REMOTE PLASMA CHEMICAL VAPOUR DEPOSITION FOR GAS DIFFUSION LAYER AND PROTON EXCHANGE MEMBRANE SYNTHESIS FOR FUEL CELLS

Climate change due to the increase in GHG emissions and energy crisis due to scarcity of fossil fuel availability are an ever growing issue for the planet and countries. The decarbonization and the sustainability of the energy sector is one of the top priority to achieve a resilient system. Hydrogen has been considered for decades to be used as an alternative for fossil fuel and now is the time of development for an hydrogen based economy. Fuel cells are devices that convert the hydrogen chemical energy into electrical energy and is one the main component considered for the hydrogen economy. However, much is yet to be achieved to make their manufacturing as cheap and as efficient as possible. Chemical vapour deposition (CVD) is a technique used to synthesize solid materials from gaseous precursors which has the advantages, over wet chemistry, to reduce wastes of production, to be cheap, to make pure solid materials and to be easily scalable. In this thesis we investigated the possibility to use CVD to produce two major components of fuel cells, namely the gas diffusion layer and the proton exchange membrane. The results were highly promising regarding the elaboration of gas diffusion layers and a CVD prototype was assembled to make the highly complex copolymerization of proton exchange membrane a reality with promising initial results

REGULUS Electric Propulsion Module IoD in UniSat-7 Mission

T4i is a propulsion system company founded in 2014, originated from the Space Propulsion Group of University of Padua, Italy, and active in the market of small satellites. In the last decade T4i has been developing REGULUS, a cutting-edge electric propulsion system for in-space mobility fed with iodine propellant. REGULUS has been specifically designed for Cubesats and micro satellite platforms and it is based on a RF Magnetically Enhanced Plasma (MEP) thruster. Thanks to its standard interfaces it is conceived to be easily “plugged&played” into the satellite, without complex engineering procedures

Le traduire collectif – Propositions théoriques autour d’expériences de traduction collective

Les lignes qui suivent se proposent de questionner théoriquement le traduire collectif, objet théorique peu, voire pas étudié par la recherche universitaire. Nous le ferons en portant notre attention sur les aspects qui marquent un degré de différence et d’éloignement par rapport à la pratique solitaire. Le traduire collectif sera d’abord interrogé dans sa dimension de laboratoire. L’analyse de cet espace nous permettra, dans un deuxième temps, d’explorer les différentes déclinaisons de la dé..

UNISAT-7: A Flexible IOD Platform with Orbital Maneuvering Capabilities

New Space technology for Small Satellites has greatly advanced in the past five years. These progresses shall match with a swift integration and testing phase, to be readily marketable, therefore IOD missions are essential to expedite project outcomes. GAUSS has started working on Small Satellites since 1990s, with its first satellite, UNISAT, launched in 2000. In 2013, UNISAT-5 was the first platform to accomplish in-orbit-release of third-party satellites, with UNISAT-6 following in less than one year. UNISAT-7 is the latest addition to the UNISAT series: a 32kg microsatellite designed and manufactured by GAUSS Srl (a spin-off company of Scuola di Ingegneria Aerospaziale, Sapienza University of Roma), built from scratch thanks to the extensive experience gained with past missions. Launch is scheduled in in Q1 2021. It is the most complex mission ever flown by GAUSS, and it includes several original GAUSS subsystems developed for Earth Observation, sat-to-ground optical links, navigation, power, RF, and Smallsat in-orbit-deployments. All these subsystems are tested in orbit in specific IOD missions. Moreover, UNISAT-7 integrates a precise ADCS solution and a newly developed low-thrust, electric propulsion system named REGULUS, from Italian Company Technology for Propulsion and Innovation (T4i), which will allow the satellite to modify its final orbit, as well as to execute housekeeping maneuvers for drag compensation. REGULUS is a propulsive unit based on MEPT (Magnetically Enhanced Plasma Thruster) technology developed inside the propulsion laboratory of the University of Padua. T4i, born as a Spin-off of the University of Padua, industrialized this technology in order to make it fly. REGULUS is T4i very first product that has ever flown into space. Its envelope is 1.5 U of volume, it is equipped with solid iodine propellant and its main features are a thrust level of 0.55 mN and Isp of 550 s at 50 W of input power, and wet mass of 2.5 kg at 3000 Ns of Itot. REGULUS is designed to serve nanosatellite platforms from 6U to 24U and CubeSat carriers. The integration took place in GAUSS white chamber in Rome in late 2020 and the launch is scheduled in March 2021 from Baikonur as a secondary payload of Soyuz-2-1a/Fregat. Performances of REGULUS propulsion system are evaluated after the initial commissioning of UNISAT-7. This key IOD mission paves the way to next UNISAT programs, where GAUSS microsatellites will be able to execute orbital maneuvers before any single CubeSat deployment, in order to efficiently shape customized constellations by using UNISATs as autonomous vehicles for in-orbit-deployment. Provide an informative abstract of no more than 500 words. The abstract should stand alone as a summary of the paper, not as an introduction (i.e., no numerical references). Type the abstract across both columns and fully justified

REGULUS CubeSat Propulsion System: In-Orbit Operations

A robust, versatile, and cost-effective propulsion system to provide wide mobility to small satellite platforms and nanosatellite deployers. A Plug&Play propulsion system designed to be easily integrated into different satellite platforms and to match customer\u27s requirements, with minimal customization efforts and costs

REGULUS Iodine Electric Propulsion System Integration in CubeSats’ Platforms and Testing

REGULUS is an electric propulsion (EP) system for CubeSats at TRL8 and now waiting for the IoD flight in late 2020. REGULUS system is provided for integration with all electronics, fluidic line, iodine tank and structures for total mass below 3 kg. Thanks in particular to the Magnetically Enhanced RF Plasma Thruster (MEPT) technology and the use of iodine propellant, the system can provide 3000Ns of total impulse in a 93.8 x 95.0 x 150.0 mm volume performance, fitting in a 1.5U Cubesat. REGULUS includes the whole propulsion package for integration in CubeSats and MicroSats as well as small CubeSat carriers. The system is composed by the thruster, the electronics (PPUs and PCU) the fluidic line and the tank. The main features of REGULUS are the presence of a simple architecture, a thruster with no neutralizer and grids, no high DC-voltage PPU and the use of solid iodine as propellant, that can be substituted with Xenon fluidic line and tank when required. Its first mission will be onboard of Unisat-7 by GAUSS. The flight will take place in late 2020 in a Soyuz flight. During the mission, REGULUS will allow Unisat-7 to perform an orbit descending maneuver, drag compensation in VLEO and decommissioning

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio