TY - JOUR
A1 - Arinchtein, A.
A1 - Ye, M.-Y.
A1 - Yang, Q.
A1 - Kreyenschulte, C.
A1 - Wagner, Andreas
A1 - Frisch, M.
A1 - Brückner, A.
A1 - Kondratenko, E.
A1 - Kraehnert, R.
T1 - Dynamics of Reaction-Induced Changes of Model-Type Iron Oxide Phases in the CO2-Fischer-Tropsch-Synthesis
N2 - Iron-based catalysts are employed in CO2-FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2-FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2-FTS atmospheres at 20 bar and 300°C. Up to three distinct phases were observed depending on the timeon-stream (TOS): a sintered maghemite/magnetite phase, a carbidic core-shell structure, and a low-crystalline, needle-type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase.
Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed.
KW - Nanostructured FeOx films
KW - CO2
KW - Scanning Auger Spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549709
DO - https://doi.org/10.1002/cctc.202200240
SN - 1867-3880
VL - 14
IS - 14
SP - 1
EP - 11
PB - Wiley-VCH
AN - OPUS4-54970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhao, H.
A1 - Chakraborty, Poulami
A1 - Ponge, D.
A1 - Hickel, Tilmann
A1 - Sun, B.
A1 - Wu, C.-H.
A1 - Gault, B.
A1 - Raabe, D.
T1 - Hydrogen trapping and embrittlement in high-strength Al alloys
N2 - Ever more stringent regulations on greenhouse gas emissions from transportation motivate efforts to revisit materials used for vehicles. High-strength aluminium alloys often used in aircrafts could help reduce the weight of automobiles, but are susceptible to environmental degradation. Hydrogen ‘embrittlement’ is often indicated as the main culprit; however, the exact mechanisms underpinning failure are not precisely known: atomic-scale analysis of H inside an alloy remains a challenge, and this prevents deploying alloy design strategies to enhance the durability of the materials. Here we performed near-atomic-scale analysis of H trapped in second-phase particles and at grain boundaries in a high-strength 7xxx Al alloy. We used these observations to guide atomistic ab initio calculations, which show that the co-segregation of alloying elements and H favours grain boundary decohesion, and the strong partitioning of H into the second-phase particles removes solute H from the matrix, hence preventing H embrittlement. Our insights further advance the mechanistic understanding of H-assisted embrittlement in Al alloys, emphasizing the role of H traps in minimizing cracking and guiding new alloy design.
KW - Atomistic models
KW - Hydrogen
KW - Metals and alloys
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543631
DO - https://doi.org/10.1038/s41586-021-04343-z
SN - 1476-4687
VL - 602
IS - 7897
SP - 437
EP - 441
PB - Nature Publ. Group
CY - London
AN - OPUS4-54363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Schaumann, P.
A1 - Hothan, Sascha
A1 - Mund, M.
A1 - Häßler, Dustin
A1 - Schartel, Bernhard
A1 - Daus, Lars-Hendrik
T1 - Bewertung des Feuerwiderstandes von Stahlkonstruktionen mit reaktiven Brandschutzsystemen unter Berücksichtigung des Alterungsverhaltens
N2 - Im Rahmen des Forschungsprojektes IGF 20470N wurden Untersuchungen zum Alterungsverhalten von reaktiven Brandschutzsystemen (RBS) auf Stahlbauteilen durchgeführt. Mithilfe der Ergebnisse einer umfangreichen Literaturrecherche sowie experimentellen und numerischen Untersuchungen sollte ein Vorschlag für ein Prüfkonzept zum Nachweis einer Nutzungsdauer von RBS von mehr als 10 Jahren auf Basis von Kurzzeitversuchen abgeleitet werden. Dabei setzt die Bewertung des Alterungsverhaltens von RBS voraus, dass die Mechanismen der Alterung hinreichend bekannt sind.
Dafür wurden zunächst systematisch Daten von Kurz- und Langzeitversuchen von nationalen Zulassungsprüfungen der letzten Jahrzehnte ausgewertet. Anschließend wurden umfangreiche experimentelle Untersuchungen an einer wasserbasierten sowie einer epoxidharzbasierten Richtrezeptur durchgeführt. Da aus der Literatur bekannt ist, dass die Einflüsse der Bewitterung zu einer Veränderung der Konzentration der Bestandteile innerhalb der Beschichtung führen können, wurden Untersuchungen mit Mangelrezepturen durchgeführt, wobei systematisch einzelne Bestandteile reduziert wurden. Neben optischen Untersuchungen wurden thermoanalytische Verfahren (DSC-TG-, ATR-FTIR-, Elementar-, Farbanalyse) angewandt sowie Brandversuche an beschichteten Stahlplatten durchgeführt. Des Weiteren wurden die Richtrezepturen den beschleunigten Kurzzeitversuchen gemäß EAD 350402-00-1106 (2017) unterzogen, welche die Zulassung von Produkten auf europäischer Ebene regelt. Für die wasserbasierte Richtrezeptur wurden die Bewitterung für den feuchten Innenraum (Typ Z1) mehrfach wiederholt (1x, 3x, 6x). Für die epoxidharzbasierte Richtrezeptur entsprach die Bewitterung dem Zyklus für die Außenanwendung (Typ X). In Brandversuchen sowie thermoanalytischen und optischen Untersuchungen wurde das Alterungsverhalten sowie die thermische Schutzwirkung analysiert.
Anschließend wurden numerische Simulationen von Stahlbauteilen mit gealterten RBS durchgeführt und anhand der experimentellen Untersuchungen validiert. Mithilfe der numerischen Modelle kann eine Bewertung der thermischen Schutzwirkung von Stahlbauteilen mit gealterten RBS vorgenommen werden.
Mithilfe der gesammelten Erkenntnisse wurde ein Vorschlag für ein Prüfkonzept für den Nachweis einer Nutzungsdauer von mehr als 10 Jahren abgeleitet. Das Prüfkonzept besteht dabei aus einem Katalog von Möglichkeiten, die aktuellen Zulassungsprüfungen auf europäischer Ebene für eine Nutzungsdauer von 10 Jahren auf einen längeren Zeitraum zu erweitern.
N2 - Within the scope of the research project IGF 20470N, investigations were carried out on the assessment of the aging behavior of intumescent coatings (ICs) for the fire protection of steel members. With the help of the results of an extensive literature research as well as experimental and numerical investigations, a proposal for a test concept for the proof of a service life of ICs of more than 10 years was to be derived on the basis of short-term tests. The evaluation of the aging behavior of ICs presupposes that the aging mechanisms are sufficiently known.
For this purpose, data from short- and long-term tests of national approval tests of the last decades were first systematically evaluated. Subsequently, extensive experimental investigations were carried out on a water-based and epoxy resin-based model formulation. Since it is known from the literature that the effects of weathering may lead to a change in the concentrations of the constituents within the coating, investigations were carried out with formulations of the ICs in which individual constituents were systematically reduced. In addition to optical investigations, thermoanalytical methods (DSC-TG-, ATR-FTIR-, elemental-, color analysis) were used and fire tests were carried out on coated steel plates. Furthermore, the model formulations were subjected to the accelerated short-term tests of EAD 350402-00-1106 (2017), which regulates the approval of products at the European level. For the water-based model formulation, the weathering for the interior application with a high moisture content (type Z1) was repeated several times (1x, 3x, 6x). For the epoxy resin-based model formulation, the weathering corresponded to the cycle for exterior application (type X). Fire tests as well as thermoanalytical and optical investigations were carried out to analyze the aging behavior and the thermal protection performance.
Subsequently, numerical simulations of steel members with aged ICs were carried out and validated on the basis of the experimental investigations. With the help of the numerical models, an evaluation of the thermal protection performance of steel members with aged ICs can be carried out.
Bases on the findings, a proposal for a test concept for the verification of a service life of more than 10 years was derived. The test concept consists of a catalogue of possibilities for extending the current approval tests at European level for a service life of 10 years to a longer period.
KW - Brandschutz
KW - Dauerhaftigkeit
KW - Alterung
KW - Reaktive Brandschutzsysteme
KW - Brandversuche
PY - 2022
UR - https://dast.deutscherstahlbau.de/veroeffentlichungen/forschungsberichte
SP - 1
EP - 367
PB - Stahlbau Verlags- und Service GmbH
CY - Düsseldorf
AN - OPUS4-57257
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marti, J.
A1 - Schartel, Bernhard
A1 - Oñate, E.
T1 - Simulation of the burning and dripping cables in fire using the particle finite element method
N2 - The behavior of the cable jacket in fire characterized by the tendency to melt and drip constitutes a major source of fire hazard. The reason is that the melted material may convey the flame from one point to another, expanding fire and contributing to the fire load. In this article, the capability of a new computational strategy based on the particle finite element method for simulating a bench-scale cables burning test is analyzed. The use bench-scale test has been previously used to simulate the full-scale test described in EN 50399. As the air effect is neglected, a simple combustion model is included. The samples selected are two cables consisting of a copper core and differently flame retarded thermoplastic polyurethane sheets. The key modeling parameters were determined from different literature sources as well as experimentally. During the experiment, the specimen was burned under the test set-up condition recording the process and measuring the temperature evolution by means of three thermocouples. Next, the test was reproduced numerically and compared with a real fire test. The numerical results show that the particle finite element method can accurately predict the evolution of the temperature and the melting of the jacket.
KW - Dripping behavior
KW - Particle finite element method
KW - Cables in fire
KW - Fire behavior
KW - Fire simulation
KW - Cable bundle
PY - 2022
DO - https://doi.org/10.1177/07349041211039752
SN - 0734-9041
VL - 40
IS - 1
SP - 3
EP - 25
PB - Sage
AN - OPUS4-54185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gupta, P.
A1 - Karnaushenko, D. D.
A1 - Becker, C.
A1 - Okur, I. E.
A1 - Melzer, Michael
A1 - Özer, B.
A1 - Schmidt, O. G.
A1 - Karnaushenko, D.
T1 - Large Scale Exchange Coupled Metallic Multilayers by Roll-to-Roll (R2R) Process for Advanced Printed Magnetoelectronics
N2 - Till now application of printed magnetoelectronics is hindered by lack of large area exchange coupled metallic multilayers required to produce printable magneto-sensory inks. Large-scale roll-to-roll (R2R) fabrication process is an attractive approach owing to its capabilities for high volume, high throughput, and large area manufacturing. Precise and high performance R2R sputtering technology is developed to fabricate large area giant magnetoresistive (GMR) thin-films stacks that contain 30 metallic bilayers prepared by continuous R2R sputtering of Co and Cu sequential on a hundred meters long polyethylene terephthalate (PET) web. The R2R sputtered Co/Cu multilayer on a 0.2 × 100 m2 PET web exhibits a GMR ratio of ≈40% achieving the largest area exchange coupled room temperature magneto-sensitive system demonstrated to date. The prepared GMR thin-film is converted to magnetosensitive ink that enables printing of magnetic sensors with high performance in a cost-efficient way, which promotes integration with printed electronics. An average GMR ratio of ≈18% is obtained for 370 printed magnetic sensors. The realized precise R2R sputtering approach can also be extended to a wide range of hybrid thin-film material systems opening up a path for new functional inks applied with printing technologies.
KW - Printed Electronics
KW - Flexible Magnetic Sensors
KW - Roll-to-Roll Processing
KW - Functional Materials
KW - Upscaling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552344
DO - https://doi.org/10.1002/admt.202200190
SN - 2365-709X
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim, Deutschland
AN - OPUS4-55234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frunza, L.
A1 - Zgura, I
A1 - Ganea, C. P.
A1 - Schönhals, Andreas
T1 - Molecular dynamics of alkyl benzoate liquid crystals in the bulk state and in the surface layer of their composites with oxide nanopowders
N2 - This paper presents the results concerning monotropic nematic liquid crystals 4-pentylphenyl 40-alkyl benzoate (5PnB) (n = 3 or 5 carbon atoms in the alkyl chain). Their mesophase properties were supported by images of the polarized optical microscopy. Molecular dynamics in the bulk samples or in the composites prepared with aerosil A380 was investigated by broadband dielectric spectroscopy in a large temperature range, appropriately chosen. Thermo gravimetric and infrared investigations were additionally performed. The data were compared with those of structurally related nematics like cyanophenyl pentyl benzoates, which have a cyan group instead of the pentyl chain. The dielectric spectra of the bulk 3P5B and 5P5B demonstrate a dielectric behavior with several relaxation processes as expected for nematic liquid crystals. The temperature dependence of the relaxation rates (and of the dielectric strength) seems to have two distinguished regimes. Thus, in the isotropic state, at higher temperatures the data obey the Vogel–Fulcher–Tammann law, whereas an Arrhenius law is fitted at lower temperature, in a close similarity to the behavior of a constrained dynamic glass transition. Samples with a high density of silica (larger than 7 g aerosil/1 g of 5PnB) were prepared to observe a thin layer adsorbed on the particle surface; it was estimated that almost each guest 5PnB molecule interacts with the aerosil surface. For the composites only one main relaxation process is observed at frequencies much lower than those for the corresponding bulk, which was assigned to the dynamics of the molecules in the surface layer. Infrared spectroscopy shows that these molecules interact with the surface by the ester carbonyl group leading to the monolayer self-assembly at liquid–solid interface. We note once more the importance of the functional unit(s) for the interaction with the hydroxyl groups on the aerosil surface.
KW - Liquid crystals
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119374
SN - 0167-7322
VL - 359
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-54867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghazanfari, M. R.
A1 - Vittadello, L.
A1 - Al-Sabbagh, Dominik
A1 - Santhosh, A.
A1 - Frankcom, C.
A1 - Fuß, F.
A1 - von Randow, C. A.
A1 - Siemensmeyer, K.
A1 - Vrijmoed, J. C.
A1 - Emmerling, Franziska
A1 - Jerabek, P.
A1 - Irmlau, M.
A1 - Thiele, G.
T1 - Remarkable Infrared Nonlinear Optical, Dielectric, and Strong Diamagnetic Characteristics of Semiconducting K3[BiS3]
N2 - The ternary sulfido bismuthate K3[BiS3] is synthesized in quantitative yields. The material exhibits nonlinear optical properties with strong second harmonic generation properties at arbitrary wavelengths in the infrared spectral range and a notable laser-induced damage threshold of 5.22 GW cm−2 for pulsed laser radiation at a wavelength of 1040 nm, a pulse duration of 180 fs, and a repetition rate of 12.5 kHz. K3[BiS3] indicates semiconductivity with a direct optical band gap of 2.51 eV. Dielectric and impedance characterizations demonstrate κ values in the range of 6−13 at 1 kHz and a high electrical resistivity. A strong diamagnetic behavior with a susceptibility of −2.73 × 10−4 m3 kg−1 at room temperature is observed. These results suggest it is a promising nonlinear optical candidate for the infrared
region. The synergic physical characteristics of K3[BiS3] provide insight into the correlation of optical, electrical, and magnetic properties.
KW - Electrical properties
KW - Insulators
KW - Materials
KW - Nonlinear optics
KW - Quantum mechanics
PY - 2022
DO - https://doi.org/10.1021/acs.jpclett.2c01689
VL - 13
IS - 30
SP - 6987
EP - 6993
PB - ACS Publications
AN - OPUS4-55456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Roed, L.
A1 - Mehri, S.
A1 - Ingebrigtsen, T.
A1 - Hecksher, T.
A1 - Dyre, J.
A1 - Niss, K.
T1 - Predicting nonlinear physical aging of glasses from equilibrium relaxation via the material time
N2 - The noncrystalline glassy state of matter plays a role in virtually all fields of materials science and offers complementary properties to those of the crystalline counterpart. The caveat of the glassy state is that it is out of equilibrium and therefore exhibits physical aging, i.e., material properties change over time. For half a century, the physical aging of glasses has been known to be described well by the material-time concept, although the existence of a material time has never been directly validated. We do this here by successfully predicting the aging of the molecular glass 4-vinyl-1,3-dioxolan-2-one from its linear relaxation behavior. This establishes the defining property of the material time. Via the fluctuation-dissipation theorem, our results imply that physical aging can be predicted from thermal-equilibrium fluctuation data, which is confirmed by computer simulations of a binary liquid mixture.
KW - Physical aging
KW - Equilibrium relaxation
KW - Glass
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546015
DO - https://doi.org/10.1126/sciadv.abl9809
SN - 2375-2548
VL - 8
IS - 11
SP - 1
EP - 8
PB - American Association for the Advancement of Science
CY - Washington, DC
AN - OPUS4-54601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pakrashy, S.
A1 - Mandal, P. K.
A1 - Goswami, J. N.
A1 - Dey, S. K.
A1 - Choudhury, S. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Alasmary, F. A.
A1 - Dolai, M.
T1 - Bioinformatics and Network Pharmacology of the First Crystal Structured Clerodin: Anticancer and Antioxidant Potential against Human Breast Carcinoma Cell
N2 - Clerodin was isolated from the medicinal plant Clerodendrum infortunatum, and CSD search showed the first crystal structure of clerodin by a single-crystal X-ray diffraction study. We checked its binding potential with target proteins by docking and conducted network pharmacology analysis, ADMET analysis, in silico pathway analysis, normal mode analysis (NMA), and cytotoxic activity studies to evaluate clerodin as a potential anticancer agent. The cell viability studies of clerodin on the human breast carcinoma cell line (MCF-7) showed toxicity on MCF-7 cells but no toxicity toward normal human lymphocyte cells (HLCs). The anticancer mechanism of clerodin was validated by its enhanced capacity to produce intracellular reactive oxygen species (ROS) and to lower the reduced glutathione content in MCF-7 cells.
KW - Anticancer
KW - Clerodin
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567600
DO - https://doi.org/10.1021/acsomega.2c07173
SN - 2470-1343
VL - 7
IS - 51
SP - 48572
EP - 48582
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, R.
A1 - Fa, X.
A1 - Yang, J.
A1 - Cheng, Z.
A1 - Ansari, A. A.
A1 - Ou, Jun
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Preparation of core–shell structured NaYF4:Yb3+/ Tm3+@NaYF4:Yb3+/Er3+ nanoparticles with high sensitivity, low resolution and good reliability and application of their fluorescence temperature properties
N2 - A series of NaYF4:Yb3+/Tm3+@NaYF4:Yb3+/Er3+ nanoparticles doped with Tm3+ and Er3+ were successfully prepared by the solvothermal method. Under 980 nm laser excitation, intense upconversion emission peaks of Tm3+ and Er3+ were observed for all samples. By doping Tm3+ and Er3+ with core–shell partitioning, not only a significant increase in fluorescence intensity could be achieved, but also simultaneous temperature measurements on multiple thermocouple energy levels could be realised. In addition, the temperature sensing performance of different thermocouple energy levels was also investigated, and it was found that the 3 F3 → 3 H6 and 1 G4 → 3 F4 thermocouple energy level pairs of Tm3+ were the best, with maximum absolute sensitivity and maximum relative sensitivity of up to 0.0250 K−1 and 2.155% K−1 respectively, higher than the sensitivity of other thermocouple energy levels. It has a temperature resolution of less than 0.0139 K, which is lower than that of most materials available today. By using this material as a probe to build a fiber optic temperature sensor platform, it was found to have reliable temperature measurement performance.
KW - Flourescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Temperature
KW - Nano
KW - Particle
KW - Upconversion
KW - Lanthanide
KW - Qantum yield
KW - Quality assurance
KW - Monitoring
KW - Infrastructure
PY - 2022
DO - https://doi.org/10.1039/d1ce01729b
VL - 24
IS - 9
SP - 1752
EP - 1763
PB - RSC Publishing
AN - OPUS4-54416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Grengg, C.
A1 - Ukrainczyk, N.
A1 - Mittermayr, F.
A1 - Dietzel, M.
T1 - Acid resistance of alkali-activated materials: Recent advances and research needs
N2 - Cementitious materials are frequently applied in environments in which they are exposed to acid attack, e.g., in sewer systems, biogas plants, and agricultural/food-related industries. Alkali-activated materials (AAMs) have repeatedly been shown to exhibit a remarkably high resistance against attack by organic and inorganic acids and, thus, are promising candidates for the construction and the repair of acid-exposed structures. However, the reaction mechanisms and processes affecting the acid resistance of AAMs have just recently begun to be understood in more detail. The present contribution synthesises these advances and outlines potentially fruitful avenues of research. The interaction between AAMs and acids proceeds in a multistep process wherein different aspects of deterioration extend to different depths, complicating the overall determination of acid resistance. Partly due to this indistinct definition of the ‘depth of corrosion’, the effects of the composition of AAMs on their acid resistance cannot be unambiguously identified to date. Important parallels exist between the deterioration of low-Ca AAMs and the weathering/corrosion of minerals and glasses (dissolution-reprecipitation mechanism). Additional research requirements relate to the deterioration mechanism of high-Ca AAMs; how the character of the corroded layer influences the rate of deterioration; the effects of shrinkage and the bond between AAMs and substrates.
KW - Alkali-activated materials
KW - Acid attack
KW - Acid resistance
KW - Concrete repair
KW - MIC
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557376
DO - https://doi.org/10.21809/rilemtechlett.2022.157
SN - 2518-0231
VL - 7
SP - 58
EP - 67
PB - RILEM Publications SARL
CY - Paris
AN - OPUS4-55737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Hodoroaba, Vasile-Dan
A1 - Kraehnert, R.
A1 - Hertwig, Andreas
T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films
N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing.
We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP).
KW - Electrochemical catalysts
KW - Mixed metal oxide
KW - Multi-sample analysis
KW - Spectroscopic ellipsometry
KW - Thin mesoporous films
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026
DO - https://doi.org/10.1515/aot-2022-0007
SN - 2192-8584
SN - 2192-8576
VL - 11
IS - 3-4 (Topical issue: Ellipsometry)
SP - 137
EP - 147
PB - De Gruyter
CY - Berlin
AN - OPUS4-55102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, K.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Chemical and thixotropic contribution to the structural build-up of cementitious materials
N2 - The structural build-up of fresh cement paste is often considered as a purely thixotropic phenomenon in literature even though cementitious materials undergo a non-reversible hydration process that can have an influence on the structuration process. In the current paper a method is proposed to validate the impact of the non-reversible structural build-up. It is shown that fresh cement paste samples lose their structural gain almost completely due to thixotropy while the structural build-up due to hydration can be observed but occurs in a significantly lower order of magnitude over the course of the first hours of hydration. In addition, it is shown, that the chemical component of the structural build-up accelerates with the onset of the acceleration period of hydration, while its contribution in the entire structural build-up remains constant.
KW - Thixotropy
KW - Structural build-up
KW - Penetration test
KW - Rheological properties
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.128307
SN - 0950-0618
VL - 345
IS - 128307
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-58248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bodechtel, S.
A1 - Fuhrmann, A.
A1 - Henning, A.
A1 - Hahn, Oliver
A1 - Rabin, Ira
A1 - Kreische, W.
A1 - Mäder, M.
T1 - The Madonna with the Wash-Basin by Giulio Romano: A Multidisciplinary Study of the Painting’s History
N2 - In an interdisciplinary collaboration, restorers, art historians, and scientists examined Guilio Romano’s The Madonna with the Wash-Basin of 1525 (Dresden State Art Collections). Insights into the painting technique along with art historical comparisons provided the opportunity for a better understanding of the painting’s genesis, in particular concerning an early reworking of the background by the artist. A recovery and reconstruction of the earlier version of the background is now possible. The discovery of zinc in distinct passages of the painting, as well as the grey-black pigment stibnite and glass particles used as a supplement in paint layers are of special interest. The technological investigation initiated a discussion about the circumstances of the revision, as well as the painting’s relation to Vasari’s Lives of Artists.
KW - Giulio Romano
KW - Holy Family
KW - Basin
KW - Reworking
KW - Pentimenti
KW - Portrayal of St Joseph
KW - Sixteenth-century painting technique
KW - Raphael school
KW - Zinc
KW - Antimony black (stibnite)
KW - Vasari
PY - 2022
DO - https://doi.org/10.1080/00393630.2022.2118302
VL - 2022
SP - 2
EP - 12
PB - Routledge Taylor & Francis Group
CY - London, UK
AN - OPUS4-55970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernges, T.
A1 - Hanus, R.
A1 - Wankmiller, B.
A1 - Imasato, K.
A1 - Lin, S.
A1 - Ghidiu, M.
A1 - Gerlitz, M.
A1 - Peterlechner, M.
A1 - Graham, S.
A1 - Hautier, G.
A1 - Pei, Y.
A1 - Hansen, M. R.
A1 - Wilde, G.
A1 - Snyder, G. J.
A1 - George, Janine
A1 - Agne, M T.
A1 - Zeier, W. G.
T1 - Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity
N2 - Next-generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two-channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non-propagating diffuson-like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson-mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson-mediated transport. Bridging the fields of solid-state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so-called Meyer-Neldel behavior in ionic conductors to phonon occupations.
KW - Diffusons
KW - DFT
KW - Phonons
KW - Thermoelectrics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547140
DO - https://doi.org/10.1002/aenm.202200717
SN - 1614-6832
VL - 12
IS - 22
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-54714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sternbaek, L.
A1 - Kimani, Martha Wamaitha
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Janicke, B.
A1 - Alm, K.
A1 - Gjörloff-Wingren, A.
A1 - Eriksson, H.
T1 - Molecularly Imprinted Polymers Exhibit Low Cytotoxic and Inflammatory Properties in Macrophages In Vitro
N2 - Molecularly imprinted polymers (MIPs) against sialic acid (SA) have been developed as a detection tool to target cancer cells. Before proceeding to in vivo studies, a better knowledge of the overall effects of MIPs on the innate immune system is needed. The aim of this study thus was to exemplarily assess whether SA-MIPs lead to inflammatory and/or cytotoxic responses when administered to phagocytosing cells in the innate immune system. The response of monocytic/macrophage cell lines to two different reference particles, Alhydrogel and PLGA, was compared to their response to SA-MIPs. In vitro culture showed a cellular association of SA-MIPs and Alhydrogel, as analyzed by flow cytometry. The reference particle Alhydrogel induced secretion of IL-1b from the monocytic cell line THP-1, whereas almost no secretion was provoked for SA-MIPs. A reduced number of both THP-1 and RAW 264.7 cells were observed after incubation with SA-MIPs and this was not caused by cytotoxicity. Digital holographic cytometry showed that SA-MIP treatment affected cell division, with
much fewer cells dividing. Thus, the reduced number of cells after SA-MIP treatment was not linked to SA-MIPs cytotoxicity. In conclusion, SA-MIPs have a low degree of inflammatory properties, are not cytotoxic, and can be applicable for future in vivo studies.
KW - Molecularly imprinted polymers
KW - Digital holographic cytometry
KW - Cytotoxicity
KW - Proinflammatory cytokines
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552250
DO - https://doi.org/10.3390/app12126091
SN - 2076-3417
VL - 12
IS - 12
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ziesche, R.F.
A1 - Hack, J.
A1 - Rasha, L.
A1 - Maier, M.
A1 - Tan, C.
A1 - Heenan, T.M.M.
A1 - Markötter, Henning
A1 - Kardjilov, N.
A1 - Manke, I.
A1 - Kockelmann, W.
A1 - Brett, D.J.L.
A1 - Shearing, P.R.
T1 - High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells
N2 - In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings.
This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs.
KW - Neutron imaging
KW - Tomography
KW - Polymer electrolyte membrane fuel cell
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545978
DO - https://doi.org/10.1038/s41467-022-29313-5
VL - 13
IS - 1
SP - 1616
PB - Nature Publishing Group UK
CY - London
AN - OPUS4-54597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Van Tran, K.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561649
DO - https://doi.org/10.1016/j.matdes.2022.111037
SN - 0264-1275
VL - 222
SP - 111037
PB - Elsevier Ltd.
AN - OPUS4-56164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, K. V.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569101
DO - https://doi.org/10.1016/j.matdes.2022.111037
VL - 222
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-56910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tengattini, A
A1 - Kardjilov, N
A1 - Helfen, L
A1 - Douissard, P A
A1 - Lenoir, N
A1 - Markötter, Henning
A1 - Hilger, A
A1 - Arlt, T
A1 - Paulisch, M
A1 - Turek, T
A1 - Manke, Ingo
T1 - Compact and versatile neutron imaging detector with sub-4μm spatial resolution based on a single-crystal thin-film scintillator
N2 - A large and increasing number of scientific domains pushes for high neutron imaging resolution achieved in reasonable times. Here we present the principle, design and performance of a detector based on infinity corrected optics combined with a crystalline Gd3Ga5O12 : Eu scintillator, which provides an isotropic sub-4 μm true resolution. The exposure times are only of a few minutes per image. This is made possible also by the uniquely intense cold neutron flux available at the imaging beamline NeXT-Grenoble. These comparatively rapid acquisitions are compatible with multiple high quality tomographic acquisitions, opening new venues for in-operando testing, as briefly exemplified here.
KW - Neutron imaging
KW - Scintillator
KW - Resolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549836
DO - https://doi.org/10.1364/oe.448932
VL - 30
IS - 9
SP - 14461
EP - 14477
PB - Optica
CY - Washington, DC
AN - OPUS4-54983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Roveda, Ilaria
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Synchrotron X-ray refraction detects microstructure and porosity evolution during in-situ heat treatments
N2 - For the first time, synchrotron X-ray refraction radiography (SXRR) has been paired with in-situ heat treatment to monitor microstructure and porosity evolution as a function of temperature. The investigated material was a laser powder bed fusion (LPBF) manufactured AlSi10Mg, where the initial eutectic Si network is known to disintegrate and spherodize into larger particles with increasing temperature. Such alloy is also prone to thermally induced porosity (TIP). We show that SXRR allows detecting the changes in the Si-phase morphology upon heating, while this is currently possible only using scanning electron microscopy. SXRR also allows observing the growth of pores, usually studied via X-ray computed tomography, but on much smaller fields-of-view. Our results show the great potential of in-situ SXRR as a tool to gain in-depth knowledge of the susceptibility of any material to thermally induced damage and/or microstructure evolution over statistically relevant volumes.
KW - Synchrotron X-ray refraction radiography
KW - Si network disintegration
KW - Thermally induced porosity (TIP)
KW - Laser powder bed fusion (LPBF)
KW - Statistically relevant volumes
KW - AlSi10Mg alloy
PY - 2022
DO - https://doi.org/10.1016/j.msea.2022.142732
SN - 0921-5093
VL - 838
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
T1 - Systematic ranking of filaments regarding their particulate emissions during fused filament fabrication 3D printing by means of a proposed standard test method
N2 - The diversity of fused filament fabrication (FFF) filaments continues to grow rapidly as the popularity of FFF-3D desktop printers for the use as home fabrication devices has been greatly increased in the past decade. Potential harmful emissions and associated health risks when operating indoors have induced many emission studies. However, the lack of standardization of measurements impeded an objectifiable comparison of research findings. Therefore, we designed a chamber-based standard method, i.e., the strand printing method (SPM), which provides a standardized printing procedure and quantifies systematically the particle emission released from individual FFF-3D filaments under controlled conditions. Forty-four marketable filament products were tested. The total number of emitted particles (TP) varied by approximately four orders of magnitude (1E9 ≤ TP ≤ 1E13), indicating that origin of polymers, manufacturer-specific additives, and undeclared impurities have a strong influence. Our results suggest that TP characterizes an individual filament product and particle emissions cannot be categorized by the polymer type (e.g., PLA or ABS) alone. The user's choice of a filament product is therefore decisive for the exposure to released particles during operation. Thus, choosing a filament product awarded for low emissions seems to be an easily achievable preemptive measure to prevent health hazards.
KW - Emission test method
KW - FFF-printing
KW - Particle emission
KW - Indoor air quality
KW - FFF-filament
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545087
DO - https://doi.org/https://doi.org/10.1111/ina.13010
SN - 1600-0668
VL - 32
IS - 3
SP - 1
EP - 12
PB - Wiley
CY - Hoboken, New Jersey, USA
AN - OPUS4-54508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n = 5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations probing the molecular mobility, a c-relaxation due to localized fluctuations as well as two glassy dynamics, the acore- and aalkyl-relaxation, were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n = 8 from a rigid constrained (n = 5,6) to a softer system (n = 10,12) was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene-like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition.
KW - Discotic liquid crystals
KW - Broadband dielectric spectroscopy
KW - Advanced calorimetry
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119212
VL - 358
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-54721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fürst, Richard
A1 - Hejtmanek, P.
A1 - Vlach, T.
A1 - Repka, J.
A1 - Mozer, V.
A1 - Hajek, P.
T1 - Experimental Evaluation of Carbon Reinforced TRC with Cement Suspension Matrix at Elevated Temperature
N2 - Textile-reinforced concrete (TRC) is a new composite material comprising high-performance concrete and textile reinforcement from textile yarns with a matrix, usually consisting of epoxy resins (ER). The most significant advantage of ER is the homogenization of all filaments in the yarn and full utilization of its tensile potential. Nevertheless, ER matrix is a critical part of TRC design from the perspective of the fire resistance due to its relatively low resistance at temperatures of approximately 120 C. This work expands the previously performed mechanical tests at normal temperatures with cement suspension (CS) as a non-combustible material for the yarn matrix. Here, the mechanical properties of CS matrix at elevated temperatures were verified. It was found that the addition of polypropylene fibers into HPC negatively affected the mechanical results of CS matrix specimens. Simultaneously, thermal insulation effect of the covering layers with different thicknesses did not significantly influence the residual bending strength of specimens with CS matrix and achieved similar results as reference specimens. Furthermore, all specimens with ER matrix progressively collapsed. Finally, CS as a textile reinforcement of yarn matrix appears to be a suitable solution for increasing the temperature resistance of TRC structures and for substituting synthetic resins.
KW - Cement matrix
KW - Cement suspension
KW - Carbon fibers
KW - Textile reinforced concrete
KW - High-performance concrete
KW - Elevated temperature
KW - Fire safety
KW - Fire resistance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550766
DO - https://doi.org/10.3390/polym14112174
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Kaufmann, Jan Ole
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Brangsch, J.
A1 - Adams, L. C.
A1 - Zhao, J.
A1 - Reimann, C.
A1 - Saatz, Jessica
A1 - Traub, Heike
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Iron Oxide Nanoparticles for Visualization of Prostate Cancer in MRI
N2 - Prostate cancer (PCa) is one of the most common cancers in men. For detection and diagnosis of PCa, non-invasive methods, including magnetic resonance imaging (MRI), can reduce the risk potential of surgical intervention. To explore the molecular characteristics of the tumor, we investigated the applicability of ferumoxytol in PCa in a xenograft mouse model in two different tumor volumes, 500 mm3 and 1000 mm3. Macrophages play a key role in tumor progression, and they are able to internalize iron-oxide particles, such as ferumoxytol. When evaluating T2*-weighted sequences on MRI, a significant decrease of signal intensity between pre- and post-contrast images for each tumor volume (n = 14; p < 0.001) was measured. We, furthermore, observed a higher signal loss for a tumor volume of 500 mm3 than for 1000 mm3. These findings were confirmed by histological examinations and laser ablation inductively coupled plasma-mass spectrometry. The 500 mm3 tumors had 1.5% iron content (n = 14; sigma = 1.1), while the 1000 mm3 tumors contained only 0.4% iron (n = 14; sigma = 0.2). In vivo MRI data demonstrated a correlation with the ex vivo data (R2 = 0.75). The results of elemental analysis by inductively coupled plasma-mass spectrometry correlated strongly with the MRI data (R2 = 0.83) (n = 4). Due to its long retention time in the blood, biodegradability, and low toxicity to patients, ferumoxytol has great potential as a contrast agent for visualization PCa.
KW - Imaging
KW - Nanoparticle
KW - Cancer
KW - Iron oxide
KW - ICP-MS
KW - Magnetic resonance imaging
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550075
DO - https://doi.org/10.3390/cancers14122909
VL - 14
IS - 12
SP - 1
EP - 13
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Time-Resolved InSitu Monitoring of Mechanochemical Reactions
N2 - Mechanochemical transformations offer environmentally benign synthesis routes, whilst enhancing both the speed and selec-tivity of reactions. In this light, mechanochemistry promises to trans-form the way in which chemistry is done in both academia and indus-try but is greatly hindered by a current lack in mechanistic understand-ing. The continued development and use of time-resolved in situ(TRIS) approaches to monitor mechanochemical reactions provides a new dimension to elucidatethese fascinating transformations. We here discuss recent trends in method development that have pushed the boundaries of mechanochemical research. New features of mech-anochemical reactions obtained by TRIS techniques are subse-quently discussed, shedding light on how different TRISapproaches have beenused. Emphasis is placed on the strength of combining complementary techniques. Finally, we outline our views for the po-tential of TRIS methods in mechanochemical research, towards es-tablishing a new, environmentally benign paradigm in the chemical sciences
KW - Mechanochemistry
KW - Material synthesis
KW - Green chemistry
PY - 2022
DO - https://doi.org/10.1002/anie.202117270
SN - 1433-7851
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezhov, Alexander
A1 - Ben Shir, I.
A1 - Schmidt, A.
A1 - Kovler, K.
A1 - Diesendruck, Ch. E.
T1 - Retardation mechanism of cement hydration by a comb polyphosphate superplasticizer
N2 - The retardation mechanism of cement hydration as imparted by the addition of polyphosphate comb superplasticizer to model cement containing C3S, C3A and calcium sulfate hemihydrate is studied using XRD, ss NMR and calorimetry. Our findings show the retardation effect caused by the direct addition of polyphosphate comb superplasticizer differs significantly to that of conventional polycarboxylate superplasticizers. Conversely to polycarboxylates, polyphosphates, at a low dosage, inhibits the silicate reaction without affecting the aluminate reaction and formation of ettringite. Yet, at high doses, both reactions are hampered, and the induction period extended, followed by accelerated aluminate and silicate reactions.
KW - Superplasticizer
KW - Polyphosphate
KW - Retardation
KW - Cement hydration
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.128698
SN - 0950-0618
VL - 352
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-58246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Z.
A1 - Dong, K.
A1 - Mazzio, K. A.
A1 - Hilger, A.
A1 - Markötter, Henning
A1 - Wilde, F.
A1 - Heinemann, T.
A1 - Manke, I.
A1 - Adelhelm, P.
T1 - Phase transformation and microstructural evolution of CuS electrodes in solid-state batteries probed by in situ 3D X-ray tomography
N2 - Copper sulfide shows some unique physico-chemical properties that make it appealing as a cathode active material (CAM) for solid-state batteries (SSBs). The most peculiar feature of the electrode reaction is the reversible formation of μm-sized Cu crystals during cycling, despite its large theoretical volume change (75%). Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X-ray tomography. The formation of μm-sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z-oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z-oriented reversible displacement of the cathode
pellet, which is linked to the plating/stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft materials.
KW - Copper sulfide
KW - Crack evolution
KW - Digital volume correlation
KW - Phase transformation
KW - Solid-state batteries
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564577
DO - https://doi.org/10.1002/aenm.202203143
IS - 2203143
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-56457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fischer, Janina
T1 - Suspensionsarray-Fluoreszenzimmunoassay zur Multiplexbestimmung von SARS-CoV-2-Antikörpern
N2 - Übergeordnetes Ziel der Arbeit war die Entwicklung und Optimierung eines Suspensionsarray-Fluoreszenzimmunoassays (SAFIA) für die simultane Bestimmung verschiedener gegen SARS-CoV-2-Proteine gerichtete Antikörper mittels Multiplexdetektion in komplexen Matrices wie humanen Blutserumproben.
KW - SARS-CoV-2
KW - Corona
KW - COVID-19
KW - Coronavirus
KW - Virus
KW - Spike-Protein
KW - Nucleocapsid-Protein
KW - RBD
KW - SAFIA
KW - LFIA
KW - ELISA
KW - Partikel
KW - Mutationen
KW - Neutralisierende Antikörper
KW - Durchflusszytometrie
KW - ACE2
PY - 2022
SP - 1
EP - 99
PB - Humboldt-Universität zu Berlin
CY - Berlin
AN - OPUS4-54722
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haapalehto, Matias
A1 - Pinomaa, Tatu
A1 - Wang, Lei
A1 - Laukkanen, Anssi
T1 - An atomistic simulation study of rapid solidification kinetics and crystal defects in dilute Al–Cu alloys
N2 - Rapid solidification kinetics of dilute Al–Cu alloys is simulated using a quantum mechanics based bondorder potential (BOP), in free solidification conditions, to determine kinetic and thermodynamic properties of solidification, as well as point defects and chemical ordering of the solidified structures. We measure the anisotropic kinetic coefficient, anisotropic solid–liquid interface energy, as well as solute trapping kinetics in terms of partition coefficient versus velocity and solute drag coefficient. Furthermore, solid–liquid interface free energy and its anisotropy are measured in equilibrium simulations, showing reasonably good agreement with previous studies. We also verified the self-consistency of the MD simulations, by comparing the interfacial temperature vs. velocity to that predicted by the continuous growth model. These solid–liquid interface properties are important for quantitative parametrization of larger scale solidification modeling techniques such as phase field models. We also investigated the point defect content, local chemical ordering, and local crystalline structures in the rapidly solidified samples. We found clustering of solute with vacancies, whereas copper atoms repelled each other in these dilute alloy simulations. In addition to vacancies, a large number of interstitials were found. In solidification velocities approaching the complete solute trapping regime, we found that the vacancies and interstitials formed in conjunction, i.e. as Frenkel pairs. Finally, in addition to FCC, we detected BCC and HCP phases, where the latter two were accompanied by an increase in local copper content. Understanding the formation of point defects and their relationship to chemical ordering is an important step towards controlling the formation of pre-precipitates and precipitates, which are an important strengthening mechanism for aluminum–copper alloys.
KW - Rapid solidification
KW - Aluminum–copper
KW - MD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628722
DO - https://doi.org/10.1016/j.commatsci.2022.111356
SN - 0927-0256
VL - 209
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Wei, Y.
A1 - Kühbach, M.
A1 - Zhao, H.
A1 - Vogel, F.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
A1 - Raabe, D.
A1 - Gault, B.
T1 - Revealing in-plane grain boundary composition features through machine learning from atom probe tomography data
N2 - Grain boundaries (GBs) are planar lattice defects that govern the properties of many types of polycrystalline materials. Hence, their structures have been investigated in great detail. However, much less is known about their chemical features, owing to the experimental difficulties to probe these features at the atomic length scale inside bulk material specimens. Atom probe tomography (APT) is a tool capable of accomplishing this task, with an ability to quantify chemical characteristics at near-atomic scale. Using APT data sets, we present here a machine-learning-based approach for the automated quantification of chemical features of GBs. We trained a convolutional neural network (CNN) using twenty thousand synthesized images of grain interiors, GBs, or triple junctions. Such a trained CNN automatically detects the locations of GBs from APT data. Those GBs are then subjected to compositional mapping and analysis, including revealing their in-plane chemical decoration patterns. We applied this approach to experimentally obtained APT data sets pertaining to three case studies, namely, Ni-P, Pt-Au, and Al-Zn-Mg-Cu alloys. In the first case, we extracted GB specific segregation features as a function of misorientation and coincidence site lattice character. Secondly, we revealed interfacial excesses and in-plane chemical features that could not have been found by standard compositional analyses. Lastly, we tracked the temporal evolution of chemical decoration from early-stage solute GB segregation in the dilute limit to interfacial phase separation, characterized by the evolution of complex composition patterns. This machine-learning-based approach provides quantitative, unbiased, and automated access to GB chemical analyses, serving as an enabling tool for new discoveries related to interface thermodynamics, kinetics, and the associated chemistry-structure-property relations.
KW - Machine learning
KW - Digitalization
KW - Alloy microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543049
DO - https://doi.org/10.1016/j.actamat.2022.117633
SN - 1359-6454
VL - 226
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos Collado, José Antonio
T1 - Experimental volumetric hydrogen uptake determination at 77 K of commercially available metal-organic framework materials
N2 - Storage is still limiting the implementation of hydrogen as an energy carrier to integrate the intermittent operation of renewable energy sources. Among different solutions to the currently used compressed or liquified hydrogen systems, physical adsorption at cryogenic temperature in porous materials is an attractive alternative due to its fast and reversible operation and the resulting reduction in storage pressure. The feasibility of cryoadsorption for hydrogen storage depends mainly on the performance of the used materials for the specific application, where metal-organic frameworks or MOFs are remarkable candidates. In this work, gravimetric and volumetric hydrogen uptakes at 77 K and up to 100 bar of commercially available MOFs were measured since these materials are made from relatively cheap and accessible building blocks. These materials also show relatively high porous properties and are currently near to large-scale production. The measuring device was calibrated at different room temperatures to calculate an average correction factor and standard deviation so that the correction deviation is included in the measurement error for better comparability with different measurements. The influence of measurement conditions was also studied, concluding that the available adsorbing area of material and the occupied volume of the sample are the most critical factors for a reproducible measurement, apart from the samples’ preparation before measurement. Finally, the actual volumetric storage density of the used powders was calculated by directly measuring their volume in the analysis cell, comparing that value with the maximum volumetric uptake considering the measured density of crystals. From this selection of commercial MOFs, the materials HKUST-1, PCN-250(Fe), MOF-177, and MOF-5 show true potential to fulfill a volumetric requirement of 40 g·L−1 on a material basis for hydrogen storage systems without further packing of the powders.
KW - Hydrogen adsorption
KW - Commercial metal-organic frameworks
KW - Hydrogen uptake reproducibility
KW - Volumetric uptake
KW - Packing density
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542215
DO - https://doi.org/10.3390/c8010005
SN - 2311-5629
VL - 8
IS - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-54221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abdallah, Khaled
A1 - Stock, S. C.
A1 - Heeger, Felix
A1 - Koester, M.
A1 - Nájera, F.
A1 - Merino, C.
A1 - Spielvogel, S.
A1 - Gorbushina, Anna
A1 - Kuzyakov, Y.
A1 - Dippold, M. A.
T1 - Nitrogen Gain and Loss Along an Ecosystem Sequence: From Semi-desert to Rainforest
N2 - Plants and microorganisms, besides the climate, drive nitrogen (N) cycling in ecosystems. Our objective was to investigate N losses and N acquisition strategies along a unique ecosystem-sequence (ecosequence) ranging from arid shrubland through Mediterranean woodland to temperate rainforest. These ecosystems differ in mean annual precipitation, mean annual temperate, and vegetation cover, but developed on similar granitoid soil parent material, were addressed using a combination of molecular biology and soil biogeochemical tools. Soil N and carbon (C) contents, δ15N signatures, activities of N acquiring extracellular enzymes as well as the abundance of soil bacteria and fungi, and diazotrophs in bulk topsoil and rhizosphere were determined. Relative fungal abundance in the rhizosphere was higher under woodland and forest than under shrubland. This indicates toward plants' higher C investment into fungi in the Mediterranean and temperate rainforest sites than in the arid site. Fungi are likely to decompose lignified forest litter for efficient recycling of litter-derived N and further nutrients. Rhizosphere—a hotspot for the N fixation—was enriched in diazotrophs (factor 8 to 16 in comparison to bulk topsoil) emphasizing the general importance of root/microbe association in N cycle. These results show that the temperate rainforest is an N acquiring ecosystem, whereas N in the arid shrubland is strongly recycled. Simultaneously, the strongest 15N enrichment with decreasing N content with depth was detected in the Mediterranean woodland, indicating that N mineralization and loss is highest (and likely the fastest) in the woodland across the continental transect. Higher relative aminopeptidase activities in the woodland than in the forest enabled a fast N mineralization. Relative aminopeptidase activities were highest in the arid shrubland. The highest absolute chitinase activities were observed in the forest. This likely demonstrates that (a) plants and microorganisms in the arid shrubland invest largely into mobilization and reutilization of organically bound N by exoenzymes, and (b) that the ecosystem N nutrition shifts from a peptide-based N in the arid shrubland to a peptide- and chitin-based N nutrition in the temperate rainforest, where the high N demand is complemented by intensive N fixation in the rhizosphere.
KW - Nitrogen
KW - Rhizosphere
KW - Microbial abundance
KW - Natural abundance of 15N
KW - Nitrogen fixation
KW - Nitrogen uptake
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543708
DO - https://doi.org/10.3389/fsoil.2022.817641
SN - 2673-8619
VL - 2
SP - 1
EP - 14
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - Optimally rejuvenated model binary glasses
N2 - Using the creation relaxation algorithm developed for the atomistic modeling of the high-dose irradiation limit of crystalline systems, we explore the limits of the structural rejuvenation of a highly excited model binary glass. This high-energy athermal amorphous structure exhibits a direct transition to homogeneous plastic flow and a microstructure that is largely insensitive to this flow, being characterized by a porous system-spanning network of minimally frustrated structural motifs. The observed homogeneous plasticity is mediated by the same string-like structural excitations, which mediate structural relaxation and microplasticity at finite temperature in more relaxed structures. This highly rejuvenated structural asymptote is not far from the structural state of regions, which have experienced athermal shear localization in more relaxed samples, suggesting an optimally rejuvenated glassy structure will always be limited by that produced by shear localization.
KW - Metallic glasses
KW - Creation-relaxation algorithm
KW - Shear
PY - 2022
DO - https://doi.org/10.1103/PhysRevMaterials.6.125604
VL - 6
IS - 12
SP - 1
EP - 13
PB - American Physical Society
AN - OPUS4-56741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimani, Martha Wamaitha
A1 - Kislenko, Evgeniia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents
N2 - In this work, molecular imprinting was combined with direct fluorescence detection of the pesticide Glyphosate (GPS). Firstly, the solubility of highly polar GPS in organic solvents was improved by using lipophilic tetrabutylammonium (TBA+) and tetrahexylammonium (THA+) counterions. Secondly, to achieve fluorescence detection, a fluorescent crosslinker containing urea-binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2–3 nm fluorescent molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles using chloroform as porogen. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA+ counterion was found to be a more powerful phase transfer agent than TBA+ in a biphasic assay, enabling the direct fluorescence detection and quantification of GPS in water. A limit of detection of 1.45 μM and a linear range of 5–55 μM were obtained, which match well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 μM).
KW - Glyphosate
KW - Molecular imprinting
KW - Core-shell particles
KW - Fluorescent sensors
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555281
DO - https://doi.org/10.1038/s41598-022-16825-9
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 15
PB - Macmillan Publishers Limited
CY - London
AN - OPUS4-55528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinmuth-Selzle, K.
A1 - Tchipilov, Teodor
A1 - Backes, A. T.
A1 - Tscheuschner, Georg
A1 - Tang, K.
A1 - Ziegler, K.
A1 - Lucas, K.
A1 - Pöschl, U.
A1 - Fröhlich-Nowoisky, J.
A1 - Weller, Michael G.
T1 - Determination of the protein content of complex samples by aromatic amino acid analysis, liquid chromatography-UV absorbance, and colorimetry
N2 - Fast and accurate determination of the protein content of a sample is an important and non-trivial task of many biochemical, biomedical, food chemical, pharmaceutical, and environmental research activities. Different methods of total protein determination are used for a wide range of proteins with highly variable properties in complex matrices. These methods usually work reasonably well for proteins under controlled conditions, but the results for non-standard and complex samples are often questionable. Here, we compare new and well-established methods, including traditional amino acid analysis (AAA), aromatic amino acid analysis (AAAA) based on the amino acids phenylalanine and tyrosine, reversed-phase liquid chromatography of intact proteins with UV absorbance measurements at 220 and 280 nm (LC-220, LC-280), and colorimetric assays like Coomassie Blue G-250 dye-binding assay (Bradford) and bicinchoninic acid (BCA) assay. We investigated different samples, including proteins with challenging properties, chemical modifications, mixtures, and complex matrices like air particulate matter and pollen extracts. All methods yielded accurate and precise results for the protein and matrix used for calibration. AAA, AAAA with fluorescence detection, and the LC-220 method yielded robust results even under more challenging conditions (variable analytes and matrices). These methods turned out to be well-suited for reliable determination of the protein content in a wide range of samples, such as air particulate matter and pollen.
KW - Air particulate matter
KW - Aromatic amino acid analysis
KW - Atmospheric aerosol
KW - Chemical protein modification
KW - Derivatization
KW - Nitration
KW - Nitrotyrosine
KW - LC-UV absorbance
KW - Pollen extract
KW - Protein quantification
KW - Protein test
KW - Kjeldahl
KW - Tyrosine
KW - Phenylalanine
KW - Hydrolysis
KW - Bradford
KW - BCA test
KW - 280 nm
KW - Air filter samples
KW - Fluorescence
KW - HPLC
KW - Chromatography
KW - Protein content
KW - 150th anniversary of BAM
KW - Topical collection: Analytical Methods and Applications in the Materials and Life Sciences
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545924
UR - https://pubmed.ncbi.nlm.nih.gov/35320366/
DO - https://doi.org/10.1007/s00216-022-03910-1
SP - 1
EP - 14
PB - Springer Nature Limited
CY - New York, Heidelberg
AN - OPUS4-54592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Abrudan, R.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schneider, M.
A1 - Laplanche, G.
A1 - Yusenko, Kirill
T1 - Inner relaxations in equiatomic single-phase high-entropy Cantoralloy
N2 - The superior properties of high-entropy multi-functional materials are strongly connected with their atomic heterogeneity through many different local atomic interactions. The detailed element-specific studies on a local scale can provide insight into the primary arrangements of atoms in multicomponent systems and benefit to unravel the role of individual components in certain macroscopic properties of complex compounds. Herein, multi-edge X-ray absorption spectroscopy combined with reverse Monte Carlo simulations was used to explore a homogeneity of the local crystallographic ordering and specific structure relaxations of each constituent in the equiatomic single-phase facecentered cubic CrMnFeCoNi high-entropy alloy at room temperature. Within the considered fitting approach, all five elements of the alloy were found to be distributed at the nodes of the fcc lattice without any signatures of the additional phases at the atomic scale and exhibit very close statistically averaged interatomic distances (2.54 – 2.55 Å) with their nearest-neighbors. Enlarged structural displacements were found solely for Cr atoms. The macroscopic magnetic properties probed by conventional magnetometry demonstrate no opening of the hysteresis loops at 5 K and illustrate a complex character of the long-range magnetic order after field-assisted cooling in ± 5 T. The observed magnetic behavior is assigned to effects related to structural relaxations of Cr. Besides, the advantages and limitations of the reverse Monte Carlo approach to studies of multicomponent systems like high-entropy alloys are highlighted.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
KW - X-ray absorption near edge structure (XANES)
PY - 2022
DO - https://doi.org/10.1016/j.jallcom.2022.165999
SN - 0925-8388
VL - 920
SP - 1
EP - 31
PB - Elsevier
AN - OPUS4-55457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Fries, S. G.
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Roik, J.
A1 - Agudo Jácome, Leonardo
T1 - The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: Experimental findings and comparison with calculations using the CALPHAD method
N2 - Detailed microstructural characterization of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy in the as-cast state is reported for first time and compared with the state annealed at 1400 oC for 24 h. The former shows a dendritic structure, with a mixture of A2/B2 phases < 20 nm in both the dendritic and interdendritic regions. A mostly amorphous phase, rich in Al and Zr, is found within the interdendritic region. The annealed state reproduced the combination of A2/B2/Al-Zr-rich phases reported previously. Calculations from two relevant ThermoCalc databases were compared with the experimental results. Equilibrium calculations were compared with results for the annealed alloy, whereas solidification paths calculated using Scheil-Gulliver model were used for comparison with the as-cast alloy. A previously hypothesized spinodal decomposition during cooling as the mechanism responsible for the patterned A2/B2 microstructure is confirmed via the CALPHAD calculations, pointing to its use as an efficient design tool for such alloys. Finally, the comparison between the experimental and computational findings allowed better understanding the solidification path and equilibrium stability of this alloy, giving a base to make better decisions on the field of new refractory superalloy design.
KW - CALPHAD database analysis
KW - Refractory superalloys
KW - Chemically complex alloy
KW - Characterization
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545906
DO - https://doi.org/10.1016/j.matdes.2022.110593
SN - 1873-4197
VL - 217
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sestan, A.
A1 - Sreekala, L.
A1 - Markelj, S.
A1 - Kelemen, M.
A1 - Zavasnik, J.
A1 - Liebscher, C.
A1 - Dehm, G.
A1 - Hickel, Tilmann
A1 - Ceh, M.
A1 - Novak, S.
A1 - Jenus, P.
T1 - Non-uniform He bubble formation in W/W2C composite: Experimental and ab-initio study
N2 - Tungsten-tungsten carbide (W/W2C) composites are considered as possible structural materials for future nuclear fusion reactors. Here, we report on the effect of helium (He) implantation on microstructure evolution of polycrystalline W/W2C composite consolidated by field-assisted sintering technique (FAST), homogenously implanted at room temperature with 1 MeV 4He+ ions at the fluence of 8 × 1016 ions cm−2 and annealed at 1873 K for 20 minutes. Samples were analysed by scanning and transmission electron microscopy to study the presence and size of He bubbles. Monomodal He bubbles in W (30-80 nm) are limited to point defects and grain boundaries, with a considerable void denuded zone (150 nm). Bubbles do not form in W2C, but at the W|W2C interface and are considerably larger (200-400 nm). The experimental observations on He behaviour and migration in W and W2C were assessed by density functional theory (DFT) calculations, suggesting He migration and accumulation in the composite are determined by the effective He-He binding in clusters, which will give rise to decohesion. In the presence of He clusters, the decohesion of bulk W into free surfaces is energetically highly favourable but not sufficient in the W2C; hence bubbles are only observed in W grains and interfaces and not within bulk W2C.
KW - Density functional theory
KW - Tungsten
KW - Ditungsten carbide
KW - FAST
KW - Helium implantation
PY - 2022
DO - https://doi.org/10.1016/j.actamat.2021.117608
VL - 226
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-54364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Loges, A.
A1 - Scholz, G.
A1 - de Sousa Amadeu, Nader
A1 - Jingjing, S.
A1 - Emmerling, Franziska
A1 - John, T.
A1 - Paulus, B.
A1 - Braun, T.
T1 - Studies on the local structure of the F/OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy
N2 - he mutual influence of F and OH groups in neighboring sites in topaz (Al2SiO4(F,OH)2) was investigated using magic angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The splitting of 19F and 1H NMR signals, as well as the OH Raman band, provides evidence for hydrogen bond formation within the crystal structure. Depending on whether a given OH group has another OH group or fluoride as its neighbor, two different hydrogen bond constellations may form: either OH···O···HO or F···H···O. The proton accepting oxygen was determined to be part of the SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR data between an OH-bearing and an OH-free topaz sample confirms that the 19F signal at −130 ppm stems from F− ions that take part in H···F bonds with a distance of ∼ 2.4 Å, whereas the main signal at −135 ppm belongs to fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at 3644 cm−1 stems from OH groups neighboring other OH groups, whereas the sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors, which are affected by H···F bridging. The integrated intensities of these two sub-bands do not conform to the expected ratios based on probabilistic calculations from the total OH concentration. This can be explained by a difference in the polarizability of the OH bond between the different hydrogen bond constellations or partial order or unmixing of F and OH, or a combination of both. This has implications for the quantitative interpretation of Raman data on OH bonds in general and their potential use as a probe for structural (dis-)order. No indication of tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting that the investigated samples likely have nearly ideal Al/Si ratios, making them potentially useful as high-density electron microprobe reference materials for Al and Si, as well as for F.
KW - Topas
KW - NMR
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561863
DO - https://doi.org/10.5194/ejm-34-507-2022
SN - 1617-4011
VL - 34
IS - 5
SP - 507
EP - 521
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-56186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Cohen, Zina
T1 - Composition Analysis of Writing Materials in Cairo Genizah Documents
N2 - Through the application of scientific methods of analysis to a corpus of medieval manuscripts found in the Cairo Genizah, this work aims to gain a better understanding of the writing materials used by Jewish communities at that time, shedding new light not only on the production of manuscripts in the Middle Ages, but also on the life of those Jewish communities.
KW - Ink analyses
KW - Cairo Genizah
KW - X-Ray fluorescence analyses
KW - Reflectography
KW - Middle Ages
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588642
UR - https://brill.com/display/title/59331
SN - 978-90-04-44887-2
SN - 978-90-04-46935-8
SP - 1
EP - 192
PB - Brill
CY - Leiden & Boston
AN - OPUS4-58864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dariz, P.
A1 - Schmid, Thomas
T1 - Raman focal point on Roman Egyptian blue elucidates disordered cuprorivaite, green glass phase and trace compounds
N2 - The discussed comparative analyses of Roman Imperial pigment balls and fragmentary murals unearthed in the ancient cities of Aventicum and Augusta Raurica (Switzerland) by means of Raman microspectroscopy pertain to a predecessor study on trace compounds in Early Medieval Egyptian blue (St. Peter, Gratsch, South Tyrol, Northern Italy). The plethora of newly detected associated minerals of the raw materials surviving the synthesis procedure validate the use of quartz sand matching the composition of sediments transported by the Volturno river into the Gulf of Gaeta (Campania, Southern Italy) with a roasted sulphidic copper ore and a mixed-alkaline plant ash as fluxing agent. Thus, the results corroborate a monopolised pigment production site located in the northern Phlegrean Fields persisting over the first centuries A.D., this in line with statements of the antique Roman writers Vitruvius and Pliny the Elder and recent archaeological evidences. Beyond that, Raman spectra reveal through gradual peak shifts and changes of band width locally divergent process conditions and compositional inhomogeneities provoking crystal lattice disorder in the chromophoric cuprorivaite as well as the formation of a copper-bearing green glass phase, the latter probably in dependency of the concentration of alkali flux, notwithstanding that otherwise solid-state reactions predominate the synthesis.
KW - Raman microspectroscopy
KW - Egyptian blue
KW - Cuprorivaite
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559028
DO - https://doi.org/10.1038/s41598-022-19923-w
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 12
PB - Nature Publishing Group
CY - London
AN - OPUS4-55902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Yin, Huajie
A1 - Smales, Glen Jacob
A1 - Harrison, W. J.
A1 - Budd, P. M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Polymers of intrinsic microporosity - Molecular mobility and physical aging revisited by dielectric spectroscopy and X‑ray scattering
N2 - Polymers of intrinsic microporosity (PIMs) are promising candidates for the active layer in gas separation membranes due to their high permeability and reasonable permselectivity. These appealing properties originate from a microporous structure as a result of inefficient segment packing in the condensed state due to a combination of a ladder-like rigid backbone and sites of contortion. However, this class of polymers suffers from a significant decrease in the permeability with time due to physical aging, whereby typically, the permselectivity increases. The initial microporous structures approach a denser state via local rearrangements, leading to the reduction of the permeability. Hence, a detailed characterization of the molecular mobility in such materials can provide valuable information on physical aging. In this work, the dielectric behavior of PIM-1 films and their behavior upon heating (aging) were revisited by isothermal frequency scans during different heating/cooling cycles over a broad temperature range between 133 and 523 K (−140 to 250 °C). In addition, the obtained results were compared with data of samples that were annealed at ambient temperatures over different time scales. Multiple dielectric processes were observed: several relaxation processes due to local fluctuations and a Maxwell−Wagner−Sillars polarization effect related to the microporosity. The temperature dependence of the rates of all processes follows the Arrhenius law where the estimated activation energy depends on the nature of the process. The influence of the thermal history (aging) on the processes is discussed in detail.
KW - Polymers of intrinsic microporosity
PY - 2022
DO - https://doi.org/10.1021/acs.macromol.2c00934
VL - 55
SP - 7340
EP - 7350
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-55485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Anis, B.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Graphene Oxide/Polyvinyl Alcohol–Formaldehyde Composite Loaded by Pb Ions: Structure and Electrochemical Performance
N2 - An immobilization of graphene oxide (GO) into a matrix of polyvinyl formaldehyde (PVF) foam as an eco-friendly, low cost, superior, and easily recovered sorbent of Pb ions from an aqueous solution is described. The relationships between the structure and electrochemical properties of PVF/GO composite with implanted Pb ions are discussed for the first time. The number of alcohol groups decreased by 41% and 63% for PVF/GO and the PVF/GO/Pb composite, respectively, compared to pure PVF. This means that chemical bonds are formed between the Pb ions and the PVF/GO composite based on the OH groups. This bond formation causes an increase in the Tg values attributed to the formation of a strong surface complexation between adjacent layers of PVF/GO composite. The conductivity increases by about 2.8 orders of magnitude compared to the values of the PVF/GO/Pb composite compared to the PVF. This means the presence of Pb ions is the main factor for enhancing the conductivity where the conduction mechanism is changed from ionic for PVF to electronic conduction for PVF/GO and PVF/GO/Pb.
KW - Graphene oxide
KW - Polyvinyl formaldehyde
KW - Lead ions
KW - Conductivity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549588
DO - https://doi.org/10.3390/polym14112303
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-54958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bender, R.
A1 - Féron, D.
A1 - Mills, D.
A1 - Ritter, S.
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
A1 - de Graeve, I.
A1 - Dugstad, A.
A1 - Grassini, S.
A1 - Hack, T.
A1 - Halama, M.
A1 - Han, E.-H.
A1 - Harder, T.
A1 - Hinds, G.
A1 - Kittel, J.
A1 - Krieg, R.
A1 - Leygraf, C.
A1 - Martinelli, L.
A1 - Mol, A.
A1 - Neff, D.
A1 - Nilsson, J.-O.
A1 - Odnevall, I.
A1 - Paterson, S.
A1 - Paul, S.
A1 - Prošek, T.
A1 - Raupach, M.
A1 - Revilla, R. I.
A1 - Ropital, F.
A1 - Schweigart, H.
A1 - Szala, E.
A1 - Terryn, H.
A1 - Tidblad, J.
A1 - Virtanen, S.
A1 - Volovitch, P.
A1 - Watkinson, D.
A1 - Wilms, M.
A1 - Winning, G.
A1 - Zheludkevich, M.
T1 - Corrosion challenges towards a sustainable society
N2 - A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate‐resilient energy systems and infrastructures brings with it a long‐term direction, so as a result the long‐term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics.
KW - Corrosion
KW - Corrosion costs
KW - Corrosion protection
KW - Preventive strategies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554801
DO - https://doi.org/10.1002/maco.202213140
SN - 1521-4176
VL - 73
IS - 11
SP - 1730
EP - 1751
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breitenbach, Romy
A1 - Gerrits, Ruben
A1 - Dementyeva, Polina
A1 - Knabe, Nicole
A1 - Schumacher, Julia
A1 - Feldmann, Ines
A1 - Radnik, Jörg
A1 - Ryo, M.
A1 - Gorbushina, Anna
T1 - The role of extracellular polymeric substances of fungal biofilms in mineral attachment and weathering
N2 - The roles extracellular polymeric substances (EPS) play in mineral attachment and weathering were studied using genetically modified biofilms of the rock-inhabiting fungus Knufia petricola strain A95. Mutants deficient in melanin and/or carotenoid synthesis were grown as air-exposed biofilms. Extracted EPS were quantified and characterised using a combination of analytical techniques. The absence of melanin affected the quantity and composition of the produced EPS: mutants no longer able to form melanin synthesised more EPS containing fewer pullulan-related glycosidic linkages. Moreover, the melanin-producing strains attached more strongly to the mineral olivine and dissolved it at a higher rate. We hypothesise that the pullulan-related linkages, with their known adhesion functionality, enable fungal attachment and weathering. The released phenolic intermediates of melanin synthesis in the Δsdh1 mutant might play a role similar to Fe-chelating siderophores, driving olivine dissolution even further. These data demonstrate the need for careful compositional and quantitative analyses of biofilm-created microenvironments.
KW - Biofilms
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549025
DO - https://doi.org/10.1038/s41529-022-00253-1
SN - 2397-2106
VL - 6
SP - 1
EP - 11
PB - Springer Nature
CY - London
AN - OPUS4-54902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Das, Chayanika
A1 - Emmerling, Franziska
T1 - Mechanochemical Synthesis of Phosphonate-Based Proton Conducting Metal-Organic Frameworks
N2 - Water-stable metal−organic frameworks (MOFs) with proton-conducting behavior have attracted great attention as promising materials for proton-exchange membrane fuel cells. Herein, we report the mechanochemical gram-scale synthesis of three new mixed-ligand phosphonate-based MOFs, {Co(H2PhDPA)(4,4′-bipy)H2O)·2H2O}n (BAM-1), {Fe(H2PhDPA)(4,4′-bipy) (H2O)·2H2O}n (BAM-2), and {Cu(H2PhDPA)(dpe)2(H2O)2·2H2O}n (BAM-3) [where H2PhDPA = phenylene diphosphonate, 4,4′-bipy = 4,4′-bipyridine, and dpe = 1,2-di(4-pyridyl)ethylene]. Single-crystal X-ray diffraction measurements revealed that BAM-1 and BAM-2 are isostructural and possess a three-dimensional (3D) network structure comprising one-dimensional (1D) channels filled with guest water molecules. Instead, BAM-3 displays a 1D network structure extended into a 3D supramolecular structure through hydrogenbonding and π−π interactions. In all three structures, guest water molecules are interconnected with the uncoordinated acidic hydroxyl groups of the phosphonate moieties and coordinated water molecules by means of extended hydrogen-bonding interactions. BAM-1 and BAM-2 showed a gradual increase in proton conductivity with increasing temperature and reached 4.9 × 10−5 and 4.4 × 10−5 S cm−1 at 90 °C and 98% relative humidity (RH). The highest proton conductivity recorded for BAM-3 was 1.4 × 10−5 S cm−1 at 50 °C and 98% RH. Upon further heating, BAM-3 undergoes dehydration followed by a phase transition to another crystalline form which largely affects its performance. All compounds exhibited a proton hopping (Grotthuss model) mechanism, as suggested by their low activation energy.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Proton conductivity
PY - 2022
DO - https://doi.org/10.1021/acs.inorgchem.2c01023
VL - 61
SP - 10801
EP - 10809
PB - ACS Publications
AN - OPUS4-55448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spallanzani, Roberta
A1 - Koga, K.
A1 - Cichy, S.
A1 - Wiedenbeck, M.
A1 - Schmidt, B.
A1 - Oelze, Marcus
A1 - Wilke, M.
T1 - Lithium and boron difusivity and isotopic fractionation in hydrated rhyolitic melts
N2 - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that Li difusivity increases with water content. Our results on B difusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confrm that B difusivity is limited by viscous fow in silicate melts. Our results on Li and B difusion present a new tool for understanding degassing-related processes, ofering a potential geospeedometer to measure volcanic ascent rates.
KW - Hydrated silicate melts
KW - Stable isotopes
KW - Diffusion
KW - Isotopic fractionation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554496
DO - https://doi.org/10.1007/s00410-022-01937-2
VL - 177
IS - 8
SP - 1
EP - 17
PB - Springer
AN - OPUS4-55449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -