Sonic screwdrivers

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No relevance except for the tranquility or absence of noise.

In a recent post on Noise Transfer [27th March, 2013] I highlighted the parallels between energy transfer by heat and noise.  In many cases, the heat and, or noise transfer is by-product of a process through which energy is dispersed to satisfy the requirements of the second law of thermodynamics, that entropy must increase as a product of all real processes.  Entropy, can be interpreted as a measure of dispersion, or the lack of availability to do anything useful and this applies to most heat and noise that we encounter in everyday life.

We can use concentrated sources of heat to produce useful work such as the furnace in a power station, but the second law of thermodynamics demands that we waste a substantial proportion of it through the creation of entropy.  It is also possible to use concentrated sources of noise, such as ultrasonic transducer to perform useful work for us, such as in surgery and the manufacture of composite materials [see Professional Engineering, http://profeng.com/features/good-vibrations ]; although an all-purpose sonic screw-driver of the kind used by Dr Who is not possible, yet.

Extraordinary technical intelligence

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In his book ‘A History of the World’, Andrew Marr identifies a recurring process in the development of societies, from an agricultural revolution that releases enough people from food production in the countryside to enable basic manufacturing in town and cities, through an industrial revolutions leading to more sophisticated manufacturing and a large, rapid rise in the standards of living.  This process happened first in Britain during the 18th and 19th century, in the US during the 19th and 20th century and then more quickly in Japan, Korea and Taiwan in the second half of the 20th century.  It is happening now and even faster in China with the same ‘grim working conditions in the factories, the raucous enjoyment of plenty by the winners in the cities and a certain recklessness about pollution’ to quote Andrew Marr [Marr, A., A History of the World, MacMillan, 2012].  It is starting in India and Africa might be next, though in the Financial Times on Friday 22nd March, 2013 Chandran Nair argues that we should reverse the flow from the countryside to the cities if we want to achieve a sustainable society.  This might just be possible in Africa, probably not in India and China seems set to follow the well-beaten path to urban industrialisation.

What comes next in the process?  Perhaps a loss of interest in manufacturing industry, followed by over-spending by individuals and governments, economic recession or collapse and stagnation of growth.  Andrew Marr suggests that the wealth based on manufacturing derives from ‘mankind’s extraordinary technical intelligence’ and that there is ‘a long lag in advancing our political and social intelligence’.  The stale-mate at the heart of US politics and the failure of successive UK governments to avert a multi-dip economic recession would suggest the need to advance our political intelligence.  In the meantime we might lose our technical intelligence if don’t train more graduates in technology [see my post on Financial crisis, 27th March, 2013].

Noise transfer

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This is not the author's house!

This is not the author’s house!

We are privileged to have magnificent views of the river and mountains beyond from our city centre house.  However, the house was built before the motor car was invented when the loudest event outside might have been rowdy party-goers heading for home.  We still have some party-goers walking home under our bedroom window at night but most of them travel by noisy taxis.  I look forward to when the price of fossil fuels, or legislation will force taxis to become electric-powered.  In the meantime, we have been designing secondary glazing that will offer a high resistance to noise transmission and be in keeping with the early 19th century windows.  Noise is a form of energy transfer by vibrations, acoustic energy would be an alternative term for it, and so the combined resistance of the outside wall of my bedroom can be calculated using Kirchhoff’s law, as discussed for heat transfer in my last post [Born in a barn, 20th March, 2013].  In this case, the thin and badly-fitting but antique glass is the dominant component of both the heat and noise resistance.  We were happy to deal with the poor resistance to heat transfer by using plenty of bedclothes, i.e. adding a large resistance in series, but the same approach does not work with noise because earplugs are uncomfortable, fall out in your sleep and have a low resistance at the frequency of taxi-generated noise.  So, the solution is secondary glazing and the best performance is achieved using an acoustic laminate consisting of a polymer sandwiched between two sheets of glass which should be different thickness to avoid resonant effects.  Of course this will also improve the resistance to heat transfer which will be advantageous in winter, but perhaps not in summer…

Financial crisis

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I was in Germany for a progress meeting of a research project last week.  There was talk in the coffee breaks about the financial crisis in Cyprus.  There seemed to be recognition amongst the Germans present that Germany has to assist the Cypriots and other EU member states in financial difficulty.  One reason cited was the Cypriots and other EU nations are consumers of the products of German manufacturing industry including cars, washing machines and pharmaceuticals, and Germany needs customers for its manufactured goods.  Of course, Germany is rich, at least in part, due to its engineering and manufacturing prowess.

In a similar way, during the 19th and early 20th centuries, Britain grew rich from its manufacturing industries.  Some of Britain’s current economic woes derive from its neglect of these wealth-generating industries.  A recent report [http://www.timeshighereducation.co.uk/news/graduates-in-stem-need-to-rise-by-half/2002594.article] suggests that the UK needs to train an extra 40,000 graduates in science and engineering every year just to maintain the status quo in this sector of the economy which is a 50% increase over current levels.  I suspect that the UK is typical of many European countries.

Is it time that so-called ‘bail-out’ and ‘bail-in’ packages for countries included strategies for stimulating and supporting wealth creation industries rather than just rescuing those that have gambled with other people’s wealth?