(1) Time required for carrying outcomplete mixing was observed of high viscous liquidis various types of mixing impellers. The most homogeneous and speedy mixing was obtained by the use of either of the commonly employed mixers, a ribbon mixer or a screw mixer having a draft tube.
(2) In such case, time required for carrying out complete mixing was inversely proportional to the impeller speed, and independent both of liquid viscosity and vessel diameter. In general, complete mixing was mostly attained in three circulations of the liquid.
In order to operate various sizes of vessels at the same mixing velocity, geometrically similar impellers should be used and rotated at the equal speed.
(3) Number of revolution of a mixing impeller required for carrying out complete mixing and that required for one circulation of liquid remained constant, independent of the impeller speed.
(4) Mixing energy was proportional to the liquid viscosity and increased proportionally with the mixing speed.
(5) Simplified explanations are given to these experimental results.

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It was observed that mass transfer was greater in a pulsation flow than in a steady flow.
As one of the simplest cases of mass transfer in a pulsation flow, we studied mass transfer through an inside tube wall to a pulsation flow, using a sample tube, whose inside wall was coated with β-naphthol. An experimental apparatus as shown in Fig. 1 was employed for the analyses of the systems. A piston type pulse generator was used for determining relationships between mass transfer and pulsation characteristics in the pulsation flow caused by superposing the "sine waveflow" on the steady flow.
Experimental conditions were as follows
(a) Flow condition; Apparent Re. number: 500-10, 000
(b) Pulsation characteristics:
Frequcncy: 100-500(cycle/min)
Linear amplitude for l cycle: 0-2.0×10-¹(m)
(c) Dimensions of sample tube
Length: 0.3(m)
Inside diameter: 1x10-²(m)
The mass-transfer Coefficient k_L(kg-mol/m²·hr·kg.mol/m³) and JD-factor were obtained from the experimental results, and are shown in Table l and Figs. 4 and 5.
Conclusions:
(1) Mass-transfer coefficient increases in direct proportion to the increase of amplitude and frequency, but in inverse proportion to that of Re. number.
(2) The following equation represents the rate J_D-factor increase, (J_p-J₈/J₈)D, as obtained by the dimensional analysis.
(3) It is supposed that the charactristic increment of mass transfer in the pulsation increase in turbulency, affecting such flow conditions as frequency and amplitude.

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A method is presented for the evaluation of rheological material constants of Bingham bodiesby means of Couette Apparatus. The method previously proposed by M. Reiner and R. Riwlin holds only when, but the method proposed here applies not only when but also when.
Let
(11)
(12)
M: moment induced when the outer cylinder is rotated [Kg·m]
N: number of revolutions of the outer cylinder per minute [1/min]
By measuring the moments induced at two different revolutions of the outer cylinder, sufficient data are obtained from which to derive the characteristic constants.
For two pairs of M and N the following equations are introduced:
(21)
(23)
where,
when
(15)
and when
(16)
Relation among a, d and r was calculated previously, so that a_l, a₂, r₁ and r₂ can easily be obtained from Fig. 2 or a-d-r Table by means of a simple trial-and-error procedure. When a_l and r_l arc known, yield value τ_y and plastic viscosity ηcan be calculated by the following equalions.
(24)
(25)
The above-mentioned trial-and-error procedure is one of the methods most commonly employed for the evaluation of two plastic constants; besides this, a direct method may be recommended as an expedient, provided that the following equations hold.
(37)
(35)
(36)

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All the conventional continuous vacuum filters are of complicated constructions because of their blow-back mechanism.
In their experiments with starch mi1k, the authors found that the continuous vacuum filtra lion could successfully be carried out under a blowless condition, aad supposed that perhaps there were many varietie3 0f slurries which might be treated under the same condition, viz., with no blow-back air employed.
When no blow-back air is employed, the cakeis more highly dehydrated, and can easily be stripped off, block by block, from the surface of the filter, by a mere contact of a doctor.
In this paper is introduced a simplified type of a continuous vacuumf ilter, "O-S Filter, "as shown in Fig. 1, with several suggestions for its construction design.
For designing vertical tubes used for discharging filtrate by means of vacuum-air lift, where exhaust air is employed, some basic experimental studies were conducted. The results of these experiments are presehted in Fig. 6 & 7, together with a design of a suction tube.

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