Comparative Determination of Mass Fractions of Elements with Variable Chalcophile Affinities in Geological Reference Materials with and without HF‐desilicification

2020 ◽  
Vol 44 (3) ◽  
pp. 501-521 ◽  
Author(s):  
Zongqi Zou ◽  
Zaicong Wang ◽  
Huai Cheng ◽  
Tao He ◽  
Yinuo Liu ◽  
...  
2009 ◽  
Vol 92 (2) ◽  
pp. 502-510 ◽  
Author(s):  
David L Anderson

Abstract A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 255 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (<2 min) would be needed to screen foods for Br content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels.


2019 ◽  
Vol 43 (4) ◽  
pp. 663-680 ◽  
Author(s):  
Huai Cheng ◽  
Zaicong Wang ◽  
Kang Chen ◽  
Keqing Zong ◽  
Zongqi Zou ◽  
...  

2018 ◽  
Vol 42 (3) ◽  
pp. 361-377 ◽  
Author(s):  
Maria Kirchenbaur ◽  
Alexander Heuser ◽  
Alessandro Bragagni ◽  
Frank Wombacher

Author(s):  
Louis Edwards Cáceres-Martínez ◽  
Diana Carolina Guío-Pérez ◽  
Sonia Lucía Rincón-Prat

AbstractThe present study explores the relevance of the physical properties of biomass particles on the determination of the minimum fluidization velocity (Umf) of binary mixtures. Fluidization experiments were performed in a cold flow unit with diverse biomasses mixed with sand in different mass fractions. Gas velocity and pressure drop across the bed were used to determine Umf. Different correlations reported in the literature were evaluated on their ability to accurately predict Umf of the mixtures. Results showed satisfactory predictions when appropriately identifying correlations according to the corresponding Geldart groups for the biomass particles. This perspective opens new possibilities toward the generalization of correlation factors and helps in improving the accuracy of the prediction for highly heterogeneous mixtures. The methodology also allows the analysis of mixtures for which the experimental approach is difficult, such as those including char particle, with the only requirement of carefully measuring the physical properties of the particles.


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