@incollection{AuthCzarneckiBensbergetal.2019, author = {Auth, Gunnar and Czarnecki, Christian and Bensberg, Frank and Thor, Andreas}, title = {Digitalisierung des Forschungsprozesses aus Sicht von Forschenden - durch Serviceintegration zum pers{\"o}nlichen Forschungsinformationssystem}, series = {Hochschulen in Zeiten der Digitalisierung : Lehre, Forschung und Organisation}, booktitle = {Hochschulen in Zeiten der Digitalisierung : Lehre, Forschung und Organisation}, editor = {Barton, Thomas and M{\"u}ller, Christian and Seel, Christian}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-26617-2 (Print)}, doi = {10.1007/978-3-658-26618-9_17}, pages = {287 -- 307}, year = {2019}, abstract = {In der Diskussion {\"u}ber die Digitalisierung der Forschung spielt die Frage nach der optimalen IT-Unterst{\"u}tzung f{\"u}r Forschende eine wichtige Rolle. Forschende k{\"o}nnen heute an ihren Hochschulen bzw. Wissenschaftseinrichtungen auf ein breites Angebot interner IT-Dienstleistungen zur{\"u}ckgreifen, das auch kooperative IT-Dienste umfasst, die von mehreren Institutionen in Zusammenarbeit bereitgestellt werden. Außerhalb der eigenen Organisation und des weiteren Verbunds hat sich im Internet zudem ein breites externes Angebot an innovativen, h{\"a}ufig kostenlos nutzbaren Onlinediensten entwickelt. Neben horizontalen Onlinediensten, die sich prinzipiell an jeden Internetnutzer richten (bspw. Dropbox, Twitter, WhatsApp), nimmt auch die Zahl von vertikalen Diensten f{\"u}r wissenschaftliche bzw. Forschungszwecke immer weiter zu (bspw. GoogleScholar, ResearchGate, figshare). F{\"u}r Forschende er{\"o}ffnen sich damit vielf{\"a}ltige neue M{\"o}glichkeiten, ihren individuellen Forschungsprozess durch digitale Werkzeuge zu verbessern. Aufgrund rechtlicher, technischer und personeller Restriktionen k{\"o}nnen jedoch interne Dienstleister bei der Identifizierung, Auswahl und Nutzung externer Onlinedienste nur wenig Unterst{\"u}tzung leisten. Aus einer serviceorientierten Perspektive stehen Forschende zunehmend vor dem Problem, wie sich heterogene IT-Dienste interner und externer Anbieter in den eigenen Forschungsprozess integrieren lassen. Als L{\"o}sungsansatz skizziert das Kapitel das Konzept eines pers{\"o}nlichen Forschungsinformationssystems nach Gesichtspunkten eines digitalen Servicesystems.}, language = {de} } @article{AyalaHarrisKleefeldetal.2023, author = {Ayala, Rafael Ceja and Harris, Isaac and Kleefeld, Andreas and Pallikarakis, Nikolaos}, title = {Analysis of the transmission eigenvalue problem with two conductivity parameters}, series = {Applicable Analysis}, journal = {Applicable Analysis}, publisher = {Taylor \& Francis}, issn = {0003-6811}, doi = {10.1080/00036811.2023.2181167}, pages = {37 Seiten}, year = {2023}, abstract = {In this paper, we provide an analytical study of the transmission eigenvalue problem with two conductivity parameters. We will assume that the underlying physical model is given by the scattering of a plane wave for an isotropic scatterer. In previous studies, this eigenvalue problem was analyzed with one conductive boundary parameter whereas we will consider the case of two parameters. We prove the existence and discreteness of the transmission eigenvalues as well as study the dependence on the physical parameters. We are able to prove monotonicity of the first transmission eigenvalue with respect to the parameters and consider the limiting procedure as the second boundary parameter vanishes. Lastly, we provide extensive numerical experiments to validate the theoretical work.}, language = {en} } @techreport{AyarFielenbachGrossetal.2003, author = {Ayar, A. and Fielenbach, C. and Groß, Rolf Fritz and Holfeld, T. and Lockemann, S. and Severin, C. and Thulfaut, Christian and Hillemacher, B.}, title = {Druckkohlenstaubverbrennung von rheinischer Braunkohle : Abschlussbericht}, pages = {119 Seiten}, year = {2003}, abstract = {Im Rahmen des Forschungsschwerpunkts 3 wurde experimentell und theoretisch die NO{sub x}-Bildung und -Reduktion bei der Druckkohlenstaubverbrennung untersucht. Der zuvor beschriebene Einfluss der Kohlemahlung auf die Flamme konnte auch anhand der NO{sub x}-Messungen an der DKSF-Anlage Aachen bestaetigt werden. Waehrend mit Braunkohle im Staubfeuerungsbetrieb noch keine eindeutige Druckabhaengigkeit nachgewiesen werden konnte, haben vom Lehrstuhl durchgefuehrte NO{sub x}-Messungen an der DKSF-Anlage Dorsten im Schmelzkammerfeuerungsbetrieb mit der Steinkohle Spitzbergen zwischen 9 und 13 bar ein Absinken der Stickoxidkonzentrationen mit steigendem Druck ergeben. Fuer die rheinische Braunkohle soll dieser Druckeinfluss in den naechsten Versuchsfahrten ausfuehrlicher untersucht werden. Es wurde anhand von numerischen Simulationen zu einer Braunkohleflamme der 6. Versuchsfahrt ein Vergleich zwischen der NO{sub x}-Modellierung im Standard-FLUENT-Code und in dem mit User Defined Subroutines der international flame research foundation (IFRF), Ijmuiden, erweiterten FLUENT-Code vorgenommen. Es zeigte sich, dass bei der Modellierung der Stickoxidbildung die unterschiedlich vorhergesagten Flammentemperaturen eine entscheidende Rolle spielen. Eine genauere Analyse der NO{sub x}-Modelle im Vergleich zu Messergebnissen ist bei einer Schmelzkammerfeuerung mit einer stabilen Flamme vorzunehmen. Es wurden zusaetzlich Messungen zur Untersuchung der Kinetik homogener Gasphasenreaktionen in Rauchgasen an einem Stahlreaktor durchgefuehrt. Dabei wurde sowohl der thermisch bedingte als auch der durch zudosierte Additive katalysierte Abbau nitroser Komponenten betrachtet. Vergleichend wurden mit einem am Lehrstuhl entwickelten Programm die Kinetik beschrieben. Hierbei wird mit einer Sensitivitaetsanalyse eine Reduzierung der detaillierten Darstellung der Reaktionskinetik erreicht, die es erlaubt, mit einem CFD-Code wie FLUENT zwei- und dreidimensionale Rechnungen zum Abbau verschiedener Rauchgaskomponenten durchzufuehren. Die Uebereinstimmung zwischen ein- und zweidimensionalen Rechnungen und den Messungen ist gut.}, language = {de} } @incollection{AydinDoerenKuepper1996, author = {Aydin, I. and D{\"o}ren, Horst-Peter and K{\"u}pper, H.}, title = {Plasma-Auftragschweißen mit Wolframschmelzkarbid-haltigen Metallpulvern und ihre Einsatzgebiete}, series = {Thermische Spritzkonferenz = Thermal Spraying Conference. Erich Lugscheider [Hrsg.] DVS-Berichte 175}, booktitle = {Thermische Spritzkonferenz = Thermal Spraying Conference. Erich Lugscheider [Hrsg.] DVS-Berichte 175}, publisher = {DVS-Verlag}, address = {D{\"u}sseldorf}, isbn = {3-87155-480-4}, pages = {137 -- 142}, year = {1996}, language = {de} } @article{AyedKustererFunkeetal.2016, author = {Ayed, Anis Haj and Kusterer, Karsten and Funke, Harald and Keinz, Jan}, title = {CFD Based Improvement of the DLN Hydrogen Micromix Combustion Technology at Increased Energy Densities}, series = {American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS)}, volume = {26}, journal = {American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS)}, number = {3}, publisher = {GSSRR}, issn = {2313-4402}, pages = {290 -- 303}, year = {2016}, abstract = {Combined with the use of renewable energy sources for its production, Hydrogen represents a possible alternative gas turbine fuel within future low emission power generation. Due to the large difference in the physical properties of Hydrogen compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for Dry Low NOx (DLN) Hydrogen combustion. Thus, the development of DLN combustion technologies is an essential and challenging task for the future of Hydrogen fuelled gas turbines. The DLN Micromix combustion principle for hydrogen fuel has been developed to significantly reduce NOx-emissions. This combustion principle is based on cross-flow mixing of air and gaseous hydrogen which reacts in multiple miniaturized diffusion-type flames. The major advantages of this combustion principle are the inherent safety against flash-back and the low NOx-emissions due to a very short residence time of reactants in the flame region of the micro-flames. The Micromix Combustion technology has been already proven experimentally and numerically for pure Hydrogen fuel operation at different energy density levels. The aim of the present study is to analyze the influence of different geometry parameter variations on the flame structure and the NOx emission and to identify the most relevant design parameters, aiming to provide a physical understanding of the Micromix flame sensitivity to the burner design and identify further optimization potential of this innovative combustion technology while increasing its energy density and making it mature enough for real gas turbine application. The study reveals great optimization potential of the Micromix Combustion technology with respect to the DLN characteristics and gives insight into the impact of geometry modifications on flame structure and NOx emission. This allows to further increase the energy density of the Micromix burners and to integrate this technology in industrial gas turbines.}, language = {en} } @article{AyedKustererFunkeetal.2017, author = {Ayed, Anis Haj and Kusterer, Karsten and Funke, Harald and Keinz, Jan and Bohn, D.}, title = {CFD based exploration of the dry-low-NOx hydrogen micromix combustion technology at increased energy densities}, series = {Propulsion and Power Research}, volume = {6}, journal = {Propulsion and Power Research}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {2212-540X}, doi = {10.1016/j.jppr.2017.01.005}, pages = {15 -- 24}, year = {2017}, language = {en} } @inproceedings{AyedStrieganKustereretal.2017, author = {Ayed, Anis Haj and Striegan, Constantin J. D. and Kusterer, Karsten and Funke, Harald and Kazari, M. and Horikawa, Atsushi and Okada, Kunio}, title = {Automated design space exploration of the hydrogen fueled "Micromix" combustor technology}, pages = {1 -- 8}, year = {2017}, abstract = {Combined with the use of renewable energy sources for its production, Hydrogen represents a possible alternative gas turbine fuel for future low emission power generation. Due to its different physical properties compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for Dry Low NOx (DLN) Hydrogen combustion. This makes the development of new combustion technologies an essential and challenging task for the future of hydrogen fueled gas turbines. The newly developed and successfully tested "DLN Micromix" combustion technology offers a great potential to burn hydrogen in gas turbines at very low NOx emissions. Aiming to further develop an existing burner design in terms of increased energy density, a redesign is required in order to stabilise the flames at higher mass flows and to maintain low emission levels. For this purpose, a systematic design exploration has been carried out with the support of CFD and optimisation tools to identify the interactions of geometrical and design parameters on the combustor performance. Aerodynamic effects as well as flame and emission formation are observed and understood time- and cost-efficiently. Correlations between single geometric values, the pressure drop of the burner and NOx production have been identified as a result. This numeric methodology helps to reduce the effort of manufacturing and testing to few designs for single validation campaigns, in order to confirm the flame stability and NOx emissions in a wider operating condition field.}, language = {en} } @inproceedings{AzarDigel2019, author = {Azar, Fouad and Digel, Ilya}, title = {Utilization of fluorescence spectroscopy and neural networks in clinical analysis}, series = {3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen}, booktitle = {3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen}, editor = {Staat, Manfred and Erni, Daniel}, publisher = {Universit{\"a}t Duisburg-Essen}, address = {Duisburg}, organization = {MedTech Symposium}, isbn = {978-3-940402-22-6}, doi = {10.17185/duepublico/48750}, pages = {40 -- 41}, year = {2019}, abstract = {Fluorescence topography of human urine in combination with learning algorithms can provide a variant pattern recognition method in analytical clinical chemistry and, eventually, diagnosis.}, language = {en} } @incollection{AzatKerimkulovaMansurovetal.2020, author = {Azat, Seitkhan and Kerimkulova, Almagul R. and Mansurov, Zulkhair A. and Adekenov, Sergazy and Artmann, Gerhard}, title = {The Use of Fusicoccin as Anticancer Compound}, series = {Carbon Nanomaterials in Biomedicine and the Environment}, booktitle = {Carbon Nanomaterials in Biomedicine and the Environment}, publisher = {Jenny Stanford Publishing}, address = {New York}, isbn = {978-0-429-42864-7}, doi = {10.1201/9780429428647-8}, pages = {149 -- 172}, year = {2020}, abstract = {The problem of creation and use of sorption materials is of current interest for the practice of the modern medicine and agriculture. Practical importance is production of a biostimulant using a carbon sorbent for a significant increase in productivity, which is very relevant for the regions of Kazakhstan. It is known that a plant phytohormone—fusicoccin—in nanogram concentrations transforms cancer cells to the state of apoptosis. In this regard, there is a scientific practical interest in the development of a highly efficient method for producing fusicoccin from extract of germinated wheat seeds. According to the results of computer modeling, cleaning composite components of fusicoccin using microporous carbon adsorbents not suitable as the size of the molecule of fusicoccin more than micropores and the optimum pore size for purification of constituents of fusicoccin was determined by computer simulation.}, 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} }