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No / The surface energetic parameters of carbamazepine and paracetamol have been studied using inverse gas chromatography modified to produce dry and ambient conditions within the column. The values of the dispersive component of the surface free energy (¿DS) do not change significantly at the increased relative humidity. In contrast the specific component of the free energy of adsorption (-¿GSPA) as measured by polar probes, can either remain constant or decrease by up to 10%, depending on the material and the probe. This indicates that an increase in the relative humidity causes a decrease in the surface energetics of the powder surface. It is proposed that where the water molecules are adsorbing to the same sites as the polar probes, the interaction of these probes with the surface is decreased. To identify these sites, the preferential interaction of each probe, including water, with the drug molecule has been modelled.

Aim of this study was to describe capillary water and vapor transport in shallow subsurface of Hrubá Skála sandstone in the Bohemian Paradise. I have quantified permeability of Hrubá Skála sandstone for water vapor using "wet cup" method and also capillary water absorption of sandstone drill cores. I have found out general rules of evaporation and rate of evaporation from several sandstone outcrops in real microclimate. Important part of my work was to determine whether surface crust plays some role in studied parameters. Based on my results, permeability of different types of sandstones for water vapor does not vary significantly and surface crust has no effect on rate of water vapor diffusion. Rate of capillary water absorption is reduced by surface crust. Hrubá Skála sandstone is classified as medium or highly absorbing material. I have proved that evaporation from porous medium can be approximated by exponential function. Rate of evaporation is strongly controlled by climatic conditions, especially by relative humidity. Powered by TCPDF (www.tcpdf.org)

L'objectif général de cette thèse de doctorat est de caractériser les propriétés de membranes PFSA de type Nafion N115 et Nafion NRE212 en termes de sorption d'eau, de propriétés de transport et de propriétés mécaniques, sur une large gamme de conditions expérimentales. Nous avons réalisé de très nombreuses mesures afin de comparer les résultats avec les données de la littérature, souvent dispersées. Des protocoles simples et reproductibles nous ont permis de mesurer les propriétés des membranes et d'étudier l'influence de certains paramètres sur leur variation. Les échantillons ont par exemple été séchés à différentes températures et nous avons étudié l'effet de ce prétraitement thermique sur la capacité de sorption, les propriétés de transport et les propriétés mécaniques. Les membranes Nafion ont également été exposées à une température modérée (60°C - 80°C) et à une humidité relative constante (RH = 0.3 à 0.95) pendant plusieurs semaines, conditions à l'origine d'un phénomène dit de "vieillissement hygrothermique" qui affecte leur capacité de sorption et leur conductivité protonique. De tels effets ont été observés mais ils se sont révélés réversibles et sans conséquences notables en terme de performances une fois les membranes utilisées en pile à combustible. Nos résultats peuvent être utilisés dans des études impliquant le transport et la gestion de l'eau dans les piles à combustible ainsi que leur durabilité, en particulier pour de la simulation numérique ou de la modélisation. Plus fondamentalement, ils peuvent aider à comprendre la thermodynamique de sorption et les phénomènes de transport dans les membranes PFSA / The overall aim of this PhD thesis was to characterize the properties of commercial Nafion N115 and Nafion NRE212 membranes in term of water sorption, transport, and mechanical properties over a wide range of experimental conditions. Because of the high dispersion of the data in the literature, our primary objective was to gather a comprehensive set of experimental measurements and to compare them with published results. Simple and reproducible protocols allowed us to measure the membrane properties over a wide range of experimental conditions and to study the influence of certain parameters on their evolution. For example, the samples were heat-treated at different temperatures and the effect of thermal history on water sorption, transport and mechanical properties was investigated. Nafion membranes were also exposed to moderate temperature (60°C - 80°C) and constant relative humidity (RH = 0.3 to 0.95) for long periods of time, which is known to cause a so-called ?hygrothermal aging? resulting in a decrease in their sorption capacity and proton conductivity. Such effects were observed but they appeared to be reversible and without noticeable consequences in term of fuel cell performance. Our experimental results can be used in studies involving water transport, water management and durability of fuel cells, especially for numerical simulation or modelling. More fundamentally, they can help understanding the thermodynamics of sorption and transport phenomena in PFSA membranes

La terre compactée est considérée comme un mélange granulaire dans lequel l'argile joue un rôle de liant mais cette dernière exhibe une forte interaction avec l'eau. Pendant la durée de vie en service, la terre compactée est soumise aux changements de l’humidité relative. En raison de ces changements des conditions ambiantes perpétuels, la teneur en eau dans la terre varie, impactant leur performance mécanique. Le présent travail a ainsi pour but d’étudier l’impact de l’humidité relative et de la teneur d'argile sur le comportement mécanique de la terre compactée. Il se réalisera au travers d’études expérimentales et d'une modélisation constitutive. Dans la première partie de cette thèse, quatre terres régionales de provenances et de teneurs d'argile différentes sont identifiées. Une étude comparative a été réalisée entre le double compactage statique et le compactage dynamique. En parallèle, trois types d'essais spécifiques : essais de succion par la méthode de papier-filtre, essais de retrait et essais d'absorption d'eau, ont été menés pour donner des indications préliminaires quant aux effets d'interaction entre l'eau et l'argile. Dans la deuxième partie, l’impact de l’humidité relative et de la teneur d'argile sur le comportement de cisaillement a été étudié, prenant en compte des cycles de chargement-déchargement. En adoptant une définition particulière de la contrainte effective de Bishop, il a également été observé que les états de rupture dans le plan (p'-q) pour tous les échantillons sont alignés approximativement à une ligne droite unique passant par l'origine, quelque soit la succion et la pression de confinement. Sur la base des résultats expérimentaux, un nouveau modèle constitutif a été développé pour la simulation du comportement mécanique de la terre compactée. Ce nouveau modèle a ainsi été formulé dans la cadre de la mécanique de l'endommagement des milieux continus et de la théorie de Bounding Surface Plasticity. / Compacted earth is regarded as a granular mixture in which clay plays a role of binder but it also exhibits an important interaction with water. During their service life, compacted earth can be subject to large changes in relative humidity. Those perpetual changes of environmental conditions induce continuous changes of water content of the earth that impact significantly its mechanical performances. The present work aimes at studying the mechanical behavior of compacted earth with respect to relative humidity and clay content. It involves an extensive experimental study and a constitutive modelling. In the first part of this thesis, four kinds of local earth are identified with different clay contents. A comparison of compaction method was then conducted between a double static compaction and dynamic compaction. Three types of specific tests: suction test by filter paper method, shrinkage test and sorption-desorption test were carried out, thereby providing a preliminary insight on the interaction effects between clay and water. In the second part, the impact of clay and moisture contents on the shear behavior of compacted earth was investigated taking into account loading-unloading cycles. Adopting a particular definition of Bishop's effective stress, failure states of all samples were observed to lie approximately on a unique failure line crossing the origin in the (p'-q) plane regardless of matric suction and confining pressure. Finally, based on the above experimental results, a new constitutive model was proposed, based on the theories of Bounding Surface Plasticity and continuum damage mechanics, aiming to simulate mechanical behaviour of compacted earth.

Das Ziel der experimentellen Arbeit war die Untersuchung der Einflussfaktoren auf den Ertrag, die Saatgutqualität unter verschiedenen Lagerungsbedingungen sowie die Effizienz der Expression vonRamtillkraut (Guizotia abbysinica Cass.). In Feldversuchen wurden folgende Varianten untersucht, Sorten ‚Fogera‘ und ‚Kuyu‘, Saatgutaufwand von 5, 10, 15 kg ha-1, ein Stickstoffaufwand von 13, 23 und 33 kg ha-1, sowie eine differenzierte Wasserversorgung an zwei Standorten (Adet und Koga). In Adet wurde der höchste Saatgut Ertrag mit 1.384,60 kg ha-1 ermittelt, Erträgen in Koga (ohne Bewässerung) mit 1.064,72 kg ha-1 und 967,00 kg ha-1 (mit Bewässerung). Der höchste Ölgehalt wurde im Saatgut aus Koga (ohne Bewässerung) mit 41,54% ermittelt, gefolgt von Koga (mit Bewässerung) 39,59% und Adet mit 38,67%. Signifikante Unterschiede wurden zwischen den N-Aufwandmengen in Koga mit Bewässerung und Saatgutmengen in Adet ermittelt. Die Unterschiede bei den Fettsäuregehalten in Adet waren nicht signifikant. Der Alpha-Tocopherol Gehalt betrug 80 mg pro 100 g bei hoher Saatdichte und hoher N-Düngung. Hinsichtlich des Verfahrens des Ölpressens, wurde ein signifikanter Unterschied zwischen Effizienz und Temperatur ermittelt. Die Dauer der Konditionierung und die Vorschubgeschwindigkeit sind negative korreliert gleichfalls mit der Effizienz der Expression. Die Temperaturen von 70°C und 80°C zeigten keinen signifikanten Einfluss auf die Ölausbeute, dagegen war der der Einfluss von 90°C statistisch signifikant. / The aim of this study was to investigate factors influencing seed yield, postharvest handling, and the oil expression efficiency for nigerseed (Guizotia abbysinica Cass.). Based on field study on two varieties, two locations, three seed rates and three fertilizer rates the highest mean nigerseed yield was 1384.6 kg ha-1 at Adet location (rain fed) followed by location Koga (rain) with 1064.7 kg ha-1 and Koga (irrigation) with 967.0 kg ha-1 showing significant difference. The oil content by location was 41.54% for Koga (rain) followed by 39.59 and 38.67% for Koga (irrigation) and Adet (rain) respectively showing significant difference whereas the Ash content showed a reverse trend of oil content. Fatty acid composition did not show significant difference in any treatment. Significant mean alpha-tocopherol of 80 mg/100 g (70 to 89 mg/100 g) was attained for increasing seed and nitrogen rates. Based on two temperatures and seven relative humidities model evaluation and monolayer moisture content estimation, Guggenheim-Anderson-de Boer (GAB) models was found to best suit both varieties as compared to Brunauer-Emmet-Teller (BET), and modified Chung &Pfost. For oil expression efficiency, 90ºC seed conditioning showed significant effect compared to 80 and 70ºC however conditioning times and feed rates did not differ significantly.

Studien handlade om att belysa hur UAV:s kan komma till nytta i meteorologisk forskning och att ta reda på hur bra drönare är på att mäta meteorologiska storheter. Drönare, som också kallas UAV:s (Unmanned Aerial Vehicle) är mindre obemmanade luftfartyg som kan flyga autonomt eller fjärrstyras. Idag används drönare alltmer i meteorologi vilket beror mycket på den tekniska utvecklingen. Exempel på meteorologiska applikationer är mätning av vindhastighet och koncentrationen av koldioxid i luften som kan användas för att studera de lägsta atmosfäriska skikten. Storheter som mättes i detta projekt var vindhastighet, vindriktning, temperatur och relativ fuktighet på olika höjder. Mätningarna gjordes två gånger i en mätstation i Marsta, som ligger utanför Uppsala. Efteråt jämfördes datan från drönaren med data från en instrumenterad mast vid väderstationen. Resultaten visade att drönarens vindprofiler stämde ganska väl överens med mastens vindprofiler och den logaritmiska vindlagen. Under den första fältmätningen uppskattade drönaren att vindhastigheten var 8.13 ± 1.33 m/s vid hovring på tio meters höjd medan masten angav 8.41 ± 0.958 m/s. Drönarens mätvärden för vindriktningen var ibland bra och ibland mindre bra. Mätvärdena för temperaturen och den relativa fuktigheten avvek med upp mot 1 ◦C respektive 10 procentenheter. / The aim of this report was to study how UAV:s can be applied in meteorological research and find out how good drones are at measuring meteorological parameters. A drone, also known as an UAV (Unmanned Aerial Vehicle) is a smaller unmanned aircraft that can fly autonomously or under remote control. Today, drones are used more frequently in meteorology, mostly due to the recent technological development. Examples of meteorological applications include measurements of wind speed and the amount of carbon dioxide in the air which can be used to analyze the lower parts of the atmosphere. In this project, the wind speed and its direction, the temperature and the relative humidity were measured at different heights. The measurements took place twice in Marsta which is a field station outside Uppsala. Then, the data from the drone was compared to the data from a weather tower at the instrumented station. The results showed that the drone’s wind profiles were relatively similar to the profiles according to the tower and the logarithmic wind profiles. For instance, during the first flight the drone estimated the wind speed to be 8.13 ± 1.33 m/s while hovering ten metres above the ground. The tower measured 8.41 ± 0.958 m/s at the same height. The drone’s estimations of the wind direction were sometimes accurate and sometimes not accurate. The temperature and relative humidity however was different by 1 ◦C and ten percentage units respectively.

L’instrumentation de plus en plus poussée des systèmes mécaniques (aéronautique, automobile,…) impose une utilisation croissante des connecteurs électriques. Cependant, leur environnement de fonctionnement (sollicitations chimiques et vibratoires) peut entrainer une dégradation plus ou moins sévère des contacts électriques limitant ainsi le passage du courant. Pour limiter cette dégradation et assurer la stabilité des connexions, des revêtements d’or sont couramment appliqués au niveau des contacts. Cependant, la conjecture économique et le coût très élevé de l’or nécessite de trouver une alternative moins chère. Parmi les métaux conducteurs, l’argent est aujourd’hui le meilleur candidat. L’objectif de cette thèse est donc d’étudier la réponse électrique et l’endommagement de dépôts argent soumis à des sollicitations de fretting. Pour cela, ces travaux de recherche ont été abordés selon trois axes. Le premier axe a permis une étude complète d’un contact homogène argent/argent afin d’identifier les mécanismes de dégradation responsables de la rupture électrique aussi bien en fretting qu’en glissement alterné. Il a aussi été possible, par une approche énergétique, de mettre en place un modèle prédictif permettant d’extrapoler les durées de vie du contact selon différents paramètres de chargement. Une étude complémentaire a également montré l’impact d’une atmosphère corrosive à base de soufre sur les contacts électriques en argent. Le second axe a permis, quant à lui, d’étudier le comportement tribologique et électrique de nouveaux matériaux à base d’argent développés dans le but de remplacer les dépôts dorés. L’analyse de ces contacts homogènes a permis de mettre en évidence les mécanismes de dégradation et les comportements mécaniques des contacts soumis à des environnements humides. Dans le dernier axe, une étude a été menée sur ces mêmes matériaux à base d’argent mais en configuration hétérogène contre un dépôt d’or afin d’identifier le comportement tribologique et électrique de ces contacts quand ils sont composés par des matériaux avec des propriétés similaires ou opposées. / Advanced instrumentation in mechanical systems (aeronautical, automobile etc…) goes hand in hand with an ever increased use of electrical connectors. However, the unfavorable operating environment (chemical attack and vibrational loads) causes more or less severe degradation of electrical contacts, which in turn perturbs their electrical conductivity. Gold plating is usually applied in electrical contacts in order to limit damage and to ensure connector stability. However, economic constraints and the high cost of gold require cheaper alternatives. Amongst conductive metals, silver is the best candidate. Hence, the purpose of this PhD project is to investigate the electrical response and the degradation of silver coatings when subjected to fretting loadings. The study is divided into three main research axes. The first axis consists in realizing a complete study of a homogeneous silver/silver contact in order to identify the degradation mechanisms that are responsible for the electrical failure, both in fretting loadings and reciprocating sliding. It was possible to formalize a predictive model, using an energy density approach, allowing to extrapolate the lifetime of the contact as a function of various loading parameters. A complementary study also showed the impact of a corrosive sulfur atmosphere on these electric contacts. As part of the second research axis, an investigation of the tribological and electrical behavior of novel silver-based materials, solely synthesized as a gold replacement, was performed. The analysis of these homogeneous contacts allowed to explain the degradation mechanism and the mechanical behavior of these contacts when subjected to a wet environment. In the last research axis a study was led on the same silver-based materials but in a heterogenous configuration against a gold coating in order to identify the tribological and electrical behavior of these contacts when composed by materials with similar or opposite properties.

Rain forest canopies are renowned for their very high biodiversity and the critical role they play in key ecological processes and their influence on global climate. Despite that New Zealand supports one of the most diverse and extensive epiphyte flora of any temperate forest system, few studies have investigated epiphyte communities and their invertebrate fauna along with factors that influence their distribution and composition. This thesis represents the first comprehensive study of entire epiphyte communities and their resident invertebrate fauna in the canopy of New Zealand’s indigenous forests. The aim of this study was to determine spatial patterns of epiphyte and invertebrate species richness, abundance and community composition in relation to abiotic variables, and in particular, the responses of these communities to elevated temperature and rainfall. This study was carried out in coastal lowland podocarp-broadleaved forests at two sites on the West Coast of the South Island of New Zealand. Samples from 120 mat-forming epiphyte assemblages located on inner canopy branches of 40 northern rata (Metrosideros robusta) trees were studied to characterise the component flora and fauna. Additionally, biomass, branch and tree characteristics and community responses to treatments designed to elevate temperature and rainfall to simulate predicted climate change were measured. This investigation revealed astonishing diversity and functional complexity of epiphyte and invertebrate life in this ecosystem. The 30.6 kg (dry weight) of epiphyte material collected contained a total of 567 species, 170 epiphyte and 397 invertebrate (excluding immature specimens and mites) species, including at least 10 species new to science and many undescribed species Epiphyte communities were found to be dominated by non-vascular plants (80 % of the total species richness), particularly liverworts and invertebrate communities were dominated with respect to abundance (~ 80 % of the total individuals) by Acari, Collembola and Hymenoptera (primarily ants) and functionally by scavengers and ants. Epiphyte and invertebrate communities were highly variable with respect to spatial patterning of species richness, abundance and composition across sites, among trees within sites and among branches within trees. Overall, a highly significant proportion, > 75 %, of the variance could be attributed to differences at the branch level, but these differences could not be explained by the environmental factors measured. There were no consistent relationships between the spatial pattern of epiphytes and invertebrates, or between vascular and non-vascular plants. However, there were significant positive correlations between epiphyte biomass and invertebrate species richness (r = 0.472; p < 0.0001) and abundance (r = -0.395; p < 0.0001), as well as non-living epiphyte biomass and scavenger species richness (r = 0.4; p < 0.0001). Microclimatic measurements taken on epiphyte mats were also highly variable with respect to temperature and relative humidity at similar physical locations within the same tree as well as across trees within sites. There was also considerable variation in the intensity and frequency of climatic extremes, although potentially harmful climatic conditions were experienced by all the epiphyte mats for which weather variables were measured. Negative correlations existed between both epiphyte and invertebrate community composition and increased temperatures expressed as cumulative degree days above 5˚C. However, variability was such that there was no direct evidence that increased temperature and rainfall treatments had an effect on invertebrate species richness, abundance or diversity. Northern rata host trees harbour an astonishingly diverse and complex canopy flora and fauna that is characterised by high spatial variability. Such variability highlights that to determine species distribution and community dynamics in canopy habitats in response to disturbance caused either by climate change or invasive species the structure of entire communities at different taxonomic and spatial scales, along with their responses to microclimatic factors, need to be studied. If such complexities are not taken into account, inappropriate interpretation may result in poor decisions concerning the conservation status, vulnerability and subsequent management of such unique ecosystems.