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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.
221

Aplicação da técnica de decomposição de Benders para cálculo da reserva girante considerando a curva de capabilidade dos geradores

Aleixo, Marcelo de Souza 29 June 2018 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-11-06T17:02:42Z No. of bitstreams: 1 marcelodesouzaaleixo.pdf: 2786878 bytes, checksum: dfbd57d9b8be2153917fe637209df9f0 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-11-23T13:19:16Z (GMT) No. of bitstreams: 1 marcelodesouzaaleixo.pdf: 2786878 bytes, checksum: dfbd57d9b8be2153917fe637209df9f0 (MD5) / Made available in DSpace on 2018-11-23T13:19:16Z (GMT). No. of bitstreams: 1 marcelodesouzaaleixo.pdf: 2786878 bytes, checksum: dfbd57d9b8be2153917fe637209df9f0 (MD5) Previous issue date: 2018-06-29 / Este trabalho apresenta uma metodologia para cálculo da reserva girante do sistema elétrico de potência. A proposta inclui a curva de capabilidade dos geradores bem como cenários de carga e de geração eólica bem como falhas no sistema de geração e transmissão. O fluxo de potência ótimo é utilizado para determinar as condições iniciais do sistema, caso base. A partir daí o problema é resolvido de forma interativa entre dois estágios em umaestruturamestreeescravo: Oproblemamestreutilizaprogramaçãolinearinteirapara determinar o número mínimo de unidades de geração disponíveis (ligadas); O problema escravo verifica se o número de unidades ligadas é suficiente para operação do sistema. Este problema corresponde ao Fluxo de Potência Ótimo com o objetivo de obter o mínimo corte de carga para cada condição operativa. O corte de Benders é produzido para cada cenário, altenativamente, será investigado a utilização da média dos cortes de Benders. O processo termina quando não ocorrer corte de carga. A metodologia é testada utilizando um sistema teste de 4 barras como exemplo tutorial e também aplicada nos sistemas IEEE 14, 39 e 118 barras. / This work presents a methodology for calculating the spinning reserve of the electric power system. The proposal includes the capability curve of the generators as well as errors of prediction of load, wind generation, failures in the system of generation and transmission. The optimal power flow is used to determine the initial conditions of the system, base case. From this point the problem is solved interactively between two stages in a master and slave structure: The first uses integer linear programming to determine the minimum number of available (turn on) generation units; The second corresponds to the Optimum Power Flow with the purpose of obtaining the minimum load shedding for each operative condition. The cut of Benders is produced for each scenario, alternatively, the use of the average of cuts will be investigated. The process ends when there is no load shedding. The methodology is tested using a 4-bar test system as a tutorial example and also applied in IEEE systems 14, 39 and 118 bars.
222

Influence de la nanostructuration sur les propriétés thermoélectriques des matériaux masifs de type p à base de (Bi, Sb, Te) / Influence of nanostructuring on thermoelectric properties of p-type bulk materials based on (Bi, Sb, Te)

Ohorodniichuk, Viktoriia 18 December 2014 (has links)
Ce travail a été réalisé en collaboration avec EDF R&D, dans le cadre d’une convention CIFRE-ANRT, l’objectif étant d’améliorer le coefficient de performance de pompes à chaleur thermoélectriques (PACTEs) pour des "Bâtiments Basse Consommation". Les PACTEs présentent de nombreux avantages environnementaux, le désavantage étant leur faible performance. Ainsi l'objectif de ce travail a été d'examiner la possibilité d'améliorer, par nanostructuration les performances des semi-conducteurs utilisés dans les modules thermoélectriques des PACTEs. Nos travaux se sont concentrés sur les solutions solides à base de Sb2-xBixTe3, celles-ci étant, selon l’état-de-l’art, les plus performantes pour l’application visée. La nanostructuration a été réalisée par la technique de trempe sur roue (technique de refroidissement rapide de liquides) de matériaux synthétisés auparavant à l'état liquide dans des tubes en quartz. Les moyens de caractérisation (DRX, MEB, MET, METHR) ont permis de corréler les changements structurels avec la variation des propriétés thermiques et électriques (le pouvoir thermoélectrique, la résistivité électrique, l'effet de Hall, la conductivité thermique) mesurées sur de larges gammes de température (5-460 K). L'influence favorable de la nanostructuration par la diminution de conductivité thermique a été prouvée. Nous avons montré la forte dépendance des propriétés thermoélectriques des matériaux étudiés avec la concentration de défauts et la stœchiométrie. Le dopage avec du Te a été examiné comme une possibilité de contrôler le niveau de la concentration des porteurs de charge. L'idée de créer des niveaux d'impuretés résonantes par un dopage au Sn s’est montrée infructueuse, vraisemblablement en raison de la structure de bande complexe du composé ternaire. Néanmoins, des valeurs du facteur de mérite adimensionel ZT de près de 1,2 ont été obtenues pendant ce travail / This work results from the collaboration between IJL and EDF R&D performed under a CIFRE-ANRT convention, in order to improve the coefficient of performance of thermoelectric heat pumps (THPs). THPs attracted attention of EDF due to its numerous environmental advantages, but the main drawback remains its low performance. The objective of our work was thus to investigate the possibility to enhance the performance of the semiconductors used in the thermoelectric modules of the THPs, by nanostructuration. The research was concentrated on the Sb2-xBixTe3-based solid solutions, the most effective materials for the application sought. The nanostructuration was performed by applying the melt-spinning technique (rapid quenching from a melt on a water-cooled cupper wheel) to the material synthesised beforehand from liquid state in quartz tubes. The means of characterisation (XRD, SEM, TEM, HRTEM) gave the possibility to correlate the structural changes with the variation of the thermal and electrical properties (thermoelectric power, electrical resistivity, Hall effect, thermal conductivity) measured over a wide temperature range (5-460 K). The favourable influence of nanostructuration through the decreasing of thermal conductivity was proved. A high dependence of the thermoelectric efficiency of the studied materials on the concentration of defects and stoichiometry is shown. Doping with Te was investigated as a possibility to control the resulting level of the charge carrier concentration. The idea of creating resonant impurity levels by Sn-doping was shown to be non-conclusive presumably due to the complex band structure of the ternary compounds. Nevertheless, relatively high values of the dimensionless TE figure of merit, close to 1.2, were obtained during this work
223

Soft Revolvers et les interfaces créées sur mesure : la performance de musique numérique dans une perspective d’œuvre totale

Bleau, Myriam 01 1900 (has links)
Cette version du mémoire a été tronquée des éléments de composition originale. Une version plus complète est disponible en ligne pour les membres de la communauté de l’Université de Montréal et peut aussi être consultée dans une des bibliothèques UdeM. / Ce texte présente le processus de composition ayant mené à la création de la performance Soft Revolvers. Cette œuvre repose sur la conception d’interfaces sur mesure, soit quatre toupies lumineuses évoquant les tables tournantes. Je situe la création d’un tel dispositif, connoté et totalement intégré au propos artistique, dans la continuité historique du Gesamtkunstwerk (œuvre totale). Cette perspective englobante permet de questionner tous les aspects qui affectent la réception d’une œuvre. J’exposerai donc comment la lutherie utilisée, la gestuelle développée, la forme musicale et la scénographie ont été articulées autour d’un concept central dans la performance Soft Revolvers. Je présenterai finalement deux autres œuvres connexes, la performance Tempo Deluxe, qui utilise les mêmes interfaces de toupies, et la pièce Lumens&Profits, qui revisite les mêmes thématiques et techniques de composition dans une version fixée. Cette mise en parallèle permettra de mieux cerner les limitations impliquées par la spécificité des interfaces, tout en faisant ressortir l’efficacité du dispositif créé sur mesure dans le contexte numérique. / This text examines the composition process leading to the creation of the performance Soft Revolvers. The work is based on performance specific interfaces: four luminous spinning tops that evoke turntables. These connoted devices, fully integrated in the artistic discourse, are located within the historic continuum of the Gesamtkunstwerk (total work of art). This holistic perspective allows the renegociation of all the aspects that might influence the reception of a performance. Each of these aspects - the digital instrumentation, the gestural language, the musical form and the scenography - is discussed and articulated around the central concept in Soft Revolvers. Finally, two related works are presented, the performance Tempo Deluxe, which uses the same spinning top interfaces, and the piece Lumens&Profits, which explores the same thematic material as Soft Revolvers in a fixed version. Comparing these works allows a better delineation of the limitations implied by the interfaces' specificity, while confirming the effectiveness of the performance specific device in the digital realm.
224

Technology of monofilamentous fibers based on oxidized hyaluronic acid / Technology of monofilamentous fibers based on oxidized hyaluronic acid

Běťák, Jiří January 2016 (has links)
Předkládaná dizertační práce se zabývá vývojem technologie výroby nového typu biodegradabilních vláken na bázi oxidované kyseliny hyaluronové. V rámci práce je postupně představován vývoj jednotlivých jednotkových operací výroby, jejichž správné porozumění a schopnost jejich řízení jsou klíčové pro žádaný chod celé vícestupňové technologie. V rámci práce je představen nezbytný vývoj technologického zařízení, průběžně konstruovaného pro účely laboratorního testování a následně až po samotnou linku pro finální výrobu vláken, která byla realizována v roce 2015. V rámci dizertační práce jsou dále navrhovány možnosti dodatečné chemické úpravy vláken s ohledem na zvyšování jejich stability ve vlhkém prostředí. S ohledem na cílené aplikace vláken pro vnitřní chirurgické implantace, jsou v práci vlákna též hodnocena z hlediska jejich materiálové biokomaptibility (toxicity).
225

Studium přípravy a struktury nanovláken anorganických a organických biomateriálů / Study of preparation and structure of nanofibers of inorganic and organic biomaterials

Ručková, Jana January 2014 (has links)
The aim of this Master’s thesis is to investigate the preparation and structure of nanofibres of inorganic and organic biomaterials. Nanofibres of polycaprolactone, chitosane and their composites with hydroxyapatite particle were prepared by centrifugal force spinning process, which uses centrifugal forces for nanofibres spinning. Designed nanofibres can be used in bone tissue engineering. Experimental activity has started with synthesis of hydroxyapatite nanoparticles and preparation of polymer solutions and composite suspensions at different concentrations. The solutions and the suspensions were characterized by density and viscosity which were changed in dependence on temperature and polymer concentration. The solutions and the suspensions were spun at varying speeds and using two different sizes of collectors. The dependence of spinneret head revolution speed, size of collectors and polymer concentration on nanofibres diameter was studied. Biological activity of polycaprolactone and hydroxyapatite/polycaprolactone nanofibres was tested by means of SBF.
226

Processing and Characterization of Nanocellulose Composites: The Leap from Poly(lactic acid) to Polyamide 6

Caitlyn Michelle Clarkson (8774828) 02 May 2020 (has links)
This disseration covers the processing and characterization of nanocellulose polymer composites. In this disseration, two fiber spinning methods were developed to create high stiffness nanocomposite fibers from renewably-sourced materials and the properties of these nanocomposites were evaluated. Additionally, bulk nanocomposites were created and some of the properties of these materials, for different types of nanoparticles, are also discussed. Evaluation of nanocellulose as a nucleation agent in poly(lactic acid) is also presented for very small concentrations of nanocelluloses in a plasticized polymer.
227

Inteligentní nanovlákna funkcionalizovaná růstovými faktory a krevními deriváty pro dermatologické aplikace / Intelligent nanofibres functionalized with growth factors and blood derivatives for dermatology applications

Vocetková, Karolína January 2019 (has links)
Platelet derivatives are an attractive source of natural growth factors and they are widely used in various tissue engineering and regenerative medicine applications. The aim of this study was to optimize cell culture conditions using platelet lysate and to develop platelet-functionalized fibrous scaffolds as a controlled drug delivery system for native growth factors. Fibrous scaffolds were prepared by electrostatic and centrifugal spinning of PCL and they were functionalized by the platelets by surface adhesion or their encapsulation using emulsion spinning techniques. The cell culture study determined the 7% platelet lysate to be the optimum concentration as a medium supplement in keratinocyte and fibroblast culture. Additionally, following surface adhesion of the platelets to PCL electrospun nanofibres, the platelets were activated due to their contact with the nanofibre nanotopography, resulting in formation of fibrin network. Fibrin served as a reservoir of the growth factors, prolonging the half-time of EGF release to 1.7 days. Such platelet-functionalized samples fostered proliferation of keratinocytes, fibroblasts and melanocytes. Furthermore, adhesion of platelets to centrifugally spun nanofibrous scaffolds resulted in almost two-fold increase in the amount of immobilized platelet-derived...
228

Entwicklung von Fertigungstechnologien zur Herstellung biomimetischer faserbasierter Scaffolds aus Kollagen für das Tissue Engineering und die regenerative Medizin

Tonndorf, Robert 14 June 2022 (has links)
Die enormen Fortschritte und Erkenntnisse der Medizin und der damit einhergehenden gestiegenen mittleren globalen Lebenserwartung von indes knapp 75 Jahren fußen auch auf den medizinischen Entwicklungen des 20. Jahrhunderts, da durch diese z. B. infektiöse und onkologische Erkrankungen, Diabetes, Bluthochdruck, Herzinsuffizienz, Magengeschwüre, Depressionen, Hämophilie und andere Krankheiten erfolgreich therapiert werden können. Die entwickelten Therapiemethoden beruhten im Wesentlichen auf chirurgischen und intensivmedizinischen Neuerungen, chemischen Wirkstoffen, belastungsfähigen Implantaten und extrakorporalen Systemen. Im 21. Jahrhundert hingegen sind medizinische Neuerungen im molekularbiologischen Bereich zu erwarten, wie beispielsweise in der Zellbiologie, DNA-Analyse und -Transfer oder in der regenerativen Medizin. In Letzterer werden autologe regenerative Mechanismen als therapeutisches Prinzip genutzt, um funktionsgestörte Zellen, Gewebe und Organe entweder durch den biologischen Ersatz oder durch die Anregung körpereigener Regenerations- und Reparaturprozesse zu erhalten bzw. wiederherzustellen.
229

Peptide and Protein Supramolecular Assemblies Studied by Solid-State NMR Spectroscopy

Qi, Zhe 07 September 2017 (has links)
No description available.
230

固体高分解能NMR Magic Angle Spinning 法の高度化

松永, 達弥 23 May 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20550号 / 理博第4308号 / 新制||理||1618(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 竹腰 清乃理, 教授 吉村 一良, 教授 松本 吉泰 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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