@misc{51662, author = {{Keksel, Ewald and Ponusamy, SathishKumar}}, title = {{{Untersuchung eines neuen dynamischen- mechanischen Partikelverrundungsprozesses (Studienarbeit)}}}, year = {{2022}}, } @misc{51664, author = {{Almohammad, Ahmad and Ponusamy, SathishKumar}}, title = {{{Untersuchung der Polymer-Zerkleinerung in einer Kryo-Prallmühle (Studienarbeit)}}}, year = {{2022}}, } @article{34215, abstract = {{Clinching as a mechanical joining technique allows a fast and reliable joining of metal sheets in large-scale production. An efficient design and dimensioning of clinched joints requires a holistic understanding of the material, the joining process and the resulting properties of the joint. In this paper, the process chain for clinching metal sheets is described and experimental techniques are proposed to analyze the process-microstructure-property relationships from the sheet metal to the joined structure. At the example of clinching aluminum EN AW 6014, characterization methods are applied and discussed for the following characteristics: the mechanical properties of the sheet materials, the tribological behavior in the joining system, the joining process and the resulting material structure, the load-bearing behavior of the joint, the damage and degradation as well as the service life and crack growth behavior. The compilation of the characterization methods gives an overview on the advantages and weaknesses of the methods and the multiple interactions of material, process and properties during clinching. In addition, the results of the analyses on EN AW 6014 can be applied for parameterization and validation of simulations.}}, author = {{Kupfer, Robert and Köhler, Daniel and Römisch, David and Wituschek, Simon and Ewenz, Lars and Kalich, Jan and Weiß, Deborah and Sadeghian, Behdad and Busch, Matthias and Krüger, Jan Tobias and Neuser, Moritz and Grydin, Olexandr and Böhnke, Max and Bielak, Christian Roman and Troschitz, Juliane}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties}}}, doi = {{10.1016/j.jajp.2022.100108}}, volume = {{5}}, year = {{2022}}, } @inproceedings{52687, author = {{Bähr, Philipp and Striewe, Marius and Meschut, Gerson and Sommer, Silke}}, booktitle = {{12. Kolloquium: Gemeinsame Forschung in der Mechanischen Fügetechnik}}, title = {{{Ersatzmodellentwicklung zur Berücksichtigung der lokalen Fügeelementkinematik in mechanisch gefügten Verbindungen für die Bauteilauslegung im stahlintensiven Karosseriebau}}}, year = {{2022}}, } @article{53080, abstract = {{Quantitative speciation data for alternative fuels is highly desired to assess their emission potential and to develop and validate chemical kinetic models. In terms of substitute choices for fossil diesel are oxymethylene ethers (OMEs) strongly discussed. Due to the absence of carbon-carbon bonds, soot emis-sions from combustion of OMEs are low, but significant emissions of unregulated pollutants such as alde-hydes emerge. The combustion behavior of OME fuels with different chain lengths, OME0-4, was investigated in lam-inar premixed low-pressure flames using complementary molecular-beam mass spectrometry (MBMS) techniques. MBMS sampling provides an in-situ access directly into the reaction zone of the flame. Al-most all chemical species involved in the oxidation process can be detected and quantified simultane-ously. Neat OME0-3 flames were analyzed by electron ionization (EI) MBMS with high mass resolution ( R approximate to 3900) providing exact elementary composition. To obtain isomer-specific information, an OME1- doped hydrogen flame and a stochiometric OME4 flame were studied by double-imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy. Both, EI-MBMS detection and i2PEPICO spectroscopy, en-ables a complete overview of all intermediates. The results show a dominance of oxygenated intermediates for all measured conditions. Mole fraction profiles for the most important species are presented (i.e. formaldehyde, methanol, methyl formate and formic acid) and compared to modeling results. Hydrocarbons with more than four carbon atoms were not detected under the investigated conditions. Isomers such as ethanol/dimethyl ether (m/z = 46) and ethenol/acetaldehyde (m/z = 44) could be separated using threshold photoelectron spectra for clear iden-tification and photoionization efficiency curves for quantification. This investigation permits the discus-sion and analysis of systematic trends, including intermediate species, for the combustion of the studied series of oxymethylene ether fuels. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.}}, author = {{Gaiser, Nina and Zhang, Hao and Bierkandt, Thomas and Schmitt, Steffen and Zinsmeister, Julia and Kathrotia, Trupti and Hemberger, Patrick and Shaqiri, Shkelqim and Kasper, Tina and Aigner, Manfred and Oßwald, Patrick and Köhler, Markus}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Investigation of the combustion chemistry in laminar, low-pressure oxymethylene ether flames (OME0–4)}}}, doi = {{10.1016/j.combustflame.2022.112060}}, volume = {{243}}, year = {{2022}}, } @article{53081, abstract = {{Recent progress in molecular combustion chemistry allows for detailed investigation of the intermediate species pool even for complex chemical fuel compositions, as occur for technical fuels. This study pro-vides detailed investigation of a comprehensive set of complex alternative gasoline fuels obtained from laminar flow reactors equipped with molecular-beam sampling techniques for observation of the com-bustion intermediate species pool in homogeneous gas phase reactions. The combination of ionization techniques including double-imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy enables deeper mechanistic insights into the underlying reaction network relevant to technical fuels. The se-lected fuels focus on contemporary automotive engine application as drop-in fuels compliant to European EN 228 specification for gasoline. Therefore, potential alternative gasoline blends containing oxygenated hydrocarbons as octane improvers obtainable from bio-technological production routes, e.g., ethanol, iso- butanol, methyl tert -butyl ether (MTBE), and ethyl tert -butyl ether (ETBE), as well as a Fischer-Tropsch surrogate were investigated. The fuel set is completed by two synthetic naphtha fractions obtained from Fischer-Tropsch and methanol-to-gasoline processes alongside with a fossil reference gasoline. In total, speciation data for 11 technical fuels from two atmospheric flow reactor setups are presented. Detailed main and intermediate species profiles are provided for slightly rich ( 4) = 1.2) and lean ( 4) = 0.8) con-ditions for intermediate to high temperatures. Complementary, the isomer distribution on different mass channels, like m/z = 78 u fulvene/benzene, of four gasolines was investigated. Experimental findings are analyzed in terms of the detailed fuel composition and literature findings for molecular combustion chemistry. Influences of oxygenated fuel components as well as composition of the hydrocarbon frac-tions are examined with a particular focus on the soot precursor chemistry. This dataset is available for validation of chemical kinetic mechanisms for realistic gasolines containing oxygenated hydrocarbons.(c) 2021 The Combustion Institute. Published by Elsevier Inc. All rights reserved.}}, author = {{Zinsmeister, Julia and Gaiser, Nina and Melder, Jens and Bierkandt, Thomas and Hemberger, Patrick and Kasper, Tina and Aigner, Manfred and Köhler, Markus and Oßwald, Patrick}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{On the diversity of fossil and alternative gasoline combustion chemistry: A comparative flow reactor study}}}, doi = {{10.1016/j.combustflame.2021.111961}}, volume = {{243}}, year = {{2022}}, } @article{53084, abstract = {{AbstractThe thermal decomposition of Zr(acac)4 is studied in a SiC-microreactor on the micro-second time scale. By utilizing synchrotron radiation and photoelectron photoion coincidence spectroscopy, six important zirconium intermediates, as for instance Zr(C5H7O2)2(C5H6O2), and Zr(C5H6O2)2, are identified in the gas phase for the first time. The adiabatic ionization thresholds of intermediately formed zirconium species are estimated and the main products of their thermal decomposition, acetylacetone, acetylallene and acetone are characterized unambiguously and isomer-selectively. Based on all detected intermediates, we deduce the predominant pyrolysis pathways of the precursor in the temperature range from 400 to 900 K. Our findings are complemented by numerical simulations of the flow field in the microreactor, which show that the choice of dilution gas significantly influences the temperature profile and residence times in the microreactor, such that helium provides a more uniform flow field than argon and should preferentially be used. Graphical abstract Using a soft ionization method coupled to velocity map imaging (VMI), leads to valuable insights in the thermal decomposition of Zr(C5H7O2)4, used in the synthesis of functional nanomaterials and ceramic coatings. Thanks to the use of a microreactor, important gas}}, author = {{Grimm, Sebastian and Baik, Seung-Jin and Hemberger, Patrick and Kasper, Tina and Kempf, Andreas M. and Atakan, Burak}}, issn = {{0884-2914}}, journal = {{Journal of Materials Research}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, number = {{9}}, pages = {{1558--1575}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Insights into the decomposition of zirconium acetylacetonate using synchrotron radiation: Routes to the formation of volatile Zr-intermediates}}}, doi = {{10.1557/s43578-022-00566-6}}, volume = {{37}}, year = {{2022}}, } @article{53083, abstract = {{AbstractThe decomposition and reduction of ferrocene, an important precursor for iron chemical vapor deposition and catalyst for nanotube synthesis, is investigated in the gas‐phase. Reactive intermediates are detected to understand the underlying chemistry by using a microreactor coupled to a synchrotron light source. Utilizing soft photoionization coupled with photoelectron‐photoion coincidence detection enables us to characterize exclusive intermediates isomer‐selectively. A reaction mechanism for the ferrocene decomposition is proposed, which proceeds as a two‐step process. Initially, the molecule decomposes in a homogeneous surface reaction at temperatures <900 K, leading to products such as cyclopentadiene and cyclopentadienyl radicals that are immediately released to the gas‐phase. At higher temperatures, ferrocene rapidly decomposes in the gas‐phase, losing two cyclopentadienyl radicals in conjunction with iron. The addition of hydrogen to the reaction mixture reduces the decomposition temperature, and changes the branching ratio of the products. This change is mainly attributed to the H‐addition of cyclopentadienyl radicals on the surface, which leads to a release of cyclopentadiene into the gas‐phase. On the surface, ligand fragments may also undergo a series of catalytic H‐losses leading most probably to a high carbon content in the film. Finally, Arrhenius parameters for both global reactions are presented.}}, author = {{Grimm, Sebastian and Hemberger, Patrick and Kasper, Tina and Atakan, Burak}}, issn = {{2196-7350}}, journal = {{Advanced Materials Interfaces}}, keywords = {{Mechanical Engineering, Mechanics of Materials}}, number = {{22}}, publisher = {{Wiley}}, title = {{{Mechanism and Kinetics of the Thermal Decomposition of Fe(C5H5)2 in Inert and Reductive Atmosphere: A Synchrotron‐Assisted Investigation in A Microreactor}}}, doi = {{10.1002/admi.202200192}}, volume = {{9}}, year = {{2022}}, } @misc{54386, author = {{Engemann, Julian}}, title = {{{Studie zum Auftragsverhalten von SLS-Pulvern in Abhängigkeit ihrer Fließfähigkeit}}}, year = {{2022}}, } @misc{54388, author = {{Bettker, Dominik}}, title = {{{Inbetriebnahme eines Hochdruckkapillarrheometers zur Untersuchung gasbeladener Polymerschmelzen (Studienarbeit)}}}, year = {{2022}}, } @misc{54387, author = {{Cardinal, Daniel}}, title = {{{Vergleich zweier Messverfahren zur Bestimmung der Fließfähigkeit bei erhöhten Temperaturen}}}, year = {{2022}}, } @phdthesis{34174, abstract = {{Anforderungsänderungen sind ein wesentlicher Grund für Ineffizienzen und Projektfehlschläge in der Entwicklung komplexer technischer Systeme. Proaktives Management von Anforderungsänderungen hat das Potenzial, den Umgang mit Anforderungsänderungen effizienter zu gestalten. Dafür ist ein systematischer Ansatz erforderlich, der eine ganzheitliche Bewertung und Handhabung des Änderungsrisikos im industriellen Entwicklungskontext ermöglicht. Im Rahmen dieser Dissertation wird mit der ProMaRC-Methodik ein neuartiger Ansatz für das proaktive Management von Anforderungsänderungen vorgestellt. Die Methodik wurde in enger Zusammenarbeit mit Industrieanwender:innen aus der Automobilindustrie entwickelt und anhand von fünf Fallstudien validiert. Mittels automatisierter Abhängigkeitsanalyse auf Grundlage künstlicher Intelligenz wird der Anwendungsaufwand gegenüber bestehenden Ansätzen reduziert. Die teilautomatisierte Bewertung und Handhabung der Änderungswahrscheinlichkeit und -auswirkung erfolgt anhand eines modifizierten PageRank-Algorithmus und umfasst erstmalig alle für die Risikoanalyse relevanten Einflussfaktoren. Die Validierung belegt, dass durch die ProMaRC-Methodik eine überzeugende Kombination aus praxistauglichem Anwendungsaufwand und Vollständigkeit der Analyse erzielt wird. Damit erschließt diese Dissertation das bisher kaum beachtete Forschungsfeld des proaktiven Managements von Anforderungsänderungen und fördert eine effizientere Produktentwicklung.}}, author = {{Oleff, Christian}}, publisher = {{LibreCat University}}, title = {{{Proaktives Management von Anforderungsänderungen in der Entwicklung komplexer technischer Systeme}}}, doi = {{10.17619/UNIPB/1-1600}}, volume = {{406}}, year = {{2022}}, } @phdthesis{40518, abstract = {{In dieser Arbeit wird die Entwicklung einer dezentralen Produktionssteuerung mit digitaler Repräsentation zur Anwendung in cyber-physischen Produktionssystemen (CPPS) beschrieben. Die dezentrale Produktionssteuerung geschieht hierbei selbstorganisiert, da sie die Einlastung und Umplanung von Aufträgen sowie die Koordination zwischen den einzelnen Produktionselementen selbstständig übernimmt. Dies erlaubt die automatisierte Steuerung von CPPS. Dabei spielen die Beschäftigten in dieser Betrachtung eine wesentliche Rolle. Ihre Bedürfnisse und Wünsche werden von dem Steuerungssystem berücksichtigt. Dafür wurde das Konzept der digitalen Repräsentation von Beschäftigten entwickelt. Diese Repräsentation erlaubt den individuellen Eingriff von Beschäftigten bei Entscheidungen von dem Steuerungssystem. Das automatisierte dezentrale Steuerungssystem wurde in einer Laborumgebung, die zu einem CPPS umgebaut wurde, implementiert. Darauf basierend wurde eine zweistufige Validierung durchgeführt. Ein Teil der Validierung findet durch eine reale Umsetzung in einem Labor statt, bei der ein Vergleich zu dem vorher im Labor eingesetzten zentralen Produktionssteuerungssystem gezogen wird. Die zweite Validierung erfolgt mit Hilfe einer Simulationsumgebung. Dabei konnte die Implementierung der Selbstorganisation und eine Steigerung der Liefertreue der dezentralen Produktionssteuerung gegenüber heutzutage üblicherweise eingesetzten Verfahren nachgewiesen werden.}}, author = {{Pöhler, Alexander}}, publisher = {{LibreCat University}}, title = {{{Automatisierte dezentrale Produktionssteuerung für cyber-physische Produktionssysteme mit digitaler Repräsentation der Beschäftigten}}}, doi = {{10.17619/UNIPB/1-1642}}, year = {{2022}}, } @article{31035, abstract = {{AbstractFurther innovation in the field of selective laser sintering (SLS) is strongly connected to the availability of new materials since the market is dominated by polyamide 12 (>90%). The aim of this publication is to develop a descriptive model for the droplet formation process in a Filament Extension Atomizer to predict the applicability to exploit further polymers for the SLS process. The feasibility was tested, investigated and characterized using a “Dripping out of a nozzle” setup for uniaxial extension. The droplet formation process was then observed via high-speed camera imaging and classified for certain parameters. The experiments were carried out using semi-diluted polyethylene oxide (600–4000 kg/mol), glycerol and water solutions as model fluids. Driven by the Plateau-Rayleigh instability, different types of spherical droplets were observed and various droplet formation mechanisms demonstrated and analyzed. Based on the experimental results, a predictive model is derived to describe various essential parameters.}}, author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, issn = {{0035-4511}}, journal = {{Rheologica Acta}}, keywords = {{Rheology, SLS, Lasersintering, exensional rheology}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Model droplet formation in extensional filament stretching within a Filament Extension Atomizer}}}, doi = {{10.1007/s00397-022-01339-y}}, year = {{2022}}, } @article{36815, abstract = {{Iso-octane is frequently used as a surrogate fuel or as a component in primary reference fuel blends when low-temperature combustion strategies in engines are investigated. To develop control strategies for these engines, the reaction kinetics of iso-octane must be known starting from the low temperatures and intermediate pressures before ignition to the high temperatures and pressures of combustion. This work adds new experimental data sets to the validation data for reaction mechanism development by investigating the oxidation of iso-octane in stoichiometric mixtures in a flow reactor at pressures of p = 1, 10, and 20 bar and 473K ≤ T ≤ 973 K. The experimental data are compared to simulations with recent reaction mechanisms [Atef et al., Combustion and Flame 178, (2017), Bagheri et al., Combustion and Flame 212, (2020), Cai et al., Proceedings of the Combustion Institute 37, (2018), Fang et al., Combustion and Flame 214, (2020)]. The comparison between experimental and simulated mole fractions as function of temperature show reasonable agreement for all investigated pressures. In particular, the experimentally observed onset of low-temperature reactivity above a certain pressure, the shift of the negative temperature coefficient (NTC) regime with increasing pressure to higher temperatures, and the acceleration of the high-temperature chemistry are captured well in the simulations. Deviations between experimental and simulated results are discussed in detail for the reactivity of iso-octane and some key intermediates such as 2,2,4,4-tetramethyl-tetrahydrofuran, iso-butene and acetone at low temperatures.}}, author = {{Shaqiri, S. and Kaczmarek, D. and vom Lehn, F. and Beeckmann, J. and Pitsch, H. and Kasper, Tina}}, issn = {{2296-598X}}, journal = {{Frontiers in Energy Research}}, keywords = {{Economics and Econometrics, Energy Engineering and Power Technology, Fuel Technology, Renewable Energy, Sustainability and the Environment}}, publisher = {{Frontiers Media SA}}, title = {{{Experimental Investigation of the Pressure Dependence of Iso-Octane Combustion}}}, doi = {{10.3389/fenrg.2022.859112}}, volume = {{10}}, year = {{2022}}, } @article{36817, author = {{Hoener, Martin and Kasper, Tina}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Nitrous acid in high-pressure oxidation of CH4 doped with nitric oxide: Challenges in the isomer-selective detection and quantification of an elusive intermediate}}}, doi = {{10.1016/j.combustflame.2022.112096}}, volume = {{243}}, year = {{2022}}, } @article{36810, author = {{Knyazkov, Denis A. and Cherepanov, Andrey V. and Kiselev, Vitaly G. and Gerasimov, Ilya E. and Kasper, Tina and Shmakov, Andrey G.}}, issn = {{1540-7489}}, journal = {{Proceedings of the Combustion Institute}}, keywords = {{Physical and Theoretical Chemistry, Mechanical Engineering, General Chemical Engineering}}, publisher = {{Elsevier BV}}, title = {{{Experimental and kinetic modeling study of the positive ions in premixed ethylene flames over a range of equivalence ratios}}}, doi = {{10.1016/j.proci.2022.07.157}}, year = {{2022}}, } @article{31330, abstract = {{ Owing to the implementation of multi-material construction methods in modern lightweight construction and the associated use of adhesive bonding technology, thermally induced relative displacements of the joining partners occur during the curing process. The resulting extremely complex thermo-chemo-mechanical stresses can influence the properties of the adhesive layers and reduce the load-bearing capacity. In this study, experiments are conducted to examine the influence of process-related thermal relative displacements on the mechanical properties of adhesives. The results show an anisotropy of the mechanical properties of the pre-deformed adhesive layers, depending on the magnitude and direction of the relative displacement. }}, author = {{Beule, Felix and Teutenberg, Dominik and Meschut, Gerson}}, issn = {{0954-4070}}, journal = {{Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering}}, keywords = {{Mechanical Engineering, Aerospace Engineering}}, publisher = {{SAGE Publications}}, title = {{{Directional dependence of the mechanical properties of structural adhesive joints with curing-induced pre-deformations}}}, doi = {{10.1177/09544070221100130}}, year = {{2022}}, } @article{36814, author = {{Kaczmarek, D. and Bierkandt, T. and Rudolph, C. and Grimm, S. and Shaqiri, S. and Höner, M. and Gaiser, N. and Atakan, B. and Köhler, M. and Hemberger, P. and Kasper, Tina}}, issn = {{2666-352X}}, journal = {{Applications in Energy and Combustion Science}}, keywords = {{Fuel Technology, Energy (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Activation effect of ozone and DME on the partial oxidation of natural gas surrogates and validation of pressure-dependent ozone decomposition}}}, doi = {{10.1016/j.jaecs.2022.100107}}, year = {{2022}}, } @article{36811, author = {{Kaczmarek, Dennis and Rudolph, Charlotte and Atakan, Burak and Kasper, Tina}}, issn = {{1540-7489}}, journal = {{Proceedings of the Combustion Institute}}, keywords = {{Physical and Theoretical Chemistry, Mechanical Engineering, General Chemical Engineering}}, publisher = {{Elsevier BV}}, title = {{{Kinetic investigation of the ozone-assisted partial oxidation of fuel-rich natural gas mixtures at elevated pressure}}}, doi = {{10.1016/j.proci.2022.07.195}}, year = {{2022}}, }