Le vieillissement des lignes de transport d’énergie électrique est une problématique majeure des réseaux. D’ailleurs, des problèmes se posent au plan de l’évaluation de l’état des conducteurs qui, soumis aux vibrations éoliennes, sont vulnérables à l’endommagement en fatigue. Surtout présent aux pinces de suspension, ce phénomène est encore difficile à quantifier, notamment quant à la prédiction de la durée de vie résiduelle des conducteurs. D’autre part, avec le besoin croissant d’optimiser l’exploitation du réseau tout en maintenant sa fiabilité, une estimation précise de l’état d’endommagement des conducteurs est primordiale. Pour cela, une caractérisation des sollicitations à l’échelle des brins est d’abord requise. L’objectif principal de cette thèse vise donc le développement d’une stratégie de modélisation et d’analyse des conducteurs sollicités en vibrations éoliennes permettant une évaluation précise des conditions de chargement locales à l’échelle des brins, tout en tenant compte de l’effet de la géométrie des pinces de suspension. Une stratégie de modélisation 3D des solides toronnés est d’abord développée avec la méthode des éléments finis selon une discrétisation individuelle des brins par éléments poutres, capable de traiter toutes les interactions inter-filaires en frottement. Cette modélisation traduit efficacement la cinématique des torons tout en donnant accès aux charges locales. Son caractère général lui permet aussi d’être appliquée à tout problème impliquant des torons. Appliquée à l’étude des conducteurs sous l’effet des vibrations éoliennes, la stratégie conduit à une description précise de leur comportement tant au plan global en flexion que de la description des contraintes aux brins. Des estimations réalistes de durées de vie en fatigue des conducteurs sont même possibles par l’application de critères d’endommagement aux contraintes. Ensuite, les pinces de suspension sont intégrées à la stratégie de modélisation selon une représentation surfacique traitant le contact pince/conducteur. Une comparaison à des mesures expérimentales met en relief la précision de l’approche. L’analyse de la solution numérique permet l’identification des zones critiques d’endommagement en contact à chacune des couches du conducteur et révèle des informations nouvelles quant à la nature de la sollicitation des brins à la pince de suspension. Finalement, des travaux exploratoires proposent un nouveau concept d’analyse multi-échelles en combinant la modélisation numérique d’un système pince/conducteur à des essais de fatigue sur brins individuels. Une mise en œuvre préliminaire de l’approche permet de valider le concept et en jette les bases en vue de son application future. En somme, la stratégie de modélisation développée dans cette thèse constitue un puissant outil d’analyse qui ouvre maintenant la voie à une caractérisation appropriée de la fatigue des conducteurs en vue ultimement de prédire leur durée et vie résiduelle. / Abstract : The aging of overhead transmission lines is a major concern for utilities. In particular, problems arise in assessing the integrity of conductors whose exposure to Aeolian vibrations renders them vulnerable to fatigue damage. Occurring mainly at the suspension clamps, conductor fatigue is still difficult to quantify, especially regarding the prediction of their residual life. With the increasing need to optimize the power grid while maintaining its reliability, accurate evaluations of the conductor damage state become crucial. To this matter, a characterization of the stress levels at the wire scale is first required. The main objective of this thesis is therefore to develop a strategy for the modeling and analysis of conductors subjected to wind induced vibrations, allowing an accurate description of the local load conditions, while accounting for the effects of the suspension clamps. A finite element wire strand modeling strategy is first developed based on a 3D beam element discretization, considering all frictional wire interactions. The modeling approach efficiently reproduces the wire strand kinematics while giving access to the local loads. Its general formulation also allows it to be applied to any problem involving strands. Applied to the study of conductors subjected to Aeolian vibrations, the strategy leads to an accurate description of their behavior at both the global strand deformations and the wire stress description. Realistic conductor residual life estimates are even possible with the use of common damage criteria. The suspension clamps are then incorporated into the modeling strategy using a surface representation of the conductor/clamp contact. Comparisons with experimental measurements highlight the precision of the approach. The model response analysis allows now the identification of the critical damage zones within each conductor layers and reveals new information about the nature of the wire stresses at the suspension clamp. Finally, exploratory works propose a new concept of multi-scale analysis combining the numerical conductor/clamp modeling strategy to experimental fatigue tests on individual wires. A preliminary implementation of the approach validates the concept and lays the foundations for its future application. In summary, the modeling strategy developed in this thesis constitutes a powerful analytical tool which now opens the way to an appropriate characterization of conductor fatigue with the ultimate objective to eventually predict their residual life.

La thèse a mis en œuvre deux méthodes inverses pour l’évaluation non destructive d’un milieu multicouche anisotrope : la microscopie acoustique et les courants de Foucault. Pour la microscopie acoustique, nous avons adapté un modèle de propagation de l'onde acoustique dans un milieu multicouche, en calculant les coefficients de réflexion et de transmission d’un revêtement multicouche sur un substrat et en modélisant la réponse acoustique V(z) propre à la microscopie acoustique. Une méthode inverse utilisant l’algorithme de Levenberg-Marquardt donne accès à l’épaisseur, au module de Young et à la densité du revêtement. Pour les courants de Foucault, une méthode inverse similaire basée sur le formalisme de Tree a été mise au point, qui donne accès à l’épaisseur, à la conductivité électrique et à la perméabilité magnétique du revêtement. Après des vérifications de l’algorithme sur des matériaux massifs de référence, nous avons appliqué ces méthodes à un métal revêtu pour tuyauteries de centrale thermique : de l’acier inoxydable austénitique type 304 revêtu par pulvérisation thermique de superalliage Hastelloy C22 à base de nickel. La corrosion sèche sous l’effet des gaz chauds (air contenant du gaz SO2) amincit graduellement la paroi des tubes, ce qui peut les rendre dangereux. Il a fallu tenir compte de l’effet du grenaillage préalable à la pulvérisation, qui crée une mince couche de martensite à laquelle les courants de Foucault sont très sensibles : un modèle à trois couches substrat / martensite / revêtement a été utilisé. Nous avons caractérisé des échantillons de métal avant et après exposition à l’air avec ou sans SO2 à 650°C. Les deux méthodes d’évaluation non destructive permettent une détermination très satisfaisante de l’épaisseur de revêtement et se complètent bien. L’évaluation des caractéristiques physiques (acoustiques et électromagnétiques) met en évidence des hétérogénités du revêtement liées à son mode d’élaboration et des évolutions au cours du temps. Des pistes d’amélioration des méthodes sont proposées. / In the current work, we investigate the nondestructive evaluation of a thermal sprayed coating (Hastelloy C22 Ni-based alloy) on substrate (type 304 austenitic stainless steel) using acoustic microscopy and ECT method. Two models were built for the evaluation of this kind of material: one is for acoustic V(z) measurement and the other is for swept eddy current measurement. The implementation of these two models is used for the evaluation and properties measurement of the thermal sprayed coatings, such as elastic properties, electromagnetic properties. In particular, the main achievements and results are as follows: 1. Acoustic wave propagation in an anisotropic multilayered medium was investigated. The formula for calculating the reflection and transmission coefficients of the multilayered medium on or without a substrate were derived, which is necessary for the modeling of acoustic V(z) measurement of the thermal sprayed coating on substrate. 2. A model was built for the acoustic V(z) measurement of the thermal sprayed coatings on substrate, which can deal with anisotropic multilayered media. Specifically, we used a model of multilayered coatings with graded properties on substrate to calculate the acoustic reflection coefficient of our sample. Treating the thermal sprayed coating, deposited on a 304 steel substrate, as FGMs, we evaluated the coating thickness and the Young’s modulus evolution along the depth of the coating. 3. A model was built for the swept eddy current measurement of the thermal sprayed coatings. Since before the spraying process, the surface of the substrate is usually shot-peened (SP), the coated material is considered as a three-layer medium. The coating thickness and electromagnetic properties of each of the 3 layers were determined by an effective reverse process. 4. The thermal sprayed coated material after exposure in different conditions, i.e., as-received, heat-treated in air and heat-treated in SO2 environment, and after different exposure time was evaluated by the integrity of acoustic microscopy and ECT method. The coating thickness and the electromagnetic properties of the coated material under different conditions were measured.

Les transducteurs ultrasonores capacitifs micro-usinés sont aujourd'hui une nouvelle alternative à la transduction d'ondes ultrasonores. En comparaison avec la technologie piézo-électrique, ils offrent des potentialités en termes de production, de miniaturisation et d'intégration d'une électronique associée mais aussi en termes de performances. Néanmoins,leur mise en œuvre n'en est encore qu'à ces balbutiements et la compréhension de leurs comportements nécessite d'être approfondie. C'est dans ce cadre que s'inscrit le présent travail de thèse. Nous proposons, dans un premier temps, à l'aide d'un modèle numérique basé sur une mécanique linéaire de plaques multicouches, d'étudier l'effet des contraintes initiales sur le comportement statique. Dans un second temps, l'impact de la non-linéarité de la dynamique d'une cellule, puis d'un réseau de cellules, est étudiée en s'appuyant à la fois sur des mesures d'interférométrie et sur un modèle temporel intégrant les effets du fluide. Enfin, nous proposons une optimisation de l'excitation et l'utilisation de ces dispositifs en régime forcée pour la génération d'onde basse fréquence dans l'air et dans l'eau. / Capacitive tvIicromachined Ultrasound Transducers (cMUTs) are today a new alternative for the generation of ultrasonic waves. Compared lo the piezoelectric technology, theyoffer some potentialities in terms of reliability, production, miniaturization and electronicintegration but also in term of acoustic performance. Nevertheless, their implementationis relatively new and the understanding of their static and dynamic behaviors needs to bestudied further. This is in this context that this PhD is developed. We propose, in a firsttime, with the help of a numeric model based on the linear mechanic theory of multilayeredplates, to study the impact of initial stresses on the static behavior. In a second time, the impact of the nonlinearity on the dynamic of the cell first, and a cell array next, is studiedwith the help of a temporal model and measurements made by laser interferometry both.Finally, thanks to this dynamic study, a new operation mode of cMUTs is identified andverified. This one is based on the use of forced regime in air and water of these device togenerate low frequencies ultrasonic waves.

Cette thèse traite des problèmes des concentrations de contraintes locales, en particularité des effets des bords libres dans des structures stratifiés. À l'interface entre deux couches avec des propriétés élastiques différentes, les contraintes ont un comportement singulier dans le voisinage du bord libre en supposant un comportement de matériau élastique linéaire. Par conséquent, ils sont essentiels pour promouvoir le délaminage. Via Formulation unifiée de la Carrera (CUF) différents modèles cinématiques sont testés dans le but de capter les concentrations de contraintes. Dans la première partie de ce travail, les approches de modélisation dimensionnelle réduits sont comparées. Deux classe principale sont présentés: la couche équivalent (ESL) et l'approche par couche, LW. Par la suite leurs capacités à capter les singularités sont comparées. En utilisant une fonction a priori singulière, via une expression exponentielle, une mesure des contraintes singulières est introduite. Seulement deux paramètres décrivent pleinement les composantes des contraintes singulières au voisinage du bord libre. Sur la base des paramètres obtenus les modèles sont comparés et aussi les effets sous des charges d'extension et de flexion et pour différents stratifiés. Les résultats montrent une nécessité des modèles complexes dans le voisinage du bord libre. Cependant loin des bords libres, dans le centre de plaques composite, aucune différence significative ne peut être noté pour les modèles plutôt simples. La deuxième partie de ce travail est donc dédiée au couplage de modèles cinématique incompatibles. Modèles complexes et coûteux sont utilisés seulement dans des domaines locaux d'intérêt, tandis que les modèles économiques simples seront modéliser le domaine global. La eXtended Variational Formulation (XVF) est utilisé pour coupler les modèles de dimensionnalité homogènes mais de cinématique hétérogènes. Ici pas de recouvrement de domaine est présent. En outre, le XVF offre la possibilité d'adapter les conditions imposées à l'interface en utilisant un paramètre scalaire unique. On montre que, pour le problème de dimensionnalité homogène, que deux conditions différentes peuvent être imposées par ce paramètre. Un correspondant à des conditions fortes des Multi Point Constraints (MPC) et un second fournir des conditions faibles. La dernière offre la possibilité de réduire extrêmement le domaine qui utilise le modèle cinématique complexe, sans perte de précision locale. Comme il s'agit de la première application de la XVF vers les structures composites, le besoin d'un nouvel opérateur de couplage a été identifié. Un nouveau formulaire est proposé, testé et sa robustesse sera évaluée. / This work considers local stress concentrations, especially the free-Edge effects of multilayered structures. At the interface of two adjacent layers with different elastic properties, the stresses can become singular in the intermediate vicinity of the free edge. This is valid while assuming a linear elastic material behaviour. As a consequence this zones are an essential delamination trigger. Via the Carrera Unified Formulation (CUF), different kinematical models are testes in order to obtain the correct local stress concentration. In the first part of this work, the reduced dimensional modelling approaches are compared. Two main class are presented: Equivalent Single Layer (ESL) models treating the layered structure like one homogenous plate of equal mechanical proper- ties, and the Layer Wise approach, treating each layer independently. Subsequently their capabilities to capture the appearing singularities are compared. In order to have a comparable measurement of those singularities, the obtained stress distributions will be expressed via a power law function, which has a priori a singular behaviour. Only two parameters fully describe therefore the singular stress components in the vicinity of the free edge. With the help of these two parameters not only the different models capabilities will be compared, but also the free edge effect itself will be measured and compared for different symmetrical laminates and the case of extensional and uniform bending load. The results for all laminates under both load cases confirm the before stated need for rather complex models in the vicinity of the free edge. However far from the free edges, in the composite plates centre, no significant difference can be noted for rather simple models. The second part of this work is therefore dedicated to the coupling of kinematically incompatible models. The use of costly expensive complex models is restricted to local domains of interest, while economic simple models will model the global do- main. The Extended Variational Formulation (XVF) is identified as the most suitable way to couple the kinematically heterogenous but dimensional homogenous models. As it uses a configuration with one common interface without domain overlap, the additional efforts for establishing the coupling are limited. Further the XVF offers the possibility to adapt the conditions imposed at the interface using a single scalar parameter. It will be shown that for the homogenous dimensional problem under consideration only two different conditions can be imposed by this parameter. One matching the strong conditions imposed by the classical Multi Point Constrains (MPC) and a second one providing a weak condition. The last one is shown to provide the possibility to reduce further the domain using the complex kinematical model, without the loss of local precision. As this is the first application of the XVF towards composite structures, the need for a new coupling operator was identified. A new form is proposed, tested and its robustness will be evaluated.

Good estimates of soil hydraulic parameters and their distribution in a catchment is essential for crop and hydrological models. Measurements of soil properties by experimental methods are expensive and often time consuming, and in order to account for spatial variability of these parameters in the catchment, it becomes necessary to conduct large number of measurements. Estimation of soil parameters by inverse modelling using observations on either surface soil moisture or crop variables has been successfully attempted in many studies, but difficulties to estimate root zone properties arise for heterogeneous layered soils. Although extensive soil data is becoming more and more available at various scales in the form of digital soil maps there is still a large gap between this available information and the input parameters needed for hydrological models. Inverse modeling has been extensively used but the spatial variability of the parameters and insufficient data sets restrict its applicability at the catchment scale. Use of remote sensed soil moisture data to estimate soil properties using the inverse modeling approach received attention in recent years but yielded only an estimate of the surface soil properties. However, in multilayered and heterogeneous soil systems the estimation of soil properties of different layers yielded poor results due to uncertainties in simulating root zone soil moisture from remote sensed surface soil moisture. Surface soil properties can be estimated by inverse approach using surface soil moisture data retrieved from remote sensing data. Since soil moisture retrieved from remote sensing is representative of the top 5 cm only, inversion of models using surface soil moisture cannot give good estimates of soil properties of deeper layers. Crop variables like biomass and leaf area index are sensitive to the deeper layer soil properties. The main focus of this study is to develop a methodology of estimation of root zone soil hydraulic properties in heterogeneous soils by crop model based inversion techniques. Further the usefulness of the radar soil moisture and leaf area index in retrieving soil hydraulic properties using the develop approach is be tested in different soil and crop combinations. A brief introduction about the soil hydraulic properties and their importance in agro-hydrological model is discussed in Chapter 1. Soil water retention parameters are explained in detail in this chapter. A detailed review of the literature is presented in chapter 2 to establish the state of art on the following: (i) estimation of soil hydraulic properties, (ii) role of crop models in estimating soil hydraulic properties, (iii) retrieval of surface soil moisture using water cloud model from SAR data, (iv) retrieval of leaf area index from SAR (synthetic aperture radar) data and (v) modeling of root zone soil moisture and potential recharge. The thesis proposes a methodology for estimating the root zone soil hydraulic properties viz. field capacity, wilting point and soil thickness. To test the methodology developed in this thesis for estimating the soil hydraulic properties and their uncertainty, three synthetic experiments were conducted by inversion of STICS (Simulateur mulTIdiscplinaire pour les Cultures Standard) model for maize crop using the GLUE (Generalized Likelihood Uncertainty Estimation) approach. The estimability of soil hydraulic properties in a layer-wise heterogeneous soil was examined with several sets of likelihood combinations, using leaf area index, surface soil moisture and above ground biomass. The robustness of the approach is tested with parameter estimation (model inversion) in two different meteorological conditions. The details of the numerical experiments and the several likelihood and meteorological cases examined are given in Chapter 3. The likelihood combination of leaf area index and surface soil moisture provided consistently good estimates of soil hydraulic properties for all soil types and different meteorological cases. Relatively wet year provided better estimates of soil hydraulic properties as compared with a dry year. To validate the approach of estimating root zone soil properties and to test the applicability of the approach in several crops and soil types, field measurements were carried out in the Berambadi experimental watershed located in the Kabini river basin in south India. The profile soil measurements were made for every 10 cm upto 1 m depth. Maize, Marigold, Sunflower, Sorghum and Turmeric crops were monitored during the four year period from 2010 to 2013. Crop growth parameters viz. leaf area index, above ground biomass, yield, phenological stages and crop management activities were measured/monitored at 10 day frequency for all the five crops in the study area. The details of the field experiments performed, the data collected and the results of the model inversion using the ground measured data are given in Chapter 4. The likelihood combination of leaf area index and surface soil moisture provided consistently lower root mean square error (1.45 to 2.63 g/g) and uncertainty in the estimation of soil hydraulic properties for all soil crop and meteorological cases. The uncertainty in the estimation of soil hydraulic properties was lower in the likelihood combination of leaf area index and soil moisture. Estimability of depth of root zone showed sensitivity to the rooting depth. Estimating root zone soil properties at field plot scale using SAR data (incidence angle 24o, wave length 5.3 GHz) of RADARSAT-2 is presented in the Chapter 5. In the first step, an approach of estimating leaf area index from radar vegetation index using the parametric growth curve of leaf area index and the retrieval of soil moisture using water cloud model are given in Chapter 5. The parameters of the growth curve and the leaf area index are generated using a time series of RADARSAT-2 for two years 2010-2011 and 2011-12 for the crops (maize, marigold, sunflower, sorghum and turmeric) considered in this study. The surface soil moisture is retrieved using the water cloud model, which is calibrated using the ground measured values of leaf area index and surface soil moisture for different soils and crops in the study area. The calibration and validation of LAI and water cloud models are discussed in this Chapter. Eventually, the retrieved leaf area index and surface soil moisture from RADARSAT-2 data were used to estimate the soil hydraulic properties and their uncertainty in a similar manner as discussed in Chapter 4 for various crop and soil plots and the results are presented in Chapter 5. The mean and uncertainty in the estimation of soil hydraulic properties using inversion of remote sensing data provided results similar to the estimates from inversion of ground data. The estimates of soil hydraulic properties compared well (R2 of 0.7 to 0.80 and RMSE of 2.1 to 3.16 g/g) with the physically measured vales of the parameters. In Chapter 6, root zone soil moisture and potential recharge are modelled using the STICS model and the soil hydraulic parameters estimated using the RADARSAT-2 data. The potential recharge is highly sensitive to the water holding capacity of rooting zone. Variability in the root zone soil moisture for wet and dry years for different soil types on irrigated and non-irrigated crops were investigated. Potential recharge from different crop and soil types were compared. The uncertainty in the estimation of potential recharge due to uncertainty in the estimation of field capacity is quantified. The root zone soil moisture modeled by STICS showed good agreement with the measured root zone soil moisture in all crop and soil cases. This was tested for both dry and wet year and provides similar results. The temporal variability of root zone soil moisture was also modeled well by the STICS model; the model also predicted well the intra-soil variability of soil moisture of root zone. The results of the modeling of root zone soil moisture and potential recharge are presented in Chapter 6. At the end, in Chapter 7, the major conclusions drawn from the various chapters are summarized.

[EN] The aim of this work is to demonstrate theoretically and experimentally how acoustic wave propagation can be controlled by temperature gradients. Starting with the simplest case of two hot wires in air the study extends over periodic structures known as Sonic Crystals (SCs). The Finite Elements Method (FEM) has been employed to perform numerical simulations in order to demonstrate collimation and focusing effect of acoustic waves in two-dimensional (2D) SC whose filling fraction is adjusted by temperature gradients. As a part of the research, Bragg reflection and Fabry-Perot type of acoustic effects are investigated for the proposed type of SC. As example, a SC with desired transmittance can be tailored. Also, gradient index (GRIN) 2D sonic lenses are studied. Using parallel rows of heated wires whose temperatures vary according to a prefixed gradient index law a GRIN lens can be designed with a given performance. Moreover, by changing the temperature of the wires a change in the filling fraction inside the GRIN SC can be achieved. Thus, the local refraction index, which is directly related to the filling fraction, is changed too and an index gradient variation inside the GRIN SC is obtained. This GRIN SC is a direct analogy of gradient media observed in nature. Like their optical counterparts, the investigated 2D GRIN SC lenses have flat surfaces and are easier for fabrication than curved SC lenses. The bending of sound waves obtained by GRIN acoustics structures can be used to focusing and collimating acoustic waves. Another aspect of this work is about tuning some SC properties as effective refractive index, effective mass density, etc. in order to obtain a SC with prefixed properties. Since active tuning of the phononic band gaps is certainly desirable for future applications with enhanced functionalities, few attempts have been made to develop tunable SCs thus far. By controlling the incident angle or operating frequency, a GRIN SC can dynamically adjust the curved trajectory of acoustic wave propagation inside the SC structure. Among the last studies of tunable SCs, the filling fractions were tuned either by direct physical deformation of the structure or external stimuli. The former is impractical for most applications and the latter often requires very strong stimuli to produce only modest adjustment. In this work another way to tune the SC properties is proposed. Hot and cold media have different density, speed of sound, refractive index, etc. in comparison with the same properties at normal conditions, so inserting temperature gradients inside the medium can be used to tune the SC properties in certain limits. The proposed way to obtain temperature gradients inside SC is by wires made of Nicrom which are heated by electrical currents. There are some important advantages of this method. First, changing the electrical current intensity through the wires the SC properties can be changed dynamically. Second, it is relatively easier to change the filling fraction simply by adjusting the current intensity than physically changing the structure or applying strong electric or magnetic fields. In conclusion, the method proposed in this thesis allows us, in principle, to get materials and structures with dynamically adjustable acoustic properties using the temperature control through electric current in the wires, within certain limits. Thus, it is easy to carry out experiments of wave propagation phenomena in a macroscopic scale similar to those that occur in microscopic structures for the propagation of electromagnetic waves of high frequency (microwaves and light). / [ES] El objetivo de este trabajo es demostrar teoréticamente y experimentalmente como la propagación de ondas acústicas puede ser controlada por gradientes de temperatura. Empezando con el caso más simple de dos hilos calientes en aire, el estudio se extiende sobre estructuras periódicas conocidas como cristales sónicos (CS). Se ha utilizado el Método de Elementos Finitos (FEM) para realizar simulaciones numéricas con el objetivo de demonstrar la colimación y focalización de ondas acústicas en CS bidimensionales (2D) cuya fracción de llenado es ajustable mediante gradientes de temperatura. Como parte de la investigación se ha analizado la reflexión de Bragg y el efecto de tipo Fabry-Perot asociados con los CSs estudiados. Entre los ejemplos tratados figuran un CS con una transmitancia ajustable a voluntad, dentro de ciertos límites. También se han estudiado lentes acústicas bidimensionales de gradiente de índice, basadas en gradiente de temperatura. Utilizando cortinas paralelas de hilos calientes cuya temperatura varía según una ley dada se puede diseñar una lente GRIN con propiedades determinadas. Por otra parte, cambiando la temperatura de los hilos se puede lograr un cambio en la fracción de llenado dentro del GRIN CS. Así, el índice de refracción local, que está directamente relacionado con la fracción de llenado, se cambia también y se obtiene una variación de gradiente de índice dentro del GRIN CS. Este GRIN CS es una analogía directa de medios con gradiente, observados en la naturaleza. Otro aspecto de este trabajo trata sobre el ajuste de algunas propiedades de un SC como el índice de refracción efectivo o la densidad efectiva con el objetivo de obtener unas propiedades deseadas del cristal. Como el ajuste activo de los bandgaps fonónicos es ciertamente deseado para futuras aplicaciones con funcionalidades mejoradas, hasta ahora se han hecho varios intentos de desarrollar CSs de características ajustables. Controlando el ángulo de incidencia o la frecuencia de funcionamiento, un GRIN CS puede ajustar dinámicamente la curvatura de la trayectoria de propagación dentro de la estructura CS. Entre los últimos estudios de CSs las fracciones de llenado se ajustaron mediante una deformación física directa de la estructura o mediante estímulos externos (por ejemplo campos eléctricos o magnéticos). El primero es poco práctico para una gran parte de las aplicaciones y el segundo a menudo requiere estímulos muy fuertes para ajustes modestos. En este trabajo se propone otra forma de ajustar las propiedades de un CS. Las propiedades acústicas del medio de propagación (densidad, índice de refracción) dependen de la temperatura, por tanto, introduciendo gradientes de temperatura dentro de dicho medio pueden ajustarse a voluntad las propiedades del CS dentro de ciertos límites. La manera de obtener gradientes de temperatura dentro del CS, propuesta en este estudio, es mediante hilos de nicrom calentados con corrientes eléctricas. Hay algunas ventajas importantes de este método. En primer lugar, cambiando la intensidad de corriente eléctrica que circula por los hilos se puede conseguir cambiar dinámicamente las propiedades del CS. En segundo lugar, es relativamente más fácil de cambiar la fracción de llenado simplemente ajustando la intensidad de la corriente eléctrica que modificar físicamente la estructura o aplicar fuertes campos eléctricos o magnéticos. En conclusión, el método propuesto en esta tesis permite, en principio, conseguir materiales y estructuras con propiedades acústicas ajustables dinámicamente mediante el control de la temperatura a través de la corriente eléctrica en los hilos, dentro de ciertos límites. De esta forma se puede experimentar fácilmente a escala macroscópica fenómenos de propagación de ondas análogos a los que ocurren en estructuras microscópicas para la propagación de ondas electromagnéticas de alta frecuencia (microondas y l / [CAT] L'objectiu d'este treball és demostrar teorèticament i experimentalment com la propagació d'ones acústiques pot ser controlada per gradients de temperatura. Començant amb el cas més simple de dos fils calents en aire, l'estudi s'estén sobre estructures periòdiques conegudes com a cristalls sónics (CS) . S'ha utilitzat el Mètode d'Elements Finits (FEM) per a realitzar simulacions numèriques amb l'objectiu de demonstrar la col¿limació i focalització d'ones acústiques en CS bidimensionals (2D) la fracció de omplit de la qual és ajustable per mitjà de gradients de temperatura. Com a part de la investigació s'ha analitzat la reflexió de Bragg i l'efecte de tipus Fabry-Perot associats amb els CSs estudiats. Entre els exemples tractats figuren un CS amb una transmitancia ajustable a voluntat, dins de certs límits. També s'han estudiat lents acústiques bidimensionals de gradient d'índex, basades en gradient de temperatura. Utilitzant cortines paral¿leles de fils calents la temperatura de la qual varia segons una llei donada es pot dissenyar una lent GRIN amb propietats determinades. D'altra banda, canviant la temperatura dels fils es pot aconseguir un canvi en la fracció d'ompliment dins del GRIN CS. Així, l'índex de refracció local, que està directament relacionat amb la fracció d'ompliment, es canvia també i s'obté una variació de gradient d'índex dins del GRIN CS. Este GRIN CS és una analogia directa de mitjans amb gradient, observats en la naturalesa. Com les seues analogies òptiques, les lents, estudiades en este treball, tenen les superfícies planes i són més fàcils de fabricar que les lents corbades. La deflexión de les ones acústiques obtinguda per mitjà d'una lent de gradient GRIN es pot utilitzar per a focalitzar o colimar feixos de so. Un altre aspecte d'este treball tracta sobre l'ajust d'algunes propietats d'un SC com l'índex de refracció efectiu o la densitat efectiva amb l'objectiu d'obtindre unes propietats desitjades del cristall. Com l'ajust actiu dels bandgaps fonónicos és certament desitjat per a futures aplicacions amb funcionalitats millorades, fins ara s'han fet diversos intents de desenrotllar CSs de característiques ajustables. Controlant l'angle d'incidència o la freqüència de funcionament, un GRIN CS pot ajustar dinàmicament la curvatura de la trajectòria de propagació dins de l'estructura CS. Entre els últims estudis de CSs les fraccions d'ompliment es van ajustar per mitjà d'una deformació física directa de l'estructura o per mitjà d'estímuls externs. El primer és poc pràctic per a una gran part de les aplicacions i el segon sovint requerix estímuls molt forts per a ajustos modestos. En este treball es proposa una altra forma d'ajustar les propietats d'un CS. Les propietats acústiques del mig de propagació (densitat, índex de refracció) depenen de la temperatura, per tant, introduint gradients de temperatura dins del dit mitjà poden ajustar-se a voluntat les propietats del CS dins de certs límits. La manera d'obtindre gradients de temperatura dins del CS, proposta en este estudi, és per mitjà de fils de Nicrom calfats amb corrents elèctrics. Hi ha alguns avantatges importants d'este mètode. En primer lloc, canviant la intensitat de corrent elèctric que circula pels fils es pot aconseguir canviar dinàmicament les propietats del CS. En segon lloc, és relativament més fàcil de canviar la fracció d'ompliment simplement ajustant la intensitat del corrent elèctric que modificar físicament l'estructura o aplicar forts camps elèctrics o magnètics. En conclusió, el mètode proposat en esta tesi permet, en principi, aconseguir materials i estructures amb propietats acústiques ajustables dinàmicament per mitjà del control de la temperatura a través del corrent elèctric en els fils, dins de certs límits. D'esta manera es pot experimentar fàcilment a escala macroscòpica fenòmens de propagació d'ones anàlegs a què ocorren e / Ivanov Angelov, M. (2016). Sound Scattering by Lattices of Heated Wires [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63275 / TESIS

Die Entwicklung von Geweben mit gestreckten Fadenlagen ist Gegenstand aktueller Forschungen, die vielfach Sondermaschinen für ganz spezielle Anwendungen hervorbringen. Eine systematische Analyse und Optimierung der unter Berücksichtigung der Verbundeigenschaften existiert nach bekanntem Stand des Wissens nicht. Ziel der Dissertation ist es, diese Lücke zu schließen und einen Beitrag zur Etablierung von Geweben mit gestreckten Fadenlagen in Faserverbundwerkstoffen zu leisten. Die Arbeit basiert zum Teil auf den Ergebnissen, die in der Zeit von 2006 – 2012 am Institut für Textilmaschinen und textile Hochleistungswerkstofftechnik der Technischen Universität Dresden im Rahmen verschiedener AiF und DFG Vorhaben entstanden sind. Weiterführende Überlegungen wurden 2015 – 2017 im Rahmen eines Promotionsstudiums an der Professur für Textile Technologien der Technischen Universität Chemnitz angefertigt. Wie anhand konkreter Ausführungsbeispiele gezeigt wird, stößt das Weben insbesondere für Anwendungen im Faserverbundleichtbau an technologisch bedingte Grenzen. Es erfolgt zunächst eine Gegenüberstellung konventioneller Flächenbildungsverfahren und der Anforderungen seitens der Endanwender, insbesondere aus dem Bereich der Verbundwerkstoffindustrie, gleichermaßen. Daraus wird ein Anforderungsprofil für ein anforderungsgerechtes Flächenbildungsverfahren abgeleitet und konstruktive Lösungsvorschläge zu dessen Umsetzung aufgezeigt. / The development of non-crimped-fabrics (NCF) is subject of current research activities. These often led to special machines for very special applications. There is no systematic analysis and optimization of the properties of composites based on the state of the art. The aim of this dissertation is to close this gap and to contribute to the establishment of woven NCF in fiber-reinforced composites. The work is based partially on the results obtained at the Institut für Textilmaschinen und textile Hochleistungswerkstofftechnik der Technischen Universität Dresden from 2006 to 2012 within the framework of various AiF and DFG projects. Further reflections were made between 2015 and 2017 as part of a doctoral study at the Chair of Textile Technologien der Technischen Universität Chemnitz. As shown from examples of the design, weaving is reaching technological limits, especially for applications in composite construction. First of all, conventional surface formation methods are compared with the requirements of end users, especially from the composites industry. From this, a requirement profile is derived for a requirements-based surface formation process and constructive proposals for solutions for its implementation are identified.

Rudyard Kipling is a man of immense diversity. He successfully managed to write for over half a century in a variety of genres: short story, travelogue, ballad, personal narrative, and news reporting, to name only a few. While doing so, Kipling readily interacted with a range of subjects and created a multitude of ideas. Likewise, on a personal level, Kipling led an immensely diverse life. He could easily claim four separate continents as home, living variously in India, the United States, England, and South Africa. By profession he was a writer, but as an observer he was so skilled that he learned by heart a variety of professions ranging from street beggar to statesman. Both before and after his life, this variety and complexity has been a subject of debate. Some ignore it, others focus on a particular side of it, but for all it represents an interesting challenge in both studying and classifying Kipling. This thesis seeks to address that challenge by focusing on how Kipling's varying and competing images and ideas work together to assert Kipling's independence. In doing so, this work will look specifically at how Kipling uses multifaceted techniques in his public speeches. In looking at the speeches, the thesis explores three ways in which multiplicity reinforces independence: the combination of privacy and creation, the refashioning of expert detail and self-image, and the fusion of simplistic structure and subtle complexity.

В данной работе представлены исследования характеристик металлического круглого волновода с неоднородным диэлектрическим заполнением и одномодового оптического волокна. Были построены и проанализированы частотные зависимости постоянной распространения для следующих диэлектрических структур круглого волновода: стержень, втулка, цилиндр, цилиндр с зазором, стержень с параболическим профилем изменения относительной диэлектрической проницаемости. Были рассмотрены одномодовые оптические волокна с разным профилем преломления и изучены материальная и хроматическая дисперсия одномодового волокна. / This work contains researches of characteristics of inhomogeniously filled metal circular waveguide and single-mode optical fiber. Frequency dependences of propagation constant of following dialectic structures in circular waveguide were calculated and analyzed: rod, plug, cylinder, cylinders with air gap, rod with parabolic permittivity profile. Characteristics of single-mode optical fiber with different refractive index profiles were considered, alsomaterial and chromatic dispersions were explored.

<p>Докторска дисертација припада области информационих система, са јасним акцентом на употребу неуронских мрежа за решавање проблема вишеструких зависних временских серија&nbsp; који је у&nbsp; овом докторату дефинисан.Основни циљ дисертације је креирање система у форми едукативног софтвера путем којег ће се обучавати младе кошаркашке судије</p><p>Један од кључих елемената овог&nbsp; доктората јесте симулација хоризонталног видног поља на основу којег се&nbsp; утврђује да ли је резоновано кретање кошаркашких судија било адекватно&nbsp; или није. Стога развијени софтвер поседује споменуту едукативну примену.</p><p>Како би се реализовао споменути софтвер спроведено је истраживање које је обухватило обучавање великог броја традиционалних вишеслојних перцептрона као и формирање посебне&nbsp; LTR&nbsp; &ndash;&nbsp; MDTS структуре неуронске мреже за коју се сматра да је погодна за решавање постојећег проблема. За реализацију симулације хоризонталног видног поља разматрано је више алгоритама из области рачунарске графике&nbsp; а&nbsp; Sweep and Prune&nbsp; алгоритам је парцијално пружио основу за развијени и тренутно&nbsp; имплементирани алгоритам.</p> / <p>Doktorska disertacija pripada oblasti informacionih sistema, sa jasnim akcentom na upotrebu neuronskih mreža za rešavanje problema višestrukih zavisnih vremenskih serija&nbsp; koji je u&nbsp; ovom doktoratu definisan.Osnovni cilj disertacije je kreiranje sistema u formi edukativnog softvera putem kojeg će se obučavati mlade košarkaške sudije</p><p>Jedan od ključih elemenata ovog&nbsp; doktorata jeste simulacija horizontalnog vidnog polja na osnovu kojeg se&nbsp; utvrđuje da li je rezonovano kretanje košarkaških sudija bilo adekvatno&nbsp; ili nije. Stoga razvijeni softver poseduje spomenutu edukativnu primenu.</p><p>Kako bi se realizovao spomenuti softver sprovedeno je istraživanje koje je obuhvatilo obučavanje velikog broja tradicionalnih višeslojnih perceptrona kao i formiranje posebne&nbsp; LTR&nbsp; &ndash;&nbsp; MDTS strukture neuronske mreže za koju se smatra da je pogodna za rešavanje postojećeg problema. Za realizaciju simulacije horizontalnog vidnog polja razmatrano je više algoritama iz oblasti računarske grafike&nbsp; a&nbsp; Sweep and Prune&nbsp; algoritam je parcijalno pružio osnovu za razvijeni i trenutno&nbsp; implementirani algoritam.</p> / <p>Doctoral dissertation belongs to the field of information systems, with a clear&nbsp; emphasis on the use of neural networks for solving the problem of multiple dependent time series, which is defined in this doctorate. The main objective of the&nbsp; thesis is to create a system in the form of educational software that will be used druring the training of young basketball referees.One of the key elements of this doctorate is a simulation of a horizontal field of&nbsp; vision&nbsp; on the basis of which it is determined whether the movement of&nbsp; reasoned&nbsp; basketball referees was adequate &nbsp; or not.&nbsp; Therefore developed software has&nbsp; aforementioned educational use. In order&nbsp; to realize the aforementioned software, a&nbsp; research&nbsp; was conducted that included training of a large number of traditional multilayer perceptron neural networks and the&nbsp; formation of special LTR&nbsp; -&nbsp; MDTS&nbsp; neural network&nbsp; structure which is considered to be&nbsp; suitable&nbsp; for solving the presented problem. For the realization of the simulation&nbsp; of the horizontal field of vision a large number of algorithms in the field of computer graphis was considered&nbsp; and Sweep and Prune algorithm partially provided the basis for the developed and&nbsp; currently implemented algorithm.</p>