Elliptical monoliths

Pop III stars in classic monolithic models for ellipticals (closed-box) produce larger, although still acceptable, [< Mg/Fe > ] ratios. However, the predicted integrated colors are too red. As a consequence these models should be rejected. 

The fabrication of ceramic monoliths is performed mainly via extrusion techniques [9] resulting in usually elliptic or squareshaped monoliths. Cell densities as high as 1600 cells per square inch (cpsi) are achieved [9], which corresponds to a channel width of about 500 pm of the mostly rectangular or hexagonal channels. Typical key features are 75% porosity and a geometric surface area of 2.8 m /1 for 400 cpsi for ceramic monoliths [10]. The thermal shock resistance amounts to 800°C and higher. 

Ceramic monoliths (see Figure 6.1) are produced mainly by extrusion techniques [130]. The cross-section of the monoliths is usually elliptic or square. Up to 1600 cells per square inch (cpsi) may be achieved by this technique [130], which corresponds to a channel width of about 500 pm. The shape of the channels is usually rectangular or hexagonal. More than 75% porosity may be achieved in ceramic monoliths [136]. The geometric surface area is 2.8 m for 400 cells per square inch... 

When in these equations the second partial derivatives of Y and co with respect to z are neglected,which is justified because in the monolithic convertor the convective transport of vorticity in the axial direction is greater than the axial diffusive transport, the elliptic differential equations change into parabolic equations. 

Flow distribution has been essentially studied in cylindrical monoliths (Wendland and Matthes (1986), Howitt and Sekella (1974), Lemme and Givens (1974)). Elliptical and race-track monoliths have been studied by Wendland and Matthes (1986) and Leclerc et al. (Leclerc et al. (1989a, 1989b, 1990)). The main conclusions of these authors are ... 

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