TY - JOUR A1 - Krause, Martin A1 - Milmann, Boris A1 - Mielentz, Frank A1 - Streicher, Doreen A1 - Redmer, Bernhard A1 - Mayer, K. A1 - Langenberg, K.-J. A1 - Schickert, M. T1 - Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study of Interfaces at Artificial Grouting Faults and Its Verification N2 - This paper presents the progress of successful location of grouting faults in tendon ducts with ultrasonic imaging. The examples were obtained in the research group FOR 384 funded by DFG (German Research Foundation). The co-operation of experimental research and modeling allowed imaging and identification of grouted and ungrouted areas of tendon ducts (including strands) in a large test specimen (40 m²). In addition to the criteria for indicating grouting faults in post-tensioned ducts known until now the phase evaluation of reflected ultrasonic pulses is described. Experiments and modeling of wave propagation are presented for reflections at metal plates in concrete (thickness range 0.5 mm to 40 mm) and for tendon ducts including strands. The main part of the progress was achieved by automated measurements using dry contact transducers, 3D-SAFT reconstruction including phase evaluation and modeling considering wave propagation for typical elastic parameters and exact experimental site conditions. The results for shear waves as well as for pressure waves are compared in the frequency range from 50 kHz to 120 kHz. KW - Non-destructive testing KW - Tendons KW - Prestressed concrete bridges KW - Ultrasonic echo KW - Reconstruction calculation KW - 3D-SAFT KW - Modeling (EFIT) PY - 2008 DO - https://doi.org/10.1007/s10921-008-0033-5 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 67 EP - 82 PB - Plenum Press CY - New York, NY AN - OPUS4-17922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mayer, K. A1 - Langenberg, K.-J. A1 - Krause, Martin A1 - Milmann, Boris A1 - Mielentz, Frank T1 - Characterization of reflector types by phase-sensitive ultrasonic data processing and imaging N2 - Ultrasonic and radar imaging techniques are limited in resolution by the wavelength in the material, yet information beyond those limits is hidden in complex frequency dependent reflection coefficients. The analysis of the phase of complex reflection coefficients together with the properties of imaging algorithms can help to characterize and to classify indications of defects in concrete buildings. This paper describes a method to extract phase information from measurements and SAFT reconstructed images. The influencing factors like material properties, transducer characteristics, and imaging algorithms based on Born or Physical Optics approximations are elaborated. Simulated and experimental results are briefly discussed. KW - NDT KW - Imaging KW - Flaw characterization KW - Tendon ducts KW - Phase analysis KW - Ultrasonic echo KW - SAFT KW - FT-SAFT KW - EFIT-modeling KW - Modellierung KW - EFIT KW - Spannbeton KW - Ultraschallecho KW - Spannkanäle KW - Verpressfehler KW - Zerstörungsfreie Prüfung im Bauwesen KW - ZfP-Bau PY - 2008 DO - https://doi.org/10.1007/s10921-008-0035-3 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 35 EP - 45 PB - Plenum Press CY - New York, NY AN - OPUS4-17926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bothe, Martin A1 - Mya, K.Y. A1 - Lin, E.M.J. A1 - Yeo, C. C. A1 - Lu, X. A1 - He, C. A1 - Pretsch, Thorsten T1 - Triple-shape properties of star-shaped POSS-polycaprolactone polyurethane networks N2 - Here, we present an investigation of the triple-shape properties of star-shaped polyhedral oligomeric silsesquioxane-poly(ε-caprolactone) polyurethanes (SPOSS-PUs), which have three-dimensional network structures. In a typical 'triple-shape functionalization process', mostly consisting of two tensile deformations at different temperatures, chain immobilization of the polymer network component poly(ε-caprolactone) (PCL) was successfully realized first through crystallization and then through vitrification. Subsequently, large parts of the respective strains were released under stress-free recovery conditions. The two-fold fixed ('programmed') specimens responded to heating with two independent length contractions (switching steps); the first shape change was associated with PCL devitrification and the second one with the melting of hitherto crystalline PCL. It was revealed that the triple-shape properties of SPOSS-PU networks considerably depend on PCL network chain length. When applying exactly the same 'triple-shape creation procedure', larger strain releases were detected in the first transition for polymers with a higher PCL network chain length, whereas the second transition was more accentuated for SPOSS-PU networks with a shorter PCL chain length. In the course of thermo-mechanical cycling, the formation of a neck during the second tensile deformation was repeatedly detected for SPOSS-PUs with higher PCL network chain length; in the subsequent recovery process the specimens even exhibited the highest total strain recoverability. Finally, gradual strain release could be achieved at temperatures below the PCL melting transition through the selection of up to four temperature holding steps, at which every time stable shapes were formed. KW - Shape memory polymer KW - Active polymer KW - Triple-shape polymer KW - Hybrid star-shaped polymer KW - POSS-polycaprolactone polyurethanes KW - Thermo-mechanical properties PY - 2012 DO - https://doi.org/10.1039/c1sm06474f SN - 1744-683X VL - 8 IS - 4 SP - 965 EP - 972 PB - RSC Publ. CY - Cambridge AN - OPUS4-25260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Colla, Camilla A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Höhberger, H.-J. A1 - Sommer, H. T1 - Combination of NDT techniques for site investigation of non-ballasted railway tracks N2 - Today's civil engineering NDT needs are for quantitative, fast to apply and easy to interpret methods. They are required on site both for evaluation of existing structures/infrastructure and for quality control in new construction. With this purpose, BAM has carried out in-situ feasibility studies, using radar, impact-echo and ultrasonic-echo methods. Two examples are given of their combined application on different railway slab–track constructions, using high frequency radar, scanning impact-echo and ultrasonic array methods. The aim was to evaluate limitations and advantages, comparability and complementarity of these methods. The on-site measurements demonstrated the possibility to investigate, with good accuracy via NDT, the bonding conditions between sleepers and slab, to locate voids and measure layer thickness. The acoustic and electromagnetic methods used, were found to be complementary. KW - Concrete KW - NDT KW - Impact echo KW - Ultrasonics KW - Radar KW - Railway PY - 2002 DO - https://doi.org/10.1016/S0963-8695(01)00033-0 SN - 0963-8695 VL - 35 SP - 95 EP - 105 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-1858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Ding, Yi A1 - Harrison, W.J. A1 - Budd, P.M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility and gas transport properties of nanocomposites based on PIM-1 and polyhedral oligomeric phenethyl-silsesquioxanes (POSS) N2 - Polymers with intrinsic microporosity (PIMs) are of great interest in the field of gas separation membranes. Already the first synthesized PIM-1 shows extraordinary permeability and selectivity. Unfortunately, PIM-1 is susceptible to physical aging and thus gradually loses its outstanding properties. In this study a polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) was used as a nanofiller (0–40 wt%) in the PIM-1 matrix to potentially improve the gas transport properties and prevent physical aging. The molecular mobility of the solution-cast nanocomposite films was analyzed by Broadband Dielectric Spectroscopy (BDS). Furthermore, gas permeability was determined with the time lag method (0–20 bar upstream pressure) at 35 °C for N2, O2, CH4 and CO2. KW - Broadband Dielectric Spectroscopy KW - Gas separation KW - Gas permeation KW - Polymers of intrinsic microporosity KW - Nanocomposite KW - POSS KW - PIM-1 PY - 2017 DO - https://doi.org/10.1016/j.memsci.2017.02.007 SN - 0376-7388 SN - 1873-3123 VL - 529 SP - 274 EP - 285 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-39169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Ding, Yi A1 - Harrison, W.J. A1 - Budd, P.M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility of the high performance membrane polymer PIM-1 as investigated by dielectric spectroscopy N2 - The increasing demand for energy efficient separation processes fosters the development of new high performance polymers as selective separation layers for membranes. PIM-1 is the archetypal representative of the class of polymers of intrinsic microporosity (PIM) which are considered most promising in this sector, especially for gas separations. Since their introduction, PIMs stimulated a vast amount of research in this field and meanwhile evolved to the state of the art in membrane technology for gas separation. The major obstacle for extending the practical membrane application is their strong tendency to physical aging. For the first time, investigations by broadband dielectric spectroscopy (BDS) addressing molecular dynamics and conductivity in PIM 1 are presented. As chain packing during film formation from the casting solution and physical aging are key factors determining the separation performance of PIMs as membrane materials, characterization of the molecular mobility in such materials as revealed by BDS will provide valuable information for further development and optimization. KW - PIM-1 KW - BDS broadband dielectric spectroscopy KW - Relaxation KW - Membrane PY - 2016 DO - https://doi.org/10.1021/acsmacrolett.6b00209 SN - 2161-1653 VL - 5 IS - 4 SP - 528 EP - 532 PB - ACS American Chemical Society CY - Washington, DC, USA AN - OPUS4-35798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fittschen, U.E.A. A1 - Menzel, M. A1 - Scharf, O. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Buzanich, Günter A1 - Lopez, V.M. A1 - McIntosh, K. A1 - Streli, C. A1 - Havrilla, G.J. T1 - Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera N2 - Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by 'drop on demand' technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. KW - TXRF KW - Full field micro-XRF KW - Color X-ray camera PY - 2014 DO - https://doi.org/10.1016/j.sab.2014.06.025 SN - 0584-8547 SN - 0038-6987 VL - 99 SP - 179 EP - 184 PB - Elsevier CY - Amsterdam AN - OPUS4-31180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reifschneider, O. A1 - Vennemann, A. A1 - Buzanich, Günter A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Hogeback, J A1 - Köppen, C. A1 - Großgarten, M. A1 - Sperling, M. A1 - Wiemann, M. A1 - Karst, U. T1 - Revealing Silver Nanoparticle Uptake by Macrophages Using SR-μXRF and LA-ICP-MS N2 - To better study the impact of nanoparticles on both in vitro and in vivo models, tissue distribution and cellular doses need to be described more closely. Here silver nanoparticles were visualized in alveolar macrophages by means of synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μXRF) with high spatial resolution of 3 × 3 μm2. For the spatial allocation of silver signals to cells and tissue structures, additional elemental labeling was carried out by staining with eosin, which binds to protein and can be detected as bromine signal with SR-μXRF. The method was compatible with immunostaining of macrophage antigens. We found that the silver distribution obtained with SR-μXRF was largely congruent with distribution maps from a subsequent laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of the same tissue sites. The study shows a predominant, though not exclusive uptake of silver into alveolar macrophages in the rat lung, which can be modeled by a similar uptake in cultured alveolar macrophages. Advantages and limitations of the different strategies for measuring nanoparticle uptake at the single cell level are discussed. KW - Synchrotron KW - BAMline KW - XRF KW - Nanoparticle KW - Macrophagen PY - 2020 DO - https://doi.org/10.1021/acs.chemrestox.9b00507 VL - 33 IS - 5 SP - 1250 EP - 1255 PB - American Chemical Society AN - OPUS4-50855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -