A robust design methodology suitable for application to one-off products

Robust design is an activity of fundamental importance when designing large, complex, one-off engineering products. Work is described which is concerned with the application of the theory of design of experiments and stochastic optimization methods to explore and optimize at the concept design stage. The discussion begins with a description of state-of-the-art stochastic techniques and their application to robust design. The content then focuses on a generic methodology which is capable of manipulating design algorithms that can be used to describe a design concept. An example is presented, demonstrating the use of the system for the robust design of a catamaran with respect to seakeeping

Étude et modélisation du phénomène de croissance transitoire et de son lien avec la transition Bypass au sein des couches limites tridimensionnelles

The transition from a laminar to a turbulent flow strongly modifies the boundary layer properties. Understanding the mechanisms leading to transition is crucial to reliably predict aerodynamic performances. For boundary layers subjected to high levels of external disturbances, the natural transition due to the amplification of the least stable mode is replaced by an early transition, called Bypass transition. This is the result of non-normal mode interactions that lead to a phenomenon of transient growth of disturbances. These disturbances are known as Klebanoff modes and take the form of streamwise velocity streaks. This thesis aims at understanding this linear mechanism of transient growth and quantifying its influence on the classical modal amplification of disturbances. This is done by computing the so-called optimal perturbations, i.e. the initial disturbances that undergo maximum amplification in the boundary layer. These optimal perturbations are first determined for two-dimensional compressible boundary layers developing over curved surfaces. In particular, we show that Klebanoff modes naturally evolve towards Görtler vortices that occur over concave walls. Three-dimensional boundary layers are then considered. In such configurations, transient growth provides an initial amplitude to crossflow vortices. Finally, applying the tools developed in this thesis to new flow cases such as swept wings provides further understanding of the phenomenon of transient growth for realistic geometries.Le passage du régime laminaire au régime turbulent s’accompagne d’importantes modifications des propriétés physiques de la couche limite. La détermination précise de la transition est donc cruciale dans de nombreux cas pratiques. Lorsque la couche limite se développe dans un environnement extérieur faiblement perturbé, la transition est gouvernée par l’amplification du mode propre le moins stable. Lorsque l’intensité des perturbations extérieures augmente, des interactions multimodales entraînent une amplification transitoire des perturbations. Ce phénomène peut conduire à une transition prématurée, appelée transition Bypass. Les perturbations prennent alors la forme de stries longitudinales de vitesse appelées modes de Klebanoff. L’objectif de cette thèse est d’étudier ce mécanisme linéaire de croissance transitoire et son influence sur l’amplification modale classique des perturbations. Cela passe par la détermination des perturbations les plus amplifiées au sein de la couche limite, appelées perturbations optimales. Ces perturbations optimales sont d’abord calculées pour des couches limites bidimensionnelles et compressibles se développant sur des surfaces courbes. En particulier, on montre que les modes de Klebanoff évoluent vers les tourbillons de Görtler qui se forment sur des parois concaves. Le cas plus général de couches limites tridimensionnelles est ensuite envisagé. Pour de telles configurations, la croissance transitoire fournit une amplitude initiale aux instabilités transversales. Enfin, l’application des outils développés dans cette thèse fournit de nouveaux résultats pour des cas d’écoulements autour de géométries réalistes comme une aile en flèche

The role of reflective practice in healthcare professions: Next steps for pharmacy education and practice

Reflective practice strategies can enable healthcare practitioners to draw on previous experiences to render more effective judgment in clinical situations. The central argument presented in this commentary is that education programs and structures for continuing professional development (CPD) and revalidation of professionals sharpen their focus regarding self-assessment to identify gaps in skills and attitudes rather than merely as a means of on-going monitoring. Pharmacy undergraduate and professional education need to promote reflective practice strategies that foster self-evaluation to promote pharmacists’ readiness for practice change and advance patient care within rapidly expanding roles and scope of practice

Influence of Fining and Tartaric Stabilisation Procedures on White Wine Mannoprotein Content

Limpidity is a major quality attribute in white wine appreciation. After alcoholic fermentation and ageing,white wines are normally subjected to protein and tartaric stabilisation, followed by filtration. The impactof bentonite and gelatine fining and cold static tartaric stabilisation on the mannoprotein content of twowhite wines was studied. All treatments promoted a decrease in the content of mannoproteins. Bentonitefining largely affected the mannoproteins with the highest molecular weight, as did cold static tartaricstabilisation and gelatine fining

Chemical modeling for pH prediction of acidified musts with gypsum and tartaric acid in warm regions

Winemaking of musts acidified with up to 3 g/L of gypsum (CaSO4 2H2O) and tartaric acid, both individually and in combination, as well as a chemical modeling have been carried out to study the behaviour of these compounds as acidifiers. Prior to fermentation gypsum and tartaric acid reduce the pH by 0.12 and 0.17 pH units/g/L, respectively, but while gypsum does not increase the total acidity and reduces buffering power, tartaric acid shows the opposite behaviour. When these compounds were used in combination, the doses of tartaric acid necessary to reach a suitable pH were reduced. Calcium concentrations increase considerably in gypsum-acidified must, although they fell markedly after fermentation over time. Sulfate concentrations also increased, although with doses of 2 g/L they were lower than the maximum permitted level (2.5 g/L). Chemical modeling gave good results and the errors in pH predictions were less than 5% in almost all case

Chemical solution synthesis and ferromagnetic resonance of epitaxial thin films of yttrium iron garnet

We report the fabrication of epitaxial Y3Fe5O12 (YIG) thin films on Gd3Ga5O12 (111) using a chemical solution method. Cubic YIG is a ferrimagnetic material at room temperature, with excellent magneto-optical properties, high electrical resistivity, and a very narrow ferromagnetic resonance, which makes it particularly suitable for applications in filters and resonators at microwave frequencies. But these properties depend on the precise stoichiometry and distribution of Fe3+ ions among the octahedral/tetrahedral sites of a complex structure, which hampered the production of high-quality YIG thin films by affordable chemical methods. Here we report the chemical solution synthesis of YIG thin films, with excellent chemical, crystalline, and magnetic homogeneity. The films show a very narrow ferromagnetic resonance (long spin relaxation time), comparable to that obtained from high-vacuum physical deposition methods. These results demonstrate that chemical methods can compete to develop nanometer-thick YIG films with the quality required for spintronic devices and other high-frequency applications

Analysis of the Radiative Heat Transfer in Chains of Nanoparticles

The transfer of heat through radiation plays a crucial role in the thermalization of nanoscale objects thanks to the involvement of evanescent waves. As nanotechnology becomes a prominent area of research and development, the understanding of this phenomenon is becoming more and more crucial. In this work, we investigate the thermalization of linear chains of SiC nanospheres. To that end, we develop an analytical method that allows us to calculate the radiative heat exchange between the particles through the analysis of the normal modes of the system and their corresponding decay rates. Using this approach we analyze the time evolution of the temperature distribution of different structure

The distribution of transit durations for Kepler planet candidates and implications for their orbital eccentricities

‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyDoppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If we assume a Rayleigh eccentricity distribution for Kepler planet candidates, then we find best fits with a mean eccentricity of 0.1-0.25 for host stars with T ≤ 5100 K. We compare the transit duration distribution for different subsets of Kepler planet candidates and discuss tentative trends with planetary radius and multiplicity. High-precision spectroscopic follow-up observations for a large sample of host stars will be required to confirm which trends are real and which are the results of systematic errors in stellar radii. Finally, we identify planet candidates that must be eccentric or have a significantly underestimated stellar radius.Peer reviewedFinal Accepted Versio

On the dynamic adaptation of language models based on dialogue information

We present an approach to adapt dynamically the language models (LMs) used by a speech recognizer that is part of a spoken dialogue system. We have developed a grammar generation strategy that automatically adapts the LMs using the semantic information that the user provides (represented as dialogue concepts), together with the information regarding the intentions of the speaker (inferred by the dialogue manager, and represented as dialogue goals). We carry out the adaptation as a linear interpolation between a background LM, and one or more of the LMs associated to the dialogue elements (concepts or goals) addressed by the user. The interpolation weights between those models are automatically estimated on each dialogue turn, using measures such as the posterior probabilities of concepts and goals, estimated as part of the inference procedure to determine the actions to be carried out. We propose two approaches to handle the LMs related to concepts and goals. Whereas in the first one we estimate a LM for each one of them, in the second one we apply several clustering strategies to group together those elements that share some common properties, and estimate a LM for each cluster. Our evaluation shows how the system can estimate a dynamic model adapted to each dialogue turn, which helps to improve the performance of the speech recognition (up to a 14.82% of relative improvement), which leads to an improvement in both the language understanding and the dialogue management tasks