ASTM D971 for Interfacial Tension of Oil Against Water by the Ring Method
11. Report
11.1 Report the following information:
11.1.1 Identification of test specimen,
11.1.2 Density used for calculations (water and test specimen), and
11.1.3 Test method used and interfacial tension in mN/m.
12. Precision and Bias
12.1 The following criteria should be used for judging the acceptability of results (95 % confidence).
12.2 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.04 X , where X denotes mean value.
12.2.1 Reproducibility - The difference between two single and independent results, obtained by different operators working identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.10 X , where X denotes mean value.
12.3 Bias - There being no criteria for measuring bias in these test-product combinations, no statement of bias can be made.
13. Keywords
13.1 interfacial tension; surface tension; tensiometer; transformer oil
