58 resultados para Craqueamento térmico


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We built an experimental house on an UFRN´s land using blocks made by a composite consisting of cement, plaster, EPS, crushed rubber and sand. Several blocks were made from various compositions and we made preliminary tests of mechanical and thermal resistance, choosing the most appropriate proportion. PET bottles were used inside the block to provide thermal resistance. In this work, a second function was given to the bottles: to serve as a docking between the blocks, because the ends of the cylinders came out of each block on top as well as at the bottom, with the bottom cut, allowing to fit of the extremities of the upper cylinder of a block in the lower holes of the other one, which were formed by the cutting already mentioned. Minimum compression tests were performed according to ABNT standards for walls closing blocks (fence). With that house built, we did studies of thermal performance in order to ascertain conditions of comfort, checking external and internal temperatures in the walls and in the ambient, among other variables, such as wind speed and relative humidity. The resulting blocks provided adequate thermal insulation to the environment, where the walls presented differences up to 11.7 ºC between the outer and inner faces, getting the maximum temperature inside the house around 31 °C, within the so-called thermal comfort zone for warm climates. At the end of the experiments it was evident the effectiveness of that construction in order to provide thermal comfort in the internal environment of the house, as well as we could confirm the viability of building houses from recyclable materials, reducing the constructive costs, becoming a suitable alternative for low- incoming families. Moreover, besides the low cost, the proposal represents an alternative use of various recyclable materials, therefore considered an ecological solution

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We present two models of blocks made of composite material obtained from the use of cement, plaster, EPS crushed, shredded tire, mud, sand and water, for the construction of popular housing. Were made metal molds for the manufacture of blocks to be used in the construction of a residence for low-income families. Performed tests of compressive strength of the composite for various formulations that met the specific standard for blocks used in construction. To study the thermal conductivity of the composite for further study of thermal comfort generated in a residence built with the proposed composite. We also determined the mass-specific and water absorption for each formulation studied. Using a home already built with another composite material, made up the closing of a window with the building blocks and found the thermal insulation, measuring external and internal temperatures of the blocks. The blocks had made good thermal insulation of the environment, resulting in differences of up to 12.6°C between the outer and inner faces. It will be shown the feasibility of using composite for the end proposed and chosen the most appropriate wording

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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

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Heterogeneous catalysts such as aluminophosphate and silicoaluminophosphate, molecular sieves with AEL of ALPO-11 and SAPO-11, were synthesized by the hydrothermal method with the following molar composition: 2.9 Al +3.2 P + 3.5 DIPA +32.5 H20 (ALPO-11); 2.9 Al +3.2 P + 0.5 Si + 3.5 DIPA +32.5 H20 (SAPO-11) starting from silica (only in the SAPO-11), pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. The crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 170ºC for a period of 48 hours under autogeneous pressure. The obtained materials were washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), thermo gravimetric differential thermal analysis (TG/DTA) and nitrogen adsorption (BET). The acidic properties were determined using adsorption of n-butylamine followed by programmed thermodessorption. This method revealed that ALPO-11 has weaker acid sites due to structural defects, while SAPO-11 shows an acidity that ranges from weak to moderate. However, a small quantity of strong acid sites could be detected there. The deactivation of the catalysts was conducted by the cracking of the n-hexane in a fixed bed continuous flow microrreator coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the regeneration and removal of the organic template

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Films of chitosan with trivalent lanthanides ions Eu3+ and Tb3+ were respectively prepared in the ratio of 3:1 m/m (chitosan: lanthanide) and 6:1 m/m (chitosan: lanthanide). There were no formations of films in a ratio of 1:1 m/m (chitosan: lanthanides). The films of chitosan with the Tb3+ ion have the same transparent appearance than the pure chitosan films. The film of chitosan with Eu3+ ion has a muddy appearance. These films present good resistance to tear. The appearance of the compounds prepared in ratio 1:1m/m is a white powder. The films and compounds of chitosan were characterized by Elementary Analysis (CHN), Thermal Analysis (TG/DTG) and Spectroscopy of Luminescence. The CHN analysis was made only for compounds prepared in ratio 1:1m/m, suggesting that these compounds possess the formula QUILn.6H2O, where QUI = Chitosan and Ln = Lanthanide. The results of the curves TG/DTG indicated that there are strong interactions between Eu3+ or Tb3+ and chitosan, causing a lesser lost of mass in the films. The luminescence analysis showed that the films of chitosan with the ions Eu3+ and Tb3+ present emissions in the region of the visible one, with bands of the chitosan and of the Eu3+ ion. The luminescence analysis of the compounds of chitosan with the Eu3+ and Tb3+ ions suggest that the chitosan does not transfer into energy to the ions lanthanides, however the chemical neighborhood around of the ion lanthanides breaks the selection rules and, conseqüently the 4f-4f transitions of the lanthanide ions are observed

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A catalyst of great interest to the scientific community tries to unite the structure of ordered pore diameter from mesoporous materials with the properties of stability and acid activity to microporous zeolites. Thus a large number of materials was developed in the past decades, which although being reported as zeolites intrinsically they fail to comply with some relevant characteristics to zeolites, and recently were named zeolitic materials of high accessibility. Among the various synthesis strategies employed, the present research approaches the synthesis methods of crystallization of silanized protozeolitic units and the method of protozeolitic units molded around surfactant micelles, in order for get materials defined as hierarchical zeolites and micro-mesoporous hybrid materials, respectively. As goal BEA/MCM-41 hybrid catalysts with bimodal pore structure formed by nuclei of zeolite Beta and cationic surfactant cetyltrimethylammonium were developed. As also was successfully synthesized the hierarchical Beta zeolite having a secondary porosity, in addition to the typical and uniform zeolite micropores. Both catalysts were applied in reactions of catalytic cracking of high density polyethylene (HDPE), to evaluate its properties in catalytic activity, aiming at the recycling of waste plastics to obtain high value-added raw materials and fuels. The BEA/MCM-41 hybrid materials with 0 days of pre-crystallization did not show enough properties for use in catalytic cracking reactions, but they showed superior catalytic properties compared to those ordered mesoporous materials of Al-MCM-41 type. The structure of Beta zeolite with hierarchical porosity leads the accessibility of HDPE bulky molecules to active centers, due to high external area. And provides higher conversion to hydrocarbons in the gasoline range, especially olefins which have great interest in the petrochemical industry

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A aplicação de isolantes térmicos em sistemas construtivos promove vantagens com vistas ao conforto térmico de ambientes. E com isso, o aumento da produtividade em locais de trabalho, a sensação de bem-estar e a diminuição dos custos com climatização. A demanda por conforto ambiental, no âmbito da isolação térmica, somada ao advento de novas leis que regulam os requisitos mínimos de conforto, as exigências dos consumidores pela adoção de métodos de produção mais “limpos”, a fiscalização quanto à destinação de resíduos industriais, além da inserção de produtos no mercado com apelos ambientais, incentivaram o desenvolvimento da presente pesquisa. O presente trabalho trata da aplicação do poliuretano, visando comparar o desempenho térmico do derivado de origem vegetal (óleo de mamona) com adição de resíduo plástico termofixo em diferentes proporções (5%, 10%, 15% e 20%), com o poliuretano petrolífero, a lã de vidro e a lã de rocha através da análise de suas propriedades térmicas (condutividade térmica – k, difusividade térmica – e capacidade calorífica – Cp). . Após a realização dos ensaios, os compósitos estudados foram moídos e reutilizados como carga para novos compósitos. Com base nos resultados dos ensaios de propriedades térmicas, constatou-se que o material desenvolvido conduz menos calor que o poliuretano de petróleo, a lã de vidro e a lã de rocha, além de oferecer alta inércia térmica, bom desempenho térmico e baixo custo. Assim como foi comprovada a possibilidade de fabricação de novos compósitos para fins de isolamento, reutilizando os compósitos testados

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The diatomite is a natural material that has numerous applications due to changes in their physical and chemical properties after processing. It is currently used in the industry as a sound insulator , filter aid and industrial load . The filter material shall be inert chemical composition , which will diatomite confers a high commercial value and performance not found in other particulate materials , for this application. The diatomite surface undergoes changes after thermal treatment at high temperatures , from 800ºC , with properties that enable its application in the food , beverage , pharmaceutical , cosmetic and textiles . In this work , we developed a study on thermal treatment on natural diatomite to adapt their properties to the application as a filter aid . The heat treatments were performed in an open oven at temperatures of 800ºC , 1000ºC and 1200ºC for a time of 24 hours. Reagents were added in the constitution of the samples analyzed. The reagents used were sodium carbonate (Na2CO3 ) and sodium chloride (NaCl) . The samples were characterized by x - ray diffraction , x -ray fluorescence , scanning electron microscopy , analysis and particle size distribution , specific surface area by the BET method , and pore volume by BJH method. The results showed a reduction in porosity of the material as well as a significant increase in specific surface area after heat treatment and the reactants in the ratio of 3 wt%. The diatomaceous earth , after heat treatment , undergone changes in its coloration , varying in white, cream and beige , which directly interferes with the speed of filtration materials process. All results obtained before and after heat treatment of the material with the values obtained for samples already used industrially , Brazilian and American industry , which were characterized using the same test methods performed with the samples in the study were compared and showed promising efficiency when material studied in the region of Punaú - RN , after processing , reagent addition and heat treatment, as an element in the composition of filter .

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This work describes the design process of a small recreational gated community in Pium, Nísia Floresta/RN, from concept to final design stages, with emphasis on low environmental impact, thermal comfort and the spatial quality of housing. The process consisted in a review of the literature and relevant standards, studies of design references and architectural programming. The project development was initially focused on the project’s feasibility, with the definition of the number of units, implantation, size and location of the dwellings and the common areas of the development. Two types of houses (four low rise and five duplex units) have been proposed in order to attend the premises of architectural programming. The conception of the architectural design began with the rooms’ zoning according to the lots. This resulted in the pre-selection of three alternatives that were evaluated in terms of spatial quality and environmental performance. The development of sketches focused on the envelope consistent with the bioclimatic guidelines and on the language of the compatible proposal with the lowest possible environmental impact of the building system, which resulted in the selection of the eucalyptus wood type. During the working drawings, the Quality Technical Regulation for the Level of Energy Efficiency Residential Buildings (RTQ -R) was adopted for the evaluation of the envelope, which resulted in "B" level of efficiency for the first case. After minor adjustments, mainly in frames, the efficiency level rose to "A", demonstrating that early project decisions contributed to the envelope energy performance. Besides the design of the two types of units, the final proposal of the gated community includes the design of the equipment for the common areas (entrance, multipurpose room and support and service sector), and the descriptive texts explaining the project and construction’s details.

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With the emergence of new technologies, has grown the need to use new materials, and this has intensified research on the collection and use of materials from renewable sources, is to reduce production costs and / or environmental impact. In this context, it was found that the sheath coconut straw, can be utilized as raw material for the production of a eco-composite that can be used as a thermal and acoustic insulator. After selected from the coconut sheaths were subjected to treatment with aqueous 2 % sodium hydroxide (NaOH). The composite study was produced with the sheath and coconut natural latex, with coconut sheath percentage in the proportions 15%, 25% and 35% of the total compound volume. Physical, thermal and acoustic properties of the composites were analyzed in order to obtain data on the use of viability as thermoacoustic insulation. The CP15 composites, CP25 and CP35 showed thermal conductivity 0.188 W/m.K, 0.155 W/m.K and 0.150 W/m.K, respectively. It can be applied as thermal insulation in hot systems to 200 ° C. The CP35 composite was more efficient as a thermal and acoustic insulation, providing 20% noise reduction, 31% and 34% for frequencies of 1 kHz, 2 kHz and 4 kHz, respectively. The analyzes were based on ABNT, ASTM, UL. Based on these results, it can be concluded that the eco-composite produced the hem of coconut can be used as thermal and acoustic insulation. Thus, it gives a more noble end to this material, which most often is burned or disposed of improperly in the environment.

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With the emergence of new technologies, has grown the need to use new materials, and this has intensified research on the collection and use of materials from renewable sources, is to reduce production costs and / or environmental impact. In this context, it was found that the sheath coconut straw, can be utilized as raw material for the production of a eco-composite that can be used as a thermal and acoustic insulator. After selected from the coconut sheaths were subjected to treatment with aqueous 2 % sodium hydroxide (NaOH). The composite study was produced with the sheath and coconut natural latex, with coconut sheath percentage in the proportions 15%, 25% and 35% of the total compound volume. Physical, thermal and acoustic properties of the composites were analyzed in order to obtain data on the use of viability as thermoacoustic insulation. The CP15 composites, CP25 and CP35 showed thermal conductivity 0.188 W/m.K, 0.155 W/m.K and 0.150 W/m.K, respectively. It can be applied as thermal insulation in hot systems to 200 ° C. The CP35 composite was more efficient as a thermal and acoustic insulation, providing 20% noise reduction, 31% and 34% for frequencies of 1 kHz, 2 kHz and 4 kHz, respectively. The analyzes were based on ABNT, ASTM, UL. Based on these results, it can be concluded that the eco-composite produced the hem of coconut can be used as thermal and acoustic insulation. Thus, it gives a more noble end to this material, which most often is burned or disposed of improperly in the environment.

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Squamous cell carcinoma of oral tongue shows high rates of morbidity and mortality in the population, therefore, great efforts are being made to classify morphological changes and identify biomarkers that have prognostic value and that are able to group patients in individualized therapeutic options. From this perspective, there is the heat shock factor 1 (HSF1), which is a heat shock factor transcription protein (HSPs) that allows the cancer to deal with stressors associated with malignancy, acting differently in tumor progression. This research aimed to perform a clinico-pathological analysis of 70 cases of oral tongue squamous cell carcinoma (OTSCC) and immunohistochemical study of the expression of HSF1 protein in OTSCC, comparing it with 30 specimens of normal oral mucosa (NOM), and correlating this immunostaining with clinico-pathological aspects of OTSCC. To analyze the association between immunoexpression of HSF1 and clinicophatoloical aspects, the cases were categorized in minor and major overexpression, based in the median immunostaining score. Regarding the cases of OTSCC, 57.1% showed clinical stage III or IV, 82.9% were graded as high grade according to Bryne (1998) and 47.1% as high risk of malignancy according to Brandwein-Gensler et al., (2005). A disease free survival rate of 47.84% and overall survival rate of 68.20% was observed in the analyzed cases, and the high degree of malignancy according to Bryne’s system (1998) (p=0.05), tumor size T3 or T4 (p=0.04), local recurrence (p=0.02), and perineural invasion (p=0.02) determined negative impacts in survival time. We observed also a statistically significant result (p<0.01) when comparing the immunoreactivity of HSF1 between NOM and OTSCC. This significantly increased expression of HSF1 in cases of OTSCC suggests that this protein acts, indeed, in the pathogenesis of this disease. However, there were no statistically significant associations between this overexpression and the clinico-pathological parameters analyzed. This finding may reflect the influence of epigenetic events on HSF1 gene or a possible stability of this protein expression throughout disease progression.

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Squamous cell carcinoma of oral tongue shows high rates of morbidity and mortality in the population, therefore, great efforts are being made to classify morphological changes and identify biomarkers that have prognostic value and that are able to group patients in individualized therapeutic options. From this perspective, there is the heat shock factor 1 (HSF1), which is a heat shock factor transcription protein (HSPs) that allows the cancer to deal with stressors associated with malignancy, acting differently in tumor progression. This research aimed to perform a clinico-pathological analysis of 70 cases of oral tongue squamous cell carcinoma (OTSCC) and immunohistochemical study of the expression of HSF1 protein in OTSCC, comparing it with 30 specimens of normal oral mucosa (NOM), and correlating this immunostaining with clinico-pathological aspects of OTSCC. To analyze the association between immunoexpression of HSF1 and clinicophatoloical aspects, the cases were categorized in minor and major overexpression, based in the median immunostaining score. Regarding the cases of OTSCC, 57.1% showed clinical stage III or IV, 82.9% were graded as high grade according to Bryne (1998) and 47.1% as high risk of malignancy according to Brandwein-Gensler et al., (2005). A disease free survival rate of 47.84% and overall survival rate of 68.20% was observed in the analyzed cases, and the high degree of malignancy according to Bryne’s system (1998) (p=0.05), tumor size T3 or T4 (p=0.04), local recurrence (p=0.02), and perineural invasion (p=0.02) determined negative impacts in survival time. We observed also a statistically significant result (p<0.01) when comparing the immunoreactivity of HSF1 between NOM and OTSCC. This significantly increased expression of HSF1 in cases of OTSCC suggests that this protein acts, indeed, in the pathogenesis of this disease. However, there were no statistically significant associations between this overexpression and the clinico-pathological parameters analyzed. This finding may reflect the influence of epigenetic events on HSF1 gene or a possible stability of this protein expression throughout disease progression.

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Nowadays, evaluation methods to measure thermal performance of buildings have been developed in order to improve thermal comfort in buildings and reduce the use of energy with active cooling and heating systems. However, in developed countries, the criteria used in rating systems to asses the thermal and energy performance of buildings have demonstrated some limitations when applied to naturally ventilated building in tropical climates. The present research has as its main objective to propose a method to evaluate the thermal performance of low-rise residential buildings in warm humid climates, through computational simulation. The method was developed in order to conceive a suitable rating system for the athermal performance assessment of such buildings using as criteria the indoor air temperature and a thermal comfort adaptive model. The research made use of the software VisualDOE 4.1 in two simulations runs of a base case modeled for two basic types of occupancies: living room and bedroom. In the first simulation run, sensitive analyses were made to identify the variables with the higher impact over the cases´ thermal performance. Besides that, the results also allowed the formulation of design recommendations to warm humid climates toward an improvement on the thermal performance of residential building in similar situations. The results of the second simulation run was used to identify the named Thermal Performance Spectrum (TPS) of both occupancies types, which reflect the variations on the thermal performance considering the local climate, building typology, chosen construction material and studied occupancies. This analysis generates an index named IDTR Thermal Performance Resultant Index, which was configured as a thermal performance rating system. It correlates the thermal performance with the number of hours that the indoor air temperature was on each of the six thermal comfort bands pre-defined that received weights to measure the discomfort intensity. The use of this rating system showed to be appropriated when used in one of the simulated cases, presenting advantages in relation to other evaluation methods and becoming a tool for the understanding of building thermal behavior

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The present research concerns about outdoor s thermal comfort conditions in hot-humid climate cities, understanding that life quality is a result of the urban object s type built for the human being in an environment with specific climate and morphological characteristics. It is presented as object of study the correlation between the neighborhood Renascença II s microclimate in São Luis /MA-Brazil, hot-humid climate city, and its urban morphological changes. As well as the thermal comfort s satisfaction level of its outdoor users. The research has as general goal to diagnosis the way these transformations caused by the urbanization influence the Renascença II s microclimate, identifying critical spots of the studied area, in order to contribute with land use recommendations based on bioclimatic architecture concepts and supply bases to urban design decisions adequate to the São Luis climate. It is presented as theoretical bases the urban climate, its concepts and elements. After that, the thermal comfort conditioners and its prediction models of thermal comfort sensation in outdoor are presented. The predictive models are presented along with bioclimatic assessment methods. Finally the use of bioclimatic assessment as an effective tool to identify places that need changes or preservation in order to seek environment quality. The applied methodology was based on the studies of Katzschner (1997), complemented by Oliveira s (1988) and Bustos Romero s (2001) studies that suggest an analysis and evaluation of maps of topography, buildings floors, land use, green areas and land covering, in order to overlap their characteristics and identify climate variable s measurements points; then a quantitative analysis of the climate variables (air temperature and humidity, wind speed and direction) of the chosen points takes place. It was perceived that Renaissance II has no permanence areas as squares or parks, its outdoor has little vegetation and presets high land impermeability and built density levels. The majority of the people interviewed said that was comfortable in a range of air temperature between 27,28ºC and 30,71ºC. The elaboration of a neighborhood master plan is important, which defines strategies for improvement of the life quality of its inhabitants