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 - Sanabria, S. J.
A1 - Baensch, Franziska
A1 - Zauner, M.
A1 - Niemz, P.
T1 - In‑situ quantification of microscopic contributions of individual cells to macroscopic wood deformation with synchrotron computed tomography
N2 - Wood-based composites hold the promise of sustainable construction. Understanding the influence on wood cellular microstructure in the macroscopic mechanical behavior is key for engineering highperformance composites. In this work, we report a novel Individual Cell Tracking (ICT) approach for in-situ quantification of nanometer-scale deformations of individual wood cells during mechanical loading of macroscopic millimeter-scale wood samples. Softwood samples containing > 104 cells were subjected to controlled radial tensile and longitudinal compressive load in a synchrotron radiation micro-computed tomography (SRμCT) setup. Tracheid and wood ray cells were automatically segmented, and their geometric variations were tracked during load. Finally, interactions between microstructure deformations (lumen geometry, cell wall thickness), cellular arrangement (annual growth rings, anisotropy, wood ray presence) with the macroscopic deformation response were investigated. The results provide cellular insight into macroscopic relations, such as anisotropic Poisson effects, and allow direct observation of previously suspected wood ray reinforcing effects.
The method is also appropriate for investigation of non-linear deformation effects, such as buckling and deformation recovery after failure, and gives insight into less studied aspects, such as changes in lumen diameter and cell wall thickness during uniaxial load. ICT provides an experimental tool for direct validation of hierarchical mechanical models on real biological composites.
KW - Wood materials
KW - Micro-comuted tomography (µCT)
KW - Individual cell tracking
KW - Stress-strain behaviour
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518157
DO - https://doi.org/10.1038/S41598-020-78028-4
SN - 2045-2322
VL - 10
SP - 1
EP - 16
PB - Springer nature
AN - OPUS4-51815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sanchez Olivares, G.
A1 - Battig, Alexander
A1 - Goller, Sebastian M.
A1 - Rockel, Daniel
A1 - Ramirez Gonzáles, V.
A1 - Schartel, Bernhard
T1 - Imparting Fire Retardancy and Smoke Suppression to Leather during Tanning Processes
N2 - Leather is considered a luxury good when used in seating and upholstery. To improve safety, flame retardancy in leather is usually achieved through various finishing processes such as spray or roller coating. These treatments require processing steps that cost time and are laborintensive. One avenue to achieving flame retardancy in leather is to add flame retardants during the tanning process. However, the influence on flame retardancy exerted by specific intumescent additives specifically added during leather tanning has yet to be investigated. This work explores the roles played by intumescent additive compounds in flame retarding leather when they are added during tanning instead of applied as a coating. Via a systematic investigation of various compound mixtures, the flame retardant effects in the condensed and the gas phases are elucidated. The results show a strong impact of melamine in the gas phase and of polyphosphates in the condensed phase. Their impact was quantified in fire and smoke analysis, showing a 14% reduction in the peak of heat release rate, strongly reduced burning lengths, and a 20% reduction in total smoke release compared to nontreated leather. These results illuminate the key role played by specific compounds in the flame retardancy of leather, particularly when they are added specifically during the tanning process instead of being applied as a coating.
This method has great potential to reduce processing steps, lower costs, and improve material safety.
KW - Leather
KW - Fire protection
KW - Intumescent additives
KW - Smoke suppression
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564777
DO - https://doi.org/10.1021/acsomega.2c05633
SN - 2470-1343
VL - 7
IS - 48
SP - 44156
EP - 44169
PB - ACS
AN - OPUS4-56477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sano, Silvia Di
A1 - Costa, Giancarlo
A1 - Giordano, Pier Francesco
A1 - Pregnolato, Maria
A1 - Limongelli, Maria Pina
T1 - Multi‐risk assessment for bridges: The application of the Italian Guidelines
N2 - Bridges are essential elements in the built environment since they underpin the functioning of transportation systems. Nevertheless, they are vulnerable due to aggressive environment, demand beyond the design level, and other contingencies such as extreme events. The management of bridges represents a significant challenge for improving transport performance and ensure the safety of users. In Italy, bridge management is addressed by the recent “Guidelines for risk classification and management, safety evaluation and monitoring of existing bridges” which were issued by the Italian Ministry for Public Work in 2020. The guidelines propose an operational approach with distinctive characteristics: (i) risk‐based, i.e., based on the typical parameters of hazard, vulnerability, and exposure; (ii) multi‐level, i.e., they include six assessment levels (0‐5) of increasing complexity; and (iii) multi‐risk, i.e., they assess structural/foundation, seismic, hydrological and landslide risk. This paper presents a general overview of the 2020 Italian Guidelines and their application to a selected case study. Lessons from the application to the case study are drafted and possible criticalities highlighted.
KW - Bridge management
KW - Infrastructures
KW - Italian guidelines
KW - Structural safety
KW - Risk assessment
KW - Risk classification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653392
DO - https://doi.org/10.1002/cepa.2046
SN - 2509-7075
VL - 6
IS - 5
SP - 772
EP - 779
PB - Wiley
CY - Berlin
AN - OPUS4-65339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santi, Alberto
A1 - Schröder, Jakob
A1 - Serrano-Munoz, Itziar
A1 - Bayat, Mohamad
A1 - Hattel, Jesper Henri
T1 - Exploring the Flash Heating method in additive manufacturing for residual stress prediction: A comparative study with diffraction results from X-ray and neutron techniques
N2 - Residual stress (RS) control is crucial for ensuring the performance and reliability of components produced through laser-based powder bed fusion (PBF-LB) additive manufacturing (AM). This study evaluates the Flash Heating (FH) method as an efficient approach for RS prediction, comparing its outcomes with multiple experimental techniques, including X-ray diffraction, neutron diffraction, and layer removal methods. These experimental assessments are conducted in different regions of the component, both before and after detachment from the baseplate. The study validates the FH method and analyzes key numerical parameters, such as meta-layer height, contact time, and time-stepping strategies. Results indicate that FH effectively predicts bulk RS distributions but shows discrepancies in surface stress estimations, likely due to unaccounted factors like surface roughness. Additionally, implementing experimentally derived material properties from as-built AM samples significantly enhances model accuracy compared to conventional material datasets. These findings underscore the potential of FH for efficient RS prediction in PBF-LB while identifying areas for further improvement. Refinements should focus on incorporating anisotropic, temperature-dependent material behavior derived from as-built AM samples and surface roughness effects. This work advances the understanding of key factors necessary for accurate and computationally efficient RS prediction, supporting the optimization of AM processes.
KW - Finete element method
KW - Inconel 718
KW - Metal additive manufacturing
KW - Residual stress
KW - Thermomechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639533
DO - https://doi.org/10.1080/01495739.2025.2541862
SN - 0149-5739
SP - 1
EP - 24
PB - Taylor & Francis
AN - OPUS4-63953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santos, C.I.L.
A1 - Machado, W.S.
A1 - Wegner, Karl David
A1 - Gontijo, L.A.P.
A1 - Bettini, J.
A1 - Schiavon, M.A.
A1 - Reiss, P.
A1 - Aldakov, D.
T1 - Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells
N2 - facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 degrees C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption.
KW - Aqueous quantum dot
KW - Solar cells
KW - CUINS2 nanocrystals
KW - Colloidal semiconductor nanocrystals
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517983
DO - https://doi.org/10.3390/nano10071252
VL - 10
IS - 7
SP - 1252
PB - MDPI
AN - OPUS4-51798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santos de Freitas, M.
A1 - Araghi, R. R.
A1 - Brandenburg, E.
A1 - Leiterer, Jork
A1 - Emmerling, Franziska
A1 - Folmert, K.
A1 - Gerling-Driessen, U. I. M.
A1 - Bardiaux, B.
A1 - Böttcher, C.
A1 - Pagel, K.
A1 - Diehl, A.
A1 - v. Berlepsch, H.
A1 - Oschkinat, H.
A1 - Koksch, B.
T1 - The protofilament architecture of a de novo designed coiled coil-based amyloidogenic peptide
N2 - Amyloid fibrils are polymers formed by proteins under specific conditions and in many cases they are related to pathogenesis, such as Parkinson’s and Alzheimer’s diseases. Their hallmark is the presence of a β-sheet structure. High resolution structural data on these systems as well as information gathered from multiple complementary analytical techniques is needed, from both a fundamental and a pharmaceutical perspective. Here, a previously reported de novo designed, pH-switchable coiled coil-based peptide that undergoes structural transitions resulting in fibril formation under physiological conditions has been exhaustively characterized by transmission electron microscopy (TEM), cryo-TEM, atomic force microscopy (AFM), wide-angle X-ray scattering (WAXS) and solid-state NMR (ssNMR). Overall, a unique 2-dimensional carpet-like assembly composed of large coexisiting ribbon-like, tubular and funnel-like structures with a clearly resolved protofilament substructure is observed. Whereas electron microscopy and scattering data point somewhat more to a hairpin model of β-fibrils, ssNMR data obtained from samples with selectively labelled peptides are in agreement with both, hairpin structures and linear arrangements.
KW - Amyloid
KW - Elektronenmikroskopie
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458713
UR - https://www.sciencedirect.com/science/article/pii/S1047847718301333
DO - https://doi.org/10.1016/j.jsb.2018.05.009
SN - 1047-8477
VL - 203
IS - 3
SP - 263
EP - 272
PB - Elsevier
AN - OPUS4-45871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sarhan, R. M.
A1 - Koopman, W.
A1 - Schuetz, R.
A1 - Schmid, Thomas
A1 - Liebig, F.
A1 - Koetz, J.
A1 - Bargheer, M.
T1 - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol
N2 - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.
KW - Nanoparticles
KW - Plasmonic heating
KW - Raman spectroscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475140
DO - https://doi.org/10.1038/s41598-019-38627-2
SN - 2045-2322
VL - 9
IS - 1
SP - 3060, 1
EP - 8
PB - Nature Publishing Group
AN - OPUS4-47514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sarma, Dominik
A1 - Carl, Peter
A1 - Climent Terol, Estela
A1 - Schneider, Rudolf
A1 - Rurack, Knut
T1 - Multifunctional polystyrene core/silica shell microparticles with antifouling properties for bead-based multiplexed and quantitative analysis
N2 - Commercial bead-based assays are commonly built upon polystyrene particles. The polymeric carrier can be encoded with organic dyes and has ideal material properties for cytometric applications such as low density and high refractive index. However, functional groups are conventionally integrated during polymerization and subsequent modification is limited to the reactivity of those groups. Additionally, polystyrene as the core material leads to many hydrophobic areas still being present on the beads’ surfaces even after functionalization, Rendering the particles prone to nonspecific adsorption during an application. The latter calls for several washing steps and the use of additives in (bio)analytical assays. In this contribution, we show how these limitations can be overcome by using monodisperse polystyrene (PS) core/silica (SiO2) shell particles (SiO2@PS). Two different hydrophobic BODIPY (boron−dipyrromethene) dyes were encapsulated inside a poly(vinylpyrrolidone) (PVP) -stabilized polystyrene core in different concentrations to create 5-plex arrays in two separate detection channels of a cytometer. A subsequent modification of the silica shell with an equimolar APTES/PEGS (aminopropyltriethoxysilane/polyethylene glycol silane) blend added multifunctional properties to the hybrid core/Shell microparticles in a single step: APTES provides amino groups for the attachment of a caffeine derivative (as a hapten) to create antigen-coupled microspheres; the PEG moiety effectively suppresses nonspecific binding of antibodies, endowing the surface with antifouling properties. The particles were applied in a competitive fluorescence immunoassay in suspension, and a highly selective wash-free assay for the detection of caffeine in beverages was developed as a proof of concept.
KW - Core−shell particles
KW - Bead-based assay
KW - Multiplex
KW - Antifouling surface
KW - Mixed surface
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472931
UR - https://pubs.acs.org/doi/10.1021/acsami.8b10306
DO - https://doi.org/10.1021/acsami.8b10306
SN - 1944-8244
VL - 11
IS - 1
SP - 1321
EP - 1334
PB - American Chemical Society
CY - Online Library
AN - OPUS4-47293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sathiyamani, S.
A1 - Ngiam, S.
A1 - Bonnerot, O.
A1 - Jaengsawang, S.
A1 - Panarut, P.
A1 - Helman-Wazny, Agnieszka
A1 - Colini, C.
T1 - Material Characterisation of 19–20th Century Manuscripts from Northern Thailand
N2 - Material analysis was carried out on four manuscripts from Northern Thailand, which included two palm-leaf manuscripts and two paper manuscripts. The two palm-leaf manuscripts MS 6 and MS 7 were found to have been written in the traditional method, wherein text was incised on the surface of the leaves, and then soot applied to the surfaces, confirmed by the identification of carbon ink. MS 7 additionally showed the presence of trace levels of iron in the ink, either from soot paste or from the stylus used for inscribing. The paper manuscript MS 3 was written in iron-gall ink, with sections written using a methyl-violet based ink while MS 4 was written in carbon ink. The paper used in the case of MS 3 was found to be machine made, while khoi fibres (Streblus asper) were used for making the paper used for MS 4. A combination of traditional and modern pigments, like molybdenum orange, was used for decorating the edges and cover. The results improved our understanding of these manuscripts in particular, and also provided us with insights about the rapid adoption of modern materials and their incorporation into the production of written artefacts from Northern Thailand in the late 19th and early 20th centuries.
KW - Materials analysis
KW - Paper manuscript
KW - Palm-leaf manuscript
KW - Writing inks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652586
DO - https://doi.org/10.1515/res-2023-0028
SN - 0034-5806
VL - 45
IS - 2-3
SP - 117
EP - 140
PB - Walter de Gruyter GmbH
AN - OPUS4-65258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sauer, Hannah
A1 - Okpeke, Bright E.
A1 - Dzielendziak, Agnieszka S.
A1 - Eberwein, Robert
A1 - Baetcke, Lars
A1 - Ehlers, Sören
T1 - Comparative life cycle assessment of vacuum insulation panel core materials for liquid hydrogen storage tanks – glass bubbles compared to conventional core materials
N2 - The environmental performance of insulation materials for liquid hydrogen storage tank application is important to the development of sustainable supply chains. As new materials keep evolving, there is a need to assess their environmental impact. Therefore, this study investigates the environmental sustainability and circularity of cryogenic insulation concepts, namely vacuum insulation panels (VIPs), exclusively focussing on their core materials. Employing a cradle-to-grave life cycle assessment model, the VIP core materials are investigated with a special focus on glass bubbles. Based on the results, the global warming potential of the considered core materials, namely, glass bubbles, silica aerogel, fumed silica, expanded perlite, glass fibre, and polyurethane foam is 9.21∗10^−2, 7.00, 2.50∗10^−1, 3.63∗10^−2, 6.68∗10^−2, and 1.88 kg CO2 eq. per functional unit, respectively. In general, silica aerogel and polyurethane foam are the least environmentally friendly materials, while the most sustainable is expanded perlite, followed by glass fibre, glass bubbles, and fumed silica.
KW - LH2
KW - Insulation
KW - Cryogenic storage tank
KW - Life Cycle Assessment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655445
DO - https://doi.org/10.1016/j.ijhydene.2026.153937
SN - 0360-3199
VL - 219
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-65544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sauermoser-Yri, M.
A1 - Veldurthi, N.
A1 - Wölfle, C. H.
A1 - Svartvatn, P. J.
A1 - Flo Hoem, S. O.
A1 - Lid, M. J.
A1 - Bock, Robert
A1 - Palko, J.
A1 - Torgersen, J.
T1 - On the porosity-dependent permeability and conductivity of triply periodic minimal surface based porous media
N2 - With the fast development in the field of additive manufacturing, triply periodic minimal surface (TPMS) based porous media have recently found many uses in mechanical property tuning. However, there is still a lack of understanding in their porosity-dependent permeability and electrical as well as thermal conductivity. Here, we perform finite volume simulations on the solid and void domains of the Schoen gyroid (SG), Schwarz primitive (SP) and Schwarz primitive beam (SPB) TPMS with porosities between 63% and 88% in Ansys Fluent. A simple cubic lattice (CL) of equivalent porosity served as reference. The SPB and CL showed up to one order of magnitude higher permeabilities than the SG and SP. However, SG and SP have about 1.3 and 2.6 times the electrical and thermal conductivity of SPB and CL, respectively. Furthermore, the properties of SPB and CL are largely affected by the surface area density, whereas tortuosity variation does not impact permeability and conductivity to a major extent. Finally, empirical relations are adapted to describe the presented data and thus, they may enable future designers of TPMS based porous structures to fine-tune the geometries according to the requirements on permeability and electrical as well as thermal conductivity.
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - Biomaterials
KW - Ceramics and Composites
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585250
DO - https://doi.org/10.1016/j.jmrt.2023.09.242
SN - 2238-7854
VL - 27
SP - 585
EP - 599
PB - Elsevier B.V.
AN - OPUS4-58525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Savitsky, Viktor
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Comparative performance of DIC and optical flow algorithms for displacement and strain analysis in laser beam welding
N2 - The measurement of strain and displacement in the context of the welding process represents a significant challenge. Optical methods, such as digital image correlation (DIC) or optical flow algorithms, have demonstrated their efficacy in robust and reliable data acquisition in harsh environments, including those encountered in welding processes. Concurrently, a trade-off between the accuracy of the measurement and the computational resources required for the associated calculations must be evaluated on a case-by-case basis. The application of filters to initial images represents a technique that serves to enhance the quality and accuracy of the strain and displacement prediction. In the present study, the estimated error of two algorithms, namely the Lucas-Kanade (LK) and the inverse compositional Gauss-Newton (IC-GN), is compared on the basis of both synthetic and real welding images. The displacement field is evaluated for different zones in the laser weld seam with varying contrast performance. Based on the aforementioned results, a strain calculation was conducted for both methods, which yielded comparable results for the LK and IC-GN algorithms.
KW - Laser speckle
KW - DIC
KW - Optical flow
KW - Error estimation
KW - Strain measurement
KW - Laser beam welding
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625919
DO - https://doi.org/10.1016/j.optlaseng.2025.108870
SN - 1873-0302
VL - 187
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-62591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scacco, F.
A1 - Zerbst, Uwe
A1 - Meneghetti, G.
A1 - Madia, Mauro
T1 - Comparison between PSM and IBESS approaches for the fatigue life estimation of weldments
N2 - In the framework of the fatigue assessment of welded components, several methods are available in design standards such as the nominal stress, hot-spot stress, notch stress and linear elastic fracture mechanics approaches. The present paper aims at comparing two advanced local approaches for the fatigue strength assessment of different welded joints made of steel. The first one is IBESS which is based on short crack fracture mechanics. The second one is the PSM which instead involves the strain energy density approach. Both methods will be briefly presented, and the fatigue life prediction results discussed. The results obtained for the joint geometries considered in this work show advantages and drawbacks of the approaches, which are thoroughly analysed as well.
KW - Fatigue
KW - Welded joints
KW - FAT class
KW - IBESS
KW - Peak stress method (PSM)
KW - Finite element (FE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545139
DO - https://doi.org/10.1007/s40194-022-01284-7
SP - 1
EP - 23
PB - Springer
AN - OPUS4-54513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scales, B. S.
A1 - Hasenrück, C.
A1 - Moldaenke, L.
A1 - Hassa, J.
A1 - Rückert-Reed, C.
A1 - Rummel, C.
A1 - Völkner, C.
A1 - Rynek, R.
A1 - Busche, T.
A1 - Kalinowski, J.
A1 - Jahnke, A.
A1 - Schmitt-Jansen, M.
A1 - Wendt-Potthoff, K.
A1 - Oberbeckmann, Sonja
T1 - Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch
N2 - The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultravioletexposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce
less common carotenoids and a cluster of photosynthetic genes. This
cluster appears to originate from a potentially new species of the Rhodobacteraceae family. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as betacarotene and beta-cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria-produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water.
KW - Microplastics
KW - Biofilm
KW - Pigment
KW - Microorganisms
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605725
DO - https://doi.org/10.1111/1462-2920.16639
SN - 1462-2912
VL - 26
IS - 6
SP - e16639
PB - John Wiley & Sons Ltd.
AN - OPUS4-60572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schackmann, Oliver
A1 - Márquez Reyes, Octavio A.
A1 - Memmolo, Vittorio
A1 - Lozano, Daniel
A1 - Prager, Jens
A1 - Moll, Jochen
A1 - Kraemer, Peter
T1 - Machine learning strategies with ensemble voting for ultrasonic damage detection in composite structures under varying temperature or load conditions
N2 - In recent years, the development of machine learning (ML) techniques has led to significant progress in the field of structural health monitoring with ultrasonic-guided waves. However, a number of challenges still need to be resolved for reliable operation in realistic settings. In this work, we consider the complex problem of experimental damage detection under varying temperature or load conditions where damage locations are not included in the training set. The ML techniques proposed here include supervised and unsupervised methods originally developed for image and time series classification combined with ensemble voting. A performance demonstration of the ML techniques is presented using benchmark datasets from the open-guided waves platform. The unsupervised approach is then applied to a new dataset from an experimental campaign carried out on a composite over-wrapped pressure vessel used for hydrogen storage with real defects. Results show that ensemble voting enables the effective combination of the predictions of multiple transducer pairs, even with a limited number of strong individual classifiers. When applied to unsupervised learning, this returns high accuracy also when real damage over the structure is considered.
KW - Structural-Health-Monitoring
KW - Ultrasonic guided waves
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631571
DO - https://doi.org/10.1177/14759217251333066
SN - 1741-3168
SP - 1
EP - 19
PB - Sage Publications
AN - OPUS4-63157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schalau, Sebastian
A1 - Habib, Abdel Karim
T1 - Atmospheric wind field modelling with OpenFOAM for near-ground gas dispersion
N2 - CFD simulations of near-ground gas dispersion depend significantly on the accuracy of the wind field. When simulating wind fields with conventional RANS turbulence models, the velocity and turbulence profiles specified as inlet boundary conditions change rapidly in the approach flow region. As a result, when hazardous materials are released, the extent of hazardous areas is calculated based on an approach flow that differs significantly from the boundary conditions defined. To solve this problem, a turbulence model with consistent boundary conditions was developed to ensure a horizontally homogeneous approach flow. Instead of the logarithmic vertical velocity profile, a power law is used to overcome the problem that with the logarithmic profile, negative velocities would be calculated for heights within the roughness length. With this, the problem that the distance of the wall-adjacent cell midpoint has to be higher than the roughness length is solved, so that a high grid resolution can be ensured even in the near-ground region which is required to simulate
gas dispersion. The evaluation of the developed CFD model using the German guideline VDI 3783/9 and wind tunnel experiments with realistic obstacle configurations showed a good agreement between the calculated and the measured values and the ability to achieve a horizontally homogenous approach flow.
KW - OpenFOAM
KW - Gas dispersion
KW - Atmospheric boundary layer
KW - Turbulence model
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539095
DO - https://doi.org/10.3390/atmos12080933
VL - 12
IS - 8
SP - 933
PB - MDPI
AN - OPUS4-53909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schalau, Sebastian
A1 - Habib, Abdel Karim
A1 - Michel, S.
T1 - A modified k-ε turbulence model for heavy gas dispersion in built-up environment
N2 - For hazard assessment purposes, the dispersion of gases in complex urban areas is often a scenario to be considered. However, predicting the dispersion of heavy gases is still a challenge. In Germany, the VDI Guideline 3783, Part 1 and 2 is widely used for gas dispersion modelling. Whilst Part 1 uses a gauss model for calculating the dispersion of light or neutrally buoyant gases, Part 2 uses wind tunnel experiments to evaluate the heavier-than-air gas dispersion in generic built up areas. In practice, with this guideline, it is often not possible to adequately represent the existing obstacle configuration. To overcome this limitation, computational fluid dynamics (CFD) methods could be used. Whilst CFD models can represent obstacles in the dispersion area correctly, actual publications show that there is still further research needed to simulate the atmospheric flow and the heavy gas dispersion. This paper presents a modified k-ε-turbulence model that was developed in OpenFOAM v5.0 (England, London, The OpenFOAM Foundation Ltd Incorporated) to enhance the simulation of the atmospheric wind field and the heavy gas dispersion in built-up areas. Wind tunnel measurements for the dispersion of neutrally buoyant and heavy gases in built-up environments were used to evaluate the model. As a result, requirements for the simulation of the gas dispersion under atmospheric conditions have been identified and the model showed an overall good performance in predicting the experimental values.
KW - Atmospheric boundary layer
KW - OpenFOAM
KW - Heavy gas
KW - CFD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568898
DO - https://doi.org/10.3390/atmos14010161
VL - 14
IS - 1
SP - 1
EP - 21
PB - MDPI
AN - OPUS4-56889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schannor, Mathias
A1 - Oelze, Marcus
A1 - Traub, Heike
A1 - He, Yubei
A1 - Schmidt, Robin
A1 - Heidemann, Luisa
A1 - Savic, Lynn Jeanette
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Advancing Biomarker Research: In Situ Cu Isotope Analysis in Liver Tumors by LA-MC-ICP-MS
N2 - Stable metal isotopes have received increasing attention as medical biomarkers due to their potential to detect changes in metal metabolism related to diseases. In particular, copper stable isotopes are a powerful tool to identify isotopic variation between tumors and healthy tissue, suggesting application in cancer diagnosis. However, potential mechanisms causing isotope fractionation, such as redox- or bond-forming reactions and interactions of metals during transmembrane import and export, are less well understood. Here, we established an in situ method using laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) to advance our understanding of the underlying processes responsible for isotope fractionation between normal and diseased tissues. Gelatin-based bracketing standards and quality control reference materials, crucial for laser ablation analysis, were developed to allow correction for instrumentally induced isotope fractionation during LA-MC-ICP-MS analysis. Using such matrix-matched standards, the method achieved intermediate precisions for delta values of better than 0.15 ‰ (2 s) for inorganic reference materials and of better than 0.17 ‰ (2 s) for biological reference materials. The developed routine was tested on rabbit VX2 liver tumor samples, a model system resembling human hepatocellular carcinoma (HCC) used to study liver cancer. In situ Cu isotope compositions between healthy (𝛿65/63NIST976(Cu) = −1.5 ‰ to 0.2 ‰) and tumorous (𝛿65/63NIST976(Cu) = 0.0 ‰ to 1.3 ‰) liver tissue show distinct differences in their isotope ratios. The observed isotopic dichotomy is consistent with previous solution-based MC-ICP-MS work, showing enrichment of heavy 65Cu in cancer biopsies relative to healthy tissue.
KW - Biomarker
KW - Laser Ablation
KW - Reference Material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626865
DO - https://doi.org/10.1021/acs.analchem.4c05626
SN - 1520-6882
VL - 97
IS - 8
SP - 4425
EP - 4432
PB - American Chemical Society (ACS)
AN - OPUS4-62686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schardt, Annika
A1 - Schmitt, Johannes
A1 - Engelhard, Carsten
T1 - Single particle inductively coupled plasma mass spectrometry with nanosecond time resolution
N2 - In this proof-of-principle study, we present our contribution to single particle inductively coupled plasma mass spectrometry (spICP-MS) developments with a novel in-house built data acquisition system with nanosecond time resolution (nanoDAQ) and a matching data processing approach. The new system can continuously sample the secondary electron multiplier (SEM) detector signal and enables the detection of gold nanoparticles (AuNP) as small as 7.5 nm with the commercial single quadrupole ICP-MS instrument used in this study. Recording of the SEM signal by the nanoDAQ is performed with a dwell time of approximately 4 ns. A tailored method was developed to process this type of transient data, which is based on determining the temporal distance between detector events that is denoted as event gap (EG). We found that the inverse logarithm of EG is proportional to the particle size and that the number of detector events corresponding to a particle signal distribution can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion. Due to the high data acquisition frequency, a statistically significant number of data points can be obtained in 60 s or less and the main time limitation for analyses is merely the sample uptake time and rinsing step between analyte solutions. At this stage, the data processing method provides average information on complete data sets only and will be adapted to enable particle-by-particle analysis with future hardware/software revision.
KW - ICP-MS
KW - Nanoparticles
KW - Nanosecond time resolution
KW - Single particle detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612706
DO - https://doi.org/10.1039/d3ja00373f
SN - 1364-5544
SN - 0267-9477
VL - 39
IS - 2
SP - 389
EP - 400
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-61270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Kröger, Tommy
A1 - Keil, Karin
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - A new elemental analytical approach for microplastic sum parameter analysis—ETV/ICP-MS with CO2
N2 - Microplastics (MPs) are pervasive environmental pollutants and are considered one of the main challenges of our time. However, a fast and comprehensive analytical approach for MP analysis in complex matrices traceable to SI units is still lacking. In this context, we report a fast screening tool for the sum parameter analysis of MPs using electrothermal vaporization (ETV) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). In our proof-of-concept study, we observed size-independent detection of MPs as peaks above the 13C+ signal background in the nano- to micrometer range without limitations regarding the polymer type. Quantification of the 13C+ MP signals was accomplished via an external gas calibration utilizing dynamic dilution of carbon dioxide with argon, yielding recovery rates of 80–96% for MP reference material (RM) of polymer types commonly found in the environment. The applicability to a soil sample was demonstrated through spiking experiments with a polyethylene (PE) MP RM in soil. The limit of detection (LOD) was estimated to be 0.13 µg C, equaling the detection of a single spherical low-density-PE particle of about 70 µm, and a limit of quantification (LOQ) of 0.42 µg C.
KW - ETV/ICP-MS
KW - Mikroplastik
KW - Summenparameter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646418
DO - https://doi.org/10.1007/s00216-025-06146-x
SN - 1618-2642
SP - 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-64641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Pfeifer, Jens
A1 - Vogl, Jochen
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - Tin fractionation analysis in sediment samples via on-line ID ETV/ICP-MS
N2 - We report a quantification approach for directly determining total tin and tin-based pollutants/species in sediments via electrothermal vaporization/inductively coupled plasma-mass spectrometry (ETV/ICP-MS) utilizing an on-line isotope dilution mass spectrometry (IDMS) approach. The method was developed and validated using an estuarine sediment reference material (BCR-277R), yielding a recovery of 106%. A relative standard deviation (RSD) of 14%, comparable to published data using a similar method, was obtained. A limit of quantification (LOQ) was estimated at 0.008 mg Sn kg−1 and sufficient for quantifying the total tin mass fraction of surface sediments along the tidal River Elbe course. Hereby, a decrease towards the river mouth, presumably due to dilution effects by less polluted marine sediment, was observed. Besides total tin, monitoring of organotin compounds (OTCs)/species is of interest in sediments due to their toxic effects on aquatic life. The method’s capability was extended by separating an OTC fraction in a sediment certified reference material (CRM) through the ETV temperature program. While spiking experiments with OTC standards confirmed the assignment, only a small fraction of the total certified OTC amount (3%), likely due to matrix effects, was recovered. However, applying the method to real-world samples, OTCs were detectable along the River Elbe course. By this, we demonstrated the potential of our method as a complementary fast-screening approach to species-specific analysis procedures.
KW - ETV
KW - Sn-Speciation
KW - Sediment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640137
DO - https://doi.org/10.1007/s00216-025-06064-y
SN - 1618-2642
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-64013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Effect of heat control on mechanical properties and residual stresses at the transition zone of component and substrate in hybrid DED‑arc manufacturing
N2 - In hybrid additive manufacturing, components or semi-finished products manufactured by conventional primary forming are enhanced or modified by additive manufactured structures. However, systematic investigations focusing on the critical transition area between the specific properties of the substrate (like high-strength) and the additively manufactured component, made of specific filler material, are still lacking. The focus of the present study was to determine the influence of heat control on the Δt8/5 cooling time, the distortion, the mechanical properties, and the residual stresses in the transition area of hybrid-additive components. This contributed to the knowledge regarding the safe avoidance of cold cracking, excessive distortion, a reduction in yield stress, and the implementation of hybrid DED-arc manufacturing. The heat control was varied by means of heat input and working temperature such that the Δt8/5 cooling times corresponded to the recommended processing range. The heat input has a greater influence on the cooling time in the transition area than the working temperature. Working temperature and the total energy applied per layer have a significant effect on component distortion. The lowest working temperature of 100 °C in combination with the highest total energy per layer leads to significantly greater distortion compared to manufacturing with a high working temperature of 300 °C and low total energy per layer. In addition, the longitudinal residual compressive stresses in the sensitive transition area are reduced from − 500 MPa to approx. − 200 MPa by adjusting the working temperature from 100 to 300 °C. Such complex interactions must be clarified comprehensively to provide users with easily applicable processing recommendations and standard specifications for an economical hybrid additive manufacturing of components made, for example, of high-strength steels in the transition area.
T2 - IIW Annual Assembly and International Conference
CY - Rhodes Island, Greece
DA - 07.07.2024
KW - Hybrid additive manufacturing
KW - DED-arc
KW - Heat control
KW - High-strength metals
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630415
DO - https://doi.org/10.1007/s40194-025-02036-z
SN - 1878-6669
SP - 1
EP - 15
PB - Springer
AN - OPUS4-63041
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Heat control and design‑related effects on the properties and welding stresses in WAAM components of high‑strength structural steels
N2 - Commercial high-strength fller metals for wire arc additive manufacturing (WAAM) are already available. However, widespread industrial use is currently limited due to a lack of quantitative knowledge and guidelines regarding welding stresses and component safety during manufacture and operation for WAAM structures. In a joint research project, the process- and material-related as well as design infuences associated with residual stress formation and the risk of cold cracking are being investigated. For this purpose, reference specimens are welded fully automated with defned dimensions and systematic variation of heat control using a special, high-strength WAAM fller metal (yield strength>790 MPa). Heat control is varied by means of heat input (200–650 kJ/m) and interlayer temperature (100–300 °C). The ∆t8/5 cooling times correspond with the recommendations of fller metal producers (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. High heat input leads to a lower tensile stress in the component and may cause unfavorable microstructure and mechanical properties. However, a sufciently low interlayer temperature is likely to be suitable for obtaining adequate properties at a reduced tensile stress level when welding with high heat input. The component design afects heat dissipation conditions and the intensity of restraint during welding and has a signifcant infuence on the residual stress. These complex interactions are analyzed within this investigation. The aim is to provide easily applicable processing recommendations and standard specifcations for an economical, appropriate, and crack-safe WAAM of high-strength steels.
KW - GMA welding
KW - Additive manufacturing
KW - Residual stresses
KW - High-strength steel
KW - Cold cracking safety
KW - Heat control
KW - Wind energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567397
DO - https://doi.org/10.1007/s40194-022-01450-x
SN - 1878-6669
VL - 2022
SP - 1
EP - 11
PB - Springer
CY - Berlin
AN - OPUS4-56739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Influence of Heat Control on Properties and Residual Stresses of Additive-Welded High-Strength Steel Components
N2 - This contributed to the knowledge regarding the safe avoidance of cold cracking. In addition to a thermophysical simulation using a dilatometer of different high-strength steels with subsequent tensile testing, reference WAAM specimens (open hollow cuboids) were welded while utilizing a high-strength filler metal (ultimate tensile strength > 790 MPa). The heat control was varied by means of the heat input and interlayer temperature such that the Dt8/5 cooling times corresponded to the recommended processing range (approx. 5 s to 20 s). For the heat input, significant effects were exhibited, in particular on the local residual stresses in the component. Welding with an excessive heat input or deposition rate may lead to low cooling rates, and hence to unfavorable microstructure and component properties, but at the same time, is intended to result in lower tensile residual stress levels. Such complex interactions must ultimately be clarified to provide users with easily applicable processing recommendations and standard specifications for an economical WAAM of high-strength steels. These investigations demonstrated a major influence of the heat input on both the cooling conditions and the residual stresses of components manufactured withWAAM using high-strength filler materials. A higher heat input led to longer cooling times (Dt8/5) and approx. 200 MPa lower residual stresses in the surface of the top layer.
KW - WAAM
KW - Additive manufacturing
KW - Heat control
KW - High-strength filler metals
KW - Residual stress
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553982
UR - https://www.mdpi.com/2075-4701/12/6/951
DO - https://doi.org/10.3390/met12060951
VL - 12
IS - 6
SP - 951
PB - MDPI
AN - OPUS4-55398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharpmann, Philippa
A1 - Leonhardt, Robert
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
A1 - Krug von Nidda, Jonas
T1 - Exploring restrictive overdischarge cycling as a method to accelerate characteristic ageing in lithium-ion cells
N2 - This study presents a test protocol that greatly accelerates the ageing process of lithium-ion battery cells comprising a positive electrode of nickel manganese cobalt oxide while preserving their characteristic degradation upon cyclic ageing. Applying a repetitive restricted overdischarge, resulting in a depth of discharge larger than 100%, a capacity loss of 20% is achieved over five times faster compared to conventional cycling. The well-known overdischarge degradation phenomenon of copper current collector dissolution is deliberately prevented by setting a discharge cutoff voltage above the theoretical threshold of copper oxidation. Hence, the accelerated degradation can be primarily connected to solid electrolyte interphase growth.
A comparative assessment of the ageing dynamics using electrochemical impedance spectroscopy and differential voltage analysis hints towards similar, characteristic degradation processes during accelerated and conventional ageing. A post-ageing examination of the electrical behaviour (i.e., coulombic and energy efficiency, capacity fade) under reference conditions reveals very little to no lasting damages caused by
overdischarging. Additionally, post-mortem analysis discloses no increased copper dissolution when comparing cells subjected to accelerated and conventional ageing. Generally, the developed ageing method appears suitable for providing cells with a defined state of health at a reasonable timescale without altering the main degradation mechanisms significantly.
KW - Lithium-ion cell
KW - Accelerated ageing
KW - Overdischarge
KW - Degradation processes
KW - Differential voltage analysis
KW - Electrochemical impedance spectroscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650917
DO - https://doi.org/10.1016/j.jpowsour.2025.239072
SN - 0378-7753
VL - 665
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schartel, Bernhard
T1 - Phosphorus-based flame retardancy mechanisms - Old hat or a starting point for future development?
N2 - Different kinds of additive and reactive flame retardants containing phosphorus are increasingly successful as halogen-free alternatives for various polymeric materials and applications. Phosphorus can act in the condensed phase by enhancing charring, yielding intumescence, or through inorganic glass formation; and in the gas phase through flame inhibition. Occurrence and efficiency depend, not only on the flame retardant itself, but also on its interaction with pyrolysing polymeric material and additives. Flame retardancy is sensitive to modification of the flame retardant, the use of synergists/adjuvants, and changes to the polymeric material. A detailed understanding facilitates the launch of tailored and targeted development.
KW - Fire retardancy
KW - Red phosphorus
KW - Phosphate
KW - Phosphonate
KW - Phosphinate
KW - Phosphine oxide
KW - Flame inhibition
KW - Charring
KW - Intumescence
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-220368
DO - https://doi.org/10.3390/ma3104710
SN - 1996-1944
VL - 3
IS - 10
SP - 4710
EP - 4745
PB - MDPI
CY - Basel
AN - OPUS4-22036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures
N2 - The development within the offshore wind sector towards more powerful turbines combined with increasing water depth for new wind parks is challenging both the designer as well as the manufacturer of bottom fixed support structures. Besides XL-monopiles, the market developed an innovative and economic jacket support structure which is based on automatically manufactured tubular joints combined with standardized pipes. Besides the improvements for a serial manufacturing process the automatically welded tubular joints show a great potential in terms of fatigue resistance e.g. due to a smooth weld geometry without sharp notches. However, these benefits are not considered yet within the fatigue design process of automatically manufactured jacket substructures according to current standards due to the lack of suitable S-N curves. Therefore, 32 axial fatigue tests on single and double-sided automatically welded tubular X-joints have been performed to determine a new hot spot stress related S-N curve. Based on these constant amplitude fatigue tests a new S-N curve equal to a FAT 126 curve was computed which implicitly includes the benefits of the automatically welding procedure.
T2 - EERA Deep Wind 2020
CY - Trondheim, Norway
DA - 15.01.2020
KW - Notch stress approach
KW - Fatigue tests
KW - Automated manufacturing
KW - Tubular X-joints
KW - Structural stress approach
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518509
DO - https://doi.org/10.1088/1742-6596/1669/1/012022
VL - 1669
SP - 012022
PB - IOP Publishing Ltd
AN - OPUS4-51850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Automatically Welded Tubular X-Joints for Jacket Substructures
N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented.
KW - Tubular X-joints
KW - Fatigue tests
KW - Technical crack detection
KW - Local fatigue spproaches
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513228
DO - https://doi.org/10.1002/cepa.1140
VL - 3
IS - 3-4
SP - 823
EP - 828
PB - Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG
CY - Berlin
AN - OPUS4-51322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Ernst, W.
A1 - Spindler, H.
A1 - Kannengießer, Thomas
T1 - Hydrogen-assisted cracking of GMA welded 960 MPa grade high-strength steels
N2 - High-strength steels with yield strength of 960 MPa are susceptible to hydrogen-assisted cracking (HAC) during welding processing. In the present paper, the implant test is used to study HAC in a quenched and tempered steel S960QL and a high-strength steel produced by thermo-mechanical controlled process S960MC. Welding is performed using the gas metal arc welding process. Furthermore, diffusible hydrogen concentration (HD) in arc weld metal is determined. Based on the implant test results, lower critical stress (LCS) for complete fracture, critical implant stress for crack initiation, and embrittlement index (EI) are determined. At HD of 1.66 ml/100 g, LCS is 605 MPa and 817 MPa for S960QL and S960MC, respectively. EI is 0.30 and 0.46 for S960QL and S960MC, respectively. Fracture surfaces of S960QL show higher degradation with reduced deformation. Both, higher EI of S960MC and fractography show better resistance to HAC in the HAZ of S960MC compared to S960QL.
KW - High-strength steel
KW - Welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - Heat-affected zone
KW - Implant test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510307
DO - https://doi.org/10.1016/j.ijhydene.2020.05.077
SN - 0360-3199
VL - 45
IS - 38
SP - 20080
EP - 20093
PB - Elsevier Ltd
CY - Amsterdam, NL
AN - OPUS4-51030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Rhode, Michael
A1 - Yahyaoui, Hamza
A1 - Kannengießer, Thomas
ED - Lippold, J.
ED - Böllinghaus, Thomas
ED - Norrish, J.
ED - Scotti, A.
T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process
N2 - High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series withMod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.
KW - High-strength steel
KW - GMA welding
KW - Diffusible hydrogen
KW - Implant test
KW - Fractography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515330
DO - https://doi.org/10.1007/s40194-020-00978-0
SN - 1878-6669
SN - 0043-2288
VL - 64
IS - 12
SP - 1997
EP - 2009
PB - Springer
CY - Berlin Heidelberg
AN - OPUS4-51533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Schröder, Nina
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Hydrogen-Assisted Cracking in GMA Welding of High-Strength Structural Steel—A New Look into This Issue at Narrow Groove
N2 - Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated.
As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding.
KW - High-strength structural steel
KW - Gas metal arc welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - TEKKEN
KW - Residual stresses
KW - Weld metal cracking
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527260
DO - https://doi.org/10.3390/met11060904
VL - 11
IS - 6
SP - 904
PB - MDPI
CY - Basel
AN - OPUS4-52726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheffler, Franziska
A1 - Fleck, Mirjam
A1 - Busch, Richard
A1 - Casado, Santiago
A1 - Gnecco, Enrico
A1 - Tielemann, Christopher
A1 - Brauer, Delia S.
A1 - Müller, Ralf
T1 - Surface Crystallization of Barium Fresnoite Glass: Annealing Atmosphere, Crystal Morphology and Orientation
N2 - Controlled oriented crystallization of glass surfaces is desired for high precision applications, since the uppermost crystal layer significantly influences the properties of the material. In contrast to previous studies, the data presented here deal with separated crystals growing at defect-free surfaces in four atmospheres with different degrees of humidity (ambient/dry air, argon and vacuum). A glass with the composition 2 BaO–TiO2–2.75 SiO2 was heat-treated at 825 °C until fresnoite (Ba2TiSi2O8) grew to a significant size. The crystal growth rate is found to increase with increasing humidity. The morphology of the crystals changes from highly distorted dendrites in the driest atmosphere (vacuum) to circular/spear-head-shaped crystals in the wettest atmosphere (ambient air), which we attribute to a decrease in viscosity of the glass surface due to water uptake. The least distorted crystals appear in the form of depressions of up to 6 µm. This has an influence on the observed crystal orientation, as measured by electron backscatter diffraction (EBSD). The pulled-in crystals change the orientation during growth relative to the flat glass surface due to an enrichment in SiO2 at the crystal fronts. This confirms that the orientation of crystals is not fixed following nucleation.
KW - Fresnoite
KW - Surface crystallization
KW - Crystal growth
KW - Crystal morphology
KW - Crystal orientation
KW - EBSD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587230
DO - https://doi.org/10.3390/cryst13030475
VL - 13
IS - 3
SP - 1
EP - 17
PB - MDPI AG
CY - Basel
AN - OPUS4-58723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schepers, Winfried
A1 - Brinkgreve, RBJ
A1 - Appel, S.
T1 - Recommendations on finite element modelling of non-seismic excitation in soil-structure interaction problems
N2 - Nowadays geotechnical engineering firms have powerful software tools to extent their consult-ing business also into dynamic soil-structure interaction, which before has been restricted to a rather small community of specialized experts in this field, and they certainly do. This is par-ticularly true with respect to non-seismic sources, that is all kinds of human induced vibrations. Hence, there is a demand from clients as well as from contractors to have guidance on the re-quirements as well as the limits of numerical modelling of soil-structure interaction. From the literature as well as from relevant standards, recommendations for the numerical modelling of soil-structure interaction problems involving seismic actions are well known, e. g. ASCE/SEI 4-16. There are, however, some particularities when dealing with human-induced vibrations, which are absent in seismic analyses. For human-induced excitations very little specific guid-ance has been published in the past. A machine foundation on a homogeneous half space ex-cited by harmonic loads with excitation frequency between 4 Hz and 64 Hz has been ana-lysed by means of several commercially available software packages. Parametric studies have been performed to verify if recommendations for seismic soil-structure analyses are valid for non-seismic analyses as well. This paper provides details on the benchmark example and the most important conclusions from the undertaken parametric studies.
T2 - XII International Conference on Structural Dynamics
CY - Delft, Netherlands
DA - 02.07.2023
KW - Numerische Analysen
KW - Referenzbeispiel
KW - Maschinenfundament
KW - Wellenausbreitung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604931
DO - https://doi.org/10.1088/1742-6596/2647/8/082014
SN - 1742-6596
VL - 2647
IS - 25
SP - 1
EP - 13
PB - IOP Publishing
AN - OPUS4-60493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schepers, Winfried
A1 - Kulke, D.
T1 - Cone penetration tests and dynamic soil properties
N2 - ISO 14837-32:2015 and DIN EN 1998-1/NA:2021 as well as prEN 1997-2:2022 allow for us-ing correlations between the results of in-situ soil penetration tests and shear wave velocity (or shear modulus) to determine soil properties to be used in dynamic analyses. While the ISO and prEN standards even provide some recommendations on specific correlations to be used, the DIN standard does not. Due to the statistical nature of such correlations their general applica-bility has to be verified. We collected data sets from test sites from Germany as well as New Zealand at which cone penetration tests (CPT) as well as seismic site investigation methods were conducted. These sites comprise sandy soils as well as clayey soils, mixed soils as well as glacial soils. We compare the results of several correlations between CPT results and shear wave velocity. The accuracy of such correlations is assessed with respect to the accuracy of seismic in-situ tests. It turns out that for clean sands such correlations between CPT and Vs have a similar order of variability as seismic in-situ tests conducted at the same site. The higher the fines portion of the soil, the higher the variability of the statistical correlations, and conse-quently the less the general applicability. For glacial soils and other special soil types usage of statistical correlations to determine dynamic soil properties is not recommended.
T2 - XII International Conference on Structural Dynamics
CY - Delft, Netherlands
DA - 02.07.2023
KW - Wave propagation
KW - Soil properties
KW - Dynamic excitation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604887
DO - https://doi.org/10.1088/1742-6596/2647/25/252005
VL - 2647
SP - 1
EP - 11
PB - IOP Publishing
CY - Bristol
AN - OPUS4-60488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherb, T.
A1 - Fantin, Andrea
A1 - Checcia, S.
A1 - Stephan-Scherb, Christiane
A1 - Escolástico, S.
A1 - Franz, A.
A1 - Seeger, J.
A1 - Meulenberg, W. A.
A1 - d'Acapito, F.
A1 - Serra, J. M.
T1 - Unravelling the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d mixed ionic electronic conductors
N2 - Mixed ionic electronic conducting ceramics Nd6-yWO12-d (d is the Oxygen deficiency) provide excellent stability in harsh environments containing strongly reactive gases such as CO2, CO, H2, H2O or H2S. Due to this chemical stability, they are promising and cost-efficient candidate materials for gas separation, catalytic membrane reactors and protonic ceramic fuel cell technologies. As in La6-yWO12-d, the ionic/electronic transport mechanism in Nd6-yWO12-d is expected to be largely controlled by the crystal structure, the conclusive determination of which is still lacking. This work presents a crystallographic study of Nd5.8WO12-d and molybdenum-substituted Nd5.7W0.75Mo0.25O12-d prepared by the citrate complexation route. High-resolution synchrotron and neutron powder diffraction data were used in combined Rietveld refinements to unravel the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d. Both investigated samples crystallize in a defect fluorite crystal structure with space group Fm3m and doubled unit-cell parameter due to cation ordering. Mo replacesWat bothWyckoff sites 4a and 48h and is evenly distributed, in contrast with La6-yWO12-d. X-ray absorption spectroscopy as a function of partial pressure pO2 in the near-edge regions excludes oxidation state changes of Nd (Nd3+) and W(W6+) in reducing conditions: the enhanced hydrogen permeation, i.e. ambipolar conduction, observed in Mo-substituted Nd6-yWO12-d is therefore explained by the higher Mo reducibility and the creation of additional – disordered – oxygen vacancies.
KW - Powder diffraction
KW - Mixed conductors
KW - X-ray absorption spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514607
DO - https://doi.org/10.1107/S1600576720012698
VL - 53
SP - 1471
EP - 1483
AN - OPUS4-51460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherb, Tobias
A1 - Kimber, S. A. J.
A1 - Stephan, Christiane
A1 - Henry, P. F.
A1 - Schumacher, G.
A1 - Escolástico, S.
A1 - Serra, J. M.
A1 - Seeger, J.
A1 - Just, J.
A1 - Hill, A.H.
A1 - Banhart, J.
T1 - Nanoscale order in the frustrated mixed conductor La5.6WO12-Delta
N2 - This article reports a comprehensive investigation of the average and local structure of La5.6WO12-δ, which has excellent mixed proton, electron and oxide ion conduction suitable for device applications. Synchrotron X-ray and neutron powder diffraction show that a cubic fluorite supercell describes the average structure, with highly disordered lanthanum and oxide positions. On average, the tungsten sites are sixfold coordinated and a trace [3.7 (1.3)%] of anti-site disorder is detected. In addition to sharp Bragg reflections, strong diffuse neutron scattering is observed, which hints at short-range order. Plausible local configurations are considered and it is shown that the defect chemistry implies a simple 'chemical exchange' interaction that favours ordered WO6 octahedra. The local model is confirmed by synchrotron X-ray pair distribution function analysis and EXAFS experiments performed at the La K and W L-3 edges. It is shown that ordered domains of similar to 3.5 nm are found, implying that mixed conduction in La5.6WO12-δ is associated with a defective glassy-like anion sublattice. The origins of this ground state are proposed to lie in the nonbipartite nature of the face-centred cubic lattice and the pairwise interactions which link the orientation of neighbouring octahedral WO6 sites. This 'function through frustration' could provide a means of designing new mixed conductors.
KW - neutron diffraction
KW - x-ray diffraction
KW - proton conductors
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366756
DO - https://doi.org/10.1107/S1600576716006415
SN - 1600-5767
VL - 49
IS - Issue 3
SP - 997
EP - 1008
PB - International Union of Crystallography
CY - Chester, UK
AN - OPUS4-36675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherr, J. F.
A1 - Kollofrath, J.
A1 - Popovics, J. S.
A1 - Bühling, Benjamin
A1 - Grosse, C. U.
T1 - Detection of Delaminations in Concrete Plates Using a Laser Ablation Impact Echo Technique
N2 - This study investigates the non-destructive detection of delaminations in concrete plates using non-contact laser ablation, instead of the conventional hammer excitation, as part of the impact echo method. We performed tests on five concrete specimens of different sizes, two of which contained artificial delaminations. A range of steel ball hammers was used as reference impulse sources, the responses of which were compared with wave excitation generated by a 7 ns pulsed 1064 nm Nd:YAG laser with 150 mJ pulse energy. Signals were recorded by surface-mounted accelerometers and two contactless methods: microphones and a laser Doppler vibrometer. The laser generates frequencies across a broad range of frequencies (0 to 150 kHz) but with much less energy than the hammers' narrower frequency spectra; the laser pulse energy transferred into the specimen is 0.07 mJ, corresponding to about 0.5 ‰ of the impulse source energy. Because of this, the thick intact plates' characteristic thickness stretch resonance frequency can be reliably detected by the hammer excitations but not when using laser excitation. However, the laser can excite low-frequency flexural vibration modes over a shallow delamination at 3 cm depth. The low-frequency flexural vibration results are verified by numerical natural frequency analysis.
KW - Concrete testing
KW - Defect detection
KW - Lamb waves
KW - Impact echo
KW - Non-destructive testing
KW - Vibration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567932
DO - https://doi.org/10.1007/s10921-022-00921-x
SN - 0195-9298
VL - 42
IS - 1
SP - 1
EP - 14
PB - Springer
AN - OPUS4-56793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuerlein, C.
A1 - Andrieux, J.
A1 - Michels, M.
A1 - Lackner, F.
A1 - Chiriac, R.
A1 - Hagner, M.
A1 - Di Michiel, M.
A1 - Meyer, Christian
A1 - Toche, F.
ED - Foley, C. P.
T1 - Effect of the fabrication route on the phase and volume changes during the reaction heat treatment of Nb3Sn superconducting wires
N2 - Accelerator magnets that can reach magnetic fields well beyond the Nb-Ti performance limits are presently being built and developed, using Nb3Sn superconductors. This technology requires reaction heat treatment (RHT) of the magnet coils, during which Nb3Sn is formed from its ductile precursor materials (a “wind and react” approach). The Nb3Sn microstructure and microchemistry are strongly influenced by the conductor fabrication route, and by the Phase changes during RHT. By combining in situ differential scanning calorimetry, high Energy synchrotron x-ray diffraction, and micro-tomography experiments, we have acquired a unique data set that describes in great detail the phase and microstructure changes that take place during the processing of restacked rod process (RRP), powder-in-tube (PIT), and internal tin (IT) Nb3Sn wires. At temperatures below 450 ° the phase evolutions in the three wire types are similar, with respectively solid state interdiffusion of Cu and Sn, Cu6Sn5 formation, and Cu6Sn5 peritectic transformation. Distinct differences in phase evolutions in the wires are found when temperatures exceed 450 °C. The volume changes of the conductor during RHT are a difficulty in the production of Nb3Sn accelerator magnets. We compare the wire diameter changes measured in situ by dilatometry with the phase and void volume evolution of the three types of Nb3Sn wire. Unlike the Nb3Sn wire length changes, the wire diameter evolution is characteristic for each Nb3Sn wire type. The strongest volume increase, of about 5%, is observed in the RRP wire, where the main diameter increase occurs above 600 °C upon Nb3Sn formation.
KW - Nb3Sn
KW - Microstructure
KW - Phase transformations
KW - Volume changes
KW - X-ray diffraction
KW - Differential scanning calorimetry
KW - Synchrotron micro-tomography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505128
DO - https://doi.org/10.1088/1361-6668/ab627c
VL - 33
IS - 3
SP - 034004
PB - IOP Publishing
CY - Bristol (UK)
AN - OPUS4-50512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheurrell, Kerstin
A1 - B. Martins, Inês C.
A1 - Murray, Claire
A1 - Emmerling, Franziska
T1 - Exploring the role of solvent polarity in mechanochemical Knoevenagel condensation: in situ investigation and isolation of reaction intermediates
N2 - Mechanochemistry has proven to be a highly effective method for the synthesis of organic compounds. We studied the kinetics of the catalyst-free Knoevenagel reaction between 4-nitrobenzaldehyde and malononitrile, activated and driven by ball milling. The reaction was investigated in the absence of solvents (neat grinding) and in the presence of solvents with different polarities (liquid-assisted grinding). The reaction was monitored using time-resolved in situ Raman spectroscopy and powder X-ray diffraction (PXRD). Our results indicate a direct relationship between solvent polarity and reaction kinetics, with higher solvent polarity leading to faster product (2-(4-nitrobenzylidone)malononitrile) formation. For the first time, we were able to isolate and determine the structure of an intermediate 2-(hydroxy(4-nitrophenyl)methyl)malononitrile based on PXRD data.
KW - Physical and Theoretical Chemistry
KW - General Physics and Astronomy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588071
DO - https://doi.org/10.1039/D3CP02883F
SN - 1463-9076
VL - 25
IS - 35
SP - 23637
EP - 23644
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuschner, Nils
A1 - Oster, Simon
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Comparison of NIR and SWIR thermography for defect detection in Laser Powder Bed Fusion
N2 - Since laser powder bed fusion (PBF-LB/M) is prone to the formation of defects during the building process, a fundamental requirement for widespread application is to find ways to assure safety and reliability of the additively manufactured parts. A possible solution for this problem lies in the usage of in-situ thermographic monitoring for defect detection. In this contribution we investigate possibilities and limitations of the VIS/NIR wavelength range for defect detection. A VIS/NIR camera can be based on conventional silicon-based sensors which typically have much higher spatial and temporal resolution in the same price range but are more limited in the detectable temperature range than infrared sensors designed for longer wavelengths. To investigate the influence, we compared the thermographic signatures during the creation of artificially provoked defects by local parameter variations in test specimens made of a nickel alloy (UNS N07208) for two different wavelength ranges (~980 nm and ~1600 nm).
KW - Laser powder bed fusion
KW - PBF-LB/M
KW - Thermography
KW - Additive manufacturing
KW - NDT
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610380
DO - https://doi.org/10.1016/j.procir.2024.08.122
VL - 124
SP - 301
EP - 304
PB - Elsevier B.V.
AN - OPUS4-61038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schiaroli, Alice
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Eberwein, Robert
A1 - Ustolin, Federico
A1 - Cozzani, Valerio
T1 - Modelling the behaviour of cryogenic liquid hydrogen tanks engulfed in fire
N2 - The safe use of liquid hydrogen as a clean fuel requires a deep understanding of its behaviour in accident scenarios. Among other scenarios, the possible involvement of cryogenic liquid hydrogen tanks in engulfing fires is of particular concern, due to the potentially severe consequences. This study proposes a computational fluid dynamic model suitable to simulate the behaviour of liquid hydrogen tanks equipped with multi-layer insulation (MLI) engulfed in fire. An original approach has been developed to assess the progressive degradation of the performance of the thermal insulation, that is crucial in determining the tank pressurization and failure. The model is validated against full-scale experimental fire tests. The outcomes of the model reproduce the progressive pressurization and the opening time of the pressure relief valve within 2 % error. The results demonstrate the importance of accounting for the dynamic evolution of the progressive degradation of the insulation when evaluating tank pressurization, and they highlight the limitations of empirical, simplified state-of-the-art approaches. Furthermore, the analysis evidences the key role of the fire temperature in governing tank response, stressing the need for proper fire characterization to support reliable modelling of fire scenarios and the development of emergency planning and mitigation strategies ensuring the structural integrity of liquid hydrogen tanks during fire attacks.
KW - LH2
KW - LNG
KW - Fire
KW - Tank
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652920
DO - https://doi.org/10.1016/j.psep.2025.108319
SN - 0957-5820
VL - 206
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-65292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schiaroli, Alice
A1 - Mata, Christian
A1 - Scarponi, Giordano Emrys
A1 - Habib, Abdel Karim
A1 - Kluge, Martin
A1 - Ustolin, Federico
A1 - Cozzani, Valerio
T1 - Digital image processing for the advanced characterization and simulation of experimental fire tests
N2 - The fire engulfment of storage tanks of hazardous materials is among the most critical scenarios in hazard assessment of industrial value chains. Laboratory and full-scale experimental trials are used to test the tank performance and integrity in such scenarios. However, strong uncertainties usually affect the actual fire load experienced by the tank, in particular when large-scale experiments are carried out in open test fields. Such uncertainties arise from several factors difficult to control during experimental tests, such as the atmospheric conditions as there is the influence of wind drifts influencing the actual fire engulfment, the flame temperature and the flame dynamic distribution around the target. Consequently, verifying the concordance of an experimental test with standard test criteria and defining accurate boundary conditions in correlated model simulations is challenging. In this study, the development of a novel method for the analysis of fire conditions based on image processing is presented. The approach allows identifying the flame coverage on the target surface during the test and provides an accurate map of the flame distribution on the equipment over time. The approach is tested using experimental data from a full-scale fire test campaign carried out on liquid hydrogen cryogenic tanks. The results prove to be accurate in replicating the experimental temperatures measured on the outer tank shell during the test. The proposed methodology can be used to better understand the results of experimental fire tests and to characterize realistic fire scenarios, also supporting the definition of fire test requirements. Moreover, the approach produces results that can be implemented as advanced space-time-varying boundary conditions in simulation models, improving their accuracy in reproducing real cases.
KW - Fire test
KW - Digital image processing
KW - Flame coverage
KW - Storage tank
KW - Boundary conditions
KW - Fire engulfment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636956
DO - https://doi.org/10.1016/j.psep.2025.107571
SN - 0957-5820
VL - 201
IS - B
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-63695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schick, D.
A1 - Herzog, M.
A1 - Bojahr, A.
A1 - Leitenberger, W.
A1 - Hertwig, Andreas
A1 - Shayduk, R.
A1 - Bargheer, M.
T1 - Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction
N2 - Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates.
KW - Festkörperphysik
KW - Dünnschichttechnik
KW - Ellipsometrie
KW - Röntgenbeugung
KW - Optische Konstanten
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322471
DO - https://doi.org/10.1063/1.4901228
SN - 2329-7778
VL - 1
IS - 6
SP - 064501-1 - 064501-13
PB - AIP Publishing LLC
CY - Melville, NY
AN - OPUS4-32247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Portella, Pedro Dolabella
A1 - Skrotzki, Birgit
T1 - FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing
N2 - The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability.
KW - Data Interoperability
KW - Domain Ontology Development
KW - FAIR Data Management
KW - Knowledge Representation
KW - Tensile Test Ontology
KW - Semantic Web Technologies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598142
DO - https://doi.org/10.1002/adem.202400138
SN - 1438-1656
SP - 1
EP - 19
PB - Wiley VHC-Verlag
AN - OPUS4-59814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bruns, Sebastian
A1 - Bayerlein, Bernd
A1 - Kryeziu, Jehona
A1 - Schaarschmidt, Jörg
A1 - Waitelonis, Jörg
A1 - Dolabella Portella, Pedro
A1 - Durst, Karsten
T1 - Seamless Science: Lifting Experimental Mechanical Testing Lab Data to an Interoperable Semantic Representation
N2 - The scientific landscape is undergoing rapid transformations with the advent of the digital age which revolutionizes research methodologies. In materials science and engineering, an adoption of modern data management techniques is desirable to maximize the efficiency and accessibility of research efforts. Traditional practices in testing laboratories are usually inadequate for efficient data acquisition and utilization as they lead to local storage and difficulty in publication and correlation with other results. Electronic laboratory notebooks (ELNs) are promising prospects in this respect. Semantic concepts and ontologies enhance interoperability by standardizing experimental data representation. An in‐laboratory pipeline seamlessly integrating an ELN with transformation scripts to convert experimental into interoperable data in a machine‐actionable format is created in this study as a proof of concept. Tensile test results and the corresponding tensile test ontology are used exemplary. Linking ELN data to semantic concepts enriches the stored information while improving interpretability and reusability. Involving undergraduate students builds a bridge between theory and practice during their training and promotes their digital skills. This study underscores the potential of ELNs and knowledge representations as beneficial means toward improved data management practices that enhance collaborative research and education while ensuring compatibility with evolving standards and technologies.
KW - Semantic Data
KW - Data Integration
KW - Tensile Test Ontology
KW - Electronic Lab Notebook
KW - Wissensrepräsentation
KW - Education
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618251
DO - https://doi.org/10.1002/adem.202401527
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-61825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Böhning, Martin
T1 - Modernizing FNCT data handling in polymer labs: Towards efficient management
N2 - A streamlined Python-based workflow for transforming Full-Notch Creep Test (FNCT) data into organized, machine-actionable formats is presented. The workflow automates the conversion of raw FNCT data from classic CSV and Excel files into structured outputs that facilitate future semantic integration. Emphasizing practical data handling, the approach includes automation scripts for efficient data extraction, transformation, and storage, which culminate in well-ordered files. This transformation paves the way for potential semantic data integration and facilitates access for users with varying levels of digital experience to enhanced data management in polymer research and testing.
KW - PE-HD
KW - Full-Notch Creep Test (FNCT)
KW - Environmental Stress Cracking (ESC)
KW - Data Interoperability
KW - FAIR Data
KW - Semantic Data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637826
DO - https://doi.org/10.1016/j.commatsci.2025.114085
SN - 0927-0256
VL - 259
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-63782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Characteristics of environmental stress cracking of PE-HD induced by biodiesel and diesel fuels
N2 - In the context of the increasing effect of carbon dioxide emissions on the global climate biodiesel produced from renewable sources has emerged as a promising contender replacing fossil fuels, especially in long-range transport vehicles, using existing engines and infrastructure.
High-density polyethylene is one of the prevailing materials for pipe and container applications for storage and transport of such fuels, both, from fossil and renewable resources. The contact with the respective fuels raises questions concerning material compatibility as biodiesel exhibits significant differences compared to conventional diesel fuel affecting its sorption and plasticization behavior in polyethylene. In this study, its behavior with respect to environmental stress cracking, considered one of the most frequent damage mechanisms leading to failure of polymer parts and packaging, was evaluated using the well-established Full Notch Creep Test. This
approach allows for a detailed fracture surface analysis using imaging techniques, such as optical and laser scanning microscopy, as well as infrared spectroscopy. Comparing the environmental stress cracking behavior in standard surfactant solutions with that in biodiesel and diesel, respective crack propagation rates, showing different levels of acceleration, were determined and details of the underlying mechanisms could be revealed.
Furthermore, the specific infrared absorption of the biodiesel’s ester functionality allows its semi-quantitative determination on the fracture surface of the tested specimens after failure. Thus, a preferred uptake of sorptive fluids in the fracture zone due to local morphological changes of the polyethylene could be directly evidenced by infrared spectroscopy.
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Confocal laser scanning microscopy (LSM)
KW - Biodiesel
KW - Diesel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608591
DO - https://doi.org/10.1016/j.polymertesting.2024.108547
SN - 0142-9418
VL - 138
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-60859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Unveiling Effects of Biodiesel and Diesel on Environmental Stress Cracking of PE-HD
N2 - The behavior of high‐density polyethylene with respect to resistance against environmental stress cracking (ESC) is usually regarded as an inherent material property being specific for respective types of PE‐HD and tested using standardized methods, conditions, and also standard testing liquids (usually aqueous surfactant solutions). On the other hand, for practical applications the ESC behavior of those polymeric materials, commonly used for pipes or containers, in contact with other liquids (e.g., fuels) is often of relevant interest, but for a reasonable assessment, where consistent benchmark data for a direct comparison are often missing, it is essential to determine the actually prevailing failure mode and classify it related to crack propagation or other mechanisms. Using the well‐established Full Notch Creep Test, which favorably allows for a detailed microscopic fracture surface analysis after failure, the behavior of two typical PE‐HD types for container applications is investigated in biodiesel and diesel and compared to a standard surfactant solution. This enables a clear identification of characteristic features of the interaction of biodiesel and diesel as sorptive fuels in contact with the polymer, revealing the complex interplay of sorption and plasticization as well as ESC inducing effects on PE‐HD, which could be clearly shown for both fuels.
KW - Biodiesel
KW - Confocal laser scanning microscopy (LSM)
KW - Diesel
KW - Full notch creep test (FNCT)
KW - Plasticization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650525
DO - https://doi.org/10.1002/pen.70239
SN - 0032-3888
SP - 1
EP - 16
PB - Wiley
CY - Hoboken (NJ)
AN - OPUS4-65052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Niebergall, Ute
A1 - Marschall, Niklas
A1 - Alig, I.
A1 - Böhning, Martin
T1 - A phenomenological criterion for an optical assessment of PE-HD fracture surfaces obtained from FNCT
N2 - The full-notch creep test (FNCT) is a common test method to evaluate the environmental stress cracking (ESC) behavior of high-density polyethylene (PE-HD), e.g. for container materials. The test procedure as specified in ISO 16770 provides a comparative measure of the resistance against ESC using the time to failure of PE-HD specimens under constant mechanical load in a well-defined liquid test environment. Since the craze-crack damage mechanism underlying the ESC phenomenon is associated with brittle failure, the occurrence of a predominantly brittle fracture surface is a prerequisite to consider an FNCT measurement as representative for ESC, i.e. a time to failure dominated by craze-crack propagation.
The craze-crack propagation continuously reduces the effective residual cross-sectional area of the specimen during the test, which results in a corresponding increase of the effective mechanical stress. Thus, a transition to ductile shear deformation is inevitable at later stages of the test, leading usually to a pronounced central ligament.
Therefore, an optical evaluation of FNCT fracture surfaces concerning their brittleness is essential. An enhanced imaging analysis of FNCT fracture surfaces enables a detailed assessment of craze-crack Propagation during ESC. In this study, laser scanning microscopy (LSM) was employed to evaluate whether FNCT fracture surfaces are representative with respect to craze-crack propagation and ESC. Based on LSM height data, a phenomenological criterion is proposed to assess the validity of distinct FNCT measurements. This criterion is
supposed to facilitate a quick evaluation of FNCT results in practical routine testing. Its applicability is verified on a sample basis for seven different commercial PE-HD container materials.
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Laser scanning microscopy (LSM)
KW - Fracture surfaces
KW - Optical criterion of brittleness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521012
DO - https://doi.org/10.1016/j.polymertesting.2020.107002
VL - 94
SP - 107002
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-52101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Niebergall, Ute
A1 - Marschall, Niklas
A1 - Meinel, Dietmar
A1 - Böhning, Martin
T1 - Relation of craze to crack length during slow crack growth phenomena in high‐density polyethylene
N2 - The craze‐crack mechanism occurring in high‐density polyethylene (HDPE) causing slow crack growth and environmental stress cracking is investigated in detail with respect to the relation of crack length and the related craze zone. This is essential for the understanding of the resulting features of the formed fracture surface and their interpretation in the context of the transition from crack propagation to ductile shear deformation. It turns out that an already formed craze zone does not inevitably result in formation of a propagating crack, but could also undergo ductile failure. For the examination, the full notch creep test (FNCT) was employed with a subsequent advanced fracture surface analysis that was performed using various imaging techniques: light microscopy, laser scanning microscopy, scanning electron microscopy, and X‐ray micro computed tomography scan. FNCT specimens were progressively damaged for increasing durations under standard test conditions applying Arkopal, the standard surfactant solution, and biodiesel as test media were used to analyze the stepwise growth of cracks and crazes. From considerations based on well‐established fracture mechanics approaches, a theoretical correlation between the length of the actual crack and the length of the preceding craze zone was established that could be evidenced and affirmed by FNCT fracture surface analysis. Moreover, the yield strength of a HDPE material exposed to a certain medium as detected by a classic tensile test was found to be the crucial value of true stress to induce the transition from crack propagation due to the craze‐crack mechanism to shear deformation during FNCT measurements.
Highlights
- Progress of crack formation in high‐density polyethylene is analyzed by different imaging techniques
- Determined growth rates depend on distinction between craze zone and crack
- The ratio of the present crack to the anteceding craze zone is validated theoretically
- The transition from crack propagation to ductile shear deformation is identified
- An already formed craze zone may still fail by ductile mechanisms
KW - Craze-crack mechanism
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Laser scanning microscopy (LSM)
KW - Slow crack growth (SCG)
KW - X-ray computed tomography (CT)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601831
DO - https://doi.org/10.1002/pen.26698
SN - 1548-2634
VL - 64
IS - 6
SP - 2387
EP - 2403
PB - Wiley
AN - OPUS4-60183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized Laser Dispersing of Titanium-Based Particles for Improving the Tribological Performance of Hot Stamping Tools
N2 - Within the scope of this work, a new surface engineering technology named laser implantation has been investigated, in order to improve the tribological performance of hot stamping tools. This technique is based on manufacturing highly wear-resistant, separated, and elevated microfeatures by embedding hard ceramic particles into the tool surface via pulsed laser radiation.
Hence, the topography and material properties of the tool are modified, which influences the thermal and tribological interactions at the blank-die interface. To verify these assumptions and to clarify the cause–effect relations, different titanium-based particles (TiB2, TiC, TiN) were laser-implanted and subsequently analyzed regarding to their geometrical shape and mechanical properties. Afterwards, quenching tests as well as tribological experiments were carried out by using titanium-diboride as the most promising implantation material for reducing the tribological load due to high hardness value of the generated implants. Compared to conventional tooling systems, the modified tool surfaces revealed a significantly higher wear resistance as well as reduced friction forces while offering the possibility to adjust the thermal interactions at the blank-die interface. Based on these results, a tailored tool surface modification can be pursued in future research work, in order to enhance the effectiveness of the hot stamping technology.
KW - Hot stamping
KW - Tribology
KW - Surface modification
KW - Localized laser dispersing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510981
DO - https://doi.org/10.3390/jmmp4030068
VL - 4
IS - 3
SP - 68
PB - MDPI
AN - OPUS4-51098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized dispersing of TiB2 and TiN particles via pulsed laser radiation for improving the tribological performance of hot stamping tools
N2 - The aim of this study is to increase the tribological performance of hot stamping tools by using a laser implantation process. This technique allows the fabrication of separated, elevated and dome-shaped microfeatures on the tool surface in consequence of a localized dispersing of ceramic particles via pulsed laser radiation. Hence, the topography and material properties of the tool are modified, which influences the tribological interactions at the blank-die interface. However, an appropriate selection of ceramic particles is an essential prerequisite, in order to obtain tailored and highly wear resistant surface features. In this regard, different titanium-based hard particles (TiB2 and TiN) were laser-implanted on hot working tool specimens and subsequently tested by means of a modified pin-on-disk test regarding to their wear and friction behavior.
KW - Surface modification
KW - Tribology
KW - Laser implantation
KW - Hot working tool steel
KW - Hot stamping
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514171
DO - https://doi.org/10.1016/j.procir.2020.09.069
VL - 94
SP - 901
EP - 904
PB - Elsevier B.V.
AN - OPUS4-51417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlegel, Moritz-Caspar
A1 - Koch, Claudia
A1 - Mirtsch, Mona
A1 - Harrer, Andrea
T1 - Smart Products Enable Smart Regulations—Optimal Durability Requirements Facilitated by the IoT
N2 - The challenges and opportunities linked with IoT have been intensively discussed in recent years. The connectivity of things over their entire life cycle and the smart properties associated with it provide new functionalities and unprecedented availability of (usage) data. This offers huge opportunities for manufacturers, service providers, users, and also policymakers. The latter May impact policy areas such as the regulations on resource and materials efficiency under the Ecodesign Directive 2009/125/EC. With the general approach as it is practiced today, legal requirements are usually set for entire product groups without considering the products individually, including user behavior and environmental conditions. The increasing number of smart products and the growing availability of product data are sparking a discussion on whether these requirements could be more product and application-specific. This paper presents a method for calculating the economically and ecologically optimal durability of a product. It allows determining the point in time when a product should be replaced by combining consumer data with product design data. This novel Approach could contribute to making product regulation more flexible and possibly more efficient. In this context, fundamental challenges associated with smart products in policymaking are also discussed.
KW - Ecodesign
KW - Internet of Things
KW - Connectivity
KW - Resource efficiency
KW - Policy making
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524924
DO - https://doi.org/10.3390/su13084395
VL - 13
IS - 8
SP - 4395
PB - MDPI
CY - Basel
AN - OPUS4-52492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlichting, S.
A1 - Hönig, Gerald
A1 - Müßener, J.
A1 - Hille, P.
A1 - Grieb, T.
A1 - Westerkamp, S.
A1 - Teubert, J.
A1 - Schörmann, J.
A1 - Wagner, M.R.
A1 - Rosenauer, A.
A1 - Eickhoff, M.
A1 - Hoffmann, A.
A1 - Callsen, G.
T1 - Suppression of the quantum-confined Stark effect in polar nitride heterostructures
N2 - Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.
KW - Nanophotonics
KW - Photonic devices
KW - Single photon and quantum effects
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457884
DO - https://doi.org/10.1038/s42005-018-0044-1
SN - 2399-3650
VL - 1
SP - 1
EP - 8
PB - Springer Nature
CY - London
AN - OPUS4-45788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bethke, John
A1 - Goedecke, Thomas
T1 - How To Measure The Angle of Repose of Hazardous Substances in the Test Centers for Dangerous Goods Packagings
N2 - The flow properties of powdery or granular filling substances for dangerous goods packagings are safety-relevant parameters. To specify the flow behavior, the angle of repose is measured in the recognized test centers for dangerous goods packagings in Germany. Previous investigations performed on non-hazardous substances revealed that some of the methods currently used have disadvantages in application. Additionally, for occupational health and safety reasons, it was generally viewed critically to carry out measurements of the angle of repose for dangerous goods at all. Instead, the dimensionless Hausner ratio to describe the flow behavior was proposed.
In this work, the investigations were extended to real hazardous substances to concretize the assessment. Five exemplary hazardous substances were tested for their angle of repose using the methods commonly applied in the test centers. The Hausner ratio was also determined. In addition, the influence of a different climatic preconditioning on the angle of repose measurement was examined using three selected non-hazardous bulk materials.
The results show that the measurement of the angle of repose is not fundamentally excluded for dangerous goods. However, for reasons of applicability, repeatability and occupational health and safety, only the ISO method can be applied for dangerous filling substances. This method provides conservative results regarding a safety-related evaluation of flow properties for the transport of dangerous goods.
In principle, both the ISO method and the determination of the Hausner ratio can be used for dangerous goods. It is also essential especially with finely powdered filling goods, to carry out controlled preconditioning.
KW - Angle of repose
KW - Flow properties
KW - Flowability
KW - Hausner ratio
KW - Powders
KW - Sift-proofness
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576552
DO - https://doi.org/10.1002/pts.2756
SN - 0894-3214
SP - 1
EP - 20
PB - Wiley
AN - OPUS4-57655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bethke, John
A1 - Vogler, Nico
A1 - Goedecke, Thomas
T1 - Flow properties of powdery or granular filling substances of dangerous goods packagings - Comparison of the measurement of the angle of repose and the determination of the Hausner ratio
N2 - To ensure safety when transporting dangerous goods, it is important to specify the flow properties of the respective solid filling substance of the packagings. For this purpose, the angle of repose is currently used for the UN approvals in Germany. Measurements were carried out on 12 powdery or granular substances applying the angle of repose measuring methods customary in the test centres. The results of the methods differ significantly from each other. In addition, some of the techniques cannot be applied for very cohesive or coarse-grained materials. The results for the angle of repose show a strong scatter for some constellations (coefficient of variation more than 20 %). Safety during transport of dangerous goods cannot be guaranteed with this currently practiced system of measuring the angle of repose. As a consequence, an alternative parameter to characterize the flow properties of bulk materials should be used in the recognized test centers for dangerous goods packagings, such as the Hausner ratio. This approach leads to more precise test results for the substances examined (maximum coefficient of variation 2.8 %). It also has advantages in terms of applicability and occupational safety.
Since the flow properties are safety-relevant, both in terms of mechanical safety and safety against the release of dangerous substances, the testing practice in the recognized test labs should be improved and standardized.
KW - Sift-proofness
KW - Powders
KW - Flowability
KW - Flow properties
KW - Angle of repose
KW - Hausner ratio
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552990
DO - https://doi.org/10.1002/pts.2678
SP - 1
EP - 18
PB - Wiley online library
AN - OPUS4-55299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bruchno, Martin
A1 - Thomas, Goedecke
T1 - Release of Powdery or Granular Substances from Intact Dangerous Goods Bags During Road Transport - Analysis of the Causes and Development of a Test Concept
N2 - The leaks of dangerous goods from actually intact bags detected in the years 2018 to 2020 tend to be at an almost constant high level. These releases of powdery or granular dangerous goods represent violations of the sift-proofness required in the dangerous goods regulations. This article first analyzes the causes.
The components of the bags that are affected by leaks are micro-perforations, joins and closures, in particular internal sleeve valves. A distinction must be made between bags closed in conformity with or contrary to the manufacturer's instructions. The particle release is determined by a number of influencing factors of the filling substance, the packaging and other boundary conditions.
Therefore, a comprehensive test concept is developed in this work, which takes all these factors into account. The application of this test concept facilitates the planning of the test setup and the experiments. On this basis, the complex mechanisms involved in the release of solid substances can be systematically investigated in the test laboratory.
To prevent releases of powdery or granular substances from intact bags, it is necessary that the user has access to the closing instructions and the relevant properties of the test substance used for the design type approval. Further experimental investigations are needed to assess whether filling substances change their properties during transport and whether this enables them to escape.
KW - Bags
KW - Dangerous goods packagings
KW - Leak
KW - Particles
KW - Sift-proofness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527287
DO - https://doi.org/10.1002/pts.2575
SN - 0894-3214
VL - 34
IS - 7
SP - 435
EP - 446
PB - Wiley
AN - OPUS4-52728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Neitsch, Marcel
A1 - Goedecke, Thomas
T1 - Industrial leak testing of dangerous goods packagings
N2 - The Dangerous Goods Regulations currently do not include limit leakage rates orsensitivity requirements for industrial leak testing procedures that are equivalent tothe bubble test, which is the prescribed test method for design type testing ofdangerous goods packagings. During series production of such packagings, variousmethods are used, which often do not meet the requirements of the bubble test withregard to important criteria.Sensitivity, flow direction, pressure level and automatability are particularly importantfactors when selecting a suitable industrial leak testing method.The following methods are in principle both suitable and equally effective as thebubble test: pressure rise test (vacuum chamber), ultrasonic bubble leak detectionand gas detection methods (pressure technique by accumulation and vacuumchamber technique).To ensure a uniform test level during design type testing and production line leaktesting and therefore a comparable safety level as required by the Dangerous GoodsRegulations, it is necessary to include a more precise specification in these regula-tions. This requires, on the one hand, information about the sensitivity of the bubbletest and, on the other hand, the inclusion of a list of suitable, equally effective indus-trial test methods with their specific boundary conditions.
T2 - 22nd IAPRI World Packaging
CY - Online meeting
KW - Bubble test
KW - Dangerous goods packagings
KW - Industrial leak testing
KW - Leakproofness test
KW - Series production
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507521
DO - https://doi.org/10.1002/pts.2502
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-50752
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Seidler, Oliver
A1 - Goedecke, Thomas
A1 - Kraume, M.
T1 - Helium leak testing of dangerous goods packagings
N2 - The International Dangerous Goods Regulations prescribe the immersion under water method (“bubble test”) as standard method for the leakproofness test of dangerous goods packagings. But this test procedure acts as a test method for leak localisation, not for quantitative leakage rates measurement. Additionally, the sensitivity in detecting leaks of small diameters is restricted, depending on the test liquid and the test pressure. The bubble test is not suitable for a comparison with quantitative limit leakage rates based on realistic transport conditions. This is especially important when estimating the risk of the formation of an explosive atmosphere during the intercontinental carriage of dangerous goods packagings in freight containers. To compare measured leakage rates with limit leakage rates, a quantitative leak testing procedure is required. Therefore a new approach for dangerous goods packagings is implemented: The pressure technique by accumulation using Helium as a tracer gas. This work presents the test equipment necessary for the quantitative measurement of Helium leakage rates through closures of different kinds of dangerous goods packagings. The essential steps to achieve good repeatable results are: A controlled Helium filling process to reach a defined test pressure in the test sample, a sufficient homogenisation of the Helium-air-mixture inside the test sample and the ensuring of a constant pressure level of the test sample during the test. The Helium loss rate of the accumulation chamber has to be measured separately to receive a correction factor for the measured leakage rates. Different constructional measures are introduced to prevent a disturbing influence of the Helium leakage rate of the filling valves on the measurement results. Methods to estimate the disturbing effect of Helium permeation through permeable parts of the test sample are also presented. As a supporting method for the experimental investigations the Helium sniffer test can be applied. This practical application-oriented advice can enable other users to establish a pressure technique by accumulation for their own technical field.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Überdruckverfahren
KW - Gefahrgutverpackungen
KW - Dichtheit
KW - Helium
KW - Dangerous goods packagings
KW - Leakproofness
KW - Helium
KW - Pressure technique
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371376
UR - http://ndt.net/?id=19785
SN - 1435-4934
VL - 21
IS - 7
SP - 1
EP - 10
PB - NDT.net
CY - Kirchwald
AN - OPUS4-37137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Goldammer, Ole
A1 - Bader, Julia
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Introducing AFS ([Al(SO3F)3]x) – a thermally stable, readily available, and catalytically active solid Lewis superacid
N2 - This paper introduces the thermally stable, solid Lewis superacid aluminium tris(fluorosulfate) (AFS), that is easy-to-synthesize from commercially available starting materials. Its applicability, e.g. in catalytic C–F bond activations, is shown.
KW - Lewis Acid
KW - C-F activation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601001
DO - https://doi.org/10.1039/D4SC01753F
SN - 2041-6520
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Krappe, Alexander R.
A1 - Fürstenwerth, Paul C.
A1 - Brosius, Amelie L.
A1 - Fasting, Carlo
A1 - Hoffmann, Kurt F.
A1 - Resch-Genger, Ute
A1 - Eigler, Siegfried
A1 - Steinhauer, Simon
A1 - Riedel, Sebastian
T1 - Luminescent Perhalofluoro Trityl Radicals
N2 - In this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red−NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals.
KW - Dye
KW - Fluorescence
KW - Radical
KW - Synthesis
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Polarity
KW - Polymer
KW - Solvatchromism
KW - Excimer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647973
DO - https://doi.org/10.1021/jacs.5c16418
SN - 0002-7863
VL - 147
IS - 46
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmalz, Alina
A1 - Eby, Charles Gaston
A1 - Moss, Caitlin
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Thermally Robust 1D Cu(I) Phosphonate Coordination Polymer Exhibiting Enhanced Proton Conductivity via Humidity‐Driven Pathways
N2 - The development of thermally stable solid-state proton conductors (SSPCs) is crucial for advancing energy-conversion devices such as proton-exchange membrane fuel cells (PEMFCs). In this work, we report the solvothermal synthesis and characterization of a novel, 1D Cu(I) coordination polymer, {Cu(ADP)0.5(BPY)}n (BAM-5), based on anthracenediylphosphonate (H2ADP) and 4,40 -bipyridine (BPY). Single-crystal X-ray diffraction revealed that BAM-5 crystallizes in the triclinic space group P1 and shows a 1D ladder structure connected by the H2ADP and organic BPY linkers, which is assembled into a 2D layer via O−H···O hydrogen bonding interactions between uncoordinated oxygen and the O−H of the phosphonate group. Thermogravimetric and dynamic water sorption analysis demonstrated exceptional thermal robustness of BAM-5 until 230°C and notable water affinity. Proton conductivity measurements found increasing proton conductive properties with increasing temperature and relative humidity.The latter is correlated with the material’s water uptake since the structure itself does not contain any permanent lattice water molecules. A maximum proton conductivity of 6.6 × 10−6 S cm−1 was found at 80°C and 98% RH. To the best of our knowledge, no dense, nonporous 1D coordination polymer without lattice or coordinated solvent molecules has shown comparable proton con� ductivity. The high activation energy suggests a combination of both, a Grotthuss-type proton hopping through the hydrogen� bonded framework, and a vehicular process, in which protons are carried along with absorbed water molecules.
KW - Coordination polymers
KW - Phosphonate ligand
KW - Proton conduction
KW - X-ray diffraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651382
DO - https://doi.org/10.1002/zaac.202500187
SN - 0044-2313
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-65138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Dariz, P.
T1 - Editorial for the special issue "Modern Raman spectroscopy of minerals"
N2 - Raman spectroscopy provides vibrational fingerprints of chemical compounds enabling their unambiguous identification. The assignment of Raman spectra to minerals is straightforward, if appropriate reference data is accessible. Modern couplings of Raman spectroscopy with microscopy (Raman microspectroscopy) merge the high structural specificity with down to sub-micrometre spatial resolution. This analytical tool has high potential not only in the identification of minerals from natural sources but also for studying the complex microstructure and mineral distribution of both ancient and modern man-made materials. In addition to the chemical identity of minerals, Raman spectra are affected by crystal orientations (varying relative Raman band intensities); (sub)stoichiometric compositional changes (e.g., in solid solution series), traces of foreign ions, strain (the latter three shifting Raman bands); and crystallinity (changing Raman band widths), enabling a comprehensive physico-chemical characterisation of minerals. Thus, Raman spectroscopy – including its in situ measurement capabilities – provides possibilities to study mineral paragenesis in both, natural and man-made samples at the micrometre scale. While in 1928 the first experimental evidence for inelastic light scattering was provided by C. V. Raman and K. S. Krishnan by using sunlight for excitation, filters for selecting the inelastically scattered light, and their eyes for detection (later, photographic plates for acquisition of spectra were employed), modern Raman spectrometers make use of laser excitation, dispersive spectrographs and charge coupled device (CCD) detection. This Special Issue includes technological developments and applications in the field of modern Raman spectroscopy of minerals in a broad sense, from natural mineral deposits and archaeological objects to inorganic phases in man-made materials. The studied minerals include fossil resins, typical rock-forming minerals (calcite, quartz, forsterite), iron-sulphur species (e.g., mackinawite), a range of sulphates (gypsum, bassanite, anhydrite III, anhydrite II, celestine, barite, ternesite), as well as silicate minerals like garnets (e.g., almandine).
KW - Raman spectroscopy
KW - Raman microspectroscopy
KW - Mineral identification
KW - Physico-chemical characterisation of minerals
KW - Mineral paragenesis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515041
DO - https://doi.org/10.3390/min10100860
VL - 10
SP - 860
PB - MDPI
CY - Basel
AN - OPUS4-51504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Dariz, P.
T1 - Raman Microspectroscopic Imaging of Binder Remnants in Historical Mortars Reveals Processing Conditions
N2 - Binder remnants in historical mortars represent a record of the connection between the raw materials that enter the kiln, the process parameters, and the end product of the calcination. Raman microspectroscopy combines high structural sensitivity with micrometre to sub-micrometre spatial resolution and compatibility with conventional thin-sectional samples in an almost unique fashion, making it an interesting complementary extension of the existing methodological arsenal for mortar analysis. Raman spectra are vibrational fingerprints of crystalline and amorphous compounds, and contain marker bands that are specific for minerals and their polymorphic forms. Relative intensities of bands that are related to the same crystalline species change according to crystal orientations, and band shifts can be caused by the incorporation of foreign ions into crystal lattices, as well as stoichiometric changes within solid solution series. Finally, variations in crystallinity affect band widths. These effects are demonstrated based on the analysis of three historical mortar samples: micrometric distribution maps of phases and polymorphs, crystal orientations, and compositional variations of solid solution series of unreacted clinker grains in the Portland cement mortars of two 19th century castings, and the crystallinities of thermal anhydrite clusters in a high-fired medieval gypsum mortar as a measure for the applied burning temperature were successfully acquired.
KW - Cement clinker remnants
KW - High-fired gypsum
KW - Thermal anhydrite
KW - Spectroscopic imaging
KW - Raman microscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515038
DO - https://doi.org/10.3390/heritage2020102
VL - 2
IS - 2
SP - 1662
EP - 1683
PB - MDPI
CY - Basel
AN - OPUS4-51503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Hidde, Julia
A1 - Grünier, Sophie
A1 - Jungnickel, Robert
A1 - Dariz, P.
A1 - Riedel, Jens
A1 - Neuhaus, B.
T1 - Ageing effects in mountig media of microscope slide samples from natural history collections: A case study with Canada balsam and Permount™
N2 - Microscope slide collections represent extremely valuable depositories of research material in a natural history, forensic, veterinary, and medical context. Unfortunately, most mounting media of these slides deteriorate over time, with the reason for this not yet understood at all. In this study, Raman spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, and different types of light microscopy were used to investigate the ageing behaviour of naturally aged slides from museum collections and the experimentally aged media of Canada balsam and Permount™, representing a natural and a synthetic resin, respectively, with both being based on mixtures of various terpenes. Whereas Canada balsam clearly revealed chemical ageing processes, visible as increasing colouration, Permount™ showed physical deterioration recognisable by the increasing number of cracks, which even often impacted a mounted specimen. Noticeable changes to the chemical and physical properties of these mounting media take decades in the case of Canada balsam but just a few years in the case of Permount™. Our results question whether or not Canada balsam should really be regarded as a mounting medium that lasts for centuries, if its increasing degree of polymerisation can lead to a mount which is no longer restorable.
KW - Deterioration
KW - Microscope slides
KW - Mounting media
KW - Raman spectroscopy
KW - UV–Vis spectroscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537632
DO - https://doi.org/10.3390/polym13132112
VL - 13
IS - 13
SP - 1
EP - 27
PB - MDPI
CY - Basel
AN - OPUS4-53763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Jungnickel, Robert
A1 - Dariz, P.
T1 - Insights into the CaSO4–H2O System: A Raman-Spectroscopic Study
N2 - Even though being the subject of natural scientific research for many decades, the system CaSO4–H2O, consisting of the five crystalline phases gypsum, bassanite, and the anhydrites III, II, and I, has left many open questions for research. Raman spectroscopy was used because of its structural sensitivity and in situ measurement capability to obtain further insight by studying phase transitions in both ex situ and in situ experiments. The findings include significant contributions to the completeness and understanding of Raman spectroscopic data of the system. The dehydration path gypsum–bassanite–anhydrite III was shown to have strong parallels to a physical drying process, which depends on many parameters beyond the burning temperature. Raman band width determination was demonstrated to enable the quantitative discrimination of α-bassanite and β-bassanite as well as the postulated three sub-forms of anhydrite II (AII), which are all based on differences in crystallinity. In the latter case, the observed continuous structural variations over increasing burning temperatures were elucidated as a combination of decreasing surface areas and healing of crystal lattice defects. We propose an only two-fold sub-division of AII into reactive “disordered AII” and much less reactive “crystalline AII” with a transition temperature of 650°C ± 50 K.
KW - Gypsum
KW - Bassanite
KW - Hemihydrate
KW - Anhydrite
KW - Raman spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506701
DO - https://doi.org/10.3390/min10020115
SN - 2075-163X
VL - 10
IS - 2
SP - 115, 35
PB - MDPI
CY - Basel
AN - OPUS4-50670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Kraft, Ronja
A1 - Dariz, P.
T1 - Shedding light onto the spectra of lime - Part 2: Raman spectra of Ca and Mg carbonates and the role of d-block element luminescence
N2 - We previously described the observation of a characteristic narrowband red luminescence emission of burnt lime (CaO), whose reason was unknown so far. This study presents Raman spectra of Mg5 CO3)4(OH)2∙4H2O, Mg5(CO3)4(OH)2, MgCO3, CaMgCO3 and CaCO3 (in limestone powder) as well as luminescence spectra of their calcination products. Comparison of the latter revealed MgO:Cr3+ as the source of the red lime luminescence in all studied samples, containing magnesium oxide as major component, minor component or trace. Spectral characteristics and theoretical background of the luminescence emission of d-block elements integrated in crystal lattices are discussed with the aim of sharpening the awareness for this effect in the Raman community and promoting its application in materials analysis. The latter is demonstrated by the Raman microspectroscopic imaging of the distributions of both Raman-active and Raman-inactive phases in clinker remnants in a 19th-century meso Portland cement mortar sample, which contain relatively high amounts of free lime detected in the form of both luminescing CaO and Raman-scattering Ca(OH)2, owing to exposure of the surface of the thin section to humid air. A combination of light and Raman spectroscopy revealed a calcium–magnesium–iron sulphide phase, indicating sulphurous raw materials and/or solid fuels employed in the calcination process, which in contrast to previously described morphologies of sulphides in cement clinker form extensive greenish black layers on free lime crystals.
KW - Calcium carbonates
KW - Raman spectroscopy
KW - Luminescence
KW - Magnesium carbonates
KW - Meso Portland cement
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537611
DO - https://doi.org/10.1002/jrs.6174
SN - 0377-0486
VL - 52
IS - 8
SP - 1462
EP - 1472
PB - Wiley Analytical Science
AN - OPUS4-53761
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 - JOUR
A1 - Schmidt, Birgit Angelika
A1 - Ziemann, M. A
A1 - Pentzien, Simone
A1 - Gabsch, T.
A1 - Koch, W.
A1 - Krüger, Jörg
T1 - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road
N2 - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified.
KW - Wall paintings
KW - Central Asia
KW - Silk Road
KW - Pigments
KW - Microscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357297
DO - https://doi.org/10.1179/2047058414Y.0000000152
VL - 61
IS - 2
SP - 113
EP - 122
PB - Routledge Taylor & Francis Group
CY - London
AN - OPUS4-35729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, C.
A1 - Hensen, C.
A1 - Wallmann, K.
A1 - Liebetrau, V.
A1 - Tatzel, Michael
A1 - Schurr, S. L.
A1 - Kutterolf, S.
A1 - Haffert, L.
A1 - Geilert, Sonja
A1 - Hübscher, C.
A1 - Lebas, E.
A1 - Heuser, A.
A1 - Schmidt, M.
A1 - Strauss, H.
A1 - Vogl, Jochen
A1 - Hansteen, T.
T1 - Origin of High Mg and SO4 Fluids in Sediments of the Terceira Rift, Azores‐Indications for Caminite Dissolution in a Waning Hydrothermal System
N2 - During R/V Meteor cruise 141/1, pore fluids of near surface sediments were investigated to find indications for hydrothermal activity in the Terceira Rift (TR), a hyperslow spreading center in the Central North Atlantic Ocean. To date, submarine hydrothermal fluid venting in the TR has only been reported for the D. João de Castro seamount, which presently seems to be inactive. Pore fluids sampled close to a volcanic cone at 2,800‐m water depth show an anomalous composition with Mg, SO4, and total alkalinity concentrations significantly higher than seawater and a nearby reference core. The most straightforward way of interpreting these deviations is the dissolution of the hydrothermally formed mineral caminite (MgSO4 0.25 Mg (OH)2 0.2H2O). This interpretation is corroborated by a thorough investigation of fluid isotope systems (δ26Mg, δ30Si, δ34S, δ44/42Ca, and 87Sr/86Sr). Caminite is known from mineral assemblages with anhydrite and forms in hydrothermal recharge zones only under specific conditions such as high fluid temperatures and in altered oceanic crust, which are conditions generally met at the TR. We hypothesize that caminite was formed during hydrothermal activity and is now dissolving during the waning state of the hydrothermal system, so that caminite mineralization is shifted out of its stability zone. Ongoing fluid circulation through the basement is transporting the geochemical signal via slow advection toward the seafloor.
KW - Isotope ratio
KW - Delta value
KW - Pore fluids
KW - Magnesium
KW - Hydrothermal fluid
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503430
DO - https://doi.org/10.1029/2019GC008525
VL - 20
IS - 12
SP - 6078
EP - 6094
PB - Wiley
AN - OPUS4-50343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Jonathan
A1 - Merz, Benjamin
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Surface structure analysis using visual high-resolution in situ process monitoring in laser powder bed fusion
N2 - Parameter studies are a common step in selecting process parameters for laser powder bed fusion of metals (PBF-LB/M). Density cubes are commonly used for this purpose. Density cubes manufactured with varied process parameters can exhibit distinguishable surface structures visible to the human eye. The layer-wise process enables such surface structures to be detected during manufacturing. However, industrial visual in situ monitoring systems for PBF-LB/M currently have limited resolution and are incapable of reliably capturing small differences in the surface structures. In this work, a 65 MPixel high-resolution monochrome camera was integrated into an industrial PBF-LB/M machine together with a high-intensity LED (light-emitting diode) bar. Post-exposure images were taken to analyse differences in light reflection of fused areas. It is revealed that the grey-level co-occurrence matrix can be used to quantify the visual surface structure of nickel-based superalloy Inconel®939 density cubes per layer. The properties of the grey-level co-occurrence matrix correlate to the energy input and the resulting porosity of density cubes. Low-energy samples containing lack of fusion flaws show an increased contrast in the grey-level co-occurrence matrix compared to specimens with optimal energy input. The potential of high-resolution images for quality assurance via in situ process monitoring in PBF-LB/M is further discussed.
KW - Additive manufacturing
KW - Powder bed fusion
KW - In situ monitoring
KW - Image processing
KW - High resolution camera
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626685
DO - https://doi.org/10.1007/s40194-025-01955-1
SN - 1878-6669
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-62668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Selina B. I.
A1 - Täschner, Tom
A1 - Nordholt, Niclas
A1 - Schreiber, Frank
T1 - Differential Selection for Survival and for Growth in Adaptive Laboratory Evolution Experiments With Benzalkonium Chloride
N2 - Biocides are used to control microorganisms across different applications, but emerging resistance may pose risks for those applications. Resistance to biocides has commonly been studied using adaptive laboratory evolution (ALE) experiments with growth at subinhibitory concentrations linked to serial subculturing. It has been shown recently that Escherichia coli adapts to repeated lethal stress imposed by the biocide benzalkonium chloride (BAC) by increased survival (i.e., tolerance) and not by evolving the ability to grow at increased concentrations (i.e., resistance). Here, we investigate the contributions of evolution for tolerance as opposed to resistance for the outcome of ALE experiments with E. coli exposed to BAC. We find that BAC concentrations close to the half maximal effective concentration (EC50, 4.36 μg mL−1) show initial killing (~40%) before the population resumes growth. This indicates that cells face a two‐fold selection pressure: for increased survival and for increased growth. To disentangle the effects of both selection pressures, we conducted two ALE experiments: (i) one with initial killing and continued stress close to the EC50 during growth and (ii) another with initial killing and no stress during growth. Phenotypic characterization of adapted populations showed that growth at higher BAC concentrations was only selected for when BAC was present during growth. Whole genome sequencing revealed distinct differences in mutated genes across treatments. Treatments selecting for survival‐only led to mutations in genes for metabolic regulation (cyaA) and cellular structure (flagella fliJ), while treatments selecting for growth and survival led to mutations in genes related to stress response (hslO and tufA). Our results demonstrate that serial subculture ALE experiments with an antimicrobial at subinhibitory concentrations can select for increased growth and survival. This finding has implications for the design of ALE experiments to assess resistance risks of antimicrobials in different scenarios such as disinfection, preservation, and environmental pollution.
KW - Antimicrobial resistance
KW - Bacteria
KW - Standardization
KW - Biocides
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615496
DO - https://doi.org/10.1111/eva.70017
VL - 17
IS - 10
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-61549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Stephan
A1 - Hoffmann, Holger
A1 - Garbe, Leif-Alexander
A1 - Harrer, Andrea
A1 - Steiner, Markus
A1 - Himly, Martin
A1 - Schneider, Rudolf
T1 - Re-assessment of monoclonal antibodies against diclofenac for their application in the analysis of environmental waters
N2 - The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is an important environmental contaminant occurring in surface waters all over the world, because, after excretion, it is not adequately removed from wastewater in sewage treatment plants. To be able to monitor this pollutant, highly efficient analytical methods are needed, including immunoassays. In a medical research project, monoclonal antibodies against diclofenac and its metabolites had been produced. Based on this monoclonal anti-DCF antibody, a new indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed and applied for environmental samples. The introduction of a spacer between diclofenac and the carrier protein in the coating conjugate led to higher sensitivity. With a test midpoint of 3 mg L−1 and a measurement range of 1–30 mg L−1, the system is not sensitive enough for direct analysis of surface water. However, this assay is quite robust against matrix influences and can be used for wastewater. Without adjustment of the calibration, organic solvents up to 5%, natural organic matter (NOM) up to 10 mg L−1, humic acids up to 2.5 mg L−1, and salt concentrations up to 6 g L−1 NaCl and 75 mg L−1 CaCl2 are tolerated. The antibody is also stable in a pH range from 3 to 12. Cross-reactivity (CR) of 1% or less was determined for the metabolites 40-hydroxydiclofenac (40-OH-DCF), 5-hydroxydiclofenac (5-OH-DCF), DCF lactam, and other NSAIDs. Relevant cross-reactivity occurred only with an amide derivative of DCF, 6-aminohexanoic acid (DCF-Ahx), aceclofenac (ACF) and DCF methyl ester (DCF-Me) with 150%, 61% and 44%, respectively. These substances, however, have not been found in samples. Only DCF-acyl glucuronide with a cross-reactivity of 57% is of some relevance. For the first time, photodegradation products were tested for cross-reactivity. With the ELISA based on this antibody, water samples were analysed. In sewage treatment plant effluents, concentrations in the range of 1.9–5.2 mg L−1 were determined directly, with recoveries compared to HPLC-MS/MS averaging 136%.
Concentrations in lakes ranged from 3 to 4.4 ng L−1 and were, after pre-concentration, determined with an average recovery of 100%
KW - Antikörper
KW - Immunoassay
KW - Wasser
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602280
DO - https://doi.org/10.1039/d3ay01333b
VL - 16
IS - 21
SP - 3349
EP - 3363
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-60228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Wolfram
A1 - Kanjee, J.
A1 - Motukwa, G.
A1 - Olonade, K.
A1 - Dodoo, A.
T1 - A snapshot review of future‑oriented standards for cement, admixtures, and concrete: How Africa can spearhead the implementation of green urban construction materials
N2 - The existing cement and concrete standards are not capable of making full use of the current technology capacity due to strong focus on conventional concrete and thus they are not fit for the current and future challenges of construction industry. The paper highlights shortcomings with regard to the implementation of the existing standards. It can be seen that future-oriented standards are generally required to contribute to a lower-carbon footprint of the industry. These changes are significantly more relevant in sub-Saharan Africa, due to the rapidly increasing urbanisation challenge and the enormous potentials to develop lower-carbon technologies than elsewhere in the world.
KW - Future‑oriented standards
KW - Green urban construction
KW - Cement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582563
DO - https://doi.org/10.1557/s43580-023-00563-9
SN - 2731-5894
VL - 4
IS - 8
SP - 557
EP - 565
PB - Springer International Publishing
CY - Springer Nature Switzerland, Cham
AN - OPUS4-58256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Wolfram
A1 - Tchetgnia Ngassam, Ines Leana
A1 - Olonade, K. A.
A1 - Mbugua, R.
A1 - Kühne, Hans-Carsten
T1 - Plant based chemical admixtures – potentials and effects on the performance of cementitious materials
N2 - While today, engineers can choose from a wide range of rheology modifying admixtures, in some parts of the world, these are difficult to access, due to their complex processing. However, alternatives can be bio‐based polymers such as polysaccharides from various sources. These are easily accessible all over the world, do not demand for complicated processing, and typically they are more sustainable than many established materials, which are crude oil‐based.
The paper presents the effects of acacia gum, cassava starch and the gum of triumfetta pendrata A. Rich on the rheological performance of cementitious systems. It is shown that acacia gum can be as efficient as polycarboxylate based superplasticisers, cassava starch can reduce the yield stress slightly with little effect on the plastic viscosity, and the gum of triumfet ta pendrata A. Rich increases the thixotropy of cement pastes with plasticizing polymers significantly.
KW - Polysaccharides
KW - Rheology
KW - Cement
KW - Chemical admixtures
KW - Bio-based concrete
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476748
DO - https://doi.org/10.21809/rilemtechlett.2018.83
VL - 3
SP - 124
EP - 128
PB - RILEM S.A.R.L.
CY - Paris
AN - OPUS4-47674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmolke, Tobias
A1 - Brunner-Schwer, Christian
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - On welding of high-strength steels using laser beam welding and resistance spot weld bonding with emphasis on seam leak tightness
N2 - The design of most electric vehicles provides for the positioning of the heavy energy storage units in the underbody of the cars. In addition to crash safety, the battery housing has to meet high requirements for gas tightness. In order to test the use of high-strength steels for this sub-assembly, this paper examines welded joints utilizing resistance spot weld bonding and laser remote welding, with special regard to the gas tightness of the welds. For this purpose, the pressure difference test and helium sniffer leak detection are presented and applied. The combination of both leak test methods has proven ideal in experimental investigations. For laser remote welding, gas-tight seams can be achieved with an inter-sheet gap of 0.1 mm, even if occasionally leaking samples cannot be prevented. Resistance spot welding suits gas-tight joining with both one- and two-component adhesives. Against the background of leak tightness, process fluctuations that lead to weld spatter and defects in the adhesive layer must be prevented with high priority.
KW - Resistance spot weld bonding
KW - Laser welding
KW - Seam leak tightness
KW - High-strength steel
KW - Leak testing
KW - Helium sniffer leak detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624250
DO - https://doi.org/10.3390/jmmp7030116
SN - 2504-4494
VL - 7
IS - 3
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-62425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Micromonospora aurantiaca Strain G9, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G9 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G9 was assigned to the species Micromonospora aurantiaca.
KW - Polyethylene
KW - Micromonospora aurantiaca
KW - Degradation
KW - iChip
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547181
DO - https://doi.org/10.1128/mra.01148-21
SN - 2576-098X
VL - 11
IS - 5
SP - 1
EP - 2
PB - American Society for Microbiology
CY - Washington, DC
AN - OPUS4-54718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Pseudomonas veronii Strain G2, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G2 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G2 was assigned to the species Pseudomonas veronii.
KW - Polyethylene
KW - Next generation sequencing
KW - Pseudomonas veronii
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548973
DO - https://doi.org/10.1128/mra.00365-22
SP - 1
EP - 2
PB - ASM
AN - OPUS4-54897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Cupriavidus campinensis Strain G5, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G5 was determined by PacBio sequencing. Using the TYGS for taxonomic classification, strain G5 was assigned to the species Cupriavidus campinensis.
KW - Polyethylene
KW - Cupriavidus campinensis
KW - Plastic degradation
KW - Genome sequence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557897
DO - https://doi.org/10.1128/mra.00553-22
SP - 1
EP - 2
PB - ASM
AN - OPUS4-55789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, Friedhelm
A1 - Remus, Daniela
A1 - Dyall-Smith, Mike
A1 - Kunte, Hans-Jörg
ED - Klepac-Ceraj, Vanja
T1 - Genome sequence of Pseudomonas silesiensis strain G3, a member of a bacterial consortium capable of polyethylene degradation
N2 - A consortium of landfill bacteria including strain G3 can break down polyethylene, a long-lasting plastic that accumulates in the environment. The complete genome sequence of strain G3 was determined by PacBio and Nanopore sequencing and consists of three circular replicons. Genome-based classification assigned strain G3 to the species Pseudomonas silesiensis.
KW - PE degradation
KW - Polyethylene
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611618
DO - https://doi.org/10.1128/mra.00138-24
SN - 2576-098X
VL - 13
IS - 11
SP - 1
EP - 3
PB - American Society for Microbiology
AN - OPUS4-61161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, J.
A1 - Farris, L.
A1 - Nolze, Gert
A1 - Reinsch, Stefan
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Thompson, S.
T1 - Microstructure evolution in Inconel 718 produced by powder bed fusion additive manufacturing
N2 - Inconel 718 is a precipitation strengthened, nickel-based super alloy of interest for the Additive Manufacturing (AM) of low volume, complex parts to reduce production time and cost compared to conventional subtractive processes. The AM process involves repeated rapid melting, solidification and reheating, which exposes the material to non-equilibrium conditions that affect elemental segregation and the subsequent formation of solidification phases, either beneficial or detrimental. These variations are difficult to characterize due to the small length scale within the micron sized melt pool. To understand how the non-equilibrium conditions affect the initial solidification phases and their critical temperatures, a multi-length scale, multi modal approach has been taken to evaluate various methods for identifying the initial phases formed in the as-built Inconel 718 produced by laser-powder bed fusion (L-PBF) additive manufacturing (AM). Using a range of characterization tools from the bulk differential thermal analysis (DTA) and x-ray diffraction (XRD) to spatially resolved images using a variety of electron microscopy tools, a better understanding is obtained of how these minor phases can be properly identified regarding the amount and size, morphology and distribution. Using the most promising characterization techniques for investigation of the as-built specimens, those techniques were used to evaluate the specimens after various heat treatments. During the sequence of heat treatments, the initial as-built dendritic structures recrystallized into well-defined grains whose size was dependent on the temperature. Although the resulting strength was similar in all heat treated specimens, the elongation increased as the grain size was refined due to differences in the precipitated phase distribution and morphology.
KW - Metal additive manufacturing
KW - Inconel 718
KW - Heat treatment
KW - Grain boundary precipitates
KW - Laves phase
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542758
DO - https://doi.org/10.3390/jmmp6010020
SN - 2504-4494
VL - 6
IS - 1
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-54275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Mike
A1 - Couzinié, Jean-Philippe
A1 - Shalabi, Amin
A1 - Ibrahimkhel, Farhad
A1 - Ferrari, Alberto
A1 - Körmann, Fritz
A1 - Laplanche, Guillaume
T1 - Effect of stacking fault energy on the thickness and density of annealing twins in recrystallized FCC medium and high-entropy alloys
N2 - This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and recrystallized to obtain different grain sizes. This work thus provides a database that could be used for data mining to take twin boundary engineering for alloy development to the next level. Since the stacking fault energy is known to strongly affect recrystallized microstructures, the latter was determined at 293 K using the weak beam dark-field technique and compared with ab initio simulations, which additionally allowed to calculate its temperature dependence. Finally, we show that all these data can be rationalized based on theories and empirical relationships that were proposed for pure metals and binary Cu-based alloys.
KW - CoCrFeMnNi HEAs and MEAs
KW - Recrystallization
KW - Transmission electron microscopy (TEM)
KW - Electron backscatter diffraction
KW - Grain boundary engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629346
DO - https://doi.org/10.1016/j.scriptamat.2023.115844
SN - 1359-6462
VL - 240
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Ralf
A1 - Weigert, Florian
A1 - Lesnyak, V.
A1 - Leubner, S.
A1 - Lorenz, T.
A1 - Behnke, Thomas
A1 - Dubavik, A.
A1 - Joswig, J.-O.
A1 - Resch-Genger, Ute
A1 - Gaponik, N.
A1 - Eychmüller, A.
ED - Resch-Genger, Ute
ED - Schneider, Ralf
T1 - pH and concentration dependence of the optical properties of thiol-capped CdTe nanocrystals in water and D2O
N2 - The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical composition and thickness of inorganic passivation shells and the chemical nature and number of surface ligands as well as the strength of their bonds to surface atoms.
The latter is particularly important for CdTe NCs, which – together with alloyed CdₓHg₁₋ₓTe – are the only SC NCs that can be prepared in water in high quality without the need for an additional inorganic passivation shell. Aiming at a better understanding of the role of stabilizing ligands for the control of the application-relevant fluorescence features of SC NCs, we assessed the influence of two of the most commonly used monodentate thiol ligands, thioglycolic acid (TGA) and mercaptopropionic acid (MPA),
on the colloidal stability, photoluminescence (PL) quantum yield (QY), and PL decay behavior of a set of CdTe NC colloids. As an indirect measure for the strength of the coordinative bond of the ligands to SC NC surface atoms, the influence of the pH (pD) and the concentration on the PL properties of these colloids was examined in water and D₂O and compared to the results from previous dilution studies with a set of thiol-capped Cd₁₋ₓHgₓTe SC NCs in D₂O. As a prerequisite for these studies, the number of surface ligands was determined photometrically at different steps of purification after SC NC synthesis with Ellman’s test.
Our results demonstrate ligand control of the pH-dependent PL of these SC NCs, with MPA-stabilized CdTe NCs being less prone to luminescence quenching than TGA-capped ones. For both types of CdTe colloids, ligand desorption is more pronounced in H₂O compared to D₂O, underlining also the role of hydrogen bonding and solvent molecules.
KW - Quantum dots
KW - Fluorescence
KW - Ligand analysis
KW - Nano particles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371253
DO - https://doi.org/10.1039/c6cp03123d
VL - 18
IS - 28
SP - 19083
EP - 19092
PB - RSC
CY - Cambridge
AN - OPUS4-37125
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 - Schnell, Alexander
A1 - Rübner, Katrin
A1 - Seher, Julia
A1 - Müller, Constanze
A1 - Müller, Anette
A1 - Liebezeit, Steffen
A1 - Fenner, Jacob
A1 - Martin, Falk
A1 - Pniok, Nicole
T1 - Manufacturing and Application of Lightweight Aggregates from Construction and Demolition Waste
N2 - The objective of the REALight project is the development of a thermal process to produce lightweight aggregates in pilot scale and the implantation of a method to recover gypsum. Beside construction and demolition waste, various industrial by‐products are studied as raw materials. The raw materials have so far been unused or used in applications with lower quality requirements. To prove the performance of the lightweight aggregates, their technical properties are tested and their use in different applications is studied, e.g., for lightweight mortars as well as lightweight concretes.
KW - Construction and demolition waste
KW - Flue gas desulfurization gypsum
KW - Industrial by-products
KW - Infra-lightweight concrete
KW - Lightweight aggregates
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604643
DO - https://doi.org/10.1002/cite.202300211
SN - 0009-286X
VL - 96
IS - 7
SP - 969
EP - 975
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-60464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schnur, C.
A1 - Goodarzi, P.
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Prager, Jens
A1 - Tschöke, K.
A1 - Moll, J.
A1 - Schütze, A.
A1 - Schneider, T.
T1 - Towards interpretable machine learning for automated damage detection based on ultrasonic guided waves
N2 - Data-driven analysis for damage assessment has a large potential in structural health monitoring (SHM) systems, where sensors are permanently attached to the structure, enabling continuous and frequent measurements. In this contribution, we propose a machine learning (ML) approach for automated damage detection, based on an ML toolbox for industrial condition monitoring. The toolbox combines multiple complementary algorithms for feature extraction and selection and automatically chooses the best combination of methods for the dataset at hand. Here, this toolbox is applied to a guided wave-based SHM dataset for varying temperatures and damage locations, which is freely available on the Open Guided Waves platform. A classification rate of 96.2% is achieved, demonstrating reliable and automated damage detection. Moreover, the ability of the ML model to identify a damaged structure at untrained damage locations and temperatures is demonstrated.
KW - Composite structures
KW - Structural health monitoring
KW - Carbon fibre-reinforced plastic
KW - Interpretable machine learning
KW - Automotive industry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542060
DO - https://doi.org/10.3390/s22010406
SN - 1424-8220
VL - 22
IS - 1
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-54206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Drescher, P.
A1 - Fischer, M.
A1 - Fürhapper, C.
A1 - Gunschera, J.
A1 - Hill, R.
A1 - Melcher, E.
A1 - Wegner, R.
A1 - Wilken, U.
A1 - Wittenzellner, J.
T1 - Suitability of analytical methods to determine tebuconazole, propiconazole and permethrin in aged wood samples
N2 - The suitability of common analytical methods for the determination of active substances from wood preservatives in aged wood samples was investigated during an interlaboratory study. Permethrin, propiconazole and tebuconazole were quantified in 1.5 and 8 year-old wood samples by gas chromatography and liquid chromatography. Generally, the applied Methods yielded reliable results for these samples. However, wood components can coelute with propiconazole and tebuconazole during liquid chromatography. Optimization of separation might be required if UV detection is applied.
KW - Wood samples
KW - Biocides
KW - Analytical methods
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503959
DO - https://doi.org/10.1007/s00107-020-01496-y
VL - 78
IS - 2
SP - 271
EP - 279
PB - Springer
CY - Heidelberg
AN - OPUS4-50395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Kalbe, Ute
A1 - Heisterkamp, I.
A1 - Kretzschmar, M.
A1 - Gartiser, S.
A1 - Happel, O.
A1 - Ilvonen, O.
T1 - Release of substances from joint grouts based on various binder types and their ecotoxic effects
N2 - Background: The leaching of substances and the ecotoxic effects of eluates were studied for joint grouts that are based on various types of binders. Eight products, two of them containing either epoxy resin, polybutadiene or polyurethane binders, or modifed cement, were investigated using harmonized leaching tests for construction products in combination with ecotoxicity tests on algae, daphnia, luminescent bacteria, fish eggs and mutagenicity in accordance with CEN/TR 17105. In addition to basic parameters, such as pH, TOC, and inorganic components, organic substances in the eluates were analysed by gas and liquid chromatography in combination with mass spectrometry. Quantitative analyses in combination with ecotoxicity data on selected substances were used to deduce which substances cause the observed ecotoxic effects.
Results: Different patterns of ecotoxic effects were observed in joint grouts with different binder types. The most ecotoxic effects were observed in epoxy resin-based products, followed by polybutadiene-based products. Fewer ecotoxic effects were observed in polyurethane-based products and modifed cements. Some of these showed no ecotoxicity. Some of the substances in the eluates were identified and related to ecotoxic effects. 4-Tert-butylphenol and amines probably contributed to the ecotoxic effects of at least one of the epoxy resin-based renders, whereas cobalt is assumed to contribute to the toxic effect on algae of one of the polybutadiene-based products. However, only some of the leached substances could be identifed, and only some of the ecotoxic effects can be explained by the available information on the composition of eluates and known ecotoxic profiles of the identified substances.
Conclusions: Ecotoxicity tests on eluates from leaching tests indicate whether environmentally hazardous substances can be leached from construction products. Combined ecotoxicity tests and chemical analysis of eluates from EU-wide harmonized leaching tests for construction products can provide information on substances that cause these effects. This supports the identifcation and development of environmentally friendly construction products.
This study confirmed that ecotoxicity tests in accordance with CEN/TR 17105 are a tool well-suited to support the implementation of the European Commission’s zero pollution vision for 2050 and to reduce pollution to levels no longer considered harmful to health and natural ecosystems.
KW - Joint grouts
KW - Leaching
KW - Ecotoxixity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562392
DO - https://doi.org/10.1186/s12302-022-00686-0
SN - 2190-4707
VL - 34
IS - 1
SP - 1
EP - 16
PB - Springer Nature
CY - Berlin
AN - OPUS4-56239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Kalbe, Ute
A1 - Van Zomeren, A.
A1 - Hjelmar, O.
T1 - Laboratory leaching tests on treated wood according to different harmonised test procedures
N2 - -Background-
Laboratory leaching tests on treated wood were performed during a European robustness study in the framework of the validation of a tank leaching test procedure that has been proposed for construction products in order to determine the potential release of dangerous substances which can be transferred to soil and groundwater. The release of substances has to be determined also for materials treated with biocidal products according to the requirements of the European Biocidal Products Regulation. A similar leaching test procedure was already harmonised for treated wood for this purpose. Both test procedures were applied in parallel to wood treated with the same preservative to investigate whether the results of these tests can replace each other. Additional experiments were performed to further investigate unexpected effects of L/A ratio on leaching of copper and duration of storage of treated test specimens.
-Results-
Both procedures generate similar results concerning cumulative emissions of tebuconazole, copper, dissolved organic carbon and total nitrogen. The emission rates with time are in comparable ranges for both leaching protocols. Emissions of copper increased with decreasing L/A ratios. Strong correlation of copper concentrations and dissolved organic carbon as well as total nitrogen concentrations in eluates indicates that this observation is caused by co-elution of copper with organic substances. Duration of storage of treated test specimens affected emissions for the investigated wood preservative.
-Conclusions-
Based on these findings, results from both test procedures can be used to describe leaching characteristics and avoid double testing of treated wood to fulfil the requirements of the European regulations for either biocides or construction products. Leaching of substances from treated wood is a complex process that depends on its chemical composition and ageing processes.
KW - Construction products
KW - Biocidal product
KW - Emission
KW - Leaching
KW - Tank leaching test
KW - Treated wood
KW - European regulation
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317320
UR - http://www.enveurope.com/content/26/1/25
SN - 2190-4715
SN - 2190-4707
VL - 26
SP - 25, 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-31732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, H.
T1 - The Impact of Weather Conditions on Biocides in Paints
N2 - Weather conditions affect biocides on exposed outer surfaces on constructions. Contact with water causes hydrolysis and leaching of substances. Ultraviolet radiation may induce photolysis. As a result, a mixture of biocidal active substances and transformation products can be emitted into the environment. In a semi-field study, leaching of the biocidal active substances terbutryn, diuron, octylisothiazolinone, carbendazim, and selected transformation products was observed for two paints containing either a white or a red pigment. Painted test panels were exposed to natural weathering for about 1.5 years. Runoff samples were analyzed during the course of the experiment.
At the end of the study, residues of biocidal active substances and transformation products were determined in sections of the test panels. Emissions of substances were mainly observed during the first few months of the experiments. Increased emissions of transformation products were observed during periods of increased global radiation and subsequent periods with relatively high amounts of driving rain. Different patterns of transformation products were observed, especially for terbutryn, both for paints containing different pigments and in experiments that were started in different periods of the year, as well as during different periods of the experiments.
KW - Substance release
KW - Construction products
KW - Biocides
KW - Transformation
KW - Weathering
KW - Driving rain
KW - Global radiation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560651
DO - https://doi.org/10.3390/ma15207368
VL - 15
IS - 20
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-56065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, Helena
A1 - Lisec, Jan
T1 - Leaching and transformation of film preservatives in paints induced by combined exposure to ultraviolet radiation and water contact under controlled laboratory conditions
N2 - Stormwater from urban areas can transport biocidally active substances and related transformation products from buildings into the environment. The occurrence of these substances in urban runoff depends on the availability of water, and on ultraviolet radiation exposure that causes photolytic reactions. In a systematic laboratory study, painted test specimens were exposed to either ultraviolet radiation, water contact, or a combination of both. Leaching of the biocidally active substances carbendazim, diuron, octylisothiazolinone, terbutryn, and selected transformation products of terbutryn and diuron were observed under various exposure conditions. Remaining concentrations of these substances in the paint were quantified. It was demonstrated that the distribution of active substances and transformation products in eluates and in the coatings themselves differs with exposure conditions. Strategies for environmental monitoring of biocide emissions need to consider the most relevant transformation products. However, environmental concentrations of biocidally active substances and transformation products depend on earlier exposure conditions. As a consequence, monitoring data cannot describe emission processes and predict expected leaching of biocidally active substances from buildings if the data are collected only occasionally.
KW - Substance release
KW - Construction products
KW - Biocides
KW - Transformation
KW - UV radiation
KW - Water contact
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532114
DO - https://doi.org/10.3390/w13172390
SN - 2073-4441
VL - 13
IS - 17
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, Helena
A1 - Wegner, R.
T1 - Biocide leaching during field experiments on treated articles
N2 - Background: Biocidal products can be sources of active substances in surface waters caused by weathering of treated articles. Marketing and use of biocidal products can be limited according to the European Biocidal Products Regulation if unacceptable risks to the environment are expected. Leaching of active substances from treated articles was observed in field experiments to obtain information on leaching processes and investigate the suitability of a proposed test method.
Results: Leaching under weathering conditions proceeds discontinuously and tends to decrease with duration of exposure. It mainly depends on the availability of water, but is also controlled by transport processes within the materials and stability of the observed substances. Runoff amount proved to be a suitable basis to compare results from different experiments. Concentrations of substances are higher in runoff collected from vertical surfaces compared to horizontal ones, whereas the leached amounts per surface area are higher from horizontal surfaces. Gaps in mass balances indicate that additional processes such as degradation and evaporation may be relevant to the fate of active substances in treated articles. Leached amounts of substances were considerably higher when the materials were exposed to intermittent water contact under laboratory conditions as compared to weathering of vertically exposed surfaces.
Conclusions: Experiences from the field experiments were used to define parameters of a procedure that is now provided to fulfil requirements of the Biocidal Products Regulation. The experiments confirmed that the amount of water which is in contact with exposed surfaces is the crucial parameter determining leaching of substances.
KW - Biozidprodukte
KW - Farben
KW - Textil
KW - Auswaschung
KW - Freilandtest
KW - Biocidal products
KW - Paints
KW - Textile
KW - Leaching
KW - Field test
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354090
DO - https://doi.org/10.1186/s12302-016-0074-9
VL - 28
IS - 6
SP - 1
EP - 10
PB - Springer
CY - SpringerOpen
AN - OPUS4-35409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Tietje, O.
A1 - Borho, N.
A1 - Burkhardt, M.
A1 - Rohr, M.
A1 - Vollpracht, A.
A1 - Weiler, L.
T1 - Environmental impact of construction products on aquatic systems - Principles of an integrated source-path-target concept
N2 - Buildings exposed to water can release undesirable substances which, once transported to environmental compartments, may cause unwanted effects. These exposure pathways need to be investigated and included in risk assessments to safeguard water quality and promote the sustainability of construction materials. The applied materials, exposure conditions, distribution routes and resilience of receiving compartments vary considerably. This demonstrates the need for a consistent concept that integrates knowledge of emission sources, leaching processes, transport pathways, and effects on targets. Such a consistent concept can serve as the basis for environmental risk assessment for several scenarios using experimentally determined emissions. Typically, a source–path–target concept integrates data from standardized leaching tests and models to describe leaching processes, the distribution of substances in the environment and the occurrence of substances at different points of compliance. This article presents an integrated concept for assessing the environmental impact of construction products on aquatic systems and unravels currently existing gaps and necessary actions. This manuscript outlines a source–path–target concept applicable to a large variety of construction products. It is intended to highlight key elements of a holistic evaluation concept that could assist authorities in developing procedures for environmental risk assessments and mitigation measures and identifying knowledge gaps.
KW - Construction products
KW - Environmental impact
KW - Assessment
KW - Concept
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542175
DO - https://doi.org/10.3390/w14020228
SN - 2073-4441
VL - 14
IS - 2
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-54217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholl, Juliane
A1 - Lisec, Jan
A1 - Bagheri, Abbas
A1 - Meiers, Emelie
A1 - Russo, Francesco Friedrich
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Unveiling aging mechanisms of electrolytes in commercial end-of-life lithium-ion batteries
N2 - In this study, 77 end-of-life (EOL) commercial lithium-ion batteries (LIBs) of various formats were systematically analyzed to investigate electrolyte degradation and the influence of pristine electrolyte compositions on aging behavior. Comprehensive chemical characterization was conducted using targeted and non-targeted mass spectrometry (MS), employing LC-MS/MS, GC-MS, and high-resolution MS (HRMS). This integrated approach enabled the identification of confirmed pristine components and complex degradation products. The results show that rechargeable pouch and cylindrical cells often deviate from conventional model systems, containing mixed lithium salt anions, ionic liquids (ILs), and high concentrations of triflates, triflimides, and bis(fluorosulfonyl)imide (FSI). These function as solvents, salts, or safety-enhancing additives. Specific IL degradation products were identified, and hypotheses formulated on previously unreported pathways. Furthermore, a novel series of oligomerization products of propylene carbonate (PC) was detected. In contrast, non-rechargeable coin cells revealed widespread use of per- and polyfluoroalkyl substances (PFAS) in their original electrolytes. Based on ex situ analyses, hypothetical PFAS degradation mechanisms are proposed here for the first time. The absence of carbonate oligomers and lithium salt-derived products, alongside the presence of standard carbonates, indicates lithium counterion coordination as a key factor in Lewis acid-catalyzed degradation. This study offers valuable insights into real-world battery aging.
KW - Transformation products
KW - Lithium-ion batteries
KW - Fluorinated Compounds
KW - Gas chromatography/ QTOF-MS
KW - HILIC-LC-MS/MS
KW - PFAS
KW - Electrochemistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644991
DO - https://doi.org/10.1016/j.jpowsour.2025.238613
SN - 0378-7753
VL - 661
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-64499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholl, Juliane
A1 - Lisec, Jan
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Identification of transformation products from fluorinated lithium-ion battery additives TPFPB and TPFPP: forever chemicals of tomorrow?
N2 - AbstractFluorinated organic compounds (FOCs) represent a class of synthetic chemicals distinguished by their resilient carbon–fluorine bonds, which demonstrate an ability to withstand environmental degradation over an extended period. The integration of FOCs into cutting-edge applications, including lithium-ion batteries (LiBs), presents considerable potential for environmental harm that has not yet been sufficiently addressed. This study focuses on the environmental fate of two fluorinated aromatics, tris(pentafluorophenyl)borane (TPFPB) and tris(pentafluorophenyl)phosphine (TPFPP), given their important role in improving the performance of LiBs. To achieve this, laboratory simulation methods including total oxidizable precursor assay, electrochemistry (EC), Fenton reaction, UV-C irradiation, and hydrolysis were employed. Liquid chromatography and gas chromatography coupled with high-resolution mass spectrometry were used for identification of transformation products (TPs) and prediction of their molecular formulae. Despite the structural similarity between TPFPB and TPFPP, distinct differences in electrochemical behavior and degradation pathways were observed. TPFPB readily underwent hydroxylation and hydrolysis, resulting in a wide range of 49 TPs. A total of 28 TPs were newly identified, including oligomers and highly toxic dioxins. In contrast, TPFPP degraded exclusively under harsh conditions, requiring the development of innovative conditioning protocols for EC. In total, the simulation experiments yielded nine structurally different compounds, including seven previously undescribed, partially defluorinated TPs. This study highlights the potential risks associated with the use of FOCs in LiBs and provides insight into the complex environmental behavior of FOCs.
KW - Mass Spectrometry
KW - LiBs
KW - POPs
KW - Transformation products
KW - Electrochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611339
DO - https://doi.org/10.1007/s00216-024-05526-z
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-61133
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, G.
A1 - Staude, Andreas
A1 - Dunlop, J.A.
T1 - Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities
N2 - Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.
KW - Trilobite compound eyes
KW - Computed Tomography
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510784
DO - https://doi.org/10.1038/s41467-019-10459-8
SN - 2041-1723
VL - 10
SP - 2503
PB - Nature
AN - OPUS4-51078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Eckert, J. G.
A1 - Elahi, T.
A1 - Lübkemann, F.
A1 - Hübner, Oskar
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Luminescence encoding of polymer microbeads with organic dyes and semiconductor quantum dots during polymerization
N2 - Luminescence-encoded microbeads are important tools for many applications in the life and material sciences that utilize luminescence detection as well as multiplexing and barcoding strategies. The preparation of such beads often involves the staining of premanufactured beads with molecular luminophores using simple swelling procedures or surface functionalization with layer-by-layer (LbL) techniques. Alternatively, these luminophores are sterically incorporated during the polymerization reaction yielding the polymer beads. The favorable optical properties of semiconductor quantum dots (QDs), which present broadly excitable, size-tunable, narrow emission bands and low photobleaching sensitivity, triggered the preparation of beads stained with QDs. However, the colloidal nature and the surface chemistry of these QDs, which largely controls their luminescence properties, introduce new challenges to bead encoding that have been barely systematically assessed. To establish a straightforward approach for the bead encoding with QDs with minimized loss in luminescence, we systematically assessed the incorporation of oleic acid/oleylamine-stabilized CdSe/CdS-core/shell-QDs into 0.5–2.5 μm-sized polystyrene (PS) microspheres by a simple dispersion polymerization synthesis that was first optimized with the organic dye Nile Red. Parameters addressed for the preparation of luminophore-encoded beads include the use of a polymer-compatible ligand such as benzyldimethyloctadecylammonium chloride (OBDAC) for the QDs, and crosslinking to prevent luminophore leakage. The physico-chemical and optical properties of the resulting beads were investigated with electron microscopy, dynamic light scattering, optical spectroscopy, and fluorescence microscopy. Particle size distribution, fluorescence quantum yield of the encapsulated QDs, and QD leaking stability were used as measures for bead quality. The derived optimized bead encoding procedure enables the reproducible preparation of bright PS microbeads encoded with organic dyes as well as with CdSe/CdS-QDs. Although these beads show a reduced photoluminescence quantum yield compared to the initially very strongly luminescent QDs, with values of about 35%, their photoluminescence quantum yield is nevertheless still moderate.
KW - Polymerization
KW - Quantum dots
KW - Microbeads
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553430
DO - https://doi.org/10.1038/s41598-022-16065-x
SN - 2045-2322
VL - 12
SP - 1
EP - 16
PB - Nature Publishing Group
CY - London
AN - OPUS4-55343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Eckert, J. G.
A1 - Lutowski, Marc
A1 - Geißler, Daniel
A1 - Hertwig, Andreas
A1 - Hidde, Gundula
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Influence of nanoparticle encapsulation and encoding on the surface chemistry of polymer carrier beads
N2 - Surface-functionalized polymer beads encoded with molecular luminophores and nanocrystalline emitters such as semiconductor nanocrystals, often referred to as quantum dots (QDs), or magnetic nanoparticles are broadly used in the life sciences as reporters and carrier beads. Many of these applications require a profound knowledge of the chemical nature and total number of their surface functional groups (FGs), that control bead charge, colloidal stability, hydrophobicity, and the interaction with the environment and biological systems. For bioanalytical applications, also the number of groups accessible for the subsequent functionalization with, e.g., biomolecules or targeting ligands is relevant. In this study, we explore the influence of QD encoding on the amount of carboxylic acid (COOH) surface FGs of 2 μm polystyrene microparticles (PSMPs). This is done for frequently employed oleic acid and oleylamine stabilized, luminescent core/shell CdSe QDs and two commonly used encoding procedures. This included QD addition during bead formation by a thermally induced polymerization reaction and a post synthetic swelling procedure. The accessible number of COOH groups on the surface of QD-encoded and pristine beads was quantified by two colorimetric assays, utilizing differently sized reporters and electrostatic and covalent interactions. The results were compared to the total number of FGs obtained by a conductometric titration and Fourier transform infrared spectroscopy (FTIR). In addition, a comparison of the impact of QD and dye encoding on the bead surface chemistry was performed. Our results demonstrate the influence of QD encoding and the QD-encoding strategy on the number of surface FG that is ascribed to an interaction of the QDs with the carboxylic acid groups on the bead surface. These findings are of considerable relevance for applications of nanoparticle-encoded beads and safe-by-design concepts for nanomaterials.
KW - Optical spectroscopy
KW - Particle
KW - Optical assay
KW - IR spectroscopy
KW - Fluorescence
KW - Quantum yield
KW - Quality assurance
KW - Nano
KW - Synthesis
KW - Surface chemistry
KW - Quantification
KW - Method
KW - Conductometry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581502
DO - https://doi.org/10.1038/s41598-023-38518-7
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 15
PB - Springer Nature
CY - London
AN - OPUS4-58150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholz, Philipp
A1 - Falkenhagen, Jana
A1 - Wachtendorf, Volker
A1 - Brüll, Robert
A1 - Simon, Franz-Georg
T1 - Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
N2 - Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.
KW - Geotextiles
KW - Microplastic
KW - Size exclusion chromatography
KW - Accelerated aging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599739
DO - https://doi.org/10.3390/su16093559
SN - 2071-1050
VL - 16
IS - 9
SP - 1
EP - 15
PB - MDPI AG
CY - Basel
AN - OPUS4-59973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -