A Tomografia de Impedância Elétrica (TIE) é um método de imagem que permite estudarmos alterações regionais de ventilação pulmonar com alta resolução temporal. Estudamos a influência da posição corporal e do esforço expiratório no esvaziamento regional pulmonar comparando dados de espirometria com os da TIE adquiridos simultaneamente. MÉTODOS: Oito voluntários monitorados continuamente com TIE, realizaram manobras de capacidade vital lenta (CVL) com washout de nitrogênio (WN2) e capacidade vital forçada (CVF) nas posições sentado, decúbito lateral direito (DLD) e esquerdo (DLE). Em todas as posições, comparamos a variação global de impedância (Z) com os volumes da espirometria. Analisamos também as variações regionais de volume do pulmão direito e esquerdo, em cada posição, e a cada 10% da expiração total através da TIE; estes dados foram comparados com análise do WN2. RESULTADOS: Na espirometria e na TIE, houve uma redução no volume total expirado na CVF e na CVL dos decúbitos laterais quando comparados à posição sentada (P = 0,001). Na análise da CVL através da TIE, observamos um fluxo maior no pulmão dependente (de 2 a 10 vezes maior), em ambos os decúbitos laterais, com inversão deste padrão aproximadamente na metade da capacidade vital. Já na CVF o Z foi semelhante entre os pulmões ao longo da expiração, independente do decúbito, semelhante à situação isogravitacional (i.e., sentado) (p<0,001). O traçado de WN2 mostrou uma inclinação precoce (fase IIIb) ocorrendo apenas nos decúbitos laterais, além da fase IV ao final. A ascensão lenta da fase IIIb esteve sempre associada a uma significativa mudança no padrão de esvaziamento observado à TIE, onde o esvaziamento preferencial do pulmão dependente dava lugar a um esvaziamento preferencial do pulmão não-dependente. CONCLUSÃO: Em indivíduos sadios e nas situações de baixo esforço expiratório (CVL), a gravidade exerce forte influência na distribuição e variação dos volumes pulmonares ao longo da expiração, sugerindo um significante gradiente vertical de pressões pleurais. O esforço expiratório máximo atenua esta influência da gravidade, sugerindo que outros fatores passam a determinar o fluxo expiratório. / Electrical Impedance Tomography, (EIT) is an imaging method that allows studying changes in regional pulmonary ventilation with high temporal resolution. We studied the influence of body position and expiratory effort on regional lung emptying comparing data from spirometry with the EIT acquired simultaneously. METHOD: Eight volunteers monitored continuously with EIT, performed slow vital capacity (SVC) with single-breath nitrogen washout (SBNW) and forced vital capacity (FVC) maneuvers in sitting position, right (RLD) and left lateral decubitus (LLD). In all three positions we compared the impedance change (Z) with spirometry absolute volumes and analyzed the regional volume variation of right and left lungs in each position and every 10% step of total expiration with EIT; this data was compared with SBNW analysis. RESULTS: In spirometry and EIT, there was a reduction in the total volume expired in FVC and SVC in lateral recumbency when compared to the sitting position (P = 0,001). In the analysis of the SVC with EIT we noticed a greater flow in the dependent lungs (from 2 to 10 times higher) on both lateral decubitus, with reversal of this pattern in approximately half of the expired vital capacity. On FVC the Z was similar between the lungs during the entire expiration, regardless of decubitus, and similar to the situation isogravitacional (ie, sitting) (p<0,001). The SBNW curves showed an early inclination (phase IIIb) occurring only in the lateral decubitus, besides the final rise of phase IV. The slow rise of phase IIIb was always associated with a significant change in the emptying pattern observed with the EIT, when the preferential emptying of the dependent lung gave place to preferential emptying in the non-dependent lung. CONCLUSION: In healthy subjects and in situations of low effort (SVC), gravity exerts strong influence on the distribution and variation of lung volume during the expiration, suggesting a significant vertical gradient of pleural pressure. The maximum expiratory effort mitigates this gravitational influence, suggesting that other factors may determine the expiratory flow

Orientador: João Poterio Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-03T22:54:05Z (GMT). No. of bitstreams: 1 Silveira_SandraAparecidaFerreira_D.pdf: 6523411 bytes, checksum: 992a09f837ade47ed8e335f39e9f2de6 (MD5) Previous issue date: 2004 / Resumo: A insuficiência venosa crônica (IVC) dos membros inferiores acarreta, com o passar do tempo, o aumento do volume de sangue venoso na perna. Esse volume venoso está diretamente relacionado com a duração e a gravidade da insuficiência venosa, bem como com a capacidade da bomba venosa da panturrilha em expulsá-lo desse compartimento. A medida do volume venoso da perna é tradicionalmente efetuada com pneumopletismógrafo; a nossa proposta de medir o volume venoso com a ultra-sonografia duplex (US-duplex) baseia-se no fato de que este é um novo método onde se pode medir o fluxo em veias isoladas e complementar o exame das pernas com varizes. O volume venoso contido no reservatório da panturrilha foi considerado como sendo a soma dos volumes de sangue que são expulsos pelas veias safena magna e poplítea na altura da prega do joelho durante a compressão externa das pernas; estas veias são as duas principais vias de saída desse compartimento. Os nossos objetivos foram determinar com a US-duplex o volume venoso nas pernas de indivíduos sem doença venosa e com varizes, e criar um índice venoso de normalidade nas pernas. Foi realizado um estudo clínico, prospectivo e randomizado em dois grupos: no Grupo 1 ¿ sem doença venosa ¿ foram incluídos 17 indivíduos, tendo sido estudadas 27 pernas, e, no Grupo 2 ¿ com varizes ¿, foram incluídos 21 pacientes tendo sido estudadas 28 pernas. A distribuição dos pacientes do Grupo 2, segundo a classificação clínica CEAP, foi a seguinte: 12 - C2, 7 ¿ C3, 2 ¿ C4, 4 - C5 e 3 ¿ C6. Medidas do fluxo volumétrico ascendente pelas veias safena magna e poplítea na altura da prega do joelho foram realizadas com aparelhos de ultra-sonografia ATL Ultramark-9 e Aloka SSD-2000, durante a compressão da perna com um manguito pneumático de 16cm por 23 cm, com pressão fixa de 150mmHg e um tempo suficiente para o desaparecimento do fluxo. Medidas dos perímetros foram realizadas em três níveis da perna e calculado o volume da panturrilha, que foi considerado igual ao produto do perímetro médio ao quadrado multiplicado por um fator de correção (16/4p), que leva em conta a largura do manguito (16cm). O índice venoso foi obtido dividindo-se o volume da panturrilha de cada indivíduo pelo volume venoso correspondente. Para determinar se existiam diferenças estatísticas entre indivíduos sem varizes (Grupo 1) e pacientes com varizes (Grupo 2) para cada uma das variáveis, foi utilizado o teste não paramétrico de Wilcoxon. Para as variáveis volume venoso (VV), volume na veia safena magna (VSAF), volume na veia poplítea (VPOP) e índice venoso (IV), existem diferenças estatísticas entre as médias dos Grupos 1 e 2. Analisando os intervalos de confiança para a mediana, existe uma linha de corte, próxima ao valor 30 para o índice venoso, que separa o Grupo 1 do Grupo 2. Foi aplicado o índice de correlação de Spearman entre a classificação clínica CEAP e o valor do índice venoso, que demonstrou não haver correlação entre essas variáveis / Abstract: Chronic venous insufficiency of the lower limbs leads to a gradual increase in the volume of venous blood in the limb. This volume is directly related to the duration and severity of the venous insufficiency, and to the ability of the calf muscle to remove blood from this compartment. The venous volume of the leg is traditionally measured by pneumoplethysmography. In this study, we used duplex ultrasonography (US) to measure the venous volume of the legs of individuals without venous disease and patient with varices, and create a venous index of normality in the legs. The choice of US to determine the venous volume was based on the fact that this method can measure blood flow in isolated veins and can complement US studies of varicose veins. The venous volume of the calf muscle was considered to be the sum of the volume of blood ejected by the saphenous and popliteal veins at the level of the knee joint during external compression of the legs. These veins are the two main exit routes for blood from this compartment. The study included two groups: group 1 consisted of 17 subjects with no venous disease (27 limbs were examined), and group 2 was composed of 21 patients with varices (28 limbs were examined). The clinical classification of the group 2 patients based on the CEAP criteria was: C2 ¿ 12, C3 ¿ 7, C4 ¿ 2, C5 ¿ 4 and C6 ¿ 3 patients. The volume of ascending blood flowing through the saphenous and popliteal veins at the level of the knee joint was measured using ATL Ultramark-9 and Aloka SSD-2000 ultrasonographs during compression of the leg with a pneumatic cuff at a fixed pressure of 150mm/Hg. The circumference of the leg was measured at three levels and the volume of the calf muscle was calculated as the mean circumference² multiplied by correction index factor (16/4p), that regards the width of cuff (16 cm). The venous index was obtained by dividing the volume of the calf muscle of each subject by the corresponding venous volume. The statistical significance of the differences between groups 1 and 2 was assessed using the non-parametric Wilcoxon test. Significant differences between the two groups were observed in the volumes of the venous (VV), saphenous (SAFV), popliteal (POPV) veins and in the venous index (VI). Analysis of the confidence intervals of the median values suggested that a venous index cut-off value close to 30 effectively separated the two groups. There was no significant correlation between the clinical classification based on the CEAP criteria and the venous index / Doutorado / Medicina Interna / Ciencias Medicas

Dans cette thèse, on s’intéresse à quelques aspects spécifiques des matériaux composites aléatoires : la taille minimale du volume élémentaire représentatif et la détermination des propriétés effectives de transport. L’objectif principal est de proposer une méthode numérique efficace permettant une détermination rapide des propriétés effectives. Les propriétés de type transport sont considérées. Il est montré que cette classe de propriétés peuvent être déterminées soit en réalisant des calculs sur un échantillon de grande taille soit en faisant moyenne sur un nombre suffisant de petites réalisations de microstructures. Cependant, pour un type de microstructure donné, la taille des ces petites réalisations ne peut pas être inférieure à une certaine limite minimale. Celle-ci est fortement influencées par plusieurs facteurs tel que type de microstructure, fractions volumiques des constituants, contrastes de propriétés entre phases, nombre de réalisation et précision acquise. Par ailleurs, deux types de représentativités sont étudiées : représentativité géométrique et celle en rapport avec les propriétés de transport. Par conséquent, deux critères distincts de taille minimale sont proposés en se basant sur des propriétés des fonctions de corrélation à deux-points. Comparant à d’autres méthodes proposées dans de large littératures, le critère proposé ici comporte un avantage car il tient compte de la morphologie de microstructure. En conséquence, des calculs numériques comme ceux par les éléments finis ne sont pas nécessaires pour la détermination de la taille minimale de REV. La validation de la méthodologie proposée est effectuée sur plusieurs exemples de microstructures 2D. / The thesis focuses on random composites and some specific features such as: the minimum size of a representative volume element (RVE) and the determination of effective transport properties. The main objective is to formulate a computationally efficient method which would allow for quick determination of effective properties. The effective properties of transport are considered. It is shown that this class of properties can be estimated either by performing calculations over one large sample or by averaging over a sufficient number of smaller microstructure realizations. However, for a given type of microstructure; the size of such smaller realizations can not be smaller than some critical minimum size. It is shown that this critical size of RVE is strongly affected by several parameters. These are: microstructure type, volume fractions of constituents, contrast in mechanical properties of composite phases, number of performed realizations as well as a desired accuracy. Furthermore, two separate types of representativity are introduced: geometrical representativity and representativity with respect to overall transport properties. Therefore, two distinct criteria for the minimum size of RVE are formulated based on the properties of the two-point correlation function. Comparing to other methods proposed in wide literature, the criterion formulated in the thesis gives an advantage: the condition proposed includes microstructure morphology. Therefore, in order to determine the minimum size of RVE none numerical calculations like those of FE are necessary. A validation of proposed methodology is performed on several examples of 2D microstructures.

L’objectif de ce travail est la caractérisation expérimentale et la modélisation du comportement mécanique des mélanges de polymères immiscibles à base de PC et de PP. Une microstructure majoritairement sphérique dans la plupart des mélanges PC/PP révèle une faible adhésion. Ceci se traduit par une déviation négative des propriétés mécaniques par rapport au % de PP ajouté. La solution de ce problème consiste à ajouter un troisième composant qui peut favoriser l’adhésion à l’interface. La présence de PP-g-MA, malgré sa faible rigidité et sa fragilité, a permis d’améliorer les propriétés mécaniques du mélange. Une approche multi-échelle est développée pour modéliser le comportement effectif du mélange PC/PP en utilisant deux types de modèles différents. Le premier est basé sur l’homogénéisation analytique et le deuxième est défini dans le cadre de l’homogénéisation numérique. La loi statistique de la répartition spatiale de la phase minoritaire a été déterminée à partir des images MEB. Cette loi a permis de générer un volume élémentaire représentatif (VER). Le comportement des constituants a été défini comme élasto-plastique. L’hypothèse d’une interface parfaite ne permet pas de rendre compte du comportement mécanique des mélanges de manière satisfaisante. Afin d’y remédier, un modèle d’endommagement interfacial a été introduit par des surfaces cohésives avec une loi de traction-séparation. Le modèle est en bon accord avec les résultats expérimentaux. Finalement, une étude paramétrique a été réalisée pour mettre en évidence les effets de la forme, du nombre et de l’orientation des nodules de la phase minoritaire sur les propriétés mécaniques non linéaires du mélange. / The objective of this work is to perform experimental characterization and to model the mechanical behaviour of immiscible PC/PP blends. A predominantly spherical microstructure, in the most PC / PP blends, reveals low adhesion due to high interfacial tension between two phases which was observed under a scanning electron microscope (SEM). This results in a negative deviation of the mechanical tensile properties accordingly to the % of PP. One of the possible solutions is to add a third component that can improve adhesion between two phases. In this work PP-g-MA was chosen. Despite its low rigidity and brittleness, it has partially improved the mechanical properties of the blends. A multi-scale approach was applied to model the homogenised behaviour of the PC / PP blends using two different types of models. The first one is based on analytical homogenization and the second one will be defined in the context of numerical homogenization. The statistical distribution law for the size of the dispersed phase was determined from the SEM images. This law was applied for representative volume element (RVE) generation. The behaviour of the constituents has been defined as elastoplastic. Initially assumed hypothesis of a perfect interface did not describe the mechanical behaviour of the blends in a satisfactory manner. In order to improve this, a model introducing cohesive surfaces to simulate interfacial damage is developed using traction-separation law. The model is in good agreement with the experimental results. Finally, parametric study was carried out to highlight the effect of the shape, the number and the orientation of dispersed phase on the nonlinear response of blends.

Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-07-18T03:37:36Z (GMT). No. of bitstreams: 1 Pinotti_JoseAristodemo_D.pdf: 940592 bytes, checksum: 52b724e9adced7085d4daf6e2d6cf515 (MD5) Previous issue date: 1968 / Resumo: Não apresentado / Abstract: Not informed / Doutorado / Doutor em Medicina

An investigation into anthropocentric, socio-economic, racial and environmental factors influencing lung function. In modern clinical practice the data derived from pulmonary function tests are an integral part of the evaluation of pulmonary disease states. Such data may shed light on the nature of the disease state, the extent (severity) of the disease and the degree of functional impairment that is present. It is generally recognized that there is a lack of consistent data regarding "normal" values in pulmonary function. Despite great progress in standardizing instrumentation, methodology and calculation of the lung function test, the interpretation of the test is complicated by the lack of standardized prediction values. The identification of race as a confounding variable is particularly important in an evaluation of appropriateness of currently used pulmonary function reference values. It has been pointed out that reference values for blacks, in particular, have deficiencies and that this issue demands urgent investigation. The study of differences in lung function in different race groups is complex. Race, itself, is a controversial concept and its close relationship to social stratification needs to be explored before differences may be attributed to race itself.

Crown volume is defined as the geometric space occupied by the crown. Crown volume and the change (growth) of crown volume over time can be an important part of multi-temporal forest analyses but is expensive and time consuming to obtain through conventional forest survey methods for large, remote areas. LiDAR-derived crown volume growth was compared to an expected amount of crown volume growth for 220 Douglasir trees in the Panther Creek, Oregon watershed. A paired t-test between expected crown volume growth and the LiDAR-derived crown volume growth resulted in a p-value of 0.85. Regression procedures between expected crown volume and LiDAR-derived crown volume in 2008 and 2012 resulted in R2 values of 0.45 and 0.53, respectively. LiDAR measured change in crown volume over time was not significantly different than the expected amount of change. With further research, multi-temporal LiDAR could become a viable tool for forest analyses.

No description available.

Numerical simulations utilizing the code SURFER++ with the incorporation of an insoluble surfactant in the VOF scheme were conducted to characterize the effects of surfactant on a drop in shear flow. The drop is suspended in a matrix liquid. A parameter called reduction, which specifically relates to a percentage decrease in effective surface tension, is used to measure the surfactant amount on the interface. In a model system where reduction = 0.1, viscosity ratio = 1 and density ratio = 1, it was found that stable drops tend to be more elongated and less inclined to the primary flow direction than drops unexposed to surfactant. This can be explained by the location of surfactant at the interface as the drop evolves. Breaking drops also show a flattened angle, but exhibit shorter necks and faster time to break than similar drops without surfactant. As reduction increases, various physical characteristics of the drops change across Reynolds number. / Ph. D.

<p> A method of modelling the mixing phenomenon in natural streams is presented. A wide range of mixing situations can be characterized using a lumped parameter model consisting of a network of ideally mixed components. The components represent two ideal states of mixing: complete mixing of the total component volume, and the other extreme where no mixing occurs in the direction of flow through the component volume. The use of frequency response techniques to match the mathematical model to the real situation is also discussed.</p> <p> Experimental work was carried out on a small natural stream to illustrate how the method is to be applied. The frequency response was obtained using sinusoidal, pulse, and impulse inputs and fluorometric dye tracing techniques. The non-linear model parameters were evaluated using the principles of least squares. The mathematical model chosen for this particular stream illustrates how the phenomenon of stagnant or slow moving regions can be included. The necessary data was collected on several days under different flow conditions to show how the model can be made a function of stream flow.</p> / Thesis / Master of Engineering (MEngr)