Their hymenal opening tends to be annular (circumferential). Therefore, annular and cylindrical Hall thrusters have limited lifetime. This can be controlled using the annular and longitudinal muscles. An engine that uses an annular combustor is the CFM International CFM56. Combustor configurations include can, annular, and can-annular. The cooling of annular cutters is internal. Using lubricant or coolant with any type of annular cutter is a must. The Sanskrit adjective ' means "circular, annular". There are a number of variations in snap-fits, including cantilever, torsional and annular. The annular embryo surrounds the perisperm. The original spoilers were removed and replaced by a single ring below the annular flap. He demonstrated the ability to image atoms using an annular dark field detector. Ribbon and ring parachutes have similarities to annular designs. In partial and annular eclipses, only part of the Sun is obscured.