Advanced Examination Techniques Applied to the Assessment of Vacuum Pressure Impregnation (VPI) of ITER Correction Coils

The ITER Magnet System includes a set of 18 superconducting correction coils (CC) which are used to compensate the error field modes arising from geometrical deviations caused by manufacturing and assembly tolerances. The turn and ground insulation are electrically insulated with a multi-layer fiberglass polyimide interleaved composite, impregnated with epoxy resin using vacuum pressure impregnation (VPI). Adequate high voltage insulation (5 kV), mechanical strength and rigidity of the winding pack should be achieved after impregnation and curing of the insulation system. VPI is an effective process to avoid defects such dry spots and incomplete wet out. This insulation technology has also been developed since several years for application to large superconducting coils and more recently to ITER CC. It allows the coils to be impregnated without impacting on their functional characteristics. One of the critical challenges associated with the construction of the CC is the qualification of the VPI insulation. Sections issued from representative VPI test samples with real scale side correction Coil (SCC) cross-section have been delivered and characterized at CERN. High resolution micro-optical inspections have been carried out on large areas through digital microscopy. The aim was to identify lack of impregnation, areas of pure resin and void entrapments. The areas near the filling fibre glass rope received special attention. High precision dimensional and geometrical assessments have been performed with the help of image analysis. Compression and pull-out tests have been also carried out. Finally, high-resolution 3D-computed tomography has been applied for a full volumetric inspection of the sections, enabling the reconstruction in three dimensions of the VPI samples and allowing to fully detect, confirm, and image the volume defects already identified by micro-optical observations

Changing patterns of urologic emergency visits and admissions during the COVID-19 pandemic : a retrospective, multicenter, nationwide study

INTRODUCTION: We aimed to examine the change in the number and severity of visits to the emergency departments (EDs) and subsequent admissions for urgent urologic conditions in the early stage of the coronavirus disease 2019 (COVID-19) pandemic in Poland. MATERIAL AND METHODS: We evaluated data from 13 urologic centers in Poland and compared the number of visits to the EDs and subsequent admissions before and after the advent of COVID-19 in 2020, and before and after the escalating national restrictions. Furthermore, data on types of urologic complaints, crucial laboratory parameters, and post-admission procedures were analyzed. RESULTS: In total 1,696 and 2,187 urologic visits (22.45% decrease) and 387 and 439 urologic urgent admissions (11.85% decrease) were reported in given periods in 2020 and 2019, respectively. The year-over-year difference in daily mean visits was clear (36.1 vs. 46.5; p < 0.001). Declines were seen in all complaints but device malfunction. In 2020 daily mean visits and admissions decreased from 40.9 and 9.6 before lockdowns to 30.9 (p < 0.001) and 6.9 (p = 0.001) after severe restrictions, respectively. There was a trend towards more negative laboratory parameter profiles in 2020, with patients who visited the EDs after severe restrictions having twice as high median levels of C-reactive protein (15.39 vs. 7.84, p = 0.03). CONCLUSIONS: The observed declines in ED visits and admissions were apparent with the significant effect of national lockdowns. Our results indicate that some of the patients requiring urgent medical help did not appear at the ED or came later than they would have done before the pandemic, presenting with more severe complaints