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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.
61

She-Ra and the Princesses of Power : Exploring Character Development and Queer Representation

Conrad, Emelie, Malmsten, Fanny January 2022 (has links)
In this thesis the animated tv series She-Ra and the Princesses of Power and the representation and the character development within it is researched and analyzed.  In television and media, representation has a history of being narrow. But in 2018 the animated tv series She-Ra and the Princesses of Power came and showed how broad representation could be done, and how it can be done by creating characters who are allowed to develop. Our aim with the study was to study the character development and the representation, with a focus on queer identities and themes.  With the series She-Ra and the Princesses of Power as a case, and through visual analysis and character analysis we approached our study and this subject. Our study resulted with the conclusion that queer representation does not have to be direct or in your face. With focus on the characters own developments, and letting them exist in a non-heteronormative world, they got to emerge as their own persons with complex identities which are not relying on their sexual orientation or gender identity. The show instead shows that it's possible to provide broad representation where everyone can exist in a world that does not abide by the norms that are found in real society. It also became clear that the series real aim was on the importance of friendship, love and acceptance, rather than the storyline which was a mere entertaining excuse for this deeper meaning.
62

Etude mathématique et numérique de modèles de transport : application à la spintronique

El Hajj, Raymond 03 September 2008 (has links) (PDF)
Ce travail de thèse comporte trois parties. La partie principale s'intéresse au transport des courants polarisés en spin dans des matériaux à base de semi-conducteurs. Nous dérivons et analysons une hiérarchie des modèles allant du niveau microscopique au niveau macroscopique et tenant compte des différents mécanismes de rotation et de relaxation du vecteur spin dans les semi-conducteurs. Les mécanismes essentiels pris en compte sont les couplages spin-orbite et les interactions avec renversement de spin (spin-flip interactions). Une analyse semi-classique (via la transformation de Wigner) de l'équation de Schrödinger avec hamiltonien spin-orbite est présentée. Au niveau cinétique, l'équation de Vlasov (ou Boltzmann) spinorielle est une équation à valeur dans l'ensemble des matrices carrées d'ordre deux hermitiennes et positives. Partant ensuite de la spinor forme de l'équation de Boltzmann (avec différents opérateurs de collisions avec et sans renversement du vecteur spin) et par des techniques d'asymptotiques de diffusion, nous dérivons et analysons plusieurs modèles macroscopiques. Ils sont de type dérive-diffusion, SHE, Energie-Transport, à deux composantes ou spinoriels conservant des effets de rotation et de relaxation du vecteur spin. Nous validons ensuite ces modèles par des cas tests numériques. Deux applications numériques sont présentées : la simulation d'un transistor à effet de rotation de spin et l'étude de l'effet d'accumulation de spin à l'interface entre deux couches semi-conductrices différemment dopées. Dans la seconde partie, nous considérons une équation cinétique de type Boltzmann linéaire dans des domaines où un champ magnétique fort est appliqué. Nous étudions la limite de diffusion en supposant que le champ magnétique est unidirectionnel et tend vers l'infini. Le modèle obtenu est un modèle macroscopique constitué d'une équation diffusive dans la direction parallèle au champ magnétique et d'une dérive représentant l'effet centre-guide en présence d'un champ électrique dans la direction perpendiculaire. Le terme de diffusion contient des moyennes de giration de l'opérateur de collisions utilisé. Nous prouvons la convergence en utilisant des techniques d'entropie pour traiter le comportement diffusif, et en conjuguant par les rotations locales induites par le champ magnétique pour tenir compte des oscillations. Dans la troisième partie de cette thèse, Nous nous intéressons à la description du potentiel de confinement dans des gas d'électrons bidimensionnels. Nous étudions la limite faible longueur de Debye (ou faible température) du système de Schrödinger-Poisson unidimensionnel stationnaire sur un intervalle borné. Les électrons sont supposés dans un mélange d'états avec une statistique de Boltzmann (ou de Fermi-Dirac). En utilisant différentes reformulations du système comme des problèmes de minimisation convexe, nous montrons qu'asymptotiquement seul le premier niveau d'énergie est occupé. Le potentiel électrostatique converge vers une couche limite avec un profil calculé à l'aide d'un système de Schrödinger-Poisson sur le demi axe réel.
63

Aggressive Flesh: The Obese Female Other

Broom, Hannah January 2005 (has links)
My visual art practice explores the point at which a sense of bodily humour and revulsion may intersect in the world of the monstrous-feminine: the female grotesque, presented as my own obese (and post-obese) body. This exegesis is a written elucidation of my visual art practice as research. As an artist I create performative photographic images featuring taboo or otherwise 'inappropriate' subject matter, situations, materials and behaviours including bodily fluids, offal, internal organs and my own post-obese body. Through these modes of working, I establish and investigate the subjectivity of flesh: Why are we repulsed by the female grotesque? How can this flesh be used to subvert readings of the female body? My research is informed by those understandings of the female body, sexuality and difference described in the work of feminist theorists including Julia Kristeva, Helene Cixous, Ruth Salvaggio and Elizabeth Grosz. I explore the work of influential artists such as Eleanor Antin, Carolee Schneeman, Cindy Sherman and Sarah Lucas. In this context, I present my own visual art practice as a point from which the monstrous-feminine can be given voice as sentient, intelligent flesh.
64

Multilevel Dodecagonal and Octadecagonal Voltage Space Vector Structures with a Single DC Supply Using Basic Inverter Cells

Boby, Mathews January 2017 (has links) (PDF)
Multilevel converters have become the direct accepted solution for high power converter applications. They are used in wide variety of power electronic applications like power transmission and distribution, electric motor drives, battery management and renewable energy management to name a few. For medium and high voltage motor drives, especially induction motor drives, the use of multilevel voltage source inverters have become indispensible. A high voltage multilevel inverter could be realized using low voltage switching devices which are easily available and are of low cost. A multilevel inverter generates voltage waveforms of very low harmonic distortion by switching between voltage levels of reasonably small amplitude differences. Thus the dv/dt of the output voltage waveform is small and hence the electromagnetic interference generated is less. Because of better quality output generation, the switching frequency of the multilevel inverters could be reduced to control the losses. Thus, a multilevel converter stands definitely a class apart in terms of performance from a conventional two-level inverter. Many multilevel inverter topologies for induction motor drives are available in the literature. The basic multilevel topologies are the neutral point clamped (NPC) inverter, flying capacitor (FC) inverter and the cascaded H-bridge (CHB) inverter. Various other hybrid multilevel topologies have been proposed by using the basic multilevel inverter topologies. It is also possible to obtain multilevel output by using conventional two-level inverters feeding an open-end winding induction motor from both sides. All the conventional multilevel voltage source inverters generate hexagonal (6 sided polygons) voltage space vector structures. When an inverter with hexagonal space vector structure is operated in the over modulation range, significant low order harmonics are generated in the phase voltage output. Over modulation operation is required for the full utilization of the available DC-link voltage and hence maximum power generation. Among the harmonics generated, the fifth and seventh harmonics are of significant magnitudes. These harmonics generate torque ripple in the motor output and are undesirable in high performance motor drive applications. The presence of these harmonics further creates problems in the closed loop current control of a motor, affecting the dynamic performance. Again, the harmonic currents generate losses in the stator windings. Therefore, in short, the presence of harmonic voltages in the inverter output is undesirable. Many methods have been proposed to eliminate or mitigate the effect of the harmonics. One solution is to operate the inverter at high switching frequency and thereby push the harmonics generated to high frequencies. The stator leakage inductance offers high impedance to the high frequency harmonics and thus the harmonic currents generated are negligible. But, high switching frequency brings switching losses and high electromagnetic interference generation in the drive system. And also, high switching frequency operation is effective only in the linear modulation range. Another solution is to use passive harmonic filters at the inverter output. For low order harmonics, the filter components would be bulky and costly. The loss created by the filters degrades the efficiency of the drive system as well. The presence of a filter also affects the dynamic performance of the drive system during closed loop operation. Special pulse width modulation (PWM) techniques like selective harmonic elimination (SHE) PWM can prevent the generation of a particular harmonic from the phase voltage output. The disadvantages of such schemes are limited modulation index, poor dynamic performance and extensive offline computations. An elegant harmonic elimination method is to generate a voltage space vector structure having more number of sides like a dodecagon (12 sided polygons) or an octadecagon (18 sided polygons) rather than a hexagon. Inverter topologies generating dodecagonal voltage space vector structure eliminate fifth and seventh order harmonics, represented as 6n 1; n = odd harmonics, from the phase voltages and hence from the motor phase currents, throughout the entire modulation range. The first harmonics appearing the phase voltage are the 11th and 13th harmonics. Another advantage is the increased linear modulation range of operation for a given DC-link voltage, because geometrically dodecagon is closer to circle than a hexagon. An octadecagonal structure eliminates the 11th and 13th harmonics as well from the phase voltage output. The harmonics present in the phase voltage are of the order 18n 1; n = 1; 2; 3; :::. Thus the total harmonics distortion (THD) of the phase voltage is further improved. The linear modulation range also gets enhanced compared to hexagonal and dodecagonal structures. Multilevel dodecagonal and octadecagonal space vector structures combines the advantages of both multilevel structure and dodecagonal and octadecagonal structure and hence are very attractive solutions for high performance induction motor drive schemes. Chapter 1 of this thesis introduces the multilevel in-verter topologies generating hexagonal, dodecagonal and octadecagonal voltage space vector structures. Inverter topologies generating multilevel dodecagonal and octadecago-nal voltage space vector structures have been proposed before but using multiple DC sources delivering active power. The presence of more than one DC source in the inverter topology makes the back to back operation (four-quadrant operation) of the drive system difficult. And also the drive system becomes more costly and bulky. This thesis proposes induction motor drive schemes generating multilevel dodecagonal and octadecagonal volt-age space vector structures using a single DC source. In Chapter 2, an induction motor drive scheme generating a six-concentric multilevel dodecagonal voltage space vector structure using a single DC source is proposed for an open-end winding induction motor. In the topology, two three-level inverters drive an open-end winding IM, one inverter from each side. DC-link of primary inverter is from a DC source (Vdc) which delivers the entire active power, whereas the secondary inverter DC-link is maintained by a capacitor at a voltage of 0:289Vdc, which is self-balanced during the inverter operation. The PWM scheme implemented ensures low switching frequency for primary inverter. Secondary inverter operates at a small DC-link voltage. Hence, switching losses are small for both primary and secondary inverters. An open-loop V/f scheme was used to test the topology and modulation scheme. In the work proposed in Chapter 3, the topology and modulation scheme used in the first work is modified for a star connected induction motor. Again, the scheme uses only a single DC source and generates a six-concentric multilevel space vector struc-ture. The power circuit topology is realized using a three-level flying capacitor (FC) inverter cascaded with an H-bridge (CHB). The capacitors in the CHB inverter are maintained at a voltage level of 0:1445Vdc. The FC inverter switches between volt-age levels of [Vdc; 0:5Vdc; 0] and the CHB inverter switches between voltage levels of [+01445Vdc; 0; 0:1445Vdc]. The PWM scheme generates a quasi-square waveform output from the FC inverter. This results in very few switchings of the FC inverter in a funda-mental cycle and hence the switching losses are controlled. The CHB inverter switches Ch. 0: at high frequency compared to the FC inverter and cancels the low order harmonics (6n 1; n = odd) generated by the FC inverter. Even though the CHB operates at higher switching frequency, the switchings are at low voltage thereby controlling the losses. The linear modulation range of operation is extended to 48:8Hz for a base frequency of 50Hz. An open-loop V/f scheme was used to test the topology and modulation scheme. In Chapter 4, a nine-concentric multilevel octadecagonal space vector structure is proposed for the first time, again using a single DC source. The circuit topology remains same as the work in Chapter 3, except that the CHB capacitor voltage is maintained at 0:1895Vdc. The 5th; 7th; 11th and 13th harmonics are eliminated from the phase voltage output. The linear modulation range is enhanced to 49:5Hz for a base speed of 50Hz. An open-loop V/f scheme and rotor field oriented control scheme were used to test the proposed drive system. All the proposed drive schemes have been extensively simulated and tested in hard-ware. Simulation was performed in MATLAB-SIMULINK environment. For implement-ing the inverter topology, SKM75GB12T4 IGBT modules were used. The control al-gorithms were implemented using a DSP (TI’s TMS320F28334) and an FPGA (Xilinx Spartan XC3S200). A 1kW , 415V , 4-pole induction motor was used for the experiment purpose. The above mentioned induction motor drive schemes generate phase voltage outputs in which the low order harmonics are absent. The linear modulation range is extended near to the base frequency of operation compared to hexagonal space vector structure. In the inverter topologies, the secondary inverters or the CHB inverters functions as harmonic filters and delivers zero active power. The primary inverter in the topologies switches at low frequency, reducing the power loss. Single DC source requirement brings down the cost of the system as well as permitting easy four-quadrant operation. This is also advantageous in battery operated systems like EV applications. With these features and advantages, the proposed drive schemes are suitable for high performance, medium voltage induction motor drive applications.
65

主權與治權: 新疆生產建設兵團研究. / Sovereignty and the power of governance: a case study of Xinjiang Production and Construction Corps / 新疆生產建設兵團研究 / CUHK electronic theses & dissertations collection / Zhu quan yu zhi quan: Xinjiang sheng chan jian she bing tuan yan jiu. / Xinjiang sheng chan jian she bing tuan yan jiu

January 2011 (has links)
魏英杰. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 189-196) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in Chinese and English. / Wei Yingjie.
66

Courants de spin et l'effet Hall de spin dans des nanostructures latérales / Spin currents and spin Hall effect in lateral nano-structures

Laczkowski, Piotr 05 October 2012 (has links)
Cette thèse porte sur l’étude des courants de spin et de l’effet Hall de spin dans des nanostructureslatérales. Des vannes de spin latérales Py/Al, Py/Cu et Py/Au, ont été fabriquées parlithographie électronique, puis optimisées et caractérisées par des mesures de magnéto-transport.Des mesures non locales, de GMR, et d’effet Hanle ont ainsi été enregistrées à 300K et 77K. De l’optimisation des vannes de spin latérales a découlé l’observation de fortes amplitudes designal de spin. De plus, les effets du confinement latéral et vertical de l‘accumulation de spin,par utilisation d’un canal non-magnétique confiné ou de barrières tunnel AlOx, ont été mis enévidence expérimentalement et décrits théoriquement. Des simulations par éléments finis et desanalyses basées sur les modèles de diffusion 1D ont été développées, permettant l’extraction de lapolarisation effective Peff et de la longueur de diffusion de spin lNsf des données expérimentales.Enfin, l’effet Hall de spin dans des matériaux à fort angles de Hall (Pt, aliage d’Au) a étéétudié dans des hétérostructures latérales et par pompage de spin à la résonance ferromagnétique. / This PhD thesis focus on the study of spin currents and of the spin Hall effect in lateralnano-structures. Lateral spin-valves based on Py/Al, Py/Cu and Py/Au, fabricated by meansof electron-beam lithography, have been optimized and characterized using magneto-resistancemeasurements. Non-local, GMR and Hanle effect measurements have been recorded at 300K and77K. The optimization of these lateral spin-valves allowed the observation of high spin signalamplitudes. Lateral and vertical confinement effects on the spin accumulation, by using confinednon-magnetic channel and AlOx tunnel barriers, were evidenced experimentally and describedtheoretically. Finite Elements Method simulations and analyses based on a 1D diffusion modelhave been developed, allowing the extraction from our experimental data of the effective spinpolarization Peff and of the spin diffusion length lNsf .Finally, the spin Hall effect of materials with high spin Hall angles (Pt, Au alloys) has beenstudied using both hybrid lateral nano-structures and spin pumping ferro-magnetic resonance.
67

Testing and Refining a Unique Approach for Setting Environmental Flow and Water Level Targets for a Southern Ontario Subwatershed

Beaton, Andrew 15 August 2012 (has links)
In this study Bradford’s (2008) approach for setting ecological flow and water level targets is tested and refined through application within the Lake Simcoe Region Conservation Authority’s (LSRCA) subwatershed of Lover’s Creek. A method for defining subwatershed objectives and identifying habitat specialists through expert input is proposed and tested. The natural regime of each streamflow and wetland site is characterized along with the hydrological alteration at each site. Potential ecological responses to the hydrologic alterations are then hypothesized for the different types of changes calculated at each site. Methods for setting overall ecosystem health and specific ecological objective flow targets are proposed and tested. These targets are integrated into a flow regime for each site and a process for using this information for decision making is suggested. Flow magnitude quantification is attempted using hydraulic modelling and sediment transport equations, however the data used were found to be inadequate for this application. The accuracy of the targets developed using the method presented in this paper is mainly limited by the accuracy of the hydrological model and quantified flow magnitudes. Recommendations for improving these components of the assessment are made. The unique approach and recommendations presented in this paper provide explicit steps for developing flow targets for subwatersheds within the LSRCA. This research contributes toward the advancement of EFA within the LSRCA, which provides opportunity for enhanced protection and restoration of ecosystem health across the watershed. / Lake Simcoe Region Conservation Authority
68

All the Pieces Matter: Fragmentation-as-Agency in the Novels of Edwidge Danticat, Michelle Cliff, and Shani Mootoo

Morguson, Alisun 30 January 2013 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The fragmented bodies and lives of postcolonial Caribbean women examined in Caribbean literature beget struggle and psychological ruin. The characters portrayed in novels by postcolonial Caribbean writers Edwidge Danticat, Michelle Cliff, and Shani Mootoo are marginalized as “Other” by a Western patriarchal discourse that works to silence them because of their gender, color, class, and sexuality. Marginalization participates in the act of fragmentation of these characters because it challenges their sense of identity. Fragmentation means fractured; in terms of these fictive characters, fragmentation results from multiple traumas, each trauma causing another break in their wholeness. Postcolonial scholars have identified the causes and effects of fragmentation on the postcolonial subject, and they argue one’s need to heal because of it. Danticat, Cliff, and Mootoo prove that wholeness is not possible for the postcolonial Caribbean woman, so rather than ruminate on that truth, they examine the journey of the postcolonial Caribbean woman as a way of making meaning of the pieces of her life. This project contends that fragmentation – and the fracture it produces – does not bind these women to negative existences; in fact, the female subjects of Danticat, Cliff, and Mootoo locate power in their fragmentation. The texts studied include Danticat’s "Breath, Eyes, Memory" (1994) and "The Farming of Bones" (1999), Cliff’s "Abeng" (1984) and "No Telephone to Heaven" (1987), and Mootoo’s "Cereus Blooms at Night" (1996) and "He Drown She in the Sea" (2005).

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