This thesis deals with the design and construction of a single-phase switching power supply, which is intended for direct resistive heating of iron components. The power supply is especially intended for resistive heating of horse-shoes. The supply is able to deliver an output current of up to 1500 A at a power of up to 2500 W. The first part of this work deals with the design of individual parts of the unit, the second part is focused on construction and testing of the supply and the last part contains technical documentation. The power supply was successfully tested and the required output parameters were met. However some problems do exist, especially with overheating of the output rectifier and with contacting the heated component to the output leads of the supply. These problems will be discussed in the work. The power supply can be used as an alternative solution to classic means of iron heating. The methods and ideas presented in this work can be applied in a design of a similar power supply with high output current, but most of the design rules are valid generally for the given topology.

Die Textiltechnik ermöglicht den Einsatz von rezyklierten Kohlenstofffasern in thermoplastischen Faserverbundwerkstoffen mit hohen Festigkeitsanforderungen. Das Erreichen vergleichbarer mechanischer Eigenschaften entsprechender endlosfaserverstärkter Verbundwerkstoffe wird durch die Nutzung von Stapelfaser-Hybridgarntextilien realisiert. Die Anwendung von thermoplastischen Hybridgarntextilien für die Herstellung von mehr als 100.000 Bauteilen pro Jahr erfordert jedoch eine kurze Taktzeit zur Imprägnierung und Konsolidierung des textilen Halbzeugs. Diese ist in dem derzeitigen Stand der Technik nicht gegeben, sodass hier Forschungsbedarf besteht. Die vorliegende Arbeit präsentiert eine Methode zur Reduktion der Taktzeit zur Imprägnierung und Konsolidierung komplexer Bauteilgeometrien auf Basis leitfähiger Hybridgarntextilien von derzeitig mehreren Minuten auf unter eine Minute, mit Potenzial zur weiteren Minimierung. Dies erfolgt mittels In-situ-Erwärmung im formgebenden Werkzeug unter Nutzung der Widerstandsverluste bei Stromfluss durch die leitfähigen Verstärkungsfasern. Neben der Charakterisierung und Simulation der Erwärmung im Mehrlagengewebe wird eine Parameteranalyse an generischen Probekörpern durchgeführt, um die Machbarkeit zu demonstrieren. Genauso findet eine erfolgreiche Skalierung der Technologie durch Übertragung der Ergebnisse auf eine komplexe Bauteilgeometrie anhand einer innovativen Werkzeugtechnologie statt. Am Ende der Arbeit erfolgt eine wirtschaftliche Betrachtung der kompletten Prozesskette von der einzelnen Faser, über den Hybridroving und das Mehrlagengewebe, bis zum fertigen Bauteil. Die Arbeit zeigt eine Technologie zur wirtschaftlichen Fertigung von Bauteilen aus rezyklierten Kohlenstofffasern in unter einer Minute Taktzeit. Des Weiteren bieten sich Vorteile durch die geringen Materialkosten des Hybridrovings, den hohen Grad der Automatisierung und die energetisch effiziente intrinsische Erwärmung des Halbzeugs.

Although the airbath oven is a reliable heating method for gas chromatography (GC), resistive heating is needed for higher analytical throughput and on-site chemical analysis because of size, heating rate and power requirements. In the last thirty years, a variety of resistive heating methods were developed and implemented for both benchtop and portable GC systems. Although fast heating rates and low power consumption have been achieved, losses in column efficiency and resolution, complex construction processes and difficulties experienced in recovering damaged columns have also become problematic for routine use of resistively heated columns. To solve these problems, a new resistively heated column technique, which uses metal columns and self-insulated heating wires, was developed for capillary gas chromatography. With this method, the total thermal mass was significantly less than in commercial column assemblies. Temperature-programming using resistive heating was at least 10 times faster than with a conventional oven, while only consuming 1—5% of the power that an oven would use. Cooling a column from 350 °C to 25 °C with an air fan only required 1.5 min. Losses in column efficiency and peak capacity were negligible when compared to oven heating. The major trade-off was slightly worse run-to-run retention time deviations, which were still acceptable for most GC analyses. The resistively heated column bundle is highly suitable for fast GC separations and portable GC instruments. Fabrication technologies for microelectromechanical systems (MEMS) allow miniaturization of conventional benchtop GC to portable, microfabricated GC (µGC) devices, which have great potential for on-site chemical analysis and remote sensing. The separation performance of µGC systems, however, has not been on par with conventional GC. Column efficiency, peak symmetry and resolution are often compromised by column defects and non-ideal injections. The relatively low performance of µGC devices has impeded their further commercialization and broader application. This problem can be resolved by incorporating thermal gradient GC (TGGC) into microcolumns. Negative thermal gradients reduce the on-column peak width when compared to temperature-programmed GC (TPGC) separations. This unique focusing effect can overcome many of the shortcomings inherent in µGC analyses. In this dissertation research, the separation performance of µGC columns was improved by using thermal gradient heating with simple set-ups. The analysis time was ~20% shorter for TGGC separations than for TPGC when wide injections were performed. Up to 50% reduction in peak tailing was observed for polar analytes, which significantly improved their resolution. The signal-to-noise ratios (S/N) of late-eluting peaks were increased by 3 to 4 fold. These results indicate that TGGC is a useful tool for bridging the performance gap between µGC and benchtop GC.

Submitted by FELIPE AUGUSTO DARRIBA BATTAGLIN null (darriba@bol.com.br) on 2016-08-17T23:44:40Z No. of bitstreams: 1 DIS_MEST2016_BATTAGLIN FELIPE.pdf: 6951544 bytes, checksum: 2d13cd64aaec5226e6031c18795aaca7 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-19T18:47:28Z (GMT) No. of bitstreams: 1 battaglin_fad_me_soro.pdf: 6951544 bytes, checksum: 2d13cd64aaec5226e6031c18795aaca7 (MD5) / Made available in DSpace on 2016-08-19T18:47:28Z (GMT). No. of bitstreams: 1 battaglin_fad_me_soro.pdf: 6951544 bytes, checksum: 2d13cd64aaec5226e6031c18795aaca7 (MD5) Previous issue date: 2016-07-06 / Filmes de alumina foram depositados a partir de uma nova metodologia de deposição a plasma, utilizando o pó de acetilacetonato de alumínio (AAA) como precursor. Em trabalho prévio do grupo, foi demonstrada a viabilidade do sputtering do AAA em plasmas de argônio para deposição de filmes finos. Os bons resultados obtidos estimularam o desenvolvimento do presente trabalho, visando o aperfeiçoamento da metodologia de deposição. Para isso, primeiramente foram investigados os efeitos da alteração da composição química da atmosfera do plasma, por meio da incorporação de diferentes proporções de oxigênio (O2%) ao argônio, tornando o processo um sputtering reativo. As deposições foram realizadas espalhando-se o pó do AAA no eletrodo inferior de um sistema de plasma acoplado capacitivamente. Argônio, oxigênio ou a mistura de ambos foram admitidos até a pressão de 11,0 Pa. O plasma foi gerado pela aplicação de sinal de radiofrequência (13,56 MHz, 150 W) ao eletrodo contendo o pó, mantendo-se o eletrodo superior, também utilizado como porta-amostras, aterrado. O tempo de deposição foi de 90 minutos. Investigou-se o efeito da O2%, variada de 0 a 100%, nas propriedades dos filmes. Na etapa subsequente, filmes foram depositados por sputtering reativo utilizando-se a condição considerada ótima na última etapa do trabalho (O2% = 25%) e mantendo-se as condições de pressão, potência e tempo de tratamento constantes. Todavia, ao invés de aterrar o porta-amostras, pulsos retangulares negativos (600 V, 2 kHz, 1-100% de ciclo de trabalho) foram aplicados, promovendo bombardeamento iônico durante a deposição por sputtering reativo. O efeito do ciclo de trabalho dos pulsos nas propriedades dos filmes foi avaliado. Na última etapa do trabalho, filmes foram depositados pelo sputtering reativo a partir de atmosferas contendo 25% de O2 e 75% de Ar e em condições mais energéticas que as utilizadas nos ciclos anteriores. Para tal um primeiro conjunto de amostras foi preparado mediante aquecimento resistivo do porta-amostras (410ºC) em plasma de menor pressão (4,0 Pa) que a anteriormente utilizada. O tempo de deposição foi de 28 minutos. Um segundo conjunto de amostras foi preparado associando-se bombardeamento iônico de mais alta energia, pela aplicação de pulsos de 1200 V (20% ciclo de trabalho) ao porta-amostras e também reduzindo a pressão da atmosfera de deposição para 4,0 Pa. Nesta condição, o tempo de deposição foi de 60 minutos. Comparou-se os resultados obtidos nestes experimentos aos equivalentes obtidos anteriormente. A espessura da camada foi obtida por meio de um perfilômetro e a taxa de deposição pela razão entre espessura e tempo de deposição. A composição elementar e a estrutura molecular dos filmes foram investigadas através das técnicas de espectroscopia de retroespalhamento Rutherford e de absorção no infravermelho, respectivamente. Difração de raios X foi utilizada para investigar a microestrutura dos filmes. Inspeções na morfologia e composição química das superfícies foram conduzidas associando microscopia eletrônica de varredura e espectroscopia de energia dispersiva. A rugosidade foi derivada de perfis topográficos adquiridos por perfilometria e microscopia de força atômica, enquanto a molhabilidade da superfície foi determinada através da técnica de gota séssil. De forma geral, os filmes depositados apresentaram contribuições de grupos orgânicos e de inorgânicos relacionados à alumina amorfa. O aumento da O2% afetou a cinética do plasma, proporcionando alterações na taxa de deposição (1 a 25 nm/min), rugosidade (1 a 13 nm) e redução na concentração de carbono proveniente do precursor, de 43% (O2% = 0%) para 6% (O2% = 100%). Com o aumento na O2% também foram encontradas variações na densidade dos filmes, dentro da faixa de 0,7 a 1,9 g/cm³, e tendência de queda no ângulo de contato de 53 para 17°. Por sua vez, quando o bombardeamento iônico é associado ao processo de deposição, altera-se a taxa de crescimento dos filmes (3 a 29 nm/min) e a morfologia da superfície, por meio do alívio de tensões internas e aumento da estabilidade física da estrutura resultante. A composição química não sofreu alterações, devido as condições do sputtering reativo permanecerem inalteradas nas deposições. Já a rugosidade e a molhabilidade da superfície apresentaram comportamentos condizentes com os resultados da morfologia e topografia. Quando condições mais energéticas de deposição foram empregadas, filmes óxidos com contaminações orgânicas foram obtidos para a deposição que empregou aquecimento resistivo do porta-amostras. Nesta condição, devido a redução na pressão total, mesmo com o aquecimento resistivo a taxa de deposição foi maior (~ 6 vezes) que aquela obtida sem aquecimento. Para a situação em que bombardeamento iônico de alta energia foi utilizado, estrutura e composição química similares ao do composto precursor foram obtidas. Os resultados são interpretados em termos dos processos predominantes em cada uma das metodologias empregadas. / Alumina films were deposited by a new plasma deposition method using aluminum acetylacetonate (AAA) powder as precursor. In a previous study by our group, the feasibility of AAA sputtering in argon plasmas for thin films deposition was demonstrated. The good results obtained stimulated the development of this work, aiming at the improvement of the deposition methodology. For this, the effects of modifications in the chemical composition of the plasma atmosphere were first investigated, through the use of different oxygen to argon proportions (O2%), making the process a reactive sputtering. The depositions were performed by spreading the AAA powder on the lower electrode of a capacitively coupled plasma system. Argon, oxygen or a mixture of both were admitted up to a pressure of 11.0 Pa. Application of radiofrequency power (13.56 MHz, 150 W) to the powder covered electrode generated the plasma, keeping the upper electrode, also used as a sample holder, grounded. Deposition times of 90 minutes were used. The effects of varying the oxygen proportion from 0 to 100%, on the film properties were studied. In the subsequent stage, films were deposited by reactive sputtering using the condition considered best in the last stage of the work (O2% = 25%) and keeping the pressures, power and treatment time constant. Instead of grounding the sample holder, however, negative rectangular pulses (600 V, 2 kHz, 1-100% duty cycle) were applied, promoting ion bombardment during the deposition by reactive sputtering. The influence of the pulse duty cycle on the properties of the films was evaluated. In the last study stage, films were deposited by reactive sputtering from atmospheres containing 25% O2 and 75% Ar and with more energetic conditions than those used in previous cycles. For such, a first samples set was prepared by resistive heating of the sample holder (410ºC) in a lower plasma pressure (4.0 Pa) than that previously used. The deposition time was 28 minutes. A second samples set was carried out associating ion bombardment of the highest energy, by the application of the 1200 V pulses (20% duty cycle) to the sample holder and also reducing the pressure of the deposition atmosphere to 4.0 Pa. In this condition, the deposition time was 60 minutes. The results obtained in these experiments were compared to the equivalent obtained previously. Film thickness was obtained by profilometry and the deposition rate calculated as the ratio between the thickness and deposition time. Elemental composition and molecular structure of the films were investigated using Rutherford backscattering and infrared absorption spectroscopy, respectively. X-ray diffraction was used to investigate the microstructure of the films. Surface morphology and chemical composition were studied using scanning electron microscopy and energy dispersive spectroscopy. Roughness was derived from topographic profiles acquired by profilometry and atomic force microscopy, whereas the surface wettability was determined using the sessile drop technique. In general, the deposited films showed contributions from organic and inorganic groups related to amorphous alumina. Increasing in O2% affected the plasma kinetics, providing changes in deposition rate (1 to 25 nm/min), roughness (1 to 13 nm) and reduction in the carbon concentration coming from the precursor, 43% (O2% = 0%) to 6% (O2% = 100%). With the increase in O2% it was also found variations in the films density, within the range from 0.7 to 1.9 g/cm³, and a downward trend in the contact angle of 53 to 17°. In turn, when the ion bombardment is associated with the deposition process, changes are found in the deposition rate (3 to 29 nm/min) and the surface morphology, through the internal strains relief and increased in the physical stability of resulting structure. The chemical composition did not suffer changes because the conditions of the reactive sputtering remain unchanged in the depositions. The roughness and surface wettability showed behavior consistent with the morphology and topography results. When more energetic conditions were employed, oxide films with organic contaminations were obtained for the deposition which applied the sample holder resistive heating. In this condition, due to the reduction in the total pressure, even with the resistive heating the deposition rate was higher (~ 6 times) than that obtained without heating. For the situation which high-energy ion bombardment was used, the structure and chemical composition similar to the precursor were obtained. The results are interpreted in terms of the prevailing processes in each of the methodologies applied.

Lab-on-a-Chip-Systeme sind mikrofluidische, portable Systeme mit denen bioanalytische Reaktionen und Auswertungen an kleinen Probenvolumina vor Ort durchführbar sind. In der vorliegenden Arbeit wird eine Entwurfsstrategie für das integrierte, resistive Heizen in einem solchen System auf Basis einer polymerbasierten, modularen Technologieplattform entwickelt. Dabei wird eine Modellierung als Feldmodell, die Ableitung eines reduzierten Makromodells sowie die experimentelle Untersuchung und Verifikation beschrieben. Verschiedene Ansätze für die Abbildung temperaturunabhängiger und -abhängiger elektrisch-thermischer Wandler sind berücksichtigt. Der Einflüsse von Aufbau, Widerstandsverhalten, Randbedingungen, sowie der elektrischen Ansteuerung auf die Temperatur der Biosensorfläche, in der die bioanalytische Reaktion erfolgt, werden dargelegt. / Lab on a chip systems are portable microfluidic systems which enable bioanalytical reactions and the appropriate analysis at the point of need using small sample volumes. In this publication a design strategy for integrated resistive heating in such a polymer based system is developed. The modelling comprises a field model, a derived reduced macro model and the experimental characterisation. Approaches to describe temperature dependent as well as independent electric-thermal converters are taken into account. The effects of the assembly, resistive behaviour, boundary conditions as well as the drive electronics on the temperature of the biosensor are presented.