TY - JOUR A1 - Gärtner, Sebastian A1 - Marx-Schubach, Thomas A1 - Gaderer, Matthias A1 - Schmitz, Gerhard A1 - Sterner, Michael T1 - Techno-Economic Analysis of Carbon Dioxide Separation for an Innovative Energy Concept towards Low-Emission Glass Melting JF - energies N2 - 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. KW - economic evaluation KW - CO2-separation KW - glass industry KW - oxyfuel KW - methanation KW - power-to-gas Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-53627 N1 - Corresponding author: Sebastian Gärtner VL - 16 IS - 5 SP - 1 EP - 25 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zacherl, Florian A1 - Wopper, Christoph A1 - Schwanzer, Peter A1 - Rabl, Hans-Peter T1 - Potential of the Synthetic Fuel Oxymethylene Ether (OME) for the Usage in a Single-Cylinder Non-Road Diesel Engine: Thermodynamics and Emissions JF - Energies N2 - 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. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-55350 N1 - Project: NAMOSYN: Nachhaltige Mobilität durch synthetische Kraftstoffe (Funding Nr. 03SF0566N0) N1 - Corresponding author: Florian Zacherl VL - 15 IS - 21 SP - 1 EP - 26 PB - MDPI ER - TY - JOUR A1 - Troidl, Kilian A1 - Schroll-Decker, Irmgard T1 - Wie theoriebasiert sind Forschungsbeiträge zur Bildungsbeteiligung? Eine Qualitative Inhaltsanalyse ausgewählter Fachzeitschriften der Erwachsenen- und Weiterbildungsforschung JF - Zeitschrift für Weiterbildungsforschung N2 - 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 Prüfung eine theoretische Weiterentwicklung des Forschungsfeldes erschwere. Mittels einer Qualitativen Inhaltsanalyse von Beiträgen ausgewählter Fachzeitschriften der Erwachsenen‑/Weiterbildungsforschung wurde versucht, die Aktualität dieser Feststellung empirisch zu überprüfen. Dazu wurden 38 empirische Forschungsbeiträge zur Bildungsbeteiligung der Jahrgänge 2018 bis 2020 von neun Fachzeitschriften mit Peer-Review untersucht. Die Einschätzung der Beiträge erfolgte hinsichtlich des Grades der Theorieeinbindung. Die Ergebnisse der Analyse zeigen ein gemischtes Bild: neun Beiträge (24 %) binden keine Theorie in den Forschungsprozess ein, ein Beitrag (3 %) zitiert Theorie lediglich, ohne sie weiter einzubinden. Am häufigsten ist eine Einbindung zum theoriegeleiteten Vorgehen (16 Beiträge, 42 %). Eine tiefergehende Theorieanwendung findet sich in sechs Beiträgen (16 %). Eine theorieprüfende oder -bildende Einbindung liegt mit je drei Beiträgen (je 8 %) seltener vor. Die rezipierten Theorien sind vielfältig: es werden 20 verschiedene Theorieansätze festgestellt. Den Forderungen nach einer verstärkten Einbindung von Theorie in den Forschungsprozess kann somit weiterhin Gültigkeit attestiert werden: ein substanzieller Teil der Beiträge berichtet keine Theorieeinbindung, eine empirische Prüfung oder Weiterentwicklung findet relativ selten statt. N2 - Regarding empirical research on participation in adult education, it has been criticized that only rarely has there been an integration of theoretical and empirical approaches and that empirical testing was lacking. This, it has been stated, was an impediment to further developing the research field. To empirically check if this is still the case, a qualitative content analysis of selected journals in the field of adult and continuing education was carried out. 38 peer-reviewed articles, published in professional journals between 2018 and 2020, which presented empirical research on participation in adult education were examined. The main goal of this study was to assess the extent to which theory is used in these articles along a continuum of theory use. The result of the analysis gave a mixed picture. Nine contributions (24%) show no reference to theory at all, one contribution (3%) merely cites theoretical work without making further use of it. Most frequently, theory is reported to inform the empirical research (16 contributions, 42%); six contributions (16%) further apply theory. Only three contributions (8%) report either theory testing or building. The theories used vary: 20 different theoretical approaches were observed. A thorough integration of theory into the research process still seems to be lacking: Most articles report no or only limited use of theory. Empirical testing or further development of theory only takes place in a small portion of the studies analyzed. T2 - The use of theory in research on participation in adult education: A qualitative content analysis of key adult and continuing education journals KW - Erwachsenenbildung KW - Weiterbildung KW - Wissenschaftliche Zeitschrift KW - Qualitative Inhaltsanalyse KW - Bildungsbeteiligung KW - Adult learning participation KW - Research on participation KW - Theory use KW - Journals KW - Qualitative content analysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-55460 N1 - Corresponding author: Irmgard Schroll-Decker VL - 45 PB - Springer Nature ER - TY - JOUR A1 - Schönberger, Manuel A1 - Scherzinger, Stefanie A1 - Mauerer, Wolfgang T1 - Ready to Leap (by Co-Design)? Join Order Optimisation on Quantum Hardware JF - Proceedings of the ACM on Management of Data, PACMMOD N2 - 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. KW - Hardware KW - Quantum cmputation KW - Informations systems KW - Join algorithms Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-56634 N1 - Corresponding author: Manuel Schönberger VL - 1 IS - 1 SP - 1 EP - 27 PB - ACM CY - New York, NY, ER - TY - JOUR A1 - Käss, Sebastian A1 - Strahringer, Susanne A1 - Westner, Markus T1 - Practitioners’ Perceptions on the Adoption of Low Code Development Platforms JF - IEEE Access N2 - 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. KW - Low code KW - Delphi Study KW - Software Development KW - Inhibitor KW - Driver Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-59170 SN - 2169-3536 N1 - Corresponding author: Markus Westner PB - IEEE ER - TY - JOUR A1 - Dotter, Caroline A1 - Haug, Sonja A1 - Weber, Karsten A1 - Schnell, Rainer A1 - Scharf, Anna A1 - Altenburcher, Amelie T1 - Analyzing factors determining vaccination willingness against COVID-19 in Germany 2020 JF - Vaccine: X N2 - 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. KW - COVID-19 KW - Willingness to be vaccinated KW - Predictors of vaccination KW - Complementary alternative medicine KW - Educational level Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-62900 VL - 14 PB - Elsevier ER - TY - JOUR A1 - Pangerl, Jonas A1 - Sukul, Pritam A1 - Rück, Thomas A1 - Fuchs, Patricia A1 - Weigl, Stefan A1 - Miekisch, Wolfram A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone JF - Photoacoustics N2 - 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. KW - Photoacoustic spectroscopy KW - Real-time mass-spectrometry KW - Breath analysis KW - Acetone KW - UV-LED Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-71279 SN - 2213-5979 N1 - Corresponding author der OTH Regensburg: Jonas Pangerl VL - 38 PB - Elsevier ER - TY - JOUR A1 - Albrecht, Sophie Viktoria A1 - Hellerbrand, Stefan A1 - Weininger, Florian A1 - Thiel, Charlotte T1 - Strategies for Minimizing Environmental Impact in Construction: A Case Study of a Cementitious 3D Printed Lost Formwork for a Staircase JF - materials N2 - 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 KW - permanent formwork KW - selective cement activation (SCA) KW - 3D concrete printing (3DCP) KW - life cycle assessment (LCA) KW - additive manufacturing in construction (AMC) Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79236 N1 - Corresponding author der OTHR: Sophie Viktoria Albrecht VL - 18 PB - MDPI ER - TY - JOUR A1 - Westner, Markus A1 - Reicheneder, Matthias A1 - Matschi, Markus T1 - From Captive Centers to Global Integration BT - Organizational Models and Good Practices in Information Technology Nearshoring and Offshoring JF - Information Resources Management Journal N2 - 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. KW - Offshoring KW - Informationstechnik KW - Internationale Arbeitsteilung KW - Organisationsstruktur KW - IT-Nearshoring KW - IT-Offshoring KW - Global IT-Teams KW - Organizational Models KW - Distributed Work Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-80406 SN - 1533-7979 N1 - Corresponding author der OTH Regensburg: Markus Westner VL - 38 IS - 1 PB - IGI Global ER - TY - JOUR A1 - Hausler, Peter A1 - Holzner, Lukas A1 - Ehrnsperger, Matthias A1 - Bierl, Rudolf T1 - Evaluation of the creep strength of samples produced by fused deposition modeling JF - Open Engineering N2 - 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. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79760 N1 - Corresponding author der OTH Regensburg: Peter Hausler VL - 14 IS - 1 PB - de Gruyter ER - TY - JOUR A1 - Haug, Sonja A1 - Schnell, Rainer A1 - Raptis, Georgios A1 - Dotter, Caroline A1 - Weber, Karsten T1 - Wissen und Einstellung zur Speicherung und Nutzung von Gesundheitsdaten: Ergebnisse einer Bevölkerungsbefragung JF - Zeitschrift für Evidenz, Fortbildung und Qualität im Gesundheitswesen N2 - Hintergrund/Zielsetzung Der Beitrag befasst sich mit dem Wissenstand und der Einstellung der Bevölkerung. Betrachtet werden die Übermittlung und Verfügbarkeit von Gesundheitsdaten, Gesundheitsregister, die elektronische Patientenakte, Einwilligungsverfahren für die Übermittlung von Daten und der Zugriff auf Gesundheitsdaten zu Forschungszwecken. Methoden Die Studie basiert auf einer computergestützten Telefonbefragung (Dual-Frame) bei einer Zufallsstichprobe der Bevölkerung in Deutschland im Zeitraum 01.-27.06.2022 (n = 1.308). Ergebnisse Der Wissensstand zur Übermittlung von Gesundheitsdaten an Krankenkassen ist hoch, wohingegen das Vorhandensein zentraler Sterbe-, Impf- und Gesundheitsregister sowie der Zugriff auf Gesundheitsdaten durch behandelnde Ärztinnen und Ärzte überschätzt werden. Die Akzeptanz medizinischer Register ist sehr hoch. Die elektronische Patientenakte ist bei der Hälfte der Bevölkerung unbekannt, die Nutzungsbereitschaft ist eher gering ausgeprägt; bei der Übertragung von Daten wird eine Zustimmungsoption bevorzugt, und über achtzig Prozent würden die Daten der elektronischen Patientenakte zur Forschung freigeben. Drei Viertel würden ihre Gesundheitsdaten allgemein zur Forschung freigeben, insbesondere an Universitäten in Deutschland, wobei meist Anonymität Bedingung ist. Die Bereitschaft zur Datenfreigabe steigt mit der Höhe des Vertrauens in die Presse sowie in Universitäten und Hochschulen, und sie sinkt, wenn ein Datenleck als schwerwiegend erachtet wird. Diskussion und Schlussfolgerung In Deutschland besteht, wie in anderen europäischen Ländern, 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 für eine erfolgreiche Einführung einer elektronischen Patientenakte gilt. Vertrauen in die Forschung und staatliche Stellen, die Gesundheitsdaten verarbeiten, sind zentrale Faktoren. T2 - Knowledge and attitudes towards sharing of health data: Results of a population survey Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-67461 SN - 1865-9217 N1 - Corresponding author: Sonja Haug N1 - Fragebogen u.d.T.: "Projekt: Privacy und Willingness to share von Gesundheitsdaten (PWG)"; auf dem Publikationsserver unter https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/6057 abgelegt. N1 - Preprint unter: https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/6144 SP - 50 EP - 58 PB - Elsevier ER - TY - JOUR A1 - Scharf, Anna A1 - Haug, Sonja A1 - Ritthaler, Markus A1 - Raptis, Georgios T1 - Chancen und Herausforderungen der Digitalisierung bei der Rehabilitation – Ergebnisse einer Befragung von Rehabilitationseinrichtungen JF - Die Rehabilitation: Zeitschrift für Praxis und Forschung in der Rehabilitation N2 - 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 für Rehabilitationseinrichtungen. Methodik: Teilstandardisierte Online-Befragung bei Trägern von Rehabilitationseinrichtungen in Bayern (n=33). Der Fragebogen mit 36 Fragen beinhaltet eine leicht veränderte 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 Übermittlung patientenbezogener Daten (Eingang und Ausgang) erfolgt häufig analog, wohingegen die Verarbeitung innerhalb der Einrichtung in vielen Fällen bereits überwiegend 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 Änderung der gesetzlich-finanziellen Lage in Deutschland eröffnen sich für Rehabilitationseinrichtungen neue Möglichkeiten einer verstärkten Digitalisierung. Hürden hängen mit Anforderungen an IT-Sicherheit, Schulung des Personals und sowie dem ebenfalls geringen Digitalisierungsstand bei Krankenhäusern und Ärzt*innen sowie Patient*innen zusammen, die eine digitale Datenübermittlung erschweren. T2 - Opportunities and Challenges of Digitalization in Rehabilitation: Results of a Survey of Rehabilitation Facilities KW - Patientenbezogene Daten KW - Digitalisierungsgrad KW - Telematikinfrastruktur KW - IT-Management Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-64726 N1 - Corresponding author: Sonja Haug VL - 62 IS - 5 SP - 299 EP - 307 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Grad, Marius A1 - Zentgraf, Jan A1 - Schultheiss, Ulrich A1 - Esper, Lukas A1 - Diemar, Andreas A1 - Noster, Ulf A1 - Spiess, Lothar T1 - Effect of Carbon Content on the Phase Composition, Microstructure and Mechanical Properties of the TiC Layer Formed in Hot-Pressed Titanium-Steel Composites JF - Metals N2 - 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. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-74617 SN - 2075-4701 N1 - Cooresponding author der OTH Regensburg: Marius Grad VL - 14 IS - 9 PB - MDPI AG ER - TY - JOUR A1 - Auer, Simon A1 - Kubowitsch, Simone A1 - Dendorfer, Sebastian T1 - Kombinierter Einfluss von psychologischen und biomechanischen Faktoren auf die muskulären Belastungen beim Fußballspielen JF - Die Orthopädie N2 - 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. N2 - Für Fußballer:innen stellen muskuläre Verletzungen der unteren Extremitäten ein großes Problem dar. Ein Beispiel hierfür liefert die Nationalmannschaftsstürmerin Alexandra Popp, die aufgrund muskulärer Probleme das EM-Finale 2022 in Wembley kurzfristig verpasste. Oftmals stehen gerade hohe Anspannungssituationen in zeitlichem Zusammenhang mit Verletzungen, der Einfluss der psychischen Beanspruchung auf die biomechanischen Belastungen wird jedoch meist nur wenig beachtet. KW - Biologische Modelle KW - Biomechanik KW - Leistungssportler KW - Bewegung KW - Resilienz, psychologische KW - Biological models KW - Biomechanics KW - Elite athletes KW - Movement KW - Resilience, psychological Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-65113 N1 - Corresponding author: Sebastian Dendorfer VL - 52 IS - 11 SP - 1 EP - 6 PB - Springer ER - TY - JOUR A1 - Auer, Simon A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Using markerless motion capture and musculoskeletal models: An evaluation of joint kinematics JF - Technology and Health Care N2 - 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. KW - biomechanics KW - range of motion KW - musculoskeletal system KW - optical motion capture Y1 - 2024 U6 - https://doi.org/10.3233/THC-240202 SN - 0928-7329 N1 - Corresponding author der OTH Regensburg: Sebastian Dendorfer SP - 1 EP - 10 PB - IOS Press ER - TY - JOUR A1 - Köck, Hannah A1 - Striegl, Birgit A1 - Kraus, Annalena A1 - Zborilova, Magdalena A1 - Christiansen, Silke H. A1 - Schäfer, Nicole A1 - Grässel, Susanne A1 - Hornberger, Helga T1 - In Vitro Analysis of Human Cartilage Infiltrated by Hydrogels and Hydrogel-Encapsulated Chondrocytes JF - Bioengineering N2 - 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. KW - osteoarthritis KW - human articular cartilage KW - chondrocytes KW - hydrogels KW - zwitterionic monomers KW - infiltration Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-61235 N1 - Corresponding author: Helga Hornberger VL - 10 SP - 1 EP - 21 PB - MDPI ER - TY - JOUR A1 - Loo, Xuyan A1 - Nagaraju, Bhavana A1 - Pathivada, Sai A1 - Bartsch, Alexander A1 - Schratzenstaller, Thomas A1 - Sattler, Robert A1 - Monkman, Gareth J. T1 - Electrical properties of bisphenol-A-free magnetoactive borosilicate polymers JF - AIP Advances N2 - 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. KW - Electrical components KW - Electrical properties and parameters KW - Dielectric properties KW - Electrical resistivity KW - Magnetic materials KW - Viscoelasticity KW - Polymers KW - Non Newtonian fluids KW - Magnetic fluids Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-72936 SN - 2158-3226 N1 - Corresponding author der OTH Regensburg: Gareth J. Monkman VL - 14 IS - 5 PB - AIP Publishing ER - TY - JOUR A1 - Zentgraf, Jan A1 - Nützel, Florian A1 - Mühlbauer, Nico A1 - Schultheiss, Ulrich A1 - Grad, Marius A1 - Schratzenstaller, Thomas T1 - Surface Treatment of Additively Manufactured Polyetheretherketone (PEEK) by Centrifugal Disc Finishing Process: Identification of the Key Parameters JF - Polymers N2 - 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. KW - PEEK KW - fused deposition modeling KW - fused filament fabrication KW - centrifugal disc finishing KW - mass finishing KW - 3D printing KW - post-processing of 3D printed parts KW - surface treatment KW - high-performance polymers KW - additive manufacturing Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-73959 SN - 2073-4360 N1 - Corresponding author der OTH Regensburg: Jan Zentgraf VL - 16 PB - MDPI CY - Basel ER - TY - JOUR A1 - Tauwald, Sandra Melina A1 - Erzinger, Florian A1 - Quadrio, Maurizio A1 - Rütten, Markus A1 - Stemmer, Christian A1 - Krenkel, Lars T1 - Tomo-PIV in a patient-specific model of human nasal cavities: a methodological approach JF - Measurement Science and Technology N2 - 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. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-70393 N1 - Corresponding author: Sandra Melina Tauwald VL - 35 IS - 5 PB - IOP Publishing ER - TY - JOUR A1 - Romano, Marco A1 - Ehrlich, Ingo T1 - Classification of damping properties of fabric-reinforced flat beam-like specimens by a degree of ondulation implying a mesomechanic kinematic JF - Science and Engineering of Composite Materials N2 - 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. KW - fiber-reinforced plastics KW - mesomechanic scale KW - fabric-reinforced layer KW - ondulation Y1 - 2024 U6 - https://doi.org/10.1515/secm-2024-0019 SN - 2191-0359 SN - 0792-1233 N1 - Corresponding author der OTH Regensburg: Marco Romano VL - 31 IS - 1 PB - Walter de Gruyter GmbH ER -