TY - CONF A1 - Niederleithinger, Ernst A1 - Wiggenhauser, Herbert T1 - The LAUS: First Applications of a New System for Ultrasonic Imaging of Very Concrete Structures N2 - The LAUS (Large Aperture Ultrasonic System) has been developed to image very thick concrete structures, which are not accessible for commercial systems. The device and the corresponding software is the result of joint Research of BAM, an ultrasonic instrument manufacturer and University of Kassel, Germany. It consists of 12 separate Arrays of 32 point-contact shear wave transducers each, which can be deployed in flexible configurations. Each array is combined with battery and transmitter, receiver and wireless communication electronics. Three case histories are presented. First the system was deployed on a 5-m thick heavily reinforced foundation slab. The reflection of the slab’s bottom was imaged clearly. In addition, a multiple reflection was registered, thus giving hope that even thicker elements might be imaged by the instrument. Second, the LAUS was used to investigate a massive bridge girder where a heavy rainstorm during concreting had led to imperfections that were visible after removing the formwork was removed. The LAUS could image tendon ducts in 1.8m depth and the backwall closely behind them. Some limited areas showed blurred reflections and were checked by drill holes; these areas were affected by diffuse damage which could be repaired by injections. Third, a large retaining wall was checked for thickness. Meanwhile, the LAUS has been used in underground waste deposits (nuclear and other) for quality assurance of sealing plugs. A confirmed penetration depth of about 7 m has been reached. T2 - SMT and NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.08.2018 KW - LAUS (Large Apertur Ultrasonic System) KW - Ultrasonic echo KW - Deep penetration KW - Concrete PY - 2019 UR - https://asnt.org/smt18papers SN - 978-1-57117-456-7 VL - 11/19 SP - 208 EP - 213 PB - The American Society for Nondestructive Testing, Inc. CY - Columbus, OH, USA AN - OPUS4-47238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Oesch, Tyler A1 - Stelzner, Ludwig A1 - Weise, Frank ED - Herrmann, H. ED - Schnell, J. T1 - Non-destructive evaluation of the contribution of polymer-fibre orientation and distribution characteristics to concrete performance during fire N2 - Although concrete itself is not a combustible material, concrete mixtures with high density, such has high-performance concretes (HPCs), are susceptible to significant damage during fires due to explosive spalling. Past research has shown that the inclusion of polymer fibres in high density concrete can significantly mitigate this fire damage. The exact mechanisms causing this increased spalling resistance are not yet fully under-stood, but it is thought that the fibres facilitate moisture transport during fire exposure, which in turn contributes to relief of internal stresses in the spalling-susceptible region. In this study, X-ray Computed Tomography (CT) was applied to observe the interaction between polymer fibres and cracking during thermal exposure. For this purpose, two concrete samples containing different polymer fibre types were subjected to incremental application of a defined thermal exposure. CT images were acquired before and after each thermal exposure and powerful image processing tools were used to segment the various material components. This enabled a detailed analysis of crack formation and propagation as well as the visualization and quantification of polymer fibre characteristics within the concrete. The results demonstrated that the orientation of both fibres and cracks in polymer-fibre reinforced concrete tend to be anisotropic. The results also indicated that crack geometry characteristics may be correlated with fibre orientation, with cracks tending to run parallel to fibre beds. Clear quantitative relationships were also observed between heating and increasing cracking levels, expressed in terms of both crack surface area and crack volume. KW - X-ray Computed Tomography (CT) KW - Polypropylene Fibres KW - Fire Performance KW - Fibre-Reinforced Concrete (FRC) KW - Fibre Orientation Analysis PY - 2019 SN - 978-3-030-00868-0 DO - https://doi.org/10.1007/978-3-030-00868-0 SP - 51 EP - 73 PB - Springer Nature Switzerland AG AN - OPUS4-47206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thiel, Erik A1 - Ziegler, Mathias A1 - Studemund, Taarna T1 - Localization of subsurface defects in uncoated aluminum with structured heating using high-power VCSEL laser arrays N2 - We report on photothermal detection of subsurface defects by coherent superposition of thermal wave fields. This is made possible by structured heating using high-power VCSEL laser arrays whose individual emitter groups can be arbitrarily controlled. In order to locate the defects, we have developed a scanning method based on the continuous wavelet transformation with complex Morlet wavelet using the destructive interference effect of thermal waves. This approach can also be used for thermally very fast and highly reflective materials such as uncoated aluminum. We show that subsurface defects at an aspect ratio of defect width to defect depth down to 1/3 are still detectable in this material. KW - Thermography KW - Heat diffusion KW - Laser thermography KW - Structured heating KW - NDT KW - Subsurface defects KW - Thermal wave KW - VCSEL KW - Wavelet transformation PY - 2019 DO - https://doi.org/10.1007/s10765-018-2478-9 SN - 1572-9567 SN - 0195-928X VL - 40 IS - 2 SP - 17, 1 EP - 13 PB - Springer Science+Business Media, LLC, part of Springer Nature 2019 AN - OPUS4-47208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Kotschate, Daniel A1 - Bartusch, Jürgen A1 - Hansen, L. A1 - Kersten, H. T1 - Neue Entwicklungen im Bereich der luftgekoppelten Ultraschallprüfung N2 - Es wird über Ferroelektret-Wandler, thermoakustische Wandler und Plasma-Wandler für luftgekoppelte Ultraschallprüfung berichtet. T2 - Sitzung des Arbeitskreises Berlin der DGZfP CY - Berlin, Germany DA - 12.02.2019 KW - Luftultraschall KW - Ferroelektret KW - Thermoakustik KW - Plasma PY - 2019 AN - OPUS4-47375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Heckel, Thomas T1 - Ultraschallprüfung in der BAM (Fachbereich 8.4 - Zerstörungsfreie Prüfung - Akustische und elektromagnetische Verfahren) N2 - Vorstellung des Fachbereichs 8.4 mit dem Schwerpunkt Ultraschallprüfung. T2 - Sitzung des DFG-Schwerpunktprogramms Zyklische Schädigungsprozesse in Hochleistungsbetonen im Experimental-Virtual-Lab2020 CY - Berlin, Germany DA - 6.2.2019 KW - Luftultraschall KW - Ultraschall KW - Phased Array KW - Simulation KW - Wirbelstrom KW - Magnetfeldsensoren PY - 2019 AN - OPUS4-47376 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bellon, Carsten A1 - Burger, Karin A1 - Gollwitzer, Christian T1 - Virtual CT acquisition and reconstruction of complex and noisy scanning trajectories in aRTist N2 - In modern CT imaging, simulation has become an important tool to minimize cost- and time-intensive measurements. It is increasingly used to optimize techniques for complex applications, to support the preparation of written procedures, and for educational purposes. We extended the CT simulation software ‘aRTist’ with a module to set-up arbitrary trajectories including disturbing influences during the scan. Moreover, such geometric deviations can be compensated by the internal reconstruction tool. T2 - 9th Conference on Industrial Computed Tomography (iCT) CY - Padua, Italy DA - 13.02.2019 KW - Simulation KW - Arbitrary trajectories KW - Projection matrix KW - Filtered back projection PY - 2019 AN - OPUS4-47476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Yogita A1 - Weidner, Steffen T1 - Synchrotron based absorption edge tomography for the analysis of 3D printed polymer MOF N2 - Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF. T2 - iCT 2019 CY - Padua, Italy DA - 12.02.2019 KW - Synchrotron tomography KW - BAMline KW - MOF KW - Absorption edge tomography PY - 2019 AN - OPUS4-47391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Yogita A1 - Weidner, Steffen T1 - Synchrotron based absorption edge tomography for the analysis of 3D printed polymer MOF N2 - Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF. T2 - iCT 2019 CY - Padua, Italy DA - 12.02.2019 KW - Synchrotron tomography KW - BAMline KW - MOF KW - Absorption edge tomography PY - 2019 AN - OPUS4-47392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Evsevleev, Sergei A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Kupsch, Andreas T1 - Refraction driven X-ray caustics at curved interfaces N2 - X-ray refraction related interaction has received rising interest since about two decades in the field of imaging, beam shaping and analysis although being discovered a century ago. Due to refraction at interfaces in inhomogeneous media X-rays undergo natural focusing (or defocusing) of waves, revealing caustics. Such Kind of intensity patterns are well-known for visible light, but have been sparsely discussed for X-rays. The Variation of irradiation density may be predicted in case of known shapes. Analogously to light optics, the intensity distributions cover several orders of magnitude including complete extinction. The partly convergent (and divergent) caustic stripes originate from narrow zones of typical size of some 10−6 of the boundary curvature radius. For the deflection of plane wave synchrotron radiation (energy in the range of some keV to some ten keV) at rods and tubes of several μm diameter, we find good Agreement between experiments and modeling by ray tracing according to Snell’s law without additional diffraction contributions. Apart from Basic Research implications, caustics may influence the performance of irradiation technologies such as sterilization or molecular cross-linking. KW - X-ray caustics KW - X-ray refraction KW - Irradiation KW - Radiation shielding KW - Synchrotron Radiation PY - 2019 UR - http://www.sciencedirect.com/science/article/pii/S0168900218314591 DO - https://doi.org/10.1016/j.nima.2018.10.152 SN - 0168-9002 SN - 1872-9576 VL - 916 SP - 275 EP - 282 PB - Elsevier AN - OPUS4-46924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Delbeck, S. A1 - Vahlsing, Thorsten A1 - Leonhardt, S. A1 - Steiner, G. A1 - Heise, H.M. T1 - Non-invasive monitoring of blood glucose using optical methods for skin spectroscopy - opportunities and recent advances N2 - Diabetes mellitus is a widespread disease with greatly rising patient numbers expected in the future, not only for industrialized countries but also for regions in the developing world. There is a need for efficient therapy, which can be via self-monitoring of blood glucose levels to provide tight glycemic control for reducing the risks of severe health complications. Advancements in diabetes technology can nowadays offer different sensor approaches, even for continuous blood glucose monitoring. Non-invasive blood glucose assays have been promised for many years and various vibrational spectroscopy-based methods of the skin are candidates for achieving this goal. Due to the small spectral signatures of the glucose hidden among a largely variable background, the largest signal-to-noise ratios and multivariate calibration are essential to provide the method applicability for self-monitoring of blood glucose. Besides multiparameter approaches, recently presented devices based on photoplethysmography with wavelengths in the visible and near-infrared range are evaluated for their potential of providing reliable blood glucose concentration predictions. KW - Non-invasive glucose sensing KW - Vibrational spectroscopy KW - Photoplethysmography KW - Multivariate calibration KW - Validation studies PY - 2019 DO - https://doi.org/10.1007/s00216-018-1395-x SN - 1618-2650 SN - 1618-2642 VL - 411 IS - 1 SP - 63 EP - 77 PB - Springer-Verlag GmbH Germany, part of Springer Nature AN - OPUS4-46714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -