Wall Geometry Optimization

Fig. 4. Structure and coordination of the Cu2+ cation located on top of the six-member ring on the zeolite channel wall. Geometries optimized with various models.

The improvement of heat transfer by optimized channel and wall geometries and the choice of best-suited materials contribute to the enhancement of process speed and to a better control of selectivity. Adapted selectivity can be achieved by realizing well-defined temperature proto-... 

We have carried out a series of geometry optimizations on nanotubes with diameters less than 2 nm. We will present some results for a selected subset of the moderate band gap nanotubes, and then focus on results for an example chiral systems the chiral [9,2] nanotube with a diameter of 0.8 nm. This nanotube has been chosen because its diameter corresponds to those found in relatively large amounts by Iijima[7] after the synthesis of single-walled nanotubes. 

Productivity is directly related to cycle time. There usually is considerable common knowledge about a geometry and process conditions that will provide a minimum cycle time. Practices such as using thinner wall sections, cold or hot runners for TPs or hot or cold ones for TSs narrow sprues and runners, the optimal size and location of coolant (or heat) channels, and lower melt or mold heat, will decrease the solidification time reducing the cycle time. 

Technical constraints are often imposed on the design of the monolith geometry by the extrusion process, as well as by the mechanical properties of the extrudate the specific SCR application (e g., high-dust vs. low-dust) is also crucial for the definition of the catalyst geometrical features. Here, attention is paid to the influence that the monolith parameters (wall thickness, channel size, channel shape) have on both DeNOx reaction and SO2 oxidation in order to advance guidelines for optimization of the catalyst geometry. 

The preliminary investigation showed that lower pressures result in significantly higher heat fluxes. It s possible to approaeh 50 W/em while maintaining the wall temperature below 85 °C with little optimization. A more eomprehensive parameterization study will be addressed such as pore size, geometry, and other effeets as the limits of graphite foam evaporator performance [34-35]. 

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