Big Chemistry: Catalysts

I was fascinated by the idea of jet packs when I was a kid. They were sci-fi magic, and the idea that you could strap into an oversized backpack wrapped in tinfoil and fly around was very enticing. Better still was when I learned that these things weren’t powered by complicated rockets but by plain hydrogen peroxide, which violently decomposes into water and oxygen when it comes in contact with a metal like silver or platinum. Of course I ran right to the medicine cabinet to fetch a bottle of peroxide to drip on a spoon from my mother’s good silverware set. Needless to say, I was sorely disappointed by the results.

My little impromptu experiment went wrong in many ways, not least because the old bottle of peroxide I used probably had little of the reactive compound left in it. Given enough time, the decomposition of peroxide will happen all by itself. To be useful in a jet pack, this reaction has to proceed much, much faster, which was what the silver was for. The silver (or rather, a coating of samarium nitrate on the silver) acted as a catalyst that vastly increased the rate of peroxide decomposition, enough to produce jets of steam and oxygen with enough thrust to propel the wearer into the air. Using 90% pure peroxide would have helped too.

As it is for jet packs, so it is with industrial chemistry. Bulk chemical processes can rarely be left to their own devices, as some reactions proceed so slowly that they’d be commercially infeasible. Catalysts are the key to the chemistry we need to keep the world running, and reactors full of them are a major feature of many of the processes of Big Chemistry.

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Contrails Are A Hot Topic, But What Is To Be Done?

Most of us first spot them as children—the white lines in the blue sky that are the telltale sign of a flight overhead. Contrails are an instant visual reminder of air travel, and a source of much controversy in recent decades. Put aside the overblown conspiracies, though, and there are some genuine scientific concerns to explore.

See, those white streaks planes leave in the sky aren’t just eye-catching. It seems they may also be having a notable impact on our climate. Recent research shows their warming effect is comparable to the impact of aviation’s CO2 emissions. The question is then simple—how do we stop these icy lines from heating our precious Earth?

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A design sketch of a partially disassembled candybar mobile phone. The enclosure is a clamshell of plastic that envelops the functional internals of the device and is illustrated to the right upper corner of the image, slightly overlapping the internals evoking the idea of the internals being inserted into the cover. The words "buttons part of the cover" are written toward the top with an arrow toward the numpad and "plastic shell with various design" is written toward the bottom with an arrow toward the translucent blue shell.

The Nokia Design Archive Is Open For Viewing

During the Cambrian Explosion of cellphone form factors at the turn of the millenium, Nokia reigned supreme. If you’d like to see what they were doing behind the scenes to design these wild phones, you’ll love the Nokia Design Archive from Aalto University.

Featuring images, presentations, videos and a number of other goodies (remember transparencies?), this collection gives us some in-depth insight into how consumer products were dreamed up, designed, and brought to market. Some projects require more reading between the lines than others as the Archive is somewhat fragmented, but we think it could still be an invaluable peek into product design, especially if you’re working on projects that you want to be usable outside of a hacker audience.

The Archive also includes approximately 2000 objects including many unreleased “unknown” models and prototypes of phones that actually did make it into the wild. While we’d love to get our hands on some of these devices IRL, having images with reference colors is probably the next best thing. Having replaced a number of smartphone screens, we hope more hackers take up the buttons and indestructible casing of these elegant devices for a more civilized age.

Thanks to [Michael Fitzmayer] for the tip! Be sure to checkout his work on Nokia N-Gage phones, including an SDK if you too love to taco talk.

Mining And Refining: The Halogens

I was looking at the periodic table of the elements the other day, as one does, when my eye fell upon the right-hand side of the chart. Right next to the noble gases at the extreme edge of the table is a column of elements with similar and interesting properties: the halogens. Almost all of these reactive elements are pretty familiar, especially chlorine, which most of us eat by the gram every day in the form of table salt. As the neighborhoods of the periodic table go, Group 17 is pretty familiar territory.

But for some reason, one member of this group caught my attention: iodine. I realized I had no idea where we get iodine, which led to the realization that apart from chlorine, I really didn’t know where any of the halogens came from. And as usual, that meant I needed to dig in and learn a little bit about the mining and refining of the halogens. At least most of them; as interesting as they may be, we’ll be skipping the naturally occurring but rare and highly radioactive halogen astatine, as well as the synthetic halogen tennessine, which lives just below it in the group.

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Time-of-Flight Sensors: How Do They Work?

With the right conditions, this tiny sensor can measure 12 meters

If you need to measure a distance, it is tempting to reach for the ubiquitous ultrasonic module like an HC-SR04. These work well, and they are reasonably easy to use. However, they aren’t without their problems. So maybe try an IR time of flight sensor. These also work well, are reasonably easy to use, and have a different set of problems. I recently had a project where I needed such a sensor, and I picked up a TF-MiniS, which is a popular IR distance sensor. They aren’t very expensive, and they work serial or I2C. So how did it do?

The unit itself is tiny and has good specifications. You can fit the 42 x 15 x 16 mm module anywhere. It only weighs about five grams — as the manufacturer points out, less than two ping-pong balls. It needs 5 V but communicates using 3.3 V, so integration isn’t much of a problem.

At first glance, the range is impressive. You can read things as close as 10 cm and as far away as 12 m. I found this was a bit optimistic, though. Although the product sometimes gets the name of LiDAR, it doesn’t use a laser. It just uses an IR LED and some fancy optics.

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Forgotten Internet: UUCP

What’s Forgotten Internet? It is the story of parts of the Internet — or Internet precursors — that you might have forgotten about or maybe you missed out on them. This time, we’re looking at Unix-to-Unix Copy, more commonly called UUCP. Developed in the late 1970s, UUCP was a solution for sending messages between systems that were not always connected together. It could also allow remote users to execute commands. By 1979, it was part of the 7th Edition of Unix.

Ken Thompson and Dennis Ritchie may have used UUCP on a PDP-11 like this one. (Photo via Computer History Museum/Gwen Bell)

Operation was simple. Each computer in a UUCP network had a list of neighbor systems. Don’t forget, they weren’t connected, so instead of an IP address, each system had the other’s phone number to connect to a dial up modem. You also needed a login name and password. Almost certainly, by the way, those modems operated at 300 baud or less.

If a computer could dial out, when someone wanted to send something or do a remote execution, the UUCP system would call a neighboring computer. However, some systems couldn’t dial out, so it was also possible for a neighbor to call in and poll to see if there was anything you needed to do. Files would go from one system to another using a variety of protocols.

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No Ham License? Listen Anyway In Your Browser

Full disclosure: ham radio isn’t for everyone, and there are many different facets to it. What appeals to one person might bore another to death. One area of ham radio that has changed a lot in the last few years is more or less local and typically mobile operation on VHF or UHF. Not long ago, hams used HTs (walky-talkies or handi-talkies) or mobile radios via repeaters to talk to each other and — the golden prize back then — make phone calls from their cars. Cell phones have made that much less interesting, but there is still an active community of operators talking on repeaters. However, the traffic has gone digital, the Internet is involved, and people with inexpensive, low-powered radios can talk to each other across the globe. This is nothing new, of course. However, having digital services means that operators with special interests can congregate in what amounts to radio chat rooms organized by region or topic.

There’s a long history of people listening to ham radio conversations with shortwave radios, SDRs, and scanners. But with so much activity now carried on the Internet, you can listen in using nothing more than your web browser or a phone app. I’ll show you how. If you get interested enough, it is easy enough to get your license. You don’t need any Morse code anymore, and a simple Technician class license in the United States is all you need to get going.

A Quick DMR Primer

There are several digital ham networks around and like real networks, you can have different physical transport layers and then build on top of that. For the purposes of this post, I’m going to focus on DMR (digital mobile radio) on the Brandmeister network which is very large and popular ham network. You won’t need a license nor will you need to sign up for anything as long as you are content to just listen.

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