日本金属学会誌

J. Japan Inst. Metals, Vol. 59, No. 8 (1995),
pp. 846-850

Characteristics of Image Data Processing Techniques for Sessile Drop Method

Takehiro Dan, Kohmei Halada and Yuji Muramatsu

National Research Institute for Metals, Tsukuba

Abstract:

Both profile fitting and curvature plotting methods have previously been submitted as new image processing techniques in the sessile drop method by the authors. The purpose of this research is to elucidate the characteristics and the applicable limits of these data processing methods (including the traditional Bashforth and Adams method) and in turn submit a guide to their choice. Both theoretical sessile-drop profile as a solution of Laplace equation and sessile drop profile from the present experiment are processed by the above methods. As a result, the precision and the optimal applicable range of these methods are discussed.
The results obtained are as follows. (1) Under the present processing conditions, the precision of the profile determination is estimated to be {±}1.3 μm. This value is comparable to that obtained with an optical projecting magnifier which is usually used in the traditional Bashforth and Adams method. (2) The error in the data processing through the use of the profile fitting method is determined to be less than 0.1%, independent of the number of profile data points (more than 130 points). (3) The precision of the presumed β-value, which was defined by Bashforth and Adams, by the curvature plotting method is dependent on the number of profile data points definitely. However, the curvature plotting method is optimal in order to inspect a local little change in the sessile drop profile. (4) The traditional Bashforth and Adams method is very simple and requires only a few measuring points. However, it is apparent that the confirmation of fitting of an experimental profile with a recalculated profile from the obtained β-value is indispensable. (5) The surface tension of an Au20 at%-Ag80 at% alloy at 1375.15 K in Ar-7 vol%H2 atmosphere was determined to be 914.0 mN/m. This value was in good agreement with the reference data.


(Received December 26, 1994)

Keywords:

profile fitting method, curvature plotting method, sessile drop, Bashforth and Adams method, Laplace equation, image processing


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