Beam wave propagation within the second Rytov perturbation approximation

The applicability of the classical Rytov method in statistical wave propagation problems is reconsidered and expanded by demanding results that are of second order in the permittivity fluctuations, rather than limiting them to just the first Rytov perturbation approximation, as is traditionally done. It is shown that one must augment the well-known second order statistics (e.g., log-amplitude variance), as calculated from the first Rytov approximation, with first-order statistics (e.g., the average log-amplitude), as calculated from the second Rytov approximation. Thus, a complete solution is derived for the second Rytov approximation for general beam wave propagation through turbulent media, the permittivity fluctuations of which are described by the Kolmogorov-Obukhov spectrum. This then allows a complete and consistent treatment that yields the fact that the average log-amplitude is, in the general beam wave case, not equal to the additive inverse of the log-amplitude variance. This gives results from the Rytov method that are then in exact agreement with the corresponding limiting case of strong fluctuation theory, as well as a simplified analytical expression for beam wave broadening, and the correct theoretical explanation of the well-known applicability limit for the Rytov method.     

Kohlenwasserstoffe

Ohne Zusammenfassung     

How Not to Schedule a Stitching Room

This is a case study of a project to introduce computer-aided scheduling into the stitching room of a shoe factory, which led instead to an automated microcomputer-controlled work-handling system. The outcome has been an increase in productivity and wages earned, together with a large reduction in throughput time and work-in-progress.     

The use of SO2Cl2 in organometallic chemistry. Convenient high yield syntheses of [Fe(η-C5H5)(CO)3] [FeCl4] and [M(CO5Cl] (M = Mn or Re)

Depending on the substrate and the reaction conditions, SO₂Cl₂ is a useful reagent which brings about either chlorination or the formation of cationic species on reaction with transition metal carbonyl complexes.