From The Ashes: Coal Ash May Offer Rich Source Of Rare Earth Elements

March 19, 2025 by Dan Maloney 40 Comments

For most of history, the world got along fine without the rare earth elements. We knew they existed, we knew they weren’t really all that rare, and we really didn’t have much use for them — until we discovered just how useful they are and made ourselves absolutely dependent on them, to the point where not having them would literally grind the world to a halt.

This dependency has spurred a search for caches of rare earth elements in the strangest of places, from muddy sediments on the sea floor to asteroids. But there’s one potential source that’s much closer to home: coal ash waste. According to a study from the University of Texas Austin, the 5 gigatonnes of coal ash produced in the United States between 1950 and 2021 might contain as much as $8.4 billion worth of REEYSc — that’s the 16 lanthanide rare earth elements plus yttrium and scandium, transition metals that aren’t strictly rare earths but are geologically associated with them and useful in many of the same ways. Continue reading “From The Ashes: Coal Ash May Offer Rich Source Of Rare Earth Elements” →

Retrotechtacular: Ford Model T Wheels, Start To Finish

July 18, 2024 by Dan Maloney 20 Comments

There’s no doubt that you’ll instantly recognize clips from the video below, as they’ve been used over and over for more than 100 years to illustrate the development of the assembly line. But those brief clips never told the whole story about just how much effort Ford was forced to put into manufacturing just one component of their iconic Model T: the wheels.

An in-house production of Ford Motors, this film isn’t dated, at least not obviously. And with the production of Model T cars using wooden spoked artillery-style wheels stretching from 1908 to 1925, it’s not easy to guess when the film was made. But judging by the clothing styles of the many hundreds of men and boys working in the River Rouge wheel shop, we’d venture a guess at 1920 or so.

Production of the wooden wheels began with turning club-shaped spokes from wooden blanks — ash, at a guess — and drying them in a kiln for more than three weeks. While they’re cooking, a different line steam-bends hickory into two semicircular felloes that will form the wheel’s rim. The number of different steps needed to shape the fourteen pieces of wood needed for each wheel is astonishing. Aside from the initial shaping, the spokes need to be mitered on the hub end to fit snugly together and have a tenon machined on the rim end. The felloes undergo multiple steps of drilling, trimming, and chamfering before they’re ready to receive the spokes.

The first steel component is a tire, which rolls down out of a furnace that heats and expands it before the wooden wheel is pressed into it. More holes are drilled and more steel is added; plates to reinforce the hub, nuts and bolts to hold everything together, and brake drums for the rear wheels. The hubs also had bearing races built right into them, which were filled with steel balls right on the line. How these unsealed bearings were protected during later sanding and grinding operations, not to mention the final painting step, which required a bath in asphalt paint and spinning the wheel to fling off the excess, is a mystery.

Welded steel spoked wheels replaced their wooden counterparts in the last two model years for the T, even though other car manufacturers had already started using more easily mass-produced stamped steel disc wheels in the mid-1920s. Given the massive infrastructure that the world’s largest car manufacturer at the time devoted to spoked wheel production, it’s easy to see why. But Ford eventually saw the light and moved away from spoked wheels for most cars. We can’t help but wonder what became of the army of workers, but it probably wasn’t good. So turn the wheels of progress.

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Linux Fu: Alternative Shells

May 21, 2020 by Al Williams 38 Comments

On Unix — the progenitor of Linux — there was /bin/sh. It was simple, by comparison to today’s shells, but it allowed you to enter commands and — most importantly — execute lists of commands. In fact, it was a simple programming language that could make decisions, loop, and do other things to allow you to write scripts that were more than just a list of programs to run. However, it wasn’t always the easiest thing to use, so in true Unix fashion, people started writing new shells. In this post, I want to point out a few shells other than the ubiquitous bash, which is one of the successors to the old sh program.

Since the 7th Edition of Unix, sh was actually the Bourne shell, named after its author, Stephen Bourne. It replaced the older Thompson shell written in 1971. That shell had some resemblance to a modern shell, but wasn’t really set up for scripting. It did have the standard syntax for redirection and piping, though. The PWB shell was also an early contender to replace Thompson, but all of those shells have pretty much disappeared.

You probably use bash and, honestly, you’ll probably continue to use bash after reading this post. But there are a few alternatives and for some people, they are worth considering. Also, there are a few special-purpose shells you may very well encounter even if your primary shell is bash.

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Hacked AC And Ash Filter

August 14, 2010 by Mike Szczys 26 Comments

Moscow is in a bit of a hot spot right now, dealing with a heat wave and enormous wildfires. The combination of smoke, ash, and heat was driving Andrew up a wall so he built a contraption to provide some relief. It has two chambers, the bottom houses ice water, the top is an air baffle. A small DC fan pumps air into the upper chamber where it encounters the water being sprayed in from the lower reservoir. What results is a heat exchange similar to other diy AC setups we’ve seen. But Andrew also notes that after running the device for a while the smell of smoke and ash is gone. Can this setup be seen as an effective way to trap airborne smoke particles?