@article{AbbasHedwigBalcetal.2023,
  author    = {Abbas, Karim and Hedwig, Lukas and Balc, Nicolae and Bremen, Sebastian},
  title     = {Advanced FFF of PEEK: Infill strategies and material characteristics for rapid tooling},
  series = {Polymers},
  volume    = {2023},
  journal   = {Polymers},
  number    = {15},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/polym15214293},
  pages     = {Artikel 4293},
  year      = {2023},
  abstract  = {Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK's economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100\% solid and subjected to thermal post-treatment. This corresponds to a 20\% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15\% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70\% in tool production.},
  language  = {en}
}
@article{FayyaziSardarThomasetal.2023,
  author    = {Fayyazi, Mojgan and Sardar, Paramjotsingh and Thomas, Sumit Infent and Daghigh, Roonak and Jamali, Ali and Esch, Thomas and Kemper, Hans and Langari, Reza and Khayyam, Hamid},
  title     = {Artificial intelligence/machine learning in energy management systems, control, and optimization of hydrogen fuel cell vehicles},
  volume    = {15},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/su15065249},
  pages     = {38},
  year      = {2023},
  abstract  = {Environmental emissions, global warming, and energy-related concerns have accelerated the advancements in conventional vehicles that primarily use internal combustion engines. Among the existing technologies, hydrogen fuel cell electric vehicles and fuel cell hybrid electric vehicles may have minimal contributions to greenhouse gas emissions and thus are the prime choices for environmental concerns. However, energy management in fuel cell electric vehicles and fuel cell hybrid electric vehicles is a major challenge. Appropriate control strategies should be used for effective energy management in these vehicles. On the other hand, there has been significant progress in artificial intelligence, machine learning, and designing data-driven intelligent controllers. These techniques have found much attention within the community, and state-of-the-art energy management technologies have been developed based on them. This manuscript reviews the application of machine learning and intelligent controllers for prediction, control, energy management, and vehicle to everything (V2X) in hydrogen fuel cell vehicles. The effectiveness of data-driven control and optimization systems are investigated to evolve, classify, and compare, and future trends and directions for sustainability are discussed.},
  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}
}
@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{WendlandtKochBritzetal.2023,
  author    = {Wendlandt, Tim and Koch, Claudia and Britz, Beate and Liedek, Anke and Schmidt, Nora and Werner, Stefan and Gleba, Yuri and Vahidpour, Farnoosh and Welden, Melanie and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Facile Purification and Use of Tobamoviral Nanocarriers for Antibody-Mediated Display of a Two-Enzyme System},
  series = {Viruses},
  volume    = {9},
  journal   = {Viruses},
  number    = {15},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1999-4915},
  doi       = {doi.org/10.3390/v15091951},
  pages     = {Artikel 1951},
  year      = {2023},
  abstract  = {Immunosorbent turnip vein clearing virus (TVCV) particles displaying the IgG-binding domains D and E of Staphylococcus aureus protein A (PA) on every coat protein (CP) subunit (TVCVPA) were purified from plants via optimized and new protocols. The latter used polyethylene glycol (PEG) raw precipitates, from which virions were selectively re-solubilized in reverse PEG concentration gradients. This procedure improved the integrity of both TVCVPA and the wild-type subgroup 3 tobamovirus. TVCVPA could be loaded with more than 500 IgGs per virion, which mediated the immunocapture of fluorescent dyes, GFP, and active enzymes. Bi-enzyme ensembles of cooperating glucose oxidase and horseradish peroxidase were tethered together on the TVCVPA carriers via a single antibody type, with one enzyme conjugated chemically to its Fc region, and the other one bound as a target, yielding synthetic multi-enzyme complexes. In microtiter plates, the TVCVPA-displayed sugar-sensing system possessed a considerably increased reusability upon repeated testing, compared to the IgG-bound enzyme pair in the absence of the virus. A high coverage of the viral adapters was also achieved on Ta2O5 sensor chip surfaces coated with a polyelectrolyte interlayer, as a prerequisite for durable TVCVPA-assisted electrochemical biosensing via modularly IgG-assembled sensor enzymes.},
  language  = {en}
}
@article{StiemerThomaBraun2023,
  author    = {Stiemer, Luc Nicolas and Thoma, Andreas and Braun, Carsten},
  title     = {MBT3D: Deep learning based multi-object tracker for bumblebee 3D flight path estimation},
  series = {PLoS ONE},
  volume    = {18},
  journal   = {PLoS ONE},
  number    = {9},
  publisher = {PLOS},
  address   = {San Fancisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0291415},
  pages     = {e0291415},
  year      = {2023},
  abstract  = {This work presents the Multi-Bees-Tracker (MBT3D) algorithm, a Python framework implementing a deep association tracker for Tracking-By-Detection, to address the challenging task of tracking flight paths of bumblebees in a social group. While tracking algorithms for bumblebees exist, they often come with intensive restrictions, such as the need for sufficient lighting, high contrast between the animal and background, absence of occlusion, significant user input, etc. Tracking flight paths of bumblebees in a social group is challenging. They suddenly adjust movements and change their appearance during different wing beat states while exhibiting significant similarities in their individual appearance. The MBT3D tracker, developed in this research, is an adaptation of an existing ant tracking algorithm for bumblebee tracking. It incorporates an offline trained appearance descriptor along with a Kalman Filter for appearance and motion matching. Different detector architectures for upstream detections (You Only Look Once (YOLOv5), Faster Region Proposal Convolutional Neural Network (Faster R-CNN), and RetinaNet) are investigated in a comparative study to optimize performance. The detection models were trained on a dataset containing 11359 labeled bumblebee images. YOLOv5 reaches an Average Precision of AP = 53, 8\%, Faster R-CNN achieves AP = 45, 3\% and RetinaNet AP = 38, 4\% on the bumblebee validation dataset, which consists of 1323 labeled bumblebee images. The tracker's appearance model is trained on 144 samples. The tracker (with Faster R-CNN detections) reaches a Multiple Object Tracking Accuracy MOTA = 93, 5\% and a Multiple Object Tracking Precision MOTP = 75, 6\% on a validation dataset containing 2000 images, competing with state-of-the-art computer vision methods. The framework allows reliable tracking of different bumblebees in the same video stream with rarely occurring identity switches (IDS). MBT3D has much lower IDS than other commonly used algorithms, with one of the lowest false positive rates, competing with state-of-the-art animal tracking algorithms. The developed framework reconstructs the 3-dimensional (3D) flight paths of the bumblebees by triangulation. It also handles and compares two alternative stereo camera pairs if desired.},
  language  = {en}
}
@article{NiedermeierPennerUsherovichetal.2023,
  author    = {Niedermeier, Jana and Penner, Crystal and Usherovich, Samuel and B{\´e}langer-Champagne, Camille and Paulßen, Elisabeth and Hoehr, Cornelia},
  title     = {Optical Fibers as Dosimeter Detectors for Mixed Proton/Neutron Fields - A Biological Dosimeter},
  series = {electronics},
  volume    = {12},
  journal   = {electronics},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-9292},
  doi       = {10.3390/electronics12020324},
  pages     = {11 Seiten},
  year      = {2023},
  abstract  = {In recent years, proton therapy has gained importance as a cancer treatment modality due to its conformality with the tumor and the sparing of healthy tissue. However, in the interaction of the protons with the beam line elements and patient tissues, potentially harmful secondary neutrons are always generated. To ensure that this neutron dose is as low as possible, treatment plans could be created to also account for and minimize the neutron dose. To monitor such a treatment plan, a compact, easy to use, and inexpensive dosimeter must be developed that not only measures the physical dose, but which can also distinguish between proton and neutron contributions. To that end, plastic optical fibers with scintillation materials (Gd₂O₂S:Tb, Gd₂O₂S:Eu, and YVO₄:Eu) were irradiated with protons and neutrons. It was confirmed that sensors with different scintillation materials have different sensitivities to protons and neutrons. A combination of these three scintillators can be used to build a detector array to create a biological dosimeter.},
  language  = {en}
}
@article{BertzMolinnusSchoeningetal.2023,
  author    = {Bertz, Morten and Molinnus, Denise and Sch{\"o}ning, Michael Josef and Homma, Takayuki},
  title     = {Real-time monitoring of H₂O₂ sterilization on individual bacillus atrophaeus spores by optical sensing with trapping Raman spectroscopy},
  series = {Chemosensors},
  volume    = {8},
  journal   = {Chemosensors},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9040},
  doi       = {10.3390/chemosensors11080445},
  pages     = {Artikel 445},
  year      = {2023},
  abstract  = {Hydrogen peroxide (H₂O₂), a strong oxidizer, is a commonly used sterilization agent employed during aseptic food processing and medical applications. To assess the sterilization efficiency with H₂O₂, bacterial spores are common microbial systems due to their remarkable robustness against a wide variety of decontamination strategies. Despite their widespread use, there is, however, only little information about the detailed time-resolved mechanism underlying the oxidative spore death by H₂O₂. In this work, we investigate chemical and morphological changes of individual Bacillus atrophaeus spores undergoing oxidative damage using optical sensing with trapping Raman microscopy in real-time. The time-resolved experiments reveal that spore death involves two distinct phases: (i) an initial phase dominated by the fast release of dipicolinic acid (DPA), a major spore biomarker, which indicates the rupture of the spore's core; and (ii) the oxidation of the remaining spore material resulting in the subsequent fragmentation of the spores' coat. Simultaneous observation of the spore morphology by optical microscopy corroborates these mechanisms. The dependence of the onset of DPA release and the time constant of spore fragmentation on H₂O₂ shows that the formation of reactive oxygen species from H₂O₂ is the rate-limiting factor of oxidative spore death.},
  language  = {en}
}
@article{BaaderBoxbergChenetal.2023,
  author    = {Baader, Fabian and Boxberg, Marc S. and Chen, Qian and F{\"o}rstner, Roger and Kowalski, Julia and Dachwald, Bernd},
  title     = {Field-test performance of an ice-melting probe in a terrestrial analogue environment},
  series = {Icarus},
  journal   = {Icarus},
  number    = {409},
  publisher = {Elsevier},
  address   = {Amsterdam},
  doi       = {10.1016/j.icarus.2023.115852},
  pages     = {Artikel 115852},
  year      = {2023},
  abstract  = {Melting probes are a proven tool for the exploration of thick ice layers and clean sampling of subglacial water on Earth. Their compact size and ease of operation also make them a key technology for the future exploration of icy moons in our Solar System, most prominently Europa and Enceladus. For both mission planning and hardware engineering, metrics such as efficiency and expected performance in terms of achievable speed, power requirements, and necessary heating power have to be known. Theoretical studies aim at describing thermal losses on the one hand, while laboratory experiments and field tests allow an empirical investigation of the true performance on the other hand. To investigate the practical value of a performance model for the operational performance in extraterrestrial environments, we first contrast measured data from terrestrial field tests on temperate and polythermal glaciers with results from basic heat loss models and a melt trajectory model. For this purpose, we propose conventions for the determination of two different efficiencies that can be applied to both measured data and models. One definition of efficiency is related to the melting head only, while the other definition considers the melting probe as a whole. We also present methods to combine several sources of heat loss for probes with a circular cross-section, and to translate the geometry of probes with a non-circular cross-section to analyse them in the same way. The models were selected in a way that minimizes the need to make assumptions about unknown parameters of the probe or the ice environment. The results indicate that currently used models do not yet reliably reproduce the performance of a probe under realistic conditions. Melting velocities and efficiencies are constantly overestimated by 15 to 50 \% in the models, but qualitatively agree with the field test data. Hence, losses are observed, that are not yet covered and quantified by the available loss models. We find that the deviation increases with decreasing ice temperature. We suspect that this mismatch is mainly due to the too restrictive idealization of the probe model and the fact that the probe was not operated in an efficiency-optimized manner during the field tests. With respect to space mission engineering, we find that performance and efficiency models must be used with caution in unknown ice environments, as various ice parameters have a significant effect on the melting process. Some of these are difficult to estimate from afar.},
  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{MikuckiSchulerDigeletal.2023,
  author    = {Mikucki, Jill Ann and Schuler, C. G. and Digel, Ilya and Kowalski, Julia and Tuttle, M. J. and Chua, Michelle and Davis, R. and Purcell, Alicia and Ghosh, D. and Francke, G. and Feldmann, M. and Espe, C. and Heinen, Dirk and Dachwald, Bernd and Clemens, Joachim and Lyons, W. B. and Tulaczyk, S.},
  title     = {Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem},
  series = {Astrobiology},
  volume    = {23},
  journal   = {Astrobiology},
  number    = {11},
  publisher = {Liebert},
  address   = {New York, NY},
  issn      = {1557-8070 (online)},
  doi       = {10.1089/ast.2021.0102},
  pages     = {1165 -- 1178},
  year      = {2023},
  abstract  = {Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063\% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.},
  language  = {en}
}
@article{BoehnertBlaschkeBiewendt2023,
  author    = {B{\"o}hnert, Arno and Blaschke, Florian and Biewendt, Marcel},
  title     = {Impact of sustainability on the strategic direction of luxury companies},
  series = {European Journal of Marketing and Economics},
  volume    = {6},
  journal   = {European Journal of Marketing and Economics},
  number    = {1},
  publisher = {Revistia},
  address   = {London},
  issn      = {2601-8659},
  pages     = {70 -- 85},
  year      = {2023},
  abstract  = {Today's society is undergoing a paradigm shift driven by the megatrend of sustainability. This undeniably affects all areas of Western life. This paper aims to find out how the luxury industry is dealing with this change and what adjustments are made by the companies. For this purpose, interviews were conducted with managers from the luxury industry, in which they were asked about specific measures taken by their companies as well as trends in the industry. In a subsequent evaluation, the trends in the luxury industry were summarized for the areas of ecological, social, and economic sustainability. It was found that the area of environmental sustainability is significantly more focused than the other sub-areas. Furthermore, the need for a customer survey to validate the industry-based measures was identified.},
  language  = {en}
}
@article{BertzSchoeningMolinnusetal.2024,
  author    = {Bertz, Morten and Sch{\"o}ning, Michael Josef and Molinnus, Denise and Homma, Takayuki},
  title     = {Influence of temperature, light, and H₂O₂ concentration on microbial spore inactivation: in-situ Raman spectroscopy combined with optical trapping},
  series = {Physica status solidi (a) applications and materials science},
  journal   = {Physica status solidi (a) applications and materials science},
  number    = {Early View},
  publisher = {Wiley-VCH},
  address   = {Berlin},
  issn      = {1862-6319 (Online)},
  doi       = {10.1002/pssa.202300866},
  pages     = {8 Seiten},
  year      = {2024},
  abstract  = {To gain insight on chemical sterilization processes, the influence of temperature (up to 70 °C), intense green light, and hydrogen peroxide (H₂O₂) concentration (up to 30\% in aqueous solution) on microbial spore inactivation is evaluated by in-situ Raman spectroscopy with an optical trap. Bacillus atrophaeus is utilized as a model organism. Individual spores are isolated and their chemical makeup is monitored under dynamically changing conditions (temperature, light, and H₂O₂ concentration) to mimic industrially relevant process parameters for sterilization in the field of aseptic food processing. While isolated spores in water are highly stable, even at elevated temperatures of 70 °C, exposure to H₂O₂ leads to a loss of spore integrity characterized by the release of the key spore biomarker dipicolinic acid (DPA) in a concentration-dependent manner, which indicates damage to the inner membrane of the spore. Intensive light or heat, both of which accelerate the decomposition of H₂O₂ into reactive oxygen species (ROS), drastically shorten the spore lifetime, suggesting the formation of ROS as a rate-limiting step during sterilization. It is concluded that Raman spectroscopy can deliver mechanistic insight into the mode of action of H₂O₂-based sterilization and reveal the individual contributions of different sterilization methods acting in tandem.},
  language  = {en}
}
@article{SchoenrockMuckeltHastermannetal.2024,
  author    = {Schoenrock, Britt and Muckelt, Paul E. and Hastermann, Maria and Albracht, Kirsten and MacGregor, Robert and Martin, David and Gunga, Hans-Christian and Salanova, Michele and Stokes, Maria J. and Warner, Martin B. and Blottner, Dieter},
  title     = {Muscle stiffness indicating mission crew health in space},
  series = {Scientific Reports},
  volume    = {14},
  journal   = {Scientific Reports},
  number    = {Article number: 4196},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-024-54759-6},
  pages     = {13 Seiten},
  year      = {2024},
  abstract  = {Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes.},
  language  = {en}
}
@article{KochBoehnischVerdoncketal.2024,
  author    = {Koch, Christopher and B{\"o}hnisch, Nils and Verdonck, Hendrik and Hach, Oliver and Braun, Carsten},
  title     = {Comparison of unsteady low- and mid-fidelity propeller aerodynamic methods for whirl flutter applications},
  series = {Applied Sciences},
  volume    = {14},
  journal   = {Applied Sciences},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2076-3417},
  doi       = {10.3390/app14020850},
  pages     = {1 -- 28},
  year      = {2024},
  abstract  = {Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction.},
  language  = {en}
}
@article{HoffstadtNikolauszKrafftetal.2024,
  author    = {Hoffstadt, Kevin and Nikolausz, Marcell and Krafft, Simone and Bonatelli, Maria and Kumar, Vivekanantha and Harms, Hauke and Kuperjans, Isabel},
  title     = {Optimization of the ex situ biomethanation of hydrogen and carbon dioxide in a novel meandering plug flow reactor: start-up phase and flexible operation},
  series = {Bioengineering},
  volume    = {11},
  journal   = {Bioengineering},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2306-5354},
  doi       = {10.3390/bioengineering11020165},
  pages     = {18 Seiten},
  year      = {2024},
  language  = {en}
}
@article{BoehnischBraunMuscarelloetal.2024,
  author    = {B{\"o}hnisch, Nils and Braun, Carsten and Muscarello, Vincenzo and Marzocca, Pier},
  title     = {About the wing and whirl flutter of a slender wing-propeller system},
  series = {Journal of Aircraft},
  journal   = {Journal of Aircraft},
  publisher = {AIAA},
  address   = {Reston, Va.},
  issn      = {1533-3868},
  doi       = {10.2514/1.C037542},
  pages     = {1 -- 14},
  year      = {2024},
  abstract  = {Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan (distributed electric propulsion), leading to highly flexible dynamic systems that can exhibit aeroelastic instabilities. This paper introduces a validated methodology to investigate the aeroelastic instabilities of wing-propeller systems and to understand the dynamic mechanism leading to wing and whirl flutter and transition from one to the other. Factors such as nacelle positions along the wing span and chord and its propulsion system mounting stiffness are considered. Additionally, preliminary design guidelines are proposed for flutter-free wing-propeller systems applicable to novel aircraft designs. The study demonstrates how the critical speed of the wing-propeller systems is influenced by the mounting stiffness and propeller position. Weak mounting stiffnesses result in whirl flutter, while hard mounting stiffnesses lead to wing flutter. For the latter, the position of the propeller along the wing span may change the wing mode shapes and thus the flutter mechanism. Propeller positions closer to the wing tip enhance stability, but pusher configurations are more critical due to the mass distribution behind the elastic axis.},
  language  = {en}
}
@article{ChwallekNawrathKrastinaetal.2024,
  author    = {Chwallek, Constanze and Nawrath, Lara and Krastina, Anzelika and Bruksle, Ieva},
  title     = {Supportive research on sustainable entrepreneurship and business practices},
  series = {SECA Sustainable Entrepreneurship for Climate Action},
  journal   = {SECA Sustainable Entrepreneurship for Climate Action},
  number    = {3},
  publisher = {Lapland University of Applied Sciences Ltd},
  address   = {Rovaniemi},
  isbn      = {978-952-316-514-4 (pdf)},
  issn      = {2954-1654 (on-line publication)},
  pages     = {67 Seiten},
  year      = {2024},
  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}
}
@article{PogorelovaRogachevAkimbekovetal.2024,
  author    = {Pogorelova, Natalia and Rogachev, Evgeniy and Akimbekov, Nuraly S. and Digel, Ilya},
  title     = {Effect of dehydration method on the micro- and nanomorphological properties of bacterial cellulose produced by Medusomyces gisevii on different substrates},
  series = {Journal of materials science},
  volume    = {2024},
  journal   = {Journal of materials science},
  publisher = {Springer Science + Business Media},
  address   = {Dordrecht},
  issn      = {1573-4803 (Online)},
  doi       = {10.1007/s10853-024-09596-3},
  pages     = {13 Seiten},
  year      = {2024},
  abstract  = {Many important properties of bacterial cellulose (BC), such as moisture absorption capacity, elasticity and tensile strength, largely depend on its structure. This paper presents a study on the effect of the drying method on BC films produced by Medusomyces gisevii using two different procedures: room temperature drying (RT, (24 ± 2 °C, humidity 65 ± 1\%, dried until a constant weight was reached) and freeze-drying (FD, treated at - 75 °C for 48 h). BC was synthesized using one of two different carbon sources—either glucose or sucrose. Structural differences in the obtained BC films were evaluated using atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction. Macroscopically, the RT samples appeared semi-transparent and smooth, whereas the FD group exhibited an opaque white color and sponge-like structure. SEM examination showed denser packing of fibrils in FD samples while RT-samples displayed smaller average fiber diameter, lower surface roughness and less porosity. AFM confirmed the SEM observations and showed that the FD material exhibited a more branched structure and a higher surface roughness. The samples cultivated in a glucose-containing nutrient medium, generally displayed a straight and ordered shape of fibrils compared to the sucrose-derived BC, characterized by a rougher and wavier structure. The BC films dried under different conditions showed distinctly different crystallinity degrees, whereas the carbon source in the culture medium was found to have a relatively small effect on the BC crystallinity.},
  language  = {en}
}