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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.
1

Návrh automatizovaného pracoviště na ohýbání dílců / Project of automatized system for bending parts production

Hirsch, Michal January 2009 (has links)
The aim of this thesis is to solve the problem from the industry, which consists of the design of workplace for bending parts using industrial robots and manipulators, appreciation and mutual comparison of the proposed alternates of solution of the problem, the choice of most of them, and the subsequent development and economic assessment. An integral part of work is also a brief summary of the issue of technology bending parts, automation and technological design.
2

Compact and Highly Sensitive Bended Microwave Liquid Sensor Based on a Metamaterial Complementary Split-Ring Resonator

Mosbah, S., Zebiri, C., Sayad, D., Elfergani, Issa T., Bouknia, M.L., Mekki, S., Zegadi, R., Palandoken, M., Rodriguez, J., Abd-Alhameed, Raed 27 March 2022 (has links)
Yes / In this paper, we present the design of a compact and highly sensitive microwave sensor based on a metamaterial complementary split-ring resonator (CSRR), for liquid characterization at microwave frequencies. The design consists of a two-port microstrip-fed rectangular patch resonating structure printed on a 20 × 28 mm2 Roger RO3035 substrate with a thickness of 0.75 mm, a relative permittivity of 3.5, and a loss tangent of 0.0015. A CSRR is etched on the ground plane for the purpose of sensor miniaturization. The investigated liquid sample is put in a capillary glass tube lying parallel to the surface of the sensor. The parallel placement of the liquid test tube makes the design twice as efficient as a normal one in terms of sensitivity and Q factor. By bending the proposed structure, further enhancements of the sensor design can be obtained. These changes result in a shift in the resonant frequency and Q factor of the sensor. Hence, we could improve the sensitivity 10-fold compared to the flat structure. Subsequently, two configurations of sensors were designed and tested using CST simulation software, validated using HFSS simulation software, and compared to structures available in the literature, obtaining good agreement. A prototype of the flat configuration was fabricated and experimentally tested. Simulation results were found to be in good agreement with the experiments. The proposed devices exhibit the advantage of exploring multiple rapid and easy measurements using different test tubes, making the measurement faster, easier, and more cost-effective; therefore, the proposed high-sensitivity sensors are ideal candidates for various sensing applications. / This work was supported by the Moore4Medical project, funded within ECSEL JU in collaboration with the EU H2020 Framework Programme (H2020/2014–2020) under grant agreement H2020-ECSEL-2019-IA-876190, and the Fundação para a Ciência e Tecnologia (ECSEL/0006/2019). This project received funding in part from the DGRSDT (Direction Générale de la Recherche Scientifique et du Développement Technologique), MESRS (Ministry of Higher Education and Scientific Research), Algeria. This work was also supported by the General Directorate of Scientific Research and Technological Development (DGRSDT)–Ministry of Higher Education and Scientific Research (MESRS), Algeria, and funded by the FCT/MEC through national funds and, when applicable, co-financed by the ERDF, under the PT2020 Partnership Agreement under the UID/EEA/50008/2020 project.
3

Conception et réalisation des standards de calibrage pour des dispositifs 3-ports à 120° / Designing and fabrication of calibration standards for 120 degrees 3-port devices

Arafat, Ousman Bechir 17 October 2016 (has links)
La caractérisation des composants hyperfréquences après leur fabrication, est généralement réalisée par la mesure de paramètres S à l’aide d’un analyseur vectoriel de réseau (VNA). La précision de mesure dépend étroitement de la qualité du calibrage de l’analyseur vectoriel, qui permet de corriger les erreurs inhérentes au système de mesure. Des composants particuliers, dits étalons ou standards, dont les paramètres sont complètement ou partiellement connus, sont mesurés lors de la procédure de calibrage afin de déterminer les erreurs systématiques du système. La réalisation d’un circulateur coplanaire (les trois ports sont à 120 degrés les uns des autres) travaillant autour de 40 GHz est l’un des axes de recherche du laboratoire depuis plusieurs années et la caractérisation des prototypes a toujours été un souci important. Le calibrage est réalisé avec un kit commercial, avec les pointes positionnées en face à face. La mesure des dispositifs CPW à accès orthogonaux ou obliques après un calibrage avec un ensemble de standards conventionnels (droits) peut engendrer des erreurs supplémentaires. L’objectif de notre travail est donc de concevoir un ensemble de standards à accès inclinés à 120 degrés permettant de calibrer l’analyseur vectoriel « 2-ports » en positionnant directement les pointes à 120 degrés. La méthode de calibrage TRL (THRU – REFLECT - LINE) a été choisie. Le travail à accomplir se résume comme suit : - faire une étude de simulation du nouveau kit de calibrage à concevoir ; - mettre en évidence l’effet des accès coudés sur les lignes de transmission des standards ; - proposer une méthode de calcul qui tient compte de ces effets lors de la procédure de calibrage ; - mesurer quelques échantillons réalisés afin de vérifier la validité de la procédure de calibrage proposée. Les résultats obtenus au cours de ce travail ont pu être validés expérimentalement et offrent de nouvelles perspectives pour la mesure des composants planaires à accès non conventionnels / Microwave components characterization after the fabrication steps is usually performed by measuring S parameters using a Vector Network Analyzer (VNA). The measurement accuracy is highly dependent on the quality of the VNA calibration, which corrects the inherent errors in the measurement system. Specific components, called standards and whose parameters are completely or partially known, are measured during the calibration procedure to determine systematic errors of the system. Fabricating a coplanar circulator (the three ports are at 120 degrees position) functioning around 40 GHz is one of the laboratory’s research areas for several years and characterization of prototypes has always been a major concern. Usually, the calibration is made with a commercial kit ; probes are in face-to-face position. Measurements of CPW devices with orthogonal or bended accesses (120 degrees in our case) after VNA calibration with conventional (straight) set of standards may generate additional errors. The aim of our work is to design a set of standards with 120_ bended accesses allowing the calibration of the “2-ports” network analyzer. Therefore, probes are directly set at 120_ position. TRL (THRU - REFLECT -LINE) calibration procedure is chosen for the standards design. The work to be done is as follows : - to make a simulation study of the new calibration kit to design ; - to determine the bended accesses effects on the standards transmission lines ; - to propose a calculation method that takes account of these effects during the calibration procedure ; - to measure some fabricated samples to verify the validity of the proposed calibration procedure. The results of this research work have been experimentally validated and offer new perspectives for measuring planar components with unconventional accesses

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