TY - CONF A1 - Erning, Wilhelm A1 - Dimper, Matthias A1 - Ahrens, A. A1 - Reimann, S. ED - Stojanovic, I. ED - Alar, V. ED - Simunovic, V. T1 - Corrosion behaviour of stainless steel in contact with ECA-generated disinfectant fluids N2 - The generation of active disinfectants by electrochemical processes gains market share due to the lack of need for transportation and storage of dangerous goods as well as the ease of operation. Usually the process involves the use of specific electrodes for electrolysis of water to produce active chlorine species, sometimes supported by addition of chlorides to the process water. The resulting ECA (ElectroChemically Activated) solutions can cause corrosion due to the content of free active chlorine (FAC) or due to the chloride content of the process solution. These fluids are widely used because they show a good chemical and microbiological stability, are well suited for the standard cleaning procedures and allow reducing germ concentrations to meet hygienic standards. The influence of the respective agents to alloy 1.4301 is investigated by storage experiments and by electrochemical investigations. The results show, that the influence of chlorides is higher for short-term experiments. ECA-Fluids with low chloride concentrations are preferable. The goal of the investigations is to creat evaluation guidelines for the application parameters to provide a sufficient cleansing effect without causing corrosion of the surfaces. T2 - 22. Savjetovanje o zaštiti materijala i industrijskom finišu Kormat 2016 CY - Zagreb, Croatia DA - 20.04.2016 KW - Disinfection pitting corrosion stainless steel PY - 2016 SN - 1848-4255 SP - 43 EP - 49 PB - HRVATSKO DRUŠTVO ZA ZAŠTITU MATERIJALA CY - Zagreb, Croatia AN - OPUS4-35807 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kamaraj, Abinaya A1 - Erning, Johann Wilhelm A1 - Reimann, S. A1 - Ahrens, A. T1 - Susceptibility of 304 stainless steel to crevice corrosion in electrochemically active fluids N2 - The susceptibility of AISI 304 stainless steel to crevice corrosion on the effect of contact with electrochemically active fluids was investigated using exposure and stepwise potentiostatic polarisation. Crevice materials made up of 304 SS and Polyether ether ketone (PEEK) forming two kinds of crevices including 304 SS-to-PEEK and 304 SS-to-304 SS were tested. T2 - NACE International Corrosion Conference 2019 CY - Nashville, TN, USA DA - 24.03.2019 KW - Steel KW - Crevice KW - Corrosion KW - ECA KW - Stainless PY - 2019 SP - Paper 12868 PB - NACE International CY - Houston AN - OPUS4-49286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Varadarajan, A. A1 - Allan, R. A1 - Valentin, J. A1 - Castañeda Ocampo, O. A1 - Somerville, V. A1 - Buhmann, M. A1 - West, J. A1 - Skipp, Paul A1 - van der Mei, H. A1 - Ren, Q. A1 - Schreiber, Frank A1 - Webb, J. A1 - Pietsch, Franziska A1 - Ahrens, C. T1 - An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1 N2 - Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential Protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms. KW - Biofilms PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515108 DO - https://doi.org/10.1038/s41522-020-00154-8 VL - 6 IS - 1 SP - Article number: 46 PB - Springer Nature CY - Singapore AN - OPUS4-51510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Clauß, F. A1 - Epple, Niklas A1 - Ahrens, M. A. A1 - Niederleithinger, Ernst A1 - Mark, P. T1 - Correlation of Load-Bearing Behavior of Reinforced Concrete Members and Velocity Changes of Coda Waves N2 - The integral collection of information such as strains, cracks, or temperatures by ultrasound offers the best prerequisites to monitor structures during their lifetime. In this paper, a novel approach is proposed which uses the collected information in the coda of ultrasonic signals to infer the condition of a structure. This approach is derived from component tests on a reinforced concrete beam subjected to four-point bending in the lab at Ruhr University Bochum. In addition to ultrasonic measurements, strain of the reinforcement is measured with fiber optic sensors. Approached by the methods of moment-curvature relations, the steel strains serve as a reference for velocity changes of the coda waves. In particular, a correlation between the relative velocity change and the average steel strain in the reinforcement is derived that covers 90% of the total bearing capacity. The purely empirical model yields a linear function with a high level of accuracy (R 2 =0.99, R2=0.99, RMSE≈90μ RMSE≈90μ strain). KW - Ultrasound KW - Coda Wave Interferometry (CWI) KW - Structural Health Monitoring KW - Reinforced Concrete KW - Embedded Sensors PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542316 DO - https://doi.org/10.3390/ma15030738 VL - 15 IS - 3 SP - 738 PB - MDPI AN - OPUS4-54231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst A1 - Epple, Niklas A1 - Fontoura Barroso, Daniel A1 - Clauß, F. A1 - Ahrens, M. A. A1 - Mark, P. ED - Krieger, J. ED - Isecke, B. T1 - Ultraschallbasierte Überwachung von Stahl- und Spannbeton-konstruktionen – erste Ergebnisse der DFG-Forschungsgruppe 2825 CoDA N2 - Die Überwachung von Bauteilen aus Stahl- oder Spannbeton mit Ultraschall hat in Labor- und Technikumsversuchen schon vielversprechende Ergebnisse gezeigt. Besonders gute Resultate wurden dabei mit eingebetteten Ultraschalltrans-ducern und bei Auswertung der Daten mit der hochsensiblen Codawelleninterferometrie erzielt. Erfasst werden können neben Temperatur- und Feuchteeffekten auch Belastungszustände und jegliche Art von Schädigung, die mit Mikro- oder Makrorissbildung einhergeht. Seit 2019 untersucht die DFG-Forschergruppe 2825 „CoDA“ (Sprecher: Prof. Christoph Gehlen, TU München) ver-schiedenste Aspekte dieser innovativen Technologie mit dem Ziel, Einflussgrößen quantitativ zu erfassen, Umweltein-flüsse zu korrigieren und 3D-Auswerteverfahren zu verbessern. Final soll eine am Bauwerk einsatzfähige Methode ent-stehen, die klassische Monitoringverfahren ergänzt und erweitert sowie Input zu einem Update des statischen Systems liefert. Aufgaben der BAM in der Forschergruppe ist neben Verbesserung und Adaptierung der Messsystem und Sensorik auch Langzeitversuche an einem Großobjekt und Testinstallationen an Realbauwerken. Hierzu liegen erste Ergebnisse vor, die zeigen, dass die Technologie auch außerhalb des Labors einsatzfähig ist. T2 - 4. Brückenkolloquium CY - Online meeting DA - 08.09.2020 KW - Brücke KW - Monitoring KW - Ultraschall KW - Codawelleninterferometrie PY - 2020 SN - 978-3-8169-3518-6 SP - 473 EP - 480 PB - expert CY - Tübingen AN - OPUS4-51205 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Clauß, F. A1 - Epple, Niklas A1 - Ahrens, M. A. A1 - Niederleithinger, Ernst A1 - Mark, P. T1 - Comparison of Experimentally Determined Two-Dimensional Strain Fields and Mapped Ultrasonic Data Processed by Coda Wave Interferometry N2 - Due to the high sensitivity of coda waves to the smallest structural alterations such as strain, humidity or temperature changes, ultrasonic waves are a valid means to examine entire structures employing networks of ultrasonic transducers. In order to substantiate this ex ante assessment, the viability of measuring ultrasonic waves as a valid point of reference and inference for structural changes is to be further scrutinized in this work. In order to investigate the influence of mechanical strain on ultrasonic signals, a four-point bending test was carried out on a reinforced concrete beam at Ruhr University Bochum. Thus, measurements collected from a network of selected transducer pairings arranged across the central, shear-free segment of the test specimen, were correlated to their respective strain fields. Detected ultrasonic signals were evaluated employing Coda Wave Interferometry. Such analysis comprised the initial non-cracked state as well as later stages with incremental crack depth and quantity. It was to ascertain that the test specimen can in fact be qualitatively compartmentalized into areas of compression and tension identified via Relative Velocity Changes presented in Attribute Maps. However, since results did not entail a zero crossing, i.e., neither positive nor negative values were to be calculated, only relative changes in this work displayed staggered over the height of the object under test, are discussed. Under the given methodological premises, additional information is currently required to make quantitative assertions regarding this correlation of ultrasonic and strain results. This holds true for the comparability of the ultrasonic and strain results for both non-cracked and even the cracked state. KW - Digital image correlation KW - Fiber optic sensors KW - Coda Wave Interferometry KW - Ultrasound KW - Concrete PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510501 DO - https://doi.org/10.3390/s20144023 SN - 1424-8220 VL - 20 IS - 14 SP - Paper 4023, 1 PB - MDPI CY - Basel AN - OPUS4-51050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dürig, Wiebke A1 - Lindblad, Sofia A1 - Golovko, Oksana A1 - Gkotsis, Georgios A1 - Aalizadeh, Reza A1 - Nika, Maria-Christina A1 - Thomaidis, Nikolaos A1 - Alygizakis, Nikiforos A. A1 - Plassmann, Merle A1 - Haglund, Peter A1 - Fu, Qiuguo A1 - Hollender, Juliane A1 - Chaker, Jade A1 - David, Arthur A1 - Kunkel, Uwe A1 - Macherius, André A1 - Belova, Lidia A1 - Poma, Giulia A1 - Preud'Homme, Hugues A1 - Munschy, Catherine A1 - Aminot, Yann A1 - Jaeger, Carsten A1 - Lisec, Jan A1 - Hansen, Martin A1 - Vorkamp, Katrin A1 - Zhu, Linyan A1 - Cappelli, Francesca A1 - Roscioli, Claudio A1 - Valsecchi, Sara A1 - Bagnati, Renzo A1 - González, Belén A1 - Prieto, Ailette A1 - Zuloaga, Olatz A1 - Gil-Solsona, Ruben A1 - Gago-Ferrero, Pablo A1 - Rodriguez-Mozaz, Sara A1 - Budzinski, Hélène A1 - Devier, Marie-Helene A1 - Dierkes, Georg A1 - Boulard, Lise A1 - Jacobs, Griet A1 - Voorspoels, Stefan A1 - Rüdel, Heinz A1 - Ahrens, Lutz T1 - What is in the fish? Collaborative trial in suspect and non-target screening of organic micropollutants using LC- and GC-HRMS N2 - A collaborative trial involving 16 participants from nine European countries was conducted within the NORMAN network in efforts to harmonise suspect and non-target screening of environmental contaminants in whole fish samples of bream (Abramis brama). Participants were provided with freeze-dried, homogenised fish samples from a contaminated and a reference site, extracts (spiked and non-spiked) and reference sample preparation protocols for liquid chromatography (LC) and gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS). Participants extracted fish samples using their in-house sample preparation method and/or the protocol provided. Participants correctly identified 9-69% of spiked compounds using LC-HRMS and 20-60% of spiked compounds using GC-HRMS. From the contaminated site, suspect screening with participants’ own suspect lists led to putative identification of on average ~145 and ~20 unique features per participant using LC-HRMS and GC-HRMS, respectively, while non-target screening identified on average ~42 and ~56 unique features per participant using LC-HRMS and GC-HRMS, respectively. Within the same sub-group of sample preparation method, only a few features were identified by at least two participants in suspect screening (16 features using LC-HRMS, 0 features using GC-HRMS) and non-target screening (0 features using LC-HRMS, 2 features using GC-HRMS). The compounds identified had log octanol/water partition coefficient (KOW) values ranging from -9.9 to 16 and mass-to-charge ratio (m/z) of 68 to 761 (LC-HRMS and GC-HRMS). A significant linear trend was found between log KOW and m/z for the GC-HRMS data. Overall, these findings indicate that differences in screening results are mainly due to the data analysis workflows used by different participants. Further work is needed to harmonise the results obtained when applying suspect and non-target screening approaches to environmental biota samples. KW - General Environmental Science KW - Suspect and non-target analysis KW - Biota KW - Expobome KW - Collaborative trial PY - 2023 DO - https://doi.org/10.1016/j.envint.2023.108288 VL - 181 SP - 1 EP - 24 PB - Elsevier B.V. AN - OPUS4-58681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -