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Wednesday, December 7, 2016

Obi, the Parrotlet, Laser Goggles, and Air Vortices

         A parrotlet named Obi has his own set of custom-made safety goggles (made from human-sized ones) to protect his eyes when he flies through a laser sheet, as he has been trained to do. Researchers at Stanford University are studying how air moves in the wake of Obi's flight.



  

     This 46-second video of Obi's flight shows the vortices swirling around the bird's flightpath, thanks to the lasers he is flying through.




        Researchers at Stanford University are studying how the air moves in the wake of a bird's flight. Thank to Obi, along with graduate students Eric Gutierrez and Diana Chin, and mechanical engineer David Letink, we now know that there may be some faults in many flight models.





       "The goal of our study was to compare very commonly used models in the literature to figure out how much lift a bird, or other flying animal, generates based off its wake," Chin said. "What we found was that all three models we tried out were very inaccurate because they make assumptions that aren't necessarily true."



     To test the models, the team trained Obi, a parrotlet or pocket parrot, to wear the goggles and fly from one perch to another. Then a laser sheet was seeded with non-toxic, aerosol-sized particles. As Obi flew through this laser sheet, the disturbed particles swirled into vortices left in his wake.




     The tests showed something unexpected. Computer models predicted that once the whirling air patterns or vortices were created by a bird's wings, they would remain relatively stable in the air. But the patterns Obi traced began to disintegrate after the bird flapped its wings just a few times.




      "We were surprised to find the vortices that are usually drawn in papers and text books as beautiful doughnut rings turned out to break up dramatically after two to three wing beats," Lentink said. He explained that this meant the models, which are widely used in animal flight studies to calculate an animal's lift based on the wake it produced, were likely inaccurate.




      "Whereas vortex breakup happens far away behind the aircraft (more than a thousand meters) in birds, it can happen very close to the bird, within two or three wingbeats , and it is much more violent," said Letink.





      The team also found that the models they tested did not accurately predict the lift generated by Obi's wings. This research joins other studies conducted by the lab on many different animals, including different bird species, bats, and insects. The team hopes the findings can be used to help develop flying robots or drones that flap wings, rather than rely on rotors.

Wonder if Obi knows Obi-wan Kenobi,
Steph






58 comments:

  1. Obi's goggles and gestalt reminded me of this.

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    1. "Junior Birdman" song is the best! And, this is a particularly riveting version.

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    2. Well then, how about this particularly ribbiting version of this junior frogman song?

      FrogLego

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    3. All toad, quite ribbiting, Lego!

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    4. I wonder whether Donald and Mitt were dining on Pepe the Frog's legs that night at Jean Georges?

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    5. I had no idea about white supremacist hate and Pepe. . .

      Besides, I thought DT was supposed to be draining the swamp, not eating from it.

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    6. I think Stephen Colbert had the same comment (about draining the swamp).

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  2. So interesting. Thank you, Obi and Steph!

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    1. Thanks, Joanne. I wonder how he became Obi.

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    2. We crossword fans think Obi should take a bow....

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    3. jan, have you known about Obi before?

      As to the meaning of OBI:

      Obi is an African name which means "heart"

      Obi is the karate or kimono belt

      Okwu Nkasi Obi means words of comfort

      Obi means "soul" in Swahili

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    4. The only obi I've known is the kimono sash, which appears frequently in crosswords. The only Swahili I remember seeing in Will's puzzles are Uhura and Hakuna Matata.

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    5. Yes, our Japanese students gifted us with many kimonos with intricately-stitched obis.

      "Heart" and "soul" are great meanings for little Obi.

      The image of the goggles on Obi pushed the story to the forefront because, well, how can you resist that cute photo?

      Wonder if we could get some cute goggles to go on fossil animals ;-).

      Whoa. -4 degrees F here right now. Brrrr.

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  3. Replies
    1. Those goggles also remind me of the frosted "contact lenses" that Charlie Walcott had his pigeons wear. They mostly didn't interfere with navigation unless the little Helmholtz coils they also wore were energized. You can find your way home without visual cues or magnetic cues, but not without both.

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    2. The cryptochrome protein in the eye is especially interesting.

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  4. Replies

    1. jan, of course, and they all have homes in the Simply Irresistible Little Town of SILT, COLORADO..

      No silt! I kid you not. . .


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  5. Today's Earth Science Picture of the Day (EPOD) is of a contrail over Paris showing the phenomenon clearly.
    Timely, WW

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    1. Wow, that is timely, Mendo Jim. Happy to know about EPOD. It looks like a fun way to start the day. . .

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  6. Replies
    1. Yes, but would this feathered dinosaur, nicknamed Amber, fly like Obi with goggles on through lasers?

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    2. She could wave stalks of wheat while flying on the lasers >>> "For Amber Waves of Grain. . ."

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    3. So the dinosaurs are less like "Jurassic Park" and more like Big Bird of Sesame Street? Thankfully they're not like Barney....

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    4. eco, yes some feathered dinosaurs may have had the goody Big Bird look, although many also were quite ferocious.

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  7. OK, a little bigger bird than a parrotlet: I liked Helen Macdonald's H is for Hawk, which I read last year, but much more fun, with less privilege and neurosis, is the new documentary, The Eagle Huntress, about a 13-year old Kazakh Mongolian girl who wants to be a surgeon but first wants to train an eagle to hunt.

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    1. Striking image. Sounds like a great read.

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    2. Sorry to have been unclear, The Eagle Huntress is a new documentary movie, not a book. And I don't really mean to knock H is for Hawk much; it was a very interesting book, and I feel I connected much more with The Eagle Huntress having read it.

      We once went for a bird-watching walk in the Bay Area with a good friend of my son. He's an avid birder, whom I've mentioned here previously. My wife asked him how he got into birding, and he said that he'd become fascinated with their individual personalities, that each one to him was as different from others of the same species as people are.

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    3. I agree birds will have different personalities, at least in my casual and very unscientific observations.

      In the Bay Area we are fortunate to have quite a few red-tailed hawks, and while most are relatively shy, there was one who seemed to enjoy swooping down Shattuck Avenue in our "Gourmet Ghetto" (Alice Water's Chez Panisse and others) literally slaloming between the heads of the many pedestrians. He would then land on a tree in the Bank of America parking lot, and do the whole thing over. I say "he" not with knowledge, but under the assumption that only young males are that crazy.

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    4. There's one restaurant on the edge of the Great Swamp National Wildlife Refuge, where I bike, and there's always a bunch of turkey vultures and black vultures skulking around on the roof and near the parking lot. I assume they're attracted by rodents that are attracted by what they find in the Dumpster out back. But, if Chez Panisse was nearby, I'm sure they'd all hang out there instead.

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    5. Small point: I don't know about black vultures, but turkey vultures are not very good hunters. They fulfill a very important niche by eating carrion. I suspect they are waiting for food scraps, not mice.

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    6. eco, what's the story on the blue house in your thumbnail?

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    7. It's not a house, it's an old industrial warehouse that was occupied haphazardly by artists, much like the Ghost Ship of recent tragedy.

      The pictured structure was purchased by a non-profit housing organization, which hired me to convert it into legal and safe artists' housing, including a performance theater. Sadly the project was finishing construction when the not-so-great-depression hit in 2008, and no one could get financing to purchase units.

      I've been involved in helping other artist groups try to legalize their spaces, sometimes successfully, more often not - money is the big barrier.

      So I put up the image as my small tribute to the artistic community in Oakland. I knew one of the victims, and another was a tenant of one of my clients.

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    8. eco, I am sorry you were touched so personally by the Ghost Ship tragedy. Your small tribute is quite thoughtful and beautiful. The blue/indigo is striking.

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    9. Thanks. It is extra sad because this could easily have been prevented, but the societal mechanisms just aren't there.

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  8. We have a "Dames and Docs" get-together once a month. This documentary sounds like a great addition to our list. Looks like it is still being shown in one theater here.

    Interesting about your birder friend. I guess that makes sense as dogs and cats have different personalities; why not birds? It seems harder to get to know them with all that flying around.

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    1. At the bottom it notes that the organizers of this "publication" are really just scam artists, signing you up and then requiring fees to publish your paper (and the fine print in their contract says you can't publish anywhere else). They also run a series of conferences that also look like total scams, judging from the atomic physics one he links to. Their "descriptions" look like a 14 year old did a cut and paste from Wikipedia.

      Reminds me of those annoying Who's Who scams, or the opportunities to have an on-line "radio program" if you pay a fee or bring in your own advertisers. I get regular invitations to speak at similar conferences (usually in Vegas or China, hmm), fortunately the trash button is always near.

      Fake publications, fake conferences, fake news, fake candidates. The world's faked up!

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    2. So true. Did you notice the link in the article is messed up and says "Take me of your f**king mailing list? Take this link and (sh)of(e) it?!

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    3. I didn't notice, but I'm reasonably forgiving to those who make typo mistakes, like leaving of a letter.

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    4. Yes, I like to comfort someone with "there, they're, their." You're welcome.

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  10. The kindergartners' equivalent of Don't eat your data! {SMH daily these days}

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  11. Happy ending: one way to get your kids to eat vegetables: Asparagus Pee .

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    1. That, and corn poops. I once heard someone say he likes Mountain Dew because it doesn't change color when you drink it.

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    2. Whatever floats your boat >>> beets me ;-).

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  12. New post on "Thinner Crust: Not Just for Pizza Anymore -- Oceanic Crust has Thinned Since Pangaean Jurassic Time" is now up.

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