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A target costing based approach for a regional line in Germany for Automated train preparation and operation
No full textThis presentation presents an approach for evaluating the cost-efficient implementation of new technology to increase efficiency through the automation of railway operations
Compact MEMS-based Fabry-Perot interferometers for space applications
No full textWe present the design and first test results for a compact point spectrometer for space applications. The instrument operates in the thermal infrared wavelength range between 7.5 and 10.5 μm and uses thermopile detectors as a sensing element. Spectra are generated in the time domain by employing an electrically tunable MEMS-based Fabry-Perot filter. The overall mass of the instrument including electronics is around 300 g and the miniaturized design is suitable for use on small platforms like CubeSats or (micro)landers. The spectral resolution achieved by the instrument is around 30, sufficient to identify the broad spectral features typically present in rock forming minerals
Integration eines wissensbasierten Kabinenentwurfs in den multidisziplinären Optimierungsprozess für den Gesamtflugzeugvorentwurf
No full textUm die steigende Nachfrage für eine nachhaltige und preiswerte Luftfahrt zu erfüllen, suchen Flugzeughersteller und Fluggesellschaften nach neuen effizienteren und individuell anpassbaren Flugzeugkonfigurationen. Im entscheidenden ersten Schritt des Flugzeugentwurfs, dem Gesamtflugzeugvorentwurf, werden aktuell Handbuchmethoden und Abschätzungen aus Erfahrungswerten verwendet. Die Expertise und spezialisierte Methoden vieler Fachdisziplinen kann in diesem frühen Entwurfsschritt aufgrund fehlender Daten häufig nicht berücksichtigt werden. Dies führt zu ineffizienten Lösungen und Integrationsproblemen und damit zu einem zeit- und kostenintensiven Entwurfsprozess. In dieser Arbeit wird ein digitaler Entwurfsprozess vorgestellt, der Flugzeugvorentwurfdaten mit detaillierten Informationen für disziplinäre Analysen im frühen Entwurfsprozess ergänzt, und so einen kollaborativen Flugzeugvorentwurf ermöglicht. Dies verbessert die Effizienz des entwickelten Flugzeugs und reduziert Entwicklungszeit und Kosten. Dazu werden neue wissensbasierte Methoden entwickelt, die automatisiert verschiedene Kabinen- und Strukturentwürfe basierend auf den Top-Level Aircraft Requirements, den Zulassungsrichtlinien für Passagierflugzeuge und der Außengeometrie aus dem Vorentwurf generiert. Anschließend werden die Methoden in einen digitalen multidisziplinären Entwurfsprozess integriert, um so die Volumina und Massenverteilung der Kabinenelemente in den Vorentwurf zurückzuführen. Die initial erstellte Struktur ermöglicht eine detaillierten Strukturauslegung und Crashanalyse des Gesamtflugzeugs. Eine Fallstudie mit einer aktuellen Forschungskonfiguration zeigt den Einfluss der zusätzlichen Informationen auf das Resultat und die Effizienz des Gesamtentwurfes
Realtime Limb Trajectory Optimization for Humanoid Running Through Centroidal Angular Momentum Dynamics
No full textOne of the essential aspects of humanoid robot running is determining the limb-swinging trajectories. During the flight phases, where the ground reaction forces are not available for regulation, the limb swinging trajectories are significant for the stability of the next stance phase. Due to the conservation of angular momentum, improper leg and arm swinging results in highly tilted and unsustainable body configurations at the next stance phase landing. In such cases, the robotic system fails to maintain locomotion independent of the stability of the center of mass trajectories. This problem is more apparent for fast and high flight time trajectories. This paper proposes a real-time nonlinear limb trajectory optimization problem for humanoid running. The optimization problem is tested on two different humanoid robot models, and the generated trajectories are verified using a running algorithm for both robots in a simulation environment
Angular Divergent Component of Motion: A Step Towards Planning Spatial DCM Objectives for Legged Robots
No full textIn this work, the Divergent Component of Motion (DCM) method is expanded to include angular coordinates for the first time. This work introduces the idea of spatial DCM, which adds an angular objective to the existing linear DCM theory. To incorporate the angular component into the framework, a discussion is provided on extending beyond the linear motion of the Linear Inverted Pendulum model (LIPM) towards the Single Rigid Body model (SRBM) for DCM. This work presents the angular DCM theory for a 1D rotation, simplifying the SRBM rotational dynamics to a flywheel to satisfy necessary linearity constraints. The 1D angular DCM is mathematically identical to the linear DCM and defined as an angle which is ahead of the current body rotation based on the angular velocity. This theory is combined into a 3D linear and 1D angular DCM framework, with discussion on the feasibility of simultaneously achieving both sets of objectives. A simulation in MATLAB and hardware results on the TORO humanoid are presented to validate the framework's performance
Endemic states of integro-differential equation-based disease models
No full textAs recently demonstrated by the SARS-CoV-2 pandemic, infectious diseases may have a huge impact on society. Mathematical models of infectious diseases allow to predict their behaviour. This process makes it easier to plan mitigation actions. Moreover, by studying the long-term behaviour of a model mathematically, one can see when disease dynamics start to stabilize around an equilibrium or under which circumstances the disease dies out.
Our contribution is the study of an IDE-based model with varying population size which does allow for endemic behaviour.
In order to derive an endemic model based on integro-differential equations, we will include the possibility of natural birth and death in a model similar to the one presented in Wendler et al. (2026). Compared to other IDE-based models, this model is rather complex, also allowing for disease death. The fact that we have a varying population size influenced by both the natural birth and death rate, as well as the disease-induced mortality, make the model analysis more involved. Moreover, the definition of equilibria is unclear when considering non-constant population size. In order to study the model behaviour independently of the population size, we will introduce a normalized version of our model. While this technique was already applied to ODE-based models, this seems to be a novel approach to IDE-based models. As a main result, we show the stability of the disease-free equilibrium whenever the reproduction number is smaller than one. Moreover, we derive conditions under which the disease-free equilibrium becomes unstable for a reproduction number larger than one
Degradation mechanisms of a proton exchange membrane water electrolyzer stack operating at high current densities
No full textOn the path to an emission free energy economy, proton exchange membrane water electrolysis (PEMWE) is a promising technology for a sustainable production of green hydrogen at high current densities and thus high production rates. Long lifetime, increasing the current density and the reduction of platinum group metal loadings are major challenges for a widespread implementation of PEMWE. In this context, this work investigates the aging of a PEMWE stack operating at 4 A cm-2, which is twice the nominal current density of commercial electrolyzers. Specifically, an 8-cells PEMWE stack using catalyst coated membranes (CCMs) with different platinum group metal (PGM) loading was operated for 2200 h. To understand degradation phenomena, physical
ex-situ analyses, such as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), were carried out. The same aging mechanism were observed in all cells, in dependent on their position in stack or the specific PGM loading of the membrane electrode assembly (CCM): (i) a decrease of ohmic resistance over time related to membrane thinning, (ii) a significant loss of ionomer at anodes, (iii) loss of noble metal from the electrodes leading to deposition of small Ir and Pt concentrations in the membrane, (iv) heterogeneous enrichment of Ti on the cathode side likely originating from the cathode-side of the Ti bipolar plates (BPPs). These results are in good agreement with the electrochemical performance loss. Thus, we were able to identify the degradation phenomena that dominate under high-current operation and their impact on performance
Dependencies of DNA damage response genes to different types and qualities of ionizing radiation
No full textBackground
Radiation quality influences DNA damage complexity and repair. Particle irradiation is used in clinical treatment for
its enhanced precision; particularly, high-LET ions such as carbon ions are postulated to overcome resistance by
inducing complex, non-repairable DNA damage. Differences in radiosensitivity linked to DNA repair gene loss have
recently gained interest One option to exploit such vulnerabilities is synthetic lethality. However, a
systematic approach for exploring synthetically lethal gene defects across distinct beam qualities is currently
missing. This study is the first to employ a CRISPR-Cas9 screen and analysis of DNA repair kinetics to systematically
investigate the interplay between radiation type, dose, and DNA repair processes, laying the foundation for
precision therapeutic interventions
DLR closes the loop in fiber-reinforced 3D printing with EmpowerAX, SchallFTP projects
No full textBuilding on its work in EmpowerAX, the DLR and partners now aim to create a standardized, certifiable value chain that turns fiber waste into consistently reinforced thermoplastic filaments for 3D printing