TY - JOUR A1 - Lin, R. A1 - Li, X. A1 - Krajnc, A. A1 - Li, Z. A1 - Li, M. A1 - Wang, W. A1 - Zhuang, L. A1 - Smart, S. A1 - Zhu, Z. A1 - Appadoo, D. A1 - Harmer, J. R. A1 - Wang, Z. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Beyer, S. A1 - Wang, L. A1 - Mali, G. A1 - Bennett, T. D. A1 - Chen, V. A1 - Hou, J. T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly KW - Electrodes KW - MOF KW - OER KW - XANES KW - XAS KW - Bimetallic frameworks PY - 2022 DO - https://doi.org/10.1002/anie.202112880 VL - 61 IS - 4 SP - e202112880 PB - Wiley AN - OPUS4-54018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, L. A1 - Darvishi Kamachali, Reza A1 - Li, Z. A1 - Zhang, Z. T1 - Grain boundary energy effect on grain boundary segregation in an equiatomic high-entropy alloy N2 - Grain boundary (GB) Segregation has a substantial effect on the microstructure evolution and properties of polycrystalline alloys. The mechanism of nanoscale segregation at the various GBs in multicomponent alloys is of great challenge to reveal and remains elusive so far. To address this issue, we studied the GB segregation in a representative equiatomic FeMnNiCoCr high-entropy alloy (HEA) aged at 450 °C. By combining transmission Kikuchi diffraction, atom probe tomography analysis and a density-based thermodynamics modeling, we uncover the nanoscale segregation behavior at a series of well-characterized GBs of different characters. No segregation occurs at coherent twin boundaries; only slight nanoscale segregation of Ni takes place at the low-angle GBs and vicinal \Sigma 29b coincidence site lattice GBs. Ni and Mn show cosegregation of high levels at the general high-angle GBs with a strong depletion in Fe, Cr, and Co. Our density-based thermodynamic model reveals that the highly negative energy of mixing Ni and Mn is the main driving force for nanoscale cosegregation to the GBs. This is further assisted by the opposite segregation of Ni and Cr atoms with a positive enthalpy of mixing. It is also found that GBs of higher interfacial energy, possessing lower atomic densities (higher disorder and free volume), show higher segregation levels. By clarifying the origins of GB segregations in the FeMnNiCoCr HEA, the current work provides fundamental ideas on nanoscale segregation at crystal defects in multicomponent alloys. KW - Thermodynamics KW - High-Entropy Alloys KW - Grain Boundary Segregation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508827 DO - https://doi.org/10.1103/PhysRevMaterials.4.053603 VL - 4 IS - 5 SP - 053603 PB - American Physical Society AN - OPUS4-50882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qiu, Yan A1 - Yu, H. A1 - Gornushkin, Igor B. A1 - Li, J. A1 - Wu, Q. A1 - Zhang, Z. A1 - Li, X. T1 - Measurement of trace chromium on structural steel surface from a nuclear power plant using dual-pulse fiber-optic laser-induced breakdown spectroscopy N2 - Remote and on-line measurement of chromium on structural steel surface in nuclear power plants is critical for protection against fluid accelerated corrosion. To improve the insufficient sensitivity of fiber-optic laser-induced breakdown spectroscopy toward trace element detection, a dual-pulse spectral enhancement system is set up. In an iron matrix, for the purpose of improving sensitivity of trace chromium analysis and reducing the self-absorption of iron, the effects of key parameters are investigated. The optimal values of the parameters are found to be: 450 ns inter-pulse delay, 700 ns gate delay, 30 mJ/6 mJ pulse energy ratio, and 19.8 mm lens-to-sample distance (corresponding to a 799 μm laser focused spot size). Compared to the single-pulse system, the shot number of dual-pulse ablation is limited for reducing surface damage. After the optimization of the dual-pulse system, the signal-to-noise ratio of the trace chromium emission line has been improved by 3.5 times in comparison with the single-pulse system, and the self-absorption coefficient of matrix iron has been significantly reduced with self-reversal eliminated. The number of detectable lines for trace elements has more than doubled thus increasing the input for spectral calibration without significantly increasing the ablation mass. Three calibration methods including internal standardization, partial least squares regression and random forest regression are employed to determine the chromium and manganese concentrations in standard samples of low alloy steel, and the limit of detection is respectively calculated as 36 and 515 ppm. The leave-one-out cross validation method is utilized to evaluate the accuracy of chromium quantification, and the concentration mapping of chromium is performed on the surface of a steel sample (16MND5) with a relative error of 0.02 wt.% KW - Fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) KW - Dual-pulse KW - Parameter optimization KW - Spectral enhancement KW - Self-absorption coefficient KW - Concentration mapping PY - 2020 DO - https://doi.org/10.1016/j.apsusc.2020.147497 SN - 0169-4332 VL - 533 IS - 147497 SP - 1 EP - 29 PB - Elsevier CY - Amsterdam AN - OPUS4-51143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zare Pakzad, S. A1 - Nasr Esfahani, M. A1 - Tasdemir, Z. A1 - Wollschläger, Nicole A1 - Li, T. A1 - Li, X. A1 - Yilmaz, M. A1 - Leblebici, Y. A1 - Erdem Alaca, B. T1 - Nanomechanical Modeling of the Bending Response of Silicon Nanowires N2 - Understanding the mechanical behavior of silicon nanowires is essential for the implementation of advanced nanoscale devices. Although bending tests are predominantly used for this purpose, their findings should be properly interpreted through modeling. Various modeling approaches tend to ignore parts of the effective parameter set involved in the rather complex bending response. This oversimplification is the main reason behind the spread of the modulus of elasticity and strength data in the literature. Addressing this challenge, a surface-based nanomechanical model is introduced in this study. The proposed model considers two important factors that have so far remained neglected despite their significance: (i) intrinsic stresses composed of the initial residual stress and surface-induced residual stress and (ii) anisotropic implementation of surface stress and elasticity. The modeling study is consolidated with molecular dynamics-based study of the native oxide surface through reactive force fields and a series of nanoscale characterization work through in situ threepoint bending test and Raman spectroscopy. The treatment of the test data through a series of models with increasing complexity demonstrates a spread of 85 GPa for the modulus of elasticity and points to the origins of ambiguity regarding silicon nanowire properties, which are some of the most commonly employed nanoscale building blocks. A similar conclusion is reached for strength with variations of up to 3 GPa estimated by the aforementioned nanomechanical models. Precise consideration of the nanowire surface state is thus critical to comprehending the mechanical behavior of silicon nanowires accurately. Overall, this study highlights the need for a multiscale theoretical framework to fully understand the size-dependent mechanical behavior of silicon nanowires, with fortifying effects on the design and reliability assessment of future nanoelectromechanical systems. KW - Silicon nanowires KW - Native oxide KW - Surface stress KW - Surface elasticity KW - Mechanical behavior PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581676 DO - https://doi.org/10.1021/acsanm.3c02077 SP - 1 EP - 14 PB - ACS Publications AN - OPUS4-58167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nasr Esfahani, M. A1 - Zare Pakzad, S. A1 - Li, T. A1 - Li, X. A1 - Tasdemir, Z. A1 - Wollschläger, Nicole A1 - Leblebici, Y. A1 - Erdem Alaca, B. T1 - Effect of Native Oxide on Stress in Silicon Nanowires: Implications for Nanoelectromechanical Systems N2 - Understanding the origins of intrinsic stress in Si nanowires (NWs) is crucial for their successful utilization as transducer building blocks in next-generation, miniaturized sensors based on anoelectromechanical systems (NEMS). With their small size leading to ultrahigh-resonance frequencies and extreme surface-to-volume ratios, silicon NWs raise new opportunities regarding sensitivity, precision, and speed in both physical and biochemical sensing. With silicon optoelectromechanical properties strongly dependent on the level of NW intrinsic stress, various studies have been devoted to the measurement of such stresses generated, for example, as a result of harsh fabrication processes. However, due to enormous NW surface area, even the native oxide that is conventionally considered as a benign surface condition can cause significant stresses. To address this issue, a combination of nanomechanical characterization and atomistic simulation approaches is developed. Relying only on low-temperature processes, the fabrication approach yields monolithic NWs with optimum boundary conditions, where NWs and support architecture are etched within the same silicon crystal. Resulting NWs are characterized by transmission electron microscopy and micro-Raman spectroscopy. The interpretation of results is carried out through molecular dynamics simulations with ReaxFF potential facilitating the incorporation of humidity and temperature, thereby providing a close replica of the actual oxidation environment - in contrast to previous dry oxidation or self-limiting thermal oxidation studies. As a result, consensus on significant intrinsic tensile stresses on the order of 100 MPa to 1 GPa was achieved as a function of NW critical dimension and aspect ratio. The understanding developed herein regarding the role of native oxide played in the generation of NW intrinsic stresses is important for the design and development of silicon-based NEMS. KW - Nanoelectromechanical systems (NEMS) KW - Silicon nanowires KW - Native oxide KW - Intrinsic stress KW - Raman spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560471 DO - https://doi.org/10.1021/acsanm.2c02983 SN - 2574-0970 VL - 5 SP - 13276 EP - 13285 PB - ACS Publ. CY - Washington, DC AN - OPUS4-56047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Titirici, M. A1 - Baird, S. G. A1 - Sparks, T. D. A1 - Yang, S. M. A1 - Brandt-Talbot, A. A1 - Hosseinaei, O. A1 - Harper, D. P. A1 - Parker, R. M. A1 - Vignolini, S. A1 - Berglund, L. A. A1 - Li, Y. A1 - Gao, H.-L. A1 - Mao, L.-B. A1 - Yu, S.-H. A1 - Díez, N. A1 - Ferrero, G. A. A1 - Sevilla, M. A1 - Szilágyi, P. Á. A1 - Stubbs, C. J. A1 - Worch, J. C. A1 - Huang, Y. A1 - Luscombe, C. K. A1 - Lee, K.-Y. A1 - Luo, H. A1 - Platts, M. J. A1 - Tiwari, D. A1 - Kovalevskiy, D. A1 - Fermin, D. J. A1 - Au, H. A1 - Alptekin, H. A1 - Crespo-Ribadeneyra, M. A1 - Ting, V. P. A1 - Fellinger, Tim-Patrick A1 - Barrio, J. A1 - Westhead, O. A1 - Roy, C. A1 - Stephens, I. E. L. A1 - Nicolae, S. A. A1 - Sarma, S. C. A1 - Oates, R. P. A1 - Wang, C.-G. A1 - Li, Z. A1 - Loh, X. J. A1 - Myers, R. J. A1 - Heeren, N. A1 - Grégoire, A. A1 - Périssé, C. A1 - Zhao, X. A1 - Vodovotz, Y. A1 - Earley, B. A1 - Finnveden, G. A1 - Björklund, A. A1 - Harper, G. D. J. A1 - Walton, A. A1 - Anderson, P. A. T1 - The sustainable materials roadmap N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability. KW - Electrochemistry KW - Fe-N-C catalysts KW - Fuel cells KW - Catalysis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126 DO - https://doi.org/10.1088/2515-7639/ac4ee5 SN - 2515-7639 VL - 5 IS - 3 SP - 1 EP - 98 PB - IOP Publishing CY - Bristol AN - OPUS4-55012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Li, Z. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Long, W. A1 - Ou, Jun T1 - Preparation of NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles and application of their fluorescence temperature sensing properties N2 - The NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles were successfully prepared by the solvothermal method, and the samples were pure hexagonal phase with good crystallinity and homogeneous size, asevidenced by XRD and TEM analysis. The FT-IR analysis shows that β-CD is successfully encapsulated on the surface of NaYF4: Yb3+/Tm3+@NaYF4 nanoparticles. The fluorescence intensity 3and lifetime were significantly increased after coating the inert layer on the surface of core nanoparticles. After further surface modification of β-CD, the fluorescence intensity and fluorescence lifetime were reduced, but the overall fluorescence was stronger. Temperature measurements using the fluorescence intensity ratio technique were found to have relatively low reliability and absolute sensitivity for temperature measurements using thermally coupled energy levels. However, the reliability of temperature measurements using non-thermally coupled energy levels is significantly higher and the absolute sensitivity is much higher than for measurements at thermally coupled levels. Since the maximum absolute sensitivity, maximum relative sensitivity and minimum temperature resolution are determined to be 0.1179 K-1, 2.19 %K􀀀 1 and 0.00019 K, respectively, NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles are expected to be widely used in the biomedical field due to their feasibility, reliability, non-toxicity and harmlessness. KW - Upconversion KW - Surface modification KW - Fluorescence intensity ratio KW - Thermally coupled levels KW - Non-thermally coupled levels PY - 2023 DO - https://doi.org/10.1016/j.optmat.2022.113389 SN - 0925-3467 VL - 136 SP - 1 EP - 11 PB - Elsevier B.V. AN - OPUS4-57105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, Y.-H. A1 - Descalzo López, Ana Belén A1 - Sgen, Z. A1 - Röhr, Holger A1 - Liu, Q. A1 - Wang, Y.-W. A1 - Spieles, Monika A1 - Li, Y.-Z. A1 - Rurack, Knut A1 - You, X.-Z. T1 - Mono- and Di(dimethylamino)styryl-Substituted Borondipyrromethene and Borondiindomethene Dyes with Intense Near-Infrared Fluorescence N2 - Four novel borondipyrromethene (BDP) and -diindomethene (BDI) dyes with one or two (dimethylamino)styryl extensions at the chromophore were synthesized and spectroscopically investigated. An X-ray crystal structure shows that the extended auxochrome is virtually planar. All dyes thus display intense red/near infrared (NIR) absorption and emission. The (dimethylamino)styryl group induces a charge-transfer character that entails bright solvatochromic fluorescence, which is only quenched with increasing solvent polarity according to the energy-gap law. The dye with an additional dimethylanilino group at the meso position of BDP shows a remarkable switching of lipophilicity by protonation. Two dyes with an 8-hydroxyquinoline ligand at the meso position display quenched emission in the presence of Hg2+ or Al3+ owing to electron transfer from the excited BDP to the complexed receptor. The BDI dye presents a pH indicator with bright fluorescence and extremely low fluorescence anisotropy. KW - Borondipyrromethene KW - Dyes KW - Fluorescence KW - Indicators KW - Protonation PY - 2006 DO - https://doi.org/10.1002/asia.200600042 SN - 1861-4728 SN - 1861-471X VL - 1 IS - 1-2 SP - 176 EP - 187 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.-H. A1 - Xu, Z.-M. A1 - Liu, M.-Y. A1 - Tang, D.-H. A1 - Lu, W. A1 - Li, Z.-H. A1 - Teng, J. A1 - Han, X.-H. A1 - Said, Samir A1 - Rohrmann, R. G. T1 - Estimation of the Lateral Dynamic Displacement of High-Rise Buildings underWind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer N2 - This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions KW - Inclination angle KW - High-rise building KW - Lateral dynamic displacement KW - Remote sensing vibrometer PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506833 DO - https://doi.org/10.3390/rs12071120 VL - 12 IS - 7 SP - 1120 PB - MDPI CY - 4052 Basel, Schweiz AN - OPUS4-50683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Abbasi, M. A1 - Pauw, Brian Richard A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schick, C. A1 - Saalwächter, K. A1 - Schönhals, Andreas T1 - Spatial inhomogeneity, Interfaces and Complex Vitrification Kinetics in a Network Forming Nanocomposite N2 - A detailed calorimetric study on an epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) as the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) as nanofiller. The -NH2 group of taurine can react with DGEBA improving the interaction of the polymer with the filler. The combined X-ray scattering, and electron microscopy data showed that the nanocomposite has a partially exfoliated morphology. Calorimetric studies were performed with conventional DSC, temperature modulated DSC (TMDSC) and fast scanning calorimetry (FSC) in the temperature modulated approach (TMFSC) to investigate the vitrification and molecular mobility in dependence of the filler concentration. First, TMDSC and NMR were used to estimate the amount of the rigid amorphous fraction which consists of immobilized polymer segments at the nanoparticle surface. It was found to be 40 wt% for the highest filler concentration, indicating that the interface dominates the overall macroscopic properties and behavior of the material to a great extent. Second, the relaxation rates of the α-relaxation obtained by TMDSC and TMFSC were compared with the thermal and dielectric relaxation rates measured by static FSC. The investigation revealed that the system shows two distinct α-relaxation processes. Furthermore, also two separate vitrification mechanisms were found for a bulk network-former without geometrical confinement as also confirmed by NMR. This was discussed in terms of the intrinsic spatial heterogeneity on a molecular scale, which becomes more pronounced with increasing nanofiller content. KW - Polymer based Nanocomposites PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523199 DO - https://doi.org/10.1039/d0sm01992e SN - 1744-6848 VL - 17 IS - 10 SP - 2775 EP - 2790 PB - Royal Society of Chemistry AN - OPUS4-52319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jiang, C. A1 - Xie, G. A1 - Wu, Dejian A1 - Yan, T. A1 - Chen, S. A1 - Zhao, P. A1 - Wu, Z. A1 - Li, W. T1 - Experimental investigation on an energy-efficient floor heating system with intelligent control: A case study in Chengdu, China N2 - The space heating system accounts for 20%~50% of building energy consumption, and may lead to energy waste due to unreasonable controls. In this study, an energy-efficient floor heating system with intelligent control was proposed to improve energy efficiency of the system. In order to validate the concept of the proposed intelligent control, an experimental system was designed and constructed in Chengdu, China. Temperature, control cycle and energy consumption were then studied under different control strategies. The result shows that a larger flow rate of supply water will result in a longer control cycle and a lower control frequency, i.e., the average control cycle at 7 L min−1 is 1.7 h during the test day, while it is 1.5 h at 5 L min−1. Moreover, adopting water with a higher temperature and flow rate could achieve a higher efficiency of the system. The energy consumptions in case 1 (5 L min−1, 50 °C), case 2 (5 L min−1, 55 °C), case 5 (7 L min−1, 55 °C) and case 6 (7 L min−1, 60 °C) are 4746 kJ, 3534 kJ, 3093 kJ and 3028 kJ, respectively. Based on the experimental data, the supply water temperature is suggested to set lower than 60 °C considering human comfort. KW - Floor heating KW - Intelligent control KW - Experimental KW - Energy consumption KW - Control strategy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550522 DO - https://doi.org/10.1016/j.csite.2021.101094 SN - 2214-157X VL - 26 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-55052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Song, Z. A1 - He, T. A1 - Li, M. A1 - Wu, Dejian A1 - You, F. T1 - Self-sustaining smoldering as a novel disposal approach for food waste with high moisture content N2 - This work aims to explore the self-sustaining smoldering treatment (SSST) for the destruction of food waste. The food waste used in this work mainly consists of cereal, vegetable, and meat. To examine the processing procedures and parameters, three experimental groups (raw food waste, food-waste paste and food-waste paste blended with anthracite) and five variables (moisture content, sand size, sand-to-food waste ratio, air flow and food waste-to-coal ratio) were extensively investigated. Results show that raw food waste with 40% moisture content can be disposed by SSST with the mass destruction ratio over 90%. However, the robustness of SSST for raw food waste is constrained by the heterogeneous issue due to a variety of components and sizes of food waste. This issue is addressed through stir pre-processing of raw food waste as food-waste paste. The robustness of SSST for food waste is significantly further enhanced only if a slight mass fraction of anthracite (<20% of raw food waste) is supplemented. This provides an alternative solution for employing SSST for raw food waste with very high moisture content. KW - Food waste KW - Waste disposal KW - Smoldering combustion KW - Self-sustaining propagation PY - 2021 DO - https://doi.org/10.1016/j.fuproc.2021.107144 SN - 0078-3820 VL - 228 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-55053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Z. A1 - Raab, A. A1 - Kolmangadi, Mohamed Aejaz A1 - Busch, M. A1 - Grunwald, M. A1 - Demel, F. A1 - Bertram, F. A1 - Kityk, A. V. A1 - Schönhals, Andreas A1 - Laschat, S. A1 - Huber, P. T1 - Self-Assembly of Ionic Superdiscs in Nanopores N2 - Discotic ionic liquid crystals (DILCs) consist of self-assembled superdiscs of cations and anions that spontaneously stack in linear columns with high one-dimensional ionic and electronic charge mobility, making them prominent model systems for functional soft matter. Compared to classical nonionic discotic liquid crystals, many liquid crystalline structures with a combination of electronic and ionic conductivity have been reported, which are of interest for separation membranes, artificial ion/proton conducting membranes, and optoelectronics. Unfortunately, a homogeneous alignment of the DILCs on the macroscale is often not achievable, which significantly limits the applicability of DILCs. Infiltration into nanoporous solid scaffolds can, in principle, overcome this drawback. However, due to the experimental challenges to scrutinize liquid crystalline order in extreme spatial confinement, little is known about the structures of DILCs in nanopores. Here, we present temperaturedependent high-resolution optical birefringence measurement and 3D reciprocal space mapping based on synchrotron X-ray scattering to investigate the thermotropic phase behavior of dopamine-based ionic liquid crystals confined in cylindrical channels of 180 nm diameter in macroscopic anodic aluminum oxide membranes. As a function of the membranes’ hydrophilicity and thus the molecular anchoring to the pore walls (edge-on or face-on) and the variation of the hydrophilic−hydrophobic balance between the aromatic cores and the alkyl side chain motifs of the superdiscs by tailored chemical synthesis, we find a particularly rich phase behavior, which is not present in the bulk state. It is governed by a complex interplay of liquid crystalline elastic energies (bending and splay deformations), polar interactions, and pure geometric confinement and includes textural transitions between radial and axial alignment of the columns with respect to the long nanochannel axis. Furthermore, confinement-induced continuous order formation is observed in contrast to discontinuous first-order phase transitions, which can be quantitatively described by Landau-de Gennes free energy models for liquid crystalline order transitions in confinement. Our observations suggest that the infiltration of DILCs into nanoporous solids allows tailoring their nanoscale texture and ion channel formation and thus their electrical and optical functionalities over an even wider range than in the bulk state in a homogeneous manner on the centimeter scale as controlled by the monolithic nanoporous scaffolds. KW - Ionic Liquid Crystals KW - Nanopropous materials KW - Landau de-Gennes analysis KW - X-ray scattering KW - Optical birefringence PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600797 DO - https://doi.org/10.1021/acsnano.4c01062 SN - 1936-0851 VL - 18 IS - 22 SP - 14414 EP - 14426 PB - ACS AN - OPUS4-60079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, W. A1 - Said, Samir A1 - Rohrmann, R. A1 - Teng, J. A1 - Li, Z. A1 - Lu, W. A1 - Cunha, A. T1 - Operational modal analysis and continuous dynamic monitoring of structures N2 - This paper addresses operational modal analysis (OMA) and continuous dynamic monitoring (CDM) of two bridges. One of them is installed with Tuned Mass Dampers (TMDs) while another one is a normal bridge. Two ambient vibration tests were performed on these two bridges respectively. It is observed that not only installation of TMDs but also environmental factors influence the variations of structural frequencies, which may mask the subtle change induced by small structural changes. As a result, continuous dynamic monitoring systems were implemented on these two bridges, in order to evaluate efficiency of the TMD system, remove the environmental effects and build reliable damage indices that are only sensitive to structural changes. The results of CDM of these two bridges during several years are presented. Software systems developed for OMA and CDM are also introduced. T2 - 14th International Symposium on Structural Engineering (ISSE-14) CY - Beijing, Peoples Republic of China DA - 12.10.2016 KW - Structure KW - Operational modal analysis KW - Continuous dynamic monitoring PY - 2016 SN - 978-7-03-050125-7 VL - 2016 SP - 366 EP - 372 PB - Science Press Beijing AN - OPUS4-38876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Z. A1 - Gao, S. A1 - Brand, U. A1 - Hiller, K. A1 - Wollschläger, Nicole A1 - Pohlenz, F. T1 - Note: Nanomechanical characterization of soft materials using a micro-machined nanoforce transducer with an FIB-made pyramidal tip N2 - The quantitative nanomechanical characterization of soft materials using the nanoindentation technique requires further improvements in the performances of instruments, including their force Resolution in particular. A micro-machined silicon nanoforce transducer based upon electrostatic comb drives featuring the force and depth resolutions down to 1 nN and 0.2 nm, respectively, is described. At the end of theMEMStransducer’s main shaft, a pyramidal tip is fabricated using a focused ion beam facility. A proof-of-principle setup with this MEMS nanoindenter has been established to measure the mechanical properties of soft polydimethylsiloxane. First measurement results demonstrate that the prototype measurement system is able to quantitatively characterize soft materials with elastic moduli down to a few MPa. KW - MEMS KW - Indentation KW - Soft material PY - 2017 DO - https://doi.org/10.1063/1.4977474 SN - 0034-6748 SN - 1089-7623 VL - 88 IS - 3 SP - 036104-1 EP - 036104-3 PB - AIP Publishing AN - OPUS4-39313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adwani, D. A1 - Pipintakos, G. A1 - Mirwald, J. A1 - Wang, Y. A1 - Hajj, R. A1 - Guo, M. A1 - Liang, M. A1 - Jing, R. A1 - Varveri, A. A1 - Zhang, Y. A1 - Pei, K. A1 - Xu, X. A1 - Leng, Z. A1 - Li, D. A1 - Villamil, W. A1 - Caro, S. A1 - Chailleux, E. A1 - Cantot, J. A1 - Weigel, Sandra A1 - Škulteckė, J. A1 - Tarsi, G. A1 - Margaritis, A. A1 - Wang, H. A1 - Hu, Y. A1 - Airey, G. A1 - Sreeram, A. A1 - Bhasin, A. T1 - Examining the efficacy of promising antioxidants to mitigate asphalt binder oxidation: Insights from a worldwide interlaboratory investigation N2 - Oxidative aging induces significant stiffening of asphalt binders that leads to a pronounced reduction in the overall durability of asphalt pavements. The strategic implementation of antioxidant additives provides a potential solution to alleviate this issue. This work presents results from the second phase of the global consortium for antioxidants research aimed at investigating the effectiveness of potential antioxidants in increasing the durability of asphalt binders. Sixteen laboratories around the world participated in this effort and a total of 28 binders from diverse geographical regions were tested. Two promising antioxidants, namely zinc diethyldithiocarbamate (ZDC) and kraft lignin were evaluated in this phase and blended with the binders at specific proportions. Subsequently, a comprehensive investigation was conducted to assess rheological characteristics and chemical properties of the various blends, utilising Dynamic Shear Rheometer (DSR) measurements and Fourier Transform Infrared (FTIR) Spectroscopy. The findings indicate that additives such as ZDC hold considerable promise as an effective antioxidant, particularly when considering a wide diversity of binders. In general, its incorporation does not compromise the rutting performance of the binders and significantly improves fatigue performance. Therefore, research efforts should be focused on exploring additional facets to assess its practical applicability in field. KW - Asphalt oxidation KW - Binder aging KW - Antioxidant additives KW - Binder rheology KW - Binder chemistry KW - Bitumen und bitumenhaltige Bindemittel KW - FTIR-Spektroskopie KW - Anwendungsmöglichkeiten KW - Vergleichsuntersuchung KW - Arbeitsanleitung KW - Präzision PY - 2024 DO - https://doi.org/10.1080/10298436.2024.2332363 SN - 1477-268X VL - 25 IS - 1 SP - 1 EP - 15 PB - Taylor & Francis CY - London AN - OPUS4-59957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Omar, Hassan A1 - Smales, Glen Jacob A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Calorimetric and Dielectric Investigations of Epoxy-Based Nanocomposites with Halloysite Nanotubes as Nanofillers N2 - Epoxy nanocomposites are promising materials for industrial applications (i.e., aerospace, marine and automotive industry) due to their extraordinary mechanical and thermal properties. Here, the effect of hollow halloysite nanotubes (HNT) on an epoxy matrix (Ep) was the focus of the study. The structure and molecular mobility of the nanocomposites were investigated using a combination of X-ray scattering, calorimetry (differential (DSC) and fast scanning calorimetry (FSC)) and dielectric spectroscopy. Additionally, the effect of surface modification of HNT (polydopamine (PDA) and Fe(OH)3 nanodots) was considered. For Ep/HNT, the glass transition temperature (Tg) is was de-creased due to a nanoparticle-related decrease of the crosslinking density. For the modified system, Ep/m-HNT, the surface modification resulted in enhanced filler–matrix interactions leading to higher Tg values than the pure epoxy in some cases. For Ep/m-HNT, the amount of interface formed between the nanoparticles and the matrix ranged from 5% to 15%. Through BDS measurements, localized fluctuations were detected as a β- and γ-relaxation, related to rotational fluctuations of phenyl rings and local reorientations of unreacted components. A combination of calorimetry and BDS dielectric spectroscopy revealed a dynamic and structural heterogeneity of the matrix, as confirmed by two glassy dynamics in both systems, related to regions with different crosslinking densities. KW - Rigid amorphous fraction KW - Epoxy nanocomposites KW - Halloysite nanotubes KW - X-ray scattering KW - Differential scanning calorimetry KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526668 DO - https://doi.org/10.3390/polym13101634 VL - 13 IS - 10 SP - 1634 PB - MDPI AN - OPUS4-52666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed A. A1 - Raab, A. R. A1 - Szymoniak, Paulina A1 - Li, Z. A1 - Huber, P. A1 - Laschat, S. A1 - Schönhals, Andreas T1 - Molecular mobility and electrical conductivity of amino acid-based (DOPA) ionic liquid crystals in the bulk state and nanoconfinement N2 - This study explores the molecular mobility, phase behavior, and electrical conductivity of dihydroxyphenylalanine-based ionic liquid crystals (DOPAn, with alkyl side chains n = 12, 14, 16) featuring cyclic guanidiniumchloride headgroups, in both bulk and nanoconfined states. Using broadband dielectric spectroscopy, differential scanning calorimetry, and fast scanning calorimetry, the research uncovers a complex interplay between molecular structure, self-assembly, and molecular mobility. In bulk, DOPAn shows a phase sequence from plastic crystalline to hexagonal columnar and isotropic phases, driven by superdisc formation and columnar organization. Multiple relaxation processes are identified: localized side-chain dynamics (γ-relaxation), ionic headgroup or core motions (α1-relaxation), and cooperative alkyl domain fluctuations (α2-relaxation). Conductivity decreases with increasing side chain length. Under nanoconfinement in anodic aluminum oxide membranes, phase behavior changes: the Colh–Iso transition is suppressed, and a new α3-relaxation appears, linked to dynamics in an adsorbed interfacial layer. DC conductivity drops by up to four orders of magnitude due to confinement effects, altered molecular orientation, and phase transitions—especially the emergence of a nematic-like state in DOPA16. These findings highlight the importance of molecular design, pore geometry, and surface chemistry in tuning ionic liquid crystal properties for advanced applications in nanofluidics, ion transport, and responsive materials. KW - Ionic Liquid Crystals PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639657 DO - https://doi.org/10.1039/d5cp02406d SN - 1463-9084 SP - 1 EP - 17 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Choteau, T. A1 - Daireaux, A. A1 - Stoppacher, N. A1 - Wielgosz, R. A1 - Davies, S. A1 - do Rego, E. A1 - Wollinger, W. A1 - Garrido, B. A1 - Fernandes, J. A1 - Lima, J. A1 - Oliveira, R. A1 - de Sena, R. A1 - Windust, A. A1 - Huang, T. A1 - Dai, X. A1 - Quan, C. A1 - He, H. A1 - Zhang, W. A1 - Wei, C. A1 - Li, N. A1 - Gao, D. A1 - Liu, Z. A1 - Lo, M. A1 - Wong, W. A1 - Pfeifer, Dietmar A1 - Koch, Matthias A1 - Dorgerloh, Ute A1 - Rothe, Robert A1 - Philipp, Rosemarie A1 - Hanari, N. A1 - Rezali, M. A1 - Arzate, C. A1 - Berenice, M. A1 - Caballero, V. A1 - Osuna, M. A1 - Krylov, A. A1 - Kharitonov, S. A1 - Lopushanskaya, E. A1 - Liu, Q. A1 - Lin, T. A1 - Fernandes-Whaley, M. A1 - Quinn, L. A1 - Nhlapo, N. A1 - Prevoo-Franzsen, D. A1 - Archer, M. A1 - Kim, B. A1 - Baek, S. A1 - Lee, S. A1 - Lee, J. A1 - Marbumrung, S. A1 - Kankaew, P. A1 - Chaorenpornpukdee, K. A1 - Chaipet, T. A1 - Shearman, K. A1 - Gören, A. A1 - Gündüz, S. A1 - Yilmaz, H. A1 - Un, I. A1 - Bilsel, G. A1 - Clarkson, C. A1 - Bedner, M. A1 - Camara, J. A1 - Lang, B. A1 - Lippa, K. A1 - Nelson, M. A1 - Toman, B. A1 - Yu, L. T1 - Mass fraction assignment of folic acid in a high purity material - CCQM-K55.d (Folic acid) Final Report N2 - The comparison required the assignment of the mass fraction of folic acid present as the main component in the comparison sample. Performance in the comparison is representative of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molecular weight range 300–500] and high polarity (pKOW < −2). Methods used by the eighteen participating NMIs or DIs were based on a mass balance (summation of impurities) or qNMR approach, or the combination of data obtained using both methods. The qNMR results tended to give slightly lower values for the content of folic acid, albeit with larger associated uncertainties, compared with the results obtained by mass balance procedures. Possible reasons for this divergence are discussed in the report, without reaching a definitive conclusion as to their origin. The comparison demonstrates that for a structurally complex polar organic compound containing a high water content and presenting a number of additional analytical challenges, the assignment of the mass fraction content property value of the main component can reasonably be achieved with an associated relative standard uncertainty in the assigned value of 0.5% KW - CCQM key comparison KW - Purity assessment KW - Folic acid PY - 2018 UR - https://www.bipm.org/utils/common/pdf/final_reports/QM/K55/CCQM-K55.d.pdf DO - https://doi.org/10.1088/0026-1394/55/1A/08013 VL - 55 IS - Technical Supplement, 2018 SP - 08013, 1 EP - 38 PB - Institute of Physics Publishing (IOP) ; Bureau International des Poids et Mesures AN - OPUS4-44999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, C. A1 - Tian, X. A1 - Wang, L. A1 - Liu, Y. A1 - Wirth, Cynthia A1 - Günster, Jens A1 - Li, D. A1 - Jin, Z. T1 - Effect of particle size gradation on the performance of glass-ceramic 3D printing process N2 - Particle size gradation is regarded as an effective method for overcoming the contradicting requirements in three-dimensional printing (3DP). In present work, particle size gradation was optimized to obtain both acceptable flowability of the powder material and high-strength 3D-printed glass-ceramic products. The effect of gradation on the printing process, sintering process and performance of the 3D-printed glass-ceramic products was investigated comprehensively. The glass-ceramic powders with three size ranges were mixed in certain proportions and applied to print parts. The result showed parts printed with powder mixed by 60 wt% 45–100 µm and 40 wt% 0–25 µm particles had satisfactory density of 1.60 g/cm³ and bending strength of 13.8 MPa. The flowability decreased with an increasing proportion of fine particles. Part density was determined by the powder bulk density in the powder bed as well as the shrinkage during sintering while strength of part was found to be dependent on the sintering degree. KW - Flowability KW - Glass-ceramic KW - Particle size gradation KW - Three-dimensional printing KW - Mechanical properties PY - 2017 DO - https://doi.org/10.1016/j.ceramint.2016.09.197 SN - 0272-8842 VL - 43 IS - 1 SP - 578 EP - 584 PB - Elsevier AN - OPUS4-39783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Khare, V. A1 - Li, Z. A1 - Mantion, Alexandre A1 - Ayi, A. A. A1 - Sonkaria, S. A1 - Voelkl, A. A1 - Thünemann, Andreas A1 - Taubert, A. T1 - Strong anion effects on gold nanoparticle formation in ionic liquids N2 - Ionic liquids (ILs) have attracted tremendous interest in the recent past for their potential in many chemical fields. The current report explores the effects of a set of ILs based on the 1-ethyl-3-methyl-imidazolium cation and different anions on the formation of gold nanoparticles. X-Ray diffraction finds face-centered cubic gold in all cases, but transmission electron microscopy (TEM) shows that there are distinct differences in particle formation and stabilization with the ethyl sulfate (ES), trifluoromethanesulfonate (TfO) and methanesulfonate (MS) anions. With the MS anion, nanoparticles with diameters between 5 and 7 nm form, which increasingly aggregate at higher reaction temperatures. With TfO, also small 5 to 7 nm particles form, but only at low temperatures. Above ca. 160 °C, large, ill-defined and aggregated particles form. With ES, polydisperse samples form at all temperatures except 160 °C. In this case the nanoparticles appear often surrounded by an IL film, which appears to stabilize individual, ca. 15 to 20 nm particles. Dynamic light scattering and UV/Vis spectroscopy further show that in suspension the particles are, much like seen in the TEM, more strongly aggregated with higher reaction temperatures. In summary, the results suggest that there are very specific IL-gold interactions that are responsible for the formation of gold particles with an IL-specific shape, size, and aggregation behavior. KW - Ionic liquid templating KW - Gold nanoparticle KW - Ionic liquid PY - 2010 DO - https://doi.org/10.1039/b917467b SN - 0959-9428 SN - 1364-5501 VL - 20 SP - 1332 EP - 1339 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-20872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dzugan, J. A1 - Lucon, E. A1 - Koukolikova, M. A1 - Li, Y. A1 - Rzepa, S. A1 - Yasin, M.S. A1 - Shao, S. A1 - Shamsaei, N. A1 - Seifi, M. A1 - Lodeiro, M. A1 - Lefebvre, F. A1 - Mayer, U. A1 - Olbricht, Jürgen A1 - Houska, M. A1 - Mentl, V. A1 - You, Z. T1 - ASTM interlaboratory study on tensile testing of AM deposited and wrought steel using miniature specimens N2 - An interlaboratory study, involving eigth international laboratories and coordinated by COMTES FHT (Czech Republic), was conducted to validate tensile measurements obtained using miniature specimens on additively manufactured (AM) components and artifacts. In addition to AM 316L stainless steel (316L SS), a wrought highstrength steel (34CrNiMo6V, equivalent to AISI 4340) was also used. Based on the results, a precision statement in accordance with ASTM E691 standard practice was developed, intended for inclusion in a proposed annex to the ASTM E8/E8M tension testing method. The primary outcomes of the study highlighted the agreement between yield and tensile strength measured from miniature and standard-sized tensile specimens. Furthermore, most tensile properties exhibited similar standard deviations, offering users insight into the efficacy of miniature specimen applications. KW - 316L stainless steel KW - Additive manufacturing KW - High-strength steel KW - Miniature specimens KW - Tensile tests PY - 2024 DO - https://doi.org/10.1016/j.tafmec.2024.104410 SN - 0167-8442 VL - 131 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-60180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schoenhals, Andreas T1 - Dielectric and flash DSC investigations on an epoxy based nanocomposite system with MgAl layered double hydroxide as nanofiller N2 - Nanocomposites based on MgAL layered double hydroxides (LDH) and an epoxy resin were prepared and investigated by a combination of complementary methods. As epoxy resin Bisphenol A diglycidyl ether (DGEBA) was used with Diethylenetriamine as curing agent. The LDH was modified with taurine, which acts as an additional crosslinking agent due to its amine groups. The epoxy resin was cured in a presence of the nanofiller, which was added to the system in various concentrations. X-ray scattering, by combination of SAXS and WAXS was used to characterize the morphology of the obtained nanocomposites. These investigations show that the filler is distributed in the matrix as small stacks of ca. 10 layers. The molecular dynamics of the system, as probe for structure, was investigated by broadband dielectric spectroscopy. In addition to the - and -relaxation (dynamic glass transition), characteristic for the unfilled materials, a further process was found which was assigned to localized fluctuations of segments physically adsorbed or chemically bonded to the nanoparticles. The dielectric -relaxation is shifted to higher temperatures for the nanocomposites in comparison to the pure material but depends weakly on the content of nanoparticles. Further, for the first time Flash DSC was employed to a thermosetting system to investigate the glass transition behavior of the nanocomposites. The heating rates were converted in to relaxation rates. For low concentrations of the nanofiller the thermal data overlap more or less with that of the pure epoxy. For higher concentrations the thermal data are shifted significantly to higher temperatures. This is discussed in terms the cooperativity approach to the glass transition. KW - Nanocomposites KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2019 DO - https://doi.org/10.1016/j.tca.2019.01.010 SN - 0040-6031 VL - 677 SP - 151 EP - 161 PB - Elsevier AN - OPUS4-48218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gao, S. A1 - Hou, J. A1 - Deng, Z. A1 - Wang, T. A1 - Beyer, Sebastian A1 - de Oliveira Guilherme Buzanich, Ana A1 - Richardson, J. J. A1 - Rawal, A. A1 - Seidel, R. A1 - Zulkifli, M. Y. A1 - Li, W. A1 - Bennett, T. D. A1 - Cheetham, A. K. A1 - Liang, K. T1 - Improving the Acidic Stability of Zeolitic Imidazolate Frameworks by Biofunctional Molecules N2 - Zeolitic imidazolate frameworks (ZIFs) have been widely investigated for their use in separation, gas adsorption, catalysis, and biotechnology. Their practical applications, however, can be hampered by their structural instability in humid acidic conditions. Here, guided by density functional theory calculations, we demonstrate that the acidic stability of two polymorphic ZIFs (i.e., ZIF-8 and ZIF-L) can be enhanced by the incorporation of functional groups on polypeptides or DNA. A range of complementary synchrotron investigations into the local chemical structure and bonding environment suggest that the enhanced acidic stability arises from the newly established coordinative interactions between the Zn centers and the inserted carboxylate (for polypeptides) or phosphate (for DNA) groups, both of which have lower pKas than the imidazolate ligand. With functional biomolecular homologs (i.e., enzymes), we demonstrate a symbiotic stability reinforcement effect, i.e., the encapsulated biomolecules stabilize the ZIF matrix while the ZIF exoskeleton protects the enzyme from denaturation. KW - Zeolitic Imidazolate Frameworks KW - Biofunctional Molecules KW - X-ray Absorption Spectroscopy PY - 2019 DO - https://doi.org/10.1016/j.chempr.2019.03.025 VL - 5 IS - 6 SP - 1597 EP - 1608 PB - Elsevier Inc. AN - OPUS4-48702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cabeza, Sandra A1 - Cawley, P. A1 - Li, Z. A1 - Dixon, S. A1 - Jarvis, R. A1 - Nagy, P. B. T1 - Experimental studies of the magneto-mechanical memory (MMM) technique using permanently installed magnetic sensor arrays N2 - The magneto-mechanical memory (MMM) method, that is often referred to as the metal magnetic memory method, has been reported to be a non-destructive testing technique capable of quantifying stress concentrations and detecting defects in ferromagnetic materials. The underlying mechanism behind MMM has been explained in the literature, but the sensitivity to stress concentration has not been satisfactorily investigated. In this paper, both the normal and tangential components of the stress-induced MMM signal were measured by permanently installed magnetic sensor arrays on specimens made from three grades of L80 alloy steel and 20 other structural steels; tests were also carried out on a pipe made from the 4140-L80 steel. As expected, the stress history affects the MMM signal, but the experimental results show that significant irreversible change of magnetization always occurs only in the first cycle of loading regardless whether the deformation is purely elastic or partially plastic. If the peak stress level is increased at a given point during cycling, the immediately following next cycle acts as a new “first” cycle at that peak stress level and causes additional significant irreversible change of magnetization, but there is no evidence that plastic deformation might build up a cumulative magnetization. The MMM effect is very small in the steel samples tested, indicating that it will not be useful in field applications. In un-notched specimens the irreversible change in magnetization caused a proportional change in the measured external magnetic field on the order of only 5–10 A/m, while in the case of notched specimens the leakage field was on the order of 30–60 A/m. KW - Magneto-mechanical memory KW - Stress concentration KW - Permanently installed sensors KW - Irreversible change KW - Cumulative magnetization PY - 2017 DO - https://doi.org/10.1016/j.ndteint.2017.07.019 SN - 0963-8695 SN - 1879-1174 VL - 92 SP - 136 EP - 148 PB - Elsevier Ltd. AN - OPUS4-42936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raab, A. R. A1 - Grießler, T. R. A1 - Rück, D. A1 - Li, Z. A1 - Zens, A. A1 - Bruckner, J. R. A1 - Huber, P. A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Laschat, S. T1 - Salt complexation drives liquid crystalline selfassembly in crown ether–amino acid hybrids N2 - Crown ether–amino acid hybrids represent a promising class of amphiphilic molecules combining ion recognition with self-assembly capabilities. Despite extensive studies on their binding properties, the influence of inorganic salt complexation on their liquid crystalline behaviour remains underexplored. Here we synthesized amphiphilic [18]-crown-6 derivatives of L-dihydroxyphenylalanine and tetrahydroisoquinoline analogues, systematically investigating the effects of alkyl chain length and salt type on mesophase formation. Complexation with various salts induced liquid crystalline phases, transitioning from smectic A to columnar hexagonal structures as anion size and alkyl chain length increased. Structural analyses and electron density mapping revealed assembly into charged superdiscs forming columnar stacks with tunable ion channels. Broadband dielectric spectroscopy highlighted differences in molecular mobility and conductivity linked to molecular design. These findings establish salt complexation as a key strategy to control self-assembly and ion transport in crown ether–amino acid hybrids, advancing their potential in responsive soft materials and ion-conductive applications. KW - Ionic liquid crystals PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655986 DO - https://doi.org/10.1039/d5tc04129e SP - 1 EP - 18 PB - Royal Society of Chemistry (RSC) AN - OPUS4-65598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.-H A1 - Tang, D.-H. A1 - Wang, M. A1 - Liu, J.-L. A1 - Li, Z.-H. A1 - Lu, W. A1 - Teng, J. A1 - Said, Samir A1 - Rohrmann, R. G. T1 - Resonance Monitoring of a Horizontal Wind Turbine by Strain-Based Automated Operational Modal Analysis N2 - A strain-based automated operational modal analysis algorithm is proposed to track the long-term dynamic behavior of a horizontal wind turbine under operational conditions. This algorithm is firstly validated by a scaled wind turbine model, and then it is applied to the dynamic strain responses recorded from a 5 MW wind turbine system. We observed variations in the fundamental frequency and 1f, 3f excitation frequencies due to the mass imbalance of the blades and aerodynamic excitation by the tower dam or tower wake. Inspection of the Campbell diagram revealed that the adverse resonance phenomenon and Sommerfeld effect causing excessive vibrations of the wind tower. KW - Strain KW - Automated operational modal analysis KW - Resonance KW - Horizontal wind turbine PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503350 DO - https://doi.org/10.3390/en13030579 VL - 13 IS - 3 SP - 579 EP - 584 PB - MDPI CY - Schweiz, Basel AN - OPUS4-50335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deng, C. A1 - Yin, Huajie A1 - Li, R.-M. A1 - Huang, S.-C. A1 - Schartel, Bernhard A1 - Wang, Y.-Z. T1 - Modes of action of a mono-component intumescent flame retardant MAPP in polyethylene-octene elastomer N2 - A mono-component intumescent flame retardant named ethylenediamine-modified ammonium polyphosphate (MAPP) is used in polyethylene-octene elastomer (POE). Insight into the flame-retardant mechanisms of the MAPP is provided from a new perspective. The fire performance of POE/MAPP composites is investigated by oxygen index (OI) and vertical burning (UL-94) tests. POE Composite containing 35 wt% MAPP achieves a V-0 rating, and its OI is 29.3 vol%. The thermogravimetric Analysis (TGA) and Fourier transform infrared spectra (FTIR) confirm that the incorporation of ethylenediamine changes the thermal decomposition of APP, mainly resulting in the formation of char layer with a thermally stable structure. Cone calorimeter analysis revealed the flame-retardant modes of action of MAPP in POE under forced-flaming conditions. Quantitative analysis illustrates that both the residue due to charring and the fuel dilution/flame Inhibition resulting from the release of incombustible products/ phosphorus species decrease the total heat release (fire load) by 20e28%. The residue increases linearly with increasing MAPP content, whereas the reduction in effective heat of combustion levels off. Moreover, the flame-retardant effect resulting from the protective properties of the char is discovered to be the dominant mode of action (up to 85% reduction) with respect to the peak heat release rate, leading to the excellent flame retardancy of POE/MAPP. KW - Ammonium polyphosphate KW - Flame retardant KW - Carbonization KW - Elastomer PY - 2017 DO - https://doi.org/10.1016/j.polymdegradstab.2017.03.006 SN - 0141-3910 SN - 1873-2321 VL - 138 SP - 142 EP - 150 PB - Elsevier AN - OPUS4-39901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -