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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.
31

Sportovní centrum / Sports center

Hlaváček, Petr January 2015 (has links)
The new building sport center without cellar. The object is based on strip foundation. The footing bottom is in frost resistant depth. Construction system is in both ways. Vertical walls are made by cut bricks POROTHERM. The external cladding is replenished by thermal insulation plaster POROTHERM TO. Horizontal constructions are made by filigree ceiling panels. Stairway is made by reinforced concrete. Heating system is ensured by gas boiler.
32

Vývoj tepelně izolačních materiálů na bázi odpadních textilních vláken / Development of thermal insulating materials based on waste textile fibers

Přikrylová, Pavlína January 2017 (has links)
The increasing quantity of waste represents serious environmental, social and economic problem. Wastes produced from industry and households. A large part of the economy transforms a certain amount of raw materials to waste in their production, because it is currently emphasis is placed on finding sustainable sources of raw materials. One of the suitable secondary raw materials can be discarded textiles or waste from the textile industry. These kinds of textile waste often ends up in landfills or incinerators, so it is from an ecological and environmentally advantageous to their further use. The diploma thesis deals with the study and development of thermal and acoustic insulation materials based on textile fibers. It focuses on the legislative requirements for waste management for the sorting of textile wastes and their subsequent modification before reuse. Further it contains kinds of textile fibers and bonding technologies thermal and acoustic insulation materials. Finally, an evaluation of thermal insulation, acoustic and mechanical properties of fibrous insulation materials.
33

Acoustic and thermal properties of recycled porous media

Mahasaranon, Sararat January 2011 (has links)
This thesis is concerned with developing porous materials from tyre shred residue and polyurethane binder for acoustic absorption and thermal insulation applications. The resultant materials contains a high proportion of open, interconnected cells that are able to absorb incident sound waves through viscous friction, inertia effects and thermal energy exchanges. The materials developed are also able to insulate against heat by suppressing the convection of heat and reduced conductivity of the fluid locked in the large proportion of close-cell pores. The acoustic absorption performance of a porous media is controlled by the number of open cells and pore size distribution. Therefore, this work also investigates the use of catalysts and surfactants to modify the pore structure and studies the influence of the various components in the chemical formulations used to produce these porous materials. An optimum type and amounts of catalyst are selected to obtain a high chemical conversion and a short expanding time for the bubble growth phase. The surfactant is used to reduce the surface tension and achieve a homogenous mixing between the solid particulates tyre shred residue, the water, the catalyst and the binder. It is found that all of the components significantly affect the resultant materials structure and its morphology. The results show that the catalyst has a particularly strong effect on the pore structure and the ensuing thermal and acoustical properties. In this research, the properties of the porous materials developed are characterized using standard experimental techniques and the acoustic and thermal insulation performance underpinned using theoretical models. The important observation from this research is that a new class of recycled materials with pore stratification has been developed. It is shown that the pore stratification can have a positive effect on the acoustic absorption in a broadband frequency range. The control of reaction time in the foaming process is a key function that leads to a gradual change in the pore size distribution, porosity, flow resistivity and tortuosity which vary as a function of sample depth. It is shown that the Pade approximation is a suitable model to study the acoustic behaviour of these materials. A good agreement between the measured data and the model was attained.
34

Vibro-acoustic products from re-cycled raw materials using a cold extrusion process : a continuous cold extrusion process has been developed to tailor a porous structure from polymeric waste, so that the final material possesses particular vibro-acoustic properties

Khan, Amir January 2008 (has links)
A cold extrusion process has been developed to tailor a porous structure from polymeric waste. The use of an extruder to manufacture acoustic materials from recycled waste is a novel idea and the author is not aware of any similar attempts. The extruder conveys and mixes the particulates with a reacting binder. The end result is the continuous production of bound particulates through which a controlled amount of carbon dioxide gas that is evolved during the reaction is used to give the desired acoustic properties. The cold extrusion process is a low energy consuming process that reprocesses the post manufacturing waste into new vibro-acoustic products that can be used to meet the growing public expectations for a quieter environment. The acoustical properties of the developed products are modelled using Pade approximation and Johnson-Champoux-Allard models. Applications for the developed products are widespread and include acoustic underlay, insulation and panels in buildings, noise barriers for motorways and railway tracks, acoustic insulation in commercial appliances and transport vehicles.
35

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.

Cardoso, Grace Tiberio 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.
36

Avaliação do consumo energético em aviários Dark House, com e sem isolamento térmico: um estudo de caso na região de Palotina, Paraná / Evaluation of Energy Consumption in Poultry Dark House, with and without Thermal Insulation: A Case Study in the Region of Palotina, Paraná

Bedin, Janaina 06 March 2015 (has links)
Made available in DSpace on 2017-07-10T15:14:26Z (GMT). No. of bitstreams: 1 DissertacaoJanainaBedin.pdf: 4782834 bytes, checksum: 4c0a870502d04664c635db95ceb09e72 (MD5) Previous issue date: 2015-03-06 / The production of poultry cuts suffered major investments in technology and genetic development in recent decades, trying to adapt to the conditions and requirements of the national and world market. Studies on the production through the analysis of systems and means of accommodation, show the economic importance of the sector, which has established itself as one of the most competitive in the agribusiness sector. The present work was the study of two aviaries dark house, with and without thermal insulation in their construction, are located in the city of Palotina, Paraná, trying to evaluate the variations in temperature, gas consumption and animal performance of the two systems . In terms of methodology, both facilities were checked temperature variation, with reading by J-type thermocouple sensors and recording in datalogger; consumption of LPG, with installation of individual volumetric meters; and the animal performance and the elimination of mortality and birds, feed intake and water and weight gain. At the end of the study it can be concluded that the aviary Dark House with Thermal Insulation (DHIT) showed better animal performance indexes, lower mortality and elimination, and greater weight gain. But when evaluated performance in the face of temperature conditions, the aviary Dark House Conventional (DHC) showed better suited to the production values, as bibliographic references. / A produção de aves de cortes sofreu grandes investimentos em tecnologia e desenvolvimento genético nas últimas décadas, buscando se adequar às condições e exigências do mercado nacional e mundial. Estudos acerca da produção, através da análise dos sistemas e meios de alojamento, demonstram a importância econômica do segmento, que se consolida como um dos mais competitivos no setor agroindustrial. Assim, o presente trabalho consistiu no estudo de dois aviários dark house, com e sem isolamento térmico em suas características construtivas, localizados na cidade de Palotina, Paraná, procurando avaliar as variações de temperatura, o consumo de gás e o desempenho animal dos dois sistemas. Em termos de metodologia, em ambas instalações, foram verificados a variação de temperatura ,com a leitura por sensores Termopar tipo J e registro em datalogger; o consumo de gás GLP, com a instalação de medidores volumétricos individuais; e o desempenho animal quanto, a mortalidade e eliminação das aves, o consumo de ração e água, e o ganho de peso. Ao final da pesquisa pode-se concluir que o aviário Dark House com Isolamento Térmico (DHIT) apresentou melhores índices de desempenho animal com, menor mortalidade e eliminação, e maior ganho de peso. Porém quando avaliado o desempenho frente às condições de temperatura, o aviário Dark House Convencional (DHC) apresentou valores mais adequados à produção, conforme referencial bibliográfico.
37

Panneaux composites bio-sourcés destinés à l'isolation des bâtiments : caractérisation des ressources et procédé de production / Bio-based composite panels for building insulation : Characterization of resources and production process

Colson, Valentin 02 May 2019 (has links)
L'objectif de cette thèse est de développer de nouveaux composites isolants biosourcés à partir de coproduits de l'agriculture exploitables dans le secteur du bâtiment. Les travaux s'organisent en trois principales étapes : La première, au travers d'un travail de formulation et de caractérisation, vise à évaluer les propriétés mécaniques, thermiques et hygriques de composites biosourcés obtenus par agglomération de granulats végétaux avec différents types de liants biosourcés et minéraux. Plusieurs agro-ressources sont envisagées (paille de blé, colza, anas, chènevotte et rafles de maïs). Une solution associant des granulats de chènevotte avec un liant biosourcé thermodurcissable est sélectionnée. La suite des travaux se focalise sur la recherche d'un procédé de mise en forme adapté à la fabrication de panneaux rigides isolants réalisés à partir de la formulation du composite de chènevotte. La fabrication de panneaux composites est testée sur différents outillages disponibles en laboratoire ainsi que sur des outils industriels permettant de tester les différentes technologies existantes. La possibilité de fabriquer le panneau rigide isolant de chènevotte sur une ligne de production industrielle entièrement automatisée est démontrée. Enfin, de nouvelles solutions permettant d'améliorer la réaction au feu des panneaux composites sont testées ce qui permet d'identifier des solutions adaptées au composite étudié. / The objective of this thesis is to develop new insulation composites from agricultural by-products for building applications. The research work is divided in three main steps : The first one focuses on the formulation of bio-based composites obtained by agglomeration of vegetal aggregates with different types of binders (bio-based or mineral binders), and on the characterization of their mechanical, thermal and hygric properties. Several bio-aggregates are envisaged (wheat straw, rape straw, flax shiv, hemp shiv and corn cob). A solution combining hemp shiv aggregates bonded with a bio-based thermosetting adhesive is selected. The next step aims to identify a suitable manufacturing process to produce rigid insulation panels using the previously determined composite formulation. Several manufacturing trials are conducted on different laboratory and industrial tools which allow to experiment existing manufacturing technologies. The possibility to produce the rigid insulation panel from hemp shiv at the industrial scale on a fully automatized production line is demonstrated. Finally, new solutions to improve the fire reaction of the insulation panels are tested which allows to identify suitable solutions for the developed composites.
38

En jämförelse av koldioxidutsläpp i en byggnads klimatskal beroende på val av isoleringsmaterial / A comparison of carbon dioxide emissions in a building´s external shell related to selection of insulation materials

Rydin, Sara, Olsson, Sofia January 2019 (has links)
Syfte: En betydande del av Sveriges totala växthusgaser kommer ifrån bygg- och fastighetssektorn. Då livscykelperspektivet är ett högaktuellt ämne är det intressant att implementera LCA i bygg- och fastighetsbranschen och genomföra en analys på de isoleringsmaterial som anses vara de traditionella inom branschen. För att resultatet av LCA ska vara applicerbart för företag i branschen är det också av intresse att veta hur LCC skiljer sig mellan de jämförda isoleringsmaterialen. För att resultatet ska vara lätt att identifiera är en sammanställning av kostnad i kontrast till koldioxidutsläpp av intresse. Målet med studien är att bidra med kunskap om olika isoleringsmaterials miljöpåverkan utifrån ett livscykelperspektiv. Likaså att se hur stor skillnad det blir i kostnad mellan isoleringsmaterial med mer eller mindre koldioxidutsläpp, där en förutsättning är att U-värdet är detsamma för de jämförda materialen. Metod: De vetenskapliga metoderna för studien har varit litteraturstudie, fallstudie och dokumentanalys. Som komplement till dessa har beräkningar, livscykelanalyser och livscykelkostnadsanalyser genomförts. Resultat: Lösull av cellulosa minskar koldioxidutsläppet för isoleringen i vindsbjälklag med 94,6 procent till en kostnadsökning motsvarande 30 procent jämfört med stenull. En skiva av cellulosa minskar koldioxidutsläppet för isoleringen i yttervägg med 94,4 procent till en kostnadsökning motsvarande 7 procent jämfört med stenull. En bottenplatta av cellglas minskar koldioxidutsläppen med 65,1 procent till en kostnadsökning motsvarande 55,2 procent jämfört med en bottenplatta av cellplast och betong. Konsekvenser: • Isolering av cellulosa har ett betydligt lägre koldioxidutsläpp än stenull. • Livscykelkostnad för cellulosa är något högre än för stenull. • Utifrån denna studie rekommenderas att prioritera miljö framför kostnad och därför använda cellulosa som isolering i byggnader. • Cellglas är ett miljömässigt hållbart alternativ till cellplast och betong vid grundläggning. • Cellglas har en högre livscykelkostnad än cellplast och betong vid grundläggning. • Utifrån denna studie rekommenderas att prioritera miljö framför kostnad och därför överväga att använda cellglas vid grundläggning av byggnader. Begränsningar: Undersökningen har inte tagit hänsyn till transporter av material. Livscykelanalyserna är gjorda på 1 m2 material med en bestämd tjocklek. Endast två isoleringsalternativ per byggnadsdel har jämförts och hänsyn till materialens fukt-, ljud och brandegenskaper har inte beaktats. Studien är kvantitativ. / Purpose: A big part of the greenhouse gases from Sweden comes from the construction and real estate sector. Since the life cycle perspective is a high currant subject it is interesting to implement LCA to the building industry and perform such an analysis on the insulation materials that are traditionally used in the building industry. To make the result of the LCA applicable for companies in the industry it is also of interest to know how the LCC differs between the compared insulation materials. For the result to be easy to identify it is necessary to make a compilation of the cost in contrast to the carbon dioxide emissions. The goal of this study is to contribute with knowledge about the environmental impact from a life cycle perspective of different insulation materials. As well to see how the cost might change between different insulation materials with more or less carbon dioxide emissions, where a presumption is that the U-value is the same for the compared materials. Method: The scientific methods for the study have been literature study, case study and document analysis. As a complement, calculations, life cycle assessments and life cycle cost analysis have been made. Findings: Loose fill insulation of cellulose reduces the carbon dioxide emissions for insulation in the attic with 94,6 percent to a cost increase of 30 percent compared to stone wool. A board of cellulose reduces the carbon dioxide emissions for insulation in the external wall with 94,4 percent to a cost increase of 7 percent compared to stone wool. A foundation with foamglas reduces the carbon dioxide emissions with 65,1 percent to a cost increase of 55,2 percent compared to a foundation of EPS and concrete. Implications: • Insulation of cellulose have much lower carbon dioxide emissions than stone wool. • Life cycle cost for cellulose are a bit higher than for stone wool. • From this study the recommendation is to prioritize the environment above the cost and therefor use cellulose as insulation in buildings. • Foamglas is a more sustainable alternative to EPS and concrete for foundations. • Foamglas have a higher life cycle cost than EPS and concrete for foundations. • From this study the recommendation is to prioritize the environment above the cost and therefore consider to use foamglas for foundations. Limitations: The study has not included transportations of the materials. The life cycle assessments are made on 1 m2 of material with a fixed thickness. Only two insulation materials in each building part have been analyzed and no regards have been taken to the materials moist, sound, and fire attribute. The study is quantitative.
39

Preparation and Evaluation of New Nanoporous Silica Materials for Molecular Filtration and for Core Materials in Vacuum Insulation Panels

Twumasi Afriyie, Ebenezer January 2013 (has links)
Nanoporous materials for gas purification and thermal insulation have been studied and developed for application in many areas. It is known that a single adsorbent may not adequately control multiple contaminants. Further the utilization of nanoporous material as thermal insulator in building applications is limited due to high cost. Moreover, in view of the global environmental movement for clean air and reduction of heating energy consumption in built environment, the development of new and better nanoporous materials will not only facilitate major advances in gas adsorption and thermal insulation technology, but also meet the new challenges that cannot be met with the nanoporous materials that are currently available. This thesis presents a synthesis of new nanoporous silica based materials, and the characterization and application of these materials for molecular filtration and thermal insulation. Commercial nanoporous materials have been used for benchmarking for the pore properties, the applicability, and the performance of these new materials. First a double metal-silica adsorbent has been synthesized. The preparation procedure is based on the use of sodium silicate coagulated with various ratios of magnesium and calcium salts which yields micro-meso porous structures in the resulting material. The results show that molar ratios of Mg/Ca influence the pore parameters as well as the structure and morphology. The bimodal pore size can be tailored by controlling the Mg/Ca ratio. In the second synthesis, pure mesoporous silica, SNP has been prepared using glycerol as pore forming agent and monovalent salts as coagulant. This leads to material with large surface area and uniformed pore size centred at 43 or 47 nm.  The materials further exhibits a low bulk density in the range of 0.077 to 0.122 g/ml and possess a high porosity in the range of 95-97%. The influence of acid type (organic or inorganic) on the pore parameters and on the tapped density has also been investigated.   A synthesis method has also been developed for the preparation of carbon-silica composites. The method involves a number of routes, which can be summarised as addition of activated carbon particles to (I) the paste, (II) the salt solution, or (III) with the sodium silicate solution. In route II and III the activated carbon is present before coagulation. The routes presented here leads to carbon-silica composites possessing high micro porosity, meso porosity as well as large surface areas. The results further shows that pore size distribution may be tailored based on the route of addition of the carbon particles. Following route I and III a wide pore size (1-30 nm) was obtained whereas by route II a narrow pore size (1-4 nm) was observed.     MgCa-silica chemisorbents were also developed using either potassium hydroxide or potassium permanganate as impregnate chemicals. A direct or post-impregnation procedure was employed. The results revealed that the impregnate route and amount cause a reduction in both specific surface area and pore volume. Finally the thermal conductivity and dynamic adsorption of H2S, SO2 andtoluene were measured. Results show that at room temperature and atmospheric pressure, a thermal conductivity of 28.4 and 29.6 mW/m.K were obtained for the SNP mesoporous silicas. The dynamic adsorption behaviour of the chemisorbents and composites indicate their ability to absorbed H2S, SO2 andtoluene respectively. The highest H2S uptake corresponds to chemisorbents with 11.2-13.6 wt% KMnO4. The effect of impregnation route, amount of KMnO4 and its location in the pore system are likely the key factors in achieving a large H2S uptake. For SO2 adsorption, the highest uptake capacity was observed for MgCa-68/32-KOH. The results further suggest that the key to large SO2 uptake is as a result of the synergetic effect between large mesopore diameter and extensive mesopore volumes. Carbon-silica composites with carbon content 45 wt % exhibits high toluene adsorption with composite via route I having the highest toluene adsorption capacity (27.6 wt % relative to carbon content). The large uptake capacity of this composite was attributed to the presence of high microporosity volume and a wide (1-30 nm) bimodal pore system consisting of extensive mesopore channels (2-30 nm) as well as large surface area. These capacity values of carbon-silica composites are competitive to results obtained for commercial coconut based carbon (31 wt %), and better than commercial alumina-carbon composite (9.5 wt %). / <p>QC 20130408</p>
40

Fibras de sisal (Agave sisalana) como isolante t?rmico de tubula??es

Neira, Dorivalda Santos Medeiros 16 December 2005 (has links)
Made available in DSpace on 2014-12-17T14:57:45Z (GMT). No. of bitstreams: 1 DorivaldaSMN.pdf: 3293308 bytes, checksum: e37080f4f72e81ac421fcaf0fec21fa8 (MD5) Previous issue date: 2005-12-16 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In the last decades there was a significant increasing of the numbers of researchers that joint efforts to find alternatives to improve the development of low environmental impact technology. Materials based on renewable resources have enormous potentials of applications and are seen as alternatives for the sustainable development. Within other parameters, the sustainability depends on the energetic efficiency, which depends on the thermal insulation. Alternative materials, including vegetal fibers, can be applied to thermal insulation, where its first goal is to minimize the loss of energy. In the present research, it was experimentally analyzed the thermal behavior of fiber blankets of sisal (Agave sisalana) with and without surface treatment with oxide hidroxide (NaOH). Blankets with two densities (1100/1200 and 1300/1400 g/m2) were submitted to three rates of heat transfer (22.5 W, 40 W and 62.5 W). The analysis of the results allowed comparing the blankets treated and untreated in each situation. Others experiments were carried out to obtain the thermal conductivity (k), heat capacity (C) and the thermal diffusivity (&#945;) of the blankets. Thermo gravimetric analyses were made to the verification of the thermal stability. Based on the results it was possible to relate qualitatively the effect of the heat transfer through the sisal blankets subjected to three heat transfer rates, corresponding to three temperature values (77 ?C, 112 ?C e 155 ?C). To the first and second values of temperature it was verified a considerable reduction on the rate of heat transfer; nevertheless, to the third value of temperature, the surface of the blankets (treated and untreated) in contact with the heated surface of the tube were carbonized. It was also verified, through the analyses of the results of the measurements of k, C e &#945;, that the blankets treated and untreated have values near to the conventional isolating materials, as glass wool and rock wool. It could be concluded that is technically possible the use of sisal blankets as constitutive material of thermal isolation systems in applications where the temperature do not reach values greater than 112 ?C / Nas ?ltimas d?cadas, t?m sido grandes os esfor?os dos pesquisadores na busca por alternativas sustent?veis e conhecimentos sobre como se poder? continuar promovendo o desenvolvimento sem que isso ocorra de forma agressiva ao ambiente. Materiais oriundos de fontes renov?veis possuem grande potencial de aplicabilidade e s?o vistos como alternativas para um desenvolvimento sustent?vel. Dentre outros par?metros, a sustentabilidade depende da efici?ncia energ?tica e essa, por sua vez, depende de isolantes t?rmicos. Materiais alternativos, entre eles as fibras vegetais, podem ser aplicadas para fins de isolamento t?rmico, cujo principal objetivo ? minimizar as perdas de energia. Na presente pesquisa, analisou-se experimentalmente a aplicabilidade de mantas de fibras de sisal (Agave sisalana), in natura e com tratamento superficial com hidr?xido de s?dio (NaOH), ? isola??o t?rmica. Foram utilizadas mantas de duas gramaturas (1100/1200 e 1300/1400 g/m2) submetidas a tr?s taxas de transfer?ncia de calor (22,5 W, 40 W e 62,5 W). A an?lise dos resultados obtidos permitiu comparar a capacidade de isola??o das mantas tratada e in natura em cada situa??o. Ensaios foram realizados para determina??o da condutividade t?rmica (k), capacidade calor?fica (C) e a difusividade t?rmica (&#945;) das mantas; a estabilidade t?rmica foi verificada por meio de an?lise termogravim?trica (TGA). Com base nos resultados, foi poss?vel relacionar qualitativamente o efeito da transfer?ncia de calor atrav?s das mantas de sisal submetidas a tr?s condi??es de aquecimento, correspondentes a tr?s valores de temperatura (77 ?C, 112 ?C e 155 ?C). Nas duas condi??es iniciais, verificou-se que as mantas de sisal proporcionaram uma significativa redu??o da taxa de transfer?ncia de calor. Na terceira condi??o (155 ?C), contudo, as superf?cies das mantas (tratadas e in natura) em contato com a superf?cie aquecida do tubo ficaram carbonizadas. Por meio das an?lises dos resultados das medi??es de k, C e &#945;, constatou-se que as mantas tratadas e in natura apresentaram valores bem pr?ximos aos de materiais isolantes comerciais (l? de vidro e l? de rocha). P?de-se concluir que mantas de sisal podem ser empregadas como material constituinte de sistemas de isola??o t?rmica para aplica??es em que a temperatura n?o ultrapasse 112 ?C

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