Stigma (letter) Stigma (letter) Stigma (ϛ) is a ligature of the Greek letters sigma (Σ) and tau (Τ), which was used in writing Greek between the Middle Ages and the 19th century. It is also used as a numeral symbol for the number 6. In this unrelated function, it is a continuation of the old letter digamma (originally Ϝ, cursive form ), which had served as a numeral since antiquity and was conflated with the σ-τ ligature in the minuscule handwriting of the Middle Ages. The στ ligature (, ) was one of many ligature forms that came into widespread use as
Damping torque Damping torque Damper is a generic term used to identify any mechanism used for vibration energy absorption, the shaft vibration suppression, soft start and overload protection device. In order to design an efficient damper, it is imperative that the damping torque is calculated first. Damping torque or damping forces is the speed deviation of an electromechanical torque deviations of a machine while the angle deviation is called synchronizing torque [1]. In a measuring instrument, the damping torque is necessary to bring the moving system to rest to indicate steady reflection in a reasonable short time.It exists only as long as