| Summary: | 碩士 === 中興大學 === 生物產業機電工程學系所 === 95 === The amount of moisture content of brown rice is very important factor to influence its storage quality and storage duration. So far, moisture contents of brown rice are nondestructively determined using electronic methods in many researches. Although the electronic method is very closely to a real time method, but is still not good for online measurement. In this study, a sensing unit with two copper rods is used to intrude and contact brown rice directly to measuring the moisture content according to the concept of bio-electricity. Based on the characteristics of electric conductivity of brown rice, a pseudo electric circuit which has a resistance to represent the bio-electric behavior has been developed. Via calibration and regression computation, the response voltage measurements are used to predict the moisture contents of brown rice. The developed method can be used to the moisture contents real-time and nondestructively.
In this study, five different frequencies, 200KHz, 400KHz, 600KHZ, 800KHz and 1MHz are tested. The results of 200KHz and 400KHz do show the clear measurements, but they can not separate the measurements for different moisture contents clearly and precisely. Although the result of statistical analysis shows the existence of significant effect, this study still demonstrates the better outcomes form 600KHz, 800KHz, and 1MHz. The higher frequency will have the better results. For the tests of 1MHz, they expressed the good R2 of 0.97 and small deviation of -0.67 to 0.7. The F-value and P-value for 1MHz are much better than other frequencies.
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