The effect of migration on the limiting current was analyzed by use of the numerical method. The analysis was conducted for two cases, the transient current at a cylindrical electrode and the steady current at a rotating disk electrode. The result of the present analysis for the rotating disk electrode was compared with the approximate analysis of Gordon et al., where the former showed a greater migration effect than the latter. The diffusivities of ferricyanide and ferrocyanide ions in dilute solution with KOH supporting electrolyte were measured by both the unsteady-state and the steady-state methods at 30°C. The concentrations of Fe(CN)₆^3- and Fe(CN)₆^4- were 0.02 to 0.2 kmol/m³, and that of KOH was constant at 1.0 kmol/m³. The diffusivities obtained from both methods coincided well with each other, and also with the available results by many other investigators for equimolar ferricyanide and ferrocyanide ion solutions.

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The flow transition from uniform bubbling regime to liquid circulation regime was studied in a vertical two-dimensional bubble column with no net liquid flow. A regular two-loop liquid circulation was observed to occur as a result of violent interactions of unsteady liquid circulation and large bubbles. A critical superficial gas velocity was defined as the velocity at the point of incipient regular circulation and was obtained from the gas velocity at maximum gas hold-up. Under a uniform stable gas distribution the critical gas velocity depends on the ungassed liquid height and is independent of sparger geometry, i.e., the diameter and pitch of holes. When the pressure drop through the sparger is insufficient or inlet gas is distributed in the narrow central region of the sparger, interactions of large-scale liquid motions and large bubbles in the bulk section is suppressed by depleting the growth of large bubbles at the base. This makes the critical gas velocity larger than that under the uniformly sparged condition.
A similar dependence of critical gas velocity on ungassed liquid height was confirmed with literature data for three-dimensional bubble columns.

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Effect of wettability on static drop formation cycle from a hole in a horizontal flat plate into air was studied experimentally and theoretically. Water, glycerin, kerosene and liquid paraffin were used as the liquid in the experiments, and copper, Teflon, acrylic resin and glass were used as the solid.
The experimental results are classified into the following three cases. 1) Case 1, where the contact line, defined as the boundary among the three phases, is fixed. 2) Case 2, where the contact line is free to move. 3) Case 3, where the liquid wets the solid perfectly.
It is found that the important factor governing the maximum stable drop volume V_max is Bond number for Case 1, and is advancing contact angle for Case 2. A method of predicting V_max in each case is proposed. It is revealed that the drop formation cycle for the three cases can be simulated theoretically by solving the variational problem which is derived from analysis of the potential energy of drops, using the finite element method.

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Wet particles of activated alumina were dried in batch and continuous packed fluidized beds with open-end cylindrical screen packings. The drying characteristics of the packed fluidized bed dryers was investigated.
The drying rate in the constant drying rate period can be estimated by the empirical equation for gas-particle heat transfer coefficient obtained by Kato et al.¹⁾, and the drying rate in the falling drying rate period is proportional to the free moisture content in the particles. Both overall drying rate in the continuous packed fluidized bed dryer and outlet gas temperature from the bed were affected by superficial gas velocity, bed height, inlet gas temperature, average residence time of particles in the bed and packing size.
The drying characteristics of a continuous packed fluidized bed dryer is analyzed by the plug flow model for the gas flow pattern and the plug flow model or the perfect mixing model for the particle flow pattern in the bed.
If the packing size is smaller than 2.5 cm, and the average residence time of particles is less than 30 minutes, the drying characteristics in the bed can be analyzed by the plug flow model for the particle flow pattern in the bed and the plug flow model for the gas flow pattern.

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The rates of absorption of pure oxygen into aqueous cuprous chloride solutions containing hydrochloric acid were measured at atmospheric pressure and at 15°, 25° and 35°C using a baffled agitated vessel operated batchwise with a flat gas-liquid interface. The experimental results were analyzed by the chemical absorption theory based on the Lévêque model. The measured absorption rates were in good agreement with the theoretical predictions.

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A hydrogenation reactor with palladium as a catalytic membrane permeated by hydrogen was designed and the mechanism of the hydrogenation of ethylene was analyzed.
It was demonstrated by experiment that, where the resistance of mass transfer in the gas film can be neglected, the range of ethylene partial pressure was distinctly separated into two domains: one domain where the overall reaction rate is approximately proportional to the ethylene partial pressure and another where the overall rate is equal to the permeation rate of hydrogen into vacuum at constant hydrogen pressure.
The analysis demonstrated that the two domains correspond to the chemical reaction limitation and the limitation of hydrogen diffusion through the membrane, respectively. It was also demonstrated that the distinct separation of the domains is due to the large value of k₀/k_i, , which is the ratio of the rate constants of hydrogen dissolution into and out of the palladium membrane.
In addition, it was demonstrated that the permeatation rate is scarcely affected by a change in reaction rate under a certain condition. This was in good agreement with the experimental results.

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Kinetic studies on the self-decomposition of ozone in water, the decomposition of CN^- and CNO^-, and the decolorization of several dyes by ozone were performed over a wide range of pH using a stopped-flow apparatus under homogeneous conditions at 298 K. The rate of selfdecomposition of ozone was measured in the pH range from 1 to 13.5, and it was found that in the pH range above 8 the rate was expressed by
-d[0₃]/dt=314 [0₃] [OH^-]^0.88
while in the acidic region the concentration dependence of the rate was complicated, and a simple rate expression could not be obtained.
The rate of decomposition of CN^- by ozone was expressed by
-d[CN^-]/dt=310 [O₃]^0.8 [CN^-]^0.55 (9.4<pH<11.6)
and the rate of decomposition of CNO^- was found to be much slower than that of CN^-. The decolorization rates of naphthol yellow and methylene blue followed second-order kinetics. Rate constants are presented.

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The sulfurization of sintered reduced iron in a hydrogen gas stream containing hydrogen sulfide was investigated. To describe the behavior of this reaction system accompanied by significant decrease in porosity of reacting solid, the volume reaction model was modified in due consideration of the variation of effective diffusivity. Observed overall reaction rate under the influence of diffusion limitation was well represented by this model. The intrinsic rate constant was then separated from the overall rate data and correlated in an Arrhenius-type equation. The rate process is also discussed in detail in relation to the shrinking core model and the accuarcy of its application is dealt with.

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A series of experiments were performed on infrared laser beam absorption (multiphoton absorption) and subsequent dissociation (multiphoton dissociation) of CF₃Cl to propose models for the design of reactors for isotope separation by lasers. A parallel beam geometry was utilized in batch irradiation experiments to make direct compilation of lumped-parameter data possible.
Multiphoton absorption is found to be expressed by a power-law extension of the law of Lambert and by an addition of a new term for buffer gas effect to the law of Beer.
For reaction analysis, a method to evaluate the effect of incomplete mixing on apparent reaction rates is first presented. Secondly, multiphoton dissociation of CF₃Cl is found to occur in pseudofirst order fashion and the specific reaction rates for different beam fluence are shown to be correlated to the absorbed energy.

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The UV inactivation of Bacillus subtilis spores, widely used for examining sterility, was kinetically studied to obtain fundamental information on the design and performance evaluation of practical sterilizers irradiated by ultraviolet rays.
The inactivation rate at low extent of sterilization (survival fraction of more than 10^-2) was determined under monochromatic irradiation and analyzed by the single-hit-killing model based on the target theory. The inactivation cross-section, φa, was strongly dependent on wavelength; the target number, m, was rather constant from 240 through 300 nm.
The inactivation characteristics at high extent of conversion (survival fraction of less than 10^-3) under polychromatic irradiation were simulated by considering the presence of a small portion of UV-resistant spores. An improved kinetic model was derived on the assumption of coexistence of two types of spores with different inactivation cross-sections and with the same target number. The observed wavelength-averaged inactivation cross-section for the major portion of spores was evaluated from both the inactivation cross-section obtained with monochromatic irradiation and the spectral distribution of light emitted from a polychromatic lamp.

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Theoretical and experimental studies were conducted on the UV-inactivation characteristics of Bacillus subtilis spores in an annular-flow sterilizer irradiated by a germicidal lamp located at the center of the inner tube.
Experimental results for sterilizer performance in laminar spore-suspension flow were well simulated dynamically and statically by theoretical considerations which incorporated multi-targets with single-hit model for the UV-inactivation kinetic and the diffuse light model for the angle characteristic of lamp, along with due attention to the parabolic velocity distribution and the negligible diffusion of spores. Scale on the outside wall of the inner tube was checked by the use of a cylindrical chemical actinometer.
Calculated examples elucidate the reason why careful inspection is needed of UV-inactivation kinetics, angle characteristics of lamp, and fluid mixing to evaluate performance of actual flow UV sterilizers at high extent of inactivation up to the order of 99.999 %.

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