L'objectif de cette thèse est double : d'une part, étudier la dynamique intrinsèque dans le champ proche des jets chauds axisymétriques par simulation numérique directe, et décrire ces oscillations synchronisées sous l'angle de la théorie des modes globaux non-linéaires. D'autre part, caractériser le champ lointain aéro-acoustique généré par les oscillations synchronisées du champ proche, également par simulation numérique directe, et identifier la nature physique des sources aéro-acoustiques dans le jet. Ainsi il est établi que les oscillations synchronisées intrinsèques que l'on observe dans les simulations possèdent toutes les caractéristiques d'un mode global non-linéaire, régi par un front stationnaire situé au bord amont d'un milieu absolument instable. Une analyse d'instabilité linéaire révèle qu'un jet suffisament chaud devient absolument instable près de la buse, grâce à l'effet déstabilisant du couple barocline. L'apparition des oscillations auto-entretenues ainsi que leur fréquence, observées numériquement, suivent précisement les prédictions déduites des critères théoriques. Les résultats numériques sont en bon accord avec les expériences tirées de la littérature. Le mode global d'un jet chaud émet un champ sonore dipolaire; une analyse de l'équation de Lighthill révèle que ce rayonnement est dû aux fluctuations d'entropie, à la différence d'un jet isotherme forcé, pour lequel les sources quadripolaires liées au tenseur de Reynolds sont dominantes.

Cette thèse vise à fournir et éprouver de nouveaux outils théoriques, numériques et informatiques de calculs de modes non linéaires pour des structures à non linéarité géométrique et discrétisées par éléments finis. La surface invariane de l'espace des phases caractérisant le mode non linéaire est décrite à partir d'une famille d'orbites périodiques solutions des équations du mouvement. Chaque orbite périodique est discrétisée en temps (schéma de Newmark et de Simo) et formulée à l'aide d'un système d'équation global contenant toutes les inconnues à tous les pas de temps, c'est la méthode simultanée, par opposition à la méthode de tir classique. Les familles d'orbites solutions du système global sont obtenues par la méthode de continuation MAN (Méthode Asymptotique Numérique). Des variations autour de la MAN sont aussi abordées. Il s'agit d'apports liés au contrôle de la continuation au passage des points de bifurcations à l'aide d'une perturbation ajoutée au système d'équation non linéaire. On présente un outil-logiciel, MANLAB, permettant la continuation interactive de diagrammes de bifurcation complexes, qui est appliquée à la continuation de famille d'orbites périodiques.

L'objectif de cette thèse est de mettre en évidence l'influence des modes de financement sur les pratiques comptables, entre 1890 et 1939, en France. Cette période a été choisie en raison de l'absence de normalisation comptable, offrant la plus grande liberté d'action aux industriels dans leurs pratiques comptables. Par ailleurs, ces années se caractérisent par un accès potentiel à différents moyens de financement externe. Deux études de cas ont été menées à partir des rapports annuels d'Assemblée Générale des sociétés Schneider et L'Air Liquide. La première se distingue par un recours important à l'autofinancement. Cette structure de financement est favorisée par l'application d'un modèle comptable statique, inchangé entre 1890 et 1939. En revanche, L'Air Liquide se caractérise par un recours récurrent à des augmentations de capital pour financer sa croissance. Les pratiques comptables de cette société s'inscrivent alors dans une conception dynamique de la comptabilité. A travers ces études de cas, la thèse montre l'existence d'une relation étroite entre les modes de financement et les pratiques comptables. L'explication de cette influence nécessite néanmoins la prise en compte de facteurs tels que la structure de l'actionnariat, le secteur d'activité, ou encore le profil des dirigeants.

This thesis is concerned with the derivation of bioprocess models intended for engineering purposes. In contrast with other techniques, the methodology used to derive a macroscopic model is based on available intracellular information. This information is extracted from the metabolic network describing the intracellular metabolism. The aspects of metabolic regulation are modeled by representing the metabolism of cultured cells with several metabolic networks. Here we present a systematic methodology for deriving macroscopic models when such metabolic networks are known. A separate model is derived for each “phase” of the culture. Each of these models relies upon a set of macroscopic bioreactions that resumes the information contained in the corresponding metabolic network. Such a set of macroscopic bioreactions is obtained by translating the set of Elementary Flux Modes which are well-known tools in the System Biology community. The Elementary Flux Modes are described in the theory of Convex Analysis. They represent pathways across metabolic networks. Once the set of Elementary Flux Modes is computed and translated into macroscopic bioreactions, a general model could be obtained for the type of culture under investigation. However, depending on the size and the complexity of the metabolic network, such a model could contain hundreds, and even thousands, of bioreactions. Since the reaction kinetics of such bioreactions are parametrized with at least one parameter that needs to be identified, the reduction of the general model to a more manageable size is desirable. Convex Analysis provides further results that allow for the selection of a macroscopic bioreaction subset. This selection is based on the data collected from the available experiments. The selected bioreactions then allow for the construction of a model for the experiments at hand.

We report on a project with Polaroid Corporation in which we developed a supply chain model to provide decision support for planning production and transportation. Production occurs in Asia to serve world-wide demand. Production planners must determine both the production quantities as well as whether to ship by sea or by air. We develop a model to optimize a static version of this problem and then show how to use this static model in a dynamic setting. We test the model with data from Polaroid and show its effectiveness. / Singapore-MIT Alliance (SMA)

The technique of single particle Total Internal Reflection Microscopy (TIRM) has been used to study the scattering intensity from levitated microspheres. TIRM can be used to monitor the separation between microscopic spheres immersed in liquid (water in our case) and a surface with nm resolution. In the technique, microspheres scatter light when the evanescent waves are incident upon them. The intensity of the scattered light is directly related to the height above the surface and allows determination of the height. From the separation distance histograms, the interaction between the microsphere and interface may be characterized with a force resolution in the range of 0.01 picoNewtons. Such a system can be applied to the measurement of biomolecular interactions biomolecules attached to the microsphere and the surface. The intensity and scattering pattern of this light has been modeled using a modified Mie theory which accounts for the evanescent nature of the incident light. Diffusing Colloidal Probe Microscopy (DCPM) is an extension of the TIRM technique that simultaneously monitors multiple microsphere probes. The use of multiple probes introduces the issue of probe polydispersity. When measured at the surface, a variation in scattered light intensity of nearly one order of magnitude has been observed from a purchased microsphere sample. Thus the polydisperse collection of microspheres adds significant complexity to the scattered light signal. It is hypothesized that the dependence of the total scattered light intensity on microsphere size accounts for the scattered intensity distribution in a polydisperse microsphere sample. Understanding this variation in the scattered light with microsphere size will allow improved characterization of the microsphere/surface separation. Additionally, larger microspheres have the ability to resonantly confine light and produce spectrally narrow Whispering Gallery Modes (WGMs). It is hypothesized that WGMs may be excited in microspheres with the DCPM system. These modes may be used as a refractometric biosensor with high sensitivity to local refractive index changes on the surface of the microsphere. This research involves modeling scattered intensity distributions for polydispersed collections of microspheres based on modified Mie theory. The theoretical results are compared to experimentally obtained results and found to qualitatively explain the scattered light intensity distribution in a multiple probe DCPM system. This is an important result suggesting that microsphere size variation plays a major role in determining the distribution of scattered intensity in multiple microsphere probe systems. This work also suggests that it may be possible to excite such WGMs in a DCPM system. The introduction of WGMs would enable refractometric biosensing in such evanescent mode systems.

The technique of single particle Total Internal Reflection Microscopy (TIRM) has been used to study the scattering intensity from levitated microspheres. TIRM can be used to monitor the separation between microscopic spheres immersed in liquid (water in our case) and a surface with nm resolution. In the technique, microspheres scatter light when the evanescent waves are incident upon them. The intensity of the scattered light is directly related to the height above the surface and allows determination of the height. From the separation distance histograms, the interaction between the microsphere and interface may be characterized with a force resolution in the range of 0.01 picoNewtons. Such a system can be applied to the measurement of biomolecular interactions biomolecules attached to the microsphere and the surface. The intensity and scattering pattern of this light has been modeled using a modified Mie theory which accounts for the evanescent nature of the incident light. Diffusing Colloidal Probe Microscopy (DCPM) is an extension of the TIRM technique that simultaneously monitors multiple microsphere probes. The use of multiple probes introduces the issue of probe polydispersity. When measured at the surface, a variation in scattered light intensity of nearly one order of magnitude has been observed from a purchased microsphere sample. Thus the polydisperse collection of microspheres adds significant complexity to the scattered light signal. It is hypothesized that the dependence of the total scattered light intensity on microsphere size accounts for the scattered intensity distribution in a polydisperse microsphere sample. Understanding this variation in the scattered light with microsphere size will allow improved characterization of the microsphere/surface separation. Additionally, larger microspheres have the ability to resonantly confine light and produce spectrally narrow Whispering Gallery Modes (WGMs). It is hypothesized that WGMs may be excited in microspheres with the DCPM system. These modes may be used as a refractometric biosensor with high sensitivity to local refractive index changes on the surface of the microsphere. This research involves modeling scattered intensity distributions for polydispersed collections of microspheres based on modified Mie theory. The theoretical results are compared to experimentally obtained results and found to qualitatively explain the scattered light intensity distribution in a multiple probe DCPM system. This is an important result suggesting that microsphere size variation plays a major role in determining the distribution of scattered intensity in multiple microsphere probe systems. This work also suggests that it may be possible to excite such WGMs in a DCPM system. The introduction of WGMs would enable refractometric biosensing in such evanescent mode systems.

The overall objective is to improve the one-dimensional numerical prediction of the fine and non-cohesive bed material load in alluvial rivers, especially during high intensity episodes during which sediment beds are strongly remobilized. For this reason, we attempt to reduce the major inaccuracy sources coming from the alluvial resistance and bed material load relations needed to close the mathematical system. Through a shared parameter called the control factor m, the interactions occurring in alluvial rivers are incorporated more deeply into the mathematical model and more particularly into the closure laws: bed material load (SVRD, Suction-Vortex Resuspension Dynamics) and the energy slope (Verbanck et al. 2007). The control factor m is assumedly related to the Rossiter resonance modes of the separated flow downstream the bed form crest. To further improve the representation of the flow-sediment-morphology interactions, a fully coupled model approach has been naturally chosen. In this work the terminology fully coupled means that the three equations forming the system are solved synchronously and that the terms often neglected by more traditional decoupled models are kept. The feasibility of the new closure methodology has been drawn up by reproducing numerically the silt-flushing experiment conducted by the Yellow River Conservancy Commission (Y.R.C.C.) in the Lower Yellow River (LYR) in Northern China. The objective of the silt flushing experiment is to reverse the aggradation trend of the Lower Yellow River which, in the last decades, has become a perched river. The numerical simulation specifically reproduces the silt-flush effects in a reach of LYR located in the meandering part of the river. This reach (around 100 km) is delimited by Aishan and Luokou hydrometric stations. Since the SVRD formulation has been developed from flume observations, the law has first been confronted to river datasets. The confrontation has revealed that the SVRD law becomes less suitable for fine sediment fluxes (ratio of water depth over median particle size > 5000). Therefore, a modified equation SVRD-2 has been built to enlarge the validity range. The suitability of the SVRD-2 equation to predict fine sediment fluxes has been tested on data available from several hydrometric stations located in the meandering reach of the LYR: historical observations and measures collected during the flushes. The SVRD-2 has also been compared with relations specifically calibrated for this configuration. The comparison has pointed out that the performance of the two formulas is similar, which is encouraging for the SVRD-2 approach as it has not been calibrated on those data. The closed equation system has been written on its quasi-linear form and is solved by a Finite Volume Method combined with a linearized Riemann algorithm. The numerical model has been checked up on two test cases: deposition upstream of a dam and the aggradation experiment conducted by Soni 1975. As it is not yet possible to predict dynamically the value of the control factor m, a possible solution would be to extract its value from the measured data at the inlet cross section. Unfortunately, the necessary data are not measured locally. Moreover, a uniform value of the control factor m may not suffice to reproduce the flow along the whole reach. Therefore, it has been proposed to work temporarily in the reverse way. From the comparison between the numerical results and the experimental data, a time evolution of the control factor m has effectively been extracted and it has been shown that it varies along the reach. At Aishan, the evolution of the control factor m corresponds to the evolution expected from the data analysis previously conducted on other data sets: the value of the control factor m decreases during the flush as it tries to reach the optimal value m=1. The time evolution at Luokou behaves differently to the one at Aishan, but remains in agreement with m evolution patterns observed historically for the river section flowing round Jinan City walls. For Luokou, the highlighted differences may come from three dimensional effects coming from the meander bend upstream the station. Generally, the results obtained for the hydraulics, the sediment transport and bed adaptation are encouraging but still need improvements and additional feeding from the experimental data. The results for the concentration and therefore the bed elevation are very sensitive to the value of the control factor m as it influences most of the terms of the bed material load equation (SVRD-2). The major remaining difficulties are, firstly, to deal with the rapid transients for which the model is less suitable and, secondly, to improve the prediction of the value of control factor m. Before paying more attention into the transients, enhancements concerning the flow along the reach (initial condition and discharge rates during the first days of the flush) must be conducted in priority. Indeed as the prediction of the bed or the cross section evolutions depend directly on the quality of the prediction of the sediment concentration and the hydraulics, one should first improve these aspects. To perform this study, more information about the water levels or sediment concentrations is necessary at some intermediate stations. One solution is to lengthen the studied reach, upstream to Sunkou and downstream to Lijin, totaling a river length of 456 Km. A more entire signal of the energy slopes and the associated bed configurations at different stations would enlighten how the control factor m evolves along the reach during the silt-flush events.

Axicons are optical elements that produce Bessel beams,i.e., long and narrow focal lines along the optical axis. Thenarrow focus makes them useful ine.g. alignment, harmonicgeneration, and atom trapping, and they are also used toincrease the longitudinal range of applications such astriangulation, light sectioning, and optical coherencetomography. In this thesis, axicons are designed andcharacterized for different kinds of illumination, using thestationary-phase and the communication-modes methods. The inverse problem of axicon design for partially coherentlight is addressed. A design relation, applicable toSchell-model sources, is derived from the Fresnel diffractionintegral, simplified by the method of stationary phase. Thisapproach both clarifies the old design method for coherentlight, which was derived using energy conservation in raybundles, and extends it to the domain of partial coherence. Thedesign rule applies to light from such multimode emitters aslight-emitting diodes, excimer lasers and some laser diodes,which can be represented as Gaussian Schell-model sources. Characterization of axicons in coherent, obliqueillumination is performed using the method of stationary phase.It is shown that in inclined illumination the focal shapechanges from the narrow Bessel distribution to a broadasteroid-shaped focus. It is proven that an axicon ofelliptical shape will compensate for this deformation. Theseresults, which are all confirmed both numerically andexperimentally, open possibilities for using axicons inscanning optical systems to increase resolution and depthrange. Axicons are normally manufactured as refractive cones or ascircular diffractive gratings. They can also be constructedfrom ordinary spherical surfaces, using the sphericalaberration to create the long focal line. In this dissertation,a simple lens axicon consisting of a cemented doublet isdesigned, manufactured, and tested. The advantage of the lensaxicon is that it is easily manufactured. The longitudinal resolution of the axicon varies. The methodof communication modes, earlier used for analysis ofinformation content for e.g. line or square apertures, isapplied to the axicon geometry and yields an expression for thelongitudinal resolution. The method, which is based on abi-orthogonal expansion of the Green function in the Fresneldiffraction integral, also gives the number of degrees offreedom, or the number of information channels available, forthe axicon geometry. Keywords:axicons, diffractive optics, coherence,asymptotic methods, communication modes, information content,inverse problems

This study aims to investigate elementary models of social relations in Turkish cultural context and to link these models with horizontal and vertical individualism and collectivism and personal value priorities. Fiske (1992) suggested that four elementary relationship models: communal sharing, authority ranking, equality matching, and market pricing motivate, organize, generate, coordinate, and evaluate almost all social relations. First, the Modes of Relationship Questionnaire (MORQ) asessing the four relational models was adopted to Turkish. Second, systematical associations of relational models with horizontal and vertical individualism and collectivism and personal value priorities were examined. It was expected that horizontal cultural dimensions would predict equality matching and vertical dimensions would predict authority ranking, individualism would be linked to market pricing and collectivism would be linked to communal sharing. For personal value priorities, self-trancendence values would be associatedwith communal sharing, self-enhancement with authority ranking and market pricing, and conservation with authority ranking. Participants (N = 214) completed the MORQ, the Individualism and Collectivism Scale (INDCOL), and the Portrait Values Questionnaire (PVQ). The four factor-structure of the relational models was supported in comfirmatory factor analyses. The hypothesized associations between relaitonal models, cultural orientations, and personal priorities were mostly supported. The results indicated that collectivism predicted communal sharing, vertical dimensions predicted authority ranking, horizontal collectivism predicted equality matching, and vertical individualism predicted market pricing. It was also found that self-trancendence predicted communal sharing and equality matching, self-enhancement predicted authority ranking and market pricing, and conservation predicted authority ranking.Theoretical, methodological, and practical implications of the findings were discussed considering previous work and cultural context.