TY - JOUR A1 - Lange, M. A. A1 - Khan, I. A1 - Opitz, P. A1 - Hartmann, J: A1 - Ashraf, M. A1 - Qurashi, A. A1 - Prädel, L. A1 - Panthöfer, M. A1 - Cossmer, Antje A1 - Pfeifer, Jens A1 - Simon, Fabian A1 - von der Au, Marcus A1 - Meermann, Björn A1 - Mondeshki, M. A1 - Tahir, M. N. A1 - Tremel, W. T1 - A Generalized Method for High-Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta3O7F and TaO2F with High Photocatalytic Activity for Oxygen Evolution from Water N2 - A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta3O7F and TaO2F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination. ii) Short reaction times (minutes rather than days) reduce the process time the energy costs by almost three orders of magnitude. iii) The oxyfluorides Ta3O7F and TaO2F are produced in gram amounts of nanoparticles. Their synthesis can be upscaled to the kg range with industrial sintering equipment. iv) SPS processing changes the catalytic properties: while conventionally prepared Ta3O7F and TaO2F show little catalytic activity, SPS-prepared Ta3O7F and TaO2F exhibit high activity for photocatalytic oxygen evolution, reaching photoconversion efficiencies up to 24.7% and applied bias to photoconversion values of 0.86%. This study shows that the materials properties are dictated by the processing which poses new challenges to understand and predict the underlying factors. KW - Fluorination KW - Oxygen evolution reaction KW - Photocatalysis KW - Spark plasma sintering KW - Tantalum oxyfluorides PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524329 DO - https://doi.org/10.1002/adma.202007434 VL - 23 IS - 20 SP - 7434 PB - Wiley‐VCH GmbH AN - OPUS4-52432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Karkhin, V. A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - A General Analytical Solution for Two-Dimensional Columnar Crystal Growth during Laser Beam Welding of Thin Steel Sheets N2 - A technique for calculating the main solidification parameters for a two-dimensional columnar crystal growth during complete penetration laser beam welding of thin steel sheets was developed. Given that the weld pool interface is described by Lamé curves (superellipses) within the horizontal plane of growth, general analytical solutions were derived for the geometry of the crystal axis and the corresponding growth rate and cross-sectional area of the crystal. A dimensionless analysis was performed to provide insights on the dependence of the solidification parameters on the shape and dimensions of the rear part of the weld pool boundary. The derived solutions were applied for the case of complete penetration laser beam keyhole welding of 2 mm thick 316L austenitic chromium-nickel steel sheets. It was shown that the reconstruction of the weld pool boundary with Lamé curves provides higher accuracy and flexibility compared to results obtained with elliptical functions. The validity of the proposed technique and the derived analytical solutions was backed up by a comparison of the obtained solutions to known analytical solutions and experimentally determined shapes and sizes of the crystals on the top surface of the sheet. The dimensions of the calculated crystal axis correlated well with the experimentally obtained results. KW - General analytical solutions KW - Two-dimensional solidification KW - Columnar crystal growth KW - Lamé curves KW - Laser beam welding PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576788 DO - https://doi.org/10.3390/app13106249 IS - 10 SP - 1 EP - 10 ET - 13 AN - OPUS4-57678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinekamp, Christian A1 - Kneiske, Sönke A1 - Guilherme Buzanich, Ana A1 - Ahrens, Mike A1 - Braun, Thomas A1 - Emmerling, Franziska T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS). KW - Catalysis KW - Heterogeneous catalysis KW - C-F bond activation KW - Postfluorination PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433 DO - https://doi.org/10.1039/D3CY01439H SN - 2044-4761 SP - 1 EP - 8 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nordholt, Niclas A1 - O'Hara, Kate A1 - Resch-Genger, Ute A1 - Blaskovich, M. A1 - Rühle, Bastian A1 - Schreiber, Frank T1 - A fluorescently labelled quaternary ammonium compound (NBD-DDA) to study resistance mechanisms in bacteria N2 - Quaternary ammonium compounds (QACs) are widely used as active agents in disinfectants, antiseptics, and preservatives. Despite being in use since the 1940s, there remain multiple open questions regarding their detailed mode-of-action and the mechanisms, including phenotypic heterogeneity, that can make bacteria less susceptible to QACs. To facilitate studies on resistance mechanisms towards QACs, we synthesized a fluorescent quaternary ammonium compound, namely N-dodecyl-N,N-dimethyl-[2-[(4-nitro-2,1,3-benzoxadiazol-7-yl)amino]ethyl]azanium-iodide (NBD-DDA). NBD-DDA is readily detected by flow cytometry and fluorescence microscopy with standard GFP/FITC-settings, making it suitable for molecular and single-cell studies. As a proof-of-concept, NBD-DDA was then used to investigate resistance mechanisms which can be heterogeneous among individual bacterial cells. Our results reveal that the antimicrobial activity of NBD-DDA against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa is comparable to that of benzalkonium chloride (BAC), a widely used QAC, and benzyl-dimethyl-dodecylammonium chloride (BAC12), a mono-constituent BAC with alkyl-chain length of 12 and high structural similarity to NBD-DDA. Characteristic time-kill kinetics and increased tolerance of a BAC tolerant E. coli strain against NBD-DDA suggest that the mode of action of NBD-DDA is similar to that of BAC. As revealed by confocal laser scanning microscopy (CLSM), NBD-DDA is preferentially localized to the cell envelope of E. coli, which is a primary target of BAC and other QACs. Leveraging these findings and NBD-DDA‘s fluorescent properties, we show that reduced cellular accumulation is responsible for the evolved BAC tolerance in the BAC tolerant E. coli strain and that NBD-DDA is subject to efflux mediated by TolC. Overall, NBD-DDA’s antimicrobial activity, its fluorescent properties, and its ease of detection render it a powerful tool to study resistance mechanisms of QACs in bacteria and highlight its potential to gain detailed insights into its mode-of-action. KW - Antimicrobial resistance KW - Bacteria KW - Disinfection KW - Biocides PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563811 DO - https://doi.org/10.3389/fmicb.2022.1023326 SN - 1664-302X IS - 13 SP - 1 EP - 13 PB - Frontiers Media CY - Lausanne AN - OPUS4-56381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Langenhan, Jennifer A1 - Jaeger, Carsten A1 - Baum, K. A1 - Simon, M. A1 - Lisec, Jan T1 - A Flexible Tool to Correct Superimposed Mass Isotopologue Distributions in GC‐APCI‐MS Flux Experiments N2 - The investigation of metabolic fluxes and metabolite distributions within cells by means of tracer molecules is a valuable tool to unravel the complexity of biological systems. Technological advances in mass spectrometry (MS) technology such as atmospheric pressure chemical ionization (APCI) coupled with high resolution (HR), not only allows for highly sensitive analyses but also broadens the usefulness of tracer‐based experiments, as interesting signals can be annotated de novo when not yet present in a compound library. However, several effects in the APCI ion source, i.e., fragmentation and rearrangement, lead to superimposed mass isotopologue distributions (MID) within the mass spectra, which need to be corrected during data evaluation as they will impair enrichment calculation otherwise. Here, we present and evaluate a novel software tool to automatically perform such corrections. We discuss the different effects, explain the implemented algorithm, and show its application on several experimental datasets. This adjustable tool is available as an R package from CRAN. KW - Mass Spectrometry KW - Isotopologue Distribution KW - Metabolic Flux KW - R package PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547318 DO - https://doi.org/10.3390/metabo12050408 VL - 12 IS - 5 SP - 1 EP - 10 PB - MDPI AN - OPUS4-54731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Goedecke, Caroline A1 - Mülow-Stollin, Ulrike A1 - Hering, S. A1 - Richter, Janine A1 - Piechotta, Christian A1 - Paul, Andrea A1 - Braun, Ulrike T1 - A first pilot study on the sorption of environmental pollutants on various microplastic materials N2 - With the drastic increase in plastic production, the input of plastic particles into the environment has become a recognised problem. Xenobiotics are able to sorb to polymer materials, and this process is further enhanced where they Encounter microplastics (plastic fragments <5 mm). In this work we studied the sorption of metformin, a type-2 diabetes drug, and difenoconazole, a fungicide, onto the virgin polymer materials polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, PP was cryo-milled and PA was treated with acid to investigate the influence of an increase in surface area and chemical modification. The material properties were also studied by dynamic scanning calorimetry (DSC), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). Sorption experiments were performed on the basis of a full factorial design examining the effect of agitation, pH value, and salinity. Experimental results showed that difenoconazole sorbs readily to all microplastics, whereas the more polar analyte metformin did not show any affinity to the materials used. For difenoconazole the governing factor in all cases is agitation, while both pH and salinity exhibited only a slight influence. The modification of polymers leads to enhanced sorption, indicating that an increase in surface area (cryo-milled PP) or inner volume (acid-treated PA) strongly favours adsorption. Moreover, long-term experiments demonstrated that the time until equilibrium is reached depends strongly on the particle size. KW - Difenoconazole KW - Metformin KW - Plastic debris KW - Polymer KW - Dynamic scanning calorimetry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402393 DO - https://doi.org/10.4172/2380-2391.1000191 SN - 2380-2391 VL - 4 IS - 1 SP - Article 1000191, 1 EP - 8 PB - Omics International CY - Los Angeles AN - OPUS4-40239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deresch, Andreas A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten T1 - A fast general spectrum model for quantitative radiography simulation N2 - One essential step on the way towards accurate quantitative simulation of radiographic testing is an accurate description of the utilized energy spectrum of X-ray photons. For use in general purpose simulation tools, the spectra of X-ray tubes have to be described by a model covering at least the intended range of applications. This range includes transmission tubes as well as direct beam tubes with varying angles of incidence and emission, for a number of typical target materials. In radiographic testing acceleration voltages frequently reach up to 450 kV for direct beam targets and up to 225 kV for transmission targets, with even higher voltages available or being developed. Currently used models are unable to cover the whole range of configurations. Here a model is presented that employs a unified approach for simulating the photon energy spectra for transmission and direct beam targets composed of arbi-trary homogeneous materials. In order to achieve this, a detailed model of electron transport within the target is employed. The validity of the developed model is shown through comparisons with Monte Carlo simulations as well as measurements for a number of different configurations. T2 - 19th World Conference on Nondestructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Measurements KW - X-ray spectra KW - Simulation KW - Electron transport PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365959 SN - 978-3-940283-78-8 VL - 158 SP - 1 EP - 7 PB - DGZfP CY - Berlin, Germany AN - OPUS4-36595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ho, Y.T. A1 - Adriani, G A1 - Beyer, Sebastian A1 - Nhan, P.-T. A1 - Kamm, R. D. A1 - Kah, J.C.Y. T1 - A facile method to probe the vascular permeability of nanoparticles in nanomedicine applications N2 - The effectiveness of nanoparticles (NP) in nanomedicine depends on their ability to extravasate from vasculature towards the target tissue. This is determined by their permeability across the endothelial barrier. Unfortunately, a quantitative study of the diffusion permeability coefficients (Pd) of NPs is difficult with in vivo models. Here, we utilize a relevant model of vascular-tissue interface with tunable endothelial permeability in vitro based on microfluidics. Human umbilical vein endothelial cells (HUVECs) grown in microfluidic devices were treated with Angiopoietin 1 and cyclic adenosine monophosphate (cAMP) to vary the Pd of the HUVECs monolayer towards fluorescent polystyrene NPs (pNPs) of different sizes, which was determined from image analysis of their fluorescence intensity when diffusing across the monolayer. Using 70 kDa dextran as a probe, untreated HUVECs yielded a Pd that approximated tumor vasculature while HUVECs treated with 25 μg/mL cAMP had Pd that approximated healthy vasculature in vivo. As the size of pNPs increased, its Pd decreased in tumor vasculature, but remained largely unchanged in healthy vasculature, demonstrating a trend similar to tumor selectivity for smaller NPs. This microfluidic model of vascular-tissue interface can be used in any laboratory to perform quantitative assessment of the tumor selectivity of nanomedicine-based systems. KW - Nanoparticle PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397053 DO - https://doi.org/10.1038/s41598-017-00750-3 SN - 2045-2322 VL - 7 IS - 1 SP - Article 707, 1 EP - 13 PB - Macmillan AN - OPUS4-39705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Milks, A. A1 - Lehmann, J. A1 - Leder, D. A1 - Sietz, M. A1 - Koddenberg, T. A1 - Böhner, U. A1 - Wachtendorf, Volker A1 - Terberger, T. T1 - A double-pointed wooden throwing stick from Schöningen, Germany: Results and new insights from a multianalytical study N2 - The site of Schöningen (Germany), dated to ca. 300,000 years ago, yielded the earliest large-scale record of humanly-made wooden tools. These include wooden spears and shorter double-pointed sticks, discovered in association with herbivores that were hunted and butchered along a lakeshore. Wooden tools have not been systematically analysed to the same standard as other Palaeolithic technologies, such as lithic or bone tools. Our multianalytical study includes micro-CT scanning, 3-dimensional microscopy, and Fourier transform infrared spectroscopy, supporting a systematic technological and taphonomic analysis, thus setting a new standard for wooden tool analysis. In illustrating the biography of one of Schöningen’s double-pointed sticks, we demonstrate new human behaviours for this time period, including sophisticated woodworking techniques. The hominins selected a spruce branch which they then debarked and shaped into an aerodynamic and ergonomic tool. They likely seasoned the wood to avoid cracking and warping. After a long period of use, it was probably lost while hunting, and was then rapidly buried in mud. Taphonomic alterations include damage from trampling, fungal attack, root damage and compression. Through our detailed analysis we show that Middle Pleistocene humans had a rich awareness of raw material properties, and possessed sophisticated woodworking skills. Alongside new detailed morphometrics of the object, an ethnographic review supports a primary function as a throwing stick for hunting, indicating potential hunting strategies and social contexts including for communal hunts involving children. The Schöningen throwing sticks may have been used to strategically disadvantage larger ungulates, potentially from distances of up to 30 metres. They also demonstrate that the hominins were technologically capable of capturing smaller fast prey and avian fauna, a behaviour evidenced at contemporaneous Middle Pleistocene archaeological sites. KW - FTIR KW - Stone Age KW - Middle Pleistocene KW - Throwing-stick KW - Wood KW - Micro-CT scanning KW - 3-dimensional microscopy PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580012 DO - https://doi.org/10.1371/journal.pone.0287719 SN - 1932-6203 VL - 18 IS - 7 SP - 1 EP - 32 PB - PLOS CY - San Francisco, California, US AN - OPUS4-58001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ehlert, Christopher A1 - Holzweber, Markus A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Saalfrank, Peter T1 - A detailed assignment of NEXAFS resonances of imidazolium based ionic liquids N2 - In Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy X-Ray photons are used to excite tightly bound core electrons to low-lying unoccupied orbitals of the system. This technique offers insight into the electronic structure of the system as well as useful structural information. In this work, we apply NEXAFS to two kinds of imidazolium based ionic liquids ([CnC₁im]⁺[NTf₂]⁻ and [C₄C₁im]⁺[I]⁻). A combination of measurements and quantum chemical calculations of C K and N K NEXAFS resonances is presented. The simulations, based on the transition potential density functional theory method (TP-DFT), reproduce all characteristic features observed by the experiment. Furthermore, a detailed assignment of resonance features to excitation centers (carbon or nitrogen atoms) leads to a consistent interpretation of the spectra. KW - Ionic liquids KW - NEXAFS KW - DFT spectrum simulations PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367223 DO - https://doi.org/10.1039/c5cp07434g SN - 1463-9076 SN - 1463-9084 VL - 18 IS - 12 SP - 8654 EP - 8661 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-36722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oster, Simon A1 - Breese, Philipp Peter A1 - Ulbricht, Alexander A1 - Mohr, Gunther A1 - Altenburg, Simon T1 - A deep learning framework for defect prediction based on thermographic in-situmonitoring in laser powder bed fusion N2 - The prediction of porosity is a crucial task for metal based additive manufacturing techniques such as laser powder bed fusion. Short wave infrared thermography as an in-situ monitoring tool enables the measurement of the surface radiosity during the laser exposure. Based on the thermogram data, the thermal history of the component can be reconstructed which is closely related to the resulting mechanical properties and to the formation of porosity in the part. In this study, we present a novel framework for the local prediction of porosity based on extracted features from thermogram data. The framework consists of a data pre-processing workflow and a supervised deep learning classifier architecture. The data pre-processing workflow generates samples from thermogram feature data by including feature information from multiple subsequent layers. Thereby, the prediction of the occurrence of complex process phenomena such as keyhole pores is enabled. A custom convolutional neural network model is used for classification. Themodel is trained and tested on a dataset from thermographic in-situ monitoring of the manufacturing of an AISI 316L stainless steel test component. The impact of the pre-processing parameters and the local void distribution on the classification performance is studied in detail. The presented model achieves an accuracy of 0.96 and an f1-Score of 0.86 for predicting keyhole porosity in small sub-volumes with a dimension of (700 × 700 × 50) μm3. Furthermore, we show that pre-processing parameters such as the porosity threshold for sample labeling and the number of included subsequent layers are influential for the model performance. Moreover, the model prediction is shown to be sensitive to local porosity changes although it is trained on binary labeled data that disregards the actual sample porosity. KW - Laser Powder Bed Fusion (PBF-LB/M, L-PBF) KW - Selective Laser Melting (SLM) KW - SWIR thermography KW - Online monitoring KW - Flaw detection KW - Machine learning KW - Convolutional neural networks (CNN) PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575148 DO - https://doi.org/10.1007/s10845-023-02117-0 SN - 0956-5515 SP - 1 EP - 20 PB - Springer AN - OPUS4-57514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Villajos Collado, José Antonio A1 - Bienert, M. A1 - Gugin, Nikita A1 - Emmerling, Franziska A1 - Maiwald, Michael T1 - A database to select affordable MOFs for volumetric hydrogen cryoadsorption considering the cost of their linkers N2 - Physical adsorption at cryogenic temperature (cryoadsorption) is a reversible mechanism that can reduce the pressure of conventional compressed gas storage systems. Metal–organic framework (MOF) materials are remarkable candidates due to the combination of high specific surface area and density which, in some cases, provide a high volumetric storage capacity. However, such extensive use of MOFs for this application requires the selection of affordable structures, easy to produce and made from feasible metallic and organic components. Herein, we introduce a MOF database detailing the crystallographic and porous properties of 3600 existing MOFs made from industrially relevant metals and their organic composition. The comparison of the available minimum costs of linkers allowed the creation of a database to select affordable structures with high potential for volumetric hydrogen storage by cryoadsorption, considering their composition based on individual or mixed building blocks. A user inter� face, available online, facilitates the selection of MOFs based on the properties or names of structures and linkers. KW - MOF´s PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583619 DO - https://doi.org/10.1039/d3ma00315a VL - 4 IS - 18 SP - 4226 EP - 4237 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58361 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fernandez-Menendez, L. J. A1 - Mendez-Lopez, C. A1 - Abad Andrade, Carlos Enrique A1 - Fandino, J. A1 - Gonzalez-Gago, C. A1 - Pisonero, J. A1 - Bordel, N. T1 - A critical evaluation of the chlorine quantification method based on molecular emission detection in LIBS N2 - The entire process involving the determination of Cl by molecular emission detection in Laser-Induced Breakdown Spectroscopy (LIBS) is thoroughly studied in this paper. This critical evaluation considers how spectra are normalized, how interferences from other molecular species signals are removed, and how signal integration is applied. Moreover, a data treatment protocol is proposed to achieve reliable and accurate Cl determination from the CaCl molecular spectral signal, not requiring the use of more complex numerical approaches. Calcium chloride dihydrate (CaCl2⋅2H2O) and high purity anhydrite samples (CaSO4) are used to optimize the acquisition conditions and data treatment of CaCl emission signal. Using the developed protocol, calibration curves for Cl, covering the concentration range from 0 μg/g to 60,000 μg/g of Cl, are successfully achieved. Finally, the suitability of the proposed methodology for Cl determination is successfully applied in industrial gypsum waste samples, where the results obtained by LIBS are validated using high-resolution molecular absorption spectroscopy (HR-CS-MAS) and potentiometric titration. KW - Laser induced breakdown Spectrocopy (LIBS) KW - Molecular spectra KW - Chlorine determination KW - CaCl emission bands KW - Industrial gypsum PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544292 DO - https://doi.org/10.1016/j.sab.2022.106390 SN - 0584-8547 VL - 190 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-54429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Getenet, M. A1 - Garcia-Ruiz, J. M. A1 - Otálora, F. A1 - Emmerling, Franziska A1 - Al-Sabbagh, Dominik A1 - Verdugo-Escamilla, E. T1 - A comprehensive methodology for monitoring evaporitic mineral precipitation and hydrochemical evolution of saline lakes: The case of Lake Magadi soda brine (East African Rift Valley, Kenya) N2 - Lake Magadi, East African Rift Valley, is a hyperalkaline and saline soda lake highly enriched in Na+, K+, CO32–, Cl–, HCO3–, and SiO2 and depleted in Ca2+ and Mg2+, where thick evaporite deposits and siliceous sediments have been forming for 100 000 years. The hydrogeochemistry and the evaporite deposits of soda lakes are subjects of growing interest in paleoclimatology, astrobiology, and planetary sciences. In Lake Magadi, different hydrates of sodium carbonate/bicarbonate and other saline minerals precipitate. The precipitation sequence of these minerals is a key for understanding the hydrochemical evolution, the paleoenvironmental conditions of ancient evaporite deposits, and industrial crystallization. However, accurate determination of the precipitation sequence of these minerals was challenging due to the dependency of the different hydrates on temperature, water activity, pH and pCO2, which could induce phase transformation and secondary mineral precipitation during sample handling. Here, we report a comprehensive methodology applied for monitoring the evaporitic mineral precipitation and hydrochemical evolution of Lake Magadi. Evaporation and mineral precipitations were monitored by using in situ video microscopy and synchrotron X-ray diffraction of acoustically levitated droplets. The mineral patterns were characterized by ex situ Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. Experiments were coupled with thermodynamic models to understand the evaporation and precipitation-driven hydrochemical evolution of brines. Our results closely reproduced the mineral assemblages, patterns, and textural relations observed in the natural setting. Alkaline earth carbonates and fluorite were predicted to precipitate first followed by siliceous sediments. Among the salts, dendritic and acicular trona precipitate first via fractional crystallization─reminiscent of grasslike trona layers of Lake Magadi. Halite/villiaumite, thermonatrite, and sylvite precipitate sequentially after trona from residual brines depleted in HCO3–. The precipitation of these minerals between trona crystals resembles the precipitation process observed in the interstitial brines of the trona layers. Thermonatrite precipitation began after trona equilibrated with the residual brines due to the absence of excess CO2 input. We have shown that evaporation and mineral precipitation are the major drivers for the formation of hyperalkaline, saline, and SiO2-rich brines. The discrepancy between predicted and actual sulfate and phosphate ion concentrations implies the biological cycling of these ions. The combination of different in situ and ex situ methods and modeling is key to understanding the mineral phases, precipitation sequences, and textural relations of modern and ancient evaporite deposits. The synergy of these methods could be applicable in industrial crystallization and natural brines to reconstruct the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and extraterrestrial planets. KW - Crystallization KW - Precipitation KW - Crystals KW - Evaporation KW - Minerals PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546712 DO - https://doi.org/10.1021/acs.cgd.1c01391 SN - 1528-7483 VL - 22 IS - 4 SP - 2307 EP - 2317 PB - ACS Publications CY - Washington, DC AN - OPUS4-54671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tsamos, Athanasios A1 - Evsevleev, Sergei A1 - Fioresi, Rita A1 - Faglioni, Francesco A1 - Bruno, Giovanni T1 - A Complete Strategy to Achieve High Precision Automatic Segmentation of Challenging Experimental X‐Ray Computed Tomography Data Using Low‐Resemblance Synthetic Training Data N2 - It is shown that preconditioning of experimental X‐ray computed tomography (XCT) data is critical to achieve high‐precision segmentation scores. The challenging experimental XCT datasets and deep convolutional neural networks (DCNNs) are used that are trained with low‐resemblance synthetic XCT data. The material used is a 6‐phase Al–Si metal matrix composite‐reinforced with ceramic fibers and particles. To achieve generalization, in our past studies, specific data augmentation techniques were proposed for the synthetic XCT training data. In addition, two toolsets are devised: (1) special 3D DCNN architecture (3D Triple_UNet), slicing the experimental XCT data from multiple views (MultiView Forwarding), the i.S.Sy.Da.T.A. iterative segmentation algorithm, and (2) nonlocal means (NLM) conditioning (filtering) for the experimental XCT data. This results in good segmentation Dice scores across all phases compared to more standard approaches (i.e., standard UNet architecture, single view slicing, standard single training, and NLM conditioning). Herein, the NLM filter is replaced with the deep conditioning framework BAM SynthCOND introduced in a previous publication, which can be trained with synthetic XCT data. This leads to a significant segmentation precision increase for all phases. The proposed methods are potentially applicable to other materials and imaging techniques. KW - Automatic Segmentation KW - XCT KW - Artificial Intelligence KW - Synthetic Training Data KW - i.S.Sy.Da.T.A. KW - BAM SynthMAT KW - BAM SynthCOND KW - Triple UNet KW - Convolutional Neural Network (DCNN) PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590912 DO - https://doi.org/10.1002/adem.202301030 SN - 1438-1656 VL - 26 IS - 2 SP - 1 EP - 9 PB - Wiley online library AN - OPUS4-59091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Campari, Alessandro A1 - Konert, Florian A1 - Sobol, Oded A1 - Alvaro, Antonio T1 - A comparison of vintage and modern X65 pipeline steel using hollow specimen technique for in-situ hydrogen testing N2 - The transition toward a hydrogen-based economy requires a widespread transport and distribution network, and repurposed natural gas pipelines are a viable option. An assessment of the hydrogen-induced degradation of pipeline steels is needed to inject H2 gas into the existing infrastructure safely. The conservative and standardized method consists of in-situ tensile tests in an autoclave filled with high-pressure hydrogen gas. A proposed alternative method involves using a hollow specimen as containment volume and applying the gas pressure in the inner cavity. This technique has lower costs and shorter test preparation time but is not standardized yet. This study aims to evaluate and compare the tensile properties of API 5L X65 pipeline steel in two states: vintage and modern. The influence of the surface roughness is investigated through parallel tests with drilled and reamed specimens. Hydrogen tests are compared with reference tests in an inert environment. A significant hydrogen-induced decrease in tensile properties is observed, and no significant difference between vintage and modern X65 can be drawn. The reduction in tensile properties is more significant in specimens with higher inner surface roughness. The evaluation of surface conditions appears crucial when assessing the HE susceptibility of hydrogen transport and storage equipment. KW - Hydrogen embrittlement KW - Hollow specimen technique KW - Pipeline steel KW - SSRT PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603013 DO - https://doi.org/10.1016/j.engfailanal.2024.108530 VL - 163 SP - 1 EP - 15 PB - Elsevier Ltd. AN - OPUS4-60301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Boschmann Käthler, C. A1 - Ebell, Gino A1 - Keßler, S. A1 - Schiegg, Y, A1 - Dauberschmidt, C. A1 - Angst, U. M. T1 - A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete - Particular consideration of 12% chromium steel N2 - The critical chloride content C(crit) is an indicator for the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content C(crit) of mild and an alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests using more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, with the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing. KW - Chloride‐induced corrosion KW - Critical chloride content KW - Reinforced concrete KW - Testing methods PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529751 DO - https://doi.org/10.1002/maco.202112826 SN - 0947-5117 N1 - This article has been published in 2021 as an "Early View" version with the DOI 10.1002/maco.202112609. VL - 73 IS - 3 SP - 306 EP - 325 PB - Wiley-VCH CY - Weinheim AN - OPUS4-52975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Boehm, Rainer A1 - Perez-Alonso, M. T1 - A comparison between ASTM E588 and SEP 1927 relating resolution limits at determination of the purity grade N2 - With increased usage of highly demanded, modern materials on safety relevant parts (e.g. railway wheel sets, generator shafts, turbine disks, medical implants, etc.) comprehensive analyses regarding the quality of the material are requested. This gives a focus to non-destructive methods using ultrasound immersion tank testing for classifying the degree of purity. Two autonomous standards, ASTM E588 and SEP 1927, have been established for the definition, execution and evaluation for this high resolution ultrasonic measurements on steel products. The propagation of ultrasonic waves and the resulting sound field are strongly dependent on the acoustical properties of the inspected material and the geometry of probes and specimen. The definition of the measurement setup and the evaluation methods appear to differ significantly in the given standards. ASTM E588 and SEP 1927 prescribe the requirement for surface roughness and probe selection, are using threshold based methods for cleanliness detection, but differ in computation for the degree of purity. This has been the motivation for a comparison between both standards with the main focus on amplitude depth dependency and overall spatial resolution taking the influence of different material characteristics, geometry of the specimen and sound fields into account. A performance comparison between the use of non-focusing and focusing probes respective to the threshold based detection will be presented in this contribution. In addition, the usage of complex reconstruction algorithms (e.g. SAFT, echo tomography) is compared with the traditional approaches of inclusion detection and estimation of the degree of purity T2 - 19th World Conference on Non-Destructive Testing 2016 CY - Munich, Germany DA - 13.06.2016 KW - Ultrasonic immersion tank testing KW - Purity grade KW - Material characterisation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-382972 SP - Paper X15, 1 EP - 10 AN - OPUS4-38297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumm, A. A1 - Martin, E. A1 - Beaumont, M. A1 - Ewert, Uwe A1 - Kolkoori, Sanjeevareddy A1 - Zscherpel, Uwe A1 - Wrobel, Norma A1 - Redmer, Bernhard T1 - A comparative study on the performance of digital detector systems for high energy applications N2 - For cast components reaching or exceeding total material thicknesses of 150mm, high energy sources such as linear accelerators or Betatrons are required in order to obtain reasonable exposure times. In this study, the performance of digital detector systems, involving imaging plates (IP) and digital detector arrays (DDA), was evaluated with respect to the testing class B requirements as formulated in the standard EN ISO 17636-2. As a reference, traditional radiographic film and a Cobalt-60 source was used. With film exposures, testing class B was achieved with Co-60 and Betatron (7.5 MV) at longer exposure times. The preliminary results show that the testing class B was not obtained with the examined digital detector arrays (DDA) and the high resolution imaging plates (IP) , even at 40, 60 and 80 minutes exposure time with a 7.5 MV Betatron. Class A was achieved using high resolution imaging plates with optimized metal filters between object and IPs and a high resolution DDA with intermediate Cu filters. Class A was also achieved applying a DDA with lower basic spatial resolution than required by Table B.13 of EN ISO 17636-2, but using the compensation principle as described in this standard. The next generation of digital detector arrays might potentially be able to obtain class B performance with the expected spatial resolution and sensitivity improvements. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Radiography KW - Image quality KW - Betatron KW - Digital detector array (DDA) KW - Casting KW - Standards KW - High energy radiography KW - Comparison of detectors KW - Steel weldment PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323075 UR - https://www.ndt.net/?id=16394 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 6 PB - NDT.net CY - Kirchwald AN - OPUS4-32307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezhov, Alexander A1 - Kulisch, D. A1 - Goncharov, A. A1 - Zhutovsky, S. T1 - A Comparative Study of Factors Influencing Hydration Stoppage of Hardened Cement Paste N2 - There is no consensus on which hydration stoppage method is optimal to preserve the microstructure and mineral composition of samples, especially considering the specific aspects of different testing methods, such as TGA, MIP, or XRD. This paper presents a quantitative comparison between the most popular hydration stoppage strategies and parameters such as the sample piece size, the soaking time in a solvent, and the type, as examined on cement paste hydrated for 7 days. It was found that the carbonation appears either for samples smaller than 2.36 mm and bigger than 4.75 mm or samples soaked in a solvent for longer than 1 h. Fast solvent replacement leads to ettringite diminution and total pore volume increase. Among others, solvent replacement with subsequent gentle heating under a vacuum was found to be the most efficient, whereas it was experimentally demonstrated that isopropyl alcohol stops hydration faster than ethanol and acetone. KW - Hydration stoppage KW - Solvent replacement KW - Soaking time KW - Sample piece size PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582430 DO - https://doi.org/10.3390/su15021080 VL - 15 IS - 2 SP - 1 EP - 21 PB - MDPI CY - Basel, Switzerland. AN - OPUS4-58243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Patrick A1 - Schneider, Ronald A1 - Baeßler, Matthias A1 - Morgenthal, Guido ED - Cha, Young-Jin T1 - A Bayesian Probabilistic Framework for Building Models for Structural Health Monitoring of Structures Subject to Environmental Variability N2 - Managing aging engineering structures requires damage identification, capacity reassessment, and prediction of remaining service life. Data from structural health monitoring (SHM) systems can be utilized to detect and characterize potential damage. However, environmental and operational variations impair the identification of damages from SHM data. Motivated by this, we introduce a Bayesian probabilistic framework for building models and identifying damage in monitored structures subject to environmental variability. The novelty of our work lies (a) in explicitly considering the effect of environmental influences and potential structural damages in the modeling to enable more accurate damage identification and (b) in proposing a methodological workflow for model‐based structural health monitoring that leverages model class selection for model building and damage identification. The framework is applied to a progressively damaged reinforced concrete beam subject to temperature variations in a climate chamber. Based on deflections and inclinations measured during diagnostic load tests of the undamaged structure, the most appropriate modeling approach for describing the temperature‐dependent behavior of the undamaged beam is identified. In the damaged state, damage is characterized based on the identified model parameters. The location and extent of the identified damage are consistent with the cracks observed in the laboratory. A numerical study with synthetic data is used to validate the parameter identification. The known true parameters lie within the 90% highest density intervals of the posterior distributions of the model parameters, suggesting that this approach is reliable for parameter identification. Our results indicate that the proposed framework can answer the question of damage identification under environmental variations. These findings show a way forward in integrating SHM data into the management of infrastructures. KW - Verkehrsinfrastukturen KW - SHM KW - Model Updating KW - Environmental and Operational Variability KW - Damage Identification KW - Model Building PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605027 DO - https://doi.org/10.1155/2024/4204316 VL - 2024 IS - 1 SP - 1 EP - 23 PB - Wiley AN - OPUS4-60502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andrés Arcones, Daniel A1 - Weiser, M. A1 - Koutsourelakis, F. A1 - Unger, Jörg F. T1 - A Bayesian Framework for Simulation-based Digital Twins of Bridges N2 - Simulation-based digital twins have emerged as a powerful tool for evaluating the mechanical response of bridges. As virtual representations of physical systems, digital twins can provide a wealth of information that complements traditional inspection and monitoring data. By incorporating virtual sensors and predictive maintenance strategies, they have the potential to improve our understanding of the behavior and performance of bridges over time. However, as bridges age and undergo regular loading and extreme events, their tructural characteristics change, often differing from the predictions of their initial design. Digital twins must be continuously adapted to reflect these changes. In this article, we present a Bayesian framework for updating simulation-based digital twins in the context of bridges. Our approach integrates information from measurements to account for inaccuracies in the simulation model and quantify uncertainties. Through its implementation and assessment, this work demonstrates the potential for digital twins to provide a reliable and up-to-date representation of bridge behavior, helping to inform decision-making for maintenance and management. T2 - Eurostruct 2023 CY - Vienna, Austria DA - 25.09.2023 KW - Digital Twins KW - Bayesian Inference KW - Bridge Monitoring KW - Uncertainty Quantification PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586803 UR - https://eurostruct.org/eurostruct-2023/ DO - https://doi.org/10.1002/cepa.2177 SN - 2509-7075 VL - 6 IS - 5 SP - 734 EP - 740 PB - Ernst & Sohn CY - Berlin AN - OPUS4-58680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Monavari, M. A1 - Medhekar, R. A1 - Nawaz, Q. A1 - Monavari, Mehran A1 - Fuentes‐Chandía, M. A1 - Homaeigohar, S. A1 - Boccaccini, A. R. T1 - A 3D printed bone tissue engineering scaffold composed of alginate dialdehyde-gelatine reinforced by lysozyme loaded cerium doped mesoporous silica-calcia nanoparticles N2 - A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) is 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raise the mechanical stiffness of the hydrogel composite scaffold and induce surface apatite mineralization, when the scaffold is immersed in simulated body fluid (SBF). Moreover, the scaffolds can co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds can hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel bone tissue engineering (BTE) scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth. KW - Materials chemistry KW - Polymers and plastics KW - Biomaterials KW - Bioengineering KW - Biotechnology KW - 3D printing KW - Bone tissue engineering KW - Drug delivery KW - Lysozyme KW - Mesoporous SiO2-CaO nanoparticles PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581238 DO - https://doi.org/10.1002/mabi.202200113 SN - 1616-5195 VL - 22 IS - 9 SP - 1 EP - 15 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapa, Thomas A1 - Schreier, Andy A1 - Krebber, Katerina T1 - A 100-km BOFDA Assisted by First-Order Bi-Directional Raman Amplification N2 - We present, to our knowledge for the first time, a 100-km Brillouin Optical Frequency-Domain Analysis (BOFDA) employing a 200-km fiber loop. Compared to our previous publication, enhanced sensor length, sensor accuracy and spatial resolution are presented. The performance improvements are achieved by applying distributed Raman amplification (DRA) and a digital high-pass filter. We report on temperature measurements over sensing distances of 75 km and 100 km both with a 12.5-m spatial resolution. Temperature changes of 5 °C have been measured along 75 km sensing fiber. A temperature change of 30 °C has been detected at 99.5 km. KW - Distributed sensing KW - Fiber optics sensors KW - Stimulated Brillouin scattering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476577 DO - https://doi.org/10.3390/s19071527 SN - 1424-8220 VL - 19 IS - 7 SP - 1527, 1 EP - 9 PB - MDPI CY - Basel, Switzerland AN - OPUS4-47657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Serebrennikova, P. A1 - Komarov, V. A1 - Sukhikh, A. A1 - Khranenko, S. A1 - Zadesenetz, A. A1 - Gromilov, S A1 - Yusenko, Kirill T1 - [NiEn3](MoO4)0.5(WO4)0.5 co-crystals as single-source precursors for ternary refractory Ni-Mo-W alloys N2 - The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown. KW - Single source precursors KW - Phase diagrams PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540123 DO - https://doi.org/10.3390/nano11123272 VL - 11 IS - 12 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-54012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapa, Thomas A1 - Schreier, Andy A1 - Krebber, Katerina T1 - 63 km BOFDA for temperature and strain monitoring N2 - We demonstrate (and are the first to do so) 63 km Brillouin Optical Frequency-Domain Analysis (BOFDA) for temperature and strain monitoring using a 100 km fiber loop. The use of BOFDA for long-range applications can be considered a novel approach, as previous investigations focused on the utilization of Brillouin Optical Time-Domain Reflectometry and Analysis (BOTDR and BOTDA, respectively). At 51.7 km, a 100 m hotspot (37 °C) was detected without using distributed Raman amplification or image processing. KW - Distributed sensing KW - Stimulated Brillouin scattering KW - Fiber optics sensors PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449679 DO - https://doi.org/10.3390/s18051600 SN - 1424-8220 VL - 18 IS - 5 SP - 1600, 1 EP - 9 PB - MDPI CY - Basel, Switzerland AN - OPUS4-44967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Evsevleev, Sergei A1 - Serrano Munoz, Itziar A1 - Gollwitzer, Christian A1 - Bruno, Giovanni T1 - 3D shape analysis of powder for laser beam melting by synchrotron X-ray CT N2 - The quality of components made by laser beam melting (LBM) additive manufacturing is naturally influenced by the quality of the powder bed. A packing density <1 and porosity inside the powder particles lead to intrinsic voids in the powder bed. Since the packing density is determined by the particle size and shape distribution, the determination of these properties is of significant interest to assess the printing process. In this work, the size and shape distribution, the amount of the particle’s intrinsic porosity, as well as the packing density of micrometric powder used for LBM, have been investigated by means of synchrotron X-ray computed tomography (CT). Two different powder batches were investigated: Ti–6Al–4V produced by plasma atomization and stainless steel 316L produced by gas atomization. Plasma atomization particles were observed to be more spherical in terms of the mean anisotropy compared to particles produced by gas atomization. The two kinds of particles were comparable in size according to the equivalent diameter. The packing density was lower (i.e., the powder bed contained more voids in between particles) for the Ti–6Al–4V particles. The comparison of the tomographic results with laser diffraction, as another particle size measurement technique, proved to be in agreement. KW - Additive manufacturing KW - Laser beam melting KW - Synchrotron computed tomography KW - Powder analysis KW - Imaging PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474070 DO - https://doi.org/10.3390/qubs3010003 SN - 2412-382X VL - 3 IS - 1 SP - 3, 1 EP - 12 PB - MDPI AN - OPUS4-47407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rahrig, M. A1 - Torge, Manfred T1 - 3D inspection of the restoration and conservation of stained glass windows using high resolution structured light scanning N2 - The initial focus of this research was on the development of a general workflow for the documentation and monitoring of historical stained glass windows using structured light scanning. Therefore windows from different churches, time periods and with different corrosion and damage phenomena were scanned before and after conservation measures. To evaluate the execution of the restoration measures the data was compared using 3D inspection software to examine the differences in geometry between the two scans. Various problems had to be solved, for example, how to deal with heavily reflective surfaces and the extreme contrast between light and dark surfaces, as seen in the borders between ‘Schwarzlot’ painting and plain glass. The application of materials for matting the surfaces, such as Cyclododecane spray, was impossible due to the high accuracy of the surface measurement required for 3D inspection. Regarding the contrast differences of the surfaces, the creation of exposure fusions and the use of polarization filters to reduce reflections were tested. In addition to the general problems encountered when recording translucent surfaces, the historical glasses caused additional problems in calculating surface comparisons. For example, the windows have to be moved and turned around several times, both during the conservation process and while scanning, causing deformations of the geometry due to the flexible lead rods allowing a certain degree of movement. T2 - 27th CIPA International Symposium “Documenting the past for a better future” CY - Ávila, Spain DA - 01.09.2019 KW - Stained glass KW - Restoration and conservation KW - Structured light scanning KW - 3D inspection KW - Glass scanning PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491286 DO - https://doi.org/10.5194/isprs-archives-XLII-2-W15-965-2019 VL - XLII-2/W15 SP - 965 EP - 972 PB - International Society of Photogrammetry and Remote Sensing (ISPRS) CY - Hannover AN - OPUS4-49128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Schaupp, Thomas A1 - Müller, Bernd R. A1 - Griesche, Axel A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Kannengießer, Thomas A1 - Bruno, Giovanni T1 - 3D Crack analysis in hydrogen charged lean duplex stainless steel with synchrotron refraction CT N2 - Hydrogen in metals can cause a degradation of the mechanical properties, the so-called hydrogen embrittlement. In combination with internal stresses, hydrogen assisted cracking (HAC) can occur. This phenomenon is not completely understood yet. To better characterise the cracking behaviour, it is important to gain information about the evolution of the 3D crack network. For this purpose samples of lean duplex stainless steel were loaded with hydrogen by means of electrochemical charging and investigated by means of synchrotron refraction CT and SEM fractography after uniaxial tensile loading. Synchrotron refraction CT is an analyser-based imaging (ABI) technique. It uses a Si (111) single crystal as analyser, which is placed into the beam path between sample and detector. According to Bragg’s law only incident x-rays within a narrow range around the Bragg-angle are diffracted from the analyser into the detector. Hence, the analyser acts as an angular filter for the transmitted beam. This filtering allows to turn the refraction and scattering of x-rays into image contrast. Refraction occurs at all interfaces, where the density of the material changes and is more sensitive to density changes than the attenuation. Therefore, it is possible to detect smaller cracks than with classical x-ray imaging techniques, like CT, with comparable spacial resolution. It also visualises the 3D structure of the cracks and gains quantitative information about their morphology and distribution. Since cracks introduced by HAC are usually very small and have a small opening displacement, synchrotron refraction CT is expected to be well suited for imaging this cracking mechanism and can be a valuable tool to characterise the formation and the evolution of a 3D crack network. T2 - WCNDT 2016 CY - München, Germany DA - 13.06.2016 KW - X-ray refraction KW - Computed tomography KW - Hydrogen assisted cracking KW - Duplex stainless steel PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366481 SN - 978-3-940283-78-8 VL - BB 158 SP - Tu.4.B.3, 1 EP - 9 AN - OPUS4-36648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritsch, Tobias A1 - Farahbod-Sternahl, L. A1 - Serrano Munoz, Itziar A1 - Léonard, F. A1 - Haberland, C. A1 - Bruno, Giovanni T1 - 3D Computed Tomography Quantifies the Dependence of Bulk Porosity, Surface Roughness, and Re-Entrant Features on Build Angle in Additively Manufactured IN625 Lattice Struts N2 - Layer-by-layer additive manufacturing (AM) by means of laser-powder bed Fusion (L-PBF) offers many prospects regarding the design of lattice structures used, for example, in gas turbines. However, defects such as bulk porosity, Surface roughness, and re-entrant features are exacerbated in nonvertical structures, such as tilted struts. The characterization and quantification of these kinds of defects are essential for the correct estimation of fracture and fatigue properties. Herein, cylindrical struts fabricated by L-PBF are investigated by means of X-ray computed tomography (XCT), with the aim of casting light on the dependence of the three kinds of defects (bulk porosity, surface roughness, and re-entrant features) on the build angle. Innovative analysis methods are proposed to correlate shape and position of pores, to determine the angular-resolved Surface roughness, and to quantify the amount of re-entrant surface features, q. A meshing of the XCT surface enables the correlation of q with the classical Surface roughness Pa. This analysis leads to the conclusion that there is a linear correlation between q and Pa. However, it is conjectured that there must be a threshold of surface roughness, below which no re-entrant features can be build. KW - Additive manufacturing KW - Laser powder bed fusion KW - Computed tomography KW - Surface roughness analysis KW - Re-entrant surface feature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534728 DO - https://doi.org/10.1002/adem.202100689 IS - 2100689 SP - 1 EP - 8 PB - Wiley-VCH Verlag AN - OPUS4-53472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lay, Vera A1 - Buske, S. A1 - Townend, J. A1 - Kellett, R. A1 - Savage, M. A1 - Schmitt, D. R. A1 - Constantinou, A. A1 - Eccles, J. D. A1 - Gorman, A. A1 - Bertram, M. A1 - Hall, K. A1 - Lawton, D. A1 - Kofman, R. T1 - 3D Active Source Seismic Imaging of the Alpine Fault Zone and the Whataroa Glacial Valley in New Zealand N2 - The Alpine Fault zone in New Zealand marks a major transpressional plate boundary that is late in its typical earthquake cycle. Understanding the subsurface structures is crucial to understand the tectonic processes taking place. A unique seismic survey including 2D lines, a 3D array, and borehole recordings, has been performed in the Whataroa Valley and provides new insights into the Alpine Fault zone down to ∼2 km depth at the location of the Deep Fault Drilling Project (DFDP)-2 drill site. Seismic images are obtained by focusing prestack depth migration approaches. Despite the challenging conditions for seismic imaging within a sediment filled glacial valley and steeply dipping valley flanks, several structures related to the valley itself as well as the tectonic fault system are imaged. A set of several reflectors dipping 40°–56° to the southeast are identified in a ∼600 m wide zone that is interpreted to be the minimum extent of the damage zone. Different approaches image one distinct reflector dipping at ∼40°, which is interpreted to be the main Alpine Fault reflector located only ∼100 m beneath the maximum drilled depth of the DFDP-2B borehole. At shallower depths (z < 0.5 km), additional reflectors are identified as fault segments with generally steeper dips up to 56°. Additionally, a glacially over-deepened trough with nearly horizontally layered sediments and a major fault (z < 0.5 km) are identified 0.5–1 km south of the DFDP-2B borehole. Thus, a complex structural environment is seismically imaged and shows the complexity of the Alpine Fault at Whataroa. KW - Imaging KW - Signal processing KW - Seismic KW - Borehole KW - DAS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539163 DO - https://doi.org/10.1029/2021JB023013 VL - 126 IS - 12 SP - 1 EP - 21 PB - American Geophysical Union AN - OPUS4-53916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavasolyzadeh, Zeynab A1 - Tang, Peng A1 - Hahn, Marc Benjamin A1 - Hweidi, Gada A1 - Nordholt, Niclas A1 - Haag, Rainer A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential. KW - Direct laser writing KW - Mussel-inspired materials KW - Polyglycerol KW - Polydopamine KW - Micropatterning PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778 DO - https://doi.org/10.1002/smll.202309394 SN - 1613-6829 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Jäger, Christian T1 - 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel-zeolite composites N2 - The influence of starting materials and synthesis route on the properties and the structure of cementitious sodium aluminosilicate gels is not fully understood, partly due their amorphous nature and the fact that they often contain residual reactants, which can make the results of single-pulse NMR spectroscopy applied to these materials difficult to interpret or ambiguous. To overcome some of these limitations, 29Si{27Al} TRAPDOR NMR as well as 27Al{29Si} and 27Al{1H} REDOR NMR spectroscopy were applied to materials synthesized by the one-part alkali-activation route from three different amorphous silica starting materials, including rice husk ash. The latter led to formation of a fully amorphous sodium aluminosilicate gel (geopolymer), while the materials produced from the other silicas contained amorphous phase and crystalline zeolites. Application of the double-resonance NMR methods allowed to identify hydrous alumina gel domains in the rice husk ash-based material as well as significantly differing amounts of residual silica in the three cured materials. Four-coordinated Al existed not only in the aluminosilicate gel framework but also in a water-rich chemical environment with only a small amount of Si in proximity, likely in the alumina gel or possibly present as extra-framework Al in the aluminosilicate gel. The results demonstrate how the employment of different silica starting materials determines the phase assemblage of one-part alkali-activated materials, which in turn influences their engineering properties such as the resistance against chemically/biologically aggressive media. KW - Alkali-activated materials KW - Solid-state NMR KW - Aluminium hydroxide KW - Rice husk ash PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469353 DO - https://doi.org/10.1039/C8RA09246J SN - 2046-2069 VL - 8 IS - 70 SP - 40164 EP - 40171 PB - Royal Society of Chemistry AN - OPUS4-46935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jablonka, Kevin Maik A1 - Ai, Qianxiang A1 - Al-Feghali, Alexander A1 - Badhwar, Shruti A1 - Bocarsly, Joshua D. A1 - Bran, Andres M. A1 - Bringuier, Stefan A1 - Brinson, L. Catherine A1 - Choudhary, Kamal A1 - Circi, Defne A1 - Cox, Sam A1 - de Jong, Wibe A. A1 - Evans, Matthew L. A1 - Gastellu, Nicolas A1 - Genzling, Jerome A1 - Gil, María Victoria A1 - Gupta, Ankur K. A1 - Hong, Zhi A1 - Imran, Alishba A1 - Kruschwitz, Sabine A1 - Labarre, Anne A1 - Lála, Jakub A1 - Liu, Tao A1 - Ma, Steven A1 - Majumdar, Sauradeep A1 - Merz, Garrett W. A1 - Moitessier, Nicolas A1 - Moubarak, Elias A1 - Mouriño, Beatriz A1 - Pelkie, Brenden A1 - Pieler, Michael A1 - Ramos, Mayk Caldas A1 - Ranković, Bojana A1 - Rodriques, Samuel G. A1 - Sanders, Jacob N. A1 - Schwaller, Philippe A1 - Schwarting, Marcus A1 - Shi, Jiale A1 - Smit, Berend A1 - Smith, Ben E. A1 - Van Herck, Joren A1 - Völker, Christoph A1 - Ward, Logan A1 - Warren, Sean A1 - Weiser, Benjamin A1 - Zhang, Sylvester A1 - Zhang, Xiaoqi A1 - Zia, Ghezal Ahmad A1 - Scourtas, Aristana A1 - Schmidt, K. J. A1 - Foster, Ian A1 - White, Andrew D. A1 - Blaiszik, Ben T1 - 14 examples of how LLMs can transform materials science and chemistry: a reflection on a large language model hackathon N2 - Large-language models (LLMs) such as GPT-4 caught the interest of many scientists. Recent studies suggested that these models could be useful in chemistry and materials science. To explore these possibilities, we organized a hackathon. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines. KW - Large Language model KW - Hackathon KW - Concrete KW - Prediction KW - Inverse Design KW - Orchestration PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589961 DO - https://doi.org/10.1039/d3dd00113j VL - 2 IS - 5 SP - 1233 EP - 1250 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuhlich, Paul A1 - Emmerling, Franziska A1 - Kraus, Werner A1 - Nehls, Irene A1 - Piechotta, Christian T1 - 1-(4-bromo-3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)ethan-1-one: a precursor for phase-I metabolite of AHTN N2 - The title compound, C18H25BrO, crystallized as a racemate with four independent molecules in the asymmetric unit. In the crystal, three of these four molecules are linked via C-Br...Br-C halogen bonds [Br...Br = 3.662 (2) and 3.652 (2) Å], forming dimers. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-279935 DO - https://doi.org/10.1107/S1600536813006934 SN - 1600-5368 VL - 69 IS - 4 SP - o545, sup-1 EP - sup-17 PB - Munksgaard CY - Copenhagen AN - OPUS4-27993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knigge, Xenia A1 - Radnik, Jörg T1 - 1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES N2 - The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy. Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown. KW - C7H15N2O4P KW - [MMIM]+[DMP]− KW - Lonic liquid KW - Hard x-ray photoelectron spectroscopy KW - HAXPES KW - XPS PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571604 DO - https://doi.org/10.1116/6.0002297 VL - 30 IS - 1 SP - 1 EP - 20 PB - AIP Publishing AN - OPUS4-57160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -