The goal of this paper is to express the Bach tensor of a four dimensional conformal geometry of an arbitrary signature by the Cartan normal conformal (CNC) connection. We show that the Bach tensor can be identified with the Yang–Mills current of the connection. It follows from that result that a conformal geometry whose CNC connection is reducible in an appropriate way has a degenerate Bach te...

Axial twisting of the torso has been identified via epidemiologic studies as a significant risk factor for occupationally-related low back disorders. However, only recently have biomechanical studies been able to describe how twisting is accomplished through the use of the trunk musculature. These studies have been performed on subjects whose torso twists were performed in an upright posture. I...

Occupational-related low back disorders are the leading cause of lost work days as well as the most costly occupational safety and health problem facing industry today. Twisting has been found to be associated with lower back pain (Frymoyer, 1983). Previous biomechanical measures of twisting allowed ancillary moments and forces in addition to the twisting exertion. This confounding makes it dif...

Consider an effective Hamiltonian torus action T ×M → M on a topologically twisted, generalized complex manifold M of dimension 2n. We prove that the rank(T ) ≤ n − 2 and that the topological twisting survives Hamiltonian reduction. We then construct a large new class of such actions satisfying rank(T ) = n − 2, using a surgery procedure on toric manifolds.

Twisting is an important process to form a continuous yarn from short fibres and to determine the structure and properties of the resultant yarn. This paper proposes a new theoretical model of yarn dynamics in a generalized twisting system, which deals with two important phenomena simultaneously, that is, twist generation and twist propagation. Equations of yarn motion are established and the b...

applications of thermoplastic composites have developed extensively. the thermoplastic composites in comparison with the thermoset composites have many advantages. thermoplastic composites can be melted and remolded many times. the duration of manufacturing process of these composites is short, producing very tough material, and the welding ability and multiple recyclings are their further adva...