The effects of temperature and strain rate on the susceptibility of one of the most promising candidate materials for cladding and high temperature components for ADS, Ferritic/Martensitic steel (T91), to liquid metal embrittlement have been investigated in the temperature interval 150-450°C, at strain rates between 1 · 10 À3 s À1 and 1 · 10 À6 s À1 . The effect of the liquid lead bismuth eutectic has been evaluated by comparison between tests in the liquid metal and in Ar with 5% H 2 . Although the untreated T91 material did not undergo liquid metal embrittlement and there was no apparent change in trends of the tensile properties as function of temperature or strain rate due to the liquid metal, the pre-exposed T91, which was exposed to oxygen poor LBE at 450°C for 4000 h and tested at 450°C did show a decrease in total elongation. The total elongation of the untreated T91 specimens in liquid lead bismuth and in H 2 /Ar-gas mixture followed the same dependence on the temperature up to 245°C. At temperatures above 375°C no results are available from testing in controlled gas environment however reference data measured on the same batch of steel in air are used for comparison. Varying the strain rate did not cause any deterioration in the tensile properties of the material in liquid metal compared to those in gas atmosphere. The results are discussed in terms of self-healing mechanism and crack initiation processes.

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A total solar eclipse occurred on 20 March 2015, with a totality path passing mostly above the North Atlantic Ocean, which resulted in a partial solar eclipse over Belgium and large parts of Europe. In anticipation of this event, a dedicated observational campaign was set up at the Belgian Solar-Terrestrial Centre of Excellence (STCE). The objective was to perform high-quality observations of the eclipse and the associated effects on the geospace environment by utilising the advanced space-and ground-based instrumentation available to the STCE in order to further our understanding of these effects, particularly on the ionosphere. The study highlights the crucial importance of taking into account the eclipse geometry when analysing the ionospheric behaviour during eclipses and interpreting the eclipse effects. A detailed review of the eclipse geometry proves that considering the actual obscuration level and solar zenith angle at ionospheric heights is much more important for the analysis than at the commonly referenced Earth's surface or at the plasmaspheric heights. The eclipse occurred during the recovery phase of a strong geomagnetic storm which certainly had an impact on (some of) the ionospheric characteristics and perhaps caused the omission of some ''low-profile'' effects. However, the analysis of the ionosonde measurements, carried out at unprecedented high rates during the eclipse, suggests the occurrence of travelling ionospheric disturbances (TIDs). Also, the high temporal and spatial resolution measurements proved very important in revealing and estimating some finer details of the delay in the ionospheric reaction and the ionospheric disturbances.

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The susceptibility of the ferritic-martensitic steels T91 and EUROFER97 to liquid metal embrittlement (LME) in lead alloys has been examined under various conditions. T91, which is currently the most promising candidate material for the high temperature components of the future accelerator driven system (ADS) was tested in liquid lead bismuth eutectic (LBE), whereas the reduced activation steel, EUROFER97 which is under consideration to be the structural steel for fusion reactors was tested in liquid lead lithium eutectic. These steels, similar in microstructure and mechanical properties in the unirradiated condition were tested for their susceptibility to LME as function of temperature (150-450°C) and strain rate (1 Â 10 À3 -1 Â 10 À6 s À1 ). Also, the influence of pre-exposure and surface stress concentrators was evaluated for both steels in, respectively, liquid PbBi and PbLi environment. To assess the LME effect, results of the tests in liquid metal environment are compared with tests in air or inert gas environment. Although both unirradiated and irradiated smooth ferritic-martensitic steels do not show any or little deterioration of mechanical properties in liquid lead alloy environment compared to their mechanical properties in gas as function of temperature and strain rate, pre-exposure or the presence of surface stress concentrators does lead to a significant decrease in total elongation for certain test conditions depending on the type of liquid metal environment. The results are discussed in terms of wetting enhanced by liquid metal corrosion or crack initiation processes.