The beginnings of metallurgical activity have intrigued scholars for decades. In this dissertation, I explore early metallurgical activity on the Iranian Plateau represented by the evidence at Tal-i Iblis in southern Iran, and Seh Gabi and Godin Tepe in central northern Iran. Together, these sites offer a diachronic view of metal production on the Plateau as well as a view of metallurgical activities practiced at different scales of production. The metallurgical materials from Tal-i Iblis are firmly dated to the late 6th to early 5th millennia BCE, and this corpus includes hundreds of crucible fragments excavated from multiple trash dumps. Seh Gabi and Godin Tepe offer a smaller range of production materials from the 4th through 2nd millennia BCE, but they also include a large collection of finished metal objects. These later materials differ in style and process from the Iblis debris.Thorough examination of these artifacts, combined with comparison to a series of carefully controlled casting experiments, has returned numerous significant results. The metallurgy of the Iranian Plateau does not fit the standard model of early metallurgical development. The Iblis crucibles do not reflect an early "experimental" stage in copper production. Rather, these artifacts represent a carefully controlled, production process with a narrow range of variability in both temperature and reducing atmosphere. Further, there is clear evidence for the preference of arsenical-copper alloys at Tal-i Iblis. These ancient craftspeople sought high-quality ores from a source (the Talmessi copper deposit) over 500 km from their production facility.Metallurgical production on the Iranian Plateau is also characterized by the long-term use of crucibles as the primary reaction vessel well into the 2nd millennium BCE. There are some production centers on the Iranian Plateau that see the use of furnaces during the 3rd millennium, but crucible use persists at many sites. At Godin Tepe--a site with significant evidence for contact with the Mesopotamian lowlands--variability in crucible form increases in later periods to include an Egyptian-style crucible during the 2nd millennium BCE. The presence of this crucible suggests that there was contact with foreign metallurgical processes, but the preference for small, portable reaction vessels persisted.

A Espada de Damasco era uma arma utilizada pelos exércitos muçulmanos medievais. Está de tal forma associada à civilização islâmica que se tornou um de seus símbolos. Esta espada se caracterizava tanto por suas ótimas propriedades mecânicas como por seus belos desenhos ondulados. Estes atributos, somados à sua mística, a fizeram objeto de imitação e cobiça no Ocidente. Entre os séc. VIII e XIII d.C. o mundo muçulmano viveu seu apogeu como civilização, compilando, traduzindo, analisando e desenvolvendo um enorme corpo de conhecimento, em diversas áreas, trazido das grandes civilizações com as quais interagiu. No campo militar, as invasões dos povos nômades da Ásia Central trouxeram inovações, sendo claramente responsáveis pela introdução do sabre. O Império muçulmano medieval reuniu, assim, as condições necessárias para o advento da Espada de Damasco, principalmente por ter absorvido de outros povos, tanto a oeste, como a leste, uma série de elementos e influências fundamentais para a concepção desta arma: seu formato, o sabre, foi trazido pelos povos turcomanos nômades, e a tecnologia do aço de cadinho, sua matéria prima principal, era proveniente do Oriente; da Índia e da Ásia Central. Este trabalho se propõe a discutir de que forma a lendária Espada de Damasco pode ser entendida como um produto único da civilização islâmica medieval. Para alcançar este propósito, duas das principais características desta arma serão discutidas, seu formato como sabre, e sua matéria prima, o aço de cadinho. Finalmente, a etapa experimental realizada nos permite avaliar sob nossa própria perspectiva as duas principais hipóteses para explicar a formação do padrão de damasco, propostas por Verhoeven e Sherby. Além disso, as tentativas de reprodução do aço de cadinho nos levam a propor a hipótese do ferro fundido, invenção sabidamente chinesa, ter sido descoberto de forma acidental ao tentar produzir aço de cadinho. / The Damascus sword was the weapon of choice of the Muslim medieval armies. It is so closely related to the Islamic civilization that it became one of its symbols. This saber was known by its great mechanical properties, as much as its pleas-ant wavy pattern. All these attributes, added to its mystical meaning, turned it into an object to be reproduced and desired by the West. Between the 9th and 13th centuries AD, the Muslim society experienced its height as civilization, compiling, translating, analyzing and developing a wide body of knowledge of many fields, imported from the main civilizations with whom it coexist-ed. On military matters, nomadic peoples from central Asia invaded the Islamic world, bringing innovations with them, such as the saber. The Muslim medieval Empire pro-vided suitable conditions to allow the Damascus sword to be created. Specially, be-cause this civilization assimilated several influences from East and West, essential to the development of this weapon: its shape as saber was taken from the nomadic Turkic peoples, the technology of the crucible steel came from the East; Central Asia and India. This thesis discusses how the legendary Damascus sword may be understood as a unique product of the medieval Islamic civilization. Two of the most important features of this weapon will be discussed in order to reach our purpose: its design as a saber, and its raw material, the crucible steel. Finally, the experimental part allow us to assay, through our own perspective, the two main hypothesis what explain the origin of the Damascus pattern, suggested by Verhoeven and Sherby. Moreover, the different attempts to reproduce the UHC crucible steel lead us to formulate a hypothesis on the origin of the cast iron, a known Chinese invention, which could have been discovered by accident while trying to produce crucible steel.

A Espada de Damasco era uma arma utilizada pelos exércitos muçulmanos medievais. Está de tal forma associada à civilização islâmica que se tornou um de seus símbolos. Esta espada se caracterizava tanto por suas ótimas propriedades mecânicas como por seus belos desenhos ondulados. Estes atributos, somados à sua mística, a fizeram objeto de imitação e cobiça no Ocidente. Entre os séc. VIII e XIII d.C. o mundo muçulmano viveu seu apogeu como civilização, compilando, traduzindo, analisando e desenvolvendo um enorme corpo de conhecimento, em diversas áreas, trazido das grandes civilizações com as quais interagiu. No campo militar, as invasões dos povos nômades da Ásia Central trouxeram inovações, sendo claramente responsáveis pela introdução do sabre. O Império muçulmano medieval reuniu, assim, as condições necessárias para o advento da Espada de Damasco, principalmente por ter absorvido de outros povos, tanto a oeste, como a leste, uma série de elementos e influências fundamentais para a concepção desta arma: seu formato, o sabre, foi trazido pelos povos turcomanos nômades, e a tecnologia do aço de cadinho, sua matéria prima principal, era proveniente do Oriente; da Índia e da Ásia Central. Este trabalho se propõe a discutir de que forma a lendária Espada de Damasco pode ser entendida como um produto único da civilização islâmica medieval. Para alcançar este propósito, duas das principais características desta arma serão discutidas, seu formato como sabre, e sua matéria prima, o aço de cadinho. Finalmente, a etapa experimental realizada nos permite avaliar sob nossa própria perspectiva as duas principais hipóteses para explicar a formação do padrão de damasco, propostas por Verhoeven e Sherby. Além disso, as tentativas de reprodução do aço de cadinho nos levam a propor a hipótese do ferro fundido, invenção sabidamente chinesa, ter sido descoberto de forma acidental ao tentar produzir aço de cadinho. / The Damascus sword was the weapon of choice of the Muslim medieval armies. It is so closely related to the Islamic civilization that it became one of its symbols. This saber was known by its great mechanical properties, as much as its pleas-ant wavy pattern. All these attributes, added to its mystical meaning, turned it into an object to be reproduced and desired by the West. Between the 9th and 13th centuries AD, the Muslim society experienced its height as civilization, compiling, translating, analyzing and developing a wide body of knowledge of many fields, imported from the main civilizations with whom it coexist-ed. On military matters, nomadic peoples from central Asia invaded the Islamic world, bringing innovations with them, such as the saber. The Muslim medieval Empire pro-vided suitable conditions to allow the Damascus sword to be created. Specially, be-cause this civilization assimilated several influences from East and West, essential to the development of this weapon: its shape as saber was taken from the nomadic Turkic peoples, the technology of the crucible steel came from the East; Central Asia and India. This thesis discusses how the legendary Damascus sword may be understood as a unique product of the medieval Islamic civilization. Two of the most important features of this weapon will be discussed in order to reach our purpose: its design as a saber, and its raw material, the crucible steel. Finally, the experimental part allow us to assay, through our own perspective, the two main hypothesis what explain the origin of the Damascus pattern, suggested by Verhoeven and Sherby. Moreover, the different attempts to reproduce the UHC crucible steel lead us to formulate a hypothesis on the origin of the cast iron, a known Chinese invention, which could have been discovered by accident while trying to produce crucible steel.

Le présent travail de thèse s'inscrit dans le cadre de la mise au point d'un nouveau procédé de fusion d'oxydes dans un four chauffé par induction. Le procédé étudié met en jeu des fortes interactions entre des phénomènes électromagnétique, thermique et hydrodynamique dans un milieu fluide aux propriétés physiques fortement dépendantes de la température. L'objectif de la thèse est de modéliser le procédé en couplant étroitement le chauffage par effet Joule, le brassage mécanique et la vidange du four. La modélisation de l'évolution temporelle de l'interface entre le verre et l'air lors de vidange du creuset froid a été réalisée. S'agissant de la méthodologie, nous avons choisi de coupler deux logiciels : Flux® pour le calcul électromagnétique et Fluent® pour la thermo-hydraulique. L'évolution de la surface libre a été traitée par la méthode multiphasique « Volume-Of-Fluid – VOF », et l'agitation mécanique par les modèles « Moving Reference Frame » et « Sliding Mesh ». Nous avons d'abord considéré la vidange sans agitation mécanique d'une cuve remplie d'une huile silicone de haute viscosité. Ce modèle initial prend en compte des études de similitude hydraulique entre l'huile silicone et le verre. Puis nous avons superposé l'écoulement forcé crée par un agitateur mécanique et les phénomènes électromagnétique et thermique afin modéliser l'écoulement du bain de verre fondu. Le modèle final permet de fournir de diverses grandeurs, notamment des estimations pour le temps de vidange, le flux thermique et l'évolution temporelle du débit massique et de la température dans le four. / This thesis is part of the development of a new technology of oxides melting in a furnace heated by induction. The technology studied involves strong interactions between electromagnetic, thermal and hydrodynamic phenomena in a flow with physical properties strongly dependents of the temperature. The aim of the thesis is the modelling of the process by coupling closely the Joule heating, the mechanical stirring and the draining of the furnace. The modeling of the time evolution of the interface between glass and air during the emptying of the cold crucible was performed. Regarding the methodology, we chose to combine two scientific codes: Flux® for the electromagnetic calculation and Fluent® for thermal-hydraulics. The evolution of the free surface was treated by the multiphasic method "Volume -Of- Fluid - VOF" and the mechanical stirring by the “Moving Reference Frame” and the “Sliding Mesh”. First of all, we considered the draining of a tank filled with a silicon oil of high-viscosity without mechanical stirring. This initial model took into account studies of hydraulic similarity between the silicon oil and the glass. Then we superimposed the forced flow creates by the mechanical stirrer, the thermal and the electromagnetic phenomena in order to model the flow of the molten glass. The final model can provide various parameters, including the time needed to drain the furnace, the heat transfer flux and the time evolution of the mass flow rate and of the temperature inside de furnace.

Made available in DSpace on 2015-05-14T12:39:29Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 792253 bytes, checksum: e7e7740d123d5bccff8f733ade9bb8e7 (MD5) Previous issue date: 2011-04-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research paper aims at investigating the relationship between history and fiction in the construction of Arthur Miller s play The Crucible, 1953. After situating the reader in the context of the modern American Theater, as in the period of the author's life, in an attempt to situate the text in the context of Miller s time, seeking an interpretation that incorporates dialectically the exteriority to the interiority of the work, we trace the real facts which happened in Salem in 1692, in a chronological and sequential order, as befits a historical investigation. Searching for a better comprehension of The Crucible, we examined the relationship between history and fiction, as understood by important philosophers and theorists throughout the centuries. Based on essential parameters to the understanding of this complex relationship and in possession of relevant concepts about the theory of drama, we analysed the play in the light of the proposed theories. The main results show that, The Crucible is a play based on the story of the tragic episode of the Salem Witch Hunts, but it is not history in the sense the word is used by an academic historian. The work concludes that Arthur Miller was careful enough to adjust the historical material he raised about Salem to his fictional purposes and, through dramatic strategies, he not only showed the historical events from a critical perspective, but he was also able to create an excess of meaning that transforms his historical play into an allegory of oppression and persecution. / A presente pesquisa tem por objetivo investigar as relações entre história e ficção na construção da peça The Crucible (As Bruxas de Salém, 1953), de Arthur Miller. Após situar o leitor no teatro moderno norte-americano e na vida do autor, buscando assim enquadrar os estudos do texto no contexto da época de Miller, visando uma interpretação que dialeticamente integre a exterioridade à interioridade da obra, rastreamos os fatos reais ocorridos em Salém em 1692, numa ordem cronológica e sequencial, como nos orienta uma investigação histórica. Numa tentativa de melhor compreender As Bruxas de Salém, examinamos com mais profundidade a relação entre história e ficção, tal como compreendida por importantes filósofos e teóricos ao longo dos séculos. Com base em parâmetros essenciais à apreensão dessa complexa relação e de posse de uma série relevante de conceitos sobre a teoria do drama, analisa-se a peça à luz das teorias propostas. Os principais resultados mostram que, As Bruxas de Salém é uma peça baseada em relatos e documentos históricos relativos ao trágico episódio da caça às bruxas de Salém, mas não é história no sentido em que a palavra é usada pelo historiador acadêmico. O trabalho conclui que Arthur Miller teve o cuidado de ajustar o material histórico por ele levantado em Salém ao seu propósito dramático e que, através de estratégias dramáticas, não apenas mostrou os eventos históricos sob uma perspectiva crítica, como também foi capaz de criar um excesso de significado que transforma sua peça histórica numa alegoria da opressão e da perseguição.

Thesis (MTech (Faculty of Engineering))--Cape Peninsula University of Technology, 2009.Included bibliographical references (p. 98-99).

La vitrification des déchets nucléaires de hautes activités est une étape importante à maîtriser afin d’assurer leur confinement. Depuis 2010, un procédé de vitrification en creuset froid présentant de nombreux avantages est exploité à cet effet dans l’usine de La Hague. Cette technologie est basée sur la circulation de courants électromagnétiques directement dans la charge du creuset dont les parois sont refroidies. Grâce au gradient thermique créé entre ces parois refroidies et le bain de verre en fusion, une couche de verre solide appelée autocreuset est formée jouant le rôle de barrière anticorrosive et électriquement isolante. Du fait de leur composition et de leur microstructure complexes, l’étude des propriétés électriques et diélectriques des verres d’intérêt nucléaire et la compréhension des phénomènes mis en jeu sont nécessaires afin de maîtriser convenablement le fonctionnement du procédé en creuset froid ainsi que les simulations thermo-hydrauliques qui lui sont associées.L’étude présentée ici porte sur la description des phénomènes de mouvements de charges électriques à l’origine des propriétés électriques et diélectriques ayant lieu au sein de verres borosilicatés d’intérêt nucléaire. Des relations entre ces propriétés et la composition ainsi que la microstructure de ces verres sont également établies. Ces problématiques sont tout d’abord abordées dans le cas de deux verres technologiques inactifs de compositions complexes grâce à des caractérisations microstructurales et des mesures d’impédance complexe à l’état solide. Une description plus détaillée des phénomènes mis en jeu est réalisée grâce à la caractérisation de verres simplifiés à 5 oxydes (SiO2-B2O3-Na2O-CaO -RuO2 ou -MoO3) permettant ainsi une meilleure compréhension des mouvements de charges selon la fréquence du champ électrique, la température ainsi que la composition et la microstructure du matériau. / The vitrification of high-level nuclear waste is an important step to master in order to ensure their immobilization. Since 2010, a cold crucible induction melter is used in the La Hague plant due to its advantages. This process is based on electromagnetic currents directly induced on the load of the crucible whose walls are water-cooled. Thanks to the thermal gradient established between these cooled walls and the molten glass, a solid glass layer called self-crucible is created which protects the crucible from corrosion effects and acts as an electrical insulator. Due to their complex composition and microstructure, the study of electrical and dielectric properties of nuclear glasses and the understanding of the related phenomena are necessary in order to efficiently master the cold crucible process and the associated thermo-hydraulic simulations.This study is dealing with the description of the electric charge motion phenomena involving the electrical and dielectric properties of the nuclear borosilicate glasses. Relationships between these properties, the composition and the microstructure are also given. These issues are firstly broached through the investigation of two industrial inactive glasses of complex composition thanks to microstructure characterizations and complex impedance measurements in the solid-state. A more detailed description of the phenomena is performed thanks to the characterization of simplified glasses containing 5 oxides (SiO2-B2O3-Na2O-CaO -RuO2 or -MoO3) allowing a better understanding of the charge motion according to the electrical field frequency, the temperature, the composition and the microstructure of the material.

La vitrification des déchets radioactifs de haute activité et vie longue permet d'assurer leur confinement à long terme grâce à l'intégration à l'échelle atomique des radioisotopes au sein d'une matrice vitreuse. Parmi les différents procédés de vitrification, celui basé sur l'utilisation d'un creuset froid à induction électromagnétique directe présente de nombreux avantages. Il est à ce titre en fonctionnement depuis 2010 à l'usine française de retraitement de la Hague. Affiner la compréhension et la modélisation des phénomènes en jeu dans un creuset froid lors de l'élaboration de verre constitue un enjeu décisif pour le soutien industriel et l'appui des démarches d'optimisation du procédé. Dans cette optique, nos travaux proposent un modèle multiphysique ainsi qu'une simulation numérique prédictive prenant en compte l'ensemble des phénomènes couplés régissant le comportement de la charge de verre lors de son élaboration en creuset froid, en termes de convection, de flux thermiques et d'interactions électromagnétiques. Dans un premier temps sont formulées les hypothèses de travail permettant la modélisation mathématique du système magnéto-thermo-hydraulique avec un degré d'approximation contrôlé. Nous mettons notamment en place une approche multi-échelle pour la prise en compte de la nature diphasique du verre nucléaire, constitué d'une matrice homogène présentant des particules métalliques micrométriques de platinoïdes en suspension. La résolution numérique du modèle couplé est alors assurée par le développement et l'utilisation de codes de simulation précis, stables et optimisés, en proposant des schémas numériques et des méthodes de couplage adaptés. Une grande part de nos travaux est dédiée à l'analyse des phénomènes physiques caractéristiques de la fusion du verre, liés de manière générale aux propriétés physico-chimiques variables du matériau (viscosité, masse volumique, conductivité électrique...). Sont notamment étudiés deux grands axes qui constituent des apports applicatifs importants : le transport, la réponse à l'induction et la sédimentation des particules de platinoïdes ainsi que les échanges thermiques entre le verre en fusion et les parois refroidies du creuset. Des lois d'échelle pour l'évaluation de l'intensité respective de ces phénomènes sont dérivées de l'analyse du modèle couplé. Enfin, des comparaisons expérimentales précises, à la fois à petite échelle et à l'échelle industrielle, permettent de valider l'approche choisie et les résultats obtenus. / The vitrification of high-level nuclear waste ensures their long-term confinement through atomic integration of radioisotopes within a vitreous matrix. Among the various vitrification processes, the one based on the use of a cold crucible with direct electromagnetic induction shows many advantages. Thus it has been in operation since 2010 at the French reprocessing plant at La Hague. Refining the understanding and the modeling of the phenomena involved during glass melting inside a cold crucible constitutes a decisive stake for industrial support and process optimization. In this context, our work presents a multiphysics model as well as a predictive numerical simulation taking into account all the coupled phenomena governing the behavior of the glass melt, in terms of convection, heat fluxes and electromagnetic interactions. The working hypotheses are first formulated, allowing the mathematical modeling of the magneto-thermo-hydraulic system with a controlled degree of approximation. In particular, we design a multi-scale approach to take into account the diphasic nature of nuclear glass, consisting of a homogeneous matrix seeded with micrometric particles mostly made of platinum-group metals. The numerical resolution of the coupled model is then assured by the development and use of precise, stable and optimized simulation codes, by proposing numerical schemes and adapted coupling methods. A large part of our work is dedicated to the analysis of the physical phenomena characteristic of glass melting, generally related to the variable physicochemical properties of the material (viscosity, density, electrical conductivity...). In particular, two main axes are studied here with important applications: transport, response to the induction and settling of the platinum-group metal particles and heat transfers between the molten glass and the cooled walls of the crucible. Scaling laws for the evaluation of the respective intensity of these phenomena are derived from the coupled model analysis. Finally, precise experimental comparisons, both on a small scale and on an industrial scale, make it possible to validate the chosen approach and the outcoming results.

The effect of solidification conditions on microstructural and mechanical properties of eutectic TiFe alloy cast under different conditions was examined. Samples exhibit different ultrafine eutectic structures (β-Ti(Fe) solid solution + TiFe). Different cooling conditions lead to the evolution of ultrafine eutectic oval-shaped colonies or elongated lamellar colonies with preferred orientation. Isotropic as well as anisotropic mechanical properties were obtained. Alloys exhibit compressive strengths between 2200 and 2700 MPa and plastic strains between 7 and 19 pct. in compression.

Es werden metallische Kurzfasern, die durch ein Schnellerstarrungsverfahren direkt aus der Schmelze hergestellt werden, bezüglich ihrer Verwendung als hochporöser Absorber und als elektrisch leitfähige Strukturen in Verbundwerkstoffen vorgestellt. Auf der Basis einer schalldämpfenden hochporösen gesinterten Metallfaserstruktur und einer schalldämmenden Elastomerplatte wird ein neuartiges Schallschutzmaterial beschrieben. Die Theorie des homogenen Mediums ist für Absorber mit schichtartigen Aufbau erweitert und mit den gemessenen Absorberkennwerten verglichen worden. Weiterhin wird gezeigt, dass schmelzextrahierte metallische Kurzfasern in Polymerwerkstoffe eingelagert werden können, um einen elektrisch leitfähigen Faserverbundwerkstoff zu erhalten, der eine höhere Leitfähigkeit als rußgefüllte Polymere aufweist und eine preiswerte Alternative zu intrinsich leitenden Polymeren darstellt. Es werden die Herstellung und mechanische Eigenschaften des Metallfaserverbundwerkstoffes beschrieben. Das elektrische Verhalten des Faserverbundwerkstoffes wird anhand der Perkolationstheorie erläutert. Ausgehend von einem umfangreichen Überblick zu Möglichkeiten der Modellierung mechanischer und elektrischer Eigenschaften wird anhand geeigneter Modelle das reale Werkstoffverhalten beschrieben.