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Harmonizing Viscoplastic Material Model Application within the BMBF-Project “DigitalModelling” of the Platform Material Digital- Basic Idea, General Strategy and Current Status
No full textFor decades, Germany stands for excellent cutting-edge research in the field of so-called higher-value constitutive visco-plastic material models and can draw on a large and globally unique pool of material data. However, both the data and the model structure are extremely heterogeneous and sometimes fundamentally different from research center to research center and from industrial partner to industrial partner. To address the heterogeneity in the material model landscape appropriately, an adaptable material model for the specific application and the specific material is required. The relevant parameters for the adapted material model must be identified as objectively and automatically as possible. To achieve a potentially real-time capable implementation, the material model equation system should be abstracted.
The “DigitalModeling” project, organized within the German Platform initiative Material Digital, aims to create a standard and an interface that harmonize the scientific and technical development of constitutive, visco-plastic material models, increase their visibility and maximize the productivity of future research funding. This presentation summarizes the basic idea, the strategy behind it as well as the current status of the project, which was started beginning of 2024
Die Aufgaben der BAM im Gefahrgutbereich - ein Überblick
No full textDie BAM ist eine der zuständigen Behörden im Gefahrgutbereich in Deutschland und nach der Gefahrgutverordnung Straße, Eisenbahn und Binnenschifffahrt (GGVSEB) und der Gefahrgutverordnung See (GGVSee) für diverse Aufgaben zuständig, wie z. B. große Teile der Klassifizierung gefährlicher Güter, die Verwendung, Prüfung, und Zulassung von Gefahrgutverpackungen oder auch die Verwendung, den Bau und die Prüfung von Gefahrguttanks. Sie berät die Bundesregierung bei der Ausrichtung der Gefahrgutpolitik durch Mitarbeit im Ständigen Ausschuss Gefahrgutbeförderung (AGGB) des Gefahrgut-Verkehrs-Beirates beim BMV und wirkt nach dem Erlass über die BAM im Einvernehmen mit dem BMWK in nationalen und internationalen Regel setzenden Gremien und Normungsgremien mit. Damit leistet sie einen wertvollen Beitrag zur Sicherheit im Gefahrgutbereich
Current status of monitoring of PFAS release from industrial facilities
No full textIncreasing studies report per- and polyfluoroalkyl substances (PFAS) in the ambient air and emissions from diverse industrial sources. Therefore, a comprehensive framework for characterizing PFAS emissions by identifying source-specific chemical fingerprints, evaluating emission pathways and assessing the impact of remediation technologies is needed. Depending on the type of PFAS, dedicated sampling and analytical procedures are required. Here, also the detection of possible PFAS transformation products, so-called products of incomplete combustion (PICs) are more mobile or toxic, is also of great interest to evaluate these technologies in terms of mineralisation potential and fluorine mass balance
Standardized Chemical Composition Analysis of Graphene Oxide Flakes with SEM/EDS and XPS Works Reliably
No full textReliable quantification of the chemical composition of graphene-related 2D materials as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended to be used in ongoing projects at standardization bodies. The specific parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1]. In this contribution, for the first time, the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. It is expected that the quantitative EDS analysis of light elements emitting characteristic X-ray lines below 1 keV to be provided with significantly larger measurement uncertainties than the analysis of elements with an atomic number of 11 (Na) or above [3]. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [4], which has been carried out on the same samples.
A crucial step in sample preparation from liquid suspension with graphene oxides flakes onto a substrate for analysis with both XPS and EDS. It is demonstrated that if a closed and enough thick drop-cast deposited spot is succeeded to be deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterizing EDS result in very similar elemental composition of oxygen and carbon. Hence, theoretical, expected O/C atomic ratio values for pure graphene oxide of ~0.5 [1] are achieved (with both methods), see Figure 1. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. To note that all the EDS results in this study have been quantified standardless.
The effect of the variation of beam voltage on the result of the quantification of the O/C ratio is shown in Figure 2. No clear tendency is visible by varying the kV, which is a confirmation of the quality of the standardless analysis at the used EDS spectrometer.
The results of this study demonstrate the reliability of the reference measurement protocol for SEM/EDS to be introduced into ISO/DTS 23359, including the dedicated sample preparation, particularly for the cases when the concentration of the GO flakes in stock liquid suspension is low. Further, also the consideration of this GO material as one of the very few available as a commercial material on the market as the very first GO reference material with regard to its morphology as well as chemical composition. Both the standard measurement procedure and the candidate reference material will immensely contribute to characterise reliably the chemical composition of graphene-related 2D materials with SEM/EDS as one of the most widely used methods in analytical laboratories
AMVAD - Additive manufacturing for ventricular assist devices
No full textSome children are born with a univentricular heart, meaning their heart has only one pumping chamber instead of two. To improve circulation, patients often undergo the Fontan procedure, which reroutes blood flow — but this can put stress on other organs. In some cases, ventricular assist devices, or VADs, are used to support the heart’s pumping function. This involves an artificial pump connected directly to the patient's heart via silicone-based cannulas. Unique anatomical conditions introduce special challenges for cannula geometry. Additive manufacturing offers innovative solutions by enabling the production of personalized medical devices. The aim of the project is to develop the manufacturing workflow for the individualized cannula from digital imaging of the patient and customized design to additive manufacturing. Besides technical feasibility, validating the entire process is crucial for regulatory approval. The selection and testing of suitable additive manufacturing processes and biocompatible materials for individualized silicone cannulas, ensuring compliance with quality standards for high-risk medical products, will be presented
A New Young Network - die junge gfkorr (Das Netzwerk für junge Korrosionisten)
No full textThis invited talk at the Young EFC Meeting (European Federation of Corrosion) was about the new network, founded in Germany in 2023, specialising in corrosion and corrosion protection. The network is called "die junge gfkorr" and has the following aims: (i) Initiation of in-person events with excursions and a networking atmosphere. (ii) Members come from both industry and academia can find similarities in each other's work (iii) Get to know each other and learn from each other, and (iv) Members benefit long-term by using the network throughout their careers and for future collaboration on daily business and research projects
Bayesian Optimization of flame-retardant performance in a high-Tg epoxy resin system
No full textPolymeric materials are widely used due to their mechanical properties and cost-effectiveness, but their inherent flammability requires effective flame-retardant additives to meet safety standards. Optimizing multicomponent flame-retardant formulations is challenging due to the vast experimental space. This study applies Bayesian Optimization (BO) to optimize flame-retardant formulations in high glass transition temperature (Tg) epoxy resins. Aluminum diethyl phosphinate (AlPi) was systematically combined with three synergists: zinc stannate (ZnSt), a silicone-based additive (DowSil), and low-melting glass frits (Ceepree). BO-guided experimental design expanded from 16 initial formulations to a total of 28, minimizing the Maximum Average Rate of Heat Emission (MARHE) under the constraint of Total Smoke Production (TSP) < 17 m2 using the epsilon-constraint method. BO revealed non-linear synergistic interactions: ZnSt significantly reduced smoke production while AlPi effectively lowered heat release. The optimized formulation (BO7) achieved the lowest MARHE (122 kW/m2) while maintaining acceptable smoke levels, establishing a new Pareto front. The results demonstrate the effectiveness of BO in accelerating the development of synergistic, halogen-free flame-retardant polymer systems, offering a scalable and sustainable approach to polymer formulation design
Diffraction based residual stress analysis: challenges and opportunities in additive manufacturing
No full textThis presentation overviews the challanges and opportunities of diffraction based residual stress analysis for additively manufactured metals. Through examples, the challanges and respective solutions are presented and the opportunities that the presented methods allow are described
Elemental mapping to study the interaction of MRI contrast agents with extracellular matrix components
No full textNon-specific Gd-based contrast agents (GBCAs) have long been routinely used in clinical magnetic resonance imaging (MRI) diagnostics. Nevertheless, the interaction of such contrast agents with tissue components is not yet fully understood. Typically, they go into extracellular space. The extracellular matrix (ECM) is a three-dimensional network of macromolecules providing structural and biochemical support of the surrounding cells in all mammalian tissues. It is composed of structural proteins (e.g., collagen, elastin) and proteoglycans, which consist of glycosaminoglycans (GAGs) covalently bound to a protein core. GAGs are long, linear polysaccharides composed of repeating disaccharide units that differ in molecular mass, disaccharide structure and degree of sulfation. Many diseases, including inflammation, fibrosis, and tumor invasion, are associated with characteristic ECM changes, especially at an early stage of disease development. As disease severity increases, the amount of one or more different GAG types in the ECM and the extent of GAG sulfation increases. Characteristic of GAGs is their ability to form complexes with cations, e.g., with lanthanides. Thus, GAGs could be a potential binding partner for GBCA molecules as a whole or for dechelated Gd. Currently, there are still many unanswered questions about the interaction of contrast agents with ECM components. In this study, therefore, the uptake and distribution of ionic Gd and various linear and macrocyclic GBCAs was investigated in spheroids as model systems mimicking the complex physiologically relevant tissue microenvironment. Chinese hamster ovary (CHO) cells and CRL-2242 cells, a CHO mutant that does not produce sulfated GAGs, were used to prepare spheroids. Afterwards the spheroids were incubated with gadolinium chloride and GBCAs. For elemental mapping laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS) and synchrotron radiation nano X-ray fluorescence spectroscopy (syn-nanoXRF) were used. Although all spheroids were exposed to identical Gd concentrations, differences were observed in the spatial distribution and the amount of Gd taken up. After incubation with linear and macrocyclic GBCAs, Gd is detected in the interior of both types of spheroids. Furthermore, differences in the Gd amount were found depending on the GBCA used. In contrast, incubation with gadolinium chloride leads to an Gd enrichment in the outer regions of the spheroids as well as to much higher Gd contents compared to incubation with GBCAs. Both LA-ICP-TOFMS and syn-nanoXRF can make an important contribution to better understand the relationship between the affinity of GBCAs and ECM components. However, to elucidate such complex interactions, further studies are needed, also with other (bio-)analytical techniques
Total Focusing in the Virtual Wave Domain: 3D Defect Reconstruction using spatially structured Laser Heating
No full textClassical active thermographic testing of industrial goods has mostly been limited to generating 2D defect maps. While for surface or near-surface defect detection, this is a desired result, for deeply buried defects, a 3D reconstruction of the defect geometry is coveted. This general trend can also be well observed in widely used NDT methods (radiography, ultrasonic testing), where the progression from 2D to 3D reconstruction methods has already made profound progress (CT, UT phased array transducers). Achieving a fully 3D defect reconstruction in active thermographic testing suffers from the diffusive nature of thermal processes. One possible solution to deal with thermal diffusion is the application of the virtual-wave concept, which, by solving an inverse problem, allows the diffusiveness to be extracted from the thermographic data in the post-processing stage. What is left follows propagating-wave physics, enabling the usage of well-known algorithms from ultrasonic testing. In this work, we present our progress in the 3D reconstruction of deeply buried defects using spatially structured laser heating in conjunction with applying the well-known total focusing method (TFM) in the virtual-wave domain