Bulk acoustic wave propagation characteristics in degenerately n-doped Si

2012 ◽  
Author(s):  
Tuomas Pensala ◽  
Mika Prunnila ◽  
Antti Jaakkola
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Bulk Acoustic Wave ◽  
Propagation Characteristics ◽  
Acoustic Wave Propagation

Influence of Moisture of Wheat on Acoustic Wave Propagation Characteristics

2020 ◽  
Vol 63 (5) ◽  
pp. 1315-1326
Author(s):  
Chi Zhang ◽  
Aini Dai ◽  
Haiying Yang ◽  
Zidan Wu ◽  
Xiaoguang Zhou ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Moisture Content ◽  
Acoustic Wave ◽  
Attenuation Coefficient ◽  
Wave Velocity ◽  
Propagation Constant ◽  
Pso Algorithm ◽  
Average Radius ◽  
Propagation Characteristics ◽  
Acoustic Wave Propagation

HighlightsA novel measuring device was developed for the propagation constant of acoustic waves in grain.Increase in moisture of wheat from 1.1% to 7.8% (wet basis) decreased the wave velocity and increased the attenuation coefficient.Increase in moisture of wheat from 7.8% to 21.2% increased the wave velocity and decreased the attenuation coefficient.Using the Johnson-Champoux-Allard (JCA) model and particle swarm optimization (PSO) algorithm, the influence of moisture on the pore structure in wheat was characterized.Abstract. Acoustic methods have been widely used for the measurement of grain moisture content and temperature as well as for detecting the presence of insects in grain. Therefore, this study was conducted to understand the influence of wheat moisture content on acoustic wave propagation characteristics. A novel device was developed for measuring the acoustic wave propagation constant. The propagation constants of 12 samples of wheat were measured, with each sample having a different moisture content in the range from 1.1% to 21.2% (wet basis). The results showed that the acoustic wave velocity decreased slightly with an increase in moisture from 1.1% to 7.8%, while the attenuation coefficient increased slightly. When the moisture increased from 7.8% to 21.2%, the velocity increased gradually, while the attenuation coefficient decreased. A quadratic equation described the results well. In addition, a Johnson-Champoux-Allard (JCA) model was adopted to study the influence of moisture on the pore structure of wheat samples. With the increase in moisture from 1.1% to 21.2%, the average radius of interconnection between two adjacent pores decreased from 0.275 to 0.262 mm at moisture below 7.8% and then increased to 0.304 mm, and the average radius of the pores decreased from 0.773 to 0.481 mm at moisture below 7.8% and then increased to 1.2 mm. Keywords: Acoustic standing wave tube, JCA model, Moisture content, Propagation constant, PSO algorithm, Wheat.

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