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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 11 to 17 of 17 (0.117 seconds)| 11 |
Ortsaufgelöste Untersuchung massengedruckter Polymersolarzellen auf flexiblem Substrat: Ortsaufgelöste Untersuchung massengedruckter Polymersolarzellenauf flexiblem SubstratZillger, Tino 16 December 2015 (has links)
Gegenstand der vorliegenden Arbeit ist die ortsaufgelöste Untersuchung der Schichtdicke und der elektrischen Eigenschaften von Funktionsschichten in gedruckten Polymersolarzellen. Die massendrucktechnische Realisierung der großflächigen Polymersolarzellen mit dem Schichtaufbau Zink/ZnO/P3HT:PCBM/PEDOT:PSS erfolgt im Tief- und Siebdruckverfahren auf einem papierbasierten Bedruckstoff. Die gedruckten Funktionsschichten werden mit verschieden optischen und elektrischen Messverfahren charakterisiert und die Eignung der Verfahren wird diskutiert. Abschließend wird die gesamte Polymersolarzelle mit einer Kombination aus spektraler und elektrischer Messung positionsgenau untersucht. Dadurch kann ein Zusammenhang zwischen den Solarzelleneigenschaften und den ortsaufgelösten Messwerten aufgezeigt werden. / The aim of this work is the space-resolved investigation of the layer thickness and the electrical properties of functional layers in printed polymer solar cells. The realization of the large-area polymer solar cells with a layer structure of zinc/ZnO/P3HT:PCBM/PEDOT:PSS occurs by gravure and screen printing on a paper-based substrate. The printed functional layers are characterized by different optical and electrical measurement methods and the suitability of these methods is discussed. Finally, the complete polymer solar cell is examined dependent on a position by using a combination of spectral and electrical measurement techniques. With this analysis a correlation between the solar cell characteristics and the space-resolved measurements can be shown.
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Fatigue Testing of Human Flexor Tendons Using a Customized 3D-Printed Clamping SystemScholze, Mario, Safavi, Sarah, Ramezani, Maziar, Ondruschka, Benjamin, Hammer, Niels 06 December 2023 (has links)
Improved surgical procedures and implant developments for ligament or tendon repair
require an in-depth understanding of tissue load-deformation and fatigue properties. Cyclic testing
will provide crucial information on the behavior of these materials under reoccurring loads and
on fatigue strength. Sparse data are available describing soft tissue behavior under cyclic loading.
To examine fatigue strength, a new technology was trialed deploying 3D-printing to facilitate and
standardize cyclic tests aiming to determine tendon fatigue behavior. Cadaveric flexor digitorum
tendons were harvested and mounted for tensile testing with no tapering being made, using 3Dprinted clamps and holder arms, while ensuring a consistent testing length. Loads ranging between
200 to 510 N were applied at a frequency of 4 Hz, and cycles to failure ranged between 8 and >260,000.
S–N curves (Woehler curves) were generated based on the peak stresses and cycles to failure. Power
regression yielded a combined coefficient of determination of stress and cycles to failure of R
2 = 0.65,
while the individual coefficients for tissues of single donors ranged between R
2 = 0.54 and R
2 = 0.88.
The here-presented results demonstrate that S–N curves of human tendons can be obtained using a
standardized setting deploying 3D-printing technology
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Integration gedruckter Elektronik in Kunststoffe durch Folienhinterspritzen / Integration of Printed Electronic Devices into Plastic Components by Film Insert MoldingWeigelt, Karin 10 February 2014 (has links) (PDF)
Ausgehend von der Anwendung von Folienhinterspritzprozessen für dekorative Zwecke wurde deren Nutzung für die Integration elektronischer Strukturen in Kunststoffbauteile untersucht. Die Herstellung der elektronischen Bauelemente erfolgte mittels verschiedener Druckverfahren mit elektrisch leitfähigen und dielektrischen Materialien auf Polycarbonatfolien. Im Fokus standen zum einen kapazitiv auslesbare Speicherstrukturen und zum anderen Elektrolumineszenzleuchten. Nach dem Druck wurden die bedruckten Folien z. T. verformt und hinterspritzt. In der Arbeit wird auf die Auswirkungen der Verform- und Hinterspritzprozesse eingegangen. Schwerpunktmäßig wird die elektronische bzw. optische Funktionalität der Bauelemente, die Beeinflussung durch Klimaveränderungen und die Haftfestigkeit der Folien betrachtet. Im Ergebnis konnten erstmals die Realisierbarkeit hinterspritzter elektronischer Bauelemente nachgewiesen sowie verschiedene Einflussfaktoren auf deren Funktionalität identifiziert werden. / Based on the application of film insert molding for graphic purposes, the utilization of this process for the integration of electronic devices into plastic components was examined. The manufacturing of the electronic devices was realized by applying electrical conductive and dielectric inks on polycarbonate foil by various printing processes. Capacitive data storage patterns and electroluminescent lamps are the main applications. The production sequence included the printing process, forming of the foil where required and back injection molding. The impact of forming and film insert molding was investigated. The electronic and/or optical functionality of the devices, the influence of ambient conditions like temperature or humidity and the adhesion strength of the foils were in the focus of the evaluation. As a result, the feasibility of film insert molded electronic devices could be verified and various impact factors could be identified for the first time.
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Druckprozesse als gezielte und innovative Fertigungsmethode von katalytischen BrennstoffzellenschichtenWillert, Andreas, Meuser, Carmen, Mitra, Kalyan Y., Baumann, Reinhard R., Zichner, Ralf 25 November 2019 (has links)
Ein bedeutender Punkt in der Brennstoffzellentechnologie ist der Einsatz von platinhaltigen Elektroden, welche die Brennstoffzellentechnologie zu einer teuren Technologie macht. Zum jetzigen Zeitpunkt werden die katalytischen Schichten in großen Maßstäben als Endlos-Elektroden produziert, was dazu führt, dass die einzelnen Elektroden für die Stacks ausgeschnitten und hierbei viel nicht genutztes Elektrodenmaterial, sprich Abfall entsteht. Dieser kann später recycelt werden, jedoch ist eine 100 %ige Rückgewinnung der eingesetzten Rohstoffe nicht möglich.
Die Drucktechnik bietet eine Möglichkeit diese Entstehung von Abfall zu vermeiden. Mittels der verschiedenen Drucktechnologien, wie z. B. Inkjet-, Tief- und Siebdruck ist es möglich Elektroden mit gezielten Geometrien zu fertigen, sprich die Elektrodenschichten werden genau an die Erfordernisse angepasst. Der Aufbau von Multilagen ist präzise möglich und es können MEA´s (Membran-Electrode Assembly) mit scharfen, klar abgegrenzten Kanten erstellt werden.
In diesem Paper werden Ergebnisse der Inkjet- und Tiefdrucktechnologie vorgestellt, sowie deren Charakterisierung. Da bereits kleinste Unregelmäßigkeiten in den Elektroden zu einem Ausfall des Systems führen können, werden die katalytischen Schichten mittels Oberflächenprofilometer (Veeko Dektak 150) auf ihre Homogenität untersucht. Darüber hinaus werden die Leitfähigkeiten (SÜSS Microtec PM5 Probe System) und die Haftung der gedruckten Schichten in Abhängigkeit von der Drucktechnologie betrachtet. / An important point in fuel cell technology is the use of platinum-containing electrodes, which makes fuel cell technology an expensive technology. At present, the catalytic layers are produced on a large scale as continuous electrodes, which results in the individual electrodes being cut out for the stacks, resulting in a lot of unused electrode material, i.e. waste. This can be recycled later, but 100 % recovery of the raw materials used is not possible.
The printing technology offers a possibility to avoid this generation of waste. Using the various printing technologies, such as inkjet, gravure, and screen printing, it is possible to produce electrodes with specific geometries, i.e. the electrode layers are precisely adapted to the requirements. The construction of multilayers is precisely possible and MEA's (Membrane Electrode Assembly) with sharp, clearly defined edges can be created.
This paper presents the results of inkjet and gravure printing technology and their characterization. Since even the smallest irregularities in the electrodes can lead to system failure, the homogeneity of the catalytic layers is examined using a surface profilometer (Veeko Dektak 150). In addition, the conductivities (SUSS Microtec PM5 Probe System) and the adhesion of the printed layers will be examined as a function of the printing technology.
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All-inkjet-printed thin-film transistors: manufacturing process reliability by root cause analysisSowade, Enrico, Ramon, Eloi, Mitra, Kalyan Yoti, Martínez-Domingo, Carme, Pedró, Marta, Pallarès, Jofre, Loffredo, Fausta, Villani, Fulvia, Gomes, Henrique L., Terés, Lluís, Baumann, Reinhard R. 10 October 2016 (has links)
We report on the detailed electrical investigation of all-inkjet-printed thin-film transistor (TFT) arrays focusing on TFT failures and their origins. The TFT arrays were manufactured on flexible polymer substrates in ambient condition without the need for cleanroom environment or inert atmosphere and at a maximum temperature of 150 °C. Alternative manufacturing processes for electronic devices such as inkjet printing suffer from lower accuracy compared to traditional microelectronic manufacturing methods. Furthermore, usually printing methods do not allow the manufacturing of electronic devices with high yield (high number of functional devices). In general, the manufacturing yield is much lower compared to the established conventional manufacturing methods based on lithography. Thus, the focus of this contribution is set on a comprehensive analysis of defective TFTs printed by inkjet technology. Based on root cause analysis, we present the defects by developing failure categories and discuss the reasons for the defects. This procedure identifies failure origins and allows the optimization of the manufacturing resulting finally to a yield improvement.
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Development of a Mechatronics Instrument Assisted Soft Tissue Mobilization (IASTM) Device to Quantify Force and Orientation AnglesAlotaibi, Ahmed Mohammed 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Instrument assisted soft tissue mobilization (IASTM) is a form of massage using rigid manufactured or cast devices. The delivered force, which is a critical parameter in massage during IASTM, has not been measured or standardized for most clinical practices. In addition to the force, the angle of treatment and frequency play an important role during IASTM. As a result, there is a strong need to characterize the delivered force to a patient, angle of treatment, and stroke frequency. This thesis proposes two novel mechatronic designs for a specific instrument from Graston Technique(Model GT3), which is a frequently used tool to clinically deliver localize pressure to the soft tissue. The first design is based on compression load cells, where 4-load cells are used to measure the force components in three-dimensional space. The second design uses a 3D load cell, which can measure all three force components force simultaneously. Both designs are implemented with IMUduino microcontroller chips which can also measure tool orientation angles and provide computed stroke frequency. Both designs, which were created using Creo CAD platform, were also analyzed thorough strength and integrity using the finite element analysis package ANSYS. Once the static analysis was completed, a dynamic model was created for the first design to simulate IASTM practice using the GT-3 tool. The deformation and stress on skin were measured after applying force with the GT-3 tool. Additionally, the relationship between skin stress and the load cell measurements has been investigated. The second design of the mechatronic IASTM tool was validated for force measurements using an electronic plate scale that provided the baseline force values to compare with the applied force values measured by the tool. The load cell measurements and the scale readings were found to be in agreement within the expected degree of accuracy. The stroke frequency was computed using the force data and determining the peaks during force application. The orientation angles were obtained from the built-in sensors in the microchip.
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Integration gedruckter Elektronik in Kunststoffe durch FolienhinterspritzenWeigelt, Karin 29 May 2013 (has links)
Ausgehend von der Anwendung von Folienhinterspritzprozessen für dekorative Zwecke wurde deren Nutzung für die Integration elektronischer Strukturen in Kunststoffbauteile untersucht. Die Herstellung der elektronischen Bauelemente erfolgte mittels verschiedener Druckverfahren mit elektrisch leitfähigen und dielektrischen Materialien auf Polycarbonatfolien. Im Fokus standen zum einen kapazitiv auslesbare Speicherstrukturen und zum anderen Elektrolumineszenzleuchten. Nach dem Druck wurden die bedruckten Folien z. T. verformt und hinterspritzt. In der Arbeit wird auf die Auswirkungen der Verform- und Hinterspritzprozesse eingegangen. Schwerpunktmäßig wird die elektronische bzw. optische Funktionalität der Bauelemente, die Beeinflussung durch Klimaveränderungen und die Haftfestigkeit der Folien betrachtet. Im Ergebnis konnten erstmals die Realisierbarkeit hinterspritzter elektronischer Bauelemente nachgewiesen sowie verschiedene Einflussfaktoren auf deren Funktionalität identifiziert werden. / Based on the application of film insert molding for graphic purposes, the utilization of this process for the integration of electronic devices into plastic components was examined. The manufacturing of the electronic devices was realized by applying electrical conductive and dielectric inks on polycarbonate foil by various printing processes. Capacitive data storage patterns and electroluminescent lamps are the main applications. The production sequence included the printing process, forming of the foil where required and back injection molding. The impact of forming and film insert molding was investigated. The electronic and/or optical functionality of the devices, the influence of ambient conditions like temperature or humidity and the adhesion strength of the foils were in the focus of the evaluation. As a result, the feasibility of film insert molded electronic devices could be verified and various impact factors could be identified for the first time.
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