The pattern of the flow state on a sieve plate can be divided into three regions according to different gas velocities. At the range of lower gas velocity, Region I, the clear liquid layer exists on the floor of the plates and moreover the cellular froth layer is formed on it. In the range of intermediate gas velocity over u_G=10 to 15cm/sec, Region II, the cellular froth layer grows up rapidly. In this region, the holdup of the gas phase in the froth layer first increases rapidly with the increase in gas velocity, reaches the maximum value and then decreases. At the range of higher gas velocity, Region III, the cellular structure is broken and the froth creates eddies as it flows. In this region, the holdup of gas phase is independent of gas velocity.
In Region I, the liquid-mixing in its direction of flow on the plate obeys diffusion mechanism and is controlled by the mixing in the clear liquid layer. In Region III, the liquid-mixing also obeys diffusion mechanism and is presumed to be caused by the eddies in the froth layer. On the contrary the liquid-mixing in Region II does not always obey diffusion mechanism because the circulation of the cellular froths in the direction of liquid flow is one of the important factors controlling the liquid-mixing.
On the other hand, gas phase is presumed to flow through the froth layer in a state close to piston flow in Region III.
The conclusions mentioned above and the theoretical relations for the concentration gradient in liquid phase on a tray which were already derived by authors are confirmed by means of the experiments of desorption of ammonia or oxygen in water by air.

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We have yet very little information as to some physical properties of dimethyl sulfoxide-water binary system. The purpose of this paper was to determine the physical properties of this system, such as refractive index, density, viscosity, surface tension, coefficient of expansion, specific heat, heat of mixing, solid-liquid equilibrium, vapor-liquid equilibrium, and the relation between diameter of bubble and diameter of drop. Dimethyl sulfoxide has an excellent affinity to water. The interaction between dimethyl sulf oxide and water was investigated by McAllisters' two body model, which has been derived to study the viscosity of binary mixtures.

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In a previous paper the author applied Asao's approximate solution to the heat transfer characteristics of rayon viscose solution to derive a more simplified relation by ignoring orders higher than the δ-term (boundary layer of temperature).
The author has assumed in this investigation that temperature distribution comes to the 2 nd degree equation of the distance from the pipe wall and that velocity distribution comes close to the 3 rd degree equation whithin the thermal boundary layer and the (n+1) th degree equation at the outside of the thermal boundary layer.
A fundamental equation has been solved by assuming that the viscosity of viscous fluid varies only with temperature and that other properties are constant.
By introducing a corrective constant approximate solutions were obtained, whose results were summarized in Table 3.
The results obtained in the present paper showed a fairly good agreement with those of other investigators in the range of 10⁴>Gz>10².

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