Thursday, 5 February 2015

Biomimicry: city design, textile colouring and much else

Water Wall
One approach to keeping the biosphere evolving in a sustainable way is to concentrate on new and existing cities and aim to give them the same ecological footprint as the terrain they cover. It is in cities that over half the world population lives and there seems to be a general consensus that this proportion will continue to increase.

Making a city fit into its ecological niche is much easier for a new city: it can be designed from scratch to store water and emit gases (cabon dioxide, oxygen, water vapour etc.) in similar quantities to, say, a deciduous forest as well as sustain a small amount of local flora and fauna within its boundaries and not cause local soil erosion or pollution.

Some 400 new cities will be needed, for example, to help accomodate the rapidly growing population of India, so it is important to get the design principles right. The methods developed could to some extent be applied retrospectively to existing cities and urban sprawls throughout the world.

A pioneer of biomimicry of cities is Janine Benyus who is working with her colleagues at the Biomimicry Guild and with large corporations such as Walmart, Nike and Interface. Currently she appears to be working with HOK, a large architectural developer, on two major projects: one to build a city from scratch in India and one to retrofit an existing city in China.

What I find encouraging is that after her book Biomimicry: Innovation Inspired by Nature was published in 1997 Benyus was approached more by business leaders than by green activists.

Biomimicry is much broader in scope than city design and involves mimicking nature to achieve more efficient, ecologically sound technology.

 For instance, most butterflies wings only use one pigment, a brown one(?): all the other colours are produced by their microscopic surface structure which reflects and refracts light in a similar way to the droplets of a rainbow. The textile industry is now beginning to colour some of its fabrics this way, so that pigments and dyes don’t have to be used. This should reduce pollution while at the same time providing scope for striking optical effects in the fashion business.

Further examples of how nature offers engineering solutions (these are just a few out of thousands):
  • The abalone, an ear-shaped shell with a pearly interior, generates an inner shell twice as tough as the best ceramics.
  • Diatoms (unicellular algae with silica impregnated cell walls) make glass from seawater and require no furnaces.
  • Spiders manufacture silk as strong as Kevlar (used in bullet-proof vests) and tougher, but without boiling sulphuric acid or high-temperature extruders. Digested crickets and flies are the only raw materials.
  • Trees turn sunlight, water and air into cellulose, which is stiffer and stronger than nylon, and bind this into wood.
  • Snake inspired robots imitating the snake's body shape and movements. E.g. remotely controlled hose for fire fighting.
  • New type of cement based on coral chemistry.
  •  Boat hulls based on shark skin design for hydrodynamic efficiency and reduction in papasite growth.
  • Painless hypodermic needle is being developed which is inspired by the way mosquitos bite
  • Bullet train with a beak inspired by the design of a Kingfisher's bill. This avoids noise pollution when the train emerges from a tunnel.
  • Camouflage researchers are copying the way this is done in nature, e.g. by the octupus.
  • Air conditioning inspired by the air cooling in a termite nest by complex porous surface that generates airflow through the tunnel.

 Certain strains of algae when deprived of sulphur produce hydrogen by photosynthesis instead of oxygen. R&D on this is has been pursued at the Argonne National Laboratory (US Department of Energy) and if successful the hydrogen could be used for fuel cells. Strictly, this is the modification and exploitation of a biological system  rather than mimicry. The economic and sustainability implications would be enormous.
Biomimicry and adaptation of natural systems could do a lot to give us a more sustainable, cleaner and more attractive environment and provide fulfilling employment as the western economies try to escape depression.

 God/nature has provided us with a gift and it would be ungracious/stupid to refuse it.