?

Log in

No account? Create an account
Random Thoughts [entries|friends|calendar]
Kalina's Dad

[ userinfo | livejournal userinfo ]
[ calendar | livejournal calendar ]

Space, the final frontier [14 Jul 2009|12:46pm]
Elon Musk and SpaceX launched a satellite on their commercial rocket, yay:)
http://www.wired.com/wiredscience/2009/07/spacexlaunch/

Closer to home, the space elevator competition is in trouble. Ben Shelef of Spaceward says he needs another $66,000 to hold the competition; and he's trying to get it from the teams, or raise it through light-footed financial maneuvering. For now, test runs are still on schedule; but I've got a feeling more delays are on the way.
3 comments|post comment

DIY electrochemical machining [08 Jul 2009|01:04pm]
"It's called electrochemical machining (ECM), and it's so simple in principle that you can do it at home with a drill press, a battery charger and a pump for a garden fountain.

ECM is basically electroplating in reverse. In electroplating, you start with a solution of dissolved metal ions and run an electric current through the liquid between a positive electrode and the object you want to plate (the negative side). The ions deposit themselves as solid metal onto the surface of the object.

In ECM you start with plain water (lightly salted to make it conductive) and run the current in reverse, so you're turning solid metal on the piece you're machining into dissolved ions in the saltwater, wearing it away a tiny bit at a time. The shape of the electrode determines the pattern that results."


http://www.popsci.com/diy/article/2009-06/carve-steel-saltwater-electricity-and-tin-earring

This looks pretty cool. On the one hand it's slow and (in amateur versions) not that precise. On the other hand it could be the best way to make complex shapes from hard metal without heat treating or other major investment.
1 comment|post comment

Thunderstorm harvesting [01 Jul 2009|10:40pm]
There's a thunderstorm tonight; I can see the flashes of lightning through my window blinds. And it occurs to me that a good thunderstorm contains lots and lots of energy; and lightning concentrates that energy into a small area. There ought to be a good way to harness that energy and put it to use..

A capacitor that could catch a lightning bolt would be impractically large. Is there a way to pull the energy out in a slow, controlled manner.. (Ok yes, windmills, but I want something better)
4 comments|post comment

What it's like being a geek [28 Jun 2009|10:23am]
http://xkcd.com/602/
post comment

Darn elves in diapers [26 Jun 2009|12:38pm]
"Doctors Baffled, Intrigued by Girl Who Doesn't Age
Years Pass, but Brooke Greenberg Remains a Toddler. No One Can Explain How or Why.
"

http://abcnews.go.com/print?id=7880954
2 comments|post comment

Dryer again [24 Jun 2009|04:27pm]
I fixed my dryer today. It last broke a year and a half ago, so I suppose that's not too bad for a ~fifteen-year-old appliance.

http://tevarin.livejournal.com/2008/01/21/


Nearly the same problem, too. Break in the heating element. I wonder if electrical spikes might be causing the breaks, or excessive vibration...?

This time it happened right next to the contact terminal, so instead of buying a whole new element, I crimped a piece of sheet copper to form a new terminal, and soldered it together with high-temp aluminum solder to make a good connection. I figure I'll keep an eye on it for the next few loads just in case.
post comment

Teachers should minimize busywork [11 Jun 2009|04:09am]
"Student challenges prof, wins right to post source code he wrote for course"

http://www.boingboing.net/2009/06/11/student-challenges-p.html

The student is right, of course. But I think Cory Doctorow makes an even more interesting larger point:

"I've always thought it was miserable that we take the supposed best and brightest in society, charge them up to $60,000 a year in fees, then put them to work for four years on producing busywork that no one -- not them, not their profs, not other scholars -- actually wants to read. Might as well get them to spend four years carving detailed models of ships from sweet potatoes (and then bury the potatoes)."

How do you design student assignments so that they not only promote student learning and allow easy grading, but also have external value? Is it worth some sacrifice to the first two objectives in order to benefit the third?
4 comments|post comment

Not just an excuse to link to topless pictures of women [11 Jun 2009|12:21am]
"Breastlight, a device produced by PWB Health Ltd out of Dumbarton, UK, was developed by Highland Innovation Centre (Inverness , UK) to help women spot suspicious breast lumps in the privacy of the home. By shining light of specific frequencies that best penetrates breast tissue, it should be possible to locate darker, and therefore denser spots for further review by a physician."

http://www.medgadget.com/archives/2009/06/breastlight_helps_augment_athome_self_exams_1.html

I want one of these. If it will shine that much light through a breast, you could probably get cool views through hands, feet, etc. as well. Safer and far cheaper than an X-ray or MRI.
3 comments|post comment

The world of chemistry [09 Jun 2009|01:06pm]
http://www.youtube.com/watch?v=a45dXztokZM&eurl=http%3A%2F%2Fandrewsullivan.theatlantic.com%2F&feature=player_embedded
post comment

Balloons...in...Space [08 Jun 2009|04:30pm]
"A GIANT inflatable tower could carry people to the edge of space without the need for a rocket, and could be completed much sooner than a cable-based space elevator, its proponents claim.

Inflatable pneumatic modules already used in some spacecraft could be assembled into a 15-kilometre-high tower, say Brendan Quine, Raj Seth and George Zhu at York University in Toronto, Canada, writing in Acta Astronautica (DOI: 10.1016/j.actaastro.2009.02.018). If built from a suitable mountain top it could reach an altitude of around 20 kilometres, where it could be used for atmospheric research, tourism, telecoms or launching spacecraft.
"


http://www.newscientist.com/article/mg20227117.000-inflatable-tower-could-climb-to-the-edge-of-space.html

20 km altitude is a small step towards space in terms of required energy to reach orbit, but it would let rockets avoid almost all of that annoyingly thick, drag-inducing atmosphere. Atmospheric drag is worst for relatively small rockets. Micro-satellite launches in particular might be easier from the top of an inflatable tower rather than from ground level.


On the other hand, weather balloons and airplanes can reach 15 km much more cheaply, so unless you've got a *lot* of microsatellites to launch, the inflatable tower may not be the easiest way to go.

It would make a heck of a telecommunications/surveillance platform, though.
post comment

Robogames [08 Jun 2009|01:29pm]
"The event will host over 70 different competitions, including 18 different events just for walking humanoids. Large scale combat robots will fight to the death behind bulletproof glass, thrilling the crowd with crashing, smashing, flame-throwing, and miscellaneous wanton destruction. The combat robots, weighing as much as 340 pounds, are what draws most people to the event, but many stay for the AI based sumo robots, soccer bots, and kinetic art that fills out the venue.

But that's not all - other events include kung-fu humanoids, hockey bots, fire fighting competitions, autonomous explorer bots (like the Mars Rovers!), art bots, bartending robots, and mechanical marvels that defy description! The newest event is "Mech Warfare." Humanoid robots with bb cannons and rockets with try to take each other down, while the pilots control them remotely via in-robot cameras, with no look at the field from above.
"

http://www.boingboing.net/2009/06/08/robogames-worlds-lar.html


This looks pretty darn cool. Maybe next year I'd have the money and time to go check it out. I wonder if they've got significant prizes?
post comment

Turn around, bright eyes [30 May 2009|12:25am]
http://www.youtube.com/watch?v=lj-x9ygQEGA&eurl=http%3A%2F%2Fandrewsullivan.theatlantic.com%2F&feature=player_embedded

(Lyrics slightly NSFW)
1 comment|post comment

North Korea, Iran, and Nuclear Weapons [26 May 2009|03:49pm]
"SEOUL, South Korea – North Korea defied world powers and carried out an underground test Monday of a nuclear bomb Russian officials said was comparable to those that obliterated Hiroshima and Nagasaki. The incident drew condemnation from Washington to Beijing and set the communist regime up for a showdown with the United Nations."

http://news.yahoo.com/s/ap/20090525/ap_on_re_as/as_koreas_nuclear

Why does North Korea have nukes and Iran doesn't? Iran has a larger population, and far more money. In the past thirty years Iran's lost far more soldiers in combat.

Iranians aren't dumb. There's a long tradition of Persian excellence in science. One of my best engineering professors at UF was Iranian. And granted that Islamic fundamentalist authoritarianism isn't the best environment for research, is it really that much worse than dynastic Stalinist paranoia coupled with mass starvation?

Either the West is much better at sabotaging Iranian nuclear weapons work than Korean work, or Ahmedinejad et al. don't really want nukes that much. Which may be cause for hope. At least until the North Koreans hang out their "will trade nuclear warheads for food" sign.
2 comments|post comment

Can you regain lactose tolerance? [25 May 2009|12:47am]
Two weeks ago, when I was making ice cream with my physics classes, I ended up sitting in the office grading papers late one evening, terribly hungry, all the on-campus eateries closed for the night, with nothing in the office fridge but whole milk and hershey's syrup from my ice cream experiment. So I had three large glasses of chocolate milk for dinner.

And I expected this to bother my digestive system, but I was so hungry I didn't care.

And my stomach, etc. turned out to be fine with it. Which is weird, because over the past few years, every time I've had more than one serving of milk or ice cream at a time, I've regretted it. I wonder if I've got a better internal bacteria population these days, or what.
6 comments|post comment

Everything is alive? [21 May 2009|12:23pm]
"When I look at a stone, I think of ten octillion balls connected by springs. There’s a lot going on in a rock, enough to support universal computation, enough to run a mind."

http://www.boingboing.net/2009/05/21/everything-is-alive.html

I thought this was interesting. I'd agree, you could store huge amounts of information in crystal defects, grain boundaries, etc. And there's at least a little available energy from thermal gradients, diffusion gradients, etc. I can imagine an ecosystem of Game-of-Life style automata, made up of crystal defect patterns. You can make a Turing computer with cellular automata.

But just because it could happen in theory doesn't mean it really does happen. How would we detect such small-scale life? Way too small and subtle to show up in an optical microscope. Maybe an atomic force microscope to see the suckers move, or x-ray crystallography to detect fields of oddly crystalline, energy harvesting, self-replicating "plants" deep within a boulder.
2 comments|post comment

XKCD:) [18 May 2009|09:50am]
A wonderful thing about science, too often ignored in science classes, is the chance that experimental results will not merely confirm an established theory, but will generate something new, not predicted or expected.

http://xkcd.com/585/
post comment

happy post [09 May 2009|09:40pm]
http://www.youtube.com/watch?v=UXPJJeISuXo&eurl=http%3A%2F%2Fandrewsullivan.theatlantic.com%2F&feature=player_embedded

With thanks to andrewsullivan.com
post comment

Be sure to keep your maps up to date [02 May 2009|01:12am]
http://www.boingboing.net/2009/05/01/artwerks-map-of-his.html
post comment

Pi (the movie) [02 May 2009|12:04am]
I finally saw Pi this evening. Feelings are mixed.

slightly jumbled review, includes possible spoilersCollapse )

Net rating: 7/10. If you want a movie about the underlying mathematical nature of the universe, see Contact* or Donald in Mathmagic Land. If you want a movie about an insane genius mathematician, See A Beautiful Mind. If you've already seen those, and want something more edgy, more Jewish, and less polished in terms of cinematography, give Pi a try.

*The book is even better
post comment

Teach your kids about H1N1 [01 May 2009|06:39pm]
(link has slight profanity)

http://www.boingboing.net/2009/05/01/et-tu-pooh.html
post comment

navigation
[ viewing | 20 entries back ]
[ go | earlier/later ]