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The use of the Reynolds flux to assess momentum transfer and pressure drop behaviour in condensation was a basic idea of a paper by Silver (1)†. In the present paper the same concepts are used with more consistent logic to develop a simpler and more satisfactory treatment. Experimental results of velocity profile measurements show that the assumptions made are permissible. The predictions from the improved theory are generally in accord with those previously given by Silver (1) and now confirmed by Wallis in the first of these two papers.

Reacting urea formaldehyde condensation products with triethanolamine, sodium hydrosulfite and monochloroacetic acid respectively, urea resins for wet strength paper are produced. The ratio of the modifiers to urea is 0.1 : 1 or 0.2 : 1. For triethanolamine or sodium hydrosulfite, the reactions are carried out at 90°C and for monochloroacetic acid, at 100°C. The reaction times are determined according to “ Alum test ”. For the better preservation of these resin solutions, the solid content must preferably be higher than 10%. Although the urea resin is cured more slowly than melamine resin, the difference of the wet strengths of the papers treated with these resin is hardly found after 10 days.

The paraelectric-to-ferroelectric phase transformation of (NH 4 ) 2 Cd 2 (SO 4 ) 3 is conjectured to be caused by an instability of three degenerate pairs of conjugate lattice vibration modes with a wave length such that the condensation of each pair of conjugate waves should triple the primitive unit cell. This was explained in a previous paper with a model in which the spontaneous polarization vector arises parallel to the wave normal of the condensed soft waves. Reality of this model, however, seems difficult because of a certain severe requirement for its ferroelectricity. The present paper proposes a model in which P s arises perpendicular to the wave normal. This model implies no such severe requirement.

This paper deals with the generation and the movement of the liquid phase in the last stages of large condensing steam turbines. Considering thermodynamic instability, the primary droplet size resulting from spontaneous condensation is dependent on radial position, the flow, and inlet parameters. The analysis of the liquid phase transport to the blade surface is given, and the stability and disintegration of the liquid films on the blade surface is discussed.

Summary The paper-electrophoresis of the c-s-f-proteins was performed in 18 cases of schizophrenic pateints. In order to obtain enough condensation of the c-s-f, the dialysing concentration for the polyvinylpyrrolidone solution was used, and the electrophoresis was performed according to Gvassiitnnn and Haniaig's method.

This paper presents the results of measurements to determine the average size and number of droplets which appear during spontaneous condensation of expanding undercooled steam. The measurements were carried out in a non-symmetric convergent–divergent nozzle for three expansion rates, , of 2000, 5000, and 8000 units per second, and pressure in the Wilson region of 0·4–1·5 bar. The method is based on the measurement of monochromatic light beam intensity attenuation when passing through a layer of wet steam of length l (width of the nozzle) and static pressure variation through the nozzle axis. The photometric method was verified by measuring the droplet sizes in sulphur emulsion. The average size and number of droplets during spontaneous condensation were found to be dependent on the expansion rate and pressure in the Wilson region, and the results of the measurement are in qualitative agreement with those obtained by Gyarmathy. The average droplet size measured by the photometric method is about 25–60 per cent greater than the corresponding values of Gyarmathy. The droplet size measuring error, determined by an approximate analysis, was found to be in the range 15–30 per cent.

This article considers methods of calculating condensation processes in wet steam turbines. Equations are given for determining the rate of nucleation, the growth of droplets, and the wet steam parameters. The condensation processes within the blade ring of a steam turbine are used by way of example. It is made clear that the condensation process is continuous at large enthalpy gradients. Under these conditions the theory of discontinuous condensation will not represent the actual process. Calculations based on the kinetic theory of phase change agree well with experimental findings. The constructional features of the blading which operates within the Wilson zone can have a considerable effect on the extent of the undercooling and on the size of the droplets. The trajectories of the droplets in the space between blade rings can be determined using standard approximate equations. The Coriolis force has a considerable influence on the motion of the entrained liquid within the moving blades. Under the influence of this force the liquid may move either with the flow or against it.

1. The relation between the measured absorption at Hγand absolute magnitude was made for A stars (B8–A3) in 1950 and for B stars in 1953. The systems so obtained gave lower luminosities than the MK calibration and the more recently derived photometric-distance scale. Furthermore, the rise of photo-electric three-colour photometry has recently made available accurate magnitudes and colour excesses of a substantial number of early-type stars in the nearer open clusters. A reconsideration of the Hγ–Mrelation then appeared to be feasible and worth while.

A simple theory is presented for laminar film condensation of a pure vapour on a vertical surface which takes account of the drag induced on the liquid film by the flow of the condensing vapour. Experiments were carried out with steam at atmospheric pressure condensing inside a vertical 1.824 in diameter tube 8 in high. The downward vapour velocity was varied from 5 to 150 ft/s, the corresponding range of the film Reynolds number at the bottom of the tube being 200-500. Experimental results agreed well with the theory.

The data shown by Berg [Berg and George, 1968] for droplet size as a function of time appear, at least in the region of greatest frequency of measurements, to be quite reasonable. The quasi-static diffusional growth theory [Schuster, 1967] yields a time dependence of radius r which goes as where the initial size is considered negligible and a sticking coefficient of unity is employed. Here, P is the vapor pressure of water at temperature T, 1 + € is the expansion ratio of the cloud chamber, S is the supersaturation, L is the latest heat of condensation, Kc is the coefficient of thermal conductivity, t is the time, and a, b, and c are constants. During an expansion, ϵ is a function of time, and hence T, P, and S are also time-dependent. The quantities L and Kc also depend on time through their temperature dependence. S − 1 is the only quantity that is first-order time-dependent and, therefore, changes rapidly.