@incollection{Kleefeld2020, author = {Kleefeld, Andreas}, title = {Numerical calculation of interior transmission eigenvalues with mixed boundary conditions}, series = {Computational and Analytic Methods in Science and Engineering}, booktitle = {Computational and Analytic Methods in Science and Engineering}, editor = {Constanda, Christian}, publisher = {Birkh{\"a}user}, address = {Cham}, isbn = {978-3-030-48185-8 (Hardcover)}, doi = {10.1007/978-3-030-48186-5_9}, pages = {173 -- 195}, year = {2020}, abstract = {Interior transmission eigenvalue problems for the Helmholtz equation play an important role in inverse wave scattering. Some distribution properties of those eigenvalues in the complex plane are reviewed. Further, a new scattering model for the interior transmission eigenvalue problem with mixed boundary conditions is described and an efficient algorithm for computing the interior transmission eigenvalues is proposed. Finally, extensive numerical results for a variety of two-dimensional scatterers are presented to show the validity of the proposed scheme.}, language = {en} } @article{FingerBraunBil2020, author = {Finger, Felix and Braun, Carsten and Bil, Cees}, title = {Comparative assessment of parallel-hybrid-electric propulsion systems for four different aircraft}, series = {Journal of Aircraft}, volume = {57}, journal = {Journal of Aircraft}, number = {5}, publisher = {AIAA}, address = {Reston, Va.}, issn = {1533-3868}, doi = {10.2514/1.C035897}, year = {2020}, abstract = {Until electric energy storage systems are ready to allow fully electric aircraft, the combination of combustion engine and electric motor as a hybrid-electric propulsion system seems to be a promising intermediate solution. Consequently, the design space for future aircraft is expanded considerably, as serial hybrid-electric, parallel hybrid-electric, fully electric, and conventional propulsion systems must all be considered. While the best propulsion system depends on a multitude of requirements and considerations, trends can be observed for certain types of aircraft and certain types of missions. This Paper provides insight into some factors that drive a new design toward either conventional or hybrid propulsion systems. General aviation aircraft, regional transport aircraft vertical takeoff and landing air taxis, and unmanned aerial vehicles are chosen as case studies. Typical missions for each class are considered, and the aircraft are analyzed regarding their takeoff mass and primary energy consumption. For these case studies, a high-level approach is chosen, using an initial sizing methodology. Only parallel-hybrid-electric powertrains are taken into account. Aeropropulsive interaction effects are neglected. Results indicate that hybrid-electric propulsion systems should be considered if the propulsion system is sized by short-duration power constraints. However, if the propulsion system is sized by a continuous power requirement, hybrid-electric systems offer hardly any benefit.}, language = {en} } @inproceedings{PaulsenHoffstadtKrafftetal.2020, author = {Paulsen, Svea and Hoffstadt, Kevin and Krafft, Simone and Leite, A. and Zang, J. and Fonseca-Zang, W. and Kuperjans, Isabel}, title = {Continuous biogas production from sugarcane as sole substrate}, series = {Energy Reports}, volume = {6}, booktitle = {Energy Reports}, number = {Supplement 1}, publisher = {Elsevier}, doi = {10.1016/j.egyr.2019.08.035}, pages = {153 -- 158}, year = {2020}, abstract = {A German-Brazilian research project investigates sugarcane as an energy plant in anaerobic digestion for biogas production. The aim of the project is a continuous, efficient, and stable biogas process with sugarcane as the substrate. Tests are carried out in a fermenter with a volume of 10 l. In order to optimize the space-time load to achieve a stable process, a continuous process in laboratory scale has been devised. The daily feed in quantity and the harvest time of the substrate sugarcane has been varied. Analyses of the digester content were conducted twice per week to monitor the process: The ratio of inorganic carbon content to volatile organic acid content (VFA/TAC), the concentration of short-chain fatty acids, the organic dry matter, the pH value, and the total nitrogen, phosphate, and ammonium concentrations were monitored. In addition, the gas quality (the percentages of CO₂, CH₄, and H₂) and the quantity of the produced gas were analyzed. The investigations have exhibited feasible and economical production of biogas in a continuous process with energy cane as substrate. With a daily feeding rate of 1.68gᵥₛ/l*d the average specific gas formation rate was 0.5 m3/kgᵥₛ. The long-term study demonstrates a surprisingly fast metabolism of short-chain fatty acids. This indicates a stable and less susceptible process compared to other substrates.}, language = {en} } @article{OezsoyluKizildagSchoeningetal.2020, author = {{\"O}zsoylu, Dua and Kizildag, Sefa and Sch{\"o}ning, Michael Josef and Wagner, Torsten}, title = {Differential chemical imaging of extracellular acidification within microfluidic channels using a plasma-functionalized light-addressable potentiometric sensor (LAPS)}, series = {Physics in Medicine}, volume = {10}, journal = {Physics in Medicine}, number = {100030}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-4510}, doi = {10.1016/j.phmed.2020.100030}, pages = {8}, year = {2020}, abstract = {Extracellular acidification is a basic indicator for alterations in two vital metabolic pathways: glycolysis and cellular respiration. Measuring these alterations by monitoring extracellular acidification using cell-based biosensors such as LAPS plays an important role in studying these pathways whose disorders are associated with numerous diseases including cancer. However, the surface of the biosensors must be specially tailored to ensure high cell compatibility so that cells can represent more in vivo-like behavior, which is critical to gain more realistic in vitro results from the analyses, e.g., drug discovery experiments. In this work, O2 plasma patterning on the LAPS surface is studied to enhance surface features of the sensor chip, e.g., wettability and biofunctionality. The surface treated with O2 plasma for 30 s exhibits enhanced cytocompatibility for adherent CHO-K1 cells, which promotes cell spreading and proliferation. The plasma-modified LAPS chip is then integrated into a microfluidic system, which provides two identical channels to facilitate differential measurements of the extracellular acidification of CHO-K1 cells. To the best of our knowledge, it is the first time that extracellular acidification within microfluidic channels is quantitatively visualized as differential (bio-)chemical images.}, language = {en} } @inproceedings{SildatkeKarwanniKraftetal.2020, author = {Sildatke, Michael and Karwanni, Hendrik and Kraft, Bodo and Schmidts, Oliver and Z{\"u}ndorf, Albert}, title = {Automated Software Quality Monitoring in Research Collaboration Projects}, series = {ICSEW'20: Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops}, booktitle = {ICSEW'20: Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1145/3387940.3391478}, pages = {603 -- 610}, year = {2020}, abstract = {In collaborative research projects, both researchers and practitioners work together solving business-critical challenges. These projects often deal with ETL processes, in which humans extract information from non-machine-readable documents by hand. AI-based machine learning models can help to solve this problem. Since machine learning approaches are not deterministic, their quality of output may decrease over time. This fact leads to an overall quality loss of the application which embeds machine learning models. Hence, the software qualities in development and production may differ. Machine learning models are black boxes. That makes practitioners skeptical and increases the inhibition threshold for early productive use of research prototypes. Continuous monitoring of software quality in production offers an early response capability on quality loss and encourages the use of machine learning approaches. Furthermore, experts have to ensure that they integrate possible new inputs into the model training as quickly as possible. In this paper, we introduce an architecture pattern with a reference implementation that extends the concept of Metrics Driven Research Collaboration with an automated software quality monitoring in productive use and a possibility to auto-generate new test data coming from processed documents in production. Through automated monitoring of the software quality and auto-generated test data, this approach ensures that the software quality meets and keeps requested thresholds in productive use, even during further continuous deployment and changing input data.}, language = {en} } @techreport{Drescher2021, type = {Working Paper}, author = {Drescher, Hans Paul}, title = {Turbulence - minimum dissipation and maximum macroscopic momentum exchange}, pages = {44 Seiten}, year = {2021}, abstract = {The minimum dissipation requirement of the thermodynamics of irreversible processes is applied to characterize the existence of laminar and non-laminar, and the co-existence of laminar and turbulent flow zones. Local limitations of the different zones and three different forms of transition are defined. For the Couette flow a non-local "corpuscular" flow mechanism explains the logarithmic law-of-the-wall, maximum turbulent dimensions and a value x=0,415 for the v. K{\´a}rm{\´a}n constant. Limitations of the logarithmic law near the wall and in the centre of the experiment are interpreted.}, language = {en} } @article{BiewendtBlaschkeBoehnert2021, author = {Biewendt, Marcel and Blaschke, Florian and B{\"o}hnert, Arno}, title = {A review of contemporary challenges in business culture}, series = {International Journal of Applied Research in Business and Management}, volume = {2}, journal = {International Journal of Applied Research in Business and Management}, number = {1}, publisher = {Wohllebe \& Ross Publishing}, address = {Hamburg}, issn = {2700-8983}, doi = {10.51137/ijarbm.2021.2.1.1}, pages = {1 -- 12}, year = {2021}, abstract = {The following article deals with the basic principles of intercultural management and possible improvements in terms of cultural, ethnic and gender diversification. The results are exemplarily applied to a bank located in Germany. The aim of this paper is to find out to what extent intercultural management could improve the productivity of Relatos-Bank in dealing with foreign employees or employees with a different cultural background. To achieve this goal, the authors con-duct a literature research. The main sources of information are books, journal articles and internet sources. It becomes clear that especially the different perceptions of different generations have a potential for conflict, which can be counteracted by applying presented scientific models. Equalizing the salaries of female and male employees and equalizing the rights and distribution of power could also be the key to becoming an open-minded, dynamic and fair organization that is pre-pared for the rapidly changing environment in which it operates.}, language = {en} } @article{BiewendtBlaschkeBoehnert2021, author = {Biewendt, Marcel and Blaschke, Florian and B{\"o}hnert, Arno}, title = {Motivational factors in organisational change}, series = {SocioEconomic Challenges}, volume = {5}, journal = {SocioEconomic Challenges}, number = {3}, publisher = {ARMG}, address = {Sumy}, issn = {2520-6214}, doi = {10.21272/sec.5(3).15-27.2021}, pages = {15 -- 27}, year = {2021}, abstract = {The presented paper gives an overview of the most important and most common theories and concepts from the economic field of organisational change and is also enriched with quantitative publication data, which underlines the relevance of the topic. In particular, the topic presented is interwoven in an interdisciplinary way with economic psychological models, which are underpinned within the models with content from leading scholars in the field. The pace of change in companies is accelerating, as is technological change in our society. Adaptations of the corporate structure, but also of management techniques and tasks, are therefore indispensable. This includes not only the right approaches to employee motivation, but also the correct use of intrinsic and extrinsic motivational factors. Based on the hypothesis put forward by the scientist and researcher Rollinson in his book "Organisational behaviour and analysis" that managers believe motivational resources are available at all times, socio-economic and economic psychological theories are contrasted here in order to critically examine this statement. In addition, a fictitious company was created as a model for this work in order to illustrate the effects of motivational deficits in practice. In this context, the theories presented are applied to concrete problems within the model and conclusions are drawn about their influence and applicability. This led to the conclusion that motivation is a very individual challenge for each employee, which requires adapted and personalised approaches. On the other hand, the recommendations for action for supervisors in the case of motivation deficits also cannot be answered in a blanket manner, but can only be solved with the help of professional, expert-supported processing due to the economic-psychological realities of motivation. Identifying, analysing and remedying individual employee motivation deficits is, according to the authors, a problem and a challenge of great importance, especially in the context of rapidly changing ecosystems in modern companies, as motivation also influences other factors such as individual productivity. The authors therefore conclude that good motivation through the individual and customised promotion and further training of employees is an important point for achieving important corporate goals in order to remain competitive on the one hand and to create a productive and pleasant working environment on the other.}, language = {en} } @inproceedings{ButenwegMarinkovićPaveseetal.2021, author = {Butenweg, Christoph and Marinković, Marko and Pavese, Alberto and Lanese, Igor and Hoffmeister, Benno and Pinkawa, Marius and Vulcu, Mihai-Cristian and Bursi, Oreste and Nardin, Chiara and Paolacci, Fabrizio and Quinci, Gianluca and Fragiadakis, Michalis and Weber, Felix and Huber, Peter and Renault, Philippe and G{\"u}ndel, Max and Dyke, Shirley and Ciucci, M. and Marino, A.}, title = {Seismic performance of multi-component systems in special risk industrial facilities}, series = {Proceedings of the seventeenth world conference on earthquake engineering}, booktitle = {Proceedings of the seventeenth world conference on earthquake engineering}, year = {2021}, abstract = {Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of the process equipment and multiple and simultaneous release of hazardous substances in industrial facilities. Nevertheless, the design of industrial plants is inadequately described in recent codes and guidelines, as they do not consider the dynamic interaction between the structure and the installations and thus the effect of seismic response of the installations on the response of the structure and vice versa. The current code-based approach for the seismic design of industrial facilities is considered not enough for ensure proper safety conditions against exceptional event entailing loss of content and related consequences. Accordingly, SPIF project (Seismic Performance of Multi- Component Systems in Special Risk Industrial Facilities) was proposed within the framework of the European H2020 - SERA funding scheme (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The objective of the SPIF project is the investigation of the seismic behavior of a representative industrial structure equipped with complex process technology by means of shaking table tests. The test structure is a three-story moment resisting steel frame with vertical and horizontal vessels and cabinets, arranged on the three levels and connected by pipes. The dynamic behavior of the test structure and installations is investigated with and without base isolation. Furthermore, both firmly anchored and isolated components are taken into account to compare their dynamic behavior and interactions with each other. Artificial and synthetic ground motions are applied to study the seismic response at different PGA levels. After each test, dynamic identification measurements are carried out to characterize the system condition. The contribution presents the numerical simulations to calibrate the tests on the prototype, the experimental setup of the investigated structure and installations, selected measurement data and finally describes preliminary experimental results.}, language = {en} } @unpublished{RingersBialonskiSolovevetal.2021, author = {Ringers, Christa and Bialonski, Stephan and Solovev, Anton and Hansen, Jan N. and Ege, Mert and Friedrich, Benjamin M. and Jurisch-Yaksi, Nathalie}, title = {Preprint: Local synchronization of cilia and tissue-scale cilia alignment are sufficient for global metachronal waves}, series = {bioRxiv}, journal = {bioRxiv}, doi = {10.1101/2021.11.23.469646}, pages = {19 Seiten}, year = {2021}, abstract = {Motile cilia are hair-like cell extensions present in multiple organs of the body. How cilia coordinate their regular beat in multiciliated epithelia to move fluids remains insufficiently understood, particularly due to lack of rigorous quantification. We combine here experiments, novel analysis tools, and theory to address this knowledge gap. We investigate collective dynamics of cilia in the zebrafish nose, due to its conserved properties with other ciliated tissues and its superior accessibility for non-invasive imaging. We revealed that cilia are synchronized only locally and that the size of local synchronization domains increases with the viscosity of the surrounding medium. Despite the fact that synchronization is local only, we observed global patterns of traveling metachronal waves across the multiciliated epithelium. Intriguingly, these global wave direction patterns are conserved across individual fish, but different for left and right nose, unveiling a chiral asymmetry of metachronal coordination. To understand the implications of synchronization for fluid pumping, we used a computational model of a regular array of cilia. We found that local metachronal synchronization prevents steric collisions and improves fluid pumping in dense cilia carpets, but hardly affects the direction of fluid flow. In conclusion, we show that local synchronization together with tissue-scale cilia alignment are sufficient to generate metachronal wave patterns in multiciliated epithelia, which enhance their physiological function of fluid pumping.}, language = {en} } @inproceedings{ButenwegBursiNardinetal.2021, author = {Butenweg, Christoph and Bursi, Oreste S. and Nardin, Chiara and Lanese, Igor and Pavese, Alberto and Marinković, Marko and Paolacci, Fabrizio and Quinci, Gianluca}, title = {Experimental investigation on the seismic performance of a multi-component system for major-hazard industrial facilities}, series = {Conference Proceedings: Pressure Vessels \& Piping Conference Vol.5}, booktitle = {Conference Proceedings: Pressure Vessels \& Piping Conference Vol.5}, publisher = {American Society of Mechanical Engineers (ASME)}, address = {New York}, isbn = {9780791885352}, doi = {10.1115/PVP2021-61696}, pages = {8 Seiten}, year = {2021}, abstract = {Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of the process equipment and multiple and simultaneous release of hazardous substances in industrial facilities. Nevertheless, the design of industrial plants is inadequately described in recent codes and guidelines, as they do not consider the dynamic interaction between the structure and the installations and thus the effect of seismic response of the installations on the response of the structure and vice versa. The current code-based approach for the seismic design of industrial facilities is considered not enough for ensure proper safety conditions against exceptional event entailing loss of content and related consequences. Accordingly, SPIF project (Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities) was proposed within the framework of the European H2020 - SERA funding scheme (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The objective of the SPIF project is the investigation of the seismic behaviour of a representative industrial structure equipped with complex process technology by means of shaking table tests. The test structure is a three-story moment resisting steel frame with vertical and horizontal vessels and cabinets, arranged on the three levels and connected by pipes. The dynamic behaviour of the test structure and of its relative several installations is investigated. Furthermore, both process components and primary structure interactions are considered and analyzed. Several PGA-scaled artificial ground motions are applied to study the seismic response at different levels. After each test, dynamic identification measurements are carried out to characterize the system condition. The contribution presents the experimental setup of the investigated structure and installations, selected measurement data and describes the obtained damage. Furthermore, important findings for the definition of performance limits, the effectiveness of floor response spectra in industrial facilities will be presented and discussed.}, language = {en} } @inproceedings{FunkeBeckmannKeinzetal.2021, author = {Funke, Harald and Beckmann, Nils and Keinz, Jan and Horikawa, Atsushi}, title = {30 years of dry low NOx micromix combustor research for hydrogen-rich fuels: an overview of past and present activities}, series = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 4B: Combustion, Fuels, and Emissions}, booktitle = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 4B: Combustion, Fuels, and Emissions}, publisher = {ASME}, address = {New York, NY}, isbn = {978-0-7918-8413-3}, doi = {10.1115/GT2020-16328}, pages = {14 Seiten}, year = {2021}, abstract = {The paper presents an overview of the past and present of low-emission combustor research with hydrogen-rich fuels at Aachen University of Applied Sciences. In 1990, AcUAS started developing the Dry-Low-NOx Micromix combustion technology. Micromix reduces NOx emissions using jet-in-crossflow mixing of multiple miniaturized fuel jets and combustor air with an inherent safety against flashback. At first, pure hydrogen as fuel was investigated with lab-scale applications. Later, Micromix prototypes were developed for the use in an industrial gas turbine Honeywell/Garrett GTCP-36-300, proving low NOx characteristics during real gas turbine operation, accompanied by the successful definition of safety laws and control system modifications. Further, the Micromix was optimized for the use in annular and can combustors as well as for fuel-flexibility with hydrogen-methane-mixtures and hydrogen-rich syngas qualities by means of extensive experimental and numerical simulations. In 2020, the latest Micromix application will be demonstrated in a commercial 2 MW-class gas turbine can-combustor with full-scale engine operation. The paper discusses the advances in Micromix research over the last three decades.}, language = {en} } @inproceedings{MilijašŠakićMarinkovićetal.2021, author = {Milijaš, Aleksa and Šakić, Bogdan and Marinković, Marko and Butenweg, Christoph}, title = {Experimental investigation of behaviour of masonry infilled RC frames under out-of-plane loading}, series = {Proceedings of COMPDYN 2021}, booktitle = {Proceedings of COMPDYN 2021}, editor = {Papadrakakis, Manolis and Fragiadakis, Michalis}, publisher = {National Technical University of Athens}, address = {Athen}, isbn = {978-618-85072-5-8}, issn = {2623-3347}, doi = {10.7712/120121.8528.18914}, pages = {829 -- 846}, year = {2021}, abstract = {Masonry infills are commonly used as exterior or interior walls in reinforced concrete (RC) frame structures and they can be encountered all over the world, including earthquake prone regions. Since the middle of the 20th century the behaviour of these non-structural elements under seismic loading has been studied in numerous experimental campaigns. However, most of the studies were carried out by means of in-plane tests, while there is a lack of out-of-plane experimental investigations. In this paper, the out-of-plane tests carried out on full scale masonry infilled frames are described. The results of the out-of-plane tests are presented in terms of force-displacement curves and measured out-of-plane displacements. Finally, the reliability of existing analytical approaches developed to estimate the out-of-plane strength of masonry infills is examined on presented experimental results.}, language = {en} } @article{SaretzkiBergmannDahmannetal.2021, author = {Saretzki, Charlotte and Bergmann, Ole and Dahmann, Peter and Janser, Frank and Keimer, Jona and Machado, Patricia and Morrison, Audry and Page, Henry and Pluta, Emil and St{\"u}bing, Felix and K{\"u}pper, Thomas}, title = {Are small airplanes safe with regards to COVID-19 transmission?}, series = {Journal of Travel Medicine}, volume = {28}, journal = {Journal of Travel Medicine}, number = {7}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1708-8305}, doi = {10.1093/jtm/taab105}, year = {2021}, language = {en} } @article{KezerashviliDachwald2021, author = {Kezerashvili, Roman Ya and Dachwald, Bernd}, title = {Preface: Solar sailing: Concepts, technology, and missions II}, series = {Advances in Space Research}, volume = {67}, journal = {Advances in Space Research}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2021.01.037}, pages = {2559 -- 2560}, year = {2021}, language = {en} } @article{HagenkampBlankeDoering2021, author = {Hagenkamp, Markus and Blanke, Tobias and D{\"o}ring, Bernd}, title = {Thermoelectric building temperature control: a potential assessment}, series = {International Journal of Energy and Environmental Engineering}, volume = {13}, journal = {International Journal of Energy and Environmental Engineering}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/s40095-021-00424-x}, pages = {241 -- 254}, year = {2021}, abstract = {This study focuses on thermoelectric elements (TEE) as an alternative for room temperature control. TEE are semi-conductor devices that can provide heating and cooling via a heat pump effect without direct noise emissions and no refrigerant use. An efficiency evaluation of the optimal operating mode is carried out for different numbers of TEE, ambient temperatures, and heating loads. The influence of an additional heat recovery unit on system efficiency and an unevenly distributed heating demand are examined. The results show that TEE can provide heat at a coefficient of performance (COP) greater than one especially for small heating demands and high ambient temperatures. The efficiency increases with the number of elements in the system and is subject to economies of scale. The best COP exceeds six at optimal operating conditions. An additional heat recovery unit proves beneficial for low ambient temperatures and systems with few TEE. It makes COPs above one possible at ambient temperatures below 0 ∘C. The effect increases efficiency by maximal 0.81 (from 1.90 to 2.71) at ambient temperature 5 K below room temperature and heating demand Q˙h=100W but is subject to diseconomies of scale. Thermoelectric technology is a valuable option for electricity-based heat supply and can provide cooling and ventilation functions. A careful system design as well as an additional heat recovery unit significantly benefits the performance. This makes TEE superior to direct current heating systems and competitive to heat pumps for small scale applications with focus on avoiding noise and harmful refrigerants.}, language = {en} } @article{SpietzSproewitzSeefeldtetal.2021, author = {Spietz, Peter and Spr{\"o}witz, Tom and Seefeldt, Patric and Grundmann, Jan Thimo and Jahnke, Rico and Mikschl, Tobias and Mikulz, Eugen and Montenegro, Sergio and Reershemius, Siebo and Renger, Thomas and Ruffer, Michael and Sasaki, Kaname and Sznajder, Maciej and T{\´o}th, Norbert and Ceriotti, Matteo and Dachwald, Bernd and Macdonald, Malcolm and McInnes, Colin and Seboldt, Wolfgang and Quantius, Dominik and Bauer, Waldemar and Wiedemann, Carsten and Grimm, Christian D. and Hercik, David and Ho, Tra-Mi and Lange, Caroline and Schmitz, Nicole}, title = {Paths not taken - The Gossamer roadmap's other options}, series = {Advances in Space Research}, volume = {67}, journal = {Advances in Space Research}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2021.01.044}, pages = {2912 -- 2956}, year = {2021}, language = {en} } @article{AkimbekovDigelAbdievaetal.2021, author = {Akimbekov, Nuraly S. and Digel, Ilya and Abdieva, Gulzhamal and Ualieva, Perizat and Tastambek, Kuanysh}, title = {Lignite biosolubilization and bioconversion by Bacillus sp.: the collation of analytical data}, series = {Biofuels}, volume = {12}, journal = {Biofuels}, number = {3}, publisher = {Taylor \& Francis}, address = {London}, issn = {1759-7277}, pages = {247 -- 258}, year = {2021}, abstract = {The vast metabolic potential of microbes in brown coal (lignite) processing and utilization can greatly contribute to innovative approaches to sustainable production of high-value products from coal. In this study, the multi-faceted and complex coal biosolubilization process by Bacillus sp. RKB 7 isolate from the Kazakhstan coal-mining soil is reported, and the derived products are characterized. Lignite solubilization tests performed for surface and suspension cultures testify to the formation of numerous soluble lignite-derived substances. Almost 24\% of crude lignite (5\% w/v) was solubilized within 14 days under slightly alkaline conditions (pH 8.2). FTIR analysis revealed various functional groups in the obtained biosolubilization products. Analyses of the lignite-derived humic products by UV-Vis and fluorescence spectrometry as well as elemental analysis yielded compatible results indicating the emerging products had a lower molecular weight and degree of aromaticity. Furthermore, XRD and SEM analyses were used to evaluate the biosolubilization processes from mineralogical and microscopic points of view. The findings not only contribute to a deeper understanding of microbe-mineral interactions in coal environments, but also contribute to knowledge of coal biosolubilization and bioconversion with regard to sustainable production of humic substances. The detailed and comprehensive analyses demonstrate the huge biotechnological potential of Bacillus sp. for agricultural productivity and environmental health.}, language = {en} } @article{HeiligersSchoutetensDachwald2021, author = {Heiligers, Jeannette and Schoutetens, Frederic and Dachwald, Bernd}, title = {Photon-sail equilibria in the alpha centauri system}, series = {Journal of Guidance, Control, and Dynamics}, volume = {44}, journal = {Journal of Guidance, Control, and Dynamics}, number = {5}, issn = {1533-3884}, doi = {10.2514/1.G005446}, pages = {1053 -- 1061}, year = {2021}, language = {en} } @article{Bung2021, author = {Bung, Daniel Bernhard}, title = {Extreme flooding in Western Germany: some thoughts on hazards, return periods and risk}, series = {Hydrolink}, journal = {Hydrolink}, number = {4}, publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)}, address = {Madrid}, pages = {108 -- 113}, year = {2021}, abstract = {The low-pressure system Bernd involved extreme rainfalls in the Western part of Germany in July 2021, resulting in major floods, severe damages and a tremendous number of casualties. Such extreme events are rare and full flood protection can never be ensured with reasonable financial means. But still, this event must be starting point to reconsider current design concepts. This article aims at sharing some thoughts on potential hazards, the selection of return periods and remaining risk with the focus on Germany.}, language = {en} } @inproceedings{GrundmannBorellaCeriottietal.2021, author = {Grundmann, Jan Thimo and Borella, Laura and Ceriotti, Matteo and Chand, Suditi and Cordero, Federico and Dachwald, Bernd and Fexer, Sebastian and Grimm, Christian D. and Hendrikse, Jeffrey and Herč{\´i}k, David and Herique, Alain and Hillebrandt, Martin and Ho, Tra-Mi and Kesseler, Lars and Laabs, Martin and Lange, Caroline and Lange, Michael and Lichtenheldt, Roy and McInnes, Colin R. and Moore, Iain and Peloni, Alessandro and Plettenmeier, Dirk and Quantius, Dominik and Seefeldt, Patric and Venditti, Flaviane c. F. and Vergaaij, Merel and Viavattene, Giulia and Virkki, Anne K. and Zander, Martin}, title = {More bucks for the bang: new space solutions, impact tourism and one unique science \& engineering opportunity at T-6 months and counting}, series = {7th IAA Planetary Defense Conference}, booktitle = {7th IAA Planetary Defense Conference}, year = {2021}, abstract = {For now, the Planetary Defense Conference Exercise 2021's incoming fictitious(!), asteroid, 2021 PDC, seems headed for impact on October 20th, 2021, exactly 6 months after its discovery. Today (April 26th, 2021), the impact probability is 5\%, in a steep rise from 1 in 2500 upon discovery six days ago. We all know how these things end. Or do we? Unless somebody kicked off another headline-grabbing media scare or wants to keep civil defense very idle very soon, chances are that it will hit (note: this is an exercise!). Taking stock, it is barely 6 months to impact, a steadily rising likelihood that it will actually happen, and a huge uncertainty of possible impact energies: First estimates range from 1.2 MtTNT to 13 GtTNT, and this is not even the worst-worst case: a 700 m diameter massive NiFe asteroid (covered by a thin veneer of Ryugu-black rubble to match size and brightness), would come in at 70 GtTNT. In down to Earth terms, this could be all between smashing fireworks over some remote area of the globe and a 7.5 km crater downtown somewhere. Considering the deliberate and sedate ways of development of interplanetary missions it seems we can only stand and stare until we know well enough where to tell people to pack up all that can be moved at all and save themselves. But then, it could just as well be a smaller bright rock. The best estimate is 120 m diameter from optical observation alone, by 13\% standard albedo. NASA's upcoming DART mission to binary asteroid (65803) Didymos is designed to hit such a small target, its moonlet Dimorphos. The Deep Impact mission's impactor in 2005 successfully guided itself to the brightest spot on comet 9P/Tempel 1, a relatively small feature on the 6 km nucleus. And 'space' has changed: By the end of this decade, one satellite communication network plans to have launched over 11000 satellites at a pace of 60 per launch every other week. This level of series production is comparable in numbers to the most prolific commercial airliners. Launch vehicle production has not simply increased correspondingly - they can be reused, although in a trade for performance. Optical and radio astronomy as well as planetary radar have made great strides in the past decade, and so has the design and production capability for everyday 'high-tech' products. 60 years ago, spaceflight was invented from scratch within two years, and there are recent examples of fast-paced space projects as well as a drive towards 'responsive space'. It seems it is not quite yet time to abandon all hope. We present what could be done and what is too close to call once thinking is shoved out of the box by a clear and present danger, to show where a little more preparedness or routine would come in handy - or become decisive. And if we fail, let's stand and stare safely and well instrumented anywhere on Earth together in the greatest adventure of science.}, language = {en} } @inproceedings{SchmidtKaschEichleretal.2021, author = {Schmidt, Thomas and Kasch, Susanne and Eichler, Fabian and Thurn, Laura}, title = {Process strategies on laser-based melting of glass powder}, series = {LiM 2021 proceedings}, booktitle = {LiM 2021 proceedings}, pages = {10 Seiten}, year = {2021}, abstract = {This paper presents the laser-based powder bed fusion (L-PBF) using various glass powders (borosilicate and quartz glass). Compared to metals, these require adapted process strategies. First, the glass powders were characterized with regard to their material properties and their processability in the powder bed. This was followed by investigations of the melting behavior of the glass powders with different laser wavelengths (10.6 µm, 1070 nm). In particular, the experimental setup of a CO2 laser was adapted for the processing of glass powder. An experimental setup with integrated coaxial temperature measurement/control and an inductively heatable build platform was created. This allowed the L-PBF process to be carried out at the transformation temperature of the glasses. Furthermore, the component's material quality was analyzed on three-dimensional test specimen with regard to porosity, roughness, density and geometrical accuracy in order to evaluate the developed L-PBF parameters and to open up possible applications.}, language = {en} } @article{BlankeHagenkampDoeringetal.2021, author = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus}, title = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates}, series = {Geothermal Energy}, volume = {9}, journal = {Geothermal Energy}, number = {Article number: 19}, publisher = {Springer}, address = {Berlin}, issn = {2195-9706}, doi = {10.1186/s40517-021-00201-3}, pages = {23 Seiten}, year = {2021}, abstract = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.}, language = {en} } @article{WeldenJablonskiWegeetal.2021, author = {Welden, Rene and Jablonski, Melanie and Wege, Christina and Keusgen, Michael and Wagner, Patrick Hermann and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase}, series = {Biosensors}, volume = {11}, journal = {Biosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2079-6374}, doi = {10.3390/bios11060171}, pages = {Artikel 171}, year = {2021}, abstract = {The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte's pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.}, language = {en} } @inproceedings{MertensPuetzBrauneretal.2021, author = {Mertens, Alexander and P{\"u}tz, Sebastian and Brauner, Philipp and Brillowski, Florian Sascha and Buczak, Nadine and Dammers, Hannah and van Dyck, Marc and Kong, Iris and K{\"o}nigs, Peter and Kortomeikel, Frauke Carole and Rodemann, Niklas and Schaar, Anne Kathrin and Steuer-Dankert, Linda and Wlecke, Shari and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank Thomas and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {Human digital shadow: Data-based modeling of users and usage in the internet of production}, series = {14th Conference Human System Interaction Conference Proceedings}, booktitle = {14th Conference Human System Interaction Conference Proceedings}, publisher = {IEEE}, doi = {10.1109/HSI52170.2021.9538729}, pages = {1 -- 8}, year = {2021}, abstract = {Digital Shadows as the aggregation, linkage and abstraction of data relating to physical objects are a central vision for the future of production. However, the majority of current research takes a technocentric approach, in which the human actors in production play a minor role. Here, the authors present an alternative anthropocentric perspective that highlights the potential and main challenges of extending the concept of Digital Shadows to humans. Following future research methodology, three prospections that illustrate use cases for Human Digital Shadows across organizational and hierarchical levels are developed: human-robot collaboration for manual work, decision support and work organization, as well as human resource management. Potentials and challenges are identified using separate SWOT analyses for the three prospections and common themes are emphasized in a concluding discussion.}, language = {en} } @article{CapitainWagnerHummeletal.2021, author = {Capitain, Charlotte and Wagner, Sebastian and Hummel, Joana and Tippk{\"o}tter, Nils}, title = {Investigation of C-N Formation Between Catechols and Chitosan for the Formation of a Strong, Novel Adhesive Mimicking Mussel Adhesion}, series = {Waste and Biomass Valorization}, volume = {12}, journal = {Waste and Biomass Valorization}, publisher = {Springer Nature}, address = {Cham}, issn = {1877-265X}, doi = {10.1007/s12649-020-01110-5}, pages = {1761 -- 1779}, year = {2021}, language = {en} } @article{GoettenHavermannBraunetal.2021, author = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees}, title = {Aerodynamic Investigations of UAV Sensor Turrets - A Combined Wind-tunnel and CFD Approach}, series = {SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021}, journal = {SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021}, publisher = {AIAA}, address = {Reston, Va.}, doi = {10.2514/6.2021-1535}, pages = {1 -- 12}, year = {2021}, language = {en} } @article{HunkerGossmannRamanetal.2021, author = {Hunker, Jan L. and Gossmann, Matthias and Raman, Aravind Hariharan and Linder, Peter}, title = {Artificial neural networks in cardiac safety assessment: Classification of chemotherapeutic compound effects on hiPSC-derived cardiomyocyte contractility}, series = {Journal of Pharmacological and Toxicological Methods}, volume = {111}, journal = {Journal of Pharmacological and Toxicological Methods}, number = {Article number 107044}, publisher = {Elsevier}, address = {New York}, issn = {1056-8719}, doi = {10.1016/j.vascn.2021.107044}, year = {2021}, language = {en} } @article{JablonskiMuenstermannNorketal.2021, author = {Jablonski, Melanie and M{\"u}nstermann, Felix and Nork, Jasmina and Molinnus, Denise and Muschallik, Lukas and Bongaerts, Johannes and Wagner, Torsten and Keusgen, Michael and Siegert, Petra and Sch{\"o}ning, Michael Josef}, title = {Capacitive field-effect biosensor applied for the detection of acetoin in alcoholic beverages and fermentation broths}, series = {physica status solidi (a) applications and materials science}, volume = {218}, journal = {physica status solidi (a) applications and materials science}, number = {13}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.202000765}, pages = {7 Seiten}, year = {2021}, abstract = {An acetoin biosensor based on a capacitive electrolyte-insulator-semiconductor (EIS) structure modified with the enzyme acetoin reductase, also known as butane-2,3-diol dehydrogenase (Bacillus clausii DSM 8716ᵀ), is applied for acetoin detection in beer, red wine, and fermentation broth samples for the first time. The EIS sensor consists of an Al/p-Si/SiO₂/Ta₂O₅ layer structure with immobilized acetoin reductase on top of the Ta₂O₅ transducer layer by means of crosslinking via glutaraldehyde. The unmodified and enzyme-modified sensors are electrochemically characterized by means of leakage current, capacitance-voltage, and constant capacitance methods, respectively.}, language = {en} } @article{GoettenFingerHavermannetal.2021, author = {G{\"o}tten, Falk and Finger, Felix and Havermann, Marc and Braun, Carsten and Marino, M. and Bil, C.}, title = {Full configuration drag estimation of short-to-medium range fixed-wing UAVs and its impact on initial sizing optimization}, series = {CEAS Aeronautical Journal}, volume = {12}, journal = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Berlin}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-021-00522-w}, pages = {589 -- 603}, year = {2021}, abstract = {The paper presents the derivation of a new equivalent skin friction coefficient for estimating the parasitic drag of short-to-medium range fixed-wing unmanned aircraft. The new coefficient is derived from an aerodynamic analysis of ten different unmanned aircraft used for surveillance, reconnaissance, and search and rescue missions. The aircraft is simulated using a validated unsteady Reynolds-averaged Navier Stokes approach. The UAV's parasitic drag is significantly influenced by the presence of miscellaneous components like fixed landing gears or electro-optical sensor turrets. These components are responsible for almost half of an unmanned aircraft's total parasitic drag. The new equivalent skin friction coefficient accounts for these effects and is significantly higher compared to other aircraft categories. It is used to initially size an unmanned aircraft for a typical reconnaissance mission. The improved parasitic drag estimation yields a much heavier unmanned aircraft when compared to the sizing results using available drag data of manned aircraft.}, language = {en} } @inproceedings{NeumannAdamBackesetal.2021, author = {Neumann, Hannah and Adam, Mario and Backes, Klaus and B{\"o}rner, Martin and Clees, Tanja and Doetsch, Christian and Glaeser, Susanne and Herrmann, Ulf and May, Johanna and Rosenthal, Florian and Sauer, Dirk Uwe and Stadler, Ingo}, title = {Development of open educational resources for renewable energy and the energy transition process}, series = {ISES SWC 2021}, booktitle = {ISES SWC 2021}, publisher = {International Solar Energy Society}, address = {Freiburg}, doi = {10.18086/swc.2021.47.03}, pages = {6 Seiten}, year = {2021}, abstract = {The dissemination of knowledge about renewable energies is understood as a social task with the highest topicality. The transfer of teaching content on renewable energies into digital open educational resources offers the opportunity to significantly accelerate the implementation of the energy transition. Thus, in the here presented project six German universities create open educational resources for the energy transition. These materials are available to the public on the internet under a free license. So far there has been no publicly accessible, editable media that cover entire learning units about renewable energies extensively and in high technical quality. Thus, in this project, the content that remains up-to-date for a longer period is appropriately prepared in terms of media didactics. The materials enable lecturers to provide students with in-depth training about technologies for the energy transition. In a particular way, the created material is also suitable for making the general public knowledgeable about the energy transition with scientifically based material.}, language = {en} } @article{HeuermannHarzheimCronenbroeck2021, author = {Heuermann, Holger and Harzheim, Thomas and Cronenbroeck, Tobias}, title = {First SIMO harmonic radar based on the SFCW concept and the HR transfer function}, series = {Remote sensing}, volume = {13}, journal = {Remote sensing}, number = {24}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs13245088}, pages = {23 Seiten}, year = {2021}, abstract = {This paper presents a new SIMO radar system based on a harmonic radar (HR) stepped frequency continuous wave (SFCW) architecture. Simple tags that can be electronically individually activated and deactivated via a DC control voltage were developed and combined to form an MO array field. This HR operates in the entire 2.45 GHz ISM band for transmitting the illumination signal and receives at twice the stimulus frequency and bandwidth centered around 4.9 GHz. This paper presents the development, the basic theory of a HR system for the characterization of objects placed into the propagation path in-between the radar and the reflectors (similar to a free-space measurement with a network analyzer) as well as first measurements performed by the system. Further detailed measurement series will be made available later on to other researchers to develop AI and machine learning based signal processing routines or synthetic aperture radar algorithms for imaging, object recognition, and feature extraction. For this purpose, the necessary information is published in this paper. It is explained in detail why this SIMO-HR can be an attractive solution augmenting or replacing existing systems for radar measurements in production technology for material under test measurements and as a simplified MIMO system. The novel HR transfer function, which is a basis for researchers and developers for material characterization or imaging algorithms, is introduced and metrologically verified in a well traceable coaxial setup.}, language = {en} } @article{ErpicumCrookstonBombardellietal.2021, author = {Erpicum, Sebastien and Crookston, Brian M. and Bombardelli, Fabian and Bung, Daniel Bernhard and Felder, Stefan and Mulligan, Sean and Oertel, Mario and Palermo, Michele}, title = {Hydraulic structures engineering: An evolving science in a changing world}, series = {Wires Water}, volume = {8}, journal = {Wires Water}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {2049-1948}, doi = {10.1002/wat2.1505}, year = {2021}, language = {en} } @inproceedings{MilkovaButenwegDumovaJovanoska2021, author = {Milkova, Kristina and Butenweg, Christoph and Dumova-Jovanoska, Elena}, title = {Region-sensitive comprehensive procedure for determination of seismic fragility curves}, series = {1st Croatian Conference on Earthquake Engineering 1CroCEE}, booktitle = {1st Croatian Conference on Earthquake Engineering 1CroCEE}, publisher = {University of Zagreb}, address = {Zagreb}, doi = {10.5592/CO/1CroCEE.2021.158}, pages = {121 -- 128}, year = {2021}, abstract = {Seismic vulnerability estimation of existing structures is unquestionably interesting topic of high priority, particularly after earthquake events. Having in mind the vast number of old masonry buildings in North Macedonia serving as public institutions, it is evident that the structural assessment of these buildings is an issue of great importance. In this paper, a comprehensive methodology for the development of seismic fragility curves of existing masonry buildings is presented. A scenario - based method that incorporates the knowledge of the tectonic style of the considered region, the active fault characterization, the earth crust model and the historical seismicity (determined via the Neo Deterministic approach) is used for calculation of the necessary response spectra. The capacity of the investigated masonry buildings has been determined by using nonlinear static analysis. MINEA software (SDA Engineering) is used for verification of the structural safety of the structures Performance point, obtained from the intersection of the capacity of the building and the spectra used, is selected as a response parameter. The thresholds of the spectral displacement are obtained by splitting the capacity curve into five parts, utilizing empirical formulas which are represented as a function of yield displacement and ultimate displacement. As a result, four levels of damage limit states are determined. A maximum likelihood estimation procedure for the process of fragility curves determination is noted as a final step in the proposed procedure. As a result, region specific series of vulnerability curves for structures are defined.}, language = {en} } @inproceedings{BalaskasHoffmeisterButenwegetal.2021, author = {Balaskas, Georgios and Hoffmeister, Benno and Butenweg, Christoph and Pilz, Marco and Bauer, Anna}, title = {Earthquake early warning and response system based on intelligent seismic and monitoring sensors embedded in a communication platform and coupled with BIM models}, series = {Proceedings of COMPDYN 2021}, booktitle = {Proceedings of COMPDYN 2021}, editor = {Papadrakakis, Manolis and Fragiadakis, Michalis}, publisher = {National Technical University of Athens}, address = {Athen}, isbn = {978-618-85072-5-8}, issn = {2623-3347}, doi = {10.7712/120121.8539.18855}, pages = {987 -- 998}, year = {2021}, abstract = {This paper describes the concept of an innovative, interdisciplinary, user-oriented earthquake warning and rapid response system coupled with a structural health monitoring system (SHM), capable to detect structural damages in real time. The novel system is based on interconnected decentralized seismic and structural health monitoring sensors. It is developed and will be exemplarily applied on critical infrastructures in Lower Rhine Region, in particular on a road bridge and within a chemical industrial facility. A communication network is responsible to exchange information between sensors and forward warnings and status reports about infrastructures'health condition to the concerned recipients (e.g., facility operators, local authorities). Safety measures such as emergency shutdowns are activated to mitigate structural damages and damage propagation. Local monitoring systems of the infrastructures are integrated in BIM models. The visualization of sensor data and the graphic representation of the detected damages provide spatial content to sensors data and serve as a useful and effective tool for the decision-making processes after an earthquake in the region under consideration.}, language = {en} } @inproceedings{ŠakićMilijašMarinkovićetal.2021, author = {Šakić, Bogdan and Milijaš, Aleksa and Marinković, Marko and Butenweg, Christoph and Klinkel, Sven}, title = {Influence of prior in-plane damage on the out-of-plane response of non-load bearing unreinforced masonry walls under seismic load}, series = {Proceedings of COMPDYN 2021}, booktitle = {Proceedings of COMPDYN 2021}, editor = {Papadrakakis, Manolis and Fragiadakis, Michalis}, publisher = {National Technical University of Athens}, address = {Athen}, isbn = {9786188507258}, issn = {2623-3347}, doi = {10.7712/120121.8527.18913}, pages = {808 -- 828}, year = {2021}, abstract = {Reinforced concrete frames with masonry infill walls are popular form of construction all over the world as well in seismic regions. While severe earthquakes can cause high level of damage of both reinforced concrete and masonry infills, earthquakes of lower to medium intensity some-times can cause significant level of damage of masonry infill walls. Especially important is the level of damage of face loaded infill masonry walls (out-of-plane direction) as out-of-plane load cannot only bring high level of damage to the wall, it can also be life-threating for the people near the wall. The response in out-of-plane direction directly depends on the prior in-plane damage, as previous investigation shown that it decreases resistance capacity of the in-fills. Behaviour of infill masonry walls with and without prior in-plane load is investigated in the experimental campaign and the results are presented in this paper. These results are later compared with analytical approaches for the out-of-plane resistance from the literature. Conclusions based on the experimental campaign on the influence of prior in-plane damage on the out-of-plane response of infill walls are compared with the conclusions from other authors who investigated the same problematic.}, language = {en} } @article{Kleefeld2021, author = {Kleefeld, Andreas}, title = {The hot spots conjecture can be false: some numerical examples}, series = {Advances in Computational Mathematics}, volume = {47}, journal = {Advances in Computational Mathematics}, publisher = {Springer}, address = {Dordrecht}, issn = {1019-7168}, doi = {10.1007/s10444-021-09911-5}, year = {2021}, abstract = {The hot spots conjecture is only known to be true for special geometries. This paper shows numerically that the hot spots conjecture can fail to be true for easy to construct bounded domains with one hole. The underlying eigenvalue problem for the Laplace equation with Neumann boundary condition is solved with boundary integral equations yielding a non-linear eigenvalue problem. Its discretization via the boundary element collocation method in combination with the algorithm by Beyn yields highly accurate results both for the first non-zero eigenvalue and its corresponding eigenfunction which is due to superconvergence. Additionally, it can be shown numerically that the ratio between the maximal/minimal value inside the domain and its maximal/minimal value on the boundary can be larger than 1 + 10- 3. Finally, numerical examples for easy to construct domains with up to five holes are provided which fail the hot spots conjecture as well.}, language = {en} } @article{ButenwegBursiPaolaccietal.2021, author = {Butenweg, Christoph and Bursi, Oreste S. and Paolacci, Fabrizio and Marinković, Marko and Lanese, Igor and Nardin, Chiara and Quinci, Gianluca}, title = {Seismic performance of an industrial multi-storey frame structure with process equipment subjected to shake table testing}, series = {Engineering Structures}, volume = {243}, journal = {Engineering Structures}, number = {15}, editor = {Yang, J.}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0141-0296}, doi = {10.1016/j.engstruct.2021.112681}, year = {2021}, abstract = {Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of process equipment and multiple and simultaneous release of hazardous substances. Nonetheless, current standards for seismic design of industrial facilities are considered inadequate to guarantee proper safety conditions against exceptional events entailing loss of containment and related consequences. On these premises, the SPIF project -Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities- was proposed within the framework of the European H2020 SERA funding scheme. In detail, the objective of the SPIF project is the investigation of the seismic behaviour of a representative industrial multi-storey frame structure equipped with complex process components by means of shaking table tests. Along this main vein and in a performance-based design perspective, the issues investigated in depth are the interaction between a primary moment resisting frame (MRF) steel structure and secondary process components that influence the performance of the whole system; and a proper check of floor spectra predictions. The evaluation of experimental data clearly shows a favourable performance of the MRF structure, some weaknesses of local details due to the interaction between floor crossbeams and process components and, finally, the overconservatism of current design standards w.r.t. floor spectra predictions.}, language = {en} } @inproceedings{TranStaat2021, author = {Tran, Ngoc Trinh and Staat, Manfred}, title = {FEM shakedown analysis of Kirchhoff-Love plates under uncertainty of strength}, series = {Proceedings of UNCECOMP 2021}, booktitle = {Proceedings of UNCECOMP 2021}, isbn = {978-618-85072-6-5}, doi = {10.7712/120221.8041.19047}, pages = {323 -- 338}, year = {2021}, abstract = {A new formulation to calculate the shakedown limit load of Kirchhoff plates under stochastic conditions of strength is developed. Direct structural reliability design by chance con-strained programming is based on the prescribed failure probabilities, which is an effective approach of stochastic programming if it can be formulated as an equivalent deterministic optimization problem. We restrict uncertainty to strength, the loading is still deterministic. A new formulation is derived in case of random strength with lognormal distribution. Upper bound and lower bound shakedown load factors are calculated simultaneously by a dual algorithm.}, language = {en} } @article{HacklNacovKammerlohretal.2021, author = {Hackl, Michael and Nacov, Julia and Kammerlohr, Sandra and Staat, Manfred and Buess, Eduard and Leschinger, Tim and M{\"u}ller, Lars P. and Wegmann, Kilian}, title = {Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure}, series = {The American Journal of Sports Medicine}, volume = {49}, journal = {The American Journal of Sports Medicine}, number = {7}, publisher = {Sage}, address = {London}, issn = {1552-3365}, doi = {10.1177/03635465211006138}, pages = {1847 -- 1853}, year = {2021}, language = {en} } @inproceedings{SchoutetensDachwaldHeiligers2021, author = {Schoutetens, Frederic and Dachwald, Bernd and Heiligers, Jeannette}, title = {Optimisation of photon-sail trajectories in the alpha-centauri system using evolutionary neurocontrol}, series = {8th ICATT 2021}, booktitle = {8th ICATT 2021}, pages = {1 -- 15}, year = {2021}, abstract = {With the increased interest for interstellar exploration after the discovery of exoplanets and the proposal by Breakthrough Starshot, this paper investigates the optimisation of photon-sail trajectories in Alpha Centauri. The prime objective is to find the optimal steering strategy for a photonic sail to get captured around one of the stars after a minimum-time transfer from Earth. By extending the idea of the Breakthrough Starshot project with a deceleration phase upon arrival, the mission's scientific yield will be increased. As a secondary objective, transfer trajectories between the stars and orbit-raising manoeuvres to explore the habitable zones of the stars are investigated. All trajectories are optimised for minimum time of flight using the trajectory optimisation software InTrance. Depending on the sail technology, interstellar travel times of 77.6-18,790 years can be achieved, which presents an average improvement of 30\% with respect to previous work. Still, significant technological development is required to reach and be captured in the Alpha-Centauri system in less than a century. Therefore, a fly-through mission arguably remains the only option for a first exploratory mission to Alpha Centauri, but the enticing results obtained in this work provide perspective for future long-residence missions to our closest neighbouring star system.}, language = {en} } @article{TranStaat2021, author = {Tran, Ngoc Trinh and Staat, Manfred}, title = {Direct plastic structural design under random strength and random load by chance constrained programming}, series = {European Journal of Mechanics - A/Solids}, volume = {85}, journal = {European Journal of Mechanics - A/Solids}, number = {Article 104106}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0997-7538}, doi = {10.1016/j.euromechsol.2020.104106}, year = {2021}, language = {en} } @inproceedings{HandschuhStollenwerkBorchert2021, author = {Handschuh, Nils and Stollenwerk, Dominik and Borchert, J{\"o}rg}, title = {Operation of thermal storage power plants under high renewable grid penetration}, series = {NEIS 2021: Conference on Sustainable Energy Supply and Energy Storage Systems}, booktitle = {NEIS 2021: Conference on Sustainable Energy Supply and Energy Storage Systems}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-5651-3}, pages = {261 -- 265}, year = {2021}, abstract = {The planned coal phase-out in Germany by 2038 will lead to the dismantling of power plants with a total capacity of approx. 30 GW. A possible further use of these assets is the conversion of the power plants to thermal storage power plants; the use of these power plants on the day-ahead market is considerably limited by their technical parameters. In this paper, the influence of the technical boundary conditions on the operating times of these storage facilities is presented. For this purpose, the storage power plants were described as an MILP problem and two price curves, one from 2015 with a relatively low renewable penetration (33 \%) and one from 2020 with a high renewable energy penetration (51 \%) are compared. The operating times were examined as a function of the technical parameters and the critical influencing factors were investigated. The thermal storage power plant operation duration and the energy shifted with the price curve of 2020 increases by more than 25 \% compared to 2015.}, language = {en} } @article{FaganBitzBjoerkmanBurtscheretal.2021, author = {Fagan, Andrew J. and Bitz, Andreas and Bj{\"o}rkman-Burtscher, Isabella M. and Collins, Christopher M. and Kimbrell, Vera and Raaijmakers, Alexander J. E.}, title = {7T MR Safety}, series = {Journal of Magnetic Resonance Imaging (JMRI)}, volume = {53}, journal = {Journal of Magnetic Resonance Imaging (JMRI)}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2586}, doi = {10.1002/jmri.27319}, pages = {333 -- 346}, year = {2021}, language = {en} } @article{MeyerGranrathFeyerletal.2021, author = {Meyer, Max-Arno and Granrath, Christian and Feyerl, G{\"u}nter and Richenhagen, Johannes and Kaths, Jakob and Andert, Jakob}, title = {Closed-loop platoon simulation with cooperative intelligent transportation systems based on vehicle-to-X communication}, series = {Simulation Modelling Practice and Theory}, volume = {106}, journal = {Simulation Modelling Practice and Theory}, number = {Art. 102173}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1569-190X}, doi = {10.1016/j.simpat.2020.102173}, year = {2021}, language = {en} } @article{SerrorHackHenzeetal.2021, author = {Serror, Martin and Hack, Sacha and Henze, Martin and Schuba, Marko and Wehrle, Klaus}, title = {Challenges and Opportunities in Securing the Industrial Internet of Things}, series = {IEEE Transactions on Industrial Informatics}, volume = {17}, journal = {IEEE Transactions on Industrial Informatics}, number = {5}, publisher = {IEEE}, address = {New York}, issn = {1941-0050}, doi = {10.1109/TII.2020.3023507}, pages = {2985 -- 2996}, year = {2021}, language = {en} } @article{BerneckerBoyerGathmann2021, author = {Bernecker, Andreas and Boyer, Pierre C. and Gathmann, Christina}, title = {The Role of Electoral Incentives for Policy Innovation: Evidence from the US Welfare Reform}, series = {American Economic Journal: Economic Policy}, volume = {13}, journal = {American Economic Journal: Economic Policy}, number = {2}, publisher = {American Economic Association}, address = {Nashville, Tenn.}, issn = {1945-774X}, doi = {10.1257/pol.20190690}, pages = {26 -- 57}, year = {2021}, language = {en} } @inproceedings{HoegenDonckerBragardetal.2021, author = {Hoegen, Anne von and Doncker, Rik W. De and Bragard, Michael and Hoegen, Svenja von}, title = {Problem-based learning in automation engineering: performing a remote laboratory aession aerving various educational attainments}, series = {2021 IEEE Global Engineering Education Conference (EDUCON)}, booktitle = {2021 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1109/EDUCON46332.2021.9453925}, pages = {1605 -- 1614}, year = {2021}, abstract = {During the Covid-19 pandemic, vocational colleges, universities of applied science and technical universities often had to cancel laboratory sessions requiring students' attendance. These above of all are of decisive importance in order to give learners an understanding of theory through practical work.This paper is a contribution to the implementation of distance learning for laboratory work applicable for several upper secondary educational facilities. Its aim is to provide a paradigm for hybrid teaching to analyze and control a non-linear system depicted by a tank model. For this reason, we redesign a full series of laboratory sessions on the basis of various challenges. Thus, it is suitable to serve different reference levels of the European Qualifications Framework (EQF).We present problem-based learning through online platforms to compensate the lack of a laboratory learning environment. With a task deduced from their future profession, we give students the opportunity to develop own solutions in self-defined time intervals. A requirements specification provides the framework conditions in terms of time and content for students having to deal with the challenges of the project in a self-organized manner with regard to inhomogeneous previous knowledge. If the concept of Complete Action is introduced in classes before, they will automatically apply it while executing the project.The goal is to combine students' scientific understanding with a procedural knowledge. We suggest a series of remote laboratory sessions that combine a problem formulation from the subject area of Measurement, Control and Automation Technology with a project assignment that is common in industry by providing extracts from a requirements specification.}, language = {en} } @inproceedings{HueningStuettgen2021, author = {H{\"u}ning, Felix and St{\"u}ttgen, Marcel}, title = {Work in Progress: Interdisciplinary projects in times of COVID-19 crisis - challenges, risks and chances}, series = {2021 IEEE Global Engineering Education Conference (EDUCON)}, booktitle = {2021 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1109/EDUCON46332.2021.9454006}, pages = {1175 -- 1179}, year = {2021}, abstract = {Project work and inter disciplinarity are integral parts of today's engineering work. It is therefore important to incorporate these aspects into the curriculum of academic studies of engineering. At the faculty of Electrical Engineering and Information Technology an interdisciplinary project is part of the bachelor program to address these topics. Since the summer term 2020 most courses changed to online mode during the Covid-19 crisis including the interdisciplinary projects. This online mode introduces additional challenges to the execution of the projects, both for the students as well as for the lecture. The challenges, but also the risks and chances of this kind of project courses are subject of this paper, based on five different interdisciplinary projects}, language = {en} } @article{HugenrothBorchardtRitteretal.2021, author = {Hugenroth, Kristin and Borchardt, Ralf and Ritter, Philine and Groß‑Hardt, Sascha and Meyns, Bart and Verbelen, Tom and Steinseifer, Ulrich and Kaufmann, Tim A. S. and Engelmann, Ulrich M.}, title = {Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, number = {Art. No. 16800}, publisher = {Springer}, address = {Berlin}, issn = {2045-2322}, doi = {10.1038/s41598-021-96397-2}, pages = {1 -- 12}, year = {2021}, abstract = {Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5\% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6\%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.}, language = {en} } @inproceedings{MerkensHebel2021, author = {Merkens, Torsten and Hebel, Christoph}, title = {Sharing mobility concepts - flexible, sustainable, smart}, series = {Proceedings of the 1st UNITED - Southeast Asia Automotive Interest Group (SAIG) International Conference}, booktitle = {Proceedings of the 1st UNITED - Southeast Asia Automotive Interest Group (SAIG) International Conference}, isbn = {978-3-902103-94-9}, pages = {43 -- 44}, year = {2021}, language = {en} } @article{BrockhausBehbahaniMurisetal.2021, author = {Brockhaus, Moritz K. and Behbahani, Mehdi and Muris, Farina and Jansen, Sebastian V. and Schmitz- Rode, Thomas and Steinseifer, Ulrich and Clauser, Johanna C.}, title = {In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept}, series = {Artificial Organs}, volume = {45}, journal = {Artificial Organs}, number = {12}, publisher = {Wiley}, address = {Weinheim}, issn = {1525-1594}, doi = {10.1111/aor.14046}, pages = {1513 -- 1521}, year = {2021}, abstract = {Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6\% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential.}, language = {en} } @inproceedings{OlderogMohrBegingetal.2021, author = {Olderog, M. and Mohr, P. and Beging, Stefan and Tsoumpas, C. and Ziemons, Karl}, title = {Simulation study on the role of tissue-scattered events in improving sensitivity for a compact time of flight compton positron emission tomograph}, series = {2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)}, booktitle = {2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)}, publisher = {IEEE}, address = {New York, NY}, isbn = {978-1-7281-7693-2}, doi = {10.1109/NSS/MIC42677.2020.9507901}, pages = {4 Seiten}, year = {2021}, abstract = {In positron emission tomography improving time, energy and spatial detector resolutions and using Compton kinematics introduces the possibility to reconstruct a radioactivity distribution image from scatter coincidences, thereby enhancing image quality. The number of single scattered coincidences alone is in the same order of magnitude as true coincidences. In this work, a compact Compton camera module based on monolithic scintillation material is investigated as a detector ring module. The detector interactions are simulated with Monte Carlo package GATE. The scattering angle inside the tissue is derived from the energy of the scattered photon, which results in a set of possible scattering trajectories or broken line of response. The Compton kinematics collimation reduces the number of solutions. Additionally, the time of flight information helps localize the position of the annihilation. One of the questions of this investigation is related to how the energy, spatial and temporal resolutions help confine the possible annihilation volume. A comparison of currently technically feasible detector resolutions (under laboratory conditions) demonstrates the influence on this annihilation volume and shows that energy and coincidence time resolution have a significant impact. An enhancement of the latter from 400 ps to 100 ps leads to a smaller annihilation volume of around 50\%, while a change of the energy resolution in the absorber layer from 12\% to 4.5\% results in a reduction of 60\%. The inclusion of single tissue-scattered data has the potential to increase the sensitivity of a scanner by a factor of 2 to 3 times. The concept can be further optimized and extended for multiple scatter coincidences and subsequently validated by a reconstruction algorithm.}, language = {en} } @inproceedings{UlmerBraunChengetal.2021, author = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Adapting augmented reality systems to the users' needs using gamification and error solving methods}, series = {Procedia CIRP - 54th CIRP CMS 2021 - Towards Digitalized Manufacturing 4.0}, volume = {104}, booktitle = {Procedia CIRP - 54th CIRP CMS 2021 - Towards Digitalized Manufacturing 4.0}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2021.11.024}, pages = {140 -- 145}, year = {2021}, abstract = {Animations of virtual items in AR support systems are typically predefined and lack interactions with dynamic physical environments. AR applications rarely consider users' preferences and do not provide customized spontaneous support under unknown situations. This research focuses on developing adaptive, error-tolerant AR systems based on directed acyclic graphs and error resolving strategies. Using this approach, users will have more freedom of choice during AR supported work, which leads to more efficient workflows. Error correction methods based on CAD models and predefined process data create individual support possibilities. The framework is implemented in the Industry 4.0 model factory at FH Aachen.}, language = {en} } @inproceedings{Huening2021, author = {H{\"u}ning, Felix}, title = {Sustainable changes beyond covid-19 for a second semester physics course for electrical engineering students}, series = {Blended Learning in Engineering Education: challenging, enlightening - and lasting?}, booktitle = {Blended Learning in Engineering Education: challenging, enlightening - and lasting?}, isbn = {978-2-87352-023-6}, pages = {1424 -- 1428}, year = {2021}, abstract = {The course Physics for Electrical Engineering is part of the curriculum of the bachelor program Electrical Engineering at University of Applied Science Aachen. Before covid-19 the course was conducted in a rather traditional way with all parts (lecture, exercise and lab) face-to-face. This teaching approach changed fundamentally within a week when the covid-19 limitations forced all courses to distance learning. All parts of the course were transformed to pure distance learning including synchronous and asynchronous parts for the lecture, live online-sessions for the exercises and self-paced labs at home. Using these methods, the course was able to impart the required knowledge and competencies. Taking the teacher's observations of the student's learning behaviour and engagement, the formal and informal feedback of the students and the results of the exams into account, the new methods are evaluated with respect to effectiveness, sustainability and suitability for competence transfer. Based on this analysis strong and weak points of the concept and countermeasures to solve the weak points were identified. The analysis further leads to a sustainable teaching approach combining synchronous and asynchronous parts with self-paced learning times that can be used in a very flexible manner for different learning scenarios, pure online, hybrid (mixture of online and presence times) and pure presence teaching.}, language = {en} } @article{LeiseEsserEichenlaubetal.2021, author = {Leise, Philipp and Eßer, Arved and Eichenlaub, Tobias and Schleiffer, Jean-Eric and Altherr, Lena and Rinderknecht, Stephan and Pelz, Peter F.}, title = {Sustainable system design of electric powertrains - comparison of optimization methods}, series = {Engineering Optimization}, journal = {Engineering Optimization}, publisher = {Taylor \& Francis}, address = {London}, issn = {0305-215X}, doi = {10.1080/0305215X.2021.1928660}, year = {2021}, abstract = {The transition within transportation towards battery electric vehicles can lead to a more sustainable future. To account for the development goal 'climate action' stated by the United Nations, it is mandatory, within the conceptual design phase, to derive energy-efficient system designs. One barrier is the uncertainty of the driving behaviour within the usage phase. This uncertainty is often addressed by using a stochastic synthesis process to derive representative driving cycles and by using cycle-based optimization. To deal with this uncertainty, a new approach based on a stochastic optimization program is presented. This leads to an optimization model that is solved with an exact solver. It is compared to a system design approach based on driving cycles and a genetic algorithm solver. Both approaches are applied to find efficient electric powertrains with fixed-speed and multi-speed transmissions. Hence, the similarities, differences and respective advantages of each optimization procedure are discussed.}, language = {en} } @article{GrundlachBaumannEngelmann2021, author = {Grundlach, Michael and Baumann, Martin and Engelmann, Ulrich M.}, title = {How Multimodal Examinations Can Increase Sustainable Student Gain by Aligning Teaching and Assessment}, series = {Current Directions in Biomedical Engineering}, volume = {7}, journal = {Current Directions in Biomedical Engineering}, number = {7/2}, editor = {D{\"o}ssel, Olaf}, publisher = {De Gruyter}, address = {Berlin}, isbn = {2364-5504}, doi = {10.1515/cdbme-2021-2019}, pages = {73 -- 76}, year = {2021}, abstract = {Modern industry and multi-discipline projects require highly trained individuals with resilient science and engineering back-grounds. Graduates must be able to agilely apply excellent theoretical knowledge in their subject matter as well as essential practical "hands-on" knowledge of diverse working processes to solve complex problems. To meet these demands, university education follows the concept of Constructive Alignment and thus increasingly adopts the teaching of necessary practical skills to the actual industry requirements and assessment routines. However, a systematic approach to coherently align these three central teaching demands is strangely absent from current university curricula. We demonstrate the feasibility of implementing practical assessments in a regular theory-based examination, thus defining the term "blended assessment". We assessed a course for natural science and engineering students pursuing a career in biomedical engineering, and evaluated the benefit of blended assessment exams for students and lecturers. Our controlled study assessed the physiological background of electrocardiograms (ECGs), the practical measurement of ECG curves, and their interpretation of basic pathologic alterations. To study on long time effects, students have been assessed on the topic twice with a time lag of 6 months. Our findings suggest a significant improvement in student gain with respect to practical skills and theoretical knowledge. The results of the reassessments support these outcomes. From the lecturers' point of view, blended assessment complements practical training courses while keeping organizational effort manageable. We consider blended assessment a viable tool for providing an improved student gain, industry-ready education format that should be evaluated and established further to prepare university graduates optimally for their future careers.}, language = {en} } @inproceedings{KernImaniVashianiTimmermanns2021, author = {Kern, Alexander and Imani Vashiani, Anahita and Timmermanns, Tobias}, title = {Threat for human beings due to touch voltages and body currents caused by direct lightning strikes in case of non-isolated lightning protection systems using natural components}, series = {35th International Conference on Lightning Protection (ICLP) and XVI International Symposium on Lightning Protection (SIPDA)}, booktitle = {35th International Conference on Lightning Protection (ICLP) and XVI International Symposium on Lightning Protection (SIPDA)}, publisher = {IEEE}, address = {New York, NY}, isbn = {978-1-6654-2346-5}, doi = {10.1109/ICLPandSIPDA54065.2021.9627465}, pages = {8 Seiten}, year = {2021}, abstract = {For typical cases of non-isolated lightning protection systems (LPS) the impulse currents are investigated which may flow through a human body directly touching a structural part of the LPS. Based on a basic LPS model with conventional down-conductors especially the cases of external and internal steel columns and metal fa{\c{c}}ades are considered and compared. Numerical simulations of the line quantities voltages and currents in the time domain are performed with an equivalent circuit of the entire LPS. As a result it can be stated that by increasing the number of conventional down-conductors and external steel columns the threat for a human being can indeed be reduced, but not down to an acceptable limit. In case of internal steel columns used as natural down-conductors the threat can be reduced sufficiently, depending on the low-resistive connection of the steel columns to the lightning equipotential bonding or the earth termination system, resp. If a metal fa{\c{c}}ade is used the threat for human beings touching is usually very low, if the fa{\c{c}}ade is sufficiently interconnected and multiply connected to the lightning equipotential bonding or the earth termination system, resp.}, language = {en} } @book{Pieper2021, author = {Pieper, Martin}, title = {Quantum mechanics: Introduction to mathematical formulation}, publisher = {Springer}, address = {Wiesbaden}, isbn = {978-3-658-32644-9}, doi = {10.1007/978-3-658-32645-6}, pages = {XIII, 33}, year = {2021}, abstract = {Anyone who has always wanted to understand the hieroglyphs on Sheldon's blackboard in the TV series The Big Bang Theory or who wanted to know exactly what the fate of Schr{\"o}dinger's cat is all about will find a short, descriptive introduction to the world of quantum mechanics in this essential. The text particularly focuses on the mathematical description in the Hilbert space. The content goes beyond popular scientific presentations, but is nevertheless suitable for readers without special prior knowledge thanks to the clear examples.}, language = {en} } @inproceedings{EnglhardWeberArent2021, author = {Englhard, Markus and Weber, Tobias and Arent, Jan-Christoph}, title = {Efficiency enhancement for CFRP-Prepregautoclave manufacturing by means of simulation-assisted loading optimization}, series = {Proceedings of SAMPE Europe Conference 2021}, booktitle = {Proceedings of SAMPE Europe Conference 2021}, pages = {8 Seiten}, year = {2021}, abstract = {A new method for improved autoclave loading within the restrictive framework of helicopter manufacturing is proposed. It is derived from experimental and numerical studies of the curing process and aims at optimizing tooling positions in the autoclave for fast and homogeneous heat-up. The mold positioning is based on two sets of information. The thermal properties of the molds, which can be determined via semi-empirical thermal simulation. The second information is a previously determined distribution of heat transfer coefficients inside the autoclave. Finally, an experimental proof of concept is performed to show a cycle time reduction of up to 31\% using the proposed methodology.}, language = {en} } @article{EngemannCoenenDawaretal.2021, author = {Engemann, Heiko and C{\"o}nen, Patrick and Dawar, Harshal and Du, Shengzhi and Kallweit, Stephan}, title = {A robot-assisted large-scale inspection of wind turbine blades in manufacturing using an autonomous mobile manipulator}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app11199271}, pages = {1 -- 22}, year = {2021}, abstract = {Wind energy represents the dominant share of renewable energies. The rotor blades of a wind turbine are typically made from composite material, which withstands high forces during rotation. The huge dimensions of the rotor blades complicate the inspection processes in manufacturing. The automation of inspection processes has a great potential to increase the overall productivity and to create a consistent reliable database for each individual rotor blade. The focus of this paper is set on the process of rotor blade inspection automation by utilizing an autonomous mobile manipulator. The main innovations include a novel path planning strategy for zone-based navigation, which enables an intuitive right-hand or left-hand driving behavior in a shared human-robot workspace. In addition, we introduce a new method for surface orthogonal motion planning in connection with large-scale structures. An overall execution strategy controls the navigation and manipulation processes of the long-running inspection task. The implemented concepts are evaluated in simulation and applied in a real-use case including the tip of a rotor blade form.}, language = {en} } @incollection{AltherrLeise2021, author = {Altherr, Lena and Leise, Philipp}, title = {Resilience as a concept for mastering uncertainty}, series = {Mastering Uncertainty in Mechanical Engineering}, booktitle = {Mastering Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78353-2}, doi = {10.1007/978-3-030-78354-9}, pages = {412 -- 417}, year = {2021}, language = {en} } @incollection{AltherrLeisePfetschetal.2021, author = {Altherr, Lena and Leise, Philipp and Pfetsch, Marc E. and Schmitt, Andreas}, title = {Optimal design of resilient technical systems on the example of water supply systems}, series = {Mastering Uncertainty in Mechanical Engineering}, booktitle = {Mastering Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78356-3}, pages = {429 -- 433}, year = {2021}, language = {en} } @incollection{LeiseAltherr2021, author = {Leise, Philipp and Altherr, Lena}, title = {Experimental evaluation of resilience metrics in a fluid system}, series = {Mastering Uncertainty in Mechanical Engineering}, booktitle = {Mastering Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78356-3}, pages = {442 -- 447}, year = {2021}, language = {en} } @inproceedings{NikolovskiRekeElsenetal.2021, author = {Nikolovski, Gjorgji and Reke, Michael and Elsen, Ingo and Schiffer, Stefan}, title = {Machine learning based 3D object detection for navigation in unstructured environments}, series = {2021 IEEE Intelligent Vehicles Symposium Workshops (IV Workshops)}, booktitle = {2021 IEEE Intelligent Vehicles Symposium Workshops (IV Workshops)}, publisher = {IEEE}, isbn = {978-1-6654-7921-9}, doi = {10.1109/IVWorkshops54471.2021.9669218}, pages = {236 -- 242}, year = {2021}, abstract = {In this paper we investigate the use of deep neural networks for 3D object detection in uncommon, unstructured environments such as in an open-pit mine. While neural nets are frequently used for object detection in regular autonomous driving applications, more unusual driving scenarios aside street traffic pose additional challenges. For one, the collection of appropriate data sets to train the networks is an issue. For another, testing the performance of trained networks often requires tailored integration with the particular domain as well. While there exist different solutions for these problems in regular autonomous driving, there are only very few approaches that work for special domains just as well. We address both the challenges above in this work. First, we discuss two possible ways of acquiring data for training and evaluation. That is, we evaluate a semi-automated annotation of recorded LIDAR data and we examine synthetic data generation. Using these datasets we train and test different deep neural network for the task of object detection. Second, we propose a possible integration of a ROS2 detector module for an autonomous driving platform. Finally, we present the performance of three state-of-the-art deep neural networks in the domain of 3D object detection on a synthetic dataset and a smaller one containing a characteristic object from an open-pit mine.}, language = {en} } @inproceedings{RitschelStenzelCzarneckietal.2021, author = {Ritschel, Konstantin and Stenzel, Adina and Czarnecki, Christian and Hong, Chin-Gi}, title = {Realizing robotic process automation potentials: an architectural perspective on a real-life implementation case}, series = {GI Edition Proceedings Band 314 "INFORMATIK 2021" Computer Science \& Sustainability}, booktitle = {GI Edition Proceedings Band 314 "INFORMATIK 2021" Computer Science \& Sustainability}, editor = {Gesellschaft f{\"u}r Informatik e.V. (GI),}, publisher = {K{\"o}llen}, address = {Bonn}, isbn = {9783885797081}, issn = {1617-5468}, doi = {10.18420/informatik2021-108}, pages = {1303 -- 1311}, year = {2021}, abstract = {The initial idea of Robotic Process Automation (RPA) is the automation of business processes through a simple emulation of user input and output by software robots. Hence, it can be assumed that no changes of the used software systems and existing Enterprise Architecture (EA) is required. In this short, practical paper we discuss this assumption based on a real-life implementation project. We show that a successful RPA implementation might require architectural work during analysis, implementation, and migration. As practical paper we focus on exemplary lessons-learned and new questions related to RPA and EA.}, language = {en} } @incollection{CzarneckiHongSchmitzetal.2021, author = {Czarnecki, Christian and Hong, Chin-Gi and Schmitz, Manfred and Dietze, Christian}, title = {Enabling digital transformation through cognitive robotic process automation at Deutsche Telekom Services Europe}, series = {Digitalization Cases Vol. 2 : Mastering digital transformation for global business}, booktitle = {Digitalization Cases Vol. 2 : Mastering digital transformation for global business}, editor = {Urbach, Nils and R{\"o}glinger, Maximilian and Kautz, Karlheinz and Alias, Rose Alinda and Saunders, Carol and Wiener, Martin}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-80002-4 (Print)}, doi = {10.1007/978-3-030-80003-1}, pages = {123 -- 138}, year = {2021}, abstract = {Subject of this case is Deutsche Telekom Services Europe (DTSE), a service center for administrative processes. Due to the high volume of repetitive tasks (e.g., 100k manual uploads of offer documents into SAP per year), automation was identified as an important strategic target with a high management attention and commitment. DTSE has to work with various backend application systems without any possibility to change those systems. Furthermore, the complexity of administrative processes differed. When it comes to the transfer of unstructured data (e.g., offer documents) to structured data (e.g., MS Excel files), further cognitive technologies were needed.}, language = {en} } @incollection{CzarneckiFettke2021, author = {Czarnecki, Christian and Fettke, Peter}, title = {Robotic process automation : Positioning, structuring, and framing the work}, series = {Robotic process automation : Management, technology, applications}, booktitle = {Robotic process automation : Management, technology, applications}, editor = {Czarnecki, Christian and Fettke, Peter}, publisher = {De Gruyter}, address = {Oldenbourg}, isbn = {978-3-11-067668-6 (Print)}, doi = {10.1515/9783110676693-202}, pages = {3 -- 24}, year = {2021}, abstract = {Robotic process automation (RPA) has attracted increasing attention in research and practice. This chapter positions, structures, and frames the topic as an introduction to this book. RPA is understood as a broad concept that comprises a variety of concrete solutions. From a management perspective RPA offers an innovative approach for realizing automation potentials, whereas from a technical perspective the implementation based on software products and the impact of artificial intelligence (AI) and machine learning (ML) are relevant. RPA is industry-independent and can be used, for example, in finance, telecommunications, and the public sector. With respect to RPA this chapter discusses definitions, related approaches, a structuring framework, a research framework, and an inside as well as outside architectural view. Furthermore, it provides an overview of the book combined with short summaries of each chapter.}, language = {en} } @incollection{BensbergAuthCzarnecki2021, author = {Bensberg, Frank and Auth, Gunnar and Czarnecki, Christian}, title = {Finding the perfect RPA match : a criteria-based selection method for RPA solutions}, series = {Robotic process automation : Management, technology, applications}, booktitle = {Robotic process automation : Management, technology, applications}, editor = {Czarnecki, Christian and Fettke, Peter}, publisher = {De Gruyter}, address = {Oldenbourg}, isbn = {978-3-11-067677-8}, doi = {10.1515/9783110676693-201}, pages = {47 -- 75}, year = {2021}, abstract = {The benefits of robotic process automation (RPA) are highly related to the usage of commercial off-the-shelf (COTS) software products that can be easily implemented and customized by business units. But, how to find the best fitting RPA product for a specific situation that creates the expected benefits? This question is related to the general area of software evaluation and selection. In the face of more than 75 RPA products currently on the market, guidance considering those specifics is required. Therefore, this chapter proposes a criteria-based selection method specifically for RPA. The method includes a quantitative evaluation of costs and benefits as well as a qualitative utility analysis based on functional criteria. By using the visualization of financial implications (VOFI) method, an application-oriented structure is provided that opposes the total cost of ownership to the time savings times salary (TSTS). For the utility analysis a detailed list of functional criteria for RPA is offered. The whole method is based on a multi-vocal review of scientific and non-scholarly literature including publications by business practitioners, consultants, and vendors. The application of the method is illustrated by a concrete RPA example. The illustrated structures, templates, and criteria can be directly utilized by practitioners in their real-life RPA implementations. In addition, a normative decision process for selecting RPA alternatives is proposed before the chapter closes with a discussion and outlook.}, language = {en} } @incollection{CroonCzarnecki2021, author = {Croon, Philipp and Czarnecki, Christian}, title = {Liability for loss or damages caused by RPA}, series = {Robotic process automation : Management, technology, applications}, booktitle = {Robotic process automation : Management, technology, applications}, editor = {Czarnecki, Christian and Fettke, Peter}, publisher = {De Gruyter}, address = {Oldenbourg}, isbn = {9783110676778}, doi = {10.1515/9783110676693-202}, pages = {135 -- 151}, year = {2021}, abstract = {Intelligent autonomous software robots replacing human activities and performing administrative processes are reality in today's corporate world. This includes, for example, decisions about invoice payments, identification of customers for a marketing campaign, and answering customer complaints. What happens if such a software robot causes a damage? Due to the complete absence of human activities, the question is not trivial. It could even happen that no one is liable for a damage towards a third party, which could create an uncalculatable legal risk for business partners. Furthermore, the implementation and operation of those software robots involves various stakeholders, which result in the unsolvable endeavor of identifying the originator of a damage. Overall it is advisable to all involved parties to carefully consider the legal situation. This chapter discusses the liability of software robots from an interdisciplinary perspective. Based on different technical scenarios the legal aspects of liability are discussed.}, language = {en} } @article{OliveiraMolinnusBegingetal.2021, author = {Oliveira, Danilo A. and Molinnus, Denise and Beging, Stefan and Siqueira Jr, Jos{\´e} R. and Sch{\"o}ning, Michael Josef}, title = {Biosensor Based on Self-Assembled Films of Graphene Oxide and Polyaniline Using a Field-Effect Device Platform}, series = {physica status solidi (a) applications and materials science}, volume = {218}, journal = {physica status solidi (a) applications and materials science}, number = {13}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.202000747}, pages = {1 -- 9}, year = {2021}, abstract = {A new functionalization method to modify capacitive electrolyte-insulator-semiconductor (EIS) structures with nanofilms is presented. Layers of polyallylamine hydrochloride (PAH) and graphene oxide (GO) with the compound polyaniline:poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PANI:PAAMPSA) are deposited onto a p-Si/SiO2 chip using the layer-by-layer technique (LbL). Two different enzymes (urease and penicillinase) are separately immobilized on top of a five-bilayer stack of the PAH:GO/PANI:PAAMPSA-modified EIS chip, forming a biosensor for detection of urea and penicillin, respectively. Electrochemical characterization is performed by constant capacitance (ConCap) measurements, and the film morphology is characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). An increase in the average sensitivity of the modified biosensors (EIS-nanofilm-enzyme) of around 15\% is found in relation to sensors, only carrying the enzyme but without the nanofilm (EIS-enzyme). In this sense, the nanofilm acts as a stable bioreceptor onto the EIS chip improving the output signal in terms of sensitivity and stability.}, language = {en} } @article{WeldenNagamineKomesuWagneretal.2021, author = {Welden, Rene and Nagamine Komesu, Cindy A. and Wagner, Patrick H. and Sch{\"o}ning, Michael Josef and Wagner, Torsten}, title = {Photoelectrochemical enzymatic penicillin biosensor: A proof-of-concept experiment}, series = {Electrochemical Science Advances}, volume = {2}, journal = {Electrochemical Science Advances}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2698-5977}, doi = {10.1002/elsa.202100131}, pages = {1 -- 5}, year = {2021}, abstract = {Photoelectrochemical (PEC) biosensors are a rather novel type of biosensors thatutilizelighttoprovideinformationaboutthecompositionofananalyte,enablinglight-controlled multi-analyte measurements. For enzymatic PEC biosensors,amperometric detection principles are already known in the literature. In con-trast, there is only a little information on H+-ion sensitive PEC biosensors. Inthis work, we demonstrate the detection of H+ions emerged by H+-generatingenzymes, exemplarily demonstrated with penicillinase as a model enzyme on atitanium dioxide photoanode. First, we describe the pH sensitivity of the sensorand study possible photoelectrocatalytic reactions with penicillin. Second, weshow the enzymatic PEC detection of penicillin.}, language = {en} } @article{RichterBraunsteinStaeudleetal.2021, author = {Richter, Charlotte and Braunstein, Bjoern and Staeudle, Benjamin and Attias, Julia and Suess, Alexander and Weber, Tobias and Mileva, Katya N. and Rittweger, Joern and Green, David A. and Albracht, Kirsten}, title = {Contractile behavior of the gastrocnemius medialis muscle during running in simulated hypogravity}, series = {npj Microgravity}, volume = {7}, journal = {npj Microgravity}, number = {Article number: 32}, publisher = {Springer Nature}, address = {New York}, issn = {2373-8065}, doi = {10.1038/s41526-021-00155-7}, pages = {7 Seiten}, year = {2021}, abstract = {Vigorous exercise countermeasures in microgravity can largely attenuate muscular degeneration, albeit the extent of applied loading is key for the extent of muscle wasting. Running on the International Space Station is usually performed with maximum loads of 70\% body weight (0.7 g). However, it has not been investigated how the reduced musculoskeletal loading affects muscle and series elastic element dynamics, and thereby force and power generation. Therefore, this study examined the effects of running on the vertical treadmill facility, a ground-based analog, at simulated 0.7 g on gastrocnemius medialis contractile behavior. The results reveal that fascicle-series elastic element behavior differs between simulated hypogravity and 1 g running. Whilst shorter peak series elastic element lengths at simulated 0.7 g appear to be the result of lower muscular and gravitational forces acting on it, increased fascicle lengths and decreased velocities could not be anticipated, but may inform the development of optimized running training in hypogravity. However, whether the alterations in contractile behavior precipitate musculoskeletal degeneration warrants further study.}, language = {en} } @inproceedings{KronigerHorikawaFunkeetal.2021, author = {Kroniger, Daniel and Horikawa, Atsushi and Funke, Harald and Pf{\"a}ffle, Franziska}, title = {Numerical investigation of micromix hydrogen flames at different combustor pressure levels}, series = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, booktitle = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, doi = {10.1299/jsmeicope.2021.15.2021-0237}, pages = {4 Seiten}, year = {2021}, abstract = {This study investigates the influence of pressure on the temperature distribution of the micromix (MMX) hydrogen flame and the NOx emissions. A steady computational fluid dynamic (CFD) analysis is performed by simulating a reactive flow with a detailed chemical reaction model. The numerical analysis is validated based on experimental investigations. A quantitative correlation is parametrized based on the numerical results. We find, that the flame initiation point shifts with increasing pressure from anchoring behind a downstream located bluff body towards anchoring upstream at the hydrogen jet. The numerical NOx emissions trend regarding to a variation of pressure is in good agreement with the experimental results. The pressure has an impact on both, the residence time within the maximum temperature region and on the peak temperature itself. In conclusion, the numerical model proved to be adequate for future prototype design exploration studies targeting on improving the operating range.}, language = {en} } @inproceedings{HorikawaOkadaYamaguchietal.2021, author = {Horikawa, Atsushi and Okada, Kunio and Yamaguchi, Masato and Aoki, Shigeki and Wirsum, Manfred and Funke, Harald and Kusterer, Karsten}, title = {Combustor development and engine demonstration of micro-mix hydrogen combustion applied to M1A-17 gas turbine}, series = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3B: Combustion, Fuels, and Emissions}, booktitle = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3B: Combustion, Fuels, and Emissions}, doi = {10.1115/GT2021-59666}, pages = {13 Seiten}, year = {2021}, abstract = {Kawasaki Heavy Industries, LTD. (KHI) has research and development projects for a future hydrogen society. These projects comprise the complete hydrogen cycle, including the production of hydrogen gas, the refinement and liquefaction for transportation and storage, and finally the utilization in a gas turbine for electricity and heat supply. Within the development of the hydrogen gas turbine, the key technology is stable and low NOx hydrogen combustion, namely the Dry Low NOx (DLN) hydrogen combustion. KHI, Aachen University of Applied Science, and B\&B-AGEMA have investigated the possibility of low NOx micro-mix hydrogen combustion and its application to an industrial gas turbine combustor. From 2014 to 2018, KHI developed a DLN hydrogen combustor for a 2MW class industrial gas turbine with the micro-mix technology. Thereby, the ignition performance, the flame stability for equivalent rotational speed, and higher load conditions were investigated. NOx emission values were kept about half of the Air Pollution Control Law in Japan: 84ppm (O2-15\%). Hereby, the elementary combustor development was completed. From May 2020, KHI started the engine demonstration operation by using an M1A-17 gas turbine with a co-generation system located in the hydrogen-fueled power generation plant in Kobe City, Japan. During the first engine demonstration tests, adjustments of engine starting and load control with fuel staging were investigated. On 21st May, the electrical power output reached 1,635 kW, which corresponds to 100\% load (ambient temperature 20 °C), and thereby NOx emissions of 65 ppm (O2-15, 60 RH\%) were verified. Here, for the first time, a DLN hydrogen-fueled gas turbine successfully generated power and heat.}, language = {en} } @inproceedings{KronigerHorikawaFunkeetal.2021, author = {Kroniger, Daniel and Horikawa, Atsushi and Funke, Harald and Pf{\"a}ffle, Franziska and Kishimoto, Tsuyoshi and Okada, Koichi}, title = {Experimental and numerical investigation on the effect of pressure on micromix hydrogen combustion}, series = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3A: Combustion, Fuels, and Emissions}, booktitle = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3A: Combustion, Fuels, and Emissions}, publisher = {ASME}, address = {New York, NY}, doi = {10.1115/GT2021-58926}, pages = {11 Seiten}, year = {2021}, abstract = {The micromix (MMX) combustion concept is a DLN gas turbine combustion technology designed for high hydrogen content fuels. Multiple non-premixed miniaturized flames based on jet in cross-flow (JICF) are inherently safe against flashback and ensure a stable operation in various operative conditions. The objective of this paper is to investigate the influence of pressure on the micromix flame with focus on the flame initiation point and the NOx emissions. A numerical model based on a steady RANS approach and the Complex Chemistry model with relevant reactions of the GRI 3.0 mechanism is used to predict the reactive flow and NOx emissions at various pressure conditions. Regarding the turbulence-chemical interaction, the Laminar Flame Concept (LFC) and the Eddy Dissipation Concept (EDC) are compared. The numerical results are validated against experimental results that have been acquired at a high pressure test facility for industrial can-type gas turbine combustors with regard to flame initiation and NOx emissions. The numerical approach is adequate to predict the flame initiation point and NOx emission trends. Interestingly, the flame shifts its initiation point during the pressure increase in upstream direction, whereby the flame attachment shifts from anchoring behind a downstream located bluff body towards anchoring directly at the hydrogen jet. The LFC predicts this change and the NOx emissions more accurately than the EDC. The resulting NOx correlation regarding the pressure is similar to a non-premixed type combustion configuration.}, language = {en} } @inproceedings{MuellerSchmittLeiseetal.2021, author = {M{\"u}ller, Tim M. and Schmitt, Andreas and Leise, Philipp and Meck, Tobias and Altherr, Lena and Pelz, Peter F. and Pfetsch, Marc E.}, title = {Validation of an optimized resilient water supply system}, series = {Uncertainty in Mechanical Engineering}, booktitle = {Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-77255-0}, doi = {10.1007/978-3-030-77256-7_7}, pages = {70 -- 80}, year = {2021}, abstract = {Component failures within water supply systems can lead to significant performance losses. One way to address these losses is the explicit anticipation of failures within the design process. We consider a water supply system for high-rise buildings, where pump failures are the most likely failure scenarios. We explicitly consider these failures within an early design stage which leads to a more resilient system, i.e., a system which is able to operate under a predefined number of arbitrary pump failures. We use a mathematical optimization approach to compute such a resilient design. This is based on a multi-stage model for topology optimization, which can be described by a system of nonlinear inequalities and integrality constraints. Such a model has to be both computationally tractable and to represent the real-world system accurately. We therefore validate the algorithmic solutions using experiments on a scaled test rig for high-rise buildings. The test rig allows for an arbitrary connection of pumps to reproduce scaled versions of booster station designs for high-rise buildings. We experimentally verify the applicability of the presented optimization model and that the proposed resilience properties are also fulfilled in real systems.}, language = {en} } @inproceedings{MandekarJentschLutzetal.2021, author = {Mandekar, Swati and Jentsch, Lina and Lutz, Kai and Behbahani, Mehdi and Melnykowycz, Mark}, title = {Earable design analysis for sleep EEG measurements}, series = {UbiComp '21}, booktitle = {UbiComp '21}, doi = {10.1145/3460418.3479328}, pages = {171 -- 175}, year = {2021}, abstract = {Conventional EEG devices cannot be used in everyday life and hence, past decade research has been focused on Ear-EEG for mobile, at-home monitoring for various applications ranging from emotion detection to sleep monitoring. As the area available for electrode contact in the ear is limited, the electrode size and location play a vital role for an Ear-EEG system. In this investigation, we present a quantitative study of ear-electrodes with two electrode sizes at different locations in a wet and dry configuration. Electrode impedance scales inversely with size and ranges from 450 kΩ to 1.29 MΩ for dry and from 22 kΩ to 42 kΩ for wet contact at 10 Hz. For any size, the location in the ear canal with the lowest impedance is ELE (Left Ear Superior), presumably due to increased contact pressure caused by the outer-ear anatomy. The results can be used to optimize signal pickup and SNR for specific applications. We demonstrate this by recording sleep spindles during sleep onset with high quality (5.27 μVrms).}, language = {en} } @article{HeinkeKnickerAlbracht2021, author = {Heinke, Lars N. and Knicker, Axel J. and Albracht, Kirsten}, title = {Test-retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men}, series = {Journal of Electromyography and Kinesiology}, volume = {62}, journal = {Journal of Electromyography and Kinesiology}, number = {Article 102611}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1050-6411}, doi = {10.1016/j.jelekin.2021.102611}, year = {2021}, abstract = {Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall "good" relative reliability. SRD 95\% lay between ±7,0 to ±12,3 ms.. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.}, language = {en} } @book{DiktaScheer2021, author = {Dikta, Gerhard and Scheer, Marsel}, title = {Bootstrap Methods: With Applications in R}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-73480-0}, doi = {10.1007/978-3-030-73480-0}, pages = {XVI, 256 Seiten}, year = {2021}, abstract = {This book provides a compact introduction to the bootstrap method. In addition to classical results on point estimation and test theory, multivariate linear regression models and generalized linear models are covered in detail. Special attention is given to the use of bootstrap procedures to perform goodness-of-fit tests to validate model or distributional assumptions. In some cases, new methods are presented here for the first time. The text is motivated by practical examples and the implementations of the corresponding algorithms are always given directly in R in a comprehensible form. Overall, R is given great importance throughout. Each chapter includes a section of exercises and, for the more mathematically inclined readers, concludes with rigorous proofs. The intended audience is graduate students who already have a prior knowledge of probability theory and mathematical statistics.}, language = {en} } @article{HeelDiktaBraekers2021, author = {Heel, Mareike van and Dikta, Gerhard and Braekers, Roel}, title = {Bootstrap based goodness‑of‑fit tests for binary multivariate regression models}, series = {Journal of the Korean Statistical Society}, volume = {51}, journal = {Journal of the Korean Statistical Society}, publisher = {Springer Nature}, address = {Singapur}, issn = {2005-2863 (Online)}, doi = {10.1007/s42952-021-00142-4}, pages = {28 Seiten}, year = {2021}, abstract = {We consider a binary multivariate regression model where the conditional expectation of a binary variable given a higher-dimensional input variable belongs to a parametric family. Based on this, we introduce a model-based bootstrap (MBB) for higher-dimensional input variables. This test can be used to check whether a sequence of independent and identically distributed observations belongs to such a parametric family. The approach is based on the empirical residual process introduced by Stute (Ann Statist 25:613-641, 1997). In contrast to Stute and Zhu's approach (2002) Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), a transformation is not required. Thus, any problems associated with non-parametric regression estimation are avoided. As a result, the MBB method is much easier for users to implement. To illustrate the power of the MBB based tests, a small simulation study is performed. Compared to the approach of Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), the simulations indicate a slightly improved power of the MBB based method. Finally, both methods are applied to a real data set.}, language = {en} } @inproceedings{HueningWacheMagiera2021, author = {H{\"u}ning, Felix and Wache, Franz-Josef and Magiera, David}, title = {Redundant bus systems using dual-mode radio}, series = {Proceedings of Sixth International Congress on Information and Communication Technology}, booktitle = {Proceedings of Sixth International Congress on Information and Communication Technology}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-16-2379-0}, doi = {10.1007/978-981-16-2380-6_73}, pages = {835 -- 842}, year = {2021}, abstract = {Communication via serial bus systems, like CAN, plays an important role for all kinds of embedded electronic and mechatronic systems. To cope up with the requirements for functional safety of safety-critical applications, there is a need to enhance the safety features of the communication systems. One measure to achieve a more robust communication is to add redundant data transmission path to the applications. In general, the communication of real-time embedded systems like automotive applications is tethered, and the redundant data transmission lines are also tethered, increasing the size of the wiring harness and the weight of the system. A radio link is preferred as a redundant transmission line as it uses a complementary transmission medium compared to the wired solution and in addition reduces wiring harness size and weight. Standard wireless links like Wi-Fi or Bluetooth cannot meet the requirements for real-time capability with regard to bus communication. Using the new dual-mode radio enables a redundant transmission line meeting all requirements with regard to real-time capability, robustness and transparency for the data bus. In addition, it provides a complementary transmission medium with regard to commonly used tethered links. A CAN bus system is used to demonstrate the redundant data transfer via tethered and wireless CAN.}, language = {en} } @inproceedings{KloeserKohlKraftetal.2021, author = {Kl{\"o}ser, Lars and Kohl, Philipp and Kraft, Bodo and Z{\"u}ndorf, Albert}, title = {Multi-attribute relation extraction (MARE): simplifying the application of relation extraction}, series = {Proceedings of the 2nd International Conference on Deep Learning Theory and Applications DeLTA - Volume 1}, booktitle = {Proceedings of the 2nd International Conference on Deep Learning Theory and Applications DeLTA - Volume 1}, publisher = {SciTePress}, address = {Set{\´u}bal}, isbn = {978-989-758-526-5}, doi = {10.5220/0010559201480156}, pages = {148 -- 156}, year = {2021}, abstract = {Natural language understanding's relation extraction makes innovative and encouraging novel business concepts possible and facilitates new digitilized decision-making processes. Current approaches allow the extraction of relations with a fixed number of entities as attributes. Extracting relations with an arbitrary amount of attributes requires complex systems and costly relation-trigger annotations to assist these systems. We introduce multi-attribute relation extraction (MARE) as an assumption-less problem formulation with two approaches, facilitating an explicit mapping from business use cases to the data annotations. Avoiding elaborated annotation constraints simplifies the application of relation extraction approaches. The evaluation compares our models to current state-of-the-art event extraction and binary relation extraction methods. Our approaches show improvement compared to these on the extraction of general multi-attribute relations.}, language = {en} } @inproceedings{KohlSchmidtsKloeseretal.2021, author = {Kohl, Philipp and Schmidts, Oliver and Kl{\"o}ser, Lars and Werth, Henri and Kraft, Bodo and Z{\"u}ndorf, Albert}, title = {STAMP 4 NLP - an agile framework for rapid quality-driven NLP applications development}, series = {Quality of Information and Communications Technology. QUATIC 2021}, booktitle = {Quality of Information and Communications Technology. QUATIC 2021}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-85346-4}, doi = {10.1007/978-3-030-85347-1_12}, pages = {156 -- 166}, year = {2021}, abstract = {The progress in natural language processing (NLP) research over the last years, offers novel business opportunities for companies, as automated user interaction or improved data analysis. Building sophisticated NLP applications requires dealing with modern machine learning (ML) technologies, which impedes enterprises from establishing successful NLP projects. Our experience in applied NLP research projects shows that the continuous integration of research prototypes in production-like environments with quality assurance builds trust in the software and shows convenience and usefulness regarding the business goal. We introduce STAMP 4 NLP as an iterative and incremental process model for developing NLP applications. With STAMP 4 NLP, we merge software engineering principles with best practices from data science. Instantiating our process model allows efficiently creating prototypes by utilizing templates, conventions, and implementations, enabling developers and data scientists to focus on the business goals. Due to our iterative-incremental approach, businesses can deploy an enhanced version of the prototype to their software environment after every iteration, maximizing potential business value and trust early and avoiding the cost of successful yet never deployed experiments.}, language = {en} } @inproceedings{SchmidtsKraftWinkensetal.2021, author = {Schmidts, Oliver and Kraft, Bodo and Winkens, Marvin and Z{\"u}ndorf, Albert}, title = {Catalog integration of heterogeneous and volatile product data}, series = {DATA 2020: Data Management Technologies and Applications}, booktitle = {DATA 2020: Data Management Technologies and Applications}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-83013-7}, doi = {10.1007/978-3-030-83014-4_7}, pages = {134 -- 153}, year = {2021}, abstract = {The integration of frequently changing, volatile product data from different manufacturers into a single catalog is a significant challenge for small and medium-sized e-commerce companies. They rely on timely integrating product data to present them aggregated in an online shop without knowing format specifications, concept understanding of manufacturers, and data quality. Furthermore, format, concepts, and data quality may change at any time. Consequently, integrating product catalogs into a single standardized catalog is often a laborious manual task. Current strategies to streamline or automate catalog integration use techniques based on machine learning, word vectorization, or semantic similarity. However, most approaches struggle with low-quality or real-world data. We propose Attribute Label Ranking (ALR) as a recommendation engine to simplify the integration process of previously unknown, proprietary tabular format into a standardized catalog for practitioners. We evaluate ALR by focusing on the impact of different neural network architectures, language features, and semantic similarity. Additionally, we consider metrics for industrial application and present the impact of ALR in production and its limitations.}, language = {en} } @incollection{PfetschAbeleAltherretal.2021, author = {Pfetsch, Marc E. and Abele, Eberhard and Altherr, Lena and B{\"o}lling, Christian and Br{\"o}tz, Nicolas and Dietrich, Ingo and Gally, Tristan and Geßner, Felix and Groche, Peter and Hoppe, Florian and Kirchner, Eckhard and Kloberdanz, Hermann and Knoll, Maximilian and Kolvenbach, Philip and Kuttich-Meinlschmidt, Anja and Leise, Philipp and Lorenz, Ulf and Matei, Alexander and Molitor, Dirk A. and Niessen, Pia and Pelz, Peter F. and Rexer, Manuel and Schmitt, Andreas and Schmitt, Johann M. and Schulte, Fiona and Ulbrich, Stefan and Weigold, Matthias}, title = {Strategies for mastering uncertainty}, series = {Mastering uncertainty in mechanical engineering}, booktitle = {Mastering uncertainty in mechanical engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78353-2}, doi = {10.1007/978-3-030-78354-9_6}, pages = {365 -- 456}, year = {2021}, abstract = {This chapter describes three general strategies to master uncertainty in technical systems: robustness, flexibility and resilience. It builds on the previous chapters about methods to analyse and identify uncertainty and may rely on the availability of technologies for particular systems, such as active components. Robustness aims for the design of technical systems that are insensitive to anticipated uncertainties. Flexibility increases the ability of a system to work under different situations. Resilience extends this characteristic by requiring a given minimal functional performance, even after disturbances or failure of system components, and it may incorporate recovery. The three strategies are described and discussed in turn. Moreover, they are demonstrated on specific technical systems.}, language = {en} } @article{BraunChengDoweyetal.2021, author = {Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Performance evaluation of skill-based order-assignment in production environments with multi-agent systems}, series = {IEEE Journal of Emerging and Selected Topics in Industrial Electronics}, journal = {IEEE Journal of Emerging and Selected Topics in Industrial Electronics}, number = {Early Access}, publisher = {IEEE}, address = {New York}, issn = {2687-9735}, doi = {10.1109/JESTIE.2021.3108524}, year = {2021}, abstract = {The fourth industrial revolution introduces disruptive technologies to production environments. One of these technologies are multi-agent systems (MASs), where agents virtualize machines. However, the agent's actual performances in production environments can hardly be estimated as most research has been focusing on isolated projects and specific scenarios. We address this gap by implementing a highly connected and configurable reference model with quantifiable key performance indicators (KPIs) for production scheduling and routing in single-piece workflows. Furthermore, we propose an algorithm to optimize the search of extrema in highly connected distributed systems. The benefits, limits, and drawbacks of MASs and their performances are evaluated extensively by event-based simulations against the introduced model, which acts as a benchmark. Even though the performance of the proposed MAS is, on average, slightly lower than the reference system, the increased flexibility allows it to find new solutions and deliver improved factory-planning outcomes. Our MAS shows an emerging behavior by using flexible production techniques to correct errors and compensate for bottlenecks. This increased flexibility offers substantial improvement potential. The general model in this paper allows the transfer of the results to estimate real systems or other models.}, language = {en} } @article{JildehWagnerSchoening2021, author = {Jildeh, Zaid B. and Wagner, Patrick H. and Sch{\"o}ning, Michael Josef}, title = {Sterilization of Objects, Products, and Packaging Surfaces and Their Characterization in Different Fields of Industry: The Status in 2020}, series = {physica status solidi (a) applications and materials science}, volume = {218}, journal = {physica status solidi (a) applications and materials science}, number = {13}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.202000732}, pages = {27 Seiten}, year = {2021}, abstract = {The treatment method to deactivate viable microorganisms from objects or products is termed sterilization. There are multiple forms of sterilization, each intended to be applied for a specific target, which depends on—but not limited to—the thermal, physical, and chemical stability of that target. Herein, an overview on the currently used sterilization processes in the global market is provided. Different sterilization techniques are grouped under a category that describes the method of treatment: radiation (gamma, electron beam, X-ray, and ultraviolet), thermal (dry and moist heat), and chemical (ethylene oxide, ozone, chlorine dioxide, and hydrogen peroxide). For each sterilization process, the typical process parameters as defined by regulations and the mode of antimicrobial activity are summarized. Finally, the recommended microorganisms that are used as biological indicators to validate sterilization processes in accordance with the rules that are established by various regulatory agencies are summarized.}, language = {en} } @phdthesis{Bayer2021, author = {Bayer, Robin}, title = {Development of a novel in-vitro vascular model for determination of physiological and pathophysiological mechanobiology}, publisher = {Universit{\"a}t zu K{\"o}ln}, address = {K{\"o}ln}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:38-362212}, pages = {IV, 115 Seiten}, year = {2021}, language = {en} } @article{MolinnusDrinicIkenetal.2021, author = {Molinnus, Denise and Drinic, Aleksander and Iken, Heiko and Kr{\"o}ger, Nadja and Zinser, Max and Smeets, Ralf and K{\"o}pf, Marius and Kopp, Alexander and Sch{\"o}ning, Michael Josef}, title = {Towards a flexible electrochemical biosensor fabricated from biocompatible Bombyx mori silk}, series = {Biosensors and Bioelectronics}, volume = {183}, journal = {Biosensors and Bioelectronics}, number = {Art. 113204}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2021.113204}, year = {2021}, language = {en} } @article{YoshinobuSchoening2021, author = {Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {Light-addressable potentiometric sensors (LAPS) for cell monitoring and biosensing}, series = {Current Opinion in Electrochemistry}, journal = {Current Opinion in Electrochemistry}, number = {In Press, Journal Pre-proof}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2451-9103}, doi = {10.1016/j.coelec.2021.100727}, year = {2021}, language = {en} } @article{Maurischat2021, author = {Maurischat, Andreas}, title = {Algebraic independence of the Carlitz period and its hyperderivatives}, pages = {1 -- 12}, year = {2021}, language = {en} } @article{WertIkenSchoeningetal.2021, author = {Wert, Stefan and Iken, Heiko and Sch{\"o}ning, Michael Josef and Matysik, Frank-Michael}, title = {Development of a temperature-pulse enhanced electrochemical glucose biosensor and characterization of its stability via scanning electrochemical microscopy}, series = {Electroanalysis}, journal = {Electroanalysis}, number = {Early View}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-4109}, doi = {10.1002/elan.202100089}, year = {2021}, abstract = {Glucose oxidase (GOx) is an enzyme frequently used in glucose biosensors. As increased temperatures can enhance the performance of electrochemical sensors, we investigated the impact of temperature pulses on GOx that was drop-coated on flattened Pt microwires. The wires were heated by an alternating current. The sensitivity towards glucose and the temperature stability of GOx was investigated by amperometry. An up to 22-fold increase of sensitivity was observed. Spatially resolved enzyme activity changes were investigated via scanning electrochemical microscopy. The application of short (<100 ms) heat pulses was associated with less thermal inactivation of the immobilized GOx than long-term heating.}, language = {en} } @article{LowisFergusonPaulssenetal.2021, author = {Lowis, Carsten and Ferguson, Simon and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Improved Sc-44 production in a siphon-style liquid target on a medical cyclotron}, series = {Applied Radiation and Isotopes}, volume = {172}, journal = {Applied Radiation and Isotopes}, number = {Art. 109675}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0969-8043}, doi = {10.1016/j.apradiso.2021.109675}, year = {2021}, language = {en} } @article{WaldvogelRitzmannFreyleretal.2021, author = {Waldvogel, Janice and Ritzmann, Ramona and Freyler, Kathrin and Helm, Michael and Monti, Elena and Albracht, Kirsten and St{\"a}udle, Benjamin and Gollhofer, Albert and Narici, Marco}, title = {The Anticipation of Gravity in Human Ballistic Movement}, series = {Frontiers in Physiology}, journal = {Frontiers in Physiology}, publisher = {Frontiers}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2021.614060}, year = {2021}, abstract = {Stretch-shortening type actions are characterized by lengthening of the pre-activated muscle-tendon unit (MTU) in the eccentric phase immediately followed by muscle shortening. Under 1 g, pre-activity before and muscle activity after ground contact, scale muscle stiffness, which is crucial for the recoil properties of the MTU in the subsequent push-off. This study aimed to examine the neuro-mechanical coupling of the stretch-shortening cycle in response to gravity levels ranging from 0.1 to 2 g. During parabolic flights, 17 subjects performed drop jumps while electromyography (EMG) of the lower limb muscles was combined with ultrasound images of the gastrocnemius medialis, 2D kinematics and kinetics to depict changes in energy management and performance. Neuro-mechanical coupling in 1 g was characterized by high magnitudes of pre-activity and eccentric muscle activity allowing an isometric muscle behavior during ground contact. EMG during pre-activity and the concentric phase systematically increased from 0.1 to 1 g. Below 1 g the EMG in the eccentric phase was diminished, leading to muscle lengthening and reduced MTU stretches. Kinetic energy at take-off and performance were decreased compared to 1 g. Above 1 g, reduced EMG in the eccentric phase was accompanied by large MTU and muscle stretch, increased joint flexion amplitudes, energy loss and reduced performance. The energy outcome function established by linear mixed model reveals that the central nervous system regulates the extensor muscles phase- and load-specifically. In conclusion, neuro-mechanical coupling appears to be optimized in 1 g. Below 1 g, the energy outcome is compromised by reduced muscle stiffness. Above 1 g, loading progressively induces muscle lengthening, thus facilitating energy dissipation.}, language = {en} } @article{BohndickBosseJaenschetal.2021, author = {Bohndick, Carla and Bosse, Elke and J{\"a}nsch, Vanessa K. and Barnat, Miriam}, title = {How different diversity factors affect the perception of first-year requirements in higher education}, series = {Frontline Learning Research}, volume = {9}, journal = {Frontline Learning Research}, number = {2}, publisher = {EARLI}, issn = {2295-3159}, doi = {10.14786/flr.v9i2.667}, pages = {78 -- 95}, year = {2021}, abstract = {In the light of growing university entry rates, higher education institutions not only serve larger numbers of students, but also seek to meet first-year students' ever more diverse needs. Yet to inform universities how to support the transition to higher education, research only offers limited insights. Current studies tend to either focus on the individual factors that affect student success or they highlight students' social background and their educational biography in order to examine the achievement of selected, non-traditional groups of students. Both lines of research appear to lack integration and often fail to take organisational diversity into account, such as different types of higher education institutions or degree programmes. For a more comprehensive understanding of student diversity, the present study includes individual, social and organisational factors. To gain insights into their role for the transition to higher education, we examine how the different factors affect the students' perception of the formal and informal requirements of the first year as more or less difficult to cope with. As the perceived requirements result from both the characteristics of the students and the institutional context, they allow to investigate transition at the interface of the micro and the meso level of higher education. Latent profile analyses revealed that there are no profiles with complex patterns of perception of the first-year requirements, but the identified groups rather differ in the overall level of perceived challenges. Moreover, SEM indicates that the differences in the perception largely depend on the individual factors self-efficacy and volition.}, language = {en} } @article{HugenrothNeidlinEngelmannetal.2021, author = {Hugenroth, Kristin and Neidlin, Michael and Engelmann, Ulrich M. and Kaufmann, Tim A. S. and Steinseifer, Ulrich and Heilmann, Torsten}, title = {Tipless Transseptal Cannula Concept Combines Improved Hemodynamic Properties and Risk-Reduced Placement: an In Silico Proof-of-Concept}, series = {Artificial Organs}, journal = {Artificial Organs}, number = {Accepted Article}, publisher = {Wiley}, address = {Weinheim}, issn = {1525-1594}, doi = {10.1111/aor.13964}, year = {2021}, language = {en} } @article{GivanoudiCornelisRasschaertetal.2021, author = {Givanoudi, Stella and Cornelis, Peter and Rasschaert, Geertrui and Wackers, Gideon and Iken, Heiko and Rolka, David and Yongabi, Derick and Robbens, Johan and Sch{\"o}ning, Michael Josef and Heyndrickx, Marc and Wagner, Patrick}, title = {Selective Campylobacter detection and quantification in poultry: A sensor tool for detecting the cause of a common zoonosis at its source}, series = {Sensors and Actuators B: Chemical}, journal = {Sensors and Actuators B: Chemical}, number = {In Press, Journal Pre-proof}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2021.129484}, pages = {Article 129484}, year = {2021}, language = {en} } @article{RichterBraunsteinStaeudleetal.2021, author = {Richter, Charlotte and Braunstein, Bjoern and St{\"a}udle, Benjamin and Attias, Julia and Suess, Alexander and Weber, Tobias and Mileva, Katja N. and Rittweger, Joern and Green, David A. and Albracht, Kirsten}, title = {Gastrocnemius medialis contractile behavior is preserved during 30\% body weight supported gait training}, series = {Frontiers in Sports and Active Living}, volume = {2021}, journal = {Frontiers in Sports and Active Living}, number = {2}, publisher = {Frontiers}, address = {Lausanne}, issn = {2624-9367}, doi = {10.3389/fspor.2020.614559}, pages = {Artikel 614559}, year = {2021}, abstract = {Rehabilitative body weight supported gait training aims at restoring walking function as a key element in activities of daily living. Studies demonstrated reductions in muscle and joint forces, while kinematic gait patterns appear to be preserved with up to 30\% weight support. However, the influence of body weight support on muscle architecture, with respect to fascicle and series elastic element behavior is unknown, despite this having potential clinical implications for gait retraining. Eight males (31.9 ± 4.7 years) walked at 75\% of the speed at which they typically transition to running, with 0\% and 30\% body weight support on a lower-body positive pressure treadmill. Gastrocnemius medialis fascicle lengths and pennation angles were measured via ultrasonography. Additionally, joint kinematics were analyzed to determine gastrocnemius medialis muscle-tendon unit lengths, consisting of the muscle's contractile and series elastic elements. Series elastic element length was assessed using a muscle-tendon unit model. Depending on whether data were normally distributed, a paired t-test or Wilcoxon signed rank test was performed to determine if body weight supported walking had any effects on joint kinematics and fascicle-series elastic element behavior. Walking with 30\% body weight support had no statistically significant effect on joint kinematics and peak series elastic element length. Furthermore, at the time when peak series elastic element length was achieved, and on average across the entire stance phase, muscle-tendon unit length, fascicle length, pennation angle, and fascicle velocity were unchanged with respect to body weight support. In accordance with unchanged gait kinematics, preservation of fascicle-series elastic element behavior was observed during walking with 30\% body weight support, which suggests transferability of gait patterns to subsequent unsupported walking.}, language = {en} } @article{RichterBraunsteinStaeudleetal.2021, author = {Richter, Charlotte and Braunstein, Bj{\"o}rn and St{\"a}udle, Benjamin and Attias, Julia and S{\"u}ss, Alexander and Weber, Tobias and Mileva, Katya N. and Rittweger, J{\"o}rn and Green, David A. and Albracht, Kirsten}, title = {Gastrocnemius medialis contractile behavior during running differs between simulated Lunar and Martian gravities}, series = {Scientific reports}, volume = {11}, journal = {Scientific reports}, number = {Article number: 22555}, publisher = {Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-021-00527-9}, pages = {13 Seiten}, year = {2021}, abstract = {The international partnership of space agencies has agreed to proceed forward to the Moon sustainably. Activities on the Lunar surface (0.16 g) will allow crewmembers to advance the exploration skills needed when expanding human presence to Mars (0.38 g). Whilst data from actual hypogravity activities are limited to the Apollo missions, simulation studies have indicated that ground reaction forces, mechanical work, muscle activation, and joint angles decrease with declining gravity level. However, these alterations in locomotion biomechanics do not necessarily scale to the gravity level, the reduction in gastrocnemius medialis activation even appears to level off around 0.2 g, while muscle activation pattern remains similar. Thus, it is difficult to predict whether gastrocnemius medialis contractile behavior during running on Moon will basically be the same as on Mars. Therefore, this study investigated lower limb joint kinematics and gastrocnemius medialis behavior during running at 1 g, simulated Martian gravity, and simulated Lunar gravity on the vertical treadmill facility. The results indicate that hypogravity-induced alterations in joint kinematics and contractile behavior still persist between simulated running on the Moon and Mars. This contrasts with the concept of a ceiling effect and should be carefully considered when evaluating exercise prescriptions and the transferability of locomotion practiced in Lunar gravity to Martian gravity.}, language = {en} }