Orthomodular Lattices Induced by the Concurrency Relation

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Hard ultralight systems by thermal spray deposition of WC-CoCr onto AZ31 magnesium alloy

Magnesium alloys in general, and AZ31 in particular, have huge potential as materials for energy saving and emissions reduction in the transportation of people and goods, because of their low density (about 1.7 g∙cm−3) coupled to good bulk mechanical properties. The main weakness is represented by the alloy surface, prone to corrosion and rather soft. Coatings are therefore mandatory, especially in harsh environments. To obtain AZ31 materials with exceptional surface properties High Velocity Oxygen-Fuel (HVOF) thermal spray was exploited to deposit a WC-CoCr coating with very high surface hardness. Because of the heat sensitivity of magnesium alloys, the influence of torch-substrate kinematics and substrate surface preparation on the surface temperature during deposition, the metallurgical characteristics of AZ31, and the residual stress state of the coated samples were investigated. The overall quality of the coatings was also evaluated by abrasion and electrochemical corrosion resistance tests. Proper adjustment of the torch/substrate standoff distance and torch patterning strategy reduced the surface temperature during deposition by around 100 °C, as measured with an IR pyrometer. This also resulted in a decreased magnitude of the average compressive stress in the coating. At the same time, these adjustments did not impair measurably the performances of the coatings, which, regardless of the deposition conditions, had approximately 1200 HV0.3 hardness, 2–4 μA∙cm−2 corrosion current density in 3.5 wt./vol% NaCl aqueous solution, and 7–8 × 10−4 mm3∙(N∙m)−1 specific wear rate under dry particles' abrasion conditions. Cyclic impact tests also showed that the coatings adhered equally well to grit-blasted or machined surfaces. On the other hand, transverse cracks developed across the coatings during impact tests because of the much higher elastic and plastic deformability of the AZ31 substrate. The avoidance of grit-blasting and the lowered deposition temperatures were also important to prevent anomalous grain growth in the AZ31 substrate

RADICAL MUSEOLOGY_Principi e pratiche di ‘contemporaneità dialogica’

Starting from Claire Bishop’s research, expressed in Radical Museology, this text aims to analyze the curatorial approaches pursued by the directors of the Van Abbemuseum (Eindhoven), the Reina Sofia (Madrid) and the MSUM (Ljubljana). Exploring their relation with the local communities, the text reflects upon the museum’s role in our time.Partendo dalle riflessioni espresse da Claire Bishop in Museologia radicale, il testo esamina alcuni approcci curatoriali intrapresi dal Van Abbemuseum di Eindhoven, dal Reina Sofia di Madrid e dal MSUM di Lubiana. Scopo della ricerca è comprendere l’apporto di queste tre istituzioni sul territorio e quali siano gli interrogativi del museo del futuro