14,516 research outputs found
Retificador trifásico buck-boost de estágio único
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica.Este trabalho apresenta uma nova topologia de retificador trifásico de estágio único com característica Buck-Boost. Inicialmente é apresentada uma revisão bibliográfica envolvendo as publicações mais relevantes na área de estudo. Na sequencia são apresentadas a motivação para o trabalho e as contribuições da Tese. A topologia proposta é apresentada sendo descritas a sua origem e seus modos de operação de interesse. São analisados então os modos de condução descontínua (MCD) e contínua (MCC). No MCC são analisados os modos de operação Buck, Buck+Boost e Boost. As etapas do estudo de cada modo de operação compreendem a descrição das etapas de operação, análise teórica estudos por simulação numérica, definição das equações de projeto e resultados experimentais.This work presents a new topology of three-phase rectifier with singlestage and Buck-Boost characteristic. Initially a literature review is presented which brings the most important publications in the study area. Following it is presented the motivation for the work and the contributions of this thesis. The proposed topology is then presented, with descriptions of their origin and their operation modes of interest. Are then analyzed the discontinuous (DCM) and continuous (CCM) conduction modes. At MCC, we analyze the operation modes Buck, Boost and Buck + Boost. The study stages of each mode of operation include the description of the operation stages, theoretical analysis, numerical simulation studies, definition of design equations and experimental results
Passing the buck
No full textShifting the responsibility for a necessary but costly action to someone else is often called Passing the Buck. Examples of such behavior in politics are environmental and budget problems which are left to future generations. Small group examples are (not) washing the dishes or (not) dealing with a difficult customer. Under the assumption of altruistic preferences, rational behavior in this game is derived and confronted with experimental data. By comparison, the sequence of possible decision makers in the normal Passing the Buck game is substituted with an expert who alone is competent to fix the problem. It turned out that the marginal probabilities of shifting the responsibility are in good accordance with the theoretical model, although with completely different parameter distributions for experts and non-experts. The structure of the individual decisions, however, is best described by a random parameter model (Cox et al., 2007). --public goods,volunteer's dilemma,responsibility
Letter to Sonora Dodd from Buck P. Campbell, August 13, 1976
No full textLetter to Sonora Dodd from Buck P. Campbell, with envelope. Buck Campbell was a friend of Mrs. Dodd and her family.https://digitalcommons.whitworth.edu/fathers-day-correspondence/1031/thumbnail.jp
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[News Clip: Pearl Buck]
No full textVideo footage from the WBAP-TV station in Fort Worth, Texas to accompany a news story about an author, who came to Dallas to claim her prizes. Novelist Pearl Buck arrived for the 6th annual Club Woman's Forum
Retificador buck trifásico unidirecional PWM isolado em alta-frequência por único estágio
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2009Descreve-se uma nova topologia de conversor CA-CC trifásico isolado em alta-frequência por único estágio de potência. O novo conversor é constituído de um retificador Buck unidirecional trifásico associado a um transformador forward/flyback com desmagnetização na carga. Para a exploração da nova topologia foram realizados estudos sobre retificadores Buck, algumas técnicas populares de modulação SPWM escalar, uma técnica clássica de filtragem das harmônicas das correntes de entrada e uma técnica de modelagem por espaço-de-estados e controle contínuo do retificador Buck em sistema de coordenadas dq obtidas por transformação de Clarke/Park. Para a obtenção da isolação em alta-frequência sem conversores adicionais foram estudados os princípios de operação do conversor forward/flyback em modo de condução descontínuo para posterior integração do transformador ao retificador trifásico. Os conhecimentos obtidos foram concentrados no retificador Buck trifásico isolado em altafrequência onde foram exploradas a modulação da ponte retificadora, os estados de operação associados ao transformador e a desmagnetização na carga. Ainda, foram obtidos os modelos em espaço-de-estados em coordenadas dq para o retificador Buck com transformador e projetados compensadores PI contínuos para o controle pela tensão na carga. Para a comprovação do conceito da topologia proposta foi projetado e implementado um protótipo de 2;5 kW para conexão em rede trifásica sem neutro de 220 V e tensão de 48 V para a carga regulada por circuito controlador digital baseado na arquitetura de baixo custo dsPIC.This work presents a new topology for an AC-DC three-phase converter with single-stage high-frequency isolation. The new converter is composed of an unidirectional three-phase Buck rectifier and a forward/flyback transformer with demagnetization through the load. The study of Buck rectifiers principles has been performed as a basis to develop the new topology. The scalar SPWM modulation techniques, the classic design of filters to input currents and a state-space modeling technique at dq components to design the feedback control for a Buck rectifier have been studied. The forward/flyback converter operating at discontinuous conduction mode has been studied to allow a high-frequency isolation to the Buck rectifier without the cascade of extra switched converters. The three-phase Buck rectifier with high-frequency isolation has been analyzed regarding pulse width modulation, operational states and requirements for demagnetization through the load. Moreover, the state-space models at dq components have been derived and standard PI regulators have been designed to control the proposed rectifier. The validation of the proposed topology has been performed on an experimental prototype with the following specification 220 V three-wires mains source and 2:5 kW at 48 V output regulated by a digital control based on dsPIC low cost architecture
Lepidosina Marshall & Buck 2007
No full textGenus <i>Lepidosina</i> Marshall & Buck, 2007 <p> <i>Lepidosina</i> Marshall & Buck, 2007 in MARSHALL at al. (2007): 573 (feminine). Type species: <i>Leptocera</i> (<i>Scotophilella</i>) <i>gibba</i> Spuler, 1925, original designation. – MARSHALL et al. (2007): 573–599 [diagnosis, phylogeny, COI sequencing, key, illustr.].</p> <p> <i>Lepidosina angusticercus</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Brazil, British Virgin Is., Dominica, Dominican Republic, Ecuador, Grenada, Panama, Peru, Puerto Rico.</p> <p> <i>Lepidosina angusticercus</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 581 [both sexes, key, illustr.]. Type locality: Grenada, Concord Falls, Nutmeg Plantation. HT male (DEBU).</p> <p> <i>Lepidosina argentinensis</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Argentina.</p> <p> <i>Lepidosina argentinensis</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 582 [both sexes, key, illustr.]. Type locality: Argentina, Salta, La Caldera, Camino la Cornisa [1,500 m]. HT male (DEBU).</p> <p> <i>Lepidosina cubensis</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Cuba.</p> <p> <i>Lepidosina cubensis</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 584 [both sexes, key, illustr.]. Type locality: Cuba, Santiago, Gran Piedra, Segundo chorroito [600 m]. HT male (DEBU).</p> <p> <i>Lepidosina evanescens</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Bolivia, Colombia, Costa Rica, Ecuador, Peru, Venezuela.</p> <p> <i>Lepidosina evanescens</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 585 [both sexes, key, illustr.]. Type locality: Ecuador, Esmeraldas, 11 km SE San Lorenzo, La Chiquita [5 m]. HT male (DEBU).</p> <p> <i>Lepidosina gibba</i> (Spuler, 1925). <b>Distr.:</b> Nearctic: USA (FL); Neotropical: Dominican Republic, Haiti, Jamaica.</p> <p> <i>Leptocera</i> (<i>Scotophilella</i>) <i>gibba</i>. – ROHÁČEK et al. (2001): 289 [catalog, as species incertae sedis].</p> <p> <i>Lepidosina gibba</i>. – MARSHALL et al. (2007): 586 [generic combination, redescription, phylogeny, illustr.].</p> <p> <i>Lepidosina inaequalis</i> (Malloch, 1914). <b>Distr.:</b> Nearctic: USA (AL); Neotropical: Belize, Costa Rica, El Salvador,? Galápagos Is. (Ecuador), Mexico (BCS, JAL, MOR, SLP, SON), Venezuela.</p> <p> <i>Leptocera</i> (<i>Limosina</i>) <i>inaequalis</i>. – ROHÁČEK et al. (2001): 289 [catalog, as species incertae sedis].</p> <p> <i>Lepidosina inaequalis</i>. – MARSHALL et al. (2007): 588 [generic combination, redescription, phylogeny, illustr.].</p> <p> <i>Lepidosina multispinulosa</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Ecuador, Peru.</p> <p> <i>Lepidosina multispinulosa</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 590 [male, key, illustr.]. Type locality: Ecuador, Napo, Yasuní National Park, Yasuní Research Station. HT male (ZMUC).</p> <p> <i>Lepidosina platessa</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Bolivia.</p> <p> <i>Lepidosina platessa</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 592 [male, key, illustr.]. Type locality: Bolivia, Santa Cruz, Portrerillo, Terevinto. HT male (DEBU).</p> <p> <i>Lepidosina proxineura</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Brazil.</p> <p> <i>Lepidosina proxineura</i> Marshall & Buck, 2007 in MARSHALL et al.(2007): 593 [male, key, illustr.]. Type locality: Brazil, Rio de Janeiro, Represa dos Ciganos. HT male (UNSP).</p> <p> <i>Lepidosina quadrisquamosa</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Venezuela.</p> <p> <i>Lepidosina quadrisquamosa</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 594 [both sexes, key, illustr.]. Type locality: Venezuela, Aragua, El Limón, Pozo del Diablo [570 m]. HT male (DEBU).</p> <p> <i>Lepidosina rutricauda</i> Marshall & Buck, 2007. <b>Distr.:</b> Neotropical: Colombia, Ecuador, Peru.</p> <p> <i>Lepidosina rutricauda</i> Marshall & Buck, 2007 in MARSHALL et al. (2007): 597 [both sexes, key, illustr.]. Type locality: Ecuador, Napo, Jatun Sacha Reserve, 6 km E Misahuallí [450 m]. HT male (DEBU).</p>Published as part of <i>Marshall, Stephen A., Roháček, Jindřich, Dong, Hui & Buck, Matthias, 2011, The state of Sphaeroceridae (Diptera: Acalyptratae): a world catalog update covering the years 2000 - 2010, with new generic synonymy, new combinations, and new distributions, pp. 217-298 in Acta Entomologica Musei Nationalis Pragae 51 (1)</i> on page 244, DOI: <a href="http://zenodo.org/record/5327684">10.5281/zenodo.5327684</a>
Letter from Alonzo Buck to Alden Partridge, 5 November 1828
No full textAlonzo P. Buck writes to thank Alden Partridge for providing him an education; discusses his current studies; is to teach school at Randolph, Vermont; his brother wishes him to join a profession soon and has hinted he may help him obtain a midshipman's warrant; gives Vermont news, including a recent flood and the election of Samuel C. Crafts as governor of Vermont. Letter is sent with frank of Daniel Azro Ashley Buck.Transcription by Raymond Bouchard. Transcriptions may be subject to error
Letter from Alonzo Buck to John Partridge, 23 March 1827
No full textAlonzo P. Buck writes from Chelsea, Vermont, to John Milton Partridge in Middletown, Connecticut; he wishes to join Alden Partridge's academy in Middletown as a musician; keeps getting equivocal responses from Alden Partridge about assisting him in procuring an education; would like to see Partridge in person and speak with him. Due to construction of the letter, words in the gutter of page 4 may be illegible.Transcription by Renee Townsley. Transcriptions may be subject to error
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