TY - CONF A1 - Kern, Simon A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich A1 - King, R. A1 - Maiwald, Michael ED - Herwig, Christoph T1 - “Click” analytics for “click” chemistry – a simple method for calibration-free evaluation of online NMR spectra N2 - Currently, research in chemical manufacturing moves towards flexible plug-and-play approaches focusing on modular plants, capable of producing small scales on-demand with short down-times between individual campaigns. This approach allows for efficient use of hardware, a faster optimization of the process conditions, and thus, an accelerated introduction of new products to the market. Driven mostly by the search for chemical syntheses under biocompatible conditions, so-called “click” chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques. Here we report on a fast and reliable calibration-free online high field NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement with a time interval of 20 s per spectrum, and a robust, automated algorithm to interpret the obtained data. All spectra were acquired using a 500 MHz NMR spectrometer (Varian) with a dual band flow probe having a 1/16-inch polymer tubing working as a flow cell. Single scan 1H NMR spectra were recorded with an acquisition time of 5 s, relaxation delay of 15 s. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in non-deuterated solvents while its time-resolved behaviour was characterised with step tracer experiments. Through the application of spectral modeling the signal area for each reactant can be deconvoluted in the online spectra and thus converted to the respective concentrations or molar ratios. The signals which were suitable for direct integration were used herein for comparison purposes of both methods. T2 - 11. Interdisziplinäres Doktorandenseminar CY - Berlin, Germany DA - 12.03.2017 KW - Process Monitoring KW - Online NMR Spectroscopy KW - Indirect Hard Modeling KW - Process Control KW - Process Analytical Technology KW - CONSENS KW - Click Chemistry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435531 SP - 33 EP - 35 PB - Gesellschaft Deutscher Chemiker (GDCh) CY - Frankfurt a. M. AN - OPUS4-43553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Michalik-Onichimowska, Aleksandra A1 - Kern, Simon A1 - Riedel, Jens A1 - Panne, Ulrich A1 - King, R. A1 - Maiwald, Michael T1 - ‘‘Click” analytics for ‘‘click” chemistry – A simple method for calibration–free evaluation of online NMR spectra N2 - Driven mostly by the search for chemical syntheses under biocompatible conditions, so called "click" chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of 1H spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibrationfree approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h-1 at 25 °C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance. KW - Online NMR Spectroscopy KW - Reaction Monitoring KW - Automated Data Evaluation KW - Thiol-ene click chemistry KW - Click Chemistry KW - Process Analytical Technology PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393232 UR - http://www.sciencedirect.com/science/article/pii/S1090780717300575 DO - https://doi.org/10.1016/j.jmr.2017.02.018 VL - 277 SP - 154 EP - 161 PB - Elsevier Inc. CY - Oxford AN - OPUS4-39323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vo, P. H.N. A1 - Vogel, Christian A1 - Nguyen, H. T.M. A1 - Hamilton, B. R. A1 - Thai, P. K. A1 - Roesch, Philipp A1 - Simon, Franz-Georg A1 - Mueller, J. F. T1 - µ-X-ray fluorescence (XRF) and fluorine K-edge µ-X-ray absorption near-edge structure (XANES) spectroscopy for detection of PFAS distribution in the impacted concrete N2 - An improved understanding of the distribution of per- and polyfluoroalkyl substances (PFAS) in PFAS-impacted concrete is important for risk management and decontamination of PFAS. This study incorporates µ-X-ray fluorescence (µ-XRF) and fluorine K-edge µ-X-ray absorption near-edge structure (µ-XANES) spectroscopy to gain non-destructive insights into PFAS distribution in the impacted concrete. The μ-XRF and μ-XANES spectroscopy provided additional details on the detection of PFAS, which were not detected by the desorption electrospray ionization (DESI) imaging method conducted previously. The shorter chain PFAS were found on the top part of the concrete core (0.5 cm), and longer chain PFAS were mostly at the bottom part of the concrete core (5 cm). The inorganic fluorine fraction was also detected, and it likely hampered the detection of organic fluorine such as PFAS in the concrete. Thus, this non-destructive technique is an complementary approach to detect PFAS in contaminated concrete. KW - Beton KW - Per- and Polyfluoroalkyl substances (PFAS) KW - XANES spectroscopy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616711 DO - https://doi.org/10.1016/j.hazl.2024.100134 SN - 2666-9110 VL - 5 SP - 1 EP - 5 PB - Elsevier B.V. AN - OPUS4-61671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen T1 - Zwitterionic polymerization of glycolide catalyzed by pyridine N2 - The usefulness of various N- and P-based catalysts for syntheses of cyclic polyglycolide via zwitterionic polymerization of glycolide was examined. Most catalysts produced discolored, largely insoluble polyglycolides consisting of cycles and unidentified byproducts. Soluble, cyclic polyglycolides were obtained using neat pyridine as catalyst at 120 °C, 100 °C, 80 °C, and even at 60 °C. The number-average molecular weights were extremely low and depended slightly on the glycolide-to-pyridine ratio. Three different mass distributions of the cycles were detected by mass spectrometry, depending on the reaction conditions. The cyclic polyglycolides were also characterized by differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) measurements. The SAXS data in combination with the mass spectra indicate that the majority of the cycles form extended-ring crystallites KW - MALDI-TOF MS KW - Polylactide KW - Polymerization KW - Zitterions PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639748 DO - https://doi.org/10.1039/d5py00762c SN - 1759-9954 SP - 1 EP - 9 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63974 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinekamp, Christian A1 - Roy, Arkendu A1 - Karafiludis, Stephanos A1 - Kumar, Sourabh A1 - de Oliveira Guilherme Buzanich, Ana A1 - Stawski, Tomasz M. A1 - Miliūtė, Aistė A1 - von der Au, Marcus A1 - Ahrens, Mike A1 - Braun, Thomas A1 - Emmerling, Franziska T1 - Zirconium fluoride-supported high-entropy fluoride: a catalyst for enhanced oxygen evolution reaction N2 - Extended hydrogen initiatives promote the urgency of research on water splitting technologies and, therein, oxygen evolution reaction catalysts being developed. A route to access a ZrF4 supported high-entropy fluoride catalyst using a facile sol–gel route is presented. The high-entropy character of the catalyst was confirmed by scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (STEM-EDX) as well as inductively coupled plasma-mass spectrometry (ICP-MS). Additional investigations on the local structure were performed using extended X-ray absorption fine structure spectroscopy (EXAFS) and pair distribution function (PDF) analysis. The catalyst shows significant potential for oxygen evolution reaction (OER) in alkaline media with a current density of 100 mA cm−2 at approximately 1.60 V, thus outperforming benchmark materials such as IrO2, despite a significant reduction in electrochemical mass loading. A potential mechanism is suggested based on free energy calculation using DFT calculations. KW - OER KW - HEA KW - CCMAT PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637116 DO - https://doi.org/10.1039/D4TA08664C SN - 2050-7488 VL - 13 IS - 26 SP - 20383 EP - 20393 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Smales, Glen Jacob A1 - Clark, Adam H. A1 - Thünemann, Andreas T1 - Zinc Phosphate Nanoparticles Produced in Saliva N2 - This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization. KW - SAXS KW - Digestion KW - Zinc phosphate PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514239 DO - https://doi.org/10.1002/ejic.202000521 IS - 38 SP - 3654 EP - 3661 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-51423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balderas-Xicohtencatl, R. A1 - Villajos Collado, José Antonio A1 - Casabán, J. A1 - Wong, D. A1 - Maiwald, Michael A1 - Hirscher, M. T1 - ZIF‑8 Pellets as a Robust Material for Hydrogen Cryo-Adsorption Tanks N2 - Cryoadsorption on the inner surface of porous materials is a promising solution for safe, fast, and reversible hydrogen storage. Within the class of highly porous metal−organic frameworks, zeolitic imidazolate frameworks (ZIFs) show high thermal, chemical, and mechanical stability. In this study, we selected ZIF-8 synthesized mechanochemically by twin-screw extrusion as powder and pellets. The hydrogen storage capacity at 77 K and up to 100 bar has been analyzed in two laboratories applying three different measurement setups showing a high reproducibility. Pelletizing ZIF-8 increases the packing density close to the corresponding value for a single crystal without loss of porosity, resulting in an improved volumetric hydrogen storage capacity close to the upper limit for a single crystal. The high volumetric uptake combined with a low and constant heat of adsorption provides ca. 31 g of usable hydrogen per liter of pellet assuming a temperature−pressure swing adsorption process between 77 K − 100 bar and 117 K − 5 bar. Cycling experiments do not indicate any degradation in storage capacity. The excellent stability during preparation, handling, and operation of ZIF-8 pellets demonstrates its potential as a robust adsorbent material for technical application in pilot- and full-scale adsorption vessel prototypes. KW - Hydrogen adsorption storage KW - Metal−organic frameworks KW - ZIF-8 KW - Cryoadsorption KW - Hydrogen Storage KW - MefHySto PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569473 DO - https://doi.org/10.1021/acsaem.2c03719 SN - 2574-0962 SP - 1 EP - 8 PB - ACS Publications CY - Washington DC AN - OPUS4-56947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gugin, Nikita A1 - Schwab, Alexander A1 - Carraro, Francesco A1 - Tavernaro, Isabella A1 - Falkenhagen, Jana A1 - Villajos, Jose A1 - Falcaro, Paolo A1 - Emmerling, Franziska T1 - ZIF-8-based biocomposites via reactive extrusion: towards industrial-scale manufacturing N2 - Mechanochemistry, a sustainable synthetic method that minimizes solvent use, has shown great promise in producing metal–organic framework (MOF)-based biocomposites through ball milling. While ball milling offers fast reaction times, biocompatible conditions, and access to previously unattainable biocomposites, it is a batch-type process typically limited to gram-scale production, which is insufficient to meet commercial capacity. We introduce a scalable approach for the continuous solid-state production of MOF-based biocomposites. Our study commences with model batch reactions to examine the encapsulation of various biomolecules into Zeolitic Imidazolate Framework-8 (ZIF-8) via hand mixing, establishing a foundation for upscaling. Subsequently, the process is scaled up using reactive extrusion, enabling continuous and reproducible kilogram-scale production of bovine serum albumin (BSA)@ZIF-8 with tunable protein loading. Furthermore, we achieve the one-step formation of shaped ZIF-8 extrudates encapsulating clinical therapeutic hyaluronic acid (HA). Upon release of HA from the composite, the molecular weight of HA is preserved, highlighting the industrial potential of reactive extrusion for the cost-effective and reliable manufacturing of biocomposites for drug-delivery applications. KW - Mechanochemistry KW - Extrusion KW - Biocompoites KW - MOFs PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654777 DO - https://doi.org/10.1039/D5TA08276E SN - 2050-7496 SP - 1 EP - 14 PB - Royal Society of Chemistry AN - OPUS4-65477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braymer, Joseph J. A1 - Knauer, Lukas A1 - Crack, Jason C. A1 - Oltmanns, Jonathan A1 - Heghmanns, Melanie A1 - Soares, Jéssica C. A1 - Le Brun, Nick E. A1 - Schünemann, Volker A1 - Kasanmascheff, Müge T1 - Yeast [FeFe]-hydrogenase-like protein Nar1 binds a [2Fe–2S] cluster N2 - Nar1 is an essential eukaryotic protein proposed to function as an iron–sulphur (Fe/S) cluster trafficking factor in the cytosolic iron–sulphur protein assembly (CIA) machinery. However, such a role has remained unclear due to difficulties in purifying adequate amounts of cofactor-bound protein. The [FeFe]-hydrogenase-like protein has two conserved binding sites for [4Fe–4S] clusters but does not show hydrogenase activity in vivo due to the lack of an active site [2Fe]H cofactor. Here, we report a new preparation procedure for Nar1 that facilitated studies by UV-vis, EPR, and Mössbauer spectroscopies, along with native mass spectrometry. Nar1 recombinantly produced in E. coli contained a [4Fe–4S] cluster, bound presumably at site 1, along with an unexpected [2Fe–2S] cluster bound at an unknown site. Fe/S reconstitution reactions installed a second [4Fe–4S] cluster at site 2, leading to protein with up to three Fe/S cofactors. It is proposed that the [2Fe–2S] cluster occupies a cavity in Nar1 that is filled by the [2Fe]H cofactor in [FeFe]-hydrogenases. Strikingly, two of the Fe/S clusters were rapidly destroyed by molecular oxygen, linking Nar1 oxygen sensitivity in vitro to phenotypes observed previously in vivo. Our biochemical results, therefore, validate a direct link between cellular oxygen concentrations and the functioning of the CIA pathway. These advances also now allow for the pursuit of in vitro Fe/S cluster transfer assays, which will shed light on Fe/S trafficking and insertion by CIA components. KW - Biocorrosion KW - Hydrogenases KW - Metalloprotein KW - Yeast PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649463 DO - https://doi.org/10.1039/D5SC04860E SN - 2041-6520 VL - 17 IS - 1 SP - 373 EP - 380 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Würth, Christian A1 - Grauel, Bettina A1 - Pons, Monika A1 - Frenzel, Florian A1 - Rissiek, P. A1 - Rücker, Kerstin A1 - Haase, Markus A1 - Resch-Genger, Ute T1 - Yb- and Er concentration dependence of the upconversion luminescence of highly doped NaYF4:Yb,Er/NaYF4:Lu core/shell nanocrystals prepared by a water-free synthesis N2 - High sensitizer and activator concentrations have been increasingly examined to improve the performance of multi-color emissive upconversion (UC) nanocrystals (UCNC) like NaYF4:Yb,Er and first strategies were reported to reduce concentration quenching in highly doped UCNC. UC luminescence (UCL) is, however, controlled not only by dopant concentration, yet by an interplay of different parameters including size, crystal and shell quality, and excitation power density (P). Thus, identifying optimum dopant concentrations requires systematic studies of UCNC designed to minimize additional quenching pathways and quantitative spectroscopy. Here, we quantify the dopant concentration dependence of the UCL quantum yield (ΦUC) of solid NaYF4:Yb,Er/NaYF4:Lu upconversion core/shell nanocrystals of varying Yb3+ and Er3+ concentrations (Yb3+ series: 20%‒98% Yb3+; 2% Er3+; Er3+ series: 60% Yb3+; 2%‒40% Er3+). To circumvent other luminescence quenching processes, an elaborate synthesis yielding OH-free UCNC with record ΦUC of ~9% and ~25 nm core particles with a thick surface shell were used. High Yb3+ concentrations barely reduce ΦUC from ~9% (20% Yb3+) to ~7% (98% Yb3+) for an Er3+ concentration of 2%, thereby allowing to strongly increase the particle absorption cross section and UCNC brightness. Although an increased Er3+ concentration reduces ΦUC from ~7% (2% Er3+) to 1% (40%) for 60% Yb3+. Nevertheless, at very high P (> 1 MW/cm2) used for microscopic studies, highly Er3+-doped UCNC display a high brightness because of reduced saturation. These findings underline the importance of synthesis control and will pave the road to many fundamental studies of UC materials. KW - Upconverion KW - Nanoparticle KW - Lanthanides KW - Quantum yield PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551346 DO - https://doi.org/10.1007/s12274-022-4570-5 SP - 1 EP - 8 PB - Springer AN - OPUS4-55134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraft, Sebastian A1 - Schille, J. A1 - Bonse, Jörn A1 - Löschner, U. A1 - Krüger, Jörg T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet. Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays. KW - Ultrashort pulsed laser KW - Laser-induced X-ray emission KW - Ophthalmology KW - Dentistry KW - Secondary hazard PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960 DO - https://doi.org/10.1007/s00339-023-06440-4 SN - 0947-8396 VL - 129 IS - 3 SP - 1 EP - 8 PB - Springer AN - OPUS4-56996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chemello, Giovanni A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - XPS–SEM/EDS Tandem Analysis for the Elemental Composition of Functionalized Graphene Nanoplatelets N2 - Over the past decade, energy-dispersive X-ray spectrometry (EDS) with scanning electron microscopy (SEM) has advanced to enable the accurate analysis of light elements such as C, N, or O. For this reason, EDS is becoming increasingly interesting as an analytical method for the elemental analysis of functionalized graphene and could be an attractive alternative to Xray photoelectron spectroscopy (XPS), which is considered the most important method for elemental analysis. In this study, comparative XPS and EDS investigations under different excitation conditions are carried out on commercially available powders containing graphene particles with different morphologies. The slightly different XPS/HAXPES and EDS results can be explained by the different information depths of the methods and the functionalization of the particle surfaces. For the material with smaller graphene particles and higher O/C ratios, all methods reported a lower O/C ratio in pellets compared with the unpressed powder samples. This clearly shows that sample preparation has a significant influence on the quantification results, especially for such a type of morphology. Overall, the study demonstrates that EDS is a reliable and fast alternative to XPS for the elemental quantification of functionalized graphene particles, provided that differences in the information depth are taken into account. Particle morphology can be examined in parallel with quantitative element analysis, since EDS spectrometers are typically coupled with SEM, which are available in a huge number of analytical laboratories. KW - Graphene oxide KW - SEM/EDS KW - XPS/HAXPES KW - Elemental composition KW - Functionalization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647294 DO - https://doi.org/10.1021/acsomega.5c07830 SN - 2470-1343 SP - 1 EP - 7 PB - American Chemical Society (ACS) AN - OPUS4-64729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Dietrich, P. A1 - Thissen, A. A1 - Kulak, N. A1 - Kjaervik, Marit A1 - Unger, Wolfgang T1 - XPS surface chemical analysis of aqueous solutions with EnviroESCA N2 - Water and aqueous reagents are essential in any biological process or system. But apart from a few special low vapor-pressure cases, liquids have not been accessible to any technique requiring UHV conditions. EnviroESCA opens up this exciting field of applications. In this paper first results from water based samples are presented as a proof of concept to demonstrate the special capabilities of EnviroESCA analyzing liquid samples. The following solutions were investigated under near ambient pressure conditions: i.) water, ii.) brine, iii.) an oil in water dispersion, iv.) aqueous iron(II) sulfate heptahydrate, and v.) a suspension of nano silver particles in water. KW - Surface Analysis KW - Near Ambient Pressure XPS KW - Aqueous Solutions PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394603 UR - http://www.enviro.specs.de/cms/upload/bilder/EnviroESCA/Applications/Liquids/Application-Note_EnviroESCA_Aqueous_Solutions.pdf N1 - BAM Mitarbeiter Beitrag im Acknowledgement definiert. IS - #000394 SP - 1 PB - SPECS CY - Berlin AN - OPUS4-39460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beygi Narsabadi, Hossein A1 - Vafaeenezhad, H. A1 - Klotz, U.E. A1 - Tiberto, D. A1 - Hosseinabadi, F. A1 - Mishurova, Tatiana A1 - Bruno, Giovanni A1 - Skrotzki, Birgit T1 - XCT-assisted micromechanical modeling of the effect of pores on the plastic deformation and mechanical characteristics of PBF-LB/M-produced copper alloys N2 - Due to the low absorption of fiber laser by copper particles, the laser-based powder bed fusion (PBF-LB/M) processing of copper components is accompanied by the development of different types of porosities within the printed samples. This research aims to assess the consequences of various process-induced pores on the me chanical characteristics and deformation of PBF-LB/M-produced copper alloys. Several copper alloys were processed using metal-coated particles and varied laser intensities, yielding samples with different types and amounts of porosities. For instance, CuCrZr alloys processed at 325 J/mm³ and 257 J/mm³ had 0.009 % and 1.117 % porosities, dominated by keyhole and lack-of-fusion pores, respectively. Moreover, PBF-LB/M pro cessing of Cr- and Nb-coated CuNi3SiCr particles accompanied by the generation of 0.004 % and 1.861 % porosities within the samples, predominantly featuring metallurgical and oxidation pores, respectively. Compression and nanoindentation tests revealed that the CuNi3SiCr alloy exhibited superior mechanical properties compared to the CuCrZr sample (nanoindentation hardness values 2.2 GPa and 1.4 GPa, respectively), while the presence of lack-of-fusion pores notably diminished their mechanical performance. X-ray computed tomography (XCT) reconstruction slices and scanning electron microscopy (SEM) images were then used for developing the representative volume elements (RVEs) based micromechanical models. The micromechanical simulations established a structure-property correlation that can simulate the compressive deformation and mechanical characteristics of PBF-LB/M-produced copper alloys as a function of their incorporated pore characteristics. Due to the closure of the pores at the first stages of deformation, samples with minimal keyhole and metallurgical porosities exhibited homogeneous plastic deformation. On the other side, based on the JohnsonCook model, strain concentration and crack propagation around the lack-of-fusion pores lead to damage initi ation in the printed samples at a strain level of 5 % KW - X-ray Computed tomography KW - Defects KW - Copper alloys KW - PBF-LB/M KW - Micromechanics PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624004 DO - https://doi.org/10.1016/j.msea.2025.147836 SN - 0921-5093 VL - 924 PB - Elsevier B.V. AN - OPUS4-62400 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Jaenisch, Gerd-Rüdiger A1 - Pavasaryte, Lina A1 - Funk, Alexander T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed. KW - Non-destructive testing KW - Two-photon polymerization KW - X-ray microscopy KW - XCT KW - 2PP KW - Direct laser writing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525 DO - https://doi.org/10.3390/app122010488 VL - 12 IS - 20 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-56052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tammas-Williams, S. A1 - Zhao, H. A1 - Léonard, Fabien A1 - Derguti, F. A1 - Todd, I. A1 - Prangnell, P.B. T1 - XCT analysis of the influence of melt strategies on defect population in Ti-6Al-4V components manufactured by Selective Electron Beam Melting N2 - Selective Electron Beam Melting (SEBM) is a promising powder bed Additive Manufacturing technique for near-net-shape manufacture of high-value titanium components. However without post-manufacture HIPing the fatigue life of SEBM parts is currently dominated by the presence of porosity. In this study, the size, volume fraction, and spatial distribution of the pores in model samples have been characterised in 3D, using X-ray Computed Tomography, and correlated to the process variables. The average volume fraction of the pores (b0.2%) was measured to be lower than that usually observed in competing processes, such as selective laser melting, but a strong relationship was found with the differentbeamstrategies used to contour ,and infill by hatching, a part section. The majority of pores were found to be small spherical gas pores, concentrated in the infill hatched region; this was attributed to the lower energy density and less focused beam used in the infill strategy allowing less opportunity for gas bubbles to escape the melt pool. Overall, increasing the energy density or focus of the beam was found to correlate strongly to a reduction in the level of gas porosity. Rarer irregular shaped pores were mostly located in the contour region and have been attributed to a lack of fusion between powder particles. KW - Titanium KW - Additive Manufacture KW - Selective Electron Beam Melting KW - Pores KW - X-ray computed tomography PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-416577 UR - http://www.sciencedirect.com/science/article/pii/S104458031500039X?via%3Dihub DO - https://doi.org/10.1016/j.matchar.2015.02.008 VL - 102 SP - 47 EP - 61 CY - Materials Characterization AN - OPUS4-41657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Nava, E. A1 - Tammas-Williams, S. A1 - Smith, C. A1 - Léonard, Fabien A1 - Withers, P. J. A1 - Todd, I. A1 - Goodall, R. T1 - X-ray tomography characterisation of lattice structures processed by selective electron beam melting N2 - Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 x 10⁻³ vol %) levels of pores, as do nodes at which many (in our case 24) struts meet. On the other hand, for struts more closely aligned (0° to 54°) to the build direction, the fraction of porosity appears to be much lower (~0.17 x 10⁻³%) arising mainly from pores contained within the original atomised powder particles. KW - Cellular solids KW - Aqdditive manufacturing KW - Computed tomography KW - Titanium alloys PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413689 UR - http://www.mdpi.com/2075-4701/7/8/300 DO - https://doi.org/10.3390/met7080300 SN - 2075-4701 VL - 7 IS - 8 SP - Article 300, 1 EP - 12 PB - MDPI AN - OPUS4-41368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kasperovich, G. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - X-ray refraction distinguishes unprocessed powder from empty pores in selective laser melting Ti-6Al-4V N2 - For the first time, X-ray refraction techniques are proven for the identification of void formation in Ti-6Al-4V parts produced by selective laser melting. The topology and volume fraction of pores are measured in samples produced with different laser energy density. Unique X-ray refraction methods identify different kinds of defects, characteristic to the regions below and above the Optimum laser energy density, namely unprocessed powder (unmolten powder particles, balling effect, and Fusion defects) from empty keyhole pores. Furthermore, it is possible to detect small inhomogeneities (voids or cracks) with sizes below the spatial resolution of optical microscopy and X-ray computed tomography. KW - Additive manufacturing KW - X-ray refraction KW - Microscopy KW - X-ray computed tomography KW - Porosity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434041 DO - https://doi.org/10.1080/21663831.2017.1409288 SN - 2166-3831 VL - 6 IS - 2 SP - 130 EP - 135 PB - Taylor & Francis Group CY - London, UK AN - OPUS4-43404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray radiation protection aspects during ultrashort laser processing N2 - Ultrashort pulse laser processing of materials allows for precise machining with high accuracy. By increasing the repetition rate to several 100 kHz, laser machining becomes quick and cost-effective. Ultrafast laser processing at high repetition rates and peak intensities above 10^13 W/cm^2 can cause a potential hazard by generation of unwanted x-ray radiation. Therefore, radiation protection must be considered. For 925 fs pulse duration at a center wavelength of 1030 nm, the x-ray emission in air at a repetition rate of 400 kHz was investigated up to a peak intensity of 2.6 × 10^14 W/cm^2. Based on the presented measurements, the properties of potential shielding materials will be discussed. By extending our previous works, a scaling of the x-ray radiation emission to higher peak intensities up to 10^15 W/cm^2 is described, and emitted x-ray doses are predicted. KW - Laser ablation KW - Ultrashort pulse laser processing KW - Laser-induced x-ray emission KW - Radiation protection PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505677 DO - https://doi.org/10.2351/1.5134778 VL - 32 IS - 2 SP - 022004 AN - OPUS4-50567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Trappe, Volker A1 - Nielow, D. A1 - Schumacher, David A1 - Lange, A. A1 - Hentschel, M.P. A1 - Redmer, Bernhard A1 - Ewert, U. A1 - Bruno, Giovanni T1 - X-ray laminographic inspection of sandwich shell segments for wind turbine rotor blades N2 - 3D structural investigations are described by X-ray laminography studies of sandwich shell segments, made of a PVC foam core, covered by non-crimp fabric glass fibre composite lay-ups processed by vacuum assisted resin infusion of epoxy. The specific scope of this study is to image transversal flaws within the foam core (joints) and of single ply overlaps. Test flaws were purposely implemented in order to simulate typical failure under cyclic load. In a dedicated test rig for shell structures, the flaw evolution/propagation is monitored by thermography and optical 3D inspection of deformation. Due to the unfavourable preconditions for classical computed tomography as of large aspect ratio, the samples were investigated by coplanar translational laminography. Its limited range of observation angles of ± 45°, results in anisotropic artefacts about the normal to the sample surface, but the typical flaws are well visualized in the as-prepared state, in a state of early damage, and in the repaired state. T2 - 12th European conference on Non-Destructive Testing CY - Gothenburg, Sweden DA - 11.06.2018 KW - X-ray laminography KW - Wind turbine KW - Rotor blade PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453931 SN - 978-91-639-6217-2 SP - 1 EP - 8 AN - OPUS4-45393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stolzenberg, U. A1 - Schmitt Rahner, M. A1 - Pullner, B. A1 - Legall, Herbert A1 - Bonse, Jörn A1 - Kluge, M. A1 - Ortner, A. A1 - Hoppe, B. A1 - Krüger, Jörg T1 - X-ray emission hazards from ultrashort pulsed laser material processing in an industrial setting N2 - Interactions between ultrashort laser pulses with intensities larger than 10^13 W/cm^2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 10^15 W/cm^2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified. KW - X-ray emission hazards KW - Ultrashort pulsed laser KW - Radiation protection KW - Industrial applications KW - Protection housing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538632 DO - https://doi.org/10.3390/ma14237163 SN - 1996-1944 VL - 14 SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-53863 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Pentzien, Simone A1 - Dittmar, G. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission as a potential hazard during ultrashort pulse laser material processing N2 - In laser machining with ultrashort laser pulses unwanted X-ray radiation in the keV range can be generated when a critical laser intensity is exceeded. Even if the emitted X-ray dose per pulse is low, high laser repetition rates can lead to an accumulation of X-ray doses beyond exposure safety limits. For 925 fs pulse duration at a center wavelength of 1030 nm, the X-ray emission was investigated up to an intensity of 2.6 × 10^14 W/cm2. The experiments were performed in air with a thin disk laser at a repetition rate of 400 kHz. X-ray spectra and doses were measured for various planar target materials covering a wide range of the periodic table from aluminum to tungsten. Without radiation shielding, the measured radiation doses at this high repetition rate clearly exceed the regulatory limits. Estimations for an adequate radiation shielding are provided. KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Femtosecond laser KW - Radiation protection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448431 DO - https://doi.org/10.1007/s00339-018-1828-6 SN - 0947-8396 SN - 1432-0630 VL - 124 IS - 6 SP - Article 407, 1 EP - 8 PB - Springer AN - OPUS4-44843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröder, Jakob A1 - Han, Ying A1 - Fritsch, Tobias A1 - Hejazi, Bardia A1 - Ulbricht, Alexander A1 - Skrotzki, Birgit A1 - Bruno, Giovanni T1 - X-ray computed tomography quantifies primary phases and reveals crack morphology in high-cycle fatigue of aluminum alloy EN AW-2618A N2 - Since the introduction of high-strength aluminum alloys understanding their fatigue behavior is of high interest for the structural integrity of engineering components, in this context, the alloy EN AW-2618A gains its high strength from both nanometer size precipitates and micrometer size primary phases. The latter phases are often identified as crack initiation sites. In this study, it uses a combination of synchrotron and laboratory-based X-ray computed tomography to image and quantify such primary phases and the fatigue cracks appearing in interrupted tests. Based on the gray-level differences in the synchrotron X-ray computed tomography scans, this study is able to distinguish low- and high-absorbing particles. The dominant (volume fraction >99%) high absorbing primary phase can be quantified in good agreement with results of Thermo-Calc calculations. To image the fatigue crack, laboratory X-ray computed tomography scans are performed at different tensile loads to open the crack. The results show that with an appropriate crack opening tensile load, the fatigue crack morphology can be reliably revealed. Based on these results, the influence of the primary phases on the fatigue crack initiation and propagation are discussed. KW - X-ray computed tomography KW - Fatigue KW - Aluminum KW - Primary phases PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632724 DO - https://doi.org/10.1002/adem.202500235 SN - 1527-2648 SP - 1 EP - 9 PB - Wiley-VCH CY - Weinheim AN - OPUS4-63272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Evsevleev, Sergei A1 - Mishurova, Tatiana A1 - Khrapov, D. A1 - Paveleva, A. A1 - Meinel, Dietmar A1 - Surmenev, R. A1 - Surmeneva, M. A1 - Koptyug, A. A1 - Bruno, Giovanni T1 - X-ray Computed Tomography Procedures to Quantitatively Characterize the Morphological Features of Triply Periodic Minimal Surface Structures N2 - Additively manufactured (AM) metallic sheet-based Triply Periodic Minimal Surface Structures (TPMSS) meet several requirements in both bio-medical and engineering fields: Tunable mechanical properties, low sensitivity to manufacturing defects, mechanical stability, and high energy absorption. However, they also present some challenges related to quality control, which can prevent their successful application. In fact, the optimization of the AM process is impossible without considering structural characteristics as manufacturing accuracy, internal defects, as well as surface topography and roughness. In this study, the quantitative non-destructive analysis of TPMSS manufactured from Ti-6Al-4V alloy by electron beam melting was performed by means of X-ray computed tomography (XCT). Several advanced image analysis workflows are presented to evaluate the effect of build orientation on wall thicknesses distribution, wall degradation, and surface roughness reduction due to the chemical etching of TPMSS. It is shown that the manufacturing accuracy differs for the structural elements printed parallel and orthogonal to the manufactured layers. Different strategies for chemical etching show different powder removal capabilities and both lead to the loss of material and hence the gradient of the wall thickness. This affects the mechanical performance under compression by reduction of the yield stress. The positive effect of the chemical etching is the reduction of the surface roughness, which can potentially improve the fatigue properties of the components. Finally, XCT was used to correlate the amount of retained powder with the pore size of the functionally graded TPMSS, which can further improve the manufacturing process. KW - Metamaterials KW - Functionally graded porous structure KW - Triply periodic minimal surface structures KW - Roughness analysis KW - Powder removal KW - Deep learning segmentation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528142 DO - https://doi.org/10.3390/ma14113002 VL - 14 IS - 11 SP - 3002 PB - MDPI AN - OPUS4-52814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Khrapov, D. A1 - Surmeneva, M. A1 - Koptioug, A. A1 - Evsevleev, Sergei A1 - Léonard, Fabien A1 - Bruno, Giovanni A1 - Surmenev, R. T1 - X-ray computed tomography of multiple-layered scaffolds with controlled gradient cell lattice structures fabricated via additive manufacturing N2 - In this paper we report on the characterization by X-ray computed tomography of calcium phosphate (CaP) and polycaprolactone (PCL) coatings on Ti-6Al-4V alloy scaffolds used as a material for medical implants. The cylindrical scaffold has greater porosity of the inner part than the external part, thus, mimicking trabecular and cortical bone, respectively. The prismatic scaffolds have uniform porosity. Surface of the scaffolds was modified with calcium phosphate (CaP) and polycaprolactone (PCL) by dip-coating to improve biocompatibility and mechanical properties. Computed tomography performed with X-ray and synchrotron radiation revealed the defects of structure and morphology of CaP and PCL coatings showing small platelet-like and spider-web-like structures, respectively. KW - Additive manufacturing KW - Lattice structure KW - Multiple-layered scaffold KW - Coating KW - Medical implants KW - Computed tomography KW - Polycaprolactone KW - Calcium phosphate PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471931 UR - http://stacks.iop.org/1742-6596/1145/i=1/a=012044 DO - https://doi.org/10.1088/1742-6596/1145/1/012044 SN - 1742-6596 VL - 1145 SP - 012044, 1 EP - 7 PB - IOP AN - OPUS4-47193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Khrapov, D. A1 - Surmeneva, M. A1 - Koptioug, A. A1 - Evsevleev, Sergei A1 - Léonard, Fabien A1 - Bruno, Giovanni A1 - Surmenev, R. T1 - X-ray computed tomography of multiple-layered scaffolds with controlled gradient cell lattice structures fabricated via additive manufacturing N2 - In this paper we report on the characterization by X-ray computed tomography of calcium phosphate (CaP) and polycaprolactone (PCL) coatings on Ti-6Al-4V alloy scaffolds used as a material for medical implants. The cylindrical scaffold has greater porosity of the inner part than the external part, thus, mimicking trabecular and cortical bone, respectively. The prismatic scaffolds have uniform porosity. Surface of the scaffolds was modified with calcium phosphate (CaP) and polycaprolactone (PCL) by dip-coating to improve biocompatibility and mechanical properties. Computed tomography performed with X-ray and synchrotron radiation revealed the defects of structure and morphology of CaP and PCL coatings showing small platelet-like and spider-web-like structures, respectively.  KW - Mechanical Engineering KW - Maskinteknik PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510763 DO - https://doi.org/10.1088/1742-6596/1145/1/012044 SN - 17426588 VL - 1145 SP - 012044 PB - IOP AN - OPUS4-51076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Duarte-Ruiz, D. A1 - Saßnick, H.-D. A1 - Ferreira De Araujo, F. A1 - Gentzmann, Marie A1 - Huthwelker, T. A1 - Cocchi, C T1 - X-ray absorption spectroscopy of scandium oxide polymorphs N2 - Scandium oxide (Sc2O3) is a rare-earth oxide with significant potential in key technological areas, but due to its limited supply a deep understanding of its characteristics in different crystalline phases is still missing. Here, we present a combined experimental and ab initio X-ray absorption spectroscopy investigation of Sc2O3 focusing on excitations from the O K-edge and the Sc L2,3-edge. While measurements are performed on a cubic sample, the most stable phase under ambient conditions, six different polymorphs are computed, including two high-pressure phases with a trigonal and monoclinic lattice in addition to the cubic phase, as well as three computationally predicted structures. Our analysis of the structural and electronic properties reveals significant similarities between the cubic polymorph and the high-pressure trigonal phase, while the monoclinic crystal exhibits distinct features. The spectra simulated for these similar phases from the solution of the Bethe–Salpeter equation show very good agreement with measurements. Additional comparison with results computed in the independent-particle approximation highlights the dominant role of electron–hole correlations in shaping the absorption features, particularly at the O K-edge, where a common pattern with the features of other sesquioxides is identified. Our findings offer new insight into the spectral fingerprints of Sc2O3 polymorphs, aiding in situ characterization and informing sustainable materials management. KW - Scandium PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650806 DO - https://doi.org/10.1039/d5ra06446e VL - 15 IS - 56 SP - 47814 EP - 47825 AN - OPUS4-65080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaudhuri, Somsubhro A1 - Krankenhagen, Rainer A1 - Lapšanská, Ivana A1 - Stamm, Michael T1 - WTB-IRT: Modelling and Measurement of Thermal Contrast in Wind Turbine Rotor Blades (WTBs) N2 - The rapid growth of wind energy infrastructure over the past two to three decades has led to an urgent need for advanced non-destructive testing (NDT) methods—both for newly installed wind turbine blades (WTBs) and for ageing components nearing the end of their service life. Among emerging techniques, passive infrared thermography (IRT) offers a promising solution by enabling contactless, time-efficient inspection based on naturally occurring thermal variations. The effectiveness of passive IRT depends on the presence of sufficient thermal contrast to distinguish surface features, subsurface structures, and defects. To better understand the possibility of obtaining such contrast in composite structures such as WTBs, a controlled study was carried out on a blade section exposed to programmed temperature transients in a climate chamber. Infrared measurements were recorded, and the thermal behaviour of the specimen was simulated using finite element models (FEM) in COMSOL Multiphysics 6.3. Although direct validation is limited by measurement uncertainties and transient effects, the comparison provides insight into the capabilities and limitations of FEM in replicating real-world thermal behaviour. This paper focuses specifically on the challenges related to the modelling approach. T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025) CY - Kobe, Japan DA - 15.09.2025 KW - Thermography KW - Wind energy KW - Wind turbine rotor blades KW - Windenergie Anlage Rotorblätter KW - FEA PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642308 DO - https://doi.org/10.3390/proceedings2025129015 VL - 129 IS - 1 SP - 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-64230 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nehring, Grzegorz A1 - Bonnerot, Olivier A1 - Gordon, N. A1 - Rabin, Ira T1 - Writing and Correcting a Torah Scroll in Germany of the Thirteenth and Fourteenth Centuries N2 - Scientific material analysis of the elemental composition of inks from different strata of a manuscript has the potential to complement scholarly observations using palaeography and philology in reconstructing the history of the manuscript’s production, correction and repair. There are three typologically different classes of black writing inks: soot inks consist of carbon particles. KW - Manuscript studies KW - Hebrew studies KW - Ink analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540658 DO - https://doi.org/10.25592/uhhfdm.9749 VL - Comparative Oriental Manuscript Studies Bulletin 7, 2021 IS - 7 SP - 2 EP - 20 PB - Centre for the study of manuscript cultures CY - Hamburg AN - OPUS4-54065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Katrin A1 - Schmitt Rahner, M. A1 - Stolzenberg, U. A1 - Kraft, Sebastian A1 - Bonse, Jörn A1 - Feist, C. A1 - Albrecht, D. A1 - Pullner, B. A1 - Krüger, Jörg T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2. KW - Ultrashort pulsed laser KW - X-ray emission KW - X-ray spectrum KW - X-ray energies KW - Radiation protection PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176 DO - https://doi.org/10.3390/ma15248996 VL - 15 IS - 24 SP - 1 EP - 17 PB - MDPI AN - OPUS4-56617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rühle, Bastian A1 - Krumrey, Julian Frederic A1 - Hodoroaba, Vasile-Dan T1 - Workflow towards automated segmentation of agglomerated, non‑spherical particles from electron microscopy images using artificial neural networks N2 - We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from scanning electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. The whole process only requires about 15 minutes of hands-on time by a user and can typically be finished within less than 12 hours when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. We compare the segmentation masks obtained with our suggested workflow qualitatively and quantitatively to state-of-the-art methods using various metrics. Finally, we used the segmentation masks for automatically extracting particle size distributions from the SEM images of TiO2 particles, which were in excellent agreement with particle size distributions obtained manually but could be obtained in a fraction of the time. KW - Electron microscopy KW - Neural networks KW - Artificial intelligence KW - Image segmentation KW - Automated image analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522454 DO - https://doi.org/10.1038/s41598-021-84287-6 VL - 11 IS - 1 SP - 4942 PB - Springer Nature AN - OPUS4-52245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias ED - Alexander, M.G. ED - Beushausen, H. ED - Dehn, F. ED - Moyo, P. T1 - Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs N2 - Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - Grouting KW - Repair KW - Box-Behnken KW - Supplementary cementitious materials KW - Analysis of variance PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464769 DO - https://doi.org/10.1051/matecconf/201819907006 SN - 2261-236X VL - 199 SP - 07006-1 EP - 07006-7 PB - MATEC Web of Conferences AN - OPUS4-46476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winterkorn, René A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Wire arc additive manufacturing with novel Al-Mg-Si filler wire - Assessment of weld quality and mechanical properties N2 - Wire arc additive manufacturing enables the production of near-net shape large-volume metallic components leveraging an established industrial base of welding and cladding technology and adapting it for layer-wise material deposition. However, the complex relationship between the process parameters and resulting mechanical properties of the components still remains challenging. In case of high-strength Al-Mg-Si aluminum alloys, no commercial filler wires are yet available due the high susceptibility of solidification cracking as well as the necessary efforts to obtain acceptable mechanical properties. To address this need, we evaluated a novel filler wire based on AlMg0.7Si doped with a Ti5B1 master alloy to foster fine equiaxed grains within the deposited metal. The correlation between the process parameters and component quality was examined by analyzing the size and distribution of pores as well as the grain morphology. Furthermore, we evaluated the influence of different post-weld heat treatment strategies to achieve mechanical properties corresponding to the reference wrought material. We demonstrated that fine equiaxed grains in the weld metal reduced the susceptibility of solidification cracking significantly. The novel AlMg0.7Si-TiB (S Al 6063-TiB) filler wire facilitated wire arc additive manufacturing of high-strength aluminum components with mechanical properties that were almost as superior as the corresponding wrought base material. KW - Wire arc additive manufacturing KW - Precipitation hardening aluminum alloys KW - AlMg0.7SiTiB filler wire KW - Grain refinement KW - Mechanical properties PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538327 DO - https://doi.org/10.3390/met11081243 SN - 2075-4701 VL - 11 IS - 8 SP - 1 EP - 13 PB - MDPI CY - Basel AN - OPUS4-53832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Ou, D. A1 - Ghafafian, Carineh A1 - Zscherpel, Uwe A1 - Trappe, Volker T1 - Wind turbine rotor blade testing by dual-energy laminography N2 - Modern wind turbine rotor blades consist of sandwich shell segments made from glass fiber reinforced polymers. During manufacturing, defects can arise which could lead to failure of the whole component under dynamic mechanical and thermal loads. Hence during operation defects can arise which, if detected, can be repaired locally and in-situ by applying repair patches instead of taking the whole rotor blade down and repair it remotely. This method is much more time and cost effective, since the shut-down time of the energy converter is limited to a minimum. These repair patches can, however, also lead to new defects if not applied optimally. Therefore, it is necessary to control the quality of the repair patches to ensure the best possible restoration of structural integrity of the component. As a rotor blade is an object with a large aspect ratio, X-ray laminography is predestined to provide 3D information of the objective volume. To enhance the amount of information gained from laminographic reconstruction, we use in this study a photon counting and energy discriminating X-ray detector and apply a material decomposition algorithm to the data. By inherently separating the incident spectra within the detection process into two distinct energy bins, the basis material decomposition can provide material resolved images. Choosing glass and epoxy resin as basis materials and numerically solving the inverse dual-energy equation system, the reconstructed laminographic datasets contain highly valuable information about the distribution of the basis materials within the structure. Furthermore, cross- artifacts arising from the limited angle of the projection data can be reduced by this method which allows to investigate structures that were hidden underneath the artefacts. T2 - International Symposium on Digital Industrial Radiology and Computed Tomography – DIR2019 CY - Fürth, Germany DA - 02.07.2019 KW - Laminography KW - Wind energy KW - Fiber reinforced polymer KW - Photon counting detector KW - Repair patch PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484380 UR - https://www.dir2019.com/portals/dir2019/bb/Tu.3.A.1.pdf SN - 978-947971-06-0 SP - 1 EP - 13 AN - OPUS4-48438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kozachynskyi, Volodymyr A1 - Hoffmann, Christian A1 - Esche, Erik T1 - Why fixing alpha in the NRTL model might be a bad idea – Identifiability analysis of binary vapor-liquid equilibria N2 - New vapor-liquid equilibrium (VLE) data are continuously being measured and new parameter values, e.g., for the nonrandom two-liquid (NRTL) model are estimated and published. The parameter α, the nonrandomness parameter of NRTL, is often not estimated but is heuristically fixed to a constant value based on the involved components. This can be seen as a manual application of a (subset selection) regularization method. In this work, the practical parameter identifiability of the NRTL model for describing the VLE is analyzed. It is shown that fixing α is not always a good decision and sometimes leads to worse prediction properties of the final parameter estimates. Popular regularization techniques are compared and Generalized Orthogonalization is proposed as an alternative to this heuristic. In addition, the sequential Optimal Experimental Design and Parameter Estimation (sOED-PE) method is applied to study the influence of the regularization methods on the performance of the sOED-PE loop. KW - NRTL KW - VLE KW - Nonlinear programming KW - Model-based optimal experimental design PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623605 DO - https://doi.org/10.1016/j.ces.2024.121122 VL - 305 SP - 1 EP - 18 PB - Elsevier Ltd. AN - OPUS4-62360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meiling, T. A1 - Cywinski, P. A1 - Bald, Ilko T1 - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis N2 - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly Brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst. KW - Carbon dots KW - Quantum yield KW - Fluorescence KW - Nanoparticles PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367204 DO - https://doi.org/10.1038/srep28557 VL - 6 SP - Article 28557, 1 EP - 9 PB - Nature Publishing Group AN - OPUS4-36720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidinger, J. A1 - Barkov, V. A1 - Tavakoli, H. A1 - Correa, J. A1 - Ostermann, Markus A1 - Atzmueller, M. A1 - Gebbers, R. A1 - Vogel, S. T1 - Which and how many soil sensors are ideal to predict key soil properties: A case study with seven sensors N2 - Soil sensing enables rapid and cost-effective soil analysis. However, a single sensor often does not generate enough information to reliably predict a wide range of soil properties. Within a case-study, our objective was to identify how many and which combinations of soil sensors prove to be suitable for high-resolution soil mapping. On a subplot of an agricultural field showing a high spatial soil variability, six in-situ proximal soil sensors (PSSs) next to remote sensing (RS) data from Sentinel-2 were evaluated based on their capabilities to predict a set of soil properties including: soil organic carbon, pH, moisture as well as plant-available phosphorus, magnesium and potassium. The set of PSSs consisted of ion-selective pH electrodes, a capacitive soil moisture sensor, an apparent soil electrical conductivity measuring system as well as passive gamma-ray-, X-ray fluorescence- and nearinfrared spectroscopy. All possible combinations of sensors were exhaustively evaluated and ranked based on their predict KW - XRF KW - Soil KW - Remote Sensing KW - Precision agriculture PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613920 DO - https://doi.org/10.1016/j.geoderma.2024.117017 VL - 450 SP - 1 EP - 17 PB - Elsevier B.V. AN - OPUS4-61392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Helman-Wasny, Agnieszka ED - Martin, E. ED - Brox, T. ED - Lange, D. T1 - What makes ‘Tibetan paper’ Tibetan? Understanding the materiality of Tibetan paper N2 - Paper, as a writing support, is an integral element of the materiality of Tibetan books together with the technologies of their production. Analysis of the material features of the paper used in Tibetan written artefacts can help us to unravel their provenance, which is often unknown. First, however, we need a relatively clear understanding of the characteristic features of paper produced within particular book cultures and geographical regions at particular periods of time. This chapter offers a starting point by discussing the general characteristics of paper that originated in Tibet. Drawing on macro- and microscopic studies, it highlights the wide variety of paper types that have been used as writing supports in Tibetan written artefacts, before examining in more detail the raw materials, papermaking technologies and processes, and writing surface preparations that might justify the descriptor ‘Tibetan’ and thus grant Tibetan identity to paper. KW - Written artefacts KW - Paper KW - Tibet PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649288 SN - 978-3-98887-016-2 DO - https://doi.org/10.11588/hasp.1522 SP - 113 EP - 146 PB - Heidelberg Asian Studies Publishing (HASP) CY - Heidelberg AN - OPUS4-64928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Scheliga, F. A1 - Weidner, Steffen T1 - What does conversion mean in polymer science? N2 - The definition of the term “conversion” is discussed for a variety of polymer syntheses. It is demonstrated that in contrast to organic and inorganic chemistry several different definitions are needed in polymer science. The influence of increasing conversion on structure and topology of homo- and Copolymers is illustrated. Chain-growth polymerizations, such as radical polymerization or living anionic polymerizations of vinyl monomers, condensative chain polymerization, two and three-dimensional step-growth polymerizations, ring–ring or chain–chain equilibration and chemical modification of polymers are considered. KW - Polymers KW - Polymerization KW - Conversion KW - Polycondensation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523597 DO - https://doi.org/10.1002/macp.202100010 VL - 222 IS - 8 SP - 10 PB - Wiley VCH AN - OPUS4-52359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baller, Johannes A1 - Hilger, André A1 - Qi, Naiyu A1 - Morini, Chiara A1 - Cornelio, Andrea A1 - Remhof, Arndt A1 - Osenberg, Markus A1 - Manke, Ingo A1 - Moosmann, Julian A1 - Beckmann, Felix A1 - Graeber, Gustav T1 - Wetting Interactions Between Porous Carbon Hosts and Liquid Sodium‐Potassium Alloys Toward Their Use in Negative Electrodes of Alkali‐Metal Batteries N2 - Batteries with liquid alkali‐metal negative electrodes offer a route to compact, high‐performance energy storage. Innovation in alkali‐metal management, i.e., controlled storage, release and transport of liquid alkali metal, can enable simpler and cheaper cell designs. Porous carbons have emerged as potential host materials for liquid alkali metals. Here, X‐ray computed tomography is used to study the wetting interactions between porous carbon hosts and liquid sodium‐potassium alloy (NaK) as a function of carbon host morphology and surface functionalization. While as‐received carbon samples show no affinity toward NaK, heat‐treated carbon is spontaneously infiltrated with NaK filling almost the entire pore volume. It is explored how forced wetting partially fills pores of NaK‐repellant hosts, showing large differences in pore filling based on the average pore size of the host material. In electrochemical discharge experiments, it is shown that both as‐received and heat‐treated carbon felt enable high areal capacities beyond 40 mAh cm−2. However, the heat‐treated carbon shows ten times lower overpotential. Finally, it is demonstrated how heat‐treated carbon felt can enable capillary transport of NaK. In summary, this study elucidates important aspects of the interactions between liquid alkali metals and porous carbon hosts, generating insights into possible applications in liquid alkali‐metal batteries. KW - Battery KW - Solid electrolyte KW - Sodium KW - Wetting PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644663 DO - https://doi.org/10.1002/adfm.202523169 SN - 1616-301X SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-64466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Welding with high-power lasers: trends and developments N2 - High-power laser beam welding became new stimuli within the last 10 years due to the availability of a new generation of high brightness multi kilowatt solid state lasers. In the welding research new approaches have been developed to establish reliable and praxis oriented welding processes meeting the demands of modern industrial applications during this time. The paper focuses on some of the current scientific and technological aspects in this research field like hybrid laser arc welding, simulation techniques, utilization of electromagnetic fields or reduced pressure environment for laser beam welding processes, which contributed to the further development of this technology or will play a crucial role in its further industrial implementation. T2 - 9th International Conference on Photonic Technologies - LANE 2016 CY - Fürth, Germany DA - 19.09.2016 KW - High-power Laserbeam Welding KW - Electromagnetic Force KW - Vacuum KW - Simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377280 DO - https://doi.org/10.1016/j.phpro.2016.08.003 VL - 83 SP - 15 EP - 25 PB - Elsevier B.V. CY - Berlin, Germany AN - OPUS4-37728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artinov, Antoni A1 - Bakir, Nasim A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Weld pool shape observation in high power laser beam welding N2 - The geometry of the melt pool in laser beam welding plays a major role to understand the dynamics of the melt and its solidification behavior. In this study, a butt configuration of 15 mm thick structural steel and transparent quartz glass was used to observe the weld pool geometry by means of high-speed camera and an infrared camera recording. The observations show that the dimensions of the weld pool vary depending on the depth. The areas close to the weld pool surface take a teardrop-shape. A bulge-region and its temporal evolution were observed approximately in the middle of the depth of the weld pool. Additionally, a 3D transient thermal-fluid numerical simulation was performed to obtain the weld pool shape and to understand the formation mechanism of the observed bulging effect. The model takes into account the local temperature field, the effects of phase transition, thermo-capillary convection, natural convection and temperature-dependent material properties up to evaporation temperature. The numerical results showed good accordance and were furthermore used to improve the understanding of the experimentally observed bulging effect. T2 - LANE Conference 2018 CY - Fürth, Germany DA - 03.09.2018 KW - High power laser beam welding KW - Weld pool shape KW - Bulging KW - Numerical process simulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458759 DO - https://doi.org/10.1016/j.procir.2018.08.043 SN - 2212-8271 VL - 74 SP - 683 EP - 686 PB - Elsevier Ltd. CY - Amsterdam [u.a.] AN - OPUS4-45875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jauregui Rozo, Maria A1 - Sunder, S. A1 - Inasu, S. A1 - Meinel, Dietmar A1 - Ruckdäschel, H. A1 - Schartel, Bernhard T1 - Weaving Through Fire and Force: Fire Behavior and Fire Stability of Unidirectional, Bidirectional, and Woven Roving Glass-Fiber Composites N2 - This study systematically investigates the transfer of flame retardants (FRs) from epoxy resins to composites. The flame-retardant composites are formulated using bisphenol A diglycidyl ether as the resin and dicyandiamide as the hardener, reinforced with glass fibers (GFs) using various textile architectures: unidirectional (UD), bidirectional (BD), and woven rovings (WR). These composites are evaluated using bench-scale fire stability tests and cone calorimeter experiments to assess critical parameters, including the temperature at failure, time to failure, and fire behavior. Among the tested configurations, UD-GFs demonstrate superior flame retardancy, fire stability, flammability, and mechanical performance, attributed to their higher residue yield, forming a more efficient protective char layer. However, the addition of FRs is limited by their impact on the material's mechanical properties. When the FR content increases to 30 and 50 wt.% of the resin, the composites exhibit a decrease in mechanical performance, adversely affecting both time to failure and temperature at failure. While adding FRs reduces the risk of fire propagation, it does not substantially enhance fire stability or mechanical performance. KW - Fire Resistance KW - Fiber-Reinforced Polymer Composites KW - Fire Stability KW - Glass Fibers KW - Fire Behavior PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631220 SN - 1438-7492 SN - 1439-2054 VL - 310 IS - 5 SP - 2400432 PB - Wiley VHC-Verlag AN - OPUS4-63122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chaudhuri, Somsubhro A1 - Stamm, Michael A1 - Krankenhagen, Rainer T1 - Weather-dependent passive thermography and thermal simulation of in-service wind turbine blades N2 - . To cope with the increase in the manufacturing and operation of wind turbines, wind farm operators need inspection tools that are able to provide reliable information while keeping the downtime low. Current inspection techniques require to stop the wind turbine. This work presents the current progress in the project EvalTherm, in which passive thermography is evaluated as a possible non-destructive inspection tool for operational wind turbine blades (WTBs). A methodology to obtain thermal images of rotating WTBs has been established in this project. However, the quality of the results is heavily dependent on various aspects such as weather conditions, information on the inspected WTB, damage history, etc. In this work, a section of a used WTB is simulated using finite-element modelling (FEM) as well as experimentally tested for evaluating the accuracy of the model. Such a model will provide insight into the potential thermal response of a certain structure (with specific material properties) in given weather (boundary) conditions. The model is able to provide satisfactory predictions of the thermal response of the structure, as well as indicate what thermal contrast(s) result from artificial defects introduced in the structure. T2 - WindEurope Annual Event 2023 CY - Copenhagen, Denmark DA - 25.04.2023 KW - FEM KW - Thermografie KW - Wind turbine rotor blades KW - Windenergie Anlage Rotorblätter PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582777 DO - https://doi.org/10.1088/1742-6596/2507/1/012025 VL - 2507 SP - 1 EP - 12 PB - IOP Publishing Ltd. AN - OPUS4-58277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graebner, Maraike A1 - Giese, Marcel A1 - Lorenz, Svenja A1 - Treutler, Kai A1 - Schröpfer, Dirk A1 - Wesling, Volker A1 - Kannengießer, Thomas T1 - Wear resistance of modified NiMoCrSi claddings in relation to the resulting surface machinability via ultrasonic-assisted milling N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses). KW - Colmonoy C56 KW - PTA welding KW - Adhesive wear KW - Abrasive wear KW - Ultrasonic-assisted milling process KW - Surface integrity KW - Service life and efficiency KW - Substitution of critical raw materials PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651530 DO - https://doi.org/10.1016/j.wear.2025.205830 SN - 0043-1648 VL - 571 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Wavelength-scanning distributed acoustic sensing for structural monitoring and seismic applications N2 - We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable. T2 - 7th International Symposium on Sensor Science CY - Napoli, Italy DA - 09.05.2019 KW - Optical fiber sensor KW - Distributed acoustic sensor (DAS) KW - Optical time domain reflectometry KW - Rayleigh scattering KW - Artificial neural networks KW - Structural health monitoring KW - Seismic measurement PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487733 DO - https://doi.org/10.3390/proceedings2019015030 SN - 2504-3900 VL - 15 SP - Paper 30, 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-48773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Wavelength-scanning coherent OTDR for dynamic high strain resolution sensing N2 - Distributed vibration sensing in optical fibers opened entirely new opportunities and penetrated various sectors from security to seismic monitoring. Here, we demonstrate a most simple and robust approach for dynamic strain measurement using wavelength-scanning coherent optical time domain reflectometry (C-OTDR). Our method is based on laser current modulation and Rayleigh backscatter shift correlation. As opposed to common single-wavelength phase demodulation techniques, also the algebraic sign of the strain change is retrieved. This is crucial for the intended applications in structural health monitoring and modal analysis. A linear strain response down to 47.5 pε and strain noise of 100 pε/√Hz is demonstrated for repetition rates in the kHz range. A field application of a vibrating bridge is presented. Our approach provides a cost-effective high-resolution method for structural vibration analysis and geophysical applications. KW - Fiber optics sensors KW - Optical time domain reflectometry KW - Rayleigh Scattering KW - Distributed acoustic sensing KW - Distributed strain sensing PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448069 DO - https://doi.org/10.1364/OE.26.010573 SN - 1094-4087 VL - 26 IS - 8 SP - 10573 EP - 10588 PB - Optical Society of America AN - OPUS4-44806 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liao, Chun-Man A1 - Niederleithinger, Ernst A1 - Bernauer, F A1 - Igel, H A1 - Hadziioannou, Céline T1 - Wave-Screening Methods for Prestress-Loss Assessment of a Large-Scale Post-Tensioned Concrete Bridge Model Under Outdoor Conditions N2 - This paper presents advancements in structural health monitoring (SHM) techniques, with a particular focus on wave-screening methods for assessing prestress loss in a large-scale prestressed concrete (PC) bridge model under outdoor conditions. The wave-screening process utilizes low-frequency wave propagation obtained from seismic interferometry of structural free vibrations and high-frequency wave propagation obtained through ultrasonic transducers embedded in the structure. An adjustable post-tensioning system was employed in a series of experiments to simulate prestress loss. By comparing bridge vibrations under varying post-tensioning forces, the study investigated prestress loss and examined temperature-related effects using the coda wave interferometry (CWI) method. Local structural alterations were analyzed through wave velocity variations, demonstrating sensitivity to bridge temperature changes. The findings indicate that wave-based methods are more effective than traditional modal analysis for damage detection, highlighting the dual impacts of prestress loss and temperature, as well as damage localization. This study underscores the need for long-term measurements to account for temperature fluctuations when analyzing vibration measurements to investigate changes in prestressing force in PC structures. KW - Coda wave interferometry KW - Damage detection KW - Prestress loss KW - Seismic interferometry KW - SHM KW - Temperature influence KW - Ultrasonics KW - Wave-screening PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634244 UR - https://www.mdpi.com/2076-3417/15/11/6005 DO - https://doi.org/10.3390/app15116005 VL - 15 IS - 11 SP - 1 EP - 18 PB - MDPI AN - OPUS4-63424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nitz, Phillip D. H. A1 - Rosaz, Paul A1 - Kreysina, Daniela A1 - Kasprzak, Dawid A1 - Qi, Naiyu A1 - Baller, Johannes A1 - Graeber, Gustav T1 - Water-in-Salt Electrolytes Embedded in Polyacrylamide Hydrogels: A First Step toward Deformable Sodium-Ion Batteries N2 - The development of flexible, safe, and sustainable Energy storage systems is critical for next-generation technologies, including wearable electronics, biomedical devices, and soft robotics. In this work, we provide a systematic investigation of sodium perchlorate-based water-in-salt (WIS) electrolytes embedded in polyacrylamide (PAM) hydrogels as a potential platform for deformable sodium-ion batteries or aqueous supercapacitors. Using Raman spectroscopy, we track the transition from free to intermediate water states with increasing salt concentration, identifying the onset of the WIS regime around 10 mol kg−1. Electrochemical measurements reveal that both the aqueous and hydrogel-based electrolytes exhibit a broadened electrochemical stability window (ESW) at higher salt concentrations, reaching up to 2.75 V. Impedance spectroscopy shows that while aqueous electrolytes achieve higher peak conductivity (156 mS cm−1), hydrogel-based electrolytes offer greater stability across a range of concentrations. This observation was supported by cyclic voltammetry, as it showed enhanced electrochemical stability of the PAM hydrogel compared to the aqueous electrolyte. This comprehensive and systematic study demonstrates that highly concentrated WIS electrolytes can be successfullyembedded into PAM hydrogels, while preserving good electrochemical stability and ionic conductivity. This could make them a promising foundation for all-hydrogel, sodium-based energy storage devices that are safe, sustainable, and mechanically compliant. KW - Battery PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653156 DO - https://doi.org/10.1021/acsapm.5c03031 SN - 2637-6105 SP - 1 EP - 8 PB - American Chemical Society (ACS) AN - OPUS4-65315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yao, J. A1 - Jiang, T. A1 - Ji, Y. A1 - An-Stepec, Biwen Annie A1 - Koerdt, Andrea A1 - Cai, Z. A1 - Dong, C. A1 - Ge, Y. A1 - Qi, Z. T1 - Water-Fueled Autocatalytic Bactericidal Pathway based on e-Fenton-Like Reactions Triggered by Galvanic Corrosion and Extracellular Electron Transfer N2 - Water is generally considered to be an undesirable substance in fuel system, which may lead to microbial contamination. The antibacterial strategies that can turn water into things of value with high disinfection efficacy have been urgently needed for fuel system. Here, we reveal a water-fueled autocatalytic bactericidal pathway comprised by bi-metal micro-electrode system, which can spontaneously produce reactive oxygen species (mainly H2O2 and O2•–) by the electron Fenton-like reaction in water medium without external energy., The respiratory chain component of bacteria and the galvanic corrosion on the coated metals were two electron sources in the system. The specific model of Ag-Ru water-fueled autocatalytic (WFA) microelectrode particles presents extremely high disinfection efficiency (>99.9999%) in less than one hour for three aerobic bacteria (Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis) in LB media and high disinfection efficiency for the anaerobic bacteria (Desulfovibrio alaskensis) in Postgate E media without natural light irradiation. Overall, the novel WFA Ag-Ru antibacterial material explored in this study has a high potential for sterilizing applications in fuel system and this work provides the potential for the development of non-chemical and water-based antibacterial materials, such as WFA Ag-Ru antibacterial coating on stainless steel. KW - Fenton-like reaction KW - Reactive oxygen species KW - Disinfection Fuel KW - Silver KW - Ruthenium KW - MIC PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555186 DO - https://doi.org/10.1016/j.jhazmat.2022.129730 SN - 0304-3894 VL - 440 SP - 1 EP - 11 PB - Elsevier CY - Amsterdam AN - OPUS4-55518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balzer, R. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Kiefer, P. A1 - Deubener, J. A1 - Fechtelkord, M. T1 - Water in Alkali Aluminosilicate Glasses N2 - To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses. KW - NMR spectroscopy KW - Alkali aluminosilicate glasses KW - Water speciation KW - Glass transition KW - Infrared spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509497 DO - https://doi.org/10.3389/fmats.2020.00085 VL - 7 SP - 85 AN - OPUS4-50949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silveira, A. A1 - Kardjilov, N. A1 - Markötter, Henning A1 - Longo, E. A1 - Greving, I. A1 - Lasch, P. A1 - Shahar, R A1 - Zaslansky, P. T1 - Water flow through bone: Neutron tomography reveals differences in water permeability between osteocytic and anosteocytic bone material N2 - Vertebrate bones are made of a nanocomposite consisting of water, mineral and organics. Water helps bone material withstand mechanical stress and participates in sensation of external loads. Water diffusion across vertebrae of medaka (bone material lacking osteocytes) and zebrafish (bone material containing osteocytes) was compared using neutron tomography. Samples were measured both wet and following immersion in deuterated-water (D2O). By quantifying H+ exchange and mutual alignment with X-ray lCT scans, the amount of water expelled from complete vertebra was determined. The findings revealed that anosteocytic bone material is almost twice as amenable to D2O diffusion and H2O exchange, and that unexpectedly, far more water is retained in osteocytic zebrafish bone. Diffusion in osteocytic bones (only 33 % – 39 % water expelled) is therefore restricted as compared to anosteocytic bone (~ 60 % of water expelled), presumably because water flow is confined to the lacunar-canalicular network (LCN) open-pore system. Histology and Raman spectroscopy showed that anosteocytic bone contains less proteoglycans than osteocytic bone. These findings identify a previously unknown functional difference between the two bone materials. Therefore, this study proposes that osteocytic bone retains water, aided by non-collagenous proteins, which contribute to its poroelastic mechano-transduction of water flow confined inside the LCN porosity. KW - Bone porosity KW - Anosteocytic bone KW - Water permeability KW - Neutron tomography KW - Proteoglycans PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564563 DO - https://doi.org/10.1016/j.matdes.2022.111275 VL - 224 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-56456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilhelm, Stefan A1 - Kaiser, Martin A1 - Würth, Christian A1 - Heiland, J. A1 - Carrillo-Carrion, C. A1 - Muhr, V. A1 - Wolfbeis, Otto S. A1 - Parak, W.J. A1 - Resch-Genger, Ute A1 - Hirsch, T. T1 - Water dispersible upconverting nanoparticles: effects of surface modification on their luminescence and colloidal stability N2 - We present a systematic study on the effect of surface ligands on the luminescence properties and colloidal stability of β-NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs), comparing nine different surface coatings to render these UCNPs water-dispersible and bioconjugatable. A prerequisite for this study was a large-scale synthetic method that yields ~2 g per batch of monodisperse oleate-capped UCNPs providing identical core particles. These ~23 nm sized UCNPs display an upconversion quantum yield of ~0.35% when dispersed in cyclohexane and excited with a power density of 150 W cm-2, underlining their high quality. A comparison of the colloidal stability and luminescence properties of these UCNPs, subsequently surface modified with ligand exchange or encapsulation protocols, revealed that the ratio of the green (545 nm) and red (658 nm) emission bands determined at a constant excitation power density clearly depends on the surface chemistry. Modifications relying on the deposition of additional (amphiphilic) layer coatings, where the initial oleate coating is retained, show reduced non-radiative quenching by water as compared to UCNPs that are rendered water-dispersible via ligand exchange. Moreover, we could demonstrate that the brightness of the upconversion luminescence of the UCNPs is strongly affected by the type of surface modification, i.e., ligand exchange or encapsulation, yet hardly by the chemical nature of the ligand. KW - upconverting nanoparticles (UCNPs) KW - Luminescence KW - surface modification PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324071 DO - https://doi.org/10.1039/c4nr05954a SN - 2040-3364 SN - 2040-3372 VL - 7 IS - 4 SP - 1403 EP - 1410 PB - RSC Publ. CY - Cambridge AN - OPUS4-32407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dudziak, Mateusz A1 - Bhatia, Riya A1 - Dey, R. A1 - Falkenhagen, Jana A1 - Ullrich, M. S. A1 - Thomsen, C. A1 - Schartel, Bernhard T1 - Wastewater phosphorus enriched algae as a sustainable flame retardant in polylactide N2 - Revolutionizing our polymer industry for adaption to a sustainable carbon circular economy has become one of today’s most demanding challenges. Exploiting renewable resources to replace fossil-fuel—based plastics with biopolymers such as poly(lactic acid) (PLA) is inevitable while using waste streams as a raw material resource at least is promising. When it comes to using PLA as technical polymer, its high flammability must be addressed by flame retardants compatible with the thermoplastic processing of PLA and its compostability. This study proposes microalgae enriched with phosphorus from wastewater (P-Algae) as an elegant way towards a kind of sustainable organophosphorus flame retardant. The concept is demonstrated by investigating the processing, pyrolysis, flammability, and fire behavior of PLA/P-Algae, while varying the P-Algae content and comparing P-Algae with four alternative bio-fillers (phosphorylated lignin, biochar, thermally treated sewage sludge, and metal phytate) with different P-contents as meaningful benchmarks. KW - PLA KW - Flame Retardancy KW - Phosphorylated Algae KW - Wastewater flame retardants KW - Zink phytate KW - Phosphorylated lignin KW - Thermally treated sludge PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604150 DO - https://doi.org/10.1016/j.polymdegradstab.2024.110885 SN - 1873-2321 SN - 0141-3910 VL - 227 SP - 1 EP - 11 PB - Elsevier Ltd. AN - OPUS4-60415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raniro, H.R. A1 - Soares, T.de M. A1 - Adam, Christian A1 - Pavinato, P.S. T1 - Waste-derived fertilizers can increase phosphorus uptake by sugarcane and availability in a tropical soil N2 - The use of highly water-soluble phosphorus (P) fertilizers can lead to P fixation in the soil, reducing fertilization efficiency. Waste-derived, low water-solubility sources can potentially increase sugarcane’s P uptake compared to triple superphosphate by reducing adsorption to the soil. Aims:We aimed to test struvite, hazenite, and AshDec® for their agronomic potential as recycled fertilizers for sugarcane production in a typical tropical soil.We hypothesize that these sources can reduce P fixation in the soil, increasing its availability and sugarcane’s absorption. Methods: In a greenhouse pot experiment, two consecutive sugarcane cycles, 90 days each, were conducted in a Ferralsol. The recovered sources struvite, hazenite, AshDec®, and the conventional triple superphosphate were mixed in the soil in three P doses (30, 60, and 90 mg kg–1), aside a control (nil-P). At both harvests, sugarcane number of sprouts, plant height, stem diameter, dry mass yield, shoot phosphorus, and soil P fractionation were investigated. Results: At 90 days, struvite and hazenite performed better for dry mass yield (70.7 and 68.3 g pot–1, respectively) than AshDec® and triple superphosphate (59.8 and 57.4 g pot–1, respectively) and for shoot P, with 98.1, 91.6, 75.6, and 66.3 mg pot–1, respectively. At 180 days, struvite outperformed all treatments for dry mass yield (95.3 g pot–1) and AshDec® (75.5 mg pot–1) for shoot P. Struvite was 38% and hazenite 21% more efficient than triple superphosphate in P uptake, while AshDec® was 6% less efficient. Soil had higher labile P under struvite, hazenite, and AshDec® than triple superphosphate by the end of the first cycle, while only the later increased nonlabile P by the end of the experiment (180 days). Conclusions:Waste-derived P sources were more efficient in supplying P for sugarcane and delivering labile P in 180 days than triple superphosphate. KW - AshDec KW - Hazenite KW - P-efficiency KW - Recycled sources KW - Struvite PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544216 DO - https://doi.org/10.1002/jpln.202100410 SN - 1436-8730 SP - 1 EP - 12 PB - Wiley-VCH GmbH AN - OPUS4-54421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Sanchez-Olivares, G. A1 - Rockel, Daniel A1 - Maldonado-Santoyo, M. A1 - Schartel, Bernhard T1 - Waste not, want not: The use of leather waste in flame retarded EVA N2 - Leather is among the most ancient, widely used materials worldwide. Industrial-scale leather production produces large quantities of organic waste attained during shaving and buffing steps during processing. In this study, leather wastes (LW) are used as fillers in flame retarded polymer composites. LW is investigated as a multifunctional bio-filler that enhances the fire performance of flame retarded poly(ethylene–vinyl acetate) (EVA) containing phosphorus flame retardants (P-FRs) ammonium polyphosphate (APP) or a melamine-encapsulated APP (eAPP). Using LW from tanneries as adjuvants to enhance P-FRs in EVA reduces industrial wastes that otherwise require costly waste management solutions. Materials are characterized multi-methodically via mechanical tests, electron microscopy, rheology, thermogravimetric analysis, evolved gas analysis, and condensed phase FTIR, also reaction-to-small-flames and cone calorimeter tests. EVA containing 10 wt-% LW and 20 wt-% P-FRs achieve 20% reductions in fire loads versus EVA, and up to 10% reduction in effective heats of combustion versus EVA with equal (30 wt-%) P-FR loadings. Enhanced char stabilization of EVA composites with LW and P-FRs lowered peaks of heat release rates up to 53% compared to EVA, and up to 40% compared to equal P-FRs loadings. Synergisms between LW and P-FRs in EVA are quantified. A chemical decomposition mechanism is proposed. KW - Leather waste KW - Tannery industry KW - EVA KW - Fire protection KW - Flame retardancy KW - Charring PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532977 DO - https://doi.org/10.1016/j.matdes.2021.110100 SN - 0264-1275 VL - 210 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam AN - OPUS4-53297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilhelm, Eugen A1 - Mente, Tobias A1 - Rhode, Michael T1 - Waiting time before NDT of welded offshore steel grades under consideration of delayed hydrogen-assisted cracking N2 - Offshore wind turbines (OWT) are a major goal of the energy strategy of Germany encompassing the increase of the installed wind power. OWT components are manufactured from welded steel plates with thicknesses up to 200 mm. The underlying standards and technical recommendations for construction of OWTs encompass specifications of so-called minimum waiting time (MWT) before non-destructive testing of the weld joints is allowed. Reason is the increased risk of time-delayed hydrogen assisted cold cracking as hydrogen diffusion is very slow due to the very thick plates. The strict consideration of those long MWT up to 48 h during the construction of OWTs leads to significant financial burden (like disproportionately high costs for installer ships as well as storage problems (onshore)). In this study, weld joints made of S355 ML were examined in comparison with the offshore steel grade S460 G2+M. The aim was to optimize, i.e., reduce, the MWT before NDT considering varied heat input, hydrogen concentration and using self-restraint weld tests. This would significantly reduce the manufacturing time and costs of OWT construction. To quantify the necessary delay time until hydrogen-assisted cold cracks appear, acoustic emission analysis was applied directly after welding for at least 48 h. KW - Hydrogen KW - Welding KW - Cracking KW - Offshore KW - Steel PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524959 DO - https://doi.org/10.1007/s40194-020-01060-5 SN - 0043-2288 VL - 65 SP - 947 EP - 959 PB - Springer Nature AN - OPUS4-52495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grauel, Bettina A1 - Würth, Christian A1 - Homann, C. A1 - Krukewitt, Lisa A1 - Andresen, Elina A1 - Roik, Janina A1 - Recknagel, Sebastian A1 - Haase, M. A1 - Resch-Genger, Ute T1 - Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals N2 - Despite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate backenergy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+ 4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and threephotonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission. The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a threedimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC. KW - Nano KW - Nanomaterial KW - Upconversion KW - Nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Pphotophysics KW - Lifetime KW - Sensor KW - Excitation KW - Power density KW - Single particle KW - Brightness KW - NIR KW - Mechanism KW - Modeling KW - Simulation KW - Energy transfer PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535317 DO - https://doi.org/10.1007/s12274-021-3727-y SN - 1998-0124 VL - 15 IS - 3 SP - 2362 EP - 2373 PB - Springer AN - OPUS4-53531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Olaf A1 - Horn, Wolfgang A1 - Richter, Matthias A1 - Jann, Oliver T1 - Volatile organic compounds from building products - Results from six round robin tests with emission test chambers conducted between 2008 and 2018 N2 - Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28 % in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51 %. KW - Construction product KW - Emission test chamber KW - Interlaboratory comparison KW - Proficiency testing KW - Rround robin test KW - VOC emission PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526139 DO - https://doi.org/10.1111/ina.12848 VL - 31 IS - 6 SP - 2049 EP - 2057 PB - Wiley AN - OPUS4-52613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Nils A1 - Dayani, Shahabeddin A1 - Markötter, Henning A1 - Schmidt, Anita A1 - Kowal, J. A1 - Lu, Y. A1 - Krug von Nidda, Jonas A1 - Bruno, Giovanni T1 - Visualization of stepwise electrode decomposition in a nail penetrated commercial lithium-ion cell using low-temperature synchrotron X-ray computed tomography N2 - The transition towards zero carbon emissions in power generation hinges on the integration of efficient electrical energy storage systems, with lithium-ion batteries (LIBs) positioned as a pivotal technology. While generally safe, deviations in their operational guidelines due to manufacturing defects or misuse can lead to critical safety concerns, notably thermal runaway (TR) events. Internal short circuits (ISCs) are primary initiators of TR within LIBs. For abuse testing, ISCs are often triggered by nail penetration. This study explores the morphological changes and mechanisms underlying ISC-induced TR in LIBs using operando synchrotron X-ray computed tomography (SXCT) at subzero temperatures. A novel cryogenic setup was developed to control a stepwise temperature increase in the damaged sample while monitoring electrochemical characteristics and simultaneously enabling acquisition of high-resolution SXCT images. The findings reveal that conducting nail penetration at minus 80°C prevents immediate TR, enabling detailed analysis of subsequent structural and electrochemical behavior during controlled thawing. Thus, the initiation of TR processes at localized ISC sites has been observed, evidenced by voltage fluctuations and morphological changes, such as cathode material cracking and decomposition. These results underscore the importance of temperature control in mitigating TR risks and provide critical insights into the internal dynamics of LIBs under abusive conditions. The developed cryogenic SXCT methodology offers a powerful tool for non-destructive, high-resolution investigation of battery failure mechanisms, contributing to the enhancement of LIB safety. KW - Tomography KW - X-ray imaging KW - Lithium-ion battery PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611327 DO - https://doi.org/10.1016/j.jpowsour.2024.235472 VL - 623 SP - 1 EP - 10 PB - Elsevier CY - New York, NY AN - OPUS4-61132 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Golusda, L. A1 - Kühl, A. A. A1 - Lehmann, M. A1 - Dahlke, K. A1 - Mueller, S. A1 - Boehm-Sturm, P. A1 - Saatz, Jessica A1 - Traub, Heike A1 - Schnorr, J. A1 - Freise, C. A1 - Taupitz, M. A1 - Biskup, K. A1 - Blanchard, V. A1 - Klein, O. A1 - Sack, I. A1 - Siegmund, B. A1 - Paclik, D. T1 - Visualization of inflammation in experimental colitis by magnetic resonance imaging using very small superparamagnetic iron oxide particles N2 - Inflammatory bowel diseases (IBD) comprise mainly ulcerative colitis (UC) and Crohn´s disease (CD). Both forms present with a chronic inflammation of the (gastro) intestinal tract, which induces excessive changes in the composition of the associated extracellular matrix (ECM). In UC, the inflammation is limited to the colon, whereas it can occur throughout the entire gastrointestinal tract in CD. Tools for early diagnosis of IBD are still very limited and highly invasive and measures for standardized evaluation of structural changes are scarce. To investigate an efficient non-invasive way of diagnosing intestinal inflammation and early changes of the ECM, very small superparamagnetic iron oxide nanoparticles (VSOPs) in magnetic resonance imaging (MRI) were applied in two mouse models of experimental colitis: the dextran sulfate sodium (DSS)-induced colitis and the transfer model of colitis. For further validation of ECM changes and inflammation, tissue sections were analyzed by immunohistochemistry. For in depth ex-vivo investigation of VSOPs localization within the tissue, Europium-doped VSOPs served to visualize the contrast agent by imaging mass cytometry (IMC). VSOPs accumulation in the inflamed colon wall of DSS-induced colitis mice was visualized in T2* weighted MRI scans. Components of the ECM, especially the hyaluronic acid content, were found to influence VSOPs binding. Using IMC, colocalization of VSOPs with macrophages and endothelial cells in colon tissue was shown. In contrast to the DSS model, colonic inflammation could not be visualized with VSOP-enhanced MRI in transfer colitis. VSOPs present a potential contrast agent for contrast-enhanced MRI to detect intestinal inflammation in mice at an early stage and in a less invasive manner depending on hyaluronic acid content. KW - Inflammation KW - Imaging KW - Immunohistochemistry KW - MRI KW - Nanoparticle KW - Extracellular matrix KW - Laser ablation KW - ICP-MS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555395 DO - https://doi.org/10.3389/fphys.2022.862212 SN - 1664-042X VL - 13 IS - July 2022 SP - 1 EP - 15 PB - Frontiers Research Foundation CY - Lausanne AN - OPUS4-55539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kader, A. A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Mangarova, D. B. A1 - Moeckel, J. A1 - Adams, L. C. A1 - Zhao, J. A1 - Saatz, Jessica A1 - Traub, Heike A1 - Buchholz, R. A1 - Karst, U. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Visualization and Quantification of the Extracellular Matrix in Prostate Cancer Using an Elastin Specific Molecular Probe N2 - One of the most commonly diagnosed cancers in men is prostate cancer (PCa). Understanding tumor progression can help diagnose and treat the disease at an early stage. Components of the extracellular matrix (ECM) play a key role in the development and progression of PCa. Elastin is an essential component of the ECM and constantly changes during tumor development. This article visualizes and quantifies elastin in magnetic resonance imaging (MRI) using a small molecule probe. Results were correlated with histological examinations. Using an elastin-specific molecular probe, we were able to make predictions about the cellular structure in relation to elastin and thus draw conclusions about the size of the tumor, with smaller tumors having a higher elastin content than larger tumors. Human prostate cancer (PCa) is a type of malignancy and one of the most frequently diagnosed cancers in men. Elastin is an important component of the extracellular matrix and is involved in the structure and organization of prostate tissue. The present study examined prostate cancer in a xenograft mouse model using an elastin-specific molecular probe for magnetic resonance molecular imaging. Two different tumor sizes (500 mm3 and 1000 mm3) were compared and analyzed by MRI in vivo and histologically and analytically ex vivo. The T1-weighted sequence was used in a clinical 3-T scanner to calculate the relative contrast enhancement before and after probe administration. Our results show that the use of an elastin-specific probe enables better discrimination between tumors and surrounding healthy tissue. Furthermore, specific binding of the probe to elastin fibers was confirmed by histological examination and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Smaller tumors showed significantly higher signal intensity (p > 0.001), which correlates with the higher proportion of elastin fibers in the histological evaluation than in larger tumors. A strong correlation was seen between relative enhancement (RE) and Elastica–van Gieson staining (R2 = 0.88). RE was related to inductively coupled plasma–mass spectrometry data for Gd and showed a correlation (R2 = 0.78). Thus, molecular MRI could become a novel quantitative tool for the early evaluation and detection of PCa. KW - Magnetic resonance imaging KW - MRI KW - Molecular imaging KW - Cancer KW - LA-ICP-MS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538410 DO - https://doi.org/10.3390/biology10111217 VL - 10 IS - 11 SP - 1 EP - 14 PB - MDPI CY - Basel AN - OPUS4-53841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lapenna, M. A1 - Tsamos, Athanasios A1 - Faglion, F. A1 - Fioresi, R. A1 - Zanchetta, F. A1 - Bruno, Giovanni T1 - Vision GNN (ViG) architecture for a fine‑tuned segmentation of a complex Al–Si metal matrix composite XCT volume N2 - In this paper, we implement a vision graph neural network (ViG) architecture to segment microstructures in X-ray computed tomography 3D data. Our ViG architecture is first trained on a synthetic augmented dataset, and then fine-tuned on experimental data to obtain an improved segmentation. Successively, we assess the accuracy of the segmentation on manually-labeled experimental slices. We exemplarily use the approach on a complex microstructure: a metal matrix composite, reinforced with two ceramic phases, intermetallic inclusions and a silicon network, in order to show the generality of our method. ViG model proves to be more efficient than U-Nets in adapting to new data when fine-tuned on a small portion of the experimental data. The fine-tuned ViG shows comparable performance to U-Nets, while largely reducing the number of trainable parameters, with the potential of greater adaptability and efficiency. KW - X-ray Computed tomography KW - Machine Learning KW - Virtual XCT KW - Segmentation KW - Composites PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630593 DO - https://doi.org/10.1007/s10853-025-10834-5 SN - 1573-4803 VL - 60 SP - 6907 EP - 6921 PB - Springer AN - OPUS4-63059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Vogel, Justus A1 - Zhang, F. A1 - Long, N.X. A1 - Nguyen, T.P. T1 - Visibility of Image Quality Indicators (IQI) by Human Observers in Digital Radiography in Dependence on Measured MTFs and Noise Power Spectra N2 - Digital radiographic images were analysed to predict the visibility of image quality indicators (IQI), based on normalized noise power spectra (NNPP) and modulation transfer function (MTF) measurements. The fixed pattern noise of some digital detectors result in different noise spectra, which influence the visibility of different IQIs, depending on the hole diameter. Studies, based on measurement of basic spatial resolution and contrast to noise ratio were performed together with presampled MTF measurements and the NNPS in dependence on the spatial frequency. Plate hole IQIs, step hole IQIs, and equivalent penetrameter sensitivity (EPS) IQIs based on ASTM E 746 were measured to verify the influence of the different parameters. Modelling of digital images was used to verify the applied numeric tools. A study has been performed for imaging plates and digital detector arrays to analyse differences. Formulas for the prediction of the visibility functions for hole type IQIs are derived. In consequence the standards for characterization and classification of computed radiography (ASTM E 2446) and radiography with DDAs (ASTM E 2597) need to be revised. T2 - 12th ECNDT 2018 CY - Gothenburg, Sweden DA - 11.06.2018 KW - Image evaluation KW - Computed radiography (CR) KW - Digital Detector Array (DDA) KW - Detail detection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473486 UR - www.ndt.net/?id=22967 SN - 1435-4934 VL - 23 IS - 8 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-47348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gomes Fernandes, Roger A1 - Al-Mukadam, Raschid A1 - Bornhöft, Hansjörg A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Selle, Susanne A1 - Deubener, Joachim T1 - Viscous Sintering of Acid Leached Glass Powders N2 - The process of viscous flow sintering is a phenomenon that is closely linked to the surface properties of the glass particles. In this work, we studied the extreme case of acid-leaching of soda-lime-silicate glass beads of two different particle size distributions and its effects on non-isothermal viscous sintering of powder compacts. Depth profiling of the chemical composition after leaching revealed a near-surface layer depleted in alkali and alkaline earth ions, associated with concurrent hydration as mass loss was detected by thermogravimetry. Heating microscopy showed that acid treatment of glasses shifted the sinter curves to higher temperatures with increasing leaching time. Modelling of the shrinkage with the cluster model predicted a higher viscosity of the altered surface layer, while analysis of the time scales of mass transport of mobile species (Na+, Ca2+ and H2O) during isochronous sintering revealed that diffusion of Na+ can compensate for concentration gradients before sintering begins. Also, exchanged water species can diffuse out of the altered layer, but the depletion of Ca2+ in the altered surface layer persists during the sinter interval, resulting in a glass with higher viscosity, which causes sintering to slow down. KW - Glass powder KW - Viscous sintering KW - Acid-leaching KW - Sinter retardation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589008 DO - https://doi.org/10.52825/glass-europe.v1i.681 VL - 1 SP - 37 EP - 53 AN - OPUS4-58900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Viscous healing of Vickers indentation–induced cracks in glass N2 - AbstractViscous healing of cracks induced by the Vickers indentation in a soda lime magnesium silicate, a soda borosilicate, and a soda aluminosilicate glass (NAS) was studied by laser scanning microscopy. Plots of the crack length, width, and depth normalized to the initial crack length versus time over viscosity merge into single master curves of each of these quantities for each glass. Despite glass properties do not differ strikingly from each other, however, these master curves strongly differ among the glasses. This finding was attributed to a different interplay of various crack healing phenomena. Lateral cracks were found to be responsible for the bulging of the sample surface around the Vickers imprint, which in turn promotes radial crack widening as the main cause of healing delay. The most rapid healing of lateral cracks was observed in NAS in which bulging and crack widening were least pronounced. KW - Crack healing KW - Glass KW - Vickers indentation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587295 DO - https://doi.org/10.1111/jace.19245 SN - 0002-7820 VL - 106 IS - 10 SP - 5795 EP - 5805 PB - Wiley AN - OPUS4-58729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Viscous crack healing in soda–lime–magnesium–silicate–ZrO2 glass matrix composites N2 - AbstractThe present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content. KW - Crack healing KW - Glass matrix composite KW - Solid oxide fuell cell KW - Vickers identation KW - Viscosity PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607860 DO - https://doi.org/10.1111/jace.20002 SN - 0002-7820 SP - 1 EP - 12 PB - Wiley AN - OPUS4-60786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hufsky, F. A1 - Ibrahim, B. A1 - Beer, M. A1 - Deng, L. A1 - Le Mercier, P. A1 - McMahon, Dino Peter A1 - Palmarini, M. A1 - Thiel, V. A1 - Marz, M. T1 - Virologists—Heroes need weapons N2 - Virologists. You might know a couple of them, but unless you are a virologist yourself, the probability that you have collaborated with one in the past is low. The community is relatively small, but they pack a heavy punch and are expected to play a leading role in the research into pathogens that lies ahead. You may ask why we think virologists are our future. Suffice it to say that it is not just because they have invented technologies that belong to the space age, including use of viruses as vehicles to shuttle genes into cells[1], organic nanoparticles with specific tools attached to their surfaces to get inside target cells[2], and using genetically modified viruses as therapies to fight against cancer[3]. Did you know that virologists currently only know of about 3,200 viral species but that more than 320,000 mammal-associated viruses[4] are thought to await discovery? Just think about the viruses hidden in the Arctic ice[5] or in the insects and other animals from once cut-off regions in the world, which now face ever-increasing human exposure[6]. But a heroic (as well as an apocalyptic) role for virologists may also be on the horizon, as the adoption of phage therapy may, in the future, be used to control harmful bacteria when antibiotics fail KW - Virology KW - Bioinformatics PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442402 DO - https://doi.org/10.1371/journal.ppat.1006771 SN - 1553-7366 SN - 1553-7374 VL - 14 IS - 2 SP - Article e1006771, 1 EP - 3 PB - Public Library of Science CY - Lawrence, Kan. AN - OPUS4-44240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adamus, A. A1 - Ali, I. A1 - Vasileiadis, V. A1 - Al-Hileh, L. A1 - Lisec, Jan A1 - Frank, M. A1 - Seitz, G. A1 - Engel, N. T1 - Vincetoxicum arnottianum modulates motility features and metastatic marker expression in pediatric rhabdomyosarcoma by stabilizing the actin cytoskeleton N2 - Background: Prevention of metastatic invasion is one of the main challenges in the treatment of alveolar rhabdomyosarcoma. Still the therapeutic options are limited. Therefore, an anti-tumor screening was initiated focusing on the anti-metastatic and anti-invasion properties of selected medicinal plant extracts and phytoestrogens, already known to be effective in the prevention and treatment of different cancer entities. Methods: Treatment effects were first evaluated by cell viability, migration, invasion, and colony forming assays on the alveolar rhabdomyosarcoma cell line RH-30 in comparison with healthy primary cells. Results: Initial anti-tumor screenings of all substances analyzed in this study, identified the plant extract of Vincetoxicum arnottianum (VSM) as the most promising candidate, harboring the highest anti-metastatic potential. Those significant anti-motility properties were proven by a reduced ability for migration (60%), invasion (99%) and colony formation (61%) under 48 h exposure to 25 μg/ml VSM. The restricted motility features were due to an induction of the stabilization of the cytoskeleton – actin fibers were 2.5-fold longer and were spanning the entire cell. Decreased proliferation (PCNA, AMT, GCSH) and altered metastasis (e. g. SGPL1, CXCR4, stathmin) marker expression on transcript and protein level confirmed the significant lowered tumorigenicity under VSM treatment. Finally, significant alterations in the cell metabolism were detected for 25 metabolites, with levels of uracil, N-acetyl serine and propanoyl phosphate harboring the greatest alterations. Compared to the conventional therapy with cisplatin, VSM treated cells demonstrated a similar metabolic shutdown of the primary cell metabolism. Primary control cells were not affected by the VSM treatment. Conclusions: This study revealed the VSM root extract as a potential, new migrastatic drug candidate for the putative treatment of pediatric alveolar rhabdomyosarcoma with actin filament stabilizing properties and accompanied by a marginal effect on the vitality of primary cells. KW - Mass Spectroscopy KW - Metabolomics KW - Cancer PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533530 DO - https://doi.org/10.1186/s12906-021-03299-x VL - 21 IS - 1 PB - Springer Nature AN - OPUS4-53353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Christina A1 - Zorn, R. A1 - Emmerling, Franziska A1 - Falkenhagen, Jana A1 - Frick, B. A1 - Huber, P. A1 - Schönhals, Andreas T1 - Vibrational density of states of triphenylene based discotic liquid crystals: dependence on the length of the alkyl chain N2 - The vibrational density of states of a series of homologous triphenylene-based discotic liquid crystals HATn (n = 5, 6, 8, 10, 12) depending on the length of the aliphatic side chain is investigated by means of inelastic neutron scattering. All studied materials have a plastic crystalline phase at low temperatures, followed by a hexagonally ordered liquid crystalline phase at higher temperatures and a quasi isotropic phase at the highest temperatures. The X-ray scattering pattern for the plastic crystalline phase of all materials shows a sharp Bragg reflection corresponding to the intercolumnar distance in the lower q-range and a peak at circa 17 nm-1 related to intracolumnar distances between the cores perpendicular to the columns as well as a broad amorphous halo related to the disordered structure of the methylene groups in the side chains in the higher q-range. The intercolumnar distance increases linearly with increasing chain length for the hexagonal columnar ordered liquid crystalline phase. A similar behaviour is assumed for the plastic crystalline phase. Besides n = 8 all materials under study exhibit a Boson peak. With increasing chain length, the frequency of the Boson peak decreases and its intensity increases. This can be explained by a self-organized confinement model. The peaks for n = 10, 12 are much narrower than for n = 5, 6 which might imply the transformation from a rigid system to a softer one with increasing chain length. Moreover the results can also be discussed in the framework of a transition from an uncorrelated to a correlated disorder with increasing n where n = 8 might be speculatively considered as a transitional state. KW - X-ray scattering KW - Neutron scattering KW - Differential scanning calorimetry PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304789 DO - https://doi.org/10.1039/c3cp55303e SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 16 SP - 7324 EP - 7333 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Hille, Falk A1 - Herrmann, Ralf A1 - Baeßler, Matthias T1 - Vibration-based system identification of a large steel box girder bridge N2 - The Bundesanstalt für Materialforschung und -prüfung (BAM) collaborates with TNO to develop a software framework for automated calibration of structural models based on monitoring data. The ultimate goal is to include such models in the asset management process of engineering structures. As a basis for developing the framework, a multi-span road bridge consisting of ten simply supported steel box girders was selected as a test case. Our group measured output-only vibration data from one box girder under ambient conditions. From the data, we determined eigenfrequencies and mode shapes. In parallel, we developed a preliminary structural model of the box girder for the purpose of predicting its modal properties. In this contribution, we provide an overview of the measurement campaign, the operational modal analysis, the structural modeling and qualitatively compare the identified with the predicted modes. As an outlook, we discuss the further steps in the calibration process and future applications of the calibrated model. T2 - XII International Conference on Structural Dynamics (EURODYN 2023) CY - Delft, The Netherlands DA - 02.07.2023 KW - Verkehrsinfrastukturen KW - SHM KW - Model updating KW - System identification KW - Operational modal analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605041 DO - https://doi.org/10.1088/1742-6596/2647/18/182039 SN - 1742-6596 VL - 2647 IS - 18 SP - 1 EP - 9 PB - IOP Publishing CY - Bristol AN - OPUS4-60504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Luong, Thi Mai Hoa A1 - Zabel, V. A1 - Lorenz, W., A1 - Rohrmann, R.G., T1 - Vibration-based model updating and identification of multiple axial forces in truss structures N2 - Safety assessment of existing iron and steel truss structures requires the determination of the axial Forces and corresponding stresses in truss structural members. The results of the axial force determination can be integrated as part of a structural health Monitoring scheme for existing trusses. In this work, a methodology is proposed to identify multiple axial forces in members of a truss structure based on the modal parameters. Vibration test allows the identification of the natural frequencies and mode shapes, globally of the truss structure as well as locally of the individual bars. The method calibrates the numerical model of the truss structure using a genetic algorithm and strategic validation criteria. The validation criteria are based on the identified natural frequencies and global mode shapes of the truss structure as well as information of the axial forces in the individual bars of the truss, which are estimated from the natural frequencies and five amplitudes of the corresponding local mode shapes of the single bars based on an analytical-based algorithm. The calibration allows the identification of the axial forces in all bars of the truss structure. For mode pairing strategy, a technique makes use of the enhanced modal assurance criteria with the calculation of the modal strain energies. Moreover, the modal strain energies are also used to select the relevant local mode shape of the individual bars. The feasibility and accuracy of the proposed methodology is verified by laboratory experiments on several truss structures. In situ tests on existing trusses are intended. The results from one of the laboratory tested structures, i.e. a two-bar system, are included in this paper. KW - Truss structures KW - Axial force KW - Dynamic test KW - Model updating KW - Optimization technique PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402263 DO - https://doi.org/10.1016/j.proeng.2017.04.499 SN - 1877-7058 VL - 188 SP - 385 EP - 392 PB - Elsevier AN - OPUS4-40226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf A1 - Moortgat-Pick, A. A1 - Marx, S. ED - Helmerich, Rosemarie ED - Ilki, A. ED - Motavalli, M. T1 - Vibration Analysis of Structures using a Drone (UAV) based Mobile Sensing Platform N2 - The identification of the dynamic behavior of structures, like bridges and towers, is relevant to address multiple issues. In many cases the dynamic parameters should be acquired only once or at a frequency that doesn’t justify the installation of distinct vibration sensors for a long-term monitoring. To identify modal frequencies of a structure, a drone based mobile sensing platform has been implemented. This sensing platform measures the relative displacement be-tween the structure and the drone, which also shows a strong dynamic behavior under wind tur-bulences. By regarding the dynamic model of the drone and additional measurements at the dis-tance sensor the absolute movement of the structure can be estimated based on the measured relative distance. This time domain data is a suitable input for various operational modal analysis algorithms. The system has been used to identify the dynamic properties of test and real structure, like a 1.5 MW wind turbine tower. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) CY - Potsdam, Germany DA - 27.08.2019 KW - Modal Analysis KW - Drone KW - Vibration KW - Wind Turbines KW - Bridges PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492045 UR - http://data.smar-conferences.org/downloads/SMAR_2019_Proceedings.zip SN - 978-3-947971-07-7 SP - We.4.C.3 EP - 8 PB - German Society for Non-Destructive Testing (DGZfP e.V.) AN - OPUS4-49204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taabache, Soraya A1 - Bertin, Annabelle T1 - Vesicles from amphiphilic dumbbells and Janus dendrimers: bioinspired self-assembled structures for biomedical applications N2 - The current review focuses on vesicles obtained from the self-assembly of two types of dendritic macromolecules, namely amphiphilic Janus dendrimers (forming dendrimersomes) and amphiphilic dumbbells. In the first part, we will present some synthetic strategies and the various building blocks that can be used to obtain dendritic-based macromolecules, thereby showing their structural versatility. We put our focus on amphiphilic Janus dendrimers and amphiphilic dumbbells that form vesicles in water but we also encompass vesicles formed thereof in organic solvents. The second part of this review deals with the production methods of these vesicles at the nanoscale but also at the microscale. Furthermore, the influence of various parameters (intrinsic to the amphiphilic JD and extrinsic—from the environment) on the type of vesicle formed will be discussed. In the third part, we will review the numerous biomedical applications of these vesicles of nano- or micron-size. KW - Janus dendrimers KW - Amphiphilic dumbbells KW - Self-assembled structures KW - Dendrimersomes KW - Artificial cells PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418245 DO - https://doi.org/10.3390/polym9070280 SN - 2073-4360 VL - 9 IS - 7 SP - Article 280, 1 EP - 36 AN - OPUS4-41824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosenkranz, D. A1 - Kriegel, F. L. A1 - Mavrakis, E. A1 - Pergantis, S. A. A1 - Reichardt, P. A1 - Tentschert, J. A1 - Jakubowski, N. A1 - Laux, P. A1 - Panne, Ulrich A1 - Luch, A. T1 - Versatile dual-inlet sample introduction system for multi-mode single particle inductively coupled plasma mass spectrometry N2 - Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number concentration by using the single-particle mode of the instrument (spICP-MS). The accuracy of measurement depends on the setup, operational conditions of the instrument and specific parameters that are set by the user. The transport efficiency of the ICP-MS is crucial for the quantification of the NP and usually requires a reference material with homogenous size distribution and a known particle number concentration. Currently, NP reference materials are available for only a few metals and in limited sizes. If particles are characterized without a reference standard, the results of both size and particle number may be biased. Therefore, a dual-inlet Setup for characterizing nanoparticles with spICP-MS was developed to overcome this problem. This setup is based on a conventional introduction system consisting of a pneumatic nebulizer (PN) for nanoparticle solutions and a microdroplet Generator (μDG) for ionic calibration solutions. A new and flexible interface was developed to facilitate the coupling of μDG, PN and the ICP-MS system. The interface consists of available laboratory components and allows for the calibration, nanoparticle (NP) characterization and cleaning of the arrangement, while the ICP-MS instrument is still running. Three independent analysis modes are available for determining particle size and number concentration. Each mode is based on a different calibration principle. While mode I (counting) and mode III (μDG) are known from the literature, mode II (sensitivity), is used to determine the transport efficiency by inorganic ionic Standard solutions only. It is independent of NP reference materials. The μDG based inlet system described here guarantees superior analyte sensitivities and, therefore, lower detection limits (LOD). The size dependent LODs achieved are less than 15 nm for all NP (Au, Ag, CeO2) investigated. KW - Spectrometer KW - Reference KW - Calibration PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536121 DO - https://doi.org/10.3791/61653 SN - 1940-087X IS - 163 SP - 1 EP - 19 PB - MyJoVE Corporation CY - Cambridge, MA, USA AN - OPUS4-53612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Vehicle-track-soil interaction and train-induced ground vibration – Theory and measurements in Germany, Switzerland and France N2 - Three measurement campaigns of train-induced ground vibrations are evaluated for the vehicle-track-soil interaction. Ground vibrations, track vibrations and vehicle vibrations have been measured for train passages and impulse excitation and compared with theoretical results. The soil and the track-soil system are calculated by wavenumber integrals. The influence of the vehicle is introduced by a substructure method. By comparing theory and measurement the different components of excitation force and ground vibration can be analysed, the quasi-static excitation, track-alignment errors, the out-of-roundness of wheels, the wheel and rail roughness, and moreover, scattered axle impulses and ineffective high-frequency parts of the wheelset accelerations and forces. KW - Vehicle-track-soil interaction KW - Train-induced ground vibration KW - Measurement campaigns KW - Wavenumber integrals KW - Components of excitation KW - Wheelset accelerations PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486702 DO - https://doi.org/10.1088/1742-6596/1264/1/012034 SN - 1742-6596 SN - 1742-6588 VL - 1264 SP - Artikel 012034-1 EP - 12 PB - IOP Publishing Ltd AN - OPUS4-48670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Vehicle Dynamics and Train‑Induced Ground Vibration—Theoretical Analyses and Simultaneous Vehicle, Track, and Soil Measurements N2 - Ground vibrations near railway lines are generated by the forces that are acting between wheel and rail. It seems to be a straight forward assumption that the vehicle dynamics are important for the level and the frequencies of the excitation forces. Different vehicle dynamics phenomena are analysed for their role in the excitation of ground vibrations: rigid body modes of the bogies, elastic (bending) modes of the car body, and elastic modes of the wheelset. The theoretical analyses use rigid body models, simplified elastic models, and detailed elastic models. Some of these problems are vehicle–track interaction problems where 3D finite‑element boundary‑element models have been used for the track and soil. It is shown that the rigid or flexible vehicle modes are well in the frequency range of ground vibrations (4 to 100 Hz). They have an influence on the excitation force but the additional forces are rather small and can be neglected in ground vibration prediction. The theoretical results are checked by experimental results of a simultaneous measurement of vehicle, track, and ground vibrations. KW - Rigid vehicle model KW - Flexible car body KW - Flexible wheelset KW - Dynamic loads KW - Ground vibration PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569796 DO - https://doi.org/10.3390/vehicles5010013 VL - 5 IS - 1 SP - 223 EP - 247 PB - MDPI CY - Basel AN - OPUS4-56979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sichler, Theresa Constanze A1 - Adam, Christian A1 - Barjenbruch, M. A1 - Montag, D. A1 - Mauch, Tatjana A1 - Sommerfeld, Thomas A1 - Ehm, J.H. T1 - Variation of the element composition of municipal sewage sludges in the context of new regulations on phosphorus recovery in Germany N2 - Phosphorus (P) recovery is obligatory for all sewage sludges with more than 20 g P/kg dry matter (DM) from 2029 in Germany. Nine wastewater treatment plants (WWTPs) were chosen to investigate variations of phosphorus contents and other parameters in sewage sludge over the year. Monthly sewage sludge samples from each WWTP were analyzed for phosphorus and other matrix elements (C, N, H, Ca, Fe, Al, etc.), for several trace elements (As, Cr, Mo, Ni, Pb, Sn) and loss of ignition. Among the nine WWTPs, there are four which have phosphorus contents both above and below the recovery limit of 20 g/kg DM along the year. Considering the average phosphorus content over the year, only one of them is below the limit. Compared to other matrix elements and parameters, phosphorus fuctuations are low with an average of 7% over all nine WWTPs. In total, only hydrogen and carbon are more constant in the sludge. In several WWTPs with chemical phosphorus elimination, phosphorus fuctuations showed similar courses like iron and/or aluminum. WWTPs with chamber flter presses rather showed dilution efects of calcium dosage. As result of this study, monthly phosphorus measurement is highly recommended to determine whether a WWTP is below the 20 g/kg DM limit. KW - Sewage sludge KW - Phosphorus recovery KW - Wastewater KW - Phosphorus elimination PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557499 DO - https://doi.org/10.1186/s12302-022-00658-4 SN - 2190-4707 VL - 34 IS - 1 SP - 1 EP - 12 PB - Springer Nature CY - Berlin AN - OPUS4-55749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Opitz, R. A1 - Ghoreishi, N. A1 - Plate, K. A1 - Barnes, J.-P. A1 - Bellew, A. A1 - Bellu, A. A1 - Ceccone, G. A1 - de Vito, E. A1 - Delcorte, A. A1 - Franquet, A. A1 - Fumageli, F. A1 - Gilliland, D. A1 - Jungnickel, H. A1 - Lee, T.G. A1 - Poleunis, C. A1 - Rading, D. A1 - Shon, H.K. A1 - Spampinato, V. A1 - Son, J.G. A1 - Wang, F. A1 - Wang, Y.-C. A. A1 - Zhao, Y. A1 - Roloff, A. A1 - Tentschert, J. A1 - Radnik, Jörg T1 - VAMAS TWA2 interlaboratory comparison: Surface analysis of TiO2 nanoparticles using ToF-SIMS N2 - Due to the extremely high specific surface area of nanoparticles and corresponding potential for adsorption, the results of surface analysis can be highly dependent on the history of the particles, particularly regarding sample preparation and storage. The sample preparation method has, therefore, the potential to have a significant influence on the results. This report describes an interlaboratory comparison (ILC) with the aim of assessing which sample preparation methods for ToF-SIMS analysis of nanoparticles provided the most intra- and interlaboratory consistency and the least amount of sample contamination. The BAM reference material BAM-P110 (TiO2 nanoparticles with a mean Feret diameter of 19 nm) was used as a sample representing typical nanoparticles. A total of 11 participants returned ToF-SIMS data,in positive and (optionally) negative polarity, using sample preparation methods of “stick-and-go” as well as optionally “drop-dry” and “spin-coat.” The results showed that the largest sources of variation within the entire data set were caused by adventitious hydrocarbon contamination or insufficient sample coverage, with the spin-coating protocol applied in this ILC showing a tendency toward insufficient sample coverage; the sample preparation method or the participant had a lesser influence on results. KW - Secondary Ion Mass Spectrometry KW - VMAAS KW - Titania KW - Interlaboratory comparison KW - Reproducibility PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582290 DO - https://doi.org/10.1116/6.0002814 SN - 0734-2101 VL - 41 IS - 5 SP - 053210-1 EP - 053210-13 PB - AIP (American Institute of Physics) AN - OPUS4-58229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Costa, Giancarlo A1 - Thöns, Sebastian A1 - Limongelli, Maria Pina A1 - Piscini, Andrea T1 - Value of information‐driven innovation in Gerber saddles monitoring N2 - AbstractInnovation plays a crucial role in shaping technological, economic, and social progress in modern societies. In the realm of bridge integrity management, the development and diffusion of technologies to acquire information can significantly enhance industries' safety and functionality capabilities. Among the most widely diffused bridge types in Europe and North America, Gerber bridges are particularly susceptible to deterioration over time. Gerber saddles are typically not instrumented and are checked only through visual inspections. This paper introduces the metric of the Value of Information for Innovation to estimate the benefit associated with introducing an established technology in a new market of application. Herein, the operational value of implementing microelectromechanical inclinometers in the integrity management of Gerber saddles is quantified for the specific case of a bridge in northern Italy. Microelectromechanical systems companies may use these results to optimally select the technology price, investigate diverse market strategies, and optimize sensor arrangement. KW - Gerber saddles KW - Innovation KW - MEMs KW - Sensor optimization KW - Value of Information PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627853 DO - https://doi.org/10.1002/suco.202400951 SN - 1751-7648 VL - 674 SP - 230 EP - 240 PB - Wiley AN - OPUS4-62785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Jan A1 - Häfner, P. A1 - Reimann, H.-A. A1 - Schartel, Bernhard T1 - Valorization of Natural Fibers in Flame Retarded Poly(lactic acid) N2 - Extensive research has explored natural fiber reinforced composites, typically focusing on a single fiber within a polymer matrix. Comprehensive comparisons across different natural fibers in the same polymer, which are critical for industrial material selection, remain limited. This work presents a systematic comparison of untreated hemp, flax, and sisal fibers incorporated at varying fiber lengths and loadings into flame retarded poly(lactic acid) (PLA). Fire behavior, thermal, and mechanical responses were investigated through thermogravimetry, UL 94, and cone calorimetry, alongside crystallinity, molecular weight (MW), and microstructural analysis. Fiber incorporation reduced the peak heat release rate (pHRR) by up to 30 % in 30 wt% hemp, attributed to protective layer formation, but increased flammability in UL 94. A phytic acid melamine salt combined with expandable graphite and 20 wt% hemp produced incomplete combustion at 50 kW/m², raising char residue from 4 to 24 wt% and halving pHRR. Petrella plots revealed that fiber addition alone lowered fire load and flashover propensity as effectively as phytic acid melamine; with hemp, phytic acid and expendable graphite, the flashover hazard and fire load were halved. MW was preserved while crystallinity and modulus increased with fiber content. Hemp delivered the most consistent reinforcement, while optimized processing enabled flax and sisal to improve stiffness. Performance gains were strongest when individual fibers were dispersed via optimized processing, preventing bundle fracture under load. Plasma modification of the fibers improved the maximum tensile strength in the composites. A practical guide is provided for valorizing natural fibers in PLA composites, demonstrating routes to bio-based, compostable materials with improved fire safety and mechanical performance suitable for industrial processing. KW - Poly(lactic acid) KW - Hemp KW - Sisal KW - Flax KW - Flame retardant KW - Phytic acid PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653038 DO - https://doi.org/10.1016/j.mtcomm.2025.114575 SN - 2352-4928 VL - 50 SP - 1 EP - 41 PB - Elsevier Ltd. AN - OPUS4-65303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Kern, Simon A1 - Guhl, Svetlana A1 - Meyer, Klas A1 - Maiwald, Michael ED - Maiwald, Michael T1 - Validation report on NMR N2 - The departure from the current automation landscape to next generation automation concepts for the process industry has already begun. Smart functions of sensors simplify their use and enable plug and play integration, even though they may appear to be more complex at first sight. Smart sensors enable concepts like self-diagnostics, self-calibration, and self-configuration/ parameterization whenever our current automation landscape allows it. Here we summarize the currently discussed general requirements for process sensors 4.0 and introduce a smart online NMR sensor module as example, which was developed for an intensified industrial process funded by the EU’s Horizon 2020 research and innovation programme (www.consensspire.eu). KW - Process Monitoring KW - Online NMR Spectroscopy KW - Indirect Hard Modeling KW - Process Control KW - Process Analytical Technology KW - CONSENS PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435521 SP - 1 EP - 31 AN - OPUS4-43552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prabhakara, Prathik A1 - Mielentz, Frank A1 - Stolpe, Heiko A1 - Behrens, Matthias A1 - Lay, Vera A1 - Niederleithinger, Ernst T1 - Validation of novel ultrasonic phased array borehole probe by using simulation and measurement N2 - Low-frequency ultrasonic testing is a well-established non-destructive testing (NDT) method in civil engineering for material characterization and the localization of cracks, reinforcing bars and delamination. A novel ultrasonic borehole probe is developed for in situ quality assurance of sealing structures in radioactive waste repositories using existing research boreholes. The aim is to examine the sealing structures made of salt concrete for any possible cracks and delamination and to localize built-in components. A prototype has been developed using 12 individual horizontal dry point contact (DPC) shear wave transducers separated by equidistant transmitter/receiver arrays. The probe is equipped with a commercially available portable ultrasonic flaw detector used in the NDT civil engineering industry. To increase the sound pressure generated, the number of transducers in the novel probe is increased to 32 transducers. In addition, the timed excitation of each transducer directs a focused beam of sound to a specific angle and distance based on the previously calculated delay time. This narrows the sensitivity of test volume and improves the signal-to-noise ratio of the received signals. In this paper, the newly designed phased array borehole probe is validated by beam computation in the CIVA software and experimental investigations on a half-cylindrical test specimen to investigate the directional characteristics. In combination with geophysical reconstruction methods, it is expected that an optimised radiation pattern of the probe will improve the signal quality and thus increase the reliability of the imaging results. This is an important consideration for the construction of safe sealing structures for the safe disposal of radioactive or toxic waste. KW - Ultrasound KW - Phased array KW - Concrete KW - Borehole PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565722 DO - https://doi.org/10.3390/s22249823 SN - 1424-8220 VL - 22 IS - 24 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-56572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kalbe, Ute A1 - Lehnik-Habrink, Petra A1 - Bandow, Nicole A1 - Sauer, Andreas T1 - Validation of European horizontal methods for the analysis of PAH, PCB and dioxins in sludge, treated biowaste and soil N2 - Draft standards for the determination of organic pollutants in the solid matter of environmental matrices such as sludge, treated biowaste and soil have been basically developed in the framework of the European standardization project HORIZONTAL. A research project financed by the German Federal Environment Agency was initiated to finalize some of these CEN standard drafts, since fully validated standard procedures are crucial for the evaluation of their reliability in the context of implementation in legislation on environmental health. Approach: Appropriate test materials (< 2mm particle size) were prepared and homogenized from contaminated soils, sludge and treated biowaste containing polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dioxins, furans and dioxin-like-PCB and served, along with reference solutions, as the basis for international interlaboratory comparisons. Performance data of three analytical standard procedures were obtained by the statistical evaluation of results received from 11 to 29 participants per test material. Results: The overall variation coefficients of reproducibility (between-lab standard deviations) for the sum parameters were roughly between 10 and 35 %. The variation coefficients of repeatability (within-lab standard deviations) range between 3 % and 8 % and show no trend considering the substance groups or matrices. The highest coefficients of reproducibility were found for the analysis of PAHs, which were between 26 and 35 %, depending on the matrix, whereas 7-17 % reproducibility was observed for toxicity equivalents (TEQ) comprising dioxins, furans and dl-PCB. Conclusions: Overall, the results confirm that the procedures described in the Technical Specifications are fit for purpose for all three matrices and that the feasibility of the HORIZONTAL approach, to cover several matrices with one standard per analyte, was thereby proven. KW - Standardization KW - Analytical methods KW - Organic contaminants KW - Validation trial KW - Interlaboratory comparison PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479914 DO - https://doi.org/10.1186/s12302-019-0211-3 SN - 2190-4715 VL - 31 SP - 29, 1 EP - 10 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-47991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maack, Stefan A1 - Villalobos, S. A1 - Scott, D. T1 - Validation of artificial defects for non-destructive testing measurements on a reference structure N2 - Non-destructive testing was established over the last decades as an important tool for assessing damages, material characterization and quality assurance in civil engineering. For example, Ground Penetrating Radar (GPR) can be used to scan large areas of concrete structures to determine the spatial position of the reinforcement. With the ultrasonic echo method, the thickness of concrete structures can be easily determined even if a high density of reinforcement is given. Various methods and processes have been developed for the validation of NDT procedures aiming at ensuring the quality of measurements in practical use. The Probability of Detection (POD) for example, is an available method to compare different technical devices with each other quantitatively regarding their performance. With this method, the best suited testing device for a specific inspection task under defined boundary conditions can be selected. By using the Guide to the Expression of Uncertainty in Measurement (GUM), it is possible to quantify the measurement uncertainty of an inspection procedure for a specific task. Another important aspect to improve the acceptance of Non-destructive testing methods is the development of reference specimens. Reference specimens serve for the calibration and further development of NDT methods under realistic conditions in different laboratories under the same conditions. A particular challenge here is the most realistic representation of a damage that can occur at building sites. Possible damages include for example horizontal and vertical cracks or honeycombs in concrete. Such a reference structure was built for the development of a new design of power plant constructions. Comparative studies on the manufacturing of realistic honeycombs and delaminations were carried out in advance on a test specimen. The results of this study are presented here. T2 - ICCRRR 2018 - Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 19.11.2018 KW - Zerstörungsfreie Prüfung KW - Nondestructive testing KW - Istzustandserfassung KW - Ultrasonic PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464497 DO - https://doi.org/10.1051/matecconf/201819906006 SN - 2261-236X VL - 199 SP - 1 EP - 9 PB - EDP Sciences CY - Les Ulis AN - OPUS4-46449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram A1 - Wossidlo, Peter T1 - Validation of a low blow specimen technique for R-curve determination using a drop tower N2 - Fracture mechanics based component design requires appropriate fracture mechanics toughness data with respect to both, loading rate as well as test temperature. Taking high-rate loading into account such as with accidental scenarios, different standards such as ASTM E 1820 or BS 7448-3 provide some information on dynamic fracture mechanics testing. Nevertheless, the designations differ so that a validation of the own material specific test method used for dynamic R-curve determination is mandatory. In order to address this for ductile cast iron materials an experimental method for the reliable determination of dynamic J-integral crack resistance curves at -40 °C following the multiple specimen approach has been established and validated. The experimental concept offers some additional valuable features. Single values of dynamic crack initiation toughness can be determined using a single specimen technique based on crack sensors. Furthermore, an experimentally independent method is provided according to which CTOD δ5 R-curves can be established. The focus of the present paper is on the validation of the experimental low blow technique using a drop tower test system. A drop tower test system was developed and set up to perform low blow tests at temperatures down to -40 °C. The system allows for a variation of the impact mass and height and was optimized for testing of ductile cast iron at stress intensity rates from approximately 5∙10⁴ to 3∙10⁵ MPa√ms⁻¹. This range of loading rate is characteristic for instance with crash scenarios of heavy sectioned DCI casks for radioactive materials. In order to address characteristic challenges of impact tests (test duration of microseconds up to milliseconds, inertial effects, signal oscillations), an appropriate full bridge strain gage method for the measurement of force directly on the specimen as well as a non-contact measurement of load line displacement using an optical extensometer have been developed and validated. The low blow test requires either to prevent bouncing strikes of the hammer by using the stop block technique or to catch the hammer after its first strike. Both options are not part of the experimental concept and setup which have been realized here. The paper describes investigations which have been performed in order to make sure that bouncing strikes of the hammer do not cause additional crack extension in the specimen. This is necessary to ensure a unique relation between the work done and the achieved crack extension. The investigations covered the analysis of limit loads of the specimen with respect to the measured force. The measured stiffness of the specimen was assessed and signals of crack sensors were analyzed. Furthermore, an analysis of the mechanical behavior of the loading system and the specimen by optical observation was performed. Corresponding results are discussed in the paper. It had finally been proven that additional crack extension in the specimen due to bouncing strikes of the hammer is not to be expected under the given conditions of test setup, material and loading. It can be seen as a major experimental advantage that the striker does not have to be catched after the low blow test. T2 - XXIV Italian Group of Fracture Conference CY - Urbino, Italy DA - 01.03.2017 KW - Dynamic fracture mechanics KW - R-curve KW - Low blow KW - Ductile cast iron PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437686 DO - https://doi.org/10.1016/j.prostr.2017.04.005 SN - 2452-3216 VL - 3 SP - 25 EP - 32 AN - OPUS4-43768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neuschaefer-Rube, U. A1 - Illemann, J. A1 - Sturm, M. A1 - Bircher, B. A1 - Meli, F. A1 - Bellon, Carsten A1 - Evsevleev, Sergei T1 - Validation of a fast and traceable radiographic scale calibration of dimensional computed tomography N2 - A fast and highly precise method of determining the geometrical scale factor of computed tomography (CT) measurements has been validated successfully by Bundesanstalt für Materialforschung und -prüfung (BAM), the Federal Institute of Metrology (METAS) and Physikalisch-Technische Bundesanstalt (PTB) within the scope of AdvanCT (Advanced Computed Tomography for dimensional and surface measurements in industry), a project funded in the European Metrology Programme for Innovation and Research (EMPIR). The method has been developed by PTB and requires only two radiographic images of a calibrated thin 2D standard (hole grid standard) from two opposite directions. The mean grid distance is determined from both radiographs. From this and with the help of the calibration result, the radiographic scale and therefore the voxel size is determined. The procedure takes only a few minutes and avoids a time-consuming CT scan. To validate the method, the voxel sizes determined via this method were compared with voxel sizes determined from CT scans of calibrated objects. Relative deviations between the voxel sizes in the range of 10−5 were achieved with minimal effort using cone-beam CT systems at moderate magnifications. KW - Dimensional metrology KW - Voxel size KW - Industrial CT KW - Geometrical magnification PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553271 DO - https://doi.org/10.1088/1361-6501/ac74a3 SN - 0957-0233 VL - 33 IS - 9 SP - 1 EP - 9 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-55327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hanelt, Sven A1 - Friedrich, Jörg Florian A1 - Meyer-Plath, Asmus T1 - UV spectrometric indirect analysis of brominated MWCNTs with UV active thiols and an alkene-reaction kinetics, quantification and differentiation of adsorbed bromine and oxygen N2 - Indirect UV-absorption spectrometry was shown to be a valuable tool for chemical characterization of functionalized carbon nanotubes (CNTs). It complements data from X-ray photoelectron spectroscopy (XPS) or FTIR analysis since it helps to clarify the type and concentration of functional groups. The principles of indirect application of UV-spectrometry and its mathematical interpretation are discussed. Their facile application, together with their adequate sensitivity and high flexibility, make UV-absorption-based approaches a valuable alternative to fluorescence spectrometry. Here, the approach was applied to the chemical analysis of oxidizing substances on CNTs. For this, pristine CNTs of low but finite oxygen content as well as brominated CNTs were analyzed by reaction in suspension with UV-active thiol reagents and a styrene derivative. It was shown that carefully selected reagents allow differentiation and quantification of bromine and generally oxidizing entities like oxygen. For brominated CNTs, it was shown that physisorbed bromine may dominate the overall bromine content. KW - Carbon nanotubes KW - CNTs KW - UV-spectrometry KW - Bromination KW - Thiols KW - Mercaptans KW - Disulfides KW - Quantification KW - Kinetics PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289077 DO - https://doi.org/10.3390/ma6083035 SN - 1996-1944 VL - 6 IS - 8 SP - 3035 EP - 3063 PB - MDPI CY - Basel AN - OPUS4-28907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baláž, Matej A1 - Birinci, Mustafa A1 - Şentürk, Kader A1 - Achimovičová, Marcela A1 - Baláž, Peter A1 - Tampubolon, Imelda Octa A1 - Stolar, Tomislav A1 - Bienert, Ralf A1 - Emmerling, Franziska A1 - Erdemoğlu, Sema A1 - Sis, Hikmet A1 - Erdemoğlu, Murat T1 - Utilizing Taguchi method and in situ X-ray powder diffraction monitoring to determine the influence of mechanical activation conditions on the physico-chemical properties and Al leachability of K-feldspar N2 - K-feldspar represents an important natural resource of potassium and aluminum. Within the framework of this study, the K-feldspar was mechanically activated in a planetary ball mill under different conditions planned according to 43 Taguchi orthogonal array experimental design. As outputs, specific surface area (SBET), median particle size (d50), amorphization degree of mineral phases , and Al recovery were used. It was found that the initial d50 value of 293 μm could be reduced to 6.7 μm and the SBET value of 4.7 m2/g could be increased up to 32.5 m2/g upon milling. Both microcline KAl3SiO8, and albite NaAl3SiO8 could be almost completely amorphized, whereas quartz SiO2 still maintained some crystallinity even under the most intensive conditions. Increasing SBET and decreasing the d50 values did not lead to a significant improvement in Al leach recovery, whereas a clear relationship between the amorphization of microcline and the recovered aluminum was found. Analysis of Variance (ANOVA) showed that increasing ball-to-powder ratio is the most beneficial for the improvement in Al recovery. In situ powder X-ray diffraction monitoring performed in an oscillation ball mill under synchrotron irradiation has shown very rapid amorphization of microcline phase at the beginning. However, amorphization of microcline was only partial after two hours of the treatment in this mill, apart from almost complete process in the planetary ball mill. In the end, regressions for the calculation of Al recovery by knowing the values of input parameters were calculated. In general, by just using mechanical activation without the subsequent roasting process that is commonly used to boost metal recoveries, it was possible to quantitatively recover aluminum from K-feldspar. KW - Mechanochemistry KW - Mechanical activation KW - Design of experiments PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611059 DO - https://doi.org/10.1016/j.jmrt.2024.08.156 SN - 2238-7854 VL - 32 SP - 3886 EP - 3895 PB - Elsevier B.V. AN - OPUS4-61105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauli, Jutta A1 - Ramírez, A. A1 - Crasselt, C. A1 - Schmidt, W. A1 - Resch-Genger, Ute T1 - Utilizing optical spectroscopy and 2',7'-difluorofluorescein to characterize the early stages of cement hydration N2 - The increasingly sophisticated nature of modern, more environmentally friendly cementitious binders requires a better understanding and control particularly of the complex, dynamic processes involved in the early phase of cement hydration. In-situ monitoring of properties of a constantly changing system over a defined period of time calls for simple, sensitive, fast, and preferably also non-invasive methods like optical spectroscopy KW - Flourescence KW - Optical probe KW - Sensor KW - Dye KW - Flourescin KW - Photophysics KW - PH KW - Quantum yield KW - Quality assurance KW - Mechanism KW - Cement KW - Concrete KW - Building material KW - Hydration KW - Process monitoring PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537176 DO - https://doi.org/10.1088/2050-6120/ac2da0 SN - 2050-6120 VL - 10 IS - 1 SP - 2 EP - 13 PB - IOP Science AN - OPUS4-53717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Long, Lijia A1 - Alcover, I. F. A1 - Thöns, Sebastian T1 - Utility analysis for SHM durations and service life extension of welds on steel bridge deck N2 - Optimization of the duration of Structural Health Monitoring (SHM) campaigns is rarely performed. This article provides a utility-based solution to posteriorly determine: i) optimal monitoring Durations and ii) the extension of the service life of the welds on a steel bridge deck. The approach is Illustrated with a case study focusing on remaining fatigue life estimation of the welds on the orthotropic steel deck of the Great Belt Bridge, in Denmark. The identification of the optimal monitoring duration and the decision about extending the service life of the welds are modelled by maximizing the expected benefits and minimizing the structural risks. The results are a parametric analysis, mainly on the effect of the target probability, benefit, cost of failure, cost of rehabilitation, cost of monitoring and Discount rate on the posterior utilities of monitoring strategies and the choice of service life considering the risk variability and the costs and benefits models. The results show that the decision on short-term monitoring, i.e., 1 week every six months, is overall the most valued SHM strategy. In addition, it is found that the target probability is the most sensitive parameter affecting the optimal SHM Durations and service life extension of the welds. KW - Fatigue KW - Monitoring strategy KW - Orthotropic steel deck KW - Structural health monitoring KW - Utility and decision theory PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521719 DO - https://doi.org/10.1080/15732479.2020.1866026 SN - 1573-2479 VL - 18 IS - 4 SP - 492 EP - 504 PB - Taylor Francis Online AN - OPUS4-52171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Vinzenz A1 - Fasselt, Janek Maria A1 - Kruse, Tobias A1 - Klötzer, Christian A1 - Kleba-Ehrhardt, Rafael A1 - Choma, Tomasz A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Using ultrasonic atomization to recycle aluminium bronze chips for additive laser directed energy deposition N2 - Abstract In the post-processing of large maritime components, a considerable amount of waste in the form of milling and grinding chips is produced. At the same time, additive manufacturing technologies have shown great potential in producing high-volume parts for maritime applications, allowing novel design approaches and short lead times. In this context, this study presents a sustainable approach to recycle and use aluminium bronze waste material, generated during post-processing of large cast ship propellers, as feedstock for laser-powder directed energy deposition. The recycling technology used to produce powder batches is inductive re-melting in combination with ultrasonic atomization. The derived metal powders are characterized using digital image analysis, powder flowability tests, scanning electron microscopy as well as energy dispersive X-ray spectroscopy. Compared to conventional metal powders produced by gas atomization, the recycled material shows excellent sphericity and a powder size distribution with a higher content of finer and coarser particles. Metallographic sections of deposited additively produced specimens show an increased hardness and reduced ductility, but also competitive densities and higher yield and ultimate tensile strength compared to cast material. The process chain shows high potential for the maritime sector to enable circular and sustainable manufacturing. KW - Industrial and Manufacturing Engineering PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594444 DO - https://doi.org/10.1088/1757-899X/1296/1/012036 VL - 1296 IS - 1 SP - 1 EP - 11 PB - IOP Publishing AN - OPUS4-59444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rabe, U. A1 - Pudovikov, S. A1 - Herrmann, H.-G. A1 - Wiggenhauser, H. A1 - Prabhakara, Prathik A1 - Niederleithinger, Ernst T1 - Using the Corner Reflection for Depth Evaluation of Surface Breaking Cracks in Concrete by Ultrasound N2 - The corner echo is a well-known effect in ultrasonic testing, which allows detection of surface breaking cracks with predominantly perpendicular orientation to the surface as, for example, corrosion cracks in metal pipes or shafts. This echo is formed by two planes, the surface of the crack and the surface which the crack breaks. It can also be classified as a half-skip method, since a reflection of the pulse occurs on the backwall before the reflection at the defect takes place. In combination with the diffraction from the crack tip, the corner echo also allows crack sizing. As shown in this paper, the corner reflection can be used in civil engineering for nondestructive inspection of concrete. Commercially available low frequency ultrasonic arrays with dry point contact sources generate SH transversal waves with sufficient divergence of the sound field in order to detect corner reflections. Ultrasonic line-scans and area-scans were acquired with a linear array on flat concrete specimens, and the data were reconstructed by the Synthetic aperture focusing technique. If the angles and the area of reconstruction are chosen accordingly, the corner echo reflection can be distinguished from other ultrasonic information. The corner echo can thus be used as a method for deciding whether a crack is a partial-depth crack or a full-depth crack and thus for obtaining a statement about crack depth. This paper presents corresponding experimental results obtained on concrete specimens with artificial test defects and cracks induced under controlled conditions. KW - Ultrasound KW - Crack depth KW - Concrete KW - Corner echo PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574631 DO - https://doi.org/10.1007/s10921-023-00956-8 SN - 0195-9298 VL - 42 IS - 2 SP - 1 EP - 19 PB - Springer Nature AN - OPUS4-57463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Schneider, J. A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - Using SXRR to Probe the Nature of Discontinuities in SLM Additive Manufactured Inconel 718 Specimens N2 - The utilization of additive manufacturing (AM) to fabricate robust structural components relies on understanding the nature of internal anomalies or discontinuities, which can compromise the structural integrity. While some discontinuities in AM microstructures stem from similar mechanisms as observed in more traditional processes such as casting, others are unique to the AM process. Discontinuities in AM are challenging to detect, due to their submicron size and orientation dependency. Toward the goal of improving structural integrity, minimizing discontinuities in an AM build requires an understanding of the mechanisms of formation to mitigate their occurrence. This study utilizes various techniques to evaluate the shape, size, nature and distribution of discontinuities in AM Inconel 718, in a non-hot isostatic pressed (HIPed) as-built, non-HIPed and direct age, and HIPed with two step age samples. Non-destructive synchrotron radiation refraction and transmission radiography (SXRR) provides additional information beyond that obtained with destructive optical microscopy. SXRR was able to distinguish between voids, cracks and lack of melt in, due to its sensitivity to the orientation of the discontinuity. KW - Additive manufacturing KW - X-ray refraction radiography KW - INCONEL 718 KW - Selective laser melting PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509836 DO - https://doi.org/10.1007/s11661-020-05847-5 SN - 1543-1940 VL - 51 IS - 8 SP - 4146 EP - 4157 PB - Springer AN - OPUS4-50983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bandow, N. A1 - Aitken, M. D. A1 - Geburtig, Anja A1 - Kalbe, Ute A1 - Piechotta, Christian A1 - Schoknecht, Ute A1 - Simon, Franz-Georg A1 - Stephan, Ina T1 - Using Environmental Simulations to Test the Release of Hazardous Substances from Polymer-Based Products: Are Realism and Pragmatism Mutually Exclusive Objectives? N2 - The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented. KW - Environmental simulations KW - Polymer-based products KW - Artificial weathering KW - Degradation KW - Leaching KW - Soil contact PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509310 DO - https://doi.org/10.3390/ma13122709 SN - 1996-1944 VL - 13 IS - 12 SP - Paper 2709, 22 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leidigkeit, Carolin A1 - Shokr, Mohammad A1 - Tosson, Amir A1 - Cakir, Cafer Tufan A1 - Radtke, Martin A1 - Pietsch, Ullrich A1 - Christ, Hans-Jürgen T1 - Using Energy-Dispersive Laue Diffraction to Study Dislocation Arrangements in Materials Showing Wavy and Planar Slip Behavior N2 - The present work shows an approach to monitor the evolution of the dislocation arrangement of a metallic material caused by cyclic plastic strain using white X-ray radiation in combination with an energy-dispersive detector. The method is demonstrated by single-shot experiments performed on polycrystalline nickel and α-brass, representing the pure wavy and the pure planar dislocation slip behavior. To correlate the resulting diffraction patterns with various dislocation arrangements of both metals, fatigue tests were carried out up to certain numbers of cycles and at predetermined plastic strain amplitudes. The differences in dislocation microstructure and internal stress distributions give rise to an appreciable change in the peak shape of Laue reflections, leading to unique characteristics in the respective diffraction patterns. Nickel reflections are elongated due to the high amount of cell structures leading to bending and misorientation of the lattice, whereas the present stacking faults in α-brass result in powder-like diffraction. KW - Slip behavior KW - Energy-Dispersive KW - Laue Diffraction KW - Dislocation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637964 DO - https://doi.org/10.1111/ffe.14535 SN - 1460-2695 VL - 48 IS - 3 SP - 1341 EP - 1351 PB - Wiley AN - OPUS4-63796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Wolf, Julia A1 - Mielentz, Frank A1 - Wiggenhauser, Herbert T1 - Using embedded ultrasonic sensors for active and passive concrete monitoring N2 - Challenging new constructions and ageing infrastructure are increasing the demand for permanent monitoring of loads and condition. Various methods and sensors are used for this purpose. But the technologies available today have difficulties in detecting slowly progressing locally confined damages. Extensive investigations or instrumentations are required so far for this purpose. In this study we present new sensors and data processing methods for ultrasonic transmission, which can be used for non-destructive long term monitoring of concrete. They can be mounted during construction or thereafter. Larger volumes can be monitored by a limited number of sensors for changes of material properties. The principles of ultrasonic transmission and influencing factors are presented. This latter include load, damages as well as environmental parameters as temperature or moisture. Various methods for data processing, e. g. coda wave interferometry are introduced. They allow the detection of very small changes in the medium. The embedded sensors are shown including mounting and operation. Application examples so far include small scale laboratory freeze-thaw experiments, localizing loads in larger concrete models, monitoring load effects on real structures as well as detecting acoustic events. Some sensors are operating already for several years. The sensors can be used as transmitter or receivers or switched between both roles. While most of the previous experiments have been active (at least one sensor serving as transmitter), new studies show that the sensors are useful as well for passive measurements, e. g. in acoustic emission or time reversal experiments. Besides application in civil engineering our setups can also be used for model studies in geosciences. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - SHM KW - Monitoring KW - Ultrasound concrete KW - Embedded sensors PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344652 UR - http://www.ndt.net/?id=18408 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Tokarski, T. A1 - Rychlowski, L. T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 3. Pseudosymmetry N2 - A pseudosymmetric description of the crystal lattice derived from a single wideangle Kikuchi pattern can have several causes. The small size (<15%) of the sector covered by an electron backscatter diffraction pattern, the limited precision of the projection centre position and the Kikuchi band definition are crucial. Inherent pseudosymmetries of the crystal lattice and/or structure also pose a challenge in the analysis of Kikuchi patterns. To eliminate experimental errors as much as possible, simulated Kikuchi patterns of 350 phases have been analysed using the software CALM [Nolze et al. (2021). J. Appl. Cryst. 54, 1012–1022] in order to estimate the frequency of and reasons for pseudosymmetric crystal lattice descriptions. Misinterpretations occur in particular when the atomic scattering factors of non-equivalent positions are too similar and reciprocal-lattice points are systematically missing. As an example, a pseudosymmetry prediction depending on the elements involved is discussed for binary AB compounds with B1 and B2 structure types. However, since this is impossible for more complicated phases, this approach cannot be directly applied to compounds of arbitrary composition and structure. KW - Bravais lattices KW - Pseudosymmetry KW - Lattice point density KW - Ordered/disordered structures KW - Lattice distortion PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573169 DO - https://doi.org/10.1107/s1600576723000845 SN - 0021-8898 VL - 56 IS - Pt. 2 SP - 367 EP - 380 AN - OPUS4-57316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Tokarski, T. A1 - Rychlowski, L. T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 2. Offset corrections N2 - A band width determination using the first derivative of the band profile systematically underestimates the true Bragg angle. Corrections are proposed to compensate for the resulting offset Δa/a of the mean lattice parameters derived from as many Kikuchi band widths as possible. For dynamically simulated Kikuchi patterns, Δa/a can reach up to 8% for phases with a high mean atomic number Z, whereas for much more common low-Z materials the offset decreases linearly. A predicted offset Δa/a = f(Z) is therefore proposed, which also includes the unit-cell volume and thus takes into account the packing density of the scatterers in the material. Since Z is not always available for unknown phases, its substitution by Zmax, i.e. the atomic number of the heaviest element in the compound, is still acceptable for an approximate correction. For simulated Kikuchi patterns the offset-corrected lattice parameter deviation is Δa/a < 1.5%. The lattice parameter ratios, and the angles α, β and γ between the basis vectors, are not affected at all.1.5%. The lattice parameter ratios, and the angles � , � and � between the basis vectors, are not affected at all. KW - Mean atomic number KW - Kikuchi patterns KW - Lattice parameters KW - Automated Bragg angle determination KW - Lattice parameter determination PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573153 DO - https://doi.org/10.1107/s1600576723000146 SN - 0021-8898 VL - 56 IS - Pt. 2 SP - 361 EP - 366 AN - OPUS4-57315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Tokarski, T. A1 - Rychlowski, L. T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 1. Where is the Bragg angle? N2 - The derivation of a crystal structure and its phase-specific parameters from a single wide-angle backscattered Kikuchi diffraction pattern requires reliable extraction of the Bragg angles. By means of the first derivative of the lattice profile, an attempt is made to determine fully automatically and reproducibly the band widths in simulated Kikuchi patterns. Even under such ideal conditions (projection centre, wavelength and lattice plane traces are perfectly known), this leads to a lattice parameter distribution whose mean shows a linear offset that correlates with the mean atomic number Z of the pattern-forming phase. The consideration of as many Kikuchi bands as possible reduces the errors that typically occur if only a single band is analysed. On the other hand, the width of the resulting distribution is such that higher image resolution of diffraction patterns, employing longer wavelengths to produce wider bands or the use of higher interference orders is less advantageous than commonly assumed. KW - Bragg angles KW - Kikuchi bands KW - Kikuchi patterns KW - First derivative KW - Lattice parameters PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573141 DO - https://doi.org/10.1107/S1600576723000134 SN - 0021-8898 VL - 56 IS - Pt. 2 SP - 349 EP - 360 AN - OPUS4-57314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -