Concrete reinforced with fibers (which are usually steel, glass, or plastic fibers) is less expensive than hand-tied rebar, while still increasing the tensile strength many times. The shape, dimension, and length of the fiber are important.
1. ozone hole-an area of the ozone layer (near the poles) that is seasonally depleted of ozone. hole-an opening into or through something. ozone layer, ozonosphere-a layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun.ole-an opening into or through something. ozone layer, ozonosphere-a layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun.
The ozone hole area is defined as the size of the region with total ozone below 220 Dobson units (DU). Dobson Units are a unit of measurement that refer to the thickness of the ozone layer in a vertical column from the surface to the top of the atmosphere, a quantity called the total column ozone amount.. Prior to 1979, total column ozone values over Antarctica never fell below 220 DU.