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A comprehensive experimental assessment of reinforced concrete walls under blast: In situ monitoring of loading, dynamic response and damage with NDT methods and embedded sensors
No full textA safety or security related assessment of explosions, accidental and intentional scenarios alike, often necessitate performance of resource intensive replication tests. For an efficient assessment without performing full scale blast tests, e.g., supported by numerical simulations, detailed knowledge is necessary to predict the blast loading from a given charge configuration, the resulting dynamic response of the structure under investigation as well as the resulting damage. Validation of numerical simulation requires the spatially resolved acquisition of all these parameters in real time. In this paper we present a set of measurement techniques and discuss their suitability for monitoring reinforced concrete (RC) walls under blast loading. Different blast-loading scenarios were realized by varying the charge weight and the standoff distance. The dynamic loading of the wall was characterized with pressure sensors complemented by numerical simulations using the APOLLO Blastsimulator and ConWep. High speed digital image correlation (DIC) was implemented in combination with multiple acceleration sensors to observe the dynamic deflection of the walls during the loading and to determine the residual deformation after the loading had ceased. In addition, one test specimen was instrumented with fiber optic sensor cables. These fiber optic sensors were used for distributed acoustic sensing (DAS) delivering information on dynamics of compression and tension cycles from within the structure. Additionally, the local damage pattern emerging during the series of blasts was determined via distributed fiber optic strain sensing (DSS) to enable the characterization of visual and non-visual damage to the structure. The obtained information was compared to results by an ultrasound structure-scanner
Interfacial segregation of carbon atoms: the competition between grain boundaries and phase boundaries
No full textThe microstructure of a two-phase medium manganese steel is decorated by interfaces whose character is defined by crystallography and the misorientation between adjacent grains, which in turn influences elemental segregation and shapes the resulting decorations. This study investigates how adjacent grain and phase boundaries impact a boundary’s segregation behavior, with a focus on the competition for carbon (C) enrichment in a laminated ferrite (α)- austenite (γ) microstructure subjected to a series of heat treatments. It was found that semicoherent α-γ Kurdjumov-Sachs (KS) phase boundaries show less carbon segregation than general γ grain boundaries. Furthermore, when a γ grain boundary is present at a junction with the phase boundaries, it acts as an extracting agent for C. DFT calculations support these observations, demonstrating that carbon segregation is energetically more favorable at the γ grain boundary compared to the α/γ phase boundary, due to the more negative segregation energy at the former
Enzyme-Based Electrochemical Detection of Fumonisins Applying Amperometric Sensing
No full textFumonisins represent a class of toxic secondary metabolites produced primarily by Fusarium species, notably F. verticillioides and F. proliferatum, though Aspergillus niger can also produce these mycotoxins. They are most commonly found contaminating maize, but other grains are also at risk. Dietary exposure to fumonisins poses serious health risks to both humans and livestock, prompting the European Commission to set regulatory limits on their presence in food and animal feed. Traditional detection methods, such as chromatography, are often costly, are laboratory based and require specialized expertise. To address the need for simpler, more accessible detection methods, portable electrochemical biosensors present a promising solution. In this study, we introduce a novel enzymatic approach for fumonisin detection using amperometric sensing. Here, a recently discovered fumonisin amine oxidase (AnFAO) from Aspergillus niger, which catalyses the oxidative deamination of fumonisins and generates hydrogen peroxide, was produced recombinantly in Escherichia coli. In our hands, the enzyme exhibited higher specific activity toward Fumonisin B1 compared to Fumonisin B2 at the same substrate concentration (0.0037 U/mg and 0.0014 U/mg at 25 µM substrate, respectively). We demonstrated that enzyme activity correlates with both enzyme and substrate concentrations. To detect Fumonisin B1, the enzyme was covalently attached to magnetic particles, and hydrogen peroxide production was measured amperometrically in a flow injection system with Prussian blue carbon electrodes. This method enabled the quantification of Fumonisin B1 concentrations as low as 1.5 µM and proved that recombinant AnFAO effectively deaminated fumonisins even in its immobilized form. These results highlight AnFAO’s potential for developing an enzyme-based electrochemical biosensor to detect fumonisin contamination in food and feed products
Reference Material (IgG) for CCQM-PAWG Key Comparison
No full textBAM proposes a recombinant human IgG (anti-tetanus monoclonal antibody SA13) as candidate material for the 2027 CCQM-PAWG key comparison on antibody purity. The antibody is produced via hybridoma and recombinant expression systems, with detailed sequence and glycosylation profiling. Analytical methods include MALDI-TOF-MS, SEC, DLS, and UV-vis spectroscopy to assess purity, aggregation, and stability. Preliminary results show high purity, low heterogeneity, and consistent size distribution. A minimum of 40 mg IgG is required, with 100 mg preferred for deeper characterization. Production is expected to be completed by the end of 2026, with potential for a joint technical project
Antikörperbasierte vor-Ort-Analytik für das Monitoring der Eliminierung von Spurenstoffen in Kläranlagen
No full textDie Überwachung der Eliminierung von Spurenstoffen in Kläranlagen, wie sie die Neufassung der Kommunalabwasserrichtlinie vorschreibt, ruft einen Bedarf an vor-Ort-Analytik in den Kläranlagen hervor. Immunanalytische Methoden können vor Ort, z.B. in Form von Schnelltests, durchgeführt werden, ideal aber wären kontinuierlich arbeitende (Immuno-Bio)Sensoren. Antikörperbasierte Verfahren weisen als Flaschenhals immanent die Einschränkung auf, dass pro Analyt ein Antikörper zum Einsatz kommen muss und dass daher nur eine kleinere Anzahl von Substanzen analysiert werden kann. Die Indikatorenliste der Abwasserrichtlinie liefert hier einen Anhaltspunkt. Der Artikel weist schon bisher existierende Schnell- und Hochdurchsatzverfahren aus, ebenso wie Forschungsansätze für eine Sensorik, die online einsetzbar wäre und gibt einen Überblick über Defizite und Entwicklungen
Advanced materials for the energy transition
No full textThe climate crisis is the burning issue of our time. In order to avert the impending consequences, global efforts are being made in a wide variety of social and scientific fields. This report looks at a small part of these efforts, a technical aspect, namely the question of which AdMa are currently considered in techniques to support the energy transition. AdMa, i.e. materials that are rationally designed to have new or enhanced properties, and/or targeted or enhanced structural features, are used in all sectors of the energy transition. Questions of energy generation, storage and saving are considered here. This report is based on literature research and contains a general compilation of various AdMa that are used in the energy transition or are being researched for this purpose. From this compilation, ten materials that are considered particularly relevant for various reasons were selected and examined in more detail in relation to their use. The specific question here lies in the conflicting objective that the development of technologies for the energy transition is welcomed, but the use of AdMa may entail possible challenges in view of chemical safety as well as sustainability and circular economy
Hydrogen diffusion in thick-walled S690 SAW joints: Part 2 - Predictive modeling of welding heat input and microstructure influence
No full textHigh-strength low-alloy (HSLA) steels such as S690 are widely employed in thick-walled welded structures, where hydrogen-assisted cold cracking (HACC) remains a persistent concern. While microstructure-specific hydrogen diffusion coefficients (DH) for weld metal (WM), heat-affected zone (HAZ), and base material (BM) were experimentally established in Part 1 of this study, their quantitative influence on hydrogen accumulation and effusion has not yet been fully clarified. This work presents a transient, spatially resolved numerical model for simulating hydrogen transport in multi-pass submerged arc welds. The model integrates experimentally determined DH values with realistic thermal cycles and temperature-dependent boundary conditions. Developed in Python, the simulation tool is purpose-built for hydrogen diffusion in welded joints and offers a focused, transparent alternative to general-purpose finite element platforms. Parametric analyses demonstrate that, although the diffusion coefficients vary by up to 50 %, their impact on overall hydrogen retention is minor. In contrast, welding parameters such as plate thickness, bead geometry, cooling time (t₈/₅), and interpass tem-perature exert a dominant influence on hydrogen distribution. Despite clear microstructural differences between the thermomechanically rolled (S690MC) and quenched and tempered (S690Q) variants, including hardness softening versus hardening in the heat-affected zone of the (pen)ultimate weld bead, the simulations confirm that their diffusion behavior and hydrogen solubility are closely aligned. Consequently, differences in diffusivity and solubility exert only a minor influence on hydrogen retention compared to thermal exposure and joint geometry. These findings support the interchangeable use of both steel grades in terms of HACC risk due to hydrogen diffusion kinetics, under comparable welding conditions
DGZFP Arbeitskreis Dresden Rissdetektion an Spannbetonschwellen
No full textDieser Bericht fasst die zentralen Ergebnisse eines 18-monatigen Forschungsprojekts zusammen, das sich mit der Entwicklung und Bewertung akustischer Verfahren zur zerstörungsfreien Prüfung von Spannbetonschwellen beschäftigt. Die Laboruntersuchungen wurden an der Bundesanstalt für Materialforschung und -prüfung durchgeführt. Entsprechend der Struktur der definierten Arbeitspakete gliedert sich der Bericht in drei thematische Abschnitte: Zunächst wird der aktuelle Stand der Technik anhand einer umfassenden Literaturrecherche dargestellt, wobei eine Bewertung der verschiedenen Methoden und Verfahren vorgenommen wurde. Dann erfolgt die Beschreibung der umfangreichen Messungen im Labor. Abschließend werden praxisorientierte Konzepte vorgestellt, wie sich die vielversprechendsten Ansätze auf einer Draisine implementieren lassen, um eine mobile und effiziente Prüfung im realen Einsatz zu ermöglichen
Analysis of fluorine/PFAS in battery black mass at HESEB
No full textLithium iron phosphate (LiFePO4) batteries are a safe, cost-effective alternative to traditional lithium-ion batteries, but industrial-scale recycling is not yet available. The recycling process faces challenges, especially in purifying materials like lithium, phosphate, and iron, and managing fluorine contamination from fluoropolymers and salts (including PFAS). Fluorine K-edge XANES spectroscopy was used to analyze the chemical states of fluorine in the recycled materials for a safe reuse of elements and defluorination
Influence of various microalloying strategies on the mechanical properties of weld seams in S690QL steel
No full textMicroalloying elements such as niobium (Nb) and titanium (Ti) play a crucial role in achieving the desired mechanical properties of quenched and tempered high-strength fine-grained structural steels with a nominal yield strength of ≥ 690 MPa. Current specifications for the chemical composition only define upper limits for these elements, providing manufacturers with some flexibility. However, even minor deviations in alloying concepts can significantly influence the resulting mechanical properties. Consequently, accurately predicting weldability and the integrity of welded joints becomes challenging or even unfeasible due to variations in composition and the associated microstructural changes. Potential adverse effects include the softening of the heat-affected zone (HAZ) or, conversely, localized hardening phenomena. To address these challenges, various microalloying strategies with different Ti and Nb contents are being systematically investigated for the first time using specially designed laboratory-cast alloys. Each alloying approach is based on the commonly used S690QL steel grade while maintaining consistent chemical composition and heat treatment parameters