Category Archives: Uncategorized

Change in focus

Decorative image of a painting by Sarah Evans The new academic year is well and truly underway.  It was 2019 when we last welcomed students to campus in person for the start of the academic year.  In my role as Dean, I have been touring lecture theatres trying to speak to and welcome students in all of our taught programmes in the School of Engineering.  It is exciting to see packed lecture theatres full of students eager to listen and learn.  For the first time in a decade, I am not teaching this year so that I can focus on other activities.  I have mixed feelings about giving up teaching.  I taught my first class thirty-six years ago in Mechanics of Solids.  For the last eleven years I have been teaching Thermodynamics to first year students [see, for example ‘From nozzles and diffusers to stars and stripes‘ on March 30th, 2022].  So, teaching has been a substantial part of my working life and its absence will leave a large hole.  I will miss the excitement of standing in front of a class of hundreds of students as well as the rewards of interacting with undergraduate students who are encountering and engaging with a new subject.  One consequence of my change in focus is likely to be a decline in the frequency of blog posts featuring thermodynamics [you can read them all under ‘Thermodynamics’ in Categories], but perhaps that will be a relief to many readers.

Image: Painting by Sarah Evans owned by the author.

On flatness and roughness

Photograph of aircraft carrier in heavy seas for decorative purposes onlyFlatness is a tricky term to define.  Technically, it is the deviation, or lack of deviation, from a plane. However, something that appears flat to human eye often turns out not to be at all flat when looked at closely and measured with a high resolution instrument.  It’s a bit like how the ocean might appear flat and smooth to a passenger sitting comfortably in a window seat of an aeroplane and looking down at the surface of the water below but feels like a roller-coaster to a sailor in a small yacht.  Of course, if the passenger looks at the horizon instead of down at the yacht below then they will realise the surface of the ocean is curved but this is unlikely to be apparent to the sailor who can only see the next line of waves advancing towards them.  Of course, the Earth is not flat and the waves are better described as surface roughness.  Some months ago I wrote about our struggles to build a thin flat metallic plate using additive manufacturing [see ‘If you don’t succeed, try and try again…’ on September 29th, 2021].  At the time, we were building our rectangular plates in landscape orientation and using buttresses to support them during the manufacturing process; however, when we removed the plates from the machine and detached the buttresses they deformed into a dome-shape.  I am pleased to say that our perseverance has paid off and recently we have been much more successful by building our plates orientated in portrait mode, i.e., with the short side of the rectangle horizontal, and using a more sophisticated design of buttresses.  Viewed from the right perspective our recent plates could be considered flat though in reality they deviate from a plane by less than 3% of their in-plane dimensions and also have a surface roughness of several tens of micrometres (that’s the average deviation from the surface).  The funding organisations for our research expect us to publish our results in a peer-reviewed journal that will only accept novel unpublished results so I am not going to say anything more about our flat plates.  Instead let me return to the ocean analogy and try to make you seasick by recalling an earlier career in which I was on duty on the bridge of an aircraft carrier ploughing through seas so rough, or not flat, that waves were breaking over the flight deck and the ship felt like it was still rolling and pitching when we sailed serenely into port some days later.

The current research is funded jointly by the National Science Foundation (NSF) in the USA and the Engineering and Physical Sciences Research Council (EPSRC) in the UK (see Grants on the Web).

Image from

Bringing an end to thermodynamic whoopee

Two weeks ago I used two infographics to illustrate the dominant role of energy use in generating greenhouse gas emissions and the disportionate production of greenhouse gas emission by the rich [see ‘Where we are and what we have‘ on November 24th, 2021].  Energy use is responsible for 73% of global greenhouse gas emissions and 16% of the world’s population are responsible for 38% of global CO2 emissions.  Today’s infographics illustrate the energy flows from source to consumption for the USA (above), UK and Europe (thumbnails below).  In the USA fossil fuels (coal, natural gas and petroleum) are the source of nearly 80% of their energy, in the UK it is a little more than 80% and the chart for Europe is less detailed but the proportion looks similar. COP 26 committed countries to ending ‘support for the international unabated fossil fuel energy sector by the end of 2022’ and recognised ‘investing in unabated fossil-related energy projects increasingly entails both social and economic risks, especially through the form of stranded assets, and has ensuing negative impacts on government revenue, local employment, taxpayers, utility ratepayers and public health.’  However, to reduce our dependency on fossil fuels we need a strategy, a plan of action for a fundamental change in how we power industry, heat our homes and propel our vehicles.  A hydrogen economy requires the production of hydrogen without using fossil fuels, electric cars and electric domestic heating requires our electricity generating capacity to be at least trebled by 2050 in order to hit the net zero target. This scale and speed of  transition to zero-carbon sources is such that it will have to be achieved using an integrated blend of green energy sources, including solar, wind and nuclear energy.  For example, in the UK our current electricity generating capacity is about 76 GW and 1 GW is equivalent to 3.1 million photovoltaic (PV) panels, or 364 utility scale wind turbines [] so trebling capacity from one of these sources alone would imply more than 700 million PV panels, or one wind turbine every square mile.  It is easy to write policies but it is much harder to implement them and make things happen especially when transformational change is required.  We cannot expect things to happen simply because our leaders have signed agreements and made statements.  Now, national plans are required to ween us from our addiction to fossil fuels – it will be difficult but the alternative is that global warming might cause the planet to become uninhabitable for us.  It is time to stop ‘making thermodynamic whoopee with fossil fuels’ to quote Kurt Vonnegut [see ‘And then we discovered thermodynamics‘ on February 3rd, 2016].











Kurt Vonnegut, A Man without a Country, New York: Seven Stories Press, 2005.  He wrote ‘we have now all but destroyed this once salubrious planet as a life-support system in fewer than two hundred years, mainly by making thermodynamic whoopee with fossil fuels’.

US Energy flow chart:

EU Energy flow chart:

UK Energy flow chart:

Switching off and walking in circles

Traditionally in Easter week, I go to the Lake District for a week of hill-walking with my family and a digital detox [see ‘Eternal non-existence‘ on April 24th, 2019 and ‘Gone walking‘ on April 19th, 2017]. For the second year in succession, we have had to cancel our trip due to the national restrictions on movement during the pandemic [see ‘Walking and reading during a staycation‘ on April 15th, 2020]. I am still attempting a digital detox but the walking is restricted to a daily circuit of our local park. While Sefton Park is not on the scale of Central Park in New York or Regent’s Park in London, it is sufficiently large that a walk to it, round its perimeter and home again takes us about two hours. It might not be as strenuous as climbing Stickle Pike but it is better than repeatedly climbing the stairs which was the limit of our exercise last year [see ‘Virtual ascent of Moel Famau‘ on April 8th, 2020].  We might not be allowed to leave our locality but we can switch off all of our devices, do some off-line reading (see ‘Reading offline‘ on March 19th, 2014), slow down, breathe our own air (see ‘Slow down, breathe your own air‘ on December 23rd, 2015) and enjoy the daffodils.