The ductility of Q&P 1180 steel was studied with regard to retained austenite transformation under different strain paths. Specimens were tested in uniaxial tension in a standard test frame as well as in situ in the scanning electron microscope (SEM). Then digital image correlation (DIC) was used to compute the effective strain at the level of the individual phases in the microstructure. Stretching experiments were also performed using limiting dome height (LDH) tooling, where specimens were strained in both biaxial and plane strain tension. The experiments were done incrementally, for each strain path, and the retained austenite at each level of strain was measured using electron backscatter diffraction (EBSD). Retained austenite levels in the uniaxial tension case dropped from an initial measured level of about 8% to about 2% during an initial strain increment of 0.02, but then stabilized as the specimen was strained to 0.1. In the plane strain and biaxial tension cases retained austenite also dropped significantly during an initial strain increment of about 0.04, but then continued to decrease as the specimens were strained to failure. Biaxial tension, in particular, was the most effective strain path for transforming retained austenite to martensite, resulting in a final volume fraction of 0.3% at an effective strain of 0.3. Retained austenite in the plane-strain tension case dropped at a faster rate than in the biaxial tension case, but finished at about 1% at a strain of 0.1. The greatest limit strains were seen in the biaxial tension case, which may be partly explained by the more effective conversion of retained austenite than was seen in the uniaxial tension case.

Le présent travail de thèse porte sur l‘étude de l‘effet de la texturation par Détente Instantanée Contrôlée (DIC) sur l‘opération d‘extraction solide liquide d‘oligosaccharides à partir des graines de Tephrosia purpurea et d‘anthocyanes à partir de calices de Roselle (Hibiscus sabdariffa) en vue d‘améliorer la cinétique et le rendement d‘extraction. Une analyse fondamentale a prouvé l‘importance de la diffusion du solvant dans la matrice solide et de l‘extrait dans le solvant, en tant que principal processus limitant. L‘expansion de la structure solide a donc été identifiée comme principale action devant mener à l‘intensification de l‘opération. L‘effet des paramètres opératoires de la DIC (pression de vapeur et temps de traitement thermique) a été quantifié. L‘étude a montré la capacité du traitement par DIC d‘intensifier l‘opération en termes de cinétique et de rendement d‘extraction dans les deux cas du cicéritol et du stachyose à partir des graines de Tephrosia purpurea et d‘anthocyanes à partir de calices de Roselle (Hibiscus sabdariffa). Dans le cas des oligosaccharides, le temps d'extraction a été réduit à une heure au lieu de 4h. Le rendement a été amélioré d'un facteur de 150%. Concernant les anthocyanes, le temps d‘extraction a été réduit à 3 minutes au lieu de 10 minutes et le rendement a été amélioré d‘un facteur de 120%. Une étude phénoménologique a permis de déterminer la valeur de la diffusivité d‘extraction de ces différentes molécules dans la matière première et dans les matériaux différemment traités par DIC. Les effets de la température d‘extraction et du solvant ont également été étudiés dans le cas de l‘extraction des oligosaccharides.

Le présent travail de thèse porte sur l'étude de l'impact de la texturation par DIC (Détente Instantanée Contrôlée) sur les deux opérations d'extraction d'huile et de transestérification in-situ appliquées aux graines de colza et fèves de Jatropha Curcas. Une analyse fondamentale a prouvé l'importance de la diffusion du solvant ou réactif dans la matrice solide, et permis d'identifier les processus d'intensification au travers des trois caractéristiques physiques de diffusivité effective, d'accessibilité initiale et de rendement d'extraction ; ainsi que la cinétique de transestérification in-situ et le rendement d'ester méthylique d'acides gras. Une étude phénoménologique a permis de déterminer les diverses valeurs de ces caractéristiques en fonction des paramètres opératoires DIC (pression de vapeur d'eau saturée P et temps de traitement t).Dans le cas d'extraction, la diffusivité effective (Deff) de produits traités par DIC peut atteindre 8,01 10-12 m2/s contre 0,715 10-12 m2/s pour le colza non traité et 5,90 10-12 m2/s contre 2,42 10-12 m2/s pour le jatropha non traité. Le taux d'accessibilité initiale de produits traités par DIC peut atteindre 80,53% contre 26,71% pour le colza non traité et 92,58% contre 75,91% pour le jatropha non traité. Au plan du rendement, la DIC a pu impliquer un rendement de 153% pour le colza et 112% pour le jatropha.Dans le cas de la transestérification in-situ, les rendements d'esters méthyliques d'acides gras totaux (FAME total) obtenus pour les produits traités par DIC sont systématiquement supérieurs à ceux de la matière première non traitée par DIC pour les deux cas de colza et de jatropha. Le temps de réaction a été réduit à 30 - 45 minutes contre 120 minutes pour le produit non traité par DIC (cas de colza) et à 15 minutes au lieu de 60 minutes pour le produit non traité par DIC (cas de fèves de jatropha).

We will propose a random changepoint model for the analysis of longitudinal CD4 and CD8 T-cell counts, as well as viral RNA loads, for HIV infected subjects following highly active antiretroviral treatment. The data was taken from two studies, one of the Aids Clinical Group Trial 398 and one performed by the Terry Beirn Community Programs for Clinical Research on AIDS. Models were created with the changepoint following both exponential and truncated normal distributions. The estimation of the changepoints was performed in a Bayesian analysis, with implementation in the WinBUGS software using Markov Chain Monte Carlo methods. For model selection, we used the deviance information criterion (DIC), a two term measure of model adequacy and complexity. DIC indicates that the data support a random changepoint model with the changepoint following an exponential distribution. Visual analyses of the posterior densities of the parameters also support these conclusions.

There may be several mechanisms that drive observed interactions between plants and pollinators in an ecosystem, many of which may involve trait matching or trait complementarity. Hence a model of insect species activity on plant species should be represented as a mixture of these linkage rules. Unfortunately, ecologists do not always know how many, or even which, traits are the main contributors to the observed interactions. This thesis proposes the Latent Dirichlet Allocation (LDA) model from artificial intelligence for modelling the observed interactions in an ecosystem as a finite mixture of (latent) interaction groups in which plant and pollinator pairs that share common linkage rules are placed in the same interaction group. Several model selection criteria are explored for estimating how many interaction groups best describe the observed interactions. This thesis also introduces a new model selection score called ``penalized perplexity". The performance of the model selection criteria, and of LDA in general, are evaluated through a comprehensive simulation study that consider networks of various size along with varying levels of nesting and numbers of interaction groups. Results of the simulation study suggest that LDA works well on networks with mild-to-no nesting, but loses accuracy with increased nestedness. Further, the penalized perplexity tended to outperform the other model selection criteria in identifying the correct number of interaction groups used to simulate the data. Finally, LDA was demonstrated on a real network, the results of which provided insights into the functional roles of pollinator species in the study region.

Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-08-31T14:06:01Z No. of bitstreams: 1 Tese_Fernanda_Revisão Final.pdf: 5433077 bytes, checksum: 30cfa44a7a7312cf3778c6606c92d4ff (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2016-09-02T16:14:00Z (GMT) No. of bitstreams: 1 Tese_Fernanda_Revisão Final.pdf: 5433077 bytes, checksum: 30cfa44a7a7312cf3778c6606c92d4ff (MD5) / Made available in DSpace on 2016-09-02T16:14:00Z (GMT). No. of bitstreams: 1 Tese_Fernanda_Revisão Final.pdf: 5433077 bytes, checksum: 30cfa44a7a7312cf3778c6606c92d4ff (MD5) / Braskem / A nafta e o etanol são matérias-primas importantes da indústria petro e alcoolquímica respectivamente, tendo o eteno e o propeno como seus principais derivados da primeira geração. A eficiência desses processos produtivos pode ser comprometida por traços de compostos carbonílicos e carboxílicos voláteis neles contidos. Tal contaminação pode afetar, por exemplo, a qualidade de embalagens de alimentos, uma vez que tais derivados são compostos precursores para produção dos plásticos utilizados nessas embalagens. No presente trabalho foram desenvolvidos métodos simples para a determinação de compostos carbonílicos e carboxílicos em matrizes líquidas e gasosas derivadas do petróleo por cromatografia em fase gasosa com sistema de detecção por ionização em chama (CG/DIC), cromatografia líquida de alta eficiência (CLAE), cromatografia gasosa acoplada à espectrometria de massas (CG/EM) e CG/DIC acoplado a sistema analítico Dean Switch. Para a determinação dos ácidos acético, propanóico, butanóico e pentanóico em matrizes líquidas e gasosas, a cromatografia em fase gasosa com sistema de detecção por ionização em chama por injeção direta utilizando coluna cromatográfica capilar FFAP (for free fatty acids) foi a técnica mais adequada. O desvio padrão relativo (RSD) obtido foi de 5,6% a 6,5% para 2 g.g-1 em n-hexano, 2,1% a 5,8% para 10 g.g-1 em etanol e 4,2 a 7,7% para 10 g.g-1 em propeno. Os limites de detecção encontrados foram de 0,036 - 0,12 g.g-1 em hidrocarbonetos gasosos (eteno e propeno), 0,047 - 0,16 g.g-1 em matrizes puras de hidrocarbonetos líquidos (n-hexano) e 0,08 – 0,18g.g-1 em matriz alcoólica (etanol). Para a determinação do teor de ácidos carboxílicos em matrizes complexas como a nafta, a CLAE foi a técnica utilizada, precedida de extração líquido- Fernanda Seabra Vianna Vieira 11/238 líquido sob condições controladas. O RSD obtido foi de 5,5% a 7,7% para 40 g.g-1 e o limite de detecção médio foi de 4 g.g-1. Para a determinação dos teores dos compostos carbonílicos (aldeídos e cetonas) em matrizes líquidas e gasosas, a cromatografia empregando o sistema analítico comercial Dean Switch mostrou-se como a mais adequada. Valores de RSD da ordem de 2,6% a 3,5% para propeno; 0,9% a 1,4% para n-hexano e 1,6% a 2,6% para a nafta em padrões contendo respectivamente 2 g.g-1, 2 g.g-1 e 10 g.g-1. Os limites de detecção de 0,033 - 0,084 g.g-1 (propeno), 0,021- 0,09 g.g-1 (n-hexano) e 0,049 - 0,26 g.g-1 (nafta) confirmam a eficiência de detecção e quantificação para matrizes de hidrocarbonetos de origem petroquímica tipicamente inferiores a 10 g.g-1. A partir dos resultados obtidos foi feita uma avaliação comparativa entre as técnicas, evidenciando as vantagens e desvantagens de cada método para cada aplicação específica. / Although metals and nitrogen & sulfur compounds have been the main concern in the petroleum industry, issues on the harmful effects on catalysts poisoning and products contamination of other contaminants such as oxygen- containing compounds have been raised. Trace amounts of carbonyl and carboxyl compounds in petroleum products can lead to catalyst poisoning and overall decrease on reactions yield. Furthermore, oxygenates may be present in the polyethylene and polypropylene resins, affecting the quality of the food packagings obtained from these materials. The available literature on C1-C5 aldehydes, ketones and carboxylic acids determination in petroleum products such as naphtha, ethylene and propylene is quite rare. Therefore, in the present work we intend to review the analytical approaches that could be applied to such analytical purpose, present the features of each potential technique and some studies performed on somewhat similar matrices. For acetic, propanoic, butanoic and pentanoic acids determination in liquid and gas matrices, gas chromatography with flame ionization detector and FFAP for free fatty acids capillary column was the most appropriate method. The relative standard deviation (RSD) was 5.6% to 6.5% in the range of 2 g.g-1 in n-hexane, 2.1% to 5.8% in the range of 10 g.g-1 in ethanol and 4.2 to 7.7% in the range of 10 g.g-1 in propylene. The detection limits found were from 0.036 to 0.12 g.g-1 in hydrocarbons gases (ethylene and propylene), 0.047 to 0.16 g.g-1 in pure liquid hydrocarbons (n-hexane) and 0.08 to 0.18 g.g-1 in alcoholic matrices (ethanol). For carboxylic acid determination in complex matrices such as naphtha, the HPLC technique was used, preceded by liquid-liquid extraction under Fernanda Seabra Vianna Vieira 9/238 controlled conditions. The RSD obtained was 5.5% to 7.7% in the range of 40 g.g-1 within the average detection limit was 4 g.g-1. For carbonyl compounds (aldehydes and ketones) determination in gas and liquid matrices, the commercial analytical system Dean Switch proved to be the most appropriate. RSD values of around 2.6% to 3.5% for propylene; 0.9% to 1.4% for n-hexane and 1.6% to 2.6% for naphta in standards containing respectively 2 g.g-1, 2 g.g-1 and 10 g.g-1. The detection limit of 0.033 to 0.084 g.g-1 (propylene), 0.021 to 0.09 g.g-1 (n-hexane) and 0.049 to 0.26 g.g-1 (naphtha) confirm the efficiency of detection and quantification for range of hydrocarbons of petrochemical origin typically less than 10 g.g-1.

Le béton est un des matériaux de construction les plus répandus. Néanmoins son comportement en traction dynamique n’est pas parfaitement connu. C’est afin de mieux concevoir les structures en béton et de prédire leur ruine dans le cadre d’éventuels accidents industriels qu’il est nécessaire de connaître sa résistance. Cette dernière évolue en fonction des différentes sollicitations auxquelles le béton peut être soumis. Afin de caractériser la résistance en traction d’un béton de type R30A7, ainsi que son évolution en fonction de la vitesse de déformation, différents essais de flexion trois points ont été réalisés que cela soit en statique ou en dynamique. Un dispositif conforme aux normes en vigueur en statique ainsi que le dispositif dynamique des barres de Hopkinson ont été utilisés. Ce dernier permet de réaliser des essais dynamiques en mesurant le chargement et la vitesse en entrée comme en sortie. En plus de l’instrumentation traditionnelle, les essais ont été suivis à l’aide d’une caméra rapide afin de réaliser des mesures de champ de déplacement à l’aide de la corrélation d’images numériques. Des outils utilisant ces champs de déplacement ont été créés afin de suivre au mieux l’apparition et l’évolution de la fissure. L’ensemble de ces moyens de mesures permettent, avec l’aide de différentes modélisations, qui prennent en compte ou non l’endommagement des éprouvettes, de caractériser l’évolution de la contrainte de rupture en traction en fonction de la vitesse de déformation. Ce travail a mis en avant le fait qu’ignorer l’endommagement du matériau lors d’essais dynamiques augmente de manière non négligeable la valeur de la contrainte à rupture déduite des essais. / The concrete is one of the most widely used constructional materials. However, its tensile behavior in dynamic is yet not perfectly known. In order to design concrete structures and predict their collapse in the case of industrial accidents, it is mandatory to know its tensile strength. This property depends on the different solicitations to which the concrete can be exposed. In order to characterize the tensile strength of a R30A7 concrete and its dependence on the strain rate, three points bending tests are performed in static and dynamic cases. For this purpose, the most recent standards are used in the static tests. The dynamic ones are carried out with the split Hopkinson pressure bars. This device allows to perform dynamic tests with both the speed and effort loading measurements. Moreover a high speed camera is used to record these experiments in order to acquire full-field displacement measurements with the help of the digital image correlation. Tools using these fields are created to detect the apparition of the crack in one hand, and to follow the crack propagation in the other hand. All these experimental devices and the use of different models, some of which take in account the sample damage, make it possible to determinate the evolution of the tensile strength depending on the strain rate. This work brings forward the fact that ignoring the material damage increases the tensile strength obtain from the tests.

As anormalidades hematológicas de origem paraneoplásica são identificadas em diversos tipos de neoplasias que acometem cães e gatos. Nas neoplasias mamárias em cadelas, já foram identificadas anormalidades relacionadas com a coagulação, onde verificou-se que a coagulação intravascular disseminada (CID) clínica e subclínica pode estar presente em 83% das cadelas com carcinoma mamário. Na medicina humana, é dada relevância à investigação de tais alterações uma vez que são fatores indicadores de prognóstico do câncer. Enquanto isso, na medicina veterinária, são escassos os estudos que relacionam as alterações hematológicas com o tipo tumoral, estadiamento e determinação de prognóstico. O objetivo do presente estudo foi realizar a avaliação hematológica, bioquímica e da hemostasia de cadelas acometidas por neoplasia mamária para identificar a alteração mais frequente, além de relacionar as anormalidades com o estadiamento tumoral. Para isso, foram utilizadas 25 cadelas atendidas pelo Grupo de Estudos em Oncologia em pequenos animais (ONCOVET) do Hospital de Clínicas Veterinárias da UFRGS (HCV-UFRGS) durante o período de 4 meses. Foi realizado coleta de sangue para hemograma, contagem de plaquetas, bioquímica sérica (albumina, ALT, cálcio, creatinina, FA, glicose, ureia) e teste de coagulação que constou de TP (tempo de protrombina), TTPa (tempo de tromboplastina parcial ativada), TT (tempo de trombina), fibrinogênio e mensuração do dímero-D. O estadiamento tumoral foi obtido através do exame físico e do resultado da biopsia das mamas. As anormalidades encontradas incluíram anemia, leucocitose neutrofílica, monocitose, eosinofilia, trombocitose, hipoalbuminemia, hipocalcemia, hipoglicemia e diminuição dos níveis de ureia sanguínea. Entretanto, essas alterações não foram relacionadas diretamente com a progressão tumoral, uma vez que não houve diferença entre os grupos avaliados. Apenas as variáveis RDW e ALT apresentaram relação significativa entre os grupos, contudo, sem relevância clínica. No teste de coagulação, houve diferença significativa entre os grupos apenas no TT e fibrinogênio, que foi relacionado com o estadiamento tumoral. / Hematological abnormalities of paraneoplastic origin are identified in several types of cancers that affect dogs and cats. In dogs with mammary neoplasms, abnormalities associated with coagulation have been identified, and verified that disseminated intravascular coagulation (DIC) clinical and subclinical may be present in 83% of dogs with mammary carcinoma. In human medicine, research in this field has been relevant since those factors are indicators of cancer prognosis. Meanwhile, in veterinary medicine, there are few studies that relate hematological changes with tumor type, staging and determination of prognosis. The aim of this study was to evaluate the hematological, biochemical and hemostathic abnormalities in bitches affected by mammary cancer to identify the most frequent alteration and associate with tumor staging. For this, 25 bitches attended by the Oncology Study Group in small animals (ONCOVET) of the Veterinary Hospital of UFRGS (HCV-UFRGS) for the period of 4 months were used. Blood collection for complete blood count, platelet count, serum biochemistry (albumin, ALT, calcium, creatinine, ALP, glucose, urea) and coagulation test that consisted of PT (prothrombin time), aPTT (activated partial thromboplastin time), TT (thrombin time), fibrinogen and D-dimer measurement were performed. Tumor staging was obtained by physical examination and the results of the biopsy of the breast. The abnormalities found included anemia, neutrophilic leukocytosis, monocytosis, eosinophilia, thrombocytosis, hypoalbuminemia, hypocalcemia, hypoglycemia and decreased levels of urea. However, these changes were not associated directly with tumor progression, since there was no difference among the groups. Only the RDW and ALT variables was associated significantly between the groups, however, with no clinical relevance. In the coagulation test, there was significant difference between the groups only in TT and fibrinogen, which was associated with tumor staging.

Dans le séchage des fruits et légumes, beaucoup de questions non résolues subsistent. Le «Swell-drying» est un procédé de séchage couplant une étape de déshydratation par air chaud à la texturation par Détente Instantanée Contrôlée (DIC). Dans le cadre de ce travail de recherche, la carotte et la pomme sont utilisées comme aliment modèle pour le traitement de la plupart des végétaux. La littérature scientifique sur le séchage des agromatériaux est unanime sur l’effet positif de la température de l'air, l’effet négatif de l'humidité relative de l'air et de l'épaisseur vis-à-vis du temps de séchage. Cependant, malgré un nombre important d’études, des conclusions contradictoires sont notées en termes de corrélations entre la cinétique de séchage et la vitesse de l'air qui, selon certains auteurs, n’entraîne aucune modification du séchage; alors que certains travaux ont tenté d'établir des modèles empiriques entre la diffusivité effective et la vitesse de l'air ; ce qui est fondamentalement erroné. L’objectif de cette thèse est d’analyser les phénomènes de transfert pendant le processus du séchage et d'identifier le phénomène limitant entre les transferts internes et externes. Ce travail aboutir à l’identification de la vitesse critique de l'air CAV capable de rendre la diffusion interne de l’eau comme phénomène limitant. La CAV doit donc dépendre de la diffusivité effective et de la taille du produit. À partir de résultats expérimentaux qui couvrent de larges plages de température d’air, de teneur en eau, et de taux d'expansion absolu, un modèle empirique a été établi. / Great research works support the sector of drying of fruits and vegetables in a number of ways. Each year, experimental results and mathematical modelling try through conventional and innovative technological processes to protect agricultural products from seasonality and variability in the market prices. Nonetheless, there still exist considerable issues to improve and control this strategic agricultural sector. Swell-drying is very relevant drying process coupling hot air dehydration with Instant Controlled Pressure Drop (DIC). In the present work, carrot and apple were used as a fruit and vegetable model. Scientific literature on drying is unanimous that the drying time decreases with increasing air temperature, decreasing air relative humidity, and reducing thickness. However, the effect of airflow velocity leads to contradictory conclusions. Some authors have claimed that it does not trigger any modification of drying; while some articles tried to establish empirical models of the effective diffusivity versus airflow velocity; what is fundamentally erroneous. This thesis aims at analyzing external and internal transfer phenomena during drying. So, it was possible to recognize the Critical Airflow Velocity CAV depending on the effective diffusivity and the product size, to have the internal water transfer as the limiting phenomenon. From experimental results, an empirical model was established between the effective moisture diffusivity and airflow temperature, water content, and absolute expansion ratio.

Dans cette thèse, nous nous intéressons à la microscopie DIC (Differential interference contrast) en couleur. L’imagerie DIC est reconnue pour produire des images à haut contraste et à haute résolution latérale. L'un de ses inconvénients est que les images observées ne peuvent pas être utilisées directement pour l'interprétation topographique et morphologique, car les changements de phase de la lumière, produits par les variations de l'indice de réfraction de l'objet, sont cachés dans l'image d'intensité. Il s’agit donc d’un problème de reconstruction de phase. Nous présentons un modèle de formation d'image pour la lumière polychromatique, et décrivons de manière détaillée la réponse impulsionnelle du système. Le problème de la reconstruction de phase est abordé sous l’angle d’un problème inverse par minimisation d’un terme d’erreur des moindres carrés (LS) non linéaire avec un terme de régularisation préservant les discontinuités, soit par le potentiel hypersurface (HS), soit par la variation totale (TV). Nous étudions les propriétés des fonctions objectives non convexes résultantes, prouvons l'existence de minimisateurs et proposons une formulation compacte du gradient permettant un calcul rapide. Ensuite, nous proposons des outils d'optimisation efficaces récents permettant d'obtenir à la fois des reconstructions précises pour les deux régularisations lisse (HS) et non lisse (TV) et des temps de calculs réduits. / In this dissertation we address the problem of estimating the phase from colorimages acquired with differential–interference–contrast (DIC) microscopy. This technique has been widely recognized for producing high contrast images at high lateral resolution. One of its disadvant ages is that the observed images cannot be easily used for topographical and morphological interpretation, because the changes in phase of the light, produced by variations in the refractive index of the object, are hidden in the intensity image. We present an image formation model for polychromatic light, along with a detailed description of the point spread function (PSF). As for the phase recovery problem, we followed the inverse problem approach by means of minimizing a non-linear least–squares (LS)–like discrepancy term with an edge–preserving regularizing term, given by either the hypersurface (HS) potential or the total variation (TV) one. We investigate the analytical properties of the resulting objective non-convex functions, prove the existence of minimizers and propose a compact formulation of the gradient allowing fast computations. Then we use recent effective optimization tools able to obtain in both the smooth and the non-smooth cases accurate reconstructions with a reduced computational demand. We performed different numerical tests on synthetic realistic images and we compared the proposed methods with both the original conjugate gradient method proposed in the literature, exploiting a gradient–free linesearch for the computation of the steplength parameter, and other standard conjugate gradient approaches.