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 - RPRT A1 - Schaupp, Thomas A1 - Kannengießer, Thomas A1 - Burger, S. A1 - Zinke, M. A1 - Jüttner, S. T1 - Ermittlung geeigneter Wärmeführungen zur Vermeidung wasserstoffunterstützter Kaltrisse beim Schweißen höherfester Feinkornbaustähle mit modifiziertem Sprühlichtbogen N2 - Um den wachsenden Anforderungen an den stofflichen und konstruktiven Leichtbau sowie den Forderungen nach Ressourceneffizienz Rechnung zu tragen, werden in vielen Industriebranchen zunehmend höherfeste Feinkornbaustähle mit Streckgrenzen ≥ 690 MPa eingesetzt. Allerdings werden mit zunehmender Festigkeit deutlich höhere Anforderungen an deren schweißtechnische Verarbeitung gestellt. Weil gerade die Sensibilität gegenüber einer Degradation der mechanischen Eigenschaften der höherfesten Feinkornbaustähle durch den beim Schweißen aufgenommenen Wasserstoff mit steigender Festigkeit zunimmt, ist auf eine geeignete Wärmeführung zu achten. Für konventionelle MAG-Schweißprozesse liegen bereits Erfahrungen und Regelwerke zur Wärmeführung und entsprechende Wasserstoffgrenzwerte vor. Moderne Invertertechnik ermöglichte die Entwicklung modifizierter Sprühlichtbögen (mod. SLB). Im Vergleich zu konventionellen Lichtbogenprozessen wird ein äußerst kurzer und richtungsstabiler Lichtbogen, eine höhere Abschmelzleistung, ein größerer Kontaktrohrabstand und ein tieferer Einbrand realisiert. Neben den bekannten Vorteilen lassen außerdem reduzierte mögliche Nahtöffnungswinkel einen anderen Lagenaufbau und unterschiedliche Geometrien der einzelnen Schweißraupen erwarten. Jedoch fehlen hierzu Aussagen über den schweißverfahrensspezifisch eingetragenen Wasserstoff und die damit einhergehende Kaltrissgefahr. Hierzu lagen in der Industrie, besonders bei den KMU, kaum Kenntnisse vor und sollten deshalb als Ziel dieses Forschungsprojektes erarbeitet werden. Die vergleichenden Untersuchungen mit konventionellem Übergangslichtbogen und mod. SLB mit angepasster Nahtkonfiguration erfolgten an freischrumpfenden Stumpfstoßverbindungen sowohl mit Massivdraht als auch Metallpulverfülldraht. Zur Durchführung der Untersuchungen wurde eine Methodik entwickelt, die es ermöglicht, im Schweißgut realer Verbindungsschweißungen die Wasserstoffkonzentration reproduzierbar zu bestimmen. Anhand der Analysen konnte gezeigt werden, dass die Schweißprozessparameter die in das Schweißgut eingebrachte Wasserstoffkonzentration in Einlagenschweißungen beeinflussen. Auch beim Mehrlagenschweißen gestaltet sich der Wasserstoffeintrag abhängig von den Schweißprozessparametern und ist auf den unterschiedlichen Lagenaufbau zurückzuführen. Grundsätzlich ist den erarbeiteten Ergebnissen zu entnehmen, dass im Schweißgut von Stumpfstoßverbindungen mit abgesenktem Nahtöffnungswinkel erhöhte mittlere Wasserstoffkonzentrationen existieren. Außerdem beinhalten Schweißgüter aus Metallpulverfülldraht höhere Wasserstoffmengen als Massivdrahtschweißungen. Geeignete Wärmeführungen führten zu einer signifikanten Reduzierung der Wasserstoffkonzentration bei dem Einsatz der Nahtkonfiguration mit abgesenktem Nahtöffnungswinkel. Dabei erwies sich eine Nachwärmprozedur aus der Schweißwärme heraus als zielführend. Die Vorstellung von Zwischenergebnissen in Normungsgremien erfolgten, um mittelfristig vor allem den KMU eine sichere Verarbeitung höherfester Feinkornbaustähle zu ermöglichen. Die dargestellten Ergebnisse stellen einen wichtigen Beitrag zur sicheren Auslegung von Schweißkonstruktionen aus höherfestem Feinkornbaustahl dar und ermöglichen den KMU die technischen und wirtschaftlichen Vorteile der mod. SLB-Prozesse auszunutzen sowie unter Berücksichtigung der wasserstoffunterstützten Kaltrissbildung kostenintensive Nacharbeiten zu reduzieren. KW - Wasserstoff KW - MAG-Schweißen KW - Höherfester Feinkornbaustahl KW - Schweißprozessparameter KW - Wärmeführung KW - Kaltrissprüfung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425946 SP - 1 EP - 94 AN - OPUS4-42594 LA - deu 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 - CONF A1 - Mähner, D. A1 - Sodeikat, Ch. A1 - Maack, Stefan T1 - ZfPBau-Verfahren an Elementwänden – Fallbeispiele und vergleichende Untersuchungen N2 - Die zerstörungsfreien Prüfverfahren konnten ihre Fähigkeit bei der Untersuchung von Elementwänden in einzelnen Fallstudien erbringen. Aufbauend auf den Kenntnissen aus der Praxis und auf Testreihen im Rahmen von Laboruntersuchungen wurde ein erster Ringversuch geplant und durchgeführt. Im Rahmen dieses Ringversuchs wurden verschiedene Strukturdefekte und Einbauteile in Elementwände eingebaut. Die Messung der Wände erfolgte anschließend durch mehrere Messteams mit unterschiedlichen zerstörungsfreien Prüfverfahren. Zum Einsatz kamen hierbei das Ultraschall-Echo- und das Impact-Echo-Verfahren sowie das Impuls-Radar-Verfahren. Zur Verbesserung der Vergleichbarkeit zwischen den unterschiedlichen Prüfverfahren wurde auf die Elementwände ein einheitliches Messraster aufgebracht. Für eine möglichst objektive Messung der Wände erhielten die Messteams vor den Messungen keine Details zu den Strukturdefekten oder Einbauteilen. Die Prüfaufgabe bestand darin, die Wände mit dem jeweiligen Prüfverfahren zu untersuchen. Anschließend wurden die Ergebnisse der Messteams zentral gesammelt und ausgewertet. Anhand der zentralen Auswertung sollten Aussagen zu den eingebauten Inhomogenitäten ableitet werden. Hierdurch kann zum einen die Leistungsfähigkeit der Prüfverfahren an unterschiedlichsten Inhomogenitäten getestet werden, zum anderen können die Ergebnisse und somit die Prüfverfahren untereinander verglichen werden. Zu diesen in der Praxis immer häufiger vorkommenden Fragestellungen können grundsätzliche Aussagen zum Einsatz von zerstörungsfreien Prüfungen bei Elementwänden gewonnen werden. Über die Ergebnisse dieses Ringversuches wird nachfolgend berichtet. T2 - Fachtagung Bauwerksdiagnose - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Germany DA - 25.02.2016 KW - Beton KW - Zerstörungsfreie Prüfung im Bauwesen KW - Elementwände KW - WU-Bauwerke PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388331 UR - http://www.bauwerksdiagnose2016.de/Portals/bwd2016/BB/vortrag%2010.pdf SP - 1 EP - 22 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. CY - Berlin AN - OPUS4-38833 LA - deu 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 - CONF A1 - Maack, Stefan A1 - Holst, R. T1 - Rekonstruktion des Bestandsplans im Zuge der Nachrechnung der Brücke über die Leine bei Schwarmstedt N2 - Der aktuell im Rahmen der Nachrechnungsrichtlinie geforderte Nachweis von Tragfähigkeit, Gebrauchstauglichkeit und Ermüdung der Brückenbauwerke im Bestand der Länder und des Bundes stellt eine enorme Herausforderung dar. Insbesondere bei unvollständigen oder fehlenden Bestandsplänen der Bauwerke sind Maßnahmen erforderlich, um die erforderlichen Informationen zu beschaffen. Ein wirkungsvolles Instrument können hierfür die zerstörungsfreien Prüfverfahren des Bauwesens sein. In dem präsentierten Forschungsprojekt erfolgte die Rekonstruktion eines Bestandsplanes direkt auf die Anforderungen des mit der Nachrechnung beauftragten Ingenieurbüros. Darüber hinaus wurde der Entwurf eines Leitfadens erstellt, der im Falle von unvollständigen oder fehlenden Bestandsplänen die Grundlagen für die Beauftragung und Durchführung der Nachrechnung schafft. T2 - Fachtagung Bauwerksdiagnose 2016 - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Germany DA - 25.02.2016 KW - Zerstörungsfreie Prüfung KW - Nachrechnungsrichtlinie KW - Brücken PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388355 UR - http://www.bauwerksdiagnose2016.de/Portals/bwd2016/BB/vortrag%206.pdf SP - 1 EP - 14 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. CY - Berlin AN - OPUS4-38835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pirskawetz, Stephan A1 - Hüsken, Götz A1 - Gründer, Klaus-Peter A1 - Kadoke, Daniel ED - Bohse, Jürgen ED - Purschke, Matthias T1 - Analyse der Schadensmechanismen biegebeanspruchter Stahlbetonbalken mittels zerstörungsfreier Prüftechniken N2 - Der durch Kräfte senkrecht zur Stabachse belastete Balken ist eines der Haupttragelemente des Stahlbetonbaus. Biegebalken finden unter anderem Anwendung in Form von Brückenträgern oder Unterzügen. Die bei maximaler Beanspruchung auftretenden Versagensformen unterteilen sich dabei in Biege- und Querkraftversagen (Schubversagen). Ein Versagen des Balkens kann je nach Versagensmechanismus mit oder ohne Vorankündigung erfolgen. Gebräuchliche Bemessungskonzepte der Baupraxis zur Dimensionierung entsprechender Tragelemente zielen auf ein Versagen mit ausreichender Vorankündigung (große Verformungen oder breite Risse) ab, wie es z.B. beim sekundären Biegedruckversagen entsteht. Für die Zustandsüberwachung von Bauwerken (z.B. Brücken) mittels zerstörungsfreier Prüftechniken sind fundierte Kenntnisse zu den bei Biegebeanspruchung auftretenden Schadensmechanismen erforderlich. Im Rahmen eines BAM-internen Projektes sollen durch praxisnahe Untersuchungen an einer brückenähnlichen Referenzstruktur unterschiedliche auf das Tragwerk einwirkende thermische und mechanische Belastungen untersucht werden und in die Entwicklung eines Monitoringsystems einfließen. Anhand der aus Biegeversuchen vorliegenden Ergebnisse wird der Einsatz unterschiedlicher Methoden der zerstörungsfreien Materialprüfung gezeigt und deren Anwendbarkeit für die Analyse des Verformungsverhaltens von Stahlbetonbalken diskutiert. Hierzu wurde das Verformungsverhalten eines Stahlbetonbalkens (L = 2,75 m) in einem Vierpunkt-Biegeversuch im Labormaßstab untersucht. Das Hauptaugenmerk liegt dabei auf der Charakterisierung der ausschlaggebenden Versagensmodi durch die einzelnen zerstörungsfreien Prüfverfahren und der Vergleich zu klassischen Messmethoden (z.B. Verformungsmessung mittels induktiver Wegaufnehmer (IWA)). Die Biegeversuche wurden dazu durch Schallemissionsanalyse (SEA) und optische Verformungsanalyse mittels Stereo-Fotogrammetrie (SF) und Bildkorrelationsverfahren (BKV) begleitet. T2 - 21. Kolloquium Schallemission CY - Fulda, Germany DA - 09.03.2017 KW - Optische Verformungsanalyse KW - Rissbildung KW - Schallemission KW - Stahlbeton KW - Tragverhalten bei Biegebeanspruchung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393617 SN - 978-3-940283-82-5 VL - 59 SP - 1 EP - 10 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-39361 LA - deu 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 - Spranger, Holger A1 - Beckmann, Jörg T1 - THz-SAFT Rekonstruktion von HDPE-Bauteilen N2 - Obwohl THz-TDS-Systeme vielfältige Qualitätsparameter von Dielektrika ermitteln können, ist deren industrielle Nutzung im Bereich der zerstörungsfreien Bauteilprüfung noch nicht anerkannter Stand der Technik. Ein pragmatischer Weg, TDS-Systeme neben traditionellen Prüfverfahren zu etablieren, sind systematische Untersuchungen an Modellbauteilen, mit dem Ziel einer Methodenentwicklung zur zuverlässigen berührungslosen Prüfung von Dielektrika. Anhand von THz-TDS-Messungen an Polyethylen-Testkörpern mit künstlich eingebauten Fehlstellen werden anfänglich die Möglichkeiten der Laufzeitmessung zur Ermittlung von Tiefenlagen von Ungänzen in Testkörpern präsentiert. Im weitern Teil wird gezeigt, wie durch eine veränderte Versuchsdurchführung und Verwendung eines modifizierten SAFT-Rekonstruktions-Algorithmus Tomogramme berechnet werden können, in denen die künstlich eingebrachten Fehlstellen hinsichtlich ihrer Größe und Lage geometrisch richtig dargestellt werden. T2 - 3. Fachseminar des FA MTHz Mikrowellen- und Terahertz-Prüftechnik in der Praxis CY - Würzburg, Germany DA - 05.04.2017 KW - THz KW - THz-SAFT KW - THz-TDS KW - SAFT KW - HDPE PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396883 SN - 978-3-940283-84-9 VL - 161 SP - 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-39688 LA - deu 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 - Kanzler, D. A1 - Pavlovic, Mato A1 - Bertovic, Marija T1 - Zukünftige Möglichkeiten und Pflichten der zerstörungsfreien Prüfung N2 - In unserer heutigen Zeit werden die Zwischenräume innerhalb der einzelnen Abteilungen eines Betriebs und zwischen einzelnen nationalen oder globalen Akteuren immer wichtiger: Produzierbarkeit vs. Wirtschaftlichkeit, Fortschritt vs. Nachhaltigkeit. Auch die zerstörungsfreie Prüfung (ZfP) – bisher hauptsächlich als Endkontrolle oder Wartungselement wahrgenommen – kann und sollte im Wandel der Digitalisierung und Industrie 4.0 einen neuen Stellenwert erhalten. Die ZfP kann schon während der Konstruktion helfen, sichere und zuverlässige Produkte zu erstellen. Jedoch müssen dafür eine adäquate Informationskultur und die notwendigen Kennzahlen vorhanden sein. Objektive, probabilistische Kennzahlen (wie die POD - Auffindwahrscheinlichkeit) sind hierbei der Schlüssel. Diese müssen jedoch unbedingt an Prüfverfahren, Prüfgegenstand und Prüfbedingung angepasst werden, da sonst die gesamte Aussage in Frage zu stellen ist. Im Vortrag werden Beispiele aus der Anwendung gezeigt, die die Aussagekraft der Kennzahl aber auch die Sorgfalt, mit denen die einzelnen Aussagen genutzt werden, unterstrichen werden soll. Bewertung von Daten von realen Fehler, Anpassung an die Bruchfestigkeit und die Betrachtung von mehreren Prüfparametern am Beispiel der Bewertung von radiographischen, Ultraschall- und Wirbelstromprüfung werden in dem Vortrag gezeigt. T2 - DGZfP-Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Zuverlässigkeit KW - Zerstörungsfreie Prüfung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404877 SN - 978-3-940283-85-6 VL - DGZfP-Berichtsband BB 162 SP - 1 EP - 6 AN - OPUS4-40487 LA - deu 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 - CONF A1 - Müller, Sabine A1 - Niederleithinger, Ernst T1 - Anwendung der Reverse Time Migration auf Ultraschall-Echo-Messungen in der zerstörungsfreien Prüfung im Bauwesen N2 - Ultraschall-Echo-Messungen dienen im Bauwesen zur Dickenbestimmung von Bauteilen sowie der Lokalisierung und Charakterisierung von Einbauteilen, Einlagerungen und anderen Inhomogenitäten. Zur Rekonstruktion werden bisher Abbildungsverfahren wie z.B. 3D-SAFT genutzt. Diese setzen aber voraus, dass direkte Reflexionen am Abbildungsobjekt erfolgen. Deshalb können keine zuverlässigen Aussagen über den Durchmesser von eingebauten Spannkanälen oder z. B. Seitenkanten von Objekten getroffen werden. Ziel laufender Forschungsarbeiten ist es, die Abbildungsqualität zu verbessern. Mit der aus der Geophysik stammenden Reverse Time Migration, die bereits häufig in der Erdölexploration genutzt wird, lassen sich auch steilere Strukturen über 70° abbilden und somit auch die Unterseite von Einbauten oder Stufen in Bauteilen darstellen. Um die Leistungsfähigkeit des Algorithmus für die zerstörungsfreie Prüfung zu untersuchen, wurden verschiedene Simulationsrechnungen durchgeführt. Dabei wurden typische Prüfprobleme unterschiedlicher Komplexität zunächst in Polyamid nachgestellt. Die Schwerpunkte lagen bei der Darstellung senkrechter Grenzflächen und Hohlstellen. Die Rechnungen dienten neben der Evaluierung und Optimierung des Verfahrens auch der Planung von Experimenten an Probekörpern mit verschiedenen Einbauten. Die Simulationsergebnisse wurden an einem dem synthetischen Modell entsprechenden Polyamidprobekörper überprüft, an dem rauscharme Ultraschalldaten aufgenommen werden konnten. In einer Messreihe wurde in den Probekörper eine Bohrung eingebracht und schrittweise vergrößert. Mit diesen Messungen konnte die Leistungsfähigkeit der Reverse Time Migration auch an realen Ultraschalldaten nachgewiesen werden. Untersuchungen mit an Beton aufgenommenen Ultraschalldaten werden folgen. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Ultraschall KW - Reverse Time Migration KW - Zerstörungsfreie Prüfung PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-319311 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1.C.4, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-31931 LA - deu 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 - TY - JOUR A1 - Wolf, S. A1 - McMahon, Dino Peter A1 - Lim, K.S. A1 - Pull, C.D. A1 - Clark, S.J. A1 - Paxton, R.J. A1 - Osborne, J.L. T1 - So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees N2 - Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed. PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-328827 DO - https://doi.org/10.1371/journal.pone.0103989 SN - 1932-6203 VL - 9 IS - 8 SP - e103989, 1 EP - 15 PB - PubMed Central AN - OPUS4-32882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mirtschin, Nikolaus A1 - Pretsch, Thorsten T1 - Designing temperature-memory effects in semicrystalline polyurethane N2 - Temperature-memory polymers are able to generate a substantial mechanical response when heated above the temperature, at which a preceding deformation was carried out. Here we show how to design the temperature-memory effect (TME) by thermomechanical treatment. As a model polymer, phase segregated poly(ester urethane) (PEU) containing crystallizable segments of poly(1,4-butylene adipate) (PBA) was used. For programming, strain elongation was applied at temperatures within the PBA melting transition area, before temperature holding, unloading and cooling were carried out. Upon heating under stress-free or constant strain recovery conditions, precisely set temperature-memory onsets could be witnessed. Most importantly, strain fixities and recoverabilities the same as maximum recovery stresses turned out to be controllable by strain rate and temperature holding time after deformation, while transition temperatures remained largely unaffected. The tailoring of thermoresponsiveness was structurally enabled by different PBA crystallinities in the programmed state as verified by wide-angle X-ray scattering (WAXS). The reported studies intend to design TMEs in semicrystalline polyurethanes according to user-defined needs to make this technology broadly applicable. KW - Poly(ester urethane) KW - Shape memory polymer KW - Temperature-memory effect KW - Thermo-responsiveness KW - Temperature-memory polymer KW - Programming KW - Thermomechanical properties PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332856 DO - https://doi.org/10.1039/c5ra05492c SN - 2046-2069 VL - 5 IS - 57 SP - 46307 EP - 46315 PB - RSC Publishing CY - London AN - OPUS4-33285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ehlert, Christopher A1 - Unger, Wolfgang A1 - Saalfrank, P. T1 - C K-edge NEXAFS spectra of graphene with physical and chemical defects: a study based on density functional theory N2 - Recently, C K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of graphite (HOPG) surfaces have been measured for the pristine material, and for HOPG treated with either bromine or krypton plasmas (Lippitz et al., Surf. Sci., 2013, 611, L1). Changes of the NEXAFS spectra characteristic for physical (krypton) and/or chemical/physical modifications of the surface (bromine) upon plasma treatment were observed. Their molecular origin, however, remained elusive. In this work we study by density functional theory, the effects of selected point and line defects as well as chemical modifications on NEXAFS carbon K-edge spectra of single graphene layers. For Br-treated surfaces, also Br 3d X-ray Photoelectron Spectra (XPS) are simulated by a cluster approach, to identify possible chemical modifications. We observe that some of the defects related to plasma treatment lead to characteristic changes of NEXAFS spectra, similar to those in experiment. Theory provides possible microscopic origins for these changes. KW - Graphene KW - NEXAFS KW - Spectrum simulation KW - Density functional theory PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309658 DO - https://doi.org/10.1039/c4cp01106f SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 27 SP - 14083 EP - 14095 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cordeiro, F. A1 - Llorente-Mirandes, T. A1 - López-Sánchez, J.F. A1 - Rubio, R. A1 - Sánchez-Agullo, A. A1 - Raber, G. A1 - Scharf, Holger A1 - Vélez, D. A1 - Devesa, V. A1 - Fiamegos, Y. A1 - Emteborg, H. A1 - Seghers, J. A1 - Robouch, P. A1 - De la Calle, M.B. T1 - Determination of total cadmium, lead, arsenic, mercury and inorganic arsenic in mushrooms: outcome of IMEP-116 and IMEP-39 N2 - The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate General of the European Commission, operates the International Measurement Evaluation Program (IMEP). IMEP organises inter-laboratory comparisons in support of European Union policies. This paper presents the results of two proficiency tests (PTs): IMEP-116 and IMEP-39, organised for the determination of total Cd, Pb, As, Hg and inorganic As (iAs) in mushrooms. Participation in IMEP-116 was restricted to National Reference Laboratories (NRLs) officially appointed by national authorities in European Union member states. IMEP-39 was open to all other laboratories wishing to participate. Thirty-seven participants from 25 countries reported results in IMEP-116, and 62 laboratories from 36 countries reported for the IMEP-39 study. Both PTs were organised in support to Regulation (EC) No. 1881/2006, which sets the maximum levels for certain contaminants in food. The test item used in both PTs was a blend of mushrooms of the variety shiitake (Lentinula edodes). Five laboratories, with demonstrated measurement capability in the field, provided results to establish the assigned values (Xref). The standard uncertainties associated to the assigned values (uref) were calculated by combining the uncertainty of the characterisation (uchar) with a contribution for homogeneity (ubb) and for stability (ust), whilst uchar was calculated following ISO 13528. Laboratory results were rated with z- and zeta (ζ)-scores in accordance with ISO 13528. The standard deviation for proficiency assessment, σp, ranged from 10% to 20% depending on the analyte. The percentage of satisfactory z-scores ranged from 81% (iAs) to 97% (total Cd) in IMEP-116 and from 64% (iAs) to 84% (total Hg) in IMEP-39. KW - Inorganic arsenic KW - Trace elements KW - Mushrooms KW - Proficiency test PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-326092 DO - https://doi.org/10.1080/19440049.2014.966336 SN - 1944-0057 SN - 1944-0049 VL - 32 IS - 1 SP - 54 EP - 67 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-32609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, Felix A1 - Jäger, Christian A1 - Kemnitz, E. T1 - Comparison of acidic site quantification methods for a series of nanoscopic aluminium hydroxide fluorides N2 - Quantitative determination of acidic surface sites is highly important for the characterization of solid acids because the activity of a catalyst is often related to the concentration of these sites. A recently developed method using 15N Nuclear Magnetic Resonance spectroscopy (NMR) for the quantification of acidic Lewis and Brønsted sites has been tested for a series of nanoscopic aluminum hydroxide fluorides. Comparison with other methods for the quantitative determination of acidic sites shows that this 15N NMR quantification method is a promising technique for the comprehensive investigation of acidic sites. Three different acidic sites, one Brønsted and two Lewis sites, can be distinguished by their 15N chemical shifts of pyridine and simultaneously quantified under conditions corresponding to catalytic reaction conditions. Determination of the individual concentrations of acidic sites allows further insight into the catalytic process. It was found that the concentration of Brønsted sites correlates with catalyzed conversion of citronellal to isopulegol in the investigated series of catalysts. Additionally, investigations indicate that one of the Lewis sites become blocked during the reaction of citronellal. KW - Solid acids KW - TOF KW - NH3-TPD KW - Progressive catalyst poisoning KW - FTIR KW - Quantitative NMR KW - Solid state NMR PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323280 DO - https://doi.org/10.1039/c4ra09477h SN - 2046-2069 VL - 4 IS - 100 SP - 56900 EP - 56909 PB - RSC Publishing CY - London AN - OPUS4-32328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Naus, D.J. T1 - NDE of thick and highly reinforced concrete structures: state of the art N2 - The objective of the report is to present the state-of-the art of non-destructive testing methods and technologies for the inspection of thick, heavily-reinforced structures, (e.g. found in nuclear power plants). Wall thicknesses can be in excess of one meter and the structures often have increased steel reinforcement density. The accessibility for any testing method may be limited due to the presence of liners and other components such as cast-in-place items. Testing methods have to provide solutions for tasks such as locating failure (inclusions, corrosion, voids, delaminations) in the structures or the assessment of the condition of the structure in general. KW - Non-destructuive testing KW - Inspection KW - Nuclear power plant KW - State-of-the-art KW - Highly reinforced concrete KW - NDE KW - Engineering PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-329674 DO - https://doi.org/10.1016/j.proeng.2014.11.055 SN - 1877-7058 VL - 86 SP - 420 EP - 426 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-32967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ressnig, A. A1 - Corbiere, T. A1 - Lunkenbein, T. A1 - Braun, Ulrike A1 - Willinger, M. G. A1 - Antonietti, M. T1 - Decomposition synthesis of tuneable, macroporous carbon foams from crystalline precursors via in situ templating N2 - A flexible, sustainable, one-step thermal decomposition route for the synthesis of hierarchical, heteroatom doped carbon foams is presented. Task-specific semi-organic crystals combine functions for three different purposes: the carbon and heteroatom source, a foaming agent (CO2) and an in situ generable template (NaCl). Insights to the decomposition pathway were gained through FTIR/MS coupled TGA and an ultrafast out-of-furnace heating procedure and the products were analysed with (HR)SEM/TEM, EELS, FTIR, and N2 sorption. The resulting macroporous carbon foams are excellent supports for metallic nanoparticles due to their hierarchical structure, high surface area and tuneable heteroatom contents. This was demonstrated for catalytically active copper or the magnetic CoNi alloy for water purification. KW - macroporous carbon KW - thermal decomposition KW - synthesize heteroatom KW - in situ template (NaCl) PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-318641 DO - https://doi.org/10.1039/c4ta03646h SN - 2050-7496 SN - 2050-7488 VL - 2 IS - 42 SP - 18076 EP - 18081 PB - RSC CY - London [u.a.] AN - OPUS4-31864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosemann, Paul A1 - Müller, C. A1 - Baumann, O. A1 - Modersohn, W. A1 - Halle, T. T1 - Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062 N2 - The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments. T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 16.03.2017 KW - Corrosion resistance KW - Welding KW - Duplex stainless steels KW - Pitting corrosion KW - Surface treatment PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395374 DO - https://doi.org/10.1088/1757-899X/181/1/012019 SN - 1757-899X SN - 1757-8981 VL - 181 IS - Conference 1 SP - Article UNSP 012019, 1 EP - 9 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ecker, Melanie A1 - Pretsch, Thorsten T1 - Novel design approaches for multifunctional information carriers N2 - Two design approaches for multifunctional information carriers are introduced. In the first one, quick response (QR) code carriers, which were composed of poly(ester urethane) (PEU) and microencapsulated thermochromic pigments (T-PIGs), differing in color and color switching temperature (CST), were prepared. The obtained material systems exhibited machine-readable QR codes at 23 °C and a two-stage decolorization when heated, culminating in unreadable QR codes at temperatures above the highest CST of the employed T-PIGs. In the second scenario, information carriers were sealed with a dark, thermochromic PEU layer. As a result, the QR codes were hidden at 23 °C and became readable upon heating due to color fading. Beyond the characterization of the employed components, preparation methods, functionality analyses and durability investigations are reported. When heated after thermo-mechanical programming, pronounced shape memory properties could be verified. The thermo-responsiveness of such multifunctional material systems may qualify them for usage in anti-counterfeiting applications. KW - Poly(ester urethane) KW - Shape memory polymer KW - Thermo-responsiveness KW - Information carrier KW - QR code carrier KW - Thermochromic properties KW - Microencapsulated thermochromic pigments KW - Anti-counterfeiting KW - Smart label KW - Difficult-to-copy KW - Durability KW - Multifuncitonal material systems PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-315176 DO - https://doi.org/10.1039/c4ra08977d SN - 2046-2069 VL - 4 IS - 87 SP - 46680 EP - 46688 PB - RSC Publishing CY - London AN - OPUS4-31517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Buckle, T. A1 - van der Wal, S. A1 - van Malderen, S. A1 - Müller, Larissa A1 - Kuil, J. A1 - van Unen, V. A1 - Peters, R. A1 - van Bemmel, M. A1 - McDonnell, L. A1 - Velders, A. A1 - Koning, F. A1 - Vanhaeke, F. A1 - van Leeuwen, F. T1 - Hybrid imaging labels: providing the link between mass spectrometry-based molecular pathology and theranostics N2 - Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for in vitro and in vivo evaluation; e.g. fluorescence or nuclear medicine. In this study a bimodal (or rather, hybrid) tracer that contains both a fluorescent dye and a chelate was used to evaluate the existence of a direct link between mass spectrometry (MS) and in vitro and in vivo molecular imaging findings using fluorescence and radioisotopes. At the same time, the hybrid label was used to determine whether the use of a single isotope label would allow for MS-based diagnostics. KW - Imaging KW - Laser Ablation ICP-MS KW - Diagnostics PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396813 DO - https://doi.org/10.7150/thno.17484 VL - 7 IS - 3 SP - 624 EP - 633 PB - IvySpring AN - OPUS4-39681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Grothausmann, R. A1 - Manke, I. T1 - Verbesserte Elektronen-Tomographie mittels DIRECTT-Algorithmus N2 - Tomographische Messungen in Transmissions-Elektronenmikroskopen beziehen ihren Reiz aus der hohen Ortsauflösung im Nanometerbereich. Allerdings bringen sie neben dem hohen Aufwand bei der Probenpräparation auch eine außerordentliche Häufung von Restriktionen der Messung mit sich, die bei Verwendung herkömmlicher Rekonstruktionsalgorithmen zu erheblichen Artefakten führen. Diese Restriktionen betreffen: partielle Nichtdurchstrahlbarkeit, einen eingeschränkten Winkelbereich, wenige Projektionen in Bezug auf die Detektorgröße, Probenabbildungen größer als der Detektor, instabile Rotationsachse, variierende Winkelinkremente sowie Probenveränderungen während der Messung. Der DIRECTT-Algorithmus (Direkte iterative Rekonstruktion computertomographischer Trajektorien) kann, abgesehen von der Probenveränderung, sämtliche dieser Restriktionen geeignet berücksichtigen. Die auftretenden, teils unvollständigen Bahnen lassen sich mittels einer Treffertabelle und geeigneter Auswahl iterativ behandeln. Außerdem kann das Rekonstruktionsvolumen über die Detektorlänge hinaus erweitert werden. Damit gelingt eine weitgehende Unterdrückung von Rekonstruktionsartefakten, insbesondere der sonst dominanten Streifenartefakte, und eine deutliche Erhöhung der Ortsauflösung. Die Verbesserung der Rekonstruktionsqualität wird anhand von Modell- und experimentellen Daten gezeigt. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Germany DA - 30.05.2011 KW - Elektronen-Tomographie KW - Computer-Tomographie KW - Rekonstruktionsalgorithmen PY - 2011 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (P8) SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-25004 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unnikrishnakurup, Sreedhar A1 - Myrach, Philipp A1 - Polomski, Benjamin A1 - Le Claire, Elisabeth A1 - Vengara, N. A1 - Balasubramaniam, Krishnan A1 - Ziegler, Mathias T1 - Thermographic crack detection in hot steel surfaces N2 - The detection and characterization of surface cracks in steel specimens prior to damage is a technologically and economically highly significant task and is of utmost importance when it comes to safety-relevant structures. In steel production where steel billets at high temperatures have to be inspected while moving a number of well-established NDT methods cannot be applied. Laser thermography however is a promising candidate to serve as a fast, non-contact and remote tool in this case. We present a study that shows that the crack detection capabilities of laser thermography can be extended also to specimens at high temperature. A combination of inductive and laser heating allows to systematically study the contrast formation as well as the optimization of the important measurement parameters. The experiments are accompanied by FEM simulations that provide a better insight of the physical correlations and support the experimental developments. The aim of these studies is to develop a system with high inspection speed and detection performance to be in-line operated under the hostile environment of steel production lines. T2 - 19th World Conference on Non-Destructive Testing (WCNDT 2016) CY - Munich, Germany DA - 13.06.2016 KW - In-line Monitoring KW - Laser Infrared thermography KW - Cracks KW - Induction heating KW - Steel billets KW - FEM simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389161 UR - http://ndt.net/?id=19573 SN - 1435-4934 VL - 21 IS - 7 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-38916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jonietz, Florian A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Suwala, H. A1 - Rethmeier, Michael T1 - Untersuchung von Punktschweißverbindungen mit aktiver Thermografie N2 - Widerstandspunktschweißen ist insbesondere im Automobilbau eine der wichtigsten Fügetechniken. Bislang erfolgt die Qualitätssicherung überwiegend durch stichprobenartige zerstörende Prüfung. Eine zerstörungsfreie Prüftechnik würde neben der Reduzierung der Prüfkosten auch eine Optimierung des Punktschweißverfahrens bedeuten, da prinzipiell jeder Schweißpunkt geprüft werden könnte und somit auch eine Reduzierung der Anzahl der Schweißpunkte möglich ist. Es wird ein Verfahren vorgestellt, bei dem die Punktschweißverbindung zwischen zwei Stahlblechen optisch auf einer Blechseite mittels Laser oder Blitzlicht erwärmt wird. Die aufgeschmolzene Zone, die sogenannte Schweißlinse, stellt dabei neben der mechanischen Verbindung auch eine Wärmebrücke zwischen den beiden verschweißten Blechen dar, die bei diesem Verfahren ausgenutzt wird. Durch den verbesserten thermischen Kontakt zwischen den verschweißten Blechen an der Schweißlinse kontrastiert diese deutlich mit dem umgebenden Blechmaterial, bei dem der Wärmeübertrag zwischen den Blechen vergleichsweise gering ist. Dieser Kontrast im thermischen Verhalten kann mittels zeitabhängiger Thermografie gemessen werden. Durch das hier vorgestellte Verfahren kann mittels aktiver Thermografie sowohl in Transmissions- als auch in Reflexionsanordnung die Größe des thermischen Kontaktes zwischen den beiden Blechen ermittelt werden, welche ein Maß für die Größe der Schweißlinse und damit für die qualitative Güte der Schweißung darstellt. Ein Vorteil des entwickelten Verfahrens ist seine Anwendbarkeit auf Bleche ohne Oberflächenbehandlung. T2 - DACH-Jahrestagung 2015 CY - Salzburg, Austria DA - 11.05.2015 PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343476 UR - http://www.ndt.net/?id=19068 SN - 1435-4934 VL - 21 IS - 4 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-34347 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuroiwa, T. A1 - Zhu, Y. A1 - Inagaki, K. A1 - Long, S. A1 - Christopher, S. A1 - Puelles, M. A1 - Porinsky, M. A1 - Hatamleh, N. A1 - Murby, J. A1 - Merrick, J. A1 - White, I. A1 - Saxby, D. A1 - Caciano de Sena, R. A1 - Dominguez de Almeida, M. A1 - Vogl, Jochen A1 - Phukphatthanachai, Pranee A1 - Fung, W.-H. A1 - Yau, H.-P. A1 - Okumu, T. O. A1 - Kang'iri, J. N. A1 - Tellez, J. A. S. A1 - Campos, E. Z. A1 - Galvan, E. C. A1 - Kaewkhomdee, N. A1 - Taebunpakul, S. A1 - Thiengmanee, U. A1 - Yafa, C. A1 - Tokman, N. A1 - Tunc, M. A1 - Can, S. Z. T1 - Report of the CCQM-K123: trace elements in biodiesel fuel N2 - The CCQM-K123 key comparison was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of sodium, calcium, potassium, magnesium phosphorous and sulfur in biodiesel fuel (BDF). The National Metrology Institute of Japan (NMIJ) and National Institute of Standards and Technology (NIST) acted as the coordinating laboratories. Results were submitted by 11 NMIs and DIs. The participants used different measurement methods, though most of them used inductively coupled plasma-mass spectrometry (ICP-MS), isotope dilution technique with ICP-MS and inductively coupled plasma-optical emission spectrometry (ICP-OES) with microwave acid digestion. The material was quite challenging and a number of questions were raised at the IAWG meeting. Concerning S, the variation in S results between participants, particularly those using IDMS methods was discussed at the IAWG meeting. BAM, NIST and NMIJ reviewed their experimental conditions, results and/or uncertainty calculations for IDMS. According to the additional evaluation and investigation, the variances between the revised results became smaller than the original one, the revised results were overlapping between IDMS measurements of S content at the k=2 level. It is not possible to calculate a KCRV with values being modified after submission. It was concluded that this KC does not support S measurements. Accounting for relative expanded uncertainty, comparability of measurement results for each of Na, Ca, K, Mg and P was successfully demonstrated by the participating NMIs or DIs. It is expected that sodium, calcium, potassium, magnesium and phosphorus at mass fractions greater than approximately 0.1 mg/kg, 0.1 mg/kg, 0.05 mg/kg, 0.05 mg/kg and 0.1 mg/kg respectively in biodiesel fuel and similar matrices (fuels and oils etc.) can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report. Furthermore, the results of this key comparison can be utilized along with the IAWG core capability approach. KW - Biodiesel KW - Fuel KW - Sulphur KW - Reference measurement PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393941 UR - http://iopscience.iop.org/article/10.1088/0026-1394/54/1A/08008/meta DO - https://doi.org/10.1088/0026-1394/54/1A/08008 SN - 0026-1394 SN - 1681-7575 VL - 54 SP - Tech. Suppl. 2017, 08008, 1 EP - 47 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hsiao, I.-L. A1 - Bierkandt, Frank A1 - Reichardt, Ph. A1 - Luch, A. A1 - Huang, Y.-J. A1 - Jakubowski, Norbert A1 - Tentschert, J. A1 - Haase, A. T1 - Quantification and visualization of cellular uptake of TiO2 and Ag nanoparticles: comparison of different ICP-MS techniques N2 - Safety assessment of nanoparticles (NPs) requires techniques that are suitable to quantify tissue and cellular uptake of NPs. The most commonly applied techniques for this purpose are based on inductively coupled plasma mass spectrometry (ICP-MS). Here we apply and compare three different ICP-MS methods to investigate the cellular uptake of TiO2 (diameter 7 or 20 nm, respectively) and Ag (diameter 50 or 75 nm, respectively) NPs into differentiated mouse neuroblastoma cells (Neuro-2a cells). Cells were incubated with different amounts of the NPs. Thereafter they were either directly analyzed by laser ablation ICP-MS (LA-ICP-MS) or were lysed and lysates were analyzed by ICP-MS and by single particle ICP-MS (SP-ICP-MS). KW - Nanoparticles KW - Single particle ICP-MS KW - Laser ablation ICP-MS KW - Cellular internalization KW - Neurons PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371620 DO - https://doi.org/10.1186/s12951-016-0203-z SN - 1477-3155 VL - 14 SP - Article 50 AN - OPUS4-37162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asadujjaman, Asad A1 - Kent, B. A1 - Bertin, Annabelle T1 - Phase transition and aggregation behaviour of an UCST-type copolymer poly(acrylamide-coacrylonitrile) in water: effect of acrylonitrile content, concentration in solution, copolymer chain length and presence of electrolyte N2 - An UCST-type copolymer of acrylamide (AAm) and acrylonitrile (AN) (poly(AAm-co-AN)) was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization and its temperature-induced phase transition and aggregation behaviour studied by turbidimetry, static and dynamic light scattering, small angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM) measurements. The phase transition temperature was found to increase with increasing AN content in the copolymer, concentration of the solutions and copolymer chain length. A significant effect was observed onto the phase transition temperature by addition of different electrolytes into the copolymer solution. The copolymer chains were aggregated below the phase transition temperature and disaggregated above it. The size of the aggregates increases with increasing AN contents and concentration of the copolymer solutions below the phase transition temperature. The copolymer chains were expanded and weekly associated in solution above the phase transition temperature. A model is proposed to explain such association–aggregation behaviour of poly(AAm-co-AN) copolymers depending on AN contents and concentration of the copolymer solutions as a function of temperature. KW - Thermoresponsive polymers KW - UCST-type copolymer PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394636 DO - https://doi.org/10.1039/c6sm02262f SN - 1744-683X SN - 1744-6848 VL - 13 IS - 3 SP - 658 EP - 669 PB - RSC AN - OPUS4-39463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Weller, Michael G. T1 - Referee Report 06 March 2017 N2 - This article is a valuable and welcome contribution to the ongoing discussion of antibody quality. The suggestion of a two-tier approach is helpful to distinguish between simple descriptive data and the validation of an antibody for a specified application. KW - Antibody KW - Validation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393333 UR - https://f1000research.com/articles/6-161/v1#referee-response-20349 DO - https://doi.org/10.5256/f1000research.11700.r20349 SN - 2046-1402 SP - 6 EP - 7 PB - F1000 Research Ltd. CY - London AN - OPUS4-39333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Heyn, A. T1 - Dynamic tafel factor adaption for the evaluation of instantaneous corrosion rates on zinc by using gel-type electrolytes N2 - The paper presents a new method for the determination and evaluation of tafel factors using gel-type electrolytes and electrochemical frequency modulation technique (EFM). This relatively new electrochemical method offers the possibility to determine both polarization resistances and tafel factors within one measurement and in short measuring intervals. Starting from a comprehensive parameter study it is shown that a direct relationship between the two values exists that can be described mathematically. This contribution presents the determined tafel factors for the system gel-type electrolyte/zinc and discusses their applicability and their limits. T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 16.03.2017 KW - Gel-type electrolytes KW - Gelartige Elektrolyte KW - Zinc KW - Zink KW - Stern Geary constant KW - Stern-Geary-Konstante PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394324 UR - http://iopscience.iop.org/article/10.1088/1757-899X/181/1/012021/pdf DO - https://doi.org/10.1088/1757-899X/181/1/012021 SN - 1757-899X SN - 1757-8981 VL - 181 IS - Conference 1 SP - Article UNSP 012021, 1 EP - 11 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Krebber, Katerina ED - Harun, S.W. ED - Arof, H. T1 - Smart technical textiles based on fiber optic sensors N2 - Smart technical textiles are by definition textiles that can interact with their environment. They can sense and react to environmental conditions and external stimuli from mechanical, thermal, chemical or other sources. Such textiles are multifunctional or even “intelligent” which is fulfilled by a number of sensors incorporated in the textiles. The embedded sensors are sensitive to various parameters such as temperature, strain, chemical, biological and other substances. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289397 SN - 978-953-51-1148-1 DO - https://doi.org/10.5772/54244 IS - Section 3 / Chapter 12 SP - 319 EP - 344 PB - InTech AN - OPUS4-28939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Sproesser, G. A1 - Change, Y.-J. A1 - Pittner, Andreas A1 - Finkbeiner, M. A1 - Rethmeier, Michael ED - Stark, R. ED - Bonvoisin, J. ED - Seliger, G. T1 - Sustainable technologies for thick metal plate welding N2 - Welding is the most important joining technology. In the steel construction industry, e.g. production of windmill sections, welding accounts for a main part of the manufacturing costs and resource consumption. Moreover, social issues attached to welding involve working in dangerous environments. This aspect has unfortunately been neglected so far, in light of a predominant focus on economics combined with a lack of suitable assessment methods. In this chapter, exemplary welding processes are presented that reduce the environmental and social impacts of thick metal plate welding. Social and environmental Life Cycle Assessments for a thick metal plate joint are conducted for the purpose of expressing and analysing the social and environmental impacts of welding. Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase social and environmental performance in contrast to common technologies, and therefore offer great potential for sustainable manufacturing. KW - Human health G. KW - Life cycle assessment (LCA) KW - Arc welding KW - Laser arc-hybrid welding KW - Resource efficiency KW - Social life cycle assessment (SLCA) PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390025 SN - 978-3-319-48513-3 SN - 978-3-319-48514-0 DO - https://doi.org/10.1007/978-3-319-48514-0 SN - 2194-0541 SN - 2194-055X SP - 71 EP - 84 PB - Springer CY - Cham, Switzerland AN - OPUS4-39002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rabin, Ira ED - Wandrey, T1 - Building a bridge from the Dead Sea Scrolls N2 - As part of the Qumran project conducted at the Federal Institute for Materials Research and Testing (BAM) in Berlin between 2007 and 2010, my colleagues and I developed a new, integrated methodology for determining the original and acquired properties of highly heterogeneous Dead Sea Scrolls. The purpose of this methodology is to help scholars determine the provenance of fragments of the scrolls and sort and compare them more easily than in the past. Since our measurements allowed us to differentiate between the minerals originating from the production processes and the sediments accrued during storage in the caves in Qumran, we were able to reconstruct the treatment of hides and discovered that at least two distinct parchmentproduction techniques co-existed at the beginning of the common era. The reconstruction of workmanship on animal hides in Antiquity raised doubts about the validity of the current definition of parchment, which is based on a production technique known from the Middle Ages. We hope that our current work will also help researchers understand the characteristic properties of gewil, qelaf and dukhsustos better.¹ The evolution and socio-geographic distribution of writing inks in late Antiquity and the early Middle Ages are the second focus of our investigative work at BAM. We use X-ray fluorescence analysis (XRF) to determine the chemical composition of inks and NIR reflectography for their typology. We are amply assisted in our ambitious enterprise by codicologists and palaeographers who have adopted our methodology and conduct field studies of their own. KW - Dead Sea Scrolls KW - Medieval Jewish manuscripts KW - Material analysis PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435582 DO - https://doi.org/10.1515/9783110546422-0002 VL - 13 SP - 309 EP - 321 PB - de Gruyter CY - Berlin AN - OPUS4-43558 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taffe, Alexander A1 - Spies, M. A1 - Recknagel, J. T1 - Schulung zur zuverlässigen Ortung von Bewehrung in Stahlbetonbauteilen von Kraftwerken N2 - In kerntechnischen Anlagen werden Revisionszeiträume genutzt, um unter anderem Anlagenteile nach dem Stand der Technik zu ertüchtigen und um Nachrüstungsmaßnahmen zur Erhöhung der Betriebssicherheit durchzuführen. Solche Anlagenteile werden häufig mittels Dübelplatten befestigt. Die Dübel sind in Stahlbetonbauteile einzubringen, die kraftwerkstypisch mit dichter Bewehrung versehen sind. Zerstörungsfreie Untersuchungen zur genauen Ortung bewehrungsfreier Orte sind hierzu erforderlich. Bei dieser vermeintlich einfachen Prüfaufgabe wurde deutlich, dass in der Praxis Bedarf an verbesserter Anwendungssicherheit der zur Verfügung stehenden ZFP-Verfahren besteht, die eng mit der Ausbildung von Prüfern verbunden ist. Dieser Beitrag berichtet über die bislang im Bereich ZfPBau erstmalig umgesetzte Strategie aus Verfahrensanweisung und Schulung zur zuverlässigen Ortung von Bewehrung an Stahlbetonbauteilen. Sie kann als Muster für weitere ZfPBau-Schulungen zur zuverlässigen Anwendung der Verfahren dienen. T2 - Fachtagung Bauwerksdiagnose 2012 - Praktische Anwendungen zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Germany DA - 23.02.2012 KW - Zerstörungsfreie Prüfung im Bauwesen KW - ZfPBau KW - Ausbildung KW - Bewehrungsortung KW - Bauwerksdiagnose KW - Kernkraftwerk KW - Bauwerksprüfung PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285909 UR - https://bauwerksdiagnose2012.dgzfp.de/Portals/bwd2012/Dokumente/bb/v04.pdf SN - 978-3-940283-40-5 IS - DGZfP BB 134 SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-28590 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taffe, Alexander A1 - Spies, M. A1 - Recknagel, J. A1 - Rieß, H. T1 - Schulung zur zuverlässigen Ortung von Bewehrung in Stahlbetonbauteilen von Kraftwerken N2 - In kerntechnischen Anlagen werden Revisionszeiträume genutzt, um unter anderem Anlagenteile nach dem Stand der Technik zu ertüchtigen und um Nachrüstungsmaßnahmen zur Erhöhung der Betriebssicherheit durchzuführen. Solche Anlagenteile werden häufig mittels Dübelplatten befestigt. Die Dübel sind in Stahl-betonbauteile einzubringen, die kraftwerkstypisch mit dichter Bewehrung versehen sind. Zerstörungsfreie Untersuchungen zur genauen Ortung bewehrungsfreier Orte sind hierzu erforderlich. Bei dieser vermeintlich einfachen Prüfaufgabe wurde deutlich, dass in der Praxis Bedarf an verbesserter Anwendungssicherheit der zur Verfügung stehenden ZFP-Verfahren besteht, die eng mit der Ausbildung von Prüfern verbunden ist. Dieser Beitrag berichtet über die bislang im Bereich ZfPBau erstmalig umgesetzte Strategie aus Verfahrensanweisung und Schulung zur zuverlässigen Ortung von Bewehrung an Stahlbetonbauteilen. Sie kann als Muster für weitere ZfPBau-Schulungen zur zuverlässigen Anwendung der Verfahren dienen. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Germany DA - 30.05.2011 KW - Zerstörungsfreie Prüfung im Bauwesen KW - Ausbildung KW - Bewehrungsortung KW - Performance demonstration KW - Blindtest KW - Wirbelstrom KW - Radar PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253752 UR - https://jt2011.dgzfp.de/Portals/jt2011/BB/di2b1.pdf SN - 978-3-940283-33-7 IS - DGZfP BB 127 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-25375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illerhaus, Bernhard A1 - Onel, Yener T1 - Mehr Strom oder mehr Spannung, ein Vergleich drei Röntgenröhren in der CT N2 - Sollten CT Aufnahmen quantitativ und automatisch ausgewertet werden, ist die Qualität der Tomogramme ein wesentlicher Punkt. Außerdem steht bei Serienmessungen nur eine begrenzte Meßzeit für jede Probe. Es werden die verschiedenen Mikrofokusröhren in Bezug auf die Parameter Orts- und Dichteauflösung, sowie Meßzeit verglichen, CT Beispiele dazu gezeigt. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Computertomographie KW - Ortsauflösung KW - Röhrenvergleich PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-307629 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1A.1, 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-30762 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lück, S. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Schmidt, V. T1 - Statistical analysis of tomographic reconstruction algorithms by morphological image characteristics N2 - We suggest a procedure for quantitative quality control of tomographic reconstruction algorithms. Our task-oriented evaluation focuses on the correct reproduction of phase boundary length and has thus a clear implication for morphological image analysis of tomographic data. Indirectly the method monitors accurate reproduction of a variety of locally defined critical image features within tomograms such as interface positions and microstructures, debonding, cracks and pores. Tomographic errors of such local nature are neglected if only global integral characteristics such as mean squared deviation are considered for the evaluation of an algorithm. The significance of differences in reconstruction quality between algorithms is assessed using a sample of independent random scenes to be reconstructed. These are generated by a Boolean model and thus exhibit a substantial stochastic variability with respect to image morphology. It is demonstrated that phase boundaries in standard reconstructions by filtered backprojection exhibit substantial errors. In the setting of our simulations, these could be significantly reduced by the use of the innovative reconstruction algorithm DIRECTT. KW - Tomography KW - Computed tomography KW - Reconstruction algorithm KW - Morphological image analysis KW - Phase boundary KW - Metrology KW - Non-destructive testing PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-210710 DO - https://doi.org/10.5566/ias.v29.p61-77 SN - 1580-3139 SN - 1854-5165 VL - 29 SP - 61 EP - 77 CY - Ljubljana, Slovenia AN - OPUS4-21071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drogan, D. A1 - Sheldrick, A. J. A1 - Schütze, M. A1 - Knüppel, S. A1 - Andersohn, F. A1 - di Giuseppe, R. A1 - Herrmann, Bianca A1 - Willich, S. N. A1 - Garbe, E. A1 - Bergmann, M. M. A1 - Boeing, H. A1 - Weikert, C. T1 - Alcohol consumption, genetic variants in alcohol deydrogenases, and risk of cardiovascular diseases: A prospective study and meta-analysis N2 - Objective: First, to investigate and compare associations between alcohol consumption and variants in alcohol dehydrogenase (ADH) genes with incidence of cardiovascular diseases (CVD) in a large German cohort. Second, to quantitatively summarize available evidence of prospective studies on polymorphisms in ADH1B and ADH1C and CVD-risk. Methods: We conducted a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort including a randomly drawn subcohort (n = 2175) and incident cases of myocardial infarction (MI; n = 230) or stroke (n = 208). Mean follow-up time was 8.2±2.2 years. The association between alcohol consumption, ADH1B or ADH1C genotypes, and CVD-risk was assessed using Cox proportional hazards regression. Additionally, we report results on associations of variants in ADH1B and ADH1C with ischemic heart disease and stroke in the context of a meta-analysis of previously published prospective studies published up to November 2011. Results: Compared to individuals who drank >0 to 6 g alcohol/d, we observed a reduced risk of MI among females consuming >12 g alcohol/d (HR = 0.31; 95% CI: 0.10–0.97) and among males consuming >24 to 60 g/d (HR = 0.57; 95% CI: 0.33–0.98) or >60 g alcohol/d (HR = 0.30; 95% CI: 0.12–0.78). Stroke risk was not significantly related to alcohol consumption >6 g/d, but we observed an increased risk of stroke in men reporting no alcohol consumption. Individuals with the slowcoding ADH1B*1/1 genotype reported higher median alcohol consumption. Yet, polymorphisms in ADH1B or ADH1C were not significantly associated with risk of CVD in our data and after pooling results of eligible prospective studies [ADH1B*1/1: RR = 1.35 (95% CI: 0.98–1.88; p for heterogeneity: 0.364); ADH1C*2/2: RR = 1.07 (95% CI: 0.90–1.27; p for heterogeneity: 0.098)]. Conclusion: The well described association between alcohol consumption and CVD-risk is not reflected by ADH polymorphisms, which modify the rate of ethanol oxidation. KW - Coronary heart disease KW - Myocardial infarction KW - Dehydrogenase KW - Genotypes KW - Relative validity KW - Drinking habits KW - EPIC-Potsdam Study KW - German part KW - Case cohort KW - Stroke KW - Reproducibility PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633710 DO - https://doi.org/10.1371/journal.pone.0032176 SN - 1932-6203 N1 - The recruitment phase of the EPIC-Potsdam Study was supported by the Federal Ministry of Science, Germany (01 EA 9401), and the European Union (SOC 95201408 05F02). The follow-up was supported by the German Cancer Aid (70-2488-Ha I) and the European Community (SOC 98200769 05F02). VL - 7 IS - 2 SP - 1 EP - 11 PB - Public Library of Science (PLoS) CY - San Francisco, California, US AN - OPUS4-63371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Werner A1 - Saathoff, F. T1 - Geosynthetics in geoenvironmental engineering N2 - Geosynthetics are planar polymeric products, which are used in connection with soil, rock or other soil-like materials to fulfill various functions in geoenvironmental engineering. Geosynthetics are of ever-growing importance in the construction industry. Sealing of waste storage facilities to safely prevent the emission of wastewater, landfill gas and contaminated dust as well as the diffusion of pollutants into the environment and coastal protection against storms and floods and reconstruction after natural disaster are important fields of application. We will give an overview of the various geosynthetic products. Two examples of the material problems related to geosynthetics are discussed in detail: the effect of creep on the long-term performance of geocomposite drains and the numerical simulation of the interaction of soil with geogrids. Both issues are of importance for the use of these products in landfill capping systems. The various functions, which geosynthetics may fulfill in the protection of coastal lines, are illustrated by case studies. The geosynthetic market is evaluated and economical and environmental benefits, as well as environmental side effects related to the use of geosynthetics, are discussed. KW - Geosynthetics KW - Geoenvironmental engineering KW - Landfill capping system KW - Coastal protection KW - Geocomposite drain KW - Geogrid KW - Geotextile PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332014 DO - https://doi.org/10.1088/1468-6996/16/3/034605 SN - 1468-6996 VL - 16 IS - 3 SP - 034605-1 EP - 034605-20 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-33201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilhelm, Stefan A1 - Kaiser, Martin A1 - Würth, Christian A1 - Heiland, J. A1 - Carrillo-Carrion, C. A1 - Muhr, V. A1 - Wolfbeis, Otto S. A1 - Parak, W.J. A1 - Resch-Genger, Ute A1 - Hirsch, T. T1 - Water dispersible upconverting nanoparticles: effects of surface modification on their luminescence and colloidal stability N2 - We present a systematic study on the effect of surface ligands on the luminescence properties and colloidal stability of β-NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs), comparing nine different surface coatings to render these UCNPs water-dispersible and bioconjugatable. A prerequisite for this study was a large-scale synthetic method that yields ~2 g per batch of monodisperse oleate-capped UCNPs providing identical core particles. These ~23 nm sized UCNPs display an upconversion quantum yield of ~0.35% when dispersed in cyclohexane and excited with a power density of 150 W cm-2, underlining their high quality. A comparison of the colloidal stability and luminescence properties of these UCNPs, subsequently surface modified with ligand exchange or encapsulation protocols, revealed that the ratio of the green (545 nm) and red (658 nm) emission bands determined at a constant excitation power density clearly depends on the surface chemistry. Modifications relying on the deposition of additional (amphiphilic) layer coatings, where the initial oleate coating is retained, show reduced non-radiative quenching by water as compared to UCNPs that are rendered water-dispersible via ligand exchange. Moreover, we could demonstrate that the brightness of the upconversion luminescence of the UCNPs is strongly affected by the type of surface modification, i.e., ligand exchange or encapsulation, yet hardly by the chemical nature of the ligand. KW - upconverting nanoparticles (UCNPs) KW - Luminescence KW - surface modification PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324071 DO - https://doi.org/10.1039/c4nr05954a SN - 2040-3364 SN - 2040-3372 VL - 7 IS - 4 SP - 1403 EP - 1410 PB - RSC Publ. CY - Cambridge AN - OPUS4-32407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heyn, A. A1 - Müller, Thoralf A1 - Balzer, M. A1 - Fenker, M. A1 - Kappl, H. T1 - Corrosion protection mechanisms of TiMgN hard coatings on steel N2 - Hard coated steel components are used in a wide application range, mostly for protective, wear resistant and decorative purposes. Despite of these coatings being regarded as relatively dense, there is always a high risk of localized corrosion when a coated low alloyed steel component encounters a surrounding high humidity atmosphere or even an aqueous medium. An approach to enhance the corrosion properties is the addition of magnesium to physical vapor deposited hard coatings, like TiN. It has been found that there is a remarkable increase in corrosion resistance in dependence of magnesium content of the TiMgN coating and its surface properties. In this work the authors will explain the underlying corrosion protection mechanisms by means of electrochemical and analytical studies. The positive impact of magnesium in the coating relates on its preferred dissolution vs. steel. This causes the potential to shift to more negative direction with respect to the steel substrate and additionally leads to a temporarily passivation of the steel due to alkalization of the surrounding electrolyte by formation of magnesium hydroxide. T2 - 20. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 14.03.2018 KW - Corrosion KW - Titanium nitride KW - PVD hard coating KW - magnesium PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457117 DO - https://doi.org/10.1088/1757-899X/373/1/012009 SN - 1757-8981 VL - 373 IS - 1 SP - 012009, 1 EP - 10 PB - IOP Publishing Ltd AN - OPUS4-45711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiegner, Katharina A1 - Hahn, Oliver A1 - Horn, Wolfgang A1 - Farke, M. A1 - Kalus, Sabine A1 - Nohr, Michael A1 - Jann, Oliver T1 - Determination of formic and acetic acid emissions in indoor air or from building products N2 - Several construction and building materials, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs) and volatile organic compounds (VOCs) like formic and acetic acid. Due to very high air tightness and very low air exchange rates in new buildings concentrations of these harmful substances can increase considerably. To minimize the risk, emissions from building products should be identified and quantified. With the common standard method, this means Tenax® sampling followed by thermal desorption and GC-MS analysis, these acids could not be detected sufficiently. The aim oft this study is the comparison of two different methods for the determination of acetic and formic acid. The sampling of method one, which is usually used for identification and quantification of VOCs, is done in accordance with ISO 16000-6 and ISO 16017-1 on Carbotrap® 202 multi-bed thermal desorption tube by subsequent identification and quantification with GC-MS. Method two is based on sampling on 2,4-dinitrophenylhydrazine (DNPH) cartridges, derivatisation, elution, identification and quantification of the derivatives with LC-MS/MS (liquid chromatography – mass spectrometry/mass spectrometry). N2 - Viele Konstruktions- und Baumaterialien, wie Holz, Kleber und Anstriche, sind mögliche Quellen für leicht flüchtige organische Verbindungen (VVOC) und flüchtige organische Verbindungen (VOC), wie Ameisen- und Essigsäure. Bedingt durch die hohe Dichtigkeit und den damit verbundenen niedrigen Luftwechsel in neuen Gebäuden können die Konzentrationen dieser gesundheitsgefährdenden Substanzen beträchtlich ansteigen. Um das Risiko zu minimieren, sollen Emissionen aus Bauprodukten identifiziert und quantifiziert werden. Mit der üblichen Standardmethode, die auf einer Luftprobenahme auf Tenax® und anschließender Analyse mittels GC-MS basiert, können diese Säuren nicht ausreichend detektiert werden. Ziel dieser Arbeit ist der Vergleich von zwei unterschiedlichen Methoden zur Bestimmung von Essig- und Ameisensäure. Die Luftprobenahme der ersten Methode, die üblicherweise zur Identifizierung und Quantifizierung von VOC genutzt wird, wurde gemäß ISO 16000-6 and ISO 16017-1 auf Carbotrap® 202, ein mit mehreren Adsorbentien gepacktes Thermodesorptionsrohr, mit anschließender Identifikation und Quantifizierung mittels GC-MS durchgeführt. Die zweite Methode basiert auf einer Luftprobenahme mittels 2,4-Dinitrophenylhydrazin-(DNPH)-Kartuschen, Derivatisierung, Elution, Identifikation und Quantifizierung der Derivate mit LC-MS/MS (Flüssigkeitschromatographie – Massenspektometrie/Massenspektometrie). KW - Formic acid KW - Acetic acid KW - VVOCs KW - Air sampling KW - DNPH PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-255911 UR - http://www.gefahrstoffe.de/gest/article.php?data[article_id]=65887 SN - 0949-8036 SN - 0039-0771 SN - 1436-4891 VL - 72 IS - 3 SP - 84 EP - 88 PB - Springer-VDI-Verlag CY - Düsseldorf AN - OPUS4-25591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chowdhary, S. A1 - Moschner, J. A1 - Mikolajczak, D. J. A1 - Becker, M. A1 - Thünemann, Andreas A1 - Kästner, Claudia A1 - Klemczak, D. A1 - Stegemann, A.-K. A1 - Böttcher, C. A1 - Metrangolo, P. A1 - Netz, R. R. A1 - Koksch, B. T1 - The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation N2 - The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Nanostructure KW - Peptide KW - Amyloid PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518632 DO - https://doi.org/10.1002/cbic.202000373 VL - 21 IS - 24 SP - 3544 EP - 3554 PB - Wiley CY - Weinheim AN - OPUS4-51863 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, B. A1 - Meyer, T. A1 - Sieg, H. A1 - Kästner, Claudia A1 - Reichardt, P. A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Estrela-Lopis, I. A1 - Burel, A. A1 - Chevance, S. A1 - Gauffre, F. A1 - Jalili, P. A1 - Meijer, J. A1 - Böhmert, L. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Emmerling, Franziska A1 - Fessard, V. A1 - Laux, P. A1 - Lampen, A. A1 - Luch, A. T1 - Characterization of aluminum, aluminum oxide and titanium dioxide nanomaterials using a combination of methods for particle surface and size analysis N2 - The application of appropriate analytical techniques is essential for nanomaterial (NM) characterization. In this study, we compared different analytical techniques for NM analysis. Regarding possible adverse health effects, ionic and particulate NM effects have to be taken into account. As NMs behave quite differently in physiological media, special attention was paid to techniques which are able to determine the biosolubility and complexation behavior of NMs. Representative NMs of similar size were selected: aluminum (Al0) and aluminum oxide (Al2O3), to compare the behavior of metal and metal oxides. In addition, titanium dioxide (TiO2) was investigated. Characterization techniques such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were evaluated with respect to their suitability for fast characterization of nanoparticle dispersions regarding a particle's hydrodynamic diameter and size distribution. By application of inductively coupled plasma mass spectrometry in the single particle mode (SP-ICP-MS), individual nanoparticles were quantified and characterized regarding their size. SP-ICP-MS measurements were correlated with the information gained using other characterization techniques, i.e. transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The particle surface as an important descriptor of NMs was analyzed by X-ray diffraction (XRD). NM impurities and their co-localization with biomolecules were determined by ion beam microscopy (IBM) and confocal Raman microscopy (CRM). We conclude advantages and disadvantages of the different techniques applied and suggest options for their complementation. Thus, this paper may serve as a practical guide to particle characterization techniques. KW - Small-angle X-ray scattering KW - SAXS PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447057 DO - https://doi.org/10.1039/C8RA00205C SN - 2046-2069 VL - 8 IS - 26 SP - 14377 EP - 14388 PB - The Royal Society of Chemistry AN - OPUS4-44705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -