Design optimization of RF lines in vacuum environment for the MITICA experiment

This contribution regards the Radio Frequency (RF) transmission line of the Megavolt ITER Injector and Concept Advancement (MITICA) experiment. The original design considered copper coaxial lines of 1″ 5/8, but thermal simulations under operating conditions showed maximum temperatures of the lines at regime not compatible with the prescription of the component manufacturer. Hence, an optimization of the design was necessary. Enhancing thermal radiation and increasing the conductor size were considered for design optimization: thermal analyses were carried out to calculate the temperature of MITICA RF lines during operation, as a function of the emissivity value and of other geometrical parameters. Five coating products to increase the conductor surface emissivity were tested, measuring the outgassing behavior of the selected products and the obtained emissivity values

Effect of Mo content on the microstructure and mechanical properties of CoCrFeNiMox HEA coatings deposited by high power impulse magnetron sputtering

In this work, CoCrFeNiMox high entropy alloy (HEA) films were deposited by High Power Impulse Magnetron Sputtering (HiPIMS) using pure Mo and equiatomic CoCrFeNi targets. The effect of Mo content on the microstructure, residual stress state, and mechanical properties of the films was investigated in the range of 0–20 at.%. All films exhibited a columnar growth morphology and a high density of planar defects. Increasing the Mo content promoted the formation of a fine-grained structure and induced the transformation from a single face-centered cubic (FCC) phase to a mixture of FCC and body-centered cubic (BCC) phases. All produced films displayed a compressive residual stress state regardless of the Mo concentration. In terms of mechanical properties, the hardness of the films increased with increasing Mo content due to solid solution and grain boundary strengthening, along with the formation of a hard BCC phase. On the other hand, the elastic modulus decreased, likely due to the formation of an amorphous phase at higher Mo concentrations

Forget Perón, conquer the market, create a national style: the different "meanings" of Buenos Aires National Library

Buenos Aires National Library (1962-1991) by Clorindo Testa, Francisco Bullrich and Alicia Cazzaniga can be observed by different perspectives. Many of them are in some way related with the idea of Nation and with governmental politics. The building represents an important step in Testa’s creative trajectory. Together with the almost contemporaneous headquarters of the Bank of London and South America, this project is a masterpiece of his concrete architecture of the 1960s, abundant of metaphors, allusions, trespasses and irony and definitely released from all suspicions of Corbusianism. But the competition for the National Library is probably no less interesting than the building itself. Its history could be considered as the history of two strategies. On one side the competition was supposed to provide “the answer to the ones who doubt about our concern for the spiritual future of the Argentineans”, as Culture Secretary Luis Mc Kay said announcing it, and to still all doubts about its liking to Peronist voters (which support has been decisive in 1958 elections). On the other side, architects strongly encouraged the use of competitions as system to assign the works trying to exclude potential competitors, as engineers. Competitions were presented as the most adequate mean to reach works capable of expressing the mission of the new “democratic” institutions born after Perón’s fall. A parallel discourse showed the freedom assured to designers by this system as an essential condition to reach finally the national architecture pursued in vain during the 1940s and the 1950s. Francisco Bullrich, by his writings in the journal Summa and most of all by his book La arquitectura argentina contemporánea (1963), was possibly the main partisan of this thesis, presenting the project for the National library as a promising example