EC24-721 Dairy Barns for Nebraska

The increasing interest shown among the farmers thruout this state in the betterment of dairy stock, and the tendency to give more attention to dairying on the farms, is bringing to the Agricultural College a great many requests for plans and suggestions for dairy barn construction. It is impossible to give every one of these inquiries individual attention to the extent of drawing a detailed plan to suit the conditions in each case. It is hoped therefore, that the material contained in this bulletin will offer helpful suggestions and answer many questions in the minds of prospective dairy men and dairy barn builders relative to the arrangement and construction of barns.

Perturbative analysis of the triply differential cross section and circular dichroism in photo-double-ionization of He

We extend application of our lowest-order perturbative approach (in electron-electron correlation) for analysis of photo-double-ionization (PDI) of He [A.Y. Istomin et al., J. Phys. B 35, L543 (2002)] to excess energies up to 450 eV and to analysis of circular dichroism. We find that account of electron correlation in the final state to first order provides predictions for the triply differential cross section and circular dichroism that are in reasonable agreement with absolute data for excess energies up to 80 eV. For an excess energy of 450 eV, account of electron correlation in both initial and final states is necessary and the predicted triply differential cross sections are in agreement with absolute data only for large mutual ejection angles. We find that at excess energies of a few tens of eV, the PDI is dominated by the "virtual" knock-out mechanism, while the "direct" (on-shell) knock-out process gives only small contributions for large mutual ejection angles. As a result, we conclude that the circular dichroism effect at these energies originates from the nonzero electron Coulomb phase shifts.