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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.
181

Utilização da metodologia ahp para alocação de equipamentos telecomandados em sistemas de distribuição para melhoria da confiabilidade / Use for ahp methodology for allocation of remotelycontrolled devices in power distribution systems for increase reliability

Daza, Eric Fernando Boeck 22 September 2010 (has links)
In power utilities the subject reliability is a permanent worry. In this new context, some solutions have been developed and researched to an alternative to improve the performance on service restoration when there are consumers without power supply. Among possible solutions the installation of remotely-controlled switches represents a solution that has been adopted by many companies due its cost benefit. The allocation of these devices is essential to assess the different criterions and characteristics, so the use of multi-criteria decision making to evaluate these characteristics and especially to allow the measurement of expert s opinion in power distribution systems is essential. Therefore, the objective of this work is to propose a new methodology for the allocation of these devices in electric distribution systems based on AHP - Analytic Hierarchy Process decision making for validation of the best locations to install theses device. The contribution and innovation of this work consist in adding to the allocation methodology a validation of expert opinion, discarding those that present a very low consistency and thus making the final answer more exact and in accordance with the proposal, through a variation of the AHP methodology. / Em empresas de sistemas de potência a confiabilidade é uma preocupação constante. Nesse novo contexto, algumas soluções têm sido desenvolvidas e pesquisadas como alternativa para melhorar sua performance em propiciar um retorno do fornecimento de energia elétrica aos seus consumidores quando estes estão desenergizados. Dentre as soluções possíveis, a instalação de chaves telecomandadas tem representado uma solução cada vez mais adotada por várias empresas de energia devido ao seu custo benefício. Na alocação desses equipamentos é essencial considerar diferentes critérios e características, desta maneira o uso de uma metodologia de decisão multicriterial é necessário e especialmente para permitir a mensuração da opinião de especialistas do setor de sistemas de distribuição. Então, o objetivo desse trabalho é propor uma nova metodologia de alocação desses dispositivos em sistemas de distribuição de energia baseado na metodologia de tomada de decisão AHP - Analytic Hierarchy Process para validação das melhores localizações para instalar esses equipamentos. A grande contribuição e inovação desse trabalho consiste apresentar uma metodologia de alocação desses equipamentos, uma validação da opinião dos especialistas, descartando aquelas que apresentam uma baixa consistência e desta forma tornando a resposta final mais exata e de acordo com o proposto, através de uma variação da metodologia AHP.
182

Conception, synthèse et étude de nouveaux switches multimodulables

Sevez, Guillaume 18 December 2009 (has links)
Les switches multimodulables sont des systèmes qui, sous l'action d'un ou de plusieurs stimuli extérieurs, donnent naissance à un ensemble d'états aux propriétés physico-chimiques différentes. Au cours de cette thèse, plusieurs voies de synthèse permettant l'obtention d'une nouvelle famille de biphotochromes organiques constitués d'un dithiényléthène relié à une indolino[2,1-b]oxazolidine ont été mises au point. Les dithiényléthènes préparés présentent d'excellentes performances photochromiques et s'interconvertissent de façon réversible entre deux états stables thermiquement. Les 10-styryl-indolino[2,1-b]oxazolidines sont des molécules acidochromiques et doublement photochromiques par ouverture du cycle oxazolidine ou isomérisation de la double liaison. Ce système moléculaire compte jusqu'à huit états multicolores aux propriétés physico-chimiques différentes, accessibles par irradiations lumineuses et variation de l'acidité. Les propriétés ont été étudiées en solution et en matrice polymère, tous les états des biphotochromes étant caractérisés par spectroscopie d'absorption électronique et RMN. Cette thèse a été l'occasion de développer le premier système multimodulable incorporant huit états différents au sein d'une même molécule. / Multi-addressable switches are systems that give rise to a set of states with different physical-chemical properties upon the effect at least one external stimulus. During this thesis, several synthetic routes to a new family of organic biphotochromes composed of a dithienylethene linked to an indolino[2,1-b]oxazolidine have been developed. Synthesized dithienylethenes exhibit excellent photochromic properties and can be reversibly photoswitched between two thermally stable states. 10-styryl-indolino[2,1-b]oxazolidines are acidochromic molecules and photochromic by opening of the oxazolidine ring or cis/trans isomerization of the double bond. This molecular system exhibits up to eight multicoloured states with different physical-chemical properties, interchangeable by different sequences of light irradiation and pH variation steps. Properties were studied in solution and in a polymer matrix and all biphotochromes states have been characterised by electronic absorption spectroscopy and NMR. Additionally, the first multi-addressable system incorporating eight different states within the same molecule is described.
183

Paralelismo de alimentadores através de seccionadoras de vis-à-vis na rede aérea primária de distribuição. / Feeders parallelism through vis-a-vis disconnecting switches in aerial primary distribution network.

Marcos Rosa dos Santos 15 May 2008 (has links)
Um aspecto importante relacionado à operação de sistemas de distribuição é o referente à segurança nas ações de restabelecimento pós-perturbações, em manobras emergenciais e programadas, onde necessite de transferência de cargas entre alimentadores aéreos primários de uma mesma subestação ou para uma subestação adjacente, de forma segura e confiável. Devem-se observar os requisitos de carregamento, tensão a nível sistêmico, proteção, entre outros. Atualmente as decisões e tomadas de ações referentes às manobras necessárias para os remanejamentos de cargas são de competência dos operadores que atuam nas salas de controle de operações e, em muitos casos, respaldadas somente na experiência de cada operador, acumulada ao longo do tempo. Este trabalho visa o estudo dos fenômenos físicos envolvidos em situações que coloquem alimentadores aéreos primários de distribuição em paralelo ou mesmo quando se forme uma configuração em anel fechado. Estas manobras podem ser executadas através de alimentadores e transformadores distintos, de mesma potência ou de potências diferentes, estabelecendo diretrizes e respaldando os operadores das salas de controle em situações de emergência, urgência ou programadas no sistema aéreo de distribuição. O objetivo principal é oferecer informações técnicas, possibilitando as tomadas de decisões mais adequadas na coordenação de manobras no sistema aéreo de distribuição, em tempo real. Cada uma delas tem condições que se pode considerar como a mais adequada para a execução dos procedimentos estabelecidos, porém sem os principais subsídios técnicos. Desta forma, algumas variáveis como tensão mínima, limites de carregamento de equipamentos, ângulo de fase dos transformadores, restrições operativas do sistema e de consumidores, devem ser aplicadas em tempo real para a tomada de decisão por parte dos operadores do sistema elétrico. / An important aspect related to the distribution systems operation concerns the safety required in the post-disturbances restorement actions or in the emergency and scheduled maneuvers, which involve the need for load transfer between primary overhead feeders of a same sub-station or for an adjacent sub-station, in a safe and reliable way, complying with the loading requirements, voltage at systemic level and protection, among others. Currently the decisions and taking actions related to the necessary maneuvers to carry out the load transfers are responsibility of the operators who work in the operations control rooms, and in many cases, only endorsed by each operator´s own experience, gathered along the time. This paper aims at the study of the involved physical phenomena in situations that place distribution primary overhead feeders in parallel or even when a configuration in closed ring is formed, via distinct transformers and feeders of same or different powers, establishing guidelines and endorsing the control rooms operators in emergency, urgency or scheduled situations in the distribution overhead system. The main objective is to provide technical information, enabling more adequate taking decisions in the distribution overhead system maneuvers coordination, in real time. Each of them has conditions that can be considered the most adequate to carry out the established procedures, however without the main technical information. Thus, some variables such as minimum voltage, equipment loading limits, transformers´ phase angle, the operational restrictions of the system and customers must be applied in real time for the taking decision by the electrical system operators.
184

Helicenes for chiral molecular switches, magnetic materials, and chiral fullerene derivatives / Hélicènes pour les commutateurs moléculaires chiraux, les matériaux magnétiques et le fullerène chiral dérivés

Ouyang, Jiangkun 13 December 2017 (has links)
Dans ce travail de thèse, nous avons d'abord développé deux études basées sur des unités dites ''stilbène rigide'' qui sont connues pour s'interconvertir de manière réversible entre deux formes trans et cis grâce à la lumière. La première étude correspond à des photocommutateurs chiraux à base d'hélicènes, l'autre à des complexes photocommutables alcynyles d'or(I). Ensuite, nous avons examiné la synthèse et la caractérisation de complexes de Dy(III) à base d'hélicène-bipyridine comme nouveaux types d'aimants moléculaires (SMM) chiraux et comparé la différence des propriétés magnétiques entre les SMM racémique et énantiopurs. Enfin, nous avons développé la première utilisation de la cycloaddition réversible d'hélicènes racémiques sur le [60]fullerène et de sa rétrocycloaddition ultérieure comme une stratégie alternative efficace pour le dédoublement énantiomérique d'un hélicène-carboxaldéhyde. / In this PhD work, we firstly developed two studies based on the so-called ''stiff stilbene'' units that are known to reversibly interconvert between two trans and cis forms through light. The first study corresponds to photoresponsive chiral switches based on helicenes, the other one to photoresponsive gold(I) complexes. Then, we dealt with the synthesis and characterization of helicene-bipyridine based Dy(III) complexes as novel kinds of chiral single molecule magnets (SMMs) and compared the difference of the magnetic properties between racemic and enantiopure SMMs. Finally, we developed the first use of the reversible sterodivergent cycloaddition of racemic helicenes onto [60]fullerene with its subsequent retro-cycloaddition as an efficient alternative strategy for the enantiomeric resolution of a helicene-carboxaldehyde.
185

A wired-AND transistor: Polarity controllable FET with multiple inputs

Simon, M., Trommer, J., Liang, B., Fischer, D., Baldauf, T., Khan, M. B., Heinzig, A., Knaut, M., Georgiev, Y. M., Erbe, A., Bartha, J. W., Mikolajick, T., Weber, W. M. 29 November 2021 (has links)
Reconfigurable field effect transistors (RFET) have the ability to toggle polarity between n- and p- conductance at runtime [1], [2]. The here presented multiple independent gate (MIG) RFET expands the device functionality by offering additional logical inputs, valuable for e.g. efficient XOR or majority gate implementations [3], [4] or the here originally presented multiplexer circuit. Moreover,https://inspec.iet.org/ideas/#controlled-terms for the first time with a top-down RFET approach equal ON-currents are obtained for every configuration while requiring only one supply voltage (VDD).
186

Computing with Ferroelectric FETs

Aziz, Ahmedullah, Breyer, Evelyn T., Chen, An, Chen, Xiaoming, Datta, Suman, Gupta, Sumeet Kumar, Hoffmann, Michael, Hu, Xiaobo Sharon, Ionescu, Adrian, Jerry, Matthew, Mikolajick, Thomas, Mulaosmanovic, Halid, Ni, Kai, Niemier, Michael, O'Connor, Ian, Saha, Atanu, Slesazeck, Stefan, Thirumala, Sandeep Krishna, Yin, Xunzhao 30 November 2021 (has links)
In this paper, we consider devices, circuits, and systems comprised of transistors with integrated ferroelectrics. Said structures are actively being considered by various semiconductor manufacturers as they can address a large and unique design space. Transistors with integrated ferroelectrics could (i) enable a better switch (i.e., offer steeper subthreshold swings), (ii) are CMOS compatible, (iii) have multiple operating modes (i.e., I-V characteristics can also enable compact, 1-transistor, non-volatile storage elements, as well as analog synaptic behavior), and (iv) have been experimentally demonstrated (i.e., with respect to all of the aforementioned operating modes). These device-level characteristics offer unique opportunities at the circuit, architectural, and system-level, and are considered here from device, circuit/architecture, and foundry-level perspectives.
187

Rekonstrukce železniční stanice Lipová Lázně / Upgrading of Lipová Lázně Railway Station

Kopecká, Denisa January 2018 (has links)
The master's thesis deals with reconstruction design of Lipová Lazně railway station. The main goal is to design new platforms suitable for passengers with reduced mobility and orientation and valid standart. Another goal is to increase line speed. Part of the thesis includes modifications of railway superstructure, substructure and drainage system of the station.
188

Rekonstrukce železniční stanice Trutnov hl.n / Upgrading of Trutnov hl.n. Railway Station

Král, Vladimír January 2015 (has links)
The aim of the diploma thesis is a design of the reconstruction railway station Trutnov main station for compliance with current operations and especially with regard to persons with reduced mobility. So it was necessary to design the platform edge with a height of 550 mm above rail level. The design also deals with the drainage of reconstructed tracks and sidings connection.
189

Návrh rekonstrukce železničních stanic Ždírec nad Doubravou a Hlinsko v Čechách / Design of Reconstruction of Ždírec nad Doubravou Railway Station and Hlinsko v Čechách Railway Station

Fabiánová, Lucie January 2015 (has links)
The aim of the diploma thesis is to design of reconstruction of the Ždírec nad Doubravou railway station and Hlinsko v Čechách railway station, and to allow access for persons with reduced mobility. Resolving a modification of the track (reconstruction gridiron), design the reconstruction of the substructure and drainage railway stations.
190

Návrh modernizace železniční stanice Valašské Meziříčí / Design of modernization of Valašské Meziříčí Railway Station

Málek, Jiří January 2016 (has links)
The theme of this thesis is to design modernization of Valašské Meziříčí Railway Station. This thesis includes reconstruction of both station heads and the design of the platforms for the safe movement of persons with reduced mobility with seven platform edges in total. The thesis deals with the construction of the railway superstructure and substructure, including drainage.

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