@incollection{MannWenzlerDoehringetal.2022, author = {Mann, Michael and Wenzler, Sebastian and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Pribulla, Theodor and Sivanič, Peter and Komž{\´i}k, Richard}, title = {Stromversorgung als Umweltfaktor: Analyse der elektrischen Netzqualit{\"a}t in astronomischen Observatorien}, series = {Umwelteinfl{\"u}sse erfassen, simulieren, bewerten}, volume = {2022}, booktitle = {Umwelteinfl{\"u}sse erfassen, simulieren, bewerten}, editor = {Karl Friedrich, Zieghahn}, publisher = {Gesellschaft f{\"u}r Umweltsimulation e.V.}, isbn = {978-3-9818507-7-2}, pages = {193 -- 207}, year = {2022}, subject = {Sternwarte}, language = {de} } @misc{StanikDoehringPregleretal.2024, author = {Stanik, Eva and D{\"o}hring, Thorsten and Pregler, Jan and Stollenwerk, Manfred and Hildenbrand, Georg}, title = {Spectral measurements and life science experiments using extreme radiation exposures at high altitude}, organization = {Technische Hochschule Aschaffenburg}, pages = {1}, year = {2024}, abstract = {The ASTRABAX project ("Aschaffenburg Stratospheric Balloon Experiment"), being funded for the years 2024 to 2026, is designed as a multimodal platform for the investigation of radiation exposures at high altitude. Miniature UV-VIS spectrometers observe the UV-C spectral region. The platform also contains a radiation dosimetry, a power source for on-board electronics, and common shielding setups for multiple spectral combinations. The effects of combinations of high- and low-energy rays on human cells haven´t been sufficiently investigated and described so far. Investigations under such conditions are realistic and crucial for high altitude flights in the atmosphere, for space flights as well as for comparable exposures on other objects of the solar system, and even for exoplanet habitats to some extent.}, subject = {Stahlenbelastung}, language = {en} } @inproceedings{MannDoehringStollenwerketal.2024, author = {Mann, Michael and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Priebsch, Alessandro and Pribulla, Theodor and Komž{\´i}k, Richard M. and Sivanic, Peter}, title = {Advanced power quality measurement techniques at the electric power grid of astronomical observatories}, series = {Observatory Operations: Strategies, Processes, and Systems X, Conference of SPIE 13098, 17 - 20 June 2024}, booktitle = {Observatory Operations: Strategies, Processes, and Systems X, Conference of SPIE 13098, 17 - 20 June 2024}, editor = {Storrie-Lombardi, Lisa J. and Benn, Chris R. and Chrysostomou, Antonio}, publisher = {SPIE}, doi = {10.1117/12.3016562}, year = {2024}, subject = {Sternwarte}, language = {en} } @inproceedings{MannDoehringStollenwerketal.2022, author = {Mann, Michael and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Wenzler, Sebastian and Pribulla, Theodor and Komž{\´i}k, Richard M. and Sivanic, Peter}, title = {On the importance of the electrical grid power quality for astronomical observatories}, series = {Proceedings of SPIE: Observatory Operations: Strategies, Processes, and Systems IX}, booktitle = {Proceedings of SPIE: Observatory Operations: Strategies, Processes, and Systems IX}, editor = {Benn, Chris R. and Seaman, Robert L. and Adler, David S.}, publisher = {SPIE}, doi = {http://dx.doi.org/10.1117/12.2627227}, year = {2022}, subject = {Elektrizit{\"a}tsversorgung}, language = {en} } @inproceedings{DoehringStanikPregleretal.2024, author = {D{\"o}hring, Thorsten and Stanik, Eva and Pregler, Jan and Stollenwerk, Manfred and Hildenbrand, Georg}, title = {Forschung zu Strahlensch{\"a}den mit dem Stratosph{\"a}renballon-Experiment ASTRABAX}, series = {DGaO-Proceedings}, volume = {2024}, booktitle = {DGaO-Proceedings}, number = {125}, pages = {1 -- 2}, year = {2024}, abstract = {Das Stratosph{\"a}renballon-Experiment ASTRABAX ist als multimodale Plattform der Material- und Biowissenschaften f{\"u}r Untersuchungen bei extremen Strahlenbelastungen konzipiert, mit Fokus auf dem UV-C-Spektralbereich und der kosmischen H{\"o}henstrahlung. Auswirkungen von Kombinationen aus hoch- und niederenergetischer Strahlung sind relevant, jedoch nicht ausreichend erforscht.}, subject = {Stratosph{\"a}ren-Ballon}, language = {de} } @article{AmorimSperaNicoaraetal.2024, author = {Amorim, Isilda and Spera, Natalia C.M. and Nicoara, Nicoleta and Ramasamy, Devaraj and Alves, Diana F. and Stollenwerk, Manfred and Stadtm{\"u}ller, Johannes and D{\"o}hring, Thorsten and Sadewasser, Sascha and Kolen'ko, Yury V. and Sousa, Juliana P.S.}, title = {Overall alkaline water electrolysis over active, stable, low loading iridium catalysts sputtered on nickel foam}, series = {International Journal of Hydrogen Energy}, volume = {92}, journal = {International Journal of Hydrogen Energy}, publisher = {Elsevier BV}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2024.10.306}, pages = {852 -- 864}, year = {2024}, subject = {Iridium}, language = {en} } @incollection{WisselFreudenmannPerezetal.2025, author = {Wissel, Julian and Freudenmann, Dominic and Perez, Nicolas and D{\"o}hring, Thorsten and Stadtm{\"u}ller, Johannes and Stollenwerk, Manfred}, title = {Various highly effective sputtered layer structures as catalysts for H2O2 decomposition for use in satellite engines}, series = {MaterialsWeek 2025 - Book of Abstracts}, booktitle = {MaterialsWeek 2025 - Book of Abstracts}, publisher = {Deutsche Gesellschaft f{\"u}r Materialkunde e.V. (DGM)}, address = {Sankt Augustin}, isbn = {978-3-88355-446-4}, pages = {53 -- 53}, year = {2025}, abstract = {Catalysts are frequently employed in both research and industrial applications to facilitate or accelerate chemical reactions. One such application is in monopropellant thrusters for space propulsion systems, where hydrogen peroxide (H2O2) is used as a liquid propellant. The decomposition of liquid hydrogen peroxide into water and oxygen gas, which ultimately generates thrust, can be achieved using noble metal catalysts from the platinoid group, such as platinum and iridium. This promotes the use of more environmentally friendly and less toxic propellants, such as H2O2, instead of hydrazine and nitrogen tetroxide (NTO). The optimization of coating structures with these catalytic materials is essential for future space applications, as it aims to extend the lifespan of catalyst materials and results in a better utilization of H2O2 in satellite engines. Therefore, different layer structures were deposited onto Duranit D99 pellets using a controlled magnetron sputtering process. Previous studies have shown that the used sputtering pressure has a strong influence on the structure of the deposited coatings [2][3]. Certain parameter combinations produce catalytic layers with rough textures and a highly porous microstructure, see figure 1 [1]. To improve the thermal and mechanical stability of the sputtered layers, thin adhesive layers of Titanium and Zirconium were applied beneath the catalytic layer. The pellets were then heated in an oven at 640°C for one minute to simulate the thermal effects experienced in a satellite engine during ignition. Following this, the catalytic performance of the pellets was tested in laboratory experiments using 30\% H2O2. Pellets with sputtered platinum as the catalytic coating delivered the best results. These coatings will be further evaluated in an engine test conducted at the German Aerospace Centre (DLR). Hydrogen peroxide is also expected to play a crucial role in future lunar and Martian colonization efforts. In this context, catalytic coatings would be used to decompose H2O2 to supply astronauts with water and oxygen, rather than to generate thrust in satellite engines.}, subject = {Satellitentechnik}, language = {en} } @misc{LicciardelloDoehringStollenwerketal.2021, author = {Licciardello, Nadia and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Kolen'ko, Yury V. and Petrovykh, Dmitri Y.}, title = {Innovative nanocomposite coatings for radiation shielding on satellites}, series = {EuroNanoForum}, volume = {2021}, journal = {EuroNanoForum}, organization = {International Iberian Nanotechnology Laboratory}, pages = {1}, year = {2021}, abstract = {The current trend in development of low-cost satellites is based on small dimensions combined with advanced electronics. Traditionally, radiation-sensitive electronics on satellites are protected by tungsten or lead foils, which are high-density materials and contribute significantly to the overall mass of the satellite. Here, we design and investigate temperature-gradient-resistant lightweight silane-based composites containing micro- or nano-particles of W or WO3, taking inspiration from similar approaches in the medical field. While the polymeric matrix provides flexibility under thermal gradients (such as those occurring in satellites during their orbits) and low density, the particles enable shielding from soft X-rays and other radiation. For reference, thin tungsten films were deposited by magnetron sputtering. The properties of the two kinds of coatings were compared and the X-ray protective properties were investigated using both a custom-designed measurement setup and conventional X-ray absorption. The best performing radiation-protective coatings will be launched in a payload experiment on the INFANTE satellite.}, subject = {Satellitentechnik}, language = {en} } @inproceedings{RivoltaBassoCivitanietal.2022, author = {Rivolta, Giacomo and Basso, Stefano and Civitani, Marta Maria and Cotroneo, Vincenzo and D{\"o}hring, Thorsten and Michler, Willy-Leopold and Pareschi, Giovanni and Spiga, Daniele and Stollenwerk, Manfred}, title = {Upgrade of a laboratory X-ray diffractometer to extend its operating range towards soft energies}, series = {Proceedings of SPIE}, volume = {2022}, booktitle = {Proceedings of SPIE}, number = {12181}, publisher = {SPIE}, organization = {Osservatorio Astronomico di Brera}, issn = {0277-786X}, doi = {doi: 10.1117/12.2629940}, pages = {121814S-1 -- 121814s-7}, year = {2022}, abstract = {The optical properties of X-ray mirror samples are commonly measured using diffractometers based on laboratory sources; like the Bede D1 diffractometer operating at INAF-OAB. This instrument can generate a collimated X-ray beam up to 60 keV, even though the most interesting energy region for x-ray astronomy applications is usually below 10 keV. In the softest part of this range (below 6 keV), high X-ray absorption in air hinders a full and precise characterization of optical components. In this work, we present an upgrade of the Bede D1 diffractometer that extends the operative range of the instrument below 6 keV; this is done by maximizing the flux at lowest energies and by reducing absorption by means of a helium-rich atmosphere. The upgraded instrument will be used for the tests of X-ray mirrors with innovative soft X-ray coatings, with potential application to the next generation X-ray telescopes (such as ATHENA and eXTP).}, subject = {R{\"o}ntgenspiegel}, language = {en} } @article{WisselFreudenmannCichockaetal.2024, author = {Wissel, Julian and Freudenmann, Dominic and Cichocka, Magdalena Ola and P{\"o}hl, Almut and Stephan-Hofmann, Iris and R{\"o}cke, Nicole and P{\´e}rez, Nicol{\´a}s and D{\"o}hring, Thorsten and Stadtm{\"u}ller, Johannes and Stollenwerk, Manfred}, title = {Microstructure of highly effective platinum-iridium alloys as catalysts for hydrogen peroxide decomposition}, series = {Research on Chemical Intermediates}, volume = {50}, journal = {Research on Chemical Intermediates}, number = {11}, publisher = {Springer Science and Business Media LLC}, issn = {0922-6168}, doi = {10.1007/s11164-024-05412-4}, pages = {5385 -- 5397}, year = {2024}, subject = {Iridium}, language = {en} }