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Bbanerje // CC-BY-SA-3.0

# Watch: Why Are I-Beams Shaped Like the Letter I?

Bbanerje // CC-BY-SA-3.0

English speakers know it as an "I-beam" for its similarity to the capital letter "I" (with serifs). In many European languages it's a "double-T" beam. Or you may know it as an "H-beam." In any case, this beam is the support structure for tons of modern buildings. So why is it shaped that way?

Long story short, the combination of the "web" (the middle bit of the beam) and the "flange" (the top and bottom bits) offers resistance both to shear and bending forces. Watch this short video for the math behind the engineering you're probably sitting on right now:

Important note: In the video, there is a typo in the max deflection formula shown. The numerator shown should include L to the fourth power, not third. (On desktop browsers, an annotation fixes this, but on mobile it often doesn't show up!) If you're not into video explanations, Wikipedia's page on I-beams is pretty solid. For more videos like this, check out Real Engineering on YouTube.

(Photo courtesy of Bbanerje // CC-BY-SA-3.0.)

The North Face
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Design
The North Face's New Geodesic Dome Tent Will Protect You in 60 mph Wind
The North Face

You can find camping tents designed for easy set-up, large crowds, and sustainability, but when it comes to strength, there’s only so much abuse a foldable structure can take. Now, The North Face is pushing the limits of tent durability with a reimagined design. According to inhabitat, the Geodome 4 relies on its distinctive geodesic shape to survive wind gusts approaching hurricane strength.

Instead of the classic arching tent structure, the Geodome balloons outward like a globe. It owes its unique design to the five main poles and one equator pole that hold it in place. Packed up, the gear weighs just over 24 pounds, making it a practical option for car campers and four-season adventurers. When it’s erected, campers have floor space measuring roughly 7 feet by 7.5 feet, enough to sleep four people, and 6 feet and 9 inches of space from ground to ceiling if they want to stand. Hooks attached to the top create a system for gear storage.

While it works in mild conditions, the tent should really appeal to campers who like to trek through harsher weather. Geodesic domes are formed from interlocking triangles. A triangle’s fixed angles make it one of the strongest shapes in engineering, and when used in domes, triangles lend this strength to the overall structure. In the case of the tent, this means that the dome will maintain its form in winds reaching speeds of 60 mph. Meanwhile, the double-layered, water-resistant exterior keeps campers dry as they wait out the storm.

The Geodome 4 is set to sell for \$1635 when it goes on sale in Japan this March. In the meantime, outdoorsy types in the U.S. will just have to wait until the innovative product expands to international markets.

[h/t inhabitat]

Jonathan How, MIT
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technology
New MIT Technology to Help Drones Dodge Obstacles May Make Deliveries Easier
Jonathan How, MIT

New technology developed by MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) may help drones dodge collisions as they fly, making things like drone pizza delivery a whole lot more plausible on a large scale.

Whether you’re a human or a drone, moving through a city always involves a certain amount of uncertainty. Will that light turn green as you approach? Will a pedestrian bump into you? Will a pigeon fly in your face? Will there be a sudden road closure for a parade, or a newly installed crane at a construction site? And if there’s one thing that machines tend to be bad at, it’s dealing with uncertainty. For a fast-flying drone, navigating with a static map just won’t cut it in the real world.

So CSAIL researchers created NanoMap, a new system that can model uncertainty, taking into account that, as a drone flies, the conditions around it might change. The technology helps the drone plan for the fact that it probably doesn’t know precisely where it is in relation to everything else in the world. It spends less time calculating the perfect route around an obstacle, relying instead on a more general idea of where things are and how to avoid them, allowing it to process and avoid potential collisions more quickly.

It features depth sensors that constantly measure the distance between the drone and the objects around it, creating a kind of image for the machine of where it has been and where it is going. “It’s kind of like saving all of the images you’ve seen of the world as a big tape in your head,” MIT researcher Pete Florence explains in a press release. “For the drone to plan motions, it essentially goes back into time to think individually of all the different places that it was in.”

In testing, the NanoMap system allowed small drones to fly through forests and warehouses at 20 miles per hour while avoiding potential collisions with trees and other obstacles.

The project was funded in part by the Department of Defense’s DARPA, so it could be used as part of military missions, but it would also be helpful for any kind of drone-based delivery—whether it’s ferrying relief supplies to combat zones or your latest Amazon Prime package.

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