A balding man in a blue suit and tie sits behind rows of plants on tables. A bright yellow watering can is close to the camera and out of focus.

Phytoremediation To Clean The Environment And Mine Critical Materials

February 28, 2025 by Navarre Bartz 10 Comments

Nickel contamination can render soils infertile at levels that are currently impractical to treat. Researchers at UMass Amherst are looking at how plants can help these soils and source nickel for the growing EV market.

Phytoremediation is the use of plants that preferentially hyperaccumulate certain contaminants to clean the soil. When those contaminants are also critical materials, you get phytomining. Starting with Camelina sativa, the researchers are looking to enhance its preference for nickel accumulation with genes from the even more adept hyperaccumulator Odontarrhena to have a quick-growing plant that can be a nickel feedstock as well as produce seeds containing oil for biofuels.

Despite being able to be up to 3% Ni by weight, Odontarrhena was ruled out as a candidate itself due to its slow-growing nature and that it is invasive to the United States. The researchers are also looking into what soil amendments can best help this super Camelina sativa best achieve its goals. It’s no panacea for expected nickel demand, but they do project that phytomining could provide 20-30% of our nickel needs for 50 years, at which point the land could be turned back over to other uses.

Recycling things already in technical cycles will be important to a circular economy, but being able to remove contaminants from the environment’s biological cycles and place them into a safer technical cycle instead of just burying them will be a big benefit as well. If you want learn about a more notorious heavy metal, checkout our piece on the blessings and destruction wrought by lead.

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Building An Interferometer With LEGO

February 28, 2025 by Lewin Day 14 Comments

LEGO! It’s a fun toy that is popular around the world. What you may not realize is that it’s also made to incredibly high standards. As it turns out, the humble building blocks are good enough to build a interferometer if you’re so inclined to want one. [Kyra Cole] shows us how it’s done.

The build in question is a Michelson interferometer; [Kyra] was inspired to build it based on earlier work by the myphotonics project. She was able to assemble holders for mirrors and a laser, as well as a mount for a beamsplitter, and then put it all together on a LEGO baseboard. While some non-LEGO rubber bands were used in some areas, ultimately, adjustment was performed with LEGO Technic gears.

Not only was the LEGO interferometer able to generate a proper interference pattern, [Kyra] then went one step further. A Raspberry Pi was rigged up with a camera and some code to analyze the interference patterns automatically. [Kyra] notes that using genuine bricks was key to her success. Their high level of dimensional accuracy made it much easier to achieve her end goal. Sloppily-built knock-off bricks may have made the build much more frustrating to complete.

We don’t feature a ton of interferometer hacks around these parts. However, if you’re a big physics head, you might enjoy our 2021 article on the LIGO observatory. If you’re cooking up your own physics experiments at home, don’t hesitate to drop us a line!

Thanks to [Peter Quinn] for the tip!

A blue-gloved hand holds a glass plate with a small off-white rectangular prism approximately one quarter the area of a fingernail in cross-section.

AI Helps Researchers Discover New Structural Materials

February 27, 2025 by Navarre Bartz 18 Comments

Nanostructured metamaterials have shown a lot of promise in what they can do in the lab, but often have fatal stress concentration factors that limit their applications. Researchers have now found a strong, lightweight nanostructured carbon. [via BGR]

Using a multi-objective Bayesian optimization (MBO) algorithm trained on finite element analysis (FEA) datasets to identify the best candidate nanostructures, the researchers then brought the theoretical material to life with 2 photon polymerization (2PP) photolithography. The resulting “carbon nanolattices achieve the compressive strength of carbon steels (180–360 MPa) with the density of Styrofoam (125–215 kg m⁻³) which exceeds the specific strengths of equivalent low-density materials by over an order of magnitude.”

While you probably shouldn’t start getting investors for your space elevator startup just yet, lighter materials like this are promising for a lot of applications, most notably more conventional aviation where fuel (or energy) prices are a big constraint on operations. As with any lab results, more work is needed until we see this in the real world, but it is nice to know that superalloys and composites aren’t the end of the road for strong and lightweight materials.

We’ve seen AI help identify battery materials already and this seems to be one avenue where generative AI isn’t just about making embarrassing photos or making us less intelligent.

Building A DIY Muon Tomography Device For About $100

February 26, 2025 by Maya Posch 24 Comments

Muon tomography, or muography, is the practice of using muons generated by cosmic rays interacting with Earth’s atmosphere to image structures on Earth’s surface, akin to producing an X-ray. In lieu of spending a fair bit of money on dedicated muon detectors, you can also hack such a device together with two Geiger-Müller tubes and related circuitry for about $100 or whatever you can source the components for.

The reason for having two Geiger-Müller tubes is to filter out other much more prevalent sources of ionizing radiation that we’re practically bathed in every second. Helped by a sheet of lead between both tubes, only a signal occurring at the same time from both tubes should be a muon. Specially cosmic ray muons, as these have significantly more kinetic energy that allows them to pass through both tubes. As a simple check it’s helpful to know that most of these muons will come from the direction of the sky.

The author of the article tested this cobbled-together detector in an old gold mine. Once there the presence of more rock, and fewer muons, was easily detected, as well as a surge in muons indicating a nearby void from a mine shaft. While not a fast or super-easy way to image structures, it’s hard to beat for the price and the hours of fun you can have while spelunking.

Too Smooth: Football And The “KnuckleBall” Problem

February 26, 2025 by Lewin Day 25 Comments

Picture a football (soccer ball) in your head and you probably see the cartoon ideal—a roughly spherical shape made with polygonal patches that are sewn together, usually in a familiar pattern of black and white. A great many balls were made along these lines for a great many decades.

Eventually, though, technology moved on. Footballs got rounder, smoother, and more colorful. This was seen as a good thing, with each new international competition bringing shiny new designs with ever-greater performance. That was, until things went too far, and the new balls changed the game. Thus was borne the “knuckleball” phenomenon.

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New Camera Does Realtime Holographic Capture, No Coherent Light Required

February 26, 2025 by Donald Papp 31 Comments

Holography is about capturing 3D data from a scene, and being able to reconstruct that scene — preferably in high fidelity. Holography is not a new idea, but engaging in it is not exactly a point-and-shoot affair. One needs coherent light for a start, and it generally only gets touchier from there. But now researchers describe a new kind of holographic camera that can capture a scene better and faster than ever. How much better? The camera goes from scene capture to reconstructed output in under 30 milliseconds, and does it using plain old incoherent light.

The camera and liquid lens is tiny. Together with the computation back end, they can make a holographic capture of a scene in under 30 milliseconds.

The new camera is a two-part affair: acquisition, and calculation. Acquisition consists of a camera with a custom electrically-driven liquid lens design that captures a focal stack of a scene within 15 ms. The back end is a deep learning neural network system (FS-Net) which accepts the camera data and computes a high-fidelity RGB hologram of the scene in about 13 ms. How good are the results? They beat other methods, and reconstruction of the scene using the data looks really, really good.

One might wonder what makes this different from, say, a 3D scene captured by a stereoscopic camera, or with an RGB depth camera (like the now-discontinued Intel RealSense). Those methods capture 2D imagery from a single perspective, combined with depth data to give an understanding of a scene’s physical layout.

Holography by contrast captures a scene’s wavefront information, which is to say it captures not just where light is coming from, but how it bends and interferes. This information can be used to optically reconstruct a scene in a way data from other sources cannot; for example allowing one to shift perspective and focus.

Being able to capture holographic data in such a way significantly lowers the bar for development and experimentation in holography — something that’s traditionally been tricky to pull off for the home gamer.

Harvesting Water With High Voltage

February 24, 2025 by Maya Posch 50 Comments

Atmospheric water harvesting is a way to obtain fresh water in arid regions, as there is always some moisture in the air, especially in the form of morning fog. The trick lies in capturing this moisture as efficiently as possible, with a range of methods available that start at ancient low-tech methods involving passive fog droplet capture all the way to variants of what are effectively large dehumidifiers.

A less common way involves high-voltage and found itself the subject of a recent Plasma Channel video on YouTube. The inspiration for the build was a 2018 paper by [Maher Damak] et al. (PDF) titled Electrostatically driven fog collection using space charge injection.

One of the two stakes that make up the electrostatic precipitator system for atmospheric water harvesting. (Credit: Plasma Channel, YouTube)

Rather than passively waiting for dew to collect on the collector, as with many of the methods detailed in this review article by [Xiaoyi Liu] et al., this electrostatic approach pretty much does what it says on the tin. It follows the principle of electrostatic precipitators with a high-voltage emitter electrode to ionize the air and grounded collector wires. In the video a small-scale version (see top image) was first constructed, demonstrating the effectiveness. Whereas the passive grid collected virtually none of the fog from an ultrasonic fog maker, with 35 kV applied the difference was night and day. No water was collected with the first test, but with power applied a significant 40 mL was collected in 5 minutes on the small mesh.

With this scale test complete, a larger version could be designed and tested. This simplifies the emitter to a single wire connected between two stakes, one of which contains the 20 kV HV generator and battery. The mesh is placed right below it and grounded (see image). With an extreme fog test inside a terrarium, it showed a very strong effect, resulting in a harvest of 14 mL/Wh for this prototype. With a larger scale version in a real-life environment (i.e. desert) planned, it’ll be interesting to see whether this method holds up in a more realistic scenario.

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