Category Archives: sustainability

Algae-powered aircraft

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Recently, I attended an event organised by Airbus which included a film about their vision of aviation in 2050 followed by a question and answer session with their VP for Engineering in the UK, Neil Scott.  A strong theme that I took away from the event was maintaining air transport as fossil fuels become scarce and expensive through the use of oceanic algae farmed and harvested to generate biofuels.  This could be a good solution but we will need to consider the environmental impact of the massive level of ocean agriculture required to supply our airline system.  Airbus propose a more balanced, diverse approach to sourcing biofuel in this short video on their website: http://videos.airbus.com/channel/iLyROoafYvHb.html; so perhaps I took away the wrong message from the event I attended.

[Photo from http://cleantechnica.com/2010/07/20/holy-sustainble-cow-ordinary-algae-can-double-as-biofuel-and-cattle-feed-too/%5D

More material

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In previous posts I have mentioned the need for ‘more material’ in order to reduce the probability of failure.  This is a little sloppy, since there are, at least, two options buried in these statements.  Namely, the simple one, which is to add a greater mass of material; and the alternative, which is to use a stronger but lighter material, i.e. a more sophisticated material, e.g. a composite.  These are usually also more expensive but can also provide opportunities to incorporate sustainability via bio-based recyclability [for information on bio-based composites see http://www.ag.ndsu.edu/bioepic/documents/symposium/NDS%20Bio-BasedMaterials-DRZAL-10-07-final.pdf%5D.

Population crunch

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The current growth trends suggest that the global population will increase by a billion in the next few decades, with perhaps 500 million additional people in Africa and the same number in Asia [see http://www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf%5D.  Another observable trend is urbanisation.  Thus, taking these together it is not unreasonable to expect most of the population growth to occur in cities.  The typical size of cities in Africa is 0.5 million people and so we might expect to see 1000 new cities in Africa and perhaps around 500 in Asia where the average size is 1 million.

The challenge for engineers is to provide an acceptable quality of life in these cities.  This involves providing a built environment, food, energy, transport and health care using scientific advances in novel materials, information communication technology, biosciences, electronics and photonics.

Can it be done? Probably, but it will require a higher level of innovation than is the norm at the moment, otherwise the population crunch might take many forms.

Waste is unavoidable

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Image from http://www.nucleartourist.com/systems/ct.htm
Courtesy KKN Liebstadt NPP

If you read my previous post on perfect engines, then you might have thought a heat engine that did not discharge any heat would be more efficient.  However, this would contravene the second law of thermodynamics, which requires that every real process must generate an increase in disorder, in this case by the discharge of waste heat.  Thermodynamicists like to call this increase in disorder, an increase in ‘entropy’.

A consequence of the second law of thermodynamics is that the entropy, or disorder, of the universe is always increasing; but now I have strayed from engineering to physics.  Together with Bob Handscombe, I wrote a book on this topic called the ‘Entropy Vector: Connecting science and business’.  It was not a best-seller but it got some good reviews, see http://www.worldscientific.com/worldscibooks/10.1142/5365#t=reviews.