Tag Archives: National Tsing Hua University

Professor soars through the landscape

When I was younger, I often had dreams when I was asleep in which I raised my arms and flew effortlessly across the landscape.  I had the opportunity to have a similar experience while awake when I was in Taiwan earlier this year.  I am fairly frequent visitor to Taiwan [see ‘‘Crash’ in Taipei: an engineer’s travelogue‘ on November 19th, 2014 and ‘Citizens of the world‘ on November 27th, 2019].  I often go with colleagues from the UK who have not been before and almost without fail we visit the amazing National Palace Museum.  On my last visit in January [see: ‘Ancient standards‘ on January 29th, 2020] there was an exciting blend of art and technology in an exhibit that allowed the visitor to fly through the landscape of a painting.  I stood in front of a projection of the picture on a large screen and lifted my arms for a moment to allow the computer system to register my position before starting to fly into the picture, tilting left or right to turn, and lowering and raising my arms to slow down or speed up.  Although there was no mask or headphones to wear, the experience was absorbing and realistic.  You can watch me flying with my ‘jetpack’ in this video.

 

Citizens of the world

Last week in Liverpool, we hosted a series of symposia for participants in a dual PhD programme involving the University of Liverpool and National Tsing Hua University, in Taiwan, that has been operating for nearly a decade.  On the first day, we brought together about dozen staff from each university, who had not met before, and asked them to present overviews of their research and explore possible collaborations using as a theme: UN Sustainable Development Goal No.11: Sustainable Cities and Communities.  The expertise of the group included biology, computer science, chemistry, economics, engineering, materials science and physics; so, we had wide-ranging discussions.  On the second and third day, we connected a classroom on each campus using a video conferencing system and the two dozen PhD students in the dual programme presented updates on their research from whichever campus they are currently resident.  Each student has a supervisor in each university and divides their time between the two universities exploiting the expertise and facilities in the two institutions.

The range of topics covered in the student presentations was probably even wider than on the first day; extending from deep neural networks, through nuclear reactor technology, battery design and three-dimensional cell culturing to policy impacts on households.  One student spoke about the beauty of mathematical equations she is working on that describe the propagation of waves in lattice structures; while, another told us about his investigation of the causes of declining fertility rates across the world.  Data from the UN DESA Population Division show that live births per woman in the Americas & Europe have already fallen below the 2.1 required to sustain the population, while it is projected to fall below this level in south-east Asia within the next five years and in the world by 2060.  This made me think that perhaps the Gaia principle, proposed by James Lovelock, is operating and that human population is self-regulating as it interacts with constraints imposed by the Earth though perhaps not in a fashion originally envisaged.

 

Spatial-temporal models of protein structures

For a number of years I have been working on methods for validating computational models of structures [see ‘Model validation‘ on September 18th 2012] using the full potential of measurements made with modern techniques such as digital image correlation [see ‘256 shades of grey‘ on January 22nd 2014] and thermoelastic stress analysis [see ‘Counting photons to measure stress‘ on November 18th 2015].  Usually the focus of our interest is at the macroscale, for example the research on aircraft structures in the MOTIVATE project; however, in a new PhD project with colleagues at the National Tsing Hua University in Taiwan, we are planning to explore using our validation procedures and metrics [1] in structural biology.

The size and timescale of protein-structure thermal fluctuations are essential to the regulation of cellular functions. Measurement techniques such as x-ray crystallography and transmission electron cryomicroscopy (Cryo-EM) provide data on electron density distribution from which protein structures can be deduced using molecular dynamics models. Our aim is to develop our validation metrics to help identify, with a defined level of confidence, the most appropriate structural ensemble for a given set of electron densities. To make the problem more interesting and challenging the structure observed by x-ray crystallography is an average or equilibrium state because a folded protein is constantly in motion undergoing harmonic oscillations, each with different frequencies and amplitude [2].

The PhD project is part of the dual PhD programme of the University of Liverpool and National Tsing Hua University.  Funding is available in form of a fee waiver and contribution to living expenses for four years of study involving significant periods (perferably two years) at each university.  For more information follow this link.

References:

[1] Dvurecenska, K., Graham, S., Patelli, E. & Patterson, E.A., A probabilistic metric for the validation of computational models, Royal Society Open Society, 5:180687, 2018.

[2] Justin Chan, Hong-Rui Lin, Kazuhiro Takemura, Kai-Chun Chang, Yuan-Yu Chang, Yasumasa Joti, Akio Kitao, Lee-Wei Yang. An efficient timer and sizer of protein motions reveals the time-scales of functional dynamics in the ribosome (2018) https://www.biorxiv.org/content/early/2018/08/03/384511.

Image: A diffraction pattern and protein structure from http://xray.bmc.uu.se/xtal/

Press release!

A jumbo jet has about six million parts of which roughly half are fasteners – that’s a lot of holes.

It is very rare for one of my research papers to be included in a press release on its publication.  But that’s what has happened this month as a consequence of a paper being included in the latest series published by the Royal Society.  The contents of the paper are not earth shattering in terms of their consequences for humanity; however, we have resolved a long-standing controversy about why cracks grow from small holes in structures [see post entitled ‘Alan Arnold Griffith‘ on  April 26th, 2017] that are meant to be protected from such events by beneficial residual stresses around the hole.  This is important for aircraft structures since a civilian airliner can have millions of holes that contain rivets and bolts which hold the structure together.

We have used mechanical tests to assess fatigue life, thermoelastic stress analysis to measure stress distributions [see post entitled ‘Counting photons to measure stress‘ on November 18th, 2015], synchrotron x-ray diffraction to evaluate residual stress inside the metal and microscopy to examine failure surfaces [see post entitled ‘Forensic engineering‘ on July 22nd, 2015].  The data from this diverse set of experiments is integrated in the paper to provide a mechanistic explanation of how cracks exploit imperfections in the beneficial residual stress field introduced by the manufacturing process and can be aided in their growth by occasional but modest overloads, which might occur during a difficult landing or take-off.

The success of this research is particularly satisfying because at its heart is a PhD student supported by a dual PhD programme between the University of Liverpool and National Tsing Hua University in Taiwan.  This programme, which supported by the two partner universities, is in its sixth year of operation with a steady state of about two dozen PhD students enrolled, who divide their time between Liverpool, England and Hsinchu, Taiwan.  The synchrotron diffraction measurements were performed, with a colleague from Sheffield Hallam University, at the European Synchrotron Research Facility (ESRF) in Grenoble, France; thus making this a truly international collaboration.

Source:

Amjad K, Asquith D, Patterson EA, Sebastian CM & Wang WC, The interaction of fatigue cracks with a residual stress field using thermoelastic stress analysis and synchrotron x-ray diffraction experiments, R. Soc. Open Sci. 4:171100.