Hemicelluloses
Mostrando 13-24 de 58 artigos, teses e dissertações.
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13. Aplicação de enzimas, extração e adição de hemiceluloses combinadas com ondas ultrassônicas para desenvolvimento de propriedades de papéis reciclados / Enzymes application, extraction and addition of hemicelluloses combined with ultrasonic wavez to develop recycled paper properties
Objetivou-se com este estudo a avaliação da capacidade de recuperação das propriedades dos papéis formados a partir de aparas de papelão ondulado pós-consumo pela combinação de diferentes técnicas. Para tanto, avaliou-se os efeitos da ação de diferentes grupos de enzimas, da extração e adição de hemiceluloses, do refino em moinho PFI e ultras
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/01/2011
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14. Determinação de constituintes químicos em madeira de eucalipto por Pi-CG/EM e calibração multivariada: comparação entre redes neurais artificiais e máquinas de vetor suporte
Multivariate models were developed using Artificial Neural Network (ANN) and Least Square - Support Vector Machines (LS-SVM) for estimating lignin siringyl/guaiacyl ratio and the contents of cellulose, hemicelluloses and lignin in eucalyptus wood by pyrolysis associated to gaseous chromatography and mass spectrometry (Py-GC/MS). The results obtained by two c
Química Nova. Publicado em: 2011
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15. Desenvolvimento de propriedades de papéis reciclados por tratamento ultrassônico e adição de xilanas / Development of recycled paper properties by ultrasonic treatment and xylans addiction
This study evaluates the potential of ultrasonic treatment and hemicelluloses addiction to develop mechanical properties of recycled papers. Initially a study was conducted which aimed to determine the better condition to performing the ultrasonic treatment. Were evaluated the effect of pH, pulp consistency and treatment time. Pulp consistency didnt affect t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/07/2010
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16. Propriedades de madeiras termorretificadas / Properties of thermalrectified wood
Heat treatment applied to the wood leads to the degradation and/or rearrangement of its principal chemical constituents, especially cellulose, hemicelluloses, and lignin, improving some properties such as dimensional stability, resistance to attack by wood decay organisms, and reducing the hygroscopicity. This occurs mainly by the OH groups degradation prese
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/05/2010
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17. Análise comparativa entre vários métodos de quantificação de hemiceluloses da madeira de eucalipto
Pulp hemicelluloses can be extracted with NaOH and quantified by colorimetric and gravimetric techniques. However the most usual methods to measure eucalyptus pulp hemicelluloses have been through the pentosan method or through xylan analyses by GC or HPLC techniques. In this study a comparison was made between the more traditional methods and indirect metho
Química Nova. Publicado em: 2010
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18. Ontogênese, função e evolução das traqueídes vasculares em Cactaceae, tendo como modelo o cacto colunar Pilosocereus aurisetus (Werdern.) Byles &G. D. Rowley / Ontogenesis, function and evolution of wide-band tracheids in Cactaceae: Ontogenesis, function and evolution of wide-band tracheids in Cactaceae: using Pilosocereus aurisetus as a model cactus.
Studies with wide-band tracheids have adressed phylogenetic and functional questions. Although these cells have been described as tracheids, with secondary cell walls thicker than 2µm, their recent register in different tissues of other families has pointed out that this definition may not be well established. The aim of the present study is to understand t
Publicado em: 2010
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19. Modificações da parede celular de frutos do mamoeiro (Carica papaya L.) em diferentes estadios do desenvolvimento / Modifications of the cell wall of fruits of papaya (Carica papaya L.) at various stages of development
The plant cell wall is a unique component of plant tissues and its polysaccharide composition essential to understand food texture and its changes during post-harvestingl especially of climateric fruits, as is the case of papaya. The plant cell wall is composed of three domains: the first is formed by cellulose and hemicelluloses, the second of pectins and t
Publicado em: 2009
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20. Amonização de feno de Coast-cross. / Ammonization in coast-cross hay.
This experiment was accomplished in the Animal Nutrition and Pastures Department in the Institute of Animal Science of the Rural Federal University of Rio de Janeiro. The effects of increasing levels of urea addition were evaluated on the chemical-bromatologic and microbiologic composition of Coast-cross hay. The hay was treated with 5 levels of urea (0, 0,5
Publicado em: 2009
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21. UtilizaÃÃo da serragem de Eucalyptus sp. na preparaÃÃo de carvÃes ativados / Utilization of sawdust of Eucalyptus sp. for activated carbons preparation
The aim of this study was to use the eucalyptus sawdust, waste timber industry, in the preparation of activated carbons (AC) and test them as adsorbents of organic compounds and metal ions. Initially, the Eucalyptus sp sawdust was characterized by chemical analysis like cellulose, lignin, hemicelluloses, ash and extractives content as well as some instrument
Publicado em: 2009
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22. 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
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23. Passion Fruit fiber associated to physical exercises for controlling lipidemy in female rats / Farinha da casca de maracujà associada ao exercÃcio fÃsico no controle da lipidemia de ratas
Aiming to physically and chemically analyze the agroindustrial residue (peel) of three passion fruit species, yellow sweet passion fruit (maracujà amarelo doce â MAD) passiflora alata curtis, yellow sour passion fruit, (amarelo azedo â MAA), passiflora edulis f. flavicarpa, purple sour passion fruit (roxo azedo â MRA), passiflora edulis sims, among these
Publicado em: 2008
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24. Effect of age of the wood of eucalyptus in its chemical and pulpability, and bleachability and properties of the pulp / Efeito da idade da madeira de eucalipto na sua química e polpabilidade, e branqueabilidade e propriedades físicas da polpa
The concern about the quality of the wood that enters a cellulose factory has been focused on many studies, once the productive process and final product are under great influence of the original raw material. Considering the demand for younger trees, the effect of the age of the wood in the chemical constitution and the variables of the process, as well as
Publicado em: 2008