Tag Archives: second law

What a waste

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20120609_wom915Einstein’s famous equation, E=mc², does not influence everyday interactions of energy, E and mass, m.  The speed of light, c is 299 792 458 m/s which is very big number and implies a huge amount of energy is required to create a small amount of mass.  This means that energy and mass are independently conserved.  For energy, this is the first law of thermodynamics while the law of conservation of mass is usually attributed to Antoine Lavoisier.  On a planetary scale, the conservation of mass implies that we can assume that the quantity of matter is constant.  Can we apply the second law of thermodynamics to matter as well as energy?  One interpretaton of the second law is that Gibbs energy, or the energy available to do useful work, must decrease in all real processes.   This also applies when matter moves through our economic system.  For instance, we must do work to convert mineral ores into useful products which gradually degrade through use and natural processes, such as corrosion, until they become scrap and we must expend more resources to recycle them and make them useful again.  The sun provides us with a steady supply of useful energy, so that in energy terms planet Earth can be considered an open system with energy flows in and out.  Conversely in mass terms, planet Earth is effectively a closed system with negligible mass flow in or out, so that we do not have a steady supply of new matter from which to manufacture goods.  However, most of us behave with open-world mindset and throw away matter (goods) that are no longer useful to us when we should be repairing and recycling [see my post entitled ‘Old is beautiful‘ on May 1st 2013].  Maybe we can’t reach the zero-waste status aimed at by people like Bea Johnson, but most of us could do better than the 2.2 kg of solid waste produced each day by each of us in OECD countries. That’s 2.1 tonnes per year for an average OECD household (2.63 people)!

Sources:

The New Sustainable Frontier – principles of sustainable development, GSA Office of Governmentwide Policy, September 2009.

Daniel Hoornweq & Perinaz Bhada-Tata, What a Waste: A Global Review of Solid Waste Management, World Bank No.15, 2012.

http://www.economist.com/blogs/graphicdetail/2012/06/daily-chart-3

No closed systems in nature

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WP_20150722_008 (2)While I was away on vacation last month, WordPress sent an email congratulating me on the third anniversary of the start of this blog.  This stimulated me to look at the statistics on the most frequently read, or at least viewed, of the approximately 160 postings that I have written.  Top of the list is an early posting which asks the question ‘Are there any closed systems in nature?’ (see post entitled ‘Closed systems in Nature?’ on December 21st, 2012).  Since this question has generated more interest than any of my subsequent postings, it seems appropriate, after 30 months, to attempt an answer.

Alexander Bogdanov (1873-1928), and independently Karl Ludwig von Bertalanffy (1901-1972), recognized that all living systems are open systems in the thermodynamic sense, which operate far-from equilibrium and require a continual flux of matter and energy to sustain life.  By contrast, closed thermodynamic systems tend to settle into a state of equilibrium, i.e. with no differences in energy, no chemical reactions in progress and no unbalanced forces.

The cybernetist, William Ross Ashby (1903-1972) suggested that living systems are energetically open but operationally closed, i.e. closed to information and control.  In other words, a cell, or any other living organism, needs no information from the environment to be itself. All the information for a bee to be a bee is contained inside a bee (for more on the bee theme see ‘Entropy management for bees and flights‘ on November 5th, 2014 and ‘Fields of flowers’ on July 8th, 2015).  These concepts, of being energetically open and operationally closed, form the essence of the characteristics of biological life as described by Capra and Luisi, whom I have loosely quoted in the previous sentence.

So, to answer my original question, there are no closed living systems in nature.  We can take this a step further: in 1927  Charles Elton defined an ecosystem in terms of the flow of energy and matter from one organism to another. Consequently, the only waste generated by an ecosystem as a whole is the entropy associated with respiration, which allows the system to satisfy the second law of thermodynamics, and the waste is replaced with energy from the sun through photosynthesis.  The sum of all ecosystems is the biosphere.  So, it can be construed that everything on Earth is part of one giant open system – this is essentially the Gaia hypothesis.

Sources:

Gorelik, G., Principal ideas of Bogdanov’s tektology: the universal science of organisation, General Systems, 20:3-13, 1975.

Bertalanffy, L. von, General Systems Theory, New York: Braziller, 1968.

Ashby, W.R., Design for a Brain, New York: Wiley, 1952.

Capra, F., Luisi, P.L., The Systems View of Life – A unifying vision, Cambridge: Cambridge University Press, 2014.

Elton, C.S, Animal Ecology, London: Sidgwick & Jackson, 1927 (reprinted 2001, University of Chicago Press).

Lovelock, J., Gaia, Oxford: Oxford University Press, 1979.

 

 

Dream machine

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Painting by Katy Gibson

Painting by Katy Gibson

A machine that can do work indefinitely without any external input of energy.  It would solve the world’s energy problems, eliminate global warming and make the inventor very rich.  There have been so many attempts to design such a machine that a classification system has been established.  My machine, that does work indefinitely with no energy input, would be a perpetual motion machine of the first type because energy is not conserved – a contradiction of the first law of thermodynamics.  The second type contravene the second law of thermodynamics, usually by spontaneously converting heat into work, and the third type eliminates friction and, or other dissipative forces.

I said ‘my machine’ in the sense that I have an on-going sporadic correspondence with the inventor of a machine that is claimed to produce ‘power above the primary power that drives it’.  It is an epistemic impossibility, which means that it cannot exist within our current understanding of the real world.  In other words, if a perpetual motion machine was to be proven to exist then the laws of thermodynamics would have to be rewritten.  This would probably lead to an invitation to Stockholm to collect a Nobel prize.

Such arguments make no difference to inventors of perpetual motion machines.  Many appear to start from the premise that the laws of thermodynamics have not been proven and hence they must not be universally applicable, i.e. there is space for their invention.  Whereas the laws of thermodynamics form part of our current understanding of the world because no one has demonstrated their falsity despite many attempts over the last two hundred years.  This is consistent with the philosophical ideas introduced by Karl Popper in the middle of the last century.  He proposed that a hypothesis cannot be proven to be correct using observational evidence but its falsity can be demonstrated.

So, inventors need to build and demonstrate their perpetual motion machines in order to falsify the relevant law of science.  At this stage money as an input usually becomes an issue rather than energy!

 

The painting by Katy Gibson is from a series made as part from an art and engine collaboration between Okemos High School Art Program and the Department of Mechanical Engineering at Michigan State University.