TY - JOUR A1 - Tschöke, K. A1 - Müller, I. A1 - Memmolo, V. A1 - Moix-Bonet, M. A1 - Moll, J. A1 - Lugovtsova, Yevgeniya A1 - Golub, M. A1 - Sridaran Venkat, R. A1 - Schubert, L. T1 - Feasibility of Model-Assisted Probability of Detection Principles for Structural Health Monitoring Systems based on Guided Waves for Fibre-Reinforced Composites N2 - In many industrial sectors, Structural Health Monitoring (SHM) is considered as an addition to Non-Destructive Testing (NDT) that can reduce maintenance effort during lifetime of a technical facility, structural component or vehicle. A large number of SHM methods is based on ultrasonic waves, whose properties change depending on structural health. However, the wide application of SHM systems is limited due to the lack of suitable methods to assess their reliability. The evaluation of the system performance usually refers to the determination of the Probability of Detection (POD) of a test procedure. Up to now, only few limited methods exist to evaluate the POD of SHM systems, which prevent them from being standardised and widely accepted in industry. The biggest hurdle concerning the POD calculation is the large amount of samples needed. A POD analysis requires data from numerous identical structures with integrated SHM systems. Each structure is then damaged at different locations and with various degrees of severity. All of this is connected to high costs. Therefore, one possible way to tackle this problem is to perform computer-aided investigations. In this work, the POD assessment procedure established in NDT according to the Berens model is adapted to guided wave-based SHM systems. The approach implemented here is based on solely computer-aided investigations. After efficient modelling of wave propagation phenomena across an automotive component made of a carbon fibre-reinforced composite, the POD curves are extracted. Finally, the novel concept of a POD map is introduced to look into the effect of damage position on system reliability. KW - Reliability KW - Acoustics KW - Monitoring KW - Automotive engineering KW - Elastodynamic Finite Inegration Technique PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528218 DO - https://doi.org/10.1109/TUFFC.2021.3084898 VL - 68 IS - 10 SP - 3156 EP - 3173 AN - OPUS4-52821 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Plichta, T. A1 - Sirjovona, V. A1 - Zvonek, M. A1 - Kalinka, Gerhard A1 - Cech, V. T1 - The Adhesion of Plasma Nanocoatings Controls the Shear Properties of GF/Polyester Composite N2 - High-performance fibre-reinforced polymer composites are important construction materials based not only on the specific properties of the reinforcing fibres and the flexible polymer Matrix but also on the compatible properties of the composite interphase. First, oxygen-free (a-CSi:H) and oxygen-binding (a-CSiO:H) plasma nanocoatings of different mechanical and tribological properties were deposited on planar silicon dioxide substrates that closely mimic E-glass. The nanoscratch test was used to characterize the nanocoating adhesion expressed in terms of critical normal load and work of adhesion. Next, the same nanocoatings were deposited on E-glass fibres, which were used as reinforcements in the polyester composite to affect its interphase properties. The shear properties of the polymer composite were characterized by macro- and micromechanical tests, namely a short beam shear test to determine the short-beam strength and a single fibre push-out test to determine the interfacial shear strength. The results of the polymer composites showed a strong correlation between the short-beam strength and the interfacial shear strength, proving that both tests are sensitive to changes in fibre-matrix adhesion due to different surface modifications of glass fibres (GF). Finally, a strong correlation between the shear properties of the GF/polyester composite and the adhesion of the plasma nanocoating expressed through the work of adhesion was demonstrated. Thus, increasing the work of adhesion of plasma nanocoatings from 0.8 to 1.5 mJ·m−2 increased the short-beam strength from 23.1 to 45.2 MPa. The results confirmed that the work of adhesion is a more suitable parameter in characterising the level of nanocoating adhesion in comparison with the critical normal load. KW - Mechanical properties KW - Plasma nanocoatings KW - Glass fibre KW - Polymer composite KW - Short-beam strength KW - Interfacial shear strength KW - Work of adhesion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521844 DO - https://doi.org/10.3390/polym13040593 VL - 13 IS - 4 SP - 593 PB - MDPI CY - Basel,Schweiz AN - OPUS4-52184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seeger, Stefan A1 - Osan, J. A1 - Czömpöly, O. A1 - Gross, A. A1 - Stosnach, H. A1 - Stabile, L. A1 - Ochsenkuehn-Petropoulou, M. A1 - Tsakanika, L. A1 - Lymperopoulou, T. A1 - Goddard, S. A1 - Fiebig, M. A1 - Gaie-Levrel, F. A1 - Kayser, Y. A1 - Beckhoff, B. T1 - Quantification of Element Mass Concentrations in Ambient Aerosols by Combination of Cascade Impactor Sampling and Mobile Total Reflection X-ray Fluorescence Spectroscopy N2 - Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing EU air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). During the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling is combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution only a few hours and with good size resolution in the PM10 range. The study investigates the proof of principles of this methodological approach. Acrylic discs and silicon wafers are shown to be suitable impactor carriers with sufficiently smooth and clean surfaces, and a non-destructive elemental mass concentration measurement with a lower limit of detection around 10 pg/m3 could be achieved. We demonstrate the traceability of field TXRF measurements to a radiometrically calibrated TXRF reference, and the results from both analytical methods correspond satisfactorily. KW - TXRF KW - Reference method KW - Cascade impactor KW - Ambient aerosols KW - Particles KW - Air quality monitoring KW - Element mass concentration KW - Size resolved chemical composition KW - Time resolved chemical composition KW - ICP-MS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521860 UR - http://www.aerometproject.com/ DO - https://doi.org/10.3390/atmos12030309 SN - 2073-4433 VL - 12 IS - 3 SP - 309 EP - 337 PB - MDPI CY - Basel, Schweiz AN - OPUS4-52186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Saied, M. A. A. A1 - Morgan, N. A1 - Abdelbary, H. A1 - Bahy, S. M. A1 - Schönhals, Andreas A1 - Friedrich, J. F. T1 - Modified polyvinyl chloride membrane grafted with an ultra-thin polystyrene film: structure and electrochemical properties N2 - The work explores the synthesis and the properties of a novel composite membrane System based on modified polystyrene (PS) grafted onto a polyvinyl chloride (PVC) membrane. PVC membranes were prepared by solution-casting followed by exposure to an atmospheric pressure dielectric barrier discharge (DBD) with O2 to obtain an activated Surface for grafting PS to it. Moreover, the thus prepared membranes were chemically modified furthermore by amination with polyethyleneimine or sulfonation with 4 M sulfuric acid. The membrane surface characteristics such as wettability, structure and morphology were investigated using water contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy experiments. The thermogravimetric stability and electrolytic responses of the membranes were studied utilizing TGA, ion exchange capacity (IEC), and solvent uptake. A significant result of plasma and chemical modification was to produce a membrane material with low permeability. Thus, the methanol permeability of the sulfonated membranes measured for 12 h was measured to 2.34$10� 8 cm2 s� 1 compared to 177.00$10� 8 cm2 s� 1 of Nafion 117®which is considered as a benchmark. This result indicates that the prepared sulfonated samples are an innovative and effective material for decreasing the methanol crossover in fuel cells to a great extent. This makes the PVC-g-St membranes are promising and attractive as new materials for polyelectrolyte membrane for fuel cells. KW - Electrolyte membrane KW - Fuell cells PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526794 DO - https://doi.org/10.1016/j.jmrt.2021.04.018 VL - 12 SP - 2273 EP - 2284 PB - Elsevier B.V. AN - OPUS4-52679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fürst, Richard A1 - Fürst, E. A1 - Vlach, T. A1 - Repka, J. A1 - Pokorny, M. A1 - Mozer, V. T1 - Use of Cement Suspension as an Alternative Matrix Material for Textile-Reinforced Concrete N2 - Textile-reinforced concrete (TRC) is a material consisting of high-performance concrete (HPC) and tensile reinforcement comprised of carbon roving with epoxy resin matrix. However, the problem of low epoxy resin resistance at higher temperatures persists. In this work, an alternative to the epoxy resin matrix, a non-combustible cement suspension (cement milk) which has proven stability at elevated temperatures, was evaluated. In the first part of the work, microscopic research was carried out to determine the distribution of particle sizes in the cement suspension. Subsequently, five series of plate samples differing in the type of cement and the method of textile reinforcement saturation were designed and prepared. Mechanical experiments (four-point bending tests) were carried out to verify the properties of each sample type. It was found that the highest efficiency of carbon roving saturation was achieved by using finer ground cement (CEM 52.5) and the pressure saturation method. Moreover, this solution also exhibited the best results in the four-point bending test. Finally, the use of CEM 52.5 in the cement matrix appears to be a feasible variant for TRC constructions that could overcome problems with its low temperature resistance. KW - Textile-reinforced concrete KW - High-performance concrete KW - Carbon fibers KW - Cement matrix PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527100 DO - https://doi.org/10.3390/ma14092127 SN - 1996-1944 VL - 14 IS - 9 SP - 2127 PB - MDPI CY - Basel AN - OPUS4-52710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlick-Hasper, Eva A1 - Bruchno, Martin A1 - Thomas, Goedecke T1 - Release of Powdery or Granular Substances from Intact Dangerous Goods Bags During Road Transport - Analysis of the Causes and Development of a Test Concept N2 - The leaks of dangerous goods from actually intact bags detected in the years 2018 to 2020 tend to be at an almost constant high level. These releases of powdery or granular dangerous goods represent violations of the sift-proofness required in the dangerous goods regulations. This article first analyzes the causes. The components of the bags that are affected by leaks are micro-perforations, joins and closures, in particular internal sleeve valves. A distinction must be made between bags closed in conformity with or contrary to the manufacturer's instructions. The particle release is determined by a number of influencing factors of the filling substance, the packaging and other boundary conditions. Therefore, a comprehensive test concept is developed in this work, which takes all these factors into account. The application of this test concept facilitates the planning of the test setup and the experiments. On this basis, the complex mechanisms involved in the release of solid substances can be systematically investigated in the test laboratory. To prevent releases of powdery or granular substances from intact bags, it is necessary that the user has access to the closing instructions and the relevant properties of the test substance used for the design type approval. Further experimental investigations are needed to assess whether filling substances change their properties during transport and whether this enables them to escape. KW - Bags KW - Dangerous goods packagings KW - Leak KW - Particles KW - Sift-proofness PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527287 DO - https://doi.org/10.1002/pts.2575 SN - 0894-3214 VL - 34 IS - 7 SP - 435 EP - 446 PB - Wiley AN - OPUS4-52728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ecke, Alexander A1 - Schneider, Rudolf T1 - Pitfalls in the Immunochemical Determination of β-Lactam Antibiotics in Water N2 - Contamination of waters with pharmaceuticals is an alarming problem as it may support the evolution of antimicrobial resistance. Therefore, fast and cost-effective analytical methods for potential on-site analysis are desired in order to control the water quality and assure the safety of its use as a source of drinking water. Antibody-based methods, such as the enzyme-linked immunosorbent assay (ELISA), can be helpful in this regard but can also have certain pitfalls in store, depending on the analyte. As shown here for the class of β-lactam antibiotics, hydrolysis of the β-lactam ring is a key factor in the immunochemical analysis as it influences antibody recognition. With the antibody used in this study, the limit of detection (LOD) in the immunoassay could be significantly reduced by hydrolysis for the five tested penicillins, with the lowest LOD for carbenicillin (0.2 nmol/L) and the greatest impact on penicillins G and V (reduction by 85%). In addition to enhanced quantification, our strategy also provides access to information about the degree of hydrolysis in water samples as shown for the most abundant penicillin amoxicillin. KW - ELISA KW - Immunoassay KW - β-Lactam KW - Amoxicillin KW - Hydrolysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522832 DO - https://doi.org/10.3390/antibiotics10030298 SN - 2079-6382 VL - 10 IS - 3 SP - 298 PB - MDPI CY - Basel, CH AN - OPUS4-52283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Denkler, Tilman T1 - Accreditation in Europe: Benchmarking the operations of European accreditation bodies using an innovative management tool N2 - Accreditation is one of the pillars of a national Quality Infrastructure, as the competence of conformity assessment bodies is assured through accreditation performed by accreditation bodies. To compare the operation of accreditation bodies in Europe and to identify best practices, a management tool, the Process Maturity Benchmarking Tool, was developed and validated by applying it to European accreditation bodies. The benchmarking project comprised two major phases: In the first phase, the processes of accreditation bodies were systematically analyzed. A process map was developed, and processes of special relevance were identified and underpinned by indicators. In the second phase, the practical applicability of the theoretical model was demonstrated by analyzing the processes of eight European accreditation bodies. The results of this comparative assessment were subsequently discussed in a workshop with experts from those accreditation bodies, giving the opportunity to identify best practices. This article has a twofold objective. First, to present a method to benchmark European accreditation bodies, based on the European Foundation for Quality Management excellence model. The successful application of the Process Maturity Benchmarking Tool gives evidence that it is a suitable and capable management tool to assess the processes of the European accreditation bodies and to benchmark them. Second, the article presents the results of the first adaption of the Process Maturity Benchmarking Tool. A general trend of process maturity was identified: While processes based on stakeholder involvement tend to have an overall lower maturity on average, internal processes are more mature. KW - Accreditation KW - Benchmarking KW - Quality Infrastructure KW - EFQM Excellence Modell KW - Total Quality Management KW - Akkreditierung PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521706 DO - https://doi.org/10.1007/s00769-021-01459-7 VL - 26 IS - 1 SP - 47 EP - 57 PB - Springer Nature CY - Jersey City, NJ 07302, USA AN - OPUS4-52170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Abbasi, M. A1 - Pauw, Brian Richard A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schick, C. A1 - Saalwächter, K. A1 - Schönhals, Andreas T1 - Spatial inhomogeneity, Interfaces and Complex Vitrification Kinetics in a Network Forming Nanocomposite N2 - A detailed calorimetric study on an epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) as the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) as nanofiller. The -NH2 group of taurine can react with DGEBA improving the interaction of the polymer with the filler. The combined X-ray scattering, and electron microscopy data showed that the nanocomposite has a partially exfoliated morphology. Calorimetric studies were performed with conventional DSC, temperature modulated DSC (TMDSC) and fast scanning calorimetry (FSC) in the temperature modulated approach (TMFSC) to investigate the vitrification and molecular mobility in dependence of the filler concentration. First, TMDSC and NMR were used to estimate the amount of the rigid amorphous fraction which consists of immobilized polymer segments at the nanoparticle surface. It was found to be 40 wt% for the highest filler concentration, indicating that the interface dominates the overall macroscopic properties and behavior of the material to a great extent. Second, the relaxation rates of the α-relaxation obtained by TMDSC and TMFSC were compared with the thermal and dielectric relaxation rates measured by static FSC. The investigation revealed that the system shows two distinct α-relaxation processes. Furthermore, also two separate vitrification mechanisms were found for a bulk network-former without geometrical confinement as also confirmed by NMR. This was discussed in terms of the intrinsic spatial heterogeneity on a molecular scale, which becomes more pronounced with increasing nanofiller content. KW - Polymer based Nanocomposites PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523199 DO - https://doi.org/10.1039/d0sm01992e SN - 1744-6848 VL - 17 IS - 10 SP - 2775 EP - 2790 PB - Royal Society of Chemistry AN - OPUS4-52319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Zutta Villate, J. M. ED - Zutta Villate, J. M. T1 - Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of Radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for future experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au. KW - AuNP KW - Beta decay KW - Brachytherapy KW - Cancer treatment KW - DNA KW - DNA damage KW - Dosimetry KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Gold Nanoparticles KW - LEE KW - MCS KW - Microdosimetry KW - Monte-Carlo simulation KW - NP KW - Ectoine KW - OH radicals KW - Radiation damage KW - Radiationtherapy KW - Radioactive decay KW - Simulation KW - Beta particle KW - Clustered nanoparticles KW - Gamma ray KW - Low energy electrons KW - Particle scattering KW - Radiolysis KW - Livermore model KW - Penelope model KW - TOPAS KW - TOPAS-nbio PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523276 DO - https://doi.org/10.1038/s41598-021-85964-2 SN - 2045-2322 VL - 11 IS - 1 SP - 6721 PB - Springer Nature AN - OPUS4-52327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -