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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 21 to 30 of 37 (0.179 seconds)| 21 |
Exceptional Properties in Friction Stir Processed Beta Titanium Alloys and an Ultra High Strength SteelTungala, Vedavyas 05 1900 (has links)
The penchant towards development of high performance materials for light weighting engineering systems through various thermomechanical processing routes has been soaring vigorously. Friction stir processing (FSP) - a relatively new thermomechanical processing route had shown an excellent promise towards microstructural modification in many Al and Mg alloy systems. Nevertheless, the expansion of this process to high temperature materials like titanium alloys and steels is restricted by the limited availability of tool materials. Despite it challenges, the current thesis sets a tone for the usage of FSP to tailor the mechanical properties in titanium alloys and steels. FSP was carried out on three near beta titanium alloys, namely Ti6246, Ti185 and Tiβc with increasing β stability index, using various tool rotation rates and at a constant tool traverse speed. Microstructure and mechanical property relationship was studied using experimental techniques such as SEM, TEM, mini tensile testing and synchrotron x-ray diffraction. Two step aging on Ti6246 had resulted in an UTS of 2.2GPa and a specific strength around 500 MPa m3/mg, which is about 40% greater than any commercially available metallic material. Similarly, FSP on an ultra-high strength steel―Eglin steel had resulted in a strength greater than 2GPa with a ductility close to 10% at around 4mm from the top surface of stir zone (SZ). Experimental techniques such as microhardness, mini-tensile testing and SEM were used to correlate the microstructure and properties observed inside SZ and HAZ's of the processed region. A 3D temperature modeling was used to predict the peak temperature and cooling rates during FSP. The exceptional strength ductility combinations inside the SZ is believed to be because of mixed microstructure comprised of various volume fractions of phases such as martensite, bainite and retained austenite.
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Le dispositif intégré DNL en français/cours de FOS et de FOU dans les FUF bi-plurilingues pour la réussite des étudiants allophones / A framework integrating non-linguistic subject(s) (DNL) in French and French for Specific Purposes (FSP)/French for Academic Purposes (FAP) courses in bi-multilingual French-language University Courses for success of allophone studentsBordo, Widiane 27 June 2016 (has links)
La mondialisation économique et l'internationalisation des échanges ont engendré l'ouverture des frontières et la mobilité professionnelle. Par conséquent, de nouveaux besoins communicatifs émergent. En effet, les institutions, les organismes, les administrations et les entreprises recrutent, aujourd'hui, des professionnels capables de communiquer en plusieurs langues lors de leurs activités professionnelles. Pour répondre à cette demande, des établissements scolaires et universitaires ont mis en œuvre des dispositifs d'enseignement bi-plurilingue. La présente thèse s'intéresse aux Filières Universitaires Francophones (FUF) bi-plurilingues, et a pour objectif d'analyser le dispositif Discipline(s) Non Linguistique(s) (DNL)/cours de français, censé garantir la réussite universitaire et professionnelle des étudiants allophones. Ainsi, nous avons mené une enquête de terrain au sein d'une FUF d'économie en Egypte pour y étudier les pratiques linguistiques et didactiques. Notre recherche montre que l'intégration d'un cours de Français sur Objectif Universitaire (FOU) et de Français sur Objectif Spécifique (FOS) dans le programme de formation des FUF vise la réussite des étudiants. Par ailleurs, les résultats de notre investigation nous ont conduite à élaborer différents outils permettant aux enseignants de français d'élaborer plus facilement des cours de FOS/FOU. Il s'agit précisément de la conception d'un référentiel de compétences langagières, d'un programme de formation de FOS/FOU et d'activités pédagogiques. / The economic globalization and internationalization of exchanges led to the opening of borders and professional mobility. As a result, new communication needs are emerging. Indeed, institutions, organizations, administrations and enterprises are nowadays recruiting professionals who can communicate in different languages during their workplace activities. To meet this demand, schools and universities have implemented bi-multilingual teaching. This thesis focuses on bi-multilingual French-language University Courses (FUF) and aims to analyze the framework including non-linguistic subject(s) (DNL) in French and French courses, which is intended to ensure the academic and professional success of allophone students. Thus, we conducted a field survey within the Economics courses of a FUF in Egypt so as to study the linguistic and teaching practices. Our research shows that the integration of French for Specific Purposes (FSP) and French for Academic Purposes (FAP) courses in the FUF’s academic program aims at student achievement. Furthermore, the results of our investigation led us to develop different tools which will enable French teachers to create FSP/FAP courses more easily. More specifically, it is the construction of a competency framework, the design of a training program and educational activities.
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Španělské determinanty este, ese, aquel a jejich české ekvivalenty / Spanish determiners este, ese, aquel and their Czech equivalentsErbenová, Adéla January 2015 (has links)
The thesis is focused on the Spanish determiners este, ese, aquel, the definite article and their anaphoric function. First, the theoretical groundwork for the latter analysis is built: the deter- miners are characterized together with the anaphora as a device of discourse coherence. Then, the choice between the demonstratives este, ese, aquel and the defi- nite article in different types of nominal anaphora is analyzed using examples from the parallel corpus InterCorp. Diverse factors influencing this choice are examined. The analysis is extended with a comparative analysis in which Czech equivalents of the Spanish determiners in the same types of anaphora are compared.
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Feasibility of Friction Stir Processing (FSP) as a Method of Healing Cracks in Irradiated 304L Stainless SteelsGunter, Cameron Cornelius 01 December 2016 (has links)
The current US fleet of nuclear reactors has been in service for three decades. Over this period, existing welds in stainless steel (SS) shrouds have sustained stress corrosion cracking (SCC) and are in need of repair. Additionally, helium has formed interstitially as a byproduct of proton bombardment. Current repair technology, such as TIG welding, puts extreme amounts of heat into the material and allows for interstitial helium atoms to aggregate and form bubbles/voids at grain boundaries. This significantly weakens the material, proving to be a very counterproductive and ineffective repair technique. Much study has been done on friction stir processing (FSP), but none has explored it as an enabling repair technology for use in nuclear applications. Because of its relatively low energy input as a solid state joining technology, it is proposed that FSP could effectively heal SCCs in these existing welds without the negative side effect of helium bubble formation. A spread of speeds and feeds were initially tested using a PCBN-W-Re tool on 304L SS. Six of these parameter sets were selected as representations of high, medium, and low temperature-per-power outputs for this research: 2 IPM-80 RPM, 2 IPM-150 RPM, 4 IPM-150 RPM, 4 IPM-250 RPM, 6 IPM-125 RPM, and 6 IPM-175 RPM. These varied parameter sets were tested for their tensile, micro-hardness, and corrosion resistant properties. In general, the lower IPM and RPM values resulted in higher ultimate tensile strengths (UTS). Higher IPM and RPM values resulted in tunnel, pin hole, and surface void defects. These defects caused premature failure in tensile tests and could often be identified through microscopy. Micro-hardness testing demonstrated a strong correlation per the Hall-Petch relationship – finer grain sizes resulted in higher yield strength (hardness values) of the material. The tool temperature during FSP was a good indicator of the expected hardness – lower temperatures resulted in higher hardness values. Corrosion testing was performed with a 1000-hour alternate immersion test in a room temperature 3.5% NaCl solution. With these testing parameters, the results demonstrated that FSP had no effect on the corrosion resistance of 304L SS under these conditions.
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Concevoir un programme de français sur objectifs spécifiques. Difficultés théoriques et pratiques : le cas de la faculté d'économie de l'Université Agostinho Neto Luanda-Angola / Create a program of French for Specific Purposes. Theorical and practical difficulties : the case of the economics faculty of the Agostinho Neto University, Luanda-AngolaZolana, Adolfo Ndomingiedi 07 February 2013 (has links)
Les recherches effectuées dans l’enseignement/apprentissage des langues vivantes et surtout dans le champ de la didactique des langues étrangères et secondes ont fait apparaître, depuis les années 20, des publics ayant des demandes spécifiques en communication professionnelle et fonctionnelle. Cette prise en compte des chercheurs a donné lieu à un domaine ouvert, varié, complexe, qui se caractérise par la grande diversité de ses contextes, situations d’enseignement, méthodes, objectifs, pratiques et dispositifs appelé le Français sur Objectifs Spécifiques. C’est dans le but de faire acquérir à ces publics des compétences culturelles et langagières spécifiques que, enseignants et chercheurs sont appelés aujourd’hui à se créer des démarches méthodologiques spécifiques. En s’inscrivant dans cette problématique, ce travail cherche à apporter des éléments de réponse aux demandes réelles des enseignants et des étudiants de français des universités angolaises plus particulièrement à celles de ceux de la faculté d’économie de l’université Agostinho Neto. L’objectif principal est donc, d’une part, d’identifier les besoins réels de ces derniers en prenant en compte les spécificités de leurs filières de formation et d’autre part, de concevoir, au cas par cas, des programmes et du matériel didactique permettant de développer chez les apprenants les compétences de compréhension et d’expression tant orales qu’écrites. Ces matériaux conçus à partir de documents authentiques à visée professionnelle oraux ou écrits sont susceptibles d’être directement utilisés en classe pour les enseignants qui voudront les transférer ou les réutiliser dans des situations similaires. / Research performed since the twenties in teaching/learning of the living languages, especially in the field of didactics of foreign and second languages, helped the rise of a certain audience with specific requests in professional and functional communication. This consideration of the researchers gave rise to an opened, varied, complex domain, which is composed of an important diversity of contexts, learning situations, methods, objectives, practices and structures of formation called "French for Specific Purposes". Teachers and researchers are brought today to create specific methodological approach, to help this audience gain specific cultural and linguistic skills. Within this problematic, this research aims at bringing elements of answer to the teachers and the french students of the Angolan universities, particularly to those of the Faculty of Economy of the Agostinho Neto University. Therefore, our purpose is to identify the real needs of the latter, taking into account peculiarities of their study paths and indeed to conceive programs and teaching tools, allowing them to develop oral and written comprehension and expression skills. These materials, made from “authentic oral or written documents with professional aim”, can be used directly in class by teachers who may want to reuse them in similar situations.
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Iniciální pozice rématu v angličtině. / Initial rheme in English.STÁHALÍK, Martin January 2014 (has links)
This diploma thesis analyses instances of the initial position of the information focus, the rheme, in present-day English. Initial placement of the rheme is found in structures that go against the principle of end-focus. The aim of this work is to identify which clause constituents, and under what circumstances may function as the initial rheme. The initial section of the theoretical part deals with a description of word-order, and the basic concepts of functional sentence perspective, such as communicative dynamism. Then it continues with the rheme and the factors affecting FSP, and, particularly, with cases where initial rheme occurs. The practical part contains analysis of examples of initial rheme in different genres and text types, including oral communication. The frequency of occurrence is summarized at the end of the work.
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Capillary pore-size distribution and equilibrium moisture content of wood determined by means of pressure plate techniqueZauer, Mario, Meissner, Frank, Plagge, Rudolf, Wagenführ, André 23 June 2020 (has links)
This paper deals with the determination of the capillary pore-size distribution (CPSD) and equilibrium moisture content (EMC) of untreated and thermally modified (TM) Norway spruce [Picea abies (L.) Karst.] by means of the pressure plate technique (PPT). Desorption experiments were conducted at very high values of relative humidity (RH) in the range between 99.2% and 100%. The thermal modification of spruce results in an alteration of the CPSD, owing to the formation of intercellular cracks in the middle lamella, as a result of cell-wall compression. The desorption curves for both untreated and TM spruce show an extremely upward bend at 99.97% RH. This step reflects an EMC of 38.1% for untreated spruce and 33.8% for TM spruce. None of the samples shrunk during the PPT measurements. Following desorption experiments at 97.4% RH, all samples shrunk. This step reflects an EMC of 27.9% for untreated spruce and 21.7% for TM spruce.
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Syntaktické, sémantické a aktuálněčlenské aspekty ditranzitivni komplementace: analýza sloves blame a provide / Syntactic, semantic and FSP aspects of ditransitive complementation: a study of blame and provideBalcarová, Adéla January 2013 (has links)
The present thesis is concerned with the syntactic, semantic and FSP aspects of ditransitive complementation. All these aspects are discussed not only theoretically, but mainly practically in an analysis of two ditransitive verbs: blame and provide. For the purpose of the present analysis, 200 sentences (100 for each of the analyzed verbs) were excerpted from the British National Corpus. The analyzed verbs enter into two possible sentence structures. The first construction includes a subject and verb as well as a direct object and a prepositional object (SVOdOprep); the alternative construction includes a subject and verb as well as an indirect object and a prepositional object (SVOiOprep). One of the points of analysis is a quantitative formulation of the number of occurrences of each of the respective sentence structures for the analyzed verbs within the excerpted material. Within the ditransitive construction we may sometimes encounter object omission of either of the objects (more commonly the indirect object). The analysis concentrates on the possibilities of object omission within ditransitive constructions with the two analyzed verbs. Part-of-speech representation of both objects is also a matter of analysis; there are altogether four possible part-of-speech patterns depending on whether...
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Vers une ingénierie de formation pour le français du tourisme en contexte marocain / A training engineering for French of tourism in the Moroccan contextBenmoussa, Saâdia 02 February 2017 (has links)
Si la langue française fut imposée, à l'époque coloniale à des fins d'empire et d'emprise, actuellement, elle s'impose par l'effet de la mondialisation comme une langue à visée professionnelle. Notre recherche accorde une attention particulière à l'enseignement du français à visée professionnelle dans le domaine du tourisme au Maroc. Elle se situe donc au carrefour de la didactique des langues et de la formation professionnelle initiale, suite aux programmes d'urgence décidés récemment par le Ministère du tourisme marocain concernant la mise à niveau des étudiants en français. Le besoin de réagir de manière efficace est devenu particulièrement sensible et motive la présente recherche. Notre projet est d'une part, de faire l'état des lieux de l'enseignement du français dans le domaine du tourisme au Maroc depuis l'indépendance à aujourd'hui, en examinant les outils méthodologiques utilisés, et, d'autre part, d'identifier les besoins actuels des apprenants et des enseignants et plus largement, les attentes des établissements touristiques, afin de concevoir un matériel didactique du français spécialement destiné à notre public actuel. L'objectif est de faire acquérir aux apprenants des compétences culturelles et langagières spécifiques, tant orales qu'écrites répondant aux injonctions du marché de l'emploi-En cela, le domaine de l'ingénierie de formation sera sollicité. / Back In the colonial era, French language was imposed for empire and influence purposes, yet nowadays, it stands as a language for professional purpose due to the impact of globalization. My research pays particular attention to the teaching of French for professional purpose in the field of tourism in Morocco. This research comes as an intersection between language didactics and initial vocational training, following the emergency programs recently decided by the Moroccan Ministry of tourism about upgrading French language level among students. Thus, the need to respond effectively has become particularly sensitive and is a strong motive for this research. This project is based on an appraisal of French teaching regarding tourism in Morocco altogether with reviewing used instruments for this purpose in one hand, and figuring out students and teachers current needs and even touristic institutions expectations in the other hand, in order to perceive didactical French appliances mainly intended to our present public. In fact, the intention is to pump some specific cultural and lingual proficiency whether it's written or oral, that meets the work market needs. For this purpose, training engineering is highly recommended.
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SCALABLE AND FAULT TOLERANT HIERARCHICAL B&B ALGORITHMS FOR COMPUTATIONAL GRIDSBendjoudi, Ahcène 24 April 2012 (has links) (PDF)
La résolution exacte de problèmes d'optimisation combinatoire avec les algorithmes Branch and Bound (B&B) nécessite un nombre exorbitant de ressources de calcul. Actuellement, cette puissance est offerte par les environnements large échelle comme les grilles de calcul. Cependant, les grilles présentent de nouveaux challenges : le passage à l'échelle, l'hétérogénéité et la tolérance aux pannes. La majorité des algorithmes B&B revisités pour les grilles de calcul sont basés sur le paradigme Master-Worker, ce qui limite leur passage à l'échelle. De plus, la tolérance aux pannes est rarement adressée dans ces travaux. Dans cette thèse, nous proposons trois principales contributions : P2P-B&B, H-B&B et FTH-B&B. P2P-B&B est un famework basé sur le paradigme Master-Worker traite le passage à l'échelle par la réduction de la fréquence de requêtes de tâches et en permettant les communications directes entre les workers. H-B&B traite aussi le passage à l'échelle. Contrairement aux approches proposées dans la littérature, H-B&B est complètement dynamique et adaptatif i.e. prenant en compte l'acquisition dynamique des ressources de calcul. FTH-B&B est basé sur de nouveaux méchanismes de tolérance aux pannes permettant de construire et maintenir la hiérarchie équilibrée, et de minimiser la redondance de travail quand les tâches sont sauvegardées et restaurées. Les approches proposées ont été implémentées avec la plateforme pour grille ProActive et ont été appliquées au problème d'ordonnancement de type Flow-Shop. Les expérimentations large échelle effectuées sur la grille Grid'5000 ont prouvé l'éfficacité des approches proposées.
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