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Naturkundliche Beobachtungen in Munchhausen (Frankreich) - Sauerdelta und Laurophyllisation in Munchhausen
No full textDas Delta de la Sauer bei Munchhausen ist ein einzigartiges Weichholzauen-Gebiet am Oberrhein, das durch die Rheinkorrektur entstand und noch heute 4–6 Monate jährlich überflutet wird. Hier dominieren urwaldähnliche Silberweidenbestände (Salix alba), während sich auf Kiesbänken Hartholzauen mit Eichen und Pappeln ausbilden. Besonders auffällig ist die Laurophyllisation – die Ausbreitung immergrüner, gebietsfremder Arten wie Prunus laurocerasus oder Arum italicum aus Gärten in die Natur, die nicht nur auf Klimawandel, sondern auch auf Landnutzungswandel zurückzuführen ist.
Kulturell war Munchhausen einst geprägt von Rheinfischerei, Korbflechterei („Vannerie“) und Obstanbau, heute dominieren Tourismus (Pamina-Radweg) und extensive Beweidung auf dem Grosswoerth, einer ehemaligen Rheinkiesbank. Das Naturschutzgebiet Réserve naturelle du delta de la Sauer beherbergt eine reiche Biodiversität: Über 50 Pflanzenarten (inkl. Neophyten wie Fallopia japonica), seltene Vögel (Weißstorch, Singschwan) und sogar Biber. Durch Mahd und Beweidung bleibt die offene Landschaft erhalten – ein lebendiges Beispiel für den Wandel von Kultur und Natur
Solar Flow Synthesis of Polymer Nanoparticles: Scaling Local Experiments to Global Potential
No full textWe present the scalable, additive-free synthesis of polymer nanoparticles in continuous flow, using solely solar radiation. Using a custom-made flow reactor, the UV radiation from the sun induces a Diels–Alder step-growth polymerization between a bismaleimide and a difunctional o-methylbenzaldehyde. The resulting photopolymer subsequently precipitates as nanoparticles without the need for any additional additives, stimuli or processing steps. The solar flow reactor was designed by first carefully assessing the underpinning photochemistry of the photo-induced Diels–Alder reaction using photochemical action plots and then performing a kinetic investigation of the particle formation under solar irradiation. The determined kinetics allow us to extrapolate our experimental results to a worldwide particle yield by using global UV index data, validated by two highly different geographical locations, Australia and Germany. Our results clearly demonstrate the applicability of our system for the scalable, sustainable, solar-powered production of polymeric nanoparticles in regions of high levels of solar radiation. Furthermore, our calculations function as a blueprint for how local experimental data can be extrapolated to assess the global solar photochemical potential of photochemical systems, thus making their performance comparable
Temperature-Annealed Boltzmann Generators
No full textEfficient sampling of unnormalized probability densities such as the Boltzmann distribution of molecular systems is a longstanding challenge. Next to conventional approaches like molecular dynamics or Markov chain Monte Carlo, variational approaches, such as training normalizing flows with the reverse Kullback-Leibler divergence, have been introduced. However, such methods are prone to mode collapse and often do not learn to sample the full configurational space. Here, we present temperature-annealed Boltzmann generators (TA-BG) to address this challenge. First, we demonstrate that training a normalizing flow with the reverse Kullback-Leibler divergence at high temperatures is possible without mode collapse. Furthermore, we introduce a reweighting-based training objective to anneal the distribution to lower target temperatures. We apply this methodology to three molecular systems of increasing complexity and, compared to the baseline, achieve better results in almost all metrics while requiring up to three times fewer target energy evaluations. For the largest system, our approach is the only method that accurately resolves the metastable states of the system
Modularized Platform for an Embedded Systems Case Study: Concept and Design
No full textProject-based learning is essential in bridging the gap between theoretical knowledge and practical application for electrical engineering students. To address this need, the Faculty of Electrical Engineering and Information Technologies (ETIT) at the Karlsruhe Institute of Technology (KIT) has developed a continuous mandatory workshop spanning the first four semesters. This workshop, executed alongside lectures and theoretical exercises, aims to provide students with a practical introduction to hardware-oriented programming and project management. In this context, the paper presents a newly-designed hardware platform for one part of the workshop, centered around a Tiva LaunchPad embedded on the control PCB of a modular remotecontrolled vehicle. The platform leverages various capabilities of the Tiva Launchpad, enabling students to gain experience using GPIO, ADC, PWM, and UART peripherals. Working in groups of three, students develop individual hardware-related classes that contribute to group tasks, ensuring collaborative learning and project management experience. The hardware platform adopts a modular structure, effectively separating main functions and power levels through three printed circuit boards (PCBs): the control PCB, battery management PCB, and power management PCB. Additionally, a remote-control interface facilitates human-machine interaction. The software architecture follows a modular approach, employing object-oriented programming principles. Overall, the hardware platform provides first-year electrical engineering students with a practical and comprehensive introduction to hardware-oriented programming and project management. By integrating software and hardware components, the platform
promotes a holistic understanding of systems engineering principles
When Rain Meets Surge: Assessing Future Typhoon‐Driven Compound Flood Hazard Profiles in a Rapidly Urbanizing Delta
No full textTyphoon-induced Compound Flood (TCF), driven by the combined impact of extreme rainfall and increasing coastal water level (CWL), poses a substantial threat to urban safety. This study presents a framework for assessing the future compound flood hazard profiles in a coastal megacity in the Delta region of southern China. A coupled hydrology-hydrodynamic model is applied to simulate the flooding processes of 7 typhoon events. Scenarios are constructed using all possible pairwise combinations of three rainfall and three CWL conditions. These inputs are derived from statistical and dynamical downscaling of climate projections from the Coupled Model Intercomparison Project (CMIP6) ensemble under the SSP5-8.5 pathway. The results show that future CWL rise contributes more to future inundation than increasing rainfall, whereas rainfall contributions exhibit considerable uncertainties due to regional rainfall downscaling. Under extreme warming scenarios, future typhoons may produce increases of up to 230 mm in total rainfall and 28 mm per hour in rainfall intensity, which in turn increase the average urban inundation depth and area by 1.2 cm and 24.7 km, respectively. Given an average CWL of 170 cm and a maximum CWL of 440 cm in the future, the inundation depth and area could increase by up to 8.4 cm and 29 km, respectively. Within the 7 typhoons in this study, Hagupit (2014) exhibits the most notable compound effect, potentially expanding the medium-to-high risk area (inundation depth above 27 cm) by over 5%. This study demonstrates that climate change may intensify TCF, requiring flood-mitigating measures to consider rainfall-CWL interactions
Extraction of band gap energies and composition of mixed-phase polycrystalline semiconductors; a possible alternative method
No full textThe optical band gap energy, Eg, of semiconductors is routinely determined using UV–Vis absorption measurements followed by Tauc‐plot analysis. This method requires knowledge of the Tauc exponent n, which corresponds to the nature of the electronic transition. While Tauc analysis is effective for single-phase semiconductors, it may not be applicable to mixed-phase materials that exhibit two different types of transitions. In this work, the absorbance of mixed-phase TiO (anatase and rutile) with varying compositions is examined. Anatase has an indirect band gap (n= 2), whereas rutile has a direct band gap (n = ½). It is shown that the first derivative of the absorbance with respect to the wavelength, dA/dλ, yields phase-composition information largely similar to that obtained from XRD analysis. Furthermore, the positive peak of the second derivative, dA/dλ, provides a band-gap value that does not shift (within <0.05 eV) with changes in TiO phase composition. The method was also tested on two additional semiconductors (ZnO and g-CN), yielding band-gap energies comparable to those obtained using established techniques. These results demonstrate that the band gap energy can be determined without prior knowledge of the transition type by using the second derivative of the absorbance
Which Reaction Conditions Work on Drug-Like Molecules? Lessons from 66,000 High-Throughput Experiments
No full textHigh-throughput experimentation (HTE) accelerates chemical discovery by shortening the lead times for molecule synthesis. The choice of initial reaction conditions directly influences the outcome and length of any reaction optimization. But human involvement in plate design and data analysis remains a significant cost factor and is accompanied by biases. Therefore, making the most out of past reaction outcomes is crucial. While advances in machine learning allow us to generate promising reaction conditions, this approach is often not suitable because not enough relevant reaction data are available or it is of insufficient quality. Herein we introduce a robust statistical method using z-scores to analyze 66,000 internal HTE reactions on complex molecules. Additionally, we publish the underlying data as well as a tool to analyze and draw actionable conclusions from this data set. We exemplify the power of this method for the widely employed Buchwald–Hartwig and Suzuki–Miyaura cross-coupling reactions. The results reveal optimal conditions that differ significantly from literature-based guidelines. These data-driven insights provide high-quality starting points for optimization campaigns, improving their overall efficiency
Quantitative Modeling of Thermo-Hydraulic Transport in Geothermal Fractures: A Diffuse Interface Perspective
No full textGeothermal energy systems are gaining importance as stable, CO-neutral energy sources supporting both climate goals and energy security. Accurate simulation of coupled heat and fluid flow in fractured media is critical for optimizing their efficiency. Diffuse interface models, grounded in phase-field theory, offer a promising alternative to classical sharp interface formulations. By avoiding explicit interface tracking, they naturally accommodate topological changes and enable efficient coupling between physical fields, which is particularly advantageous for geothermal systems.
In this study, we model fluid flow and heat transfer using the incompressible Navier–Stokes equations for a Newtonian fluid, with temperature treated as a passive scalar to allow one-way coupling from fluid flow to heat transport. Within the diffuse interface framework, various approximations exist to enforce no-slip boundary conditions at the fluid–solid interface in a diffuse manner, e.g., by introducing a dissipative term in the momentum equations. Since the specific choice of approximation significantly influences the accuracy of the diffuse model, we additionally employ an interface-orientation-dependent formulation of the heat flux to improve the thermal solution.
These improvements are implemented in the finite-difference in-house solver Pace3D and validated against analytical benchmarks, yielding errors typically below 1 % for the velocity and the temperature field. Furthermore, realistic fracture geometries are synthetically generated via spectral synthesis method[6] and assembled into flow channels. For these complicated geometries, we assess the convergence behavior of the phase-field model and compare it to a voxel-based sharp interface representation, demonstrating that phase-field models maintain acceptable accuracy even at low resolution. Finally, we investigate the influence of fracture geometry on heat transfer efficiency under varying thermal and flow conditions. The results highlight the sensitivity of convective transport to fracture morphology and boundary conditions, and lay the foundation for advanced phase-field models incorporating crystallization and dissolution processes in fractured geothermal systems
Erweiterung der DASt‐Richtlinie 026 um höchstfeste Baustähle und Berücksichtigung geometrischer Fertigungsimperfektionen
No full textDer Einsatz höchstfester Stähle bringt bei hoch beanspruchten Stahlkonstruktionen zahlreiche Vorteile mit sich. Bei ermüdungsbeanspruchten Konstruktionen führt die derzeitige Ausgestaltung der Ermüdungsnachweise in den einschlägigen Regelwerken, die die Kerbfalleinordnung unabhängig von der Werkstofffestigkeit vornehmen, jedoch zu einer limitierten Nutzbarkeit dieser Werkstoffe unter ermüdungsrelevanten Beanspruchungen. Durch den Einsatz höherfrequenter Hämmerverfahren (HFH) zur Schweißnahtnachbehandlung lässt sich die Ermüdungsfestigkeit geschweißter Verbindungen signifikant erhöhen, wohingegen dieser Effekt mit steigender Festigkeit des Grundwerkstoffs weiter zunimmt. Im Rahmen des Forschungsprojekts P 1505 wurde der Einfluss der HFH-Nachbehandlung auf die Ermüdungsfestigkeit höchstfester Baustähle bis S960 untersucht. Besonderes Augenmerk galt dabei auch geometrischen Fertigungsimperfektionen außerhalb der zulässigen Grenzen gemäß Bewertungsgruppe B der DIN EN ISO 5817. Ziel der Untersuchungen ist die wissenschaftlich fundierte Erweiterung der im Jahr 2019 veröffentlichten DASt-Richtlinie 026 sowie des neuen Anhangs F in FprEN 1993-1-9, um eine wirtschaftliche Ermüdungsbemessung von HFH-behandelten Schweißverbindungen aus höchstfesten Stählen zu ermöglichen
Comparative analysis of locomotory organs and tracheal system in Halarachne halichoeri: implications for marine parasite habits
No full textThe nasal mite Halarachne halichoeri thrives in a unique niche: the respiratory tracts of deep-diving seals, where it faces high hydrostatic pressures, hypoxia, and osmotic stress. Using synchrotron X-ray microtomography, 3D reconstruction, scanning electron microscopy, and confocal laser scanning microscopy, we reveal the mite’s adaptations to these extreme conditions. Its specialized attachment system, comprising two claws and a dynamic pad (arolium), enables secure anchorage to the soft mucosal surfaces. When anchoring to rough surfaces, the arolium actively folds inward with the help of a sclerite-tendon mechanism, allowing the claws to firmly embed into and interlock with the substrate. In contrast, on smooth surfaces, leg and claw angles are actively adjusted by tendons to retract the claws proximally, enabling the unfolded and extended arolium to contact and adhere to the substrate. The mite’s leg musculature is strongly developed, with powerful flexors and depressors ensuring stable attachment, while protractors and levators facilitate movement. The respiratory system features a highly reduced tracheal volume (only 0.04% of body volume) suggesting a predominant reliance on cuticular respiration. Thickened, taenidia-reinforced tracheae provide mechanical stability against collapse during the intense pressure changes encountered during host dives. These findings highlight the exceptional morphological and physiological strategies enabling H. halichoeri to survive in extreme environments