Monday, November 26, 2012

Copying Nature

Wired highlights another design concept which copies a feature from nature:
The beetle, endemic to Africa’s Namib desert — where there is just 1.3cm of rainfall a year — has inspired a fair few proof-of-concepts in the academic community, but this is the first time a self-filling water bottle has been proposed. The beetle survives by collecting condensation from the ocean breeze on the hardened shell of its wings. The shell is covered in tiny bumps that are water attracting (hydrophilic) at their tips and water-repelling (hydrophobic) at their sides. The beetle extends and aims the wings at incoming sea breezes to catch humid air; tiny droplets 15 to 20 microns in diameter eventually accumulate on its back and run straight down towards its mouth.
NBD Nano, made up of two biologists, an organic chemist and a mechanical engineer, is building on past studies that constructed structurally superior synthetic copies of the shell. An earlier incarnation of the material was first constructed in 2006 by an MIT team — they dipped glass or plastic substrates into solutions of charged polymer chains over and over again to manipulate the surface make-up. Silica nanoparticles were then added to create a rougher, water-trapping texture, and a Teflon-like substance sealed it. Charged polymers and nanoparticles were then layered in patterns to create a contrast between rough and porous surfaces.

NBD Nano says it has achieved proof of concept with its dual water-attracting (superhydrophilic) and water-repelling (superhydrophobic) bottle design, and is currently working on a prototype and seeking funding. Incredibly, the team predicts that the bottle could collect between half a litre and three litres of water per hour, depending on the local environment.
There are a lot of things we can find in nature which can become immense improvements in our lives if we figure out how to harness them.  Here's another one I saw this weekend:
The Plant-Microbial Fuel Cell draws electricity from the soil while the plants continue to grow. Plants produce organic material via photosynthesis. The roots excrete up to 70 % of this material (unused) into the soil. Bacteria around the roots break down the organic residue, thereby forming a new source of electricity. The degradation processes causes electrons to be released. Marjolein Helder and her colleagues placed an electrode close to the bacteria to absorb these electrons and generate electricity via the potential difference thus created. The Plant-Microbial Fuel Cell can currently generate 0.4 Watt per square metre of plant growth. This is more than is generated by fermenting biomass. In future, bio-electricity from plants could produce as much as 3.2 Watt per square metre of plant growth. This would mean that a roof measuring 100 m2 would generate enough electricity to supply a household (with an average consumption of 2,800 kWh/year). Plants of various species could be used, including grasses such as common cordgrass and, in warmer countries, rice.
Nothing may come of these ideas, but it makes sense to try to take advantage of potential breakthroughs we can find in the natural world.  Heck, doing so gave us velcro, and we all know how revolutionary that was.  I mean, it keeps my wallet closed up.

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