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.
Knowing the difference between the two will help you easily identify if you have bees helping around the house â or potentially harming it. The Common Eastern Bumblebee (Bombus Impatiens) is one of the friendlier flying and stinging insects. Known to be both unaggressive and harmless to your home, bumblebees play a very important role in pollination and in the production of honey. Xylocopa virginica, appropriately named the Carpenter Bee, is also a pollinator but known more for its woodworking abilities.