TY - CONF A1 - Howard-Reed, C. A1 - Liu, Z. A1 - Cox, S. A1 - Little, J. A1 - Horn, Wolfgang A1 - Wilke, Olaf A1 - Wiegner, Katharina A1 - Persily, A. T1 - Inter-laboratory study approach to validate the performance of a prototype reference material for product emissions testing N2 - Product emissions chamber testing involves a complex protocol with several sources of measurement uncertainty (ASTM, 2010; ISO, 2006). Despite the potential for significant variability in measurement results within and among laboratories, there is no Standard method available to assess the accuracy of emissions chamber test results. Recently, Germany’s Federal Institute for Materials Research and Testing (BAM) started a program to evaluate the performance of laboratories testing for the AgBB (German Committee for Health-related Evaluation of Building Products) labelling scheme (Wilke et al., 2009). Test method validation was conducted through interlaboratory studies (ILS) with over 30 participants. Simultaneously, the National Institute of Standards and Technology (NIST) and Virginia Tech (VT) started a program to develop a series of reference materials that mimic real building products, can be tested in typical emissions chambers, and have independently known emission rates (Cox et al., 2010). BAM, NIST and VT subsequently joined forces to conduct a series of inter-laboratory studies using the prototype reference material. A pilot ILS was conducted with BAM and NIST followed by an expanded ILS with several participating countries. Results from these interlaboratory studies have the potential to define an internationally-accepted Standard approach to validate results from product emissions tests. T2 - Indoor Air 2011, 12th International conference on indoor air quality and climate CY - Austin, TX, USA DA - 05.06.2011 KW - Test method validation KW - Volatile organic compounds KW - Product certification PY - 2011 IS - Paper 768 SP - 1 EP - 2 AN - OPUS4-23883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cheng, Z. A1 - Meng, M. A1 - Qiao, X. A1 - Liu, Y. A1 - Resch-Genger, Ute A1 - Ou, J. T1 - The synthesis of Er3+/Yb3+/K+ triple-doped NaYF4 phosphors and its high sensitivity optical thermometers at low power N2 - Optical Thermometry is popular among researchers because of its non-contact, high sensitivity, and fast measurement properties. In the present experiment, Er3+/Yb3+/K+ co-doped NaYF4 nanoparticles with different K+ concentrations were synthesized by solvothermal method, and the samples showed bright upconversion green emission under the excitation of a 980 nm laser. The powder X-ray diffractometer and transmission electron microscope were used to characterize the crystal structure and its surface morphology, respectively. The spectral characteristics of nanoparticles with K+ doping concentration from 10% to 30% (Molar ratio) were investigated by fluorescence spectroscopy, and it was observed that the fluorescence intensity reached the maximum at the K+ concentration of 20%, after which the intensity weakened when the K+ content continued to increase. According to the dependence between the luminescence intensity of the sample and the laser power density and fluorescence lifetime, the intrinsic mechanism was carefully investigated. Temperature-dependent spectra of the samples were recorded in the temperature range of 315–495 K, and the maximum values of absolute sensitivity (Sa) and relative sensitivity (Sr) were measured at 0.0041 K−1 (455 K) and 0.9220%K−1 (315 K). The experimental results show that K+/Er3+/Yb3+ triple-doped NaYF4 green fluorescent nanoparticles (GFNs) have good prospects for applications in display devices, temperature sensing, and other fields. KW - K+ doped KW - Upconversion luminescence KW - Optical temperature sensing KW - Thermal coupling energy level PY - 2023 DO - https://doi.org/10.1016/j.jallcom.2022.168299 VL - 937 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-57106 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 - Liu, Y. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Long, W. A1 - Ou, J. T1 - NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ Upconversion Nanoparticles for Optical Temperature Monitoring and Self-Heating in Photothermal Therapy N2 - The core−shell NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ upconversion nanoparticles were successfully prepared by a solvothermal method, and a layer of mesoporous silica (mSiO2) was successfully coated on the periphery of the core−shell nanoparticles to transform their surface from lipophilic to hydrophilic, further expanding their applications in biological tissues. The physical phase, morphology, structure, and fluorescence properties were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (TEM), Fourier infrared spectroscopy (FT-IR), ζ potential analysis, and fluorescence spectroscopy. It was found that the material has a hexagonal structure with good hydrophilicity and emits intense fluorescence under 980 nm pump laser excitation. The non-contact temperature sensing performance of nanoparticles was evaluated by analyzing the upconversion fluorescence of Tm3+ (1G4 → 3F4 and 3F3 → 3H6) in the temperature range of 284−344 K. The absolute and relative sensitivities were found to be 0.0067 K−1 and 1.08 % K−1, respectively, with high-temperature measurement reliability and good temperature cycling performance. More importantly, its temperature measurement in phosphate-buffered saline (PBS) solution is accurate. In addition, the temperature of the cells can be increased by adjusting the laser power density and laser irradiation time. Therefore, an optical temperature sensing platform was built to realize the application of real-time monitoring of cancer cell temperature and the dual function of photothermal therapy. KW - Sensor KW - Temperature KW - Lanthanide KW - Tag KW - Fluorescence KW - Nanoparticles KW - Synthesis KW - Environment KW - Monitoring KW - Sensing KW - Nano KW - Life sciences KW - Upconversion PY - 2023 DO - https://doi.org/10.1021/acsanm.2c05110 VL - 6 IS - 1 SP - 759 EP - 771 PB - ACS Publications AN - OPUS4-57081 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 - Pei, R. A1 - Petrazoller, J. A1 - Atila, Achraf A1 - Arnoldi, S. A1 - Xiao, L. A1 - Liu, X. A1 - Wang, H. A1 - Korte-Kerzel, S. A1 - Berbenni, S. A1 - Richeton, T. A1 - Guénolé, J. A1 - Xie, Z. A1 - Al-Samman, T. T1 - Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study N2 - Solute segregation at low-angle grain boundaries (LAGBs) critically affects the microstructure and mechanicalproperties of magnesium (Mg) alloys. In modern alloys containing multiple substitutional elements, understanding solute-solute interactions at microstructural defects becomes essential for alloy design. This study investigates the co-segregation mechanisms of calcium (Ca), zinc (Zn), and aluminum (Al) at a LAGB in a dilute Mg-0.23Al-1.00Zn-0.38Ca (AZX010) alloy by combining atomic-scale experimental and modeling techniques.Three-dimensional atom probe tomography (3D-APT) revealed significant segregation of Ca, Zn, and Al at the LAGB, with Ca forming linear segregation patterns along dislocation arrays characteristic of the LAGB. Clustering analysis showed increased Ca–Ca pairs at the boundary, indicating synergistic solute interactions. Atomistic simulations and elastic dipole calculations demonstrated that larger Ca atoms prefer tensile regions around dislocations, while smaller Zn and Al atoms favor compressive areas. These simulations also found that Ca–Ca co-segregation near dislocation cores is energetically more favorable than other solute pairings, explaining the enhanced Ca clustering observed experimentally. Thermodynamic modeling incorporating calculated segregation energies and solute-solute interactions accurately predicted solute concentrations at the LAGB, aligning with experimental data. The findings emphasize the importance of solute interactionsat dislocation cores in Mg alloys, offering insights for improving mechanical performance through targeted alloying and grain boundary engineering. KW - Atomic probe tomography KW - Atomistic simulation KW - Grain boundary KW - Co-segregation KW - Magnesium alloy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655248 DO - https://doi.org/10.1016/j.actamat.2026.121947 SN - 1359-6454 VL - 306 SP - 1 EP - 13 PB - Elsevier Inc. AN - OPUS4-65524 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 -