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The local elastic strength κ, segmental friction coefficient ζ, and the Brownian force intensity B of polymer chains in a melt are expected to change under fast flow. This study examined the effects of those changes on rheological and structural properties of the Rouse model, the most frequently utilized model for unentangled melts. Specifically, the Langevin equation of the Rouse model was solved with the decoupling and preaveraging approximations to derive analytical expressions of nonlinear rheological properties and the end-to-end stretch ratio under steady shear and extension. The expressions explicitly included nonequilibrium parameters r κ , r ζ , and r B defined as the ratios of κ, ζ, and B under flow to those at equilibrium, thereby offering a method of evaluating each of r κ , r ζ , and r B from rheological and structural data under flow within the framework of those approximations. Data of extensional viscosity η E and the relaxation rate of the tensile stress decay coefficient η̇E − reported for the unentangled polystyrene melt (PS-27k; M = 27.1 × 10 3 ) and data of shear viscosity η and the first normal stress difference coefficient Ψ 1 reported for the PS-14k melt (M = 13.7 × 10 3 ) were analyzed with this method to evaluate the r ζ /r κ ratio under respective flow conditions. The r ζ /r κ ratios thus obtained under extension and shear were found to exhibit the same dependence on the Weissenberg number Wi, given that Wi was reduced to an iso-local stretch state wherein the local elastic unit of the chain (Rouse spring) is stretched to the same extent under extension and shear. The analytical expressions of the rheological properties also enabled a preliminary test of the behavior of r B . This test, made for the η E , ηĖ − , η, and Ψ 1 data mentioned above, posed a serious question about the relationships under fast flow often assumed in molecular models, r B = r ζ (proportionality between B and ζ not affected by flow) and r B = 1 (no flow effect on B).

For a type-A Rouse chain, a recent study derived an analytical expression of its dielectric loss εʺ under steady shear in terms of the basic Rouse parameters, the spring strength κ, the friction coefficient ζ, and the mean-square Brownian force intensity B, all being allowed to arbitrarily change with the Weissenberg number Wi (= shear rate multiplied by the longest relaxation time at equilibrium) and the latter two having a tensorial form; see Sato et al., Nihon Reoroji Gakkaishi, 50, 253 (2022). As a follow up, we have conducted a rheo-dielectric test for a type-A unentangled melt, poly(butylene oxide) with the molecular weight of 16 × 10 3 , to measure ε y ʺ in the velocity gradient (y) direction as well as the viscosity η and the first normal stress difference coefficient Ψ 1 . Both dielectric relaxation time and intensity were found to decrease on an increase of Wi up to the onset of rheological nonlinearity (Wi ~ 1) where η and Ψ 1 exhibited moderate thinning, but the dielectric relaxation mode distribution was not affected by this increase of Wi. Analyzing those ε y ʺ, η, and Ψ 1 data on the basis of the above expressions, we found that κ increases moderately (by ~ 40 %) but the off-diagonal components of ζ remains negligibly small on that increase of Wi. We also found that the diagonal components ζ xx (with x being the velocity direction) and B yy hardly change but ζ yy decreases moderately (by ~ 20 %). These results, suggesting the onset of the finite extensive nonlinear elasticity as well as a violation of a relationship B yy ∝ ζ yy (naively expected from the fluctuation-dissipation theorem), serves as a good starting point for deeper investigation of κ, ζ, and B.

Detachment of secondary dendrite arms has been observed in succinonitrile-camphor alloys under the microscope. The dendrites have been grown under a positive temperature gradient (columnar growth). After the tip has reached the thermocouple the displacement of the specimen was inversed and the remelting behaviour observed. It is found that detachment of arms is more frequent in concentrated alloys, when the growth rate is high and the melting rate low.

The optical system of the snow-particle counter (SPC), which was developed by Schmidt in 1977, has been improved. A laser diode is used as a light source, achieving uniform sensitivity to a blowing snow particle regardless of the location of particle trajectory within a sampling volume. The light entering a slit, which may be affected by a blowing snow particle, is perfectly detected by use of a pIano-cylindrical lens and a dual-type photodiode. A signal processor has been developed to get output voltage proportional to the mass flux of blowing snow.From the estimates based on blowing snow characteristics and wind speed profile, the new SPC system can accurately detect all the particles of effective sizes at least at a height above 0.1 m when the wind speed at a height of 1 m is less than 15 ms-I .Considering the Fraunhofer diffraction by both the wire and the particle, the relation between a particle diameter and sensor output of the new SPC system is derived from the calibration with spinning wires.Mass flux obtained with the new SPC system was found to be close to that with a snow trap. The system was operated continuously for at least nine days using two 35 A h lead batteries.

The concept of a cold air 'Parcel' is introduced for describing the bulk properties of drainage flow. By means of a model based on the momentum and sensible heat transports under calm conditions, the thickness h and velocity u of the Parcel are derived in simple forms. It is shown that h and u correspond to the inversion height and maximum velocity of actual drainage flow. The governing parameters for h and u are the length and vertical drop of the slope, potential temperature difference between the ambient atmosphere and the Parcel, aerodynamic condition of the slope surface expressed by the mean bulk coefficients, and ambient stability. The mean bulk coefficients depend on the roughness lengths for the velocity and potential temperature profiles and are decreasing functions of the slope length.The Parcel Model agrees qualitatively with Manins and Sawford's (1979) model under neutral ambient stratification. But agreement is not so good under stable conditions. The thickness and velocity of drainage ROW predicted by the Parcel Model agree with observations on slopes several tens of meters to several hundred kilometers long.

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