Science

1439 Articles

Conductive Ink Based On A Simple Idea

January 14, 2023 by 15 Comments

There’s an old series of jokes that starts with: “How do you put an elephant in a refrigerator?” The answer is to open the door, put the elephant inside, and close the door. Most people don’t get that because it is too simple, and simple is the approach Georgia Tech researchers have taken when faced with the problem of using a particular conductive plastic. PEDOT, the plastic in question, is a good conductor, but it is hard to work with. You can add materials to make it easier to work with, but that screws up the conductivity. Their answer is much like the refrigerator joke: add material to PEDOT, paint or print it where you want, and then remove the extra material. Simple.

The polymer needs side chains to be soluble. This allows you to mix an ink or paint made of the material, but the waxy side chains interfere with the material’s conductivity. However, after application, it is possible to break off the side chains and flush them out with a common solvent. The process is simple, and leaves a flexible conductive material that’s stable.

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NASA Help Wanted: Telescope Optional

January 11, 2023 by 31 Comments

If you’ve ever wanted to work for NASA, here’s your chance. Well, don’t expect a paycheck or any benefits, but the Agency is looking for volunteers to help process the huge amount of exoplanet data with their Exoplanet Watch program. If you have a telescope, you can even contribute data to the project. But if your telescope is in the back closet, you can process data they’ve collected over the years.

You might think the only way to contribute with a telescope is to have a mini-observatory in your backyard, but that’s not the case. According to NASA, even a six-inch telescope can detect hundreds of exoplanet transits using their software. You might not get paid, but the program’s policy requires that the first paper to use work done by program volunteers will receive co-author credit on the paper. Not too shabby!

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The Intricacies Of Creating Fuel For Nuclear Reactors

January 10, 2023 by 51 Comments

All nuclear fission power reactors run on fuel containing uranium and other isotopes, but fueling a nuclear reactor is a lot more complicated than driving up to them with a dump truck filled with uranium ore and filling ‘er up. Although nuclear fission is simple enough that it can occur without human intervention as happened for example at the Oklo natural fission reactors, within a commercial reactor the goal is to create a nuclear chain reaction that targets a high burn-up (fission rate), with an as constant as possible release of energy.

Each different fission reactor design makes a number of assumptions about the fuel rods that are inserted into it. These assumptions can be about the enrichment ratio of the fissile isotopes like U-235, the density of individual fuel pellets, the spacing between the fuel rods containing these pellets, the configuration of said fuel rods along with any control, moderator and other elements. and so on.

Today’s light water reactors, heavy water reactors, fast neutron reactors, high temperature reactors and kin all have their own fuel preferences as a result, with high-assay low-enriched (HALEU) fuel being the new hot thing for new reactor designs. Let’s take a look at what goes into these fuel recipes.

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Tiny Robots That Bring Targeted Drug Delivery And Treatment A Little Bit Closer

January 7, 2023 by 8 Comments

Within the world of medical science fiction they are found everywhere: tiny robots that can zip through blood vessels and intestines, where they can deliver medication, diagnose medical conditions and even directly provide treatment. Although much of this is still firmly in the realm of science-fiction, researchers at Stanford published work last year on an origami-based type of robots, controlled using an external magnetic field. Details can be found in the Nature Communications paper. Continue reading “Tiny Robots That Bring Targeted Drug Delivery And Treatment A Little Bit Closer” →

Salty Refrigeration Is Friendly To The Environment

January 6, 2023 by 34 Comments

Widespread use of refrigerators is a hallmark of modern society, allowing people to store food and enjoy ice and cold beverages. However, a typical refrigerator uses gasses that are not always good for the environment. Now the Berkeley National Lab says they can change that using ioncaloric cooling, a new technique that uses salt as a refrigerant.

The new technique involves using ions to drive a solid-to-liquid phase change which is endothermic. Unlike some similar proposals, the resulting liquid material would be easy to pump through a heat exchanger. In simple terms, it is the same process as salting a road to change the melting point of ice. In this case, an iodine-sodium salt and an organic solvent combine. Passing current through the material moves ions which changes the material’s melting point. When it melts, it absorbs heat. When it resolidifies, it releases heat.

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A notated illustration showing how a mycelial network may be functionalized as a PCB substrate. The process starts with Cu vapor deposition onto the network followed by Au either by more vapor deposition or electrodeposition. Traces are then cut via laser ablation.

MycelioTronics: Biodegradable Electronics Substrates From Fungi

January 6, 2023 by 12 Comments

E-waste is one of the main unfortunate consequences of the widespread adoption of electronic devices, and there are various efforts to stem the flow of this pernicious trash. One new approach from researchers at the Johannes Kepler University in Austria is to replace the substrate in electronics with a material made from mycelium skins.

Maintaining performance of ICs and other electronic components in a device while making them biodegradable or recyclable has proved difficult so far. The substrate is the second largest contributor (~37% by weight) to the e-waste equation, so replacing it with a more biodegradable solution would still be a major step toward a circular economy.

To functionalize the mycelial network as a PCB substrate, the network is subjected to Physical Vapor Deposition of copper followed by deposition of gold either by more PVD or electrodeposition. Traces are then cut via laser ablation. The resulting substrate is flexible and can withstand over 2000 bending cycles, which may prove useful in flexible electronics applications.

If you’re looking for more fun with fungi, check out these mycelia bricks, this fungus sound absorber, or this mycellium-inspired mesh network.

A White-Light Laser, On The Cheap

January 4, 2023 by 51 Comments

Lasers are known for the monochromatic nature of their light, so much so that you might never have thought there could be such a thing as a white laser. But in the weird world of physics, a lot of things that seem impossible aren’t really, as demonstrated by this dirt-cheap supercontinuum laser.

Of course, we’re not experts on lasers, and certainly not on non-linear optics, so we’ll rely on [Les Wright]’s video below to explain what’s going on here. Basically, a “supercontinuum” is just the conversion of a monochromatic source to a broader spectral bandwidth. It’s a non-linear optical process that’s usually accomplished with expensive bits of kit, like photonic crystal fibers, which are optical fibers with an array of tiny air-filled holes running down their lengths. Blast a high-intensity monochromatic laser down one end, and white light comes out the other end.

Such fibers are obviously fantastically expensive, so [Les] looked back in the literature and found that a simple silica glass single-mode fiber could be used to produce a supercontinuum. As luck would have it, he had been experimenting with telecom fibers recently, so along with a nitrogen laser he recovered from a Dumpster, he had pretty much everything he needed. The final setup uses the UV laser to pump a stilbene dye laser, which shoots a powerful pulse of 426 nanometer light into about 200 meters of fiber, and produces a gorgeous supercontinuum containing light from 430 nm to 670 nm — pretty much the entire visible spectrum.

It’s great to see projects like this that leverage low-cost, easy-to-source equipment to explore esoteric physics concepts.

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