The influence of fluid elasticity on wall effects for creeping sphere motion in cylindrical tubes

Experimental results are presented of wall effect for the slow motion of spheres in elastic, constant-viscosity liquids. The results are correlated in terms of diameter ratio for d/D < 0.3, and Weissenberg number We < 5. Weissenberg number is defined as We = 2θV_m/d, with θ the Maxwellian relaxation time (θ = N₁/2τγ). The wall effect is found to be adequately described by Newtonian expressions for small Weissenberg number, We < 0.01. For larger values of the Weissenberg number, We > 0.2, virtually no wall effect is discernible; the small effect observed is correlated by the wall factor expression The wall effect observed is ascribed to the influence of fluid elasticity alone, since all the fluids used were elastic to a greater or lesser extent, but showed no shear thinning.      

The Crystal and Molecular Structure of Ethyl p-Chloro α-Cyano-β-Methyl-Cis-Cinnamate,C13H12No2Cl

Crystals of ethyl p-chloro α-cyano-β-methyl-cis-cinnamate, C₁₃H₁₂NO₂Cl, are orthorhombic, space group Pbcn, with eight molecules per unit cell, a = 17.31, b = 8.68 and c = 17.20 Å. The structure was solved by direct methods and refined subsequently by Fourier techniques. The benzene ring makes a dihedral angle of 60.0° with the ethylenic group. This suggests significant steric effects of the β-methyl group and of the carbonyl group on the orientation of the benzene ring. The conformation of the ethylene bond and the carbonyl group around the C_α? C bond is roughly cisoid and the angle of twist is 16.5°. Nearest-neighbour >C = C <groups make contact across a two-fold axis at a center-to-center distance of 4.33 Å.     

Volatilization of components from zirconia ceramics

Conclusions We investigated volatilization in isothermal conditions of solid solutions of oxides of calcium and yttrium in ZrO₂.The calcium oxide is intensely sublimited from the solid solution of zirconium dioxide, stabilized with CaO at 2000–2100°C. However, during soaking and rapid cooling, destabilization does not occur, even during sublimation of 70–75% CaO. With rise in temperature to 2400–2500°C and a 4 h soak, only 0.5% CaO is preserved in the solid solution, which leads to destabilization and conversion of a large part of the cubic form of ZrO₂ with calcium oxide by fusion, we note sublimation of part of the CaO, and the remaining quantity (3%) is adequate for complete conversion of the zirconia into the stable cubic form.Volatilization of the stabilizing additive occurs in the form of YO at substantially higher temperatures than volatilization of the calcium oxide from the solid solution of zirconium dioxide, stabilized with yttrium oxide. Simultaneously with this we note volatilization of zirconium dioxide in the form of ZrO and ZrO₂.For the use of zirconium dioxide at elevated service temperatures, we would recommend yttrium oxide as a stabilizing additive.Translated from Ogneupory, No. 1, pp. 49–52, January, 1968.     

Algal phagostimulants for marine herbivorous gastropods

Methanol extracts of the green algaUlva pertusa contain four kinds of glycerolipids that are active as feeding-stimulants for marine herbivorous gastropods. These compounds are digalactosyldiacylglycerol (DGDG), 1,2-diacylglycerly-4-O-(N,N,N-trimethyl)-homoserine (DGTH), 1-monoacylglyceryl-4'-O-(N,N,N-trimethyl)-homoserine (MGTH), and 6-sulfoquinovosyldiacylglycerol (SQDG). The various gastropods exhibit marked specificity, however, as young abaloneHaliotis discus respond to DGDG and DGTH at minute dosages of 20–30 g/sample zone, but do not respond to 300 g of SQDG, which is a phagostimulant for two other kinds of gastropods,Turbo comutus andOmphalius pfeifferi.Chemical Studies on Phagostimulants for Marine Gastropods. Part VI. For Part V, see Sakata et al. (1986b).     

Direct Observation of Triplet Reactions of Anthraquinone Vat Dyes Using Nanosecond Laser Photolysis

The triplet-triplet spectra of three commercial anthraquinone vat dyes (C.I. 67300, C.I. 59100 and C.I. 60515) were studied in solution at room temperature using laser photolysis. The triplet states of these dyes react with oxygen, and the rate constants for the quenching process were measured, together with the rates of energy transfer from the triplet state to anthracene. These observations are considered in relation to the photoreactivity of these dyes.     

A thermomechanical investigation of highly cold-drawn polycarbonate

A new technique detecting molecular motions in drawn polymers was applied to highly cold-drawn polycarbonate of bisphenol A. It is shown that the sample exhibits thermal shrinkage in three steps with the temperature increase up to above the glass transition temperature. The molecular relaxation at the highest temperature is due to the glass transition. The other two molecular motions at the lower temperature are those of main chain in the glassy state and they correspond to the molecular motions as revealed in dielectric measurement by Sacher.¹ By using the general theory of the thermal analysis by Ozawa,² the apparent activation energies of these molecular motions were obtained: for the highest temperature 110 kcal/mole, and for the lowest temperature, 33.5 kcal/mole. The impact strength and the cold workability of this polymer are also discussed in relation to these molecular motions.     

Mullite-corundum refractories for pouring steel through slide gates

Conclusions At the Ukrainian Scientific-Research Institute of Refractories, in collaboration with Ukrogneupornerod and the Chasov-Yar Refractories Combine, methods have been developed for improving the service properties of mullite-corundum slabs and increasing their reliability and stability in operation. The commercial production of mullite-corundum slabs has been organized.The slabs are being successfully used in stopperless steel pouring at the Il'ich Metallurgical Works, Zhdanov, and at the Donetsk Metallurgical Works.To increase the stability of mullite-corundum slabs to two or three meltings, it is necessary to organize the commercial production of these articles with alumina-enriched binder.Translated from Ogneupory, No. 5, pp. 25–29, May, 1981.