A method evaluates a plurality of candidate index sets for a workload of database statements in a database system by first generating baseline statistics for each statement in the workload. The frame is turned to an aperture angle with respect to the frame support, and each airfoil profile is turned to a profile angle with respect to the frame. The resulting alkoxysilane product does not give rise to the quality problem that the product will gradually whiten during storage owing to contact with air.