Unless you drive a hybrid with regenerative braking, almost all the kinetic energy that comes from burning gasoline is dissipated as heat when you apply the brakes to stop your car. It would be interesting to measure just how much heat is added to our atmosphere on a daily basis just from people stopping their cars.

I could come up with back-of-the-envelope number if I knew how many brake pads and shoes are sold worldwide each day, and on average how much braking energy each pad or shoe contained. Anybody have a ballpark number on either of those?

Update (2006-04-18): It occurred to me after I made this post that most of the energy that comes from burning gas to move a car eventually is dissipated as heat: through the engine block; through the exhaust; from the breakpads; from the stereo; etc. Focusing on just the braking part of it is rather pointless, so forget it.

I meant to make some posts yesterday; that is, before I became totally engrossed in
flOw.

Simply addictive.

I stopped at the gas station on the way home from work today. With gas prices at $1.034/L, the $40 worth that I purchased barely filled 3/4 of my tank. Being the cheap bastard that I am, I was immediately reminded of an article I recently came across on Treehugger that recommends conserving gas by driving the speed limit. It's good advice but, as an engineer, I found their expanation somewhat lacking. So here is my best attempt at explaining, in the language of high-school physics, why driving slower uses less gas.

There are two parts of driving that are worth considering. First, how much energy is spent getting a vehicle up to speed, and second, how much is used to sustain that speed.

Let's consider the first: accelerating to full speed. If you remember from your high school physics classes, the kinetic energy of a moving object is proportional to the square of its velocity, or e=mv²/2. What this means is that to go twice as fast requires four times as much energy. For example, to accelerate from 0-100km/h requires in your car requires four times as much energy, and therefore four times as much gasoline, as accelerating from 0-50km/h.

And that's just the energy to get up to speed. In a frictionless and air-resistanceless world, you wouldn't need any more energy, the car would just coast forever. But we don't live in such a world, which brings us to the second point, sustaining the velocity.

Air resistance and internal friction increase propotionally with the speed that you drive. If you drive twice as fast, the air pushes twice as hard against you. This shouldn't come as a shock to anybody who has held their hand out the window of a moving vehicle. So how does that translate into fuel consumption?

If you followed the link to the Treehugger article, you'd already know that fuel consumption is proportional to the speed you drive. But how? Think back again to your high school physics class: work is equal to force times distance, or w=fd. You'll also remember that work and energy are the same thing. So if you drive faster, you'll have to apply a force against a higher air resistance. Over the same distance, driving faster will require more work, which is energy, which is gasoline, which is dollars at the gas station. Driving twice as fast requires twice as much gasoline over the same distance.

So there you have the basic physics of how it's cheaper to drive the speed limit (or less) from a cheap bastard of an engineer.

Ars Technica is reporting on a new technique that researchers at Epson have developed to manufacture semiconductors. They liken it to spray painting chips:

Their approach is to use either a "spray painting" technique or ink jet deposition to grow features. They have designed an organo-silicon molecule, which readily dissolves in common solvents. This molecule is then deposited by either a spraying or ink jet technique on a silicon substrate to form the semiconductor features. The whole wafer is then heated causing the organic molecules to decompose and form amorphous silicon. The amorphous silicon can then be converted to crystalline silicon by irradiation with standard UV lasers. So far, researchers have managed to demonstrate a proof-of-concept by growing thin film transistors used for controlling the pixels on LCD displays.

They are currently able to produce chips at feature size of 250nm. Not bad for a first shot. And that number is bound to come down with more research. It'll be interesting to see if anything comes of it.

On Friday night, Mandy's office held a small poker tournament. Considering what life lessons Steve Pavlina learned from playing poker and blackjack, I figured I'd give it a try.

I didn't expect to do very well, despite skipping my Friday workout to practice at home on our PS2 with World Championship Poker, but I was shocked a just how hard I sucked at it. I finished 20th or 21st out of 24.

So being the kind of person who just can't stand to suck at something that rests so firmly on one's mathematical and analytical abilities, and knowing that assessing risks and capitalizing on opportunities is something that I'll need to learn if I'm ever going to start a company, I've downloaded the PokerStars.net client to get some more practice.

We'll see if it helps any at the next tournament.

Aside: Something tells me that gambling is one of the two things Dave Pollard chose to leave off his list things to do when you're blue.