The objectives of our study were to determine the potential of 1H MRS in detecting (1) early colonic inflammation, (2) effects of various fatty acids on normal colon and (3) their effects on IBD. Sprague dawley rat fed with 2% carrageenan was used as a model of IBD. Flaxseed oil served as ω-3, corn oil as ω-6 and beef tallow as saturated fatty acid sources. Control group animals were fed 5% corn oil, whereas, those in high-fat diet groups received an additional 7% of the respective fatty acids. After 2 weeks, 1H MRS and histology were conducted on excised colonic mucosa. Statistical classification strategy (SCS) used for analyzing 1H MRS data achieved an accuracy of 82 % in stage 1, 90-100% in stage 2 and 96-100% in stage 3. This implies that 1H MRS is a sensitive tool to diagnose early IBD and the effects of dietary fat on IBD.

The objectives of our study were to determine the potential of 1H MRS in detecting (1) early colonic inflammation, (2) effects of various fatty acids on normal colon and (3) their effects on IBD. Sprague dawley rat fed with 2% carrageenan was used as a model of IBD. Flaxseed oil served as ω-3, corn oil as ω-6 and beef tallow as saturated fatty acid sources. Control group animals were fed 5% corn oil, whereas, those in high-fat diet groups received an additional 7% of the respective fatty acids. After 2 weeks, 1H MRS and histology were conducted on excised colonic mucosa. Statistical classification strategy (SCS) used for analyzing 1H MRS data achieved an accuracy of 82 % in stage 1, 90-100% in stage 2 and 96-100% in stage 3. This implies that 1H MRS is a sensitive tool to diagnose early IBD and the effects of dietary fat on IBD.

The renewed interest in energy for biomass is supported by the need for different energy sources and the need to protect the environment. Recently, because of increases in crude oil prices, limited resources of fossil oil and environmental concerns there has been renewed focus on vegetable oils and animal fats to make a biodiesel fuel. What is known as biodiesel (methyl or ethyl esters) is a vegetable oil or animal fat chemically treated to replace traditional diesel fuel. Performance parameters and exhaust emissions of a diesel engine fuelled with sunflower and beef tallow ethyl esters and a blend of ethyl and methyl esters, subjected to pre-heating at two temperatures ranges, namely T55 (50 to 60ºC) and T75 (70 to 80ºC), in order to lower its viscosities, have been investigated. Tests were carried out at full load conditions in a four cylinders, four-stroke indirect injection diesel engine. Engine tests, short-term, were conducted at a range speed from 1900 to 4400 rpm. The injection timing was retarded from the manufacturer s recommended setting. The tests were carried out using the same engine and test procedures so that comparative assessments may be made. The tests data were used for evaluating the brake power, exhaust gas temperatures, specific fuel consumption and gaseous emissions. The analysis of the results determined that the level of pre-heating have influence on the performance for used esters. The tests performed at T55 showed the best values of torque (N.m), power (kW) and specific fuel consumption (g.kW-1.h-1) that the tests performed at T75. The bests experiments results were obtained with sunflower ethyl ester and the blend containing 50,0% sunflower ethyl ester and 50,0% beef tallow methyl ester, at -2º BTDC and T55 temperature range. The findings showed that, by using biodiesel, harmful emissions (CO, HC and NOx) can be reduced to some extent of B2 by adjusting the injection pump timing properly and pre-heating of fuel. / O renovado interesse por energia da biomassa é apoiado na necessidade de fontes alternativas de energia e de proteção ambiental. Recentemente, devido ao aumento dos preços do óleo cru, a limitação de seus recursos e as questões relacionadas ao ambiente, um renovado foco passou a existir sobre os óleos vegetais e gorduras animais para produção de um biodiesel combustível. O que é conhecido como biodiesel (éster metílico ou etílico) é um óleo vegetal ou gordura animal tratado quimicamente para substituir o combustível diesel tradicional. Parâmetros de desempenho e emissões de exaustão foram investigados para um motor diesel alimentado com ésteres etílicos de óleo de girassol e de sebo bovino e por uma mistura composta pelo éster etílico de óleo de girassol e pelo metílico de sebo bovino numa proporção volumétrica igual (50,0%+50,0%). Os ésteres estavam sujeitos ao pré-aquecimento segundo duas faixas de temperaturas, chamadas de T55 (50 a 60ºC) e T75 (70 a 80ºC), como forma de redução da viscosidade. Os testes foram conduzidos sob condição de carga máxima em um motor diesel de quatro cilindros, quatro tempos e de injeção indireta de combustível. Os ensaios de curta duração foram efetuados em uma faixa de rotações compreendida entre 1900 e 4400 rpm. O ponto de avanço de injeção foi atrasado em relação ao ponto original recomendado pelo fabricante. Os testes foram conduzidos utilizando o mesmo motor e os mesmos procedimentos de testes para permitir a comparação dos valores obtidos. Nos ensaios foram obtidos os valores de potência, torque, consumo específico de combustível e gases de exaustão. A análise dos resultados indica que o nível de pré-aquecimento tem influência sobre o desempenho dos ésteres utilizados. Os ensaios conduzidos à T55 mostraram melhores valores para torque (N.m), potência (kW) e consumo específico de combustível (g.kW-1.h-1) que os testes executados à T75. Os melhores resultados do experimento foram obtidos pelo éster etílico de girassol e pela mistura contendo 50,0% de éster etílico de girassol e 50% de éster metílico de sebo bovino, sob 2º (P2) de atraso no ponto de injeção e aquecidos na faixa de temperaturas de T55. Os resultados indicam que, pelo uso do biodiesel, as emissões prejudiciais (CO, HC e NOx) podem ser reduzidas aos mesmos níveis do B2 através do ajuste apropriado do ponto de avanço da injeção e o pré-aquecimento do combustível.

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Made available in DSpace on 2014-12-17T15:42:13Z (GMT). No. of bitstreams: 1 PauloRP_TESE.pdf: 5067014 bytes, checksum: b7746014c5447355f701f5568c4dabae (MD5) Previous issue date: 2011-06-28 / Biodiesel production has increased over the last decade because of the benefits associated with this fuel, including renewability, domestic feedstock, lower toxicity, and biodegradability. From 2008, the use of beef tallow as a feedstock for biodiesel production in Brazil has increased in significance, representing the second largest source of biodiesel, after soybeans. However, the performance of biodiesel in cold weather conditions is worse than diesel because of deposition of insoluble at low temperatures, accelerating the plugging of fuel filters and injectors of the vehicle engine. Studies have been conducted on beef tallow biodiesel, mostly related to the properties of thermal and oxidative stability. However, few studies have described the nature of the precipitate formed and its influence on product quality. Research suggests that the cause of deposition is related to the nature of saturated esters and monoacylglycerols as inducing agents. This study monitored the levels of mono-, diand triacylglycerols, the oxidation stability and the cold filter plugging point (CFPP) in beef tallow biodiesel samples from two commercial producers in Brazil for a period of twelve months. Filtered precipitates were analyzed by comparative techniques of GCFID, HPLC-UV/VIS, HPLC-MS-IT-TOF and TG to verify the nature, using monopalmitin and monostearin as reference standards. The formation of precipitate reduced the levels of monoacylglycerols in the beef tallow biodiesel. GC-FID and LCMS- IT-TOF results confirmed the nature of the deposit as saturated monoacylglycerols, predominantly monostearin and monopalmitin as the second major component. Moreover the TG analysis of the residue indicated similar thermal decomposition of the reference standards. The precipitate did not affect the oxidation stability of beef tallow biodiesel and the CFPP characteristic of blends up B60. However, the presence of iron reduced significantly the oxidation stability of biodiesel / A produ??o de biodiesel aumentou na ?ltima d?cada em fun??o dos benef?cios associados a este combust?vel, incluindo renovabilidade, mat?rias-primas nacionais, menor toxicidade e biodegradabilidade. Desde 2008, o uso do sebo bovino como mat?ria-prima na produ??o de biodiesel no Brasil tem aumentado em import?ncia, representando a segunda fonte de produ??o, depois da soja No entanto, o desempenho do biodiesel em condi??es de clima frio ? pior que do ?leo diesel devido ? ocorr?ncia de materiais insol?veis a baixas temperaturas, acelerando o entupimento de filtros e injetores de motores de ve?culos. Estudos t?m sido realizados acerca do biodiesel de sebo bovino, em sua maioria relacionados ?s propriedades de estabilidade t?rmica e oxidativa; no entanto, poucos abordam a natureza do precipitado formado e sua influ?ncia na qualidade do biodiesel. Pesquisas sugerem que a causa da deposi??o esteja relacionada ? natureza de ?steres saturados, sendo os monoacilglicer?is prov?veis agentes indutores. Este trabalho apresenta os n?veis de mono-, di- e triacilglicer?is, a estabilidade ? oxida??o e o ponto de entupimento de filtro a frio (PEFF) de amostras de biodiesel de sebo bovino de dois produtores comerciais, avaliados por um per?odo de 12 meses. Amostras de precipitados filtrados foram analisadas pelas t?cnicas comparativas de CG-DIC, CLAE-UV/VIS, CLAE-MS-IT-TOF e TG para verificar a composi??o, utilizando monopalmitina e monoestearina como padr?es de refer?ncia. Verificou-se que a forma??o de precipitado reduziu os n?veis de monoacilglicer?is no biodiesel de sebo bovino. Os resultados cromatogr?ficos confirmaram a natureza do precipitado como monoacilglicer?is saturados, com predomin?ncia de monoestearina e monopalmitina como segundo componente majorit?rio. Al?m disso, a an?lise de TG do precipitado resultou perfil de decomposi??o t?rmica semelhante ao dos padr?es de refer?ncia. O dep?sito formado n?o afetou a estabilidade ? oxida??o do biodiesel de sebo bovino e a caracter?stica de PEFF em misturas at? B60. No entanto, a presen?a de ferro reduziu significativamente a estabilidade ? oxida??o do biodiesel

Made available in DSpace on 2014-12-17T15:42:13Z (GMT). No. of bitstreams: 1 PauloRP_TESE.pdf: 5284084 bytes, checksum: 2ea3c93a4c25ad32fe7fad362cf7de36 (MD5) Previous issue date: 2011-06-28 / Biodiesel production has increased over the last decade because of the benefits associated with this fuel, including renewability, domestic feedstock, lower toxicity, and biodegradability. From 2008, the use of beef tallow as a feedstock for biodiesel production in Brazil has increased in significance, representing the second largest source of biodiesel, after soybeans. However, the performance of biodiesel in cold weather conditions is worse than diesel because of deposition of insoluble at low temperatures, accelerating the plugging of fuel filters and injectors of the vehicle engine. Studies have been conducted on beef tallow biodiesel, mostly related to the properties of thermal and oxidative stability. However, few studies have described the nature of the precipitate formed and its influence on product quality. Research suggests that the cause of deposition is related to the nature of saturated esters and monoacylglycerols as inducing agents. This study monitored the levels of mono-, diand triacylglycerols, the oxidation stability and the cold filter plugging point (CFPP) in beef tallow biodiesel samples from two commercial producers in Brazil for a period of twelve months. Filtered precipitates were analyzed by comparative techniques of GCFID, HPLC-UV/VIS, HPLC-MS-IT-TOF and TG to verify the nature, using monopalmitin and monostearin as reference standards. The formation of precipitate reduced the levels of monoacylglycerols in the beef tallow biodiesel. GC-FID and LCMS- IT-TOF results confirmed the nature of the deposit as saturated monoacylglycerols, predominantly monostearin and monopalmitin as the second major component. Moreover the TG analysis of the residue indicated similar thermal decomposition of the reference standards. The precipitate did not affect the oxidation stability of beef tallow biodiesel and the CFPP characteristic of blends up B60. However, the presence of iron reduced significantly the oxidation stability of biodiesel / A produ??o de biodiesel aumentou na ?ltima d?cada em fun??o dos benef?cios associados a este combust?vel, incluindo renovabilidade, mat?rias-primas nacionais, menor toxicidade e biodegradabilidade. Desde 2008, o uso do sebo bovino como mat?ria-prima na produ??o de biodiesel no Brasil tem aumentado em import?ncia, representando a segunda fonte de produ??o, depois da soja No entanto, o desempenho do biodiesel em condi??es de clima frio ? pior que do ?leo diesel devido ? ocorr?ncia de materiais insol?veis a baixas temperaturas, acelerando o entupimento de filtros e injetores de motores de ve?culos. Estudos t?m sido realizados acerca do biodiesel de sebo bovino, em sua maioria relacionados ?s propriedades de estabilidade t?rmica e oxidativa; no entanto, poucos abordam a natureza do precipitado formado e sua influ?ncia na qualidade do biodiesel. Pesquisas sugerem que a causa da deposi??o esteja relacionada ? natureza de ?steres saturados, sendo os monoacilglicer?is prov?veis agentes indutores. Este trabalho apresenta os n?veis de mono-, di- e triacilglicer?is, a estabilidade ? oxida??o e o ponto de entupimento de filtro a frio (PEFF) de amostras de biodiesel de sebo bovino de dois produtores comerciais, avaliados por um per?odo de 12 meses. Amostras de precipitados filtrados foram analisadas pelas t?cnicas comparativas de CG-DIC, CLAE-UV/VIS, CLAE-MS-IT-TOF e TG para verificar a composi??o, utilizando monopalmitina e monoestearina como padr?es de refer?ncia. Verificou-se que a forma??o de precipitado reduziu os n?veis de monoacilglicer?is no biodiesel de sebo bovino. Os resultados cromatogr?ficos confirmaram a natureza do precipitado como monoacilglicer?is saturados, com predomin?ncia de monoestearina e monopalmitina como segundo componente majorit?rio. Al?m disso, a an?lise de TG do precipitado resultou perfil de decomposi??o t?rmica semelhante ao dos padr?es de refer?ncia. O dep?sito formado n?o afetou a estabilidade ? oxida??o do biodiesel de sebo bovino e a caracter?stica de PEFF em misturas at? B60. No entanto, a presen?a de ferro reduziu significativamente a estabilidade ? oxida??o do biodiesel