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 -