Month: March 2013

Financial crisis

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?

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Born in a barn

108-0858_IMGIn my previous post [Traffic hold-ups, 13th March 2013] the application of Kirchhoff’s Law to the flow of electrons, water and traffic was discussed.  In this context, electrical current or electrons were conceived as flowing.  Instead, electrical current can be considered as electrical energy being transferred across a potential difference, or voltage.  When this terminology is used, then it is only a short step to extend the use of Kirchhoff’s law to consider the combined effect of multiple resistance to other forms of energy transfer, such as heat transfer.  Heat transfer occurs across a temperature difference, from hot to cold, and some materials offer more resistance than others, e.g. wood compared to glass.  Kirchhoff’s law can be used to calculate the total resistance to heat transfer of complex structure such as a house wall that some components in series, e.g. layers of brick, insulation and plasterboard, and some in parallel, e.g. doors and windows.  This information is important in designing a house to achieve minimum energy consumption and to specify the heating and cooling systems required.  Note that the inverse form of Kirchhoff’s Law means that the low resistance to heat transfer of a door or window dominates the heat transfer characteristics of a well-insulated structure.  Of course, the extreme case is when you leave the door open and on a cold day someone shouts at you: ‘Were you born in a barn?’.

Traffic hold-ups

107-0722_IMGGustav Kirchhoff graduated from the University of Konigsberg in 1847 and married his professor’s daughter.  Many people are familiar with his name from studying electrical circuits at school.  His circuit law is an extension of the law of conservation of energy and governs how to combine the effect of multiple electrical resistors.  When resistors are connected in series, i.e. like barges towed by a tug one behind the other, then the value of the resistances can be added together to give a total resistance for the set of resistors.  So, three resistors of 2, 4 and 8 ohms connected in series provide a total resistance of 14 ohms.

However, when resistors are connected in parallel, i.e. like barges strapped alongside the tug, then the calculation of the combined resistance is a little more involved.  The inverse or reciprocal of each resistance must be added together and then the inverse taken of the sum.  So, three resistors of 2, 4 and 8 ohms connected in parallel provide a total resistance of 8/7 ohms [=1/(0.5+0.25+0.125)].

In a parallel circuit, the electrons have a choice about which resistance to flow through.  The same idea can be extend to the resistance to flow in water pipes and to traffic flow.  For traffic flow, the effect of road-works and other hold-ups on multiple routes can be modelled.

Two Cultures

cpsnowThe term ‘Two Cultures’ was coined by Sir Charles Snow more than fifty years ago in his 1959 Rede Lecture to describe the gulf that existed then and persists today between scientists and non-scientists.  He equated not knowing the second law of thermodynamics to never having read anything by Shakespeare.  A number of my posts have referred to the Second Law of Thermodynamics because it explains why engines run and chemical reactions occur but to quote Peter Atkins, it is also ‘the foundation for understanding those most exquisite consequences of chemical reactions – acts of literary, artistic and musical creativity that enhance our culture‘.

Snow, C.P., The Two Cultures: and A Second Look, Cambridge University Press, Cambridge, 1964.

Atkins, P., The Laws of Thermodynamics –  A Very Short Introduction, Oxford University Press, Oxford, 2010.