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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

Subcoberturas: aplicação de isolantes térmicos em sistemas de coberturas / not available

Carletto, Consuelo 20 May 2005 (has links)
Este trabalho tem como foco principal apresentar os resultados e as contribuições da pesquisa experimental comparativa de subcoberturas em sistemas de cobertura. Para tal fim foram utilizados quatro protótipos localizados no canteiro experimental do CRHEA - EESC em São Carlos, São Paulo. Os protótipos foram construídos da mesma forma e com os mesmos materiais: tijolo comum, laje cerâmica recapeada com concreto; cobertos com telhas de fibrocimento e submetidos às mesmas excitações de clima ao ar livre. A análise foi feita aplicando um curto intervalo de clima, com respaldo teórico da climatologia dinâmica. Um dos protótipos serviu como testemunho e não recebeu a instalação de nenhuma subcobertura. Os outros três receberam cada um, respectivamente, subcobertura de foil (isolante por reflexão, ou barreira de radiação), lã de rocha (isolante convencional, condutividade térmica k) e de caixas cartonadas Tetra Pak, um resíduo, como isolante por reflexão e câmara de ar, já que foram utilizadas fechadas e uma ao lado da outra. Foram monitoradas as temperaturas superficiais da telha e da laje e, das temperaturas de bulbo seco no ático e na parte interna dos protótipos a 1,10 m de altura. As medidas de aquisições de dados foram feitas através de CR10X Campbell Scientific automático com medições em 30 segundos, armazenados e totalizados em 30 minutos, o que resultou em valores de clima ao livre e em recinto fechado muito precisos. / Thermal comfort achievement can be done by using thermal reflexive barriers, meaning energy savings and avoiding health problems of air conditioning. It can also be done by using building construction waste materials as Tetra Pak boxes, a low cost reflexive insulation, and applying an industrial \"foil\" which the same effect on reducing indoor air temperatures. In the same way traditional thermal insulation materials were used on this research as the mineral wool (conventional insulation material, thermal conductivity - k values). The analysis was made applying short intervals of climate such as recommended by the dynamic climatic approach. The use of foil insulation can be justified because of its behavior as a reflective barrier and because it has a lot of acceptation; mineral wool (mineral source with low k insulation values) for being a traditional kind of thermal insulation and the Tetra Pak box, because it is a reflective insulation and also because of its waste recycle usage characteristic. The research shows the insulation thermal efficiency applied on three kinds of fiber asbestos cover system, which makes the indoor air temperatures inside of comfort zones values, as intended to expose by graphics, made by real time and automatic experimental measurements. The measurements of data acquisitions were made by automatic CR10X Campbell Scientific Inc., 30 seconds scanner and totalized storage as 30 minutes average intervals. This means a very accurate result of values of outdoor and indoor climate translated by indoor and out door air temperatures.
2

Subcoberturas: aplicação de isolantes térmicos em sistemas de coberturas / not available

Consuelo Carletto 20 May 2005 (has links)
Este trabalho tem como foco principal apresentar os resultados e as contribuições da pesquisa experimental comparativa de subcoberturas em sistemas de cobertura. Para tal fim foram utilizados quatro protótipos localizados no canteiro experimental do CRHEA - EESC em São Carlos, São Paulo. Os protótipos foram construídos da mesma forma e com os mesmos materiais: tijolo comum, laje cerâmica recapeada com concreto; cobertos com telhas de fibrocimento e submetidos às mesmas excitações de clima ao ar livre. A análise foi feita aplicando um curto intervalo de clima, com respaldo teórico da climatologia dinâmica. Um dos protótipos serviu como testemunho e não recebeu a instalação de nenhuma subcobertura. Os outros três receberam cada um, respectivamente, subcobertura de foil (isolante por reflexão, ou barreira de radiação), lã de rocha (isolante convencional, condutividade térmica k) e de caixas cartonadas Tetra Pak, um resíduo, como isolante por reflexão e câmara de ar, já que foram utilizadas fechadas e uma ao lado da outra. Foram monitoradas as temperaturas superficiais da telha e da laje e, das temperaturas de bulbo seco no ático e na parte interna dos protótipos a 1,10 m de altura. As medidas de aquisições de dados foram feitas através de CR10X Campbell Scientific automático com medições em 30 segundos, armazenados e totalizados em 30 minutos, o que resultou em valores de clima ao livre e em recinto fechado muito precisos. / Thermal comfort achievement can be done by using thermal reflexive barriers, meaning energy savings and avoiding health problems of air conditioning. It can also be done by using building construction waste materials as Tetra Pak boxes, a low cost reflexive insulation, and applying an industrial \"foil\" which the same effect on reducing indoor air temperatures. In the same way traditional thermal insulation materials were used on this research as the mineral wool (conventional insulation material, thermal conductivity - k values). The analysis was made applying short intervals of climate such as recommended by the dynamic climatic approach. The use of foil insulation can be justified because of its behavior as a reflective barrier and because it has a lot of acceptation; mineral wool (mineral source with low k insulation values) for being a traditional kind of thermal insulation and the Tetra Pak box, because it is a reflective insulation and also because of its waste recycle usage characteristic. The research shows the insulation thermal efficiency applied on three kinds of fiber asbestos cover system, which makes the indoor air temperatures inside of comfort zones values, as intended to expose by graphics, made by real time and automatic experimental measurements. The measurements of data acquisitions were made by automatic CR10X Campbell Scientific Inc., 30 seconds scanner and totalized storage as 30 minutes average intervals. This means a very accurate result of values of outdoor and indoor climate translated by indoor and out door air temperatures.
3

Desempenho termico da espuma poliuretana a base de oleo de mamona utilizada em componentes da edificação (subcoberturas) : estudo em Ilha Solteira, SP / Thermal performance of a castor oil foam as insulating material inside the roof : study case in the city of Ilha Solteira, Brazil

Lopes, Edmar Maria Lima 05 April 2009 (has links)
Orientador: Lucila Chebel Labaki / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-14T03:28:06Z (GMT). No. of bitstreams: 1 Lopes_EdmarMariaLima.pdf: 8612445 bytes, checksum: 69659b28ac6e14c5f71ca12f206444ac (MD5) Previous issue date: 2009 / Resumo: O óleo de mamona após seu processamento e síntese, dá origem a uma poliuretana, termicamente compatível com as poliuretanas de origem petroquímica, mas com toxidade quase nula e baixa flamabilidade. A utilização da espuma de mamona é ecologicamente correta por tratar-se de uma fonte vegetal renovável, não tóxica durante o seu manuseio Através da experimentação de 4 (quatro) células-teste em escala 1: 1 foram utilizadas placas de espuma poliuretana de mamona, como isolante térmico em coberturas. A diferença entre as células-teste apresenta-se na localização das placas de resina poliuretana. Na quarta célula-teste (casa 4), está localizada a central de tomada dos dados. Na primeira (casa 1), a espuma poliuretana encontra-se em forma "sandwich", localizada entre as telhas de fibrocimento. A segunda (casa 2), não possui nenhum tipo de isolamento térmico - é a célula-teste utilizada como referência para este estudo e na terceira (casa 3), a espuma poliuretana é colocada diretamente sobre a laje. O trabalho teve como objetivo verificar comparativamente, a resposta térmica das coberturas utilizando a espuma poliuretana de mamona como isolante térmico na cobertura, englobando duas estações climáticas, final do verão e o inverno. Em diferentes períodos da pesquisa utilizou-se as telhas de fibrocimento em sua cor natural e com a telha pintada na cor branca. Foram registradas as temperaturas de bulbo seco, bulbo úmido e de globo internas e externas do ar e as temperaturas superficiais dos elementos construtivos componentes da cobertura. A análise dos dados foi feita comparando-se as temperaturas de cada uma das células - teste, com as temperaturas externas, tomadas por uma pequena estação meteorológica. O experimento foi desenvolvido na cidade de Ilha Solteira/SP, região noroeste do estado A célula-teste 1 (casa 1), que possui o isolante térmico em forma "sandwich " entre as telhas e com as telhas pintadas na cor branca, apresentou melhor desempenho térmico, para utilização no inverno-seco e, a célula-teste 3 (casa 3), com o isolante diretamente sobre a laje e com as telhas pintadas de branco, demonstrou melhor comportamento térmico no verão quente-úmido. / Abstract: The aim of this work is to describe an experimental study using castor oil foam as an insulating material inside the roof. The castor oil foam inside the roof is an appropriate natural recycled material as a passive cooling strategy as opposite to the burning of fossil fuels for air conditioning (AC) and mechanical ventilation. The expected result of this research is the possibility of contributing to improve thermal comfort and quality of life in the built environment. This experimental study is based on collecting data under real climate conditions of temperature and humidity to investigated the thermal performance in four test-cells with castor oil foam inside their roofs, in the city of Ilha Solteira located at northwest region of São Paulo State, in Brazil. In this research four test-cells constructions were used for data collection of ambient and surfaces temperatures with dimensions 3,00 x 2,00 x 2,50 m in real scale. The first test-cell was composed with insulating material like a sandwich. The second one with no insulating material was taken by reference. The third one was had insulating material on the flag and on the fourth was found the central of data collection. This work compared about the behavior in the test-cells applying castor oil foam on four different periods of the year: two on the summer and two in the winter. Results showed up the best thermal performance on the summer period was demonstrated on the test-cell no 3, presenting white roofing. Otherwise in the winter, the best thermal behavior was presented on the test cell no 1, with white roofing, too. / Universidade Estadual de Campi / Arquitetura e Construção / Doutor em Engenharia Civil
4

Optimisation et analyses des propriétés physico-chimiques et diélectriques du parylène D / Optimisation and analysis of physico-chemical and dielectriques properties of parylene D

Mokni, Marwa 17 December 2016 (has links)
Ce travail est consacré à l’élaboration et à la caractérisation de couches minces de parylène D déposées par dépôt chimique en phase vapeur (CVD) sous forme de films de quelques microns d’épaisseur. L’objectif de l’étude est d’évaluer les potentialités de ce polymère en remplacement des parylènes de type N ou C pour des applications spécifiques ou encore pour l’intégrer dans de nouvelles applications. Une première étude a consisté à évaluer l’impact des paramètres des dépôts CVD (température de sublimation, température de pyrolyse, température du substrat d’accueil du film déposé) sur les changements physico-chimiques, structuraux et diélectriques du parylène D. Pour cela, nous nous sommes appuyés sur des analyses FTIR, XRD, DSC, TGA, AFM, SEM, DMA. Nous avons également appliqué des stress thermiques au parylène D dans le but d’évaluer leur performance à haute température (>200°C) ainsi que les changements opérés au niveau de la structure cristalline (taille des cristallites, pourcentage de cristallinité,…) ou encore la stabilité des propriétés thermiques (température de transition vitreuse, température de cristallisation, température de fusion) et diélectriques (constante diélectrique e’, facteur de dissipation tand et conductivité basse fréquence s’) Enfin, des analyses diélectriques en fréquence (de 0,1Hz à 100 kHz) sur une large plage de température de fonctionnement (-140°C – 350°C) ont permis de mettre en évidence la présence de trois mécanismes de relaxations (a, b, g), une polarisation d’interface de type Maxwell-Wagner-Sillars et une polarisation d’électrode. Les performances diélectriques sont également discutées par comparaison aux parylènes de type N et C plus couramment utilisés aujourd’hui dans les applications industrielles. Cette étude permet ainsi de disposer maintenant de paramètres de dépôt CVD bien contrôlés pour le dépôt de films de parylènes D aux propriétés souhaitées pour une application spécifique / This work is mainly focused on the elaboration and the characterization of parylene D thin films of few micrometers deposited by chemical vapor deposition (CVD). The goal of this study is to evaluate the potentialities of this polymer in order to replace the parylene N or C for specific applications or to integrate it in new applications. A first study consisted in evaluating the impact of the CVD process parameters (temperature of sublimation, temperature of pyrolysis, substrate temperature) on the surface morphology, the molecular structure and dielectric changes of parylene D. For that, we were based on several analyzes techniques as FTIR, XRD, DSC, TGA, AFM, SEM, DMA. Thermal stresses were applied to parylene D to evaluate their performance at high temperature (>200°C) and the changes on the crystal structure (size of crystallites, percentage of crystallinity,…) or the stability of the thermal properties (temperature of transition, temperature of crystallization, melting point) and dielectric properties (the dielectric permittivity, the dissipation factor, the electrical conductivity and the electric modulus). Dielectric and electrical properties of Parylene D were investigated by dielectric spectroscopy in a wide temperature ranges from -140°C to 350°C and frequency from 0.1 Hz to 1 MHz, respectively. (a, b and g)-relaxation mechanisms, interfacial polarization related to Maxwell-Wagner-Sillars and electrode polarization have been identified in this polymers. The dielectric performances of Parylene D have been also compared with parylenes N and C which are used in wide industrial applications. Optimized and controlled conditions of the CVD process of parylenes D are proposed in this work in relation to the properties. The obtained results open a new way for specific applications.
5

Vliv plnění na dielektrické vlastnosti elektroizolačních laků / Influence of Filling on Dielctric Properties of Electroinsulation Varnish

Kisiala, Ondřej January 2008 (has links)
This work deals with issues of elecroinsulating varnish and composite materials. The general aim is to observe impact of fulfilment and size of particle against measured values.
6

Vliv plnění nanočásticemi na dielektrické vlastnosti elektroizolačních laků / Influence of nanoparticles on the properties of electroinsulation varnish

Michlíček, Petr January 2009 (has links)
This work deals with issues of dielectric composite materials. The general aim is to observe how the amout of nanofilling influence dielectric spectrum in dependence on relative humidity and temperature which is measured on prepared samples. For this purpose had been created variety of a samples of electroinsulating varnish with different percentage of filling with nanoparticles. Experimental material is epoxy resin NH91 LV filled by Al2O3 nanoparticles.
7

Studium elektrických vlastností kompozitních materiálů / Study of electric properties of composite

Macháček, Miroslav January 2009 (has links)
This work deals with issues of composite materials. The general aim is to observe how the amout of filling infuence dielectric spectrum which is measured on prepared samples. For this purpose had been created variety of a samples with different percentage of filling with mica. Measured values had been compared with theoretically values, determinated using mixture formulas.
8

Caractérisation thermique et mécanique de fibres naturelles d'origine marine en vue de leur utilisation dans les matériaux de l'habitat / Thermal and mechanical characterization of natural marine fibers intended to be used as construction materials

Hamdaoui, Ons 12 December 2018 (has links)
Dans ce travail de thèse, nous proposons dans une première partie l’usage de fibres de la plante marine Posidonia-Oceanica pour la fabrication de matériaux d’isolation thermique de bâtiments. Les caractérisations thermiques effectuées ont permis de mettre en évidence l’effet de la densité des fibres et de traitements chimiques. Il apparaît que ce type de fibres possède une conductivité équivalente à celle d’autres isolants courants et une capacité thermique massique plus élevée. La conductivité thermique en fonction de la masse volumique est comprise entre 0.04 et 0.07 W.m-1.K-1. La capacité thermique massique atteint environ 2500J.kg-1.K-1. Il apparaît également que l’influence du traitement chimique sur les propriétés thermiques n’est pas significative. Les résultats obtenus font de ces fibres un bon candidat pour une utilisation comme isolant thermique dans le domaine du bâtiment. Dans une seconde partie, ces fibres sont utilisées pour le renforcement d’une pâte de ciment. Une gamme de composites a été formulée pour des fractions volumiques en fibres allant de 0 à 20%. Une étude des propriétés hydriques de ces composites a été menée et complétée par des analyses par spectroscopie infrarouge à transformée de Fourier (FTIR) et des mesures des propriétés thermophysiques par la méthode du Hot-Disk durant le cycle de séchage. D’autre part, la quantification de la sensibilité de ces matériaux à l’humidité relative a été réalisée par la mesure de la variation de la teneur en eau dans les échantillons dans des environnements à humidité contrôlée. Ces mesures permettent de déterminer le coefficient de diffusion de l’eau. Celui-ci augmente légèrement avec l’augmentation du taux de fibres dans le composite. Du point de vue thermique, l’ajout de fibres améliore les propriétés isolantes des matériaux. En effet, une diminution de 22% sur la valeur de la conductivité thermique est notée avec l’introduction de 20% de fibres, par comparaison à l’échantillon de ciment témoin. L’influence sur la diffusivité thermique et sur la capacité thermique massique n’est pas significative. Du point de vue mécanique, la résistance à la traction par flexion et la compression augmentent légèrement jusqu’à 5 à 10% en volume de fibres puis diminuent. En revanche, une augmentation notable des valeurs de ténacité a été observée avec l’augmentation du dosage en fibres. Une augmentation de 65% est observée avec l’ajout de 20% de fibres. En s'appuyant sur les observations expérimentales, une modélisation analytique simplifiée a été réalisée. Celle-ci permet d'obtenir des modèles de prédiction des valeurs de la conductivité thermique, de la résistance à la traction par flexion, de la résistance à la compression et de la ténacité en fonction de la quantité de fibres dans le matériau / In this work, we have firstly studied the use of fibers extracted from the marine plant Posidonia-Oceanica as loose-fill thermal insulation material for buildings. Measurements were conducted and allowed the determination of the effect of fibers density and chemical treatments on thermal properties. Thermal conductivities were lying between 0.04 and 0.07 W.m-1.K-1, whereas the heat capacity is about 2500 J.kg-1.K-1. Thus, it was found that fibers thermal conductivity is close to the one of commonly used thermal insulation materials and that their heat capacity is significantly higher. It was also found that the influence of chemical treatment on the thermal properties is not significant. Measurement results showed that these fibers could be a promising ecological loose-fill insulation material in the construction field. Secondly, fibers were used as reinforcement for cement paste. A set of composite samples were formulated by varying fibers volume fractions from 0 to 20%. Their hygroscopic, thermal and mechanical properties were evaluated. Composites were analyzed by Fourier transform infrared spectroscopy (FTIR) and their thermophysical properties were measured with a Hot Disk thermal constants analyzer during the drying cycle. Sensitivity of these materials to relative humidity was examined by measuring the water content variation in controlled humidity environments. These measurements allowed the quantification of the water diffusion coefficient. This coefficient increased slightly with the increase of fibers content in composite samples. Concerning thermal properties, the addition of Posidonia-Oceanica fibers improved the material insulating properties. In fact, a decrease of about 22% on thermal conductivity values was found with the introduction of 20% of fibers compared to the unfilled cement paste. For Posidonia-Oceanica fibers volume fractions considered in this study (0 to 20 Vol.%), the effect of the presence of fibers on thermal diffusivity and on heat capacity is not significant, regarding the measurement uncertainties. Concerning mechanical properties, flexural and compressive strengths increased for about fiber volume fractions in the range of 5 to 10%. Moreover, a noticeable increase of toughness was observed with increasing fibers amount: for instance, an increase of about 65% was observed with the introduction of 20% of fibers in the composite. Based on the experimental observations, simplified analytical models were developed to predict thermal conductivity, flexural strength, compressive strength and toughness as a function of fibers volume fraction in the material
9

Thermal Conductivity Enhancement Of Polymer Based Materials

Kashfipour, Marjan Alsadat 29 August 2019 (has links)
No description available.
10

Comportement thermo-hygrique de blankets aérogels de silice et applications à l’isolation des bâtiments / Thermo-hygric behavior of silica aerogel blankets and applications to building insulation

Nocentini, Kévin 14 December 2018 (has links)
En Europe, le secteur du bâtiment est le plus énergivore et représente environ 40 % de l’énergie totale consommée. A court terme, la façon la plus efficace de baisser cette consommation est de réduire les déperditions thermiques à travers l’enveloppe du bâtiment en augmentant son isolation thermique, tout en minimisant la perte de surface habitable. Dans ce contexte, les travaux de thèse portent sur l’étude et la mise au point pour pré-industrialisation de matériaux super-isolants composites à base d'aérogel de silice. Le matériau composite étudié fait partie de la famille des blankets aérogels et est obtenu via un procédé de séchage ambiant innovant. Grâce à leur faible conductivité thermique et leurs propriétés mécaniques renforcées, les blankets aérogels sont d’un grand intérêt pour l’isolation thermique qui nécessite de fines épaisseurs d’isolants. Les travaux de thèse visent dans un premier temps à effectuer une analyse des propriétés thermophysiques des blankets aérogels étudiés à la sortie du moule de fabrication et vis-à-vis de leur mise en œuvre lorsqu’ils sont soumis à différentes sollicitations (mécaniques, hygriques ...). Des travaux de modélisation du transfert de chaleur dans le blanket aérogel sont développés afin d’étudier les relations entre le transfert thermique et les paramètres morphologiques du matériau. Dans un second temps, les travaux de thèse portent sur l’étude des performances à attendre d’un système d’isolation basé sur le blanket aérogel mis en œuvre sur un bâtiment, à la fois par l’analyse du comportement thermique d’une cellule test en climat réel, ainsi que par la conduite de simulations numériques de bâtiments prenant en compte plusieurs techniques constructives, configurations de murs, et ce, pour plusieurs climats européens. Les résultats obtenus montrent que les blankets aérogels étudiés ont une très faible conductivité thermique –0,016 W.m-1.K-1– et ont un fort potentiel d’application dans l’isolation thermique du bâtiment. / Buildings are the largest energy end-use sector and account for about 40 % of the total final energy consumption in the EU-28. A short-term strategy to efficiently reduce this consumption is to decrease thermal losses through the building envelope by improving its thermal insulation, while minimizing the reduction of the available indoor living space. In this context, the thesis deals with the study and development for pre-industrialization of super-insulating composite materials based on silica aerogel. The studied material is part of the aerogel blanket family and is obtained by an innovative ambient drying process. With a very low thermal conductivity and reinforced mechanical properties, aerogel blankets are of great interest for applications where they can offer a cost advantage due to a space-saving effect. Firstly, the thesis work aims at performing analyses of the thermo-physical properties of the studied aerogel blankets at the exit of the molding and drying processes, and during application, when they are subjected to different environmental stresses (mechanical, hygric …). Heat transfer modeling is developed to study the relationship between the morphological parameters of the material and thermal transfer within it. Secondly, the thesis work focuses on the study of the expected performances of an insulating system based on the aerogel blanket, by the study of the thermal behavior of an experimental building monitored under actual climate, as well as the use of whole building energy numerical simulations taking into account several constructive techniques, different wall configurations, for various European climates. The results obtained show that the aerogel blankets studied have a thermal conductivity as low as 0.016 W.m-1.K-1 and have promising applications for building thermal insulation needs.

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