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- ja (93)
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.
The use of ashes from municipal solid waste incineration as secondary building materials is an important pillar for the circular economy in Germany. However, leaching of potential toxic elements from these materials must be at environmentally acceptable levels. Normally, a three-month ageing period immobilizes most hazardous heavy metals, but antimony (Sb) and vanadium (V) showed previously unusual leaching. In order to clarify the mechanisms, we analyzed the Sb and V species in various bottom and fly ashes from municipal waste incineration by XANES spectroscopy. Antimony oxidizes from Sb(+ III) species used as flame retardants in plastics to Sb(+ V) compounds during waste incineration. However, owing to the similarity of different Sb(+ V) compound in the Sb K- and L-edge XANES spectra, it was not possible to accurately identify an exact Sb(+ V) species. Moreover, V is mainly present as oxidation state + V compound in the analyzed ashes. However, the coarse and magnetic fraction of the bottom ashes contain larger amounts of V(+ III) and V(+ IV) compounds which might enter the waste incineration from vanadium carbide containing steel tools. Thus, Sb and V could be critical potential toxic elements in secondary building materials and long-term monitoring of the release should be taken into account in the future.
This research deals with the development of the Vickers hardness knowledge graph, mapping the example dataset in them, and exporting the data-mapped knowledge graph as a machine-readable Resource Description Framework (RDF). Modeling the knowledge graph according to the standardized test procedure and using the appropriate upper-level ontologies were taken into consideration to develop the highly standardized, incorporable, and industrial applicable models. Furthermore, the Ontopanel approach was utilized for mapping the real experimental data in the developed knowledge graphs and the resulting RDF files were successfully evaluated through the SPARQL queries.
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.
AbstractThis study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and dark-field transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology, facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism. The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities.
The stress-induced tetragonal to monoclinic (t-m) zirconia phase transformation can provide a certain degree of plasticity to Ceria-stabilized (Ce-TZP) zirconia-based composites. Characterizing and monitoring this phase transition on a millimeter-size range, within the bulk and in-situ remains a challenge. In this work, the mechanical behavior of Ce-TZP based composite was studied in tension, combining microscopy and synchrotron Xray refraction techniques. In contrast with microscopy methods, which only provide surface information, X-ray refraction radiography (SXRR) allowed the visualization of all the transformation bands, over the entire length and thickness of tested specimens, opening up new avenues for in-situ stress-induced t-m transformation studies.
Liebe Leser*innen,
wir leben in wahrhaft bewegten Zeiten, in einer "Zeitwende" mit all ihren Herausforderungen. Für die Wissenschaft und das, was sie für eine gute Zukunft leisten kann, bedeutet das: Wir müssen Antworten nicht über Verzicht, sondern über intelligente technologische Lösungen finden. Durch ein Wachstum in die Vielfalt und durch die Vielfalt. Wie kann dies gelingen?
Wissenschaft funktioniert nur in offenen, diversen, demokratischen Systemen. Populistische und autoritäre Ansätze dagegen verengen die Räume für fortschrittliche Antworten auf dramatische Weise. Sie verhindern Fantasie für neue Ideen von einer guten Zukunft für alle. Die Eingrenzung der Wissenschaft in ihrer Vielfalt ist darum auch eines der ersten Ziele autoritärer Regierungen. Sie gilt es zu verhindern.
An der BAM arbeiten heute Menschen aus über 50 Ländern, mit vielfältigen Biografien, Zugehörigkeiten und Identitäten. In unseren Laboren, Werkstätten und in unserer Verwaltung leisten sie Großartiges. Ohne ihre Arbeit könnte die BAM nicht ihren Auftrag, die Sicherheit in Technik und Chemie zu gewähren, erfüllen. Weltoffenheit, Diversität, Vernetzung und internationaler Austausch sind unsere Grundwerte und Erfolgsfaktoren für die BAM.
Gemeinsam mit Wissenschaftler*innen aus Namibia forschen wir an sicheren Infrastrukturen für eine zukünftige Wasserstoffwirtschaft - eine Kooperation, von der beide Seiten profitieren. Ein international besetztes BAM-Spin-off entwickelt eine revolutionäre Schweißtechnik, mit der der Windenergieausbau beschleunigt werden kann. In interdisziplinär zusammengesetzten Teams entwickeln wir Referenzmaterialien für noch leistungsfähigere E-Akkus. Und mithilfe von Methoden des maschinellen Lernens und künstlicher Intelligenz beschleunigen Mitarbeitende der BAM mit vielfältigen fachlichen wie kulturellen Hintergründen die Entwicklung neuer, maßgeschneiderter Werkstoffe. Allesamt Projekte, bei denen Vielfalt ein wichtiges und unverzichtbares Element darstellt.
Im neuen BAM Report 2023/24 stellen wir Ihnen diese und viele weitere aktuelle Projekte der BAM vor. Ich würde mich freuen, wenn sich daraus weitere Ideen ergeben, wie wir zusammen die Zukunft sicherer gestalten können. Aber auch, wenn Ideen für Initiativen entstehen, wie wir Vielfalt, Demokratie und Offenheit weiter ausbauen und fördern können - zum Nutzen aller. Lassen Sie uns hierzu gerne in den Dialog kommen.
Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
(2024)
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.
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.
Adhesively bonded composite joints can develop voids and porosity during fabrication, leading to stress concentration and a reduced load-carrying capacity. Hence, adhesive porosity analysis during the fabrication is crucial to ensure the required quality and reliability. Ultrasonic-guided wave (UGW)-based techniques without advanced signal processing often provide low-resolution imaging and can be ineffective for detecting small-size defects. This article proposes a damage imaging process for adhesive porosity analysis of bonded composite plates using UGWs measured by scanning laser Doppler vibrometer (LDV). To implement this approach, a piezoelectric transducer is mounted on the composite joint specimen to generate UGWs, which are measured over a densely sampled area. The signals obtained from the scan are processed using the proposed signal processing in different domains. Through the utilization of filter banks in frequency and wavenumber domains, along with the root-mean-square calculation of filtered signals, damage images of the adhesive region are obtained. It has been observed that different filters provide information related to different void sizes. Combining all the images reconstructed by filters, a final image is obtained which contains damages of various sizes. The images obtained by the proposed method are verified by radiography results and the porosity analysis is presented. The results indicate that the proposed methodology can detect the pores with the smallest detectable pore area of 2.41 mm^2, corresponding to a radius of 0.88 mm, with an overall tendency to overestimate the pore size by an average of 11%.