Intrinsic dispersivity of randomly packed monodisperse spheres

We determine the intrinsic longitudinal dispersivity l(d) of randomly packed monodisperse spheres by separating the intrinsic stochastic dispersivity l(d) from dispersion by unavoidable sample dependent flow heterogeneities. The measured l(d), scaled by the hydrodynamic radius r(h), coincide with theoretical predictions [Saffman, J. Fluid Mech. 7, 194 (1960)] for dispersion in an isotropic random network of identical capillaries of length l and radius a, for l/a=3.82, and with rescaled simulation results [Maier et al., Phys. Fluids 12, 2065 (2000)].     

THYMINE HYDRATE FORMED BY ULTRAVIOLET AND GAMMA IRRADIATION OF AQUEOUS SOLUTIONS

Abstract— Evidence is presented for the formation of a thymine hydrate upon ultraviolet (UV) or gamma irradiation of aqueous solutions. The UV quantum efficiency exhibits a dependence on pH similar to that shown for uracil hydration, but the yield is three orders of magnitude smaller than for uracil. Hydration is not affected by wavelength, oxygen, or concentration of thymine. The reversal rate of the photohydrate to thymine is similar to the reversal rates of both isomers of the thymine hydrate formed by γ radiolysis, and depends on pH in the same way as the rate for the uracil photohydrate. The photohydrate of thymine is chromatographically identical to the cis isomer of 6-hydroxy-5, 6-dihydrothymine.     

Cyclopolymerisation. 5. Mitt. Das13-C-Spektrum und die Struktur des niedermolekularen Produktes aus der Reaktion von N-Methyl-N, N-diallylamin mit Azobisisobutyronitril

Ohne Zusammenfassung     

The ν2 fundamental band of H2CO

The ν₂ fundamental band of H₂CO has been studied using a combination of sub-Doppler laser Stark spectroscopy and Doppler-limited Fourier transform spectroscopy. A combined analysis of the Stark and Fourier infrared data together with previous microwave data on the ν₂ = 1 state yielded improved molecular parameters for formaldehyde, including the excited state dipole moment. A small perturbation was noted at K′_a = 7 which may be ascribed to a ΔK_a = 2 interaction with the v₃ = 1 state. Precise treatments of ν₂ with K′_a > 6 will thus require a combined analysis taking into account Coriolis interactions among ν₄, ν₆, ν₃, and ν₂.     

Numerical integration of the shallow water equations over a sloping shelf

A finite-difference method is described for the numerical integration of the one-dimensional shallow water equations over a sloping shelf that allows for a continuously moving shoreline. An application of the technique is made to the propagation of non-breaking waves towards the shoreline. The results of the computation are compared with an evaluation based upon an exact analytical treatment of the non-linear equations. Excellent agreement is found for both tsunami and tidal scale oscillations.