Eldorado - Repositorium der TU Dortmund

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Bei diesem Service handelt es sich um das Institutionelle Repositorium der Technischen Universität Dortmund. Hier werden Ressourcen aus und für Lehre, Studium und Forschung gespeichert, erschlossen und der Öffentlichkeit zugänglich gemacht.

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Aktuellste Veröffentlichungen

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    Molecular thermodynamics of complex coacervate systems. Part II: Measuring and modeling of the phase envelope using pePC-SAFT
    (Elsevier BV, 2024-12-05) Ascani, Moreno; Lipínski, Wojciech P.; Smokers, Iris B.A.; Neethirajah, Piramsuya; Vogel, Max; Spruijt, Evan; Sadowski, Gabriele; Held, Christoph
    Complex coacervation is an associative liquid-liquid phase separation (LLPS) observed in aqueous solutions of oppositely charged polyions. Coacervates are relevant systems in biology, chemistry, food and cosmetics industry, medicine as well as in engineering e.g. as extracting agents, for drug delivery or as gelling, foaming or stabilizing agents. Unfortunately, accurate experimental data on equilibrium compositions of complex coacervates are still scarce in the literature. Here, the LLPS of the coacervate-forming system water-Na₂NADH-protamine sulfate was measured at T = 298.15 K and p = 1.013 bar and at different polycation/polyanion ratios. Qualitative features of the experimental phase envelope are carefully discussed based on molecular interactions in this system. Compared to equilibrium data of the system water-Na₂NADH-poly-l-lysine HBr, the system water-Na₂NADH-protamine sulfate revealed a larger miscibility gap, suggesting a strong contribution of non-coulombic interactions to the phase behavior of this coacervate system. Experimental data were successfully modeled using the recently developed pePC-SAFT (Ascani et al., Part 1, Fluid Phase Equilibria, under review). The pePC-SAFT predicted phase envelope was in very good agreement with the measured experimental points. To the best of our knowledge, this is the first time that a physically sound model was used to model the phase envelope of a biologically relevant complex coacervate system.
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    Minimum degree conditions for containing an r-regular r-connected spanning subgraph
    (2024-02-26) Hahn-Klimroth, Max; Parczyk, Olaf; Person, Yury
    We study optimal minimum degree conditions when an n-vertex graph G contains an r-regular r-connected spanning subgraph. We prove for r fixed and n large the condition to be δ(G)≥(n+r−2)/2 when nr≡0 (mod 2). This answers a question of M. Kriesell.
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    Modeling and analysis of discrete particle detection in wide-field surface plasmon resonance microscopy
    (Elsevier BV, 2024-03-08) Al-Bataineh, Qais M.; Telfah, Ahmad D.; Tavares, Carlos J.; Hergenröder, Roland
    Wide-field surface plasmon resonance microscopy (WF-SPRM), based on Kretschmann’s configuration, is a powerful technique for detecting nano-objects in solution. In this study, key parameters for building a highly sensitive WF-SPRM are optimized, including laser wavelength, prism refractive index, numerical aperture of the objective, and gold layer thickness. A medium model describes the surface plasmon resonance (SPR) sensor principle, treating molecules bound on the sensor surface as an effective medium with an effective refractive index and thickness. On the other hand, the SPR discrete particle model is introduced to describe the detection principle for discrete particles. Theoretical, numerical, and experimental analyses are conducted, and the calculated intensity profiles of single and double nanoparticles from the discrete particle model describe the experimental profiles well. Furthermore, the influence of coating the gold layer with a dielectric layer on the SPR sensitivity is investigated for varying refractive indices.
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    Deformation-induced damage in finitely-strained metal sheets: Large-area damage quantification and mechanical property assessment
    (2026) Gerlach, Jan; Reclik, Tom; Wollenweber, Maximilian Aeneas; Gitschel, Robin; Hahn, Marlon; Al-Samman, Talal; Korte-Kerzel, Sandra; Kerzel, Ulrich; Korkolis, Yannis P.
    Reliable identification of damage-induced property changes in formed metal sheets remains challenging because plas-tic deformation alters the mechanical response through several coupled mechanisms. Moreover, pronounced ductile damage evolution occurs predominantly under inhomogeneous states of deformation, e.g., strain localization, which compromises the characterization of potential effects of damage on macroscopic mechanical properties, e.g., elastic stiffness. In this study, damage in dual-phase steel DP800 sheets is isolated from other concurrent mechanisms using a novel “sheet extrusion” process. The flat, finitely-strained sheets exhibit large regions with homogeneous properties, enabling subsequent characterization of damage-induced property changes. Damage in the form of microscopic voids is then characterized by large-area scanning electron microscopy (SEM) measurements, and damage-induced property changes are determined by subsequent characterization tests on specimens extracted from the extruded sheets. It is found that deformation-induced damage does not measurably affect the apparent elastic stiffness or the pre-necking tensile response. In contrast, differences in fracture-related performance quantities, i.e., the remaining ductility and the tensile impact energy, indicate that higher deformation-induced damage promotes earlier macroscopic failure by increasing the likelihood of local void coalescence during subsequent loading.
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    High Speed Forming 2025
    (2025-08) Korkolis, Yannis P.; Daehn, Glenn S.