PERCEPÇÃO DO PÚBLICO EM RELAÇÃO A CT&I PELA AVALIAÇÃO DAS CARTAS DE LEITORES

O presente trabalho traz um recorte de cartas publicadas ao longo de cinco semanas em quatro jornais impressos (Folha de S. Paulo, Correio Popular, Gazeta de Piracicaba e Jornal Cidade de Bauru) com conteúdo de ciência, tecnologia e/ou inovação (CT&I). É feita uma análise quali- e quantitativa do conteúdo dessas cartas à luz da análise do discurso e da percepção de CT&I pelo público leitor desses jornais. O porcentual de cartas sobre CT&I em comparação com o total para três dos jornais analisados (3-5%) é semelhante ao identificado como a parcela da população que diz ter experiências concretas de participação nas questões de CT&I (7,3%). Apenas a Gazeta de Piracicaba apresentou índice maior de 35% em situação diferenciada porque 70% das cartas eram exclusivas de um único leitor que é médico. O local de fala de quem escreve para os jornais é prioritariamente o do cientista, pesquisador, especialista ou médico, configurando autoridade ao leitor/escritor da carta

Studies of lignin and polysaccharides recovery from kraft liquor for biotechnological applications

According to the biorefinery concept, this study has the objective of evaluating alternatives for the valorization of all the kraft liquor fractions. This liquor consists mainly in lignin, cellulose and hemicellulose. Currently, cellulose pulp industries recover the cooking chemicals by burning and energy is introduced into the process. Sustainable development guidelines, regarding the costs and wastes reduction and biotechnology principles may present new solutions for the production of valuable products. In this study, two methods for the polysaccharides extraction, in three different pH conditions, are presented. The only difference between these methods is the solvent applied: ethanol and 1,4‐dioxane. All the samples were maintained 24 h at 298 K. After a filtration step, the solid fraction resultant from the ethanol treatment had a carbohydrate content of 40.51%, 44.64% and 49.53%, for pH values of 3, 4 and 6, respectively. The treatment with 1,4‐dioxane, reached the following values: 21.17%, 18.41% and 29.73% for the same pH values. These results were obtained with HPLC analysis after polysaccharides hydrolysis. Three unknown peaks were detected that we considered to be sugar derivative compounds. Thus, the polysaccharides contents, for both treatments, might actually be superior. Concerning to the product purity, the ethanol extraction revealed to be the less efficient. The lignin content in the solid fraction, ranged between 28% and 31%, with 1,4‐dioxane extraction, and between 40% and 50%, with ethanol. The lignin molecular weight was determined with GPC, after and before liquor pH lowering. Thereby, for pH 6, pH 4 and pH 3 the obtained MWs were: 2376 Da, 1477 Da and 3705 Da, respectively. The molecular weight increase may be due to the lignin repolymerization. These results suggest that the polysaccharides recovery and lignin molecular weight may be related. As the molecular weight increases or decreases, the polysaccharides percentage presents the same behavior, regardless of the product purity. The data obtained after FT‐IR analysis suggested that there was no significant modifications on lignin structure. Summarizing, these preliminary results indicate that there is a possibility of recovering the kraft liquor´s polysaccharide while the residual lignin can still be used for burning to energy recovery.Erasmus Mundus ‐ ISAC ProgramFundação para a Ciência e a Tecnologia (FCT)Millipore BrazilConselho Nacional de Desenvolvimento Científico e Tecnológico Brazil - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CNPq‐CAPES

Mass balance of pilot-scale pretreatment of sugarcane bagasse by steam explosion followed by alkaline delignification

Five pilot-scale steam explosion pretreatments of sugarcane bagasse followed by alkaline delignification were explored. The solubilised lignin was precipitated with 98% sulphuric acid. Most of the pentosan (82.6%), and the acetyl group fractions were solubilised during pretreatment, while 90.2% of cellulose and 87.0% lignin were recovered in the solid fraction. Approximately 91% of the lignin and 72.5% of the pentosans contained in the steam-exploded solids were solubilised by delignification, resulting in a pulp with almost 90% of cellulose. The acidification of the black liquors allowed recovery of 48.3% of the lignin contained in the raw material. Around 14% of lignin, 22% of cellulose and 26% of pentosans were lost during the process. In order to increase material recovery, major changes, such as introduction of efficient condensers and the reduction in the number of washing steps, should be done in the process setup. (C) 2012 Elsevier Ltd. All rights reserved.Alexander von Humboldt FoundationConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazi

Obtenção de insumos quimicos e farmaceuticos a partir da lignina hidrolitica de eucalipto

Orientador: Ulf Friedrich SchuchardtDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaMestrad

Oxidação de ligninas e modelos de lignina com oxigenio molecular em meio acido

Orientador: Ulf Friedrich SchuchardtTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaDoutorad

Sugarcane Straw Reinforced Castor Oil Polyurethane Composites: Fiber Characterization and Analysis of Composite Properties

This work was concerned with the development of polyurethane (PU) composites reinforced with cellulose fibers attained from sugarcane straw. For the obtainment of cellulose, sugarcane straw was pretreated and delignified. For the production of the PU, the polyol (castor oil) to diisocyanate mass ratio was 1.5:1.0. Reinforcement of the matrix was done, changing the concentration of cellulose fibers (5%, 10%, 15%, and 20% w/w). The efficiency on the obtainment of cellulose fibers was verified by chemical characterization and the fibers morphological aspects by scanning electron microscopy. The influence of fibers content in the composites was studied by thermal analyses, tensile and moisture absorption tests

Steam explosion pretreatment reproduction and alkaline delignification reactions performed on a pilot scale with sugarcane bagasse for bioethanol production

This work was focused on the steam explosion pretreatment reproduction and alkaline delignification reactions on a pilot scale for the ethanol production, through different varieties of natural sugarcane bagasse, pretreated bagasse and delignified pretreated bagasse (cellulosic pulp). The possible chemical composition differences of the various types of bagasse, as well as the chemical composition variations of the materials in the 20 processes of pretreatment and delignification on the pilot scale were verified. The analytical results of the 20 samples of most diverse varieties and origins of natural sugarcane bagasse considering planting soils, planting periods and weather; show no significant chemical differences. It is evident that only with the chemical composition it is not possible to verify the differences between the varieties of sugarcane bagasses. The research results may offer some evidences of these varieties, but it is not a reliable parameter. The pilot process of steam explosion pretreatment and the alkaline delignification process of pretreated material showed through analytical results a good capacity of reproduction, as the standard differences were below 2.7. The average allowed in the pretreatment and alkaline delignification processes were 66.1 +/- 0.8 and 51.5 +/- 2.6 respectively, ensuring an excellent reproduction capacity of the processes obtained through chemical characterizations. (C) 2011 Elsevier B.V. All rights reserved