Fluid mixing is a challenging problem in laminar flow systems. Chaotic advection can play an important role in enhancing mixing in such flow. In this thesis, different approaches are used to enhance fluid mixing in two laminar flow systems. In the first system, chaos is generated in a flow between two closely spaced parallel circular plates by pulsed operation of fluid extraction and reinjection through singularities in the domain. A singularity through which fluid is injected (or extracted) is called a source (or a sink). In a bounded domain, one source and one sink with equal strength operate together as a source-sink pair to conserve the fluid volume. Fluid flow between two closely spaced parallel plates is modeled as Hele-Shaw flow with the depth averaged velocity proportional to the gradient of the pressure. So, with the depth-averaged velocity, the flow between the parallel plates can effectively be modeled as two-dimensional potential flow. This thesis discusses pulsed source-sink systems with two source-sink pairs operating alternately to generate zig-zag trajectories of fluid particles in the domain. For reinjection purpose, fluid extracted through a sink-type singularity can either be relocated to a source-type one, or the same sink-type singularity can be activated as a source to reinject it without relocation. Relocation of fluid can be accomplished using either "first out first in" or "last out first in" scheme. Both relocation methods add delay to the pulse time of the system. This thesis analyzes mixing in pulsed source-sink systems both with and without fluid relocation. It is shown that a pulsed source-sink system with "first out first in" scheme generates comparatively complex fluid flow than pulsed source-sink systems with "last out first in" scheme. It is also shown that a pulsed source-sink system without fluid relocation can generate complex fluid flow. In the second system, mixing and transport is analyzed in a two-dimensional Stokes flow system. Appropriate periodic motions of three rods or periodic points in a two-dimensional flow are determined using the Thurston-Nielsen Classification Theorem (TNCT), which also predicts a lower bound on the complexity generated in the fluid flow. This thesis extends the TNCT -based framework by demonstrating that, in a perturbed system with no lower order fixed points, almost invariant sets are natural objects on which to apply the TNCT. In addition, a method is presented to compute line stretching by tracking appropriate motion of finite size rods. This method accounts for the effect of the rod size in computing the complexity generated in the fluid flow. The last section verifies the existence of almost invariant sets in a two-dimensional flow at finite Reynolds number. The almost invariant set structures move with appropriate periodic motion validating the application of the TNCT to predict a lower bound on the complexity generated in the fluid flow. / Ph. D.

[EN] Crystalline silicon solar cell performance and durability is highly influenced by substrate structure and composition. In this sense, the presence of impurities and lattice imperfections degrades the electrical behavior of the substrates limiting the power conversion efficiency potential of photovoltaic devices. The influence of material electrical behavior on device performance, is further increased in next generation silicon solar cells demanding high quality substrates to reach high efficiency. A industrial-like Czochralski (Cz) p-type, ingot was grown and sawed in wafers with resistivity ranging from 0.7 Ohm.cm to 2.1 Ohm.cm and thicknesses of 200 µm. The characterization of the radial and longitudinal distribution of resistivity as well as carbon, oxygen and iron content lead to a broad characterization ot the impurity distribution at the ingot level. The low carbon content ([C]<5E15 cm-3) contrasts with remarkable high interstitial oxygen (Oi). On the other hand, while effective carrier lifetime is not significativelly affected by the high Oi content, low Fei concentrations in the ingot tail ([Fei]>1E11 cm-3) and surface ([Fei]>1E12 cm-3) led to significant lifetime degradation. In addition, lifetime mapping of the tail of the ingot showed high density of crystal dislocations. The influence of the boron and phosphorus diffusion on the electrical performance of silicon substrates was studied. Phosphorus diffusion from a POCl3 source showed a beneficial effect on lifetime that was associated with the reduction of Fei content (external gettering effect). On the other hand, boron diffusion from a BCl3 source revealed a detrimental effect that could be related to a substantial increase of [Fei] in the range of one order of magnitude. A process sequence including consecutive boron and phosphorus diffusions showed a substantial degradation of lifetime at the ingot top that could be explained by Oi precipitation rings. The influence of the crystal defects, found at the ingot tail, on lifetime degradation after the diffusion processes was also confirmed. Al-BSF cells were manufactured from a batch of wafers extracted along the ingot with efficiencies ranging between 17.8% and 18.2% and showing low dependence of solar cell performance on the solidified fraction of the ingot. Internal Quantum Efficiency (IQE) and minority carrier diffusion length (Ld) mappings further confirmed the external gettering effect developed by the phosphorus diffusion. In a further stage, Passivated Emiteer Rear Totally-diffused (PERT) cells were manufactured with efficiencies in the range of 18.8% and 19.6%. As opposed to Al-BSF cells, electrical parameters of PERT cells were influenced by solidified fraction with a reduction of cell performance near the top and tail of the ingot. In a later stage, an additional batch of solar cells of three different architectures, including Al-BSF, PERT and Passivated Emitter Rear Contact (PERC), was successfully manufactured from the same region of a Cz boron-doped ingot. Real time monitoring of the Voc enabled the study of the influence of the cell architecture on the Light Induced Degradation (LID) and Regeneration (LIR) kinetics and amplitudes. Strong correlation between the cell architectures and the degradation amplitude were observed with higher efficiency losses for PERC cells mainly due to a higher sensibility to bulk carrier lifetime degradation. In addition, the potential of LIR processes to permanently suppress the LID effects on the studied solar cell architectures was confirmed. Main causes driving the influence of the architecture in LID amplitude and LIR kinetics were further investigated. / [ES] Las características de los substratos sobre los que son fabricadas las células fotovoltaicas cristalinas constituyen un elemento fundamental en su comportamiento y durabilidad. En este sentido, la presencia de impurezas e imperfecciones en la red cristalina reduce el comportamiento eléctrico de los substratos limitando el potencial de generación eléctrica de las células. Esta limitación se acrecienta en las células de nueva generación, en las que su potencial para aumentar la eficiencia de conversión fotovoltaica solo puede hacerse efectivo al utilizar substratos con altas prestaciones eléctricas. En la presente investigación se ha procedido a la cristalización mediante la técnica Czochralski (Cz) de un lingote monocristalino, tipo p con resistividad en el rango de 0.7-2.1 Ohm.cm y tamaño industrial. Su posterior corte en obleas de 200 µm de espesor nominal ha permitido disponer de obleas distribuidas a lo largo del lingote en una fracción solidificada entre el 2.0% y el 99.4%. La caracterización del lingote ha incluido la medida de la resistividad así como la reconstrucción longitudinal y radial de su concentración en carbono, oxígeno y hierro. El reducido contenido en carbono obtenido ([C]<5E15 cm-3) contrasta con una elevada concentración en oxígeno intersticial (Oi) sin efectos apreciables en las propiedades eléctricas del lingote. Contrariamente, la reducción del tiempo de vida efectivo en la periferia y cola del lingote, es atribuido al aumento de la concentración en hierro intersticial [Fei] en dichas regiones. El estudio de la influencia de las difusiones en la evolución de las propiedades eléctricas del material incluyó difusiones de boro y fósforo mediante BCl3 y POCl3. El estudio ha constatado el efecto benéfico de la difusión de fósforo en la periferia del lingote asociado a la reducción del contenido en Fei. Por el contrario, se ha constatado el efecto perjudicial de la difusión de boro explicado en buena medida por un aumento superior a un orden de magnitud en [Fei]. La aplicación sucesiva de difusiones de boro y fósforo ha revelado una degradación apreciable en la cabeza del lingote tras la aparición de patrones circulares en la medida del tiempo de vida característicos de la precipitación de Oi. Se ha podido constatar la influencia de la elevada densidad de dislocaciones, observada en la cola del lingote, en la respuesta del substrato ante las difusiones. La fabricación de células de tecnología Al-BSF, con eficiencias comprendidas entre 17.8% y 18.2%, ha evidenciado una reducida influencia de las variaciones de las propiedades eléctricas del substrato en el comportamiento de las células finales. A su vez, la cartografía de la eficiencia quántica interna (IQE) y de la longitud de difusión (Ld) ha confirmado el efecto benéfico de la difusión de boro en la periferia y cola del lingote. La fabricación de células Passivated Emiteer Rear Totally-difused (PERT), ha permitido la obtención de dispositivos con eficiencias entre 18.8% y 19.6%. Las eficiencias muestran valores máximos en el centro del lingote y una reducción apreciable en la cabeza y cola.En una última etapa, se ha procedido a la fabricación de arquitecturas de células fotovoltaicas Al-BSF, PERT y Passivated Emitter Rear Contact (PERC), con el objetivo de estudiar los procesos de degradación y regeneración asociados a la formación de pares boro-oxígeno (B-O). El estudio de la evolución de Voc con el tiempo ha constatado una dependencia de la amplitud de degradación y cinética de regeneración con la arquitectura de célula. En este sentido se ha observado una degradación significativamente superior en las células PERC principalmente atribuible a una mayor sensibilidad a degradaciones de la calidad del substrato. A su vez se ha confirmado el potencial de los procesos de regeneración inducidos por la luz para suprimir de manera permanente los efectos de la degradación inducida por la for / [CA] Les característiques dels substrats sobre els quals són fabricades les cèl·lules fotovoltaiques cristal·lines constitueixen un element fonamental en el seu comportament i durabilitat. En aquest sentit, la presència d'impureses i imperfeccions en la xarxa cristal·lina redueix el comportament elèctric dels substrats limitant el potencial de generació elèctrica de les cèl·lules. Aquesta limitació es veu augmentada en les cèl·lules de nova generació, en què el seu potencial per augmentar l'eficiència de conversió fotovoltaica només pot fer-se efectiu mitjançant la utilització de substrats amb altes prestacions elèctriques. En la present investigació s'ha procedit a la cristal·lització mitjançant la tècnica Czochralski (Cz) d'un lingot monocristal·lí, tipus p amb resistivitat en l'interval de 0.7-2.1 Ohm.cm i mida industrial. El seu posterior tall en oblees de 200 micres de gruix nominal ha permès disposar d'oblees distribuïdes al llarg del lingot en una fracció solidificada entre el 2.0% i el 99.4%. La caracterització exhaustiva del lingot ha inclòs la mesura de la resistivitat així com la reconstrucció longitudinal i radial de la concentració en carboni, oxigen i ferro. El reduït contingut en carboni obtingut ([C]<5E15 cm-3) contrasta amb una elevada concentració d'oxigen intersticial (Oi) sense efectes apreciables en les propietats elèctriques del lingot. Contràriament, la reducció del temps de vida efectiu dels portadors de càrrega a la perifèria i cua del lingot, és atribuïda a l'augment de la concentració en ferro intersticial [Fei] en aquestes regions. L'estudi de la influència de les difusions en l'evolució de les propietats elèctriques del material va incloure difusions de bor i fòsfor mitjançant BCl3 i POCl3. L'estudi ha constatat l'efecte benèfic de la difusió de fòsfor en la perifèria del lingot associat a la reducció del contingut en Fei. Per contra, s'ha constatat l'efecte perjudicial de la difusió de bor explicat en bona mesura per un augment superior a un ordre de magnitud en [Fei]. L'aplicació successiva de difusions de bor i fòsfor ha revelat una degradació apreciable en el cap del lingot després de l'aparició de patrons circulars en la mesura del temps de vida efectiu característics de la precipitació d'Oi. Igualment s'ha pogut constatar la influència d'una elevada densitat de dislocacions, observada a la cua del lingot, en la resposta del substrat davant les difusions. La fabricació de cèl·lules de tecnologia A-BSF, amb eficiències compreses entre 17.8% i 18.2%, va permetre evidenciar una reduïda influència de les variacions de les propietats elèctriques del substrat en el comportament de les cèl·lules finals. Al mateix temps, la cartografia de l'eficiència quàntica interna (IQE) i de la longitud de difusió (Ld) ha confirmat l'efecte benèfic de la difusió de bor en la perifèria i cua del lingot. La fabricació de cèl·lules Passivated Emiteer Rear Totally-difused (PERT), ha permès l'obtenció de dispositius amb eficiències entre 18.8% i 19.6%. Les eficiències mostren valors màxims al centre del lingot i una reducció apreciable en el cap i cua. En una última etapa, s'ha procedit a la fabricació d'arquitectures de cèl·lules fotovoltaiques Al-BSF, PERT i Passivated Emitter Rear Contact(PERC), amb l'objectiu d'estudiar els processos de degradació i regeneració associats a la formació de parells bor-oxigen (B-O). L'estudi de l'evolució de Voc amb el temps s'ha constatat una dependència de l'amplitud de degradació i cinètica de regeneració amb l'arquitectura de cèl·lula. En aquest sentit es va observar una degradació significativament superior en les cèl·lules PERC principalment atribuïble a una major sensibilitat a degradacions de la qualitat del substrat. Al mateix temps es va confirmar el potencial dels processos de regeneració induïts per la llum, per suprimir de manera permanent els efectes de la degradaci / Cascant López, M. (2016). INFLUENCIA DE LA COMPOSICIÓN Y ESTRUCTURA DE LOS SUBSTRATOS DE SILICIO MONOCRISTALINO EN EL COMPORTAMIENTO ELÉCTRICO DE LAS CÉLULAS FOTOVOLTAICAS CRISTALINAS DE ALTA EFICIENCIA [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62356

Sustainable Built Environments Senior Capstone Project / Porous concrete pavements have been used in the eastern United States to effectively manage storm water when used as an alternative to impervious surfaces. This paper reviewed a wide body of available literature and research to examine their potential to reduce runoff at the University of Arizona. This study found that their unique structural properties enable them to infiltrate and detain large volumes of water in a stone sub-base below the slab, filtering out many street related contaminants without the need to install additional infrastructure. Porous concrete surfaces may support green development in the southwest where water is both a sensitive and valuable resource. However, long-term structural durability, clogging potential due to dust, and maintenance requirements have yet to be fully understood in this region. This paper then summarizes critical factors that affect the performance of porous concrete and proposes a framework for future study to be conducted by the University of Arizona in a way that would reduce runoff to major campus roads, contribute to a better understanding of sustainable storm water management in the southwest, and demonstrate leadership in environmental stewardship.

Cette étude se concentre sur la compréhension de la physique des instabilités dans différents écoulements de cisaillement, particulièrement la cavité entraînée et la cavité thermocapillaire, où l'écoulement d'un fluide incompressible est assuré soit par le mouvement d’une ou plusieurs parois, soit par des contraintes d’origine thermique.Un code spectral a été validé sur le cas très étudié de la cavité entrainée par une paroi mobile. Il est démontré dans ce cas que l'écoulement transit d'un régime stationnaire à un instationnaire au-delà d'une valeur critique du nombre de Reynolds. Ce travail est le premier à donner une interprétation physique de l'évolution non monotonique du nombre de Reynolds critique en fonction du facteur d'aspect. Lorsque le fluide est entraîné par deux parois mobiles, la cavité entraînée possède un plan de symétrie particulièrement sensible. Des solutions asymétriques peuvent être observés en plus de la solution symétrique au-dessus d'une certaine valeur du nombre de Reynolds. La transition oscillatoire entre la solution symétrique et les solutions asymétriques est expliquée physiquement par les forces en compétition. Dans le cas asymétrique, l'évolution de la topologie permet à l'écoulement de rester stationnaire avec l'augmentation du nombre de Reynolds. Lorsque l'équilibre est perdu une instabilité se manifeste par l'apparition d'un régime oscillatoire dans l'écoulement asymétrique.Dans une cavité thermocapillaire rectangulaire avec une surface libre, Smith et Davis prévoient deux types d'instabilités convectives thermiques: des rouleaux longitudinaux stationnaires et des ondes hydrothermales instationnaires. L'apparition de ses instabilités a été mis en évidence à plusieurs reprises expérimentalement et numériquement. Alors que les applications impliquent souvent plus d'une surface libre, il semble qu'il y ait peu de connaissances sur l'écoulement thermocapillaire entraînée avec deux surfaces libres. Un film liquide libre soumis à des contraintes thermocapillaires possède un plan de symétrie particulier comme dans le cas de la cavité entrainée par deux parois mobiles. Une étude de stabilité linéaire avec deux profils de vitesse pour le film liquide libre est présentée avec différents nombres de Prandtl. Au-delà d'un nombre de Marangoni critique, il est découvert que ces états de base sont sensibles à quatre types d'instabilités convectives thermiques qui peuvent conserver ou briser la symétrie du système. Les mécanismes qui permettent de prédire ces instabilités sont également découverts et interpréter en fonction de la valeur du nombre de Prandtl du fluide. La comparaison avec les travaux de Smith et Davis est faite. Une simulation numérique directe permet de valider les résultats obtenus avec l'étude de stabilité de linéaire. / This study focuses on the understanding of the physics of different instabilities in driven cavities, specifically the lid-driven cavity and the thermocapillarity driven cavity where flow in an incompressible fluid is driven either due to one or many moving walls or due to surface stresses that appear from surface tension gradients caused by thermal gradients. A spectral code is benchmarked on the well-studied case of the lid-cavity driven by one moving wall. In this case, It is shown that the flow transit form a steady regime to unsteady regime beyond a critical value of the Reynolds number. This work is the first to give a physical interpretation of the non-monotonic evolution of the critical Reynolds number versus the size of the cavity. When the fluid is driven by two facing walls moving in the same direction, the cavity possesses a plane of symmetry particularly sensitive. Thus, asymmetrical solutions can be observed in addition to the symmetrical solution above a certain value of the Reynolds number. The oscillatory transition between the symmetric solution and asymmetric solutions is explained physically by the forces in competition. In the asymmetric case, the change of the topology allows the flow to remain steady with increasing the Reynolds number. When the equilibrium is lost, an instability manifests by the appearance of an oscillatory regime in the asymmetric flow. In a rectangular cavity thermocapillary with a free surface, Smith and Davis found two types of thermal convective instabilities: steady longitudinal rolls and unsteady hydrothermal waves. The appearance of its instability has been highlighted repeatedly experimentally and numerically. While applications often involve more than a free surface, it seems that there is little knowledge about the thermocapillary driven flow with two free surfaces. A free liquid film possesses a particular plane of symmetry as in the case of the two-sided lid-driven cavity. A linear stability analysis for the free liquid film with two velocity profiles is presented with various Prandtl numbers. Beyond a critical Marangoni number, it is observed that these basic states are sensitive to four types of thermal convective instabilities, which can keep or break the symmetry of the system. Mechanisms that predict these instabilities are discovered and interpreted according to the value of the Prandtl number of the fluid. Comparison with the work of Smith and Davis is made. A direct numerical simulation is done to validate the results obtained with the linear stability analysis.

This work offers a complete critical overview of the samizdat magazine Sado-Maso1 published in Prague in the years 1983-1986. I tried to make a complete overview and characteristics of the magazine - the main themes of each issue, historical, ideological and literary context of publishing of the Sado-Maso magazine. I also mention publications which were connected with the S-M magazine - independent movies, other samizdat magazines and books. In the Attachment there is article bibliography (containing indexes), covers of the Sado-Maso individual issues, interviews with authors and conterporary witnesses, copies of ,StB' documentary where Sado-Maso magazine was mentioned connected with Klín and Satan Actions. Egon Bondy's essay Zaplaťpánbů za "underground" published exclusively in Sado- Maso Nr. 7 ½ is presented here in commented edition. The goal of this work is to provide information about a not well-known part of Czechoslovak underground culture - a part which still has not been paid much attention on the side of literary history. 1 The title ,Sado-Maso' and the abreviation ,S-M' are used in the same meaning. Keywords SAMIZDAT, MAGAZINES, SADO-MASO, JEN PRO BLÁZNY, OPIUM PRO LID, (ZEN)BUDDHISM, ECOLOGY, ANARCHISM, PSYCHOLOGY, PUNK, MOVIES OF THE SO-CALLED INDEPENDENT PRODUCTION, VISUAL ARTS,...

Esta dissertação investiga numericamente a influência dos efeitos viscosos e elásticos em escoamentos de materiais viscoplásticos no interior de uma cavidade dirigida. O modelo mecânico empregado é constituído pelas equações de conservação de massa e pelo princípio da quantidade de movimento linear, para fluidos incompressíveis, acoplado à equação constitutiva. Esta equação modifica o modelo viscoelástico de Oldroyd-B de modo a acomodar que os tempos de relaxação e retardo do material, bem como sua viscosidade viscoplástica, dependam das mudanças de sua microestrutura. A aproximação numérica do modelo emprega o método multi-campos de Galerkin mínimos-quadrados em termos do tensor de tensão extra, do vetor velocidade e do campo de pressão. Os resultados objetivam a determinção do tamanho e localização das regiões aparentemente não-escoadas do material, bem como sua deformação elástica, intensidade de tensão, e a sua vorticidade no interior da cavidade. Os resultados claramente indicam que o padrão do escoamento é fortemente influenciado pela variação dos efeitos elásticos (variação do tempo de relaxação adimensional, θ0 * ), viscosos (variação do índice de power-law, n) e cinemáticos (variação da velocidade adimensional, U* , do escoamento) no interior da cavidade. / This dissertation investigated numerically the influence of viscous and elastic effects on flows of viscoplastic materials within a lid-driven cavity. The mechanical model used is made up of mass and momentum balance equations, coupled with the constitutive equation. This equation modifies the viscoelastic Oldroyd-B model to accommodate both relaxation and retardation times, and viscosity function, dependent on the microstructure changes. Numerical approximations of the model make use a three-field Galerkin least squares method in terms of the extra stress tensor, velocity vector and pressure field. Computations focus on the determination of the size and position of apparently unyielded regions as well as the elastic deformation, stress intensity, and the vorticity within of the cavity. Results clearly indicate that the flow pattern is strongly influenced by the elastic (variation of the dimensionless relaxation time, θ0 * ), viscous (variation of the power-law index, n) and kinematic (variation of the dimensionless flow velocity, U* ) effects within the cavity.

Die Verdunstung ist die Klimaanlage der Erde. Sie verbindet den globalen Wasserkreislauf mit dem Energiekreislauf. Die Komponenten des Wasser- und Energiekreislaufs stehen für jeden Standort in einem dynamischen Gleichgewicht. Mit der Ausführung von Bauvorhaben wird in das Gleichgewicht eingegriffen. Entscheidend für die Beurteilung der Folgen für die Umwelt sind die langfristigen Auswirkungen. Diese können durch den Vergleich langjähriger mittlerer Jahresbilanzen vor und nach der Bebauung aufgezeigt werden. Bei der Genehmigung neuer Baugebiete müssen diese Auswirkungen ein Entscheidungskriterium werden, wenn der Eingriff in den Naturhaushalt so gering wie möglich gehalten werden soll. Nur die Betrachtung von einzelnen Starkregenereignissen ist nicht ausreichen. Von der Versiegelung der Oberflächen ist die Verdunstung in der Jahresbilanz stärker als die anderen Komponenten des Wasserkreislaufs betroffen. Trotzdem werden bisher bei der Planung neuer Baugebiete hauptsächlich der Oberflächenabfluss und in zunehmendem Maße die Versickerung untersucht. Die Reduzierung der Verdunstung wird zumeist vernachlässigt. Ursache für diese Reduzierung ist die fehlende Zwischenspeicherung des Wassers. Das wirkt sich direkt auf den Energiekreislauf aus, da die nicht für den Verdunstungsprozess benötigte Energie in den bodennahen Schichten bleibt. Im ersten Teil werden die Einflussfaktoren auf die Verdunstung erläutert und ein Überblick über die Berechnungsmethoden gegeben. Im zweiten Teil werden die Oberflächen unbebauter und bebauter Gebiete systematisiert und in Landnutzungsarten unterteilt. Für diese werden die hydrologischen und energetischen Eigenschaften und deren Auswirkungen auf den Wasser- und Energiehaushalt erläutert und die mittleren Jahresbilanzen berechnet. Die tatsächliche Verdunstung wird auf der Basis der Gras-Referenzverdunstung und der Landnutzungsart ermittelt. Ausgangswerte sind langjährige meteorologische Jahresmittelwerte. Die Verdunstung von Wasserflächen wird mit dem Temperaturgleichgewichtsverfahren berechnet. Mit den vorgestellten Verfahren können Einzugsgebiete von Bebauungsplangröße untersucht werden. Es werden Lösungen zur Beibehaltung eines möglichst hohen Verdunstungsanteils in bebauten Gebieten vorgeschlagen. Ansatzpunkt ist dabei stets die Zwi-schenspeicherung des Regenwassers. Am wirkungsvollsten sind dabei Dachbegrünungen, Wasserflächen und Bäume. Das Verfahren wird an zwei Beispielen angewandt - die Erschließung eines Industriegebietes auf einer vorher land- und forstwirtschaftlich genutzten Fläche in Treuen im Vogtland und der Neubau einer Untergrundstation im Zentrum der schwedischen Großstadt Malmö. / Evapotranspiration could be called the air-conditioner of the earth. It is connecting the water and the energy cycle. The components of the water and energy cycle are related to each other in a dynamic system. Urban development is interfering with this system. Changes of the water and energy balance resulting from construction can be calculated on the basis of long-standing annual average balances and compared with the balance in the catchment area before construction. Before granting building permission, the impacts on the water and energy balance should be evaluated in order to minimize interference with nature. Causing long-term impacts must be considered beforehand in planning. Coping only with design storm events does not suffice. Evaporation is more intensely affected by the paving of streets and squares and by constructing buildings then the other components of the water cycle. However, up to now, in the process of design and planning permission of new development areas, the focus is on runoff and, increasingly, on infiltration of rainwater. The large reduction of evaporation is mostly neglected. The reason for the reduction is the lack of buffer storage for water. Thus directly affects the energy cycle. Energy which is not used for evaporation remains in the near-ground layers. In the first part, the factors influencing evaporation are explained and an overview over the methods of calculation is given. In the second part all surfaces of urban and natural areas are systematized and subdivided into types of land use. The hydrological and energy properties as well as their effects on the water and energy balance are elucidated for this types of land use and their average annual balances are calculated. Solutions are presented for retaining in urban areas an evaporation rate as high as possible. Starting point hereby is always the buffer storage of rainwater. Most effective measures are the installation of rooftop greening, open water surfaces and trees. The calculations are performed on the basis of the FAO reference evaporation and the types of land use. Starting values are long-stand average annual meteorologic values. The evaporation of water surfaces is calculated with the temperature balance model. The method is applied to two examples showing the impacts of land use change on water and energy balance: the development of agricultural and forest land in Saxony into an industrial development site, and the impact of the construction of an underground station in the centre of the City Malmö, Sweden.

Le but de cette thèse est de sonder la flexibilité de NCp7 et de Δ(-)PBS, deux bio-molécules impliquées dans le second saut de brin de la transcription inverse du VIH. Deux stratégies expérimentales ont été mises en place. Un nouveau montage de spectroscopie ultra-rapide de fluorescence par down-conversion a été construit. Les dynamiques de quenching de la 2-aminopurine (2Ap), insérée en position 6, 8 et 10 de la boucle Δ(-)PBS ont pu être entièrement résolues à une résolution sub-ps. Pour chaque position, 4 temps de vie ont été révélés. Des mesures d'anisotropie confirment que les deux composantes < 5 ps sont liées à un empilement de la 2Ap avec les Guanines avoisinantes. Cet empilement est site-spécifique, prouvé par l'augmentation significative de leurs amplitudes lorsque la 2Ap est située près de la tige (position 10). La faible proportion de conformations reliées à un quenching collisionnel est significative de la faible exposition des 2Ap au solvant et de l'encombrement général de la boucle. La seconde approche avait pour but d'étudier l'effet du repliement du squelette protéique de [35-50] NCp7 autour de son atome de zinc par CID et par LID. Les spectres CID de la protéine nue sont expliqués par le modèle du proton mobile et une description détaillée d'un schéma de fragmentation spécifique autour du Tryptophane (Trp) a été soulignée, attribué une Lysine voisine. Un seul fragment issu de l'excitation à 266 nm a été identifié, son apparition entre en compétition avec les fragments CID du Trp. L'effet général du repliement autour du Zinc se traduit par une augmentation du taux de fragmentation autour du Trp et par une perte de spécificité pour le reste du spectre.Les flexibilités de Δ(-)PBS et NCp7 ont été respectivement évaluées par spectroscopie ultra-rapide de type down-conversion et par spectrométrie en phase gazeuse. La première méthode nécessite l'utilisation d'une sonde fluorescente non invasive, la 2-aminopurine (2Ap), placée en position 6, 8 et 10 de la boucle Δ(-)PBS. Notre résolution temporelle permet de résoudre entièrement les dynamiques locales de quenching et d'anisotropie de la 2Ap. Les composantes liées au quenching statique et quenching collisionnel ont été discriminées et révèlent les degrés d'empilement / encombrement locaux de la boucle. L'effet du repliement de [35-50] NCp7 autour de son atome de zinc a été étudié par CID et par LID à 266 nm. La protéine nue présente un interessant shéma de fragmentation autour du Tryptophane (Trp), exalté par la complexation avec le zinc, au prix une perte de spécificité pour le reste du spectre. Un seul fragment LID a été identifié, un mécanisme de sa formation est proposé.

A method to solve the Navier-Stokes equations for incompressible viscous flows is proposed. This method is SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm to iteratively solve the two-dimensional laminar steady momentum equations and based upon finite volume method on staggered grids. Numerical tests are performed on several cases of the flow in the lid-driven cavity, as well as of the flow after a backward-facing step with SIMPLE and SIMPLER (SIMPLE Revised) methods. Finally, results are compared qualitatively and quantitatively with numerical and experimental results available in the literature for different Reynolds numbers to validate the methods.

A maioria dos líquidos encontrados na natureza são não-Newtonianos e o estudo do seu comportamento tem uma importância significante em diferentes áreas da engenharia. Entre eles, uma larga classe de materiais que exibem pequena ou nenhuma deformação quando sujeitos a um nível de tensões inferiores a uma tensão limite de escoamento – chamado de comportamento viscoplástico. A presente Dissertação tem como objetivo o estudo numérico de escoamentos bidimensionais em regime permanente de fluidos viscoplásticos não-lineares em uma cavidade forçada. O modelo mecânico é definido pelas equações de conservação de massa e de balanço de momentum acopladas ao modelo viscoplástico recentemente introduzido por Souza Mendes e Dutra – SMD – e é aproximado por um método de elementos finitos multi-campos estabilizado baseado na metodologia de Galerkin mínimos-quadrados que possui como variáveis primais os campos de tensão-extra, velocidade e pressão. As condições de compatibilidade entre os subespaços de elementos finitos para tensão-extra-velocidade e velocidade-pressão são violadas, permitindo assim a utilização de interpolações de igual ordem. O método estabilizado foi implementado no código de elementos finitos para fluidos não-Newtonianos em desenvolvimento no Laboratório de Mecânica dos Fluidos Aplicada e Computacional (LAMAC) da UFRGS. Em diversos trabalhos encontrados na literatura, a superfície de escoamento do material é definida como a região onde o módulo da tensão-extra é igual à tensão limite de escoamento. É mostrado nesta Dissertação que esta metodologia pode conduzir à alguns erros, dado ao grande aumento experimentado pela taxa de cisalhamento em uma pequena faixa de tensões próximas à tensão limite de escoamento. Assim, foi adotada outra metodologia, definindo a superfície de escoamento como a linha onde a taxa de cisalhamento é igual a um valor dado pela relação de parâmetros reológicos do fluido, especificamente a tensão limite de escoamento e a viscosidade Newtoniana para baixas taxas de cisalhamento. Nas simulações numéricas realizadas, o número de salto, J, o coeficiente de power-law, n, e a vazão adimensional, U*, são variados de forma a avaliar de que modo influenciam na dinâmica de escoamentos viscoplásticos. Os resultados obtidos estão de acordo com a literatura e atestam a estabilidade da formulação empregada. / Non-Newtonian fluids are the majority of liquids found on the nature and the study of their behavior has a significant importance on different areas of engineering. Among them, there is a wide class of materials that exhibits little or no deformation when subjected to a stress level behind an apparent yield stress – called the viscoplastic behavior. The present thesis aimed to a numerical study of two dimensional steady state laminar flows of non-linear viscoplastic fluids in a lid-driven cavity. The mechanical model was defined by the mass conservation and momentum balance equations coupled to the recently introduced Souza Mendes and Dutra – SMD – viscoplastic model and has been approximated by a stabilized multi-field finite element method based on the Galerkin least-squares methodology, having as primal variables the extra-stress, velocity and pressure fields. In this way, the compatibility conditions between the extra-stressvelocity and pressure-velocity (Babuška-Brezzi condition) finite element subspaces are violated, allowing to use equal-order finite element interpolations. The stabilized method has been implemented in the finite element code for non-Newtonian fluids under development at the Laboratory of Applied and Computational Fluid Mechanics (LAMAC) of UFRGS. In several works found on the literature, the yield surface of the material is defined as the region where the stress modulus is equal to the yield stress. Is shown in this work that this methodology can lead to some errors, due to the large strain rate increasing in a small range of values of stress on the vicinity of the yield stress. Therefore, it was adopted another approach, defining the yield surface as the line where the strain rate is equal to a value given by the relation of the rheological parameters of the fluid, namely the yield stress and the viscosity at low shear rates. In the performed numerical simulations, the jump number, J, the the power-law coefficient, n,and the non-dimensional flow rate, U*, are ranged in order to evaluate how they the influence on the viscoplastic fluid dynamics have been investigated. All results found were in accordance with the affine literature and attests the good stability features of the formulation.