Month: December 2013

Happy Christmas

I am on holiday today and trying to demonstrate to family and friends that engineers have social skills too, contrary to Dilbert’s view on the social skills of engineers, see http://dilbert.com/strips/comic/2013-11-19/

Winter in Okemos, Michigan.

Winter in Okemos, Michigan.

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Hiding in the basement

us highwayWhen we lived in the USA, I remember seeing billboards along the Interstate with messages from FEMA telling us ‘Be Ready’, to prepare, to plan, and to stay informed.  I was never quite sure what we were meant to be ready for since we lived in rural Michigan where we were fortunate not to experience violent weather and to be far from industrial plants that might explode and shower us with chemicals or radiation.  The billboard advertised the FEMA website [www.ready.gov] which contains very little factual information about radiation but does imply you should seek shelter in the basement of tall buildings in the event of a nuclear accident. Some commentators have suggested that the psychological effects arising from fear of nuclear radiation can cause more health issues than the dosage received especially for those not in the immediate vicinity of an incident.  So, knowing more about radiation in advance of an incident would be helpful and might also dispel many of the fears that cause opposition to nuclear energy.

So, does sheltering in a basement offer reasonable protection?  Well, radiation is produced when radioactive materials decay and their atoms release protons and neutrons from their nucleus plus some of the electrons that orbit the nucleus.  The protons and neutrons cluster together to form alpha particles (actually Helium nucleii) that are relatively massive and can stopped by a sheet of paper.  The electrons, known as beta radiation, whizz out at high-speed but can be stopped by a thin sheet of Aluminium.  High-energy photons are also released with the electrons and are known as Gamma radiation, which requires a sheet of lead or a considerable thickness of concrete to stop them.

So sheltering in the basement is a good idea especially if the building above contains a substantial amount of concrete.

Sources:

http://www.ready.gov/nuclear-power-plants

David Ropeik, Fear vs. radiation: The mismatch, in the International New York Times, Tuesday October 22, 2013. http://www.nytimes.com/2013/10/22/opinion/fear-vs-radiation-the-mismatch.html?_r=0

Zen and entropy

Picture1Last weekend I went to a performance of Handel’s Messiah in our local cathedral.  The atmosphere in the vast cathedral was wonderful and for part of the performance I was transformed into a zen-like state by the music.

However, there were quite of lot of disturbances during the performance including some that went beyond the usual coughing and sneezing.  It is interesting that a sneeze in the quiet environment of a cathedral or library causes a large disturbance while the same sneeze in a busy street goes unnoticed.  Of course, it is about the change in the noise level, and as a percentage, the added noise of a sneeze is much greater in the quiet library than the busy street.  Noise is a form of energy that becomes dispersed and dissipated as it propagates and so it is easy to equate it to heat which exhibits the same behaviour.  Heat transfers from hot to cold places while noise propagates from loud to quiet places, and neither does the reverse, which was Clausius’ observation that lead to the Second Law of Thermodynamics.  Clausius also defined change in entropy as the heat transfered divided by the temperature at which it occurs.  So the same heat transfer creates more entropy at low than at high temperatures, just as a sneeze causes more disorder/disruption in a quiet than a loud environment.  We can equate entropy to the level of disorder present in any system or environment.

And the second law of thermodynamics states that the entropy of an isolated system will always increase until it reaches a maximum at equilibrium.

War and peace

The recent negotiations with Iran have brought nuclear weapons back into the forefront of the public’s consciousness, if they ever left it.  This leads to some misplaced sentiments about nuclear energy due to the closely linked history and science of nuclear technology for war and peace.  There is no doubt that nuclear bombs are terrible weapons of mass destruction but so are certain chemical agents and yet there is not the same level of public and political angst about building chemical plants as there is over nuclear power stations.  The civil chemical and nuclear industries are both strictly regulated but the chemical industry has had some horrific accidents, such as at Bhopal, India in 1984 where 8000 people were killed when a pesticide plant leaked toxic gas, or more recently in the US when a fertilizer plant in West, Texas exploded killing 15 people and levelling hundreds of homes.  These incidents are not well-known outside of the engineering industry whereas by contrast the nuclear industry has had a small number of very well-publicized accidents that have killed very few people, or no one in the case of the recent accident at Fukushima.

People will argue that I am ignoring the long-term effects of exposure to radiation so it is appropriate to examine the evidence.  The atomic bomb dropped on Hiroshima killed an estimated 130,000 people, mainly due to the blast rather than radiation, while a long-term study of survivors within 10 kilometres of the explosions has found increased incidents of cancer arising from radiation exposure.  Following the Chernobyl accident in 1986, 240,000 workers were exposed to radiation levels higher than 100 millisieverts and 28 died from acute radiation sickness (ARS) that year.  The World Health Organisation estimates that about 4000 of these workers will die from cancer as a consequence of their radiation exposure about another 9000 amongst the exposed population in Belarus, the Russian Federation and Ukraine.  These are large numbers but represent only about a 1% of the total number of cancer deaths in these populations from other causes, for instance smoking caused about 294,000 deaths in the roughly the same twenty years in Belarus.

It’s time we decoupled the use of nuclear technology in war and peace.  We don’t handicap other technologies used in war and peace with the same indistinguishable associations.  We use fossil fuels to power tanks, jet-fighters and warships and then burn so much of it for peaceful purposes that 1.2 million people died prematurely last year from the pollution it generated [see my post entitled ‘Year of Air: 2013’ on 20th November, 2013].

Sources:

http://news.bbc.co.uk/onthisday/hi/dates/stories/december/3/newsid_2698000/2698709.stm

http://www.huffingtonpost.com/2013/08/01/obama-chemical-plants_n_3688272.html

http://news.bbc.co.uk/onthisday/hi/dates/stories/august/6/newsid_3602000/3602189.stm

http://www.rerf.jp/glossary_e/lss.htm

Little, M., 2009, Cancer and non-cancer effects in Japanese atomic bomb survivors, Journal of Radiological Protection, 29(2A):A43-59. http://iopscience.iop.org/0952-4746/29/2A/S04;jsessionid=7838AA7D498065F13C23094F1D01DBBA.c3

Cardis. E., et al., 2006, Concer consequences of the Chernobyl accident: 20 years on, Journal of Radiological Protection, 26:127-140. http://iopscience.iop.org/0952-4746/26/2/001/pdf/0952-4746_26_2_001.pdf

http://www.ctsu.ox.ac.uk/research/mega-studies/mortality-from-smoking-in-developed-countries-1950-2010/mortality-from-smoking-in-developed-countries-1950-2010/view