878 resultados para Polímero reforçado com fibras de vidro
Resumo:
Pós-graduação em Química - IQ
Resumo:
The objective of this paper is to realize the preliminary cogeneration project, to be applied on the output of a float glass furnace, aiming the energetic use of the furnace's by-products in other relevant applications on the site. It was analyzed the main points where the cycle could be installed and also the available technologies to energy recovery. After, it was chosen the installation point and the technology to be projected, evaluated the electric power generated and the cycle efficiency. Finally it was evaluated economical indicators in order to verify the project's economical feasibility
Resumo:
The object of this study is a glass heating machine for rolling process, designed in 2006 and which is manufactured regularly. By customer request it is intended to increase the production capacity of this machine. However, initial tests have shown that the existing heat exchanger cannot supply the necessary thermal energy demand. A study of the thermal characteristics of the equipment was performed in order to obtain the required information to study alternatives for expanding its capacity taking into account space limitations and the need to rationalize costs, avoiding unnecessary oversizing
Resumo:
Natural fibers have been highlighted as a renewable material that can replace materials from oil and its derivatives. In this context, Brazil becomes the perfect setting because of the diversity of fibers found in its territory, such as sugarcane, sisal, rice, cotton, coconut, pineapple, among others. The paineiras (Chorisia speciosa St. Hil) are typically Brazilian trees, which produce paina as fruit. These fruits are still little studied as a source of lignocellulose by research groups. This project aimed obtaining and characterization of cellulose nanofibers from the fibers from the paina fibers. Obtaining nanocellulose is practically made through simplified chemical processes. First, was performed out pre-treatments to removal of waxes, lignin and hemicellulose. The first stage of pre-treatment was carried out by alkaline aqueous solution of sodium hydroxide (NaOH) at 5wt%, where the fibers were under constant agitation for 1h at 70°C. Through alkali treatment it was possible to remove most of the lignin, hemicellulose, waxes and extractives. After the alkaline treatment was done bleaching with an aqueous solution of sodium hydroxide (NaOH) to 4wt% and hydrogen peroxide (H2O2) to 24wt% 1:1 during 2h with constant stirring to 50 °C. Through bleaching was possibe to remove residual lignin, and got cellulose with 72% of crystallinity. Nanocellulose of paina fibers was extracted using different conditions of acid hydrolysis with sulfuric acid (H2SO4) to 50wt%. After acid hydrolysis, the suspensions were centrifuged during 30 min and dialyzed in water to remove excess acid until neutral pH (6-7). Then the suspensions were passed by ultrasonification in an ultrasound 20 kHz during 1h in an ice bath. Untreated, alkalinized and bleached fibers as well as cellulose nanoparticles were characterized by the techniques of thermogravimetry ... (Complete abastract click electronic access below)
Resumo:
Pós-graduação em Agronomia (Proteção de Plantas) - FCA
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Pós-graduação em Química - IQ
Resumo:
The objective of this paper is to realize the preliminary cogeneration project, to be applied on the output of a float glass furnace, aiming the energetic use of the furnace's by-products in other relevant applications on the site. It was analyzed the main points where the cycle could be installed and also the available technologies to energy recovery. After, it was chosen the installation point and the technology to be projected, evaluated the electric power generated and the cycle efficiency. Finally it was evaluated economical indicators in order to verify the project's economical feasibility
Resumo:
The object of this study is a glass heating machine for rolling process, designed in 2006 and which is manufactured regularly. By customer request it is intended to increase the production capacity of this machine. However, initial tests have shown that the existing heat exchanger cannot supply the necessary thermal energy demand. A study of the thermal characteristics of the equipment was performed in order to obtain the required information to study alternatives for expanding its capacity taking into account space limitations and the need to rationalize costs, avoiding unnecessary oversizing
Resumo:
Natural fibers have been highlighted as a renewable material that can replace materials from oil and its derivatives. In this context, Brazil becomes the perfect setting because of the diversity of fibers found in its territory, such as sugarcane, sisal, rice, cotton, coconut, pineapple, among others. The paineiras (Chorisia speciosa St. Hil) are typically Brazilian trees, which produce paina as fruit. These fruits are still little studied as a source of lignocellulose by research groups. This project aimed obtaining and characterization of cellulose nanofibers from the fibers from the paina fibers. Obtaining nanocellulose is practically made through simplified chemical processes. First, was performed out pre-treatments to removal of waxes, lignin and hemicellulose. The first stage of pre-treatment was carried out by alkaline aqueous solution of sodium hydroxide (NaOH) at 5wt%, where the fibers were under constant agitation for 1h at 70°C. Through alkali treatment it was possible to remove most of the lignin, hemicellulose, waxes and extractives. After the alkaline treatment was done bleaching with an aqueous solution of sodium hydroxide (NaOH) to 4wt% and hydrogen peroxide (H2O2) to 24wt% 1:1 during 2h with constant stirring to 50 °C. Through bleaching was possibe to remove residual lignin, and got cellulose with 72% of crystallinity. Nanocellulose of paina fibers was extracted using different conditions of acid hydrolysis with sulfuric acid (H2SO4) to 50wt%. After acid hydrolysis, the suspensions were centrifuged during 30 min and dialyzed in water to remove excess acid until neutral pH (6-7). Then the suspensions were passed by ultrasonification in an ultrasound 20 kHz during 1h in an ice bath. Untreated, alkalinized and bleached fibers as well as cellulose nanoparticles were characterized by the techniques of thermogravimetry ... (Complete abastract click electronic access below)
Resumo:
Pós-graduação em Agronomia (Proteção de Plantas) - FCA
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
OBJETIVO: Determinar a reprodutibilidade da espessura da camada de fibras nervosas da retina peripapilar e dos parâmetros da cabeça do nervo óptico em olhos normais, utilizando a tomografia de coerência óptica de domínio espectral (SD-OCT). MÉTODOS: Trinta e quatro olhos de 34 indivíduos saudáveis foram incluídos no estudo. O protocolo do cubo do disco óptico 200x200 do OCT Cirrus foi utilizado para gerar 3 imagens de cada olho para avaliar a reprodutibilidade. O coeficiente de correlação intraclasse (ICC) foi calculado para as medidas da espessura da camada de fibras nervosas da retina e da cabeça do nervo óptico. RESULTADOS: A correlação foi excelente para todas as medidas da espessura da camada de fibras nervosas da retina (ICC entre 0,87 e 0,98). O mesmo ocorreu com os parâmetros da cabeça do nervo óptico que, com exceção da razão E/D vertical (ICC 0,56), apresentou ICC entre 0,83 e 0,99. CONCLUSÃO: As medidas de espessura da camada de fibras nervosas da retina peripapilar e os parâmetros da cabeça no nervo óptico demonstraram uma excelente reprodutibilidade com o OCT Cirrus, indicando que este aparelho poderá ser uma ferramenta útil no estudo do glaucoma. Este estudo apresenta algumas limitações, como o pequeno número de casos avaliados, sendo necessários maiores estudos para corroborar nossos achados.
Resumo:
Objetivo: elaborar um manual com alimentos fonte de fibras para ser usado na composição da dieta líquida homogênea dos pacientes em pós-operatório no HRAC, de todas as idades, para reduzir ou prevenir a constipação intestinal. Métodos: o manual contém temática que esclarece sobre a importância das fibras alimentares, classificação, fontes, quantidades de uso, interação com outros nutrientes, forma de preparo, solubilidade, funções e problemas causados pelo excesso de ingestão. Consta também de uma lista de alimentos com quantidades de fibras presentes por 100gramas de cada alimento. Tais dados foram retirados da Tabela Brasileira de composição de Alimentos da UNICAMP e da Tabela Brasileira de Composição de Alimentos da USP. O manual foi elaborado pelas alunas do programa de Aprimoramento Profissional Fundap e será distribuído gratuitamente para todos os pacientes em pós-operatórios submetidos à dieta líquida homogênea. Além disto, o manual será disponibilizado nos sites www.centrinho.usp.br/manual e www.redeprofis.com.br. para consulta e cópias gratuitas. A arte e as ilustrações do manual foram feitas por aluno do Curso de Publicidade e Propaganda da USC. Resultados: O uso das fibras será orientado de forma preventiva para os pacientes que não apresentam constipação intestinal e de forma corretiva para os já constipados. Conclusões: A constipação intestinal é um problema de saúde pública no Brasil, principalmente entre as mulheres e tem seu quadro agravado quando estes indivíduos são submetidos a dietas líquidas e homogêneas, aonde os alimentos são liquidificados e coados e os resíduos (fibras) desprezados. Sendo assim, a composição desta dieta tem que ser enriquecida com fibras alimentares para prevenir ou corrigir a constipação intestinal.