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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

Alterações cromáticas de silicones utilizados na confecção de próteses faciais após envelhecimento / Chromatic alterations in silicons used for facial prosthesis after aging

Cardim, Ricardo Henrique 17 August 2007 (has links)
Através do fato de que os silicones pigmentados utilizados na confecção de aloplastias para a reabilitação de pacientes portadores de defeitos faciais apresentam alteração cromática com o decorrer do tempo na experiência clínica, e pela escassez na literatura específica de trabalhos experimentais relacionados ao tema, principalmente quanto aos silicones industriais de cura acética, o presente trabalho tem como objetivo verificar o comportamento de três tipos de silicones diferentes coloridos com um determinado pigmento (pó para maquiagem facial), usados rotineiramente no atendimento de próteses faciais. Os silicones usados foram um de cura por calor (HTV) para finalidades médicas, um de cura acética (RTV) para fins industriais com especificações de normas alimentícias e outro também de cura acética (RTV), porém somente de normas industriais. Para a realização do experimento confeccionou-se 30 corpos de prova, sendo 10 para cada tipo de silicone, que foram analisados por espectrofotômetro. Após análise, cada grupo foi dividido em 2 subgrupos, de 5 unidades cada, um grupo exposto (E) e um grupo controle (C). Os 3 grupos (E) passaram por envelhecimento acelerado em exposição ambiental, enquanto os 3 grupos (C) ficaram acondicionados em um lugar totalmente escuro em temperatura ambiente. A leitura inicial foi considerada padrão, enquanto as seguintes foram aos 45 e 90 dias. Os dados obtidos nas três medições foram usados para avaliação das alterações cromáticas. Com os resultados estatísticos após análise, concluímos que todos os silicones expostos apresentaram alteração na cor clinicamente inaceitável, sendo que nos grupos controle somente o silicone de cura acética (RTV), industrial com especificações de normas alimentícias, apresentou mudanças cromáticas clinicamente aceitáveis, enquanto os outros dois se mantiveram estáveis. / Owing to the fact that pigmented silicons used in the making of facial prosthesis or the rehabilitation of patients with facial flaws present , in clinical experience, chromatic alteration as time passes by, and due to the shortage of experimental papers in the specific literature, specially in relation to industrial silicon of acetic cure, the present paper targets to verify the behavior of three types of different silicons colored with a determined pigment (facial make up powder), used as routine in facial prosthesis. The used silicons were: one of cure by heat (HTV) with medical purposes , one of acetic cure (RTV) for industrial purposes with specific nutritious rules and another one of acetic cure (RTV) with industrial rules only. To perform the experiment thirty bodies of proof were made , ten to each silicon type, which were analyzed through spectrophotometer. After analyzing, each group was divided into two sub groups, five units each, one group exposed (E) and one group control (C). The three groups (E) passed through accelerated environmental exposure aging, while the three groups (C) stayed in a totally dark place at normal temperature. The initial reading was considered pattern, while the following readings were within 45 and 90 days. The data from the three measurements were used for evaluating the chromatic alterations. With the statistic results at hand, we came to the conclusion that all silicons exposed showed unacceptable clinical color alteration, and in the control groups only the industrial acetic cure silicon (RTV) with specific nutritious rules, showed acceptable clinical chromatic changes while the other two remained stable.
2

Alterações cromáticas de silicones utilizados na confecção de próteses faciais após envelhecimento / Chromatic alterations in silicons used for facial prosthesis after aging

Ricardo Henrique Cardim 17 August 2007 (has links)
Através do fato de que os silicones pigmentados utilizados na confecção de aloplastias para a reabilitação de pacientes portadores de defeitos faciais apresentam alteração cromática com o decorrer do tempo na experiência clínica, e pela escassez na literatura específica de trabalhos experimentais relacionados ao tema, principalmente quanto aos silicones industriais de cura acética, o presente trabalho tem como objetivo verificar o comportamento de três tipos de silicones diferentes coloridos com um determinado pigmento (pó para maquiagem facial), usados rotineiramente no atendimento de próteses faciais. Os silicones usados foram um de cura por calor (HTV) para finalidades médicas, um de cura acética (RTV) para fins industriais com especificações de normas alimentícias e outro também de cura acética (RTV), porém somente de normas industriais. Para a realização do experimento confeccionou-se 30 corpos de prova, sendo 10 para cada tipo de silicone, que foram analisados por espectrofotômetro. Após análise, cada grupo foi dividido em 2 subgrupos, de 5 unidades cada, um grupo exposto (E) e um grupo controle (C). Os 3 grupos (E) passaram por envelhecimento acelerado em exposição ambiental, enquanto os 3 grupos (C) ficaram acondicionados em um lugar totalmente escuro em temperatura ambiente. A leitura inicial foi considerada padrão, enquanto as seguintes foram aos 45 e 90 dias. Os dados obtidos nas três medições foram usados para avaliação das alterações cromáticas. Com os resultados estatísticos após análise, concluímos que todos os silicones expostos apresentaram alteração na cor clinicamente inaceitável, sendo que nos grupos controle somente o silicone de cura acética (RTV), industrial com especificações de normas alimentícias, apresentou mudanças cromáticas clinicamente aceitáveis, enquanto os outros dois se mantiveram estáveis. / Owing to the fact that pigmented silicons used in the making of facial prosthesis or the rehabilitation of patients with facial flaws present , in clinical experience, chromatic alteration as time passes by, and due to the shortage of experimental papers in the specific literature, specially in relation to industrial silicon of acetic cure, the present paper targets to verify the behavior of three types of different silicons colored with a determined pigment (facial make up powder), used as routine in facial prosthesis. The used silicons were: one of cure by heat (HTV) with medical purposes , one of acetic cure (RTV) for industrial purposes with specific nutritious rules and another one of acetic cure (RTV) with industrial rules only. To perform the experiment thirty bodies of proof were made , ten to each silicon type, which were analyzed through spectrophotometer. After analyzing, each group was divided into two sub groups, five units each, one group exposed (E) and one group control (C). The three groups (E) passed through accelerated environmental exposure aging, while the three groups (C) stayed in a totally dark place at normal temperature. The initial reading was considered pattern, while the following readings were within 45 and 90 days. The data from the three measurements were used for evaluating the chromatic alterations. With the statistic results at hand, we came to the conclusion that all silicons exposed showed unacceptable clinical color alteration, and in the control groups only the industrial acetic cure silicon (RTV) with specific nutritious rules, showed acceptable clinical chromatic changes while the other two remained stable.
3

Strukturelle Klebungen mit UV- und lichthärtenden Acrylaten

Vogt, Iris 30 March 2009 (has links)
UV- und lichthärtenden Acrylatklebstoffen steht ein breites Anwendungsspektrum im Konstruktiven Glasbau offen. Ihr farbloses und klares Erscheinungsbild fördert eine Konstruktion, die transparent und leicht wirken soll. Kurze Aushärtezeiten, die sich im Sekunden- oder einstelligen Minutenbereich bewegen, ermöglichen eine schnelle Herstellung und reduzieren die Lagerzeiten. Die geklebten Konstruktionen können direkt weiterverarbeitet werden. Durch diese Vorteile heben sie sich von den Silikonklebstoffen ab, die für ausge-wählte Anwendungen im Fassadenbau (Structural-Sealant-Glazing-Systems - SSGS) bauaufsichtlich zugelassen sind. Gegenstand dieser Arbeit ist die Aufstellung von Empfehlungen zur Planung und Berechnung struktureller Klebungen mit strahlungshärtenden Acrylaten. Dafür werden Klebstoffe an dem reinen Material sowie in Verbindungen mit Glas und Metall untersucht. Für ein umfangreiches Bild über das Verhalten des Materials bieten sich Substanzprüfkörper an, die mit überschaubarem Aufwand eine Auswertung verschiedener Einflüsse - beispielsweise Temperatur und Prüfgeschwindigkeit - erlauben. An in-situ-Prüfkörpern kann der Klebstoff in der Verbindung betrachtet werden. Durch Wechselwirkungen zwischen Klebstoff und Fügeteil bildet sich eine sogenannte Grenzschicht aus, die gradierte Eigenschaften besitzt und die Materialkennwerte - besonders bei dünnen Klebfugen - beeinflusst. Weiterhin erlauben diese Prüfkörper eine Aussage über das Tragverhalten der Klebverbindung. Um das Potenzial der Acrylatklebungen in der Glasarchitektur aufzuzeigen und in der Anwendung zu prüfen, werden Bauteile mit punktförmig geklebten Halterungen untersucht. Absturzsicherungen werden statischen und dynamischen Belastungen unterworfen. An Überkopfverglasungen werden Trag- und Resttragfähigkeitsuntersuchungen durchgeführt. Bauteile im Freien geben Aufschluss über das Alterungsverhalten unter natürlichen klimatischen Bedingungen. / UV and light curing acrylates present a whole host of possibilities for the implementation of glass construction. Their clear and colourless appearance produces a transparent and lightweight construction. Short curing times consisting of no more than mere minutes allow for quick production with minimal downtime within the overall process. Processing can be resumed immediately once bonding has occurred. The advantages of acrylates can be compared to the characteristics and properties of adhesive silicones which have been widely approved by building authorities for specific façade applications (Structural-Sealant-Glazing-Systems - SSGS). The subject matter of this study is the development of auxiliary tools to plan and design adhesively bonded joints of UV and light curing acrylates. These adhesives are, therefore, analysed both generally as bulk material and in applications as a joint between glass and metal. The use of dog bone shaped specimens is recommended to analyze the material behaviour under a variety of influence factors such as temperature and testing rate. The bonded joints of test specimens provide an opportunity to examine the interaction between the adhesive and the materials to which they are adhered. An interface with graded properties is formed based upon the interactions between adhesive joints and each particular substrate. Further on, bonded specimens enable the development of a statement concerning the load-bearing capacity of joints. Constructions having spot bonded joints are tested to demonstrate the potential use of acrylic joints in architectural glass treatments. Safety barriers are tested under both static and dynamic loads. Sloped roof systems are tested to substantiate load-bearing capacity and to verify any residual carrying capacity. Components are exposed to natural weathering in order to examine the affects of ageing on the adhesive.

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