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Modulare thermische Modellierung und Unsicherheitsanalyse von Getriebemotor-Baukästen
No full textAntriebssysteme sind im Betrieb stark durch thermische Randbedingungen, insbesondere Temperaturgrenzwerte, eingeschränkt. In der Projektierung werden thermische Betrachtungen meist durch die separate Analyse einzelner Antriebskomponenten durchgeführt. Eine ganzheitliche thermische Modellierung des Gesamtsystems ermöglicht umfassendere und präzisere Aussagen über das Systemverhalten.
In dieser Arbeit wird ein Baukastensystem entwickelt, das den modularen Aufbau des Gesamtsystems aus einzelnen Komponenten ermöglicht. Es werden Modelle für die verschiedenen Antriebskomponenten erstellt und ein Algorithmus entwickelt, der diese Einzelkomponenten automatisiert zu einem Gesamtsystem zusammenführt. Der Fokus der Modellbildung liegt auf der präzisen Abbildung des makroskopischen Systemverhaltens, wobei Unsicherheiten durch Fertigungsschwankungen, Messfehler und physikalisch vereinfachte Modelle berücksichtigt werden.
Um die Verluste von Modellen in verschiedenen Betriebsbereichen genau zu bestimmen, wird eine automatisierte Methode zur Messung von Wirkungsgraden entwickelt. Diese Methode ermöglicht eine präzise Aufteilung in einzelne Verlustkomponenten und deren Unsicherheiten, indem die Temperaturen während des Messvorgangs in einem engen Temperaturband gehalten werden. Der entwickelte Messablauf gewährleistet eine stabile Temperatur, was zu genaueren und zuverlässigeren Ergebnissen führt.
Zur Validierung der Modelle werden Messungen unterschiedlicher Lastprofile für einen Solomotor und einen Getriebemotor durchgeführt. Ein Vergleich der Messergebnisse mit den Vorhersagen des thermischen Modells, einschließlich der berechneten Unsicherheiten im Temperaturverlauf, zeigt, dass die Messergebnisse innerhalb des berechneten Konfidenzintervalls liegen
Local structure and dynamics of a Zr-based bulk metallic glass during ex situ and in situ annealing
No full textAdvanced transmission electron microscopy (TEM) techniques are utilized to investigate the structural evolution and underlying mechanisms driving relaxation in metallic glasses. We quantify changes in medium-range order (MRO) using fluctuation electron microscopy (FEM), while electron correlation microscopy (ECM) combined with in situ heating allows us to directly probe local dynamics with unprecedented spatial resolution. FEM analysis provides a semi-quantitative estimate of the MRO volume fraction, based on either the peak height or the peak integral of the variance. This measure was found to increase in structurally relaxed samples compared to the as-cast condition, observed across both predefined annealed states and during in situ heating. Complementary in situ analyses uncover a temperature-dependent reduction in atomic mobility. This decrease in dynamics—which aligns with the phenomenon of irreversible structural relaxation, often termed ”aging”—is examined with high spatial resolution for the first time. The findings on structural modifications and local relaxation behavior during heating are discussed in detail and compared with results obtained via other characterization methods and across different material systems, providing a comprehensive understanding of relaxation processes in metallic glasses
Cross-Validation of Muon Content in Extensive Air Showers with Surface and Underground Detectors of AugerPrime
No full textDataset for the paper entitled "AIDA Arctic transport experiment part 1: simulation of northward transport and ageing effect on fundamental black carbon properties" by Zanatta et al. (2025)
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A Mg²⁺-Regulated Hydrated Vanadium Oxide Positive Electrode for Aqueous Mg-Ion Batteries
No full textAqueous Mg-ion batteries (AMIBs) have emerged as promising candidates for grid-level energy storage systems, thanks to their exceptional safety characteristics, cost-effectiveness, and abundant Mg resources. However, AMIBs confront great challenges, such as the shortage of high-performance electrodes and the sluggish Mg2+ diffusion in the electrodes. In this work, a Mg2+-regulated bilayered vanadium oxide (MgVOnH) positive electrode, holding a large interplanar spacing of ∼13.4 Å, was investigated in 0.8 m Mg(TFSI)2–85% poly(ethylene glycol) (PEG)–15% H2O and 0.8 m Mg(TFSI)2–65% PEG–20% dimethyl sulfoxide (DMSO)–15% H2O (20% DMSO-containing) electrolytes. MgVOnH delivers a first discharge capacity of 268 mAh g–1 at 50 mA g–1, obtaining 81% capacity retention after 100 cycles (against a second discharge capacity of 249 mAh g–1) in a DMSO-free electrolyte, whereas MgVOnH exhibits much better rate capability and high capacity at 500 and 1000 mA g–1 in the DMSO-containing electrolyte, respectively. Particularly, MgVOnH shows a first discharge capacity of 106 mAh g–1 at 1000 mA g–1, maintaining 80/65% of its capacity after 920/2000 cycles. Furthermore, the electrochemical reaction mechanism and reversibility of MgVOnH during Mg2+ (de)intercalation are systematically explored through ex situ techniques. This work helps us to understand the mechanisms, and this can guide us in achieving a better design for high-performance positive electrodes for AMIBs
Adhesion forces between AFM tips and TiO₂ nanoparticles to investigate the formation of natural coatings
No full textWhen nanoparticles enter aquatic environments, they acquire natural surface coatings (eco-coronas) that govern their fate, transport, and toxicity. This study employs atomic force microscopy (AFM) adhesion force mapping to characterize these coatings following in situ formation under natural conditions. Titanium dioxide nanoparticles (n-TiO) and flat single-crystal TiO substrates (absence of curvature and roughness effects) were exposed to three chemically distinct surface waters, revealing pronounced variability in adhesion force strength, range (min–max differences), and spatial patchiness, nanoscale heterogeneity metrics inaccessible to bulk techniques.
Moran’s I analysis of crystal-TiO confirmed positive spatial autocorrelation across samples, indicating patchy eco-coronas. Terrestrially dominated water (high DOC, humic-rich) produced the widest adhesion ranges, reflecting polydisperse humic adsorption. Microbial-enriched waters exhibited high adhesion forces comparable to terrestrial waters but lower variability ranges, while calcareous water (high Ca, ionic strength) yielded the lowest forces with less ordered spatial patterns. Moreover, sessile drop contact angle measurements on crystals further revealed macroscopic hydrophilicity changes.
In addition, complementary analyses of particle size, morphology, surface charge, and functional groups of the exposed nanoparticles to the surface waters provided multi-technique validation of surface modifications. These results establish AFM adhesion mapping as a powerful approach for resolving eco-corona heterogeneity under environmentally relevant conditions
An Automated Approach to Generating Card-Based Cryptographic Protocols
No full textCard-based cryptographic protocols provide a simple and illustrative way of performing multi-party computation without computers, but instead use just a set of playing cards. A lot of research has been done on finding minimal protocols, with respect to the number of cards or the number of protocol steps, for various functions. To automate the process of finding new card-based protocols, Koch, Schrempp, and Kirsten (2021) employed the technique of software bounded model checking for a symbolic program that implements the basic actions and states. The bounded model checker is then used to synthesize a secure protocol by automatically generating a bounded (symbolic) program run, or, if there exists no such run, prove impossibility within the given bounds.
In this thesis, we evaluate and extend the above technique for a generalization to more boolean functions, for an introduction of modularity so that (more) complex protocols can be found more efficiently, and finally for using bitwise datatype encodings so that finding protocols can be done more efficiently. From the increased efficiency and more universal applicability, we were able to extend the scope of the automated approach for generating card-based protocols to further impossibility proofs and various more protocols, for which some of them had already been found manually (but not formally verified) within literature
Amidinate, NHC, and Thioamide-based Ligands for the Construction of Luminescent Mono- and Heterobimetallic Transition Metal Complexes: Synthesis, Structure, Luminescence, and Catalytic Applications
No full textDie vorliegende Dissertation befasst sich mit der Synthese von Übergangsmetallkomplexen mit fortschrittlichen Ligandensystemen, insbesondere einem Phosphanacetylid-funktionalisierten Amidinatliganden, einem Cumarin-substituierten NHC-Liganden und einem t-Bu-substituierten Thioamidinatliganden. Die Metallionen mit den Elektronenkonfigurationen d8 und d10 wurden ausgewählt, da sie bekanntermaßen interessante optische und katalytische Eigenschaften aufweisen. Die synthetisierten Metallkomplexe wurden mit Hilfe von Standard-Analysemethoden charakterisiert und auf ihre photophysikalischen Eigenschaften hin untersucht
Leveraging Large Language Models for Intelligent Customer Service Channel Navigation
No full textCustomer-centric organizations offer multiple channels for customer service, allowing customers to reach out as needed. A common challenge, however, is that customers often default to the general support hotline, even when other channels may be more appropriate for their requests. The rise of Large Language Models (LLMs) presents an opportunity to enhance customer experience by leveraging their reasoning and decision-making capabilities for optimized channel selection. In this study, we explore the potential of LLMs to route customers to the most suitable service channel within a large European insurance company. Our approach involves collecting data on customer preferences for different channels across various scenarios, as well as their underlying reasoning. Through a series of experiments, we empirically assess the ability of LLMs to classify customer preferences and explain their reasoning. Our findings provide valuable insights into the feasibility of utilizing LLMs as decision-support tools for customer service channel routing