TY - CONF A1 - Niederleithinger, Ernst A1 - Kruschwitz, Sabine A1 - Behrens, Matthias T1 - Spectral induced polarization (SIP) measurements for stability assessment of tailings dams T2 - 18th Annual Meeting SAGEEP, Symposium on the Application of Geophysics to Engineering and Environmental Problems, "Geophysical Solutions for Today´s Challenges" CY - Atlanta, GA, USA DA - 2005-04-03 KW - Geophysik KW - Geotechnik KW - Halden KW - Umwelt KW - Bergbau PY - 2005 SP - 298 EP - 305 PB - Environmental and Engineering Geophysical Society CY - Atlanta AN - OPUS4-11469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Wöstmann, Jens A1 - Behrens, Matthias A1 - Wiggenhauser, Herbert T1 - Automated NDE of post-tensioned concrete bridges using imaging echo methods T2 - International Conference on Bridges, "Bridges" CY - Dubrovnik, Croatia DA - 2006-05-21 KW - Automated NDE KW - Imaging echo methods KW - Radar KW - Impact-echo KW - Ultrasonic echo KW - PT concrete bridges PY - 2006 SN - 3-931381-86-2 SP - 985 EP - 992 PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Wöstmann, Jens A1 - Behrens, Matthias A1 - Wiggenhauser, Herbert T1 - Automated NDE of post-tensioned concrete bridges using radar, ultrasonic echo and impact-echo T2 - NDE Conference on Civil Engineering CY - St. Louis, Missouri, USA DA - 2006-08-14 KW - Automatisierte ZfPBau-Verfahren KW - Radar KW - Ultraschallecho KW - Impact-Echo KW - Spannbetonbrücken PY - 2006 SN - 1-57117-148-7 SP - 439 EP - 444 PB - ASTM CY - St. Louis AN - OPUS4-13942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Wöstmann, Jens A1 - Behrens, Matthias A1 - Wiggenhauser, Herbert T1 - Automated NDE of post-tensioned concrete bridges using imaging echo methods T2 - 29. Darmstädter Massivbauseminar, "Sicherheitsgewinn durch Monitoring?" CY - Darmstadt, Germany DA - 2006-09-14 KW - Zerstörungsfreie Prüfung im Bauwesen KW - Brückenuntersuchungen PY - 2006 SP - 477 EP - 487 PB - Freunde des Instituts für Massivbau der Technischen Universität Darmstadt CY - Darmstadt AN - OPUS4-14397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Wöstmann, Jens A1 - Behrens, Matthias ED - Russel, M. ED - Basheer, P. T1 - Automated application and combination of non-destructive echo methods for the investigation of post-tensioned concrete bridges T2 - Concrete Platform CY - Belfast, Großbritannien, Northern Ireland DA - 2005-04-19 KW - Automated testing KW - Data fusion KW - Impact-echo KW - Post-tensioned concrete bridges KW - Radar KW - Ultrasonic echo PY - 2007 SN - 978-0-85389-913-6 SP - 261 EP - 269 PB - Queen's University of Belfast CY - Belfast AN - OPUS4-14792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prabhakara, Prathik A1 - Mielentz, Frank A1 - Stolpe, Heiko A1 - Behrens, Matthias A1 - Lay, Vera A1 - Niederleithinger, Ernst T1 - Ultrasonic Investigation for the Quality Assurance of Sealing Structures in Radioactive Waste Repositories N2 - The structural integrity of sealing structures in underground repositories for radioactive waste is a major concern regarding safe disposal. Non-destructive testing plays a very important role in the safety of this sealing structures. Ultrasonic pulse echo technology has been established in the construction industry as a non-destructive testing method for locating potential defects and material characterization of concrete structures. A borehole probe is an ultrasonic pulse-echo device used to investigate the internal structures of salt concrete. A prototype borehole probe is successfully demonstrated with the existing research borehole in the test site using a commercially available flaw detector. A novel phased array borehole probe that allows the beam to be focused based on the delay law was constructed and tested. The directivity measurements on the semi-cylindrical concrete sample agree well with the simulation results for the different focusing angles. In combination with geophysical reconstruction methods, the optimized radiation pattern of the probe is expected to improve the signal quality and thus increase the reliability of the imaging results. In addition, a unique large aperture ultrasound system (LAUS) is expected to provide enhanced images of possible cracks and embedded objects in in-situ structures. LAUS will be optimized to reliably detect objects at depths greater than 9 m and, at the same time, provide good resolution. Modeling studies show the potential to increase the distance between the transducer arrays further, and the same configuration has been successfully tested on a thick concrete wall. Overall, the paper shows that quality assurance using ultrasonic testing is crucial for constructing safe sealing structures to dispose of radioactive or toxic waste. T2 - NDE 2022 CY - Gandhinagar, India DA - 24.12.2022 KW - Ultrasonic Testing KW - Engineered barrier KW - Phased array technique KW - Non-destructive testing civil engineering KW - Quality assurance PY - 2022 AN - OPUS4-56802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielentz, Frank A1 - Stolpe, Heiko A1 - Effner, Ute A1 - Behrens, Matthias A1 - Bernstein, Thomas A1 - Niederleithinger, Ernst T1 - Entwicklung einer Bohrlochsonde für Ultraschalluntersuchungen an Abschlussbauwerken in Endlagern N2 - Für die Qualitätssicherung von Abschlusswerken für Endlager wird eine Ultraschall-Bohrlochsonde entwickelt. Mithilfe dieser Sonde, die aus einer Vielzahl von einzelnen koppelmittelfreien Ultraschall-Punktkontaktprüfköpfen besteht, soll die Rissfreiheit der Versuchsbauwerke überprüft werden. Ein erster Prototyp der Sonde wurde mit einem kommerziellen Ultraschallgerät betrieben und bestand aus 12 Transversalwellen-Punktkontaktprüfköpfen von denen jeweils sechs als Sender und sechs als Empfänger parallelgeschaltet waren. Um den erzeugten Schalldruck der Bohrlochsonde zu steigern, wurde bei der Neuentwicklung die Prüfkopfanzahl erhöht und zusätzlich die laufzeitgesteuerte Anregung der einzelnen Prüfköpfe vorgesehen. Für die Anregung der Prüfköpfe mit programmierten Zeitverzögerungen wurde ein neuartiger mehrkanaliger Sender für bipolare Rechtecksignale entwickelt. Durch die Entwicklung der Bohrlochsonde soll eine dynamische Anpassung der Prüfkopf-Apertur sowie eine Fokussierung des Schallfeldes in Abhängigkeit der zu untersuchenden Tiefe erfolgen. Mithilfe entsprechender Anregungsfunktionen kann das Schallfeld der Bohrlochsonde unterschiedlich geformt werden, z. B. ist auch ein Schwenken des fokussierten Schallbündels möglich. Dadurch wird das erfasste Prüfvolumen begrenzt und auf diese Weise das Signal-Störverhältnis der Empfangssignale verbessert. In Kombination mit SAFT-Rekonstruktionsrechnungen wird durch eine optimierte Abstrahlcharakteristik der Sonde mit einem hohen Schalldruck unter verschiedenen Winkeln eine verbesserte Signalqualität und damit eine erhöhte Aussagesicherheit der Ergebnisse in der Objektabbildung erwartet. T2 - DGZfP-Jahrestagung 2021 CY - Online meeting DA - 10.05.2021 KW - Abdichtbauwerk KW - Bohrlochsonde KW - Ultraschall-Echoverfahren KW - Verschlussbauwerk KW - Zerstörungsfreie Prüfung KW - Ultraschall-Messtechnik PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526746 UR - https://jahrestagung.dgzfp.de/portals/jt2021/bb176/inhalt/poster.htm SN - 978-3-947971-18-3 VL - 176 SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-52674 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prabhakara, Prathik A1 - Lay, Vera A1 - Mielentz, Frank A1 - Niederleithinger, Ernst A1 - Behrens, Matthias T1 - Enhancing the Performance of a Large Aperture Ultrasound System (LAUS): A Combined Approach of Simulation and Measurement for Transmitter–Receiver Optimization N2 - The Large Aperture Ultrasound System (LAUS) developed at BAM is known for its ability to penetrate thick objects, especially concrete structures commonly used in nuclear waste storage and other applications in civil engineering. Although the current system effectively penetrates up to ~9 m, further optimization is imperative to enhance the safety and integrity of disposal structures for radioactive or toxic waste. This study focuses on enhancing the system’s efficiency by optimizing the transducer spacing, ensuring that resolution is not compromised. An array of twelve horizontal shear wave transducers was used to find a balance between penetration depth and resolution. Systematic adjustments of the spacing between transmitter and receiver units were undertaken based on target depth ranges of known reflectors at depth ranges from 5 m to 10 m. The trade-offs between resolution and artifact generation were meticulously assessed. This comprehensive study employs a dual approach using both simulations and measurements to investigate the performance of transducer units spaced at 10 cm, 20 cm, 30 cm, and 40 cm. We found that for depths up to 5 m, a spacing of 10 cm for LAUS transducer units provided the best resolution as confirmed by both simulations and measurements. This optimal distance is particularly effective in achieving clear reflections and a satisfactory signal-to-noise ratio (SNR) in imaging scenarios with materials such as thick concrete structures. However, when targeting depths greater than 10 m, we recommend increasing the distance between the transducers to 20 cm. This increased spacing improves the SNR in comparison to other spacings, as seen in the simulation of a 10 m deep backwall. Our results emphasize the critical role of transducer spacing in achieving the desired SNR and resolution, especially in the context of depth imaging requirements for LAUS applications. In addition to the transducer spacing, different distances between individual sets of measurement positions were tested. Overall, keeping the minimal possible distance between measurement position offsets provides the best imaging results at greater depths. The proposed optimizations for the LAUS in this study are primarily relevant to applications on massive nuclear structures for nuclear waste management. This research highlights the need for better LAUS efficiency in applications such as sealing structures, laying the foundation for future technological advances in this field. KW - Engineered barrier system KW - Phased array technique KW - Ultrasonic testing KW - Non-destructive testing in civil engineering KW - Seismic migration PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592426 DO - https://doi.org/10.3390/s24010100 VL - 24 IS - 1 SP - 1 EP - 23 PB - MDPI CY - Basel, Switzerland AN - OPUS4-59242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prabhakara, Prathik A1 - Mielentz, Frank A1 - Stolpe, Heiko A1 - Behrens, Matthias A1 - Lay, Vera A1 - Niederleithinger, Ernst T1 - Validation of novel ultrasonic phased array borehole probe by using simulation and measurement N2 - Low-frequency ultrasonic testing is a well-established non-destructive testing (NDT) method in civil engineering for material characterization and the localization of cracks, reinforcing bars and delamination. A novel ultrasonic borehole probe is developed for in situ quality assurance of sealing structures in radioactive waste repositories using existing research boreholes. The aim is to examine the sealing structures made of salt concrete for any possible cracks and delamination and to localize built-in components. A prototype has been developed using 12 individual horizontal dry point contact (DPC) shear wave transducers separated by equidistant transmitter/receiver arrays. The probe is equipped with a commercially available portable ultrasonic flaw detector used in the NDT civil engineering industry. To increase the sound pressure generated, the number of transducers in the novel probe is increased to 32 transducers. In addition, the timed excitation of each transducer directs a focused beam of sound to a specific angle and distance based on the previously calculated delay time. This narrows the sensitivity of test volume and improves the signal-to-noise ratio of the received signals. In this paper, the newly designed phased array borehole probe is validated by beam computation in the CIVA software and experimental investigations on a half-cylindrical test specimen to investigate the directional characteristics. In combination with geophysical reconstruction methods, it is expected that an optimised radiation pattern of the probe will improve the signal quality and thus increase the reliability of the imaging results. This is an important consideration for the construction of safe sealing structures for the safe disposal of radioactive or toxic waste. KW - Ultrasound KW - Phased array KW - Concrete KW - Borehole PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565722 DO - https://doi.org/10.3390/s22249823 SN - 1424-8220 VL - 22 IS - 24 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-56572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prabhakara, Prathik A1 - Mielentz, Frank A1 - Stolpe, Heiko A1 - Behrens, Matthias A1 - Lay, Vera A1 - Niederleithinger, Ernst T1 - Construction and validation of a novel phased array borehole probe for ultrasonic investigations at sealing structures in radioactive repositories N2 - A new type of ultrasonic borehole probe is currently under development for the quality assurance of sealing structures in radioactive waste repositories using existing research boreholes. The goal is to examine the sealing structures made of salt concrete for possible cracks, delamination, and embedded objects. Earlier prototype probes use 12 or 16 individual dry point contact (DPC) horizontal shear wave transducers grouped into a transmitter and a receiver array, each made up of six or eight individual transducers. They are operated with a commercially available portable ultrasonic flaw detector used in the civil engineering industry. To increase the generated sound pressure of the borehole probe, the number of transducers in the novel probe is increased to 32. In addition, timed excitation of each probe is used to direct a focused sound beam to a specific angle and distance based on calculated time delays. Hence, the sensitive test volume is limited, and the signal-to-noise ratio of the received signals is improved. This paper presents the validation of the newly developed phased array borehole probe by beam computation in CIVA software and experimental investigations on a semi-cylindrical test specimen to investigate the directional characteristics. In combination with geophysical reconstruction techniques, an optimised radiation pattern of the probe is expected to improve the signal quality and thus increase the reliability of the imaging results. This is of great importance for the construction of safe sealing structures needed for the disposal of radioactive or toxic waste. T2 - NDT-CE 2022 CY - Zurich, Switzerland DA - 16.08.2022 KW - Borehole probe KW - Phased array technique KW - SealWasteSafe KW - Monitoring KW - Engineered barrier; PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568016 SN - 1435-4934 SP - 1 EP - 4 PB - NDT.net AN - OPUS4-56801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Krause, Martin A1 - Borchardt, Kerstin A1 - Lange, Marco A1 - Behrens, Matthias A1 - Maack, Stefan A1 - Mielentz, Frank A1 - Milmann, Boris A1 - Schaurich, Dieter A1 - Wöstmann, Jens A1 - Hintzpeter, F. A1 - Sodeikat, C. T1 - Kosteneinsparung durch Anwendung zerstörungsfreier Prüfverfahren für Betonbauteile beim Bauen im Bestand N2 - In Zeiten knapper Kassen wird überall nach Wegen gesucht Kosten einzusparen. Im Bauwesen geht es dabei um Kosteneinsparungen ohne Reduktion der Sicherheit und Dauerhaftigkeit des Bauwerks. Beim Bauen im Bestand können mit einer zerstörungsfreien Prüfung von Bauwerken die Weiternutzung oder die erforderlichen Umbauten optimiert werden und so Kosten eingespart werden. KW - Zerstörungsfreie Prüfung KW - Bauen im Bestand KW - Radar KW - Ultraschallecho KW - Kosteneinsparung PY - 2011 SN - 978-3-8167-8611-5 VL - 101 SP - 1 EP - 95 PB - Fraunhofer IRB Verl. CY - Stuttgart ET - Abschlussbericht AN - OPUS4-26649 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grohmann, Maria A1 - Maack, Stefan A1 - Behrens, Matthias A1 - Niederleithinger, Ernst T1 - Low-frequency ultrasonic pulse-echo datasets for geometry determination of a reinforced concrete step specimen with embedded polystyrene foam cuboids in non-destructive testing N2 - The dataset comprises raw data collected using the ultrasonic pulse-echo method on a concrete specimen. The specimen addresses two fundamental non-destructive testing (NDT) challenges in civil engineering: locating built-in elements and determining dimensions to analyse both the internal and external geometry of concrete structures. For data acquisition, the surface of the concrete specimen was automatically scanned point by point, with pulse-echo measurements performed at each measuring point. The automation of the measurement process ensured high repeatability and precision as well as a high measurement point density. Two low-frequency probes were used, each capable of both transmitting and receiving ultrasonic waves: one for longitudinal waves and one for shear waves. The longitudinal wave probe operates at frequencies of up to approximately 160 kHz, whereby a frequency of 80 kHz was used for the ultrasonic measurements here. The shear wave probe operates at up to 100 kHz, with a frequency of 50 kHz used for the measurements in this study. This article includes additional technical specifications of the two ultrasonic probes used, as well as information on their geometric specifications and directivity patterns. It also provides a detailed description of the further measurement equipment used. The ultrasonic raw data are stored in a universally readable format, with each time signal (A-scan) spanning two milliseconds and a sampling rate of two mega-samples per second. The provided data support comparative studies in signal analysis, imaging as well as interpretation and can be used for evaluation purposes in various practical NDT scenarios. KW - Civil engineering KW - Concrete structures KW - Ultrasonic echo testing KW - Reference data PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639100 DO - https://doi.org/10.1016/j.dib.2025.111956 SN - 2352-3409 VL - 62 SP - 1 EP - 19 PB - Elsevier Inc. AN - OPUS4-63910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst A1 - Kruschwitz, Sabine A1 - Behrens, Matthias A1 - Brink, Arne T1 - Multichannel Spectral Induced Polarization (SIP) - Application to Geotechnics and Construction Materials T2 - 10th European Meeting of Environmental and Engineering Geophysics (Near Surface 2004) CY - Utrecht, Niederlande DA - 2004-09-06 KW - SIP KW - Geotechnik KW - Geoelektrik KW - Baustoffe KW - Feuchtigkeit KW - Porosität KW - Spülhalden PY - 2004 SP - 4 pages PB - EAEG CY - Houten AN - OPUS4-4053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Niederleithinger, Ernst A1 - Taffe, Alexander A1 - Behrens, Matthias ED - Stahlmann, J. T1 - RUFUS - Re-Use of Foundations on Urban Sites - Ein EU-Projekt zur Wiedernutzung von Fundamenten T2 - 7. Pfahl-Symposium CY - Braunschweig, Deutschland DA - 2003-02-20 PY - 2003 SN - 3-927610-62-3 N1 - Serientitel: Mitteilung des Instituts für Grundbau und Bodenmechanik - Technische Universität Braunschweig – Series title: Mitteilung des Instituts für Grundbau und Bodenmechanik - Technische Universität Braunschweig IS - 71 SP - 1(?) EP - 2(?) CY - Braunschweig AN - OPUS4-2761 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kruschwitz, Sabine A1 - Niederleithinger, Ernst A1 - Behrens, Matthias A1 - Mittag, Kornelia T1 - Zerstörungsfreie Strukturuntersuchung von Spülhaldendämmen mittles SIP T2 - Jahrestagung Deutsche Geophysikalische Gesellschaft (DGG) CY - Graz, Österreich DA - 2005-02-21 KW - Spektrale Induzierte Polarisation KW - Spülhalden KW - Dammstabilität PY - 2005 SN - 0344-7251 SP - 113 EP - 114 PB - DGG CY - wechselnde Verlagsorte AN - OPUS4-7214 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Niederleithinger, Ernst A1 - Taffe, Alexander A1 - Behrens, Matthias T1 - Pfahlprüfung - Grenzbereich zwischen Bauingenieurwesen und Geophysik T2 - Jahrestagung Deutsche Geophysikalische Gesellschaft (DGG) CY - Graz, Österreich DA - 2005-02-21 KW - Fundamente KW - Bohrpfähle KW - Pfahlprüfung KW - Pfahlintegritätsprüfung KW - Parallel Seismic Verfahren KW - Geophysik PY - 2005 SN - 0344-7251 SP - 287 PB - DGG CY - wechselnde Verlagsorte AN - OPUS4-7239 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Behrens, Matthias A1 - Kohl, Christoph A1 - Wöstmann, Jens A1 - Wiggenhauser, Herbert A1 - Petz, J. T1 - Großflächige ZfPBau-Untersuchungen an Hohlkastenbrücken der A 23 - Südosttangente Wien N2 - Mit Radar, Impact-Echo und Ultraschallecho wurden 2004/2005 zwei Spannbetonbrücken der stark befahrenen A 23 Südosttangente in Wien zerstörungsfrei untersucht. Bei den Bauwerken handelt es sich um Hohlkastenbrücken, die 1975/76 unter Verwendung unterschiedlicher Spannsysteme errichtet wurden. Durch Messungen mit den zerstörungsfreien Prüfverfahren an den Außenseiten zweier Hohlkastenstege wurde sowohl die schlaffe Bewehrung als auch Längsspannglieder in den Stegen geortet. Darüber hinaus sollte der Verpresszustand der Spannglieder mit Hilfe der akustischen Verfahren Impact-Echo und Ultraschallecho ermittelt werden. T3 - BAM Forschungsberichtreihe - 278 PY - 2006 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-1735 SN - 978-3-86509-529-1 SN - 0938-5533 VL - 278 SP - 1 EP - 46 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-173 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Streicher, Doreen A1 - Algernon, Daniel A1 - Behrens, Matthias A1 - Wöstmann, Jens A1 - Wiggenhauser, Herbert A1 - Petz, J. T1 - Zerstörungsfreie Zustandsuntersuchungen an Spannbetonbrücken unter Verkehr T2 - DGZfP-Fachtagung Bauwerksdiagnose "Praktische Anwendungen Zerstörungsfreier Prüfungen" CY - Berlin, Deutschland DA - 2006-02-22 KW - Automatisierte ZfPBau-Verfahren KW - Radar KW - Ultraschallecho KW - Impact-Echo KW - Spannbetonbrücken PY - 2006 SN - 3-931381-71-4 SP - 237 EP - 244 PB - DGZfP CY - Berlin AN - OPUS4-12159 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -