The coarse-mesh finite difference (CMFD) method is commonly used to accelerate the iterative convergence of single-physics neutron transport problems. For multiphysics problems, cross sections depend on temperature and density, both which fission heat source; resulting nonlinear feedback can significantly degrade performance CMFD even cause instability. In this paper, we propose, for a class on...

Leaves are extraordinarily variable in form, longevity, venation architecture, and capacity for photosynthetic gas exchange. Much of this diversity is linked with water transport capacity. The pathways through the leaf constitute a substantial (>or=30%) part of the resistance to water flow through plants, and thus influence rates of transpiration and photosynthesis. Leaf hydraulic conductance (...

A rigorous model for staged high purity distillation based on rst principles is developped. The importance of the tray hydraulics to obtain good agreement between simulation and experiment is demonstrated. Analytical expressions to derive the hydraulic time constants l, v and the vapor constant for models with simpli ed tray hydraulics are presented. The validity of these key parameters is veri...