pattern(redirected from Geometric patterns)
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(also, development), in geometry. The pattern of a polyhedron is a set of polygons for which it is shown how the sides and vertices of the polygons must be joined in order to ob-
tain the polyhedron. Several conditions must be met here: each side of a polygon must be joined to no more than one side of another polygon; it must be possible to pass from one polygon to another polygon by traversing pairwise joined polygons; and joined sides must have equal lengths. The pattern of a cube is shown in Figure 1.
In such fields as descriptive geometry and drafting, the concept of pattern is sometimes applied to curved surfaces. Thus, the pattern of the lateral surface of a cone is a sector of a circle (Figure 2).
(Russian, shablom), in foundry production, an element of a gated pattern, consisting of a flat device whose working side has a highly accurate profile. A distinction is made between molding and control patterns. The former, in the form of wooden boards, are used in individual and small-series production; they take the place of a solid casting pattern or corebox in the manufacture of casting molds and mold cores for medium-size and large castings having the outline of a body of revolution (such as cups, vats, covers, and pulleys). The cavity of the mold or the working surface of the core is produced by rotating the molding pattern around its central axis (a core spindle is positioned at this place in the mold). Control patterns are made of plywood or sheet steel and are used for checking the accurate placement of cores in the cavity of a casting mold during assembly and preparation for pouring.
M. N. SOSNENKO
ii. Radiation of the transmitting aerial as plotted on a diagram of the field strength for each bearing.
iii. A shape traced out on the ground by the track of the aircraft while following certain procedures, such as making the circuit, making procedure turns, while holding, and while carrying out demonstrations. See circuit and holding pattern.