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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.
81

Microlaboratórios autônomos para monitoramento de parâmetros de qualidade da água. / Autonomous microlaboratories for water quality monitoring parameters.

Rocha, Zaira Mendes da 10 November 2009 (has links)
Neste trabalho, foram desenvolvidos MicroLaboratórios Autônomos (MLA), baseados no conceito de MicrosSistemas de Análise Total (TAS), que permitem a integração das etapas associadas ao método analítico em único dispositivo. Os MLA foram fabricados utilizando a tecnologia LTCC (Low Temperature Co-fired Ceramics), que permitiu um alto grau de integração das plataformas químicas microfluídica e eletrônica, utilizando o mesmo substrato. O MLA amperométrico foi construído de forma a integrar canais, misturadores e eletrodos (auxiliar, de referência e de trabalho (sendo o último facilmente removível, tornando o dispositivo mais versátil)). Também, possui integrado em sua superfície um potenciostato, capaz de aplicar potenciais constantes e registrar com precisão correntes na faixa de nA a A. Com o equipamento, foram realizadas medições de cianeto de ferro e cloro livre confirmando a funcionalidade do MLA amperométrico. Para tal, foram testadas concentrações de K4Fe(CN)6 variando de 0,1 3 mM, apresentando faixa linear de 0,1 a 0,75 mM com coeficiente de correlação linear de 0,997 e RSD de 1,91 % (calculado para a amostra de 0,75 mM, n = 13). Cloro livre foi medido na faixa de 0,35 7,10 mM apresentando resposta linear com r2 = 0,998, o RSD obtido foi de 1,93 % (3,5 mM; n = 15). O cloro livre foi medido em amostra reais de piscinas na faixa 0,4 a 1,1 mg L-1 e os resultados foram comparados com o método DPD (Ndietil- p-fenilenodiamina) apresentando resultados similares com r2 = 0,91. O MLA fotométrico segue o mesmo princípio do amperométrico com canais, misturadores, célula de fluxo, detector, arranjo de LEDs (420, 480, 515, 565, 590, 630 e 700 nm) e eletrônica de controle integrados no mesmo substrato. O equipamento foi desenvolvido permitindo dois modos de operação: espectrofotômetro e fotômetro. No modo espectrofotométrico foi empregado na determinação qualitativa e quantitativa de diversos corantes (alaranjado de metila, azul de metileno, verde de bromocressol e vermelho de fenol). Já na opção fotométrico foi usado na determinação de fósforo reativo em águas, por meio de um sistema completamente automatizado. Neste caso, o controle de diversas válvulas e uma bomba peristáltica permitiu a implementação de procedimentos de automatização como: multicomutação, amostragem binária e parada de fluxo (stopped flow. A utilização deste sistema automatizado permitiu a comparação entre dois métodos de preparações de amostra: diluição on-line (utilizando as válvulas) e preparadas manualmente. Para ambos os casos foram analisadas duas faixas de concentrações (0,1 a 1 mg L-1 e 1,5 a 15 mg L-1). A primeira faixa apresentou-se linear para ambos os métodos de preparação de amostra, apresentando limites de detecção para fósforo reativo de 15,8 g L-1 e 14,9 g L-1. Por outro lado, foi observado que a segunda faixa de concentração não obedece à lei de Beer. Na segunda faixa, a curva analítica foi linear no intervalo de concentração de 1,5 a 7,5 mg L-1 de fósforo reativo com r2 = 0,965 e RSD de 0,43 % (7,5 mg L-1, n = 3). A frequência de medições analíticas foi de 30 determinações por hora, o que indica que a plataforma proposta pode ser utilizada em monitoramente contínuo e de tempo real. / Analysis System (uTAS) concept which allows the integration of all steps related to an analytical process in a single device. The developed MLAs were used to monitor water quality. The MLAs were fabricated using the LTCC (Low Temperature Co-fired Ceramics) technology which allows a high integration level between chemical, microfluidics and electronics platforms on the same substrate. The amperometric MLA was build in order to integrate channels, mixers and electrodes (reference, auxiliary and work) being the last one easily removable making the device even more versatile. It also has, integrated on its surface, a potentiostate capable of applying constant voltages and precisely recording currents in the range from nA to A. With this equipment, measurements were conducted for free chlorine and iron, confirming the functionality of the amperometric MLA. Concentrations from 0,1 to 3 mM of K4Fe(CN)6 were evaluated obtaining a linear range from 0,1 to 0,75 mM with a linear correlation coefficient of 0,997 and a RSD of 1,91 % (calculated for the 0,75 mM sample with n = 13). Free chlorine was evaluated in the range from 0,35 to 7,10 mM obtaining a linear response with a r2 = 0,998, the obtained RSD was 1,93 % (for 3,5 mM; n = 15). Free chlorine was also evaluated in real samples from swimming pools in the range from 0,4 to 1,1 mg·L-1, comparing the results with those obtained by the colorimetric DPD method, showing similar values with a r2 = 0,91. The photometric MLA follows the same principle of the amperometric one, with channels, mixers, flow cell, detector, LEDs array (420, 480, 515, 565, 590, 630 e 700 nm) and control electronics, integrated in the same substrate. This equipment was developed for two operation modes: spectrophotometric and photometric. The spectrophotometric mode was used for qualitative and quantitative determination of different dyes (methyl orange, methylene blue, bromocressol green and phenol red). The photometric option was used for the determination of phosphate concentration in water, by means of a fully automated system. In this case the control of several valves and a peristaltic pump allowed the implementation or automated procedures like multicommutation, binary sampling and stopped flow. The use of this automated system allowed the comparison between two methods for sample preparation: online dilution (with valves) and manual preparation. In both cases two concentration ranges were evaluated (0,1 a 1 mg L-1 and 1,5 a 15 mg L-1). The first range linear for both sample preparation methods, with detection limits of 15,8 g L-1 e 14,9 g L-1 for orthophosphate. On the other side it was observed that in the second range of concentrations it does not obey the Beers law. In the second range, the analytics curve was linear in the interval from 1,5 to 7,5 mg L-1 of orthophosphate with a r2 = 0,965 and a RSD of 0,43 % (7,5 mg L-1, n = 3). The analytical frequency was about 30 determinations per hour, which indicates a good performance of the proposed device for on-line and real time monitoring.
82

Microlaboratórios autônomos para monitoramento de parâmetros de qualidade da água. / Autonomous microlaboratories for water quality monitoring parameters.

Zaira Mendes da Rocha 10 November 2009 (has links)
Neste trabalho, foram desenvolvidos MicroLaboratórios Autônomos (MLA), baseados no conceito de MicrosSistemas de Análise Total (TAS), que permitem a integração das etapas associadas ao método analítico em único dispositivo. Os MLA foram fabricados utilizando a tecnologia LTCC (Low Temperature Co-fired Ceramics), que permitiu um alto grau de integração das plataformas químicas microfluídica e eletrônica, utilizando o mesmo substrato. O MLA amperométrico foi construído de forma a integrar canais, misturadores e eletrodos (auxiliar, de referência e de trabalho (sendo o último facilmente removível, tornando o dispositivo mais versátil)). Também, possui integrado em sua superfície um potenciostato, capaz de aplicar potenciais constantes e registrar com precisão correntes na faixa de nA a A. Com o equipamento, foram realizadas medições de cianeto de ferro e cloro livre confirmando a funcionalidade do MLA amperométrico. Para tal, foram testadas concentrações de K4Fe(CN)6 variando de 0,1 3 mM, apresentando faixa linear de 0,1 a 0,75 mM com coeficiente de correlação linear de 0,997 e RSD de 1,91 % (calculado para a amostra de 0,75 mM, n = 13). Cloro livre foi medido na faixa de 0,35 7,10 mM apresentando resposta linear com r2 = 0,998, o RSD obtido foi de 1,93 % (3,5 mM; n = 15). O cloro livre foi medido em amostra reais de piscinas na faixa 0,4 a 1,1 mg L-1 e os resultados foram comparados com o método DPD (Ndietil- p-fenilenodiamina) apresentando resultados similares com r2 = 0,91. O MLA fotométrico segue o mesmo princípio do amperométrico com canais, misturadores, célula de fluxo, detector, arranjo de LEDs (420, 480, 515, 565, 590, 630 e 700 nm) e eletrônica de controle integrados no mesmo substrato. O equipamento foi desenvolvido permitindo dois modos de operação: espectrofotômetro e fotômetro. No modo espectrofotométrico foi empregado na determinação qualitativa e quantitativa de diversos corantes (alaranjado de metila, azul de metileno, verde de bromocressol e vermelho de fenol). Já na opção fotométrico foi usado na determinação de fósforo reativo em águas, por meio de um sistema completamente automatizado. Neste caso, o controle de diversas válvulas e uma bomba peristáltica permitiu a implementação de procedimentos de automatização como: multicomutação, amostragem binária e parada de fluxo (stopped flow. A utilização deste sistema automatizado permitiu a comparação entre dois métodos de preparações de amostra: diluição on-line (utilizando as válvulas) e preparadas manualmente. Para ambos os casos foram analisadas duas faixas de concentrações (0,1 a 1 mg L-1 e 1,5 a 15 mg L-1). A primeira faixa apresentou-se linear para ambos os métodos de preparação de amostra, apresentando limites de detecção para fósforo reativo de 15,8 g L-1 e 14,9 g L-1. Por outro lado, foi observado que a segunda faixa de concentração não obedece à lei de Beer. Na segunda faixa, a curva analítica foi linear no intervalo de concentração de 1,5 a 7,5 mg L-1 de fósforo reativo com r2 = 0,965 e RSD de 0,43 % (7,5 mg L-1, n = 3). A frequência de medições analíticas foi de 30 determinações por hora, o que indica que a plataforma proposta pode ser utilizada em monitoramente contínuo e de tempo real. / Analysis System (uTAS) concept which allows the integration of all steps related to an analytical process in a single device. The developed MLAs were used to monitor water quality. The MLAs were fabricated using the LTCC (Low Temperature Co-fired Ceramics) technology which allows a high integration level between chemical, microfluidics and electronics platforms on the same substrate. The amperometric MLA was build in order to integrate channels, mixers and electrodes (reference, auxiliary and work) being the last one easily removable making the device even more versatile. It also has, integrated on its surface, a potentiostate capable of applying constant voltages and precisely recording currents in the range from nA to A. With this equipment, measurements were conducted for free chlorine and iron, confirming the functionality of the amperometric MLA. Concentrations from 0,1 to 3 mM of K4Fe(CN)6 were evaluated obtaining a linear range from 0,1 to 0,75 mM with a linear correlation coefficient of 0,997 and a RSD of 1,91 % (calculated for the 0,75 mM sample with n = 13). Free chlorine was evaluated in the range from 0,35 to 7,10 mM obtaining a linear response with a r2 = 0,998, the obtained RSD was 1,93 % (for 3,5 mM; n = 15). Free chlorine was also evaluated in real samples from swimming pools in the range from 0,4 to 1,1 mg·L-1, comparing the results with those obtained by the colorimetric DPD method, showing similar values with a r2 = 0,91. The photometric MLA follows the same principle of the amperometric one, with channels, mixers, flow cell, detector, LEDs array (420, 480, 515, 565, 590, 630 e 700 nm) and control electronics, integrated in the same substrate. This equipment was developed for two operation modes: spectrophotometric and photometric. The spectrophotometric mode was used for qualitative and quantitative determination of different dyes (methyl orange, methylene blue, bromocressol green and phenol red). The photometric option was used for the determination of phosphate concentration in water, by means of a fully automated system. In this case the control of several valves and a peristaltic pump allowed the implementation or automated procedures like multicommutation, binary sampling and stopped flow. The use of this automated system allowed the comparison between two methods for sample preparation: online dilution (with valves) and manual preparation. In both cases two concentration ranges were evaluated (0,1 a 1 mg L-1 and 1,5 a 15 mg L-1). The first range linear for both sample preparation methods, with detection limits of 15,8 g L-1 e 14,9 g L-1 for orthophosphate. On the other side it was observed that in the second range of concentrations it does not obey the Beers law. In the second range, the analytics curve was linear in the interval from 1,5 to 7,5 mg L-1 of orthophosphate with a r2 = 0,965 and a RSD of 0,43 % (7,5 mg L-1, n = 3). The analytical frequency was about 30 determinations per hour, which indicates a good performance of the proposed device for on-line and real time monitoring.
83

Mise en boitier de circuits intégrés micro-ondes en technologie LTCC

RIDA, Khodor Hussein 03 July 2013 (has links) (PDF)
This thesis concerns the introduction and development in our laboratory of a multilayer ceramic technology, called LTCC, for RF and microwave packaging. LTCC stands for Low Temperature Co-fired Ceramics. As can be understood from its name, the low temperature means that the LTCC circuit is fired below 1000 °C that allows the use of high conductivity materials such as gold and silver. The thesis work starts after the bibliographic study of RF packaging technology, with the choice of LTCC substrate and conductor materials necessary to implement LTCC technology in our laboratory. Then, the LTCC manufacturing process is put in place and validated in order to produce operational LTCC circuits. This process includes the cut of LTCC layers, via hole and cavity creation, via fill for vertical interconnecting, screen printing for horizontal patterns, stacking, lamination and finally the firing to obtain a 3D circuit. Most encountered technological problems are resolved and the fabrication steps are validated. LTCC DESIGN RULES that contain all dimensional values required for future RF packaging designers at the laboratory is elaborated. Next, after the successful establishment of LTCC technology, it is qualified up to 40 GHz using simple RF structures such as transmission lines and planar resonators. Then, a multilayer LTCC package for an MMIC oscillator functioning in the frequency band between 10.6 and 12.6 GHz is proposed, fabricated and finally measured.
84

Využití tlustých vrstev v moderní elektronice / Application of Thick Films in the Modern Electronics

Somer, Jakub January 2013 (has links)
Tato diplomová práce se zabývá technologií tlustých vrstev a jejím možným použitím pro nekonvenční aplikace. První část práce je rešeršní a zaměřuje se především na aplikace tlustovrstvé technologie v různých oblastech použití. V teoretické části práce je dále popsána technologie LTCC, včetně technologických postupů výroby. V praktické části jsou řešeny dvě aplikace v tlustovrstvé technologii. Jedná se návrh a výrobu vysokofrekvenčního filtru a optického senzoru tlaku technologií LTCC. V závěru práce jsou provedena měření a jsou zhodnoceny dosažené výsledky.
85

Termomechanická spolehlivost pájených propojení v elektronice / Termomechanical reliability soldered connections in electronic

Novotný, Václav January 2014 (has links)
The diploma thesis deals with the sphere of solder joints reliability. The narrower focus is use of lead-free solder alloy SAC305 in the production process and parameters of its reliability. The text describes the main factors, which have the influence on the reliability of solder joints under conditions of thermal cycling. These factors also relate with choice of substrates and technological processes of preparation, which are characterized and described. Another part is devoted to estimating the reliability of soldered connections and are listed the fatigue model to estimate reliability. These fatigue models are categorized based on different physical mechanisms that operate in the soldered joints during operation. Based on the comparison of different models is selected the most appropriate model and in conjunction with simulation in ANSYS is estimated reliability. For this purpose is selected soldered connection of the FR-4 substrate and ceramic substrate via SMD component. They are manufactured test kits and subjected to conditions of temperature cycling. Results obtained from experimental measurements are compared with results obtained by simulation and calculation.
86

Propojovací technologie pro 3D elektronické a mikroelektronické konstrukce / Interconnection Technologies for 3D Electronic and Microelectronic Constructions

Nicák, Michal January 2016 (has links)
The doctoral thesis is focused on research on application possibilities of soldered interconnection structures especially for the use with innovative 3D structures assembled using the LTCC ceramic materials, PVD deposited and galvanically modified pads, solid core solder balls. It consists of several main parts. Introduction is followed by theoretical survey of current situation and technologies. Thesis continues with introduction of main goals and with summary of successively performed experiments and their results. End of the work belongs to summary of results and gained knowledge.
87

Conception d'antennes miniatures intégrées pour solutions RF SiP

Jeangeorges, Mickaël 02 December 2010 (has links) (PDF)
Ce mémoire présente la conception et l'optimisation d'antennes miniatures intégrées en modules de type System in Package. L'objectif est de répondre à un besoin croissant en modules intégrés complets, comprenant tous les composants nécessaires pour apporter des fonctionnalités sans-fil aux objets communicants. Afin de remplir cet objectif, les antennes doivent satisfaire de nombreux critères, autant au niveau des performances (adaptation, bande passante, efficacité, diagramme de rayonnement) qu'au niveau des méthodes de conception (robustesse, coût, adaptation au processus de fabrication SiP, possibilité de production industrielle). L'extrême miniaturisation rend d'autant plus délicate leur mise en oeuvre qu'elle entraîne des phénomènes physiques limitant les performances. Nos travaux étudient la possibilité d'utiliser certaines techniques d'amélioration par l'ajout d'éléments structurels (éléments capacitifs, éléments parasites, fentes) et l'utilisation de circuits d'adaptation spécifiques. Diverses modifications géométriques innovantes appliquées aux structures antennaires ont également été utilisées pour obtenir des résultats satisfaisant tous les critères. Les antennes élaborées permettent à des objets communicants de dimensions variées d'opérer dans la bande de fréquences 2,4 GHz pour des applications de type WiFi ou Bluetooth. Plusieurs séries de réalisations de prototypes ont permis de valider les résultats et confirmer les phénomènes électromagnétiques mis en jeu.
88

Bandwidth enhanced antennas for mobile terminals and multilayer ceramic packages

Komulainen, M. (Mikko) 12 June 2009 (has links)
Abstract In this thesis, bandwidth (BW) enhanced antennas for mobile terminals and multilayer ceramic packages are presented. The thesis is divided into two parts. In the first part, electrically frequency-tunable mobile terminal antennas have been studied. The first three antennas presented were of a dual-band planar inverted-F type (PIFA) and were tuned to operate in frequency bands appropriate to the GSM850 (824–894 MHz), GSM900 (880–960 MHz), GSM1800 (1710–1880 MHz), GSM1900 (1850–1990 MHz) and UMTS (1920–2170 MHz) cellular telecommunication standards with RF PIN diode switches. The first antenna utilized a frequency-tuning method developed in this thesis. The method was based on an integration of the tuning circuitry into the antenna. The tuning of the second antenna was based on a switchable parasitic antenna element. By combining the two frequency-tuning approaches, a third PIFA could be switched to operate in eight frequency bands. The planar monopole antennas researched were varactor-tunable for digital television signal reception (470–702 MHz) and RF PIN diode switchable dual-band antenna for operation at four cellular bands. The key advantage of the former antenna was a compact size (0.7 cm3), while for the latter one, a tuning circuit was implemented without using separate DC wiring for controlling the switch component. The second part of the thesis is devoted to multilayer ceramic package integrated microwave antennas. In the beginning, the use of a laser micro-machined embedded air cavity was proposed to enable antenna size to impedance bandwidth (BW) trade-off for a microwave microstrip in a multilayer monolithic ceramic media. It was shown that the BW of a 10 GHz antenna fabricated on a low temperature co-fired ceramic (LTCC) substrate could be doubled with this technique. Next, the implementation of a compact surface mountable LTCC antenna package operating near 10 GHz was described. The package was composed of a BW optimized stacked patch microstrip antenna and a wide-band vertical ball grid array (BGA)-via interconnection. Along with the electrical performance optimization, an accurate circuit model describing the antenna structure was presented. Finally, the use of low-sintering temperature non-linear dielectric Barium Strontium Titanate (BST) thick films was demonstrated in a folded slot antenna operating at 3 GHz and frequency-tuned with an integrated BST varactor.
89

Studium vzájemné interakce trhlin šířících se v částicovém kompozitu s křehkou matricí za podmínek subkritického růstu / Mutual interaction of multiple cracks growing in the particulate composite with brittle matrix under conditions of sub-critical crack growth

Slávik, Ondrej January 2017 (has links)
In the first part of the submitted diploma thesis, the knowledge in the sphere of the fracture mechanics, related to the practice part of this thesis are summarized. In that the 2D parametrical numerical model of the particle composite with multiple cracks was created, using the finite elements method. Thanks to this model it is possible to find specific configurations which are showing the existance of multiple mutual interactions between these cracks, just by simple manipulation of the input data. In the calculations the influence of the residual stresses was considered which are formed during production of the material. The effect of the subcritical crack growth was taken into account as well in this thesis.
90

Termomechanická spolehlivost pájeného připojení elektronických modulů s LTCC / Thermomechanical reliability of solder connection in electronic modules with LTCC

Krajíček, Michal January 2011 (has links)
This thesis is considered about interconnect PCB with microelectronic and electronic modules and continuing on thesis MODERN CAUSES OF ASSEMBLY MICROELECTRONICS AND ELECTRONICS MODULES. This thesis includes, definition of termomechanical strain in solder joints and description of LTCC technology. Practical part includes characterization the causes of assembly with usage chip component and proposal footprint for PCBs, modules and results of temperature cycling of tested modules.

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