TY - JOUR A1 - Schröder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Thermodynamic prediction of precipitations behaviour in HAZ of a gas metal arc welded S690QL with varying Ti and Nb content N2 - For a significant increase in the strength of high-strength fine-grained structural steels with a nominal yield strength ≥690 MPa, the addition of microalloying elements such as Nb and Ti is required. The standard specifications for the chemical composition of these steels (e.g., in EN 10025-6) often only give the manufacturer limit contents to achieve the defined properties. The effect of the alloying elements in the heat affected zone (HAZ) is sometimes completely contrary. This makes it difficult to adequately predict the batch dependency regarding weldability and the load-bearing behaviour of the welded joint. Three different micro-alloyed steels of the grade S690QL were produced on a laboratory scale, focusing on different Nb and Ti contents. To investigate the tempering effect, these were gas metal arc welded in three layers. In addition to metallographic investigations of individual HAZ areas, thermodynamic phase calculations were carried out using Thermo-Calc, following variations in the chemical composition. This provides an understanding of phase transformation, precipitation growth, and dissolution during welding as a function of temperature and cooling conditions. The results show a divergent metallurgical behaviour in the HAZ of the three different micro-alloyed steels. Thereby, the Ti micro-alloyed grade showed a strong softening of the HAZ in contrast to the Nb micro-alloyed grade. This can be attributed to a contrary precipitation behaviour during welding. KW - High-strength structural steel KW - Gas metal arc welding KW - HAZ-softening KW - Microalloying influences KW - Thermodynamic simulation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579988 DO - https://doi.org/10.1007/s40194-023-01550-2 SN - 0043-2288 SP - 1 EP - 10 PB - Springer AN - OPUS4-57998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Tuma, Dirk A1 - Kipphardt, Heinrich A1 - Khanipour, Peyman A1 - Chamorro, C. R. T1 - Thermodynamic characterization of the (H2 + C3H8) system significant for the hydrogen economy: Experimental (p, rho, T) determination and equation-of-state modelling N2 - For the gradual introduction of hydrogen in the energy market, the study of the properties of mixtures of hydrogen with typical components of natural gas (NG) and liquefied petroleum gas (LPG) is of great importance. This work aims to provide accurate experimental (p, rho, T) data for three hydrogen-propane mixtures with nominal compositions (amount of substance, mol/mol) of (0.95 H2 + 0.05 C3H8), (0.90 H2 + 0.10 C3H8), and (0.83 H2 + 0.17 C3H8), at temperatures of 250, 275, 300, 325, 350, and 375 K, and pressures up to 20 MPa. A single-sinker densimeter was used to determine the density of the mixtures. Experimental density data were compared to the densities calculated from two reference equations of state: the GERG-2008 and the AGA8-DC92. Relative deviations from the GERG-2008 EoS are systematically larger than those from the AGA8-DC92. They are within the ±0.5% band for the mixture with 5% of propane, but deviations are higher than 0.5% for the mixtures with 10% and 17% of propane, especially at low temperatures and high pressures. Finally, the sets of new experimental data have been processed by the application of two different statistical equations of state: the virial equation of state, through the second and third virial coefficients, B(T, x) and C(T, x), and the PC-SAFT equation of state. KW - Hydrogen-containing gas mixture KW - Density data KW - Equation of state KW - Virial coefficients PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570056 DO - https://doi.org/10.1016/j.ijhydene.2022.11.170 SN - 0360-3199 VL - 48 IS - 23 SP - 8645 EP - 8667 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-57005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Martín, D. A1 - Pazoki, F. A1 - Kipphardt, Heinrich A1 - Khanipour, P. A1 - Tuma, Dirk A1 - Horillo, A. A1 - Chamorro, C. R. T1 - Thermodynamic (p, ρ, T) characterization of a reference high-calorific natural gas mixture when hydrogen is added up to 20 % (mol/mol) N2 - The injection of hydrogen into the natural-gas grid is an alternative during the process of a gradual decarbonization of the heat and power supply. When dealing with hydrogen-enriched natural gas mixtures, the performance of the reference equations of state habitually used for natural gas should be validated by using high-precision experimental thermophysical data from multicomponent reference mixtures prepared with the lowest possible uncertainty in composition. In this work, we present experimental density data for an 11-compound high-calorific (hydrogen-free) natural gas mixture and for two derived hydrogen-enriched natural gas mixtures prepared by adding (10 and 20) mol-% of hydrogen to the original standard natural gas mixture. The three mixtures were prepared gravimetrically according to ISO 6142–1 for maximum precision in their composition and thus qualify for reference materials. A single-sinker densimeter was used to determine the density of the mixtures from (250–350) K and up to 20 MPa. The experimental density results of this work have been compared to the densities calculated by three different reference equations of state for natural gas related mixtures: the AGA8-DC92 EoS, the GERG-2008 EoS, and an improved version of the GERG-2008 EoS. While relative deviations of the experimental density data for the hydrogen-free natural gas mixture are always within the claimed uncertainty of the three considered equations of state, larger deviations can be observed for the hydrogen-enriched natural gas mixtures from any of the three equations of state, especially for the lowest temperature and the highest pressures. KW - Hydrogen-enriched natural gas KW - Single-sinker densimeter KW - High-pressure density KW - Equations of state PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604742 DO - https://doi.org/10.1016/j.ijhydene.2024.05.028 SN - 0360-3199 VL - 70 SP - 118 EP - 135 PB - Elsevier BV CY - Amsterdam AN - OPUS4-60474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Smol, M. A1 - Adam, Christian A1 - Kugler, Stefan T1 - Thermochemical Treatment of Sewage Sludge Ash (SSA)—Potential and Perspective in Poland N2 - Phosphorus (P) recovery from sewage sludge ash (SSA) is one of the most promising approaches of phosphate rock substitution in mineral fertilizers and might be a sustainable way to secure supply of this raw material in the future. In the current investigation, the process of thermochemical treatment of SSA was applied to SSA coming from selected mono-incineration plants of municipal sewage sludge in Poland (Cracow, Gdansk, Gdynia, Lodz, Kielce and Szczecin). The Polish SSA was thermochemically converted in the presence of sodium (Na) additives and a reducing agent (dried sewage sludge) to obtain secondary raw materials for the production of marketable P fertilizers. The process had a positive impact on the bioavailability of phosphorus and reduced the content of heavy metals in the obtained products. The P solubility in neutral Ammonium citrate, an indicator of its bioavailability, was significantly raised from 19.7–45.7% in the raw ashes and 76.5–100% in the thermochemically treated SSA. The content of nutrients in the recyclates was in the range of 15.7–19.2% P2O5, 10.8–14.2% CaO, 3.5–5.4% Na2O, 2.6–3.6% MgO and 0.9–1.3% K2O. The produced fertilizer raw materials meet the Polish norms for trace elements covered by the legislation: the content of lead was in the range 10.2–73.1 mg/kg, arsenic 4.8–22.7 mg/kg, Cadmium 0.9–2.8 mg/kg and mercury <0.05 mg/kg. Thus, these products could be potentially directly used for fertilizer production. This work also includes an analysis of the possibilities of using ashes for fertilizer purposes in Poland, based on the assumptions indicated in the adopted strategic and planning documents regarding waste management and fertilizer production. KW - Sewage Sludge Ashes KW - Critical raw materials KW - Phosphorus KW - Fertilizer KW - Sewage Sludge PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514468 DO - https://doi.org/10.3390/en13205461 VL - 13 IS - 20 SP - 5461 AN - OPUS4-51446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Schott, M. A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Thermally induced structural rearrangement of the Fe(II) coordination geometry in metallo-supramolecular polyelectrolytes N2 - Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical process is generally reversible. The blue colour in the ground state is a result of a metal-to-ligand charge transfer at the Fe(II) centre ion in a quasi-octahedral geometry. When annealed at temperatures above 100 °C, the blue colour turns into green and the formerly reversible electrochromic properties are lost, even after cooling down to room temperature. The thermally induced changes in the Fe(II) coordination sphere are investigated in situ during annealing of a solid Fe-MEPE using X-ray absorption fine structure (XAFS) spectroscopy. The study reveals that the thermally induced transition is not accompanied by a redox process at the Fe(II) centre. From the detailed analysis of the XAFS spectra, the changes are attributed to structural changes in the coordination sphere of the Fe(II) site. In the low temperature state, the Fe(II) ion rests in a quasi-octahedral coordination environment surrounded by six nitrogen atoms of the pyridine rings. The axial Fe–N bond length is 1.94 Å, while the equatorial bond length amounts to 1.98 Å. In the high temperature state, the FeN6-site exhibits a distortion with the axial Fe–N bonds being shortened to 1.88 Å and the equatorial Fe–N bonds being elongated to 2.01 Å. KW - Metallo-supramolecular polyelectrolytes KW - Electrochromism KW - XANES KW - EXAFS KW - Local structure KW - Thermal stability PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317331 DO - https://doi.org/10.1039/c4cp01187b SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 36 SP - 19694 EP - 19701 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kovacevic, E. A1 - Strunskus, T. A1 - Santhosh, N. M. A1 - Zavasnik, Z. A1 - Unger, Wolfgang A1 - Sauvage, T. A1 - Ammar, M.-R. A1 - Cvelbar, U. A1 - Berndt, J. T1 - Thermal stability studies of plasma deposited hydrogenated carbon nitride nanostructures N2 - Thermally stable carbon nitride nanostructures have potential applications in surface coatings and automotive fields. In this work, hydrogenated nitrogen-rich carbon nitride nanoparticles have been synthesised via low-pressure low-power plasma vapour deposition technique from methane/Nitrogen gas mixture in a dry process. Thermal stability of the initially prepared hydrogenated carbon Nitride structures has been analysed by near-edge X-ray absorption fine-structure spectroscopy (NEXAFS, insitu), Raman spectroscopy, scanning and transmission electron microscopy and nuclear reaction Analysis (NRA). Thermal studies reveal the excellent stability of the material and nitrogen-rich characteristics (N/C ratio 0.5e0.2 ± 0.01). The obtained results suggest transformation of sp3-rich as-deposited carbon Nitride into sp2-carbon phase with more graphitic features upon thermal annealing. Such in-situ thermal studies of plasma deposited carbon nitrides confirm the conversion of sp3-rich phase to sp2-rich carbon phase at the critical temperature (about 450 K), without a huge loss in nitrogen content. The analysis revealed that the material is a stable plasma deposit after this critical temperature up to >1100 K. Additionally, super hydrophilic carbon nitride nanostructure transforms into a hydrophobic surface after thermal annealing. These thermally stable hydrophobic carbon nitride nanoparticles could be used as a promising material for the hydrophobic coatings for various applications, especially for harsh conditions. KW - Carbon nanoparticles KW - Hydrogenated nanostructures KW - Plasma deposition KW - NEXAFS KW - Thermal annealing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536163 DO - https://doi.org/10.1016/j.carbon.2021.08.008 SN - 0008-6223 VL - 184 SP - 82 EP - 90 PB - Elsevier Ltd. AN - OPUS4-53616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohr, Gunther A1 - Chaudry, Mohsin Ali A1 - Scheuschner, Nils A1 - Blasón Gonzalez, Sergio A1 - Madia, Mauro A1 - Hilgenberg, Kai T1 - Thermal history transfer from complex components to representative test specimens in laser powder bed fusion N2 - Additively manufactured components are characterized by heterogeneous mechanical properties due to variations of the microstructure, flaws and residual stresses resulting from the inhomogeneous fabrication process. The large number of influencing factors poses a further challenge in understanding the correlation between material properties, process parameters and component geometry. Therefore, the qualification of components based on witness specimens produced within the same job is questionable. This work aims to present a new strategy for the characterization of PBF-LB/M components based on representative specimens. The key assumption is the feasibility of a transfer of the thermal history from a component to a specimen. It is assumed that similar material properties are determined for components and specimens produced adopting a similar thermal history. After the definition of a region of interest in the component, a combination of thermal analyses by means of finite elements and in-situ experimental determination of the thermal history through infrared thermography is used to produce test coupons with a similar thermal history. The effectiveness of the procedure is demonstrated on a pressure vessel for applications in the chemical industry. KW - Additive manufacturing KW - Heat accumulation KW - Thermal history KW - In situ monitoring KW - Process simulation KW - Representative specimens PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602651 DO - https://doi.org/10.1007/s40964-024-00689-8 SN - 2363-9512 SN - 2363-9520 SP - 1 EP - 16 PB - Springer CY - Cham, Switzerland AN - OPUS4-60265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lunkenheimer, P. A1 - Loidl, A. A1 - Riechers, Birte A1 - Zaccone, A. A1 - Samwer, K. T1 - Thermal expansion and the glass transition N2 - Melting is well understood in terms of the Lindemann criterion, which essentially states that crystalline materials melt when the thermal vibrationsof their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies. Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa. KW - Glass transition KW - Lindemann criterion KW - Thermal expansion KW - Glass PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570267 DO - https://doi.org/10.1038/s41567-022-01920-5 SN - 1745-2473 SP - 1 EP - 7 PB - Nature Publishing Group CY - London AN - OPUS4-57026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von Werder, Julia A1 - Simon, Sebastian A1 - Gardei, André A1 - Fontana, P. A1 - Meng, Birgit T1 - Thermal and hydrothermal treatment of UHPC: influence of the process parameters on the phase composition of ultra-high performance concrete N2 - Several studies show that thermal and hydrothermal treatment can further improve the excellent properties of UHPC in terms of mechanical strength and durability. While for the thermal treatment the increase in strength is attributed to an intensified pozzolanic and hydraulic reaction, for the hydrothermal treatment previous studies accredited it mostly to the formation of tobermorite. In the presented study thermal and hydrothermal treatment of UHPC samples was systematically varied and the phase formation analysed related to the strength development of a reference sample cured for 28 days in water. For the thermal treatment the results show that the strength increase depends on the protection against desiccation and can be ascribed to an improved pozzolanic reaction of the siliceous fillers. To achieve a significant enhancement of strength, a pre-storage time of few days and a long dwell time at elevated temperature/pressure are required. For the hydrothermal treatment already heating the specimens up to 185 °C in saturated steam followed by an immediate cooling leads to a substantial increase in compressive strength. Pre-storage time did not affect the result as far as a minimum of several hours is guaranteed. The improved performance is due to an increase in the pozzolanic and hydraulic reaction. Surprisingly, tobermorite was only found within a very thin layer at the surface of the sample, but not in the bulk. Sulphate and aluminium stemming from the decomposition of the ettringite are bound in the newly formed phases hydroxylellestadite and hydrogarnet. KW - UHPC KW - Thermal treatment KW - Hydrothermal treatment KW - Compressive strength KW - Phase development KW - Durability KW - Tobermorite KW - Hydroxylellestadite KW - Hydrogarnet PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523402 DO - https://doi.org/10.1617/s11527-021-01633-w SN - 1871-6873 SN - 1359-5997 VL - 54 IS - 1 SP - Article 44 PB - Springer Nature AN - OPUS4-52340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tantardini, C. A1 - Michalchuk, Adam A1 - Samtsevich, A. A1 - Rota, C. A1 - Kvashnin, A. G. T1 - The Volumetric Source Function: Looking Inside van der Waals Interactions N2 - The study of van der Waals interactions plays a central role in the understanding of bonding across a range of biological, chemical and physical phenomena. The presence of van der Waals interactions can be identified through analysis of the reduced density gradient, a fundamental parameter at the core of Density Functional Theory. An extension of Bader’s Quantum Theory of Atoms in Molecules is developed here through combination with the analysis of the reduced density gradient. Through this development, a new quantum chemical topological tool is presented: the volumetric source function. This technique allows insight into the atomic composition of van der Waals interactions, offering the first route towards applying the highly successful source function to these disperse interactions. A new algorithm has been implemented in the open-source code, CRITIC2, and tested on acetone, adipic and maleic acids molecular crystals, each stabilized by van der Waals interactions. This novel technique for studying van der Waals interactions at an atomic level offers unprecedented opportunities in the fundamental study of intermolecular interactions and molecular design for crystal engineering, drug design and bio-macromolecular processes. KW - Noncovalent interactions PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507911 DO - https://doi.org/10.1038/s41598-020-64261-4 VL - 10 IS - 1 SP - 7816 AN - OPUS4-50791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natsopoulou, M. E. A1 - McMahon, Dino Peter A1 - Doublet, V. A1 - Frey, E. A1 - Rosenkranz, P. A1 - Paxton, R. J. T1 - The virulent, emerging genotype B of Deformed wing virus is closely linked to overwinter honeybee worker loss N2 - Bees are considered to be threatened globally, with severe overwinter losses of the most important commercial pollinator, the Western honeybee, a major concern in the Northern Hemisphere. Emerging infectious diseases have risen to prominence due to their temporal correlation with colony losses. Among these is Deformed wing virus (DWV), which has been frequently linked to colony mortality. We now provide evidence of a strong statistical association between overwintering colony decline in the field and the presence of DWV genotype-B (DWV-B), a genetic variant of DWV that has recently been shown to be more virulent than the original DWV genotype-A. We link the prevalence of DWV-B directly to a quantitative measure of overwinter decline (workforce mortality) of honeybee colonies in the field. We demonstrate that increased prevalence of virus infection in individual bees is associated with higher overwinter mortality. We also observed a substantial reduction of infected colonies in the spring, suggesting that virus-infected individuals had died during the winter. Our findings demonstrate that DWV-B, plus possible A/B recombinants exhibiting DWV-B at PCR primer binding sites, may be a major cause of elevated overwinter honeybee loss. Its potential emergence in naïve populations of bees may have far-reaching ecological and economic impacts. KW - Honeybee KW - Loss KW - Virulence KW - Virus PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410446 DO - https://doi.org/10.1038/s41598-017-05596-3 SN - 2045-2322 IS - 7 SP - 5242, 1 EP - 5242, 9 AN - OPUS4-41044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Thomas A1 - Traulsen, Christoph Hans-Henning A1 - Darlatt, Erik A1 - Richter, S. A1 - Poppenberg, J. A1 - Traulsen, N.L. A1 - Linder, I. A1 - Lippitz, Andreas A1 - Dietrich, Paul A1 - Dib, B. A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - The versatility of 'Click' reactions at surfaces: Molecular recognition at interfaces N2 - In order to investigate molecular recognition on surfaces, an azide-functionalized monolayer was deposited on gold. The monolayer was characterized by X-ray photoelectron spectroscopy (XPS) and angle-resolved near-edge X-ray absorption fine structure (NEXAFS) experiments and the decomposition of the azide upon irradiation with X-ray beams was investigated. Subsequently, various alkyne-functionalized host and guest molecules were attached to the azide by 1,3-dipolar cycloaddition. These modified surfaces and their host–guest chemistry were analysed by XPS and angle-resolved NEXAFS. The reversibility of guest binding was shown for one example as a proof of principle. KW - 'Click' reaction KW - Azide-terminated surfaces KW - SAMs KW - Host guest molecules KW - Molecular recognition at interfaces PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306463 DO - https://doi.org/10.1039/C4RA01730G SN - 2046-2069 VL - 4 IS - 34 SP - 17694 EP - 17702 PB - RSC Publishing CY - London AN - OPUS4-30646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen T1 - The triple-isotope calibration approach: a universal and standard-free calibration approach for obtaining absolute isotope ratios of multi-isotopic elements N2 - The theory of a new calibration approach for obtaining absolute isotope ratios of multi-isotopic elements without the use of any standard has been developed. The calibration approach basically uses the difference in the instrumental isotope fractionation of two different types of mass spectrometers, leading to two different fractionation lines in a three-isotope diagram. When measuring the same sample with both mass spectrometers, the different fractionation lines have one point in common: this is the ‘true’ logarithmized isotope ratio pair of the sample. Thus, the intersection of both fractionation lines provides us with the absolute isotope ratios of the sample. This theory has been tested in practice by measuring Cd and of Pb isotope ratios in the certified reference materials BAM-I012 and NIST SRM981 by thermal ionization mass spectrometry and by inductively coupled plasma mass spectrometry while varying the ionization conditions for both mass spectrometers. With this experiment, the theory could be verified, and absolute isotope ratios were obtained, which were metrologically compatible with the certified isotope ratios. The so-obtained absolute isotope ratios are biased by − 0.5% in average, which should be improved with further developments of the method. This calibration approach is universal, as it can be applied to all elements with three or more isotopes and it is not limited to the type of mass spectrometers applied; it can be applied as well to secondary ion mass spectrometry or others. Additionally, this approach provides information on the fractionation process itself via the triple-isotope fractionation exponent θ. KW - Triple isotope fractionation KW - Absolute isotope ratio KW - Mass spectrometry KW - Calibration KW - Uncertainty PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516364 DO - https://doi.org/10.1007/s00216-020-03050-4 VL - 413 IS - 3 SP - 821 EP - 826 PB - Springer Verlag AN - OPUS4-51636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The tribological and mechanical properties of niobium carbides (NbC) bonded with cobalt of Fe3Al N2 - The tribological and mechanical properties of niobium carbide bonded with 8 vol.-% (NbC-8Co), 12 vol.-% of cobalt (NbC-12Co) or 12 vol.-% of Fe3Al (NbC-12Fe3Al) are presented. Rotating discs made of metal-bonded niobium carbide were mated against alumina (99.7%) under unlubricated (dry) unidirectional sliding tests (0.1 m/s to 12.0 m/s; 22 °C and 400 C) as well as in oscillation tests (f=20 Hz, Δx=0.2 mm, 2/50/98% rel. humidity, n=105/106 cycles). Microstructure and phase compositions were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where NbC bonded with 8% and 12% Co presented above 7 m/s the lowest wear rates so far in such a benchmark. Binderless NbC (HP-NbC1) and the metal-bonded NbCs exhibited low wear rates under dry sliding associated with P·V high load carrying capacities. NbC-based hard metal bonded with 12 vol.-% of Fe3Al resulted in a higher hardness level than for 12 vol.-% cobalt. The tribological profile established revealed a strong position of NbC-bearing materials under tribological considerations and for closed tribosystems against established reference tribo-couples. KW - Sliding KW - Ceramic KW - Oscillation KW - Strength KW - Modulus KW - High temperatures KW - Friction KW - Wear KW - NbC KW - Niobium carbide KW - Cobalt KW - Fe3Al KW - Hard metal PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316129 DO - https://doi.org/10.1016/j.wear.2014.09.007 SN - 0043-1648 VL - 321 SP - 1 EP - 7 PB - Elsevier CY - Amsterdam AN - OPUS4-31612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bente, Klaas T1 - The thermoacoustic effect and its application in air-coupled testing of composite structures N2 - Airborne ultrasonic testing of lightweight, structured composite materials enables fast and contact-free non-destructive testing in aerospace and avoids material degradation due to contact with a coupling liquid. Established resonant air-coupled transducers consist of piezocomposite materials and several matching layers or more advanced materials like charged cellular polypropylene. The relaxation time and the specific frequency of such mechanical ultrasound emitters limit the spectrum of applications for each device. A short pulse length is key for reliable defect detection and each component at test can be best characterized at material- and geometry-specific frequencies. Here we show that focused thermoacoustic transducers are suited for testing lightweight, structured composite plates. Since the ultrasound is generated in air, these transducers show no resonance behavior and emit a broadband acoustic spectrum between 1.2 kHz and 1 MHz. Composite specimens of 3 mm to 9 mm thickness made of polylactide with a honeycomb structure were tested. Flat bottom holes were introduced to quantify the spatial resolution of the imaging method inside the strongly anisotropic specimen. As no broadband receivers are available yet, cellular polypropylene transducers were used as receivers, which limits the bandwidth of the method towards the bandwidth of the receiver. Nevertheless, we demonstrate the competitiveness of the thermoacoustic transducer compared to mechanical emitters at their respective resonance frequencies. Because a thermoacoustic transmitter features a nearly ideal pulse width, a single transmitter can be coupled with receivers with different resonance frequencies. With the development of broadband ultrasound receivers, air-coupled ultrasound spectroscopy will likely be possible in the near future. The analysed transducer holds the potential to speed up testing during production and maintenance in aerospace and automotives. Its combination with a broadband receiver could also expand the application field of air-coupled ultrasonic testing from a qualitative error detection towards a quantitative, spatially resolved analysis of mechanical material properties. T2 - 10th International Symposium on NDT in Aerospace CY - Dresden, Germany DA - 24.10.2018 KW - Thermoacoustics KW - Ultrasonic Testing KW - Broadband KW - Ultrasound Emission PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464677 SN - 978-3-940283-96-2 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-46467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menga, D. A1 - Low, Jian Liang A1 - Guilherme Buzanich, Ana A1 - Paulus, B. A1 - Fellinger, Tim-Patrick T1 - The Tetrapyrollic Motif in Nitrogen Doped Carbons and M-N-C Electrocatalysts as Active Site in the Outer-Sphere Mechanism of the Alkaline Oxygen Reduction Reaction N2 - Development and fundamental understanding of precious-group-metal-free electrocatalysts is hampered by limitations in the quantification of the intrinsic activity of different catalytic sites and understanding the different reaction mechanisms. Comparing isomorphic nitrogen-doped carbons, Zn-N-Cs and Fe-N-Cs with the common tetrapyrrolic motif, a catalyst-independent outer-sphere rate-determining step in the alkaline oxygen reduction reaction is observed. Density functional theory (DFT) simulations on tetrapyrrolic model structures indicate the highest occupied molecular orbital (HOMO) level as a good descriptor for the catalytic activity. Contour plots suggest that the electron transfer occurs directly from the tetrapyrrolic coordination site, rather than from the metal center. Metal-free tetrapyrrolic N4 sites are discovered to be highly active oxygen reduction reaction (ORR) active sites in alkaline that reach turnover frequencies (TOF) of 0.33 and 1.84 s−1 at 0.80 and 0.75 VRHE in the order of magnitude of tetrapyrrolic Fe–N4 sites in the acidic ORR. While Zn-coordination lowers the HOMO level and therefore the catalytic activity, Fe-coordination lifts the HOMO level resulting in TOF values of 0.4 and 4 s−1 for tetrapyrrolic Fe–N4 sites at 0.90 and 0.85 VRHE, respectively. At higher mass activities, the peroxide reduction becomes rate-limiting, where highest peroxide production rates are observed for the nitrogen-doped carbon. KW - Tetrapyrollic KW - Motif KW - Nitrogen KW - Carbons KW - Alkaline Oxygen PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606239 DO - https://doi.org/https://doi.org/10.1002/aenm.202400482 SN - 1614-6832 VL - 2024 SP - 1 EP - 8 PB - Wiley-VCH AN - OPUS4-60623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - MacLean, J. A1 - Mayanna, S. A1 - Benning, L. G. A1 - Horn, F. A1 - Bartholomäus, A. A1 - Wiesner, Yosri A1 - Wagner, D. A1 - Liebner, S. T1 - The terrestrial plastisphere: Diversity and polymer-colonizing potential of plastic-associated microbial communities in soil N2 - The concept of a ‘plastisphere microbial community’ arose from research on aquatic plastic debris, while the effect of plastics on microbial communities in soils remains poorly understood. Therefore, we examined the inhabiting microbial communities of two plastic debris ecosystems with regard to their diversity and composition relative to plastic-free soils from the same area using 16S rRNA amplicon sequencing. Furthermore, we studied the plastic-colonizing potential of bacteria originating from both study sites as a measure of surface adhesion to UV-weathered polyethylene (PE) using high-magnification field emission scanning electron microscopy (FESEM). The high plastic content of the soils was associated with a reduced alpha diversity and a significantly different structure of the microbial communities. The presence of plastic debris in soils did not specifically enrich bacteria known to degrade plastic, as suggested by earlier studies, but rather shifted the microbial community towards highly abundant autotrophic bacteria potentially tolerant to hydrophobic environments and known to be important for biocrust formation. The bacterial inoculates from both sites formed dense biofilms on the surface and in micrometer-scale surface cracks of the UV-weathered PE chips after 100 days of in vitro incubation with visible threadlike EPS structures and cross-connections enabling surface adhesion. High-resolution FESEM imaging further indicates that the microbial colonization catalyzed some of the surface degradation of PE. In essence, this study suggests the concept of a ‘terrestrial plastisphere’ as a diverse consortium of microorganisms including autotrophs and other pioneering species paving the way for those members of the consortium that may eventually break down the plastic compounds. KW - Soil microbial community KW - Polyethylene colonization KW - Plastic pollution PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542790 DO - https://doi.org/10.3390/microorganisms9091876 VL - 9 IS - 9 SP - 1 EP - 19 PB - MDPI CY - Basel AN - OPUS4-54279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schütz, R. A1 - Maragh, J. A1 - Weaver, J. A1 - Rabin, Ira A1 - Masic, A. T1 - The Temple Scroll: Reconstructing an ancient manufacturing practice N2 - The miraculously preserved 2000-year-old Dead Sea Scrolls, ancient texts of invaluable historical significance, were discovered in the mid-20th century in the caves of the Judean desert. The texts were mainly written on parchment and exhibit vast diversity in their states of preservation. One particular scroll, the 8-m-long Temple Scroll is especially notable because of its exceptional thinness and bright ivory color. The parchment has a layered structure, consisting of a collagenous base material and an atypical inorganic overlayer. We analyzed the chemistry of the inorganic layer using x-ray and Raman spectroscopies and discovered a variety of evaporitic sulfate salts. This points toward a unique ancient production technology in which the parchment was modified through the addition of the inorganic layer as a writing surface. Furthermore, understanding the properties of these minerals is particularly critical for the development of suitable conservation methods for the preservation of these invaluable historical documents. KW - Temple Scroll KW - Dead Sea Scrolls PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-495314 DO - https://doi.org/10.1126/sciadv.aaw7494 VL - 5 IS - 9 SP - 1 EP - 9 PB - AAAS AN - OPUS4-49531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Coplen, T. B. A1 - Holden, N. E. A1 - Ding, T. A1 - Meijer, H. A. J. A1 - Vogl, Jochen A1 - Zhu, X. T1 - The Table of Standard Atomic Weights—An exercise in consensus N2 - The present Table of Standard Atomic Weights (TSAW) of the elements is perhaps one of the most familiar data sets in science. Unlike most parameters in physical science whose values and uncertainties are evaluated using the “Guide to the Expression of Uncertainty in Measurement” (GUM), the majority of standard atomic weight values and their uncertainties are consensus values, not GUM-evaluated values. The Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) regularly evaluates the literature for new isotopic-abundance measurements that can lead to revised standard atomic-weight values, Ar(E) for element E. The Commission strives to provide utmost clarity in products it disseminates, namely the TSAW and the Table of Isotopic Compositions of the Elements (TICE). In 2016, the Commission recognized that a guideline recommending the expression of uncertainty listed in parentheses following the standard atomic-weight value, for example, Ar(Se) = 78.971(8), did not agree with the GUM, which suggests that this parenthetic notation be reserved to express standard uncertainty, not the expanded uncertainty used in the TSAW and TICE. In 2017, to eliminate this noncompliance with the GUM, a new format was adopted in which the uncertainty value is specified by the “±” symbol, for example, Ar(Se) = 78.971 ± 0.008. To clarify the definition of uncertainty, a new footnote has been added to the TSAW. This footnote emphasizes that an atomic-weight uncertainty is a consensus (decisional) uncertainty. Not only has the Commission shielded users of the TSAW and TICE from unreliable measurements that appear in the literature as a result of unduly small uncertainties, but the aim of IUPAC has been fulfilled by which any scientist, taking any natural sample from commerce or research, can expect the sample atomic weight to lie within Ar(E) ± its uncertainty almost all of the time. KW - Atomic weight KW - Standard atomic weight KW - Uncertainty PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551299 DO - https://doi.org/10.1002/rcm.8864 SN - 1097-0231 VL - 36 IS - 15 SP - 1 EP - 15 PB - Wiley AN - OPUS4-55129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Titirici, M. A1 - Baird, S. G. A1 - Sparks, T. D. A1 - Yang, S. M. A1 - Brandt-Talbot, A. A1 - Hosseinaei, O. A1 - Harper, D. P. A1 - Parker, R. M. A1 - Vignolini, S. A1 - Berglund, L. A. A1 - Li, Y. A1 - Gao, H.-L. A1 - Mao, L.-B. A1 - Yu, S.-H. A1 - Díez, N. A1 - Ferrero, G. A. A1 - Sevilla, M. A1 - Szilágyi, P. Á. A1 - Stubbs, C. J. A1 - Worch, J. C. A1 - Huang, Y. A1 - Luscombe, C. K. A1 - Lee, K.-Y. A1 - Luo, H. A1 - Platts, M. J. A1 - Tiwari, D. A1 - Kovalevskiy, D. A1 - Fermin, D. J. A1 - Au, H. A1 - Alptekin, H. A1 - Crespo-Ribadeneyra, M. A1 - Ting, V. P. A1 - Fellinger, Tim-Patrick A1 - Barrio, J. A1 - Westhead, O. A1 - Roy, C. A1 - Stephens, I. E. L. A1 - Nicolae, S. A. A1 - Sarma, S. C. A1 - Oates, R. P. A1 - Wang, C.-G. A1 - Li, Z. A1 - Loh, X. J. A1 - Myers, R. J. A1 - Heeren, N. A1 - Grégoire, A. A1 - Périssé, C. A1 - Zhao, X. A1 - Vodovotz, Y. A1 - Earley, B. A1 - Finnveden, G. A1 - Björklund, A. A1 - Harper, G. D. J. A1 - Walton, A. A1 - Anderson, P. A. T1 - The sustainable materials roadmap N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability. KW - Electrochemistry KW - Fe-N-C catalysts KW - Fuel cells KW - Catalysis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126 DO - https://doi.org/10.1088/2515-7639/ac4ee5 SN - 2515-7639 VL - 5 IS - 3 SP - 1 EP - 98 PB - IOP Publishing CY - Bristol AN - OPUS4-55012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -