TY - JOUR A1 - Völker, Tobias A1 - Mensing, Friedrich A1 - Kruschwitz, Sabine T1 - Estimation of cement content in concrete by spatially resolved laser induced breakdown spectroscopy N2 - The cement content in concrete significantly influences critical properties such as durability, permeability, strength, and workability. Traditional methods for estimating the cement content face limitations. These include the need for comprehensive chemical and solubility knowledge, extensive sample preparation, and their time-consuming and destructive nature. This study investigates the application of laser-induced breakdown spectroscopy (LIBS) as an alternative method. It involves probing concrete samples with high spatial resolution and analyzing the resultant spectra. The methodology is first tested on mesoscale concrete models to assess limitations and inherent errors. Subsequently, the methodology is applied to actual concrete samples with varying cement content and aggregate size distributions. The results demonstrate a promising accuracy, with an average relative error of approximately 8%. This paper offers a comprehensive evaluation of the method's advantages, limitations, and factors influencing its practical applicability in field conditions. KW - LIBS KW - Spectroscopy KW - Cement content KW - Elemental mapping PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620112 DO - https://doi.org/10.1016/j.cemconres.2024.107714 SN - 1873-3948 VL - 189 SP - 1 EP - 10 PB - Elsevier Ltd. AN - OPUS4-62011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alem, Sayed Ali Ahmad A1 - Sabzvand, Mohammad Hossein A1 - Govahi, Parnian A1 - Poormehrabi, Pooria A1 - Azar, Mahdi Hasanzadeh A1 - Siouki, Sara Salehi A1 - Rashidi, Reza A1 - Angizi, Shayan A1 - Bagherifard, Sara T1 - Advancing the next generation of high-performance metal matrix composites through metal particle reinforcement N2 - Metal matrix composites (MMCs) offer asignificant boost to achieve a wide range of advanced mechanical properties and improved performance for a variety of demanding applications. The addition of metal particles as reinforcement in MMCs is an exciting alternative to conventional ceramic reinforcements, which suffer from numerous shortcomings. Over the last two decades, various categories of metal particles, i.e., intermetallics, bulk metallic glasses, high-entropy alloys, and shape memory alloys, have become popular as reinforcement choices for MMCs. These groups of metal particles offer a combination of outstanding physico-mechanical properties leading to unprecedented performances; moreover, they are significantly more compatible with the metal matrices compared to traditional ceramic reinforcements. In this review paper, the recent developments in MMCs are investigated. The importance of understanding the active mechanisms at the interface of the matrix and the reinforcement is highlighted. Moreover, the processing techniques required to manufacture high-performance MMCs are explored identifying the potential structural and functional applications. Finally, the potential advantages and current challenges associated with the use of each reinforcement category and the future developments are critically discussed. Based on the reported results, the use of metal particles as reinforcement in MMCs offers a promising avenue for the development of advanced materials with novel mechanical properties. Further progress requires more in-depth fundamental research to realize the active reinforcing mechanisms at the atomic level to precisely identify, understand, and tailor the properties of the integrated composite materials. KW - Intermetallic KW - Composite KW - Metal matrix composite KW - Interface KW - High entropy alloy KW - Bulk metallic glass PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620730 DO - https://doi.org/10.1007/s42114-024-01057-4 SN - 2522-0128 VL - 8 IS - 1 SP - 1 EP - 68 PB - Springer Nature AN - OPUS4-62073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saeidfirozeh, H. A1 - Kubelík, P. A1 - Laitl, V. A1 - Krivkova, A. A1 - Vrabel, J. A1 - Rammelkamp, K. A1 - Schroder, S. A1 - Gornushkin, Igor B. A1 - Kepes, E. A1 - Zabka, J. A1 - Ferus, M. A1 - Porízka, P. A1 - Kaiser, J. T1 - Laser-induced breakdown spectroscopy in space applications: Review and prospects N2 - This review describes the principles and summarizes the challenges of analytical methods based on optical emission spectroscopy (OES) in space applications, with a particular focus on Laser-Induced Breakdown Spectroscopy (LIBS). Over the past decade, LIBS has emerged as a powerful analytical technique for space exploration and In-Situ Resource Utilization (ISRU) of celestial bodies. Its implementation has been suggested for various segments of the Space Resources Value Chain, including prospecting, mining, and beneficiation. Current missions to Mars, including the ChemCam instrument on the Curiosity rover, the SuperCam on the Perseverance rover, and the MarSCoDe on the Zhurong rover, are considered flagship applications of LIBS. Despite neither the Pragyan rover nor the Vikram lander waking from the lunar night, the success of the Chandrayaan-3 mission marks another milestone in the development of LIBS instruments, with further missions, including commercial ones, anticipated. This paper reviews the deployment of LIBS payloads on Mars rovers, upcoming missions prospecting the Moon and asteroids, and LIBS analysis of meteorites. Additionally, it highlights the importance of data processing specific to space applications, emphasizing recent trends in transfer learning. Furthermore, LIBS combined with other spectroscopic techniques (e.g., Raman Spectroscopy, Mass Spectrometry, and Fourier-Transform Infrared Spectroscopy) represents an intriguing platform with comprehensive analytical capabilities. The review concludes by emphasizing the significance of LIBS-based contributions in advancing our understanding of celestial bodies and paving the way for future space exploration endeavors KW - Laser-induced breakdown spectroscopy KW - Mars KW - Moon KW - Asteroids KW - Meteorites KW - Machine learning KW - Transfer learning KW - Raman spectroscopy KW - Mass spectrometry KW - Fourier-transform infrared spectroscopy PY - 2024 DO - https://doi.org/10.1016/j.trac.2024.117991 VL - 181 SP - 1 EP - 22 PB - Elsevier B.V. AN - OPUS4-62142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Christensen, J. B. A1 - Jørgensen, A. A. A1 - Vandborg, M. H. A1 - Thomas, P. J. A1 - Lu, Xin A1 - Failleau, G. A1 - Eisermann, R. A1 - Grüner-Nielsen, L. A1 - Balslev-Harder, D. A1 - Lassen, M. A1 - Krenek, S. T1 - Fiber-artefact methodology and calibration framework for Brillouin-based fiber sensing N2 - We propose, and demonstrate, the use of a fiber-optical measurement artefact as a metrological tool for traceable distance calibration of distributed optical fiber sensors. The constructed fiber artefact consists of a lead-in fiber coupled to a fiber loop using a 3-dB coupler and is used to calibrate both a home-build Brillouin-OTDR setup and a custom version of a commercial Brillouin-OTDR interrogator build for distributed temperature sensing. For both interrogators, we demonstrate distance calibrations with 1-meter uncertainty (k=1) in the offset length and 0.1 % (1 m/km) uncertainty (k = 1) in the distance scale factor. In addition, it is shown that the fiber artefact can be used to assess undesired distance-dependent measurement biases. KW - Distributed temperature sensing KW - Metrology KW - Distributed optical fiber sensing KW - Brillouin optical time-domain reflectrometry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618853 DO - https://doi.org/10.1364/OE.544659 SN - 1094-4087 VL - 32 IS - 26 SP - 45483 EP - 45493 PB - Optica Publishing Group AN - OPUS4-61885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shafiey, Hassan A1 - Gogol-Döring, Andreas A1 - McMahon, Dino Peter A1 - Doublet, Vincent A1 - Disayathanoowat, Terd A1 - Paxton, Robert J. T1 - A new variant of slow bee paralysis virus revealed by transcriptome analysis N2 - Using NGS data from an RNA-seq library, we reveal a novel variant of slow bee paralysis virus (SBPV) in a pooled sample of adult honey bees (Apis mellifera) collected in southwest Germany. We provide its sequence (NCBI Accession No. PP100271) and demonstrate that it is infective for adult honey bees by feeding. KW - SBPV KW - Apis mellifera KW - +ss RNA virus KW - Iflaviridae KW - Transmission KW - NGS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620900 DO - https://doi.org/10.1080/00218839.2024.2425912 SP - 1 EP - 5 PB - Taylor & Francis AN - OPUS4-62090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - da Silva, Luiza Helena Bueno A1 - Goes, Aryel C. A1 - Rodrigues, Andre A1 - Fourcassié, Vincent A1 - McMahon, Dino Peter A1 - Haifig, Ives T1 - Social immune response reflects infection progression in a soldierless termite N2 - Social interactions represent a double-edged sword. On one hand, sociality can facilitate sanitary collective behaviours; on the other hand, it creates opportunities for pathogen transmission. In termites, sanitary behaviours can entail a rescuing strategy at early stages of infection, followed by the elimination at later stages. We explored whether the neotropical soldierless species Anoplotermes pacificus employs a progressive approach towards infected nestmates, with different behavioural displays depending on the infection stage. We infected A. pacificus workers with the fungus Metarhizium anisopliae and incubated them for 2, 12, 15 and 20 h, corresponding to infection progression and, therefore, severity. Infected termites were placed with naïve nestmates and their behaviours were recorded for 3 h. Fungus-infected termites triggered up to fourfold higher levels of sanitary behaviour than in non-infected termites. Antennation behaviour decreased during the observation period, whereas sanitary behaviour, which we defined as directed behaviour towards the focal termite involving mouthparts, increased in frequency as incubation duration increased. Sanitary behaviour therefore appears to be a strategy for colony disinfection, which varies in intensity according to infection status, ultimately resulting in the immobilisation of infected individuals at later stages of infection. Alarm responses were also up to three times more frequent in treatment than in control groups and did not vary with incubation duration. A. pacificus workers therefore identify, communicate and respond to pathogen-treated individuals in a progressive manner, indicating that collective responses in this species are also significantly shaped by the stage of infection. By progressively modulating their social immune responses, termites may be able to optimize resource allocation within the colony by balancing the risk of individual infection versus protection of the group. KW - Anoplotermes pacificus KW - Isoptera KW - Infection KW - Metarhizium KW - Social immunity PY - 2024 DO - https://doi.org/10.1007/s00265-024-03556-2 VL - 79 IS - 1 SP - 1 PB - Springer Science and Business Media LLC AN - OPUS4-62397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Mike A1 - Couzinié, Jean-Philippe A1 - Shalabi, Amin A1 - Ibrahimkhel, Farhad A1 - Ferrari, Alberto A1 - Körmann, Fritz A1 - Laplanche, Guillaume T1 - Effect of stacking fault energy on the thickness and density of annealing twins in recrystallized FCC medium and high-entropy alloys N2 - This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and recrystallized to obtain different grain sizes. This work thus provides a database that could be used for data mining to take twin boundary engineering for alloy development to the next level. Since the stacking fault energy is known to strongly affect recrystallized microstructures, the latter was determined at 293 K using the weak beam dark-field technique and compared with ab initio simulations, which additionally allowed to calculate its temperature dependence. Finally, we show that all these data can be rationalized based on theories and empirical relationships that were proposed for pure metals and binary Cu-based alloys. KW - CoCrFeMnNi HEAs and MEAs KW - Recrystallization KW - Transmission electron microscopy (TEM) KW - Electron backscatter diffraction KW - Grain boundary engineering PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629346 DO - https://doi.org/10.1016/j.scriptamat.2023.115844 SN - 1359-6462 VL - 240 SP - 1 EP - 6 PB - Elsevier CY - Amsterdam AN - OPUS4-62934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Kun A1 - Lin, Chang A1 - Pan, Lisha T1 - Effect of sisal fibers on the rheology of cement paste plasticized by polycarboxylate superplasticizer N2 - Sisal fibers (SF) and polycarboxylate superplasticizers (PCE) contribute to the sustainable development of cementitious materials by improving and optimizing their hardening properties. In this study, the impact of SF and PCE on the workability of cement pastes was investigated. The workability was evaluated through spreading diameter, yield stress, and plastic viscosity measurements, and the adsorption behavior of PCE was analyzed. The results showed that the introduction of SF had a negative effect on the workability of PCE plasticized cement pastes, reducing flowability and increasing yield stress and plastic viscosity, regardless of aspect ratio or dosage. A contact angle tester and a scanning electron microscope (SEM) were employed to examine the surface properties of SF. The mechanism behind this interaction of cement-PCE-SF was explored and found to be due to the rough surface of SF, which increased the consumption of PCE, and the formation of hydrogen bonds between PCE and SF. Additionally, PCE modified the interfacial structure between SF and the cement matrix, strengthening the relationship between the different phases. These findings provide new insights into the modification of fiber-reinforced cementitious materials. KW - Cement paste KW - Polycarboxylate KW - Flowability KW - Rheological KW - Sisal fiber (SF) KW - Adsorption PY - 2024 DO - https://doi.org/10.1061/jmcee7.mteng-16789 SN - 0899-1561 VL - 36 IS - 3 SP - 1 EP - 12 PB - American Society of Civil Engineers (ASCE) CY - Reston, VA AN - OPUS4-62893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simbruner, Kai A1 - Billone, Michael C. A1 - Zencker, Uwe A1 - Liu, Yung Y. A1 - Völzke, Holger T1 - Brittle failure analysis and modeling of high-burnup PWR fuel cladding alloys N2 - The aim of this research is the development of methods for predicting mechanical behavior and identification of limiting conditions to prevent brittle failure of high-burnup (HBU) pressure water reactor (PWR) fuel cladding alloys. A finite element (FE) model of the ring compression test (RCT) was created to analyze the failure behavior of zirconium-based alloys with radial hydrides during the RCT. An elastic-plastic material model describes the zirconium alloy. The stress-strain curve needed for the elastic-plastic material model was derived by inverse finite element analyses. Cohesive zone modeling is used to reproduce sudden load drops during RCT loading. Based on the failure mechanism in non-irradiated ZIRLO® claddings, a micro-mechanical model was developed that distinguishes between brittle failure along hydrides and ductile failure of the zirconium matrix. Two different cohesive laws representing these types of failure are present in the same cohesive interface. The key differences between these constitutive laws are the cohesive strength, the stress at which damage initiates, and the cohesive energy, which is the damage energy dissipated by the cohesive zone. Statistically generated matrix-hydride distributions were mapped onto the cohesive elements and simulations with focus on the first load drop were performed. Computational results are in good agreement with the RCT results conducted on high-burnup M5® samples. It could be shown that crack initiation and propagation strongly depend on the specific configuration of hydrides and matrix material in the fracture area. KW - Cladding KW - Radial hydrides KW - Ring compression test KW - Cohesive zone model PY - 2024 DO - https://doi.org/10.1515/kern-2024-0109 SN - 2195-8580 SP - 1 EP - 9 PB - Walter de Gruyter GmbH AN - OPUS4-62409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stamm, Michael T1 - AI-Assisted thermographic and visual classification of leading-edge erosion of wind turbine blades N2 - The wind industry is crucial for carbon neutrality, with turbines featuring blades over 100 meters long. Regular inspections, often manual and visual, struggle to capture subsurface damage or airflow dynamics. Leading-edge erosion, caused by rain and hail, significantly reduces turbine efficiency. The Federal Institute for Materials Research and Testing (BAM) in Berlin is working with industry partners to classify leading-edge damage and estimate yield loss using ground-based thermographic images. These images visualize airflow disruptions caused by erosion. AI models, trained on 1500 thermographic images, can detect and classify this damage. BAM aims to create a reference dataset by 2024, using data from 30 wind turbines. This dataset will include simultaneous thermographic and high-resolution visual images. The project also explores predicting stall and calculating performance loss due to erosion. A secure data platform facilitates data exchange and federated learning, enhancing AI systems with diverse data. KW - NDT KW - Thermography KW - Wind Turbine Blades KW - AI KW - KI-VISIR PY - 2024 UR - https://source.asnt.org/226h005/ SN - 0025-5327 VL - 82 IS - 6 SP - 14 EP - 15 AN - OPUS4-62452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Costard, Rene A1 - Duvinage, Christoph T1 - Aerosolemissionen ausgewählter Pyrotechnik N2 - Eine Betrachtung zur Gefährdungseinschätzung bestimmter pyrotechnischer Produkte bei falscher Anwendung bzw. deren missbräuchliche Verwendung. Neben Gefährdungen wie Rauch- und Gasbelastung oder Verbrennungen stehen insbesondere die Belastungen durch Aerosole im Fokus, wie diese häufig beim missbräuchlichen Abrennen in Fußballstadien eine ernsthafte Gefahr für die Zuschauer darstellen können. KW - Pyrotechnik KW - Stadien KW - Aerosole PY - 2024 VL - 2024 IS - 3 SP - 12 EP - 16 AN - OPUS4-62338 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strobl, Dominic A1 - Unger, Jörg F. A1 - Ghnatios, C. A1 - Robens-Radermacher, Annika T1 - PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency N2 - Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting their applications, for example for model parameter estimation or online process control. Model order reduction, a solution to preserve the accuracy while reducing the computation time, is explored. This article addresses challenges in developing reduced order models using the proper generalized decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model’s performance and emphasize the importance of their consideration when implementing such models. For thermal example, it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model. KW - Additive manufacturing KW - Mapping for unseparable load KW - Model order reduction (MOR) KW - Thermal transient problem KW - Sensitivity analysis KW - Proper generalized decomposition (PGD) PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598001 DO - https://doi.org/10.1002/eng2.12887 VL - 6 IS - 11 SP - 1 EP - 22 PB - John Wiley & Sons Ltd. CY - Berlin AN - OPUS4-59800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agrawal, A. A1 - Tamsen, E. A1 - Unger, Jörg F. A1 - Koutsourelakis, P-S T1 - From concrete mixture to structural design—a holistic optimization procedure in the presence of uncertainties N2 - We propose a systematic design approach for the precast concrete industry to promote sustainable construction practices. By employing a holistic optimization procedure, we combine the concrete mixture design and structural simulations in a joint, forward workflow that we ultimately seek to invert. In this manner, new mixtures beyond standard ranges can be considered. Any design effort should account for the presence of uncertainties which can be aleatoric or epistemic as when data are used to calibrate physical models or identify models that fill missing links in the workflow. Inverting the causal relations established poses several challenges especially when these involve physicsbased models which more often than not, do not provide derivatives/sensitivities or when design constraints are present. To this end, we advocate Variational Optimization, with proposed extensions and appropriately chosen heuristics to overcome the aforementioned challenges. The proposed approach to treat the design process as a workflow, learn the missing links from data/models, and finally perform global optimization using the workflow is transferable to several other materials, structural, and mechanical problems. In the present work, the efficacy of the method is exemplarily illustrated using the design of a precast concrete beam with the objective to minimize the global warming potential while satisfying a number of constraints associated with its load-bearing capacity after 28 days according to the Eurocode, the demolding time as computed by a complex nonlinear finite element model, and the maximum temperature during the hydration. KW - Black-box optimization under uncertainty KW - Mix design KW - Performance oriented design KW - Precast concrete KW - Probabilistic machine learning KW - Sustainable material design PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615443 DO - https://doi.org/10.1017/dce.2024.18 VL - 5 IS - e20 SP - 1 EP - 32 PB - Cambridge University Press CY - England AN - OPUS4-61544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Miriam E. A1 - Hilbig, Harald A1 - Stelzner, Ludwig A1 - Machner, Alisa T1 - Effect of the chemical composition of synthetic alkali-silica gels on their structure, swelling behavior and water uptake N2 - For alkali-silica reaction (ASR) gels, the relationship between swelling expansion, structure and chemical composition, particularly the effect of aluminum, remains unknown. This study investigates the structure, swelling expansion and associated water uptake of synthetic ASR gels with various Al/Si (0–0.1) and Ca/Si (0.1–0.4) ratios. The results show that aluminum incorporated into the gel structure reduces the overall swelling expansion and the leaching of silicate species during the swelling test. Moreover, they revealed that water in the Al-ASR gels is more tightly bound, reducing the overall water uptake compared to the Al-free ASR gels. Additionally, there is a linear correlation between the maximal swelling results and the ASR gel composition. However, no direct correlation emerged between the amount of water uptake and the free swelling of the ASR gels, which indicates that other factors, like the type of water bonding and pore size of the gels, are decisive for the swelling mechanism. KW - Concrete KW - Alkali-silica reaction (ASR) KW - Durability KW - 1H NMR relaxometry KW - 29Si NMR KW - 27Al NMR KW - FTIR KW - Al-ASR gel KW - Swelling test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624268 DO - https://doi.org/10.1016/j.cemconres.2024.107596 VL - 184 SP - 1 EP - 18 PB - Elsevier B.V. AN - OPUS4-62426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andrés Arcones, Daniel A1 - Weise, M. A1 - Koutsourelakis, P-S. A1 - Unger, Jörg F. T1 - Bias Identification Approaches for Model Updating of Simulation-based Digital Twins of Bridges N2 - Simulation-based digital twins of bridges have the potential not only to serve as monitoring devices of the current state of the structure but also to generate new knowledge through physical predictions that allow for better-informed decision-making. For an accurate representation of the bridge, the underlying models must be tuned to reproduce the real system. Nevertheless, the necessary assumptions and simplifications in these models irremediably introduce discrepancies between measurements and model response. We will show that quantifying the extent of the uncertainties introduced through the models that lead to such discrepancies provides a better understanding of the real system, enhances the model updating process, and creates more robust and trustworthy digital twins. The inclusion of an explicit bias term will be applied to a representative demonstrator case based on the thermal response of the Nibelungenbrücke of Worms. The findings from this work are englobed in the initiative SPP 100+, whose main aim is the extension of the service life of structures, especially through the implementation of digital twins. T2 - EWSHM 2024 11th European Workshop on Structural Health Monitoring CY - Potsdam, Germany DA - 10.06.2024 KW - Digital Twins KW - Model Bias KW - SPP100+ KW - Bridge Monitoring PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622522 DO - https://doi.org/10.58286/30524 SN - 2941-4989 IS - 12 SP - 1 EP - 10 PB - NDT.net GmbH & Co. KG CY - Mayen, Germany AN - OPUS4-62252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klewe, Tim A1 - Strangfeld, Christoph A1 - Ritzer, Tobias A1 - Kruschwitz, Sabine T1 - Classification of Practical Floor Moisture Damage Using GPR - Limits and Opportunities N2 - Machine learning in non-destructive testing (NDT) offers significant potential for efficient daily data analysis and uncovering previously unknown relationships in persistent problems. However, its successful application heavily depends on the availability of a diverse and well-labeled training dataset, which is often lacking, raising questions about the transferability of trained algorithms to new datasets. To examine this issue closely, the authors applied classifiers trained with laboratory Ground Penetrating Radar (GPR) data to categorize on-site moisture damage in layered building floors. The investigations were conducted at five different locations in Germany. For reference, cores were taken at each measurement point and labeled as (i) dry, (ii) with insulation damage, or (iii) with screed damage. Compared to the accuracies of 84 % to 90 % within the laboratory training data (504 B-Scans), the classifiers achieved a lower overall accuracy of 53 % for on-site data (72 B-Scans). This discrepancy is mainly attributable to a significantly higher dynamic of all signal features extracted from on-site measurements compared to laboratory training data. Nevertheless, this study highlights the promising sensitivity of GPR for identifying individual damage cases. In particular the results showing insulation damage, which cannot be detected by any other non-destructive method, revealed characteristic patterns. The accurate interpretation of such results still depends on trained personnel, whereby fully automated approaches would require a larger and diverse on-site data set. Until then, the findings of this work contribute to a more reliable analysis of moisture damage in building floors using GPR and offer practical insights into applying machine learning to non-destructive testing for civil engineering (NDT-CE). KW - GPR KW - Material moisture KW - Building floor KW - Machine Learning PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607932 DO - https://doi.org/10.1007/s10921-024-01111-7 SN - 0195-9298 VL - 43 IS - 3 SP - 1 EP - 16 PB - Springer Science and Business Media LLC AN - OPUS4-60793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph A1 - Grotelüschen, Bjarne A1 - Bühling, Benjamin T1 - Air-Coupled Broadband Impact-Echo Actuation Using Supersonic Jet Flow N2 - The impact-echo method (IE) is a non-destructive testing method commonly used in civil engineering. We propose a completely new approach for air-coupled actuation based on supersonic jet flow. The impinging jet sound generates continuously high sound pressures with a broad frequency bandwidth. This novel concept of utilising aeroacoustic sound for air-coupled IE was evaluated on two concrete specimens and validated using a classical IE device with physical contact. The results show a high agreement with the expected frequencies. Delaminations are correctly detected in depth and size. This proves the high reliability of air-coupled IE based on supersonic jet flow. KW - Air-coupled impact-echo KW - Impact-echo actuation KW - Building materials KW - Delamination KW - Aeroacoustic actuation · KW - Impinging jet PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600093 DO - https://doi.org/10.1007/s10921-023-01043-8 SN - 0195-9298 VL - 43 IS - 2 SP - 1 EP - 20 PB - Springer Science and Business Media LLC CY - Berlin AN - OPUS4-60009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartels, Jan-Hauke A1 - Xu, Ronghua A1 - Kang, Chongjie A1 - Herrmann, Ralf A1 - Marx, Steffen T1 - Experimental Investigation on the Transfer Behavior and Environmental Influences of Low-Noise Integrated Electronic Piezoelectric Acceleration Sensors N2 - Acceleration sensors are vital for assessing engineering structures by measuring properties like natural frequencies. In practice, engineering structures often have low natural frequencies and face harsh environmental conditions. Understanding sensor behavior on such structures is crucial for reliable masurements. The research focus is on understanding the behavior of acceleration sensors in harsh environmental conditions within the low-frequency acceleration range. The main question is how to distinguish sensor behavior from structural influences to minimize errors in assessing engineering structure conditions. To investigate this, the sensors are tested using a long-stroke calibration unit under varying temperature and humidity conditions. Additionally, a mini-monitoring system configured with four IEPE sensors is applied to a small-scale support structure within a climate chamber. For the evaluation, a signal-energy approach is employed to distinguish sensor behavior from structural behavior. The findings show that IEPE sensors display temperature-dependent nonlinear transmission behavior within the low-frequency acceleration range, with humidity having negligible impact. To ensure accurate engineering structure assessment, it is crucial to separate sensor behavior from structural influences using signal energy in the time domain. This study underscores the need to compensate for systematic effects, preventing the underestimation of vibration energy at low temperatures and overestimation at higher temperatures when using IEPE sensors for engineering structure monitoring. KW - Acceleration sensors KW - Environmental influence KW - IEPE KW - Structural Health Monitoring KW - Low-frequency shaker PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594623 UR - https://www.mdpi.com/2673-8244/4/1/4/ DO - https://doi.org/10.3390/metrology4010004 SN - 2673-8244 VL - 4 IS - 1 SP - 46 EP - 65 PB - MDPI CY - Basel AN - OPUS4-59462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimek, André A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Zehfuß, Jochen T1 - Influence of thermal strain on concrete spalling N2 - Understanding the susceptibility to spalling of concrete members in case of fire is important to evaluate the residual load-bearing capacity. The investigations of the spalling phenomenon of a concrete mixture using real scale members are necessary but expensive to carry out. Reducing the specimen size leads to an increase of boundary effects that can result in a reduced spalling or absence of spalling. In this study, fire tests were carried out on unrestrained, single-sided exposed, cuboid shaped specimens (0.6 m x 0.6 m x 0.29 m) as well as unrestrained and steel ring restrained cylindrical specimens (Ø = 0.47 m, h = 0.29 m), which induce different boundary conditions. These fire tests were carried out on two ordinary concrete mixtures. The two mixtures differ only in the type of aggregates (quartz gravel and basalt grit) and were used to investigate the influence of the thermal expansion of the aggregate on the spalling behaviour of the concrete. The results show a significant increase of the spalling depth due to the restrained thermal expansion achieved by the applied steel rings. Additionally, the type of aggregate has a direct influence on the spalling behaviour of a concrete mixture. The reduction of the boundary effects by the steel rings recreate the test conditions in the centre of a large concrete member. Thus, this type of specimen is suitable to determine the susceptibility to spalling of a material (screening-tests) as preliminary investigations to full scale fire tests. KW - Spalling KW - Concrete KW - Fire test KW - Restraint KW - Screening test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593350 DO - https://doi.org/10.1617/s11527-023-02274-x VL - 57 SP - 1 EP - 14 PB - Springer AN - OPUS4-59335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Glienke, R. A1 - Kalkowsky, F. A1 - Hobbacher, A. F. A1 - Holch, A. A1 - Thiele, Marc A1 - Marten, F. A1 - Kersten, R. A1 - Henkel, K.-M. T1 - Evaluation of the fatigue resistance of butt‑welded joints in towers of wind turbines - A comparison of experimental studies with small scale and component tests as well as numerical based approaches with local concepts N2 - Wind turbines are exposed to a high number of load cycles during their service lifetime. Therefore, the fatigue strength verification plays an important role in their design. In general, the nominal stress method is used for the fatigue verification of the most common used butt-welded joints. The Eurocode 3 part 1–9 is the current design standard for this field of application. This paper presents recent results of fatigue tests on small-scaled specimens and large components with transverse butt welds to discuss the validity of the FAT-class. Furthermore, results from numerical simulations for the verification with the effective notch stress and the crack propagation approach are used for comparison. Based on the consistency between the numerical results and the fatigue tests, the influence of the seam geometry on the fatigue resistance was investigated. Finally, a prediction of the fatigue strength of butt-welded joints with plate thicknesses up to 80 mm was carried out. KW - Transverse butt weld KW - Weld imperfections KW - Wind turbine tower KW - Fatigue strength KW - Local approaches KW - Large components KW - Wind energy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596648 DO - https://doi.org/10.1007/s40194-023-01630-3 SN - 1878-6669 SP - 1 EP - 26 PB - Springer CY - Berlin AN - OPUS4-59664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühling, Benjamin A1 - Maack, Stefan A1 - Strangfeld, Christoph T1 - Fluidic Ultrasound Generation for Non‐Destructive Testing N2 - AbstractAir‐coupled ultrasonic testing (ACU) is a pioneering technique in non‐destructive testing (NDT). While contact testing and fluid immersion testing are standard methods in many applications, the adoption of ACU is progressing slowly, especially in the low ultrasonic frequency range. A main reason for this development is the difficulty of generating high amplitude ultrasonic bursts with equipment that is robust enough to be applied outside a laboratory environment. This paper presents the fluidic ultrasonic transducer as a solution to this challenge. This novel aeroacoustic source uses the flow instability of a sonic jet in a bistable fluidic switch to generate ultrasonic bursts up to 60 kHz with a mean peak pressure of 320 Pa. The robust design allows operation in adverse environments, independent of the operating fluid. Non‐contact through‐transmission experiments are conducted on four materials and compared with the results of conventional transducers. For the first time, it is shown that the novel fluidic ultrasonic transducer provides a suitable acoustic signal for NDT tasks and has potential of furthering the implementation of ACU in industrial applications.This article is protected by copyright. All rights reserved KW - Aeroacoustics KW - Air-coupled ultrasound KW - Fluidics KW - Harsh environment KW - Laser Doppler vibrometer KW - Non-destructive testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594273 DO - https://doi.org/10.1002/adma.202311724 SN - 0935-9648 SP - 1 EP - 14 PB - Wiley AN - OPUS4-59427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wedel, F. A1 - Pitters, S. A1 - Herrmann, Ralf A1 - Schneider, Ronald A1 - Hille, Falk A1 - Hindersmann, I. T1 - Guideline for the strategic application of monitoring of road bridges in Germany N2 - Engineering structures are an important part of our transport infrastructure. Their failure is associated with high safety risks and economic damage. Ensuring the availability of these constructions and guaranteeing their operational safety are thus important tasks. Currently, maintenance of engineering structures is a reactive process and therefore not yet a predictive process. Every 3 to 6 years, the structures are visually inspected, all damages are documented and a condition grade is assigned to the structure based on the detected damages. Continuous data-providing methods such as monitoring are used only very occasionally. With the help of monitoring, condition data about the structures are continuously collected, which can be used for a better assessment of the structures. On the one hand, this would increase safety of engineering structures, and on the other hand, it makes the shift towards predictive maintenance management based on real-time data and predictions, where the onset of damage is detected before it occurs, possible in the first place. Monitoring plays therefore an important role in the management of the infrastructure. It is a crucial a step towards the digitalisation of our infrastructure and existing processes. Although there are many use cases for monitoring that have already been successfully implemented, monitoring is not yet widely used by German road authorities due to several challenges that were also identified within the scope of the project. Therefore, a guide has been developed in which the current obstacles related to monitoring are identified and possibilities for integrating monitoring into existing processes are offered. To ensure optimal alignment with the needs of road authorities, both an online survey and a workshop have been conducted. The results are summarised in a brochure that is made available to authorities to improve the use of monitoring in Germany. This paper presents the guideline and the brochure. T2 - 10th European Workshop on Structural Health Monitoring (EWSHM 2024) CY - Potsdam, Germany DA - 10.06.2024 KW - Verkehrsinfrastrukturen KW - Engineering Structures KW - Bridges KW - Structural Health Monitoring KW - Guideline PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612821 UR - https://www.ndt.net/search/docs.php3?id=29582 DO - https://doi.org/10.58286/29582 SN - 1435-4934 VL - 29 IS - 7 SP - 1 EP - 8 PB - NDT.net GmbH & Co. KG CY - Mayen AN - OPUS4-61282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosenbusch, Sjard Mathis A1 - Balzani, D. A1 - Unger, Jörg F. T1 - Regularization of softening plasticity models for explicit dynamics using a gradient-enhanced modified Johnson–Holmquist model N2 - The behavior of concrete under high strain rates is often described by plasticity models with softening, which is modeled by a reduction of the yield surface as a function of the local equivalent plastic strain. Many of these models are local and therefore produce mesh-dependent results. In this contribution, the gradient-enhancement of such models is investigated to mitigate the mesh-dependency. First, the mesh-dependency of these local formulations based on the analysis with a modified JH2 model as a representative for these constitutive formulations is demonstrated using a one-dimensional benchmark example. In the benchmark, the width of the damaged zone decreases upon mesh-refinement and the dissipated plastic energy tends to zero. It is further shown that a significantly small safety factor for the critical time step is needed in order to achieve accurate results for the benchmark example. The first investigated gradient-enhancement approach replaces the equivalent local plastic strain with its nonlocal counterpart. The enhancement is based on the inclusion of inertia and damping to the additional Helmholtz equation which enables the use of the central difference method as an explicit solver. This method successfully distributes the damage over several elements, however, the local equivalent plastic strain still localizes into one cell. The inclusion of hardening with respect to the local equivalent plastic strain inhibits the localization and the dissipated plastic energy converges with mesh-refinement. This is further confirmed in a two-dimensional wedge-splitting experiment and a four-point bending test where the damage pattern produced by the local model is mesh-dependent as well and the dissipated plastic energy tends to zero with mesh-refinement. The proposed nonlocal model with hardening results in a consistent damage pattern and the dissipated plastic energy converges. Furthermore, the nonlocal model with hardening is less sensitive to time step refinement, such that computational efficiency can be improved compared to the local model. The numerical experiments are implemented using the free open source tool FEniCSx and have been made available on Zenodo. KW - Gradient plasticity KW - Explicit dynamics KW - JH2 model KW - Concrete modeling KW - FEniCS KW - Mesh convergence KW - Time step convergence PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630453 DO - https://doi.org/10.1016/j.ijimpeng.2024.105209 SN - 1879-3509 VL - 198 SP - 1 EP - 18 PB - Elsevier Ltd. CY - Schweiz AN - OPUS4-63045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reyher, Boris A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Hückler, Alex A1 - Pistol, Klaus A1 - Madlener, Simon A1 - Schlaich, Mike T1 - Ein Supermarkt aus Infraleichtbeton: Nachweisführung bei einer Außenwand mit Brandwandanforderungen T1 - A supermarket made of infra-lightweight concrete- Proof of stability for a fire wall N2 - Infraleichtbeton (ILC) ist eine spezielle Form von Leichtbeton, der durch seine niedrige Rohdichte im Vergleich zu herkömmlichem Beton eine verbesserte Wärmedämmeigenschaft aufweist. Infraleichtbeton ermöglicht die monolithische einschichtige Konstruktion von Bauteilen der Gebäudehülle ohne additive Wärmedämmung und Fassadenbekleidung. Dadurch wird die Baukonstruktion gegenüber herkömmlich gedämmten Betonbauteilen erheblich vereinfacht und die Recyclingfähigkeit deutlich verbessert. Zudem weisen Bauteile aus Infraleichtbeton eine günstigere CO2‐Bilanz auf als Außenwandkonstruktionen in konventioneller Bauweise wie z. B. Wärmedämmverbundsysteme. Nach etwa 15 Jahren Forschung und diversen Bauvorhaben im Wohn‐ und Bildungssektor konnte nun ein erster Einzelhandelsmarkt mit Außenwänden aus Infraleichtbeton realisiert werden. Im Rahmen dieses Bauvorhabens wurde erfolgreich eine vorhabenbezogene Bauartgenehmigung (vBG) auf der Grundlage eines Brandversuchs und eines auf Berechnungen basierenden Übertragungskonzepts für eine Brandwand aus ILC erwirkt. Der Beitrag stellt das Übertragungskonzept sowie ein für die vorliegende besondere Bauweise der Brandwand entwickeltes vereinfachtes Berechnungsverfahren zum Nachweis der Standsicherheit im Brandfall vor. N2 - htweight concrete (ILC) is a special form of light-weight concrete which, due to its low density, possesses improved thermal insulation properties in comparison to normal concrete. ILC facilitates the construction of monolithic, single-layer building skins without any added thermal insulation or facade cladding. This way, the building components are effectively simplified in comparison to conventionally insulated concrete members and the recyclability is significantly improved. In addition to that, structural elements made of ILC have a reduced CO2 footprint in comparison to conventional composite elements of the building envelope. After 15 years of research and several completed construction projects in the housing and education sector, a commercial retail building has been realized. For this project, an individual approval for a firewall built out of ILC was obtained based on a fire test in combination with a transfer concept based on calculations. This article demonstrates the transfer concept as well as a simplified structural analysis concept for the proof of stability developed for the special application of a firewall. KW - Infraleichtbeton KW - Brandschutz KW - Brandwand KW - Hallenkonstruktion KW - Bauen im Bestand PY - 2024 DO - https://doi.org/10.1002/best.202400016 SN - 0005-9900 VL - 119 IS - 9 SP - 658 EP - 666 PB - Wiley AN - OPUS4-61409 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sittner, Jonathan A1 - Götze, Jens A1 - Müller, Axel A1 - Renno, Axel D. A1 - Ziegenrücker, René A1 - Pan, Yuanming T1 - Trace element analysis and luminescence behavior of quartz in pegmatites of the Tørdal Region, Norway N2 - This publication presents a study on the mineral chemistry and luminescence properties of quartz samples from pegmatites of the Tørdal region in Norway. A total of 12 samples were analyzed using Secondary Ion Mass Spectrometry (SIMS), Electron Paramagnetic Resonance Spectroscopy (EPR), and Cathodoluminescence (CL) to gain insights into their trace element concentration and distribution as well as their luminescence behavior. The samples are characterized by different Cl emissions at 450 nm, 500 nm 650 nm and an additional shoulder at 390 nm, which is only partially visible due to the absorption of the glass optics. Of these luminescence bands, the 500 nm band is the most dominant in most samples and it is characterized by an initial blue-green luminescence, which is not stable under electron irradiation. Moreover, it is characterized by a heterogeneous distribution within the samples. This luminescence can be mostly assigned to [AlO4/M+]0 defects, with charge compensation mostly achieved by Li+. Analyses by EPR spectroscopy prove the dominance of structurally bound Al, Li, and Ti ions in the investigated samples. Further analyses using SIMS mapping demonstrate that Na and K are mainly bound to micro fractures or inclusions, suggesting a limited role in the compensation of the luminescence centers. Additionally, the SIMS mappings show that some samples contain Al-rich clusters of 10 to 20 µm in diameter, whereas other trace elements are characterized by a homogeneous distribution. These clusters correspond to bright luminescence areas in size and shape and could potentially indicate H+ compensated [AlO4/M+]0 defects. KW - Quartz KW - Trace elements KW - SIMS KW - Cathodoluminescence KW - EPR KW - Tørdal KW - Pegmatite PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612529 DO - https://doi.org/10.1016/j.chemgeo.2024.122427 VL - 670 SP - 1 EP - 15 PB - Elsevier BV AN - OPUS4-61252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mugani, R. A1 - El Khalloufi, F. A1 - Kasada, M. A1 - Redouane, E. M. A1 - Haida, M. A1 - Aba, R. P. A1 - Essadki, Y. A1 - Zerrifi, S. E. A. A1 - Herter, Sven-Oliver A1 - Hejjaj, A. A1 - Aziz, F. A1 - Ouazzani, N. A1 - Azevedo, J. A1 - Campos, A. A1 - Putschew, A. A1 - Grossart, H.-P. A1 - Mandi, L. A1 - Vasconcelos, V. A1 - Oudra, B. T1 - Monitoring of toxic cyanobacterial blooms in Lalla Takerkoust reservoir by satellite imagery and microcystin transfer to surrounding farms N2 - Cyanobacterial harmful algal blooms (CyanoHABs) threaten public health and freshwater ecosystems worldwide. In this study, our main goal was to explore the dynamics of cyanobacterial blooms and how microcystins (MCs) move from the Lalla Takerkoust reservoir to the nearby farms. We used Landsat imagery, molecular analysis, collecting and analyzing physicochemical data, and assessing toxins using HPLC. Our investigation identified two cyanobacterial species responsible for the blooms: Microcystis sp. and Synechococcus sp. Our Microcystis strain produced three MC variants (MC-RR, MC-YR, and MC-LR), with MC-RR exhibiting the highest concentrations in dissolved and intracellular toxins. In contrast, our Synechococcus strain did not produce any detectable toxins. To validate our Normalized Difference Vegetation Index (NDVI) results, we utilized limnological data, including algal cell counts, and quantified MCs in freeze-dried Microcystis bloom samples collected from the reservoir. Our study revealed patterns and trends in cyanobacterial proliferation in the reservoir over 30 years and presented a historical map of the area of cyanobacterial infestation using the NDVI method. The study found that MC-LR accumulates near the water surface due to the buoyancy of Microcystis. The maximum concentration of MC-LR in the reservoir water was 160 μg/L. In contrast, 4 km downstream of the reservoir, the concentration decreased by a factor of 5.39 to 29.63 μg/L, indicating a decrease in MC-LR concentration with increasing distance from the bloom source. Similarly, the MC-YR concentration decreased by a factor of 2.98 for the same distance. Interestingly, the MC distribution varied with depth, with MC-LR dominating at the water surface and MC-YR at the reservoir outlet at a water depth of 10 m. Our findings highlight the impact of nutrient concentrations, environmental factors, and transfer processes on bloom dynamics and MC distribution. We emphasize the need for effective management strategies to minimize toxin transfer and ensure public health and safety. KW - Cyanotoxin KW - HPLC-MS/MS KW - Surface water PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623672 DO - https://doi.org/10.1016/j.hal.2024.102631 SN - 1568-9883 VL - 135 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam AN - OPUS4-62367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Isleyen, Alper A1 - Özcan, Kemal A1 - Tunc, Murat A1 - Boztepe, Aylin A1 - Coşkun, Fatma Gonca A1 - Moshammer, Kai A1 - Shehab, Moaaz A1 - Stratulat, Camelia A1 - Bratu, Adriana A1 - Hafner-Vuk, Katarina A1 - Vogl, Jochen A1 - Strzelec, Michał A1 - Calvo, Mariana Villegas A1 - Frey, Anne Mette A1 - Strauss, Helena T1 - Development of three biofuel CRMs for the quality parameters in biodiesel and wood pellet via a joint research project N2 - Biomass is a key element in biofuels which can be defined as a fuel produced through contemporary biological processes, and its increased use can support the EU’s aims of reducing greenhouse gas emissions. Information on the nature and the quality of the biomass or biofuel is important in order to support the optimization of their combustion with respect to realizing higher efficiencies and lower emissions during energy production. Three reference materials were produced by a collaborative approach among national metrology institutes and designated institutes within the scope of the EMPIR project: BIOFMET. The project was aimed to establish advanced traceable measurement standards for the determination of the calorific value, impurities, and other parameters such as density, kinematic viscosity, moisture, and ash. This paper presents the sampling and processing methodology, homogeneity, stability, characterization campaign, the assignment of property values, and their associated uncertainties in compliance with ISO 17034 for biofuel reference materials: biodiesel, wood pellet powder, and wood pellet. Parameters of interest in biodiesel reference material-UME BIOFMET CRM 01 are gross calorific value (GCV), density, viscosity, and mass fractions of Ca, K, Mg, Na, P, and S elements. Parameters to be certified in wood pellet powder reference material-UME BIOFMET CRM 02 are GCV, moisture, ash, and mass fractions of Al, Cr, K, Mg, Mn, Ni, S, and Zn elements. Parameters to be certified in the wood pellet reference material-UME BIOFMET CRM 03 are GCV and moisture. The homogeneity and stability of the materials were assessed in accordance with ISO 33405. The materials were characterized by interlaboratory comparison studies among competent metrology institute and designated institute laboratories. Assigned values and uncertainties of the certified values were calculated in accordance with ISO 33405, and uncertainties include characterization, homogeneity, and stability components. The developed CRMs are intended to be used for the development and validation of measurement procedures for the determination and quality control/assurance purposes of the quality parameters for biofuels. It should be emphasized that the UME BIOFMET CRM 01-Biodiesel CRM is the first biodiesel reference material certified for calorific value. Among the developed wood CRMs, the pellet form, UME BIOFMET CRM 03, was found to be more stable than the powder one, UME BIOFMET CRM 02, for the moisture parameter. Sixfold lower relative uncertainty value for short-term stability at 45 °C and twofold lower relative uncertainty value for long-term stability at 22 °C were obtained for the moisture parameter of the CRM in pellet form compared to the CRM in powder form. KW - Biofuel KW - Biodiesel KW - Wood pellet KW - Calorific value KW - Moisture KW - Element content PY - 2024 DO - https://doi.org/10.1007/s00216-024-05694-y SP - 1 EP - 13 PB - Springer Science and Business Media LLC AN - OPUS4-62371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartels, Jan-Hauke A1 - Gündogdu, Berk A1 - Herrmann, Ralf A1 - Marx, Steffen T1 - Beschleunigungssensoren zur Zustandsüberwachung von Ingenieurbauwerken unter Einfluss von Umweltfaktoren bei tiefen Frequenzen T1 - Acceleration sensors for structural health monitoring of engineering structures under the influence of environmental factors at low frequencies N2 - Structural Health Monitoring (SHM) wird zunehmend zur kontinuierlichen Zustandsbewertung von Ingenieurbauwerken eingesetzt. Wichtige Bewertungsparameter sind globale Systemeigenschaften, wie z. B. Eigenfrequenzen, zu deren Bestimmung Beschleunigungssensoren eingesetzt werden. Häufig werden sog. MEMS-Sensoren (Micro Electro Mechanical Systems) verwendet, die jedoch ein hohes Rauschniveau aufweisen. Alternativ können rauschärmere IEPE-Sensoren (Integrated Electronics Piezo Electric) eingesetzt werden, die auch bei geringster Strukturanregung Schwingungen zuverlässig erfassen. Ferner besteht das Problem, dass Änderungen der Eigenfrequenzen infolge Bauwerksschädigung schwer von Änderungen der Eigenfrequenzen infolge Umwelteinflüssen zu unterscheiden sind. Letztere verändern die Eigenschaften der Struktur und die des Messsystems. Um Umwelteinflüsse auf das Messsystem im Anwendungsgebiet Ingenieurbau zu untersuchen, wurden IEPE-Beschleunigungsaufnehmer hinsichtlich ihres Übertragungsverhaltens im niederfrequenten Beschleunigungsbereich analysiert. Es zeigt sich, dass das Verhalten nicht nur frequenz-, sondern auch temperaturabhängig ist, während die Luftfeuchte keinen Einfluss hat. Diese für das Bauwerk unbedenklichen Einflüsse müssen für eine robuste Zustandsüberwachung kompensiert werden. Für die Anwendung im Ingenieurbau werden IEPE-Sensoren empfohlen, da sie ein hohes Signal-zu-Rausch-Verhältnis aufweisen und niederfrequente Bauwerksschwingungen zuverlässig erfassen. N2 - Acceleration sensors for structural health monitoring of engineering structures under the influence of environmental factors at low frequencies. Structural health monitoring (SHM) is increasingly used to continuously assess the condition of engineering structures. Important assessment parameters are global system properties, such as eigenfrequency, which are measured by accelerometers. Micro-electro-mechanical systems (MEMS) sensors are often used, but have a high noise level. Alternatively, low-noise IEPE (integrated electronics piezo electric) sensors can be used, which reliably detect vibrations even with the slightest structural excitation. Another problem is that changes in eigenfrequency due to structural damage are difficult to distinguish from changes in eigenfrequency due to environmental effects. The latter change the properties of both the structure and the measurement system. In order to investigate environmental effects on the measurement system in the field of civil engineering, IEPE accelerometers have been analyzed for their transmission behavior in the low-frequency acceleration range. It was found that the behavior is not only frequency dependent, but also temperature dependent, while humidity has no influence. These nonstructural effects must be compensated for to ensure robust condition monitoring. IEPE sensors are recommended for civil engineering applications because of their high signal-to-noise ratio and ability to reliably detect low-frequency structural vibrations. KW - Beschleunigungssensoren KW - Kalibrierung KW - Structural Health Monitoring KW - Umwelteinflüsse KW - Übertragungsverhalten KW - acceleration sensors KW - calibration KW - environmental influences KW - transmission behavior PY - 2024 DO - https://doi.org/10.1002/bate.202300056 SN - 1437-0999 SN - 0932-8351 VL - 101 IS - 10 SP - 1 EP - 11 PB - Ernst & Sohn CY - Berlin AN - OPUS4-60772 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schepers, Winfried A1 - Brinkgreve, Ronald B. J. A1 - Holtzendorff, Kira A1 - Wegener, Dirk A1 - Appel, Silke A1 - Efthymiou, Georgia A1 - Krajewski, Wolfgang A1 - Machaček, Jan A1 - Meier, Thomas A1 - Nseir, Bashar A1 - Rangelow, Peter A1 - Schmitt, Jürgen A1 - Staubach, Patrick A1 - Vrettos, Christos T1 - Numerische Ermittlung von Baugrundschwingungen bei dynamisch belasteten Fundamenten: Empfehlungen zur Modellierung T1 - Numerical analysis of soil vibrations due to vibrating foundations: Guidance for model design N2 - AbstractIn der Praxis tätige geotechnisch Planende kommen in zunehmendem Maße mit dynamischen Fragestellungen in Berührung. Hersteller von geotechnischer Berechnungssoftware haben entsprechend ihre ursprünglich für statische Aufgabenstellungen konzipierten Produkte um die Möglichkeit zur Lösung von Wellenausbreitungsproblemen im Baugrund erweitert. Den Anwendern fehlt aber häufig die notwendige Erfahrung zur Durchführung dieser Art von numerischen Berechnungen. Die Arbeitskreise 1.4 „Baugrunddynamik“ und 1.6 „Numerik in der Geotechnik“ der Deutschen Gesellschaft für Geotechnik (DGGT) haben diese Entwicklung aufgegriffen und einen gemeinsamen Unterarbeitskreis „Numerik in der Baugrunddynamik“ gegründet. Der vorliegende Beitrag stellt die aktuellen Ergebnisse der Arbeit des Unterarbeitskreises vor und fasst die gewonnenen Erkenntnisse in Form von Empfehlungen zusammen. N2 - Geotechnical engineers are increasingly concerned with wave propagation problems. Manufacturers of geotechnical analysis software added features for soil dynamic analyses to their products initially devised for static geotechnical analyses. Though, users often lack the experience for conducting such advanced numerical analyses. Working groups 1.4 "Soil dynamics" and 1.6 "Numerical analyses in geotechnical engineering" of DGGT German Society for Geotechnical Engineering established a joint subgroup "Numerical analyses in soil dynamics" to address this shortcoming. The present paper presents the work of the subgroup so far and provides some guidance on conducting numerical analyses in soil dynamics. KW - Wellenausbreitung KW - Numerische Methoden KW - Empfehlungen KW - Modellgröße KW - Zeitschrittweite PY - 2024 DO - https://doi.org/10.1002/gete.202400016 SN - 0172-6145 VL - 47 IS - 4 SP - 254 EP - 268 PB - Ernst CY - Berlin AN - OPUS4-62078 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Hille, Falk A1 - Herrmann, Ralf A1 - Baeßler, Matthias T1 - Vibration-based system identification of a large steel box girder bridge N2 - The Bundesanstalt für Materialforschung und -prüfung (BAM) collaborates with TNO to develop a software framework for automated calibration of structural models based on monitoring data. The ultimate goal is to include such models in the asset management process of engineering structures. As a basis for developing the framework, a multi-span road bridge consisting of ten simply supported steel box girders was selected as a test case. Our group measured output-only vibration data from one box girder under ambient conditions. From the data, we determined eigenfrequencies and mode shapes. In parallel, we developed a preliminary structural model of the box girder for the purpose of predicting its modal properties. In this contribution, we provide an overview of the measurement campaign, the operational modal analysis, the structural modeling and qualitatively compare the identified with the predicted modes. As an outlook, we discuss the further steps in the calibration process and future applications of the calibrated model. T2 - XII International Conference on Structural Dynamics (EURODYN 2023) CY - Delft, The Netherlands DA - 02.07.2023 KW - Verkehrsinfrastukturen KW - SHM KW - Model updating KW - System identification KW - Operational modal analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605041 DO - https://doi.org/10.1088/1742-6596/2647/18/182039 SN - 1742-6596 VL - 2647 IS - 18 SP - 1 EP - 9 PB - IOP Publishing CY - Bristol AN - OPUS4-60504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - 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 - Pech May, Nelson Wilbur A1 - Lecompagnon, Julien A1 - Hirsch, Philipp Daniel A1 - Ziegler, Mathias T1 - Robot-assisted crack detection on complex shaped components using constant-speed scanning infrared thermography with laser line excitation N2 - Infrared thermography (IRT) using a focused laser is effective for surface defect detection. Nevertheless, testing complex‐shaped components remains a challenging task. The state‐of‐the‐art focuses on testing a limited region of interest rather than the full sample. Thus, detection and location of surface defects has been less researched. Most attempts require a manual scan of the full sample, which makes it hard to reconstruct the full scanned surface. Here, we introduce a reliable workflow for crack detection and semi‐automated inspection of complex‐shaped components using IRT excited with a laser line. A 6‐axis robot arm is used for moving the sample in front of the setup. This approach has been tested on a section of a rail and a gear, both containing defects due to heavy use. Crack detection is based on the segmentation of thermograms obtained by Fourier transform of sorted temperatures. Moreover, texture mapping is used to visualize a reconstructed thermogram on the 3D model of the sample. Our approach illustrates a reliable process towards the digitalization of thermographic testing. KW - Crack detection KW - Infrared thermography KW - Laser line excitation KW - Robot‐assisted KW - Texture mapping PY - 2024 DO - https://doi.org/10.1002/appl.202400007 SN - 2702-4288 VL - 4 IS - 1 SP - 1 EP - 13 PB - John Wiley & Sons, Ltd AN - OPUS4-60910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Patrick A1 - Schneider, Ronald A1 - Baeßler, Matthias A1 - Morgenthal, Guido ED - Cha, Young-Jin T1 - A Bayesian Probabilistic Framework for Building Models for Structural Health Monitoring of Structures Subject to Environmental Variability N2 - Managing aging engineering structures requires damage identification, capacity reassessment, and prediction of remaining service life. Data from structural health monitoring (SHM) systems can be utilized to detect and characterize potential damage. However, environmental and operational variations impair the identification of damages from SHM data. Motivated by this, we introduce a Bayesian probabilistic framework for building models and identifying damage in monitored structures subject to environmental variability. The novelty of our work lies (a) in explicitly considering the effect of environmental influences and potential structural damages in the modeling to enable more accurate damage identification and (b) in proposing a methodological workflow for model‐based structural health monitoring that leverages model class selection for model building and damage identification. The framework is applied to a progressively damaged reinforced concrete beam subject to temperature variations in a climate chamber. Based on deflections and inclinations measured during diagnostic load tests of the undamaged structure, the most appropriate modeling approach for describing the temperature‐dependent behavior of the undamaged beam is identified. In the damaged state, damage is characterized based on the identified model parameters. The location and extent of the identified damage are consistent with the cracks observed in the laboratory. A numerical study with synthetic data is used to validate the parameter identification. The known true parameters lie within the 90% highest density intervals of the posterior distributions of the model parameters, suggesting that this approach is reliable for parameter identification. Our results indicate that the proposed framework can answer the question of damage identification under environmental variations. These findings show a way forward in integrating SHM data into the management of infrastructures. KW - Verkehrsinfrastukturen KW - SHM KW - Model Updating KW - Environmental and Operational Variability KW - Damage Identification KW - Model Building PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605027 DO - https://doi.org/10.1155/2024/4204316 SN - 1545-2255 VL - 2024 IS - 1 SP - 1 EP - 23 PB - Wiley AN - OPUS4-60502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herrmann, Ralf A1 - Ramasetti, Eshwar Kumar A1 - Degener, Sebastian A1 - Hille, Falk A1 - Baeßler, Matthias T1 - A living lab for Structural Health Monitoring at the Nibelungen Bridge Worms for Transfer Learning of Structural Dynamics N2 - The Nibelungen Bridge in Worms, Germany has been selected as a national demonstration structure for advanced non-destructive testing (NDT) and structural health monitoring concepts to extend the lifetime of civil structures and to optimize O&M actions. Parts of the research that involves this bridge as a demonstrator belong to the focus area program SPP100+. In this program, the bridges SHM System has been extended and combined with an additional setup of vibration sensors. The used digital smart sensor with pre-processing functions, the arrangement of the sensors at the structure and additional edge computing capability allows the investigation of transfer learning and other methods directly into the real structure. The living lab with seven triaxial accelerometers can be reconfigured in real-time and adjusted to the needs of AI models for classification. The comparison with the existing conventional SHM sensors has been made possible by hardware synchronization to the existing SHM System and collocating sensors at similar positions, so that a hardware exchange can be an investigated use-case for the transfer learning. During idle times, the system collects vibration data like a conventional SHM system. T2 - 10th European Workshop on Structural Health Monitoring (EWSHM 2024) CY - Potsdam DA - 10.06.2024 KW - Nibelungen Bridge KW - Living Lab KW - Transfer Learning KW - Transfer Structures KW - Modal Analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612810 UR - https://www.ndt.net/search/docs.php3?id=29853 DO - https://doi.org/10.58286/29853 SN - 1435-4934 VL - 29 IS - 7 SP - 1 EP - 8 PB - NDT.net GmbH & Co. KG CY - Mayen AN - OPUS4-61281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ramasetti, Eshwar Kumar A1 - Herrmann, Ralf A1 - Degener, Sebastian A1 - Baeßler, Matthias T1 - Development of generic AI models to predict the movement of vehicles on bridges N2 - For civil, mechanical, and aerospace structures to extend operation times and to remain in service, structural health monitoring (SHM) is vital. SHM is a method to examining and monitoring the dynamic behavior of essential constructions. Because of its versatility in detecting unfavorable structural changes and enhancing structural dependability and life cycle management, it has been extensively used in many engineering domains, especially in civil bridges. Due to the recent technical developments in sensors, high-speed internet, and cloud computing, data-driven approaches to structural health monitoring are gaining appeal. Since artificial intelligence (AI), especially in SHM, was introduced into civil engineering, these modern and promising methods have attracted significant research attention. In this work, a large dataset of acceleration time series using digital sensors was collected by installing a structural health monitoring (SHM) system on Nibelungen Bridge located in Worms, Germany. In this paper, a deep learning model is developed for accurate classification of different types of vehicle movement on the bridge from the data obtained from accelerometers. The neural network is trained with key features extracted from the acceleration dataset and classification accuracy of 98 % was achieved. KW - Structural Health Monitoring KW - Artifical Intelligence KW - Machine Learning KW - Nibelungen Bridge PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620289 DO - https://doi.org/10.1016/j.prostr.2024.09.307 VL - 64 SP - 557 EP - 564 PB - Elsevier B.V. AN - OPUS4-62028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pimienta, Pierre A1 - McNamee, Robert A1 - Robert, Fabienne A1 - Boström, Lars A1 - Huang, Shan-Shan A1 - Mróz, Katarzyna A1 - Davie, Colin A1 - Mohaine, Siyimane A1 - Alonso, Maria Cruz A1 - Bodnarova, Lenka A1 - Bosnjak, Josipa A1 - Dal Pont, Stefano A1 - Dao, Vinh A1 - Dauti, Dorjan A1 - Dehn, Frank A1 - Felicetti, Roberto A1 - Hager, Izabela A1 - Hela, Rudolf A1 - Hozjan, Tomaz A1 - Juknat, Michael A1 - Jumppanen, Ulla-Maija A1 - Kirnbauer, Johannes A1 - Kolsek, Jerneja A1 - Korzen, Manfred A1 - Lakhani, Hitesh A1 - Lion, Maxime A1 - Lo Monte, Francesco A1 - Maluk, Cristian A1 - Meftah, Fekri A1 - Miah, Md Jihad A1 - Millard, Alain A1 - Mindeguia, Jean-Christophe A1 - Moreau, Bérénice A1 - Msaad, Yahia A1 - Ozawa, Mitsuo A1 - Pesavento, Francesco A1 - Pham, Duc Toan A1 - Pistol, Klaus A1 - Rickard, Ieuan A1 - Rodrigues, Joao Paulo Correia A1 - Roosefid, Mohsen A1 - Schneider, Martin A1 - Sharma, Umesh Kumar A1 - Sideris, Kosmas A1 - Stelzner, Ludwig A1 - Weber, Benedikt A1 - Weise, Frank T1 - Recommendation of RILEM TC 256-SPF on fire spalling assessment during standardised fire resistance tests: complementary guidance and requirements N2 - The recommendation is based on the co-authors’ work organized by the RILEM TC 256-SPF “Spalling of concrete due to fire: testing and modelling”. It aims to provide useful information, guidance and best practices in fire spalling assessment to laboratories that perform large-scale tests based on fire resistance test standards. It provides guidance on the spalling observation techniques during testing, as well as post-test spalling quantification/assessment methods. This document is intended to be used in conjunction with the fire resistance test standards, e.g. EN 1363-1 and ISO 834-1. KW - Concrete KW - Fire spalling KW - Large scale tests KW - Standardised fire resistance tests PY - 2024 DO - https://doi.org/10.1617/s11527-023-02248-z SN - 1871-6873 VL - 57 IS - 1 SP - 1 EP - 12 PB - Springer CY - Dordrecht AN - OPUS4-59288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asna Ashari, Parsa A1 - Oh, Hyochan A1 - Koch, Claudia T1 - Pathways to the hydrogen economy: A multidimensional analysis of the technological innovation systems of Germany and South Korea N2 - The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry, politics, and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition, this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea, both recognized as global frontrunners in advancing and implementing hydrogen-based solutions. By providing a multidimensional assessment of pathways to the hydrogen economy, our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance, and (ii) we emphasize the social perspective within the hydrogen TIS. To this end, we conducted 24 semi-structured expert interviews, applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However, several barriers still hinder the further realization of a hydrogen economy. Based on our findings, we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition. KW - Hydrogen economy KW - Technological innovation system KW - Quality infrastructure KW - Multidimensional technology adoption KW - Social acceptance PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593312 DO - https://doi.org/10.1016/j.ijhydene.2023.08.286 IS - Volume 49, Part D SP - 405 EP - 421 PB - Elsevier AN - OPUS4-59331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ladu, Luana A1 - Koch, Claudia A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Technology adoption and digital maturity in the conformity assessment industry: Empirical evidence from an international study N2 - Technological innovation and digitalization are transforming industries and organizations worldwide. Digital Maturity Models often serve as a reference point to monitor the digitalization progression through prescribed stages. Yet, little is still understood about (i) how a digital maturity model should be designed and deployed in a specific industry setting and (ii) the association between digital maturity and technology adoption. Building on extant literature and extensive interviews with industry experts, we first develop a digital maturity model in the context of the conformity assessment industry (a globally regulated industry responsible for assessing compliance of organizations with standards and regulations). Second, we implement the model and conduct a survey across 1447 organizations in 15 countries. Our findings reveal that the digital transformation journey of the industry progresses along five stages of maturity (with most organizations in the early/ intermediate stages of digital maturity) with distinctive patterns of technical and managerial practices across all stages. Adoption of technologies is (unsurprisingly) associated with higher digital maturity levels - albeit that association does not hold for complex technologies (such as Blockchain) and is impacted by country specifics (measured by the Digital Skills Gap Index). Our study provides insights into digital maturity and the adoption of technologies in an institutional environment that is highly regulated and conservative, in which high integrity of service provision is primary, and digitalization is a secondary focus of organizations. KW - Digital Maturity KW - Standardisation KW - Digital Maturity Scores KW - Technology Adoption KW - Digital Technologies PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601930 DO - https://doi.org/10.1016/j.techsoc.2024.102564 SN - 0160-791X VL - 77 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-60193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Swaminathan, Srinivasan A1 - Kumar, S. A1 - Kranzmann, Axel A1 - Hesse, Rene A1 - Goldbeck, Hennig A1 - Fantin, Andrea T1 - Corrosion characteristics of 316L stainless steel in oxide-rich molten solar salt at 600◦C N2 - An attempt has been made in this work, to observe the influence on alloy aging by the sodium oxide (Na2O) in solar salt (60 wt% NaNO3 + 40 wt% KNO3). The accelerated aging was established by adding Na2O (0.005, 0.07, 0.135 and 0.2 wt%) to the solar salt and their effect on corrosion of 316L stainless steel (SS) at 600 ◦C in that oxide-rich solar salts for 168 h in synthetic air was investigated. Corrosion is significantly more in oxide-rich solar salt compared to pure solar salt. Strikingly, the oxide scale-base metal interface is wavy in solar salt containing 0.005 % Na2O clearly shows the oxide addition to salt melt influences Cr-rich inner oxide layer formation and its selective dissolution at early stage that leads to non-uniform corrosion. Interestingly, with increase of Na2O to 0.07 %, steel corrosion proceeded uniformly by accelerated disintegration of Cr-rich inner layer and subsequent dissolution. Severe scale spallation and weight loss in nitrate melt containing 0.2 % Na2O fostering more rapid corrosion, alarming that substantial tolerance of oxide content in solar salt is ≥ 0.135 % for an acceptable corrosion of 316L SS. Despite preferential dissolution of Cr and scale degradation/spallation with increased oxide content in solar salt, the corrosion layer in all cases comprised of sodium ferrite, and Cr-rich Cr-Fe mixed oxides with the Ni enrichment at the scale-metal interface. Competing processes between oxide scale growth, degradation and dissolution or even spallation has been discussed with an emphasis of Na2O addition to solar salt. KW - Molten salt corrosion KW - Solar salt KW - Thermal energy storage KW - Stainless steel KW - Concentrating solar power PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610819 DO - https://doi.org/10.1016/j.solmat.2024.113176 VL - 278 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-61081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kimiaei, E. A1 - Farooq, M. A1 - Szymoniak, Paulina A1 - Ahmadi, Shayan A1 - Babaeipour, S. A1 - Schönhals, Andreas A1 - Österberg, M. T1 - The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films N2 - Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC). QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials. Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications. KW - Lignin KW - Nanocomposites PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615098 DO - https://doi.org/10.1016/j.jcis.2024.10.083 SN - 0021-9797 VL - 679 SP - 263 EP - 275 PB - Elsevier Inc. AN - OPUS4-61509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lauhoff, Christian A1 - Degener, Sebastian A1 - Bolender, Artjom A1 - Liehr, Alexander A1 - Hübner, Leoni A1 - Frenck, Johanna-Maria A1 - Molotnikov, Andrey A1 - Niendorf, Thomas T1 - In Situ Synchrotron Diffraction Assessment of Reversibility of the Martensitic Transformation in Single-Crystalline Co–Ni–Ga Shape Memory Alloy Under Torsion N2 - AbstractHeusler-type Co–Ni–Ga shape memory alloys attracted significant attention due to their excellent functional properties in single-crystalline state under both compressive and tensile loading. The present study investigates the superelastic deformation behavior under torsion. Using a newly installed torsion testing setup, in situ synchrotron diffraction was carried out on single-crystalline material in order to investigate the martensitic phase transformation. Incremental deformation experiments reveal a fully reversible martensitic transformation under torsional loading at room temperature, leading to excellent strain recovery after deformation to 6.5% shear strain. Furthermore, relevant aspects towards the analysis of powder diffraction data obtained for single-crystalline material in transmission mode under torsional loading are presented and critically discussed. KW - Shape memory alloy KW - Pseudoelasticity KW - Martensitic transformation KW - Synchrotron diffraction KW - In situ testing KW - Torsion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621872 DO - https://doi.org/10.1007/s40830-024-00496-8 VL - 10 SP - 326 EP - 333 PB - Springer Science and Business Media LLC AN - OPUS4-62187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Runze A1 - Sur, Debashish A1 - Li, Kangming A1 - Witt, Julia A1 - Black, Robert A1 - Whittingham, Alexander A1 - Scully, John R. A1 - Hattrick-Simpers, Jason T1 - Bayesian assessment of commonly used equivalent circuit models for corrosion analysis in electrochemical impedance spectroscopy N2 - Electrochemical Impedance Spectroscopy (EIS) is a crucial technique for assessing corrosion of metallic materials. The analysis of EIS hinges on the selection of an appropriate equivalent circuit model (ECM) that accurately characterizes the system under study. In this work, we systematically examined the applicability of three commonly used ECMs across several typical material degradation scenarios. By applying Bayesian Inference to simulated corrosion EIS data, we assessed the suitability of these ECMs under different corrosion conditions and identified regions where the EIS data lacks sufficient information to statistically substantiate the ECM structure. Additionally, we posit that the traditional approach to EIS analysis, which often requires measurements to very low frequencies, might not be always necessary to correctly model the appropriate ECM. Our study assesses the impact of omitting data from low to medium-frequency ranges on inference results and reveals that a significant portion of low-frequency measurements can be excluded without substantially compromising the accuracy of extracting system parameters. Further, we propose simple checks to the posterior distributions of the ECM components and posterior predictions, which can be used to quantitatively evaluate the suitability of a particular ECM and the minimum frequency required to be measured. This framework points to a pathway for expediting EIS acquisition by intelligently reducing low-frequency data collection and permitting on-the-fly EIS measurements. KW - Electrochemical Impedance Spectroscopy (EIS) KW - MAPz@BAM KW - Bayesian Inference KW - Corrosion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623392 DO - https://doi.org/10.1038/s41529-024-00537-8 VL - 8 SP - 120 PB - Springer Materials AN - OPUS4-62339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radenberg, M. A1 - Schwettmann, K. A1 - Weigel, Sandra T1 - Möglichkeiten der vollständigen oder teilweisen Substitution von Bitumen als Bindemittel im Asphaltstraßenbau N2 - Die Klimakrise sowie die damit verbundene Distanzierung vom Erdöl und die aktuelle geopolitische Situation in Europa erfordern, dass die Asphaltbranche sowohl lang- als auch kurzfristig einen erdölunabhängigen Weg einschlägt. Langfristig sollte dabei ein vollständiger Ersatz des Bitumens durch biobasierte, nachhaltige Alternativmaterialien erfolgen, während kurz- bzw. mittelfristig ein teilweiser Ersatz bzw. eine Wiederverwendung von Asphalt mit biobasierten Alternativmaterialien eine Reduzierung der Erdölabhängigkeit erlauben würden. In diesem Zusammenhang wurden in dem Projekt „Möglichkeiten der vollständigen oder teilweisen Substitution von Bitumen als Bindemittel im Asphaltstraßenbau“ in einer umfassenden Literaturrecherche Erfolg versprechende Alternativbindemittel zur Bitumensubstitution und Bindemittelverjüngung identifiziert. Eine vielversprechende Eignung zeigen dabei vor allem verschiedene auf pflanzlicher Biomasse basierende Materialien (z. B. Lignine in Kombination mit öligen Komponenten, Bioöle, Zuckerrohrmelasse/-bagasse), aber auch Produkte basierend auf tierischer Biomasse (z. B. aufbereitete Schweinegülle), aquatischer Biomasse (z. B. Rückstände der Mikroalgenaufbereitung) oder aus Abfällen (z. B. gebrauchtes Speiseöl). N2 - The climate crisis with the increasing distancing from crude oil and the current geopolitical situation in Europe require the asphalt industry to take a path that is independent of crude oil in both the long and short term. In the long term, bitumen should be completely replaced by bio-based, sustainable alternative materials, while in the short and medium term, partial replacement, or reuse of asphalt with bio-based alternative materials for rejuvenation would reduce dependence on oil. In this context, the project “Possibilities for the total or partial substitution of bitumen as a binder in asphalt road construction” identifi ed promising alternative binders for bitumen substitution and binder rejuvenation in a comprehensive literature review. The most promising suitability is shown by various materials based on plant biomass (e. g. lignins in combination with oily components, bio-oils, sugar cane molasses/bagasse, but also products based on animal biomass (e. g. processed swine manure), aquatic biomass (e. g. residues from microalgae processing) or from waste (e. g. waste cooking oil). KW - Nachhaltiger Asphaltstraßenbau KW - Teilweise und vollständige Bitumensubstitution KW - Asphaltwiederverwendung KW - Pflanzliche Biomasse KW - Tierische Biomasse KW - Meeresbiomasse KW - Abfälle PY - 2024 DO - https://doi.org/10.53184/STA10-2024-2 IS - 11 SP - 896 EP - 901 PB - Kirschbaum Verlag AN - OPUS4-62099 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becks, H. A1 - Lippold, L. A1 - Winkler, P. A1 - Moeller, M. A1 - Rohrer, M. A1 - Leusmann, T. A1 - Anton, D. A1 - Sprenger, B. A1 - Kähler, P. A1 - Rudenko, I. A1 - Andrés Arcones, Daniel A1 - Koutsourelakis, P. A1 - Unger, Jörg F. A1 - Weiser, M. A1 - Petryna, Y. A1 - Schnellenbach-Held, M. A1 - Lowke, D. A1 - Hessels, H. A1 - Lenzen, A. A1 - Zabel, V. A1 - Könke, C. A1 - Claßen, M. A1 - Hegger, J. T1 - Neuartige Konzepte für die Zustandsüberwachung und -analyse von Brückenbauwerken – Einblicke in das Forschungsvorhaben SPP100+ N2 - Die Brückeninfrastruktur in Deutschland und Europa steht aufgrund steigender Verkehrslasten und alternder Bauwerke vor erheblichen Herausforderungen. Das DFG-Schwerpunktprogramm 2388 „Hundert plus – Verlängerung der Lebensdauer komplexer Baustrukturen durch intelligente Digitalisierung“ (SPP100+) strebt an, durch digitale Innovationen und prädiktive Instandhaltungsstrategien die Nutzungsdauer bestehender Brückenbauwerke zu verlängern. Der vorliegende Beitrag fokussiert sich auf das SPP100+ zugehörige Cluster „Monitoring und Simulation“, das sieben Teilprojekte umfasst. Die Projekte entwickeln fortschrittliche Methoden zur Überwachung und Zustandsbewertung von Brücken mittels Digitaler Zwillinge, hochauflösender Sensortechnik und numerischer Simulationen. Innovative Ansätze wie nichtlineare Modellanpassungen, stochastische Methoden und künstliche Intelligenz ermöglichen eine präzise und frühzeitige Identifizierung potenzieller Schäden. Die Kombination aus kontinuierlichem Bauwerksmonitoring und effizienter Datenauswertung ist entscheidend für die langfristige Sicherheit und Langlebigkeit bestehender Brücken und trägt darüber hinaus zur Ressourcenschonung bei. KW - Bauwerkserhaltung KW - Brückenbau KW - Monitoring KW - Lebensdauer PY - 2024 DO - https://doi.org/10.37544/0005-6650-2024-10-63 SN - 0005-6650 VL - 99 IS - 10 SP - 327 EP - 338 PB - VDI Verlag-eLibrary - technisches Wissen für Ingenieur*innen CY - Düssledorf AN - OPUS4-61563 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brockmann, N. A1 - Sicken, A. A1 - Krüger, Jörg T1 - Effects of laser cleaning on the condition of different silk model samples using varying wavelengths and pulse durations N2 - The cleaning of aged silk fibers poses a common challenge in the conservation of textiles, since traditional cleaning techniques often yield unsatisfactory results or even harm objects. In this regard, cleaning objects with laser radiation is a promising addition to the range of available methods. Due to it being contactless, even brittle and touch-sensitive objects with disfiguring or harmful soiling could potentially be cleaned and therefore made accessible for research and presentation. Examples of treatment have sometimes shown spectacular results. Still there is some skepticism concerning the safety of this treatment for textile materials, which has been strengthened through previous 532 nm wavelength nanosecond laser cleaning studies on silk fibers. Taking these published results into account, the range of examined laser parameters has been extended in this study, from 532 nm nanosecond laser to 1064 nm nanosecond and even 800 nm femtosecond laser, reevaluating the effect of this treatment on the fibers. The physicochemical processes taking place on the silk fibers when cleaning with lasers are complex and still not fully understood. The aim of this project was therefore to bring more clarification about potential effects of those processes on the condition of silk samples treated with a set of different parameters for wavelength, pulse duration, energy density and number of pulses per spot. It also looks at the influence of the presence of soiling on the results. The analysis of potential effects was then carried out using statistical methods and advanced analytics. Scanning electron microscopy, Fourier-transform infrared spectroscopy and colorimetry technology provided the required insights to better assess the effects. Results show that laser cleaning of silk fibers, like most other conventional cleaning techniques, is not completely without risk, but knowing what the possible effects are helps making decisions on whether the benefits of the technique used justify these risks. KW - Laser cleaning KW - Cultural heritage KW - Conservation KW - Silk PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594601 DO - https://doi.org/10.1186/s40494-024-01152-1 SN - 2050-7445 VL - 12 IS - 1 SP - 1 EP - 15 PB - Springer AN - OPUS4-59460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Was, G.S. A1 - Bahn, C.-B. A1 - Busby, J. A1 - Cui, B. A1 - Farkas, D. A1 - Gussev, M. A1 - Rigen He, M. A1 - Hesterberg, J. A1 - Jiao, Z. A1 - Johnson, D. A1 - Kuang, W. A1 - McMurtrey, M. A1 - Robertson, I. A1 - Sinjlawi, A. A1 - Song, M. A1 - Stephenson, K. A1 - Sun, K. A1 - Swaminathan, Srinivasan A1 - Wang, M. A1 - West, E. T1 - How irradiation promotes intergranular stress corrosion crack initiation N2 - Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide. KW - Irradiation KW - Stress corrosion cracking KW - Grain boundaries KW - Oxidation KW - Austenitic alloys PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595748 DO - https://doi.org/10.1016/j.pmatsci.2024.101255 SN - 0079-6425 VL - 143 SP - 1 EP - 15 PB - Elsevier AN - OPUS4-59574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Minenkov, Alexey A1 - Hollweger, Sophia A1 - Duchoslav, Jiri A1 - Erdene-Ochir, Otgonbayar A1 - Weise, Matthias A1 - Ermilova, Elena A1 - Hertwig, Andreas A1 - Schiek, Manuela T1 - Monitoring the Electrochemical Failure of Indium Tin Oxide Electrodes via Operando Ellipsometry Complemented by Electron Microscopy and Spectroscopy N2 - Transparent conductive oxides such as indium tin oxide (ITO) are standards for thin film electrodes, providing a synergy of high optical transparency and electrical conductivity. In an electrolytic environment, the determination of an inert electrochemical potential window is crucial to maintain a stable material performance during device operation. We introduce operando ellipsometry, combining cyclic voltammetry (CV) with spectroscopic ellipsometry, as a versatile tool to monitor the evolution of both complete optical (i.e., complex refractive index) and electrical properties under wet electrochemical operational conditions. In particular, we trace the degradation of ITO electrodes caused by electrochemical reduction in a pH-neutral, water-based electrolyte environment during electrochemical cycling. With the onset of hydrogen evolution at negative bias voltages, indium and tin are irreversibly reduced to the metallic state, causing an advancing darkening, i.e., a gradual loss of transparency, with every CV cycle, while the conductivity is mostly conserved over multiple CV cycles. Post-operando analysis reveals the reductive (loss of oxygen) formation of metallic nanodroplets on the surface. The reductive disruption of the ITO electrode happens at the solid–liquid interface and proceeds gradually from the surface to the bottom of the layer, which is evidenced by cross-sectional transmission electron microscopy imaging and complemented by energy-dispersive X-ray spectroscopy mapping. As long as a continuous part of the ITO layer remains at the bottom, the conductivity is largely retained, allowing repeated CV cycling. We consider operando ellipsometry a sensitive and nondestructive tool to monitor early stage material and property changes, either by tracing failure points, controlling intentional processes, or for sensing purposes, making it suitable for various research fields involving solid–liquid interfaces and electrochemical activity. KW - General Materials Science PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597625 DO - https://doi.org/10.1021/acsami.3c17923 SN - 1944-8252 VL - 16 IS - 7 SP - 9517 EP - 9531 PB - American Chemical Society (ACS) AN - OPUS4-59762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knapic, D. A1 - Mardare, A. I. A1 - Voss, Heike A1 - Bonse, Jörn A1 - Hassel, A. W. T1 - Corrosion study of picosecond-laser structured and anodized Ti6Al4V for bone screws N2 - A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond-laser (ps-laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps-laser-treated samples. It is determined that the preanodized and laser-treated sample has 3.5 times larger ECSA than a polished sample, and that the laser-treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser-structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps-laser-treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples. KW - Laser-induced periodic surface structures (LIPSS) KW - Anodization KW - Bone screws KW - Implant material KW - Titanium alloys PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597890 DO - https://doi.org/10.1002/pssa.202300609 SN - 1862-6319 VL - 221 SP - 1 EP - 8 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-59789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nawaz, Q. A1 - Blaeß, Carsten A1 - Mueller, Ralf A1 - Boccaccini, A.R. T1 - Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses N2 - Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches. KW - Bioactive glass KW - Crystallization KW - Solubility KW - Cytocompatibility KW - Surface roughness PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598257 DO - https://doi.org/10.1016/j.oceram.2024.100586 SN - 2666-5395 VL - 18 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-59825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Falkenhagen, Jana A1 - Wachtendorf, Volker A1 - Brüll, Robert A1 - Simon, Franz-Georg T1 - Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios N2 - Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible. KW - Geotextiles KW - Microplastic KW - Size exclusion chromatography KW - Accelerated aging PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599739 DO - https://doi.org/10.3390/su16093559 SN - 2071-1050 VL - 16 IS - 9 SP - 1 EP - 15 PB - MDPI AG CY - Basel AN - OPUS4-59973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -