Pressure loss and collection efficiency of the impinger dust sampler were experimentally studied by using the apparatus of Fig. 1. Two kinds of test powders used in the experiment were as shown in Table 1. The results may be summarized as follows:
1. Pressure loss of the impinger is generally a little bigger than liquid head plus kinetic velocity head about the nozzle. (Figs. 3 & 4)
2. Collection efficiency of the impinger depends on the liquid level as well as on the gas velocity at the nozzle. Better results are obtained when the gas velocity at the nozzle is over 100m/s, and the liquid height is greater than 40mm over the nozzle. (Figs. 5, 6, 7, & 8) On the whole, in spite of its rather big pressure loss, the impinger had good collection efficiency even for carbon black particles. Further, a method was discussed for estimating an approximate collection efficiency (by collision) of a dry impinger.

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Absorption of carbon dioxide by monoethanolamine solutions was studied using packed columns, at atmospheric and elevated pressures. Based on the data obtained, the overall mass transfer coefficient relative to the gas composition and the height of the overall transfer unit were calculated from the following equations:
[kg moles/m³ hr atm]
[m]
(1) The effects of various factors on KGa, at atmospheric pressure, when CO₂ concentration in the as was high, were made clear, and with these effects, the data on the 3kg/cmcm2g pressure column operated in conjunction with a regeneration column were correlated. As the result the following empirical equation was derived for 5mole/l monoethanolamine solutions.
KGa=20.1e-(1170/T+1.56pav+3.68xav).L0.60
Thus, KGa was found to be independent of G and its values to be lower than those obtained from the Kohl's correlation.
(2) When CO₂ concentration was low and high degree of purification was attained to, the values of KGa increased in direct proportion to G and were independent of L. Accordingly, in the ranges covered by the present study, the values of HOG obtained were constant, as follows:
For 2″ column at the pressure of 3kg/cm²g, HOG=0.25m
For 90mm column at the pressure of 20kg/cm²g, HOG=0.30m
From these results it may be concluded that at high concentration of CO₂, the liquid film resistance is controlling and at very low concentration, the gas film is controlling.

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The authors investigated the variation of crushing mechanism of a ball mill relative to mill speed, and found that crushing mechanism of the mill at 70 per cent of the critical speed was mainly represented by the impact compression. Whereupon they applied Eqs. (2)-(7)-relation between the crushing condition and the net work input to crushing by impact compression-to the ball mill crushing. By these Eqs., the authors' assumption on the effect of density, size and drop height of the ball on the capacity of the mill were proved to be nearly in accord with the expcrimental results.
(a) The relation of the ball load to the capacity of the mill at the normal speed, i.c., 70 per cent of the critical speed, might be expressed by Eqs. (10)-(14). In case the total ball load is proportional to the weight of one ball at constant specific weight and constant number of balls, the relation is given by Eq. (10), but, when the ball load is proportional to the number of balls at constant specific weight and constant ball size, it is given by Eq. (11). On the other hand, in case the ball load is proportional to the specific weight at constant size and number of balls, it is given by Eq. (14).
(b) The relation of the mill diameter to the capacity may be expressed by Eqs. (16) and (17). Of the two mills, having equal ball charge rate to the mill volume, but different diameters, the mill with the larger diameter has greater efficiency. So does the mill having the balls of smaller specific weight.

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Crushing of powdery materials (stone ware and hard chalk) was accomplished with a drop hammer. The impact resistance force P produced was measured with a wire-strain-gage dynamometer and a Brown-tube oscilloscope, and the total deformation of the packed sample, with a photoelectric tube or a depth gage. From these results were obtained P-δ curve for various samples relative to loading conditions. (Fig. 12-15).
Graphical integration of P-δ curve gave the actual work Ur and further the relation between Ur and A or η and A, where A is the gross energy input and η is the efficiency of the energy. (η=Ur/ A×100%) (Fig. 16.-Fig. 19, Fig. 20 is a schematic representation). These data are classified into two groups. In the first group, the gross energy input A, and in the second group, the drop weight or the drop height, is a regulating factor. The former case is likely to happen when the pile height is small, when the penetration of stress is perfect throughout the sample and when solidification of powder occurs. And the latter, which is the most general of all the crushing conditions, often happens when the pile height is big and the penetration of the stress is not uniform.
Lastly, by comparing the actual work Ur with the resultant crushed product D, the authors obtained an almost linear relations between them.

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