TY - JOUR A1 - Fahrbach, M. A1 - Friedrich, Sebastian A1 - Cappella, Brunero A1 - Peiner, Erwin T1 - Calibrating a high-speed contact-resonance profilometer N2 - A European EMPIR project, which aims to use large-scale piezoresistive microprobes for contact resonance applications, a well-established measurement mode of atomic force microscopes (AFMs), is being funded. As the probes used in this project are much larger in size than typical AFM probes some of the simplifications and assumptions made for AFM probes are not applicable. This study presents a guide on how to systematically create a model that replicates the dynamic behavior of microprobes, including air damping, nonlinear sensitivities, and frequency dependencies. The model is then verified by analyzing a series of measurements. KW - Piezoresistive cantilever KW - AFM KW - contact resonance PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509899 DO - https://doi.org/10.5194/jsss-9-179-2020 VL - 9 SP - 179 EP - 187 PB - Copernicus Publications AN - OPUS4-50989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Adham-Zomrawy, A. A1 - Saeed, A. M. A1 - El-Arab, M. A. E. A1 - Shehata, H. A1 - Friedrich, J. T1 - Degradation of organic dye using plasma discharge: optimization, pH and energy N2 - Decolorization of Acid Orange 142 (AO142) as important water pollutant was observed on the exposure of the dye solutions to an atmospheric non-thermal gas plasma. Aresponse Surface methodology (RSM) combined with a central composite design (CCD) was utilized to optimize the main factors (variables) affecting the degradation efficiency (response) of AO142, such as the applied voltage, the gap distance between the high voltage electrode and the surface of the solution. The regression analysis showed that a first-order polynomial model well fits the experimental data with a coefficient of determination R2=0.96. FT-IR, UV-vis,TOCand GC-MS measurements were used to investigate the decolorization of the dye on exposure to the plasma discharges. A possible Degradation pathway was postulated. Additionally, the conductivity and pH changes during the treatment were also evaluated. The plasma treatment combined with Fe2+ (plasma Fenton reaction) exhibited a higher degradation efficiency, higher energy yield connected with lower energy consumption in comparison to the plasma treatment without Fe2+ addition. KW - Advanced Oxidation PY - 2020 DO - https://doi.org/10.1088/2516-1067/ab6703 VL - 2 IS - 1 SP - 015009 PB - IOP publishing Ltd AN - OPUS4-50467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehdianpour, Milad A1 - Waßmuth, Carl-Friedrich T1 - Minimalinvasive Materialuntersuchungen an seilabgespannten Rohrmasten zur Bauwerkserhaltung T1 - Minimally invasive material tests on guyed tubular masts N2 - Abgespannte Stahlrohrmaste zur Rundfunkübertragung wurden in den 1950er- und 60er-Jahren häufig mit Paralleldrahtbündeln errichtet. Diese Seile werden seit geraumer Zeit wegen Korrosionsschäden sukzessive gegen vollverschlossene Spiralseile ausgetauscht. Infolge der damit einhergehenden Veränderung der Steifigkeiten ist mit dem Austausch oft eine Neuberechnung erforderlich. Unter Berücksichtigung der aktuellen Normen können nicht immer alle Nachweise erfüllt werden, selbst wenn das Bauwerk weitgehend noch intakt erscheint. Rohrschaftsanierungen sind extrem aufwändig und können den wirtschaftlichen Totalschaden darstellen, d. h., dem Bauwerk droht Abriss und Neubau. Für die Sanierung des 231 m hohen abgespannten Stahlrohrmastes am Standort Berlin Scholzplatz wurden minimalinvasive Materialuntersuchungen vorgenommen, basierend auf In-situ- und Labortests. In den statistischen Auswertungen konnte belegt werden, dass gegenüber den Angaben der Bauwerksdokumentation höhere Festigkeiten vorlagen. Durch präzise Lastannahmen und für das Bauwerk optimierte Seilvorspannungen konnten aufwändige Verstärkungsmaßnahmen des Rohrschaftes vermieden werden. KW - Bauwerkserhaltung KW - Mast, abgespannter KW - Rohrmast KW - Antennenträger aus Stahl KW - Seile KW - Materialuntersuchung KW - Härtemessung KW - Zugversuch KW - Brinellhärte/Zugfestigkeit KW - Zugfestigkeit/Streckgrenze PY - 2016 UR - http://dx.doi.org/10.1002/bate.201500094 DO - https://doi.org/10.1002/bate.201500094 SN - 1437-0999 VL - 93 IS - 1 SP - 8 EP - 13 PB - Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-35522 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Farag, Zeinab Ramadan A1 - Friedrich, Jörg Florian A1 - Krüger, Simone A1 - Hidde, Gundula A1 - Moustapha, M. E. T1 - Adhesion promotion of thick polyphosphate-poly(allylamine) films onto polyolefin substrates by plasma polymers N2 - The adhesion of thick poly(allylamine)-polyphosphate layers (1 µm) deposited by the wet-chemical layer-by-layer technique (LbL) onto polyethylene or polystyrene (each 100 µm) was very low. To promote the adhesion of these LbL layers the polyolefin substrates were oxidized at the surface by short exposure to the oxygen plasma (2 or 5 s) and subsequently coated with an interlayer of plasma-deposited poly(allylamine) or poly(allyl alcohol) (100 nm). The plasma polymer interlayers have improved strongly the adhesion between polyolefin substrates and polyphosphate coatings. Such phosphate coatings are interesting for life sciences (nucleotide formation) but also for fire retardancy in combination with N-rich compounds such as melamine. The intention was to prefer chemical and hydrogen bonds for adhesion promoting because of their high binding energy. Therefore, the introduced oxygen-containing groups at the polyolefin surface could interact with the OH or NH2 groups of the adhesion-promoting plasma polymer interlayer. These groups were also able to interact strongly with the poly(allylamine)-polyphosphate topcoating. The coated polyolefins were investigated using Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode (FTIR-ATR), X-ray Photoelectron Spectroscopy (XPS), Thermo-Gravimetric Analyses (TGA) and Atomic Force Spectroscopy (AFM) and 90° peel test. KW - Plasma-polymerized poly(allylamine) KW - Adhesion KW - Layer-by-layer deposition KW - Plasma polymerization PY - 2016 UR - http://www.tandfonline.com/doi/abs/10.1080/01694243.2015.1095626 DO - https://doi.org/10.1080/01694243.2015.1095626 SN - 1648-4142 VL - 30 IS - 3 SP - 231 EP - 246 PB - Taylor & Francis AN - OPUS4-35885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, H. J. A1 - Bucheli, T. D. A1 - Dieguez-Alonso, A. A1 - Fabbri, D. A1 - Knicker, H. A1 - Schmidt, H.-P. A1 - Ulbricht, A. A1 - Becker, Roland A1 - Buscaroli, A. A1 - Buerge, D. A1 - Cross, A. A1 - Dickinson, D. A1 - Enders, A. A1 - Esteves, V.I. A1 - Evangelou, M. W. H. A1 - Fellet, G. A1 - Friedrich, K. A1 - Gasco Guerrero, G. A1 - Glaser, B. A1 - Hanke, U. M. A1 - Hanley, K. A1 - Hilber, I. A1 - Kalderis, D. A1 - Leifeld, J. A1 - Masek, O. A1 - Mumme, J. A1 - Paneque Carmona, M. A1 - Calvelo Pereira, R. A1 - Rees, F. A1 - Rombola, A. G. A1 - de la Rosa, J. M. A1 - Sakrabani, R. A1 - Sohi, S. A1 - Soja, G. A1 - Valagussa, M. A1 - Verheijen, F. A1 - Zehetner, F. T1 - Towards the standardization of biochar analysis: the COST action TD1107 interlaboratory comparison N2 - Biochar produced by pyrolysis of organic residues is increasingly used for soil amendment and many other applications. However, analytical methods for its physical and chemical characterization are yet far from being specifically adapted, optimized, and standardized. Therefore, COST Action TD1107 conducted an interlaboratory comparison in which 22 laboratories from 12 countries analyzed three different types of biochar for 38 physical–chemical parameters (macro- and microelements, heavy metals, polycyclic aromatic hydrocarbons, pH, electrical conductivity, and specific surface area) with their preferential methods. The data were evaluated in detail using professional interlaboratory testing software. Whereas intralaboratory repeatability was generally good or at least acceptable, interlaboratory reproducibility was mostly not (20% < mean reproducibility standard deviation < 460%). This paper contributes to better comparability of biochar data published already and provides recommendations to improve and harmonize specific methods for biochar analysis in the future. KW - Biochar KW - Analysis KW - Standardization KW - Ring test KW - Interlaboratory comparison PY - 2016 DO - https://doi.org/10.1021/acs.jafc.5b05055 SN - 0021-8561 SN - 1520-5118 VL - 64 IS - 2 SP - 513 EP - 527 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-35289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dimitriev, O.P. A1 - Grytsenko, K.P. A1 - Lytvyn, P.M. A1 - Doroshenko, T.P. A1 - Briks, J.L. A1 - Tolmachev, A.I. A1 - Slominskii, Y.L. A1 - Kudinova, M.A. A1 - Schrader, S. A1 - Schulze, Rolf-Dieter A1 - Friedrich, Jörg Florian T1 - Substrate-induced self-assembly of donor-acceptor type compounds with terminal thiocarbonyl groups N2 - Two types of conjugated thiocarbonyl-terminated compounds have been synthesized and their ability to be adsorbed on surfaces of the different nature, namely, glass, polytetrafluoroethylene (PTFE), and gold has been studied. Different morphology of the films prepared by thermal vacuum evaporation and drop-casting from solutions has been observed depending on the surface used. It has been found that gold surface has a unique property to influence self-assembly of both monolayer and larger aggregates or crystals of the compounds, in contrast to glass and PTFE substrates. It was found that thiocarbonyl group is able to be chemisorbed to the gold surface. However, it was concluded that in spite of the fact that the thiocarbonyl groups are important for the chemical interaction with the gold surface, physical adsorption on the substrate surface, compound–compound and compound–solvent (when using solution) interactions are of great significance to drive self-assembly of the final film. KW - Thiocarbonyl group KW - Donor–acceptor compound KW - Gold surface KW - Aggregation KW - Film morphology PY - 2013 DO - https://doi.org/10.1016/j.tsf.2013.05.084 SN - 0040-6090 VL - 539 SP - 127 EP - 133 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-30571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ramanujam, Maalolan A1 - Mix, Renate A1 - Wagner, M. A1 - Friedrich, Jörg Florian T1 - Effect of Br gassing after Ar plasma treatment of polyolefins N2 - For simulation and acceleration of artificial polymer ageing, polyolefin foils were exposed to low-pressure Ar plasma. Plasma particle bombardment and irradiation induce C–C and C–H bond scissions by σ→σ* excitations on the surface and in near-surface layers. Consequently, radicals are generated. They react by recombination, cross-linking, metastable trapping of the radical site or formation of olefinic double bonds. The long-living and metastable trapped C-radicals as well as double bonds in polyolefins were immediately exposed to bromine vapour without breaking the vacuum after switching-off the plasma. These reactive sites rapidly react with the molecular bromine under formation of C–Br bonds. For 5 min of argon plasma exposure, the elemental concentration of bromine was 13% for polyethylene and 22% Br/C for polypropylene as analysed by X-ray photoelectron spectroscopy. Nevertheless, not all C radical sites have reacted with bromine. Later on, when the polyolefins brought in contact with ambient air, an additional post-plasma reaction of the remaining trapped radicals with oxygen was observed. The oxygen concentrations were lower after bromine gassing, thus repressing partially the post-plasma oxidation in the analysed layer (ca. 6 nm) by radical quenching. Such bromination took place either at the surface or in near-surface layers because the Attenuated Total Reflectance (ATR)-FTIR spectra (sampling depth ca. 2500 nm) did not show significant changes for argon plasma-treated PE foils with and without bromine vapour exposure. Further addition of bromine may also occur on C=C double bonds. KW - Ageing of polyolefins KW - Argon plasma KW - Radical formation KW - Formation of double bonds PY - 2013 DO - https://doi.org/10.1080/01694243.2012.762326 SN - 0169-4243 SN - 1568-5616 VL - 27 IS - 6 SP - 1828 EP - 1839 PB - VNU Science Press CY - Utrecht AN - OPUS4-30572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Hidde, Gundula A1 - Lippitz, Andreas A1 - Unger, Wolfgang T1 - Plasma bromination of graphene for covalent bonding of organic molecules N2 - Plasma-chemical bromination applied to graphitic materials, in particular to highly ordered pyrolytic graphite is reviewed. The resulting bromination efficiency of the plasma-chemical treatment was subject of systematic process optimization. The plasma of elemental bromine vapour produced bromine concentrations on graphene surfaces of more than 30 % Br/C using either inductively or capacitively coupled low-pressure radio-frequency plasmas. Plasma brominated graphite surfaces have been studied by Near Edge X-ray Absorption Fine Structure, X-ray Photoelectron Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy. The introduction of bromine into graphene-like graphite layers and its binding situation were investigated. To study the physical effect of the plasma bromination process, Kr plasma was also used because of its chemical inertness but similar atomic mass. Covering the samples with a Faraday cage or with a LiF window should help to differentiate between physical, chemical and radiation effects of the plasma. Bromination was assigned to radical or electrophilic addition of bromine onto fully substituted aromatic double bonds (sp² C) with exothermal reaction enthalpy. Low bromination shows a strong decay of aromatic double bonds, higher bromination percentage let disappear all aromatic rings. The formed C–Br bonds were well suited for efficient grafting of organic molecules by post-plasma wet-chemical nucleophilic substitution. This grafting onto the graphene surface was demonstrated using aminosilane and different diamines. The bromination of double bonds changes the hybridization of carbon atoms from plane sp² to tetrahedral sp³ hybridization. Thus, the plane topography of graphene is destroyed and the conductivity is lost. KW - Graphene KW - Bromination KW - Grafting of diamines KW - Plasma KW - Organic graphting PY - 2014 DO - https://doi.org/10.1007/s11090-013-9509-x SN - 0272-4324 VL - 34 SP - 621 EP - 645 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-30575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Friedrich, Jörg Florian ED - Gutowski, W. ED - Dodiuk, H. T1 - Study of metal-polymer interfaces: Relevance to adhesion KW - Polymer surface modification KW - Adhesion KW - Spacer PY - 2013 SN - 978-90-04-20173-6 SN - 978-90-04-20174-3 SP - 3 EP - 33 PB - CRC Press AN - OPUS4-30576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heise, C. A1 - Schedler, U. A1 - Wettmarshausen, Sascha A1 - Friedrich, Jörg Florian T1 - Plasma-brominated cyclo-olefin polymer slides: Suiitable macroinitiators for activator regenerated by electron transfer/atom radical transfer polymerization N2 - Activators regenerated by electron transfer–atom radical transfer polymerization (ATRP) as a controlled living polymerization are distinguished by their acceptance of small amounts of transition-metal complexes and oxygen and by their tolerance of reducing agents at a high concentration. The precondition of all ATRP applications is the use of homolytic or heterolytic cleavable halides as a dormant species; this allows the propagation of monomer chains. Hence, alkyl bromides are slightly cleavable and are the preferred initiators for ATRP. The bromination of polymer slides used as macroinitiators was carried out under gentle bromoform plasma conditions. This led to an oxidation-resistant stable bromine layer. More than 20 bromines per 100 carbons on the polymer scaffold were permanently bound to the substrate after plasma treatment. The resulting amounts of secondary and tertiary bromines on the polymer scaffold exhibited a suitable macroinitiator concentration for the surface-initiated polymerization of methyl methacrylate and glycidyl methacrylate. KW - Copolymers KW - Functionalization of polymers KW - Grafting KW - Monolayers and polymer brushes KW - Radical polymerization PY - 2014 UR - http://onlinelibrary.wiley.com/doi/10.1002/app.40662/full DO - https://doi.org/10.1002/APP.40662 SN - 0021-8995 SN - 1097-4628 VL - 131 IS - 16 SP - 40662-1 EP - 40662-10 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-30577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Sebastian A1 - Cappella, Brunero T1 - Application of contact-resonance AFM methods to polymer samples N2 - Contact-resonance AFM (CR-AFM) has been used in recent years for the measurement of mechanical properties. Compared with other techniques, CR-AFM has a much shorter acquisition time, compensating the incomplete theoretical understanding of the underlying physical phenomena. In the present paper, we propose a procedure, which allows to determine the elastic modulus of the sample as a parameter of the fit of the CR frequency as a function of the load. It is concluded that CR measurements are not appropriate for polymer samples. Major drawbacks are the bad resolution for moduli lower than ca. 10 GPa and the lack of a comprehensive physical model. KW - Atomic force microscopy KW - Contact resonance KW - Mechanical properties KW - Polymers KW - Wear PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515621 DO - https://doi.org/10.3762/bjnano.11.154 VL - 11 SP - 1714 EP - 1727 AN - OPUS4-51562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Saied, M. A. A. A1 - Morgan, N. A1 - Abdelbary, H. A1 - Bahy, S. M. A1 - Schönhals, Andreas A1 - Friedrich, J. F. T1 - Modified polyvinyl chloride membrane grafted with an ultra-thin polystyrene film: structure and electrochemical properties N2 - The work explores the synthesis and the properties of a novel composite membrane System based on modified polystyrene (PS) grafted onto a polyvinyl chloride (PVC) membrane. PVC membranes were prepared by solution-casting followed by exposure to an atmospheric pressure dielectric barrier discharge (DBD) with O2 to obtain an activated Surface for grafting PS to it. Moreover, the thus prepared membranes were chemically modified furthermore by amination with polyethyleneimine or sulfonation with 4 M sulfuric acid. The membrane surface characteristics such as wettability, structure and morphology were investigated using water contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy experiments. The thermogravimetric stability and electrolytic responses of the membranes were studied utilizing TGA, ion exchange capacity (IEC), and solvent uptake. A significant result of plasma and chemical modification was to produce a membrane material with low permeability. Thus, the methanol permeability of the sulfonated membranes measured for 12 h was measured to 2.34$10� 8 cm2 s� 1 compared to 177.00$10� 8 cm2 s� 1 of Nafion 117®which is considered as a benchmark. This result indicates that the prepared sulfonated samples are an innovative and effective material for decreasing the methanol crossover in fuel cells to a great extent. This makes the PVC-g-St membranes are promising and attractive as new materials for polyelectrolyte membrane for fuel cells. KW - Electrolyte membrane KW - Fuell cells PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526794 DO - https://doi.org/10.1016/j.jmrt.2021.04.018 VL - 12 SP - 2273 EP - 2284 PB - Elsevier B.V. AN - OPUS4-52679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - El Sabbagh, M. A1 - Bedair, M. A1 - Gangan, A. A1 - El-Sabbah, M. A1 - El-Bahy, S. A1 - Friedrich, J. T1 - One-step plasma deposited thin SiOxCy films for corrosion resistance of low carbon steel N2 - Tetraethyl orthosilicate (TEOS) was used as a chemical precursor to deposit ultra-thin SiO x C y plasma polymer films onto mild steel surfaces for preventing the corrosion process. The structure–property relationships of the coatings were evaluated by X-ray Photo Spectroscopy (XPS), X-Ray Diffraction (XRD), Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Energy Dispersive X-ray spectroscopy (EDX) completed with Scanning Electron Microscopy (SEM). The SEM micrographs confirmed a pinhole-free surface morphology of the low-pressure deposited plasma polymer films. The TEOS molecules become fragmented in the plasma by numerous collisions with energy-rich electrons and heavier particles. Recombination of fragments and condensation onto the steel substrate is responsible for the formation of organic SiO containing plasma polymer layers. Such thin layers consist of predominantly SiO x structures. Their properties are determined largely by the gap distance between the two samples used as electrodes in the plasma. The efficiency of the corrosion-protecting coating was compared with uncoated samples. The corrosion protection was determined by exposure of samples to 3.5% NaCl aqueous solutions. For this purpose, polarization and Electrochemical Impedance Spectroscopy (EIS) were used to monitor the corrosion. The optimal gap distance between the electrodes was determined for corrosion protection. The best protective efficiency reached more than 97% of the total protection as measured at room temperature. KW - Thin films KW - Corrosion resistance KW - Mild steel KW - Plasma treatments KW - Tetraethyl orthosilicate PY - 2020 DO - https://doi.org/10.1080/01694243.2020.1856539 VL - 35 IS - 16 SP - 1734 EP - 1751 PB - Taylor & Francis AN - OPUS4-52303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahrbach, M. A1 - Friedrich, Sebastian A1 - Behle, H. A1 - Xu, Min A1 - Cappella, Brunero A1 - Brand, U. A1 - Peiner, E. T1 - Customized piezoresistive microprobes for combined imaging of topography and mechanical properties N2 - Customized piezoresistive cantilever microprobes with a deflection range of 120 μm and silicon tips of 100 μm height were operated in a Cypher AFM showing their functionality for measuring topography together with stiffness, adhesion, and viscoelastic properties of thin films. KW - Cantilever microprobe KW - Piezoresistive KW - Atomic force microscopy KW - Force-distance curves KW - Contact resonance KW - Lubricants PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524225 DO - https://doi.org/10.1016/j.measen.2021.100042 VL - 15 SP - 100042 PB - Elsevier Ltd. AN - OPUS4-52422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas A1 - Friedrich, J. T1 - Structure of plasma‐deposited copolymer films preparedfrom acrylic acid and styrene: Part III sulfonation andelectrochemical properties N2 - Acrylic acid-styrene copolymer films were deposited plasma-chemically more gently using the pulsed plasma mode instead of the continuous mode, with linear and some slightly branched chains and marginal crosslinking. Then, the styrene unit of copolymers was wet-chemically sulfonated by chlorosulfuric acid. On exposure to air, the formed 4-chlorosulfonic acid groups hydrolyze to sulfonic acid groups (-SO3H). FTIR, XPS and broadband dielectric spectroscopy were employed to characterize the composition, the structure, the functional groups, and the electrochemical performance for the copolymers. A high concentration of sulfonic acid-containing groups was obtained in the sulfonated PS sample. The values of the DC conductivity DC for the sulfonated sample of the AA/S copolymer are ca. five orders of magnitude higher than that of the not-sulfonated copolymer materials. KW - Plasma Polymers KW - Electrolyte membrane PY - 2022 DO - https://doi.org/10.1002/ppap.202100222 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-54539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Friedrich, Sebastian A1 - Cappella, Brunero T1 - Correction to: Study of micro- and nanoscale wetting properties of lubricants using AFM force-distance curves N2 - The article "Study of micro- and nanoscale wetting properties of lubricants using AFM force-distance Curves" was originally published Online First in the journal "Tribology letters" without Open Access. After publication in volume 68, issue 1, the authors decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Authors 2021 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License. PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542710 DO - https://doi.org/10.1007/s11249-021-01491-1 SN - 1573-2711 VL - 69 SP - 1 PB - Springer CY - Cham AN - OPUS4-54271 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burgmayer, R. A1 - Bake, Friedrich A1 - Enghardt, L. T1 - Design and Evaluation of a Zero Mass Flow Liner N2 - In this study, the concept of a Zero Mass Flow Liner is evaluated. The concept enables impedance control by the induction of periodic bias flow through the perforated facing sheet of the liner. The periodic bias flow is generated by a secondary high amplitude acoustic actuation. By means of the periodic bias flow, the liner can be tuned to different operating points in a given range of grazing flow velocities. The equivalent fluid impedance model for perforated plates is modified to account for the effects of periodic bias flow and grazing flow. An optimization routine, based on a genetic algorithm, is implemented. The method is applicable to any liner concept and uses the impedance of the lined surface as boundary condition in a numerical simulation. Thereby, a set of liner parameters is derived in order to obtain the desired damping characteristics. Based on the results of the optimization, a Zero Mass Flow Liner is manufactured and consequently evaluated experimentally. The damping characteristics are evaluated in form of the dissipated energy along the lined surface. Prediction and measurements show agreement. The Zero Mass Flow Liner delivers broad band dissipation of high peak value over a range of grazing flow Mach numbers. Under grazing ow conditions, the effect of periodic bias flow is reduced. This poses high energy requirements in high Mach number flow regimes which might restrict the applicability of the Zero Mass Flow concept to grazing flows of low Mach numbers. T2 - 28th AIAA/CEAS Aeroacoustics 2022 Conference CY - Southampton, Great Britain DA - 14.06.2022 KW - Acoustic damping KW - Liner KW - Zero Massflow Liner (ZML) PY - 2022 DO - https://doi.org/10.2514/6.2022-2820 SP - 1 EP - 16 PB - AIAA / CEAS AN - OPUS4-55042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirschberg, L. A1 - Bake, Friedrich A1 - Hulshoff, S. T1 - Sound production due to main-flow oriented vorticity-nozzle interaction in absence of a net swirl N2 - The downstream acoustic response due to the interaction of main-flow oriented vorticity with a choked nozzle in a swirl-free flow was experimentally demonstrated. The response was obtained by means of impulsive radial air injection in the pipe upstream from the nozzle. The resulting downstream acoustic data are shown to obey a scaling rule that differs, from the one for swirl-nozzle interaction, which according to the literature is proportional to the square of the swirl number. In contrast, here evidence is presented that points to the scaling of main-flow oriented vorticity noise with the cross-sectional average of the square of the transversal velocity at the throat divided by the square of the critical sound speed. T2 - 28th AIAA/CEAS Aeroacoustics 2022 Conference CY - Southampton, Great Britain DA - 14.06.2022 KW - Main-flow oriented vorticity-nozzle interaction KW - Indirect noise PY - 2022 DO - https://doi.org/10.2514/6.2022-3055 SP - 1 EP - 8 PB - AIAA / CEAS AN - OPUS4-55043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hirschberg, L. A1 - Bake, Friedrich A1 - Knobloch, K. A1 - Hulshoff, S. A1 - Hirschberg, A. T1 - Experimental investigations of indirect noise due to modulation of axial vorticity and entropy upstream of a choked nozzle N2 - An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in the main flow. This eventually induces a large downstream acoustic pulse when tangential injection is interrupted. The magnitude of the resulting sound pulse can reach that of a quasi-steady response of the nozzle to a large air patch with a uniform stagnation temperature equal to that of the upstream-injected heated air. This hypothesis is consistent with the fact that the initial indirect-sound pulse is identical to one obtained with unheated air injection. The authors posit that – given all of the insight gleaned from them in this case – acoustic measurements of indirect sound appear to be a potentially useful diagnostic tool. KW - Aeroacoustics KW - Indirect combustion noise KW - Vorticity noise KW - Entropy noise KW - Swirl PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548331 DO - https://doi.org/10.1016/j.jsv.2022.116989 SN - 0022-460X VL - 532 SP - 1 EP - 22 PB - Elsevier Ltd. AN - OPUS4-54833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Friedrich, J. T1 - Structure of plasma deposited acrylic acid‐allyl alcohol copolymers N2 - Copolymer thin films with two types of functional groups have excellent performance as sensors, for example. The formation and deposition of allyl alcohol‐acrylic acid copolymer films by pulsed high frequency plasma is a complex process. As usual, the chemical composition of the top surface of the films was investigated by XPS and FTIR measurements. Furthermore, contact angle measurements with water were used to characterise the hydrophilicity and wettability of the polymer films. After plasma deposition, a significant decrease in functional groups (OH and COOH) was observed compared to the classically copolymerised equivalent. The remaining functional groups, i.e. the majority of these groups, were sufficient for application as sensor layers. Segmental mobility and conductivity, important for sensor applications, were analysed by broadband dielectric spectroscopy. KW - Plasma Polymerization PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578349 DO - https://doi.org/10.1002/ppap.202300071 SN - 1612-8850 SP - 1 EP - 14 PB - Wiley online library AN - OPUS4-57834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Christian T1 - Eignungsprüfungen geophysikalischer Sensoren zur Rissdetektion an Demonstrationsbauwerken N2 - Bei der Betonage von Abdichtbauwerken können Temperaturen bis 110 °C und hohe Drücke bis 5 MPa erreicht werden. Mittels Technikumsversuchen wurde nachgewiesen, dass Mikroakustik- und Ultraschallsensoren zum Einbau in Demonstrationsbauwerke geeignet sind. Die Untersuchungen wurden bei der BAM (Bundesanstalt für Materialforschung und -prüfung) in Berlin durchgeführt. Es ist vorgesehen, die Sensoren in Morsleben am Demonstrationsbauwerk im Anhydrit einzusetzen. T2 - 84. Jahrestagung der Deutschen Geophysikalischen Gesellschaft CY - Jena, Germany DA - 10.03.2024 KW - Ultraschall KW - Eignungsprüfung KW - Risse KW - Abdichtbauwerk KW - Anhydrit PY - 2024 AN - OPUS4-59772 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Alexander T1 - Simulation of Eddy Current Rail Testing Data for Neural Networks N2 - The present work is part of the AIFRI project (Artificial Intelligence For Rail Inspection), where we and our project partners train a neural network for defect detection and classification. Our goal at BAM is to generate artificial ultrasound and eddy current training data for the A.I. This paper has an exploratory nature, where we focus on the simulation of eddy current signals for head check cracks, one of the most important rail surface defects. The goal of this paper is twofold. On the one hand, we present our general simulation setup. This includes geometric models for head check cracks with features like branching and direction change, a model for the HC10 rail testing probe, and the configuration of the Faraday simulation software. On the other hand, we use the Faraday software to simulate eddy current testing signals with a strong focus on the influence of the damage depth on the signal, while differentiating between different crack geometries. Here, we observe an early saturation effect of the test signal at a damage depth of 2 mm (at a crack angle of 25◦ to the surface). That is about 2 mm earlier than we would expect from measurements at a crack angle of 90◦. This behavior will be investigated further in a future paper. Finally, we interpolate the simulated signals in a two-step curve fitting process. With these interpolations we may generate eddy current test signals for any damage depth within the simulated range. T2 - 13th European Conference on Non-Destructive Testing 2023 CY - Lisbon, Portugal KW - Artificial Intelligence KW - Simulation KW - Eddy Current PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581918 DO - https://doi.org/10.58286/28179 SN - 1435-4934 VL - 28 IS - 8 SP - 1 EP - 6 PB - NDT.net CY - Kirchwald AN - OPUS4-58191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Alexander T1 - Simulation of Eddy Current Rail Testing Data for Neural Networks N2 - The present work is part of the AIFRI project (Artificial Intelligence For Rail Inspection), where we and our project partners train a neural network for defect detection and classification. Our goal at BAM is to generate artificial ultrasound and eddy current training data for the A.I. This paper has an exploratory nature, where we focus on the simulation of eddy current signals for head check cracks, one of the most important rail surface defects. The goal of this paper is twofold. On the one hand, we present our general simulation setup. This includes geometric models for head check cracks with features like branching and direction change, a model for the HC10 rail testing probe, and the configuration of the Faraday simulation software. On the other hand, we use the Faraday software to simulate eddy current testing signals with a strong focus on the influence of the damage depth on the signal, while differentiating between different crack geometries. Here, we observe an early saturation effect of the test signal at a damage depth of 2 mm (at a crack angle of 25◦ to the surface). That is about 2 mm earlier than we would expect from measurements at a crack angle of 90◦. This behavior will be investigated further in a future paper. Finally, we interpolate the simulated signals in a two-step curve fitting process. With these interpolations we may generate eddy current test signals for any damage depth within the simulated range. T2 - 13th European Conference on Non-Destructive Testing 2023 CY - Lisbon, Portugal DA - 03.07.2023 KW - Simulation KW - Eddy Current KW - Artificial Intelligence PY - 2023 AN - OPUS4-58192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Alexander A1 - Zhang, Tianyun T1 - Modellierung von Ultraschall- und Wirbelstromschienenprüfdaten N2 - Im Rahmen des Forschungsprojekts "Artificial Intelligence for Rail Inspection" (AIFRI) wird ein KI-Algorithmus entwickelt, um die Fehlererkennung und Bewertung bei der Auswertung von Schienenprüfungen mittels Ultraschall- und Wirbelstromprüfverfahren zu verbessern. Die Bandbreite möglicher Defekte und die Menge an Einflussgrößen auf die Schienenprüfung ist sehr groß, aber die Prüfdaten aus dem Feld bilden diese Bandbreite nicht balanciert ab und sind unzureichend gelabelt. Durch Simulationen werden große Mengen detailliert gelabelter Daten für relevante Schienenschädigungen und Artefakte bereitgestellt. Aus diesen Daten werden wiederum virtuellen Prüffahrten erstellt, die für das Training und die Validierung der KI genutzt werden können. In unserem Poster stellen wir die Simulation dieser Ultraschall- und Wirbelstromprüfdaten vor. Dabei gehen wir im Detail auf die Themen CAD-Modellierung, Modellparameter, Simulationssoftware und Signalverarbeitung ein. Wir stellen ausgewählt die Simulation von Head Checks für Wirbelstromprüfverfahren und Bohrungsanrissen für Ultraschallprüfverfahren dar, da das Erkennen dieser Schädigungstypen bei der Schienenprüfung hohe Priorität innehat. Für die Verifikation der Simulationsergebnisse verweisen wir auf den ebenfalls eingereichten Vortrag „Verifikation von Ultraschall- und Wirbelstromsimulationen bei der Schienenprüfung“. Das Projekt AIFRI wird im Rahmen der Innovationsinitiative mFUND unter dem Förderkennzeichen 19FS2014 durch das Bundesministerium für Digitales und Verkehr gefördert. T2 - 13. Fachtagung ZfP im Eisenbahnwesen CY - Erfurt, Germany DA - 12.03.2024 KW - Simulation KW - Ultraschall KW - Wirbelstrom PY - 2024 AN - OPUS4-59719 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zhang, Tianyun A1 - Friedrich, Alexander T1 - Verifikation von Ultraschall- und Wirbelstromsimulationen bei der Schienenprüfung N2 - Im Rahmen des Forschungsprojekts "Artificial Intelligence for Rail Inspection" (AIFRI) wird ein KI-Algorithmus entwickelt, um die Fehlererkennung und Bewertung bei der Auswertung von Schienenprüfungen mittels Ultraschall- und Wirbelstromprüfverfahren zu verbessern. Je nach Prüfverfahren werden relevante Schienenschädigungen (z. B. Head Checks) und Artefakte (z. B. Bohrungen) entsprechend analysiert und in einem parametrisierbaren digitalen Zwilling abgebildet, um anschließend die KI-Algorithmen trainieren zu können. Mit der Simulation können Prüffahrten virtuell durchgeführt und Schadensbilder für das KI-Training erzeugt werden, die das Verhalten komplexer Systeme reproduzieren, ohne dass das reale System benötigt wird. Die Modellannahmen sind dabei von erheblicher Bedeutung, denn unzureichende Modellannahmen führen leicht zu falschen Simulationsergebnissen. Um die Ergebnisse einer Simulation ordnungsgemäß darstellen zu können, ist das Simulationsmodell selbst zu überprüfen. Die Vollständigkeit, Richtigkeit und Genauigkeit der Simulationsergebnisse werden anhand von realen Prüfungen verifiziert. Für die Verifikation der Ultraschallsimulation werden hier Stegbohrungen als Referenzreflektoren herangezogen. Als Testkörper stehen Schienensegmente mit unterschiedlichen Profiltypen sowie speziell angefertigte Testkörper mit schienenähnlicher Geometrie zur Verfügung. In den Testkörpern befinden sich künstliche und reale Schädigungen in Kopf-, Steg- und Fußbereich, sowie Bohrungen mit Nuten. Die Validierung der Wirbelstromsimulation erfolgt an Testkörpern, die aus Schienenköpfen gefertigt sind. Dabei werden die Signale für unterschiedliche Nuttiefen und Nutenpaare mit unterschiedlichen Abständen untersucht. Für die Modellierung der Simulationsergebnisse verweisen wir auf das ebenfalls eingereichte Poster „Simulation von Ultraschall- und Wirbelstromprüfdaten für die Schienenprüfung“. Das Projekt AIFRI wird im Rahmen der Innovationsinitiative mFUND unter dem Förderkennzeichen 19FS2014 durch das Bundesministerium für Digitales und Verkehr gefördert. T2 - 13. Fachtagung ZfP im Eisenbahnwesen CY - Erfurt, Germany DA - 12.03.2024 KW - Ultraschallprüfung KW - Simulation KW - Schienenprüfung PY - 2024 AN - OPUS4-59720 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Alexander T1 - The AIFRI Project - Artificial Intelligence For Rail Inspection N2 - The rails of modern railways face an enormous wear and tear from ever increasing train speeds and loads. This necessitates diligent non-destructive testing for defects of the entire railway system. Non-destructive testing of rail tracks is carried out by rail inspection trains equipped with ultrasonic and eddy current test devices. However, the evaluation of the gathered data is mainly done manually with a strong focus on ultrasonic data, and defects are checked on-site using hand-held testing equipment. Maintenance measures are derived based on these on-site findings. The aim of the AIFRI project (Artificial Intelligence For Rail Inspection) is to - increase the degree of automation of the inspection process, from the evaluation of the data to the planning of maintenance measures, - increase the accuracy of defect detection, - automatically classify detected indications into risk classes. These aims will be achieved by training a neural network for defect detection and classification. Since the current testing data is unbalanced, insufficiently labeled and largely unverified we will supplement fused, simulated eddy current and ultrasonic testing data in form of a configurable digital twin. T2 - PostDoc Day 2022 CY - Berlin, Germany DA - 03.11.2022 KW - Non-destructive testing KW - Artificial intelligence KW - Simulation KW - Eddy current KW - Ultrasound PY - 2022 AN - OPUS4-57240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Alexander T1 - AI-based analysis of eddy current and ultrasonic rail testing data N2 - Non-destructive testing of rail tracks is carried out by using rail inspection cars equipped with ultrasonic and eddy current measurement. The evaluation of test data is mainly done manually, supported by a software tool which pre-selects relevant indications shown to the evaluators. The resulting indications have to be checked on-site using hand-held testing equipment. Maintenance interventions are then derived on the basis of these on-site findings. Overall aim of the AIFRI (Artificial Intelligence For Rail Inspection) project - funded by the German Federal Ministry of Digital and Transport (BMDV) as part of the mFUND programme under funding code 19FS2014 – is to increase the degree of automation of the inspection process from the evaluation of the data to the planning of maintenance interventions. The accuracy of defect detection shall be increased by applying AI methods in order to enable an automated classification of detected indications into risk classes. For this purpose, data from both eddy current inspections and ultrasonic inspections will be used in combination. Within the framework of this data-driven project, relevant defect patterns and artefacts present in the rail are analysed and implemented into a configurable digital twin. With the help of this digital twin virtual defects can be generated and used to train AI algorithms for detection and classification. With the help of reliability assessment trained AI algorithms will be evaluated with regard to the resulting quality in defect detection and characterisation. A particular aspect of the development of AI methods is the data fusion of different NDT data sources: Thereby, synergies are used that arise from linking eddy current and ultrasonic inspection data in a combined model. In the course of the project a demonstrator consisting of the developed IT-tool and an asset management system will be implemented and tested in the field using real-world data. T2 - NDT in Railway CY - Berlin, Germany DA - 26.09.2022 KW - NDT KW - Eddy current KW - Ultra sound KW - Simulation KW - Machine learning PY - 2022 UR - https://www.dgzfp.de/seminar/railway/#5 AN - OPUS4-57236 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burgmayer, R. A1 - Bake, Friedrich A1 - Enghardt, L. T1 - Design and Evaluation of a Zero Mass Flow Liner N2 - In this study, the concept of a zero mass flow liner is evaluated. The concept enables impedance control by theinduction of, acoustically actuated, periodic bias flowthrough the facing sheet of the liner. Bymeans of the periodic bias flow, the impedance of the liner is adapted to different grazing flowconditions.The equivalent fluid impedancemodel for perforated plates is modified to account for the effects of periodic bias and grazing flow. A generally applicable optimization routine, using the impedance of the lined surface as a boundary condition in a numeric calculation, is implemented. Based on the results of the optimization, a zero mass flow liner is manufactured and evaluated experimentally. The damping characteristics are assessed in the form of dissipated energy along the lined surface. Prediction and measurements show reasonable agreement. The zero mass flow liner delivers broadband dissipation of high peak value over a range of grazing flow Mach numbers. Under grazing flow, the effect of periodic bias flow is reduced. For a ratio of grazing to bias flow velocities larger than five, no appreciable effect is found. This poses considerable energy requirements on the actuation source for the application in high-Mach-number flow regimes. KW - Zero Massflow Liner KW - Acoustic Damping KW - Liner PY - 2022 DO - https://doi.org/10.2514/1.J062197 SN - 1533-385X SP - 1 EP - 12 PB - AIAA CY - Reston, Va. AN - OPUS4-56410 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Friedrich, Alexander T1 - Simulation data for eddy current rail testing - simulation accuracy and evaluation uncertainty quantification N2 - This dataset serve to quantify the simulation error and the evaluation uncertainties in the context of eddy current rail testing. It was obtained during the AIFRI project (Artificial Intelligence for Rail Inspection) with the Faraday software by INTEGRATED Engineering Software, using its BEM Solver. KW - Non-destructive testing KW - Eddy current testing KW - Eddy current simulstion PY - 2024 DO - https://doi.org/10.5281/zenodo.13970374 PB - Zenodo CY - Geneva AN - OPUS4-61470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kowalski, Kurt A1 - Hulshoff, S.J. A1 - Ströer, P. A1 - Withag, J. A1 - Genot, A. A1 - Morgans, A.S. A1 - Bake, Friedrich A1 - Venner, K. A1 - Sanders, M.P.J. A1 - Hirschberg, Lionel T1 - Entropy-patch choked-nozzle interaction: quasi-steady-modeling-regime limits probed N2 - Indirect combustion noise due to the interaction of flow inhomogeneities with a choked combustion-chamber exit is an important cause of combustion instability in solid rocket motors. Moreover, it is believed to be an issue in electrical-power generation turbines and aero-engines. If these flow inhomogeneities are essentially characterized by the fluid having a locally appreciablydifferent thermodynamic state, the acoustic response engendered by its interaction with the combustion-chamber exit is commonly referred to as entropy noise. In this paper, dedicated numerical-simulation results of entropy-patch choked-nozzle interactions are presented. Two types of entropy patches were considered: rectangular slugs and circular spots. Moreover, analytical-model-based analysis, of said simulation results, is presented. Based on said analysis, the authors posit the existence of three modeling regimes: the quasi-steady-modeling regime, the blended-physical-effects regime, and the inertial-modeling regime. T2 - 30th AIAA/CEAS Aeroacoustics Conference (2024) CY - Rome, Italy DA - 04.06.2024 KW - Entropy-Nozzle Interaction KW - Indirect Combustion Noise KW - Entropy Noise PY - 2024 SN - 978-1-62410-720-7 DO - https://doi.org/10.2514/6.2024-3113 SP - 1 EP - 23 AN - OPUS4-60174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Alexander A1 - Zhang, Tianyun T1 - Simulation von Ultraschall- und Wirbelstromprüfdaten für die Schienenprüfung N2 - Im Rahmen des Forschungsprojekts "Artificial Intelligence for Rail Inspection" (AIFRI) wird ein KI-Algorithmus entwickelt, um die Fehlererkennung und Bewertung bei der Auswertung von Schienenprüfungen mittels Ultraschall- und Wirbelstromprüfverfahren zu verbessern. Die Bandbreite möglicher Defekte und die Menge an Einflussgrößen auf die Schienenprüfung ist sehr groß, aber die Prüfdaten aus dem Feld bilden diese Bandbreite nicht balanciert ab und sind unzureichend gelabelt. Durch Simulationen werden große Mengen detailliert gelabelter Daten für relevante Schienenschädigungen und Artefakte bereitgestellt. Aus diesen Daten werden wiederum virtuellen Prüffahrten erstellt, die für das Training und die Validierung der KI genutzt werden können. In unserem Vortrag stellen wir den Erstellungsprozess der Datensätze vor. Jeder Schritt von der Geometriedarstellung bis zur Datenverarbeitung wird erfasst. Der Fokus wird auf Simulationsergebnisse und deren Verarbeitung gelegt. Die Signalverarbeitung spielt in den Datensätzen eine große Rolle, dabei werden die Datensätze an die realen Daten angepasst. Für Wirbelstrom und Ultraschall werden diese Prozesse im Hinblick auf die Fehlertypen Head Checks und Bohrungsanrisse veranschaulicht. Ferner diskutieren wir die Simulation von Schweißnähten, die von beiden Prüfsystem detektiert werden können; und somit besondere Abstimmung bedürfen aber auch Synergieeffekte zwischen den Prüfsystem ermöglichen. Für die Ablage der Datensätze verweisen wir auf das ebenfalls eingereichte Poster „Verwendung von DICONDE bei der Eisenbahn-Schienenprüfung“. Das Projekt AIFRI wird im Rahmen der Innovationsinitiative mFUND unter dem Förderkennzeichen 19FS2014 durch das Bundesministerium für Digitales und Verkehr gefördert. T2 - DGZfP-Jahrestagung 2024 CY - Osnabrück, Germany DA - 06.05.2024 KW - Wirbelstrom KW - Ultraschall KW - Simulation KW - Machine Learning PY - 2024 AN - OPUS4-60138 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Casperson, Ralf A1 - Friedrich, Alexander A1 - Heckel, Thomas A1 - Zhang, Tianyun T1 - Verwendung von DICONDE bei der Eisenbahn-Schienenprüfung N2 - Bei der zerstörungsfreien Prüfung verlegter Eisenbahnschienen werden die Rohdaten derzeit in proprietären Datenformaten gespeichert und auf Datenträgern zwischen den Prüfzügen und den auswertenden Stellen versendet. Die proprietären Datenformate sind in der Regel nur den Herstellern der Prüfsysteme bekannt und deren Dokumentation nicht allgemein zugänglich. Die „Standard Practice for Digital Imaging and Communication in Nondestructive Evaluation“ (DICONDE), basierend auf dem medizinischen Standard „Digital Imaging and Communication in Medicine“ (DICOM), ermöglicht es, sowohl Prüfdaten als auch Prüfergebnisse und Streckeninformationen in einem standardisierten Format zu speichern und zwischen verschiedenen Endpunkten zu übertragen. Das Poster gibt zunächst einen kurzen Überblick über die hierarchische Struktur von DICONDE und zeigt dann, wie DICONDE bei der Prüfung verlegter Eisenbahnschienen verwendet werden kann. Die geometrischen Besonderheiten (mehrere Kilometer Länge pro Prüffahrt, kurviger Streckenverlauf) stellen dabei eine besondere Herausforderung dar. Im Rahmen des mFUND-geförderten Projektes „Arteficial Intelligence for Railway Inspection (AIFRI)“, Förderkennzeichen 19FS2014C, wurde ein Vorschlag für eine Erweiterung des DICONDE-Standards für die Schienenprüfung erarbeitet und bei der ASTM eingereicht. T2 - DGZfP Jahrestagung 2024 CY - Osnabrück, Germany DA - 05.05.2024 KW - DICONDE KW - Eisenbahn KW - Schienenprüfung PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600204 DO - https://doi.org/10.58286/29500 SP - 1 EP - 5 PB - NDT.net AN - OPUS4-60020 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fink, Friedrich T1 - From Bench to Mini – Identification of technical Lignins with NIR N2 - One of the most underutilized biological materials on our planet is lignin. It is the second most abundant biopolymer after cellulose. On an industrial scale, it mainly accumulates as a by-product in the pulp and paper industry. However, the utilization of technical lignins faces several challenges, including their complex and heterogeneous structure, which makes them difficult to process and limits their application. Additionally, the feedstock origin is a limiting factor. Classification according to the biomass origin is important for quality assurance and predictability of potential applications. In this study, technical lignins were analyzed using a near-infrared (NIR) spectrometer. Different models were developed to classify these lignins, enabling rapid and reliable identification of their biomass sources, including softwoods, hardwoods, straw, and grasses. Various machine learning algorithms such as Support Vector Machines (SVM), Gaussian Process Classification (GPC), Gaussian Naive Bayes (GNB), and Decision Tree Classification (DTC) were compared based on different spectral preprocessing techniques and dimensionality reduction tools. The efficacy of the method was further tested using combined spectra from small handheld and compact spectrometers. T2 - ESOPS 2024 CY - Berlin, Germany DA - 09.09.2024 KW - NIR KW - Lignin PY - 2024 AN - OPUS4-62275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natte, Kishore A1 - Friedrich, Jörg Florian A1 - Wohlrab, Sebastian A1 - Lutzki, J. A1 - von Klitzing, R. A1 - Österle, Werner A1 - Orts-Gil, Guillermo T1 - Impact of polymer shell on the formation and time evolution of nanoparticle-protein corona N2 - The study of protein corona formation on nanoparticles (NPs) represents an actual main issue in colloidal, biomedical and toxicological sciences. However, little is known about the influence of polymer shells on the formation and time evolution of protein corona onto functionalized NPs. Therefore, silicapoly(ethylene glycol) core–shell nanohybrids (SNPs@PEG) with different polymer molecular weights (MW) were synthesized and exhaustively characterized. Bovine serum albumin (BSA) at different concentrations (0.1–6 wt%) was used as model protein to study protein corona formation and time evolution. For pristine SNPs and SNPs@PEG (MW = 350 g/mol), zeta potential at different incubation times show a dynamical evolution of the nanoparticle–protein corona. Oppositely, for SNPs@PEG with MW ≥2000 g/mol a significant suppression of corona formation and time evolution was observed. Furthermore, AFM investigations suggest a different orientation (side-chain or perpendicular) and Penetration depth of BSA toward PEGylated surfaces depending on the polymer length which may explain differences in protein corona evolution. KW - Nanoparticles KW - Silica KW - PEGylation KW - Protein corona KW - BSA KW - Biointerface PY - 2013 DO - https://doi.org/10.1016/j.colsurfb.2012.11.019 SN - 0927-7765 VL - 104 SP - 213 EP - 220 PB - Elsevier AN - OPUS4-38547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natte, Kishore A1 - Österle, Werner A1 - Friedrich, Jörg Florian A1 - von Klitzing, R. A1 - Orts-Gil, Guillermo T1 - Tuning interfacial properties and colloidal behavior of hybrid nanoparticles by controlling the polymer precursor N2 - A facile and versatile synthetic route for controlling the size and surface potential of organic–inorganic hybrid silica nanoparticles (NPs) is introduced in this paper. For polymer-grafted NPs, the density of polymer chains on the surface is strongly affected by the concentration of precursor. Nevertheless, for condensed NPs, the precursor concentration determines the particle size but not the density of polymer chains on the surface or the adsorption of bovine serum albumin (BSA). Results presented here may have Major implications in biomedical and colloidal chemistry since interfacial and colloidal properties are known to drive several processes associated with nanoparticles in biological media. KW - BSA KW - Bio-interface KW - Nanosilica hybrids KW - PEG KW - Protein corona PY - 2012 DO - https://doi.org/10.1002/macp.201200148 SN - 0025-116X SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2412 EP - 2419 PB - Whiley-VCH CY - Weinheim AN - OPUS4-38549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über innere und äußere Ballistik - Messung und Berechnung des Gasdruckes bei Jagdbüchsen PY - 1930 SN - 0368-1785 VL - VIII SP - 214 EP - 220 PB - Verl. Chemie CY - Berlin AN - OPUS4-42933 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über innere und äußere Ballistik - Weitere ballistische Untersuchungen PY - 1930 SN - 0368-1785 VL - VIII SP - 220 EP - 222 PB - Verl. Chemie CY - Berlin AN - OPUS4-42934 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Explosionen - Über die Messung des Druckes der bei Explosionen entstehenden Luftstoßwelle PY - 1930 SN - 0368-1785 VL - VIII SP - 222 EP - 226 PB - Verl. Chemie CY - Berlin AN - OPUS4-42938 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Verschiedenes PY - 1930 SN - 0368-1785 VL - VIII SP - 226 EP - 226 PB - Verl. Chemie CY - Berlin AN - OPUS4-42945 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Explosionsgefahren bei der Lagerung, Beförderung und Verwendung brennbarer Flüssigkeiten - Gefahren der elektrischen Erregung brennbarer Flüssigkeiten PY - 1935 SN - 0368-1785 VL - XIV SP - 369 EP - 371 PB - Verl. Chemie CY - Berlin AN - OPUS4-44326 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Explosionsgefahren bei der Lagerung, Beförderung und Verwendung brennbarer Flüssigkeiten - Brand in der Äther-Betriebsanlage Niederstriegis der Byk-Guldenwerke, Chemische Fabrik A.-G., Berlin PY - 1935 SN - 0368-1785 VL - XIV SP - 371 EP - 372 PB - Verl. Chemie CY - Berlin AN - OPUS4-44328 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Explosionsgefahren bei der Lagerung, Beförderung und Verwendung brennbarer Flüssigkeiten - Brand in der Äther-Betriebsanlage Niederstriegis der Byk-Guldenwerke, Chemische Fabrik A.-G., Berlin - Erhöhung der Sicherheit gegen die Entzündung von Äther durch elektrische Funken bei der Abfülleinrichtung PY - 1935 SN - 0368-1785 VL - XIV SP - 372 EP - 372 PB - Verl. Chemie CY - Berlin AN - OPUS4-44329 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Explosionsgefahren bei der Lagerung, Beförderung und Verwendung brennbarer Flüssigkeiten - Brand in der Äther-Betriebsanlage Niederstriegis der Byk-Guldenwerke, Chemische Fabrik A.-G., Berlin - Bauliche Maßnahmen zur Lokalisierung entstehender Brände PY - 1935 SN - 0368-1785 VL - XIV SP - 372 EP - 372 PB - Verl. Chemie CY - Berlin AN - OPUS4-44350 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über Staubexplosionen - Über Staubexplosionen und ihre experimentelle Untersuchung mit besonderer Berücksichtigung des Aluminiumstaubes PY - 1935 SN - 0368-1785 VL - XIV SP - 372 EP - 381 PB - Verl. Chemie CY - Berlin AN - OPUS4-44351 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über Staubexplosionen - Bekämpfung der Brand- und Explosionsgefahren und ihrer Auswirkungen in Aluminiumstaubfabriken PY - 1935 SN - 0368-1785 VL - XIV SP - 381 EP - 384 PB - Verl. Chemie CY - Berlin AN - OPUS4-44352 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über Staubexplosionen - Eigenschaften von Aluminiumsiliziumsulfid- und Zirkonstaub und die Gefahren bei ihrer Herstellung und Verwendung PY - 1935 SN - 0368-1785 VL - XIV SP - 384 EP - 388 PB - Verl. Chemie CY - Berlin AN - OPUS4-44353 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Sprengungen und Explosionen - Die Bestimmung des Druckes in den beim Sprengen und Schießen entstehenden Luftstoßwellen PY - 1935 SN - 0368-1785 VL - XIV SP - 388 EP - 394 PB - Verl. Chemie CY - Berlin AN - OPUS4-44354 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Sprengungen und Explosionen - Die Wirkung der bei der Detonation von abgeworfenen Sprengbomben entstehenden Luftstoßwellen auf Starkstrom-Freileitungen PY - 1935 SN - 0368-1785 VL - XIV SP - 394 EP - 395 PB - Verl. Chemie CY - Berlin AN - OPUS4-44356 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über innere und äußere Ballistik - Zur praktischen inneren Ballistik PY - 1935 SN - 0368-1785 VL - XIV SP - 342 EP - 345 PB - Verl. Chemie CY - Berlin AN - OPUS4-44294 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Sprengungen und Explosionen - Die Wirkung der bei der Detonation einer Mine entstehenden Luftstoßwelle auf die Zündung benachbarter Minen PY - 1935 SN - 0368-1785 VL - XIV SP - 395 EP - 398 PB - Verl. Chemie CY - Berlin AN - OPUS4-44362 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Sprengungen und Explosionen - Verwendung von Knallgasexplosionen zur Fliegerbekämpfung PY - 1935 SN - 0368-1785 VL - XIV SP - 398 EP - 402 PB - Verl. Chemie CY - Berlin AN - OPUS4-44363 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, Franz A1 - Bollé, Erwin A1 - Finger, A1 - Fricke, Karl A1 - Berg, Friedrich vom A1 - Schneider, Wilhelm A1 - Gliwitzky, T1 - Arbeiten über die Fernwirkung von Sprengungen und Explosionen - Verschiedenes PY - 1935 SN - 0368-1785 VL - XIV SP - 402 EP - 404 PB - Verl. Chemie CY - Berlin AN - OPUS4-44364 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -