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Sunday, Aug. 24, 2008
Natural by design
'Biomimicry' creates sustainable technology from the fruits of evolution
Special to The Japan Times
I magine being able to maintain a perfect temperature and humidity in your home year round, without spending a single yen in electricity or gas bills. That's exactly what Professor Emile Ishida of Tohoku University in northern Japan is striving to achieve — and he got the idea from termites.
After all, as any zoologist will tell you, Macrotermes michaelseni, termites that are native to parts of Africa, maintain just such a perfectly controlled environment inside their nests despite outside temperatures that can fluctuate from near freezing to 40 degrees and beyond.
Unlike most termites found in Japan and many other temperate parts of the world, M. michaelseni cannot directly digest the wood and other plant material they harvest. Instead, they build towering nests of soil where they use the chewed-up plant material to 'farm" a type of fungus. This fungus, which the termites eat, requires a stable 30.5-degree environment in which to grow. Consequently, the termites have evolved their unique ventilation system: Air enters at the base of the nest, circulates through cool chambers underground, and finally flows out at the top of the tower, cooling the nest as it goes. The termites open and close vents throughout the day to keep the temperature even.
These natural wonders of architecture have already inspired a handful of low-energy buildings around the world. Zimbabwean architect Michael Pearce designed one such office complex, called Eastgate, in Harare in 1997. The building utilizes a complex system of vents and fans to circulate air much like a termite mound does, with a resulting reduction in heating and cooling costs of 90 percent.
But Ishida, who spent more than 20 years at tile and building-material manufacturer INAX Corp. before entering academia, had his eye on a different feature of the termite mounds: the fact that they are built of dirt. Soil is not only a good insulator, Ishida says, but its microscopic pores also condense and absorb moisture in the air. This explains the steady humidity levels in termite nests.
Of course, humans have been using soil as a building material for millenniums, but earth dwellings lack the strength demanded today (and make for a dusty house beside). Constructing earth walls like Japan's traditional tsuchi-kabe can also be time-consuming and expensive. While baking earth into conventional bricks and ceramic tiles adds strength, the high temperature they need to be fired at destroys the nanopores vital to humidity control. So Ishida is researching a low-temperature steam treatment for tiles, called hydrothermal processing, which leaves pores intact while increasing strength.
Using these "earth ceramics" as flooring or wall-coverings virtually eliminated the need for air conditioning and heating in experimental trials, Ishida says. This April, he shared his findings with an attentive audience at the Conference for the Promotion of Manufacturing in Tokyo, whose 1,600 members include Canon, Hitachi, and Toyota. He hopes earth ceramics and other ideas inspired by nature will help Japan's manufacturing industry wean itself from fossil fuels as global warming becomes an increasing concern.
Ishida is part of an exploding field called "biomimicry," which looks to nature for sustainable solutions to today's toughest design challenges. Rather than simply harvesting natural resources, biomimicry practitioners see nature as a mentor that can help us improve the way we design our world. In Japan, the field is often called "nature technology" because it draws inspiration from geological as well as biological forms.
Tiny solar batteries inspired by the way leaves turn sunlight into energy; self-cleaning tiles modeled on spotless snail shells; and improvements to Japan's Shinkansen bullet train gleaned from the shape of kingfisher beaks and owl wings are just a few of the ideas biomimicry has spawned in recent years. The field made news again this July when the United States military revealed its study of the African freshwater fish Polypterus senegalus, whose super-protective scales may provide insight into how to create better body armor.
Seeking inspiration in nature is nothing new, of course. Thousands of years ago, the inventors of chopsticks are said to have mimicked the way a bird's beak captures food, and in more recent centuries, Leonardo da Vinci and the Wright Brothers turned to birds once again when designing their flying machines.
However, the past several decades have seen a renewed focus on nature as a source of design ideas. As Bryony Schwan, director of the Montana, U.S.-based Biomimicry Institute puts it, biomimicry is a "revived idea." What's new about this latest reincarnation of biomimicry is that scientists and designers are examining nature at an increasingly microscopic level — and with a greater urgency — as the world runs through its natural resources with dizzying speed.
"Since the Industrial Revolution, we've owed everything to minerals and energy underground," says Ishida. "But within 20 to 30 years, the current manufacturing system will be facing limits."
He believes nature technology, not a lowered standard of living, is the solution.
Biomimicry was brought together as a field of study in 1997, with the publication of American biologist and writer Janine Benyus's book, "Biomimicry: Innovation Inspired by Nature."
In 1998, Benyus founded the Biomimicry Guild, a consulting group whose clients range from Nike to NASA, and in 2005 she started up the nonprofit Biomimicry Institute. Since her book was published, interest in both the research and business communities has mushroomed. A Web search for "biomimicry" and related terms turns up about 23.7 million hits, and between 1985 and 2005 the number of explicitly bio-inspired patents increased from just five in 1985 to 99 in 2005. Meanwhile, Benyus was last year named a Time magazine "International Hero of the Environment" — hurtling the concept of nature-as-mentor even further into the mainstream.
Japan's biomimicry research community is one of the most active in the world, says Benyus. In 2006, she toured the country to promote the Japanese- language release of her book by Ohmsha ("Shizen to Seitai ni Manabu Biomimikuri"). She says her Japanese audiences felt a natural connection to the philosophy behind biomimicry.
"Often after the talk people would come up to me and say, 'This resonates, for two reasons: We revere our elders and we revere nature.' Humans are a very young organism. In biomimicry we are learning from our biological elders, from those 3.8 billion years of experience. These organisms are sensei (teachers); there is so much they can tell us." The living creatures we see around us today, she goes on to point out, are but a tiny fraction that have managed to survive the evolutionary process.
According to Kazunori Kobayashi, a manager at the Tokyo-based nonprofit organization Japan for Sustainability (JFS), the biomimicry field started to heat up in Japan three or four years ago. In April 2004, JFS took on a one-year project to gather examples of biomimicry work. The project, funded by a ¥1.5 million grant from the Hitachi Environmental Fund, also hosted a number of lectures and workshops on the subject.