Caltech Scientists Make Producing Plastics From CO2 More Efficient

July 16, 2025 by Maya Posch 26 Comments

For decades there has been this tantalizing idea being pitched of pulling CO₂ out of the air and using the carbon molecules for something more useful, like making plastics. Although this is a fairly simple process, it is also remarkably inefficient. Recently Caltech researchers have managed to boost the efficiency somewhat with a new two-stage process involving electrocatalysis and thermocatalysis that gets a CO₂ utilization of 14%, albeit with pure CO₂ as input.

The experimental setup with the gas diffusion electrode (GDE) and the copolymerization steps. (Credit: Caltech)

The full paper as published in Angewandte Chemie International is sadly paywalled with no preprint available, but we can look at the Supplemental Information for some details. We can see for example the actual gas diffusion cell (GDE) starting on page 107 in which the copper and silver electrodes react with CO₂ in a potassium bicarbonate (KHCO₃) aqueous electrolyte, which produces carbon monoxide (CO) and ethylene (C₂H₄). These then react under influence of a palladium catalyst in the second step to form polyketones, which is already the typical way that these thermoplastics are created on an industrial scale.

The novelty here appears to be that the ethylene and CO are generated in the GDEs, which require only the input of CO₂ and the potassium bicarbonate, with the CO2 recirculated for about an hour to build up high enough concentrations of CO and C₂H₄. Even so, the researchers note a disappointing final quality of the produced polyketones.

Considering that a big commercial outfit like Novomer that attempted something similar just filed for Chapter 11 bankruptcy protection, it seems right to be skeptical about producing plastics on an industrial scale, before even considering using atmospheric CO₂ for this at less than 450 ppm.

View inside the vacuum vessel of Wendelstein 7-X in Greifswald, Germany. (Credit: Jan Hosan, MPI for Plasma Physics)

Wendelstein 7-X Sets New Record For The Nuclear Fusion Triple Product

July 15, 2025 by Maya Posch 36 Comments

Fusion product against duration, showing the Lawson criterion progress. (Credit: Dinklage et al., 2024, MPI for Plasma Physics)

In nuclear fusion, the triple product – also known as the Lawson criterion – defines the point at which a nuclear fusion reaction produces more power than is needed to sustain the fusion reaction. Recently the German Wendelstein 7-X stellarator managed to hit new records here during its most recent OP 2.3 experimental campaign, courtesy of a frozen hydrogen pellet injector developed by the US Department of Energy’s Oak Ridge National Laboratory. With this injector the stellarator was able to sustain plasma for over 43 seconds as microwaves heated the freshly injected pellets.

Although the W7-X team was informed later that the recently decommissioned UK-based JET tokamak had achieved a similar triple product during its last – so far unpublished – runs, it’s of note that the JET tokamak had triple the plasma volume. Having a larger plasma volume makes such an achievement significantly easier due to inherently less heat loss, which arguably makes the W7-X achievement more noteworthy.

The triple product is also just one of the many ways to measure progress in commercial nuclear fusion, with fusion reactors dealing with considerations like low- and high-confinement mode, plasma instabilities like ELMs and the Greenwald Density Limit, as we previously covered. Here stellarators also seem to have a leg up on tokamaks, with the proposed SQuID stellarator design conceivably leap-frogging the latter based on all the lessons learned from W7-X.

Top image: Inside the vacuum vessel of Wendelstein 7-X. (Credit: Jan Hosan, MPI for Plasma Physics)

Quasi-Quantifying Qubits For 100 Quid

July 14, 2025 by Adam Zeloof 3 Comments

As part of his multi-year project to build a quantum computer, hacakday.io poster [skywo1f] has shared with us his most recent accomplishment — a Nuclear Magnetic Resonance Spectrometer, which he built for less than $100.

The NMR spectrometer is designed to disturb protons, which naturally line up according to the Earth’s magnetic field, using an electric coil. Once disturbed, the protons nutate (a fancy physics word for wobble), and flip quantum spin states. [skywo1f]’s NMR device can detect these spin state changes, as he demonstrates with a series of control experiments designed to eliminate sources of false positives (which can be annoyingly prevalent in experimental physics). His newest experimental device includes a number of improvements over previous iterations, including proper shielding, quieter power topology, and better coil winding in the core of the device. Everything was assembled with cost in mind, while remaining sensitive enough to conduct experiments — the whole thing is even driven by a Raspberry Pi Pico.

Here at Hackaday, we love to see experiments that should be happening in million-dollar laboratories chugging along on kitchen tables, like this magnetohydrodynamic drive system or some good old-fashioned PCB etching. [skywo1f] doesn’t seem to be running any quantum calculations yet, but the NMR device is an important building block in one flavor of quantum computer, so we’re excited to see where he takes his work next.

Citizen Science Is All Fun And Games

July 13, 2025 by Al Williams 7 Comments

You are probably familiar with initiatives like Seti@Home, where you donate unused computer power to some science project that needs computer cycles. [Jeff Yoshimi] wants to borrow your most powerful computer: your brain. The reason: cancer research.

[Jeff’s] recent book, Gaming Cancer, has three examples: Eterna, Foldit, and Nanocrafter. All three make games out of creating biological molecules. With Foldit, you create proteins in a bonsai-like fashion. EteRNA is more like Sudoku for RNA. Nanocrafter used DNA strands as puzzle pieces, although it is no longer operational. Their website, amusingly, looks like it was taken over by a slot machine site and a probably AI-generated text tries to convince you that slot machines are much like fusing DNA strands.

What can these projects do? Eterna’s open vaccine challenge used gameplay to help design RNA molecules for vaccines that don’t require ultra-cold storage, and the results drove improvements in real-life vaccines.

There have been several science fiction stories that center on the idea that a game of some sort might be an entrance test to a super-secret organization (The Last Starfighter or Stargate: Universe, for example). Maybe a future science game will trigger scholarship or job offers. It could happen.

We like citizen science. Zooniverse does a good job of making it fun, but maybe not to the level of a game. You can make contributions in space, or even right here on Earth.

DIY X-Rays Made Easy

July 11, 2025 by Al Williams 32 Comments

Who doesn’t want an X-ray machine? But you need a special tube and super high voltage, right? [Project 326] says no, and produces a USB-powered device that uses a tube you can pick up two for a dollar. You might guess the machine doesn’t generate X-rays with a lot of energy, and you’d be right. But you can make up for it with long exposure times. Check out the video below, with host [Posh Arthur].

The video admits there are limitations, of course. We were somewhat sad that [Project 326] elected not to share the exact parts list and 3D printed files because in the unlikely event someone managed to hurt themselves with it, there could be a hysterical reaction. We agreed, though, that if you are smart enough to handle this, you’ll be smart enough to figure out how to duplicate it — it doesn’t look that hard, and there are plenty of not-so-subtle clues in the video.

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No Tension For Tensors?

July 9, 2025 by Al Williams 11 Comments

We always enjoy [FloatHeadPhysics] explaining any math or physics topic. We don’t know if he’s acting or not, but he seems genuinely excited about every topic he covers, and it is infectious. He also has entertaining imaginary conversations with people like Feynman and Einstein. His recent video on tensors begins by showing the vector form of Ohm’s law, making it even more interesting. Check out the video below.

If you ever thought you could use fewer numbers for many tensor calculations, [FloatHeadPhysics] had the same idea. Luckily, imaginary Feynman explains why this isn’t right, and the answer shows the basic nature of why people use tensors.

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Dithering With Quantization To Smooth Things Over

July 9, 2025 by Maya Posch 19 Comments

It should probably come as no surprise to anyone that the images which we look at every day – whether printed or on a display – are simply illusions. That cat picture isn’t actually a cat, but rather a collection of dots that when looked at from far enough away tricks our brain into thinking that we are indeed looking at a two-dimensional cat and happily fills in the blanks. These dots can use the full CMYK color model for prints, RGB(A) for digital images or a limited color space including greyscale.

Perhaps more interesting is the use of dithering to further trick the mind into seeing things that aren’t truly there by adding noise. Simply put, dithering is the process of adding noise to reduce quantization error, which in images shows up as artefacts like color banding. Within the field of digital audio dithering is also used, for similar reasons. Part of the process of going from an analog signal to a digital one involves throwing away data that falls outside the sampling rate and quantization depth.

By adding dithering noise these quantization errors are smoothed out, with the final effect depending on the dithering algorithm used.

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