Thesis (Ph.D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed on Sept 9, 2009). Includes bibliographical references (p. 120-125).

Made available in DSpace on 2014-06-11T19:26:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-22Bitstream added on 2014-06-13T20:08:00Z : No. of bitstreams: 1 sacramento_aj_me_sjrp.pdf: 3231856 bytes, checksum: 0136158c9dd1d9766f0bd327e206e676 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho é estudar a equivalência de contato topológica dos germes de aplicações diferenciáveis tendo como plano de fundo o estudo da equivalência de contato clássica (ou C∞-K-equivalência). Neste sentido, apresentamos inicialmente uma análise detalhada sobre alguns invariantes e propriedades clássicas da equivalência de contato e, em seguida, introduzimos o estudo da versão topológica desta relação de equivalência. A equivalência de contato topológica (ou C0-K-equivalência) é um tema que recentemente ganhou o interesse de vários pesquisadores por se tratar de uma relação de equivalência cujos invariantes, propriedades e classi cações são pouco conhecidos ou inexistentes. Sob esta ótica, investigamos se alguns invariantes encontrados no caso clássico poderiam ser reproduzidos ou adaptados para o caso topológico. Como parte principal do trabalho, apresentaremos um invariante completo para a equivalência de contato topológica introduzido por T. Nishimura [22]. Este invariante é dado para germes de aplicações nitamente determinadas cujas dimensões da fonte e da meta coincidem / The goal of this work is to study the topological contact equivalence of smooth map germs having as background the study of the classical contact equivalence (or C∞-Kequivalence). In this sense, we rstly present a detailed analysis of some invariants and classical properties of the contact equivalence, and then we introduce the study of the topological version of this equivalence relation. Recently several researchers have been interested in this subject because it is an equivalence relation whose invariants, properties and classi cations are unknown or nonexistent. In this work we investigate if some invariants of contact equivalence could be reproduced or adapted for the topological case. In chapter 3 we present a complete invariant for the topological contact equivalence introduced by T. Nishimura [22]. This invariant is given to nitely determined map germs whose dimensions of the source and target are equal

L'objectif du travail présenté dans ce mémoire de thèse est d'évaluer par des mesures les champs de pression, de déformation et de contraintes induits par un contact élastique localisé entre deux pièces mécaniques. Après avoir exploré les différentes méthodes existantes, un constat a été fait : la grande majorité des techniques de mesure passent par l'évaluation de grandeurs physiques seulement indirectement liées aux grandeurs recherchées. En cherchant une approche plus directe, l'idée de caractériser la déformation de la surface de contact entre deux pièces a permis de trouver un moyen de mesure : la microscopie confocale chromatique. Ainsi, en mesurant, cette surface, par transparence, et en utilisant la théorie des potentiels de Boussinesq et Cerrutti, il a été possible d'une part de calculer le champ de pression au contact entre les pièces mais aussi d'évaluer les autres champs élastiques associés. Cette approche a aussi permis de mettre au point une méthode de simulation de contact localisé originale et performante s'appliquant à toute géométrie de contact. / The aim of this thesis is to evaluate pressure, strain and stress fields induced by a localized contact between mechanical parts. As the different methods have been explored, it appeared that all existent methods just measure physical quantities only indirectly related to the data of interest. By searching a more direct method, the idea of characterizing the deformation of the surface of contact between parts allowed to find a way of measurement: chromatic confocal microscopy. Thus, measuring this surface by transparency and using Boussinesq and Cerrutti potential theory allows first to calculate the pressure field at the contact between the parts but also to evaluate the other associated elastic fields. This approach also helped to develop an original and highly simulation method of localized contact applying to any contact geometry.

The striking similarities between Old English (OE) and its neighbour Old Frisian (OFris)—including aspects of phonology, morphology, and alliterative phrases—have long been cause for comment, and often for controversy. The question of whether the resemblance was caused by an immediate common ancestor (Anglo-Frisian) or by neighboring positions in a dialect continuum/Sprachkreis has been hotly disputed using phonological and toponymic evidence, but not in recent years. Consensus in the nineties fell in favour of the dialect continuum, and there the issue has largely rested. However, recent finds in archaeology, history, and genetics argue that the case requires a second look. Developments in grammaticalization theory and contact linguistics give us new tools with which to investigate. Are the similarities between OE and OFris due to an exclusive shared ancestor, or are those languages merely part of a dialect continuum, with no closer relationship than that shared with the other early West Germanic dialects? And are there any reliable criteria to separate out inheritance-based similarities from those that are spread by contact? Shared developments seem, primo facie, to be evidence of shared inheritance, but there are other possible explanations. Parallel drift after separation, convergent development, or coincidence might be the cause of any shared feature. In this paper, I discuss recently proposed methods of distinguishing inheritance from drift and contact, focusing on how morphosyntax can help explore the shared history of OE and OFris. While grammaticalization processes often lead to cross-linguistic similarities, the fact that OE and OFris display a cluster of grammaticalizations not found in other early West Germanic dialects may be significant. The exclusive developments under investigation include aga(n) ‘have’ > ‘have to’ and the present participle as verbal complement. By comparing the forms, meanings, and distribution of these grammaticalized forms in the OFris corpus to that of their cognate forms in OE, I show that the two languages probably diverged from one another substantially later than they diverged from Old Saxon and Old Low Franconian.

La réduction des dimensions des dispositifs et les limites atteintes par la lithographie pour les nœuds technologiques sub-20nm requièrent l’introduction d’un « double patterning » pour définir les contacts. Le masque final est défini par l’intersection d’un masque dur en TiN et d’un masque organique (OPL) et est utilisé pour transférer les motifs des contacts par gravure plasma dans une couche de diélectriques (SiO2/Si3N4). Par rapport aux nœuds technologiques précédents, cette architecture entraine de nouvelles problématiques dues à l’intégration du double patterning et du masque dur en TiN.Cette thèse porte sur la gravure des contacts définis par « double patterning » pour la technologie 14 nm FDSOI (Fully Depleted Silicon On Insulator) à STMicroelectronics. Plus particulièrement, l’objectif principal de ce travail de thèse a été d’évaluer l’effet des masques d’OPL et de TiN sur la gravure des contacts en termes de contrôle dimensionnel (CD) et de profil de gravure. Dans cet objectif, nous avons comparé deux procédés de gravure de l’OPL à base de N2/H2 ou de COS/O2 et leur impact sur le transfert des contacts. Un autre objectif de ce travail de thèse a été consacré à la compréhension et à la limitation du phénomène de croissance de résidus métalliques après le procédé de gravure des contacts. Ceci est obtenu notamment à travers le développement de traitements plasma post gravure. Pour déterminer les mécanismes d’interactions entre les plasmas du procédé de gravure des contacts et les matériaux des masques, des analyses de la surface des matériaux exposés aux plasmas ont été réalisées par des techniques telles que l’XPS et l’EDX et des analyses de la phase gazeuses du plasma ont été réalisées par spectroscopie d’émission optique (Optical Emission Spectroscopy – OES). Nous avons montré que les profiles des contacts étaient influencés par le procédé de l’étape d’ouverture de l’OPL et particulièrement à travers l’interaction des plasmas et du masque dur en TiN. Cette interaction peut conduire à une modification de la forme du masque dur en TiN et au redépôt de composés métalliques peu volatils sur la plaque et sur les parois du réacteur au cours du procédé de gravure. Ceci peut conduire à une déformation des profils et à un quasi-arrêt de la gravure pendant la gravure des matériaux diélectriques. Par ailleurs, nous avons montré que l’efficacité des traitements à base de méthane pour ralentir ou éviter la croissance de résidus à la surface du TiN après la gravure des diélectriques peut être améliorée par un contrôle de l’état des parois de la chambre au cours du traitement, en effectuant un nettoyage de la chambre en oxygène avant l’application du traitement. / Due to the reduction of the transistor dimensions and the limitations of the lithography to define small contact patterns for the sub-20nm technological nodes, the introduction of double patterning strategies is required for contact patterning. In such architectures, the final mask is defined by the combination of a TiN hard mask and an organic (OPL) mask, which defines the contact patterns that will be transferred into the underlying dielectric layers (SiO2/Si3N4). This leads to new challenges for contacts definition, especially because of the integration of double patterning strategies and TiN hard masks which were not present for previous technologies.This study addresses the contact etching process using a double patterning strategy for the 14 nm Fully Depleted Silicon on Insulator (FDSOI) technology. More particularly, the main goal of this work was to evaluate the impact of both TiN and OPL masks on the contact patterning process in terms of dimensions and profiles control. For this, we have compared two different OPL etch processes (N2/H2 and COS/O2) and their impact in the contact pattern transfer in the dielectric layers. In addition, this work was also dedicated to the understanding and limitation of metallic residues growth occurring after the contact etch process. This is carried out especially through the development of post etch plasma treatments.We performed XPS and EDX analyses to determine the mechanisms involved in the interactions between plasma processing steps and the masking materials (TiN, OPL). The plasma gas phase was also analyzed by Optical Emission Spectroscopy (OES).We show that the contact etch profile is influenced by the OPL etching process due to the interactions between the plasma and the TiN hard mask. These interactions may lead to a modification of the hard mask profile and are at the origin of the metallic contamination observed over the patterned wafer or the reactor walls. Due to this contamination, the contact profiles are deformed and the dielectric etch process may be stopped. Finally, we have shown that the state-of-art CH4-based post-etch-treatments introduced to limit the residues growth after dielectric patterning with a TiN mask can be improved by adding an oxygen-based reactor cleaning process before the post-treatment process.

La diffusion de l'anglais peut être associée à de nombreux facteurs historiques mais elle relève aussi de la rencontre de la langue avec des phénomènes mondiaux. Ainsi, l'anglais a acquis un statut de langue globale sans précédent. Les évolutions de la configuration linguistique mondiale soulèvent de nombreuses questions sur l'avenir des langues en général et celui de l'anglais en particulier. La diffusion de l'anglais dans le monde n'est pas un phénomène homogène et elle relève de processus complexes générés par la rencontre de la dimension globale et locale. La thèse soutenue prend appui sur cet aspect fondamental pour montrer, à travers le cas de l'Algérie, que la diffusion de l'anglais dépend de la configuration sociolinguistique de son environnement d'implantation d'un point de vue quantitatif et qualitatif. L'environnement algérien compte deux langues d'envergure internationale - l'arabe et le français - qui jouent un rôle important dans la distribution des langues au niveau national. Par ailleurs, l'histoire de l'Algérie, son héritage colonial et les politiques d'arabisation appliquées dans le pays ont forgé une culture linguistique qui influence la dimension symbolique de la diffusion de l'anglais dans le contexte algérien. Une enquête de terrain menée dans les universités d'Oran et de Mascara a permis d'évaluer les attitudes linguistiques d'un groupe d'étudiants et de montrer que la langue globale n'est pas dénuée d'une certaine valeur symbolique qui favorise sa diffusion. / The spread of English can be associated with many historical factors, but it also finds its roots in the meeting of the language with global phenomena. Thus, English has become a global language with an unprecedented status. The modern developments in the global linguistic situation raise many questions about the future of languages in general and English in particular. The spread of English in the world is not a homogeneous phenomenon and falls within complex processes generated by the meeting of the global and local dimensions. The present thesis relies on this fundamental aspect to show, through the case of Algeria, that the spread of English depends on the sociolinguistic environment in which it is implemented, from a quantitative and qualitative perspective. The Algerian environment has two major international languages ​​- Arabic and French - that play an important role in the distribution of languages​​ at a national level. Moreover, the history of Algeria, its colonial heritage and the language policies in the country have forged a linguistic culture that influences the symbolic dimension of the spread of English in the Algerian context. A fieldwork conducted in universities of Oran and Mascara enabled to assess the languistic attitudes of a group of students and show that the global language is not devoid of a symbolic value that favors its spread.

A Resistência Térmica de Contato entre a ferramenta de forjamento e a peça é um parâmetro importante para a otimização, por simulação computacional, do comportamento do material forjado. Os procedimentos atuais destinados à determinação da Resistência Térmica de Contato apresentam discrepância significativa nos resultados. A falta de valores confiáveis deste parâmetro afeta a precisão da simulação. Visando a importância das ferramentas computacionais para a otimização do processo de forjamento, no presente trabalho foi desenvolvida uma nova técnica para determinar a Resistência Térmica de Contato. A técnica inovadora inclui o método de medição de temperaturas interfaciais desconhecido anteriormente, a montagem para realizá-lo e o sistema de medição de temperaturas volumétricas. Esta técnica é destinada ao uso sob condições de altas e moderadas temperatura e pressão muito grande, o que é característico da zona de contato material forjado–ferramenta. A inovação foi testada com sucesso para alguns materiais típicos (aço, liga de alumínio e liga de titânio) utilizados no forjamento a quente ou a morno. Os valores da Resistência Térmica de Contato, obtidos nos testes, são recomendados para uso em programas de simulação computacional. / The Thermal Contact Resistance between a die and a blank is an important parameter in the computer simulation used for the optimization of the blank plastic deformation. The known procedures intended for the determination of the Thermal Contact Resistance show significant discrepancy in results. The lack of reliable values of this parameter affects the precision of the simulation. Taking in account the importance of computer tools for the optimization of the forging process, a new technique for the determination of the Thermal Contact Resistance has been developed in the present study. The developed technique includes a method for the measurement of the interface temperatures, which was unknown before, and the equipment for the realization of this method as well as the system for the measurement of the volumetric temperatures. This technique is intended for use under moderate and high temperature / high pressure conditions at the die–workpiece interface. The innovation has been tested successfully on some typical materials (steel, aluminium alloy e titanium alloy) used in warm and hot forging. Values of the Thermal Contact Resistance obtained by these tests are recommended for use in computer simulations.

The thesis provides a corpus-based study of the development of Irish English modal verbs from the fourteenth to the twentieth centuries in comparison to mainland English. More precisely, it explores the morpho-syntax of CAN, MAY, MUST, SHALL and WILL and the semantics of BE ABLE TO, CAN, MAY and MUST in the two varieties. The data of my study focuses on the Kildare poems, i.e. fourteenth-century Irish English religious poetry, and a self-compiled corpus consisting of personal letters, largely emigrant letters, and trial proceedings from the late seventeenth to the twentieth centuries. The analysis of the fourteenth and nineteenth centuries is further compared to a similar corpus of English English. The findings are discussed in the light of processes associated with contact-induced language change, new-dialect formation and supraregionalization. Contact-induced language change in general, and new-dialect formation in particular, can account for the findings of the fourteenth century. The semantics of the Irish English modal verbs in this century were mainly conservative in comparison to English English. The Irish English morpho-syntax showed an amalgam of features from different dialects of Middle English in addition to some forms which seem to be unique to Irish English. The Irish English poems recorded a high number of variants per function in comparison to a selection of English English religious poems, which does not conform to predictions based on the model of new-dialect formation. I suggest that this might be due to the fact that the English language had not been standardized by the time it was introduced to Ireland, and thus the need to reduce the number of variants was not as great as it is suggested to be in the post-standardization scenarios on which the model is based. In seventeenth- and eighteenth-century Ireland, increased Irish/English bilingualism caused the formation of a second-language (L2) variety of English. In the nineteenth century the bilingual speakers massively abandoned the Irish language and integrated into the English-speaking community. As a result, the varieties of English as spoken by the bilingual speakers and as spoken by the monolingual English speakers blended and formed a new variety altogether. The use of modal verbs in this new variety of Irish English shows signs of colonial lag (e.g. in the development of a deontic possibility meaning for CAN). Additionally, the subtle differences between BE ABLE TO and CAN in participant-internal possibility contexts and between epistemic MAY and MIGHT in present time contexts were not fully acquired by the L2 speakers, which resulted in a higher variability between the variants in the new variety of Irish English. In the late nineteenth and early twentieth centuries the use of modal verbs converged on the patterns found in English English, either as a result of linguistic accommodation in the case of informants who had migrated to countries such as Australia and the United States, or as a result of supraregionalization in the case of those who remained in Ireland.

Les balais de démarreurs utilisent un mélange de graphite et de cuivre pour assurer la transmission du courant électrique dans un contact glissant. La densité de courant qu'ils subissent peut atteindre 300A et la vitesse de glissement 20m/s. Ces contraintes très sévères entrainent une usure rapide de ces balais. La conséquence directe est un nombre de cycles insuffisant face au nombre accru demandé par les consommateurs, notamment avec l'introduction de la fonctionnalité stop-start qui augmentent d'une façon brutale le nombre de démarrage d'un démarreur. Le but de la thèse est de comprendre le mécanisme d'usure de ces balais métal-graphite via la modélisation numérique et des essais expérimentaux réalisés sur un banc tribomètre. La compréhension passe au niveau général d'un milieu continu homogène discrétisé par des éléments discrets jusqu'à un mélange d'élément entre cuivre et graphite, pour avoir une appréciation plus approfondie du mode d'usure notamment concernant les deux éléments présents cuivre et graphite, en essayant de chercher une composition optimale. / We study the tribological behavior of brush-commutator contact for electrical starters. Such contact composed of metal-graphite brushes and a copper commutator is under extremely severe electrical and mechanical sollicitations during starting cycles. The direct impact of this is an insufficient number of cycles for stop-start applications before failure. Our goal is to study the effect of electrical current on the tribological behavior of the contact system using enhanced Discrete Element Method. The mechanical, electrical and thermal behaviors are computed for a elementary representative volume of contact system. The simulation results showed the impact of Joule heating on tribological behavior of contact accelerate the wear process of contact, suggesting a better brush material with better electrical conductivity, leading to the study of the impact of metal content on tribological behavior of contact, since metal elements can improve significantly the electrical conductivity of brush material.

La présente étude porte sur l'utilisation des forces de tension de surface créées par une mouillabilité hétérogène afin de faciliter l'évacuation des gouttes. La mouillabilité hétérogène de la surface solide permet le déséquilibre mécanique au niveau de la ligne triple des embryons de gouttes se formant à la paroi, entraînant ainsi leur déplacement. Théoriquement, l'hystérésis d'angle de contact a été négligée dans la plupart des études mettant en œuvre des gradients de mouillabilité, mais identifié comme ayant un rôle important sur le mouvement. Nous avons développé par conséquent un modèle dynamique qui prend en compte explicitement l'hystérésis d'angle de contact et une comparaison avec des données expérimentales de la littérature a été effectuée. Le transfert de masse a été par la suite ajouté à ce même modèle pour comprendre l'effet d'un gradient de mouillabilité sur les transferts de chaleur en régime de condensation en gouttes. L'analyse quantitative des résultats théoriques montre que l'hystérésis réduit fortement les vitesses de déplacement de la gouttelette. De plus, il a été montré que les transferts sont nettement plus intenses dans la phase de croissance que pendant la phase dynamique. L'intérêt consiste donc à réduire au maximum la taille de la goutte évacuée afin de permettre à la fois une densité et fréquence élevée de nucléation. Parallèlement à cette approche théorique, un dispositif expérimental a été développé pour étudier la condensation de la vapeur d'eau sur une surface avec gradient de mouillabilité. Les résultats expérimentaux ont mis en évidence la faculté du gradient de mouillabilité à maintenir un régime de condensation en gouttes plutôt qu'un régime en film. L'occurrence de la nucléation et du grossissement de gouttes de petites dimensions, phase durant laquelle les transferts de chaleur sont importants, est largement favorisée par une évacuation rapide des gouttes. / The present work deals with the use of surface tension forces induced by heterogeneous wettability to solve this problem. It is considered that heterogeneous wettability of a solid surface enables the mechanical non-equilibrium of the drop embryos forming at the wall. Theoretically, contact angle hysteresis has been neglected in most of the studies about wettability gradients but recently found to be a major phenomenon deserving attention. Therefore, we developed a dynamic model that explicitly takes into account the contact angle hysteresis. Results of this model were compared with experimental data found in the literature. Subsequently mass transfer was added to this same model in order to understand the effect of a wettability gradient on heat transfer during dropwise condensation process. Quantitative analysis of the results showed that the theoretical hysteresis greatly reduced the droplet velocity. In addition, the model identified the importance of spatial heterogeneities of contact angle hysteresis on the dynamic behavior of the drop. Finally the heat transfers during the growth phase proved to be much more intense than during the dynamic phase. The interest is therefore to minimize the size of the droplet removed to enable both high density and nucleation frequency. The theoretical results analysis showed that such surface energy gradient enhances the transfers. Simultaneously with this theoretical approach, an experimental setup has been developed to study the effects of wettability surfaces when water vapor condensation occurs. Experimental results revealed the ability of wettability gradient to maintain a dropwise condensation regime rather than a filmwise regime. The occurrence of nucleation and growth of small droplets, that involve important heat transfer rate, is widely promoted by the fast droplet removal.