TY - JOUR A1 - Pangerl, Jonas A1 - Müller, Max A1 - Rück, Thomas A1 - Weigl, Stefan A1 - Bierl, Rudolf T1 - Characterizing a sensitive compact mid-infrared photoacoustic sensor for methane, ethane and acetylene detection considering changing ambient parameters and bulk composition (N2, O2 and H2O) JF - Sensors and Actuators B: Chemical N2 - We present a sensitive and compact interband cascade laser (ICL) based photoacoustic setup for the detection of gaseous hydrocarbons and discuss its applicability towards trace gas analysis. We investigated the performance of the sensor for trace concentrations of methane, ethane and acetylene diluted in nitrogen. The excitation of methane and ethane was accomplished using one tunable diode laser, covering a range from 3360 to 3372 nm, which was replaced by a separate ICL at 3025 nm for acetylene detection. The influence of ambient parameters such as temperature, flow rate and pressure as well as potential cross-sensitivities towards O2 and H2O have been examined in terms of methane and acetylene detection. A series of simulations proved several of these influences to be attributed to relaxation effects. With a 3σ limit of detection (LoD) of 6.8 parts per billion (ppbV) in case of methane, 2.3 ppbV regarding ethane and 3.6 ppbV in terms of acetylene, the sensor demonstrates a great potential for applications in the field of trace gas analysis. KW - Acetylene KW - Cross-sensitivities KW - Ethane KW - Interband cascade laser KW - Methane KW - Photoacoustic spectroscopy KW - Relaxation effects Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-25868 N1 - Corresponding author: Jonas Pangerl VL - 352,1 SP - 1 EP - 12 PB - Elsevier ER - TY - JOUR A1 - Burdin, Dmitrii A. A1 - Ekonomov, Nikolai A. A1 - Chashin, Dmitri V. A1 - Fetisov, Leonid Y. A1 - Fetisov, Yuri K. A1 - Shamonin (Chamonine), Mikhail T1 - Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures JF - Materials N2 - The dependence of the resonant direct magnetoelectric effect on temperature is studied experimentally in planar composite structures. Samples of rectangular shapes with dimensions of 5 mm x 20 mm employed ferromagnetic layers of either an amorphous (metallic glass) alloy or nickel with a thickness of 20-200 m and piezoelectric layers of single crystalline langatate material or lead zirconate titanate piezoelectric ceramics with a thickness of 500 m. The temperature of the samples was varied in a range between 120 and 390 K by blowing a gaseous nitrogen stream around them. It is shown that the effective characteristics of the magnetoelectric effectsuch as the mechanical resonance frequency f(r), the quality factor Q and the magnitude of the magnetoelectric coefficient (E) at the resonance frequencyare contingent on temperature. The interrelations between the temperature changes of the characteristics of the magnetoelectric effect and the temperature variations of the following material parametersYoung's modulus Y, the acoustic quality factor of individual layers, the dielectric constant epsilon, the piezoelectric modulus d of the piezoelectric layer as well as the piezomagnetic coefficients ((n)) of the ferromagnetic layerare established. The effect of temperature on the characteristics of the nonlinear magnetoelectric effect is observed for the first time. The results can be useful for designing magnetoelectric heterostructures with specified temperature characteristics, in particular, for the development of thermally stabilized magnetoelectric devices. KW - acoustic quality factor KW - composite structure KW - linear KW - magnetoelectric effect KW - magnetoelectric heterostructure KW - magnetostriction KW - nonlinear KW - piezoelectric KW - temperature dependence Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-32185 N1 - corresponding author: Mikhail Shamonin VL - 10 IS - 10 PB - MDPI ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina T1 - Magnetically enhanced photoconductive high voltage control JF - ISSS Journal of Micro and Smart Systems N2 - The recent surge of interest in electrostatic actuators, particularly for soft robotic applications, has placed increasing demands on high voltage control technology. In this respect, optoelectronic bidirectional switching and analogue regulation of high voltages is becoming increasingly important. One common problem is the leakage current due to dark resistance of the material or device used. Another is the physical size of such elements. However, their ability to provide galvanic separation makes them a very attractive alternative to conventional (wired) semiconductor elements. This paper gives an overview of available methods and devices before introducing a concept based on the combination of photoresistive and magnetoresistive effects in Gallium Arsenide that are potentially applicable to other semiconductor materials. KW - GaAs KW - High voltage actuators KW - Magnetoresistance KW - Opto-sensors KW - Photoconduction KW - Soft robotics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30606 N1 - Corresponding author: Gareth J. Monkman VL - 11 SP - 317 EP - 328 PB - Springer Nature ER - TY - CHAP A1 - Diehl, Andreas A1 - Wolff, Lilli A1 - Fuhrmann, Thomas A1 - Niemetz, Michael A1 - Mörtlbauer, Stefanie A1 - Dirnberger, Sandra T1 - Compact Freshmen Welcome Seminar for Engineering Students T2 - Procedia - Social and Behavioral Sciences N2 - The Faculty of Electrical Engineering and Information Technology of the OTH Regensburg developed and implemented a compact freshmen seminar for the afternoon of the first day of study. The intention of this seminar is to help the freshmen during their transition between school and study without losing lecture time in the first semester. The concept was tested with one small study group at the beginning of the summer semester 2015. To rate the impact of the seminar and to find aspects for continuous improvement an evaluation method was developed and used. Due to the good student resonance during the first run, this introduction seminar was held again in the winter semester 2015/16. It is planned to integrate this seminar as a regular session for all freshmen of the faculty curriculum and monitor the long-term effects of student motivation and success. KW - Engineering Education KW - Freshmen Seminar Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-31034 N1 - Corresponding author: Thomas Fuhrmann IS - 228 SP - 45 EP - 52 PB - Elsevier ER - TY - JOUR A1 - Westner, Markus T1 - Rezension "Designed for Digital". BT - Ross, J. W., Beath, C. M., & Mocker, M. (2019). Designed for digital: How to architect your business for sustained success. The MIT Press. ISBN 978-0262042888 JF - HMD Praxis Der Wirtschaftsinformatik Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-38626 N1 - Corresponding author: Markus Westner PB - Springer Nature ER - TY - JOUR A1 - Grad, Marius A1 - Nadammal, Naresh A1 - Schultheiss, Ulrich A1 - Lulla, Philipp A1 - Noster, Ulf T1 - An Integrative Experimental Approach to Design Optimization and Removal Strategies of Supporting Structures Used during L-PBF of SS316L Aortic Stents JF - Applied Sciences N2 - One of the fundamental challenges in L-PBF of filigree geometries, such as aortic stents used in biomedical applications, is the requirement for a robust yet easily removable support structure that allows each component to be successfully fabricated without distortion. To solve this challenge, an integrative experimental approach was attempted in the present study by identifying an optimal support structure design and an optimized support removal strategy for this design. The specimens were manufactured using four different support structure designs based on the geometry exposed to the laser beam during the L-PBF. Support removal procedures included sand blasting (SB), glass bead blasting (GB), and electrochemical polishing (ECP). The two best-performing designs (line and cross) were chosen due to shorter lead times and lower material consumption. As an additional factor that indicates a stable design, the breaking load requirement to remove the support structures was determined. A modified line support with a 145° included angle was shown to be the best support structure design in terms of breaking load, material consumption, and manufacturing time. All three procedures were used to ensure residue-free support removal for this modified line support design, with ECP proving to be the most effective. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-25612 N1 - Corresponding author: Marius Grad VL - 11 IS - 19 SP - 1 EP - 22 PB - MPDL ER - TY - JOUR A1 - Sterner, Michael A1 - Specht, Michael T1 - Power-to-Gas and Power-to-X-The History and Results of Developing a New Storage Concept JF - Energies N2 - Germany's energy transition, known as 'Energiewende', was always very progressive. However, it came technically to a halt at the question of large-scale, seasonal energy storage for wind and solar, which was not available. At the end of the 2000s, we combined our knowledge of both electrical and process engineering, imitated nature by copying photosynthesis and developed Power-to-Gas by combining water electrolysis with CO2-methanation to convert water and CO2 together with wind and solar power to synthetic natural gas. Storing green energy by coupling the electricity with the gas sector using its vast TWh-scale storage facility was the solution for the biggest energy problem of our time. This was the first concept that created the term 'sector coupling' or 'sectoral integration'. We first implemented demo sites, presented our work in research, industry and ministries, and applied it in many macroeconomic studies. It was an initial idea that inspired others to rethink electricity as well as eFuels as an energy source and energy carrier. We developed the concept further to include Power-to-Liquid, Power-to-Chemicals and other ways to 'convert' electricity into molecules and climate-neutral feedstocks, and named it 'Power-to-X'at the beginning of the 2010s. KW - 100% renewable energy scenarios KW - CARBON RECYCLING SYSTEM KW - CO2 KW - eFuels KW - electric fuels KW - energy transition KW - hydrogen KW - methanation KW - METHANOL KW - Power-to-Gas KW - Power-to-Hydrogen KW - Power-to-Methane KW - Power-to-X KW - sector coupling KW - sectoral integration KW - TRANSPORTATION Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26202 N1 - Corresponding author: Michael Sterner VL - 14 IS - 20 PB - MDPI ER - TY - JOUR A1 - Schiek, Roland T1 - Excitation of nonlinear beams: from the linear Talbot effect through modulation instability to Akhmediev breathers JF - Optics express N2 - The smooth transition between stable, Talbot-effect-dominated and modulationally unstable nonlinear optical beam propagation is described as the superposition of oscillating, growing and decaying eigenmodes of the common linearized theory of modulation instability. The saturation of the instability in form of breather maxima is embedded between eigenmode growth and decay. This explains well the changes of beam characteristics when the input intensity increases in experiments on modulation instability and breather excitation in spatial-spatial experimental platforms. An increased accuracy of instability gain measurements, a variety of interesting nonlinear beam scenarios and a more selective and well-directed breather excitation are demonstrated experimentally. KW - DYNAMICS KW - FIBER KW - GENERATION KW - PEREGRINE SOLITON KW - SPATIAL SOLITONS KW - WAVE-GUIDE Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26049 N1 - Corresponding author: Roland Schiek VL - 29 IS - 10 SP - 15830 EP - 15851 PB - Optica Publishing Group CY - Washington, DC, USA ER - TY - JOUR A1 - Schildgen, Johannes T1 - Interaktive Vorlesungsfolien mit SQL-Unterstützung JF - Datenbank-Spektrum N2 - Mit PowerPoint oder LaTeX Beamer erstellte Vorlesungsfolien sind meist statisch und dienen hauptsächlich der Präsentation von Lehrinhalten. Als Alternative dazu werden drei Erweiterungen für das HTML- und JavaScript-basierte Präsentationsframework reveal.js vorgestellt, die für mehr Interaktion in der Datenbankenlehre sorgen sollen: (1) Eine Live-Ausführung von SQL-Anfragen und eine Darstellung des Anfrageergebnisses direkt auf der Folie; mit Möglichkeit zur Anpassung der Anfrage im Präsentationsbetrieb, (2) eine JSON-basierte Beschreibung von ER-Diagrammen, welche graphisch auf den Folien dargestellt werden sollen und (3) eingebettete Smartphone-Umfragen, um zwischendurch – ohne einen Kontextwechsel – Quiz-Fragen zu stellen. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26059 N1 - Corresponding author: Johannes Schildgen VL - 21 IS - 1 SP - 19 EP - 27 PB - Springer Nature ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Striegl, Birgit A1 - Prem, Nina A1 - Sindersberger, Dirk T1 - Electrical Properties of Magnetoactive Boron‐Organo‐Silicon Oxide Polymers JF - Macromolecular Chemistry and Physics N2 - The electrical properties of rheopectic magnetoactive composites comprising boron-organo-silicon oxide dielectric matrices containing carbonyl iron microparticles are presented for the first time. The increase in interfacial magnetocapacitance is seen to greatly exceed that experienced when using conventional elastomeric matrices such as polydimethylsiloxane. In addition to the increase in capacitance, a simultaneous and sharp decrease in the parallel electrical resistance over several orders of magnitude is also observed. The effects are time dependent but repeatable. Potential applications include magnetically controlled frequency dependent devices, magnetic sensor systems, weighting elements for neural networks, etc. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26488 N1 - Corresponding author: Gareth J. Monkman VL - 221 IS - 4 SP - 1 EP - 8 PB - Wiley ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Infrared spectral analysis of low concentration magnetoactive polymers JF - Journal of Applied Polymer Science N2 - This work concerns an area of magnetoactive polymer (MAP) research seldom considered. Traditionally only MAP with high concentrations of magnetic filler (typically between 10 and 90 wt%) have been investigated. This article deals with a hitherto neglected aspect of research, namely MAP containing lower magnetic filler concentrations (1 to 3 wt%). This article utilizes a range of spectroscopic analysis methods (Raman and FTIR) and their applicability to MAP characterization at wavelengths ranging from 2.5 to 25 mu m. Particular attention is paid to low carbonyl iron particle (CIP) concentrations in MAP for which the emergence of capillary doublets at a critical 2 wt% concentration is revealed. This results in measurable magnetic field-dependent changes in IR absorption at a wavelength of 4.255 mu m together with a detectable CO2 susceptibility. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48366. KW - ELASTOMERS KW - magnetism and magnetic properties KW - sensors and actuators KW - spectroscopy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-25913 SN - 1097-4628 N1 - Corresponding author: Nina Prem VL - 137 IS - 7 SP - 1 EP - 7 PB - Wiley ER - TY - JOUR A1 - Chow, Rosan T1 - Moving forward together JF - Strategic Design Research Journal Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-29007 N1 - corresponding author: Rosan Chow VL - 11 IS - 2 SP - 167 EP - 169 PB - OJS/PKP ER - TY - JOUR A1 - Müller, Max A1 - Rück, Thomas A1 - Jobst, Simon A1 - Pangerl, Jonas A1 - Weigl, Stefan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - An Algorithmic Approach to Compute the Effect of Non-Radiative Relaxation Processes in Photoacoustic Spectroscopy JF - Photoacoustics N2 - Successful transfer of photoacoustic gas sensors from laboratory to real-life applications requires knowledge about potential cross-sensitivities towards environmental and gas matrix changes. Multi-dimensional calibration in case of cross-sensitivities can become very complex or even unfeasible. To address this challenge, we present a novel algorithm to compute the collision based non-radiative efficiency and phase lag of energy relaxation on a molecular level (CoNRad) for photoacoustic signal calculation. This algorithmic approach allows to calculate the entire elaxation cascade of arbitrarily complex systems, yielding a theoretical photoacoustic signal. In this work the influence of varying bulk compositions, i.e. nitrogen (N2), oxygen (O2) and water (H2O) on the photoacoustic signal during methane (CH4) detection is demonstrated. The applicability of the algorithm to other photoacoustic setups is shown exemplary by applying it to the relaxational system investigated in [1]. Hayden et al. examined the effect of water on photoacoustic carbon monoxide (CO) detection. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-39935 N1 - Corresponding author: Max Müller VL - 26 PB - Elsevier ER - TY - JOUR A1 - Görtler, Michael T1 - Rechtspopulismus als (komplexe) Problemstellung der Sozialen Arbeit JF - Soziale Passagen : Journal für Empirie und Theorie Sozialer Arbeit N2 - Dieser Beitrag enthält Überlegungen zum Rechtspopulismus als (komplexe) Problemstellung der Sozialen Arbeit. Eine theoretisch-reflexive Analyse pädagogischer und didaktischer Ansätze, eine qualitative Analyse zu Herausforderungen und Bewältigungsstrategien von Fachkräften in der Kinder- und Jugendhilfe sowie eine Analyse aktueller Veröffentlichungen und Stellungnahmen im Kontext des Rechtspopulismus legen die Vermutung nahe, dass sich die Soziale Arbeit aufgrund der Komplexität dieses gesellschaftlichen und politischen Phänomens in einer Suchbewegung befindet. KW - Kinder- und Jugendhilfe KW - Padagogische und didaktische Ansätze KW - Soziale Arbeit KW - Rechtspopulismus KW - Politische Bildung KW - Professionalität Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-45323 N1 - Corresponding author: Michael Görtler VL - 14 SP - 193 EP - 199 PB - Springer Nature ER - 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 - Grad, Marius A1 - Nadammal, Naresh A1 - Tytko, Darius A1 - Noster, Ulf T1 - On the nanoindentation behavior of a TiC layer formed through thermo-reactive diffusion during hot pressing of Ti and cast iron JF - Materials Letters: X N2 - Hot pressing of pure Ti and cast iron under vacuum formed a ~15 μm wide TiC-layer through the thermoreactive diffusion process. Nanoindentation testing of the TiC-layer revealed average hardness and elastic modulus values of ~35 GPa and ~400 GPa, respectively. High-resolution indentation mapping indicated hardness change across the boundary with peak values observed within the TiC-layer. Solid state high temperature diffusion holds significant potential for developing uniform hard coatings on pure Ti/Ti-alloys. KW - Titanium alloys KW - Hard coating KW - Nanoindentation KW - Electron backscatter diffraction Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-50066 SN - 2590-1508 N1 - Corresponding author: Marius Grad VL - 15 IS - September SP - 1 EP - 4 PB - Elsevier CY - Amsterdam, Niederlande 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 - Haug, Sonja A1 - Schnell, Rainer A1 - Scharf, Anna A1 - Altenbuchner, Amelie A1 - Weber, Karsten T1 - Bereitschaft zur Impfung mit einem COVID-19-Vakzin - Risikoeinschätzung, Impferfahrungen und Einstellung zu Behandlungsverfahren JF - Prävention und Gesundheitsförderung N2 - Hintergrund Impfungen stellen eine bedeutende Präventionsmaßnahme dar. Grundlegend für die Eindämmung der Coronapandemie mittels Durchimpfung der Gesellschaft ist eine ausgeprägte Impfbereitschaft. Ziel der Arbeit Die Impfbereitschaft mit einem COVID‑19-Vakzin (Impfstoff gegen das Coronavirus) und deren Einflussfaktoren werden anhand einer Zufallsstichprobe der Gesamtbevölkerung in Deutschland untersucht. Material und Methoden Die Studie basiert auf einer telefonischen Zufallsstichprobe und berücksichtigt ältere und vorerkrankte Personen ihrem Bevölkerungsanteil entsprechend. Die Ein-Themen-Bevölkerungsbefragung zur Impfbereitschaft (n = 2014) wurde im November/Dezember 2020 durchgeführt. Ergebnisse Die Impfbereitschaft in der Stichprobe liegt bei rund 67 %. Vorerfahrungen mit Impfungen moderieren die Impfbereitschaft. Sie steigt bei Zugehörigkeit zu einer Risikogruppe. Der Glaube an die Wirksamkeit alternativer Heilmethoden und Befürwortung alternativer Behandlungsverfahren geht mit geringerer Impfbereitschaft einher. Ältere Menschen sind impfbereiter, kovariierend mit ihrer Einschätzung höherer Gefährdung bei Erkrankung. Ebenso ist die Ablehnung einer Impfung mit der Überschätzung von Nebenwirkungen assoziiert. Schlussfolgerung Die Impfbereitschaft hängt mit Impferfahrungen und Einstellungen zu Gesundheitsbehandlungsverfahren allgemein zusammen. Die Überschätzung der Häufigkeit ernsthafter Nebenwirkungen bei Impfungen weist auf weit verbreitete Fehlinformationen hin. T2 - Willingness to be vaccinated with a COVID‑19 vaccine—risk assessment, vaccination experiences and towards treatment procedures KW - Coronavirus-Impfung KW - Risikogruppe KW - Impfnebenwirkungen KW - Einstellung zu Medizin KW - Arztbesuche Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-154 N1 - Corresponding Author: Sonja Haug VL - 17 IS - 4 SP - 537 EP - 544 PB - Springer Nature ER - TY - JOUR A1 - Altenbuchner, Amelie A1 - Haug, Sonja A1 - Schnell, Rainer A1 - Scharf, Anna A1 - Weber, Karsten T1 - Impfbereitschaft von Eltern mit einem COVID-19-Vakzin BT - Die Rolle von Elternschaft und Geschlecht JF - Pädiatrie & Pädologie. Österreichische Zeitschrift für Kinder- & Jugendheilkunde N2 - Hintergrund: Eltern stehen im Rahmen der eigenen Impfung und der Kinderimpfung mit einem COVID-19-Vakzin vor einer Impfentscheidung. Zum aktuellen Zeitpunkt gibt es keine (vollständige) Impfempfehlung. Fragestellung: Die Studie untersucht die Impfbereitschaft von Eltern minderjähriger Kinder und Personen ohne minderjährige Kinder, wobei insbesondere Geschlechtsunterschiede überprüft werden. Methoden: Die Studie basiert auf einer Zufallsstichprobe (Telefon-Survey, n = 2014, Erhebung zwischen 12.11.2020 und 10.12.2020). Die Auswertung stützt sich insbesondere auf die Teilstichprobe von Personen mit minderjährigen Kindern im Haushalt (n = 461). Ergebnisse: Eltern weisen durchgängig eine geringere Impfbereitschaft mit einem COVID-19-Vakzin auf als Befragte ohne minderjährige Kinder (54,1 % vs. 71,1 %). Väter weisen eine stärker ausgeprägte eigene Impfbereitschaft auf als Mütter. Darüber hinaus sind Männer eher als Frauen bereit, das eigene Kind mit einem COVID-19-Vakzin impfen zu lassen. Schlussfolgerungen: Bei Eltern und insbesondere Müttern ist eine erhebliche Fehleinschätzung von Impfrisiken und häufiger Glaube an Impfverschwörungstheorien zu beobachten. Empfohlen werden anschauliche und leicht verständliche Informationen über die Wirkung und Nebenwirkungen der Impfung mit einem COVID-19-Vakzin durch zuständige Institutionen und Ärzte. T2 - Parentsʼ Willingness to Vaccinate with a COVID-19 Vaccine KW - Nebenwirkungen KW - Impfstoffverschwörungsglaube KW - Einstellung zu Homöopathie KW - Risikokommunikation KW - Impfberatung Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-196 N1 - Corresponding Author: Sonja Haug VL - 56 IS - 5 SP - 230 EP - 234 PB - Springer Nature ER - TY - JOUR A1 - Altenbuchner, Amelie A1 - Haug, Sonja A1 - Weber, Karsten T1 - Die ersten Schritte nach einer hüftnahen Fraktur BT - Sensorbasierte Bewegungsexploration bei geriatrischen Traumapatient/-innen JF - Zeitschrift für Gerontologie und Geriatrie N2 - Nach einer Fraktur ist Mobilisierung Behandlungsziel und Therapiesäule. Das Festlegen von Outcomes basiert jedoch auf vielen Unsicherheiten, da Assessments nicht für alle Patient/-innen geeignet sind. Sie können agesabhängig beeinflusst und subjektiv geprägt sein. Sensorbasiertes Bewegungsmonitoring bietet eine Ergänzung zur Operationalisierung der Gehfähigkeit. Für Längsschnittuntersuchungen, die auch im häuslichen Umfeld durchgeführt werden, eignet sich die tägliche Schrittzahl als Variable. Sie kann durch einen handelsüblichen Fitnesstracker beobachtet werden. T2 - The first steps after a proximal femoral fracture: Sensor-based mobility exploration in geriatric trauma patients KW - Schrittzahlen KW - Rehabilitation KW - Mobilität KW - Motion-Tracker KW - Alterstraumatologie Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-14251 SN - 0948-6704 N1 - Corresponding author: Amelie Altenbuchner VL - 54 SP - 555 EP - 560 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 - Thiel, Charlotte A1 - Kratzer, Johanna A1 - Grimm, Benedikt A1 - Kränkel, Thomas A1 - Gehlen, Christoph T1 - Effect of Internal Moisture and Outer Relative Humidity on Concrete Carbonation JF - CivilEng N2 - With steadily rising CO2 concentrations in the ambient air and fast-changing concretecompositions with reduced clinker contents, the availability of reliable and accelerated concrete car-bonation tests is of crucial importance to design durable structures. This paper focuses on the effectsof moisture under accelerated conditions and the effects of different CO2 exposure conditions. Mor-tar prisms incorporating three different cement types were cured and stored at either 50% or 65%relative humidity (RH). Afterwards, the prisms were carbonated at different ambient humidities(50, 57 and 65%), different CO2 concentrations (0.04, 1 and 3 vol.%) and complemented by a seriesof tests at increased gas pressure (2 barg). High-resolution test methods were used to explain theunderlying carbonation mechanisms. The results show that pre-conditioning for two weeks—ascurrently suggested by the European Standard—seems to be too short because the initial inner mois-ture content severely affects the carbonation rate. Relative humidity during carbonation of 57% ledto higher carbonation rates compared to 50% and 65%. In addition, climate data needs to be period-ically (preferably permanently) recorded in research experiments and in laboratory testing to ensurefair interpretation of experimental results. KW - accelerated carbonation KW - concrete KW - moisture KW - durability KW - relative humidity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-56091 N1 - Corresponding author: Charlotte Thiel VL - 4 IS - 3 SP - 1039 EP - 1052 PB - MDPI CY - Basel 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 - Schliermann, Rainer A1 - Rock, Jasmin A1 - Schroll-Decker, Irmgard T1 - Erwerb von sozialer und emotionaler Kompetenz im Bachelorstudium der Sozialen Arbeit: Eine explorative Annäherung JF - Zeitschrift für Bildungsforschung Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-59260 N1 - Corresponding author: Irmgard Schroll-Decker VL - 13 IS - 1 SP - 335 EP - 350 PB - Springer Nature 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 - Wiesent, Lisa A1 - Schultheiß, Ulrich A1 - Lulla, Philipp A1 - Nonn, Aida A1 - Noster, Ulf T1 - Mechanical properties of small structures built by selective laser melting 316 L stainless steel – a phenomenological approach to improve component design JF - Materials Science & Engineering Technology JF - Materialwissenschaft und Werkstofftechnik N2 - Experimental investigations are conducted to quantify the influence of specimen thickness and orientation on the mechanical properties of selective laser melted stainless steel 316 L. The results indicate that the mechanical strength and ductility increase with increasing specimen thickness until a saturation value is reached from a specimen thickness of about 2 mm. Specimen orientation dependency is pronounced for thin specimens (<1.5 mm), whereas only small deviations in strength are observed for thicker specimens with orientations of 30°, 45° and 90° to build direction. The mechanical properties of the specimen orientation of 0° to build direction shows great deviation to the other orientations and the smallest overall strength. A reliable design of selective laser melted components should account for specimen thickness and orientation, e. g. by a correction factor. Furthermore, it is recommended to avoid loads vertical (90°) and parallel (0°) to build direction to guarantee higher ductility and strength. T2 - Mechanische Eigenschaften von kleinen Strukturen aus selektiv lasergeschmolzenem 316 L Edelstahl – ein phänomenologischer Ansatz zur Verbesserung des Bauteildesigns Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-14718 N1 - Corresponding author: Lisa Wiesent VL - 51 IS - 12 SP - 1615 EP - 1629 PB - Wiley ER - TY - JOUR A1 - Haug, Sonja A1 - Vetter, Miriam T1 - Altersgerechtes Wohnen im Quartier JF - Standort - Zeitschrift für angewandte Geographie N2 - Im Alter nimmt das Quartier aufgrund geringerer Aktionsradien an Bedeutung zu. Der Beitrag befasst sich mit der Frage, welche Besonderheiten sich bei Senioren-Haushalten im Hinblick auf Wohnen und soziale Teilhabe zeigen. Aus dem Projekt MAGGIE werden Ergebnisse einer schriftlichen Haushaltsbefragung (N=195) in der Wohngenossenschaft Margaretenau Regensburg dargestellt. Hierbei wird auf die aktuelle und zukünftige Wohnsituation, den Veränderungsbedarf, den Wunsch nach Gemeinschaftsangeboten und die soziale Einbettung eingegangen. Es zeigt sich eine geringe Veränderungsbereitschaft und ein überdurchschnittlich hohes Maß an lokalem Sozialkapital. Am Ende werden Schlussfolgerungen für das Sanierungs- und Quartiersmanagement gezogen. T2 - Age-appropriate living in the neighborhood KW - Alter KW - Wohnen KW - Stadtviertel KW - Sozialraum KW - Senioren KW - Wohnsituation KW - Sozialraum KW - Lokales Sozialkapital KW - Quartiersgestaltung Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-20050 SN - 1432-220X N1 - Corresponding author: Sonja Haug VL - 45 SP - 11 EP - 17 PB - Springer Nature ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Striegl, Birgit A1 - Böhm, Valter A1 - Monkman, Gareth J. T1 - Shape memory effects using magnetoactive Boron-organo-silicon oxide polymers JF - Macromolecular Chemistry and Physics N2 - Thermomechanical shape memory materials have certain disadvantages when it comes to 3D volumetric reproduction intended for rapid prototyping or robotic prehension. The need to constantly supply energy to counteract elastic retraction forces in order to maintain the required geometry, together with the inability to achieve conformal stability at elevated temperatures, limits the application of thermal shape memory polymers. Form removal also presents problems as most viscoelastic materials do not ensure demolding stability. This work demonstrates how magnetoactive boron−organo−silicon oxide polymers under the influence of an applied magnetic field can be used to achieve energy free sustainable volumetric shape memory effects over extended periods. The rheopectic properties of boron−organo−silicon oxide materials sustain form removal without mold distortion. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-23205 N1 - Corresponding Author: Gareth J. Monkman VL - 221 IS - 15 SP - 1 EP - 8 PB - Wiley 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 - Maier, Robert A1 - Schlattl, Andreas A1 - Guess, Thomas A1 - Mottok, Jürgen T1 - CausalOps - Towards an industrial lifecycle for causal probabilistic graphical models JF - Information and Software Technology N2 - Context: Causal probabilistic graph-based models have gained widespread utility, enabling the modeling of cause-and-effect relationships across diverse domains. With their rising adoption in new areas, such as safety analysis of complex systems, software engineering, and machine learning, the need for an integrated lifecycle framework akin to DevOps and MLOps has emerged. Currently, such a reference for organizations interested in employing causal engineering is missing. This lack of guidance hinders the incorporation and maturation of causal methods in the context of real-life applications. Objective: This work contextualizes causal model usage across different stages and stakeholders and outlines a holistic view of creating and maintaining them within the process landscape of an organization. Method: A novel lifecycle framework for causal model development and application called CausalOps is proposed. By defining key entities, dependencies, and intermediate artifacts generated during causal engineering, a consistent vocabulary and workflow model to guide organizations in adopting causal methods are established. Results: Based on the early adoption of the discussed methodology to a real-life problem within the automotive domain, an experience report underlining the practicability and challenges of the proposed approach is discussed. Conclusion: It is concluded that besides current technical advancements in various aspects of causal engineering, an overarching lifecycle framework that integrates these methods into organizational practices is missing. Although diverse skills from adjacent disciplines are widely available, guidance on how to transfer these assets into causality-driven practices still need to be addressed in the published literature. CausalOps’ aim is to set a baseline for the adoption of causal methods in practical applications within interested organizations and the causality community. KW - Causal engineering KW - Model lifecycle KW - MLOps KW - Causal graphical models Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-73350 SN - 0950-5849 N1 - Corresponding author der OTH Regensburg: Robert Maier PB - Elsevier ER - TY - JOUR A1 - Haug, Sonja A1 - Altenbuchner, Amelie A1 - Weber, Karsten T1 - Elektronische Patientenakte und Freigabe von Gesundheitsdaten BT - Die Einstellung von Personen in Haushalten mit Kindern,The Attitude of Persons in Households with Children JF - Pädiatrie & Pädologie N2 - Hintergrund In Deutschland wird die elektronische Patientenakte (ePA) eingeführt. Fragestellung Untersucht werden Nutzungsbereitschaft der ePA, Einstellung zu Gesundheitsdaten und Datenübermittlung bei Personen mit und ohne Kinder. Methoden Telefonbefragung bei einer Zufallsstichprobe der Bevölkerung in Deutschland (2022, n = 1308). Ergebnisse Die ePA ist bei Haushalten mit Kindern mehrheitlich unbekannt. Ihre Nutzungsbereitschaft der ePA und die Zustimmung zur Speicherung von Gesundheitsdaten ist geringer, aber sie sind häufiger als Haushalte ohne Kinder bereit zur Freigabe ihrer Gesundheitsdaten für die Forschung. Schlussfolgerung Es besteht Aufklärungsbedarf über die Speicherung von Gesundheitsdaten. Gewünscht wird zunehmend eine digitale Arzt-Patienten-Kommunikation. KW - Gesundheitsregister KW - Elektronische Patientenakte KW - Forschungsdaten KW - Kommunikation im Gesundheitswesen KW - Versorgungsmanagement Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-73847 SN - 0030-9338 N1 - Corresponding author der OTH REgensburg: Sonja Haug PB - Springer ER - TY - JOUR A1 - Bauer, Franz A1 - Sterner, Michael T1 - Impacts of lifestyle changes on energy demand and greenhouse gas emissions in Germany JF - Renewable and Sustainable Energy Reviews N2 - Most energy scenario studies typically focus on technological options and fuel substitution for decarbonising future energy systems. Lifestyle changes are rarely considered, although they can significantly reduce energy demand and climate change mitigation efforts. By using an energy system model, this study shows that it is possible to reduce final energy demand in Germany by 61 % in 2050 relative to 2019 levels, resulting in an annual per capita energy demand of 44 GJ for a representative country of the Global North. This goal can be achieved through a combination of technological measures and lifestyle changes without sacrificing a decent standard of living. Societal chances can eliminate reliance on not-yet-established negative emission technologies, reduce energy dependency, and reduce the need for energy-intensive hydrogen and e-fuels. Downsizing the energy system provides an opportunity for strengthening climate change mitigation, decrease material demand and reduce land use. KW - Climate change mitigation KW - Energy system modelling KW - Sufficiency KW - Lifestyle changes KW - Climate neutrality KW - Low energy demand KW - German climate targets Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-77682 SN - 1364-0321 N1 - Corresponding author der OTH Regensburg: Franz Bauer VL - 207 PB - Elsevier CY - Amsterdam 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 - Escher, Lukas A1 - Rück, Thomas A1 - Jobst, Simon A1 - Pangerl, Jonas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photodissociation-Driven Photoacoustic Spectroscopy with UV-LEDs for Ozone Detection JF - Photoacoustics N2 - This study presents the development and evaluation of a UV-LED based photoacoustic (PA) measurement system for ozone (O3) detection to demonstrate its potential for low-cost and accurate sensing while for the first time addressing the importance of photodissociation for PA signal generation for O3 in the UV range. With a detection limit of 7.9 ppbV, the system exhibits a significant advancement over state-of-the-art UV-PA O3 detection and is on par with laser-based setups. Following a novel discussion of the PA signal arising from photodissociation and its products, cross-sensitivity effects due to environmental factors such as temperature and gas composition were systematically analyzed. A digital twin driven compensation for these influences was implemented and evaluated. Despite the challenges associated with modeling the effects of H2O and CO2, the PA system shows considerable potential, though further studies in real world applications must be conducted. KW - Photoacoustic spectroscopy KW - UV-LED KW - Ozone KW - Photodissociation KW - Cross-sensitivity Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-80076 SN - 2213-5979 N1 - Corresponding author der OTH Regensburg: Lukas Escher VL - 43 PB - Elsevier BV 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 - Kastenmeier, Andreas A1 - Siegl, Marco A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Review of elasto-static models for three-dimensional analysis of thick-walled anisotropic tubes JF - Journal of Composite Materials N2 - Most shell or beam models of anisotropic tubes under bending have no validity for thick-walled structures. As a result, the need to develop three-dimensional formulations which allow a change in the stress, strain and displacement distributions across the radial component arises. Basic formulations on three-dimensional anisotropic elasticity were made either stressor displacement-based by Lekhnitskii or Stroh on plates. Lekhnitskii also was the first to expand these analytical formulations to tubes under various loading conditions. This paper presents a review of the stress and strain analysis of tube models using three-dimensional anisotropic elasticity. The focus lies on layered structures, like fiber-reinforced plastics, under various bending loads, although the basic formulations and models regarding axisymmetric loads are briefly discussed. One section is also dedicated to the determination of an equivalent bending stiffness of tubes. KW - composite tube bending KW - layered structrues KW - anisotropy KW - Analytical modelling KW - elasticity Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-67521 N1 - Corresponding author: Andreas Kastenmeier PB - Sage 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 - Richter, Stefanie T1 - Erleben von Zukunftsunsicherheit, Armutsrisiken und prekären Lebenslagen im Pflegeheim JF - Zeitschrift für Gerontologie und Geriatrie N2 - Die Situation von Menschen im Pflegeheim, die besonders dem Risiko der „pflegebedingten Verarmung“ ausgesetzt sind, ist in der Forschung wenig präsent. Der Beitrag befasst sich mit dem Erleben von Unsicherheiten, Armut und prekären Lebenslagen älterer Menschen im Heim. Grundlage liefern Daten einer ethnographischen Studie zum Älterwerden und zum Leben mit chronischen Erkrankungen. Anhand von Fällen wird ein Spektrum prekärer Lebenslagen skizziert. Deutlich wird u. a.: Menschen mit diversen soziobiografischen Hintergründen können im Zuge von Hilfebedürftigkeit und Heimübergängen von Unsicherheiten, Armut und prekären Lebenslagen betroffen sein. Nicht zu wissen, ob das verfügbare Geld genügt, um Kostensteigerungen bis zum Lebensende zu decken, kennzeichnet eine häufig erlebte Zukunftsunsicherheit; drohende Armut bzw. die Abhängigkeit von Sozialhilfe können pflege- und institutionell bedingte Verlusterfahrungen von Autonomie, Teilhabe und Lebensgestaltung verschärfen und den Gesamtzustand weiter destabilisieren. Das Erleiden bleibt weitgehend unsichtbar; strukturelle Probleme werden individualisiert. N2 - The living situation of people in nursing homes, with a specific vulnerability to care-related impoverishment, is underresearched. This article deals with experiences of uncertainty, poverty and a precarious life situation of care home residents in later life. The data basis is supplied by an ethnographic study of ageing and living with chronic health conditions. A range of precarious living situations are outlined on the basis of real cases. Insights gleaned include: people with diverse sociobiographical backgrounds can be affected by insecurity, poverty and precarious life situations as a result of becoming dependent on help and the transition to care homes. Not knowing whether available funds will suffice to cover rising costs until the end of life is a common form of uncertainty about the future. The threat of poverty or becoming dependent on state benefits can exacerbate experiences of loss associated with institutional care, losing autonomy, opportunities for participation, and options for shaping oneʼs life and can further destabilize the overall condition. This anguish remains largely invisible; structural problems are individualized. KW - Altern KW - Hilfsbedürftigkeit KW - Heimübergang KW - Armut KW - Autonomie KW - aging KW - need of care KW - home transition KW - poverty KW - autonomy Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-64350 N1 - Corresponding author: Stefanie Richter SP - 1 EP - 6 PB - Springer ET - Online first ER - TY - JOUR A1 - Görtler, Michael T1 - Bildung und Zeit im Kontext der Sozialen Arbeit : Theoretische Überlegungen zur Bedeutung von Zeit für Bildungsprozesse im Kontext der Sozialen Arbeit JF - Sozial Extra N2 - Die Bedeutung von Zeit für Bildungsprozesse im Kontext der Sozialen Arbeit ist bisher wenig erforscht. Um sich dieser Fragestellung anzunähern, werden in diesem Beitrag theoretische Überlegungen im Anschluss an Diskurse zu Bildung und Zeit in der Pädagogik angestellt. Dabei wird Zeit als ermöglichender, ökonomischer und politischer Faktor diskutiert, um die Perspektive der Sozialen Arbeit auf Bildungsprozesse zu erweitern. T2 - Education and Time in the Context of Social Work : Theoretical Considerations about the Importance of Time for Educational Processes KW - Bildung und Zeit im Kontext der Sozialen Arbeit KW - Zeit als ermöglichender, ökonomischer und politischer Faktor in Bildungsprozessen KW - Education and time in the context of social work KW - Time as an enabling, economic and political factor in educational processes Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-60988 N1 - Corresponding author: Michael Görtler VL - 47 IS - 1 SP - 46 EP - 49 PB - Springer ER - TY - JOUR A1 - Pongratz, Christian A1 - Tix, Janek A1 - Wolfrum, Johannes A1 - Gerke, Steffen A1 - Ehrlich, Ingo A1 - Brünig, Michael T1 - Test Setup for Investigating the Impact Behavior of Biaxially Prestressed Composite Laminates JF - Experimental Techniques N2 - Instrumented impact testing and compression-after-impact testing are important to adequately qualify material behavior and safely design composite structures. However, the stresses to which fiber-reinforced plastic components are typically subjected in practice are not considered in the impact test methods recommended in guidelines or standards. In this paper, a test setup for investigating the impact behavior of composite specimens under plane uniaxial and biaxial preloading is presented. For this purpose, a special test setup consisting of a biaxial testing machine and a specially designed drop-weight tower was developed. The design decisions were derived from existing guidelines and standards with the aim of inducing barely visible impact damage in laminated carbon fiber-reinforced plastic specimens. Several measurement systems have been integrated into the setup to allow comprehensive observation of the impact event and specimen behavior. A feasibility test was performed with biaxially prestressed carbon fiber-reinforced plastic specimens in comparison with unstressed reference tests. The compressive-tensile prestressing resulted in lower maximum contact forces, higher maximum deflections, higher residual deflections and a different damage pattern, which was investigated by light microscopic analysis. Finally, the functionality of the experimental setup is discussed, and the results seem to indicate that the test setup and parameters were properly chosen to investigate the effect of prestresses on the impacts behavior of composite structures, in particular for barely visible subsequent damages. KW - Mechanical Engineering KW - Mechanics of Materials KW - Faserverbundwerkstoff KW - Schlagprüfung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-70355 SN - 0732-8818 N1 - Corresponding authors: Christian Pongratz und Ingo Ehrlich PB - Springer Nature 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 - Altmann, Matthias A1 - Schlegl, Peter A1 - Volbert, Klaus T1 - A low-power wireless system for energy consumption analysis at mains sockets JF - EURASIP Journal on Embedded Systems N2 - Introduction: Improving energy efficiency and reducing energy wastage is an important topic of our time. But it is quite difficult to figure out how much of our total electricity bill can be mapped to which device or at what time the device used it. We believe energy efficiency of normal households can be improved, if this kind of transparency would be available. In this article, we present a system for energy measurement at mains sockets to gain a transparent view of energy consumption for each device in a household. It consists of several smart energy measuring devices (SEMDs) that use a low-power radio protocol to dynamically build and connect to a radio network to transfer power usage date to a server. At the server, the data is stored and can be accessed via web interface. Results: Our primary goal was to build a back-end system for an energy metering platform with very low energy consumption. This platform can provide data for a variety of services that enables users (the consumers) to understand and improve their energy consumption behavior and increase overall energy efficiency of their households. KW - Low power KW - Smart grid KW - Smart home KW - Smart metering KW - Wireless system Y1 - 2017 U6 - https://doi.org/10.1186/s13639-016-0041-y N1 - Corresponding author: Peter Schlegl IS - 1 PB - Springer Nature ER - TY - JOUR A1 - Auer, Simon A1 - Schiebl, Jonas A1 - Iversen, Kristoffer A1 - Subhash Chander, Divyaksh A1 - Damsgaard, Michael A1 - Dendorfer, Sebastian T1 - Biomechanical assessment of the design and efficiency of occupational exoskeletons with the AnyBody Modeling System JF - Zeitschrift für Arbeitswissenschaften N2 - Exoskeletons were invented over 100 years ago but have only become popular in the last two decades, especially in the working industry as they can decrease work-related loads significantly. The most often used exoskeletons are for the lower back and shoulder since these are commonly affected body regions. All devices have in common that their purpose is to reduce internal loads of vulnerable body regions. Nevertheless, there is still little understanding on how biomechanical loading in the human body changes when exoskeletons are used. Therefore, further analyses are needed. A promising candidate for these are musculoskeletal models, which are based on an inverse dynamics approach and can calculate external parameters such as ground reaction forces or other interaction forces as well as internal parameters such as joint reaction forces or muscle activities. The various examples in the literature show that these models are increasingly used for assessing the biomechanical effects of exoskeletons on the human body. Furthermore, musculoskeletal models can calculate biomechanical loadings of humans with and without exoskeletons for all kinds of applications and allow an evaluation of their purpose. Practical Relevance: This article highlights the possibilities of musculoskeletal models for assessing the design and efficiency of occupational exoskeletons. Several practical use cases are described along with distinct descriptions of common implications of musculoskeletal and exoskeleton modeling. KW - Biomechanics KW - Ergonomics KW - Motion capture KW - Inverse dynamics Y1 - 2022 U6 - https://doi.org/10.1007/s41449-022-00336-4 N1 - Corresponding author: Sebastian Dendorfer VL - 76 IS - 4 SP - 440 EP - 449 PB - Springer Nature ER - TY - JOUR A1 - Melzner, Maximilian A1 - Pfeiffer, Christian A1 - Suess, Franz A1 - Dendorfer, Sebastian T1 - Musculoskeletal simulation of elbow stability for common injury patterns JF - Journal of Orthopaedic Research N2 - Elbow stability is derived from a combination of muscular, ligamentous, and bony structures. After an elbow trauma the stability of the joint is an important decision criterion for the subsequent treatment. The decision regarding non-operative/operative care depends mostly on subjective assessments of medical experts. Therefore, the aim of this study is to use musculoskeletal simulations as an objective assessment tool to investigate the extent to which failure of different stabilizers affects the elbow stability and how these observations correspond to the assessment from clinical practice. A musculoskeletal elbow simulation model was developed for this aim. To investigate the stability of the elbow, varus/valgus moments were applied under 0°, 45°and 90° flexion while the respective cubital angle was analyzed. This was performed for nine different injury scenarios, which were also evaluated for stability by clinical experts. With the results, it can be determined by which injury pattern and under which flexion angle the elbow stability is impaired regarding varus/valgus moments. The scenario with a complete failure of the medial and lateral ligaments and a fracture of the radial head was identified as having the greatest instability. The study presented a numerical determination of elbow stability against varus/valgus moments regarding clinical injury patterns, as well as a comparison of the numerical outcome with experience gained in clinical practice. The numerical predictions agree well with the assessments of the clinical specialists. Thus, the results from musculoskeletal simulation can make an important contribution to a more objective assessment of the elbow stability. KW - AnyBody KW - musculoskeletal simulation KW - elbow stability Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-54819 SN - 1554-527X N1 - Corresponding author: Maximilian Melzner VL - 41 IS - 6 SP - 1356 EP - 1364 PB - Wiley ER - TY - JOUR A1 - Reinker, Lukas A1 - Bläsing, Dominic A1 - Bierl, Rudolf A1 - Ulbricht, Sabina A1 - Dendorfer, Sebastian T1 - Correlation of Acceleration Curves in Gravitational Direction for Different Body Segments during High-Impact Jumping Exercises JF - sensors N2 - Osteoporosis is a common disease of old age. However, in many cases, it can be very well prevented and counteracted with physical activity, especially high-impact exercises. Wearables have the potential to provide data that can help with continuous monitoring of patients during therapy phases or preventive exercise programs in everyday life. This study aimed to determine the accuracy and reliability of measured acceleration data at different body positions compared to accelerations at the pelvis during different jumping exercises. Accelerations at the hips have been investigated in previous studies with regard to osteoporosis prevention. Data were collected using an IMU-based motion capture system (Xsens) consisting of 17 sensors. Forty-nine subjects were included in this study. The analysis shows the correlation between impacts and the corresponding drop height, which are dependent on the respective exercise. Very high correlations (0.83–0.94) were found between accelerations at the pelvis and the other measured segments at the upper body. The foot sensors provided very weak correlations (0.20–0.27). Accelerations measured at the pelvis during jumping exercises can be tracked very well on the upper body and upper extremities, including locations where smart devices are typically worn, which gives possibilities for remote and continuous monitoring of programs. KW - osteoporosis KW - inertial measurement units KW - wearable motion-tracking sensors KW - high-impact exercisess Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-58217 N1 - Corresponding author: Lukas Reinker N1 - This work was supported by the Bavarian Academic Forum [BayWISS-Verbundkolleg Gesundheit] and the DHZK fond for behavioral cardiovascular diseases [Behaviorale kardiovaskuläre Erkrankungen; grand number: 81Z0400105]. VL - 23 IS - 4 PB - MDPI CY - Basel 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 - Melzner, Maximilian A1 - Suess, Franz A1 - Dendorfer, Sebastian T1 - The impact of anatomical uncertainties on the predictions of a musculoskeletal hand model – a sensitivity study JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - Outputs of musculoskeletal models should be considered probabilistic rather than deterministic as they are affected by inaccuracies and estimations associated with the development of the model. One of these uncertainties being critical for modeling arises from the determination of the muscles' line of action and the physiological cross-sectional area. Therefore, the aim of this study was to evaluate the outcome sensitivity of model predictions from a musculoskeletal hand model in comparison to the uncertainty of these input parameters. For this purpose, the kinematics and muscle activities of different hand movements (abduction of the fingers, abduction of the thumb, and flexion of the thumb) were recorded. One thousand simulations were calculated for each movement using the Latin hypercube sampling method with a corresponding variation of the muscle origin/insertion points and the cross-sectional area. Comparing the standard hand to simulations incorporating uncertainties of input parameters shows no major deviations in on- and off-set time point of muscle activities. About 60% of simulations are located within a ± 30% interval around the standard model concerning joint reaction forces. The comparison with the variation of the input data leads to the conclusion that the standard hand model is able to provide not over-scattered outcomes and, therefore, can be considered relatively stable. These results are of practical importance to the personalization of a musculoskeletal model with subject-specific bone geometries and hence changed muscle line of action. KW - Biomechanik KW - Simulation Y1 - 2021 U6 - https://doi.org/10.1080/10255842.2021.1940974 SN - 1476-8259 N1 - Corresponding author: Maximilian Melzner VL - 25 IS - 2 SP - 156 EP - 164 PB - Taylor & Francis ER - TY - JOUR A1 - Melzner, Maximilian A1 - Engelhardt, Lucas A1 - Simon, Ulrich A1 - Dendorfer, Sebastian T1 - Electromyography-Based Validation of a Musculoskeletal Hand Model JF - Journal of Biomechanical Engineering N2 - Regarding the prevention of injuries and rehabilitation of the human hand, musculoskeletal simulations using an inverse dynamics approach allow for insights of the muscle recruitment and thus acting forces on the hand. Currently, several hand models from various research groups are in use, which are mainly validated by the comparison of numerical and anatomical moment arms. In contrast to this validation and model-building technique by cadaver studies, the aim of this study is to further validate a recently published hand model [1] by analyzing numerically calculated muscle activities in comparison to experimentally measured electromyographical signals of the muscles. Therefore, the electromyographical signals of 10 hand muscles of five test subjects performing seven different hand movements were measured. The kinematics of these tasks were used as input for the hand model, and the numerical muscle activities were computed. To analyze the relationship between simulated and measured activities, the time difference of the muscle on- and off-set points was calculated, which resulted in a mean on- and off-set time difference of 0.58 s between the experimental data and the model. The largest differences were detected for movements that mainly addressed the wrist. One major issue comparing simulated and measured muscle activities of the hand is cross-talk. Nevertheless, the results show that the hand model fits the experiment quite accurately despite some limitations and is a further step toward patient-specific modeling of the upper extremity. KW - Elektromyographie KW - Biomechanik KW - Simulation KW - Electromyography KW - Muscle KW - Musculoskeletal system KW - Signals KW - Simulation Y1 - 2021 U6 - https://doi.org/10.1115/1.4052115 VL - 144 IS - 2 PB - American Society of Mechanical Engineers, ASME ER - TY - JOUR A1 - Saffert, Anne-Sophie A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Biomechanical analysis of the right elevated glenohumeral joint in violinists during legato-playing JF - Technology and Health Care N2 - BACKGROUND: Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements. OBJECTIVE: For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture. METHODS: Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position. RESULTS: The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture. CONCLUSIONS: Elevating the right shoulder while playing the violin may pose a potential problem. KW - Biomechanische Analyse KW - Schultergelenk KW - Verletzung KW - Violinspiel KW - biomechanics KW - violin KW - shoulder elevation KW - shoulder joint force KW - musculoskeletal disease Y1 - 2022 U6 - https://doi.org/10.3233/THC-219001 N1 - Corresponding author: Anne-Sophie Saffert VL - 30 IS - 1 SP - 177 EP - 186 PB - IOS Press 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 - Diermeier, Andreas A1 - Sindersberger, Dirk A1 - Krenkel, Lars A1 - Rosell, X. C. A1 - Monkman, Gareth J. T1 - Controllable Magnetoactive Polymer Conduit JF - The Open Mechanical Engineering Journal N2 - Objective: Magneto-active Polymers (MAP) are smart materials whose mechanical characteristics, such as elastic and shear moduli, may be controllable by means of an externally applied magnetic field. Methods: Various additives may be used to influence the characteristics of the polymer matrix whilst a suspension of soft and/or hard magnetic particles determine the magnetic properties of the composite. Both pre-cure and post-cure magnetization is possible. Results: A range of control strategies have been investigated for evaluation of the system using fluids of differing kinematic viscosity. Conclusion: Depending on the degree of magnetic field homogeneity, magneto-deformation and magnetostriction contribute to MAP actuation. This paper presents a novel application in the form of a peristaltic MAP tube system, applicable to flow control and pumping of hemorheological fluids in blood circulatory systems for biomedical research purposes. Y1 - 2018 UR - https://www.benthamopen.com/ABSTRACT/TOMEJ-12-192 N1 - Corresponding authro: Gareth J. Monkman VL - 12 IS - 1 SP - 192 EP - 200 PB - Bentham 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 - Hornberger, Helga A1 - Kissel, Hannah A1 - Striegl, Birgit A1 - Kronseder, Matthias A1 - Vollnhals, Florian A1 - Christiansen, Silke H. T1 - Bioactivity and corrosion behavior of magnesium barrier membranes JF - Materials and Corrosion N2 - In the current research, magnesium and its alloys have been intensively studied as resorbable implant materials. Magnesium materials combine their good mechanical properties with bioactivity, which make them interesting for guided bone regeneration and for the application as barrier membranes. In this study, the in vitro degradation behavior of thin magnesium films was investigated in cell medium and simulated body fluid. Three methods were applied to evaluate corrosion rates: measurements of (i) the gaseous volume evolved during immersion, (ii) volume change after immersion, and (iii) polarization curves. In this comparison, measurements of H2 development in Dulbecco's modified Eagle's medium showed to be the most appropriate method, exhibiting a corrosion rate of 0.5 mm·year−1. Observed oxide and carbon contamination have a high impact on controlled degradation, suggesting that surface treatment of thin foils is necessary. The bioactivity test showed positive results; more detailed tests in this area are of interest. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-24499 N1 - Corresponding author: Helga Hornberger VL - 73 IS - 1 SP - 8 EP - 19 PB - Wiley ER - TY - JOUR A1 - Stelzer, Vera A1 - Krenkel, Lars T1 - 2D numerical investigations derived from a 3D dragonfly wing captured with a high-resolution micro-CT JF - Technology and health care : official journal of the European Society for Engineering and Medicine N2 - BACKGROUND: Due to their corrugated profile, dragonfly wings have special aerodynamic characteristics during flying and gliding. OBJECTIVE: The aim of this study was to create a realistic 3D model of a dragonfly wing captured with a high-resolution micro-CT. To represent geometry changes in span and chord length and their aerodynamic effects, numerical investigations are carried out at different wing positions. METHODS: The forewing of a Camacinia gigantea was captured using a micro-CT. After the wing was adapted an error-free 3D model resulted. The wing was cut every 5 mm and 2D numerical analyses were conducted in Fluent® 2020 R2 (ANSYS, Inc., Canonsburg, PA, USA). RESULTS: The highest lift coefficient, as well as the highest lift-to-drag ratio, resulted at 0 mm and an angle of attack (AOA) of 5∘. At AOAs of 10∘ or 15∘, the flow around the wing stalled and a Kármán vortex street behind the wing becomes CONCLUSIONS: The velocity is higher on the upper side of the wing compared to the lower side. The pressure acts vice versa. Due to the recirculation zones that are formed in valleys of the corrugation pattern the wing resembles the form of an airfoil. KW - aerodynamics KW - computational fluid dynamics KW - Dragonfly wing KW - gliding flight KW - insect flight Y1 - 2022 U6 - https://doi.org/10.3233/THC-219010 N1 - Corresponding author: Vera Stelzer VL - 30 IS - 1 SP - 283 EP - 289 PB - IOS Press ER - TY - JOUR A1 - Tauwald, Sandra Melina A1 - Michel, Johanna A1 - Brandt, Marie A1 - Vielsmeier, Veronika A1 - Stemmer, Christian A1 - Krenkel, Lars T1 - Experimental studies and mathematical modeling of the viscoelastic rheology of tracheobronchial mucus from respiratory healthy patients JF - Multidisciplinary Respiratory Medicine N2 - BACKGROUND: Tracheobronchial mucus plays a crucial role in pulmonary function by providing protection against inhaled pathogens. Due to its composition of water, mucins, and other biomolecules, it has a complex viscoelastic rheological behavior. This interplay of both viscous and elastic properties has not been fully described yet. In this study, we characterize the rheology of human mucus using oscillatory and transient tests. Based on the transient tests, we describe the material behavior of mucus under stress and strain loading by mathematical models. METHODS: Mucus samples were collected from clinically used endotracheal tubes. For rheological characterization, oscillatory amplitude-sweep and frequency-sweep tests, and transient creep-recovery and stress-relaxation tests were performed. The results of the transient test were approximated using the Burgers model, the Weibull distribution, and the six-element Maxwell model. The three-dimensional microstructure of the tracheobronchial mucus was visualized using scanning electron microscope imaging. RESULTS: Amplitude-sweep tests showed storage moduli ranging from 0.1 Pa to 10000 Pa and a median critical strain of 4 %. In frequency-sweep tests, storage and loss moduli increased with frequency, with the median of the storage modulus ranging from 10 Pa to 30 Pa, and the median of the loss modulus from 5 Pa to 14 Pa. The Burgers model approximates the viscoelastic behavior of tracheobronchial mucus during a constant load of stress appropriately (R2 of 0.99), and the Weibull distribution is suitable to predict the recovery of the sample after the removal of this stress (R2 of 0.99). The approximation of the stress-relaxation test data by a six-element Maxwell model shows a larger fit error (R2 of 0.91). CONCLUSIONS: This study provides a detailed description of all process steps of characterizing the rheology of tracheobronchial mucus, including sample collection, microstructure visualization, and rheological investigation. Based on this characterization, we provide mathematical models of the rheological behavior of tracheobronchial mucus. These can now be used to simulate mucus flow in the respiratory system through numerical approaches. KW - tracheobronchial mucus KW - rheological model KW - viscoelasticity Y1 - 2023 U6 - https://doi.org/10.4081/mrm.2023.923 SN - 2049-6958 N1 - Corresponding author: Sandra Melina Tauwald VL - 18 IS - 1 PB - PAGEPress CY - Pavia, Italy ER - TY - JOUR A1 - Kriegl, Raphael A1 - Krenkel, Lars A1 - Shamonin (Chamonine), Mikhail T1 - Preservation of wetting ridges using field-induced plasticity of magnetoactive elastomers JF - Journal of Colloid and Interface Science N2 - Hypothesis. The presence of a wetting ridge is crucial for many wetting phenomena on soft substrates. Conventional experimental observations of a wetting ridge require permanent presence of a droplet. The magnetic field-induced plasticity effect (FIPE) of soft magnetoative elastomers (MAEs) allows one to overcome this limitation. Depositing a droplet onto an MAE surface and applying a magnetic field fixes the wetting ridge in place due to the FIPE. The droplet can be removed to investigate the ridge with ease using conventional optical methods. Experiments. The wetting ridge is observed on MAEs with different shear moduli and different material thicknesses by confocal laser scanning microscopy (LSM). The preservation quality of the ridge is analyzed for several values of magnetic field from 10 mT to 270 mT. To verify the plausibilty of results obtained, the measured shape is compared to a theoretical model by Style & Dufresne. Findings. Upon removal of the sessile droplet, the deformation remains embossed onto the MAE surface as long as the magnetic field remains applied. The height of the ridge peak on soft samples (effective shear modulus kPa) is close to the theoretical prediction for a magnetic flux density of 50 mT. The magnitude of the external magnetic field magnifies the height of the wetting ridge. KW - Wetting ridge KW - Droplet KW - Magnetoactive elastomer KW - Magnetorheological elastomer KW - Field-induced plasticity KW - Confocal laser scanning microscopy Y1 - 2025 U6 - https://doi.org/10.1016/j.jcis.2024.12.132 SN - 0021-9797 N1 - Corresponding author der OTH Regensburg: Raphael Kriegl VL - 683 SP - 1019 EP - 1027 PB - Elsevier ER - TY - JOUR A1 - Kloiber, Jessica A1 - Anetsberger, Viktoria A1 - Schultheiß, Ulrich A1 - Hornberger, Helga T1 - High quality surfaces of magnesium alloy AZ31 by adjusting appropriate electropolishing parameters JF - Electrochimica Acta Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79298 N1 - Corresponding author der OTH Regensburg: Jessica Kloiber VL - 513 PB - Elsevier ER - TY - JOUR A1 - Kloiber, Jessica A1 - Schultheiß, Ulrich A1 - Hornberger, Helga T1 - Impact of heat treatment on the surface quality of electropolished WE43 alloy JF - Materials Letters N2 - In this study, the Mg alloy WE43 was solution annealed and precipitation hardened prior to electropolishing to evaluate the effects of different microstructures on the electropolishing result. While coarsely distributed precipitates led to surfaces showing wavy structures and dents after electropolishing, a uniform microstructure resulted in an even finish of the surface. The homogenization and refinement of the microstructure by heat treatment is a method to ensure improved electropolished surfaces of Mg materials Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-83512 SN - 0167-577X N1 - Corresponding author der OTH Regensburg: Jessica Kloiber VL - 397 PB - Elsevier BV 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 - Wiesent, Lisa A1 - Schultheiß, Ulrich A1 - Lulla, Philipp A1 - Noster, Ulf A1 - Schratzenstaller, Thomas A1 - Schmid, Christof A1 - Nonn, Aida A1 - Spear, Ashley T1 - Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents JF - PLoS ONE N2 - Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures. KW - Heat treatment KW - Lasers KW - Surface treatments KW - Specimen preparation and treatment KW - Material properties KW - Stiffness KW - Deformation KW - Powders KW - Koronarendoprothese KW - Rapid prototyping KW - Numerische Methode Y1 - 2020 U6 - https://doi.org/10.1371/journal.pone.0244463 N1 - Corresponding author: Lisa Wiesent VL - 15 IS - 12 SP - 1 EP - 30 PB - PLOS 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 - Thema, Martin A1 - Weidlich, Tobias A1 - Hörl, Manuel A1 - Bellack, Annett A1 - Mörs, Friedemann A1 - Hackl, Florian A1 - Kohlmayer, Matthias A1 - Gleich, Jasmin A1 - Stabenau, Carsten A1 - Trabold, Thomas A1 - Neubert, Michael A1 - Ortloff, Felix A1 - Brotsack, Raimund A1 - Schmack, Doris A1 - Huber, Harald A1 - Hafenbradl, Doris A1 - Karl, Jürgen A1 - Sterner, Michael T1 - Biological CO2-Methanation: An Approach to Standardization JF - Energies N2 - Power-to-Methane as one part of Power-to-Gas has been recognized globally as one of the key elements for the transition towards a sustainable energy system. While plants that produce methane catalytically have been in operation for a long time, biological methanation has just reached industrial pilot scale and near-term commercial application. The growing importance of the biological method is reflected by an increasing number of scientific articles describing novel approaches to improve this technology. However, these studies are difficult to compare because they lack a coherent nomenclature. In this article, we present a comprehensive set of parameters allowing the characterization and comparison of various biological methanation processes. To identify relevant parameters needed for a proper description of this technology, we summarized existing literature and defined system boundaries for Power-to-Methane process steps. On this basis, we derive system parameters providing information on the methanation system, its performance, the biology and cost aspects. As a result, three different standards are provided as a blueprint matrix for use in academia and industry applicable to both, biological and catalytic methanation. Hence, this review attempts to set the standards for a comprehensive description of biological and chemical methanation processes. KW - Biological methanation KW - bubble column reactor KW - CO2-methanation KW - CSTR KW - membrane reactor KW - methanation KW - Power-to-Gas KW - Power-to-Methane KW - standardization KW - Trickle-bed reactor Y1 - 2019 U6 - https://doi.org/10.3390/en12091670 N1 - Corresponding author: Martin Thema VL - 12 IS - 9 SP - 1 EP - 32 PB - MDPI ER - TY - JOUR A1 - Weigl, Stefan A1 - Feldmeier, Florian A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photoacoustic detection of acetone in N2 and synthetic air using a high power UV LED JF - Sensors Actuators B Chemical N2 - The performance of a photoacoustic trace gas sensor for the detection of acetone in N2 and synthetic air is reported. The sensor system utilises an amplitude modulated UV LED. The light source has an emission maximum at 278 nm and a maximum CW output power of 300 mW according to the datasheet. Three different collimating and focusing approaches have been investigated to guide the highly divergent LED light into the acoustic resonator of the photoacoustic measurement cell. A 3D printed aluminium cell was designed to optimize light coupling by simultaneously minimizing the photoacoustic background signal generation. Hence, the diameter of the resonator was set to a comparable large diameter of 10 mm and the inner walls of the resonator were mirror polished. The additive manufacturing procedure allowed for integration of a spirally formed gas channel, enabling gas heating prior to detection. The sensor performance was investigated by measuring acetone in N2 and synthetic air at different concentrations. The UV LED current was set to 86 % of the maximum value according to the datasheet of the light source in order to increase the lifetime and thermal stability. An Allan-Werle deviation analysis validates a stable sensor performance. The limit of detection (LoD) was determined at a 3σ noise level with a 10 s lock-in amplifier time constant by sampling data points over 20 s with a data acquisition rate of 5 Hz. LoDs of 80.8 ppbV and 19.6 ppbV were obtained for acetone in N2 and synthetic air, respectively. KW - Acetone detection KW - Photoacoustic spectroscopy KW - High power UV LED KW - UV LED collimation system KW - Acetone breath analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.snb.2020.128109 N1 - Corresponding author at: Sensorik-Applikationszentrum (SappZ) der Ostbayerischen Technischen Hochschule Regensburg VL - 316 IS - August SP - 1 EP - 11 PB - Elsevier ER - TY - JOUR A1 - Weigl, Stefan A1 - Wittmann, Elisabeth A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Effects of ambient parameters and cross-sensitivities from O2, CO2 and H2O on the photoacoustic detection of acetone in the UV region JF - Sensors Actuators B Chemical N2 - We present a sensitive UV LED photoacoustic setup for the detection of gaseous acetone and discuss its applicability towards breath analysis. We investigated the performance of the sensor for low acetone concentrations down to 0.1 parts per million (ppmV). The influences of temperature, flow, pressure, optical power and LED duty cycle on the measured signal have been examined. To gain a better understanding of the different effects on the photoacoustic signal, correlation analysis was applied and feature importance was determined using a large measured dataset. Furthermore, the cross-sensitivities towards O2, CO2 and H2O have been studied extensively. Finally, the sensor’s performance to detect acetone between 0.1–1 ppmV within gas mixtures simulating breath exhale conditions has been investigated, too. With a limit of detection (LoD) of 12.5 parts per billion (ppbV) (3σ) measured under typical breath exhale gas mixture conditions, the sensor demonstrated a high potential for the application of acetone detection in human breath analysis. KW - Acetone detection KW - Photoacoustic spectroscopy KW - High power UV LED KW - Cross-sensitivities KW - Acetone breath analysis Y1 - 2021 U6 - https://doi.org/10.1016/j.snb.2020.129001 SN - 0925-4005 N1 - Corresponding authors: Stefan Weigl, Elisabeth Wittmann, Thomas Rück, Rudolf Bierl, Frank-Michael Matysik N1 - Corrigendum to “Effects of ambient parameters and cross-sensitivities from O2, CO2 and H2O on the photoacoustic detection of acetone in the UV region” [Sens. Actuators B: Chem. 328 (February 2021) (2020) 129001]; https://doi.org/10.1016/j.snb.2020.129392 IS - 328 PB - Elsevier ER - TY - CHAP A1 - Haug, Sonja A1 - Vetter, Miriam ED - Teti, Andrea T1 - Ältere Menschen im Wohnquartier Margaretenau in Regensburg – aktuelle Situation und zukünftiger Bedarf T2 - Wohnen und Gesundheit im Alter T2 - Vechtaer Beiträge zur Gerontologie N2 - Der Beitrag zeigt Ergebnisse einer Begleitstudie zur Restaurierung und energetischen Modernisierung des historischen genossenschaftlichen Wohnquartiers Margaretenau in Regensburg im Projekt MAGGIE. Bei der Gestaltung von Wohnungen und Gelegenheiten für die soziale Einbettung im Quartier wird eine altersgerechte Perspektive eingenommen. Die Darstellung der schriftlichen standardisierten Haushaltsbefragung (n = 195) nimmt die Lebenssituation älterer Menschen ab 65 Jahren in den Fokus. Dazu werden die Themenbereiche Haushaltsstruktur, altersgerechtes Wohnen und Gemeinschaftseinrichtungen präsentiert. Neben der aktuellen Wohnsituation wurden Pläne und Wünsche für das zukünftige Wohnen abgefragt. Im Alter schwindet die Bereitschaft für Veränderungen, was sich am Wunsch zum Altern in der bisherigen Wohnung und Verbleib im Wohnquartier zeigt. Das Interesse am barrierereduzierten Wohnen ist bei älteren Haushalten geringer als bei jüngeren. Es zeigt sich ein überdurchschnittlich hohes Maß an lokalem Sozialkapital, wobei kein signifikanter Unterschied zwischen jüngeren und älteren Haushalten besteht. Y1 - 2022 SN - 978-3-658-34385-9 U6 - https://doi.org/10.1007/978-3-658-34386-6_14 N1 - Corresponding author: Sonja Haug SP - 215 EP - 227 PB - Springer VS CY - Wiesbaden ER - TY - CHAP A1 - Currle, Edda A1 - Haug, Sonja T1 - Acceptance of Telepresence Robotics, Telecare and Teletherapy Among Stroke Patients, Relatives and Therapy Staff T2 - dHealth 2024: proceedings of the 18th annual conference on Health Informatics meets Digital Health conference N2 - Background: Stroke as a cause of disability in adulthood causes an increasing demand for therapy and care services, including telecare and teletherapy. Objectives: Aim of the study is to analyse the acceptance of telepresence robotics and digital therapy applications. Methods: Longitudinal study with a before and after survey of patients, relatives and care and therapy staff. Results: Acceptance of the technology analysed is high in all three groups. Although acceptance among patients declined in parts of the cases in the second survey after having used telerobotics, all in all approval ratings remained high. With regard to patients no significant correlation was found between the general technology acceptance and the acceptance of use of telerobotics. Conclusion: Accepted new telecare and teletherapies can be offered with the help of telepresence robotics. This requires knowledge of and experience with the technology. Y1 - 2024 SN - 978-1-64368-517-5 U6 - https://doi.org/10.3233/SHTI240005 SN - 0926-9630 N1 - Corresponding Author: Edda Currle SP - 15 EP - 21 PB - IOS Press ER - TY - JOUR A1 - Haug, Sonja A1 - Lochner, Susanne A1 - Huber, Dominik T1 - Methodological Aspects of a Quantitative and Qualitative Survey of Asylum Seekers in Germany BT - A Field Report JF - mda - methods data analyses N2 - This field report presents and discusses methodological issues and challenges encountered in a mixed-methods research project on asylum seekers in Bavaria, Germany. It documents the research design of, and field experiences in, a quantitative survey based on a quota sampling procedure and a qualitative study, both of which were conducted in collective accommodation for asylum seekers at selected locations in that federal state. Standardized PAPI multiple-topic questionnaires were completed by asylum seekers from Syria, Afghanistan, Eritrea, and Iraq (N = 779); most of the questionnaires were self-administered. In addition, 12 qualitative face-to-face biographical interviews were conducted in order to gain an in-depth understanding of attitudes and experiences of asylum seekers. This report focuses on the following aspects: the use of gatekeepers to facilitate participant recruitment; sampling procedures; the involvement of interpreters in the data collection process; response bias and response behaviors among asylum seekers; and the experiences gained from data collection in collective accommodation for asylum seekers. KW - asylum seekers in Germany KW - biographical research KW - gatekeeper approach KW - methodological issues KW - mixed methods KW - surveys KW - use of interpreters Y1 - 2019 U6 - https://doi.org/10.12758/mda.2019.02 N1 - Corresponding author: Sonja Haug VL - 13 IS - 2 SP - 321 EP - 340 PB - GESIS – Leibniz-Institut für Sozialwissenschaften ER - TY - JOUR A1 - Snarskii, Andrei A. A1 - Kalita, Viktor M. A1 - Shamonin (Chamonine), Mikhail T1 - Renormalization of the critical exponent for the shear modulus of magnetoactive elastomers JF - Scientific Reports N2 - It is shown that the critical exponent for the effective shear modulus of a composite medium where a compliant polymer matrix is filled with ferromagnetic particles may significantly depend on the external magnetic field. The physical consequence of this dependence is the critical behavior of the relative magnetorheological effect. Y1 - 2018 U6 - https://doi.org/10.1038/s41598-018-22333-6 N1 - Corresponding author: Mikhail Shamonin VL - 8 SP - 1 EP - 8 PB - Nature ER - TY - JOUR A1 - Linner, Thomas ED - Linner, Thomas T1 - Special issue ISARC 2021 JF - Construction Robotics N2 - The research filed of construction robotics broadens increasingly in terms of complexity, approaches, technologies used, active stakeholders, and application areas. Worldwide labour and resource shortages, the need to increase circularity and resource efficiency, new materials and the increasing utilisation of digital construction tools in the planning and construction industry massively spur the uptake of robotic solutions for on-site construction. The initial boom of construction robots happened in the 1970s, driven by the Japanese construction industry. In the 1980s, a combination with parallel developments was supposed to achieve complete, integrated robotic on-site factories. From the mid-1980s onwards, the global interest in construction robots decreased gradually. Bulky and expensive systems, complex on-site navigation and logistics approaches, a narrow scope of tasks, inflexibility, incompatibility with on-site work organisation and professional qualification, low usability and insufficient inter-robot coordination capabilities revealed the immaturity of the systems. Only a few organisations predominantly situated in Asia such as Takenaka, Obayashi, Kajima Corporation, Nihon Bisho Co., Samsung, and Hitachi maintained development activities. However, since the mid-2010s, development activities are gaining traction again. On the application side, this is mainly driven by trends such as the need to upgrade the energy performance of buildings in Europe, a global necessity to remove asbestos from existing structures, and a demand for enormous quantities of high-rise buildings all over East Asia. On the system side, the renewed interest stems from major advances in physical–mechanical robot technology in other automation-driven industries such as the automotive industry. Robots became lighter, more flexible, their parts modular and interchangeable, more user friendly as well as significantly cheaper. On the digital side, the BIM-to-Robot pipeline was subject of intensive reserach and development. More and more methods and tools help to increase the usability of robots and facilitate the simulation and optimisation of robot-driven construction processes. In the last 4–5 years, the worldwide growing need and interest in construction robotics became highly evident. More than 200 robot systems are pushed by start-ups and spin-offs and their investors to the market. This is backed by an enormous number of activities and projects carried out in the academic area pushing to the boundaries of what is technologically possible. Major associations and their conferences increase significantly in popularity such as ISARC (International Association for Automation and Robotics in Construction), EC3 (European Council of Computing in Construction), and Robots in Architecture. Competency in digital construction, automation and robotics becomes a key for all stakeholders in the construction industry and many universities worldwide launch dedicated interdisciplinary programs. Powerful governments (China) and major funding programs such as Horizon Europe (Europe) massively request and fund the development of robotic solutions for construction such as drones, mobile robots, 3D-printing solutions, cable-driven robots, and exoskeletons. Regulators and standardisation organisation start to develop the first certification and standardisation schemes for construction robots and large software companies make attempts to allow to simulate and program robotic construction processes efficiently and robustly based on digital building and construction data. To showcase the diversity of cutting-edge research in the area, this special issue invited eight extended versions of selected papers from the ISARC 2021 conference. As such, this issue covers digital approaches to embed fabrication and robot information in BIM and IFC and program robots directly from digital building models. New robot systems spur novel robotic production processes, and machine learning enable novel logistics approaches for building components that may ultimately lead to robotic cranes and other robotic on-site logistics and handling solutions (including autonomous construction machines). In parallel, systematic evaluation and robot development methods are developed that allow to shed light on their performance in the construction process. Y1 - 2022 U6 - https://doi.org/10.1007/s41693-022-00079-y N1 - Corresponding author: Thomas Linner VL - Vol. 6 IS - Issue 2 SP - 58 EP - 68 PB - Springer Nature ER - TY - CHAP A1 - Suess, Franz A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Towards ergonomics working - machine learning algorithms and musculoskeletal modeling T2 - IOP Conference Series: Materials Science and Engineering N2 - Ergonomic workplaces lead to fewer work-related musculoskeletal disorders and thus fewer sick days. There are various guidelines to help avoid harmful situations. However, these recommendations are often rather crude and often neglect the complex interaction of biomechanical loading and psychological stress. This study investigates whether machine learning algorithms can be used to predict mechanical and stress-related muscle activity for a standardized motion. For this purpose, experimental data were collected for trunk movement with and without additional psychological stress. Two different algorithms (XGBoost and TensorFlow) were used to model the experimental data. XGBoost in particular predicted the results very well. By combining it with musculoskeletal models, the method shown here can be used for workplace analysis but also for the development of real-time feedback systems in real workplace environments. Y1 - 2021 U6 - https://doi.org/10.1088/1757-899X/1208/1/012001 SN - 1757-899X N1 - Corresponding author: Sebastian Dendorfer VL - 1208 PB - IOP Publishing ER - TY - JOUR A1 - Linner, Thomas T1 - Special issue: Implementation-Oriented Construction Robotics JF - Construction Robotics Y1 - 2023 U6 - https://doi.org/10.1007/s41693-023-00100-y N1 - Corresponding author: Thomas LInner VL - 7 SP - 1 EP - 2 PB - Springer Nature ER - TY - JOUR A1 - Mikhaeil, Makram A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - Experimental Investigation of the Adsorption and Desorption Kinetics on an Open-Structured Asymmetric Plate Heat Exchanger; Matching Between Small-Scale and Full-Scale Results JF - Frontiers in Energy Research N2 - This paper introduces the results of an experimental study on the adsorption and desorption kinetics of a commercially available, open-structured asymmetric plate heat exchanger adapted to act as an adsorber/desorber for the application in adsorption heat transformation processes. In addition, a volumetric large temperature jump (V-LTJ) kinetic setup was applied to measure the adsorption and desorption kinetics of a small-scale adsorbent sample prepared dedicatedly to be representative for the adsorbent domain inside the investigated adsorber plate heat exchanger (APHE). All kinetic results of the small-scale adsorbent sample and the APHE were fitted into exponential forms with a single characteristic time constant (τ) with a coefficient of determination (R2) better than 0.9531. A very good matching between the small-scale and full-scale adsorption kinetic measurements was obtained, with an average relative deviation of 12.3% in the obtained τ-values. In addition, the kinetic data of the small-scale adsorbent sample were utilized for estimating the expected specific instantaneous and moving average powers of the evaporator/condenser heat exchanger. The average relative deviation (ARD) between the moving average specific evaporator powers obtained from the small-scale and the full-scale measurements amounts between 5.4 and 15.1%. Y1 - 2022 U6 - https://doi.org/10.3389/fenrg.2022.818486 N1 - Corresponding author: Belal Dawoud VL - 10 SP - 1 EP - 15 PB - Frontiers ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Diermeier, Andreas A1 - Szecsey, Tamara T1 - Dielectric behaviour of magnetic hybrid materials JF - Physical Sciences Reviews N2 - The objectives of this work include the analysis of electrical and magnetic properties of magneto-elastic hybrid materials with the intention of developing new techniques for sensor and actuator applications. This includes the investigation of dielectric properties at both low and high frequencies. The behaviour of capacitors whose dielectrics comprise magnetic hybrid materials is well known. Such interfacial magnetocapacitance can be varied according to magnetic content, magnetic flux density and the relative permittivity of the polymer matrix together with other dielectric content. The basic function of trapping electrical charges in polymers (electrets) is also established technology. However, the combination of magnetoactive polymers and electrets has led to the first electromagnetic device capable of adhering to almost any material, whether magnetically susceptible or not. During the course of this research, in addition to dielectrics, electrically conductive polymers based on (PDMS) matrices were developed in order to vary the electrical properties of the material in a targeted manner. In order to ensure repeatable results, this demanded new fabrication techniques hitherto unavailable. The 3D printing of silicones is far from being a mature technology and much pioneering work was necessary before extending the usual 3 d.o.f. to include orientation about and diffusion of particles in these three axes, thus leading to the concept of 6D printing. In 6D printing, the application of a magnetic field can be used during the curing process to control the particulate distribution and thus the spatial filler particle density as desired. Most of the devices (sensors and actuators) produced by such methods contain levels of carbonyl iron powder (CIP) embedded magnetic filler of up to 70 wt%. Contrary to this, a hitherto neglected research area, namely magnetoactive polymers (MAPs) having significantly lower magnetic particle concentrations (1 to 3 wt% CIP) were also investigated. With filler concentrations lower than 3 wt%, structures are formed which are completely absent at higher filler levels. CIP concentrations in the range of 1wt% demonstrate the formation of toroidal structures. Further development of coherent rings with a compact order results as filler concentrations increase towards 2 wt%. Above 3 wt% the structure eventually disintegrates to the usual random order found in traditional MAP with higher CIP content. Structured samples containing 1%–3 wt% CIP were investigated with the aid of X-ray tomography where solitary ring structures can be observed and eventually the formation of capillary doubles. Over wavelengths ranging from 1 to 25 µm, spectroscopic analysis of thin film MAP samples containing 2 wt% CIP revealed measurable magnetic-field-dependent changes in IR absorption at a wavenumber 2350 (λ = 4.255 µm). This was found to be due to the diamagnetic susceptibility of atmospheric carbon dioxide (CO2). Consequently, the first potential application for sparse matrix MAPs was found. KW - cappillary doublet KW - diamagnetic KW - elastomer dielectric KW - FTIR KW - interfacial magnetocapacitance KW - magnetoactive polymer KW - PDMS KW - toroid Y1 - 2021 U6 - https://doi.org/10.1515/psr-2019-0121 N1 - Corresponding author: Gareth J. Monkman VL - 7 IS - 10 SP - 1169 EP - 1185 PB - de Gruyter ER - TY - JOUR A1 - Hillebrand, Patrick A1 - Westner, Markus T1 - Success factors of long-term CIOs JF - Information Systems and e-Business Management N2 - Although the average tenure of CIOs has increased over the last years, the majority of CIOs have been in their positions for only three years or less. Nevertheless, some CIOs have been successful in their position for a long time. In this study, we use tenure as a proxy for success as a CIO. The goal of this paper is to examine factors that are critical to the success of long-term CIOs. For this purpose, we created and analyzed resumes of 384 CIOs. Out of these 384, we conducted 19 interviews with CIOs from top-tier companies and collected and analyzed both qualitative and quantitative data. In the process, we were able to identify nine factors that are critical for the success (CSF) of CIOs. These factors fall into three categories. Category “Personality” includes “Accepting and embracing change” (CSF #1), “Being perseverant to pursue long-term goals” (CSF #2), “Anticipating the future through visionary thinking” (CSF #3), and “Being empathetic to deal with uncertainty felt by co-workers” (CSF #4). The “Role Fulfilment” category includes “Cross-functional involvement and integration of the IT organization” (CSF #5), “Positioning and restructuring of the IT organization” (CSF #6), and “Well-connected and communicative leadership” (CSF #7). The “Organizational Environment” category consists of “Availability of skilled workforce” (CSF #8) and “Reporting line to the CEO” (CSF #9). CSFs 1, 2, and 3 were perceived as most important by the participating CIOs. The results may be of particular interest both to aspiring CIOs and equally their employing organizations, as they reflect what long-term CIOs value during their time in office. KW - Chief information officer KW - CIO tenure KW - Critical success factors KW - CIO roles KW - Interview-based exploratory mixed-method study Y1 - 2022 U6 - https://doi.org/10.1007/s10257-021-00546-z N1 - Corresponding Author: Markus Westner VL - 20 SP - 79 EP - 122 PB - Springer Nature ER - TY - JOUR A1 - Schoenenwald, Alexander A1 - Kern, Simon A1 - Viehhauser, Josef A1 - Schildgen, Johannes T1 - Collecting and visualizing data lineage of Spark jobs JF - Datenbank-Spektrum N2 - Metadata management constitutes a key prerequisite for enterprises as they engage in data analytics and governance. Today, however, the context of data is often only manually documented by subject matter experts, and lacks completeness and reliability due to the complex nature of data pipelines. Thus, collecting data lineage—describing the origin, structure, and dependencies of data—in an automated fashion increases quality of provided metadata and reduces manual effort, making it critical for the development and operation of data pipelines. In our practice report, we propose an end-to-end solution that digests lineage via (Py‑)Spark execution plans. We build upon the open-source component Spline, allowing us to reliably consume lineage metadata and identify interdependencies. We map the digested data into an expandable data model, enabling us to extract graph structures for both coarse- and fine-grained data lineage. Lastly, our solution visualizes the extracted data lineage via a modern web app, and integrates with BMW Group’s soon-to-be open-sourced Cloud Data Hub. Y1 - 2021 U6 - https://doi.org/10.1007/s13222-021-00387-7 N1 - Corresponding author: Johannes Schildgen VL - 21 IS - 3 SP - 179 EP - 189 PB - Springer Nature ER - TY - JOUR A1 - Curbach, Janina A1 - Lander, Jonas A1 - Dierks, Marie-Luise A1 - Grepmeier, Eva-Maria A1 - von Sommoggy, Julia T1 - How do health professionals translate evidence on early childhood allergy prevention into health literacy-responsive practice? BT - A protocol for a mixed-method study on the views of German health professionals JF - BMJ OPEN N2 - Introduction Paediatricians, general practitioners (GPs) and midwives in primary care are important sources of information for parents on early childhood allergy prevention (ECAP). Research has shown that preventive counselling by health professionals can be effective in improving patients' health literacy (HL) and health behaviour. Providing effective advice relies on two factors. First, health professionals need be up-to-date with research evidence on ECAP, to consider popular misconceptions and fears and to translate this knowledge into clear recommendations for parents (knowledge translation). Second, they need to know and apply counselling techniques and create a practice setting which accommodates parental HL needs (health literacy-responsive care). The objective of this study is to explore and assess how German health professionals take up and translate ECAP evidence into appropriate recommendations for parents, how they consider HL in counselling and practice organisation and what barriers and enablers they find in their performance of HL-responsive ECAP. Methods and analysis The study has a sequential mixed-method design, in two phases. In the first phase, qualitative semi-structured expert interviews will be conducted with health professionals (paediatricians, GPs and midwives) at primary care level and professional policy level. Data collection is ongoing until January 2022. In the second phase, based on the qualitative results, a standardised questionnaire will be developed, and pilot-tested in a wider population of German health professionals. The findings of both phases will be integrated. Ethics and dissemination The study has received ethical approval from the Ethics Committee of the University of Regensburg (18-1205-101). The results will be published in international peer-reviewed open access journals and via presentations at scientific conferences. The results will also be shared with German health professionals, decision-makers and potential funders of interventions. KW - FOOD ALLERGY KW - INTERVENTION KW - MINDLINES KW - PERCEPTIONS KW - PERSPECTIVES KW - PHYSICAL-ACTIVITY KW - preventive medicine KW - PRIMARY-CARE KW - public health KW - qualitative research KW - social medicine Y1 - 2021 U6 - https://doi.org/10.1136/bmjopen-2020-047733 N1 - Corresponding author: Janina Curbach VL - 11 SP - 1 EP - 8 PB - BMJ ER - TY - JOUR A1 - Berndt, Dominik A1 - Muggli, Josef A1 - Heckel, Robert A1 - Rahiman, Mohd Fuad A1 - Lindner, Matthias A1 - Heinrich, Stephan A1 - Plöchinger, Heinz A1 - Schreiner, Rupert T1 - A Robust Miniaturized Gas Sensor for H₂ and CO₂ Detection Based on the 3ω Method JF - Sensors N2 - Gas concentration monitoring is essential in industrial or life science areas in order to address safety-relevant or process-related questions. Many of the sensors used in this context are based on the principle of thermal conductivity. The 3ω-method is a very accurate method to determine the thermal properties of materials. It has its origin in the thermal characterization of thin solid films. To date, there have been very few scientific investigations using this method to determine the thermal properties of gases and to apply it to gas measurement technology. In this article, we use two exemplary gases (H2 and CO2) for a systematical investigation of this method in the context of gas analysis. To perform our experiments, we use a robust, reliable sensing element that is already well established in vacuum measurement technology. This helix-shaped thin wire of tungsten exhibits high robustness against chemical and mechanical influences. Our setup features a compact measurement environment, where sensor operation and data acquisition are integrated into a single device. The experimental results show a good agreement with a simplified analytical model and FEM simulations. The sensor exhibits a lower detection limit of 0.62% in the case of CO2, and only 0.062% in case the of H2 at an excitation frequency of 1 Hz. This is one of the lowest values reported in literature for thermal conductivity H2 sensors. KW - 3ω-method KW - CO2 sensor KW - H2 sensor KW - thermal gas sensor Y1 - 2022 U6 - https://doi.org/10.3390/s22020485 N1 - Corresponding author: Dominik J. Berndt VL - 22 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Steininger, Peter A1 - Gaderer, Matthias A1 - Steffens, Oliver A1 - Dawoud, Belal T1 - Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System JF - Buildings N2 - A newly-developed solar active thermal insulation system (SATIS) is introduced with the main objective to accomplish a highly-dependent total solar transmittance on the irradiation angle. SATIS is also designed to obtain the maximum transmittance at a prescribed design irradiation angle and to reduce it remarkably at higher irradiation angles. A purely mineral thermal insulation plaster with micro hollow glass spheres is applied to manufacture the investigated SATIS prototype. Light-conducting elements (LCEs) have been introduced into SATIS and suitable closing elements have been applied. The SATIS prototype has been investigated both experimentally and numerically. It turned out that the contributions of conduction, radiation and convection to the effective thermal conductivity of SATIS, without the closing elements (49 mWmK), amount to 86.2%, 13.2% and 0.6%, respectively. The angle-dependent short-wave radiation exchange within the LCE has been investigated via ray tracing. At the incidence angle of 19% (design angle), 27% of the radiation within the LCE is absorbed by the absorber plate, resulting in measured and computed total solar energy transmittances of 11.2%/11.7%, respectively. For a typical summer irradiation angle of 60%, 98% of the incident radiation is absorbed by the surfaces at the entrance of the LCE. The corresponding total solar energy transmittance amounts to 2.9%. KW - angle-dependent total solar energy transmittance KW - effective thermal conductivity KW - experimental investigation KW - numerical simulation KW - ray tracing KW - solar active thermal insulation system (SATIS) Y1 - 2021 U6 - https://doi.org/10.3390/buildings11030123 N1 - Corresponding author: Belal Dawoud VL - 11 IS - 3 SP - 1 EP - 22 PB - MDPI ER - TY - JOUR A1 - Gamisch, Bernd A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions JF - Applied Sciences N2 - This work aims at investigating the reduction/oxidation (redox) reaction kinetics on iron oxide pellets under different operating conditions of thermochemical hydrogen storage. In order to reduce the iron oxide pellets (90% Fe2O3, 10% stabilizing cement), hydrogen (H2) is applied in different concentrations with nitrogen (N2), as a carrier gas, at temperatures between between 700 ∘C and 900 ∘C, thus simulating the charging phase. The discharge phase is triggered by the flow of a mixture out of steam (H2O) and N2 at different concentrations in the same temperature range, resulting in the oxidizing of the previously reduced pellets. All investigations were carried out in a thermo-gravimetric analyzer (TGA) with a flow rate of 250mL/min. To describe the obtained kinetic results, a simplified analytical model, based on the linear driving force model, was developed. The investigated iron oxide pellets showed a stable redox performance of 23.8% weight reduction/gain, which corresponds to a volumetric storage density of 2.8kWh/(L bulk), also after the 29 performed redox cycles. Recalling that there is no H2 stored during the storage phase but iron, the introduced hydrogen storage technology is deemed very promising for applications in urban areas as day-night or seasonal storage for green hydrogen. KW - hydrogen storage KW - iron/iron oxide KW - reaction kinetics KW - redox reactions Y1 - 2021 U6 - https://doi.org/10.3390/app11041623 N1 - Corresponding author: Belal Dawoud VL - 11 IS - 4 SP - 1 EP - 15 PB - MDPI CY - Basel ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Mini-Extruder for 3D Magnetoactive Polymer Printing JF - Advances in Materials Science and Engineering N2 - This work describes the development of a new miniature extruder, essential to cavity-free 3D printing of silicone-based smart materials. This makes the 3D printing of magnetoactive and electroactive polymer soft robotic components and devices directly from CAD data possible. The special feature of such an extruder is that it is designed for use with addition-crosslinking RTV-2 silicones, including solid particulate additives. The extruder merges the respective components automatically during extrusion which obviates the need for premixing and vacuum evacuation. Problems associated with inhomogeneities and unwanted cavity production are consequently eliminated. Rheological details necessary to the design, together with some preliminary performance results, are presented. Y1 - 2019 U6 - https://doi.org/10.1155/2019/8715718 N1 - Corresponding author: Gareth J. Monkman SP - 1 EP - 8 PB - HINDAWI ER - TY - JOUR A1 - Stein, Oliver T1 - On analytic properties of the standard zeta function attached to a vector-valued modular form JF - Research in Number Theory N2 - We proof a Garrett–Böcherer decomposition of a vector-valued Siegel Eisenstein series E2l,0 of genus 2 transforming with the Weil representation of Sp2(Z) on the group ring C[(L′/L)2]. We show that the standard zeta function associated to a vector-valued common eigenform f for the Weil representation can be meromorphically continued to the whole s-plane and that it satisfies a functional equation. The proof is based on an integral representation of this zeta function in terms of f and E2l,0. Y1 - 2022 U6 - https://doi.org/10.1007/s40993-022-00368-z N1 - Corresponding author: Oliver Stein VL - 8 IS - 4 SP - 1 EP - 27 PB - Springer Nature ER - TY - JOUR A1 - Dechant, Eduard A1 - Fedulov, Feodor A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail T1 - Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting JF - Applied Science N2 - Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs). The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power. KW - array KW - BAND-PASS FILTERS KW - bandwidth KW - BIMORPH KW - Optimization KW - OUTPUT KW - PERFORMANCE KW - piezoelectric cantilever KW - POWER KW - vibration energy harvesting Y1 - 2017 U6 - https://doi.org/10.3390/app7121324 N1 - Corresponding Author: Mikhail Shamonin VL - 7 IS - 12 PB - MDPI ER - TY - JOUR A1 - Frikel, Jürgen A1 - Haltmeier, Markus T1 - Efficient regularization with wavelet sparsity constraints in photoacoustic tomography JF - Inverse Problems N2 - In this paper, we consider the reconstruction problem of photoacoustic tomography (PAT) with a flat observation surface. We develop a direct reconstruction method that employs regularization with wavelet sparsity constraints. To that end, we derive a wavelet-vaguelette decomposition (WVD) for the PAT forward operator and a corresponding explicit reconstruction formula in the case of exact data. In the case of noisy data, we combine the WVD reconstruction formula with soft-thresholding, which yields a spatially adaptive estimation method. We demonstrate that our method is statistically optimal for white random noise if the unknown function is assumed to lie in any Besov-ball. We present generalizations of this approach and, in particular, we discuss the combination of PAT-vaguelette soft-thresholding with a total variation (TV) prior. We also provide an efficient implementation of the PAT-vaguelette transform that leads to fast image reconstruction algorithms supported by numerical results. KW - Image reconstruction KW - photoacoustic tomography KW - sparsity constraints KW - variational regularization KW - wavelet-vaguelette decomposition Y1 - 2018 U6 - https://doi.org/10.1088/1361-6420/aaa0ac N1 - Corresponding authors: Jürgen Frikel and Markus Haltmeier VL - 34 IS - 2 SP - 1 EP - 28 ER - TY - JOUR A1 - Diamantidis, Dimitris T1 - A Critical View on Environmental and Human Risk Acceptance Criteria JF - International Journal of Environmental Science and Development N2 - Natural and technological hazards have a major impact on environmental and human safety. Risk assessment plays an essential role in the risk management of the effects of such hazards. This contribution summarizes first the general formulation of risk depending on two parameters: hazard probability and associated consequences. Problems faced in industrial applications based on the experience of the author are discussed. Risk acceptance criteria for the contributors to risk i.e. human, economic and environment are critically reviewed. Resilience based criteria are also included and conclusions for future developments are provided. KW - Environmental risk KW - human risk KW - Risk acceptance KW - Risk analysis KW - safety measures Y1 - 2017 U6 - https://doi.org/10.18178/ijesd.2017.8.1.921 N1 - Corresponding author: Dimitris Diamantidis VL - 8 IS - 1 SP - 62 EP - 66 ER - TY - JOUR A1 - Franz, Maja A1 - Wolf, Lucas A1 - Periyasamy, Maniraman A1 - Ufrecht, Christian A1 - Scherer, Daniel D. A1 - Plinge, Axel A1 - Mutschler, Christopher A1 - Mauerer, Wolfgang T1 - Uncovering Instabilities in Variational-Quantum Deep Q-Networks JF - Journal of the Franklin Institute N2 - Deep Reinforcement Learning (RL) has considerably advanced over the past decade. At the same time, state-of-the-art RL algorithms require a large computational budget in terms of training time to converge. Recent work has started to approach this problem through the lens of quantum computing, which promises theoretical speed-ups for several traditionally hard tasks. In this work, we examine a class of hybrid quantumclassical RL algorithms that we collectively refer to as variational quantum deep Q-networks (VQ-DQN). We show that VQ-DQN approaches are subject to instabilities that cause the learned policy to diverge, study the extent to which this afflicts reproduciblity of established results based on classical simulation, and perform systematic experiments to identify potential explanations for the observed instabilities. Additionally, and in contrast to most existing work on quantum reinforcement learning, we execute RL algorithms on an actual quantum processing unit (an IBM Quantum Device) and investigate differences in behaviour between simulated and physical quantum systems that suffer from implementation deficiencies. Our experiments show that, contrary to opposite claims in the literature, it cannot be conclusively decided if known quantum approaches, even if simulated without physical imperfections, can provide an advantage as compared to classical approaches. Finally, we provide a robust, universal and well-tested implementation of VQ-DQN as a reproducible testbed for future experiments. KW - Artificial Intelligence KW - Computer Science KW - Quantum Physics Y1 - 2022 U6 - https://doi.org/10.1016/j.jfranklin.2022.08.021 SN - 0016-0032 N1 - Corresponding author: Maja Franz PB - Elsevier ET - In Press, Corrected Proof ER - TY - JOUR A1 - Schloplocher, Paul Dragos A1 - Ettengruber, Stefan A1 - Steffens, Oliver T1 - Improvements for building-performance simulations by a comparative finite-element method analysis JF - Energy and Buildings N2 - This paper presents a method to improve building-performance simulations (BPS) by the comparison and analysis of different approaches based on finite-element method (FEM) models. The lumped parameter method (LPM) is used in several BPS programs and tools. It has the advantage of fast computing times and comparably good accuracy for thermal and energy loads. With the help of detailed FEM simulations, it is possible to further improve the degree of detail and accuracy while maintaining the high simulation speed. In this work, we compare time-dependent results for local temperatures in a generic reference room within a given periode of time. In a second step, the differences between the models with respect to various physical effects are analyzed and used to introduce additional equations into the LPM model in order to improve its accuracy. Thus, we discuss potentials for improvement for BPS and demonstrate a method of a practical implementation. The results show minor differences of less than 0.1 K for radiation and heat transfer, so their level of detail in BPS is appropriate. In these terms, no improvements were pursued within the work. However, the FEM simulation is capable of calculating the internal convective heat transfer and thermal bridges more accurately due to the use of computational fluid dynamics (CFD) and the geometrically precise representation of the FEM model. Here, deviations of up to 1 K in room temperature (convective heat transfer) and up to 0.5 K in wall temperatures (thermal bridges) were pointed out. By improving the LPM with equations obtained from the FEM, these deviations can be reduced to less than 0.2 K, which is a considerable improvement in accuracy. KW - Lumped parameter model KW - Finite-element method KW - Building performance simulation Y1 - 2023 U6 - https://doi.org/10.1016/j.enbuild.2022.112563 N1 - Corresponding author: Dragos Paul Schoplocher VL - 278 SP - 1 EP - 12 PB - Elsevier ER - TY - JOUR A1 - Maiwald, Frederik A1 - Roider, Clemens A1 - Schmidt, Michael A1 - Hierl, Stefan T1 - Optical Coherence Tomography for 3D Weld Seam Localization in Absorber-Free Laser Transmission Welding JF - Applied Sciences N2 - Quality and reliability are of the utmost importance for manufacturing in the optical and medical industries. Absorber-free laser transmission welding enables the precise joining of identical polymers without additives or adhesives and is well-suited to meet the demands of the aforementioned industries. To attain sufficient absorption of laser energy without absorbent additives, thulium fiber lasers, which emit in the polymers’ intrinsic absorption spectrum, are used. Focusing the laser beam with a high numerical aperture provides significant intensity gradients inside the workpiece and enables selective fusing of the internal joining zone without affecting the surface of the device. Because seam size and position are crucial, the high-quality requirements demand internal weld seam monitoring. In this work, we propose a novel method to determine weld seam location and size using optical coherence tomography. Changes in optical material properties because of melting and re-solidification during welding allow for weld seam differentiation from the injection-molded base material. Automatic processing of the optical coherence tomography data enables the identification and measurement of the weld seam geometry. The results from our technique are consistent with microscopic images of microtome sections and demonstrate that weld seam localization in polyamide 6 is possible with an accuracy better than a tenth of a millimeter. KW - image processing KW - laser transmission welding KW - optical coherence tomography KW - process monitoring KW - transparent polymers Y1 - 2022 U6 - https://doi.org/10.3390/app12052718 N1 - Corresponding author: Frederik Maiwald VL - 12 IS - 5 SP - 1 EP - 11 PB - MPDI CY - Basel ER - TY - JOUR A1 - Kreitmeier, Florian A1 - Chashin, Dmitri V. A1 - Fetisov, Yuri K. A1 - Fetisov, Leonid Y. A1 - Schulz, Irene A1 - Monkman, Gareth J. A1 - Shamonin (Chamonine), Mikhail T1 - Nonlinear Magnetoelectric Response of Planar Ferromagnetic-Piezoelectric Structures to Sub-Millisecond Magnetic Pulses JF - Sensors N2 - The magnetoelectric response of bi- and symmetric trilayer composite structures to pulsed magnetic fields is experimentally investigated in detail. The structures comprise layers of commercially available piezoelectric (lead zirconate titanate) and magnetostrictive (permendur or nickel) materials. The magnetic-field pulses have the form of a half-wave sine function with duration of 450 µs and amplitudes ranging from 500 Oe to 38 kOe. The time dependence of the resulting voltage is presented and explained by theoretical estimations. Appearance of voltage oscillations with frequencies much larger than the reciprocal pulse length is observed for sufficiently large amplitudes (~1-10 kOe) of the magnetic-field pulse. The origin of these oscillations is the excitation of bending and planar acoustic oscillations in the structures. Dependencies of the magnetoelectric voltage coefficient on the excitation frequency and the applied magnetic field are calculated by digital signal processing and compared with those obtained by the method of harmonic field modulation. The results are of interest for developing magnetoelectric sensors of pulsed magnetic fields as well as for rapid characterization of magnetoelectric composite structures. Y1 - 2012 U6 - https://doi.org/10.3390/s121114821 N1 - Corresponding author: Mikhail Shamonin VL - 12 IS - 11 SP - 14821 EP - 14837 PB - MDPI CY - Basel ER - TY - JOUR A1 - Apelsmeier, Andreas A1 - Gleixner, Ramona A1 - Mayer, Matthias A1 - Shamonin (Chamonine), Mikhail A1 - Schmauss, Bernhard T1 - Intensity referencing in an extrinsic optical fiber temperature sensor JF - Procedia Engineering N2 - Optical fiber sensors based on intensity measurement require some form of intensity referencing to avoid errors arising from parasitic losses. Known techniques of referencing such as balanced bridge, divided beam systems or two-wavelength referencing are not suitable for low-cost applications since they use relatively complicated optical components such as multiple LED sources, couplers, filters etc. In this work a novel method of referencing in an extrinsic optical fiber sensor system utilizing temperature dependence of absorption edge in a semiconductor crystal is described. The sensor system comprises a single LED source and no optical fiber junctions. The emission spectrum of an LED depends on its temperature. The reference is provided by controlling the temperature of an LED source and transmission measurements with different emission spectra. The entire process is controlled by a microprocessor unit. Performance of a sensor system is investigated and it is shown that the losses in connectors may be compensated for. KW - Extrinsic optical fiber sensor KW - Intensity referencing KW - Temperature measurement KW - Absorption edge KW - Semiconductor KW - Hot-spot measurement Y1 - 2010 U6 - https://doi.org/10.1016/j.proeng.2010.09.301 VL - 5 SP - 1095 EP - 1098 PB - Elsevier ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Szecsey, Tamara T1 - Smart Stiction JF - Robotics & Automation Engineering Journal N2 - Soft robotics could loosely be described as the engineering science of expanded dexterity through controllable flexibility. The exploitation of controllable compliance through the judicious choice of soft flexible members, as opposed to a finite number of rigid kinematic joints, can result in greater dexterity without compromising simplicity. One example is the replacement of segmented mechanical legs with simple compliant material eruciform prolegs. To achieve this in robotics, without introducing additional mechanical joints, mobile surfaces with switchable coefficients of friction is essential. This paper explains how, using silicone based smart materials, the rapid alternation between kinematic and static friction (stiction) may be achieved. Y1 - 2019 U6 - https://doi.org/10.19080/RAEJ.2019.04.555641 N1 - Corresponding author: Gareth J. Monkman VL - 4 IS - 4 PB - Juniper Publishers ER - TY - JOUR A1 - Herrmann, Frank T1 - Human Experience Versus Rule Decision at Krones AG JF - Biomedical Journal of Scientific & Technical Research N2 - Final assembly at Krones AG must make the best possible use of its production space and meeting the specified customer due dates is critical. Via a self developed simulation tool, the present scheduling procedure is compared with the one by priority rule shortest slack. As a consequence slack should have a higher importance in the planning KW - Simulation of Scheduling KW - Tardiness KW - Unused Area Y1 - 2022 UR - https://biomedres.us/pdfs/BJSTR.MS.ID.006691.pdf U6 - https://doi.org/10.26717/BJSTR.2022.42.006691 SN - 2574 -1241 N1 - Corressponding author: Frank Herrmann VL - 42 IS - 1 SP - 33255 EP - 33260 PB - Biomedical Research Network+ ER - TY - JOUR A1 - Göppel, Simon A1 - Frikel, Jürgen A1 - Haltmeier, Markus T1 - Data-Proximal Complementary ℓ1-TV Reconstruction for Limited Data Computed Tomography JF - Mathematics N2 - In a number of tomographic applications, data cannot be fully acquired, resulting in severely underdetermined image reconstruction. Conventional methods in such cases lead to reconstructions with significant artifacts. To overcome these artifacts, regularization methods are applied that incorporate additional information. An important example is TV reconstruction, which is known to be efficient in compensating for missing data and reducing reconstruction artifacts. On the other hand, tomographic data are also contaminated by noise, which poses an additional challenge. The use of a single regularizer must therefore account for both the missing data and the noise. A particular regularizer may not be ideal for both tasks. For example, the TV regularizer is a poor choice for noise reduction over multiple scales, in which case ℓ1 curvelet regularization methods are well suited. To address this issue, in this paper, we present a novel variational regularization framework that combines the advantages of different regularizers. The basic idea of our framework is to perform reconstruction in two stages. The first stage is mainly aimed at accurate reconstruction in the presence of noise, and the second stage is aimed at artifact reduction. Both reconstruction stages are connected by a data proximity condition. The proposed method is implemented and tested for limited-view CT using a combined curvelet–TV approach. We define and implement a curvelet transform adapted to the limited-view problem and illustrate the advantages of our approach in numerical experiments. KW - image reconstruction KW - limited data KW - artifact reduction KW - sparse regularization KW - total variation KW - wedge-adapted curvelets Y1 - 2024 U6 - https://doi.org/10.3390/math12101606 SN - 2227-7390 N1 - Corresponding author der OTH Regensburg: Jürgen Frikel (und Markus Haltmeier) VL - 12 IS - 10 PB - MDPI ER - TY - JOUR A1 - Mikhaeil, Makram A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - On the development of an innovative adsorber plate heat exchanger for adsorption heat transformation processes; an experimental and numerical study JF - Energy N2 - An innovative adsorber plate heat exchanger (APHE), which is developed for application in adsorption heat pumps, chillers and thermal energy storage systems, is introduced. A test frame has been constructed as a representative segment of the introduced APHE for applying loose grains of AQSOA-Z02. Adsorption kinetic measurements have been carried out in a volumetric large-temperature-jump setup under typical operating conditions of adsorption processes. A transient 2-D model is developed for the tested sample inside the setup. The measured temporal uptake variations with time have been fed to the model, through which a micro-pore diffusion coefficient at infinite temperature of 2 E−4 [m2s−1] and an activation energy of 42.1 [kJ mol−1] have been estimated. A 3-D model is developed to simulate the combined heat and mass transfer inside the APHE and implemented in a commercial software. Comparing the obtained results with the literature values for an extruded aluminium adsorber heat exchanger coated with a 500 μm layer of the same adsorbent, the differential water uptake obtained after 300 s of adsorption (8.2 g/100 g) implies a sound enhancement of 310%. This result proves the great potential of the introduced APHE to remarkably enhance the performance of adsorption heat transformation appliances. KW - Adsorber heat exchanger KW - Plate heat exchanger KW - Adsorption kinetics KW - Dynamic simulation Y1 - 2020 U6 - https://doi.org/10.1016/j.energy.2020.118272 N1 - Corresponding author: Belal Dawoud VL - 207 IS - September SP - 1 EP - 13 PB - Elsevier ER - TY - JOUR A1 - Huber, Lea A1 - Heindl, Melanie A1 - Schlosser, Marc A1 - Pfitzner, Arno A1 - Dawoud, Belal T1 - On the Cycle Stability and Macroscopic Structure of Iron Oxide Pellets for Thermochemical Hydrogen Storage: Influence of Water Content during the Pelletizing Process JF - Applied Sciences N2 - Hydrogen storage based on the repeated reduction and oxidation (redox) reactions of iron oxide/iron composites represents a promising technology. This work is dedicated to studying the influence of the amount of water added during the pelletizing process on the cycle stability and structure of iron oxide pellets. The storage composites were prepared from iron oxide (Fe2O3) and 10 wt.-% support material (cement) with different amounts of water (18 and 33 wt.-%) in a laboratory-scale pelletizing disk. To evaluate the cycle stability of the composites, the kinetics of the redox reactions were experimentally measured at 800 ∘ C in an atmosphere of 50% N2 and 50% H2 (reduction) or 50% steam (oxidation), respectively. Moreover, the structure of the pellets was analyzed by micro-computed tomography scans. It turned out that pellets with higher water contents attained faster kinetics and a higher cycle stability. The sample with the least water content (18 wt.-%) needed about 26 min and 19 min to reach a conversion rate of 80% during the reduction and oxidation reactions of the sixth redox cycle, respectively. In contrast, the sample with the highest water content (33 wt.-%) could achieve the same conversion rate after 18 min (reduction) and 13 min (oxidation) during the ninth redox cycle. KW - hydrogen storage KW - redox reactions KW - iron/iron oxide KW - pelletizing process KW - cycle stability KW - water content Y1 - 2023 U6 - https://doi.org/10.3390/app13116408 N1 - Corresponding author: Belal Dawoud VL - 13 IS - 11 PB - MDPI CY - 16 ER - TY - JOUR A1 - Schiek, Roland T1 - Nonlinear refractive index in silica glass JF - Optical Materials Expres N2 - The third-order nonlinear susceptibility of silica glass is measured via self-phase modulation in standard single mode fibers at a wavelength of 1550 nm. To minimize the influence of polarization state changes along the propagation only meter-long fibers were investigated. With pulse durations of picoseconds a quasi-instantaneous nonlinearity with ultrafast electronic and fast nuclear-vibration contributions produces under conditions of negligible dispersion a classic and clean nonlinear phase shift following exactly the shape of the pulse power. The complex pulse envelope was retrieved from frequency optical gating spectrograms. The nonlinear fiber parameter γ could be determined with an accuracy of 3.7 percent. Considering the mode field structure and the doping influence the nonlinear refractive index of silica glass as the fiber base material was found to be n 2 =2.22⋅10 −16 cm 2 W±6.0% for picosecond-long pulses. Comparing nonlinear phase shifts from linear and circular polarized light a nuclear-vibration contribution to the cubic fiber nonlinearity of 25 percent was estimated. Y1 - 2023 U6 - https://doi.org/10.1364/ome.489520 N1 - Corresponding author: Roland Schiek VL - 13 IS - 6 SP - 1727 EP - 1740 PB - Optica 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 - TY - JOUR A1 - Steininger, Peter A1 - Gaderer, Matthias A1 - Dawoud, Belal T1 - Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System JF - Sustainability N2 - A numerical parameter sensitivity analysis of the design parameters of the recently published solar selective thermal insulation system (SATIS) has been carried out to enhance its thermal and optical properties. It turned out that the insulation properties of SATIS can be effectively improved by reducing the length of the glass closure element. Increasing the area share of the light conducting elements (LCEs) and decreasing their length-to-diameter (L/D) ratio were identified as key parameters in order to increase the solar gain. Two SATIS variants were compared with the same wall insulation without SATIS in a yearly energetic performance assessment. The SATIS variant with 10 mm length of the closure element, 44.2% area share of LCE, as well as front and rear diameters of 12 mm/9 mm shows an 11.8% lower transmission heat loss over the heating period than the wall insulation without SATIS. A new methodology was developed to enable the implementation of the computed solar gains of SATIS in 1D simulation tools. The result is a radiant heat flow map for integration as a heat source in 1D simulation models. A comparison between the 1D and 3D models of the inside wall heat fluxes showed an integral yearly agreement of 98%. KW - effective thermal conductivity KW - parameter sensitivity analysis KW - radiant heat flow map KW - solar selective thermal insulation system (SATIS) KW - total solar energy transmittance KW - yearly energetic performance assessment Y1 - 2021 U6 - https://doi.org/10.3390/su13137336 N1 - Corresponding author: Belal Dawoud VL - 13 IS - 13 SP - 1 EP - 19 PB - MDPI CY - Basel ER - TY - JOUR A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Monkman, Gareth J. T1 - Structure formation in low concentration magnetoactive polymers JF - AIP advances N2 - This paper concerns recent research into the autonomous formation of micro-structures in low carbonyl iron powder (CIP) concentration magneto active polymers (MAP). Higher concentrations of CIP show an isotropic distribution of magnetic filler throughout the entire sample, while autonomous structure formation is possible at mass concentrations lower than 3%. The formation of micro-toroids commences as CIP concentration approaches 1% wt. Further development of coherent rings with a defined order follow as CIP concentrations increase toward 2% wt, whilst exceeding 3% wt leads to the same isotropic distribution found in higher concentration MAP. Structured samples containing between 1% wt and 3% wt CIP were investigated using X-Ray tomography where solitary structures could clearly be observed. The ring structures represent microinductivities whose geometries can be manipulated during fabrication. In addition, these structures are magnetic field sensitive. This is not only relevant to applications in the GHz and THz areas but recent research has revealed implications for optical, thermal, acoustic and even chemical MAP sensors. (C) 2019 Author(s). Y1 - 2019 U6 - https://doi.org/10.1063/1.5079997 N1 - Corresponding author: Dirk Sindersberger VL - 9 IS - 3 PB - AIP Publishing ER -