News comes to us this week that the famous HAARP antenna array is to be brought back into service for experiments by the University of Alaska. Built in the 1990s for the US Air Force’s High Frequency Active Auroral Research Program, the array is a 40-acre site containing a phased array of 180 HF antennas and their associated high power transmitters. Its purpose it to conduct research on charged particles in the upper atmosphere, but that hasn’t stopped an array of bizarre conspiracy theories being built around its existence.
The Air Force gave up the site to the university a few years ago, and it is their work that is about to recommence. They will be looking at the effects of charged particles on satellite-to-ground communications, as well as over-the-horizon communications and visible observations of the resulting airglow. If you live in Alaska you may be able to see the experiments in your skies, but residents elsewhere should be able to follow them with an HF radio. It’s even reported that they are seeking reports from SWLs (Short Wave Listeners). Frequencies and times will be announced on the @UAFGI Twitter account. Perhaps canny radio amateurs will join in the fun, after all it’s not often that the exact time and place of an aurora is known in advance.
Tinfoil hat wearers will no doubt have many entertaining things to say about this event, but for the rest of us it’s an opportunity for a grandstand seat on some cutting-edge atmospheric research. We’ve reported in the past on another piece of upper atmosphere research, a plan to seed it with plasma from cubesats, and for those of you that follow our Retrotechtacular series we’ve also featured a vintage look at over-the-horizon radar.
HAARP antenna array picture: Michael Kleiman, US Air Force [Public domain], via Wikimedia Commons.
We’ve learned a lot by watching the talks from the Hackaday Superconferences. Still, it’s a rare occurrence to learn something totally new. Microwave engineer, professor, and mad hacker [Toshiro Kodera] gave a talk on some current research that he’s doing: replacing natural magnetic gyrotropic material with engineered metamaterials in order to make two-way beam steering antennas and more.
If you already fully understood that last sentence, you may not learn as much from [Toshiro]’s talk as we did. If you’re at all interested in strange radio-frequency phenomena, neat material properties, or are just curious, don your physics wizard’s hat and watch his presentation. Just below the video, we’ll attempt to give you the Cliff’s Notes.
Projection mapping is pretty magical; done well, it’s absolutely miraculous when the facade of a building starts popping out abstract geometric objects, or crumbles in front of our very eyes. “Dynamic projection mapping onto deforming non-rigid surface” takes it to the next level. (Watch the video below.)
A group in the Ishikawa Watanabe lab at the University of Tokyo has a technique where they cover the target with a number of dots in an ink that is only visible in the infra-red. A high-speed (1000 FPS!) camera and some very fast image processing then work out not only how the surface is deforming, but which surface it is. This enables them to swap out pieces of paper and get the projections onto them in real time.
Researchers at MIT have used 3D printing to open the door to low-cost, scalable, and consistent generation of microencapsulated particles, at a fraction of the time and cost usually required. Microencapsulation is the process of encasing particles of one material (a core) within another material (a shell) and has applications in pharmaceuticals, self-healing materials, and dye-based solar cells, among others. But the main problem with the process was that it was that it was slow and didn’t scale, and it was therefore expensive and limited to high-value applications only. With some smart design and stereolithography (SLA) 3D printing, that changed. The researchers are not 3D printing these just because they can; they are printing the arrays because it’s the only way they can be made.
A group at the Hasso-Plattner Institute in Germany explored a curious idea: using 3D printed material not just as a material – but as a machine in itself. What does this mean? The clearest example is the one-piece door handle and latch, 3D printed on an Ultimaker 2 with pink Ninjaflex. It is fully functional but has no moving parts (besides itself) and has no assemblies. In other words, the material itself is also the mechanism.
The video (embedded below) showcases some similar concept pieces: door hinges, a pair of pliers, a pair of walker legs, and a pantograph round out the bunch. Clearly the objects aren’t designed with durability or practicality in mind – the “pliers” in particular seem a little absurd – but they do demonstrate different takes on the idea of using a one-piece item’s material properties as a functional machine in itself.
We sometimes look back fondly on the old days where you could–it seems–pretty easily invent or discover something new. It probably didn’t seem so easy then, but there was a time when working out how to make a voltage divider or a capacitor was a big deal. Today–with a few notable exceptions–big discoveries require big science and big equipment and, of course, big budgets. This probably isn’t unique to our field, either. After all, [Clyde Tombaugh] discovered Pluto with a 13-inch telescope. But that was in 1930. Today, it would be fairly hard to find something new with a telescope of that size.
However, there are ways you can contribute to large-scale research. It is old news that projects let you share your computers with SETI and protein folding experiments. But that isn’t as satisfying as doing something personally. That’s where Zooniverse comes in. They host a variety of scientific projects that collect lots of data and they need the best computers in the world to crunch the data. In case you haven’t noticed, the best computers in the world are still human brains (at least, for the moment).
Their latest project is Radio Meteor Zoo. The data source for this project is BRAMS (Belgian Radio Meteor Stations). The network produces a huge amount of readings every day showing meteor echoes. Detecting shapes and trends in the data is a difficult task for computers, especially during peak activity such as during meteor showers. However, it is easy enough for humans.
There’s nothing wrong with the rough experiments like hanging a 1 L bottle of water from the end of a rectangular test print to compare strengths. We also have our rules-of-thumb, like expecting the print to perform at 30% of injection molded strength. But these experiments are primitive and the guidelines are based on hearsay. Like early metallurgy or engineering; 3D printing is full of made-up stuff.
What [Sam] has done here is really amazing. He’s produced a model of a printed ABS part and experimentally verified it to behave close enough to the real thing. He’s also set a method for testing and proposed a new set of questions. If it couldn’t be better, he also included his full research notebook. Make sure to read the FDMProperties-report (PDF) in the files section of Hackaday.io.
If research like this is being done elsewhere, it’s either internal to a large 3D printer manufacturer, or it’s behind a paywall so thorough only the Russians can help a regular peasant get through to them. Anyone with access to a materials testing lab can continue the work (looking at you every single engineering student who reads this site) and begin to help everyone achieve an understanding of 3D printed parts that could lead to some really cool stuff one day.