Linkdump: August 2015

Updated 9/2 to add language warning.

Evil Mad Engineers

Every month or two since 2009, someone has sent me a copy of a particular comic from the webcomic Cowbirds in Love.  Here is today’s example, from @benk_at_work on twitter:

@benk_at_work tweets...

evil mad engineers @ cowbirds in love

 

Sigh.

There is, of course, only one appropriate way to respond in a situation like this: with another comic.

Back in 2011, I wrote an era-appropriate semi-autobiographical rage comic, that I could use as a standard response when people sent me that comic.

f7u12

Joking aside, we really do spend a lot of our time engineering— and many of our friends and colleagues are bona fide engineers. On the other hand, I love to cook, but that doesn’t make me a chef either.

Geek Tourism: Biosphere 2

Biosphere2-1

Biosphere 2 is an enormous earth science laboratory, originally built as an attempt to create a closed ecosystem. The goals were to study long term viability of an isolated human habitat, such as might be needed for long term space travel or colonization.

Biosphere2-17

The results of the initial experiments were a (fascinating) mixed bag. The goal of a strictly closed ecosystem was not met for a variety of reasons. However, some of the results have improved our understanding of the effects of climate change, such as how increased CO2 levels lead to acidification of the ocean habitat and coral bleaching.

Biosphere2-3

The facility is now being used both for education and for research. The enormous agricultural greenhouses have been transformed by the University of Arizona into the Landscape Evolutionary Observatory, a large-scale carefully-controlled long-term study of soil processes. It serves as an experimental bridge between computer models, small-scale laboratory experiments, and the real world.

Biosphere2-13

Some of the original biomes are relatively unchanged and have been growing since the project started in 1991. It is striking to have all hint of surrounding desert obscured by the vines of the rainforest.

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One of the most fascinating engineering aspects of the facility are the “lungs,” which are accessed through long narrow tunnels branching off of the main facility.

Biosphere2-22

The lungs were used to compensate for the changes in pressure and temperature. The two domed buildings have flexible inner liners that can expand and contract. A weight attached to the center of the liner makes them look toroidal inside of the dome.

Biosphere 2

The facility was built outside of Tucson, and is strikingly beautiful, surrounded by wildlife including lizards, snakes, tarantulas, jack rabbits, coyotes, gila monsters, and an incredible variety of birds and insects. We’ve put a few more pictures from our visit in albums on flickr here and here. Tours are available to the public daily, and it’s worth the drive and ticket price if you’re nearby.

Linkdump: July 2015

XL741: Principles of Operation

XL741

Our two “dis-integrated circuit” kits are the Three Fives Discrete 555 Timer, and the XL741 Discrete Op-Amp. These two kits are functional, transistor-level replicas of the original NE555 and μA741 (respectively), which are two of the most popular integrated circuits of all time.

Last year, we wrote up a detailed educational supplement for the Three Fives kit, that works through its circuit diagram and discusses its principles of operation down to the transistor level. Today, we are doing the same for the XL741 kit, and releasing an educational supplement that explains how a ‘741 op-amp IC works internally, down to its bare transistors and resistors:

XL741 Documentation (PDF)

This ability to peek inside the circuit makes the XL741 a unique educational tool. In what follows, we’ll work through the circuit diagram, discuss the theory of operation of the ‘741 op-amp, and present some opportunities for experiments and further exploration.

You can download the supplement here: XL741 Principles of Operation (1.1 MB PDF)

Additional Resources: