Inbjudningsskrift--Lund. / Paged continuously.

Thesis (Ph. D.)--Catholic University of America. / Bibliography: p. 178.

No description available.

Inaugural dissertation (Ph. D.)--Friedrich-Wilhelms-Universität zu Berlin, 1932. / Cover title. Bibliography : p.[53]

Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999. / Includes bibliographical references (leaves 103-117).

Orientador: Michel Brienzo / Banca: Sidnei Emilio Bordignon Junior / Banca: Luciana Fontes Coelho / Resumo: O bagaço de cana-de-açúcar é um subproduto da indústria sucroalcooleira, majoritariamente usado para a cogeração de energia térmica e elétrica, através de sua combustão em caldeiras. Em função da sua composição em carboidratos vem sendo estudado na conversão em biocombustíveis. Porém, a recalcitrância da matriz lignocelulósica dificulta desestruturação do material, com baixa acessibilidade à celulose, influenciando na sacarificação enzimática. Neste contexto, o objetivo deste trabalho foi avaliar o efeito do pré-tratamento ácido diluído (10 %, m/m, 121 °C/30 min) em diferentes granulometrias, 16, 24, 35, 60 mesh e fundo de bagaço e fração externa (contendo epiderme) do colmo de cana-de-açúcar. Cada biomassa de cana-de-açúcar, em diferentes granulometrias, passou pelo pré-tratamento ácido diluído (10 %, m/m, 121° C/30 min). As amostras foram caracterizadas quanto ao seu conteúdo de celulose, hemicelulose e lignina. A área superficial de lignina foi determinada com a adsorção do corante catiônico Azure B em solução de 0,1 g.L-1. A determinação de acessibilidade à celulose foi realizada com corantes Direct Orange (superfície específica externa) e Direct Blue (superfície específica interna). A hidrólise enzimática (15 FPU.g-1 durante 24 h - Cellic Cetec 2 - Novozymes) foi aplicada nos materiais para avaliar o rendimento em glicose. Para o material retido na peneira de abertura 16 mesh, maior tamanho de partículas, a massa recuperada de bagaço foi de 59,81 % e no fundo, menor tama... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sugarcane bagasse is a by-product of the sugar and alcohol industry, mostly used for cogeneration of thermal and electric energy, through its combustion in boilers. Due to its composition in carbohydrates has been studied in the conversion to biofuels. However, the recalcitrance of the lignocellulosic matrix makes it difficult to disintegrate the material, with low accessibility to the cellulose, influencing the enzymatic saccharification. In this context, the objective of this work was to evaluate the effect of diluted acid pretreatment (10 %, m/m, 121 °C / 30 min) in different granulometries, 16, 24, 35, 60 mesh and background bagasse and fraction (containing epidermis) from the sugar cane stalk. Each biomass of sugarcane, in different granulometries, underwent the pre-treatments diluted acid (10 %, m/m, 121 °C / 30 min). The samples were characterized for their content of cellulose, hemicellulose and lignin. The surface area of lignin was determined with the adsorption of the cationic dye Azure B in solution of 0.1 g.L-1. The determination of accessibility to the cellulose was performed with Direct Orange (specific external surface) and Direct Blue (specific internal surface) dyes. Enzymatic hydrolysis (15 FPU.g-1 for 24 h - Cellic Cetec 2 - Novozymes) was applied to the materials to evaluate glucose yield. For the material retained in the 16 mesh aperture sieve, larger particle size, the recovered mass of bagasse was 59.81 % and in the bottom, smaller particle size was 53... (Complete abstract click electronic access below) / Mestre

Thesis--Universiteit van Amsterdam, 1920. / Includes bibliographical references (p. 103-104).

This study examines the environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the karoo. This is the first study of its kind on oldman saltbush and serves as an important scoping exercise in assessing the impact of saltbush on its surrounds and in identifying additional aspects which require investigation. The environmental parameters investigated include microclimatic effects, soil induced changes, salinity effects on the germination of selected karoo species and compositional changes in the indigenous plant community within a saltbush plantation. When compared to indigenous karoo plant species oldman saltbush is found to ameliorate soil temperatures and increase surface soil salinity (specifically sodium chloride), on an individual plant basis. Salinity is shown to have a differential effect on the germination of selected karoo shrubs. The indigenous plant community within a forty year old saltbush plantation is impoverished with both density of individuals and species richness being markedly reduced. Saltbush is identified as an unsuitable nurse plant for the majority of karoo shrubs. Farm size in relation to both actual and intended area established to saltbush is considered. The area of saltbush already established in the karoo is considered too insignificant to have any wide socio-economic impact. Farmers who intend planting large areas of their farms to saltbush are in the minority. It is those farmers who already have some saltbush planted, who intend planting more. Ecologically based management guidelines are presented, suggesting practices which minimize the detrimental effects of saltbush on soil salinity and the indigenous plant community. These guidelines are practical and in keeping with the overall objectives of optimum resource utilisation and the national grazing strategy for South Africa.

This study examines the environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the karoo. This is the first study of its kind on oldman saltbush and serves as an important scoping exercise in assessing the impact of saltbush on its surrounds and in identifying additional aspects which require investigation. The environmental parameters investigated include microclimatic effects, soil induced changes, salinity effects on the germination of selected karoo species and compositional changes in the indigenous plant community within a saltbush plantation. When compared to indigenous karoo plant species oldman saltbush is found to ameliorate soil temperatures and increase surface soil salinity (specifically sodium chloride), on an individual plant basis. Salinity is shown to have a differential effect on the germination of selected karoo shrubs. The indigenous plant community within a forty year old saltbush plantation is impoverished with both density of individuals and species richness being markedly reduced. Saltbush is identified as an unsuitable nurse plant for the majority of karoo shrubs. Farm size in relation to both actual and intended area established to saltbush is considered. The area of saltbush already established in the karoo is considered too insignificant to have any wide socio-economic impact. Farmers who intend planting large areas of their farms to saltbush are in the minority. It is those farmers who already have some saltbush planted, who intend planting more. Ecologically based management guidelines are presented, suggesting practices which minimize the detrimental effects of saltbush on soil salinity and the indigenous plant community. These guidelines are practical and in keeping with the overall objectives of optimum resource utilisation and the national grazing strategy for South Africa.

Título original: Influência da granulometria do bagaço de cana-de-açúcar na solubilização de hemicelulose em meio ácido e alcalino / Orientador: Michel Brienzo / Banca: Lidyane Aline de Freita / Banca: Eleonora Cano de Carmona / Resumo: A grande capacidade da agricultura sucroalcooleira, aliada às suas dimensões continentais, faz do Brasil o maior produtor de cana-de-açúcar do mundo. O bagaço desta matéria-prima é um material lignocelulósico, remanescente da moagem dos seus colmos, é composto principalmente por celulose, hemicelulose e lignina, numa estrutura vegetal organizada que deve ser desestruturada mediante pré-tratamentos para disponibilizar a fração polissacarídica (celulose e hemicelulose). Objetivou-se com a presente pesquisa determinar a influência da granulometria do bagaço de cana-de-açúcar na extração/solubilização de hemicelulose na forma de polissacarídeo (macromolécula) e monossacarídeo (xilose). A extração da hemicelulose macromolecular foi realizada em condições otimizadas para bagaço de cana-de-açúcar, 6 % H2O2 m/v a 25 °C durante 4 h, utilizando bagaço selecionado em peneiras de 16, 30, 40, 50 mesh e base (material que passou pela peneira de 50 mesh). Para extração de hemicelulose na forma monomérica foi utilizado um pré-tratamento com ácido sulfúrico diluído 20 % (m/m), sendo que as amostras foram autoclavadas a 121 ºC por 1 h; a xilose no filtrado foi quantificado por HPLC. Foi realizada também a condutividade, determinação do teor de cinzas totais, solubilidade da hemicelulose. Os resíduos sólidos dos pré-tratamentos foram submetidos a hidrólise enzimática (12 FPU/g - Cellic Ctec) para determinação do rendimento em glicose. O bagaço in natura apresentou conteúdo de glucana de 42,25 %... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The great capacity of sugar-alcohol agriculture, combined with its continental dimensions, makes Brazil the largest producer of sugar cane in the world. The bagasse of this raw material is a lignocellulosic material, reminiscent of the milling of its stems, is composed mainly of cellulose, hemicellulose and lignin, in an organized vegetable structure that must be destructured by means of pre-treatments to provide the polysaccharide fraction (cellulose and hemicellulose). The objective of this research was to determine the influence of sugarcane bagasse granulometry on the extraction/solubilization of hemicellulose in the form of polysaccharide (macromolecule) and monosaccharide (xylose). Macromolecular hemicellulose extraction was performed under optimized conditions for sugarcane bagasse, 6 % H2O2 m / v at 25 °C for 4 h, using bagasse selected in 16, 30, 40, 50 mesh sieves and base (material which passed through the 50 mesh screen). For the extraction of hemicellulose in the monomeric form, a pretreatment with sulfuric acid diluted 20 % (m/m) was used, and the samples were autoclaved at 121 ºC for 1 h; the xylose in the filtrate was quantified by HPLC. Conductivity, determination of total ash content and solubility of hemicellulose were also performed. The solid residues of the pre-treatments were submitted to enzymatic hydrolysis (12 FPU/g - Cellic Ctec) to determine the glucose yield. The bagasse in natura had glucan content of 42.25 %, arabinana of 2.62 %, xylan of 25.39 ... (Complete abstract click electronic access below) / Mestre