Author Archives: Eann Patterson

Digital twins could put at risk what it means to be human

Detail from abstract by Zahrah ReshI have written in the past about my research on the development and use of digital twins.  A digital twin is a functional representation in a virtual world of a real world entity that is continually updated with data from the real world [see ‘Fourth industrial revolution’ on July 4th, 2018 and also a short video at https://www.youtube.com/watch?v=iVS-AuSjpOQ].  I am working with others on developing an integrated digital nuclear environment from which digital twins of individual power stations could be spawned in parallel with the manufacture of their physical counterparts [see ‘Enabling or disruptive technology for nuclear engineering’ on January 1st, 2015 and ‘Digitally-enabled regulatory environment for fusion power-plants’ on March 20th, 2019].  A couple of months ago, I wrote about the difficulty of capturing tacit knowledge in digital twins, which is knowledge that is generally not expressed but is retained in the minds of experts and is often essential to developing and operating complex engineering systems [see ‘Tacit hurdle to digital twins’ on August 26th, 2020].  The concept of tapping into someone’s mind to extract tacit knowledge brings us close to thinking about human digital twins which so far have been restricted to computational models of various parts of human anatomy and physiology.  The idea of a digital twin of someone’s mind raises a myriad of philosophical and ethical issues.  Whilst the purpose of a digital twin of the mind of an operator of a complex system might be to better predict and understand human-machine interactions, the opportunity to use the digital twin to advance techniques of personalisation will likely be too tempting to ignore.  Personalisation is the tailoring of the digital world to respond to our personal needs, for instance using predictive algorithms to recommend what book you should read next or to suggest purchases to you.  At the moment, personalisation is driven by data derived from the tracks you make in the digital world as you surf the internet, watch videos and make purchases.  However, in the future, those predictive algorithms could be based on reading your mind, or at least its digital twin.  We worry about loss of privacy at the moment, by which we probably mean the collation of vast amounts of data about our lives by unaccountable organisations, and it worries us because of the potential for manipulation of our lives without us being aware it is happening.  Our free will is endangered by such manipulation but it might be lost entirely to a digital twin of our mind.  To quote the philosopher Michael Lynch, you would be handing over ‘privileged access to your mental states’ and to some extent you would no longer be a unique being.  We are long way from possessing the technology to realise a digital twin of human mind but the possibility is on the horizon.

Source: Richard Waters, They’re watching you, FT Weekend, 24/25 October 2020.

Image: Extract from abstract by Zahrah Resh.

Scattering electrons reveal dislocations in material structure

Figure 9 from Yang et al, 2012. Map of plastic strain around the crack tip (0, 0) based on the full width of half the maximum of the discrete Fourier transforms of BSE images, together with thermoelastic stress analysis data (white line) and estimates of the plastic zone size based on approaches of Dugdale's (green line) and Irwin's (blue line; dimensions in millimetres).

Figure 9 from Yang et al, 2012. Map of plastic strain around the crack tip (0, 0) based on the full width of half the maximum of the discrete Fourier transforms of BSE images, together with thermoelastic stress analysis data (white line) and estimates of the plastic zone size based on approaches of Dugdale’s (green line) and Irwin’s (blue line; dimensions in millimetres).

It is almost impossible to manufacture metal components that are flawless.  Every flaw or imperfection in a metallic component is a potential site for the initiation of a crack that could lead to the failure of the component [see ‘Alan Arnold Griffith’ on April 26th, 2017].  Hence, engineers are very interested in understanding the mechanisms of crack initiation and propagation so that these processes can be prevented or, at least, inhibited.  It is relatively easy to achieve these outcomes by not applying loads that would supply the energy to drive failure processes; however, the very purpose of a metal component is often to carry load and hence a compromise must be reached.  The deep understanding of crack initiation and propagation, required for an effective and safe compromise, needs detailed measurements of evolution of the crack and of its advancing front or tip [depending whether you are thinking in three- or two-dimensions].  When a metal is subjected to repeated cycles of loading, then a crack can grow incrementally with each load cycle; and in these conditions a small volume of material, just ahead of the crack and into which the crack is about to grow, has an important role in determining the rate of crack growth.  The sharp geometry of the crack tip causes localisation of the applied load in the material ahead of the crack thus raising the stress sufficiently high to cause permanent deformation in the material on the macroscale.  The region of permanent deformation is known as the crack tip plastic zone.  The permanent deformation induces disruptions in the regular packing of the metal atoms or crystal lattice, which are known as dislocations and continued cyclic loading causes the dislocations to move and congregate around the crack tip.  Ultimately, dislocations combine to form voids in the material and then voids coalesce to form the next extension of the crack.  In reality, it is an oversimplification to refer to a crack tip because there is a continuous transition from a definite crack to definitely no crack via a network of loosely connected voids, unconnected voids, aggregated dislocations almost forming a void, to a progressively more dispersed crowd of dislocations and finally virgin or undamaged material.  If you know where to look on a polished metal surface then you could probably see a crack about 1 mm in length and, with aid of an optical microscope, you could probably see the larger voids forming in the material ahead of the crack especially when a load is applied to open the crack.  However, dislocations are very small, of the order tens of nanometres in steel, and hence not visible in an optical microscope because they are smaller than the wavelength of light.  When dislocations congregate in the plastic zone ahead of the crack, they disturb the surface of the metal and causing a change its texture which can be detected in the pattern produced by electrons bouncing off the surface.  At Michigan State University about ten years ago, using backscattered electron (BSE) images produced in a scanning electron microscope (SEM), we demonstrated that the change in texture could be measured and quantified by evaluating the frequency content of the images using a discrete Fourier transform (DFT).  We collected 225 square images arranged in a chessboard pattern covering a 2.8 mm by 2.8 mm square around a 5 mm long crack in a titanium specimen which allowed us to map the plastic zone associated with the crack tip (figure 9 from Yang et al, 2012).  The length of the side of each image was 115 microns and 345 pixels so that we had 3 pixels per micron which was sufficient to resolve the texture changes in the metal surface due to dislocation density.  The images are from our paper published in the Proceedings of the Royal Society and the one below (figure 4 from Yang et al, 2012) shows four BSE images along the top at increasing distances from the crack tip moving from left to right.  The middle row shows the corresponding results from the discrete Fourier transform that illustrate the decreasing frequency content of the images moving from left to right, i.e. with distance from the crack.  The graphs in the bottom row show the profile through the centre of the DFTs.  The grain structure in the metal can be seen in the BSE images and looks like crazy paving on a garden path or patio.  Each grain has a particular and continuous crystal lattice orientation which causes the electrons to scatter differently from it compared to its neighbour.  We have used the technique to verify measurements of the extent of the crack tip plastic zone made using thermoelastic stress analysis (TSA) and then used TSA to study ‘Crack tip plasticity in reactor steels’ [see post on March 13th, 2019].

Figure 4 from Yang et al, 2012. (a) Backscattered electron images at increasing distance from crack from left to right; (b) their corresponding discrete Fourier transforms (DFTs) and (c) a horizontal line profile across the centre of each DFT.

Figure 4 from Yang et al, 2012. (a) Backscattered electron images at increasing distance from crack from left to right; (b) their corresponding discrete Fourier transforms (DFTs) and (c) a horizontal line profile across the centre of each DFT.

Reference: Yang, Y., Crimp, M., Tomlinson, R.A., Patterson, E.A., 2012, Quantitative measurement of plastic strain field at a fatigue crack tip, Proc. R. Soc. A., 468(2144):2399-2415.

My Engineering Day

Photograph of roof tops and chimneys in Liverpool.Today is ‘This is Engineering’ day organised by the Royal Academy of Engineering to showcase what engineers and engineering really look like, celebrate our impact on the world and shift public perception of engineering towards an appreciation that engineers are a varied and diverse group of people who are critical to solving societal challenges.  You can find out more at https://www.raeng.org.uk/events/online-events/this-is-engineering-day-2020.  I have decided to contribute to ‘This is Engineering’ day by describing what I do on a typical working day as an engineer. 

Last Wednesday was like many other working days during the pandemic.  I got up about 7am went downstairs for breakfast in our kitchen and then climbed back upstairs to my home-office in the attic of our house in Liverpool [see ‘Virtual ascent of Moel Famau’ on April 8th, 2020].  I am lucky in that my home-office is quite separate from the living space in our house and it has a great view over the rooftops.  I arrived there at about 7.45am, opened my laptop, deleted the junk email, and dealt with the emails that were urgent, interesting or could be replied to quickly.  At around 8am, I closed my email and settled down to write the first draft of a proposal for funding to support our research on digital twins [see ‘Tacit hurdle to digital twins’ on August 26th, 2020].  I had organised a meeting earlier in the week with a group of collaborators and now I had the task of converting the ideas from our discussion into a coherent programme of research.  Ninety caffeine-fuelled minutes later, I had to stop for a Google Meet call with a collaborator at Airbus in Toulouse during which we agreed the wording on a statement about the impact our recent research efforts.  At 10am I joined a Skype call for a progress review with a PhD student on our dual PhD programme with National Tsing Hua University in Taiwan, so we were joined by his supervisor in Taiwan where it was 6pm [see ‘Citizens of the World’ on November 27th, 2019].  The PhD student presented some very interesting results on evaluating the waviness of fibres in carbon-fibre composite materials using ultrasound measurements which he had performed in our laboratory in Liverpool.  Despite the local lockdown in Liverpool due to the pandemic, research laboratories on our campus are open and operating at reduced occupancy to allow social distancing.

After the PhD progress meeting, I had a catch-up session with my personal assistant to discuss my schedule for the next couple of weeks before joining a MS-Teams meeting with a couple of colleagues to discuss the implications of our current work on computational modelling and possible future directions.  The remaining hour up to my lunch break was occupied by a conference call with a university in India with whom we are exploring a potential partnership.  I participated in my capacity as Dean of the School of Engineering and joined about twenty colleagues from both institutions discussing possible areas of collaboration in both research and teaching.  Then it was back downstairs for a half-hour lunch break in the kitchen. 

Following lunch, I continued in my role as Dean with a half-hour meeting with Early Career Academics in the School of Engineering followed by internal interviews for the directorship of one of our postgraduate research programmes.  At 3.30pm, I was able to switch back to being a researcher and meet with a collaborator to discuss the prospects for extending our work on tracking synthetic nanoparticles into monitoring the motion of biological entities such as viruses and bacteria [see ‘Modelling from the cell through the individual to the host population’ on May 5th 2020].  Finally, as usual, I spent the last two to three hours of my working day replying to emails, following up on the day’s meetings and preparing for the following day.  One email was a request for help from one of my PhD students working in the laboratory who needed a piece of equipment that had been stored in my office for safekeeping.  So, I made the ten-minute walk to campus to get it for her which gave me the opportunity to talk face-to-face with one of the post-doctoral researchers in my group who is working on the DIMES project [see ‘Condition-monitoring using infra imaging‘ on June 17th, 2020].  After dinner, my wife and I walked down to the Albert Dock and along the river front to Princes Dock and back up to our house.

So that was my Engineering Day last Wednesday!

 

Logos of Clean Sky 2 and EUThe DIMES project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 820951.  The opinions expressed in this blog post reflect only the author’s view and the Clean Sky 2 Joint Undertaking is not responsible for any use that may be made of the information it contains.

Lacking creativity

detail tl from abstract painting by Zahrah RI feel that I am moving to the next level of experience with online meetings but I am unsure that it will address the slow down in productivity and a loss of creativity being reported by most leaders of research groups to whom I have spoken recently.  About a month ago, we organised an ‘Away Day’ for all staff in the School of Engineering with plenary presentations, breakout groups and a Q&A session.  Of course, the restrictions induced by the pandemic meant that we were only ‘away’ in the sense of putting aside our usual work routine and it only lasted for half a day because we felt a whole day in an online conference would be counter productive; nevertheless, the feedback was positive from the slightly more than one hundred staff who participated.  On a smaller scale, we have experimented with randomly allocating members of my research team to breakout sessions during research group meetings in an attempt to give everyone a chance to contribute and to stimulate those serendipitous conversations that lead to breakthroughs, or least alternative solutions to explore.  We have also invited external speakers to join our group meetings – last month we had a talk from a researcher in Canada.  We are trying to recreate the environment in which new ideas bubble to the surface during casual conversations at conferences or visits to laboratories; however, I doubt we are succeeding.  The importance of those conversations to creativity and innovation in science is highlighted by the story of how Emmanuelle Charpentier and Jennifer Doudna met for the first time at a conference in Puerto Rico.   While wandering around San Juan on a warm Caribbean evening in 2011 discussing the way bacteria protect themselves against viruses by chopping up the DNA of the virus, they realised that it could be turned into molecular scissors for cutting and editing the genes of any living creature.  They went home after the conference to their labs in Umea University, Sweden and UC Berkeley respectively and collaborated round the clock to implement their idea for which they won this year’s Nobel Prize for Chemistry.  Maybe the story is apocryphal; however, based on my own experience of conversations on the fringes of scientific meetings, they are more productive than the meeting itself and their loss is a significant casualty of the COVID-19 pandemic.  There are people who point to the reduction in the carbon footprint of science research caused by the cancellation of conferences and who argue that, in order to contribute to UN Goals for Sustainable Development, we should not return to gatherings of researchers in locations around the world.  I agree that we should consider our carbon footprint more carefully when once again we can travel to scientific meetings; however, I think the innovations required to achieve the UN Goals will emerge very slowly, or perhaps not all, if researchers are limited to meeting online only.

Source:

Clive Cookson, A dynamic Nobel duo with natural chemistry, FT Weekend, 10/11 October 2020.

Image: Extract from abstract by Zahrah Resh.