screw axis


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screw axis

[′skrü ‚ak·səs]
(crystallography)
A symmetry element of some crystal lattices, in which the lattice is unaltered by a rotation about the axis combined with a translation parallel to the axis and equal to a fraction of the unit lattice distance in this direction.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The drum contains 8 or 10 (depending on the model size) small extruder barrels, parallel to the main screw axis. Installed in these small extruder barrels are the "satellite" screws, which are driven by a ring gear in the main barrel.
In the position ([lambda],[mu]) of motion the lines have a velocity vector with stationary norm, locus of the lines which called instantaneous screw axis. The equations
Right or left trapezohedrons occur in pairs at every other prism edge and actually define a two-fold screw axis (follow the blue line in Figs.
The extrusion drum contains eight or ten small extruder barrels, parallel to the main screw axis. These small extruder barrels hold the satellite screws, which are driven by a ring gear in the main barrel.
The MRS consists of a large single-screw drum containing 8-10 (depending on the model size) small extruder barrels, parallel to the main screw axis. The satellite screws installed herein rotate in the opposite direction of the main screw, disproportionally increasing the surface exchange of the polymer melt.
The pellet bed moves along the screw axis, due to the pushing forces exerted by the screw flights, with the velocity equal to
The first coordinate system, X'(x', y', z'), is fixed with its z' axis accordant with the axis of the screw, and x' y' plane is perpendicular to the screw axis. The second coordinate system, X(x, y, z), is used to describe the rotation of the screw rotate [OMEGA] around z' axis.
(d) Detailed view of (c), the screw distance to the subchondral bone of the acetabulum (red to blue dot) was measured on a vertical line to the screw axis through the center of the femoral head.
The morphology of the specimens at different positions along the screw axis was investigated by a scanning electron microscope.
Grooves run parallel to the screw axis. One machine supplier, Battenfeld Gloucester Engineering Co., used to build helical grooves, but several years ago switched to notched axial grooves.
Figures 7 and 8 show SEM observations of blends of polyamide 6 and polypropylene and the changes of mass average and weight average value along the screw axis for configuration A.