Measuring Trees Via Satellite Actually Takes A Great Deal Of Field Work

February 20, 2024 by Lewin Day 11 Comments

Figuring out what the Earth’s climate is going to do at any given point is a difficult task. To know how it will react to given events, you need to know what you’re working with. This requires an accurate model of everything from ocean currents to atmospheric heat absorption and the chemical and literal behavior of everything from cattle to humans to trees.

In the latter regard, scientists need to know how many trees we have to properly model the climate. This is key, as trees play a major role in the carbon cycle by turning carbon dioxide into oxygen plus wood. But how do you count trees at a continental scale? You’ll probably want to get yourself a nice satellite to do the job.

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Gold Recovery From E-Waste With Food-Waste Amyloid Aerogels

February 20, 2024 by Maya Posch 11 Comments

A big part of the recycling of electronic equipment is the recovery of metals such as gold. Usually the printed circuit boards and other components are shredded, sorted, and then separated. But efficiently filtering out specific metals remains tricky and adds to the cost of recycling. A possible way to optimize the recovery of precious metals like gold could be through the use of aerogels composed out of protein amyloids to which one type of metal would preferentially adsorb. According to a recent research article in Advanced Materials by [Mohammad Peydayesh] and colleagues, such aerogels could be created from protein waste from the food industry.

The adsorption mechanism of the protein amyloids is a feature of these proteins which form chelants, which are structures that can effectively bond to metal ions. These are usually organic compounds, and are used in certain medical treatments where heavy metal poisoning is involved (chelation therapy). By having these protein amyloids in an aerogel structure, the surface area for adsorption is maximized, which in the research article is said to have an efficiency of 93.3% for gold recovery, while leaving the other metals in the aqua regia solution (nitric and hydrochloric acid) mostly untouched.

Of note here is that although the food waste protein angle is taken, the experiment used whey protein. This is also one of the most popular food supplements in the world, to the point that microbial production of whey is a thing now. Although this doesn’t invalidate the aerogel chelation approach to e-waste recycling, it’s a curious omission in the article that does not appear to be addressed.

ForceGen: Using A Diffusion Model To Help Design Novel Proteins

February 19, 2024 by Maya Posch 1 Comment

Although proteins are composed out of only a small number of distinct amino acids, this deceptive simplicity quickly vanishes when considering the many possible sequences across a protein, not to mention the many ways in which a single 1D protein sequence can fold into a 3D protein shape with a specific functionality. Although natural evolution has done much of the legwork here already, figuring out new sequences and their functionality is a daunting task where increasingly deep learning algorithms are being applied. As [Bo Ni] and colleagues report in a research article in Science Advances, the hardest challenge is designing a protein sequence based on the desired functionality. They then demonstrate a way to use a generative model to speed up this process.

They set out to design proteins with specific mechanical properties, for which they used the known unfolding characteristics of various protein sequences to train a diffusion model. This approach is thus more akin to the technology behind image generation algorithms like DALL-E than LLMs. Using the trained diffusion model it was then possible to generate likely sequences of which the properties could then be simulated, with favorable results.

As a large data set aid, such a diffusion model could conceivably be very useful in fields even beyond protein synthesis, automating tedious tasks and conceivably speeding up discoveries.

Low-Cost Saliva-based Biosensor For Cancer Detection

February 18, 2024 by Maya Posch 12 Comments

More and more biomarkers that can help in the early diagnosis of diseases like cancer are being discovered every year, but often the effective application relies on having diagnostic methods that are both affordable and as least invasive as possible. This is definitely true in the case of breast cancers, where the standard diagnostic method after seeing something ‘odd’ on a scan is to perform a biopsy so that a tissue sample can be tested in a laboratory. What [Hsiao-Hsuan Wan] and colleagues demonstrate in a recently published research article in the Journal of Vacuum Science & Technology B is a way to use saliva on disposable test strips to detect the presence of cancer-related biomarkers. Best of all, the system could be very affordable.

The two biomarkers tested in this experiment are HER2 (in 10 – 30% of breast cancer cases) and CA 15-3, both of which are indicative of a variety of cancers, including breast cancers. According to the researchers, the levels of these biomarkers in saliva can be correlated to those in blood serum. Where other biosensors may include the read-out circuitry – making those disposable and expensive – here the disposable part is the test strips which are plated with electrodes.

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Canned Air Is Unexpectedly Supersonic

February 18, 2024 by Donald Papp 18 Comments

How fast is the gas coming out from those little duster tubes of canned air? Perhaps faster than one might think! It’s supersonic (video, embedded below) as [Cylo’s Garage] shows by imaging clear shock diamonds in the flow from those thin little tubes.

Shock diamonds are a clear indicator of supersonic flow.

Shock diamonds, normally seen in things like afterburning jet turbine or rocket engine exhaust streams, are the product of standing wave patterns that indicate supersonic speeds. These are more easily visible in jet plumes, but [Cylo’s Garage] managed to get some great images of the same phenomenon in more everyday things such as the flow of duster gas.

Imaging this is made possible thanks to what looks like a simple but effective Sch lieren imaging setup, which is a method of visualizing normally imperceptible changes in a fluid’s refractive index. Since the refractive index of a gas can change in response to density, pressure, or temperature, it’s a perfect way to see what’s going on when there’s otherwise nothing for one’s eyeballs to latch onto.

Intrigued by this kind of imaging? It requires a careful setup, but nothing particularly complicated or hard to get a hold of. Here’s one such setup, here’s a Schlieren videography project, and here’s a particularly intriguing approach that leverages modern electronics like a smartphone.

Thanks to [Quinor] for the tip!

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Metal 3D Printing Gets Really Fast (and Really Ugly)

February 17, 2024 by Donald Papp 8 Comments

The secret to cranking out a furniture-sized metal frame in minutes is Liquid Metal Printing (LMP), demonstrated by researchers at the Massachusetts Institute of Technology. They’ve demonstrated printing aluminum frames for tables and chairs, which are perfectly solid and able to withstand post-processing like drilling and milling.

The system heats aluminum in a graphite crucible, and the molten metal is gravity-fed through a ceramic nozzle and deposited into a bed of tiny 100-micron glass beads. The beads act as both print bed and support structure, allowing the metal to cool quickly without really affecting the surface. Molten aluminum is a harsh material to work with, so both the ceramic nozzle material and the glass beads to fill the print bed were selected after a lot of testing.

This printing method is fast and scalable, but sacrifices resolution. Ideally, the team would love to make a system capable of melting down recycled aluminum to print parts with. That would really be something new and interesting when it comes to manufacturing.

The look of the printed metal honestly reminds us a little of CandyFab from [Windell Oskay] and [Lenore Edman] at Evil Mad Scientist, which was a 3D printer before hobbyist 3D printers or kits were really a thing. CandyFab worked differently — it used hot air to melt sugar together one layer at a time — but the end result has a similar sort of look to it. Might not be pretty, but hey, looks aren’t everything.

(Update: see it in action in this video, which is also embedded just below. Thanks [CityZen] for sharing in the comments!)

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Shuji Nakamura: The Man Who Gave Us The Blue LED Despite All Odds

February 14, 2024 by Maya Posch 68 Comments

With the invention of the first LED featuring a red color, it seemed only a matter of time before LEDs would appear with other colors. Indeed, soon green and other colors joined the LED revolution, but not blue. Although some dim prototypes existed, none of them were practical enough to be considered for commercialization. The subject of a recent [Veritasium] video, the core of the problem was that finding a material with the right bandgap and other desirable properties remained elusive. It was in this situation that at the tail end of the 1980s a young engineer at Nichia in Japan found himself pursuing a solution to this conundrum.

Although Nichia was struggling at the time due to the competition in the semiconductor market, its president was not afraid to take a gamble on a promise, which is why this young engineer – [Shuji Nakamura] – got permission to try his wits at the problem. This included a year long study trip to Florida to learn the ins and outs of a new technology called metalorganic chemical vapor deposition (MOCVD, also metalorganic vapor-phase epitaxy). Once back in Japan, he got access to a new MOCVD machine at Nichia, which he quickly got around to heavily modifying into the now well-known two-flow reactor version which improves the yield.

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