Will Superconducting Transistors Help Quantum Computers?

September 30, 2026 by Maya Posch 11 Comments

Despite all the glamorous promises made about quantum computing, it’s hard to make the argument that today’s quantum computers hold a candle to the sheer practicality of classical computers, especially when qubits need to be cuddled at cryogenic temperatures inside a cryostat. This is worsened by the problem that regular semiconductor transistors do not really appreciate these same cryogenic temperatures, creating an awkward interfacing problem for the controlling electronics.

Now a new pitch here is to create superconducting transistors that will happily work at temperatures near absolute zero. In an article in IEEE Spectrum this start-up – called S-Transistors – and their concept are covered.

By being able to have the control circuits inside the same cryostat, one can forego the absolute mess of wiring that has to penetrate it, and with it one major failure point. Their proposed solution uses the same Josephson junctions (JJs) that are also used for qubits, using a high enough current to briefly make it non-superconducting, inducing a voltage pulse that can be detected.

In addition, JJ-based field effect transistors (JJFETs) are used, with this 2025 paper by [Yusheng Xiong] et al. detailing these structures. Here S–Transistors claims that they are now able to manufacture JJFETs at scale, which would be another major breakthrough that could bring quantum computing just a little bit closer.

They’d be competing with cryogenic CMOS (Cry-CMOS), which can use standard semiconductor production lines to create circuits that can withstand cryogenic temperatures, albeit not quite a the near-zero K level that these superconducting transistors and JJFETs would be capable of.

Apple Finally Made AirPods Repairable… Sort Of

September 30, 2026 by Maya Posch 13 Comments

It’s been true for a while now that Apple’s AirPods have been effectively disposable, with [iFixit] slapping each successive generation with an abysmal 0/10 repairability score. The moment that any of the built-in batteries faltered you could effectively toss the whole package out as e-waste.

Interestingly, with the fifth generation it would seem that a battery swap in the earbuds is now actually possible without whole-scale destruction, according to the [iFixit] teardown video.

Although it’s still a far cry from the demonstrated FairBuds battery replacement, this time around a bit of gentle heat allows for the glued-together earbud to cleanly separate, with inside a socketed coin cell. The catch here is that the polarity on these sockets differs between the left and right earbud, which was discovered after a quick swap.

Unfortunately this same easy-to-open change doesn’t carry over to the case for the earbuds, which still requires physical destruction of the plastic to get to its battery. Accordingly [iFixit] gives this generation of AirPods a generous 2/10. Although a step in the right direction, it seems clear that if repairability or even simply being able to replace the batteries is a concern, the AirPod’s probably aren’t for you.

Last year’s third generation AirPods made [iFixit] really angry, so this is borderline glowing praise. Of course, the issue with non-removable batteries remains a problem, especially when new EU regulations that should have fixed this get watered down.

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Assembling And Testing A DIY Jet Turbine

September 30, 2026 by Maya Posch 14 Comments

After many months of painstaking work, [AlfMart CNC Garage] over at YouTube has finally reached the stage where he can fully assemble his DIY jet turbine and commence testing. Even if deceptively simple devices, just the starting mechanism turned out to be a challenge. Due to the extreme conditions that these jet turbines operate under, tolerances are narrow, and many of the materials require careful selecting and testing.

Fortunately this is not true for the outer casing, which is cobbled together from a commercial gas cylinder and a children’s steel drinking bottle that so happened to have the right dimensions. From there the parts get increasingly more specialized, down to the carefully balanced rotor. Assuming everything was done right up till this point, the first start-up will mean a happily roaring turbine and not a deafening explosion followed by a cloud of shrapnel.

In the video the full assembly can be observed, along with detailed instructions should anyone want to follow along with their own DIY jet turbine. Naturally a lot of attention has to be paid to tolerances during the assembly process. Following the basic turbine assembly, the RPM sensor circuit and the electrical starter are added, with the latter allowing for the turbine to spin up prior to ignition.

The first basic starter tests revealed an issue with the starter motor and clutch mechanism, requiring some upgrades. Before the first ignition the whole turbine has to be dynamically balanced, for which first a new balancing rig will be designed and assembled. While this means that first ignition will still be a while off, it’s best to take projects like this slow and steady. We’re also looking forward to seeing this new dynamic balancing rig that’s claimed to be much more advanced than that used for balancing the rotor.

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Determining Diamond’s Properties Under Extreme Pressures

September 29, 2026 by Maya Posch 2 Comments

Although graphene gives diamond a solid run for its money when it comes to being the most useful assembly of carbon atoms, both have the distinct property of material scientists still trying to figure out all their properties and potential applications. This includes something like the melting curve of diamond and potential phases beyond this diamond lattice phase that occur when exposed to extreme pressures and temperatures. Such as those experienced on a planetary scale and during inertial confinement fusion (ICF).

In this research (paywalled) by researchers at the Lawrence Livermore National Laboratory (LLNL), it was investigated how close theoretical simulations were to physical reality by blasting diamond samples with a laser. This ablated the surface and sent a shockwave through the material that caused it to melt. Using X-ray diffraction data this entire process was followed, elucidating the exact melting temperature under such conditions.

This revealed that previous estimates based on earlier experiments had been off by many hundreds of degrees, giving a far better idea of how diamond responds to such extreme pressures and temperatures. Where such information is very relevant is in fields like planetary science where diamonds can occur naturally and being able to predict their presence can be essential.

The other application, and the primary reason why LLNL does this kind of research is for the sake of ICF at the national ignition facility (NIF), which is the best way to investigate the behavior of e.g. hydrogen isotopes under extreme conditions like those of nuclear weapons.

Unfortunately this research will have no impact on practical power generation using nuclear fusion, as the only viable path there involves forms of magnetic confinement fusion (MCF), but it’s still pretty rad to improve our understanding this carbon form.

Designing A Fully 3D-Printed Mechanical Calculator

September 29, 2026 by Maya Posch 10 Comments

Even if almost tragically impractical in a world where digital calculators are cheap as chips, mechanical calculators and their big mechanical computer brethren remain an absolute marvel of engineering. Using nothing but elements like simple gears their motion is used to calculate everything from a simple multiplication to the proper targeting instructions for an Iowa-class battleship’s guns.

This fascination, along with the mind-bendingly high prices for commercial digital calculators led [3D all Workshop] to spend 2 months on designing his own mechanical calculator. Fully FDM 3D-printed, of course.

In the video the design process and troubleshooting step are covered along with the workings of the mechanisms for both addition and multiplication. While this may seem simple, basically converting numbers of rotations into a final indicator position, aspects like carrying a digit and adding a multiplication feature to the mechanism require some proper engineering.

Of course, using FDM printing for tolerance-sensitive things like gears meant that a lot of time was spent redesigning aspects of the mechanism, going through about a hundred design iterations until it worked, with the help from a bit of lubrication.

Naturally this isn’t the first 3D-printed mechanical calculator, not to mention ones made from wood, but always it’s pretty cool to see one made from first fundamentals.

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Testing Coulomb’s Law And Similar Fundamentals Yourself Remains Tricky

September 29, 2026 by Maya Posch 11 Comments

How easy is it to build a simple demonstration at home that proves fundamental law of physics, such as Coulomb’s inverse square law, or Maxwell’s equations? This is one of those questions that always nagged at [Casual Physics Enjoyer] as they sought to find ways to develop a more intuitive understanding of these fundamentals with simple DIY-at-home experiments. Unfortunately this turned out to be rather tricky for Coulomb’s law.

Us H. sapiens – courtesy of a few bright individuals – have figured out many of the fundamentals that underlie this physical world over the past few thousands of years. Even if we still got some pretty massive fundamentals left today for equally bright-minded folk to bash their collective heads against, basics like Coulomb’s law or Maxwell’s equations ought to be a snap now for the average person to replicate since they were after all performed in an era before quantum mechanics, computers or even electrification.

To the dismay of the average physics student, experiments that demonstrate these fundamental laws of physics are still pretty hard to replicate without some solid time and monetary investment. This is demonstrated quite succinctly in the linked article, where the question of how to demonstrate the force between two charged particles, as in Coulomb’s law, and that it is an inverse square relationship is attempted.

Whereas the Wikipedia entry claims it to be a ‘simple experiment’ with just two identical spheres, in a DIY setting this is somewhat tricky, including the part where you have to charge up the spheres and measure the force. Using some aluminium foil and wires you can get the two ends to separate as you’d expect, but quantifying the force is a whole other matter.

Pitting A CFD-Optimized Toroidal Propeller Against A Conventional One

September 28, 2026 by Maya Posch 23 Comments

Although we often think that we got certain aspects of aerodynamics pretty much licked at this point, details like the optimal shape of a propeller remains hotly debated, both in- and outside of academia. This also includes wilder designs like toroidal propellers that even after more than a hundred years are still mostly just being evaluated. Recently [Neuronautics] took a shot at figuring out whether toroidal propellers even make sense.

In order to do this, first an efficiency baseline was established using a conventional and highly optimized propeller. After scanning it in to get its exact geometry and running it through a computational fluid dynamics (CFD) simulation, the software spat out a number of about 73%.

This left figuring out an optimized shape for the toroidal propeller to pit against it. While you can absolutely brute-force the seventeen shape parameters being considered here and test them in CFD, this would take insanely long. The hack here is to use multiple reference frame (MRF) to drastically speed up the selection process, though even then it still took two months. An example of using MRF with regular propellers is discussed in a 2019 paper by [Randi Franzke] et al. in Energies.

Although MRF saves a lot of simulation time, you still end up with a lot of data that has to be analyzed for interesting patterns. For this [Neuronautics] trained a artificial neural network to automate filtering the many options for the most optimal ones, until converging onto a single design.

This G1401 design was the lucky winner, though with only a simulated 62.9% efficiency. Subsequently the one aspect that had been left unchanged was also iterated through, in the form of many different airfoil shapes until the final design appeared.

This design was then 3D printed in resin, which showed the first hurdle with the selection process, in that the printed versions were too thin and flexible to be usable as propellers. Cue many hours of manual tweaking of the design to make it actually printable.

Although the final design didn’t exceed 62% efficiency in a final test, the comment section to the video rightfully points out that the comparison was between a commercially made propeller and a DIY resin-printed one, which adds a whole other batch of variables. That said, it’s unlikely that there’d have been an obvious improvement either way, otherwise we’d already have seen toroidal propellers pop up everywhere on drones and aircraft.

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