TY - JOUR A1 - Völker, Tobias A1 - Gornushkin, Igor B. T1 - Mass and mole fractions in calibration-free LIBS N2 - This technical note highlights the fact that CF-LIBS algorithms work in mole fractions, while results of spectrochemical analysis are usually reported in mass fractions or mass percent. Ignoring this difference and not converting mole fractions to mass fractions can lead to errors in reported concentrations determined by the CF-LIBS method and inadequate comparison of these concentrations with certified concentrations. Here, the key points of the CF-LIBS algorithm are reproduced and the formulae for converting a mole fraction to a mass fraction and vice versa are given. Several numerical examples are also given, which show that the greater the difference between the molar mass of an individual element in a sample and the average molar mass, the greater the discrepancy between the mole and mass fractions. KW - Spectroscopy KW - Analytical Chemistry KW - LIBS KW - Calibration PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598611 DO - https://doi.org/10.1039/d4ja00028e SN - 0267-9477 VL - 39 IS - 4 SP - 1030 EP - 1032 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Slotyuk, Lyubov A1 - Part, Florian A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris T1 - Life Cycle Assessment of the Domestic Micro Heat and Power Generation Proton Exchange Membrane Fuel Cell in Comparison with the Gas Condensing Boiler Plus Electricity from the Grid N2 - The energy demand of private households contributes globally to 36.5% of the total CO2 emissions. To analyze the emissions reduction potential, we conducted a comparative life cycle assessment of a proton exchange membrane fuel cell in a residential application and a conventional system with a stand-alone gas condensing boiler and electricity from a grid mix. The period under review was referred to as the service life of the PEMFC and is assumed to be 10 years (83,038 h of PEMFC). The applicability of this in a single-family house built between 1991 and 2000 under German climatic conditions was investigated. The functional unit is set to the thermal energy demand of 16,244 kWh/a and electricity demand of 4919 kWh/a of a single-family house. The impact assessment method “CML 2001–August 2016” was used in this investigation. The manufacturing phase of the proton exchange membrane fuel cell showed disadvantages, whereby the use phase had significant advantages in most of the environmental impact categories as compared to the conventional energy supply system. Considering the whole life cycle, the advantages from the use phase could outperform the disadvantages from the manufacturing phase in most of the impact categories, except for ADP elements and TETP. KW - Sustainability KW - Circular Economy KW - Comparative life cycle assessment KW - Proton exchange membrane fuel cell KW - Gas condensing boiler KW - Micro heat and power generation KW - Residential application KW - Single-family house energy supply system PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598134 DO - https://doi.org/10.3390/su16062348 VL - 16 IS - 6 SP - 1 EP - 16 PB - MDPI AG AN - OPUS4-59813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wetzel, Annica A1 - Morell, Daniel A1 - von der Au, Marcus A1 - Wittstock, Gunther A1 - Ozcan, Ozlem A1 - Witt, Julia T1 - Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis T1 - Transpassive Metallauflösung vs. Sauerstoffentwicklung: Auswirkungen auf Legierungsstabilität und Elektrokatalyse N2 - Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV-Vis) spectroscopy to elucidate metal dissolution processes. In-situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors. N2 - Multi-Hauptelement-Legierungen (MPEAs) gewinnen in der Korrosions- und Elektrokatalyseforschung aufgrund ihrer elektrochemischen Stabilität über einen breiten pH-Bereich und der Vielfalt der möglichen chemischen Zusammensetzungen zunehmend an Interesse. In unseren Untersuchungen mit der äquimolaren CrCoNi-Legierung in einem sauren Elektrolyten (0.1 M NaCl, pH 2) beobachteten wir eine signifikante Metallauflösung, die mit der Sauerstoffentwicklungsreaktion (OER) im transpassiven Bereich einhergeht, obwohl in zyklischen Polarisationskurven keine Hysterese auftrat oder andere offensichtliche Korrosionsindikatoren vorlagen. In diesem Artikel wird ein Charakterisierungskonzept eingeführt, dass die Beiträge der OER und der Legierungsauflösung differenziert. Hierfür kommt die elektrochemische Rastermikroskopie (SECM) zum Nachweis des Beginns der OER und die quantitative chemische Analyse mit induktiv gekoppelter Massenspektrometrie (ICP-MS) und UV/Vis-Spektrometrie zur Aufklärung der Metallauflösungsprozesse zum Einsatz. Die elektrochemische In situ-Atomkraftmikroskopie (EC-AFM) zeigte, dass die intergranulare Korrosion der dominierende Mechanismus der transpassive Metallauflösung von CrCoNi ist. Diese Ergebnisse besitzen erhebliche Auswirkungen für die Beurteilung der Stabilität von MPEAs in Korrosionssystemen und der Stromausbeute von OER-Katalysatoren auf der Basis von MPEAs. Die Daten unterstreichen die Notwendigkeit der analytischen Bestimmung von Metallionen, die von MPEA-Elektroden freigesetzt werden. Die Freisetzung von Übergangsmetallionen verringert nicht nur die Stromausbeute von Elektrolyseuren, sondern kann zu einer Schädigung von Membranen in elektrochemischen Reaktoren führen. KW - Transpassive dissolution KW - Corrosion KW - Multi-prinicpal element alloys (MPEAs) KW - Passivation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597045 DO - https://doi.org/10.1002/anie.202317058 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-59704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoogendoorn, Levi A1 - Huertas, Mauricio A1 - Nitz, Phillip A1 - Qi, Naiyu A1 - Baller, Johannes A1 - Prinz, Carsten A1 - Graeber, Gustav T1 - Sustainable, Low‐Cost Sorbents Based on Calcium Chloride‐Loaded Polyacrylamide Hydrogels N2 - AbstractSorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high‐performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high‐performance, cost‐efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel‐salt composites are shown to be stable under repeated sorption‐desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost‐performance ratio substantially exceeds lithium chloride‐based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low‐cost sorbent materials for future applications in water and energy. KW - Electrochemistry KW - Condensed Matter Physics KW - Biomaterials KW - Electronic, Optical and Magnetic Materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598366 DO - https://doi.org/10.1002/adfm.202314680 SN - 1616-301X SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-59836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Nils A1 - Dayani, Shahabeddin A1 - Markötter, Henning A1 - Bau, Alexander A1 - Setzchen, Max A1 - Schmidt, Anita A1 - Kowal, Julia A1 - Krug von Nidda, Jonas T1 - High Precision Nail‐Penetration Setup for the Controlled Thermal Runaway Initiation of Lithium‐Ion Cells at Very Low Temperatures N2 - A high precision nail‐penetration (NP) tool for characterizing the mechanically induced thermal‐runaway (TR) of lithium‐ion battery (LIB) cells in a defined range of temperatures down to −140 °C was developed. To understand the cell specific behavior at low temperatures aiming at the determination of safe handling conditions, different scenarios are analyzed. First, accuracy tests of the NP‐tool regarding motion and penetration depth are conducted with cylindrical cells at different temperatures. Thus, postmortem computer tomographic (CT) images are compared to the data measured with the newly integrated 3‐axis force sensor which is further combined with a high‐resolution position sensor. The herein developed setup allows evaluation of the NP‐metrics at an accuracy of ±1 pierced electrode layer without CT‐scans. Further NP examinations at 20 °C of fully charged cylindrical lithium nickel manganese cobalt oxide cells reveal a reproducible minimum damage as a reliable TR‐trigger. Moreover, NP‐tests at low temperature disclose a relation of the short circuit conductivity and TR‐reactions during subsequent rethermalization to room temperature. Finally, the implementation of a novel fixture for a controlled very fast cooling of LIB‐cells during critical damage opens the way to investigate the individual steps during a TR and, thus, to gain important information of the specific TR‐mechanism of different LIB‐cells. KW - Battery Safety KW - High-precision nail penetration KW - Lithium-ion batteries KW - Abuse testing KW - Thermal runaway PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598127 DO - https://doi.org/10.1002/ente.202301379 SN - 2194-4288 SP - 1 EP - 13 PB - Wiley VHC-Verlag AN - OPUS4-59812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Turski Silva Diniz, Analice A1 - Schartel, Bernhard T1 - The effects of property variation on the dripping behaviour of polymers during UL94 test simulated by particle finite element method N2 - The dripping behaviour of polymers is often observed experimentally through the UL94 flammability standard test. In this work, polymeric dripping under fire is investigated numerically using particle finite element method. A parametric analysis was carried out to observe the influence of a single property on overall dripping behaviour via a UL94 vertical test model. Surrogates and property ranges were defined for variation of the following parameters: glass transition temperature (Tg), melting temperature (Tm), decomposition temperature (Td), density (ρ), specific heat capacity (Cp), apparent effective heat of combustion of the volatiles, char yield (μ), thermal conductivity (k), and viscosity (η). Polyamide, poly(ether ether ketone), poly(methyl methacrylate), and polysulfone were used as benchmarks. Simulated results showed that specific heat capacity, thermal conductivity, and char yield allied with viscosity were the properties that most influenced dripping behaviour (starting time and occurrence). KW - Dripping KW - PFEM KW - UL 94 KW - Simulation KW - Fire behaviour PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597449 DO - https://doi.org/10.1515/epoly-2023-0194 SN - 1618-7229 VL - 24 IS - 1 PB - De Gruyter AN - OPUS4-59744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Groschke, Matthias A1 - Becker, Roland T1 - Comparison of carrier gases for the separation and quantification of mineral oil hydrocarbon (MOH) fractions using online coupled high performance liquid chromatography-gas chromatography-flame ionisation detection N2 - On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak. KW - Mineral oil hydrocarobons KW - Food KW - Liquid chromatography KW - Gas chromatography KW - MOSH/MOAH PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601450 DO - https://doi.org/10.1016/j.chroma.2024.464946 SN - 0021-9673 VL - 1726 SP - 1 EP - 7 PB - Elsevier CY - New York, NY AN - OPUS4-60145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López-Iglesias, C. A1 - Markovina, A. A1 - Nirmalananthan-Budau, N. A1 - Resch-Genger, Ute A1 - Klinger, D. T1 - Optically monitoring the microenvironment of a hydrophobic cargo in amphiphilic nanogels: influence of network composition on loading and release N2 - Amphiphilic nanogels (ANGs) are promising carriers for hydrophobic cargos such as drugs, dyes, and catalysts. Loading content and release kinetics of these compounds are controlled by type and number of hydrophobic groups in the amphiphilic copolymer network. Thus, understanding the interactions between cargo and colloidal carrier is mandatory for a tailor-made and cargo-specific ANG design. To systematically explore the influence of the network composition on these interactions, we prepared a set of ANGs of different amphiphilicity and loaded these ANGs with varying concentrations of the solvatochromic dye Nile Red (NR). Here, NR acts as a hydrophobic model cargo to optically probe the polarity of its microenvironment. Analysis of the NR emission spectra as well as measurements of the fluorescence quantum yields and decay kinetics revealed a decrease in the polarity of the NR microenvironment with increasing hydrophobicity of the hydrophobic groups in the ANG network and dye–dye interactions at higher loading concentrations. At low NR concentrations, the hydrophobic cargo NR is encapsulated in the hydrophobic domains. Increasing NR concentrations resulted in probe molecules located in a more hydrophilic environment, i.e., at the nanodomain border, and favored dye–dye interactions and NR aggregation. These results correlate well with release experiments, indicating first NR release from more hydrophilic network locations. Overall, our findings demonstrate the importance to understand carrier–drug interactions for efficient loading and controlled release profiles in amphiphilic nanogels. KW - Particle KW - Energy transfer KW - Limit of detection KW - Polymer KW - Luminescence KW - Quantitative spectroscopy KW - Nano KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Dye KW - Probe KW - Sensor KW - Nile Red PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601603 DO - https://doi.org/10.1039/d4nr00051j SN - 2040-3364 IS - 16 SP - 9525 EP - 9535 PB - The Royal Society of Chemistry AN - OPUS4-60160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Lisec, Jan A1 - Koch, Matthias T1 - Changes in Black Truffle (Tuber melanosporum) Aroma during Storage under Different Conditions N2 - The enticing aroma of truffles is a key factor for their culinary value. Although all truffle species tend to be pricy, the most intensely aromatic species are the most sought after. Research into the aroma of truffles encompasses various disciplines including chemistry, biology, and sensory science. This study focusses on the chemical composition of the aroma of black truffles (Tuber melanosporum) and the changes occurring under different storage conditions. For this, truffle samples were stored under different treatments, at different temperatures, and measured over a total storage time of 12 days. Measurements of the truffle aroma profiles were taken with SPME/GC–MS at regular intervals. To handle the ample data collected, a systematic approach utilizing multivariate data analysis techniques was taken. This approach led to a vast amount of data which we made publicly available for future exploration. Results reveal the complexity of aroma changes, with 695 compounds identified, highlighting the need for a comprehensive understanding. Principal component analyses offer initial insights into truffle composition, while individual compounds may serve as markers for age (formic acid, 1-methylpropyl ester), freshness (2-Methyl-1-propanal; 1-(methylthio)-propane), freezing (tetrahydrofuran), salt treatment (1-chloropentane), or heat exposure (4-hydroxy-3-methyl-2-butanone). This research suggests that heat treatment or salt contact significantly affects truffle aroma, while freezing and cutting have less pronounced effects in comparison. The enrichment of compounds showing significant changes during storage was investigated with a metabolomic pathway analysis. The involvement of some of the enriched compounds on the pyruvate/glycolysis and sulfur pathways was shown. KW - Mass Spectrometry KW - Metabolomics KW - Tuber melanosporum KW - Truffle Aroma PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601731 DO - https://doi.org/10.3390/jof10050354 VL - 10 IS - 5 SP - 1 EP - 22 PB - MDPI AN - OPUS4-60173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bauer, L.J. A1 - Wieder, Frank A1 - Truong, V. A1 - Förste, F. A1 - Wagener, Y. A1 - Jonas, A. A1 - Praetz, S: A1 - Schlesiger, C. A1 - Kupsch, Andreas A1 - Müller, B.R. A1 - Kanngießer, B. A1 - Zaslansky, P. A1 - Mantouvalou, I. T1 - Absorption Correction for 3D Elemental Distributions of Dental Composite Materials Using Laboratory Confocal Micro-X-ray Fluorescence Spectroscopy N2 - Confocal micro-X-ray fluorescence (micro-XRF) spectroscopy facilitates three-dimensional (3D) elemental imaging of heterogeneous samples in the micrometer range. Laboratory setups using X-ray tube excitation render the method accessible for diverse research fields but interpretation of results and quantification remain challenging. The attenuation of X-rays in composites depends on the photon energy as well as on the composition and density of the material. For confocal micro-XRF, attenuation severely impacts elemental distribution information, as the signal from deeper layers is distorted by superficial layers. Absorption correction and quantification of fluorescence measurements in heterogeneous composite samples have so far not been reported. Here, an absorption correction approach for confocal micro-XRF combining density information from microcomputed tomography (micro-CT) data with laboratory X-ray absorption spectroscopy (XAS) and synchrotron transmission measurements is presented. The energy dependency of the probing volume is considered during the correction. The methodology is demonstrated on a model composite sample consisting of a bovine tooth with a clinically used restoration material. KW - Micro X-ray fluorescence spectroscopy KW - Dental composite materials KW - Computed tomography KW - Absorption correction PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601630 DO - https://doi.org/10.1021/acs.analchem.4c00116 SN - 0003-2700 SN - 1520-6882 VL - 96 IS - 21 SP - 8441 EP - 8449 PB - American Chemical Society Publications CY - Washington, DC AN - OPUS4-60163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Marschall, Niklas A1 - Meinel, Dietmar A1 - Böhning, Martin T1 - Relation of craze to crack length during slow crack growth phenomena in high‐density polyethylene N2 - The craze‐crack mechanism occurring in high‐density polyethylene (HDPE) causing slow crack growth and environmental stress cracking is investigated in detail with respect to the relation of crack length and the related craze zone. This is essential for the understanding of the resulting features of the formed fracture surface and their interpretation in the context of the transition from crack propagation to ductile shear deformation. It turns out that an already formed craze zone does not inevitably result in formation of a propagating crack, but could also undergo ductile failure. For the examination, the full notch creep test (FNCT) was employed with a subsequent advanced fracture surface analysis that was performed using various imaging techniques: light microscopy, laser scanning microscopy, scanning electron microscopy, and X‐ray micro computed tomography scan. FNCT specimens were progressively damaged for increasing durations under standard test conditions applying Arkopal, the standard surfactant solution, and biodiesel as test media were used to analyze the stepwise growth of cracks and crazes. From considerations based on well‐established fracture mechanics approaches, a theoretical correlation between the length of the actual crack and the length of the preceding craze zone was established that could be evidenced and affirmed by FNCT fracture surface analysis. Moreover, the yield strength of a HDPE material exposed to a certain medium as detected by a classic tensile test was found to be the crucial value of true stress to induce the transition from crack propagation due to the craze‐crack mechanism to shear deformation during FNCT measurements. Highlights - Progress of crack formation in high‐density polyethylene is analyzed by different imaging techniques - Determined growth rates depend on distinction between craze zone and crack - The ratio of the present crack to the anteceding craze zone is validated theoretically - The transition from crack propagation to ductile shear deformation is identified - An already formed craze zone may still fail by ductile mechanisms KW - Craze-crack mechanism KW - Environmental stress cracking (ESC) KW - Full notch creep test (FNCT) KW - Laser scanning microscopy (LSM) KW - Slow crack growth (SCG) KW - X-ray computed tomography (CT) PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601831 DO - https://doi.org/10.1002/pen.26698 SN - 1548-2634 VL - 64 IS - 6 SP - 2387 EP - 2403 PB - Wiley AN - OPUS4-60183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ji, Y. A1 - Becker, S. A1 - Lu, Z. A1 - Mezhov, Alexander A1 - von Klitzing, R. A1 - Schmidt, Wolfram A1 - Stephan, D. T1 - Effect of resting time on rheological properties of glass bead suspensions - Depletion and bridging force among particles N2 - The effect of resting time on the rheological properties of cement suspensions is generally explained by early formed structure and overconsumption of polycarboxylate superplasticizers (PCEs). In this paper, we propose that the influence of resting time on the rheological properties is closely related to size variation of non-absorbed PCE. To identify this, glass bead suspensions were prepared with various amounts of PCE and ionic solution, and their rheological properties were evaluated at various times. We found that the yield stress increases with time at higher PCE concentrations and higher ionic strength solutions. Adsorbed PCE during resting tends to bridge the particles rather than disperse them. In addition, it was found that hydrodynamic radius of PCE increased with resting time, and depletion forces resulting from non-absorbed PCE size changes correlate well with the increased yield stress. KW - Depletion force KW - Ionic stregth KW - PCE KW - Rheology KW - Resting time PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587193 DO - https://doi.org/10.1111/jace.19469 SN - 0002-7820 SN - 1551-2916 VL - 107 IS - 1 SP - 624 EP - 639 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-58719 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nawaz, Q. A1 - Blaeß, Carsten A1 - Mueller, Ralf A1 - Boccaccini, A.R. T1 - Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses N2 - Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches. KW - Bioactive glass KW - Crystallization KW - Solubility KW - Cytocompatibility KW - Surface roughness PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598257 DO - https://doi.org/10.1016/j.oceram.2024.100586 SN - 2666-5395 VL - 18 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-59825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Tina A1 - Stark, T. A1 - Arduini, M. A1 - Manara, J. A1 - Altenburg, Simon T1 - Knowing the spectral directional emissivity of 316L and AlSi10Mg PBF-LB/M surfaces: Gamechanger for quantitative in situ monitoring N2 - For a deep process understanding of the laser powder bed fusion process (PBF-LB/M), recording of the occurring surface temperatures is of utmost interest and would help to pave the way for reliable process monitoring and quality assurance. A notable number of approaches for in-process monitoring of the PBF-LB/M process focus on the monitoring of thermal process signatures. However, due to the elaborate calibration effort and the lack of knowledge about the occurring spectral directional emissivity, only a few approaches attempt to measure real temperatures. In this study, to gain initial insights into occurring in the PBF-LB/M process, measurements on PBF-LB/M specimens and metal powder specimens were performed for higher temperatures up to T = 1290 °C by means of the emissivity measurement apparatus (EMMA) of the Center for Applied Energy Research (CAE, Wuerzburg, Germany). Also, measurements at ambient temperatures were performed with a suitable measurement setup. Two different materials—stainless steel 316L and aluminum AlSi10Mg—were examined. The investigated wavelength λ ranges from the visible range (λ-VIS= 0.40–0.75 µm) up to the infrared, λ = 20 µm. The influence of the following factors were investigated: azimuth angle φ, specimen temperature TS, surface texture as for PBF-LB/M surfaces with different scan angles α, and powder surfaces with different layer thicknesses t. T2 - Rapid.Tech 3D 2024 CY - Erfurt, Germany DA - 14.05.2024 KW - PBF-LB/M KW - In situ monitoring KW - Emissivity KW - Additive manufacturing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601471 DO - https://doi.org/10.1007/s40964-024-00665-2 SN - 2363-9520 SP - 1 EP - 10 PB - Springer CY - Cham, Switzerland AN - OPUS4-60147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kingsbery, P. A1 - Manzoni, Anna M. A1 - Suarez Ocaño, Patricia A1 - Többens, D. M. A1 - Stephan‐Scherb, C. T1 - High‐temperature KCl‐induced corrosion of high Cr and Ni alloys investigated by in‐situ diffraction N2 - High‐temperature KCl‐induced corrosion in laboratory air was observed in situ utilizing X‐ray diffraction. High Cr‐containing model alloys (Fe‐13Cr, Fe‐18Cr‐12Ni, and Fe‐25Cr‐20Ni) were coated with KCl and exposed to dry air at 560°C. KCl‐free alloys were studied in the equivalent atmosphere as a reference. After exposure to KCl‐free environments, all alloys showed the formation of very thin oxide layers, indicating good corrosion resistance. In contrast, KCl‐bearing alloys showed distinct damage after exposure. KW - Corrosion KW - In-situ diffraction KW - High-temperature corrosion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600831 DO - https://doi.org/10.1002/maco.202314224 SN - 0947-5117 SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-60083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hupp, Vitus A1 - Schartel, Bernhard A1 - Flothmeier, K. A1 - Hartwig, A. T1 - Fire Behavior of Pressure-sensitive Adhesive Tapes and Bonded Materials N2 - Pressure-sensitive adhesive tapes are used in several industrial applications such as con-struction, railway vehicles and the automotive sector,where the burning behavior is ofcrucial importance. Flame retarded adhesivetapes are developed and provided, however,often without considering the interaction of adhesive tapes and the bonded materialsduring burning nor the contribution of the tapes to fire protection goal of the bondedcomponents in distinct fire tests. This publication delivers an empirical comprehensiveknowledge how adhesive tapes and their flame retardancy effect the burning behaviorof bonded materials. With a special focus on the interaction between the single compo-nents, one flame retarded tape and one tapewithout flame retardant are examined inscenarios of emerging and developing fires, along with their bonds with the commonmaterials wood, zinc-plated steel, mineral wool, polycarbonate, and polymethylmethacry-late. The flame retardant significantly improved the flame retardancy of the tape as afree-standing object and yielded a V-2 rating in UL 94 vertical test and raised the OxygenIndex by 5 vol.%. In bonds, or rather laminates, the investigations prove that the choiceof carrier and substrates are the factors with the greatest impact on the fire propertiesand can change the peak of heat release rate and the maximum average rate of heatemission up to 25%. This research yielded a good empirical overall understanding of thefire behavior of adhesive tapes and bonded materials. Thus, it serves as a guide for tapemanufacturers and applicants to develop tapes and bonds more substrate specific. KW - Adhesives KW - Cone calorimeter KW - Flame retardancy KW - Laminates KW - Phosphorus flame retardants KW - Pressure-sensitive adhesive KW - Tapes PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593207 DO - https://doi.org/10.1002/fam.3171 SN - 0308-0501 SN - 1099-1018 VL - 48 IS - 1 SP - 114 EP - 127 PB - Wiley CY - New York, NY AN - OPUS4-59320 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weller, Michael G. T1 - The mystery of homochirality on earth N2 - Homochirality is an obvious feature of life on Earth. On the other hand, extraterrestrial samples contain largely racemic compounds. The same is true for any common organic synthesis. Therefore, it has been a perplexing puzzle for decades how these racemates could have formed enantiomerically enriched fractions as a basis for the origin of homochiral life forms. Numerous hypotheses have been put forward as to how preferentially homochiral molecules could have formed and accumulated on Earth. In this article, it is shown that homochirality of the abiotic organic pool at the time of formation of the first self-replicating molecules is not necessary and not even probable. It is proposed to abandon the notion of a molecular ensemble and to focus on the level of individual molecules. Although the formation of the first self-replicating, most likely homochiral molecule, is a seemingly improbable event, on a closer look, it is almost inevitable that some homochiral molecules have formed simply on a statistical basis. In this case, the non-selective leap to homochirality would be one of the first steps in chemical evolution directly out of a racemic “ocean”. Moreover, most studies focus on the chirality of the primordial monomers with respect to an asymmetric carbon atom. However, any polymer with a minimal size that allows folding to a secondary structure would spontaneously lead to asymmetric higher structures (conformations). Most of the functions of these polymers would be influenced by this inherently asymmetric folding. Furthermore, a concept of physical compartmentalization based on rock nanopores in analogy to nanocavities of digital immunoassays is introduced to suggest that complex cell walls or membranes were also not required for the first steps of chemical evolution. To summarize, simple and universal mechanisms may have led to homochiral self-replicating systems in the context of chemical evolution. A homochiral monomer pool is deemed unnecessary and probably never existed on primordial Earth. N2 - Homochiralität ist ein offensichtliches Merkmal des Lebens auf der Erde. Andererseits enthalten extraterrestrische Proben überwiegend racemische Verbindungen. Dasselbe gilt für jede gängige organische Synthese. Daher war es jahrzehntelang ein Rätsel, wie diese Racemate enantiomeren-angereicherte Fraktionen als Grundlage für den Ursprung homochiraler Lebensformen bilden konnten. Zahlreiche Hypothesen wurden aufgestellt, wie sich bevorzugt homochirale Moleküle auf der Erde gebildet und angereichert haben könnten. In diesem Artikel wird gezeigt, dass Homochiralität des abiotischen organischen Pools zum Zeitpunkt der Bildung der ersten selbstreplizierenden Moleküle nicht notwendig und nicht einmal wahrscheinlich ist. Es wird vorgeschlagen, die Vorstellung eines molekularen Ensembles aufzugeben und sich auf die Ebene der einzelnen Moleküle zu konzentrieren. Obwohl die Bildung des ersten selbstreplizierenden, höchstwahrscheinlich homochiralen Moleküls ein scheinbar unwahrscheinliches Ereignis ist, ist es bei näherer Betrachtung fast unvermeidlich, dass sich einige homochirale Moleküle einfach auf statistischer Basis gebildet haben. In diesem Fall wäre der nichtselektive Sprung zur Homochiralität einer der ersten Schritte der chemischen Evolution direkt aus einem racemischen "Ozean". Darüber hinaus konzentrieren sich die meisten Studien auf die Chiralität der ursprünglichen Monomere in Bezug auf ein asymmetrisches Kohlenstoffatom. Jedes Polymer mit einer Mindestgröße, die eine Faltung zu einer Sekundärstruktur erlaubt, würde jedoch spontan zu asymmetrischen höheren Strukturen (Konformationen) führen. Die meisten Funktionen dieser Polymere würden durch diese inhärent asymmetrische Faltung beeinflusst. Darüber hinaus wird ein Konzept der physikalischen Kompartimentierung auf der Basis von Gesteinsnanoporen in Analogie zu den Nanokavitäten digitaler Immunoassays vorgestellt, das darauf hindeutet, dass auch für die ersten Schritte der chemischen Evolution keine komplexen Zellwände oder Membranen notwendig waren. Zusammenfassend lässt sich sagen, dass einfache und universelle Mechanismen zu homochiralen selbstreplizierenden Systemen im Rahmen der chemischen Evolution geführt haben könnten. Ein homochiraler Monomerpool wird als unnötig angesehen, welcher auf der Urerde wahrscheinlich nie existiert hat. KW - Chemical evolution KW - Enantiomeric excess ee KW - Chirality KW - Racemate KW - Folding chirality KW - Self-assembly KW - self-replication KW - Single molecule KW - Prebiotic chemistry KW - Protein folding KW - Peptide folding KW - Proteinoid KW - Conformation KW - Segregation KW - Compartmentalization KW - Digital immunoassay KW - Porous rock KW - Miller and Urey KW - Primordial soup KW - Murchison meteorite KW - Micrometeorites KW - Tholins PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598349 DO - https://doi.org/10.3390/life14030341 SN - 2075-1729 VL - 14 IS - 3 SP - 1 EP - 13 PB - MDPI CY - Basel AN - OPUS4-59834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, Chi-Long A1 - Seeger, Stefan T1 - Measurement of sub-4 nm particle emission from FFF-3D printing with the TSI Nano Enhancer and the Airmodus Particle Size Magnifier N2 - The emission of ultrafine particles from small desktop Fused Filament Fabrication (FFF) 3D printers has been frequently investigated in the past years. However, the vast majority of FFF emission and exposure studies have not considered the possible occurrence of particles below the typical detection limit of Condensation Particle Counters and could have systematically underestimated the total particle emission as well as the related exposure risks. Therefore, we comparatively measured particle number concentrations and size distributions of sub-4 nm particles with two commercially available diethylene glycol-based instruments – the TSI 3757 Nano Enhancer and the Airmodus A10 Particle Size Magnifier. Both instruments were evaluated for their suitability of measuring FFF-3D printing emissions in the sub-4 nm size range while operated as a particle counter or as a particle size spectrometer. For particle counting, both instruments match best when the Airmodus system was adjusted to a cut-off of 1.5 nm. For size spectroscopy, both instruments show limitations due to either the fast dynamics or rather low levels of particle emissions from FFF-3D printing in this range. The effects are discussed in detail in this article. The findings could be used to implement sub-4 nm particle measurement in future emission or exposure studies, but also for the development of standard test protocols for FFF-3D printing emissions. KW - Air pollution KW - Ultrafine particles KW - Sub-4nm particles KW - FFF-3D printing KW - Emission testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595952 DO - https://doi.org/10.1080/02786826.2024.2320430 SN - 0278-6826 VL - 58 IS - 6 SP - 644 EP - 656 PB - Taylor & Francis CY - London AN - OPUS4-59595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Piechnik, Kira A1 - Hofmann, Anja A1 - Klippel, Andrea T1 - Self‐ignition of forest soil samples demonstrated through hot storage tests N2 - AbstractThe increasing threat of forest fires on a global scale is not only a matter of concern due to the potential harm they may cause to both human and animal life but also due to their significant role in exacerbating climate change. In light of these circumstances, one might inquire as to whether forest soil can self‐ignite and, if so, under what conditions and at what temperatures this phenomenon may occur. This question is being addressed in the German pilot “Fire science of wildfires and safety measures” of the EU project TREEADS, and the first results are presented below. The importance of basic research into the self‐ignition of forest soil cannot be underestimated, as it provides crucial knowledge to prevent forest fires and protect human and animal health. Furthermore, mitigating the occurrence of forest fires can also play a role in reducing greenhouse gas emissions, contributing to global efforts to combat climate change. The procedure of the hot storage test is an effective means of determining whether a material can self‐ignite. During the investigation of six soil samples, it was found that five of them were indeed capable of self‐ignition. In addition to determining whether the material ignites, the modified hot storage test also analyzed the resulting smoke gases and measured their concentration. The research question of whether regional forest soil is capable of self‐ignition can be answered with yes based on these initial tests. Further experiments are needed to determine if self‐ignition causes forest fires. KW - FTIR KW - Hot storage KW - Ignition KW - Soil KW - Wildfire PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594617 DO - https://doi.org/10.1002/fam.3198 VL - 48 IS - 4 SP - 495 EP - 507 PB - Wiley AN - OPUS4-59461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Stephan A1 - Hoffmann, Holger A1 - Garbe, Leif-Alexander A1 - Harrer, Andrea A1 - Steiner, Markus A1 - Himly, Martin A1 - Schneider, Rudolf T1 - Re-assessment of monoclonal antibodies against diclofenac for their application in the analysis of environmental waters N2 - The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is an important environmental contaminant occurring in surface waters all over the world, because, after excretion, it is not adequately removed from wastewater in sewage treatment plants. To be able to monitor this pollutant, highly efficient analytical methods are needed, including immunoassays. In a medical research project, monoclonal antibodies against diclofenac and its metabolites had been produced. Based on this monoclonal anti-DCF antibody, a new indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed and applied for environmental samples. The introduction of a spacer between diclofenac and the carrier protein in the coating conjugate led to higher sensitivity. With a test midpoint of 3 mg L−1 and a measurement range of 1–30 mg L−1, the system is not sensitive enough for direct analysis of surface water. However, this assay is quite robust against matrix influences and can be used for wastewater. Without adjustment of the calibration, organic solvents up to 5%, natural organic matter (NOM) up to 10 mg L−1, humic acids up to 2.5 mg L−1, and salt concentrations up to 6 g L−1 NaCl and 75 mg L−1 CaCl2 are tolerated. The antibody is also stable in a pH range from 3 to 12. Cross-reactivity (CR) of 1% or less was determined for the metabolites 40-hydroxydiclofenac (40-OH-DCF), 5-hydroxydiclofenac (5-OH-DCF), DCF lactam, and other NSAIDs. Relevant cross-reactivity occurred only with an amide derivative of DCF, 6-aminohexanoic acid (DCF-Ahx), aceclofenac (ACF) and DCF methyl ester (DCF-Me) with 150%, 61% and 44%, respectively. These substances, however, have not been found in samples. Only DCF-acyl glucuronide with a cross-reactivity of 57% is of some relevance. For the first time, photodegradation products were tested for cross-reactivity. With the ELISA based on this antibody, water samples were analysed. In sewage treatment plant effluents, concentrations in the range of 1.9–5.2 mg L−1 were determined directly, with recoveries compared to HPLC-MS/MS averaging 136%. Concentrations in lakes ranged from 3 to 4.4 ng L−1 and were, after pre-concentration, determined with an average recovery of 100% KW - Antikörper KW - Immunoassay KW - Wasser PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602280 DO - https://doi.org/10.1039/d3ay01333b VL - 16 IS - 21 SP - 3349 EP - 3363 PB - Royal Society of Chemistry (RSC) CY - London AN - OPUS4-60228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -