Wissenschaftliche Artikel der BAM
Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (2083)
- Beitrag zu einem Tagungsband (386)
- Forschungsbericht (19)
- Beitrag zu einem Sammelband (10)
- Sonstiges (10)
- Buchkapitel (9)
- Corrigendum (3)
- Tagungsband (Herausgeberschaft für den kompletten Band) (2)
- Dissertation (1)
- Zeitschriftenheft (Herausgeberschaft für das komplette Heft) (1)
Sprache
- Englisch (2287)
- Deutsch (233)
- Mehrsprachig (3)
- Portugiesisch (1)
Schlagworte
- Additive manufacturing (69)
- Fluorescence (56)
- Nanoparticles (48)
- Concrete (47)
- SAXS (46)
- Ultrasound (38)
- Corrosion (37)
- MALDI-TOF MS (36)
- Quantum yield (36)
- Non-destructive testing (34)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (448)
- 6 Materialchemie (442)
- 1 Analytische Chemie; Referenzmaterialien (361)
- 7 Bauwerkssicherheit (228)
- 5 Werkstofftechnik (216)
- 9 Komponentensicherheit (215)
- 4 Material und Umwelt (197)
- 6.3 Strukturanalytik (168)
- 8.5 Röntgenbildgebung (139)
- 6.1 Oberflächen- und Dünnschichtanalyse (102)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (101)
- 8.0 Abteilungsleitung und andere (100)
- 5.1 Mikrostruktur Design und Degradation (80)
- 9.3 Schweißtechnische Fertigungsverfahren (79)
- 1.2 Biophotonik (74)
- 6.6 Physik und chemische Analytik der Polymere (70)
- 9.4 Integrität von Schweißverbindungen (69)
- 8.4 Akustische und elektromagnetische Verfahren (66)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (64)
- 6.2 Material- und Oberflächentechnologien (63)
- 1.1 Anorganische Spurenanalytik (61)
- 7.4 Baustofftechnologie (61)
- 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (57)
- 1.4 Prozessanalytik (56)
- 4.1 Biologische Materialschädigung und Referenzorganismen (56)
- 1.7 Organische Spuren- und Lebensmittelanalytik (55)
- 3 Gefahrgutumschließungen; Energiespeicher (54)
- 1.5 Proteinanalytik (52)
- 6.0 Abteilungsleitung und andere (51)
- 8.6 Faseroptische Sensorik (50)
- 1.8 Umweltanalytik (43)
- 4.3 Schadstofftransfer und Umwelttechnologien (42)
- 5.2 Metallische Hochtemperaturwerkstoffe (42)
- 7.2 Ingenieurbau (40)
- 1.9 Chemische und optische Sensorik (38)
- 5.4 Multimateriale Fertigungsprozesse (38)
- 9.0 Abteilungsleitung und andere (35)
- 9.2 Versuchsanlagen und Prüftechnik (32)
- 4.2 Material-Mikrobiom Wechselwirkungen (30)
- 5.3 Polymere Verbundwerkstoffe (29)
- 2 Prozess- und Anlagensicherheit (28)
- 4.0 Abteilungsleitung und andere (28)
- 4.5 Kunst- und Kulturgutanalyse (28)
- 5.5 Materialmodellierung (27)
- 5.6 Glas (27)
- S Qualitätsinfrastruktur (27)
- 7.6 Korrosion und Korrosionsschutz (26)
- 2.1 Sicherheit von Energieträgern (25)
- 4.4 Thermochemische Reststoffbehandlung und Wertstoffrückgewinnung (24)
- 9.5 Tribologie und Verschleißschutz (23)
- 9.6 Additive Fertigung metallischer Komponenten (23)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (22)
- VP Vizepräsident (22)
- VP.1 eScience (22)
- 7.1 Baustoffe (21)
- 1.3 Instrumentelle Analytik (19)
- 3.1 Sicherheit von Gefahrgutverpackungen und Batterien (17)
- 5.0 Abteilungsleitung und andere (17)
- 1.6 Anorganische Referenzmaterialien (16)
- S.2 Digitalisierung der Qualitätsinfrastruktur (16)
- 7.7 Modellierung und Simulation (15)
- 1.0 Abteilungsleitung und andere (13)
- 7.0 Abteilungsleitung und andere (13)
- P Präsident (11)
- 3.2 Gefahrguttanks und Unfallmechanik (10)
- 3.5 Sicherheit von Gasspeichern (10)
- P.0 Präsident und andere (10)
- 6.7 Materialsynthese und Design (9)
- 7.3 Brandingenieurwesen (9)
- 6.4 Materialinformatik (8)
- 3.4 Sicherheit von Lagerbehältern (7)
- S.3 Ökodesign und Energieverbrauchskennzeichnung (7)
- 3.6 Elektrochemische Energiematerialien (6)
- S.1 Qualität im Prüfwesen (5)
- 3.0 Abteilungsleitung und andere (4)
- 8.3 Thermografische Verfahren (4)
- 4.6 Molekulare und angewandte Entomologie (3)
- 2.0 Abteilungsleitung und andere (2)
- 2.2 Prozesssimulation (2)
- 2.3 Einstufung von Gefahrstoffen und -gütern (1)
- 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik (1)
- 3.3 Sicherheit von Transportbehältern (1)
- KM Kommunikation, Marketing (1)
- PST Präsidiale Stabsstelle (1)
- VP.2 Informationstechnik (1)
Paper des Monats
- ja (68)
AbstractLithium‐ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur‐based cathodes, offering a high theoretical capacity of 1675 mAh g−1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state‐of‐the‐art sulfur‐based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur‘s mobility leads to battery degradation—an effect known as the “sulfur‐shuttle”. This study introduces a solution by developing a microporous, covalently‐bonded, imine‐based polymer network grown in situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li‐ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1 C (1360 mAh g−1) to 3 C (807 mAh g−1). Demonstrating a high‐performance, sustainable sulfur cathode produced via a simple one‐pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal‐based cathodes.
Multicomponent reactions (MCRs) offer a platform to create different chemical structures and linkages for highly stable covalent organic frameworks (COFs). As an illustrative example, the multicomponent Povarov reaction generates 2,4-phenylquinoline from aldehydes and amines in the presence of electron-rich alkenes. In this study, we introduce a new domino reaction to generate unprecedented 2,3-phenylquinoline COFs in the presence of epoxystyrene. This work thus presents, for the first time, structural isomeric COFs produced by multicomponent domino and Povarov reactions. Furthermore, 2,3-phenylquinolines can undergo a Scholl reaction to form extended aromatic linkages. With this approach, we synthesize two thermally and chemically stable MCR-COFs and two heteropolyaromatic COFs using both domino and in situ domino and Scholl reactions. The structure and properties of these COFs are compared with the corresponding 2,4-phenylquinoline-linked COF and imine-COF, and their activity toward benzene and cyclohexane sorption and separation is investigated. The position of the pendant phenyl groups within the COF pore plays a crucial role in facilitating the industrially important sorption and separation of benzene over cyclohexane. This study opens a new avenue to construct heteropolyaromatic COFs via MCR reactions.
High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
(2024)
AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
Flexible anisotropic magnetoresistive sensors for novel magnetic flux leakage testing capabilities
(2024)
Rigid magnetic field sensors such as anisot Hall sensors have been used for years and have become industry standard for electromagnetic non-destructive testing (NDT). Recent technological developments in the field of flexible electronics allow for the fabrication of reshapeable magnetic field sensors on flexible substrates via thin-film deposition or printing. The magnetic properties of these sensors have comparable characteristics to industry-standard rigid magnetic field sensors, with the added ability of adapting to the surface of complex components and scanning in contact with the sample surface. This improves defect detectability and magnetic signal strength by minimizing the scanning lift-off (LO) distance. In this article flexible AMR sensors mounted on a rotative mechanical holder were used to scan a semi-circular ferromagnetic sample with 3 reference defects via magnetic flux leakage (MFL) testing, thus demonstrating the applicability of this type of sensors for the scanning of curved samples. In order to benchmark the performance of these sensors in comparison to industry standard rigid magnetic field sensors, a ferromagnetic sample with 10 reference defects of different depths was scanned employing flexible AMR and rigid GMR sensors. Defects with depths ranging from 110 μm up to 2240 μm were detected with an signal-tonoise ratio (SNR) of 2.7 up to 27.9 (for flexible AMR sensors) and 6.2 up to 72.3 (for rigid GMR sensors), respectively. A 2D magnetometer mapping of the sample with a spatial scanning step of 10 × 50 μm2 (flexible AMR) and 16 × 100 μm2 (rigid GMR) was obtained. The results show that this type of sensor can be used for high-resolution and high-detail mapping of defects on the surface of planar and non-planar ferromagnetic samples since the scanning lift-off distance is equal to the substrate thickness of 20 μm for in-contact scanning. The SNR comparison between flexible and rigid sensors shows that the performance of the flexible AMR sensors employed is not very far behind the performance of the rigid GMR sensors used.
Here, we report a comparative study of different sum parameter analysis methods for the extraction of per- and polyfluoroalkyl substances (PFAS) from manufactured consumer products, which can be measured by combustion ion chromatography (CIC). Therefore, a hydrolysis-based extraction method was further developed, which accounts for the addition of hydrolyzable covalently bound polyfluoroalkylated side-chain polymers (SFPs) to the extractable organic fluorine portion of the mass balance proposed as "hydrolyzable organically bound fluorine" (HOF). To test this hypothesis, the method was applied to 39 different consumer products containing fluoropolymers or monomeric PFAS taken from four different categories: outdoor textiles, paper packaging, carpeting, and permanent baking sheets. We also evaluated the method's efficiency by extracting four synthesized fluorotelomer polyacrylate reference compounds. The total fluorine (TF) and extractable organically bound fluorine (EOF) values were measured through CIC using established protocols. The TF values ranged from sub-ppb to %-levels, depending on the compound class. All samples showed results for hydrolyzed organofluorine (HOF) between 0.03 and 76.3 μg/g, while most EOF values were lower (<LOD to 58.1 μg/g). Moreover, the methods were contrasted with the "total hydrolyzable precursor" (THP) assay analyzed using gas-chromatography coupled mass spectrometry (GC-MS), which yielded concentrations of 6:2–10:2 fluorotelomer alcohols (<LOD-568 μg/g) for textile and paper samples. Furthermore, targeted analytical investigation of 25 compounds via liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) was conducted and accounted for significantly lower sum amounts (<LOD-0.98 μg PFAS/g). To estimate the fluorine mass balance of all methods, the fluorine levels of target analytical data were calculated and compared to the sum parameter values and evaluated. Finally, the efficiency of the extraction method was approximated by the recovery analysis of four selected SFP model compounds compared to their TF values, yielding 36.7–74.0% after extraction and 3.8–36.3% after processing the extract for the HOF sum parameter.
AbstractPowder Bed Fusion with Laser Beam of Metals (PBF-LB/M) has gained more industrial relevance and already demonstrated applications at a small series scale. However, its widespread adoption in various use cases faces challenges due to the absence of interfaces to established Manufacturing Execution Systems (MES) that support customers in the predominantly data-driven quality assurance. Current state-of-the-art PBF-LB/M machines utilize communication architectures, such as OPC Unified Architecture (OPC UA), Message Queuing Telemetry Transport (MQTT) and Representational State Transfer Application Programming Interface (REST API). In the context of the Reference Architecture Model Industry 4.0 (RAMI 4.0) and the Internet of Things (IoT), the assets, particularly the physical PBF-LB/M machines, already have an integration layer implemented to communicate data such as process states or sensor values. Missing is an MES component acting as a communication and information layer. To address this gap, the proposed Extract Transform Load (ETL) pipeline aims to extract relevant data from the fabrication of each build cycle down to the level of scan vectors and additionally to register process signals. The suggested data schema for archiving each build cycle adheres to all terms defined by ISO/TC 261—Additive Manufacturing (AM). In relation to the measurement frequency, all data are reorganized into entities, such as the AM machine, build cycle, part, layer, and scan vector. These scan vectors are stored in a runtime-independent format, including all metadata, to be valid and traceable. The resulting machine log represents a comprehensive documentation of each build cycle, enabling data-driven quality assurance at process level.
This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters.
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.
Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
Schwefelhexafluorid (SF6) ist ein 22.800-mal stärkeres Treibhausgas als CO2, wird aber aufgrund seiner isolierenden Eigenschaften in Mittel- und Hochspannungssystemen wie Schaltanlagen eingesetzt. Voraussetzung für die Durchschlagfestigkeit ist ein geringer Wasserdampfgehalt. Viele aktuelle Feuchtigkeitssensoren zeigen jedoch eine Querempfindlichkeit gegenüber CO2. Diese Richtlinienarbeit zielt darauf ab, den aktuellen Stand der Technik zu erweitern und neue Erkenntnisse zu gewinnen. Abschließend erfolgt eine Erweiterung der Richtlinie zur Gasfeuchte-Messung VDI/VDE 3514.