268 Works

Analog Hadronic Calorimeter for a Future Linear Collider

Amine Elkhalii

CMOS THz Camera Used as Compact Antenna Test Range

Robin Zatta, Vishal S. Jagtap, janusz grzyb & Ullrich Pfeiffer
In this paper, a silicon lens-integrated CMOS THz camera is employed as a compact antenna test range. The far-field radiation pattern of a 26-dBi 0.852-THz standard gain horn antenna radiation source is characterized. Both single-frame low-resolution and multi-frame super-resolution acquisition are performed. The latter is employed to measure a far-field radiation pattern with enhanced angular resolution. The directivity of the source is determined from both measured single-frame low-resolution and multi-frame super-resolution radiation patterns. The maximum...

CMOS Camera-Type THz Compact Antenna Test Range for Far-Field Radiation Pattern Analysis

Robin Zatta, Vishal S. Jagtap, janusz grzyb & Ullrich Pfeiffer
This paper presents a CMOS camera-type THz compact antenna test range (CATR) to facilitate a convenient means to measure far-field radiation patterns of transmitters (TXs). For concept validation, we measured the far-field radiation pattern of a 26-dBi 0.852-THz standard gain horn antenna-type TX with known far-field characteristics with the THz CATR. With the help of geometrical multi-frame super-resolution imaging, the directivity determination accuracy achieved at a peak signal-to-noise ratio (PSNR) of 34.8 dB is 0.2...

Performance Characterization Method of Broadband Terahertz Video Cameras

Vishal S. Jagtap, Robin Zatta, janusz grzyb & Ullrich Pfeiffer
Integrated THz systems comprising index matched optical media introduce discontinuities in the propagation path leading to an etaloning effect. The etaloning hinders the absolute accuracy of a measuring instrument thereby limiting its applicability. A methodology using computational notch filtering is implemented here to extract the true performance of a measuring instrument. Specifically, the responsivity and NEP of the portable room temperature 1k-pixel terahertz CMOS camera have been investigated using a continuously tunable broadband spectrally pure...

Performance Limits of THz Dispersive Spectroscopes Employing Super-Resolution Imaging

Robin Zatta & Ullrich Pfeiffer
The performance of terahertz (THz) dispersive spectroscopes is limited in spectral resolution and frequency accuracy due to a finite pixel count. This paper demonstrates that increasing the synthetic effective pixel count by exploiting super-resolution (SR) imaging results in improved performance. To this end, we investigated the performance of a CMOS camera-based THz dispersive spectroscope using SR imaging. From 0.75–0.9 THz, average spectral resolution improved from 76 GHz to 34.2 GHz (about a factor of two),...

Verbesserte Bedruckbarkeit von beschichteten Kartons mit wasserbasierten Inkjet-Tinten - Untersuchung zu Benetzung, Haftung und Wechselwirkung

Sandra Rosalen
Der zunehmende Einsatz des Inkjet-Druckverfahrens, vor allem im industriellen Bereich, ist unter anderem auf seine Modularität, seine Modifikationsmöglichkeiten für verschiedene Arten von Substraten und seine besondere Eignung für Kleinauflagen zurückzuführen. Der Druck von beschichteten Kartons erfolgt heute überwiegend mit UV-Tinten in Inkjet Drop-on-Demand-Drucksystemen oder mit kohlenstoffhaltigen, lösemittelbasierten Tinten in Continuous-Drucksystemen. Oberflächenmodifikationen von beschichteten Kartons werden, aufgrund des unterschiedlichen Verhaltens der Tinten, in der Regel für einen Typ von Tintenfarbmittel (Pigment oder Farbstoff) entwickelt. Wasserbasierte Inkjet-Tinten...

Application of Novel Analysis Workflows in an ATLAS Search for Supersymmetry

Martin Errenst
The size of the ATLAS collaboration results in a broad and diverse analysis software landscape. Previous and ongoing harmonization efforts aim to reduce the computational and storage footprint of analyses and provide common concepts to discuss and develop analysis software within the collaboration. In this dissertation, the recently introduced CP (Combined Performance) algorithms are studied in the context of an ongoing search for R-parity violating Supersymmetry in the final state of 1+ or 2 samesign...

Study of the Cosmic Ray Composition Sensitivity of AugerPrime - Probing the Prospects of the Upgrade to the Pierre Auger Observatory with a Deep Learning Approach

Sonja Mayotte
The composition of cosmic ray primaries at the highest energies is one of the biggest open questions in astroparticle physics, and is directly related to understanding the sources of ultra-high energy cosmic rays. At the Pierre Auger Observatory, cosmic rays are studied via the extensive air showers they produce in the Earth’s atmosphere. Improving the understanding of primary composition at the highest energies is the biggest motivation behind the upgrade of the Observatory, AugerPrime. The...

Xanthine-derived N-heterocyclic carbenes and their metal complexes

Moloud Mokfi
In the present study, a series of N-heterocyclic carbene (NHC) precursors derived from theophylline, theobromine, and caffeine have been synthesized. In this regard, ethyl p-toluenesulfonate (EtOTs) and diethyl sulfate (EtO)2SO2 were used as a new generation of alkylating agents to afford the ethylation of the NHC precursors at the N9 position. The structures of all products were evaluated and confirmed by NMR spectroscopy, high-resolution mass spectrometry (HRMS), and in some cases by elemental analysis (EA)....

Emergency Response Resilience to Floods Operationalised with Applied Geoinformatics

Katerina Tzavella
In cities, timely emergency response (ER) presupposes timely citywide accessibility enabled by the road transport system’s uninterrupted functioning. However, in this era of increasing frequency and intensity of extreme weather events and hydrometeorological hazards, delays or blockages challenge timely accessibility. Therefore, the thesis aims to contribute to saving lives by reducing losses in critical infrastructure (CI) functioning for adaptive emergency response (ER) provision towards the population’s and the emergency responders’ safety. For this purpose, the...

From Microscopic Models of Damage Accumulation to the Probability of Failure of Gas Turbines

Nadine Moch
Die Ausfallwahrscheinlichkeit spielt eine große Rolle bei der Entwicklung von Gasturbinenkomponenten, insbesondere in Bezug auf die Gewährleistung eines sicheren Betriebs. Die Komponenten unterliegen hohen mechanischen und thermischen Belastungen unter stark schwankenden zyklischen Bedingungen. In diesem Zusammenhang spielt das niederzyklische Ermüdungsverhalten (LCF) eine große Rolle. Das LCF Leben weist eine sehr große Streuung auf, was zu einem Versagen einer mechanischen Komponente vor Erreichen der deterministischen Lebensdauer führen kann. Es werden Sicherheitsfaktoren miteinbezogen, um Unsicherheiten, wie die...

Study on a miniaturized satellite payload for atmospheric temperature measurements

Jilin Liu
The atmospheric temperature reflects the thermal balance of the atmosphere and is a valuable indicator of climate change. It has been widely recognized that the atmospheric gravity wave activity has a profound effect on the large-scale circulation, thermal and constituent structures in the mesosphere and lower thermosphere (MLT). Temperature distribution in this region is an essential component to identify and quantify gravity waves. Observation from remote sensing instruments on satellite platforms is an effective way...

Solution Approaches for Multiobjective Convex Quadratic and Nonlinear Optimization Problems

Marco Milano
In this thesis three solution approaches for multiobjective nonlinear optimization problems are discussed. First, a class of multiobjective descent algorithms is introduced that can be understood as generalizations of descent algorithms known for the singleobjective case.
Several variants are investigated and compared with the weighted sum method. Furthermore, multiobjective convex quadratic optimization problems with linear constraints are discussed in the second part. Using the KKT conditions a parametric linear complementarity problem is derived which...

Scattering meson and baryon resonances in lattice QCD

Srijit Paul
We study meson and baryon resonances in QCD using lattice techniques. Specifically, we investigate the systems where two incoming stable hadrons strongly interact to form a resonance which then later decays to produce the same outgoing stable hadrons except for a difference in the phase. This phase shift encodes information about the resonance. On the lattice, the Lüscher formalism connects the infinite volume phase shift to finite volume spectra. In order to obtain the spectra...

Organic Sensitizers and Luminogens for Optoelectronic Devices

Şebnem Bayseç
Among the world of materials, organic semiconductors have attracted great attention due to their low cost, easy fabrication, and tunable properties. The development of high-performance organic materials over the past years have led to increase of their investigation and usage in optoelectronic field rapidly. So far, increasing the device efficiencies have been the main issue. From the chemist’s point of view, tailoring the properties of materials by facile synthetic modifications to enhance the efficiency of...

Rudolf Otto: ,Das Heilige. Über das Irrationale in der Idee des Göttlichen und sein Verhältnis zum Rationalen.' Kritische Edition mit einem Modell zur textgenetischen Variantenverzeichnung prosaischer Texte

Katharina Stäblein
Der Marburger systematische Theologe Rudolf Otto (1869–1937) hat sein Hauptwerk ,Das Heilige. Über das Irrationale in der Idee des Göttlichen und sein Verhältnis zum Rationalen’ (1917) in insgesamt 25 teils stark überarbeiteten zu Lebzeiten erschienen Auflagen hinterlassen. Der Forschung steht damit eine Vielzahl an Auflagen zur Verfügung, jedoch ermangelte es bisher einer kritisch gesicherten Textgrundlage. Die Verzeichnung dieses Textes stellt aus editionstheoretischer Sicht eine Herausforderung dar – besonders ob der Fülle der zu verzeichnenden Prosavarianten....

The Discursive Legitimation of New Ideas. Emergence and Diffusion of the Industrial Research Laboratory in the United States, 1870-1930.

David M. Pithan
Zu Beginn des 20. Jahrhunderts begannen amerikanische Firmen in der Chemie- und Elektroindustrie Forschungslabore zu etablieren, die später weltberühmt wurden. Während historische Studien typischerweise einzelne Industrielabore untersucht haben, beleuchtet der Vortrag das gesamte Organisationsfeld der amerikanischen Industrieforschung im Zeitraum 1870-1930. Es wird gezeigt, wie Forschung in Industrieunternehmen durch gesellschaftlich geteilte Vorstellungen von Wissenschaft legitimiert werden musste. Hierzu wird mithilfe einer umfassenden Diskursanalyse der kulturelle Kontext analysiert, in dem Industrielabore entstehen und sich verbreiten konnten.

Multigrid smoothers for saddle point systems

Lisa Claus

Donor-Akzeptor-Copolymere und Leiterpolymere aus oligocyclischen Strukturbausteinen

Florian Alexander Trilling
Im ersten Teil dieser Arbeit wird die Überführung Thiophen- bzw. Fluoren-basierter Diketopyrrolopyrrol (DPP)-Derivate, eine der gegenwärtig intensivst genutzten Gruppen von Akzeptor-Bausteinen, in oligocyclische Monomere, sog. ausgedehnter DPP (EDPP)-Derivate und deren Einbettung in Donor-Akzeptor (DA)-Copolymere sowie Leiterpolymere beschrieben. Während die Polykondensation der Thiophen-basierten EDPP-Derivate mit einer Vielzahl unterschiedlicher Donor-Bausteine zur Ausbildung von DA-Copolymeren mit breiten Absorptionsbanden bis in den Nah-Infrarotbereich und kleinen optischen Bandlücken von bis zu 1,6 eV führte, divergierten die Eigenschaften der Fluoren-EDPP-basierten DA-Copolymere...

Silicon-based Systems for Microscopic and Volumetric Terahertz Imaging

Philipp Hillger
Owing to the unique characteristics of terahertz (THz) waves and their interaction with matter, THz imaging has significant potential in diverse fields, including life sciences, non-destructive quality control, and security. However, today’s THz technology faces major obstacles in providing the cost, compactness, and functional scope that is required to facilitate a wide-reaching use outside the laboratory. Therefore, the general aim of this thesis is to increase the societal impact of THz technology by exploring novel...

Explorative Studie zur curricularen Einbindung photochemischer Inhalte in den Chemieunterricht

Yasemin Yurdanur

Voruntersuchungen für eine mechatronische Produktentwicklung von elektronischen Gas-Luft-Verbünden

Sabrina Resch
Die Entwicklung des europäischen Erdgasnetzes in den letzten Jahrzehnten hat dazu geführt, dass Unternehmen wie die Firma Vaillant GmbH vor immer größeren Herausforderungen gestellt werden, um eine stets sichere und effiziente Verbrennung gewährleisten zu können. Die Diversität in der Gasqualität fordert voll-gasadaptive Verbrennungsregelungssysteme in Gas-Heizgeräten. Ziel dieser Arbeit ist es, das bestehende Verbrennungsregelungssystem basierend auf der Messung eines Ionisationsstromes hinsichtlich einer Vergrößerung der Modulationsbandbreite zu optimieren. Dazu wurde das gesamte mechatronische System bestehend aus Brenner,...

Jordan Decomposition for the Alperin{McKay Conjecture

Lucas Ruhstorfer

Silicon Integrated Radio Front-End Design for 100 Gbit/s and Beyond

Stefan Malz
Wireless communication is one of the fastest growing fields of technology, which constantly enables new innovations in all sectors of industrial, scientific, and consumer applications. To meet the ever-increasing demand for higher data-rates, parts of the electromagnetic spectrum that were previously unexploited are being acquired for wireless communication. Particularly large bandwidth for high-speed communication is available in the high millimeter-wave frequency range above 200 GHz. Due to the recent technological progress, these bands have become...

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  • University of Wuppertal
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  • TH Köln – University of Applied Sciences
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  • Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute
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  • Nanchang University
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