TY - CHAP A1 - Stocker, Philipp A1 - Lehrer, Tobias A1 - Duddeck, Fabian A1 - Wagner, Marcus T1 - Face-wise prediction of sheet-metal drawability using graph neural networks T2 - Journal of Physics: Conference Series N2 - The early design phase of deep-drawn structural components involves time-consuming iterative development. Traditional drawability assessments rely on finite element simulations, which are computationally expensive and slow the design process. Alternative machine learning (ML) approaches show promise in accelerating this process but face challenges with existing methods. Existing low-dimensional ML models only provide global predictions without identifying specific geometric regions prone to failure. High-dimensional models provide local predictions but require significant amounts of training data. We propose a data-driven approach leveraging graph neural networks (GNNs) for face-wise drawability prediction of sheet metal components in their computer-aided design (CAD) representation. Our method aims to bridge the gap between the computational efficiency of ML and the spatial resolution of simulation by providing face-wise insight into potential failure regions. This study utilises a dataset of parametric U-channel geometries with variability in both geometry and topology. Ground-truth labels are generated using inverse analysis simulations. Geometric entities are represented through the use of UV parameterisations, whereby 3D surfaces are mapped into 2D space to facilitate geometric encoding. Concurrently, the topological relationships are captured using a face adjacency graph. To address data scarcity, we evaluate how different amounts of training data affect model performance and perform ablation studies to analyse the impact of different CAD representation features. Our results show that the proposed approach achieves high accuracy even with limited training data. In addition, the ablation studies provide insights into the most critical CAD features, guiding future research. These results highlight the potential of our GNN to predict face-wise drawability in the early design phase. Y1 - 2025 U6 - https://doi.org/10.1088/1742-6596/3104/1/012053 SN - 1742-6588 N1 - Corresponding author der OTH Regensburg: Philipp Stocker VL - 3104 IS - 1 PB - IOP Publishing ER - TY - JOUR A1 - Hantsch, Carolin A1 - Westner, Markus A1 - Matschi, Markus T1 - IT/OT-Konvergenz: Status-Quo und Umsetzungsempfehlungen JF - HMD Praxis der Wirtschaftsinformatik N2 - Organisationen machen große Anstrengungen zur Verbesserung ihrer Ambidextrie, d. h. ihrer Fähigkeit sowohl Exploitationsziele (z. B. Effizienz, Vorhersagbarkeit) als auch Explorationsziele (z. B. Anpassbarkeit, Innovation) zu erreichen. Obwohl gemäß der Praxisliteratur Technologie in Software-Projekten dabei eine zentrale Rolle spielen kann, gibt es kaum Forschung dazu, wie technologische Faktoren Ambidexterie in Software-Projekten beeinflussen. In dieser Studie untersuchen wir die Rolle dreier technologischer Faktoren: kontinuierliche Integration, Standardisierung und Microservice-Architektur. Die Ergebnisse einer Mehrinformanten-Umfrage in 95 Projekten in der Schweiz und Dänemark zeigen, dass kontinuierliche Integration und Standardisierung mit höherer Ambidexterie einhergehen, während der Zusammenhang zwischen Microservice-Architektur und Ambidextrie nicht signifikant ist. Unser Artikel geht über die existierende Forschung hinaus, indem er zeigt, dass kontinuierliche Integration und Standardisierung nicht nur Exploitation, sondern auch Exploration fördern können. Wir diskutieren auch Gründe für den insignifikanten Zusammenhang zwischen Microservice-Architektur und Ambidextrie. N2 - This study examines IT/OT Convergence in 31 predominantly large German companies. It presents an “IT/OT Governance Framework” as a specific model for successful convergence implementation. The analysis reveals a heterogeneous level of convergence maturity across the examined companies, the majority of which are at the beginning or in the implementation phase. Close cooperation between IT and OT is favored, but without IT completely taking over OT. An IT/OT tandem consisting of a CIO and a central OT responsible person is seen as the ideal way to take responsibility. Six specific recommendations were derived from the interviews and included in the IT/OT Governance Framework developed. These include ensuring top management support, using security as a driver, introducing a central OT responsible person, bringing IT and OT teams physically closer together, continuously demonstrating the added value of convergence, and taking a step-by-step approach to implementation. KW - IT/OT Convergence KW - Operational Technology KW - OT KW - Governance Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-77937 N1 - Corresponding author der OTH Regensburg: Markus Westner PB - Springer Nature ER - TY - JOUR A1 - Schmid, Michael T. A1 - Thiel, Charlotte T1 - Is it worth it? Potential for reducing the environmental impact of bitumen roofing membrane production JF - Recycling N2 - Between 51% and 72% of a bituminous roofing membrane used for structural water-proofing consists of organic material, predominantly bitumen - a derivative of crude oil refining - highlighting the strong dependence of this product on fossil resources. Considering that several tonnes of these membranes must be replaced every 30 to 50 years, substantial potential exists for emission reduction through the establishment of circular material systems. This study investigates this potential by analysing 26 Environmental Product Declarations (EPDs) and life cycle datasets from across Europe covering the period from 2007 to 2023. To ensure comparability, all data were normalised to a declared unit of 1 kg of roofing membrane. The reinforcement layers were categorised into glass and polyester & glass composites, and their differences were examined using Welch’s t-tests. Correlative analyses and linear as well as multiple regression models were then applied to explore relationships between environmental indicators and the shares of organic and mineral mass fractions. The findings reveal that renewable energy sources, although currently representing only a small share of total production energy, provide a major lever for reducing nearly all environmental impact categories. The type of reinforcement layer was also found to influence the demand for fossil resources, both materially and energetically. For most environmental indicators, only multiple regression models can explain at least 30% of the variance based on the proportions of organic and mineral inputs. Overall, the study underscores the crucial importance of high-quality, transparently documented product data for accurately assessing the sustainability of building products. It further demonstrates that substituting fossil energy carriers with renewable sources and optimising material efficiency can substantially reduce environmental burdens, provided that methodological consistency and clarity of indicator definitions are maintained. KW - bitumen sealing KW - bitumen recycling KW - circular construction KW - correlation analysis KW - LCA Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86873 N1 - Corresponding author der OTH Regensburg: Michael Schmid VL - 10 IS - 6 PB - MDPI ER - TY - JOUR A1 - Bedbur, Stefan A1 - Kamps, Udo A1 - Schmiedt, Anja Bettina T1 - A flexible model of ordered random variables for non-metallic inclusions in steels and related statistical inference JF - Applied Mathematical Modelling N2 - In a data set of non-metallic inclusion sizes in samples from engineering steel, common order statistics fail to serve as a suitable model for ascendingly ordered measurements within single samples. Therefore, a flexible model of ordered random variables is proposed, which allows for changes of distributions described by model parameters. Joint maximum likelihood estimation of these parameters and the shape parameter of an underlying left-truncated Weibull distribution is considered, and a model test is developed for the null-hypothesis of common order statistics being an adequate model. To overcome small data situations, a link-function approach is examined in order to reduce the number of involved model parameters as well as to propose to use a link-function parameter as a material indicator. An asymptotic test is provided to check for the presence of a linear link function, and tests for hypotheses about two link-function parameters are studied. Moreover, the construction of simultaneous confidence regions for the link-function parameters as well as of confidence bands for the entire graph of the link function are presented. Throughout, the findings are applied to the real metallurgical data set. Similar problems and data structures arise in other fields of material science and applications such as geology. Y1 - 2026 U6 - https://doi.org/10.1016/j.apm.2025.116284 SN - 0307-904X N1 - Corresponding author der OTH Regensburg: Anja Bettina Schmiedt VL - 149 PB - Elsevier ER - TY - JOUR A1 - Schumm, Leon A1 - Brown, Tom A1 - Abdel-Khalek, Hazem A1 - Ueckerdt, Falko A1 - Sterner, Michael A1 - Fioriti, David A1 - Parzen, Max T1 - The impact of temporal hydrogen regulation on hydrogen exporters and their domestic energy transition JF - Nature Communications N2 - As global demand for green hydrogen rises, potential hydrogen exporters move into the spotlight. While exports can bring countries revenue, large-scale on-grid hydrogen electrolysis for export can profoundly impact domestic energy prices and energy-related emissions. Our investigation explores the interplay of hydrogen exports, domestic energy transition and temporal hydrogen regulation, employing a sector-coupled energy model in Morocco. We find substantial co-benefits of domestic carbon dioxide mitigation and hydrogen exports, whereby exports can reduce market-based costs for domestic electricity consumers while mitigation reduces costs for hydrogen exporters. However, increasing hydrogen exports in a fossil-dominated system can substantially raise market-based costs for domestic electricity consumers, but surprisingly, temporal matching of hydrogen production can lower these costs by up to 31% with minimal impact on exporters. Here, we show that this policy instrument can steer the welfare (re-)distribution between hydrogen exporting firms, hydrogen importers, and domestic electricity consumers and hereby increases acceptance among actors. KW - Energy Transition KW - Hydrogen regulation Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-84857 N1 - Die Preprint-Version ist ebenfalls in diesem Repositorium verzeichnet unter: https://opus4.kobv.de/opus4-oth-regensburg/7272 VL - 16 PB - Nature CY - London ER - TY - JOUR A1 - Schmiedt, Anja B. A1 - Empacher, Christina A1 - Kamps, Udo T1 - One- and two-sided prediction intervals for future Pareto record values with applications JF - Journal of Statistical Theory and Applications N2 - Based on upper record values in a series of observations over time from a Pareto distribution, an exact and several approximate one-sided and two-sided prediction intervals for the next record value (or for another future record value) to appear are studied and compared by means of an extensive simulation study. The performances of the prediction intervals are evaluated and recommendations are proposed for what method should be used in a given situation with respect to the form of the prediction interval on the one hand and to the tail behaviour on the other. The proposed methods are applied to insurance, environmental and sports data, where the respectively fitted Pareto distributions show a different tail behaviour. As a result, it is seen that although the number of observed record values in the presented real data applications is rather small, as it is usually the case, the selected prediction intervals are of practical use. KW - Interval prediction KW - Pareto distribution KW - Real data analyses KW - Record values KW - Simulation study Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-81605 SN - 2214-1766 N1 - Corresponding author der OTH Regensburg: Anja B. Schmiedt PB - Springer ER - TY - JOUR A1 - Dotter, Caroline A1 - Haug, Sonja A1 - Schnell, Rainer A1 - Raptis, Georgios A1 - Weber, Karsten T1 - Sharing health data for research purposes: results of a population survey in Germany JF - BMC health services research N2 - BACKGROUND: Increased use of health data has the potential to improve both health care and health policies. Several recent policy initiatives at the European and German legislative levels aim to increase the primary and secondary use of health data. However, little is known about general population views on health data access for research. Most studies are based on subsets defined by specific illnesses. METHODS: We commissioned a national computer-assisted dual-frame telephone survey (landline and mobile). Logit estimation models were used to identify predictors of willingness to provide access to health data to different organizations (universities in Germany, universities worldwide, German government organizations, pharmaceutical companies). RESULTS: A high willingness to share health data for research purposes is observed, depending on the specific data recipient. The willingness is highest for research at universities in Germany and German governmental organizations, and lowest regarding research by pharmaceutical companies. The main drivers for sharing health data are the level of trust in public institutions, the respondents' assessment of the seriousness and likelihood of data misuse, and the level of digital literacy. Age, gender, and level of education have small effects and do not determine the willingness to share health data for all organizations. CONCLUSION: We present evidence from a random sample of the German population. The results indicate widespread support among the population for providing access to health data for research purposes. Similar to findings in other countries, the willingness depends strongly on the recipient of the data. This paper evaluates the impact of various determinants - identified in previous qualitative and quantitative research - on the willingness of the German population to share health data. While previous studies have found that patients are generally more willing to share health data, we found that the presence of a medical precondition does not translate into respondents' unequivocal support for health data sharing. We identify privacy concerns, general trust, and digital literacy as key factors influencing the willingness to share health data. Therefore, policymakers and stakeholders need to ensure and communicate the necessary privacy protection measures to increase the willingness of the German population to share health data. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-81622 N1 - Corresponding author der OTH Regensburg: Caroline Dotter VL - 25 PB - BMC ER - TY - CHAP A1 - Bugl, Benedikt A1 - Schneider, Viola I. A1 - Sehr, Armin T1 - Vertical Sound Localization: Precision and Robustness to Reverberation in a Large-Scale Study T2 - Proceedings of the 11th Convention of the European Acoustics Association Forum Acusticum / EuroNoise 2025 // Málaga, Spain ; 23-26. June 2025 N2 - Vertical sound localization, the ability to perceive the elevation of a sound source, is a fundamental aspect of human auditory perception, yet it remains far less understood than horizontal localization. Existing studies rely on small sample sizes, limiting the generalizability of findings. The presented study bridges that gap by examining vertical sound localization and precision in a cohort exceeding 150 participants, making it the largest investigation of its kind to date.Participants were exposed to broadband noise stimuli from various elevations under controlled anechoic conditions. The elevation localization error was measured by comparing perceived sound source elevations to actual positions of speakers of a curved array. Azimuth angles of arrival were altered between 0°, 45° and 90°. For a small group the experiment was repeated in echoic conditions, to gain insight in reverberation and reflection robustness of vertical sound localization.This large-scale study establishes benchmarks for vertical sound localization precision and robustness, advancing our understanding of human auditory spatial perception. These findings have implications for audio technology development, such as spatial audio rendering and hearing aid design, and lay the groundwork for further exploration into the neural and anatomical underpinnings of vertical localization. Y1 - 2025 SN - 978-84-87985-35-5 U6 - https://doi.org/10.61782/fa.2025.0953 SP - 3431 EP - 3434 PB - European Acoustics Association ER - TY - CHAP A1 - Galka, Stefan A1 - Meißner, Sebastian T1 - Simulation-Based Digital Twins for Internal Transport Systems T2 - Procedia Computer Science N2 - The increasing complexity of internal transport systems in industrial applications poses significant challenges for operational decision-making. This paper presents a simulation-based Digital Twin framework developed within the research project TwinTraSys to support the control of such systems. The framework is specifically tailored to the constraints of real-world IT infrastructures, requiring minimal transaction data, while enabling predictive analysis and dynamic scenario evaluation. It consists of a modular architecture divided into four core components: data provision, data preparation, simulation, and decision support. A dedicated simulation framework enables the automated generation of structural models and the integration of real-world operational control systems. The proposed approach has been validated in industrial settings and has demonstrated its ability to support resource planning and transport resource allocation through simulation-based experimentation and multi-criteria evaluation. This paper contributes to the practical advancement of Digital Twin applications in intralogistics by bridging the gap between theoretical models and real-world constraints. KW - Digital Twin KW - Intralogistics KW - Logistics KW - Operational Control KW - Simulation KW - Simulation-based Decision Support Y1 - 2025 U6 - https://doi.org/10.1016/j.procs.2025.12.016 N1 - Corresponding author der OTH Regensburg: Stefan Galka VL - 274 SP - 161 EP - 170 PB - Elsevier ER - TY - JOUR A1 - Afanasev, Anna A1 - Höfer, Philipp A1 - Holtmannspötter, Jens A1 - Zimmer, Felix A1 - Ehrlich, Ingo T1 - Development of a continuous fiber-reinforced 3D printing process with a 6-axis robot arm: Process design and equipment JF - The International Journal of Advanced Manufacturing Technology N2 - The utilisation of 3D printing processes in the fabrication of continuous fiber-reinforced composites confers a multitude of advantages, in particular flexible design based on structural requirements. In order to achieve greater flexibility, there is a necessity for 3D printing systems that allow for customisable material selection and fiber positioning. This paper presents the design of a robot-based 3D printing system that incorporates an in-situ impregnation line and flexibility regarding the machine code generation for fiber positioning. The development of the system enabled the attainment of an average fiber volume content of up to 37.12%. In the tensile tests, material characteristics up to E1 = 24.7 GPa and strength of up to RM1 = 0.51 GPa were determined. Y1 - 2026 U6 - https://doi.org/10.1007/s00170-025-17263-3 SN - 0268-3768 N1 - Corresponding author der OTH Regensburg: Anna Afanasev PB - Springer ER - TY - JOUR A1 - Wolfgramm, Alex A1 - Abb, Valerius A1 - Samp, Artur A1 - Samp, Rafal A1 - Hoffmann, Jens Christoph A1 - Müller, Rainer A1 - Kammler, Martin T1 - Structural and functional evolution of HKUST-1 nanoparticles induced by ball milling JF - Next Materials N2 - In this study, the effect of post-synthetic ball milling on the structural and functional properties of as-synthesized nanoparticles of the copper-based metal-organic framework (MOF) HKUST-1 was investigated for the first time. Nanoparticles were synthesized using sodium formate as a capping agent. The crystalline particles were subjected to a controlled ball milling process, which induced significant structural changes. Powder X-ray diffraction (PXRD) revealed a reduction in crystallite size from 91 nm to 21 nm and the introduction of microstrain, partially disrupting the MOF's long-range crystalline order, as evidenced by peak broadening and the diminished intensity of high-angle reflections. Particle morphology pre- and post-milling was further studied with scanning electron microscopy (SEM) imaging, verifying a narrow particle size distribution of ± 22 nm after milling. Fourier-transform infrared spectroscopy (FTIR) indicated protonation of carboxylate groups in the larger pores of the framework, likely due to moisture incorporation during milling. Brunauer-Emmett-Teller (BET) surface area analysis showed a substantial decrease in specific surface area from 521 m²/g to 226 m²/g, suggesting a partial collapse of the porous framework. We discuss the applicability of ball milling as a versatile means of post-synthetic approach to reduce MOF particle sizes, a key element in the preparation of MOF-based thin films using inks or polymers. KW - Ball milling KW - Copper-based metal-organic framework KW - HKUST-1 KW - Nitrogen adsorption Y1 - 2026 U6 - https://doi.org/10.1016/j.nxmate.2025.101544 N1 - Corresponding author der OTH Regensburg: Alex Wolfgramm VL - 10 PB - Elsevier ER - TY - JOUR A1 - Schumm, Leon A1 - Haas, Jannik A1 - Peer, Rebecca A1 - Sterner, Michael T1 - The role of hydrogen offtaker regulation in highly renewable electricity systems JF - Energy N2 - The growing demand for green hydrogen necessitates a rapid scale-up of production and exports to meet decarbonization targets globally. However, current ramp-up efforts remain insufficient, calling for policies that unlock the potential of hydrogen as a low-carbon energy carrier. A key lever is the offtaker regulation, which impacts the pace and sustainability of export projects. This study investigates minimum renewable share requirements for hydrogen exports in countries with high renewable electricity shares. Using New Zealand as a case study, we develop a fully sector-coupled capacity expansion and dispatch model, integrating hydrogen and electricity network planning based on PyPSA-Earth. The model optimizes New Zealand’s energy system under varying export scenarios, renewable electricity shares, and resulting system impacts. We find that domestic electricity demand and renewable expansion rates dominate long-term outcomes, while progressive regulation enables short-term hydrogen and Power-to-X exports. Relaxing the renewable threshold from 80% to 60% triples export volumes from 2.5 TWh to 8.2 TWh by 2030. We propose a two-stage requirement: an initially progressive threshold to attract investment with low consequential emissions, followed by stricter regulation to prevent high emissions, rising domestic electricity prices, and declining hydrogen competitiveness. This framework, demonstrated for New Zealand, can guide hydrogen-exporting countries worldwide. KW - Climate neutrality KW - e-fuels KW - Emission intensity KW - Energy systems modelling KW - Hydrogen exports KW - Hydrogen offtaker regulation KW - Power-to-X Y1 - 2026 U6 - https://doi.org/10.1016/j.energy.2025.139513 N1 - Corresponding author der OTH Regensburg: Leon Schumm VL - 342 PB - Elsevier ER - TY - JOUR A1 - Heinz, Florian A1 - Schildgen, Johannes T1 - Experience Report: Hey LLM, Generate SQL! JF - Datenbank-Spektrum N2 - Large Language Models have advanced to a resourceful tool with many applications. One particularly interesting use case is the LLM-aided generation of ad-hoc database queries and the possibility of subsequent processing of the results in a way suiting the users intents. In this article, practical ways and experiences are described on how to effectively use LLMs to map a natural-language user query to an SQL query conforming to a specific database schema and post-processing the results of this query in order to, for example, create an appealing visualization. Best results are achieved under favorable circumstances, as, for example, a clean and meaningful named database schema. Y1 - 2025 U6 - https://doi.org/10.1007/s13222-025-00512-w N1 - Corresponding author der OTH Regensburg: Florian Heinz VL - 25 IS - 2 SP - 95 EP - 101 PB - Springer CY - Wiesbaden ER - TY - JOUR A1 - Hollweck, Christoph A1 - Leidinger, Lukas A1 - Hartmann, Stefan A1 - Wagner, Marcus A1 - Wüchner, Roland T1 - An analysis of the critical time step size for explicit dynamics using trimmed B-splines, LR-splines, and THB-splines JF - Computer Methods in Applied Mechanics and Engineering N2 - Isogeometric analysis (IGA) combined with explicit dynamics is increasingly used in academia and has already been successfully applied in industrial simulations, including crash and sheet-metal forming. Since explicit schemes are only conditionally stable, accurate estimation of the critical time step is essential for both stability and efficiency. Adaptive mesh refinement is widely used to balance accuracy and computational cost. In IGA, THB- and LR-splines break the tensor-product structure of standard B-splines and enable local refinement, but their effect on the critical time step under trimming has not been systematically studied - a key requirement for reliable time step estimation. We investigate the critical time step in explicit dynamic simulations using trimmed B-splines, LR-splines, and THB-splines, based on a lumped mass matrix obtained by simple row summation. One-dimensional bar, two-dimensional membrane, and trimmed shell models are analyzed to determine how trimming and local refinement influence element and system eigenfrequencies, which directly control the stable time step. Refined boundary elements in open knot vectors are identified as the main bottleneck. Trimming these elements can increase the stable time step, though certain trimming configurations introduce new restrictions. Results show that LR- and THB-splines impose time step constraints similar to B-splines, making them equally suitable for explicit simulations. We also present a general method for computing element-wise Bézier extraction operators for LR- and THB-splines, enabling straightforward integration into standard finite element solvers. The findings are validated through nonlinear sheet-metal forming simulations in LS-DYNA using shells discretized with trimmed B-, LR-, and THB-splines. This represents the first such application and demonstrates their practical feasibility for industrial use. Y1 - 2026 U6 - https://doi.org/10.1016/j.cma.2025.118656 SN - 0045-7825 N1 - Corresponding author der OTH Regensburg: Christoph Hollweck VL - 450 PB - Elsevier ER - TY - CHAP A1 - Albrecht, Sophie Viktoria A1 - Thiel, Charlotte A1 - Karamara, Merve T1 - Decoding concrete’s environmental performance: A detailed analysis of global EPDs across the entire life cycle T2 - MATEC Web of Conferences N2 - Environmental Product Declarations (EPDs) for concrete are essential tools to quantify the environmental impact of this versatile building material throughout its life cycle, supporting sustainable choices in construction. Concrete is made up of raw materials like cement, water, aggregates, additives, and admixtures, which can be mixed in diverse ways. This variability often necessitates site-specific EPDs, as emissions and environmental impacts depend greatly on cement type, transport routes, and specific production processes. This study analyses various data sources, focusing on EPDs according to ISO 14025 and EN 15804. The life cycle phases A1-A3, B1-B7, C1-C4 and D are considered and compared. The results demonstrate that factors such as scenario assumptions, methodological choices, and allocation procedures significantly influence concrete’s environmental impact. Transparent EPDs improve assessment reliability, while allocation methods, especially in phases D and end-of-life, significantly influence reported benefits, underscoring the importance of careful allocation for accurate impact evaluations. Improved standardisation, transparency, and alignment with EN 16757 would enhance EPD comparability and reliability. Overall, the study identifies key parameters such as recycling potential, production stage and allocation methods as substantial factors in the environmental performance of concrete. Y1 - 2025 U6 - https://doi.org/10.1051/matecconf/202540913001 VL - 409 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Qiao, Yu A1 - Grad, Marius A1 - Nonn, Aida T1 - Toward an Efficient and Robust Process–Structure Prediction Framework for Filigree L-PBF 316L Stainless Steel Structures JF - Metals N2 - Additive manufacturing (AM), particularly laser powder bed fusion (L-PBF), provides unmatched design flexibility for creating intricate steel structures with minimal post-processing. However, adopting L-PBF for high-performance applications is difficult due to the challenge of predicting microstructure evolution. This is because the process is sensitive to many parameters and has a complex thermal history. Thin-walled geometries present an added challenge because their dimensions often approach the scale of individual grains. Thus, microstructure becomes a critical factor in the overall integrity of the component. This study focuses on applying cellular automata (CA) modeling to establish robust and efficient process–structure relationships in L-PBF of 316L stainless steel. The CA framework simulates solidification-driven grain evolution and texture development across various processing conditions. Model predictions are evaluated against experimental electron backscatter diffraction (EBSD) data, with additional quantitative comparisons based on texture and morphology metrics. The results demonstrate that CA simulations calibrated with relevant process parameters can effectively reproduce key microstructural features, including grain size distributions, aspect ratios, and texture components, observed in thin-walled L-PBF structures. This work highlights the strengths and limitations of CA-based modeling and supports its role in reliably designing and optimizing complex L-PBF components. Y1 - 2025 U6 - https://doi.org/10.3390/met15070812 SN - 2075-4701 VL - 15 IS - 7 PB - MDPI ER - TY - JOUR A1 - Rueckert, Tobias A1 - Rauber, David A1 - Maerkl, Raphaela A1 - Klausmann, Leonard A1 - Yildiran, Suemeyye R. A1 - Gutbrod, Max A1 - Nunes, Danilo Weber A1 - Moreno, Alvaro Fernandez A1 - Luengo, Imanol A1 - Stoyanov, Danail A1 - Toussaint, Nicolas A1 - Cho, Enki A1 - Kim, Hyeon Bae A1 - Choo, Oh Sung A1 - Kim, Ka Young A1 - Kim, Seong Tae A1 - Arantes, Gonçalo A1 - Song, Kehan A1 - Zhu, Jianjun A1 - Xiong, Junchen A1 - Lin, Tingyi A1 - Kikuchi, Shunsuke A1 - Matsuzaki, Hiroki A1 - Kouno, Atsushi A1 - Manesco, João Renato Ribeiro A1 - Papa, João Paulo A1 - Choi, Tae-Min A1 - Jeong, Tae Kyeong A1 - Park, Juyoun A1 - Alabi, Oluwatosin A1 - Wei, Meng A1 - Vercauteren, Tom A1 - Wu, Runzhi A1 - Xu, Mengya A1 - Wang, An A1 - Bai, Long A1 - Ren, Hongliang A1 - Yamlahi, Amine A1 - Hennighausen, Jakob A1 - Maier-Hein, Lena A1 - Kondo, Satoshi A1 - Kasai, Satoshi A1 - Hirasawa, Kousuke A1 - Yang, Shu A1 - Wang, Yihui A1 - Chen, Hao A1 - Rodríguez, Santiago A1 - Aparicio, Nicolás A1 - Manrique, Leonardo A1 - Palm, Christoph A1 - Wilhelm, Dirk A1 - Feussner, Hubertus A1 - Rueckert, Daniel A1 - Speidel, Stefanie A1 - Nasirihaghighi, Sahar A1 - Al Khalil, Yasmina A1 - Li, Yiping A1 - Arbeláez, Pablo A1 - Ayobi, Nicolás A1 - Hosie, Olivia A1 - Lyons, Juan Camilo T1 - Comparative validation of surgical phase recognition, instrument keypoint estimation, and instrument instance segmentation in endoscopy: Results of the PhaKIR 2024 challenge JF - Medical Image Analysis N2 - Reliable recognition and localization of surgical instruments in endoscopic video recordings are foundational for a wide range of applications in computer- and robot-assisted minimally invasive surgery (RAMIS), including surgical training, skill assessment, and autonomous assistance. However, robust performance under real-world conditions remains a significant challenge. Incorporating surgical context – such as the current procedural phase – has emerged as a promising strategy to improve robustness and interpretability. To address these challenges, we organized the Surgical Procedure Phase, Keypoint, and Instrument Recognition (PhaKIR) sub-challenge as part of the Endoscopic Vision (EndoVis) challenge at MICCAI 2024. We introduced a novel, multi-center dataset comprising thirteen full-length laparoscopic cholecystectomy videos collected from three distinct medical institutions, with unified annotations for three interrelated tasks: surgical phase recognition, instrument keypoint estimation, and instrument instance segmentation. Unlike existing datasets, ours enables joint investigation of instrument localization and procedural context within the same data while supporting the integration of temporal information across entire procedures. We report results and findings in accordance with the BIAS guidelines for biomedical image analysis challenges. The PhaKIR sub-challenge advances the field by providing a unique benchmark for developing temporally aware, context-driven methods in RAMIS and offers a high-quality resource to support future research in surgical scene understanding. KW - Surgical phase recognition KW - Instrument keypoint estimation KW - Instrument instance segmentation KW - Robot-assisted surgery Y1 - 2026 U6 - https://doi.org/10.1016/j.media.2026.103945 SN - 1361-8415 N1 - Corresponding author der OTH Regensburg: Tobias Rueckert Die Preprint-Version ist ebenfalls in diesem Repositorium verzeichnet unter: https://opus4.kobv.de/opus4-oth-regensburg/solrsearch/index/search/start/0/rows/10/sortfield/score/sortorder/desc/searchtype/simple/query/2507.16559 VL - 109 PB - Elsevier ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform JF - Sensors N2 - In this work, multiferroic cantilevers comprise a layer of a magnetoactive elastomer (MAE) and a commercially available piezoelectric polymer-based vibration sensor. The structures are fixed at one end in the horizontal plane and the magnetic field is applied vertically. First, the magnetoelectric (ME) response to uniform, triangle-wave magnetic fields with five different slew rates is investigated experimentally. Time and field dependences of the generated voltage, electric charge, and observed mechanical deflection are obtained and compared for four different thicknesses of the MAE layer. The ME responses to triangular and sinusoidal wave excitations are examined in contrast. Second, the ME response at low frequencies (≤3 Hz) is studied by the standard method of harmonic magnetic field modulation. The highest ME coupling coefficient is observed in the bias magnetic field strength of ≈73 kA/m and it is estimated to be about 3.3 ns/m (ME voltage coefficient ≈ 25 V/A) at theoretically vanishing modulation frequency (f→0 Hz). Presented results demonstrate that the investigated heterostructures are promising for applications as magnetic-field sensors and energy harvesting devices. KW - magnetoactive elastomer KW - piezoelectric polymer KW - multilayer cantilever KW - direct magnetoelectric effect KW - magnetic field sensing Y1 - 2022 U6 - https://doi.org/10.3390/s22103791 N1 - Corresponding authors: Gašper Glavan und Mikhail Shamonin Veröffentlichtes Datenset: https://doi.org/10.5281/zenodo.14651784 VL - 22 IS - 10 SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kuettner, Andreas A1 - Fischer, Samuel A1 - Laumer, Tobias T1 - Mechanical and structural characterization of heat-staked parts realized by selective laser sintering of polyamide 12 JF - The International Journal of Advanced Manufacturing Technology N2 - Heat staking is a joining process in which thermoplastic pins are formed by heat and pressure in a form-fitting and insoluble way. This study evaluates the mechanical performance and microstructure of selective laser sintered (SLS) polyamide 12 (PA 12) components before and after heat staking, compared with conventionally turned reference specimens. The components were characterized using tensile tests, micrographs, microscopy, and micro-CT measurements. For the tests, the forces and temperatures during heat staking were varied to determine the best process parameters. Tensile tests revealed that SLS joints achieved strengths of up to 33.6 MPa, approaching the 39.9 MPa of the turned references. Microstructural analysis showed a marked reduction in porosity due to heat staking. Porosity decreased from 3.9% to 1.56% at a staking force of 300 N and from 4.29% to 0.81% at 1000 N, highlighting the beneficial effect of increased force. These results demonstrate that heat staking parameters significantly influence local densification and mechanical performance, and that, under suitable conditions, SLS components can achieve joint strengths comparable to conventionally manufactured parts. The study shows that the heat staking process parameters have a significant influence on the local microstructure and thus on the mechanical performance and provides a basis for optimizing SLS components for new heat staking applications. KW - Additive manufacturing KW - Heat staking KW - Material qualification KW - Polyamid 12 (PA) KW - Selective laser sintering (SLS) Y1 - 2026 U6 - https://doi.org/10.1007/s00170-025-17319-4 PB - Springer ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields JF - Polymers N2 - Significant deformations of bodies made from compliant magnetoactive elastomers (MAE) in magnetic fields make these materials promising for applications in magnetically controlled actuators for soft robotics. Reported experimental research in this context was devoted to the behaviour in the quasi-static magnetic field, but the transient dynamics are of great practical importance. This paper presents an experimental study of the transient response of apparent longitudinal and transverse strains of a family of isotropic and anisotropic MAE cylinders with six different aspect ratios in time-varying uniform magnetic fields. The time dependence of the magnetic field has a trapezoidal form, where the rate of both legs is varied between 52 and 757 kA/(s·m) and the maximum magnetic field takes three values between 153 and 505 kA/m. It is proposed to introduce four characteristic times: two for the delay of the transient response during increasing and decreasing magnetic field, as well as two for rise and fall times. To facilitate the comparison between different magnetic field rates, these characteristic times are further normalized on the rise time of the magnetic field ramp. The dependence of the normalized characteristic times on the aspect ratio, the magnetic field slew rate, maximum magnetic field values, initial internal structure (isotropic versus anisotropic specimens) and weight fraction of the soft-magnetic filler are obtained and discussed in detail. The normalized magnetostrictive hysteresis loop is introduced, and used to explain why the normalized delay times vary with changing experimental parameters. KW - magnetoactive elastomer KW - magnetorheological elastomer KW - macroscopic deformation KW - magnetostriction KW - time-varying magnetic field Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-71067 SN - 2073-4360 N1 - Corresponding author der OTH Regensburg: Gašper Glavan Zugehöriges Datenset: doi:10.5281/zenodo.10679499 VL - 16 IS - 5, Special Issue Magnetic Polymer Composites: Design and Application II PB - MDPI CY - Basel, Schweiz ER -