Interaction of polyvinylpyrrolidone and iodine

A nonsolvent preparation of the polyvinylpyrrolidone (PVP) complex provides new insight into the nature of the polymer-iodine interaction. The preparation is obtained by simply mixing PVP with crystalline iodine and is of interest because it provides a system in which no interfering ions are present and only one type of iodine is initially present. The iodine is shown to undergo hydrolysis with moisture in the polymer to give iodide and hypoiodite. The ionic forms of iodine appear to associate with the molecular iodine, resulting in the final stable PVP-iodine complex.     

Fusion Reaction Gas Chromatography

The conventional gas chromatograph is an efficient tool for separating mixtures of volatile compounds into their individual components for quantitative measurement and for preparative isolation of the components. Many compounds, however, are nonvolatile or lack sufficient volatility for gas chromatographic separation. These compounds may contain polar functional groups (i.e.r -COOH, -OH, -NO₂ -NH₂, etc.), which cause low volatility or poor chroma tographic behavior, or ionic groups (i.e., -SO₃Na, R₄NX-SO₄Na, -WNCl, etc.), which are either completely nonvolatile or thermal unstable. Other compounds have too large molecular weights for conventional gas chromatographic separation.     

Fluctuations about hydrodynamic nonequilibrium steady states

Using an extension of the Langevin method, we calculate the fluctuations of a fluid about a stationary state held away from global thermal equilibrium by a temperature gradient or shear flow. In the former case, the Brillouin peaks in the light scattering spectrum acquire an asymmetry that is qualitatively similat to earlier results but different in detail.     

Cascade model of fully developed turbulence

A simple system of quadratically nonlinear equations representing a hierarchy of frequency scales is derived from a cutoff version of Burgers' equation. When forced, the model system reproduces a number of qualitative features of fully developed turbulence. In equilibrium, the model exhibits, in addition to the energy, an extensive isolating integral of the motion that is cubic in the velocity.This work was aided by a direct grant of computer time from NCAR. This work was in part supported by the National Science Foundation under Grant No. ENG 7408501A02.