Category Archives: Engineering

Reinforcement ensures long-term structural integrity

Last month when I was in Taiwan [see ‘Ancient Standards‘ on January 29th, 2020] , I visited Kuosheng Nuclear Power Plant which has a pair of boiling water reactors that each generate 986 MWe, or between them about 7% of Taiwan’s electricity.  The power station is approaching the end of its licensed life in around 2023 after being constructed in 1978 and delivering electricity commercially for about 40 years, since the early 1980’s.  There is an excellent exhibition centre at the power station that includes the life-size mock-up of the reinforcement rods in the concrete of the reactors shown in the photograph.  I am used to seeing reinforcing bar, or rebar as it is known, between 6 to 12mm in diameter on building site, but I had never seen any of this diameter (about 40 to 50mm diameter) or in such a dense grid.  On the other hand, we are not building any nuclear power stations in the UK at the moment so there aren’t many opportunities to see closeup the scale of structure required.

Isolated systems in nature?

Is a coconut an isolated thermodynamic system?  This is a question that I have been thinking about this week.  A coconut appears to be impermeable to matter since its milk does not leak out and it might be insulated against heat transfer because its husk is used for insulation in some building products.  If you are wondering why I am pondering such matters, then it is because, once again, I am teaching thermodynamics to our first year students (see ‘Pluralistic Ignorance‘ on May 1st, 2019).  It is a class of more than 200 students and I am using a blended learning environment (post on 14th November 2018) that combines lectures with the units of the massive open online course (MOOC) that I developed some years ago (see ‘Engaging learners on-line‘ on May 25th, 2016).  However, before devotees of MOOCs get excited, I should add that the online course is neither massive nor open because we have restricted it to our university students.  In my first lecture, I talked about the concept of defining the system of interest for thermodynamic analysis by drawing boundaries (see ‘Drawing boundaries‘ on December 19th, 2012).  The choice of the system boundary has a strong influence on the answers we will obtain and the simplicity of the analysis we will need to perform.  For instance, drawing the system boundary around an electric car makes it appear carbon neutral and very efficient but including the fossil fuel power station that provides the electricity reveals substantial carbon emissions and significant reductions in efficiency.  I also talked about different types of system, for example: open systems across whose boundaries both matter and energy can move; closed systems that do not allow matter to flow across their boundaries but allow energy transfers; and, isolated systems that do not permit energy or matter to transfer across their boundaries.  It is difficult to identify closed systems in nature (see ‘Revisiting closed systems in nature‘ on October 5th, 2016); and so, once again I asked the students to suggest candidates but then I started to think about examples of isolated systems.  I suspect that completely isolated systems do not exist; however, some systems can be approximated to the concept and considering them to be so, simplifies their analysis.  However, I am happy to be corrected if anyone can think of one!

Image: https://www.flickr.com/photos/yimhafiz/4031507140 CC BY 2.0

The Stone Raft adrift in the Atlantic Ocean

I spent most of last week at the European Union’s Joint Research Centre in Ispra, Italy.  I have been collaborating with the scientists in  the European Union Reference Laboratory for alternatives to animal testing [EURL ECVAM].  We have been working together on tracking nanoparticles and, more recently, on the validity and credibility of models.  Last week I was there to participate in a workshop on Validation and Acceptance of Artificial Intelligence Models in Health.  I presented our work on the credibility matrix and on a set of factors that we have developed for establishing trust in a model and its predictions. I left the JRC on Friday evening and slipped back in the UK just before she left the Europe Union.  The departure of the UK from Europe reminds me of a novel by José Saramago called ‘The Stone Raft‘ in which the Iberian penisula breaks off from the Europe mainland and drifts around the Atlantic ocean.  The bureaucrats in Europe have to run around dealing with the ensuing disruption while five people in Spain and Portugal are drawn together by surreal events on the stone raft adrift in the ocean.

Inconvenient facts

The latest UN Climate Change Conference in Madrid, which is holding its closing session as I am writing this post, does not appear to have reached any significant conclusions.  Unsurprisingly, vested interests have dominated and there is little agreement on a plan of action to slow down climate change or to mitigate its impact. However, perhaps there is progress because two recent polls imply that 75% of Americans believe humans cause climate change and roughly half say that urgent action is needed.  This is important because the USA has made the largest cumulative contribution to greenhouse gas emissions with 25% of total emissions, followed by the EU-28 at 22% and China at 13%, according to the Our World in Data website.  However, the need for urgent action is being undermined by suggestions that we cannot afford it, or that we will have better technology in the future that will make it easier to act.  However, much of the engineering technology that is needed to remove fossil fuels from our economy is already available.   Of course, the technology will be improved in the future but that is always true because we are continually making technological advances.  We could replace fossil fuels as the energy source for all of our electricity, buildings and heating (31%) and for most of our industry (21%) and transportation (14%) using the technology that is available today and this could eliminate about two-thirds of current global greenhouse gas emissions. The numbers in parentheses are the percentage contributions to global greenhouse gas emissions according to the IPCC. Of course, it would require a massive programme of infrastructure investment; however, if we are serious then the subsidies paid to the oil and gas industry could be redirected toward decarbonising our economies.  According to the IMF, that is approximately $5.2 trillion per year in subsidies, which is about the GDP of Japan.  The science of climate change is well-understood (see for example ‘What happens to emitted carbon‘ and ‘Carbon emissions and surface warming‘) and widely recognised; the engineering technology to mitigate both climate change and its impacts is largely understood and implementation-ready; however, most urgently, we need well-informed public debate about the economic changes required to decarbonise our society.

Sources:

Mark Maslin, The five corrupt pillars of climate change denial, The Conversation, November 28th, 2019.

United Nations Blog, The drive to a conclusion, December 13th, 2019.

Sandra Laville, Top oil firms spending millions lobbying to block climate change policies, says report, The Guardian, March 22nd 2019.

Footnote: The videos ‘What happens to emitted carbon‘ and ‘Carbon emissions and surface warming‘ are part of a series produced by my colleague, Professor Ric Williams at the University of Liverpool.  He has produced a third one: ‘Paris or Bust‘.