Practitioner Research as a Way of Knowing: A Case Study of Teacher Learning in Improving Undergraduates' Concept Acquisition of Evolution by Natural Selection.

A sintered powder metal (P/M) component has an integrally formed tapered boss surrounding its bolt hole which extends into counterbores in a component to which it is assembled and produces plastic conformance between the boss and the counterbore when the boss is seated in the counterbore. The P/M component can then be removed from the other component and reassembled to it, with the boss fitting perfectly back into the bore with the plastically deformed surfaces fitting back together precisely to determine the relative positioning of the two components. The boss is tapered, a moat may surround it, and the boss may be provided with axial splines and/or be oblong in the axial direction. Bosses such as these may be applied to two components in general, at least one of which is powder metal, such as a main bearing cap, a sensor ring for measuring the timing of an internal combustion engine and a connecting rod bearing cap. Such bosses may also be applied to a casting insert in which the boss is crushed when the die is closed so as to seal off the surrounded hole during casting.