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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.
41

Estudo de um isolante t?rmico para tubos fabricado em material comp?sito / Estudo de um isolante t?rmico para tubos fabricado em material comp?sito

Santana, Jos? Jorge Barros de 06 June 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:15Z (GMT). No. of bitstreams: 1 JoseJBS_DISSERT.pdf: 2506780 bytes, checksum: d6a8e17babc22c04b62e29971d6d4c29 (MD5) Previous issue date: 2011-06-06 / It presents a new type of insulation for ductwork hot water, which can be used in solar systems for heating water, which consists of a composite of different compositions based on plaster, cement and EPS ground, palm and water. This composite has as its main features easy assembly and manufacturing processes and low cost. Comparative results will be presented on the tests of materials and thermal tubes proposed. Four formulations were used to manufacture tubes with three diameters 70, 65 and 42mm. It was also tested conventionally used for elastomeric foam insulation to 110 ? C, for a comparative analysis with the composite pipe insulator proposed. It will demonstrate that the cost of manufacturing of such tubes is competitive with alternative elastomeric foam tested, but results of the composite tube to the temperature range studied, are lower. Another drawback of the composite insulator tube is its large mass. It would be important to test such a composite for greater levels of temperature to a diagnostic technique competitive with conventionally used insulators. A positive factor of using the proposed composite-tube would be the recycling of EPS so damaging to the environment, representing an environmentally friendly application of science / Apresenta-se um novo tipo de isolamento t?rmico para tubos condutores de ?gua quente, que pode ser utilizado em sistemas solares para aquecimento de ?gua, que consiste de um comp?sito, de diferentes formula??es, ? base de gesso, cimento , EPS triturado, dend? e ?gua. Tal comp?sito tem como principais caracter?sticas seus f?ceis processos de fabrica??o e montagem de baixo custo. Ser?o apresentados resultados comparativos relativos aos ensaios t?rmicos e de materiais dos tubos propostos. Foram utilizadas quatro formula??es para a fabrica??o dos tubos, com tr?s di?metros 70, 65 e 42mm. Foi tamb?m testada a espuma elastom?rica convencionalmente utilizada para isolamento t?rmico at? 110?C, para uma an?lise comparativa com o tubo comp?sito isolante t?rmico proposto. Demonstrar-se-? que o custo de fabrica??o de tais tubos alternativos ? competitivo com a espuma elastom?rica ensaiada, por?m os resultados do teste de resist?ncia t?rmica do tubo comp?sito, para a faixa de temperatura analisada, s?o inferiores. Um fator positivo da utiliza??o do tubo-comp?sito proposto seria a reciclagem do EPS t?o danoso ao ambiente, representando uma aplica??o cient?fica ambientalmente correta
42

Caracterização da espuma rígida de poliuretano (PU) derivada de óleo de mamona para isolamento térmico na construção civil / Characterization of rigid foam polyurethane (PU) derived from castor oil for building insulation.

Grace Tiberio Cardoso 19 November 2010 (has links)
Este trabalho teve como objetivo o estudo da espuma rígida de poliuretano (PU) derivada de óleo de mamona para aplicação como forro na isolação térmica de sistemas de cobertura. Dentro deste objetivo foram caracterizadas as suas propriedades termomecânicas e avaliado o seu comportamento térmico quando aplicada como forro em células de teste em quatro situa-ções diferentes. As caracterizações termomecânicas da espuma rígida de poliuretano derivada de óleo de mamona foram realizadas utilizando as técnicas Termogravimétrica (TGA), Dinâ-mico-Mecânica (DMA), e Método do Fio Quente Paralelo. A técnica Termogravimétrica (TGA) possibilitou o estudo da decomposição da espuma e uma avaliação de sua cinética. A cinética de decomposição foi realizada em quatro diferentes razões de aquecimento e os resul-tados foram avaliados utilizando o método baseado no modelo de Ozawa-Flynn-Wall no qual foi possível estimar o tempo de vida da espuma rígida de poliuretano para vários valores de temperatura constante. Por meio da utilização da técnica Dinâmico-Mecânica (DMA) foi pos-sível determinar a temperatura de transição vítrea da espuma e os módulos viscoelásticos de armazenamento (E) e de perda (E) assim como os valores de Tan Delta. O Método do Fio Quente Paralelo proporcionou a determinação do valor da condutividade térmica da espuma, que a classificou como um material muito isolante (1).A espuma rígida de poliuretano apre-sentou propriedades termomecânicas compatíveis para utilização como isolante térmico em temperaturas abaixo da ambiente, e em temperaturas acima de 100 oC. O estudo comparativo entre quatro células de teste para análise do comportamento térmico do forro foi feito com a coleta de dados em canteiro experimental. Os resultados obtidos comprovaram a eficiência da espuma rígida de poliuretano derivada do óleo de mamona na redução da entrada de calor durante o período de radiação solar global máxima e a atenuação da perda de calor no período sem influência da radiação solar / This work aimed to study the rigid foam polyurethane (PU) derived from castor oil for appli-cation as lining in thermal insulation systems coverage. Within this objective we have charac-terized the thermomechanical properties and assessed its thermal behavior when applied as lining cells testing in four different situations. The rigid foam polyurethanes thermo characte-rizations, derived from castor oil, were performed using the Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), and Hot Parallel Wire Method. The Thermo-gravimetric Analysis (TGA) has enabled the study of the foams decomposition and an evalu-ation of its kinetics. The decomposition kinetics was carried out in four various heating rea-sons and the results were evaluated using the method based on Ozawa-Flynn-Wall model which it was possible to estimate the rigid foam polyurethanes lifetime for various constant temperature values. By Dynamic Mechanical Analysis (DMA) has been possible to determine the foams glass transition temperature and the viscoelastics modules, storing module (E\') and loss module (E) well as the values of Tan Delta. The Hot Parallel Wire Method provided the valuation of foams thermal conductivity which ranked as a very insulating material (1). The rigid foam polyurethane has been shown to thermomechanical compatible for used as an insu-lator heat at temperatures below ambient, and temperatures above 100 oC. The four test cells comparative study for linings thermal behavior analysis was made with the collecting data from experimental plot. Results obtained proved the rigid foam polyurethane efficiency, de-rived from castor oil, in reducing the input heat during the maximum solar radiation and at-tenuation of heat loss in the period with no influence of solar radiation.
43

Análise numérica da transferência de calor de um cilindro horizontal isotérmico isolado excentricamente por convecção natural e radiação / Numerical analysis of the heat transfer in horizontal isothermal eccentrically insulated cylinder by free convection and radiation

Malateaux, Ezequiel Costa, 1987- 23 August 2018 (has links)
Orientador: Luiz Fernando Milanez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T05:12:48Z (GMT). No. of bitstreams: 1 Malateaux_EzequielCosta_M.pdf: 98402739 bytes, checksum: 8bb545a108688271a9e6d884f1c8ac49 (MD5) Previous issue date: 2013 / Resumo: A transferência de calor em cilindros horizontais isolados é de grande importância na indústria tanto no caso em que se pretende minimizar a dissipação térmica (quando dutos isolados são usados no transporte de fluidos), como quando se pretende maximizá-la (no caso de cabos de eletricidade revestidos, por exemplo). Em ambas as situações, convecção natural e radiação térmica estão presentes, podendo ser consideradas como os principais mecanismos envolvidos de dissipação térmica. Normalmente o isolamento térmico é circular e concêntrico ao cilindro. No entanto, o coeficiente convectivo e a temperatura da superfície não são constantes ao redor do cilindro, levando a crer que a adoção de isolantes concêntricos pode não ser o melhor método de se distribuir o isolante. Assim, se um isolamento excêntrico for adotado, a temperatura superficial deve apresentar variação ainda maior, alterando o escoamento ao redor do cilindro e, portanto, as perdas térmicas. No presente trabalho é apresentada uma análise numérica da dissipação térmica em cilindros horizontais isotérmicos isolados excentricamente expostos a convecção natural (Pr= 0,715) e a radiação. A condução na camada de isolante foi resolvida analiticamente (através do uso do sistema de coordenadas bicilíndricas) e integrada numericamente. A partir da temperatura obtida para a superfície externa do isolante, o software PHOENICS foi utilizado para resolver o problema de convecção natural, fornecendo um novo perfil para o coeficiente convectivo. Para cada caso, algumas iterações foram necessárias para se alcançar a convergência. Os parâmetros analisados são a emissividade da superfície externa, a razão entre os raios externo e interno do isolante, a razão entre as condutividades térmicas do isolante e do ar, o número de Rayleigh (definido de forma a ser independente dos outros parâmetros) e a excentricidade do isolante. A dissipação e a temperatura superficial local são mostradas graficamente, assim como os campos de temperatura e velocidade do escoamento. Uma equação é sugerida para a determinação da influência da excentricidade sobre o calor total dissipado em função da razão entre as resistências térmicas de convecção natural-radiação e a resistência térmica de condução, para determinada razão de raios e excentricidade / Abstract: Heat transfer in horizontal insulated cylinders is of importance in industry as when one wants to reduce the heat dissipation (when insulated ducts are used to transport fluids), as when one wants to enhance it (in the case of covered electric cables, for example). In both cases, free convection and thermal radiation are present and can be considered as the main mechanisms of heat dissipation. Generally, the insulating layer is round and is arranged concentrically in the cylinder. However, the heat transfer coefficient and the surface temperature are not constant around the cylinder, raising the point that the use of concentric insulation may not be the best way to arrange the insulating layer. Thus, if an eccentric layer is used, the surface temperature should have a larger variation, changing the flow around the cylinder and, therefore, the heat dissipation. A numerical analysis of the heat dissipation in horizontal isothermal eccentrically insulated cylinders exposed to free convection (Pr= 0,715) and radiation is presented. The conduction through the insulating layer was solved analytically (using the bicylindrical coordinate system) and integrated numerically. From the solution for the surface temperature, the PHOENICS software was used to solve the problem of free convection, giving a new profile for the heat transfer coefficient. For each case, some iterations were necessary to reach convergence. The parameters analyzed were the emissivity of the external surface, the ratio between the outer and the inner radius of the insulating layer, the ratio between the insulation and the air thermal conductivities, the Rayleigh number (defined in such a way to be independent of the other parameters) and the eccentricity of the insulation. The heat dissipation and the surface temperature are shown graphically, as well as the temperature and velocity flow fields. An equation is suggested to define the importance of the eccentricity over the total heat as a function of the ratio between the free convection-radiation thermal resistance and the conduction thermal resistance, for a given ratio of radius and eccentricity / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
44

Isolamento térmico com material reciclado em escamoteadores aquecidos / Thermal insulation with recycled material in heated creep

Sartor, Karina, 1983- 28 August 2018 (has links)
Orientador: Luiz Antonio Rossi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-28T04:23:54Z (GMT). No. of bitstreams: 1 Sartor_Karina_M.pdf: 1616477 bytes, checksum: 8bc1c2182f361f23bdb743e97299dedb (MD5) Previous issue date: 2015 / Resumo: Os leitões recém-nascidos possuem baixa capacidade de reter calor corporal em razão do menor isolamento térmico pelo pouco tecido adiposo, pouca cobertura de pelos e maior superfície corporal em relação ao peso. A ausência de conforto térmico aos leitões em fase de maternidade provoca redução do peso ao desmame e susceptibilidade a doenças. A manutenção do conforto térmico para os leitões lactentes exige alta demanda energética para promover o aquecimento do escamoteador. O experimento foi conduzido na sala maternidade em granja comercial objetivando avaliar a eficiência térmica do isolamento com a placa ecológica Tetra Pak® no revestimento do escamoteador para promover o conforto térmico dos leitões e uso racional de energia elétrica. Foram mensurados os parâmetros climáticos no interior do escamoteador, temperatura superficial do piso, temperatura superficial de pele, episódios comportamentais, ganho de peso dos leitões e eficiência energética. Os resultados obtidos com o estudo demonstraram que o revestimento do escamoteador com isolante térmico manteve a temperatura de conforto térmico dos leitões lactentes. A temperatura superficial de pele e os episódios comportamentais dos leitões lactentes foram normais. O ganho de peso foi similar nos dois tratamentos. A utilização da placa Tetra Pak® como isolante térmico no revestimento do escamoteador para leitões lactentes mostra eficiência térmica e energética / Abstract: The newborn piglets exhibit low ability in retaining body heat which is associated to the lower thermal insulation offered by the thin fat layer, little hair coverage and greater body surface area to weight ratio. The absence of thermal comfort at the maternity phase causes weight reduction of piglets at weaning as well as susceptibility to diseases. Thermal comfort for suckling piglets demands high energy to promote heating creep area. The experiment was carried out in the maternity room of a commercial farm to evaluate the thermal insulation efficiency with the ecological Tetra Pak® plaque thermal efficiency to promote thermal comfort to the piglets as well as rational use of electricity. Climatic parameters were read inside the creep area, floor surface temperature, skin surface temperature, behavioral episodes, piglets weight gain and energy efficiency. The results of this study showed that the creep area of the coating insulator maintained the temperature improving thermal comfort to the suckling piglets. The skin surface temperature and the behavioral episodes of suckling piglets were noted to be normal. Weight gain was similar for both treatments. The use of Tetra Pak® plaque as thermal insulation in creep area flooring for suckling piglets showed thermal and energy efficiency / Mestrado / Construções Rurais e Ambiencia / Mestra em Engenharia
45

Penzion s restaurací / Guesthouse with Restaurant

Kyška, Roman January 2020 (has links)
The diploma thesis deals with the proposal of a new guesthouse with a restaurant. The building is located in a slightly sloping terrain in the cadastral area of the village Vlasatice Brno-venkov in the South Moravian Region in the Czech Republic. The ground-plan shape of the building is mostly rectangular with folded facade parts. It is a partially basement building, to a lesser extent, recessed below ground level with three above-ground floors. The pension has a total of 22 rooms with a total capacity of 46 persons for short-term accommodation. Four rooms on the first floor are designed as wheelchair accessible. For the proper operation of the pension there is a reception on the first floor and an office with the appropriate meeting room on the second floor. One-storey part of the building consists of a restaurant with a capacity of 76 persons, which is designed as a frame skeleton with intensive vegetation single-skin flat roof. The preparation and meals and service of the restaurant is ensured by the kitchen together with its operations and respective warehouses located on the first floor. The basement is used primarily for the operation of the guesthouse, which is located air-conditioning engine room, utility room, workshop or warehouse. The building is for the most part bricked and the peripheral, internal bearing or partition walls are made of polished ceramic blocks porotherm. External walls are insulated with contact insulation system ETICS of gray EPS polystyrene. The glazed Schüco façade is used as the shell of the skeleton structure. The construction of the ceiling is composed of filigree ceiling panels and a singlelayer flat roof with a slope of 3% is used for roofing the building. The thesis contains project documentation for the realization of the construction.
46

Posouzení vlivu provedení zateplení bytového domu v Třebíči na výdaje spojené s provozem této nemovitosti / Assessment of the Impact of Thermal Insulation Performance of a Residential Building in Trebic on Running Expenses of this Property

Kostíková, Veronika January 2012 (has links)
This thesis evaluates the influence of thermal insulation of residential building design for expenses associated with operating the property. The thesis first analyzes the current problems in our panel construction, basic concepts related to energy performance of buildings and methods of supplying heat to the building. Is discussed in more detail the way the building insulation using ETICS. In assessing the economic returns are two options proposed austerity measures. The work includes Energy Performance Certificate apartment house, on the basis of the assessed amount of energy saved for the variations of thermal insulation. Both variants are also measured by isolating the needs for economic evaluation. The conclusion assesses the turnaround time of each action.
47

Hotel Artia / Hotel Artia

Bína, Vojtěch January 2016 (has links)
The final thesis „Hotel Artia” is processed in the form design documentation for building construction. The building of hotel is located on plot no. 443/1 in Červená Řečice. The building has four-storey part of hotel and single-storey part of restaurant. Structural system is RC frame. The building has warm flat roof and contact thermal insulation.
48

Novostavba mateřské školy / New build kindergarten

Janoušková, Dominika January 2017 (has links)
The thesis deals with the desing of new kindergarten in Hlinsko. The building is on the outskirt of the Down, street Družstevní. The house is basementless, has twou floors and a flat foor. The building is made from constructional system Porothem, the facade is designed with an external thermal insulation composite system. On the firt floor there are a childrenś department and technical department with kitchen. On the second, there are two childernś departments. The building is processed in the Archicad 14.
49

Les aérogels de pectine : matériaux avancés pour l'isolation thermique et la libération de médicaments / Pectin aerogels : advanced materials for thermal insulation and drug delivery

Groult, Sophie 28 May 2019 (has links)
Les aérogels sont des matériaux nano-structurés ultralégers, hautement poreux et présentant une surface spécifique élevée. Les bio-aérogels sont une nouvelle génération d'aérogels entièrement bio-sourcés, offrant de ce fait de grands potentiels pour des applications à l’interface avec le vivant tout en valorisant la biomasse. Dans le cadre de cette thèse, la pectine a été utilisée pour produire des bio-aérogels. Deux principaux objectifs ont été atteints : • Le premier était de déterminer et de maîtriser les corrélations existantes entre les caractéristiques de la pectine et les conditions de préparation d’une part, avec la structure interne de l'aérogel et ses propriétés physico-chimiques d’autre part. • Le second était d’évaluer et développer les aérogels de pectine pour deux applications distinctes : l'isolation thermique et la libération de médicaments. Il a été établi que les différents mécanismes de formation du réseau, la gélification et la séparation de phase, jouaient un rôle majeur sur la morphologie et les propriétés finales de l'aérogel. La conductivité thermique des aérogels de pectine s'est révélée très faible, de l'ordre de 0,015 à 0,020 W/(m.K), et a présenté une courbe de dépendance en forme de U avec leurs densités. Les aérogels ont également été utilisés en tant que matrices supports de médicament. Les cinétiques de libération du médicament en milieu liquide ont été corrélées aux structures et densités des aérogels de pectine. Des aérogels composites, de type cellulose-pectine et silice-pectine, ont été préparés et utilisés comme supports de médicament menant à une libération prolongée du principe actif dans le temps. Dans cette thèse, nous avons mis en évidence le potentiel élevé des aérogels de pectine utilisés en tant que biomatériaux avancés, versatiles et aux fonctionnalités ajustables. / Aerogels are ultra-light, highly porous and nano-structured materials with high specific surface area. Bio-aerogels are a new generation of aerogels that are fully biomass-based, which opens up a lot of potentials in biomass valorization and life science applications. In this work pectin was used to produce bio- aerogels. Two main objectives were achieved : • The first was to understand and correlate the characteristics of pectin and the preparation conditions with the internal structure of aerogel and its physico-chemical properties. • The second was to evaluate and develop pectin aerogels as advanced bio-materials for the two different applications : thermal insulation and drug delivery. Various mechanisms of network formation, gelation and non-solvent induced phase separation, were demonstrated to play a very important role in aerogel morphology and properties. Thermal conductivity of pectin aerogels was very low, around 0.015 - 0.020 W/(m.K), and showing U-shape dependence on density. When used as drug delivery matrices, the kinetics of drug release was correlated with pectin aerogels’ structure and density. Composite cellulose-pectin and silica-pectin aerogels were synthesized and also used as drug carriers; a prolonged release was recorded. A high potential of pectin aerogels to be used as versatile bio-materials with advanced tunable functionalities was demonstrated.
50

Thermally insulating carbon foams from carbonized kraft lignin / Värmeisolerande kolskum från karboniserat kraftlignin

Hernodh Svantesson, Isabelle January 2021 (has links)
Kolmaterial, såsom kolfibrer och kolskum, används som värmeisolatorer i applikationer vid höga temperaturer. För närvarande härleds dessa material från fossilbaserade källor, vilket tyder på ett behov av att hitta alternativa kandidater baserade på förnybara källor. Detta examensarbete undersökte möjligheten att använda kraftlignin som ett förnyelsebart startmaterial för framställning av kolskum med värmeisoleringsegenskaper. Två kraftligniner av barrträd med olika molekylvikter och ett kraftlignin av lövträd användes. De tre kraftligninerna karboniserades vid 1000°C efter att ha blandats i olika förhållanden och kombinationer (formuleringen av råmaterialet). Formuleringen av råmaterialet påverkade densiteten och porositeten hos de erhållna materialen, vilket i sin tur ledde till skillnader i kompressionsstyrkan och värmeledningsförmågan hos de erhållna kolskummen. Kolskummen hade olika värmeledningsförmåga (0,11-0,35 W/mK), porositet (80,55-97,53%) och densitet (0,08-0,42 g/cm3). För skummet med den högsta densiteten uppskattades krossstyrkan till cirka 10,03 MPa vilket är jämförbart med kommersiellt använda kolskum för högtemperaturisolerande applikationer. Kolskummens värmeledningsförmåga var inom omfånget för kommersiellt använda kolskum för högtemperaturapplikationer. Detta arbete visar möjligheten att tillverka kolskum från 100% kraftlignin som har liknande egenskaper som kommersiellt tillgängliga termiska isoleringsmaterial för högtemperaturapplikationer. / Carbon materials, such as carbon fibres and carbon foams, are used as thermal insulators in high-temperature applications. At present, these materials are derived from fossil-based sources, which suggests a need of finding alternatives candidates based on renewables. This thesis work investigated the possibility of using kraft lignin as a renewable starting material for the preparation of carbon foams with thermal insulation properties. Two softwood kraft lignins with different molecular weights and a hardwood kraft lignin were used. The three kraft lignins were carbonized at 1000°C after being mixed in different ratios and combinations (precursor formulation). The precursor formulation affected the density and porosity of the obtained materials, which in turn led to differences in compression strength and thermal conductivity of the carbon foams derived. The obtained carbon foams had different thermal conductivities (0.11-0.35 W/mK), porosity (80.55-97.53%) and density (0.08-0.42 g/cm3). For the foam with the highest density, the crushing strength was estimated to approximately 10.03 MPa which is comparable to commercially used carbon foams for high-temperature insulating applications. The thermal conductivity of the prepared carbon foams was in the range of commercially used carbon foams for high-temperature applications. This work demonstrates the possibility of preparing carbon foams from 100% kraft lignin which has properties similar of commercially available insulating materials for high-temperature applications.

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