close
    • chevron_right

      The physics of how gentoo penguins can swim speedily underwater

      news.movim.eu / ArsTechnica · Thursday, 6 July, 2023 - 22:33 · 1 minute

    A gentoo penguin swimming

    Enlarge / Gentoo penguins are the world's fastest swimming birds, thanks to the unique shape and structure of their wings. (credit: Priya Venkatesh/CC BY-SA 3.0 )

    Gentoo penguins are the world's fastest swimming birds, clocking in at maximum underwater speeds of up to 36 km/h (about 22 mph). That's because their wings have evolved into flippers ideal for moving through water (albeit pretty much useless for flying in the air). Physicists have now used computational modeling of the hydrodynamics of penguin wings to glean additional insight into the forces and flows that those wings create underwater. They concluded that the penguin's ability to change the angle of its wings while swimming is the most important variable for generating thrust, according to a recent paper published in the journal Physics of Fluids.

    “Penguins’ superior swimming ability to start/brake, accelerate/decelerate, and turn swiftly is due to their freely waving wings," said co-author Prasert Prapamonthon of King Mongkut‘s Institute of Technology Ladkrabang in Bangkok, Thailand. "They allow penguins to propel and maneuver in the water and maintain balance on land. Our research team is always curious about sophisticated creatures in nature that would be beneficial to mankind.”

    Scientists have long been interested in the study of aquatic animals. Such research could lead to new designs that reduce drag on aircraft or helicopters. Or it can help build more efficient bio-inspired robots for exploring and monitoring underwater environments—such as RoboKrill , a small, one-legged, 3D-printed robot designed to mimic the leg movement of krill so it can move smoothly in underwater environments.

    Read 9 remaining paragraphs | Comments

    • chevron_right

      These juvenile snapping shrimp have the fastest claws in the sea

      news.movim.eu / ArsTechnica · Tuesday, 7 March, 2023 - 21:36 · 1 minute

    Juvenile snapping shrimp now hold the acceleration record for a repeatable body movement underwater. They can snap their claws at accelerations on par with a bullet shot from a gun.

    Juvenile snapping shrimp now hold the acceleration record for a repeatable body movement underwater. They can snap their claws at accelerations on par with a bullet shot from a gun. (credit: Harrison and Patek, 2023)

    The snapping shrimp , aka the pistol shrimp, is one of the loudest creatures in the ocean, thanks to the snaps produced by its whip-fast claws. And juvenile snapping shrimp are even faster than their fully grown elders, according to a recent paper published in the Journal of Experimental Biology. Juvenile claws accelerate as fast as a bullet shot from a gun when they snap, essentially setting a new acceleration record for a repeated movement performed underwater.

    As we've reported previously, the source of that loud snap is an impressive set of asymmetrically sized claws; the larger of the two produces the snap. Each snap also produces a powerful shockwave that can stun or even kill a small fish. That shockwave produces collapsing bubbles that emit a barely visible flash of light—a rare natural example of sonoluminescence .

    Scientists believe that the snapping is used for communication, as well as for hunting. A shrimp on the prowl will hide in a burrow or similar obscured spot, extending antennae to detect any passing fish. When it does, the shrimp emerges from its hiding place, pulls back its claw, and lets loose with a powerful snap, producing the deadly shockwave. It can then pull the stunned prey back into the burrow to feed.

    Read 9 remaining paragraphs | Comments

    • chevron_right

      Watch these glassy-winged sharpshooters fling pee bubbles with anal catapult

      news.movim.eu / ArsTechnica · Tuesday, 28 February, 2023 - 19:23 · 1 minute

    Insects called glassy-wing sharpshooters have an "anal stylus" capable of flicking pee droplets at very high speeds.

    The glassy-winged sharpshooter drinks huge amounts of water and thus pees frequently, expelling as much as 300 times its own body weight in urine every day. Rather than producing a steady stream of urine, sharpshooters form drops of urine at the anus and then catapult those drops away from their bodies at remarkable speeds, boasting accelerations 10 times faster than a Lamborghini. Georgia Tech scientists have determined that the insect uses this unusual "superpropulsion" mechanism to conserve energy, according to a new paper published in the journal Nature Communications.

    A type of leafhopper , the glassy-winged sharpshooter ( Homalodisca vitripennis) is technically an agricultural pest, the bane of California winemakers in particular since the 1990s. It feeds on many plant species (including grapes), piercing a plant's xylem (which transports water from the roots to stems and leaves) with its needle-like mouth to suck out the sap. The insects consume a lot of sap, and their frequent urination consumes a lot of energy in turn, because of their small size and the sap's viscosity and negative surface tension (it naturally gets sucked inward). But the sap is about 95 percent water, so there's not much nutritional content to fuel all that peeing.

    “If you were only drinking diet lemonade, and that was your entire diet, then you really wouldn’t want to waste energy in any part of your biological process,” co-author Saad Bhamla of Georgia Tech told New Scientist . “That’s sort of how it is for this tiny organism.”

    Read 6 remaining paragraphs | Comments

    • chevron_right

      Sauropods had soft foot pads to help support their massive weight

      news.movim.eu / ArsTechnica · Thursday, 11 August, 2022 - 20:48 · 1 minute

    A 3D paleoreconstruction of a sauropod dinosaur has revealed that the hind feet had a soft tissue pad beneath the "heel," cushioning the foot to absorb the animals immense weight.

    Enlarge / A 3D paleoreconstruction of a sauropod dinosaur has revealed that the hind feet had a soft tissue pad beneath the "heel," cushioning the foot to absorb the animals immense weight. (credit: Andreas Jannel)

    Ask people to think of a dinosaur, and they'll likely name Tyrannosaurus Rex , the carnivorous antagonist prominently featured in the Jurassic Park and Jurassic World film franchises. But an equally well-known dinosaur clade are the herbivorous sauropods , which include Brachiosaurus, Diplodocus, Apatosaurus , Argentinosaurus , and Brontosaurus . Australian paleontologists have digitally reconstructed these plant-munching giants to glean insight into how their feet managed to support their enormous weight, according to a new paper published in the journal Science Advances.

    "We've finally confirmed a long-suspected idea and we provide, for the first time, biomechanical evidence that a soft tissue pad—particularly in their back feet—would have played a crucial role in reducing locomotor pressures and bone stresses," said co-author Andreas Jannel , who worked on the project while completing doctoral studies at the University of Queensland. "It is mind-blowing to imagine that these giant creatures could have been able to support their own weight on land."

    Sauropods (clade name: Sauropoda, or "lizard feet") had long-necked, long-tailed bodies that made them the lengthiest animals to have roamed the Earth. They had thick and powerful hind legs, club-like feet with five toes, and more slender forearms. It's rare to find complete Sauropod fossils, and even those that are mostly complete still lack the heads, tail tips, and limbs. Scientists have nonetheless managed to learn a great deal about them, and digital reconstruction is proving to be a valuable new tool in advancing our knowledge even further.

    Read 11 remaining paragraphs | Comments

    • chevron_right

      Scientists built a tiny robot to mimic the mantis shrimp’s knock-out punch

      Jennifer Ouellette · news.movim.eu / ArsTechnica · Monday, 30 August, 2021 - 22:05 · 1 minute

    An interdisciplinary team of roboticists, engineers and biologists modeled the mechanics of the mantis shrimp’s punch and built a robot that mimics the movement.

    Enlarge / An interdisciplinary team of roboticists, engineers and biologists modeled the mechanics of the mantis shrimp’s punch and built a robot that mimics the movement. (credit: Second Bay Studios and Roy Caldwell/Harvard SEAS)

    The mantis shrimp boasts one of the most powerful, ultrafast punches in nature—it's on par with the force generated by a .22 caliber bullet. This makes the creature an attractive object of study for scientists eager to learn more about the relevant biomechanics. Among other uses, it could lead to small robots capable of equally fast, powerful movements. Now a team of Harvard University researchers have come up with a new biomechanical model for the mantis shrimp's mighty appendage, and they built a tiny robot to mimic that movement, according to a recent paper published in the Proceedings of the National Academy of Sciences (PNAS).

    “We are fascinated by so many remarkable behaviors we see in nature, in particular when these behaviors meet or exceed what can be achieved by human-made devices,” said senior author Robert Wood, a roboticist at Harvard University's John A. Paulson School of Engineering and Applied Sciences (SEAS). “The speed and force of mantis shrimp strikes, for example, are a consequence of a complex underlying mechanism. By constructing a robotic model of a mantis shrimp striking appendage, we are able to study these mechanisms in unprecedented detail.”

    Wood's research group made headlines several years ago when they constructed RoboBee , a tiny robot capable of partially untethered flight. The ultimate goal of that initiative is to build a swarm of tiny interconnected robots capable of sustained untethered flight—a significant technological challenge, given the insect-sized scale, which changes the various forces at play. In 2019, Wood's group announced their achievement of the lightest insect-scale robot so far to have achieved sustained, untethered flight—an improved version called the RoboBee X-Wing. (Kenny Breuer, writing in Nature, described it as a "a tour de force of system design and engineering.")

    Read 11 remaining paragraphs | Comments

    index?i=gLH8YNAK1Ms:gNcyer1s3ag:V_sGLiPBpWUindex?i=gLH8YNAK1Ms:gNcyer1s3ag:F7zBnMyn0Loindex?d=qj6IDK7rITsindex?d=yIl2AUoC8zA