Switched Current
Mostrando 1-12 de 32 artigos, teses e dissertações.
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1. MODULADOR SI-ΣΔ CASCATA 2-2 EMPREGANDO ARQUITETURA DE BAIXA DISTORÇÃO APLICADO À CONVERSÃO AD / (A CASCADE 2-2 SI-ΣΔ MODULATOR USING A LOW-DISTORTION TOPOLOGY APPLIED TO AD CONVERSION
A crescente complexidade dos circuitos digitais força o uso de novas tecnologias de fabricação. A mudança para tecnologias mais avançadas tem como vantagem a redução do tamanho do circuito e a diminuição do consumo de energia aliados ao aumento da velocidade de operação. Grande parte das operações envolvendo processamento de sinais migraram para
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/03/2012
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2. A study of convective flux schemes for aerospace flows
This paper presents the effects of some convective flux computation schemes on boundary layer and shocked flow solutions. Second-order accurate centered and upwind convective flux computation schemes are discussed. The centered Jameson scheme, plus explicitly added artificial dissipation terms are considered. Three artificial dissipation models, namely a sca
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012-09
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3. Control strategies applied for reducing the vibration and torque ripple of a special Switched Reluctance Motor
Despite its robustness the Switched Reluctance Motors (SRMs) present some inconvenient drawbacks as a major torque ripple, vibration and acoustic noise when compared to other types of motors. These characteristics are usually related to factors such as the salient poles in the stator and in the rotor, the switched feeding and the control strategy imposed by
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-06
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4. PROCESSAMENTO DE SINAIS ANALÓGICOS AMOSTRADOS UTILIZANDO TÉCNICAS DE CHAVEAMENTO A CAPACITOR E A CORRENTE APLICADOS À CONVERSÃO AD SIGMA DELTA
Circuitos de amostragem e retenção de sinais analógicos são comumente implementados com técnicas de chaveamento de capacitores (Switched Capacitor SC). Circuitos SC empregam o armazenamento de cargas em um capacitor linear para representar um sinal sob a forma de tensão. Amplificadores Operacionais (AmpOps) são usados para transferir essa carga de um
Publicado em: 2009
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5. Desenvolvimento de uma plataforma digital para a minimização da vibração e da ondulação de torque de um motor de relutância chaveado. / Development of a digital test setup for minimizing the torque ripple and the vibration of a swiched reluctance motor.
The initial purpose of this study is to develop a methodology of analysis of the torque ripple of a two-phase special SRM 4/2 using acceleration experimental data. In order to validate the proposed method, acceleration experimental results are presented, these results were obtained with two rotors: the reference rotor and the optimized rotor. Once the torque
Publicado em: 2009
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6. Estudo, modelagem e simulação de um inversor de comutação suave para aplicação em filtros ativos de potência monofásicos / A study, modeling and simulation of a soft-switched inverter for an AC single-phase active power filter
This work shows the study, the selection and the analysis of a soft-switched inverter for an ac single-phase active power filter. For this, various topologies of the soft-switched inverters are classified based upon the location of the auxiliary circuit and the topology that achieves the goals for application in the active power filter is selected. Three com
Publicado em: 2007
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7. INTERACTION BETWEEN LOW-RIPPLE SWITCHED CONVERTERS AND FUEL CEL LS / INTERAÇÃO ENTRE CONVERSORES CHAVEADOS COM BAIXA ONDULAÇÃO E CÉLULAS DE COMBUSTÍVEL
This dissertation discusses the interaction between fuel cells and the DC-DC converter just connected across its terminals. For that, it presents a modified algorithm to represent the dynamic behavior of fuel cell stacks as much the current ripple effects from power converters on such cells. PEM type fuel cells (Proton Exchange Membrane) are studied to get a
Publicado em: 2007
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8. O mar azul do Cabo Frio: análise geográfica das atividades ligadas ao mar / The blue waters of Cabo Frio: geographical analysis of the seafaring activies
Looking the importance of the oceans, this work aims to investigate the processes of formation and configuration of the old territory of Cabo Frio, on the coast of Rio de Janeiro, from the presence of the sea, with the factor maritimity as direct or indirect influence on the formation of ancient city of Cabo Frio. We are understanding old Cabo Frio territory
Publicado em: 2007
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9. Redução aluminotérmica do óxido de tântalo usando uma tocha de plasma como ignitor
In this work was used a plasma torch of non transferred arc with argon as work gas, using a power supply with maximum DC current of 250 A and voltage of 30 V to activate the plasma and keep it switched on. The flame temperature was characterized by optical emission spectroscopy, through Boltzmann-plot-method. The torch has been used like igniter in the alumi
Publicado em: 2007
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10. Self-similar LAN/WAN traffic issues on high-speed QoS networks.
During the last decade, the enormous commercial explosion of the Internet has brought up the exhaustive use of Public Telephone Switched Network (PTSN) communication lines by computers (end-users) from all over the world. As a direct consequence of this explosion, a brand new research field, inside the context of the so-called Queuing Theory, has emerged. In
Publicado em: 2004
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11. Electrical current-induced contraction in the smooth muscle of the rabbit aorta.
1. In the smooth muscle of rabbit aorta, the relationship between the change in membrane potential and the concentration evoked by current application was studied. 2. In normal Krebs solution, outward current produced contraction when the membrane was depolarized to about -45 mV and the membrane resistance was decreased. Further increase in the outward curre
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12. Malpractice litigation as a factor in choosing a medical specialty.
Although many factors have been identified as influencing specialty choice, there has been no research focusing on the effects of the current climate of medical practice, including litigation. Our study examines medical students' and residents' awareness of the malpractice litigation environment and their reasons for choosing a specialty that is at either hi