TY - JOUR A1 - Nikfalazar, M. A1 - Kohler, C. A1 - Heunisch, Andreas A1 - Wiens, A. A1 - Zheng, Y. A1 - Schulz, Bärbel A1 - Mikolajek, M. A1 - Sohrabi, M. A1 - Rabe, Torsten A1 - Binder, R. A1 - Jakoby, R. T1 - LTCC phase shifters based on tunable ferroelectric composite thick films N2 - This paper presents, the investigation of tunable components based on LTCC technology, implementing ferroelectric tunable thick-film dielectric. The tunable loaded line phase shifters are fabricated with metal-insulator-metal (MIM) varactors to demonstrate the capabilities of this method for packaging of the tunable components. The MIM varactors consist of one tunable dielectric paste layer that is printed between two silver layers. The tunable ferroelectric paste is optimized for LTCC sintering temperature around 850°C. The phase shifters are fabricated in two different process. They were achieved a figure of merit of 24°/dB (phase shift 192°) at 3 GHz and 18°/dB (phase shift 98°) at 4.4 GHz by using seven unit cells that each unit cell consisting of two MIM varactors. KW - Ferroelectric KW - LTCC KW - Phase shifter KW - Fully printed component KW - BST PY - 2015 DO - https://doi.org/10.1515/freq-2015-0082 SN - 0016-1136 SN - 2191-6349 VL - 69 IS - 11-12 SP - 451 EP - 455 PB - De Gruyter CY - Berlin ; Boston, Mass. AN - OPUS4-34949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zinke, R. A1 - Wothe, K. A1 - Dugarev, D. A1 - Götze, O. A1 - Köhler, F. A1 - Schalau, Sebastian A1 - Krause, U. T1 - Uncertainty consideration in CFD-models via response surface modeling: Application on realistic dense and light gas dispersion simulations N2 - Major accidents in the process industry often lead to the release of light or dense gases, which can mean a thread to employees, local residents or to the environment. Possible scenarios are therefore analyzed and evaluated in advance for approval issues. There is a trend, where simple empirical models are being replaced with more complex numerical models. Gaussian dispersion models or models based on dimensional analysis approaches are for example, increasingly replaced by CFD simulations. The main reason for this is the potentially higher accuracy. However, usually scenarios using sharp parameter values are calculated, since comprehensive consideration of parameter distributions via Monte Carlo or Latin Hypercube Sampling fails due to the numerical effort. This includes the risk that the influence of uncertainties on the simulation results is not taken into account. Response surface methods offer an alternative, with which the CFD problem can be mapped onto an algebraic surrogate model. If this is sufficiently precise, parameter sampling can also be carried out with the surrogate as well, as shown in some publications. Previous investigations only demonstrated the basic principle using trivial dispersion models. In this paper two realistic CFD simulations from the plant safety area are considered: VOC emissions from a storage tank and near-ground dense gas emissions. The entire procedure of response surface determination and parameter studies was automated and parallelized for high-performance-computing, and is carried out on the underlying CFD grids. For the CFD simulations as well as for all visualizations, the commercial software ANSYS CFX and the open source software OpenFOAM were used. The aim of this paper is to demonstrate the method using industry-relevant applications as well as to show how this can be used in practical engineering applications. The quality of surrogate modeling, the numerical effort and advantages that can result from the procedure are discussed as well as advantages which may result from taking parameter uncertainties into account in safety studies. KW - CFD KW - Accidental release KW - Response surface methods KW - Air dispersion modeling PY - 2022 DO - https://doi.org/10.1016/j.jlp.2021.104710 SN - 0950-4230 VL - 75 SP - 1 EP - 10 PB - Elsevier CY - Amsterdam AN - OPUS4-56887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohler, C. A1 - Nikfalazar, M. A1 - Heunisch, Andreas A1 - Schulz, Bärbel A1 - Mikolajek, M. A1 - Rabe, Torsten A1 - Jakoby, R. A1 - Binder, J. T1 - Implementation of Ba0.6Sr0.4TiO3-ZnO-B2O3 based tunable microwave phase shifters in LTCC technology N2 - Tunable dielectric Ba0.6Sr0.4TiO3-ZnO-B2O3 thick-films were analyzed regarding their integration potential into the LTCC technology. Therefore, tunable loaded line phase shifters based on metal-insulator-metal varactors with single- and double- printed BST thick-films were fabricated and co-sintered inside a four layer LTCC module. Microstructural and chemical investigations showed a sufficient compatibility and adhesion between the silver, BST composite and LTCC layers and a resulting morphology depending on the processing route. The microwave characterization of the LTCC-embedded phase shifters revealed comparable results to phase shifters with the same design on alumina substrates. KW - Thick films KW - Dielectric materials KW - Electroceramics PY - 2017 DO - https://doi.org/10.1111/ijac.12687 SN - 1546-542X SN - 1744-7402 VL - 14 IS - 4 SP - 574 EP - 582 PB - Wiley CY - Hoboken, NY, USA AN - OPUS4-41086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Modregger, P. A1 - Schäfer, P. A1 - Lübbert, D. A1 - Goebbels, Jürgen A1 - Riesemeier, Heinrich A1 - Köhler, R. T1 - µ-CT with asymmetric Bragg reflection as magnifying optics PY - 2005 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annualreport2004.pdf#page=479 SN - 0179-4159 SP - 479 EP - 480 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-7384 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stühler, Merlin R. A1 - Makki, Hesam A1 - Silbernagl, Dorothee A1 - Dimde, Mathias A1 - Ludwig, Kai A1 - Tegner, Bengt E. A1 - Greve, Christopher A1 - Rausch, Konstantin A1 - Herzig, Eva M. A1 - Köhler, Anna A1 - Plajer, Alex J. T1 - Flexibility and Dynamicity Enhances and Controls Supramolecular Self-Assembly of Zinc(II) Metallogels N2 - Supramolecular self-assembly of stacked architectures is typically achieved through hydrogen bonding or π–π interactions between monomers constructed from stable and inert bonds. In contrast, coordinative interactions of early metals promise distinct self-assembly behaviour due to more flexible bonding geometries and a wider range of stabilities and exchange kinetics. In this report we demonstrate that tailoring the flexible coordination sphere of Zinc(II) complexes via subtle ligand modification promotes not only one but also three-dimensional self-assembly both thermodynamically and kinetically into higher-order fibrous morphologies, the latter being elucidated by electron tomography. As a result, coordination chemistry can be translated into both nanoscopic (fibre stiffness) and macroscopic (thermal gel stability) material properties. Utilizing dynamicity enables gelation via subcomponent self-assembly, constructing the supramolecular polymer network simultaneously with the monomer. Furthermore, coordinative dis- and reassembly via metal-ligand exchange reactions involving the first and second coordination spheres allows for control over gelation and emission of the system. Our report links concepts in supramolecular self-assembly and coordination chemistry by leveraging the unique bonding interactions that cannot be achieved for traditional monomers, promising applications in stimuli-responsive optoelectronics. KW - Nanomaterial KW - AFM KW - Organometallic KW - Gel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634221 DO - https://doi.org/10.1002/adfm.202507793 SN - 1616-301X SP - 1 EP - 10 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-63422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zinke, R. A1 - Virothi, N. A1 - Köhler, F. A1 - Klippel, A. A1 - Schalau, Sebastian A1 - Krause, U. T1 - Experimental measurement of initial evaporation mass flows from gasoline spills and comparison with empirical models N2 - In this paper, we investigate the evaporation mass flow originating from spills of gas-oline. Large spills of gasoline may form during partial or complete roof sinkings or inthe case of perforations at various deck fittings at external floating roof tanks usedfor the storage. Additionally, spills may form in the retention area in the case of leak-ages at pipes or at the hull. The aim is to predict the order of magnitude of real-scaleevaporation mass flow. The determined evaporation mass flows will be used in arelated project as input values for subsequent dispersion modeling in the vicinity ofthe tanks. This is relevant for questions of fire and explosion protection as well as forenvironmental protection aspects in tank farms or refineries, which use externalfloating roof tanks. The measurements presented in this paper were compared withpredictions by empirical models and investigations of evaporations from small floorspills, round-bottom flask, or from Petri dishes published in the literature. The maingoal of this paper is to test the applicability of empirical models to provide reasonableevaporation mass flows as input for CFD dispersion simulations. KW - Spill evaporation PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504322 DO - https://doi.org/10.1002/prs.12128 VL - 39 IS - 3 SP - e12128 PB - Wiley Online Libary AN - OPUS4-50432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strassert, J.F.H. A1 - Köhler, T. A1 - Wienemann, T. H. G. A1 - Ikeda-Ohtsubo, W. A1 - Faivre, N. A1 - Franckenberg, S. A1 - Plarre, Rüdiger A1 - Radek, R. A1 - Brune, A. T1 - 'Candidatus ancillula trichonymphae', a novel lineage of endosymbiotic actinobacteria in termite gut flagellates of the genus trichonympha N2 - Termite gut flagellates are colonized by host-specific lineages of ectosymbiotic and endosymbiotic bacteria. Previous studies have shown that flagellates of the genus Trichonympha may harbour more than one type of symbiont. Using a comprehensive approach that combined cloning of SSU rRNA genes with fluorescence in situ hybridization and electron microscopy, we investigated the phylogeny and subcellular locations of the symbionts in a variety of Trichonympha species from different termites. The flagellates in Trichonympha Cluster I were the only species associated with 'Endomicrobia', which were located in the posterior part of the cell, confirming previous results. Trichonympha species of Cluster II from the termite genus Incisitermes (family Kalotermitidae) lacked 'Endomicrobia' and were associated with endosymbiotic Actinobacteria, which is highly unusual. The endosymbionts, for which we suggest the name 'Candidatus Ancillula trichonymphae', represent a novel, deep-branching lineage in the Micrococcineae that consists exclusively of clones from termite guts. They preferentially colonized the anterior part of the flagellate host and were highly abundant in all species of Trichonympha Cluster II except Trichonympha globulosa. Here, they were outnumbered by a Desulfovibrio species associated with the cytoplasmic lamellae at the anterior cell pole. Such symbionts are present in both Trichonympha clusters, but not in all species. Unlike the intracellular location reported for the Desulfovibrio symbionts of Trichonympha agilis (Cluster I), the Desulfovibrio symbionts of T. globulosa (Cluster II) were situated in deep invaginations of the plasma membrane that were clearly connected to the exterior of the host cell. PY - 2012 DO - https://doi.org/10.1111/1462-2920.12012 SN - 1462-2912 SN - 1462-2920 VL - 14 IS - 12 SP - 3259 EP - 3270 PB - Blackwell Science CY - Oxford AN - OPUS4-27566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Protasov, E A1 - Noah, J O A1 - Kästle Silva, J O A1 - Mies, U S A1 - Hervé, V A1 - Dietrich, C A1 - Lang, K A1 - Mikulski, L A1 - Platt, K A1 - Poehlein, A A1 - Köhler-Ramm, T A1 - Miambi, E A1 - Boga, H I A1 - Feldewert, C A1 - Ngugi, G K A1 - Plarre, Rüdiger A1 - Sillam-Dussès, D A1 - Šobotník, J A1 - Daniel, R A1 - Brune, A T1 - Diversity and taxonomic revision of methanogens and other archaea in the intestinal tract of terrestrial arthropods N2 - Methane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders Methanobacteriales, Methanomassiliicoccales, Methanomicrobiales, and Methanosarcinales, and in a few cases also to nonmethanogenic Nitrososphaerales and Bathyarchaeales. However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed. Full-length 16S rRNA gene sequences and genomes of arthropod-associated archaea are scarce, reference databases lack resolution, and the names of many taxa are either not validly published or under-classified and require revision. Here, we investigated the diversity of archaea in a wide range of methane-emitting arthropods, combining phylogenomic analysis of isolates and metagenome-assembled genomes (MAGs) with amplicon sequencing of full-length 16S rRNA genes. Our results allowed us to describe numerous new species in hitherto undescribed taxa among the orders Methanobacteriales (Methanacia, Methanarmilla, Methanobaculum, Methanobinarius, Methanocatella, Methanoflexus, Methanorudis, and Methanovirga, all gen. nova), Methanomicrobiales (Methanofilum and Methanorbis, both gen. nova), Methanosarcinales (Methanofrustulum and Methanolapillus, both gen. nova), Methanomassiliicoccales (Methanomethylophilaceae fam. nov., Methanarcanum, Methanogranum, Methanomethylophilus, Methanomicula, Methanoplasma, Methanoprimaticola, all gen. nova), and the new family Bathycorpusculaceae (Bathycorpusculum gen. nov.). Reclassification of amplicon libraries from this and previous studies using this new taxonomic framework revealed that arthropods harbor only CO2 and methyl-reducing hydrogenotrophic methanogens. Numerous genus-level lineages appear to be present exclusively in arthropods,suggesting long evolutionary trajectories with their termite, cockroach, and millipede hosts, and a radiation into various microhabitats and ecological nichesprovided by their digestive tracts (e.g., hindgut compartments, gut wall, or anaerobic protists). The distribution patterns among the different host groups are often complex, indicating a mixed mode of transmission and a parallel evolution of invertebrate and vertebrate-associated lineages. KW - Nitrososphaerales KW - Archaea KW - Methanogens KW - Gut microbiota KW - Termites KW - Cockroaches KW - Millipedes KW - Bathyarchaeia PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588230 DO - https://doi.org/10.3389/fmicb.2023.1281628 SN - 1664-302X VL - 14 SP - 1 EP - 21 PB - Frontiers AN - OPUS4-58823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -