Este trabalho apresenta uma ferramenta flexível e eficiente para o campo de projeto e desenho preliminar de cascos de embarcações. O estado da arte de projeto de cascos de embarcações consiste em um processo iterativo onde, primeiramente, definem-se parâmetros geométricos, de estabilidade, e hidrodinâmicos. Em seguida, o casco é modelado através de curvas paramétricas. submetido a uma análise de desempenho, e, após isso, é feita a tomada de decisão para otimizar os parâmetros iniciais. O ciclo se repete até que se atinja o resultado desejado. O que será apresentado cumpre com a parte de modelagem paramétrica, e é capaz de gerar de forma automática e otimizada curvas que compõem o projeto de uma embarcação de recreio. A ferramenta recebe parâmetros de alto nível, como razões adimensionais, coeficientes de forma e restrições, e desenha tridimensionalmente um casco intrinsecamente suave, de forma que todos os parâmetros especificados sejam atendidos. Uma metodologia de projeto de cascos de veleiros é utilizada em conjunto com curvas B-Splines, submetidas a um algoritmo de otimização, em cuja função objetivo se empregam critérios de suavidade (\"fairness criteria\"). O problema de otimização de curvas B-Splines é não linear, pela própria formulação da função objetivo e suas restrições. Para tal, utiliza-se um método de Programação Quadrática Seqüencial. Para a otimização dos parâmetros principais do casco, utiliza-se uma metodologia de baixo custo, baseada na técnica de Superfície de Resposta, que otimiza uma função de mérito, no caso, a resistência residual, variando-se dois parâmetros do casco. A interface com softwares CAD é desenvolvida com o objetivo de se realizar outras análises, como de curvatura da superfície, além do projeto do restante da embarcação. Neste também pode ser gerado o bloco sólido para integração com softwares de CAM para a usinagem e fabricação do mesmo. / This article presents a flexible and efficient tool to the field of ship project and preliminary design by using an approach of parametric modeling of hull forms. The state of the art of design of hulls consists in an iterative process where, first, geometric, stability and hydrodynamic parameters are defined. After that, the hull is modeled through parametric curves, simulated in a performance analysis software, and, after that, it is taken the decision to optimize the initial parameters. The cycle repeats until it reaches the desired result. This work deals with the part of parametric modeling, and is capable to generate, in an automatic way, optimized curves that compose the design of the hull of a yacht. The tool receives high level parameters, such as non-dimensional ratios, coefficients and restrictions, and draws a three-dimensional hull, intrinsically fair, fulfilling all the specified parameters. A methodology for the design of sail-boats is presented together with B-Splines curves, submitted to an optimization algorithm, using fairness criteria as the objective function. The optimization problem of B-Splines curves is not linear, because of its mathematical formulation, the objective function and constraints adopted. Therefore, a method of Sequential Quadratic Programming is used. For the optimization of the main parameters of the hull, a cost-effective methodology, based on the Surface Response Method, is proposed, optimizing a merit criterion, such as, the residuary resistance, changing two parameters of the hull. The interface with CAD software is implemented in order to allow other analyses, such as surface curvature, and the design of the other parts of the boat. The drawing also can be transformed into a solid model, and integrated with a CAM software to be ready for itsmanufacturing.

ABSTRACT PARAMETER OPTIMIZATION OF CHEMICALLY ACTIVATED MORTARS CONTAINING HIGH VOLUMES OF POZZOLAN BY STATISTICAL DESIGN AND ANALYSIS OF EXPERIMENTS Aldemir, BaSak M.S., Department of Industrial Engineering Supervisor: Prof. Dr. &Ouml / mer Saat&ccedil / ioglu Co-Supervisor: Assoc. Prof. Dr. Lutfullah Turanli January 2006, 167 pages This thesis illustrates parameter optimization of early and late compressive strengths of chemically activated mortars containing high volumes of pozzolan by statistical design and analysis of experiments. Four dominant parameters in chemical activation of natural pozzolans are chosen for the research, which are natural pozzolan replacement, amount of pozzolan passing 45 &amp / #956 / m sieve, activator dosage and activator type. Response surface methodology has been employed in statistical design and analysis of experiments. Based on various second-order response surface designs / experimental data has been collected, best regression models have been chosen and optimized. In addition to the optimization of early and late strength responses separately, simultaneous optimization of compressive strength with several other responses such as cost, and standard deviation estimate has also been performed. Research highlight is the uniqueness of the statistical optimization approach to chemical activation of natural pozzolans.

The focus of this dissertation is on improving decision-maker trade-offs and the development of a new constrained methodology for multiple response surface optimization. There are three key components of the research: development of the necessary conditions and assumptions associated with constrained multiple response surface optimization methodologies; development of a new constrained multiple response surface methodology; and demonstration of the new method. The necessary conditions for and assumptions associated with constrained multiple response surface optimization methods were identified and found to be less restrictive than requirements previously described in the literature. The conditions and assumptions required for a constrained method to find the most preferred non-dominated solution are to generate non-dominated solutions and to generate solutions consistent with decision-maker preferences among the response objectives. Additionally, if a Lagrangian constrained method is used, the preservation of convexity is required in order to be able to generate all non-dominated solutions. The conditions required for constrained methods are significantly fewer than those required for combined methods. Most of the existing constrained methodologies do not incorporate any provision for a decision-maker to explicitly determine the relative importance of the multiple objectives. Research into the larger area of multi-criteria decision-making identified the interactive surrogate worth trade-off algorithm as a potential methodology that would provide that capability in multiple response surface optimization problems. The ISWT algorithm uses an ε-constraint formulation to guarantee a non-dominated solution, and then interacts with the decision-maker after each iteration to determine the preference of the decision-maker in trading-off the value of the primary response for an increase in value of a secondary response. The current research modified the ISWT algorithm to develop a new constrained multiple response surface methodology that explicitly accounts for decision-maker preferences. The new Modified ISWT (MISWT) method maintains the essence of the original method while taking advantage of the specific properties of multiple response surface problems to simplify the application of the method. The MISWT is an accessible computer-based implementation of the ISWT. Five test problems from the multiple response surface optimization literature were used to demonstrate the new methodology. It was shown that this methodology can handle a variety of types and numbers of responses and independent variables. Furthermore, it was demonstrated that the methodology can be successful using a priori information from the decision-maker about bounds or targets or can use the extreme values obtained from the region of operability. In all cases, the methodology explicitly considered decision-maker preferences and provided non-dominated solutions. The contribution of this method is the removal of implicit assumptions and includes the decision-maker in explicit trade-offs among multiple objectives or responses.

No description available.

Doctor of Philosophy / Department of Chemistry / Stefan H. Bossmann / Pancreatic cancer is the fourth leading cause of cancer-related deaths in the USA. Asymptomatic early cancer stages and late diagnosis leads to very low survival rates of pancreatic cancers, compared to other cancers. Treatment options for advanced pancreatic cancer are limited to chemotherapy and/or radiation therapy, as surgical removal of the cancerous tissue becomes impossible at later stages. Therefore, there's a critical need for innovative and improved chemotherapeutic treatment of (late) pancreatic cancers. It is mandatory for successful treatment strategies to overcome the drug resistance associated with pancreatic cancers. Nanotechnology based drug formulations have been providing promising alternatives in cancer treatment due to their selective targeting and accumulation in tumor vasculature, which can be used for efficient delivery of chemotherapeutic agents to tumors and metastases. The research of my thesis is following the principle approach to high therapeutic efficacy that has been first described by Dr. Helmut Ringsdorf in 1975. However, I have extended the use of the Ringsdorf model from polymeric to nanoparticle-based drug carriers by exploring an iron / iron oxide nanoparticle based drug delivery system. A series of drug delivery systems have been synthesized by varying the total numbers and the ratio of the tumor homing peptide sequence CGKRK and the chemotherapeutic drug doxorubicin at the surfaces of Fe/Fe₃O₄-nanoparticles. The cytotoxicity of these nanoformulations was tested against murine pancreatic cancer cell lines (Pan02) to assess their therapeutic capabilities for effective treatments of pancreatic cancers. Healthy mouse fibroblast cells (STO) were also tested for comparison, because an effective chemotherapeutic drug has to be selective towards cancer cells. Optimal Experimental Design methodology was applied to identify the nanoformulation with the highest therapeutic activity. A statistical analysis method known as response surface methodology was carried out to evaluate the in-vitro cytotoxicity data, and to determine whether the chosen experimental parameters truly express the optimized conditions of the nanoparticle based drug delivery system. The overall goal was to optimize the therapeutic efficacy in nanoparticle-based pancreatic cancer treatment. Based on the statistical data, the most effective iron/iron oxide nanoparticle-based drug delivery system has been identified. Its Fe/Fe₃O₄ core has a diameter of 20 nm. The surface of this nanoparticle is loaded with the homing sequence CGKRK (139-142 peptide molecules per nanoparticle surface) and the chemotherapeutic agent doxorubicin (156-159 molecules per surface), This nanoplatform is a promising candidate for the nanoparticle-based chemotherapy of pancreatic cancer.

The Physical Vapour Deposition (PVD) magnetron sputtering process is one of the widely used techniques for depositing thin film coatings on substrates for various applications such as integrated circuit fabrication, decorative coatings, and hard coatings for tooling. In the area of coatings on cutting tools, tool life can be improved drastically with the application of hard coatings. Application of coatings on cutting tools for various machining techniques, such as continuous and interrupted cutting, requires different coating characteristics, these being highly dependent on the process parameters under which they were formed. To efficiently optimise and customise the deposited coating characteristics, PVD process modelling using RSM methodology was proposed. The aim of this research is to develop a PVD magnetron sputtering process model which can predict the relationship between the process input parameters and resultant coating characteristics and performance. Response Surface Methodology (RSM) was used, this being one of the most practical and cost effective techniques to develop a process model. Even though RSM has been used for the optimisation of the sputtering process, published RSM modelling work on the application of hard coating process on cutting tool is lacking. This research investigated the deposition of TiAlN coatings onto tungsten carbide cutting tool inserts using PVD magnetron sputtering process. The input parameters evaluated were substrate temperature, substrate bias voltage, and sputtering power; the out put responses being coating hardness, coating roughness, and flank wear (coating performance). In addition to that, coating microstructures were investigated to explain the behaviour of the developed model. Coating microstructural phenomena assessed were; crystallite grain size, XRD peak intensity ratio I111/I200 and atomic number percentage ratio of Al/Ti. Design Expert 7.0.3 software was used for the RSM analysis. Three process models (hardness, roughness, performance) were successfully developed and validated. The modelling validation runs were within the 90% prediction interval of the developed models and their residual errors compared to the predicted values were less than 10%. The models were also qualitatively validated by justifying the behaviour of the output responses (hardness, roughness, and flank wear) and microstructures (Al/Ti ratio, crystallographic peak ratio I111/1200, and grain size) with respect to the variation of the input variables based on the published work by researchers and practitioners in this field. The significant parameters that influenced the coating hardness, roughness, and performance (flank wear) were also identified. Coating hardness was influenced by the substrate bias voltage, sputtering power, and substrate temperature; coating roughness was influenced by sputtering power and substrate bias; and coating performance was influenced by substrate bias. The analysis also discovered that there was a significant interaction between the substrate temperature and the sputtering power which significantly influenced coating hardness, roughness, and performance; this interaction phenomenon has not been reported in previously published literature. The correlation study between coating characteristics, microstructures and the coating performance (flank wear) suggested that the coating performance correlated most significantly to the coating hardness with Pearson coefficient of determination value (R2) of 0.7311. The study also suggested some correlation between coating performance with atomic percentage ratio of Al/Ti and grain size with R2 value of 0.4762 and 0.4109 respectively.

La thèse vise l'application du concept de bioraffinerie (extraction, fractionnement, séparation de composés à partir de biomasse avant transformation ultérieure), via le développement d'étapes de production destinées à être associées en un procédé continu. La complexité du solide nécessite une étape de prétraitement effectuée avec une technologie à faible impact environnemental et l'eau subcritique est déjà utilisée comme solvant d'extraction des produits naturels, en sus de leur hydrolyse. Ces travaux ont porté sur l'hydrolyse de polysaccharides (son de riz) et de triacylglycérols (TAG, huile de tournesol) choisis comme modèles. Les caractéristiques de l'eau subcritique (produit ionique, constante diélectrique) mise en œuvre en réacteurs à circulation construits dans ce but, ont permis l'hydrolyse quasi-totale de l'hémicellulose et des TAG. L'addition de CO2 et donc d'acide carbonique a eu un effet positif sur l'hydrolyse de l'hémicellulose. Les acides gras libres résultant de l'hydrolyse ont été estérifiés en ester éthyliques en présence d'une lipase en réacteur continu en milieu CO2 supercritique, avec un taux de synthèse de 95%. Les cinétiques des réactions ci-dessus d'hydrolyse et d'estérification ont été étudiées. La complexité des interactions entre les nombreux paramètres mis en jeu a conduit à appliquer des méthodes de plans d'expérience. Ces méthodes ont été validées avec succès avec les données expérimentales, montrant ainsi leur utilité dans le développement de procédés. La question importante de la solubilité des extractibles dans l'eau subcritique a été traitée et une méthode de prédiction mise au point et validée avec succès avec les données expérimentales. En conclusion, ce travail montre la possibilité d'appliquer le concept novateur de la Bioraffinerie Intégrée en réacteur continu avec des fluides sub- ou supercritique, contrairement à leur mise en œuvre actuelle en réacteur fermé, pour la production de composés commercialisables. / This work addresses the integrated biorefining concept (extraction, fractionation, separation of compounds from biomass prior to further transformation) by developing discrete units with the ultimate objective of coupling them to enable a continuous flow configuration. Due to the complexity of solid, there is a need for a sustainable and environmentally friendly pre-treatment technology. Sub-critical water has been used as a solvent for extracting natural compounds in addition to hydrolysis. This work investigated the hydrolysis of carbohydrates (rice bran) and triacylglycerols (TAG; sunflower oil) chosen as models. The attribute of subcritical water (ion product and dielectric constant) in continuous flow reactors built for the purpose, allowed almost quantitative hydrolysis of hemicellulose and TAG. The effect of adding CO2 and therefore carbonic acid was positive on the hydrolysis of hemicellulose. Further, free fatty acids were transformed to ethyl esters using lipase within continuous flow super critical CO2 resulting in 95% yield. The hydrolysis and esterification reaction kinetics were studied. To address the complex interplay between multiple processing parameters response surface methodologies (RSM) were developed. Using the empirical data the models were successfully validated, therefore showing the utility of the RSM to assist process development. The important question of solubility of extractible in subcritical water was also addressed, through the development of a prediction method, validated with experimental data. In summary this work shows the possibility of applying the innovative Integrated Biorefining concept under continuous flow conditions -instead of the current application under batch conditions- for producing valuable compounds.

Des agrégats à base des boues de phosphate de la zone de Gantour ( Youssoufia,Maroc) sont cuits à des températures comprises entre 900 et 1200°C, et examinés par différentes techniques (DRX, MEB, analyses thermique et dilatométrique, et spectroscopie d’impédance). Les propriétés physiques des agrégats (retrait, absorption d’eau et résistance à la compression) sont mesurées et corrélées, dans certains cas, aux facteurs expérimentaux(température, temps de cuisson, teneur de l’additif), et ce en utilisant la méthodologie de la recherche expérimentale.Les agrégats amendés à l’argile smectitique sont le siège de formation de la gehlénite. Dans ce cas, la fluorapatite a partiellement résisté au traitement thermique, et a été le siège d’une ségrégation localisée. Les mesures d'impédance ont bien mis en évidence l'étape principale du frittage, lequel s’est produit par écoulement de la masse fondue. En se basant sur les valeurs de la densité, les granulats cuits à 900 et à 1100°C pouvaient bien être considérés comme des agrégats légers.Les études menées sur les agrégats des mélanges : argile kaolinitique-boue, cendre boue,et argile kaolinitique-cendre-boue ont montré la présence de la labradorite, et d’une masse fondue, qui semblait se former, entre autres, de la fusion de la fluorapatite. Par ailleurs,l'utilisation de la méthodologie de la recherche expérimentale a permis d'évaluer le poids des effets des facteurs expérimentaux sur les propriétés physiques des agrégats. Des granulats légers (1,02 < densité < 2,1 g/cm3) et résistants sont préparés avec succès dans les conditions expérimentales adoptées. Les granulats ayant le meilleur rapport résistance / densité sont ceux du mélange ternaire.Concernant le volet application, les résultats ont montré que l’utilisation des agrégats en construction est possible et que l’association d’agrégats légers au sol a permis d’activer la croissance des plants de la luzerne. D’un autre côté, l'absorption du phosphore par les racines(1,45 mg/g maximum) des plantes était meilleure dans le cas du mélange contenant de l’argile. / Phosphate sludge generated from beneficiation plants of Moroccan phosphate rocks was investigated at the range [900-1200°C] by X-ray diffraction, scanning electron microscopy, thermal analysis dilatometric analysis and impedance spectroscopy. Mixtures of the phosphates ludge and amendments such as a swelling clay (up to 30 wt.% of the clay), a kaolinitic clay (up to 40 wt.% of the sludge) and a fly ash (65.5 wt.% of the ash) were investigated and their properties (shrinkage, density, water absorption and compressive strength) were measured as a function of temperature and clay addition. The results showed that gehlénite neoformed from lime of decomposed carbonates and breakdown products of clay minerals in the first mixture while labradorite/anorthite was the only neoformed phase in the other blends. Also fluoroapatite (original mineral) resisted heating until fusion in almost samples. A new approach based on the methodology of the experimental design was adopted to assess the effect of the processing factors on the studied properties. The measured properties were mainly controlled by temperature, and the effect of clay addition was less regular. Considering the mixtures densities lightweight agglomerates can be produced at specific conditions. On the other hand, the release ability of phosphorus by LWAs in the presence ofalfalfa plants has been performed. It was found that due to the release of phosphorus by soil embedded pellets the growth of alfalfa plants improved. The sintering process of blends of phosphate sludge and a naturally occurring clay material (0-30 wt.%) was investigated in the range 650-1100°C by using impedance spectroscopy. The results showed that the sintering process was effective between 750 and 1000°C and occurred by melt flow.

A estabilidade oxidativa em óleos e emulsões é influenciada pela ação simultânea de diversos fatores. Entretanto, a avaliação do efeito antioxidante de novos compostos tem sido conduzida utilizando-se valores fixos para esses fatores. Portanto, o objetivo deste estudo foi aplicar técnicas fatoriais para desenvolver modelos de oxidação lipídica nos quais os principais fatores pudessem variar simultaneamente. A oxidação de óleo de linhaça removido de seus componentes minoritários, determinada pela concentração de hidroperóxidos e malonaldeído (TBARS), foi avaliada em função da variação conjunta da temperatura (40 - 60 oC), concentração de ferro (0,0 - 1,0 mmol/L FeSO47H2O) e de ascorbil palmitato (0,0 - 1,5 mmol/L). Os maiores valores observados para os marcadores foram obtidos a 40oC, sendo altamente dependentes da relação \"ferro / ascorbil palmitato\". Adicionando-se 1,4707 mmol/L de ferro e 1,5839 mmol/L de ascorbil palmitato, a amplitude de formação de hidroperóxidos aumentou em 57%. Uma emulsão foi preparada com 1% do mesmo óleo de linhaça removido de seus componentes minoritários, utilizando-se um emulsificante aniônico sob alta pressão. A variação da temperatura, pH e concentração de ferro, cobre, ácido ascórbico, ascorbil palmitato e cloreto de sódio nos marcadores químicos da oxidação (hidroperóxidos e TBARS) foi avaliada através de um planejamento fracionário do tipo Plackett-Burman para seleção de variáveis. A seguir, o efeito das concentrações de ferro (0,0 - 1,0 mmol/L FeSO47H2O), ácido ascórbico (0,0 - 2,0 mmol/L) e pH (3,0 - 7,0) na estabilidade oxidativa das emulsões foi avaliado utilizando-se um Delineamento Composto Central. Os maiores valores dos marcadores foram obtidos adicionando-se 0,885 mmol/L de ferro e 1,700 mmol/L de ácido ascórbico à emulsão mantida a 30ºC sob pH 5,51. A atividade antioxidante de seis compostos foi avaliada em ambos os modelos (óleo puro e emulsão), sendo que uma melhor discriminação entre as amostras foi observada nos sistemas otimizados. A utilização de técnicas fatoriais mostrou-se eficiente na avaliação conjunta de vários fatores que influenciam a estabilidade oxidativa de óleos e emulsões, e proporcionou um melhor poder de discriminação na atividade antioxidante de compostos naturais e artificiais. / The oxidative stability in bulk oils and emulsions is affected by many factors. However, assessment of the antioxidant effect of new compounds has been carried out under fixed conditions. Thus, the objective of this study was to apply factorial techniques to develop lipid oxidation models in which the main factors vary simultaneously. Oxidation of flaxseed oil stripped of its minor components determined by the concentration of hydroperoxides and malonaldehyde (TBARS) was evaluated according to the combined variation of temperature (40 - 60 oC), iron concentration (0,0 - 1,0 mmol/L FeSO47H2O) and ascorbyl palmitate concentration (0,0 - 1,5 mmol/L). The highest observed values to these markers were obtained at 40oC, being greatly dependent on the \"iron / ascorbyl palmitate\" ratio. Addition of 1,4707 mmol/L of iron and 1,5839 mmol/L of ascorbyl palmitate increased the hydroperoxide formation by 57%. An emulsion was prepared with 1% of the same stripped flaxseed oil and an anionic emulsifier under high pressure. The variation of temperature, pH and iron, copper, ascorbic acid, ascorbyl palmitate and sodium chloride concentration on the chemical markers of oxidation (hydroperoxides and TBARS) was evaluated using a Plackett-Burman design to screen the variables. Following, the effect of iron concentration (0,0 - 1,0 mmol/L FeSO47H2O), ascorbyl palmitate concentration (0,0 - 2,0 mmol/L) and pH (3.0 - 7,0) on the oxidative stability of the emulsion was evaluated using a Central Composite Design. The highest observed values to these markers were obtained adding 0,885 mmol/L of iron and 1,700 mmol/L of ascorbic acid to the emulsion under 30ºC and pH 5,51. The antioxidant activity of six compounds was evaluated using both models (bulk oil and emulsion), in which a better discrimination was observed for the samples in the optimized systems. The application of factorial techniques was efficient on the joint assessment of several factors that affect the oxidative stability of oils and emulsions, and provided a better discrimination power on the antioxidant activity of natural and artificial compounds.

A oxidação lipídica é uma das causas mais importantes que levam à perda das qualidades nutricionais e sensoriais dos alimentos que possuem lipídios em sua composição, diminuindo assim sua vida de útil e provocando rejeição por parte dos consumidores. Considerando estes aspectos, a indústria de alimentos faz o uso de compostos antioxidantes, capazes de retardar a oxidação. A maioria dos antioxidantes utilizados atualmente é de origem sintética, que apresentam restrições quanto ao seu uso em alimentos que variam de país para país. Tais restrições fundamentam-se em aspectos relacionados ao impacto dos antioxidantes sintéticos sobre a saúde do consumidor. Em consequência, na última década ocorreu um aumento considerável no número de pesquisas que abordam uso de antioxidantes obtidos de fontes naturais em alimentos, a fim de identificar fontes promissoras desses compostos. Com esse objetivo, o presente trabalho avaliou a atividade antioxidante de extratos hidroalcoólicos de duas amostras de frutos de murtilla (Ugni molinae Turcz.), silvestre e a cultivar melhorada 14-4, por meio da aplicação de testes in vitro e em sistema modelo a base de óleo de soja. A aplicação da Metodologia de Superfície de Resposta permitiu a seleção da melhor condição operacional para a produção de extratos hidroalcoólicos a partir dos frutos desidratados. A condição que apresentou maior eficiência para recuperação dos compostos fenólicos foi o emprego de etanol 49,5% (v/v) a temperatura de 30ºC, sendo que para a murtilla silvestre o teor foi de 18,39 mg GAE/ g matéria seca e 26,14 mg GAE/ g matéria seca para a cultivar 14-4. As análises de ABTS e DDPH foram realizadas nos extratos produzidos nas condições otimizadas e os resultados obtidos foram 471?mol TEAC/g matéria seca de murtilla silvestre e 881,84 ?mol TEAC/g matéria seca de murtilla 14-4 para o ABTS e 229,59 ?mol TEAC/g matéria seca de murtilla silvestre e 403 ?mol TEAC/g matéria seca de murtilla 14-4 para o DPPH. Análise cromatográfica em fase gasosa acoplada a detector de massas foi realizada visando a identificação dos compostos presentes nos extratos, após derivatização das amostras. Foram identificados componentes como quercetina, epicatequina, ácido gálico, ácido benzoico e ácido hidrocafeico, que possuem atividade antioxidante comprovada. Os extratos potencialmente antioxidantes foram aplicados em sistema modelo (50, 100, 150 e 200 mg kg-1) com óleo insaturado (óleo refinado de soja, sem adição de antioxidantes sintéticos) em condições aceleradas: Teste de estufa (Schaal Oven Test) e Rancimat. No teste de Estufa e no Rancimat as concentrações que apresentaram melhor poder antioxidante foram a de 150 e 200 mg kg-1 para as duas amostras de extratos de frutos de murtilla analisadas. Os resultados de análise sensorial com provadores treinados demonstraram que não houve diferenças estatisticamente significativas entre as concentrações dos extratos adicionados ao óleo de soja submetido à oxidação em estufa, sendo que o TBHQ demonstrou a melhor aceitação. Contudo, considerando as observações feitas pelos provadores é possível afirmar que após as 96 horas de estufa, o odor de ranço foi mascarado pelo odor agradável do extrato dos frutos. / Lipid oxidation is one of the most important causes that promote the loss of nutritional and sensory qualities of foods containing lipids in their composition, thus decreasing their shelf life and causing rejection by consumers. Considering theses aspects, the food industry uses antioxidant compounds that are able to inhibit or retard oxidation. However most of antioxidants currently used are synthetic, with restrictions as to its use in lipid-based foods that vary from country to country. Such restrictions are based on aspects related to the impact of synthetic antioxidants on consumer\'s health. Due to this, in the last decade there was an increase in the number of researches that focuses on using natural sources of antioxidants, such as vegetables, fruits, among others, in food, in order to identify potential sources of antioxidants. With this objective, the present study evaluated the antioxidant activity of hydroalcoholic extracts of two varieties of murtilla\'s fruits (Ugni molinae Turcz.), wild and 14-4, through the application of in vitro assays and in a model system based on soybean oil. The application of response surfaces methodology allowed the selection of the optimal operating condition for the production of hydroethanolic extracts from dried fruit. The total phenolic compounds were determined for evaluation of extracts\' antioxidant activity and adjustment of mathematical models. The condition with the highest phenolic content was extracted using ethanol 49,5% (v/v) and temperature at 30°C, the content for the wild murtilla was 18,39 mg GAE/g dry matter and 26,14 mg GAE/g dry sample for 14-4. The ABTS and DDPH analyses were proceeded with selected optimization extracts and the results were 471?mol TEAC/g dry sample of wild murtilla and 881,84 ?mol TEAC/g dry sample of 14-4 murtilla for ABTS and 229,59 ?mol TEAC/g dry sample of wild murtilla and 403 ?mol TEAC/g dry sample of 14-4 murtilla for DDPH. The analysis by gas chromatography-mass detector was performed for the identification of compounds presents in the extracts after derivatization of the samples. Were identified compounds as quercetin, epicatechin, gallic acid, benzoic acid and hidrocafeico that have proven antioxidant activity. The extracts potentially antioxidants were applied to the model system in increasing doses (50, 100, 150 and 200 mg kg-1) with unsaturated oil (refined soybean oil without addition of synthetic antioxidants) under accelerated conditions: Oven Test (Schaal Oven Test) and Rancimat. Concentrations that better presented antioxidant power were 150 and 200 mg kg-1for both of murtilla samples. Sensory results showed that there was no statistically significant difference among the concentrations of the extracts, and TBHQ showed a better acceptance by the trained panel. However, considering the comments made by the tasters is possible to affirm that after 96 hours of oven, the rancid odor is masked by the pleasant odor of the fruit.