Carbon Fibers
Mostrando 49-60 de 108 artigos, teses e dissertações.
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49. Desenvolvimento e estudo físico-químico de compósitos de nanotubos de carbono / Physical chemical study and development of carbon nanotubes composites
This thesis presents for the first time nitrogen-cup-stacked carbon nanotubes with hydrophilic and semiconducting properties synthesized by alcohol precursor. The hybrid carbon fiber/carbon nanotubes composite have three-dimensional geometry and nanostructure. The material was prepared via fixed-bed chemical vapor deposition reactor. In this process nitrogen
Publicado em: 2010
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50. Estudo da distribuição do reforço de lajes de concreto armado com fibras de carbono, usando otimização topológica / Study of the distribution of the reinforcement in reinforced concrete slabs with carbon fibers, using topology optimization
O objetivo deste trabalho é estudar a distribuição do reforço externo de lajes de concreto armado, utilizando Polímeros Reforçados por Fibras de Carbono (PRFC), através de simulações numéricas e otimização topológica. A otimização topológica entra como uma ferramenta para a determinação da distribuição ótima do reforço. Devido à alta r
Publicado em: 2010
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51. Morphological analysis of glass, carbon and glass/carbon fiber posts and bonding to self or dual-cured resin luting agents
OBJECTIVE: The aim of this study was to evaluate the morphology of glass (GF), carbon (CF) and glass/carbon (G/CF) fiber posts and their bond strength to self or dual-cured resin luting agents. MATERIAL AND METHODS: Morphological analysis of each post type was conducted under scanning electron microscopy (SEM). Bond strength was evaluated by microtensile tes
Journal of Applied Oral Science. Publicado em: 2009-10
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52. Evaluation axisymmetric analysis of thermal stress residual near fiber/epoxy interface
The finite element method is used to compute and analyze the residual stresses particularly near the fiber/epoxy interface, and these stresses need to be taken into account. An axisymmetric model has been used for stress computation and analysis, in this work two cases are considered by using an epoxy matrix with respectively glass and carbon fibers with a d
Materials Research. Publicado em: 2009-06
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53. Propriedades de filmes de amido incorporados de nanoargilas e fibras de celulose
Materials prepared from biodegradable polymers can be an alternative for reducing the environmental problems provoked by petroleum derived polymers used to produce packages. Starches from different sources have been considered as a technically viable raw material for producing biodegradable films at low cost. Moreover, starches are from renewable sources, wh
Publicado em: 2009
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54. Uso de enzinas na extração de polihidroxialcanoatos sintetizados por Cupriavidus necator
Materials prepared from biodegradable polymers can be an alternative for reducing the environmental problems provoked by petroleum derived polymers used to produce packages. Starches from different sources have been considered as a technically viable raw material for producing biodegradable films at low cost. Moreover, starches are from renewable sources, wh
Publicado em: 2009
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55. Polypyrrole and Li1.05Mn2O4 composites: preparation by dip coating or casting and electrochemical caracterization / Compósitos de Polipirrol e Li1,05Mn2O4 : preparação por dip coating ou casting e caracterização eletroquímica
Films of polypyrrole/Li1.05Mn2O4 composites were prepared by chemical synthesis over a carbon-fiber substrate, using the dipcoating and casting techniques, aiming at improving the performance of these materials as cathodes in secondary lithium or lithium-ion batteries. For this the following were investigated: i) electrochemical behavior of both materials (p
Publicado em: 2009
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56. Caracterização viscoelástica por meio de ensaios de fluência e ruptura por fluência de compósitos poliméricos de matriz de resina epoxídica e fibra de carbono / VISCOELASTIC CHARACTERIZATION OF CARBON FIBER-EPOXY COMPOSITES BY CREEP AND CREEP RUPTURE TESTS
One of the main requirements for the use of fiber-reinforced polymer matrix composites in structural applications is the evaluation of their behavior during service life. The warranties of the integrity of these structural components demand a study of the time dependent behavior of these materials due to viscoelastic response of the polymeric matrix and of t
Publicado em: 2009
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57. Evaluation of CTMP pulp´s behavior towards hydrogen peroxide bleaching: utilization of sub/supercritical carbon dioxide / Avaliação do comportamento de polpa CTMP frente ao branqueamento com peróxido de hidrogênio: utilização de dióxido de carbono no estado sub/supercrítico
The bleaching of chemithermomechanical pulp (CTMP) is usually performed using hydrogen peroxide (H2O2) in alkaline medium. This stage produces high quantity of effluent to be treated, increasing the costs of the industrial process. The usage of liquid carbon dioxide (CO2) under sub/supercritical conditions can help in reducing the amount of liquid effluents
Publicado em: 2009
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58. Removal of cyanobacteria toxins from drinking water by adsorption on activated carbon fibers
Natural fibers from macadamia nut shell, dried coconut shell endocarp, unripe coconut mesocarp, sugarcane bagasse and pine wood residue were used to prepare activated carbon fibers (ACF) with potential application for removing microcystins. The ACF from pine wood and sugar cane bagasse were used to remove [D-Leucine¹]MCYST-LR from water. After 10 minutes of
Materials Research. Publicado em: 2008-09
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59. UtilizaÃÃo de fibras de piaÃava (Attalea funifera) na preparaÃÃo de carvÃes ativados. / Utilization of piassava fibers (Attalea funifera) for activated carbons preparation.
The piassava fibers, piassava broom production waste, were used as a precursor to prepare activated carbons. The activated carbons were prepared by chemical activation with zinc chloride, phosphoric acid and iron chloride and by physical activation with carbon dioxide and water steam. The resulting activated carbons were characterized by N2 adsorption/desorp
Publicado em: 2008
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60. Casca de arroz processada via enzimólise como fonte de carbono para produção de celulose por Acetobacter xylinum / Rice husk processed with hidrolityc enzimes as source of carbon for the production of bacterial cellulose by Acetobacter xylinum
Bacterial cellulose (BC) has been applied in the electronic industry and in medicine as a wound dressing film. However, the high manufacturing cost limits its wide-scale use. To reduce the costs of the process and obtain a differentiated product, this work proposes the use of rice husk as a substrate for the production of BC, since it consists of minerals, c
Publicado em: 2008