SENSITIVITY, DEFECT (RT): The minimum dimension of a discontinuity, considered to be a defect, that can be
detected in a radiograph under specified conditions.
SENSITIVITY, IQI (RT): See IQI SENSITIVITY.
SENSITIVITY (PERCENTAGE): A ratio of the smallest detectable thickness difference divided by the thickness of
material being examined.
SENSITIVITY, RADIOGRAPHIC: The ratio of the smallest difference in thickness that is detectable on the radiograph
to the thickness of the specimen. It may be expressed as a percentage, and is an indication of ability to detect a small
discontinuity. In practice, it is determined by the use of an image quality indicator (penetrameter).
SENSITIVITY, SPECTRAL (RT): The variation in radiographic exposure, as a function of X-ray energy, required to
produce a given film density.
SENSITOMETRIC CURVE (RT): See CHARACTERISTIC CURVE.
SENSITOMETRY (RT): A quantitative measurement of the response of a film to exposure and development.
SEPARATION ANGLE: The angle on the impedance plane between the thickness change curve and the lift-off curve
for a specific material.
SETTLING TEST (MT): See CONCENTRATION TEST.
SG: See DISTANCE AMPLITUDE CORRECTION.
SHADOW (UT): A region in a body, which cannot be reached by ultrasonic energy, traveling in a given direction;
caused by the geometry of the body or a discontinuity in it.
SHALLOW DISCONTINUITY: A discontinuity open to the surface of a solid object which possesses little depth in
proportion to the width of this opening. A scratch or nick may be a shallow discontinuity in this sense.
SHALLOW-DOSE EQUIVALENT: As it applies to external exposure of the skin or an extremity, is taken as the dose
equivalent at a tissue depth of 0.007 centimeters (7 mg/cm2) averaged over an area of 1 square centimeter.
SHARPNESS (RT): See definition RADIOGRAPHIC (RT).
SHEAR: That type of force which causes or tends to cause two contiguous parts of the same body to slide relative to
each other in a direction parallel to their plane of contact.
SHEAR FRACTURE: A fracture in which a crystal (or a polycrystalline mass) has separated by sliding or tearing under
the action of shear stresses.
SHEAR LIP: A narrow, slanting (hence shear) ridge along the edge of a fracture surface. The term sometimes also
denotes a narrow, often crescent-shaped, fibrous region at the edge of an otherwise cleavage fracture, even though this
fibrous region is in the same plane as the rest of the fracture surface.
SHEAR STRENGTH: The stress required to produce fracture in the plane of cross-section, the conditions of loading
being such that the directions of force and of resistance are parallel and opposite although their paths are offset a
specified minimum amount.
SHEAR WAVE (UT): A type of wave in which the particle motion is perpendicular to the direction of propagation.