Project/Area Number  07556040 
Research Category 
GrantinAid for Scientific Research (B)

Section  試験 
Research Field 
林産学

Research Institution  SHIZUOKA UNIVERSITY 
Principal Investigator 
SOBUE Nobuo SHIZUOKA UNIVERSITY,FACULTY OF AGRICULTURE,PROFESSOR, 農学部, 教授 (50023495)

CoInvestigator(Kenkyūbuntansha) 
KIMURA Shiro NAGOYA UNIVERSITY,FACULTY OF AGRICULTURE,ASSOCIATE PROFESSOR, 農学部, 助教授 (30023443)
HIRAI Nobuyuki SHIZUOKA UNIVERSITY,FACULTY OF AGRICULTURE,PROFESSOR, 農学部, 教授 (70023439)

Project Fiscal Year 
1995 – 1996

Project Status 
Completed(Fiscal Year 1996)

Budget Amount *help 
¥3,800,000 (Direct Cost : ¥3,800,000)
Fiscal Year 1996 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1995 : ¥2,700,000 (Direct Cost : ¥2,700,000)

Keywords  High frequency moisture meter / Density correction / Measurement of moisture gradient / Electrode scanning / Simultaneous measurement of density and moisture content / Inverse solution / 高周波容量式水分計 / 密度補正 / 水分傾斜測定 / 電極走査 / 密度含水率同時計測 / 逆解法 / 自動密度補正 / 水分傾斜測定機能 / 電極間隔 / 実効電界深度 
Research Abstract 
Development of the functions for density correction and moisture gradient measurement of high frequency moisture meter was investigated. In order to evaluate the moisture gradient, an electrode scanning method was proposed. In this method, the capacitance change in function of electrode distance was measured. The capacitance curve pattern showed good correlation with the moisture gradient pattern. The capacitance change due to electrode scanning C (d) was defined as the following integral equation, C (d)=* S (d, x) U (x) dx, where S (d, x) is a weight function and U (x) is a moisture gradient. In order to solve this equation, a linear simultaneous equation was introduced. The weight function was experimentally determined from model specimens with different moisture gradient. Simulation research was made to investigate the relationship between the capacitance curve and the moisture gradient. The following results were obtained : (1) In these high frequency moisture meter, the capancitance is sensitive very much to the moisture condition near electrodes. (2) The capacitance decreases exponentially with increase of the electrode distance. (3) As the electrode distance increases, relative sensibility of deep position increases. (4) The inverse solution of moisture gradient was not stable, and the reproduce of the moisture gradient was insufficient. Father mathematical treatment should be required. (5) Practical application of the results is to classify the spectrum patterns of the capacitance curves. Wood density affects very much on the measurement of a high frequency moisture meters. In this research, a simultaneous determination of a density and moisture content was proposed, and the following algorism was examined. The Kollmann's densitymoisture content figure was combined with the result of the reading of a moisture meter. These values converged in two or three times of iteration, and the propriety of the proposed algorism was confirmed.
