L’objectif principal de la thèse est d’analyser les mécanismes de plasticité et d’endommagement d’une nouvelle famille de composites à matrice acier Fe-TiB₂ afin de comprendre les liens microstructure/propriétés mécaniques et appliquer des modèles de comportement prenant en compte différents paramètres de la microstructure, et d’intérêt pour la mise en forme. L’étude porte sur des nuances de composites à teneur en particules fixée et différant par la taille de grain de la matrice. La caractérisation expérimentale des microstructures et textures initiales par MEB/EBSD et DRX a permis d’analyser qualitativement et quantitativement les différents paramètres morphologiques des renforts et de la matrice. L’effet de taille de grain de la matrice et des renforts sur l’écrouissage des ces composites a été étudié par essais de cisaillement simple monotone et inversés qui ont également permis de déterminer la part relative d’écrouissage cinématique des différents matériaux. L’application des résultats à une modélisation phénoménologique de l’écrouissage a permis de décrire le backstress des composites à partir de celui de la ferrite. L’analyse de l’évolution microstructurale avec la déformation de cisaillement, ainsi que des essais de flexion in situ, ont identifié la rupture des particules comme mode d’endommagement prépondérant des composites Fe-TiB₂. L’endommagement dépend de la taille de grain de la matrice, de d’endommagement des matériaux hétérogènes a permis d’estimer les contraintes de rupture des particules sur la base des résultats expérimentaux disponibles. / The aim of this work was the plasticity and damage mechanisms analysis of a new steel matrix composites Fe- TiB₂ family to establish the microstructure / mechanical properties relationships then interesting for metal forming simulations in respect with various microstructural parameters. The study was focused on composites with different matrix grain size and a given particle population. The experimental characterization of initial microstructures and textures with SEM/EBSD and XRD permitted the qualitative and quantitative analysis of different morphological parameters of reinforcements and the ferritic matrix. The effect of matrix grain size and reinforcements on the composites hardening is studied based on monotonous and reverse simple shear tests which leads to determine the relative contribution of kinematic hardening. The application of a phenomenological modeling based on these results, has successfully describe the composite backstress evolution. Analysis of the microstructural evolution with shear deformation and with four points bending situ tests has shown a sensitivity of Fe-TiB₂ damage to the matrix grain size, the particles size and to the strain-path change. A damage model of heterogeneous material has been then considered and provides the particles failure stress of on the basis of the available experimental results.

A popular concept in contemporary metaphysics is that of metaphysical simplicity - the idea that an existent can have no parts. One reason for this is that the notion of a simple is crucial to discussions of the composition of single objects. Simples, if real, are the basic units that, when combined in various ways, make up all other objects. Keith Campbell claims that tropes - particularized properties - can be simple. In this essay I argue, against Campbell, that tropes cannot be simple. They are made up of at least two parts - a bare particular and a universal. In Section 1 I give an exhaustive account of what it is to be a simple. Then in Section 2 I discuss basic particulars and what conditions must hold for a simple to be basic. Then in Section 3 I explain the nature of tropes and sketch out the parameters of Campbell's trope ontology. In Section 4 I argue that simple tropes actually have universal properties as parts. In Section 5 I give a logical argument to prove the correctness of the argument in Section 4. Then in Section 6 I take up several possible objections to my claim that tropes are not simple and argue that each one fails. Finally in Section 7 I conclude that tropes need to have an individuating component as a part and remark that tropes' location is not sufficient to be this component. My final claim is that tropes are not simple and they cannot be basic units in any robust sense.

Objetivos.- Conocer la prevalencia de la seropositividad para herpes virus I y II en pacientes con linfomas no hodking y su asociación con el linaje celular (B o T). Pacientes y Métodos.- Se tomó una muestra de 60 pacientes en el Hospital Almenara de Agosto de 1999 a Diciembre del 2000 todos ellos pacientes con diagnostico establecido de linfoma no hodking nuevos o en primera recaída, el análisis se realizo mediante bioestadística descriptiva. Resultados.- La mediana de la edad fue de 59 años, 2/3 fueron varones, 65% pacientes nuevos y el primario fue extraganglionar en un 58% de los casos. El 80% de los linfomas fueron a células B y más del 90% en estadios avanzados (III y IV), ningún caso fue positivo para IgM herpes I o II y 25% tuvieron serologia positiva para herpes I o II (2/3 positivos para IgG I) de los cuales más del 90% fueron a células B. Conclusiones.- La prevalencia de seropositividad para herpes virus I y II en pacientes con linfoma no hodking es del 25%, mayormente asociado a células B, además de tener un porcentaje considerable de linfomas a celulas T (25%) y linfomas extranodales (58%); para evaluar la posibilidad de asociación entre este virus y los linfomas requerimos de un estudio caso-control. / Objetives.- We intent to know the prevalence of seropositivity for herpes virus I and II in patients with malignant non hodking lymphoma (NHL), and the association with the cell lineage (B or T). Patients and Methods.- We considered 60 new or in first recurrence patients with NHL at the Almenara Hospital from August 1999 to December 2000, we analized the data by descriptive biostatistics in the Epi-Info program. Results.- The median age was 59 years, two thirds were men, 65% new patients and the primary site was extranodular in 58% of the cases. 80% were NHL to B cells, and more than 90% in advance stage (III and IV), none of them were positive for IgM herpes virus I or II and 25% were positive for IgG I or II (2/3 positive for IgG I) and more than 90% of them were for B cell, Conclusion.- The prevalence of seropositivity for herpes I or II in patients with NHL was 25%, usually associated to B cells, on the other hand we have an elevated percentage of T cell NHL (25%) as well as extranodulas NHL (58%). We need more studies specially a case-control study to define the association of herpes virus I or II with NHL.

In this dissertation, we study four methods for constructing codes and designs from finite groups. The first method was developed by Carmichael and Ernst in the nineteen thirty's. The second method is a generalization of the first one by D.R. Hughes in the nineteen sixty's. These first two methods use t-transitive groups to construct t-designs. The last methods arc two recent techniques developed by J .D. Key and J. Moori (2002). they use primitive finite groups to build l-designs. We will apply these methods to simple groups, and use the incidence matrix of the constructed designs to generate codes. / Thesis (Msc. in Mathematics) North-West University, Mafikeng Campus, 2013

No description available.

Dans cette thèse, nous étudions les effets des interactions électroniques dans le processus d'ionisation simple des cibles atomiques par impact des ions multichargés, ceux-ci peuvent être nus ou à demi vêtus. Dans le cas des projectiles nus, nous avons étudié l'interaction entre l'électron actif et les électrons passifs, la version post de l'approximation d'onde distordue du continu avec état initial eikonale est reformulé (CDW-EIS pour son sigle anglais), y compris un potentiel résiduel omis de calculs précédents. En addition, nous développons un modèle d'onde distordue de quatre corps pour l'ionisation simple des atomes diélectriques dans lequel les deux électrons sont considérés comme des actifs et à évoluer dans les mêmes temps. Dans le cas de considérer comme projectile des ions partiellement vêtus, nous étudions l'interaction électronique entre l'électron actif du cible et celles liées au projectile par l'élaboration d'un modèle d'onde distordue où le potentiel perturbatif du projectile est séparé en deux termes : une longue distance déterminée par la charge nette du projectile et autre à courte portée donnée par les électrons liés au projectile. Cette dernière est approchée par un potentiel paramétrique type GSZ (Green-Sellin-Zachor) / In this thesis the effects of the electronic interactions in the single ionization process of atoms by multiply charged ions impact are studied. The projectiles considered are either fully stripped or partially dressed ions. In the case of fully stripped ions we study the interaction between the target active electron and the passive electrons distribution, the post version of the CDW-EIS (Continuum Distorted Wave-Eikonal Initial State) approximation is revisited and a residual potential neglected in all previous calculations is considered. Also a four-body distorted wave model is developed to investigate the single ionization of dielectronic atoms where both electrons are considered as active ones and evolving in the same time-frame. When considering partially dressed ions as projectiles we investigate the interaction between the target active electron and those bound to the projectile by means of the extension of the CDW-EIS and CDW (Continuum Distorted Wave) models to the case where the projectile is a dressed ion. The projectile potential is described by a analytic parametric GSZ (Green-Sellin-Zachor) one that can be separated in two terms : a long range term determined by the net chargeof the totally screened projectile and a short range term due to the electrons bound to the projectile

This thesis contains methods of finding new presentations of finite groups, particularly nonabelian simple groups. We have presented several progenitors such as 2^{*8}:Z_4 wr Z_2, 3^{*3}:_m L(2,7), 2^{*4}:[2:2^2], 2^{*11}:D_{11} and many more on which we've found the mathieu group M12 and 2*[M21:2^2] among their homomorphic images. We give the full monomial automorphism groups of Aut(3^{*2}), Aut(3^{*3}), and Aut(5^{*2}). Included is a proof showing that the full monomial automorphism group of Aut(m^{*n}) is isomorphic to U(m) wr S_n. In addition we have constructed the Cayley Diagrams of PGL(2,7), [3 x A_5]:2, 3:[A_6:2], and 2 x [(3 x L(2,11)):2] using the process of double coset enumeration.

No description available.

No description available.

No description available.