A5075830829- Granular flow and fluidized beds
- Fluid Dynamics and Mixing
- NMR spectroscopy and applications
- Particle Dynamics in Fluid Flows
- Cyclone Separators and Fluid Dynamics
- Landslides and related hazards
- Minerals Flotation and Separation Techniques
- Advanced MRI Techniques and Applications
- Mineral Processing and Grinding
- Geotechnical and Geomechanical Engineering
- Atomic and Subatomic Physics Research
- Lattice Boltzmann Simulation Studies
- Advancements in Solid Oxide Fuel Cells
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Ultrasound and Hyperthermia Applications
- Pickering emulsions and particle stabilization
- Field-Flow Fractionation Techniques
- Seismic Imaging and Inversion Techniques
- Tunneling and Rock Mechanics
- Planetary Science and Exploration
- Heat and Mass Transfer in Porous Media
- Distributed and Parallel Computing Systems
- Electrical and Bioimpedance Tomography
- Plant Micronutrient Interactions and Effects
Universität Hamburg
2021-2024
Hamburg University of Technology
2021-2024
Institute for Biomedical Engineering
2017-2023
University of Zurich
2017-2023
ETH Zurich
2017-2023
TU Wien
2013-2014
Free University of Bozen-Bolzano
2014
Cation diffusion was investigated in La0.6Sr0.4CoO3-δ (LSC) thin films on (100) yttria stabilized zirconia the temperature range 625-800 °C. Isotopic ((86)Sr) and elemental tracers (Fe, Sm) were used to establish profiles of cations bi- multi-layered films. The analyzed by time flight-secondary ion mass spectrometry (ToF-SIMS). Grain grain boundary coefficients determined for LSC with columnar grains - along boundaries is shown be about three orders magnitude faster than grains. This could...
Purpose The goal of this study was to devise a gradient system for MRI in humans that reconciles cutting‐edge strength with rapid switching and brings up the duty cycle 100% at full continuous amplitude. Aiming advance neuroimaging short‐T 2 techniques, hardware design focused on head extremities as target anatomies. Methods A boundary element method minimization power dissipation stored magnetic energy used anatomy‐targeted coils maximally relaxed geometry constraints. relies hollow...
Real-time MRI of granular dynamics enabled by a joint optimization imaging hardware, pulse sequences, and sample properties.
Surface composition of La<sub>0.6</sub>Sr<sub>0.4</sub>CoO<sub>3−δ</sub> electrodes investigated by means a novel on-line <italic>in situ</italic> etching procedure with ICP-OES analysis.
Snapshots of particle concentration and velocity fields in bubbling gas–solid fluidized beds were acquired using magnetic resonance imaging. Using a recently developed multichannel radiofrequency receiver coil combination with fast readout techniques, adapted from medical MRI protocols, the temporal resolution was 7 18 ms for two-dimensional images fields, respectively. A cylindrical bed 190 mm diameter 300 height filled to heights 100, 150, 200 spherical 1 3 particles at ratios superficial...
Draft tube spout-fluid beds (DTSFB) are widely used in industry for processes that require intense mixing and high heat transfer between fluids solid particles. The insertion of a draft compartmentalizes slow-moving annular region from velocity flow the tube, thereby allowing accurate control particle circulation rate gas contacting time. Due to these characteristics DTSFBs popular subject experimental studies. However, opaque nature granular materials impedes visual measurement inside...
Magnetic resonance imaging is used to generate snapshots of particle concentration and velocity fields in gas–solid fluidized beds into which small amounts liquid are injected. Three regimes bed behavior (stationary, channeling, bubbling) mapped based on superficial loading. Images analyzed determine quantitatively the number bubbles, bubble diameter, height, distribution speeds under different wetting conditions. The cohesion dissipation provided by bridges cause an increase minimum...
The motion and mixing of granular media are observed in several contexts nature, often displaying striking similarities to liquids. Granular dynamics occur geological phenomena also enable technologies ranging from pharmaceuticals production carbon capture. Here, we report the discovery a family gravitational instabilities particle mixtures subject vertical vibration upward gas flow, including Rayleigh-Taylor (RT)-like instability which lighter grains rise through heavier form "fingers"...
The oxygen exchange and diffusion properties of La0.6Sr0.4CoO3 − δ thin films on yttria stabilized zirconia were analyzed by impedance spectroscopy 18O tracer experiments. investigations performed the same film samples at temperature (400 °C) in order to get complementary information two methods. Electrochemical can reveal resistive capacitive contributions such systems, but an exact interpretation spectra complex oxide electrodes is often difficult from data alone. It shown that additional...
Understanding and predicting the hydrodynamics of gas bubbles particle-laden phase in fluidized beds is essential for successful design efficient operation this type reactor. In work, we used real-time magnetic resonance imaging (MRI) to investigate effect three commonly-used baffle geometries on bubble behavior particle motion a bed model with an inner diameter 190 mm. MRI time series local density velocity were acquired study size, number, shape as well phase. The superficial was varied...
An external load on a particle packing is distributed internally through heterogeneous network of contacts. This contact force distribution determines the stability and resulting structure. Here, we investigate homogeneity in packings highly nonconvex particles both two-dimensional (2D) three-dimensional (3D) packings. A recently developed discrete element method used to model varying sphericity. Our results establish that 3D forces normal direction becomes increasingly with decreasing...
In this review we explore the recent developments in use of Magnetic Resonance Imaging (MRI) for studying granular flows. While MRI has been a valuable tool field past 40 years, advances imaging hardware, reconstruction software and particles synthesis have significantly enhanced its capabilities. This article provides an overview current challenges progress media, gives perspective possible future field.
The collapse, or reduction in size to zero volume, of bubbles injected into incipiently fluidized beds was studied using rapid magnetic resonance imaging. collapse a smaller lower bubble trailing larger upper and the one when two rose side by were found occur. Under same conditions with use finer particles injection an isolated bubble, no occurred. Thus, results indicate that gas leakage particulate phase coarse interaction promote collapse. Furthermore, also resulted rising bed surface...