134,508 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
Oral History Interview with Homer Buck & Dub Ramsel, June 21, 2003
No full textThe National Museum of the Pacific War presents an interview with Homer Buck and Dub Ramsel. Buck joined the Marine Corps in October of 1942, and served as a B-25 pilot. He was assigned as a replacement on Mindanao, Philippines. He completed patrol missions, searching for Japanese PT boats. Buck was discharged in early 1946. Ramsel was called to active duty in September of 1942. He received his wings and commission in August of 1943, and served as a Corsair pilot. In early 1944, Ramsel served with Marine Fighting Squadron 215 (VMF-215). He deployed to Hawaii as a replacement, completed around 900 hours of flight time, though never participated in any war campaigns. Ramsel was discharged in October of 1945
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
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
La rinascita di Pearl Buck
No full textBettina Mottura has translated an article written by Nan Qiao 南侨, pseudonym of a Chinese scholar and columnist, published by the Nanfang zhoumo 南方周末 in 2017 and has written some introductory notes to the translation. The article testifies to the role of Pearl Buck as a key figure in today cultural discourse in China. It also offers a representation of the writer strongly influenced by the contemporary Chinese context, reconstructing an idealized image of Pearl Buck, which is only partially rooted in the historical reality of the writer's biography or in the literary reality of her works. The article also refers to a galaxy of values and meanings that the Chinese cultural world associates to the American writer. The translation is published with an introductory note and an apparatus of comments that aim to highlight the most salient aspects of the Chinese text and to contextualise it
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>
buck v
No full textbuck v'To purloin; to collect or gather surreptitiously; STING'.See cited quotation.DNE Sup _DNE_ suggests nothing in the headnote. But cp. _EDD_ buck sb� and _v� 6_. 'To pull out, extract'. Dev. cite , extracting teeth; n.Dev. 'To buck corn, to pick out all the grain in the ground. GROSE (1790) MS add.note that all the Nfld cites refer to such things as carrots, cherries, fish, and the like, with the notion of selective 'picking', 'extraction'.G. M. Story JUL. 21 1988 WKUsed IUsed INot usedCard is stamped DNE Sup, but head word only appears in DNE I
Traduzione e ricezione dell’opera di Pearl S. Buck in Cina
No full textThe Translation and Reception of Pearl S. Buck in China is a process which started in the 1930s and lasts until today. Its development was entangled with the cultural history of China and involved different actors such as: the writer herself, the translators (often representing a cultural elite) and the public (the readers). Drawing on Chinese academic sources, this paper highlights and discusses different phases in this process
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