Using Ultrasound And Microbubbles To Make Tiny Devices

October 20, 2026 by Maya Posch 9 Comments

Although we generally do not look at bubbles in fluids as more than a curiosity – if not an outright annoyance – in certain contexts they can be very useful. If you can namely control their formation and position, you can use them in small systems to control actuators and dynamically affect acoustic systems. The main issues here are that controlling their formation, lifetime and controllability remain hard to solve. This is what [Zhiyuan Zhang] et al. sought to address, with a recent study published in Science Advances covering their approach using ultrasound-driven, electronically programmable microbubbles.

There’s also a Cornell press release article about their findings, which uses a new device that produces hydrogen bubbles along a grid of electrodes, before using ultrasound to steer them around. Using this chip-like device they claim to be able to control the 10-100 micron sized bubbles, with the ultrasound matching the resonant frequency of the target bubble. With each bubble size having its own resonant frequency, this allows for individual control by varying the induced oscillations.

Although in the demonstrated 2D setup this microbubble approach works well, it still requires a fairly bulky bench top setup around it which would need to be scaled down to be more practical. There is also the issue that the chamber geometry affects the movement of a bubble, which becomes especially important to further research when using complex (3D) chambers with this technology.

Lazarus And The Free Pascal Compiler Gain Dynamic Package Support

October 20, 2026 by Maya Posch 26 Comments

If you have developed in Pascal or Delphi in the past decades, you’re probably familiar with the Lazarus IDE that provides an interface to the Free Pascal Compiler (FPC), much like Delphi’s IDE. For users of Lazarus IDE there’s now an exciting new development, with the announcement that FPC and Lazarus now support dynamic packages.

The upshot of this is that you no longer need to rebuild the IDE if you want to add components, controls and Lazarus extensions. In addition you can use this same dynamic package feature in your own Pascal applications this way.

Naturally this is a great improvement, and it’s good to see more improvements to such a venerable programming language. Not only is it still being used today for just about anything, including web development, but there is a good case to be made for using Pascal today as it’s no longer the language it was half a decade ago.

We’d also be remiss to not mention the legacy of [Niklaus Wirth], who not only created Pascal, but was also instrumental in the development of Object Pascal together with Apple. This effort ultimately led to everything from Turbo Pascal to Delphi, FPC and so much more, making it a heartening sight to see this legacy being kept alive today.

NASA’s Lunar Grounding Challenge Is A Real Buzz

October 20, 2026 by Maya Posch 31 Comments

One could make a joke about how an astronaut walking on the lunar surface is rather akin to a cat walking on the carpet in the living room, but out in space the resulting triboelectric discharge can do a lot more damage than just some stinging fingers and a bemused looking cat.

The problem that NASA and other space agencies are dealing with is that the charge that builds up on a lunar-walking astronaut is very hard to equalize with something like a lunar lander. For this reason they have now set up the Lunar Grounding Challenge to consult the public whilst dangling $150,000 of rewards in front of anyone ready to pounce with a good idea.

Here on Earth we have many ways in which we can get rid of unwanted charge: dry winter weather, for instance, demonstrates effectively that humidity is a crucial factor here. With no real atmosphere on the Moon, each astronaut becomes a walking capacitor, which is worsened when said astronaut ventures outside of the sunlit areas and then returns to the slightly positively charged lander.

The challenge here is to equalize the astronaut and lander, with a design specification of a -100 kV or higher astronaut and about 100 V lander. A resulting current should not exceed 1 mA, ideally less than 0.2 mA to remain below human perception levels. If an arc exists it should not contact the suit or astronaut.

Of course, the most low-tech solution would be to use a resistor to limit the current, but at those voltage ranges it would take an awful long time to bleed off, in an environment that’s basically a perfect insulator. It definitely seems like a fun challenge to sink one’s fangs into.

Super Mario Galaxy Now Runs On The GBA

October 20, 2026 by Maya Posch 2 Comments

Joining the ranks of fresh backported Nintendo games is Super Mario Galaxy for the Nintendo Game Boy Advance (GBA), courtesy of [Tobias Friedly], AKA [Tobi]. In a recent video he announces the release of this game, along with the release of the source code of the engine and all the game’s code in a GitHub project.

Naturally none of the original Wii game’s assets are provided to appease Nintendo’s vicious lawyers, so you’re expected to bring your own super-legally acquired ISO image or equivalent to fill in these blanks when you build your ROM for the GBA.

This is a mostly complete port, even integrating the star pointer despite the GBA’s limited number of controls compared to the Wii. In some situations it’s opted to have star bits automatically collected to work around this limitation, which is probably a quality-of-life improvement that many SMG players will appreciate.

For the game’s logic a lot of code was borrowed from the recently decompiled version of the original game, which saved a lot of time even if the GBA’s hardware is no match for the Wii’s. From the gameplay in the video it definitely looks like a playable version of the game, with an acceptable frame rate that looks to be worth a try.

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Making Photovoltaic Solar Cells With A Microwave

October 19, 2026 by Maya Posch 3 Comments

Although solar panels may seem like a kind of magic, they’re really quite simple devices, in their silicon form featuring nothing but the p-type silicon wafer and an n-type layer doped with e.g. phosphorus. Because of this simplicity it’s quite possible to make your own solar cells at home using only a few basic, off-the-shelf ingredients and a kiln, which in this recent video by [Dr. Semiconductor] uses a microwave kiln and thus justifies the video’s title.

Even the silicon wafer that you start with can be easily purchased online, though you have to be careful that it’s a bare wafer, without existing etchings on it. On this you need to get a phosphorus-rich layer, which is done by creating a delicious mixture of 1 mL of tetraethyl orthosilicate (TEOS), 0.3 mL of 85 wt% phosphoric acid, 5 mL of ethanol and 0.25 mL of distilled water. After low heat boiling this for 30 minutes, it is spincoated onto the cut square of silicon wafer using a spinning platform, like a PC fan.

Next, you shove the coated silicon into the kiln and put it into the microwave to bake at a fairly low power level for half an hour. In the video it took less than 50% power of the microwave to not melt the silicon, so remember that those microwave kilns get pretty hot.

With the delightful smells of freshly baked silicon now teasing your nostrils, you can then take out the doped silicon to sand or etch off the thin layer of glass that’s formed around the new PV cell. On the clear spots you can now put a gallium-indium contact on the p-type Si side and a wad of indium on the newly doped Si-P side, which are now your contacts for the PV cell.

The full recipe along with many of the issues discussed in the video can also be found on the blog article, though the video conclusion notes that many improvements are still possible. The created PV cell in the video reaches an efficiency of about 5%, but this could be improved through changes like the use of a clean-room, adding an anti-reflection coating and improving the contact with the cell.

Continue reading “Making Photovoltaic Solar Cells With A Microwave” →

The New Phobos Martian Moon Rover That Weighs In At Only 15 Grams

October 18, 2026 by Maya Posch 27 Comments

Although for many decades the planet Mars has been prodded, poked, driven upon, flown over and especially orbited by various spacecraft, landers and rovers sent over by a certain humanoid species on Earth, the two moons that orbit Mars have featured significantly more in science-fiction and video games than in scientific literature. This is now about to change when the Martian Moons eXploration (MMX) mission launches on October 19th, which will include a sample return from Phobos.

So far these two moons of Mars – Phobos and Deimos – have only received a few cursory glances by passing spacecraft, leaving many fundamental questions surrounding their formation and composition very much open. With the MMX mission this should change dramatically, with this spacecraft intended to perform detailed measurements of both moons.

In addition a rover – called Idefix – will perform a landing on Phobos for observations of its surface. This will be quite a feat as despite this lander coming in at 25 kg, on Phobos’ surface it will weigh only 15 grams due to the low gravity, or even less than the diminutive dog companion of Obelix, with potential bouncing as we have seen with previous landing attempts on such small bodies.

After launch, the MMX mission will take a year to arrive at Mars, in August of 2027, with Idefix being released in early 2029 for its hopefully soft paws-down on the surface of Phobos where it can scurry about for a while until the main MMX spacecraft lands later for its sample retrieval and return part of the mission. If everything goes well, this would mean that a sample of Phobos should be landing in Australia in 2031.

Busting The Myth That Plastics Are Chemically Inert In Water

October 17, 2026 by Maya Posch 4 Comments

One of the often made claims about plastics is that they are chemically inert under most conditions, such as when exposed to water. This long-held belief has also challenged the notion that micro- and nanoplastics (MNPs) are dangerous to organisms such as us human animals. A hitherto unknown mechanism between common plastics as investigated by [Naixin Qian] et al. and published in Nature serves to generate highly reactive hydroxyl radicals when exposed to water.

Hydroxyl radicals (HO^•) are the neutral form of the hydroxide ion (OH^–). It’s a free radical that tends to be extremely short-lived due to its reactivity, much like the singular oxygen molecule that is freed at the plastic-water interface. The energy provided for this reactivity comes from the electrostatic effect, itself highly correlated with many plastics, with the six types of microplastics used in the experiment showing varying levels of free radicals, particularly for the more hydrophobic types.

This high reactivity of free radicals is a well-known problem in cellular biology, with evolution having developed many tools over the years to deal with capturing these radicals as well as repair the (DNA) damage that they can cause. The effect of these microplastics and their generated free radicals was thus studied as well.

Of note here is that the electrostatic effect itself already serves to draw charged biomolecules to it, before the impact of free radicals is considered. By using mouse red blood cells and exposing them to polystyrene (PS) microplastics fatal damage was observed to the red blood cells.

This indicates that there are at least three possible ways in which MNPs can be harmful to organisms. It also provides another clue to how this may affect the ageing of plastics, among other implications.

Currently there is still ongoing debate on whether MNPs are truly harmful and just how prevalent they may be in e.g. our bodies. Reliably detecting them in e.g. biological tissues remains a challenge, which this new study may also be helpful with, since one of our biggest blind spots is that we lack solid knowledge of how MNPs may behave inside an organism.