@article{GaertnerMarxSchubachGadereretal., author = {G{\"a}rtner, Sebastian and Marx-Schubach, Thomas and Gaderer, Matthias and Schmitz, Gerhard and Sterner, Michael}, title = {Techno-Economic Analysis of Carbon Dioxide Separation for an Innovative Energy Concept towards Low-Emission Glass Melting}, series = {energies}, volume = {16}, journal = {energies}, number = {5}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/en16052140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-53627}, pages = {1 -- 25}, abstract = {The currently still high fossil energy demand is forcing the glass industry to search for innovative approaches for the reduction in CO2 emissions and the integration of renewable energy sources. In this paper, a novel power-to-methane concept is presented and discussed for this purpose. A special focus is on methods for the required CO2 capture from typical flue gases in the glass industry, which have hardly been explored to date. To close this research gap, process simulation models are developed to investigate post-combustion CO2 capture by absorption processes, followed by a techno-economic evaluation. Due to reduced flue gas volume, the designed CO2 capture plant is found to be much smaller (40 m3 absorber column volume) than absorption-based CO2 separation processes for power plants (12,560 m3 absorber column volume). As there are many options for waste heat utilization in the glass industry, the waste heat required for CO2 desorption can be generated in a particularly efficient and cost-effective way. The resulting CO2 separation costs range between 41 and 42 EUR/t CO2, depending on waste heat utilization for desorption. These costs are below the values of 50-65 EUR/t CO2 for comparable industrial applications. Despite these promising economic results, there are still some technical restrictions in terms of solvent degradation due to the high oxygen content in flue gas compositions. The results of this study point towards parametric studies for approaching these issues, such as the use of secondary and tertiary amines as solvents, or the optimization of operating conditions such as stripper pressure for further cost reductions potential.}, language = {en} } @article{ZacherlWopperSchwanzeretal., author = {Zacherl, Florian and Wopper, Christoph and Schwanzer, Peter and Rabl, Hans-Peter}, title = {Potential of the Synthetic Fuel Oxymethylene Ether (OME) for the Usage in a Single-Cylinder Non-Road Diesel Engine: Thermodynamics and Emissions}, series = {Energies}, volume = {15}, journal = {Energies}, number = {21}, publisher = {MDPI}, doi = {10.3390/en15217932}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-55350}, pages = {1 -- 26}, abstract = {Non-road sectors, such as agriculture and construction machinery, require high energy densities and flexibility in use, which is why diesel engines are mainly used. The use of climate-neutral fuels, produced from renewable energies, such as Oxymethylene Ether (OME) as a diesel substitute, can significantly reduce CO2 and pollutant emissions in these sectors. In addition to CO2 neutrality, OME also offers improved combustion characteristics compared to diesel fuel, eliminating the soot-NOx trade-off and thus enabling new opportunities in engine design and calibration. In this paper, the combustion of pure OME on a close-to-production, single-cylinder non-road diesel engine with a pump-line-nozzle injection system is analyzed. A variation of the center of combustion at constant power output was performed for diesel and OME at different operating points. Two injectors were investigated with OME. A study on ignition delay and a detailed thermodynamic analysis was carried out. In addition, the exhaust emissions CO, NOx, VOC, as well as particulate-matter, -number and -size distributions were measured. With OME, a significantly shorter ignition delay as well as a shortened combustion duration could be observed, despite a longer injection duration. In addition, the maximum injection pressure increases. VOC and CO emissions are reduced. Particulate matter was reduced by more than 99\% and particle number (>10 nm) was reduced by multiple orders of magnitude. The median of the particle size distribution shifts from 60 to 85 nm (diesel) into a diameter range of sub 23 nm (OME). A significant reduction of NOx emissions with OME enables new degrees of freedom in engine calibration and an efficiency advantage without hardware adaption.}, language = {en} } @article{TroidlSchrollDecker, author = {Troidl, Kilian and Schroll-Decker, Irmgard}, title = {Wie theoriebasiert sind Forschungsbeitr{\"a}ge zur Bildungsbeteiligung? Eine Qualitative Inhaltsanalyse ausgew{\"a}hlter Fachzeitschriften der Erwachsenen- und Weiterbildungsforschung}, series = {Zeitschrift f{\"u}r Weiterbildungsforschung}, volume = {45}, journal = {Zeitschrift f{\"u}r Weiterbildungsforschung}, publisher = {Springer Nature}, doi = {10.1007/s40955-022-00229-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-55460}, pages = {19}, abstract = {In der Vergangenheit wurde beklagt, dass in der empirischen Forschung zur Bildungsbeteiligung Erwachsener selten eine Integration von Theorie und Empirie erfolge und die mangelnde empirische Pr{\"u}fung eine theoretische Weiterentwicklung des Forschungsfeldes erschwere. Mittels einer Qualitativen Inhaltsanalyse von Beitr{\"a}gen ausgew{\"a}hlter Fachzeitschriften der Erwachsenen‑/Weiterbildungsforschung wurde versucht, die Aktualit{\"a}t dieser Feststellung empirisch zu {\"u}berpr{\"u}fen. Dazu wurden 38 empirische Forschungsbeitr{\"a}ge zur Bildungsbeteiligung der Jahrg{\"a}nge 2018 bis 2020 von neun Fachzeitschriften mit Peer-Review untersucht. Die Einsch{\"a}tzung der Beitr{\"a}ge erfolgte hinsichtlich des Grades der Theorieeinbindung. Die Ergebnisse der Analyse zeigen ein gemischtes Bild: neun Beitr{\"a}ge (24 \%) binden keine Theorie in den Forschungsprozess ein, ein Beitrag (3 \%) zitiert Theorie lediglich, ohne sie weiter einzubinden. Am h{\"a}ufigsten ist eine Einbindung zum theoriegeleiteten Vorgehen (16 Beitr{\"a}ge, 42 \%). Eine tiefergehende Theorieanwendung findet sich in sechs Beitr{\"a}gen (16 \%). Eine theoriepr{\"u}fende oder -bildende Einbindung liegt mit je drei Beitr{\"a}gen (je 8 \%) seltener vor. Die rezipierten Theorien sind vielf{\"a}ltig: es werden 20 verschiedene Theorieans{\"a}tze festgestellt. Den Forderungen nach einer verst{\"a}rkten Einbindung von Theorie in den Forschungsprozess kann somit weiterhin G{\"u}ltigkeit attestiert werden: ein substanzieller Teil der Beitr{\"a}ge berichtet keine Theorieeinbindung, eine empirische Pr{\"u}fung oder Weiterentwicklung findet relativ selten statt.}, subject = {Erwachsenenbildung}, language = {de} } @article{SchoenbergerScherzingerMauerer, author = {Sch{\"o}nberger, Manuel and Scherzinger, Stefanie and Mauerer, Wolfgang}, title = {Ready to Leap (by Co-Design)? Join Order Optimisation on Quantum Hardware}, series = {Proceedings of the ACM on Management of Data, PACMMOD}, volume = {1}, journal = {Proceedings of the ACM on Management of Data, PACMMOD}, number = {1}, publisher = {ACM}, address = {New York, NY,}, doi = {10.1145/3588946}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-56634}, pages = {1 -- 27}, abstract = {The prospect of achieving computational speedups by exploiting quantum phenomena makes the use of quantum processing units (QPUs) attractive for many algorithmic database problems. Query optimisation, which concerns problems that typically need to explore large search spaces, seems like an ideal match for the known quantum algorithms. We present the first quantum implementation of join ordering, which is one of the most investigated and fundamental query optimisation problems, based on a reformulation to quadratic binary unconstrained optimisation problems. We empirically characterise our method on two state-of-the-art approaches (gate-based quantum computing and quantum annealing), and identify speed-ups compared to the best know classical join ordering approaches for input sizes that can be processed with current quantum annealers. However, we also confirm that limits of early-stage technology are quickly reached. Current QPUs are classified as noisy, intermediate scale quantum computers (NISQ), and are restricted by a variety of limitations that reduce their capabilities as compared to ideal future quantum computers, which prevents us from scaling up problem dimensions and reaching practical utility. To overcome these challenges, our formulation accounts for specific QPU properties and limitations, and allows us to trade between achievable solution quality and possible problem size. In contrast to all prior work on quantum computing for query optimisation and database-related challenges, we go beyond currently available QPUs, and explicitly target the scalability limitations: Using insights gained from numerical simulations and our experimental analysis, we identify key criteria for co-designing QPUs to improve their usefulness for join ordering, and show how even relatively minor physical architectural improvements can result in substantial enhancements. Finally, we outline a path towards practical utility of custom-designed QPUs.}, language = {en} } @article{KaessStrahringerWestner, author = {K{\"a}ss, Sebastian and Strahringer, Susanne and Westner, Markus}, title = {Practitioners' Perceptions on the Adoption of Low Code Development Platforms}, series = {IEEE Access}, journal = {IEEE Access}, publisher = {IEEE}, issn = {2169-3536}, doi = {10.1109/ACCESS.2023.3258539}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59170}, pages = {30}, abstract = {Organizations are under increasing pressure to develop applications within budget and time at high quality. Therefore, multiple organizations adopt Low Code Development Platforms (LCDP) to develop applications faster and cheaper compared to traditional application development. However, current research on LCDP adoption lacks empirical grounding as well as a deeper understanding of the importance of adoption drivers and inhibitors. We conducted semi-structured interviews and a Delphi study with seventeen experts to address these gaps. As a result, we identified twelve drivers and nineteen inhibitors for adopting LCDPs. We show that the experts have a consensus on the most and the least important drivers and inhibitors for LCDP adoption. Yet, the ranking of the drivers and inhibitors between the most and least important is highly context dependent. For some drivers and inhibitors, the experts' ranking is similar to academic literature, whereas, for others, it differs. In conclusion, the study at hand empirically validates drivers and inhibitors for LCDP adoption, adds six new drivers and six new inhibitors to the body of knowledge, and analyses the importance of these factors.}, language = {en} } @article{DotterHaugWeberetal., author = {Dotter, Caroline and Haug, Sonja and Weber, Karsten and Schnell, Rainer and Scharf, Anna and Altenburcher, Amelie}, title = {Analyzing factors determining vaccination willingness against COVID-19 in Germany 2020}, series = {Vaccine: X}, volume = {14}, journal = {Vaccine: X}, publisher = {Elsevier}, doi = {10.1016/j.jvacx.2023.100342}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-62900}, pages = {6}, abstract = {The study is based on a German single-topic population survey on vaccination willingness against COVID-19 (VWC) by the authors (2020, n = 2014). The single-topic survey allowed us to test several competing explanations for VWC, as discussed in the literature. The VWC in the sample was 67.3\%. Logistic regression was used to identify factors affecting VWC. Being at high risk from COVID-19 and having received flu vaccination have a positive impact on VWC. Perceived VWC of friends has a strong positive effect on respondents' VWC. Bivariate relationships of gender, age, and level of education with VWC were no longer significant in a multivariate analysis. Trust in alternative medicine and belief in conspiracy theories have a negative effect on VWC.}, language = {en} } @article{PangerlSukulRuecketal., author = {Pangerl, Jonas and Sukul, Pritam and R{\"u}ck, Thomas and Fuchs, Patricia and Weigl, Stefan and Miekisch, Wolfram and Bierl, Rudolf and Matysik, Frank-Michael}, title = {An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone}, series = {Photoacoustics}, volume = {38}, journal = {Photoacoustics}, publisher = {Elsevier}, issn = {2213-5979}, doi = {10.1016/j.pacs.2024.100604}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-71279}, pages = {12}, abstract = {n this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) - providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm 1Hz 0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.}, language = {en} } @article{AlbrechtHellerbrandWeiningeretal., author = {Albrecht, Sophie Viktoria and Hellerbrand, Stefan and Weininger, Florian and Thiel, Charlotte}, title = {Strategies for Minimizing Environmental Impact in Construction: A Case Study of a Cementitious 3D Printed Lost Formwork for a Staircase}, series = {materials}, volume = {18}, journal = {materials}, publisher = {MDPI}, doi = {10.3390/ma18040825}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79236}, pages = {18}, abstract = {The construction industry faces significant challenges, including environmental sustainability, rising material costs, and a shortage of skilled labor. Digital fabrication technologies offer innovative solutions to address these issues by reducing raw material consumption and waste generation. Among these, 3D printing technologies offer distinct advantages over traditional construction methods, particularly in handling complex geometries. However, the significant environmental impact of cement in 3D printed concrete, due to its high rheological and printability requirements, remains a concern. This study introduces a novel application of 3D printed permanent formwork in the construction of a winder staircase, assessed through an Environmental Life Cycle Assessment (LCA) from cradle to gate. By comparing the environmental impacts of various construction materials and processes, this study highlights the comparative advantages and disadvantages of conventional methods versus 3D printing. The LCA results reveal that traditional production methods, particularly those using plywood formwork, exhibit higher environmental impacts. In contrast, timber formwork performs better than most 3D printed mixtures in terms of Global Warming Potential (GWP), Acidification Potential (AP), and abiotic depletion potential (ADP). The findings of this study underscore the potential of additive manufacturing for sustainable construction, particularly through the use of low-clinker cement in 3D printed formwork, offering a promising pathway towards reducing the environmental footprint of construction activities}, language = {en} } @article{WestnerReichenederMatschi, author = {Westner, Markus and Reicheneder, Matthias and Matschi, Markus}, title = {From Captive Centers to Global Integration}, series = {Information Resources Management Journal}, volume = {38}, journal = {Information Resources Management Journal}, number = {1}, publisher = {IGI Global}, issn = {1533-7979}, doi = {10.4018/IRMJ.373322}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-80406}, pages = {25}, abstract = {Contemporary developments in virtual work and global talent management are transforming information technology (IT) nearshoring and offshoring practices, yet research on organizational responses remains limited. Through expert interviews with 33 IT executives (76\% chief information officers) from Germany's top 500 companies, this article examines organizational models, strategies, and good practices in IT nearshoring and offshoring. It reveals a shift from traditional captive centers toward fully integrated global teams, enabling high-value task delivery and reflecting increased workforce maturity. Companies are expanding their operations driven by talent needs rather than cost savings, with success factors including employee integration and robust on-site management. This study contributes to theory and practice by providing a framework for understanding organizational models in global IT delivery and offering actionable insights for executives, emphasizing workforce integration over geographical separation.}, subject = {Offshoring}, language = {en} } @article{HauslerHolznerEhrnspergeretal., author = {Hausler, Peter and Holzner, Lukas and Ehrnsperger, Matthias and Bierl, Rudolf}, title = {Evaluation of the creep strength of samples produced by fused deposition modeling}, series = {Open Engineering}, volume = {14}, journal = {Open Engineering}, number = {1}, publisher = {de Gruyter}, doi = {10.1515/eng-2024-0084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79760}, pages = {10}, abstract = {Data sheets for 3D printing materials typically include softening temperature, impact strength, tensile strength, and stiffness. However, creep strength, an important parameter for components used over an extended period, is usually not included. Nevertheless, this parameter is of significant importance for components that are used over an extended period of time.This study compares the long-term creep behavior of a selection of materials that are commonly used in fused deposition modeling 3D printing. The materials under investigation are acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polylactic acid, and polycarbonate. In addition, the influence of fiber reinforcements on these materials is also examined. A simple, reproducible test procedure is proposed for users to determine and compare creep resistance of materials. This enables developers to select materials suitable for their own requirements on creep resistance and allows 3D-printing users to compare different materials. Results suggest that fiber reinforcement generally improves creep stability in 3D-printing materials, with GreenTEC Pro Carbon and add:north PC Blend HT LCF showing the most promise in this study.}, language = {en} } @article{HaugSchnellRaptisetal., author = {Haug, Sonja and Schnell, Rainer and Raptis, Georgios and Dotter, Caroline and Weber, Karsten}, title = {Wissen und Einstellung zur Speicherung und Nutzung von Gesundheitsdaten: Ergebnisse einer Bev{\"o}lkerungsbefragung}, series = {Zeitschrift f{\"u}r Evidenz, Fortbildung und Qualit{\"a}t im Gesundheitswesen}, journal = {Zeitschrift f{\"u}r Evidenz, Fortbildung und Qualit{\"a}t im Gesundheitswesen}, publisher = {Elsevier}, issn = {1865-9217}, doi = {10.1016/j.zefq.2023.11.001}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-67461}, pages = {50 -- 58}, abstract = {Hintergrund/Zielsetzung Der Beitrag befasst sich mit dem Wissenstand und der Einstellung der Bev{\"o}lkerung. Betrachtet werden die {\"U}bermittlung und Verf{\"u}gbarkeit von Gesundheitsdaten, Gesundheitsregister, die elektronische Patientenakte, Einwilligungsverfahren f{\"u}r die {\"U}bermittlung von Daten und der Zugriff auf Gesundheitsdaten zu Forschungszwecken. Methoden Die Studie basiert auf einer computergest{\"u}tzten Telefonbefragung (Dual-Frame) bei einer Zufallsstichprobe der Bev{\"o}lkerung in Deutschland im Zeitraum 01.-27.06.2022 (n = 1.308). Ergebnisse Der Wissensstand zur {\"U}bermittlung von Gesundheitsdaten an Krankenkassen ist hoch, wohingegen das Vorhandensein zentraler Sterbe-, Impf- und Gesundheitsregister sowie der Zugriff auf Gesundheitsdaten durch behandelnde {\"A}rztinnen und {\"A}rzte {\"u}bersch{\"a}tzt werden. Die Akzeptanz medizinischer Register ist sehr hoch. Die elektronische Patientenakte ist bei der H{\"a}lfte der Bev{\"o}lkerung unbekannt, die Nutzungsbereitschaft ist eher gering ausgepr{\"a}gt; bei der {\"U}bertragung von Daten wird eine Zustimmungsoption bevorzugt, und {\"u}ber achtzig Prozent w{\"u}rden die Daten der elektronischen Patientenakte zur Forschung freigeben. Drei Viertel w{\"u}rden ihre Gesundheitsdaten allgemein zur Forschung freigeben, insbesondere an Universit{\"a}ten in Deutschland, wobei meist Anonymit{\"a}t Bedingung ist. Die Bereitschaft zur Datenfreigabe steigt mit der H{\"o}he des Vertrauens in die Presse sowie in Universit{\"a}ten und Hochschulen, und sie sinkt, wenn ein Datenleck als schwerwiegend erachtet wird. Diskussion und Schlussfolgerung In Deutschland besteht, wie in anderen europ{\"a}ischen L{\"a}ndern, eine große Bereitschaft zur Freigabe von Gesundheitsdaten zu Forschungszwecken. Dagegen ist der Wunsch zur Nutzung der elektronischen Patientenakte eher gering. Ebenso niedrig ist die Akzeptanz einer Widerspruchsoption, die jedoch als Voraussetzung f{\"u}r eine erfolgreiche Einf{\"u}hrung einer elektronischen Patientenakte gilt. Vertrauen in die Forschung und staatliche Stellen, die Gesundheitsdaten verarbeiten, sind zentrale Faktoren.}, language = {en} } @article{ScharfHaugRitthaleretal., author = {Scharf, Anna and Haug, Sonja and Ritthaler, Markus and Raptis, Georgios}, title = {Chancen und Herausforderungen der Digitalisierung bei der Rehabilitation - Ergebnisse einer Befragung von Rehabilitationseinrichtungen}, series = {Die Rehabilitation: Zeitschrift f{\"u}r Praxis und Forschung in der Rehabilitation}, volume = {62}, journal = {Die Rehabilitation: Zeitschrift f{\"u}r Praxis und Forschung in der Rehabilitation}, number = {5}, publisher = {Thieme}, address = {Stuttgart}, doi = {10.1055/a-2123-1566}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-64726}, pages = {299 -- 307}, abstract = {Ziel der Studie: Ziel der Studie ist die Messung des Stands der Digitalisierung und die mit einer Anbindung an die Telematikinfrastruktur verbundenen Chancen und Herausforderungen f{\"u}r Rehabilitationseinrichtungen. Methodik: Teilstandardisierte Online-Befragung bei Tr{\"a}gern von Rehabilitationseinrichtungen in Bayern (n=33). Der Fragebogen mit 36 Fragen beinhaltet eine leicht ver{\"a}nderte Skala auf Basis des „Electronic Medical Record Adoption Model (EMRAM)". Ergebnisse: Der Digitalisierungsgrad wurde in 70 Prozent der Rehabilitationseinrichtungen mit Stufe 0 angegeben (Stufenmodell bis 7). Die {\"U}bermittlung patientenbezogener Daten (Eingang und Ausgang) erfolgt h{\"a}ufig analog, wohingegen die Verarbeitung innerhalb der Einrichtung in vielen F{\"a}llen bereits {\"u}berwiegend digital ist. Beim Anschluss an die Telematikinfrastruktur wird hoher Aufwand bei der Installation, aber auch der Schulung des Personals und der Anpassung der Arbeitsorganisation gesehen. Schlussfolgerung: Durch {\"A}nderung der gesetzlich-finanziellen Lage in Deutschland er{\"o}ffnen sich f{\"u}r Rehabilitationseinrichtungen neue M{\"o}glichkeiten einer verst{\"a}rkten Digitalisierung. H{\"u}rden h{\"a}ngen mit Anforderungen an IT-Sicherheit, Schulung des Personals und sowie dem ebenfalls geringen Digitalisierungsstand bei Krankenh{\"a}usern und {\"A}rzt*innen sowie Patient*innen zusammen, die eine digitale Daten{\"u}bermittlung erschweren.}, language = {de} } @article{GradZentgrafSchultheissetal., author = {Grad, Marius and Zentgraf, Jan and Schultheiss, Ulrich and Esper, Lukas and Diemar, Andreas and Noster, Ulf and Spiess, Lothar}, title = {Effect of Carbon Content on the Phase Composition, Microstructure and Mechanical Properties of the TiC Layer Formed in Hot-Pressed Titanium-Steel Composites}, series = {Metals}, volume = {14}, journal = {Metals}, number = {9}, publisher = {MDPI AG}, issn = {2075-4701}, doi = {10.3390/met14090959}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-74617}, abstract = {During the hot pressing of pure titanium and different carbon steels in a temperature range of ϑ = 950-1050 °C, a compound layer up to dL≈10 μm thick is formed at the titanium-steel interface. With a higher carbon content of the used steel, the layer thickness increases. The carbon concentration within the layer is in the range of stoichiometry for TiC. Apart from TiC, no other phases can be detected by X-ray diffraction (XRD) measurements inside the formed layer. The calculation of the activation energy for the TiC layer formation is Q = 126.5-136.7 kJ mol-1 and is independent of the carbon content of the steel. The resulting microstructure has a grain size gradient, wherein the mechanical properties, such as hardness and Young's modulus, are almost constant. Statistical analysis using Response Surface Methodology (RSM) indicates that the carbon content of the steel has the most significant influence on layer thickness, followed by annealing temperature and annealing time. By selecting the appropriate carbon steel and the subsequent removal of the steel, it is possible to produce targeted TiC layers on titanium substrates, which holds enormous potential for this material in wear-intensive applications.}, language = {en} } @article{AuerKubowitschDendorfer, author = {Auer, Simon and Kubowitsch, Simone and Dendorfer, Sebastian}, title = {Kombinierter Einfluss von psychologischen und biomechanischen Faktoren auf die muskul{\"a}ren Belastungen beim Fußballspielen}, series = {Die Orthop{\"a}die}, volume = {52}, journal = {Die Orthop{\"a}die}, number = {11}, publisher = {Springer}, doi = {10.1007/s00132-023-04437-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65113}, pages = {1 -- 6}, abstract = {When mental stress and musculoskeletal loading interact, the risk for injury increases due to altered body kinematics and increased muscle tension. These changes can be detected with musculoskeletal models, and mental loading and stress must be analyzed at emotional, cognitive, and behavioral levels. To investigate these kinematic and loading changes under stress, competitive athletes were subjected to mental stress during highly dynamic movements, and musculoskeletal models were used to analyze the biomechanical loading. It was shown that under mental stress, independent of the subjective perception, a strong change in muscle forces can occur. Accordingly, competitive athletes should undergo screenings to assess individual movement patterns and promote general stress resilience.}, language = {de} } @article{AuerSuessDendorfer, author = {Auer, Simon and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Using markerless motion capture and musculoskeletal models: An evaluation of joint kinematics}, series = {Technology and Health Care}, journal = {Technology and Health Care}, publisher = {IOS Press}, issn = {0928-7329}, doi = {10.3233/THC-240202}, pages = {1 -- 10}, abstract = {BACKGROUND: This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. OBJECTIVE: Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. METHODS: Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. RESULTS: The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. CONCLUSION: Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models.}, language = {en} } @article{KoeckStrieglKrausetal., author = {K{\"o}ck, Hannah and Striegl, Birgit and Kraus, Annalena and Zborilova, Magdalena and Christiansen, Silke H. and Sch{\"a}fer, Nicole and Gr{\"a}ssel, Susanne and Hornberger, Helga}, title = {In Vitro Analysis of Human Cartilage Infiltrated by Hydrogels and Hydrogel-Encapsulated Chondrocytes}, series = {Bioengineering}, volume = {10}, journal = {Bioengineering}, publisher = {MDPI}, doi = {10.3390/bioengineering10070767}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-61235}, pages = {1 -- 21}, abstract = {Osteoarthritis (OA) is a degenerative joint disease causing loss of articular cartilage and structural damage in all joint tissues. Given the limited regenerative capacity of articular cartilage, methods to support the native structural properties of articular cartilage are highly anticipated. The aim of this study was to infiltrate zwitterionic monomer solutions into human OA-cartilage explants to replace lost proteoglycans. The study included polymerization and deposition of methacryloyloxyethyl-phosphorylcholine- and a novel sulfobetaine-methacrylate-based monomer solution within ex vivo human OA-cartilage explants and the encapsulation of isolated chondrocytes within hydrogels and the corresponding effects on chondrocyte viability. The results demonstrated that zwitterionic cartilage-hydrogel networks are formed by infiltration. In general, cytotoxic effects of the monomer solutions were observed, as was a time-dependent infiltration behavior into the tissue accompanied by increasing cell death and penetration depth. The successful deposition of zwitterionic hydrogels within OA cartilage identifies the infiltration method as a potential future therapeutic option for the repair/replacement of OA-cartilage extracellular suprastructure. Due to the toxic effects of the monomer solutions, the focus should be on sealing the OA-cartilage surface, instead of complete infiltration. An alternative treatment option for focal cartilage defects could be the usage of monomer solutions, especially the novel generated sulfobetaine-methacrylate-based monomer solution, as bionic for cell-based 3D bioprintable hydrogels.}, language = {en} } @article{LooNagarajuPathivadaetal., author = {Loo, Xuyan and Nagaraju, Bhavana and Pathivada, Sai and Bartsch, Alexander and Schratzenstaller, Thomas and Sattler, Robert and Monkman, Gareth J.}, title = {Electrical properties of bisphenol-A-free magnetoactive borosilicate polymers}, series = {AIP Advances}, volume = {14}, journal = {AIP Advances}, number = {5}, publisher = {AIP Publishing}, issn = {2158-3226}, doi = {10.1063/5.0203017}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72936}, abstract = {The recent REACH regulations require the elimination of bisphenol-A and titanium dioxide from commercially available boron-based polymers. This has led to changes in some of the mechanical characteristics, which strongly influence the properties of magnetoactive borosilicate polymers. This work delivers results on the electrical properties and discusses some implications for future research using bisphenol-A and titanium-dioxide-free substitutes.}, language = {en} } @article{ZentgrafNuetzelMuehlbaueretal., author = {Zentgraf, Jan and N{\"u}tzel, Florian and M{\"u}hlbauer, Nico and Schultheiss, Ulrich and Grad, Marius and Schratzenstaller, Thomas}, title = {Surface Treatment of Additively Manufactured Polyetheretherketone (PEEK) by Centrifugal Disc Finishing Process: Identification of the Key Parameters}, series = {Polymers}, volume = {16}, journal = {Polymers}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym16162348}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-73959}, abstract = {Polyetheretherketone is a promising material for implants due to its good mechanical properties and excellent biocompatibility. Its accessibility to a wide range of applications is facilitated by the ability to process it with an easy-to-use manufacturing process such as fused filament fabrication. The elimination of disadvantages associated with the manufacturing process, such as a poor surface quality, is a main challenge to deal with. As part of the mass finishing process, centrifugal disc finishing has demonstrated good results in surface optimization, making it a promising candidate for the post-processing of additively manufactured parts. The objective of this study is to identify the key parameters of the centrifugal disc finishing process on the waviness of additively manufactured PEEK specimens, which has not been investigated previously. The waviness of the specimen was investigated by means of confocal laser scanning microscopy (CLSM), while weight loss was additionally tracked. Six parameters were investigated: type, amount and speed of media, use of compound, amount of water and time. Type of media, time and speed were found to significantly influence waviness reduction and weight loss. Surface electron microscopy images demonstrated the additional effects of deburring and corner rounding. Results on previous studies with specimens made of metal showed similar results. Further investigation is required to optimize waviness reduction and polish parts in a second post-processing step.}, language = {en} } @article{TauwaldErzingerQuadrioetal., author = {Tauwald, Sandra Melina and Erzinger, Florian and Quadrio, Maurizio and R{\"u}tten, Markus and Stemmer, Christian and Krenkel, Lars}, title = {Tomo-PIV in a patient-specific model of human nasal cavities: a methodological approach}, series = {Measurement Science and Technology}, volume = {35}, journal = {Measurement Science and Technology}, number = {5}, publisher = {IOP Publishing}, doi = {10.1088/1361-6501/ad282c}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-70393}, abstract = {The human nose serves as the primary gateway for air entering the respiratory system and plays a vital role in breathing. Nasal breathing difficulties are a significant health concern, leading to substantial healthcare costs for patients. Understanding nasal airflow dynamics is crucial for comprehending respiratory mechanisms. This article presents a detailed study using tomo-Particle Image Velocimetry (PIV) to investigate nasal airflow dynamics while addressing its accuracy. Embedded in the OpenNose project, the work described aims to provide a validation basis for different numerical approaches to upper airway flow. The study includes the manufacturing of a transparent silicone model based on a clinical CT scan, refractive index matching to minimize optical distortions, and precise flow rate adjustments based on physiological breathing cycles. This method allows for spatial high-resolution investigations in different regions of interest within the nasopharynx during various phases of the breathing cycle. The results demonstrate the accuracy of the investigations, enabling detailed analysis of flow structures and gradients. This spatial high-resolution tomo-PIV approach provides valuable insights into the complex flow phenomena occurring during the physiological breathing cycle in the nasopharynx. The study's findings contribute to advancements in non-free-of-sight experimental flow investigation of complex cavities under nearly realistic conditions. Furthermore, reliable and accurate experimental data is crucial for properly validating numerical approaches that compute this patient-specific flow for clinical purposes.}, language = {en} } @article{RomanoEhrlich, author = {Romano, Marco and Ehrlich, Ingo}, title = {Classification of damping properties of fabric-reinforced flat beam-like specimens by a degree of ondulation implying a mesomechanic kinematic}, series = {Science and Engineering of Composite Materials}, volume = {31}, journal = {Science and Engineering of Composite Materials}, number = {1}, publisher = {Walter de Gruyter GmbH}, issn = {2191-0359}, doi = {10.1515/secm-2024-0019}, abstract = {In order to determine the influence of the ondulations in fabrics on the damping properties of fiber-reinforced plastics, the structural dynamic properties of fabric- and unidirectionally reinforced plastics are investigated. The free decay behavior of flat beam-like specimens is investigated under fixed-free boundary conditions. As the material damping is consistently higher in fabric-reinforced specimens compared to unidirectionally reinforced ones, a contribution of an additionally acting mesomechanic kinematic in fabric weaves is implied. Based on a degree of ondulation, it is possible to classify the enhancement of the material damping and determine the corresponding energy dissipation. The study provides valuable quantitative relations of the additional damping effect due to the mesomechanic kinematic. Compared to the unidirectionally reinforced material, plain weave enhances the material damping by 37…52\% at ˜OPL=0.0133 , whereas twill weave 2/2 enhances it by 31…40\% at ˜OT2=0.0098 . The consideration of the findings contributes to a deeper understanding of the visco-elastic dynamic behavior of fabric-reinforced plastics and allows further applications in research, development, and industry.}, language = {en} } @article{KloiberSchultheissSoteloetal., author = {Kloiber, Jessica and Schultheiß, Ulrich and Sotelo, Lamborghini and Sarau, George and Christiansen, Silke H. and Gavras, Sarkis and Hort, Norbert and Hornberger, Helga}, title = {Corrosion behaviour of electropolished magnesium materials}, series = {Materials Today Communications}, journal = {Materials Today Communications}, edition = {Journal Pre-proof}, publisher = {Elsevier}, doi = {10.1016/j.mtcomm.2023.107983}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-68254}, abstract = {Although magnesium and its alloys are promising candidates as biodegradable implant materials, the tendency for localized corrosion mechanism in physiological environment limit their biomedical application. Electropolishing is an attractive strategy for improving the corrosion behaviour of metals, but it is still largely unexplored in magnesium materials. In this study, the characterization of electropolished surfaces of AM50 and pure magnesium was performed, focussing on their in vitro degradation behaviour in cell medium. Corrosion rates were evaluated using potentiodynamic polarisation. The surface morphology before and after the onset of corrosion was investigated by scanning electron microscopy and confocal laser scanning microscopy. The presented electropolishing process led to improved surface performances, observable by significantly lower corrosion rates (0.08 mm·year-1 in Dulbecco's modified Eagle's medium), lower arithmetical mean height (0.05 µm), lower water contact angle (25-35°) and lower micro hardness (35-50 HV 0.1) compared to mechanically and chemically treated surfaces. MgO/Mg(OH)2 could be detected on electropolished surfaces. The localized corrosion mode could be reduced, but not entirely prevented. Electropolishing shows great potential as post-treatment of magnesium-based components, but detailed tests of the long-term corrosion behaviour are an important area of future research.}, language = {en} } @article{FoerstlSuessEnglertetal., author = {F{\"o}rstl, Nikolas and S{\"u}ß, Franz and Englert, Carsten and Dendorfer, Sebastian}, title = {Design of a reverse shoulder implant to measure shoulder stiffness during implant component positioning}, series = {Medical Engineering \& Physics}, volume = {121}, journal = {Medical Engineering \& Physics}, edition = {Journal Pre-proof}, publisher = {Elsevier}, doi = {10.1016/j.medengphy.2023.104059}, pages = {22}, abstract = {To avoid dislocation of the shoulder joint after reverse total shoulder arthroplasty, it is important to achieve sufficient shoulder stability when placing the implant components during surgery. One parameter for assessing shoulder stability can be shoulder stiffness. The aim of this research was to develop a temporary reverse shoulder implant prototype that would allow intraoperative measurement of shoulder stiffness while varying the position of the implant components. Joint angle and torque measurement techniques were developed to determine shoulder stiffness. Hall sensors were used to measure the joint angles by converting the magnetic flux densities into angles. The accuracy of the joint angle measurements was tested using a test bench. Torques were determined by using thin-film pressure sensors. Various mechanical mechanisms for variable positioning of the implant components were integrated into the prototype. The results of the joint angle measurements showed measurement errors of less than 5° in a deflection range of ±15° adduction/abduction combined with ±45° flexion/extension. The proposed design provides a first approach for intra-operative assessment of shoulder stiffness. The findings can be used as a technological basis for further developments.}, language = {en} } @article{BartschBurgerGradetal., author = {Bartsch, Alexander and Burger, Moritz and Grad, Marius and Esper, Lukas and Schultheiß, Ulrich and Noster, Ulf and Schratzenstaller, Thomas}, title = {Enhancement of laser cut edge quality of ultra-thin titanium grade 2 sheets by applying an in-process approach using modulated Yb:YAG continuous wave fiber laser}, series = {Discover Mechanical Engineering}, journal = {Discover Mechanical Engineering}, number = {10}, publisher = {Springer}, doi = {10.1007/s44245-023-00018-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65647}, pages = {9}, abstract = {Titanium is used in many areas due to its excellent mechanical, biological and corrosion-resistant properties. Implants often have thin and filigree structures, providing an ideal application for fine cutting with laser. In the literature, the main focus is primarily on investigating and optimizing the parameters for titanium sheets with thicknesses greater than 1 mm. Hence, in this study, the basic manufacturing parameters of laser power, cutting speed and laser pulse of a 200 W modulated fiber laser are investigated for 0.15 mm thick grade 2 titanium sheets. A reproducible, continuous cut could be achieved using 90 W laser-power and 2 mm/s cutting-speed. Pulse pause variations between 85 and 335 μs in 50 μs steps and a fixed pulse width of 50 μs show that a minimum kerf width of 23.4 μm, as well as a minimum cut edge roughness Rz of 3.59 μm, is achieved at the lowest pulse pause duration. An increase in roughness towards the laser exit side, independent of the laser pulse pause duration, was found and discussed. The results provide initial process parameters for cutting thin titanium sheets and thus provide the basis for further investigations, such as the influence of cutting gas pressure and composition on the cut edge.}, language = {en} } @article{KaessStrahringerWestner, author = {K{\"a}ss, Sebastian and Strahringer, Susanne and Westner, Markus}, title = {A Multiple Mini Case Study on the Adoption of Low Code Development Platforms in Work Systems}, series = {IEEE Access}, journal = {IEEE Access}, publisher = {IEEE}, issn = {2169-3536}, doi = {10.1109/ACCESS.2023.3325092}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65634}, pages = {118762 -- 118786}, abstract = {Although adopting Low Code Development Platforms (LCDPs) promises significant efficiency and effectiveness improvements for application development, its adoption still needs further empirical research. This paper uses a combinatorial approach to research LCDP adoption and presents the results of a multiple mini case study with 36 cases on LCDP adoption. A combination of the Socio-Technical Systems theory and the Technology-Organisational-Environment model is used as a theoretical lens. In this paper, we show that LCDP adoption is a multifaceted phenomenon and identify three archetypes for LCDP adoption (i.e., IT Resource Shortage Mitigators, Application Development Democratisers, and Synergy Realisers) and one archetype for LCDP non-adoption (i.e., Intricacy Adversaries). Each archetype can be interpreted as an individual path towards LCDP (non-)adoption. Based on these archetypes, we derive seven starting points for practitioners to adopt LCDPs in work systems. Moreover, by using the theoretical lenses, the paper shows that for an LCDP adoption to occur, an optimisation of the social and technical sub-systems is required.}, language = {en} } @article{MikhaeilNowakPalombaetal., author = {Mikhaeil, Makram and Nowak, Sebastian and Palomba, Valeria and Frazzica, Andrea and Gaderer, Matthias and Dawoud, Belal}, title = {Experimental and analytical investigation of applying an asymmetric plate heat exchanger as an evaporator in a thermally driven adsorption appliance}, series = {Applied Thermal Engineering}, journal = {Applied Thermal Engineering}, number = {228}, publisher = {Elsevier}, doi = {10.1016/j.applthermaleng.2023.120525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-61115}, abstract = {This communication presents an experimental and analytical study on the evaporation mechanism in a closed-structured asymmetric plate heat exchanger (PHE) employed as a stagnant water evaporator for the application in an adsorption heat transformation appliance. To this aim, an experimental unit is constructed, which comprises two identical PHEs, one acting as an vaporator/condenser and the second, as an adsorber/desorber. Two endoscopes are mounted inside the investigated evaporator to visualize the evaporation mechanism when performing adsorption-evaporation processes under different boundary conditions. It turned out that the evaporation mechanism is a partially covered, thin film evaporation. A heat transfer analysis is performed to evaluate the heat transfer coefficient of the thin film evaporation () inside the investigated evaporator, resulting in -values between 1330 and 160 [W∙m-2∙K-1] over the investigated adsorption-evaporation time. Correlating the obtained () to the film thickness and the wetted area results in -values between 0.34 and 0.78 [mm] and wetted to total area ratios of 0.78 to 0.16. Besides, an analytical model has been developed and introduced to correlate the overall evaporator heat transfer coefficient with the adsorption potential and the time rate of change of the water uptake.}, language = {en} } @article{FrankeWagnerKrause, author = {Franke, Markus and Wagner, Marcus and Krause, Tom Janis}, title = {Data-driven model order reduction with surrogate elements for transient simulations}, series = {Engineering Computations : International journal for computer-aided engineering and software}, volume = {2025}, journal = {Engineering Computations : International journal for computer-aided engineering and software}, publisher = {Emerald Publishing}, address = {Leeds}, doi = {10.1108/EC-06-2024-0511}, pages = {26}, abstract = {Purpose - The purpose of this study is to introduce surrogate elements for static and transient finite element simulations. These elements are designed to replace regions of several conventional solid elements with a single artificial element that possesses a reduced number of degrees of freedoms (dofs). A notable advantage of our surrogate elements is their seamless integration into standard finite element meshes. Design/methodology/approach - The construction of the surrogate elements stiffness and mass matrices is achieved through an optimization process wherein displacements serve as the optimization objective. Moreover, the matrices are designed to possess properties analogous to those of standard finite elements. A particular focus is placed on ensuring that the artificial stiffness matrices are positive semi-definite. Furthermore, artificial degrees of freedom are introduced. Findings - The efficacy of the proposed technique is demonstrated through its application to two different use cases. It is demonstrated that, despite being trained on examples comprising a single surrogate element, the surrogate elements can be employed multiple times within complex and practical models. The degree of accuracy achieved in these applications is noteworthy. Moreover, the proposed method is considerably faster than the fully discretized models. Originality/value - The study expands the field of substructuring and model order reduction by incorporating artificial surrogate elements built by neural networks, which enables seamless integration with standard finite element analysis via positive semi-definite matrices. Furthermore, the introduction of artificial degrees of freedom, which are detached from the computational domain, is proposed. Once trained, the surrogate elements can be utilised in load and support independent scenarios.}, language = {en} } @article{SchuheggerKaraGalkaetal., author = {Schuhegger, Lukas and Kara, Sinan and Galka, Stefan and D{\"u}nnweber, Jan and Meißner, Sebastian}, title = {Umzugsplanung mit Fabrikdatenmodellen und Virtual Reality}, series = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, volume = {119}, journal = {Zeitschrift f{\"u}r wirtschaftlichen Fabrikbetrieb}, number = {11}, publisher = {de Gruyter}, issn = {2511-0896}, doi = {10.1515/zwf-2024-1154}, pages = {799 -- 804}, abstract = {Angesichts eines dynamischen industriellen Umfelds m{\"u}ssen produzierende Unternehmen flexibel bleiben und sich kontinuierlich anpassen, um ihre Wettbewerbsf{\"a}higkeit zu erhalten. Eine effektive Planung von Restrukturierungen in Produktionssystemen, oft als Umzugsplanung bezeichnet, ist entscheidend, um Verz{\"o}gerungen zu vermeiden und Stillstandszeiten zu minimieren. Die Identifikation von Umzugsf{\"a}llen, welche den Umfang umzuziehender Ressourcen wie Maschinen, Anlagen, Ausr{\"u}stungen und Arbeitspl{\"a}tzen beschreiben und die Definition zugeh{\"o}riger Aufgaben sind essenzielle Schritte der Umzugsplanung. Dieser Beitrag stellt eine Vorgehensweise zur Bestimmung von Umzugsf{\"a}llen mittels eines Fabrikdatenmodells vor, erg{\"a}nzt durch eine Visualisierung in Virtual Reality, um Planende bei der Umzugsplanung zu unterst{\"u}tzen.}, language = {de} } @article{SchmidbauerBeckerHaug, author = {Schmidbauer, Simon and Becker, Maria and Haug, Sonja}, title = {Online Political Participation of Refugees in Germany: Analysis of a Survey in Bavaria}, series = {Sage Online}, journal = {Sage Online}, publisher = {Sage}, address = {Thousand Oaks}, doi = {10.1177/21582440241286303}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-77671}, abstract = {New media are an important resource for the political participation of marginalized groups. However, there is still a lack of knowledge about the factors that influence whether this opportunity is used. Influencing factors emerge from both the Civic Voluntarism Model and previous research on migrants' political activity. Using data collected in 2019/2020 from 486 refugees living in Bavaria, we estimate linear probability models to investigate facilitating factors for the use of new media for political participation. The analysis shows that refugees in Germany who inform themselves about politics online tend to be predominantly male, higher educated, and politically involved. Language skills and the duration of stay also appear to be important. For the expression of one's political opinion online, gender and language skills have an impact, but informing oneself about German politics, political interest, and offline political activity in Germany are the most relevant factors. This indicates that there is a close link between on- und offline activity. However, using the internet requires particular resources, so that people with lower language skills, for example, are particularly disadvantaged.}, language = {de} } @article{GradSchultheissDiemaretal., author = {Grad, Marius and Schultheiß, Ulrich and Diemar, Andreas and Spieß, Lothar and Noster, Ulf}, title = {Preparation methodology for the microstructural characterization of diffusion layers in a titanium/steel composite}, series = {Practical Metallography}, volume = {61}, journal = {Practical Metallography}, number = {12}, publisher = {Walter de Gruyter GmbH}, issn = {2195-8599}, doi = {10.1515/pm-2024-0087}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-78346}, pages = {938 -- 946}, abstract = {Hot pressing of titanium and carbon steel leads to the formation of a diffusion layer at the interface. Depending on the carbon content of the steel used, it either exclusively contains TiC or additional other phases. In the case of steel with a medium carbon concentration (0.67 wt.\% C), a pure TiC layer forms. A preparation methodology was developed to make statements about functional and microstructural properties of the respective layers such as layer thickness, porosity, or grain size. However, apart from the diffusion layer's microstructure, it also reveals the microstructure of the two base substrates. A comparison based on electron backscatter diffraction (EBSD) examinations yields similar results in terms of microstructure. A micrograph analysis based on the new preparation methodology also allows confirming the element distribution measurement by glow discharge optical emission spectroscopy (GDOES). The methodology therefore provides a way of quickly and reliably controlling the layer formation during the hot pressing process of titanium and carbon steel.}, language = {en} } @article{RauchBrueckl, author = {Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Achieving Optimal Reactive Power Compensation in Distribution Grids by Using Industrial Compensation Systems}, series = {Electricity}, volume = {4}, journal = {Electricity}, number = {1}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/electricity4010006}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59139}, pages = {78 -- 95}, abstract = {This paper presents a method for integrating industrial consumers owning compensation systems as alternative reactive power sources into grid operating processes. In remuneration, they receive a market-based provision of reactive power. The aim is to analyze the potential of reactive power compensation systems of industrial companies connected to medium-voltage (10 kV-30 kV) AC grids in order to increase the reactive power ability of distribution grids. Measurement methods and reactive power potential results of six industrial companies are presented to characterize the amount and temporal availability of their reactive power potential. The presented approach for using the decentralized reactive power potential is a centralized reactive power control method and is based on optimal power flow (OPF) calculations. An optimization algorithm based on linear programming is used to coordinate a reactive power retrieval tuned to the actual demand. The influencing quantities are the current grid status (voltage and load flow capacity reserves at grid nodes and power lines) and the current reactive power potential of the reactive power sources. The compensation impact of six measured industrial companies on an exemplary medium-voltage grid is shown by an application example.}, language = {en} } @article{RoehrlStauferBugertetal., author = {R{\"o}hrl, Simon and Staufer, Susanne and Bugert, Flemming and Nadimpalli, Vamsi Krishna and Hauser, Florian and Grabinger, Lisa and Bittner, Dominik and Ezer, Timur and Altweck, Ricardo and Graf, Sabine and Kriza, Thomas and Mottok, J{\"u}rgen}, title = {Ethical Considerations of AI in Education: A Case Study based on Pythia Learning Enhancement System}, series = {IEEE Access}, volume = {11}, journal = {IEEE Access}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2169-3536}, doi = {10.1109/ACCESS.2025.3583975}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-83403}, pages = {1 -- 25}, abstract = {As the use of AI in education increases, addressing ethical concerns is essential for its responsible use and implementation. This study explores the ethical considerations of AI in education by analyzing a concrete application, the Pythia Learning Enhancement System, which enables personalized and adaptive educational experiences. In this case study, the concrete implementation of Pythia, contrary to high-level abstract analyses, provides practical insights into these ethical issues. To achieve this goal, we first define Pythia and outline its implementation. Using the various topics covered by Pythia, the ethical issues associated with each of these topics are outlined, resulting in a list of ten distinct ethical issues. Because there is overlap in issues covered by similar applications, they can benefit from this identification. An ethical (human rights) and didactic (constructivism) theoretical background is then provided as a basis for further discussion. This is used to build the arguments used in the main study. This consists of analyzing each of the issues and providing recommendations to mitigate potential harm arising from these issues. This helps to provide guidelines for future applications. In the analysis, the ethical discussion is mainly based on the human rights of the stakeholders involved, emphasizing human dignity. After the analysis, each of the issues is contextualized with the recent AI Act of the European Union, providing a novel mapping of the issues of AI in education to the AI Act. Finally, the limitations of the study are stated and a plan for future research is presented.}, language = {en} } @article{KnoedlerDeanKnoedleretal., author = {Kn{\"o}dler, Leonard and Dean, Jillian and Knoedler, Samuel and Kauke-Navarro, Martin and Hollmann, Katharina and Alfertshofer, Michael and Helm, Sabrina and Prantl, Lukas and Schliermann, Rainer}, title = {Hard shell, soft core? Multi-disciplinary and multi-national insights into mental toughness among surgeons}, series = {Frontiers in Surgery}, volume = {11}, journal = {Frontiers in Surgery}, publisher = {Frontiers}, doi = {10.3389/fsurg.2024.1361406}, pages = {7}, abstract = {Background: With the prevalence of burnout among surgeons posing a significant threat to healthcare outcomes, the mental toughness of medical professionals has come to the fore. Mental toughness is pivotal for surgical performance and patient safety, yet research into its dynamics within a global and multi-specialty context remains scarce. This study aims to elucidate the factors contributing to mental toughness among surgeons and to understand how it correlates with surgical outcomes and personal well-being. Methods: Utilizing a cross-sectional design, this study surveyed 104 surgeons from English and German-speaking countries using the Mental Toughness Questionnaire (MTQ-18) along with additional queries about their surgical practice and general life satisfaction. Descriptive and inferential statistical analyses were applied to investigate the variations in mental toughness across different surgical domains and its correlation with professional and personal factors. Results: The study found a statistically significant higher level of mental toughness in micro-surgeons compared to macro-surgeons and a positive correlation between mental toughness and surgeons' intent to continue their careers. A strong association was also observed between general life satisfaction and mental toughness. No significant correlations were found between the application of psychological skills and mental toughness. Conclusion: Mental toughness varies significantly among surgeons from different specialties and is influenced by professional dedication and personal life satisfaction. These findings suggest the need for targeted interventions to foster mental toughness in the surgical community, potentially enhancing surgical performance and reducing burnout. Future research should continue to explore these correlations, with an emphasis on longitudinal data and the development of resilience-building programs.}, language = {en} } @article{GebhardtSchlampEhrlichetal., author = {Gebhardt, Jakob and Schlamp, Matthias and Ehrlich, Ingo and Hiermaier, Stefan}, title = {Low-velocity impact behavior of elliptic curved composite structures}, series = {International Journal of Impact Engineering}, volume = {180}, journal = {International Journal of Impact Engineering}, publisher = {Elsevier}, doi = {10.1016/j.ijimpeng.2023.104663}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59304}, pages = {8}, abstract = {Although many composite structures are inconsistently curved, such as the leading edges of aircraft wings, the variety of research in impact engineering is almost limited to the impact performance of plates or cylindrically curved specimens. It is not known whether the findings obtained from standardized tests can be transferred to curved structures or which adaptions are required. Therefore, a deeper understanding of the deformation and damage behavior of inconsistently curved structures is essential to transfer the observed impact behavior of flat specimens to general curved structures and therefore to utilize the full lightweight potential of a load-specific design. An accurate description of the procedure as well as the results of the experimental and numerical study of the low-velocity impact behavior of differently single-curved elliptic specimens is presented. To close the research gap of the impact behavior of geometries with curvatures between the plates and simplified leading edges, novel specimens geometries have been derived from established impact test standards. Glassfiber-reinforced specimens are subjected to an instrumented impact test at constant impact energy. This is numerically investigated by a stacked-layer model, which used cohesive zone modeling to enable the simulation of matrix cracking, fiber fracture and delamination. The resulting projected damage areas, as well as the force and deflection histories, were evaluated and section cuts were examined to discuss the damage morphology, formation and propagation process. Significant effects on maximum deflection, compliance and dynamic behavior on the size and morphology of damage were found.}, language = {en} } @article{MarkovGlazerElbeSchliermann, author = {Markov-Glazer, Alon and Elbe, Anne-Marie and Schliermann, Rainer}, title = {From their eyes: Deaflympic athletes' and coaches' perspectives on mental training}, series = {Frontiers in sports and active living}, volume = {7}, journal = {Frontiers in sports and active living}, publisher = {Frontiers}, doi = {10.3389/fspor.2025.1613833}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-84183}, pages = {15}, abstract = {INTRODUCTION Sport psychology research has largely overlooked athletes with hearing impairments competing in Deaflympic sports, the designated elite sporting movement for this population. This study therefore explored Deaflympic athletes' and coaches' perspectives on mental training in the elite Deaf sports. METHODS A qualitative approach was used, involving six focus group interviews with 23 athletes (Mage = 33.09; 26.1\% female) and four coaches from individual and team Deaf sports. Data were analyzed using reflexive thematic analysis. RESULTS Three themes emerged: sport psychology consultation, the influence of visual orientation on psychological skills and demands, and Deaf sport culture and communication. While participants expressed strong interest in sport psychology, engagement with professionals was limited by accessibility issues, lack of sign language-fluent consultants, and structural barriers. Deaf athletes reported adapting some techniques to match their visual-spatial orientation and both advantages and challenges of visual reliance in sports. Distinct communication dynamics between native signers and spoken-language users within Deaf teams were also revealed. DISCUSSION These findings highlight the importance of culturally sensitive sport psychology frameworks that support the needs and preferences of Deaflympic athletes and promote equitable access to effective mental training resources.}, language = {en} } @article{MendelRauberSouzaJretal., author = {Mendel, Robert and Rauber, David and Souza Jr., Luis Antonio de and Papa, Jo{\~a}o Paulo and Palm, Christoph}, title = {Error-Correcting Mean-Teacher: Corrections instead of consistency-targets applied to semi-supervised medical image segmentation}, series = {Computers in Biology and Medicine}, volume = {154}, journal = {Computers in Biology and Medicine}, number = {March}, publisher = {Elsevier}, issn = {0010-4825}, doi = {10.1016/j.compbiomed.2023.106585}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-57790}, pages = {13}, abstract = {Semantic segmentation is an essential task in medical imaging research. Many powerful deep-learning-based approaches can be employed for this problem, but they are dependent on the availability of an expansive labeled dataset. In this work, we augment such supervised segmentation models to be suitable for learning from unlabeled data. Our semi-supervised approach, termed Error-Correcting Mean-Teacher, uses an exponential moving average model like the original Mean Teacher but introduces our new paradigm of error correction. The original segmentation network is augmented to handle this secondary correction task. Both tasks build upon the core feature extraction layers of the model. For the correction task, features detected in the input image are fused with features detected in the predicted segmentation and further processed with task-specific decoder layers. The combination of image and segmentation features allows the model to correct present mistakes in the given input pair. The correction task is trained jointly on the labeled data. On unlabeled data, the exponential moving average of the original network corrects the student's prediction. The combined outputs of the students' prediction with the teachers' correction form the basis for the semi-supervised update. We evaluate our method with the 2017 and 2018 Robotic Scene Segmentation data, the ISIC 2017 and the BraTS 2020 Challenges, a proprietary Endoscopic Submucosal Dissection dataset, Cityscapes, and Pascal VOC 2012. Additionally, we analyze the impact of the individual components and examine the behavior when the amount of labeled data varies, with experiments performed on two distinct segmentation architectures. Our method shows improvements in terms of the mean Intersection over Union over the supervised baseline and competing methods. Code is available at https://github.com/CloneRob/ECMT.}, language = {en} } @article{DiachkovaNikolaevaGuertler, author = {Diachkova, Yana and Nikolaeva, Sofiya and Guertler, Katherine}, title = {Communication in International Humanitarian Relief: Profiling Ukrainian Boundary Spanners}, series = {Journal of Intercultural Communication}, volume = {25}, journal = {Journal of Intercultural Communication}, number = {1}, publisher = {ICR Publications}, issn = {1404-1634}, doi = {10.36923/jicc.v25i1.1019}, pages = {98 -- 106}, abstract = {Boundary spanning—the actions and roles individuals or organizations undertake to bridge differences and facilitate communication, collaboration, and understanding across diverse cultural, organizational, or geographical divisions—is an essential element of international cooperation. Set against the backdrop of the Russia-Ukraine war, The purpose of this study is to explore the type of boundary spanning in this uncertain context, the linguistic characteristics of boundary spanners, the necessary skills and competencies required to navigate the complex socio-political landscape, and the role of boundary spanners in humanitarian assistance. This study employs a qualitative research approach, using semi-structured interviews with informants actively engaged in relief efforts and cross-cultural collaboration. The findings emphasized the significance of English as the primary language of communication, the importance of cultural sensitivity and awareness, and the need for intercultural competence in effective boundary spanning. The study concludes with insights from the ongoing Ukrainian experience of bridging geodemographic boundaries and the role of boundary spanners in this process, highlighting key aspects of boundary spanning. Overall, the study contributes to the theoretical background of boundary spanning and enhances the understanding of how linguistic and cultural boundary spanning can drive positive change and improve outcomes in humanitarian aid. The implications of this study suggest that underscore the critical need for collaboration with experienced boundary spanners in educational settings.}, language = {en} } @article{SchmidThiel, author = {Schmid, Michael T. and Thiel, Charlotte}, title = {Is it worth it? Potential for reducing the environmental impact of bitumen roofing membrane production}, series = {Recycling}, volume = {10}, journal = {Recycling}, number = {6}, publisher = {MDPI}, doi = {10.3390/recycling10060208}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-86873}, pages = {24}, abstract = {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.}, language = {en} } @article{SchummBrownAbdelKhaleketal., author = {Schumm, Leon and Brown, Tom and Abdel-Khalek, Hazem and Ueckerdt, Falko and Sterner, Michael and Fioriti, David and Parzen, Max}, title = {The impact of temporal hydrogen regulation on hydrogen exporters and their domestic energy transition}, series = {Nature Communications}, volume = {16}, journal = {Nature Communications}, publisher = {Nature}, address = {London}, doi = {10.1038/s41467-025-62873-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-84857}, pages = {13}, abstract = {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.}, language = {en} } @article{SchmiedtEmpacherKamps, author = {Schmiedt, Anja B. and Empacher, Christina and Kamps, Udo}, title = {One- and two-sided prediction intervals for future Pareto record values with applications}, series = {Journal of Statistical Theory and Applications}, journal = {Journal of Statistical Theory and Applications}, publisher = {Springer}, issn = {2214-1766}, doi = {10.1007/s44199-025-00119-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-81605}, pages = {26}, abstract = {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.}, language = {en} } @article{DotterHaugSchnelletal., author = {Dotter, Caroline and Haug, Sonja and Schnell, Rainer and Raptis, Georgios and Weber, Karsten}, title = {Sharing health data for research purposes: results of a population survey in Germany}, series = {BMC health services research}, volume = {25}, journal = {BMC health services research}, publisher = {BMC}, doi = {10.1186/s12913-025-12706-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-81622}, pages = {9}, abstract = {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.}, language = {en} } @inproceedings{FranzWinkerGroppeetal., author = {Franz, Maja and Winker, Tobias and Groppe, Sven and Mauerer, Wolfgang}, title = {Hype or Heuristic? Quantum Reinforcement Learning for Join Order Optimisation}, series = {2024 IEEE International Conference on Quantum Computing and Engineering (QCE), 15-20 September 2024, Montreal, QC, Canada}, booktitle = {2024 IEEE International Conference on Quantum Computing and Engineering (QCE), 15-20 September 2024, Montreal, QC, Canada}, publisher = {IEEE}, doi = {10.1109/QCE60285.2024.00055}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-76877}, pages = {409 -- 420}, abstract = {Identifying optimal join orders (JOs) stands out as a key challenge in database research and engineering. Owing to the large search space, established classical methods rely on approximations and heuristics. Recent efforts have successfully explored reinforcement learning (RL) for JO. Likewise, quantum versions of RL have received considerable scientific attention. Yet, it is an open question if they can achieve sustainable, overall practical advantages with improved quantum processors. In this paper, we present a novel approach that uses quantum reinforcement learning (QRL) for JO based on a hybrid variational quantum ansatz. It is able to handle general bushy join trees instead of resorting to simpler left-deep variants as compared to approaches based on quantum(-inspired) optimisation, yet requires multiple orders of magnitudes fewer qubits, which is a scarce resource even for post-NISQ systems. Despite moderate circuit depth, the ansatz exceeds current NISQ capabilities, which requires an evaluation by numerical simulations. While QRL may not significantly outperform classical approaches in solving the JO problem with respect to result quality (albeit we see parity), we find a drastic reduction in required trainable parameters. This benefits practically relevant aspects ranging from shorter training times compared to classical RL, less involved classical optimisation passes, or better use of available training data, and fits data-stream and low-latency processing scenarios. Our comprehensive evaluation and careful discussion delivers a balanced perspective on possible practical quantum advantage, provides insights for future systemic approaches, and allows for quantitatively assessing trade-offs of quantum approaches for one of the most crucial problems of database management systems.}, language = {en} } @article{QiaoGradNonn, author = {Qiao, Yu and Grad, Marius and Nonn, Aida}, title = {Toward an Efficient and Robust Process-Structure Prediction Framework for Filigree L-PBF 316L Stainless Steel Structures}, series = {Metals}, volume = {15}, journal = {Metals}, number = {7}, publisher = {MDPI}, issn = {2075-4701}, doi = {10.3390/met15070812}, pages = {22}, abstract = {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.}, language = {en} }