Torsion
Encyclopedia
The word torsion may refer to the following:
- In geometry:
- Torsion of a curve
- Torsion tensorTorsion tensorIn differential geometry, the notion of torsion is a manner of characterizing a twist or screw of a moving frame around a curve. The torsion of a curve, as it appears in the Frenet-Serret formulas, for instance, quantifies the twist of a curve about its tangent vector as the curve evolves In the...
in differential geometry - The closely related concepts of Reidemeister torsion (also called R-torsion, Franz torsion, de Rham torsion) and analytic torsion (also called Ray-Singer torsion)
- Whitehead torsionWhitehead torsionIn geometric topology, the obstruction to a homotopy equivalence f\colon X \to Y of finite CW-complexes being a simple homotopy equivalence is its Whitehead torsion \tau, which is an element in the Whitehead group Wh. These are named after the mathematician J. H. C...
- In algebra:
- Torsion (algebra)
- Tor functorTor functorIn homological algebra, the Tor functors are the derived functors of the tensor product functor. They were first defined in generality to express the Künneth theorem and universal coefficient theorem in algebraic topology....
- In medicine:
- Ovarian torsionOvarian torsionOvarian torsion refers to the rotation of the ovary to such a degree as to occlude the ovarian artery and/or vein.-Epidemiology:Ovarian torsion accounts for about 3% of gynecologic emergencies. In 70 percent, it is diagnosed in women between 20 and 39 years. The risk is greater during pregnancy...
- Testicular torsionTesticular torsionTesticular torsion is when the spermatic cord to a testicle twists, cutting off the blood supply. The most common symptom is acute testicular pain and the most common underlying cause is a congenital malformation known as a "bell-clapper deformity". The diagnosis is often made clinically but if it...
- Spiral fractureSpiral fractureA spiral fracture is a bone fracture occurring when torque is applied along the axis of a bone. While torsional forces are being applied along the parallel axis of a bone, planes perpendicular to this axis are not affected. Tension is exerted upon one part of the bone, while compressive forces are...
, a.k.a. Torsion fracture - BloatBloatBloat is a medical condition in which the stomach becomes overstretched by excessive gas content. It is also commonly referred to as torsion, gastric torsion, and gastric dilatation-volvulus when the stomach is also twisted. The word bloat is often used as a general term to cover gas distension...
particularly in cattle and dogs - Horse colic#Torsion
- Ovarian torsion
- In physics and engineering:
- Torsion (mechanics)Torsion (mechanics)In solid mechanics, torsion is the twisting of an object due to an applied torque. In sections perpendicular to the torque axis, the resultant shear stress in this section is perpendicular to the radius....
- Torsion coefficient
- Torsion pendulum
- Torsion springTorsion springA torsion spring is a spring that works by torsion or twisting; that is, a flexible elastic object that stores mechanical energy when it is twisted. The amount of force it exerts is proportional to the amount it is twisted. There are two types...
or -bar - Torsion field (pseudoscience), a theory by Russian scientists
- Torsion (mechanics)
- In biology:
- Torsion (gastropod)Torsion (gastropod)Torsion is an anatomical event which takes place during the very early part of the life of snails and slugs of all kinds. In other words, torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle and shell 180˚...
, a developmental feature of all gastropods
- Torsion (gastropod)