TY - CONF A1 - Wosniok, Aleksander A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Kriegsmann, Andreas T1 - Distributed Fibre Optic Monitoring of Hydrogen Storage Composite Pressure Vessels for Automotive Use N2 - We present our research work on the condition monitoring of hydrogen storage composite pressure vessels using distributed fibre optic sensors. The sensing fibres are integrated into the composite structure by wrapping them over the polymer liner in the helical and circumferential direction during the manufacturing process of the carbon fibre reinforced polymer. The following use of optical backscatter reflectometry allows for continuous condition monitoring and precise detection and localization of structural damages during the entire service life. To account for the time-dependent strength degradation of the composite pressure vessels, both slow burst and ambient hydraulic cycling tests, respectively, were conducted on five 70 MPa pressure vessels with integrated fibre optic sensors. The results achieved via distributed fibre optic strain sensing demonstrate a near linear strain response to pressure suitable for sensitive condition monitoring and confirm the required robustness of the selected sensor solution. T2 - DGZfP-Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Distributed fibre optic sensor (DFOS) KW - Composite pressure vessel KW - Optical backscatter reflectometry KW - Slow burst test KW - Ambient hydraulic cycling test PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653067 DO - https://doi.org/10.58286/32344 SP - 1 EP - 8 PB - NDT.net AN - OPUS4-65306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stohl, Leonie A1 - Manninger, Tanja A1 - Dehn, Frank A1 - von Werder, Julia T1 - Understanding bioreceptivity of concrete: material design and characterization N2 - The climate crisis is driving an increasing demand for ecologically oriented concepts. In the building sector, this demand includes not only the use of environmentally friendly materials but also the greening of urban areas. One promising approach is the development of bioreceptive concrete façades, which support the growth of green biofilms directly on their surfaces. These innovative façades are anticipated to deliver benefits comparable to those of macroscopically greened façades, such as enhanced biodiversity and improved air quality, while offering the advantages of being more self-sustaining and stable systems once fully established. However, the development of bioreceptive concrete presents substantial challenges. Due to the interdisciplinarity and novelty of this field, standardized methods for material characterization and bioreceptivity assessment are currently lacking. This study proposes an approach for evaluating surface properties crucial for bioreceptivity, developed on differently structured samples of ultra-high-performance concrete (UHPC). Existing methods and standards from concrete technology are critically reviewed and, where necessary, modified to meet the unique requirements of measuring bioreceptive material properties. Special attention is given to the surface pH value and water retention characteristics, as these are essential for promoting microbial growth and ensuring the long-term stability of green biofilms. The observed surface characteristics vary according to the imprinted surface structures, offering a spectrum of material properties and enabling the evaluation of their impact on bioreceptivity. The findings presented form the foundation for subsequent laboratory weathering experiments, which will be discussed in a complementary publication. KW - Bioreceptivity KW - Concrete KW - Biofilm PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648180 DO - https://doi.org/10.1617/s11527-025-02863-y SN - 1359-5997 VL - 58 IS - 10 SP - 1 EP - 12 PB - Springer Science and Business Media LLC AN - OPUS4-64818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Pohl, Rainer A1 - Erthner, Thomas A1 - Stegemann, Robert A1 - Kreutzbruck, Marc A1 - Sergeeva-Chollet, N. T1 - Eddy current testing with high-spatial resolution probes using MR arrays as receiver N2 - Magneto-resistive (MR) sensor arrays are suited for high resolution eddy current testing (ET) of aerospace components due to two significant advantages compared to conventional coil systems. First, to obtain high spatial resolution they can be manufactured down to the µm-regime without losing their outstanding field sensitivity. Secondly, MR technology has a relatively frequency-independent sensitivity in the range of common ET-frequencies thus providing a benefit for low frequency applications. This paper presents measurements using MR array probes consisting of 32 TMR-elements (tunnel magneto resistance), an ASIC, and subsequent readout components. A source for generating the eddy currents inside the material under test is also implemented onboard of the PCB. These probes were developed in the IMAGIC-project* for detection and imaging of surface breaking defects. The performance of the new sensor system has been investigated for several mock-ups, Aluminum and Titanium plate specimens having small adjacent boreholes with diameter of 0.44 mm and micro notches in the µm-range, respectively. To compare our results we used conventional eddy current probes. The MR sensor elements have a length of around 60 µm leading to a nearly 'point like' measurement. Neighbouring boreholes (depth 0.25 mm) with a separation of 0.6 mm between their centres could be resolved with a good SNR, and more important, the boreholes could be confidently distinguished using the TMR-probes. In case of conventional probes a reliable separation was not possible. In this paper we present the MR-ET-probes of the IMAGIC consortium and a comparison with conventional techniques. *The IMAGIC-project ('Integrated Magnetic imagery based on spIntronics Components', 2011 – 2014, project reference: 288381) was funded by the European Commission, Seventh Framework Programme. Further partners involved in the consortium beside BAM and CEA were INESC-ID and INESC-MN (Portugal), Sensitec GmbH (Germany), Tecnatom S.A. (Spain), and Airbus Group (France). T2 - 7th International symposium on NDT in aerospace CY - Bremen, Germany DA - 16.11.2015 KW - TMR KW - GMR KW - Sensor array KW - Eddy current testing (ET) KW - Aerospace PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344254 SN - 978-3-940283-76-4 N1 - Serientitel: DGZfP-Proceedings – Series title: DGZfP-Proceedings IS - DGZfP-BB 156 SP - We.5.A.4, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.v. (DGZfP) AN - OPUS4-34425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maiwald, Michael A1 - Gräßer, Patrick A1 - Wander, Lukas A1 - Zientek, Nicolai A1 - Guhl, Svetlana A1 - Meyer, Klas A1 - Kern, Simon T1 - Strangers in the Night—Smart Process Sensors in Our Current Automation Landscape N2 - The departure from the current automation landscape to next generation automation concepts for the process industry has already begun. Smart functions of sensors simplify their use and enable plug-and-play integration, even though they may appear to be more complex at first sight. Smart sensors enable concepts like self-diagnostics, self-calibration, and self-configuration/parameterization whenever our current automation landscape allows it. Here we summarize the currently discussed general requirements for process sensors 4.0 and introduce a smart online NMR sensor module as example, which was developed for an intensified industrial process funded by the EU’s Horizon 2020 research and innovation programme (www.consens-spire.eu). T2 - Eurosensors 2017 Conference CY - Paris, France DA - 03.09.2017 KW - Process Monitoring KW - Smart Sensors KW - CONSENS KW - Online NMR Spectroscopy KW - Mini-plant PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-415772 UR - http://www.mdpi.com/2504-3900/1/4/628 DO - https://doi.org/10.3390/proceedings1040628 VL - 1 SP - 628 EP - 631 PB - MDPI CY - Basel AN - OPUS4-41577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Katsikini, M. A1 - Pinakidou, F. A1 - Paloura, E.C. A1 - Arvanitidis, J. A1 - Ves, S. A1 - Reinholz, Uwe A1 - Ppadomanolaki, E. A1 - Iliopoulos, E. T1 - Simulation of the EXAFS and Raman spectra of InxGa1-xN utilizing the equation of motion routine of FEFF8 N2 - A combined analysis of EXAFS and Raman spectra is applied for the study of InxGa1-xN alloys with 0.3 0.5MeV) X-rays and proved the applicability of the present technique to inspect thick carbon-fiber laminated components. In order to improve the inspection time and image quality of the backscatter image, we used high-resolution (180ìm) digital detector arrays (DDAs). At the end, important applications of the presented X-ray backscatter technique to the aerospace industry are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - X-ray backscatter imaging KW - Twisted-slit collimator KW - NDT KW - Digital detector array (DDA) KW - Stringer KW - Aerospace applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322376 UR - https://www.ndt.net/?id=16431 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartscher, M. A1 - Ehrig, Karsten A1 - Staude, Andreas A1 - Goebbels, Jürgen A1 - Neuschaefer-Rube, U. T1 - Application of an industrial CT reference standard for cast freeform shaped workpieces N2 - Industrial computed tomography (CT) today is an important method to analyze defects and to measure the geometry of technical products. The measurement capability of industrial CT often depends on the knowledge of the measurement errors being present. Only with this knowledge, effective corrections are possible by manufacturers, or adapted measurement procedures become possible for the customers. Thus, there is the strong need to have adequate reference standards both for the assessment of general dependencies and for the measurement of task-specific effects. Especially the latter are difficult to assess. This paper shows the application of a versatile dismountable workpiece-near reference body for the use with CT. The reference standard was made from a miniaturized cast aluminium (one-)cylinder head. It can be dismounted into four segments, each featuring reference geometries which enable a registration of CT measured and other reference datasets (e.g. from tactile CMM). The reference standard embodies complex freeform surfaces which are a challenging measurement task for CT and other sensors. Here the application of the reference standard is the study of the influence of material mixes. This is realized by adding pieces of other materials which disturb the mono-material measurement. Results of the application of the reference standard are presented using data from industrial micro-CT systems and CMM reference data. A special emphasis is given on the workflow of the data processing and the data analysis. T2 - International symposium on digital industrial radiology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Industrial reference standard KW - Computed tomographie KW - Freeform shaped workpieces PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-245532 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (We.4.3) SP - 1 EP - 12 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ehrig, Karsten A1 - Goebbels, Jürgen A1 - Meinel, Dietmar A1 - Paetsch, O. A1 - Prohaska, S. A1 - Zobel, Valentin T1 - Comparison of crack detection methods for analyzing damage processes in concrete with computed tomography N2 - Analyzing damages at concrete structures due to physical, chemical, and mechanical exposures need the application of innovative non-destructive testing methods that are able to trace spatial changes of microstructures. Here, the utility of three different crack detection methods for the analysis of computed tomograms of various cementitious building materials is evaluated. Due to the lack of reference samples and standardized image quality evaluation procedures, the results are compared with manually segmented reference data sets. A specific question is how automatic crack detection can be used for the quantitative characterization of damage processes, such as crack length and volume. The crack detection methods have been integrated into a scientific visualization system that allows displaying the tomography images as well as presenting the results. T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Crack detection KW - Computed tomography KW - Data visualization PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243569 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Poster 2) SP - 1 EP - 8 PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Caldeira, Rui A1 - Bartusch, Jürgen A1 - Kupnik, M. T1 - Air-coupled ultrasonic ferroelectret receiver with additional DC voltage N2 - Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air. With a lower acoustic impedance than the usual piezoelectric materials, charged cellular polypropylene film (cPP) offers better matching to air with a similar piezoelectric coefficient. The piezoelectric behaviour demonstrated by cPP comes from polarized air cells that create a permanent internal voltage. The sensitivity of the sensor varies with the application of an additional DC bias voltage. Thus, this work presents a cPP ultrasonic sensor with an improvement of up to 15 ± 1 dB on the signal-to-noise ratio. T2 - Eurosensors 2017 CY - Paris, France DA - 3.9.2017 KW - Ultrasonic KW - Air-coupled KW - Cellular polypropylene KW - Transducer KW - Ferroelectret PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419009 DO - https://doi.org/10.3390/proceedings1040362 VL - 1 IS - 4 SP - Article 362, 1 EP - 4 AN - OPUS4-41900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Kolkoori, Sanjeevareddy A1 - Bellon, Carsten T1 - Quantitative simulation of back scatter X-ray imaging and comparison to experiments N2 - X-ray backscatter imaging is a well established NDT technique to inspect complex objects using only a single-sided access. In difference to conventional transmission X-ray radiography, the X-ray backscatter imaging utilizes the scattered radiation caused by the Compton scattering effect. In order to achieve high backscatter intensities from a test object, it is necessary to optimize the backscatter system parameters namely the angle between source and slit camera, the slit collimator system, the shielding between source and scatter camera, and the type of detector. In addition, the scatter phenomena in to the investigated object need to be understood. In this contribution, we present a Monte Carlo model McRay which considers all relevant single and multiple interactions of photons and electrons. This model can be used to simulate back scatter techniques. It allows not only calculating the scatter image for a given experimental setup but also registering the spectrum of the detected scattered photons. Both aspects are important to understand the imaging process, to interpret the results, and to optimize the backscatter camera investigated here. Additionally experimental results will be presented and compared with simulations. T2 - 19th World Conference on Nondestructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Radiology KW - Back-scatter techniques KW - Simulation KW - Monte Carlo methods KW - Measurements PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365897 SN - 978-3-940283-78-8 VL - 158 SP - 1 EP - 11 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP) CY - Berlin, Germany AN - OPUS4-36589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter A1 - Krebs, Holger T1 - Boiling liquid expanding vapour explosion (BLEVE) of peroxy-fuels: Experiments and computational fluid dynamics (CFD) simulation N2 - Fire and explosion hazards associated with storage and transportation of flammable materials have been a matter of great interest in the recent times. BLEVE is a scenario that occurs when a closed fuel container is subjected to heat for a longer duration. Such events are disastrous to human beings and assets both. In the past there have been numerous studies on BLEVEs and fireballs of hydrocarbon fuels, e.g. kerosene, gasoline, LPG, LNG and others. Though, the fireballs of peroxy-fuels are not looked into detail as such. This article tries to overcome this lack of knowledge. Both, experimental investigation and CFD simulations are performed to measure and predict the fireball characteristics of a peroxy-fuel. Due to thermal decomposition in the liquid phase and active oxygen content a peroxy-fuel fireball burns at a very fast rate and emit higher thermal radiation whereas exhibits smaller diameter and elevation compared to hydrocarbons. That eventually leads to consideration of larger safety distances from them which are also verified by CFD results. KW - BLEVE KW - Hydrocarbons KW - Peroxy-fuels KW - Safety distances KW - CFD simulation PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334184 DO - https://doi.org/10.1016/j.egypro.2015.02.082 SN - 1876-6102 VL - 66 SP - 149 EP - 152 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-33418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraehnert, R. A1 - Ortel, Erik A1 - Paul, B. A1 - Eckhardt, B. A1 - Kanis, M. A1 - Liu, R. A1 - Antoniou, A. T1 - Electrochemically dealloyed platinum with hierarchical pore structure as highly active catalytic coating N2 - Micro structured reactors are attractive candidates for further process intensification in heterogeneous catalysis. However, they require catalytic coatings with significantly improved space-time yields compared to traditional supported catalysts. We report the facile synthesis of homogeneous nanocrystalline Pt coatings with hierarchical pore structure by electrochemical dealloying of amorphous sputter-deposited platinum silicide layers. Thickness, porosity and surface composition of the catalysts can be controlled by the dealloying procedure. XPS analysis indicates that the catalyst surface is primarily composed of metallic Pt. Catalytic tests in gas-phase hydrogenation of butadiene reveal the typical activity, selectivity and activation energy of nanocrystalline platinum. However, space time yields are about 13 to 200 times higher than values reported for Pt-based catalysts in literature. The highly open metallic pore structure prevents heat and mass transport limitations allowing for very fast reactions and reasonable stability at elevated temperatures. KW - Pt catalysts KW - Pt–Si layers KW - Scanning Electron Microscopy (SEM) KW - Transmission Electron Microscopy (TEM) KW - pore structure KW - electrochemical dealloying PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351393 DO - https://doi.org/10.1039/C4CY00851K SN - 2044-4753 SN - 2044-4761 VL - 5 IS - 1 SP - 206 EP - 216 PB - RSC Publ. CY - Cambridge AN - OPUS4-35139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, Felix A1 - Agirrezabal-Telleria, Iker A1 - Jäger, Christian A1 - Kemnitz, E. T1 - Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy N2 - Lewis and Brønsted sites were quantified in a series of weak acidic hydroxylated magnesium fluorides by Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance spectroscopy (NMR) with pyridine as probe molecule. Molar extinction coefficients, which are necessary for quantitative FTIR measurements, were calculated by an easy approach. It utilizes the fact that both signals, used for the quantification by FTIR, are caused by the same deformation vibration mode of pyridine. Comparison of quantitative FTIR experiments and quantification by NMR shows that concentrations of acidic sites determined by FTIR spectroscopy have to be interpreted with caution. Furthermore, it is shown that the transfer of molar extinction coefficients from one catalyst to another may lead to wrong results. Molar extinction coefficients and concentrations of acidic sites determined by FTIR spectroscopy are affected by grinding and probably the particle size of the sample. High temperature during FTIR experiments has further impact on the quantification results. KW - Acidity KW - Fluoride catalyst KW - Infrared spectroscopy KW - Adsorption of pyridine KW - Molar extinction coefficient determination PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351448 DO - https://doi.org/10.1039/C5RA15116C SN - 2046-2069 VL - 5 IS - 109 SP - 89659 EP - 89668 PB - RSC Publishing CY - London AN - OPUS4-35144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bellon, Carsten A1 - Gollwitzer, Christian A1 - Fratzscher, Daniel A1 - Ewert, Uwe A1 - Jaenisch, Gerd-Rüdiger T1 - Simulation of complex scan paths for 3D reconstruction N2 - X-ray computed tomography (CT) is a volumetric (3D) Imaging diagnostic method, well established in the medical field, and in industrial NDE as well. Developments in industrial CT aim to extent the applicability to complex structures, which do not allow the access of all directions. This are e.g. limited view, data and angle CT applications. New reconstruction algorithms are required on one side, and the accuracy has to be improved on the other side. Numerical Simulation can support such developments by providing well defined data sets for the testing of reconstruction algorithms. This approach of virtual CT is realized within the radiographic simulator aRTist, developed by BAM. The poster shows the possibilities of this tool to consider complex scan paths. Simulated data sets have been reconstructed by an versatile backprojection algorithm. T2 - International symposium on digital industrial radiology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Radiographie KW - Computer-Simulation KW - 3D-Rekonstruktion PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243928 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Poster 17) SP - 1 EP - 4 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abbott, A. P. A1 - Abolibda, T. Z. A1 - Davis, S.J. A1 - Emmerling, Franziska A1 - Lourdin, D. A1 - Leroy, E. A1 - Wise, W. R. T1 - Glycol based plasticisers for salt modified starch N2 - Starch is one of the most common and easily obtained natural polymers, making it attractive as a potential bio-based alternative to synthetic polymers. This study shows that a simple quaternary ammonium salt combined with urea or glycols forms effective modifiers that produce flexible plastics with good mechanical properties that are comparable to some polyolefin plastics. The processing conditions are shown to significantly affect the structure of the polymer which has a concomitant effect upon the mechanical and physical properties of the resulting plastic. Using a glycerol based modifier results in a totally sustainable and biodegradable material which can be injection moulded. KW - biodegradable material KW - flexible plastics KW - injection moulded PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351426 DO - https://doi.org/10.1039/C4RA06220E SN - 2046-2069 VL - 4 IS - 76 SP - 40421 EP - 40427 PB - RSC Publishing CY - London AN - OPUS4-35142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Ewert, Uwe A1 - Jaenisch, Gerd-Rüdiger T1 - On POD estimations with radiographic simulator aRTist N2 - The computer simulation of radiography is applicable for different purposes in NDT such as for the qualification of NDT systems, the optimization of system parameters, feasibility analysis, model-based data interpretation, education and training of NDT/NDE personnel, and others. Within the framework of the European project PICASSO simulators will be adapted to support reliability assessments of NDT tasks. The radiographic simulator aRTist developed by BAM is well suited for this task. It combines analytical modelling of the RT inspection process with the CAD-orientated object description applicable to various industrial sectors such as power generation, aerospace, railways and others. The analytic model includes the description of the radiation source, the interaction of Radiation with the material of the part, and the detection process with special focus to DIR. To support reliability estimations the simulation tool is completed by a tool for probability of detection (POD) estimation. It consists of a user interface for planning automatic simulation runs with varying parameters, specifically defect variations. Further, an automatic image analysis procedure is included to evaluate the defect visibility and calculate the POD therefrom. T2 - International symposium on digital industrial radiology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Radiographie KW - Computersimulation KW - Probability of detection PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-245092 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Tu.2.3) SP - 1 EP - 8 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sötebier, Carina A. A1 - Kutscher, D. J. A1 - Rottmann, L. A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Bettmer, J. T1 - Combination of single particle ICP-QMS and isotope dilution analysis for the determination of size, particle number and number size distribution of silver nanoparticles N2 - Single particle ICP-MS (spICP-MS) has gained great influence in the analysis of engineered nanoparticles (NPs) due to its simplicity, speed and ability to obtain a particle number size distribution. Despite its many advantages, the method is hampered by matrix effects affecting the sensitivity of the instruments. Consequently, over- or underestimated particle sizes might be obtained. To overcome these challenges, we present in this work the detection of both Ag isotopes with a quadrupole mass spectrometer for the application of isotopic dilution analysis (IDA) in combination with spICP-MS. Here, the isotopes are measured sequentially using the conventional spICP-MS integration time of 10 ms. Citrate stabilized Ag NPs of a spherical shape with the nominal diameters of 30, 40, 50 and 80 nm have been investigated. The experimental concept of adding ¹⁰⁹Ag+ solutions to the NP suspensions resulted in the NP Spikes being only visible in the ¹⁰⁷Ag trace. Therefore, a maximum of 45% of the particles was detected compared to that by conventional spICP-MS. A modified mass flow equation was applied to determine the particle sizes, particle size distributions and particle number concentrations of various Ag NPs. The addition of different spike concentrations between 0.5 and 4 mg L⁻¹ ¹⁰⁹Ag resulted in similar particle diameters, suggesting that the calculated diameter might be independent of the spike concentration. This would have the advantage that no size information would be needed before the analysis. By analyzing Ag NP suspensions in a simulated seawater matrix, we demonstrate its significant influence on the particle size determination using conventional spICP-MS. A lower transport efficiency of 6.1% was found in the matrix compared to 7.3% without the matrix. In our approach, the addition of the Matrix influenced the NP intensity stronger than the spike signal, resulting in slightly smaller diameters using IDA–spICP-MS with the matrix compared to the results without the matrix. On the other hand, the IDA–spICP-MS approach with the matrix can result in equivalent results for the particle sizes compared with conventional spICP-MS using suspensions without the matrix. Due to the lower instrument sensitivity in the matrix, a diameter of 30 nm was found to be close to the detection limit of the instrument. KW - Ag nanoparticles KW - Single particle ICP-MS KW - Matrix influence KW - Isotope dilution analysis PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376490 DO - https://doi.org/10.1039/c6ja00137h SN - 0267-9477 VL - 31 IS - 10 SP - 2045 EP - 2052 AN - OPUS4-37649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neubert, Sebastian A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Experimental determination of TRIP parameter K for mild- and high strength low alloy steels and a super martensitic filler material N2 - A combined experimental numerical approach is applied to determine the transformation induced plasticity (TRIP)-parameter K for different strength low-alloy steels of grade S355J2+N and S960QL as well as the super martensitic filler CN13-4-IG containing 13 wt% chromium and 4 wt% nickel. The thermo-physical analyses were conducted using a Gleeble® 3500 facility. The thermal histories of the specimens to be tested were extracted from corresponding simulations of a real gas metal arc weldment. In contrast to common TRIP-experiments which are based on complex specimens a simple flat specimen was utilized together with an engineering evaluation method. The evaluation method was validated with literature values for the TRIP-parameter. It could be shown that the proposed approach enables a correct description of the TRIP behavior. KW - Transformation induced plasticity (TRIP) KW - Phase transformation KW - High-strength low-alloy steel KW - Super martensitic filler material KW - Thermo physical simulation KW - Gleeble experiments PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367297 DO - https://doi.org/10.1186/s40064-016-2474-0 VL - 5 IS - 575 SP - Paper 754, 1 EP - 16 PB - SpringerPlus AN - OPUS4-36729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tölle, Florian A1 - Gumenyuk, Andrey A1 - Gebhardt, Moritz Oliver A1 - Rethmeier, Michael T1 - Post-weld residual stress mitigation by scanning of a defocused laser beam N2 - High welding residual stresses can cause service life reducing consequences. Even though many processes have been developed to reduce these stresses, they are only applicable for wider welds and simple component geometries or are cost-intensive, respectively. The presented method uses a defocused beam after welding for heating the material regions on both sides of the weld. In this way, the welding stresses are decreased without contacting the surfaces using the available equipment. Different process parameters could be used depending on the component geometry and the laser power. The mechanism and the influence of the process parameters were investigated by FEM-simulation and experiments on S355J2+N steel and showed a stress reduction of about 73%. T2 - Lasers in Manufacturing 2011 - Proceedings of the Sixth International WLT Conference on Lasers in Manufacturing CY - Munich, Germany DA - 23.05.2011 KW - Residual stresses KW - Stress reduction KW - High energy beam welding KW - Post-weld heat treatment KW - Laser scanner optics PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-238482 DO - https://doi.org/10.1016/j.phpro.2011.03.052 SN - 1875-3892 VL - 12 IS - 1 SP - 410 EP - 418 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-23848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bellon, Carsten A1 - Hohendorf, Stefan A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Nusser, A. A1 - Freitag, M. A1 - Bücherl, T. A1 - Bar, D. A1 - Mor, I. A1 - Tamin, N. A1 - Weiss-Babai, R. A1 - Bromberger, B. A1 - Dangendorf, V. A1 - Tittelmeier, K. T1 - Computed tomography with X-rays and fast neutrons for restoration of wooden artwork N2 - The objects of this investigation were sculptures taken from a ca. three hundred years old baroque epitaph of a church in Tonning, a town in Northern Germany. Around 1900 it was found in a disastrous state heavily damaged by wood-worm. At that time, the whole artwork was treated with the tar extract carbolineum as a remedy. Nowadays, this substance has been identified as carcinogenic, and its presence can be perceived by its stench and visually at certain spots on the surface where it has penetrated the covering paint. A gold-painted sculpture of a massive wooden skull was interrogated with X-rays and fast neutrons to investigate the internal distribution of the carbolineum. The X-ray tomography, with its excellent spatial resolution revealed galleries left over from the worm infestation in the outer areas and cracks in the central region. The golden color coating appeared as a thick and dense layer. In comparison the tomography with fast neutrons, though being of lower resolution and yet unresolved artefacts revealed sections of slightly different densities in the bulk of the wood. These differences we attribute to the differences in the distribution of the impregnant in the wood, visible due to its higher hydrogen content making it less transparent for neutrons. T2 - WCNR-10 - 10th World conference on neutron radiography CY - Grindelwald, Switzerland DA - 05.10.2014 KW - Computed tomography KW - Neutron radiology KW - Conservation of wooden artwork PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323050 DO - https://doi.org/10.1016/j.phpro.2015.07.066 SN - 1875-3892 VL - 69 SP - 472 EP - 477 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ö. A1 - Avilov, V. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Full penetration hybrid laser arc welding of up to 28 mm thick S355 plates using electromagnetic weld pool support N2 - The laser hybrid welding process offers many advantages regarding deep penetration, increased welding velocity and with the help of the supplied filler wire an improved bridgeability to gap and misalignment tolerances. High power laser systems with a power of approx. 30 kW are already available on the market. Nevertheless, multi-layer technology with an arc process is still used for welding of plates from a thickness from 20 mm. A potential cause is the process instability with increasing laser power. It is inevitable that gravity drop-out due to the high hydrostatic pressure at increasing wall thickness especially at welding in flat position and with a low welding speed. The surface tension decreases with increasing root width resulting from low welding velocities. To prevent such inadmissible defects of the seam a use of weld pool support is required. Usual weld pool support systems such as ceramic or powder supports require a mechanical detachment which is time-consuming. The electromagnetic weld pool support system described in this work shows an alternative weld pool support which works contactless. It is based on generating Lorentz forces in the weld pool due to oscillating magnetic field and induced eddy currents. This innovative technology offers single pass welds up to 28 mm in flat position and reduced welding velocity with a laser power of just 19 kW. It also leads to improved mechanical-technological properties of the seams because of the slow cooling rate. With usage of an electromagnetic weld pool support the limitation of the hybrid laser arc welding process in the thick sheet metal will be extend. KW - Electromagnetic weld pool support KW - Hybrid laser arc welding KW - Thick-walled steel KW - Single pass welding PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468276 DO - https://doi.org/10.1088/1742-6596/1109/1/012015 SN - 1742-6596 VL - 1109 SP - 1 EP - 7 PB - IOP Publ. AN - OPUS4-46827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dmitriev, A. I. A1 - Österle, Werner ED - Österle, Werner ED - Zhang, G. T1 - The role of solid lubricants for brake friction materials N2 - This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol.% of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and a minimum of wear. KW - Solid lubricant KW - Friction KW - Automotive braking KW - Tribofilm KW - Sliding simulation KW - MCA-modeling PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355973 UR - www.mdpi.com/journal/lubricants DO - https://doi.org/10.3390/lubricants4010005 SN - 2075-4442 VL - 4 IS - 1 SP - 5 EP - 26 PB - MDPI CY - Basel, Switzerland AN - OPUS4-35597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Manuel A1 - Klimakow, Maria A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Fast and efficient synthesis of a host guest system: a mechanochemical approach N2 - An unusually fast and effective synthesis procedure for a host guest system consisting of a metal organic framework (MOF) and a polyoxometalate (POM) is described. The material was synthesised mechanochemically and the evolution of the structure was monitored ex and in situ using synchrotron X-ray diffraction (XRD). KW - Mechanochemistry KW - MOF KW - in situ PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354910 UR - http://pubs.rsc.org/en/Content/ArticleLanding/2016/CE/C5CE01868D#!divAbstract DO - https://doi.org/10.1039/C5CE01868D VL - 18 IS - 7 SP - 1096 EP - 1100 AN - OPUS4-35491 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Bischof, Eik A1 - Taffe, A. T1 - Multi-sensor investigation of concrete moisture using ultrasound, radar and microwave N2 - Moisture and salt loads of concrete can significantly change its microstructure and consequently lead to chemical and mechanical degradation. However, the non-destructive investigation of moisture and salt present in concrete is still difficult. In order to address and compare the sensitivity of different methods concrete samples with different pore systems realized by varying the w/z ratios have been fabricated. The focus of this study was put on the analysis of ultrasonic long and trans waves measured on the surface and in transmission mode. The results show clear dependencies of all applied methods. With the radar and microwave methods predominantly changes in the concrete moisture could be detected, whereas the different pore systems were not observed to alter the signals. In contrast for the ultrasound method also the ongoing hydration as well as the nature of the pore system strongly influenced the signals. As a consequence in a subsequent drying experiment it was also tried to delineate the effects of moisture and hydration. All specimens have been re-saturated under pressure and the drying experiment was repeated using the same multi-sensor approach. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Concrete KW - Moisture KW - Non-destructive testing KW - Ultrasound KW - Radar KW - Velocities KW - Microwave KW - Multi-sensor approach PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347612 UR - http://www.ndt.net/?id=18322 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Feldmann, Rüdiger T1 - Comparison of non-destructive moisture measurement methods on cement and calcium sulphate based screed samples N2 - Measuring the moisture content of floor screeds is usually done with minor destructive testing methods like Darr drying or the Calcium Carbid (CM) method. These require small samples, deliver only punctual information and still have proven not to be very reliable. Hence, a study has been made using the standard destructive tests as well as a suite of non-destructive testing methods working out their use for moisture determination. In this study five partners from research institutes and industry worked together and intensively researched different technologies. The main focus was put on the varying sensitivity of the measuring techniques in different moisture ranges. Especially for low moisture contents ( or ‘critical’ moisture contents when the screed is dry enough to be covered with the final floor finish), several commercial devices including the most commonly used CM-method failed to determine the correct moisture content for cementitious samples. Hence the need for more accurate, if possible non-destructive methods is high, taking also into account that the chemistry (and physical properties) of screeds may vary strongly depending on their origin and purpose. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Screed KW - Moisture KW - Non-destructive testing KW - Radar KW - Capacitive methods KW - Resistivity KW - Multi-sensor KW - Electrics KW - Monitoring PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347602 UR - http://www.ndt.net/?id=18368 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fasano, A. A1 - Woyessa, G. A1 - Stajanca, Pavol A1 - Markos, C. A1 - Stefani, A. A1 - Nielsen, K. A1 - Rasmussen, H. K. A1 - Krebber, Katerina A1 - Bang, O. T1 - Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors N2 - Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C. We also characterize the mPOF optically and mechanically, and further test the sensitivity of the PC FBG to strain and temperature. We demonstrate that the PC FBG can bear temperatures as high as 125°C without malfunctioning. In contrast, polymethyl methacrylate-based FBG technology is generally limited to temperatures below 90°C. KW - Fiber optics sensors KW - Fiber Bragg gratings KW - Microstructured fibers KW - Fiber characterization KW - Polymers PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355591 DO - https://doi.org/10.1364/OME.6.000649 SN - 2159-3930 VL - 6 IS - 2 SP - 649 EP - 659 PB - OSA Publishig AN - OPUS4-35559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Mauke, R. A1 - Effner, Ute A1 - Milmann, Boris A1 - Völker, Christoph A1 - Wiggenhauser, Herbert T1 - Ultrasonic testing of a sealing construction made of salt concrete in an underground disposal facility for radioactive waste N2 - For the closure of radioactive waste disposal facilities engineered barriers- so called “drift seals” are used. The purpose of these barriers is to constrain the possible infiltration of brine and to prevent the migration of radionuclides into the biosphere. In a rock salt mine a large scale in-situ experiment of a sealing construction made of salt concrete was set up to prove the technical feasibility and operability of such barriers. In order to investigate the integrity of this structure, non-destructive ultrasonic measurements were carried out. Therefore two different methods were applied at the front side of the test-barrier: 1 Reflection measurements from boreholes 2 Ultrasonic imaging by means of scanning ultrasonic echo methods This extended abstract is a short version of an article to be published in a special edition of ASCE Journal that will briefly describe the sealing construction, the application of the non-destructive ultrasonic measurement methods and their adaptation to the onsite conditions -as well as parts of the obtained results. From this a concept for the systematic investigation of possible contribution of ultrasonic methods for quality assurance of sealing structures may be deduced. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 2015-09-15 KW - Ultrasonic reflection measurement KW - Dry contact transducers in boreholes KW - Interface salt-concrete / rock salt KW - Ultrasonic imaging of internal reflectors PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346203 UR - http://www.ndt.net/?id=18304 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grothe, Sven T1 - Ultrasonic signal evaluation used to detect temperature changes in a concrete specimen caused by a heating system N2 - Ultrasonic measurement evaluation methods have been proven to be effective for detection of subtle changes, caused by temperature, load or moisture. To detect and localize temperature changes, a concrete block of 4 × 5 × 0.8 m3, including a heating cartridge and multiple temperature sensors, has been set up to change the temperature and monitor the temperature distribution in a certain area inside the specimen. An ultrasonic monitoring system with 40 ultrasonic sensors (20 transmitters, 20 receivers, 25 kHz central frequency) has been implemented on the specimen. Data from 400 sensor combinations was collected over the whole period of the experiment in an interval of 30 minutes. Quantitative methods (CodaWave Interferometry and Time of Flight method) were used to evaluate the changes in ultrasonic travel-time caused by the heating period, when the cartridge was active, and the cooling period after turning off the cartridge. Furthermore the travel-time changes from all 400 sensor combinations were used to locate the heating cartridge. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346387 UR - http://www.ndt.net/?id=18336 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bellon, Carsten A1 - Jaenisch, Gerd-Rüdiger A1 - Deresch, Andreas T1 - Combining analytical and Monte Carlo modelling for industrial radiology N2 - Modelling becomes more and more important in modern NDE. It is increasingly used to optimize techniques for complex applications, to support the preparation of written procedures, and for education purposes. To describe the complete chain of RT, the model includes simulating all necessary properties of X- or Gamma-ray sources, the interaction of photons with material with special attention to scattered radiation, the detection process, and the complete geometrical RT setup handling arbitrary parts or constructions. Depending on the given inspection problem and the influencing factors that should be addressed by the simulation, an appropriate physical model has to be chosen to describe the underlying interaction mechanisms. The simulator aRTist combines analytical and Monte Carlo methods to efficiently model the radiation transport such that transmission as well as scatter techniques can be modelled. In this contribution we Focus on Monte Carlo Simulation of scatter contribution within aRTist. Examples for RT/tomographic applications and back-scatter techniques are presented to demonstrate the usability of the presented simulation tool for a broad range of radiological applications. T2 - 19th Wolrd Conference on Nondestructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Radiography KW - Computed tomography KW - Simulation KW - Monte Carlo methods PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365856 SN - 978-3-940283-78-8 VL - 158 SP - 1 EP - 9 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP) CY - Berlin, Germany AN - OPUS4-36585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Petrat, T. A1 - Graf, B. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael ED - Schmidt, M. ED - Vollertsen, F. ED - Arnold, C. B. T1 - Laser metal deposition as repair technology for a gas turbine burner made of Inconel 718 N2 - Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition. T2 - LANE - 9 International Conference on Photonic Technologies CY - Fürth, Germany DA - 19.09.2016 KW - Laser metal deposition KW - Inconel 718 KW - Additive manufacturing KW - Maintenance KW - Repair and overhaul PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376723 UR - http://ac.els-cdn.com/S1875389216301857/1-s2.0-S1875389216301857-main.pdf?_tid=ed1d75de-84a2-11e6-af94-00000aab0f6c&acdnat=1474974777_4917d753cb3d316c4b000ba0760778b5 DO - https://doi.org/10.1016/j.phpro.2016.08.078 SN - 1875-3892 VL - 83 SP - 761 EP - 768 PB - Elservier AN - OPUS4-37672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neukammer, J. A1 - Hussels, M. A1 - Kummrow, A. A1 - Devonshire, A. A1 - Foy, C. A1 - Huggett, J. A1 - Parkes, H. A1 - Zel, J. A1 - Milavec, M. A1 - Schimmel, H. A1 - Unger, Wolfgang A1 - Akgoz, M. A1 - McHugh, V. A1 - Grunert, H.-P. A1 - Zeichhardt, H. T1 - Survey results on nucleic acid tests of infectious diseases: present status and need for rapid and patient near diagnostics N2 - This survey will discuss current and emerging isothermal and rapid polymerase chain reaction (PCR) based nucleic acid amplification methods for patient near diagnostics. To assess the clinical need of rapid diagnostics for infectious diseases based on nucleic acid tests (NATs) we performed and analysed a questionnaire among laboratories participating in corresponding INSTAND ring trials for external quality assurance. The questions concerning new amplification technologies like isothermal nucleic acid amplification, potentially suited to significantly decrease turnaround times, were complemented by questions to evaluate the present status of NATs. Besides end-users, companies were also addressed by sending out a manufacturer specific questionnaire. Analysis of the answers from 48 laboratories in 14 European countries revealed that a much shorter turnaround time is requested for selected pathogens compared to about 2 h or longer when applying temperature cycling amplification, i.e. PCR. In this context, most frequently mentioned were MRSA, norovirus, influenza A and B viruses, cytomegalovirus (CMV) as well as hepatitis B virus (HBV) and hepatitis C virus (HCV). At present, 8% of the laboratories having participated in this survey apply isothermal amplification of nucleic acid to identify infectious pathogens. KW - Nucleic acid tests KW - Infectious diseases KW - Virus detection KW - Bacteria detection KW - Isothermal nucleic acid amplification KW - Status report KW - Questionnaire KW - NAT KW - PCR PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:0183-lab0000160 UR - http://www.egms.de/static/en/journals/lab/2015-6/lab000016.shtml DO - https://doi.org/10.3205/lab000016 SN - 1869-4241 VL - 6 SP - 1 EP - 11 PB - GMS CY - Düsseldorf AN - OPUS4-36133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Matkovic, A. A1 - Vasic, B. A1 - Pesic, J. A1 - Prinz, J. A1 - Bald, Ilko A1 - Milosavljevic, A. R. A1 - Gajic, R. T1 - Enhanced structural stability of DNA origami nanostructures by graphene encapsulation N2 - Wedemonstrate that a single-layer graphene replicates the shape ofDNAorigami nanostructures very well. It can be employed as a protective layer for the enhancement of structural stability of DNA origami nanostructures. Using the AFM based manipulation, we show that the normal force required to damage graphene encapsulated DNA origami nanostructures is over an order of magnitude greater than for the unprotected ones. In addition, we show that graphene encapsulation offers protection to the DNA origami nanostructures against prolonged exposure to deionized water, and multiple immersions. Through these results we demonstrate that graphene encapsulated DNA origami nanostructures are strong enough to sustain various solution phase processing, lithography and transfer steps, thus extending the limits of DNA-mediated bottom-up fabrication. KW - atomic force microscopy KW - graphene KW - DNA origami nanostructures PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358741 UR - http://iopscience.iop.org/article/10.1088/1367-2630/18/2/025016 DO - https://doi.org/10.1088/1367-2630/18/2/025016 SN - 1367-2630 VL - 18 SP - 025016 PB - IOP PUBLISHING LTD CY - Bristol, UK AN - OPUS4-35874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weller, Michael G. T1 - Quality issues of research antibodies N2 - According to several recent studies, an unexpectedly high number of landmark papers seem to be not reproducible by Independent laboratories. Nontherapeutic antibodies used for research, diagnostic, food analytical, environmental, and other purposes play a significant role in this matter. Although some papers have been published offering suggestions to improve the situation, they do not seem to be comprehensive enough to cover the full complexity of this issue. In addition, no obvious improvements could be noticed in the field as yet. This article tries to consolidate the remarkable variety of conclusions and suggested activities into a more coherent conception. It is concluded that funding agencies and journal publishers need to take first and immediate measures to resolve these problems and lead the way to a more sustainable way of bioanalytical research, on which all can rely with confidence. KW - reproducibility crisis KW - irreproducibility KW - replication KW - paper retraction KW - peer reviewimmunochemistry KW - immunoassay KW - ligand binding assay KW - monoclonal antibody KW - quality control KW - cross-reactivity KW - non-specific binding KW - selectivity PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-356254 DO - https://doi.org/10.4137/ACI.S31614 SN - 1177-3901 VL - 11 SP - 21 EP - 27 PB - Libertas Academica CY - Auckland, New Zealand AN - OPUS4-35625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kopyra, J. A1 - Keller, A. A1 - Bald, Ilko T1 - On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy N2 - Gemcitabine (2',2'-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2'-deoxycytidine, 2'-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA. KW - Dissociative electron attachment KW - DNA radiation damage KW - Gemcitabine KW - DNA radiosensitizer KW - Tumor radiation therapy PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302872 DO - https://doi.org/10.1039/c3ra46735j SN - 2046-2069 VL - 4 IS - 13 SP - 6825 EP - 6829 PB - RSC Publishing CY - London AN - OPUS4-30287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zheng, H. A1 - Kappatos, V. A1 - Niederleithinger, Ernst A1 - Ertel, Jens-Peter A1 - Grohmann, Maria A1 - Selcuk, C. A1 - Gan, T.-H. T1 - Defect detection in concrete pile using impulse response measurements with sine sweep excitations N2 - For pile integrity inspection, a low cost and portable shaker was used to create the sine sweep signal for pile excitation. The impulse response function, calculated by the deconvolution of pile response from the sine sweep excitation, was proposed to identify the echoes in the piles due to the pile’s impedance changes. The proposed methodology has been evaluated and validated both numerically and experimentally. Based on the results from the simulations and experiments, it was found that the impulse response measurement with sine sweep excitation could be an effective tool to detect the echoes of the pile toe and the defects in the pile. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Impulse response function KW - Sine sweep excitation KW - Pile integrity KW - Damage detection PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347157 SN - 1435-4934 SP - 1 EP - 4 PB - Technische Universität Berlin / Bundesanstalt für Materialforschung und -prüfung AN - OPUS4-34715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pretsch, Thorsten T1 - Review on the functional determinants and durability of shape memory polymers N2 - Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented. KW - Shape memory polymer KW - Active polymer KW - Shape memory polymer composite KW - Shape memory properties KW - Functionality KW - Degradation KW - Aging KW - Functional determinants KW - Thermo-mechanical testing KW - Durability PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-217390 UR - http://www.mdpi.com/2073-4360/2/3/120/pdf DO - https://doi.org/10.3390/polym2030120 SN - 2073-4360 VL - 2 IS - 3 SP - 120 EP - 158 PB - MDPI CY - Basel AN - OPUS4-21739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weller, Michael G. T1 - A unifying review of bioassay-guided fractionation, effect-directed analysis and related techniques N2 - The success of modern methods in analytical chemistry sometimes obscures the problem that the ever increasing amount of analytical data does not necessarily give more insight of practical relevance. As alternative approaches, toxicity- and bioactivity-based assays can deliver valuable information about biological effects of complex materials in humans, other species or even ecosystems. However, the observed effects often cannot be clearly assigned to specific chemical compounds. In these cases, the establishment of an unambiguous cause-effect relationship is not possible. Effect-directed analysis tries to interconnect instrumental analytical techniques with a biological/biochemical entity, which identifies or isolates substances of biological relevance. Successful application has been demonstrated in many fields, either as proof-of-principle studies or even for complex samples. This review discusses the different approaches, advantages and limitations and finally shows some practical examples. The broad emergence of effect-directed analytical concepts might lead to a true paradigm shift in analytical chemistry, away from ever growing lists of chemical compounds. The connection of biological effects with the identification and quantification of molecular entities leads to relevant answers to many real life questions. KW - Toxicity KW - Drug discovery KW - Natural products KW - Environmental analysis KW - Lead identification PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-262960 DO - https://doi.org/10.3390/s120709181 SN - 1424-8220 VL - 12 IS - 7 SP - 9181 EP - 9209 PB - MDPI CY - Basel AN - OPUS4-26296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Nava, E. A1 - Tammas-Williams, S. A1 - Smith, C. A1 - Léonard, Fabien A1 - Withers, P. J. A1 - Todd, I. A1 - Goodall, R. T1 - X-ray tomography characterisation of lattice structures processed by selective electron beam melting N2 - Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 x 10⁻³ vol %) levels of pores, as do nodes at which many (in our case 24) struts meet. On the other hand, for struts more closely aligned (0° to 54°) to the build direction, the fraction of porosity appears to be much lower (~0.17 x 10⁻³%) arising mainly from pores contained within the original atomised powder particles. KW - Cellular solids KW - Aqdditive manufacturing KW - Computed tomography KW - Titanium alloys PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413689 UR - http://www.mdpi.com/2075-4701/7/8/300 DO - https://doi.org/10.3390/met7080300 SN - 2075-4701 VL - 7 IS - 8 SP - Article 300, 1 EP - 12 PB - MDPI AN - OPUS4-41368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Naresh-Kumar, G. A1 - Vilalta-Clemente, A. A1 - Jussila, H. A1 - Winkelmann, Aimo A1 - Nolze, Gert A1 - Vespucci, S. A1 - Nagarajan, S. A1 - Wilkinson, A. J. A1 - Trager-Cowan, C. T1 - Quantitative imaging of anti-phase domains by polarity sensitive orientation mapping using electron backscatter diffraction N2 - Advanced structural characterisation techniques which are rapid to use, non-destructive and structurally definitive on the nanoscale are in demand, especially for a detailed understanding of extended-defects and their influence on the properties of materials. We have applied the electron backscatter diffraction (EBSD) technique in a scanning electron microscope to non-destructively characterise and quantify antiphase domains (APDs) in GaP thin films grown on different (001)Si substrates with different offcuts. We were able to image and quantify APDs by relating the asymmetrical intensity distributions observed in the EBSD patterns acquired experimentally and comparing the same with the dynamical electron diffraction simulations. Additionally mean angular error maps were also plotted using automated cross-correlation based approaches to image APDs. Samples grown on substrates with a 4° offcut from the [110] do not show any APDs, whereas samples grown on the exactly oriented substrates contain APDs. The procedures described in our work can be adopted for characterising a wide range of other material systems possessing non-centrosymmetric point groups. KW - Polarity KW - Semiconductor KW - Antiphase boundary PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420167 SN - 2045-2322 VL - 7 SP - Article 10916, 1 EP - 10 AN - OPUS4-42016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lai Wai-Lok, Wallace A1 - Kind, Thomas A1 - Wiggenhauser, Herbert T1 - A study of concrete hydration and dielectric relaxation mechanism using ground penetrating radar and short-time fourier transform N2 - Ground penetrating radar (GPR) was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC) hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT) in joint time-frequency analysis (JTFA) domain rather than a conventional time or frequency domain alone. The signals of the direct wave traveled at the concrete surface and the reflected wave from an embedded steel bar were transformed with STFT, in which the changes of peak frequency over ages were tracked. The peak frequencies were found to increase with ages and the patterns were found to match closely with primarily the well-known OPC hydration process and secondarily, the evaporation effect. The close match is contributed to the simultaneous effects converting free to bound water over time, on both conventional OPC hydration and dielectric relaxation mechanisms. KW - Soil water content KW - Wet soil KW - Microwave KW - Moisture KW - GPR KW - Dispersion PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-239723 DO - https://doi.org/10.1155/2010/317216 SN - 1687-6172 IS - Article ID 317216 SP - 1 EP - 14 PB - Hindawi Publ. CY - New York, NY, USA AN - OPUS4-23972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert T1 - Nondestructive investigation of stress-induced damage in concrete N2 - The changes in the sonic surface wave velocity of concrete under stress were investigated in this paper. Surface wave velocities at sonic frequency range were measured on a prismatic concrete specimen undergoing several cycles of uniaxial compression. The loading was applied (or removed) gradually in predefined small steps (stress-controlled). The surface wave velocity was measured at every load step during both loading and unloading phases. Acoustic Emission (AE) test was conducted simultaneously to monitor the microcracking activities at different levels of loading. It was found that the sonic surface wave velocity is highly stress dependent and the velocity-stress relationship follows a particular trend. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories, each valid over a certain range of applied stresses. Having measured the velocities while unloading, when the material suffers no further damage, the effect of stress and damage could be differentiated. The slope of the velocity-stress curves over the elastic region was calculated for different load cycles. This quantity was normalized to yield a dimensionless nonlinear parameter. This parameter generally increases with the level of induced damage in concrete. KW - Nondestructive testing (NDT) KW - Surface wave velocity KW - Concrete KW - Acoustoelasticity KW - Microcracking PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-215943 UR - http://downloads.hindawi.com/journals/ace/2010/740189.pdf DO - https://doi.org/10.1155/2010/740189 SN - 1687-8094 SN - 1687-8086 VL - 2010 IS - Article ID 740189 SP - 1 EP - 9 PB - Hindawi Publ. Corp. CY - New York, NY, USA AN - OPUS4-21594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cervino, C. A1 - Knopp, D. A1 - Weller, Michael G. A1 - Niessner, R. T1 - Novel Aflatoxin derivatives and protein conjugates N2 - Aflatoxins, a group of structurally related mycotoxins, are well known for their toxic and carcinogenic effects in humans and animals. Aflatoxin derivatives and protein conjugates are needed for diverse analytical applications. This work describes a reliable and fast synthesis of novel aflatoxin derivatives, purification by preparative HPLC and characterisation by ESI-MS and one- and two-dimensional NMR. Novel aflatoxin bovine serum albumin conjugates were prepared and characterised by UV absorption and MALDI-MS. These aflatoxin protein conjugates are potentially interesting as immunogens for the generation of aflatoxin selective antibodies with novel specificities. KW - Aflatoxin KW - Mycotoxin KW - Hapten KW - Protein conjugation KW - Immunogen KW - Antigen KW - Antibody PY - 2007 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-147572 UR - http://www.mdpi.org/molecules/papers/12030641.pdf UR - http://www.mdpi.org/molecules/papers/12030641sm.pdf DO - https://doi.org/10.3390/12030641 SN - 1420-3049 VL - 12 IS - 3 SP - 641 EP - 653 PB - MDPI CY - Basel AN - OPUS4-14757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moreira, E.V. A1 - Rabello, J.M.B. A1 - Pereira, M.d.S. A1 - Lopes, R.T. A1 - Zscherpel, Uwe T1 - Digital radiography using digital detector arrays fulfills critical applications for offshore pipelines N2 - Digital radiography in the inspection of welded pipes to be installed under deep water offshore gas and oil pipelines, like a presalt in Brazil, in the paper has been investigated. The aim is to use digital radiography for nondestructive testing of welds as it is already in use in the medical, aerospace, security, automotive, and petrochemical sectors. Among the current options, the DDA (Digital Detector Array) is considered as one of the best solutions to replace industrial films, as well as to increase the sensitivity to reduce the inspection cycle time. This paper shows the results of this new technique, comparing it to radiography with industrial films systems. In this paper, 20 test specimens of longitudinal welded pipe joints, specially prepared with artificial defects like cracks, lack of fusion, lack of penetration, and porosities and slag inclusions with varying dimensions and in 06 different base metal wall thicknesses, were tested and a comparison of the techniques was made. These experiments verified the purposed rules for parameter definitions and selections to control the required digital radiographic image quality as described in the draft international standard ISO/DIS 10893-7. This draft is first standard establishing the parameters for digital radiography on weld seam of welded steel pipes for pressure purposes to be used on gas and oil pipelines. KW - Zerstörungsfreie Prüfung von Schweißnähten KW - Durchstrahlungsprüfung KW - Digitale Radiologie PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-225319 DO - https://doi.org/10.1155/2010/894643 SN - 1687-6172 VL - 2010 IS - Article ID 894643 SP - 1 EP - 7 PB - Hindawi Publ. CY - New York, NY, USA AN - OPUS4-22531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guitton-Spassky, Tiffany A1 - Schade, Boris A1 - Zoister, Christian A1 - Veronese, Eleonora A1 - Rosati, Marta A1 - Baldelli Bombelli, Francesca A1 - Cavallo, Gabriella A1 - Thünemann, Andreas A1 - Ghermezcheshme, Hassan A1 - Makki, Hesam A1 - Netz, Roland R. A1 - Ludwig, Kai A1 - Metrangolo, Pierangelo A1 - Singh, Abhishek Kumar A1 - Haag, Rainer T1 - Fluorinated Hexosome Carriers for Enhanced Solubility of Drugs N2 - Designing nanomaterials for drug encapsulation is a crucial, yet challenging, aspect for pharmaceutical development. An important step is synthesizing amphiphiles that form stable supramolecular systems for efficient drug loading. In the case of fluorinated drugs, these have superior properties and also a tendency toward reduced water solubility. For the first time, we report here fluorinated hexosome carriers made from nonionic dendritic amphiphiles, capable of encapsulating the fluorinated drug Leflunomide with high efficiency (62 ± 3%) and increasing its solubility by 12-fold. We synthesized amphiphiles with varying tail groups (fluorinated/alkylated), and their supramolecular self-assembly was investigated using cryogenic transmission electron microscopy and small-angle X-ray scattering. Furthermore, Leflunomide and its equivalent nonfluorinated counterpart were encapsulated within fluorinated and nonfluorinated assemblies. Self-assembly and encapsulation mechanisms were well supported by coarse-grained molecular simulations, yielding a fundamental understanding of the new systems. KW - PEFAS KW - Small-angle X-ray scattering KW - SAXS KW - Reference method PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632002 DO - https://doi.org/10.1021/jacsau.5c00198 SN - 2691-3704 VL - 5 IS - 5 SP - 2223 EP - 2236 PB - American Chemical Society (ACS) CY - Washington, DC AN - OPUS4-63200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Qiang A1 - Heuchel, Matthias A1 - Thünemann, Andreas A1 - Machatscheck, Rainhard T1 - The role of diffusion in the hydrolytic degradation of poly(lactic-co-glycolic acid): A molecular perspective N2 - This research emphasizes the importance of internal surface erosion as a key factor in the hydrolytic degradation of PLGA (poly(D,L-lactic-co-glycolic acid)) providing an alternative view of the established surface and bulk erosion degradation modes. Using molecular dynamics (MD) simulations, this study reveals the role of water and oligomer diffusion during the degradation of PLGA and highlights the importance of water channels formed as the overall water content increases. We found that these continuous water channels play a crucial role in accelerating the transport of water and the release of degradation products from the polymer matrix, as the diffusion coefficients of water and small oligomers exhibit significant differences spanning 2 to 3 orders of magnitude between the water and polymer phases. Water follows a different diffusion mechanism than polymer fragments. The diffusion rate of the fragments up to a size of octamers was found to be size-dependent and reasonably well approximated by a 1/N behavior, in line with the Rouse model. KW - Small-angle X-ray scattering KW - SAXS KW - Nanostructure KW - PLGA PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621250 DO - https://doi.org/10.1016/j.polymdegradstab.2024.111119 VL - 232 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-62125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, Alyna A1 - Holtzheimer, Lea A1 - Clarke, Coby A1 - Thünemann, Andreas A1 - Taubert, Andreas T1 - Complex Self-Organization in n-Alkylammonium Sulfobetaine Zwitterions with High Thermal Stabilities and High Expansion Coefficients N2 - Sulfobetaine zwitterions made from n-alkyl dimethylamines and butanesultone yield a series of n-alkylammonium sulfobetaine zwitterions with complex self-organization behavior. The compounds are thermally quite stable and the length of the alkyl chain directly affects all phase transition temperatures of the compounds: the longer the alkyl chain, the higher the transition temperature. All compounds exhibit lamellar order and the different phases are characterized by a lower temperature orthorhombic and a higher temperature hexagonal in-plane order. The phase transition from the orthorhombic to the hexagonal phase is always associated with an increase of the long period. The phase transition is also associated with a rather high thermal expansion coefficient. KW - SAXS KW - Small-angle X-ray scattering KW - Nanostructure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626276 DO - https://doi.org/10.1021/acs.langmuir.4c02892 SN - 1520-5827 VL - 41 SP - 4422 EP - 4434 PB - American Chemical Society (ACS) AN - OPUS4-62627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kieserling, Helena A1 - Sieg, Holger A1 - Heilscher, Jasmin A1 - Drusch, Stephan A1 - Braeuning, Albert A1 - Thünemann, Andreas A1 - Rohn, Sascha T1 - Towards Understanding Particle-Protein Complexes: Physicochemical, Structural, and Cellbiological Characterization of β-Lactoglobulin Interactions with Silica, Polylactic Acid, and Polyethylene Terephthalate Nanoparticles N2 - Nanoplastic particles and their additives are increasingly present in the food chain, interacting with biomacromolecules with not yet known consequences. A protein corona forms around the particles in these usually complex matrices, primarily with a first contact at surface-active proteins. However, systematic studies on the interactions between the particles and proteins –especially regarding protein affinity and structural changes due to surface properties like polarity – are limited. It is also unclear whether the protein corona can "mask" the particles, mimic protein properties, and induce cytotoxic effects when internalized by mammalian cells. This study aimed at investigating the physicochemical properties of model particle-protein complexes, the structural changes of adsorbed proteins, and their effects on Caco-2 cells. Whey protein β-lactoglobulin (β-Lg) was used as a well-characterized model protein and studied in a mixture with nanoparticles of varying polarity, specifically silica, polylactic acid (PLA), and polyethylene terephthalate (PET). The physicochemical analyses included measurements of the hydrodynamic diameter and the zeta potential, while the protein conformational changes were analyzed using Fourier-transform-infrared spectroscopy (FTIR) and intrinsic fluorescence. Cellular uptake in Caco-2 cells was assessed through flow cytometry, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and cellular impedance was analyzed with xCELLigence® technology. The results indicated that β-Lg had the highest affinity for hydrophilic silica particles, forming silica-β-Lg complexes and large aggregates through electrostatic interactions. The affinity decreased for PLA and was lowest for hydrophobic PET, which formed smaller complexes. Adsorption onto silica caused partial unfolding and refolding of β-Lg. The silica-β-Lg complexes were internalized by Caco-2 cells, impairing cell proliferation. In contrast, PLA- and PET-protein complexes were not internalized, though PLA complexes slightly reduced cell viability. This study enhances our understanding of protein adsorption on nanoparticles and its potential biological effects. KW - Nanoplastics KW - Microplastics KW - Reference materials KW - Scattering KW - DLS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630093 DO - https://doi.org/10.1016/j.colsurfb.2025.114702 SN - 1873-4367 VL - 253 SP - 1 EP - 12 PB - Elsevier BV CY - Amsterdam AN - OPUS4-63009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mikhlin, Yuri A1 - Muzikansky, Anya A1 - Zysler, Melina A1 - Thünemann, Andreas A1 - Zitoun, David T1 - Emerging electrochemistry of high-concentration colloids: Redox-activity, wide potential window and electrophoretic transport of iron oxide nanoparticles N2 - High-concentration, steric stabilizer free colloids and particularly their electrochemical behavior remains almost unexplored. Herein, we report on the electrochemistry (cyclic voltammetry, impedance spectroscopy, etc.) of highly concentrated aqueous colloidal dispersion up to 800 g/L of citrate-capped ∼11 nm Fe3-xO4 nanoparticles (NPs) without background electrolyte on glassy carbon electrodes. X-ray photoelectron spectroscopy was applied to analyze the reaction products. Solid-state Fe(II)/Fe(III) conversion was concluded to determine the cathodic and anodic faradaic reactions of the particles, with the currents depending on approximately square root of the concentration. The electrochemical reactions are coupled with the electrophoretic transfer of the negatively charged NPs on toward the anode, with the ohmic-type behavior in the bulk demonstrated by the nearly linear voltametric cathodic curves and frequency-independent impedance above ∼10–100 Hz. Accumulation and clogging of the NPs retards diffusion near anode. Hydrogen and especially oxygen evolution are arrested, and very large oxidation overpotentials result in extraordinary wide, up to 12 V, electrochemical window of water stability. The findings shed light onto basic features of the electrochemistry of high-concentration colloids without added electrolyte and their potential applications in redox flow batteries, electrophoretic deposition and beyond. KW - Nanoplastics KW - SAXS KW - Small-angle X-ray scattering PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644340 DO - https://doi.org/10.1016/j.jcis.2025.139247 SN - 0021-9797 VL - 703 SP - 1 EP - 18 PB - Elsevier Inc. AN - OPUS4-64434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapoor, M. A1 - Overgaard Christensen, Ch. A1 - Wittrup Schmidt, J. A1 - Dalsgaard Sørensen, J. A1 - Thöns, Sebastian T1 - Decision analytic approach for the reclassification of concrete bridges by using elastic limit information from proof loading N2 - Reclassification of bridges, i.e., a change in load rating, using reliability-based methods and a direct update with proof load information has been presented by many authors. However, bridge reclassification has hardly been studied from a decision analytic perspective, i.e., with quantification of the risks and benefits of different classification choices, and the expected benefit gain from proof loading. We derive, explain and exemplify a decision analytic approach for bridge reclassification along with models for (1) elastic and ultimate capacity and their adaptation with proof load information, (2) proof load information with classification outcomes accounting for target reliabilities and, (3) utilities including socio-economic benefits from reclassification. The approach and models are exemplified with a case study based on reclassification of bridges with a low existing classification. Decision rules, for practical use by a highway authority to find the optimal classification, are identified and documented based on: (1) the measurement of the capacity at elastic limit by proof loading, (2) the bridge reclassification benefits, and, (3) the required annual reliability level. From a Value of Information analysis, it is concluded that the proof load information is highly valuable for reclassification in cases of high socio-economic benefits and high reliability requirements. KW - Proof loading KW - Structural reliability KW - Value of information KW - Decision analysis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596845 DO - https://doi.org/10.1016/j.ress.2022.109049 SN - 0951-8320/ VL - 232 SP - 1 EP - 16 PB - Elsevier Ltd. AN - OPUS4-59684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bald, Ilko A1 - Keller, A. T1 - Molecular processes studied at a single-molecule level using DNA origami nanostructures and atomic force microscopy N2 - DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM) which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates. KW - DNA origami KW - atomic force microscopy KW - single-molecule analysis KW - DNA radiation damage KW - protein binding KW - enzyme reactions KW - G quadruplexes PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314343 DO - https://doi.org/10.3390/molecules190913803 SN - 1420-3049 VL - 19 IS - 9 SP - 13803 EP - 13823 PB - MDPI CY - Basel AN - OPUS4-31434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bender, P. A1 - Bogart, L.K. A1 - Posth, O. A1 - Szczerba, Wojciech A1 - Rogers, S.E. A1 - Castro, A. A1 - Nilsson, L. A1 - Zeng, L. J. A1 - Sugunan, A. A1 - Sommertune, J. A1 - Fornara, A. A1 - Gonzales-Alonso, D. A1 - Fernandez Barquin, L. A1 - Johansson, C. T1 - Structural and magnetic properties of multi-core nanoparticles analysed using a generalised numerical inversion method N2 - The structural and magnetic properties of magnetic multi-core particles were determined by numerical inversion of small angle scattering and isothermal magnetisation data. The investigated particles consist of iron oxide nanoparticle cores (9 nm) embedded in poly(styrene) spheres (160 nm). A thorough physical characterisation of the particles included transmission electron microscopy, X-ray diffraction and asymmetrical flow field-flow fractionation. Their structure was ultimately disclosed by an indirect Fourier transform of static light scattering, small angle X-ray scattering and small angle neutron scattering data of the colloidal dispersion. The extracted pair distance distribution functions clearly indicated that the cores were mostly accumulated in the outer surface layers of the poly(styrene) spheres. To investigate the magnetic properties, the isothermal magnetisation curves of the multi-core particles (immobilised and dispersed in water) were analysed. The study stands out by applying the same numerical approach to extract the apparent moment distributions of the particles as for the indirect Fourier transform. It could be shown that the main peak of the apparent moment distributions correlated to the expected intrinsic moment distribution of the cores. Additional peaks were observed which signaled deviations of the isothermal magnetisation behavior from the non-interacting case, indicating weak dipolar interactions. KW - Numerical inversion KW - Magnetic nanoparticles KW - Iron oxides KW - Magnetic properties KW - Structural properties PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-400952 DO - https://doi.org/10.1038/srep45990 SN - 2045-2322 VL - 7 SP - Article 45990, 1 EP - 14 AN - OPUS4-40095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agirrezabal-Telleria, Iker A1 - Guo, Y. A1 - Hemmann, Felix A1 - Arias, P. L. A1 - Kemnitz, E. T1 - Dehydration of xylose and glucose to furan derivatives using bifunctional partially hydroxylated MgF2 catalysts and N2-stripping N2 - The current furfural production yield is low due to the use of non-selective homogeneous catalysts and expensive separation. In this work, partially hydroxylated MgF2 catalysts, synthesized using different water contents, were screened during xylose dehydration in water–toluene at 160 °C. The different Lewis/Brønsted ratios on the MgF2 catalysts showed that under-coordinated Mg can isomerize xylose to xylulose, whilst the surface OH-groups were responsible for the dehydration reactions. The presence of glucose as a co-carbohydrate reduced the furfural selectivity from 86 to 81%, whilst it also led to high 5-hydroxymethylfurfural selectivity. The tests catalyzed by MgF2 in combination with simultaneous N2-stripping showed that a furfural selectivity of 87% could be achieved using low xylose loadings. Moreover, the catalysts regenerated by H2O2 showed high activity during the dehydration tests in water–toluene at 160 °C. KW - Bifunctional MgF2 KW - Lewis/Bronsted KW - Carbohydrates KW - Furan derivatives KW - N2-stripping PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-305441 DO - https://doi.org/10.1039/c4cy00129j SN - 2044-4753 SN - 2044-4761 VL - 4 IS - 5 SP - 1357 EP - 1368 PB - RSC Publ. CY - Cambridge AN - OPUS4-30544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stoch, P. A1 - Szczerba, Wojciech A1 - Bodnar, W. A1 - Ciecinska, M. A1 - Stoch, A. A1 - Burkel, E. T1 - Structural properties of iron-phosphate glasses: spectroscopic studies and ab initio simulations N2 - Vitrification is the most effective method for the immobilization of hazardous waste by incorporating toxic elements into a glass structure. Iron phosphate glasses are presently being considered as matrices for the storage of radioactive waste, even of those which cannot be vitrified using conventional borosilicate waste glass. In this study, a structural model of 60P2O5–40Fe2O3 glass is proposed. The model is based on the crystal structure of FePO4 which is composed of [FeO4][PO4] tetrahedral rings. The rings are optimized using the DFT method and the obtained theoretical FTIR and Raman spectra are being compared with their experimental counterparts. Moreover, the proposed model is in very good agreement with X-ray absorption fine structure spectroscopy (XANES/EXAFS) and Mössbauer spectroscopy measurements. According to the calculations the Fe3+ is in tetrahedral and five-fold coordination. The maximal predicted load of waste constituents into the glass without rebuilding of the structure is 30 mol%. Below this content, waste constituents balance the charge of [FeO4]- tetrahedra which leads to their strong bonding to the glass resulting in an increase of the chemical durability, transformation and melting temperatures and density. KW - Glass KW - Iron KW - DFT simulations KW - Mössbauer spectroscopy KW - XANES/EXAFS KW - FTIR spectroscopy KW - Raman spectroscopy KW - Coordination PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317351 DO - https://doi.org/10.1039/c4cp03113j SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 37 SP - 19917 EP - 19927 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Christina A1 - Zorn, R. A1 - Emmerling, Franziska A1 - Falkenhagen, Jana A1 - Frick, B. A1 - Huber, P. A1 - Schönhals, Andreas T1 - Vibrational density of states of triphenylene based discotic liquid crystals: dependence on the length of the alkyl chain N2 - The vibrational density of states of a series of homologous triphenylene-based discotic liquid crystals HATn (n = 5, 6, 8, 10, 12) depending on the length of the aliphatic side chain is investigated by means of inelastic neutron scattering. All studied materials have a plastic crystalline phase at low temperatures, followed by a hexagonally ordered liquid crystalline phase at higher temperatures and a quasi isotropic phase at the highest temperatures. The X-ray scattering pattern for the plastic crystalline phase of all materials shows a sharp Bragg reflection corresponding to the intercolumnar distance in the lower q-range and a peak at circa 17 nm-1 related to intracolumnar distances between the cores perpendicular to the columns as well as a broad amorphous halo related to the disordered structure of the methylene groups in the side chains in the higher q-range. The intercolumnar distance increases linearly with increasing chain length for the hexagonal columnar ordered liquid crystalline phase. A similar behaviour is assumed for the plastic crystalline phase. Besides n = 8 all materials under study exhibit a Boson peak. With increasing chain length, the frequency of the Boson peak decreases and its intensity increases. This can be explained by a self-organized confinement model. The peaks for n = 10, 12 are much narrower than for n = 5, 6 which might imply the transformation from a rigid system to a softer one with increasing chain length. Moreover the results can also be discussed in the framework of a transition from an uncorrelated to a correlated disorder with increasing n where n = 8 might be speculatively considered as a transitional state. KW - X-ray scattering KW - Neutron scattering KW - Differential scanning calorimetry PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304789 DO - https://doi.org/10.1039/c3cp55303e SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 16 SP - 7324 EP - 7333 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wollschläger, Nicole A1 - Tasdemir, Z. A1 - Häusler, Ines A1 - Leblebici, Y. A1 - Österle, Werner A1 - Alaca, B. E. T1 - Determination of the elastic behavior of silicon nanowires within a scanning electron microscope N2 - Three-point bending tests were performed on double-anchored, <110> silicon nanowire samples inside a scanning electron microscope (SEM) via a micromanipulator equipped with a piezo-resistive force sensor. Representing the upper and lower boundaries achievable in a consistent manner, silicon nanowires with widths of 35 nm and 74 nm and a height of 168 nm were fabricated. The nanowires were obtained monolithically along with their 10-m-tall supports through a top-down fabrication approach involving a series of etching processes. Hence, no interface compliance was introduced between supports and nanowires. Exact nanowire dimensions and cross-sectional features were determined by transmission electron microscopy (TEM) following sample preparation through focused ion beam (FIB) machining. Conducting the experiments inside an SEM chamber further raised the opportunity of the direct observation of any deviation from ideal loading conditions such as twisting, which was taken into consideration in simulations. Measured force-displacement behavior was observed to exhibit close resemblance to simulation results obtained by finite element modeling, when the bulk value of 169 GPa was taken as the modulus of elasticity for <110> silicon. Hence, test results show neither any size effect nor evidence of residual stresses for the considered nanoscale objects. The increased effect of the native oxide with reduced nanowire dimensions was captured as well. Thus this very simple in-situ testing method was found to be an alternative to elaborate AFM measurements on geometrically formidable nanostructures. The results demonstrate the applicability of the developed fabrication approach to the incorporation of silicon nanowires in functional micromechanical devices. KW - Silicon nanowire KW - Elastic behavior KW - Scanning electron microscope KW - Mechanical properties PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370383 DO - https://doi.org/10.1155/2016/4905838 VL - 2016 SP - Article 4905838, 1 EP - 6 PB - Hindawi Publishing Corporation AN - OPUS4-37038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olejko, Lydia A1 - Bald, Ilko T1 - FRET efficiency and antenna effect in multi-color DNA origami-based light harvesting systems N2 - Artificial light harvesting complexes find applications in artificial photosynthesis, photovoltaics and light harvesting chemical sensors. They are used to enhance the absorption of light of a reaction center which is often represented by a single acceptor. Here, we present different light harvesting systems on DNA origami structures and analyze systematically the light harvesting efficiency. By changing the number and arrangement of different fluorophores (FAM as donor, Cy3 as transmitter and Cy5 as acceptor molecules) the light harvesting efficiency is optimized to create a broadband absorption and to improve the antenna effect 1 (including two energy transfer steps) from 0.02 to 1.58, and the antenna effect 2 (including a single energy transfer step) from 0.04 to 8.7, i.e. the fluorescence emission of the acceptor is significantly higher when the light-harvesting antenna is excited at lower wavelength compared to direct excitation of the acceptor. The channeling of photo energy to the acceptor proceeds by Förster Resonance Energy Transfer (FRET) and we carefully analyze also the FRET efficiency of the different light harvesting systems. Accordingly, the antenna effect can be tuned by modifying the stoichiometry of donor, transmitter and acceptor dyes, whereas the FRET efficiency is mainly governed by the spectroscopic properties of dyes and their distances. KW - DNA origami KW - Light-harvesting KW - FRET KW - Antenna effect PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-405867 UR - http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra02114c#!divAbstract DO - https://doi.org/10.1039/C7RA02114C VL - 7 IS - 39 SP - 23924 EP - 23934 PB - The Royal Soc. of Chemistry AN - OPUS4-40586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Nikonov, A. Y. A1 - Dmitriev, A. I. ED - Krzanowski, J. T1 - MD sliding simulations of amorphous tribofilms consisting of either SiO2 or carbon N2 - The sliding behaviors of two simplified tribofilms with amorphous structure consisting either of SiO₂ molecules or C atoms were simulated by molecular dynamics modeling. The objective was to identify mechanisms explaining the experimentally observed lubricating properties of the two amorphous films. The impacts of layer thickness, normal pressure, temperature and different substrate materials were studied systematically, while the sliding velocity was kept constant at 30 m/s. While the layer thickness was not critical, all the other parameters showed special effects under certain conditions. Normal pressure impeded void formation and could even eliminate voids if applied at high temperature. Stick-slip sliding was changed to smooth sliding at high temperature due to void healing. Considering the carbon film, high friction forces and shearing of the entire film was observed with diamond substrates, whereas interface sliding at low friction forces and an amorphous layer of iron mixed with carbon was observed if the supporting substrates consisted of α-Fe. Both films show a decrease of friction forces and smooth sliding behavior at elevated temperature, corresponding well to the tribological behavior of and advanced nanocomposite sliding against a steel disc under severe stressing conditions when high flash temperatures can be expected. KW - dry friction KW - amorphous silica film KW - amorphous carbon film KW - sliding simulation KW - molecular dynamics PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379367 DO - https://doi.org/10.3390/lubricants4030024 VL - 4 IS - 24 PB - MDPI CY - Basel, Switzerland AN - OPUS4-37936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klykov, Oleg A1 - Weller, Michael G. T1 - Quantification of N-hydroxysuccinimide and N-hydroxysulfosuccinimide by hydrophilic interaction chromatography (HILIC) N2 - N-Hydroxysuccinimide (NHS) esters are the most important activated esters used in many different bioconjugation techniques, such as protein labelling by fluorescent dyes and enzymes, surface activation of chromatographic supports, microbeads, nanoparticles, and microarray slides, and also in the chemical synthesis of peptides. Usually, reactions with NHS esters are very reliable and of high yield, however, the compounds are sensitive to air moisture and water traces in solvents. Therefore, the quantification of NHS would be a very helpful approach to identify reagent impurities or degradation of stored NHS esters. No robust and sensitive method for the detection of NHS (or the more hydrophilic sulfo-NHS) has been reported yet. Here, a chromatographic method based on HILIC conditions and UV detection is presented, reaching a detection limit of about 1 mg L-1, which should be sensitive enough for most of the applications mentioned above. Exemplarily, the hydrolytic degradation of a biotin-NHS ester and a purity check of a fluorescent dye NHS ester are shown. An important advantage of this approach is its universality, since not the structurally variable ester compound is monitored, but the constant degradation product NHS or sulfo-NHS, which avoids the necessity to optimize the separation conditions and facilitates calibration considerably. KW - NHS KW - Sulfo-NHS KW - NHS-Ester KW - Qualitätskontrolle KW - Reinheitsbestimmung KW - HPLC PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337833 DO - https://doi.org/10.1039/c5ay00042d SN - 1759-9660 SN - 1759-9679 VL - 7 IS - 15 SP - 6443 EP - 6448 PB - RSC Publ. CY - Cambridge AN - OPUS4-33783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Carl, Peter A1 - Schneider, Rudolf T1 - Optimization and evaluation of a hapten microarray using chemometric methods N2 - The demands for the assessment of water quality are increasing steadily, making it necessary to routinely monitor multiple contaminants in water samples. For this application a hapten microarray was developed. In order to reach the required low detection limits a design of experiments (DoE) approach was used to optimize the assay performance. Here we show that a Box-Behnken design plan is an adequate choice for the straightforward exploration of hapten microarray assay parameters. For both read-out systems studied (fluorophore-labelled detection antibodies or enzymatic signal development followed by reflectometric scan, respectively), it was possible to significantly extend the measurement ranges. Furthermore, it could be shown that multivariate data analysis, here partial least squares regression (PLS), can improve the prediction accuracy of 'unknown' samples when used as calibration model, compared to classical, univariate data evaluation methods. KW - Koffein KW - Caffeine KW - Proteine microarray KW - Design of experiments KW - Multivariate data analysis KW - Partial least squares regression KW - Small molecule detection KW - Microarray KW - Immunoarray KW - Immunoassay KW - ELISA KW - Chemometrie KW - Chemometrics PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344672 DO - https://doi.org/10.1016/j.proeng.2015.08.684 SN - 1877-7058 VL - 120 SP - 501 EP - 506 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-34467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siebler, Daniel A1 - Rohwetter, Philipp A1 - Brusenbach, R. A1 - Plath, R. T1 - Optical-only detection of partial discharge with fluorescent polymer optical fiber sensors N2 - This paper reflects recent progress in the field of fluorescent polymer optical fiber sensors (F-POF) for partial discharge (PD) detection in high voltage (HV) cable accessories using optical-only PD detection by coincidence single photon counting. In experiments with artificial PD sources these sensors show the ability to detect optical emissions from picocoulomb-level PDs in a real-scale model of a translucent high voltage cable accessory. False positives (caused by detector noise) are efficiently suppressedwhile maintaining sufficient sensitivity,even when the sensor is located in an unfavorable position. T2 - EUROSENSORS 2015 CY - Freiburg, Germany DA - 06.09.2015 KW - Partial discharge KW - Silicone rubber KW - High voltage cable accessories KW - Polymer optical fiber POF KW - Fluorescence KW - Coincidence PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337881 DO - https://doi.org/10.1016/j.proeng.2015.08.711 SN - 1877-7058 VL - 120 SP - 845 EP - 848 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-33788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stengel, Dominik A1 - Mehdianpour, Milad T1 - Finite element modelling of electrical overhead line cables under turbulent wind load N2 - This paper presents a finite element model of an overhead transmission line using so called cable elements which allow reproducing the cable's nonlinear characteristics accurately employing only a few elements. Aerodynamic damping is considered in the equation of motion by taking into account the relative velocity between the flow of the wind and the moving structure. The wind flow itself is simulated by wave superposition making necessary assumptions on the lateral correlation between the wind velocities along the cable length. As result from the simulation, the following conclusions can be drawn. The first natural frequency of generally used wide spanning cables lies well below 1 Hz where also most of the energy content of the wind excitation is to be expected. Aerodynamic damping is significant for the moving cables holding very low structural damping which leads to a suppression of resonant amplification. This is particularly of interest regarding the support reaction which is dominated by the mean value and the so called background response. The latter is mostly influenced by the randomness of the wind flow, especially lateral to the main wind direction. KW - Nonlinear Finite Element Formulations KW - Nonlinear Equation of Motion KW - Turbulent Wind Excitation PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304567 DO - https://doi.org/10.1155/2014/421587 SN - 2314-6494 SN - 2356-766X VL - 2014 IS - Article ID 421587 SP - 1 EP - 8 PB - Hindawi Publ. CY - New York, NY ; Cairo AN - OPUS4-30456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maack, Stefan A1 - Kneib, G. T1 - Elastic wave propagation of ultrasound in bituminous road surfaces - simulations and measurements N2 - Maintenance costs of road infrastructure are increasing steadily. The main cause of this is the nearly exponential increase of traffic during the last decades. Adverse environmental impacts on infrastructure get more and more important as well. Therefore, it is important to determine how limited financial resources can be directed with an optimum pay-out. Often a decision has to be made whether existing structures have to be rebuilt or repaired based on the condition of the structures. The present study takes first steps towards the usage of low-frequency ultrasound as a tool to evaluate the road condition. The overall aim is to derive a prediction model for future road conditions. In order to better understand and interpret recorded wave fields simulations of elastic wave propagation in layered and scattering road models have been performed. The study combined investigations in the laboratory with field measurements. In a series of extensive laboratory tests with different asphalt mixtures characteristic wave properties have been derived. Travel time (resp. velocity) as important material parameter has been investigated for different wave types, different centre frequencies and at various temperatures. An investigation of the directivity of wave radiation in the heterogeneous asphalt bodies led to an estimate of the related disturbing influences. Based on the laboratory results field measurements were performed on a real road and the records were processed to identify layers, propagation speeds and attenuation. The results were verified by a series of simulations. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Bituminous material KW - Road inspection KW - Elastic waves KW - Ultrasound KW - Non-destructive testing PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345364 UR - https://www.ndt.net/?id=18421 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 9 PB - NDT.net CY - Kirchwald AN - OPUS4-34536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zoёga, Andreas A1 - Kurz, J. H. A1 - Oelschlägel, T. A1 - Rohrschneider, A. A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Hintze, H. A1 - Kanzler, D. T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn N2 - Currently at Deutsche Bahn (DB) ultrasonic inspections in maintenance procedures for wheelset axles with a bore hole are, to the greatest possible extent, carried out using automated ultrasonic inspection system. Although the acceptance levels are in accordance with DIN 27201 part 7, the testing results have shown in recent years that in the case of true indications, the effective defect sizes were far below the level of acceptance. Due to this experience it can be assumed that the automated ultrasonic inspection systems are testing substantially more sensitively than required. This increased sensitivity leads to an increase in false indications, generally resulting in the unnecessary demounting of wheelsets. In Research cooperation between Federal Institute for Materials Research and Testing (BAM) and DB the effective flaw detection sensitivity of existing automated ultrasonic inspection system will be determined and the true/false indication ratio optimised. Through systematic investigations with the Probability of Detection method on the existing automated ultrasonic inspection system the results could be directly applied to the optimisation of existing ultrasonic inspections of wheelset axles with a bore hole in maintenance procedures and the level of reliability can be considerably increased. T2 - 19th World Conference on Non-Destructive Testing CY - München, Germany DA - 13.06.2016 KW - NDT KW - Reliability KW - POD KW - Railway KW - Axles KW - UT PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375813 UR - http://www.ndt.net/article/wcndt2016/papers/we2g4.pdf SP - id 19515, 1 EP - 8 AN - OPUS4-37581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Müller, Alexander A1 - Hickmann, Stefan T1 - Infinite life of CFRP evaluated non-destructively with X-ray-refraction topography in-situ mechanical loading N2 - Carbon Fibre Reinforced Plastics (CFRP) are more and more used in modern civil aircrafts. These days the whole fuselage is made of this material (B787; A350). Due to strict certification standards the normal in-service loading gives a low stress level compared to the static and even the fatigue strength of the material. Hence CFRP are assumed to have an infinite life. To evaluate this assumption, fatigue tests on CFRP-specimens were performed up to 108 load cycles and the first inter-fibre failure was evaluated non-destructively by accompanying Xray-refraction topography. A tensile testing machine was integrated in a small angle X-ray scattering (SAXS) setup. X-ray refraction topography was performed while the CFRP samples were tensile loaded. This non-destructive technique enables the detection of micro-cracking and inter-fibre failure especially for CFRP. For Glass Fibre Reinforced Plastic (GFRP) X-ray refraction and in-situ loading has already been successfully used. The increase of inner surfaces due to inter fibre failure was measured as a function of the stress state. Fatigue tests were performed at and below the limit of inter-fibre failure strength. State of the art is to assume the failure of the samples under cyclic loading as the fatigue life. Accompanying non-destructive X-ray refraction measurements reflects the damage state and enables to trace its evolution even if the total failure of the specimens does not occur. This investigation technique is of high interest to give the engineer a design value of infinite life which is practically often reached due to knock down factors of certification standards. Finally the infinite life was found for cyclic fatigue loaded CFRP-samples even under high inter fibre transverse and shear loading investigated up to 108 load cycles. T2 - 19th World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - CFRP KW - NDT KW - Fatigue KW - Damage evolution PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375015 UR - https://www.ndt.net/?id=19360 SN - 978-3-940283-78-8 VL - 2016 SP - 1 EP - 9 PB - DGZFP CY - Berlin AN - OPUS4-37501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ronneteg, U. A1 - Grybäck, T. A1 - Bertovic, Marija A1 - Müller, Christina A1 - Pavlovic, Mato T1 - Safe for 1 million years – NDT matters! N2 - The General Guidance in the Swedish regulations state that the safety assessment for a final repository for spent nuclear fuel should be 1 million years after closure. SKB developed the KBS-3 method, according to which the spent nuclear fuel is protected by three barriers. It is encapsulated in canisters with a diameter of 1 metre and a length of 5 metres. The canister consists of a cast iron insert surrounded by a 5 centimetre thick shell of copper. The canisters are disposed in the bedrock at a depth of about 500 meters surrounded by bentonite clay. In order to assess the safety over this extremely long period, an extensive quality control programme is applied to the canisters before deposit. In this programme, the use of non-destructive testing (NDT) is vital. The safety assessment of the canister in turn places high demands on the coverage, detectability, and reliability of the applied NDT inspections of the canister parts, i.e. cast iron insert, copper base, tube and lid, and the copper friction stir welds (FSW). This paper presents the extensive full-scale inspection development programme that runs at the Canister Laboratory in Oskarshamn (Sweden). In order to fulfil the high demands, phased array ultrasonic inspection techniques are developed using practical trials aided by ultrasonic modelling. The techniques apply, for example, different frequencies, inspection angles, focus depths, and both longitudinal and shear waves. Increased inspection reliability of the FSW is achieved by applying digital X-ray technique using a 9 MeV linear accelerator and a line detector. To complete the coverage, complementary surface inspections methods, i.e. eddy current array, magnetic flux sensor techniques and magnetic particle inspection, are applied. The canister safety assessment was the driving force to include reliability studies during the NDT development. Initially, the technical reliability was considered, resulting in development of advanced POD models (probability of detection). In combination with human factors studies, these models were implemented as tools in the development of the NDT techniques. Human factors studies were also applied to improve the inspection procedures to be more user-friendly enabling reliable inspections. T2 - 19th World Conference on Non-Destructive Testing CY - München, Germany DA - 13.06.2016 KW - NDT KW - Reliability KW - Spent nuclear fuel PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375785 UR - http://www.ndt.net/article/wcndt2016/papers/we4e4.pdf SP - id 19464, 1 EP - 9 AN - OPUS4-37578 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüllmann, Dino A1 - Kohlhoff, Harald A1 - Neumann, Patrick P. ED - Bársony, I. ED - Zolnai, Z. ED - Battistig, G. T1 - Embedded control of a PMSM servo drive without current measurements N2 - A permanent-magnet synchronous motor (PMSM) servo drive for lightweight robotic platforms that have a high torque demand at low rotational speeds has been developed. First, a current-independent torque controller is derived and cascaded with a speed and position controller, while merely an encoder is used as a sensor device in combination with a speed estimator. Finally, the speed estimator output is compared to gyroscope measurements and the overall functioning is verified on a real system. T2 - 30th Eurosensors Conference - Eurosensors 2016 CY - Budapest, Hungary DA - 04.09.2016 KW - BLDC KW - PMSM KW - Motor control KW - Servo drive KW - Optical incremental encoder PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388973 DO - https://doi.org/10.1016/j.proeng.2016.11.487 SN - 1877-7058 VL - 168 SP - 1671 EP - 1675 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-38897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - McGrath, B. A1 - Holstein, R. A1 - Bertovic, Marija T1 - How NDT companies can benefit from human factors knowledge N2 - Ultrasonic phased array is, currently, the technology which is being applied as the solution to a lot of inspection problems. The perceived benefits are seen to be worth the outlay on equipment and specialised personnel. Yet, there is a source of knowledge, freely available, which can also deliver immediate benefits, through more reliable inspection results, and consequently increased client confidence, but which is largely ignored by the greater part of the NDT community. This talk will review the latest Human Factors knowledge and provide practical illustrations of how companies can use it to improve their competitive edge. T2 - 19th World Conference on Non-Destructive Testing CY - München, Germany DA - 13.06.2016 KW - NDT KW - Reliability KW - Human factors PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375742 UR - http://www.ndt.net/article/wcndt2016/papers/tu4d3.pdf SP - id 19532, 1 EP - 8 AN - OPUS4-37574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Eisentraut, Mark T1 - Reference block design for high resolution ultrasound immersion tank N2 - In respect of modern approaches in material sciences and highly increased requirements on materials on safety relevant components, quality management and non-destructive testing reclaims a steadily increased meaning. The destructive meaning of measuring the degree of purity is defined in DIN EN 10247 through metallurgical investigations, especially microsections. For and comparable, but non-destructive testing due ultrasonic testing, the material the SEP 1927 is a well-defined industry standard. A novel and alternative way of reference block construction was focused by this work. The proposed amendments, regarding the manufacturing and machining, are less time and cost consuming. Verified by measurements the presented reference block fits the same acoustical characteristics and the requirements of the guideline. T2 - 19th World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - SEP 1927 KW - Degree of purity KW - High resolution ultrasonic testing KW - Immersion tank testing PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-368512 VL - 2016 SP - Paper X15, 1 EP - 4 AN - OPUS4-36851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Armatys, Kamila A1 - Miller, M. T1 - Knudsen effusion mass spectrometry studies on metal halides performed in 1990-2014 N2 - Abstract Investigations on metal halide systems carried out by Knudsen effusion mass spectrometry in the period 1990-2014 are reviewed in the present paper.163 original papers were published focused on metal halides showing still considerable activity in this area. The fundamentals of the Knudsen effusion mass spectrometry method and thermodynamic background of the investigation are briefly reported. Data to the system studied, temperature ranges, Knudsen cell materials, vapor species identified in the equilibrium vapors and the thermodynamic properties obtained in the study are presented. The important issues of metal halide vaporization studies are briefly discussed and commented. The studies of the vaporization of metal halogens by Knudsen effusion mass spectrometry aimed firstly atthe determination of gaseous complexes species in the vapor and determination of its thermodynamic data like sublimation enthalpy etc. and secondly at the determination of negative ions formation and various ion-molecule equilibria reactions of metal halide systems. Many of the studied materials have a crucial role for modern technologies, for example metal halide lamps, hot corrosion caused by halide salts, phosphorus recovery technologies or gas assisted separation of lanthanides. The investigation of such systems gives information on mechanisms of vaporization, volatility of the systems under various conditions (temperature, pressure etc.), reactivity, thermal stability, resistance etc. that could be further applied for various calculations and to predict the behavior of various components under various technological aspects. KW - Metal halides KW - Knudsen Effusion Mass Spectrometry (KEMS) KW - HTMS KW - Thermochemistry KW - High temperature KW - Vaporization PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357126 SN - 2349-7092 VL - 3 IS - 1 SP - 68 EP - 93 PB - The Pharmaceutical and Chemical Journal CY - Kundlawala, India AN - OPUS4-35712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lucassen, F. A1 - Pritzkow, Wolfgang A1 - Rosner, M. A1 - Sepulveda, F. A1 - Vasquez, P. A1 - Wilke, H. A1 - Kasemann, S. A. T1 - The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile – Marine sources and diagenetic effects N2 - Seabird excrements (guano) have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy) of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic signatures towards very heavy values generate a compositionally unique material. These compositions trace the presence of guano in natural ecosystems and its use as fertilizer in present and past agriculture. KW - Isotope ratio KW - VPDB KW - Fishmeal KW - Elemental analyser KW - Vario EL III KW - Casein standard KW - ICP-OES KW - Accelerator mass spectrometry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-407911 DO - https://doi.org/10.1371/journal.pone.0179440 SN - 1932-6203 VL - 12 IS - 6 SP - Article e0179440, 1 EP - 25 PB - PLOS CY - San Francisco, California, US AN - OPUS4-40791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andres, S. A1 - Hansen, Ulf A1 - Niemann, B. A1 - Palavinskas, R. A1 - Lampen, A. T1 - Determination of the isoflavone composition and estrogenic activity of commercial dietary supplements based on soy or red clover N2 - Dietary supplements high in isolated isoflavones are commercially available for human consumption primarily to alleviate menopausal symptoms in women. The isoflavone composition, quantity and importantly their estrogenic potency are poorly standardised and can vary considerably between different products. The aim of this study was to analyse the isoflavone composition of 11 dietary supplements based on soy or red clover using the HPLC/MS/MS technique. Furthermore, we investigated the transactivational potential of the supplements on the estrogen receptors (ER), ERα and ERβ, performing luciferase reporter gene assays. As expected, we found that the isoflavone composition varies between different products. The measured total isoflavone contents in various supplements were mostly comparable to those claimed by the manufacturers in their product information. However expressing the isoflavone content as isoflavone aglycone equivalents, soy-based supplements had a clearly lower quantity compared to the manufacturer information. All supplements transactivated more or less ERα and ERβ with a preference for ERβ. The transactivational efficiency exceeded partly the maximal 17β-estradiol induced ER activation. While the different soy-based supplements revealed similar transactivation potential to both ERs, red clover-based supplements differed considerably. We conclude that different commercial dietary supplements based on soy or red clover vary in their isoflavone composition and quantity. They are estrogenically active, although especially the red clover-based supplements show considerable differences in their estrogenic potential to ERα and ERβ. Thus, different isoflavone-rich products cannot be necessarily compared regarding possible biological effects. KW - estrogenic activity KW - HPLC/MS/MS technique KW - Estrogen receptor (ER) KW - nutritional supplements PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357093 DO - https://doi.org/10.1039/C5FO00308C IS - 6 SP - 2017 EP - 2025 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-35709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Birgit Angelika A1 - Ziemann, M. A A1 - Pentzien, Simone A1 - Gabsch, T. A1 - Koch, W. A1 - Krüger, Jörg T1 - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road N2 - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified. KW - Wall paintings KW - Central Asia KW - Silk Road KW - Pigments KW - Microscopy PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357297 DO - https://doi.org/10.1179/2047058414Y.0000000152 VL - 61 IS - 2 SP - 113 EP - 122 PB - Routledge Taylor & Francis Group CY - London AN - OPUS4-35729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Franz-Georg A1 - Holm, Olaf T1 - Reduction of natural resource use by improving resource efficiency N2 - In 2011, the German Association of Engineers (VDI) started working on a set of guidelines dealing with the improvement of resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines proposals for the producing industry. A special guideline for small and medium-sized enterprises (SMEs) is included as well as guidelines on methodologies for evaluating resource use indicators, such as the cumulative raw material demand of products and production systems. The work on resource use indicators is still in progress. The evaluation of raw materials expenditure will include water, soil and land use. The model will include the availability of raw materials (criticality). Improving resource efficiency at the end-of-life stage is illustrated in this paper by the example of materials recovery from waste, here from residues out of municipal solid waste incineration (MSWI). With mechanical treatment valuable materials like ferrous and non-ferrous metals and secondary construction material can be extracted from MSWI bottom ash. The potential contribution on the resource efficiency is discussed. KW - Resource efficiency KW - Raw material equivalent KW - Mechanical treatment KW - Bottom ash KW - Waste incineration KW - Secondary raw materials KW - Product life cycle PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-356490 UR - http://www.hrpub.org/journals/jour_archive.php?id=62&iid=877 DO - https://doi.org/10.13189/ ujms.2016.040302 SN - 2331-6691 SN - 2331-6705 VL - 4 IS - 3 SP - 54 EP - 59 PB - Horizon Research Publishing CY - Alhambra, CA, USA AN - OPUS4-35649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sproesser, G. A1 - Schenker, S. A1 - Pittner, Andreas A1 - Borndörfer, R. A1 - Rethmeier, Michael A1 - Chang, Y.-J. A1 - Finkbeiner, M. T1 - Sustainable welding process selection based on weight space partitions N2 - Selecting a welding process for a given application is crucial with respect to the sustainability of part manufacturing. Unfortunately, since welding processes are evaluated by a number of criteria, preferences for one or the other process can be contradictory. However, the prevalent procedure of weight assignment for each criterion is subjective and does not provide information about the entire solution space. From the perspective of a decision maker it is important to be able to assess the entire set of possible weightings and answer the question which welding process is optimal for which set of weights. This issue is investigated by means of a weight space partitioning approach. Two welding processes are considered with respect to three criteria that reflect their economic and environmental performance. In order to find the most sustainable welding process the underlying weight space partition is evaluated. T2 - 13th Global Conference on Sustainable Manufacturing – Decoupling Growth from Resource Use CY - Bình Dương New City, Vietnam DA - 16.09.2015 KW - Welding costs KW - Multi-criteria decision support KW - LCA KW - Welding process selection KW - GMAW KW - Multi-attribute decision method PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-353740 DO - https://doi.org/10.1016/j.procir.2016.01.077 SN - 2212-8271 VL - 40 SP - 127 EP - 132 PB - Elsevier B.V. AN - OPUS4-35374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grohmann, Maria A1 - Müller, Sabine A1 - Niederleithinger, Ernst T1 - Reverse time migration: Introduction of a new imaging technique for ultrasonic measurements in civil engineering N2 - Ultrasonic echo testing is widely used in non-destructive testing in civil engineering to investigate concrete structures, to measure thickness, and to locate and characterise built-in components or inhomogeneities. Currently, synthetic aperture focusing techniques are mostly used for imaging. These algorithms are highly developed but have some limitations. For example, it is not possible to image the lower boundary of built-in components like tendon ducts or vertical reflectors. We adopted reverse time migration for non-destructive testing in civil engineering in order to improve the imaging of complicated structures in concrete. By using the entire wavefield, including waves reflected more than once, there are fewer limitations compared to synthetic aperture focusing technique algorithms. As a drawback, the required computation is significantly higher than that for the techniques currently used. Simulations for polyamide and concrete structures showed the potential for non-destructive testing. The simulations were followed by experiments at a polyamide specimen. Here, having acquired almost noise-free measurement data to test the algorithm, we were able to determine the shape and size of boreholes with sufficient accuracy. After these successful tests, we performed experiments at a reinforced concrete foundation slab. We obtained information from the data by reverse time migration, which was not accessible by traditional imaging. The imaging of the location and structure of the lower boundary of the concrete foundation slab was improved. Furthermore, vertical reflectors inside the slab were imaged clearly, and more flaws were found. It has been shown that reverse time migration is a step forward in ultrasonic testing in civil engineering. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Ultrasound KW - Imaging KW - Reverse time migration KW - Reflection seismics KW - Concrete PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345406 SN - 1435-4934 SP - 1 EP - 10 PB - Technische Universität Berlin / Bundesanstalt für Materialforschung und -prüfung AN - OPUS4-34540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Douma, J. A1 - Niederleithinger, Ernst A1 - Snieder, R. T1 - Improved focusing using deconvolution within a concrete block N2 - Time reversal techniques are used in ocean acoustics, medical imaging and non-destructive evaluation to backpropagate recorded signals to the source of origin. We demonstrate experimentally a technique which improves the temporal focus achieved at the source location. The experiment consists of propagating a signal from a transducer within a concrete block to a single receiver on the surface, and then applying time reversal or deconvolution to focus the energy back at the source location. The results show that we are able to generate a focus in time at the correct location. The proposed method is simple and proven to be robust. Additionally, its costs are negligible due to deconvolution being a preprocessing step to the recorded data. The technique can be applied for detailed investigation of the source mechanisms (e. g. cracks) but also for monitoring purposes. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Ultrasonics KW - Acoustic emission KW - Time reversal KW - Deconvolution PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337953 UR - http://www.ndt.net/article/dgzfp2014/papers/di2c2.pdf SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.2.C.2, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-33795 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuhlich, Paul A1 - Emmerling, Franziska A1 - Kraus, Werner A1 - Nehls, Irene A1 - Piechotta, Christian T1 - 1-(4-bromo-3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)ethan-1-one: a precursor for phase-I metabolite of AHTN N2 - The title compound, C18H25BrO, crystallized as a racemate with four independent molecules in the asymmetric unit. In the crystal, three of these four molecules are linked via C-Br...Br-C halogen bonds [Br...Br = 3.662 (2) and 3.652 (2) Å], forming dimers. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-279935 DO - https://doi.org/10.1107/S1600536813006934 SN - 1600-5368 VL - 69 IS - 4 SP - o545, sup-1 EP - sup-17 PB - Munksgaard CY - Copenhagen AN - OPUS4-27993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Wolf, Julia A1 - Mielentz, Frank A1 - Wiggenhauser, Herbert A1 - Pirskawetz, Stephan T1 - Embedded ultrasonic transducers for active and passive concrete monitoring N2 - Recently developed new transducers for ultrasonic transmission, which can be embedded right into concrete, are now used for non-destructive permanent monitoring of concrete. They can be installed during construction or thereafter. Large volumes of concrete can be monitored for changes of material properties by a limited number of transducers. The transducer design, the main properties as well as installation procedures are presented. It is shown that compressional waves with a central frequency of 62 kHz are mainly generated around the transducer's axis. The transducer can be used as a transmitter or receiver. Application examples demonstrate that the transducers can be used to monitor concrete conditions parameters (stress, temperature, …) as well as damages in an early state or the detection of acoustic events (e.g., crack opening). Besides application in civil engineering our setups can also be used for model studies in geosciences. KW - Ultrasound KW - Transmission KW - Concrete KW - Damages KW - Cracks KW - Stress KW - Monitoring KW - Acoustic emission KW - Transducers KW - Coda wave interferometry PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345632 DO - https://doi.org/10.3390/s150509756 SN - 1424-8220 VL - 15 IS - 5 SP - 9756 EP - 9772 PB - MDPI CY - Basel AN - OPUS4-34563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gebhardt, M.O. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Numerical analysis of hot cracking in laser-hybrid welded tubes N2 - In welding experiments conducted on heavy wall pipes, the penetration mode (full or partial penetration) occurred to be a significant factor influencing appearance of solidification cracks. To explain the observed phenomena and support further optimization of manufacturing processes, a computational model was developed, which used a sophisticated strategy to model the material. High stresses emerged in the models in regions which showed cracking during experiments. In partial penetration welding, they were caused by the prevention of weld shrinkage due to the cold and strong material below the joint. Another identified factor having an influence on high stress localization is bulging of the weld. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302961 DO - https://doi.org/10.1155/2013/520786 SN - 1687-8442 SN - 1687-8434 IS - Article ID 520786 SP - 1 EP - 8 PB - Hindawi Publishing Corporation CY - New York, NY, USA AN - OPUS4-30296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Experimental and numerical investigation of an electromagnetic weld pool control for laser beam welding N2 - The objective of this study was to investigate the influence of externally applied magnetic fields on the weld quality in laser beam welding. The optimization of the process parameters was performed using the results of computer simulations. Welding tests were performed with up to 20 kW laser beam power. It was shown that the AC magnet with 3 kW power supply allows for a prevention of the gravity drop-out for full penetration welding of 20 mm thick stainless steel plates. For partial penetration welding it was shown that an0.5 T DC magnetic field is enough for a suppression of convective flows in the weld pool. Partial penetration welding tests with 4 kW beam power showed that the application of AC magnetic fields can reduce weld porosity by a factor of 10 compared to the reference joints. The weld surface roughness was improved by 50%. KW - Laser beam welding KW - Electromagnetic weld pool support KW - Hartmann effect KW - Electromagnetic rectification PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314405 DO - https://doi.org/10.1016/j.phpro.2014.08.006 SN - 1875-3892 VL - 56 SP - 515 EP - 524 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-31440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Vivien A1 - Kusche, Nadine A1 - Kalinka, Gerhard A1 - Habel, Wolfgang T1 - Field deployable fiber bragg grating strain patch for long-term stable health monitoring applications N2 - A fiber Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications has been developed and characterized. The design concept for the patch is based on a glass-fiber reinforced plastic (gfrp) carrier material. The developed concept for the FBG integration into the carrier material was derived from reliable integration procedure of FBG sensors into composite structures. The patches' temperature sensitivity, strain gauge factor, fiber–matrix interface adhesion and fatigue behavior were characterized. As a result, FBG strain patches with linear temperature and strain behavior, as well as excellent fatigue resistance, were developed and can be used as part of a monitoring system for advanced composite materials in aerospace structures or wind turbine power plants. KW - Fiber Bragg grating KW - Patch KW - Strain gauge factor KW - Temperature sensitivity KW - Push-out test KW - Validation KW - Fatigue behavior PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-276271 DO - https://doi.org/10.3390/app3010039 SN - 2076-3417 VL - 3 IS - 1 SP - 39 EP - 54 PB - MDPI CY - Basel AN - OPUS4-27627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Niederleithinger, Ernst T1 - Innovative ultrasonic techniques for inspection and monitoring of large concrete structures N2 - Ultrasonic echo and transmission techniques are used in civil engineering on a regular basis. New sensors and data processing techniques have lead to many new applications in the structural investigation as well as quality control. But concrete structures in the nuclear sector have special features and parameters, which pose problems for the methods and instrumentation currently available, e.g. extreme thickness, dense reinforcement, steel liners or special materials. Several innovative ultrasonic techniques have been developed to deal with these issues at least partly in lab experiments and pilot studies. Modern imaging techniques as multi-offset SAFT have been used e. g. to map delaminations. Thick concrete walls have successfully been inspected, partly through a steel liner. Embedded ultrasonic sensors have been designed which will be used in monitoring networks of large concrete structures above and below ground. In addition, sensitive mathematical methods as coda wave interferometry have been successfully evaluated to detect subtle changes in material properties. Examples of measurements and data evaluation are presented. KW - Automated scanning systems KW - Multi-Offset Array KW - Enhanced Imaging KW - Embedded ultrasonic sensors PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-290513 DO - https://doi.org/10.1051/epjconf/20135604004 SN - 2100-014X VL - 56 SP - 04004-1 EP - 04004-9 PB - EDP Sciences CY - Les Ulis AN - OPUS4-29051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hansen, Ulf A1 - Thünemann, Andreas T1 - Characterization of silver nanoparticles in cell culture medium containing fetal bovine serum N2 - Nanoparticles are being increasingly used in consumer products worldwide, and their toxicological effects are currently being intensely debated. In vitro tests play a significant role in nanoparticle risk assessment, but reliable particle characterization in the cell culture medium with added fetal bovine serum (CCM) used in these tests is not available. As a step toward filling this gap, we report on silver ion release by silver nanoparticles and on changes in the particle radii and in their protein corona when incubated in CCM. Particles of a certified reference material, p1, and particles of a commercial silver nanoparticle material, p2, were investigated. The colloidal stability of p1 is provided by the surfactants polyethylene glycol-25 glyceryl trioleate and polyethylene glycol-20 sorbitan monolaurate, whereas p2 is stabilized by polyvinylpyrrolidone. Dialyses of p1 and p2 reveal that their silver ion release rates in CCM are much larger than in water. Particle characterization was performed with asymmetrical flow field-flow fractionation, small-angle X-ray scattering, dynamic light scattering, and electron microscopy. p1 and p2 have similar hydrodynamic radii of 15 and 16 nm, respectively. The silver core radii are 9.2 and 10.2 nm. Gel electrophoresis and subsequent peptide identification reveal that albumin is the main corona component of p1 and p2 after incubation in CCM that consists of Dulbecco's modified Eagle medium with 10% fetal bovine serum added. PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-335510 DO - https://doi.org/10.1021/acs.langmuir.5b00687 SN - 0743-7463 SN - 1520-5827 VL - 31 IS - 24 SP - 6842 EP - 6852 PB - American Chemical Society CY - Washington, DC AN - OPUS4-33551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neffe, A.T. A1 - Von Ruesten-Lange, M. A1 - Braune, S. A1 - Lützow, K. A1 - Roch, T. A1 - Richau, K. A1 - Krüger, A. A1 - Becherer, T. A1 - Thünemann, Andreas A1 - Jung, F. A1 - Haag, R. A1 - Lendlein, A. T1 - Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility N2 - Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo- and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials. KW - Nanotechnology KW - thrombocyte adhesion KW - biomedical applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-308196 DO - https://doi.org/10.1039/c4tb00184b SN - 2050-750X SN - 2050-7518 VL - 2 IS - 23 SP - 3626 EP - 3635 PB - Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30819 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breßler, Ingo A1 - Kohlbrecher, J. A1 - Thünemann, Andreas T1 - SASfit: a tool for small-angle scattering data analysis using a library of analytical expressions N2 - SASfit is one of the mature programs for small-angle scattering data analysis and has been available for many years. This article describes the basic data processing and analysis workflow along with recent developments in the SASfit program package (version 0.94.6). They include (i) advanced algorithms for reduction of oversampled data sets, (ii) improved confidence assessment in the optimized model parameters and (iii) a flexible plug-in system for custom user-provided models. A scattering function of a mass fractal model of branched polymers in solution is provided as an example for implementing a plug-in. The new SASfit release is available for major platforms such as Windows, Linux and MacOS. To facilitate usage, it includes comprehensive indexed documentation as well as a web-based wiki for peer collaboration and online videos demonstrating basic usage. The use of SASfit is illustrated by interpretation of the small-angle X-ray scattering curves of monomodal gold nanoparticles (NIST reference material 8011) and bimodal silica nanoparticles (EU reference material ERM-FD-102). KW - Small-angle X-ray scattering KW - Small-angle neutron scattering KW - Curve fitting KW - Nanotechnology KW - Nanoparticles KW - Polymers KW - SAXS PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343348 DO - https://doi.org/10.1107/S1600576715016544 SN - 0021-8898 SN - 1600-5767 VL - 48 SP - 1587 EP - 1598 PB - Blackwell CY - Oxford AN - OPUS4-34334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästner, Claudia A1 - Thünemann, Andreas T1 - Catalytic reduction of 4-nitrophenol using silver nanoparticles with adjustable activity N2 - We report on the development of ultra-small core-shell silver nanoparticles synthesized by an up-scaled modification of the polyol process. It is foreseen to use these thoroughly characterized particles as reference material to compare the catalytic and biological properties of functionalized silver nanoparticles. Small-angle X-ray scattering (SAXS) analysis reveal a narrow size distribution of the silver cores with a mean radius of RC = 3.0 nm and a distribution width of 0.6 nm. Dynamic light scattering (DLS) provides a hydrodynamic radius of RH = 10.0 nm and a PDI of 0.09. The particles’ surface is covered with poly(acrylic acid) (PAA) forming a shell with a thickness of 7.0 nm, which provides colloidal stability lasting for more than six months at ambient conditions. The PAA can be easily exchanged by biomolecules to modify the surface functionality. Replacements of PAA with glutathione (GSH) and bovine serum albumin (BSA) have been performed as examples. We demonstrate that the particles effectively catalyze the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. With PAA as stabilizer, the catalytic activity of 436 ± 24 L g⁻¹ s⁻¹ is the highest reported in literature for silver nanoparticles. GSH and BSA passivate the surface substantially resulting in a catalytic activity of 77.6 ± 0.9 and 3.47 ± 0.50 L g⁻¹ s⁻¹, respectively. KW - Silver nanoparticles KW - Catalysis KW - Reference material KW - Protein coating PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370655 DO - https://doi.org/10.1021/acs.langmuir.6b01477 SN - 0743-7463 SN - 1520-5827 VL - 32 IS - 29 SP - 7383 EP - 7391 AN - OPUS4-37065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breßler, Ingo A1 - Pauw, Brian Richard A1 - Thünemann, Andreas T1 - McSAS: software for the retrieval of model parameter distributions from scattering patterns N2 - A user-friendly open-source Monte Carlo regression package (McSAS) is presented, which structures the analysis of small-angle scattering (SAS) using uncorrelated shape-similar particles (or scattering contributions). The underdetermined problem is solvable, provided that sufficient external information is available. Based on this, the user picks a scatterer contribution model (or 'shape') from a comprehensive library and defines variation intervals of its model parameters. A multitude of scattering contribution models are included, including prolate and oblate nanoparticles, core-shell objects, several polymer models, and a model for densely packed spheres. Most importantly, the form-free Monte Carlo nature of McSAS means it is not necessary to provide further restrictions on the mathematical form of the parameter distribution; without prior knowledge, McSAS is able to extract complex multimodal or odd-shaped parameter distributions from SAS data. When provided with data on an absolute scale with reasonable uncertainty estimates, the software outputs model parameter distributions in absolute volume fraction, and provides the modes of the distribution (e.g. mean, variance etc.). In addition to facilitating the evaluation of (series of) SAS curves, McSAS also helps in assessing the significance of the results through the addition of uncertainty estimates to the result. The McSAS software can be integrated as part of an automated reduction and analysis procedure in laboratory instruments or at synchrotron beamlines. KW - Nanotechnology KW - Nanoparticles KW - Small-angle X-ray scattering KW - SAXS PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334396 DO - https://doi.org/10.1107/S1600576715007347 SN - 0021-8898 SN - 1600-5767 VL - 48 IS - 3 SP - 962 EP - 969 PB - Blackwell CY - Oxford AN - OPUS4-33439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szczerba, Wojciech A1 - Schott, M. A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Thermally induced structural rearrangement of the Fe(II) coordination geometry in metallo-supramolecular polyelectrolytes N2 - Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical process is generally reversible. The blue colour in the ground state is a result of a metal-to-ligand charge transfer at the Fe(II) centre ion in a quasi-octahedral geometry. When annealed at temperatures above 100 °C, the blue colour turns into green and the formerly reversible electrochromic properties are lost, even after cooling down to room temperature. The thermally induced changes in the Fe(II) coordination sphere are investigated in situ during annealing of a solid Fe-MEPE using X-ray absorption fine structure (XAFS) spectroscopy. The study reveals that the thermally induced transition is not accompanied by a redox process at the Fe(II) centre. From the detailed analysis of the XAFS spectra, the changes are attributed to structural changes in the coordination sphere of the Fe(II) site. In the low temperature state, the Fe(II) ion rests in a quasi-octahedral coordination environment surrounded by six nitrogen atoms of the pyridine rings. The axial Fe–N bond length is 1.94 Å, while the equatorial bond length amounts to 1.98 Å. In the high temperature state, the FeN6-site exhibits a distortion with the axial Fe–N bonds being shortened to 1.88 Å and the equatorial Fe–N bonds being elongated to 2.01 Å. KW - Metallo-supramolecular polyelectrolytes KW - Electrochromism KW - XANES KW - EXAFS KW - Local structure KW - Thermal stability PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317331 DO - https://doi.org/10.1039/c4cp01187b SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 36 SP - 19694 EP - 19701 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph A1 - Wiehle, Philipp T1 - Closure of "Quantification of moisture content in earth block masonry under natural climatic conditions" N2 - In January 2025, the research paper “Quantification of moisture content in earth block masonry under natural climatic conditions” was published in Construction and Building Materials. The central theme was the moisture monitoring of a masonry wall made of unstabilised earth blocks over a period of around 18 months. The experimental results were compared to WUFI simulations, and the moisture transport in layered wall constructions was eventually studied in WUFI. Prof. Janssen discussed this publication in Construction and Building Materials. He raised concerns about the experiments and modelling of moisture transport. In this closure, the capillary adsorption coefficient was recalculated, and deviations from the initial value were quantified. Sensitivity analyses were conducted in WUFI to evaluate the influence of different water vapour resistances and water adsorption coefficients. The resulting moisture transport was then compared to material moisture profiles measured using 1H NMR relaxometry. Finally, the water adsorption behaviour of different earth materials is discussed in respect to material moisture and corresponding relative humidity. KW - Earth masonry KW - Moisture transport KW - Capillary water absorption KW - Embedded humidity sensors KW - NMR KW - WUFI KW - Material moisture KW - Water vapour diffusion resistance KW - Sustainable building materials PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637569 DO - https://doi.org/10.1016/j.conbuildmat.2025.142552 SN - 0950-0618 VL - 491 SP - 1 EP - 6 PB - Elsevier Ltd. AN - OPUS4-63756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -