Sunday, June 29, 2008

Keep women away from stairs!

I have summarized for your convenience the top 7 consumer killers in the United States in the year 2001, and swimming pools, for comparison.  I think the conclusion here is inescapable: women must be kept away from stairs. This is a significant issue for me because I live in a house with two stories and a basement, with my wife and three daughters. Although the statistics presented are not specific, it does appear that the problem is largely with older women, so we'll definitely have my mother in law stay in the downstairs bedroom.

As I write this my two older girls are directly behind me, messing around in the crib that we generally use for our youngest. A quick check shows that I should escort them outside where they can safely fool around in traffic on some ATVs!

total deathsmale accidentsfemale accidentscategory
2021047671421274004Stairs, Ramps, Landings, Floors
45964248445 291530Beds, Mattresses, Pillows
30271203930 252960Chairs, Sofas, Sofa beds
25023125312 168238Bathroom structures and fixtures
24750414008 151660Bicycles
21239169834 38022ATVs, Mopeds, Minibikes
19085150667 72498Ladders, Stools
53228886472894Swimming Pools, Equipment

Wednesday, June 25, 2008

CO2 sequestration -- size of the kill zone

Sometimes, the underground reservoirs that store natural gas explode. Drilling wells into them makes this more likely. When wells explode, the gas generally ignites, making a spectacular flame that can be seen for miles. Aside from the loss of valuable fuel and equipment damage, well explosions generally aren't too big a problem for people living nearby.

One less noteworthy effect of a well explosion is that the CO2 generated from the combustion of the methane is carried high up into the atmosphere by the heat of combustion, where it is mixed by high-altitude winds (routinely 100 MPH).

One plan for CO2 sequestration from coal-fired powerplants is to inject the CO2 into old, empty gas wells. Like the methane, the CO2 is in a supercritical state in the well -- not so much a liquid as a very dense high pressure gas.

The difference between CO2 and CH4 comes when the well explodes. CO2 does not start a fire. Instead, it expands, and cools, and the cold CO2 will flow with the wind, against the ground, eventually dissipating.

A 1 GW (electrical) coal-fired powerplant will burn 2.2 GW (thermal) of coal (because it's about 45% efficient). That's about 7000 metric tons every day. It will produce 4.7 cubic kilometers of carbon dioxide per year, at standard temperature and pressure. That CO2 is fatal to mammals at concentrations greater than 4%.

So, if a sequestration field explodes after 10 years of sequestering the output from a 1 GW coal plant, it will create an invisible blob of CO2 that will be at least 7 km across before it dissipates to the point of being nonlethal.

Think about this thing for a bit. CO2 inhalation is fatal within a couple of minutes, and I suspect it is disabling well before that. Who is going to detect this blob of gas before being overcome? You cannot see it. You cannot run from it. You cannot stay indoors to escape. You cannot start your car to drive away from it. As the wind wafts it across the scenery, it kills every animal in its path. It could go for 50 kilometers or more before wind shear mixes it with enough air to become safe.

Not in my back yard, if you please.

Monday, June 09, 2008

Anya's Gift

For Anya's 6th birthday, we had a huge party. Over 50 people came. It was a blast.

We've been trying to reduce the accumulation of toys in our house, and presents from that number of people was going to be a problem. So, we told people not to bring presents, or if they did, bring something suitable for the Ronald McDonald house, which is a temporary home for the families of kids undergoing serious treatments at Stanford Hospital.

If anything, the haul got better (oy! consumerism). Here is Anya delivering her presents to the charity.

Monday, June 02, 2008

Discovery Launch

I just got back from watching the Discovery launch. My boss, Ed Lu (former 3-time astronaut, second from left), hosted us, which really made the experience for me because he was able to introduce us to lots of folks. Every time we walked into a restaurant, and every 5 minutes while we were at Kennedy Space Center, someone would smile and come over to talk with Ed. NASA doesn't pay well and most folks don't get to try wacky things like we do at Google, but they seem to have great interpersonal relationships. It's heartwarming to see.

On launch day, we were 3 miles from the pad at the media site. This is as close as you can get. We had a lot of waiting around to do. Here is a cherry spitting contest.

I know there is a great deal of speculation out there about whether hacking on camera hardware at Google makes one a babe magnet. While such question are only academic for me personally, I can tell you that getting out in the midst of a bunch of media types with some very customized photographic hardware attracts all sorts of attention. I don't actually know who this person is but I think we can all agree she's gorgeous, and she was very interested in the camera hardware and what Google was doing with it.

From our vantage point 3 miles away, the shuttle stack was just a little bigger than the full moon, which meant that the flame coming out the back was about that size too. There have been some comparisons to the shuttle exhaust being as bright as day....

Let me put that myth to rest. After two years of designing outdoor cameras, I can tell you that just about nothing is as bright as the sun. From our vantage point it had more angular size than the sun -- maybe 400 feet long by 100 feet wide, viewed from 3 miles, is 1.5 by 0.5 degrees.  The sun is 0.5 degrees across.  But the Shuttle plume is not as hot as the sun -- 2500 K at most, compared to 6000 K for the sun.  Brightness increases as the 4th power of the temperature, so the Sun's delivered power per square meter is something like 11x larger.  Furthermore, most of the light coming from the Shuttle is in the deep infrared where you can't see it, compared to the Sun's peak right at yellow.  So my guess is that the shuttle was lighting us up to 9,000 lux illumination.  That's twice as bright as an operating room, and way brighter than standard office bright (400 lux).  But it's just nothing like the 100,000 lux that you get outside in bright sunlight.  Nobody's going to get a suntan exposing themselves to the shuttle.  (Yes, the shuttle flame reflects off the exhaust plume, but the sun reflects off clouds, which are much bigger, so there is no relative gain there.)

Anyway, back to the people we got to meet. Here we are at lunch in the KSC cafeteria, the day before the launch. That guy two to my right is... named at the bottom of the blog. Have a guess. He had a really neat retro electronic watch and talked about how much he likes his Segway. Picture was shot by Jim Dutton, one of the F-22 test pilots who is now an unflown astronaut.

Here's a terrible picture of Scott Horowitz (former #2 at NASA, the guy who set the direction for the Ares rockets and Orion capsule) talking with Ed. The two were talking about their airplanes, a subject that gets both of them fairly animated ("I love my airplane. It's trying to kill me.")  Sadly, Ed's plane was subsequently destroyed by Hurricane Gustav (while in a supposedly hurricane-proof hanger) later this year.

Sorry about the quality, it was incredibly crowded and Ed and Scott weren't posing. This was on the day of the launch. Scott came out and looked at our Street View vehicle, then narrated the launch for us. Scott is a former 4-time astronaut and has a great deadpan delivery ("okay we just burned off a million pounds of propellant"); he's probably done it a hundred times.

Here's Mike Foale, who Ed has closed the hatch on twice (that means Mike was in the crew after Ed at the ISS twice).

I enjoyed meeting the people and looking at the hardware quite a bit more than the spectacle of the actual launch itself. Basically, the Shuttle makes a big white cloud, climbs out, loud noises ensue, and within two minutes you can just make out the SRB seperation with your unaided eyes, and it's gone. The Indy 500, for instance, is louder, and more interesting because there are always going to be crashes and various anomalies, which are not usually injurious and therefore lots of fun for the crowd. After meeting all those competent people who are working so hard to thread this finicky beast through a loophole in Murphy's law, I was just praying the thing wouldn't break on the way up.

P.S. That's Steve Wozniak, cofounder of Apple Computer.