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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.
31

Avaliação das emissões conduzidas e radiadas geradas por unidade eletrocirúrgica e sistema de iluminação com lâmpadas fluorescentes em equipamentos médicos

Moraes, Fábio Brignol de 16 December 2013 (has links)
Este trabalho apresenta um estudo sobre interferência eletromagnética, emissões radiada e conduzida, gerados pelo sistema de iluminação e pela unidade de eletrocirurgia (bisturi eletrônico) numa sala cirúrgica de um hospital da cidade de Pato Branco/PR. O trabalho consistiu em medidas de emissões conduzidas e radiadas de sistemas de iluminação fluorescentes em laboratório e de emissões conduzidas e radiadas “in loco” da unidade de eletrocirurgia. Além disso, foi feito estudo de referenciais sobre as normas, nacionais e internacionais, que incidem sobre estes dois sistemas. Como resultado do trabalho tem-se um panorama sobre a situação das emissões conduzidas e radiadas, pelos sistemas de iluminação fluorescente e unidade eletrocirúrgica utilizados no hospital. / This work presents a study on electromagnetic interference radiated and conducted emissions generated by the lighting system and the electrosurgery unit (eletric scalpel) in na operating room of a hospital in Pato Branco / PR. The work consisted of measurements of conducted and radiated emission of fluorescent lighting systems in the laboratory of conducted and radiated “in loco” electrosurgery unit emissions. Futhermore, a study was made of references on standarts, national and international, that focus on these two systems. Because of the work, has an overview on the situation of conducted and radiated emissions, the fluorecent lighting used in electrosurgical unit and hospital systems.
32

Sistema eletrônico para lâmpadas fluorescentes de indução baseado na topologia sepic half-bridge bi-integrada com controle de intensidade luminosa por modulação de baixa frequência / Electronic system for induction fluorescent lamps based on bi-integrated sepic half-bridge topology with low frequency modulation dimming control

Fraytag, Jeferson 15 June 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis presents the analysis and design of an electronic drive system for fluorescent induction lamps. This lighting technology, despite being patented since the 60s, is not widely diffused in the market context. However, it is an extremely attractive alternative due to long lifetime and high luminous efficiency. The analysis circuit consists of a power factor correction associated with a power control stage, which provides the lamp ignition and current limitation. An integration methodology is applied in order to reduce the number of active semiconductor switches. The resulting topology, called here SEPIC half-bridge, presents a shared switch able to act, both in the pre-regulator stage, as well as for the power control stage. The number of elements reduction also occurs by magnetic integration. In this case, the pre-regulator inductors are distributed in a single core. For electronic system flexibility, it was inserted the dimming capability, where the low frequency modulation technique was evaluated. This technique is suitable for high power variation rates and provides a stable operation. The topology is controlled by a feedback system ensuring a satisfactory response of the system when subjected to disturbances, in addition to ensuring the correct power to the lamp. The electronic ballast designed behavior was evaluated experimentally. In this situation, there was obtained a low input current distortion associated with a high power factor. The lamp power variation range was 70% (30 W to 100 W), with an average efficiency around 82%. / Neste trabalho de mestrado, apresenta-se a análise e o projeto de um sistema eletrônico de acionamento para lâmpadas fluorescentes de indução. Esta tecnologia de iluminação, apesar de ser patenteada desde a década de 60, ainda é pouco difundida em âmbito comercial. Entretanto, é uma alternativa extremamente atraente devido a longa vida útil e a elevada eficiência luminosa. O circuito analisado consiste de um estágio de pré-regulação do fator de potência associado a um estágio de controle de potência, capaz de prover as necessidades de partida e limitar a corrente aplicada à lâmpada. Para estes estágios, visando a redução do número de semicondutores ativos, é aplicada a metodologia de integração de interruptores. A topologia resultante, chamada de SEPIC half-bridge, apresenta um interruptor compartilhado, capaz de atuar tanto para o pré-regulador, quanto para o controle de potência. A redução do número de elementos se dá também pela integração de magnéticos. Nesta situação, os indutores do pré-regulador são distribuídos em um único núcleo. Buscando a flexibilidade do sistema eletrônico, neste foi inserido a capacidade de variação da intensidade luminosa, onde a técnica de modulação de baixa frequência foi avaliada. Tal técnica é apropriada para elevados índices de variação de potência, além de proporcionar uma operação estável do circuito. A topologia é controlada por um sistema de retroalimentação, capaz de garantir uma resposta satisfatória do sistema quando submetido a distúrbios, além de garantir a potência processada pela lâmpada. O comportamento do reator eletrônico projetado foi avaliado experimentalmente. Nesta situação, obteve-se uma baixa distorção da corrente de entrada e elevado fator de potência. A faixa de variação de potência foi de 70% (100 W à 30 W), com um rendimento médio de 82%.
33

Změna parametrů výbojových světelných zdrojů s frekvencí napájecího proudu / Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources

Kuptsov, Alexander January 2014 (has links)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting laboratory experiments the influence of frequency of the supply current on different properties of gas-discharge lamps was described. Besides, simulation of basic electric parameters of high-pressure gas-discharged lamps was implemented in the program SIMULINK/MATLAB. As a result, the received graphs show the dependence of current, voltage and electric power on time. Another simulation included building of dynamic current-voltage characteristics at various frequencies of the supply current. Preparations for the laboratory experiment and the experiment itself were implemented. Compact and tube low-pressure fluorescent lamps were measured. The received graphs show the influence of change in frequency of the current on the operational parameters of the discharge light sources.
34

Lehčené omítky modifikovaného složení pro konečnou povrchovou úpravu ETICS / Lightweight plasters of modified composition for final surface treatment of ETICS

Neubauerová, Alena January 2014 (has links)
The diploma thesis is focused on the verification of the parameters of thin lightweight mineral plasters with modified composition. As alternative raw materials are used expanded perlite Vapex, calcined diatomite Celite and powder waste glass of fluorescent lamps. In the theoretical part is summarized knowledge from completed studies dealing with the issue of compensation porous filler component. In the experimental part is tested consistency of fresh mixture, physical-mechanical, sorption and thermal insulating characteristics. It is compared the appearance of the surface and summarized the results of measuring.

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