Detecting Helium Leaks With Sound In A Physics-Based Sensor

February 4, 2026 by Donald Papp 11 Comments

Helium is inert, which makes it useful in a lot of different industries. But helium’s colorless and odorless non-reactivity also means traditional gas sensing methods don’t work. Specialized detectors exist, but are expensive and fussy. Thankfully, researcher [Li Fan] and colleagues found a physics-based method of detecting helium that seems as elegant as it is simple.

The new sensor relies on a topological kagome structure, and doesn’t depend on any chemical reaction or process whatsoever. The cylinders in the structure are interconnected; air can flow in and speakers at the three corners inject sound.

Sound waves propagate through the air within the structure at a fixed rate, and as helium enters the sensor it changes how fast the sound waves travel. This measurable shift in vibration frequency indicates the concentration of helium. It’s stable, calibration-free, doesn’t care much about temperature, and resets quickly. Even better, the three corners act as separate sensors, making it directional. It’s even quite rugged. Just as a basket weaved in a kagome pattern is stable and resistant to damage or imperfections in the individual strips that make up the pattern, so too is this sensor only marginally affected by physical defects.

The sensor design has been tested and shown to work with helium, but could possibly be applied to other gases. More detail is available at ResearchGate, with some information about the math behind it all in a supplemental paper.

Optical Combs Help Radio Telescopes Work Together

February 3, 2026 by Maya Posch No comments

Very-long baseline interferometry (VLBI) is a technique in radio astronomy whereby multiple radio telescopes cooperate to bundle their received data and in effect create a much larger singular radio telescope. For this to work it is however essential to have exact timing and other relevant information to accurately match the signals from each individual radio telescope. As VLBI is used for increasingly higher ranges and bandwidths this makes synchronizing the signals much harder, but an optical frequency comb technique may offer a solution here.

In the paper by [Minji Hyun] et al. it’s detailed how they built the system and used it with the Korean VLBI Network (VLB) Yonsei radio telescope in Seoul as a proof of concept. This still uses the same hydrogen maser atomic clock as timing source, but with the optical transmission of the pulses a higher accuracy can be achieved, limited only by the photodiode on the receiving end.

In the demonstration up to 50 GHz was possible, but commercial 100 GHz photodiodes are available. It’s also possible to send additional signals via the fiber on different wavelengths for further functionality, all with the ultimate goal of better timing and adjustment for e.g. atmospheric fluctuations that can affect radio observations.

Thomas Edison May Have Discovered Graphene

January 31, 2026 by Al Williams 13 Comments

Thomas Edison is well known for his inventions (even if you don’t agree he invented all of them). However, he also occasionally invented things he didn’t understand, so they had to be reinvented again later. The latest example comes from researchers at Rice University. While building a replica light bulb, they found that Thomas Edison may have accidentally created graphene while testing the original article.

Today, we know that applying a voltage to a carbon-based resistor and heating it up to over 2,000 °C can create turbostratic graphene. Edison used a carbon-based filament and could heat it to over 2,000 °C.

This reminds us of how, in the 1880s, Edison observed current flowing in one direction through a test light bulb that included a plate. However, he thought it was just a curiosity. It would be up to Fleming, in 1904, to figure it out and understand what could be done with it.

Naturally, Edison wouldn’t have known to look for graphene, how to look for it, or what to do with it if he found it. But it does boggle the mind to think about graphene appearing many decades earlier. Or maybe it would still be looking for a killer use. Certainly, as the Rice researchers note, this is one of the easier ways to make graphene.

Building Natural Seawalls To Fight Off The Rising Tide

January 30, 2026 by Lewin Day 40 Comments

These days, the conversation around climate change so often focuses on matters of soaring temperatures and extreme weather events. While they no longer dominate the discourse, rising sea levels will nonetheless still be a major issue to face as global average temperatures continue to rise.

This poses unique challenges in coastal areas. Municipalities must figure out how to defend their shorelines, or decide which areas they’re willing to lose. The City of Palo Alto is facing just this challenge, and is building a natural kind of seawall to keep the rising tides at bay.

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Rare-Earth-Free Magnets With High Entropy Borides

January 29, 2026 by Maya Posch 15 Comments

Map of the calculated magnetic anisotropy. (Credit: Beeson et al., Adv. Mat., 2025)

Although most of us simultaneously accept the premise that magnets are quite literally everywhere and that few people know how they work, a major problem with magnets today is that they tend to rely on so-called rare-earth elements.

Although firmly in the top 5 of misnomers, these abundant elements are hard to mine and isolate, which means that finding alternatives to their use is much desired. Fortunately the field of high entropy alloys (HEAs) offers hope here, with [Beeson] and colleagues recently demonstrating a rare-earth-free material that could be used for magnets.

Although many materials can be magnetic, to make a good magnet you need the material in question to be both magnetically anisotropic and posses a clear easy axis. This basically means a material that has strong preferential magnetic directions, with the easy axis being the orientation which is the most energetically favorable.

Through experimental validation with magnetic coercion it was determined that of the tested boride films, the (FeCoNiMn)₂B variant with a specific deposition order showed the strongest anisotropy. What is interesting in this study is how much the way that the elements are added and in which way determines the final properties of the boride, which is one of the reasons why HEAs are such a hot topic of research currently.

Of course, this is just an early proof-of-concept, but it shows the promise of HEAs when it comes to replacing other types of anisotropic materials, in particular where – as noted in the paper – normally rare-earths are added to gain the properties that these researchers achieved without these elements being required.

Did We Overestimate The Potential Harm From Microplastics?

January 29, 2026 by Maya Posch 55 Comments

Over the past years there have appeared in the media increasingly more alarming reports about micro- and nanoplastics (MNPs) and the harm that they are causing not only in the environment, but also inside our bodies. If some of the published studies were to be believed, then MNPs are everywhere inside our bodies, from our blood and reproductive organs to having deeply embedded themselves inside our brains with potentially catastrophic health implications.

Early last year we covered what we thought we knew about the harm from MNPs in our bodies, but since then more and more scientists have pushed back against these studies, calling them ‘flawed’ and questioning the used methodology and conclusions. Despite claims of health damage in mice, institutions like the German federal risk assessment institute also do not acknowledge evidence of harm to human health from MNPs.

All of which raises the question whether flawed studies have pushed us into our own Chicken Little moment, and whether it’s now time to breathe a sigh of relief that the sky isn’t falling after all.

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The Amazing Maser

January 28, 2026 by Al Williams 47 Comments

While it has become a word, laser used to be an acronym: “light amplification by stimulated emission of radiation”. But there is an even older technology called a maser, which is the same acronym but with light switched out for microwaves. If you’ve never heard of masers, you might be tempted to dismiss them as early proto-lasers that are obsolete. But you’d be wrong! Masers keep showing up in places you’d never expect: radio telescopes, atomic clocks, deep-space tracking, and even some bleeding-edge quantum experiments. And depending on how a few materials and microwave engineering problems shake out, masers might be headed for a second golden age.

Simplistically, the maser is — in one sense — a “lower frequency laser.” Just like a laser, stimulated emission is what makes it work. You prepare a bunch of atoms or molecules in an excited energy state (a population inversion), and then a passing photon of the right frequency triggers them to drop to a lower state while emitting a second photon that matches the first with the same frequency, phase, and direction. Do that in a resonant cavity and you’ve got gain, coherence, and a remarkably clean signal.

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