Archive for the ‘Chemistry’ Category
Mercury, the innermost planet of our humble little solar system, is getting itself an orbital friend. The MESSENGER space probe (known as MErcury Surface, Space ENvironment, GEochemistry and Ranging to his nearest and dearest) is concluding a six-year sojourn through the dark void of space with an elliptical orbit around the tiny and otherwise inhospitable planet. Systems are about to get turned on and fully checked next week, before the data-gathering phase kicks off in earnest on April 4th. Science, isn’t it beautiful?
Like making circuit boards, but don’t like all of the toxic chemicals that you have to use to do it? You might want to take a look at Stephen Hobley’s directions, then. He’s claiming to be able to etch boards using only diluted hydrogen peroxide, vinegar, and a bit of table salt.
He’s got an analysis of the chemical reaction on his site, and mentions that the byproduct is probably toxic, so you should probably be careful about handling and disposing of the stuff.
- Make: Online » Circuit Skills: Circuit Board Etching, sponsored by Jameco
- Make: Online » Salt and vinegar circuit etching
- Make: Online » Laser cutting circuit boards
- Make: Online » Printing circuit boards lecture @ 27C3
- Make: Online » Etching a portrait into a PCB
- Make: Online » The 5-minute circuit board agitator, or, making temporary tools
Most of our readers will know that one of the most common types of residential smoke detectors actually contains radioactive material—specifically, an isotope of americium—which is used to ionize air molecules in the detector itself. In this video, the always-engaging Bill Hammack, aka Engineer Guy, explains both the ionizing detector and the circuit that contains it, with particular focus on the MOSFET device which is the other critical component in that circuit (and is, incidentally, the namesake of Phil Torrone’s cat). Characteristic Bill quote: “To me, this is engineering at its best: Simple, reliable, and inexpensive. And saving countless lives.” Thanks, Bill, as always!
Interesting article from IEEE Spectrum about the potential benefits of developing a usefully rechargeable lithium-oxygen cell (for use, most importantly, in electric cars) and the challenges that remain for that research. So-called “air batteries,” in which one of the reacting chemical species is atmospheric oxygen, are already widely employed, for instance, in hearing-aid batteries, which are commonly zinc-air cells with a piece of adhesive film that must be removed before use to allow atmospheric oxygen onto the cathode. The know-how to make lithium-air cells is available right now; the hard part is making the reverse process practical over many recharging cycles. [Thanks, Glen!]