Esta dissertação investiga o comportamento linguístico de crianças brasileiras entre 4;0 e 6;11 anos de idade, acerca da produção de orações relativas de objeto direto e de objeto preposicionado. Segundo Friedmann, Belletti e Rizzi (2009), essa dificuldade existe devido ao traço [+NP] presente no sujeito da relativa e no núcleo relativizado. Para os autores, a gramática infantil computa o sujeito da relativa como um elemento interveniente que impede a relativização do objeto, resultando em uma violação semelhante à Minimalidade Relativizada (Rizzi, 1990). Por outro lado, estudos experimentais como o de Gennari e Macdonald (2008) indicam que essa dificuldade está ausente em relativas de objeto contendo um sujeito animado e um núcleo relativizado inanimado. Partindo desses estudos, desenvolvemos uma tarefa de produção eliciada com pares de figuras. Em nossos materiais, controlamos o traço de animacidade do sujeito da relativa e do núcleo relativizado, de modo a observar quais configurações de animacidade resultam em uma maior dificuldade para as relativas de objeto. Nossos resultados sugerem que as relativas de objeto direto mais difíceis contêm um sujeito inanimado. Isto ocorre uma vez que esta posição sintática é comumente preenchida por um argumento animado (Becker, 2014). O frequente uso de estratégias de esquiva nessas relativas indica que animacidade possui um papel determinante para facilitar ou dificultar a produção de relativas de objeto direto. No que diz respeito às relativas de objeto preposicionado, nossos resultados indicam que todas as configurações do traço de animacidade foram difíceis para nossos sujeitos de pesquisa, não sendo determinante a configuração de animacidade nessas relativas. Sugerimos que um conjunto de fatores pode estar envolvido para a dificuldade observada nessas construções: a ausência de relativas com pied-piping preposicional na fala dos adultos; a maior simplicidade derivacional em relativas preposicionadas com um resumptivo nulo ou pronunciado (Roeper (2003); Lessa de Oliveira (2008)); as relativas com pied-piping preposicional dependem de seu ensino formal (Corrêa (1998); Guasti e Cardinaletti (2003)). / This dissertation investigates the linguistic behavior of Brazilian children aged between 4;0 and 6;11, in relation to the production of direct object and prepositional object relative clauses. According to Friedmann, Belletti and Rizzi (2009), such difficulty arises due to the [+NP] feature present in the relative clause subject and the relativized head. To the authors, the child grammar takes the relative subject as an intervening element that hampers the relativization of the object, resulting in a violation resembling Relativized Minimality (Rizzi, 1990). On the other hand, experimental studies like Gennari and Macdonald (2008) indicate that such difficulty is absent in object relatives featuring an animate subject and an inanimate relativized head. Based on these studies, we designed an elicited production task with pairs of pictures. In our experimental material, we controlled the animacy feature in both the relative subject and the relativized head, so as to check which animacy configurations render the object relatives more difficult. Our results suggest that direct object relatives become more difficult when they feature an inanimate subject. That happens because the subject position is typically filled by an animate argument (Becker, 2014). The frequent use of avoidance strategies in these relatives indicates that animacy plays a determining role in facilitating or hindering the production of direct object relatives. Regarding the prepositional object relatives, our results indicate that all the animacy configurations were difficult for our research subjects, so that animacy does not play a determining role in the production of these relatives. We suggest that a number of things might be involved in the difficulty observed in these constructions: the absence of relatives featuring prepositional pied-piping in the speech of adults; the bigger derivational simplicity in prepositional relatives with a null or a pronounced resumptive (Roeper (2003); Lessa de Oliveira (2008)); relatives featuring prepositional pied-piping require formal learning (Corrêa (1998); Guasti e Cardinaletti (2003)).

A obesidade na infância e adolescência tem aumentado de forma bastante acentuada, e quando observada nos primeiros anos de vida leva um maior risco para hipercolesterolemia, hipertrigliceridemia e alterações cardiovasculares na vida adulta. Uma correlação positiva tem sido observada entre a BMI (Body Mass Index, ou índice de massa corporal) e alterações metabólicas e hematológicas, implicando em alterações na capacidade de cicatrização, na defesa imunológica e celular e no desenvolvimento de diferentes patologias. O objetivo deste estudo foi avaliar os efeitos das fases iniciais da hipercolesterolemia, ou seja, nas idades infantil e juvenil e com pequeno aumento de colesterol, sobre os tecidos bucais e a capacidade de cicatrização. A Ratos Wistar (40g de peso) foi oferecido uma ração preparada com 1% de aumento (em peso) de colesterol + 20% de gordura (óleo de soja) por um período de 2 e 6 semanas para avaliação dos tecidos bucais. Após 2 semanas do uso da ração enriquecida com colesterol foram realizadas feridas cirúrgicas no dorso dos animais para avaliação da cicatrização. Ao final dos tratamentos propostos, os animais foram sacrificados, e colhidas as peças utilizadas (sangue, pele, língua, palatos e região gengival). O sangue coletado foi centrifugado e o soro foi utilizado para avaliação das lipoproteínas - colesterol total, HDL, LDL, VLDL e triglicérides em espectrofotômetro de absorbância. As peças colhidas foram levadas para fixação e descalcificação de acordo com a necessidade, processadas para inclusão em parafina, cortadas com 6 µm de espessura, montadas em lâminas de vidro e coradas com hematoxilina e eosina. Essas peças foram utilizadas para avaliação histológica dos tecidos e do processo de cicatrização, por meio de técnicas morfométricas. Os dados colhidos foram apresentados em valores médios, e as diferenças analisadas por testes estatísticos adequados para a comparação entre as amostras. Nossos resultados mostram que a hipercolesterolemia provocou alterações em tecidos epiteliais e que esses efeitos parecem ser progressivos, ou seja, se tornam mais expressivos com o uso continuado de alimentação com índice de colesterol aumentado, e que existe um aparente atraso no processo de cicatrização nos indivíduos que utilizam dieta hipercolesterolêmica. Consideramos que essas alterações podem tornar esses indivíduos mais suscetíveis a alterações bucais e prejudicar as reações teciduais frente a injúrias, o que pode ser preocupante durante um tratamento odontológico, principalmente cirúrgico mas também em situações de reabilitação oral ou em tratamentos odontológicos de rotina. / Obesity in childhood has becoming a concern. Obesityy is associated with increased triglycerides, decreased high-density lipoprotein cholesterol levels, and increased low-density lipoprotein cholesterol and may lead to increased risk for hypercholesterolemia and cardiovascular complications in adult life. Clinical symptoms and signs of elevated cholesterol levels do not occur until adulthood, but subclinical aspects may be observed in children and adoslecentes. There are no studies on the effects of hypercholesterolemia in children, adolescents or in adults on oral tissues. We propose to study the influence of early age hypercolesterolemia in epithelial oral tissues and on wound healing. Male albino Wistar rats (40g) received enriched cholesterol diet (1%) for 2 and six weeks for epithelial evaluation. After 2 weeks, one control group (receiving standard pellet diet) and treated (hypercholesterolemic diet) received surgical wounds at the dorsum. Animals were sacrifed 1, 3 and 7 days after surgery. At the end of both periods (2 and 6 weeks) animals were sacrificed for epithelial evaluation. At the sacrifice time, serum were collected for evaluation of triglycerides, total cholesterol, HDL, LDL and VLDL. Were collected skin, tongue, palate and gingival tissues. Skin samples were also used for evaluation of the wound healing. All the observation were made at light microscopy. Data were statistically analysed by Mann Whitney U test for comparison between two samples. P[U] ≤0.05 were considered statistically significant. The enriched cholesterol diet significantly increased the total cholesterol, triglycerides, LDL and VLDL plasma content, and the study provide support for the hypothesis that hypercholesterolemia may be associated with deficiencies in the wound healing process. An important clinical implication of this study is the identification of alterations epithelium on oral tissues and in early phases of wound healing associated with subclinical but important alterations in cholesterol levels.

Cette thèse a pour objectif l’étude et la mise au point d’un procédé de fabrication, par cristallisation, de sel thermal enrichi en magnésium, à partir d’eaux minérales naturelles chlorurées sodiques fortes. Un modèle dynamique a d’abord été développé pour la simulation du procédé. Ce modèle est basé sur la description des phénomènes physico-chimiques intervenant dans les équilibres thermodynamiques multiphasiques (liquide, vapeur, solides). Puis, un pilote de laboratoire a été mis en place pour vérifier la faisabilité du procédé et valider le modèle développé. Le pilote proposé est constitué de deux réacteurs en série entre lesquels est placé un système de filtration. Une étude expérimentale et par modélisation du procédé avec l’eau thermale de Salies-de-Béarn a ensuite été réalisée. Cette étude montre qu’il est possible de produire un sel thermal ou une eau-mère naturellement enrichis en magnésium. / The aim of this thesis is the study and the development of a production process, by cristallization, of thermal salt enriched in magnesium, from highly chlorinated natural waters. At first, a dynamic model was developed for the process simulation. This model is based on the description of physical-chemical phenomena occurring in multiphase thermodynamic equilibrium (liquid, vapor, solids). Then, a laboratory pilot was set up to check the process feasibility and to validate the developed model. The proposed pilot is a series of two reactors between which is placed a filtration system. Finally, an experimental and modeling study of the process has been realized with thermal water of Salies-de-Béarn as raw-material. This study shows that it is possible to produce a thermal salt or mother liquor naturally enriched in magnesium.

High levels of personal car use have negative effects on the environment and on human health. This thesis presents four empirical studies that aimed to develop our knowledge of personal travel choices, focussing on the malleability of attitudes and their sensitivity in relation to specific contexts and goals. The first study (Chapter 2) presents a systematic review and meta-analysis of mechanisms of travel mode choice. The study provides a comprehensive overview of antecedents of car use and non-car use, including sub-group analyses of different contextual factors. Results also highlight the need for standardised measures and consideration of implicit thought processes. The second study (Chapter 3) employs a repertory grid technique to elicit perceptions of seven different transport modes from high mileage car users and non-car users. Comparisons between car users and non-car users highlight potentially effective and ineffective intervention targets. Findings show how sustainable transport might be promoted amongst a portfolio of travel choices. The third study (Chapter 4) utilises qualitative methods to explore the extent to which individuals’ attitude expressions are changeable. The study demonstrates that all participants hold ambivalent and conflicting attitudes, highlighting specific situations in which those attitudes are more likely to be unstable. Two related priming experiments are presented in the final empirical chapter (Chapter 5). Both use survey methodology to investigate whether manipulating the salience of car-use-incongruent goals can lead to more positive attitudes towards and increased willingness to use non-car travel modes. The study confirms that people who are motivated to make changes are a potentially optimal target group for interventions based on subliminal messages. Overall, the research presented in this thesis introduces context sensitivity into the transport literature and offers novel insights into perceptions of a range of travel modes. Recommendations include relevant avenues for future research, findings are discussed in light of implications for transport policy and practice.

Esta dissertação investiga o comportamento linguístico de crianças brasileiras entre 4;0 e 6;11 anos de idade, acerca da produção de orações relativas de objeto direto e de objeto preposicionado. Segundo Friedmann, Belletti e Rizzi (2009), essa dificuldade existe devido ao traço [+NP] presente no sujeito da relativa e no núcleo relativizado. Para os autores, a gramática infantil computa o sujeito da relativa como um elemento interveniente que impede a relativização do objeto, resultando em uma violação semelhante à Minimalidade Relativizada (Rizzi, 1990). Por outro lado, estudos experimentais como o de Gennari e Macdonald (2008) indicam que essa dificuldade está ausente em relativas de objeto contendo um sujeito animado e um núcleo relativizado inanimado. Partindo desses estudos, desenvolvemos uma tarefa de produção eliciada com pares de figuras. Em nossos materiais, controlamos o traço de animacidade do sujeito da relativa e do núcleo relativizado, de modo a observar quais configurações de animacidade resultam em uma maior dificuldade para as relativas de objeto. Nossos resultados sugerem que as relativas de objeto direto mais difíceis contêm um sujeito inanimado. Isto ocorre uma vez que esta posição sintática é comumente preenchida por um argumento animado (Becker, 2014). O frequente uso de estratégias de esquiva nessas relativas indica que animacidade possui um papel determinante para facilitar ou dificultar a produção de relativas de objeto direto. No que diz respeito às relativas de objeto preposicionado, nossos resultados indicam que todas as configurações do traço de animacidade foram difíceis para nossos sujeitos de pesquisa, não sendo determinante a configuração de animacidade nessas relativas. Sugerimos que um conjunto de fatores pode estar envolvido para a dificuldade observada nessas construções: a ausência de relativas com pied-piping preposicional na fala dos adultos; a maior simplicidade derivacional em relativas preposicionadas com um resumptivo nulo ou pronunciado (Roeper (2003); Lessa de Oliveira (2008)); as relativas com pied-piping preposicional dependem de seu ensino formal (Corrêa (1998); Guasti e Cardinaletti (2003)). / This dissertation investigates the linguistic behavior of Brazilian children aged between 4;0 and 6;11, in relation to the production of direct object and prepositional object relative clauses. According to Friedmann, Belletti and Rizzi (2009), such difficulty arises due to the [+NP] feature present in the relative clause subject and the relativized head. To the authors, the child grammar takes the relative subject as an intervening element that hampers the relativization of the object, resulting in a violation resembling Relativized Minimality (Rizzi, 1990). On the other hand, experimental studies like Gennari and Macdonald (2008) indicate that such difficulty is absent in object relatives featuring an animate subject and an inanimate relativized head. Based on these studies, we designed an elicited production task with pairs of pictures. In our experimental material, we controlled the animacy feature in both the relative subject and the relativized head, so as to check which animacy configurations render the object relatives more difficult. Our results suggest that direct object relatives become more difficult when they feature an inanimate subject. That happens because the subject position is typically filled by an animate argument (Becker, 2014). The frequent use of avoidance strategies in these relatives indicates that animacy plays a determining role in facilitating or hindering the production of direct object relatives. Regarding the prepositional object relatives, our results indicate that all the animacy configurations were difficult for our research subjects, so that animacy does not play a determining role in the production of these relatives. We suggest that a number of things might be involved in the difficulty observed in these constructions: the absence of relatives featuring prepositional pied-piping in the speech of adults; the bigger derivational simplicity in prepositional relatives with a null or a pronounced resumptive (Roeper (2003); Lessa de Oliveira (2008)); relatives featuring prepositional pied-piping require formal learning (Corrêa (1998); Guasti e Cardinaletti (2003)).

Dans le contexte du développement durable, et dans un objectif de limitation de l’impact environnemental, le recours à des sols fins prend une place croissante dans la construction d’ouvrages en terre. Mais la maîtrise de ces matériaux amène au cours de l’exécution des difficultés lors du compactage, telles que le feuilletage et le matelassage. Au sein du projet ANR TerreDurable, cette thèse vise à l’étude du compactage, plus particulièrement pour les marnes proches de la saturation. Le programme d’essais se base principalement sur les observations apportées par les praticiens (Vinci Construction Terrassement, Valerian, Egis Géotechnique), pour parvenir à des essais mettant en évidence difficultés et mauvais usages rencontrés. Après une discussion sur l’effet des méthodes de contrôle de succion sur la nucléation dans les sols fins, l’étude porte sur une planche de compactage in situ. Elle s’articule autour de 4 paramètres : teneur en eau, mouture, type de compacteur et énergie de compactage. Ces variations mènent à la réalisation de 24 plots sortants parfois du cadre règlementaire, incarné en France par le Guide des Terrassements Routiers (GTR). Une fois terminés, et après des observations visuelles, les plots subissent carottages et pénétromètres dynamiques pour évaluer l’état et la réponse hydromécanique du matériau. Les mesures recueillies permettent de fournir des informations quant aux bonnes pratiques de compactage, mais aussi vis-à-vis des variables d’état du sol selon le jeu de paramètre. Dans un deuxième temps, l'effet de la préparation du matériau est étudié dans la cadre d'essais Proctor et IPI. Le matériau de chaque essai est alors exploité pour la réalisation de courbes de retentions dans le domaine quasi saturé. Toutes ces mesures sont alors comparées à la planche, de manière à cadrer les essais de cette dernière et confirmer les observations faites en première instance. Pour finir, une cellule triaxiale de révolution est développée dans l'objectif d’étudier l’évolution des variables d’état du sol au cours du compactage. Elle présente un tensiomètre à sa base, mais aussi des fenêtres planes en plexiglas pour permettre l’utilisation de la corrélation d’images pour l’estimation des changements de volume. Ces fenêtres ont pour objectif de limiter les déformations optiques et faciliter la mesure. La conception et la calibration de la cellule sont présentées, tout en mettant en avant sa précision. Sont alors réalisés les premiers essais de reproduction du compactage, basés sur des références in situ. Malgré les difficultés rencontrées pour simuler les passes d’un compacteur au sein de la cellule, les essais apportent des éléments de réflexion quant à l’effet de ce dernier sur le sol. / In the context of sustainable development, and to limit environmental impact, usage of fine-grained soils takes an expending place in earthworks. Sadly, the control of such materials through construction leads to difficulties during compaction, such as lamination and wave effect. As part of the French ANR project TerreDurable, this thesis aims to research compaction, mostly marls close to saturation. Observations carried out by practitioners serves as base for the experimental programme (Vinci Construction Terrassement, Valerian, Egis Géotechnique), to achieve surveys showing the main known difficulties and poor usages. After a discussion on the effect of measurement methods on nucleation in fine-grained soils, the study follows a full-scale in situ compaction test, articulated around four parameters: water content, grinding, compactor type and compaction energy. These variations lead 24 parcels sometimes out of the French legal frame (Guide des Terrassement Routiers). After realisation and visual observations, each of the parcels undergoes samplings and dynamic penetrometers to evaluate their state and hydro mechanical response. These analyses give data regarding good compaction practice, but also soil state variables after compaction. Then, proctor and CBR tests first show the effect of soil preparation on their outcomes. Afterwards, retention curves in the quasi-saturated domain are conducted from the Proctors. These measures compared to the full scale in situ compaction test, provide a frame to its results and confirm initial observations. Finally, aiming to study state variables evolution during compaction, a triaxial cell is developed. Equipped with a tensiometer at its base, flat Plexiglas windows are created enabling digital image correlation (DIC) for volume changes assessments. These windows allow for limited optical deformations and measurement facilitation. The conception and the calibration of the cell are presented to evaluate its precision. Then, the first tests to reproduce compaction, based on in-situ references, are carried out. Despite difficulties to simulate compactor passes in the cell, it provided elements of reflexion regarding the effect of compaction.

La pollution d’aquifères par des hydrocarbures est très persistante et difficile à traiter, devenant un enjeu majeur pour l’environnement en raison de l’effet négatif sur la santé humaine. La génération de mousse in situ combinée au lavage de sols est une technique de dépollution innovante, permettant un meilleur contrôle de la mobilité des fluides dans des formations hétérogènes. Le but de cette méthode est de bloquer l’écoulement dans les couches à forte perméabilité pour améliorer l’efficacité de balayage des strates peu perméables.Le mémoire se divise en deux parties principales décrivant une étude expérimentale et une étude numérique.Une sélection préalable de tensioactifs respectueux de l’environnement à été réalisée sur la base de leur moussabilité. Le sucrose laurate (émulsifiant alimentaire) a été retenu et comparé avec un tensioactif dit classique. Des tests sur colonnes 1-D ont permis d’étudier l’influence de la perméabilité, du type de tensioactif et de la qualité de la mousse sur le facteur de résistance à la mobilité du gaz. Les résultats, interprétés à l’aide de la pression capillaire, révèlent deux régimes d’écoulement, correspondants aux deux textures de mousse : « weak » et « strong ». Des expériences sur pilotes 2-D hétérogènes ont permis de visualiser les différentes phases du processus de remédiation et de comparer l’efficacité de balayage avec et sans une région bloquée par de la mousse.La partie modélisation comprend une simulation numérique des tests sur colonne 1-D en utilisant le code UTCHEM et une étude de sensibilité des paramètres les plus importants du modèle, ainsi qu’une modélisation des tests de traçage sur pilote 2-D avec le code MODFLOW. / Aquifer pollution with hydrocarbons is very persistent and difficult to treat, becoming a major issue for the environment because of the negative effect on human health. In situ foam generation combined with soil washing is an innovative remediation technology that allows a better fluid mobility control in heterogeneous formations. The purpose of this method is to block the flow through the high permeability layers in order to improve the sweep efficiency of low permeability strata.The thesis is divided into two main parts describing an experimental study and a numerical study.A preliminary selection of environmentally-friendly surfactants was carried out on the basis of their foamability. Sucrose laurate (emulsifier from food industry) was selected and compared with a conventional surfactant. 1-D column tests were performed to study the influence of permeability, surfactant type and foam quality on the resistance factor. The results, interpreted using the capillary pressure, show two flow regimes, corresponding to the two foam textures: "weak" and "strong". Experiments on 2-D heterogeneous pilot allowed visualizing the different steps of the remediation process and comparing the sweep efficiency with and without a region blocked by foam.The numerical part includes modeling 1-D column tests using UTCHEM, a sensitivity study of the most important parameters of the model, and a simulation of tracer tests on 2-D pilot using MODFLOW.

[pt] Um estudo experimental em modelos reduzidos do duto PE-3, construído na Baía de Guanabara em 2003, é descrito neste trabalho. O duto PE-3 tem diâmetro externo de 457,2 mm e a sua principal característica é a sua geometria em ziguezague. Este duto transporta óleo combustível à temperatura de 80ºC da Refinaria de Duque de Caxias aos terminais de navios na Ilha D´Água. O presente estudo foi realizado em modelos reduzidos com semelhança física, e teve como objetivo avaliar experimentalmente o comportamento do modelo variando-se o ângulo de ziguezague e o comprimento do duto. Os modelos foram submetidos à variação de temperatura, pressão interna e condições de apoio lateral e longitudinal, simulando as condições reais de trabalho do protótipo. Para cada comprimento (12, 16 e 18 metros) e ângulo de ziguezague (5º, 10º e 15º) foram realizados ensaios com o modelo sem reação lateral do solo, com reação lateral simulando 1 metro de enterramento no protótipo, com reação lateral simulando 1 metro de enterramento e vão central livre, e com imperfeição horizontal. Foram realizados ainda 2 ensaios com um duto reto para efeito de comparação com o modelo zig-zag. Os resultados mostraram que a geometria em ziguezague minimiza os esforços gerados pela expansão térmica do duto. / [en] An experimental study on reduced scale models of the PE-3 pipeline, built in Guanabara Bay in 2003, is described in this work. The main characteristic of the PE-3 pipeline is the zig-zag geometry. This pipeline has an external diameter of 18 and is used to transport heavy heated oil from the Duque de Caxias refinary to a shipping terminal. The present study was carried out in reduced models with physic similitude, and the objective is to evaluate experimentally the behavior of the model, varying the zig-zag angle and the length of the pipeline. The models were submitted to temperature variation, internal pressure and different conditions of lateral and longitudinal support, simulating the real working conditions of the prototype. For each length (12m, 16m and 18m) and zig-zag angle (5°, 10° and 15°) tests were carried out with the model without lateral reaction of the soil, with lateral reaction simulating 1 meter of buried prototype, with lateral reaction simulating 1 meter of buried prototype and central free span, and with horizontal imperfection. Two straight pipeline tests were carried out in order to compare with the zig-zag model. The results showed that the zig-zag geometry minimizes the effects caused by the thermal expansion of the pipeline.

The site of confluence of the artery and the portal vein in the liver still appears to be controversial. Anatomical studies suggested a presinusoidal or an intrasinusoidal confluence in the first, second or even final third of the sinusoids. The objective of this investigation was to study the problem with functional biochemical techniques. Rat livers were perfused through the hepatic artery and simultaneously either in the orthograde direction from the portal vein to the hepatic vein or in the retrograde direction from the hepatic vein to the portal vein. Arterial how was linearly dependent on arterial pressure between 70 cm H2O and 120 cm H2O at a constant portal or hepatovenous pressure of 18 cm H2O. An arterial pressure of 100 cm H2O was required for the maintenance of a homogeneous orthograde perfusion of the whole parenchyma and of a physiologic ratio of arterial to portal how of about 1:3. Glucagon was infused either through the artery or the portal vein and hepatic vein, respectively, to a submaximally effective ''calculated'' sinusoidal concentration after mixing of 0.1 nmol/L. During orthograde perfusions, arterial and portal glucagon caused the same increases in glucose output. Yet during retrograde perfusions, hepatovenous glucagon elicited metabolic alterations equal to those in orthograde perfusions, whereas arterial glucagon effected changes strongly reduced to between 10% and 50%. Arterially infused trypan blue was distributed homogeneously in the parenchyma during orthograde perfusions, whereas it reached clearly smaller areas of parenchyma during retrograde perfusions. Finally, arterially applied acridine orange was taken up by all periportal hepatocytes in the proximal half of the acinus during orthograde perfusions but only by a much smaller portion of periportal cells in the proximal third of the acinus during retrograde perfusions. These findings suggest that in rat liver, the hepatic artery and the portal vein mix before and within the first third of the sinusoids, rather than in the middle or even last third.

This thesis investigates the refrigerant (R-134a) flow in three minichannels having different geometries experimentally. During the last 40 years heat transfer in small scales has been a very attractive research area. Improvements in heat transfer in the refrigeration applications by means of usage of micro/minichannels provide significant developments in this area. Also it is known that experimental studies are very important to constitute a database which is beneficial for new developments and research. During the two-phase flow experiments conducted in the minichannels, low mass flow rates and constant wall temperature approach, which are the conditions in the evaporators of the refrigerator applications were applied because one of the purposes of this study is to determine the most ideal minichannel among the tested minichannels for usage in the evaporator section of the refrigerators. Two-phase flow experiments were made with refrigerant R134a in the three minichannels having hydraulic diameters of 1.69, 3.85 and 1.69 mm respectively. As distinct from the others, the third minichannel has a rough inner surface. Comparison of the experimental results of the three minichannels was made in terms of forced convection heat transfer coefficients and pressure drop at constant quality and mass flux values. As a result of the experiments, the most ideal minichannel among the tested minichannels was determined for the evaporator applications in the refrigerators.