@article{KobFrauenrath2009,
  author    = {Kob, Malte and Frauenrath, Tobias},
  title     = {A system for parallel measurement of glottis opening and larynx position},
  series = {Biomedical Signal Processing and Control},
  volume    = {4},
  journal   = {Biomedical Signal Processing and Control},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1746-8108},
  doi       = {10.1016/j.bspc.2009.03.004},
  pages     = {221 -- 228},
  year      = {2009},
  abstract  = {The simultaneous assessment of glottal dynamics and larynx position can be beneficial for the diagnosis of disordered voice or speech production and swallowing. Up to now, methods either concentrate on assessment of the glottis opening using optical, acoustical or electrical (electroglottography, EGG) methods, or on visualisation of the larynx position using ultrasound, computer tomography or magnetic resonance imaging techniques. The method presented here makes use of a time-multiplex measurement approach of space-resolved transfer impedances through the larynx. The fast sequence of measurements allows a quasi simultaneous assessment of both larynx position and EGG signal using up to 32 transmit-receive signal paths. The system assesses the dynamic opening status of the glottis as well as the vertical and back/forward motion of the larynx. Two electrode-arrays are used for the measurement of the electrical transfer impedance through the neck in different directions. From the acquired data the global and individual conductivity is calculated as well as a 2D point spatial representation of the minimum impedance. The position information is shown together with classical EGG signals allowing a synchronous visual assessment of glottal area and larynx position. A first application to singing voice analysis is presented that indicate a high potential of the method for use as a non-invasive tool in the diagnosis of voice, speech, and swallowing disorders.},
  language  = {en}
}
@article{HeinrichsUttingFrauenrathetal.2009,
  author    = {Heinrichs, Uwe and Utting, Jane F. and Frauenrath, Tobias and Hezel, Fabian and Krombach, Gabriele A. and Hodenius, Michael A. J. and Kozerke, Sebastian and Niendorf, Thoralf},
  title     = {Myocardial T2 mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T},
  series = {Magnetic Resonance in Medicine},
  volume    = {62},
  journal   = {Magnetic Resonance in Medicine},
  number    = {3},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1522-2594},
  doi       = {10.1002/mrm.22054},
  pages     = {822 -- 828},
  year      = {2009},
  abstract  = {This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T₂ mapping of the heart. First, T₂ maps are presented for oil phantoms without and with respiratory motion emulation (T₂ = (22.1 ± 1.7) ms at 1.5 T and T₂ = (22.65 ± 0.89) ms at 3.0 T). T₂ relaxometry of a ferrofluid revealed relaxivities of R2 = (477.9 ± 17) mM⁻¹s⁻¹ and R2 = (449.6 ± 13) mM⁻¹s⁻¹ for UFLARE and multiecho gradient-echo imaging at 1.5 T. For inferoseptal myocardial regions mean T₂ values of 29.9 ± 6.6 ms (1.5 T) and 22.3 ± 4.8 ms (3.0 T) were estimated. For posterior myocardial areas close to the vena cava T₂-values of 24.0 ± 6.4 ms (1.5 T) and 15.4 ± 1.8 ms (3.0 T) were observed. The merits and limitations of the proposed approach are discussed and its implications for cardiac and vascular T₂-mapping are considered.},
  language  = {en}
}
@article{FrauenrathNiendorfKob2008,
  author    = {Frauenrath, Tobias and Niendorf, Thoralf and Kob, Malte},
  title     = {Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)},
  series = {Acta Acustica},
  volume    = {94},
  journal   = {Acta Acustica},
  number    = {1},
  publisher = {Hirzel},
  address   = {Stuttgart},
  issn      = {1861-9959},
  doi       = {10.3813/AAA.918017},
  pages     = {148 -- 155},
  year      = {2008},
  abstract  = {Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds.},
  language  = {en}
}
@article{OehlenschlaegerVolkmarStiefelmaieretal.2024,
  author    = {Oehlenschl{\"a}ger, Katharina and Volkmar, Marianne and Stiefelmaier, Judith and Langsdorf, Alexander and Holtmann, Dirk and Tippk{\"o}tter, Nils and Ulber, Roland},
  title     = {New insights into the influence of pre-culture on robust solvent production of C. acetobutylicum},
  series = {Applied Microbiology and Biotechnology},
  volume    = {108},
  journal   = {Applied Microbiology and Biotechnology},
  publisher = {Springer},
  address   = {Berlin, Heidelberg},
  issn      = {1432-0614},
  doi       = {10.1007/s00253-023-12981-8},
  pages     = {10 Seiten},
  year      = {2024},
  abstract  = {Clostridia are known for their solvent production, especially the production of butanol. Concerning the projected depletion of fossil fuels, this is of great interest. The cultivation of clostridia is known to be challenging, and it is difficult to achieve reproducible results and robust processes. However, existing publications usually concentrate on the cultivation conditions of the main culture. In this paper, the influence of cryo-conservation and pre-culture on growth and solvent production in the resulting main cultivation are examined. A protocol was developed that leads to reproducible cultivations of Clostridium acetobutylicum. Detailed investigation of the cell conservation in cryo-cultures ensured reliable cell growth in the pre-culture. Moreover, a reason for the acid crash in the main culture was found, based on the cultivation conditions of the pre-culture. The critical parameter to avoid the acid crash and accomplish the shift to the solventogenesis of clostridia is the metabolic phase in which the cells of the pre-culture were at the time of inoculation of the main culture; this depends on the cultivation time of the pre-culture. Using cells from the exponential growth phase to inoculate the main culture leads to an acid crash. To achieve the solventogenic phase with butanol production, the inoculum should consist of older cells which are in the stationary growth phase. Considering these parameters, which affect the entire cultivation process, reproducible results and reliable solvent production are ensured.},
  language  = {en}
}
@article{HengsbachEngelCwienczeketal.2023,
  author    = {Hengsbach, Jan-Niklas and Engel, Mareike and Cwienczek, Marcel and Stiefelmaier, Judith and Tippk{\"o}tter, Nils and Ulber, Roland},
  title     = {Scalable unseparated bioelectrochemical reactors by using a carbon fiber brush as stirrer and working electrode},
  series = {ChemElectroChem},
  volume    = {10},
  journal   = {ChemElectroChem},
  number    = {21},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {2196-0216},
  doi       = {10.1002/celc.202300440},
  pages     = {9 Seiten},
  year      = {2023},
  abstract  = {The concept of energy conversion into platform chemicals using bioelectrochemical systems (BES) has gained increasing attention in recent years, as the technology simultaneously provides an opportunity for sustainable chemical production and tackles the challenge of Power-to-X technologies. There are many approaches to realize the industrial scale of BES. One concept is to equip standard bioreactors with static electrodes. However, large installations resulted in a negative influence on various reactor parameters. In this study, we present a new single-chamber BES based on a stirred tank reactor in which the stirrer was replaced by a carbon fiber brush, performing the functions of the working electrode and the stirrer. The reactor is characterized in abiotic studies and electro-fermentations with Clostridium acetobutylicum. Compared to standard reactors an increase in butanol production of 20.14±3.66 \% shows that the new BES can be efficiently used for bioelectrochemical processes.},
  language  = {en}
}
@article{vonKnobelsdorfBrenkenhoffFrauenrathProthmannetal.2010,
  author    = {von Knobelsdorf-Brenkenhoff, Florian and Frauenrath, Tobias and Prothmann, Marcel and Dieringer, Matthias A. and Hezel, Fabian and Renz, Wolfgang and Kretschel, Kerstin and Niendorf, Thoralf and Schulz-Menger, Jeanette},
  title     = {Cardiac chamber quantification using magnetic resonance imaging at 7 Tesla—a pilot study},
  volume    = {20},
  publisher = {Springer},
  address   = {Berlin, Heidelberg},
  issn      = {0938-7994},
  doi       = {10.1007/s00330-010-1888-2},
  pages     = {2844 -- 2852},
  year      = {2010},
  abstract  = {Objectives Interest in cardiovascular magnetic resonance (CMR) at 7 T is motivated by the expected increase in spatial and temporal resolution, but the method is technically challenging. We examined the feasibility of cardiac chamber quantification at 7 T. Methods A stack of short axes covering the left ventricle was obtained in nine healthy male volunteers. At 1.5 T, steady-state free precession (SSFP) and fast gradient echo (FGRE) cine imaging with 7 mm slice thickness (STH) were used. At 7 T, FGRE with 7 mm and 4 mm STH were applied. End-diastolic volume, end-systolic volume, ejection fraction and mass were calculated. Results All 7 T examinations provided excellent blood/myocardium contrast for all slice directions. No significant difference was found regarding ejection fraction and cardiac volumes between SSFP at 1.5 T and FGRE at 7 T, while volumes obtained from FGRE at 1.5 T were underestimated. Cardiac mass derived from FGRE at 1.5 and 7 T was larger than obtained from SSFP at 1.5 T. Agreement of volumes and mass between SSFP at 1.5 T and FGRE improved for FGRE at 7 T when combined with an STH reduction to 4 mm. Conclusions This pilot study demonstrates that cardiac chamber quantification at 7 T using FGRE is feasible and agrees closely with SSFP at 1.5 T.},
  language  = {en}
}
@inproceedings{LangohrBungCrookston2022,
  author    = {Langohr, Philipp and Bung, Daniel Bernhard and Crookston, Brian M.},
  title     = {Hybrid investigation of labyrinth weirs: Discharge capacity and energy dissipation},
  series = {Proceedings of the 39th IAHR World Congress},
  booktitle = {Proceedings of the 39th IAHR World Congress},
  editor    = {Ortega-S{\´a}nchez, Miguel},
  publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)},
  address   = {Madrid},
  isbn      = {978-90-832612-1-8},
  issn      = {2521-7119 (print)},
  doi       = {10.3850/IAHR-39WC252171192022738},
  pages     = {2313 -- 2318},
  year      = {2022},
  abstract  = {The replacement of existing spillway crests or gates with labyrinth weirs is a proven techno-economical means to increase the discharge capacity when rehabilitating existing structures. However, additional information is needed regarding energy dissipation of such weirs, since due to the folded weir crest, a three-dimensional flow field is generated, yielding more complex overflow and energy dissipation processes. In this study, CFD simulations of labyrinth weirs were conducted 1) to analyze the discharge coefficients for different discharges to compare the Cd values to literature data and 2) to analyze and improve energy dissipation downstream of the structure. All tests were performed for a structure at laboratory scale with a height of approx. P = 30.5 cm, a ratio of the total crest length to the total width of 4.7, a sidewall angle of 10° and a quarter-round weir crest shape. Tested headwater ratios were 0.089 ≤ HT/P ≤ 0.817. For numerical simulations, FLOW-3D Hydro was employed, solving the RANS equations with use of finite-volume method and RNG k-ε turbulence closure. In terms of discharge capacity, results were compared to data from physical model tests performed at the Utah Water Research Laboratory (Utah State University), emphasizing higher discharge coefficients from CFD than from the physical model. For upstream heads, some discrepancy in the range of ± 1 cm between literature, CFD and physical model tests was identified with a discussion regarding differences included in the manuscript. For downstream energy dissipation, variable tailwater depths were considered to analyze the formation and sweep-out of a hydraulic jump. It was found that even for high discharges, relatively low downstream Froude numbers were obtained due to high energy dissipation involved by the three-dimensional flow between the sidewalls. The effects of some additional energy dissipation devices, e.g. baffle blocks or end sills, were also analyzed. End sills were found to be non-effective. However, baffle blocks with different locations may improve energy dissipation downstream of labyrinth weirs.},
  language  = {en}
}
@inproceedings{CrookstonBung2022,
  author    = {Crookston, Brian M. and Bung, Daniel Bernhard},
  title     = {Application of RGB-D cameras in hydraulic laboratory studies},
  series = {Proceedings of the 39th IAHR World Congress},
  booktitle = {Proceedings of the 39th IAHR World Congress},
  editor    = {Ortega-S{\´a}nchez, Miguel},
  publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)},
  address   = {Madrid},
  isbn      = {978-90-832612-1-8},
  issn      = {2521-7119 (print)},
  doi       = {10.3850/IAHR-39WC252171192022964},
  pages     = {5127 -- 5133},
  year      = {2022},
  abstract  = {Non-intrusive measuring techniques have attained a lot of interest in relation to both hydraulic modeling and prototype applications. Complimenting acoustic techniques, significant progress has been made for the development of new optical methods. Computer vision techniques can help to extract new information, e. g. high-resolution velocity and depth data, from videos captured with relatively inexpensive, consumer-grade cameras. Depth cameras are sensors providing information on the distance between the camera and observed features. Currently, sensors with different working principles are available. Stereoscopic systems reference physical image features (passive system) from two perspectives; in order to enhance the number of features and improve the results, a sensor may also estimate the disparity from a detected light to its original projection (active stereo system). In the current study, the RGB-D camera Intel RealSense D435, working on such stereo vision principle, is used in different, typical hydraulic modeling applications. All tests have been conducted at the Utah Water Research Laboratory. This paper will demonstrate the performance and limitations of the RGB-D sensor, installed as a single camera and as camera arrays, applied to 1) detect the free surface for highly turbulent, aerated hydraulic jumps, for free-falling jets and for an energy dissipation basin downstream of a labyrinth weir and 2) to monitor local scours upstream and downstream of a Piano Key Weir. It is intended to share the authors' experiences with respect to camera settings, calibration, lightning conditions and other requirements in order to promote this useful, easily accessible device. Results will be compared to data from classical instrumentation and the literature. It will be shown that even in difficult application, e. g. the detection of a highly turbulent, fluctuating free-surface, the RGB-D sensor may yield similar accuracy as classical, intrusive probes.},
  language  = {en}
}
@inproceedings{MulsowHuelsenGuetzlaffetal.2023,
  author    = {Mulsow, Niklas A. and H{\"u}lsen, Benjamin and G{\"u}tzlaff, Joel and Spies, Leon and Bresser, Andreas and Dabrowski, Adam and Czupalla, Markus and Kirchner, Frank},
  title     = {Concept and design of an autonomous micro rover for long term lunar exploration},
  series = {Proceedings of the 74th International Astronautical Congress},
  booktitle = {Proceedings of the 74th International Astronautical Congress},
  publisher = {dfki},
  address   = {Saarbr{\"u}cken},
  pages     = {13 Seiten},
  year      = {2023},
  abstract  = {Research on robotic lunar exploration has seen a broad revival, especially since the Google Lunar X-Prize increasingly brought private endeavors into play. This development is supported by national agencies with the aim of enabling long-term lunar infrastructure for in-situ operations and the establishment of a moon village. One challenge for effective exploration missions is developing a compact and lightweight robotic rover to reduce launch costs and open the possibility for secondary payload options. Existing micro rovers for exploration missions are clearly limited by their design for one day of sunlight and their low level of autonomy. For expanding the potential mission applications and range of use, an extension of lifetime could be reached by surviving the lunar night and providing a higher level of autonomy. To address this objective, the paper presents a system design concept for a lightweight micro rover with long-term mission duration capabilities, derived from a multi-day lunar mission scenario at equatorial regions. Technical solution approaches are described, analyzed, and evaluated, with emphasis put on the harmonization of hardware selection due to a strictly limited budget in dimensions and power.},
  language  = {en}
}
@inproceedings{HuelsenMulsowDabrowskietal.2023,
  author    = {H{\"u}lsen, Benjamin and Mulsow, Niklas A. and Dabrowski, Adam and Brinkmann, Wiebke and G{\"u}tzlaff, Joel and Spies, Leon and Czupalla, Markus and Kirchner, Frank},
  title     = {Towards an autonomous micro rover with night survivability for lunar exploration},
  series = {Proceedings of the 74th International Astronautical Congress},
  booktitle = {Proceedings of the 74th International Astronautical Congress},
  publisher = {dfki},
  pages     = {12 Seiten},
  year      = {2023},
  abstract  = {In Europe, efforts are underway to develop key technologies that can be used to explore the Moon and to exploit the resources available. This includes technologies for in-situ resource utilization (ISRU), facilitating the possibility of a future Moon Village. The Moon is the next step for humans and robots to exploit the use of available resources for longer term missions, but also for further exploration of the solar system. A challenge for effective exploration missions is to achieve a compact and lightweight robot to reduce launch costs and open up the possibility of secondary payload options. Current micro rover concepts are primarily designed to last for one day of solar illumination and show a low level of autonomy. Extending the lifetime of the system by enabling survival of the lunar night and implementing a high level of autonomy will significantly increase potential mission applications and the operational range. As a reference mission, the deployment of a micro rover in the equatorial region of the Moon is being considered. An overview of mission parameters and a detailed example mission sequence is given in this paper. The mission parameters are based on an in-depth study of current space agency roadmaps, scientific goals, and upcoming flight opportunities. Furthermore, concepts of the ongoing international micro rover developments are analyzed along with technology solutions identified for survival of lunar nights and a high system autonomy. The results provide a basis of a concise requirements set-up to allow dedicated system developments and qualification measures in the future.},
  language  = {en}
}
@inproceedings{WildCzupallaFoerstner2021,
  author    = {Wild, Dominik and Czupalla, Markus and F{\"o}rstner, Roger},
  title     = {Modeling, prediction and test of additive manufactured integral structures with embedded lattice and phase change material applying Infused Thermal Solutions (ITS)},
  series = {ICES104: Advances in Thermal Control Technology},
  booktitle = {ICES104: Advances in Thermal Control Technology},
  publisher = {Texas Tech University},
  address   = {Lubbock, Tex.},
  pages     = {12 Seiten},
  year      = {2021},
  abstract  = {Infused Thermal Solutions (ITS) introduces a method for passive thermal control to stabilize structural components thermally without active heating and cooling systems, but with phase change material (PCM) for thermal energy storage (TES), in combination with lattice - both embedded in additive manufactured functional structures. In this ITS follow-on paper a thermal model approach and associated predictions are presented, related on the ITS functional breadboards developed at FH Aachen. Predictive TES by PCM is provided by a specially developed ITS PCM subroutine, which is applicable in ESATAN. The subroutine is based on the latent heat storage (LHS) method to numerically embed thermo-physical PCM behavior. Furthermore, a modeling approach is introduced to numerically consider the virtual PCM/lattice nodes within the macro-encapsulated PCM voids of the double wall ITS design. Related on these virtual nodes, in-plane and out-of-plane conductive links are defined. The recent additive manufactured ITS breadboard series are thermally cycled in the thermal vacuum chamber, both with and without embedded PCM. Related on breadboard hardware tests, measurement results are compared with predictions and are subsequently correlated. The results of specific simulations and measurements are presented. Recent predictive results of star tracker analyses are also presented in ICES-2021-106, based on this ITS PCM subroutine.},
  language  = {en}
}
@inproceedings{KohlbergerWildKasperetal.2021,
  author    = {Kohlberger, David-Sharif and Wild, Dominik and Kasper, Stefan and Czupalla, Markus},
  title     = {Modeling and analyses of a thermal passively stabilized LEO/GEO star tracker with embedded phase change material applying the Infused Thermal Solutions (ITS) method},
  series = {ICES202: Satellite, Payload, and Instrument Thermal Control},
  booktitle = {ICES202: Satellite, Payload, and Instrument Thermal Control},
  publisher = {Texas Tech University},
  address   = {Lubbock, Tex.},
  pages     = {12 Seiten},
  year      = {2021},
  abstract  = {Phase change materials offer a way of storing excess heat and releasing it when it is needed. They can be utilized as a method to control thermal behavior without the need for additional energy. This work focuses on exploring the potential of using phase change materials to passively control the thermal behavior of a star tracker by infusing it with a fitting phase change material. Based on the numerical model of the star trackers thermal behavior using ESATAN-TMS without implemented phase change material, a fitting phase change material for selected orbits is chosen and implemented in the thermal model. The altered thermal behavior of the numerical model after the implementation is analyzed for different amounts of the chosen phase change materials using an ESATAN-based subroutine developed by the FH Aachen. The PCM-modelling-subroutine is explained in the paper ICES-2021-110. The results show that an increasing amount of phase change material increasingly damps temperature oscillations. Using an integral part structure some of the mass increase can be compensated.},
  language  = {en}
}
@unpublished{SchmuellingGuetzlaffCzupalla2024,
  author    = {Schm{\"u}lling, Max and G{\"u}tzlaff, Joel and Czupalla, Markus},
  title     = {A thermal simulation environment for moving objects on the lunar surface},
  doi       = {10.21203/rs.3.rs-3902363/v1},
  pages     = {12 Seiten},
  year      = {2024},
  abstract  = {This paper presents a thermal simulation environment for moving objects on the lunar surface. The goal of the thermal simulation environment is to enable the reliable prediction of the temperature development of a given object on the lunar surface by providing the respective heat fluxes for a mission on a given travel path. The user can import any object geometry and freely define the path that the object should travel. Using the path of the object, the relevant lunar surface geometry is imported from a digital elevation model. The relevant parts of the lunar surface are determined based on distance to the defined path. A thermal model of these surface sections is generated, consisting of a porous layer on top and a denser layer below. The object is moved across the lunar surface, and its inclination is adapted depending on the slope of the terrain below it. Finally, a transient thermal analysis of the object and its environment is performed at several positions on its path and the results are visualized. The paper introduces details on the thermal modeling of the lunar surface, as well as its verification. Furthermore, the structure of the created software is presented. The robustness of the environment is verified with the help of sensitivity studies and possible improvements are presented.},
  language  = {en}
}
@article{WildSchrezenmeierCzupallaetal.2020,
  author    = {Wild, Dominik and Schrezenmeier, Johannes and Czupalla, Markus and F{\"o}rstner, Roger},
  title     = {Thermal Characterization of additive manufactured Integral Structures for Phase Change Applications},
  series = {2020 International Conference on Environmental Systems},
  journal   = {2020 International Conference on Environmental Systems},
  publisher = {Texas Tech University},
  year      = {2020},
  abstract  = {"Infused Thermal Solutions" (ITS) introduces a method for passive thermal control to stabilize structural components thermally without active heating and cooling systems, by using phase change material (PCM) in combination with lattice - both embedded into an additive manufactured integral structure. The technology is currently under development. This paper presents the results of the thermal property measurements performed on additive manufactured ITS breadboards. Within the breadboard campaigns key characteristics of the additive manufactured specimens were derived: Mechanical parameters: specimen impermeability, minimum wall thickness, lattice structure, subsequent heat treatment. Thermal properties: thermo-optical surface properties of the additive manufactured raw material, thermal conductivity and specific heat capacity measurements. As a conclusion the paper introduces an overview of potential ITS hardware applications, expected to increase the thermal performance.},
  language  = {en}
}
@article{SchopenNarayanBeckmannetal.2024,
  author    = {Schopen, Oliver and Narayan, Sriram and Beckmann, Marvin and Najmi, Aezid-Ul-Hassan and Esch, Thomas and Shabani, Bahman},
  title     = {An EIS approach to quantify the effects of inlet air relative humidity on the performance of proton exchange membrane fuel cells: a pathway to developing a novel fault diagnostic method},
  series = {International Journal of Hydrogen Energy},
  volume    = {58},
  journal   = {International Journal of Hydrogen Energy},
  number    = {8},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0360-3199 (print)},
  issn      = {1879-3487 (online)},
  doi       = {10.1016/j.ijhydene.2024.01.218},
  pages     = {1302 -- 1315},
  year      = {2024},
  abstract  = {In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 \% and the cathode side charge transfer resistance decreases by 23 \% after increasing the humidity from 30 \% to 85 \%, while the results of static operation also show an increase of ∼2.2 \% in the voltage output after increasing the relative humidity from 30 \% to 85 \%. In dynamic operation, visible drying effects occur at < 50 \% relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators.},
  language  = {en}
}
@inproceedings{VeettilRakshitSchopenetal.2022,
  author    = {Veettil, Yadu Krishna Morassery and Rakshit, Shantam and Schopen, Oliver and Kemper, Hans and Esch, Thomas and Shabani, Bahman},
  title     = {Automated Control System Strategies to Ensure Safety of PEM Fuel Cells Using Kalman Filters},
  series = {Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia},
  booktitle = {Proceedings of the 7th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2021), Melaka, Malaysia},
  editor    = {Bin Abdollah, Mohd Fadzli and Amiruddin, Hilmi and Singh, Amrik Singh Phuman and Munir, Fudhail Abdul and Ibrahim, Asriana},
  publisher = {Springer Nature},
  address   = {Singapore},
  isbn      = {978-981-19-3178-9},
  issn      = {2195-4356},
  doi       = {10.1007/978-981-19-3179-6_55},
  pages     = {296 -- 299},
  year      = {2022},
  abstract  = {Having well-defined control strategies for fuel cells, that can efficiently detect errors and take corrective action is critically important for safety in all applications, and especially so in aviation. The algorithms not only ensure operator safety by monitoring the fuel cell and connected components, but also contribute to extending the health of the fuel cell, its durability and safe operation over its lifetime. While sensors are used to provide peripheral data surrounding the fuel cell, the internal states of the fuel cell cannot be directly measured. To overcome this restriction, Kalman Filter has been implemented as an internal state observer. Other safety conditions are evaluated using real-time data from every connected sensor and corrective actions automatically take place to ensure safety. The algorithms discussed in this paper have been validated thorough Model-in-the-Loop (MiL) tests as well as practical validation at a dedicated test bench.},
  language  = {en}
}
@inproceedings{SchopenKemperEsch2021,
  author    = {Schopen, Oliver and Kemper, Hans and Esch, Thomas},
  title     = {Development of a comparison methodology and evaluation matrix for electrically driven compressors in ICE and FC},
  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},
  publisher = {FH Joanneum},
  address   = {Graz},
  isbn      = {978-3-902103-94-9},
  pages     = {45 -- 46},
  year      = {2021},
  abstract  = {In addition to electromobility and alternative drive systems, a focus is set on electrically driven compressors (EDC), with a high potential for increasing the efficiency of internal combustion engines (ICE) and fuel cells [01]. The primary objective is to increase the ICE torque, provided independently of the ICE speed by compressing the intake air and consequently the ICE filling level supported by the compressor. For operation independent from the ICE speed, the EDC compressor is decoupled from the turbine by using an electric compressor motor (CM) instead of the turbine. ICE performances can be increased by the use of EDC where individual compressor parameters are adapted to the respective application area [02] [03]. This task contains great challenges, increased by demands with regard to pollutant reduction while maintaining constant performance and reduced fuel consumption. The FH-Aachen is equipped with an EDC test bench which enables EDC-investigations in various configurations and operating modes. Characteristic properties of different compressors can be determined, which build the basis for a comparison methodology. Subject of this project is the development of a comparison methodology for EDC with an associated evaluation method and a defined overall evaluation method. For the application of this comparison methodology, corresponding series of measurements are carried out on the EDC test bench using an appropriate test device.},
  language  = {en}
}
@article{SchopenShahEschetal.2024,
  author    = {Schopen, Oliver and Shah, Neel and Esch, Thomas and Shabani, Bahman},
  title     = {Critical quantitative evaluation of integrated health management methods for fuel cell applications},
  series = {International Journal of Hydrogen Energy},
  volume    = {70},
  journal   = {International Journal of Hydrogen Energy},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0360-3199},
  doi       = {10.1016/j.ijhydene.2024.05.156},
  pages     = {370 -- 388},
  year      = {2024},
  abstract  = {Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system.},
  language  = {en}
}
@inproceedings{SchopenShabaniEschetal.2022,
  author    = {Schopen, Oliver and Shabani, Bahman and Esch, Thomas and Kemper, Hans and Shah, Neel},
  title     = {Quantitative evaluation of health management designs for fuel cell systems in transport vehicles},
  series = {2nd UNITED-SAIG International Conference Proceedings},
  booktitle = {2nd UNITED-SAIG International Conference Proceedings},
  editor    = {Rahim, S.A. and As'arry, A. and Zuhri, M.Y.M. and Harmin, M.Y. and Rezali, K.A.M. and Hairuddin, A.A.},
  pages     = {1 -- 3},
  year      = {2022},
  abstract  = {Focusing on transport vehicles, mainly with regard to aviation applications, this paper presents compilation and subsequent quantitative evaluation of methods aimed at building an optimum integrated health management solution for fuel cell systems. The methods are divided into two different main types and compiled in a related scheme. Furthermore, different methods are analysed and evaluated based on parameters specific to the aviation context of this study. Finally, the most suitable method for use in fuel cell health management systems is identified and its performance and suitability is quantified.},
  language  = {en}
}
@inproceedings{StarkRiepingEsch2023,
  author    = {Stark, Ralf and Rieping, Carla and Esch, Thomas},
  title     = {The impact of guide tubes on flow separation in rocket nozzles},
  series = {Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS},
  booktitle = {Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS},
  pages     = {8 Seiten},
  year      = {2023},
  abstract  = {Rocket engine test facilities and launch pads are typically equipped with a guide tube. Its purpose is to ensure the controlled and safe routing of the hot exhaust gases. In addition, the guide tube induces a suction that effects the nozzle flow, namely the flow separation during transient start-up and shut-down of the engine. A cold flow subscale nozzle in combination with a set of guide tubes was studied experimentally to determine the main influencing parameters.},
  language  = {en}
}
@inproceedings{StarkBartelDitscheetal.2023,
  author    = {Stark, Ralf and Bartel, Sebastian and Ditsche, Florian and Esch, Thomas},
  title     = {Design study of a 30kN LOX/LCH4 aerospike rocket engine for lunar lander application},
  series = {Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS},
  booktitle = {Aerospace Europe Conference 2023 - 10th EUCASS - 9th CEAS},
  pages     = {9 Seiten},
  year      = {2023},
  abstract  = {Based on lunar lander concept EL3, various LOX/CH4 aerospike engines were studied. A distinction was made between single and cluster configurations as well as ideal and non-ideal contour concepts. It could be shown that non-ideal aerospike engines promise a significant payload gain.},
  language  = {en}
}
@misc{RothTippkoetter2016,
  author    = {Roth, J. and Tippk{\"o}tter, Nils},
  title     = {New Approach for Enzymatic Hydrolysis of Lignocellulose with Selective Diffusion Separation of the Monosaccharide Products},
  series = {Chemie Ingenieur Technik},
  volume    = {88},
  journal   = {Chemie Ingenieur Technik},
  number    = {9},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0009-286X},
  doi       = {10.1002/cite.201650301},
  pages     = {1237},
  year      = {2016},
  abstract  = {Enzymatic hydrolysis of lignocellulosic material plays an important role in the classical biorefinery approach. Apart from the pretreatment of the raw material, hydrolysis is the basis for the conversion of the cellulose and hemicellulose fraction into fermentable sugars. After hydrolysis, usually a solid-liquid separation takes place, in order to separate the residual plant material from the sugar-rich fraction, which can be subsequently used in a fermentation step. In order to factor out the separation step, the usage of in alginate immobilized crude cellulose fiber beads (CFBs) were evaluated. Pretreated cellulose fibers are incorporated in an alginate matrix together with the relevant enzymes. In doing so, sugars diffuse trough the alginate matrix, allowing a simplified delivery into the surrounding fluid. This again reduces product inhibition of the glucose on the enzyme catalysts. By means of standardized bead production the hydrolysis in lab scale was possible. First results show that liberation of glucose and xylose is possible, allowing a maximum total sugar yield of 75 \%.},
  language  = {en}
}
@article{AyalaHarrisKleefeld2024,
  author    = {Ayala, Rafael Ceja and Harris, Isaac and Kleefeld, Andreas},
  title     = {Direct sampling method via Landweber iteration for an absorbing scatterer with a conductive boundary},
  series = {Inverse Problems and Imaging},
  volume    = {18},
  journal   = {Inverse Problems and Imaging},
  number    = {3},
  publisher = {AIMS},
  address   = {Springfield},
  issn      = {1930-8337},
  doi       = {10.3934/ipi.2023051},
  pages     = {708 -- 729},
  year      = {2024},
  abstract  = {In this paper, we consider the inverse shape problem of recovering isotropic scatterers with a conductive boundary condition. Here, we assume that the measured far-field data is known at a fixed wave number. Motivated by recent work, we study a new direct sampling indicator based on the Landweber iteration and the factorization method. Therefore, we prove the connection between these reconstruction methods. The method studied here falls under the category of qualitative reconstruction methods where an imaging function is used to recover the absorbing scatterer. We prove stability of our new imaging function as well as derive a discrepancy principle for recovering the regularization parameter. The theoretical results are verified with numerical examples to show how the reconstruction performs by the new Landweber direct sampling method.},
  language  = {en}
}
@inproceedings{KahraBreussKleefeldetal.2024,
  author    = {Kahra, Marvin and Breuß, Michael and Kleefeld, Andreas and Welk, Martin},
  title     = {An Approach to Colour Morphological Supremum Formation Using the LogSumExp Approximation},
  series = {Discrete Geometry and Mathematical Morphology},
  booktitle = {Discrete Geometry and Mathematical Morphology},
  editor    = {Brunetti, Sara and Frosini, Andrea and Rinaldi, Simone},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-031-57793-2},
  doi       = {10.1007/978-3-031-57793-2_25},
  pages     = {325 -- 337},
  year      = {2024},
  abstract  = {Mathematical morphology is a part of image processing that has proven to be fruitful for numerous applications. Two main operations in mathematical morphology are dilation and erosion. These are based on the construction of a supremum or infimum with respect to an order over the tonal range in a certain section of the image. The tonal ordering can easily be realised in grey-scale morphology, and some morphological methods have been proposed for colour morphology. However, all of these have certain limitations. In this paper we present a novel approach to colour morphology extending upon previous work in the field based on the Loewner order. We propose to consider an approximation of the supremum by means of a log-sum exponentiation introduced by Maslov. We apply this to the embedding of an RGB image in a field of symmetric 2x2 matrices. In this way we obtain nearly isotropic matrices representing colours and the structural advantage of transitivity. In numerical experiments we highlight some remarkable properties of the proposed approach.},
  language  = {en}
}
@incollection{PieronekKleefeld2019,
  author    = {Pieronek, Lukas and Kleefeld, Andreas},
  title     = {The Method of Fundamental Solutions for Computing Interior Transmission Eigenvalues of Inhomogeneous Media},
  series = {Integral Methods in Science and Engineering: Analytic Treatment and Numerical Approximations},
  booktitle = {Integral Methods in Science and Engineering: Analytic Treatment and Numerical Approximations},
  editor    = {Constanda, Christian and Harris, Paul},
  publisher = {Birkh{\"a}user},
  address   = {Cham},
  isbn      = {978-3-030-16077-7},
  doi       = {10.1007/978-3-030-16077-7_28},
  pages     = {353 -- 365},
  year      = {2019},
  abstract  = {The method of fundamental solutions is applied to the approximate computation of interior transmission eigenvalues for a special class of inhomogeneous media in two dimensions. We give a short approximation analysis accompanied with numerical results that clearly prove practical convenience of our alternative approach.},
  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}
}
@incollection{AbeleKleefeld2020,
  author    = {Abele, Daniel and Kleefeld, Andreas},
  title     = {New Numerical Results for the Optimization of Neumann Eigenvalues},
  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 (Print)},
  doi       = {10.1007/978-3-030-48186-5_1},
  pages     = {1 -- 20},
  year      = {2020},
  abstract  = {We present new numerical results for shape optimization problems of interior Neumann eigenvalues. This field is not well understood from a theoretical standpoint. The existence of shape maximizers is not proven beyond the first two eigenvalues, so we study the problem numerically. We describe a method to compute the eigenvalues for a given shape that combines the boundary element method with an algorithm for nonlinear eigenvalues. As numerical optimization requires many such evaluations, we put a focus on the efficiency of the method and the implemented routine. The method is well suited for parallelization. Using the resulting fast routines and a specialized parametrization of the shapes, we found improved maxima for several eigenvalues.},
  language  = {en}
}
@inproceedings{VladovaUllrichSultanowetal.2023,
  author    = {Vladova, Gergana and Ullrich, Andr{\´e} and Sultanow, Eldar and Tobolla, Marinho and Sebrak, Sebastian and Czarnecki, Christian and Brockmann, Carsten},
  title     = {Visual analytics for knowledge management},
  series = {INFORMATIK 2023 - Designing Futures: Zuk{\"u}nfte gestalten},
  booktitle = {INFORMATIK 2023 - Designing Futures: Zuk{\"u}nfte gestalten},
  publisher = {GI - Gesellschaft f{\"u}r Informatik},
  address   = {Bonn},
  isbn      = {978-3-88579-731-9},
  issn      = {1617-5468},
  doi       = {10.18420/inf2023_187},
  pages     = {1851 -- 1870},
  year      = {2023},
  abstract  = {The management of knowledge in organizations considers both established long-term processes and cooperation in agile project teams. Since knowledge can be both tacit and explicit, its transfer from the individual to the organizational knowledge base poses a challenge in organizations. This challenge increases when the fluctuation of knowledge carriers is exceptionally high. Especially in large projects in which external consultants are involved, there is a risk that critical, company-relevant knowledge generated in the project will leave the company with the external knowledge carrier and thus be lost. In this paper, we show the advantages of an early warning system for knowledge management to avoid this loss. In particular, the potential of visual analytics in the context of knowledge management systems is presented and discussed. We present a project for the development of a business-critical software system and discuss the first implementations and results.},
  language  = {en}
}
@incollection{SchultLosseCzarneckietal.2023,
  author    = {Schult, Prince Garcia and Losse, Ann-Kathrin and Czarnecki, Christian and Sultanow, Eldar},
  title     = {Proposing a Framework to address the Sustainable Development Goals},
  series = {EnviroInfo 2023},
  booktitle = {EnviroInfo 2023},
  publisher = {GI - Gesellschaft f{\"u}r Informatik},
  address   = {Bonn},
  isbn      = {978-3-88579-736-4},
  issn      = {1617-5468},
  doi       = {10.18420/env2023-022},
  pages     = {243 -- 249},
  year      = {2023},
  abstract  = {Reducing poverty, protecting the planet, and improving life on earth for everyone are the essential goals of the "2030 Agenda for Sustainable Development"committed by the United Nations (UN). Achieving those goals will require technological innovation as well as their implementation in almost all areas of our business and day-to-day life. This paper proposes a high-level framework that collects and structures different uses cases addressing the goals defined by the UN. Hence, it contributes to the discussion by proposing technical innovations that can be used to achieve those goals. As an example, the goal "Climate Action{\"i}s discussed in detail by describing use cases related to tackling biodiversity loss in order to conservate ecosystems.},
  language  = {en}
}
@phdthesis{Bung2023,
  author    = {Bung, Daniel Bernhard},
  title     = {Imaging techniques for investigation of free-surface flows in hydraulic laboratories},
  doi       = {10.25926/BUW/0-172},
  pages     = {XXIII, 218 Seiten},
  year      = {2023},
  abstract  = {This thesis aims at the presentation and discussion of well-accepted and new imaging techniques applied to different types of flow in common hydraulic engineering environments. All studies are conducted in laboratory conditions and focus on flow depth and velocity measurements. Investigated flows cover a wide range of complexity, e.g. propagation of waves, dam-break flows, slightly and fully aerated spillway flows as well as highly turbulent hydraulic jumps. Newimagingmethods are compared to different types of sensorswhich are frequently employed in contemporary laboratory studies. This classical instrumentation as well as the general concept of hydraulic modeling is introduced to give an overview on experimental methods. Flow depths are commonly measured by means of ultrasonic sensors, also known as acoustic displacement sensors. These sensors may provide accurate data with high sample rates in case of simple flow conditions, e.g. low-turbulent clear water flows. However, with increasing turbulence, higher uncertainty must be considered. Moreover, ultrasonic sensors can provide point data only, while the relatively large acoustic beam footprint may lead to another source of uncertainty in case of relatively short, highly turbulent surface fluctuations (ripples) or free-surface air-water flows. Analysis of turbulent length and time scales of surface fluctuations from point measurements is also difficult. Imaging techniques with different dimensionality, however, may close this gap. It is shown in this thesis that edge detection methods (known from computer vision) may be used for two-dimensional free-surface extraction (i.e. from images taken through transparant sidewalls in laboratory flumes). Another opportunity in hydraulic laboratory studies comes with the application of stereo vision. Low-cost RGB-D sensors can be used to gather instantaneous, three-dimensional free-surface elevations, even in flows with very high complexity (e.g. aerated hydraulic jumps). It will be shown that the uncertainty of these methods is of similar order as for classical instruments. Particle Image Velocimetry (PIV) is a well-accepted and widespread imaging technique for velocity determination in laboratory conditions. In combination with high-speed cameras, PIV can give time-resolved velocity fields in 2D/3D or even as volumetric flow fields. PIV is based on a cross-correlation technique applied to small subimages of seeded flows. The minimum size of these subimages defines the maximum spatial resolution of resulting velocity fields. A derivative of PIV for aerated flows is also available, i.e. the so-called Bubble Image Velocimetry (BIV). This thesis emphasizes the capacities and limitations of both methods, using relatively simple setups with halogen and LED illuminations. It will be demonstrated that PIV/BIV images may also be processed by means of Optical Flow (OF) techniques. OF is another method originating from the computer vision discipline, based on the assumption of image brightness conservation within a sequence of images. The Horn-Schunck approach, which has been first employed to hydraulic engineering problems in the studies presented herein, yields dense velocity fields, i.e. pixelwise velocity data. As discussed hereinafter, the accuracy of OF competes well with PIV for clear-water flows and even improves results (compared to BIV) for aerated flow conditions. In order to independently benchmark the OF approach, synthetic images with defined turbulence intensitiy are used. Computer vision offers new opportunities that may help to improve the understanding of fluid mechanics and fluid-structure interactions in laboratory investigations. In prototype environments, it can be employed for obstacle detection (e.g. identification of potential fish migration corridors) and recognition (e.g. fish species for monitoring in a fishway) or surface reconstruction (e.g. inspection of hydraulic structures). It can thus be expected that applications to hydraulic engineering problems will develop rapidly in near future. Current methods have not been developed for fluids in motion. Systematic future developments are needed to improve the results in such difficult conditions.},
  language  = {en}
}
@article{MuesgenanntKoersMcNeilRadchenkoetal.2023,
  author    = {Mues genannt Koers, Lucas and McNeil, S. W. and Radchenko, V. and Paulßen, Elisabeth and Hoehr, Cornelia},
  title     = {Production of Co-58m in a siphon-style liquid target on a medical cyclotron},
  volume    = {195},
  number    = {Art. 110734},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0969-8043},
  doi       = {10.1016/j.apradiso.2023.110734},
  year      = {2023},
  abstract  = {We present the production of 58mCo on a small, 13 MeV medical cyclotron utilizing a siphon style liquid target system. Different concentrated iron(III)-nitrate solutions of natural isotopic distribution were irradiated at varying initial pressures and subsequently separated by solid phase extraction chromatography. The radio cobalt (58m/gCo and 56Co) was successfully produced with saturation activities of (0.35 ± 0.03) MBq μA-1 for 58mCo with a separation recovery of (75 ± 2) \% of cobalt after one separation step utilizing LN-resin.},
  language  = {en}
}
@article{MuesgenanntKoersPrevostPaulssenetal.2023,
  author    = {Mues genannt Koers, Lucas and Prevost, David and Paulßen, Elisabeth and Hoehr, Cornelia},
  title     = {Density reduction effects on the production of [11C]CO2 in Nb-body targets on a medical cyclotron},
  volume    = {199},
  number    = {Art. 110911},
  publisher = {Elsevier},
  address   = {Amsterdam},
  doi       = {10.1016/j.apradiso.2023.110911},
  year      = {2023},
  abstract  = {Medical isotope production of 11C is commonly performed in gaseous targets. The power deposition of the proton beam during the irradiation decreases the target density due to thermodynamic mixing and can cause an increase of penetration depth and divergence of the proton beam. In order to investigate the difference how the target-body length influences the operation conditions and the production yield, a 12 cm and a 22 cm Nb-target body containing N2/O2 gas were irradiated using a 13 MeV proton cyclotron. It was found that the density reduction has a large influence on the pressure rise during irradiation and the achievable radioactive yield. The saturation activity of [11C]CO2 for the long target (0.083 Ci/μA) is about 10\% higher than in the short target geometry (0.075 Ci/μA).},
  language  = {en}
}
@article{DroopChenRadfordetal.2023,
  author    = {Droop, Philipp and Chen, Shaohuang and Radford, Melissa J. and Paulßen, Elisabeth and Gates, Byron D. and Reilly, Raymond M. and Radchenko, Valery and Hoehr, Cornelia},
  title     = {Synthesis of 197m/gHg labelled gold nanoparticles for targeted radionuclide therapy},
  series = {Radiochimica Acta},
  volume    = {111},
  journal   = {Radiochimica Acta},
  number    = {10},
  publisher = {De Gruyter},
  address   = {Berlin [u.a.]},
  issn      = {2193-3405},
  doi       = {10.1515/ract-2023-0144},
  pages     = {773 -- 779},
  year      = {2023},
  abstract  = {Meitner-Auger-electron emitters have a promising potential for targeted radionuclide therapy of cancer because of their short range and the high linear energy transfer of Meitner-Auger-electrons (MAE). One promising MAE candidate is 197m/gHg with its half-life of 23.8 h and 64.1 h, respectively, and high MAE yield. Gold nanoparticles (AuNPs) that are labelled with 197m/gHg could be a helpful tool for radiation treatment of glioblastoma multiforme when infused into the surgical cavity after resection to prevent recurrence. To produce such AuNPs, 197m/gHg was embedded into pristine AuNPs. Two different syntheses were tested starting from irradiated gold containing trace amounts of 197m/gHg. When sodium citrate was used as reducing agent, no 197m/gHg labelled AuNPs were formed, but with tannic acid, 197m/gHg labeled AuNPs were produced. The method was optimized by neutralizing the pH (pH = 7) of the Au/197m/gHg solution, which led to labelled AuNPs with a size of 12.3 ± 2.0 nm as measured by transmission electron microscopy. The labelled AuNPs had a concentration of 50 μg (gold)/mL with an activity of 151 ± 93 kBq/mL (197gHg, time corrected to the end of bombardment).},
  language  = {en}
}
@inproceedings{BergmannGraebenerWildetal.2019,
  author    = {Bergmann, Kevin and Gr{\"a}bener, Josefine and Wild, Dominik and Ulfers, H. and Czupalla, Markus},
  title     = {Study on thermal stabilization of a GEO-stationary telescope baffling system by integral application of phase change material},
  series = {International Conference on Environmental Systems},
  booktitle = {International Conference on Environmental Systems},
  pages     = {1 -- 14},
  year      = {2019},
  abstract  = {The utilization of phase change material (PCM) for latent heat storage and thermal control of spacecraft has been demonstrated in the past in few missions only. One limiting factor was the fact that all concepts developed so far envisioned the PCM to be applied as an additional capacitor, encapsulated in its own housing, leading to mass, efficiency and accommodation challenges. Recently, the application of PCM within the scan cavity of a GEOS type satellite has been suggested, in order to tackle thermal issues due to direct sun intrusion (Choi, M., 2014). However, the application of PCM in such complex mechanical structures is extremely challenging. A new concept to tackle this issue is currently under development at the FH Aachen University of Applied Sciences. The concept "Infused Thermal Solutions (ITS)" is based on the idea to 3D print metallic structures in their regular functional shape, but double walled with internal lattice support structures, allowing the infusion of a PCM layer directly into the voids and eliminating the need for additional parts and interfaces. Together with OHB System, FH Aachen theoretically studied the application of this technology to the Meteosat Third Generation (MTG) Infra-Red Sounder (IRS) instrument. The study focuses on the scan cavity and entrance baffling assembly (EBA) of the IRS. It consists of thermal analyses, 3D-redesign and bread boarding of a scaled and PCM infused EBA version. In the thermal design of the alternative EBA, PCM was applied directly into the EBA, simulating the worst hot case sun intrusion of the mission. By applying 4kg of PCM (to a 60kg baffle) the EBA temperature excursions during sun intrusion were limited from 140K to 30K, leading to a significant thermo-opto-elastic performance gain. This paper introduces the ITS concept development status.},
  language  = {en}
}
@misc{GamgamiCzupallaGarciaetal.2016,
  author    = {Gamgami, Farid and Czupalla, Markus and Garcia, Antonio and Agnolon, David},
  title     = {From planetary transits to spacecraft design: achieving PLATO's pointing performance},
  series = {A7. Symposium on technological Requirement for future space astronomy and solar-system science missions},
  journal   = {A7. Symposium on technological Requirement for future space astronomy and solar-system science missions},
  year      = {2016},
  abstract  = {In the last decades, several hundred exoplanets could be detected thanks to space-based observatories, namely CNES' COROT and NASA's Kepler. To expand this quest ESA plans to launch CHEOPS as the f irst small class mission in the cosmic visions program (S1) and PLATO as the 3rd medium class mission, so called M3 . PLATO's primary objective is the detection of Earth like Exoplanets orbiting solar type stars in the habitable zone and characterisation of their bulk properties. This is possible by precise lightcurve measurement via 34 cameras. That said it becomes obvious that accurate pointing is key to achieve the required signal to noise ratio for positive transit detection. The paper will start with a comprehensive overview of PLATO's mission objectives and mission architecture. Hereafter, special focus will be devoted to PLATO's pointing requirements. Understanding the very nature of PLATO's pointing requirements is essential to derive a design baseline to achieve the required performance. The PLATO frequency domain is of particular interest, ranging from 40 mHz to 3 Hz. Due to the very different time-scales involved, the spectral pointing requirement is decomposed into a high frequency part dominated by the attitude control system and the low frequency part dominated by the thermo-elastic properties of the spacecraft's configuration. Both pose stringent constraints on the overall design as well as technology properties to comply with the derived requirements and thus assure a successful mission.},
  language  = {en}
}
@inproceedings{BungLangohrWaldenberger2023,
  author    = {Bung, Daniel Bernhard and Langohr, Phillip and Waldenberger, Lisa},
  title     = {Influence of cycle number in CFD studies of labyrinth weirs},
  series = {Proceedings of the 40th IAHR World Congress (Vienna, 2023)},
  booktitle = {Proceedings of the 40th IAHR World Congress (Vienna, 2023)},
  editor    = {Habersack, Helmut and Tritthart, Michael},
  publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)},
  address   = {Madrid},
  isbn      = {978-90-833476-1-5},
  issn      = {L 2521-7119 (online)},
  doi       = {10.3850/978-90-833476-1-5_iahr40wc-p0531-cd},
  year      = {2023},
  abstract  = {The major advantage of labyrinth weirs over linear weirs is hydraulic efficiency. In hydraulic modeling efforts, this strength contrasts with limited pump capacity as well as limited computational power for CFD simulations. For the latter, reducing the number of investigated cycles can significantly reduce necessary computational time. In this study, a labyrinth weir with different cycle numbers was investigated. The simulations were conducted in FLOW-3D HYDRO as a Large Eddy Simulation. With a mean deviation of 1.75 \% between simulated discharge coefficients and literature design equations, a reasonable agreement was found. For downstream conditions, overall consistent results were observed as well. However, the orientation of labyrinth weirs with a single cycle should be chosen carefully under consideration of the individual research purpose.},
  language  = {en}
}
@misc{EcclestonDrummondMiddletonetal.2020,
  author    = {Eccleston, Paul and Drummond, Rachel and Middleton, Kevin and Bishop, Georgia and Caldwell, Andrew and Desjonqueres, Lucile and Tosh, Ian and Cann, Nick and Crook, Martin and Hills, Matthew and Pearson, Chris and Simpson, Caroline and Stamper, Richard and Tinetti, Giovanna and Pascale, Enzo and Swain, Mark and Holmes, Warren A. and Wong, Andre and Puig, Ludovic and Pilbratt, G{\"o}ran and Linder, Martin and Boudin, Nathalie and Ertel, Hanno and Gambicorti, Lisa and Halain, Jean-Philippe and Pace, Emanuele and Vilardell, Francesc and G{\´o}mez, Jos{\´e} M. and Colom{\´e}, Josep and Amiaux, J{\´e}r{\^o}me and Cara, Christophe and Berthe, Michel and Moreau, Vincent and Morgante, Gianluca and Malaguti, Giuseppe and Alonso, Gustavo and {\´A}lvarez, Javier P. and Ollivier, Marc and Philippon, Anne and Hellin, Marie-Laure and Roose, Steve and Frericks, Martin and Krijger, Matthijs and Rataj, Miroslaw and Wawer, Piotr and Skup, Konrad and Sobiecki, Mateusz and Christian Jessen, Niels and M{\o}ller Pedersen, S{\o}ren and Hargrave, Peter and Griffin, Matt and Ottensamer, Roland and Hunt, Thomas and Rust, Duncan and Saleh, Aymen and Winter, Berend and Focardi, Mauro and Da Deppo, Vania and Zuppella, Paola and Czupalla, Markus},
  title     = {The ARIEL payload: A technical overview},
  series = {Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave},
  volume    = {11443},
  journal   = {Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave},
  editor    = {Lystrup, Makenzie and Perrin, Marshall D. and Batalha, Natalie and Siegler, Nicholas and Tong, Edward C.},
  publisher = {SPIE},
  address   = {Washington},
  doi       = {10.1117/12.2561478},
  pages     = {114430Z},
  year      = {2020},
  abstract  = {The Atmospheric Remote-Sensing Infrared Exoplanet Large-survey, ARIEL, has been selected to be the next (M4) medium class space mission in the ESA Cosmic Vision programme. From launch in 2028, and during the following 4 years of operation, ARIEL will perform precise spectroscopy of the atmospheres of ~1000 known transiting exoplanets using its metre-class telescope. A three-band photometer and three spectrometers cover the 0.5 µm to 7.8 µm region of the electromagnetic spectrum. This paper gives an overview of the mission payload, including the telescope assembly, the FGS (Fine Guidance System) - which provides both pointing information to the spacecraft and scientific photometry and low-resolution spectrometer data, the ARIEL InfraRed Spectrometer (AIRS), and other payload infrastructure such as the warm electronics, structures and cryogenic cooling systems.},
  language  = {en}
}
@misc{ReiswichBrandtCzupalla2019,
  author    = {Reiswich, Martin and Brandt, Hannes and Czupalla, Markus},
  title     = {Passive thermal control by integration of phase change material into additively manufactured structures},
  series = {E2. 47th Student conference},
  journal   = {E2. 47th Student conference},
  year      = {2019},
  abstract  = {Optical Instruments require an extremely stable thermal surrounding to prevent loss of data quality by misalignments of the instrument components resulting from material deformation due to temperature f luctuations (e.g. from solar intrusion). Phase Change Material (PCM) can be applied as a thermal damper to achieve a more uniform temperature distribution. The challenge of this method is, among others, the integration of PCM into affected areas. If correctly designed, incoming heat is latently absorbed during phase change of the PCM, i.e. the temperature of a structure remains almost constant. In a cold phase, the heat during phase change is released again latently until the PCM returns to its original state of aggregation. Thus, the structure is thermally stabilized. At FH Aachen- University of Applied Sciences research is conducted to apply PCM directly into the structures of affected components (baffles, optical benches, electronic boxes, etc.). Through the application of Additive Manufacturing, the necessary voids are directly printed into these structures and filled later with PCM. Additive Manufacturing enables complex structures that would not have been possible with conservative manufacturing methods. A corresponding Breadboard was developed and manufactured by Selective Laser Melting (SLM). The current state of research includes the handling and analysis of the Breadboard, tests and a correlation of the thermal model. The results have shown analytically and practically that it is possible to use PCM as an integral part of the structure as a thermal damper. The results serve as a basis for the further development of the technology, which should maximize performance and enable the integration of PCM into much more complex structures.},
  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}
}
@misc{MayntzKeimerTegtmeyeretal.2021,
  author    = {Mayntz, Joscha and Keimer, Jona and Tegtmeyer, Philipp and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham},
  title     = {Aerodynamic Investigation on Efficient Inflight Transition of a Propeller from Propulsion to Regeneration Mode},
  series = {AIAA SCITECH 2022 Forum},
  journal   = {AIAA SCITECH 2022 Forum},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2022-0546},
  year      = {2021},
  abstract  = {This paper discusses a new way of inflight power regeneration for electric or hybrid-electric driven general aviation aircraft with one powertrain for both configurations. Three different approaches for the shift from propulsion to regeneration mode are analyzed. Numerical cal-culation and wind tunnel results are compared and show the highest regeneration potential for the "Windmill" approach, where the propeller blades are flipped, and rotation is reversed. A combination of all regeneration approaches for a realistic flight mission is discussed.},
  language  = {en}
}
@misc{KeimerGirbigMayntzetal.2022,
  author    = {Keimer, Jona and Girbig, Leo and Mayntz, Joscha and Tegtmeyer, Philipp and Wendland, Frederik and Dahman, Peter and Fisher, Alex and Dorrington, Graham},
  title     = {Flight mission optimization for eco-efficiency in consideration of electric regeneration and atmospheric conditions},
  series = {AIAA AVIATION 2022 Forum},
  journal   = {AIAA AVIATION 2022 Forum},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2022-4118},
  year      = {2022},
  abstract  = {The development and operation of hybrid or purely electrically powered aircraft in regional air mobility is a significant challenge for the entire aviation sector. This technology is expected to lead to substantial advances in flight performance, energy efficiency, reliability, safety, noise reduction, and exhaust emissions. Nevertheless, any consumed energy results in heat or carbon dioxide emissions and limited electric energy storage capabilities suppress commercial use. Therefore, the significant challenges to achieving eco-efficient aviation are increased aircraft efficiency, the development of new energy storage technologies, and the optimization of flight operations. Two major approaches for higher eco-efficiency are identified: The first one, is to take horizontal and vertical atmospheric motion phenomena into account. Where, in particular, atmospheric waves hold exciting potential. The second one is the use of the regeneration ability of electric aircraft. The fusion of both strategies is expected to improve efficiency. The objective is to reduce energy consumption during flight while not neglecting commercial usability and convenient flight characteristics. Therefore, an optimized control problem based on a general aviation class aircraft has to be developed and validated by flight experiments. The formulated approach enables a development of detailed knowledge of the potential and limitations of optimizing flight missions, considering the capability of regeneration and atmospheric influences to increase efficiency and range.},
  language  = {en}
}
@article{UlmerBraunChengetal.2023,
  author    = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg},
  title     = {A human factors-aware assistance system in manufacturing based on gamification and hardware modularisation},
  series = {International Journal of Production Research},
  journal   = {International Journal of Production Research},
  publisher = {Taylor \& Francis},
  issn      = {0020-7543 (Print)},
  doi       = {10.1080/00207543.2023.2166140},
  year      = {2023},
  abstract  = {Assistance systems have been widely adopted in the manufacturing sector to facilitate various processes and tasks in production environments. However, existing systems are mostly equipped with rigid functional logic and do not provide individual user experiences or adapt to their capabilities. This work integrates human factors in assistance systems by adjusting the hardware and instruction presented to the workers' cognitive and physical demands. A modular system architecture is designed accordingly, which allows a flexible component exchange according to the user and the work task. Gamification, the use of game elements in non-gaming contexts, has been further adopted in this work to provide level-based instructions and personalised feedback. The developed framework is validated by applying it to a manual workstation for industrial assembly routines.},
  language  = {en}
}
@inproceedings{MayntzKeimerDahmannetal.2022,
  author    = {Mayntz, Joscha and Keimer, Jona and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham},
  title     = {Electrical Drive and Regeneration in General Aviation Flight with Propellers},
  series = {Deutscher Luft- und Raumfahrtkongress 2020},
  booktitle = {Deutscher Luft- und Raumfahrtkongress 2020},
  publisher = {DGLR},
  address   = {Bonn},
  doi       = {10.25967/530100},
  pages     = {8 Seiten},
  year      = {2022},
  abstract  = {Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft.},
  language  = {en}
}
@inproceedings{SchildtMarzoccaBraunetal.2019,
  author    = {Schildt, Philipp and Marzocca, Pier and Braun, Carsten and Dahmann, Peter and Keimer, Jona},
  title     = {Effects of atmospheric excitation on vibration based condition monitoring methods for hybrid-electric aircraft propulsion systems},
  series = {AIAC 2018: 18th Australian International Aerospace Congress: HUMS - 11th Defence Science and Technology (DST) International Conference on Health and Usage Monitoring (HUMS 2019): ISSFD - 27th International Symposium on Space Flight Dynamics (ISSFD)},
  booktitle = {AIAC 2018: 18th Australian International Aerospace Congress: HUMS - 11th Defence Science and Technology (DST) International Conference on Health and Usage Monitoring (HUMS 2019): ISSFD - 27th International Symposium on Space Flight Dynamics (ISSFD)},
  isbn      = {9781925627213},
  pages     = {923 -- 928},
  year      = {2019},
  language  = {en}
}
@misc{MachadoDahmannKeimeretal.2020,
  author    = {Machado, Patricia Almeida and Dahmann, Peter and Keimer, Jona and Saretzki, Charlotte and St{\"u}bing, Felix and K{\"u}pper, Thomas},
  title     = {Stress profile and individual workload monitoring in general aviation pilots - an experiment's setting},
  series = {23. Annual Meeting of the German Society of Travel Medicine, Coburg, 18.-19.9.2020},
  journal   = {23. Annual Meeting of the German Society of Travel Medicine, Coburg, 18.-19.9.2020},
  doi       = {10.55225/hppa.156},
  year      = {2020},
  language  = {en}
}