TY - CONF A1 - Schulze, S. A1 - Krause, Martin A1 - Mayer, K. A1 - Redmer, Bernhard A1 - Wiggenhauser, Herbert T1 - Grouting defects localized by ultrasonic testing including phase evaluation N2 - Grouting defects, e.g. in post-tensioned structures or piped anchors may be identified by ultrasonic imaging. Since several years experiences are carried out with false color displayed phase values, which enable distinct localization of ungrouted regions. In this contribution we report on progress in localizing grouting defects in tendon ducts, when they are only partly grouted and the unfilled part is not orientated into the direction of the measuring surface. This is frequently the case e.g. for box girder structures. Düring the project specimens containing different types of grouting faults are investigated in Order to optimize measuring and evaluation techniques. A handheld linear array System (commercially available) is applied for fast 2D-measurement and subsequent phase sensitive 3D-imaging (new Software development). In a large concrete wall specimen tendon ducts and real prestressing Systems containing grouting defects were built in. The ducts are partly covered by non prestressed reinforcement bars in order to investigate its disturbing influence. These included objects were investigated afterwards with the described methods. We report on large area measuring results, which were partly verified by y-radiography. In the frame of practical application results of measuring the position and extend of a blockade within a posttensioned structure are presen ted. T2 - SMT 2014 - NDE/NDT for highways and bridges - Structural materials technology CY - Washington, DC, USA DA - 25.08.2014 KW - Ultraschallecho-Verfahren KW - Spannbeton KW - Phasenauswertung PY - 2014 SN - 978-1-57117-342-3 SP - 321 EP - 328 AN - OPUS4-32846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fiedler Bremer, C. A1 - Scholz, R. A1 - Myslicki, S. A1 - Starke, P. A1 - Boller, C. A1 - Walther, F. A1 - Krause, Martin T1 - NDT-based characteriazation of timber and vulcanized fiber for civil infrastructure N2 - The paper addresses beech wood as well as vulcanized fiber and discusses the results obtained when using acoustic emission and thermography as non-destructive testing techniques along tensile and load increase fatigue tests to characterize the wooden material’s behavior under increasing fatigue loads to get enhanced information regarding the fatigue behavior of both materials. Reference is mainly made to the materials’ anisotropic and microstructural behavior and what implications this has with respect to the materials’ strength. The influence of moisture is discussed, as well as parameters that may deserve monitoring in the sense of structural health monitoring to be applied in timber structures in general. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Ermüdung KW - Belastungsversuch KW - Thermographie KW - ZfP KW - Timber PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346377 UR - https://www.ndt.net/?id=18419 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 11 PB - NDT.net CY - Kirchwald AN - OPUS4-34637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Calus, S. A1 - Kityk, A.V. A1 - Borowik, L. A1 - Lefort, R. A1 - Morineau, D. A1 - Krause, Christina A1 - Schönhals, Andreas A1 - Busch, M. A1 - Huber, P. T1 - High-resolution dielectric study reveals pore-size-dependent orientational order of a discotic liquid crystal confined in tubular nanopores N2 - We report a high-resolution dielectric study on a pyrene-based discotic liquid crystal (DLC) in the bulk state and confined in parallel tubular nanopores of monolithic silica and alumina membranes. The positive dielectric anisotropy of the DLC molecule at low frequencies (in the quasistatic case) allows us to explore the thermotropic collective orientational order. A face-on arrangement of the molecular discs on the pore walls and a corresponding radial arrangement of the molecules is found. In contrast to the bulk, the isotropic-to-columnar transition of the confined DLC is continuous, shifts with decreasing pore diameter to lower temperatures, and exhibits a pronounced hysteresis between cooling and heating. These findings corroborate conclusions from previous neutron and x-ray-scattering experiments as well as optical birefringence measurements. Our study also indicates that the relative simple dielectric technique presented here is a quite efficient method in order to study the thermotropic orientational order of DLC-based nanocomposites. PY - 2015 DO - https://doi.org/10.1103/PhysRevE.92.012503 SN - 1539-3755 SN - 1063-651X VL - 92 IS - 1 SP - 012503-1 EP - 012503-6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-33813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griebenow, Werner A1 - Werthmann, Barbara A1 - Treu, Dieter A1 - Hörn, K. A1 - Krause, S. T1 - Zur Identifizierung von Tinten auf alten Handschriften PY - 1983 SN - 0025-1445 SN - 0342-3719 VL - 89 IS - 3 SP - 208 EP - 212 PB - Callwey CY - München AN - OPUS4-38963 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Samokrutov, A A1 - Mayer, K A1 - Krause, Martin A1 - Alekhin, S. G. A1 - Elkin, V T1 - Large aperture ultrasonic system for testing thick concrete structures N2 - A Large Aperture UltraSonic system (LAUS) has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually on the surface to achieve optimal ultrasonic condition, e.g. to avoid rebars. For the generation of vacuum, air pressure is supplied to each unit through an air hose. The twelve units define an aperture which is necessary for fast reconstruction of the subsurface structure. The well-known SAFT (Synthetic Aperture Focusing Technique) algorithm has been adopted to this situation, where the individual LAUS units form a linear aperture with not necessarily equidistant spacing between the units. The exact geometrical position of the units, which are individually marked with retroreflective labels, is determined using photographs and image processing. All transducers are synchronized and work either as transmitter or receiver. A full scan consists of 12 * 11 recordings, where each unit acts as transmitter once and all others as receivers. An electronic sub-unit on the back of the ultrasonic device holds the battery and handles data acquisition, synchronization and data communication. A computer is used as base unit which communicates with each LAUS unit for control and data acquisition, the synchronization is performed by a radio modem that uses a special algorithm similar to a digital PLL (phase locked loop). No wire connections are necessary between the units and the base system. The LAUS system is designed to investigate concrete structures with thicknesses in excess of 2 m, depending on the acoustic condition of the object under investigation. Highly reinforced concrete may have less penetration depth. The LAUS provides quasi real time imaging, once the transducers are put in place and the data has been acquired. First measurements on a foundation slab confirm, that the system can register ultrasonic echoes from the back wall at 4 m distance. KW - Ultrasound "Large Aperture" NDT Concrete PY - 2017 DO - https://doi.org/10.1061/(ASCE)IS.1943-555X.0000314 SN - 1076-0342 SN - 1943-555X VL - 23 IS - 1 SP - B4016004-1 EP - B4016004-9 PB - American Society of Civil Engineers (ASCE) CY - Reston, VA 20191-4400 USA AN - OPUS4-39372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaudelka, Sven A1 - Hofmann-Böllinghaus, Anja A1 - Hauswaldt, S. A1 - Krause, U. T1 - Auswirkung von Zündquellen und Systembeschaffenheit auf das Brandverhalten EPS-basierter Wärmedämm-Verbundsysteme N2 - Gegenstand des Aufsatzes ist die experimentelle Untersuchung der Auswirkungen verschiedener Zündquellen sowie der Systembeschaffenheit auf das Brandverhalten EPS-basierter Wärmedämm-Verbundsysteme (WDVS). Dazu wurden Brände ausgewertet, die mit EPS-basierten WDVS in Verbindung stehen. Ergebnis dieser Auswertung war, dass nicht wie bisher angenommen der Brand in dem Gebäude (z. B. der Wohnungsbrand), sondern vielmehr der Brand außerhalb des Gebäudes, insbesondere der des Abfallbehälters, das häufigste und kritischste Brandszenario für EPS-basierte WDVS darstellt. Daraufhin wurden an der BAM Bundesanstalt für Materialforschung und -prüfung Brandversuche in der Single Burning Item-Prüfeinrichtung (SBI) an nicht intakten EPS-basierten WDVS-Ausschnitten durchgeführt. Mit zunehmender Beschädigungsgröße und -tiefe stieg die vom System freigesetzte Wärmefreisetzungsrate an. Zusätzlich werden Brandversuche eines Sockelbrandszenarios mit einer abfallbehälteräquivalenten Brandlast vorgestellt. Aus den Brandversuchen werden Empfehlungen zur Verbesserung der Systemsicherheit abgeleitet.------------------------------------------------------------------------------------------------------------------------------------------------- The influence of different ignition sources and conditions of the systems on the fire behaviour of external thermal insulating systems (ETICS) have been investigated experimentally. As a basis of the investigations real cases with EPS based ETICS have been analysed. The analysis showed that the fire in front of the building is the most common and critical fire scenario for these systems. These fires are often caused by waste containers. This result contradicts the former common assumption that the fire inside the building is the most critical fire scenario for ETICS. Intermediate scale experiments in the Single Burning Item (SBI) test apparatus have been performed at BAM with ETICS specimens. The render of the systems was partially damaged. The measured heat release rate of the specimens increased significantly with size and depths of the damages. Additionally results of large scale experiments with a waste container equivalent ignition source are presented and recommendations to enhance fire safety of these systems are given. KW - Fassaden KW - Wärmedämm-Verbundsystem (WDVS) KW - Expandiertes Polystyrol (EPS) KW - Brandverhalten von Baustoffen KW - Bemessungsbrandszenario KW - Sockelbrand KW - Abfallbehälter KW - ET/CS KW - External thermal insulation composite system KW - Expanded polystyrene KW - Waste containers KW - Released heat rate KW - Plinths-based fire scenario KW - Single burning item test KW - Single Burning Item-Prüfeinrichtung (SBI) KW - Wärmefreisetzungsrate KW - DIBt-Empfehlung KW - Façades KW - Brandschutz - Fire protection engineering PY - 2015 DO - https://doi.org/10.1002/bapi.201510023 SN - 0171-5445 SN - 1437-0980 VL - 37 IS - 4 SP - 205 EP - 212 PB - Ernst CY - Berlin AN - OPUS4-33835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hachenberger, Y. U. A1 - Rosenkranz, Daniel A1 - Kromer, C. A1 - Krause, B. C. A1 - Dreiack, N. A1 - Kriegel, F. L. A1 - Kozmenko, E. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Bierkandt, F. S. A1 - Laux, P. A1 - Panne, Ulrich A1 - Luch, A. T1 - Nanomaterial Characterization in Complex Media - Guidance and Application N2 - A broad range of inorganic nanoparticles (NPs) and their dissolved ions possess a possible toxicological risk for human health and the environment. Reliable and robust measurements of dissolution effects may be influenced by the sample matrix, which challenges the analytical method of choice. In this study, CuO NPs were investigated in several dissolution experiments. Two analytical techniques (dynamic light scattering (DLS) and inductively-coupled plasma mass spectrometry (ICP-MS)) were used to characterize NPs (size distribution curves) time-dependently in different complex matrices (e.g., artificial lung lining fluids and cell culture media). The advantages and challenges of each analytical approach are evaluated and discussed. Additionally, a direct-injection single particle (DI sp)ICP-MS technique for assessing the size distribution curve of the dissolved particles was developed and evaluated. The DI technique provides a sensitive response even at low concentrations without any dilution of the complex sample matrix. These experiments were further enhanced with an automated data evaluation procedure to objectively distinguish between ionic and NP events. With this approach, a fast and reproducible determination of inorganic NPs and ionic backgrounds can be achieved. This study can serve as guidance when choosing the optimal analytical method for NP characterization and for the determination of the origin of an adverse effect in NP toxicity. KW - Nanon KW - Characterization KW - SpICP-MS KW - Matrix KW - Dissolution PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572138 DO - https://doi.org/10.3390/nano13050922 VL - 13 IS - 5 SP - 1 EP - 19 AN - OPUS4-57213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Amano, K. A1 - Hahn, S. A1 - Tschirschwitz, Rico A1 - Rappsilber, Tim A1 - Krause, U. T1 - An Experimental Investigation of Thermal Runaway and Gas Release of NMC Lithium-Ion Pouch Batteries Depending on the State of Charge Level N2 - In this study, 19 experiments were conducted with 25 pouch cells of NMC cathode to investigate thermal runaway and the release of gases from lithium-ion batteries (LIBs). Single cells, double cells, and a four-cell battery stack were forced to undergo thermal runaway inside an air-tight reactor vessel with a volume of 100 dm3 . The study involved two series of tests with two types of ignition sources. In the Series 1 tests, a heating plug was used to initiate thermal runaway in LIBs in the ranges of 80–89% and 90–100% SOC. In the Series 2 tests, a heating plate was used to trigger thermal runaway in LIBs in the ranges of 30–50%, 80–89%, and 90–100% SOC. Thermal runaway started at an onset temperature of 344 ± 5 K and 345 K for the Series 1 tests and from 393 ± 36 K to 487 ± 10 K for the Series 2 tests. Peak reaction temperatures ranged between 642 K and 1184 K, while the maximum pressures observed were between 1.2 bar and 7.28 bar. Thermal runaway induced explosion of the cells and lead to a rate of temperature increase greater than 10 K/s. The amounts of gases released from the LIBs were calculated from pressures and temperatures measured in the reactor. Then, the gas composition was analyzed using a Fourier transform infrared (FTIR) spectrometer. The highest gaseous production was achieved at a range of 90–100% SOC and higher battery capacities 72 L, 1.8 L/Ah (Series 1, battery stack) and 103 L, 3.2 L/Ah (Series 2, 32 Ah cell)). Among the gases analyzed, the concentration of gaseous emissions such as C2H4 , CH4 , and C2H6 increased at a higher cell capacity in both series of tests. The study results revealed characteristic variations of thermal behavior with respect to the type of ignition source used. KW - Lithium-ion batteries KW - Battery KW - Pouch cell KW - NMC Cathode KW - Thermal runaways PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548601 DO - https://doi.org/10.3390/batteries8050041 VL - 8 IS - 5 SP - 1 EP - 16 PB - MDPI CY - Basel, Switzerland AN - OPUS4-54860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zakel, S. A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Gabel, D. A1 - Hirsch, W. A1 - Kleinert, J. A1 - Krause, U. A1 - Krietsch, Arne A1 - Meistes, J. A1 - Sachtleben, A. A1 - Schmidt, Martin T1 - Sicherheitstechnische Kenngrößen des Explosionsschutzes von hybriden Stoffgemischen - Normungsfähige Bestimmungsverfahren N2 - In diesem Verbundvorhaben werden standardisierte Messverfahren für hybride Gemische erarbeitet, die der Bestimmung sicherheitstechnischer Kenngrößen des Explosionsschutzes dienen. Unter einem hybriden Gemisch wird dabei ein mehrphasiges System aus Brenngas oder brennbarem Dampf, sowie Luft und brennbarem Staub verstanden. Die Veröffentlichung der Ergebnisse erfolgt in einem Abschlussbericht und als DIN-Spezifikation (DIN SPEC). Diese DIN SPEC versetzt Prüfinstitute und Industrie in die Lage, Explosionsgefahren beim Betrieb technischer Anlagen mit hybriden Gemischen einzuschätzen und damit Prozesse sowohl sicherer als auch effizienter zu steuern. Dieses Projekt wird im Rahmen des WIPANOProgramms (Wissens- und Technologietransfer durch Patente und Normen) vom BMWi gefördert. T2 - 14. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit CY - Köthen, Germany DA - 07.11.2019 KW - Explosionsschutz KW - Sicherheitstechnische Kenngrößen KW - Hybride Gemische KW - Normung PY - 2019 SN - 978-3-89746-220-5 SP - 73 CY - Frankfurt am Main AN - OPUS4-49954 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, H. A1 - Braeuning, C. A1 - Kunz, B. M. A1 - Daher, H. A1 - Kästner, C. A1 - Krause, B.-C. A1 - Meyer, T. A1 - Jalili, P. A1 - Kogeveen, K. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Burel, A. A1 - Chevance, S. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Laux, P. A1 - Braeuning, A. A1 - Gauffre, F. A1 - Fessard, V. A1 - Meijer, J. A1 - Estrela-Lopis, I. A1 - Thünemann, Andreas A1 - Luch, A. A1 - Lampen, A. T1 - Uptake and molecular impact of aluminum-containing nanomaterials on human intestinal caco-2 cells N2 - Aluminum (Al) is one of the most common elements in the earth crust and increasingly used in food, consumer products and packaging. Its hazard potential for humans is still not completely understood. Besides the metallic form, Al also exists as mineral, including the insoluble oxide, and in soluble ionic forms. Representatives of these three species, namely a metallic and an oxidic species of Al-containing nanoparticles and soluble aluminum chloride, were applied to human intestinal cell lines as models for the intestinal barrier. We characterized physicochemical particle parameters, protein corona composition, ion release and cellular uptake. Different in vitro assays were performed to determine potential effects and molecular modes of Action related to the individual chemical species. For a deeper insight into signaling processes, microarray transcriptome analyses followed by bioinformatic data analysis were employed. The particulate Al species showed different solubility in biological media. Metallic Al nanoparticles released more ions than Al2O3 nanoparticles, while AlCl3 showed a mixture of dissolved and agglomerated particulate entities in biological media. The protein corona composition differed between both nanoparticle species. Cellular uptake, investigated in transwell experiments, occurred predominantly in particulate form, whereas ionic Al was not taken up by intestinal cell lines. Transcellular transport was not observed. None of the Al species showed cytotoxic effects up to 200 mg Al/mL. The transcriptome analysis indicated mainly effects on oxidative stress pathways, xenobiotic metabolism and metal homeostasis. We have shown for the first time that intestinal cellular uptake of Al occurs preferably in the particle form, while toxicological effects appear to be ion-related. KW - Small-angle x-ray scattering KW - SAXS KW - Nanopatricle PY - 2018 DO - https://doi.org/10.1080/17435390.2018.1504999 SN - 1743-5390 VL - 12 IS - 9 SP - 992 EP - 1013 PB - Taylor & Francis AN - OPUS4-47432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -