TY - CHAP A1 - Alhaskir, Mohamed A1 - Tschesche, Matteo A1 - Linke, Florian A1 - Schriewer, Elisabeth A1 - Weber, Yvonne A1 - Wolking, Stefan A1 - Röhrig, Rainer A1 - Koch, Henner A1 - Kutafina, Ekaterina ED - Röhrig, Rainer ED - Grabe, Niels ED - Haag, Martin ED - Hübner, Ursula ED - Sax, Ulrich ED - Schmidt, Carsten Oliver ED - Sedlmayr, Martin ED - Zapf, Antonia T1 - ECG matching: an approach to synchronize ECG datasets for data quality comparisons T2 - Proceedings of the 68th Annual Meeting of the German Association of Medical Informatics, Biometry, and Epidemiology e.V. (gmds) 2023 N2 - Clinical assessment of newly developed sensors is important for ensuring their validity. Comparing recordings of emerging electrocardiography (ECG) systems to a reference ECG system requires accurate synchronization of data from both devices. Current methods can be inefficient and prone to errors. To address this issue, three algorithms are presented to synchronize two ECG time series from different recording systems: Binned R-peak Correlation, R-R Interval Correlation, and Average R-peak Distance. These algorithms reduce ECG data to their cyclic features, mitigating inefficiencies and minimizing discrepancies between different recording systems. We evaluate the performance of these algorithms using high-quality data and then assess their robustness after manipulating the R-peaks. Our results show that R-R Interval Correlation was the most efficient, whereas the Average R-peak Distance and Binned R-peak Correlation were more robust against noisy data. KW - Electrocardiography KW - Wearable electronic device KW - Sensors comparison KW - Time-series synchronization Y1 - 2023 SN - 978-1-64368-428-4 (Print) SN - 978-1-64368-429-1 (Online) U6 - https://doi.org/10.3233/SHTI230718 N1 - Proceedings of the 68th Annual Meeting of the German Association of Medical Informatics, Biometry, and Epidemiology e.V. (gmds) 2023, 17. - 21.9.23, Heilbronn, Germany Part of the series: Studies in Health Technology and Informatics VL - 307 SP - 225 EP - 232 PB - IOS Press ER - TY - JOUR A1 - Wiegner, Jonas A1 - Volker, Hanno A1 - Mainz, Fabian A1 - Backes, Andreas A1 - Loeken, Michael A1 - Hüning, Felix T1 - Energy analysis of a wireless sensor node powered by a Wiegand sensor JF - Journal of Sensors and Sensor Systems (JSSS) N2 - This article describes an Internet of things (IoT) sensing device with a wireless interface which is powered by the energy-harvesting method of the Wiegand effect. The Wiegand effect, in contrast to continuous sources like photovoltaic or thermal harvesters, provides small amounts of energy discontinuously in pulsed mode. To enable an energy-self-sufficient operation of the sensing device with this pulsed energy source, the output energy of the Wiegand generator is maximized. This energy is used to power up the system and to acquire and process data like position, temperature or other resistively measurable quantities as well as transmit these data via an ultra-low-power ultra-wideband (UWB) data transmitter. A proof-of-concept system was built to prove the feasibility of the approach. The energy consumption of the system during start-up was analysed, traced back in detail to the individual components, compared to the generated energy and processed to identify further optimization options. Based on the proof of concept, an application prototype was developed. Y1 - 2023 U6 - https://doi.org/10.5194/jsss-12-85-2023 SN - 2194-878X N1 - Corresponding author: Felix Hüning VL - 12 IS - 1 SP - 85 EP - 92 PB - Copernicus Publ. CY - Göttingen ER - TY - CHAP A1 - Lahrs, Lennart A1 - Krisam, Pierre A1 - Herrmann, Ulf T1 - Envisioning a collaborative energy system planning platform for the energy transition at the district level T2 - ECOS 2023. The 36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems N2 - Residential and commercial buildings account for more than one-third of global energy-related greenhouse gas emissions. Integrated multi-energy systems at the district level are a promising way to reduce greenhouse gas emissions by exploiting economies of scale and synergies between energy sources. Planning district energy systems comes with many challenges in an ever-changing environment. Computational modelling established itself as the state-of-the-art method for district energy system planning. Unfortunately, it is still cumbersome to combine standalone models to generate insights that surpass their original purpose. Ideally, planning processes could be solved by using modular tools that easily incorporate the variety of competing and complementing computational models. Our contribution is a vision for a collaborative development and application platform for multi-energy system planning tools at the district level. We present challenges of district energy system planning identified in the literature and evaluate whether this platform can help to overcome these challenges. Further, we propose a toolkit that represents the core technical elements of the platform. Lastly, we discuss community management and its relevance for the success of projects with collaboration and knowledge sharing at their core. KW - Energy system planning KW - District energy planning platform KW - District data model KW - Renewable energy integration Y1 - 2023 U6 - https://doi.org/10.52202/069564-0284 N1 - ECOS 2023. The 36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, 25-30 JUNE, 2023, Las Palmas de Gran Canaria, Spain SP - 3163 EP - 3170 PB - Procedings of ECOS 2023 ER - TY - CHAP A1 - Klöser, Lars A1 - Büsgen, André A1 - Kohl, Philipp A1 - Kraft, Bodo A1 - Zündorf, Albert ED - Conte, Donatello ED - Fred, Ana ED - Gusikhin, Oleg ED - Sansone, Carlo T1 - Explaining relation classification models with semantic extents T2 - Deep Learning Theory and Applications N2 - In recent years, the development of large pretrained language models, such as BERT and GPT, significantly improved information extraction systems on various tasks, including relation classification. State-of-the-art systems are highly accurate on scientific benchmarks. A lack of explainability is currently a complicating factor in many real-world applications. Comprehensible systems are necessary to prevent biased, counterintuitive, or harmful decisions. We introduce semantic extents, a concept to analyze decision patterns for the relation classification task. Semantic extents are the most influential parts of texts concerning classification decisions. Our definition allows similar procedures to determine semantic extents for humans and models. We provide an annotation tool and a software framework to determine semantic extents for humans and models conveniently and reproducibly. Comparing both reveals that models tend to learn shortcut patterns from data. These patterns are hard to detect with current interpretability methods, such as input reductions. Our approach can help detect and eliminate spurious decision patterns during model development. Semantic extents can increase the reliability and security of natural language processing systems. Semantic extents are an essential step in enabling applications in critical areas like healthcare or finance. Moreover, our work opens new research directions for developing methods to explain deep learning models. KW - Relation classification KW - Natural language processing KW - Natural language understanding KW - Information extraction KW - Trustworthy artificial intelligence Y1 - 2023 SN - 978-3-031-39058-6 (Print) SN - 978-3-031-39059-3 (Online) U6 - https://doi.org/10.1007/978-3-031-39059-3_13 N1 - 4th International Conference, DeLTA 2023, Rome, Italy, July 13–14, 2023. SP - 189 EP - 208 PB - Springer CY - Cham ER - TY - JOUR A1 - Wendlandt, Tim A1 - Koch, Claudia A1 - Britz, Beate A1 - Liedek, Anke A1 - Schmidt, Nora A1 - Werner, Stefan A1 - Gleba, Yuri A1 - Vahidpour, Farnoosh A1 - Welden, Melanie A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Facile Purification and Use of Tobamoviral Nanocarriers for Antibody-Mediated Display of a Two-Enzyme System JF - Viruses N2 - Immunosorbent turnip vein clearing virus (TVCV) particles displaying the IgG-binding domains D and E of Staphylococcus aureus protein A (PA) on every coat protein (CP) subunit (TVCVPA) were purified from plants via optimized and new protocols. The latter used polyethylene glycol (PEG) raw precipitates, from which virions were selectively re-solubilized in reverse PEG concentration gradients. This procedure improved the integrity of both TVCVPA and the wild-type subgroup 3 tobamovirus. TVCVPA could be loaded with more than 500 IgGs per virion, which mediated the immunocapture of fluorescent dyes, GFP, and active enzymes. Bi-enzyme ensembles of cooperating glucose oxidase and horseradish peroxidase were tethered together on the TVCVPA carriers via a single antibody type, with one enzyme conjugated chemically to its Fc region, and the other one bound as a target, yielding synthetic multi-enzyme complexes. In microtiter plates, the TVCVPA-displayed sugar-sensing system possessed a considerably increased reusability upon repeated testing, compared to the IgG-bound enzyme pair in the absence of the virus. A high coverage of the viral adapters was also achieved on Ta2O5 sensor chip surfaces coated with a polyelectrolyte interlayer, as a prerequisite for durable TVCVPA-assisted electrochemical biosensing via modularly IgG-assembled sensor enzymes. KW - biosensor KW - horseradish peroxidase (HRP) KW - glucose oxidase (GOx) KW - enzyme cascade KW - turnip vein clearing virus (TVCV) KW - tobacco mosaic virus (TMV) Y1 - 2023 U6 - https://doi.org/doi.org/10.3390/v15091951 SN - 1999-4915 N1 - This article belongs to the Special Issue "Tobamoviruses 2023" VL - 9 IS - 15 PB - MDPI CY - Basel ER - TY - JOUR A1 - Baader, Fabian A1 - Boxberg, Marc S. A1 - Chen, Qian A1 - Förstner, Roger A1 - Kowalski, Julia A1 - Dachwald, Bernd T1 - Field-test performance of an ice-melting probe in a terrestrial analogue environment JF - Icarus N2 - Melting probes are a proven tool for the exploration of thick ice layers and clean sampling of subglacial water on Earth. Their compact size and ease of operation also make them a key technology for the future exploration of icy moons in our Solar System, most prominently Europa and Enceladus. For both mission planning and hardware engineering, metrics such as efficiency and expected performance in terms of achievable speed, power requirements, and necessary heating power have to be known. Theoretical studies aim at describing thermal losses on the one hand, while laboratory experiments and field tests allow an empirical investigation of the true performance on the other hand. To investigate the practical value of a performance model for the operational performance in extraterrestrial environments, we first contrast measured data from terrestrial field tests on temperate and polythermal glaciers with results from basic heat loss models and a melt trajectory model. For this purpose, we propose conventions for the determination of two different efficiencies that can be applied to both measured data and models. One definition of efficiency is related to the melting head only, while the other definition considers the melting probe as a whole. We also present methods to combine several sources of heat loss for probes with a circular cross-section, and to translate the geometry of probes with a non-circular cross-section to analyse them in the same way. The models were selected in a way that minimizes the need to make assumptions about unknown parameters of the probe or the ice environment. The results indicate that currently used models do not yet reliably reproduce the performance of a probe under realistic conditions. Melting velocities and efficiencies are constantly overestimated by 15 to 50 % in the models, but qualitatively agree with the field test data. Hence, losses are observed, that are not yet covered and quantified by the available loss models. We find that the deviation increases with decreasing ice temperature. We suspect that this mismatch is mainly due to the too restrictive idealization of the probe model and the fact that the probe was not operated in an efficiency-optimized manner during the field tests. With respect to space mission engineering, we find that performance and efficiency models must be used with caution in unknown ice environments, as various ice parameters have a significant effect on the melting process. Some of these are difficult to estimate from afar. Y1 - 2023 U6 - https://doi.org/10.1016/j.icarus.2023.115852 N1 - Forschungsdaten hierzu: "Performance data of an ice-melting probe from field tests in two different ice environments" (https://opus.bibliothek.fh-aachen.de/opus4/frontdoor/index/index/docId/10890) IS - 409 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hammer, Thorben A1 - Quitter, Julius A1 - Mayntz, Joscha A1 - Bauschat, J.-Michael A1 - Dahmann, Peter A1 - Götten, Falk A1 - Hille, Sebastian A1 - Stumpf, Eike T1 - Free fall drag estimation of small-scale multirotor unmanned aircraft systems using computational fluid dynamics and wind tunnel experiments JF - CEAS Aeronautical Journal N2 - New European Union (EU) regulations for UAS operations require an operational risk analysis, which includes an estimation of the potential danger of the UAS crashing. A key parameter for the potential ground risk is the kinetic impact energy of the UAS. The kinetic energy depends on the impact velocity of the UAS and, therefore, on the aerodynamic drag and the weight during free fall. Hence, estimating the impact energy of a UAS requires an accurate drag estimation of the UAS in that state. The paper at hand presents the aerodynamic drag estimation of small-scale multirotor UAS. Multirotor UAS of various sizes and configurations were analysed with a fully unsteady Reynolds-averaged Navier–Stokes approach. These simulations included different velocities and various fuselage pitch angles of the UAS. The results were compared against force measurements performed in a subsonic wind tunnel and provided good consistency. Furthermore, the influence of the UAS`s fuselage pitch angle as well as the influence of fixed and free spinning propellers on the aerodynamic drag was analysed. Free spinning propellers may increase the drag by up to 110%, depending on the fuselage pitch angle. Increasing the fuselage pitch angle of the UAS lowers the drag by 40% up to 85%, depending on the UAS. The data presented in this paper allow for increased accuracy of ground risk assessments. KW - Multirotor UAS KW - Drag estimation KW - CFD KW - Wind tunnel experiments KW - Wind milling Y1 - 2023 U6 - https://doi.org/10.1007/s13272-023-00702-w SN - 1869-5590 (Online) SN - 1869-5582 (Print) N1 - Corresponding author: Thorben Hammer PB - Springer CY - Wien ER - TY - CHAP A1 - Büsgen, André A1 - Klöser, Lars A1 - Kohl, Philipp A1 - Schmidts, Oliver A1 - Kraft, Bodo A1 - Zündorf, Albert ED - Cuzzocrea, Alfredo ED - Gusikhin, Oleg ED - Hammoudi, Slimane ED - Quix, Christoph T1 - From cracked accounts to fake IDs: user profiling on German telegram black market channels T2 - Data Management Technologies and Applications N2 - Messenger apps like WhatsApp and Telegram are frequently used for everyday communication, but they can also be utilized as a platform for illegal activity. Telegram allows public groups with up to 200.000 participants. Criminals use these public groups for trading illegal commodities and services, which becomes a concern for law enforcement agencies, who manually monitor suspicious activity in these chat rooms. This research demonstrates how natural language processing (NLP) can assist in analyzing these chat rooms, providing an explorative overview of the domain and facilitating purposeful analyses of user behavior. We provide a publicly available corpus of annotated text messages with entities and relations from four self-proclaimed black market chat rooms. Our pipeline approach aggregates the extracted product attributes from user messages to profiles and uses these with their sold products as features for clustering. The extracted structured information is the foundation for further data exploration, such as identifying the top vendors or fine-granular price analyses. Our evaluation shows that pretrained word vectors perform better for unsupervised clustering than state-of-the-art transformer models, while the latter is still superior for sequence labeling. KW - Clustering KW - Natural language processing KW - Information extraction KW - Profile extraction KW - Text mining Y1 - 2023 SN - 978-3-031-37889-8 (Print) SN - 978-3-031-37890-4 (Online) U6 - https://doi.org/10.1007/978-3-031-37890-4_9 N1 - 10th International Conference, DATA 2021, Virtual Event, July 6–8, 2021, and 11th International Conference, DATA 2022, Lisbon, Portugal, July 11-13, 2022 SP - 176 EP - 202 PB - Springer CY - Cham ER - TY - CHAP A1 - Schulte, Jonas A1 - Schwager, Christian A1 - Noureldin, Kareem A1 - May, Martin A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Gradient controlled startup procedure of a molten-salt power-to-heat energy storage plant based on dynamic process simulation T2 - SolarPACES: Solar Power & Chemical Energy Systems N2 - The integration of high temperature thermal energy storages into existing conventional power plants can help to reduce the CO2 emissions of those plants and lead to lower capital expenditures for building energy storage systems, due to the use of synergy effects [1]. One possibility to implement that, is a molten salt storage system with a powerful power-to-heat unit. This paper presents two possible control concepts for the startup of the charging system of such a facility. The procedures are implemented in a detailed dynamic process model. The performance and safety regarding the film temperatures at heat transmitting surfaces are investigated in the process simulations. To improve the accuracy in predicting the film temperatures, CFD simulations of the electrical heater are carried out and the results are merged with the dynamic model. The results show that both investigated control concepts are safe regarding the temperature limits. The gradient controlled startup performed better than the temperature-controlled startup. Nevertheless, there are several uncertainties that need to be investigated further. KW - Power plants KW - Energy storage KW - Associated liquids Y1 - 2023 SN - 978-0-7354-4623-6 U6 - https://doi.org/10.1063/5.0148741 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27 September–1 October 2021, Online IS - 2815 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - JOUR A1 - Cheng, Chi-Tsun A1 - Wollert, Jörg A1 - Chen, Xi A1 - Fapojuwo, Abraham O. T1 - Guest Editorial : Circuits and Systems for Industry X.0 Applications JF - IEEE Journal on Emerging and Selected Topics in Circuits and Systems Y1 - 2023 U6 - https://doi.org/10.1109/JETCAS.2023.3278843 SN - 2156-3357 (Print) SN - 2156-3365 (Online) VL - 13 SP - 457 EP - 460 PB - IEEE CY - New York ET - 2 ER - TY - CHAP A1 - Freyer, Nils A1 - Thewes, Dustin A1 - Meinecke, Matthias ED - Gusikhin, Oleg ED - Hammoudi, Slimane ED - Cuzzocrea, Alfredo T1 - GUIDO: a hybrid approach to guideline discovery & ordering from natural language texts T2 - Proceedings of the 12th International Conference on Data Science, Technology and Applications DATA - Volume 1 N2 - Extracting workflow nets from textual descriptions can be used to simplify guidelines or formalize textual descriptions of formal processes like business processes and algorithms. The task of manually extracting processes, however, requires domain expertise and effort. While automatic process model extraction is desirable, annotating texts with formalized process models is expensive. Therefore, there are only a few machine-learning-based extraction approaches. Rule-based approaches, in turn, require domain specificity to work well and can rarely distinguish relevant and irrelevant information in textual descriptions. In this paper, we present GUIDO, a hybrid approach to the process model extraction task that first, classifies sentences regarding their relevance to the process model, using a BERT-based sentence classifier, and second, extracts a process model from the sentences classified as relevant, using dependency parsing. The presented approach achieves significantly better resul ts than a pure rule-based approach. GUIDO achieves an average behavioral similarity score of 0.93. Still, in comparison to purely machine-learning-based approaches, the annotation costs stay low. KW - Natural Language Processing KW - Text Mining KW - Process Model Extraction KW - Business Process Intelligence Y1 - 2023 SN - 978-989-758-664-4 U6 - https://doi.org/10.5220/0012084400003541 SN - 2184-285X N1 - 12th International Conference on Data Science, Technology and Applications, July 11-13, 2023, in Rome, Italy. SP - 335 EP - 342 ER - TY - JOUR A1 - Eggert, Mathias A1 - Kling, Rene T1 - How to distribute charging requests of electronic vehicles? A reservation-based approach JF - International Journal of Intelligent Transportation Systems Research N2 - The number of electronic vehicles increase steadily while the space for extending the charging infrastructure is limited. In particular in urban areas, where parking spaces in attractive areas are famous, opportunities to setup new charging stations is very limited. This leads to an overload of some very attractive charging stations and an underutilization of less attractive ones. Against this background, the paper at hand presents the design of an e-vehicle reservation system that aims at distributing the utilization of the charging infrastructure, particularly in urban areas. By applying a design science approach, the requirements for a reservation-based utilization approach are elicited and a model for a suitable distribution approach and its instantiation are developed. The artefact is evaluated by simulating the distribution effects based on data of real charging station utilizations. KW - Simulation KW - Parking KW - Charging station KW - Utilization improvement KW - Reservation system KW - Electronic vehicle Y1 - 2023 U6 - https://doi.org/10.1007/s13177-023-00367-z SN - 1868-8659 N1 - Corresponding author: Mathias Eggert VL - 21 IS - 2023 SP - 437 EP - 460 PB - Springer CY - Berlin, Heidelberg, New York ER - TY - CHAP A1 - Baier, Ralph A1 - Brauner, Philipp A1 - Brillowski, Florian A1 - Dammers, Hannah A1 - Liehner, Luca A1 - Pütz, Sebastian A1 - Schneider, Sebastian A1 - Schollemann, Alexander A1 - Steuer-Dankert, Linda A1 - Vervier, Luisa A1 - Gries, Thomas A1 - Leicht-Scholten, Carmen A1 - Mertens, Alexander A1 - Nagel, Saskia K. A1 - Schuh, Günther A1 - Ziefle, Martina A1 - Nitsch, Verena ED - Brecher, Christian ED - Schuh, Günther ED - van der Alst, Wil ED - Jarke, Matthias ED - Piller, Frank T. ED - Padberg, Melanie T1 - Human-centered work design for the internet of production T2 - Internet of production - fundamentals, applications and proceedings N2 - Like all preceding transformations of the manufacturing industry, the large-scale usage of production data will reshape the role of humans within the sociotechnical production ecosystem. To ensure that this transformation creates work systems in which employees are empowered, productive, healthy, and motivated, the transformation must be guided by principles of and research on human-centered work design. Specifically, measures must be taken at all levels of work design, ranging from (1) the work tasks to (2) the working conditions to (3) the organizational level and (4) the supra-organizational level. We present selected research across all four levels that showcase the opportunities and requirements that surface when striving for human-centered work design for the Internet of Production (IoP). (1) On the work task level, we illustrate the user-centered design of human-robot collaboration (HRC) and process planning in the composite industry as well as user-centered design factors for cognitive assistance systems. (2) On the working conditions level, we present a newly developed framework for the classification of HRC workplaces. (3) Moving to the organizational level, we show how corporate data can be used to facilitate best practice sharing in production networks, and we discuss the implications of the IoP for new leadership models. Finally, (4) on the supra-organizational level, we examine overarching ethical dimensions, investigating, e.g., how the new work contexts affect our understanding of responsibility and normative values such as autonomy and privacy. Overall, these interdisciplinary research perspectives highlight the importance and necessary scope of considering the human factor in the IoP. KW - Responsibility KW - Privacy KW - Digital leadership KW - Best practice sharing KW - Cognitive assistance system KW - Human-robot collaboration KW - Human-centered work design Y1 - 2023 SN - 978-3-030-98062-7 U6 - https://doi.org/10.1007/978-3-030-98062-7_19-1 N1 - Part of the book series: Interdisciplinary Excellence Accelerator Series (IDEAS) SP - 1 EP - 23 PB - Springer CY - Cham ER - TY - CHAP A1 - Funke, Harald A1 - Beckmann, Nils A1 - Stefan, Lukas A1 - Keinz, Jan T1 - Hydrogen combustor integration study for a medium range aircraft engine using the dry-low NOx “Micromix” combustion principle T2 - Proceedings of the ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition. Volume 1: Aircraft Engine. N2 - The feasibility study presents results of a hydrogen combustor integration for a Medium-Range aircraft engine using the Dry-Low-NOₓ Micromix combustion principle. Based on a simplified Airbus A320-type flight mission, a thermodynamic performance model of a kerosene and a hydrogen-powered V2530-A5 engine is used to derive the thermodynamic combustor boundary conditions. A new combustor design using the Dry-Low NOx Micromix principle is investigated by slice model CFD simulations of a single Micromix injector for design and off-design operation of the engine. Combustion characteristics show typical Micromix flame shapes and good combustion efficiencies for all flight mission operating points. Nitric oxide emissions are significant below ICAO CAEP/8 limits. For comparison of the Emission Index (EI) for NOₓ emissions between kerosene and hydrogen operation, an energy (kerosene) equivalent Emission Index is used. A full 15° sector model CFD simulation of the combustion chamber with multiple Micromix injectors including inflow homogenization and dilution and cooling air flows investigates the combustor integration effects, resulting NOₓ emission and radial temperature distributions at the combustor outlet. The results show that the integration of a Micromix hydrogen combustor in actual aircraft engines is feasible and offers, besides CO₂ free combustion, a significant reduction of NOₓ emissions compared to kerosene operation. KW - emission index KW - nitric oxides KW - aircraft engine KW - Micromix KW - combustion KW - hydrogen Y1 - 2023 SN - 978-0-7918-8693-9 U6 - https://doi.org/10.1115/GT2023-102370 N1 - Paper No. GT2023-102370, V001T01A022 N1 - ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition June 26–30, 2023, Boston, Massachusetts, USA PB - ASME CY - New York ER - TY - CHAP A1 - Dachwald, Bernd A1 - Ulamec, Stephan A1 - Kowalski, Julia A1 - Boxberg, Marc S. A1 - Baader, Fabian A1 - Biele, Jens A1 - Kömle, Norbert ED - Badescu, Viorel ED - Zacny, Kris ED - Bar-Cohen, Yoseph T1 - Ice melting probes T2 - Handbook of Space Resources N2 - The exploration of icy environments in the solar system, such as the poles of Mars and the icy moons (a.k.a. ocean worlds), is a key aspect for understanding their astrobiological potential as well as for extraterrestrial resource inspection. On these worlds, ice melting probes are considered to be well suited for the robotic clean execution of such missions. In this chapter, we describe ice melting probes and their applications, the physics of ice melting and how the melting behavior can be modeled and simulated numerically, the challenges for ice melting, and the required key technologies to deal with those challenges. We also give an overview of existing ice melting probes and report some results and lessons learned from laboratory and field tests. KW - Ice melting probe KW - Ice penetration KW - Icy moons KW - Ocean worlds KW - Mars Y1 - 2023 SN - 978-3-030-97912-6 (Print) SN - 978-3-030-97913-3 (Online) U6 - https://doi.org/10.1007/978-3-030-97913-3_29 SP - 955 EP - 996 PB - Springer CY - Cham ER - TY - THES A1 - Bung, Daniel Bernhard T1 - Imaging techniques for investigation of free-surface flows in hydraulic laboratories N2 - This thesis aims at the presentation and discussion of well-accepted and new imaging techniques applied to different types of flow in common hydraulic engineering environments. All studies are conducted in laboratory conditions and focus on flow depth and velocity measurements. Investigated flows cover a wide range of complexity, e.g. propagation of waves, dam-break flows, slightly and fully aerated spillway flows as well as highly turbulent hydraulic jumps. Newimagingmethods are compared to different types of sensorswhich are frequently employed in contemporary laboratory studies. This classical instrumentation as well as the general concept of hydraulic modeling is introduced to give an overview on experimental methods. Flow depths are commonly measured by means of ultrasonic sensors, also known as acoustic displacement sensors. These sensors may provide accurate data with high sample rates in case of simple flow conditions, e.g. low-turbulent clear water flows. However, with increasing turbulence, higher uncertainty must be considered. Moreover, ultrasonic sensors can provide point data only, while the relatively large acoustic beam footprint may lead to another source of uncertainty in case of relatively short, highly turbulent surface fluctuations (ripples) or free-surface air-water flows. Analysis of turbulent length and time scales of surface fluctuations from point measurements is also difficult. Imaging techniques with different dimensionality, however, may close this gap. It is shown in this thesis that edge detection methods (known from computer vision) may be used for two-dimensional free-surface extraction (i.e. from images taken through transparant sidewalls in laboratory flumes). Another opportunity in hydraulic laboratory studies comes with the application of stereo vision. Low-cost RGB-D sensors can be used to gather instantaneous, three-dimensional free-surface elevations, even in flows with very high complexity (e.g. aerated hydraulic jumps). It will be shown that the uncertainty of these methods is of similar order as for classical instruments. Particle Image Velocimetry (PIV) is a well-accepted and widespread imaging technique for velocity determination in laboratory conditions. In combination with high-speed cameras, PIV can give time-resolved velocity fields in 2D/3D or even as volumetric flow fields. PIV is based on a cross-correlation technique applied to small subimages of seeded flows. The minimum size of these subimages defines the maximum spatial resolution of resulting velocity fields. A derivative of PIV for aerated flows is also available, i.e. the so-called Bubble Image Velocimetry (BIV). This thesis emphasizes the capacities and limitations of both methods, using relatively simple setups with halogen and LED illuminations. It will be demonstrated that PIV/BIV images may also be processed by means of Optical Flow (OF) techniques. OF is another method originating from the computer vision discipline, based on the assumption of image brightness conservation within a sequence of images. The Horn-Schunck approach, which has been first employed to hydraulic engineering problems in the studies presented herein, yields dense velocity fields, i.e. pixelwise velocity data. As discussed hereinafter, the accuracy of OF competes well with PIV for clear-water flows and even improves results (compared to BIV) for aerated flow conditions. In order to independently benchmark the OF approach, synthetic images with defined turbulence intensitiy are used. Computer vision offers new opportunities that may help to improve the understanding of fluid mechanics and fluid-structure interactions in laboratory investigations. In prototype environments, it can be employed for obstacle detection (e.g. identification of potential fish migration corridors) and recognition (e.g. fish species for monitoring in a fishway) or surface reconstruction (e.g. inspection of hydraulic structures). It can thus be expected that applications to hydraulic engineering problems will develop rapidly in near future. Current methods have not been developed for fluids in motion. Systematic future developments are needed to improve the results in such difficult conditions. Y1 - 2023 U6 - https://doi.org/10.25926/BUW/0-172 ER - TY - JOUR A1 - Böhnert, Arno A1 - Blaschke, Florian A1 - Biewendt, Marcel T1 - Impact of sustainability on the strategic direction of luxury companies JF - European Journal of Marketing and Economics N2 - Today’s society is undergoing a paradigm shift driven by the megatrend of sustainability. This undeniably affects all areas of Western life. This paper aims to find out how the luxury industry is dealing with this change and what adjustments are made by the companies. For this purpose, interviews were conducted with managers from the luxury industry, in which they were asked about specific measures taken by their companies as well as trends in the industry. In a subsequent evaluation, the trends in the luxury industry were summarized for the areas of ecological, social, and economic sustainability. It was found that the area of environmental sustainability is significantly more focused than the other sub-areas. Furthermore, the need for a customer survey to validate the industry-based measures was identified. KW - Operations KW - Brands KW - Luxury KW - Change Y1 - 2022 SN - 2601-8659 VL - 6 IS - 1 SP - 70 EP - 85 PB - Revistia CY - London ER - TY - CHAP A1 - Bung, Daniel Bernhard A1 - Langohr, Phillip A1 - Waldenberger, Lisa ED - Habersack, Helmut ED - Tritthart, Michael T1 - Influence of cycle number in CFD studies of labyrinth weirs T2 - Proceedings of the 40th IAHR World Congress (Vienna, 2023) N2 - The major advantage of labyrinth weirs over linear weirs is hydraulic efficiency. In hydraulic modeling efforts, this strength contrasts with limited pump capacity as well as limited computational power for CFD simulations. For the latter, reducing the number of investigated cycles can significantly reduce necessary computational time. In this study, a labyrinth weir with different cycle numbers was investigated. The simulations were conducted in FLOW-3D HYDRO as a Large Eddy Simulation. With a mean deviation of 1.75 % between simulated discharge coefficients and literature design equations, a reasonable agreement was found. For downstream conditions, overall consistent results were observed as well. However, the orientation of labyrinth weirs with a single cycle should be chosen carefully under consideration of the individual research purpose. KW - CFD KW - Large Eddy Simulation KW - Labyfrinth weirs Y1 - 2023 SN - 978-90-833476-1-5 U6 - https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0531-cd SN - L 2521-7119 (online) N1 - Vienna, Austria, from August 21 to 25, 2023 PB - International Association for Hydro-Environment Engineering and Research (IAHR) CY - Madrid ER - TY - JOUR A1 - Janus, Kevin Alexander A1 - Achtsnicht, Stefan A1 - Tempel, Laura A1 - Drinic, Aleksaner A1 - Kopp, Alexander A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Influence of fibroin membrane composition and curing parameters on the performance of a biodegradable enzymatic biosensor manufactured from Silicon-Free Carbon JF - Physica status solidi : pss. A, Applications and materials science N2 - Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen-printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5–10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior. KW - amperometric biosensors KW - biocompatible KW - biodegradabl KW - encapsulation materials KW - fibroin Y1 - 2023 U6 - https://doi.org/10.1002/pssa.202300081 SN - 1862-6300 (Print) SN - 1862-6319 (Online) N1 - Corresponding author: Michael J. Schöning VL - 220 IS - 22 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Šakić, Bogdan A1 - Marinković, Marko A1 - Butenweg, Christoph A1 - Klinkel, Sven ED - Yang, J. T1 - Influence of slab deflection on the out-of-plane capacity of unreinforced masonry partition walls JF - Engineering Structures N2 - Severe damage of non-structural elements is noticed in previous earthquakes, causing high economic losses and posing a life threat for the people. Masonry partition walls are one of the most commonly used non-structural elements. Therefore, their behaviour under earthquake loading in out-of-plane (OOP) direction is investigated by several researches in the past years. However, none of the existing experimental campaigns or analytical approaches consider the influence of prior slab deflection on OOP response of partition walls. Moreover, none of the existing construction techniques for the connection of partition walls with surrounding reinforced concrete (RC) is investigated for the combined slab deflection and OOP loading. However, the inevitable time-dependent behaviour of RC slabs leads to high values of final slab deflections which can further influence boundary conditions of partition walls. Therefore, a comprehensive study on the influence of slab deflection on the OOP capacity of masonry partitions is conducted. In the first step, experimental tests are carried out. Results of experimental tests are further used for the calibration of the numerical model employed for a parametric study. Based on the results, behaviour under combined loading for different construction techniques is explained. The results show that slab deflection leads either to severe damage or to a high reduction of OOP capacity. Existing practical solutions do not account for these effects. In this contribution, recommendations to overcome the problems of combined slab deflection and OOP loading on masonry partition walls are given. Possible interaction of in-plane (IP) loading, with the combined slab deflection and OOP loading on partition walls, is not investigated in this study. KW - Masonry partition walls KW - Earthquake KW - Out-of-plane capacity KW - Slab deflection Y1 - 2023 U6 - https://doi.org/10.1016/j.engstruct.2022.115342 SN - 0141-0296 VL - 276 PB - Elsevier CY - Amsterdam ER -