Triangular prisms

Formed by adding atoms beyond each of the vertical faces of a right triangular prism. 0.732... 

For the Si condition, the triangular prism is fastened to a horizontal surface such that the prism cannot translate in either the x- or y directions. Thus, u = 0 and v = 0. exist. 

For the S2 condition, the triangular prism is supported on partially embedded y-direction roller bearings that permit translation in the x-direction, but none in the y-direction. Thus, us O and v = 0. Hence, force must be zero, but N y must exist. 

Prisms and pyramids are described by their bases a triangular prism has a triangular base, a parallelpiped is a prism whose base is a parallelogram and a... 

The crystal structure of CrB is made up of independent layers of Cr atom prisms parallel to (010) with the prism axes running in the (100) direction. The prisms are centred by B atoms which form zigzag chains running in the (001) direction. This structure may also be considered as a development from the A1B2 in which the contiguous triangular prisms are separated into independent layers and displaced relative to each other by a/2, c/2 referred to the axes of the CrB cell (Pearson 1972). 

In the Fe2P-type structure there are four different groups of equipoints. The distribution of P and Fe atoms in different groups of positions is reported. A number of isostructural binary compounds are known. To the same structure, however, ternary or even more complex phases may be related if different atomic species are distributed in the different sites. This structure can be considered as an example of more complex structures built up by linked triangular prisms of Fe atoms. 

The lanthanide sulphides show pol5unorphism and contain mixed coordination polyhedra and coordination numbers. The sulphides of La—Dy M2S3) form orthorhombic (A-t5q)e) crystals, where there are two kinds of nonequivalent cations (229, 230), one is heptacoordinated (monocapped triangular prism), and the other is octacoordinated (bicapped trigonal prism). Monoclinic (D-type) sulphides are formed by Dy—Tm and Y (229, 231) and contain both hexacoordinated and heptacoordinated lanthanide ions. The rhombohedral (E-type) sulphides of Yb and Lu contain only hexacoordinated metal ions (229). 

Further oxidation of the nine-atom clusters to formal [Ge9] leads to linear polymers oi[-Ge9-] with two covalent intercluster bonds (Fig. 2i). Trimers [Ge9=Ge9=Ge9] (Fig. 6a) and tetramers [Ge9=Ge9=Ge9=Ge9] (Fig. 6b) occur via nonclassical bond formation between two neighboring atoms of the triangular prism basis planes of the c/oio-shaped clusters, which results in Ge-Ge-Ge bond angles of 90° and in considerably longer Ge-Ge contacts between the cluster units. Quantum-chemical calculations have shown that the exo-bonds participate in a delocalized electronic system that comprises the whole anion [204]. 

The terminology of computational techniques is descriptive, but one needs to know what is being described. Table 7.1 lists some common terms with a definition relative to mass transport. Most computational techniques in fluid transport are described with control volume elements, wherein the important process to be computed is the transport across the interfaces of small control volumes. The common control volumes are cubes, cylindrical shells, triangular prisms, and trapezoidal prisms, although any shape can be used. We will present the control volume technique. 

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