A spider spins a bulletproof vest
Georges de Mestral went for a walk with his dog, came back and invented the Velcro. It was genius, but the supergenius here was nature. Scientists are looking to nature to teach them, and a new field of learning, biomimetics, has emerged.
Dr. A.V. Srinivasan (right) being felicitated by Prof. Dataguru, Chairman, Dept. of Aerospace Engineering, IISC.
EVER WONDERED how the remarkably nimble dragonfly moves and manoeuvres through the air with such ease? How is that even the most sophisticated manmade flight crafts are yet to achieve such manoeuvrability? Can you imagine what it would be like if you could actually decipher how bats pursue and capture a fleeing moth with the facility and success rate that could make a military aerospace engineer green with envy?
Ever since the man learned to figure out things for himself, he has been observing and learning from nature. This has evolved into a new field of study that tries to mimic nature in the designs and patterns it provides for the survival of an organism.
The term biomimetics was coined in 1972 initially in the context of artificial enzymes but it is broadly defined as "the abstraction of good design from nature". The term came to be applied formally in the late 1980s when the US Air Force initiated research grants in the areas of wood, seashells, and insect cuticles. Thus, it came to be an area that seeks to find new avenues of scientific inquiry and the extent to which these ideas could be incorporated in the analysis, design and development, and manufacture of man-made smart structures that are safe and reliable.
Dr. A.V. Srinivasan, a visiting Professor at the Indian Institute of Science, is one such architect who has given himself to learning from nature ever since he was nominated in 1991 by United Technologies Corporation to serve on the President's Commission on Executive Exchange.
Dr. Srinivasan was posted to the Senior Executive Service and assigned to the US Air Force Office of Scientific Research as Technical Adviser to the Aerospace Directorate, and asked to study the developing field of biomimetics and prepare an authoritative paper on the subject.
According to Dr. Srinivasan, nature assembles the structural systems available, usually in aqueous media under suitable conditions, to form a net shape. "After this there is an integrated design and development of natural organisms with the components entrusted with several functions. The result is a cost effective and durable structure whose performance matches the demands brought upon the living system," he explains.
"Nature has managed to built materials and devices with a breathtaking functionality, heterogeneity, and stability using a comparatively limited number of building blocks, despite the fact that the basic concepts of nature are simple.
The secret, as we know, lies in the manner in which the building blocks and materials are arranged that is said to result in the complex functionality," he simplifies.
Simple examples of biomimicking are Velcro and the Eiffel Tower whose designers have been inspired by the natural world. In fact, it is said that Georges de Mestral invented the Velcro when he saw how a burr, with its series of tiny hooks, stuck so firmly to his dog's fur
David Attenborough, in his famous book Trials of Life, describes the amazing Bracken Cave in Texas, that is home to over 20 million bats. No one has been able to figure out how a mother bat identifies her baby to feed it. She alights within a few feet of where she last left it, calls out for several seconds, and gets a response.
"It is difficult to believe that, among the tumult in the cave, either mother or baby would be able to recognise one another's voices, but bats are famous for their skill in disentangling the echoes of their high-frequency squeaks and using them as a way of navigating.
Imagine the signal to noise ratio, the filtering, processing, that takes place in seconds," writes Attenborough. Similarly a study of the architecture of wood cells led to a promising manmade counterpart composite of fibre-reinforced plastic.
Such a composite material/structure, patented at Reading University in the UK, was based on the concept of a glass fibre reinforced with a plastic composite of helically wound manmade fibrous elements such as glass or carbon hollow tubes.
"The sophistication behind this is extremely high because this kind of simulation requires ability to use nano and micro size fibres along with very sophisticated control systems," explains Dr. Srinivasan.
There are other simple but abundant themes of nature mainly in the form of self-assembly.
Lipids, for example, assemble in sheets to form cell membranes, proteins assemble into functional enzymes, cellular `sensors', fibres, or virus coats, and DNA assembles in double strands to provide the very basis of life, in the form of replication.
"Using these often relatively simple concepts, one could relate the design of a rhino to an army tank; the beetle shell to that of the skin of an aircraft or the design of a dragonfly to that of a fighter aircraft," he says.
The prime philosophy behind biomimetics is that plants and animals, in their struggle for survival, have evolved solutions to problems very similar to ones that scientists and engineers face.
Therefore, by following these solutions researchers feel that their problems too could be solved.
Although there have not been extensive applications, attempts have been made to learn nature's strategies by studying, say, the aerial acrobatics of birds, or the meticulous manner in which strong and tough shells of molluscs are assembled from relatively brittle materials.
"Currently, the principle of biomimetics is being tried to manufacture a patented and tough composite that simulates the architecture of wood and the synthesis of spider silk to produce bulletproof vests," says Dr. Srinivasan.
Considering the newness of the topic even in developed countries, it is certain that India has a long way to go.
However, there are small-scale efforts being made in institutes like the IISc., where efforts are on to develop micro flight vehicles that involve understanding the aerodynamic and control aspects of bird flight.
Dr. Srinivasan agrees that there's no reason that the principle of biomimetics should apply only to defence projects.
He sees great potential for it in India.
However, we must have the will to create, nurture and maintain an innovative environment in universities and research laboratories to make progress.
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