Dans les analyses de sûreté du futur réacteur à fusion ITER, on anticipe un accident de perte de vide susceptible de mettre en suspension des particules produites et déposées sur les parois du tore. L’objectif de cette thèse est de fournir des données expérimentales fiables afin de développer et valider un modèle de mise en suspension (MES), prenant en compte la basse pression et prévoyant les fractions de particules mobilisées lors d’un tel évènement. Pour ce faire, des expériences ont été effectuées en fonction des paramètres clés — diamètre des particules, vitesse de frottement et masse volumique — entrant dans le mécanisme de MES. L’analyse de la granulométrie des particules de tungstène produites en tokamak met en évidence des diamètres allant de 0,1 à 10 µm. Les résultats expérimentaux de MES de dépôts monocouche sont en bon accord avec le model Rock’nRoll lorsque les particules sont uniquement mobilisée par le fluide. Cependant, une mobilisation des particules fines par agglomération, non prise en compte dans les modèles de MES, a été mise en évidence. Mes expériences ont aussi révélé l’importance de la structure (porosité et épaisseur) des dépôts multicouches dans le mécanisme de MES avec, là encore, une mobilisation par agglomération de particules. L’effet de la basse pression dans la mise en suspension a été étudié entre 10 et 1 000 mbar et doit se poursuivre à plus basse pression. Mes résultats de MES montrent une réduction du frottement dans les forces aérauliques à basse pression. Enfin, les mesures de la cinétique du phénomène de MES ont mis en évidence trois zones distincts avec un effet à court terme, un effet à long terme et une zone de transition qui devront être pris en compte dans un calcul de MES. / In ITER, a loss of vacuum accident is likely to re-suspended particles produced and deposited on the torus walls. The thesis purpose is to provide reliable experimental data to develop and validate a re-suspension model, taking into account the low pressure and predicting the amount of particles mobilized during such event. Experiences were carried out as a function of key parameters — particle diameter, friction velocity and density of the atmosphere — entering in the re-suspension mechanism. The size distribution of tungsten particles specific to fusion reactors was obtained from a collection in the AUG tokamak: modes at 0,8 µm and at 1,6 µm. The adhesion forces, adjustment parameters of most re-suspension models, were measured by Atomic Forces Microscopy (AFM). Experimental data of re-suspension of monolayer and multilayers deposits were acquired in two wind-tunnels: BISE-II (Saclay) and AWTS-II (Aarhus). For the monolayer deposits, the re-suspended particle fractions were measured by size bins, for friction velocities of 1.0 and 1.5 m.s-1 at 1,000 mbar, and of 1.0 m.s-1 at 300 mbar. Regarding the multilayers deposits, the re-suspension was measured for five surrounding pressures (25, 60, 10, 300 and 1,000 mbar), constituting a valuable data base for the development of a re-suspension model taking into account the mobilisation by particle clustering and the effect of a low pressure. Finally, measurements of the MES phenomenon kinetic highlighted three distinct regions with a short-term effect, long-term effect and a transition region which must be taken into account in a MES calculation.

Financial support is one of the main ways in which the Swedish government can encourage restoration and construction of wetlands. Despite having the tool of financial support for constructing wetlands in place, there is little information on how the support systems are structured and how they compare to each other. Another knowledge gap is the regional variation in wetland construction among counties and how this differs between them.  The purpose of this study is therefore two-part. Firstly, to map and compare the three main financial systems for constructing wetlands in Sweden, namely LOVA (the Local Water Preservation Grant), LONA (the Local Initiative for Nature Conservation) and the RDP (the Rural Development Programme). Results from the national comparison among financial systems shows that the RDP is the significantly most influential grant in wetland construction, whereas LOVA make up 9% and LONA 1% of the sum of hectares of constructed wetlands. These findings are the reason why this study only uses the RDP as a basis for the second purpose of this study, which is to investigate the regional variation in wetland construction. These results reveal two main findings, firstly that Skåne is the county with the most constructed wetlands, both in terms of hectares and number of wetlands. Finally, the purposes of the constructed wetlands which are financed by the RDP, are reviewed in this study. The purposes differ greatly between counties and do not necessarily align with the targets set in the Regional Action Plans.  The reasons for the large variations between counties, the low numbers of constructed wetlands within LONA and the administrative process of the RDP are topics which are recommended to research further.

<p dir="ltr">Additive manufacturing (AM) of gun propellants is an emerging and promising field which addresses the limitations of conventional manufacturing techniques. Overall, this thesis is a body of work which serves to bridge the gap between fundamental research and application of additively manufactured gun propellants.</p>