News


Half the Alltfedw circuit

Half the Alltfedw circuit

April 2018 - National Resources Wales provide a car park by the Afon Ystwyth near Trawsgoed with two waymarked paths. One of them leads onto Alltfedw, a low ridge to the east of Llanilar and ending fairly abruptly at Trawsgoed. It is mostly covered in forest (Coed Alltfedw). Unfortunately, there had been significant storm damage recently, which hasn't been cleared yet. However, the lower part is accessible with care, while I had to turn round near the summit because the toppled trees were piled up or l... [more] [more external link]  [other news]

Recent beamtime


GISAXS of selective solvent annealed PS-PMMA films

GISAXS of selective solvent annealed PS-PMMA films

Following our in-situ GISAXS experiment at DESY to study the morphological changes to diblock films during selective solvent vapour annealing (SVA), we really needed a few more data points to fill in the parameter space of polymer weight ratios and solvent polarity, at least with ex-situ data of the end product of the SVA process. When Paul Staniec at I22 was looking for a few ex-situ samples to commission his new GISAXS sample environment and beamstop assembly, we had an opportunity to get some of these additional samples measured. [more] [beamtimes]

Teaching materials


ph324 ph338 - Condensed Matter Physics

ph324 ph338 - Condensed Matter Physics

This section of the Condensed Matter module covers the different ways of describing the structure of solids: crystal lattices and coordination polyhedra. Diffraction techniques are used to study crystal structures and their imperfections. In the magnetism section, dia-, para- and ferromagnetic states and the transitions between them are compared. Other collective phenomena in solids such as superconductivity and ferroelectricity are also covered. There is also a practical x-ray diffraction workshop included in this module. [more] [teaching]

Research papers


Dynamic strain propagation in nanoparticulate zirconia refractory

Dynamic strain propagation in nanoparticulate zirconia refractory

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]

Walking in Wales


Boardwalk circuit in Cors Caron

Boardwalk circuit in Cors Caron

Cors Caron from Maes-llyn layby on the B4343 south of Pontrhydfendigaid
A short lunch-time walk to stretch the legs on a crisp winter day. Totally flat, the walk begins at a layby near Maes-llyn farm on the road from Pontrhydfendigaid to Tregaron, where there is a gate leading onto the former railway trackbed (now cycle path) through the raised bog of Cors Caron. After heading south for a kilometre or so, the continuation of the track is gated off (with the cycle path returning to the road) and the boardwalk circuit branches off to the right and into the bog prope... [more]
Elenydd  4.3km  25m  1hrs   [more] [walks]

Other diversions


Southampton's old town and cruise docks

Southampton's old town and cruise docks

The day after the Geograph conference 2014, fellow Geograph-er Basher Eyre took us on a guided tour of Southampton's old town. Starting at the station, we walked past the Civic Centre towards the town walls. After seeing an interesting mural summarising Southampton's history in Hamtun Street and hearing about Southampton's oldest church, St Michael's, we saw a number of preserved buildings such as a mediaeval wine merchant's house and the Duke of Wellington pub, passed by the Mayflower memorial and the offices of the Red Funnel ferry company. The tour ended at the ruins of Holy Rood church (now a war memorial), from where we left for tapas in Oxford Street. After the meal, the group scattered and I continued on my own past Bar Gate and the castle wall down to the City Cruise terminal for a close-up of one of the largest passenger ships ever built. After following the Quay roads and the remnants of the town walls at the southern tip of the old town in bright sunshine, I was chased back to the car by an approaching wall of black cloud. I just made it in time! [slideshow] [more] [other diversions]