Technische Universität Bergakademie Freiberg

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  • ItemOpen Access
    2D Imaging Simulation from 3D Particle Data: Extended Python Notebooks, Simulation Results
    (Technische Universität Bergakademie Freiberg, 2024-07-30) Buchwald, Thomas
    2D projection imaging techniques are simulated with 3D particle data from tomography measurements. This submission contains two distinct parts: Python notebooks to simulate 2D imaging of the particles, and the resulting simulation dataset. This dataset extends a previous one (https://doi.org/10.25532/OPARA-479) by an additional method of particle surface area determination and a larger dataset of randomly oriented projections – ten instead of the previous three. The Python notebooks were created with Jupyter Lab and Anaconda. A environment.yml file is provided that recreates the Anaconda environment. The simulation dataset that results from the provided Python notebooks is made available as CSV files or as pickled Python (pandas) DataFrames. Please refer to the included Readme for a detailed description of the files contained in the archive.
  • ItemOpen Access
    2D Imaging Simulation from 3D Particle Data: Python Notebooks, Particle Datasets, and Simulation Results
    (Technische Universität Bergakademie Freiberg, 2024-05-14) Buchwald, Thomas; Ditscherlein, Ralf
    2D projection imaging techniques are simulated with 3D particle data from tomography measurements. This submission contains three distinct parts: original particle data, Python notebooks to simulate 2D imaging of the particles, and the resulting simulation dataset. The particle data comes as STLs that have been converted from VTK particle data as provided by the PARROT database (https://parrot.tu-freiberg.de/). The STL files are *not* identical with the STLs provided by PARROT as of May 2024! The particle data folder is provided as separate archive because of its large size. The Python notebooks were created with Jupyter Lab and Anaconda. A environment.yml file is provided that recreates the Anaconda environment. The simulation dataset that results from the provided Python notebooks is made available as CSV files or as pickled Python (pandas) DataFrames. Please refer to the included Readme for a detailed description of the files contained in the archive.
  • ItemOpen Access
    Additional data: Impact of Chitosan's Degree of Deacetylation, Molecular Weight, and Crystallinity on the Photoresponsive Properties of Azobenzene-modified Films and Membranes.
    (Technische Universität Bergakademie Freiberg, 2024-11-15) von Seggern, Nils; M. Thiebes, Yannick; Niewa, Rainer; Cord-Landwehr, Stefan; Moerschbacher, Bruno; Tovar, Günter E.M.; Stegbauer, Linus
    A profound understanding of how the degree of deacetylation (DDA), polymerization degree (DP) and photoswitch concentration impact the photomodulation of properties of chitosan(CS)-based responsive materials can serve as a framework for future applications. Herein, we report responsive thin-films manufactured from chitosans with DDA ranging from 70-94% and DP between 170-3380, incorporating 10 30mol% of the light-responsive azobenzene derivative Sodium-4-[(4-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)phenyl)diazenyl]-benzenesulfonate (TEGABS). During UV-irradiation of the 10 30% TEGABS|CS thin-films, e.g. a significant increase of the indentation modulus by 10 ± 5% is observed. UV illumination leads to a decrease of the water vapor permeability (WVP), reducing it by up to 81 ± 17% compared to native state. We demonstrate that TEGABS up to 10% remains as a solid-solution in CS films with differing amount of H-aggregates depending on the DDA and DP. TEGABS in concentrations >10% in CS leads to phase separation of TEGABS crystallites with a diameter of 21 ± 8 nm. To conclude the photothermal heating by UV irradiation and the resulting water evaporation are identified as the primary driving force for the variation in mechanical properties and WVP, with photoisomerization playing a subordinate factor. These findings provide a new pathway for the design of polysaccharide-based water vapor permeable photoresponsive membranes.
  • ItemOpen Access
    Colloidal probe atomic force microscopy measurements on pristine gas bubbles, agglomerates and particle-laden gas bubbles
    (Technische Universität Bergakademie Freiberg, 2024-07-08) Nicklas, Jan
    This dataset contains experimental Atomic Force Microscopy (AFM) force-displacement measurements of poorly wetted alumina particles (colloidal probes) < 15 µm interacting with pristine gas bubbles, agglomerates and particle-laden gas bubbles (hetero-coagulates) in an aqueous environment. The data was generated in the context of the Collaborative Research Center CRC 920 (Project ID 169148856 – subproject B04) that is funded by the German Research Foundation (DFG). The data set is of interest for researches that study the agglomeration or hetero-coagulation in liquid environment, and it is expected to be of particular interest to those that are concerned with the simulation and modeling of these processes (for example by Discrete Element Method). The AFM raw data was baseline corrected to increase the accessibility of the data sets to those less familiar with the AFM. A detailed interpretation of the AFM data in this repository is found in https://doi.org/10.1021/acs.langmuir.3c01781 and https://doi.org/10.1016/j.colsurfa.2024.134660.
  • ItemOpen Access
    Controlling structural instability in the Cu$_{12-x}$Ni$_x$Sb$_4$S$_{13}$ ($x$\,=\,0, 0.05, 0.2, 0.5) tetrahedrites
    (Technische Universität Bergakademie Freiberg, 2026-01-08) Bolielyi, Oleksandr; Dobrozhan, Oleksandr; Levytskyi, Volodymyr; Tsirlin, Alexander A.; Pshenychnyi, Roman; Leithe-Jasper, Andreas; Gumeniuk, Roman
    Cu$_{12-x}$Ni$_x$Sb$_4$S$_{13}$ ($x\,=\,0, 0.05, 0.2, 0.5$) tetrahedrites were synthesized by the polyol method. Measurements of magnetic susceptibility, specific heat capacity as well as electrical and thermal transport properties indicated a structural phase transition (SPT) of 1$^{\mathrm{st}}$ order at $T_k\,=\,75-85$\,K, which is accompanied by strong changes in electronic density of states (EDOS) and entropy for $x\,=\,0, 0.05, 0.2$ whereas only weak changes were observed at $x\,=\,0.5$. However, further temperature dependent synchrotron high-resolution powder X-ray diffraction (HR PXRD) studies indicated compounds with Ni-content $x\,=\,0$ and 0.5 to remain body-centered cubic [space group (SG) $I\bar{4}3m$, $a\,\approx\,10.4(1)$\,\AA] down to 10\,K, whereas crystal structures of $x\,=\,0, 0.05$ and 0.2 became tetragonal, (SG $P\bar{4}c2$, $a_\mathrm{tetr}\,\approx\,a_\mathrm{cub}\sqrt{2}$, $c_\mathrm{tetr}\,\approx\,a_\mathrm{cub}$) below $T_k$. Comparing changes of EDOS at the Fermi level [$\Delta N^{(E_\mathrm{F})}$] deduced from magnetic and thermodynamic data with those calculated from density functional theory (DFT) assuming the validity of the rigid-band approximation, we found $\Delta N^{(E_\mathrm{F})}_\mathrm{theor}\,\approx\,0$ when compared with cubic and tetragonal arragements for Cu$_{11.5x}$Ni$_{0.5}$Sb$_4$S$_{13}$, which indicate the latter to be unstable. This study shows that SPT in tetrahedites is facilitated by the presence of minor amount of a dopant.
  • ItemOpen Access
    Correlation Velocimetry inside a model of the human airways
    (Technische Universität Bergakademie Freiberg, 2025-02-07) Bauer, Katrin; Kluwe, Moritz Niklas
    The dataset corresponds to the publication "Deterministic periodic structures in a model of the human airways" by Kluwe et al. 2025. It contains raw data obtained from an optical setup used for point-wise velocity measurements using Correlation Velocimetry in a model of human airways. The recorded data consists of stereo audio files sampling the photo-electric response of two photodiodes to the passage of tracer particles. The time lag between both signals corresponds to the mean time of flight of ensembles of particles between both detectors. Using the known distance between the detectors (272 micrometers), the mean velocity of the tracer particles can be calculated. This dataset includes the raw data evaluated and discussed in the publication.
  • ItemOpen Access
    Correlative X-ray micro-Computed Tomography (X-µCT) scans of Engineered Artificial Minerals (EnAM)
    (Technische Universität Bergakademie Freiberg, 2024-11-07) Siddique, Asim; Schröer, Laurenz
    Characterizing complex particulate materials like slag using X-ray microcomputed tomography (μCT) is challenging due to minimal grey-scale contrast from similar attenuation properties among phases and intricate microstructures. To address this problem, we developed a standardized multi-scale correlative methodology that combines μCT at different resolutions with scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray fluorescence (XRF). By scanning large samples for statistical significance and sub-samples at higher resolutions, we capture detailed microstructures. Aligning SEM-EDS data with μCT scans using inherent markers enables accurate phase segmentation. Mineral mapping from SEM-EDS can help to train segmentation models for μCT data, overcoming μCT limitations and allowing precise 3D mineralogical characterization. This approach provides a robust framework for analyzing complex slag particles. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101005611 https://excite-network.eu.
  • ItemOpen Access
    Data Archive DFDP Seismic extended 3D surface and VSP survey (Alpine Fault 3D-VSP)
    (Technische Universität Bergakademie Freiberg, 2021-03-29) Buske, Stefan; Benson, Adrian; Lindsay, Danielle; Lawton, Don; Gulley, Anton; Lepine, Patrick; Constantinou, Alexis; Savage, Martha; Bowman, Hamish; Kofman, Randolf; Kellett, Richard; Mann, Christin; Lay, Vera; Schmitt, Douglas; Hopp, Chet; Townend, John; Kleine, Franz; Bertram, Malcolm; Eccles, Jennifer; Gorman, Andrew; McNab, Andrew; Hall, Kevin; Bodenburg, Sascha Barbara
    This seismic data set was acquired in 2016 by a joint effort of several partners. Within this archive, we provide the coordinate lists and correlated data with local coordinates. A detailed field report by Townend et al. (2016) describes the field procedures and available data. Please see the included pdf-file for more details.
  • ItemOpen Access
    Dataset for "CFD Analysis of Mucus Bridge Instability and Breakup in the Vocal Folds"
    (Technische Universität Bergakademie Freiberg, 2025-08-22) Heinrich, Martin
    This dataset accompanies the research paper: Heinrich, M., Döllinger, M., and Schwarze, R. (2026). CFD Analysis of Mucus Bridge Instability and Breakup in the Vocal Folds. Physical Review Fluids, 11. https://doi.org/10.1103/qq23-l918. The archive contains OpenFOAM case setups, simulation scripts, and extracted visualization data for the multiphase Volume-of-Fluid CFD simulation of mucus bridge breakup during vocal fold phonation.
  • ItemOpen Access
    Dataset Supporting the Characterization of Slag from SOEL Interconnect Remelting
    (Technische Universität Bergakademie Freiberg, 2025-08-13) Mongoljiibuu, Shine-Od
    This dataset supports the manuscript titled “Chromium in Slag from SOEL Interconnects Remelting: Characterization and Recycling Potential”. The study focuses on characterizing the bulk composition, mineralogy, its distribution, and elemental distributions in slag generated during the remelting of Solid Oxide Electrolyzer (SOEL) interconnects. The data include X-ray Fluoroscence (XRF) data, X-ray Diffraction (XRD) pattern data, X-ray Computed Tomography (XCT) dataset, and Scanning Electron Microscopy (SEM)-based Mineral Liberation Analysis dataset.
  • ItemPublic Metadata
    DFG 465144480: Boron-free self-glazing Al₂O₃-C refractories
    (Technische Universität Bergakademie Freiberg, 2026-04-01) Roungos, Vasileios; Gehre, Patrick; Salpagarov, Eldar; Aneziris, Christos G.
    Al₂O₃-C refractories are extensively used as functional components in the continuous casting of steel. These high-duty products such as submerged entry nozzles, ladle shrouds, and monoblock stoppers contain up to 30 wt.-% carbon and present excellent mechanical, thermal and chemical properties, enabling the cost- and quality-effective implementation of the continuous casting process. Ceramic glazes are externally applied on Al₂O₃-C flow control refractory products to protect carbon from oxidation. These glazes typically contain boron. However, the increasing requirements for clean steel technology along with environmental- and health issues associated with boron compounds will make the utilization of boron-free glazes a necessity in the upcoming years. New boron-free self-glazing Al₂O₃-C formulations with sodium carbonate, wollastonite and magnesia additives were developed with the assistance of the FactSage software tool. These compositions presented a softening point in the range of 1000-1100 °C for self-glaze formation, which is the typical preheating temperature range for Al₂O₃-C functional refractory products. In addition, the influence of particle packing on their oxidation resistance was investigated, based on established particle size distribution models.
  • ItemPublic Metadata
    DFG 465144480: Impact of cyclic CIP on the oxidation resistance and physical properties of a newly developed boron-free self-glazing Al2O3-C refractory
    (Technische Universität Bergakademie Freiberg, 2026-03-31) Roungos, Vasileios; Gehre, Patrick; Brachhold, Nora; Fischer, Undine; Aneziris, Christos G.
    The impact of cyclic cold isostatic pressing (C-CIP) on the oxidation resistance and physical properties of a boron-free self-glazing Al2O3-C refractory for steel casting applications was investigated. Pulsations with amplitudes of 20, 40 and 65 MPa were thereby applied either at maximum isostatic pressure or at increasing pressure. The maximum isostatic pressures applied were 80, 100 and 150 MPa, respectively. Both cycling pressurizations improved the oxidation resistance and physical properties. Higher densities were obtained at higher cycling amplitudes, in particular when the pulsations were applied at maximum isostatic pressure. In addition, the evolution of a broader pore size distribution with peaks at pores larger than 4 μm was found. The pore size distributions of the samples pressed by C-CIP at increasing pressure were narrower, with higher peaks at smaller pore sizes in the area of 2.5 μm. It was shown that utilizing cycling pressurization enables tailoring of pore sizes in carbon-bonded refractories as well, providing a powerful tool for the material design of refractories.
  • ItemOpen Access
    Dynamic Image Analysis: Python Notebooks, Particle Datasets, and Simulation Results
    (Technische Universität Bergakademie Freiberg, 2024-08-20) Buchwald, Thomas
    This submission serves as a validation dataset for the simulation results of 2D imaging methods from 3D particle meshes. The submission contains dynamic image analysis data that can be used for validation of simulation results, Python notebooks for extraction of particles and calculation of particle characteristics, and the final results in as pickled Pandas DataFrames and CSV files. This dataset extends to previous submission: https://doi.org/10.25532/OPARA-479 and https://doi.org/10.25532/OPARA-587, which contain the 3D particle dataset and the simulation algorithm notebooks.
  • ItemOpen Access
    Filtration and Particle Discrete Data (glass beads < 160 µm) for 'Project Development of multivariant structure and process models for filter cakes, combining experimental methods of process engineering with digital computer based methods'
    (Technische Universität Bergakademie Freiberg, 2026-04-29) Löwer, Erik
    This dataset contains primary experimental data investigating the filtration behavior and particulate properties of glass particles, spherical, < 160 µm. The data was generated through separation tests conducted in accordance with the VDI 2762 guideline (cake-forming filtration). The study aims to correlate particle morphology with specific filter cake resistance within a viscous medium. Soda-lime glass (SiO2, 2.55 g/cm³) from Sigmund Lindner GmbH, was used as the disperse phase. To ensure a defined particle size distribution, the material was pre-classified to a target range of 70 to 160 µm using a Nisshin Turbo Classifier TC-15M fine air classifier. The continuous medium consisted of a binary water-glycerin mixture: Glycerin content: 24 mass percent (wt%) Additive: 25 mM potassium iodide (KI). Both chemicals were sourced in analytical grade from Carl Roth GmbH + Co. KG. Complementary 3D-characterization data, including CT scans (Computed Tomography) and segmented individual particle data, are archived in the "Parrot" database of the TU Bergakademie Freiberg (https://parrot.tu-freiberg.de/).
  • ItemOpen Access
    Filtration and Particle Discrete Data (quartz < 200 µm) for 'Project Development of multivariant structure and process models for filter cakes, combining experimental methods of process engineering with digital computer based methods'
    (Technische Universität Bergakademie Freiberg, 2026-04-29) Löwer, Erik
    This dataset contains primary experimental data investigating the filtration behavior and particulate properties of quartz particles. The data was generated through separation tests conducted in accordance with the VDI 2762 guideline (cake-forming filtration). The study aims to correlate particle morphology with specific filter cake resistance within a viscous medium. Quartz (SiO2, 2.7 g/cm³) from Strobel Quarzsand GmbH, product name BCS201, was used as the disperse phase. To ensure a defined particle size distribution, the material was pre-classified to a target range of 50 to 200 µm using a Nisshin Turbo Classifier TC-15M fine air classifier. The continuous medium consisted of a binary water-glycerin mixture: Glycerin content: 24 mass percent (wt%) Additive: 25 mM potassium iodide (KI). Both chemicals were sourced in analytical grade from Carl Roth GmbH + Co. KG. Complementary 3D-characterization data, including CT scans (Computed Tomography) and segmented individual particle data, are archived in the "Parrot" database of the TU Bergakademie Freiberg (https://parrot.tu-freiberg.de/).
  • ItemOpen Access
    Granule size and shape data from SOPAT for publication "Impact of Feed Rate and Binder Concentration on the Morphology of Spray Dried Alumina-Polymer Nano-composites"
    (Technische Universität Bergakademie Freiberg, 2025-04-24) Mitra, Rahul
    This dataset comprises in-line experimental SOPAT data from spray drying investigations of alumina and polyvinylpyrrolidone-30 composite granules. The spray drying process outcomes are documented through inline optical images of dried granules obtained via a SOPAT in-line imaging system providing maximum and minimum Feret diameter and aspect ratio information.
  • ItemPublic Metadata
    GRK 2802: Characterization of a recyclate-based MgO-steel as-sintered inert anode candidate after exposure to cryolite electrolysis
    (Technische Universität Bergakademie Freiberg, 2026-02-12) Yaroshevskyi, Serhii; Adamczyk, Alexander; Brachhold, Nora; Schmidt, Gert; Hubalkova, Jana; Gumeniuk, Roman; Charitos, Alexandros; Aneziris, Christos
    The replacement of consumable carbon anodes with oxygen-evolving inert, carbon free anodes is a key technological challenge for decarbonizing primary aluminum production. While metallic, ceramic, and cermet anodes have been extensively studied, the use of recycled raw materials remains largely unexplored. In this work, composite cermet anodes consisting of 60 vol% AISI 316L stainless steel and 40 vol% recycled MgO from spent refractories were developed and tested under galvanostatic Hall-Héroult electrolysis conditions in cryolite at 1000 °C. The as-sintered composites exhibited stable cell voltage (3.2-3.3 V) over 2 h of operation. Post-mortem SEM/EDS/EBSD analyses revealed a multilayered structure with protective Fe-oxide, Al/Cr spinel formation, corroded Mg-F-rich phases, and cryolite infiltration extending beyond 2 mm depth. While the 316L steel matrix showed relative stability, the recycled MgO fraction proved chemically reactive, generating porosity and acting as the primary pathway for melt intrusion and secondary Al2O3 precipitation. Complementary static contact corrosion tests confirmed rapid fluoridation of MgO, whereas steel grains remained intact.
  • ItemPublic Metadata
    GRK 2802: CHARACTERIZATION OF COMMERCIAL MgO-C REFRACTORY BRICKS BASED ON MgO-C RECYCLATE WITH VARYING TOTAL CARBON CONTENTS
    (Technische Universität Bergakademie Freiberg, 2025-11-26) Schramm, Alexander; Weidner, Anja; Biermann, Horst; Aneziris, Christos G.; Schemmel, Thomas
    In light of the increasing focus on the recycling of refractories, the properties of commercial MgO-C refractory bricks containing MgO C recyclate are of significant economic and ecological importance. It is essential to consider that incorporating MgO-C recyclate can lead to increased variation in the material composition and, consequently, in the properties of MgO-C grades. In the present study, two commercially available grades of MgO-C bricks containing 47.5 wt.% MgO-C recyclate were characterized. The MgO-C recyclates of both grades were taken from different sources and differed particularly in their carbon content, which resulted in different total carbon contents of both MgO-C brick grades. In addition to determining fundamental properties of both MgO-C brick grades (e. g., total carbon content, bulk density, open porosity, and cold crushing strength), XRD analysis, refractoriness under load (RUL) tests, and four-point bending tests at 1000 °C in an argon atmosphere were conducted. A lower total carbon content resulted in an increased bulk density, higher thermal expansion and increased strength. Compared to a commercial MgO-C grade made from entirely fresh raw materials, the results of the RUL and bending tests revealed no detrimental effects through the incorporation of MgO-C recyclate. Despite different total carbon contents, both MgO-C grades with recyclate exhibited improved refractoriness in the RUL tests compared to the material containing only fresh raw materials.
  • ItemPublic Metadata
    GRK 2802: Characterization of MgO-C recyclate and commercial MgO-C refractory bricks with and without Recyclate
    (Technische Universität Bergakademie Freiberg, 2025-11-13) Schramm, Alexander; Stadtmüller, Till M. J.; Hubálková, Jana; Schimpf, Christian; Wüstefeld, Christina; Schemmel, Thomas; Aneziris, Christos G.; Weidner, Anja; Biermann, Horst
    In light of the increasing focus on the recycling of refractories, the properties of commercial MgO-C refractory bricks containing MgO-C recyclate are of significant economic and ecological importance. In the present study, MgO-C recyclate and two commercially available MgO-C bricks – one grade consisting exclusively of fresh raw materials while the other containing 47.5 wt.% MgO-C recyclate – were comprehensively characterized. This involved the use of X-ray computed tomography, scanning electron microscopy, X ray fluorescence analysis, X-ray diffraction, as well as density and porosity measurements. The MgO C recyclate exhibited a heterogeneous composition consisting of MgO aggregates and contained an increased content of impurities compared to fresh MgO raw materials. The incorporation of MgO C recyclate as a raw material for commercial MgO-C bricks resulted in a decrease of the average MgO aggregate size, a higher porosity with a decrease in the median pore size and a reduced CaO/SiO2 ratio of the corresponding MgO-C brick grade. Furthermore, the MgO-C grade with 47.5 wt.% MgO-C recyclate exhibited a higher cold crushing strength, but a reduced oxidation resistance.
  • ItemPublic Metadata
    GRK 2802: Densities, Surface Tensions, and Viscosities of Molten High-Silicon Electrical Steels with Different Silicon Contents
    (Technische Universität Bergakademie Freiberg, 2025-10-24) Neubert, Lukas; Bellé, Matheus Roberto; Yamamoto, Taisei; Nishi, Tsuyoshi; Yamano, Hidemasa; Ahrenhold, Frank; Volkova, Olena
    Density, surface tension, and viscosity of various liquid electrical steels are measured at different temperatures, varying in their silicon content between 3 and 6mass%. Density and surface tension are determined using the maximum bubble pressure method, while viscosity is investigated comparatively using a vibrating finger viscometer and an oscillating crucible viscometer. The results are compared with models known from the literature. Based on this, the density of the steel [ρ] = kgm 3 and the surface tension [σ] =Nm 1 can be described as a function of temperature [θ] = °C and silicon content [Si] =mass% using the equations: ρðθ, SiÞ ¼ 1.28 θ 104.18 Si þ 9081.8, σðθ, SiÞ ¼ 10 4 ½ 0.00903 θ2 1.21494 Si2 þ 29.268 θ 1.987 Si 22334 . There is a lack of experimental data in the literature for high-temperature thermophysical properties for electrical steels. This underlines once again the novelty and significance of this study, as the determined thermophysical properties are essential for a wide range of applications. For instance, they are crucial in the production of metallic powders for additive manufacturing by atomization to adjust the properties of the powders precisely. The findings are also important for steelmaking itself, as the corrosion behavior of refractory material can be better determined.