TY - JOUR A1 - Welter, T. A1 - Marzok, Ulrich A1 - Deubener, J. A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Hydrogen diffusivity in sodium aluminosilicate glasses N2 - Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartzalbite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized). Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4×10−12 to 3×10−14m2 s−1 (Qz-Np) and from 4×10−13 to 3×10−15m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of Magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend. KW - Aluminosilicate glasses KW - Hydrogen diffusivity KW - Ionic porosity PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119502 VL - 521 SP - 119502 PB - Elsevier B.V. AN - OPUS4-50392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, I. A1 - Moll, J. A1 - Kexel, C. A1 - Schubert, L. A1 - Tschöke, K. A1 - Prager, Jens A1 - Lugovtsova, Yevgeniya A1 - Bach, M. A1 - Vogt, T. T1 - SHM using Guided Waves – Recent Activities and Advances in Germany N2 - Issues that prevent Structural Health Monitoring (SHM) based on Guided Waves (GW) from being a part of today’s monitoring solutions in industry are not all obvious to the scientific community. To uncover and overcome these issues, scientists working on SHM and GW problems joined in an expert committee under the patronage of the German Society for Non-Destructive Testing. An initiated online survey among more than 700 experts and users reveals the hurdles hindering the practical application of GWbased SHM. Firstly, methods for proof of reliability of SHM approaches are missing. Secondly, detailed understanding of phenomenological described wave-damage interactions is needed. Additionally, there are significant unsolved implementation issues and unsolved problems of signal processing including handling of environmental influences. To enable substantial proof of reliability without unaffordable experimental effort also efficient simulation tools including realistic damage interaction are needed, enabling the joint use of experimental and simulated data to predict the capabilities of the Monitoring system. Considering these issues, the committee focusses on simulation, signal processing, as well as probability of detection and standardization. In the presented work, recent activities of the expert committee starting with survey results are summarized. An open access data basis of life-like measurements is presented to allow testing and comparison of signal processing and simulation algorithms. Finally, a strategy for efficient proof of reliability increasing the acceptance of SHM in industry and for successful Integration of SHM into real-world engineering structures is proposed. T2 - The 12th International Workshop on Structural Health Monitoring (IWSHM) CY - Stanford, California, USA DA - 10.09.2019 KW - Structural Health Monitoring KW - Ultrasonic Guided Waves KW - Non-Destructive Testing KW - Survey KW - Probability of Detection KW - Reliability PY - 2019 SP - 1 EP - 10 AN - OPUS4-49232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zoёga, Andreas A1 - Kurz, J. H. A1 - Oelschlägel, T. A1 - Rohrschneider, A. A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Hintze, H. A1 - Kanzler, D. T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn N2 - Currently at Deutsche Bahn (DB) ultrasonic inspections in maintenance procedures for wheelset axles with a bore hole are, to the greatest possible extent, carried out using automated ultrasonic inspection system. Although the acceptance levels are in accordance with DIN 27201 part 7, the testing results have shown in recent years that in the case of true indications, the effective defect sizes were far below the level of acceptance. Due to this experience it can be assumed that the automated ultrasonic inspection systems are testing substantially more sensitively than required. This increased sensitivity leads to an increase in false indications, generally resulting in the unnecessary demounting of wheelsets. In Research cooperation between Federal Institute for Materials Research and Testing (BAM) and DB the effective flaw detection sensitivity of existing automated ultrasonic inspection system will be determined and the true/false indication ratio optimised. Through systematic investigations with the Probability of Detection method on the existing automated ultrasonic inspection system the results could be directly applied to the optimisation of existing ultrasonic inspections of wheelset axles with a bore hole in maintenance procedures and the level of reliability can be considerably increased. T2 - 19th World Conference on Non-Destructive Testing CY - München, Germany DA - 13.06.2016 KW - NDT KW - Reliability KW - POD KW - Railway KW - Axles KW - UT PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375813 UR - http://www.ndt.net/article/wcndt2016/papers/we2g4.pdf SP - id 19515, 1 EP - 8 AN - OPUS4-37581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Buckle, T. A1 - van der Wal, S. A1 - van Malderen, S. A1 - Müller, Larissa A1 - Kuil, J. A1 - van Unen, V. A1 - Peters, R. A1 - van Bemmel, M. A1 - McDonnell, L. A1 - Velders, A. A1 - Koning, F. A1 - Vanhaeke, F. A1 - van Leeuwen, F. T1 - Hybrid imaging labels: providing the link between mass spectrometry-based molecular pathology and theranostics N2 - Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for in vitro and in vivo evaluation; e.g. fluorescence or nuclear medicine. In this study a bimodal (or rather, hybrid) tracer that contains both a fluorescent dye and a chelate was used to evaluate the existence of a direct link between mass spectrometry (MS) and in vitro and in vivo molecular imaging findings using fluorescence and radioisotopes. At the same time, the hybrid label was used to determine whether the use of a single isotope label would allow for MS-based diagnostics. KW - Imaging KW - Laser Ablation ICP-MS KW - Diagnostics PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396813 DO - https://doi.org/10.7150/thno.17484 VL - 7 IS - 3 SP - 624 EP - 633 PB - IvySpring AN - OPUS4-39681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mühler, T. A1 - Helsch, G. A1 - Heinrich, J.G. A1 - Yao, Dongxu A1 - Gräf, S. A1 - Müller, F.A. A1 - Günster, Jens T1 - Strategies for the selective volume sintering of ceramics N2 - The present study is dealing with the basic physics for a novel way to generate a free-formed ceramic body, not like common layer by layer, but directly by Selective Volume Sintering (SVS) in a compact block of ceramic powder. To penetrate with laser light into the volume of a ceramic powder compact it is necessary to investigate the light scattering properties of ceramic powders. Compared with polymers and metals, ceramic materials are unique as they offer a wide optical window of transparency. The optical window typically ranges from below 0.3 up to 5 µm wave length. In the present study thin layers of quartz glass (SiO2) particles have been prepared. As a function of layer thickness and the particle size, transmission and reflection spectra in a wave length range between 0.5 and 2.5 µm have been recorded. Depending on the respective particle size and by choosing a proper relation between particle size and wave length of the incident laser radiation, it is found that light can penetrate a powder compact up to a depth of a few millimeters. With an adjustment of the light absorption properties of the compact the initiation of sintering in the volume of the compact is possible. KW - Additive Manufacturing PY - 2014 DO - https://doi.org/10.1557/jmr.2014.174 SN - 0884-2914 VL - 29 IS - 17 SP - 2095 EP - 2099 PB - Materials Research Society CY - Warrendale, Pa. AN - OPUS4-32544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wirth, Cynthia A1 - Müller, Ralf A1 - Günster, Jens A1 - Mühler, T. A1 - Görke, R. A1 - Heinrich, J.G. T1 - Submicrometer silica spheres generated by laser fuming N2 - The production of agglomerate-free SiO2 particles exhibiting a monomodal distribution of particle sizes of around 300 nm by means of direct laser fuming of micrometric SiO2 powders has been successfully demonstrated. With a 12 kW cw CO2 laser system, a production rate of up to 1 kilogram powder per hour was achieved. Almost ideal spherical amorphous SiO2 particles in a broad particle size distribution between 10 nm and several 100 nm (d50 ≈ 300 nm) were synthesized. Several observations suggest weak agglomeration forces between the particles. A temperature reduction of 200 °C for sintering powder compacts was observed. KW - Laser KW - SiO2 KW - Nanopowder PY - 2013 DO - https://doi.org/10.4416/JCST2012-00033 SN - 2190-9385 N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M. VL - 4 IS - 1 SP - 11 EP - 18 PB - Göller CY - Baden-Baden AN - OPUS4-31423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, S. E. A1 - Müller, L. A1 - Barrea, R. A1 - Kampf, C.J. A1 - Leiterer, Jork A1 - Panne, Ulrich A1 - Hoffmann, T. A1 - Emmerling, Franziska A1 - Tremel, W. T1 - Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates N2 - During the mineralisation of metal carbonates MCO3 (M = Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed. PY - 2011 DO - https://doi.org/10.1039/c0nr00761g SN - 2040-3364 SN - 2040-3372 IS - 3 SP - 1158 EP - 1165 PB - RSC Publ. CY - Cambridge AN - OPUS4-23355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -