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posted by hubie on Saturday November 04 2023, @10:45PM   Printer-friendly

https://techxplore.com/news/2023-10-evaporate-enable-approaches-desalination.html

Evaporation is happening all around us all the time, from the sweat cooling our bodies to the dew burning off in the morning sun. But science's understanding of this ubiquitous process may have been missing a piece all this time.

In recent years, some researchers have been puzzled upon finding that water in their experiments, which was held in a sponge-like material known as a hydrogel, was evaporating at a higher rate than could be explained by the amount of heat, or thermal energy, that the water was receiving. The excess has been significant—a doubling, or even a tripling or more, of the theoretical maximum rate.

After carrying out a series of new experiments and simulations, and reexamining some of the results from various groups that claimed to have exceeded the thermal limit, a team of researchers at MIT has reached a startling conclusion: Under certain conditions, at the interface where water meets air, light can directly bring about evaporation without the need for heat, and it actually does so even more efficiently than heat. In these experiments, the water was held in a hydrogel material, but the researchers suggest that the phenomenon may occur under other conditions as well.

Journal Reference:
Yaodong Tu, Jiawei Zhou, Shaoting Lin, and Gang Chen, Plausible photomolecular effect leading to water evaporation exceeding the thermal limit, PNAS, 120 (45) e2312751120 https://doi.org/10.1073/pnas.2312751120


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  • (Score: 1, Troll) by Mojibake Tengu on Saturday November 04 2023, @10:55PM (4 children)

    by Mojibake Tengu (8598) on Saturday November 04 2023, @10:55PM (#1331485) Journal

    This principle looks like a perfect option for a laser weapon against all kind of living things.

    Did AIs read the article yet?

    --
    Rust programming language offends both my Intelligence and my Spirit.
    • (Score: 4, Funny) by Opportunist on Saturday November 04 2023, @11:34PM

      by Opportunist (5545) on Saturday November 04 2023, @11:34PM (#1331486)

      Yes I did.

      But thanks for asking, meatbag.

    • (Score: 1) by khallow on Sunday November 05 2023, @01:26AM

      by khallow (3766) Subscriber Badge on Sunday November 05 2023, @01:26AM (#1331492) Journal

      This principle looks like a perfect option for a laser weapon against all kind of living things.

      I imagine that it's only good on hydrogels and similar materials. You need something with a lot of surface area to evaporate.

      They began to suspect that the excess evaporation was being caused by the light itself—that photons of light were actually knocking bundles of water molecules loose from the water's surface. This effect would only take place right at the boundary layer between water and air, at the surface of the hydrogel material—and perhaps also on the sea surface or the surfaces of droplets in clouds or fog.

      Also, water vaporization doesn't stop being endothermic. So energy still has to go into that from somewhere.

    • (Score: 2, Funny) by Anonymous Coward on Sunday November 05 2023, @02:05AM (1 child)

      by Anonymous Coward on Sunday November 05 2023, @02:05AM (#1331494)

      Perfect weapon?? It sounds like a Dr. Doofenschmirtz inator:

      Dr. Doofenshmirtz: Ah, Perry the Platypus, there you are! I've been eagerly waiting for your arrival. You see, I've concocted a scheme of diabolical proportions that will leave the entire Tri-State Area parched and chapped!

      Perry the Platypus: (Chattering noise)

      Dr. Doofenshmirtz: Oh, I'm glad you asked. I've developed the "Chapinator" – a laser that will evaporate the moisture right out of people's lips! Once the moisture is gone, their lips will become dry and cracked, causing discomfort and irritation!

      Perry the Platypus: (Raises an eyebrow)

      Dr. Doofenshmirtz: Yes, yes, Perry the Platypus, I'm aware it sounds oddly specific, but let me tell you, it's genius! To make my plan even more nefarious, I've bought up every last bit of lip balm in the Tri-State Area! No one will be able to soothe their chapped lips. Mwahahaha!

      Perry the Platypus: (Shakes his head)

      Dr. Doofenshmirtz: What? You think I'm overcomplicating things? Nonsense! It's a brilliant plan! And when people's lips are all chapped and dry, they'll be too distracted to stop me from taking over the Tri-State Area!

  • (Score: 5, Interesting) by sonamchauhan on Sunday November 05 2023, @01:21AM

    by sonamchauhan (6546) on Sunday November 05 2023, @01:21AM (#1331490)

    The book 'The fourth phase of water' may have some concepts that explain the effect here.

    Basically, infrared light leads to water forming zones where normal water transforms into gel-like material, due to charge separation. This is the 'fourth phase' of water.

    Book review: https://www.goodreads.com/book/show/17930467-the-fourth-phase-of-water [goodreads.com]

  • (Score: 3, Interesting) by Ken_g6 on Sunday November 05 2023, @02:41AM

    by Ken_g6 (3706) on Sunday November 05 2023, @02:41AM (#1331496)

    Dishwashers would still have to heat up to sanitize dishes, but green LEDs might make the drying process take half the time!

  • (Score: 0) by Anonymous Coward on Sunday November 05 2023, @02:27PM (1 child)

    by Anonymous Coward on Sunday November 05 2023, @02:27PM (#1331539)

    Now if only we could make light without heat.

    • (Score: 2) by ledow on Monday November 06 2023, @08:53AM

      by ledow (5567) on Monday November 06 2023, @08:53AM (#1331626) Homepage

      Welcome to LEDs and lasers.

      Sure, they generate *some* heat, but nowhere near enough to evaporate large amounts of water quickly.

  • (Score: 2) by VLM on Monday November 06 2023, @01:11PM

    by VLM (445) Subscriber Badge on Monday November 06 2023, @01:11PM (#1331638)

    The researchers found that the effect varied with color and peaked at a particular wavelength of green light.

    I was not expecting to read that. Sounded like some kind of UV ionization effect until that line.

    using the phase change to provide a highly efficient solar cooling system

    If you can "magically" force water to evaporate, then the water will drop below the dew point, which "should be" impossible but here we are. Separating the vapor from the liquid will be tricky as it will naturally want to condense back into the water. Big fans? Given an infinitely powerful system in a windy environment with plenty of water, you should be able to make an ice skating rink on the pond in the summer. Or freeze an iceberg so you can drill a hole in it to go ice fishing in summer.

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