#electrical field

[fuckyeahfluiddynamics]

Charged Drops Don't Splash

When a droplet falls on a surface, it spreads itself horizontally into a thin lamella. Sometimes -- depending on factors like viscosity, impact speed, and air pressure -- that drop splashes, breaking up along its edge into myriad smaller droplets. But a new study finds that a small electrical charge is enough to suppress a drop's splash. (Image and research credit: F. Yu et al.; via APS News) Read the full article

[eretzyisrael]

Electrical activity in living organisms mirrors electrical fields in atmosphere

(Photo Credit: CC0 Public Domain)

Most electrical activity in vertebrates and invertebrates occurs at extremely low frequencies, and the origin—and medical potential—of these frequencies have eluded scientists. Now a Tel Aviv University study provides evidence for a direct link between electrical fields in the atmosphere and those found in living organisms, including humans.                                                                                          

The study's findings may change established notions about electrical activity in living organisms, paving the way for revolutionary, new medical treatments. Illnesses such as epilepsy and Parkinson's are related to abnormalities in the electrical activity of the body.

"We show that the electrical activity in many living organisms—from zooplankton in the oceans, to sharks and even in our brains—is very similar to the electrical fields we measure and study in the atmosphere from global lightning activity," explains Prof. Colin Price of TAU's Porter School of the Environment and Earth Sciences, who led the research for the study, published in the International Journal of Biometeorology on February 8.

Colleagues from the Massachusetts Institute of Technology and the University of Alaska also contributed to the study.

"We hypothesize that over evolutionary timescales living organisms adapted and evolved to actually use the electricity in the environment—global lightning," Prof. Price continues. "This has likely not changed over billions of years and is similar to the evolution of our eyes, which evolved using the sunlight nature gave us."

As living organisms evolved over billions of years, the natural electromagnetic resonant frequencies in the atmosphere, continuously generated by global lightning activity, provided the background electric fields for the development of cellular electrical activity. Prof. Price's research found that, in some animals, the electrical spectrum is difficult to differentiate from the background atmospheric electric field produced by lightning.

"Neither biologists nor doctors can explain why the frequencies in living organisms (0-50 Hz) are similar to those in the atmosphere caused by lightning," adds Prof. Price. "Most of them are not even aware of the similarity we presented in our paper."

"Our review of previous studies revealed that lightning-related fields may have positive medical applications related to our biological clock (circadian rhythms), spinal cord injuries and maybe other bodily functions related to electrical activity in our bodies," says Prof. Price. "The connection between the ever-present electromagnetic fields, between lightning in the atmosphere and human health, may have huge implications in the future for various treatments related to electrical abnormalities in our bodies."

The study comprised a retrospective review of previous studies on the link between lightning-related fields in the atmosphere and human and animal health. "We collected many different studies over the years to build a clear picture of this link," concludes Prof. Price. "Going forward, we need to design new experiments to see how these extremely low frequency fields from lightning may impact living organisms, and to investigate how these fields can be used to benefit us. One new experiment we are now planning is to see how these fields may impact the rate of photosynthesis in plants."                                                                                                                        

[theemperorsfeather]

Scientists are finally starting to understand the centuries-old mystery of “ballooning.”

This is amazing.

It is commonly believed that ballooning works because the silk catches on the wind, dragging the spider with it. But that doesn’t entirely make sense, especially since spiders only balloon during light winds. Spiders don’t shoot silk from their abdomens, and it seems unlikely that such gentle breezes could be strong enough to yank the threads out—let alone to carry the largest species aloft, or to generate the high accelerations of arachnid takeoff. Darwin himself found the rapidity of the spiders’ flight to be “quite unaccountable” and its cause to be “inexplicable.”

But Erica Morley and Daniel Robert have an explanation. The duo, who work at the University of Bristol, has shown that spiders can sense the Earth’s electric field, and use it to launch themselves into the air.

...

Ballooning spiders operate within this planetary electric field. When their silk leaves their bodies, it typically picks up a negative charge. This repels the similar negative charges on the surfaces on which the spiders sit, creating enough force to lift them into the air. And spiders can increase those forces by climbing onto twigs, leaves, or blades of grass. Plants, being earthed, have the same negative charge as the ground that they grow upon, but they protrude into the positively charged air. This creates substantial electric fields between the air around them and the tips of their leaves and branches—and the spiders ballooning from those tips.

[fuckyeahfluiddynamics]

Paris 2024: Clearing the Air

A quartet of mushroom-shaped structures tower nearly 6 meters above the Olympic Village. Known as Aerophiltres, these devices filter particulates out of the air to provide cleaner air for the Village, despite its proximity to major roadways.  (Image credit: SOLIDEO/C. Badet; via DirectIndustry) Catch our past and ongoing Olympic coverage here. Read the full article

[fuckyeahfluiddynamics]

A Plasma Arc Lights

[fuckyeahfluiddynamics]

Turbulence in Accretion Disks

Accretion disks form everywhere, from around young, planet-building stars to massive black holes. As matter circles in the disk, it slowly loses angular momentum and falls inward toward the central gravitational body. But the details of this process have long vexed astronomers. (Image credit: NASA; research credit: M. Vernet et al.; via Physics World)

[fuckyeahfluiddynamics]

Water Builds Static Charge

The ancient Greeks first recognized static electricity, but the mechanisms behind it remain somewhat mysterious. In particular, it's unclear how two pieces of the same material can build a charge between them simply by touching. Yet we regularly see examples of this when volcanic ash creates enough charge to discharge lightning. (Image credit: volcano - M. Szeglat, experiment - G. Grosjean and S. Waitukaitis; research credit: G. Grosjean and S. Waitukaitis; via APS Physics)

[fuckyeahfluiddynamics]

Driven From Equilibrium

With the right application of force, liquids can take on shapes that defy our intuition. Here researchers sandwiched two immiscible oils between glass slides and applied an electric field. (Image, video, and research credit: G. Raju et al.; via Physics World) Read the full article