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Sequential Chemo-Mechanical Phase-Field Modeling of Corrosion-Induced Cracking in Geothermal Pipes
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Hybrid DEM-VoF Multiphase Model for Microchannels of Electrochemical Devices
No full textIn proton exchange membrane (PEM) electrolyzers and in low-temperature PEM fuel cells, the reaction process leads to the formation of two-phase flow in microchannels. Therefore, the secondary phase needs to be removed effectively to ensure high performance and longevity of the device. A deeper understanding of this removal process is needed to optimize the cell design of electrochemical devices. Computational fluid dynamics (CFD) is widely used to investigate multiphase flow. Because different flow regimes ranging from disperse to continuous flow occur in the microchannels of such devices, the selected multiphase model needs to capture different length scales. The volume of fluid (VoF) method requires high mesh resolution to accurately capture the interface between the phases. Consequently, for disperse flow, this method incurs a high computational cost. In contrast, the Euler-Euler model might be computationally more efficient but is only applicable to the disperse phase, so it cannot capture the wide range of length scales present in the system. To bridge this scale gap efficiently, hybrid models have been developed that use different model equations depending on the local flow topology. In literature, the combination of the Euler-Euler model for the disperse phase with a VoF model for large interfaces is the most common. While effective for large-scale processes, these models neglect surface tension in the disperse phase, preventing accurate prediction of the detachment dynamics of droplets or bubbles in microchannels. In this contribution, we propose using a hybrid model that couples a discrete element method (DEM) for the disperse phase and its transition to large structures with a VoF method for large structures. The DEM is an extension of the Euler-Lagrange framework to finite-size particles. This DEM-VoF approach is intended to capture detachment dynamics accurately and, as a result, to enhance prediction of multiphase flow in microchannels. First, we develop the DEM component for modeling detachment dynamics and validate it by comparison to experimental data from literature. Next, we describe the coupling strategy between VoF and DEM and demonstrate the application of this methodology. With this approach, a more physical and efficient simulation for two-phase flow in microchannels of electrochemical devices is possible
A New Integrated Multi-Physics Simulation Tool for Gyrotron Cavity Performance Evaluation
No full textAdaptive Laboratory Evolution of Cupriavidus necator to Improve Energy Demand in Bioelectrochemical Cultivations
No full textThis study investigates adaptive laboratory evolution (ALE) to improve the tolerance of Cupriavidus necator H16 ΔPHB to high electrolyte concentrations, enabling more energy-efficient electroautotrophic cultivation. Over 3 months, strains were gradually adapted to up to 400 mM Na2SO4. Compared to the wild type, adapted strains exhibited higher growth under elevated salt conditions, maintaining viability at concentrations up to 300 mM. In bioelectrochemical systems, the addition of Na2SO4 significantly increased medium conductivity, reducing the cell voltage required under galvanostatic conditions. As a result, energy demand for cultivation decreased. Experiments demonstrated that the adapted strain grew comparably to the wild type under standard conditions but performed markedly better under high-salt conditions, shortening lag phases and reaching higher optical densities. Calculations revealed an energy saving of approximately 11% during 204 hr of cultivation when using the adapted variant in electrolyte-supplemented media. This work highlights the potential of combining biological robustness with optimized electrochemical conditions to reduce energy input in microbial electrosynthesis. Unlike purely technical optimizations, ALE provides a straightforward, natural, and transferable strategy to adapt production hosts to electrochemical process conditions. The findings demonstrate a practical route toward more sustainable bioelectrochemical processes by lowering energy consumption without compromising microbial performance
„Die Wertschöpfung sollte im Land bleiben“ – Forschende des KIT legen Ergebnisse eines Reallabors zum automatisierten ÖPNV vor - Campus-Report am 10.03.2026
No full textIn Beijing und Los Angeles gehören sie bereits zum alltäglichen Straßenbild. Fahrerlose Sammeltaxis und Shuttlebusse sind in China und den USA mit Millionen Fahrten unterwegs. In Europa dagegen gibt es bisher nur kleine Pilotflotten mit ein paar Dutzend Fahrzeugen auf ausgewählten Strecken. Mit den Fortschritten der Künstlichen Intelligenz kann sich das ändern. Die KI revolutioniert inzwischen auch das Konzept des Autonomen Fahrens hierzulande. Forschende des Karlsruher Instituts für Technologie haben die Ergebnisse eines so genannten Reallabors für den automatisierten Busbetrieb vorgelegt. Für das Forschungsprojekt RABus testeten 1400 ProbandInnen viereinhalb Jahre lang die Eignung speziell entwickelter, elektrisch betriebener selbstfahrender Kleinbusse für den Einsatz im Öffentlichen Personennahverkehr. In den Städten Friedrichshafen und Mannheim absolvierten sie mehrere hundert Fahrten. Fazit: die allgemeine Akzeptanz für Roboterbusse ist groß. Allerdings müssen die Rahmenbedingungen stimmen
Discovery of a Novel Coumarin/Thiazole Chalcone Hybrid as a Potent Dual Inhibitor of Tubulin and Carbonic Anhydrases IX & XII with Promising Anti-Proliferative Activity
No full textMultitarget-directed ligands offer a promising strategy for overcoming tumor complexity through simultaneous modulation of complementary oncogenic pathways. In this work, a novel (E)-6-(3-(4-methyl-2-thioxo-2,3-dihydrothiazol-5-yl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (compound 6) was synthesized and evaluated as a dual inhibitor of tubulin polymerization and tumor-associated carbonic anhydrases (CAs) IX and XII. Compound 6 displayed potent antiproliferative activity, particularly against MDA-MB-231 triple-negative breast cancer cells (IC = 0.37 µM), with excellent selectivity toward non-tumorigenic cells. Mechanistic studies demonstrated strong tubulin polymerization inhibition (IC = 3.40 ± 0.09 µM) and submicromolar inhibition of CA IX (IC = 0.102 ± 0.005 µM) and CA XII (IC = 0.213 ± 0.004 µM), accompanied by downregulation of CA-IX and CA-XII protein expression. Cellular investigations revealed pronounced G2/M phase arrest and apoptosis induction via mitochondrial signaling and caspase activation. Anti-angiogenic activity was supported by inhibition of endothelial migration and concentration-dependent suppression of VEGFR-2 (Tyr1175) phosphorylation in HUVEC cells. Human liver microsomal assays indicated measurable metabolic stability, while molecular docking and in silico ADMET predictions supported target engagement and drug-like properties. Collectively, these findings identify compound 6 as a promising multitarget anticancer lead integrating antimitotic, metabolic, and anti-angiogenic mechanisms
Interplay of Ionic and Electronic Properties of LPSCl with Its Micro- and Macrostructural Dynamics
No full textA systematic study is performed to correlate the electronic and ionic properties of Li6PS5Cl (LPSCl) with its mechanical properties and structural dynamics as a function of pressure and temperature. The crucial role of mechanical and structural dynamics, from the atomic to the macroscale, is investigated to optimize electrolyte properties and assembly. Ionic conduction dynamics are described via particle rearrangement, plastic deformation, contact formation, and activation volume with respect to structural dynamics during compression and decompression. The results demonstrate the potential for optimizing electrolyte performance through the interplay of opportune pelletizing and stacking pressures. High pelletizing pressures enhance ionic conductivity and electrical contact uniformity, whereas pressures below 80 MPa introduce interface contact instabilities. Additionally, it is shown that applying high pressure (above 10 GPa) results in irreversible structural modifications. At pelletizing pressures, ionic conductivity is dominated by grain boundaries; at stacking pressures, however, they contribute equally to the grain bulk. As a result of positive activation volume, ionic conductivity peaks at a stack pressure of 80 MPa, after pelletizing at a higher pressure. Defects can introduce donor levels into the energy gap of LPSCl, which can be adjusted to improve battery performance
Optimizing product yield and composition in chemical recycling of mixed plastics through temperature-staged pyrolysis
No full textChemical recycling of plastic waste via pyrolysis contributes to higher recycling rates in a circular economy. One
important prerequisite is the conformity of pyrolysis products with defined chemical feedstock specifications. In
the pyrolysis of mixed plastics, specification compliance is particularly hindered by the presence of aromatic
compounds and heteroatom-containing species (e.g., Cl, N, O) in the pyrolysis oils. Temperature-staged pyrolysis
facilitates oil decontamination, but scaling up this concept in pyrolysis processes poses challenges. Therefore,
investigations in thermogravimetry (TG) and a scalable stirred-tank reactor (STR) system are performed. Under
well-defined TG conditions, low temperature stages allow for dehalogenation and the selective decomposition of
non-polyolefinic polymers. Polyolefins decompose mainly in a separate stage at higher temperatures above
400 ◦C. Polymer interaction effects significantly influence the decomposition kinetics and depend strongly on the
polymer type in the mixture. The application in the STR system confirms technical feasibility, but also reveals
scale-up engineering challenges through heat and mass transfer limitations. The heat transfer limitations reduce
the polymer temperature during the two-staged STR process, requiring a higher first-stage set temperature than
in TG. Compared to isothermal pyrolysis at 500 ◦C, the total heteroatom content in the oil produced in the second
stage decreases. Toluene, benzoic acid, and ε-caprolactam content are reduced by a factor of 2–3 while aliphatic
compounds are enriched. Staging also facilitates the separation of heteroatom-containing gases from the
aliphatic-rich gas fraction. In contrast, elevating the first-stage pyrolysis temperature from 370 ◦C to 430 ◦C
reduces the target product yield from 56 wt.% to 23 wt.%. However, the temperature elevation also results in a
higher quality of the target product because of a reduced amount of incorporated non-aliphatic compounds.
These findings highlight the trade-off between maximizing the yield and enhancing the quality of the aliphaticrich
target product fraction