Archive for September, 2005


September 28th, 2005 by dstmartin

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Life is a gamble, they say. Well, we’re going to roll the dice and take a look at risk. Today, on Engineering Works!

Some things are just risky. Everybody knows that — bungee jumping, skydiving. How about driving to work every morning or living across town from a nuclear reactor?

Engineers think about risk all the time. It’s a lot of what they do. To engineers, risk is something they can calculate. How long until that transistor burns out. What happens then, and what can we do about it? Will the airplane crash? Or will your TV just go black. Same transistor; different risk.

Most of us think about risks with our guts instead of our heads. We all know people who refuse to fly because it’s risky. Those same people drive to work on crowded highways and think nothing of it. If you look it up, traffic accidents injure and kill many more people than airplane crashes.

We all have little quirks like this. Usually it has to do with the way we think about what we do. If it’s something we think we control, it must not be very risky. If someone else controls it, it feels riskier.

Engineers help us reduce many of life’s risks. Others we can’t avoid. The most useful thing is to try to understand the risks around us and make intelligent choices.

And maybe take a pass on the sky-surfing lessons.


Space Junk

September 21st, 2005 by dstmartin

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We’re going to talk trash like you’ve never seen — space junk. Today, on Engineering Works!

The next time you go outdoors, stop a minute and look straight up in the air. You can’t see it from here, but there’s a whole junkyard floating up above your head. It’s the stuff we’ve left behind from almost 50 years of space exploration.

Think about it. There’s so much junk in orbit up there that nobody knows for sure how much there really is. At least 100,000 pieces of stuff, maybe millions. More than 7,000 of them the size of a baseball or bigger. Some as small as chips of paint. In fact, a lot of it is chips of paint, from rockets and satellites. A few – broken down or worn-out satellites – are as big as washing machines.

Don’t snicker at those orbiting paint chips, either. They don’t sound like much, but they’re moving at more than 17,000 miles an hour. Anything moving that fast can do real damage if it hits something. One chip hit a window on the space shuttle. It gouged a crater as big as your thumbnail. Imagine what one of those dead satellites could do.

Engineers are designing shields to protect against collisions with orbiting junk. It’s a tough assignment – shields have to be strong enough to stop the junk before it hits anything important and light enough to lift into orbit.

Time to take out our trash. See you later.

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Speed Spies

September 14th, 2005 by dstmartin

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If your foot gets heavy on the gas pedal sometimes, this one may be for you. No more speeding tickets. Today – on Engineering Works!

Engineers in Great Britain have come up with an almost foolproof way for drivers with heavy feet to avoid speeding tickets – even better than the highway patrol.

It’s called the speed spy system. It uses the satellite-based global positioning system – GPS – and a digital map of the area you’re driving in, to keep you under the speed limit.

The speed spy works like this. A GPS receiver in your car keeps in touch with the GPS system’s satellites, so it knows where your car is, all the time. The system measures how long it takes you to get from one spot to the next and calculates how fast you’re going. If it’s faster than the speed limit posted as part of the digital map, it eases off on the gas pedal, or puts a digital foot on the brake. Even if you think your speed is fine.

You can override the system in emergencies – if you need to get out of the way of a reckless driver, for instance. If you’re late for work, you’re just out of luck.

The researchers who tested speed spy say it could save a thousand lives a year if everyone in Britain used it.

We’re not sure if we like this idea or not. But we’re still on our way out of here. See you next time.


DNA Factory

September 7th, 2005 by dstmartin

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One of the things engineers do is design things. Then they redesign them. Some engineers are redesigning bacteria. We’ll see why, today on Engineering Works!

You don’t usually hear engineer and bacteria in the same sentence. But special bacteria are the target of some chemical engineers’ design skills. If you’ve been keeping track of the exploding field of bio-technology, it makes perfect sense. Here’s why.

Biotechnology changes the way organisms work by modifying their DNA. Bacteria with modified DNA can be turned into factories. They make all kinds of important stuff, from antibiotics to anti-cancer drugs. Pretty neat. But there’s a problem: many bacteria factories wear out pretty quickly. One bacterium produces the important antibiotic erythromycin. But it stops after one day. Another bacterium keeps turning out erythromycin for five days. Figuring out the difference is important.

Chemical engineers are using a nifty tool called a DNA microarray to figure it out. DNA microarrays are computer chips that track what each of the bacterium’s genes is doing. This is important. Even a bacterium has lots of genes, and sometimes a change in one or two can make a big difference. The microarray helps engineers see which gene is doing what. If they can see that, they can figure out what they need to change so the bacterium will do what they need it to. Like make more antibiotic.

Our genes are working fine, thank you. But we’re still out of time.