Feeding–Danger Trade-Offs Underlie Stopover Site Selection by Migrants

A piston for an internal combustion engine with a separate head and skirt which are joined by a piston pin. The ring belt extends downward from the head and terminates above the pin. The space between the lower edge of the ring belt and a section of the head defines a cooling oil ring space. A depression is formed in the head and is partly defined by the section. The section has a thickness of between four percent and seven percent of the piston diameter, corresponding to an angle of zero to sixty degrees of the section with respect to a vertical longitudinally extending line. The thickness of the head above the space is six percent to twelve percent of the piston diameter. The top of the space is below the top ring groove. Above the second ring groove, the ring belt has a thickness of greater than two and one-half percent of the piston diameter.