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 - 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 - 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 - JOUR A1 - Mundra, S. A1 - Bernal, S. A. A1 - Criado, M. A1 - Hlaváček, Petr A1 - Ebell, Gino A1 - Reinemann, Steffi A1 - Gluth, Gregor A1 - Provis, J. L. T1 - Steel corrosion in reinforced alkali‐activated materials N2 - The development of alkali‐activated materials (AAMs) as an alternative to Portland cement (PC) has seen significant progress in the past decades. However, there still remains significant uncertainty regarding their long term performance when used in steel‐reinforced structures. The durability of AAMs in such applications depends strongly on the corrosion behaviour of the embedded steel reinforcement, and the experimental data in the literature are limited and in some cases inconsistent. This letter elucidates the role of the chemistry of AAMs on the mechanisms governing passivation and chloride‐induced corrosion of the steel reinforcement, to bring a better understanding of the durability of AAM structures exposed to chloride. The corrosion of the steel reinforcement in AAMs differs significantly from observations in PC; the onset of pitting (or the chloride ‘threshold’ value) depends strongly on the alkalinity, and the redox environment, of these binders. Classifications or standards used to assess the severity of steel corrosion in PC appear not to be directly applicable to AAMs due to important differences in pore solution chemistry and phase assemblage. KW - Corrosion KW - Alkali-activated PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435162 DO - https://doi.org/10.21809/rilemtechlett.2017.39 SN - 2518-0231 VL - 2 SP - 33 EP - 39 PB - RILEM Publications SARL CY - Paris, France AN - OPUS4-43516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, M. F. A1 - Fischer, M. A1 - Radtke, Martin A1 - Reinholz, Uwe T1 - Inca figurines from the Ethnologisches Museum in Berlin: an analytical study of some typical and atypical productions N2 - Fourteen hollow and one cast anthropomorphic and zoomorphic figurines produced in Incan times for ritual offerings from the Ethnologisches Museum in Berlin were selected to investigate the technologies and alloys used for their fabrication with portable optical microscopy and non-destructive XRF elemental analysis. This group of gold and silver figurines includes typical specimens of the Inca production, such as the four silver figurines from the Island Coati in Lake Titicaca and the two gold figurines from Pachacamac, as well as specimens that are seldom present in collections, which makes them atypical. In addition to the tall figurines with atypical hair or standing pose, one bicolour figurine half silver, half gold) and another with coloured inlays were included in this study for comparison. The large majority of the silver specimens are made from very high quality alloys and the gold figurines are made from alloys containing low copper contents and silver ranging from 30wt% to 52wt%. KW - Gold KW - pXRF KW - Inca PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436015 DO - https://doi.org/10.4000/bifea.8232 SN - 0303-7495 VL - 46 IS - 1 SP - 221 EP - 251 PB - Institut Français d'Études Andines AN - OPUS4-43601 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rauwolf, M. A1 - Turyanskaya, A. A1 - Roschger, A. A1 - Prost, J. A1 - Simon, R. A1 - Scharf, O. A1 - Radtke, Martin A1 - Schoonjans, Tom A1 - de Oliveira Guilherme Buzanich, Ana A1 - Klaushofer, K. A1 - Wobrauschek, P. A1 - Hofstaetter, J. G. A1 - Roschger, P. A1 - Streli, C. T1 - Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups N2 - In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-mXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its K alpha XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution. KW - Synchrotron KW - BAMline KW - BESSY KW - XRF KW - X-ray Color Camera PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391944 DO - https://doi.org/10.1107/S1600577516017057 SN - 1600-5775 VL - 24 SP - 307 EP - 311 PB - International Union of Crystallography AN - OPUS4-39194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram A1 - Wossidlo, Peter T1 - Validation of a low blow specimen technique for R-curve determination using a drop tower N2 - Fracture mechanics based component design requires appropriate fracture mechanics toughness data with respect to both, loading rate as well as test temperature. Taking high-rate loading into account such as with accidental scenarios, different standards such as ASTM E 1820 or BS 7448-3 provide some information on dynamic fracture mechanics testing. Nevertheless, the designations differ so that a validation of the own material specific test method used for dynamic R-curve determination is mandatory. In order to address this for ductile cast iron materials an experimental method for the reliable determination of dynamic J-integral crack resistance curves at -40 °C following the multiple specimen approach has been established and validated. The experimental concept offers some additional valuable features. Single values of dynamic crack initiation toughness can be determined using a single specimen technique based on crack sensors. Furthermore, an experimentally independent method is provided according to which CTOD δ5 R-curves can be established. The focus of the present paper is on the validation of the experimental low blow technique using a drop tower test system. A drop tower test system was developed and set up to perform low blow tests at temperatures down to -40 °C. The system allows for a variation of the impact mass and height and was optimized for testing of ductile cast iron at stress intensity rates from approximately 5∙10⁴ to 3∙10⁵ MPa√ms⁻¹. This range of loading rate is characteristic for instance with crash scenarios of heavy sectioned DCI casks for radioactive materials. In order to address characteristic challenges of impact tests (test duration of microseconds up to milliseconds, inertial effects, signal oscillations), an appropriate full bridge strain gage method for the measurement of force directly on the specimen as well as a non-contact measurement of load line displacement using an optical extensometer have been developed and validated. The low blow test requires either to prevent bouncing strikes of the hammer by using the stop block technique or to catch the hammer after its first strike. Both options are not part of the experimental concept and setup which have been realized here. The paper describes investigations which have been performed in order to make sure that bouncing strikes of the hammer do not cause additional crack extension in the specimen. This is necessary to ensure a unique relation between the work done and the achieved crack extension. The investigations covered the analysis of limit loads of the specimen with respect to the measured force. The measured stiffness of the specimen was assessed and signals of crack sensors were analyzed. Furthermore, an analysis of the mechanical behavior of the loading system and the specimen by optical observation was performed. Corresponding results are discussed in the paper. It had finally been proven that additional crack extension in the specimen due to bouncing strikes of the hammer is not to be expected under the given conditions of test setup, material and loading. It can be seen as a major experimental advantage that the striker does not have to be catched after the low blow test. T2 - XXIV Italian Group of Fracture Conference CY - Urbino, Italy DA - 01.03.2017 KW - Dynamic fracture mechanics KW - R-curve KW - Low blow KW - Ductile cast iron PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437686 DO - https://doi.org/10.1016/j.prostr.2017.04.005 SN - 2452-3216 VL - 3 SP - 25 EP - 32 AN - OPUS4-43768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baensch, Franziska A1 - Hussels, Maria-Teresa A1 - Chruscicki, Sebastian A1 - Baer, Wolfram A1 - Wossidlo, Peter A1 - Homann, Tobias A1 - Prager, Jens A1 - Schmidt, Dirk A1 - Weltschev, Margit A1 - Habib, Abdel Karim T1 - BAM-Projekt AGIFAMOR – Zustandsüberwachung von Rohrleitungen N2 - Rohrleitungssysteme sind aufgrund ihrer Funktion und Ausdehnung für den Betrieb, die Verfügbarkeit und die Sicherheit von Industrieanlagen von besonderer Bedeutung. Die bisher in definierten Intervallen durchgeführten, wiederkehrenden Prüfungen zur Sicherstellung leckagefreier Rohrleitungen sind kostenintensiv und mit einem erhöhten Aufwand verbunden. Mit dem interdisziplinären Forschungsprojekt AGIFAMOR (Ageing Infrastructures – Akustisches Monitoring von Rohrleitungen) arbeitet die BAM an der Entwicklung und Erprobung einer örtlich und zeitlich kontinuierlichen Zustandsüberwachung von Rohrleitungen basierend auf einem faseroptischen akustischen Messsystem, welches einen vergleichsweise geringen Installationsaufwand der Sensoren erfordert. Mit diesem Verfahren sollen vor allem betriebsbedingte Schädigungen infolge von Korrosion sowie daraus entstehende Pittings oder Risse erkannt und damit Leckagen verhindert werden. Im Rahmen einer Machbarkeitsstudie zum Teilaspekt „Detektion von Risswachstum“ wurde ein 2,5 m langes, definiert vorgekerbtes Stahlrohr mit der faseroptischen Sensorik (FOS) ausgestattet und quasistatisch unter 4-Punkt-Biegung belastet. Mit fortschreitender Belastung wächst, ausgehend vom vorhandenen Außenumfangskerb, ein Riss im Stahlrohr bis zum Erreichen der Leckage – in der Praxis ein gefährliches Schadensszenario. Parallel zur FOS erfolgten Messungen mit Schallemissionssensoren, Beschleunigungssensoren und Potentialsonden, deren Ergebnisse die Interpretation der FOS-Messergebnisse unterstützen sollen. T2 - 21. Kolloquium Schallemission CY - Fulda, Germany DA - 09.03.2017 KW - Beschleunigungssensoren KW - Faseroptische Sensorik KW - Schallemission KW - Monitoring KW - Rohrleitung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-401811 SN - 978-3-940283-82-5 VL - DGZfP-BB 159 SP - Vortrag 17, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-40181 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ha, Q. L. M. A1 - Armbruster, U. A1 - Atia, Hanan A1 - Lund, H. A1 - Agostini, G. A1 - Radnik, Jörg A1 - Vuong, H. T. A1 - Martin, A. T1 - Development of active and stable low nickel content catalysts for dry reforming of methane N2 - Methane dry reforming (DRM) was investigated over highly active Ni catalysts with low metal content (2.5wt%) supported on Mg-Al mixed oxide. The aim was to minimize carbon Deposition and metal sites agglomeration on the working catalyst which are known to cause catalyst deactivation. The solids were characterized using N2 adsorption, X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results showed that MgO-Al2O3 solid solution phases are obtained when calcining Mg-Al hydrotalcite precursor in the temperature range of 550–800 °C. Such phases contribute to the high activity of catalysts with low Ni content even at low temperature (500 °C). Modifying the catalyst preparation with citric acid significantly slows the coking rate and reduces the size of large octahedrally coordinated NiO-like domains, which may easily agglomerate on the surface during DRM. The most effective Ni catalyst shows a stable DRM course over 60 h at high weight hourly space velocity with very low coke deposition. This is a promising result for considering such catalyst systems for further development of an industrial DRM technology. KW - Dry reforming of methane KW - Carbon dioxide KW - Ni PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402904 DO - https://doi.org/10.3390/catal7050157 SN - 2073-4344 VL - 7 IS - 5 SP - 157, 1 EP - 157, 17 PB - MDPI AN - OPUS4-40290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abbas, F. A1 - Donskyi, Ievgen A1 - Gholami, M. A1 - Ziem, B. A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Böttcher, C. A1 - Rabe, J. A1 - Haag, R. A1 - Adeli, M. T1 - Controlled covalent functionalization of thermally reduced graphene oxide to generate defined bifunctional 2D nanomaterials N2 - A controlled, reproducible, gram-scale method is reported for the covalent functionalization of graphene Sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. The reaction between commercially available 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized sheets. The different reactivities of the chlorine substituents on the functionalized graphene allow stepwise post-modification by manipulating the temperature. This new method provides unique access to defined bifunctional 2D nanomaterials, as exemplified by chiral surfaces and multifunctional hybrid architectures. KW - Graphene oxide KW - Bifunctional 2D nanomaterials KW - XPS KW - NEXAFS KW - AFM PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394789 DO - https://doi.org/10.1002/ange.201612422 SN - 1433-7851 VL - 56 IS - 10 SP - 2675 EP - 2679 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-39478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abbas, Ioana M. A1 - Schwaar, Timm A1 - Bienwald, Frank A1 - Weller, Michael G. T1 - Predictable Peptide Conjugation Ratios by Activation of Proteins with Succinimidyl Iodoacetate (SIA) N2 - The small heterobifunctional linker succinimidyl iodoacetate (SIA) was examined for the preparation of peptide–protein bioconjugates with predicable conjugation ratios. For many conjugation protocols, the protein is either treated with a reductant to cleave disulfide bonds or is reacted with thiolation chemicals, such as Traut’s reagent. Both approaches are difficult to control, need individual optimization and often lead to unsatisfactory results. In another popular approach, a heterobifunctional linker with a N-hydroxysuccinimide (NHS) and a maleimide functionality is applied to the protein. After the activation of some lysine ε-amino groups with the NHS ester functionality, a cysteine-containing peptide is attached to the activated carrier protein via maleimide. Particularly, the maleimide reaction leads to some unwanted byproducts or even cleavage of the linker. Many protocols end up with conjugates with unpredictable and irreproducible conjugation ratios. In addition, the maleimide-thiol addition product should be assumed immunogenic in vivo. To avoid these and other disadvantages of the maleimide approach, we examined the known linker succinimidyl iodoacetate (SIA) in more detail and developed two protocols, which lead to peptide–protein conjugates with predefined average conjugation ratios. This holds potential to eliminate tedious and expensive optimization steps for the synthesis of a bioconjugate of optimal composition. KW - Bioconjugate KW - Carrier protein KW - Immunogen KW - Hapten KW - Linker KW - Antibody drug conjugate KW - ADC KW - Drug-to-antibody ratio KW - DAR KW - Conjugation ratio KW - Conjugation density KW - Carrier load KW - Click reaction KW - Click chemistry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427188 UR - http://www.mdpi.com/2409-9279/1/1/2 DO - https://doi.org/10.3390/mps1010002 SN - 2409-9279 VL - 1 SP - 1 EP - 14 PB - MDPI CY - Basel, Schweiz AN - OPUS4-42718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinmuth-Selzle, K. A1 - Kampf, C. J. A1 - Lucas, K. A1 - Lang-Yona, N. A1 - Fröhlich-Nowoisky, J. A1 - Shiraiwa, M. A1 - Lakey, P. S. J. A1 - Lai, S. A1 - Liu, F. A1 - Kunert, A. T. A1 - Ziegler, K. A1 - Shen, F. A1 - Sgarbanti, R. A1 - Weber, B. A1 - Bellinghausen, I. A1 - Saloga, J. A1 - Weller, Michael G. A1 - Duschl, A. A1 - Schuppan, D. A1 - Pöschl, U. T1 - Air pollution and climate change effects on allergies in the anthropocene: Abundance, interaction, and modification of allergens and adjuvants N2 - Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive. This article provides an overview of physical, chemical and biological interactions between air pollution, climate change, allergens, adjuvants and the immune system, addressing how these interactions may promote the development of allergies. We reviewed and synthesized key findings from atmospheric, climate, and biomedical research. The current state of knowledge, open questions, and future research perspectives are outlined and discussed. The Anthropocene, as the present era of globally pervasive anthropogenic influence on planet Earth and, thus, on the human environment, is characterized by a strong increase of carbon dioxide, ozone, nitrogen oxides, and combustion- or traffic-related particulate matter in the atmosphere. These environmental factors can enhance the abundance and induce chemical modifications of allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions. In particular, air pollutants can act as adjuvants and alter the immunogenicity of allergenic proteins, while climate change affects the atmospheric abundance and human exposure to bioaerosols and aeroallergens. To fully understand and effectively mitigate the adverse effects of air pollution and climate change on allergic diseases, several challenges remain to be resolved. Among these are the identification and quantification of immunochemical reaction pathways involving allergens and adjuvants under relevant environmental and physiological conditions. KW - Allergie KW - Klimaveränderung KW - Luftverschmutzung KW - Partikel KW - Ozon KW - Stickoxide KW - Allergene KW - Adjuvantien KW - PALM KW - DAMP PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404531 DO - https://doi.org/10.1021/acs.est.6b04908 SN - 1520-5851 SN - 0013-936X VL - 51 IS - 8 SP - 4119 EP - 4141 PB - American Chemical Society (ACS) CY - Washington AN - OPUS4-40453 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 - Liu, F. A1 - Lakey, P. S. J. A1 - Berkemeier, T. A1 - Tong, H. A1 - Kunert, A. T. A1 - Meusel, H. A1 - Cheng, Y. A1 - Su, H. A1 - Fröhlich-Nowoisky, J. A1 - Lai, S. A1 - Weller, Michael G. A1 - Shiraiwa, M. A1 - Pöschl, U. A1 - Kampf, C. J. T1 - Atmospheric protein chemistry influenced by anthropogenic air pollutants: nitration and oligomerization upon exposure to ozone and nitrogen dioxide N2 - The allergenic potential of airborne proteins may be enhanced via post-translational modification induced by air pollutants like ozone (O3) and nitrogen dioxide (NO2). The molecular mechanisms and kinetics of the chemical modifications that enhance the allergenicity of proteins, however, are still not fully understood. Here, protein tyrosine nitration and oligomerization upon simultaneous exposure of O3 and NO2 were studied in coated-wall flow-tube and bulk solution experiments under varying atmospherically relevant conditions (5–200 ppb O3, 5–200 ppb NO2, 45–96% RH), using bovine serum albumin as a model protein. Generally, more tyrosine residues were found to react via the nitration pathway than via the oligomerization pathway. Depending on reaction conditions, oligomer mass fractions and nitration degrees were in the ranges of 2.5–25% and 0.5–7%, respectively. The experimental results were well reproduced by the kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB). The extent of nitration and oligomerization strongly depends on relative humidity (RH) due to moisture-induced phase transition of proteins, highlighting the importance of cloud processing conditions for accelerated protein chemistry. Dimeric and nitrated species were major products in the liquid phase, while protein oligomerization was observed to a greater extent for the solid and semi-solid phase states of proteins. Our results show that the rate of both processes was sensitive towards ambient ozone concentration but rather insensitive towards different NO2 levels. An increase of tropospheric ozone concentrations in the Anthropocene may thus promote pro-allergic protein modifications and contribute to the observed increase of allergies over the past decades. KW - Oxidation KW - Nitration KW - Cross-linking KW - Ozone KW - Nitrogen dioxide KW - Dimer KW - Air pollution KW - Diesel KW - Aeroallergens KW - Pollen KW - Tyrosine KW - Nitrotyrosine KW - BSA KW - Albumin PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418482 DO - https://doi.org/10.1039/c7fd00005g SN - 1359-6640 VL - 200 SP - 413 EP - 427 PB - Royal Society of Chemistry CY - London AN - OPUS4-41848 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 - Liu, F. A1 - Lai, S. A1 - Tong, H. A1 - Lakey, P. S. J. A1 - Shiraiwa, M. A1 - Weller, Michael G. A1 - Pöschl, U. A1 - Kampf, C. J. T1 - Release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals N2 - Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals. KW - Peptides KW - Proteins KW - Oxidation KW - Hydroxyl radicals KW - LC-MS KW - Amino acid analysis KW - Bovine serum albumin KW - Ovalbumin KW - Tripeptides KW - Ortho-Phthalaldehyde KW - AAA KW - Degradation KW - Fragmentation KW - Mechanism PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-398714 UR - http://link.springer.com/article/10.1007%2Fs00216-017-0188-y DO - https://doi.org/10.1007/s00216-017-0188-y SN - 1618-2650 SN - 1618-2642 VL - 409 IS - 9 SP - 2411 EP - 2420 PB - Springer CY - Heidelberg AN - OPUS4-39871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seidel, R. A1 - Kraffert, K. A1 - Kabelitz, Anke A1 - Pohl, M.N. A1 - Kraehnert, R. A1 - Emmerling, Franziska A1 - Winter, B. T1 - Detection of the electronic structure of iron-(III)-oxo oligomers forming in aqueous solutions N2 - The nature of the small iron-oxo oligomers in iron-(III) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-Jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl3 aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe3+ monomers. Addition of NaOH initiates Fe3+ hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2–0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and Oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe3+. Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron Peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit Maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the Transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering. KW - Iron-oxo oligomers KW - XPS KW - Electronic structure PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-433468 DO - https://doi.org/10.1039/c7cp06945f SN - 1463-9076 SN - 1463-9084 VL - 19 IS - 48 SP - 32226 EP - 32234 AN - OPUS4-43346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haferkamp, Sebastian A1 - Fischer, Franziska A1 - Kraus, Werner A1 - Emmerling, Franziska T1 - Mechanochemical Knoevenagel condensation investigated in situ N2 - The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. The in situ data indicate that the process is fast and proceeds under a direct conversion. After stopping the milling process, the reaction continues until complete conversion. The continuous and the stopped milling process both result in crystalline products suitable for single crystal X-ray diffraction. KW - Mechanochemistry KW - Ball milling KW - C–C coupling KW - In situ KW - Knoevenagel condensation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425388 DO - https://doi.org/10.3762/bjoc.13.197 VL - 13 SP - 2010 EP - 2014 PB - Beilstein-Institut AN - OPUS4-42538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Nielow, Dustin T1 - Fatigue loading of sandwich shell test specimens with simulated production imperfections and in-situ NDT N2 - A shell test bench was developed at BAM 5.3 which allows for static and fatigue testing of curved fiber-reinforced plastic (FRP) structures, during which in-situ the damage state can be non-destructively inspected by thermography and strain-field measurement techniques. Sandwich shell specimens with typical wind turbine blade manufacturing defects were designed and tested. The tested imperfections show a fairly significant reduction (up to 90%) of the shell test specimens‘ lifetime, depending on the type of imperfection. Using the in-situ NDT methods incorporated in the shell test bench, the location and cycle time of the initial defects and the damage evolution was investigated. T2 - 7. International Conference on Fatigue of Composites CY - Vicenza, Italy DA - 04.06.2018 KW - Fatigue of sandwich shell structures KW - Non-destructive testing KW - Wind turbine blades PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501275 SP - 1 EP - 7 AN - OPUS4-50127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Degradation of AISI 630 exposed to CO2-saturated saline aquifer at ambient pressure and 100 bar N2 - In general high alloyed steels are suitable as pipe steels for carbon capture and storage technology (CCS), because they provide sufficient resistance against the corrosive environment of CO2-saturated saline aquifer which serves as potential CCS-site in Germany. High alloyed martensitic steel AISI 630 has been proven to be sufficient resistant in corrosive environments, e.g. regarding heat, pressure, salinity of the aquifer, CO2-partial pressure), but reveals a distinct corrosion pattern in CCS environment. Therefore coupons of AISI 630 heat treated using usual protocols were kept at T=60 °C and ambient pressure as well as p=100 bar up to 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. AISI 630 precipitates a discontinuous ellipsoidal corrosion layer after being exposed for more than 4000 hours. Best corrosion resistance in the CO2-saturated synthetic aquifer environment phase is achieved via normalizing prior to exposure. In water saturated supercritical CO2 tempering at medium temperatures after hardening gives lowest corrosion rates. Corrosion fatigue via push-pull tests with a series of 30 specimens was evaluated at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). The endurance limit of AISI 630 is reduced by more than 50% when exposed to CCS environment (maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa). KW - Corrosion Fatigue KW - High Cycle Fatigue KW - Steel KW - Ccs KW - Co2-Storage PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503783 DO - https://doi.org/10.22587/jasr.2018.14.6.3 SN - 1819-544X SN - 1816-157X SP - 11 EP - 17 PB - INSInet Publications CY - Faisalabad AN - OPUS4-50378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Puthiyaveettil, N. A1 - Kidangan, R. A1 - Unnikrishnakurup, Sreedhar A1 - Krishnamurthy, C. V. A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Balasubramaniam, K. T1 - Numerical study of laser line thermography for crack detection at high temperature N2 - The detection of cracks before the failure is highly significant when it comes to safety-relevant structures. Crack detection in metallic samples at high surface temperature is one of the challenging situation in manufacturing industries. Laser thermography has already proved its detection capability of surface cracks in metallic samples at room temperature. In this work a continuous wave (CW) laser use to generate a laser, which is using to scan the metal surface with notch. The corresponding heat distribution on the surface monitored using infrared thermal (IR) camera. A simplified 3D model for laser thermography is developed and validated with experimental results. A dedicated image processing algorithm developed to improve the detectability of the cracks. To understand the dependency of surface temperature, laser power, laser scanning speed etc. in defect detection, we carried out parametric studies with our validated model. Here we Report the capability of laser thermography in crack detection at elevated temperature. T2 - 14th Quantitative InfraRed Thermography Conference CY - Berlin, Germany DA - 25.06.2018 KW - Thermal contrast KW - Laser Thermography KW - FEM KW - Surface cracks KW - NDT PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499113 DO - https://doi.org/10.21611/qirt.2018.076 SN - 2371-4085 VL - 2018 SP - 685 EP - 686 AN - OPUS4-49911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nilsson, R. H. A1 - Taylor, A. F. S. A1 - Adams, R. I. A1 - Baschien, C. A1 - Bengtsson-Palme, J. A1 - Cangren, P. A1 - Coleine, C. A1 - Iršėnaitė, R. A1 - Martin-Sanchez, Pedro Maria A1 - Meyer, W. A1 - Oh, S.-Y. A1 - Sampaio, J. P. A1 - Seifert, K. A. A1 - Sklenář, F. A1 - Stubbe, D. A1 - Suh, S.-O. A1 - Summerbell, R. A1 - Svantesson, S. A1 - Unterseher, M. A1 - Visagie, C. M. A1 - Weiss, M. A1 - Woudenberg, J. HC. A1 - Wurzbacher, C. A1 - Van den Wyngaert, S. A1 - Yilmaz, N. A1 - Yurkov, A. A1 - Kõljalg, U. A1 - Abarenkov, K. A1 - Daniel, H.-M. A1 - Glassman, S. I. A1 - Hirooka, H. A1 - Irinyi, L. T1 - Taxonomic annotation of public fungal ITS sequences from the built environment – a report from an April 10–11, 2017 workshop (Aberdeen, UK) N2 - Recent DNA-based studies have shown that the built environment is surprisingly rich in fungi. These indoor fungi – whether transient visitors or more persistent residents – may hold clues to the rising levels of human allergies and other medical and building-related health problems observed globally. The taxo¬nomic identity of these fungi is crucial in such pursuits. Molecular identification of the built mycobiome is no trivial undertaking, however, given the large number of unidentified, misidentified, and technically compromised fungal sequences in public sequence databases. In addition, the sequence metadata required to make informed taxonomic decisions – such as country and host/substrate of collection – are often lacking even from reference and ex-type sequences. Here we report on a taxonomic annotation workshop (April 10–11, 2017) organized at the James Hutton Institute/University of Aberdeen (UK) to facilitate reproducible studies of the built mycobiome. The 32 participants went through public fungal ITS bar¬code sequences related to the built mycobiome for taxonomic and nomenclatural correctness, technical quality, and metadata availability. A total of 19,508 changes – including 4,783 name changes, 14,121 metadata annotations, and the removal of 99 technically compromised sequences – were implemented in the UNITE database for molecular identification of fungi (https://unite.ut.ee/) and shared with a range of other databases and downstream resources. Among the genera that saw the largest number of changes were Penicillium, Talaromyces, Cladosporium, Acremonium, and Alternaria, all of them of significant importance in both culture-based and culture-independent surveys of the built environment. KW - Indoor mycobiome KW - Built environment KW - Molecular identification KW - Fungi KW - Taxonomy KW - Systematics KW - Sequence annotation KW - Metadata KW - Open data PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438949 DO - https://doi.org/10.3897/mycokeys.28.20887 SN - 1314-4049 SN - 1314-4057 VL - 28 SP - 65 EP - 82 PB - Pensoft Publishers CY - Washington, DC AN - OPUS4-43894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hufsky, F. A1 - Ibrahim, B. A1 - Beer, M. A1 - Deng, L. A1 - Le Mercier, P. A1 - McMahon, Dino Peter A1 - Palmarini, M. A1 - Thiel, V. A1 - Marz, M. T1 - Virologists—Heroes need weapons N2 - Virologists. You might know a couple of them, but unless you are a virologist yourself, the probability that you have collaborated with one in the past is low. The community is relatively small, but they pack a heavy punch and are expected to play a leading role in the research into pathogens that lies ahead. You may ask why we think virologists are our future. Suffice it to say that it is not just because they have invented technologies that belong to the space age, including use of viruses as vehicles to shuttle genes into cells[1], organic nanoparticles with specific tools attached to their surfaces to get inside target cells[2], and using genetically modified viruses as therapies to fight against cancer[3]. Did you know that virologists currently only know of about 3,200 viral species but that more than 320,000 mammal-associated viruses[4] are thought to await discovery? Just think about the viruses hidden in the Arctic ice[5] or in the insects and other animals from once cut-off regions in the world, which now face ever-increasing human exposure[6]. But a heroic (as well as an apocalyptic) role for virologists may also be on the horizon, as the adoption of phage therapy may, in the future, be used to control harmful bacteria when antibiotics fail KW - Virology KW - Bioinformatics PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442402 DO - https://doi.org/10.1371/journal.ppat.1006771 SN - 1553-7366 SN - 1553-7374 VL - 14 IS - 2 SP - Article e1006771, 1 EP - 3 PB - Public Library of Science CY - Lawrence, Kan. AN - OPUS4-44240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S. A1 - De Beats, P. A1 - Sukumaran, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias A1 - Vleugels, J. T1 - Effect of carbon content on the microstructure and mechanical properties of NbC-Ni based cermets N2 - The aim of this work was to correlate the overall carbon contents in NbC-Ni, NbC-Ni-VC and NbC-Ni-Mo starting powders with the resulting microstructure, hardness, and fracture toughness of Ni-bonded NbC cermets. KW - Niobium carbide KW - Cermet KW - Hardmetal KW - Liquid phase sintering KW - Carbon KW - Hardness PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444608 DO - https://doi.org/10.3390/met8030178 SN - 2075-4701 VL - 8 IS - 3 SP - Article 178, 1 EP - 13 PB - MDPI AN - OPUS4-44460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Örnek, C. A1 - Léonard, Fabien A1 - McDonald, S. A1 - Prajapati, A A1 - Withers, P. J. A1 - Engelberg, D. T1 - Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires N2 - Corrosion rates of strained grade UNS S32202 (2202) and UNS S32205 (2205) duplex stainless steel wires have been measured, in situ, using time-lapse X-ray computed tomography. Exposures to chloride-containing (MgCl2) atmospheric environments at 50 °C (12–15 M Cl− and pH ~5) with different mechanical elastic and elastic/plastic loads were carried out over a period of 21 months. The corrosion rates for grade 2202 increased over time, showing selective dissolution with shallow corrosion sites, coalescing along the surface of the wire. Corrosion rates of grade 2205 decreased over time, showing both selective and pitting corrosion with more localised attack, growing preferentially in depth. The nucleation of stress corrosion cracking was observed in both wires. KW - X-ray computed tomography KW - Time-lapse X-ray computed tomography PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444153 UR - https://www.nature.com/articles/s41529-018-0030-9 DO - https://doi.org/10.1038/s41529-018-0030-9 SN - 2397-2106 VL - 2 SP - Article 10, 1 EP - 15 PB - Nature CY - London AN - OPUS4-44415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laux, P. A1 - Tentschert, J. A1 - Riebeling, Ch. A1 - Braeuning, A. A1 - Creutzenberg, O. A1 - Epp, A. A1 - Fessard, V. A1 - Haas, K.-H. A1 - Haase, A. A1 - Hund-Rinke, K. A1 - Jakubowski, Norbert A1 - Kearns, P. A1 - Lampen, A. A1 - Rauscher, H. A1 - Schoonjans, R. A1 - Störmer, A. A1 - Thielmann, A. A1 - Mühle, U. A1 - Luch, A. T1 - Nanomaterials: certain aspects of application, risk assessment and risk communication N2 - Development and market introduction of new nanomaterials trigger the need for an adequate risk assessment of such products alongside suitable risk communication measures. Current application of classical and new nanomaterials is analyzed in context of regulatory requirements and standardization for chemicals, food and consumer products. The challenges of nanomaterial characterization as the main bottleneck of risk assessment and regulation are presented. In some areas, e.g., quantification of nanomaterials within complex matrices, the establishment and adaptation of analytical techniques such as laser ablation inductively coupled plasma mass spectrometry and others are potentially suited to meet the requirements. As an example, we here provide an approach for the reliable characterization of human exposure to nanomaterials resulting from food packaging. Furthermore, results of nanomaterial toxicity and ecotoxicity testing are discussed, with concluding key criteria such as solubility and fiber rigidity as important parameters to be considered in material development and regulation. Although an analysis of the public opinion has revealed a distinguished rating depending on the particular field of application, a rather positive perception of nanotechnology could be ascertained for the German public in general. An improvement of material characterization in both toxicological testing as well as end-product control was concluded as being the main obstacle to ensure not only safe use of materials, but also wide acceptance of this and any novel technology in the general public. KW - Nanomaterials KW - Toxicity KW - Ecotoxicity KW - Standardization KW - Exposure PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441096 DO - https://doi.org/10.1007/s00204-017-2144-1 VL - 92 IS - 1 SP - 121 EP - 141 PB - Springer AN - OPUS4-44109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, S. A1 - López-Serrano, Ana A1 - Mitze, H. A1 - Jakubowski, Norbert A1 - Schwerdtle, T. T1 - Single-cell analysis by ICP-MS/MS as a fast tool for cellular bioavailability studies of arsenite N2 - Single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS) has become a powerful and fast tool to evaluate the elemental composition at a single-cell level. In this study, the cellular bioavailability of arsenite (incubation of 25 and 50 μM for 0-48 h) has been successfully assessed by SC-ICP-MS/MS for the first time directly after re-suspending the cells in water. This procedure avoids the normally arising cell membrane permeabilization caused by cell fixation methods (e.g. methanol fixation). The reliability and feasibility of this SC-ICP-MS/MS approach with a limit of detection of 0.35 fg per cell was validated by conventional bulk ICP-MS/MS analysis after cell digestion and parallel measurement of sulfur and phosphorus. KW - Single-cell analysis KW - ICP-MS/MS KW - Arsenite PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441105 DO - https://doi.org/10.1039/c7mt00285h SN - 1756-5901 VL - 10 IS - 1 SP - 73 EP - 76 PB - RSC Publ. CY - Cambridge AN - OPUS4-44110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Topolniak, Ievgeniia A1 - Pötschke, Samuel A1 - Krebber, Katerina T1 - Solution-mediated cladding doping of commercial polymer optical fibers N2 - Solution doping of commercial polymethyl methacrylate (PMMA) polymer optical fibers (POFs) is presented as a novel approach for preparation of custom cladding-doped POFs (CD-POFs). The presented method is based on a solution-mediated diffusion of dopant molecules into the fiber cladding upon soaking of POFs in a methanol-dopant solution. The method was tested on three different commercial POFs using Rhodamine B as a fluorescent dopant. The dynamics of the diffusion process was studied in order to optimize the doping procedure in terms of selection of the most suitable POF, doping time and conditions. Using the optimized procedure, longer segment of fluorescent CD-POF was prepared and its performance was characterized. Fiber’s potential for sensing and illumination applications was demonstrated and discussed. The proposed method represents a simple and cheap way for fabrication of custom, short to medium length CD-POFs with various dopants. KW - Polymer optical fiber KW - Solution doping KW - Polymethyl methacrylate KW - Rhodamine B KW - Dye-doped fiber KW - Fluorescent optical fiber PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441045 DO - https://doi.org/10.1016/j.yofte.2018.02.008 SN - 1068-5200 SN - 1095-9912 VL - 41 SP - 227 EP - 234 PB - Elsevier Inc. AN - OPUS4-44104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lasri, J. A1 - Chulvi, Katherine A1 - Eltayeb, N. E. T1 - Crystal structures of (E)-1-naphthaldehyde oxime and (E)-phenanthrene-9-carbaldehyde oxime N2 - The aldoximes C11H9NO (I) and C15H11NO (II), synthesized in ca 90%yield, by treatment of 1-naphthaldehyde or phenanthrene-9-carbaldehyde, respectively, with hydroxylamine hydrochloride and sodium carbonate, have been characterized by IR, 1H, 13C and DEPT-135 NMR spectroscopies, and also by singlecrystal X-ray diffraction analysis. The molecules of (I) and (II) are conformationally similar, with the aldoxime substituent groups lying outside the planes of the naphthalene or phenanthrene rings, forming dihedral angles with them of 23.9 (4) and 27.9 (6)°, respectively. The crystal structures of both (I) and (II) are similar with a single intermolecular O—H...N hydrogenbonding interaction, giving rise to the formation of one-dimensional polymeric chains extending along the 21 (b) screw axes in each. KW - Crystal structure KW - Aromatic aldehydes KW - E-aldoximes KW - Hydrogen bonding PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-443351 DO - https://doi.org/10.1107/S2056989018002116 SN - 2056-9890 VL - 74 SP - 332 EP - 336 PB - International Union of Crystallography CY - Chester AN - OPUS4-44335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hollamby, M. J. A1 - Smith, C. F. A1 - Britton, M. M. A1 - Danks, A. E. A1 - Schnepp, Z. A1 - Grillo, I. A1 - Pauw, Brian Richard A1 - Kishimura, A. A1 - Nakanishi, T. T1 - The aggregation of an alkyl–C60 derivative as a function of concentration, temperature and solvent type N2 - Contrast-variation small-angle neutron scattering (CV-SANS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) measurements of diffusion and isothermal titration calorimetry (ITC) are used to gain insight into the aggregation of an alkyl–C60 derivative, molecule 1, in n-hexane, n-decane and toluene as a function of concentration and temperature. Results point to an associative mechanism of aggregation similar to other commonly associating molecules, including non-ionic surfactants or asphaltenes in non-aqueous solvents. Little aggregation is detected in toluene, but small micelle-like structures form in n-alkane solvents, which have a C60-rich core and alkyl-rich shell. The greatest aggregation extent is found in n-hexane, and at 0.1 M the micelles of 1 comprise around 6 molecules at 25 °C. These micelles become smaller when the concentration is lowered, or if the solvent is changed to n-decane. The solution structure is also affected by temperature, with a slightly larger aggregation extent at 10 °C than at 25 °C. At higher concentrations, for example in solutions of 1 above 0.3 M in n-decane, a bicontinuous network becomes apparent. Overall, these findings aid our understanding of the factors driving the assembly of alkyl–π-conjugated hydrophobic amphiphiles such as 1 in solution and thereby represent a step towards the ultimate goal of exploiting this phenomenon to form materials with well-defined order. KW - Complex Molecular Systems KW - Supramolecules KW - Scattering PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442977 DO - https://doi.org/10.1039/C7CP06348B VL - 20 IS - 5 SP - 3773 EP - 3380 PB - RSC AN - OPUS4-44297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hinrichs, R. A1 - Zen Vasconcellos, M.A. A1 - Österle, Werner A1 - Prietzel, C. T1 - Amorphization of graphite flakes in gray cast iron under tribological load N2 - A gray cast iron disc, which had been submitted to a heavy duty automotive brake test, was examined with energy filtered transmission electron microscopy. A graphite flake in a convenient angular position showed the shear interaction of graphite layers with the iron matrix in nano-scale resolution. Atomic layers of graphite were wedged into the ferritic bulk, allowing the entrance of oxygen and the subsequent formation of magnetite. The exfoliated few-layer graphene batches deformed heavily when forced into the matrix. When Raman spectra from the disc surface, which show distinctive carbonaceous bands, were compared with Raman spectra from graphite subjected to deformation in a shaker mill with different milling times, it could be seen that the shear stress on the brake surface was much more effective to induce disorder than the milling, where compressive and impact forces had been additionally exerted on the sample. During shear load the high anisotropy of elastic modulus in the graphite crystalline structure and the low adhesion between graphite basal planes allowed the exfoliation of wrinkled few-layer grapheme batches, causing the formation of more defect related Raman bands than the mechanical stress during high-energy milling. KW - Graphite KW - Shear load KW - Amorphization KW - EFTEM KW - Raman spectroscopy PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469227 DO - https://doi.org/10.1590/1980-5373-MR-2017-1000 SN - 1516-1439 SN - 1980-5373 VL - 21 IS - 4 SP - e20171000, 1 EP - 6 PB - Universidade Federal de São Carlos CY - São Carlos AN - OPUS4-46922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wack, Yannick A1 - Heckel, Thomas A1 - Boehm, Rainer A1 - Brackrock, Daniel T1 - Simulation der Schallausbreitung in Eisenbahnschienen mit FEM und SAM N2 - Die Simulation von Ultraschallausbreitung ist ein wesentliches Hilfsmittel zur Optimierung von Prüfanordnungen und wird zunehmend in der Prüfvorbereitung eingesetzt. Eisenbahnschienen sind Bauteile mit komplexer Geometrie und im eingebauten Zustand eingeschränkter Zugänglichkeit. Bei der Prüfung im Feld entstehen aus der Schienengeometrie komplexe Echosignale mit Formanzeigen, die schwer zu interpretieren sind. Für das bessere Verständnis der Schallausbreitung in der Eisenbahnschiene wird diese in einem ersten Schritt mit Hilfe verschiedener Ansätze modelliert. Hierbei werden Finite Elemente Methoden und semi-analytischen Modelle verwendet. In einem zweiten Schritt werden die Ergebnisse der Simulationsmodelle einander gegenübergestellt und mit Messungen an realen Schienen verglichen. Ziel dieser Untersuchungen ist die Validierung von Simulationsverfahren mit Hilfe von Messdatensätzen und Überprüfung der Anwendbarkeit bei der Bewertung von Ergebnissen der Schienenprüfung. T2 - DGZfP-Jahrestagung 2018 CY - Leibzig, Gemany DA - 07.05.2018 KW - Ultraschall KW - FEM KW - Eisenbahn KW - Simulation KW - SAM PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474585 SP - Poster 4 - 1 EP - 5 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-47458 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeise, I. A1 - Heiner, Z. A1 - Holz, S. A1 - Joester, Maike A1 - Buttner, C. A1 - Kneipp, Janina T1 - Raman imaging of plant cell walls in sections of cucumis sativus N2 - Raman microspectra combine information on chemical composition of plant tissues with spatial information. The contributions from the building blocks of the cell walls in the Raman spectra of plant tissues can vary in the microscopic sub-structures of the tissue. Here, we discuss the analysis of 55 Raman maps of root, stem, and leaf tissues of Cucumis sativus, using different spectral contributions from cellulose and lignin in both univariate and multivariate imaging methods. Imaging based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicates different substructures in the xylem cell walls of the different tissues. Using specific signals from the cell wall spectra, analysis of the whole set of different tissue sections based on the Raman images reveals differences in xylem tissue morphology. Due to the specifics of excitation of the Raman spectra in the visible wavelength range (532 nm), which is, e.g., in resonance with carotenoid species, effects of photobleaching and the possibility of exploiting depletion difference spectra for molecular characterization in Raman imaging of plants are discussed. The reported results provide both, specific information on the molecular composition of cucumber tissue Raman spectra, and general directions for future imaging studies in plant tissues. KW - Raman KW - Imaging KW - Pants PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474610 DO - https://doi.org/10.3390/plants7010007 SN - 2223-7747 VL - 7 IS - 1 SP - 7, 1 EP - 16 PB - MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND AN - OPUS4-47461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Scharf, Holger A1 - Lkhagvasuren, B. A1 - Oyuntungalag, U. A1 - Rausch, J. T1 - Certified reference material for determination of total cyanide in soil [BAM-U116/CGL306] N2 - CRM (Certified Reference Material) BAM-U116/CGL306 “Cyanide in soil” was produced within a framework of cooperation between CGL (Central Geological Laboratory) of Mongolia and Federal Institute for Materials Research and Testing (BAM) of Germany in 2013-2017. The CRM BAM-U116/CGL306 represents a mixture of a sandy soil collected from a contaminated former gasworks area in the Berlin region (Germany) and an unpolluted sandy soil from Nalaikh region (Mongolia). The bulk candidate material for this reference material was prepared at CGL CRM Laboratory exclusively destined to the preparation of reference materials and equipped with modern technical equipment. Homogeneity, stability and shelf life were studied in full compliance with ISO Guide 35. The CRM was evaluated as sufficiently homogeneous. Statistical evaluation of certification analysis was software packages SoftCRM and ProLab Plus. Certified value of total cyanide of the CRM is 12.0 mg/kg and expanded uncertainty was assigned as 0.8 mg/kg. The intended purpose of this material is the verification of analytical results obtained for the mass fraction of total cyanide in soils and soil-like materials applying the standardized procedure ISO 11262:2011. As any reference material, it can also be used for routine performance checks (quality control charts) or validation studies. KW - CRM KW - Cyanide in soil KW - Total cyanide PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469694 DO - https://doi.org/10.17265/2162-5263/2018.04.004 SP - 149 EP - 161 PB - David Publishing AN - OPUS4-46969 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ringleb, F. A1 - Andree, Stefan A1 - Heidmann, B. A1 - Bonse, Jörn A1 - Eylers, K. A1 - Ernst, O. A1 - Boeck, T. A1 - Schmid, M. A1 - Krüger, Jörg T1 - Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics N2 - Micro-concentrator solar cells offer an attractive way to further enhance the efficiency of planar-cell technologies while saving absorber material. Here, two laser-based bottom-up processes for the fabrication of regular arrays of CuInSe2 and Cu(In,Ga)Se2 microabsorber islands are presented, namely one approach based on nucleation and one based on laser-induced forward transfer. Additionally, a procedure for processing these microabsorbers to functioning micro solar cells connected in parallel is demonstrated. The resulting cells show up to 2.9% efficiency and a significant efficiency enhancement under concentrated Illumination. KW - Chalcopyrite KW - Femtosecond laser patterning KW - Laser-induced forward transfer KW - Micro-concentrator solar cell KW - Photovoltaics PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470026 DO - https://doi.org/10.3762/bjnano.9.281 SN - 2190-4286 VL - 9 SP - 3025 EP - 3038 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-47002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waske, Anja A1 - Dutta, B. A1 - Teichert, N. A1 - Weise, B. A1 - Shayanfar, N. A1 - Becker, A. A1 - Hütten, A. A1 - Hickel, T. T1 - Coupling Phenomena in Magnetocaloric Materials N2 - Strong coupling effects in magnetocaloric materials are the key factor to achieve a large magnetic entropy change. Combining insights from experiments and ab initio calculations, we review relevant coupling phenomena, including atomic coupling, stress coupling, and magnetostatic coupling. For the investigations on atomic coupling, we have used Heusler compounds as a flexible model system. Stress coupling occurs in first‐order magnetocaloric materials, which exhibit a structural transformation or volume change together with the magnetic transition. Magnetostatic coupling has been experimentally demonstrated in magnetocaloric particles and fragment ensembles. Based on the achieved insights, we have demonstrated that the materials properties can be tailored to achieve optimized magnetocaloric performance for cooling applications. KW - Ab initio calculations KW - Magneto-structural transition KW - Magnetocaloric materials KW - Ferroic cooling KW - Heusler alloys PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473045 DO - https://doi.org/10.1002/ente.201800163 VL - 6 IS - 8 SP - 1429 EP - 1447 PB - Wiley AN - OPUS4-47304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Vogel, Justus A1 - Zhang, F. A1 - Long, N.X. A1 - Nguyen, T.P. T1 - Visibility of Image Quality Indicators (IQI) by Human Observers in Digital Radiography in Dependence on Measured MTFs and Noise Power Spectra N2 - Digital radiographic images were analysed to predict the visibility of image quality indicators (IQI), based on normalized noise power spectra (NNPP) and modulation transfer function (MTF) measurements. The fixed pattern noise of some digital detectors result in different noise spectra, which influence the visibility of different IQIs, depending on the hole diameter. Studies, based on measurement of basic spatial resolution and contrast to noise ratio were performed together with presampled MTF measurements and the NNPS in dependence on the spatial frequency. Plate hole IQIs, step hole IQIs, and equivalent penetrameter sensitivity (EPS) IQIs based on ASTM E 746 were measured to verify the influence of the different parameters. Modelling of digital images was used to verify the applied numeric tools. A study has been performed for imaging plates and digital detector arrays to analyse differences. Formulas for the prediction of the visibility functions for hole type IQIs are derived. In consequence the standards for characterization and classification of computed radiography (ASTM E 2446) and radiography with DDAs (ASTM E 2597) need to be revised. T2 - 12th ECNDT 2018 CY - Gothenburg, Sweden DA - 11.06.2018 KW - Image evaluation KW - Computed radiography (CR) KW - Digital Detector Array (DDA) KW - Detail detection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473486 UR - www.ndt.net/?id=22967 SN - 1435-4934 VL - 23 IS - 8 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-47348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Zhang, F. A1 - Long, N.X. A1 - Phong, N. T1 - Essentielle Parameter zur numerischen Abschätzung der Sichtbarkeit von Bildgüteprüfkörpern in der digitalen Radiographie N2 - Die Voraussetzungen für die Vorhersage der Sichtbarkeit von Bildgüteprüfkörpern (BPK) wurden seit Beginn der kommerziellen Anwendung der technischen Radiographie diskutiert und in diversen nationalen und internationalen Standards festgeschrieben. Diese Fragen werden nach Einführung der digitalen Radiographie und der CT wieder neu diskutiert. Draht BPKs wurden in Deutschland seit 1935 (DIN 1915: 1935) und später in den meisten europäischen Ländern benutzt. In den USA und Frankreich wurden vorzugsweise BPKs mit Löchern verwendet (ASTM E 1025 seit 1984 oder E 1742 seit 1992 bzw. die Vorgängernorm MIL STD-543 seit 1962). Jetzt werden auch die Umrechnungsnormen zur Erkennbarkeit von Draht zu Loch-BPKs in Frage gestellt. ISO 19232-3, der französische RCCM-Kode einerseits und ASTM E 747 und ASME BPVC Section V Tab. T-276 andererseits unterscheiden sich erheblich bei den Anforderungen im Bereich hoher Wandstärken (Hochenergieradiographie). Untersuchungen dazu werden vorgestellt. Mit Einführung der digitalen Detektoren ändern sich auch die Rauschspektren. Durch die Herstellung werden insbesondere bei Speicherfolien "Rauschmuster" eingeprägt, die bei hohen Belichtungsdosen sichtbar werden. Diese veränderten Rauschspektren ergeben auch veränderte Erkennungsparameter für menschliche Bildauswerter. Hierzu wurden an ausgewählten Detektoren MTFs (presampled) und normierte Rauschspektren gemessen. Erweiterte Erkennbarkeits-Formeln zur Vorhersage der Sichtbarkeit von BPKs für Bildauswerter und erste Ergebnisse werden vorgestellt. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Image quality KW - Computed radiography (CR) KW - Digital Detector Array (DDA), KW - Sichtbarkeit von Anzeigen PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473496 UR - www.ndt.net/?id=23069 VL - 2018 SP - 1 EP - 14 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-47349 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brückner, B. A1 - Zscherpel, Uwe T1 - Spektroskopie gepulster Röntgenquellen N2 - Spektren von gepulsten Röntgenquellen wie Blitzröhren, Linearbeschleuniger (LINACs) oder Betatrons lassen sich in der Literatur nicht finden. Eine gängige Lehrmeinung ist, dass sich solche Spektren nicht messen lassen. Deshalb wurden in Zusammenarbeit mit der Goethe-Universität Frankfurt und neuester Messtechnik diese Problematik untersucht. Es wurde ein CeBr3-Szintillator-Kristall mit einem klassischen Photoelektronenvervielfacher (PMT) und einer analogen Übertragungskette verwendet, der über Stunden Integrationszeit nur einen sehr geringen Untergrund detektiert. Als kritischter Punkt stellte sich die geeignete Kollimierung von Quelle und Detektor bei möglichst großem Abstand heraus. Zu diesem Zweck wurde das verwendete 7 MeV-Betatron in einen 3t-Bleibunker betrieben, der ein Austrittsloch von 1 mm für die erzeugte Röntgenstrahlung besaß. Der Detektor wurde mit einem Densimet-Zylinder abgeschirmt. Damit konnte die Bedingung für die Spektroskopie gepulster Quellen erreicht werden: pro Puls darf nur 1 Photon den Detektorkristall erreichen, damit ohne Pile-up seine Energie vermessen werden kann. Trotz schnellster Elektronik war es nicht möglich, mehere Photonen pro Röntgenpuls (beim Betatron ca. 1 Mikrosekunde) spektral richtig aufzulösen. Die gemessenen Spektren zeigen die erwartete Form, wie sie z.B. mit aRTist simuliert werden können. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Spektroskopie KW - Betatron KW - Röntgenblitzröhre PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473505 SP - 1 EP - 2 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-47350 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brzeska, J. A1 - Elert, Anna Maria A1 - Morawska, M. A1 - Sikorska, W. A1 - Kowalczuk, M. A1 - Rutkowska, M. T1 - Branched Polyurethanes Based on Synthetic Polyhydroxybutyrate with Tunable Structure and Properties N2 - Branched, aliphatic polyurethanes (PURs) were synthesized and compared to linear analogues. The influence of polycaprolactonetriol and synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments on structure, thermal and sorptive properties of PURs was determined. Using FTIR and Raman spectroscopies it was found that increasing the R,S-PHB amount in the structure of branched PURs reduced a tendency of urethane groups to hydrogen bonding. Melting enthalpies (on DSC thermograms) of both soft and hard segments of linear PURs were higher than branched PURs, suggesting that linear PURs were more crystalline. Oil sorption by samples of linear and branched PURs, containing only polycaprolactone chains in soft segments, was higher than in the case of samples with R,S-PHB in their structure. Branched PUR without R,S-PHB absorbed the highest amount of oil. Introducing R,S-PHB into the PUR structure increased water sorption. Thus, by operating the number of branching and the amount of poly([R,S]-3-hydroxybutyrate) in soft segments thermal and sorptive properties of aliphatic PURs could be controlled. KW - IR KW - Polyurethane KW - PUR KW - RAMAN PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457087 DO - https://doi.org/10.3390/polym10080826 VL - 10 IS - 8 SP - 826, 1 EP - 12 PB - MDPI AN - OPUS4-45708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schreier, Andy A1 - Wosniok, Aleksander A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - Humidity-induced Brillouin frequency shift in perfluorinated polymer optical fibers N2 - We report, to our knowledge, for the first time on humidity-induced Brillouin frequency shifts in perfluorinated graded index polymer optical fibers. A linear relation between Brillouin frequency shift and humidity was observed. Furthermore, the humidity coefficient of the Brillouin frequency shift is demonstrated to be a function of temperature (-107 to -64 kHz/%r.h. or -426 to -49 kHz m3/g in the range of 20 to 60 °C). An analytical description proves temperature and humidity as two mutually independent effects on the Brillouin frequency shift. KW - Brillouin KW - Polymer optical fibre KW - Humidity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457165 DO - https://doi.org/10.1364/OE.26.022307 SN - 1094-4087 VL - 26 IS - 17 SP - 22307 EP - 22314 PB - Optical Society of America AN - OPUS4-45716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Metzsch-Zilligen, E. A1 - Großhauser, M. A1 - Pfaendner, R. A1 - Schartel, Bernhard T1 - Rapid mass calorimeter as a high-throughput screening method for the development of flame-retarded TPU N2 - The rapid mass calorimeter (RMC) was used as a screening tool based on accelerated fire testing to assess flame-retarded thermoplastic polyurethane (TPU). The reliability of RMC results was proven with the cone calorimeter as reference fire test. The influence of melamine cyanurate (MC) concentration on the fire performance of TPU was investigated, along with some flame-retardant combinations such as MC with aluminium diethylphosphinate (AlPi), aluminium trihydrate (ATH), and melamine polyphosphate (MPP). The two-stage burning behaviour of TPU was investigated in detail; the first stage corresponds mainly to the hard segments' decomposition and has a much lower effective heat of combustion (EHC) than the second stage, in which mainly the soft segments decompose and an intensive liquid pool fire is observed in the cone calorimeter set-up. In addition to fire testing with the cone calorimeter, RMC, and UL 94 flammability tests, the decomposition of the materials was investigated using thermogravimetric analysis coupled with infrared spectrometry (TGeFTIR). TPU/MC/AlPi shows the most promising results, achieving V-0 classification in UL 94 and reducing the extreme peak heat release rate (PHRR) of the liquid pool fire from 3154 kW/m2 to 635 kW/m2. Using MC/AlPi/MPP enhances the latter PHRR reduction further. The decomposition products identified in the gas phase via TGeFTIR reveal specific MCeAlPi eMPP interactions, as they differ from products seen in systems with MC/AlPi or MC/MPP. Correlations between RMC and cone calorimeter results were examined and presented in the final part of the paper. Several characteristics correlate strongly, pointing out that RMC is a reliable high-throughput fire testing method to screen multicomponent flame-retardant solutions in TPU. KW - Thermoplastic polyurethane KW - Flame retardancy KW - Rapid mass calorimeter KW - High throughput screening PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456982 SN - 0141-3910 SN - 1873-2321 VL - 156 SP - 43 EP - 58 PB - Elsevier Ltd. AN - OPUS4-45698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Velencoso, M. M. A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - Molecular firefighting – How modern phosphorus chemistry can help solve the challenge of flame retardancy N2 - The ubiquity of polymeric materials in daily life Comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flameretarding polymeric materials. Phosphorus-based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus-based flame-retardants from renewable sources. KW - Flame retardant KW - Phosphorus KW - Halogen-free PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457009 DO - https://doi.org/10.1002/anie.201711735 SN - 1433-7851 SN - 1521-3773 VL - 57 IS - 33 SP - 10450 EP - 10467 PB - Wiley VHC AN - OPUS4-45700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Otremba, Frank A1 - Romero-Navarrete, José A. A1 - Lozano Guzmán, A. A. T1 - Modelling of a Partially Loaded Road Tanker during a Braking-in-a-Turn Maneuver N2 - This paper describes a theoretical model to simulate the effects of a sloshing cargo on the safety performance of a vehicle that performs a braking-in-a-turn maneuver when travels at a partial fill level. The fundamental assumption of the model consists of the superposition of the effects of two simplified mechanical-analogy models that represent a liquid cargo on a vehicle, including one for the roll motion and another one for the pitch motion. The distinctive characteristics of the mechanical models, however, is that they are based upon a validated formulation to establish the properties of the pendulum (length). The results suggest a small effect of the sloshing cargo on the braking efficiency of the cargo, while the load transfer is moderately affected. However, such results should be put into a perspective, according to which such small variations can represent the avoidance of a rear-end crash or a rollover. In this respect, a specialized ABS system could be considered to improve the performance of such kind of vehicles when performing such maneuvers. Validation of the proposed methodology should be performed as a continuation of this research effort. KW - ABS KW - Braking-in-a-turn maneuver KW - Cargo sloshing KW - Road tankers KW - Load transfer KW - Simulation KW - Turning maneuvers PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456908 DO - https://doi.org/10.3390/act7030045 VL - 7 IS - 45 SP - 1 EP - 14 PB - MDPI CY - Basel AN - OPUS4-45690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Davis, Hannah E. A1 - Meconcelli, Stefania A1 - Radek, R. A1 - McMahon, Dino Peter T1 - Termites shape their collective behavioural response based on stage of infection N2 - Social insects employ a range of behaviours to protect their colonies against disease, but little is known about how such collective behaviours are orchestrated. This is especially true for the social Blattodea (termites). We developed an experimental approach that allowed us to explore how the social response to disease is co-ordinated by multistep host-pathogen interactions. We infected the eastern subterranean termite Reticulitermes flavipes with the entomopathogenic fungus Metarhizium anisopliae, and then, at different stages of infection, reintroduced them to healthy nestmates and recorded behavioural responses. As expected, termites groomed pathogen-exposed individuals significantly more than controls; however, grooming was significantly elevated after fungal germination than before, demonstrating the importance of fungal status to hygienic behaviour. Significantly, we found that cannibalism became prevalent only after exposed termites became visibly ill, highlighting the importance of host condition as a cue for social hygienic behaviour. Our study reveals the presence of a coordinated social response to disease that depends on stage of infection. Specifically, we show how the host may play a key role in triggering its own sacrifice. Sacrificial self-flagging has been observed in other social insects: our results demonstrate that termites have independently evolved to both recognize and destructively respond to sickness. KW - Social KW - Immunity KW - Cannibalism KW - Entomopathogen PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463239 DO - https://doi.org/10.1038/s41598-018-32721-7 SN - 2045-2322 VL - 8 SP - 14433, 1 EP - 10 PB - Nature CY - London AN - OPUS4-46323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertovic, Marija T1 - Assessing and Treating Risks in Mechanised NDT: A Human Factors Study N2 - Reliability of NDT is affected by human factors, which have thus far received the least amount of attention in the reliability assessments. With increased use of automation, in terms of mechanised testing (automation-assisted inspection and the corresponding evaluation of data), higher reliability standards are believed to have been achieved. However, human inspectors, and thus human factors, still play an important role throughout this process and the risks involved in this application are unknown. The aim of this study was to explore for the first time the risks associated with mechanised NDT and find ways of mitigating their effects on the inspection performance. Hence, the objectives were to identify and Analyse potential risks in mechanised NDT and devise measures against them. To address those objectives, a risk assessment in form of a Failure Modes and Effects Analysis (FMEA) was conducted. This analysis revealed potential for failure during both the acquisition and evaluation of NDT data that could be assigned to human, technology, and organisation. Since the existing preventive measures were judged to be insufficient to defend the system from identified failures, new preventive measures were suggested. KW - NDT KW - Human factors KW - Risk assessment KW - FMEA KW - Reliability KW - Human error PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463325 SN - 1616-069X IS - 161 SP - 52 EP - 62 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-46332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ibrahim, B. A1 - Arkhipova, K. A1 - Andeweg, A.C. A1 - Posada-Céspedes, S. A1 - Enault, F. A1 - Gruber, A. A1 - Koonin, E.V. A1 - Kupczok, A. A1 - Lemey, P. A1 - McHardy, A.C. A1 - McMahon, Dino Peter A1 - Pickett, B.E. A1 - Robertson, D.L. A1 - Scheuermann, R.H. A1 - Zhernakova, A. A1 - Zwart, M.P. A1 - Schönhuth, A. A1 - Dutilh, B.E. A1 - Marz, M. T1 - Bioinformatics meets virology: The European virus bioinformatics center's second annual meeting N2 - The Second Annual Meeting of the European Virus Bioinformatics Center (EVBC), held in Utrecht, Netherlands, focused on computational approaches in virology, with topics including (but not limited to) virus discovery, diagnostics, (meta-)genomics, modeling, epidemiology, molecular structure, evolution, and viral ecology. The goals of the Second Annual Meeting were threefold: (i) to bring together virologists and bioinformaticians from across the academic, industrial, professional, and training sectors to share best practice; (ii) to provide a meaningful and interactive scientific environment to promote discussion and collaboration between students, postdoctoral fellows, and both new and established investigators; (iii) to inspire and suggest new research directions and questions. Approximately 120 researchers from around the world attended the Second Annual Meeting of the EVBC this year, including 15 renowned international speakers. This report presents an overview of new developments and novel research findings that emerged during the meeting. KW - Bioinformatics KW - Software KW - Virology KW - Viruses PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458814 DO - https://doi.org/10.3390/v10050256 SN - 1999-4915 VL - 10 IS - 5 SP - 256, 1 EP - 19 PB - MDPI AN - OPUS4-45881 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waske, Anja A1 - Dutta, B. A1 - Teichert, N. A1 - Weise, B. A1 - Shayanfar, N. A1 - Becker, A. A1 - Hütten, A. A1 - Hickel, T. T1 - Coupling Phenomena in Magnetocaloric Materials N2 - Strong coupling effects in magnetocaloric materials are the key factor to achieve a large magnetic entropy change. Combining insights from experiments and ab initio calculations, we review relevant coupling phenomena, including atomic coupling, stress coupling, and magnetostatic coupling. For the investigations on atomic coupling, we have used Heusler compounds as a flexible model system. Stress coupling occurs in first‐order magnetocaloric materials, which exhibit a structural transformation or volume change together with the magnetic transition. Magnetostatic coupling has been experimentally demonstrated in magnetocaloric particles and fragment ensembles. Based on the achieved insights, we have demonstrated that the materials properties can be tailored to achieve optimized magnetocaloric performance for cooling applications. KW - Epitaxial thin films KW - Coupling KW - Atomic Scale KW - Stoichiometric phases KW - Multilaysers KW - Stress Coupling KW - Surface defects PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458856 DO - https://doi.org/10.1002/ente.201800163 VL - 6 IS - 8 SP - 1429 EP - 1447 PB - Wiley-VCH AN - OPUS4-45885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bente, Klaas T1 - The thermoacoustic effect and its application in air-coupled testing of composite structures N2 - Airborne ultrasonic testing of lightweight, structured composite materials enables fast and contact-free non-destructive testing in aerospace and avoids material degradation due to contact with a coupling liquid. Established resonant air-coupled transducers consist of piezocomposite materials and several matching layers or more advanced materials like charged cellular polypropylene. The relaxation time and the specific frequency of such mechanical ultrasound emitters limit the spectrum of applications for each device. A short pulse length is key for reliable defect detection and each component at test can be best characterized at material- and geometry-specific frequencies. Here we show that focused thermoacoustic transducers are suited for testing lightweight, structured composite plates. Since the ultrasound is generated in air, these transducers show no resonance behavior and emit a broadband acoustic spectrum between 1.2 kHz and 1 MHz. Composite specimens of 3 mm to 9 mm thickness made of polylactide with a honeycomb structure were tested. Flat bottom holes were introduced to quantify the spatial resolution of the imaging method inside the strongly anisotropic specimen. As no broadband receivers are available yet, cellular polypropylene transducers were used as receivers, which limits the bandwidth of the method towards the bandwidth of the receiver. Nevertheless, we demonstrate the competitiveness of the thermoacoustic transducer compared to mechanical emitters at their respective resonance frequencies. Because a thermoacoustic transmitter features a nearly ideal pulse width, a single transmitter can be coupled with receivers with different resonance frequencies. With the development of broadband ultrasound receivers, air-coupled ultrasound spectroscopy will likely be possible in the near future. The analysed transducer holds the potential to speed up testing during production and maintenance in aerospace and automotives. Its combination with a broadband receiver could also expand the application field of air-coupled ultrasonic testing from a qualitative error detection towards a quantitative, spatially resolved analysis of mechanical material properties. T2 - 10th International Symposium on NDT in Aerospace CY - Dresden, Germany DA - 24.10.2018 KW - Thermoacoustics KW - Ultrasonic Testing KW - Broadband KW - Ultrasound Emission PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464677 SN - 978-3-940283-96-2 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-46467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Z. A1 - Kruschwitz, Sabine A1 - Weller, A. A1 - Halisch, M. T1 - Enhanced pore space analysis by use of µ-CT, MIP, NMR, and SIP N2 - We investigate the pore space of rock samples with respect to different petrophysical parameters using various methods, which provide data on pore size distributions, including micro computed tomography (µ-CT), mercury Intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and spectral-induced polarization (SIP). The resulting cumulative distributions of pore volume as a function of pore size are compared. Considering that the methods differ with regard to their limits of resolution, a multiple-length-scale characterization of the pore space is proposed, that is based on a combination of the results from all of these methods. The approach is demonstrated using samples of Bentheimer and Röttbacher sandstone. Additionally, we compare the potential of SIP to provide a pore size distribution with other commonly used methods (MIP, NMR). The limits of Resolution of SIP depend on the usable frequency range (between 0.002 and 100 Hz). The methods with similar Resolution show a similar behavior of the cumulative pore volume distribution in the verlapping pore size range. We assume that µ-CT and NMR provide the pore body size while MIP and SIP characterize the pore throat size. Our study Shows that a good agreement between the pore radius distributions can only be achieved if the curves are adjusted considering the resolution and pore volume in the relevant range of pore radii. The MIP curve with the widest range in Resolution should be used as reference. KW - Pore space KW - Induced polarization KW - Mercury intrusion porosimetry KW - µ-CT KW - NMR PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465071 DO - https://doi.org/10.5194/se-9-1225-2018 SN - 1869-9510 SN - 1869-9529 VL - 9 IS - 6 SP - 1225 EP - 1238 PB - Copernicus Publications CY - Göttingen AN - OPUS4-46507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlichting, S. A1 - Hönig, Gerald A1 - Müßener, J. A1 - Hille, P. A1 - Grieb, T. A1 - Westerkamp, S. A1 - Teubert, J. A1 - Schörmann, J. A1 - Wagner, M.R. A1 - Rosenauer, A. A1 - Eickhoff, M. A1 - Hoffmann, A. A1 - Callsen, G. T1 - Suppression of the quantum-confined Stark effect in polar nitride heterostructures N2 - Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable. KW - Nanophotonics KW - Photonic devices KW - Single photon and quantum effects PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457884 DO - https://doi.org/10.1038/s42005-018-0044-1 SN - 2399-3650 VL - 1 SP - 1 EP - 8 PB - Springer Nature CY - London AN - OPUS4-45788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Camp, N. V. A1 - Kalinka, Gerhard A1 - Bergeler, J. T1 - Light-cured polymer electrodes for non-invasive EEG recordings N2 - We invented the first non-metallic, self-adhesive and dry biosignalling electrode. The PEDOT polymer electrode changes its aggregate state and conductivity by a light curing procedure. The electrode can be applied as a gel underneath hair without shaving. With the aid of blue light, the electrode can be hardened within a few seconds at the desired location on the scalp. The cured polymer electrode is highly conductive and can be applied on a very small location. Unlike other EEG electrodes, our electrode does not lose conductivity upon drying. Furthermore, our electrode strongly bonds to Skin and does not require any additional adhesive. Short circuits due to an outflow of gel are prevented with this technique. Therefore, the PEDOT polymer electrode is extremely well suited for applications that, up to now, have been challenging, such as non-invasive EEG recordings from awake and freely moving animals, EEG recordings from preterm babies in the neonatal intensive care unit or long-term recordings in the case of sleep monitoring or epilepsy diagnostics. We addressed two technical questions in this work. First, is the EEG recorded with polymer electrodes comparable to a standard EEG? Second, is it possible to record full-band EEGs with our electrodes? KW - Light curing KW - Polymer KW - Electric conductivity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459803 UR - https://rdcu.be/7aPD DO - https://doi.org/10.1038/s41598-018-32304-6 SN - 2045-2322 VL - 8 IS - 14041 SP - 1 EP - 9 PB - Nature Publishing Group CY - London AN - OPUS4-45980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhandarov, S. A1 - Mäder, E. A1 - Kalinka, Gerhard A1 - Scheffler, C. A1 - Poitzsch, C. A1 - Fliescher, S. T1 - Investigation of interfacial strength parameters in polymer matrix composites: Compatibility and reproducibility N2 - Effects of various geometrical and physical factors, as well as the method of data reduction (analysis of experimental forceedisplacement curves) on the values of local interfacial strength parameters (local IFSS, td, and critical energy release rate, Gic) determined by means of a single fiber pull-out test are discussed. Experimental results of our pull-out tests on several fiberepolymer matrix systems showed that td and Gic weakly depended on geometrical factors. However, the pull-out test appeared to be sensitive to the conditions of specimen formation and testing, such as changing the nature of the contacting surfaces (fiber sizing) and the fiber pull-out rate. Of several methods of td and Gic Determination from a forceedisplacement curve, the most reliable and reproducible one is the approach based on the values of the maximum force recorded in a pull-out test and the interfacial frictional force immediately after fiber debonding. KW - Interface KW - Interfacial shear strength KW - Pull-out composite materials KW - Polymer matrix composites KW - Critical energy release rate KW - Geometrical factors PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460918 DO - https://doi.org/10.1016/j.aiepr.2018.06.002 SN - 2542-5048 VL - 1 IS - 1 SP - 82 EP - 92 PB - Elsevier CY - Amsterdam AN - OPUS4-46091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Schadow, Florian A1 - Nielow, Dustin A1 - Trappe, Volker T1 - Air-coupled ultrasonic ferroelectret transducers with additional bias voltage for testing of composite structures N2 - Common air-coupled transducers for non-destructive testing consist of a piezocomposite material and several matching layers. Better acoustical matching to air is achieved by transducers based on charged cellular polypropylene (PP). This material has about hundred times lower acoustic impedance than any piezocomposite, having about the same piezoelectric coefficient. The piezoelectric properties of cellular PP are caused by the polarization of air cells. Alternatively, a ferroelectret receiver can be understood as a capacitive microphone with internal polarization creating permanent internal voltage. The sensitivity of the receiver can be increased by applying additional bias voltage. We present an ultrasonic receiver based on cellular PP including a high-voltage module providing bias voltage up to 2 kV. The application of bias voltage increased the signal by 12 to 15 dB with only 1 dB increase of the noise. This receiver was combined with a cellular PP transmitter in through transmission to inspect several test specimens consisting of glass-fiber-reinforced polymer face sheets and a porous closed-cell PVC core. These test specimens were inspected before and after load. Fatigue cracks in the porous PVC core and some fatigue damage in the face sheets were detected. These test specimens were originally developed to emulate a rotor blade segment of a wind power plant. Similar composite materials are used in lightweight aircrafts for the general aviation. The other inspected test specimen was a composite consisted of glass-fiber-reinforced polymer face sheets and a wooden core. The structure of the wooden core could be detected only with cellular PP transducers, while commercial air-coupled transducers lacked the necessary sensitivity. Measured on a 4-mm thick carbon-fiber-reinforced polymer plate, cellular PP transducers with additional bias voltage achieved a 32 dB higher signal-to-noise ratio than commercial air-coupled transducers. T2 - 10th International Symposium on NDT in Aerospace CY - Dresden, Germany DA - 26.10.2018 KW - Airborne ultrasonic testing KW - Air-coupled ultrasonic testing KW - Ferroelectret KW - Composites KW - Transducers PY - 2018 SP - 1 EP - 6 AN - OPUS4-46657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maiwald, Michael T1 - Voll integrierte und vernetzte Systeme und Prozesse - Perspektive: Smarte Sensorik, Aktorik und Kommunikation T1 - Fully integrated distributed systems and processes – Perspective: Smart sensors, actuators, and communication N2 - Unternehmen der chemischen Industrie müssen neuen Pfade beschreiten, um in einem veränderten Umfeld erfolgreich bestehen zu können. Dazu gehört insbesondere, das Potenzial digitaler Technologien zu nutzen. Die volle Integration und intelligente Vernetzung von Systemen und Prozessen kommt allerdings nur zögerlich voran. Dieser Beitrag ist ein Loblied auf die Feldebene. Er möchte dazu ermutigen, die Digitalisierung der Prozessindustrie auf Basis smarter Sensorik, Aktorik und Kommunikation ganzheitlicher zu denken und informiert über aktuelle technische Perspektiven, wie das Ein-Netzwerk-Paradigma, Ad-hoc-Vernetzungen, Edge-Computing, FPGAs, virtuelle Maschinen oder Blockchain. Diese geben smarter Sensorik, Aktorik und Kommunikation eine völlig neue Perspektive. N2 - Chemical companies must find new paths to success in a changing environment. In particular, this will involve exploiting the potential of digital technologies. However, the full integration and intelligent interconnection of systems and processes is only making slow progress. This contribution aims to encourage the more comprehensive use of digitization in the process industry based on smart sensors, actuators, and communications, and informs about current technical possibilities such as the “one-network paradigm”, ad-hoc connections, edge computing, FPGAs, virtual machines and blockchain. These offer a new scope for smart sensors, actuators, and communications. KW - Smarte Sensoren KW - Smarte Aktoren KW - Digitalisierung der Prozessindustrie KW - Prouess-Sensoren 4.0 KW - Smart sensors KW - Smart actuators KW - Digitization of process industry KW - Process sensors 4.0 PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-466642 DO - https://doi.org/10.17560/atp.v60i10.2376 SN - 2364-3137 VL - 60 IS - 10 SP - 70 EP - 85 PB - Vulkan Verlag CY - Essen AN - OPUS4-46664 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ivanov, Sergei A1 - Artinov, Antoni A1 - Valdaytseva, Ekaterina A1 - Stankevich, Stanislav A1 - Andreevich, Gleb T1 - A simplified model for numerical simulation of laser metal deposition process with beam oscillation N2 - A model of laser metal deposition with beam oscillation has been developed. The proposed model consists of two coupled sub-models calculating the heat transfer in the deposited part and the free surface of the molten pool, respectively. The heat transfer simulation of the deposited part solves a three-dimensional quasi-stationary heat conduction problem. The free surface of the molten pool are determined by solving the Laplace-Young equation. The developed model enables the layer-by-layer prediction of the shape of the deposited part and the resulting temperature field. It is shown that for an oscillation amplitude equal to the beam radius the peak value of the heat flux decreases by about 53% and 73% in the case of lateral oscillation and circular oscillation, respectively. Lateral oscillating laser beam results in a higher penetration depth due to the higher thermal efficiency. The amplitude of the laser beam oscillation effects the shape of the deposited wall and the deposition rate. A good correlation between the numerically calculated and experimentally observed results is obtained. KW - Laser metal deposition KW - Beam oscillation KW - Numerical modelling PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467081 DO - https://doi.org/10.1088/1742-6596/1109/1/012006 SN - 1742-6588 SN - 1742-6596 VL - 1109 SP - 012006, 1 EP - 8 PB - IOP Publ. CY - Bristol AN - OPUS4-46708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Tang, De-Hui A1 - Teng, Jun A1 - Said, Samir A1 - Rohrmann, Rolf T1 - Structural health monitoring of a prestressed concrete bridge based on statistical pattern recognition of continuous dynamic measurements over 14 years N2 - This work describes a vibration-based structural health monitoring of a prestressed-concrete box girder bridge on the A100 Highway in Berlin by applying statistical pattern recognition technique to a huge amount of data continuously collected by an integrated monitoring system during the period from 2000 to 2013. Firstly, the general condition and potential damage of the bridge is described. Then, the dynamic properties are extracted from 20 velocity sensors. Environmental variability captured by five thermal transducers and traffic intensity approximately estimated by strain measurements are also reported. Nonlinear influences of temperature on natural frequencies are observed. Subsequently, the measurements during the first year are used to build a baseline health index. The multiple linear regression (MLR) method is used to characterize the nonlinear relationship between natural frequencies and temperatures. The Euclidean distance of the residual errors is calculated to build a statistical health index. Finally, the indices extracted from the following years gradually deviate; which may indicate structural deterioration due to loss of prestress in the prestressed tendons. KW - Bridge KW - Structural health monitoring KW - Statistical pattern recognition KW - Temperature effect PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468126 DO - https://doi.org/10.3390/s18124117 SN - 1424-8220 VL - 18 IS - 12 SP - 4117, 1 EP - 28 PB - MDPI CY - 4052 Basel, Schweiz AN - OPUS4-46812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kauss, N. A1 - Rosemann, Paul A1 - Halle, T. T1 - Age-hardening behaviour, microstructure and corrosion resistance of the copper alloyed stainless steel 1.4542 N2 - The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion resistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromium carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation (EPR) was used to determine the corrosion resistance and detect chromium depletion in all heattreated states. The results show that a work hardening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion resistance due to chromium depletion. T2 - WTK2018 CY - Chemnitz DA - 14.03.2018 KW - Corrosion KW - Corrosion resistance KW - Corrosion testing KW - EPR KW - Heat treatment KW - Stainless steel PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452482 DO - https://doi.org/10.1088/1757-899X/373/1/012020 SN - 1757-899X SN - 1757-8981 VL - 373 SP - Article 012020, 1 EP - 9 PB - Institute of Physics CY - London AN - OPUS4-45248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lugovtsova, Yevgeniya A1 - Prager, Jens T1 - Analysis of Guided Wave Propagation in an Aluminium-CFRP Plate N2 - Guided waves cover comparably long distances and thus allow for online structural health monitoring of safety relevant components, e.g. lightweight composite overwrapped pressure vessels (COPV) as used for the transportation of pressurised gases. Reliable non-destructive assessment of COPVs’ condition is not available yet due to their complex composite structure comprising a thin metal liner and a fibre reinforced plastics (FRP) overwrap. The conventional overload hydrostatic pressure testing used for the metal vessels is not suitable for the composite vessels, because it may damage the FRP overwrap reducing the service life of the COPV. Therefore, ISO and CEN defined a maximum service life of composite pressure vessels as of 15 to 20 years. To extend the COPVs’ service life and to ensure a safer usage a structural health monitoring system based on guided ultrasonic waves is to be developed. In this contribution first results of guided waves propagation in a flat composite plate consisting of an aluminium layer firmly bonded to a carbon fibre reinforced plastic laminate are presented. Based on experimental results material properties of FRP are reconstructed by means of the Scaled Boundary Finite Element Method (SBFEM). T2 - ECNDT 2018 CY - Gothenburg, Sweden DA - 11.06.2018 KW - Structural Health Monitoring KW - Pressure tanks KW - Hydrogen storage KW - Natural gas KW - Composites PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452084 SP - 1 EP - 6 AN - OPUS4-45208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Kotschate, Daniel T1 - New technologies for air-coupled ultrasonic transducers N2 - Air-coupled ultrasonic testing (ACUT) has experienced rapid growth within the last years. It is especially well suited to inspection of lightweight structures consisting of composite materials and adhesive joints. Uniform coupling and easy maintenance are its advantages compared to contact technique. However, the impedance mismatch between the transducer and air poses a major challenge to the development of ACUT transducers. Commercially available air-coupled transducers consist of a piezocomposite material and matching layers. Their fabrication is difficult in handling and their signal-to-noise ratio sometimes not sufficient for various testing requirements. However, there are several innovative approaches using other materials and other physical principles to transmit and receive an ultrasonic pulse. We present a review of the latest advances in research on air-coupled transducers for non-destructive testing, including previously unpublished results. We recognize two major directions as most promising: ferroelectrets and thermoacoustic transducers. Ferroelectrets are charged cellular polymers exhibiting piezoelectric properties. Their small acoustic impedance is matched to air better than matching layers applied in conventional air-coupled transducers. Applying bias voltage to a ferroelectret receiver is the latest development in this field, which increased the received signal by 12 to 15 dB. Thermoacoustic transducers use heat to initiate an ultrasonic wave, acting as transmitters. The working principle is known from nature as thunder and lightning: thermal energy of an electrically heated material, which can also be air, is converted into acoustic energy. Some thermoacoustic transmitters consist of a conductive layer with a thickness in the nanometer range deposited on a solid substrate. Another possibility is to use an electric spark. For the first time, measurements of the sound field of an electric spark up to 500 kHz were performed. Thermoacoustic transducers enable excitation of extremely broadband pulses while producing high pressure levels, which opens new possibilities for advanced signal processing. T2 - 12th European conference on Non-Destructive Testing CY - Gothenburg, Sweden DA - 11.06.2018 KW - Air-coupled ultrasonic testing KW - Atmospheric pressure plasma KW - Cellular polypropylene KW - Ferroelectret KW - Transducer PY - 2018 SP - ECNDT-0608-2018, 1 EP - 9 AN - OPUS4-45209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grager, J.-C. A1 - Kotschate, Daniel A1 - Gamper, J. A1 - Gaal, Mate A1 - Pinkert, K. A1 - Mooshofer, H. A1 - Goldammer, M. A1 - Grosse, C. U. T1 - Advances in air-coupled ultrasonic testing combining an optical microphone with novel transmitter concepts N2 - Air-coupled ultrasound (ACU) is increasingly used for automated and contactless inspection of large-scale composite structures as well as for non-destructive testing (NDT) of water-sensitive or porous materials. The major challenge to overcome using ACU in NDT is the enormous loss of ultrasonic energy at each solid-air interface caused by the high acoustic impedance mismatch. Resonant low-frequency piezoceramic transducers are specially designed to achieve high sound pressure levels. For an expanded use of this technique, however, the spatial resolution needs to be increased. Recent studies of our collaborative research group demonstrated the successful application of a resonance-free, highly sensitive receiver that uses a Fabry-Pérot etalon instead of piezoceramic materials or membranes. However, to reach the full potential of this broadband small-aperture optical microphone, novel transmitter concepts have to be developed and evaluated for advanced NDT applications. Different types of transmitter were tested in combination with the optical microphone acting as receiver and they were compared to conventional piezoceramic transducers in through-transmission mode. Monolithic carbon fiber-reinforced plastics (CFRP) and CFRP sandwich structures containing different defect types were inspected. Presented results are processed as C-scan images and further evaluated for spatial resolution, signal-to-noise ratio and sensitivity of each measurement setup. Novel transmitter concepts, such as ferroelectret and thermoacoustic emitters, show promising findings with a considerably improved time and spatial resolution for ACU-NDT. T2 - 12th European conference on Non-Destructive Testing CY - Gothenburg, Sweden DA - 11.06.2018 KW - Air-coupled ultrasonic testing KW - Optical microphone KW - Thermoacoustic KW - Cellular polypropylene KW - Ferroelectret KW - Transducer PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452114 SP - ECNDT-0166-2018, 1 EP - 10 AN - OPUS4-45211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yalçin, M. A1 - Taşçioğlu, C. A1 - Plarre, Rüdiger A1 - Akçay, Ç. A1 - Busweiler, Sabine T1 - Investigation of natural durability of some native and exotic wood species against Hylotrupes bajulus (Cerambycidae) and Anobium punctatum (Anobiidae) N2 - Aim of study: In this study, natural durability of some domestic and foreign wood species against Hylotrupes bajulus and Anobium punctatum larvae were tested on laboratory scale Area of study: This study was conducted at Department of Forest Products Engineering in Duzce University, Turkey and Federal Institute for Materials Research and Testing (BAM), Germany. Material and Methods: Scotch pine (Pinus sylvestris), fir (Abies nordmanniana), spruce (Picea orientalis), cedar (Cedrus libani), poplar (Populus tremula) and beech (Fagus orientalis) woods were used to test H. bajulus larvae (EN 46-1). Alder (Alnus glutinosa), oak (Quercus cerris), poplar (Populus tremula), beech (Fagus orientalis), maple (Acer carpinifolium), ash (Fraxinus angustifolia), teak (Tectona grandis), ayous (Triplochiton scleroxylon), movingui (Distemonanthus benthamianus), dahoma (Piptadeniastrum africanum), iroko (Chlorophora excelsa), bubinga (Guibourtia tessmannii) and sapele (Entandrophragma cylindiricum) woods were used for A. punctatum larvae (EN 49-1). At the end of the experiment, the mortality rates of the larvae were determined and the size and weights of the surviving larvae were measured. Main results: F. orientalis and C. libani were found to be the most resistant wood species against H. bajulus larvae while A. nordmanniana was the least resistant. All tropical wood species and oak and maple from domestic wood species showed 100% mortality rate therefore found to be the most resistant against A. punctatum larvae. The most vulnerable wood species was found to be alder with a 35% mortality. Research highlights: while F. orientalis, C. libani, and P. tremula were found the most resistance wood species against H. bajulus, P. sylvestris and A. nordmanniana were determined as most vulnerable. All tropical wood species and two domestic species (Q. cerris and A. carpinifolium) showed the highest mortality rate as 100%. The least durable domestic wood was determined as alder. KW - Hylotrupes bajulus, Anobium punctatum, natural durability, tropical wood, native wood. PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446572 DO - https://doi.org/10.17475/kastorman.311971 SN - 1303-2399 SN - 1309-4181 VL - 18 IS - 1 SP - 83 EP - 91 PB - Kastamonu University CY - Kastamonu AN - OPUS4-44657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Franz, Philipp A1 - Metz, Christain A1 - Brackrock, Daniel A1 - Fischer, C. A1 - Wachtendorf, Volker A1 - Maierhofer, Christiane T1 - Zerstörungsfreie Charakterisierung und Qualitätssicherung der Materialeigenschaften und Beständigkeit additiv gefertigter Kunststoffteile N2 - Mit additiven Fertigungsverfahren hergestellte Bauteile und Produkte aus Kunststoffen werden zunehmend nicht mehr nur als Prototypen, sondern als voll funktionsfähige Bauteile und Produkte gefertigt. Bedingt durch die Fertigungsprozesse und den schichtweisen Aufbau resultieren physikalische Materialeigenschaften, die stark von den Fertigungsparametern abhängen und zudem anisotrop sind. Von den Fertigungsparametern werden auch die Oberflächeneigenschaften beeinflusst, sodass zu erwarten ist, dass sich die Beständigkeit gegenüber äußeren Umwelteinflüssen bei additiv gefertigten Bauteilen von der konventionell gefertigter unterscheiden kann. Nachfolgend wird daher die Entwicklung eines Qualitätssicherungskonzeptes basierend auf spektroskopischen und zerstörungsfreien Prüfverfahren vorgestellt, in dem der Alterungsprozess von mittels Fused Deposition Modelling (FDM) und mittels Lasersintering (LS) hergestellten Probekörpern untersucht wird. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Additive Fertigung KW - Kunststoffe KW - Zerstörungsfreie Prüfung PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449016 SN - 978-3-940283-92-4 VL - DGZfP BB 166 SP - Mo.2.A.1, 1 EP - 9 AN - OPUS4-44901 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Pentzien, Simone A1 - Dittmar, G. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission as a potential hazard during ultrashort pulse laser material processing N2 - In laser machining with ultrashort laser pulses unwanted X-ray radiation in the keV range can be generated when a critical laser intensity is exceeded. Even if the emitted X-ray dose per pulse is low, high laser repetition rates can lead to an accumulation of X-ray doses beyond exposure safety limits. For 925 fs pulse duration at a center wavelength of 1030 nm, the X-ray emission was investigated up to an intensity of 2.6 × 10^14 W/cm2. The experiments were performed in air with a thin disk laser at a repetition rate of 400 kHz. X-ray spectra and doses were measured for various planar target materials covering a wide range of the periodic table from aluminum to tungsten. Without radiation shielding, the measured radiation doses at this high repetition rate clearly exceed the regulatory limits. Estimations for an adequate radiation shielding are provided. KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Femtosecond laser KW - Radiation protection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448431 DO - https://doi.org/10.1007/s00339-018-1828-6 SN - 0947-8396 SN - 1432-0630 VL - 124 IS - 6 SP - Article 407, 1 EP - 8 PB - Springer AN - OPUS4-44843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Heckel, Thomas A1 - Brackrock, Daniel A1 - Gaal, Mate T1 - Charakterisierung von Impactschäden während und nach der Belastung mit thermografischen Verfahren und mit Ultraschall N2 - Der Umfang der durch Impacts in Faserverbundmaterialien erzeugten Schäden ist abhängig von der Energie des Impacts, von der Zusammensetzung und dem Aufbau der Faserverbundwerkstoffe und von der Geometrie der Bauteile und hier im Wesentlichen von der Dicke des Bauteils. Der zerstörungsfreie Nachweis dieser Schädigungen kann sowohl mit Ultraschallverfahren als auch mit Verfahren der aktiven Thermografie erfolgen. Ein Vergleich der Nachweisempfindlichkeiten dieser Verfahren für die unterschiedlichen Schädigungen wird in diesem Beitrag in Abhängigkeit vom verwendeten Faserverbundwerkstoff (CFK und GFK), der Dicke des Materials und von der Impactenergie durchgeführt. Ergänzt werden die im Anschluss an die Schädigung eingesetzten ZfP-Verfahren mit zeitlich hochaufgelösten Thermografiemessungen, die bereits während des Impacts aufgenommen wurden. T2 - DGZfP Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Thermografie KW - Ultraschall KW - Faserverbundwerkstoffe KW - Impactschäden PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448773 SN - 978-3-940283-92-4 VL - 166 SP - 1 EP - 8 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-44877 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illerhaus, Bernhard A1 - Kunisch, E. A1 - Kinne, R. W. T1 - μCT begleitete in-situ Druckversuche an spongiösem Knochen - Vergleich(ende Bestimmung) des experimentellen und simulierten Verschiebungsfeldes mit der simulierten internen Spannung N2 - Untersuchungen haben gezeigt, dass sich ältere Schafe gut als Modell für die mi-nimalinvasive Behandlung von Osteoporose eignen [1]. Um einen Behandlungs-effekt nachzuweisen, wird dabei unter anderem die Belastungsfähigkeit des Kno-chens durch Druckversuche an kleinen Zylindern aus den behandelten und unbe-handelten Knochen bestimmt. Diese hatten hier einen Durchmesser von 10 mm und eine Höhe von 13 mm. Für den in-situ Druckversuch wurde eine Deben CT5000 verwendet. In einer Serie von Druckerhöhungen wurden die Proben je-weils tomographiert. Dabei ergab sich zunächst, dass mit der µCT innerhalb der Knochen im oberen und unteren Bereich schon Brüche nachgewiesen werden können, obwohl die gemessene Kraftaufnahmekurve keine Unstetigkeit zeigt. Deswegen wurden die starren Probenaufnehmer der Deben Anordnung durch bewegliche Aufnehmer ergänzt, die eine leichte Verkippung der belasteten Ober-flächen ausgleichen können. Ein Vergleich der gemessenen und der aus den µCT-Daten berechneten Verschiebungsfelder ergab trotz der komplexen Struktur der Knochen gute Übereinstimmungen. Diese Verschiebungen wurden dann mit den aus den µCT Daten simulierten mechanischen Druckversuchen, Von-Mise-Spannungen und daraus berechneten Verschiebungen verglichen. (VGStudioMax Simulation). T2 - DGZfP-Jahrestagung CY - Leipzig, Germany DA - 07.05.2018 KW - Computer Tomographie KW - In-situ Druckversuch KW - Simulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448827 UR - https://www.ndt.net/?id=23080 SN - 978-3-940283-92-4 VL - DGZfP BB 166 SP - 1 EP - 7 PB - DGZfP CY - Berlin AN - OPUS4-44882 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapa, Thomas A1 - Schreier, Andy A1 - Krebber, Katerina T1 - 63 km BOFDA for temperature and strain monitoring N2 - We demonstrate (and are the first to do so) 63 km Brillouin Optical Frequency-Domain Analysis (BOFDA) for temperature and strain monitoring using a 100 km fiber loop. The use of BOFDA for long-range applications can be considered a novel approach, as previous investigations focused on the utilization of Brillouin Optical Time-Domain Reflectometry and Analysis (BOTDR and BOTDA, respectively). At 51.7 km, a 100 m hotspot (37 °C) was detected without using distributed Raman amplification or image processing. KW - Distributed sensing KW - Stimulated Brillouin scattering KW - Fiber optics sensors PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449679 DO - https://doi.org/10.3390/s18051600 SN - 1424-8220 VL - 18 IS - 5 SP - 1600, 1 EP - 9 PB - MDPI CY - Basel, Switzerland AN - OPUS4-44967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Franz-Georg A1 - Holm, Olaf T1 - Resources from recycling and urban mining: Limits and prospects N2 - Direct and indirect effects (DIERec) of the recovery of secondary resources are in the range of 500 million tons per year in Germany; energy savings are 1.4 million TJ. These savings are between 10 and 20% of the total. The effects of materials recovery exceed those of energy recovery by far except for secondary plastic material, where DIERec from energy recovery is higher by factor of 2.7. Untapped potential for the recovery of secondary resources exists in the fine fraction of bottom ash from municipal solid waste incineration, mainly Cu and precious metals, and in urban mining. KW - Waste treatment KW - Secondary raw materials KW - Direct material input KW - Urban mining PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453364 UR - https://digital.detritusjournal.com/articles/resources-from-recycling-and-urban-mining-limits-and-prospects/124 DO - https://doi.org/10.31025/2611-4135/2018.13665 SN - 2611-4135 VL - 02 SP - 24 EP - 28 PB - CISA Publisher CY - Padua, Italy AN - OPUS4-45336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Metz, Christian A1 - Franz, Philipp A1 - Fischer, C. A1 - Wachtendorf, Volker A1 - Maierhofer, Christiane T1 - Active thermography for quality assurance of 3D-printed polymer structures N2 - Additively manufactured test specimens made of polyamide 12 (PA 12) by Laser Sintering (LS) as well as of acrylnitril-butadien-styrol (ABS) by Fused Layer Modeling (FLM), were tested with active thermography. For this, two different excitation methods (flash and impulse excitation) were used and compared, regarding the suitability for the detection of constructed and imprinted defects. To increase the quality of the thermograms, data processing methods like thermal signal reconstruction (TSR) and Fourier-Transformation were applied. Furthermore, the long-term stability of the probes towards environmental stress, like UV-radiation, heat, water contact and frost is being investigated in the presented project with artificial weathering tests. T2 - 14th Quantitative InfraRed Thermography Conference CY - Berlin, Germany DA - 25.06.2018 KW - Additive manufacturing KW - Active thermography KW - Artificial weathering PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453919 SP - Tu.3.A.2, 1 EP - 9 AN - OPUS4-45391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illerhaus, Bernhard A1 - Kunisch, E. A1 - Kinne, R. W. T1 - Serial in situ compression of spongiosa cylinder observed by μCT, compared to simulated stress, strain, and movement N2 - Minimally invasive injection of calcium phosphate cement into bone defects in aged sheep vertebrae has been used as a model for the treatment of osteoporotic vertebral fractures. One of the therapeutic criteria is a compression test of non-treated or treated vertebral bodies. In the present study, an in situ compression test with a stepwise load increase was performed with small spongiosa cylinders from the vertebrae under continuous monitoring by μCT. This allows localization of bone cracks and the visualization of correct placement and form of the bone cylinder. In addition, the effects of an uneven load distribution on the sample due to an irregular shape and a subsequent underperformance of the test sample can be excluded by controlling its shape under increasing load. There was a good agreement between the measured data and those obtained by simulated load-dependent transformation on the basis of a digital volume correlation between consecutive compression tests on the bone surface under the assumption of homogeneous bone material. Mechanic simulation was executed by directly using structural voxel data, resulting in maps of Von Mise stresses and predicted displacements. T2 - 12th ECNDT CY - Gothenburg, Sweden DA - 11.6.2018 KW - Computed tomography KW - In-situ compression KW - Simulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453317 SN - 978-91-639-6217-2 SP - 0162, 1 EP - 7 AN - OPUS4-45331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Schadow, Florian A1 - Nielow, Dustin A1 - Trappe, Volker T1 - Prüfung von Rotorblattschalen mit Luftultraschall N2 - Um den sicheren Betrieb von Windkraftanlagen zu gewährleisten, werden Rotorblätter nach der Fertigung und nach Reparatur mit verschiedenen zerstörungsfreien Verfahren auf Schaden untersucht. Bei der Fertigung von Blattschalen, die in einer Sandwich-Schalenbauweise gefertigt werden, entstehen Imperfektionen, die unter Belastung zu großen Rissen führen können. Zur Prüfung von Blattschalen wird unter anderem Ultraschallprüfung in Kontakttechnik eingesetzt. Um den Wartungsaufwand von Ultraschallanlagen zu reduzieren und um manche Kompositstrukturen vor Koppelmittel zu schützen, wird die Anwendung von Luftultraschall erforscht. Insbesondere große Fortschritte gibt es im Bereich der Entwicklung neuer Wandler. In diesem Beitrag berichten wir über die Luftultraschallprüfung von Schalen für Rotorblätter. Es wurden typische Sandwichschalenstrukturen hergestellt und mit einem eigenentwickelten Schalenprüfstand unter simulierter Betriebsbeanspruchung belastet. Die in den Schalenprüfkörpern entstandenen Schäden wurden außerhalb des Prüfstandes mit Luftultraschall in Durchschallung untersucht. Es wurden fokussierende Wandler auf Basis von Ferroelektreten entwickelt und für diese Prüfungen eingesetzt. Mit zusätzlicher elektrischer Vorspannung konnte die Empfindlichkeit der Empfänger deutlich erhöht werden. Die nach dem Lastwechsel entstandenen Schäden in den Rotorblattschalen waren eindeutig zu detektieren. T2 - DGZfP-Jahrestagung CY - Leipzig, Germany DA - 07.05.2018 KW - Wandler KW - Rotorblattschalen KW - Luftultraschall KW - Ferroelektret PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453066 SP - 7 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-45306 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Maierhofer, Christiane A1 - Heckel, Thomas A1 - Brackrock, Daniel A1 - Gower, M. A1 - Lodeiro, M. A1 - Baker, G. T1 - Quantitative comparison of different non-destructive techniques for the detection of artificial defects in GFRP N2 - In order to test their suitability different non-destructive methods were performed to inspect a GFRP plate with artificial defects. These defects were manufactured by means of thin PTFE sheets inserted between two plies in three different depth. The inspection methods were microwave reflection, flash thermography and phased array ultrasonics, all applied to the same specimen. Selected results are shown for all methods demonstrating opportunities and limits of the particular inspection methods. The achieved detection limits and further application aspects are compared directly to provide a useful information for the planning of inspection tasks. T2 - ECNDT CY - Gothenburg, Sweden DA - 11.06.2018 KW - Fiber resisted polymers KW - Non-destructive testing KW - Thermographic testing KW - Ultrasonic testing PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453728 SP - ECNDT-0247-2018 AN - OPUS4-45372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Ziegler, Mathias A1 - Maierhofer, Christiane ED - Maldague, X. T1 - Systematic errors in the evaluation of uncorrected data from thermographic lock-in measurements N2 - Lock-in thermography (LT) is based on the correct evaluation of phase differences between the temperature oscillations at different surface regions of the object under test during periodic heating. Since the usual heating procedures contain a DC component, the actual heating pattern achieved is not harmonic. This causes systematic deviations when phase differences are determined by means of harmonic analysis, e.g. with FFT analysis. The resulting errors depend clearly on the ratio between DC and AC amplitude, which is demonstrated at simulated and experimentally recorded temperature transients. Further experimental LT data obtained by different oscillating energy inputs showed a variety of possible shapes of transients with different DC components. T2 - 14th QIRT Conference CY - Berlin, Germany DA - 26.06.2018 KW - NDT KW - Lock-in Thermography KW - FFT PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453768 SP - 539 EP - 547 PB - QIRT Council AN - OPUS4-45376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Anja A1 - Swaraj, S. A1 - Sparnacci, K. A1 - Unger, Wolfgang T1 - Shell thickness determination for PTFE‐PS core‐shell nanoparticles using scanning transmission X‐ray microscopy (STXM) N2 - A scanning transmission X‐ray microscopy (STXM)‐based methodology is introduced for determining the dimensions (shell thickness, core and total diameter) of core‐shell nanoparticles, which exhibit a strong X‐ray absorption contrast and a well‐defined interface between core and shell material. A low radiation dosage during data acquisition and, therefore, less X‐ray beam‐induced damage of the sample is achieved by recording STXM images only at 2 predetermined energies of maximum Absorption contrast, instead of recording a stack of images across the whole absorption edge. A model core‐shell nanoparticle, polytetrafluoroethylene (PTFE) cores with polystyrene (PS) shell, is used for demonstration. Near‐edge X‐ray absorption fine structure spectroscopy confirms the significant difference in X‐ray absorption behavior between PTFE and PS. Additionally, because of the insolubility of styrene in PTFE a well‐defined interface between particle core and shell is expected. To validate the STXM results, both the naked PTFE cores as well as the complete core‐shell nanoparticles are examined by scanning electron microscopy (SEM). The introduced STXM‐based methodology yields particle dimensions in agreement with the SEM results and provides additional information such as the position of the particle core, which cannot be extracted from a SEM micrograph. T2 - European conference on applications of surface and interface analysis (ECASIA'17) CY - Montpellier, France DA - 24.09.2017 KW - Core-shell nanoparticles KW - Polymers KW - PS KW - PTFE KW - SEM KW - STXM PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449700 DO - https://doi.org/10.1002/sia.6464 SN - 1096-9918 SN - 0142-2421 VL - 50 IS - 11 SP - 1077 EP - 1082 PB - John Wiley & Sons CY - Hoboken, New Jersey, USA AN - OPUS4-44970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lugovtsova, Yevgeniya A1 - Bulling, Jannis A1 - Krome, Fabian A1 - Prager, Jens T1 - Effiziente Modellierung von geführten Wellen mit der Scaled Boundary Finite Elemente Methode und deren Anwendung für Composite-Druckbehälter N2 - Die Scaled Boundary Finite Elemente Methode (SBFEM) ist eine semi-analytische Methode, die speziell für Modellierung von geführten Wellen weiterentwickelt und optimiert wurde. Da nur den Rand der Rechendomäne diskretisiert wird, hat die SBFEM einen geringen Rechenaufwand. In diesem Beitrag wird die SBFEM benutzt, um die Ausbreitung geführter Wellen in einer Metall-Faserverbund-Werkstoffstruktur zu analysieren. Mittels der SBFEM ist es möglich, verschiede Fehlertypen, z.B. Ermüdungsrisse, Poren, Delaminationen, Korrosion, in das numerische Modell zu integrieren und damit Defekt-Mode-Wechselwirkung zu analysieren. Die Ergebnisse wurden für die Entwicklung einer Methode zur Zustandsüberwachung von Composite-Druckbehältern verwendet. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Wasserstoffspeicher KW - Automobilindustrie KW - Kohlenstofffaserverstärkter Kunststoff KW - Hybrid Materialien PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449797 SP - 1 EP - 4 AN - OPUS4-44979 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilrich, Cordula A1 - Brandes, E. A1 - Michael-Schulz, Heike A1 - Schröder, Volkmar A1 - Schwarz, Silke T1 - Classification of chemicals according to UN-GHS and EU-CLP: A review of physical hazard classes and their intricate interfaces to transport and former EU legislation N2 - The Globally Harmonized System of Classification and Labelling of Chemicals (UN-GHS) is being implemented in more and more countries all over the world; the EU has done so with the CLP-Regulation (EU-CLP). Compared to the undeniably important questions on health and environmental hazards, the classification of physical hazards of chemicals often has not been in the focus, although their implementation can be challenging and there are traps and pitfalls to be avoided. The following overview of the classification systematics for physical hazards aims at a principle understanding without detailing all criteria or test methods. Similarities and differences between the classification systems of the UN-GHS and EU-CLP, the transport of dangerous goods and the former EU system are reviewed with regard to the physical hazard classes. Available physical hazard classifications for the transport of dangerous goods and according to the former EU system can be used as available information when classifying according to the GHS. However, the interfaces of these classification systems and their limitations have to be understood well when concluding on GHS/CLP classifications. This applies not only to industry when applying CLP but especially to legislators when adapting legislation that in one way or another refers to the classification of chemicals. KW - Chemicals classification KW - Globally harmonized system of classification and labelling of chemicals KW - Hazardous chemicals KW - Physical hazards KW - UN-GHS KW - EU-CLP KW - CLP-regulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-450012 UR - https://osjournal.org/ojs/index.php/OSJ/article/view/1389 DO - https://doi.org/10.23954/osj.v3i2.1389 SN - 2466-4308 VL - 3 IS - 2 SP - 1 EP - 24 PB - NVO Start CY - Temerin AN - OPUS4-45001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dmitriev, A. I. A1 - Nikonov, A. Y. A1 - Österle, Werner T1 - Molecular dynamics modeling of the sliding performance of an amorphous silica nano-layer - The impact of chosen interatomic potentials N2 - The sliding behavior of an amorphous silica sample between two rigid surfaces is in the focus of the present paper. Molecular Dynamics using a classical Tersoff’s potential and a recently developed ReaxFF potential was applied for simulating sliding within a thin film corresponding to a tribofilm formed from silica nanoparticles. The simulations were performed at different temperatures corresponding to moderate and severe tribological stressing conditions. Simulations with both potentials revealed the need of considering different temperatures in order to obtain a sound interpretation of experimental findings. The results show the striking differences between the two potentials not only in terms of magnitude of the resistance stress (about one order of magnitude) but also in terms of friction mechanisms. The expected smooth sliding regime under high temperature conditions was predicted by both simulations, although with Tersoff’s potential smooth sliding was obtained only at the highest temperature. On the other hand, at room temperature Tersoff-style calculations demonstrate stick-slip behavior, which corresponds qualitatively with our experimental findings. Nevertheless, comparison with a macroscopic coefficient of friction is not possible because simulated resistance stresses do not depend on the applied normal pressure. KW - Molecular dynamics KW - Thin tribofilm KW - Resistance stress KW - Sliding simulation KW - Amorphous silica PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449366 DO - https://doi.org/10.3390/lubricants6020043 SN - 2075-4442 VL - 6 IS - 2 SP - 43, 1 EP - 11 PB - MDPI CY - Basel AN - OPUS4-44936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaiser, T. M. A1 - Braune, C. A1 - Kalinka, Gerhard A1 - Schulz-Kornas, E. T1 - Nano-indentation of native phytoliths and dental tissues: implications for herbivore-plant combat and dental wear proxies N2 - Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives. KW - Phytolith KW - Indentation hardness KW - Enamel KW - Dentine KW - Tooth wear PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-451417 UR - http://zoobank.org/5C7DBB2B-B27D-4CE6-9656-33C4A0DA0F39 DO - https://doi.org/10.3897/evolsyst.2.22678 VL - 2 SP - 55 EP - 63 PB - PENSOFT CY - USA AN - OPUS4-45141 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Wavelength-scanning coherent OTDR for dynamic high strain resolution sensing N2 - Distributed vibration sensing in optical fibers opened entirely new opportunities and penetrated various sectors from security to seismic monitoring. Here, we demonstrate a most simple and robust approach for dynamic strain measurement using wavelength-scanning coherent optical time domain reflectometry (C-OTDR). Our method is based on laser current modulation and Rayleigh backscatter shift correlation. As opposed to common single-wavelength phase demodulation techniques, also the algebraic sign of the strain change is retrieved. This is crucial for the intended applications in structural health monitoring and modal analysis. A linear strain response down to 47.5 pε and strain noise of 100 pε/√Hz is demonstrated for repetition rates in the kHz range. A field application of a vibrating bridge is presented. Our approach provides a cost-effective high-resolution method for structural vibration analysis and geophysical applications. KW - Fiber optics sensors KW - Optical time domain reflectometry KW - Rayleigh Scattering KW - Distributed acoustic sensing KW - Distributed strain sensing PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448069 DO - https://doi.org/10.1364/OE.26.010573 SN - 1094-4087 VL - 26 IS - 8 SP - 10573 EP - 10588 PB - Optical Society of America AN - OPUS4-44806 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Köpp, Christian A1 - Timofeev, Juri A1 - Azari, H. T1 - Controlled creating of cracks in concrete for non-destructive testing N2 - The non-destructive assessment of cracks in concrete is a common task for which non-destructive evaluation solutions have been published. Primarily, these tests have been carried out on artificial cracks that have been created by using notches instead of natural cracks. This study evaluates a procedure designed to create reproducible and controlled cracks in concrete. The procedure is based on using expanding mortar in a series of blind holes. This is done in combination with carefully aligned reinforcement to guide the direction of the crack development. The depth of the crack is also controlled by reinforcement. Crack depth varies statistically in the range of the Maximum aggregate size (16 mm) used for concrete. KW - Non-destructive testing of concrete KW - Cracks KW - Reference specimen PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457367 UR - https://rdcu.be/4IPN DO - https://doi.org/10.1007/s10921-018-0517-x SN - 0195-9298 SN - 1573-4862 VL - 37 IS - 3 SP - 67, 1 EP - 9 PB - Springer CY - New York AN - OPUS4-45736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Talebi, Elnaz A1 - Korzen, Manfred A1 - Espinós, A. A1 - Hothan, Sascha ED - Albero, Vicente T1 - The effect of damage location on the performance of seismically damaged concrete filled steel tube columns at fire N2 - In this paper, a nonlinear three-dimensional finite element (FE) model was developed and validated to study the effect of seismic damage location on the response of concrete filled tube (CFT) columns at fire after earthquakes. Three analyses were conducted consecutively in the modelling, namely, cyclic, thermal and structural. Results of the cyclic loading analysis comprising residual deformations were applied as the Initial condition to the thermal-stress model, replicating the seismic performance of column. Following, a nonlinear sequentially coupled-thermal stress Analysis was carried out to investigate the fire response of CFT columns after the seismic event. Three damage scenarios were contemplated, considering any possible potential damages that could be generated by the earthquake loading on CFT columns. The accuracy of the proposed FE model was examined by comparing the numerical results with that of available tests on fire and cyclic loading. By means of the validated model, the performance of damaged CFT columns was then investigated under fire after earthquakes. The level of damage was assumed as a high damage level, presuming that the column reached 50% of ist lateral resistance while still maintaining its overall stability after the earthquake. The results were presented broadly, including the axial deformation history as well as the fire resistance time for CFT columns. To have a comprehensive insight on the influence of damage location in columns, the fire response of damaged specimens was compared with that of an intact one. T2 - 12th International Conference on Advances in Steel-Concrete Composite Structures (ASCCS 2018) CY - Valencia, Spain DA - 27.06. 2018 KW - Fire after earthquake KW - Concrete filled tube (CFT) column KW - Finite element model KW - Seismically damaged column KW - Damage location KW - Fire performance PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457694 SN - 978-84-9048-601-6 DO - https://doi.org/10.4995/ASCCS2018.2018.8534 SP - 835 EP - 842 PB - Editorial Universitat Politècnica de València CY - València AN - OPUS4-45769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ziegler, Mathias A1 - Thiel, Erik A1 - Ahmadi, Samim T1 - Lock-in Thermography using High-Power Laser Sources N2 - Optical lock-in thermography is a completely contactless and very sensitive NDT technique. As an optical source of energy, incandescent lamps are most commonly used because they are relatively inexpensive and offer high irradiances at the test specimen. However, they are strongly restricted by their low modulation bandwidth with a maximum modulation frequency of only about 1 Hz. The use of high-power kilowattclass laser sources, e.g. diode laser arrays, pushes this constraint beyond 100 Hz. This allows for the exploration of the near-surface region of metals and layer systems with better and more accurate penetration depth and depth resolution. Moreover, these lasers are virtually free of any additional thermal radiation that could interfere with the “true” thermal response emitted from the heated sample. In turn, they can be easily used in a one-sided test configuration. We present current activities with kilowatt-class highpower laser sources for advanced lock-in thermography and focus on the application of laser arrays that offer a very high irradiation strength over a large sample area beyond the mentioned advantages. T2 - 12th European Conference on Non-destructive Testing CY - Gothenburg, Sweden DA - 11.06.2018 KW - Thermography KW - Laser Thermography KW - Lock-in Thermography PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454466 UR - http://cdn.ecndt2018.com/wp-content/uploads/2018/05/ecndt-0139-2018.pdf SN - 978-91-639-6217-2 SP - ECNDT-0139-2018,1 EP - 7 AN - OPUS4-45446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burgholzer, P. A1 - Berer, T. A1 - Ziegler, Mathias A1 - Thiel, Erik A1 - Ahmadi, Samim A1 - Gruber, J. A1 - Mayr, G. A1 - Hendorfer, G. T1 - Blind structured illumination as excitation for super-resolution photothermal radiometry N2 - Using an infrared camera for radiometric imaging allows the contactless temperature measurement of multiple surface pixels simultaneously. From the measured surface data, a sub-surface structure, embedded inside a sample or tissue, can be reconstructed and imaged when heated by an excitation light pulse. The main drawback in radiometric imaging is the degradation of the spatial resolution with increasing depth, which results in blurred images for deeper lying structures. We circumvent this degradation with blind structured illumination, combined with a non-linear joint sparsity reconstruction algorithm. The ground-breaking concept of super-resolution can be transferred from optics to thermographic imaging. T2 - Conference QIRT 2018 CY - Berlin, Germany DA - 25.06.2018 KW - Thermography KW - Laser thermography KW - Super resolution PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454506 SN - 978-3-940283-94-8 DO - https://doi.org/10.1080/17686733.2019.1655247 SP - We.3.A.2, 1 EP - 7 AN - OPUS4-45450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lugovtsova, Yevgeniya A1 - Bulling, Jannis A1 - Prager, Jens A1 - Boller, C. T1 - Efficient modelling of guided ultrasonic waves using the Scaled Boundary FEM towards SHM of composite pressure vessels N2 - The Scaled Boundary Finite Element Method (SBFEM) is a semi-analytical method that shows promising results in modelling of guided ultrasonic waves. Efficiency and low computational cost of the method are achieved by a discretisation of the boundary of a computational domain only, whereas for the domain itself the analytical solution is used. By means of the SBFEM different types of defects, e.g. cracks, pores, delamination, corrosion, integrated into a structure consisting of anisotropic and isotropic materials can be modelled. In this contribution, the SBFEM is used to analyse the propagation of guided waves in a structure consisting of an isotropic metal bonded to anisotropic carbon fibre reinforced material. The method allows appropriate wave types (modes) to be identified and to analyse their interaction with different defects. Results obtained are used to develop a structural health monitoring system for composite pressure vessels used in automotive and aerospace industries. T2 - 9th European Workshop on Structural Health Monitoring (EWSHM) CY - Manchester, UK DA - 10.07.2018 KW - Structural Health Monitoring KW - Pressure tanks KW - Hydrogen storage KW - Finite Element Modelling KW - Composites PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454859 SP - 1 EP - 7 AN - OPUS4-45485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Heckel, Thomas A1 - Brackrock, Daniel A1 - Gaal, Mate T1 - Quantification of impact damages in CFRP and GFRP structures with thermography and ultrasonics N2 - The extent of damage caused by impacts in fibre reinforced composites depends on the energy of the impacts, on the velocity and the shape of the impacting body, on the material and structure of the composite and on the geometry of the structure. Here, mainly the thickness of the component is essential. The non-destructive evaluation of these damages can be carried out using both ultrasound and active thermography methods. A comparison of the detection sensitivity of these methods for the different damages is carried out in this paper depending on the fibre composite material used (CFRP and GFRP), the thickness of the material and the impact energy. The NDT methods used after the damage are supplemented by thermographic measurements with high temporal resolution, which were already recorded during the impact. T2 - 14th Quantitative InfraRed Thermography Conference CY - Berlin, Germany DA - 25.06.2018 KW - Active thermography KW - Passive thermography KW - Ultrasonics KW - CFRP KW - GFRP KW - Impact PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454952 UR - http://www.qirt.org/archives/qirt2018/papers/126.pdf DO - https://doi.org/10.21611/qirt.2018.126 SP - 933 EP - 940 PB - DGZfP e. V. AN - OPUS4-45495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günther, Martin A1 - Lorenzetti, A. A1 - Schartel, Bernhard T1 - Fire Phenomena of Rigid Polyurethane Foams N2 - Rigid polyurethane foams (RPUFs) typically exhibit low thermal inertia, resulting in short ignition times and rapid flame spread. In this study, the fire phenomena of RPUFs were investigated using a multi-methodological approach to gain detailed insight into the fire behaviour of pentaneand water-blown polyurethane (PUR) as well as pentane-blown polyisocyanurate Polyurethane (PIR) foams with densities ranging from 30 to 100 kg/m3. Thermophysical properties were studied using thermogravimetry (TG); flammability and fire behaviour were investigated by means of the limiting oxygen index (LOI) and a cone calorimeter. Temperature development in burning cone calorimeter specimens was monitored with thermocouples inside the foam samples and visual investigation of quenched specimens’ cross sections gave insight into the morphological changes during burning. A comprehensive investigation is presented, illuminating the processes taking place during foam combustion. Cone calorimeter tests revealed that in-depth absorption of radiation is a significant factor in estimating the time to ignition. Cross sections examined with an electron scanning microscope (SEM) revealed a pyrolysis front with an intact foam structure underneath, and temperature measurement inside burning specimens indicated that, as foam density increased, their burning behaviour shifted towards that of solid materials. The superior fire performance of PIR foams was found to be based on the cellular structure, which is retained in the residue to some extent. KW - Foam KW - Polyurethane KW - Fire behaviour KW - Flammability PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465577 DO - https://doi.org/10.3390/polym10101166 SN - 2073-4360 VL - 10 IS - 10 SP - 1166-1 EP - 1166-22 PB - MDPI AN - OPUS4-46557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schreier, Andy A1 - Liehr, Sascha A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Investigation on the influence of humidity on stimulated Brillouin backscattering in perfluorinated polymer optical fibers N2 - In this paper perfluorinated graded-index polymer optical fibers are characterized with respect to the influence of relative humidity changes on spectral transmission absorption and Rayleigh backscattering. The hygroscopic and thermal expansion coefficient of the fiber are determined to be CHE = (7.4 +/- 0.1) 10^-6 %r.h.^-1 and CTE = (22.7 +/- 0.3) 10^-6 K^-1, respectively. The influence of humidity on the Brillouin backscattering power and linewidth are presented for the first time to our knowledge. The Brillouin backscattering power at a pump wavelength of 1319 nm is affected by temperature and humidity. The Brillouin linewidth is observed to be a function of temperature but not of humidity. The strain coefficient of the BFS is determined to be CS = (146.5 +/- 0.9) MHz/% for a wavelength of 1319 nm within a strain range from 0.1 % to 1.5 %. The obtained results demonstrate that the humidity-induced Brillouin frequency shift is predominantly caused by the swelling of the fiber over-cladding that leads to fiber straining. KW - Brillouin KW - Polymer optical fibre KW - Humidity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465932 DO - https://doi.org/10.3390/s18113952 SN - 1424-8220 VL - 18 IS - 11 SP - 3952, 1 EP - 12 PB - MDPI CY - Basel, Switzerland AN - OPUS4-46593 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Uhlmann, E. A1 - Hinzmann, D. A1 - Kropidlowski, K. A1 - Meier, P. A1 - Prasol, L. A1 - Woydt, Mathias T1 - Increased tool performance with niobium carbide based cutting materials in dry cylindrical turning N2 - In the present work it was shown that in contrast to WC tools NbC cutting tools show constant material removal VW at increased cutting speed vc combined with a higher process reliability. KW - Niobium carbide (NbC) KW - Tungsten carbide (WC) KW - Tool wear KW - Cylindrical turning PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465968 DO - https://doi.org/10.1016/j.procir.2018.08.238 SN - 2212-8271 VL - 77 SP - 541 EP - 544 PB - Elsevier AN - OPUS4-46596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Wendland, Saskia A1 - Gaal, Mate T1 - Airborne testing of molded polymer compounds N2 - Modern and energy-efficient materials are essential for innovative designs for aerospace and automotive industries. Current technologies for rapid manufacturing such as additive manufacturing and liquid composite moulding by polymer Extrusion allow innovative ways of creating robust and lightweight constructions. Commercially available printing devices often use polylactide (PLA) or acrylonitrile butadiene styrene (ABS) as raw material. Therefore, parameters like the infill ratio, influencing the ability to resist mechanical stress, may have a beneficial impact on the lifetime of components. These manufacturing technologies require a good knowledge about materials and even adapted non-destructive testing technologies and methods. Airborne ultrasonic testing has beneficial advantages for testing those lightweight constructions. It is a contact-free testing method, which does not require a liquid couplant. Therefore, it allows fast test cycles without any unwanted alternations of the material properties due to interactions with any coupling liquid. This contribution deals with the characterisation of printed specimens based on PLA by using airborne ultrasound and presents the current edge of non-destructive testing and evaluation using airborne ultrasonic transducers. The specimens, manufactured by polymer extrusion, are printed as thin plates. The infill ratio, as well as the material thickness, were varied to model density imperfections with different geometric shapes and properties. For better understanding of the limits of airborne ultrasonic testing in transmission, we compared own-developed transducers based on different physical principles: on ferroelectrets, on the thermoacoustic effect, as well as a new type of transducers based on gas discharges. T2 - 10th International Symposium on NDT in Aerospace CY - Dresden, Germany DA - 24.10.2018 KW - Air-coupled ultrasonic testing KW - Polymer KW - Plasma acoustics KW - Gas discharges KW - Atmospheric pressure plasma PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465609 VL - 168 SP - Th.6.C.1, 1 EP - 7 AN - OPUS4-46560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Pérez Alonso, M. A1 - Albarrán Sanz, J. A1 - Dinkel, M. A1 - Heckel, Thomas A1 - Kotschate, Daniel A1 - Cabeza, Sandra A1 - Senaneuch, J. A1 - Heikkila, I. A1 - Toscanelli, O. T1 - A novel approach for rating fatigue-initiating inclusions in highly demanding steel (INCAFAT) N2 - INCAFAT project aimed to improve existing fatigue damage models by establishing the most suitable combination of measurement techniques to characterise harmful inclusion populations in highly demanding steels. The different inclusion assessments carried out confirm that, chemical composition, secondary metallurgy and manufacturing route affect content, nature, size and shape of inclusions. According to the FEM model, inclusions produce an alteration of the stress field in their surrounding region, which can promote a fatigue failure. Experimental work on fatigue testing has demonstrated that depending on the stressed direction fatigue failures in highly demanding steels could be produced by different types of inclusions. Fractography analyses confirmed that meso-inclusions harmful in fatigue cannot be rated by standard methods, nor 10 MHz ultrasonic testing (macro) or micro-cleanness assessments. The necessity of rating these meso-inclusions has led to critical evaluation of Extreme Value Analysis according to ASTM E2283-08 and the development of high frequency immersion ultrasonic testing. EVA methodology based on inclusion width can be applied reliably when principal stress is parallel to the rolling direction. On the contrary, if inclusions are testing in the elongated directions its fails. On the other hand, the guidelines and recommendations for high frequency ultrasonic testing have been compiled in a new European standard draft. This method based on focal beam probes and high-resolution devices is able to provide information on meso-inclusion distribution. KW - Material characterisation KW - Non-destructive testing KW - Ultrasonic testing KW - Cleanliness PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479219 UR - https://publications.europa.eu/en/publication-detail/-/publication/6bd25206-316a-11e8-b5fe-01aa75ed71a1/language-en/format-PDF/source-68610160 SN - 978-92-79-76985-6 DO - https://doi.org/10.2777/473350 SN - 1831-9424 SN - 1018-5593 SP - 1 EP - 154 AN - OPUS4-47921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wallau, Wilma A1 - Pirskawetz, Stephan A1 - Voland, K. A1 - Meng, Birgit T1 - Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models N2 - The susceptibility of concrete structures due to alkali–silica reaction (ASR) can be assessed by means of ASR concrete prism testing at 60 °C, according to RILEM AAR 4.1. There, expansion of concrete prisms indicates alkali-reactivity of the examined concrete mix. This work applies in situ expansion measurement to accelerated concrete prism testing. Automated measuring facilitates both storage without the usually necessary interruptions for manual measurement and acquisition of quasi-continuousexpansion data. A comparative experimental programme showed that conventional testing resulted in stronger expansion and leaching of alkalis than automated testing. Experimental simulation of interruptions, typically associated with manual measurements in conventional testing, could prove the influence of these cooling–heating cycles. Two phenomenological approaches, frequently used for describing reaction kinetics of ASR by linking it to expansion results from ASR-testing, were validated with continuous expansion data of three types of aggregate. Experimental expansion depicted s-shaped curves similar to them of the modelling approaches. However, strong swelling recorded in the beginning of the test was not covered by the model curves. Auxiliary measurement of acoustic emissions and ultrasonic velocity helped characterising mechanisms such as hydration and cracking, which also influence prism expansion. The proposed modification of the measurement procedure provides an extended basis to analyse expansion mechanisms. Regarding data for validation of ASR-expansion models, continuous expansion results are preferable to conventional test results. KW - Alkali–silica reaction KW - Accelerated concrete prism test KW - Automated expansion measurement KW - ASR modelling PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-455959 DO - https://doi.org/10.1617/s11527-018-1205-0 SN - 1359-5997 SN - 1871-6873 VL - 51 IS - 3 SP - 51 EP - 79 PB - Springer AN - OPUS4-45595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Küttenbaum, Stefan A1 - Taffe, A. A1 - Braml, T. A1 - Maack, Stefan ED - Alexander, M. G. ED - Beushausen, H. ED - Dehn, F. ED - Moyo, P. T1 - Reliability assessment of existing bridge constructions based on results of non-destructive testing N2 - The non-destructive testing methods available for civil engineering (NDT-CE) enable the measurements of quantitative parameters, which realistically describe the characteristics of existing buildings. In the past, methods for quality evaluation and concepts for validation expanded into NDT-CE to improve the objectivity of measured data. Thereby, a metrological foundation was developed to collect statistically sound and structurally relevant information about the inner construction of structures without destructive interventions. More recently, the demand for recalculations of structural safety was identified. This paper summarizes a basic research study on structural analyses of bridges in combination with NDT. The aim is to use measurement data of nondestructive testing methods as stochastic quantities in static calculations. Therefore, a methodical interface between the guide to the expression of uncertainty in measurement and probabilistic approximation procedures (e.g. FORM) has been proven to be suitable. The motivation is to relate the scientific approach of the structural analysis with real information coming from existing structures and not with those found in the literature. A case study about the probabilistic bending proof of a reinforced concrete bridge with statistically verified data from ultrasonic measurements shows that the measuring results fulfil the requirements concerning precision, trueness, objectivity and reliability. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - NDT KW - Concrete KW - Probabilistic reassessment KW - Bridge PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467898 DO - https://doi.org/10.1051/matecconf/201819906001 SN - 2261-236X VL - 199 SP - 06001, 1 EP - 9 PB - MATEC Web of Conferences AN - OPUS4-46789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Makris, Ruben A1 - Hille, Falk A1 - Thiele, Marc A1 - Kirschberger, D. A1 - Sowietzki, D. T1 - Crack luminescence as an innovative method for detection of fatigue damage N2 - In structural parts under vibrational loading fatigue cracks can initiate and grow, which can lead to structural failure. Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution, whereas crack luminescence coating realizes clear visibility of the entire crack formation. Fatigue causing cyclic tensile tests and examinations on special test bodies allowing control of the crack opening width demonstrate a high sensitivity of the coating. KW - Fatigue damage KW - Crack KW - Luminescence KW - Detection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446693 DO - https://doi.org/10.5194/jsss-7-259-2018 SN - 2194-8771 SN - 2194-878X VL - 7 SP - 259 EP - 266 PB - Copernicus Publications CY - Göttingen, Germany AN - OPUS4-44669 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maack, Stefan A1 - Villalobos, S. A1 - Scott, D. T1 - Validation of artificial defects for non-destructive testing measurements on a reference structure N2 - Non-destructive testing was established over the last decades as an important tool for assessing damages, material characterization and quality assurance in civil engineering. For example, Ground Penetrating Radar (GPR) can be used to scan large areas of concrete structures to determine the spatial position of the reinforcement. With the ultrasonic echo method, the thickness of concrete structures can be easily determined even if a high density of reinforcement is given. Various methods and processes have been developed for the validation of NDT procedures aiming at ensuring the quality of measurements in practical use. The Probability of Detection (POD) for example, is an available method to compare different technical devices with each other quantitatively regarding their performance. With this method, the best suited testing device for a specific inspection task under defined boundary conditions can be selected. By using the Guide to the Expression of Uncertainty in Measurement (GUM), it is possible to quantify the measurement uncertainty of an inspection procedure for a specific task. Another important aspect to improve the acceptance of Non-destructive testing methods is the development of reference specimens. Reference specimens serve for the calibration and further development of NDT methods under realistic conditions in different laboratories under the same conditions. A particular challenge here is the most realistic representation of a damage that can occur at building sites. Possible damages include for example horizontal and vertical cracks or honeycombs in concrete. Such a reference structure was built for the development of a new design of power plant constructions. Comparative studies on the manufacturing of realistic honeycombs and delaminations were carried out in advance on a test specimen. The results of this study are presented here. T2 - ICCRRR 2018 - Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 19.11.2018 KW - Zerstörungsfreie Prüfung KW - Nondestructive testing KW - Istzustandserfassung KW - Ultrasonic PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464497 DO - https://doi.org/10.1051/matecconf/201819906006 SN - 2261-236X VL - 199 SP - 1 EP - 9 PB - EDP Sciences CY - Les Ulis AN - OPUS4-46449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taffe, A. A1 - Küttenbaum, Stefan A1 - Maack, Stefan T1 - ZfPStatik - Messergebnisse rechenbar machen N2 - ZfPStatik bezeichnet die Verwendung von statistisch bewerteten Messergebnissen, die mit zerstörungsfreien Prüfverfahren im Bauwesen (ZfPBau) gewonnen werden und in statischen Berechnungen zum Nachweis der Tragfähigkeit verwendet werden. Dazu ist die Ermittlung der Messunsicherheit der Versuchsdaten auf der Basis des GUM (Guide to the Expression of Uncertainty in Measurement) der erste Schritt. Der statische Nachweis erfolgt durch Grenzzustandsgleichungen, die im Bauwesen angewandt werden. Diese müssen modifiziert werden, so dass jede Messgröße als Zufallsvariable in der Grenzzustandsgleichung vorhanden ist. Der statische Nachweis erfolgt mit probabilistischen Berechnungsmethoden aus der Zuverlässigkeitstheorie. Diese Vorgehensweise wird exemplarisch für den Standsicherheitsnachweis eines Plattenbalkenquerschnitts einer Stahlbetonbrücke auf Biegung angewandt. Auf die möglichen Schlussfolgerungen aus den probabilistischen Berechnungen wird abschließend kurz eingegangen. T2 - DGZfP-Fachtagung Bauwerksdiagnose 2018 CY - Berlin, Germany DA - 15.02.2018 KW - ZfP KW - ZfPBau KW - ZfPStatik KW - Zuverlässigkeitstheorie PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442266 UR - https://www.bauwerksdiagnose2018.de/Portals/bauwerksdiagnose2018/BB/20.pdf UR - https://www.bauwerksdiagnose2018.de SN - 978-3-940283-90-0 VL - BB 165 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-44226 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph A1 - Kruschwitz, Sabine T1 - Monitoring of the absolute water content in porous materials based on embedded humidity sensors N2 - Moisture transport monitoring may indicate the onset of deterioration in porous building materials Prior to damage occurring. Most moisture measurement systems provide only qualitative values, require extensive calibration, or are destructive. Thus, non-destructive and calibration-free monitoring Systems are required. Our approach of moisture monitoring is to embed sensors that measure the relative humidity. In our experiment, screed samples are monitored during the Hydration and evaporation process. Every test sample is equipped with 10 embedded sensors which measure the relative humidity across the sample thickness. Based on Hillerborg’s approach, the relative humidity is converted into the corresponding pore saturation. In our study, the free water is computed without knowledge of the Sorption isotherm. The free water in the pore system is predicted and validated. The predicted weight decrease corresponds conclusively to gravimetrically measured weights. The embedded sensors yield the absolute liquid water content and enable an experimental, non-destructive monitoring of liquid water in porous materials. KW - Moisture measurements KW - Porous materials KW - Embedded sensors KW - Partial pore saturation KW - Sorption isotherm PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453476 DO - https://doi.org/10.1016/j.conbuildmat.2018.05.044 SN - 0950-0618 VL - 177 SP - 511 EP - 521 PB - Elsevier AN - OPUS4-45347 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Algernon, A. A1 - Walther, A. A1 - Denzel, W. A1 - Ebsen, B. A1 - Feistkorn, S. A1 - Friese, M. A1 - Grosse, C. A1 - Kathage, S. A1 - Kessler, S. A1 - Köpp, Christian A1 - Krause, M. A1 - Maack, Stefan A1 - Schickert, M. A1 - Taffe, A. A1 - Timofeev, Juri A1 - Wilcke, M. A1 - Wolf, J. T1 - Qualitätssicherung und Validierung der Anwendung zerstörungsfreier Prüfungen von Stahlbetonbauteilen im Bauwesen N2 - Stahlbetontragwerke sind eine wichtige Konstruktionsweise im Bauwesen und ein wachsendes Anwendungsfeld für die Zerstörungsfreie Prüfung (ZfP). Zur Sicherung der Tragsicherheit, strukturellen Integrität, Bestimmung von Geometrien und zur Detektion konstruktiver Elemente wie z.B. Bewehrung, Verankerungen und Spannkanälen besitzen zerstörungsfreie Prüfverfahren in diesem Bereich inzwischen große Relevanz. Durch den bislang erreichten Fortschritt in der Forschung und Entwicklung haben moderne akustische und elektromagnetische Verfahren eine beachtliche Leistungsfähigkeit erreicht. Von Geräteherstellern sind diese in kommerziellen Produktserien umgesetzt worden und finden eine zunehmend breite Anwendung in der Praxis. In einigen anderen Anwendungsgebieten, in denen die ZfP bereits fester Bestandteil von Überwachungen ist, wie z.B. im Maschinenbau und insbesondere in der Kerntechnik und der Luftfahrt, existieren umfangreiche Qualitätssicherungssysteme für die konforme Anwendung und zuverlässige Einbeziehung der ZfP. Dem relativ jungen Entwicklungsstadium moderner ZfP für Stahlbetonbauteile entsprechend müssen solche Konzepte im Bauwesen erst noch entwickelt bzw. implementiert werden. Dementsprechend hat sich der Unterausschuss Qualitätssicherung (UA- S) des Fachausschusses ZfP im Bauwesen (ZfPBau) die Definition und Verbesserung der Qualität von ZfP-Anwendungen sowie insbesondere die verfahrensunabhängige Standardisierung von Prüfprozeduren und statistische Absicherung der Prüfergebnisse zum Ziel gemacht. Die aktuellen Arbeitsfelder beinhalten die Entwicklung praxisgerechter Konzepte für Prüfprozeduren und deren Erprobung in einem Ringversuch sowie die Konzeption von Testkörpern hinsichtlich unterschiedlicher Aspekte wie Parameterstudien, Validierung, Kalibrierung und Simulation. Dabei werden Ansätze anderer Branchen durchaus einbezogen, die Anpassung an die spezifischen Bedürfnisse und Gegebenheiten des Bauwesens wird jedoch als wesentlich angesehen und stellt somit eine wichtige Vorgabe dar. Da die Tätigkeiten nicht auf einzelne Verfahren begrenzt sind, müssen generelle Vorgehensweisen entwickelt werden, die sich auf die jeweiligen Verfahren konkretisieren lassen. Der Vortrag gibt hierzu erste Einblicke in die Arbeit des Ausschusses. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Zerstörungsfreie Prüfung KW - Beton KW - Qualitätssicherung KW - Validierung PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472417 SP - 1 EP - 9 AN - OPUS4-47241 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Vries, H. A1 - Jacobs, K. A1 - Egyedi, T. A1 - Eto, M. A1 - Fertig, S. A1 - Kanevskaia, O. A1 - Klintner, L. A1 - Koch, Claudia A1 - Mijatovic, I. A1 - Mirtsch, Mona A1 - Morone, P. A1 - Orviska, M. A1 - Riillo, C. A1 - Scaramuzzino, G. ED - Jacobs, K. T1 - Standardization: Towards an agenda for research N2 - Standardization research is a fairly new and is a still-evolving field of research, with possibly major practical ramifications. This article presents a summary of the authors’ subjective views of the most pressing research topics in the field. These include, among others, standards (e.g. incorporation of ethical issues), the potential impact of standards, the corporate management of standardization and legal issues like Intellectual Property Rights (IPR). In addition, gaps have been identified with a respect to a basic understanding of standardization, suggesting a need for better education in the field. KW - EURAS KW - Impact of standards KW - Intellectual property rights (IPR) KW - Research agenda KW - Standardization research PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467873 DO - https://doi.org/10.4018/IJSR.2018010104 SN - 2470-8542 VL - 16 IS - 1 SP - 52 EP - 59 PB - IGI Global AN - OPUS4-46787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Wang, Xin A1 - Herbrand, M. A1 - Müller, M. T1 - Processing ultrasonic data by coda wave interferometry to monitor load tests of concrete beams N2 - Ultrasonic transmission measurements have been used for decades to monitor concrete elements, mostly on a laboratory scale. Recently, coda wave interferometry (CWI), a technique adapted from seismology, was introduced to civil engineering experiments. It can be used to reveal subtle changes in concrete laboratory samples and even large structural elements without having a transducer directly at the place where the change is taking place. Here, several load tests until failure on large posttensioned concrete beams have been monitored using networks of embedded transducers. To detect subtle effects at the beginning of the experiments and cope with severe changes due to cracking close to failure, the coda wave interferometry procedures had to be modified to an adapted step-wise approach. Using this methodology, we were able to monitor stress distribution and localize large cracks by a relatively simple technique. Implementation of this approach on selected real structures might help to make decisions in infrastructure asset management. KW - Ultrasound KW - Concrete KW - Monitoring KW - Coda wave interferometry KW - Embedded transducers PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452328 DO - https://doi.org/10.3390/s19010147 SN - 1424-8220 VL - 19 IS - 1 SP - Article 147, 1 EP - 13 PB - MDPI CY - Basel AN - OPUS4-45232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -