Five dangerous things you should let your kids do

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Posted Monday, January 07, 2008 by Dave Harms   

Okay, so Gever Tulley isn't a parent, and maybe his perspective would change if he had kids of his own. But he makes some good points. I certainly benefited as a child from a lot of freedom to explore, although my guardian angels probably put in a lot of overtime.

A DC power grid?

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Posted Tuesday, October 09, 2007 by Dave Harms   

Back in September green wombat reported on scientist David Mills' conclusion that a solar farm 92 miles on a side would provide enough energy to power the entire US. Oddly, the article also states that the power grid would have to be reworked for DC instead of AC to minimize transmission losses; presumably the author means conversion losses not transmission losses. In the late 1800s Thomas Edison pushed hard for acceptance of DC power (even electrocuting dogs and cats to demonstrate the dangers of AC), but one of the reasons DC eventually lost out to Nikola Tesla's AC system was that AC power could easily be stepped up (via transformers) to higher voltages for transmission over long distances, and then stepped back down for local use. If you don't have high voltage you need much larger wires to carry the current.

If a DC grid is needed, and becomes a reality, Edison will have the last laugh. And had his lifelong rival not been cremated the US could have generated all the energy it needs from Tesla spinning in his grave.

UPDATE: I had a chat with a friend of mine who's an engineer with the local power utility, and he enlightened me on DC power transmission. DC current flows through the entire cable; AC current tends to flow through the outer part of the cable due to something called skin effect, a result of the AC current's electromagnetic field. That means that for a given diameter of (solid) wire you can push a lot more power with DC. Solid state devices (great honking big ones) are used to transform DC voltages to/from the high values needed for long distance transmission.

And despite Tesla's victory, long distance AC transmission has higher losses than DC, and requires greater isolation/insulation. That means it costs less to build and operate a DC transmission line. Everything points to a DC grid somewhere down the line.

Given that everything in our homes runs on AC, I think it's safe to say that it will be a long time before we see DC power from the generating station (where it will likely originate as AC anyway) all the way to the plug.

Underground cities

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Posted Monday, August 20, 2007 by Dave Harms   

One of my favorite blogs is BLDGBLOG; Geoff Manaugh's take on architecture is highly readable, and his flights of fancy are a treat. Check out this post on the underground cities of Cappadocia, Turkey.

Claymation would've been cheaper, but dang, this is pretty good

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Posted Tuesday, May 22, 2007 by Dave Harms   

I came across this commercial about 45 minutes after FedEx dropped off a package. Lovely bit of animation, although I can't help but wonder how much of that international shipping fee I paid went into the ad fund. Oh well.

The mind of Walter Murch

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Posted Tuesday, April 10, 2007 by Dave Harms   

Here's another gem from Geoff Manaugh at BLDGBLOG. Film editor Walter Murch may seem like an odd interview choice for an architectural blog, but Murch's interests intersect the architectural plane at a number of points, including an unexpected connection between Copernicus and the Pantheon. I visited the Pantheon in 1997 and I remember being both disappointed to discover that this ancient building was not made of cut stone, and boggled at the thought of a 1900 year old concrete structure. But the Murch interview is about much more than the Pantheon and an ancient idea that the planets revolve around the sun; topics include sound recording and archicture, surveillance recording, and an inspired idea for a real-time high def video feed of the earth, from orbit.

Whatever floats your boat

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Posted Friday, February 16, 2007 by Dave Harms   

Tired of the same boring old canal locks? Want something that's a bit more like a slo-mo carnival ride? Take a turn on the Falkirk Wheel.

I have no idea how cost-effective it is to build a device like this is for lifting boats, as compared to a traditional lock, but it's cheap to operate. It takes about the same electrical energy to go through one half rotation as is needed to boil eight kettles of water.

And it's a stunning bit of engineering.

And for those of us with short attention spans, the time lapse version:

Look! Up in the sky! It's a bird! It's a plane! It's a...a...banana!

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Posted Wednesday, January 17, 2007 by Dave Harms   

Yessir, it's a banana. Not only that, it's a giant geostationary banana floating high over the state of Texas. Or at least that's the plan, with a launch date scheduled for 2008. The banana will be constructed with a bamboo and balsa wood frame, then covered with yellow nylon and filled with helium.

This banana idea is ripe, even if the team seems to have occasional trouble spelling "engineering".

It's nice to see the Canada Council for the Arts kicking in a few tax bux, but these folks are still well short of their million dollar budget, and they can use some technical and administrative help.

New line!

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Posted Tuesday, December 26, 2006 by Dave Harms   

The best four second video on the web (although you may have to be of a certain vintage to get the joke).

[HT: The man who went to dinner with Ursula Andress]

Queso Menonita

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Posted Tuesday, November 28, 2006 by Dave Harms   

My Cajun friend Andrew Guidroz II, political mover/shaker and preserver of farming tradition, pointed me to an NPR story about a famous Mennonite cheese which is about to lose its character, thanks to the Mexican government's upcoming pasteurization requirement.

Despite growing up Mennonite (and on a farm, no less) I have had little contact with the very traditional groups within the Mennonite culture. When I was at the University of Waterloo my roommates and I bought raw milk from one of the nearby Old Order farms. I did my first milk run on a dark winter evening, and pulling onto the farmyard I was struck by the complete absence of electric light. The only illumination was the yellow flame of a kerosene lamp glowing behind a barn window.

The farmer filled the jugs I'd brought with fresh milk poured from a can; I paid him and thanked him. And I drove back to my electric world.

How to deal with excesses

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Posted Monday, October 09, 2006 by Dave Harms   

Geoff Manaugh over at BldgBlog comments on this ring launcher for satellites and other payloads, as being studied by the US Air Force. The launcher would gradually accelerate the payload to Mach 23 before sending it up a 30° ramp. Geoff says:

Rather than satellites encased in sleds, however, how about sheds? Ice-fishing sheds. Or whole suburbs, thrown into space.

With the US housing market tanking and supply of McMansions growing I look for this idea to get some serious traction.

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