During the last years perovskite materials have taken the photovoltaic community by storm, bringing promises of solar cells with efficiencies comparable to conventional silicon devices but at a lower price. However perovskite solar cells so far are facing two main obstacles, they are unstable in the presence of air, moisture and heat and they are usually toxic due to being based on lead-halide materials. This has spurred investigations into alternative materials with similar properties but without the mentioned drawbacks. Just next to Pb in the periodic table is bismuth (Bi) with just one more electron in its outer-shell, Bi however is less toxic. In this work the perovskite derived compounds of Ag-Bi-I and Cu-Bi-I are characterized and their properties as light absorbing material in solar cell devices are investigated. Devices are prepared by preparing Ag-Bi-I and Cu-Bi-I solutions which are then spin-coated on top of a mesoporous TiO2. A conducting polymer, P3HT, was then deposited and serve as hole transport material. For Ag-Bi-I, the molar ratios of AgI:BiI3= 1:2 and 2:1 were observed with SEM to form homogeneous crystal films with one dominating crystal phase, which by XRD could be determined to most likely have formed a cubic AgBi2I7 crystal structure for the 1:2 ratio and a hexagonal Ag2BiI5 crystal structure for the 2:1 ratio. The Cu-Bi-I materials were not successfully synthesized to form homogeneous films with a dominating crystal phase, although several molar ratios were investigated. All investigated compositions of both Cu and Ag devices showed to in principle work as light absorbing materials, the best Ag-Bi-I device showing a PCE of 1.92%, for the 2:1 ratio, while the Cu-Bi-I devices at best reached 0.32% for a ratio of 1:1. XPS measurements were carried out with a classical in-house XPS using an Al K X-ray source of 1486.7 eV as well as at the Diamond Light Source (UK) synchrotron facility using photon energies of 758 eV and 2200 eV so that a depth resolution of the composition could be observed. Because of their inhomogeneous crystal formation, XPS couldn’t give much useful quantitative information regarding the Cu devices. For Ag devices it was observed that the stoichiometry at the extreme surface deviated from that predicted by XRD, but deeper into the surface the relative ratio of elements approach the predicted ones, hinting towards a different structure at the outermost surface or a lot of surface defects. For all samples, two types of bismuth atoms were observed, metallic (Bi0) as well as a cationic (Bi+x), the later corresponding to Bi atoms which are partaking in the crystal bond. The ratio of metallic to cationic Bi was observed to decrease notably just a few nm below the extreme surface. The effect of the high presence of metallic Bi on final device performance was not concluded with certainty but not believed to be positive. By varying the annealing temperature, after spin coating the light absorber solution on the TiO2, it was observed that lower temperature resulted in a lower ratio of metallic Bi. As final conclusions, it was said that the synthesis method of Cu-Bi-I needs to be improved before those materials can be studied further. The synthesis of Ag-Bi-I is showing much more promise and one can start looking into further optimizing their final device structure to boost efficiency. Both Cu-Bi-I and Ag-Bi-I devices are relatively simple, cheap and energy efficient (with annealing temperatures around 150C) to produce, great aspects for solar cells. UVVis measurements showed they have band gaps around 1.6-1.7 eV which makes them a great potential material for use in tandem solar cells together with a semiconductor of lower band gap such as silicon.

Philosophiae Doctor - PhD / This study is aimed at investigating the feasibility of using the radiometric technique as an alternative to traditional methods for determining soil physico-chemical parameters which are important for terroir characterization. In-situ and ex-situ radiometric analyses of soil from three vineyard blocks of Simonsig Wine Estate in the Stellenbosch district (Western Cape, South Africa) were studied. A mobile MEDUSA gamma-ray detection system comprising a CsI(Na) crystal (length 15 cm, diameter 7 cm) and associated electronics mounted on a portable trolley were used for partial terroir characterisation. Thereafter activity concentrations of 40K, 232Th series and 238U series in soil (top ~30 cm) from the measured MEDUSA spectra (0 - 3 MeV) were extracted by means of the full-spectrum analysis (FSA) method. A lead-shielded HPGe detector was used for analyzing collected soil samples while soil physico-chemical parameters were analysed using standard methods at research and commercial laboratories. / South Africa

L'élimination des protéines est une étape clé lors de la production du vin blanc afin d'éviter l'apparition éventuelle d'un voile inoffensif mais inesthétique. Des solutions de rechange à l'utilisation de la bentonite sont activement recherchées en raison des problèmes technologiques, organoleptiques et de durabilité associés à son utilisation. Dans cette étude, MpAPr1, une protéase aspartique extracellulaire préalablement isolée et partiellement caractérisée à partir de la levure Metschnikowia pulcherrima, a été clonée et exprimée de manière hétérologue dans la levure Komagataella pastoris. Les propriétés enzymatiques de MpAPr1 ont été initialement caractérisées dans un extrait brut. Après plusieurs essais faisant appel à différentes techniques, MpAPr1 a été purifié avec succès par chromatographie échangeuse de cations. Son activité contre les protéines de raisin a été initialement testée dans une solution modèle dans des conditions environnementales optimales pour l'activité de MpAPr1 puis dans celles qui règnent lors de la vinification. Ensuite, l'activité de MpAPr1 a été évaluée dans du moût de raisin et au cours de la fermentation alcoolique. La présence de MpAPr1, supplémenté au moût de raisin, a entraîné une dégradation partielle des protéines de raisin tout au long de la fermentation et une légère différence dans la composition en composés volatils du vin. L'étude a confirmé que les protéases aspartiques pourraient représenter une alternative à la bentonite pour l'industrie du vin et que les levures non-Saccharomyces telles que M. pulcherrima pourraient avoir un impact bénéfique sur les propriétés du vin. / Protein removal is a key step during the production of white wine in order to avoid the possible appearance of a harmless but unsightly haze. Alternatives to the use of bentonite are actively sought because of technological, organoleptic and sustainability issues associated with its use. In this study, MpAPr1, an extracellular aspartic protease previously isolated and partially characterised from the yeast Metschnikowia pulcherrima, was cloned and expressed heterologously in Komagataella pastoris. Enzymatic properties of MpAPr1 were initially characterised in a crude extract. After several attempts using different techniques, MpAPr1 was successfully purified via cation exchange chromatography. Its activity against haze-forming grape proteins was initially tested in a model solution under optimal environmental conditions for MpAPr1 activity and under those occurring during winemaking. Thereafter, MpAPr1 activity was evaluated in grape must and throughout alcoholic fermentation. The presence of MpAPr1, supplemented to grape must, resulted in the partial degradation of grape proteins throughout fermentation and ultimately in a slight difference in the wine’s composition in volatile compounds. The study provides further evidence that aspartic proteases could represent a potential alternative to bentonite for the wine industry and that non-Saccharomyces yeasts such as M. pulcherrima could have a beneficial impact on wine properties.

Ce travail porte sur la caractérisation d'anches simples utilisées pour la clarinette ou le saxophone. Sachant que les musiciens perçoivent des différences importantes dans la qualité des anches de caractéristiques identiques (même marque, coupe et force), cette thèse propose des nouveaux outils pour la caractérisation des anches en situation de jeu.Un bec instrumenté utilisant des capteurs embarqués est développé de façon à mesurer le déplacement de l'anche et la différence de pression de part et d’autre de l'anche. À partir de ces signaux, il est possible d'estimer des paramètres d'anche associés à différents modèles physiques. Les résultats obtenus montrent que la complexité du modèle décrivant le comportement de l'anche doit augmenter avec la nuance de jeu. Le bec instrumenté est utilisé dans une campagne de mesures comportant 7 musiciens et 20 anches, et permet de quantifier la variabilité des résultats due aux musiciens. Des tests subjectifs sont réalisés avec ces mêmes musiciens, et montrent que les différences entre les anches se réduisent à une seule dimension (facilité de jeu ou timbre). Les corrélations entre les descripteurs subjectifs et les paramètres objectifs mesurés sont étudiées afin de mieux comprendre les différences perçues entre les anches, permettant le développement d'un modèle prédictif de la qualité des anches.De façon à éviter la variabilité produite par le musicien, une bouche artificielle aspirante est développée. La comparaison des mesures réalisées par la bouche artificielle et par un musicien permet d'identifier la plage de fonctionnement optimale où la bouche artificielle imite au mieux le jeu du musicien. / This work deals with the characterisation of single cane reeds used for clarinet or saxophone. Musicians perceive important differences of quality between reeds of the same brand, cut and strength. This thesis proposes new tools for reed characterisation in playing conditions.An instrumented mouthpiece is developed to enable the measurement of reed displacement and pressure difference on both sides of the reed using embedded sensors. From these signals, it is possible to estimate reed parameters of different physical models. Results reveal that the complexity of the physical model describing the reed behaviour must increase with the dynamic level.The instrumented mouthpiece is used in a measurement campaign involving 7 players and 20 reeds, quantifying the variability of the results due the musicians. Subjective tests conducted with these musicians show that reeds can be mainly described by one dimension (ease of playing or timbre). The correlations between the subjective descriptors and the measured objective parameters are studied to better understand the perceived differences between reeds, developing a predictive model of reed quality.In order to avoid the variability of the musician, an aspirating artificial mouth is developed. It uses the instrumented mouthpiece and it can be played by a musician or artificially. The comparison of the measurements made in both cases allows for the identification of the optimal working range in which the artificial mouth best reproduces the musician's playing according to intonation and playing level.

Les transferts d’humidité dans les matériaux de construction ont une influenceimportante sur leur durabilité et sur les performances hygriques et thermiques desbâtiments. De nombreux mécanismes d’endommagement chimiques et physiquesde ces matériaux sont en effet dus à l’infiltration d’eau. En conséquence, leur structureporeuse peut évoluer au cours du temps, et des fissures microscopiques commemacroscopiques peuvent s’y développer. La description des matériaux à l’échelle microscopiqueest cependant une source d’erreur importante dans les codes de simulationactuels des transferts d’humidité et de chaleur, notamment en raison du faitque lesmilieux sont considérés comme homogènes, et que les effets du vieillissementdes matériaux sont négligés. Il importe donc de trouver un moyen d’inclure les effetsde l’endommagement dans les simulations de transferts d’humidité et de chaleurà l’échelle du bâtiment. Des méthodes existent pour la prédiction du comportementde milieux soumis à des sollicitations hygriques et mécaniques, mais supposent quel’ensemble des facteurs extérieurs influant sur l’endommagement soient connus toutau long des simulations.Une nouvelleméthodologie est proposée ici pour compléter ces approches prédictives,en combinant des mesures expérimentales d’endommagement avec la simulationde transferts couplés d’humidité et de chaleur. Une étude préliminaire a d’abordété menée, consistant à mesurer la perméabilité vapeur équivalente d’éprouvettes demortier multi-fissurées. Cette démarche a permis d’identifier les besoins expérimentauxet numériques de la suite du travail, visant à modéliser les écoulements dans unréseau discret de fissures sur la base de leur caractérisation. Une méthodologie expérimentalecombinant corrélation d’images numériques et émissions acoustiques aensuite été développée, permettant de disposer de cartographies d’endommagementet de proposer une démarche pour lamesure de réseaux de fissures dans lesmatériauxde construction en place. La méthode optique, associée à une procédure de traitementd’images, a permis de disposer de données précises de la géométrie de réseauxde fissures. De plus, une méthode a été proposée pour permettre l’interprétation desmesures d’émissions acoustiques en termes de quantification, localisation et identificationdes phénomènes d’endommagement.Un code de simulation a ensuite été écrit, permettant d’intégrer ces mesures defissuration dans la modélisation des écoulements couplés d’humidité et de chaleuren milieu poreux. Ce modèle a été validé sur la base de mesures expérimentales : lacorrélation d’images numériques a été appliquée durant la fracturation d’éprouvettesde béton, dans lesquelles l’infiltration d’eau a ensuite été suivie par radiographie auxrayons X. Les résultats numériques obtenus sont en bonne conformité avec lesmesuresexpérimentales en termes de prédiction de la concentration d’eau en deux dimensions.Enfin, laméthodologie a été appliquée à une série de cas test, dans le but demodéliserles performances hygrothermiques de parois multi-couches, incluant des matériauxendommagés, soumises à des conditions climatiques réelles. On a ainsi pu estimer les conséquences potentielles de l’endommagement sur l’accumulation d’eau dans desparois, sur l’amplitude des cycles de sorption et de séchage, ainsi que sur les transfertsthermiques. / An importantmatter in the field of building physics is the questioning of how wellbuildings sustain ageing, and how their overall efficiency evolves over their lifetime.Many causes for degradation are carried by moisture transfer through these porousmaterials. Indeed, infiltratedwatermay transport chemicals, altermechanical properties,and cause freeze thaw damage or mould development. It may also affect thermalproperties and energetic efficiency, as well as the health and comfort of the occupants.The understanding of how moisture transfer properties evolve during the lifespan ofbuildingmaterials is however far fromcomplete. The pore structure of amaterial itselfmay change over time, or be altered by cracks and defects caused bymechanical loadingand aggravated bymoisture-induced degradation. All sizes of fracturesmay have astrong impact on heat and moisture flow in the building envelope, and their influenceis to be accounted for in any long-termperformance assessment, not only of buildingand building components,but of any built structure in general. A considerable amountof work has already been performed in order to allow predicting the hygrothermal behaviourof buildings over longer periods of time. However, an accurate prediction of allranges of damage in a building component, from microscopic to macroscopic cracks,supposes an extensive knowledge of all damage-inducing, time-varying boundary conditionsof the problem during the simulation time. This also implies high computationalcosts, as well as important needs formaterial characterisation.As a complement to these predictive methods, a new approach was undertaken,combining experimental characterisation of crack patterns and numerical simulationsof coupled heat and moisture transfer. First, a preliminary study was conducted, consistingof measurements of the water vapour permeability of diffusely damaged constructionmaterials.This allowed identifying the experimental and numerical requirementsof the remainder of the work, which aimed at providing measurements of fracturenetwork geometries for their explicitmodelling in heat andmoisture transfer simulations.Digital image correlation and acoustic emission monitoring were then performedduring the degradation of cementitiousmaterials, in order to obtain quantitativedata on crack pattern geometries, and to assess the possibilities for damagemonitoringat the building scale. The optical technique, along with an appropriate imageprocessing procedure, was found suitable for providing precisemeasurements of fracturenetworks. Amethodwas also proposed for the interpretation of acoustic emissionrecordings in terms of damage quantification, localisation and identification.Then, a newmodel for coupled heat andmoisturemodelling in cracked porousmediawas developed, that allows including such measurements of fracture patterns intoa finite element mesh, and simulating flow accordingly. This model was validated onthe basis of experimentalmeasurements: digital image correlationwas performed duringthe fracturing of concrete samples, in which moisture uptake was then monitoredusing X-ray radiography. A good accordance was found between experimental and numericalresults in terms of 2-dimensional moisture concentration distributions. The validated code was then used for the simulation of test cases, in order to assess the hygrothermalperformance of damagedmulti-layered building components subjected toreal climatic conditions. The consequences of fractures on themoisture accumulationin walls, on the amplitude of sorption/desorption cycles and on the thermal performance,were observed.

Afin de réduire les déchets et les émissions de CO2, la demande des constructeurs automobiles a évolué vers l'utilisation de nouveaux matériaux biosourcés permettant d'alléger les véhicules et diminuer leur consommation en carburant. Dans ce contexte, la thèse a eu pour objectif de réaliser un panneau sandwich léger et résistant renforcé par des fibres longues de lin pour des applications semistructurelles automobiles. Outre la recherche bibliographique, le travail est réparti en trois volets : la mise en œuvre, la caractérisation et la modélisation du comportement mécanique du panneau sandwich. Les peaux composites sont renforcées par un nouveau renfort « Flaxtape », qui est un voile de fibres longues de lin unidirectionnelles et ne contenant aucune filature en trame. La matrice est une résine thermodurcissable aqueuse permettant un temps de réticulation très court et une bonne processabilité. Les peaux composites et les panneaux sandwichs dérivés sont élaborés à l'aide d'un procédé de thermocompression respectant des cycles de fabrication industriels. La compréhension et l'optimisation des paramètres entrant en jeu dans leur élaboration et leur mise en œuvre (cycle de cuisson, température, séchage, densification, fraction volumique de fibres, taux de réticulation et séquence d'empilement) passent par une série de caractérisations thermomécaniques et physicochimiques. Les résultats obtenus montrent les bonnes propriétés mécaniques spécifiques du panneau sandwich à différentes températures. D'autre part, le panneau sandwich en Flaxpreg est destiné à la réalisation d'un plancher de coffre de véhicule. La modélisation numérique du comportement mécanique du panneau sandwich a permis de prédire sa réponse mécanique lorsqu'il est mis en service à différentes positions dans le coffre. Afin de simplifier la géométrie du panneau sandwich et de réduire le temps de calcul, un modèle d'homogénéisation analytique de l'âme en nid d'abeille a été utilisé pour réaliser cette étude. / To reduce waste and CO2 emissions, car manufacturers use more and more new bio-sourced materials to lighten vehicles and reduce fuel consumption. In this context, this thesis aimed at processing a lightweight sandwich panel reinforced by long flax fibers for automotive semi-structural applications.In addition to the literature state of the art, the work is divided into three parts: the material processing, characterization and modeling of the mechanical behavior of the sandwich panel. The composite skins are reinforced by a new reinforcing material "Flaxtape", which is a veil of long unidirectional flaxfibers withouth any weft spinning. The matrix is an aqueous thermosetting resin with a very short cure time and good processability. The composite skins and derived sandwich panels are processed by a thermocompression technique respecting industrial production cycles. Thermomechanical and physicochemical characterizations are used to understand and optimize the parameters involved in their development (cooking cycle, temperature, drying, densification, fiber volume fraction, degree of crosslinking and stacking sequence). Our results highlight good specific mechanical properties of the sandwich panels at different temperatures.Furthermore, the Flaxpreg sandwich panel has been used for the achievement of a vehicle compartment floor. Numerical modeling of the mechanical behavior of the sandwich panel was used to predict the sandwich panel mechanical response at different positions in the trunk. To simplify the geometry of the sandwich panel and reduce the computation time, an analytical model of the homogenized honeycomb was used in this study.

Traditionally, joints are assumed to be either pinned or fully rigid, but in reality, many behave between these two extremes giving them a semi-rigid classification. By acknowledging the semi-rigidity of nominal pin joints, steel frames can be designed as semi-continuous in which the beam bending moments are partially transmitted to the column members and the need for lateral bracing is eliminated, thus reducing material and construction costs. This thesis presents the results of numerical and theoretical studies of the behaviour of bolted endplate connections to Rectangular Hollow Section (RHS) columns using flowdrill bolts and their applications in semi-continuous frame design. Such connections exhibit significant levels of initial stiffness, strength, and deformation capacity while being more cost-effective than fully welded connections. Despite this, there is limited theoretical work carried out that allows such connections to be designed using analytical methods. In addition, there are no standardised connection design tables like that for open section columns (SCI, 1995), thereby inhibiting their adoption in practice. In this thesis, newly derived equations for initial stiffness that have a greatly improved range of validity and accuracy over existing equations are presented. Equations for bending strength of a newly derived elliptical mechanism based on yield line theory and for membrane action based on internal work principles are given. Equations for flowdrill thread stripping due to gross deformation of the RHS face are also presented thus allowing prediction of all common RHS face failure mechanisms. Equations for deformation capacity are derived thus making it possible to predict the full load-deflection behaviour of the RHS face in tension component. When combined with existing equations for bolt and endplate components, it is possible to predict the full moment-rotation behaviour of bolted endplate connections to RHS columns. Extensive parametric studies using finite element analysis (FEA) as well as validation against existing tests show that the newly derived equations can accurately predict the component-level and whole joint behaviour for a wide range of configurations. Taking advantage of the initial stiffness properties that these connections offer, a parametric study is conducted to show that connections with relatively simple detailing can offer sufficient initial stiffness and strength to enable unbraced semi-continuous design of low-rise steel frames. A hand calculation method for SLS sway in semi-continuous frames is also presented thus allowing the designer to readily carry out scheme designs without advanced software knowledge. A systematic method for the detailing of these connections for use in unbraced frame design is presented to facilitate adoption in practice.

Prior to an underground excavation a site investigation is carried out. This includes reviewing and analysing existing data, field data collected through outcrop mapping, drill core logging and geophysical investigations. These data sources are combined and used to characterise, quantify and classify the rock mass for the tunnel design process and excavation method selection. Despite the best approaches used in a site investigation, it cannot reveal the required level of detail. Such gaps in information might become significant during the actual construction stage. This can lead to; for example, over-break due to unfavourable geological conditions. Even more so, an underestimation of the rock mass properties can lead to unplanned stoppages and tunnel rehabilitation. On-the-other-hand, the excavation method itself, in this case, drill and blast, can also cause severe damage to the rock mass. This can result in over-break and reduction of the strength and quality of the remaining rock mass. Both of these attributes pose risks for the tunnel during excavation and after project delivery. Blast damage encompasses over-break and the Excavation Damage Zone (EDZ). In the latter irreversible changes occur within the remaining rock mass inside this zone, which are physically manifested as blast fractures. In this thesis, a number of methods to determine blast damage have been investigated in two ramp tunnels of the Stockholm bypass. Herein, a comparison between the most common methods for blast damage investigation employed nowadays is performed. This comparison can be used to select the most suitable methods for blast damage investigation in tunnelling, based on the environment and the available resources. In this thesis Ground Penetrating Radar, core logging (for fractures) and P-wave velocity measurements were applied to determine the extent of the blast damage. Furthermore, the study of the two tunnels in the Stockholm bypass shows a significant overestimation of the actual rock mass quality during the site investigation. In order to gain a more accurate picture of the rock mass quality, Measurement While Drilling (MWD) technology was applied. The technology was investigated for rock mass quality prediction, quantifying the extent of blast damage, as well as to investigate the potential to forecast the required rock support. MWD data was collected from both grout and blast holes. These data sets were used to determine rock quality indices e.g. Fracture Indication and Hardness Indicator calculated by the MWD parameters. The Fracture Index was then compared with the installed rock support at the measurement location. Lastly, the extent of the damage is investigated by evaluating if the MWD parameters could forecast the extent of the EDZ. The study clearly shows the capability of MWD data to predict the rock mass characteristics, e.g. fractures and other zones of weakness. This study demonstrated that there is a correlation between the Fracture Index (MWD) and the Q-value, a parameter widely used to determine the required rock support. The study also shows a correlation between the extent of the blast damage zone, MWD data, design and excavation parameters (for example tunnel cross section and charge concentration).

New experimental strategies and algorithmic approaches were devised and tested to improve the analysis of pharmaceutically relevant materials. These new methods were developed to address key bottlenecks in the design of amorphous solid dispersions for the delivery of low-solubility active pharmaceutical ingredients in the final dosage forms exhibiting high bioavailability. <br>

The subject of the thesis is study of possible applications of isoform of glutamic acid polymer (-PGA). The theoretical part is focused on the properties of this biopolymer and potential applications in various areas. Producers and mechanisms of biosynthesis are also mentioned. In the experimental part, the polymer was firstly characterised by following methods: FT-IR spectroscopy, TGA, DSC and SEC-MALS. Its isoelectric point, antimicrobial activity and solubility in various solvents were also determined. The biopolymer was also precipitated by divalent cations and its interaction with oppositely charged CTAB surfactant was studied. The main experimental study was researching the effect of -PGA on viability of Saccharomyces cerevisiae and Lactobacillus rhamnosus under stress conditions by flow cytometry. The performed stresses included ethanol exposure, high temperature and freezing stress, in which its effects were compared to conventional cryoprotectants. The cells of the mentioned microorganisms were also stressed osmotically and exposed to model gastrointestinal juices - gastric, pancreatic and bile. The protective effects of -PGA on the cells were recorded in ethanol stress on Lactobacillus rhamnosus. Its excellent cryoprotection properties were confirmed and its protective effect of gastric juice exposure on Saccharomyces cerevisiae cells was also observed. At the end of the experimental part, -PGA/alginate beads suitable for encapsulation of probiotic bacteria and -PGA/chitosan nanoparticles for encapsulation of biologically active substances.