14. Report
14.1 Report the rate index value as c, the viscosity as VIS100 and intercept as ln b. Label increasing and decreasing sweep data using INC and DEC.
14.2 Rate index c = dimensionless, three decimal places, x.xxx.
14.3 VIS100 = mPa·s, two decimal places xx.xx.
14.4 ln b = Pa, four decimal places, x.xxxx.
15. Precision
15.1 Precision was found to be dependent on the mean value of the measured property. The data in this section was derived from a six laboratory/six sample interlaboratory study and a three laboratory/seven sample interlaboratory study. All data was pooled to generate the repeatability and reproducibility data. VIS100 range was 14.99 to 36.28 mPa·s and rate index range was 0.623 to 1.002.
where:
x = mean value of rate index, and
y = mean value of VIS100 in mPa·s.
15.2 Sample Precision Calculations:
15.2.1 The maximum value for rate index is 1.000. This occurs for fluids which exhibit Newtonian behavior as observed for fresh diesel oils within the shear rate range of measurement in this test method. The rate index, DEC reproducibility for fresh oils would be:
0.490 - 0.480 (1.000) = 0.010
and for a drain with a value of 0.900:
0.490 - 0.480 (0.900) = 0.058
15.2.2 The VIS100 precision values are valid for viscosities within the scope of this test method, 12 to 35 mPa·s. A drain with a VIS100, DEC value of 15.20 mPa·s would have a repeatability of:
0.33 + 0.0066 (15.2) = 0.430
and a reproducibility of:
-0.54 + 0.073 (15.2) = 0.570
16. Keywords
16.1 drain oils; heavy duty diesel; rotational viscosities; shear thinning