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Radiation effects in silicon photonic modulators of the COTTONTAIL chip
Get PDFWe report on results of irradiation experiments with ring modulators and Mach-Zehnder modulators of our current silicon photonic transmitter chip COTTONTAIL. Ex-situ experiments on ring modulators show a significant degradation from a total ionizing dose of more than 3 MGy and a difference in low and high frequency behavior. Forward bias annealing can mostly restore the pre-irradiation characteristics, but can leave a small penalty of up to 3 dB, even after extended annealing. In-situ experiments for continuous measurements while irradiating are currently prepared for ring modulators as well as for Mach-Zehnder modulators
Implementation and validation of the FaT laboratory for flow in rough fractures
Get PDFAccurate characterization of fracture hydraulics is crucial for optimizing subsurface systems, notably geothermal energy extraction where high flow rates are essential for efficient energy production. The precise transition from linear to nonlinear fracture hydraulics at already moderate flow rates is still undefined, due to the complexity of fracture roughness, where the influence of various roughness parameters and the comparability of individual rough fractures are still unclear. Here, we introduce the Forced Fluid Fracture Flow and Transport Laboratory (F4aT-Hydraulic Laboratory), a novel experimental laboratory designed to address this knowledge gap. It focuses on a comprehensive workflow encompassing high-resolution measurements of the rock surface roughness and the experimental investigation of fracture hydraulics at a large range of flow rates (0.05 < Re < 100). A unique feature of the F4aT-Hydraulic Laboratory is its ability to conduct systematic and stochastic investigations of roughness-hydraulic interactions through 3D printed fracture replicas with defined, statistically varied fracture roughness. In this study, we present the developed workflow in detail, provide benchmarking experiments against analytical solutions, and demonstrate the ability to measure roughness effects on the transition from linear to nonlinear hydraulic regimes at already moderate flow rates (Re ≈ 10)
Explaining Themselves and Making Friends: Towards Formalising the Sociability of Autonomous Agents
Get PDFWhile autonomous systems are integrated into more and more close-to-human application domains, we investigate sociability as a necessary extra-functional system property to ensure their integrability into diverse societies. To enable formalisation and formal validation of sociability of autonomous systems, we derive requirements for social rules from interdisciplinary sources. We further discuss explainability as a tool
for understanding social actions of autonomous systems
Demonstrating soft X-ray tomography in the lab for correlative cryogenic biological imaging using X-rays and light microscopy
Get PDFSoft X-ray tomography (SXT) enables native-contrast three-dimensional (3D) imaging of fully hydrated, cryogenically preserved biological samples, revealing ultrastructural details without the need for staining, embedding, or sectioning. Traditionally available only at synchrotron facilities, recent advances in laser-driven plasma sources have led to the development of compact soft X-ray microscopes. Achieving a resolution of 54 nm full-pitch and tomogram acquisition times of 30 min to two hours, we validate the system across a range of biologically relevant contexts, including protists, yeast, and mammalian cells containing polymeric and inorganic nanoparticles. These use cases establish the robustness of the laboratory based system for studying cell architecture, organelle interactions, and nanoparticle trafficking. By showing that a compact SXT system can achieve reliable high-resolution imaging across various cell types, this study highlights a major step toward making correlative cryogenic X-ray imaging broadly accessible in laboratory settings. Future developments will aim at enhanced throughput, deeper integration with correlative imaging modalities, and extension to more complex specimen types, including tissue
SSZ‐13 Zeolite with Isolated Co Sites as an Efficient and Durable Catalyst System for Non‐Oxidative Ethane Dehydrogenation
Get PDFNon-oxidative dehydrogenation of ethane (EDH) is an attractive method for on-purpose ethene production, but achieving high activity and, especially, durability with catalysts based on earth-abundant metals remains challenging. Herein, we introduce the Co/SSZ-13 system with exclusively divalent cobalt (Co) ions that meets the above requirements. The use of complementary characterization techniques enabled us to reveal two Cu species: Co─Z located in the six-membered-ring windows and [Co(OH)]─Z in the eight-membered-ring windows, with Z representing a charged zeolite framework site. A quantitative correlation between the rate of ethene formation and the site population establishes Co─Z as the active species. In situ X-ray absorption spectroscopy confirms their structural and electronic stability under high-temperature reaction conditions. The optimized 0.9Co/SSZ-13 (0.9Co) catalyst showed highly durable operation over 200 dehydrogenation/oxidative regeneration cycles at 600–650°C lasting for 150 h with industrially relevant productivity. In this regard, it outperforms almost all previously developed catalysts even those with platinum as an active component. The obtained results uncover the atomic-level origins of EDH activity/durability of the Co/SSZ-13 system and highlight the critical role of metal site location in designing highly active, selective, and durable catalysts for on-purpose ethene production
D4R: a new direct discrete dynamic data reconciliation method for the detection of cyber attacks
Get PDFA novel hybrid method of data reconciliation and gross error detection, applicable for systems with a mixture of dynamic and static system constraints, is developed for the detection of cyber attacks. The requirements for the new application of data reconciliation and similar methods in cybersecurity differ from the requirements for the established use of data reconciliation in automation and control engineering. For the detection of cyber attacks aiming at physical damage the main focus is on significant gross error detection while for classical applications a robust optimization and smoothing of measurement data is the main concern. Therefore the new hybrid method of direct discrete dynamic data reconciliation, as well as similar methods of data reconciliation and Kalman filters with their referring methods of gross error detection are evaluated regarding their aptitude for attack detection in cybersecurity. All considered methods are compared regarding properties resulting from the specific optimization procedure and the detection. The new direct discrete dynamic data reconciliation is indeed shown to outperform the other methods regarding the detection of cyber attacks
Photoluminescence characteristics and optical temperature sensing of orange-red emitting oxyapatite phosphor Ca₃La₇(SiO₄)₅(PO₄ )O₂ :Sm³⁺
Get PDFFrom Start to Finish - A Process of Using Simulation Software in Energy Research Projects
Get PDFSimulation software is crucial in energy research, serving as a key tool for analyzing complex systems and testing innovative solutions. Simulations are used in this context because real-world testing is typically expensive and time-consuming and may jeopardize the stability and safety of critical infrastructure systems. As part of NFDI4Energy, we are developing services to support researchers in effectively integrating simulation into their workflows.
To better understand the research community\u27s needs, we developed and analyzed multiple use cases that illustrate the diverse simulation-based processes in energy research. Based on these, we designed a structured process model that guides the use of simulation software, from planning and the initial setup over the execution to sharing results following the FAIR principles. Notably, the process also emphasizes the value of sharing simulation models and software, not just data, via dedicated software registries, thus enabling research data management.
Our goal within NFDI4Energy is to create new tools and services while integrating and connecting existing solutions through a shared service portfolio. This paper presents an overview of the identified requirements and the conceptual design of a Simulation-as-a-Service (SimaaS) approach tailored to the energy research domain, offering early insights into a potential future service landscape
Existence of traveling breather solutions to cubic nonlinear Maxwell equations in waveguide geometries
Get PDFWe consider the full set of Maxwell equations in a slab or cylindrical waveguide with a cubically nonlinear material law for the polarization of the electric field. The nonlinear polarization may be instantaneous or retarded, and we assume it to be confined inside the core of the waveguide. We prove existence of infinitely many spatially localized, real-valued and time-periodic solutions (breathers) propagating inside the waveguide by applying a variational minimization method to the resulting scalar quasilinear elliptic-hyperbolic equation for the profile of the breathers. The temporal period of the breathers has to be carefully chosen depending on the linear properties of the waveguide. As an example, our results apply if a two-layered linear axisymmetric waveguide is enhanced by a third core region with low refractive index where also the nonlinearity is located. In this case we can also connect our existence result with a bifurcation result. We illustrate our results with numerical simulations. Our solutions are polychromatic functions in general, but for some special models of retarded nonlinear material laws, also monochromatic solutions can exist. In this case the numerical simulations raise an interesting open question: are the breather solutions with minimal energy monochromatic or polychromatic