Movement

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Engineers usually spend their time designing and building things — bridges, machines, electronic devices. Some do other things — strange things. We’ll look at one of them, today on Engineering Works!

A lot of the things engineers know about move — cars, airplanes, the electrons in a computer chip. If you think about it, everything moves. You do. So do we. So do cats and dogs, fish and birds. All of them different, right? But guess what. You can explain how and why all these things move – cat, fish or you – with a single unified theory.

Mechanical engineers working with experimental biologists have figured out that the way animals – including humans – move, is basically flow. Engineers know a lot about flow. Flow works in space and time to make the movement of material efficient. When you apply flow to animals, it means that they move to travel the greatest distance while using the least energy. In fact, they found that the same principles will explain movement as different as the buzzing flight of a house fly and a jet-powered airliner.

The engineers figured out that you can use simple physics – gravity, density and mass – to explain a lot of what happens when animals fly, swim or run. They call it constructal law and they say it explains why animals evolved over time the way they and we have.

Our time has flowed on past us and it’s time for us to move on out of here. See you next time.

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Tiny

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If you’re an engineer, a hole can be just as important as the stuff it’s drilled into. We’ll take a peek into some really tiny holes. Today. On Engineering Works!

Holes didn’t used to be much of a problem. Find the right drill and you’ve got holes. Then things started to get small and so did the holes. And making them got trickier. Now, we need really small holes — tiny ones like the holes in the chips and transistors that make your new iPod work. Drill bits like the ones you have for your handy electric drill won’t do it.

Engineers in Great Britain have figured out how to use something called electro-discharge machining, or EDM, to make the smallest holes yet ones so small you can’t see them without help from a microscope.

To get an idea of how small these holes are, let’s take a look at one of your hairs. Go ahead, pop one out. See how thin it is? You have to look pretty hard just to see the end of it. Depending on exactly how big your hair is, these guys could drill three or four holes into the end of it.

EDM uses carefully controlled sparks that eat their way into materials that conduct electricity. The size and shape of the electrode the sparks come from determine how big the hole is and its shape.

Our radio hole is just about filled for this week. We’ll see you next time.

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Clean manure

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When people talk about air quality, they usually don’t use the word – manure – in the same sentence. Maybe they should. We’ll see why. Today. On Engineering Works!

The generating plants that produce the electricity we use for almost everything also produce a lot of air pollution. They’re one of the Environmental Protection Agency’s big targets in its efforts to clean up the air we breathe.

One of the most important things the E-P-A wants to get out of the air is a gas called – nitrogen oxide. Or Nox. Power plants that burn coal puff out a lot of Nox. Nox is bad stuff. It’s one of the main ingredients that leads to ground level ozone. It’s also involved in acid rain and helps make greenhouse gases.

Engineers at Texas A&M University have found that if you add cattle manure to the coal that power plants burn, the amount of NOX that comes out of the smokestack goes down. What seems to happen is that compounds in the manure combine with the nitrogen that would otherwise go into Nox.

The E-P-A has tested the idea at a couple of its laboratories, and it really does work. Burning the manure also could get rid of the smelly stuff from areas where there’s a lot of cattle. That reduces air pollution of another sort. Keeps runoff from getting into the water supply, too.

We’re going to go do somehing about the air quality around here. See you next time.

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