Technische Universität Bergakademie Freiberg
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Research data repository of Freiberg University of Mining and Technology.
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Item Open Access 2D Imaging Simulation from 3D Particle Data: Extended Python Notebooks, Simulation Results(Technische Universität Bergakademie Freiberg, 2024-07-30) Buchwald, Thomas2D 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.Item Open 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, Ralf2D 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.Item Open 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, LinusA 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.Item Open 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, JanThis 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.Item Open Access Correlation Velocimetry inside a model of the human airways(Technische Universität Bergakademie Freiberg, 2025-02-07) Bauer, Katrin; Kluwe, Moritz NiklasThe 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.Item Open 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, LaurenzCharacterizing 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.Item Open Access Dataset for "CFD Analysis of Mucus Bridge Instability and Breakup in the Vocal Folds"(Technische Universität Bergakademie Freiberg, 2025-08-22) Heinrich, MartinThis data archive accompanies the research paper "CFD Analysis of Mucus Bridge Instability and Breakup in the Vocal Folds" by Heinrich et al. 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.Item Open Access Dataset Supporting the Characterization of Slag from SOEL Interconnect Remelting(Technische Universität Bergakademie Freiberg, 2025-08-13) Mongoljiibuu, Shine-OdThis 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.Item Open Access Dynamic Image Analysis: Python Notebooks, Particle Datasets, and Simulation Results(Technische Universität Bergakademie Freiberg, 2024-08-20) Buchwald, ThomasThis 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.Item Open 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, RahulThis 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.Item Public 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, ThomasIn 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.Item Public 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, HorstIn 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.Item Public 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, OlenaDensity, 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.Item Public Metadata GRK 2802: Effect of Oxygen on Thermophysical Properties of Molten High-Silicon Electrical Steels and Its Impact on Bubble Formation Behavior(Technische Universität Bergakademie Freiberg, 2025-10-24) Neubert, Lukas; Bellé, Matheus Roberto; Seetharaman, Sridhar; Volkova, OlenaThe presence of oxygen in liquid steels has a considerable influence on their properties. Higher oxygen concentrations are typical for unkilled melts, after tapping from the basic oxygen furnace (BOF) or during secondary metallurgy. This influences thermophysical properties, for instance, surface tension, due to the surface activity of dissolved oxygen. Processes in secondary metallurgy or the interaction of the melt with the refractory material will be different. In this study, density and surface tension of molten high-silicon electrical steels are analyzed dependent of different oxygen contents, which are comparable to industrial melts during secondary metallurgy. The maximum bubble pressure method was used, and total oxygen contents between 77 and 300 ppm were taken into consideration. The silicon content of the steels is varied between 3 and 6 mass-pct. The effect of oxygen on the bubble formation behavior during decarburization in a liquid steel melt is also discussed. The results make it possible to calculate the size of bubbles that form in a melt. These findings are transferred to the processing of electrical steels, to vacuum treatments like the RH or VOD process. Reactions such as decarburization and the dissolution behavior of alloying agents are described more precisely based on these insights.Item Public Metadata GRK 2802: Extra-carbonization of biochar pellets obtained after co-torrefaction and co-pyrolysis with bituminous coal(Technische Universität Bergakademie Freiberg, 2025-11-28) Koveria, Andrii; Zuber, Jan; Himcinschi, Cameliu; Vogt, Carla; Richter, JuliaThe paper investigates the chemical and structural changes in biochar pellets resulting from the co-torrefaction and co-pyrolysis of pine wood (Pinus sylvestris) pellets with bituminous coal at a 1:1 ratio at 300, 500, and 700 °C. At 500 °C co-pyrolysis, noticeable changes occur in biochar during co-treatment with coal, as observed by Fourier-transform infrared spectroscopy (FT-IR), graphite-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (GALDI-FT-ICR-MS), and Raman spectroscopy compared to individual pyrolysis. Proximate and ultimate analyses show an increase in carbon content and decreases in volatile matter, oxygen, and hydrogen in co-treated biochar pellets. FT-IR and van Krevelen plots indicate compounds with lower O/C ratios and fewer oxygen-rich functionalities. Raman spectroscopy shows that, at 300 and 500 °C, co-pyrolyzed biochar pellets have slightly more structural ordering and less disorder than biochar pellets from individual pyrolysis. This suggests that co-processing allows the creation of a more ordered aromatic carbon structure. GALDI-FT-ICR-MS indicates an increase in condensed aromatic hydrocarbons at the expense of lignin-like and oxygen-rich structures compared with individual pyrolysis. Specifically, 500 °C co-pyrolysis shifts biochar pellets composition toward lower O/C ratios (0–0.3); products are enriched in condensed aromatic hydrocarbons and occupy van Krevelen regions with low O/C (0–0.2) and H/C (0.4–0.8). The results demonstrate extra-carbonization effects in biochar pellets during co-pyrolysis with bituminous coal at 500 and 700 °C.Item Public Metadata GRK 2802: Extraction of Vanadium from CaO–SiO2–MgO–Al2O3 Slags Based on Vaporization of Vanadium Pentoxide(Technische Universität Bergakademie Freiberg, 2025-10-24) Neubert, Lukas; Shyrokykh, Tetiana; Tinkova, Nataliia; Seetharaman, Sridhar; Volkova, OlenaVanadium is an important micro-alloying element for various steel grades. Consequently, it is also present in the slags used in the production of those grades. During steelmaking, the vanadium vaporization from the slag is not desirable, as it increases vanadium consumption and at the same time releases toxic vapors of its higher oxides. However, the recovery of vanadium from the slag after the processing is worthwhile. In oxidic form as vanadium pentoxide (V2O5), vanadium can be extracted from the slag. In this research, the vaporization behavior of vanadium from CaO–SiO2–MgO–Al2O3 industrial slag is investigated at 1873 K. The effect of different process parameters, e.g., the pressure in the furnace chamber, the duration of the oxygen treatment of the slag, and the oxygen flow rate, is considered. The effect of P2O5 and Fe2O3 addition on the extraction of vanadium is studied. It is possible to induce formation of V2O5 gas bubbles in the slag due to the oxidation of vanadium. Thus, vanadium respectively V2O5 is extracted from the slag.Item Public Metadata GRK 2802: Fracture mechanics behavior of coarse-grained MgO-C at room and high temperature(Technische Universität Bergakademie Freiberg, 2025-11-13) Solarek, Johannes; Schramm, Alexander; Henkel, Sebastian; Weidner, Anja; Aneziris, Christos G.; Biermann, HorstThe fracture mechanical properties of coarse-grained MgO-C were investigated in four-point bending tests at single-edge V-notched beams (SEVNB) at room and high temperature. For measurement of the crack mouth opening displacement (CMOD) an optical system was used. Room temperature tests were accompanied with microstructural observations of the crack path with the use of digital image correlation to investigate the mechanisms of crack propagation and to determine the crack length. MgO-C showed stable crack propagation at room temperature as well as up to 1500°C. Increased fracture toughness KIc and work of fracture were observed in the temperature range from 700°C to 1200°C. This behavior was correlated with crack closure, quasi-plastic deformation as well as the activation of visco-plastic creep mechanisms above 1200°C. Additionally, the results were discussed in terms of Hasselman’s thermal shock parameters.Item Public Metadata GRK 2802: HIGH-TEMPERATURE COMPRESSION TESTS AND ACCOMPANYING SEM INVESTIGATIONS OF MgO-C REFRACTORIES BASED ON FRESH MgO AND RECYCLATE(Technische Universität Bergakademie Freiberg, 2025-08-27) Schramm, Alexander; Weidner, Anja; Biermann, Horst; Stadtmüller, Till M. J.; Aneziris, Christos G.; Schemmel, ThomasWith regard to the increasingly desired recycling of refractories, the properties of MgO-C containing recyclate are of high economic and ecological relevance. Two commercially available grades were studied to evaluate the influence of recyclate in MgO-C materials: MgO-C consisting only of fresh MgO as well as MgO-C with 50 wt.% recyclate. In this study, compression tests on these MgO-C materials were performed at room temperature, 1000°C and 1300°C. In order to investigate the microstructure and to identify the occurring damage mechanisms, scanning electron microscopy (SEM) investigations were carried out. The compression tests provided higher strengths at room temperature and at 1000°C for the MgO-C grade with recyclate compared to the grade with only fresh MgO and comparable strengths at 1300°C. Thus, the use of recycled agglomerates had no negative effect on the compressive strength.Item Public Metadata GRK 2802: Hochtemperatur-Biegefestigkeit von kohlenstoffgebundenem Magnesiumoxid (MgO-C) unter Einbindung von DIC(Technische Universität Bergakademie Freiberg, 2025-09-16) Schramm, Alexander; Knöchel, Lukas; Biermann, Horst; Weidner, AnjaKohlenstoffgebundenes Magnesiumoxid (MgO-C) als Vertreter der Feuerfestwerkstoffe ist als Zustellungsmaterial in Konvertern, Stahlgießpfannen und Elektrolichtbogenöfen unverzichtbar. Der Werkstoff ist in der Anwendung komplexen thermischen, mechanischen und korrosiven Beanspruchungen ausgesetzt. Die Bewertung der quasi-statischen Hochtemperaturfestigkeit ist daher von zentralem Interesse und Gegenstand der vorliegenden Studie. Vier-Punkt-Biegeversuche an kommerziellem MgO-C Feuerfestmaterial wurden in einer Hochtemperaturprüfmaschine unter Schutzgas bis 1300°C durchgeführt. Mittels digitaler Bildkorrelation (DIC) bei Raumtemperatur wurden Aussagen zu ablaufenden Schädigungsmechanismen gemacht. Die in dieser Studie durchgeführten Versuche lieferten bei erhöhten Temperaturen höhere Biegefestigkeiten als bei Raumtemperatur, was auf das Schließen von Rissen entlang der Grenzfläche zwischen MgO und kohlenstoffhaltiger Matrix zurückgeführt wird.Item Public Metadata GRK 2802: Phosphorus Partition Between Liquid Crude Steel and High-Basicity Basic Oxygen Furnace Slags Containing V2O5(Technische Universität Bergakademie Freiberg, 2025-10-24) Neubert, Lukas; Kovtun, Oleksandr; Kreschel, Thilo; Volkova, OlenaThe influence of V2O5 on the phosphorus partition between liquid crude steel and heterogenous basic oxygen furnace (BOF) slag with CaO/SiO2 = 4.2 was investigated at a temperature of 1600 C in a middle frequency induction furnace. Thereby the phosphorus transfer from ‘‘steel to slag’’ as well as from ‘‘slag to steel’’ was studied over a holding time of 60 minutes. The measured results were shown as phosphorus partition and phosphorus capacity and compared with the experimental values from the literature. It was found that V2O5 in highly basic BOF slags decreases phosphorus partition and phosphorus capacity. In addition, the resulting slags were investigated using a scanning electron microscope (SEM).
