TY - JOUR A1 - Grulke, E. A. A1 - Yamamoto, K. A1 - Kumagai, K. A1 - Häusler, Ines A1 - Österle, Werner A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Brown, S. C. A1 - Chan, C. A1 - Zheng, J. A1 - Yamamoto, K. A1 - Yashiki, K. A1 - Song, N. W. A1 - Kim, Y. H. A1 - Stefaniak, A. B. A1 - Schwegler-Berry, D. A1 - Coleman, V. A. A1 - Jämting, Å. K. A1 - Herrmann, J. A1 - Arakawa, T. A1 - Burchett, W. W. A1 - Lambert, J. W. A1 - Stromberg, A. J. T1 - Size and shape distributions of primary crystallites in titania aggregates JF - Advanced Powder Technology N2 - The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions were multi-modal but data visualization plots demonstrated that the Weibull distribution was preferred to the normal distribution. For the equivalent circular diameter size descriptor, measurement uncertainties of the lognormal distribution scale and width parameters were 9.5% and 22%, respectively. For the aspect ratio shape descriptor, the measurement uncertainties of the Weibull distribution scale and width parameters were 7.0% and 26%, respectively. Both measurement uncertainty estimates and data visualizations should be used to analyze size and shape distributions of particles on the nanoscale. KW - Measurement uncertainty KW - Size distribution KW - Shape distribution KW - TEM KW - Titania PY - 2017 DO - https://doi.org/10.1016/j.apt.2017.03.027 SN - 0921-8831 VL - 28 IS - 7 SP - 1647 EP - 1659 PB - Elsevier B.V. AN - OPUS4-40478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiedensohler, A. A1 - Wiesner, A. A1 - Weinhold, K. A1 - Birmili, W. A1 - Herrmann, M. A1 - Merkel, M. A1 - Müller, T. A1 - Pfeifer, S. A1 - Schmidt, A. A1 - Tuch, T. A1 - Velarde, F. A1 - Quincey, P. A1 - Seeger, Stefan A1 - Nowak, A. T1 - Mobility particle size spectrometers: Calibration procedures and measurement uncertainties JF - Aerosol Science and Technology N2 - Mobility particle size spectrometers (MPSS) belong to the essential instruments in aerosol science that determine the particle number size distribution (PNSD)in the submicrometer size range. Following calibration procedures and target uncertainties against standards and reference instruments are suggested for a complete MPSS quality assurance program: a) calibration of the CPC counting efficiency curve (within 5% for the plateau counting efficiency; within 1 nm for the 50% detection efficiency diameter), b) sizing calibration of the MPSS, using a certified polystyrene latex (PSL) particle size standard at 203 nm (within 3%), c) intercomparison of the PNSD of the MPSS (within 10% and 20% of the dN/dlogDP concentration for the particle size range 20 – 200 nm and 200 to 800 nm, respectively), and d) intercomparison of the integral PNC of the MPSS (within 10%). Furthermore, following measurement uncertainties have been investigated: a) PSL particle size standards in the range from 100-500nm match within 1% after sizing calibration at 203 nm. b) Bipolar diffusion chargers based on the radioactive nuclides Kr85, Am241 and Ni63 and a new ionizer based on corona discharge follow the recommended bipolar charge distribution, while soft X-ray-based charges may alter faster than expected. c) The use of a positive high voltage supply show a 10% better performance than a negative one. d) The intercomparison of the integral PNC of an MPSS against the total number concentration is still within the target uncertainty at an ambient pressure of approximately 500 hPa. KW - Measurement uncertainties KW - Mobility particle size spectrometer (MPPS) KW - Condensation particle counter (CPC) KW - Calibration PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425060 DO - https://doi.org/10.1080/02786826.2017.1387229 SN - 1521-7388 VL - 52 IS - 2 SP - 146 EP - 164 PB - Tailor & Francis CY - USA AN - OPUS4-42506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -