Sometimes the number of treatments to be compared is so large that a complete blocks experiment is impractical. This happens, for example, in some agronomic variety trials. A balanced incomplete block (BIB) design can be used in such a situation. In sensory evaluation trials loss of sensitivity can occur when the subjects are not be able to compare more than a few products with any certainty. A...

A modified Hartmann test for testing aspherical convex surfaces of F/# 1 is analyzed. We present the main differences of this test in comparison to the usual Hartmann test. Theoretical results show that the transverse aberrations yielded by a testing surface have to be measured with respect to its mean sphere. A method to determine the mean sphere is also presented. Experimental results show th...