Tag Archives: Thermodynamics

Puzzles and mysteries

Detail from abstract by Zahrah ReshPuzzles and mysteries are a pair of words that have taken on a whole new meaning for me since reading John Kay’s and Mervyn King’s book called ‘Radical uncertainty: decision-making for an unknowable future‘ during the summer vacation [see ‘Where is AI on the hype curve?‘ on August 12th, 2020]. They describe puzzles as well-defined problems with knowable solutions; whereas mysteries are ill-defined problems, that have no objectively correct solution and are imbued with vagueness and indeterminacy.  I have written before about engineers being creative problems-solvers [see ‘Learning problem-solving skills‘ on October 24th, 2018] which leads to the question of whether we specialise in solving puzzles or mysteries, or perhaps both types of problems.  The problems that I set for students to solve for homework to refine and evaluate their knowledge of thermodynamics [see ‘Problem-solving in thermodynamics‘ on May 6th, 2015] clearly fall into the puzzle category because they are well-defined and there is a worked solution available.  Although for many students these problems might appear to be mysteries, the intention is that with greater knowledge and understanding the mysteries will be transformed into mere puzzles.  It is also true that many real-world mysteries can be transformed into puzzles by research that advances the collective knowledge and understanding of society.  Part of the purpose of an engineering education is to equip students with the skills to make this transformation from mysteries to puzzles.  At an undergraduate level we use problems that are mysteries only to the students so that success is achievable; however, at the post-graduate level we use problems that are perceived as mysteries to both the student and the professor with the intention that the professor can guide the student towards a solution.  Of course, some mysteries are intractable often because we do not know enough to define the problem sufficiently that we can even start to think about possible solutions.  These are tricky to tackle because it is unreasonable to expect a research student to solve them in limited timeframe and it is risky to offer to solve them in exchange for a research grant because you are likely to damage your reputation and prospects of future funding when you fail.  On the other hand, they are what makes research interesting and exciting.

Image: Extract from abstract by Zahrah Resh.

Democratizing education

One motivation for developing Massive Open Online Courses (MOOC) has been to democratize education by giving everyone access to knowledge often presented by leading professors.  It was certainly one reason why I developed and delivered two MOOCs on ‘Energy: Thermodynamics in Everyday Life‘ in 2015/16 and ‘Understanding Super Structures’ in 2017.  The workload involved in supporting thousands of learners around the global is not insignificant and was unsustainable for me so I gave up after running them for a couple of years despite the intangible rewards [see ‘Knowledge spheres‘ on March 9th, 2016 and ‘A liberal engineering education‘ on March 2nd, 2016] . However, I incorporated the MOOC on energy into my undergraduate module on thermodynamics to create a blended approach to learning [see ‘Blended learning environments‘ on November 14th, 2018].  This paid dividends for me when the pandemic forced our campus into lock-down in the middle of semester last March and I already had a large number of bite-sized activities available online for our students.  Most universities have had to move their teaching online due to the pandemic; but not all students are able to access the online materials as easily others.  The Booker shortlisted novelist, Tsitsi Dangarembga has reported how one of her neighbours has struggled to access resources recommended to him by lecturers at his college in Bulawayo due to the cost and unreliability of Wi-Fi in Zimbabwe.  She tried to help him by registering him for her hotspot package but, in common with many students, he studies mainly at night when hotspot venues are closed.  The maps shows the global distribution of learners in one of the Energy MOOCs that I delivered and you can see the holes in Africa and South America which, at the time, we thought might be due to a lack of computer and internet access and Dangarembga’s account seems to support this hypothesis.  So, we designed our second MOOC on Structures to be accessible via a mobile phone by using fewer videos and more audio clips that could be quickly downloaded and listened to offline.  Unfortunately, we ran out of resources to complete the research on whether it was accessed more successfully in those grey areas on the map; however, the audio recordings were unpopular with the more traditional audience in the USA and UK who gave us immediate and vocal feedback!

Source:

Tsitsi Dangarembga, Protest and prizes, FT Weekend, 26/27 September 2020.

Patterson EA, Using everyday engineering examples to engage learners on a massive open online courseInternational Journal of Mechanical Engineering Education, p.0306419018818551

 

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