TY - JOUR A1 - Menzel, Michael A1 - Uzoukwu, B. A. A1 - Gloe, K. A1 - Wawrzyniak, K. T1 - Syntheses and 119Sn Mössbauer spectral characterization of tin(IV) complexes of 4-acyl-1-phenyl-3-methylpyrazolones-5 and molecular modelling of 4-acetyl-1-phenyl-3-methylpyrazolone-5 PY - 2004 SN - 0019-5103 VL - 43 SP - 701 EP - 705 PB - Pergamon Press CY - Oxford AN - OPUS4-908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehner, Hartmut A1 - Menzel, Michael A1 - Weber, K. A1 - Regener, D. T1 - Characterization of the microstructure of high-chromium cast irons using Mössbauer spectroscopy N2 - The finish grinding process for cement materials uses ball mills with differently sized grinding balls. Because the grinding takes place through the impact and friction of the balls, balls with a high wear resistance are desirable and the materials of choice are the high-chromium white cast irons. This article examines the behavior of these cast irons when subjected to various heat treatments. The emphasis is on the dependence of the microstructure properties on the chemical composition of the alloys and the heat treatment parameters. The content of retained austenite and that of carbon in the martensite phase were determined by the use of Mössbauer spectroscopy. The results verify that a higher proportion of retained austenite with low carbon content and a martensite with higher hardness produce a material with good fracture toughness and resistance to abrasive wear. KW - High-cromium cast irons KW - White cast irons KW - Grinding process of cement materials KW - Grinding balls KW - As-cast grinding balls PY - 2001 DO - https://doi.org/10.1016/S1044-5803(01)00143-7 SN - 1044-5803 SN - 1873-4189 VL - 46 SP - 399 EP - 406 PB - Elsevier CY - New York, NY AN - OPUS4-1205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, Michael A1 - Uzoukwu, B.A. A1 - Gloe, K. A1 - Rademacher, O. T1 - Synthesis, Spectroscopic, and X-Ray Diffraction Studies of cis-Dichlorobis(4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-onato) Tin(IV) N2 - Reaction between an aqueous ethanol solution of tin(II) chloride and that of 4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3 H-pyrazol-3-one in the presence of O2 gave the compound cis-dichlorobis(4-propanoyl-2,4-dihydro-5-methyl-2-phenyl-3 H-pyrazol-3-onato) tin(IV) [(C26H26N4O4)SnCl2]. The compound has a six-coordinated SnIV centre in a distorted octahedral configuration with two chloro ligands in cis position. The tin atom is also at a pseudo two-fold axis of inversion for both the ligand anions and the two cis-chloro ligands. The orange compound crystallizes in the triclinic space group P 1 with unit cell dimensions, a = 8.741(3) Å, b = 12.325(7) Å, c = 13.922(7) Å; = 71.59(4), = 79.39(3), = 75.18(4); Z = 2 and Dx = 1.575 g cm-3. The important bond distances in the chelate ring are Sn-O [2.041 to 2.103 Å], Sn-Cl [2.347 to 2.351 Å], C-O [1.261 to 1.289 Å] and C-C [1.401 Å] the bond angles are O-Sn-O 82.6 to 87.7° and Cl-Sn-Cl 97.59°. The UV, IR, 1H NMR and 119Sn Mössbauer spectral data of the compound are reported and discussed. KW - Tin (IV) complex KW - 4-Acyl-pyrazolone KW - Spectroscopy KW - Crystal structure PY - 2001 DO - https://doi.org/10.1002/1521-3749(200101)627:1<103::AID-ZAAC103>3.0.CO;2-5 SN - 0044-2313 SN - 1521-3749 SN - 0372-7874 SN - 0863-1786 SN - 0863-1778 IS - 627 SP - 103 EP - 107 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stößer, R. A1 - Feist, M. A1 - Patzwaldt, K. A1 - Menzel, Michael A1 - Emmerling, Franziska ED - Brooks, H. T1 - Redox reactions of K3[Fe(CN)6] during mechanochemically stimulated phase transitions of AlOOH N2 - Thermally induced redox reactions of K3[Fe(CN)6] (1) were investigated for a broad temperature range by thermal methods and structure analytical methods (ESR and Mößbauer spectroscopy, X-ray Powder diffraction and XANES). Based on the influence of the mechanically activated and transforming matrices 2 and 3, redox processes can be tuned to form doped Al2O3 systems which contain either isolated Fe3+ centres or redox active phases and precursors like (Al1-xFex)2O3 (4), (Al3-xFex)O4 (5), Fe3O4, Fe2O3 and Fe0. The phase Fe3C and the chemically reactive C-species were detected during the reaction of 1. The final composition of the doped products of α-Al2O3 is mainly influenced by the chemical nature of the Fe doping component, the applied temperature and time regime, and the composition of the gas phase (N2, N2/O2 or N2/H2). From the solid state chemistry point of view it is interesting that the transforming matrix (2 and 3) possesses both oxidative and protective properties and that the incorporation of the Fe species can be performed systematically. KW - A. Inorganic compounds KW - C. Mössbauer spectroscopy KW - C. Thermogravimetric analysis KW - D. Electron paramagnetic resonance KW - ESR-Spektroskopie KW - Kaliumhexacyanoferrat(III) KW - Mechanische Aktivierung KW - Mößbauer-Spektroskopie KW - Redoxreaktionen KW - TA-MS-Messungen PY - 2011 DO - https://doi.org/10.1016/j.jpcs.2011.03.016 SN - 0022-3697 VL - 72 IS - 6 SP - 794 EP - 799 PB - Pergamon Press CY - New York, NY AN - OPUS4-23685 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, Friederike A1 - Conradi, Bianca A1 - Rodenacker, K. A1 - Gorbushina, Anna A1 - Schwibbert, Karin ED - Menzel, Friederike T1 - Flow chamber system for the statistical evaluation of bacterial colonization on materials N2 - Biofilm formation on materials leads to high costs in industrial processes, as well as in medical applications. This fact has stimulated interest in the development of new materials with improved surfaces to reduce bacterial colonization. Standardized tests relying on statistical evidence are indispensable to evaluate the quality and safety of these new materials. We describe here a flow chamber system for biofilm cultivation under controlled conditions with a total capacity for testing up to 32 samples in parallel. In order to quantify the surface colonization, bacterial cells were DAPI (4‘,6-diamidino-2-phenylindole)-stained and examined with epifluorescence microscopy. More than 100 images of each sample were automatically taken and the surface coverage was estimated using the free open source software g’mic, followed by a precise statistical evaluation. Overview images of all gathered pictures were generated to dissect the colonization characteristics of the selected model organism Escherichia coli W3310 on different materials (glass and implant steel). With our approach, differences in bacterial colonization on different materials can be quantified in a statistically validated manner. This reliable test procedure will support the design of improved materials for medical, industrial, and environmental (subaquatic or subaerial) applications. KW - Subaerial and subaquatic biofilm KW - Escherichia coli KW - Image analysis KW - Microscopy KW - Biofilm KW - Biofouling PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377040 DO - https://doi.org/10.3390/ma9090770 SN - 1996-1944 VL - 9 IS - 9 SP - 770 AN - OPUS4-37704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Raupach, M. A1 - Mietz, Jürgen A1 - Nürnberger, U. A1 - Wolff, L. A1 - Bruns, M. A1 - Burkert, Andreas A1 - Eich, Gerd A1 - Menzel, K. T1 - Entwicklung eines kombinierten Schutzsystems für chloridbelastete Betonflächen aus Spritzverzinkung mit abdichtender Beschichtung (Abschlussbericht, AiF 12 818 N/2) N2 - Die Zielsetzung dieses Projektes war es, ein kombiniertes Schutzsystem aus Spritzverzinkung und abdichtendem Oberflächenschutzsystem für die Instandsetzung chloridbelasteter und korrosionsgeschädigter Stahlbetonbauteile zu entwickeln. Dabei soll die Spritzverzinkung der Betonoberfläche in den ersten Jahren nach der Instandsetzung einen kathodischen Korrosionsschutz der Bewehrung bewirken, bis der Beton infolge des Oberflächenschutzsystems soweit ausgetrocknet ist, dass auch ohne kathodischen Schutz praktisch keine Korrosion der Bewehrung mehr stattfinden kann. Anhand von Untersuchungen zur Haftung zwischen Beton, Zinkschicht und verschiedenen Oberflächenschutzsystemen wurde der Aufbau des kombinierten Schutzsystems entwickelt. Es wurden verschiedene OS-11a-Systeme ein OS-13-System sowie zwei Systeme nach ZTV-ING, Teil 7 vor und nach künstlicher Bewitterung untersucht. Anhand der Ergebnisse wurde für das kombinierte System ein OS-11a-System ausgewählt und im weiteren hinsichtlich der Wirksamkeit des kathodischen Schutzes sowie hinsichtlich der Austrocknung des Betons untersucht. Es zeigte sich sowohl an ausgelagerten Prüfköpfen sowie auf einer angelegten Versuchsfläche auf Freideck eines Parkhauses, dass ein wirksamer galvanischer kathodischer Korrosionsschutz der Bewehrung nur bei sehr hohen Chloridgehalten (4 M.-% bezogen auf den Zementgehalt) erreicht werden kann. Bei geringeren untersuchten Chloridgehalten kam es vermutlich infolge der Austrocknung der Zink/Beton-Kontaktzone nach relativ kurzer Zeit zu einer Inaktivierung des Zinks. Bei Chloridgehalten von 4 M.-% bildeten sich zwischen der Zinkschicht und dem ausgewählten OS-System gasgefüllte Blasen. Diese Problematik, sowie die Tatsache dass die Wirksamkeit des Prinzips W (Austrocknung des Betons) bei derart hohen Chloridgehalten bezweifelt werden muss, grenzt die Anwendbarkeit des Kombinationssystems mit der Zinkschicht als Opferanode deutlich ein. An neun Jahre alten, ausgelagerten Prüfköpfen durchgeführte Untersuchungen zeigten jedoch, dass mittels Fremdstrombeaufschlagung zwischen Zinkschicht und Bewehrung ein wirksamer kathodischer Schutz auch bei geringeren Chloridgehalten erreicht werden kann. Der Einsatz des entwickelten Kombinationssystems mit Fremdstrombeaufschlagung erscheint somit durchaus durchführbar. Dabei sollte der Fremdstrom jedoch vorsichtig dosiert werden, um den Haftverbund zum Zink nicht zu sehr zu schwächen. Das Ziel des Vorhabens wurde somit erreicht. KW - Chlorinduzierte Korrosion KW - Kathodischer Korrosionsschutz KW - Oberflächenschutzsystem KW - Stahlbeton KW - Thermische Spritzverzinkung PY - 2004 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355176 SP - 1 EP - 122 PB - IBAC Institut für Bauforschung CY - Aachen AN - OPUS4-35517 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolb, U. A1 - Büscher, K. A1 - Helm, C.A. A1 - Lindner, A. A1 - Thünemann, Andreas A1 - Menzel, Michael A1 - Higuchi, M. A1 - Kurth, D.G. T1 - The solid-state architecture of a metallosupramolecular polyelectrolyte N2 - Self-assembly of Fe(II) and the ditopic ligand 1,4-bis(2,2':6',2"-terpyridine-4'-yl)benzene results in equilibrium structures in solutions, so-called metallosupramolecular coordination polyelectrolytes (MEPEs). It is exceedingly difficult to characterize such macromolecular assemblies, because of the dynamic nature. Therefore, hardly any structural information is available for this type of material. Here, we show that from dilute solutions, where small aggregates predominate, it is possible to grow nanoscopic crystals at an interface. A near atomic resolution structure of MEPE is obtained by investigating the nanoscopic crystals with electron diffraction in combination with molecular modeling. The analysis reveals a primitive monoclinic unit cell (P21/c space group, a = 10.4 Å, b = 10.7 Å, c = 34.0 Å, α = γ = 90°, β = 95°, ρ = 1.26 g/cm³, and Z = 4). The MEPE forms linear rods, which are organized into sheets. Four sheets intersect the unit cell, while adjacent sheets are rotated by 90° with respect to each other. The pseudooctahedral coordination geometry of the Fe(II) centers is confirmed by Mössbauer spectroscopy. The combination of diffraction and molecular modeling presented here may be of general utility to address problems in structural materials science. KW - Polymer KW - Polyelectrolyte KW - Electron diffraction KW - Mössbauer spectroscopy KW - Molecular modeling KW - Supramolecular chemistry PY - 2006 SN - 0027-8424 SN - 1091-6490 VL - 103 IS - 27 SP - 10202 EP - 10206 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-12495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, M. A1 - Scharf, O. A1 - Novak, S. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Hischenhuber, P. A1 - Buzanich, Günter A1 - Meyer, A. A1 - Lopez, V. A1 - McIntosh, K. A1 - Streli, C. A1 - Havrilla, G. A1 - Fittschen, U. T1 - Shading in TXRF: calculations and experimental validation using a color X-ray camera N2 - Absorption effects in total reflection X-ray fluorescence (TXRF) analysis are important to consider, especially if external calibration is to be applied. With a color X-ray camera (CXC), that enables spatially and energy resolved XRF analysis, the absorption of the primary beam was directly visualized for mL-droplets and an array of pL-droplets printed on a Si-wafer with drop-on-demand technology. As expected, deposits that are hit by the primary beam first shade subsequent droplets, leading to a diminished XRF signal. This shading effect was quantified with enhanced precision making use of sub-pixel analysis that improves the spatial resolution of the camera. The measured absorption was compared to simulated results using three different model calculations. It was found they match very well (average deviation < 10%). Thus errors in quantification due to absorption effects can be accounted for in a more accurate manner. KW - absorption KW - X-ray Fluorescence analysis PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-359000 DO - https://doi.org/10.1039/C5JA00127G IS - 10 SP - 2184 EP - 2193 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-35900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fittschen, U.E.A. A1 - Menzel, M. A1 - Scharf, O. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Buzanich, Günter A1 - Lopez, V.M. A1 - McIntosh, K. A1 - Streli, C. A1 - Havrilla, G.J. T1 - Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera N2 - Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by 'drop on demand' technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. KW - TXRF KW - Full field micro-XRF KW - Color X-ray camera PY - 2014 DO - https://doi.org/10.1016/j.sab.2014.06.025 SN - 0584-8547 SN - 0038-6987 VL - 99 SP - 179 EP - 184 PB - Elsevier CY - Amsterdam AN - OPUS4-31180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -