TY - JOUR A1 - Völker, Christoph A1 - Firdous, R. A1 - Kruschwitz, Sabine A1 - Stephan, D. T1 - Sequential learning to accelerate discovery of alkali-activated binders N2 - Alkali-activated binders (AAB) can provide a clean alternative to conventional cement in terms of CO2 emissions. However, as yet there are no sufficiently accurate material models to effectively predict the AAB properties, thus making optimal mix design highly costly and reducing the attractiveness of such binders. This work adopts sequential learning (SL) in high-dimensional material spaces (consisting of composition and processing data) to find AABs that exhibit desired properties. The SL approach combines machine learning models and feedback from real experiments. For this purpose, 131 data points were collected from different publications. The data sources are described in detail, and the differences between the binders are discussed. The sought-after target property is the compressive strength of the binders after 28 days. The success is benchmarked in terms of the number of experiments required to find materials with the desired strength. The influence of some constraints was systematically analyzed, e.g., the possibility to parallelize the experiments, the influence of the chosen algorithm and the size of the training data set. The results show the advantage of SL, i.e., the amount of data required can potentially be reduced by at least one order of magnitude compared to traditional machine learning models, while at the same time exploiting highly complex information. This brings applications in laboratory practice within reach. KW - Alkali-activated binders KW - Machine learning KW - Sequential learning KW - Materials by design KW - Materials informatics PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531376 DO - https://doi.org/10.1007/s10853-021-06324-z SN - 0022-2461 SN - 1573-4803 VL - 56 SP - 15859 EP - 15881 PB - Springer CY - Dordrecht AN - OPUS4-53137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Kranzmann, Axel T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion KW - Corrosion fatigue KW - Carbon capture and storage PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391 DO - https://doi.org/10.3390/pr9040594 SN - 2227-9717 VL - 9 IS - 4 SP - 1 EP - 33 PB - MDPI CY - Basel AN - OPUS4-53139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tokarski, T. A1 - Nolze, Gert A1 - Winkelmann, A. A1 - Rychlowski, L. A1 - Bala, P. A1 - Cios, G. T1 - Transmission Kikuchi diffraction: The impact of the signal-to-noise ratio N2 - Signal optimization for transmission Kikuchi diffraction (TKD) measurements in the scanning electron microscope is investigated by a comparison of different sample holder designs. An optimized design is presented, which uses a metal shield to efficiently trap the electron beam after transmission through the sample. For comparison, a second holder configuration allows a significant number of the transmitted electrons to scatter back from the surface of the sample holder onto the diffraction camera screen. It is shown that the secondary interaction with the sample holder leads to a significant increase in the background level, as well as to additional noise in the final Kikuchi diffraction signal. The clean TKD signal of the optimized holder design with reduced background scattering makes it possible to use small signal changes in the range of 2% of the camera full dynamic range. As is shown by an analysis of the power spectrum, the signal-to-noise ratio in the processed Kikuchi diffraction patterns is improved by an order of magnitude. As a result, the optimized design allows an increase in pattern signal to noise ratio which may lead to increase in measurement speed and indexing reliability. KW - EBSD KW - SEM KW - Transmission Kikuchi diffraction KW - Sample holder PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531743 DO - https://doi.org/10.1016/j.ultramic.2021.113372 SN - 0304-3991 SN - 1879-2723 VL - 230 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-53174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tabaka, Weronika A1 - Timme, Sebastian A1 - Lauterbach, Tobias A1 - Medina, L. A1 - Berglund, L. A. A1 - Carosio, F. A1 - Duquesne, S. A1 - Schartel, Bernhard T1 - Bench-scale fire stability testing - Assessment of protective systems on carbon fibre reinforced polymer composites N2 - Fire resistance testing of components made of carbon fibre reinforced polymers (CFRP) usually demands intermediate-scale or full-scale testing. A bench-scale test is presented as a practicable and efficient method to assess how different fire protective systems improve the structural integrity of CFRPs during fire. The direct flame of a fully developed fire was applied to one side of the CFRP specimen, which was simultaneously loaded with compressive force. Three different approaches (film, non-woven, and coatings) were applied: paper with a thickness in the range of μm consisting of cellulose nanofibre (CNF)/clay nanocomposite, nonwoven mats with thickness in the range of cm and intumescent coatings with a thickness in the range of mm. The uncoated specimen failed after just 17 s. Protection by these systems provides fire stability, as they multiply the time to failure by as much as up to 43 times. The reduced heating rates of the protected specimens demonstrate the reduced heat penetration, indicating the coatings’ excellent heat shielding properties. Bench-scale fire stability testing is shown to be suitable tool to identify, compare and assess different approaches to fire protection. KW - Fire stability KW - Bench-scale fire resistance KW - Carbon fibre reinforced polymer KW - Protective coatings PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532401 DO - https://doi.org/10.1016/j.polymertesting.2021.107340 SN - 0142-9418 SN - 1873-2348 VL - 102 SP - 7340 PB - Elsevier CY - Amsterdam AN - OPUS4-53240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Distributed fiber optic radiation sensors N2 - In this work, we present our results achieved in several research activities for development of distributed fiber optic radiation sensors using glass and polymer optical fibers. The findings show that both the measurement of the radiation-induced attenuation (RIA) along the entire sensing fiber and the accompanying change in the refractive index of the fiber core can be used for distributed radiation monitoring. T2 - safeND CY - Online meeting DA - 10.11.2021 KW - Distributed fiber optic radiation sensors KW - Radiation-induced attenuation KW - Optical fiber sensor KW - Incoherent optical frequency domain reflectometry PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537531 DO - https://doi.org/10.5194/sand-1-15-2021 VL - 1 SP - 15 EP - 16 AN - OPUS4-53753 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dariz, P. A1 - Schmid, Thomas T1 - Trace compounds in Early Medieval Egyptian blue carry information on provenance, manufacture, application, and ageing N2 - Only a few scientific evidences for the use of Egyptian blue in Early Medieval wall paintings in Central and Southern Europe have been reported so far. The monochrome blue fragment discussed here belongs to the second church building of St. Peter above Gratsch (South Tyrol, Northern Italy, fifth/ sixth century A.D.). Beyond cuprorivaite and carbon black (underpainting), 26 accessory minerals down to trace levels were detected by means of Raman microspectroscopy, providing unprecedented insights into the raw materials blend and conversion reactions during preparation, application, and ageing of the pigment. In conjunction with archaeological evidences for the manufacture of Egyptian blue in Cumae and Liternum and the concordant statements of the antique Roman writers Vitruvius and Pliny the Elder, natural impurities of the quartz sand speak for a pigment produced at the northern Phlegrean Fields (Campania, Southern Italy). Chalcocite (and chalcopyrite) suggest the use of a sulphidic copper ore, and water-insoluble salts a mixed-alkaline flux in the form of plant ash. Not fully reacted quartz crystals partly intergrown with cuprorivaite and only minimal traces of silicate glass portend solid-state reactions predominating the chemical reactions during synthesis, while the melting of the raw materials into glass most likely played a negligible role. KW - Egyptian blue KW - Raman microspectroscopy KW - Spectoscopic imaging KW - Cuprorivaite KW - Amorphous carbon PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537591 DO - https://doi.org/10.1038/s41598-021-90759-6 VL - 11 SP - 1 EP - 12 PB - Nature Portfolio AN - OPUS4-53759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, Thomas A1 - Kraft, Ronja A1 - Dariz, P. T1 - Shedding light onto the spectra of lime - Part 2: Raman spectra of Ca and Mg carbonates and the role of d-block element luminescence N2 - We previously described the observation of a characteristic narrowband red luminescence emission of burnt lime (CaO), whose reason was unknown so far. This study presents Raman spectra of Mg5 CO3)4(OH)2∙4H2O, Mg5(CO3)4(OH)2, MgCO3, CaMgCO3 and CaCO3 (in limestone powder) as well as luminescence spectra of their calcination products. Comparison of the latter revealed MgO:Cr3+ as the source of the red lime luminescence in all studied samples, containing magnesium oxide as major component, minor component or trace. Spectral characteristics and theoretical background of the luminescence emission of d-block elements integrated in crystal lattices are discussed with the aim of sharpening the awareness for this effect in the Raman community and promoting its application in materials analysis. The latter is demonstrated by the Raman microspectroscopic imaging of the distributions of both Raman-active and Raman-inactive phases in clinker remnants in a 19th-century meso Portland cement mortar sample, which contain relatively high amounts of free lime detected in the form of both luminescing CaO and Raman-scattering Ca(OH)2, owing to exposure of the surface of the thin section to humid air. A combination of light and Raman spectroscopy revealed a calcium–magnesium–iron sulphide phase, indicating sulphurous raw materials and/or solid fuels employed in the calcination process, which in contrast to previously described morphologies of sulphides in cement clinker form extensive greenish black layers on free lime crystals. KW - Calcium carbonates KW - Raman spectroscopy KW - Luminescence KW - Magnesium carbonates KW - Meso Portland cement PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537611 DO - https://doi.org/10.1002/jrs.6174 SN - 0377-0486 VL - 52 IS - 8 SP - 1462 EP - 1472 PB - Wiley Analytical Science AN - OPUS4-53761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, Thomas A1 - Hidde, Julia A1 - Grünier, Sophie A1 - Jungnickel, Robert A1 - Dariz, P. A1 - Riedel, Jens A1 - Neuhaus, B. T1 - Ageing effects in mountig media of microscope slide samples from natural history collections: A case study with Canada balsam and Permount™ N2 - Microscope slide collections represent extremely valuable depositories of research material in a natural history, forensic, veterinary, and medical context. Unfortunately, most mounting media of these slides deteriorate over time, with the reason for this not yet understood at all. In this study, Raman spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, and different types of light microscopy were used to investigate the ageing behaviour of naturally aged slides from museum collections and the experimentally aged media of Canada balsam and Permount™, representing a natural and a synthetic resin, respectively, with both being based on mixtures of various terpenes. Whereas Canada balsam clearly revealed chemical ageing processes, visible as increasing colouration, Permount™ showed physical deterioration recognisable by the increasing number of cracks, which even often impacted a mounted specimen. Noticeable changes to the chemical and physical properties of these mounting media take decades in the case of Canada balsam but just a few years in the case of Permount™. Our results question whether or not Canada balsam should really be regarded as a mounting medium that lasts for centuries, if its increasing degree of polymerisation can lead to a mount which is no longer restorable. KW - Deterioration KW - Microscope slides KW - Mounting media KW - Raman spectroscopy KW - UV–Vis spectroscopy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537632 DO - https://doi.org/10.3390/polym13132112 VL - 13 IS - 13 SP - 1 EP - 27 PB - MDPI CY - Basel AN - OPUS4-53763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Heyn, L. A1 - Jung, Christian T1 - Indoor exposure to airborne polycyclic aromatic hydrocarbons: A comparison of stir bar sorptive extraction and pump sampling N2 - Stir bar sorptive extraction (SBSE) was compared with standardized pump sampling regarding the prospects to assess airborne levels of polycyclic aromatic hydrocarbons (PAHs) in indoor environments. A historic railway water tower, which will be preserved as a technical monument for museum purposes, was sampled with both approaches because the built-in insulationmaterial was suspected to release PAHs to the indoor air. The 16 PAHs on the US EPA list were quantified using gas chromatography with mass spectrometric detection in filters from pump sampling after solvent extraction and on SBSE devices after thermal desorption. SBSEwas seen to sample detectable PAHmasseswith excellent repeatability and a congener pattern largely similar to that observed with pump sampling. Congener patterns were however significantly different from that in the PAH source because release from the insulation material is largely triggered by the respective congener vapor pressures. Absolute masses in the ng range sampled by SBSE corresponded to airborne concentrations in the ng L−1 range determined by pump sampling. Principle differences between SBSE and pump sampling as well as prospects of SBSE as cost-effective and versatile complement of pump sampling are discussed. KW - Polycyclic aromatic hydrocarbons KW - Adsorption KW - Extraction KW - Indoor air PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537427 DO - https://doi.org/10.1002/eng2.12419 VL - 3 IS - 12 SP - 1 EP - 10 PB - John Wiley & Sons Ltd. AN - OPUS4-53742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Van Den Bossche, T. A1 - Arntzen, M. O. A1 - Becher, D. A1 - Benndorf, D. A1 - Eijsink, V. G. H. A1 - Henry, C. A1 - Jagtap, P. D. A1 - Jehmlich, N. A1 - Juste, C. A1 - Kunath, B. J. A1 - Mesuere, B. A1 - Muth, Thilo A1 - Pope, P. B. A1 - Seifert, J. A1 - Tanca, A. A1 - Uzzau, S. A1 - Wilmes, P. A1 - Hettich, R. L. A1 - Armengaud, J. T1 - The Metaproteomics Initiative: a coordinated approach for propelling the functional characterization of microbiomes N2 - Through connecting genomic and metabolic information, metaproteomics is an essential approach for understanding how microbiomes function in space and time. The international metaproteomics community is delighted to announce the launch of the Metaproteomics Initiative (www.metaproteomics.org), the goal of which is to promote dissemination of metaproteomics fundamentals, advancements, and applications through collaborative networking in microbiome research. The Initiative aims to be the central information hub and open meeting place where newcomers and experts interact to communicate, standardize, and accelerate experimental and bioinformatic methodologies in this feld. We invite the entire microbiome community to join and discuss potential synergies at the interfaces with other disciplines, and to collectively promote innovative approaches to gain deeper insights into microbiome functions and dynamics. KW - Microbiome KW - Metaproteomics KW - Networking KW - Meta-Omics KW - Interactions KW - Education PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542290 DO - https://doi.org/10.1186/s40168-021-01176-w VL - 9 IS - 1 SP - 243 PB - BMC AN - OPUS4-54229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ecke, Alexander A1 - Westphalen, Tanja A1 - Hornung, J. A1 - Voetz, M. A1 - Schneider, Rudolf T1 - A rapid magnetic bead-based immunoassay for sensitive determination of diclofenac N2 - Increasing contamination of environmental waters with pharmaceuticals represents an emerging threat for the drinking water quality and safety. In this regard, fast and reliable analytical methods are required to allow quick countermeasures in case of contamination. Here, we report the development of a magnetic bead-based immunoassay (MBBA) for the fast and cost-effective determination of the analgesic diclofenac (DCF) in water samples, based on diclofenac-coupled magnetic beads and a robust monoclonal anti-DCF antibody. A novel synthetic strategy for preparation of the beads resulted in an assay that enabled for the determination of diclofenac with a significantly lower limit of detection (400 ng/L) than the respective enzyme-linked immunosorbent assay (ELISA). With shorter incubation times and only one manual washing step required, the assay demands for remarkably shorter time to result (< 45 min) and less equipment than ELISA. Evaluation of assay precision and accuracy with a series of spiked water samples yielded results with low to moderate intra- and inter-assay variations and in good agreement with LC–MS/MS reference analysis. The assay principle can be transferred to other, e.g., microfluidic, formats, as well as applied to other analytes and may replace ELISA as the standard immunochemical method. KW - Immunoassay KW - Magnetic beads KW - Diclofenac KW - Water analysis KW - LC-MS/MS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542346 DO - https://doi.org/10.1007/s00216-021-03778-7 SN - 1618-2650 VL - 414 SP - 1563 EP - 1573 PB - Springer CY - Heidelberg AN - OPUS4-54234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chan, Yin Yam A1 - Ma, C. A1 - Zhou, F. A1 - Hu, Y. A1 - Schartel, Bernhard T1 - A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam N2 - A systematic series of flexible polyurethane foams (FPUF) with different concentrations of flame retardants, bis([dimethoxyphosphoryl]methyl) phenyl phosphate (BDMPP), and melamine (MA) or expandable graphite (EG) was prepared. The mechanical properties of the FPUFs were evaluated by a universal testing machine. The pyrolysis behaviors and the evolved gas analysis were done by thermogravimetric analysis (TGA) and TGA coupled with Fourier-transform infrared (TG-FTIR), respectively. The fire behaviors were studied by limiting oxygen index (LOI), UL 94 test for horizontal burning of cellular materials (UL 94 HBF), and cone calorimeter measurement. Scanning electronic microscopy (SEM) was used to examine the cellular structure's morphology and the postfire char residue of the FPUFs. LOI and UL 94 HBF tests of all the flame retarded samples show improved flame retardancy. BDMPP plays an essential role in the gas phase because it significantly reduces the effective heat of combustion (EHC). This study highlights the synergistic effect caused by the combination of BDMPP and EG. The measured char yield from TGA is greater than the sum of individual effects. No dripping phenomenon occurs during burning for FPUF-BDMPP-EGs, as demonstrated by the result of the UL 94 HBF test. EG performs excellently on smoke suppression during burning, as evident in the result of the cone calorimeter test. MA reduces the peak heat release rate (pHRR) significantly. The synergistic effect of the combination of BDMPP and EG as well as MA offers an approach to enhance flame retardancy and smoke suppression. KW - Bis([dimethoxyphosphoryl]methyl) phenyl phosphate KW - Expandable graphite KW - Flexible polyurethane foam KW - melamine KW - phosphorous flame retardant PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541840 DO - https://doi.org/10.1002/pat.5519 SN - 1099-1581 VL - 33 IS - 1 SP - 326 EP - 339 PB - Wiley AN - OPUS4-54184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chubarenko, B. A1 - Kileso, A. A1 - Esiukova, E. A1 - Pinchuk, V. A1 - Simon, Franz-Georg T1 - Dataset on geosynthetic material debris contamination of the South-East Baltic shore N2 - The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018–2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections: (1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions [1 List_geosynthetic_debris_SEB], (2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018–2020 [2 Monitoring_geosynthetic_debris_SEB]; (3) statistical distributions of the found geosynthetic debris by size [3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast. All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET-RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55-76002 ERA_a, BMBF 01DJ18005). KW - Geosynthetics KW - Geotextiles KW - Contamination KW - Marine littering PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541947 DO - https://doi.org/10.1016/j.dib.2021.107778 SN - 2352-3409 VL - 40 SP - 1 EP - 7 PB - Elsevier Inc. CY - Amsterdam AN - OPUS4-54194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cros, A. A1 - Alfaro Espinoza, Gabriela A1 - De Maria, A. A1 - Wirth, N. T. A1 - Nikel, P. I. T1 - Synthetic metabolism for biohalogenation N2 - The pressing need for novel bioproduction approaches faces a limitation in the number and type of molecules accessed through synthetic biology. Halogenation is widely used for tuning physicochemical properties of molecules and polymers, but traditional halogenation chemistry often lacks specificity and generates harmful by-products. Here, we pose that deploying synthetic metabolism tailored for biohalogenation represents an unique opportunity towards economically attractive and environmentally friendly organohalide production. On this background, we discuss growth-coupled selection of functional metabolic modules that harness the rich repertoire of biosynthetic and biodegradation capabilities of environmental bacteria for in vivo biohalogenation. By rationally combining these approaches, the chemical landscape of Living cells can accommodate bioproduction of added-value organohalides which, as of today, are obtained by traditional chemistry. KW - Halogenation KW - Synthetic metabolism PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542013 DO - https://doi.org/10.1016/j.copbio.2021.11.009 SN - 0958-1669 SN - 1879-0429 VL - 74 SP - 180 EP - 193 PB - Elsevier CY - Amsterdam AN - OPUS4-54201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dzekan, D. A1 - Waske, Anja A1 - Nielsch, K. A1 - Fähler, S. T1 - Efficient and affordable thermomagnetic materials for harvesting low grade waste heat N2 - Industrial processes release substantial quantities of waste heat, which can be harvested to generate electricity. At present, the conversion of low grade waste heat to electricity relies solely on thermoelectric materials, but such materials are expensive and have low thermodynamic efficiencies. Although thermomagnetic materials may offer a promising alternative, their performance remains to be evaluated, thereby hindering their real-world application. Here, the efficiency and cost effectiveness of thermomagnetic materials are evaluated for the usage in motors, oscillators, and generators for converting waste heat to electricity. The analysis reveals that up to temperature differences of several 10 K, the best thermomagnetic materials have the potential to compete with thermoelectric materials. Importantly, it is found that the price per watt of some thermomagnetic materials is much lower compared to that of present-day thermoelectrics, which can become competitive with conventional power plants. This materials library enables the selection of the best available thermomagnetic materials for harvesting waste heat and gives guidelines for their future development. KW - Waste heat conversion KW - Magnetic materials KW - Thermomagnetic generator PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541493 DO - https://doi.org/10.1063/5.0033970 VL - 9 SP - 1 EP - 9 PB - AIP Publishing CY - Melville, USA AN - OPUS4-54149 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja T1 - Improving Learning Outcome for GSL (German as a Second Language) Students in a Blended Learning Cumulative Assessment Material Science Course N2 - First year students especially with migration background and language deficiencies rate material science in mechanical engineering as one of the fundamental courses with high work load and necessity of language skills due to the descriptive nature of the course. Therefore a blended learning course structure using based on inverted classroom teaching scenarios was established. Heart of the self-study period are visualizing peer-to-peer lecture films supported by micro-lectures along with various online teaching materials. Although students with migration background generally scored lower in tests due to the lack of language skills improved learning outcomes are demonstrated in high quality class discussions and in overall understanding. This paper introduces the learning structure and graded activities, evaluates the course and compares results of native German-speaking students to those of students with migration background. KW - Portfolio KW - Diversity KW - Blended learning KW - Inverted classroom KW - Lecture films PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541557 DO - https://doi.org/10.17706/ijeeee.2021.11.3.93-100 SN - 2010-3654 VL - 11 IS - 3 SP - 93 EP - 100 AN - OPUS4-54155 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Wolf, M. A1 - Kranzmann, Axel T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied. KW - Steel KW - High alloyed steel KW - Corrosion fatigue KW - Cabon capture and storage KW - CCS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541626 DO - https://doi.org/10.3390/pr9040594 VL - 9 IS - 4 SP - 594 PB - MDPI AN - OPUS4-54162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ivanov, S. A1 - Artinov, Antoni A1 - Zemlyakov, E. A1 - Karpov, I. A1 - Rylov, S. A1 - Em, V. T1 - Spatiotemporal Evolution of Stress Field during Direct Laser Deposition of Multilayer Thin Wall of Ti-6Al-4V N2 - The present work seeks to extend the level of understanding of the stress field evolution during direct laser deposition (DLD) of a 3.2 mm thick multilayer wall of Ti-6Al-4V alloy by theoretical and experimental studies. The process conditions were close to the conditions used to produce large-sized structures by the DLD method, resulting in specimens having the same thermal history. A simulation procedure based on the implicit finite element method was developed for the theoretical study of the stress field evolution. The accuracy of the simulation was significantly improved by using experimentally obtained temperature-dependent mechanical properties of the DLD-processed Ti-6Al4V alloy. The residual stress field in the buildup was experimentally measured by neutron diffraction. The stress-free lattice parameter, which is decisive for the measured stresses, was determined using both a plane stress approach and a force-momentum balance. The influence of the inhomogeneity of the residual stress field on the accuracy of the experimental measurement and the validation of the simulation procedure are analyzed and discussed. Based on the numerical results it was found that the non-uniformity of the through-thickness stress distribution reaches a maximum in the central cross-section, while at the buildup ends the stresses are distributed almost uniformly. The components of the principal stresses are tensile at the buildup ends near the substrate. Furthermore, the calculated equivalent plastic strain reaches 5.9% near the buildup end, where the deposited layers are completed, while the plastic strain is practically equal to the experimentally measured ductility of the DLD-processed alloy, which is 6.2%. The experimentally measured residual stresses obtained by the force-momentum balance and the plane stress approach differ slightly from each other. KW - Direct laser deposition KW - Finite element simulation KW - Neutron diffraction KW - Residual stresses KW - Ti-6Al-4V KW - Mechanical properties PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542444 DO - https://doi.org/10.3390/ma15010263 VL - 15 IS - 263 SP - 1 EP - 20 PB - MDPI AN - OPUS4-54244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krietsch, Arne A1 - Reyes Rodriguez, M. A1 - Kristen, A. A1 - Kadoke, D. A1 - Abbas, Z. A1 - Krause, U. T1 - Ignition temperatures and flame velocities of metallic nanomaterials N2 - The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powders (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples. T2 - 13th Symposium International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE) CY - Online meeting DA - 27.07.2021 KW - Dust explosions KW - Nanomaterial KW - Flame propagation KW - Minimum ignition temperature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540930 DO - https://doi.org/10.7795/810.20200724 SP - 591 EP - 605 PB - Physikalisch-Technische Bundesanstalt AN - OPUS4-54093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krietsch, Arne A1 - Krause, U. A1 - Gabel, D. A1 - Abbas, Z. A1 - Dufaud, O. T1 - Quasi-static dispersion of dusts for the determination of lower explosion limits of hybrid mixtures N2 - Knowledge of explosion limiting concentration of explosible materials is necessary for the design of explosion protection measures. Currently employed methods of testing MEC of a dust cloud or LEL of a hybrid mixture are based on arbitrary assumptions and possess technical limitations that often lead to values of MEC/LEL, which are unrealistically low or poorly reproducible. This contribution presents an improved method for experimental determination of MEC of a combustible dust cloud or LEL of a flammable gas or hybrid mixture. The new set-up operates under laminar conditions and allows a uniform suspension of dust particles in an open top acrylic glass tube. Dust concentration is measured with the help of infrared sensors installed a few centimeters above and below the ignition source. In order to evaluate the dependence of MEC on flow front velocity, MEC of lycopodium was determined at four flow velocities. The results show that the flow field intensity does not significantly influence the MEC of lycopodium for the flow ranges tested in this work. Moreover, LEL of hybrid mixtures of lycopodium and methane was also tested at flow velocities of 4.7 cm/s, 5.8 cm/s, 7 cm/s and 11 cm/s and compared with the values obtained from other sources. The results suggest that the requirement of high energy pyrotechnical igniter may be relinquished, provided that a truly homogeneous suspension of dust particles could be achieved. Moreover, the effect of relative amount of dust and gas, on the course of ignition and flame propagation in hybrid mixtures at their LEL, was studied by the help of high speed videos. For hybrid mixtures of carbonaceous dusts (like lycopodium) at their LEL, ignition occurs in the gas phase, however, flame propagation is only possible through a two-way interaction of dust and gas during the course of combustion. T2 - 13th Symposium International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE) CY - Online meeting DA - 27.07.2020 KW - Dust explosions KW - Gas explosions KW - Lower explosion limit KW - Hybrid mixtures PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540955 DO - https://doi.org/10.7795/810.20200724 SP - 750 EP - 764 PB - Physikalisch-Technische Bundesanstalt AN - OPUS4-54095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -