TY - JOUR A1 - Tomiak, F. A1 - Schartel, Bernhard A1 - Wolf, M. A1 - Drummer, D. T1 - Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate) N2 - Aluminum tris (diethylphosphinate) (AlPi) is known to have an efficient flame-retardant effect when used in poly(butadiene terephthalates) (PBT). Additionally, better flame-retardant effects can be achieved through the partial substitution of AlPi by boehmite in multi-component systems, which have been shown to be an effective synergist due to cooling effects and residue formation. Although the potential of beneficial effects is generally well known, the influence of particle sizes and behavior in synergistic compositions are still unknown. Within this paper, it is shown that the synergistic effects in flammability measured by limiting oxygen index (LOI) can vary depending on the particle size distribution used in PBT. In conducting thermogravimetric analysis (TGA) measurements, it was observed that smaller boehmite particles result in slightly increased char yields, most probably due to increased reactivity of the metal oxides formed, and they react slightly earlier than larger boehmite particles. This leads to an earlier release of water into the system enhancing the hydrolysis of PBT. Supported by Fourier transformation infrared spectroscopy (FTIR), we propose that the later reactions of the larger boehmite particles decrease the portion of highly flammable tetrahydrofuran in the gas phase within early burning stages. Therefore, the LOI index increased by 4 vol.% when lager boehmite particles were used for the synergistic mixture. KW - Flame retardants KW - Aluminum diethylphosphinate KW - Boehmite KW - Poly(butadiene terephthalates) (PBT) KW - Mechanical properties PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509286 DO - https://doi.org/10.3390/polym12061315 SN - 2073-4360 VL - 12 IS - 6 SP - 1315 PB - MDPI AN - OPUS4-50928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kruschwitz, Sabine T1 - Challenges in Intelligent Computing for Non destructive testing in civil engineering – today and tomorrow N2 - A large amount of data and information is collected in the field of non-destructive testing (NDT) in civil engineering. The weakly structured data are usually evaluated with regard to specific testing tasks (e.g. geometry determination, damage localization, quality assurance). While the data offers great economic potential, i.e. to support construction planning, monitoring and maintenance processes, the evaluation is manual and case-by-case and therefore too inefficient for broader applications. We present recent visions and approaches how these large amounts of data need to be handled in the future and how we aim to make the acquired knowledge accessible to our stakeholders. Building on initiatives in materials research, we stress the importance of further research in the field of semantic data integration particularly motivate why an ontology is needed for the area of NDT in civil engineering. T2 - EG-ICE 2020 CY - Online meeting DA - 01.07.2020 KW - Data analysis KW - Non destructive testing KW - Computational engineering KW - AI PY - 2020 AN - OPUS4-50971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Santandrea, A. A1 - Vignes, A. A1 - Krietsch, Arne A1 - Brunello, D. A1 - Perrin, L. A1 - Laurent, A. A1 - Dufaud, O. T1 - Evaluating the explosion severity of nanopowders: International standards versus reality N2 - The maximum explosion overpressure and the maximum rate of pressure rise, which characterize thedust explosion severity, are commonly measured in apparatuses and under specific conditions defined byinternational standards. However, those standards conditions, designed for micropowders, may not befully adapted to nanoparticles. Investigations were conducted on different nanopowders (nanocellulose,carbon black, aluminum) to illustrate their specific behaviors and highlight the potential inadequacyof the standards. The influence of the sample preparation was explored. Various testing procedureswere compared, focusing on the dust cloud turbulence and homogeneity. Dust dispersion experimentsevidenced the importance of the characterization of the dust cloud after dispersion, due to the frag-mentation of agglomerates, using metrics relevant with nanoparticles reactivity (e.g. surface diameterinstead of volume diameter). Moreover, the overdriving phenomenon (when the experimental resultsbecome dependent of the ignition energy), already identified for micropowders, can be exacerbated fornanoparticles due to their low minimum ignition energy and to the high energy used under standardconditions. It was evidenced that for highly sensitive nanopowders, pre-ignition phenomenon can occur.Finally, during severe explosions and due to a too long opening delay of the ‘fast acting valve’, the flamecan go back to the dust container. KW - Dust explosions KW - Gas explosions KW - Minimum ignition temperature KW - Hybrid mixtures PY - 2020 DO - https://doi.org/10.1016/j.psep.2020.04.011 VL - 138 SP - 279 EP - 291 PB - Elsevier B.V. AN - OPUS4-50944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Patrick P. T1 - Aerial Robot Olfaction - A Summary and Survey from BAM Perspective N2 - This presentation gives an introduction to the gas-sensitive aerial robots developed at BAM, including various application examples in the field of mobile robot olfaction: gas source localization and gas distribution mapping. T2 - Harvard University School of Engineering and Applied Sciences (SEAS)/Earth and Planetary Sciences (EPS) - Martin Group Seminar CY - Online meeting DA - 11.06.2020 KW - Mobile Robot Olfaction KW - Localization of gas sources KW - UAV KW - Tomographic reconstruction of gas plumes KW - Tunable Diode Laser Absorption Spectroscopy (TDLAS) PY - 2020 AN - OPUS4-50916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Palis, Stephan A1 - Sträubig, Felix A1 - Voigt, Sascha A1 - Knaust, Christian T1 - Experimental investigation of the impact of water mist on high-speed non-premixed horizontal methane jet fires N2 - In this paper, the influence of a fixed water mist firefighting system on a high-speed non-premixed horizontal methane jet fire is investigated with focus on its effect on temperatures and heat load of the jet fire and on ist surroundings. Six tests are performed in which gas is released out of an orifice with a diameter of 1 mm and a release pressure of up to 186 bar. In addition to temperature and radiation measurements, the release pressure, gas mass flow rate and exhaust gas concentrations are detected to determine the heat release. Video and IRanalysis are used to evaluate the interactions between jet fire and water mist. The experiments show, that water mist reduces the temperatures inside the jet fire flow field and its radiative heat flux. It can lower the Risk of ignition of adjacent surfaces and materials, as temperatures fall below autoignition temperatures of common materials like plastics. Although water mist does not extinguish the fire, it has an impact on the energy release by reducing combustion efficiency due to heat exchange with the water mist and oxygen displacement. KW - Fixed firefighting system KW - Jet fire KW - Water mist KW - Fire test KW - Methane KW - Supersonic flow PY - 2020 DO - https://doi.org/10.1016/j.firesaf.2020.103005 VL - 114 SP - 103005 PB - Elsevier Ltd. AN - OPUS4-50963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Häßler, Dustin A1 - Mund, M. T1 - Bewertung des Feuerwiderstandes von Stahlkonstruktionen mit reaktiven Brandschutzsystemen unter Berücksichtigung des Alterungsverhaltens N2 - Vorstellung des Arbeitsstands im Projekt 20470N (BAM Vh 7350). T2 - 98. Sitzung des Arbeitsausschusses Brandschutz CY - Hamburg, Germany DA - 09.11.2018 KW - Reaktive Brandschutzsysteme KW - Dauerhaftigkeit KW - Brandschutz KW - Stahl PY - 2018 AN - OPUS4-49793 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epple, Niklas T1 - Monitoring of bridges with coda waves - first steps towards an imaging strategy N2 - Monitoring of concrete structures is of utmost importance in maintenance and preservation of infrastructure. As a part of the DFG research group CoDA (Concrete Damage Assessment by Coda Waves), the works within this PhD project aim for identification of damage sensitive parameters extracted from ultrasonic measurements obtained with embedded sensors, the determination of environmental (reversible) influences on the signal and the localisation of damaged areas. The main technique used for the detection of changes in the monitored material is the so-called Coda Wave Interferometry (CWI). It uses the later part of the ultrasonic recording for the detection of small changes in the sensed area and the calculation of a relative velocity change. Using this technique we can show that we are able to detect changes in concrete temperature with ultrasound measurements. This enables temperature correction for ultrasound monitoring with embedded sensors. The crucial point for imaging and localisation with coda waves is the calculation of the so-called sensitivity kernels. We propose the application of numerical wave simulations for the kernel calculations instead of the commonly used diffusivity equation. Using finite-difference wave modelling code from our DFG project partners we are able to calculate those Kernels and first results are shown in this presentation. The major task for the second year will be the development and implementation of the inversion algorithm as well as the preparation of validation experiments. T2 - Doktorandenseminar BAM Abt. 8 CY - Berlin, Germany DA - 30.03.2020 KW - Ultrasound KW - Non-destructive testing KW - Numerical modelling KW - Structural health monitoring PY - 2020 AN - OPUS4-50624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Wosniok, Aleksander ED - Werneck, M.M. ED - da Silva Barros Allil, R.C T1 - POF Sensors for Structural Health Monitoring N2 - The ever more ambitious strategic goals of meeting the requirements in ensuring technical safety and security of civil structures have resulted in flourishing development of innovative structural health monitoring (SHM) technologies for early damage diagnosis and prognosis. At the same time, implementing SHM systems provides tangible economic benefits derived from lower life-cycle costs associated with reduction in the maintenance, repair and insurance expenses. Due to the large size and harsh environmental conditions common to most civil structures, the broad range of favorable physical-mechanical properties of POFs allow for customized monitoring solutions for a wide variety of applications. In addition to common SHM-related advantages of optical fibers including their electromagnetic immunity, small size, lightweight as well as spark-free and non-conductive characteristics, POFs offer better bending and fracture resistance then their glass-counterparts. Particularly, the improved robustness of POFs, their ease of handling, low Young’s Modulus and high elastic limit of 10% compared to 1% in silica glass [1] are relevant to practical applications. Depending on the composition, dopants, drawing process and geometry [2], strain measurement up to 45% [3] or even above 100% [4,5] has been demonstrated with standard POFs. Therefore, the dominant market expected for POF sensors includes monitoring of high-strain-rate deformations in earthwork structures, crack detection in concrete and masonry structures [6] or overstressing in high-rise steel structures exposed to moisture, corrosion, leakage, fatigue, vibration, fire, overflow, earthquake and intentional damage. For fracture monitoring within concrete structures, the sensory usage of POFs becomes especially favorable since the extremely alkaline environment of concrete mixtures is well known to be corrosive to standard silica glass optical fibers (GOFs) [1,7]. Most of advanced distributed sensing techniques are commonly based on Rayleigh backscatter reflectometry using commercially available multimode (MM) POFs. Such typical MM POFs range from a step-index (SI) poly(methyl methacrylate) (PMMA) POF having a core diameter of 1 mm to a low-loss graded-index (GI) perfluorinated (PF) POF based on poly(perfluorobutenyl-vinylether) also known as CYTOP [8] with a 50 µm core diameter. The relatively low optical attenuation value of 30 dB/km at 1.3 µm [9,10] makes PFGI POFs also interesting for distributed Brillouin sensing [11-14]. Compared to GOFs, PFGI POFs offer better potential for temperature measurement and have comparably low theoretical attenuation limit [15]. Therefore, POF-based distributed Brillouin sensing is expected to play an important role in the future of SHM, especially at high-strain ranges. The significance of the Brillouin measurment technique can be also enhanced by further development of the single-mode (SM) POFs which are still subject of research and are used for coherent detection techniques [6]. Furthermore, SM PMMA POFs have been characterized in a Mach-Zehnder interferometer setup for strain values up to 15.8% [16,17]. The current development of SM perfluorinated and microstructured POFs (mPOFs) represents an immense promise for quasi-distributed dynamic measurement at high strain levels based on fiber Bragg grating (FBG) technology. While SM mPOFs with optical losses of about 1 dB/m can be fabricated [6], the SM PF POFs presented by Zhou et al. feature low attenuation of even less than 0.2 dB/m in the wavelength range of 1.41 µm to 1.55 µm [18]. At the same time, the SM PF POFs have the potential for improved thermal stability compared to their PMMA counterparts [19]. This whole chapter provides a comprehensive overview on current POF-based sensing principles and SHM technologies, highlighting their diverse applications in civil engineering structures. In the application-related context, close attention is paid to the development of smart sensor-based geotextiles and geogrids. Such geosynthetics-integrated distributed POF sensors have proven to be a promising solution for two- or even tree-dimensional monitoring of critical high mechanical deformations in both geotechnical and masonry structures. Moreover, geosynthetics in the form of nonwoven geotextiles as well as polymer-based geogrids used as carrier materials for POF sensors enable optimized load transfer from the monitored structure to the measuring fiber without losing their original functionality. In other words, smart geosynthetics provide a cost-efficient dual solution for, on the one hand, well-established increase of structure stability and decrease of erosion effects, on the other hand, early-warning and detection capabilities in the prevention and elimination of potential hazards and lasting damages. KW - Plastic Optical Fiber Sensor KW - OTDR KW - Brillouin Sensing KW - Interferometric Sensor KW - FBG KW - Long Period Grating KW - Smart Geosynthetics PY - 2020 SN - 978-1-13829-853-8 SP - 267 EP - 283 PB - CRC Press Taylor & Francis Group CY - Boca Raton, FL, USA AN - OPUS4-50561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mundra, Shishir A1 - Prentice, D. P. A1 - Bernal, S. A. A1 - Provis, J. L. T1 - Modelling chloride transport in alkali-activated slags N2 - The service-life of steel-reinforced concrete structures is primarily determined by the ability of the concrete cover to resist chloride ingress. With limited literature available on the ingress of chloride into alkali-activated slags (AAS) under service conditions, it is critical that this is described by appropriate models. This paper describes an interactive software framework to relate chloride ingress into AAS with the chemistry of the concrete cover, by considering the chloride binding capacity and porosity of the binder as a function of time, based on thermodynamic calculations of the phase assemblage as a function of slag and activator composition. This provides a major step towards developing the ability to predict the ingress of chlorides in alkali-activated concretes from a sound theoretical basis, which is essential in providing confidence in the durability of these materials in essential infrastructure applications. KW - Thermodynamic calculations KW - Alkali activated cement KW - Durability KW - Diffusion KW - Chloride PY - 2020 DO - https://doi.org/10.1016/j.cemconres.2020.106011 VL - 130 SP - 106011 PB - Elsevier Ltd. AN - OPUS4-50423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Multifunktionale Geokunststoffe - nachhaltige Zustandsüberwachung durch ortsaufgelöste faseroptische Sensoren N2 - Vorstellung von Entwicklungsarbeiten zum Thema sensorbasierte Geokunststoffe mit integrierten faseroptischen Sensoren. T2 - 14. Bautextilien-Symposium BAUTEX 2020 CY - Chemnitz, Germany DA - 29.01.2020 KW - Intelligente Geokunststoffe KW - Sensorbasierte Geokunststoffe KW - Faseroptischer Sensor KW - Ortsverteilter Sensor PY - 2020 AN - OPUS4-50321 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Morys, Michael A1 - Häßler, Dustin A1 - Krüger, Simone A1 - Schartel, Bernhard A1 - Hothan, Sascha T1 - Beyond the standard time-temperature curve: Assessment of intumescent coatings under standard and deviant temperature curves N2 - Nowadays there are intumescent coatings available for diverse applications. There is no established assessment of their protection performance besides the standard time-temperature curve, but natural fire scenarios often play an important role. A reliable straightforward performance-based assessment is presented. The effective thermal conductivity per thickness is calculated based on intermediate-scale fire tests. The optimum thermal insulation, the time to reach it, and the time until contingent failure of the coating are used for an assessment independent of the heating curve. The procedure was conducted on four different commercially intumescent coatings for steel construction, one solvent-based, one waterborne, one epoxy-based, and a bandage impregnated with a waterborne coating. The performance was studied under four different but similar shaped heating curves with different maximum temperatures (standard time-temperature curve, hydrocarbon curve and two self-designed curves with reduced temperature). The thermal protection performance is crucially affected by the residue morphology. Therefore, a comprehensive morphology analysis, including micro-computed tomography and scanning electron microscopy, was conducted on small-scale residues (7.5 x 7.5 cm2). Two different types of inner structures and the residue surface after different heat exposures were discussed in terms of their influence on thermal protection performance. KW - Intumescence KW - Coating KW - Computed tomography KW - Small scale KW - Heating curves KW - Residue morphology PY - 2020 DO - https://doi.org/10.1016/j.firesaf.2020.102951 SN - 0379-7112 VL - 112 SP - 102951 PB - Elsevier Ltd. AN - OPUS4-50334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Martin A1 - Wu, Dejian A1 - Zhao, P. A1 - Tan, X. A1 - Huang, W. A1 - Qianc, X. T1 - Minimum explosion concentrations of coal dusts with CH4/H2/CO below the gas lower explosion limit N2 - A 20-L spherical explosion chamber was used to investigate the explosion characteristics of dust clouds in air with the presence of flammable gas which is lower than its lower explosion limit (LEL). including minimum explosion concentration (MEC) of dust. Explosion pressure (Pex) and explosion pressure rise (dp/dt)ex). Two dust samples (anthracite coal, bituminous coal) and were three flammable gases (CH4, H2 and CO) were tested. Experimental results showed that the explosion of hybrid mixtures occurs when both dust and gas concentrations are lower than the LEL/MEC of the single substances. Meanwhile. all flammable gases with different volume fractions have distinct effects on the MEC. Pex and (dp/dt)ex of the dust samples. With the increase of the flammable gas concentration. either the Pex and (dp/dt)ex increase or the MEC decreases for all the hybrid mixtures of both two dust samples. At the same concentration of coal dusts. the addition of CH4 promotes higher explosion risks than the other two flammable gases. The distribution of (dp/dt)ex is quite different with the restricted area defined by empirical formulas. These results improve our understanding of the explosion behaviour and the explosion risk of hybrid dust-gas mixtures in air. KW - Dust explosions KW - Gas explosions KW - Minimum explosible concentration KW - Lower explosion limit KW - Hybrid mixtures PY - 2020 DO - https://doi.org/10.1016/j.fuel.2019.116401 SN - 0032-5910 VL - 260 SP - UNSP 116401 PB - Elsevier Sci. Ltd. AN - OPUS4-49956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Szypkowski, Marko ED - Bartmann, H. T1 - Taucher-Handbuch, Technik, Tauchgeräte- Bauteile und Baugruppen für Leichttauchgeräte, Kap. Flaschenventile N2 - Darstellung der Gefahren und und Hinweis auf die anzuwendenden Normen bei der Wartung bei Sauerstoffventilen im Bereich des Atemschutz KW - Atemschutz KW - Gasflaschenventil KW - Sauerstoff PY - 1993 SN - 978-3-609-75380-5 VL - 2020 SP - 51 EP - 51 PB - Storck Verlag CY - Landsberg am Lech ET - 108 AN - OPUS4-50827 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Dejian A1 - Schmidt, Martin A1 - Tan, X. A1 - Zhao, P. A1 - Huang, W. A1 - Qian, X. T1 - Minimum ignition temperature of carbonaceous dust clouds in air with CH4/H-2/CO below the gas lower explosion limit N2 - Godbert-Greenwald furnace was used to investigate the minimum ignition temperature of dust clouds (MITC) in air with the presence of flammable gas which is lower than its lower explosion limit (LEL). Three flammable gases (CH4, H2 and CO) and three carbonaceous dusts (anthracite coal, bituminous coal and sweet potato starch) were tested. Results showed that all flammable gases have distinct effects on the MITC of the dust samples and volatile matter content of dust plays an important role during the ignition process. Specifically, the MITC of anthracite coal dust decreased from 610 °C to 560 °C, 580 °C and 570 °C with 3% CH4, 3% CO and 2.5% H2, respectively. Moreover, a heterogeneous ignition mechanism model was proposed to verify the equally global ignition characteristic between hybrid anthracite coal-CxHy mixture and bituminous coal. All three gases had an ignorable effect on the MITC of starch dust considering the experimental error. The presence of CO and H2 slightly promoted the ignition of bituminous coal dust, but the addition of CH4 showed a distinct concentration effect on the MITC of bituminous coal: the MITC decreased with 1% CH4 while increased with 2% and 3% CH4. This negative-effect of flammable gases at such low concentrations on ignition temperature of bituminous coal dusts was found for the first time. Furthermore, the presence of the 2nd flammable gas had a smaller effect on the MITC of dust samples with a higher volatile content, resulted from the competition of heterogeneous and homogeneous ignition mechanisms. KW - Dust explosions KW - Gas explosions KW - Minimum ignition temperature KW - Hybrid mixtures PY - 2020 DO - https://doi.org/10.1016/j.fuel.2019.116811 SN - 0016-2361 VL - 264 SP - 116811 PB - Elsevier Ltd. AN - OPUS4-50856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -