"The present work is a study of the low inertia spreading dynamics of initially spherical viscous droplets on a planar interface. The droplets are affected by gravity, surface tension and viscous forces and are modeled as two-dimensional axisymmetric bodies. The main focus of this study is the examination of the dependence of droplet stability, equilibrium shape and fluid motion within the drop on the relative magnitude of these forces. The dynamics are modeled using the unsteady, non-linear Navier-Stokes equations for an incompressible fluid. The spreading of a droplet on a solid surface is modeled with both a no-slip and a partial-slip boundary condition. In addition, the spreading of a droplet on another identical drop (two-drop problem) is modeled to study the problem without the contact point singularity. The governing equations are solved numerically using the Mixed Galerkin Finite Element formulation, augmented by the use of the Newton-Raphson iteration scheme to effectively treat the non-linearities of the problem. The Generalized Eulerian Lagrangian formulation is adopted for the treatment of the moving free surface of the droplet. Computations are performed for capillary numbers ranging from 0.01 to 100 and for Reynolds numbers from 0.005 to 50, where the velocity scale is based on the droplet radius and the gravitational acceleration. For the droplet spreading on a solid surface, three distinct behaviors are observed~: for low Reynolds numbers and sufficiently high capillary numbers, droplets deform to a stable, equilibrium shape; for higher Reynolds numbers, an oscillatory droplet behavior occurs; at still higher Reynolds numbers, the droplets shatter. Very often, a recirculation is induced near the contact point just before the droplet shatters, which is also observed for the case of stable oscillating droplets. When a partial-slip boundary condition is applied, it is observed that the stability of the droplet and the rate at which the droplet attains the static contact angle depend strongly on the velocity of slip of the droplet with respect to the solid surface at the contact point. For the two-drop problem, only two distinct behaviors are observed: for low Reynolds numbers and high capillary numbers, the droplet retains a near-spherical shape and remains stable; while for higher Reynolds numbers, the droplet deforms to a high extent and becomes unstable."

Accelerated soil erosion is one of the major threats to agricultural production in Ethiopia and the Harerge region is not exceptional. It is estimated that about 1.5 billion tones of soil is being eroded every year in Ethiopia. In the extreme cases, especially for the highlands, the rate of soil loss is estimated to reach up to 300 t ha-1yr-1 with an average of about 70 t ha -1yr-1 which is beyond any tolerable level. The government have made different attempts to avert the situation since 1975 through initiation of a massive program of soil conservation and rehabilitation of severely degraded lands. Despite considerable efforts, the achievements were far bellow expectations. This study was aimed at assessing the effect of some soil properties, rainfall intensity and slope gradients on surface sealing, soil erodibility, runoff and soil loss from selected sites in the Harerge region, eastern Ethiopia, using simulated rainfall. Soil loss was also estimated for the sites using Soil Loss Estimation Model for Southern Africa (SLEMSA) and the Universal soil Loss Equation (USLE). Moreover, the effectiveness of various rates and patterns of wheat residue mulching in controlling soil loss was also evaluated for one of the study sites, (i.e. Regosol of Alemaya University), under both rainfall simulation and field natural rainfall conditions. For most of the erosion parameters, the interaction among soil texture, slope gradient and rainfall intensity was significant. In general however, high rainfall intensity induced high runoff, sediment yield and splash. The effect of slope gradients on most of the erosion parameters was not significant as the slope length was too small to bring about a concentrated flow. The effect of soils dominated by any one of the three soil separates on the erosion parameters was largely dependent on rainfall intensity and slope gradient. The soils form the 15 different sites in Harerge showed different degrees of vulnerability to surface sealing, runoff and sediment yield. These differences were associated with various soil properties. Correlation of soil properties to the erosion parameters revealed that aggregate stability was the main factor that determined the susceptibility of soils to sealing, runoff and soil loss. This was in turn affected by organic carbon content, percent clay and exchangeable sodium percentage (ESP). Soils with relatively high ESP such as those at Babile (13.85) and Gelemso (7.18) were among the lowest in their aggregate stability (percent water stable aggregates of 0.25 –2.0mm diameter); and have highest runoff and sediment yield as compared to other soils in the study. Similarly, most of those soils with relatively low ESP, high organic carbon content (OC%) and high water stable aggregates such as Hamaressa, AU (Alemaya University) vertisol and AU regosol were among the least susceptible to sealing and interrill erosion. Nevertheless, some exceptions include soils like those of Hirna where high runoff was recorded whilst having relatively high OC%, low ESP and high water stable aggregates. Both the SLEMSA and USLE models were able to identify the erosion hazards for the study sites. Despite the differences in the procedures of the two models, significant correlation (r = 0.87) was observed between the values estimated by the two methods. Both models estimated higher soil loss for Gelemso, Babile, Karamara and Hamaressa. Soil loss was lower for Diredawa, AU-vertisol and AU-Alluvial all of which occur on a relatively low slope gradients. The high soil loss for Babile and Gelemso conforms with the relative soil erodibility values obtained under rainfall simulation suggesting that soil erodibility, among others, is the main factor contributing to high soil loss for these soils. The difference in the estimated soil losses for the different sites was a function of the interaction of the various factors involved. Though the laboratory soil erodibility values were low to medium for Hamaressa and Karamara, the estimated soil loss was higher owing to the field topographic situations such as high slope gradient. SLEMSA and USLE showed different degrees of sensitivities to their input variables for the conditions of the study sites. SLEMSA was highly sensitive to changes in rainfall kinetic energy (E) and soil erodibility (F) and less sensitive to the cover and slope length factors. The sensitivity of SLEMSA to changes in the cover factor was higher for areas having initially smaller percentage rainfall interception values. On the other hand, USLE was highly sensitive to slope gradient and less so to slope length as compared to the other input factors. The study on the various rates and application patterns of wheat residue on runoff and soil loss both in the laboratory rainfall simulation and under field natural rainfall conditions revealed that surface application of crop residue is more effective in reducing soil loss and runoff than incorporating the same amount of the residue into the soil. Likewise, for a particular residue application method, runoff and soil loss decreased with increasing application rate of the mulch. However, the difference was not significant between 4 Mg ha-1 and 8 Mg ha-1 wheat straw rates suggesting that the former can effectively control soil loss and can be used in areas where there is limitation of crop residues provided that other conditions are similar to that of the study site (AU Regosols). The effectiveness of lower rates of straw (i.e. less than 4 Mg ha-1 ) should also be studied. It should however be noted that the effectiveness of mulching in controlling soils loss and runoff could be different under various slope gradients, rainfall characteristics and cover types that were not covered in this study. Integrated soil and water conservation research is required to develop a comprehensive database for modelling various soil erosion parameters. Further research is therefore required on the effect of soil properties (with special emphasis to aggregate stability, clay mineralogy, exchangeable cations, soil texture and organic matter), types and rates of crop residues, cropping and tillage systems, mechanical and biological soil conservation measures on soil erosion and its conservation for a better estimation of the actual soil loss in the study sites. Copyright 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bobe, BW 2004, Evaluation of soil erosion in the Harerge region of Ethiopia using soil loss models, rainfall simulation and field trials, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-08022004-141533 / > / Thesis (PhD (Soil Science))--University of Pretoria, 2004. / Plant Production and Soil Science / unrestricted

<p>  </p> <p>Cavitation, liquid slosh, and splashes are ubiquitous in science and engineering. However, these phenomena are not fully understood. Yet to date, we do not understand when or why sometimes the splash seals, and other times does not. Regarding cavitation, a high temporal resolution method is needed to characterize this phenomenon. The low temporal resolution of experimental data suggests a model-based analysis of this problem. However, high-fidelity models are not always available, and even for these models, the sensitivity of the model outputs to the initial input parameters makes this method less reliable since some initial inputs are not experimentally measurable. As for sloshing, the air-liquid interface area and hydrodynamic stress for the liquid slosh inside a confined accelerating cylinder have not been experimentally measured due to the challenges for direct measurement.</p>

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Une étude tridimensionnelle du déferlement plongeant des vagues est proposée sur la base de résultats obtenus par Simulation des Grandes Echelles des équations de Navier-Stokes en formulation diphasique. Après une étude bibliographique situant le problème, la première partie du travail est consacrée au développement et à la validation des méthodes numériques employées pour la résolution des équations. Dans une seconde partie de travail, l'outil numérique est exploité afin d'étudier différents problèmes bidimensionnels de propagation d'ondes solitaires. La dernière partie du travail consiste à appliquer les méthodes numériques au déferlement tridimensionnel d'ondes sinusoïdales périodiques de larges amplitudes. Une description complète du phénomène est proposée, incluant la génération du splash-up ainsi que la dissipation de l'énergie par les différentes structures turbulentes présentes dans l'écoulement.

La culture d’associations de variétés sensibles et résistantes au sein d’une même parcelle permet de réduire la propagation des maladies fongiques foliaires aériennes. L’architecture des plantes a un impact sur la dispersion de spores et le microclimat, mais est rarement prise en compte dans la conception des associations. L’objectif de cette thèse était de comprendre le rôle joué par l’architecture dans des associations de variétés différant par leur niveau de résistance à une maladie dispersée par éclaboussement, la septoriose du blé, causée par Zymoseptoria tritici. Une expérimentation en conditions contrôlées a permis de quantifier des relations entre interception de spores et architecture des couverts. Des différences de densité entre couverts purs et associés ont donné lieu à une réduction du niveau de maladie sur les plantes sensibles cultivées en association par rapport à celles cultivées pures. Lors d’une expérimentation au champ, les associations de variétés de hauteurs de tiges contrastées étaient moins malades que celles ayant des hauteurs similaires. Ces résultats ont été mis en relation avec des effets de l’architecture sur la dispersion de spores et la durée d’humectation au sein des couverts. Une approche de modélisation spatialement explicite a permis d’identifier des mécanismes de dispersion par éclaboussement liés à l’architecture des couverts associés. Dans des associations de variétés de hauteurs différentes, la quantité d’inoculum éclaboussée dépendait de la surface foliaire présente au dessus des feuilles malades (effet parapluie). La quantité d’inoculum interceptée par un étage foliaire était liée à la différence de hauteur entre la source d’inoculum et l’étage foliaire (effet hauteur). Les différences de hauteur de plantes entre variétés d’une association ont modulé l’interception de spores par des feuilles résistantes (effet barrière). Nos résultats suggèrent qu’une prise en compte de l’architecture des variétés dans la conception des associations variétales permettrait de mieux maîtriser les maladies par éclaboussement. / Growing mixtures of susceptible and resistant cultivars in the same field makes it possible to reduce the propagation of airborne fungal plant diseases. Plant architecture has an impact on spore dispersal or microclimate, but is rarely taken into account in mixture design. The objective of this work was to understand the role of canopy architecture in mixtures of cultivar of different levels of resistance to a disease dispersed by rain-splash, septoria tritici blotch, caused by Zymoseptoria tritici. A controlled conditions experiment made it possible to quantify relationships between spore interception and canopy architecture. Differences of canopy density between pure stands and mixtures led to a reduction in disease on susceptible plants grown in mixture, compared to the susceptible pure stand. During a field experiment, mixtures of cultivars with contrasted stem height were less diseased than those with similar stem height. These results were related to the effect of canopy architecture on spore dispersal and leaf wetness duration. A spatially explicit modeling approach made it possible to identify splash dispersal mechanisms related to the architecture of mixed canopies. In mixtures of cultivar with diverse plant height, the amount of splashed inoculum depended on leaf area located above diseased leaves (umbrella effect). The amount of inoculum intercepted by a leaf layer was related to its difference of height between the inoculum sources (height effect). Differences of plant height between cultivars composinga mixture modulated the interception of spores by resistant leaves, providing an increased protection of susceptible leaves (barrier effect). Our results suggest that considering cultivar architecture in the design of cultivar mixtures could make it possible to improve the management of splash-dispersed diseases.

The consumption of heating energy in existing buildings represents a large share of total national energy consumption and therefore contributes significantly to the production of climate-damaging CO2. In order to stop climate change and make a substantial contribution to climate protection, heating energy consumption must therefore be reduced urgently. The most effective way to do this is to maintain and renovate uninsulated buildings. Thermal insulation is and remains one of the most important measures for reducing energy demand in buildings. Interior insulation has become increasingly important in recent years. This is due to the fact that a considerable part of the building stock, which can easily be insulated from the outside, has already been renovated. On the other hand, the proportion of remaining buildings where, for various reasons, only interior insulation is possible or even more advantageous, is becoming larger and larger. The surface area of the exterior walls accounts for a large proportion of the total building and thus of the potential for energy optimisation. In order to achieve optimal renovation success, the presented concept is developed on the basis of the existing condition of the building.:1 Introduction 1 2 Planning phases 2 3 Façade renovation concept 5 Monument status 5 Documentation of the condition of the façade 5 General measures on the existing structure 6 Notes on driving rain / splash water protection 10 Measures for plaster facades 15 Measures for exposed masonry 16 4 Development of an insulation concept 19 Determination of desired insulation standard 19 Selection of possible insulation systems 20 Overview of the most important evaluation criteria 28 Hygrothermal behaviour of typical insulation systems 28 5 Dimensioning and verification 29 Verification free / deemed to satisfy interior insulations according to DIN 4108-3 30 Simplified verification for internal insulation 30 Extension of the simplified verification – classification of vapour permeable, capillary-active insulation systems 31 Verification by hygrothermal simulation 34 Simulation tables for typical applications / approvals by manufactures 36 6 Dimensioning / execution of connection details 37 General dimensioning recommendations 37 Typical connection details 39 Selection criteria for the detailed design 40 Constructive tips for interior insulation measures 43 Hygrothermal simulation of connection details 46 7 Literature 47 A Appendix 49 Description of waterproofing systems 49 Insulation systems investigated for hygrothermal behaviour (from EnEffID) 53 Preparation of a simplified verification according to WTA guideline 6-4 57 Boundary conditions for the simplified verification for the classification of vapour permeable, capillary-active insulation materials 58 Evaluation of the classification of vapour permeable, capillary-active insulation materials 59 Characteristic values, boundary conditions and evaluation criteria for hygrothermal simulations 60 Application example for a one-dimensional hygrothermal design 63 Application examples for the hygrothermal design of connection details 67 Typical connection details 74 Flowchart Facade renovation concept 101 Flowchart Insulation concept 102

Der Verbrauch von Heizenergie in Bestandsgebäuden stellt einen großen Anteil am gesamten nationalen Energieverbrauch dar und trägt deshalb maßgeblich zur Produktion von klimaschädlichem CO2 bei. Um den Klimawandel aufzuhalten und einen substanziellen Beitrag zum Klimaschutz zu leisten, muss deshalb der Heizenergieverbrauch dringend reduziert werden. Dies geschieht am effektivsten durch den Erhalt und die energetische Sanierung von ungedämmten Gebäuden. Wärmedämmung ist und bleibt eine der wichtigsten Maßnahmen zur Senkung des Energiebedarfs im Gebäudebereich. Dabei gewinnt die Innendämmung in den letzten Jahren immer mehr an Bedeutung. Dies liegt daran, dass ein nennenswerter Teil des Gebäudebestands, der leicht von außen gedämmt werden kann, bereits saniert ist. Der Anteil der verbleibenden Gebäude, bei denen aus verschiedenen Gründen nur eine Innendämmung möglich oder auch vorteilhafter ist, wird im Gegenzug immer größer. Die Fläche der Außenwände nimmt beim Gesamtgebäude und damit beim energetischen Optimierungspotenzial einen großen Anteil ein. Um einen optimalen Sanierungserfolg zu erzielen, erfolgt die Konzepterstellung auf Grundlage des vorgefundenen Zustandes des Bestandsgebäudes.:1 Einleitung 1 2 Planungsphasen 2 3 Fassadensanierungskonzept 5 3.1 Denkmalstatus 5 3.2 Dokumentation des Fassadenzustandes 5 3.3 Generelle Maßnahmen an der Bestandskonstruktion 6 3.4 Hinweise zum Schlagregen- / Spritzwasserschutz 10 3.5 Maßnahmen bei Putzfassaden 15 3.6 Maßnahmen für Sichtmauerwerk 16 4 Erstellung eines Dämmkonzeptes 19 4.1 Festlegung des gewünschten Dämmstandards 19 4.2 Auswahl möglicher Dämmsysteme 20 4.3 Überblick über die wichtigsten Bewertungskriterien 28 4.4 Hygrothermisches Verhalten typischer Dämmsysteme 28 5 Dimensionierung und Nachweis 29 5.1 Nachweisfreie bzw. als erfüllt erachtete Konstruktionen gemäß DIN 4108-3 30 5.2 Vereinfachter Nachweis für Innendämmungen 30 5.3 Erweiterung des vereinfachten Nachweises - Klassifizierung diffusionsoffener kapillaraktiver Dämmsysteme 31 5.4 Nachweis durch hygrothermische Simulation 34 5.5 Simulationstabellen für typische Anwendungsbereiche / Freigaben durch Hersteller 36 6 Dimensionierung / Ausführung von Anschlussdetails 37 6.1 Allgemeine Dimensionierungsempfehlungen 37 6.2 Typische Anschlussdetails 39 6.3 Auswahlkriterien für die Detailbemessung 40 6.4 Konstruktive Hinweise bei Innendämmmaßnahmen 43 6.5 Hygrothermische Simulation von Anschlussdetails 46 7 Literaturverzeichnis 47 A Anhang 49 A I Beschreibung von Abdichtungssystemen 49 A II Untersuchte Dämmsysteme zum hygrothermischen Verhalten (aus EnEffID) 53 A III Erstellung eines vereinfachten Nachweises nach WTA-Merkblatt 6-4 57 A IV Randbedingungen für den vereinfachten Nachweis zur Klassifizierung diffusionsoffener, kapillaraktiver Dämmmaterialien 58 A V Auswertung der Klassifizierung diffusionsoffener, kapillaraktiver Dämmmaterialien 59 A VI Kennwerte, Randbedingungen und Bewertungskriterien für hygrothermische Simulationen 60 A VII Anwendungsbeispiel für eine eindimensionale hygrothermische Bemessung 63 A VIII Anwendungsbeispiele für die hygrothermische Bemessung von Anschlussdetails 67 A IX Typische Anschlussdetails 74 A X Ablaufschema Fassadensanierungskonzept 101 A XI Ablaufschema Dämmkonzept 102

L’ascomicete Guignardia bidwellii, agente causale del marciume nero della vite, è un patogeno economicamente importante in alcuni areali viticoli. La conoscenza, disponibile sul marciume nero dell’uva, è stata recuperata dalla letteratura, analizzata e sintetizzata per sviluppare un modello meccanicistico del ciclo di vita del patogeno, guidata dalle variabili meteorologiche e dalla fenologia della vite, e basata sull'analisi dei sistemi. Il modello è stato poi valutato per la sua capacità di rappresentare il sistema reale e la sua utilità per la comprensione di epidemie di marciume nero su foglie e grappoli in un vigneto del Nord Italia, nel 2013 al 2015. Successivamente, le mancanze di conoscenza sono state analizzate, studiate e quindi colmate attraverso specifici esperimenti. In un primo passo, le dinamiche dell’inoculo primario e dei modelli di dispersione (di entrambi ascospore e conidi) da mummie svernate sono state studiate in un vigneto sperimentale per tre anni. In un secondo passo, l'effetto della temperatura e dell'umidità sulla formazione di picnidi di G. bidwellii e la successiva estrusione di cirri, nelle lesioni su foglia, la produzione e la germinazione dei conidi (inoculo secondario), e la lunghezza del periodo di latenza sono stati studiati sia in condizioni di campo che in ambiente controllato. In un terzo passo, sono stati condotti studi in ambiente controllato per studiare la produzione di conidi di G. bidwellii sulle lesioni di foglie, influenzata da lavaggi ripetuti e alternando periodi di secco ed umido. Il modello epidemiologico sviluppato in questa tesi può essere utilizzata da viticoltori come strumento predittivo per la pianificazione di trattamenti fungicidi nei vigneti. / The ascomycete Guignardia bidwellii, causal agent of black-rot on grapevines, is an economically important pathogen in some viticultural areas. The available knowledge on black-rot of grape was retrieved from literature, analyzed, and synthesized to develop a mechanistic model of the life cycle of the pathogen, driven by weather and vine phenology, and based on the systems analysis. The model was then evaluated for its ability to represent the real system and its usefulness for understanding black-rot epidemics on leaves and bunches in a vineyard of north Italy, in 2013 to 2015. Thereafter, weaknesses in our knowledge were analysed and studied through specific experiments. In a first step, dynamics of primary inoculum and dispersal patterns (both ascospores and conidia) from overwintered grape mummies were investigated in an experimental vineyard during three years. In a second step, the effect of temperature and humidity on the formation of G. bidwellii pycnidia and the extrusion of cirri in grape leaf lesions, production and germination of conidia (secondary inoculum), and the length of the latency period were studied under both environmental and controlled conditions. In a third step, environmental-controlled studies were conducted to investigate the production course of G. bidwellii conidia on grape leaf lesions as influenced by repeated washing events and alternate dry and wet periods. The model developed in this thesis can be used by vinegrowers as a predictive tool for scheduling fungicide sprays in the vineyards.

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