Mass transfer rates from single-and hemi-spheres of camphor to air stream were determined from weight loss due to sublimation.
The effect of air turbulence level and that of vibration, propagated to the sphere, on the transfer rates were investigated and reported in the paper.
The experimental conditions employed were as follows:
Diameter of sphere: 10, 15mm
Temperature of fluid: 10-30°C
Reynolds number: 1×10^-2×10⁴
Schmidt number: 2.80-2.85
From the experimental data the following results were obtained:
1) Mass transfer rates from the single sphere expressed in terms of Sherwood number follow Eq. (7) as proposed early by Frössling, only when no disturbances, such as turbulence or vibration, exist in the system.
2) Effect of turbulence on the transfer rates is obvious at high Reynolds numbers, while that of vibration is obvious at low Reynolds numbers, as shown in Figs. 7 and 6, respectively.
3) Mass flux from the wake region rather than from the forward region of the sphere is affected by these disturbances, as shown in Figs. 8 and 9.
4) Based on the boundary layer theory, Eqs. (18) and (20) are derived for local and overall transfer rates, respectively, from the forward region, and the results are compared with the observed data in Figs. 6 and 12.

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The following relations have been derived for the local and plate efficiencies in a plate column on the assumption that the back-mixing diffusivity in liquid flow on a tray and flow velocities of both phases are constant:
where
By means of the above equations, the effects of the liquid mixing, holding time and mass transfer coefficient may be predicted, and these correlations explain the results which have been obtained empirically or qualitatively by many investigators.

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Using Gaudin's probability of particle passage through an opening (a) in the screen cloth (Eq. 1), and introducing the idea of the number of trials of passages (i) covered by a particle before it is screened, the author derived a theoretical formula for the fractional recovery curve (Eq. 4).
For practical use, however, Eq. 4 may be rewritten as follows:
where,
On the assumption that the number of trials of passages made by a particle per unit length of screening (ξ) is constant over the whole screening surface, i will be equal to ξ·l, and the relationship between the separating size x0.5 (the size of a particle corresponding to r_i=0.5) and the length of screening (l) will be given by the following equation:
The values of a and ξ, therefore, will be determined by plotting x0.5 relative to.
The question of whether the above expression is valid or not may be answered by determining a series of corresponding values of l and x0.5. Some of the experimental results are shown in Figs. 4, 6 and 8. The index ξ may be used for expressing the performance of screens as compared with the corresponding ideal screening process based on the Gaudin's probability, and thus we have succeeded in obtaining a practical meassure of screening result.
Furthermore, by using the index ξ and the table of normal distribution, we may construct the fractional recovery curves as given in Figs. 5, 7 and 9.
The value of a serves as a measure of an effective opening of the screen.

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Effective thermal conductivities and wall heat transfer coefficients in packed beds were measured by various investigators and several kinds of methods for evaluating them have been suggested by them. But these methods are complicated and not easy to use. The new method which we present here is simple in principle and practicable. When the temperature profiles are presented by lnφ_r vs. Z/L in the ranges of linear correlation given by Eq. (14), the value of k_s can be obtained by using the slope of asymptote at Z/L=1 and the intercepts on the ordinate. The intercepts of asymptote and ordinate are expressed by C₁ and C₂ for r₁/r₀, r₂/r₀, respectively (Fig. 1). In case r₁/r₀=0, the ratio of C₁ to C₂ (C₀) is presented by Eq. (18). Thus by evaluating the value of C₀ from the intercepts, the value of the root a₁ can be easily calculated by means of Eq. (18), As α is equal to the slope of the line, k_s is directly evaluated from Eq. (15).

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Studies were undertaken for finding out adequate construction of the absorption refrigerating machines where LiBr sol. and water are employed as shown in Fig. 2. Some experiments and analyses led the author to derive appropriate conditions for these flow mechanisms as illustrated in Figs. 7-10, 14, 15, 18 and 20. The test machine, when operated, ran quite satisfactorily, so that these results would be useful for the designing of refrigerating machines or other similar chemical apparatus.

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