TY - CONF A1 - Herrmann, Ralf A1 - Moortgat-Pick, A. A1 - Marx, S. ED - Helmerich, Rosemarie ED - Ilki, A. ED - Motavalli, M. T1 - Vibration Analysis of Structures using a Drone (UAV) based Mobile Sensing Platform N2 - The identification of the dynamic behavior of structures, like bridges and towers, is relevant to address multiple issues. In many cases the dynamic parameters should be acquired only once or at a frequency that doesn’t justify the installation of distinct vibration sensors for a long-term monitoring. To identify modal frequencies of a structure, a drone based mobile sensing platform has been implemented. This sensing platform measures the relative displacement be-tween the structure and the drone, which also shows a strong dynamic behavior under wind tur-bulences. By regarding the dynamic model of the drone and additional measurements at the dis-tance sensor the absolute movement of the structure can be estimated based on the measured relative distance. This time domain data is a suitable input for various operational modal analysis algorithms. The system has been used to identify the dynamic properties of test and real structure, like a 1.5 MW wind turbine tower. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) CY - Potsdam, Germany DA - 27.08.2019 KW - Modal Analysis KW - Drone KW - Vibration KW - Wind Turbines KW - Bridges PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492045 UR - http://data.smar-conferences.org/downloads/SMAR_2019_Proceedings.zip SN - 978-3-947971-07-7 SP - We.4.C.3 EP - 8 PB - German Society for Non-Destructive Testing (DGZfP e.V.) AN - OPUS4-49204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Menzel, F. A1 - Epperlein, N. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Bacterial adhesion on femtosecond laser-modified polyethylene N2 - In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced. KW - Bacterial adhesion KW - Laser-modified surface KW - Polyethylene KW - Laser-induced nanostructures KW - Biofilm PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492280 DO - https://doi.org/10.3390/ma12193107 VL - 12 IS - 19 SP - 3107 PB - MDPI CY - Basel, Schweiz AN - OPUS4-49228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Even, Morgane A1 - Hutzler, C. A1 - Wilke, Olaf A1 - Luch, A. T1 - Emissions of volatile organic compounds from polymer-based consumer products: comparison of three emission chamber sizes N2 - The ISO 16000 standard series provide guidelines for emission measurements of volatile organic compounds (VOCs) from building materials. However, polymer-based consumer products such as toys may also release harmful substances into indoor air. In such cases, the existing standard procedures are unsuitable for official control laboratories due to high costs for large emission testing chambers. This paper aims at developing and comparing alternative and more competitive methods for the emission testing of consumer products. The influence of the emission chamber size was investigated as smaller chambers are more suited to the common size of consumer products and may help to reduce the costs of testing. Comparison of the performance of a 203 l emission test chamber with two smaller chambers with the capacity of 24 l and 44 ml, respectively, was carried out by using a polyurethane reference material spiked with 14 VOCs during the course of 28 days. The area-specific emission rates obtained in the small chambers were always similar to those of the 203 l reference chamber after a few hours. This implies that smaller chambers can provide at least useful numbers on the extent of polymer-based consumer product emissions into indoor air, thereby supporting meaningful exposure assessments. KW - Comparison KW - Consumer products KW - Emission chamber KW - Reference material KW - Volatile organic compounds PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-493697 DO - https://doi.org/10.1111/ina.12605 VL - 30 IS - 1 SP - 40 EP - 48 PB - Wiley VCH-Verlag AN - OPUS4-49369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Ali, Naveed Zafar A1 - Maierhofer, Christiane A1 - Emmerling, Franziska T1 - Ettringite via Mechanochemistry: A Green and Rapid Approach for Industrial Application N2 - Here, we report on a first mechanochemical synthesis of ettringite, an important cement hydrate phase. The mineral compound ettringite ([Ca3Al(OH)6]2·(SO4)3·26H2O) occurs rarely in nature, but is common for cement-based materials. Ettringite has wide technical application in the ceramic and paper industry. However, its typical wet-chemical synthesis is cumbersome and produces waste water and CO2 emissions. Here, we investigate the first mechanochemical synthesis of ettringite for developing an easy and sustainable alternative for industrial application. The mechanosynthesis was monitored in situ by coupled synchrotron X-ray diffraction (XRD) and infrared thermography (IRT). The consumption of the reactants and the formation of the reaction product were monitored with time-resolved XRD. IRT showed the temperature increase based on the exothermic reaction. The reaction conversion was significantly improved changing the strategy of the mechanosynthesis from a one- to a two-step process. The latter included neat pregrinding of solid reactants followed by a delayed addition of the stoichiometric amount of water. Thus, an increase of reaction conversion from 34 to 94% of ettringite could be achieved. KW - XRD KW - Mechanochemistry KW - Ettringite KW - In situ PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479016 DO - https://doi.org/10.1021/acsomega.9b00560 SN - 2470-1343 VL - 4 IS - 4 SP - 7734 EP - 7737 PB - ACS Publications CY - Washington, DC AN - OPUS4-47901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haustein, T. A1 - Busweiler, Sabine A1 - Haustein, V. A1 - von Laar, C. A1 - Plarre, Rüdiger T1 - Laboratory breeding of Korynetes caeruleus (Coleoptera: Cleridae) for the biological of Anobium punctatum) (Coleoptera, Ptinidae) N2 - Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated. KW - Cultural heritage KW - Coleoptera KW - Korynetes caeruleus KW - Cleridae KW - Ptinidae KW - Anobium punctatum KW - Biological pest control KW - Life history data KW - Laboratory breeding KW - Wood protection PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494999 DO - https://doi.org/10.14411/eje.2019.038 SN - 1802-8829 VL - 116 SP - 362 EP - 371 PB - České Budějovice AN - OPUS4-49499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roveda, Ilaria A1 - Serrano Munoz, Itziar A1 - Haubrich, Jan A1 - Requena, Guillermo A1 - Madia, Mauro T1 - Investigation on the fatigue strength of AlSi10Mg fabricated by PBF-LB/M and subjected to low temperature heat treatments N2 - This work provides an investigation of the influence of low temperature heat treatments on the fatigue behavior of a PBF-LB AlSi10Mg alloy. Fatigue specimens are produced in form of round bars on a build platform preheated at 200 ◦C. The specimens have been tested in three different conditions: as-built, and after heat treatments at 265 ◦C for 1 h and 300 ◦C for 2 h. Prior to the fatigue testing, the defect distribution is analyzed by means of micro computed tomography. Subsequently, the peak over threshold method is successfully applied to provide a prediction of the size of killer defect. The defect population was of gas porosity type. No clear improvement of the fatigue performance is observed after the heat treatments. The fatigue strength predicted using fracture mechanics-based approaches is in good agreement with the experimental data. Among the studied approaches, short crack models provided the most conservative predictions. KW - PBF-LB/M AlSi10Mg KW - Fatigue strength KW - Defects KW - Kitagawa-Takahashi Diagram KW - Short Crack Models PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607071 DO - https://doi.org/10.1016/j.matdes.2024.113170 SN - 0264-1275 VL - 244 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-60707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Ghigo, Tea A1 - Rabin, Ira ED - Buzi, P. T1 - Detecting Early Medieval Coptic literature in Dayr Al-Anba Maqar, Between textual conservation and literary rearrangement: The case of Vat. Copt. 57 N2 - The study of the VAt.Copt. 57 at the Vatican Library. Codicological, palaeographical, textual and archaeometrical considerations. KW - Coptic KW - Archaeometry KW - Ink KW - Manuscripts PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494004 SN - 978-88-210-1025-5 SP - 77 EP - 83 PB - Biblioteca Apostolica Vaticana AN - OPUS4-49400 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, J. C. A1 - Battig, Alexander A1 - Velencoso, M. M. A1 - Pollok, D. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins N2 - The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin Metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs. KW - Phosphorus KW - Metathesis KW - Dendritic KW - Cone calorimeter KW - Fire test PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494535 DO - https://doi.org/10.3390/molecules24213901 SN - 1420-3049 VL - 24 IS - 21 SP - 3901 PB - MDPI AN - OPUS4-49453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strangfeld, Christoph A1 - Stolpe, Heiko A1 - Kruschwitz, Sabine ED - Schumann, R. T1 - Correlation between the electric impedance and the water layer thickness in partially saturated screed samples N2 - The moisture content of screed samples is monitored by means of embedded sensors. Relative humidity sensors and multi-ring-electrodes are used to measure the spatial moisture distribution during desorption. Based on the humidity data and the pore volume distribution, the moisture and the water layer thickness within the pore space are predicted. Slit shape as well as cylindrical pores are evaluated. Finally, the measured real part of the electrical impedance and the calculated water layer thickness are correlated. Based on the available data, a significant trend change of the impedance is documented at a water layer thickness of approximately 3 nm. This water layer thickness corresponds to a relative humidity of 88.3%. T2 - 10. CMM Tagung CY - Ettlingen, Germany DA - 10.10.2019 KW - Material moisture KW - Screed KW - Embedded sensors KW - Electric impedance KW - Water layer thickness PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494636 VL - 10 SP - 79 EP - 102 PB - CMM, Karlsruher Institut für Technologie CY - Karlsruhe AN - OPUS4-49463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schütz, R. A1 - Maragh, J. A1 - Weaver, J. A1 - Rabin, Ira A1 - Masic, A. T1 - The Temple Scroll: Reconstructing an ancient manufacturing practice N2 - The miraculously preserved 2000-year-old Dead Sea Scrolls, ancient texts of invaluable historical significance, were discovered in the mid-20th century in the caves of the Judean desert. The texts were mainly written on parchment and exhibit vast diversity in their states of preservation. One particular scroll, the 8-m-long Temple Scroll is especially notable because of its exceptional thinness and bright ivory color. The parchment has a layered structure, consisting of a collagenous base material and an atypical inorganic overlayer. We analyzed the chemistry of the inorganic layer using x-ray and Raman spectroscopies and discovered a variety of evaporitic sulfate salts. This points toward a unique ancient production technology in which the parchment was modified through the addition of the inorganic layer as a writing surface. Furthermore, understanding the properties of these minerals is particularly critical for the development of suitable conservation methods for the preservation of these invaluable historical documents. KW - Temple Scroll KW - Dead Sea Scrolls PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-495314 DO - https://doi.org/10.1126/sciadv.aaw7494 VL - 5 IS - 9 SP - 1 EP - 9 PB - AAAS AN - OPUS4-49531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -