The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole. A literature survey that summarizes the analytical calculation methods developed in earlier Swedish research is presented in the report. Different geometries with or without insulation of the central pipe have been analyzed and the effective borehole resistance for each geometry has been calculated based on the simulation results. The model has been validated against a recently performed thermal response test, and shows very good correlation with reality. The results from the simulations show that by using the annular CBHE an increase of 2-3 °C in the evaporator of the heat pump can be achieved. Calculations show that the pump work (head loss) can be reduced to 1/6 of the corresponding case with a single U-pipe. There arises a vertical temperature gradient in the bedrock when recharging and extracting heat with the annular CBHE. This means that the annular CBHE acts like a counter-flow heat exchanger which is thermally optimal. In total, the simulation result shows that the annular CBHE geometry in this thesis can increase a system's seasonal performance factor (SPF) with 10-19 % in comparison with a U-pipe BHE. This is equivalent to 10-19 % lower electrical power consumption every year.

Novel polymer-enhanced photodefined through-silicon via (TSV) and passive technologies have been demonstrated for silicon interposers to obtain compact heterogeneous computing and mixed-signal systems. These technologies include: (1) Polymer-clad TSVs with thick (~20 µm) liners to help reduce TSV losses and stress, and obtain optical TSVs in parallel for interposer-to-interposer long-distance communication; (2) Polymer-embedded vias with copper vias embedded in polymer wells to significantly reduce the TSV losses; (3) Coaxial vias in polymer wells to reduce the TSV losses with controlled impedance; (4) Antennas over polymer wells to attain a high radiation efficiency; and (5) High-Q inductors over polymer wells. Cleanroom fabrication and characterization of the technologies have been demonstrated. For the fabricated polymer-clad TSVs, resistance and synchrotron x-ray diffraction (XRD) measurements have been demonstrated. High-frequency measurements up to 170 GHz and time-domain measurements up to 10 Gbps have been demonstrated for the fabricated polymer-embedded vias. For the fabricated coaxial vias and inductors, high-frequency measurements up to 50 GHz have been demonstrated. Lastly, for the fabricated antennas, measurements in the W-band have been demonstrated.

Šiame darbe nagrinėjamos galimybės patobulinti plačiajuostės dielektrinės spektroskopijos metodus naudojant skaitmeninius ir analitinius daugelio modų dielektrinės skvarbos skaičiavimo metodus, tiriami (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 (NBT-LMT) keramikų grupės laidumo ypatumai. Nagrinėjama galimybė pritaikyti HFSS skaitmeninio modeliavimo programą dielektrinės spektroskopijos tikslams. Naudojant šią programinę įrangą, apskaičiuojama dielektrinė ir magnetinė skvarbos komplikuotiems mikrojuostelinės linijos ir dalinai užpildyto bangolaidžio matavimo grandinių atvejams. Pateikiami patobulinti kondensatoriaus koaksialinėje linijoje ir ribotų matmenų atviro galo koaksialinės linijos matematiniai modeliai. Šie modeliai patikrinami skaitmeniniu metodu. Naudojant daugiamodį kondensatoriaus modelį, atsižvelgus į magnetinio lauko pasiskirstymą koaksialinėje matavimo grandinėje, pasiūlomas būdas pamatuoti mažai bandinio magnetinei skvarbai, kai dielektrinė skvarba didelė (dešimtim ar šimtais kartų didesnė už magnetinę skvarbą). Atviro galo koaksialinei linijai siūloma keletas kalibravimo būdų, įrenginys bandiniui prispausti prie linijos. Bešvinė NBT-LMT keramika buvo tyrinėjama dielektrinės spektroskopijos metodais. Gauti rezultatai rodo, kad NBT-LMT keramikų grupėje elektriniam laidumui galioja Maerio-Neldelio taisyklė. / Šiame darbe nagrinėjamos galimybės patobulinti plačiajuostės dielektrinės spektroskopijos metodus naudojant skaitmeninius ir analitinius daugelio modų dielektrinės skvarbos skaičiavimo metodus, tiriami (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 (NBT-LMT) keramikų grupės laidumo ypatumai. Nagrinėjama galimybė pritaikyti HFSS skaitmeninio modeliavimo programą dielektrinės spektroskopijos tikslams. Naudojant šią programinę įrangą, apskaičiuojama dielektrinė ir magnetinė skvarbos komplikuotiems mikrojuostelinės linijos ir dalinai užpildyto bangolaidžio matavimo grandinių atvejams. Pateikiami patobulinti kondensatoriaus koaksialinėje linijoje ir ribotų matmenų atviro galo koaksialinės linijos matematiniai modeliai. Šie modeliai patikrinami skaitmeniniu metodu. Naudojant daugiamodį kondensatoriaus modelį, atsižvelgus į magnetinio lauko pasiskirstymą koaksialinėje matavimo grandinėje, pasiūlomas būdas pamatuoti mažai bandinio magnetinei skvarbai, kai dielektrinė skvarba didelė (dešimtim ar šimtais kartų didesnė už magnetinę skvarbą). Atviro galo koaksialinei linijai siūloma keletas kalibravimo būdų, įrenginys bandiniui prispausti prie linijos. Bešvinė NBT-LMT keramika buvo tyrinėjama dielektrinės spektroskopijos metodais. Gauti rezultatai rodo, kad NBT-LMT keramikų grupėje elektriniam laidumui galioja Maerio-Neldelio taisyklė.

Šiame darbe nagrinėjamos galimybės patobulinti plačiajuostės dielektrinės spektroskopijos metodus naudojant skaitmeninius ir analitinius daugelio modų dielektrinės skvarbos skaičiavimo metodus, tiriami (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 (NBT-LMT) keramikų grupės laidumo ypatumai. Nagrinėjama galimybė pritaikyti HFSS skaitmeninio modeliavimo programą dielektrinės spektroskopijos tikslams. Naudojant šią programinę įrangą, apskaičiuojama dielektrinė ir magnetinė skvarbos komplikuotiems mikrojuostelinės linijos ir dalinai užpildyto bangolaidžio matavimo grandinių atvejams. Pateikiami patobulinti kondensatoriaus koaksialinėje linijoje ir ribotų matmenų atviro galo koaksialinės linijos matematiniai modeliai. Šie modeliai patikrinami skaitmeniniu metodu. Naudojant daugiamodį kondensatoriaus modelį, atsižvelgus į magnetinio lauko pasiskirstymą koaksialinėje matavimo grandinėje, pasiūlomas būdas pamatuoti mažai bandinio magnetinei skvarbai, kai dielektrinė skvarba didelė (dešimtim ar šimtais kartų didesnė už magnetinę skvarbą). Atviro galo koaksialinei linijai siūloma keletas kalibravimo būdų, įrenginys bandiniui prispausti prie linijos. Bešvinė NBT-LMT keramika buvo tyrinėjama dielektrinės spektroskopijos metodais. Gauti rezultatai rodo, kad NBT-LMT keramikų grupėje elektriniam laidumui galioja Maerio-Neldelio taisyklė. / One of the basic problems in measurements of the electrical properties of materials is finding relations between measured electrical values and characteristics of the material, especially when the field distribution in the device under test with a sample inside is complex. Commercial electromagnetic simulation software was used in unconventional way to calculate materials' electrical properties. Because the software is not adopted for this task, built-in optimisation option was used. In this way dielectric and magnetic properties of materials in very complex shape were calculated. The method was tested by calculation of complex dielectric permittivity of Bi1.5ZnNb1.5O7-xF2 pyrochlore ceramics as well as by calculation of both complex dielectric permittivity and complex dielectric permeability of carbon-coated capsules of Ni embedded into polyurethane matrix from experimental results. Due to the fact that using numerical methods is time consuming, a mathematical model on mode matching approach of rectangular rod in a waveguide and a new model of multimode capacitor were developed. Models were checked by numerical methods. On a high frequency, when electric field in the sample is inhomogeneous, the magnetic field in the sample is much stronger than in the transmission line. Thus, the magnetic permeability of the sample will affect scattering parameters. Based on this circumstance, the method to measure small magnetic permeability using capacitor like in coaxial line when... [to full text]

Le travail effectué dans le cadre de cette thèse porte sur l’étude des plasmas magnétisés et nonmagnétisés produits par des structures coaxiales qui font office à la fois de propagateur d’onde et de coupleur à impédance adaptée au plasma, mais aussi de sonde d’investigation et de caractérisation de la décharge. Une attention particulière est accordée à l’efficacité de couplage entre l’onde électromagnétique et la décharge et de production d’espèces, et ce pour différentes conditions opératoires : fréquence d’excitation (352 et 2450 MHz),configuration magnétique, géométrie de l’applicateur. L’analyse quantitative et comparative présentée dans ce travail s’appuie aussi bien sur une approche expérimentale que théorique. Les modèles analytiques développés etla simulation électromagnétique réalisée permettent d’extraire à partir des mesures expérimentales, d’une partl ’impédance du plasma décorrélée de celle de la structure de propagation de l’onde, et d’autre part, l’absorption globale et locale de l’onde. Du point de vue expérimental, des techniques et méthodes appropriées ont donc été développées et mises en oeuvre comme, par exemple la méthode de changement de plan d’impédance, ou encore l’auto-interférométrie. L’étude paramétrique, menée sur un domaine de pression étendu sur plusieurs décades(10-4 – 10 Torr) et pour une gamme de puissances allant de un à plusieurs centaines de watts, a permis une investigation minutieuse du type de couplage (capacitif, inductif, résistif) qui est fortement dépendant des caractéristiques de la décharge et donc des paramètres opératoires. Leur mise en corrélation, associée à l’analyse des modes de propagation dans un plasma magnétisé, a permis de localiser avec plus de précision les zones de couplage et d’identifier les principaux mécanismes d’absorption de l’onde mis en jeu. Les principaux résultats obtenus confirment une meilleure efficacité de production d’espèces chargées à une fréquence plus élevée (2450MHz), et la présence d’une population d’électrons chauds plus conséquente ainsi qu’une extension spatiale du plasma lorsque la fréquence est plus faible (352 MHz). Comme la technologie 352 MHz à état solide est plus avantageuse du point de vue du coût des composants, comparée à 2450 MHz, elle pourrait s’avérer intéressante pour des procédés visant la production d’espèces chimiquement actives. Toutefois, le couplage, peu efficace, de type capacitif induit par la diminution de la fréquence, requiert une attention accrue au niveau de la configuration du coupleur. Pour le développement en amont des coupleurs, les résultats issus de ce travail de thèse et les modèles analytiques développés devraient constituer un outil déterminant dans la conception de sources plasma micro-onde performantes. / The work done within the framework of this thesis focuses on the study of magnetized and nonmagnetizedplasmas produced by coaxial structures that serve both as wave propagator and as plasma matchedimpedance coupler but also as investigation and characterization probe of the discharge. Special attention isgiven to the efficiency of coupling between the electromagnetic wave and the discharge and of speciesproduction, for different operating conditions: excitation frequency (352 and 2450 MHz), magnetic configurationand geometry of the applicator. Quantitative and comparative analysis presented in this work is based both on anexperimental and a theoretical approach. Developed analytical models and conducted electromagnetic simulationare set in connection with the experimental measurements in order to determine, on the one hand, the plasmaimpedance de-embedded of the wave propagation structure and, on the other hand, the global and localabsorption of the wave. From the experimental point of view, appropriate techniques and methods have thereforebeen developed and implemented such as, for example, the impedance plane shift method, or autointerferometry.The parametric study, conducted on a pressure range extended over several decades (10-4 - 10Torr) and power ratings from one to several hundred watts, led to a thorough investigation of the coupling type(capacitive, inductive, resistive ) which is highly dependent on the discharge characteristics and thus of theoperating parameters. Their correlation, combined with the analysis of propagation modes in a magnetizedplasma, has helped locate more accurately the areas of coupling and to identify the main power absorptionmechanisms involved. The main results obtained for the two frequencies confirm a better production efficiencyof charged species at a higher frequency (2450 MHz), the presence of a more substantial hot electron populationand a spatial expansion of the plasma when the frequency is low (352 MHz). As the solid state 352 MHztechnology is more advantageous compared to that at 2450 MHz from the viewpoint of the cost of thecomponents, it could be interesting for processes aiming to produce active chemical species. However itsinefficient coupling, of capacitive type induced by frequency reduction, requires an increased attention at thelevel of coupler configuration. For upstream development of couplers, the analytical models and theexperimental results obtained in this thesis should be a key tool in the design of high-performance microwaveplasma sources.

Dans les chambres de combustion des moteurs fusées cryotechniques, la pression excède la pression critique des réactifs. Les interactions moléculaires ne sont plus négligeables et le comportement du fluide n’est plus celui d’un gaz parfait. Le but de cette thèse est de développer un outil de Simulation des Grandes Echelles (SGE) pour étudier la combustion et la dynamique dans des géométries réalistes de moteur fusées. L’utilisation de l’équation d’état de Peng-Robinson, associée à une formulation thermodynamique généralisée, et des coefficients de transports appropriés permettent au code de SGE AVBP du CERFACS de simuler des systèmes réactifs à pression supercritique. Les changements thermodynamiques au sein d’AVBP nécessitent également l’adaptation des conditions limites et des schémas numériques. L’outil est validé sur une configuration mono-espèce à pression supercritique, puis sur un cas représentatif d’un injecteur coaxial de moteur-fusée. Les résultats obtenus sont en bon accord avec l’expérience et offrent des perspectives encourageantes pour des études futures, telles que des configurations multi-injecteurs ou l’analyse des instabilités de combustion haute fréquence. / In cryogenic engines combustion chambers, pressure exceeds the propellants critical pressure. Molecular interactions are generally no longer negligible and fluid behavior deviates from that of a perfect gas. The objective of this thesis is to develop a Large-Eddy Simulation (LES) tool to study combustion and dynamics in realistic geometries of rocket engines. The use of the Peng-Robinson equation of state, in conjunction with a generalized treatment of thermodynamics and appropriate transport coefficients, allows the CERFACS’ LES code AVBP to handle reactive systems at supercritical pressure. Change of the thermodynamics in AVBP necessarily leads to an adaptation of boundary conditions treatment and numerical schemes. The tool is validated on a mono-species configuration at supercritical pressure, and a reactive single coaxial injector, representative of a rocket injector. Results are in good agreement with experiments and provide encouraging perspectives for future studies, such as multi-injector configurations and high-frequency combustion instabilities.

La stabilisation et l’automatisation du vol de tout véhicule aérien nécessite la mise en oeuvre d’algorithmes de commande. La synthèse et la simulation des lois de commande reposent sur un modèle mathématique du véhicule, qui doit être de complexité et de précision appropriées. Cette thèse présente une méthodologie complète d’identification appliquée à un hélicoptère coaxialminiature. L’étude théorique de son comportement en vol permet d’établir plusieurs modèles basés sur la mécanique du vol, qui diffèrent par les phénomènes aérodynamiques pris en compte. Ils sont identifiés, comparés et validés grâce à des données de vol, mettant en évidence l’importance de certains phénomènes dans la précision du modèle. Différentes lois de commande sont alors étudiées et évaluées en simulation puis par des expérimentations sur un prototype. Les résultats obtenus sont conformes aux simulations numériques, validant ainsi l’ensemble de la démarche. / Control algorithms are at the heart of the stability and automatic flight capabilities of any aerial vehicle. Synthesis and simulation of control laws are based on a mathematicalmodel of the vehicle, which must be a trade-off between simplicity and accuracy. This work presents a complete system identification methodology applied on a miniature coaxial helicopter. Based on flight mechanics and aerodynamics, several models are built. They differ in the aerodynamic phenomena taken into account. They are identified, compared and validated thanks to flight data, highlighting important phenomena in the accuracy of the model. Several flight control strategies are then studied and evaluated through simulations and experiments with a prototype. The results are in accordance with numerical simulations, thus validating the whole approach.

Las emulsiones del tipo agua en aceite (w/o) y aceite en agua (o/w) están compuestas por una mezcla de aceite, agua, lodo y otros agentes. Se pueden encontrar en el proceso y/o en los vertidos de diferentes tipos de industrias, tales como refinerías de petróleo, plantas procesadoras de aceite de consumo, industrias farmacéuticas, industrias de alimentos, etc. El calentamiento de un material a una frecuencia de microondas depende de la frecuencia de la onda electromagnética y de las propiedades dieléctricas, así como de la acumulación de energía interna que va ligada a la profundidad de penetración del campo dentro del material. De este modo, el conocimiento preciso de las propiedades dieléctricas de los materiales es fundamental para conocer su comportamiento bajo la influencia de un campo electromagnético. El objetivo general de esta tesis es proponer métodos alternativos basados en la tecnología de microondas para monitorizar, caracterizar y/o separar emulsiones. Para ello, se determinaron los protocolos de preparación de emulsiones prototipo en el laboratorio, empleando dos fases distintas (ácido oleico y aceite mineral SAE 40), de composición similar a las encontradas en la industria. Paralelamente se ha seleccionado, montando y calibrando un sistema de medida de propiedades dieléctricas en un rango de frecuencias de 1 a 4 GHz (rango cercano a la frecuencia estándar de calentamiento f =2.45 GHz) y de esta manera se ha obtenido un amplio espectro de información del comportamiento dieléctrico de las emulsiones, que servirán para diseñar en una fase posterior aplicadores de microondas. En base a este estudio preliminar se planteó una experiencia piloto con emulsiones reales presentes en el proceso de extracción de aceite de palma africana, con el fin de determinar el efecto de las microondas en la separación y en la calidad del aceite recuperado. / Pérez Páez, R. (2009). Aplicación de microondas en el tratamiento de emulsiones del tipo agua en aceite (w/o) y aceite en agua (o/w) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/4328 / Palancia

Overall topic of presented thesis is development of methods of measurement of low impedances below 10 Ohm in a frequency range up to 1 MHz. The thesis comprises of three main parts. First part of thesis describes design of unique and simple calculable standards of resistance that are used for calibration of the bridge and as the reference standards for the calibrations. Next part of theses is focused on design of digital sampling bridge in various topologies suitable for measurement of various types of impedance standards up to frequency of 1 MHz. The thesis describes the HW components, data processing and corrections scheme allowing the designed bridge to reach expanded uncertainties (k=2) below 0.005% and 250 µrad at 1 MHz. One of the key points of the proposed corrections scheme is unique automatic linearity calibration method requiring minimal operator's effort. The theses also describes integration of Spice model of the bridge the bridge SW that allowed validation of functionality of the bridge and also analysis of uncertainty contributions related to interferences between the bridge components. The last part of the thesis shows selection of measurements of known impedances and international comparisons that proofs performance of the bridge.

This thesis deals with optimization of coaxial cavity filters. It thoroughly describes optimization method Tuning – Space Mapping (TSM) in CST Studio. It focuses on the explanation of the fine and the coarse model and their mutual link. The whole algorithm is illustrated and tested on the third-order coaxial cavity filter working in the band of 880 – 960MHz. In order to check the function of TSM, the algorithm is applied on fourth-order filter, triplet filter and quadruplet filter. Another part of the thesis focuses on the automatization of the whole optimization procedure. Macros for automatic determination of calibration constants and automatic calibration process between the coarse and the fine model are proposed and programmed in CST. The complete optimization procedure is applied on optimization of seventh-order filter with two cross couplings.