POP! Goes The Hydrogen Howitzer

Military models are great 3D printing projects, even more so if they are somewhat functional. [Flasutie] took it a step further by engineering a 3D-printed howitzer that doesn’t just sit pretty—it launches shells with a hydrogen-powered bang.

This project’s secret sauce? Oxyhydrogen, aka HHO, the mix of hydrogen born when water endures the electric breakup of electrolysis. [Flasutie] wanted functional “high explosive” (HE) projectiles to pop without turning playtime into emergency room visit, and 30 mm was the magic size, allowing the thin-walled PLA projectile to rupture without causing injury, even when held in the hand. To set off the gaseous fireworks, [Flasutie] designed an impact fuze featuring piezoelectric spark mechanism nestled within a soft TPU tip for good impact sensitivity.

The howitzer itself is like something out of a miniaturized military fantasy—nearly entirely 3D printed. It boasts an interrupted thread breech-locking mechanism and recoil-absorbing mechanism inspired by the real thing. The breechblock isn’t just for show; it snaps open under spring power and ejects spent cartridges like hot brass.

Watch the video after the break for the build, satisfying loading sequence and of course cardboard-defeating “armor piercing” (AP) and HE shells knocking out targets.

Aqueous Battery Solves Lithium’s Problems

The demand for grid storage ramps up as more renewable energy sources comes online, but existing technology might not be up to the challenge. Lithium is the most popular option for battery storage right now, not just due to the physical properties of the batteries, but also because we’re manufacturing them at a massive scale already. Unfortunately they do have downsides, especially with performance in cold temperatures and a risk of fires, which has researchers looking for alternatives like aqueous batteries which mitigate these issues.

An aqueous battery uses a water-based electrolyte to move ions from one electrode to the other. Compared to lithium, which uses lithium salts for the electrolyte, this reduces energy density somewhat but improves safety since water is much less flammable. The one downside is that during overcharging or over-current situations, hydrogen gas can be produced by electrolysis of the water, which generally needs to be vented out of the battery. This doesn’t necessarily damage the battery but can cause other issues. To avoid this problem, researchers found that adding a manganese oxide to the battery and using palladium as a catalyst caused any hydrogen generated within the battery’s electrolyte to turn back into water and return to the electrolyte solution without issue.

Of course, these batteries likely won’t completely replace lithium ion batteries especially in things like EVs due to their lower energy density. It’s also not yet clear whether this technology, like others we’ve featured, will scale up enough to be used for large-scale applications either, but any solution that solves some of the problems of lithium, like the environmental cost or safety issues, while adding more storage to an increasingly renewable grid, is always welcome.

Renewable Energy: Beyond Electricity

Perhaps the most-cited downside of renewable energy is that wind or sunlight might not always be available when the electrical grid demands it. As they say in the industry, it’s not “dispatchable”. A large enough grid can mitigate this somewhat by moving energy long distances or by using various existing storage methods like pumped storage, but for the time being some amount of dispatchable power generation like nuclear, fossil, or hydro power is often needed to backstop the fundamental nature of nature. As prices for wind and solar drop precipitously, though, the economics of finding other grid storage solutions get better. While the current focus is almost exclusively dedicated to batteries, another way of solving these problems may be using renewables to generate hydrogen both as a fuel and as a means of grid storage. Continue reading “Renewable Energy: Beyond Electricity”

Implant Fights Diabetes By Making Insulin And Oxygen

Type 1 diabetes remains a problem despite having an apparently simple solution: since T1D patients have lost the cells that produce insulin, it should be possible to transplant those cells into their bodies and restore normal function. Unfortunately, it’s not actually that simple, and it’s all thanks to the immune system, which would attack and destroy transplanted pancreas cells, whether from a donor or grown from the patient’s own stem cells.

That may be changing, though, at least if this implantable insulin-producing bioreactor proves successful.  The device comes from MIT’s Department of Chemical Engineering, and like earlier implants, it relies on encapsulating islet cells, which are the insulin-producing cells within the pancreas, inside a semipermeable membrane. This allows the insulin they produce to diffuse out into the blood, and for glucose, which controls insulin production in islet cells, to diffuse in. The problem with this arrangement is that the resource-intensive islet cells are starved of oxygen inside their capsule, which is obviously a problem for the viability of the implant.

The solution: electrolysis. The O2-Macrodevice, as the implant is called, uses a tiny power-harvesting circuit to generate oxygen for the islet cells directly from the patient’s own interstitial water. The circuit applies a current across a proton-exchange membrane, which breaks water molecules into molecular oxygen for the islet cells. The hydrogen is said to diffuse harmlessly away; it seems like that might cause an acid-base imbalance locally, but there are plenty of metabolic pathways to take care of that sort of thing.

The implant looks promising; it kept the blood glucose levels of diabetic mice under control, while mice who received an implant with the oxygen-generating cell disabled started getting hyperglycemic after two weeks. What’s really intriguing is that the study authors seem to be thinking ahead to commercial production, since they show various methods for mass production of the cell chamber from standard 150-mm silicon wafers using photolithography.

Type 1 diabetics have been down the “artificial pancreas” road before, so a wait-and-see approach is clearly wise here. But it looks like treating diabetes less like a medical problem and more like an engineering problem might just pay dividends.

Creating An Automated Hydrogen Generator At Home

Everyone and their pet hamster probably knows that the most common way to produce hydrogen is via the electrolysis of water, but there are still a number of steps between this elementary knowledge and implementing a (mostly) automated hydrogen generator. Especially if your end goal is to create liquid hydrogen when everything is said and done. This is where [Hyperspace Pirate]’s latest absolutely not dangerous project commences, with the details covered in the recently published video.

Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]'s dog drinking bowl.
Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]’s dog drinking bowl.
Since electrolysis cannot occur with pure water, sodium hydroxide (NaOH) is used in the solution to provide the ions. The electrodes are made of 316 stainless steel, mostly because this is cheap and good enough for this purpose. Although the original plan was to use a stacked series of electrodes with permeable membranes like in commercial electrolysers, this proved to be too much of a hassle to seal up leak-tight. Ergo the demonstrated version was attempted, where an upturned glass bell provides the barrier for the produced hydrogen and oxygen. With this system it’s easy to measure the volume of the produced hydrogen due to the displaced water in the bell.

Once enough hydrogen gas is produced, a vacuum pump is triggered by a simple pair of electrodes to move the hydrogen gas to a storage container. Due to hydrogen embrittlement concerns, an aluminium tank was used rather than a steel one. Ultimately enough hydrogen gas was collected to fill a lot of party balloons, and with the provided information in the video it should be quite straightforward to reproduce the system.

Where the automation comes into play is with a control system that monitors for example how long the vacuum pump has been running, and triggers a fail safe state if it’s more than a set limit. With the control system in place, [Hyperspace Pirate] was able to leave the hydrogen generator running for hours with no concerns. We’re hopeful that his upcoming effort to liquify this hydrogen will be as successful, or the human-rated blimp, or whatever all this hydrogen will be used for.

Continue reading “Creating An Automated Hydrogen Generator At Home”

Lighting Up With Chemistry, 1823-Style

With our mass-produced butane lighters and matches made in the billions, fire is never more than a flick of the finger away these days. But starting a fire 200 years ago? That’s a different story.

One method we’d never heard of was Döbereiner’s lamp, an 1823 invention by German chemist Johann Wolfgang Döbereiner. At first glance, the device seems a little sketchy, what with a tank of sulfuric acid and a piece of zinc to create a stream of hydrogen gas ignited by a platinum catalyst. But as [Marb’s Lab] shows with the recreation in the video below, while it’s not exactly as pocket-friendly as a Zippo, the device actually has some inherent safety features.

[Marb]’s version is built mainly from laboratory glassware, with a beaker of dilute sulfuric acid — “Add acid to water, like you ought-er!” — bathing a chunk of zinc on a fixed support. An inverted glass funnel acts as a gas collector, which feeds the hydrogen gas to a nozzle through a pinch valve. The hydrogen gas never mixes with oxygen — that would be bad — and the production of gas stops once the gas displaces the sulfuric acid below the level of the zinc pellet. It’s a clever self-limiting feature that probably contributed to the commercial success of the invention back in the day.

To produce a flame, Döbereiner originally used a platinum sponge, which catalyzed the reaction between hydrogen and oxygen in the air; the heat produced by the reaction was enough to ignite the mixture and produce an open flame. [Marb] couldn’t come up with enough of the precious metal, so instead harvested the catalyst from a lighter fluid-fueled hand warmer. The catalyst wasn’t quite enough to generate an open flame, but it glowed pretty brightly, and would be more than enough to start a fire.

Hats off to [Marb] for the great lesson is chemical ingenuity and history. We’ve seen similar old-school catalytic lighters before, too.

Continue reading “Lighting Up With Chemistry, 1823-Style”

Toyota Makes Grand Promises On Battery Tech

Toyota is going through a bit of a Kodak moment right now, being that like the film giant they absolutely blundered the adoption of a revolutionary technology. In Kodak’s case it was the adoption of the digital camera which they nearly completely ignored; Toyota is now becoming similarly infamous for refusing to take part in the electric car boom, instead placing all of their faith in hybrid drivetrains and hydrogen fuel cell technologies. Whether or not Toyota can wake up in time to avoid a complete Kodak-style collapse remains to be seen, but they have been making some amazing claims about battery technology that is at least raising some eyebrows. Continue reading “Toyota Makes Grand Promises On Battery Tech”