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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.
1

Estudo da decomposição térmica de ácidos graxos através da calorimetria exploratória diferencial / Study of thermal decomposition of fatty acids through differential scanning calorimetry

Matos, Flávio Cardoso de, 1983- 02 June 2012 (has links)
Orientador: Maria Alvina Krähenbühl / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-20T01:57:06Z (GMT). No. of bitstreams: 1 Matos_FlavioCardosode_M.pdf: 4389561 bytes, checksum: a46da733dd13422f2fad87695175b3db (MD5) Previous issue date: 2012 / Resumo: Neste trabalho foi estudado o efeito do aquecimento, à pressão constante, de ácidos graxos, desde a fusão até a sua decomposição térmica, para delimitação das temperaturas de fusão, ebulição e decomposição. A Calorimetria Exploratória Diferencial, técnica na qual a medida da taxa de fluxo de calor para uma amostra é descrita em função da temperatura ou tempo, foi utilizada para realização de um estudo térmico dos ácidos graxos, ácido cáprico (C 10:0), láurico (C 12:0), mirístico (C 14:0), pentadecanóico (C 15:0), palmítico (C 16:0), esteárico (C 18:0), oleico (C 18:1), linoléico (C 18:2) e araquídico (C 20:0), nas taxas de aquecimento de 5, 10, 15 e 20 ºC.min-1. A temperatura de onset, temperatura de pico e a entalpia foram calculadas de acordo com as curvas térmicas para os eventos endotérmico e exotérmico. Os resultados experimentais foram comparados com dados reportados na literatura, quando disponíveis. Os resultados obtidos mostraram-se satisfatórios, quando comparados com dados de outros autores / Abstract: In this work it was studied the effect of heating, at constant pressure, of fatty acids, from the melting until their thermal decomposition, for delimitation of the temperatures of melting, boiling and decomposition. Differential Scanning Calorimetry, the measurement technique in which the rate of heat flow for a sample is described as a function of temperature or time, was used to conduct a thermal study of fatty acids: capric acid (C 10:0), lauric (C 12:0), myristic (C 14:0), pentadecanoic (C 15:0) palmitic (C 16:0), stearic (C 18:0), oleic (C 18:1), linoleic (C 18:2) and arachidic (C 20:0), at the heating rates of 5, 10, 15 and 20 ° C / min. The onset temperature, peak temperature and enthalpy were calculated according to the thermal curves for the exothermic and endothermic events. The experimental results were compared with data reported in the literature when available. The results were satisfactory when compared with data from other authors / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
2

Analýza složení močových konkrementů pomocí výpočetní tomografie s duální energií záření / Composition analysis of urinary calculi with dual-energy computed tomography

Vondráková, Alena January 2015 (has links)
Composition analysis of urinary calculi with dual-energy computed tomography Urolithiasis is among lifestyle diseases. Question the timely and accurate diagnosis is still current. Therapeutic approach in dealing with kidney stones depends on the particular chemical composition of urinary stone. Since the end of the 20th century as a new diagnostic option in the problems of urolithiasis exploring the possibility of using techniques of DECT, which now brings the possibility of the material characteristics of tissues in vivo. The aim of the present study was to assess the accuracy of chemical analysis stone disease DECT correlation of the results with laboratory chemical analysis of urolithiasis. The research sample of patients with urolithiasis became of the 70 individuals who underwent examination using DECT focusing on the chemical analysis of urinary calculi in vivo. Subsequently, analysis was made of laboratory extracted urolithiasis in all these patients. With regard to the distribution of urolithiasis into 4 main types according to the chemical composition of the stone was then assessed compliance DECT and laboratory methods. Consensus of both analytical methods were investigated on a small set of blind investigated calculi of known chemical composition ex vivo. The main outcome of this work is...

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