Boss Byproducts: Fulgurites Are Fossilized Lightning

October 29, 2024 by Kristina Panos 28 Comments

So far in this series, we’ve talked about man-made byproducts — Fordite, which is built-up layers of cured car enamel, and Trinitite, which was created during the first nuclear bomb test.

A fulgurite pendant. — A lovely fulgurite pendant. Image via Etsy

But not all byproducts are man-made, and not all of them are basically untouchable. Some are created by Mother Nature, but are nonetheless dangerous. I’m talking about fulgurites, which can form whenever lightning discharges into the Earth.

It’s likely that even if you’ve seen a fulgurite, you likely had no idea what it was. So what are they, exactly? Basically, they are natural tubes of glass that are formed by a fusion of silica sand or rock during a lightning strike.

Much like Lichtenberg figures appear across wood, the resulting shape mimics the path of the lightning bolt as it discharged into the ground. And yes, people make jewelry out of fulgurites.

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A Homebrew Gas Chromatograph That Won’t Bust Your Budget

October 13, 2024 by Dan Maloney 17 Comments

Chances are good that most of us will go through life without ever having to perform gas chromatography, and if we do have the occasion to do so, it’ll likely be on a professional basis using a somewhat expensive commercial instrument. That doesn’t mean you can’t roll your own gas chromatograph, though, and if you make a few compromises, it’s not even all that expensive.

At its heart, gas chromatography is pretty simple; it’s just selectively retarding the movement of a gas phase using a solid matrix and measuring the physical or chemical properties of the separated components of the gas as they pass through the system. That’s exactly what [Markus Bindhammer] has accomplished here, in about the simplest way possible. Gas chromatographs generally use a carrier gas such as helium to move the sample through the system. However, since that’s expensive stuff, [Markus] decided to use room air as the carrier.

The column itself is just a meter or so of silicone tubing packed with chromatography-grade silica gel, which is probably the most expensive thing on the BOM. It also includes an injection port homebrewed from brass compression fittings and some machined acrylic blocks. Those hold the detectors, an MQ-2 gas sensor module, and a thermal conductivity sensor fashioned from the filament of a grain-of-wheat incandescent lamp. To read the sensors and control the air pump, [Markus] employs an Arduino Uno, which unfortunately doesn’t have great resolution on its analog-to-digital converter. To fix that, he used the ubiquitous HX7111 load cell amplifier to read the output from the thermal conductivity sensor.

After purging the column and warming up the sensors, [Markus] injected a sample of lighter fuel and exported the data to Excel. The MQ-2 clearly shows two fractions coming off the column, which makes sense for the mix of propane and butane in the lighter fuel. You can also see two peaks in the thermal conductivity data from a different fuel containing only butane, corresponding to the two different isomers of the four-carbon alkane.

[Markus] has been on a bit of a tear lately; just last week, we featured his photochromic memristor and, before that, his all-in-one electrochemistry lab.

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Memristors Are Cool, Radiation-resistant Memristors Even Moreso

October 5, 2024 by Donald Papp 9 Comments

Space is a challenging environment for semiconductors, but researchers have shown that a specific type of memristor (the hafnium oxide memristor, to be exact) actually reacts quite usefully when exposed to gamma radiation. In fact, it’s even able to leverage this behavior as a way to measure radiation exposure. In essence, it’s able to act as both memory and a sensor.

Being able to resist radiation exposure is highly desirable for space applications. Efficient ways to measure radiation exposure are just as valuable. The hafnium oxide memristor looks like it might be able to do both, but before going into how that works, let’s take a moment for a memristor refresher.

A memristor is essentially two conductive plates between which bridges can be made by applying a voltage to “write” to the device, by which one sets it to a particular resistance. A positive voltage causes bridging to occur between the two ends, lowering the device’s resistance, and a negative voltage reverses the process, increasing the resistance. The exact formulation of a memristor can vary. The memristor was conceived in the 1970s by Leon Chua, and HP Labs created a working one in 2008. An (expensive) 16-pin DIP was first made available in 2015.

A hafnium oxide memristor is a bit different. Normally it would be write-once, meaning a negative voltage does not reset the device, but researchers discovered that exposing it to gamma radiation appears to weaken the bridging, allowing a negative voltage to reset the device as expected. Exposure to radiation also caused a higher voltage to be required to set the memristor; a behavior researchers were able to leverage into using the memristor to measure radiation exposure. Given time, a hafnium oxide memristor exposed to radiation, causing it to require higher-than-normal voltages to be “set”, eventually lost this attribute. After 30 days, the exposed memristors appeared to recover completely from the effects of radiation exposure and no longer required an elevated voltage for writing. This is the behavior the article refers to as “self-healing”.

The research paper has all the details, and it’s interesting to see new things relating to memristors. After all, when it comes to electronic components it’s been quite a long time since we’ve seen something genuinely new.

Little Pharma On The Prairie

September 24, 2024 by Brian McEvoy 53 Comments

Let’s get the obvious out of the way first — in his DEFCON 32 presentation, [Dr. Mixæl Laufer] shared quite a bit of information on how individuals can make and distribute various controlled substances. This cuts out pharmaceutical makers, who have a history of price-gouging and discontinuing recipes that hurt their bottom line. We predict that the comment section will be incendiary, so if your best argument is, “People are going to make bad drugs, so no one should get to have this,” please disconnect your keyboard now. You would not like the responses anyway.

Let’s talk about the device instead of policy because this is an article about an incredible machine that a team of hackers made on their own time and dime. The reactor is a motorized mixing vessel made from a couple of nested Mason jars, surrounded by a water layer fed by hot and cold reservoirs and cycled with water pumps. Your ingredients come from three syringes and three stepper-motor pumps for accurate control. The brains reside inside a printable case with a touchscreen for programming, interaction, and alerts.

It costs around $300 USD to build a MicroLab, and to keep it as accessible as possible, it can be assembled without soldering. Most of the cost goes to a Raspberry Pi and three peristaltic pumps, but if you shop around for the rest of the parts, you can deflate that price tag significantly. The steps are logical, broken up like book chapters, and have many clear pictures and diagrams. If you want to get fancy, there is room to improvise and personalize. We saw many opportunities where someone could swap out components, like power supplies, for something they had lying in a bin or forego the 3D printing for laser-cut boards. The printed pump holders spell “HACK” when you disassemble them, but we would have gone with extruded aluminum to save on filament.

Several times [⁨Mixæl] brings up the point that you do not have to be a chemist to operate this any more than you have to be a mechanic to drive a car. Some of us learned about SMILES (Simplified Molecular Input Line Entry System) from this video, and with that elementary level of chemistry, we feel confident that we could follow a recipe, but maybe for something simple first. We would love to see a starter recipe that combines three sodas at precise ratios to form a color that matches a color swatch, so we know the machine is working correctly; a “calibration cocktail,” if you will.

If you want something else to tickle your chemistry itch, check out our Big Chemistry series or learn how big labs do automated chemistry.

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A person examines a diamond with a loupe.

We’ll Take DIY Diamond Making For $200,000

September 16, 2024 by Kristina Panos 12 Comments

They say you can buy anything on the Internet if you know the right places to go, and apparently if you’re in the mood to make diamonds, then Alibaba is the spot. You even have your choice of high-pressure, high-temperature (HPHT) machine for $200,000, or a chemical vapor deposition (CVD) version, which costs more than twice as much. Here’s a bit more about how each process works.

A sea of HPHT diamond-making machines. — A sea of HPHT machines. Image via Alibaba

Of course, you’ll need way more than just the machine and a power outlet. Additional resources are a must, and some expertise would go a long way. Even so, you end up with raw diamonds that need to be processed in order to become gems or industrial components.

For HPHT, you’d also need a bunch of good graphite, catalysts such as iron and cobalt, and precise control systems for temperature and pressure, none of which are included as a kit with the machine.

For CVD, you’d need methane and hydrogen gases, and precise control of microwaves or hot filaments. In either case, you’re not getting anywhere without diamond seed crystals.

Right now, the idea of Joe Hacker making diamonds in his garage seems about as far off as home 3D printing did in about 1985. But we got there, didn’t we? Hey, it’s a thought.

Main and thumbnail images via Unsplash

An Earth-Bound Homage To A Martian Biochemistry Experiment

September 14, 2024 by Dan Maloney 5 Comments

With all the recent attention on Mars and the search for evidence of ancient life there, it’s easy to forget that not only has the Red Planet been under the figurative microscope since the early days of the Space Race, but we went to tremendous effort to send a pair of miniaturized biochemical laboratories there back in 1976. While the results were equivocal, it was still an amazing piece of engineering and spacefaring, one that [Marb] has recreated with this Earth-based version of the famed Viking “Labeled Release” experiment.

The Labeled Release experimental design was based on the fact that many metabolic processes result in the evolution of carbon dioxide gas, which should be detectable by inoculating a soil sample with a nutrient broth laced with radioactive carbon-14. For this homage to the LR experiment, [Marb] eschewed the radioactive tracer, instead looking for a relative increase in the much lower CO₂ concentration here on Earth. The test chamber is an electrical enclosure with a gasketed lid that holds a petri dish and a simple CO₂ sensor module. Glands in the lid allow an analog for Martian regolith — red terrarium sand — and a nutrient broth to be added to the petri dish. Once the chamber was sterilized, or at least sanitized, [Marb] established a baseline CO₂ level with a homebrew data logger and added his sample. Adding the nutrient broth — a solution of trypsinized milk protein, yeast extract, sugar, and salt — gives the bacteria in the “regolith” all the food they need, which increases the CO₂ level in the chamber.

More after the break…

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Building A Multi-Purpose Electrochemistry Device

September 13, 2024 by Dave Rowntree 12 Comments

We don’t get enough electrochemistry hacks on these pages, so here’s [Markus Bindhammer] of YouTube/Marb’s lab fame to give us a fix with their hand-built general-purpose electrochemistry device.

The basic structure is made from plyboard cut to size on a table saw and glued’n’screwed together. The top and front are constructed from an aluminium sheet bent to shape with a hand-bender. A laser-printed front panel finishes the aesthetic nicely, contrasting with the shiny aluminium. The electrode holders are part of off-the-shelf chemistry components, with the electrical contacts hand-made from components usually used for constructing stair handrails. Inside, a 500 RPM 12 V DC geared motor is mounted, driving a couple of small magnets. A PWM motor speed controller provides power. This allows a magnetic stirrer to be added for relevant applications. Power for the electrochemical cell is courtesy of a Zk-5KX buck-boost power supply with a range of 0 – 36 V at up to 5 A with both CV and CC modes. A third electrode holder is also provided as a reference electrode for voltammetry applications. A simple and effective build, we reckon!

Over the years, we’ve seen a few electrochemical hacks, like this DIY electroplating pen, a DIY electrochemical machining rig, and finally, a little something about 3D printing metal electrochemically.

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