John Tierney writes a nice piece in the NY Times about a group of 100 scientists who express their opposition to the idea that is being promoted at the Global Warming conference in Bali.

The scientists say: "don't fight, adapt".

Both pieces are worth reading.

Don't miss the over one hundred comments at the end of Tierney's article. They cover the issue really nice. The encouraging thing is that even at the NY Times, more than 2/3 of the commenters express skepticism about AGW.

## Thursday, December 27, 2007

## Wednesday, December 26, 2007

### Auto X Prize definition

The Wired site writes about the auto X prize competition to be defined and started in 2008. basically it's about a car that gets a 100 MPG (miles per gallon) "efficiency".

That's a strange definition of "efficiency". Seems it's the standard definition in the press. This "Efficiency" is just about "how many mpg", for example: a 100 mpg car would be considered more efficient than a 80 mpg car.

That's not how an engineer would define "efficiency". An engineering (and logical, and correct) definition is: how much resources you use to do a given amount of work. In our example that means: how many mpg for a given car weight. It goes without saying that a 1000 kg. car will do more mpg that a 2000 kg. car. A 2000 kg car that makes 80 mpg is probably more efficient than a 1000kg car that makes 100 mpg. You have to state the weight of the car together with the mpg rating to get an efficiency rating.

So, the Auto X Prize people need to specify the minimum weight for the car, to qualify for the competition.

That's a strange definition of "efficiency". Seems it's the standard definition in the press. This "Efficiency" is just about "how many mpg", for example: a 100 mpg car would be considered more efficient than a 80 mpg car.

That's not how an engineer would define "efficiency". An engineering (and logical, and correct) definition is: how much resources you use to do a given amount of work. In our example that means: how many mpg for a given car weight. It goes without saying that a 1000 kg. car will do more mpg that a 2000 kg. car. A 2000 kg car that makes 80 mpg is probably more efficient than a 1000kg car that makes 100 mpg. You have to state the weight of the car together with the mpg rating to get an efficiency rating.

So, the Auto X Prize people need to specify the minimum weight for the car, to qualify for the competition.

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