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#evaporation

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This is an interesting article, worth a full read, on an aspect of Climate not always talked about in much detail.

«… The drying out of soil “increases the severity and frequency” of major droughts …, explains Dr Benjamin Cook, an … Earth system scientist … “Droughts are one of the most impactful, expensive natural hazards out there, because they are typically persistent and long lasting. Everything needs water – ecosystems need water, agriculture needs water. People need water. If you don’t have enough water – you’re in trouble.” … The study points to two factors driving gradual depletion of soil moisture over the last quarter century: fluctuations to rainfall patterns and increasing “evaporative demand”. … the atmosphere’s “thirst” for water …»

When I read about these things, I think of the danger to the food system and human society. It saddens me beyond measure that we've got a society run by capitalists who, like locusts, just want to efficiently consume every last resource the planet has to offer with no apparent regard for the future.

The article also mentions it will be expensive, though. Does that matter to any of you capitalists? I know risk of societal collapse is not a worthy concern to you, just something to monetize. But it could affect prices along the way. Is THAT perhaps a concern, at least? Sigh.

carbonbrief.org/global-soil-mo

Carbon Brief · Global soil moisture in 'permanent' decline due to climate change - Carbon BriefA new study warns that global declines in soil moisture over the 21st century could mark a “permanent” shift in the world’s water cycle.

"A study published in Geophysical Research Letters has challenged the conventional understanding of the relationship between global warming and ocean evaporation. A research team from the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences discovered a phenomenon (called wind stilling) that, despite rising sea surface temperatures, global ocean evaporation has decreased over the past decade".

#globalwarming #evaporation
phys.org/news/2025-02-scientis

Phys.org · Scientists discover unexpected decline in global ocean evaporation amid rising sea temperaturesBy Li Yali

“My Own Galaxy”

Fungal spores sketch out minute air currents in this shortlisted photograph by Avilash Ghosh. The moth atop a mushroom appears to admire the celestial view. In the largely still air near the forest floor, mushrooms use evaporation and buoyancy to generate air flows capable of lifting their spores high enough to catch a stray breeze. (Image credit: A. Ghosh/CUPOTY; via Colossal)

Quick-Drying, Fast-Cracking

Water droplets filled with nanoparticles leave behind deposits as they evaporate. Like a coffee ring, particles in the evaporating droplet tend to gather at the drop’s edge (left). As the water evaporates, the deposit grows inward (center) and cracks start to form radially. After just a couple minutes, the solid deposit covers the entire area of the original droplet and is shot through with cracks (right).

Researchers found that the cracks’ patterns and propagation are predictable through a model that balances the local elastic energy and and the energy cost of fracture. They also found that the spacing between radial cracks depends on the deposit’s local thickness. Besides explaining the patterns seen here, these cracking models could help analyze old paintings, where cracks could hide information about the artist’s methods and the artwork’s condition. (Image and research credit: P. Lilit et al.; via Physics Today)

The Mystery of the Binary Droplet

What goes on inside an evaporating droplet made up of more than one fluid? This is a perennially fascinating question with lots of permutations. In this one, researchers observed water-poor spots forming around the edges of an evaporating drop, almost as if the two chemicals within the drop are physically separating from one another (scientifically speaking, “undergoing phase separation“). To find out if this was really the case, they put particles into the drop and observed their behavior as the drop evaporated. What they found is that this is a flow behavior, not a phase one. The high concentration of hexanediol near the edge of the drop changes the value of surface tension between the center and edge of the drop. And that change is non-monotonic, meaning that there’s a minimum in the surface tension partway along the drop’s radius. That surface tension minimum is what creates the separated regions of flow. (Video and image credit: P. Dekker et al.; research pre-print: C. Diddens et al.)

How Cooling Towers Work

Power plants (and other industrial settings) often need to cool water to control plant temperatures. This usually requires cooling towers like the iconic curved towers seen at nuclear power plants. Towers like these use little to no moving parts — instead relying cleverly on heat transfer, buoyancy, and thermodynamics — to move and cool massive amounts of water. Grady breaks them down in terms of operation, structural engineering, and fluid/thermal dynamics in this Practical Engineering video. Grady’s videos are always great, but I especially love how this one tackles a highly visible piece of infrastructure from multiple engineering perspectives. (Video and image credit: Practical Engineering)

Active Cheerios Self-Propel

The interface where air and water meet is a special world of surface-tension-mediated interactions. Cereal lovers are well-aware of the Cheerios effect, where lightweight O’s tend to attract one another, courtesy of their matching menisci. And those who have played with soap boats know that a gradient in surface tension causes flow. Today’s pre-print study combines these two effects to create self-propelling particle assemblies.

The team 3D-printed particles that are a couple centimeters across and resemble a cone stuck atop a hockey puck. The lower disk area is hollow, trapping air to make the particle buoyant. The cone serves as a fuel tank, which the researchers filled with ethanol (and, in some cases, some fluorescent dye to visualize the flow). Like soap, ethanol’s lower surface tension disrupts the water’s interface and triggers a flow that pulls the particle toward areas with higher surface tension. But, unlike soap, ethanol evaporates, effectively restoring the interface’s higher surface tension over time.

With multiple self-propelling particles on the interface, the researchers observed a rich series of interactions. Without their fuel, the Cheerios effect attracted particles to each other. But with ethanol slowly leaking out their sides, the particles repelled each other. As the ethanol ran out and evaporated, the particles would again attract. By tweaking the number and position of fuel outlets on a particle, the researchers found they could tune the particles’ attractions and motility. In addition to helping robots move and organize, their findings also make for a fun educational project. There’s a lot of room for students to play with different 3D-printed designs and fuel concentrations to make their own self-propelled particles. (Research and image credit: J. Wilt et al.; via Ars Technica)

It might seem counterintuitive, but #evaporation over the #GreatLakes is greatest in the late fall and early winter. This is because the water is so much warmer (relatively) than the air, and the #lakes can lose 13 mm (0.5 in) of water per day, equal to 20 Niagara Falls. The recent 20C difference between Lake #Ontario and the air created widespread "steam devils" vapour plumes. Lake Ontario has the highest #ClimateChange mediated decline in ice coverage (88%). #Science
theweathernetwork.com/en/news/

“There is a crack in everything…”

When millimeter-sized drops of water infused with nanoparticles dry, they leave behind complex and beautiful residues. As water continues evaporating, the residues warp, bend, and crack. In this video, researchers set their science to the music of Leonard Cohen. The results resemble blooming flowers and flying water fowl. If you’d like to learn more about the science behind the art, check out the two open-access papers linked below. (Video and image credit: P. Lilin and I. Bischofberger; submitted by Irmgard B.; see also P. Lilin and I. Bischofberger and P. Lilin et al.)

Replied in thread

Hello!
Evaporation est un poème de Nicolas Montès autour duquel j'ai auto édité l'ouvrage du même nom : 9 reproductions photographiques, un poème, un texte de présentation, glissés dans une pochette fourreau dessinée, manufacturée et assemblée par mes soins.
La V2 est disponible en une vingtaine d'exemplaires pour 25 euros!

Infos ici et là :
simonbezzibatani.fr/art/evapor
simonbezzibatani.fr/shop/

Replied in thread

Hello!
Evaporation est un poème de Nicolas Montès autour duquel j'ai auto édité l'ouvrage du même nom : 9 reproductions photographiques, un poème, un texte de présentation glissés dans une pochette fourreau dessinée, manufacturée et assemblée par mes soins.
La V2 est disponible en une vingtaine d'exemplaires pour 25 euros!

Infos ici et là :
simonbezzibatani.fr/art/evapor
simonbezzibatani.fr/shop/