A case study in the New England Journal of Medicine details the tragic story of an electrician who received a shock of 14,000V and was blinded as part of his injuries. Accompanying the article is this striking photo of the scars on his eyes, which resemble the plasma ball effects, the sort of thing you'd expect from a science fiction movie. Read the rest
On the East Coast of the US, electric demand is so high that utility companies can't take major transmission lines out of commission for maintenance and repair. Instead, workers fly up to the affected cable in a helicopter and work on the line while it's live — coursing with electricity. The helicopter hovers next to the line and the lineman leans out of a little bucket on the side and does his or her job, protected from electrocution by the same loophole that allows birds to safely land on those lines. As long as the entire contraption — lineman and helicopter — don't create a pathway from an area of high energy (the powerline) to an area of lower energy (the ground, for instance, or another power line that operates at a lower voltage) they're good to go. In order to do that, they have to energize the helicopter to the same voltage as the line.
Also check out this longer video with GoPro-style footage of helicopter-assisted transmission line repair and a British documentary following some of the men who do this job. Around six minutes in, the documentary has a nice explanation of how the workers energize the helicopter without killing themselves. Also, according to one of the linemen, "chicks dig it". Read the rest
If you enjoy the irony in the fact that the great East Coast blackout of 2003 was largely caused by a few untrimmed trees, then you're going to love Jon Mooallem's account of how America's squirrels are wreaking havoc on America's electricity system.
Using a Google news alert, he's cataloged 50 squirrel-caused power outages in 24 states — and that's just since Memorial Day. These aren't small outages either. Several of them have cut power to thousands of people at a time. Back in 1994, a squirrel took out the Nasdaq. These are kamikaze raids and they've led to an interesting phenomenon — technology developed specifically to protect our infrastructure from furry, tree-hopping rodents.Read the rest
"A concert on the engineering quad, University of Illinois," explains Tau Zero. "The arcs reproduced the fundamental tones of music played back through a PA system. Part of the Engineering Open House." Read the rest
The Joule Thief is a way of producing enough electricity to run small, but useful, electric lights using cast-off trash like pop-can tabs and "dead" batteries. It's especially handy in the Himalayas, writes inventor and Google Science Fair judge T.H. Culhane. There, electricity is a precious resource. But the components needed to build a Joule Thief are abundant, thanks to climbers and tourists who leave behind all sorts of surprisingly useful litter.
Last week, Culhane joined a G+ hangout sponsored by National Geographic and Girlstart to talk about the value in things we throw away and walk viewers through the construction of their very own Joule Thief. You can watched the video of the event, or read the instructions for building a Joule Thief at Culhane's blog.
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The fact that the Joule thief allows one to run a 3V LED from a 1.5 or 1.2 Volt battery would itself be astounding, because it means you only need half the number of batteries to get the same light.
Some of you are thinking "wait, maybe it enables you to use a single 1.5 volt battery to light a 3V LED instead of the usual two, but doesn't it just make that battery last half as long? Great question, but the answer is that the Joule Thief, which works by building up and collapsing a magnetic field around the torus (which acts as an electromagnetic inductor) actually is more efficient than using a battery directly because it PULSES the energy to the LED.
Salt water is still winning. Unfortunately.
Remember back during the Fukushima crisis, when you heard a lot of talk about why the people trying to save the plant didn't want to use sea water to cool the reactors? There were a number of reasons for that (check out this interview Scientific American's Larry Greeenemeier did with a nuclear engineer), but one factor was the fact that salt water corrodes the heck out of metal. Pump it into a metal reactor unit and that unit won't be usable again.
Now, the corrosive power of salt water is in the news again — and this time it's ripping through New York City's underground network of subways and utility infrastructure. I like the short piece that Gizmodo's Patrick DiJusto put together, explaining why salt water in your subway is even worse than plain, old regular water:
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When two different types of metal (or metal with two different components) are placed in water, they become a battery: the metal that is more reactive corrodes first, losing electrons and forming positive ions, which then go into water, while the less reactive metal becomes a cathode, absorbing those ions. This process happens much more vigorously when the water is electrically conductive, and salt water contains enough sodium and chloride ions to be 40 times more conductive than fresh water. (The chloride ion also easily penetrates the surface films of most metals, speeding corrosion even further.) Other dissolved metals in sea water, like magnesium or potassium, can cause spots of concentrated local corrosion.
Sixty milliseconds is fast. But sometimes, it's not fast enough. That's the gist of a great explainer by Cassie Rodenberg at Popular Mechanics, which answers the question, "Why do transformers explode?"
Before I link you over there, I want to add a quick reminder of what transformers actually are.
Although giant robots that turn into trucks do also explode from time to time, in this case we are talking about those cylindrical boxes that you see attached to electric poles. (Pesco posted a video of one exploding last night.) To understand what they do, you have to know the basics of the electric grid.
I find that it's easiest to picture the grid like a lazy river at a water park. That's because we aren't just talking about a bunch of wires, here. The grid is a circuit, just like the lazy river. Electricity has to flow along it from the power plant, to the customers, and back around to the power plant again. And, like a lazy river, the grid has to operate within certain limits. The electricity has to move at a constant speed (analogous to what engineers call frequency) and at a constant depth (analogous to voltage). This is where transformers come in. Read the rest
Barring a seriously crazy shift that plunges us quickly into an especially cold winter, 2012 will likely go down as the hottest year on record in the United States. More importantly, this broken record is part of a larger pattern that affects the whole world—record-breaking high temperatures are becoming, themselves, a bit of a broken record. On a global scale, counting average land and water temperatures, 2012 is (so far) the 11th warmest year on record—almost a full degree hotter than the 20th century average. Of the 12 warmest years on record, all of them have happened since 1998 (and the top 20 is made up of years since 1987).
Over time, that kind of long-term trend takes a toll. But for those of us who are lucky enough to live with relatively high levels of wealth, air conditioning, supermarkets, and all the luxuries of modern life, that toll is not always obvious. Sometimes, you have to look a little deeper to see how climate change is already affecting the American way of life.
So, what's climate change ruining today? How about electricity generation? Juliet Eilperin at The Washington Post has a story about how a consistent trend of high temperatures and drought has affected water reserves, and how those diminished reserves affect our ability to produce electricity.
Exit signs are so ubiquitous that they're almost invisible. Every public building has them. In fact, they are so common that, taken together, these little signs consume a surprisingly large amount of energy.
Each one uses relatively little electricity, but they are on all the time. And we have a lot of them in our schools, factories, and office buildings. The U.S. Environmental Protection Agency estimates that there are more than 100 million exit signs in use today in the U.S., consuming 30–35 billion kilowatt-hours (kWh) of electricity annually.
That’s the output of five or six 1,000 MW power plants, and it costs us $2-3 billion per year. Individual buildings may have thousands of exit signs in operation.
To put this into a bigger context: This is just one small part of what makes buildings, in general, incredibly energy intense. In the United States, we use more energy powering our buildings—from the lights, to the heating, to the stuff we plug into the walls—than we use to do anything else. Because of that (and because of the fact that electricity is mostly made by burning coal or natural gas) buildings produce more greenhouse gas emissions than cars.
Read more about the energy consumption of exit signs and how we can use less energy, while still getting the same services, at Green Building Advisor
Take a look at some stats on energy use in buildings at the Architecture 2030 website
Via Jess McCabeRead the rest