Finally got around to a project I'd backburnered years ago: Crawing the Wayback Machine for images from the Yerf archive. In a nutshell, the archive was much-loved, crashed due to drive failure, and failed to get restarted despite large amounts of help and money offered (mostly due to actions of the admin). Shortly after the crash, I'd crawled archive.org to get database information without images (just name and description info for each of them), which were sent off to the admin. However, with the site staying dead, looking for image backups became attractive. The Wayback Machine doesn't have all of them (or even most of them, it seems), but it does have enough to make an automated crawling worthwhile.

I now have a script that does this. Writing it was both fun and satisfying. It should wind down by tomorrow morning.

Now, bed.

Current Mood: accomplished
Current Music: Final Fantasy IV soundtrack

Incremental Testing, Submarine Chemistry, and Weapons

Made incremental progress on the calibration tests for the experiment. These are still on schedule to be finished tomorrow. The transfer function is looking even nastier than I'd thought, but I should still be able to get useful data with the calibration I'm doing now. Fallback plan, if necessary, is to spend an extra day on calibration to be Really Sure I have all of the artifacts in the transfer function.
Subway amusement is still making submarine plans. The form is more or less nailed down, though I still need the correct equations for speedboat stepping lift. In the meantime, I've moved on to working through the engine and chemical plant system. This will work sort of like a fuel cell, but without being electrical. Ammonia is stored as a pressurized liquid, and oxygen as a cryogenic liquid. These are burned in a turbine for mechanical and electrical power. The exhaust is chilled, with water (tained with unburned ammonia and partial combustion products like hydrazine) stored as a liquid, and nitrogen stored as a cryogenic liquid. Upside: no exhaust bubbles, and easier regeneration of fuel during recharge (no need to purify air and saltwater). Downside: one hell of a lot of heat sinking is required (meaning a large cooling loop has to penetrate the pressure hull). The silver lining is that this could let you use an enclosed water-jet scheme instead of a propeller (though this doesn't really gain you much).
Dojo topic was weapons. Was shown the last weapons kata I needed at this belt level. Now, I just have to write it down before I forget it (this has happened in the past).

Now, slacking, Stargate, sewing, and bed.

Current Mood: drained
Current Music: Duck Tales theme

Experiment Progress and Submarine Confusion

Started the experiment I've been putting off. Data collection is taking a while, but not as long as I'd feared. I should have calibration info for the test board without a chip by the end of Wednesday, and chip data in-hand by the end of Monday or Tuesday, barring further delays. I'm seeing lots of artifacts in the calibration data, but they're mostly ones I was expecting. Net result is to confirm that calibration is a Good Idea and definitely needed if I want useful results.
Still poking at numbers for a submarine. The main thing that's confusing me now is the hydroplaning surfaces. There are two ways to get a lift-to-drag ratio from first principles, and they give very different answers. Checking online to find the Right Way has mostly resulted in confusion. This is complicated by the fact that I'm trying to work numbers for something more like speedboat stepping than an airplane wing. I'm also in the boundary layer, where the simple equations stop working, and I'm almost certainly in turbulent flow, where the simple equations stop working. This has "build a model and test it" written all over it. Still fun, for the time being.

Now, puttering and bed.

Current Mood: confused
Current Music: Tech Gain Music (Master of Orion)

Lunch, Kites, Submarines, and Incremental Sewing

Lunch happened. Lunch was decent, though it was just myself and Bryan this week.
Met up with Flan for kite-flying. This too was decent, though I got a sunburn (hat and sunblock would have been wise; pity I didn't bring them). We've more or less caught up with each other, though any plans for future meetings remain vague.
Made incremental progress sewing my brother's birthday gift. This probably won't get done tonight, which means I mail the primary gift Monday and the secondary gift when it's done. This is what I should have done two weeks ago. Hindsight, etc.
Thought experiment for the last couple of days: building a submarine. This was insprited by dracosphynx's recent post, which included a link to a site with a very detailed description of a WW II submarine. The idea behind my thought experiment is to work through the design of a recreational submarine made using "ferroboat" techniques (making the hull out of reinforced concrete). A top-level analysis says this is feasible, with an estimated cost of $100k for a full-sized (albeit small) submarine capable of diving to 300 feet, moving on the surface like a boat, or "sprinting" on the surface like a speedboat (at the cost of much shorter range). A 1/4-scale prototype would cost about $2000; this prototype has been added to the "to make someday" project list (aka the "don't hold your breath" list). I'm poking at more detailed designs, though I'll likely move on to other thought experiments soon enough.

Now, puttering and bed.

Current Mood: sleepy
Current Music: Ending Credits Theme (Sonic and Knuckles)

RPG Milestone, Tower Defense, VP Slack, and Motors

RPG day happened. RPG day was decent. Got enough NPC help to pull off the rescue that had been causing planning problems last session, and we're on track to get back onto the plot rails with the invading army.

Introduced the RPG group to Desktop Tower Defense. Tony and John are now potentially new addicts (Bryan already knew about it, I think).
VP slack happened. VP slack was decent, though I got there late enough to not have a spot in the Rock Band. Next Saturday is not an RPG day, so I can arrive earlier.
Finished yesterday's subway diversion (working numbers for conventional electric motors). Very tiny motors based on a rotor coil and a stator coil can be built, and work, but scale poorly (bigger ones work _better_, from what I can tell). The main problem with making these using "desktop lithography" is that implementing them needs feature sizes more along the lines of chip lithography. This is because sheet current in the motors is very large. Moving to a lower current, higher voltage scheme requires lots of windings in a small space, and so high spatial resolution. Doing this as a series of low-resolution thin layers works for the stator, but not the rotor (which has more than one coil plane). Ditto with induction motors (which have a different control scheme but the same numbers).
Plan for Sunday is lunch, kites, and then working on my brother's late birthday gift.

Now, slacking and bed.

Current Mood: sleepy
Current Music: Main Deck theme (Metroid Fusion)

Homework Milestone, Testing, Assisting, and Cake

Finished the last parts of the assignment I was working on over the week. There's now only one assignment left. Unfortunately, it's getting put on the backburner so that I can be sure to finish the microwave-frequency tests before I have to send the equipment back. This is sub-optimal, but necessary.
Additional amusement from yesterday: Converting and debugging a sponge cake recipe from the future (it should use 200g self-rising flour, rather than 100g). Naturally, this will have to be checked by experiment. Very tasty experiment.
Assisted without incident. Ran the weapons class without major incident (went overtime enough to get told not to go overtime, but that was it). Balancing dojo and work for the summer and fall will be tricky, but should be survivable.
In theory, game day and kites are on for Saturday and Sunday. No response re. lunch, so it may just end up being myself and Bryan; we'll see.

Now, puttering, slacking, and bed.

Current Mood: sleepy
Current Music: Starcraft (Terran theme)

Homework, Lack of Dojo, Tower Defense, and Weekend

Took the day off from dojo, and spent it at work. This was a Good Thing, because I still haven't finished the first of the two assignments. I did get 5 of the 6 remaining articles processed, so finishing it tomorrow shouldn't be a serious problem.

The serious problem will be re-reading all of the course readings and posting both my own responses, and responses to others' responses, for the second assignment. I did a very small amount of this during the term. Moral of the story: Trying to handle a deadline crunch by delaying schoolwork ended up delaying both the schoolwork, and the deadline I was crunching on. Not so good.
Subway distraction for the day: Working through the math governing Tower Defense rulesets. This gave some surprising results (how important range is depends strongly on the length and spacing of creep bursts). The version I first played was Flash Element TD, and the version I'm playing now is Desktop TD.
Friday is a York/Dojo day as usual. Dojo is mandatory, because I didn't phone around for coverage (so I'm on the hook for assisting and instructing). I'll get the first assignment done, and pack material for the second after taking a stab at the first parts of it. Saturday is game day, followed by VP slack. Sunday was going to be kite-flying with Flan, but is now supposed to be a day of rain, so I'll probably go with the normal lunch plan. Sunday afternoon will involve coursework, mostly.
Still haven't finished the second part of my brother's increasingly late birthday present. Also have to draw up a card for another friend's birthday, which I've been meaning to do for at least two years previously. Also still have to dust off LED board code for Prof. T., and I have tests that need to be done at York before the test equipment gets returned at the end of the month. Both this weekend and next week will be very busy.

Now, puttering and bed.

Current Mood: stressed
Current Music: "Level Debriefing" music (Command and Conquer 1)

Incremental Homework and Semi-MEMS

Made progress on the first of the two homework projects. In theory, I have what I need to hand it in now, but I'm finishing off one last piece before calling it done. We'll see how much more time this eats.

If necessary, I'll cancel dojo for tomorrow. This is probably a good idea, as it'll let me start on the second project.
Subway thoughts for the day: using printed circuit board etching techniques to make MEMS-type structures. Long story short, it'd work, but there would be problems and limitations. Main problem in implementation is that it's very fiddly (I'd need to make equipment that looks a lot like an IC foundry, only not nearly as difficult/expensive), and the main problem in application is that I'd still need to add motors and electronic components by hand. So, the gain from fabricating things in parallel is offset by the parts I still have to do in series. Making thin-film electronics involves _much_ more difficulty/expense, and making MEMS-type motors doesn't work very well at a macro-scale (after running numbers, I'm surprised it even works at a MEMS scale). Making ordinary motors _might_ be possible, but would take enough layers to be a royal pain to fabricate. We'll see.

Now, Stargate and bed.

Current Mood: sleepy
Current Music: "The Happy Birthday Song" (Arrogant Worms)

Incremental Homework, Robots, and Assisting

Made more progress on the homework assignment. Didn't finish it, but I now have the papers in-hand that I need to write about for the rest of the bibliography. It should be possible to finish this on Wednesday (a non-dojo day, so I'll have a longer time at the university). After that, only one more assignment remains.
Subway project for the day: mechanisms for very small robots. The idea is to use as few motors as possible, as they're bulky. The item that needs the most degrees of freedom, by far, is a "manipulator" (generally an arm with a claw at the end, but could be a number of things). This is very difficult to avoid, as you need to be able to position it with 3 degrees of freedom, orient it with 3 degrees of freedom, and open/close it with at least 1 degree of freedom for it to be a really useful tool. There are ways the number of degrees could be reduced, but they have their own problems.

The Good Way to build these is to put motors in the arm itself, with one motor per degree of freedom, and very simple coupling between the motor and the joint it actuates. The Normal Way to build this is to have most or all of the motors in the shoulder, with a complicated series of belts/chains/gears transmitting it to the various parts of the arm and hand. I worked through most of the gearing and chaining system for one of these today, and it's definitely sub-optimal. The advantage, though, is that if I set things up right in the shoulder, I can get away with using only two motors: one to deliver power to the selected joint, and one to select between joints being moved. The rest stay locked in position. As long as I don't _need_ to move more than one at a time to perform an operation, this works (at the cost of taking longer to do most things).
Assistants meeting happened. Assistants meeting went adequately, though I'm going to be stuck with the weapons class for at least 4 months, and probably 8. I enjoy working with the students quite a lot, but I'd really like to be able to spend Fridays in the lab instead of at the dojo. 8 months is problematic, because I'd get Fridays back right _after_ I need them (chip crunch will be Sept. through Jan.). We'll see how this goes.

Now, Stargate, slacking, and bed.

Current Mood: sleepy
Current Music: Space Pirate Music (Metroid Prime)

Birthday Slack, Incremental Homework, and Fusion

Spent Sunday doing more birthday-slacking (so, no homework progress then either). Lunch happened, with a nice turnout. After that was a bit of wandering around downtown chatting (while looking for metal casting supplies), followed by bookstore-slacking. I've now read "Making Money", which I enjoyed quite a bit.
Monday was a homework day. Made progress on one of the two remaining assignments. In theory, I can finish this tomorrow; we'll see what happens in practice.
Got bored with mirror equations, so I moved on to working numbers for how big a block of deuterium ice, heavy water ice, or lithium deuteride you'd need in order for a runaway reaction to be self-sustaining. I'd run these numbers before, but this time around I did it a bit more thoroughly. It turns out that the minimum size is small enough to be almost practical (1 metre for frozen deuterium, 3 metres for lithium deuteride, 6 metres for heavy water ice). The problem is delivering the initial impulse. The block in question needs to be heated to about 160 million degrees kelvin (15 keV). If you can fit a 30 kT nuclear warhead into 1 cubic foot, you can detonate the frozen deuterium; otherwise, scaling starts to bite you (power per unit volume can be reduced by using a bigger block and heating a thin shell, but absolute power needed still goes up quite fast).

From what I can tell, the requirements for lithium deuteride are _almost_ reasonable enough to be a viable way to make a fusion bomb. Based on the fact that nobody's done this, I'm guessing the problem is in the "almost" part. Conventional fusion bombs compress the lithium deuteride, which makes containment much easier (minimum radius goes down inversely with density going up).
Also started thinking about metal casting more. Most small items I'd be interested in making would cost $1-$5 to make, with Digikey's prices for lead-free solder. This is still attractive enough to be worth doing.
Plan for Tuesday is homework, then assistants meeting. Plan for the rest of the week is the other homework project.

Now, Stargate, slacking, and bed.

Current Mood: sleepy
Current Music: Sector 5 Revisited (Metroid Fusion)

Mekton Slack and Party Slack

Finished the Mekton Zeta character generation utility. The CGI script is here. This rolls on all of the random tables in the book to produce a character lifepath, NPC descriptions, and events during work terms.
Party happened. Party was decent. Rock Band was more fun than I thought it'd be, mostly due to "Still Alive" being one of the songs available. Also persuaded the group to play Diplomacy, though this was cut short before the game finished. The setting worked reasonably well; it was a "comp stomp", with me taking Russia, Turkey, and Austria-Hungary, and the rest of the players working to defeat me. Things worked as intended, and they started with enough of an edge to be winning by the time the game wound down.
Lunch for Sunday is on, with a larger turnout than usual. Shireen, her SO, and her SO's kids will be there, as will my parents, so it should be quite nice.
Other plans for Sunday: Going to a planting event at High Park in the morning, and finishing my brother's birthday gift in the afternoon. Homework is theoretically on the list somewhere.

Now, bed.

Current Mood: exhausted
Current Music: Lobster Sticks to Magnet

Lack of Homework, Partial Paper, Tower Defense, Assisting, Math, and Birthday

Slept in rather than getting to York early enough for the morning's image sensor seminar. Still scavenged leftovers (this week has been "free food for grad students" week, due to all of the seminars with catering). The topic was high-sensitivity CMOS image sensors. It turns out that this sensor was based on an array of avalanche photodiodes (diodes held over the breakdown threshold, with the breakdown "avalanche" triggered by single photons of light). This is a well-known technique, but this author managed to produce another incremental refinement of the device, on a conventional CMOS fabrication line. So, reasonably nifty.
Didn't get any useful homework done. Brought the homework materials home to continue working over the weekend in my Copious Free Time(tm).
Cleared Desktop Tower Defense on the "3k gold challenge" mode. Still having trouble with the "10k gold fun" mode and the "1.5x health hard" mode.
Still working through magnetic mirror calculations. Still having fun, though I'll probably move on to other diversions fairly soon.
Birthday plans are still a go, and still relatively low-key. In short, it'll be the usual "slack with VP crew" and "lunch on Sunday" plans, but with candles and cake. This should be nice and relaxing, which will be a pleasant change from the last couple of weeks.

Now, slacking and bed.

Update [1:35am]:

The Mekton Zeta lifepath generator works, and can be called as a CGI script from the web. Next up is filling in all of the data tables (this will take a while).

Now, bed.

Current Mood: restless
Current Music: The Llama Song

Marginal Presentation, Incremental Homework, Birthday, and Fusion

Birthday venue has been confirmed. So far only one extra attendee, though I'm still pinging people.
Presentation at York happened. This went decently, despite me not having time to prepare figures for the slides. As a result, it was text slides/handouts, and whiteboard diagrams. This worked decently. I may put it online later. Long story short, my best advice for designing high-frequency boards is "don't, if possible". Many problems, and solutions tend to be imperfect.
Submitted a revision of the teaching philosophy document. This means my only remaining homework items are the responses to readings and the annotated bibliography. Both of these will take massive amounts of time. The bibliography will get stated tomorrow. Both will hopefully have progress made on them over the weekend. I'd really rather not have to deal with them past this week, but I'd also really like to pass the course.
Started going over calculations for Bussard's fusion idea again. Once you sort through the shady language in the claims, it ends up being a variant of the Farnsworth Fusor (an electrostatic confinement fusion device), that works by magnetically confining an electron plasma to perform electrostatic confinement, instead of using electrodes within the plasma itself. Both have been vastly over-hyped by proponents, but the Farnsworth machine produces enough fusion to be a useful neutron source, and the Bussard "polywell" device is pretty nifty in its implementation. I just don't buy the "power scales as the 7th power of size" claim (it's typically a much lower power), and Bussard's claims of this actually being useful for fusion power hinge on using the 7th-power rule to extrapolate from a "measured a handful of atoms fusing" machine to a "commercial power plant" machine. Doing the calculations myself would let me derive my own scaling rules for it.

So far, I've just been working the equations for magnetic mirrors, but this too is a fun exercise.

Now, laundry and bed.

Current Mood: sleepy
Current Music: Space Pirate Theme (Metroid Prime)

Incremental Work, Incremental Mekton, and Party Plans

Made very minor progress on homework. This needs to be drastically improved, ASAP.
Made incremental progress on the (informal) talk I'm supposed to give tomorrow at lunch time. I'll probably have an outline by then, but not slides with figures. So, it'll be a whiteboard talk.
Continued running numbers for destroyer-scale weapons in a giant robot, under the Mekton system. For aggregate firepower per unit cost, you're better off just using robot-scale weapons. This is even true factoring in range (it costs less to boost robot weapons to corvette-weapon ranges than to use corvette-scale weapons). Where corvette-scale weapons win is ability to deliver enough damage to swamp armour protection. Doing the same at robot scale requires using armour-piercing shells and several linked guns, which ends up costing about double what the equivalent corvette-scale weapon costs. So, an interesting tradeoff. This also explains why "close-in defense systems" are popular (small guns to shoot at small targets, big guns for hard targets).
The next game day conflicts with my first choice for birthday party days. So, I'm attempting to hold my birthday party this Saturday, with the usual Sunday lunch trip being the fallback option if this falls through, or an alternate venue for people who can't make Satuday. We'll see how this goes. I still haven't confirmed that Saturday is doable, and I still have to contact guests to see who can show up. I have about a week's less notice than I'd have liked. But, things should work out.

Now, puttering and bed.

Current Mood: sleepy
Current Music: "Cucumber Club" childrens' show theme