Tag Archives: Thermodynamics

Graphite for Very High Temperature Reactors (VHTR)

One of the implications of the second law of thermodynamics is that the thermal efficiency of power stations increases with their operating temperature.  Thus, there is a drive to increase the operating temperature in the next generation of nuclear power stations, known as Generation IV reactors.  In one type of Generation IV reactors, known as the Very High Temperature Reactor (VHTR), graphite is designed to be both the moderator for neutrons and a structural element of the reactor.  Although the probability of damage in an accident is extremely low, it is important to consider the consequences of damage causing the core of the reactor to be exposed to air.  In these circumstances, with the core temperature at about 1600°C, the graphite would be exposed to severe oxidation by the air that could change its material properties and ability to function as a moderator and structural element.  Therefore, in recent research, my research group has been working with colleagues at the UK National Nuclear Laboratory (NNL) and at the National Tsing Hua University (NTHU) in Taiwan to conduct experiments on nuclear graphite over a range of temperatures.  Our recently published article shows that all grades of nuclear graphite show increased rates of oxidation for temperatures above 1200°C.  We found that large filler particles using a pitch-based graphite rather than a petroleum-based graphite gave higher oxidation resistance at these elevated temperatures.  This data is likely to be important in the design and operations of the next generation of nuclear power stations.

The work described above was supported by the NTHU-University of Liverpool Dual PhD Programme [see ‘Citizens of the world‘ on November 27th, 2019] and NNL.  This is the fifth, and for the moment last, in a series of posts on recent work published by my research group.  The others are: ‘Salt increases nanoparticle diffusion‘ on April 22nd, 2020; ‘Spatio-temporal damage maps for composite materials‘ on May 6th, 2020; ‘Thinking out of the box leads to digital image correlation through space‘ on June 24th, 2020; and, ‘Potential dynamic buckling in hypersonic vehicle skin‘ on July 1st, 2020.

The image is figure 5: SEM micrographs of the surface of petroleum-based IG-110 graphite samples oxidized at various temperatures from Lo IH, Tzelepi A, Patterson EA, Yeh TK. A study of the relationship between microstructure and oxidation effects in nuclear graphite at very high temperatures.  J. Nuclear Materials. 501:361-70, 2018.

Source:

Lo I-H, Yeh T-K, Patterson EA & Tzelepi A, Comparison of oxidation behaviour of nuclear graphite grades at very high temperatures, J. Nuclear Materials, 532:152054, 2020.

Thermodynamics labs as homework

Many of my academic colleagues are thinking about modifying their undergraduate teaching for next academic year so that they are more resilient to coronavirus.  Laboratory classes present particular challenges when access and density of occupation are restricted.  However, if the purpose of laboratory classes is to allow students to experience phenomena, to enhance understanding, to develop intuition and to acquire skills in using equipment, making measurements and analysing data, then I believe this can achieved using practical exercises for homework.  I created practical exercises, that can be performed in a kitchen at home, as part of a Massive Open Online Course (MOOC) about thermodynamics [See ‘Engaging learners on-line‘ on May 25th, 2016].  I have used the same exercises as part of my first year undergraduate module on thermodynamics for the past four years with similar levels of participation to those experienced by my colleagues who run traditional laboratory classes [see ‘Laboratory classes thirty years on‘ on May 15th, 2019].  I have had a number of enquiries from colleagues in other universities about these practical exercises and so I have decided to make the instruction sheets available to all.  Please feel free to use them to support your teaching.

The versions below are from the MOOC entitled ‘Energy: Thermodynamics in Everyday Life‘ and provide information about where to obtain the small amount of equipment needed, and hence are self-contained.  Although the equipment only costs about £20, at the University of Liverpool, we lend our students a small bag of equipment containing a measuring beaker, a digital thermometer, a plug-in power meter and a plumber’s manometer.  I also use a slightly different version of these instructions sheets that provide information about ‘lab’ reports that students must submit as part of their coursework.

I reported on the initial introduction of blended learning and these practical exercises in Patterson EA, 2019, Using everyday examples to engage learners on a massive open online course, IJ Mechanical Engineering Education, 0306419018818551.

Instruction sheets for thermodynamics practical exercises as homework:

Energy balance using the first law of thermodynamics | Efficiency of a kettle

Ideal gas behaviour | Estimating the value of absolute zero

Overall heat transfer coefficient | Heat losses from a coffee cup & glass

 

 

Walking and reading during a staycation

I am on vacation this week though, due to the restrictions on our movement imposed to prevent the spread of the coronavirus, it will a be staycation in our house.  We usually go to the Lake District at this time of year to walk and read; so, I might make another virtual expedition [see: ‘Virtual ascent of Moel Famau’ on April 8th, 2020], perhaps to climb Stickle Pike and Great Stickle this time.  I was asked recently about books I would recommend prospective science and engineering students to read in preparation for to going to university.  It is not the first time that I have been asked the question.  This time I thought I should respond via this blog since the disruption brought about by the pandemic probably means that many prospective students will have more time and less preparation prior to starting their university course.  So, here are six books that are all available as ebooks, and might be of interest to anyone who is staying home to counter the spread of coronavirus and has time to fill:

[1] It is hard to find good novels either written by an engineer or about engineering [see ‘Engineering novelist‘ on August 5th, 2015]; however, Nevil Shute’s novel ‘Trustee from the toolroom‘ [Penguin Books, 1960] satisfies all of these criteria.

I have more than 40 years experience of engineering science so I am not the best person to ask about books that will appeal to young people just starting their journey in the field; however two books that have been popular recently are: [2] ‘Storm in a teacup: the physics of everyday life‘ by Helen Czerski [Penguin Books, 2016] and [3] ‘Think like an engineer‘ by Guru Madhavan [One World Publications, 2016]

Regular readers of this blog might have spotted some of my favourite science books in the lists of sources at the end of posts. Perhaps my top three at the moment are:

[4] Max Tegmark, Our Mathematical Universe, Penguin Books Ltd, 2014. [see: ‘Converting wealth into knowledge and back to wealth‘ on January 6th, 2016; ‘Trees are made of air‘ on April 1st, 2015; ‘Is the Earth a closed system? Does it matter?‘ on December 10th, 2014 & ‘Tidal energy‘ on September 17th, 2014]

[5] Susan Greenfield, A Day in the Life of the Brain, London: Allen Lane, 2016 [see: ‘Digital hive mind‘ on November 30th, 2016; ‘Gone walking‘ on April 19th, 2017 & ‘Walking through exams‘ on May 17th, 2017].

[6] Carlo Rovelli, The Order of Time, Penguin, 2019 [see: ‘We inhabit time as fish inhabit water’ on July 24th, 2019 and ‘Only the name of the airport changes‘ on June 12th, 2019].

Of course, I should not omit the books that I ask students to read for my own first year module in thermodynamics:

Peter Atkins, A very short introduction to thermodynamics, Oxford: OUP, 2010.

Manuel Delanda ‘Philosophy and Simulation: The Emergence of Synthetic Reason‘, London: Continuum Int. Pub. Group, 2011 [see: ‘More violent storms‘ on March 1st, 2017; ‘Emergent properties‘ on September 16th, 2015 & ‘Emerging inequality‘ on March 5th, 2014].

 

 

 

Do you believe in an afterlife?

‘I believe that energy can’t be destroyed, it can only be changed from one form to another.  There’s more to life than we can conceive of.’ The quote is from the singer and songwriter, Corinne Bailey Rae’s answer to the question: do you believe in an afterlife? [see Inventory in the FT Magazine, October 26/27 2019].  However, the first part of her answer is the first law of thermodynamics while the second part resonates with Erwin Schrödinger’s view on life and consciousness [see ‘Digital hive mind‘ on November 30th, 2016]. The garden writer and broadcaster, Monty Don gave a similar answer to the same question: ‘Absolutely.  I believe that the energy lives on and is connected to place.  I do have this idea of re-joining all of my past dogs and family on a summer’s day, like a Stanley Spencer painting.’ [see Inventory in the FT Magazine, January 18/19 2020].  The boundary between energy and mass is blurry because matter is constructed from atoms and atoms from sub-atomic particles, such as electrons that can behave as particles or waves of energy [see ‘More uncertainty about matter and energy‘ on August 3rd 2016].  Hence, the concept that after death our body reverts to a cloud of energy as the complex molecules of our anatomy are broken down into elemental particles is completely consistent with modern physics.  However, I suspect Rae and Don were going further and suggesting that our consciousness lives on in some form. Perhaps through some kind of unified mind that Schrödinger thought might exist as a consequence of our individual minds networking together to create emergent behaviour.  Schrödinger found it utterly impossible to form an idea about how this might happen and it seems unlikely that an individual mind could ever do so; however, perhaps the more percipient amongst us occasionally gets a hint of the existence of something beyond our individual consciousness.

Reference: Erwin Schrodinger, What is life? with Mind and Matter and Autobiographical Sketches, Cambridge University Press, 1992.

Image: ‘Sunflower and dog worship’ by Stanley Spencer, 1937 @ https://www.bbc.co.uk/news/entertainment-arts-13789029