TY - JOUR A1 - Alrwashdeh, S. S. A1 - Markötter, H. A1 - Haußmann, J. A1 - Hilger, A. A1 - Klages, M. A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Manke, I. T1 - Investigation of water transport in newly developed micro porous layers for polymer electrolyte membrane fuel cells N2 - In this investigation, synchrotron X-ray imaging was used to investigate the water distribution inside newly developed gas diffusion media in polymer electrolyte membrane fuel cells. In-situ radiography was used to reveal the relationship between the structure of the microporous layer (MPL) and the water flow in a newly developed MPL equipped with randomly arranged holes. A strong influence of these holes on the overall water transport was found. This contribution provides a brief overview to some of our recent activities on this research field. KW - Polymer electrolyte membrane fuel cell KW - Microporous layer KW - Water distribution KW - Radiography KW - Synchrotron X-ray imaging PY - 2017 DO - https://doi.org/10.9729/AM.2017.47.3.101 SN - 2287-4445 SN - 2287-5123 VL - 47 IS - 3 SP - 101 EP - 104 AN - OPUS4-43356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Denißen, M. A1 - Nirmalananthan-Budau, Nithiya A1 - Behnke, Thomas A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Müller, T. J. J. T1 - 3-Piperazinyl propenylidene indolone merocyanines: consecutive three-component synthesis and electronic properties of solid-state luminophores with AIE properties N2 - A series of twelve 3-piperazinyl propenylidene indolone merocyanines was synthesized in a one-pot fashion using a consecutive three-component insertion-coupling-Michael addition sequence. Physicalorganic treatment of the absorption data of a consanguineous series of this library allows semiquantitative Linear Free Energy Relationships (LFERs) to be established and confirmation of the positive Absorption solvatochromicity. All Boc-substituted piperazinyl merocyanines display aggregation induced Emission (AIE), which was corroborated for two solvent systems. In particular, crystallization-induced Emission enhancement (CIEE) induced by ultrasonication could be shown for a model chromophore by confocal laser scanning microscopy (CLSM). KW - Indolone merocyanines KW - AIE KW - CIEE KW - CLSM PY - 2017 DO - https://doi.org/10.1039/c7qm00198c SN - 2052-1537 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. VL - 1 IS - 10 SP - 2013 EP - 2026 AN - OPUS4-43213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Buckle, T. A1 - van der Wal, S. A1 - van Malderen, S. A1 - Müller, Larissa A1 - Kuil, J. A1 - van Unen, V. A1 - Peters, R. A1 - van Bemmel, M. A1 - McDonnell, L. A1 - Velders, A. A1 - Koning, F. A1 - Vanhaeke, F. A1 - van Leeuwen, F. T1 - Hybrid imaging labels: providing the link between mass spectrometry-based molecular pathology and theranostics N2 - Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for in vitro and in vivo evaluation; e.g. fluorescence or nuclear medicine. In this study a bimodal (or rather, hybrid) tracer that contains both a fluorescent dye and a chelate was used to evaluate the existence of a direct link between mass spectrometry (MS) and in vitro and in vivo molecular imaging findings using fluorescence and radioisotopes. At the same time, the hybrid label was used to determine whether the use of a single isotope label would allow for MS-based diagnostics. KW - Imaging KW - Laser Ablation ICP-MS KW - Diagnostics PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396813 DO - https://doi.org/10.7150/thno.17484 VL - 7 IS - 3 SP - 624 EP - 633 PB - IvySpring AN - OPUS4-39681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer, Klas A1 - Paul, Andrea A1 - Ruiken, J.-P. A1 - Westad, Frank A1 - Illner, M. A1 - Müller, D. A1 - Esche, E. A1 - Repke, J.-U. A1 - Maiwald, Michael T1 - Online Spectroscopy in Microemulsions – A Process Analytical Approach for a Hydroformylation Mini-plant N2 - Within the Collaborative Research Center InPROMPT a novel process concept for the hydroformylation of long-chained olefins is studied in a mini-plant, using a rhodium complex as catalyst in the presence of syngas. Recently, the hydroformylation in micro¬emulsions, which allows for the efficient recycling of the expensive rhodium catalyst, was found to be feasible. However, the high sensitivity of this multi-phase system with regard to changes in temperature and composition demands a continuous observation of the reaction to achieve a reliable and economic plant operation. For that purpose, we tested the potential of both online NMR and Raman spectroscopy for process control. The lab-scale experiments were supported by off-line GC-analysis as a reference method. A fiber optic coupled probe of a process Raman spectrometer was directly integrated into the reactor. 25 mixtures with varying concentrations of olefin (1-dodecene), product (n-tridecanal), water, n-dodecane, and technical surfactant (Marlipal 24/70) were prepared according to a D-optimal design. Online NMR spectroscopy was implemented by using a flow probe equipped with 1/16” PFA tubing serving as a flow cell. This was hyphenated to the reactor within a thermostated bypass to maintain process conditions in the transfer lines. Partial least squares regression (PLSR) models were established based on the initial spectra after activation of the reaction with syngas for the prediction of unknown concentrations of 1-dodecene and n-tridecanal over the course of the reaction in the lab-scale system. The obtained Raman spectra do not only contain information on the chemical composition but are further affected by the emulsion properties of the mixtures, which depend on the phase state and the type of micelles. Based on the spectral signature of both Raman and NMR spectra, it could be deduced that especially in reaction mixtures with high 1-dodecene content the formation of isomers as a competitive reaction was dominating. Similar trends were also observed during some of the process runs in the mini-plant. The multivariate calibration allowed for the estimation of reactants and products of the hydroformylation reaction in both laboratory setup and mini-plant. T2 - 4th European Conference on Process Analytics and Control Technology (EuroPACT 2017) CY - Potsdam, Germany DA - 10.05.2017 KW - Microemulsions KW - Process Analytical Technology KW - Reaction Monitoring KW - Online NMR Spectroscopy KW - Online Raman Spectroscopy PY - 2017 SP - 64 EP - 64 CY - Frankfurt a. M. AN - OPUS4-40228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, Klas A1 - Ruiken, J.-P. A1 - Illner, M. A1 - Paul, Andrea A1 - Müller, D. A1 - Esche, E. A1 - Wozny, G. A1 - Maiwald, Michael T1 - Process spectroscopy in microemulsions - setup and multi-spectral approach for reaction monitoring of a homogeneous hydroformylation process N2 - Reaction monitoring in disperse systems, such as emulsions, is of significant technical importance in various disciplines like biotechnological engineering, chemical industry, food science, and a growing number other technical fields. These systems pose several challenges when it comes to process analytics, such as heterogeneity of mixtures, changes in optical behavior, and low optical activity. Concerning this, online nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for process monitoring in complex reaction mixtures due to its unique direct comparison abilities, while at the same time being non-invasive and independent of optical properties of the sample. In this study the applicability of online-spectroscopic methods on the homogeneously catalyzed hydroformylation system of 1-dodecene to tridecanal is investigated, which is operated in a mini-plant scale at Technische Universität Berlin. The design of a laboratory setup for process-like calibration experiments is presented, including a 500 MHz online NMR spectrometer, a benchtop NMR device with 43 MHz proton frequency as well as two Raman probes and a flow cell assembly for an ultraviolet and visible light (UV/VIS) spectrometer. Results of high-resolution online NMR spectroscopy are shown and technical as well as process-specific problems observed during the measurements are discussed. KW - Online-spectroscopy KW - Quantitative NMR spectroscopy KW - Process analytical technology KW - Microemulsions PY - 2017 DO - https://doi.org/10.1088/1361-6501/aa54f3 SN - 0957-0233 SN - 1361-6501 VL - 28 IS - 3 SP - 035501-1 EP - 035501-11 PB - IOP Publishing Ltd. AN - OPUS4-39091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nellesen, J. A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Hentschel, M. P. A1 - Anar, N. B. A1 - Soppa, E. A1 - Tillmann, W. A1 - Bruno, Giovanni T1 - In situ analysis of damage evolution in an Al/Al2O3 MMC under tensile load by synchrotron X-ray refraction imaging N2 - The in situ analysis of the damage evolution in a metal Matrix composite (MMC) using synchrotron X-ray refraction radiography (SXRR) is presented. The investigated material is an Al alloy (6061)/10 vol% Al2O3 MMC after T6 heat treatment. In an interrupted tensile test the gauge section of dog bone-shaped specimens is imaged in different states of tensile loading. On the basis of the SXRR images, the relative change of the specific surface (proportional to the amount of damage) in the course of tensile loading was analyzed. It could be shown that the damage can be detected by SXRR already at a stage of tensile loading, in which no Observation of damage is possible with radiographic absorption-based imaging methods. Moreover, the quantitative analysis of the SXRR images reveals that the amount of damage increases homogeneously by an average of 25% with respect to the Initial state. To corroborate the experimental findings, the damage distribution was imaged in 3D after the final tensile loading by synchrotron X-ray refraction computed tomography (SXRCT) and absorption-based synchrotron X-ray computed tomography (SXCT). It could be evidenced that defects and damages cause pronounced indications in the SXRCT images. KW - Composite materials KW - Defects KW - Micro analysis PY - 2018 DO - https://doi.org/10.1007/s10853-017-1957-x SN - 0022-2461 SN - 1573-4803 VL - 53 IS - 8 SP - 6021 EP - 6032 PB - Springer US AN - OPUS4-44241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Behrens, H. A1 - Bauer, U. A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Müller, Ralf A1 - Deubener, J. T1 - Structural relaxation mechanisms in hydrous sodium borosilicate glasses N2 - Borosilicate glasses (16Na2O–10B2O3–74SiO2, NBS) with water contents up to 22 mol% H2O were prepared to study the effect of water on structural relaxation using DTA, viscometry and internal friction measurements. The results show that the glass transition temperature Tg of DTA and the isokom temperature T12, of viscometry are in excellent agreement, confirming the equivalence of enthalpy and viscous relaxation for NBS glass. Combining Tg data with water speciation data demonstrates that OH groups are mainly responsible for the decrease of Tg with increasing hydration, while molecular water plays only a minor role. Internal friction spectra at 7.125 Hz confirm the decisive influence of water on mechanical relaxation. The temperature range of α-relaxation (glass transition) strongly decreases while two β-relaxation peaks (sub-Tg) progressively appear with increasing water content. A high temperature β-relaxation peak, attributed to the presence of OH groups, shifts from 670 to 450 K as total water content increases from 0.01 to 5 wt%. A low temperature β-relaxation peak, attributed to molecular water, appears at 380 K and 330 K in glasses containing 3 and 5 wt% H2O, respectively. These findings suggest that relaxation mechanism of different hydrous species at low temperature may contribute to fatigue of stressed glasses. KW - Borosilicate glass KW - Water KW - Relaxation KW - Internal friction KW - Glass transition PY - 2018 DO - https://doi.org/10.1016/j.jnoncrysol.2018.05.025 VL - 497 SP - 30 EP - 39 PB - Elsevier B.V. AN - OPUS4-45608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nirmalananthan-Budau, Nithiya A1 - Behnke, Thomas A1 - Hoffmann, Katrin A1 - Kage, Daniel A1 - Gers-Panther, Charlotte F. A1 - Frank, Walter A1 - Müller, Thomas J. J. A1 - Resch-Genger, Ute T1 - Crystallization and Aggregation-Induced Emission in a Series of Pyrrolidinylvinylquinoxaline Derivatives N2 - Aggregation-induced emission (AIE) has been meanwhile observed for many dye classes and particularly for fluorophores containing propeller-like groups. Herein, we report on the AIE characteristics of a series of four hydrophobic pyrrolidinylvinylquinoxaline (PVQ) derivatives with phenyl, pyrrolyl, indolyl, and methoxythienyl substituents used to systematically vary the torsion angle between this substituent at the quinoxaline C2 position and the planar PVQ moiety. These molecules, which are accessible via four- or five-component one-pot syntheses, were spectroscopically studied in organic solvents and solvent−water mixtures, as dye aggregates, solids, and entrapped in polystyrene particles (PSP). Steady-state and time-resolved fluorescence measurements revealed a strong fluorescence enhancement for all dyes in ethanol−water mixtures of high water content, accompanying the formation of dye aggregates with sizes of a few hundred nm, overcoming polarity and H-bonding-induced fluorescence quenching of the chargetransfer-type emission of these PVQ dyes. The size and shape of these dye aggregates and the size of the AIE effect are controlled by the water content and the substituent-dependent torsion angle that influences the nucleation process and the packing of the molecules during aggregation. Staining of 1 μm-sized carboxy-functionalized PSP with the PVQ dyes resulted also in a considerable increase in the fluorescence quantum yield and lifetime, reflecting the combined influence of the restricted molecular motion and the reduced polarity of the dye microenvironment. KW - Spectroscopy KW - AIE KW - Aggregates KW - Nanoparticle PY - 2018 DO - https://doi.org/10.1021/acs.jpcc.8b01425 SN - 1932-7447 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. VL - 122 IS - 20 SP - 11119 EP - 11127 PB - ACS Publications AN - OPUS4-45176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kasperovich, G. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - X-ray refraction distinguishes unprocessed powder from empty pores in selective laser melting Ti-6Al-4V N2 - For the first time, X-ray refraction techniques are proven for the identification of void formation in Ti-6Al-4V parts produced by selective laser melting. The topology and volume fraction of pores are measured in samples produced with different laser energy density. Unique X-ray refraction methods identify different kinds of defects, characteristic to the regions below and above the Optimum laser energy density, namely unprocessed powder (unmolten powder particles, balling effect, and Fusion defects) from empty keyhole pores. Furthermore, it is possible to detect small inhomogeneities (voids or cracks) with sizes below the spatial resolution of optical microscopy and X-ray computed tomography. KW - Additive manufacturing KW - X-ray refraction KW - Microscopy KW - X-ray computed tomography KW - Porosity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434041 DO - https://doi.org/10.1080/21663831.2017.1409288 SN - 2166-3831 VL - 6 IS - 2 SP - 130 EP - 135 PB - Taylor & Francis Group CY - London, UK AN - OPUS4-43404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Laquai, René A1 - Nellesen, J. A1 - Tillmann, W. A1 - Kasperovich, G. A1 - Bruno, Giovanni T1 - Microstructure characterisation of advanced materials via 2D and 3D X-ray refraction techniques N2 - 3D imaging techniques have an enormous potential to understand the microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this conference paper we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. We demonstrate showcases of ceramics and composite materials, where microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. We present in situ analysis of the damage evolution in an Al/Al2O3 metal matrix composite during tensile load and the identification of void formation (different kinds of defects, particularly unsintered powder hidden in pores, and small inhomogeneity’s like cracks) in Ti64 parts produced by selective laser melting using synchrotron X-ray refraction radiography and tomography. T2 - THERMEC 2018: 10TH international conference on processing and manufacturing of advanced materials CY - Paris, France DA - 08.07.2018 KW - Additive manufacturing (AM) KW - Creep KW - Damage evolution KW - Synchrotron X-ray refraction radiography KW - Metal matrix composites PY - 2018 UR - https://www.scientific.net/MSF.941.2401 SN - 978-3-0357-1208-7 DO - https://doi.org/10.4028/www.scientific.net/MSF.941.2401 SN - 1662-9752 SN - 0255-5476 VL - 941 SP - 2401 EP - 2406 PB - Trans Tech Publications CY - Switzerland AN - OPUS4-47148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Göbel, M. A1 - Kirsch, S. A1 - Schwarze, L: A1 - Schmidt, L. A1 - Scholz, H. A1 - Haußmann, J. A1 - Klages, M. A1 - Scholta, J. A1 - Markötter, H. A1 - Alrwashdeh, S. A1 - Manke, I. A1 - Müller, Bernd R. T1 - Transient limiting current measurements for characterization of gas diffusion layers N2 - The water management in proton exchange membrane fuel cells (PEMFC) is strongly influenced by the design of the gas diffusion layers (GDL). Limiting current measurements in small-scale cells operating at high stoichiometries are useful to determine the oxygen transport resistance. The oxygen transport resistance increases, once water condenses inside the GDL. In this study a new electrochemical method for voltage loss estimation of GDL induced oxygen transport losses are presented. This new method, referred to as “transient limiting current” (TLC), is compared with the literature method. TLC allows a direct estimation of oxygen transport resistance at an arbitrarily conditioned state. This study also presents a case study of liquid water visualization of a PEM fuel cell with varying GDLs types. With the help of quasi in-situ synchrotron X-ray computed tomography and time resolved radiography measurements we investigate appearance and distribution of liquid water inside the GDLs under limiting current conditions. KW - In-situ characterization of GDLs KW - In-situ synchrotron X-ray computed tomography KW - In-situ synchrotron X-ray radiography KW - BAMline PY - 2018 DO - https://doi.org/10.1016/j.jpowsour.2018.09.003 SN - 0378-7753 SN - 1873-2755 VL - 402 SP - 237 EP - 245 PB - Elsevier B.V. AN - OPUS4-46552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Allix, M. A1 - Davis, M.J. A1 - Duran, A. A1 - Höche, T. A1 - Honma, T. A1 - Komatsu, T. A1 - Krüger, S. A1 - Mitra, I. A1 - Müller, Ralf A1 - Nakane, S. A1 - Pascual, M.J. A1 - Schmelzer, J.W. A1 - Zanotto, E.D. A1 - Zhou, S. T1 - Updated definition of glass-ceramics N2 - Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the Definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the Performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads “Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%”. KW - Glass-ceramics definition PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464711 DO - https://doi.org/10.1016/j.jnoncrysol.2018.01.033 SN - 0022-3093 SN - 1873-4812 VL - 501 SP - 3 EP - 10 PB - Elsevier B.V. AN - OPUS4-46471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, I. A1 - Moll, J. A1 - Kexel, C. A1 - Schubert, L. A1 - Tschöke, K. A1 - Prager, Jens A1 - Lugovtsova, Yevgeniya A1 - Bach, M. A1 - Vogt, T. T1 - SHM using Guided Waves – Recent Activities and Advances in Germany N2 - Issues that prevent Structural Health Monitoring (SHM) based on Guided Waves (GW) from being a part of today’s monitoring solutions in industry are not all obvious to the scientific community. To uncover and overcome these issues, scientists working on SHM and GW problems joined in an expert committee under the patronage of the German Society for Non-Destructive Testing. An initiated online survey among more than 700 experts and users reveals the hurdles hindering the practical application of GWbased SHM. Firstly, methods for proof of reliability of SHM approaches are missing. Secondly, detailed understanding of phenomenological described wave-damage interactions is needed. Additionally, there are significant unsolved implementation issues and unsolved problems of signal processing including handling of environmental influences. To enable substantial proof of reliability without unaffordable experimental effort also efficient simulation tools including realistic damage interaction are needed, enabling the joint use of experimental and simulated data to predict the capabilities of the Monitoring system. Considering these issues, the committee focusses on simulation, signal processing, as well as probability of detection and standardization. In the presented work, recent activities of the expert committee starting with survey results are summarized. An open access data basis of life-like measurements is presented to allow testing and comparison of signal processing and simulation algorithms. Finally, a strategy for efficient proof of reliability increasing the acceptance of SHM in industry and for successful Integration of SHM into real-world engineering structures is proposed. T2 - The 12th International Workshop on Structural Health Monitoring (IWSHM) CY - Stanford, California, USA DA - 10.09.2019 KW - Structural Health Monitoring KW - Ultrasonic Guided Waves KW - Non-Destructive Testing KW - Survey KW - Probability of Detection KW - Reliability PY - 2019 SP - 1 EP - 10 AN - OPUS4-49232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Welter, T. A1 - Marzok, Ulrich A1 - Deubener, J. A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Hydrogen diffusivity in sodium aluminosilicate glasses N2 - Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartzalbite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized). Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4×10−12 to 3×10−14m2 s−1 (Qz-Np) and from 4×10−13 to 3×10−15m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of Magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend. KW - Aluminosilicate glasses KW - Hydrogen diffusivity KW - Ionic porosity PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119502 VL - 521 SP - 119502 PB - Elsevier B.V. AN - OPUS4-50392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Deubener, J. A1 - Müller, Ralf A1 - Behrens, H. T1 - Statistical analysis of propagation rates of indentation-induced radial cracks N2 - Due to the stochastic nature of crack nucleation by Vickers indentation, a statistical analysis of propagation rates of 185 radial cracks was performed. Crack growth was observed directly using a video camera with high Image acquisition rate. It is found that propagation rates are controlled by the environmental reactions at the crack-tip shortly after their initiation (< 1 s). Calibration of the stress intensity KI showed that the residual stress factor χ and the exponent n of the equation KI==χPc−n (with P==load and c==crack length) are broadly distributed among the 185 analyzed cracks, ranging from 10−16 to 104 and from 0.1 to 5, respectively. For the most frequent crack, the equation KI==0.052Pc−1.47 holds. The results show that correlations of indentation-induced crack length to stress intensity necessitate the use of statistical significant data that are calibrated by the environmental reactions at the crack-tip. KW - Stress intensity factor KW - Vickers indentation KW - Subcritical crack growth KW - Soda-lime-silica glass PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119739 VL - 527 SP - 119739 PB - Elsevier B.V. AN - OPUS4-50393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balzer, R. A1 - Behrens, H. A1 - Schuth, S. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Fechtelkord, M. A1 - Deubener, J. T1 - The influence of H2O and SiO2 on the structure of silicoborate glasses N2 - To understand the impact of dissolved water on structure and properties, four boron-rich glasses of molar compositions 15-x Na2O x CaO 15 SiO2 70 B2O3 (with x=0, 7.5, 10) and 10 Na2O 15 SiO2 75 B2O3 were prepared and subsequently hydrated (up to 8 wt% H2O). Density measurements show a non-linear trend upon hydration implying large structural changes in particular at water contents<2 wt%. Near-infrared spectroscopy shows hydroxyl groups are the dominant species in all glasses upon the entire range of water content. Molecular H2O is detectable only at total water contents>2 wt%. 11B MAS NMR spectra show that the abundance of BO4 species is mainly controlled by ratio of (Na2O+CaO)/B2O3 while incorporation of water plays a minor role. Compared to borate glasses, the efficiency of formation of BO4 tetrahedra is favored by crosslinking of the network by SiO4-units. The glass transition temperatures, determined by differential thermal analysis, decreases continuously with water content due to breakage of B-O-B bonds by hydrolysis. However, compared to Silicates and aluminosilicates, the effect of dissolved water is less pronounced which can be explained by weaker B-O-B bonds in comparison to Si-O-Si bonds. KW - High pressure KW - Water speciation KW - Silicoborate glasses KW - Infrared spectroscopy KW - NMR spectroscopy PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.05.030 VL - 519 SP - 38 EP - 51 PB - Elsevier B.V. AN - OPUS4-48748 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Balzer, R. A1 - Deubener, J. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Density, elastic constants and indentation hardness of hydrous soda-lime silica glasses N2 - The effect of structural water on density, elastic constants and microhardness of water-bearing soda-lime-silica glasses of up to 21.5 mol% total water is studied. It is found that the Poisson ratio and the water content are positively correlated, while density and the elastic moduli decrease with increasing water content. Vickers hardness decreases by approximately 27% from the dry to the most hydrous glass. For water fractions <3 mol%, the dependencies are non-linear reflecting the non-linear change in the concentrations of OH and H2O molecules dissolved, whereas for water fractions >3 mol% linear dependencies are found. To distinguish the effect of structural water and environmental water, indentations were performed in toluene, nitrogen gas and air. Timedependent softening was evident for testing dry glasses in humid atmospheres as well as for tests of hydrous glasses in dry atmospheres. This indicates that the response times of dissolved water species are effectively equal in both scenarios. KW - Elastic constants KW - Soda-lime-silica KW - Glass KW - Water content KW - Microhardness PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119480 SN - 0022-3093 SN - 1873-4812 VL - 521 SP - 119480 PB - Elsevier B.V. AN - OPUS4-48758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, U. A1 - McMahon, Dino Peter A1 - Rolff, J. T1 - Exposure of the wild bee Osmia bicornis to the honey bee pathogen Nosema ceranae N2 - Wild bees are important pollinators for agricultural crops and solitary species such as Osmia bicornis are particularly suitable for pollination management. Wild bees share floral resources with managed honey bees and may be exposed to emerging infectious diseases. Although studies have explored the prevalence of pathogens in solitary wild bee species, data regarding the impact of pathogens on solitary bee health are lacking. We carried out experiments examining whether the solitary bee species O. bicornis is susceptible to infection with the emerging pathogen The results obtained indicate that N. ceranae may be able to infect O. bicornis but its impact on host fitness is negligible: survival rates did not differ between Control and inoculated bees, although male survival was marginally lower after infection. To explore the possible field-relevance of our findings, we collected wild bees near an infected and a non-infected hive and showed that N. ceranae was shared between managed and wild bees, although only the in presence of infected honey bees. The findings of the present study show that O. bicornis is susceptible to pathogen spillover and could act as a potential reservoir host for N. ceranae in pollinator networks. Additional studies on this species incorporating sublethal effects, multiple infections and other interacting stressors are warranted. KW - Wild bees KW - Nosema ceranae KW - Osmia bicornis KW - Pathogen spillover KW - Survival rates PY - 2019 DO - https://doi.org/10.1111/afe.12338 SN - 1461-9555 SN - 1461-9563 VL - 21 IS - 4 SP - 363 EP - 371 PB - Wiley AN - OPUS4-49648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bramke, K. A1 - Müller, U. A1 - McMahon, Dino Peter A1 - Rolff, J. T1 - Exposure of Larvae of the Solitary Bee Osmia bicornis to the Honey Bee Pathogen Nosema ceranae Aects Life History N2 - Wild bees are important pollinators of wild plants and agricultural crops and they are threatened by several environmental stressors including emerging pathogens. Honey bees have been suggested as a potential source of pathogen spillover. One prevalent pathogen that has recently emerged as a honey bee disease is the microsporidian Nosema ceranae. While the impacts of N. ceranae in honey bees are well documented, virtually nothing is known about its effects in solitary wild bees. The solitary mason bee Osmia bicornis is a common pollinator in orchards and amenable to Commercial management. Here, we experimentally exposed larvae of O. bicornis to food contaminated with N. ceranae and document spore presence during larval development. We measured mortality, growth parameters, and timing of pupation in a semi-field experiment. Hatched individuals were assessed for physiological state including fat body mass, wing muscle mass, and body size. We recorded higher mortality in the viable-spore-exposed group but could only detect a low number of Spores among the individuals of this treatment. Viable-spore-treated individuals with higher head capsule width had a delayed pupation start. No impact on the physiological status could be detected in hatched imagines. Although we did not find overt evidence of O. bicornis infection, our findings indicate that exposure of larvae to viable N. ceranae spores could affect bee development. KW - Bee diseases KW - Wild bees KW - Nosema ceranae KW - Osmia bicornis KW - Pathogen transmission KW - Solitary bees KW - Bee health PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496497 DO - https://doi.org/10.3390/insects10110380 VL - 10 IS - 11 SP - 380 PB - MDPI AN - OPUS4-49649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Maiwald, M. A1 - Deubener, J. A1 - Balzer, R. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses N2 - To explore the impact of ambient and structural water on static fatigue, the initiation and growth of 3279 Vickers induced median radial cracks were automatically recorded and analyzed. We find that humidity is more efficient in initiating cracks and promoting their growth than water, which is dissolved in the glass structure. In particular for slow crack growth (< 3x10-6 m s-1), tests in dry nitrogen showed a considerable decrease in the crack growth exponent with increasing water content of the glasses. On the other hand, if tests were performed in humid air, the crack growth exponent was independent of the water content of the hydrous glasses, while stress intensity decreased slightly. These observations indicate that water promotes the processes at the crack-tip regardless of its origin. However, ambient water is more efficient. KW - Indentation fracture toughness KW - Slow crack growth KW - Automated analysis KW - Hydrous glass KW - Vickers indentation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513085 DO - https://doi.org/10.3389/fmats.2020.00268 VL - 7 SP - 268 AN - OPUS4-51308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Denißen, M. A1 - Hannen, R. A1 - Itskalov, D. A1 - Biesen, L. A1 - Nirmalananthan-Budau, Nithiya A1 - Hoffmann, Katrin A1 - Reiss, G. J. A1 - Resch-Genger, Ute A1 - Müller, T. J. J. T1 - One-pot synthesis of a white-light emissive bichromophore operated by aggregation-induced dual emission (AIDE) and partial energy transfer N2 - Merocyanine–triarylamine bichromophores are readily synthesized by sequentially Pd-catalyzed insertion alkynylation–Michael–Suzuki four-component reactions. White-light emissive systems form upon aggregation in 1 : 99 and 0.1 : 99.9 vol% CH2Cl2–cyclohexane mixtures, ascribed to aggregation-induced dual emission (AIDE) in combination with partial energy transfer between both chromophore units as supported by spectroscopic studies. KW - Energy transfer KW - Nano KW - Nanoparticle KW - Photoluminescence KW - Fluorescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Dye KW - Enhancement KW - Particle KW - Polarity KW - AIE KW - Aggregation KW - Aggregation-induced emission KW - Solid state emission KW - Merocyanine PY - 2020 DO - https://doi.org/10.1039/d0cc03451g VL - 56 IS - 54 SP - 7407 PB - Royal Society of Chemistry AN - OPUS4-50936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faghani, A. A1 - Gholami, M. F. A1 - Trunk, M. A1 - Müller, J. A1 - Pachfule, P. A1 - Vogl, S. A1 - Donskyi, Ievgen A1 - Li, M. A1 - Nickl, Philip A1 - Shao, J. A1 - Huang, M. R. S. A1 - Unger, Wolfgang A1 - Arenal, R. A1 - Koch, C. T. A1 - Paulus, B. A1 - Rabe, J. P. A1 - Thomas, A. A1 - Haag, R. A1 - Adeli, M. T1 - Metal-Assisted and Solvent-Mediated Synthesis of Two-Dimensional Triazine Structures on Gram Scale N2 - Covalent triazine frameworks are an emerging material class that have shown promising performance for a range of applications. In this work, we report on a metal-assisted and solvent-mediated reaction between calcium carbide and cyanuric chloride, as cheap and commercially available precursors, to synthesize two-dimensional triazine structures (2DTSs). The reaction between the solvent, dimethylformamide, and cyanuric chloride was promoted by calcium carbide and resulted in dimethylamino-s-triazine intermediates, which in turn undergo nucleophilic substitutions. This reaction was directed into two dimensions by calcium ions derived from calcium carbide and induced the formation of 2DTSs. The role of calcium ions to direct the two-dimensionality of the final structure was simulated using DFT and further proven by synthesizing molecular intermediates. The water content of the reaction medium was found to be a crucial factor that affected the structure of the products dramatically. While 2DTSs were obtained under anhydrous conditions, a mixture of graphitic material/2DTSs or only graphitic material (GM) was obtained in aqueous solutions. Due to the straightforward and gram-scale synthesis of 2DTSs, as well as their photothermal and photodynamic properties, they are promising materials for a wide range of future applications, including bacteria and virus incapacitation. KW - XPS KW - Triazine KW - 2D PY - 2020 DO - https://doi.org/10.1021/jacs.0c02399 VL - 142 IS - 30 SP - 12976 EP - 12986 PB - ACS American Chemical Society AN - OPUS4-51203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herzel, Hannes A1 - Dombinov, V. A1 - Vogel, Christian A1 - Willbold, S. A1 - Levandowski, G. V. A1 - Meiller, M. A1 - Müller, F. A1 - Zang, J. W. A1 - da Fonseca-Zang, W. A. A1 - Jablonowski, N. D. A1 - Schrey, S. D. A1 - Adam, Christian T1 - Soybean Fertilized by P-Phases from Bagasse-Based Materials: P-Extraction Procedures, Diffusive Gradients in Thin Films (DGT), and X-ray Diffraction Analysis (XRD) N2 - The Brazilian sugarcane industry produced around 173 million tons (Mt) of bagasse in 2018. Bagasse is a by-product of juice extraction for ethanol and sugar production and is combusted in order to generate power, producing up to 10 Mt of ash per year. This ash contains various concentrations of plant nutrients, which allow the ash to be used as a crop fertilizer. However, the concentration and extractability of phosphorus (P), an essential plant nutrient, are low in bagasse ash. To increase the P content, we co-gasified and co-combusted bagasse with P-rich chicken manure. The resulting ash was thermochemically post-treated with alkali additives (Na2SO4 and K2SO4) to increase the availability of P to plants. We aimed to: (i) investigate the effect of thermochemical post-treatment of co-gasification residue and co-combustion ash on P availability to soybeans, (ii) explore the potential of chemical extraction methods (citric acid, neutral ammonium citrate, formic acid, and Mehlich-I) and diffusive gradients in thin films (DGT) to predict the availability of P to soybeans, and (iii) identify the responsible P-phases using X-ray diffraction . We evaluated P availability to soybeans growing in Brazilian Oxisol soil in two independent greenhouse pot experiments. The positive effect of thermochemical treatment on P availability from gasification residue was confirmed through the observation of increased P uptake and biomass in soybean plants. These findings were confirmed by chemical extraction methods and DGT. The gasification residue contained whitlockite as its main P-bearing phase. Thermochemical post-treatment converted whitlockite into highly soluble CaNaPO4. In contrast, co-combustion ash already contained highly soluble Ca(Na,K)PO4 as its main P-bearing phase, making thermochemical post-treatment unnecessary for increasing P availability. In conclusion, increased extractability and availability of P for soybeans were closely connected to the formation of calcium alkali phosphate. Our findings indicate that this combined methodology allows for the prediction of P-fertilization effects of ash. KW - Sugar cane bagasse KW - Chicken manure ash KW - Thermochemical treatment KW - Nutrient KW - Plant availability PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509735 DO - https://doi.org/10.3390/agronomy10060895 VL - 10 SP - 895 EP - 6 PB - MDPI AN - OPUS4-50973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balzer, R. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Kiefer, P. A1 - Deubener, J. A1 - Fechtelkord, M. T1 - Water in Alkali Aluminosilicate Glasses N2 - To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses. KW - NMR spectroscopy KW - Alkali aluminosilicate glasses KW - Water speciation KW - Glass transition KW - Infrared spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509497 DO - https://doi.org/10.3389/fmats.2020.00085 VL - 7 SP - 85 AN - OPUS4-50949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Deubener, J. A1 - Balzer, R. A1 - Behrens, H. T1 - Crack Growth in Hydrous Soda-Lime Silicate Glass N2 - Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of b-relaxation intensity indicating more energy Dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water. KW - Internal friction KW - Soda-lime silicate glass KW - Water content KW - Stable crack growth KW - DCB geometry KW - Stress intensity factor PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506829 DO - https://doi.org/10.3389/fmats.2020.00066 VL - 7 SP - Articel 66 AN - OPUS4-50682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Schneider, J. A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - Using SXRR to Probe the Nature of Discontinuities in SLM Additive Manufactured Inconel 718 Specimens N2 - The utilization of additive manufacturing (AM) to fabricate robust structural components relies on understanding the nature of internal anomalies or discontinuities, which can compromise the structural integrity. While some discontinuities in AM microstructures stem from similar mechanisms as observed in more traditional processes such as casting, others are unique to the AM process. Discontinuities in AM are challenging to detect, due to their submicron size and orientation dependency. Toward the goal of improving structural integrity, minimizing discontinuities in an AM build requires an understanding of the mechanisms of formation to mitigate their occurrence. This study utilizes various techniques to evaluate the shape, size, nature and distribution of discontinuities in AM Inconel 718, in a non-hot isostatic pressed (HIPed) as-built, non-HIPed and direct age, and HIPed with two step age samples. Non-destructive synchrotron radiation refraction and transmission radiography (SXRR) provides additional information beyond that obtained with destructive optical microscopy. SXRR was able to distinguish between voids, cracks and lack of melt in, due to its sensitivity to the orientation of the discontinuity. KW - Additive manufacturing KW - X-ray refraction radiography KW - INCONEL 718 KW - Selective laser melting PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509836 DO - https://doi.org/10.1007/s11661-020-05847-5 SN - 1543-1940 VL - 51 IS - 8 SP - 4146 EP - 4157 PB - Springer AN - OPUS4-50983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biesen, L. A1 - Nirmalananthan-Budau, Nithiya A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Müller, T. J. J. T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics. Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red. KW - Nano KW - Nanoparticle KW - Photoluminescence KW - Fluorescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - dye KW - Enhancement KW - Particle KW - Polarity KW - AIE KW - Aggregation KW - Aggregation-induced emission KW - Solid state emission PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072 DO - https://doi.org/10.1002/anie.201916396 VL - 59 IS - 25 SP - 10037 EP - 10041 PB - Wiley Online Libary AN - OPUS4-50907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyerhofer, F. A1 - Dissinger, F. A1 - Weigert, Florian A1 - Jungclaus, J. A1 - Müller-Caspary, K. A1 - Waldvogel, S. R. A1 - Resch-Genger, Ute A1 - Voss, T. T1 - Citric Acid Based Carbon Dots with Amine Type Stabilizers: pHSpecific N2 - We report the synthesis and spectroscopic characteristics of two different sets of carbon dots (CDs) formed by hydrothermal reaction between citric acid and polyethylenimine (PEI) or 2,3-diaminopyridine (DAP). Although the formation of amide-based species and the presence of citrazinic acid type derivates assumed to be responsible for a blue emission is confirmed for both CDs by elemental analysis, infrared spectroscopy, and mass spectrometry, a higher abundance of sp2-hybridized nitrogen is observed for DAP-based CDs, which causes a red-shift of the n-π* absorption band relative to the one of PEI-based CDs. These CD Systems possess high photoluminescence quantum yields (QY) of ∼40% and ∼48% at neutral pH, demonstrating a possible tuning of the optical properties by the amine precursor. pH-Dependent spectroscopic studies revealed a drop in QY to < 9% (pH ∼ 1) and < 21% (pH ∼ 12) for both types of CDs under acidic and basic conditions. In contrast, significant differences in the pHdependency of the n-π* transitions are found for both CD types which are ascribed to different (de)protonation sequences of the CD-specific fluorophores and functional groups using Zeta potential analysis. KW - Fluorescence KW - Particle KW - Nano KW - Surface group analysis KW - Carbon dot KW - C-dot KW - Fluorescent probe KW - Quantum yield KW - Synthesis KW - IR KW - MS KW - Polymer KW - Ligand PY - 2020 DO - https://doi.org/10.1021/acs.jpcc.9b11732 VL - 124 IS - 16 SP - 8894 EP - 8904 PB - American Chemical Society AN - OPUS4-50813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cant, D. J. H. A1 - Minelli, C. A1 - Sparnacci, K. A1 - Müller, Anja A1 - Kalbe, H. A1 - Stoger-Pollach, M. A1 - Unger, Wolfgang A1 - Werner, W. S. M. A1 - Shard, A. G. T1 - Surface-Energy Control and Characterization of Nanoparticle Coatings N2 - Accurate and reproducible measurement of the structure and properties of high-value nanoparticles is extremely important for their commercialization. A significant proportion of engineered nanoparticle systems consist of some form of nominally core-shell structure, whether by design or unintentionally. Often, these do not form an ideal core-shell structure, with typical deviations including polydispersity of the core or shell, uneven or incomplete shells, noncentral cores, and others. Such systems may be created with or without intent, and in either case an understanding of the conditions for formation of such particles is desirable. Precise determination of the structure, composition, size, and shell thickness of such particles can prove challenging without the use of a suitable range of characterization techniques. Here, the authors present two such polymer core-shell nanoparticle systems, consisting of polytetrafluoroethylene cores coated with a range of thicknesses of either polymethylmethacrylate or polystyrene. By consideration of surface energy, it is shown that these particles are expected to possess distinctly differing coating structures, with the polystyrene coating being incomplete. A comprehensive characterization of these systems is demonstrated, using a selection of complementary techniques including scanning electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, dynamic light scattering, differential centrifugal sedimentation, and X-ray photoelectron spectroscopy. By combining the results provided by these techniques, it is possible to achieve superior characterization and understanding of the particle structure than could be obtained by considering results separately. KW - Nanoparticles KW - Core-shell KW - XPS KW - Size KW - Thickness KW - Damage PY - 2020 DO - https://doi.org/10.1021/acs.jpcc.0c02161 VL - 124 IS - 20 SP - 11200 EP - 11211 PB - ACS CY - Washington DC AN - OPUS4-50899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirilina, E. A1 - Helbling, S. A1 - Morawski, M. A1 - Pine, K. A1 - Reimann, K. A1 - Jankuhn, S. A1 - Dinse, J. A1 - Deistung, A. A1 - Reichenbach, J. R. A1 - Trampel, R. A1 - Geyer, S. A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Arendt, T. A1 - Bazin, P.-L. A1 - Weiskopf, N. T1 - Superficial white matter imaging: Contrast mechanisms and whole-brain in vivo mapping N2 - Superficial white matter (SWM) contains the most cortico-cortical white matter connections in the human brain encompassing the short U-shaped association fibers. Despite its importance for brain connectivity, very little is known about SWM in humans, mainly due to the lack of noninvasive imaging methods. Here, we lay the groundwork for systematic in vivo SWM mapping using ultrahigh resolution 7 T magnetic resonance imaging. Using biophysical modeling informed by quantitative ion beam microscopy on postmortem brain tissue, we demonstrate that MR contrast in SWM is driven by iron and can be linked to the microscopic iron distribution. Higher SWM iron concentrations were observed in U-fiber–rich frontal, temporal, and parietal areas, potentially reflecting high fiber density or late myelination in these areas. Our SWM mapping approach provides the foundation for systematic studies of interindividual differences, plasticity, and pathologies of this crucial structure for cortico-cortical connectivity in humans. KW - Magnetic resonance imaging KW - Laser ablation KW - ICP-MS KW - Brain KW - Imaging PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514430 DO - https://doi.org/10.1126/sciadv.aaz9281 SN - 2375-2548 VL - 6 IS - 41 SP - eaaz9281 PB - American Association for the Advancement of Science (Science/AAAS) CY - Washington, DC, USA AN - OPUS4-51443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Baer, D. R. A1 - Cant, D. J. H. A1 - Castner, D. G. A1 - Ceccone, G. A1 - Engelhard, M. H. A1 - Karakoti, A. S. A1 - Müller, Anja ED - Hodoroaba, Vasile-Dan ED - Unger, Wolfgang ED - Shard, A. G. T1 - Preparation of nanoparticles for surface analysis N2 - A variety of methods used to prepare nano-objects for surface analysis are described along with information about when they might be best applied. Intrinsic properties of NPs which complicate their characterization and need to be considered when planning for surface or other analyses of NPs are identified, including challenges associated with reproducible synthesis and functionalization of the particles as well as their dynamic nature. The relevant information about the sample preparation processes, along with analysis details and data that need to be added to the collection of material provenance information is identified. Examples of protocols that have been successfully used for preparation of nano-objects for surface analysis are included in an annex. KW - Sample preparation KW - Nanoparticles KW - Surface chemistry KW - XPS KW - Dynamic behavior KW - Nano-object KW - Surface analysis PY - 2020 SN - 978-0-12-814182-3 DO - https://doi.org/10.1016/B978-0-12-814182-3.00018-3 SP - 295 EP - 347 PB - Elsevier CY - Amsterdam AN - OPUS4-50186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunz, C. A1 - Bonse, Jörn A1 - Spaltmann, Dirk A1 - Neumann, C. A1 - Turchanin, A. A1 - Bartolomé, J. F. A1 - Müller, F. A. A1 - Gräf, S. T1 - Tribological performance of metal-reinforced ceramic composites selectively structured with femtosecond laser-induced periodic surface structures N2 - The impact of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on tribological properties was investigated for metal-reinforced ceramic composites (Al2O3-ZrO2-Nb). For this purpose, the metallic niobium (Nb) phase was selectively structured with LIPSS in an air environment with different values of the fs-laser peak fluence by near-infrared fs-laser radiation (λ = 1025 nm, τ = 300 fs, frep = 1 kHz), taking advantage of the different light absorption behavior of ceramic and metal. The tribological performance was evaluated by reciprocating sliding tests in a ball-on-disc configuration using Ringer's solution as lubricant. The surfaces were characterized before and after laser irradiation by optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and by measuring the contact angle with Ringer's solution. The LIPSS formation resulted in an increased wetting of the surface with the lubricant. Moreover, the selectively structured composite surfaces revealed a coefficient of friction significantly reduced by a factor of ~3 when compared to the non-irradiated surface. Furthermore, the formation of a laser-induced oxidation layer was detected with NbO as the most prominent oxidation state. Selectively structured composites with outstanding mechanical properties and enhanced tribological performance are of particular interest for biomedical applications. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Ceramic matrix composites KW - Tribology PY - 2020 DO - https://doi.org/10.1016/j.apsusc.2019.143917 SN - 0169-4332 SN - 1873-5584 VL - 499 IS - 1 SP - 143917 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-49255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kasperovich, G. A1 - Requena, G. A1 - Haubrich, J. A1 - Bruno, Giovanni T1 - Classification of defect types in SLM Ti-6Al-V4 by X-ray refraction topography N2 - Porosity in additively manufactured materials, such as laser powder bed fusion Ti-Al6-V4, can play an important role in their mechanical performance. Not only the total porosity but also the shape/morphology of the individual pores need to be considered. Therefore, it is necessary to determine the distributions of different defect types (especially fusing defects and keyhole pores) and their dependence on process parameters. We show that synchrotron X-ray refraction radiography allows analysis of large samples (up to several millimeters) without compromising the detectability of submicrometer defects. Correspondingly, a classification tool is introduced that is able to quantitatively distinguish defects such as keyhole pores and binding defects with a confidence level of 94 %, even when the shape cannot be discerned because of limited spatial resolution. KW - Additive manufacturing KW - Selective laser melting KW - X-ray refraction KW - Microscopy KW - Porosity KW - X-ray computed tomography KW - BAMline KW - Synchrotron Radiation PY - 2020 DO - https://doi.org/10.1520/MPC20190080 SN - 2379-1365 VL - 9 IS - 1 SP - 82 EP - 93 PB - ASTM International CY - West Conshohocken, PA AN - OPUS4-50470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf A1 - Hille, Falk A1 - Said, Samir A1 - Sterthaus, Jens A1 - Müller, Karsten A1 - Quercetti, Thomas A1 - Wille, Frank A1 - Paffenholz, J.-A. A1 - Baeßler, Matthias ED - Papadrakakis, M. ED - Fragiadakis, M. ED - Papadimitriou, C. T1 - Implementing a Structural Health Monitoring system using digital models of the BAM large drop test facility in Horstwalde N2 - At the Bundesanstalt für Materialforschung und -prüfung (BAM) full scale specimens for nuclear transport and storage containers (casks) are tested for their structural integrity in a series of drop tests on the Test Site Technical Safety in Horstwalde, 50 km south of Berlin. These drop tests cause a major stress not only on the casks, but also on the steel tower structure of the test facility, itself. The load pattern makes the structure very interesting for detailed investigation. The focus of the monitoring lies on the bolted joints of the flange connections that are a typical connection for cylindrical elements if welding is technical or economical unfavorable. The definition of the monitoring takes was done by investigating the existing documents and inspection results accompanied by building an initial digital representation of the structure, consisting of two finite element (FE) models and a geometrical 3D point cloud representation. As a first step the structures behavior during static and dynamic loading was analyzed using measurement data and an updated numerical FE Model. The idea behind is to use models for a digital planning and operation/evaluation of the structural health monitoring. A static FE simulation and a dynamic FE simulation are generated, to investigate how the structure behaves under the load conditions. T2 - XI International Conference on Structural Dynamics (EuroDyn 2020) CY - Online meeting DA - 23.11.2020 KW - Structural Health Monitoring KW - Drop Tests KW - System Identification KW - Digital Models KW - BIM PY - 2020 UR - https://generalconferencefiles.s3-eu-west-1.amazonaws.com/eurodyn_2020_ebook_procedings_vol1.pdf SN - 978-618-85072-0-3 VL - 1 SP - 1293 EP - 1304 PB - Institute of Structural Analysis and Antiseismic Research CY - Athen AN - OPUS4-51592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Welter, T. A1 - Müller, Ralf A1 - Deubener, J. A1 - Marzok, Ulrich A1 - Reinsch, Stefan T1 - Hydrogen Permeation Through Glass N2 - Physical storage of gaseous hydrogen under high-pressure in glassy micro-containers such as spheres and capillaries is a promising concept for enhancing safety and the volumetric capacity of mobile hydrogen storage systems. As very low permeation through the container wall is required for storage of compressed hydrogen, development of glasses of minimal hydrogen permeability is needed. For this purpose, one has to understand better the dependence of hydrogen permeability on glass structure. The paper points out that minimizing the accessible free volume is as one strategy to minimize hydrogen permeability. Based on previously measured and comprehensive literature data, it is shown that permeation is independently controlled by ionic porosity and network modifier content. Thus, ionic porosity in modified and fully polymerized networks can be decreased equally to the lowest hydrogen permeability among the glasses under study. Applying this concept, a drop of up to 30,000 with respect to the permeation of hydrogen molecules through silica glass is attainable. KW - Ionic porosity KW - hydrogen storage KW - Glass KW - Permeability KW - Solubility KW - Diffusivity PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513927 DO - https://doi.org/10.3389/fmats.2019.00342 VL - 6 SP - Article 342 AN - OPUS4-51392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liens, A. A1 - Reveron, H. A1 - Douillard, T. A1 - Blanchard, N. A1 - Lughi, V. A1 - Sergo, V. A1 - Laquai, René A1 - Müller, Bernd R. A1 - Bruno, Giovanni A1 - Schomer, S. A1 - Fürderer, T. A1 - Adolfsson, E. A1 - Courtois, N. A1 - Swain, M. A1 - Chevalier, J. T1 - Phase transformation induces plasticity with negligible damage in ceria-stabilized zirconia-based ceramics N2 - Ceramics and their composites are in general brittle materials because they are predominantly made up of ionic and covalent bonds that avoid dislocation motion at room temperature. However, a remarkable ductile behavior has been observed on newly developed 11 mol.% ceria-stabilized zirconia (11Ce-TZP) composite containing fine alumina (8 vol.% Al2O3) and elongated strontium hexa-aluminate (8 vol.% SrAl12O19) grains. The as-synthesized composite also has shown full resistance to Low Temperature Degradation (LTD), relatively high strength and exceptionally high Weibull modulus, allowing its use in a broader range of biomedical applications. In this study, to deepen the understanding of plastic deformation in Ce-TZP based composites that could soon be used for manufacturing dental implants, different mechanical tests were applied on the material, followed by complete microstructural characterization. Distinct from pure Ce-TZP material or other zirconia-based ceramics developed in the past, the material here studied can be permanently strained without affecting the Young modulus, indicating that the ductile response of tested samples cannot be associated to damage occurrence. This ductility is related to the stress-induced tetragonal to monoclinic (t-m) zirconia phase transformation, analogue to Transformation-Induced Plasticity (TRIP) steels, where retained austenite is transformed to martensite. The aim of this study is to corroborate if the observed plasticity can be associated exclusively to the zirconia t-m phase transformation, or also to microcraking induced by the transformation. The t-m transformed-zones produced after bending and biaxial tests were examined by X-ray refraction and SEM/TEM coupled with Raman. The results revealed that the observed elastic-plastic behavior occurs without extensive microcracking, confirming a purely elastic-plastic behavior driven by the phase transformation (absence of damage). KW - Zirconia KW - Ceria KW - Ceramic matrix composite KW - Plasticity KW - Phase transformation KW - X-Ray Refraction PY - 2020 UR - http://www.sciencedirect.com/science/article/pii/S1359645419307177 DO - https://doi.org/10.1016/j.actamat.2019.10.046 SN - 1359-6454 VL - 183 SP - 261 EP - 273 PB - Elsevier Ltd. AN - OPUS4-49740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Müller, Anja A1 - Radnik, Jörg A1 - Hachenberger, Y. A1 - Jungnickel, H. A1 - Laue, P. A1 - Luch, A. A1 - Tentschert, J. T1 - Preparation of Nanoparticles for ToF-SIMS and XPS Analysis N2 - Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, chemistry, and their potential to enable advanced materials. To effectively understand and regulate the physico-chemical properties and potential adverse effects of nanoparticles, validated measurement procedures for the various properties of nanoparticles need to be developed. While procedures for measuring nanoparticle size and size Distribution are already established, standardized methods for analysis of their surface chemistry are not yet in place, although the influence of the surface chemistry on nanoparticle properties is undisputed. In particular, storage and preparation of nanoparticles for surface analysis strongly influences the analytical results from various methods, and in order to obtain consistent results, sample preparation must be both optimized and standardized. In this contribution, we present, in detail, some standard procedures for preparing nanoparticles for surface analytics. In principle, nanoparticles can be deposited on a suitable substrate from suspension or as a powder. Silicon (Si) Wafers are commonly used as substrate, however, their cleaning is critical to the process. For sample preparation from suspension, we will discuss drop-casting and spin-coating, where not only the cleanliness of the substrate and purity of the suspension but also its concentration play important roles for the success of the preparation methodology. For nanoparticles with sensitive ligand shells or coatings, deposition as powders is more suitable, although this method requires particular care in fixing the sample. KW - Titania nanoparticles KW - X-ray photoelectron spectroscopy KW - Secondary ion mass spectrometry KW - Surface chemisttry PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520103 UR - https://www.jove.com/video/61758 DO - https://doi.org/10.3791/61758 VL - 163 SP - e61758 AN - OPUS4-52010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biesen, L. A1 - May, L. A1 - Nirmalananthan-Budau, Nithiya A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Müller, T. J. J. T1 - Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines N2 - Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution patterntunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors. KW - Dye KW - Fluorescence KW - Aggregation induced emission KW - Signal enhancement KW - Energy transfer KW - Switch KW - Sensor KW - Quantum yield KW - Lifetime KW - Photophysics KW - Synthesis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531123 DO - https://doi.org/10.1002/chem.202102052 VL - 27 IS - 53 SP - 13426 EP - 13434 PB - Wiley-VCH AN - OPUS4-53112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cant, D. J. H. A1 - Müller, Anja A1 - Clifford, C. A. A1 - Unger, Wolfgang A1 - Shard, A. G. T1 - Summary of ISO/TC 201 Technical Report 23173—Surface chemical analysis—Electron spectroscopies—Measurement of the thickness and composition of nanoparticle coatings N2 - ISO Technical Report 23173 describes methods by which electron spectroscopies, including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and synchrotron techniques, can be employed to calculate the Coating thicknesses and compositions of nanoparticles. The document has been developed to review and outline the current state-of-the-art for such measurements. Such analyses of core–shell nanoparticles are common within the literature, however the methods employed are varied; the relative advantages and disadvantages of These methods, and the optimal usage of each may not be clear to the general analyst. ISO Technical Report 23173 aims to clarify the methods that are available, describe them in clear terms, exhibit examples of their use, and highlight potential issues users may face. The information provided should allow analysts of electron spectroscopy data to make clear choices regarding the appropriate analysis of electron spectroscopy data from coated nanoparticle systems and provide a basis for understanding and comparing results from different methods and systems. KW - Electron spectroscopy KW - Core-shell KW - Nanoparticles KW - ISO 23173 KW - XPS KW - Thickness KW - Composition PY - 2021 DO - https://doi.org/10.1002/sia.6987 SN - 0142-2421 VL - 53 IS - 10 SP - 893 EP - 899 PB - John Wiley & Sons Ltd AN - OPUS4-52976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Laquai, René A1 - Müller, Bernd R. A1 - Paciornik, S. A1 - Horvath, J. A1 - Tushtev, K. A1 - Rezwan, K. A1 - Bruno, Giovanni T1 - Evolution of Damage in All-Oxide Ceramic Matrix Composite After Cyclic Loading N2 - While structural ceramics usually display a brittle mechanical behavior, their composites may show nonlinearities, mostly due to microcracking. Herein, the stiffness evolution of a sandwich-like laminate of an Al2O3 15%vol. ZrO2 matrix reinforced with Nextel 610 fibers is studied as a function of number of cycles N in tension. The stiffness of the composite degrades with increasing N, indicating microcracking. However, synchrotron X-ray refraction radiography shows that the internal specific surface of such cracks varies differently. A modeling strategy is developed for the calculation of the equivalent stiffness of mixtures (first the matrix and then the sandwich), based on the Voigt and Reuß schemes. The Bruno–Kachanov model is then used to estimate the initial microcrack density in the matrix (due to the thermal expansion mismatch) and the amount of microcracking increase upon cyclic loading. The stiffness in the composite degrades dramatically already after 20 000 cycles but then remains nearly constant. The combination of mechanical testing, quantitative imaging analysis, and modeling provides insights into the damage mechanisms acting: microcrack propagation is more active than microcrack initiation upon cyclic loading, but the second also occurs. This scenario is similar but not equal to previous results on porous and microcracked ceramics. KW - Ceramic matrix composites KW - Homogenization schemes KW - Microcracking KW - Nonlinear behavior KW - Synchrotron X-ray refraction radiography PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534541 DO - https://doi.org/10.1002/adem.202100763 SN - 1527-2648 SN - 1438-1656 VL - 24 IS - 6 SP - 2100763 -1 EP - 2100763 -13 PB - VCH GmbH CY - Weinheim AN - OPUS4-53454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wipfler, B. A1 - Bradler, S. A1 - Büsse, S. A1 - Hammel, J. A1 - Müller, Bernd R. A1 - Pass, G. T1 - Evolutionary morphology of the antennal heart in stick and leaf insects (Phasmatodea) and webspinners (Embioptera) (Insecta: Eukinolabia) N2 - The morphology of the antennal hearts in the head of Phasmatodea and Embioptera was investigated with particular reference to phylogenetically relevant key taxa. The antennal circulatory organs of all examined species have the same basic construction: they consist of antennal vessels that are connected to ampullae located in the head near the antenna base. The ampullae are pulsatile due to associated muscles, but the points of attachment differ between the species studied. All examined Phasmatodea species have a Musculus (M.) interampullaris which extends between the two ampullae plus a M. ampulloaorticus that runs from the ampullae to the anterior end of the aorta; upon contraction, all these muscles dilate the lumina of both ampullae at the same time. In Embioptera, only the australembiid Metoligotoma has an M. interampullaris. All other studied webspinners instead have a M. ampullofrontalis which extends between the ampullae and the frontal region of the head capsule; these species do not have M. ampulloaorticus. Outgroup comparison indicates that an antennal heart with a M. interampullaris is the plesiomorphic character state among Embioptera and the likely ground pattern of the taxon Eukinolabia. Antennal hearts with a M. ampullofrontalis represent a derived condition that occurs among insects only in some embiopterans. These findings help to further clarify the controversially discussed internal phylogeny of webspinners by supporting the view that Australembiidae are the sister group of the remaining Embioptera. KW - Phylogeny KW - Polyneoptera KW - Metoligotoma PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527795 DO - https://doi.org/10.1007/s00435-021-00526-4 SN - 1432-234X VL - 140 IS - 3 SP - 331 EP - 340 PB - Springer AN - OPUS4-52779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaeger, Carsten A1 - Ritter, D. A1 - Goeritzer, M. A1 - Thiele, A. A1 - Blumrich, A. A1 - Beyhoff, N. A1 - Luettges, K. A1 - Smeir, E. A1 - Kasch, J. A1 - Grune, J. A1 - Müller, O. A1 - Klopfleisch, R. A1 - Foryst-Ludwig, A. A1 - Kintscher, U. T1 - Liver X Receptor Agonist AZ876 Induces Beneficial Endogenous Cardiac Lipid Reprogramming and Protects Against Isoproterenol-Induced Cardiac Damage N2 - Background - It is known that dietary intake of polyunsaturated fatty acids may improve cardiac function. However, relatively high daily doses are required to achieve sufficient cardiac concentrations of beneficial omega‐3 fatty acids. The liver X receptor (LXR) is a nuclear hormone receptor and a crucial regulator of lipid homeostasis in mammals. LXR activation has been shown to endogenously reprogram cellular lipid profiles toward increased polyunsaturated fatty acids levels. Here we studied whether LXR lipid reprogramming occurs in cardiac tissue and exerts cardioprotective actions. Methods and Results - Male 129SV mice were treated with the LXR agonist AZ876 (20 µmol/kg per day) for 11 days. From day 6, the mice were injected with the nonselective β‐agonist isoproterenol for 4 consecutive days to induce diastolic dysfunction and subendocardial fibrosis while maintaining systolic function. Treatment with isoproterenol led to a marked impairment of global longitudinal strain and the E/e' ratio of transmitral flow to mitral annular velocity, which were both significantly improved by the LXR agonist. Histological examination showed a significant reduction in isoproterenol‐induced subendocardial fibrosis by AZ876. Analysis of the cardiac lipid composition by liquid chromatography‐high resolution mass spectrometry revealed a significant increase in cardiac polyunsaturated fatty acids levels and a significant reduction in saturated fatty acids by AZ876. Conclusions - The present study provides evidence that the LXR agonist AZ876 prevents subendocardial damage, improves global longitudinal strain and E/e' in a mouse model of isoproterenol‐induced cardiac damage, accompanied by an upregulation of cardiac polyunsaturated fatty acids levels. Cardiac LXR activation and beneficial endogenous cardiac lipid reprogramming may provide a new therapeutic strategy in cardiac disease with diastolic dysfunction. KW - Heart failure KW - Lipids KW - Liver X receptor KW - Diastolic dysfunction KW - Nuclear receptor PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529352 DO - https://doi.org/10.1161/JAHA.120.019473 VL - 10 IS - 14 SP - e019473 AN - OPUS4-52935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Rouxel, T. A1 - Behrens, H. A1 - Deubener, J. A1 - Müller, Ralf T1 - Vacuum crack growth in alkali silicate glasses N2 - Crack growth velocity in alkali silicate glasses was measured in vacuum across 10 orders of magnitude with double cantilever beam technique. Measured and literature crack growth data were compared with calculated intrinsic fracture toughness data obtained from Young´s moduli and the theoretical fracture surface energy estimated from chemical bond energies. Data analysis reveals significant deviations from this intrinsic brittle fracture behavior. These deviations do not follow simple compositional trends. Two opposing processes may explain this finding: a decrease in the apparent fracture surface energy due to stress-induced chemical changes at the crack tip and its increase due to energy dissipation during fracture. KW - Silicate glass KW - Brittle fracture KW - Crack growth KW - Calculated intrinsic fracture toughness PY - 2021 DO - https://doi.org/10.1016/j.jnoncrysol.2021.121094 SN - 0022-3093 VL - 572 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-53144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - Müller, Ralf A1 - Waurischk, Tina A1 - Behrens, H. A1 - Deubener, J. T1 - Crack growth in borate and silicate glasses: Stress-corrosion susceptibility and hydrolytic resistance N2 - A double cantilever beam technique in air equipped with ultrasound modulation was used to measure the crack velocity v in borate and silicate glasses. In all glasses v and the stress intensity KI followed the empirical correlation v ~ KIn. Indicated by its smallest KI at v = 1 μm s − 1, KI* = 0.27 MPa m0.5, the silicoborate glass containing 70 mol% B2O3 was found most susceptible to stress-corrosion enhanced crack growth. Contrarily, the sodium calcium magnesium silicate glass appeared least susceptible with KI* = 0.57 MPa m0.5. No clear correlation is evident between KI*, reflecting the stress-corrosion susceptibility, and the hydrolytic resistance for all glasses under study, but values of n obtained from the present study and taken from previous literature for 35 glasses tend to decrease with increasing network modifier ion fraction. Energy dissipation during stress-corrosion enhanced crack propagation is assumed to cause this trend. KW - DCB KW - Alkali and alkaline earth silicate and borate glass KW - Crack growth in air KW - Stress-corrosion KW - Stress intensity PY - 2021 DO - https://doi.org/10.1016/j.jnoncrysol.2020.120414 VL - 551 SP - 120414 PB - Elsevier B.V. AN - OPUS4-51393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biesen, L. A1 - Krenzer, J. A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Müller, Th. J. J. T1 - Asymmetrically bridged aroyl-S,N-ketene acetalbased multichromophores with aggregationinduced tunable emission N2 - Asymmetrically bridged aroyl-S,N-ketene acetals and aroyl-S,N-ketene acetal multichromophores can be readily synthesized in consecutive three-, four-, or five-component syntheses in good to excellent yields by several successive Suzuki-couplings of aroyl-S,N-ketene acetals and bis(boronic)acid esters. Different aroyl-S,N-ketene acetals as well as linker molecules yield a library of 23 multichromophores with substitution and linker pattern-tunable emission properties. This allows control of different communication pathways between the chromophores and of aggregation-induced emission (AIE) and energy transfer (ET) properties, providing elaborate aggregation-based fluorescence switches. KW - Dye KW - Aggregation KW - Aggregation induced emission KW - Signal enhancement KW - Energy transfer KW - Switch KW - Sensor KW - Quantum yield KW - Lifetime KW - Photophysics KW - Sythesis KW - Nanaoparticle PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550719 DO - https://doi.org/10.1039/d2sc00415a VL - 13 SP - 5374 EP - 5381 PB - Royal Society of Chemistry AN - OPUS4-55071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tielemann, Christopher A1 - Reinsch, Stefan A1 - Maaß, Robert A1 - Deubener, J. A1 - Müller, Ralf T1 - Internal nucleation tendency and crystal surface energy obtained from bond energies and crystal lattice data N2 - We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses. KW - Glass KW - Nucleation tendency KW - Fracture surface energy KW - Crystal lattice KW - Bond energy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548814 DO - https://doi.org/10.1016/j.nocx.2022.100093 SN - 2590-1591 VL - 14 SP - 1 EP - 5 PB - Elsevier B.V. AN - OPUS4-54881 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieber, M. J. A1 - Wilke, M. A1 - Appelt, O. A1 - Oelze, Marcus A1 - Koch-Müller, M. T1 - Melting relations of Ca–Mg carbonates and trace element signature of carbonate melts up to 9 GPa – A proxy for melting of carbonated mantle lithologies N2 - The most profound consequences of the presence of Ca–Mg carbonates (CaCO3–MgCO3) in the Earth’s upper mantle may be to lower the melting temperatures of the mantle and control the melt composition. Low-degree partial melting of a carbonate-bearing mantle produces CO2-rich, silica-poor melts compositionally imposed by the melting relations of carbonates. Thus, understanding the melting relations in the CaCO3–MgCO3 system facilitates the interpretation of natural carbonate-bearing silicate systems. We report the melting relations of the CaCO3–MgCO3 system and the partition coefficient of trace elements between carbonates and carbonate melt from experiments at high pressure (6 and 9 GPa) and temperature (1300–1800 ◦C) using a rocking multi-anvil press. In the absence of water, Ca–Mg carbonates are stable along geothermal gradients typical of subducting slabs. Ca–Mg carbonates (∼ Mg0.1–0.9Ca0.9–0.1CO3) partially melt beneath mid-ocean ridges and in plume settings. Ca–Mg carbonates melt incongruently, forming periclase crystals and carbonate melt between 4 and 9 GPa. Furthermore, we show that the rare earth element (REE) signature of Group-I kimberlites, namely strong REE fractionation and depletion of heavy REE relative to the primitive mantle, is resembled by carbonate melt in equilibrium with Ca-bearing magnesite and periclase at 6 and 9 GPa. This suggests that the dolomite–magnesite join of the CaCO3–MgCO3 system might be useful to approximate the REE signature of carbonate-rich melts parental to kimberlites. KW - High pressure experiments KW - Laser Ablation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561197 DO - https://doi.org/10.5194/ejm-34-411-2022 SN - 0935-1221 VL - 34 IS - 5 SP - 411 EP - 424 PB - Copernicus Publications CY - Göttingen AN - OPUS4-56119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heuser, Lina A1 - Nofz, Marianne A1 - Müller, Ralf A1 - Deubener, J. T1 - Silver dissolution and precipitation in an Na2O–ZnO–B2O3 metallization paste glass N2 - Thermally stimulated interactions between silver and glass, that is, silver dissolution as Ag+ and precipitation as Ag0 were studied in two glass series of molar target composition xAg2O–(19 − x)Na2O–28ZnO–53B2O3 with x = 0, 0.1, 0.5, 5 and (19Na2O–28ZnO–53B2O3)+yAg2O with y = 0.01, 0.05. These act as model for low-melting borate glasses being part of metallization pastes. The occurrence of metallic silver precipitates in melt-quenched glass ingots demonstrated that silver dissolved only in traces (< 0.01 mol%) in the glasses. The dissolved silver was detected by means of Raman spectroscopy and energy-dispersive X-ray spectroscopy. Increasing x in the batch could not lead to a significant increase of the silver ion fraction in the glass as possible in binary silver borate glasses. In situ observation of heated AgNO3 mixed with the base glass frit in a hot stage microscope showed that Ag0 precipitation occurs already at the solid state. At higher temperatures, small droplets of liquid silver were found to move freely within the melt, whereas coalescence caused a stepwise increase of their size. These results contribute to the understanding of formation of silver precipitates in metallization pastes described in the literature. KW - Silver metallization paste KW - Batch reactions KW - Borate KW - Glass forming melts KW - Glass manufacturing KW - Raman spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559433 DO - https://doi.org/10.1111/ijag.16613 SN - 2041-1286 SP - 1 EP - 11 PB - Wiley Online Library AN - OPUS4-55943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henning, L. M. A1 - Müller, J. T. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Schmidt, J. A1 - Bekheet, M. F. A1 - Gurlo, A. A1 - Simon, U. T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3 ), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling. KW - SAXS KW - Hierarchically porous KW - Silica KW - Water filtration PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928 DO - https://doi.org/10.1039/D2NA00368F SN - 2516-0230 SP - 1 EP - 17 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-55592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -