Weld residual stresses near the bimetallic interface in clad RPV steel: A comparison between deep-hole drilling and neutron diffraction data

The inner surface of ferritic steel reactor pressure vessels (RPV) is clad with strip welded austenitic stainless steel primarily to increase the long-term corrosion resistance of the ferritic vessel. The strip welding process used in the cladding operation induces significant residual stresses in the clad layer and in the RPV steel substrate, arising both from the thermal cycle and from the very different thermal and mechanical properties of the austenitic clad layer and the ferritic RPV steel. This work measures residual stresses using the deep hole drilling (DHD) and neutron diffraction (ND) techniques and compares residual stress data obtained by the two methods in a stainless clad coupon of A533B Class 2 steel. The results give confidence that both techniques are capable of assessing the trends in residual stresses, and their magnitudes. Significant differences are that the ND data shows greater values of the tensile stress peaks (∼100 MPa) than the DHD data but has a higher systematic error associated with it. The stress peaks are sharper with the ND technique and also differ in spatial position by around 1 mm compared with the DHD technique. © 2014 Elsevier B.V

School-based self-management intervention using theatre to improve asthma control in adolescents: a pilot cluster-randomised controlled trial.

BACKGROUND: Children with poorly controlled asthma have higher rates of unplanned healthcare use and school absences, as well as lower rates of medication adherence and knowledge. They also feel less comfortable using their medication at school, due to social fears and bullying. In this study, this was addressed through two school-based self-management interventions piloted to determine which one to use in a full trial. METHODS: We sought to assess the feasibility and acceptability of two school-based self-management intervention aimed at improving asthma control. Schools in London were randomised to (i) a theatre workshop for the whole year group aimed at raising awareness of asthma in schools, followed by self-management workshops for children (full intervention), (ii) theatre workshop alone (theatre only), or (iii) usual care (controls). Opt-out consent was obtained from parents. The study was a cluster randomised pilot trial, using London schools as the unit of allocation. Our primary aim was to assess the feasibility of delivering a self-management intervention in schools aimed at improving the asthma control test (ACT) score at 6 months. Secondary outcomes included acceptability of the school-based interventions, suitability of the theatre intervention and the full intervention with the self-management workshops, and generation of randomised data to inform future power calculations. Data were analysed by generalised mixed-effect models. RESULTS: The recruitment strategy for this trial was effective. Five schools were randomised to full intervention (189 children), four to theatre only (103 children), and six to controls (83 children). Asthma control test (ACT) score at baseline and 6 months was obtained from 178/358 participating children. Compared with the controls, there were no large differences found in ACT score with the full intervention; knowledge and perception of asthma improved though. GP and hospital visits increased in the full intervention group. Compared with controls, ACT score was unchanged in the theatre only group. CONCLUSION: The asthma self-management intervention trial in schools is feasible and acceptable. The full intervention consisting of both theatre and self-management workshop for asthmatics tended to be better suited to improve outcomes than the theatre intervention on its own. This full intervention should be the one carried forward into a main trial if funding for further research was sought. Further work is needed to understand why there was evidence that unscheduled visits to healthcare professionals increased with the full intervention. TRIAL REGISTRATION: The study was registered on the clinical trials database on 14th May 2018 (ID NCT03536416 )

Controlling unsteady cavity flows using internal structures

We report experimental measurements and preliminary analysis on a series of geometric modifications to a rectangular cavity, aimed at alleviating the severity of the aeroacoustic environment. The cavity had a length-to-depth ratio of 5 and a width-to-depth ratio of 1, and featured a simplified representation of a generic missile on the centre line. The modifications consisted of full width and depth ribs or “collars” with a cutout for the missile. Collars could be fitted at various combinations of locations in the cavity and were either straight (i.e. perpendicular to the cavity centre line), leaned or yawed. The cavity flowfield was characterised by surface pressure measurements along the ceiling. Judging from the available measurements the presence of collars modified the mean pressure distribution, and appeared to reduce the acoustic tones and generally lower the broadband noise

Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO2_2

We present a spectroscopic study that reveals that the metal-insulator transition of strained VO$_2$ thin films may be driven towards a purely electronic transition, which does not rely on the Peierls dimerization, by the application of mechanical strain. Comparison with a moderately strained system, which does involve the lattice, demonstrates the crossover from Peierls- to Mott-like transitions

Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator

The topological crystalline insulator tin telluride is known to host superconductivity when doped with indium (Sn$_{1-x}$In$_{x}$Te), and for low indium contents ($x=0.04$) it is known that the topological surface states are preserved. Here we present the growth, characterization and angle resolved photoemission spectroscopy analysis of samples with much heavier In doping (up to $x\approx0.4$), a regime where the superconducting temperature is increased nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like surface states persist

Maximum entropy deconvolution of resonant inelastic x-ray scattering spectra

Resonant inelastic x-ray scattering (RIXS) has become a powerful tool in the study of the electronic structure of condensed matter. Although the linewidths of many RIXS features are narrow, the experimental broadening can often hamper the identification of spectral features. Here, we show that the Maximum Entropy technique can successfully be applied in the deconvolution of RIXS spectra, improving the interpretation of the loss features without a severe increase in the noise ratio