TY - CONF
A1 - Maierhofer, Christiane
A1 - Ziegler, Mathias
A1 - Kunert, M.
A1 - Goldammer, M.
T1 - Entwicklung von Referenzprobekörpern für die Standardisierung der Blitzthermografie
N2 - Die aktive Thermografie wird in der Industrie zunehmend in verschiedenen Bereichen zur Qualitätssicherung, Zustandsdiagnose und Zustandsüberwachung eingesetzt. Bestehende Normen zur Thermografie beschreiben die Grundlagen, Geräte und Begriffe. In diesem Beitrag wird über ein Projekt berichtet, dessen Ziel die Erarbeitung einer Prüfnorm zur Blitzthermografie ist. Diese sollte neben der Auswahl geeigneter Gerätekomponenten, der Auswertungsverfahren und der Vorgehensweise bei der Prüfung auch die Beschreibung geeigneter Referenzprobekörper enthalten, die eine Bewertung der Messapparatur und eine Qualitätssicherung der Prüfung ermöglichen.
T2 - Thermographie-Kolloquium 2011
CY - Stuttgart, Germany
DA - 29.09.2011
KW - Aktive Thermografie
KW - Blitzanregung
KW - Prüfnorm
KW - Referenzprobekörper
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246230
SN - 978-3-940283-36-8
VL - 130
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-24623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlichting, Joachim
A1 - Ziegler, Mathias
A1 - Pelkner, Matthias
A1 - Maierhofer, Christiane
A1 - Kreutzbruck, Marc
T1 - Kameragestütztes Flying-Spot-Verfahren zur Risserkennung
N2 - In dieser Arbeit wird ein kameragestütztes Verfahren zur Flying-
Spot-Thermografie vorgestellt. Die Anregung wird über einen Diodenlaser mit einem optischen Scanner realisiert. Bei der Auswertung kommt ein effizienter und robuster Algorithmus zum Einsatz, der direkt auf die mit der Kamera aufgenommene Thermografiesequenz angewendet werden kann, ohne auf eine
Synchronisation zwischen Kamera und Lasersystem angewiesen zu sein. Daher eignet sich diese Herangehensweise besonders zur Nachrüstung bestehender Thermografiesysteme.
Die prinzipielle Eignung dieser Methode wird anhand einer Messung an einem Schienenstück mit Rollkontaktermüdungsrissen gezeigt. Als Referenzverfahren werden die Magnetpulverprüfung und eine auf GMR (Giant Magnetoresistance)- Sensoren basierende Streufeldmessung herangezogen. Mit dem thermografischen Verfahren konnten sämtliche enthaltenen Fehler erkannt werden. Dabei wurden Risse im mm-Abstand getrennt nachgewiesen, was etwa der geometrischen Auflösung der eingesetzten Kamera entspricht.
T2 - Thermographie-Kolloquium 2011
CY - Stuttgart, Germany
DA - 29.09.2011
KW - Flying-Spot Thermografie
KW - Diodenlaser
KW - Rissortung
KW - Magnetpulverprüfung
KW - GMR-Sensoren
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246220
SN - 978-3-940283-36-8
IS - DGZfP-BB 130 (Vortrag 09)
SP - 1
EP - 6
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24622
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thummerer, G.
A1 - Mayr, G.
A1 - Hirsch, Philipp Daniel
A1 - Ziegler, Mathias
A1 - Burgholzer, P.
T1 - Photothermal Image Reconstruction in Opaque Media with Virtual Wave Backpropagation
N2 - Thermographic reconstruction of defects that lie in the bulk of a sample is a difficult task because entropy production during heat diffusion leads to information loss. To reconstruct defects one has to solve an inverse heat conduction problem. The quality of the reconstruction is closely related to the information content of the observed data set that is reflected by the decreasing ability to spatially resolve a defect with growing defect depth. In this work we show a 2D reconstruction of rectangular slots with different width-to-depth ratios in a metallic sample. For this purpose, we apply the virtual wave concept and incorporate positivity and sparsity as prior information to overcome the diffusion-based information loss partially. The reconstruction is based on simulated and experimental pulse thermography data. In the first reconstruction step, we compute a virtual wave field from the surface temperature data. This allows us, in the second step, to use ultrasonic backpropagation methods for image reconstruction.
KW - Virtual wave concept
KW - Thermography
KW - Photothermal Technique
KW - Image reconstruction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506166
DO - https://doi.org/10.1016/j.ndteint.2020.102239
VL - 112
SP - 102239
PB - Elsevier Ltd.
CY - Netherlands
AN - OPUS4-50616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Myrach, Philipp
A1 - Schlichting, Joachim
A1 - Maierhofer, Christiane
A1 - Kreutzbruck, Marc
T1 - Laser-Thermografie für die schnelle Prüfung auf mikroskopische Risse in reflektierenden metallischen Oberflächen
N2 - Thermografische ZfP-Verfahren erlauben die Erkennung einer Vielzahl von Defekten in unterschiedlichsten Werkstoffen. Neue Ansätze unter Verwendung von Lasern ermöglichen darüber hinaus die Prüfung auf Oberflächenrisse. Wir stellen die neuesten Entwicklungen dieser vielversprechenden Technik vor und zeigen warum deren Einsatz potentiell die Standardprüfverfahren Magnetpulver- bzw. Eindringprüfung für eine Reihe von Prüfproblemen beerben könnte. Hierzu stellen wir die Prüfergebnisse zu unterschiedlichen metallischen Werkstoffen, Rissgrößen und -typen in Abhängigkeit der Prüfparameter vor. Die aktuelle Grenze der Nachweisempfindlichkeit für die mittels klassischer Thermografie schwer prüfbaren hochreflektierenden Metalloberflächen liegt mit Rissbreiten und -tiefen von weni-gen Mikrometern im Bereich der fluoreszierenden Magnetpulver- und Eindringprüfung. Dabei sind weder Verbrauchsmittel noch eine Oberflächenpräparation notwendig und eine Prüfung kann berührungslos und automatisiert über Entfernungen im Meter-Bereich erfolgen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Thermografie
KW - Laser
KW - Risse
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-288706
SN - 978-3-940283-49-8
IS - DGZfP-BB 141 (Di.2.A.4)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28870
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Röllig, Mathias
A1 - Steinfurth, Henrik
A1 - Ziegler, Mathias
T1 - Untersuchung von Hochleistungs-LEDs für den Einsatz in der zerstörungsfreien Prüfung mittels Thermografie
N2 - Für die optische Erwärmung von Prüfteiloberflächen sind Blitz- und Halogenlampen Stand der Technik. Der Vorteil dieser Wärmequellen liegt in ihren relativ geringen Anschaffungskosten bei gleichzeitig hohen Leistungsdichten am Prüfobjekt. Nachteilig ist bei den Halogenlampen die Limitierung der möglichen Modulationsffequenz auf ca. 1 Hz für die Anwendung dieser Quelle in der Lockin-Thermografie. Blitzlampen bieten für gewöhnlich nur eine feste Blitzdauer bei einer geringen Taktrate. Beide Anregungsquellen müssen in Reflexionsanordnung mit Filtern betrieben werden um die entstehende thermische Eigenstrahlung als Störquelle zu eliminieren. Wir stellen Untersuchungen an Hochleistungs-LEDs für den Einsatz in der aktiven Thermografie vor. Diese Lichtquellen werden durch die rasante Entwicklung der möglichen Leistungsdichten nun auch für die thermografische ZfP interessant. Sie zeigen ähnlich dem Laser eine schmale und auf den Werkstoff abstimmbare spektrale Verteilung der Strahlungsleistung bei moderaten Kosten. Die zugrunde liegende Elektrolumineszenz generiert kaum Wärmestrahlung und ermöglicht dadurch die Prüfung während des Erwärmungsvorganges ohne größeren Aufwand. Modulationsfrequenzen über 100 Hz mit thermischen Eindringtiefen < 1 mm sind möglich. Dadurch qualifizieren sich die LEDs zur Anwendung in der Lockin-Thermografie von Metallen und zur oberflächennahen Prüfung von Schichtsystemen. Durch die fast verzögerungsffeie Reaktion der LED auf das steuernde Signal sind nahezu beliebige zeitliche Anregungsformen möglich. Mit solch flexiblen Anregungsformen ließen sich bereits bei den photothermischen Verfahren erfolgreich höhere Tiefenreichweiten und -auflösungen gegenüber den klassischen Methoden der monofrequenten Lockin - und energiereichen Kurzimpuls-Anregung erzielen. Untersuchungen dieser Möglichkeiten im praktischen Einsatz der HochleistungsLEDs werden vorgestellt und mit herkömmlichen Lichtquellen verglichen.
T2 - Thermographie-Kolloquium 2013
CY - Leinfelden-Echterdingen, Germany
DA - 2013-09-26
KW - Thermografie
KW - Hochleistungsleuchtdioden
KW - Hohe Prüfraten
KW - Schnelle Modulationsfrequenzen
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293975
SN - 978-3-940283-52-8
VL - DGZfP-BB 143
SP - Vortrag 3, 1
EP - 8
AN - OPUS4-29397
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Heideklang, René
A1 - Myrach, Philipp
A1 - Onel, Yener
A1 - Pelkner, Matthias
A1 - Pohl, Rainer
A1 - Stegemann, Robert
A1 - Ziegler, Mathias
A1 - Kreutzbruck, Marc
T1 - Vergleich konventioneller und neuer Oberflächenprüfverfahren für ferromagnetische Werkstoffe
N2 - Sicherheitsrelevante und zyklisch hoch belastete Bauteile erfordern zur Vermeidung von kostenintensiven Ausfällen besonders stabile Prozessparameter. Bereits sehr kleine Randzonenfehler können unter zyklischer Bauteilbelastung zu Risswachstum und letztendlich zum Bauteilversagen führen. Die frühzeitige Erkennung von Randzonenfehler in Hochleistungsbauteilen wie z.B. Zahnräder, Ritzelwellen und Kurbelwellen erfordert daher eine leistungsfähige zerstörungsfreie Oberflächenrissprüfung, die es ermöglicht in den hochbeanspruchten Funktionsflächen auch Härterisse, Schleifrisse oder Zundereinschlüsse zu detektieren.
Hierzu sind in den letzten Jahren einige neue, innovative Oberflächenprüfverfahren wie die laserangeregte Thermografie und die Streuflussprüfung mit hochauflösenden GMR-Sensoren oder magnetooptischen Verfahren entwickelt worden. Zusätzlich zur hohen Empfindlichkeit zeichnen sich diese innovativen Verfahren durch einen schnellen und teils auch berührungslosen Einsatz aus. Da die noch relativ neu-en Verfahren naturgemäß noch nicht normativ verankert sind, wurden auch bereits erste Validierungen durchgeführt. Um die Leistungsfähigkeit der Verfahren eingehend zu untersuchen, erfolgten Testreihen an verschiedenen Testkörpern in Bezug auf Ortsauflösung, Empfindlichkeit, Automatisierung und Bewertung der Messsig-nale.
Neben den neuen Verfahren und ihren ersten Schritten hin zur Validierung kamen als Referenz auch die „klassischen“ Verfahren der Magnetpulver- und Wirbelstromprüfung zum Einsatz, deren Leistungsfähigkeit durch angepasste Sondenentwicklung auch für sehr kleine Oberflächendefekte nochmals unter Beweis gestellt wurde. Zusätzlich wurde an einigen Testkörpern eine hochauflösende CT durchgeführt. Die Ergebnisse dieses Vergleiches werden vorgestellt und Möglichkeiten sowie Grenzen der einzelnen Verfahren herausgearbeitet.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Zerstörungsfreie Prüfung
KW - Oberflächenprüfung
KW - Vergleichskörper 1
KW - Sichtprüfung
KW - Magnetpulverprüfung
KW - Streuflussprüfung
KW - Farbeindringprüfung
KW - Wirbelstromprüfung
KW - Thermografie
KW - Radiografie
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344262
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Mi.2.B.4, 1
EP - 11
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-34426
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Bogoclu, Can
A1 - Emmerling, Franziska
A1 - Streli, Christina
A1 - Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach
N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications.
KW - Machine Learning
KW - GE-XANES
KW - Bayesian Optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955
DO - https://doi.org/10.1088/2632-2153/ad4253
VL - 5
IS - 2
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-60395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, R.
A1 - Seifert, M.
A1 - George, Janine
A1 - Blaurock, S.
A1 - Botti, S.
A1 - Krautscheid, H.
A1 - Grundmann, M.
A1 - Sturm, C.
T1 - Determination of acoustic phonon anharmonicities via second-order Raman scattering in CuI
N2 - We demonstrate the determination of anharmonic acoustic phonon properties via second-order Raman scattering exemplarily on copper iodide single crystals. The origin of multi-phonon features from the second-order Raman spectra was assigned by the support of the calculated 2-phonon density of states. In this way, the temperature dependence of acoustic phonons was determined down to 10 K. To determine independently the harmonic contributions of respective acoustic phonons, density functional theory in quasi-harmonic approximation was used. Finally, the anharmonic contributions were determined. The results are in agreement with earlier publications and extend CuI’s determined acoustic phonon properties to lower temperatures with higher accuracy. This approach demonstrates that it is possible to characterize the acoustic anharmonicities via Raman scattering down to zero-temperature renormalization constants of at least 0.1 cm⁻¹.
KW - Thermoelectrics
KW - Thermal transport
KW - Phonon interactions
KW - Density functional theory
KW - Phonons
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593164
DO - https://doi.org/10.1088/1367-2630/ad1141
SN - 1367-2630
VL - 25
IS - 12
SP - 1
EP - 12
PB - IOP Publishing
CY - London
AN - OPUS4-59316
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 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Joester, Maike
A1 - Reinholz, Uwe
A1 - Radtke, Martin
A1 - Bienert, Ralf
A1 - Schulz, K.
A1 - Schmack, R.
A1 - Kraehnert, R.
A1 - Emmerling, Franziska
T1 - Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS
N2 - The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles. We studied the particle formation mechanism using triethanolamine as reactant and stabilizing agent. In situ fast-X-ray absorption near edge spectroscopy and small-angle X-ray scattering provide information on the oxidation state and the structural information at the same time. In situ data were complemented by ex situ transmission electron microscopy, wide-angle X-ray scattering and Raman analysis of the formed nanoparticles. The formation of maghemite nanoparticles (γ-Fe2O3) from ferric and ferrous chloride was investigated. Prior to the formation of these nanoparticles, the formation and conversion of intermediate phases (akaganeite, iron(II, III) hydroxides) was observed which undergoes a morphological and structural collapse. The thus formed small magnetite nanoparticles (Fe3O4) grow further and convert to maghemite with increasing reaction time.
KW - oxidation state
KW - structural information
KW - maghemite
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351376
DO - https://doi.org/10.1039/C5CE01585E
SN - 1466-8033
VL - 17
IS - 44
SP - 8463
EP - 8470
CY - London, UK
AN - OPUS4-35137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Riesemeier, Heinrich
A1 - Emmerling, Franziska
T1 - Time- & spatial-resolved X-ray absorption fine structure (XAFS) spectroscopy in a single-shot – new analytical possibilities for in situ material characterization
N2 - A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved.
KW - Time resolution
KW - Single-shot XAFS
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370892
DO - https://doi.org/10.1107/S1600577516003969
SN - 1600-5775
IS - 23
SP - 769
EP - 776
PB - International Union of Crystallography
CY - Chester, UK
AN - OPUS4-37089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Buzanich, Günter
A1 - Curado, Jessica
A1 - Reinholz, Uwe
A1 - Riesemeier, Heinrich
A1 - Scharf, O.
T1 - Slicing - a new method for non destructive 3D elemental sensitive characterization of materials
N2 - Recent advances in synchrotron sources and detector technology have led to substantial improvements in spatial resolution and detection limits for X-ray fluorescence analysis (XRF). However, the non-destructive three-dimensional elemental sensitive characterization of samples remains a challenge. We demonstrate the use of the so-called 'Color X-ray Camera' (CXC) for 3D measurements for the first time. The excitation of the sample is realized with a thin sheet-beam. The stepwise movement of the sample allows getting the elemental distribution for each layer with one measurement. These layers can be combined to a full 3D dataset for each element afterwards. Since the information is collected layer by layer, there is no need to apply reconstruction techniques, which quite often are the reason for artifacts in the results achieved by computed tomography (CT). The field of applications is wide, as the 3D elemental distribution of a material contains clues to processes inside the samples from a variety of origins. The technique is of special interest and well suited for biological specimens, because their light matrix minimizes restricting absorption effects. Measurement examples of a hornet and the teeth of a Sorex araneus are shown.
KW - SR-microXRF
KW - 3D
KW - CXC
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324330
DO - https://doi.org/10.1039/c4ja00085d
SN - 0267-9477
SN - 1364-5544
VL - 29
IS - 8
SP - 1339
EP - 1344
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-32433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachmöller, O.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Aichler, M.
A1 - Radtke, Martin
A1 - Dietrich, D.
A1 - Schwamborn, K.
A1 - Lutz, L.
A1 - Werner, M.
A1 - Sperling, M.
A1 - Walch, A.
A1 - Karst, U.
T1 - Elemental bioimaging and speciation analysis for the investigation of Wilsons disease using μXRF and XANES
N2 - A liver biopsy specimen from a Wilson’s disease (WD) patient was analyzed by means of micro-X-ray fluorescence (mXRF) spectroscopy to determine the elemental distribution. First, bench-top mXRF was utilized for a coarse scan of the sample under laboratory conditions. The resulting distribution maps of copper and iron enabled the determination of a region of interest (ROI) for further analysis. In order to obtain more detailed elemental information, this ROI was analyzed by synchrotron radiation (SR)-based mXRF with a beam size of 4 mm offering a resolution at the cellular level. Distribution maps of additional elements to copper and iron like zinc and manganese were obtained due to a higher sensitivity of SR-mXRF. In addition to this, X-ray absorption near edge structure spectroscopy (XANES) was performed to identify the oxidation states of copper in WD. This speciation analysis indicated a mixture of copper(I) and copper(II) within the WD liver tissue.
KW - progressive hepatolenticular degeneration
KW - mXRF Micro-X-ray fluorescence spectroscopy
KW - XANES X-ray absorption near edge structure spectroscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-360811
DO - https://doi.org/10.1039/C6MT00001K
SN - 1756-5901
SN - 1756-591X
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-36081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de O. Primo, J.
A1 - Horsth, D.F.
A1 - de S. Correa, J.
A1 - Das, A.
A1 - Bittencourt, C.
A1 - Umek, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Zanetta, C.
A1 - Anaissi, F.J.
T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water
N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis-
infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake
water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency.
KW - Synchrotron
KW - BAMline
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440
DO - https://doi.org/10.3390/nano12101764
SN - 2079-4991
VL - 12
IS - 10
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-56244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernges, T.
A1 - Hanus, R.
A1 - Wankmiller, B.
A1 - Imasato, K.
A1 - Lin, S.
A1 - Ghidiu, M.
A1 - Gerlitz, M.
A1 - Peterlechner, M.
A1 - Graham, S.
A1 - Hautier, G.
A1 - Pei, Y.
A1 - Hansen, M. R.
A1 - Wilde, G.
A1 - Snyder, G. J.
A1 - George, Janine
A1 - Agne, M T.
A1 - Zeier, W. G.
T1 - Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity
N2 - Next-generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two-channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non-propagating diffuson-like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson-mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson-mediated transport. Bridging the fields of solid-state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so-called Meyer-Neldel behavior in ionic conductors to phonon occupations.
KW - Diffusons
KW - DFT
KW - Phonons
KW - Thermoelectrics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547140
DO - https://doi.org/10.1002/aenm.202200717
SN - 1614-6832
VL - 12
IS - 22
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-54714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Margreiter, R.
A1 - Baumann, J.
A1 - Mantouvalou, I.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Strub, E.
T1 - Investigations on fire-gilding
N2 - Fire-gilding is a historic technique for the application of golden layers on a number of different base materials utilizing a gold amalgam. This technique leaves a significant amount of Hg in the golden layer, giving archeometrists a reliable indicator to identify firegildings.
Recent findings on presumably fire-gilded objects have shown in several cases significantly lower Hg content than previously studied objects. This prompted a synchrotron-based X-ray fluorescence investigation into the Hg distribution along the material–gilding interface, as well as a series of measurements regarding the Hg content development in fire-gilded samples during artificial aging. This work presents findings on laboratory-prepared fire-gildings, indicating an Hg enrichment at the interface of firegilded silver samples. Notably, such an enrichment is missing in fire-gilded copper samples. Further, it is confirmed that fire-gilded layers typically do not undercut an Hg bulk content of 5%. In this light, it seems improbable that ancient samples that contain <5% Hg are fire-gilded. The results presented in this study might lead to a non-destructive method to identify the Hg enrichment at the interface. This might be obtained by a combination of different non-destructive measurements and might also work unambiguously in samples in which the gold top layer is altered.
KW - BAMline
KW - X-Ray Fluorescence
KW - Gilding
KW - Depth profile
KW - Archaeometry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552885
DO - https://doi.org/10.1111/arcm.12797
SN - 0003-813X
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-55288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Haider, M. Bilal
A1 - Emmerling, Franziska
A1 - F. M. Oliveira, P.
A1 - Michalchuk, Adam A. L.
T1 - Dispersive x-ray absorption spectroscopy for time-resolved in situ monitoring of mechanochemical reactions
N2 - X-ray absorption spectroscopy (XAS) provides a unique, atom-specific tool to probe the electronic structure of solids. By surmounting long-held limitations of powder-based XAS using a dynamically averaged powder in a Resonant Acoustic Mixer (RAM), we demonstrate how time-resolved in situ (TRIS) XAS provides unprecedented detail of mechanochemical synthesis. The use of a custom-designed dispersive XAS (DXAS) setup allows us to increase the time resolution over existing fluorescence measurements from ∼15 min to 2 s for a complete absorption spectrum. Hence, we here establish TRIS-XAS as a viable method for studying mechanochemical reactions and sampling reaction kinetics. The generality of our approach is demonstrated through RAM-induced (i) bottom-up Au nanoparticle mechanosynthesis and (ii) the synthesis of a prototypical metal organic framework, ZIF-8. Moreover, we demonstrate that our approach also works with the addition of a stainless steel milling ball, opening the door to using TRIS-DXAS for following conventional ball milling reactions. We expect that our TRIS-DXAS approach will become an essential part of the mechanochemical tool box.
KW - In situ studies
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567659
DO - https://doi.org/10.1063/5.0130673
SN - 1089-7690
VL - 157
IS - 21
SP - 1
EP - 12
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-56765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lecompagnon, Julien
A1 - Ahmadi, Samim
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Thermographic detection of internal defects using 2D photothermal super resolution reconstruction with sequential laser heating
N2 - Thermographic photothermal super resolution reconstruction enables the resolution of internal defects/inhomogeneities below the classical limit, which is governed by the diffusion properties of thermal wave propagation. Based on a combination of the application of special sampling strategies and a subsequent numerical optimization step in post-processing, thermographic super resolution has already proven to be superior to standard thermographic methods in the detection of one-dimensional defect/inhomogeneity structures. In our work, we report an extension of the capabilities of the method for efficient detection and resolution of defect cross sections with fully two-dimensional structured laser-based heating. The reconstruction is carried out using one of two different algorithms that are proposed within this work. Both algorithms utilize the combination of several coherent measurements using convex optimization and exploit the sparse nature of defects/inhomogeneities as is typical for most nondestructive testing scenarios. Finally, the performance of each algorithm is rated on reconstruction quality and algorithmic complexity. The presented experimental approach is based on repeated spatially structured heating by a high power laser. As a result, a two-dimensional sparse defect/inhomogeneity map can be obtained. In addition, the obtained results are compared with those of conventional thermographic inspection methods that make use of homogeneous illumination. Due to the sparse nature of the reconstructed defect/inhomogeneity map, this comparison is performed qualitatively.
KW - Thermography
KW - Super resolution
KW - NDT
KW - Inspection
KW - Internal defects
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548351
DO - https://doi.org/10.1063/5.0088102
SN - 1089-7550
VL - 131
IS - 18
SP - 1
EP - 12
PB - AIP Publishing
AN - OPUS4-54835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iro, M.
A1 - Ingerle, D.
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kregsamer, P.
A1 - Streli, C.
T1 - Investigation of polycapillary half lenses for quantitative confocal micro-X-ray fluorescence analysis
N2 - The use of polycapillary optics in confocal micro-X-ray fluorescence analysis (CMXRF) enables the destruction-free 3D investigation of the elemental composition of samples. The energy-dependent transmission properties, concerning intensity and spatial beam propagation of three polycapillary half lenses, which are vital for the quantitative interpretation of such CMXRF measurements, are investigated in a monochromatic confocal laboratory setup at the Atominstitut of TU Wien, and a synchrotron setup on the BAMline beamline at the BESSY II Synchrotron, Helmholtz-Zentrum-Berlin. The empirically established results, concerning the intensity of the transmitted beam, are compared with theoretical values calculated with the polycap software package and a newly presented analytical model for the transmission function.
The resulting form of the newly modelled energy-dependent transmission function is shown to be in good agreement with Monte Carlo simulated results for the complete energy regime, as well as the empirically established results for the energy regime between 6 keV and 20 keV. An analysis of possible fabrication errors was conducted via pinhole scans showing only minor fabrication errors in two of the investigated polycapillary optics. The energy-dependent focal spot size of the primary polycapillary was investigated in the laboratory via the channel-wise evaluation of knife-edge scans. Experimental results are compared with data given by the manufacturer as well as geometric estimations for the minimal focal spot size. Again, the resulting measurement points show a trend in agreement with geometrically estimated results and manufacturer data.
KW - BAMline
KW - Synchrotron
KW - Capillary
KW - confocal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562430
DO - https://doi.org/10.1107/S1600577522009699
SN - 1600-5775
VL - 29
SP - 1376
EP - 1384
PB - International Union of Crystallography
CY - Chester
AN - OPUS4-56243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Hochaufgelöste thermografische Detektion eingeschlossener Defekte mit Hilfe von 2Dstrukturierten Beleuchtungsmustern
N2 - Für die aktive Thermografie als zerstörungsfreie Prüfmethode galt lange Zeit die Faustformel, dass die Auflösung interner Defekte/Inhomogenitäten auf ein Verhältnis von Defekttiefe/Defektgröße ≤ 1 beschränkt ist. Die Ursache hierfür liegt in der diffusiven Natur der Wärmeleitung in Festkörpern. Sogenannte Super-Resolution-Ansätze erlauben seit Kurzem die Überwindung dieser physikalischen Grenze um ein Vielfaches. Damit ergibt sich die attraktive Möglichkeit die Thermografie von einem rein oberflächensensitiven Prüfverfahren hin zu einem Verfahren mit verbesserter Tiefenreichweite zu entwickeln. Wie weit diese Entwicklung getrieben werden kann, ist Gegenstand aktueller Forschung.
Wir konnten bereits zeigen, dass diese klassische Grenze für 1D- und 2D Defektgeometrien mit Hilfe des Abscannens des Prüfkörpers mittels einzelner Laserspots und der anschließenden Anwendung von photothermischer Super-Resolution-Rekonstruktion überwunden werden kann. Bei dieser Methode wird eine Kombination aus sequenzieller räumlich strukturierter Beleuchtung und numerischen Optimierungsmethoden eingesetzt. Dies geschieht allerdings auf Kosten der experimentellen Komplexität, die zu einer langen Messdauer, großen Datensätzen und langwieriger numerischer Auswertung führt.
In dieser Arbeit berichten wir über einen neuen experimentellen Ansatz, bei dem räumlich strukturierte 2D-Beleuchtungsmuster in Verbindung mit Compressed-Sensing und Computational-Imaging-Methoden verwendet werden, um die experimentelle Komplexität deutlich zu verringern und die Methode für die Untersuchung größerer Prüfflächen nutzbar zu machen.
Der experimentelle Ansatz basiert dabei auf der wiederholten (blinden) photothermischen Anregung mit räumlich strukturierten 2D-Mustern unter Verwendung moderner Projektortechnik und eines Hochleistungslasers. In der anschließenden numerischen Rekonstruktion werden mehrere Messungen unter Ausnutzung der Joint-Sparsity der Defekte innerhalb des Prüfkörpers mittels nichtlinearer konvexer Optimierungsmethoden kombiniert. Als Ergebnis kann eine 2D-sparse Defekt-/Inhomogenitätskarte erstellt werden.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Thermografie
KW - Super resolution
KW - NDT
KW - ZfP
KW - Eingeschlossene Defekte
KW - Projektor
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548945
SN - 978-3-947971-25-1
VL - 177
SP - 1
EP - 16
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung
AN - OPUS4-54894
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandow, Nicole
A1 - Simon, Franz-Georg
T1 - Significance of cadmium from artists' paints to agricultural soils and the food chain
N2 - Background: An Annex XV restriction dossier for cadmium in artists’ paints was submitted by an EU member state to the European Chemicals Agency ECHA. By cleaning used brushes under the tap cadmium can enter the food chain via waste water treatment and subsequent agricultural application of the sewage sludge. It was estimated that 110 kg Cd per year is spread on agricultural land via this exposure route. Other sources of Cd amount to almost 120 tons per year.
Results: The mobility of Cd from pigments was studied in a field-like scenario by leaching experiments using soil samples amended with sewage sludge and spiked with Cd pigments in percolation columns. The redox conditions were confirmed to be the decisive factor for the release of Cd. The release of Cd from artists’ paints was in most cases 1% or lower in the experiments performed.
Conclusions: Application of sewage sludge containing Cd from artist paints does not increase the amount of Cd leached from this soils. Furthermore the quantity of Cd from artists’ paints calculated in the restriction dossier is negligible compared to other sources of Cd to agricultural soil. Therefore ECHA did not consider the proposed restriction to be the most appropriate EU wide measure to address the negligible level of risk.
KW - REACH regulation
KW - Sewage sludge
KW - Fertilizer
KW - Leaching test
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358261
DO - https://doi.org/10.1186/s12302-016-0077-6
SN - 2190-4715
VL - 28
IS - 12
SP - 1
EP - 10
AN - OPUS4-35826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlichting, S.
A1 - Hönig, Gerald
A1 - Müßener, J.
A1 - Hille, P.
A1 - Grieb, T.
A1 - Westerkamp, S.
A1 - Teubert, J.
A1 - Schörmann, J.
A1 - Wagner, M.R.
A1 - Rosenauer, A.
A1 - Eickhoff, M.
A1 - Hoffmann, A.
A1 - Callsen, G.
T1 - Suppression of the quantum-confined Stark effect in polar nitride heterostructures
N2 - Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.
KW - Nanophotonics
KW - Photonic devices
KW - Single photon and quantum effects
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457884
DO - https://doi.org/10.1038/s42005-018-0044-1
SN - 2399-3650
VL - 1
SP - 1
EP - 8
PB - Springer Nature
CY - London
AN - OPUS4-45788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Kunkel, Benny
A1 - Cakir, Cafer Tufan
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Bernstein, Thomas
A1 - Bartling, Stephan
A1 - Radtke, Martin
A1 - Emmerling, Franziska
A1 - Abdel-Mageed, Ali Mohamed
A1 - Wohlrab, Sebastian
A1 - Guilherme Buzanich, Ana
T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy
N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated.
KW - Dispersive XAS
KW - Catalysis
KW - In situ
KW - Structure analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924
DO - https://doi.org/10.1039/d3cc03277a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Petretto, G.
A1 - Naik, Aakash Ashok
A1 - Esters, M.
A1 - Jackson, A. J.
A1 - Nelson, R.
A1 - Dronskowski, R.
A1 - Rignanese, G.-M.
A1 - Hautier, G.
T1 - Automated bonding analysis with crystal orbital Hamilton populuations
N2 - Automated bonding analysis software has been developed based on Crystal Orbital Hamilton Populations to facilitate high-throughput bonding analysis and machine-learning of bonding features. This work presents the software and discusses its applications to simple and complex materials such as GaN, NaCl, the oxynitrides XTaO2N (X=Ca, Ba, Sr) and Yb14Mn1Sb11.
KW - Chemical bonds
KW - Automation
KW - High-throughput
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551641
DO - https://doi.org/10.1002/cplu.202200123
SN - 2192-6506
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Steinfurth, Henrik
A1 - Ziegler, Mathias
A1 - Heck, S.J.
A1 - Scheuerlein, C.
T1 - Aktive Thermografie zur zerstörungsfreien Prüfung von Lötverbindungen
N2 - In diesem Beitrag werden die Möglichkeiten der Ortung von Fehlstellen in Cu Lötverbindungen unterhalb verschiedener Cu Blechdicken mit aktiver Thermografie demonstriert. Dabei wurden die Anregung mit Blitzlicht und die periodische Anregung mit der Lock-In Technik miteinander verglichen. Die Vor- und Nachteile der Anwendung unterschiedlicher IR-Kamerasysteme, einer gekühlten InSb-Quantendetektor IR-Kamera und einer Mikrobolometer IR-Kamera, werden dargestellt. Als objektives Kriterium wurde das SNR für unterschiedliche Fehlstellengrößen herangezogen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Aktive Thermografie
KW - Blitzlichtanregung
KW - Lock-In Anregung
KW - Lötverbindung
KW - Kupfer
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-249935
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.1.C.1)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24993
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Thiel, Erik
A1 - Studemund, Taarna
T1 - Laser-Thermografie – Von der flächigen zur strukturierten Anregung
N2 - Im Bereich der optisch angeregten Thermografie haben sich Blitzlampen (impulsförmig-flächige Erwärmung) und Halogenlampen (moduliert-flächige Erwärmung) für die spezifischen Regime Impuls- und Lockin-Thermografie etabliert.
Mittels eines rasternden fokussierten Lasers wird die Flying-spot Laserthermografie z.B. zur Risserkennung (Dauerstrichbetrieb) und die photothermische Materialcharakterisierung (hochfrequent moduliert)implementiert. Durch die Verfügbarkeit neuer Technologien (schnelle und hochauflösende IR-Kameras, brillante innovativer Lichtquellen und performante Datenakquisitions- und Verarbeitungstechnik) wird ein Paradigmenwechsel von den getrennt voneinander stehenden photothermischen und
thermografischen Techniken hin zu einer einheitlichen quantitativen Mess-und Prüftechnik ermöglicht, die schneller und präziser ist. Ähnlich wie ein LED-Array, jedoch mit einer um zwei Größenordnungen höheren Bestrahlungsstärke, steht jetzt eine neuartige brillante Laserquelle, das VCSEL-Array (vertical-cavity surface-emitting laser) zur Verfügung, welches die starke Beschränkung der zeitlichen Dynamik der etablierten Lichtquellen aufhebt und gleichzeitig spektral sauber von der Detektionswellenlänge getrennt ist. Es vereint somit das schnelle zeitliche Verhalten eines Diodenlasers mit der hohen optischen Bestrahlungsstärke und dem großen Beleuchtungsbereich von Blitzlampen. Darüber hinaus kann die Erwärmung auch strukturiert vorgenommen werden, da einzelne Bereiche des VCSEL-Arrays unabhängig voneinander angesteuert werden können. Dieser neue Freiheitsgrad ermöglicht die Entwicklung ganz neuer thermografischer ZfP-Verfahren.
T2 - Thermographie-Kolloquium 2017
CY - Berlin, Germany
DA - 28.09.2017
KW - Thermografie
KW - Laser
KW - Zerstörungsfreie Prüfung
KW - Lock-in
KW - VCSEL
KW - Photothermisch
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-431170
UR - https://www.dgzfp.de/Portals/thermo2017/BB/6.pdf
SN - 978-3-940283-88-7
VL - 163
SP - 1
EP - 15
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-43117
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Puthiyaveettil, N.
A1 - Kidangan, R.
A1 - Unnikrishnakurup, Sreedhar
A1 - Krishnamurthy, C. V.
A1 - Ziegler, Mathias
A1 - Myrach, Philipp
A1 - Balasubramaniam, K.
T1 - Numerical study of laser line thermography for crack detection at high temperature
N2 - The detection of cracks before the failure is highly significant when it comes to safety-relevant structures. Crack detection in metallic samples at high surface temperature is one of the challenging situation in manufacturing industries.
Laser thermography has already proved its detection capability of surface cracks in metallic samples at room temperature. In this work a continuous wave (CW) laser use to generate a laser, which is using to scan the metal surface with notch.
The corresponding heat distribution on the surface monitored using infrared thermal (IR) camera. A simplified 3D model for laser thermography is developed and validated with experimental results. A dedicated image processing algorithm developed to improve the detectability of the cracks. To understand the dependency of surface temperature, laser power, laser scanning speed etc. in defect detection, we carried out parametric studies with our validated model. Here we Report the capability of laser thermography in crack detection at elevated temperature.
T2 - 14th Quantitative InfraRed Thermography Conference
CY - Berlin, Germany
DA - 25.06.2018
KW - Thermal contrast
KW - Laser Thermography
KW - FEM
KW - Surface cracks
KW - NDT
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499113
DO - https://doi.org/10.21611/qirt.2018.076
SN - 2371-4085
VL - 2018
SP - 685
EP - 686
AN - OPUS4-49911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, Michela
A1 - Tsamos, Athanasios
A1 - Faglioni, Francesco
A1 - Fioresi, Rita
A1 - Zanchetta, Ferdinando
A1 - Bruno, Giovanni
T1 - Geometric deep learning for enhanced quantitative analysis of microstructures in X-ray computed tomography data
N2 - Quantitative microstructural analysis of XCT 3D images is key for quality assurance of materials and components. In this paper we implement a Graph Convolutional Neural Network (GCNN) architecture to segment a complex Al-Si Metal Matrix composite XCT volume (3D image). We train the model on a synthetic dataset and we assess its performance on both synthetic and experimental, manually-labeled, datasets. Our simple GCNN shows a comparable performance, measured via the Dice score, to more standard machine learning methods, but uses a greatly reduced number of parameters (less than 1/10 of parameters), features low training time, and needs little hardware resources. Our GCNN thus achieves a cost-effective reliable segmentation.
KW - Geometric deep learning
KW - Segmentation
KW - Microstructure
KW - X-ray computed tomography
KW - Al–Si metal matrix composites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602517
DO - https://doi.org/10.1007/s42452-024-05985-0
SN - 3004-9261
VL - 6
IS - 6
SP - 1
EP - 9
AN - OPUS4-60251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Pittner, Andreas
A1 - Fabry, Çağtay
T1 - Abschlussbericht IGF 17.923 N: "Sensorgestütztes MSG-Engspaltschweißen von Feinkornstählen mit modifizierter Prozessführung im Dickblechbereich"
N2 - Die im Forschungsvorhaben erzielten Ergebnisse zeigen konkrete technische Lösungen für die automatisierte Anwendung des MSG Engspaltschweißen, sowohl mittels optischer als auch prozessorientierter Sensorik, und sprechen damit ein breites Spektrum möglicher Anwender, insbesondere KMU, an.
Die Seitenführung des Brenners auf Basis der optischen Messgrößen stellt eine robuste und einfach zu implementierende Möglichkeit zur Nahtverfolgung dar. Für die Höhenführung über der Schweißnaht wurde neben der Lösung mittels optischer Messverfahren zusätzlich eine direkt darauf aufbauende Möglichkeit zur Implementierung eines Lichtbogensensors abgeleitet. Das Vorgehen konnte sowohl für Sprühlichtbogenprozesse als auch bei Verwendung von Impulslichtbogenprozessen erfolgreich angewendet werden.
Die zur Sicherstellung eines gleichmäßigen Flankeneinbrandes entwickelte Pendelregelung ist ebenfalls für unterschiedliche Lichtbogenarten einsetzbar und muss vom Anwender auch beim Einsatz einer großen Bandbreite unterschiedlicher Prozessparameter nahezu nicht konfiguriert werden. Neben der im Rahmen der Verfahrensprüfung untersuchten Pendelraupentechnik konnte die Übertragbarkeit des Vorgehens auch auf die Strichraupentechnik anhand von gezielten Schweißversuchen aufgezeigt werden.
Die zunächst auf Basis der optischen Messwerte ausgelegte Füllgradregelung konnte die vorgesehenen Spaltvariationen von 18 bis 24 mm im Rahmen der durchgeführten Verfahrensprüfung ausgleichen. Die Ableitung eines äquivalenten Lichtbogensensors durch Kopplung beider Messprinzipien wurde am Laufzeitende des Vorhabens aufgezeigt, konnte jedoch durch zeitliche Beschränkung nicht für die Verfahrensprüfung berücksichtigt werden.
In Absprache mit dem projektbegleitenden Ausschuss wurde die Entwicklung der Prozessregelung für das Vorhaben auf Schweißungen in Wannenlage und Grundwerkstoffe der Güte S355J2 beschränkt.
Die Qualifizierung des Verfahrens unter Einsatz der beschriebenen Regelalgorithmen nach DIN EN ISO 15614-1 konnte für alle betrachteten Spaltbreiten zwischen 18 und 24 mm anhand einer 50 mm dicken Demonstratorprobe nachgewiesen werden.
KW - Schutzgasschweißen
KW - MSG-Engspaltschweißen
KW - Prozesssteuerung
KW - Lichtbogensensorik
KW - Prozessregelung
KW - GMAW
KW - Narrow gap GMAW
KW - GMAW control
KW - Arc-sensing
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390934
SP - 1
EP - 38
AN - OPUS4-39093
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Hirthammer, Volker
A1 - Rethmeier, Michael
T1 - Recommendations for an Open Science approach to welding process research data
N2 - The increasing adoption of Open Science principles has been a prevalent topic in the welding science community over the last years. Providing access to welding knowledge in the form of complex and complete datasets in addition to peer-reviewed publications can be identified as an important step to promote knowledge exchange and cooperation. There exist previous efforts on building data models specifically for fusion welding applications; however, a common agreed upon implementation that is used by the community is still lacking. One proven approach in other domains has been the use of an openly accessible and agreed upon file and data format used for archiving and sharing domain knowledge in the form of experimental data. Going into a similar direction, the welding community faces particular practical, technical, and also ideological challenges that are discussed in this paper. Collaboratively building upon previous work with modern tools and platforms, the authors motivate, propose, and outline the use of a common file format specifically tailored to the needs of the welding research community as a complement to other already established Open Science practices. Successfully establishing a culture of openly accessible research data has the potential to significantly stimulate progress in welding research.
KW - Welding
KW - Research data management
KW - Open science
KW - Digitalization
KW - Weldx
KW - Open source
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529332
DO - https://doi.org/10.1007/s40194-021-01151-x
SN - 1878-6669
SN - 0043-2288
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-52933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tatzel, Michael
A1 - Oelze, Marcus
A1 - Frick, Daniel A.
A1 - Di Rocco, Tommaso
A1 - Liesegang, Moritz
A1 - Stuff, Maria
A1 - Wiedenbeck, Michael
T1 - Silicon and oxygen isotope fractionation in a silicified carbonate rock
N2 - Silicon isotope fractionation during silicification is poorly understood and impedes our ability to decipher paleoenvironmental conditions from Si isotopes in ancient cherts. To investigate isotope fractionation during silica-for-carbonate replacement we analyzed the microscale Si and O isotope composition in different silica phases in a silicified zebra dolostone as well as their bulk δ18O and Δ’17O compositions. The subsequent replacement of carbonate layers is mimicked by decreasing δ18O and δ30Si. The textural relationship and magnitude of Si and O isotope fractionation is best explained by near-quantitative silica precipitation in an open system with finite Si. A Rayleigh model for silicification suggests positive Ɛ30/28Si during silicification, conforming with predictions for isotope distribution at chemical equilibrium from ab-initio models. Application of the modelled Ɛ30Si-T relationship yields silicification temperatures of approx. 50°C. To reconcile the δ18Ochert composition with these temperatures, the δ18O of the fluid must have been between -2.5 and -4 ‰, compositions for which the quartz phases fall close to the oxygen equilibrium fractionation line in three-isotope space. Diagenetic silica replacement appears to occur in O and Si isotopic equilibrium allowing reconstructions of temperatures of silicification from Si isotopes and derive the δ18O composition of the fluid – a highly desired value needed for accurate reconstructions of the temperature- and δ18O histories of the oceans.
KW - Silicon isotopes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603430
DO - https://doi.org/10.1016/j.chemgeo.2024.122120
SN - 0009-2541
VL - 658
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Häßler, Dustin
A1 - Mund, Maximilian
A1 - Daus, Lars-Hendrik
A1 - Hothan, Sascha
A1 - Schaumann, Peter
A1 - Schartel, Bernhard
T1 - Durability of intumescent coatings and recommendations for test concepts for a working life of more than 10 years
N2 - It is an essential requirement for all building products to ensure durability of their fire safety. Throughout the working life of products, intumescent coatings are aged by certain climatic factors. To predict a lifetime of several years, generally the behaviour of the intumescent coating is extrapolated based on accelerated artificial ageing. The established German and European procedures to assess the durability assume a working life of at least 10 years. For a longer period, additional evidence is required; yet the procedure and the specifications to justify this are not described. In addition to addressing this formal lack, from a scientific point of view it is necessary to investigate the degradation of intumescent coatings in detail and to propose a reliable test concept to assess durability for more than 10 years. This paper summarises the existing knowledge about the ageing of intumescent coatings. The results of various demanding weathering approaches are presented for two intumescent coatings tested in a joint research project. Moreover, formulations with a reduced amount of functionally relevant components were analysed to gain insight into the associated effects. Derived from these research results and knowledge, recommendations are proposed to assess the durability of intumescent coatings for more than 10 years based on a combination of verifications.
KW - Ageing
KW - Fire protection
KW - Intumescent coating
KW - Steel construction
KW - Working life
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603852
DO - https://doi.org/10.1016/j.firesaf.2024.104173
SN - 0379-7112
VL - 146
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-60385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schuberth, Jens
A1 - Ebert, Thomas
A1 - Schlegel, Moritz-Caspar
A1 - Rödig, Lisa
A1 - Jepsen, Dirk
A1 - Memelink, Robin
A1 - Hauschke, Fynn
T1 - The Front-Runner Approach - Facilitating Progressive Product Policy by Using Information from EU Product Databases
N2 - The European Commission has recently announced two guiding principles for EU product policy: First, product policy shall ensure that the performance of front-runner products in terms of sustainability becomes the norm, and second, the effectiveness of the current Ecodesign legislative framework is going to be significantly improved. Within this paper, already existing front-runner approaches and recent and ongoing product policy-making processes were reviewed. Based on the results, an EU front-runner approach is outlined. The presented approach (i) refers to performance levels of the best products already available on the market, (ii) aggregates information in existing databases, and (iii) works semi-automated. Together, all three attributes have a high potential to facilitate and accelerate the specification of appropriate minimum requirements for products at the EU level. This way, EU policymakers can deliver on the core objectives of the Ecodesign legislative framework much better. The basic mechanism and its legal entrenchment of the approach are illustrated for the energy efficiency of energy-related products. In addition, the Front-Runner Approach can be applied to any product group in the scope of the upcoming Ecodesign for Sustainable Products Regulation and to a wide range of product-related minimum requirements, such as durability, reparability, or recycled content. The study’s objective is to suggest a tailor-made and dynamic approach to keep the EU product legislation up to date using innovative technology based on the investigation of current regulations and identify the gap. Experiences from three international case studies suggest that a front-runner approach to setting energy-performance standards can drive innovation and reduce energy consumption via promoting energy-efficient products; transparency about available products is one of the key factors and can be established by a database. The EU front-runner approach comprises extending the existing energy label database (or making use of the digital product passport) and introducing a legislative procedure that triggers changes in the energy efficiency requirements in the specific EU regulations if the database shows that a certain threshold value is reached. Challenges such as limited EU staff capacities and opportunities such as increased dynamic are discussed.
KW - Ecodesign
KW - ESPR
KW - Energy labelling
KW - EPREL
KW - Policy making
KW - Front-runner
KW - Material efficiency
KW - Resource efficiency
KW - Energy efficiency
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595132
DO - https://doi.org/10.3390/en17020504
VL - 17
IS - 2
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-59513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Guerra, M.F.
A1 - Martinón-Torres, M.
A1 - Lemasson, Q.
A1 - Moignard, B.
A1 - Pacheco, C.
A1 - Pichon, L.
A1 - Macdonald, L.
A1 - Hess, M.
A1 - Tissot, I.
ED - Guerra, M. F.
ED - Martinón-Torres, M.
ED - Quirke, S.
T1 - Analytical approaches to Egyptian goldwork
N2 - The structure and composition of ancient gold objects retain information about their long history of manufacture, from the exploitation of the ore to the finishing touches, as well as evidence of their use, deposition, and degradation. By developing an efficient analytical strategy, it is possible to retrieve that information. This chapter sets the necessary foundation 131to explore fully the analytical results presented in the following chapters of this volume. The techniques employed in the analyses of the Egyptian jewellery are described and the analytical parameters provided. For more established techniques, only brief introductions are presented, while more recent developments are presented in greater detail.
KW - Gold
KW - Synchrotron
KW - D2XRF
KW - Egypt
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586039
DO - https://doi.org/10.17863/CAM.99681
SP - 131
EP - 191
AN - OPUS4-58603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials
N2 - An in-depth insight into the chemistry and nature of the individual chemical bonds is essential for understanding materials. Bonding analysis is thus expected to provide important features for large-scale data analysis and machine learning of material properties. Such chemical bonding information can be computed using the LOBSTER software package, which post-processes modern density functional theory data by projecting the plane wave-based wave functions onto an atomic orbital basis. With the help of a fully automatic workflow, the VASP and LOBSTER software packages are used to generate the data. We then perform bonding analyses on 1520 compounds (insulators and semiconductors) and provide the results as a database. The projected densities of states and bonding indicators are benchmarked on standard density-functional theory computations and available heuristics, respectively. Lastly, we illustrate the predictive power of bonding descriptors by constructing a machine learning model for phononic properties, which shows an increase in prediction accuracies by 27% (mean absolute errors) compared to a benchmark model differing only by not relying on any quantum-chemical bonding features.
KW - Bonding Analysis
KW - DFT
KW - High-throughput
KW - Database
KW - Phonons
KW - Machine Learning
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582892
DO - https://doi.org/10.1038/s41597-023-02477-5
VL - 10
IS - 1
SP - 1
EP - 18
AN - OPUS4-58289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash Ashok
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - Jackson, Adam J.
A1 - George, Janine
T1 - LobsterPy: A package to automatically analyze LOBSTERruns
N2 - The LOBSTER (Deringer et al., 2011;Maintz et al., 2013 ,2016 ;Nelson et al., 2020 ) software aids in extracting quantum-chemical bonding information from materials by projecting the plane-wave based wave functions from density functional theory (DFT) onto an atomic orbital basis. LobsterEnv, a module implemented in pymatgen (Ong et al., 2013) by some of the authors of this package, facilitates the use of quantum-chemical bonding information obtained from LOBSTER calculations to identify neighbors and coordination environments. LobsterPy is a Python package that offers a set of convenient tools to further analyze and summarize the LobsterEnv outputs in the form of JSONs that are easy to interpret and process. These tools enable the estimation of (anti) bonding contributions, generation of textual descriptions, and visualization of LOBSTER computation results. Since its first release, both LobsterPy and LobsterEnv capabilities have been extended significantly. Unlike earlier versions, which could only automatically analyze Crystal Orbital Hamilton Populations (COHPs) (Dronskowski & Blöchl, 1993), both can now also analyze Crystal Orbital Overlap Populations (COOP) (Hughbanks & Hoffmann, 1983) and Crystal Orbital Bond Index (COBI) (Müller et al., 2021). Extracting the information about the most important orbitals contributing to the bonds is optional, and users can enable it as needed. Additionally, bonding-based features for machinelearning (ML) studies can be engineered via the sub-packages “featurize” and “structuregraphs”. Alongside its Python interface, it also provides an easy-to-use command line interface (CLI) that runs automatic analysis of the computations and generates a summary of results and publication-ready figures. LobsterPy has been used to produce the results in Ngo et al. (2023), Chen et al. (2024), Naik et al. (2023), and it is also part of Atomate2 (2023) bonding analysis workflow for generating bonding analysis data in a format compatible with the Materials Project (Jain et al., 2013) API.
KW - Materials Science
KW - Automation
KW - Bonding Analysis
KW - Materials Properties
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595809
DO - https://doi.org/10.21105/joss.06286
VL - 9
IS - 94
SP - 1
EP - 4
PB - The Open Journal
AN - OPUS4-59580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
N2 - We present Jobflow, a domain-agnostic Python package for writing computational workflows tailored for high-throughput computing applications. With its simple decorator-based approach, functions and class methods can be transformed into compute jobs that can be stitched together into complex workflows. Jobflow fully supports dynamic workflows where the full acyclic graph of compute jobs is not known until runtime, such as compute jobs that launch
other jobs based on the results of previous steps in the workflow. The results of all Jobflow compute jobs can be easily stored in a variety of filesystem- and cloud-based databases without the data storage process being part of the underlying workflow logic itself. Jobflow has been intentionally designed to be fully independent of the choice of workflow manager used to dispatch the calculations on remote computing resources. At the time of writing, Jobflow
workflows can be executed either locally or across distributed compute environments via an adapter to the FireWorks package, and Jobflow fully supports the integration of additional workflow execution adapters in the future.
KW - Automation
KW - Workflow
KW - Computational Materials Science
KW - Computations
KW - Software
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593104
DO - https://doi.org/10.21105/joss.05995
VL - 9
IS - 93
SP - 1
EP - 7
PB - The Open Journal
AN - OPUS4-59310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Nondestructive thermographic detection of internal defects using pixel-pattern based laser excitation and photothermal super resolution reconstruction
N2 - In this work, we present a novel approach to photothermal super resolution based thermographic resolution of internal defects using two-dimensional pixel pattern-based active photothermal laser heating in conjunction with subsequent numerical reconstruction to achieve a high-resolution reconstruction of internal defect structures. With the proposed adoption of pixelated patterns generated using laser coupled high-power DLP projector technology the complexity for achieving true two-dimensional super resolution can be dramatically reduced taking a crucial step forward towards widespread practical viability. Furthermore, based on the latest developments in high-power DLP projectors, we present their first application for structured pulsed thermographic inspection of macroscopic metal samples. In addition, a forward solution to the underlying inverse problem is proposed along with an appropriate heuristic to find the regularization parameters necessary for the numerical inversion in a laboratory setting. This allows the generation of synthetic measurement data, opening the door for the application of machine learning based methods for future improvements towards full automation of the method. Finally, the proposed method is experimentally validated and shown to outperform several established conventional thermographic testing techniques while conservatively improving the required measurement times by a factor of 8 compared to currently available photothermal super resolution techniques.
KW - Thermography
KW - Super resolution
KW - NDT
KW - Inspection
KW - Internal defects
KW - DMD
KW - DLP
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570551
DO - https://doi.org/10.1038/s41598-023-30494-2
SN - 2045-2322
VL - 13
SP - 1
EP - 13
PB - Nature Research
AN - OPUS4-57055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
ED - Maldague, X.
T1 - Detection of internal defects applying photothermal super resolution reconstruction utilizing two-dimensional high-power random pixel patterns
N2 - In this work, we report on our progress for investigating a new experimental approach for thermographic detection of internal defects by performing 2D photothermal super resolution reconstruction. We use modern high-power laser projector technology to repeatedly excite the sample surface photothermally with varying spatially structured 2D pixel patterns. In the subsequent (blind) numerical reconstruction, multiple measurements are combined by exploiting the joint-sparse nature of the defects within the specimen using nonlinear convex optimization methods. As a result, a 2D-sparse defect/inhomogeneity map can be obtained. Using such spatially structured heating combined with compressed sensing and computational imaging methods allows to significantly reduce the experimental complexity and to study larger test surfaces as compared to the one-dimensional approach reported earlier.
T2 - Quantitative Infrared Thermography 2022
CY - Paris, France
DA - 04.07.2022
KW - Thermography
KW - Super resolution
KW - NDT
KW - inspection
KW - Internal defects
KW - DMD
KW - DLP
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577795
DO - https://doi.org/10.21611/qirt.2022.1005
SN - 2371-4085
SP - 1
EP - 7
PB - QIRT Council
AN - OPUS4-57779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - The MOUSE project - A meticulous approach for obtaining traceable, wide-range X-ray scattering information
N2 - Herein, we provide a "systems architecture"-like overview and detailed discussions of the methodological and instrumental components that, together, comprise the "MOUSE" project (Methodology Optimization for UltrafineStructure Exploration). The MOUSE project provides scattering information on a wide variety of samples, with traceable dimensions for both the scattering vector (q) and the absolute scattering cross-section (I). The measurable scattering vector-range of 0.012≤ q (nm-1) ≤ 92, allows information across a hierarchy of structures with dimensions ranging from ca. 0.1 to 400 nm. In addition to details that comprise the MOUSE project, such as the organisation and traceable aspects, several representative examples are provided to demonstrate its flexibility. These include measurements on alumina membranes, the tobacco mosaic virus, and dual-source information that overcomes fluorescence limitations on ZIF-8 and iron-oxide-containing carbon catalyst materials.
KW - X-ray scattering
KW - MOUSE
KW - Instrumentation
KW - SAXS
KW - Methodology
KW - Traceability
KW - Wide-range
KW - Data curation
KW - FAIR
KW - Uncertainties
KW - Nanomaterials
KW - Nanometrology
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528669
DO - https://doi.org/10.1088/1748-0221/16/06/P06034
VL - 16
IS - 6
SP - 1
EP - 50
PB - IOP
CY - Bristol, UK
AN - OPUS4-52866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Annadurai, V.
A1 - Balazs, D. M.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Del Giudice, A.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Garcia, P. R. A. F.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, M.
A1 - Hollamby, M.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Rochels, L.
A1 - Rosalie, Julian M.
A1 - Saloga, Patrick E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz M.
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round Robin
KW - Data analysis
KW - Small-angle scattering
KW - Nanomaterials
KW - Interlaboratory comparability
KW - Nanostructure quantification
KW - Methodology
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587091
DO - https://doi.org/10.1107/S1600576723008324
SN - 1600-5767
VL - 56
IS - 6
SP - 1618
EP - 1629
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Campari, Alessandro
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Alvaro, Antonio
T1 - A comparison of vintage and modern X65 pipeline steel using hollow specimen technique for in-situ hydrogen testing
N2 - The transition toward a hydrogen-based economy requires a widespread transport and distribution network, and repurposed natural gas pipelines are a viable option. An assessment of the hydrogen-induced degradation of pipeline steels is needed to inject H2 gas into the existing infrastructure safely. The conservative and standardized method consists of in-situ tensile tests in an autoclave filled with high-pressure hydrogen gas. A proposed alternative method involves
using a hollow specimen as containment volume and applying the gas pressure in the inner cavity.
This technique has lower costs and shorter test preparation time but is not standardized yet. This study aims to evaluate and compare the tensile properties of API 5L X65 pipeline steel in two states: vintage and modern. The influence of the surface roughness is investigated through parallel tests with drilled and reamed specimens. Hydrogen tests are compared with reference tests in an inert environment. A significant hydrogen-induced decrease in tensile properties is observed, and no significant difference between vintage and modern X65 can be drawn. The reduction in tensile properties is more significant in specimens with higher inner surface roughness. The evaluation of surface conditions appears crucial when assessing the HE susceptibility of hydrogen transport and storage equipment.
KW - Hydrogen embrittlement
KW - Hollow specimen technique
KW - Pipeline steel
KW - SSRT
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603013
DO - https://doi.org/10.1016/j.engfailanal.2024.108530
VL - 163
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-60301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rauwolf, M.
A1 - Turyanskaya, A.
A1 - Roschger, A.
A1 - Prost, J.
A1 - Simon, R.
A1 - Scharf, O.
A1 - Radtke, Martin
A1 - Schoonjans, Tom
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Klaushofer, K.
A1 - Wobrauschek, P.
A1 - Hofstaetter, J. G.
A1 - Roschger, P.
A1 - Streli, C.
T1 - Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups
N2 - In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-mXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its K alpha XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution.
KW - Synchrotron
KW - BAMline
KW - BESSY
KW - XRF
KW - X-ray Color Camera
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391944
DO - https://doi.org/10.1107/S1600577516017057
SN - 1600-5775
VL - 24
SP - 307
EP - 311
PB - International Union of Crystallography
AN - OPUS4-39194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arnold, M.
A1 - Katzmann, J.
A1 - Naik, Aakash Ashok
A1 - Görne, A. L.
A1 - Härtling, Thomas
A1 - George, Janine
A1 - Schuster, C.
T1 - Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: Evidence for and DFT simulation of a radiation-induced phase
N2 - A recent approach to measure electron radiation doses in the kGy range is the use of phosphors with an irradiation dose-dependent luminescence decay time. However, the applicability of the previously investigated material NaYF4:Yb3+,Er3+ is limited as it shows pronounced fading. Therefore, in this work, a modified SrF2 synthesis is presented that results in SrF2 nanoparticles codoped with Yb and either Er, Hm, or Tm. To assess their suitability as dosimeter material, dose response, as well as its degree of fading over 50 up to 140 days after irradiation were measured. Fading rates as small as 5% in SrF2:Er,Yb and 4% in SrF2:Ho,Yb were derived, which are comparable to established dosimeter materials. A combination of spectroscopy, diffraction and DFT calculations was used to elucidate the effect of irradiation, pointing towards the formation of a secondary phase of Yb2+ that we predict could be Yb2OF2. This irreversible formation of a secondary phase is considered to be the explanation for the low fading behavior in SrF2-based phosphors compared to NaYF4:Yb, Er, a highly attractive feature for electron beam dosimetry.
KW - DFT
KW - Structure prediction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554115
DO - https://doi.org/10.1039/D2TC01773C
SN - 2050-7526
VL - 10
IS - 32
SP - 11579
EP - 11587
PB - RSC
CY - London
AN - OPUS4-55411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nowak, S.H.
A1 - Bjeoumikhov, A.
A1 - Von Borany, J.
A1 - Buchriegler, J.
A1 - Munnik, F.
A1 - Petric, M.
A1 - Radtke, Martin
A1 - Renno, A.D.
A1 - Reinholz, Uwe
A1 - Scharf, O.
A1 - Wedell, R.
T1 - Sub-pixel resolution with a color X-ray camera
N2 - The color X-ray camera SLcam® is a full-field, single photon detector providing scanning-free, energy and spatially resolved X-ray imaging. Spatial resolution is achieved with the use of polycapillary optics guiding X-ray photons from small regions on a sample to distinct energy dispersive pixels on a charged-coupled device detector. Applying sub-pixel resolution, signals from individual capillary channels can be distinguished. Therefore, the SLcam® spatial resolution, which is normally limited to the pixel size of the charge-coupled device, can be improved to the size of individual polycapillary channels. In this work a new approach to a sub-pixel resolution algorithm comprising photon events also from the pixel centers is proposed. The details of the employed numerical method and several sub-pixel resolution examples are presented and discussed.
KW - Color X-ray camera
KW - Sub pixel analysis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334948
DO - https://doi.org/10.1039/c5ja00028a
SN - 0267-9477
SN - 1364-5544
SP - 1890
EP - 1897
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-33494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Gluth, Gregor
A1 - Mittermayr, F.
A1 - Ukrainczyk, N.
A1 - Bertmer, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Leis, A.
A1 - Dietzel, M.
T1 - Deterioration mechanism of alkali-activated materials in sulfuric acid and the influence of Cu: A micro-to-nano structural, elemental and stable isotopic multi-proxy study
N2 - In this study, a multi-proxy approach combining 29Si, 27Al and 1H MAS-NMR, FEG-EPMA, XANES at the Cu K-edge and XRD analytics with hydrochemical tools such as ICP-OES analyses, oxygen-isotope signatures, and thermodynamic modelling was applied to K-silicate-activated metakaolin specimens - with and without CuSO4·5H2O addition - exposed to sulfuric acid at pH = 2 for 35 days. The results revealed a multistage deterioration mechanism governed by (i) acid diffusion, (ii) leaching of K-A-S-H, (iii) microstructural damage related to precipitation of expansive (K,Ca,Al)-sulfate-hydrate phases (iv) complete dissolution of the K-A-S-H framework, (v) and formation of silica gel in the outermost corroded regions. Copper ions were mainly located in layered spertiniite-chrysocolla-like phases in the as-cured materials. The results demonstrate an overall negative effect of Cu addition on chemical material durability, implying that the reported higher durability of Cu-doped AAM in biocorrosion environments can be best explained by bacteriostatic effects.
KW - Alkali-activated materials
KW - Acid resistance
KW - Microbially induced corrosion
KW - MIC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520567
DO - https://doi.org/10.1016/j.cemconres.2021.106373
SN - 0008-8846
VL - 142
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-52056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadi, Samim
A1 - Thummerer, G.
A1 - Breitwieser, S.
A1 - Mayr, G.
A1 - Lecompagnon, Julien
A1 - Burgholzer, P.
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
T1 - Multi-dimensional reconstruction of internal defects in additively manufactured steel using photothermal super resolution combined with virtual wave based image processing
N2 - We combine three different approaches to greatly enhance the defect reconstruction ability of active thermographic testing. As experimental approach, laser-based structured illumination is performed in a step-wise manner. As an intermediate signal processing step, the virtual wave concept is used in order to effectively convert the notoriously difficult to solve diffusion-based inverse problem into a somewhat milder wavebased inverse problem. As a final step, a compressed-sensing based optimization procedure is applied which efficiently solves the inverse problem by making advantage of the joint sparsity of multiple blind measurements. To evaluate our proposed processing technique, we investigate an additively manufactured stainless steel sample with eight internal defects. The concerted super resolution approach is compared to conventional thermographic reconstruction techniques and shows an at least four times better spatial resolution.
KW - Active thermography
KW - Additive manufacturing
KW - Stainless steel
KW - ADMM
KW - Block regularization
KW - Internal defects
KW - Joint sparsity
KW - Laser excitation
KW - Multi-dimensional reconstruction
KW - Photothermal super resolution
KW - Virtual waves
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525330
DO - https://doi.org/10.1109/tii.2021.3054411
SN - 1551-3203
SN - 1941-0050
VL - 17
IS - 11
SP - 7368
EP - 7378
PB - IEEE
CY - New York, NY
AN - OPUS4-52533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lutz, C.
A1 - Breuckmann, M.
A1 - Hampel, S.
A1 - Kreyenschmidt, M.
A1 - Ke, X.
A1 - Beuermann, S.
A1 - Schafner, K.
A1 - Turek, T.
A1 - Kunz, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Fittschen, U. E. A.
T1 - Characterization of Dimeric Vanadium Uptake and Species in Nafion™ and Novel Membranes from Vanadium Redox Flow Batteries Electrolytes
N2 - A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based Membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a
better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing Vdimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that Vdimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the Vdimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane.
The Vdimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO3
) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > Vdimer(IV–V) [λ = 0.039]. The results show that the Vdimer(IV–V) dimer Needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.
KW - MicroXRF
KW - VRFB
KW - PVDF-based membrane
KW - UV/VIS
KW - XANES
KW - TXRF
KW - ICP-OES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530676
DO - https://doi.org/10.3390/membranes11080576
VL - 11
IS - 8
SP - 576
PB - MDPI
AN - OPUS4-53067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guerra, M. F.
A1 - Fischer, M.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
T1 - Inca figurines from the Ethnologisches Museum in Berlin: an analytical study of some typical and atypical productions
N2 - Fourteen hollow and one cast anthropomorphic and zoomorphic figurines produced in Incan times for ritual offerings from the Ethnologisches Museum in Berlin were selected to investigate the technologies and alloys used for their fabrication with portable optical microscopy and non-destructive XRF elemental analysis. This group of gold and silver figurines includes typical specimens of the Inca production, such as the four silver figurines from the Island Coati in Lake Titicaca and the two gold figurines from Pachacamac, as well as specimens that are seldom present in collections, which makes them atypical. In addition to the tall figurines with atypical hair or standing pose, one bicolour figurine half silver, half gold) and another with coloured inlays were included in this study for comparison. The large majority of the silver specimens are made from very high quality alloys and the gold figurines are made from alloys containing low copper contents and silver ranging from 30wt% to 52wt%.
KW - Gold
KW - pXRF
KW - Inca
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436015
DO - https://doi.org/10.4000/bifea.8232
SN - 0303-7495
VL - 46
IS - 1
SP - 221
EP - 251
PB - Institut Français d'Études Andines
AN - OPUS4-43601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Oliver
A1 - Denker, A.
A1 - Merchel, S.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Wolff, T.
ED - Armbruster, B.
ED - Eilbracht, H.
ED - Hahn, Oliver
ED - Heinrich-Tamaska, O.
T1 - Zerstörungsfreie Analyse von Metallartefakten - Eine Fallstudie
N2 - Die naturwissenschaftliche Analyse historischer Materialen ermöglicht die Beantwortung kulturhistorischer Fragestellungen, die mit kunsthistorischen oder archäologischen Ansätzen allein nicht zu leisten sind. In dieser Studie wurden sechs römische Münzen mit unterschiedlich stark ausgeprägten Korrosionsschichten an unbehandelten und polierten Stellen mit vier zerstörungsfreien analytischen Methoden untersucht: Hoch- und Niederenergie Protonen Induzierter Röntgenemission (HE-/PIXE), Synchrotronstrahlungsinduzierte-Röntgenfluoreszenzanalyse (SY-RFA) und Mikro-Röntgenfluoreszenzanalyse (Mikro-RFA) mit einem mobilen Gerät. Aufgrund von Unterschieden in den Messbedingungen und dem Einfluss der Patina-Schichten auf diese ergaben sich nur für wenige Elemente Übereinstimmungen in den quantitativen Daten. Zur Validierung zukünftiger Messkampagnen mit verschiedenen Methoden sind daher Vergleichstudien unerlässlich.
N2 - Investigations of physical properties and chemical composition of ancient materials generate important data for answering culture-historical questions that cannot be solved by art historical and archaeological methods alone. This contribution reports on the analysis of six Roman coins, with different degrees of corrosion layers in parts that were not handled or polished, using four non-destructive methods: low-energy particle-induced X-ray emission (PIXE, 2 MeV), high-energy PIXE (68 MeV), μ-X-ray fluorescence (XRF) spectrometry with a portable device and synchrotron-radiation induced XRF. Because of differences in the conditions needed for measurement and the influence of the layers of patina on these measurements, there were few elements where the quantitative data were in agreement. Thus comparative analyses are essential to validate future measurement projects using different methods.
KW - Zerstörungsfreie Prüfung
KW - Protoneninduzierte Röntgenemission
KW - Röntgenfluoreszenzanalyse
KW - Non-destructive testing
KW - Particle-induced X-ray emission
KW - X-ray fluorescence analysis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-385702
SN - 978-3-9816751-5-3
VL - Berlin studies of the ancient world, Band 35
SP - 117
EP - 137
PB - Edition Topoi
CY - Berlin
AN - OPUS4-38570
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, L.
A1 - Ahmadi, Samim
A1 - Jonietz, Florian
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
A1 - Lambrecht, J.
T1 - Classification of Spot-Welded Joints in Laser Thermography Data Using Convolutional Neural Networks
N2 - Spot welding is a crucial process step in various industries. However, classification of spot welding quality is still a tedious process due to the complexity and sensitivity of the test material, which drain conventional approaches to its limits. In this article, we propose an approach for quality inspection of spot weldings using images from laser thermography data. We propose data preparation approaches based on the underlying physics of spot-welded joints, heated with pulsed laser thermography by analyzing the intensity over time and derive dedicated data filters to generate training datasets. Subsequently, we utilize convolutional neural networks to classify weld quality and compare the performance of different models against each other. We achieve competitive results in terms of classifying the different welding quality classes compared to traditional approaches, reaching an accuracy of more than 95 percent. Finally, we explore the effect of different augmentation methods.
KW - Active thermal imaging
KW - Laser thermography
KW - Spot-welded joints
KW - Convolutional neural network
KW - Classification
KW - Data processing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524216
DO - https://doi.org/10.1109/ACCESS.2021.3063672
VL - 9
SP - 48303
EP - 48312
AN - OPUS4-52421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Rakotondrajoa, A.
T1 - Machine learning based quantification of synchrotron radiation-induced X-ray fluorescence measurements - a case study
N2 - In this work, we describe the use of artificial neural networks for the quantification of X-ray fluorescence measurements. The training data were generated using Monte Carlo simulation, which avoided the use of adapted reference materials. The extension of the available data set by means of an ANN to generate additional data was demonstrated. Particular emphasis was put on the comparability of simulated and experimental data and how the influence of deviations can be reduced. The search for the optimal hyperparameter, manual and automatic, is also described. For the presented case, we were able to train a network with a mean absolute error of 0.1 weight percent for the synthetic data and 0.7 weight percent for a set of experimental data obtained with certified reference materials.
KW - Machine learning
KW - BAMline
KW - XRF
KW - Synchrotron
KW - Neural network
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519008
DO - https://doi.org/10.1088/2632-2153/abc9fb
SP - 1
EP - 16
PB - IOP Publishing
AN - OPUS4-51900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Ziegler, Mathias
T1 - Detection of surface breaking cracks using flying line laser thermography: A Canny-based algorithm
N2 - In this work, we introduce a new algorithm for effectual crack detection using flying line laser thermography, based on the well-known Canny approach. The algorithm transforms the input thermographic sequence into an edge map. Experimental measurements are performed on a metallic component that contains surface breaking cracks due to industrial use. The specimen is tested using flying line thermography at different scanning speeds and laser input powers. Results obtained with the proposed algorithm are additionally compared with a previously established algorithm for flying spot thermography. The proposed Canny-based algorithm can be used in automated systems for thermographic non-destructive testing.
T2 - Advanced Infrared Technology and Applications 2021
CY - Online meeting
DA - 26.10.2021
KW - Canny approach
KW - Flying line thermography
KW - Crack detection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539628
DO - https://doi.org/10.3390/engproc2021008022
SN - 2673-4591
VL - 8
IS - 1
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-53962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Avila Calderon, Luis
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
KW - Creep
KW - Computed Tomography
KW - PBF-LB/M/316L
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - AISI 316L
KW - Additive Manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574127
DO - https://doi.org/10.1002/adem.202201581
SP - 1
EP - 9
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Polatidis, E.
A1 - Čapek, J.
A1 - Mohr, Gunther
A1 - Serrano Munoz, Itziar
A1 - Bruno, Giovanni
T1 - Understanding the impact of texture on the micromechanical anisotropy of laser powder bed fused Inconel 718
N2 - The manufacturability of metallic alloys using laser-based additive manufacturing methods such as laser powder bed fusion has substantially improved within the last decade. However, local melting and solidification cause hierarchically structured and crystallographically textured microstructures possessing large residual stress. Such microstructures are not only the origin of mechanical anisotropy but also pose metrological challenges for the diffraction-based residual stress determination. Here we demonstrate the influence of the build orientation and the texture on the microstructure and consequently the mechanical anisotropy of as-built Inconel 718. For this purpose, we manufactured specimens with [001]/[011]-, [001]- and [011]/[111]-type textures along their loading direction. In addition to changes in the Young’s moduli, the differences in the crystallographic textures result in variations of the yield and ultimate tensile strengths. With this in mind, we studied the anisotropy on the micromechanical scale by subjecting the specimens to tensile loads along the different texture directions during in situ neutron diffraction experiments. In this context, the response of multiple lattice planes up to a tensile strain of 10% displayed differences in the load partitioning and the residual strain accumulation for the specimen with [011]/[111]-type texture. However, the relative behavior of the specimens possessing an [001]/[011]- and [001]-type texture remained qualitatively similar. The consequences on the metrology of residual stress determination methods are discussed.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Electron backscatter diffraction
KW - Tensile testing
KW - Diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555840
DO - https://doi.org/10.1007/s10853-022-07499-9
SN - 1573-4803
VL - 2022
IS - 57
SP - 15036
EP - 15058
PB - Springer Science + Business Media B.V.
CY - Dordrecht
AN - OPUS4-55584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Malpass-Evans, R.
A1 - McKeown, N.
A1 - Jalarvo, N.
A1 - Tyagi, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering – bend fluctuations and signature of methyl group rotation
N2 - Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer–Emmett–Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bendand-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EATB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure.
KW - Polymers of Intrinsic Microporosity
KW - Neutron Scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604114
DO - https://doi.org/10.1039/d4sm00520a
SP - 1
EP - 11
PB - RSC
AN - OPUS4-60411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Bruno, Giovanni
A1 - Hilgenberg, Kai
T1 - Towards a Methodology for Component Design of Metallic AM Parts Subjected to Cyclic Loading
N2 - The safe fatigue design of metallic components fabricated by additive manufacturing (AM) is still a largely unsolved problem. This is primarily due to (a) a significant inhomogeneity of the material properties across the component; (b) defects such as porosity and lack of fusion as well as pronounced surface roughness of the asuilt components; and (c) residual stresses, which are very often present in the as‐built parts and need to be removed by post‐fabrication treatments. Such morphological and microstructural features are very different than in conventionally manufactured parts and play a much bigger role in determining the fatigue life. The above problems require specific solutions with respect to the identification of the critical (failure) sites in AM fabricated components. Moreover, the generation of representative test specimens characterized by similar temperature cycles needs to be guaranteed if one wants to reproducibly identify the critical sites and establish fatigue assessment methods taking into account the effect of defects on crack initiation and early propagation. The latter requires fracture mechanics‐based approaches which, unlike common methodologies, cover the specific characteristics of so‐called short fatigue cracks. This paper provides a discussion of all these aspects with special focus on components manufactured by laser powder bed fusion (L‐PBF). It shows how to adapt existing solutions, identifies fields where there are still gaps, and discusses proposals for potential improvement of the damage tolerance design of L‐PBF components
KW - L‐PBF
KW - Fatigue
KW - Fracture
KW - Defects
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525822
DO - https://doi.org/10.3390/met11050709
VL - 11
IS - 5
SP - 709
PB - MDPI
CY - Basel
AN - OPUS4-52582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis Alexander
A1 - Rehmer, Birgit
A1 - Schriever, Sina
A1 - Ulbricht, Alexander
A1 - Agudo Jácome, Leonardo
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
A1 - Evans, Alexander
T1 - Creep and creep damage behavior of stainless steel 316L manufactured by laser powder bed fusion
N2 - This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism.
KW - 316L
KW - Laser Powder Bed Fusion (LPBF)
KW - Creep behavior
KW - Additive Manufacturing
KW - AGIL
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539373
DO - https://doi.org/10.1016/j.msea.2021.142223
SN - 0921-5093
VL - 830
SP - 142223
PB - Elsevier B.V.
AN - OPUS4-53937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Chaudry, Mohsin Ali
A1 - Scheuschner, Nils
A1 - Blasón Gonzalez, Sergio
A1 - Madia, Mauro
A1 - Hilgenberg, Kai
T1 - Thermal history transfer from complex components to representative test specimens in laser powder bed fusion
N2 - Additively manufactured components are characterized by heterogeneous mechanical properties due to variations of the microstructure, flaws and residual stresses resulting from the inhomogeneous fabrication process. The large number of influencing factors poses a further challenge in understanding the correlation between material properties, process parameters and component geometry. Therefore, the qualification of components based on witness specimens produced within the same job is questionable. This work aims to present a new strategy for the characterization of PBF-LB/M components based on representative specimens. The key assumption is the feasibility of a transfer of the thermal history from a component to a specimen. It is assumed that similar material properties are determined for components and specimens produced adopting a similar thermal history. After the definition of a region of interest in the component, a combination of thermal analyses by means of finite elements and in-situ experimental determination of the thermal history through infrared thermography is used to produce test coupons with a similar thermal history. The effectiveness of the procedure is demonstrated on a pressure vessel for applications in the chemical industry.
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Process simulation
KW - Representative specimens
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602651
DO - https://doi.org/10.1007/s40964-024-00689-8
SN - 2363-9512
SN - 2363-9520
SP - 1
EP - 16
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-60265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - García-González, M.
A1 - Blasón Gonzalez, Sergio
A1 - García-García, I.
A1 - Lamela-Rey, M. J.
A1 - Fernández-Canteli, A.
A1 - Álvarez-Arenal, Á.
T1 - Optimized planning and evaluation of dental implant fatigue testing: A specific software application
N2 - Mechanical complications in implant-supported fixed dental prostheses are often related to implant and prosthetic design. Although the current ISO 14801 provides a framework for the evaluation of dental implant mechanical reliability, strict adherence to it may be difficult to achieve due to the large number of test specimens which it requires as well as the fact that it does not offer any probabilistic reference for determining the endurance limit. In order to address these issues, a new software program called ProFatigue is presented as a potentially powerful tool to optimize fatigue testing of implant-supported prostheses. The present work provides a brief description of some concepts such as load, fatigue and stress-number of cycles to failure curves (S-N curves), before subsequently describing the current regulatory situation. After analyzing the two most recent versions of the ISO recommendation (from 2008 and 2016), some limitations inherent to the experimental methods which they propose are highlighted. Finally, the main advantages and instructions for the correct implementation of the ProFatigue free software are given. This software will contribute to improving the performance of fatigue testing in a more accurate and optimized way, helping researchers to gain a better understanding of the behavior of dental implants in this type of mechanical test.
KW - Dental materials
KW - Prostheses
KW - Implants
KW - Reference standards
KW - Software
KW - Cyclic loading
KW - Fatigue
KW - Lifetime
KW - S-N curve
KW - Staircase method
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516268
DO - https://doi.org/10.3390/biology9110372
SN - 2079-7737
VL - 9
IS - 11
SP - 372-1
EP - 372-12
PB - MDPI
CY - Basel
AN - OPUS4-51626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Guiping
A1 - Liu, Ye
A1 - Schultz, Thorsten
A1 - Exner, Moritz
A1 - Muydinov, Ruslan
A1 - Wang, Hui
A1 - Scheurell, Kerstin
A1 - Huang, Jieyang
A1 - Szymoniak, Paulina
A1 - Pinna, Nicola
A1 - Koch, Norbert
A1 - Adelhelm, Philipp
A1 - Bojdys, Michael J.
T1 - One‐Pot Synthesis of High‐Capacity Sulfur Cathodes via In‐Situ Polymerization of a Porous Imine‐Based Polymer
N2 - AbstractLithium‐ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur‐based cathodes, offering a high theoretical capacity of 1675 mAh g−1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state‐of‐the‐art sulfur‐based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur‘s mobility leads to battery degradation—an effect known as the “sulfur‐shuttle”. This study introduces a solution by developing a microporous, covalently‐bonded, imine‐based polymer network grown in situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li‐ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1 C (1360 mAh g−1) to 3 C (807 mAh g−1). Demonstrating a high‐performance, sustainable sulfur cathode produced via a simple one‐pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal‐based cathodes.
KW - In-situ polymerization
KW - Sulfur cathodes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604215
DO - https://doi.org/10.1002/anie.202400382
SN - 1433-7851
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-60421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Prasenjit
A1 - Chakraborty, Gouri
A1 - Friese, Nico
A1 - Roeser, Jérôme
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Schmidt, Johannes
A1 - Thomas, Arne
T1 - Heteropolyaromatic Covalent Organic Frameworks via One-Pot Multicomponent Reactions
N2 - Multicomponent reactions (MCRs) offer a platform to create different chemical structures and linkages for highly stable covalent organic frameworks (COFs). As an illustrative example, the multicomponent Povarov reaction generates 2,4-phenylquinoline from aldehydes and amines in the presence of electron-rich alkenes. In this study, we introduce a new domino reaction to generate unprecedented 2,3-phenylquinoline COFs in the presence of epoxystyrene. This work thus presents, for the first time, structural isomeric COFs produced by multicomponent domino and Povarov reactions. Furthermore, 2,3-phenylquinolines can undergo a Scholl reaction to form extended aromatic linkages. With this approach, we synthesize two thermally and chemically stable MCR-COFs and two heteropolyaromatic COFs using both domino and in situ domino and Scholl reactions. The structure and properties of these COFs are compared with the corresponding 2,4-phenylquinoline-linked COF and imine-COF, and their activity toward benzene and cyclohexane sorption and separation is investigated. The position of the pendant phenyl groups within the COF pore plays a crucial role in facilitating the industrially important sorption and separation of benzene over cyclohexane. This study opens a new avenue to construct heteropolyaromatic COFs via MCR reactions.
KW - COF
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604038
DO - https://doi.org/10.1021/jacs.4c02551
SP - 1
EP - 9
PB - American Chemical Society (ACS)
AN - OPUS4-60403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill V.
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nicolicea, Alberto
A1 - Oliveros-Mata, E.
A1 - Makarov, D.
A1 - Melzer, Michael
A1 - Pelkner, Matthias
A1 - Zabila, Y.
T1 - Flexible anisotropic magnetoresistive sensors for novel magnetic flux leakage testing capabilities
N2 - Rigid magnetic field sensors such as anisot Hall sensors have been used for years and have become industry standard for electromagnetic non-destructive testing (NDT). Recent technological developments in the field of flexible electronics allow for the fabrication of reshapeable magnetic field sensors on flexible substrates via thin-film deposition or printing. The magnetic properties of these sensors have comparable characteristics to industry-standard rigid magnetic field sensors, with the added ability of adapting to the surface of complex components and scanning in contact with the sample surface. This improves defect detectability and magnetic signal strength by minimizing the scanning lift-off (LO) distance. In this article flexible AMR sensors mounted on a rotative mechanical holder were used to scan a semi-circular ferromagnetic sample with 3 reference defects via magnetic flux leakage (MFL) testing, thus demonstrating the applicability of this type of sensors for the scanning of curved samples. In order to benchmark the performance of these sensors in comparison to industry standard rigid magnetic field sensors, a ferromagnetic sample with 10 reference defects of different depths was scanned employing flexible AMR and rigid GMR sensors. Defects with depths ranging from 110 μm up to 2240 μm were detected with an signal-tonoise ratio (SNR) of 2.7 up to 27.9 (for flexible AMR sensors) and 6.2 up to 72.3 (for rigid GMR sensors), respectively. A 2D magnetometer mapping of the sample with a spatial scanning step of 10 × 50 μm2 (flexible AMR) and 16 × 100 μm2 (rigid GMR) was obtained. The results show that this type of sensor can be used for high-resolution and high-detail mapping of defects on the surface of planar and non-planar ferromagnetic samples since the scanning lift-off distance is equal to the substrate thickness of 20 μm for in-contact scanning. The SNR comparison between flexible and rigid sensors shows that the performance of the flexible AMR sensors employed is not very far behind the performance of the rigid GMR sensors used.
KW - Flexible magnetic field sensors
KW - Non-destructive testing
KW - Magnetic flux leakage
KW - Thin film sensor fabrication
KW - Defect detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603931
DO - https://doi.org/10.1016/j.ndteint.2024.103160
VL - 146
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-60393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Vogel, Christian
A1 - Kalbe, Ute
T1 - Antimony and vanadium in incineration bottom ash – leaching behavior and conclusions for treatment processes
N2 - Due to its large mineral fraction, incineration bottom ash (IBA) from municipal solid waste incineration is an interesting raw material that can be used for road construction or to produce secondary building materials. However, leaching chloride, sulfate, and potentially harmful heavy metals may cause problems in using IBA in civil engineering. Investigating leaching behavior is crucial for the assessment of the environmental compatibility of IBA applications. Various test procedures are available for that purpose. In the present study, a long-term leaching test of a wet-mechanically treated IBA was performed in a lysimeter for almost six years.
While concentrations of chloride, sulfate and the majority of the heavy metals started to decrease rapidly with progressive liquid-to-solid ratio (L/S), antimony (Sb) and vanadium (V) behaved differently. At the beginning of the lysimeter test, the Sb and V concentrations were low, but after approximately one year of operation at an L/S ratio of around 0.8 L/kg, a steady increase was observed. It was shown that this increase is the result of low Ca concentrations due to the formation of CaCO3.
With the data, the solubility products from Ca-antimonate and Ca-vanadate were calculated. The unusual leaching behavior of Sb and V should be kept in mind when considering field scenarios and evaluating the impact on the environment.
KW - Bottom ash
KW - Lysimeter
KW - Leaching of waste materials
KW - Secondary building materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534317
DO - https://doi.org/10.31025/2611-4135/2021.15115
SN - 2611-4135
VL - 16
SP - 75
EP - 81
PB - CISA
CY - Padua
AN - OPUS4-53431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blasenbauer, D.
A1 - Huber, F.
A1 - Lederer, J.
A1 - Quina, M.
A1 - Blanc-Biscarat, D.
A1 - Bogush, A.
A1 - Bontempi, E.
A1 - Blondeau, J.
A1 - Chimenos, J.
A1 - Dahlbo, H.
A1 - Fagerqvist, J.
A1 - Giro-Paloma, J.
A1 - Hjelmar, O.
A1 - Hyks, J.
A1 - Keaney, J.
A1 - Lupsea-Toader, M.
A1 - O’Caollai, C.
A1 - Orupõld, K.
A1 - Pajak, T.
A1 - Simon, Franz-Georg
A1 - Svecova, L.
A1 - Syc, M.
A1 - Uvang, R.
A1 - Vaajasaari, K.
A1 - van Caneghem, J.
A1 - van Zomeren, A.
A1 - Vasarevičius, S.
A1 - Wégner, K.
A1 - Fellner, J.
T1 - Legal situation and current practice of waste incineration bottom ash utilisation in Europe
N2 - Almost 500 municipal solid waste incineration plants in the EU, Norway and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals. Metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. As a result from a cooperation network between European experts an up-to-date overview of documents regulating IBA utilisation is presented. Furthermore, this work highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the emission by leaching are defined. An analysis of the defined parameter reveals that leaching parameters are significantly more to be considered compared to total content parameters. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test (monolithic materials) are in place.
A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. The overall utilisation rate of IBA in construction works is approximately 54 wt%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances.
KW - Bottom ash
KW - Leaching tests
KW - Utilisation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500161
DO - https://doi.org/10.1016/j.wasman.2019.11.031
SN - 0956-053X
VL - 102
SP - 868
EP - 883
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-50016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Kalbe, Ute
T1 - Measurement of the Environmental Impact of Materials
N2 - This Special Issue, ‘Measurement of the Environmental Impact of Materials’, is focused on the impact that materials have on the environmental compartments of soil, water and air. Leaching and emission processes, including underlying mechanisms, are a recurring topic in most published articles in the present Special Issue. Contributions have come from three continents and numerous countries (USA, Germany, France, Latvia, Poland, Russia, Japan, Korea and Thailand) indicating the global dimension of the subject.
KW - Leaching
KW - Recycling
KW - Nano-materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545099
DO - https://doi.org/10.3390/ma15062208
SN - 1996-1944
VL - 15
IS - 6
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-54509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charmi, Amir
A1 - Falkenberg, Rainer
A1 - Ávila, Luis
A1 - Mohr, Gunther
A1 - Sommer, Konstantin
A1 - Ulbricht, Alexander
A1 - Sprengel, Maximilian
A1 - Saliwan Neumann, Romeo
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Mechanical anisotropy of additively manufactured stainless steel 316L: An experimental and numerical study
N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations: 0◦, 45◦, and 90◦ relative to the build plate. Dynamic Young’s modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography (μCT), and texture analysis with electron backscatter diffraction (EBSD). These investigations revealed that the specimens exhibited near full density and the detected defects were spherical. Furthermore, the residual stresses in the loading direction were between −74 ± 24 MPa and 137 ± 20 MPa, and the EBSD measurements showed a preferential ⟨110⟩ orientation parallel to the build direction. A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture.
KW - Mechanical anisotropy
KW - Residual stress
KW - Crystal plasticity
KW - Selective laser melting (SLM)
KW - Laser beam melting (LBM)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511719
DO - https://doi.org/10.1016/j.msea.2020.140154
SN - 0921-5093
VL - 799
SP - 140154
PB - Elsevier B.V.
AN - OPUS4-51171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Ulbricht, Alexander
A1 - Heinrich, Ph.
A1 - Baum, D.
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - In-Situ Defect Detection in Laser Powder Bed Fusion by Using Thermography and Optical Tomography—Comparison to Computed Tomography
N2 - Among additive manufacturing (AM) technologies, the laser powder bed fusion (L-PBF) is one of the most important technologies to produce metallic components. The layer-wise build-up of components and the complex process conditions increase the probability of the occurrence of defects. However, due to the iterative nature of its manufacturing process and in contrast to conventional manufacturing technologies such as casting, L-PBF offers unique opportunities for in-situ monitoring. In this study, two cameras were successfully tested simultaneously as a machine manufacturer independent process monitoring setup: a high-frequency infrared camera and a camera for long time exposure, working in the visible and infrared spectrum and equipped with a near infrared filter. An AISI 316L stainless steel specimen with integrated artificial defects has been monitored during the build. The acquired camera data was compared to data obtained by computed tomography. A promising and easy to use examination method for data analysis was developed and correlations between measured signals and defects were identified. Moreover, sources of possible data misinterpretation were specified. Lastly, attempts for automatic data analysis by data Integration are presented.
KW - Laser powder bed fusion (L-PBF)
KW - Selective laser melting (SLM)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - Optical tomography
KW - Computed tomography (CT)
KW - Data fusion
KW - Lack-of-fusion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502417
DO - https://doi.org/10.3390/met10010103
VL - 10
IS - 1
SP - 103
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-50241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Fritsch, Tobias
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Bruno, Giovanni
A1 - Maierhofer, Christiane
A1 - Altenburg, Simon
T1 - On the Registration of Thermographic In Situ Monitoring Data and Computed Tomography Reference Data in the Scope of Defect Prediction in Laser Powder Bed Fusion
N2 - The detection of internal irregularities is crucial for quality assessment in metal-based additive manufacturing (AM) technologies such as laser powder bed fusion (L-PBF). The utilization of in-process thermography as an in situ monitoring tool in combination with post-process X-ray micro computed tomography (XCT) as a reference technique has shown great potential for this aim. Due to the small irregularity dimensions, a precise registration of the datasets is necessary as a
requirement for correlation. In this study, the registration of thermography and XCT reference datasets of a cylindric specimen containing keyhole pores is carried out for the development of a porosity prediction model. The considered datasets show variations in shape, data type and dimensionality, especially due to shrinkage and material elevation effects present in the manufactured part. Since the resulting deformations are challenging for registration, a novel preprocessing methodology is introduced that involves an adaptive volume adjustment algorithm which is based on the porosity distribution in the specimen. Thus, the implementation of a simple three-dimensional image-to-image registration is enabled. The results demonstrate the influence of the part deformation on the resulting porosity location and the importance of registration in terms of irregularity prediction.
KW - Selective laser melting (SLM)
KW - Laser powder bed fusion (L-PBF)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - X-ray computed tomography (XCT)
KW - Defect detection
KW - Image registration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549412
DO - https://doi.org/10.3390/met12060947
VL - 12
IS - 6
SP - 1
EP - 21
PB - MDPI
AN - OPUS4-54941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernádez-Canteli, A.
A1 - Castillo, E.
A1 - Blasón Gonzalez, Sergio
T1 - A methodology for phenomenological analysis of cumulative damage processes. Application to fatigue and fracture phenomena
N2 - Sample functions, i.e., stochastic process realizations, are used to define cumulative damage phenomena which end into an observable terminal state or failure. The complexity inherent to such phenomena justifies the use of phenomenological models associated with the evolution of a physical magnitude feasible to be monitored during the test. Sample functions representing the damage evolution may be identified, once normalized to the interval [0,1], with cumulative distribution functions (cdfs), generally, of the generalized extreme value (GEV) family. Though usually only a fraction of the whole damage evolution, according to the specific problem handled, is available from the test record, the phenomenological models proposed allow the whole damage process to be recovered. In this way, down- and upwards extrapolations of the whole damage process beyond the scope of the experimental program are provided as a fundamental tool for failure prediction in the practical design. The proposed methodology is detailed and its utility and generality confirmed by its successive application to representative well-known problems in fatigue and fracture characterization. The excellent fittings, the physical interpretation of the model parameters and the good expectations to achieve a complete probabilistic analysis of these phenomena justify the interest of the proposed phenomenological approach with possible applications to other cumulative damage processes.
KW - Bayesian technique
KW - Sample random results
KW - Stochastic sample functions
KW - Probabilistic assessment
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552371
DO - https://doi.org/10.1016/j.ijfatigue.2021.106311
SN - 0142-1123
VL - 150
SP - 106311
PB - Elsevier Ltd.
AN - OPUS4-55237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merz, Benjamin
A1 - Nilsson, R.
A1 - Garske, C.
A1 - Hilgenberg, Kai
T1 - Camera-based high precision position detection for hybrid additive manufacturing with laser powder bed fusion
N2 - Additive manufacturing (AM) in general and laser powder bed fusion (PBF-LB/M) in particular are becoming increasingly important in the field of production technologies. Especially the high achievable accuracies and the great freedom in design make PBF-LB/M interesting for the manufacturing and repair of gas turbine blades. Part repair involves building AM-geometries onto an existing component. To minimise the offset between component and AM-geometry, a precise knowledge of the position of the component in the PBF-LB/M machine is mandatory. However, components cannot be inserted into the PBF-LB/M machine with repeatable accuracy, so the actual position will differ for each part. For an offset-free build-up, the actual position of the component in the PBF-LB/M machine has to be determined. In this paper, a camera-based position detection system is developed considering PBF-LB/M constraints and system requirements. This includes finding an optimal camera position considering the spatial limitations of the PBF-LB/M machine and analysing the resulting process coordinate systems. In addition, a workflow is developed to align different coordinate systems and simultaneously correct the perspective distortion in the acquired camera images. Thus, position characteristics can be determined from images by image moments. For this purpose, different image segmentation algorithms are compared. The precision of the system developed is evaluated in tests with 2D objects. A precision of up to 30μm in translational direction and an angular precision of 0.021∘ is achieved. Finally, a 3D demonstrator was built using this proposed hybrid strategy. The offset between base component and AM-geometry is determined by 3D scanning and is 69μm.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Hybrid repair
KW - Machine vision
KW - Image processing
KW - Position detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568583
DO - https://doi.org/10.1007/s00170-022-10691-5
SP - 1
EP - 16
PB - Springer
AN - OPUS4-56858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudry, Mohsin Ali
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Experimental and numerical comparison of heat accumulation during laser powder bed fusion of 316L stainless steel
N2 - Heat accumulation during laser powder bed fusion (LPBF) of metallic build parts can adversely affect their microstructure and mechanical properties. To study the heat accumulation during 316L steel based parts manufactured by LPBF, a finite element method (FEM) based numerical study is carried out. For the investigation, a computationally efficient FEM based model, where the whole layer is simultaneously exposed to a heat source, is used. The simulation results are compared with experimental results to validate the numerical model. While considering different influencing factors such as volumetric energy density (VED) and inter-layer time (ILT), the FEM model is shown to successfully simulate the process of heat accumulation during LPBF based manufacturing of a cuboidal shaped geometry. It is shown that ILT and VED have a significant effect on heat accumulation. The validated numerical model provides a good basis for the optimization of processing parameters and geometries for a future investigation of a reduction of heat accumulation effects. Furthermore, it can be used to quickly provide preheating boundary conditions for detailed investigations by different model approaches at a finer scale for future studies.
KW - Laser powder bed fusion
KW - Finite element method
KW - Heat accumulation
KW - Inter-layer time
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545115
DO - https://doi.org/10.1007/s40964-022-00282-x
SP - 1
EP - 13
PB - Springer
AN - OPUS4-54511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderon, Luis Alexander
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - Elastic modulus data for additively and conventionally manufactured variants of Ti-6Al-4V, IN718 and AISI 316 L
N2 - This article reports temperature-dependent elastic properties (Young’s modulus, shear modulus) of three alloys measured by the dynamic resonance method. The alloys Ti-6Al-4V, Inconel IN718, and AISI 316 L were each investigated in a variant produced by an additive manufacturing processing route and by a conventional manufacturing processing route. The datasets include information on processing routes and parameters, heat treatments, grain size, specimen dimensions, and weight, as well as Young’s and shear modulus along with their measurement uncertainty. The process routes and methods are described in detail. The datasets were generated in an accredited testing lab, audited as BAM reference data, and are hosted in the open data repository Zenodo. Possible data usages include the verification of the correctness of the test setup via Young’s modulus comparison in low-cycle fatigue (LCF) or thermo-mechanical fatigue (TMF) testing campaigns, the design auf VHCF specimens and the use as input data for simulation purposes.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - AISI 316L
KW - IN 718
KW - Ti-6Al-4V
KW - Reference data
KW - Temperature dependence
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579716
DO - https://doi.org/10.1038/s41597-023-02387-6
VL - 10
IS - 1
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-57971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
T1 - New approach for multi-material design: Combination of laser beam and electromagnetic melt pool displacement by induced Lorentz forces
N2 - Multimaterial structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam, and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatially uncoupled from the influence of keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction and EDX analysis. The detected intermetallic phases consist of a 5–6 μm compact phase seam of Al5.6Fe2 and a needle-shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN.
KW - Electromagnetic forces
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Steel and aluminium
KW - Lorentz forces
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564840
DO - https://doi.org/10.2351/7.0000763
SN - 1042-346X
VL - 35
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-56484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brunner-Schwer, C.
A1 - Simón Muzás, Juan
A1 - Biegler, M.
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Laser Welding of L-PBF AM components out of Inconel 718
N2 - With regard to efficient production, it is desirable to combine the respective advantages of additively and conventionally manufactured components. Particularly in the case of large-volume components that also include filigree or complex structures, it makes sense to divide the overall part into individual elements, which afterwards have to be joined by welding.
The following research represents a first step in fundamentally investigating and characterizing the joint welding of Laser Powder Bed Fusion (L-PBF) components made of Inconel 718. For this purpose, bead-on-plate welds were performed on plates manufactured using the L-PBF process and compared with the conventionally manufactured material. Conventional laser beam welding was used as welding process. The weld geometry was investigated as a function of the L-PBF build-up orientation. It was found that the welding depth and weld geometry differ depending on this orientation and in comparison to the conventional material.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser Welding
KW - L-PBF
KW - PBF-LB/M
KW - Seam geometry
KW - Bead-on-plate welds
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560012
DO - https://doi.org/10.1016/j.procir.2022.08.072
SN - 2212-8271
VL - 111
SP - 92
EP - 96
PB - Elsevier B.V.
AN - OPUS4-56001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
A1 - Breese, Philipp Peter
A1 - Metz, C.
A1 - Hilgenberg, Kai
A1 - Maierhofer, Christiane
T1 - In-situ monitoring of the Laser Powder Bed Fusion build process via bi- chromatic optical tomography
N2 - As metal additive manufacturing (AM) is entering industrial serial production of safety relevant components, the need for reliable process qualification is growing continuously. Especially in strictly regulated industries, such as aviation, the use of AM is strongly dependent on ensuring consistent quality of components. Because of its numerous influencing factors, up to now, the metal AM process is not fully controllable. Today, expensive part qualification processes for each single component are common in industry.
This contribution focusses on bi-chromatic optical tomography as a new approach for AM in-situ quality control. In contrast to classical optical tomography, the emitted process radiation is monitored simultaneously with two temperature calibrated cameras at two separate wavelength bands. This approach allows one to estimate the local maximum temperatures during the manufacturing process, thus increases the comparability of monitoring data of different processes. A new process information level at low investment cost is reachable, compared to, e.g., infrared thermography.
T2 - LANE 2022
CY - Fürth, Germany
DA - 04.08.2022
KW - Optical tomography
KW - Additive Manufacturing
KW - L-PBF
KW - In-process monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560270
DO - https://doi.org/10.1016/j.procir.2022.08.035
SN - 2212-8271
VL - 111
SP - 340
EP - 344
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-56027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chubarenko, B.
A1 - Domnin, D.
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
A1 - Leitsin, V.
A1 - Tovpinets, A.
A1 - Karmanov, K.
A1 - Esiukova, E.
T1 - Change over Time in theMechanical Properties of Geosynthetics Used in Coastal Protection in the South-Eastern Baltic
N2 - The most massive design on the Baltic shore used geosynthetic materials, the landslide protection construction in Svetlogorsk (1300 m long, 90,000 m2 area, South-Eastern Baltic, Kaliningrad Oblast, Russian Federation) comprises the geotextile and the erosion control geomat coating the open-air cliff slopes. Due to changes in elastic properties during long-term use in the open air, as well as due to its huge size, this structure can become a non-negligible source of microplastic pollution in the Baltic Sea. Weather conditions affected the functioning of the structure, so it was assessed that geosynthetic materials used in this outdoor (open-air) operation in coastal protection structures degraded over time. Samples taken at points with different ambient conditions (groundwater outlet; arid places; exposure to the direct sun; grass cover; under landslide) were tested on crystallinity and strain at break. Tests showed a 39–85% loss of elasticity of the polymer filaments after 3 years of use under natural conditions. Specimens exposed to sunlight are less elastic and more prone to fail, but not as much as samples taken from shaded areas in the grass and under the landslide, which were the most brittle.
KW - Geosynthetics
KW - Microplastic
KW - Degradation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567978
UR - https://www.mdpi.com/2077-1312/11/1/113
DO - https://doi.org/10.3390/jmse11010113
SN - 2077-1312
VL - 11
IS - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-56797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gehrmann, H.-J.
A1 - Hiebel, M.
A1 - Simon, Franz-Georg
T1 - Methods for the Evaluation of Waste Treatment Processes
N2 - Decision makers for waste management are confronted with the problem of selecting the most economic, environmental, and socially acceptable waste treatment process. This paper elucidates evaluation methods for waste treatment processes for the comparison of ecological and economic aspects such as material flow analysis, statistical entropy analysis, energetic and exergetic assessment, cumulative energy demand, and life cycle assessment.The work is based on the VDI guideline 3925. A comparison of two thermal waste treatment plants with different process designs and energy recovery systems was performed with the described evaluation methods. The results are mainly influenced by the type of energy recovery, where the waste-to-energy plant providing district heat and process steam emerged to be beneficial in most aspects. Material recovery options from waste incineration were evaluated according to sustainability targets, such as saving of resources and environmental protection.
KW - Material flow analysis
KW - Life cycle assessment
KW - Cumulative energy demand
KW - Cost benefit analysis
KW - Eco-efficiency analysis
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-426455
UR - https://www.hindawi.com/journals/je/2017/3567865/
DO - https://doi.org/10.1155/2017/3567865
SN - 2314-4912
VL - 2017
SP - Article ID 3567865-1
EP - 13
PB - Hindawi
CY - London
AN - OPUS4-42645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abis, M.
A1 - Bruno, M.
A1 - Simon, Franz-Georg
A1 - Grönholm, R.
A1 - Hoppe, M.
A1 - Kuchta, K.
A1 - Fiore, S.
T1 - A Novel Dry Treatment for Municipal Solid Waste Incineration Bottom Ash for the Reduction of Salts and Potential Toxic Elements
N2 - The main obstacle to bottom ash (BA) being used as a recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. This work presents a dry treatment for the removal of salts and PTEs from BA particles. Two pilotscale abrasion units (with/without the removal of the fine particles) were fed with different BA samples. The performance of the abrasion tests was assessed through the analyses of particle size and moisture, and that of the column leaching tests at solid-to-liquid ratios between 0.3 and 4.
The results were: the particle-size distribution of the treated materials was homogeneous (25 wt % had dimensions <6.3 mm) and their moisture halved, as well as the electrical conductivity of the leachates. A significant decrease was observed in the leachates of the treated BA for sulphates (44%), chlorides (26%), and PTEs (53% Cr, 60% Cu and 8% Mo). The statistical analysis revealed good correlations between chloride and sulphate concentrations in the leachates with Ba, Cu, Mo, and Sr, illustrating the consistent behavior of the major and minor components of the layer surrounding BA particles. In conclusion, the tested process could be considered as promising for the improvement of BA valorization.
KW - Bottom ash
KW - Dry treatment
KW - Potential toxic elements
KW - Salts
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527963
DO - https://doi.org/10.3390/ma14113133
SN - 1996-1944
VL - 14
IS - 11
SP - 3133
PB - MDPI
CY - Basel
AN - OPUS4-52796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
T1 - Assessment of the Long-Term Leaching Behavior of Incineration Bottom Ash: A Study of Two Waste Incinerators in Germany
N2 - The long-term leaching behavior of incineration bottom ash (IBA) was studied with large-scale samples from two German waste incinerators with grate technology. The observation period was up to 281 days. The aging processes proceeded faster in the outdoor storage of the samples. The dominant factor in the leaching behavior is the pH, which starts at values above 12 and decreases to values below 10 (outdoors, <11 indoors). Most heavy metals exhibit minimum solubility in this pH range. The solubility of Sb depends on the prevailing Ca concentration, due to the formation of low-soluble Ca antimonate. The very low sulfate concentrations observed in the leaching tests with fresh IBA could be explained by the presence of ettringite. In the course of the aging reaction, ettringite is transformed into gypsum. The results from batch tests were compared with those from column tests, showing reasonable agreement. Leaching dynamics can be better followed with column tests. All results confirm that the use of IBA is possible under German law.
KW - Aging
KW - Incineration bottom ash
KW - Leaching
KW - Secondary building materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591599
DO - https://doi.org/10.3390/app132413228
SN - 2076-3417
VL - 13
IS - 24
SP - 1
EP - 15
PB - MDPI AG
CY - Basel
AN - OPUS4-59159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandow, N.
A1 - Aitken, M. D.
A1 - Geburtig, Anja
A1 - Kalbe, Ute
A1 - Piechotta, Christian
A1 - Schoknecht, Ute
A1 - Simon, Franz-Georg
A1 - Stephan, Ina
T1 - Using Environmental Simulations to Test the Release of Hazardous Substances from Polymer-Based Products: Are Realism and Pragmatism Mutually Exclusive Objectives?
N2 - The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented.
KW - Environmental simulations
KW - Polymer-based products
KW - Artificial weathering
KW - Degradation
KW - Leaching
KW - Soil contact
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509310
DO - https://doi.org/10.3390/ma13122709
SN - 1996-1944
VL - 13
IS - 12
SP - Paper 2709, 22
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pienkoß, Fabian
A1 - Abis, M.
A1 - Bruno, M.
A1 - Grönholm, R.
A1 - Hoppe, M.
A1 - Kuchta, K.
A1 - Fiore, S.
A1 - Simon, Franz-Georg
T1 - Heavy metal recovery from the fine fraction of solid waste incineration bottom ash by wet density separation
N2 - This work is aimed at exploring the recovery of heavy metals from the fine fraction of solid waste incineration bottom ash.
For this study, wet-discharged bottom ash fine-fraction samples from full-scale treatment plants in Germany and Sweden were analyzed. The potential for the recovery of heavy metal compounds was investigated through wet density-separation with a shaking table. The feed materials were processed without any pre-treatment and the optimum processing conditions were determined by means of design of experiments. Tilt angle and stroke frequency were identified as the most relevant parameters, and the optimum settings were − 7.5° and 266 rpm, respectively. The obtained balanced copper enrichments (and yields) were 4.4 (41%), 6.2 (28%) and 2.4 (23%). A maximum copper enrichment of 14.5 with 2% yield was achieved, providing a concentrate containing 35.9 wt.% relevant heavy metal elements. This included 26.3 wt.% iron, 4.3 wt.% zinc and 3.8 wt.% copper. In conclusion, density separation with shaking tables can recover heavy metals from bottom ash fine fractions. Medium levels of heavy metal enrichment (e.g., for Cu 2.7–4.4) and yield (Cu: 26–41%) can be reached simultaneously.
However, the separation performance also depends on the individual bottom ash sample.
KW - Bottom ash
KW - Density separation
KW - Circular economy
KW - Design of experiments
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538569
DO - https://doi.org/10.1007/s10163-021-01325-1
SN - 1438-4957
SN - 1611-8227
VL - 24
SP - 364
EP - 377
PB - Springer Nature
CY - Heidelberg
AN - OPUS4-53856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholz, Philipp
A1 - Putna-Nimane, I.
A1 - Barda, I.
A1 - Liepina-Leimane, I.
A1 - Strode, E.
A1 - Kileso, A.
A1 - Esiukova, E.
A1 - Chubarenko, B.
A1 - Purina, I.
A1 - Simon, Franz-Georg
T1 - Environmental impact of geosynthetics in coastal protection
N2 - Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed.
KW - Geosynthetics
KW - Geotextiles
KW - Dynamic surface leaching test
KW - Artificial ageing
KW - Marine littering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520576
DO - https://doi.org/10.3390/ma14030634
SN - 1996-1944
VL - 14
IS - 3 (Special issue: Measurement of the environmental impact of materials)
SP - 634-1
EP - 634-13
PB - MDPI
CY - Basel
AN - OPUS4-52057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Schinnen, Andrea
A1 - Riedel, Maren
A1 - Sommerfeld, Thomas
A1 - Sawal, G.
A1 - Bandow, N.
A1 - Vogel, Christian
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Investigation of pH-dependent extraction methods for PFAS in (fluoropolymer-based) consumer products: A comparative study between targeted and sum parameter analysis
N2 - Here, we report a comparative study of different sum parameter analysis methods for the extraction of per- and polyfluoroalkyl substances (PFAS) from manufactured consumer products, which can be measured by combustion ion chromatography (CIC). Therefore, a hydrolysis-based extraction method was further developed, which accounts for the addition of hydrolyzable covalently bound polyfluoroalkylated side-chain polymers (SFPs) to the extractable organic fluorine portion of the mass balance proposed as "hydrolyzable organically bound fluorine" (HOF). To test this hypothesis, the method was applied to 39 different consumer products containing fluoropolymers or monomeric PFAS taken from four different categories: outdoor textiles, paper packaging, carpeting, and permanent baking sheets. We also evaluated the method's efficiency by extracting four synthesized fluorotelomer polyacrylate reference compounds. The total fluorine (TF) and extractable organically bound fluorine (EOF) values were measured through CIC using established protocols. The TF values ranged from sub-ppb to %-levels, depending on the compound class. All samples showed results for hydrolyzed organofluorine (HOF) between 0.03 and 76.3 μg/g, while most EOF values were lower (100 mm). Furthermore, the evolution of the intrinsic preheating temperature during the build-up of specimens was monitored using a thermographic in-situ monitoring set-up. By applying recently determined emissivity values of 316L powder layers, real temperatures could be quantified. Heat accumulation led to preheating temperatures of up to about 600 °C. Significant differences in the preheating temperatures were discussed with respect to the individual process parameter combinations, including the build height. A strong effect of the inter layer time on the heat accumulation was observed. A shorter inter layer time resulted in an increase of the preheating temperature by more than a factor of 2 in the upper part of the specimens compared to longer inter layer times. This, in turn, resulted in heterogeneity of the microstructure and differences in material properties within individual specimens. The resulting differences in the microstructure were analyzed using electron back scatter diffraction and scanning electron microscopy. Results from chemical analysis as well as electron back scatter diffraction measurements indicated stable conditions in terms of chemical alloy composition and austenite phase content for the used set of parameter combinations. However, an increase of the average grain size by more than a factor of 2.5 could be revealed within individual specimens. Additionally, differences in feature size of the solidification cellular substructure were examined and a trend of increasing cell sizes was observed. This trend was attributed to differences in solidification rate and thermal gradients induced by differences in scanning velocity and preheating temperature. A change of the thermal history due to intrinsic preheating could be identified as the main cause of this heterogeneity. It was induced by critical combinations of the energy input and differences in heat transfer conditions by variations of the inter layer time. The microstructural variations were directly correlated to differences in hardness.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - In-situ process monitoring
KW - Thermography
KW - Heat accumulation
KW - Inter layer time
KW - Cellular substructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529240
DO - https://doi.org/10.3390/met11071063
VL - 11
IS - 7
SP - 1063
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-52924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Breese, Philipp Peter
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Altenburg, Simon
T1 - A deep learning framework for defect prediction based on thermographic in-situmonitoring in laser powder bed fusion
N2 - The prediction of porosity is a crucial task for metal based additive manufacturing techniques such as laser powder bed fusion. Short wave infrared thermography as an in-situ monitoring tool enables the measurement of the surface radiosity during the laser exposure. Based on the thermogram data, the thermal history of the component can be reconstructed which is closely related to the resulting mechanical properties and to the formation of porosity in the part. In this study, we present a novel framework for the local prediction of porosity based on extracted features from thermogram data. The framework consists of a data pre-processing workflow and a supervised deep learning classifier architecture. The data pre-processing
workflow generates samples from thermogram feature data by including feature information from multiple subsequent layers.
Thereby, the prediction of the occurrence of complex process phenomena such as keyhole pores is enabled. A custom convolutional neural network model is used for classification. Themodel is trained and tested on a dataset from thermographic in-situ monitoring of the manufacturing of an AISI 316L stainless steel test component. The impact of the pre-processing parameters and the local void distribution on the classification performance is studied in detail. The presented model achieves an accuracy of 0.96 and an f1-Score of 0.86 for predicting keyhole porosity in small sub-volumes with a dimension of (700 × 700 × 50) μm3. Furthermore, we show that pre-processing parameters such as the porosity threshold for sample
labeling and the number of included subsequent layers are influential for the model performance. Moreover, the model prediction is shown to be sensitive to local porosity changes although it is trained on binary labeled data that disregards the actual sample porosity.
KW - Laser Powder Bed Fusion (PBF-LB/M, L-PBF)
KW - Selective Laser Melting (SLM)
KW - SWIR thermography
KW - Online monitoring
KW - Flaw detection
KW - Machine learning
KW - Convolutional neural networks (CNN)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575148
DO - https://doi.org/10.1007/s10845-023-02117-0
SN - 0956-5515
SP - 1
EP - 20
PB - Springer
AN - OPUS4-57514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -