The cylindrical cell approximation in thermal utilization

In solving the neutron diffusion equation in one cell of an infinite lattice, a common procedure is to replace the rectangular (or hexagonal) cell with an equivalent cylindrical cell. In order to estimate the effect of this approximation a new method is presented in which the flux in the entire cell (not the equivalent cylindrical cell) is expanded in a Fourier cosine series. Then the boundary conditions over the cell surface are satisfied exactly. Furthermore, algebraic equations for the expansion coefficients of the flux are obtained because the integrals over the cell can be done in closed form. It is found that truncation of the flux series after 10 terms gives good results. The method is felt to have more general application than to the actual problem treated here since such `mixed geometry' problems frequently arise in reactor physics and in other areas as well.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33375/1/0000773.pd

Changing youth? : continuities and ruptures in transitions into adulthood among Catalan young people

The globalisation process has an impact at the micro-level on life-course patterns: concretely, the trajectories of young people into adulthood are being sharply modified. At a European level, the extension, de-linearisation, reversibility and diversification of youth trajectories have been identified as major changes. However, the extent to which these changes affect young people within each country depends on their respective welfare regimes. This article analyses how the Mediterranean welfare regime shapes youth trajectories among Catalan young people and explores the hypothesis that these constraints will make those trajectories less sensitive to the general trends of change identified at a European level. The research is based on an analysis of the Catalan Youth Survey, an official statistic that contains retrospective data on Educational, Work, Housing and Family transitions. The results offer an integrated typology of youth transitions in Catalonia and show how the persistence of traditional patterns of transition are the logical result of the particular articulation of the welfare regime and cultural patterns among Catalan young people