North Africa, region of Africa comprising the modern countries of Morocco, Algeria, Tunisia, and Libya. North AfricaEncyclopÃ¦dia Britannica, Inc.The geographic entity North Africa has no single accepted definition.
A Stressor is anything (physical or psychological) that produces stress (negative or positive) is considered a stressor.
Stress concentration. A stress concentration (often called stress raisers or stress risers) is a location in an object where stress is concentrated. An object is stronger when force is evenly distributed over its area, so a reduction in area, e.g., caused by a crack, results in a localized increase in stress.