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Intelligent Designs in Nature Make Engineers Envious

131058_023_MW_Amy_Lang.jpgWe've reported numerous times about the vibrant field of biomimetics: the science of imitating nature. There are whole departments at universities dedicated to this. There are journals like Bioinspiration and Biomimetics, the Journal of Biomimetics, Biomaterials, and Tissue Engineering, and Frontiers in Bioengineering and Biotechnology that regularly report on it. Entrepreneurs have started companies to build products mimicking nature. Biomimetics is on a roll. Here are a few of scientists' latest attempts to copy nature's designs. They wouldn't try so hard if the designs weren't intelligent.

Flight on the Small Scale

A news item from the University of Alabama shows Dr. Amy Lang studiously gazing at a Monarch butterfly on the wing. She has reason to stay focused. She just got a $280,000 grant from the National Science Foundation to study the scales on butterfly wings to find ways to improve flight aerodynamics for MAVs (micro area vehicles).

Butterflies don't require the scales to fly, but Dr. Lang knows they help the insects fly better. "The butterfly scales are beautifully arranged on the wing, and how the scales are arranged is where the aerodynamic benefit comes in," she says. This "unique micro pattern ... reduces drag and likely increases thrust and lift during flapping and glided flight." When the scales are removed, the butterfly has to flap its wings 10 percent more to maintain the same flight.

Scales.jpgIf you've seen Metamorphosis: The Beauty and Design of Butterflies you may recall the striking electron micrographs of the tiny scales, each less than a tenth of a millimeter in width, arranged like shingles on a roof. According to Dr. Lang, there's a reason: "the scales stick up slightly, trapping a ball of air under the scale and allowing air to flow smoothly over it." Her team wants to understand the physics behind this design before trying to model it on artificial flyers.

The article assumes butterflies happened upon these "evolutionary adaptations" by blind, unguided processes: "The scales covering butterfly and moth wings represent about 190 million years of natural selection for insect flight efficiency." Metamorphosis refutes that notion, but what matters in the story is not evolution, but design -- here is a natural design that the NSF feels is worth at least $280,000 to try to imitate. (Dr. Lang also "works with shark scales" in her "bio-designed engineering" lab.)

It's a Bird; It's a Plane; It's Robo Raven

You met nano-hummingbird in Illustra's film Flight: The Genius of Birds. Now here's Robo Raven, a flying drone built at the University of Maryland -- the first Micro Air Vehicle (MAV) using flapping flight. We've noted this briefly before. A video clip shows how Robo Raven III uses sunlight from solar panels built into its wings to charge batteries.

Nature, as usual, does it better. The Robo Raven III can only gather about 30 watts -- an order of magnitude too low to stay aloft indefinitely, IEEE Spectrum says, pointing out that real ravens get "crazy high power density" from meat. On his blog, Professor S. K. Gupta of the UMass design team compares performance between the two, noting that his invention also mimics another natural technology -- solar energy collection by plants:

However, nature has a significant edge over engineered system in other areas. For example, one gram of meat stores 20 times more energy than one gram of the current battery technology. So in terms of the energy density, we engineers have a lot of catching up to do. In nature, solar energy collection devices (e.g., trees) are not on-board ravens. Hence, ravens ultimately utilize a large collection area to gather energy into highly a dense storage source (e.g., meat), giving them a much longer range and better endurance than Robo Raven III. (Emphasis added.)

While Gupta notes that direct solar energy conversion to mechanical energy would be about an order of magnitude more efficient than an animal's metabolic pathway, "We still need to make significant improvements in solar cell efficiency and battery energy density to replicate the endurance of real ravens in Robo Raven III," he confesses. Real ravens also use that metabolism to perform many functions besides flapping flight -- including reproduction, navigation, and the operation of multiple senses. (Living birds can also fly at night.)

Short Takes

  • Solar power: "Inspired by nature: To maximise the efficiency of solar cells of the future, physicists are taking a leaf out of nature's book" (Cavendish Laboratory, University of Cambridge).
  • Robotics: "Amber 2 robot walks with a human gait." Why is that good? "People are able to walk so smoothly because of the seamless interaction between the muscles, bone, ligaments, etc. in the legs, ankles and feet ... Getting a robot to walk like us means not just building legs, ankles or feet like ours, it means programming them all to work together in way that is graceful when the robot walks, and that appears to be where the Amber 2 team is headed" (PhysOrg reporting on work at Texas A&M).
  • Sonar: An engineer was watching a nature show and wondered why dolphins blew bubbles to trap fish, when it would seemingly mess up their sonar signals. He found that the dolphins use two click frequencies that allow them to distinguish between the bubbles and fish. This "inspired the development of a cheap, coin-sized radar gadget that can sense hidden electronics" (New Scientist, reporting on work at University of Southampton).

Does Darwin-Talk Add Value?

Occasionally, news stories like these attribute the designs in question to natural selection. "Through billions of years of evolution, life on Earth has found intricate solutions to many of the problems scientists are currently grappling with," the item from Cambridge says. But then, most of the story marvels at the intricate design that blind nature supposedly arrived at.

Biology has evolved phenomenally subtle systems to funnel light energy around and channel it to the right places. It has also become incredibly good at building tiny devices that work with high efficiency, and at replicating them millions of times.

Similarly, New Scientist ends its biodesign story with: "Evolution has once again sparked ideas for remarkable innovation."
The Darwin language gets to be as annoying as those pop-up ads on the Internet that have nothing to do with the story. The focus is on design -- "intricate solutions" so good, they occupy the best minds in the world's finest academic institutions; designs so attractive, they are worth six-figure government grants to imitate.

You wouldn't want to insult bioengineers with the suggestion they are mimicking blind, unguided processes in their work. No, from our uniform experience, a good design comes from a good mind.

Photo credit: University of Alabama.