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A study of the effects of varying break drafts at the drawing process on the physical properties of Arnel and combed cotton yarnsMarvin, John Henry January 1960 (has links)
No description available.
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The effect of carriers on the flammability of polyester and triacetateStreit, Nadine Joann January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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Chemoenzymatic Synthesis Of Enantiomerically Enriched 2-oxobicyclo[m.1.0]alkan-3-yl Acetate DerivativesAtli, Selin 01 June 2005 (has links) (PDF)
& / #945 / ,& / #946 / -Unsaturated cyclic ketones were selectively oxidized on & / #945 / ' / - positions using Mn(OAc)3 and Pb(OAc)4, respectively. The resultant racemic & / #945 / ' / -acetoxylated substrates were resolved into corresponding enantiomerically enriched & / #945 / ' / -hydroxylated and & / #945 / ' / -acetoxylated compounds via PLE hydrolysis. & / #945 / ' / -Hydroxylated compounds are racemized quickly, so they were acetylated with acetyl chloride and pyridine in situ to give the corresponding & / #945 / ' / -acetoxylated compounds. Resultant & / #945 / ' / -acetoxy & / #945 / ,& / #946 / -unsaturated cyclic ketones reacted with excess amount of diazomethane under the catalsts of Pd(OAc)2 to give the resulting bicyclic diastereomeric products. At the end of the experiment, Enantiomeically enriched 2-oxobicyclo[3.1.0]hexan-3-yl acetate and 2-oxobicyclo[4.1.0]heptan-3-yl acetate were chemoenzymatically synthesized.
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Síntese e caracterização de membranas de triacetato de celulose a partir do aproveitamento do bagaço de cana-de-açúcar para a liberação controlada de drogasRibeiro, Sabrina Dias 26 July 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents a study of the use of sugarcane bagasse as an alternative source of cellulose, for obtaining cellulose triacetate (CTA) and consequently production of membranes for use in controlled release system (CRS) of the drugs naproxen (water insoluble) and doxycycline (water soluble). The sugarcane bagasse was delignified from three successive reflux of a mixture 80/20 (v/v) nitric acid concentrated and ethanol, subsequently treated in NaOH solution. From the analysis of Klason Lignin, noted that in delignified bagasse (DB) there was a reduction in lignin content of 98% compared with gross bagasse. CTA produced presented degree of substitution (DS) 2.80 ± 0.09, what classifies as cellulose triacetate (CTA). The formulations used, CTA/dichloromethane/drug and CTA/dichloromethane/water/drug led to the production of symmetric and asymmetric I membranes, respectively. The formulation with the system solvent dioxane/acetone resulted in asymmetric II membranes with pores in thickness and dense surface, morphologies observed from the analysis of scanning electron microscopy (SEM). The results of the thermal analysis showed that there are interactions between drugs and the CTA. The polymeric matrices showed Swelling index (Si) approximately 12%, a result that will influence on the release kinetics of drugs. The content of naproxen released was 8, 50 and 25% from symmetric, asymmetric I and asymmetric II membranes, respectively. Doxycycline presented release content 14% in experiments with symmetric membranes and 80% with asymmetric I membranes. The study of CRS of drugs showed that membrane morphology has great influence on drugs desorption and the release occurs predominantly by diffusion. / Esse trabalho apresenta um estudo da utilização de bagaço de cana de açúcar como fonte alternativa de celulose, para a obtenção de triacetato de celulose (TAC) e consequentemente produção de membranas para o uso em sistema de liberação controlada (SLC) dos fármacos naproxeno (lipossolúvel) e doxiciclina (hidrossolúvel). O bagaço de cana de açúcar foi deslignificado a partir de três refluxos sucessivos de uma mistura 20/80 (v/v) de ácido nítrico concentrado e etanol hidratado, e posteriormente tratado em solução NaOH. A partir da análise de Lignina Klason, observou se que no bagaço deslignificado (BD) houve uma redução no teor de lignina de 98 % em relação ao bagaço bruto. O TAC produzido apresentou grau de substituição 2,80 ± 0,09, classificando-o como triacetato de celulose (TAC). As formulações utilizadas, TAC/diclorometano/ fármaco e TAC/diclorometano/água/ fármaco levaram à produção de membranas simétricas e assimétricas I, respectivamente. A formulação com o sistema solvente dioxano/acetona resultou em membranas assimétricas II com poros na espessura e superfície mais densa, morfologias observadas a partir das análises de Microscopia Eletrônica de Varredura (MEV). Os resultados da análise térmica mostraram que há interações entre os fármacos e o TAC. As matrizes poliméricas apresentaram Índice de Intumescimento (Ii) de aproximadamente 12 %, resultado que influenciou na cinética de liberação das drogas. O teor do naproxeno liberado foi 8, 50 e 25 % a partir das membranas simétricas, assimétricas I e assimétricas II, respectivamente. A doxiciclina apresentou teor de liberação de 14 % nos experimentos com as membranas simétricas e 80 % com as assimétricas I. O estudo do SLC das drogas mostrou que a morfologia das membranas exerce grande influência na dessorção dos fármacos e a liberação ocorre predominantemente por difusão. / Mestre em Química
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Interfacial Structure of Bilayer Compensation Films Prepared by Direct Coating ProcessYu, Wumin 11 December 2012 (has links)
No description available.
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