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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.
11

Sistema termoelétrico aplicado ao estudo dos efeitos de congelamento e de propriedades térmicas / Thermoelectric system applied to study effects of freezing and thermal properties

Silva, Karla, 1971 21 August 2018 (has links)
Orientador: Vivaldo Silveira Júnior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T13:26:25Z (GMT). No. of bitstreams: 1 Silva_Karla_D.pdf: 5033012 bytes, checksum: 65b836ec14627b88ae3c341f00426fab (MD5) Previous issue date: 2012 / Resumo: Módulos termoelétricos ou Peltier podem funcionar como bombas de calor promovendo o fluxo térmico entre suas faces opostas à custa da inserção de potência elétrica. O efeito Peltier profere a linearidade entre transferência de calor e corrente elétrica inserida, tornando o módulo um aparato de características potencialmente ideais aos estudos dos efeitos das trocas térmicas. Nesse contexto, o presente trabalho traz o projeto, montagem e avaliação de um protótipo termoelétrico idealizado para congelamento unidirecional por contato direto de amostras consistentes em placa Peltier. A instrumentação do sistema possibilitou o monitoramento da potência elétrica inserida na placa e das temperaturas em diferentes pontos da superfície da placa bem como do espaço interno do sistema. Os testes de avaliação do protótipo comprovaram a adequada montagem com garantia das leituras dos sensores, bem como a boa repetibilidade dos resultados em nível de significância de 5%. Os resultados obtidos para congelamentos de gel de gelatina 2% confirmaram a viabilidade de uso do aparato para estudos dos efeitos de diferentes taxas de congelamento sobre a estruturação do gelo, com alto nível de monitoramento das condições de avanço da frente de congelamento. A precisão do protótipo em detectar pontos de alterações energéticas na amostra, nas proximidades de pontos de alterações estruturais, inferiu na utilização do aparato para estudos térmicos de materiais. Assim, o protótipo termoelétrico foi testado como ferramenta de estudos térmicos, evidenciando-se a possibilidade de seu uso para determinação da região de transição vítrea. A utilização desse aparato para análises térmicas viabiliza e torna mais eficiente o processo comparativamente aos métodos tradicionalmente empregados como o DSC / Abstract: Peltier modules or thermoelectric modules can operate as a heat pump promoting the heat flow in its opposite faces from inserting electric power. The Peltier effect gives the linearity between heat transfer and inserted electrical current, making the characteristics of an apparatus module potentially ideal for studies of the effects of heat exchange. In this context, this paper presents the design, assembly and evaluation of a thermoelectric prototype designed for unidirectional freezing of samples by direct contact semi-solid thermal plate. The instrumentation system allowed the monitoring of electrical power inserted into the card and temperatures in different parts of the plaque and the internal space of the system. The evaluation tests of the prototype proved to guarantee proper assembly of the sensor readings, as well as the good repeatability of results at a 5% significance level. The results for freezing of gelatin gel 2% confirmed the feasibility of using the apparatus for studies of the effects of different freezing rates on the structure of ice, with a high level of conditions monitoring the advancing of the cold freezing. The high accuracy of the prototype in detecting points of energy in the sample, inferred changes in the use of apparatus for thermal study of materials, so the thermoelectric prototype was tested as a tool for thermal studies, demonstrating the possibility of its use for determining the region vitreous transition. The use of this Peltier modules enable it to be more efficient compared to traditional processes such as DSC / Doutorado / Engenharia de Alimentos / Doutora em Engenharia de Alimentos
12

The effect of aging and heat treatment on the stability of the chromel-constantan thermocouple

Michaelides, George J. January 1954 (has links)
no abstract provided by author / Master of Science
13

Termal elektrik kaynaklı kablosuz yüksek sıcaklık duyum devresi /

Aruğaslan, Emine. Küçükkömürler, Ahmet. January 2008 (has links) (PDF)
Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik-Bilgisayar Eğitimi Anabilim Dalı, 2008. / Kaynakça var.
14

The determination of pulp vitality by the use of thermal and electric stimuli thesis submitted in partial fulfillment ... oral diagnosis ... /

Reynolds, Richard L., January 1965 (has links)
Thesis (M.S.)--University of Michigan, 1965.
15

The determination of pulp vitality by the use of thermal and electric stimuli thesis submitted in partial fulfillment ... oral diagnosis ... /

Reynolds, Richard L., January 1965 (has links)
Thesis (M.S.)--University of Michigan, 1965.
16

The thermoelectrostatic energy converter

Vliet, Daniel Hendricks, January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. Description based on print version record. Includes bibliographical references.
17

Thermoelectric cooling for microwave transmitters located at remote sites

Pietersen, Richard Gordon January 1992 (has links)
Thesis (MDiploma (Mechanical Engineering))--Cape Technikon, 1992. / An investigation into the use of thermoelectric cooling energised by photovoltaic (PV) panels for removing sensible heat from electronic telecommunications equipment. The thermoelectric cooler consists of a solid-state heat pump which operates on the principle of the Peltier effect. The thermoelectric device transfers heat through a cold sink to ambient outside air via a hot sink. A major prerequisite was that the system should be selfsufficient in terms of power because the sites for the microwave transmitters are often remote. Solar power was the only alternative source of energy and the cooler was designed to accept direct current from PV panels which are usually used to power transmitters on distant locations. The cooling device had to be reliable, virtually maintenance-free and simple to repair.

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