September 2015 - Nathan presented a poster on Induced ordering of nanoparticle-loaded diblock copolymer films at the IoP's Physical Aspects of Polymer Science conference at Manchester, showing work from our recent experiment at DESY and related microscopy results. Chris Finlayson, one of our co-authors from Aber, also attended the same meeting with another poster of his own work. [more ] [other news]
The original aim of this experiment was to use proton/deuteron contrast to locate remnants of the solvents used in solvent-vapour annealing in our polymer films. As it turns out, the contrast arising from these small amounts of trapped solvent is insufficient to be detected on a sensible time scale. We therefore switched tack somewhat and varied the solvent from more polar (acetone) to non-polar (hexane) and the substrate temperature during annealing from 21C down to 1C. An initial look at the data suggests that they are in line with our findings using GISAXS during the recent commissioning experiment at I22. [more] [beamtimes]
Third-year lab consists of a project for all physics students. This is usually a year-long effort, although joint students do a shorter version in the second semester only. Students generally work in pairs, although finalists are expected to write an individual report at the end.
A wide range of projects is available to choose from on the website, and we are also happy to consider students' own ideas if they fit with the goals of the module. Please speak to potential supervisors!
Each project is structured into a literature review, project planning, experimental and dissemination phase. Projects can be experimental, observational, theoretical or software development.
Dyma fersiwn Cymraeg y ddogfennaeth prosiect BSc hefyd. [more] [teaching]
Residual and intrinsic strains in granular materials have been studied extensively. However, understanding the dynamic strains that cause these resultant residual strains is key to developing better strain-resistant materials. This investigation demonstrates a method for characterizing dynamic strain propagation in granular materials. The specimen is a zirconia based refractory composed of sol-gel-derived zirconia nanoparticles in a potassium silicate glass binder. In situ synchrotron X-ray powder diffraction in flat-plate geometry is used to characterize the sample structure on timescales of the order of 1ms. A 125W CO2 laser is used to strain the sample with a 25ms pulse length. To compensate for the poor flux on this timescale, a pump-probe method is repeated 1000 times and the resulting data are subsequently re-binned to improve statistics. A Gaussian weighting function is also used to introduce better contrast between strained and unstrained frames. TOPAS Academic is used for fitting with a Le Bail model in batch mode. Lattice parameters and sample height are refined during fitting, along with a Lorentzian line width for extracting microstrain broadening. Microstrains, epsilon, in the range of 1.01% < epsilon < 1.46% are reported on a 1ms timescale. [request reprint] [papers]
Pumlumon Fawr from Nant-y-Moch
A surprise sunny cold spell at the weekend between two miserable, murky November weeks gave an opportunity for a quick ascent of Pumlumon Fawr from Nant-y-Moch reservoir. As the camera battery was playing up, I had to resort to using the phone to take pictures - with reasonable results. Starting from the minor road running up the eastern shore of Nant-y-Moch reservoir, I took the hydro track to Llyn Llygad Rheidol, waded through the stream emerging from its overflow and made my way up toward... [more]
Elenydd 10.2km 430m 3.5hrs [more] [walks]
Google has become sooo clever these days, it even knows better what I want search for than I do myself. At least it thinks it does. Alas, when seeking for a noodle in a haystack, it's not helpful to find zillions of needles instead. Here's a search box that keeps the pesky spell checker in check. [more] [other diversions]