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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.
111

Conception de systèmes antennaires omnidirectionnels et directifs favorisant les ondes de surface comme vecteur de propagation dans la bande HF / Antenna design improving the surface waves propagation in the HF band

Bellec, Mathilde 09 October 2015 (has links)
Les ondes de surface se propagent le long de la surface terrestre par-delà l'horizon et ces propriétés de propagation sont des atouts pour diverses applications industrielles (civiles ou militaires) opérant dans la bande HF. C'est le cas notamment des radars transhorizon, des systèmes de communications, de la détection de tsunami, ou encore l'étude de la courantologie. Actuellement, les aériens utilisés dans ce contexte ne sont pas optimisés pour privilégier la propagation par ondes de surface. C'est dans ce contexte que TDF, la Direction Générale de l'Armement (DGA) et l'Institut d'Electronique et de Télécommunications de Rennes (IETR) se sont associés pour proposer cette thèse. L'objectif principal de la thèse est de concevoir des antennes en bande HF de dimensions réduites (<3 mètres) réduisant le rayonnement vers le ciel afin favoriser l'onde de surface. Une première approche a permis de concevoir deux antennes élémentaires, l'une omnidirectionnelle et l'autre directive, permettant de réduire le rayonnement vers le ciel pour les sites compris entre -45° et +45°. Les solutions proposées sont de tailles très réduites grâce à l'utilisation d'une antenne à polarisation verticale électriquement courte dans le plan vertical et de parasites horizontaux alimentés par couplage EM. Les études expérimentales réalisées à échelle réelle sont en bon accord avec les performances théoriques obtenus à l'aide de logiciels d'analyse électromagnétique commerciaux. Une seconde approche a permis de concevoir des réseaux d'antennes électriquement courtes dans le plan vertical selon une disposition linéaire des aériens. La réduction du rayonnement vers le ciel est réalisée grâce aux réseaux de type Endfire/Broadside. Enfin, une troisième étude a permis de concevoir deux systèmes antennaires agiles en diagrammes tout en conservant les propriétés de réduction de rayonnement vers le ciel. Le premier système à l'aide d'antennes électriquement courtes dans le plan vertical chargées par des réactances, et le second en appliquant une pondération en amplitude et en phase d'un réseau à deux dimensions. / The surface-waves propagate beyond the horizon. This phenomenon is an attractive feature for many applications operating in the HF band both in civil or military field. By example, we can quote the High Frequency Surface Waves Radar (HFSWR), communicating systems, or the study of the currentology. Currently, the antennas used in the field of surface-waves propagation are not fully optimized and radiate also in sky wave. In order to optimize the radiation pattern of the antennas used in these systems, the company TDF, the Direction Générale de l’Armement (DGA) and the Institute of Electronic and Telecommunications of Rennes (IETR) have proposed this projetct. The main objective of this work is to design electrically small antennas in the vertical plane (< 3 meters) in the HF band while reducing the radiation toward the sky. The first concept is based on vertically polarized antennas electrically small in the vertical plane coupled to horizontally radiators placed above the antenna. As a result, the radiation pattern in the horizontal plane is omnidirectional or directive with a radiation toward the sky reduced for the elevations range from -45° to +45°. Prototypes have been realized and validated by measurements. Then, in the second study we have developed antennas array in order to reduce the radiation toward the sky with another way that the horizontal radiators. This method allows reducing significantly the radiation toward the sky according to the number of elements in the array. Finally, in the third study we have studied electronically scanning antennas while maintaining the reduction of the radiation toward the sky. The first system is based on an array of radiator loaded by reactance, and the second is based on a planar array with an appropriate feeding.
112

Development of Field Scenario Ray Tracing Software for the Analysis of Bifacial Photovoltaic Solar Panel Performance

Li, Chu Tu January 2016 (has links)
This thesis is based on a project "Bifacial Photovoltaic Energy Production Analysis" to build a detailed simulation model system accurately simulate bifacial panel performance under real field radiation conditions and deployment configuration, and to predict its corresponding energy yield. To the author’s up-to-date knowledge, the model system is unpreceded among same type simulation software in complexity, details in consideration, ranges of deployment and parameters. The model system can also be used as a platform for more components and variables to be added on, such as adding on more rows of panel arrays to simulate bifacial solar farm scenario; and adding spectral information for more accurate analysis. The system components’ sub-models were carefully chosen based on a broad literature review in related aspects; especially in sky diffuse radiance, ground reflection, and bifacial solar cells. Built in MATLAB© based on mathematical expressions from above said models, the system consists of 5 bifacial panels and their racking as shading objects and the central panel performance is under investigation and has taken consideration of all possible panel azimuth and elevation combinations. Model simplification and resolution are carefully considered so to achieve a good balance in complexity, computation load and output accuracy. Output reliability is confirmed with other people’s work. Furthermore, the model has been fully checked and peer tested. Outputs under different parameter settings are analysed and discussed. Conclusions and recommended future work are provided at the end of the thesis.
113

The decline of the Chinese matriarch : the struggle to reconcile "old" with "new"

Lee, Tara 05 1900 (has links)
The thesis examines representations of the matriarch in three Chinese Canadian texts: SKY Lee's Disappearing Moon Cafe, Wayson Choy's The Jade Peony, and Denise Chong's The Concubine's Children. The matriarch is the female head of the Chinese household who is able to gain substantial power by manipulating the assets granted to her in a patriarchal system. Dislocated from her home in China, she serves in these texts as the focal point for the collision between the New World, Canada, and the Old World, China. Confronted by a new environment, the matriarch must decide whether she will choose conformity or identity experimentation. The thesis is concerned with the way Chinese Canadian writers negotiate multiple identities through narrators who must come to terms with the divided loyalties of the women of the past. The analysis of the matriarch's identity shifts is informed by the work of the feminist theorists, Elspeth Probyn and Moira Gatens, who explore the productive potentials of rebelling against binary codes. The thesis is divided into three chapters that discuss how the texts come close to embracing identity fluidity, but cannot overcome the need to reach a coherent representation of the matriarch. The first chapter is devoted to Disappearing Moon Cafe, and argues that Lee's narrator sacrifices her female characters, albeit reluctantly, in order to privilege feminism over her Chinese heritage. The second chapter turns to The Jade Peony and discusses how Choy's child narrators give in to binary thinking by relegating Poh-Poh, the Old One, to the realm of memories to make room for the New Ways. The final chapter on The Concubine's Children explores Chong's desire to redeem a grandmother who wreaked havoc on the family when she defied traditional gender roles. The thesis concludes by determining that Lee, Choy, and Chong are reaching for a multi-voiced reading of the past, but cannot yet articulate a way out. The uncertainty of their representations of the matriarch signals their efforts to move beyond binaries to a state of coexisting identity categories. / Arts, Faculty of / English, Department of / Graduate
114

Měření rychlosti a polohy objektů optickými a elektromagnetickými metodami / Speed and position measurement using optical and electromagnetic methods

Dvořák, Zdeněk January 2010 (has links)
The project compares and describes the characteristics of optical and electromagnetic methods, used for measuring the object’s velocity. Some of these are used at the ballistic laboratory of PROTOTYPA, a.s. company. The rest is mentioned in order to increase the range of the project and are not engaged by the company. The practical part involves measuring and processing the magnetic fields of various appliances. There is a method and appliance designed to process the link between flying object and sensor.
115

Termální lázně Yverdon, pět smyslů v architektuře / Thermal baths Yverdon, five senses in architecture

Křížová, Iveta January 2015 (has links)
The aim of this work is the solution spa area includes Yverdon les Bains. The existing facility does not meet both their needs, but mainly it is very closed. Park is closed to the public and within his right in the spa area there are several other barriers. Spa Park means to me park, promenade, people moving and elegance. At this point I feel the potential that could reopen the spa park outside world and effortlessly be connected to the outside world, with reference to its historical and thermal value. Therefore, I leave the pit area as much free, with public functions. The spa itself would not be contrary overload the body, but rather a place to stop and peaceful rest. That is why I put myself into a compact mass flowing above the park, which leave the most relaxed movement of people and devote themselves intimacy baths, views of the surroundings and contact with water, the sky opened atrium. Its shape and facade of the building creates a barrier, but rather is permeable and in contact with their surroundings and park.
116

Confronting Manhood: The Struggle of Male Characters in the Fiction of Ernest J. Gaines.

Fay, Katie 01 May 2004 (has links) (PDF)
This study examines the African-American author Ernest Gaines's three works The Sky is Gray, In My Father's House, and A Lesson before Dying as examples of oppressed manhood, and the gradual acceptance of the characteristics of manhood in Black males. Chapter One focuses on The Sky Is Gray and follows the young hero as he makes his transition from child to a young man understanding manhood. The second chapter looks at In My Father's House, exploring the relationship between father and son. Due to his father's abandonment, the son never learns what it means to be a man. However, at the same time his son is struggling to discover his manhood, the father finally becomes a man. Finally, chapter three centers on A Lesson before Dying, showing two males can learn manhood from each other. Although both are oppressed, together they achieve the manhood that is being robbed from them.
117

Characterizing AGN Influence on the Calculated Metallicities of Adjacent Star-Forming Spaxels

Khelil, Aidan 08 November 2022 (has links)
No description available.
118

The discovery and characterization of variable stars in the All-Sky Automated Survey for SuperNovae

Jayasinghe Arachchilage, Tharindu Keshawa 27 September 2022 (has links)
No description available.
119

Sky's the limit : the operations, renovations and implications of a Montréal gay bar

Allan, James January 1997 (has links)
No description available.
120

Knowledge Exchange, Technology Transfer and the Academy

Earnshaw, Rae A. January 2012 (has links)
No / The relationship between the academy and the business community is currently perceived to be important to the future of both parties. Universities provide graduates to meet the needs and requirements of society and industry, and the latter supplies products and services to meet the needs of the market place. Whether public or private, industry increasingly seeks to use tools and techniques that increase efficiency and effectiveness, whilst at the same time maximizing quality and minimizing cost. The current trend towards companies outsourcing their R & D requirements to reduce corporate overheads and optimize staffing levels means that Universities can utilize the opportunity and bid to supply this expertise. Universities also generate their own spin-outs from intellectual property they create, as well as licensing technology to industry, rather than transferring it. However, the relationship between university and industry is not without its challenges, chief of which is the historical commitment of the academy to advance knowledge whether it is directly applicable or not. In addition, there are many fundamental and important long term research issues that many would argue are the primary duty of the academy to address, which may have no direct application in the short to medium term. This is resulting in increasing tensions in the academy, and in the priorities for national and international funding agencies. There can also be significant cultural differences and reward models between the academy and industry which give rise to difficult issues for staff at the interface. This chapter reviews the current developments and the issues at the interface between business and the academy.

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