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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Effects of isolation condition and spray drying on camelina gum yield and properties

Cao, Xiwen January 1900 (has links)
Master of Science / Department of Biological & Agricultural Engineering / Donghai Wang / Camelina sativa (L). Crantz that belongs to Brassicaceae family has been grown as a dicotyledonous oilseed crop in the cold places like America and Canada. Camelina seeds are widely used for the extraction of oil and protein. Recently, research found that camelina gum is an excellent candidate for food and industrial uses as thickener or stabilizer. The objectives of this research were 1) to increase camelina gum isolation efficiency using spray drying technology, and 2) to develop an innovative method to remove gum from seed bran to increase protein and oil extraction efficiency and quality. The camelina gums isolated using ethanol precipitation and spray drying method from the whole camelina seeds were compared. Effects of spray drying temperature on yield, gum morphology, and gum rheological and thermal properties were studied. The representative sample dried at 165°C was chosen to study the effects of concentration, temperature, pH and additives (NaCl, CaCl₂, sucrose, and ethanol) on viscosity and viscoelastic properties of the isolated gum. The gum showed a shear thinning behavior when shear rate increased gradually, higher concentrations of additives only slightly affect the rheological properties. Results showed that spray drying is an effective method in terms of saving time and energy, and provided positive rheology benefits on camelina gum isolation. Pre-removal of gum from camelina seeds can increase protein and oil yield and their quality. Decortication can separate 10-17% of the total camelina seed as bran. A wind tunnel was used to separate lighter bran particles from heavier endosperm and unbroken seeds. Camelina gum isolation from the separated seed bran using the traditional ethanol precipitation method was optimized using response surface methodology where the simultaneous effect of the three independent variables (seed bran to water ratio, isolation temperature, and isolation time) were investigated for gum yield, purity, and optimum rheological properties. Three independent quadratic modules were developed and the original data fitted the models fitted (R² = 0.995, 0.877, and 0.804). The optimal isolation conditions were seed bran to water ratio of 1:39, isolation temperature of 35 ºC, and isolation time of 1.5 h and 0.839 desirability was obtained by the rigorous statistics analysis. The protein yield and quality extracted from decorticated endosperm were improved significantly compared with that extracted from whole seeds meal without decortication. In addition, the degumming step can be eliminated before protein and oil extraction that increase protein and oil extraction efficiency.
32

O emprego da metodologia de superfície de resposta no desenvolvimento de um novo produto simbiótico, fermentado com Enterococcus faecium CRL 183 e Lactobacillus helveticus ssp jugurti 416, à base de extratos aquosos de soja e de Yacon (Smallanthus sonchifolius)

Silveira, Nadiége Dourado Pauly [UNESP] 06 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-06Bitstream added on 2014-06-13T20:50:17Z : No. of bitstreams: 1 silveira_ndp_me_arafcf.pdf: 632968 bytes, checksum: 566fea3e37e0a1dbca16d6a35e7a7aa1 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O desenvolvimento de alimentos funcionais tem aumentado mundialmente devido a seus compostos bioativos que diminuem o risco de doenças e promovem a saúde. Baseado nisso, a indústria e a comunidade científica estão, cada vez mais, buscando ingredientes que possam conferir tais características aos alimentos. A soja, além de ser importante fonte protéica, possui fibras, isoflavonas, oligossacarídeos com potencial prebiótico (rafinose e estaquinose), vitaminas e minerais. As raízes tuberosas de yacon (Smallanthus sonchifolius) possuem grande quantidade de frutooligossacarídeos do tipo inulina, um componente não digerível pelo nosso organismo, com função de auxiliar na seleção de determinadas bactérias da microbiota intestinal, principalmente as bifidobactérias, possuindo, portanto, efeito prebiótico. O objetivo do presente estudo foi o de verificar, através da metodologia da superfície de resposta, as melhores condições para a utilização simultânea de extratos aquosos de soja e de yacon no desenvolvimento de um novo produto fermentado por um cultivo probiótico constituído por Enterococcus faecium CRL 183 e Lactobacillus helveticus ssp jugurti 416. Para tanto, as variáveis independentes foram representadas pelo teor protéico fornecido pelo extrato hidrossolúvel de soja (g/L) e pelo extrato aquoso de yacon (%). As variáveis dependentes (respostas) foram obtidas através do teste de aceitação sensorial (“sabor” e “impressão global”). A otimização conjunta das variáveis apontou a formulação 7 (1,74 g/L de teor protéico fornecido pelo extrato de soja e 25,86% de extrato de yacon) do planejamento experimental como sendo a mais adequada. No entanto, as formulações 9 e 10 (ambas contendo 1,74 g/L de teor protéico fornecido pelo extrato de soja e 40% de extrato de yacon) apresentaram valores de aceitação que não diferiram significativamente... / World-wide the development of functional food has been increased, due to its bioactive components which decrease the risk of getting some illnesses and promote health. Based on that, the industry and the scientific population are more and more searching for ingredients that may confer such characteristics to food. The soy, besides being an important proteic source, has fibers and isoflavones, oligosaccharides with potential prebiotic (raffinose and stachyose), vitamins and minerals. The yacon tuber (Smallanthus sonchifolius) is a source of fructooligosaccharides, type inulin, undigestible components by our organism that helps in the selection and development of some bacteria of intestinal microbiota, mainly the bifidobacteria, which means that yacon has prebiotic effect. The aim of this study was to check, through Response Surface Methodology, the optimum conditions to use, simultaneously, the soy and yacon watery extracts in the development of a new fermented product with the probiotic cultive constituted by Enterococcus faecium CRL 183 and Lactobacillus helveticus ssp jugurti 416. Therefore, the independent variables were represented by the protein of soymilk (g/L) and the yacon extract (%). The dependent variables (responses) were obtained through the acceptance test (“taste” and “overall acceptability”). The joint optimization of the variables pointed out the 7th formulation (1.74 g/L of soymilk protein and 25.86% of yacon extract) of the factorial design as the most adequate. However, the 9th and 10th formulations (both containing 1.74 g/L of soymilk protein and 40% of yacon extract) presented acceptance scores significantly equal to the 7th treatment. The optimized product was submitted to the shelf-life determination, and it was presented in conditions of consuming in the course of 21 days at 5 ºC and with viability of the probiotic cultive among... (Complete abstract click electronic access below)
33

OtimizaÃÃo da extraÃÃo de taninos da casca do cajueiro. / Optimization of tannin extraction from cashew bark.

Adriana Dutra Sousa 20 February 2013 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Taninos sÃo substÃncias polifenÃlicas que fazem parte dos metabÃlitos secundÃrios de vegetais. Tais compostos tÃm sido muito utilizados no curtimento de couro, como substitutos de fenol na produÃÃo de adesivos para madeira e em aplicaÃÃes mÃdicas. As principais fontes de taninos sÃo cascas de Ãrvores, e de acordo com alguns estudos, o caule de cajueiro possui grande potencial para ser utilizado como fonte de taninos. Nesse contexto, o objetivo deste trabalho foi otimizar a extraÃÃo de taninos da casca de cajueiro. Inicialmente, conduziram-se experimentos para avaliar o efeito de diferentes solventes sobre a extraÃÃo de taninos condensados (TC) e polifenÃis totais (PT). A tÃcnica de extraÃÃo utilizada foi a maceraÃÃo dinÃmica. TambÃm foi realizado um planejamento experimental para estudar a influÃncia de algumas variÃveis crÃticas (tempo, temperatura e razÃo lÃquido/sÃlido) sobre a extraÃÃo aquosa de PT e TC, alÃm do efeito sobre o teor de sÃlidos totais (TST). Testou-se o efeito da reutilizaÃÃo da casca e do solvente na extraÃÃo de TC e por fim foi avaliado o efeito da secagem por atomizaÃÃo e por liofilizaÃÃo sobre os extratos. De acordo com os resultados, os extratos obtidos com etanol 50% em Ãgua apresentaram maiores quantidades de PT e TC em relaÃÃo aos outros solventes. A variÃvel razÃo lÃquido/sÃlido foi o fator mais importante para todas as respostas, apresentando efeito positivo para PT e TC e efeito negativo para sÃlidos totais. TambÃm foi observado que hà uma relaÃÃo diretamente proporcional entre a temperatura e os teores de PT e TC. E o fator tempo sà foi significativo para TC, onde foi observado que o tempo de 100 minutos favoreceu a extraÃÃo. Avaliando a relaÃÃo das variÃveis, a melhor condiÃÃo encontrada para obter maiores teores de taninos foi: temperatura de 100ÂC, por 100 minutos e razÃo L/S 30:1. Nessa condiÃÃo, o teor de TC extraÃdos foi de 7,63 mg equivalente de catequina/ 100 mg casca. A utilizaÃÃo do mesmo solvente em atà duas extraÃÃes se mostrou viÃvel para a extraÃÃo de TC, ao contrÃrio da casca que, ao ser extraÃda uma segunda vez, proporcionou ganhos mÃnimos. A secagem por atomizaÃÃo se mostrou mais adequada para aplicaÃÃo industrial em comparaÃÃo com a liofilizaÃÃo. / Tannins are secondary plant metabolites with polyphenolic structure. These compounds have been used in leather tanning, also as replacement for phenol in adhesives manufacture for wood and medical applications. The main sources of these compounds are tree barks, and according to some studies, the stem cashew has great potential to be a source of tannins. In this context, the aim of this study was to optimize the tannins extraction from the cashew bark. Initially, experiments were performed to evaluate the effect of different solvents on the condensed tannins (CT) and total polyphenols (TP) extraction. Dynamic maceration was the technique used for extraction. An experimental design was conducted to understand the influence of some critical variables (time, temperature and liquid/solid ratio) on aqueous extraction of TP and CT, as well as the effect on total solids content (TSC). We tested the effect of bark and solvent reuse in the CT extraction and finally it was evaluated the effect of extracts freeze drying and spray drying. According to results, the extracts obtained with 50% ethanol in water showed higher amounts of TP and CT when compared to other solvents. The variable liquid/solid ratio, the most important factor for all responses, showed positive effect for TP and CT and negative effect on total solids. There is a directly proportional relationship between temperature and levels of TP and CT. Time factor was significant only for CT, where it was observed that 100 minutes favored the extraction. Evaluating the variables relationship, the best condition found for higher levels of tannins was: temperature of 100ÂC for 100 minutes and liquid/solid ratio 30:1. In this condition, the amount of CT extracted was 7.63 mg catechin equivalent / 100 mg bark. In extraction process, solvent used twice is feasible to extract CT. Unlike the bark, that obtained minimal gains in a second extraction. Spray drying was more suitable for industrial application compared to freeze drying.
34

Desenvolvimento de cereal matinal extrusado organico a base de farinha de milho e farelo de maracuja / Development of an organic extruded breakfast cereal using corn flour and passion fruit fiber

Vernaza Leoro, Maria Gabriela 29 March 2007 (has links)
Orientador: Caroline Joy Steel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T12:05:36Z (GMT). No. of bitstreams: 1 VernazaLeoro_MariaGabriela_M.pdf: 2963475 bytes, checksum: 26fde35fc78447f593f66f139fddbf2b (MD5) Previous issue date: 2007 / Resumo: É cada vez maior o número de pessoas que procura uma alimentação mais saudável, com alimentos frescos, de boa qualidade biológica e livre de defensivos agrícolas, como são os produtos orgânicos. Percebe-se também que nas dietas contemporâneas em geral existe um "déficit nutricional" de fibras. Este fato tem motivado as autoridades de saúde de diversos países a estimular um maior consumo de fibras por parte da população adulta, seja estimulando o consumo de alimentos como frutas, verduras, leguminosas, raízes, tubérculos e cereais integrais, ou através de produtos comerciais de consumo habitual que tenham sido enriquecidos com fibras. Já existem no mercado ou têm sido estudadas algumas fontes alternativas de fibras, como as fibras de beterraba, de caule de trigo, de laranja, de maracujá e a quitosana. Neste trabalho, optou-se por aproveitar os resíduos da extração de polpa de maracujá como fonte alternativa de fibras. Na extração de polpas e sucos, os resíduos resultantes do processo são normalmente utilizados em ração animal ou como adubo. O objetivo deste trabalho foi estudar o efeito de parâmetros da extrusão termoplástica (umidade da matéria-prima e temperatura de processo) e da adição de fibra sobre propriedades físicas, propriedades físico-químicas e propriedades nutricionais de produtos extrusados, no desenvolvimento de cereal matinal orgânico à base de farinha de milho e farelo de maracujá. A matéria-prima foi caracterizada quanto a sua composição centesimal; teores de fibra alimentar total, solúvel e insolúvel; índices de solubilidade em água (ISA), de absorção de água (IAA), de solubilidade em leite (ISL), de absorção de leite (IAL), de absorção de óleo (IAO), índice glicêmico (IG) e teor de compostos cianogênicos. Após a caracterização da matéria-prima, foi utilizado o processo de extrusão termoplástica para produzir uma base para cereal matinal, otimizando-se a formulação e os parâmetros de extrusão através da Metodologia de Superfície de Resposta, visando a obtenção de um produto com "alto teor de fibras" e propriedades tecnológicas adequadas. Os produtos extrusados foram caracterizados quanto a propriedades físicas, como índice de expansão (IE), cor, dureza e manutenção da textura em leite; propriedades físico-químicas, como ISA, IAA, ISL, IAL e IAO; e propriedades nutricionais, como IG e teor de compostos cianogênicos. Foi observado que o farelo de maracujá utilizado continha alto teor de fibra alimentar total (64,11%), apresentando teores significativos de fibra insolúvel (50,16%) e fibra solúvel (13,95%), ao contrário da farinha de milho que apresentou baixo teor de fibra alimentar total (3,68%), sendo 3,37% fibra insolúvel e 0,31% fibra solúvel. Os valores encontrados na determinação do ISA da farinha de milho e do farelo de maracujá foram 7,14 e 31,66%, respectivamente. O valor do IAA encontrado para a farinha de milho foi de 3,33 g de água/g material seco e para o farelo de maracujá foi de 14,38 g de água/g material seco. Os valores encontrados para o ISL da farinha de milho e do farelo de maracujá foram 5,23 e 14,53%, respectivamente. Os valores do ISL foram menores quando comparados com os valores do ISA. Os valores do IAL encontrados para a farinha de milho e para o farelo de maracujá foram de 3,26 e 12,50 g de leite/g material seco, maiores que os valores de IAA, possivelmente devido à formação de géis de pectina. Os índices de absorção de óleo da farinha de milho e do farelo de maracujá foram de 3,63 e 4,74 g de óleo/g de material seco, respectivamente. Os índices glicêmicos da farinha de milho e do farelo de maracujá foram de 48,03 e 45,00%, respectivamente. O farelo de maracujá apresentou um teor de compostos cianogênicos totais de 748,3 mg/kg. As superfícies de resposta demonstraram que a valores baixos das variáveis estudadas, foi obtida a maior expansão. Já, sobre a dureza dos produtos extrusados, as superfícies demonstraram que o efeito mais importante foi a umidade e a interação dela com a temperatura. Ao aumentar a umidade, a dureza dos produtos extrusados aumentou significativamente. No entanto, foi observado que a temperatura de processo foi o parâmetro que mais influenciou negativamente a textura do produto após 5 minutos de imersão em leite. Em relação à cor dos extrusados, altos níveis de farelo de maracujá diminuíram os valores de L* e hab, produzindo extrusados mais escuros e menos amarelos, ao contrário do efeito da temperatura, onde altas temperaturas aumentaram o valor de L* e o hab, produzindo extrusados mais claros e mais amarelos. Nos produtos extrusados, os maiores valores de ISA foram encontrados para os maiores teores de farelo de maracujá, enquanto que os maiores valores para o IAO foram obtidos com baixos teores de farelo. Aparentemente, não houve efeito das variáveis estudadas sobre o IG dos produtos extrusados. O teor dos compostos cianogênicos foi maior nos produtos com maiores teores de farelo de maracujá, como esperado. Além disso, parace haver um efeito da umidade da matéria-prima na redução dos compostos cianogênicos durante o processo de extrusão. O extrusado considerado como produto ótimo neste trabalho apresentou propriedades adequadas com respeito a IE e dureza. Também apresentou uma porcentagem de fibra alimentar alta (11%), bem superior à exigida pela Legislação Brasileira (6 g/100 g de produto) para ser denominado cereal matinal "com alto teor de fibras" / Abstract: The number of people searching healthier eating habits, including fresh foods of good biological quality and free of pesticides, such as organic products, is increasing. It is also observed that in contemporary diets in general, there is a â?¿nutritional deficitâ?? of fibers. This fact has motivated health authorities of several countries to stimulate a greater ingestion of fibers by the adult population, either by stimulating the consumption of fruits, vegetables, legumes, tubers and wholegrain cereals, or through the enrichment of commonly consumed commercial products. There are already a few alternative fiber sources on the market or under study, such as beetroot, wheat stalk, orange, passion fruit fibers and chitosan. In this work, we opted to use the residues from the extraction of passion fruit pulp as an alternative fiber source. In the extraction of pulps and juices, the residues are usually used as animal feed or fertilizers. The objective of this work was to study the effect of thermoplastic extrusion parameters (raw material moisture content and process temperature) and fiber addition on physical, physical-chemical and nutritional properties of extruded products, as a step in the development of an organic breakfast cereal based on corn flour and passion fruit fiber. The raw material was characterized as to its proximate composition; total, soluble and insoluble fiber contents; water solubility index (WSI), water absorption index (WAI), milk solubility index (MSI), milk absorption index (MAI), oil absorption index (OAI); glycemic index (GI) and cyanogenic compounds. After characterization of the raw material, the thermoplastic extrusion process was used to produce a base for breakfast cereals, optimizing the formulation and process parameters through the Response Surface Methodology, with the aim of obtaining a â?¿high fiber contentâ?? product with adequate technological properties. The extruded products were characterized with respect to physical properties, such as expansion index (EI), color, hardness and maintenance of texture in milk; physicalchemical properties, such as WSI, WAI, MSI, MAI and OAI; and nutritional properties, such as GI and cyanogenic compounds. It was observed that the passion fruit fiber used had a high total fiber content (64.11%), presenting significant contents of insoluble (50.16%) and soluble (13.95%) fibers, different to the corn flour used that presented a low total fiber content (3.68%), of which 3.37% were insoluble fibers and 0.31% soluble fibers. The values found for the WSI of the corn flour and passion fruit fiber were 7.14 and 31.66%, respectively. The values found for the WAI of the corn flour and of the passionfruit fiber were 3.33 and 14.38 g water/g dry material, respectively. The values found for the MSI of the corn flour and passion fruit fiber were 5.23 and 14.53%, respectively. The MSI values were lower than the WSI values. The values found for the MAI of the corn flour and passion fruit fiber were 3.26 and 12.50 g milk/g dry material, higher than those of WAI, possibly due to the formation of pectin gels. The oil absorption indices of the corn flour and passion fruit fiber were 3.63 and 4.74 g oil/g dry material, respectively. The glycemic indices of the corn flour and passion fruit fiber were 48.03 and 45.00%, respectively. The content of cyanogenic compounds in passion fruit fiber were 748,3 mg/kg. The response surfaces demonstrated that at low values of the variables studied, greatest expansion was obtained. For the hardness of the extruded products, the surfaces demonstrated that the most important effect was moisture and its interaction with temperature. Increasing moisture, the hardness of the extruded products increased significantly. However, it was observed that process temperature was the parameter that had the greatest negative effect on the texture of the products after 5 minutes in milk. With respect to color of the extrudates, high levels of passion fruit fiber reduced L* and hab values, producing darker and less yellow extrudates, different to the effect of temperature, where high temperatures increased L* and hab values, producing lighter and more yellow extrudates. In the extruded products, the highest values for WSI were found with the highest passion fruit fiber contents, while the highest values for OAI were obtained with low fiber contents. Apparently, there was no effect of the variables studied on the GI of the extruded products. The content of cyanogenic compounds was higher in the products with greater percentages of passion fruit fiber, as expected. Apart from this, there seems to be an effect of raw material moisture content in the reduction of cyanogenic compounds during the extrusion process. The extrudate considered optimum in this work presented adequate properties with respect to EI and hardness. It also presented a high percentage of dietary fiber (11%), higher than that required by the Brazilian Legislation (6 g/100 g product) to be labeled as a â?¿high fiber contentâ?? breakfast cereal / Mestrado / Mestre em Tecnologia de Alimentos
35

Statistical Analysis and Optimization of Ammonia Removal from Aqueous Solution by Zeolite and Ion-exchange Resin

Ding, Yuanhao January 2015 (has links)
The ability of natural zeolite and synthetic ion-exchange resin for ammonia removal from aqueous solution was studied through batch experiments. The results showed that both zeolite and ion-exchange resin were effective (up to 87% of removal) in eliminating ammonia from aqueous solution. Factorial design and response surface methodology were applied to evaluate and optimize the effects of pH, dose, contact time, temperature and initial ammonia concentration. Low pH condition was preferred with the optimum pH found to be 6 for both zeolite and ion-exchange resin. High dose generated high removal rate and low exchange capacity. Results of factorial design and response surface methodology showed that temperature was not a significant parameter. The model prediction was in good agreement with observed data (R2 = 0.969 for zeolite and R2 = 0.957 for resin, respectively). For zeolite, the optimum Qe was 22.90 mg/g achieved at pH=7 and initial ammonia concentration of 3000 mg/L. For ion-exchange resin, Qe of 28.78 mg/g was achieved at pH=6 and initial TAN concentration of 3000 mg/L. The reaction kinetics for both of them followed the Pseudo-second order kinetic model (R2=0.998 and R2=0.999, respectively). Equilibrium data were fitted to Langmuir and Freundlich isotherm models with Freundlich model providing a slightly better predication for zeolite (R2=0.992) and Langmuir providing more accurate prediction for ion-exchange resin (R2=0.996). The ion-exchange resin can be completely regenerated by 2N H2SO4.
36

Statistical Analysis and Optimization of Ammonia Nitrogen Removal from Aqueous Solutions and Landfill Leachate by Ultrasound Iradiation

Tobalt, Andrew January 2017 (has links)
The application of Ultrasound (US) irradiation to remove ammonia nitrogen from aqueous solutions, including synthetic solution and landfill leachate, at 20 kHz was investigated in this thesis. Batch experiments were carried out using two synthetic solutions with initial ammonia concentrations of 3000 and 5000 mg TAN/L in addition to two leachates from new and old landfills. The results of testing showed that US irradiation is an effective treatment technology for the removal of aqueous ammonia. More specifically, it was found that increasing sonication time and pH increased ammonia removal. The maximum observed removal of ammonia was 87.4% at a pH of 11 and sonication time of 25 minutes. Also, it was found that volatilization of ammonia to the atmosphere accounted for 0-7% of removal, the thermal effect of US accounted for 21.1-52.7%, and the non-thermal effect of US accounted for 44.5-78.8% (depending on pH and sonication time). Results of factorial design and response surface methodology showed that pH, energy output (kJ), and the interaction between the two were significant parameters. The predicted two factor interaction (2FI) model was in close agreement to the observed data (R2 = 0.94) and produced an optimum ammonia removal of 87% at a pH of 10.9 and energy output of 94.8 kJ. Analysis of variance tests showed that there were no significant differences in the percent removal of ammonia due to the non-thermal effects of US across all four solutions (synthetic and leachate) indicating that US irradiation is a non-selective treatment method for ammonia removal.
37

Assessment and Optimization of Ex-Situ Bioremediation of Petroleum Contaminated Soil under Cold Temperature Conditions

Gomez, Francisco January 2014 (has links)
Current prices and demand for petroleum hydrocabons have generated an increase of oil spills around the country and the world. Health and environmental impacts associated to these organic pollutants represent a huge concern for the general public, leading the public and private sector to develop new technologies and methods to minimize or eliminate those risks. Ex-Situ bioremediation through biopiles, as a main remediation technique to treat a wide range of hydrocarbons, has been a topic of considerable research interest over the last years. It provides an economical and environmental solution to restore the environment to background levels. Nevertheless, successful bioremediation under cold climate conditions is of considerable concern in countries like Canada, as low temperatures can delay the rate of bioremediation of oil hydrocarbons, thus limiting the operation of soil treatment facilities to certain times of the year. Recent research has found out that bioremediation could be conducted even at low or cold temperatures with larger periods of times. And even more, the addition of petroleum degrading microorganisms (bioaugmentation) and nutrients or biosurfactants (biostimulation) could enhance the process in some cases. In the present study, a comprehensive assessment of bioaugmentation and biostimulation strategies for ex-situ bioremediation of petroleum contaminated soil under cold climate conditions is proposed. Field scale biopiles were constructed and subjected to different concentrations of commercial microbial consortia and mature compost, as bioaugmentation and biostimulation strategies, in a soil treatment facility at Moose Creek, Ontario over a period of 94 days (November 2012 to February 2013). Assessment and comparison of the biodegradation rates of total petroleum hydrocarbons (TPH) and their fractions were investigated. Furthermore, a response surface methodology (RSM) based on a factorial design to investigate and optimize the effects of the microbial consortia application rate and amount of compost on the TPH removal was also assessed. Results showed that biopiles inoculated with microbial consortia and amended with 10:1 soil to compost ratio under aerobic conditions performed the best, degrading 82% of total petroleum hydrocarbons (TPHs) with a first-order kinetic degradation rate of 0.016 d_1, under cold temperature conditions. The average removal efficiencies for TPHs after 94 days for control biopiles, with no amendments or with microbial consortia or compost only treatments were 48%, 55%, and 52%, respectively. Statistical analyses indicated a significant difference (p < 0.05) within and between the final measurements for TPHs and a significant difference between the treatment with combined effect, and the control biopiles. On the other hand, the modeling and optimization statistical analysis of the results showed that the microbial consortia application rate, compost amendment and their interactions have a significant effect on TPHs removal with a coefficient of determination (R2) of 0.88, indicating a high correlation between the observed and the predicted values for the model obtained. The optimum concentrations predicted via RSM were 4.1 ml m-3 for microbial consortia application rate, and 7% for compost amendment to obtain a maximum TPH removal of 90.7%. This research contributes to provide valuable knowledge to practitioners about cost-effective and existing strategies for ex-situ bioremediation under cold weather conditions.
38

Simulation-based process design and integration for retrofit

Hernandez Enriquez, Aurora January 2010 (has links)
This research proposes a novel Retrofit Design Approach based on process simulation and the Response Surface Methodology (RSM).Retrofit Design Approach comprises: 1) a diagnosis stage in which the variables are screened and promising variables to improve system performance are identified through a sensitivity analysis, 2) an evaluation stage in which RSM is applied to assess the impact of those promising variables and the most important factors are determined by building a reduced model from the process response behaviour, and 3) an optimisation stage to identify optimal conditions and performance of the system, subject to objective function and model constraints. All these stages are simulation-supported. The main advantages of the proposed Retrofit Design Approach using RSM are that the design method is able to handle a large industrial-scale design problem within a reasonable computational effort, to obtain valuable conceptual insights of design interactions and economic trade-off existed in the system, as well as to systematically identify cost-effective solutions by optimizing the reduced model based on the most important factors. This simplifies the pathway to achieve pseudo-optimal solutions, and simultaneously to understand techno-economic and system-wide impacts of key design variables and parameters. In order to demonstrate the applicability and robustness of the proposed design method, the proposed Retrofit Design Approach has been applied to two case studies which are based on existing gas processing processes. Steady-state process simulation using Aspen Plus TM® has been carried out and the simulation results agree well with the plant data. Reduced models for both cases studies have been obtained to represent the techno-economic behaviour of plants. Both the continuous and discrete design options are considered in the retrofitting of the plant, and the results showed that the Retrofit Design Approach is effective to provide reliable, cost-effective retrofit solutions which yield to improvements in the studied processes, not only economically (i.e. cost and product recovery), but also environmentally linked (i.e. CO₂ emissions and energy efficiency). The main retrofitting solutions identified are, for the first case, column pressure change, pump-around arrangement and additional turbo-expansion capacity, while for the second case, columns pressure change, trays efficiency, HEN retrofit arrangements (re-piping) and onsite utility generation schemes are considered. These promising sets of retrofit design options were further investigated to reflect implications of capital investment for the retrofit scenarios, and this portfolio of opportunities can be very useful for supporting decision-making procedure in practice. It is important to note that in some cases a cost-effective retrofit does not always require structural modifications. In conclusion, the proposed Retrofit Design Approach has been found to be a reliable approach to address the retrofit problem in the context of industrial applications.
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Estudo da influência dos parâmetros de injeção de combustível no ruído emitido por motores diesel, fazendo uso do planejamento multivariado de experimentos / Study of the influence of the fuel injection parameters on the noise emitted by diesel engines, using the multivariate design of experiments

Rodrigues, Marlon Casagrande 06 October 2011 (has links)
Orientador: Roy Edward Bruns / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T11:44:59Z (GMT). No. of bitstreams: 1 Rodrigues_MarlonCasagrande_M.pdf: 2084739 bytes, checksum: 4206c434cf21dfc145d73ca304a9981b (MD5) Previous issue date: 2011 / Resumo: Nos últimos anos a emissão de ruído tem sido decisiva para aceitação de veículos no mercado, não somente devido a legislação, mas também no que diz respeito a satisfação do cliente. Por este motivo as empresas fabricantes de veículos e ou motores de combustão interna tem sido obrigadas a dar uma atenção especial as emissões de ruído para poderem competir com suas concorrentes. Neste trabalho realizou-se estudo da influencia dos parâmetros de injeção de combustível do motor MWM 6.12 TCE no nível de ruído emitido pelo motor Diesel na condição de marcha lenta, por meio da técnica de planejamento multivariado de experimentos. Foram escolhidas duas técnicas de medição indireta de ruído (ruído de combustão e aceleração na saia do bloco) para serem utilizadas como variável resposta do planejamento de experimentos. Para verificação da eficácia dos planejamentos realizou-se ensaios qualitativos e quantitativos de ruído propriamente dito. Foi feito um planejamento fatorial fracionário 28-4 para fazer uma triagem de oito fatores de acordo com seus efeitos nas respostas aceleração na saia do bloco e ruído de combustão. Os fatores com efeitos mais significativos, pressão do rail, ponto de injeção principal, ponto de pré-injeção 2 e debito da pré-injeção 2, foram investigados usando um planejamento composto central e superfícies de respostas foram determinadas para cada uma das respostas. Os resultados mostraram que apenas a variável resposta vibração na saia do bloco apresentou resultados satisfatórios para esta condição especifica do motor tanto nos testes quantitativos como qualitativos (redução de 2 dB e melhora na qualidade sonora respectivamente). Apos verificação da influencia dos parâmetros de injeção no ruído emitido verificou-se também a influencia destas alterações no consumo de combustível e emissões dos gases de escape e foi observado que existem influencias significativas nas emissões dos gases de escape / Abstract: In recent years the noise level has been decisive for acceptance of vehicles on the market, not only because of legislation but also with regard to customer satisfaction. For this reason the manufacturers of vehicles and internal combustion engines have been forced to give special attention to the emission of noise to compete with their competitors. In this work, the influences of fuel injection parameters on the noise level of the MWM 6.12 TCE diesel engine emitted under low idle condition were determined using multivariate statistical design of experiments. Two techniques for the indirect measurement of noise, combustion noise and engine crankcase vibration, were chosen as the response variables for the experimental design. To check design effectiveness both qualitative and quantitative noise measurements were carried out. A 28-4 fractional factorial design was performed to screen eight factors according to their effects on engine crankcase vibration, and combustion noise. The factors with the most significant effects, rail pressure, pre-injection point, main injection point and the pre-injection delivery, were investigated using a central composite design and response surfaces were determined for each response. The results showed that only the engine crankcase vibration showed satisfactory results for this particular engine condition in both the quantitative and qualitative analyses (reduction of 2 dB and an improvement in sound quality, respectively). After verification of the influences of the injection parameters on the noise the influences of these changes on fuel consumption and exhaust emissions were also analyzed. Significant influences were observed on the exhaust gas emissions / Mestrado / Projetos / Mestre em Engenharia Automobilistica
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Design Optimization of Nozzle Shapes for Maximum Uniformity of Exit Flow

Quintao, Karla K 09 November 2012 (has links)
The objective of this study is to identify the optimal designs of converging-diverging supersonic and hypersonic nozzles that perform at maximum uniformity of thermodynamic and flow-field properties with respect to their average values at the nozzle exit. Since this is a multi-objective design optimization problem, the design variables used are parameters defining the shape of the nozzle. This work presents how variation of such parameters can influence the nozzle exit flow non-uniformities. A Computational Fluid Dynamics (CFD) software package, ANSYS FLUENT, was used to simulate the compressible, viscous gas flow-field in forty nozzle shapes, including the heat transfer analysis. The results of two turbulence models, k-e and k-ω, were computed and compared. With the analysis results obtained, the Response Surface Methodology (RSM) was applied for the purpose of performing a multi-objective optimization. The optimization was performed with ModeFrontier software package using Kriging and Radial Basis Functions (RBF) response surfaces. Final Pareto optimal nozzle shapes were then analyzed with ANSYS FLUENT to confirm the accuracy of the optimization process.

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