Title :
Measurement and calculation of powdered mixture permittivities
Author :
Nelson, Stuart O.
Author_Institution :
Richard B. Russell Agric. Res. Center, U.S. Dept. of Agric., Athens, GA, USA
fDate :
10/1/2001 12:00:00 AM
Abstract :
The permittivities of pulverized samples of coal and limestone were measured over a range of bulk densities at 11.7 GHz and 20°C. The measured values were used, along with particle densities, determined by pycnometer measurements, and the Landau & Lifshitz, Looyenga (LLL) dielectric mixture equation to determine the solid material permittivities. Subsequently, similar measurements were taken on a 35%-65% coal-limestone mixture, and the LLL equation and the complex refractive index (CRI) dielectric mixture equation were used to calculate the permittivities of powdered coal, limestone, and the 35%-65% mixture at various bulk densities. Results compared to the measured permittivities showed that the LLL equation provided much better estimates than the CRI equation, with errors of 0.15% in predicting the dielectric constants of powdered coal, 1.4% in predicting the dielectric constants of powdered limestone, and 0.5% in predicting the dielectric constants of the coal-limestone mixture
Keywords :
coal; density measurement; microwave measurement; mixtures; permittivity; permittivity measurement; powders; pulverised fuels; 11.7 GHz; 20 C; 20°C; coal-limestone mixture; complex refractive index; dielectric mixture equation; limestone; permittivity measurements; powdered coal; pycnometer measurements; solid material permittivities; Density measurement; Dielectric constant; Dielectric loss measurement; Dielectric materials; Dielectric measurements; Equations; Microwave measurements; Particle measurements; Permittivity measurement; Solids;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on