Mining And Refining: Uranium And Plutonium

April 24, 2024 by 40 Comments

When I was a kid we used to go to a place we just called “The Book Barn.” It was pretty descriptive, as it was just a barn filled with old books. It smelled pretty much like you’d expect a barn filled with old books to smell, and it was a fantastic place to browse — all of the charm of an old library with none of the organization. On one visit I found a stack of old magazines, including a couple of Popular Mechanics from the late 1940s. The cover art always looked like pulp science fiction, with a pipe-smoking father coming home from work to his suburban home in a flying car.

But the issue that caught my eye had a cover showing a couple of rugged men in a Jeep, bouncing around the desert with a Geiger counter. “Build your own uranium detector,” the caption implored, suggesting that the next gold rush was underway and that anyone could get in on the action. The world was a much more optimistic place back then, looking forward as it was to a nuclear-powered future with electricity “too cheap to meter.” The fact that sudden death in an expanding ball of radioactive plasma was potentially the other side of that coin never seemed to matter that much; one tends to abstract away realities that are too big to comprehend.

Things are more complicated now, but uranium remains important. Not only is it needed to build new nuclear weapons and maintain the existing stockpile, it’s also an important part of the mix of non-fossil-fuel electricity options we’re going to need going forward. And getting it out of the ground and turned into useful materials, including its radioactive offspring plutonium, is anything but easy.

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Hackaday Links: March 17, 2024

March 17, 2024 by 16 Comments

A friend of ours once described computers as “high-speed idiots.” It was true in the 80s, and it appears that even with the recent explosion in AI, all computers have managed to do is become faster. Proof of that can be found in a story about using ASCII art to trick a chatbot into giving away the store. As anyone who has played with ChatGPT or its moral equivalent for more than five minutes has learned, there are certain boundary conditions that the LLM’s creators lawyers have put in place to prevent discussion surrounding sensitive topics. Ask a chatbot to deliver specific instructions on building a nuclear bomb, for instance, and you’ll be rebuffed. Same with asking for help counterfeiting currency, and wisely so. But, by minimally obfuscating your question by rendering the word “COUNTERFEIT” in ASCII art and asking the chatbot to first decode the word, you can slip the verboten word into a how-to question and get pretty explicit instructions. Yes, you have to give painfully detailed instructions on parsing the ASCII art characters, but that’s a small price to pay for forbidden knowledge that you could easily find out yourself by other means.

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Keeping Track Of The Night Sky With Discrete Logic Chips

February 9, 2024 by 11 Comments

As hobbies go, stargazing has a pretty low barrier to entry. All you really need is a pair of Mark 1 eyeballs and maybe a little caffeine to help you stay up late enough. Astronomy, on the other hand, takes quite a bit more equipment, not least of which is a telescope and a way to get it pointed in the right direction at the right time, and to make up for the pesky fact that we’re on a moving, spinning ball of rock.

Yes, most of the equipment needed for real astronomy is commercially available, but [Mitsuru Yamada] decided to go his own way with this homebrew retro-style telescope motor controller. Dubbed MCT-6, the controller teams up with his dual-6502 PERSEUS-9 computer to keep his scope on target. There are a lot of literally moving parts to this build, including the equatorial mount which is made from machined aluminum and powered by a pair of off-the-shelf stepper-powered rotary stages for declination and right ascension. The controller that runs the motors is built completely from discrete 74HCxx logic chips that divide down a 7.0097-MHz crystal oscillator signal to drive the steppers precisely at one revolution per diurnal day. The pulse stream can also be sped up for rapid slewing, to aim the telescope at new targets using a hand controller.

As impressive as all this is, the real star (sorry) of the show here is the fit and finish. In typical [Yamada-san] fashion, the impeccably wire-wrapped mainboard fits in a robust die-cast aluminum case that fits the retro aesthetic of the whole project. The PERSEUS-9 is used mainly as a display and control terminal, running custom software to show where the telescope is pointed and calculate the coordinates of various heavenly bodies. As a bonus, the 40×7 alphanumeric red LED display should be easy on dark-adapted eyes.

Hats off to [Mitsuru Yamada] on another fabulous build. If you haven’t had enough of his build style yet, be sure to check out his PERSEUS-8 or even his foray into the analog world.

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Mining And Refining: Titanium, Our Youngest Industrial Metal

December 5, 2023 by 9 Comments

Earlier in this series, we made the case for copper being “the metal that built technology.” Some readers took issue with that statement, noting correctly that meteoric iron and gold were worked long before our ancestors were able to locate and exploit natural copper outcroppings, therefore beating copper to the historical punch. That seems to miss the point, though; figuring out how to fashion gold decorations and iron trinkets doesn’t seem like building the foundations for industry. Learning to make tools from copper, either pure or alloyed with tin to make bronze? Now that’s how you build an industrial base.

So now comes the time for us to make the case for our most recent addition to humanity’s stable of industrial metals: titanium. Despite having been discovered in 1791, titanium remained locked away inside abundantly distributed ores until the 1940s, when the technological demands of a World War coupled with a growing chemical prowess and command of sufficient energy allowed us to finally wrest the “element of the gods” from its minerals. The suddenness of it all is breathtaking, too; in 1945, titanium was still a fantastically expensive laboratory oddity, but just a decade later, we were producing it by the (still very expensive) ton and building an entirely new aerospace industry around the metal.

In this installment of “Mining and Refining,” we’ll take a look at titanium and see why it took us over 11,000 years to figure out how to put it to work for us.

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3D Human Models From A Single Image

November 20, 2023 by 12 Comments

You’ve seen it in movies and shows — the hero takes a blurry still picture, and with a few keystrokes, generates a view from a different angle or sometimes even a full 3D model. Turns out, thanks to machine learning and work by several researchers, this might be possible. As you can see in the video below, using “shape-guided diffusion,” the researchers were able to take a single image of a person and recreate a plausible 3D model.

Of course, the work relies on machine learning. As you’ll see in the video, this isn’t a new idea, but previous attempts have been less than stellar. This new method uses shape prediction first, followed by an estimate of the back view appearance. The algorithm then guesses what images go between the initial photograph and the back view. However, it uses the 3D shape estimate as a guideline. Even then,  there is some post-processing to join the intermediate images together into a model.

The result looks good, although the video does point out some areas where they still fall short. For example, unusual lighting can affect the results.

This beats spinning around a person or a camera to get many images. Scanning people in 3D is a much older dream than you might expect.

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Chugging Along: A Steam-Powered Sawmill Still Makes Its Mark

October 31, 2023 by 11 Comments

[Rural Heritage TV] has video of a private tour of a working, two-story, steam-powered sawmill at Lake Itasca, Minnesota. This is believed to be one of the only working steam-powered band-sawmills in the country with a shotgun (or reciprocating) feed carriage. The carriage moves back and forth with a log while a monstrous 44-foot long bandsaw cuts pieces off on every stroke. There’s even a log turning mechanism, because if there’s one thing that never changes, it’s that time is money.

There is great footage of the whole thing in action, and also a serious tour of just how much work was needed to keep such a tool running. For example, in its heyday a machine like this would be swapping bands out for maintenance and sharpening every few hours.

Viewers unfamiliar with such machinery may notice the lack of rims or guard rails on the bandsaw and other belts and pulleys. How do bands stay centered on spinning wheels without falling off? The crowned pulley was the steam era’s solution, providing a means for belts to self-center without any need for rims or other additions.

This tour of the sawmill is a nifty peek at a technology that, at one point, ruled the roost. Watch it in action in the video, just under the page break. If that leaves you hungry to know more, there’s a second video that goes into added detail about saw sharpening and more.

One last tip: if you’re hungry to know more about the history of the steam engine, The Perfectionists is absolutely a book you should read because it goes into fascinating detail about that, and more.

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Tech In Plain Sight: Microwave Ovens

September 26, 2023 by 31 Comments

Our homes are full of technological marvels, and, as a Hackaday reader, we are betting you know the basic ideas behind a microwave oven even if you haven’t torn one apart for transformers and magnetrons. So we aren’t going to explain how the magnetron rotates water molecules to produce uniform dielectric heating. However, when we see our microwave, we think about two things: 1) this thing is one of the most dangerous things in our house and 2) what makes that little turntable flip a different direction every time you run the thing?

First, a Little History

Westinghouse Powercaster which could, among other things, toast bread in six seconds

People think that Raytheon engineer Percy Spenser, the chief of their power tube division, noticed that while working with a magnetron he found his candy bar had melted. This is, apparently, true, but Spenser wasn’t the first to notice. He was, however, the first to investigate it and legend holds that he popped popcorn and blew up an egg on a colleague’s face (this sounds like an urban legend about “egg on your face” to us). The Raytheon patent goes back to 1945.

However, cooking with radio energy was not a new idea. In 1933, Westinghouse demonstrated cooking foods with a 10 kW 60 MHz transmitter (jump to page 394). According to reports, the device could toast bread in six seconds.  The same equipment could beam power and — reportedly — exposing yourself to the field caused “artificial fever” and an experience like having a cocktail, including a hangover on overindulgence. In fact, doctors would develop radiothermy to heat parts of the body locally, but we don’t suggest spending an hour in the device.

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