Although the term ‘quantum battery’ is a bit of a vague term, the cell that [Kieran Hymas] et al. demonstrate in a recent paper does seem to suggest that it uses quantum effects to charge faster than would otherwise be possible, with this rate increasing faster than its volume, meaning at a superextensive rate.

The general idea behind a quantum battery is that these somehow use a quantum effect to store and release energy faster than would be possible using classical physics. First proposed in 2013, the initial Dicke model saw its theoretical quantum advantage shot down by 2020, leading to the search for alternative models.

We have previously seen claims of a quantum advantage in batteries based on the Sachdev-Ye-Kitaev model, such as by [Davide Rossini] et al., but this new paper may be the first prototype cell demonstrating a reproducible effect.

In the here demonstrated cell a microcavity is created with strong light-matter coupling, allowing for both energy storage and discharging, with the illuminated particles super-absorbing the light with what the researchers claim to be due to these particles cooperating using a quantum mechanism. Effectively scaling up the cell would thus scale up the charge- and discharge rate faster than in a conventional chemical cell.

Whether this demonstration can be replicated and expanded upon remains to be seen, naturally. The stored energy in this experiment was very small and the storage time only very brief, so for now it serves primarily as an interesting experimental result for researchers to dig through.

Airborne micro particles can be a significant health hazard in a workshop, and thus it’s important to maintain a high standard of ventilation. But monitoring their concentration is also important, and thus there exists a range of sensors to help keep you safe. [WeSpeakEnglish] has taken this idea to the MAX, with a PM2.5 sensor that drives a very large wall mounted display. You’ll never be uncertain what the level is now!

The standout feature of this thing is a huge addressable LED seven segment display PCB, upon the back of which sits a tiny Seeed Studio Xiao board to which the particle sensor is hooked up. The software displays the particle count, and handily changes the colour as the number creeps upwards. Meanwhile should you wish to log the readings, the USB exposes a serial port upon which they are placed.

We can see this is a useful project for anywhere that is likely to have a high particle count, but it’s worth noting also that a large 7-segment display with an ESP32 board attached could have plenty of other uses. Meanwhile this is a nicely finished air quality monitor, but it’s certainly not the first we’ve seen.

In the world of silicon semiconductors, the process of creating transistors and similar structures involves various rounds of modifications and additions in order to create the requisite functional layers. A less involved approach would simply create these structures in-situ, with research the past years having focused on transition-metal dichalcogenide (TMDC) monolayers to do exactly this. Recently [Seok Young Min] et al. reported (paywalled, Phys.org summary) on creating transistors in-situ in a tungsten ditelluride (WTe₂) monolayer.

By selectively changing parts of the top layer into tungsten oxide (WO_x) as an insulator and other sections into n-type WS₂ and p-type WSe₂ the researchers were able to create functional MOSFETs, without the normally requisite grafting on of different materials. An obvious advantage of this is that this can be done at an atomic scale, potentially achieving densities significantly higher than with industry standard silicon semiconductor technology.

WTe₂ is not the only TMDC that could be viable here, of course, with other researchers investigating the use of MoSe₂ for a similar purpose, as in this research by [N. Lu] et al. from 2014. This being the creation of 2D semiconductors, referring to the thin layers of these monolayer TMDCs, along with potentially other materials such as graphene.

One of the major limits of mass-produced batteries is the electrolyte. From lead-acid to lithium ion, there’s some temperature where the electrolyte will freeze and cause all sorts of problems, from cracked casings to various non-favorable chemical changes in the battery itself. But if there’ a solid electrolyte available, many of the downsides of charging and discharging batteries in extreme cold disappear. These batteries developed by NASA, for example, can survive some wild temperature swings.

The electrolytes used for these batteries are either a ceramic or polymer electrolyte, both of which are solid. In testing, the batteries could meaningfully operate at temperatures of -60° C and up to 80° C on the high end. Further, the solid electrolyte helps protect them even outside of these temperature ranges. Bringing the battery temperature down to -170° C was not enough to damage the battery at all, and using a small heater to bring the temperature back up to its operating range showed no capacity losses or other issues.

These batteries are eventually intended for use in some of the coldest places outside of Earth still accessible to humans (in theory) such as the south pole of the Moon where the temperatures regularly get that cold and stay cold for long periods, especially in permanently-shadowed craters or places on the Moon we might want to put some telescopes eventually. There are other terrestrial situations where these batteries might be useful as well, since they don’t need as much thermal management as other battery types.

Before the advent of effective semiconductor LEDs many display types existed to display things like numbers and other characters. The Nixie tube is a well-known one, along with VFDs and there are also lesser known ones such as Burrough’s Panaplex, which all saw plentiful use in everything from calculators to audio equipment. The design that [Witchcraft and Alchemy] made appears to lean heavily on this Panaplex design.

Rather than neon, this uses argon as the gas. The anode is formed by the indium-tin oxide layer on a piece of glass, with the cathode sputtered onto the other side in the form of first a titanium layer followed by platinum. This combination helps to prevent the latter from flaking off due to incompatibilities between the molecular matrices of the glass and platinum.

Since this is an early prototype, only five segments were sputtered onto the glass and driven with a 74141 Nixie driver IC, creating the expected purple glow in a vacuum chamber. Following this a self-contained prototype was created, but this proved to be less successful, with the prototype quickly failing to light up as expected.

For a next attempt no tape or epoxy for sealing the device will be used, but rather a gasket instead of gluing the front glass onto the device. The use of conductive vias should make the device’s vacuum more permanent, and enable those last two segments to make it a seven-segment display. The final change should be to use a Penning mixture instead of pure argon.

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.

Coral bleaching is a major problem for ocean ecosystems as the ocean gets warmer. Researchers at Stanford have found a new method for regenerating bleached corals.

Scientists working on coral found that when they had a bleached and healthy example accidentally touching in the lab, the symbionts from the healthy coral that make its food were able to spread to the bleached coral, reviving it in a matter of weeks. Contact was only required for one week, although three days was sufficient in a few cases. The effect only seems to work with corals of the same genet as the healthy corals of other genets just take over the bleached coral antagonistically.

This is particularly exciting, as areas where not all coral has bleached may indicate the presence of symbionts that are more heat tolerant, and being able to spread these symbionts to their neighbors quickly can greatly speed up the process of coral regeneration and save the reef. Coral reefs are some of the most vibrant ecosystems in the ocean, so if you save the coral, you can save many other species as well that rely on them.

If you’d like to explore how the coral is doing near you, perhaps you should try an open ROV or a bionic jellyfish?

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.

We know [The Action Lab] always has something hands-on. This time, the video shows a toroidal plasma demo and how it relates to nuclear fusion. Plasma has a high temperature, and if you use physical electrodes to excite the plasma, this high temperature tends to destroy the electrodes. But thanks to the relationship between electricity and magnetism, you can create plasma with an alternating magnetic field instead of physical electrodes.

The actual practical device is a 10 MHz source with a coil and a low-pressure globe full of xenon gas. It looks pretty cool. Of course, the little tabletop demo isn’t strong enough to drive a fusion reaction. But if you scale it up and make some modifications, including using hydrogen, you get a tokamak reactor.

The problem, of course, is that current reactors need more energy to operate than they produce. But we keep hearing that nuclear fusion is right around the corner. One day, that’ll probably be true.

Of course, you can build your own fusion device. Just don’t expect to generate net power.

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.

Determining the shape of an object which can change dynamically is a bit of a challenge, one that especially vexes those who are really into Virtual Reality. Sensing the orientation of various limbs and appendages usually requires external sensors like cameras, or limit the focus to specific details like just the hands and fingers of the player. A more comprehensive and potentially flexible approach might be possible using optical waveguides, as demonstrated by [Qifan Yu] et al. in a recent article in Advanced Intelligent Systems.

Waveguides are structures that guide electromagnetic waves, with optical waveguides such as used here targeting EM radiation in the optical band. This can even allow for the use of cheap and plentiful optical fiber, though here custom elastomeric waveguides are manufactured. These are laid out onto the sheet in a double-sided, overlapping zig-zag pattern, which allows for easy reconstruction of the shape of said sheet based on how the wave propagation through the waveguide changes.

By characterizing the behavior of the signals through the waveguide, its shape and thus that of the sheet can be reconstructed. This was then demonstrated to be accurate by wrapping the sheet around a volunteer’s arm, elbow and hand, detecting the flexing and movement of individual joints.

Although fairly bulky in the demonstrated configuration and with an unoptimized algorithm, it’s conceivably something that can be miniaturized to the point where it can be woven into regular fabric. This could make for sensor sheets that could track the configuration of everything from robots to human bodies for something like VR purposes.

The variant of origami called kirigami (‘cut paper’ in Japanese) also starts off with a sheet of paper, but it allows for cutting the paper to increase the number of shapes that you can create. It is this technique that [Matthew Lim] used to create a number of three-dimensional designs that can convert between a flat configuration and some kind of functional object without any bolts, glue or similar. These include everything from a phone grip to a pretty sizeable side table.

The video starts with an interesting demonstration of how to fold an origami crane that has a smaller crane on its back. This is documented in a 1797 book on the many ways to fold a crane, with one of the first known instances where cuts are made in the single sheet of paper, which becomes the second, much smaller crane.

The same book extends that idea into making an origami grid that can fold into a grid of cranes after making a series of cuts. Later this form of origami got the name ‘kirigami’, with the video demonstrating how a few strategic cuts in an original flat shape can make it much more functional, based on scientific papers like this 2024 one by [Liu] et al. on cylindrical origami with tunable mechanical behavior.

For these functional mechanisms a laser cutter and FDM printer are used to prototype and test increasingly more advanced versions of the pop-up mechanism, before moving on to make full-sized furniture using plywood panels and 3D printed hinges. The coolest part about the resulting table is that it can be changed into different configurations, with the mechanism locking into its new position to make a relatively stable new shape.

Even if not immediately practical, these mechanisms provide interesting options for robotics and flat-pack furniture alike, as well as in applications like space exploration where every gram and cubic millimeter of space counts.

Atomic clocks are super accurate. But, unsurprisingly, some atomic clocks are better than others, depending on your definition of better. Researchers at Vienna University claim to have a superior thorium-based atomic clock. It isn’t necessarily more accurate than other atomic clocks, but it is self-regulating.

Apparently, prior atomic clocks need help to stay stable. But scientists have thought that thorium, with its very narrow gap between two states, would make an excellent clock with the help of a laser. However, the laser has to have precise properties that, at least in early experiments, were provided by another nuclear clock.

Obviously, you’d like to be able to use a laser to excite the source — a thorium crystal in this case — and then use the output of that to adjust the laser. That’s apparently what the team has done. If the laser drifts, the thorium nuclei absorb less light, and that adjusts the output frequency to compensate. If you can follow the physics, you can read the source paper in Nature.

Optical atomic clocks are the way to go for time standards, but this research has promise to provide even more accurate results in the future.

The Abric Romaní site in Spain is rather unique in archeology for one simple reason: the caves in its limestone-rich cliff have seen humanoid occupation for thousands of years. A thick layer of calcium carbonate-based travertine deposit has, over time, covered and largely preserved tools and other implements, including those made of wood. Over many decades of archeological exploration, 597 wooden imprints have been uncovered, with a recent research article by [Palmira Saladié] et al. detailing these findings.

Wood is one of those archaeological artefacts that are very elusive due to their fragility, even though we know that wood has been used pretty much everywhere from the first day that a humanoid critter discovered that branches make great clubs and spears, and can also easily be shaped to make them even more useful.

The wooden imprints and some larger remains of wooden implements were found, ranging from wooden spears and clubs to trays (see heading image) and tripods. With enough of the wood still present, researchers were also able to determine which types of trees were used to make these tools, and sometimes which part of the tree.

These finds date back to between 62,000 and 40,000 years ago during the Middle Paleolithic era. This would have been around the time that Homo sapiens began to move into Europe, with both species of humans living side by side for thousands of years. These days, the only active traces of this can be found in our DNA, which retains bits of H. neanderthalensis.

The supplemental materials PDF  breaks down some of this site’s more recent history. The sole reason that this crucial archaeological site was discovered was that the landowner in the early 20th century expressed a profound interest in archaeology and other natural sciences.

Thanks to this lucky find, we gained some insight into how our ancestors would have learned how to create crude wooden implements, before eventually moving on to smelting metals and eventually sand in order to make it into computer chips.

Most home security sensors require a chemical battery or external power source to operate, which can be a point of weakness. If the battery in a window or door sensor dies overnight and nobody is there to swap it, it might miss that one intruder or mess up your carefully curated home automation system. In that sense self-powered sensors are rather interesting, such as this one by [Manas Tiwari] and [Deepak Bharti] that is based around the triboelectric effect.

The research article is sadly paywalled, but the IEEE Spectrum article covers all the salient details. The sensor uses ground up garlic peel for the positive side of this triboelectric nanogenerator (TENG) as they call it, with a sheet of polyethylene (PE) forming the negative side. Once installed on a door frame, opening said door generates about 210 VAC with a 45 µA short circuit current. A dual-side layer of garlic peel bumps this up to 400 VAC and 65 µA.

As installed, the researchers used this generated current to detect changes using a separate MCU running off a powerbank, which obviously does not really solve the ‘running out of charge’ issue. The generated power could conceivably be used to send a brief wireless packet to a receiver elsewhere in the room, somewhat like the Bluetooth link in the example, but more low-power.

The researchers also reported that this sensor was still functional after half a year in storage, and survived 200 stress cycles, which seems like a good start for what appears to be a very cheap sensor to construct.