We don’t know why, but for some reason, the more dangerous something is, the more hacker appeal it seems to have. We like to deal with high temperatures, high voltages, dangerous chemicals, and powerful lasers. So [Tech Ingredient’s] recent video about homemade rocket motors certainly caught our attention. You may need a little commitment, though. The first video (yes, there isn’t just one) is over an hour long.
Turns out, [Tech] doesn’t actually want to use the rockets for propulsion. He needed a source of highly-ionized high-velocity plasma to try to get more power from his magnetohydrodynamic project. Whatever you want to use it for, these are serious-sized motors. [Tech] claims that his design is both powerful and easy to build. He also has a “secret” rocket fuel that he shares. What is it? We won’t spoil the video for you, but it is a sweet surprise.
Like most of us, [Clem] wants to 3D print in metal. Metal 3D printers do exist, but they are generally way out of reach for most of us garage hackers. As an alternative, [Clem] uses a homebrew electroplating system to get prints with a metallic coating.
The setup is quite simple. Small glass jars to act as the plating tanks and the machine uses an Arduino controller along with a PCB to hold things like a relay to control the 24V used for electroplating. To keep everything tidy, [Clem] designed a 3D printed box that stores all the cables and chemicals when you aren’t using them. Since the parts might get hot, the plastic is PETG.
The trick is that parts need to be conductive in order to use electroplating — typically plastic isn’t conductive. [Clem] paints the plastic parts to grant them conductivity. Graphite paint didn’t give great results. However, an iron-based paint worked better but obscures detail on the print. In addition to galvanization (plating with zinc or steel) you can see copper plating of a nail at around the 12 minute mark, with a plastic plating demo a minute later. The machine can even plate gold using an expensive gold-bearing electrolyte. In the video comments, someone also mentioned that it would be interesting to try plating conductive filament without using the paint. [Clem] tried to remove rust from a big part, but the power supply wasn’t up to the task.
Copper plating is often used as a step to make a part conductive so you can then plate with another metal. In addition to copper sulfate, you can use copper acetate. Sometimes, getting metal into fine details can be tough and it is easier to use a pen to plate those areas directly.
Who doesn’t love epoxy? Epoxy resins, also known as polyepoxides, are an essential adhesive in many applications, both industrially and at smaller scales. Many polyepoxides however require the application of heat (around 150 °C for most types) in order to cure (harden), which can be complicated when the resin is applied to or inside layers of temperature sensitive materials. Now researchers at Nanyang Technological University (NTU) in Singapore have found a way to heat up resins using an alternating magnetic field (PDF), so-called magnetocuring.
As detailed in the research article by R. Chaudhary et al., they used commercially available epoxy resin and added nano particles of a MnxZn1-xFe2O4 alloy. This mixture was exposed to an alternating magnetic field to induce currents in the nano particles and subsequently produce heat that served to raise the temperature of the surrounding resin to about 160 °C in five minutes, allowing the resin to cure. There is no risk of overheating, as the nano particles are engineered to reach their Curie temperature, at which point the magnetic field no longer affects them. The exact Curie temperature was tweaked by changing the amount of manganese and zinc in the alloy.
After trying out a number of different alloy formulations, they settled on Mn0.7Zn0.3Fe2O4 as the optimal formulation at which no resin scorching occurred. As with all research it’s hard to tell when (and if) it will make it into commercial applications, but if this type of technology works out we could soon be gluing parts together using epoxy resin and an EM field instead of fumbling with the joys of two-component epoxy.
As the world waits for COVID-19 vaccines, some pharmaceutical companies stand armed and ready with an exciting improvement: better vials to hold the doses. Vials haven’t changed much in the last 100 years, but in 2011, Corning decided to do something about that. They started developing an alternative glass that is able to resist damage and prevent cracks. It’s called Valor glass, and it’s amazingly strong stuff. Think Gorilla glass for the medical industry.
Traditionally, pharmaceutical vials have been made from borosilicate glass, which is the same laboratory-safe material as Corning’s Pyrex. Borosilicate glass gets its strength from the addition of boron. Although borosilicate glass is pretty tough, it comes with some issues. Any type of glass is only as strong as its flaws, and borosilicate glasses are prone to some particularly strength-limiting flaws. Pharmaceutical glass must stand up to extreme temperatures, from the high heat of the vial-making process to the bitterly cold freeze-drying process and storing temperature required by the fragile viral RNA of some COVID-19 vaccines. Let’s take a look at how Valor glass vials tackle these challenges.
How exactly does salt help? The very fine salt coating deposited on the fibers of a mask’s filtration layer first dissolves on contact with airborne pathogens, then undergoes evaporation-induced recrystallization. Pathogens caught in the filter are therefore exposed to an increasingly-high concentration saline solution and are then physically damaged. There is a bit of a trick to getting the salt deposited evenly on the polypropylene filter fibers, since the synthetic fibers are naturally hydrophobic, but a wetting process takes care of that.
The salt coating on the fibers is very fine, doesn’t affect breathability of the mask, and has been shown to be effective even in harsh environments. The research paper states that “salt coatings retained the pathogen inactivation capability at harsh environmental conditions (37 °C and a relative humidity of 70%, 80% and 90%).”
It’s a luxury to be able to access a modern machine shop, complete with its array of lathes, mills, and presses. These tools are expensive though, and take up a lot of space, so if you want to be able to machine hard or thick metals without an incredible amount of overhead you’ll need a different solution. Luckily you can bypass the machines in some situations and use electricity to do the machining directly.
This project makes use of a process known as electrochemical machining and works on the principle that electricity passed through an electrolyte solution will erode the metal that it comes in contact with. With a well-designed setup, this can be used to precisely machine metal in various ways. For [bob]’s use this was pretty straightforward, since he needed to enlarge an existing hole in a piece of plate steel, so he forced electrolyte through this hole while applying around half an amp of current in order to make this precise “cut” in the metal, avoiding the use of an expensive drill press.
There are some downsides to the use of this process as [bob] notes in his build, namely that any piece of the working material that comes in contact with the electrolyte will be eroded to some extent. This can be mitigated with good design but can easily become impractical. It’s still a good way to avoid the expense of some expensive machining equipment, though, and similar processes can be used for other types of machine work as well.
The shape of proteins largely controls their function, and if we can predict their shape then we get much closer to predicting how they interact. While AlphaFold 2 just predicts the static state, the sheer number of interactions that can change a protein, dynamic protein structures are still out of reach. The technical achievement of DeepMind is not to be understated. For a typical protein, there are an estimated 10^300 different configurations.
Out of the 180 million protein sequences in the Protein database, only 170,000 have had their structures identified. Technologies like the cryo-electron microscope make the process of mapping their structure easier, but it is still complex and tedious to go from sequence to structure. AlphaFold 2 and other folding algorithms are tested against this 170,000 member corpus to determine their accuracy. The previous highest-scoring algorithm of 2016 had a median global distance test (GDT) of 40 (0-100, with 100 being the best) in the most difficult category (free-modeling). In 2018, AlphaFold made waves by pushing that up to the high 50’s. AlphaFold 2 brings that GDT up to 87.
At this point in time, it is hard to determine what sort of effects this will have on the drug industry, healthcare, and society in general. Research has always been done to create the protein, identify what it does, then figure out its structure. AlphaFold 2 represents an avenue towards doing that whole process completely backward. Whether the next goal is to map all the proteins encoded in the human genome or find new, more effective drug treatments, we’re quite excited to see what becomes of this landmark breakthrough.