The theory of electromagnetic characteristic modes was published roughly forty years ago, for both conducting and penetrable objects. However, while the characteristic mode analysis of conducting objects has found renewed interest as a tool for antenna designers, computed results for the characteristic mode eigenvalues, eigencurrents and eigenfields for penetrable objects have not appeared, not even in the seminal papers on the subject. In this thesis both volume and surface integral equation formulations are used to compute the characteristic modes of penetrable objects for what appears to be the first time. This opens the way for the use of characteristic mode theory in the design of antennas made of penetrable material whose polarization current densities constitute the main radiating mechanism of the antenna. Volume formulations are shown to be reliable but computationally burdensome. It is demonstrated that surface formulations are computationally more efficient, but obtrude some non-physical modes in addition to the physical ones. Fortunately, certain field orthogonality checklists can be used to provide a straightforward means of unambiguously selecting only the physical modes. The sub-structure characteristic mode concept is extended to problems involving both perfectly conducting and penetrable materials. It is also argued that sub-structure modes can be viewed as characteristic modes that implicitly use modified Green’s functions, but without such Green’s functions being needed explicitly. This makes the concept really practical, since the desired modified Green’s functions are not known explicitly in most cases.

The theory of electromagnetic characteristic modes was published roughly forty years ago, for both conducting and penetrable objects. However, while the characteristic mode analysis of conducting objects has found renewed interest as a tool for antenna designers, computed results for the characteristic mode eigenvalues, eigencurrents and eigenfields for penetrable objects have not appeared, not even in the seminal papers on the subject. In this thesis both volume and surface integral equation formulations are used to compute the characteristic modes of penetrable objects for what appears to be the first time. This opens the way for the use of characteristic mode theory in the design of antennas made of penetrable material whose polarization current densities constitute the main radiating mechanism of the antenna. Volume formulations are shown to be reliable but computationally burdensome. It is demonstrated that surface formulations are computationally more efficient, but obtrude some non-physical modes in addition to the physical ones. Fortunately, certain field orthogonality checklists can be used to provide a straightforward means of unambiguously selecting only the physical modes. The sub-structure characteristic mode concept is extended to problems involving both perfectly conducting and penetrable materials. It is also argued that sub-structure modes can be viewed as characteristic modes that implicitly use modified Green’s functions, but without such Green’s functions being needed explicitly. This makes the concept really practical, since the desired modified Green’s functions are not known explicitly in most cases.

Le travail présenté dans cette thèse vise à comprendre les vibrations de pièce mince durant l’usinage. De nombreux travaux proposent des modélisations de ce phénomène, mais des écarts persistent entre résultats de modélisation et réalité. Ce constat nous pousse à nous interroger sur l’emploi dans les modèles des modes propres de la pièce, sans y intégrer le contact de l’outil. Face à l’incapacité de vérifier la validité de cette hypothèse par mesures ponctuelles, la mesure de champ s’impose comme une alternative prometteuse. La deuxième partie du travail porte sur la mise au point d’un protocole expérimental novateur. Il inclut le relevé des déformées vibratoires d’une pièce mince en usinage par mesure de champs de déplacements. La stéréo corrélation d’images numériques se confronte à de nombreuses limitations dans ce contexte. Nous avons développé une méthode de réglage des capteurs permettant de contourner rapidement certaines difficultés. Cette méthode présentée sous forme graphique souligne la nécessité d’optimiser les paramètres de mesure dans un tel contexte. La troisième partie met en oeuvre le protocole de mesures. Le test des capteurs montre le fort intérêt de la mesure sans contact vis-à-vis de l’objectif recherché. Des essais d’usinage sont présentés en se basant sur une modélisation existante du broutement. Les déformées mesurées pendant l’usinage livrent des informations d’un type nouveau. Leur exploitation a impliqué la mise en place d’une procédure spécifique de traitement. La dernière partie présente les analyses de deux usinages. L’étude est effectuée au regard des états de surface obtenus, du comportement temporel, fréquentiel, et spatial. Cette approche souligne les subtilités de la génération d’état de surface en la présence de vibrations. L’examen des mesures de champs permet de relever des incohérences avec l’emploi des modes propres, classiquement utilisés en modélisation. / The work presented in this thesis aims at understanding thin part vibrations during machining. Many works propose modelings of this phenomenon but differencies still exist between modeling results and tests. This observation lead us to wonder about the employment of natural modes of the part in the models, without taking into account the tool presence. The fact that punctual measurements don’t enable to verify the validity of this hypothesis, field measurement prove to be a hopeful alternative. The second part focuses on adjusting a novel experimental protocol. It includes the recording of the thin part vibrating shapes by displacement field measurement. Digital Image Stereo Correlation is confronted to many limitations in this context. We developed a method to set sensors enabling the quick avoidance of difficulties. This method is presented in a graphical form, and underlines the need of optimising measurement parameters in such an environment. In the third part of the work, the measurement protocol is used. The sensors testing shows the high interest of contactless measurement for the aimed goal. Machininng tests are presented in connection with an existing model of chatter. The measured shapes during machining give a new sort of informations. So, their analyse implied the building of a specific processing procedure. The last part presents analyses of two machining tests. The study is done by parallely looking at the machined surface, and the behavior in temporal and frequency space as so as the part displacement fields. This approach underlines subtleties of surface generation under vibration conditions. The fields inspection enables to mark inconsistencies if employing the natural modes that are classically used in models.

[Truncated abstract] Internal waves redistribute energy and momentum in stratified lakes and constitute the path through which the energy that is introduced at the lake scale is cascaded down to the turbulent scales where mixing and dissipation take place. This research, based on intensive field data complemented with numerical simulations, covers several aspects of the energy flux path ranging from basin-scale waves with periods of several hours to high frequency waves with periods of few minutes. It was found that, at the basin-scale level, the horizontal shape of the lake at the level of the metalimnion controls the period and modal structure of the basin-scale natural modes, conforming to the dispersion relationship of internal waves in circular basins. The sloping bottom, in turn, produces local intensification of the wave motion due to focusing of internal wave rays over near-critical slopes, providing hot spots for the degeneration of the basin-scale waves due to shear instabilities, nonlinear processes and dissipation. Different types of high-frequency phenomena were observed in a stratified lake under different forcing conditions. The identification of the generation mechanisms revealed how these waves extract energy from the mean flow and the basin-scale waves. The changes to the stratification show that such waves contribute to mixing in different ways . . . Detailed field observations were used to develop a comprehensive description of an undocumented energy flux mechanism in which shear-instabilities with significant amplitudes away from the generation level are produced in the surface layer due to the shear generated by the wind. The vertical structure of these instabilities is such that the growing wave-related fluctuations strain the density field in the metalimnion triggering secondary instabilities. These instabilities also transport energy vertically to the thermocline where they transfer energy back to the mean flow through interaction with the background shear.

The aim of this masters thesis is a design of a suspended pedestrian bridge over a watercourse. There are two variants designed, one of which is selected for static analysis. The chosen variant is a suspended pedestrian bridge with an inclined „A“ shaped pylon situated on one bank and deck made of prefabricated segments. The cross-section is designet to allow the transfer of both pedestrian and bycicle traffic. Thesis contains structural design of construction modeled in SCIA Engineer and checked in IDEA Statica. Design and assessment are acordign to the current European standarts.

The purpose of the study is the investigation of the topics of transposition and the transposed major and minor modes as discussed principally by selected French authors of the final twenty years of the seventeenth century and the first three decades of the eighteenth. The sources are relatively varied and include manuals for singers and instrumentalists, dictionaries, independent essays, and tracts which were published in scholarly journals; special emphasis is placed on the observation and attempted explanation of both irregular signatures and the signatures of the minor modes. The paper concerns the following areas: definitions and related concepts, methods for singers and Instrumentalists, and signatures for the tones which were identified by the authors. The topics are interdependent, for the signatures both effected transposition and indicated written-out transpositions. The late Baroque was characterized by much diversity with regard to definitions of the natural and transposed modes. At the close of the seventeenth century, two concurrent and yet diverse notions were in evidence: the most widespread associated "natural" with inclusion within the gamme; that is, the criterion for naturalness was total diatonic pitch content, as specified by the signature. When the scale was reduced from two columns to a single one, its total pitch content was diminished, and consequently the number of the natural modes found within the gamme was reduced. An apparently less popular view narrowed the focus of "natural tone" to a single diatonic pitch, the final of the tone or mode. A number of factors contributed to the disappearance of the long-held distinction between natural and transposed tones: the linking of the notion of "transposed" with the temperament, the establishment of two types of signatures for the minor tones (for tones with sharps and flats, respectively), the transition from a two-column scale to a single-column one, and the recognition of a unified system of major and minor keys.

The Theory of Characteristic Modes is being adopted by many research groups around the world in the last decade. This topic and their use in different metallic antenna design is growing very fast. However, most of the applications has been only concentrated on conducting surfaces without any physical knowledge about its limitations and its physical interpretation. As far as dielectric bodies are concerned, there have not been so many published articles. The reason is that there are different integro-differential formulations and the interpretation of their solutions is not as obvious as in conducting bodies. Here, a theoretical interpretation considering loss-less conducting and dielectric bodies is presented. The conclusions drawn in this thesis will allow us to better understand the solutions of the Theory of Characteristic Modes and their limitations. This is important for antenna engineering. In addition, this analysis will allow to develop a novel method for the design of antennas based on dielectric resonators, DRA. This method is called Substructure based-PMCHWT method, and is based on the implementation of the Schur complements of the method of moments matrix operator. This study permits to optimize the radiation bandwidth in the same analysis process for both, the dielectric and the feed, e.g. slot. Moreover, it allows to understand how the slot behaves in the presence of the dielectric resonator and vice versa. This method can also be used to design DRA using low permittivities. This is important in the design of DRA because the feed perturbs the system and produces a shift in the resonances of the characteristic modes. So, therefore, by considering the feed system in the characteristic modes analysis a more realistic results than a conventional analysis is obtained. On the other hand, the resonances of the characteristic modes at low permittivities are displaced from what are the natural resonances of the dielectric resonator and also the corresponding S11 resonance. Thus, designing with this new method it can draw new conclusions about the design of DRA using the Theory of Characteristic Modes. / En la última década, la teoría de los modos característicos está siendo utilizada por muchos grupos de investigación en todo el mundo. Este tema y su uso en diferentes diseños de antenas metálicas está creciendo muy rápido. Sin embargo, la mayoría de las aplicaciones se han concentrado únicamente en antenas metálicas sin ningún conocimiento físico acerca de sus limitaciones y su interpretación física. En lo que se refiere a cuerpos dieléctricos, no han habido tantos artículos publicados como en metales. La razón es que existen diferentes formulaciones integro-diferenciales y la interpretación de sus soluciones no es tan obvia como en cuerpos metálicos. En esta tesis se presenta una interpretación física de las soluciones de la Teoría de Modos Característicos al considerar cuerpos metálicos y dieléctricos sin pérdidas. Las conclusiones de esta tesis nos permitirán comprender mejor las soluciones de la Teoría de Modos Característicos y sus limitaciones. Esto es importante en ingeniería de antenas. Además, este análisis permitirá desarrollar un nuevo método para el diseño de antenas basadas en resonadores dieléctricos, DRA. Este método está basado en la formulación PMCHWT y la función de Green multicapa utilizada en el método de los momentos (MoM). A este nuevo método se le ha denominado "Substructure Characteristic Mode method", y está basado en la implementación de los complementos Schur sobre las submatrices del operador del MoM. Este estudio permite optimizar el ancho de banda de radiación de un DRA en el mismo proceso de análisis tanto para el dieléctrico como para la alimentación, como por ejemplo una ranura. Además, este método permite comprender como se comporta la ranura en presencia del resonador dieléctrico y viceversa. Este método también puede usarse para diseñar DRA usando permitividades bajas. Esto es importante en el diseño de DRA porque la alimentación perturba el sistema y produce un cambio en las resonancias de los modos característicos. Por lo tanto, al considerar la alimentación en el análisis de modos característicos se obtienen resultados más realistas comparándolos con los obtenidos mediante un análisis convencional. Así, diseñando con el "Substructure Characteristic Mode method" se pueden extraer nuevas conclusiones sobre el diseño de DRA mediante la Teoría de Modos Característicos. / En l'última dècada, la teoria dels modes característics està sent utilitzada per molts grups d'investigació en tot el món. Este tema i el seu ús en diferents dissenys d'antenes metàl·liques està creixent molt ràpid. No obstant això, la majoria de les aplicacions s'han concentrat únicament en superfícies conductores sense cap coneixement físic sobre les seues limitacions i la seua interpretació física. Pel que fa a cossos dielèctrics, no hi ha hagut tants articles publicats com en metalls. La raó és que hi ha diferents formulacions integro- diferencials i la interpretació de les seues solucions no és tan òbvia com en cossos conductors. En esta tesi es presenta una interpretació teòrica considerant cossos conductors i dielèctrics sense pèrdues. Les conclusions d'esta tesi ens permetran comprendre millor les solucions de la Teoria de Modes Característics i les seues limitacions. Açò és important en enginyeria d'antenes. Açò és important en enginyeria d'antenes. A més, esta anàlisi permetrà desenrotllar un nou mètode per al disseny d'antenes basades en ressonadors dielèctrics, DRA. Este mètode està basat en la formulació PMCHWT i la funció de Green multicapa utilitzada en el mètode dels moments (MoM) . A este nou mètode se li ha denominat "Substructure Characteristic Mode method", i està basat en la implementació dels complements Schur sobre les submatrius de l'operador del MoM. Este estudi permet optimitzar l'amplada de banda de radiació d'un DRA en el mateix procés d'anàlisi tant per al dielèctric com per a l'alimentació, com per exemple una ranura. A més, este mètode permet comprendre com es comporta la ranura en presència del ressonador dielèctric i viceversa. Este mètode també pot usar-se per a dissenyar DRA usant baixes permitivitats. Açò és important en el disseny de DRA perquè l'alimentació pertorba el sistema i produïx un canvi en les ressonàncies dels modes característics. Per tant, al considerar l'alimentació en l'anàlisi de modes característics s'obtenen resultats més realistes comparant-los amb els obtinguts per mitjà d'una anàlisi convencional. Així, dissenyant amb el "Substructure Characteristic Mode method" es poden extraure noves conclusions sobre el disseny de DRA per mitjà de la Teoria de Modes Característics. / Bernabeu Jiménez, T. (2017). Contribution to the physical interpretation of characteristic mode resonances. Application to dielectric resonator antennas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86177 / TESIS

The subject of this diploma thesis is design a cable-supported pedestrian bridge. Three different variants of the solution were created for the design. For detailed processing, variant no.2 was chosen - a suspended bridge with a pylon in the middle of the span. The main task is the static design of the supporting structure. The model for the lengthways is created in ANSYS. The SCIA engineer was used to solve crosswise. The assessment and dimensioning was done according to the limit state principles and valid standards.

The aim of this master thesis is a design of the pedestrian bridge across the highway. The bridge is formed by a slab structure of 6 spans with lenghts from 9 to 51 m. The main spans are suspended on a V shape pylon. The deck of the span across the highway is assambled of precast segments and composite deck slab. The deck is in the lenghtways kept in the parabolic arch. The model of the construction is made in software ANSYS, the solution was done non-linear. The design and assessment are according to the europien standard.

The objective of this master's thesis is a design of suspension footbridge. The footbridge is suspended construction of stress ribbon by one span. The brick deck is supported on the edges and it is kept in a parabolic arc. The suspension cables are kept at two inclined levels. The model lengthways is implemented in the program ANSYS, by non-linear solution. The model crosswise is implemented in the program SCIA ENGINEER 2011. The design is according to relevant current standart.