Archive for November, 2006

Saving Venice

November 30th, 2006 by Gene
Venice
 

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Venice has a problem. We’ll look into what engineers are doing to help. Today, on Engineering Works!

The beautiful piazzas and famous canals of Venice are in trouble — they’ve got more water than they know what to do with. The thousand-year-old city is sinking into its famous lagoon, a few inches at a time. The water level is nine inches higher than it was a hundred years ago, 40 inches higher than 250 years ago.

The high water damages brick walls never intended to be in the water. There’s a lot of salt from the Adriatic Sea, too. Between the water and the salt, a lot of the city’s beautiful historic buildings are rotting.

A team of Italian engineers is working on a gigantic government-funded construction project they say will save Venice from the rising water. At its heart is a high-tech system of 300-ton concrete barriers that will be raised and lowered to protect the city from damaging tidal surges. Plus thousands of steel poles and other barriers on the floor of the lagoon to slow down the water.

They also plan to re-establish vanished wetlands and reinforce damaged foundations in the city itself. Altogether, the project will cost more than $4 billion and take seven years to complete.

Not everyone thinks it’s a good idea — or that it will help. But the engineers think it will. And it’s better than letting the city sink, they say.

We say, that’s it for this time. See you next week.

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Explosives

November 21st, 2006 by dstmartin
explosion
 

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Explosions all go bang, but they’re not all the same. We’ll check into how and why. Today, on Engineering Works!

We’ve had explosives a long time — gunpowder, dynamite and TNT. Plastic explosives. They cause death and destruction in the wrong hands. But engineers do good things with explosives, too — move the landscape around for highways, bridges and big buildings; demolish old buildings cheaper than tearing them down by hand.

Most explosives get their power from burning. That’s all an explosion is – gas produced by burning, really fast burning. And you get a lot of gas, very quickly. It’s the pressure from that gas that blows things apart. How much gas is produced how fast determines how powerful an explosive is. Plastic explosive is more powerful than gunpowder because it burns – and produces its gas – a lot faster.

Instead of burning, some explosives produce gas by breaking down complex molecules into simpler molecules that just happen to be gases. They produce only enough heat to continue chemical reactions that produce gas like ordinary explosions.

One explosive – triacetone triperoxide – breaks down into oxygen and ozone instead of burning. It’s very destructive because this breakdown produces a lot of these gases in the blink of an eye.

Engineers use explosives like these to save lives, too. They use one called azide to produce the gas that inflates the airbag in your car when you hit something hard.
It’s time for us to explode on out of here. See you later.

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Ballistic Transistor

November 15th, 2006 by Gene
Transistor
 

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When the transistor was new, it was pretty revolutionary. Now, engineers are revolutionizing the transistor. We’ll watch, today on Engineering Works!

Transistors have been around since 1949, and they’ve changed the way we do electronics. There used to be bulky vacuum tubes. Now we have transistors and computer chips. Transistors are tiny solid-state switches that turn electricity off or on, or change it in some way. Every chip in your computer has millions of them.

Transistors work by allowing electricity to flow through them, or blocking that flow. In computer chips, you get a digital one when the electricity is flowing. When it’s stopped, you get a zero.

Transistors have worked pretty well for almost 60 years. But whenever you shut off the flow of electricity through a transistor it takes time – less than a moment, but still time – to get to full speed again. This limits how fast transistors can switch on and off – and how fast computer chips process information. But not to worry. Engineers have come up with a new faster transistor that promises to put the speed back into transistors and computer chips. It works like this.

Instead of turning the stream of electricity off or on, the new transistor bounces it around corners. When the electricity bounces one way, it’s on. When it bounces the other way, it’s off.

Our electricity is turning off, so we’ll bounce on out of here. See you next time.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU FM in College Station. We’re on the World Wide Web, too. Visit us at engineeringworks.tamu.edu.

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Oil Water

November 2nd, 2006 by Gene
Oil and Water
 

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They say oil and water don’t mix, and it’s true — usually. Some chemical engineers are turning this old saying on its head. We’ll take a look at how they did it, and why. Today, on Engineering Works!

Oil and water – and other some other chemicals – don’t like each other. Think of ping pong balls and golf balls. If you pour a bucket of each into a bigger bucket, they’ll be all mixed together — for a while. Eventually, though, the ping pong balls will end up on top and the golf balls on the bottom. That’s what happens with oil and water.

Sometimes you want oil and water to mix together, like when you’re cleaning up an oil spill. The water needs to carry the oil away from wherever it’s spilled. This isn’t hard. Adding chemicals called surfactants allow oil and water to mix together in what chemists call an emulsion. That’s good. Until you want to separate the oil and water again. That doesn’t work so well.

This is where chemical engineers come in. They’ve come up with a new surfactant that they can turn on and off. All it takes is carbon dioxide or nitrogen. Use one and the surfactant turns on. Use the other and it turns off.

After you’ve cleaned up your oil spill, you can separate the water from the oil for recycling or more cleanup.

Our oil and water are separating fast. We’ll see you later.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU FM in College Station. We’re on the World Wide Web, too. Visit us at engineeringworks.tamu.edu.

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