Thesis (doctoral)--Ludwig-Maximilians-Universität München, 2005. / Title from PDF title page (viewed on May 10, 2006). Includes articles written with other authors. In abstract, "b̳g̳" in "Kb̳g̳" appears as subscript. Includes bibliographical references.

Lignocellulosic biomass is a potential source of fermentable sugars such as glucose. Enzymatic hydrolysis of cellulose is a viable method of solubilizing the glucose from biomass, but the cellulose fraction of native lignocellulosic material is shielded from enzymatic attack by the lignin-hemicellulose matrix surrounding it. Pretreating lignocellulosic biomass with dilute sulfuric acid at high temperatures solubilizes hemicellulose, rendering the cellulose fraction more susceptible to enzymatic hydrolysis. Evaluation of dilute-acid, high-temperature pretreatments depends on polysaccharide analysis of the two fractions resulting from a pretreatment, prehydrolyzed solids(PHS) and prehydrolyzate liquid(PH). The polysaccharide analysis is based on a method described by the National Renewable Energy Laboratory and involves a two-stage sulfuric acid hydrolysis followed by HPLC quantification using ion-moderated partition chromatography and refractive index detection. The subject of this thesis is identifying and quantifying the sources of error associated with the polysaccharide analysis and the error associated with the evaluation of the effects of pretreatment on the polysaccharide fractions of switchgrass and poplar. This was addressed by conducting replicate polysaccharide analyses on single samples of native biomass, PHS, and PH. The variability associated with these measurements was compared to the variability associated with replicate analyses of identically pretreated biomass. It was found that the use of sugar standards to correct for sugar destroyed during the analysis adds error and most likely overestimates the amount of sugar from biomass actually destroyed. It is evident that assuming a volume after neutralization of the hydrolyzed biomass sample is more reproducible than measuring the volume. When using a batch-type reactor and the temperature and acid parameters used in this study,140°C-180°C/ 0.6-1.2 % sulfuric acid (w/w), it is evident that the major source of error in evaluating pretreatment conditions is the pretreatment itself, not the analysis. / Graduation date: 1995

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science 17th August 2015 in Johannesburg, South Africa / Ecosystem services provide a vital lifeline to millions of people living in rural areas. The poorest people in these areas depend upon the natural resource base in their surroundings to provide these services. With growing populations in rural areas of South Africa, the natural resource base is under considerable pressure; however, uncovering the dynamics of vegetation in these systems has proven difficult. While much attention has been given to savanna ecology, long term studies on the patterns and drivers of woody biomass are few. We used 65 years of aerial imagery (from 1944 to 2009) over 31 953 ha of rural savanna in a communal rangeland in South Africa to determine the abundance of woody canopy cover. This data were captured at hectare resolution, giving a fine enough level of detail for local level analysis. We also captured data for five potential drivers for change at this resolution, in order to analyse these drivers for their relative importance in determining woody canopy cover throughout the study period. Surprisingly, while individual sites showed varied trends in the amounts of woody canopy cover through time, when pooled across all sites the total woody canopy cover increased over the 65 year period. Disturbance gradients were found around some of the villages, but only in 2009, suggesting that the drivers of disturbance gradients in these systems may have only operated sufficiently to produce disturbance gradients in recent years. A hot spot analysis (hot spots indicate cells that have similarly high values beyond what would be expected in a random distribution, with cold spots indicating the inverse) revealed an increase in both hot and cold spots through time, but with a low persistence of both through time. High canopy cover cells are presumed to be the result of bush encroachment, while low canopy cover cells are presumed to be the result of harvesting of trees for fuelwood or clearing for fields. The low persistence of hot and cold spots points to a system in continual change, with patches of hot and cold spots appearing and disappearing, and therefore drivers of change operating in short periods of time. MAP (Mean Annual Precipitation), and not an anthropogenic driver, was found to be the most important driver for woody canopy cover throughout the study period, with MAP up to 670 mm having a predictable pattern of hot and cold spots through time. Higher MAP was shown to have a non-linear and unpredictable pattern of hot and cold spots through time, indicating that low precipitation may produce a system where woody canopy cover is less influenced by other drivers and is more stable when acted upon by other drivers. This research demonstrates the value of a long term dataset, and the applicability of our methods for monitoring woody canopy cover. As such, it may well serve as a baseline for woody canopy cover in communal savanna rangeland systems, with the methodology employed here suitable for an early warning detection system for sudden changes in the woody canopy cover.

Made available in DSpace on 2014-06-11T19:22:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-13Bitstream added on 2014-06-13T18:07:53Z : No. of bitstreams: 1 roviero_jp_me_jabo.pdf: 697436 bytes, checksum: 4d7519dfd7c6320838eff351b784d161 (MD5) / A utilização de diferentes biomassas vegetais como fonte de energia renovável deve contribuir para a redução do uso de combustíveis fósseis, minimizando impactos negativos ao meio ambiente. Como resultado direto da colheita mecanizada da cana, tem-se o aumento de ponteiros e palha nos canaviais, insumo de grande potencial energético que podem ser utilizados para a produção do etanol de segunda geração, aumentando a produção anual de etanol sem acréscimos em áreas de plantio. A hidrólise deste material, torna disponível os açúcares constituintes das frações celulósicas e hemicelulósicas e deve passar por um processo de destoxificação para redução do teor de inibidores provenientes da etapa de hidrólise. Neste estudo objetivou-se avaliar o mosto de hidrolisado hemicelulósico de folhas e ponteiros de cana, em comparação com mosto de caldo de cana, fermentado por leveduras que desdobram hexoses e pentoses para produção de etanol de segunda geração. Os mostos foram compostos por caldo de cana, hidrolisado hemicelulósico de folhas e pontas de cana e pela mistura destes dois mostos (50%). O processo fermentativo foi realizado em escala laboratorial empregando-se as estirpes J10 e FT858 de leveduras e a mistura destas (50%). Foram feitas análises de viabilidade celular e índice de brotamentos e avaliadas as concentrações dos açúcares e produção de etanol. A viabilidade celular, viabilidade de brotos e o brotamento sempre foram maiores em mosto de caldo de cana. Os valores mais elevados entre as leveduras foram obtidos pela linhagem J10. O processo de destoxificação utilizado promoveu uma remoção parcial de ácidos e composto fenólicos. A utilização de coculturas de microrganismos foi mais eficiente na produção de etanol em relação as culturas individuais. O hridrolisado hemicelulósico apresentou baixa eficiência na produção de etanol. / The use of different plant biomass as a renewable energy source should contribute to reducing the use of fossil fuels, minimizing negative impacts to the environment. As a direct result of mechanical harvesting of sugarcane has increased pointers and straw in the cane fields, input of large energy potential that can be used for the production of second generation ethanol, increasing the annual production of ethanol without increases in areas planting. Hydrolysis of this material makes available the sugars constituting the cellulose and hemicellulose fractions and must undergo a detoxification process for reducing the content of inhibitors from the hydrolysis step. This study aimed to evaluate the wort hemicellulosic hydrolyzate pointers leaves and cane, compared with mash of sugar cane juice, fermented by yeasts that unfold hexoses and pentoses for production of second generation ethanol. The musts were composed of sugarcane juice, hemicellulosic hydrolyzate leaves and cane tips and the mixture of these two musts (50%). The fermentation was performed in laboratory scale employing strains J10 and FT858 yeast and mixing these (50%). Analyzes were performed for cell viability and budding index and evaluated the concentrations of sugars and ethanol production. Cell viability, feasibility and budding shoots were always higher in mash of sugar cane juice. The highest values were obtained between the yeast strain J10. The detoxification process used promoted partial removal of acids and phenolic compounds. The use of cocultures of microorganisms was more efficient in producing ethanol in relation to individual cultures. The hemicellulosic hridrolisado showed low efficiency in ethanol production.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Douglas W. Tallamy, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 52-57). Also available on the World Wide Web.

Made available in DSpace on 2014-06-11T19:35:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-12Bitstream added on 2014-06-13T20:07:25Z : No. of bitstreams: 1 000759124.pdf: 1601196 bytes, checksum: e9bfb948d9cb87bf323723298fc5f1e4 (MD5) / A crescente demanda por recursos energéticos renováveis tem impulsionado o desenvolvimento de plantios florestais com maior eficiência na produção de madeira com qualidade para este fim, mas com viabilidade econômica e com mínimos danos a sustentabilidade dos sítios de produção, fatores que objetivaram e justificaram o presente trabalho com Eucalyptus grandis x E. urophylla em sistemas de curta rotação. O experimento foi instalado em 2008, nos espaçamentos de 2,8x0,5 m, 2,8x1,0 m, 2,8x1,5 m, 2,8x2,0 m e 2,8x2,5 m, com três níveis de adubação. A aplicação de adubos foi NPK 6-30-6 no plantio nas doses de 70, 140 e 280 g.planta-1 e na cobertura foi de NPK 20-0-20 nas doses de 25, 50 e 100 g.planta-1 aos 60 dias, 35, 70 e 140 g.planta-1 aos 140 dias e 50, 100 e 200 g.planta-1 aos 360 dias após o plantio. Árvores amostra foram colhidas em três ocasiões, aos 18 meses, 24 meses e 30 meses para avaliações de volume, massa seca de madeira e atributos energéticos produtividade energética, acúmulo de cinzas, lignina e extrativos na madeira e exportação de nutrientes. Baseando-se no estudo de caso dos custos operacionais da empresa para a produção de briquetes, foram simulados os indicadores econômicos valor presente líquido, razão beneficio custo e custo médio de produção. A maior produção de volume de madeira com casca ocorreu aos 30 meses, no espaçamento de 2,8x0,5 m e 2,8x1,0 m, considerando que nesta idade a média estimada foi de 167 m³.ha-1. Com relação a massa seca de madeira, médias de 70 e 90 t.ha-1 foram encontradas nos espaçamentos mais adensados e com maior aplicação de adubo. A produtividade energética foi maior em espaçamentos mais adensados,... / The growing demand for renewable energy resources has driven the development of forest plantations with greater efficiency in the production of quality wood for this purpose, but with economic viability and sustainability with minimal damage to the sites of production, factors that objected and justified the present work. The experiment was installed in 2008 on a farm in which it produces wood briquettes, the spacing of 2.8x0.5 m, 2.8x1.0 m, 2.8x1.5 m, 2.8x2.0 m and 2.8x2.5 m, with three levels of fertilization. The application of fertilizers was NPK 30-6 at planting at doses of 70, 140 and 280 g/plant and the coverage was NPK 20-0-20 at doses of 25, 50 and 100 g/plant at 60 days, 35, 70 and 140 g/plant at 140 days and 50, 100 and 200 g/plant at 360 days after planting. Sample trees were harvested on three occasions, at 18 months, 24 months and 30 months for evaluation of volume, dry mass and the energy attributes energy productivity, accumulation of ash, lignin and extractives in wood and XII nutrient export. Based on the case study of the company's operating costs for the production of briquettes, economic indicators were simulated net present value, benefit cost ratio and average cost of production. The largest production volume of wood with bark occurred at 30 months, spaced 2.8x0.5 m and 2.8x1.0 m, whereas this age the estimated average was 167 m³/ha. With respect to dry mass, averaging 70 and 90 t/ha were found in denser spacing and greater application of fertilizer. The productivity was higher in energy narrower spacing plant, 2.8x0.5 m and 2.8x1.0 m, especially when obtained at 30 months in the case of trees planting between 0.5 m of space reached average 40 tep/ha. Already compounds lignin, extractives and ash were found in greater accumulation in trees harvested wider spacing, and the ash content of around 1% due to the presence of bark in the sample...

Orientador: Saulo Philipe Sebastião Guerra / Banca: Maura Seiko Tsutsui Esperancini / Banca: Kleber Pereira Lanças / Banca: Gustavo Kimura Montanha / Banca: Jorge Mangolini Neves / Resumo: A cana-de-açúcar é plantada em 23 estados brasileiros totalizando mais de 10,2 milhões de hectares, e para cada hectare existem em torno de 10 toneladas de palhiço (bs), biomassa resultante da colheita mecanizada. O aproveitamento deste material é importante economicamente devido à quantidade disponível, diversificação da matriz energética, geração de energia elétrica, e produção de etanol e de papel. Devido à entressafra na produção de cana-de-açúcar, é necessário a estocagem dos fardos produzidos em grandes pilhas por até um ano, sendo a forma mais adequada de armazenamento de fardos de palhiço ainda desconhecida, o que proporcionou incêndios de grandes proporções em algumas usinas. Com o objetivo de proporcionar técnicas mais eficientes no armazenamento de palhiço, foi avaliada, a partir de técnicas geoestatísticas, a distribuição da umidade no interior de pilhas armazenadas em campo, sem cobertura, em duas densidades de enfardamento, três quantidades de água acumuladas de precipitações, e à picagem ou não do palhiço antecedendo o enfardamento. Também, foi analisada a viabilidade econômica entre duas rotas de aproveitamento do palhiço, desde o campo até a indústria, diferindo-se pelo momento em que é realizada a trituração do palhiço. Em todos os tratamentos avaliados foi observada a existência de dependência espacial, sendo possível a utilização de métodos geoestatísticos para análise. O modelo esférico foi o mais adequado para descrever o comportamento da umidade no inte... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sugarcane is planted in 23 Brazilian states totalling more than 10.2 million hectares, and for each hectare there are around 10 tons of straw (db), biomass resulting from mechanized harvesting. The use of this material is economically important due to the quantity available, energy matrix diversification, electric power generation, and ethanol and paper production. Due to the off-season in the production of sugarcane, it is necessary to store the bales produced in large piles for up to one year, being the most adequate form of storage of bales still unknown, which caused fires of great proportions in some plants In order to provide more efficient techniques for the storage of straw, we evaluated the distribution of moisture inside piles stored in the field, without cover, in two baling densities, three accumulated amounts of precipitation, and to the crushing or not of the straw before the baling. Also, the economic viability between two routes of exploitation of the straw was analyzed, from the field to the industry, differing by the moment in which the straw is crushed. In all the evaluated treatments the existence of spatial dependence was observed, being possible the use of geostatistical methods for analysis. The spherical model was the most appropriate to describe the behavior of moisture inside the cells. The crushing of straw affected the distribution of moisture, as well as the density and amount of precipitation accumulated. For short storage periods, bales of crush... (Complete abstract click electronic access below) / Doutor

Título da capa: Qualidade energética da madeira de eucalipto em função do espaçamento, da adubação e da idade conduzida no sistema de curta rotação / / Orientador: Kléber Pereira Lanças / Coorientador: Saulo Philipe Sebastião Guerra / Banca: Fabio Minoruy Yamaji / Banca: José Mauro Santana da Silva / Banca: Franciane Andrade de Pádua / Banca: Claudio Angeli Sansigolo / Resumo: A crescente demanda por recursos energéticos renováveis tem impulsionado o desenvolvimento de plantios florestais com maior eficiência na produção de madeira com qualidade para este fim, mas com viabilidade econômica e com mínimos danos a sustentabilidade dos sítios de produção, fatores que objetivaram e justificaram o presente trabalho com Eucalyptus grandis x E. urophylla em sistemas de curta rotação. O experimento foi instalado em 2008, nos espaçamentos de 2,8x0,5 m, 2,8x1,0 m, 2,8x1,5 m, 2,8x2,0 m e 2,8x2,5 m, com três níveis de adubação. A aplicação de adubos foi NPK 6-30-6 no plantio nas doses de 70, 140 e 280 g.planta-1 e na cobertura foi de NPK 20-0-20 nas doses de 25, 50 e 100 g.planta-1 aos 60 dias, 35, 70 e 140 g.planta-1 aos 140 dias e 50, 100 e 200 g.planta-1 aos 360 dias após o plantio. Árvores amostra foram colhidas em três ocasiões, aos 18 meses, 24 meses e 30 meses para avaliações de volume, massa seca de madeira e atributos energéticos produtividade energética, acúmulo de cinzas, lignina e extrativos na madeira e exportação de nutrientes. Baseando-se no estudo de caso dos custos operacionais da empresa para a produção de briquetes, foram simulados os indicadores econômicos valor presente líquido, razão beneficio custo e custo médio de produção. A maior produção de volume de madeira com casca ocorreu aos 30 meses, no espaçamento de 2,8x0,5 m e 2,8x1,0 m, considerando que nesta idade a média estimada foi de 167 m³.ha-1. Com relação a massa seca de madeira, médias de 70 e 90 t.ha-1 foram encontradas nos espaçamentos mais adensados e com maior aplicação de adubo. A produtividade energética foi maior em espaçamentos mais adensados,... / Abstract: The growing demand for renewable energy resources has driven the development of forest plantations with greater efficiency in the production of quality wood for this purpose, but with economic viability and sustainability with minimal damage to the sites of production, factors that objected and justified the present work. The experiment was installed in 2008 on a farm in which it produces wood briquettes, the spacing of 2.8x0.5 m, 2.8x1.0 m, 2.8x1.5 m, 2.8x2.0 m and 2.8x2.5 m, with three levels of fertilization. The application of fertilizers was NPK 30-6 at planting at doses of 70, 140 and 280 g/plant and the coverage was NPK 20-0-20 at doses of 25, 50 and 100 g/plant at 60 days, 35, 70 and 140 g/plant at 140 days and 50, 100 and 200 g/plant at 360 days after planting. Sample trees were harvested on three occasions, at 18 months, 24 months and 30 months for evaluation of volume, dry mass and the energy attributes energy productivity, accumulation of ash, lignin and extractives in wood and XII nutrient export. Based on the case study of the company's operating costs for the production of briquettes, economic indicators were simulated net present value, benefit cost ratio and average cost of production. The largest production volume of wood with bark occurred at 30 months, spaced 2.8x0.5 m and 2.8x1.0 m, whereas this age the estimated average was 167 m³/ha. With respect to dry mass, averaging 70 and 90 t/ha were found in denser spacing and greater application of fertilizer. The productivity was higher in energy narrower spacing plant, 2.8x0.5 m and 2.8x1.0 m, especially when obtained at 30 months in the case of trees planting between 0.5 m of space reached average 40 tep/ha. Already compounds lignin, extractives and ash were found in greater accumulation in trees harvested wider spacing, and the ash content of around 1% due to the presence of bark in the sample... / Doutor

Orientador: Márcia Justino Rossini Mutton / Banca: Flávia Cecílio Ribeiro / Banca: Clóvis Parazzi / Resumo: A utilização de diferentes biomassas vegetais como fonte de energia renovável deve contribuir para a redução do uso de combustíveis fósseis, minimizando impactos negativos ao meio ambiente. Como resultado direto da colheita mecanizada da cana, tem-se o aumento de ponteiros e palha nos canaviais, insumo de grande potencial energético que podem ser utilizados para a produção do etanol de segunda geração, aumentando a produção anual de etanol sem acréscimos em áreas de plantio. A hidrólise deste material, torna disponível os açúcares constituintes das frações celulósicas e hemicelulósicas e deve passar por um processo de destoxificação para redução do teor de inibidores provenientes da etapa de hidrólise. Neste estudo objetivou-se avaliar o mosto de hidrolisado hemicelulósico de folhas e ponteiros de cana, em comparação com mosto de caldo de cana, fermentado por leveduras que desdobram hexoses e pentoses para produção de etanol de segunda geração. Os mostos foram compostos por caldo de cana, hidrolisado hemicelulósico de folhas e pontas de cana e pela mistura destes dois mostos (50%). O processo fermentativo foi realizado em escala laboratorial empregando-se as estirpes J10 e FT858 de leveduras e a mistura destas (50%). Foram feitas análises de viabilidade celular e índice de brotamentos e avaliadas as concentrações dos açúcares e produção de etanol. A viabilidade celular, viabilidade de brotos e o brotamento sempre foram maiores em mosto de caldo de cana. Os valores mais elevados entre as leveduras foram obtidos pela linhagem J10. O processo de destoxificação utilizado promoveu uma remoção parcial de ácidos e composto fenólicos. A utilização de coculturas de microrganismos foi mais eficiente na produção de etanol em relação as culturas individuais. O hridrolisado hemicelulósico apresentou baixa eficiência na produção de etanol. / Abstract: The use of different plant biomass as a renewable energy source should contribute to reducing the use of fossil fuels, minimizing negative impacts to the environment. As a direct result of mechanical harvesting of sugarcane has increased pointers and straw in the cane fields, input of large energy potential that can be used for the production of second generation ethanol, increasing the annual production of ethanol without increases in areas planting. Hydrolysis of this material makes available the sugars constituting the cellulose and hemicellulose fractions and must undergo a detoxification process for reducing the content of inhibitors from the hydrolysis step. This study aimed to evaluate the wort hemicellulosic hydrolyzate pointers leaves and cane, compared with mash of sugar cane juice, fermented by yeasts that unfold hexoses and pentoses for production of second generation ethanol. The musts were composed of sugarcane juice, hemicellulosic hydrolyzate leaves and cane tips and the mixture of these two musts (50%). The fermentation was performed in laboratory scale employing strains J10 and FT858 yeast and mixing these (50%). Analyzes were performed for cell viability and budding index and evaluated the concentrations of sugars and ethanol production. Cell viability, feasibility and budding shoots were always higher in mash of sugar cane juice. The highest values were obtained between the yeast strain J10. The detoxification process used promoted partial removal of acids and phenolic compounds. The use of cocultures of microorganisms was more efficient in producing ethanol in relation to individual cultures. The hemicellulosic hridrolisado showed low efficiency in ethanol production. / Mestre