@article{DieringerRenzLindeletal.2011,
  author    = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz Dawid and Seifert, Frank and Frauenrath, Tobias and von Knobelsdorf-Brenkenhoff, Florian and Waiczies, Helmar and Hoffmann, Werner and Rieger, Jan and Pfeiffer, Harald and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T},
  series = {Journal of Magnetic Resonance Imaging},
  volume    = {33},
  journal   = {Journal of Magnetic Resonance Imaging},
  number    = {3},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1522-2586},
  doi       = {10.1002/jmri.22451},
  pages     = {736 -- 741},
  year      = {2011},
  abstract  = {Purpose To design and evaluate a four-channel cardiac transceiver coil array for functional cardiac imaging at 7T. Materials and Methods A four-element cardiac transceiver surface coil array was developed with two rectangular loops mounted on an anterior former and two rectangular loops on a posterior former. specific absorption rate (SAR) simulations were performed and a Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-1 calibration method was applied prior to obtain 2D FLASH CINE (mSENSE, R = 2) images from nine healthy volunteers with a spatial resolution of up to 1 × 1 × 2.5 mm3. Results Tuning and matching was found to be better than 10 dB for all subjects. The decoupling (S21) was measured to be >18 dB between neighboring loops, >20 dB for opposite loops, and >30 dB for other loop combinations. SAR values were well within the limits provided by the IEC. Imaging provided clinically acceptable signal homogeneity with an excellent blood-myocardium contrast applying the Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-2 calibration approach. Conclusion A four-channel cardiac transceiver coil array for 7T was built, allowing for cardiac imaging with clinically acceptable signal homogeneity and an excellent blood-myocardium contrast. Minor anatomic structures, such as pericardium, mitral, and tricuspid valves and their apparatus, as well as trabeculae, were accurately delineated.},
  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}
}
@article{BergmannGoettenBraunetal.2022,
  author    = {Bergmann, Ole and G{\"o}tten, Falk and Braun, Carsten and Janser, Frank},
  title     = {Comparison and evaluation of blade element methods against RANS simulations and test data},
  series = {CEAS Aeronautical Journal},
  volume    = {13},
  journal   = {CEAS Aeronautical Journal},
  publisher = {Springer},
  address   = {Wien},
  issn      = {1869-5590 (Online)},
  doi       = {10.1007/s13272-022-00579-1},
  pages     = {535 -- 557},
  year      = {2022},
  abstract  = {This paper compares several blade element theory (BET) method-based propeller simulation tools, including an evaluation against static propeller ground tests and high-fidelity Reynolds-Average Navier Stokes (RANS) simulations. Two proprietary propeller geometries for paraglider applications are analysed in static and flight conditions. The RANS simulations are validated with the static test data and used as a reference for comparing the BET in flight conditions. The comparison includes the analysis of varying 2D aerodynamic airfoil parameters and different induced velocity calculation methods. The evaluation of the BET propeller simulation tools shows the strength of the BET tools compared to RANS simulations. The RANS simulations underpredict static experimental data within 10\% relative error, while appropriate BET tools overpredict the RANS results by 15-20\% relative error. A variation in 2D aerodynamic data depicts the need for highly accurate 2D data for accurate BET results. The nonlinear BET coupled with XFOIL for the 2D aerodynamic data matches best with RANS in static operation and flight conditions. The novel BET tool PropCODE combines both approaches and offers further correction models for highly accurate static and flight condition results.},
  language  = {en}
}
@article{MoehrenBergmannJanseretal.2023,
  author    = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten},
  title     = {On the influence of elasticity on propeller performance: a parametric study},
  series = {CEAS Aeronautical Journal},
  volume    = {14},
  journal   = {CEAS Aeronautical Journal},
  publisher = {Springer Nature},
  address   = {Berlin},
  issn      = {1869-5590 (Online)},
  doi       = {10.1007/s13272-023-00649-y},
  pages     = {311 -- 323},
  year      = {2023},
  abstract  = {The aerodynamic performance of propellers strongly depends on their geometry and, consequently, on aeroelastic deformations. Knowledge of the extent of the impact is crucial for overall aircraft performance. An integrated simulation environment for steady aeroelastic propeller simulations is presented. The simulation environment is applied to determine the impact of elastic deformations on the aerodynamic propeller performance. The aerodynamic module includes a blade element momentum approach to calculate aerodynamic loads. The structural module is based on finite beam elements, according to Timoshenko theory, including moderate deflections. Several fixed-pitch propellers with thin-walled cross sections made of both isotropic and non-isotropic materials are investigated. The essential parameters are varied: diameter, disc loading, sweep, material, rotational, and flight velocity. The relative change of thrust between rigid and elastic blades quantifies the impact of propeller elasticity. Swept propellers of large diameters or low disc loadings can decrease the thrust significantly. High flight velocities and low material stiffness amplify this tendency. Performance calculations without consideration of propeller elasticity can lead to decreased efficiency. To avoid cost- and time-intense redesigns, propeller elasticity should be considered for swept planforms and low disc loadings.},
  language  = {en}
}
@inproceedings{MoehrenBergmannJanseretal.2023,
  author    = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten},
  title     = {On the determination of harmonic propeller loads},
  series = {AIAA SCITECH 2023 Forum},
  booktitle = {AIAA SCITECH 2023 Forum},
  publisher = {AIAA},
  doi       = {10.2514/6.2023-2404},
  pages     = {12 Seiten},
  year      = {2023},
  abstract  = {Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.},
  language  = {en}
}
@article{BergmannMoehrenBraunetal.2023,
  author    = {Bergmann, Ole and M{\"o}hren, Felix and Braun, Carsten and Janser, Frank},
  title     = {On the influence of elasticity on swept propeller noise},
  series = {AIAA SCITECH 2023 Forum},
  journal   = {AIAA SCITECH 2023 Forum},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2023-0210},
  year      = {2023},
  abstract  = {High aerodynamic efficiency requires propellers with high aspect ratios, while propeller sweep potentially reduces noise. Propeller sweep and high aspect ratios increase elasticity and coupling of structural mechanics and aerodynamics, affecting the propeller performance and noise. Therefore, this paper analyzes the influence of elasticity on forward-swept, backward-swept, and unswept propellers in hover conditions. A reduced-order blade element momentum approach is coupled with a one-dimensional Timoshenko beam theory and Farassat's formulation 1A. The results of the aeroelastic simulation are used as input for the aeroacoustic calculation. The analysis shows that elasticity influences noise radiation because thickness and loading noise respond differently to deformations. In the case of the backward-swept propeller, the location of the maximum sound pressure level shifts forward by 0.5 °, while in the case of the forward-swept propeller, it shifts backward by 0.5 °. Therefore, aeroacoustic optimization requires the consideration of propeller deformation.},
  language  = {en}
}
@article{MoehrenBergmannJanseretal.2024,
  author    = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten},
  title     = {Assessment of structural mechanical effects related to torsional deformations of propellers},
  series = {CEAS Aeronautical Journal},
  journal   = {CEAS Aeronautical Journal},
  publisher = {Springer},
  address   = {Wien},
  issn      = {1869-5590 (eISSN)},
  doi       = {10.1007/s13272-024-00737-7},
  pages     = {22 Seiten},
  year      = {2024},
  abstract  = {Lifting propellers are of increasing interest for Advanced Air Mobility. All propellers and rotors are initially twisted beams, showing significant extension-twist coupling and centrifugal twisting. Torsional deformations severely impact aerodynamic performance. This paper presents a novel approach to assess different reasons for torsional deformations. A reduced-order model runs large parameter sweeps with algebraic formulations and numerical solution procedures. Generic beams represent three different propeller types for General Aviation, Commercial Aviation, and Advanced Air Mobility. Simulations include solid and hollow cross-sections made of aluminum, steel, and carbon fiber-reinforced polymer. The investigation shows that centrifugal twisting moments depend on both the elastic and initial twist. The determination of the centrifugal twisting moment solely based on the initial twist suffers from errors exceeding 5\% in some cases. The nonlinear parts of the torsional rigidity do not significantly impact the overall torsional rigidity for the investigated propeller types. The extension-twist coupling related to the initial and elastic twist in combination with tension forces significantly impacts the net cross-sectional torsional loads. While the increase in torsional stiffness due to initial twist contributes to the overall stiffness for General and Commercial Aviation propellers, its contribution to the lift propeller's stiffness is limited. The paper closes with the presentation of approximations for each effect identified as significant. Numerical evaluations are necessary to determine each effect for inhomogeneous cross-sections made of anisotropic material.},
  language  = {en}
}
@misc{DieringerRenzLindeletal.2010,
  author    = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz Dawid and Seifert, Frank and Frauenrath, Tobias and Waiczies, Helmar and von Knobelsdorff-Brenkhoff, Florian and Santoro, Davide and Hoffmann, Werner and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {4CH TX/RX Surface Coil for 7T: Design, Optimization and Application for Cardiac Function Imaging},
  series = {2010 ISMRM-ESMRMB joint annual meeting},
  journal   = {2010 ISMRM-ESMRMB joint annual meeting},
  issn      = {1545-4428},
  year      = {2010},
  abstract  = {Practical impediments of ultra high field cardiovascular MR (CVMR) can be catalogued in exacerbated magnetic field and radio frequency (RF) inhomogeneities, susceptibility and off-resonance effects, conductive and dielectric effects in tissue, and RF power deposition constraints, which all bear the potential to spoil the benefit of CVMR at 7T. Therefore, a four element cardiac transceive surface coil array was developed. Cardiac imaging provided clinically acceptable signal homogeneity with an excellent blood myocardium contrast. Subtle anatomic structures, such as pericardium, mitral and tricuspid valves and their apparatus, papillary muscles, and trabecles were accurately delineated.},
  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{LindelGreiserWaxmanetal.2012,
  author    = {Lindel, Tomasz Dawid and Greiser, Andreas and Waxman, Patrick and Dietterle, Martin and Seifert, Frank and Fontius, Ulrich and Renz, Wolfgang and Dieringer, Matthias A. and Frauenrath, Tobias and Schulz-Menger, Jeanette and Niendorf, Thoralf and Ittermann, Bernd},
  title     = {Cardiac CINE MRI at 7 T using a transmit array},
  series = {2012 ISMRM Annual Meeting Proceedings},
  journal   = {2012 ISMRM Annual Meeting Proceedings},
  issn      = {1545-4428},
  year      = {2012},
  abstract  = {With its need for high SNR and short acquisition times, Cardiac MRI (CMR) is an intriguing target application for ultrahigh field MRI. Due to the sheer size of the upper torso, however, the known RF issues of 7T MRI are also most prominent in CMR. Recent years brought substantial progress but the full potential of the ultrahigh field for CMR is yet to be exploited. Parallel transmission (pTx) is a promising approach in this context and several groups have already reported B1 shimming for 7T CMR. In such a static pTx application amplitudes and phases of all Tx channels are adjusted individually but otherwise imaging techniques established in current clinical practice 1.5 T and 3 T are applied. More advanced forms of pTx as spatially selective excitation (SSE) using Transmit SENSE promise additional benefits like faster imaging with reduced fields of view or improved SAR control. SSE requires the full dynamic capabilities of pTx, however, and for the majority of today's implemented pTx hardware the internal synchronization of the Tx array does not easily permit external triggering as needed for CMR. Here we report a software solution to this problem and demonstrate the feasibility of CINE CMR at 7 T using a Tx array.},
  language  = {en}
}
@article{BerretzSkorupaSanderetal.2011,
  author    = {Berretz, Frank and Skorupa, Sascha and Sander, Volker and Belloum, Adam and Bubak, Marian},
  title     = {Actor-Driven Workflow Execution in Distributed Environments},
  series = {Euro-Par 2010 Parallel Processing Workshops : HeteroPAR, HPCC, HiBB, CoreGrid, UCHPC, HPCF, PROPER, CCPI, VHPC ; Ischia, Italy, August 31 - September 3, 2010 ; revised selected papers / Mario R. Guarracino ... (eds.)},
  journal   = {Euro-Par 2010 Parallel Processing Workshops : HeteroPAR, HPCC, HiBB, CoreGrid, UCHPC, HPCF, PROPER, CCPI, VHPC ; Ischia, Italy, August 31 - September 3, 2010 ; revised selected papers / Mario R. Guarracino ... (eds.)},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-642-21877-4},
  pages     = {287 -- 294},
  year      = {2011},
  language  = {en}
}
@inproceedings{MichauxBrunnWillertetal.2024,
  author    = {Michaux, Frank and Brunn, Andr{\´e} and Willert, Christian and Kallweit, Stephan},
  title     = {Automatic setup and calibration of a Robotic-PIV system using fiducial markers},
  series = {21st International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics},
  booktitle = {21st International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics},
  doi       = {10.55037/lxlaser.21st.163},
  pages     = {12 Seiten},
  year      = {2024},
  abstract  = {The use of industrial robots allows the precise manipulation of all components necessary for setting up a large-scale particle image velocimetry (PIV) system. The known internal calibration matrix of the cameras in combination with the actual pose of the industrial robots and the calculated transform from the fiducial markers to camera coordinates allow the precise positioning of the individual PIV components according to the measurement demands. In addition, the complete calibration procedure for generating the external camera matrix and the mapping functions for e.g. dewarping the stereo images can be automatically determined without further user interaction and thus the degree of automation can be extended to nearly 100\%. This increased degree of automation expands the applications range of PIV systems, in particular for measurement tasks with severe time constraints.},
  language  = {en}
}
@article{SlabuRoethEngelmannetal.2019,
  author    = {Slabu, Ioana and Roeth, Anjali A. and Engelmann, Ulrich M. and Wiekhorst, Frank and Buhl, Eva Miriam and Neumann, Ulf P. and Schmitz-Rode, Thomas},
  title     = {Modeling of magnetoliposome uptake in human pancreatic tumor cells in vitro},
  series = {Nanotechnology},
  volume    = {30},
  journal   = {Nanotechnology},
  number    = {18},
  issn      = {1361-6528},
  doi       = {10.1088/1361-6528/ab033e},
  pages     = {184004},
  year      = {2019},
  language  = {en}
}
@article{TeumerCapitainRossJonesetal.2018,
  author    = {Teumer, Tobias and Capitain, Charlotte and Ross-Jones, Jesse and Tippk{\"o}tter, Nils and R{\"a}dle, Matthias and Methner, Frank-J{\"u}rgen},
  title     = {In-line Haze Monitoring Using a Spectrally Resolved Back Scattering Sensor},
  series = {BrewingScience},
  volume    = {71},
  journal   = {BrewingScience},
  number    = {5/6},
  publisher = {Fachverlag Hans Carl},
  address   = {N{\"u}rnberg},
  issn      = {1613-2041},
  pages     = {49 -- 55},
  year      = {2018},
  abstract  = {In the present work an optical sensor in combination with a spectrally resolved detection device for in-line particle-size-monitoring for quality control in beer production is presented. The principle relies on the size and wavelength dependent backscatter of growing particles in fluids. Measured interference structures of backscattered light are compared with calculated theoretical values, based on Mie-Theory, and fitted with a linear least square method to obtain particle size distributions. For this purpose, a broadband light source in combination with a process-CCD-spectrometer (charge ? coupled device spectrometer) and process adapted fiber optics are used. The goal is the development of an easy and flexible measurement device for in-line-monitoring of particle size. The presented device can be directly installed in product fill tubes or vessels, follows CIP- (cleaning in place) and removes the need of sample taking. A proof of concept and preliminary results, measuring protein precipitation, are presented.},
  language  = {en}
}
@misc{RossJonesTeumerCapitainetal.2018,
  author    = {Ross-Jones, Jesse and Teumer, Tobias and Capitain, Charlotte and Tippk{\"o}tter, Nils and Krause, Mathias J. and Methner, Frank-J{\"u}rgen and R{\"a}dle, Matthias},
  title     = {Analytical methods for in-line characterization of beer haze},
  series = {Trends in Brewing},
  journal   = {Trends in Brewing},
  year      = {2018},
  abstract  = {In most beers, producers strive to minimize haze to maximize visual appeal. To detect the formation of particulates, a measurement system for sub-micron particles is required. Beer haze is naturally occurring, composed of protein or polyphenol particles; in their early stage of growth their size is smaller than 2 µm. Microscopy analysis is time and resource intensive; alternatively, backscattering is an inexpensive option for detecting particle sizes of interest.},
  language  = {en}
}