2025 Enhancing swelling kinetics of pNIPAM lyogels: The role of crosslinking, copolymerization, and solvent - Journal ArticleEckert, Kathrin ; Bonsen, Christin Jelisa ; Hajnal, Anja ; Gmeiner, Johannes ; Hasse, Jonah ; Adrian, Muhammad ; Karsten, Julian ; Kißling, Patrick ; Penn, Alexander ; Fiedler, Bodo ; Luinstra, Gerrit A. ; Smirnova, Irina Fluid Phase Equilibria 597: 114462 (2025) Open Access | Publisher DOI Vertical tubes in bubbling fluidized beds: A magnetic resonance imaging study of particle and bubble behavior - Journal ArticleRennebaum, Hannah Sophie ; Müller, Christoph ; Penn, Alexander Powder Technology 457: 120870 (2025) Open Access | Publisher DOI Advancements in Application of a 3T Vertical MRI System for Analyzing Hydrodynamics in Stirred Tank Reactors - Conference PosterLenczyk, Till ; Benders, Stefan ; Penn, Alexander Quantitative NMR Methods for Reaction and Process Monitoring, NMRPM 2025 Open Access 2024 Magnetic resonance imaging for 3D-printed structured packings - Conference PresentationRennebaum, Hannah Sophie ; Dobschall, Alina ; Benders, Stefan ; Skiborowski, Mirko ; Penn, Alexander 16th International Conference on Gas–Liquid and Gas–Liquid–Solid Reactor Engineering, GLS-16: (2024) The TUHH process imaging system - Conference Poster not in ProceedingsBenders, Stefan ; Rennebaum, Hannah Sophie ; Özdemir, Melis ; Lenczyk, Till ; Penn, Alexander 16th International Bologna Conference Magnetic Resonance in Porous Media (MRPM 2024) MRI in chemical engineering applications - Conference PresentationBenders, Stefan ; Penn, Alexander IFIP TC7 System Modeling and Optimization (2024) Magnetic resonance velocimetry of particle hydrodynamics in a three-dimensional draft tube spout-fluid bed - Journal ArticleMetzger, Jens P. ; Chen, Boyuan ; Penn, Alexander ; Guenthner, Christian ; Prüssmann, Klaas P. ; Müller, Christoph R. Chemical Engineering Journal 485: 149678 (2024) Open Access | Publisher DOI The effect of baffles on the hydrodynamics of a gas-solid fluidized bed studied using real-time magnetic resonance imaging - Journal ArticleRennebaum, Hannah Sophie ; Brummerloh, Daniel Lukas ; Benders, Stefan ; Penn, Alexander Powder Technology 432: 119114 (2024) Open Access | Publisher DOI Advancing SMART Reactors through NMR Relaxometry : Characterization of Stimuli-Responsive Lyogels - Conference PosterAdrian, Muhammad ; Eckert, Kathrin ; Serial, Maria Raquel ; Tsanda, Artyom ; Benders, Stefan ; Knopp, Tobias ; Smirnova, Irina ; Penn, Alexander 16th International Bologna Conference Magnetic Resonance in Porous Media (MRPM 2024) Open Access 2023 Magnetic resonance imaging in granular flows: An overview of recent advances - Review ArticleClarke, Daniel ; Hogendoorn, Willian ; Penn, Alexander ; Serial, Maria Raquel Particuology 101: 18-32 (2025) Open Access | Publisher DOI Computer simulation of magnetic resonance imaging of the flow of fluidized particles - Journal ArticleBordbar, Alireza ; Benders, Stefan ; Zia, Wasif ; Penn, Alexander ; Boyce, Christopher M. Industrial and Engineering Chemistry Research 62 (29): 11677–11688 (2023-07-12) Publisher DOI Magnetic resonance imaging of fluidized beds with baffles - Conference PresentationBuchholz, Hannah Sophie ; Brummerloh, Daniel Lukas ; Benders, Stefan ; Penn, Alexander Quantitative NMR Methods for Reaction and Process Monitoring (NMRPM 2023) Temperature distribution in a gas-solid fixed bed probed by rapid magnetic resonance imaging - Journal ArticleSerial, Maria Raquel ; Benders, Stefan ; Rotzetter, Perrine ; Brummerloh, Daniel Lukas ; Metzger, Jens Patrick ; Gross, Simon P. ; Nussbaum, Jennifer ; Müller, Christoph ; Prüssmann, Klaas P. ; Penn, Alexander Chemical Engineering Science 269: 118457 (2023-04-05) Publisher DOI 2022 The effect of baffles on fluidized bed hydrodynamics - A magnetic resonance imaging study - Conference PresentationBuchholz, Hannah Sophie ; Brummerloh, Daniel Lukas ; Benders, Stefan ; Penn, Alexander Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer (2022) Quantifying wall effects in fluidized beds using real-time magnetic resonance imaging - Conference Poster not in ProceedingsBrummerloh, Daniel Lukas ; Buchholz, Hannah Sophie ; Benders, Stefan ; Penn, Alexander Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022 A review on fast tomographic imaging techniques and their potential application in industrial process control - Journal ArticleHampel, Uwe ; Babout, Laurent ; Banasiak, Robert ; Schleicher, Eckhard ; Soleimani, Manuchehr ; Wondrak, Thomas ; Vauhkonen, Marko ; Lähivaara, Timo ; Tan, Chao ; Hoyle, Brian ; Penn, Alexander Sensors 22 (6): 2309 (2022) Open Access | Publisher DOI 2021 Stereo camera based in-situ monitoring of L-PBF process stability by spatter detection - Conference PaperBrummerloh, Daniel Lukas ; Jutkuhn, Dennis ; Yang, Zheng ; Penn, Alexander ; Emmelmann, Claus Advancing Precision in Additive Manufacturing (2021) CFD-DEM study of bubble properties in a cylindrical fluidized bed of Geldart Group D particles and comparison with prior MRI data - Journal ArticleXi, Kenan ; Kovar, Thomas M. ; Fullmer, William D. ; Penn, Alexander ; Musser, Jordan ; Boyce, Christopher M. Powder Technology 389: 75-84 (2021-09) Publisher DOI Mechanism of anomalous sinking of an intruder in a granular packing close to incipient fluidization - Journal ArticleTsuji, Takuya ; Penn, Alexander ; Hattori, Taisuke ; Prüssmann, Klaas P. ; Müller, Christoph ; Oshitani, Jun ; Washino, Kimiaki ; Tanaka, Toshitsugu Physical Review Fluids 6 (6): 064305 (2021-06) Publisher DOI 2020 Link between packing morphology and the distribution of contact forces and stresses in packings of highly nonconvex particles - Journal ArticleConzelmann, Nicholas ; Penn, Alexander ; Partl, Manfred N. ; Clemens, F. J. ; Poulikakos, Lily ; Müller, Christoph Rüdiger Physical Review E 6 (102): 062902 (2020-12-21) Publisher DOI Real-Time Magnetic Resonance Velocimetry and Thermometry of Gas-Solid Systems - Conference PaperRotzetter, Perrine ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger ; Penn, Alexander AIChE Annual Meeting (2020) Combined Real-Time Magnetic Resonance Imaging and Numerical Simulation of Gas Bubble Splitting and Coalescence in Fluidized Beds - Conference PaperMetzger, Jens ; Suter, Mathieu ; Penn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger AIChE Annual Meeting (2020) Asynchronous bubble pinch-off pattern arising in fluidized beds due to jet interaction : a magnetic resonance imaging and computational modeling study - Journal ArticlePenn, Alexander ; Padash, Azin ; Lehnert, M. ; Prüssmann, Klaas P. ; Müller, Christoph ; Boyce, Christopher M. Physical Review Fluids 9 (5): 094303 (2020-09-25) Open Access | Publisher DOI Regimes of jetting and bubbling in a fluidized bed studied using real-time magnetic resonance imaging - Journal ArticlePenn, Alexander ; Boyce, Christopher M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Chemical Engineering Journal (383): 123185 (2020-03-01) Publisher DOI Magnetic resonance thermometry of gas‐solid systems - Journal ArticleRotzetter, Perrine ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger ; Penn, Alexander Chemie Ingenieur Technik 9 (92): 1180-1180 (2020) Publisher DOI 2019 Wake volume of injected bubbles in fluidized beds: A magnetic resonance imaging velocimetry study - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Powder Technology (357): 428-435 (2019-12-01) Publisher DOI Characteristics of a single jet injected into an incipiently fluidized bed: A magnetic resonance imaging study - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Advanced Powder Technology 12 (30): 3146-3152 (2019-12) Publisher DOI Magnetic resonance imaging of interaction and coalescence of two bubbles injected consecutively into an incipiently fluidized bed - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Chemical Engineering Science (208): 115152 (2019-11-23) Publisher DOI Real-time imaging of granular dynamics - Conference PaperPenn, Alexander ; Boyce, Christopher M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger International Conference on Magnetic Resonance Microscopy (ICMRM 2019) Magnetic resonance imaging of single bubbles injected into incipiently fluidized beds - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Chemical Engineering Science (200): 147-166 (2019-06-08) Publisher DOI Gravitational instabilities in binary granular materials - Journal ArticleMcLaren, Christopher ; Kovar, Thomas M. ; Penn, Alexander ; Müller, Christoph Rüdiger ; Boyce, Christopher M. Proceedings of the National Academy of Sciences of the United States of America 19 (116): 9263-9268 (2019-05-07) Publisher DOI Real-time magnetic resonance imaging of fluidized beds with internals - Journal ArticlePenn, Alexander ; Boyce, Christopher M. ; Conzelmann, Nicholas ; Bezinge, Gaëtan ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Chemical Engineering Science (198): 117-123 (2019-04-28) Publisher DOI Anomalous collapse of interacting bubbles in a fluidized bed : a magnetic resonance imaging study - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Padash, Azin ; Lehnert, M. ; Prüssmann, Klaas P. ; Müller, Christoph Physical Review Fluids 3 (4): 034303 (2019-03-18) Open Access | Publisher DOI Magnetic resonance imaging of the interaction of bubbles and jets injected into fluidized beds - Conference PaperBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Padash, A. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger March Meeting of the American Physical Society (2019) Effect of liquid bridging on bubbles injected into a fluidized bed: A magnetic resonance imaging study - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Powder Technology (343): 813-820 (2019-02-01) Publisher DOI Homogeneous, High Packing Fraction Fluidization of Coarse Particles Using a Combination of Gas Flow and Vibration - Conference PaperBoyce, Christopher M. ; McLaren, Christopher ; Kovar, Thomas M. ; Penn, Alexander ; Müller, Christoph Rüdiger Fluidization XVI, Guilin, China (2019) Rayleigh-Taylor Instability in Vibrated Gas-Fluidized Particles - Conference PaperBoyce, Christopher M. ; McLaren, Christopher ; Kovar, Thomas M. ; Penn, Alexander ; Müller, Christoph Rüdiger AIChE Annual Meeting (2019) Fluidized Beds with Internals: A Real-Time Magnetic Resonance Imaging Study of Gas Bubbles and Particle Motion - Conference PaperConzelmann, Nicholas ; Boyce, Christopher M. ; Penn, Alexander ; Pruessmann, Klaas Paul Fluidization XVI, Guilin, China (2019) 2018 Magnetic resonance imaging of injected bubble and jet dynamics in fluidized beds - Conference PaperBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger AIChE Annual Meeting (2018) Magnetic resonance imaging of gas–solid fluidization with liquid bridging - Journal ArticleBoyce, Christopher M. ; Penn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger AIChE Journal 8 (64): 2958-2971 (2018-08) Publisher DOI Real-Time magnetic resonance imaging of bubble behavior and particle velocity in fluidized beds - Journal ArticlePenn, Alexander ; Boyce, Christopher M. ; Kovar, Thomas M. ; Tsuji, Takuya ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Industrial and Engineering Chemistry Research 29 (57): 9674-9682 (2018-07-25) Publisher DOI A high-performance gradient insert for rapid and short-T₂ imaging at full duty cycle - Journal ArticleWeiger, Markus ; Overweg, Johan ; Rösler, Manuela Barbara ; Froidevaux, Romain ; Hennel, Franciszek ; Wilm, Bertram Jakob ; Penn, Alexander ; Sturzenegger, Urs ; Schuth, Wout ; Mathlener, Menno ; Borgo, Martino ; Börnert, Peter ; Leussler, Christoph ; Luechinger, Roger ; Dietrich, Benjamin Emanuel ; Reber, Jonas ; Brunner, David Otto ; Schmid, Thomas M. ; Vionnet, Laetitia ; Pruessmann, Klaas Paul Magnetic Resonance in Medicine 6 (79): 3256-3266 (2018-06) Publisher DOI MRI of bubble and jet injection into fluidized beds - Conference PaperBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger NETL Workshop on Multiphase Flow Science (2018) Real-time magnetic resonance Imaging of granular dynamics - Doctoral ThesisPenn, Alexander ETH Zürich: Diss. ETH No. 24619 (2018) Publisher DOI Detection of Fluidization with Real-Time Magnetic Resonance Imaging - Conference PaperPenn, Alexander ; Boyce, Christopher M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger 8th World Congress on Particle Technology (2018) Magnetic Resonance Imaging and Modeling of Liquid-Solid Fluidization - Conference PaperBoyce, Christopher M. ; Penn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger World Congress on Particle Technology (2018) Real-time magnetic resonance imaging of gas-solid fluidization - Conference PaperPenn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Jahrestreffen Reaktionstechnik, Würzburg, Germany (2018) Im Takt des Kernspins: Blitzschnelle Bilder aus den Inneren granularer Medien - Journal ArticlePenn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger GIT Labor-Fachzeitschrift 62 (9): (2018) MRI of Anomalous Flow upon Gas Injection into Fluidized Beds - Conference Poster not in ProceedingsBoyce, Christopher M. ; Penn, Alexander ; Lehnert, M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Granular Matter Gordon Research Conference (2018) On the Mechanism of Anomalous Sphere Sinking in Apparently Fixed Particle Beds (Discrete Particle Simulation and Ultra-Fast MRI Measurement) - Conference PaperTsuji, Takuya ; Penn, Alexander ; Müller, Christoph Rüdiger ; Hattori, Taisuke ; Oshitani, Jun ; Pruessmann, Klaas Paul World Congress on Particle Technology (2018) 2017 Real-time probing of granular dynamics with magnetic resonance - Journal ArticlePenn, Alexander ; Tsuji, Takuya ; Brunner, David Otto ; Boyce, Christopher M. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Science Advances 9 (3): e1701879 (2017-09) Open Access | Publisher DOI A high-performance head and extremity insert gradient for rapid and short-T2 imaging: 200 mT/m, 1200 mT/m/ ms, and 100% duty cycle - Conference PaperWeiger, Markus ; Overweg, Johan ; Rösler, Manuela Barbara ; Froidevaux, Romain ; Hennel, Franciszek ; Wilm, Bertram Jakob ; Penn, Alexander ; Sturzenegger, Urs ; Schuth, Wout ; Mathlener, Menno ; Borgo, Martino ; Börnert, Peter ; Leussler, Christoph ; Luechinger, Roger ; Dietrich, Benjamin Emanuel ; Reber, Jonas ; Brunner, David Otto ; Schmid, Thomas M. ; Vionnet, Laetitia ; Pruessmann, Klaas Paul ESMRMB Congress (2017) Magnetic Resonance Imaging of Wet Fluidization - Conference PaperBoyce, Christopher M. ; Penn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger AIChE Annual Meeting (2017) Real-time magnetic resonance imaging of granular flows - Conference Poster not in ProceedingsPenn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Powders and grains (2017) Magnetic resonance imaging of gas-solid fluidization with liquid bridging - Conference Poster not in ProceedingsBoyce, Christopher M. ; Penn, Alexander ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger International Conference on Micromechanics of Granular Media (Powders and grains 2017) 2016 2015 2014 Correlating surface cation composition and thin film microstructure with the electrochemical performance of lanthanum strontium cobaltite (LSC) electrodes - Journal ArticleRupp, Ghislain M. ; Limbeck, Andreas ; Kubicek, Markus ; Penn, Alexander ; Stöger-Pollach, Michael ; Friedbacher, Gernot ; Fleig, Jürgen Journal of Materials Chemistry A 2 (19): 7099-7108 (2014-05-21) Open Access | Publisher DOI Electrochemical properties of La₀.₆Sr₀.₄CoO 3 - δ thin films investigated by complementary impedance spectroscopy and isotope exchange depth profiling - Journal ArticleKubicek, Markus ; Huber, Tobias M. ; Welzl, Andreas ; Penn, Alexander ; Rupp, Ghislain M. ; Bernardi, Johannes ; Stöger-Pollach, Michael ; Hutter, Herbert ; Fleig, Jürgen Solid State Ionics (256): 38-44 (2014-03-01) Open Access | Publisher DOI Parallel Magnetic Resonance Imaging of fluidized and spouted beds - Conference PaperPenn, Alexander ; Köhl, Maximilian H. ; Third, James R. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger International Workshop on Fluid-Particle Systems (2014) Magnetic resonance imaging of granular matter - Conference PaperPenn, Alexander ; Köhl, Maximilian H. ; Pruessmann, Klaas Paul ; Müller, Christoph Rüdiger Condensed Matter (2014) 2013
