@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}
}
@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}
}
@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}
}
@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}
}
@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}
}
@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}
}
@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}
}
@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}
}
@inproceedings{AuthCzarneckiBensberg2019,
  author    = {Auth, Gunnar and Czarnecki, Christian and Bensberg, Frank},
  title     = {Impact of robotic process automation on enterprise architectures},
  series = {GI Edition Proceedings Band 295 INFORMATIK 2019, Workshop-Beitr{\"a}ge},
  booktitle = {GI Edition Proceedings Band 295 INFORMATIK 2019, Workshop-Beitr{\"a}ge},
  editor    = {Draude, Claude and Lange, Martin and Sick, Bernhard and Gesellschaft f{\"u}r Informatik e.V. (GI),},
  publisher = {K{\"o}llen},
  address   = {Bonn},
  isbn      = {9783885796893},
  issn      = {1617-5468},
  doi       = {10.18420/inf2019_ws05},
  pages     = {59 -- 65},
  year      = {2019},
  abstract  = {The initial idea of Robotic Process Automation (RPA) is the automation of business processes through the presentation layer of existing application systems. For this simple emulation of user input and output by software robots, no changes of the systems and architecture is required. However, considering strategic aspects of aligning business and technology on an enterprise level as well as the growing capabilities of RPA driven by artificial intelligence, interrelations between RPA and Enterprise Architecture (EA) become visible and pose new questions. In this paper we discuss the relationship between RPA and EA in terms of perspectives and implications. As workin- progress we focus on identifying new questions and research opportunities related to RPA and EA.},
  language  = {en}
}
@inproceedings{AugensteinKuperjansLucas2002,
  author    = {Augenstein, Eckardt and Kuperjans, Isabel and Lucas, K.},
  title     = {EUSEBIA - Decision-Support-System for Technical, Economical and Ecological Design and Evaluation of Industrial Energy Systems},
  series = {ECOS 2002 : proceedings of the 15th International Conference on Efficiency, Costs, Optimization, Simulation and Environmental Impact of Energy Systems, Berlin, Germany July 3 - 5, 2002. - Vol. 1},
  booktitle = {ECOS 2002 : proceedings of the 15th International Conference on Efficiency, Costs, Optimization, Simulation and Environmental Impact of Energy Systems, Berlin, Germany July 3 - 5, 2002. - Vol. 1},
  editor    = {Tsatsaronis,, Georgios},
  publisher = {Techn. Univ., Inst. for Energy Engineering},
  address   = {Berlin},
  isbn      = {3-00-009533-0},
  pages     = {446 -- 453},
  year      = {2002},
  language  = {en}
}