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The mathematics of crystallography in senior secondary schooling
(International Union of Crystallography, 2017-12-01) Edwards, AJ; Piltz, RO; Fuentes-Montero, L; Edwards-McKeown, CF
The mathematics required to comprehend much of crystallography is widely taught in the senior years of secondary schooling in many countries, at the same time, there is consternation regarding perceived losses in interest in STEM (Science, Technological, Engineering and Mathematics) subjects, and worse, a failure to engage a significant proportion of young women in these topics in the first instance. In observing the beautiful patterns which result from Laue diffraction experiments we have been encouraged to explore the possibility of employing tools originally developed to analyse experimental patterns[1, 2] as a conduit through which students may be engaged in the exploration of a mathematically based subject. The aesthetically pleasing demonstrations of real-life examples can be shown while the modifications which occur with changing orientation or cell dimensions can be explored. © International Union of Crystallography
Diurnal boundary layer mixing patterns characterised by radon-222 gradient observations at Cabauw
(American Meterological Society, 2008-06-09) Zahorowski, W; Williams, AG; Vermeulen, AT; Chambers, SD; Crawford, J; Sisoutham, O
Gradient measurements of the naturally occurring trace gas radon-222 can be used to construct quantitative measures of mixing and exchange within the lower atmosphere on diurnal timescales, and are beginning to be used in the evaluation of boundary layer mixing schemes in weather and climate models. Radon, a radioactive noble gas with a half-life of 3.8-days, is emitted from terrestrial surfaces at a rate that can be assumed to be uniform and steady on diurnal timescales. Radon's decay rate is optimum for boundary layer mixing studies, as it is negligible in comparison with typical turbulent timescales, but is fast enough to constrain its concentration in the free troposphere to be typically 1-3 orders of magnitude lower than near the surface. These properties combined make radon an excellent tracer for boundary layer vertical mixing studies. Continuous measurements of radon-222 gradients are currently being conducted at two meteorological towers on seasonal to inter-annual timescales. Near-surface gradients (2-50m) are recorded on a 50m tower at Lucas Heights, New South Wales (34.053S, 150.981E), and boundary layer gradients (20-200m) are recorded on the 213m tower at the Cabauw Experimental Site for Atmospheric Research (CESAR) in The Netherlands (51.971N, 4.927E). Here we focus on results from the first year of radon gradient observations at the Cabauw site, which is located 50km inland on a polder in an agricultural region and has a simple orography with surface elevations changing by a few metres at most within a 20 km radius. Two dedicated inlets mounted on the main meteorological tower at 20m and 200m above ground level are providing continuous radon data at hourly time resolution, and meteorological data from the tower is being provided by the Royal Netherlands Meteorological Institute (KNMI). We present a series of examples of radon and corresponding meteorological time series data at two heights on the Cabauw tower at different times of year. The examples illustrate the influence on the radon signal of atmospheric processes occurring on two very different spatio-temporal scales: 1. Synoptic variability, which causes changes in regional fetch (high-radon air from continental regions and low-radon air from oceanic regions) and influences the radon signal at both heights in a similar way; and 2. Diurnal variability, which causes changes in the local vertical mixing within the ABL, leading to a strong pattern of variations in the radon gradient between the 20m and 200m levels. By comparing radon concentrations at 20m and 200m it is thus possible to disentangle influences on these two scales sufficiently to unambiguously characterise and quantify diurnal vertical mixing. The radon concentration gradient proves to be a highly sensitive direct measure of the degree of vertical turbulent mixing in the lower atmosphere. The figure illustrates the effects on the radon signal of the competing influences of suppression of turbulence by nocturnal temperature stratification, on the one hand, and its mechanical generation by low level wind shear on the other. On each of the 5 nights displayed, the temperature gradient signal indicates a moderate-to-strong suppression of vertical turbulent mixing. However, only on the first two nights does this result in a significant radon peak, because over the subsequent period increasing wind shear acts to enhance and deepen the low level mixing.
Neural ray tracing for a neutron triple axis spectrometer
(American Physical Society, 2023-03) Stampfl, APJ
The behaviour of a neutron scattering instrument may be approached both analytically as well as numerically. Traditionally numerical studies entail some form of ray-tracing approach that allows for a realistic and accurate model of the behaviour of an instrument. In-particular resolution and flux are two important parameters that require accurate determination when building an instrument like a triple-axis. The numerical approach produces realistic results albeit often using a skeleton type model of the instrument. Despite the success of a triple-axis configuration where radiation is conditioned in reciprocal and energy space, background signal observed in all spectra measured, is a very important parameter that isn’t easily quantifiable without including the structural and shielding materials that also go into a full working spectrometer. © 2025 American Physical Society The advent of deep learning via simulated neural networks is a significant development that we wish to explore to describe the behaviour of a triple axis spectrometer when thermal neutron radiation passes through it. Neural representations of the solid model and neutron transport are rendered to produce radiation maps S(e,r) at any point along the instrument and in the area surrounding it
Solid-state chemistry and applications: general discussion
(Royal Society of Chemistry (RSC), 2017-10-13) Aakeröy, CB; Alavi, S; Beyeh, NK; Brammer, L; Branca, M; Bryce, DL; Christopherson, JC; Clark, T; Cottrell, SJ; Del Bene, JE; Dichiarante, V; Edwards, AJ; Erdelyi, M; Esterhuysen, C; Fourmigué, M; Friščić, T; Kennepohl, P; Legon, AC; Lloyd, GO; Murray, JS; Mustoe, CL; Pennington, WT; Rosokha, SV; Roy Choudhury, A; Scheiner, S; Szell, PMJ; Taylor, MS; Tsuzuki, S
None available as a discussion
The halogen bond in solution: general discussion
(Royal Society of Chemistry, 2017-09-29) Aakeröy, CB; Beer, PD; Beyeh, NK; Brammer, L; Branca, M; Bryce, DL; Del Bene, JE; Edwards, AJ; Erdelyi, M; Esterhuysen, C; Fourmigué, M; Kennepohl, P; Lee, LM; Mosquera, MEG; Murray, JS; Mustoe, CL; Pennington, WT; Politzer, P; Riley, KE; Rosokha, SV; Scheiner, S; Taylor, MS; Tsuzuki, S; Vargas-Baca, I; Xu, YJ
None available as a discussion.

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