The latest development in screw compressor (helical lobed compressor) rotor profile design and rotor manufacturing machinery have prioritized basic rotor profile surface, lead and divide. However, one error that at frrst looks very basic but at the same time almost impossible to eliminate, is dealt with in this paper. The error is rotor runout.

2014 The stability of a screw dislocation in a SmA phase submitted to a dilative or compressive strain normal to the layers is investigated. It is shown that the screw line transforms to a helical line, whose handedness depends on the signs of the Burgers’ vector and of the strain. For small strains the process necessitates some activation energy; there is a critical strain above which it is sp...

We present a method of helical long-period fiber grating (H-LPFG) fabrication by use of a CO2 laser for use as an optical torque sensor. A conventional optical fiber grating has periodic vertical index changes along its fiber axis, but a H-LPFG has a screw-type index modulation. The helical index modulation is obtained with the asymmetric index change caused by a single-side laser beam exposure...