The Continuing Venusian Mystery Of Phosphine And Ammonia

The planet Venus is in so many ways an enigma. It’s a sister planet to Earth and also within relatively easy reach of our instruments and probes, yet we nevertheless know precious little about what is going on its surface or even inside its dense atmosphere. Much of this is of course due to planets like Mars getting all the orbiting probes and rovers scurrying around on its barren, radiation-blasted surface, but we had atmospheric probes descend through Venus’ atmosphere, so far to little avail. Back in 2020 speculation arose of phosphine being detected in Venus’ atmosphere, which caused both excitement and a lot of skepticism. Regardless, at the recent National Astronomy Meeting (NAM 2024) the current state of Venusian knowledge was discussed, which even got The Guardian to report on it.

In addition to phosphine, there’s speculation of ammonia also being detectable from Earth, both of which might be indicative of organic processes and thus potentially life. Related research has indicated that common amino acids essential to life on Earth would be stable even in sulfuric droplets like in Venus’ atmosphere. After criticism to the original 2020 phosphine article, [Jane S. Greaves] et al. repeated their observations based on feedback, although it’s clear that the observation of phosphine gas on Venus is not a simple binary question.

The same is true of ammonia, which if present in Venusian clouds would be a massive discovery, which according to research by [William Bains] and colleagues in PNAS could explain many curious observations in Venus’ atmosphere. With so much uncertainty with remote observations, it’s clear that the only way that we are going to answer these questions is with future Venus missions, which sadly remain rather sparse.

If there’s indeed life on Venus, it’ll have a while longer to evolve before we can go and check it out.

Carbon–Cement Supercapacitors Proposed As An Energy Storage Solution

Although most energy storage solutions on a grid-level focus on batteries, a group of researchers at MIT and Harvard University have proposed using supercapacitors instead, with their 2023 research article by [Nicolas Chanut] and colleagues published in Proceedings of the National Academy of Sciences (PNAS). The twist here is that rather than any existing supercapacitors, their proposal involves conductive concrete (courtesy of carbon black) on both sides of the electrolyte-infused insulating membrane. They foresee this technology being used alongside green concrete to become part of a renewable energy transition, as per a presentation given at the American Concrete Institute (ACI).

Functional carbon-cement supercapacitors (connected in series) (Credit: Damian Stefaniuk et al.)

Putting aside the hairy issue of a massive expansion of grid-level storage, could a carbon-cement supercapacitor perhaps provide a way to turn the concrete foundation of a house into a whole-house energy storage cell for use with roof-based PV solar? While their current prototype isn’t quite building-sized yet, in the research article they provide some educated guesstimates to arrive at a very rough 20 – 220 Wh/m3, which would make this solution either not very great or somewhat interesting.

The primary benefit of this technology would be that it could be very cheap, with cement and concrete being already extremely prevalent in construction due to its affordability. As the researchers note, however, adding carbon black does compromise the concrete somewhat, and there are many questions regarding longevity. For example, a short within the carbon-cement capacitor due to moisture intrusion and rust jacking around rebar would surely make short work of these capacitors.

Swapping out the concrete foundation of a building to fix a short is no small feat, but maybe some lessons could be learned from self-healing Roman concrete.

FDM Filament Troubles: Keeping Hygroscopic Materials From Degrading

Despite the reputation of polymers used with FDM 3D printing like nylon, ABS, and PLA as being generally indestructible, they do come with a whole range of moisture-related issues that can affect both the printing process as well as the final result. While the concept of ‘baking’ such 3D printing filaments prior to printing to remove absorbed moisture is well-established and with many commercial solutions available, the exact extent to which these different polymers are affected, and what these changes look like on a molecular level are generally less well-known.

Another question with such hygroscopic materials is whether the same issues of embrittlement, swelling, and long-term damage inflicted by moisture exposure that affects filaments prior to printing affects these materials post-printing, and how this affects the lifespan of FDM-printed items. In a 2022 paper by Adedotun D. Banjo and colleagues much of what we know today is summarized in addition to an examination of the molecular effects of moisture exposure on polylactic acid (PLA) and nylon 6.

The scientific literature on FDM filaments makes clear that beyond the glossy marketing there is a wonderful world of materials science to explore, one which can teach us a lot about how to get good FDM prints and how durable they will be long-term.

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Particle Physics On A Small, Affordable PCB

Experimenting in the world of particle physics probably brings to mind large, expensive pieces of equipment like particle accelerators, or at least exotic elements or isotopes that most of us can’t easily find. But plenty of common objects emit various particles, and it turns out that detecting these particles does not require government backing or acres of test equipment. In fact, you can get this job done with a few readily-available parts and [Tim] shows us how it’s done with his latest project.

The goal of his build is to have a working particle detector for less than $10 per board, although he’s making them in bulk to be used in an educational setting. The board uses a set of photodiodes enclosed in a protective PCB sandwich to detect beta particles from a Potassium-40 source. The high-energy electron interacts with the semiconductor in the photodiode and creates a measurable voltage pulse, which can be detected and recorded by the microcontroller on the board. For this build an RP2040 chip is being used, with a number of layers of amplification between it and the photodetector array used to get signals that the microcontroller can read.

Getting particle physics equipment into the hands of citizen scientists is becoming a lot more common thanks to builds like this which leverage the quirks of semiconductors to do something slightly outside their normal use case, and of course the people building them releasing their projects’ documentation on GitHub. We’ve also seen an interesting muon detector with a price tag of around $100 and an alpha particle detector which uses a copper wire with a high voltage to do its work.

Amputation and wound care behavior in C. floridanus (A) Illustration of a worker providing wound care on a femur-injured individual. (B) A worker amputating (biting) the injured leg at the trochanter. (C) A worker providing wound care on the newly created trochanter wound after amputation. (D) Percentage of amputations performed on ants with an infected or sterile femur (red) or tibia (blue) injury after 24 h. Numbers above the bars represent the sample size for each treatment. (E) Percentage of time the injured ant received wound care behavior over 3 h, binned in 10 min intervals, with a local polynomial regression (loess) showing a 95% confidence interval for the first 3 h after the experimental femur injury (femur, red: n = 8) and the first 3 h after amputation on the trochanter wound (trochanter, brown: n = 7).

Surgery — Not Just For Humans Anymore

Sometimes, a limb is damaged so badly that the only way to save the patient is to amputate it. Researchers have now found that humans aren’t the only species to perform life-saving amputations. [via Live Science]

While some ants have a gland that secretes antimicrobial chemicals to treat wounds in their comrades, Florida carpenter ants have lost this ability over the course of evolution. Lacking this chemical means to treat wounds, these ants have developed the first observed surgery in an animal other than humans.

When an ant has a wounded leg, its fellow ants analyze the damage. If the femur is the site of the wound, the other ants removed the damaged limb in 76% of cases by biting it off, while tibial wounds were treated in other ways. Experimental amputations of the tibia by researchers showed no difference in survivability compared to leaving the limb intact unless the amputation was performed immediately, so it seems the ants know what they’re doing.

Maybe these ants could be helpful surgical aids with some cyborg additions since they’ve already got experience? Ants can help you with programming too if that’s more your speed.

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You Can Build A Little Car That Goes Farther Than You Push It

Can you build a car that travels farther than you push it? [Tom Stanton] shows us that you can, using a capacitor and some nifty design tricks.

[Tom]’s video shows us the construction of a small 3D printed trike with a curious drivetrain. There’s a simple generator on board, which charges a capacitor when the trike is pushed along the ground. When the trike is let go, however, this generator instead acts as a motor, using energy stored in the capacitor to drive the trike further.

When put to the test by [Tom], both a freewheeling car and the capacitor car are pushed up to a set speed. But the capacitor car goes farther. The trick is simple – the capacitor car can go further because it has more energy. But how?

It’s all because more work is being done to push the capacitor car up to speed. It stores energy in the capacitor while it’s being accelerated by the human pushing it. In contrast, after being pushed, the freewheeling car merely coasts to a stop as it loses kinetic energy. However, the capacitor car has similar kinetic energy plus the energy stored in its capacitor, which it can use to run its motor.

It’s a neat exploration of some basic physics, and useful learning if you’ve ever wondered about the prospects of perpetual motion machines.

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PeLEDs: Using Perovskites To Create LEDs Which Also Sense Light

With both of the dominant display technologies today – LCD and OLED – being far from perfect, there is still plenty of room in the market for the Next Big Thing. One of the technologies being worked on is called PeLED, for Perovskite LED. As a semiconductor material, it can both be induced to emit photons as well as respond rather strongly to incoming photons. That is a trick that today’s displays haven’t managed without integrating additional sensors. This technology could be used to create e.g. touch screens without additional hardware, as recently demonstrated by [Chunxiong Bao] and colleagues at Linköping University in Sweden and Nanjing University in China.

Their paper in Nature Electronics describes the construction of photo-responsive metal halide perovskite pixels, covering the typical red (CsPbI3−xBrx), green (FAPbBr3), and blue (CsPbBr3−xClx) wavelengths. The article also describes the display’s photo-sensing ability to determine where a finger is placed on the display. In addition, it can work as an ambient light sensor, a scanner, and a solar cell to charge a capacitor. In related research by [Yun Gao] et al. in Nature Electronics, PeLEDs are demonstrated with 1 microsecond response time.

As usual with perovskites, their lack of stability remains their primary obstacle. In the article by [Chunxiong Bao] et al. the manufactured device with red pixels was reduced to 80% of initial brightness after 18.5 hours. While protecting the perovskites from oxygen, moisture, etc. helps, this inherent instability may prevent PeLEDs from ever becoming commercialized in display technology. Sounds like a great challenge for the next Hackaday Prize!