L'objectif global visé par les travaux de cette thèse est d'améliorer la caractérisation des propriétés macroscopiques des matériaux poreux à structure rigide ou souple par des approches inverses et indirectes basées sur des mesures acoustiques faites en tube d'impédance. La précision des approches inverses et indirectes utilisées aujourd'hui est principalement limitée par la qualité des mesures acoustiques obtenues en tube d'impédance. En conséquence, cette thèse se penche sur quatre problèmes qui aideront à l'atteinte de l'objectif global précité. Le premier problème porte sur une caractérisation précise de la porosité ouverte des matériaux poreux. Cette propriété en est une de passage permettant de lier la mesure des propriétés dynamiques acoustiques d'un matériau poreux aux propriétés effectives de sa phase fluide décrite par les modèles semi-phénoménologiques. Le deuxième problème traite de l'hypothèse de symétrie des matériaux poreux selon leur épaisseur où un index et un critère sont proposés pour quantifier l'asymétrie d'un matériau. Cette hypothèse est souvent source d'imprécision des méthodes de caractérisation inverses et indirectes en tube d'impédance. Le critère d'asymétrie proposé permet ainsi de s'assurer de l'applicabilité et de la précision de ces méthodes pour un matériau donné. Le troisième problème vise à mieux comprendre le problème de transmission sonore en tube d'impédance en présentant pour la première fois un développement exact du problème par décomposition d'ondes. Ce développement permet d'établir clairement les limites des nombreuses méthodes existantes basées sur des tubes de transmission à 2, 3 ou 4 microphones. La meilleure compréhension de ce problème de transmission est importante puisque c'est par ce type de mesures que des méthodes permettent d'extraire successivement la matrice de transfert d'un matériau poreux et ses propriétés dynamiques intrinsèques comme son impédance caractéristique et son nombre d'onde complexe. Enfin, le quatrième problème porte sur le développement d'une nouvelle méthode de transmission exacte à 3 microphones applicable à des matériaux ou systèmes symétriques ou non. Dans le cas symétrique, on montre que cette approche permet une nette amélioration de la caractérisation des propriétés dynamiques intrinsèques d'un matériau.

BACKGROUND:Recent advances suggest fallopian tube as the main cellular source for women's pelvic serous carcinoma (PSC). In addition to TP53 mutations, many other genetic changes are involved in pelvic serous carcinogenesis. IMP3 is an oncofetal protein which has recently been observed to be overexpressed in benign-looking tubal epithelia. Such findings prompted us to examine the relationship between IMP3 over-expression, patient age and the likelihood of development of PSC.METHODS:Fallopian tubes from three groups (low-risk, high-risk, and PSC) of patients with matched ages were studied. Age was recorded in 10years intervals ranging from age 20 to older than 80. The number of IMP3 signatures (defined by 10 or more tubal secretory cells stained positively and continuously in benign appearing tubal mucosa) from both tubal fimbria and ampulla segments was measured. The data was analyzed by standard contingency table and Poisson distribution methods after age adjustment. IMP3 overexpression was also examined in serous tubal intraepithelial carcinoma and PSC.RESULTS:The positive IMP3-stained cells are mainly tubal secretory cells. The absolute number of tubal IMP3 signatures increased significantly within each age group. Age remained a significant risk factor for serous neoplasia after age adjustment. IMP3 signatures were more frequent in the patients of both high-risk and PSC groups. The presence of IMP3 signatures in tubal mucosa was significantly associated with tubal or pelvic serous carcinogenesis (p<0.001).CONCLUSIONS:The findings suggest that tubal secretory cells with IMP3 signatures showing growth advantage could potentially serve as a latent precancer biomarker for tubal or pelvic serous carcinomas in women.

<p>Proper morphogenesis is essential for both form and function of mammalian craniofacial and neural tube development. Craniofacial deformities and neural tube defects are highly prevalent human birth defects. Although studies concerning craniofacial and neural tube development have revealed important genetic and/or environmental factors, understanding the mechanisms underlying proper development and the defects remain incomplete. </p><p>Among many genes that were cloned as the gastrula organizer genes in 1990s, Nog, a secreted BMP antagonist, is expressed in the relevant domains during craniofacial and neural tube development. Previous studies show that Nog null embryos exhibit fully penetrant spina bifida (open spine) and to the lesser extent exencephaly (open brain). Moreover, Nog null mice display deformities in skeletal structures including defects in craniofacial skeleton. As such, Nog is essential for proper neural tube and craniofacial development. However, it is still not clear that which domain(s) of Nog are responsible for proper craniofacial development or neural tube closure. In addition, it is also an important question when, and in what capacity Nog is necessary during development of craniofacial and neural tube.</p> / Dissertation

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In this study, one and two-dimensional models are developed for the evaluation of the thermal performance of a delugeable flat tube bundle to be incorporated in the second stage of an induced draft hybrid (dry/wet) dephlegmator (HDWD) of a direct air-cooled steam condenser (ACSC). Both models are presented by a set of differential equations. The one-dimensional model is analysed analytically by using three methods of analysis which are: Poppe, Merkel, and heat and mass transfer analogy. The two-dimensional model is analysed numerically by means of heat and mass transfer analogy method of analysis whereby, the governing differential equations are discretised into algebraic equations using linear upwind differencing scheme. The two-dimensional model’s accuracy is verified through a comparison of the two dimensional solutions to one dimensional solutions. Satisfactory correlation between the one and two-dimensional results is reached. However, there is a slight discrepancy in the solutions, which is mainly due to the assumptions made in one-dimensional model. The effect of tube height, tube pitch, tube width, deluge water mass flow rate, frontal air velocity, steam, and air operating conditions on the heat transfer rate and air-side pressure drop for both wet and dry operating modes are investigated. The long tube height, large tube width, small tube pitch, and high frontal air velocity are found to increase the tube bundle’s performance. However, this performance is associated with a high airside pressure drop. The performance of the deluged flat tube bundle is found to be less sensitive to the changes in the deluge water mass flow rate and air operating conditions. Furthermore, the best configuration of a delugeable flat tube bundle is identified through a comparison to round tube bundle presented by Anderson (2014). The performance of the round tube bundle is found to be around 2 times, and 1.5 times of that of flat tube bundle, when both bundles operate as an evaporative and dry air-cooled condenser respectively. / AFRIKAANSE OPSOMMING: In hierdie studie is een en twee-dimensionele modelle ontwikkel vir die evaluering van die termiese prestasie van 'n benatbare plat buis bundel in die tweede stadium van 'n geïnduseerde ontwerp hibriede (droë / nat ) deflegmator van 'n direkte lugverkoelde stoom kondensator. Beide modelle is aangebied deur 'n stel van differensiaalvergelykings. Die een-dimensionele model is analities ontleed deur die gebruik van drie metodes van analise wat: Poppe, Merkel, en die hitte en massa-oordrag analogie. Die twee-dimensionele model is numeries ontleed deur middel van hitte en massa-oordrag analogie metode van analise waardeur , die regerende differensiaalvergelykings gediskretiseer in algebraïese vergelykings met behulp van lineêre windop differensievorming skema. Die tweedimensionele model se akkuraatheid is geverifieer deur 'n vergelyking van die twee dimensionele oplossings te een dimensionele oplossings. Bevredigende korrelasie tussen die een en twee-dimensionele resultate bereik word. Maar daar is 'n effense verskil in die oplossings, wat is hoofsaaklik te wyte aan die aannames wat gemaak in een-dimensional model. Die effek van buis hoogte, buis toonhoogte, buis breedte, vloed water massa-vloeitempo, frontale lug snelheid, stoom, en in die lug werktoestande op die hitte oordrag snelheid en lug - kant drukval vir beide nat en droë maatskappy modi word ondersoek. Die lang buis hoogte, groot buis breedte, klein buisie toonhoogte, en 'n hoë frontale lug snelheid gevind die buis bundel se prestasie te verhoog. Tog is hierdie prestasie wat verband hou met 'n hoë lug - kant drukval. Die prestasie van die oorstroom plat buis bundel gevind word minder sensitief vir die veranderinge in die vloed water massa-vloeitempo en lug werktoestande. Verder is die beste opset van 'n benatbare plat buis bundel geïdentifiseer deur 'n vergelyking met ronde buis bundel aangebied deur Anderson (2014). Die prestasie van die ronde buis bundel gevind word om 2 keer, en 1.5 keer van daardie plat buis bundel , wanneer beide bundels funksioneer as 'n damp en droë lugverkoelde kondensor onderskeidelik.

ENGLISH ABSTRACT: Current understanding of the hydraulic stability of a stacked geotextile tube structure under wave attack is limited. Failure mechanisms that lead to instability are complicated and there is, as yet, no generic approved design method. 2D physical modelling in the large wave/current flume of the Stellenbosch University was done to test various set-up and hydraulic conditions to determine the hydraulic stability of a stacked geotextile tube structure against wave attack. Sixty-five test runs of approximately 1,000 waves each were run. Modelling was done on two different scales that had good similitude, despite the fact that the same geotextile and fill material were used in both. The results provided by the physical modelling gave wave conditions larger than anticipated for hydraulic stability. It was found that the term ―failure‖ was too loosely defined in most cases and that, depending on the definition of structure failure the severity of the wave conditions at failure increased substantially. Sliding was found to be the key failure mechanism for a structure constructed from stacked, 80% sand filled, geotextile tubes. The crest tube receives the most severe loading and is the critical tube in the structure. Structures with double tube crests were found to be negligibly more stable than structures with single tube crests, but reduce energy transmission to the leeside of the structure. Impact loading of the structure combined with wave transmission over the structure explained the wave force on the crest tube of the structure. A modified Goda (1974) method incorporating a wave reduction factor for wave transmission and an angle descriptive of the crest tube position were used. The descriptive angle was derived from results obtained from the physical modelling. The use of this method provides results that correlate well with those found in the physical modelling and with results obtained in previous research. The method has the additional advantage that it is less constrained by limitations for application than those of previous studies / AFRIKAANSE OPSOMMING: Die begrip van die hidroliese stabiliteit van ‘n struktuur gebou uit gepakte geotekstielsandbuise teen golf aanval, is tans beperk. Faal meganismes wat lei tot die onstabiliteit van ‘n struktuur is ingewikkeld en daar is geen generiese aanvaarde ontwerp metode tans in gebruik nie. 2D fisiesemodellering is in die groot golfkanaal van die Universiteit Stellenbosch uitgevoer. ‘n Verskeidenheid van struktuur-uitlegte en hidroliese toestande is getoets om die hidroliese stabiliteit van die struktuur teen golf aanval te bepaal. ‘n Totaal van 65 toetse van ongeveer 1,000 golwe elk is voltooi. Modellering is op twee verskillende skale gedoen, wat goed vergelyk het ten spyte van die feit dat dieselfde geotekstiel en vul materiaal in albei gebruik is. Resultate verkry vanaf die fisiese modellering het groter as verwagte golftoestande vir hidroliese stabiliteit gegee. Dit is gevind dat die definisie van faal (mislukking) in die meeste gevalle swak beskryf is en dat, afhangende van wat as faal van die struktuur beskou word, die golftoestande aansienlik beïnvloed word. Die skuif van die buise is die hoof faal meganisme vir ‘n gepakte geotekstielbuis-struktuur met ‘n vulpersentasie van 80%. Die buis op die kruin van die struktuur word die swaarste belas en is die kritiese buis in die struktuur. Strukture met dubbel buis kruine is onbeduidend meer stabiel as dié met slegs ‘n enkele buis as kruin. Die energie wat na die lysy van die struktuur oorgedra word, is egter beduidend minder. Impak belasting van die struktuur gekombineer met golf-transmissie oor die struktuur, verduidelik die stabiliteit van die buis op die kruin van die struktuur. ‘n Gemodifiseerde Goda (1974) metode met ‘n golfverminderigs faktor word gebruik om golf-transmissie oor die struktuur te akkommodeer, saam met ‘n hoek wat beskrywend is van die posisie van die kruin buis. Die beskrywende hoek is afgelei uit resultate verkry uit die fisiesemodellering. Hierdie metode gee resultate wat goed korreleer met dié verskaf deur die fisiese modellering en die resultate van vorige navorsing oor geotekstielbuis stabiliteit. Die metode het ‗n bykomende voordeel deurdat dit minder begrens is deur beperkings m.b.t. toepassing as die van vorige studies.

Changes in the health-care system during the past decades have led to an increased transfer of health care to the home environment which also concerns patients treated with home enteral tube feeding (HETF). Research is scarce about how HETF care is functioning. Therefore, the overall aim with this thesis was to describe and explore HETF care and treatment from patients', relatives' and nurses' perspectives. Three qualitative and one quantitative study were used. The findings showed that the HETF treatment and care had a great impact on daily life for both patients and their relatives and implied many practical, emotional and social problems in their daily life, which they strived to manage. Side effects were common and the patients' reported low HRQL and general health. The amount and quality of received guidance and support from the health care, not least before discharge, turned out to have impact on the patients' and the relatives' daily life and how they could manage their situation. Lack of guidance and support meant insecurity, worries and distress. Cooperation in the care trajectory was found to be decisive for how well the care was running. Nurses' knowledge about tube feeding and discharge planning procedures, their commitment to the patients' care, as well as clarity regarding responsibility of HETF care were factors of crucial importance on how the cooperation worked, and the quality of the HETF care. This thesis shows the need of improvements regarding the care of HETF patients and their relatives.

Dans ce document sont présentées des expériences sur les instabilités de cisaillement dans l'écoulement concentrique à co-courant de deux fluides miscibles. Les deux fluides sont de même masse volumique mais le fluide à la paroi a une viscosité supérieure à celle du fluide de coeur. Deux paramètres de contrôle sont utilisés, le nombre de Reynolds et le rayon du fluide de coeur. Nous avons toujours obtenu un écoulement instable et deux motifs d'instabilités ont été observés : perles et champignons. Nous avons établi le diagramme d'existence de ces motifs dans le plan des paramètres de contrôle. Pour les motifs de la forme de champignons et pour certaines valeurs de paramètres de contrôle, les instabilités apparaissent très près de l'injection et montre une largeur de spectre fine. Ce comportement pourrait être la signature d'une transition entre des instabilités convectives et des instabilités absolues. Nous avons essayé de caractériser l'état absolu ou convectif du système par des mesures expérimentales, notamment par des expériences de forçage de la fréquence. Nous avons comparé nos résultats à des simulations numériques qui s'accordent en partie à nos résultats expérimentaux, et à une analyse de stabilité linéaire aux grandes longueurs d'onde.

The late University of Canterbury civil engineering lecturer Peter Giddens developed a range of simple microhydro turbines, with publications from as early as the 1980s. He considered that a range of simple but well-designed turbines which covered the gamut of possible small sites would be more useful than any single turbine. He started with radial inflow turbines, then set about extending their range of applicability by increasing specific speed. That extension was continued by the research in this thesis, which aimed to produce a design with a minimum efficiency of 70 % at a specific speed of at least 600 (rev/min, kW, m). Achieving those targets would differentiate it from existing microhydro designs. In order to reach those performance targets, the volute, runner, and draft tube were examined through experiment and computational fluid dynamics models to characterize past designs and test the validity of their embodied assumptions. A prototype with a design specific speed of 650 was built and fully characterized by dynamometer testing. Measurements of the outlet velocity distribution of two of Peter Giddens’s volutes confirmed that single tangential inlet volutes are not torque-free when certain geometric conditions are met; swirl increased through those volutes by 70 % or more depending on the design. A new overall turbine design was proposed, where axial flow enters the runner and swirling flows leaves it. This required the design of a novel volute. Through computational analysis, the effect of swirling flow entering the conical draft tube was shown to affect its pressure recovery: negatively for draft tubes with small angles, positively for larger angles. It was shown that the peak pressure recovery of an optimum draft tube was not likely to be improved upon by the use of swirl, and since there was uncertainty in the analysis, a conservative draft tube was specified for the prototype. A flat-bladed runner was designed for the prototype and computational modeling indicated its performance would be sensitive to small changes in flow angle. Despite that sensitivity — an intrinsic property of high specific speed runner velocity triangles — the computational model was shown to give good predictions of the runner flow characteristics, although not its effciency. Finally, a 1.2 kW prototype was built and achieved a peak net effciency of 64 % as defined by the American Society of Mechanical Engineers at a net head of 2.07 m, a flowrate of 94 L/s, and a runner shaft speed of 1670 rev/min, corresponding to a specific speed of 740. Maximum measured runner efficiency of 87 % also occurred at those conditions. Compared to existing designs, that performance extended the operational envelope of microhydro turbines considerably. A three-zone computational model of the entire prototype was assembled and trialled, but not validated. It is concluded that for efficient high specific speed turbines, volute swirl characteristics must be known with confidence, as the volute sets the conditions at the leading edge for peak runner efficiency. A simple but efficient runner may be made using flat blades, showing the potential for this geometry even when made by limited workshops. Adding a free-vortex tangential velocity distribution to the inlet flow of a stalled conical draft tube may increase its pressure recovery, although it is not likely to exceed the best performance obtainable with axial inlet flow. Therefore taking measures to reduce the peak fluid velocity entering the draft tube could be more beneficial to overall performance than seeking outright improvements in draft tube pressure recovery.

Cette thèse porte sur le rayonnement X bêtatron généré par des électrons accélérés par sillage laser plasma dans des tubes capillaires diélectriques. En l'état actuel de la technologie des impulsions laser multi-térawatts, on peut produire des faisceaux ayant une intensité crête élevée, de l'ordre de 1018 W/cm2 dans le plan focal. Une telle impulsion laser se propageant au sein d'un gaz sous-dense conduit à des phénomènes d'interaction laser-plasma non-linéaires, tels que la création d'une bulle de plasma, i.e. une bulle ne contenant aucun électron, suivant le laser. La séparation spatiale des charges en résultant crée des champs électriques très élevés au sein de la bulle, de l'ordre de 100 GV/m, ce qui offre la possibilité d'accélérer des électrons jusqu'au GeV après seulement quelques centimètres d'interaction. En outre, un rayonnement synchrotron ultra-bref, appelé rayonnement bêtatron, est produit lors de l'accélération des électrons puisque ces derniers, soumis au champ électrique radial de la bulle plasma, ont une trajectoire oscillante. Cette thèse présente des résultats expérimentaux sur la génération et l'optimisation de faisceaux d'électrons et de leur rayonnement X, en particulier lorsque le tube capillaire est utilisé pour recueillir l'énergie du halo laser dans le plan focal facilitant l'autofocalisation du laser sur de longues distances. Des faisceaux d'électrons de quelques dizaines de picocoulomb, avec une énergie maximale allant jusqu'à 300 MeV, et dont le spectre est soit piqué à haute énergie soit exponentiellement décroissant, ont été produits dans des tubes capillaires de 10 mm de long avec l'installation laser du Lund Laser Center (LLC, en Suède) par une impulsion laser de 40 fs d'un 16 TW Ti: Saphir. Un rayonnement bêtatron a également été mesuré, il se compose de de photons X dont l'énergie est comprise entre 1 et 10 keV et atteint une luminosité maximale d'environ 1021 photons/s/mm²/mrad²/0.1%BW. Cela équivaut à environ 30 fois l'intensité des faisceaux générés dans le cas des jets de gaz de longueur 2 mm ne disposant pas de guidage optique externe. La compensation des fluctuations de pointé laser permet de minimiser les fluctuations des propriétés du faisceau d'électrons. On obtient des faisceaux d'électrons dont les fluctuations tir-a-tir sont de 1 mrad en pointé, de quelques pourcents en énergie et d'environ 20% RMS en charge. La fluctuation en charge du faisceau, qui peut être considérée comme relativement grande, s'avère être principalement corrélée à la fluctuation en puissance du laser. De plus, il a été montré que le rayonnement bêtatron pouvait être utilisé pour caractériser le processus d'accélération des électrons en caractérisant le nombre moyen d'oscillations bêtatron effectuées par les électrons à l'intérieur de la bulle plasma. La taille typique des sources de rayonnement X (dimension pour laquelle l'intensité gaussienne est égale à 1/e² de la valeur crête) est estimée à ~ 2.5 µm en utilisant un modèle de diffraction de Fresnel induite par une lame de rasoir. Cela correspond à une émittance RMS normalisée pour le faisceau d'électrons d'environ 0,83π mm.mrad. Des simulations tridimensionnelles particle-in-cell (PIC) ont été effectuées et confirment les résultats expérimentaux. Elles indiquent également que les paquets d'électrons générés ainsi que les flashs X directionnels sont ultra-brefs : ~ 10 fs.

The purpose of this research project is the design and optimization of complex chemical engineering problems, by employing evolutionary algorithms (EAs). EAs are optimization techniques which mimic the principles of genetics and natural selection. Given their population-based approach, EAs are well suited for solving multiobjective optimization problems (MOOPs) to determine Pareto-optimal solutions. The Pareto front refers to the set of non-dominated solutions which highlight trade-offs among the different objectives. A broad range of applications have been studied, all of which are drawn from the chemical engineering field. The design of an industrial packed bed styrene reactor is initially studied with the goal of maximizing the productivity, yield and selectivity of styrene. The dual population evolutionary algorithm (DPEA) was used to circumscribe the Pareto domain of two and three objective optimization case studies for three different configurations of the reactor: adiabatic, steam-injected and isothermal. The Pareto domains were then ranked using the net flow method (NFM), a ranking algorithm that incorporates the knowledge and preferences of an expert into the optimization routine. Next, a multiobjective optimization of the heat transfer area and pumping power of a shell-and-tube heat exchanger is considered to provide the designer with multiple Pareto-optimal solutions which capture the trade-off between the two objectives. The optimization was performed using the fast and elitist non-dominated sorting genetic algorithm (NSGA-II) on two case studies from the open literature. The algorithm was also used to determine the impact of using discrete standard values of the tube length, diameter and thickness rather than using continuous values to obtain the optimal heat transfer area and pumping power. In addition, a new hybrid algorithm called the FP-NSGA-II, is developed in this thesis by combining a front prediction algorithm with the fast and elitist non-dominated sorting genetic algorithm-II (NSGA-II). Due to the significant computational time of evaluating objective functions in real life engineering problems, the aim of this hybrid approach is to better approximate the Pareto front of difficult constrained and unconstrained problems while keeping the computational cost similar to NSGA-II. The new algorithm is tested on benchmark problems from the literature and on a heat exchanger network problem.