Recent Submissions
A method for boundary resources design to increase complementor satisfaction
(2025) Petrik, Dimitri; Mikusz, Martin
Boundary resources (BRs) designed to increase complementor satisfaction are essential for value co-creation in platform ecosystems, as complementors are not subject to the hierarchical control of a platform provider. Only satisfied complementors will engage in the development of innovative complementary solutions based on a platform. Ensuring this is no easy task for platform providers facing inter-platform competition, while existing research neglects complementor satisfaction as a target variable for platform providers to navigate the (re)design of BRs. To address this problem, the paper reports on an echeloned Design Science Research (DSR) project in the Industrial Internet of Things (IIoT) domain, which resulted in a method to align the (re)design of BRs with complementor satisfaction. Service quality techniques are used to obtain complementor feedback on the perceived quality of BRs, to assess issues and their impact on complementor satisfaction, and to prioritize measures that contribute most to complementor satisfaction, ultimately leading to increased complementor engagement. The method is theoretically grounded in the Expectation‐Confirmation Theory and draws on rich empirical data from the Siemens MindSphere ecosystem. It is instantiated as a prototype and evaluated in 12 focus groups. The method helps platform providers in the IIoT domain navigate the design of rich BR portfolios despite the dynamics of platform ecosystems in the IIoT, and advances research on platform governance.
Eyes in the clouds : spatial data analysis with gaze-enhanced point clouds
(2026) Geringer, Sergej; Balangé, Laura; Becher, Michael; Pathmanathan, Nelusa; Kerekes, Gabriel; Schwieger, Volker; Weiskopf, Daniel; Kurzhals, Kuno
Spatial data analysis is essential in domains such as construction, architecture, and geodesy, to check for differences between construction stages of a building. In this context, real-world environments are often digitally recorded as point clouds, providing a basis for digital processing and analysis. Furthermore, aspects of spatial cognition, often measured with eye tracking, are also relevant to many research questions related to how people perceive and understand space and spatial structures, e.g., in quality inspection of construction sites or buildings. We present a workflow to combine eye tracking and point cloud data to analyze user attention during inspection of spatial data in virtual environments. This type of data enrichment enables the deployment of established open-source software for cloud and mesh processing to analyze eye tracking data. Our workflow employs the investigation of point cloud data and simultaneous user gaze recording in virtual reality, followed by point-based gaze data analysis, interactive visualization, and authoring and production of high-quality dissemination materials for stakeholders. We showcase our approach with a usage scenario on how people investigate the construction of a pavilion building in virtual reality.
Untersuchung der Mensch-Maschine-Interaktion aktiver chirurgischer Assistenzsysteme für den Unterarm
(Stuttgart : Institut für Konstruktionstechnik und Technisches Design, 2026) Langer, Ferdinand Patrick; Maier, Thomas (Univ.-Prof. Dr.-Ing.)
Untersuchung der CO2-Konversion und Sauerstoffabtrennung in einem atmosphärischen Mikrowellenplasmabrenner
(2026) Wiegers, Katharina; Tovar, Günter E. M. (Prof. Dr.)
Die Plasmakonversion ist eine vielversprechende Technologie zur Aktivierung und Umwandlung stabiler Moleküle wie CO2 und N2. Diese Arbeit untersucht die Dissoziation von CO2 in CO und O2 in einem atmosphärischen Mikrowellenplasmabrenner. Zunächst werden die im Plasma vorhandenen Spezies mittels optischer Emissionsspektroskopie identifiziert. Anschließend wird die Zusammensetzung des Produktgases mit Massenspektrometrie und Fourier-Transformation-Infrarot-Absorptionsspektroskopie zur Bestimmung der Konversion und Energieeffizienz analysiert. Es zeigt sich, dass die Konversion von der Position im Abgaskanal abhängt, da das im Plasma zersetzte CO2 hinter der Plasmaflamme wieder zu CO2 rekombiniert. Um die Effizienz des Plasmaprozesses zu bewerten, muss das Produktgas im kalten und durchmischten Zustand gemessen werden. In der Standardkonfiguration befindet sich der Plasma-Membran-Reaktor zur Sauerstoffabtrennung auf der Resonatorstruktur. Es wird eine maximale Konversion von 9,9 % ± 1,5 % bei einem spezifischen Energieeintrag (SEI) von 1,4 eV · Molekül-1 bestimmt und eine maximale Energieeffizienz von 26,6 % ± 11,9 % bei einem SEI von 0,4 eV · Molekül-1.
Die CO2-Konversion wird durch die Rückreaktionen nach der Plasmazone bestimmt. Die Rückreaktionen können durch schnelles Abkühlen des Plasmagases, durch Sauerstoffentfernung oder durch die Zugabe eines Koreaktanten beeinflusst werden. In dieser Arbeit werden die ersten beiden Optionen untersucht. Als Erstes wird die Position des Kühlers variiert. Durch die Minimierung des Abstandes zwischen Kühler und Resonatorstruktur konnte die Konversion auf 18,5 % ± 1,5 % gesteigert werden. Zudem erhöhen Laval-Düsen mit unterschiedlichen Querschnittsverengungen die Konversion auf 28,9 % ± 1,5 % und die Energieeffizienz auf 36,4 % ± 5,4 %. Ein kleinerer Querschnittsdurchmesser führt zu einer effizienteren Abkühlung des Plasmagases. Eine Kühlerpositionsvariation in der Düsenkonfiguration verbessert ebenfalls die Konversion bei kleinen CO2-Flüssen.
Die Chemieindustrie benötigt für die Produktion von höherwertigen Kohlenwasserstoffen CO, das weniger als 1 % O2 enthält. Daher wird in dieser Arbeit eine integrierte Sauerstoffabtrennung im effluenten Plasma untersucht. Hierzu werden keramische, sauerstoffleitfähige Hohlfasermembranen, die aufgrund ihrer Geometrie eine große Oberfläche aufweisen, in den Plasma-Membran-Reaktor eingebracht. Es werden zwei Membranmaterialien verwendet. Das perowskitische La1-xCaxCo1-yFeyO3-δ (LCCF) ist bis zu 1220 °C im CO2-Plasma stabil und weist eine maximale O2-Permeation von 2,2 mL · min-1 auf. Das Zweiphasenmaterial Ce0,9Gd0,1O2-δ -Gd0,6Ce0,4Fe0,8Co0,2O3-δ ist bis 1400 °C im Plasma beständig und weißt eine maximale O2-Permeation von 1,0 mL · min-1 auf. In der Düsenkonfiguration tritt das effluente Plasmagas durch den divergenten Ausgang der Düse breitgefächert aus. Dadurch vergrößert sich die Interaktionsfläche zwischen effluentem Plasma und Membran und die Sauerstoffpermeation von LCCF wird auf 4,6 mL · min-1 gesteigert.
Tuning and optimal performance of an asymmetric vibro-impact nonlinear energy sink with dry friction
(2026) Youssef, Balkis; Leine, Remco I.
This paper presents a design-oriented framework for asymmetric vibro-impact nonlinear energy sinks (VI-NES) with dry friction. In this context, asymmetry arises from directional differences in friction and restitution properties. The proposed approach builds on analytical results from the Multiple Scales Method (MSM) and an impact map formulation developed to fully characterize near-resonant dynamics in symmetric frictional configurations. The absence of closed-form solutions for asymmetric systems motivates a pragmatic design hypothesis that bounds their response using symmetric reference systems. Based on this insight, a performance-driven design strategy is established, enabling efficient evaluation and optimization without exhaustive simulations. The cavity length, identified as the dominant tuning parameter, governs activation, dissipation efficiency, and regime transitions. Analytical, numerical, and experimental results confirm the predicted tunability of the asymmetric VI-NES through geometric adjustment and demonstrate the robustness and applicability of the proposed strategy for passive vibration mitigation in realistic mechanical systems.
Human health and ecological risk assessment of heavy metal contamination in the Tigris River (Mosul, Iraq) : a spatial-temporal analysis using CCME-WQI and HPI
(2026) Altahaan, Zena; Dobslaw, Daniel
River water quality assessments are commonly conducted under conventional anthropogenic pressures; however, the long-term environmental impacts of armed conflicts remain insufficiently understood. This study addresses this gap by evaluating the persistence of war-related heavy metal contamination and its associated human health risks in the Tigris River, Mosul, a post-conflict urban system. The results revealed that Cd, Pb, Cr, and Ni concentrations exceeded WHO guideline values across most sites, while Zn remained within acceptable limits. The highest contamination levels were observed in the central urban zone (Zone 3), which was directly affected by military activities. Hazard quotient (HQ) values for Cd and Pb exceeded the safe threshold (HQ > 1) at all sites, identifying them as dominant contributors to toxicity. The cumulative hazard index (HI) reached extremely high levels (>300 in 2022 and >200 in 2023), indicating severe non-carcinogenic health risks despite a slight temporal improvement. Spatially, contamination increased from upstream to downstream, with midstream and downstream areas acting as critical hotspots. Temporally, although pollutant levels declined in 2023, they remained significantly above safe limits, demonstrating limited natural recovery. Overall, the findings provide clear evidence of the long-term persistence of conflict-related contamination and its sustained risks to human health. This study highlights the need for targeted remediation strategies and offers a transferable framework for assessing water quality in conflict-affected river systems.:
Experimentelle Modellbildung synthetischer Faserseile zur Schlupfkompensation für die Anwendung in Seilrobotern
(Stuttgart : Fraunhofer Verlag, 2026) Reichenbach, Thomas; Pott, Andreas (Hon.-Prof. Dr.-Ing.)
Synthetische Faserseile ermöglichen in Seilrobotern und Fördersystemen leichte, kompakte Antriebslösungen. Die Positionsgenauigkeit dieser Seilantriebe wird durch den auftretenden Seilschlupf begrenzt. Diese Arbeit untersucht systematisch das Reibungs- und Schlupfverhalten geflochtener Faserseile aus HMPE, Flüssigkristallpolymer und Polyester in Trommelwinden. Auf speziell entwickelten Seiltriebprüfständen werden empirische Reibungs- und Schlupfmodelle experimentell identifiziert und validiert. Die gewonnenen Modelle bilden die Grundlage für eine modellbasierte Vorsteuerung zur Schlupfkompensation, die ausschließlich antriebsseitige Messsignale nutzt und ohne zusätzliche Sensorik am Abtrieb auskommt. Die Validierungsergebnisse belegen die Wirksamkeit des Ansatzes und leisten damit einen Beitrag zur Genauigkeitssteigerung mechatronischer Seiltriebsysteme.
A comparison of cost-effective sensors for a fluorescence-based detection system used in biodiagnostic devices
(2026) Vornweg, Rebecca; Decool, Christian; Hemmer, Moritz; Stollfuss, Bastian; Guenther, Thomas; Löffler, Ann-Kathrin; Kontermann, Roland E.; Zimmermann, André
Cost-effective, fluorescence-based biodiagnostic devices have the potential to expand point-of-care (POC) testing in resource-limited settings, thereby creating new opportunities for accessible and decentralised diagnostics. The objective of this study is to investigate the performance of a newly designed and simplified system that uses several cost-effective sensors for use in a fluorescence-based biodiagnostic setup. A collecting setup that includes an elliptical mirror to focus emitted fluorescence onto the semiconductor sensors was designed for an intensity-based readout. The readout was realised by various photodiodes, photoresistors, phototransistors and one multi-pixel photon counter (MPPC). Over a range of fluorophore concentrations using serial dilutions of Rhodamine B (RhB), the limit of detection (LOD) and limit of quantification (LOQ) at system level were evaluated. With the exception of the photodiodes, the system demonstrated promising performance with all sensors. The system using the photoresistors achieved the lowest LOD but showed limited repeatability, while the system using the MPPC and phototransistors exhibited high repeatability. A proof-of-concept demonstrated the feasibility of a photoresistor-based configuration by using a sandwich immunoassay for the detection of the antigen Human Epidermal growth factor Receptor 2 (HER2) (100 nM). While this study has not yet encompassed the full spectrum of clinically relevant concentrations, it has yielded valuable insights to enable further enhancements, without the necessity for highly specialised or costly equipment. The limitations and necessary improvements for further developments are discussed.
Ultrasensitive label-free detection of free thyroxine (T4) in physiological ranges using aptamer-functionalized silicon nanowire field effect transistors
(2026) Klinghammer, Stephanie; Butko, Wiana; Parichenko, Alexandra; Kastrati, Gylxhane; Herbawi, Abdallh; Riemenschneider, Leif; Cuniberti, Gianaurelio
Thyroxine (T4) is a key hormone regulating metabolic, cardiovascular, and neurodevelopmental processes, yet its clinical quantification still relies on centralized immunoassays that limit rapid or point-of-care monitoring. Here, we present a label-free biosensing platform based on silicon nanowire field-effect transistors (SiNW-FETs) functionalized with a T4-selective DNA aptamer via a 3-Triethoxysilyl propylsuccinic Anhydride (TESPSA)-mediated silanization approach, enabling a streamlined two-step modification for oriented immobilization. The biosensor achieves robust real-time detection of T4 across the physiological concentration range (5-30 pM), with a limit of detection of ~5 pM and a strong linear correlation between drain current and analyte concentration (R 2 = 0.9931). Specificity is confirmed using non-functionalized devices and estradiol as a non-target control. All measurements were performed in undiluted phosphate-buffered saline, representing a physiologically relevant ionic environment and demonstrating stable sensor performance under realistic buffer conditions. The dose-response behavior follows a Hill model, allowing extraction of binding parameters and confirming that the electrical signal originates from specific aptamer-target interactions. These results demonstrate that aptamer-functionalized SiNW-FETs provide a highly sensitive, selective, and miniaturizable platform for quantitative thyroid hormone monitoring, with strong potential for future point-of-care applications.
Modification of a scaled flight demonstrator for the implementation and experimental investigation of an energy harvesting powertrain in distributed electric propulsion systems
(2026) Kuhn, Achim; Nussbaumer, Eskil Jonas; Denzel, Jan; Bergmann, Dominique Paul; Strohmayer, Andreas
Distributed electric propulsion (DEP) systems offer a wide range of options for arranging the propulsion units on an aircraft. In most cases, the position of the propulsion systems is optimized for one specific flight phase, e.g., takeoff or cruise. Taking advantage of the high lift potential of the DEP also during descent and approach phases represents a challenge due to increased thrust. Energy harvesting propellers (EHPs) can be used to adapt the resulting thrust, by generation an additional drag force while regenerating a certain amount of energy back into the system. Therefore, the scaled flight demonstrator (SFD) e-Genius-Mod was modified to implement an energy harvesting powertrain in a DEP system. The energy harvesting wingtip propellers are integrated in a pusher configuration. It is possible to investigate different operation modes for recuperation, such as Windmilling and Opposite Pitch, by adjusting different propeller pitch angles. The electronics used for the wingtip propellers (WTPs) enable the control and measurement of the recuperation performance and furthermore to charge recuperated energy back into the battery. The energy harvesting system was tested in a wind tunnel to verify its functionality. In Windmilling mode, the maximum mean electrical power output is −25.7 W. In Opposite Pitch mode, the values were significantly higher, with a maximum mean electrical power of −184 W. This corresponds to up to seven times as much regenerated power in Opposite Pitch mode.