Le contexte industriel de cette étude est la modification de surface de l’alliage 690(60%Ni, 30%Cr, 10%Fe) utilisé dans la fabrication de tubes de générateurs de vapeur.L’objectif de ce travail de thèse est donc de former, par traitement de fusion par laser nanopulsé, une couche de Cr2O3 étanche au relâchement du nickel. Pour maîtriser la formation decette couche, il est primordial de déterminer les paramètres opératoires influant sur lespropriétés de cette couche. L’objectif scientifique est alors d’expliquer les phénomènesintervenant pendant et après l’impulsion laser au niveau de l’extrême surface.Suite à une étude paramétrique détaillée, un traitement de fusion superficielle par laser nanopulsé a permis d’obtenir un fort rapport Cr/Ni en surface et une couche d’oxyde dense etcontinue. Afin de vérifier l’efficacité du traitement, des coupons traités ont été introduits dansune boucle simulant le milieu primaire.Des expériences et des calculs ont été mis en oeuvre pour tenter d’expliquer l’enrichissementen chrome de la surface à l’aide de ce procédé. Les résultats expliquent l’enrichissement enchrome jusqu’à la solidification du bain liquide en surface qui précède la formation du Cr2O3favorisée par la forte affinité du chrome avec l’oxygène et la grande stabilité de l’oxyde Cr2O3. / Alloy 690 (60%Ni, 30%Cr, 10%Fe) is mainly used in primary circuit pipes fornuclear power plants.The aim of this thesis is to form a Cr2O3 layer, using laser surface melting, with the objective ofcreating a chromium-rich oxide layer. In order to optimize the treatment, it was first important todetermine parameters influence on the layer oxide properties then, with the objective of adeeper understanding of mechanisms involved, to address thermo-physical phenomenaoccurring during and after the laser pulse striking the upper surface.A deep parametric study first enabled to find an optimized laser surface treatment whichproduces chromium enrichment of the upper surface and a dense and continuous oxide layer.This treatment has been applied on samples, set in a primary medium simulation loop.Experiments and calculations were carried out to provide understanding of surface chromiumenrichment by laser process. The results were shown to explain chromium enrichment until meltpool solidification occurred on the upper surface, assumingly just before chromium oxideformation. This was also promoted by a high affinity with oxygen and a higher stability of Cr2O3oxide compared with other potential oxide formation.

Magnesiumwerkstoffe sind aufgrund ihrer geringen Dichte und hohen spezifischen Festigkeit für den Leichtbau prädestiniert. Ziel der vorgelegten Arbeit ist es, durch die gleichzeitige Verbesserung des Korrosions- und Verschleißverhaltens neue Anwendungsfelder für Magnesiumlegierungen zu erschließen. Anhand der Magnesiumlegierung AZ91D wurden die Möglichkeiten einer lokalen beanspruchungsgerechten Modifikation von Struktur und Gefüge im oberflächennahen Bereich durch eine Elektronenstrahl(EB)-Flüssigphasen-Randschichtbehandlung ohne Zusatzstoff (EB-Umschmelzen) und unter Verwendung von Al-Si-Zusatzstoffen (EB-Umschmelzlegieren) aufgezeigt. Die mittels verschiedener hochfrequenter Strahlablenktechniken erzeugten Schichten weisen eine deutliche Gefügefeinung, neue Gefügemorphologien sowie eine veränderte Phasenverteilung und/oder -neubildung auf, sind riss- und porenfrei und haben eine ausgezeichnete schmelzmetallurgische Anbindung an den Grundwerkstoff. Anhand von Tauchversuchen und potentiodynamischen Polarisationsmessungen in verschieden konzentrierten NaCl-Lösungen konnte eine signifikante Verbesserung des Korrosionsverhaltens der generierten Schichten im Vergleich zum Ausgangszustand nachgewiesen werden. EB-umschmelzlegierte Schichten weisen im Ergebnis von Trockenverschleißtests (Stift-Scheibe) eine deutliche Reduzierung des spezifischen Verschleißkoeffizienten auf.

This thesis aims to investigate the use of additive manufacturing (AM) as a novel manufacturing process for the production of milli-scale chemical reaction systems. Five well developed additive manufacturing techniques; stereolithography (SL), selective laser melting (SLM), fused deposition modelling (FDM), ultrasonic additive manufacture (UAM) and selective laser sintering (SLS) were used to manufacture a number of miniaturised flow devices which were tested using a range of organic and inorganic reactions. SL was used to manufacture a range of functioning milli-scale flow devices from Accura 60 photoresin, with both simple and complex internal channel networks. These devices were used to perform a range of organic and inorganic reactions, including aldehyde and ketone functional group interconversions. Conversion of products within these reactors, were shown to be comparable to commercially available milli-scale coil reactors. More complex designs, which allowed SL parts to be integrated to existing flow and analytical instrumentation, allowed us to develop an automated reaction analysis and optimisation platform. This platform allowed precise control over the reaction conditions, including flow rate, temperature and reagent composition. We also designed a simplex type reaction optimisation software package that could input data in the form of reaction conversions, peak intensities, and thermocouple data, and generate a new set of optimal reaction conditions. SL parts which incorporated embedded analytical components were also manufactured, which allowed us to perform inline reaction analysis as a feedback method for input into the optimisation platform. Stereolithography was shown to be a highly versatile manufacturing method for designing and producing these flow devices, however the process was shown to be still limited by the range of processable materials currently commercially available. SLM was also used to manufacture a number of functioning milli-scale flow devices from stainless steel and titanium, which had simplistic internal channel designs of diameters ranging from 1 to 3 mm. Again, SLM parts were manufactured which incorporated embedded analytical components, which could be integrated into an automated reaction platform. These devices, unlike parts produced via SL, could be attached to heating platforms to allow us to perform high temperature reactions. This control over the reaction temperature formed an essential part of the reaction optimisation platform. These parts were again used to perform a ketone functional group interconversion. Internal structures of these SLM parts were also visualised via micro computed tomography (μCT or microCT) scanning as well as optical microscopy. FDM was used throughout the project as an inexpensive method of prototyping parts which were to be manufactured via more expensive manufacturing processes. This prototyping allowed the optimisation of intricate design features, such as the manufacture of an inline spectroscopic flow cell for integration with a commercially available LC system. FDM was also proposed as a customisable approach to designing and manufacturing flow devices with embedded components, however the current limitations in build resolution and materials choices severely limited the use of FDM for this application. UAM was also proposed as a novel manufacturing process whereby the build process would allow discrete components to be embedded directly into a flow channel. This was demonstrated by embedding a type-k thermocouple across a 2 mm channel. The data from this thermocouple was monitored during a heated reaction, and used as a method of determining the exact reaction conditions the reaction medium was being exposed to. SLS was also proposed as a possible manufacturing method for milli-scale flow devices, however it proved difficult to remove un-sintered powder from parts with internal channel diameters as high as 5 mm. It was shown that this powder was forming a dense semi solid, due to the large degree of shrinkage upon cooling of the SLS parts, which was compressing the powder. More research into optimum processing conditions is required before SLS could be used for the production of intricate channel networks.

Das selektive Laserschmelzen (SLM) erlaubt komplexe Geometrien zu fertigen, die, z. B. in Form von integrierten Kühlkanälen, bei Werkzeugen von großer Bedeutung sind. Aktuell werden in der Industrie hauptsächlich Aluminium-, Stahl-, Titan-, Nickel- und Kobaltchromlegierungen mit SLM verarbeitet. Für die additive Fertigung sind Stähle interessant, die besondere Eigenschaften aufweisen. So wird für Konstruktionsbauteile größtenteils korrosionsbeständiger Stahl verwendet. Ein weiteres Anwendungsfeld ist die Herstellung von Werkzeugen. Die besonderen Ansprüche an die mechanischen Eigenschaften, die für Werkzeuge benötigt werden, erfüllen die Werkzeugstähle. Durch die Neigung zu Rissbildung und Verzug resultiert eine herausfordernde Verarbeitbarkeit im SLM-Prozess. Werkzeugstähle wurden bisher auf Grund dieser Herausforderungen selten mit SLM prozessiert. Es besteht daher ein großer Bedarf die Zusammenhänge zwischen dem Prozess, der Verarbeitbarkeit, dem entstehenden Gefüge und den resultierenden Eigenschaften aufzuklären. In dieser Arbeit werden die Mikrostruktur und die mechanischen Eigenschaften dreier hochfester Stahllegierungen, verarbeitet im SLM-Prozess, untersucht. Eine Legierungsentwicklung, speziell auf die Anforderungen des SLM-Prozesses zugeschnitten, ermöglicht, das volle Potenzial des SLM-Prozesses auszuschöpfen. Die Verarbeitbarkeit der neu entwickelten Legierung im SLM-Prozess konnte erfolgreich gegenüber den Ausgangslegierungen verbessert werden.

In this thesis we mainly focus on the study of the turbulent transport of impurity particles in the plasma due to the electrostatic drift wave microinstabilities. In a fusion reactor, the helium produced as a result of the fusion process is an internal source of impurity. Moreover, impurities are released from the material surfaces surrounding the plasma by a variety of processes: by radiation from plasma, or as a result of sputtering, arcing and evaporation. Impurities in tokamak plasmas introduce a variety of problems. The most immediate effect is the radiated power loss (radiative cooling). Another effect is that the impurity ions produce many electrons and in view of the operating limits on density and pressure, this has the effect of replacing fuel ions. For example, at a given electron density, $n_{e}$, each fully ionized carbon ion (used in the wall materials in the form of graphite) replaces six fuel ions, so that a 7\\% concentration of fully ionized carbon in the plasma core, would reduce the fusion power to one half of the value in a pure plasma. Therefore, for all tokamaks it become an immediate and continuing task to reduce impurities to acceptably low concentrations. However, the presence of impurities, with control, can be beneficial for the plasma performance and reduction of strong plasma heat loads on the plasma facing walls. The radiative cooling effect which was mentioned above can be used at the edge of the plasma in order to distribute the plasma heat more evenly on the whole surface of the vessel walls and therefore, reduce significantly plasma heat bursts on the small regions on the divertor or limiter tiles. The experiments at TEXTOR show that the presence of the impurities at the plasma edge can also improve the performance and reduce the turbulent transport across the magnetic field lines. The observed behavior was explained trough the proposed mechanism of suppression of the most important plasma drift wave microinstability in this region, namely, the Ion Temperature Gradient mode (ITG mode) by the impurities. The impurity's positive impact on the plasma performance offered a possibility to better harness the fusion power, however, it is vital for a fusion reactor to have feedback controls in order to keep impurities at the plasma edge and limit their accumulation in the plasma core where the fusion reactions are happening. In order to have control over the impurity transport we first need to understand different mechanisms responsible for its transport. <p><p>One of the least understood areas of the impurity transport and indeed any plasma particle or heat transport in general, is the turbulent transport. Extensive efforts of the fusion plasma community are focused on the subject of turbulent transport. Motivated by the fact that impurity transport is an important issue for the whole community and it is an area which needs fundamental research, we focused our attention on the development of turbulent transport models for impurities and their examination against experiments. In a collaboration effort together with colleagues (theoreticians as well as experimentalist) from different research institutes, we tried to find, through our models, physical mechanisms responsible for experimental observations. Although our main focus in this thesis has been on the impurity transport, we also tried a fresh challenge, and started looking at the problem of drift wave turbulent transport in a different framework all together. Experimental observation of the edge turbulence in the fusion devices show that in the Scrape of Layer (SOL: the layer between last closed magnetic surface and machine walls) plasma is characterized with non-Gaussian statistics and non-Maxwellian Probability Distribution Function (PDF). It has been recognized that the nature of cross-field transport trough the SOL is dominated by turbulence with a significant ballistic or non-local component and it is not simply a diffusive process. There are studies of the SOL turbulent transport using the 2-D fluid descriptions or based on probabilistic models using the Levy statistics (fractional derivatives in space). However, these models are base on the fluid assumptions which is in contradiction with the non-Maxwellian plasmas observed. Therefore, we tried to make a more fundamental study by looking at the effect of the non-Maxwellian plasma on the turbulent transport using a gyro-kinetic formalism. We considered the application of fractional kinetics to plasma physics. This approach, classical indeed, is new in its application. Our aim was to study the effects of a non-Gaussian statistics on the characteristic of the drift waves in fusion plasmas.<p><p>Ce travail de thèse porte sur le transport turbulent d'impuretés dans les plasmas de fusion<p>par confinement magnétique. C'est une question de la plus haute importance pour le développement<p>de la fusion comme source d'énergie. En effet, une accumulation d'impuretés au coeur<p>du plasma impliquerait des pertes d'énergie par radiation, conduisant par refroidissement à<p>l'extinction des réactions de fusion. Il est par contre prévu d'injecter des impuretés dans le<p>bord du plasma, afin d'extraire la chaleur par rayonnement sans endommager les éléments de<p>la première paroi. Ces contraintes contradictoires nécessitent un contrôle précis du transport<p>d'impuretés, afin de minimiser la concentration d'impuretés au coeur du plasma tout en la<p>maximisant au bord. Une très bonne connaissance de la physique sous-jacente au transport<p>est donc indispensable. L'effet de la turbulence, principal mécanisme de transport, sur les impuretés<p>est alors une question centrale. Dans cette thèse, un code numérique, AFC-FL, a été développé sur la base d'une approche ``fluide' linéaire pour la turbulence d'ondes de dérive. Il calcule les taux de croissance qui caractérisent la rapidité de l'amorçage des instabilités. L'analyse de stabilité est complétée par l'évaluation des taux de croissance en présence d'un gradient de densité, un cisaillement magnétique ou un nombre arbitraire de différentes espèces d'impureté. Les formules complètes du flux turbulent d'impuretés pour ces taux de croissance calculés des instabilités des ondes de dérive ont été dérivées. Un modèle de transport anormal qui nous permet d'étudier la dépendence du transport en fonction de la charge d'impureté a été développé. Ce modèle prend en compte les effets collisionnels entre les ions, l'impureté et les particules principales de plasma. Une telle dépendence du transport anormal en fonction de la charge de l'impureté est observée dans les expériences et il a été montré que les résultats obtenus sont en bon accord avec les observations expérimentales. Nous avons également étudié l'effet des impuretés sur le confinement de l'énergie dans les plasmas du tokamak JET. La modélisation de transport a été exécutée pour des plasmas avec injection de néon dans la périphérie du tokamak. Cette technique est utilisée afin d'extraire la chaleur par rayonnement sans endommager la paroi et pour réduire certaines instabilités (ELM). Des simulations du code RITM ont été comparées à des mesures effectuées lors d'expériences au JET. Il a été montré que l'injection de néon mène toujours à une dégradation du confinement par rapport aux décharges sans néon. Cependant, l'augmentation de la charge effective, en raison du presence du néon peut diminuer le taux de croissance d'autres instabilité (ITG) et amèliorer le confinement du coeur du plasma. Ce confinement amélioré du coeur peut alors compenser la dégradation au bord et le confinement global du plasma peut s'améliorer. <p> / Doctorat en sciences, Spécialisation physique / info:eu-repo/semantics/nonPublished

Several malignant diseases, such as colorectal, pancreatic, breast or ovarial cancers, are primarily treated with cytostatics 5-fluorouracil (5-FU). 5-FU undergoes biotransformation in human body and arising metabolites induce the damage and subsequent apoptosis in the target cells. The main aim of this diploma Thesis was the determination of methylation in promoter regions of 14 candidate genes participating on 5-FU biotransformation: TK1, PPAT, RRM1, RRM2, UCK2, UCK1, UMPS, TYMP, UPP1, UPP 2 SLC29A1, UPB1, DPYS and DPYD. We hypothesize that the methylation in promoter regions regulates mRNA transcription of the above candidate genes. We have conducted appropriate analyses in 128 colorectal cancer patients, for whom both tumor and nonmalignant adjacent tissues were available. Sample processing and analysis involved DNA isolation, bisulfite conversion of unmethylated cytosines to corresponding uracils, methylation-specific analysis of melting curves with high resolution for theproper methylation analysis and gel electrophoresis to separate PCR products. For the majority of the studied genes (TK1, PPAT, RRM1, RRM2, UCK2, UCK1, UMPS, TYMP, UPP1, SLC29A1 and DPYD) we did not detect any aberrant methylation in promoter regions. In genes DPYS, UPB1 and UPP2 we recorded various degree of promoter...

Abstract A blast furnace is the dominant process for making iron in the world. Iron ore pellets are commonly used as iron burden materials in a blast furnace, in which iron oxides are reduced to metallic molten iron. While descending, the charge faces various stresses, which affect the gas flows in the shaft and the energy efficiency of the process. Charge material testing on a laboratory scale is of crucial importance in regard to the development of material quality. This doctoral thesis presents a couple of advanced novel experimental methods: a novel camera imaging method to determine the amount of swelling during reduction; a novel reducibility test to determine the reducibility in a solid state under simulated blast furnace conditions; and a novel experimental program for the ARUL reduction-softening test to more accurately simulate blast furnace conditions. Swelling tests under conditions of fixed temperature and gas composition showed that isothermal tests do not give a realistic insight into the material behaviour in a blast furnace. As a result, it is suggested that dynamic gas composition – temperature programmes simulating actual process conditions should be used. Additionally, the test results showed that circulating elements (sulphur and potassium) also affect the pellet volume change during reduction, however no abnormal swelling was observed in any of the swelling experiments. The factors affecting the high-temperature properties of iron burden materials for blast furnace use were evaluated by both the experimental methods and computational thermodynamics. It was shown that none of the studied pellet grades has as good reduction-softening properties as the fluxed sinter because of the differences in the chemistry and macro-porosity. FeO-SiO2-CaO-MgO-Al2O3 system examinations with FactSage was found to be a useful tool for predicting the softening of an iron burden material using the original chemical composition. FactSage computations suggest that the softening properties of an iron burden material can be improved either by decreasing the proportion of SiO2, increasing the proportion of MgO or introducing an appropriate amount of CaO in relation to the proportion of SiO2. / Tiivistelmä Masuuni on merkittävin raakaraudan valmistusprosessi maailmassa. Masuunissa käytetään yleisesti rautamalmipellettejä rautapanosmateriaalina. Masuunissa raudanoksidit pelkistetään metalliseksi rautasulaksi. Vajotessaan panos kohtaa monenlaisia rasitteita, joilla on vaikutusta kuilun kaasuvirtauksiin ja masuuniprosessin energiatehokkuuteen. Panosmateriaalien testaus laboratoriomittakaavassa on merkittävässä roolissa, kun niiden laatua kehitetään. Väitöskirjassa esitetään useita kehittyneitä koemenetelmiä: uusi kamerakuvausmenetelmä, jolla voidaan määrittää turpoaminen pelkistyksen edetessä; uusi pelkistyvyystesti, jolla voidaan määrittää rautapanosmateriaalin pelkistyminen kiinteässä tilassa masuunia jäljittelevissä olosuhteissa; ja uusi koeohjelma, jolla voidaan jäljitellä aiempaa tarkemmin masuuniolosuhteita sulamis-pehmenemiskokeessa. Turpoamistestit vakioiduissa olosuhteissa osoittivat, että isotermiset testit eivät anna realistista kuvaa materiaalin käyttäytymisestä masuunissa. Tämän vuoksi dynaamisia kaasukoostumus–lämpötila-ohjelmia tulisi suosia. Lisäksi tutkimustulokset osoittavat, että myös masuunissa kiertävillä komponenteilla (rikillä ja kaliumilla) on vaikutusta pelletin tilavuuden muutokseen pelkistyksessä. Yhdessäkään turpoamiskokeessa ei kuitenkaan havaittu katastrofaalista turpoamista. Masuunin rautapanosmateriaalien korkealämpötilaominaisuuksiin vaikuttavia tekijöitä arvioitiin sekä kokeellisin menetelmin että termodynaamisin laskelmin. Yhdelläkään tutkitulla pellettilaadulla ei havaittu sintterin veroisia korkealämpötilaominaisuuksia, mikä johtuu eroista kemiallisessa koostumuksessa ja makrohuokoisuudessa. FeO-SiO2-CaO-MgO-Al2O3 systeemitarkastelut rautapanosmateriaalin lähtökoostumuksella todettiin toimivaksi menetelmäksi arvioida panosmateriaalin pehmenemiskäyttäytymistä. FactSage-laskennat antavat ymmärtää, että rautapanosmateriaalin pehmenemisominaisuuksia voidaan parantaa joko vähentämällä SiO2:n osuutta, lisäämällä MgO:n osuutta tai lisäämällä CaO:ta sopiva määrä SiO2:n osuuteen nähden.

L'objectif de cette thèse est d'étudier les transformations physico-chimiques lors de l'élaboration d'un verre à partir d'un mélange granulaire. Les mélanges vitrifiables industriel formant des verres de vitrage ou de conditionnement sont approchés par le système à trois oxydes SiO2-CaO-Na2O, apportés sous forme de sable, de calcaire et de carbonate de sodium. Cette simplification permet d'étudier le lien entre microstructrure de l'empilement granulaire et transformations pendant le chauffage. La variété des chemins réactionnels entre les grains de matières premières transmet en effet l'hétérogénéité du mélange au verre. Le système ternaire est décomposé en deux sous-systèmes. D'une part, les réactions entre le disilicate de sodium et 4 porteurs de calcium (CaCO3, CaO, CaSiO3, Ca2SiO4) révèlent la formation de couches d'espèces cristallines entre le grain calcique en cours de dissolution et le silicate fondu. D'autre part, la synthèse ex situ de carbonate mixte de calcium et de sodium est réalisée. Ce produit est analysé et caractérisé ; son apparition in situ dans un mélange ternaire est observée, et sa réaction avec la silice est étudiée. Dans un mélange vitrifiable silico-sodocalcique, la tomographie X in situ et post mortem montre l'importance de phénomènes transitoires de mouillage et de dégagement gazeux qui orientent les réactions chimiques. En particulier, un mécanisme local et de courte durée convertit une profondeur limitée des grains de calcaire en carbonate mixte. Enfin, l'homogénéité du verre obtenu à 1300°C est étudiée à l'aide d'une méthode de déconvolution de spectres Raman innovante, pour plusieurs granulométries et espèces porteuses de calcium. / This thesis focuses on the physical and chemical transformations undergone by a granula glass batch during the glass making process. Industrial window or container glass batches are complex mixtures, that we approached by the ternary oxide system SiO2-CaO-Na2O. Industrial raw materials, namely silica sand, limestone and sodium carbonate, are used. This simplification makes it possible to study the coupling between the granular microstructure and the physical and chemical transformations during the heating. Indeed, the multiple possible reaction paths propagate the heterogeneity of the granular batch to the glass. To support our study of the ternary system, two sub-system are investigated. On one hand, reactions between sodium disilicate and 4 calcium-bearing species (CaCO3, CaO, CaSiO3, Ca2SiO4) show the formation of successive layers of crystalline intermediate species between the dissolving grains and the molten silicate. On the other hand, sodium calcium mixed carbonate is synthesized ex situ and characterized. Its formation in a ternary glass batch is observed in situ, and its reactivity with silica is studied. In a ternary soda-lime glass batch, X-ray in situ and ex situ microtomography reveals the significance of wetting and degassing phenomena in orienting the grains towards a reaction path. Conversion of a limited depth of limestone grains into mixed carbonate for a short time is notably witnessed. This mechanism is strongly dependent on the grains surrounding limestone particles. Finally, we use an innovative deconvolution procedure to measure the impact of granulometry and the nature of calcium-bearing raw materials on the final glass homogeneity.

No description available.

The accretionary Mesoproterozoic Grenville Orogeny (ca. 1300 – 980 Ma) involving the Central Metasedimentary Belt is a key building block of the eastern Laurentian margin. A petrographic, mineralogical, geochemical and geochronological study of the migmatite complex in Otter Lake (QC) within the Marble Domain is used to resolve regional metamorphic and magmatic events primarily recorded in the leucosome accessory minerals (i.e. monazite). The relationship between the different stages of monazite and garnet growth and dissolution during the tectonic evolution of the orogenic history for the interpreted metasomatic (injected) and anatectic (in situ) monazite-bearing neosomes from this study supports published thermochronological work in the area and challenges the claim that the Central Metasedimentary Belt was not heated above 500 °C during the Ottawan phase. Instead, the region shows Grenville magmatic and anatectic events were overprinted by high-temperature, fluid-rich Ottawan-phase metamorphism recorded within both injected (monazite-bearing) and in situ (monazite- and garnet-bearing) neosomes.