Month: November 2014

Thermodynamic Whoopee

man without a countryThe success of our students in the MyCopter project inspired me a couple of weeks ago to write about the prospect for flying cars [see post on October 2nd, 2014 entitled ‘Origami car-planes‘], which are not good essentially because we don’t know how to manipulate gravity. Everything in the universe is controlled by four forces, i.e. electromagnetic, gravitational, weak nuclear and strong nuclear. Adam Frank, described our understanding and control of electromagnetic forces as god-like because we can manipulate photons, electrons and atoms with enormous precision in flat screen TVs, mobile phones, microwave ovens and much more.

Strong nuclear forces hold protons and neutrons together in the nucleus of atoms and weak nuclear forces control the fusion process in stars. We have managed to take a few tottering steps to control nuclear forces in nuclear power stations but we are blundering apprentices compared to our skills with electromagnetism. However, with gravitational forces we are like toddlers trying to feed ourselves – we have some idea about what we are supposed to be doing but we waste an enormous amount in trying to hit the target. So we use our expertise in electromagnetism to combust fuel in an engine which drives an aerofoil through air faster enough to generate lift. This usually involves burning vast amount of fossil fuel and it gets worse when you want to hover with rotating blades or a vertical jet. Kurt Vonnegut in a ‘A Man without a Country‘ has described our reckless use of fossil fuel as making ‘thermodynamic whoopee’ but if we want fly long distances with significant payloads we don’t have much choice at the moment.

If physicists could work out how to manipulate gravitational forces it would not take engineers long to design and build flying cars that would be as advanced relative to today’s private jet as your tablet computer is relative to an abaqus.

Source:

I was promised flying cars‘ by Adam Frank in the New York Times on June 6th, 2014

‘Crash’ in Taipei: an engineer’s travelogue

taipei101

Taipeo 101

When you land at Taipei Taoyuan International airport, you could be forgiven for thinking that you have arrived at some as yet unvisited Floridian city. The palm-trees, architecture, layout and feel of the terminal is very reminiscent of a major airport in the USA, though perhaps slightly Ballardian. The yellow cabs collecting passengers from the curb outside the spacious terminal reinforce the impression, except that most of them look like a Toyota Prius. But, once you arrive downtown, overtones of a Mods’ weekend at Brighton takeover as scores of scooters roar away from every traffic light when they turn green leaving. In every other way Taipei is a modern, sophisticated Asian city with its towering skyscrapers, including Taipei 101, designer stores, back streets full of tiny shops and busy traffic.

Beijing residents have wholeheartedly taken to the electric motorbike and you have to be careful crossing the road not to be knocked down by these silent two-wheelers. Whereas Taipei residents seem to love their noisy scooters, but Taipei is largely smog-free so maybe there is less incentive to switch to electric bikes.

I said Ballardian above because the road to Taipei from the airport reminded me of the ‘Crash’ by J.G. Ballard. The freeway has been expanded along almost its entire length by constructing additional elevated carriage-ways on both sides, so that on the original freeway you feel fenced in by concrete pillars and bridge-sections.

Some of you might be wondering why I have been wandering around Asia. Well, I visited Beijing and Tianjin [see last week’s post] to give a series of seminars as the Hsue-Shen Tsien Professor of Engineering Sciences at the Chinese Academy of Sciences’ Institute of Mechanics. Then, I went to Taiwan to participate in a bilateral workshop with National Tsing Hua University and to meet with research students on our dual PhD programme.  ‘The World is Flat’ as Thomas Friedman wrote and engineers are a driving force in the global economy, so its not unusual to find engineers abroad either on short trips or living overseas.  Yet, I am constantly surprised by the lack of enthusiasm amongst most UK students to participate in international exchanges, even though such experience increases their employability.

Mass produced nuclear power plants?

A slightly weird picture of the rather unusual House of Porcelain in Tianjin, which is slowly turning black in the smog.

Porcelain House in Tianjin, which is slowly turning black in the smog.

In the pocket of my coat I have a peculiar souvenir of my recent visit to China. It’s a white face-mask with a little filter built-in to one side. It cost 2 Yuan, or about £0.2, and was given to me by a research student in Tianjin, who worked in my lab in Liverpool for a year. She bought it for me one Saturday when we were going out sightseeing in Tianjin because the air quality was so poor it caught on the back of your throat. The smog was so thick you could not see the tops of even modestly tall buildings.

This is a daily reality for millions of people in many of China’s cities. I reported in my blog entitled ‘Year of the Air: 2013’ [November 20th, 2013] about the number of deaths from pollution.  PM2.5 that’s particles with a diameter less than 2.5 microns are damaging to human health. While I was in Beijing the level of PM2.5 was 144 micrograms per cubic metre, compared to 13 at home in Liverpool.  My student’s mother had visited her while she was in Liverpool and I asked what she liked most during her visit – the fresh air was her reply.

I can’t really remember smog in England though I do remember buildings in the city centres being gradually cleaned because the smog had turned them black. And I remember shortly after I finished my PhD, being shown by a collaborator in the Pathology Department, the lungs from a recent post-mortem – they were grey-black from the smog!

The scale of the problem is difficult to grasp. Tianjin is a provincial city about 30 minutes by bullet train south-east of Beijing with a population of 14 million people, almost twice that of London, and 2.4 million cars.  The smog is generated by pollution from factories, power-stations and cars.  Hybrid cars could make a difference but there are none because they are too expensive, a Beijing colleague told me as he drove me in his brand new Volkswagen Passat. Plug-in cars would not solve the problem because the electricity would come mainly from coal-fired power stations, so the pollution would be simply moved elsewhere.

China needs clean energy, fast and lots of it.  In 2011 China’s installed electricity generating capacity was  about 1TW (Tera Watts or 1 with 12 noughts after it), of which about 2% comes from China’s 21 operating nuclear power plants.  Typical modern nuclear power plants take years to build and generate around 1,000 MW; perhaps we should be considering the small-scale mass production of medium-size modular power plants.  Huge, complex, reliable aeroplanes are made in this way, for instance the current Airbus A380 is production rate is about 25 per year.  So why not medium-size nuclear power plants?  Mass-production would also make decommissioning cheaper since it not be a bespoke process for each plant.

Maybe now that the Lockheed Martin’s Skunk Works have turned their attention to developing a fusion reactor, power-stations will be produced like airliners before I retire.

Sources:

Porcelain House, Tianjin

http://blogs.wsj.com/chinarealtime/2014/10/27/desperate-measures-as-world-leaders-visit-beijing-tries-to-reduce-pollution-by-40/

http://aqicn.org/city/united-kingdom/liverpool-speke/

BTW – My pathology colleague and I were interested in whether people with osteoporosis could break their hips and fall, rather than the usual assumption of falling and break their hips. See:

Wilkinson JM, Cotton DWK, Harris SC & Patterson EA, Assessment of osteoporosis at autopsy: mechanical methods compared to radiological and histological techniques, Medicine, Science & the Law, 31(1):19-24, 1991.

Cotton DWK, Whitehead CL, Vyas S, Cooper C & Patterson EA, Are hip fractures caused by falling and breaking or breaking and falling? Forensic Science Int., 65(2):105-112, 1994.

 

 

Entropy management for bees and flights

entropy_vectorEngineers like to apply the second law of thermodynamics to chemical processes and power generation cycles. However, it has some useful lessons for everyday life since it can be paraphrased as ‘whenever you organise any process expect some disorder, or entropy to be generated’, so a shrewd person plans for disorder and designs in a bit of slack or redundancy.

Bob and I gave an example of this in our book, ‘The Entropy Vector’.  We pointed out that if you plan your flight schedule to use all of the available gates at an airport then you will have unhappy passengers when flights are delayed, unless you plan for buses to unload planes parked away from the terminal. European airports tend to be good at this whereas US ones tend to leave passengers in planes that are unable to dock at the terminal.

Our example was inspired by frustrating experiences when we were writing the book. A more topical and important example was raised by Mark Winston in the New York Times on July 14th, 2014 in reporting the importance of bees to farming. His research team found that crop yields were maximised when large acreages were left uncultivated to support wild pollinators. He postulated that a variety of wild plants means a healthier, more diverse bee population which will be more active in the planted fields next door. Their numbers were startling with profits more than doubling for farmers that left a third of their acreage fallow. Winston highlights that this contravenes conventional wisdom that bees and fields can be micromanaged.

This seems like reinventing the wheel because I remember being taught about the importance of crop rotation, including a fallow period, in my ‘middle’ school geography classes. Oh dear, now I am showing my age.

The bottom-line is don’t micromanage. Allow for a bit of inefficiency, not too much of course or your competitors will get ahead! It’s a question of balance.