http://ngm.nationalgeographic.com/2008/04/biomimetics/tom-mueller-text

Biomimetics

Biomimetics: Design by Nature
What has fins like a whale, skin like a lizard, and eyes like a moth? The future of engineering.

By Tom Mueller

Photograph by Robert Clark

Biomimetics: Design by Nature

What has fins like a whale, skin like a lizard, and eyes like a moth? The future of engineering.

By Tom Mueller

One cloudless midsummer day in February, Andrew Parker, an
evolutionary biologist, knelt in the baking red sand of the Australian
outback just south of Alice Springs and eased the right hind leg of a
thorny devil into a dish of water. The maneuver was not as risky as it
sounds: Though covered with sharp spines, the lizard stood only about
an inch high at the shoulder, and it looked up at Parker
apprehensively, like a baby dinosaur that had lost its mother. It
seemed too cute for its harsh surroundings, home to an alarmingly high
percentage of the world's most venomous snakes, including the inland
taipan, which can kill a hundred people with an ounce of its venom, and
the desert death adder, whose name pretty well says it all. Fierce too
is the landscape itself, where the wind hissing through the mulga trees
feels like a blow dryer on max, and the sun seems three times its size
in temperate climes. Constant reminders that here, in the driest part
of the world's driest inhabited continent, you'd better have a good
plan for where your next drink is coming from.

This the thorny devil knows, with an elegance and certainty that
fascinated Parker beyond all thought of snakebite or sunstroke. "Look,
look!" he exclaimed. "Its back is completely drenched!" Sure enough,
after 30 seconds, water from the dish had wicked up the lizard's leg
and was glistening all over its prickly hide. In a few seconds more the
water reached its mouth, and the lizard began to smack its jaws with
evident satisfaction. It was, in essence, drinking through its foot.
Given more time, the thorny devil can perform this same conjuring trick
on a patch of damp sand—a vital competitive advantage in the desert.
Parker had come here to discover precisely how it does this, not from
purely biological interest, but with a concrete purpose in mind: to
make a thorny-devil-inspired device that will help people collect
lifesaving water in the desert.

A slender English academic with wavy, honey-blond hair beneath a
wide-brimmed sun hat, Parker busied himself with eyedroppers, misters,
and various colored powders, the better to understand the thorny
devil's water-collecting alchemy. Now and then he made soft, bell-like,
English-academic sounds of surprise and delight. "The water's spreading
out incredibly fast!" he said, as drops from his eyedropper fell onto
the lizard's back and vanished, like magic. "Its skin is far more
hydrophobic than I thought. There may well be hidden capillaries,
channeling the water into the mouth." After completing his last
experiment, we gathered up his equipment and walked back to our Land
Cruiser. The lizard watched us leave with a faint look of bereavement.
"Seeing the devil in its natural environment was crucial to
understanding the nature of its adaptations—the texture of the sand,
the amount of shade, the quality of the light," Parker said as we drove
back to camp. "We've done the macro work. Now I'm ready to look at the
microstructure of its skin."

A research fellow at the Natural History Museum in London and at the
University of Sydney, Parker is a leading proponent of
biomimetics—applying designs from nature to solve problems in
engineering, materials science, medicine, and other fields. He has
investigated iridescence in butterflies and beetles and antireflective
coatings in moth eyes—studies that have led to brighter screens for
cellular phones and an anticounterfeiting technique so secret he can't
say which company is behind it. He is working with Procter & Gamble
and Yves Saint Laurent to make cosmetics that mimic the natural sheen
of diatoms, and with the British Ministry of Defense to emulate their
water-repellent properties. He even draws inspiration from nature's
past: On the eye of a 45-million-year-old fly trapped in amber he saw
in a museum in Warsaw, Poland, he noticed microscopic corrugations that
reduced light reflection. They are now being built into solar panels.

Parker's work is only a small part of an increasingly vigorous,
global biomimetics movement. Engineers in Bath, England, and West
Chester, Pennsylvania, are pondering the bumps on the leading edges of
humpback whale flukes to learn how to make airplane wings for more
agile flight. In Berlin, Germany, the fingerlike primary feathers of
raptors are inspiring engineers to develop wings that change shape
aloft to reduce drag and increase fuel efficiency. Architects in
Zimbabwe are studying how termites regulate temperature, humidity, and
airflow in their mounds in order to build more comfortable buildings,
while Japanese medical researchers are reducing the pain of an
injection by using hypodermic needles edged with tiny serrations, like
those on a mosquito's proboscis, minimizing nerve stimulation.

"Biomimetics brings in a whole different set of tools and ideas you
wouldn't otherwise have," says materials scientist Michael Rubner of
MIT, where biomimetics has entered the curriculum. "It's now built into
our group culture."

Shortly after our trip to the Australian desert, I met up with
Andrew Parker again, in London, to watch the next phase of his research
into the thorny devil. Walking from the Natural History Museum's
entrance to his laboratory on the sixth floor, we traversed
warehouse-size halls filled with preserved organisms of the most
exuberant variety. In one room were waist-high alcohol jars of
grimacing sea otters, pythons, spiny echidnas, and wallabies, and one
65-foot-long case containing a giant squid. Other rooms held displays
of gaudy hummingbirds, over-the-top toucans and majestic bowerbirds,
and shelf after shelf filled with beetles as bright as gemstones:
emerald-green scarabs, sapphire-blue Cyphogastras, and opalescent weevils.

To Parker this was not a mere collection of specimens, but "a
treasure-trove of brilliant design." Every species, even those that
have gone extinct, is a success story, optimized by millions of years
of natural selection. Why not learn from what evolution has wrought? As
we walked, Parker explained how the metallic sheen and dazzling colors
of tropical birds and beetles derive not from pigments, but from
optical features: neatly spaced microstructures that reflect specific
wavelengths of light. Such structural color, fade-proof and more
brilliant than pigment, is of great interest to people who manufacture
paint, cosmetics, and those little holograms on credit cards. Toucan
bills are a model of lightweight strength (they can crack nuts, yet are
light enough not to seriously impede the bird's flight), while hedgehog
spines and porcupine quills are marvels of structural economy and
resilience. Spider silk is five times stronger by weight and vastly
more ductile than high-grade steel. Insects offer an embarrassment of
design riches. Glowworms produce a cool light with almost zero energy
loss (a normal incandescent bulb wastes 98 percent of its energy as
heat), and bombardier beetles have a high-efficiency combustion chamber
in their posterior that shoots boiling-hot chemicals at would-be
predators. The Melanophila beetle, which lays its eggs in
freshly burned wood, has evolved a structure that can detect the
precise infrared radiation produced by a forest fire, allowing it to
sense a blaze a hundred kilometers away. This talent is currently being
explored by the United States Air Force.

"I could look through here and find 50 biomimetics projects in half
an hour," Parker said. "I try not to walk here in the evening, because
I end up getting carried away and working until midnight."

In one such late-night creative burst eight years ago, Parker
decided to investigate the water-gathering skills of a desert beetle by
building an enormous sand dune in his laboratory. This tenebrionid
beetle flourishes in the Namib Desert in southwestern Africa, one of
the world's hottest, driest environments. The beetle drinks by
harvesting morning fogs, facing into the wind and hoisting its behind,
where hydrophilic bumps capture the fog and cause it to coalesce into
larger droplets, which then roll down the waxy, hydrophobic troughs
between the bumps, reaching the beetle's mouth. Parker imported several
dozen beetles from Namibia, which promptly scampered all over the lab
when he opened the box, but eventually settled contentedly on the dune.
There, using a hair dryer and various misters and spray bottles, Parker
simulated the conditions in the Namib Desert well enough to understand
the beetle's mechanism. He then replicated it on a microscope slide,
using tiny glass beads for the bumps and wax for the troughs.

For all nature's sophistication, many of its clever devices are made
from simple materials like keratin, calcium carbonate, and silica,
which nature manipulates into structures of fantastic complexity,
strength, and toughness. The abalone, for example, makes its shell out
of calcium carbonate, the same stuff as soft chalk. Yet by coaxing this
material into walls of staggered, nanoscale bricks through a subtle
play of proteins, it creates an armor as tough as Kevlar —3,000 times
harder than chalk. Understanding the microscale and nanoscale
structures responsible for a living material's exceptional properties
is critical to re-creating it synthetically. So today Andrew Parker had
arranged to view the skin of a thorny devil museum specimen under a
scanning electron microscope, hoping to find the hidden structures that
allow it to absorb and channel water so effectively.

With a microscopist at the helm, we soared over the surface of the
thorny devil's skin like a deep-space probe orbiting a distant planet,
dipping down now and then at Parker's request to explore some curious
feature of the terrain. There seemed to be little of interest in the
Matterhornlike macrostructure of an individual thorn, though Parker
speculated that it might wick away heat from the lizard's body or
perhaps help capture the morning dew. Halfway down the thorn, however,
he noticed a series of nodules set in rows, which seemed to grade down
to a larger water-collection structure. Finally we dove into a crevasse
at the base of the thorn and encountered a honeycomb-like field of
indentations, each 25 microns across.

"Ah-ha!" Parker exclaimed, like Sherlock Holmes alighting upon a
clue. "This is clearly a superhydrophobic surface for channeling water
between the scales." A subsequent examination of the thorny devil's
skin with an instrument called a micro-CT scanner confirmed his theory,
revealing tiny capillaries between the scales evidently designed to
guide water toward the lizard's mouth. "I think we've pretty well
cracked the thorny devil structure," he said. "We're ready to make a
prototype."

Enter the engineers. As the next phase in his quest to create a
water-collection device inspired by the lizard, Parker sent his
observations and experimental results to Michael Rubner and his MIT
colleague Robert Cohen, a chemical engineer with whom he has worked on
several biomimetics projects in the past. Rubner and Cohen are neatly
groomed gentlemen who speak in clipped phrases and look frequently at
their watches. While Parker likes to explain his work via a stroll
through a botanic garden or by pulling out drawerfuls of bright beetles
in a museum, they are more likely to draw a tidy graph of force over
time, or flip through a PowerPoint presentation on their laptop. But a
pooling of biological insight and engineering pragmatism is vital to
success in biomimetics, and in the case of Parker, Cohen, and Rubner,
it has led to several promising applications inspired by the Namib
beetle and other insects. Using a robotic arm that, in a predetermined
sequence, dips slides into a series of nanoparticle suspensions and
other exotic ingredients, they have assembled materials layer by layer
that have the same special properties as the organisms. Soon they hope
to apply the method to create a synthetic surface inspired by thorny
devil skin.

Though impressed by biological structures, Cohen and Rubner consider
nature merely a starting point for innovation. "You don't have to
reproduce a lizard skin to make a watercollection device, or a moth eye
to make an antireflective coating," Cohen says. "The natural structure
provides a clue to what is useful in a mechanism. But maybe you can do
it better." Lessons from the thorny devil may enhance the
water-collection technology they have developed based on the
microstructure of the Namib beetle, which they're working to make into
water-harvesting materials, graffiti-proof paints, and
self-decontaminating surfaces for kitchens and hospitals. Or the work
may take them in entirely new directions. Ultimately they consider a
biomimetics project a success only if it has the potential to make a
useful tool for people. "Looking at pretty structures in nature is not
sufficient," says Cohen. "What I want to know is, Can we actually
transform these structures into an embodiment with true utility in the
real world?"

Which, of course, is the tricky bit. Potentially one of the most
useful embodiments of natural design is the bio-inspired robot, which
could be deployed in places where people would be too conspicuous,
bored to tears, or killed. But such robots are notoriously difficult to
build. Ronald Fearing, a professor of electrical engineering at the
University of California, Berkeley, has taken on one of the biggest
challenges of all: to create a miniature robotic fly that is swift,
small, and maneuverable enough for use in surveillance or
search-and-rescue operations.

If a blowfly had buzzed into Fearing's office when we first sat down
on a warm March afternoon, the windows flung wide to the garden-like
Berkeley campus, I would have swatted it away without a second thought.
By the time Fearing finished explaining why he had chosen it as the
model for his miniature aircraft, I would have fallen on bended knee in
admiration. With wings beating 150 times per second, it hovers, soars,
and dives with uncanny agility. From straight-line flight it can turn
90 degrees in under 50 milliseconds —a maneuver that would rip the
Stealth fighter to shreds.

The key to making his micromechanical flying insect (MFI) work,
Fearing said, isn't to attempt to copy the fly, but to isolate the
structures crucial to its feats of flying, while keeping a sharp eye
out for simpler—and perhaps better—ways to perform its highly complex
operations. "The fly's wing is driven by 20 muscles, some of which only
fire every fifth wing beat, and all you can do is wonder, What on Earth
just happened there?" says Fearing. "Some things are just too
mysterious and complicated to be able to replicate."

After CalTech neurobiologist Michael Dickinson used foot-long
plastic wings flapping in two tons of mineral oil to demonstrate how
the fly's U-shaped beat kept it aloft, Fearing whittled the complexity
of the wing joint down to something he could manufacture. What he came
up with resembles a tiny automobile differential; though lacking the
fly's mystical 20-muscle poetry, it can still bang out U-shaped beats
at high speed. To drive the wing, he needed piezoelectric actuators,
which at high frequencies can generate more power than fly muscle can.
Yet when he asked machinists to manufacture a ten-milligram actuator,
he got blank stares. "People told me, 'Holy cow! I can do a ten-gram
actuator,' which was bigger than our whole fly."

So Fearing made his own, one of which he held up with tweezers for
me to see, a gossamer wand some 11 millimeters long and not much
thicker than a cat's whisker. Fearing has been forced to manufacture
many of the other minute components of his fly in the same way, using a
micromachining laser and a rapid prototyping system that allows him to
design his minuscule parts in a computer, automatically cut and cure
them overnight, and assemble them by hand the next day under a
microscope.

With the microlaser he cuts the fly's wings out of a two-micron
polyester sheet so delicate that it crumples if you breathe on it and
must be reinforced with carbon-fiber spars. The wings on his current
model flap at 275 times per second—faster than the insect's own
wings—and make the blowfly's signature buzz. "Carbon fiber outperforms
fly chitin," he said, with a trace of self-satisfaction. He pointed out
a protective plastic box on the lab bench, which contained the fly-bot
itself, a delicate, origami-like framework of black carbon-fiber struts
and hairlike wires that, not surprisingly, looks nothing like a real
fly. A month later it achieved liftoff in a controlled flight on a
boom. Fearing expects the fly-bot to hover in two or three years, and
eventually to bank and dive with flylike virtuosity.

To find a biomimetic bot already up and running—or at least
ambling—one need only cross the bay to Palo Alto. Ever since the fifth
century B.C., when Aristotle marveled at
how a gecko "can run up and down a tree in any way, even with the head
downward," people have wondered how the lizard manages its
gravity-defying locomotion. Two years ago Stanford University
roboticist Mark Cutkosky set out to solve this age-old conundrum, with
a gecko-inspired climber that he christened Stickybot.

In reality, gecko feet aren't sticky—they're dry and smooth to the
touch—and owe their remarkable adhesion to some two billion
spatula-tipped filaments per square centimeter on their toe pads, each
filament only a hundred nanometers thick. These filaments are so small,
in fact, that they interact at the molecular level with the surface on
which the gecko walks, tapping into the low-level van der Waals forces
generated by molecules' fleeting positive and negative charges, which
pull any two adjacent objects together. To make the toe pads for
Stickybot, Cutkosky and doctoral student Sangbae Kim, the robot's lead
designer, produced a urethane fabric with tiny bristles that end in
30-micrometer points. Though not as flexible or adherent as the gecko
itself, they hold the 500-gram robot on a vertical surface.

But adhesion, Cutkosky found, is only part of the gecko's game. In
order to move swiftly—and geckos can scamper up a vertical surface at
one meter per second—its feet must also unstick effortlessly and
instantly. To understand how the lizard does this, Cutkosky sought the
aid of biologists Bob Full, an expert in animal locomotion, and Kellar
Autumn, probably the world's foremost authority on gecko adhesion.
Through painstaking anatomical studies, force tests on individual gecko
hairlets, and slow-motion analysis of lizards running on vertical
treadmills, Full and Autumn discovered that gecko adhesion is highly
directional: Its toes stick only when dragged downward, and they
release when the direction of pull is reversed.

With this in mind, Cutkosky endowed his robot with seven-segmented
toes that drag and release just like the lizard's, and a gecko-like
stride that snugs it to the wall. He also crafted Stickybot's legs and
feet with a process he calls shape deposition manufacturing (SDM),
which combines a range of metals, polymers, and fabrics to create the
same smooth gradation from stiff to flexible that is present in the
lizard's limbs and absent in most man-made materials. SDM also allows
him to embed actuators, sensors, and other specialized structures that
make Stickybot climb better. Then he noticed in a paper on gecko
anatomy that the lizard had branching tendons to distribute its weight
evenly across the entire surface of its toes. Eureka. "When I saw that,
I thought, Wow, that's great!" He subsequently embedded a branching
polyester cloth "tendon" in his robot's limbs to distribute its load in
the same way.

Stickybot now walks up vertical surfaces of glass, plastic, and
glazed ceramic tile, though it will be some time before it can keep up
with a gecko. For the moment it can walk only on smooth surfaces, at a
mere four centimeters per second, a fraction of the speed of its
biological role model. The dry adhesive on Stickybot's toes isn't
self-cleaning like the lizard's either, so it rapidly clogs with dirt.
"There are a lot of things about the gecko that we simply had to
ignore," Cutkosky says. Still, a number of real-world applications are
in the offing. The Department of Defense's Defense Advanced Research
Projects Agency (DARPA), which funds the project, has it in mind for
surveillance: an automaton that could slink up a building and perch
there for hours or days, monitoring the terrain below. Cutkosky
hypothesizes a range of civilian uses. "I'm trying to get robots to go
places where they've never gone before," he told me. "I would like to
see Stickybot have a real-world function, whether it's a toy or another
application. Sure, it would be great if it eventually has a lifesaving
or humanitarian role.…"

His voice trailed off, in a wistful, almost apologetic tone I had
heard undercutting the optimism of several other biomimeticists. For
all their differences in background, temperament, and ultimate aims,
most practitioners conclude their enthusiastic discourses on their
bio-inspired invention with a few halfhearted theories on how it may
someday make its way into the real world. Often it sounds like wishful
thinking.

For all the power of the biomimetics paradigm, and the brilliant
people who practice it, bio-inspiration has led to surprisingly few
mass-produced products and arguably only one household word—Velcro,
which was invented in 1948 by Swiss chemist George de Mestral, by
copying the way cockleburs clung to his dog's coat. In addition to
Cutkosky's lab, five other high-powered research teams are currently
trying to mimic gecko adhesion, and so far none has come close to
matching the lizard's strong, directional, self-cleaning grip.
Likewise, scientists have yet to meaningfully re-create the abalone
nanostructure that accounts for the strength of its shell, and several
well-funded biotech companies have gone bankrupt trying to make
artificial spider silk. Why?

Some biomimeticists blame industry, whose short-term expectations
about how soon a project should be completed and become profitable
clash with the time-consuming nature of biomimetics research. Others
lament the difficulty in coordinating joint work among diverse academic
and industrial disciplines, which is required to understand natural
structures and mimic what they do. But the main reason biomimetics
hasn't yet come of age is that from an engineering standpoint, nature
is famously, fabulously, wantonly complex. Evolution doesn't "design" a
fly's wing or a lizard's foot by working toward a final goal, as an
engineer would—it blindly cobbles together myriad random experiments
over thousands of generations, resulting in wonderfully inelegant
organisms whose goal is to stay alive long enough to produce the next
generation and launch the next round of random experiments. To make the
abalone's shell so hard, 15 different proteins perform a carefully
choreographed dance that several teams of top scientists have yet to
comprehend. The power of spider silk lies not just in the cocktail of
proteins that it is composed of, but in the mysteries of the creature's
spinnerets, where 600 spinning nozzles weave seven different kinds of
silk into highly resilient configurations.

The multilayered character of much natural engineering makes it
particularly difficult to penetrate and pluck apart. The gecko's feet
work so well not just because of their billions of tiny nanohairs, but
also because those hairs grow on larger hairs, which in turn grow on
toe ridges that are part of bigger toe pads, and so on up to the
centimeter scale, creating a seven-part hierarchy that maximizes the
lizard's cling to all climbing surfaces. For the present, people cannot
hope to reproduce such intricate nanopuzzles. Nature, however,
assembles them effortlessly, molecule by molecule, following the recipe
for complexity encoded in DNA. As engineer Mark Cutkosky says, "The
price that we pay for complexity at small scales is vastly higher than
the price nature pays."

Nonetheless the gap with nature is gradually closing. Researchers
are using electron- and atomic-force microscopes, microtomography, and
high-speed computers to peer ever deeper into nature's microscale and
nanoscale secrets, and a growing array of advanced materials to mimic
them more accurately than ever before. And even before biomimetics
matures into a commercial industry, it has itself developed into a
powerful new tool for understanding life. Berkeley animal locomotion
expert Bob Full uses what he learns to build running, climbing, and
crawling robots—and they in turn have taught him certain fundamental
rules of animal movement. He has discovered, for example, that every
land animal, from centipedes to kangaroos to humans, has precisely the
same springiness in its legs and generates the same relative energy
when it runs. Kellar Autumn, the gecko-adhesion specialist and a former
student of Full's, regularly borrows bits of Cutkosky's Stickybot to
compare them with the animal's natural structures and to test central
assumptions about gecko biology that cannot be learned from the geckos
themselves.

"It's no problem to apply a 0.2 Newton preload to a patch of gecko
adhesive and drag it in a distal direction at one micron per second,"
Autumn says. "But try asking a gecko to do the same thing with its
foot. It'll probably just bite you."

SEE THE FANTASTIC PHOTOGRAPHS ON THE SITE

http://ngm.nationalgeographic.com/2008/04/biomimetics/clark-photography

see also

http://www.guardian.co.uk/science/2008/jun/24/animalbehaviour.usa

A whale of a turbine

• McClatchy newspapers
• guardian.co.uk,
• Tuesday June 24 2008 17:34 BST
• Article history

A humpback whale breaches off the coast of Gloucester, Massachusetts. Photograph:Mary Schwalm/Reuters

A
West Chester University professor has developed a new wind turbine that
draws inspiration from a blubbery source: the flippers of a humpback
whale.

Those knobby flippers were long considered one of the oddities of the sea, found on no other earthly creature.

But
after years of study, starting with a whale that washed up on a New
Jersey beach, Frank Fish thinks he knows their secret. The bumps cause
water to flow over the flippers more smoothly, giving the giant mammal
the ability to swim tight circles around its prey.

What works in
the ocean seems to work in air. Already a flipperlike prototype is
generating energy on Canada's Prince Edward Island, with twin,
bumpy-edged blades knifing through the air. And this summer, an
industrial fan company plans to roll out its own whale-inspired model -
moving the same amount of air with half the usual number of blades and
thus a smaller, energy-saving motor.

Some scientists were
sceptical at first, but the concept now has gotten support from
independent researchers, most recently some Harvard engineers who wrote
up their findings in the respected journal Physical Review Letters.

"There's definitely something going on with these bumps," said Ernst A van Nierop, the paper's lead author.

The saga starts with Fish, a tae kwon do black belt who breaks boards to demonstrate muscle control to his anatomy students.

Fish
is a sort of modern-day cousin of the Wright brothers, in that he seeks
inspiration from the animal kingdom. He's a professor of biology at
West Chester, sharing his office with a small alligator named Wally,
but a more specific term for him is functional morphologist.

Why
are animals built the way they are? Which features - limbs, tails,
noses - give them an edge in propulsion, conserving energy, avoiding
predators?

Fish's research is born of pure scientific curiosity,
his interest ranging from muskrats to alligators. But many want to use
his insights for human technology, convinced that we can learn a few
tricks from what nature has evolved over millions of years.

So
now he is working with the military to develop submarine robots
inspired by manta rays. And he's studying the nasal cavity of the
shark, which might lead to developing an artificial nose.

The first of these animal-inspired ideas to reach fruition is the whale-flipper wind turbine.

Fish was visiting Boston about 25 years ago when he and his wife wandered into a gallery that featured sculptures of animals.
One
was a small rendition of a humpback whale. Fish hadn't worked much with
marine creatures at the time, but he was pretty sure the sculptor had
made a mistake. There were bumps on the front edge of the mammal's
flippers. Fish was sure they belonged on the rear edge.

The
gallery owner overheard him making a derisive remark, and brought over
a brochure with a photograph of the humpback. Indeed, the bumps were on
the front.

"It just drove me insane," recalls Fish, now 55. "Because why should that be?"

Determined to find out, he put in a request for a flipper specimen
from
the Smithsonian Institution. Museum officials finally called years
later, around 1990, to tell him a dead humpback had washed ashore in
New Jersey. He was welcome to come get a flipper at the Marine Mammal
Stranding Center in Brigantine, but he had to cut it off.

He was
told the whale was about 20 feet long. Knowing that a humpback's
flippers are about one-third of its body length, Fish estimated that
one of the flippers would measure 6 feet. A tight fit for his Mercury
Lynx hatchback, but he could manage.

Then he got there and found
the whale was closer to 30 feet, the flipper 10 feet. He had brought
his Black & Decker crosscut saw with him, but it took hours to cut
the flipper into three sections. Each piece weighed more than 100
pounds, and he watched his rear bumper sag more and more as he placed
each piece in the trunk.

"I drove back in absolute fear that a
New Jersey state trooper would stop me, having rotting body parts in
black plastic bags," he says.

The pieces spent two years in the
freezer. Fish couldn't get anyone to make a cast of the giant frozen
pieces, so he couldn't make a model to study it.

Eventually, he
and colleague Jan Battle cut the pieces into 1-inch sections - failing
with a series of smaller saws until they used a butcher-quality model
at the University of Pennsylvania's veterinary pathology lab.

As they had expected, they found the flipper's cross-section looked rather like that of a wing. But what were the bumps for?

One
of the ways an airplane pilot generates lift is by increasing the
wings' angle of attack. The front edge of the wing is tilted upward,
deflecting the oncoming wind so that the wing rises. The phenomenon is
the same as when you stick your hand out the window of a speeding car.

But
if the angle is increased too much, the air rushing over the top of the
wing becomes turbulent, tumbling over itself in undesirable eddies. The
wing will stall.

Yet when models of the bumpy flippers were
tested in a wind tunnel, Fish and his colleagues found something
interesting. The flippers could be tilted at a higher angle before
stall occurred.

The scientific literature had scant reference to
the flipper bumps, called tubercles. Fish reasoned that because the
whale's flippers remained effective at a high angle, the mammal was
therefore able to manoeuvre in tight circles.

In fact, this is how it traps its prey, surrounding smaller fish in a "net" of bubbles that they are unwilling to cross.

In
2004, along with engineers from the US Naval Academy and Duke
University, Fish published hard data: Whereas a smooth-edged flipper
stalled at less than 12 degrees, the bumpy, "scalloped" version did not
stall until it was tilted more than 16 degrees - an increase of nearly
40 percent.

Fish then partnered with Canadian entrepreneur
Stephen Dewar to start WhalePower, a Toronto-based company that
licenses the technology to manufacturers. They have since made airfoils
that can be tilted even more before stalling, up to 30 degrees - though
in the real world they wouldn't go that high, in part because of an
unwelcome increase in the resistant force known as drag.

Exactly
why the tubercles work is not fully understood; there may be more than
one reason. Those who've studied the bumps agree that somehow they
delay "separation" - the fateful turbulence that is associated with
stall.

A key seems to be the difference in pressure between the
air rushing over the tubercles and the air channelled through the
"troughs" in between.

Last summer, a traditional wind turbine was
modified with bumpy blades and is being tested by the Wind Energy
Institute of Canada.
And Envira-North Systems, a maker of industrial
fans in Seaforth, Ontario, plans to have a bumpy-bladed model on the
market by the end of the summer.

"I was a sceptic at the
beginning," said Stephan Gingras, the fan company's research and
development manager. "I'm not a sceptic anymore."

It has all been
a bit of a culture shock for Fish, who is more at home in the open
world of academia than the more secretive realm of inventions and
patents. Two decades ago, his only motivation was to figure out what
the bumps were for.

"I sort of found something that's in plain
sight," he says. "You can look at something again and again, and then
you're seeing it differently."

More http://www.firstscience.com/SITE/editor/0154_ramblings_31082006.asp

Nature-Inspired Design

- 31 Aug 2006

By Sandrine Ceurstemont
  


Page 1 of 2

Photo courtesy of Grimshaw

Look familiar? The structure of sycamore seeds inspired
the design of this 10MW aerogenerator turbine. (Developed by Wind Power
Limited, architectural design by Grimshaw)

Next time you are thinking of crushing a beetle, perhaps you should
admire it instead. Beetles, flies, fish and even sycamore seeds are
proving to be inspirational to engineers and scientists trying to come
up with new and efficient designs. Although humans are great at coming
up with innovative ways of solving problems, often nature has already
done the work through billions of years of evolution and natural
selection to help species survive in a variety of conditions.

Grimshaw is an international architecture firm that is
working on some major infrastructure projects that are not only
inspired by nature but will also help preserve it. One of their
creations is an aero-generator turbine - a wind turbine that looks a
lot like a sycamore seed but with propellers that can each be as tall
as the Eiffel tower. Currently being tested in the lab in preparation
for trials next year, these turbines are designed to be rigged up in
the ocean and can produce up to 20 megawatts of electricity - almost
five times as much as existing wind turbines.

Another project involves designing a desalination plant that is easy
on the eyes and doesn't consume huge amounts of energy. These are
essential in countries that experience water shortages since they
provide a way of removing salt from seawater to obtain usable
freshwater.

Designer Charlie Paton came up with an innovative design by studying
the Namibian fog-basking beetle. The shells of these insects act as a
condensing surface for moisture, allowing them to survive in harsh
desert climates. Based on this mechanism, Paton created a structure
made of glass and steel that uses evaporators, condensers and a minimal
amount of energy to extract freshwater.

- 31 Aug 2006

By Sandrine Ceurstemont
  


Page 2 of 2

Photo courtesy of DaimlerChrysler

The design of the Bionic concept car was inspired by the body structure of the boxfish (above).

But Grimshaw is far from the only place where nature is
inspiring design, in fact this process has spawned a whole field called
biomimetics. Even DaimlerChrysler, a huge automotive company, has
recently designed a new concept car based on the shape and lightweight
body structure of the boxfish. Again, the solution that this design
seems to provide is an energy-saving and aerodynamic construction -
which the boxfish has already mastered.

Biomimetics is becoming so popular that Dr Julian Vincent, the
director of the Centre for Biomimetic and Natural Technologies at the
University of Bath in the U.K., has created a database of biological
"patents" that engineers can access if they want to research how nature
has dealt with a problem they are trying to solve. By searching the
database with a keyword like 'propulsion', a person can access
information about the propulsion mechanisms used by different animals,
for example jellyfish, frogs or flying squirrels. Although the database
is still in the works, it currently contains over 2,500 "patents" that
engineers can work with.

So for those of you with creative energy flowing through your veins,
it could be a good place to start - that or taking a closer look at
your environment. If Swiss engineer George de Mestral hadn't examined
how burrs kept attaching themselves to his dog's fur, then we would all
still be tying our shoelaces. Yes, I know: most of you probably are,
but I'm a fan of Velcro and the carefree 80's.

For more info:

University of Bath - Biomimetics
http://www.bath.ac.uk/mech-eng/biomimetics/about.htm

Biomimetics at Bath is expanding quickly, and we will soon have
many more projects up and running.  Here are the ones so far:

Jumping robots |
Adaptive fabrics | Automatic Assembly | Mimicking social insect building | TRIZ

The Guardian - Engineers race to steal nature's secrets
http://environment.guardian.co.uk/energy/story/0,,1860250,00.html

Engineers race to steal nature's secrets
Giant wind turbines based on a seed, and desalination plant that mimics a beetle

• John Vidal, environment editor
• The Guardian,
• Tuesday August 29 2006

A new generation of small green
companies is emerging with radical but proven ideas to revolutionise
engineering and create anything from intelligent fridges to colossal
wind turbines moored at sea.

The designers hope their projects
will transform energy supplies and cut carbon emissions in the next 20
years. They include huge wind turbines, more powerful than any seen
before, anchored to the seabed 20 miles off the coast; fridges that
monitor the national grid to use less power; a desalination plant that
is also a theatre; and a tidal lagoon that protects the coast while
generating electricity.

The new companies are rethinking major
infrastructure projects using natural objects as their basis. The
aero-generator turbine, now being laboratory tested before sea trials
next year, mimics sycamore seeds that spin like propellers in the
slightest breeze. Its twin arms could each be as tall as the Eiffel
tower, and the structure could be moored like an oil platform in 450
feet of water.

Each turbine, said Martin Pawlyn, an architect
with Grimshaw - which developed the transparent "biomes" at the Eden
Project in Cornwall - could produce 20 megawatts of electricity, nearly
five times as much as any existing wind turbine. "A cluster of 100 of
them spread over just a few square miles of ocean, each turning at just
a few revolutions a minute, could outperform almost all Britain's
existing wind farms put together," he said.

"We are now learning
from natural eco-systems, and are scaling up projects. We are going
back to first principles, taking our inspiration from nature."

The
desalination plant, essential in countries that suffer water shortages,
is also being rethought. Mostly banished to the edges of cities, they
are disliked for needing large amounts of energy and looking like
ill-designed boxes. Architects working with designer Charlie Paton have
developed one that needs next to no energy and can double up as an
open-air theatre. It has been proposed by Grimshaw for the city of Las
Palmas in the Canary Islands, historically short of fresh water.

The
structure, looking like a wall of glass and steel, uses simple
evaporators and condensers to produce large quantities of fresh water.
"The inspiration came from the Namibian fog-basking beetle, which uses
its shell as a condensing surface for moisture, which allows it to
survive in the desert," said Mr Pawlyn. "There are countless other
examples like this that we can turn to when tackling some of the
environmental issues that we now face."

The idea has been used in
three commercial greenhouses in the Middle East to grow food using salt
water. Seawater cools and humidifies the air in the greenhouse and
sunlight distils fresh water.

A radical but simple design
proposed for north Wales is a 15km-long tidal energy scheme that could
generate up to 450 megawatts of power and protect the coastline from
erosion and severe storms. It could be constructed from dredged sand
and seabed material, or waste slate from disused Welsh quarries. Long
rows of hydroelectric generators would turn and generate electricity as
the tide rushes in and out. North Wales has some of the highest tidal
ranges in the world.

"It would protect Rhyl and neighbouring
towns with 30 linear miles of breakwater, reducing the risk of flooding
disasters like the one in 1990. But it would not be visually intrusive.
It works well with wind power, and it would even be possible to move
it," said Mr Pawlyn.

The scheme could also offer a natural but
nearly invisible shelter, allowing a marina to be built and a depressed
area of north Wales to be regenerated. "We are trying to raise the
utilitarian [infrastructure project] to another level. It's the idea of
celebrating nature, and learning from it to rethink environmental
problems," said Mr Pawlyn.

Other ideas being developed include
sewage treatment processes that generate 20% more electricity than
usual, and giant solar heaters that would concentrate sunlight on to
solar cells, producing 30 times as much electricity as today's cells.

Mark
Shorrock, a director of venture capital firm Low Carbon Accelerator,
which is aiming to raise £50m to back dozens of small green technology
companies, said the market for imaginative, new renewable energy
technologies was taking off, and was expected to more than double in
the next few years. Solar energy is expected to be a £50bn market by
2015.