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140 Articles

Retrotechtacular: The Other Kind Of Fallout Show

April 16, 2024 by 28 Comments

Thanks to the newly released Amazon Prime series, not to mention nearly 30 years as a wildly successful gaming franchise, Fallout is very much in the zeitgeist these days. But before all that, small-F fallout was on the minds of people living in countries on both sides of the Iron Curtain who would have to deal with the aftermath of a nuclear exchange.

“Uwaga! Pył promieniotwórczy“  (“Beware! Radioactive Dust”) is a 1965 Polish civil defense film from film studio Wytwórnia Filmów Oświatowych. While the Cold War turning hot was not likely to leave any corner of the planet unscathed, Poland was certainly destined to bear the early brunt of a nuclear exchange between the superpowers, and it was clear that the powers that be wanted to equip any surviving Polish people with the tools needed to deal with their sudden change in circumstances.

The film, narrated in Polish but with subtitles in English, seems mainly aimed at rural populations and is mercifully free of the details of both fallout formation and the potential effects of contact with radioactive dust, save for a couple of shots of what looks like a pretty mild case of cutaneous radiation syndrome.

Defense against fallout seems focused on not inhaling radioactive dust with either respirators or expedient facemasks, and keeping particles outside the house by wearing raincoats and boots, which can be easily cleaned with water. The fact that nowhere in the film is it mentioned that getting fallout on your clothes or in your lungs could be largely avoided by not going outside is telling; farmers really can’t keep things running from the basement.

A lot of time in this brief film is dedicated to preventing food and water from becoming contaminated, and cleaning it off if it does happen to get exposed. We thought the little tin enclosures over the wells were quite clever, as were the ways to transfer water from the well to the house without picking up any contamination. The pros and cons of different foods are covered too — basically, canned foods dobry, boxed foods zły. So, thumbs up for Cram, but you might want to skip the YumYum deviled eggs.

Dealing with the potential for a nuclear apocalypse is necessarily an unpleasant subject, and it’s easy to dismiss the advice of the filmmakers as quaint and outdated, or just an attempt to give the Polish people a sense of false hope. And that may well be, but then again, giving people solid, practical steps they can take will at least give them some agency, and that’s rarely a bad thing.

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Building A Tiny Organic Swimming Pool With Natural Filtering

March 24, 2024 by 18 Comments

When we think of swimming pools, we typically think of large fiberglass, plastic, or concrete constructions full of pristine, clear water. They’re usually maintained in this state with the regular addition of chlorine or other chemical. These kill biological stuff and help filter out dirt and other detritus. However,  [David] likes to do things differently, as he demonstrates with a tiny plunge pool built inside his greenhouse.

The basic construction starts with digging a hole and building up a wall with concrete and bricks. There’s nothing particularly controversial there. It’s roughly 2 meters by 3 meters by 0.8 meters deep. To help the pool maintain heat, there’s a layer of foam insulation in the bottom, while the water is held inside a black liner.

Rather than traditional chemical methods, however, [David] relies on organic methods to maintain the pool. He explains how he uses an aquarium pump to create a “bubble filtered” pool that draws water through a gravel bed to maintain it and keep it clear. It’s a very natural setup, with multiple plants in the water to make it as organic as can be. It’s the kind of thing you’d expect to see at a luxury island resort, but [David’s] got one right in his very own greenhouse.  [David] explains the organic filtering concept in greater detail on his website.

We’ve featured some pool hacks before, too, though more traditional ones than this. Video after the break.

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A series of plates and tubes sits in a tank of water. The plates are square with what looks to be a white coating.

Desalinating Water With The Sun

December 21, 2023 by 12 Comments

Getting fresh water from salt water can be difficult to do at any kind of scale. Researchers have developed a new method of desalinating water that significantly reduces its cost. [via Electrek]

By mimicking the thermohaline circulation of the ocean, the researchers from MIT and Shanghai Jiao Tong University were able to solve one of the primary issues with desalination systems, salt fouling. Using a series of evaporator/condenser stages, the seawater is separated into freshwater and salt using heat from the sun.

Evaporating water to separate it from salt isn’t new, but the researchers took it a step further by tilting the whole contraption and introducing a series of tubes to help move the water along and create eddy currents. These currents help the denser, saltier water move off of the apparatus and down deeper into the fluid where the salt doesn’t cause an issue with the device’s operation. The device should have a relatively long lifetime since it has no moving parts and doesn’t require any electricity to operate.

The researchers believe a small, suitcase-sized device could produce water for a family for less than the cost of tap water in the US. The (paywalled) paper is available from Joule.

If you’re curious about other drinking water hacks, check out this post on Re-Imagining the Water Supply or this previous work by the same researchers.

Re-imagining The Water Supply

October 15, 2023 by 49 Comments

Getting freshwater supplied across cities and towns in a reliable and safe way is no simple task. Not only is a natural freshwater reservoir or other supply needed, but making sure the water is safe to drink and then shipping it out over a dense network of pumps and pipes can cost a surprising amount of time and money. It also hinges on a reliable power grid, which is something Texas resident [Suburban Biology] doesn’t have. But since fresh water literally falls out of the sky for free, he decided to take this matter into his own hands.

The main strategy with a system like this is to keep the rainwater as clean as possible before storage so that expensive treatment systems are less necessary. That means no asphalt shingles, a way to divert the first bit of rain that washes dust and other contaminants off the roof away, and a safe tank. This install uses a 30,000 gallon tank placed above ground for storage, but that’s not the only thing that goes into a big rainwater catchment system like this. A system of PVC pipes are needed both for sending rainwater from the roofs of the buildings into the tank and for pumping it into the home for use. With all of that in place it’s both a hedge against climate change, unstable electric grids, and even separates the user from the local aquifer which may or may not have its own major issues depending on where you live.

While Texas legally protects the rights of citizens to collect and store rainwater, the same isn’t true for all areas. For example, Colorado only just passed a law allowing the collection and storage of a meager 110 gallons of rainwater and forbade it entirely beforehand. There are some other considerations for a project like this too, largely that above-ground systems generally won’t work in cold climates. On the other hand, large systems like these are really only needed where rainfall is infrequent; in more tropical areas like south Florida a much smaller storage system can be used

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The Science Behind The Majesty Of Dancing Raisins

September 16, 2023 by 18 Comments

Have you ever thrown a handful of raisins into a tub of sparkling water? Or peanuts into beer? It seems like an altogether strange thing to do, but if you’ve tried it, you’ll have seen the way the raisins dance and tumble in the fluid. As it turns out, there’s some really interesting science at play when you dive into the mechanics of it all. [Saverio Spagnolie] did just that, and even went as far as publishing a paper on the topic.

The fundamental mechanism behind the dancing raisins is down to the bubbles in sparkling water. When dropped into the fluid, bubbles form on the raisins and attach to them, giving them additional buoyancy.  They then float up, with some of the bubbles shedding or popping on the way, others doing so at the fluid surface. This then causes the raisins to lose buoyancy, rotate, flop around, and generally dance for our amusement.

[Saverio] didn’t just accept things at face value though, and started taking measurements. He used 3D-printed models to examine bubble formation and the forces involved. Along with other scientists, models were developed to explore bubble formation, shedding, and the dynamics of raisin movement. If you don’t have time to dive into the paper, [Saverio] does a great job of explaining it in a Twitter thread (Nitter) in an accessible fashion.

It’s a great example of cheap kitchen science that can teach you all kinds of incredible physics if you just care to look. Video after the break.

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Clean Water, From A Plant-Based Filter

September 9, 2023 by 20 Comments

If you’re an outdoors person, one of the earliest things you learned was probably that in-field water sources can’t always be trusted as drinkable. A clear mountain stream could have a dead sheep in it just upstream, for example. Maybe you learned to boil it, or perhaps add chemical tablets. Up-to-date campers have a range of filters at their disposal thanks to nanotechnology, but such devices aren’t the only options to avoid sickness. [BeraAjan] has built one using plant xylem.

The inspiration for this filter came from an MIT paper, and the plant xylem in question isn’t the thin layer we were expecting but a far thicker one found in young conifer branches. In fact, the whole twig without its bark is placed in a tube, and the water filters through it.

It’s fair to say that this isn’t the fastest of filters though, as you can see in the video below the break. He’s combined a few individual filters, but maybe it’s not for the easily bored.

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A series of trapezoidal steel "buckets" attached together to form a metal water wheel. They are arranged around a square center frame that attaches to a hub for the wheel to spin about. The wheel is next to a stream and four people of various ages appear to be talking around it. A cinder block building with a metal roof is in the left background, and an older, yellow stone building is far off in the distance on the right of the image. The landscape is lush, green, and mountainous.

Open Source Waterwheel

August 20, 2023 by 28 Comments

Here in the West, power going out is an unusual event. But in more remote regions like the Himalayas, reliable electricity isn’t a given. A group of local craftspeople, researchers, and operators in Nepal have worked together to devise a modular waterwheel system.

Based on a 20-30 cm-wide bucket module consisting of only four galvanized steel components, the wheels can be easily built and deployed using resources and tools that are easy to find anywhere in the world. Current test devices generate between 120 and 1,400 Watts of power, depending on the device’s size.

A software tool was also developed that takes the head and flow rate of a location as inputs to calculate the dimensions of the optimal wheel and expected power output for an installation. This lets communities find ideal sites for power generation and calculate the expected costs.

We’ve covered a few other DIY hydropower setups, from repurposed washing machines to custom scratch builds.