TY - GEN A1 - Budnik, J. A1 - Betz, T. A1 - Brameshuber, W. A1 - Fromm, A. A1 - Gerdes, A. A1 - Gerlach, J. A1 - Götz, M. A1 - Hart, R. A1 - Heese, C. A1 - Hintzen, W. A1 - Hüttl, R. A1 - Kämpfer, W. A1 - König, A. A1 - Kühner, S. A1 - Lohaus, L. A1 - Meng, Birgit A1 - Neumann, T. A1 - Remus, R. A1 - Schaab, A. A1 - Schäffel, P. A1 - Schauerte, J. A1 - Schönborn, A. A1 - Siebert, B. A1 - Stephan, D. A1 - Tebbe, H. A1 - Wagner, J.-P. ED - Siebert, B. T1 - Chemischer Angriff auf Beton - Empfehlungen zur Prüfung und Bewertung N2 - ln den letzten Jahren wurden diverse Prüfverfahren und Methoden entwickelt, um die Leistungsfähigkeit von Beton bzw. Bindemittel hinsichtlich des Widerstands gegenüber betonaggressiven Einwirkungen beurteilen zu können. Ein wesentliches Ziel von Prüfverfahren zur Beurteilung der Dauerhaftigkeit von Baustoffen ist, die im Laufe der Nutzungsdauer zu erwartenden Einwirkungen auf den Baustoff realitätsnah abzubilden. Dazu sind die Prüfparameter auf die im jeweiligen Anwendungsbereich vorherrschenden Umgebungs- und Randbedingungen anzupassen. Daneben sind auch die Bewertungskriterien individuell unter Berücksichtigung der im Einzelfall geforderten Nutzungsdauer eines Bauwerks festzulegen. Eine systematische Zuordnung von adäquaten Prüfverfahren bzw. Prüfparametem und Bewertungskriterien für die verschiedenen Anwendungsbereiche im Betonbau, in denen betonaggressive Einwirkungen auftreten, ist mit Ausnahme von Einzelfällen bislang nicht vorhanden. Daneben stellt sich in der Praxis immer wieder das Problem, das Angriffspotenzial der Umgebung eines Bauwerks (prüftechnisch) zu erfassen und zu bewerten. Der Hauptausschuss Baustofftechnik des DBV hat daher den Arbeitskreis „Chemischer Angriff auf Beton“ beauftragt, dieses Merkblatt zu erarbeiten, das auf Basis von einschlägigen Erfahrungen der Baupraxis und wissenschaftlichen Erkenntnissen Grundsätze und bewährte Methoden zur Beurteilung der Einwirkungs- und Widerstandsseite beim chemischen Angriff auf Beton aufzeigt und diesbezüglich Hinweise für verschiedene Anwendungsbereiche im Betonbau liefert. KW - Beton KW - Betonangriff KW - Dauerhaftigkeit KW - Säureangriff PY - 2017 SP - 1 EP - 65 PB - Eigenverlag Deutscher Beton- und Bautechnik-Verein e. V. CY - Berlin AN - OPUS4-44663 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, R. A1 - Vaishampayan, A. A1 - Cuellar-Camacho, J. L. A1 - Wight, D. J. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang A1 - Grohmann, E. A1 - Haag, R. A1 - Wagner, O. T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies. KW - Surface charge KW - Bacteria KW - Graphene oxide KW - Escherichia coli KW - XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651 DO - https://doi.org/10.1002/admi.201902066 VL - 7 IS - 15 SP - 1902066 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Wagner, G. A1 - Saliwan Neumann, Romeo A1 - Skála, R. A1 - Geist, V. T1 - Investigation of the orientation relationships of carlsbergite in the North Chile iron meteorite KW - Orientation realtionships KW - CrN KW - (Fe,Ni)3P PY - 2005 SN - 1086-9379 SN - 0026-1114 SP - 14 pages PB - Allen Press CY - Lawrence, Kan. AN - OPUS4-7592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Sensorische Mikropartikel aus einem Silicatkern und einem molekular geprägten Polymer als Schale mit aufleuchtender Fluoreszenz N2 - Und es ward Licht – der Einbau eines auf Harnstoff basierenden Fluoreszenzfarbstoffs in eine mit Anionen geprägte dünne Polymerschale (MIP) auf Silicatmikropartikeln führt zu einem spezifischen und enantioselektiven Aufleuchten der Fluoreszenz in Gegenwart des Zielanalyten. KW - Enantioselektivität KW - Fluoreszenz KW - Kern-Schale-Partikel KW - Molekular geprägte Polymere KW - Sensoren PY - 2013 DO - https://doi.org/10.1002/ange.201300322 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 125 IS - 27 SP - 7161 EP - 7165 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28739 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Fluorescent sensorymicroparticles that 'light-up' consisting of a silica core and a molecularly imprinted polymer (MIP) shell N2 - From darkness came light: Incorporation of urea-based fluorescent dyes in an anion-imprinted thin polymer shell coated onto silica microparticles leads to a unique and highly enantioselective fluorescent 'light-up' response to analytes (see scheme, MIP molecularly imprinted polymer). KW - Core–shell particles KW - Enantioselectivity KW - Fluorescence KW - Molecularly imprinted polymers KW - Sensors PY - 2013 DO - https://doi.org/10.1002/anie.201300322 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 52 IS - 27 SP - 7023 EP - 7027 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, R. A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Benito-Pena, E. A1 - Moreno-Bondi, M.C. A1 - Lazraq, I. A1 - Rurack, Knut A1 - Sellergren, B. T1 - Synthesis, spectroscopic, and analyte-responsive behavior of a polymerizable naphthalimide-based carboxylate probe and molecularly imprinted polymers prepared thereof N2 - A naphthalimide-based fluorescent indicator monomer 1 for the integration into chromo- and fluorogenic molecularly imprinted polymers (MIPs) was synthesized and characterized. The monomer was equipped with a urea binding site to respond to carboxylate-containing guests with absorption and fluorescence changes, namely a bathochromic shift in absorption and fluorescence quenching. Detailed spectroscopic analyses of the title compound and various models revealed the signaling mechanism. Titration studies employing benzoate and Z-ʟ-phenylalanine (Z-ʟ-Phe) suggest that indicator monomers such as the title compound undergo a mixture of deprotonation and complex formation in the presence of benzoate but yield hydrogen-bonded complexes, which are desirable for the molecular imprinting process, with weakly basic guests like Z-ʟ-Phe. Compound 1 could be successfully employed in the synthesis of monolithic and thin-film MIPs against Z-ʟ-Phe, Z-L-glutamic acid, and penicillin G. Chromatographic assessment of the selectivity features of the monoliths revealed enantioselective discrimination and clear imprinting effects. Immobilized on glass coverslips, the thin-film MIPs of 1 displayed a clear signaling behavior with a pronounced enantioselective fluorescence quenching dependence and a promising discrimination against cross-analytes. KW - Aminosäuren KW - Enantioselektivität KW - Fluoreszenz KW - Molekular geprägte polymere KW - Sensorfilme PY - 2013 DO - https://doi.org/10.1021/jo3019522 SN - 0022-3263 SN - 1520-6904 VL - 78 IS - 4 SP - 1377 EP - 1389 PB - American Chemical Society CY - Washington, DC AN - OPUS4-27741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Wagner, G. A1 - Saliwan Neumann, Romeo A1 - Skála, R. A1 - Geist, V. T1 - Orientation relationships of carlsbergite in schreibersite and kamacite in the north Chile iron meteorite N2 - The crystallographic orientation of carlsbergite (CrN) in the north Chile meteorite (hexahedrite) was investigated using electron backscatter diffraction and transmission electron microscopy. These studies examined the CrN crystals in the rhabdites (idiomorphic schreibersite) and in kamacite. It was found that the CrN crystals embedded in rhabdite show a number of different orientation relationships with the host crystals. These orientations can be explained based on the lattice dimensions of both coexisting crystalline materials. It was also found that both carlsbergite and kamacite are characterized by a high dislocation density (109 cm–2) while rhabdite is free of dislocations. It is supposed that in spite of the deformed metallic matrix, a general connection between the orientation relation of all the phases involved exists. KW - EBSD KW - Phosphides KW - Carlsbergite KW - Orientation relationship KW - Iron meteorites PY - 2006 DO - https://doi.org/10.1180/0026461067040342 SN - 0026-461x SN - 1471-8022 VL - 70 IS - 4 SP - 373 EP - 382 PB - Mineralogical Society of Great Britain and Ireland CY - London AN - OPUS4-14424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Enantioselective fluorescence response of molecularly imprinted polymers (MIPs) toward carbobenzyloxy- (Cbz) protected amino acids N2 - Integration of a polymerisable fluorescent urea-nitrobenzoxadiazole monomer 1 into a few-nanometre thin molecularly imprinted polymer (MIP) shell coated onto a 300 nm silica core with the tetrabutylammonium salt of N-carbobenzyloxy-L-phenylalanine (Cbz- or Z-ʟ-Phe) as the imprinted template yields core/shell MIP nanoparticles that respond to the designated analyte with a strong fluorescence increase in the visible spectral range. The system shows promising imprinting and enantioselectivity factors of 3.6 and 1.9 when benzylmethylacrylate (BMA) is used as co-monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker. A second, naphthalimide-based fluorescent urea 2 is employed in the preparation of MIP thin-films and monolithic polymers for separation techniques. Spectroscopic and chromatographic studies of the MIPs with the analytes Z-ʟ-Phe, Z-ʟ-glutamic acid (Z-ʟ-Glu) and penicilin G (PenG) revealed the (enantio)selective discrimination behaviour of these materials. T2 - 11. Dresdner Sensor Symposium 2013 CY - Dresden, Germany DA - 09.12.2013 KW - Enantioselectivity KW - Molecular imprinting KW - Fluorescence KW - Core-shell nanoparticles KW - Chromatography PY - 2013 SN - 978-3-9813484-5-3 DO - https://doi.org/10.5162/11dss2013/3.2 SP - 53 EP - 58 CY - Wunstorf AN - OPUS4-29818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arinchtein, A. A1 - Ye, M.-Y. A1 - Yang, Q. A1 - Kreyenschulte, C. A1 - Wagner, Andreas A1 - Frisch, M. A1 - Brückner, A. A1 - Kondratenko, E. A1 - Kraehnert, R. T1 - Dynamics of Reaction-Induced Changes of Model-Type Iron Oxide Phases in the CO2-Fischer-Tropsch-Synthesis N2 - Iron-based catalysts are employed in CO2-FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2-FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2-FTS atmospheres at 20 bar and 300°C. Up to three distinct phases were observed depending on the timeon-stream (TOS): a sintered maghemite/magnetite phase, a carbidic core-shell structure, and a low-crystalline, needle-type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase. Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed. KW - Nanostructured FeOx films KW - CO2 KW - Scanning Auger Spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549709 DO - https://doi.org/10.1002/cctc.202200240 SN - 1867-3880 VL - 14 IS - 14 SP - 1 EP - 11 PB - Wiley-VCH AN - OPUS4-54970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wurzler, Nina A1 - Schütter, Jan David A1 - Wagner, R. A1 - Dimper, Matthias A1 - Hodoroaba, Vasile-Dan A1 - Lützenkirchen-Hecht, D. A1 - Özcan Sandikcioglu, Özlem T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part II: Effect on biofilm formation and microbially influenced corrosion processes N2 - Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion. KW - Biofilms KW - XANES KW - Microbially influenced corrosion (MIC) PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528130 DO - https://doi.org/10.1002/maco.202012192 VL - 72 IS - 6 SP - 983 EP - 994 PB - Wiley AN - OPUS4-52813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -