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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
51

Chevaliers et hommes d'armes dans l'espace bourguignon au XVe siècle / Knights and men-at-arms in the Burgundian territories in the 15th century

Forster, Lois 07 December 2018 (has links)
Chacun de leur côté, les phénomènes de la guerre et des tournois au Moyen Âge ont déjà bénéficié d’études nombreuses et approfondies. En revanche, on a négligé d’analyser en profondeur le lien entre ces deux mondes, accusé pourtant de s’étioler au XVe siècle au profit de spectacles grandioses n’ayant plus rien à voir avec la réalité d’un champ de bataille. Par ailleurs, dans le domaine militaire, les gentilshommes imprégnés d’un idéal chevaleresque obsolète se débattraient pour essayer de faire encore croire au maintien de leur suprématie guerrière.La réalité est bien plus complexe et les interactions entre le domaine de la guerre et celui des lices sont multiples. Ce sont d’abord les mêmes personnes qu’on peut retrouver à combattre dans tous les contextes, des hommes censés être nobles, adoubés ou non, qui possèdent un équipement caractéristique, armes et armures, ainsi qu’un cheval entraîné au combat. Les adaptations de leur matériel aux rencontres normées, prévues pour augmenter leur sécurité, ne changent fondamentalement rien à leur façon de combattre. Leurs techniques martiales se révèlent riches et variées, tout comme leurs tactiques collectives, qui savent s’adapter aux différentes configurations rencontrées à la guerre grâce à une surprenante polyvalence. Enfin, la mentalité avec laquelle les hommes d’armes abordent les rencontres armées montrent d’importantes similitudes dans tous les contextes : on attend d’eux qu’ils donnent le meilleur d’eux-mêmes, en démontrant leur prouesse, sans renoncer face à l’adversité. Ainsi, à tous les niveaux, la frontière entre les lices et le champ de bataille s’avère finalement assez floue. / The phenomena of war and tournaments in the Middle Ages have already benefitted from several individual in-depth studies. However, a detailed analysis of the link between the two themes has always been lacking, even though we often accusingly claim that this link declined during the 15th century to be replaced by spectacular shows which had nothing to do with the reality of battlefields anymore. Moreover, some people would argue that, in the military field, noblemen – immersed in an obsolete chivalrous model – would have desperately tried to maintain a semblance of belligerent dominion.But the truth is far more complex and the interactions between the world of war and the world of lists are numerous. First, the same persons could be found in each context: men supposed to be noble – knighted or not – with characteristic pieces of equipment – arms and armours – and horses trained for combat. Adjusting their equipment for formal combats to improve their safety did not fundamentally change the way they fought. Their martial techniques were, in fact, rich and diverse – and so was their group tactic, which could adapt to different configurations encountered at war thanks to their surprising versatility. Lastly, the ways of men-at-arms in martial encounters reveals important similarities in every context: we expected them to give their best and achieve feats with no sign of renouncement while facing the enemy. Thus, the boundary between lists and battlefields actually turns out to be quite vague at every level.
52

Étude dynamique pour définition d'aciers de blindage innovants contre les explosions / Dynamic study for a definition of innovative armor steels against explosions

Mbarek, Imen Asma 07 November 2017 (has links)
Le travail de thèse de doctorat porte sur une étude complète du comportement dynamique de trois aciers de blindage soumis à des impacts balistiques. Dans un premier temps, afin de comprendre les phénomènes mis en jeu pendant la perforation de cibles fines, des essais de caractérisation du comportement thermo-viscoplastique et de rupture ont été réalisés. Les paramètres des lois de comportement et des critères de rupture ont été identifiés pour alimenter un modèle numérique simulant l'essai de perforation. La réponse des cibles impactées par des projectiles coniques a ensuite été évaluée à l'aide d'essais de perforation. Grâce à cette étude, il est possible de valider l'implémentation des lois et des critères réalisée dans des codes de calcul. Un dispositif de mesure des efforts d'impact et de perforation a donc été développé au cours de la thèse. Il fût montré que la mesure des efforts ainsi obtenue n'est pas intrinsèque au matériau impacté mais qu'elle dépend de la réponse globale du dispositif support-cible. Les résultats numériques issus de l’analyse par la méthode des éléments finis (MEF) ont été comparés aux résultats expérimentaux. Il a été observé un bon accord en terme de courbes balistiques, de modes de rupture, d’efforts dynamiques et de bilan énergétique. La modélisation numérique montre que seule une description précise du comportement mécanique des matériaux et de la rupture permet d'avoir une bonne représentation des performances balistiques des aciers étudiés. Une attention toute particulière a été portée sur l’influence de la tri-axialité des contraintes locales initiée par la forme de l’impactant, de la vitesse de déformation et de la température sur le seuil de déformation à la rupture. En perspective, les résultats issus de cette étude pourront servir dans l'analyse de la réponse des aciers de blindage sous chargements par explosif / The main aim of this PhD thesis is to develop a comprehensive study of the dynamic behavior of three armor steels subjected to ballistic impact. In order to have better understanding of the phenomena which take place during the thin targets perforation process, characterization experiments allowing to describe of the thermo-viscoplastic behavior and fracture were carried out. The identification of the constitutive relations and the failure criteria parameters allow to establish a numerical model simulating the perforation test. The ballistic response of armor steels subjected to the impact of conical projectiles was then assessed using perforation testing. This experimental investigation aims at endorsing the implementation of the behavior and fracture models in the calculation software. An experimental set-up for perforation forces measurements was specially developed during the thesis. It has been found that this dynamic force measurement is not intrinsic to the target material. It is rather dependent on the structural response of the used set-up support-target during impact and perforation. The numerical results from the Finite Elements Analysis (FEA) were compared to the experimental data and good agreement was found in terms of ballistic curves, failure patterns, impact forces and energy balance. Numerical investigations show that only an accurate description of the mechanical behavior and the fracture allows a good prediction of the ballistic performances of armor steels. Close attention was paid to the influence of local stress triaxiality induced by the projectile nose shape, strain rate and temperature on the strain to fracture threshold. In the future, these investigations can be used in the behavior analysis of armor steels subjected to blast loading
53

Analysis of Electrical and Thermal Stresses in the Stress Relief System of Inverter Fed Medium Voltage Induction Motors

Sharifi-Ghazvini, Emad 10 January 2011 (has links)
Pulse width modulation (PWM) voltage source converters (VSC) are one type of motor drives that have become popular because they enable precise control of speed and torque in medium voltage motors. However, these drives are known to have adverse effects on the insulation system particularly on conductive armour tape (CAT) and semi-conductive stress grading tape (SGT). These tapes, which are crucial components of the insulation system, control the surface electrical stresses in the stator slot and in the end portion of the form-wound coils outside the grounded stator. The material properties of CAT and SGT and the methods by which they are applied on form-wound motor coils are traditionally designed for power frequency, or a 60 Hz sinusoidal voltage. However, because of the high frequencies associated with the repetition rate and the fast rise time of the PWM pulses, elevated electrical and thermal stresses develop in these tapes, which can lead to premature insulation failure. Little research has been conducted with respect to understanding the mechanism of dielectric heating as a function of frequency and repetitive pulse characteristics. The material characterization of CAT and SGT is a vital part of an investigation of the performance of the stress relief system at high frequencies. In this study, the anisotropic dielectric properties of CAT and SGT have been measured in dc and ac and in low and high electric fields. The laboratory experiments for determining the material characteristics are discussed and the results analyzed. According to the ac space charge limited field (SCLF) theory, the maximum ac tangential component of the electric field in a nonlinear resistive SGT on medium voltage form-wound motor coils can be predicted from the field dependent electrical conductivity and the frequency. However, the SCLF theory cannot predict the total electric field (vector sum of the tangential and normal components) in the air adjacent to the surface of the tapes. Simulations of the electric field using a finite element method (FEM), is one of the best ways of finding the resultant electric field distribution in the air space adjacent to the SGT. However, prior to this study, researchers simplified the modelling of the stress relief system to avoid the convergence problems that develop due to the nonlinearity of the SGT conductivity as a function of the electric field, and also because of the geometry and dimensions of the tapes when their depths are orders of magnitude smaller than the other dimensions associated with form-wound coils. For modelling the stress grading (SG) system at power frequency and at the rated voltage, the dc isotropic conductivity of the SGT and CAT has also been extensively investigated. However, relatively little work has been done with respect to the ac electrical behaviour of these materials and dc modelling cannot reflect the effects of high-frequency stresses on the machine insulation. In this study, comprehensive transient FEM modelling has been developed in order to simulate the insulation system with nonlinear field dependent materials. The actual dimensions of the components are applied in the model, and the appropriate material parameters for the FEM simulations are extracted from the experimental test results. One crucial point that has not been considered in previous studies is the effect of the component of the electric field that is normal to the surface of the coil. In most studies, only the tangential component of the electric field is considered; however, in this study, both components and the resultant electric field are computed. The surface tangential field is calculated with reference to the gradient of the surface potential as measured with an electrostatic voltmeter. It is shown that this technique can provide a reasonable estimate for the tangential field along the SG system, but not without limitations, which are discussed in detail. Based on laboratory work and analytical analysis, this research has successfully determined the relationship between the thermal effect of the PWM voltage and the other repetitive fast pulses, such as square wave and impulse voltages. The influence of the pulse characteristics on the development of stresses has also thoroughly investigated, and the results are presented. A coupled electric and thermal model that incorporates the finite element method (FEM) is used as a means of studying thermal stresses and determining appropriate remedies. However, using transient analysis as an approach for finding the temperature profile associated with high repetitive impulses (1-10 kHz) and fast rise times (~200 ns) is both difficult and impractical. According to these considerations, an alternative method has been developed from stationary analyses based on two sinusoidal voltages of different frequencies. The frequency and amplitude of these sinusoids are measured relative to the switching frequency, signal power, and nonlinearity of the system, and the results of the simulation are then verified experimentally, thus showing the efficacy of this method. This research also concluded that a capacitive SG system with conductive foil embedded in the groundwall insulation can be a practical alternative to a conventional SGT of form-wound coils in inverter fed motors. The performance of the capacitive SG scheme is independent of frequency and can therefore provide the required mitigation of the stress caused by repetitive fast pulses. The results of the evaluation of this system with respect to qualification tests demonstrate the effectiveness of the system.
54

Behavioural ecology of foraging and predator avoidance trade-offs in Lake Sturgeon (Acipenser fulvescens)

2014 April 1900 (has links)
I investigated Lake Sturgeon (Acipenser fulvescens) foraging and anti-predator behaviour. My goals were to understand: (1) The role of environmental change on foraging and anti-predator behaviour trade-offs. (2) The relative cost/benefit trade-off between escape behaviour and cover-seeking behaviour. (3) How development of several independent morphological traits affects anti-predator behaviours. I used simulated river mesocosms to study Lake Sturgeon behavioural ecology under controlled conditions. I found: (1) Foraging intensity was significantly higher during the night than the day as well as in turbid environments versus clear environments, indicating that decreased turbidity alone, may in part drive anti-predator behaviour and constrain foraging activity. (2) In high-risk clear-water environments, Lake Sturgeon responded to danger by evoking an escape response and seeking cover in rocky microhabitats. However, in low-risk turbid environments, Lake Sturgeon responded to danger by seeking cover in rocky microhabitats, but not fleeing to a significant degree. Cover-seeking behaviour may therefore be a relatively low-cost/high-benefit anti-predator strategy. (3) Strong evidence for trait co-dependence between escape responses and body size, where larger fish were able to elicit stronger escape responses. I also found that cover-seeking behaviour exhibited a complex multi-tiered relationship, representing a mixture of trait compensation and trait co-specialization that is dependent on specific combinations of morphological traits. These findings are important because they help us understand: (1) The degree to which anti-predator behaviour can be influenced by changing environmental conditions. (2) The relative cost/benefit trade-off between two common anti-predator behaviours. (3) How behaviour and morphology interact in species with a complex anti-predator phenotype.
55

Analysis of Electrical and Thermal Stresses in the Stress Relief System of Inverter Fed Medium Voltage Induction Motors

Sharifi-Ghazvini, Emad 10 January 2011 (has links)
Pulse width modulation (PWM) voltage source converters (VSC) are one type of motor drives that have become popular because they enable precise control of speed and torque in medium voltage motors. However, these drives are known to have adverse effects on the insulation system particularly on conductive armour tape (CAT) and semi-conductive stress grading tape (SGT). These tapes, which are crucial components of the insulation system, control the surface electrical stresses in the stator slot and in the end portion of the form-wound coils outside the grounded stator. The material properties of CAT and SGT and the methods by which they are applied on form-wound motor coils are traditionally designed for power frequency, or a 60 Hz sinusoidal voltage. However, because of the high frequencies associated with the repetition rate and the fast rise time of the PWM pulses, elevated electrical and thermal stresses develop in these tapes, which can lead to premature insulation failure. Little research has been conducted with respect to understanding the mechanism of dielectric heating as a function of frequency and repetitive pulse characteristics. The material characterization of CAT and SGT is a vital part of an investigation of the performance of the stress relief system at high frequencies. In this study, the anisotropic dielectric properties of CAT and SGT have been measured in dc and ac and in low and high electric fields. The laboratory experiments for determining the material characteristics are discussed and the results analyzed. According to the ac space charge limited field (SCLF) theory, the maximum ac tangential component of the electric field in a nonlinear resistive SGT on medium voltage form-wound motor coils can be predicted from the field dependent electrical conductivity and the frequency. However, the SCLF theory cannot predict the total electric field (vector sum of the tangential and normal components) in the air adjacent to the surface of the tapes. Simulations of the electric field using a finite element method (FEM), is one of the best ways of finding the resultant electric field distribution in the air space adjacent to the SGT. However, prior to this study, researchers simplified the modelling of the stress relief system to avoid the convergence problems that develop due to the nonlinearity of the SGT conductivity as a function of the electric field, and also because of the geometry and dimensions of the tapes when their depths are orders of magnitude smaller than the other dimensions associated with form-wound coils. For modelling the stress grading (SG) system at power frequency and at the rated voltage, the dc isotropic conductivity of the SGT and CAT has also been extensively investigated. However, relatively little work has been done with respect to the ac electrical behaviour of these materials and dc modelling cannot reflect the effects of high-frequency stresses on the machine insulation. In this study, comprehensive transient FEM modelling has been developed in order to simulate the insulation system with nonlinear field dependent materials. The actual dimensions of the components are applied in the model, and the appropriate material parameters for the FEM simulations are extracted from the experimental test results. One crucial point that has not been considered in previous studies is the effect of the component of the electric field that is normal to the surface of the coil. In most studies, only the tangential component of the electric field is considered; however, in this study, both components and the resultant electric field are computed. The surface tangential field is calculated with reference to the gradient of the surface potential as measured with an electrostatic voltmeter. It is shown that this technique can provide a reasonable estimate for the tangential field along the SG system, but not without limitations, which are discussed in detail. Based on laboratory work and analytical analysis, this research has successfully determined the relationship between the thermal effect of the PWM voltage and the other repetitive fast pulses, such as square wave and impulse voltages. The influence of the pulse characteristics on the development of stresses has also thoroughly investigated, and the results are presented. A coupled electric and thermal model that incorporates the finite element method (FEM) is used as a means of studying thermal stresses and determining appropriate remedies. However, using transient analysis as an approach for finding the temperature profile associated with high repetitive impulses (1-10 kHz) and fast rise times (~200 ns) is both difficult and impractical. According to these considerations, an alternative method has been developed from stationary analyses based on two sinusoidal voltages of different frequencies. The frequency and amplitude of these sinusoids are measured relative to the switching frequency, signal power, and nonlinearity of the system, and the results of the simulation are then verified experimentally, thus showing the efficacy of this method. This research also concluded that a capacitive SG system with conductive foil embedded in the groundwall insulation can be a practical alternative to a conventional SGT of form-wound coils in inverter fed motors. The performance of the capacitive SG scheme is independent of frequency and can therefore provide the required mitigation of the stress caused by repetitive fast pulses. The results of the evaluation of this system with respect to qualification tests demonstrate the effectiveness of the system.
56

Military fortifications, weaponry, warfare and military strategy in ancient Syro-Palestine (Iron Age II A)

Human, Gary Leroy 30 June 2006 (has links)
he title above comprises elements of the strategic studies concept 'foundations of military force'. Military force has been the final arbiter between the political entities of mankind throughout all ages. The prevalence of this social scourge has left a footprint in every dispensation of man's efforts at civilisation. Regrettably, warfare was and remains one of the core characteristics of human nature. The artefacts of antiquity are catalogued in archaeological periods. In nearly every instance each layer of human settlement is separated by the effects of warfare. Rather than a sub-discipline on the periphery it is demonstrated herein that military archaeology, refined with the post-World War Two scientific discipline of polemology, can and ought to be moved onto the centre stage of archaeology. The application of core polemological concepts to IA IIa accurately describes the unfolding of the United Monarchy's capacity to pursue political goals commensurate with its evolutionary war potential. / Religious Studies & Arabic / M.A. (Biblical Studies)
57

La Furūsiyya des Mamlûks : Une élite sociale à cheval (1250-1517)

Carayon, Agnès 26 June 2012 (has links)
Les Mamlûks sont réputés pour avoir porté les arts de la furūsiyya à leur plus haute expression. Cette thèse a pour objectif de cerner à la fois les enjeux de leur dextérité, et ses caractéristiques. La première partie porte sur la littérature de la furūsiyya. Après un bilan historiographique, plusieurs ouvrages de furūsiyya sont analysés et comparés, afin de mieux appréhender les héritages et les apports proprement mamlûks. Un traité anonyme de maniement de dabbūs et de lutte à cheval, contenant également une partie sur les feux de guerre, est édité et traduit. La deuxième partie de cette thèse porte sur la suprématie militaire des Mamlûks. Leur formation très poussée y est décrite, mais la lumière a aussi été mise sur leurs chevaux : leurs races ; leur dressage ; leur nombre ; leur entretien. Un large échantillon d'armes mamlûkes est présenté. Enfin, un chapitre est consacré au problème des procédés de combat, encore très mal connus, qui tend à nuancer la vision d'archers montés que l'on a généralement des Mamlûks. Enfin, la dernière partie relève de l'histoire sociale. Elle a pour ambition de démontrer que la maîtrise de la furūsiyya était perçue par les Mamlûks comme la détention d'un art complexe, un « attribut de distinction » qui les distinguait du vulgum pecus. Ce sont alors les diverses manifestations de cette appartenance sociale qui sont analysées : les « sports » équestres, les lieux de jeu et d'entraînement militaire et les palais-écuries, enfin les institutions et les spectacles.Les annexes contiennent un tableau détaillé des manuscrits de furūsiyya et un glossaire, en plus de quelques planches. / The Mamluks are renowned for bringing the arts of furūsiyya to their highest expression. This thesis aims to identify both the issues of their dexterity, and characteristics.The first part focuses on the literature of furūsiyya. After a historiographical balance, several treatises of furūsiyya are analyzed and compared in order to better understand the legacy and contributions properly Mamluk. An anonymous treatise of handling dabbūs and fight on horseback, also containing some of the fires of war, is edited and translated.The second part of this thesis is on their military supremacy.Their extensive training is described, but the light was also put on their horses : races, training, numbers and maintenance. A wide selection of Mamluk weapons is presented. Finally, a chapter is devoted to the problem of combat methods, very little known, which tends to moderate vision of mounted archers that is generally widespread.The last part focus on social history. It aims to demonstrate that furūsiyya mastery was seen by the Mamluks as the knowledge of a complex art, an "attribute of distinction", which distinguished them from the hoi polloi. Then, the various manifestations of belonging to this social class are analyzed: "sports" riding, gambling venues and military training, and palace-stables, and finally the institutions and the shows.The appendices contain a detailed table of manuscripts of furūsiyya, a glossary and a few plates.
58

Military fortifications, weaponry, warfare and military strategy in ancient Syro-Palestine (Iron Age II A)

Human, Gary Leroy 30 June 2006 (has links)
he title above comprises elements of the strategic studies concept 'foundations of military force'. Military force has been the final arbiter between the political entities of mankind throughout all ages. The prevalence of this social scourge has left a footprint in every dispensation of man's efforts at civilisation. Regrettably, warfare was and remains one of the core characteristics of human nature. The artefacts of antiquity are catalogued in archaeological periods. In nearly every instance each layer of human settlement is separated by the effects of warfare. Rather than a sub-discipline on the periphery it is demonstrated herein that military archaeology, refined with the post-World War Two scientific discipline of polemology, can and ought to be moved onto the centre stage of archaeology. The application of core polemological concepts to IA IIa accurately describes the unfolding of the United Monarchy's capacity to pursue political goals commensurate with its evolutionary war potential. / Religious Studies and Arabic / M.A. (Biblical Studies)
59

Římské vojsko ve filmu a televizi / Roman army on the screen

Balling, Adam January 2020 (has links)
1 ABSTRACT The thesis is divided into three major parts, the first giving an overview of the history of films and TV series about ancient Rome. This overview is based on scientific literature written in English. The second part, using scientific literature and classical sources, mostly pictorial, briefly describes weapons and armour of Roman soldiers from the Roman Republic until the end of the 2nd century A.D. The third part describes the costumes and weapon props in 25 films and TV shows picked on the basis of their popularity on Internet movie databases. The aim of this thesis is to find out, how does the stereotypical Roman soldier, created by this branch of popculture, looks like. The conclusion shows, that in the films and series about ancient Rome, the costumes rarely correspond to our historical knowledge about the armours from the times in which these films and series are set. Some costume attributes are constant and are supposed to serve as indicators, that the actor in the view of the camera is a Roman soldier. One of these attributes is lorica segmentata, armour made famous by its appearances in films like Ben-Hur, Gladiator and films about Asterix. Other attributes are attic style helmet, known from antique reliefs, big rectangular shields and bracers. Those pieces of equipment were not the...
60

Příprava a organizace výstavby výrobního areálu / Preparation and organization of the production area's construction facility

Řeháček, Martin January 2013 (has links)
This master’s thesis relate to the preparation and organization of the production area’s construction of the SPEDUR company in Žďár nad Sázavou. The thesis contents technical report on the construction technological project, construction site, time plans, project of the equipment site, draft of the mechanisms, control and testing plan, environmental plan, risks of safety and health at work and calculation for this construction.

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