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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Développement d’une vanne d’injection de liquide pour l’analyse en ligne par chromatographie en phase gazeuse et ses applications dans le domaine du raffinage : étude du comportement et apport des colonnes monolithiques courtes pour la chromatographie en phase gazeuse haute pression / Development of a liquid injection system dedicated to on-line analysis by gas chromatography and its refining applications : study of the behavior and contribution of short monolithic columns in high pressure gas chromatography

Maniquet, Adrien 14 December 2016 (has links)
En milieu industriel, si l'analyse en ligne d'effluents gazeux à l'aide de la chromatographie en phase gazeuse est actuellement réalisée sans difficultés majeure, l'analyse des liquides reste une des principales problématiques à résoudre. En effet, comparée à une analyse réalisée au laboratoire, l'analyse en ligne d'un échantillon liquide permettrait de s'affranchir de l'étape de prélèvement et de préparation avant injection ainsi que des problèmes de contamination et de représentativité de l'échantillon. Des systèmes d'injection de liquide en ligne sont actuellement disponibles, cependant, des difficultés d'injection liées à la discrimination des analytes sont rencontrées. C'est dans ce contexte qu'une vanne dédiée à l'injection des liquides en ligne a été développée, puis validée en laboratoire, et enfin mise en œuvre sur des applications industrielles pétrolières. Un tout autre enjeu, lié entre autres à la réduction des coûts de maintenance et d'installation, ainsi qu'à la compatibilité de systèmes analytiques destinés à l'industrie et aux micro-pilotes, a orienté des développements instrumentaux vers la miniaturisation des systèmes. Un assemblage de différentes briques technologiques a ensuite été réalisé afin d'évaluer la faisabilité d'un système miniaturisé incorporant la technologie d'injection des liquides en ligne. Finalement et toujours dans ce contexte de miniaturisation, des colonnes monolithiques courtes ont été mises en œuvre en chromatographie en phase gazeuse à haute pression, au laboratoire pour commencer, puis sur des effluents industriels gazeux. Elles ont permis de réaliser des analyses très rapides avec une grande efficacité par unité de longueur tout en pouvant agir sur la sélectivité des colonnes grâce à un contrôle de leurs propriétés de surface / In industry, although on-line analysis of gaseous effluents using gas chromatography is carried out without major difficulty, the analysis of liquids remains problematic and is one of the main issues to be solved. Indeed, compared to an analysis carried out in a laboratory, the on-line analysis of a liquid sample would bypass the steps of sampling and preparation prior to injection and would avoid problems of contamination and representativeness of the sample. Systems for injecting liquids on-line are currently available; however, difficulties are encountered, due to the discrimination of analytes. It is in this context that a valve dedicated to the on-line injection of liquids was developed, validated under laboratory conditions and finally implemented in the oil industry. Another issue, related, amongst other things, to the reduction of maintenance and installation costs, as well as to the compatibility of analytical systems for industry and for micro-pilots, steered instrumental developments towards the miniaturization of systems. Different technological bricks were therefore brought together to assess the feasibility of a miniaturized system involving the technology for on-line injection of liquid. Finally, and still in the context of miniaturization, short monolithic columns were implemented in gaseous phase chromatography at high pressure, first in the laboratory and then on industrial gas effluents. They allowed very fast analyses to be performed which had greater efficiency per unit of length while still being able to act on the selectivity of the columns thanks to the control of their surface properties
92

Conception d'antennes souples et de conducteurs magnétiques artificiels en bande UHF / Design of flexible antennas and of artificial magnetic corductors in UHF band

Presse, Anthony 08 December 2015 (has links)
L'invention de l'antenne fût à la base de la création des communications sans fil à l'orée du XXe siècle. A l'origine des objets métalliques destinés à transmettre et recevoir des ondes électromagnétiques, les antennes n'ont cessé de se complexifier pour satisfaire l'impressionnant développement des communications sans fil. C'est dans ce contexte qu'est né le concept d'antenne « wearable » il y a moins de deux décennies ouvrant un nouveau champ de recherche sur les antennes souples. C'est dans ce cadre que ce travail de thèse se consacre à la conception d’antennes souples en bande UHF.Une première étude a permis de concevoir une antenne Vivaldi antipodale [150 - 900 MHz] souple pour la Section Technique de l'Armée de Terre. Six de ces antennes sont destinées à être placées sous un ballon gonflé à l'hélium pour réceptionner des signaux RF.Une seconde étude est effectuée en collaboration avec la société Syrlinks et le CNES. L'objectif du projet est de concevoir des antennes souples pour le suivi de personnes avec le système ARGOS (401 et 466 MHz). La solution retenue est une PIFA planaire de largeur inférieure à lambda/3. Elle a l'avantage d'être fine et légère. Le matériau souple employé est un caoutchouc silicone sélectionné parmi plusieurs matériaux souples grâce à des caractérisations diélectriques. Cependant, le problème de cette antenne est qu'elle possède un rayonnement quasi-omnidirectionnel. Etant donné qu'il n'était pas envisageable d'utiliser un plan réflecteur métallique pour des raisons de dimensions, il a été décidé de concevoir un conducteur magnétique artificiel (CMA) souple. Toutefois, la conception de CMA dans le bas de la bande UHF se heurte à des difficultés de miniaturisation. Pour contourner ce problème, il a été développé deux concepts de CMA à cellules unitaires de faibles dimensions devant la longueur d'onde. La première solution utilise des capacités interdigitées et la seconde une structure double couche. Pour ces deux concepts, un modèle circuit est proposé et validé par des mesures expérimentales. Les mesures de l'association CMA - antenne montrent une bande passante suffisante pour des applications ARGOS et un rayonnement majoritairement dirigée dans la direction opposé à celle du CMA. / The invention of antennas was the base of wireless communications appearance at the dawn of the twentieth century. Originally metal objects for transmitting and receiving electromagnetic waves, antennas have steadily become more complex to meet the impressive development of wireless communications. It is in this context that the concept of wearable antennas was born less than two decades ago opening a new field of research namely flexible antennas. It is in this framework that this thesis is dedicated to the design of flexible antennas for UHF band.A first study enabled the design of a flexible antipodal Vivaldi antenna [150-900 MHz] for Technical Section of the Army. Six of these antennas are intended to be placed under a balloon inflated with helium for receiving RF signals.A second study was conducted in collaboration with the company Syrlinks and CNES. The objective of the project is to design flexible antennas for tracking people with ARGOS system (401 and 466 MHz). The selected solution is a planar PIFA which width is smaller than lambda/3. This antenna has the advantage of being thin and light. The flexible material used is a silicone rubber and it was selected among several others due to some dielectric characterizations. However, the drawback of this antenna is that it has a quasi-omnidirectional radiation pattern. Since it was not possible to use a reflector metal plane due to size constraints, it was decided to design a flexible artificial magnetic conductor (AMC). However, the design of AMCs in the lower UHF band is challenged with the miniaturization difficulties. Two concepts of small size (compared to the wavelength) AMCs unit cells were developed to work around this problem. The first solution uses interdigitated capacitors and the second a double layer structure. For these two concepts, a circuit model is proposed and validated by experimental measurements. The measurement of the AMC associated antenna demonstrates a bandwidth sufficient for ARGOS applications and a radiation pattern mostly directed in the direction opposite to that of the AMC.
93

Conception d'antennes miniatures intégrées à leur support pour applications en télémédecine mobile / Design of small antenna embedded to their support for applications in telemedicine

Hamouda, Hafedh 01 October 2014 (has links)
La télémédecine et plus particulièrement la télémédecine mobile semble représenter l’avenir en termes de soins médicaux. Ce concept nécessite cependant pour sa viabilité, de disposer d’éléments rayonnants miniatures, fortement efficaces, et capables de communiquer sur plusieurs bandes. Ce mémoire présente la méthodologie de conception et l’optimisation d’antennes miniatures intégrées, dédiées à un dispositif spécifique permettant de réaliser une liaison radiofréquence entre un implant médical et le téléphone portable d’un patient. Cependant, la miniaturisation des antennes, éléments clés de ce concept, s’accompagne généralement d’une dégradation de son efficacité et de sa bande passante, ce qui rend délicat leur mise en œuvre sur au moins deux des points essentiels recherchés. La conception de ce type d'antennes nécessite donc une analyse très fine des phénomènes physiques mis en jeu dont notamment la limite théorique en termes de performances que l'on peut atteindre pour une antenne circonscrite à un volume donné. De plus, ces performances radioélectriques sont fortement dépendantes de l'environnement dans lequel est placée l’antenne. Par conséquent, l'influence de chaque partie constituant cet environnement doit être prise en compte lors de l'intégration, ce que nous décrivons également dans ce manuscrit à travers différentes solutions d’éléments rayonnants. / This thesis presents the design and the optimization of miniature antennas integrated in specific devices dedicated to ensure communications between medical implants and a mobile phone in the context of telemedicine applications. However, the miniaturization of antennas necessarily implies a degradation of efficiency and bandwidth, which makes it difficult for implementation. Then, the design of electrically small antennas requires a very good understanding of the physical phenomena such as the theoretical limits of performance in terms of bandwidth and efficiency that can be expected for a radiating element with given dimensions. Furthermore, the performance of an electrically small antenna is also highly dependent on the environment in which it is mounted. Therefore, its interaction with each part of its close environment was highlighted and analyzed.
94

Integrovaný zásuvkový modul / Smart modul integrated in power plug

Rusz, Martin January 2020 (has links)
The aim of this work is focus on Powerline Communication technology and select a suitable type of broadband integrated circuit for the integration of a broadband communication module into an electrical installation box. In the introduction of this work, the Powerline Communication technology, the principle of communication, individual types of technology, factors influencing the quality of transmission, current possibilities and setting goals necessary for the design of the module are analyzed in detail. The result is a miniaturized functional prototype of a fully integrated broadband PLC modem in a wiring box.
95

Měnič pro BLDC motor / BLDC motor controller

Němec, Petr January 2021 (has links)
The goal of this Master thesis is to design a power convertor for BLDC motor 48V/2kW. Emphasis is placed on the small dimensions of the final printed circuit board. Therefore, power SMD transistors STL135N8F7AG are used in small packages PowerFlat 5x6. To reduce area of the PCB, electrolytic capacitors are mounted on a separate board, which is located above the main PCB. Small high-capacity 22F/100V ceramic capacitors are used in the DC-LINK as well. They are located as close as possible to the power SMD tranzistors. Control logic will be provided by microprocesor STM32G474RE. High resolution timer HRTIM1 is used. The first part of this thesis is devoted to the brief description of BLDC motor construction and driving. Next parts are focused on the design itself.
96

Entwicklung eines hybrid-integrierten Gitterspektrometers basierend auf einem mikro-opto-elektro-mechanischen Bauelement

Pügner, Tino 23 November 2015 (has links)
The subject of this thesis is the development of a hybrid-integrated scanning grating spectrometer based on a micro-opto-electro-mechanical device or a micro-opto-electromechanical system, respectively. Features of spectral measurement system to be emphasized are a miniaturized construction with the volume of about a sugar cube, a corresponding low mass and low power consumption. In contrast to comparable and currently available spectroscopic instruments with compact physical dimensions, the system offers advantages in terms of enhanced mobility, portability, energy efficency, feasibility for on-site analysis and sensor integration. Miniaturized spectroscopes can help to address new areas of application as well as improve already existing applications. Food analysis, medical care, environmental monitoring, qualtiy inspection, process control, generation of bioenergy as well as safety and security tasks are exemplary fields of application. Within these areas, organic compounds ubiquitously to our everyday life play an important role. The near-infrared spectral band, that is the measurement range of the hybrid-integrated grating spectrometer, is well suited for the detection as well as the qualitative and quantitative analysis of organic compounds. The system follows the construction of a Czerny-Turner grating monochromator that is characterized by a rotatable mounted diffraction grating as well as separated optics for collimation and refocusing. By the rotation of the dispersive element, the spectrum is scanned across the fixed detector and sampled time-discretely. In the case of the hybrid-integrated spectrometer, the grating is part of a micro-opto-mechanical system, with the size of about 50 mm², developed at the Fraunhofer IPMS. Additionally to the grating, the corresponding driving mechanism, the position detection for the deflection angle and two optical slits are part of this device, as well. Integrating several functional components into one structural element is the main strategy of the construction process and is applied to all remaining features. A potentioally serial manufacturing is taken into account by the assembly and joining technology involved. Apart from the theoretical basics, the state of the art, the system specifications as well as the constructive and experimental results, a major part of this thesis is concerned with the technological and constructive boundary conditions, an analytical system description and the discussion of the solution space of this class of spectroscopic instruments. / Das Thema der vorliegenden Arbeit ist die Entwicklung eines hybrid-integrierten Gitterspektrometers basierend auf einem mikro-opto-elektro-mechanischen Bauelement. Auszeichnen soll sich das spektrale Messsystem durch einen miniaturisierten Aufbau mit dem Volumen eines Stück Würfelzuckers, einem dementsprechend geringen Gewicht und einer niedrigen Leistungsaufnahme. Im Vergleich zu bereits verfügbaren kompakten Spektralapparaten gleicher Funktionsweise ergeben sich Vorteile hinsichtlich Mobilität, Portabilität, Energieeffizienz, Anwendbarkeit in der Vor-Ort-Analytik und Sensorintegration. Mit miniaturisierten Spektrometern lassen sich neue Anwendungsgebiete adressieren und für bestehende Applikation bislang ungenutzte Entwicklungspotenziale erschließen. Exemplarische Einsatzfelder sind die Lebensmittelanalytik, Medizin- und Umweltmesstechnik, Qualitäts- und Prozesskontrolle, Bioenergiegewinnung sowie Sicherheitsanwendungen. In diesen Gebieten spielen die in unserem Alltag oft vorkommenden organischen Verbindungen eine wichtige Rolle. Zu ihrer qualitativen und quantitativen Analyse ist insbesondere der nahinfrarote Spektralbereich geeignet, in welchem das hybrid-integrierte Gitterspektrometer messen soll. Der Aufbau des Systems entspricht einem Czerny-Turner-Gittermonochromator, der durch ein drehbar gelagertes Beugungsgitter sowie eine getrennte Kollimations- und Refokussieroptik charakterisiert wird. Durch die Drehung des dispersiven Elementes verschiebt sich das Spektrum über einen ortsfesten Detektor, der die zeitdiskrete Abtastung durchführt. Im miniaturisierten Spektrometer ist das Gitter Teil eines am Fraunhofer IPMS hergestellten mikro-opto-elektro-mechanischen Bauelementes mit einer Fläche von nur 50 mm². In dieser Komponente sind neben dem dispersiven Element auch dessen Antrieb, die Positionsdetektion zum Bestimmen der Gitterauslenkung und zwei optische Spalte zusammengefasst. Die Strategie, mehrere Funktionskomponenten über geeignete Mikrofertigungstechniken in ein Bauteil zu integrieren, wird auch auf alle anderen Systembestandteile angewendet. Die Aufbau- und Verbindungstechniken zum Justieren und Montieren der komplexen Bauelemente berücksichtigt eine potenzielle Serienfertigung. Neben den theoretischen Grundlagen, dem Stand der Technik, den Systemspezifikationen sowie den konstruktiven und experimentellen Resultaten befasst sich die Arbeit eingehend mit technologischen und konstruktiven Randbedingungen, einer analytischen Systembeschreibung und der Behandlung des Lösungsraumes für diese Klasse von Spektralapparaten.
97

Development of a Compact Drive System for Total Artificial Heart / Utveckling av en kompakt drivenhet för ett totalt artificiellt hjärta

Bakhtiari, Hossin January 2023 (has links)
Over eight decades of research into total artificial hearts (TAHs) has significantly contributed  to saving end-stage heart failure patients. However, at the current stage of development TAHs have several limitations, one of them being their bulkiness. Hence this thesis, with the goal to evaluate the right pump of the TAH developed by Scandinavian Real Heart and propose a compact right drive system without consuming significantly more power than the initial system. In order to do this, the requirements for the right drive systems are evaluated and defined. These requirements are then used to develop a methodology, including a MatLab simulation, for examining and selecting motors for the drive unit of the TAH. Subsequently, the methodology and the simulation are used to identify and assess over 200 motors, as well as select 3 motors for real-world experimental analysis. The suggested motors and the initial motor are then tested in a mock circulatory loop to investigate the performance characteristics and power consumption of the motors. This is done to select the final motor for the right drive unit, as well as verify and validate the created simulation. Based on careful analysis of the mathematical models used in the simulation and presented experimental data, the simulation was accepted to be verified. However, the support for validation of the simulation was lacking, as conflicting outcome for some cases were observed between the simulation and experimental data. Furthermore, given the empirical evidence, a brushless dc motor for the right drive unit and its implementation was proposed. The proposed motor has 11% reduction in size, 20% reduction in power consumption and 34% reduction in weight compared to the initial motor. Therefore, a drive unit with the suggested motor can have a significant impact on the right pump, and potentially even the left pump. Furthermore, the utilisation of the developed simulation can ultimately result in efficient and cost-effective motor selection and provide valuable contribution to the field of drive system development for TAHs. / Över åtta decennier av forskning om totala artificiella hjärtan (TAH) har omfattande bidragit till att rädda patienters liv med kronisk hjärtsvikt. Dessvärre har TAH flera begränsningar i det nuvarande stadiet i utveckling där storleken är ett problem. Därav denna avhandling, med målet att utvärdera den högra pumpen av en TAH utvecklad av Scandinavian Real Heart, för att föreslå ett mer kompakt höger drivsystem utan att det ska förbruka väsentlig mängd mer energi än det ursprungliga systemet. För att åstadkomma detta, har de fysiologiska krav för den högra pumpen analyserats och utifrån den utförda analysen nya krav för drivsystemet har formulerats. Dessa krav har sedan lagt grunden till utveckling av en metodik, inklusive en MatLab-simulering, för att undersöka och välja motorer för drivsystemet av en TAH. Metodiken i samband med simuleringen har använts för att identifiera och bedöma över 200 motorer. Av dessa motorer har tre motorer valts för experimentell utvärdering. I den experimentella utvärderingen, prestandaegenskaper och effektförbrukning av samtliga valda motorer och den ursprungliga motorn har utvärderats i ett konstgjort cirkulationssystem. Syftet med den experimentella utvärderingen är att komma fram till en slutmotor, samt verifiera och validera den utvecklade simuleringen. Baserad på noggrann analys av de använda matematiska modeller i simuleringen och det presenterade experimentella data, ansågs simuleringen vara verifierad. Däremot saknades stöd för validering av simuleringen, på grund av en del motsägande utfall mellan simulering och experimentell data. Därutöver, utifrån den empiriska evidensen föreslogs en borstlös likströmsmotor och dess implementering för det högra drivsystemet. Den föreslagna motorn är 11% mindre i storlek, har 20% lägre effektförbrukning och väger 34% mindre än den ursprungliga motorn. Därför kan en drivenhet med den föreslagna motorn ha en betydande inverkan på den högra pumpen, och potentiellt även den vänstra. Dessutom kan den utvecklade simuleringen användas för att göra urval av motorer för TAH på ett produktivt samt kostnadseffektivt sätt och därmed bidra till framtida utvecklingar av drivenheter för TAH.
98

Novel Metamaterial Blueprints and Elements for Electromagnetic Applications

Odabasi, Hayrettin 08 August 2013 (has links)
No description available.
99

Functional Design Employing Miniaturized Electronics with Wireless Signal Provision to a Smartphone for a Strain-Based Measuring System for Ski Poles

Hentschel, Uwe, Steinbild, Philip Johannes, Dannemann, Martin, Schwaar, Andree, Modler, Niels, Schürer, Axel 03 May 2023 (has links)
The individual monitoring of cross-country skiers’ technique-related parameters is crucial to identifying possible athlete-individual deficits that need to be corrected in order to optimize the athlete’s performance in competition. To be able to record relevant biomechanical parameters during training in the field, the development of measuring systems exploiting the athlete’s full potential is the key. Known mobile monitoring systems for measuring forces on ski poles use comparably heavy uniaxial load cells mounted on the pole with a data logger also attached to the pole or carried by the athlete. Measurements that are more accurate can be acquired using wire-based systems. However, wire-based systems are highly immobile and only usable when the athletes undergo a stationary test, e.g., on a treadmill. This paper focuses on the functional design of a measuring system using specialized, miniaturized electronics for acquiring data from strain sensors. These data are then used to determine the technique-related parameters pole force and angle of bend. The functional design is also capable of transmitting the acquired data wirelessly via Bluetooth to a smartphone that runs a proprietary app. This approach is advantageous regarding mass, dynamic behavior, analyzing functionality, and signal processing compared to the state of the art.
100

Masking Moments : The Transitions of Bodies and Beings in Late Iron Age Scandinavia

Back Danielsson, Ing-Marie January 2007 (has links)
This thesis explores bodily representations in Late Iron Age Scandinavia (400–1050 AD). Non-human bodies, such as gold foil figures, and human bodies are analysed. The work starts with an examination and deconstruction of the sex/gender categories to the effect that they are considered to be of minor value for the purposes of the thesis. Three analytical concepts – masks, miniature, and metaphor – are deployed in order to interpret how and why the chosen bodies worked within their prehistoric contexts. The manipulations the figures sometimes have undergone are referred to as masking practices, discussed in Part One. It is shown that masks work and are powerful by being paradoxical; that they are vehicles for communication; and that they are, in effect, transitional objects bridging gaps that arise in continuity as a result of events such as symbolic or actual deaths. In Part Two miniaturization is discussed. Miniaturization contributes to making worlds intelligible, negotiable and communicative. Bodies in miniatures in comparison to other miniature objects are particularly potent. Taking gold foil figures under special scrutiny, it is claimed that gold, its allusions as well as its inherent properties conveyed numinosity. Consequently gold foil figures, regardless of the context, must be understood as extremely forceful agents. Part Three examines metaphorical thinking and how human and animal body parts were used in pro-creational acts, resulting in the birth of persons. However, these need not have been human, but could have been the outcomes of turning a deceased into an ancestor, iron into a steel sword, or clay into a ceramic urn, hence expanding and transforming the members of the family/household. Thus, bone in certain contexts acted as a transitional object or as a generative substance. It is concluded that the bodies of research are connected to transitions, and that the theme of transformation was one fundamental characteristic of the societies of study.

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