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Following directly from the information presented at IFBIC 2023 on the research project 'Investigation of intracorporeal shock wave propagation using a simplified torso model and a shock wave generator', the latest results are presented below [1]. In order to contribute to the research efforts on the primary explosion effects, the aim of the investigation is the development of a multidisciplinary method to investigate shock wave behavior in various generic tissue simulants under the most reproducible conditions possible with realistic loads in an experimental series with short set-up times.
To achieve this, an autoclave with a volume of 0.065 m3 is used to generate reproducible pressure waves (Fig. 1). The autoclave will be referred to as Shockwave Generator (SWG). The pressure wave is produced by the detonation of a stoichiometric mixture of acetylene and oxygen under atmospheric conditions. The SWG-outlet is sealed by a rupture disc, which can be adjusted in thickness to vary the initial pressure. Additionally, modifying the composition of the acetylene-oxygen mixture can result in different load cases. The SWG requires approximately 30 minutes of set-up time between trials. The SWG was adjusted to match the characteristics of a real and typical explosive through free-field measurements. The experiments demonstrated that the pressure wave propagates in a hemispherical shape and has sufficient reproducibility.
To represent soft tissue, a basic model made of homogeneous ballistic gelatin is used in a geometrically simplified torso model (STM) (Fig. 2). The STM was enlarged to outer dimensions of 400 x 250 x 240 mm. Viscoelastic behavior of the ballistic gelatin can be assumed due to the collagen structure [2]. The density of the ballistic gelatin, and therefore the sound velocity, can be adjusted by changing the mixing ratio. Simplified simulants, such as hollow and solid material (bone simulant), were embedded in the STM. Additionally, the STM has been tested as a carrier material for biological substances, such as indicator species. The next step is to test the STM as a carrier material for larger organic tissue structures such as lungs or kidneys. The organic tissue samples will undergo histological examination to analyze their structural changes afterwards. The STM is equipped with embedded piezoelectric pressure sensors, an accelerometer and a temperature sensor. Visual documentation is captured using a high-speed camera. This measurement setup allows for the tracking of the coupled pressure wave and its behavior within the model and at the media transitions. Pressure values can be recorded after certain media changes, such as from soft tissue to a solid material (Figure 3).
The following is a review of the optimizations made to the entire experimental setup. The reproducibility of the SWG was increased. This was achieved by extending the evacuation process to the entire feed system of the SWG. Nitrogen residues in the SWG system can thus be avoided. As a result, the double peaks that occur at the first maximum can be avoided, as combustion runs more evenly without the nitrogen residues. In addition, partially varying peak overpressures can be avoided, as the acytelene-oxygen mixture is not too lean due to the elimination of the nitrogen residues. The workflow has been streamlined, resulting in an average set-up time of 25 minutes for the SWG. In the case of the STM, the manufacturing process in particular was optimized by examining and defining the manufacturing process based on scientific publications, which increases the reproducibility of the STM base bodies. As already mentioned in the previous paragraph, the STM was equipped with various additives in order to investigate the transition behavior of the pressure wave.
The following trail serves as an example: A comparison is made between the STM in the basic structure (Fig. 2 l.s.) and with an embedded solid material (bone plate) (Fig. 3 l.s.). An external overpressure of 100 kPa is generated by the SWG at a distance of 1 m, where the STM is placed. For the basic STM structure, the sensor distance is consistently 100 mm. The internal overpressure is visible in Fig. 2 r.s.. A typical ideal pressure curve can be seen. The characteristic points are easily distinguishable from the reflection peaks. In the STM with an embedded solid material, the sensor distance remains consistently at 66.6 mm
Preliminary results of an interlaboratory comparison on microplastics organised by plasticsfate
(2023)
Microplastics are everywhere in the environment, but analytics is challenging. Since harmonisation is missing as well es suitable reference materials, BAM did under th umbrella of VAMAS funded by the EU Horizon 2020 project PlasticsFate a ILC for microplastic detection methods. Methods adressed were IR, Raman, Py-GC/MS and TED-GC/MS. The talk gives a first presentation and evaluation on the results.
Die Probenpräparation ist ein wichtiger Schritt für die Qualität der Massenspektren in MALDI-TOF MS. Es werden Polymerproben, die lösungsmittelbasiert und lösungsmittelfrei präpariert worden sind, verglichen. Dabei werden die Intensitätsverhältnisse von ternären Mischungen von PEG-, PS- und PMMA-Polymeren beachtet.
MALDI TOF Massenspektrometrie wurde verwendet, um Kristallisationsprozesse in Polyestern (Polylactide, Polyglycolide) zu untersuchen. Dabei konnte gezeigt werden, dass Zyklen und Linearen simultan, aber in unterschiedlichen Kristalliten, kristallisieren. Die dabei ablaufenden Umesterungen (Transesterifizierungen) konnten mit der MALDI TOF Massenspektrometrie nachgewiesen werden. Damit wurde ein völlig neues Anwendungsgebiet dieser MS Methode demonstriert.
An Amorphous Lewis-acidic Zirconium Chlorofluoride as HF Shuttle: C-F Bond Activation and Formation
(2024)
In recent years, fluorine chemistry has gained increasing political attention. Owing to a growing shortage of fluorspar, a raw material used for producing fluorinated base chemicals, fluorospar has been named among the 30 critical raw materials in the EU.2 As such, it becomes increasingly important to recycle existing fluorinated compounds and make them available as sources of fluorine for reactions. Significant progress has been made in the field of C-F bond activation using heterogeneous catalysts such as aluminum chlorofluoride (ACF).3–5 However, the transfer of fluorine atoms from one molecule to another using heterogeneous catalysts has not yet been reported. In this study, we successfully synthesized amorphous zirconium chlorofluoride (ZCF), and we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present a heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
Owing to a growing shortage of fluorspar, a raw material used for producing fluorinated base chemicals, fluorspar has been named among the 30 critical raw materials in the EU. 1 However, the sustainable transfer of fluorine atoms from one molecule to another using heterogeneous catalysts has not yet been reported. Herein, we present the heterogeneous catalyst zirconium chloro fluoride (ZCF) that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
Microplastic reference material is required for validation and harmonization purposes. This includes the analysis of the pure polymer particles and the validation of the respective measurement methods. In addition, there is the harmonization of different laboratories. On the other hand, sample preparation methods must be validated and harmonized with regard to their recovery and subsequent analysis in the respective matrices. For this purpose, we produce reference material candidates in the form of tablets with different mass fractions and particle numbers of polyethelene terephthalate. In the presentation first measurement results by µ-Raman, µ-FTIR, pyrolysis-GC-MS and TED-GC/MS will be presented.
Die laserbasierte aktive thermografische Prüfung als berührungslose Methode der zerstörungsfreien Werkstoffprüfung (NDT) basiert auf der aktiven Erwärmung des Testobjekts (OuT) und Messung des resultierenden Temperaturanstiegs mit einer Infrarotkamera. Dadurch bedingt können systematische Abweichungen vom vorhergesagten Erwärmungsverhalten Aufschluss über dessen innere Struktur geben. Jedoch ist das Auflösungsvermögen für innenliegende Defekte durch die diffusive Natur der Wärmeleitung in Festkörpern begrenzt. Thermografische Super-Resolution (SR)-Methoden zielen darauf ab, diese Limitation durch die Kombination mehrerer Messungen mit jeweils unterschiedlicher strukturierter Erwärmung und mathematischer Optimierungsmethoden zu überwinden.
Zur Rekonstruktion innerer Defekte mithilfe thermografischer SR-Rekonstruktionsmethodik wird für die Gesamtheit mehrerer Messungen ein schlecht gestelltes und stark regularisiertes inverses mathematisches Problem gelöst, was in einer dünnbesetzten Karte der internen Defektstruktur des OuTs resultiert.
Der vorliegende Vortrag gibt einen Überblick über die geleisteten Arbeiten in diesem Gebiet im Rahmen der hier mit dem Wissenschaftspreis der DGZfP 2024 prämierten Arbeit.
The variability and heterogeneity in their structural composition is significant for nearly all synthetic and natural polymers. Beside molar mass also functionality type distribution, copolymer composition distribution and architectural features are responsible for changing the material properties.
A wide range of analytical techniques are available to get insight into these parameters. However, in most cases it is essential to combine different sophisticated techniques to get closer to actual structures and to avoid statistical averages.
Different liquid chromatographic separation modes and their coupling in a two-dimensional way (SEC, LCCC, HILIC, 2D-LC) in combination with suitable detection techniques (e.g. UV, RI, LS, IR, MALDI/ESI-MS) as well as techniques like BET, DCS, SEM/TEM were applied to make structural features visible.
A few aspects are discussed for structural different polylactides from various synthesis routes and their behavior in LC-MS.
Im Rahmen des Vortrags wurden die Ergebnisse und die Methodik zur Erhebung von Forschungsbedarfen und Fähigkeitslücken bei den Behörden und Organisationen mit Sicherheitsaufgaben, welche im Rahmen des Projektes InnoBOSK durchgeführt wurden, vorgestellt. Den Schwerpunkt bildete dabei die Umsetzung der Workshops gemeinsam mit den Einsatzkräften und die Umsetzung der problemorientierten Erhebungsmethodik.
This study explores the acceleration of material design in the concrete industry, focusing on improving carbonation resistance, a key factor in the durability of concrete structures. Traditional tests for carbonation resistance are lengthy, but with the construction industry aiming for sustainable production, finding a balance between carbonation resistance and CO2 footprint is crucial. Our research employs two innovative methods: 1. Applying the Sequential Learning App for Materials Discovery (SLAMD), an AI materials design framework, to an extensive dataset of real-world concrete compositions to selectively test materials that meet market demands: maximum durability, optimal eco-durability, and the best cost-durability trade-off. 2. Investigating 1H Nuclear Magnetic Resonance (NMR) relaxometry as a quick alternative for characterizing carbonation behavior, as it saves time compared to traditional tests and assesses the complete material's pore space. Specific NMR features are then integrated into the material design model, with the model's performance compared against traditional approaches. The results of our study are compelling, demonstrating that materials can be precisely tailored to meet specific requirements with minimal data points. This marks a significant stride in the concrete industry, indicating that NMR-based, low-fidelity surrogate characterizations, combined with a focused, data-driven design approach, can substantially accelerate the development of durable, sustainable concrete mixtures.
The presentations discusses a use case for the optimization of concrete structures where structural and material design are integrated in a computational workflow. The workflow is based on both physics-based and data-based models and experimental data is used to calibrate/train these models with a specific focus on the integration of ucertainties.
In recent years, many protocols in computational materials science have been automated and made available within software packages (primarily Python-based). This ranges from the automation of simple heuristics (oxidation states, coordination environments) to the automation of protocols, including multiple DFT and post-processing tools such as (an)harmonic phonon computations or bonding analysis. Such developments also shorten the time frames of projects after such developments have been made available and open new possibilities. For example, we can now easily make data-driven tests of well-known rules and heuristics or develop quantum chemistry-based materials descriptors for machine learning approaches. These tests and descriptors can have applications related to magnetic ground state predictions of materials relevant for spintronic applications or for predicting thermal properties relevant for thermal management in electronics. Combining high-throughput ab initio computations with fitting, fine-tuning machine learning models and predictions of such models within complex workflows is also possible and promises further acceleration in the field. In this talk, I will show our latest efforts to link automation with data-driven chemistry and materials science.
Im Rahmen eines vom Umweltbundesamt geförderten Forschungsprojekts wurde untersucht, ob die Abtrennung der Feinfraktion (0-2 mm) eine Verbesserung der umweltrelevanten Eigenschaften bewirkt und somit HMVA-1 erreicht werden kann. In Deutschland wird die Rostasche durch Nassentschlackungssysteme aus dem Feuerraum ausgetragen. Durch den Kontakt mit Wasser setzen direkt hydraulische Reaktionen ein, die eine vollständige Abtrennung der Feinfraktion unmöglich machen. Das wurde bereits in den 1990er Jahren erkannt und führte zur Entwicklung des ABB InRec Verfahrens mit Trockenentaschung als ersten Verfahrensschritt. Auch damals war das Ziel eine möglichst inerte Rostasche für die Verwertung zu erzeugen. In den letzten Jahren wurden in der Schweiz Trockenentaschungssystem installiert, hier vor allem um die Rückgewinnung von elementaren Metallen auch in der Feinfraktion zu verbessern. Welche Potenziale sich dabei erschließen lassen, wurde in einem anderen UBA-Projekt untersucht. Im Rahmen unserer Arbeiten wurde versuchsweise trockene Rostasche an einer Anlage in Süddeutschland genommen und im Labor untersucht. Im Vortrag werden die Ergebnisse zum Auslaugverhalten und zur Gefahreneigenschaft HP14 (Ökotoxizität) vorgestellt.
This study aims to represent an approach for transferring the materials testing datasets to the digital schema that meets the prerequisites of the semantic web. As a use case, the tensile stress relaxation testing method was evaluated and the testing datasets for several copper alloys were prepared. The tensile stress relaxation testing ontology (TSRTO) was modeled following the test standard requirements and by utilizing the appropriate upper-level ontologies. Eventually, mapping the testing datasets into the knowledge graph and converting the data-mapped graphs to the machine-readable Resource Description Framework (RDF) schema led to the preparation of the digital version of testing data which can be efficiently queried on the web.
The presentation gives an overview of BAM's activities on processing influences and application properties of MPEAs in the form of joined and machined high and medium entropy alloys (CoCrFeMnNi and CoCrNi). In the case of welding, the focus is on defect-free welded joints with sufficient mechanical properties. In the case of machining, the focus is on the possible influence on the surface quality of the materials through adequate milling parameters. In addition, the hydrogen absorption and diffusion properties as well as the electrochemical corrosion behavior are fundamentally examined.
Aktive thermografische Prüfung ist ein vielseitiges Instrument in der Familie der zerstörungsfreien Prüfverfahren. Der Einzug moderner Lasertechnologie hat hier bedeutende neue Anwendungsfelder eröffnet. In Kombination mit Industrierobotik können nun beispielsweise beliebig komplex geformte Bauteile großflächig vollautomatisiert auf Oberflächenrisse überprüft werden. Der hier vorliegende Vortrag gibt einen Überblick über die Grundlagen der Laserthermografie, zeigt unsere Anstrengungen am Fachbereich im Bereich der automatisierten thermografischen Detektion von Oberflächenrissen und gibt ein Ausblick über neue moderne Thermografieverfahren aus der Forschung.
The heat-resistant cast iron EN-GJSA-XNiSiCr35-5-2 (Ni-Resist D-5S) was investigated for its fatigue crack growth behavior at room and high temperatures. Force-controlled tests were carried out at constant temperatures (20 °C, 500 °C, 700 °C) without and with hold time and different load ratios. The crack growth behavior was also characterized under TMF loading (Tmin = 400 °C, Tmax = 700 °C) by applying IP and OP conditions and different load ratios. Three different techniques were combined to monitor crack growth: potential drop, thermography, and compliance method. The effect of the different loading conditions on the fatigue crack growth behavior will be presented and discussed.