From the viewpoint of the surface renewal theory or the film penetration theory, mass transfer in a liquid film was considered.
The theoretical equation (6) based on the surface renewal theory was derived by assuming that the surface age distribution should change with contact time and moreover that the liquid surface is renewed by the liquid at zero concentration.
Secondly, the theoretical equation (7) based on the film penetration theory was derived by assuming the presence of a region where unsteady molecular diffusion is controlling, which led to the assumption that the concentration of the bulk of liquid increases with contact time.
As shown in Figs. 3-8, these theoretical equations are compared with experimental results of CO₂ absorption in water.
Eq. 6 agrees well with the data at Γ=1.9 and 0.9g/cm·s, but deviates from the data in the case of lower flow rates. This disagreement is due to the fact that at the lower flow rates there occurs a considerably larger concentration of the liquid bulk and therefore the newly-formed surface is not necessarily replaced by the liquid at zero concentration.
Eq. 7 agrees with the data over a wide range of flow rates as compared with other equation.

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In order to evaluate the range of experimental error originated in the heat loss from the edges of the plate in the twin-method for thermal conductivity measurements, the experiments were made under various conditions.
Considering the edge effect, a differential equation was derived and solved, which solution was compared with the experimental data with fairly good coincidence.

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A new design method of a solid-gas two phase flowmeter is developed to measure the flow rates of each phase simultaneously. This flowmeter consists of both a diverging tube and a straight pipe section. The flow rate of air can be measured at the diverging tube and the solid-gas mixture ratio can be obtained from the pressure differences both at the diverging tube and the straight pipe section. All the parameters in these relations can be calculated theoretically. The solid-gas two phase flowmeter is constructed based on the above results and its practical utility is verified by experiments.

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An experimental investigation has been made of the pressure drop and efficiency characteristics of a rotary dust collector with a tangential inlet. This collector is of the peculiar cyclone type equipped with a rotor. operating at inlet-air velocities below 10m/sec and rotational speeds of up to 1, 500 r.p.m. Fly ashes were used as dust materials.
The results indicate that the pressure drop through the collector is correlated as a function of the operating variables, almost independent of the dust loading of the air handled. It is also shown that the prime factor affecting collection efficiency is the peripheral speed of the rotor, and that the geometric variables other than rotor diameter have little influence on both pressure drop and collection efficiency for the conditions studied.
Comparisons are presented among three different types of rotors, and recommendations are made for the efficient and pertinent type in practice.

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