The properties of transition metal clusters differ from those of both atomic and bulk size regimes. Such clusters are incompletely understood and potentially useful, making them attractive targets for further study. The very smallest clusters studied in this thesis (CuO, Cu₂ and Cu₃) have been investigated with velocity map imaging. 1+1' photodissociation of CuO X ²Π_3/2 was observed, via the C, D, E, F and H states of CuO. CuO* was photodissociated to form Cu(²D_3/2) + O(¹D₂). D₀(CuO) was determined to be 3.041±0.030 cm^-1. Non-resonant three-photon Cu₂ photodissociation occurred throughout the energy range studied to produce one ground-state and one highly-excited copper atom,Cu*. Cu* was ionised by a single additional visible photon. Nearly all Cu* atoms with internal energies between 41000 and 53000 cm^-1 were observed. D₀(Cu₂) has been calculated to be 1.992±0.037 eV. Features arising from photodissociation of Cu₃ were observed in the Cu^+ and Cu₂^+ ion yield spectra and images. Their structure was ill-resolved due to uncertainties in the internal energy of both parent Cu₃ and product Cu₂. These features correspond to single-photon dissociation of Cu₃ to produce metastable D-states of the copper atom and vibrationally excited Cu₂. One series of features implies a previously-unobserved state of either Cu₂ or Cu₃. Rh_nN₂O^+ and Rh_nON₂O^+ (n=5, 6) were collisionally activated in collision-induced dissociation (CID) experiments with Ar and ¹³CO. These experiments were carried out in a Fourier Transform Ion Cyclotron Resonance(FT-ICR)spectrometer. Argon collisions induced both N₂O desorption and N₂O reduction. The branching ratios observed reproduced those seen in prior IR-MPD experiments. ¹³CO was observed to chemisorb to the cluster upon collision, activating not only N₂O desorption and reduction but also CO oxidation. Formation of CO2 was noted to be particularly rapid on the n=5 cluster compared to the n=6 cluster. Reactions of Rh_nN₂O^+ (n=4-6) clusters were also activated by black body radiation. This technique is known as BIRD - black-body induced infrared radiative dissociation. These studies revealed that the N₂O desorption barrier exceeds the N₂O reduction barrier on all clusters studied, but that the entropic favourability of desorption increases its rate relative to reduction with increasing cluster internal energy. The BIRD rate was much reduced upon cooling the ICR cell to 100 K. A further test of the BIRD mechanism increased the number of N₂O ligands and hence the absorption rate. An approximately linear increase in the dissociation rate of Rh_n(N₂O)_m^+ was observed with index m. Deviations from linearity were caused by variations in the N₂O desorption rate. In the case of Rh₅(N₂O)_m^+, desorption rates corresponded closely to N₂O binding energies calculated by density functional theory. The system was modelled using a master equation approach.

In Sweden, utilisation of incinerator residues outside disposal areas is restricted by environmental concerns, as such residues commonly contain greater amounts of potentially toxic trace elements than the natural materials they replace. On the other hand, utilisation can also provide environmental benefits by decreasing the need for landfill and reducing raw material extraction. This thesis provides increased knowledge and proposes better approaches for environmental assessment of incinerator residue utilisation, particularly bottom ash from municipal solid waste incineration (MSWI).A life cycle assessment (LCA) based approach was outlined for environmental assessment of incinerator residue utilisation, in which leaching of trace elements as well as other emissions to air and water and the use of resources were regarded as constituting the potential environmental impact from the system studied. Case studies were performed for i) road construction with or without MSWI bottom ash, ii) three management scenarios for MSWI bottom ash and iii) three management scenarios for wood ash. Different types of potential environmental impact predominated in the activities of the system and the scenarios differed in use of resources and energy. Utilising MSWI bottom ash in road construction and recycling of wood ash on forest land saved more natural resources and energy than when these materials were managed according to the other scenarios investigated, including dumping in landfill. There is a potential for trace element leaching regardless of how the ash is managed.Trace element leaching, particularly of copper (Cu), was identified as being relatively important for environmental assessment of MSWI bottom ash utilisation. CuO is suggested as the most important type of Cu-containing mineral in weathered MSWI bottom ash, whereas in the leachate Cu is mainly present in complexes with dissolved organic matter (DOM). The hydrophilic components of the DOM were more important for Cu binding than previously understood. Differences were also observed between MSWI bottom ash DOM and the natural DOM for which the geochemical speciation models SHM and NICA-Donnan are calibrated. Revised parameter values for speciation modelling are therefore suggested. Additions of salt or natural DOM in the influent did not change the leachate concentration of Cu. Thus, although Cl and natural DOM might be present in the influent in the field due to road salting or infiltration of soil water, this is of minor importance for the potential environmental impact from MSWI bottom ash.This thesis allows estimates of long-term leaching and toxicity to be improved and demonstrates the need for broadening the system boundaries in order to highlight the trade-offs between different types of impact. For decisions on whether incinerator residues should be utilised or landfilled, the use of a life cycle perspective in combination with more detailed assessments is recommended. / QC 20100914

La modélisation des efforts de coupe en usinage est nécessaire pour prédire certaines caractéristiques de la pièce usinée comme sa géométrie, son état de surface ou encore l'intégrité de la matière en sub-surface.Les nombreux modèles d'efforts de coupe déjà développés sont souvent appliqués dans le cas d'opérations d'usinage simples, ce qui limite leur diffusion vers le milieu industriel, alors qu'il existe un réel besoin de modélisation d'opérations d'usinage complexes et variées, et prenant en compte d'éventuels changements métallurgiques au niveau du matériau usiné.L'objectif de ces travaux est de proposer un modèle d'efforts de coupe appliqué à toute opération de tournage d'une part et considérant certaines propriétés mécaniques du matériau usiné d'autre part.Concernant l'aspect multi-opérations, un modèle géométrique utilisant des transformations homogènes a été développé et permet de décrire à la fois la trajectoire et la géométrie de l'outil. Les effets de paramètres originaux, tels que le diamètre de la pièce, l'angle de direction d'arête et le rayon de bec, sont étudiés, notamment à l'aide de nouvelles configurations de coupe élémentaires. La prise en compte de ces paramètres dans les relations de coupe locales permet finalement d'améliorer la simulation des efforts de coupe lors d'un contournage.L'approche utilisée pour l'aspect multi-matériaux consiste à modifier progressivement le matériau usiné. Ainsi, le matériau initial, le cuivre pur, a été étudié dans différents états métallurgiques, obtenus par des traitements thermo-mécaniques. En particulier, le procédé d'extrusion coudée à aires égales (ECAE) a été utilisé afin d'écrouir le matériau dans la masse. Ainsi, trois matériaux aux caractéristiques mécaniques différentes mais conservant plusieurs caractéristiques communes (thermiques notamment) ont pu être comparés en termes d'efforts de coupe. Les coefficients des relations de coupe sont finalement mis en regard des propriétés mécaniques obtenues par des essais de traction et de compression à grande vitesse. / The cutting forces have to be known as accurately as possible in order to predict the characteristics of the workpiece as the geometry, the roughness or the material integrity.Numerous models have been yet developed; however, the majority cannot be used for the various industrial cutting operations and remain confined for a single machined material.The objective of this study is to develop a cutting forces model applied to any turning operation and taking into account some mechanical characteristics of the machined material.First, a geometrical model based on homogeneous transformations is presented. Then, the effects of some parameters, like the workpiece diameter, the cutting edge angle and the nose radius, are studied by using new cutting configurations, in order to improve the cutting laws.The multi-material aspect is approached by modifying the metallurgical state with thermo-mechanical treatments, especially by using the equal channel angular extrusion process in order to harden the material in the mass. Finally, the coefficients of the local cutting relations are compared to mechanical characteristics obtained from tensile and high compression tests.

A key challenge facing the nuclear fusion community is how to design a reactor that will operate in environmental conditions not easily reproducible in the laboratory for materials testing. Finite element analysis (FEA), commonly used to predict components’ performance, typically uses idealised geometries. An emerging technique shown to have improved accuracy is image based finite element modelling (IBFEM). This involves converting a three dimensional image (such as from X ray tomography) into an FEA mesh. A main advantage of IBFEM is that models include micro structural and non idealised manufacturing features. The aim of this work was to investigate the thermal performance of a CFC Cu divertor monoblock, a carbon fibre composite (CFC) tile joined through its centre to a CuCrZr pipe with a Cu interlayer. As a plasma facing component located where thermal flux in the reactor is at its highest, one of its primary functions is to extract heat by active cooling. Therefore, characterisation of its thermal performance is vital. Investigation of the thermal performance of CFC Cu joining methods by laser flash analysis and X ray tomography showed a strong correlation between micro structures at the material interface and a reduction in thermal conductivity. Therefore, this problem leant itself well to be investigated further by IBFEM. However, because these high resolution models require such large numbers of elements, commercial FEA software could not be used. This served as motivation to develop parallel software capable of performing the necessary transient thermal simulations. The resultant code was shown to scale well with increasing problem sizes and a simulation with 137 million elements was successfully completed using 4096 cores. In comparison with a low resolution IBFEM and traditional FEA simulations it was demonstrated to provide additional accuracy. IBFEM was used to simulate a divertor monoblock mock up, where it was found that a region of delamination existed on the CFC Cu interface. Predictions showed that if this was aligned unfavourably it would increase thermal gradients across the component thus reducing lifespan. As this was a feature introduced in manufacturing it would not have been accounted for without IBFEM.The technique developed in this work has broad engineering applications. It could be used similarly to accurately model components in conditions unfeasible to produce in the laboratory, to assist in research and development of component manufacturing or to verify commercial components against manufacturers’ claims.