1988 At least 164 people are killed in
twin plane crashes in India.
The term "polysynthetic" corresponds to the case when three or more individuals are repeated alternatively on the same
twin plane. The lamellas are joined on successive
twin planes, parallel with elongation (Figure 2).
Murai et al (1976) [7] conducted experiments on
twin plane incompressible jets issuing at an angle from the nozzle exit plane.
(1961) and Mason and Berry (1968) all cite heart-shaped contact twins with twin and composition plane (201 } as "common." However, each of these authors chose a different unit cell orientation, yet cited the same
twin plane as the most common!
It is estimated that a
twin plane, stay-cable system would have required 23 percent more cable grout and 52 percent more weight of cable sheathing than the single plane system.
Murai et al (1976) [6] conducted experiments on
twin plane incompressible jets issuing at an angle from the nozzle exit plane.
These twins are not as obvious as the flattened twins from Peru, Dalnegorsk and Bulgaria; Mogul mine galena twins are blocky, with only a hint of a re-entrant angle on the
twin plane. A few rare examples, such as the one in Figure 6, do show a parallel growth accompanied by some flattening.
These parallel lines are attributed to polysynthetic
twin planes corresponding to the rhombohedral {1011} faces of corundum.
Coppelius, here an inventor of photographic images, walks home alternately across the stage and on film, setting up Marin's
twin planes of reality for this urban fairy tale with hardly a trace of cynicism.
The other two symmetry planes are identical to the Baveno
twin planes {021}.