Secondary stress. A secondary stress is any stress in the structure which is not a primary stress or peak stress. Source: API SPEC 16R, Specification for Marine Drilling Riser Couplings, Exploration and Production Department, First Edition, January 1997. Global Standards.
Digger bees are sometimes classified in the family Anthophoridae along with the carpenter bees. These hairy bees range from 5 to 25 mm in length and, like other members of this family, the females use scopae (stiff hairs) to carry pollen. Most species nest in the ground or in vertical banks, often in sandy soil. Some species waterproof their brood cells with secreted waxy or oily material.
There are about 20,000 different species of bees in the world. Bees live in colonies that contain the queen bee, the worker bee and the drone. The worker bee and the queen bee are both female, but only the queen bee can reproduce. All drones are male. Worker bees clean the hive, collecting pollen and nectar to feed the colony and they take care of the offspring.