Technische Universität Bergakademie Freiberg

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Research data repository of Freiberg University of Mining and Technology.

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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
    3 tomographic data sets of nano-CT measurements of a 30:70 vol-% mixture of talcum and saxolite
    (Technische Universität Bergakademie Freiberg, 2022-09-02) Ditscherlein, Ralf
    All 3 data sets are sub-volumes (Field of View approx. 65 µm) of a total sample of a particle mixture of talc and saxolite fixed in a matrix by means of epoxy resin and spacer particles (nanometre-sized carbon black particles, 150 nm equivalent spherical diameter). The primary analysis was carried out using nano-CT. The reconstructed result data are stored in the form of TIF files as sectional images (folder "rotated"). In addition, a correlation was carried out by means of EDXS analytics, the chemical information of which was used to train a segmentation algorithm. Since EDXS analysis requires a planar surface, the sample was further processed using FIB. The divergence of the ion beam produces a slight angular deviation from the perpendicular of the nano-CT volume, which necessitated a rotation of the initial volume data (--> "rotated"). The correlated result data of the particle-discrete phase information are also stored ("rotated segmented").
  • ItemOpen Access
    Additional data: From Biotechnological Residues to Biodegradable Printed Circuit Boards: Aspergillus niger Mycelium as a Structural Support Material
    (Technische Universität Bergakademie Freiberg, 2026-06-16) Stegbauer, Linus; Oehlsen, Nina; Wachsmann, Sebastian; Fauser, Dominik; Glauche, Florian; Laschat, Sabine; Selbmann, Franz; Steeb, Holger; Arki, Pal; Glöser-Chaoud, Simon
    The electronics industry urgently seeks sustainable, biodegradable alternatives to conventional substrates for printed circuit boards (PCBs) to reduce the environmental impact of electronic waste and CO2 emissions. Here, we introduce a biobased, plastic-like material derived from Aspergillus niger mycelium, AnimatRT. This material is produced from residual biomass generated in industrial citric acid production, offering a circular-economy approach. The raw mycelial biomass, consisting of spherical pellets, is processed via mold casting and air-drying, consolidating the pellets into a dense, plastic-like monolith (1.23 g cm⁻³). When formed into sheets, AnimatRT serves as a viable substrate for low-complexity PCB fabrication, allowing for direct ink writing and manual soldering of electronic components. Although its electrical properties are lower than those of FR-2 (flame retardant 2), a common, low-cost PCB laminate made of paper bonded with a phenolic resin, it remains suitable for low-frequency and proof-of-concept applications and, on average, has 56% lower embodied carbon. The mycelium boards disintegrate in water, allowing recovery of operative electronic components, whose functionality was demonstrated by re-soldering them onto a conventional PCB. The material exhibits high mechanical performance, with compressive strengths of up to 121 MPa, a flexural modulus of 2.3 GPa, and a flexural strength of 30 MPa. It is fully biodegradable (ISO 20200), redispersible in water, has low flammability, and favorable thermal insulation properties (0.21 W (mK)‑1). Heat treatment at 120°C enhances the mechanical properties, improves water resistance, and slows biodegradation. This study demonstrates the first use of biotechnology–derived A. niger mycelium as a biodegradable substrate for PCBs, addressing circularity and end-of-life challenges in electronics.
  • 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
    Corrosion and Process Analysis of a Preoxidized MgO Recyclate-based Cermet Anode in Laboratory-Scale Na-Cryolite Molten Salt Electrolysis of Aluminum at 1000 °C
    (Technische Universität Bergakademie Freiberg, 2026-07-14) Adamczyk, Alexander; Hossain, Farhan; Garcia Paz, Felipe A.; Yaroshevskyi, Serhii; Vogt, Daniel; Aneziris, Christos G.; Charitos, Alexandros
    The development of inert anodes for aluminum electrolysis remains challenging due to the high corrosivity of cryolite-based melts at 950°C–1000°C. This study investigates the corrosion and process behavior of a carbon-free MgO–steel cermet anode derived from refractory recycling during laboratory-scale Na-cryolite electrolysis at 1000°C, focusing on the effect of a pre-oxidation treatment on its corrosion behavior. In the as-sintered state, MgO grains are mechanically bonded to a 316L steel matrix with interfacial porosity that limits corrosion resistance. Pre-oxidation at 900°C for 24 h forms a dense Mg–M–O (M=Fe, Cr) oxide-rich surface layer, sealing pores and improving resistance to cryolite infiltration, albeit at the cost of reduced electrical conductivity, which translated into an overall higher cell voltage compared to the as-sintered state. During electrolysis, this layer degrades under anodic polarization, O2 evolution, and fluorination. The surface transforms into a Fe–O-rich magnetite layer (Fe3O4), while a Cr-containing oxide and an in situ Mg–Fe–O transition zone form beneath, maintaining partial protection. Overall, pre-oxidation effectively delays electrolyte penetration by converting MgO into new oxide phases but introduces conductivity losses and surface instability. The results highlight both the potential and limitations of MgO-based cermet anodes for sustainable aluminum production.
  • ItemOpen Access
    Data and simulations for green hydrogen development in Cameroon
    (Technische Universität Bergakademie Freiberg, 2026-07-14) Brumme, Anja; Golub, Alexander; Markandya, Anil; Rübbelke, Dirk
    We examine the conditions and consequences of establishing green hydrogen facilities in Cameroon. Using publicly available data, we develop a normative numerical model to identify potential trajectories for macroeconomic and environmental indicators. This dataset contains raw and processed data as well as simulation results and sensitivity analyses of key parameters.
  • 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
    Data for ultrasonic decoating of solid oxide cells (H2Giga-ReNaRe)
    (Technische Universität Bergakademie Freiberg, 2023-10-27) Kaiser, Carlo
    This file contains the raw data and data obtained from it for the publication "Ultrasonic decoating as a new recycling path to separate oxygen side layers in solid oxide cells". The file consists of: 1. an Excel document in which all quantitative data are compiled 2. a folder with all available raw images before and after ultrasonic decoating as well as binary images after segmentation for each investigated cell type
  • 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 for publication ``A bin-resolved statistical framework for comparing particle size distributions''
    (Technische Universität Bergakademie Freiberg, 2026-07-23) Mitra, Rahul
    This dataset accompanies the study introducing the Difference Significance Profile (DSP), a statistically rigorous framework for bin-resolved comparison of particle size distributions (PSDs). It contains particle-level size measurements obtained by in-line SOPAT imaging of spray-dried alumina powders, together with all processed data required to reproduce the statistical analyses presented in the associated publication. The repository includes raw particle-size data, common binned PSDs, probability differences, bin-wise DSP statistics, bootstrap calibration results, covariance matrices, and comparison-level summary statistics for two experimental scenarios: (i) powders produced under different spray-drying temperatures (120 °C and 145 °C) and (ii) repeated experiments under identical conditions (120 °C) to assess repeatability. Additionally, mercury intrusion porosimetry measurements for the two temperature conditions are provided to support the physical interpretation of the observed PSD differences. The dataset enables complete reproduction of the DSP analysis, facilitates benchmarking against alternative PSD comparison methods, and provides a reusable resource for statistical analysis of particle size distributions in particle technology and related fields.
  • 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
    Digital Supplement Michael Hohf, Dissertation (Tourmaline chemistry & Geochronology Río Blanco-Los Bronces, Chile)
    (Technische Universität Bergakademie Freiberg, 2021-05-29) Ratschbacher, Lothar
    13 datafiles, Supplement zur Dissertation Michael Hohf (Rohdaten der U-Pb und Ar/Ar Geochronologie; Mineralchemie der Tourmalinanalysen, Bor- und Schwefel-Isotopen-Daten; Karten)
  • 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.