Don't stop believin'? Zur beunruhigend aktuellen These vom fortwährenden Nutzen des römischen Imperialismus

This article provides a critical discussion and refutation of the following study, which received some attention in the German media: "M. Obschonka et al.: Roma Eterna? Roman rule explains regional well-being divides in Germany, in: Current Research in Ecological and Social Psychology 8 (2025), https://doi.org/10.1016/j.cresp.2025.100214

Development and evaluation of an advanced wire-arc directed energy deposition process with integrated temperature control and in-situ heat treatment

The acceptance of Directed Energy Deposition with Arc (DED-Arc) in industrial applications is increasing due to ongoing research and development. A key challenge is maintaining temperature control, which affects process efficiency, sustainability, and the properties of the components. There is a need to actively modify the thermal conditions during the process to flexibly optimize the manufacturing quality and efficiency. This work aims to design and validate an advanced wire-based DED-Arc process with closed-loop temperature control and in-situ heat treatment for various applications. The existing DED-Arc system was enhanced by integrating cobot-guided in-situ cooling with nitrogen, water, and air, as well as an inductor for localized heat input. Different control configurations were applied to enable a fully automated temperature-controlled process. The findings show that the basic in-situ cooling concepts can reduce waiting times by up to 65%. Scaling and integrating these concepts into a control system enabled the production of components using ER100S-G without any cooling pauses, despite an interlayer temperature of ≤ 200 °C. Compared to the reference without thermal management, specific in-situ cooling increased the offset yield strength (Rp0.2) by over 100 MPa, while targeted heat input raised the plastic elongation at fracture to over 40%. It was also possible to precisely demonstrate heat treatment with significantly varying hardness profiles of up to 150 HV and corresponding microstructural and phase changes within a single component. Validation tests showed that temperature control can effectively optimize the DED-Arc process, emphasizing the need for further research on flexible, autonomous thermal management.Projekt DEALTechnische Universität Münche

Thermal behaviour of switchable liquid crystal glazing under real environmental conditions

Switchable liquid crystal glazing presents several advantages over conventional glass facades by seamlessly incorporating shading functions directly into the glass structure. This technology eliminates the need for mechanical components, enhancing reliability and reducing environmental impact. It also features rapid response times, within fractions of a second, and allows for variable shading levels, enabling precise adaptation to individual needs, thereby improving thermal and visual comfort. However, the design of these systems presents challenges, particularly with regard to the heating of the glass panes due to the absorption of solar radiation, especially when shading. Since the liquid crystals are embedded directly within the pane arrangement of the glazing unit, heat is transferred to the glass, causing uneven heat distribution, specifically in the clamped, shaded edge areas, which increases the risk of thermal stress fractures. Two types of glazing, double and triple, were installed and tested under real weather conditions in a facade test building to measure and assess the temperature behavior within the glass pane structure over a period of three years using various shading scenarios. The study revealed temperature extremes ranging from -9.9  ∘C to 79.9  ∘C for triple glazing units (TGU) and -7.3  ∘C to 77.2  ∘C for double glazing units (DGU). Critical temperature differences between center and edge areas reached up to 47.9  ∘C (TGU) and 46.5  ∘C (DGU), exceeding the 40  ∘C resistance limit specified for float glass in DIN EN 572-1. Multiple linear regression analysis demonstrated that 78.7 % of temperature variance could be explained by environmental variables, with direct solar radiation and outdoor temperature being the dominant influencing factors. Despite theoretical risks for thermal fracturing based on temperature difference thresholds, no structural damage was observed during the entire monitoring period, suggesting higher thermal resistance of the LC-cells than anticipated. The results provide valuable data for developing predictive temperature control models and optimizing the reliability and durability of switchable glazing systems under real-world conditions.Projekt DEA

Managing design variants in Formula Student race cars : a digital engineering approach across multiple teams

Increasing product complexity, shorter development cycles and cross-domain integration demands pose significant challenges for modern race car engineering teams. In Formula Student teams, heterogeneous toolchains, manual data exchange, late system integration, and high personnel turnover hinder efficient collaborative development and lead to repeated knowledge loss. This paper presents an integrated digital-engineering framework combining graph-based design languages (GBDL), model-to-text transformations, natural-language interactions via Large Language Models (LLMs), and Git-based version control to address these issues. By formalizing design knowledge and storing it in a centralized design graph, the framework ensures digital consistency of data and models, supports automated vehicle design variant generation, and enables seamless cross-domain integration. Through case studies of three Formula Student teams, the methodology demonstrates quantifiable reductions in design iteration time, enabling the evaluation of more than 10 4 suspension variants within days instead of a few dozen manually created variants, while reducing hands-on engineering effort from minutes per variant to a largely unattended optimization process. The results indicate that the approach not only enhances efficiency and collaboration but also preserves design knowledge for long-term knowledge management and reuse. Looking forward, this methodology provides a scalable route toward further engineering automation, systematic variant-driven development, and early-stage design optimization supported by design languages and integrated downstream toolchains.Ministry of Science, Research and Arts of the Federal State of Baden-Württember

Planning by experiment: the innovation potential of urban experimentation for planning practice

By examining how urban experimentation fosters innovation in urban planning practices, this research contributes to the growing field of ‘urban planning by experiment’. It focuses on Tactical Urbanism (TU) as a form of city street experiments and analyzes its capacity to drive long-term change in municipal planning. Situated at the interface of planning theory, public sector innovation theory, transition studies, and transformative and transdisciplinary sustainability research - with a focus on sustainable urban mobility - this research engages with recent planning debates related to urban sustainability transitions and the need for a reorientation of planning practices. While experimental practices are proliferating in cities around the world and are often celebrated by practitioners and scholars alike for their transformative potential, empirical evidence is scarce of how and under what conditions these interventions impact and innovate planning in the long run. This research addresses this gap in two ways: First, it develops a conceptual framework that defines innovation in planning as change across three dimensions: thinking, doing, and organizing. It also identifies the conditions influencing the likelihood that such changes in planning occur, and novel approaches and outcomes from experiments are institutionalized. Second, the framework is applied and refined through a longitudinal case study of TU experimentation in Barcelona from 2013 to 2023. Barcelona was chosen as a case study because it has been using TU for over ten years. This long period of experimentation offers a rare chance to study whether and how experimental practices and their innovations evolve, become adopted, and institutionalized as well as their impact on planning practices. Methodologically, the research employs a reconstructed longitudinal case study design with a mixed-methods approach including document analyses, field observations, and ten semi-structured interviews with planners, politicians, academics, and civil society representatives. The findings reveal that, although urban experimentation creates valuable opportunities to test new approaches and ideas, its transformative impact on planning practice seems limited and depends on various contextual factors, including institutional, political, and cultural influences. By integrating conceptual development with empirical research, this study strengthens the theoretical-conceptual foundation of scholarship on ‘urban planning by experiment‘ and provides important empirical insights into how urban experiments (can) promote innovation in urban planning and support urban sustainability transitions, particularly in the domain of urban mobility

Muskat-Leverett two‐phase flow in thin cylindric porous media : asymptotic approach

A reduced‐dimensional asymptotic modeling approach is presented for the analysis of two‐phase flow in a thin cylinder with an aperture of order O(ε), where ε is a small positive parameter. We consider a nonlinear Muskat-Leverett two‐phase flow model expressed in terms of a fractional flow formulation and Darcy's law, with saturation and reduced pressure as unknown. The given flow seeps through the lateral surface of the cylinder. This exchange process leads to a nonhomogeneous Neumann boundary condition with an intensity factor εα (α≥1) that controls mass transport. Furthermore, the absolute permeability tensor comprises the intensity coefficient εβ, β∈R, in the transverse direction. The asymptotic behavior of the solution is studied as ε→0, that is, when the thin cylinder shrinks into an interval. Two qualitatively distinct cases were discovered in the asymptotic behavior of the solution: α=1 and ββ-1 and α>1. In each of these cases, two‐term asymptotic approximations are constructed for both reduced pressure and saturation, accompanied by rigorous asymptotic estimates. These approximations were then used to derive approximations for the pressure and flow velocity of each phase. Two one‐dimensional models corresponding to the two‐phase Muskat-Leverett flow are derived, depending on the values of parameters α and β (each model is a nonlinear elliptic–parabolic system of two differential equations).Deutsche Forschungsgemeinschaf

Transformer based semantic segmentation in large-scale urban point clouds focusing on rare classes

Automated semantic interpretation of three-dimensional scenes has increasingly drawn attention in the fields of autonomous driving, building information modeling, and robotics, where reliable scene understanding plays a fundamental role in enabling intelligent perception and decision-making. Point clouds, obtained through laser scanning or stereo image matching technologies, have been widely acknowledged as the most reliable data source for representing spatial environments, owing to their ability to provide accurate and detailed 3D information. With the advances of lightweight laser scanning devices and flexible acquisition platforms, the availability of massive and high-resolution 3D point clouds has significantly increased. This unprecedented scale and richness of data, however, also poses a strong demand for effective methods that are capable of comprehensively interpreting large-scale and fine-grained point cloud scenes. In particular, the diversity of object categories, the imbalanced class distribution, and the intricate contextual relationships in large-scale urban areas bring great challenges to 3D semantic segmentation. This research aims to address these challenges by developing novel methods and techniques that specifically focus on the 3D semantic segmentation of rare classes in large-scale urban point clouds. Hereby, the work provides contributions on four major aspects: (i) the hierarchical attentional framework tailored for large-scale point cloud segmentation, (ii) the embedding method of local surface features for fine-grained segmentation, (iii) the contextual joint augmentation strategy to strengthen the representation of rare classes, and (iv) the target-aware learning designed to enhance the segmentation of rare classes. To achieve effective 3D semantic segmentation of urban scenes, we proposed a novel framework that integrates the attention mechanism focusing on crucial regions within large-scale point clouds. To further improve the perception of local geometric structures, the framework incorporates the embedding method of surface features into the segmentation pipeline, thereby facilitating the robust representation of fine-grained geometry inherent in complex environments. Addressing the issue of imbalanced class distribution, particularly concerning rare classes, we designed a contextguided data augmentation strategy that selectively augments underrepresented classes under the constraint of their semantic and spatial contextual relationships. Moreover, focusing on unique geometric cues that characterize rare objects, we further developed a target-aware network that adaptively modulates attention to rare categories, thereby maintaining its high sensitivity to these underrepresented classes. The proposed methods were evaluated through experiments on different large-scale benchmark datasets collected from multiple platforms, i.e., airborne, mobile and terrestrial platforms. In our submission to the official Hessigheim 3D benchmark ranking, our framework achieved a mean F1-score of 83.8% and an overall accuracy of 90.5%. In particular, the F1-scores of rare classes, namely vehicles and chimneys, significantly exceeded the average performance of other published methods, with improvements of 32.0% and 32.5%, respectively. Additionally, comprehensive experimental analyses on three other open benchmark datasets, including the Paris-Lille-3D dataset, the Semantic3D dataset and the WHU-Urban3D dataset, further demonstrate the robustness and effectiveness of our rare class segmentation methods

Reduced variability in threshold switches using heterostructures of SiOx and vertically aligned MoS2

Two‐dimensional (2D) materials and their heterostructures offer promising pathways for intercalated ion migration and regulated filament growth in resistive switching (RS) devices, enabled by their van der Waals (vdW) gaps. In vertically aligned 2D materials, this vdW gap‐mediated ion transport holds great potential for high‐density integration and reliable RS performance for memristor crossbar arrays. However, the fundamental switching mechanisms and their contributions to the RS remain inadequately understood. In this work, we investigate silver (Ag) filament‐based threshold switching (TS) in heterostructures comprising vertically aligned 2D molybdenum disulfide (VAMoS2) grown via sulfurization and silicon oxide (SiOx). Compared to SiOx‐only devices, the SiOx/VAMoS2 devices exhibit TS with higher on‐threshold and hold voltages, each approximately 0.4 V, faster switching times down to 356 ns under a 4 V pulse, and a lower cycle‐to‐cycle on‐current variability of 3.0%. A physics‐based, variability‐aware model reveals that confined Ag ion migration within the vdW gaps in VAMoS2 forms ultrathin seed filaments, which guide filament growth in the SiOx layer. These findings establish SiOx/VAMoS2 heterostructures as a promising concept for reliable TS in vertical device architectures for emerging memories and neuromorphic computing.European Union's Horizon Europe Research and Innovation ProgramDeutsche ForschungsgemeinschaftEmmy Noether ProgrammeGerman Federal Ministry of Research, Technology and Spac

Self-consistent transformation of first-, second-, and third-order potential gradients among Cartesian, cylindrical, and spherical coordinates

Knowing how to transform potential gradients between different coordinate systems is of fundamental importance in potential field theory. For first- and second-order gradients, such transformations are conventionally dealt with in terms of vector-matrix notation. However, matrix notation is not helpful for deriving the expressions for transformation of third-order potential gradients. In this contribution, we derive the general detailed expressions for transformation of first-, second-, and third-order potential gradients between two coordinate systems by using the direct expansion method. As examples of these general expressions, we derive detailed expressions for forward and inverse transformations of physical components of first-, second-, and third-order potential gradients among Cartesian, cylindrical, and spherical coordinates. Laplace’s equation has been applied for a first validation of partial expressions. However, to validate all newly derived expressions in a systematic way, we propose the closed-loop transformation cycle method that presents a full-fledged commutative diagram of forward and backward transformations among all three coordinate systems, i.e., potential gradients can become themselves after the closed round-trip transformation cycle among Cartesian, cylindrical, and spherical coordinates. Results reveal that this transformation cycle method confirms the correctness of all derived expressions. These general expressions for transformation of first-, second-, and third-order potential gradients can be applied under arbitrary two coordinate systems, and their detailed expressions can be systematically validated by the proposed transformation cycle method.Deutsche Forschungsgemeinschaf