The solubility of iodine in PDS (polydimethylsiloxane) has been measured for varying degrees of polymerization (number of silicon atoms) from 2 to 470. The data obtained show good agreement with a solubility equation derived on the basis of the following two assumptions : (1) a PDS molecule is composed of several completely freely oriented segments, and (2) the mixture of these segments and iodine can be treated as a regular solution as far as enthalpy calculation is concerned.
A constant segment solubility parameter δ_S, which is about 7.5 cal^1/2/cm^3/2, is obtained regardless of degree of polymerization by the use of this solubility equation. This value is nearly the same as that of silicon rubber from swelling data. On the basis of the discussions above, it is concluded that the size of a segment is nearly equal to that of a siloxane unit. The molecular-attraction constant for a siloxane unit is found to be 580-600 cal^1/2•cm^3/2/mol.

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This work is concerned with the diffusivity in polymeric two-component systems in which the penetrant concentration is infinitely dilute. In polymeric systems the Wilke-Chang equation does not hold, and diffusivity shows an anomalous behavior; that is, it shows a constant value regardless of medium molecular weight. This anomaly is accounted for in this work.
The diffusivity of non-polymeric and polymeric molecules through a polymeric medium has been derived theoretically as an extension of the free-volume theory by Bueche. With this formulation, a simple expression has been developed to correlate diffusivity, viscosity, temperature and molecular weight of the system. Good agreement with the experimental data for the polydimethylsiloxane system is obtained. It is found that Dη/T is proportional to M^3.5 for the range of M>M_b, and to M for the range of M<M_b, where M is the molecular weight of polymeric medium and M_b, is a characteristic value.

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The van der Waals one-fluid theory was applied to mixtures of simple molecules and to systems containing carbon dioxide.
The excess properties of mixtures of simple molecules, G^E, H^E and V^E, were well correlated by introducing correction factors, ζ₁₂ and η₁₂, for the Lorentz-Berthelot rules for the potential parameters between unlike molecules. Further, these parameters were useful in correlating the vapor-liquid equilibria for mixtures of simple molecules.
Among systems containing carbon dioxide, the vapor-liquid equilibria for carbon dioxide-light hydrocarbon systems and carbon dioxide-fluorocarbon systems were also well correlated by introducing the correction factor, ζ₁₂. On the other hand, systems consisting of carbon dioxide and simple molecules could be successfully correlated by adjusting the critical temperature of the light component.

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Excess Gibbs free energies were determined for methyl acetate-benzene system at 30°, 40°, and 50°C and for methyl acetate-cyclohexane system at 35° and 40°C. Excess enthalpy of mixing data were obtained for methyl acetate-benzene system at 25° and 35°C and for methyl acetate-cyclohexane system at 25°, 35°, and 45°C. All experimental data for each system were simultaneously well correlated with the NRTL equation, whose parameters were assumed to be expressed by a linear function of temperature.

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A few new inequalities giving estimates for a drag force and so on are obtained. Furthermore, the following proposition is proved theoretically by means of the variational principles in a few special cases: The drag force on a body moving slowly with a constant velocity through a fluid with a given viscosity is smaller than the drag force on the same body moving with the same constant velocity through another fluid with higher viscosity. This proposition yields the conclusion that the Ostwald - de Waele fluid model is not so suitable for use in the analysis of the creeping flow of a polymer solution past a body.

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The mean particle velocities in horizontal pipe, vertical pipe and pipe bends made of transparent polyacrylate pipe 30.2 mm in inside diameter were investigated experimentally. The radii of curvature of the bends were 12, 24 and 48 cm, The solid particles used were glass beads which had a mean particle diameter of 0.189 cm and a density of 2.5 g/cm³. Radioactive particles were introduced as tracer and the particle velocities were determined by scintillation probes.
The particle velocities in both the straight pipes and the bends are distributed in wide ranges, because the flow path of each particle in pipe is different. The particle velocity in vertical pipe is greater than that in horizontal pipe. The particle velocities in vertical bends with horizontal approach flow are in general smaller than those in the other bends. The effect of the radius of curvature on the particle velocity comes to be larger when the mean flow rate of slurry increases.

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Paying attention to the discrepancy between available data, probably due to the uncertainty in void fraction, the entrance end effect and characteristics of the experimental method, newexperimental results were obtained for air-water flow in 65.8 and 122 mmφ. columns packed with glass spheres of six different sizes between 2.59 and 24.3 mm0.The two-phase pressure loss based on an energy (not momentum) balance was correlated in terms of Lockhart-Martinelli parameters as follows :
φ_l=1.30+1.85χ^-0.85, 0.1<χ<20
The total liquid holdup Ri was determined by weighing the excess weight of bed in operation over the dry column. The result was dependent on the specific surface area of the bed a_s and correlated by
R_l=0.40 a_s^1/3χ^0.22 (a^s in mm^-1)
The present result on total holdup was higher than available results obtained by quickclosing valve, which measured probably the operating holdup. Data of void fraction for spherical packings are appended and the differences in void fraction and its reproducibility due to packing procedure are noted.

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The frequency response of transfer coefficient to flow-rate change in laminar tube flow is studied experimentally and analytically. In the analysis, the linearized basic equation is solved both numerically and by using a similarity variable which is used in analysis of steady-state problem. In the experiment, the variations of local value and space-averaged value with respect to time are measured under two heating conditions, i.e., constant wall heat-flux and constant wall temperature.
From these results it is concluded that the similarity relation is not preserved in unsteady state and that resonance occurs in variation of transfer coefficient. This resonance point is characterized by a parameter SnPrX^2/3 which is derived from a similarity relation. In the last part of this paper, the effect of pulsating flow on the time-averaged transfer coefficient is discussed.

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The problem of solid dissolution in films of non-Newtonian pseudoplastic liquids falling over flat, cylindrical, spherical and conical surfaces is studied theoretically. The resulting Sturm-Liouville problem is solved by series expansion on a digital computer. Numerical results for the eigenvalues, eigenfunctions, expansion coefficients and average expansion coefficients are reported for power-law liquids. Semi-quantitative considerations are presented for considering the influence of fluid-stretching in the case of viscoelastic liquids.

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A simple model is proposed for mass transfer in a continuous phase around a single liquid drop. The model is based upon the assumption that the ratio of the average Sherwood number for a drop to that for its equivalent solid sphere is equal to the ratio of the local values at their front stagnation points. The available data for some binary systems are reasonably well correlated with the model, and it is theoretically more consistent than the analogical models proposed by Griffith, and Shirotsuka and Hirata which are based upon the boundary-layer analysis of the flow over a flat interface moving with a constant velocity.

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Applying the hydraulic-radius model to the flow in a packed bed, ion exchange liquidphase mass transfer is analysed and liquid-phase effective diffusivity, De'', based on the model is compared with the diffusivity, De, based on the film model. The maximum difference between these values was about 5% for the range of diffusivity ratio a>1 and 16% for a<1. Therefore, even if the value of De is used as an approximation, no significant error will appear. Furthermore, experimental results were correlated by the use of individual diffusivity for isotopic ion exchange and De'' for mutual ion exchange. These data satisfy the equation
J^*'' ={(1-ε)/ε}1/3 k^*Sc^2/3£/us=1.85Re''^-2/3, when Re''<100.

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The kinetics of photoreduction of potassium ferrioxalate in the presence of ammonium molybdate was studied at 365/6mμ. Measurements were made in a batchwise and parallel-beam reactor operated at atmospheric pressure and at room temperature. The concentrations of potassium ferrioxalate and ammonium molybdate were changed from 6.17×10^-8 to 3.45×10^-6 and from 2.94×10^-8 to 5.07×10^-6 mol/cm³, respectively. The decrease in the reaction rate can be explained by the mechanism in which addition of ammonium molybdate causes both deactivation and inner filter.
The ratio of the rate constant of deactivation, k₂, to that of the forward reaction, k₁, was 12.5 at 365/6mμ.
The effect of the inner filter accompanied by addition of a substance on conversion is negligible when the optical thickness of all absorbing substances, τ(c+μ_*), is very much smaller than 1.

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Though the oscillating reaction system has been regarded as quite peculiar, there is a possibility of induced oscillation in a flow reactor, if the system has some auto-catalytic character. When oscillating external forces are applied to the system, so-called forced oscillation or resonance can be expected. The resonant operation is presumed to change the reaction selectivity. As a practical example, microbial growth reaction is mathematically discussed. The results show that the selectivity at resonant frequency of external force is much improved over that at constant operation.

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The influence of physical transport resistances on observed rates of catalytic reactions can modify significantly the conversion, selectivity and stability of fluid-solid reactors. The modifying effects depend on reactor type and size, and, therefore, are critical in scale up from laboratory to commercial-scale equipment. Recent developments relating intrinsic kinetics to reactor performance through the use of mass and energy transfer rates are analyzed in this paper. In particular the relative importance of intrareactor, fluid-particle, and intraparticle mass and heat transfer limitations are considered for fixed-bed catalytic reactors. Criteria for establishing whether various types of transport processes seriously influence reactor performance are also included. Precautions necessary in order to obtain reliable rate data from laboratory reactors are discussed.

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Behavior of rising bubbles has been studied in fluidized beds of 21.4, 37.8 and 59.9 cm I.D. Sands of mean size 0.202 mm were fluidized by air at velocities ranging up to 25 cm/sec. Bubble frequency and volume fraction of bubbles in the beds were measured with a capacitance probe. Upward and downward forces produced by fluidization were measured with a strain gage probe. Bubble diameter and rising velocity were evaluated by analyzing the experimental results.
In the level region up to about 20 cm from the distributor, bubbles coalesced rapidly, rising along the wall of the bed. Particles flowed up along the wall and flowed down through the central portion of the bed. In the region of levels higher than about 20 cm from the distributor, the behavior of bubbles was strongly affected by the wall of the bed as the bubbles grew larger. Particles flowed down along the wall and flowed up through the central portion of the bed.

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Using vertical connected pipes of two different diameters and an electro-magnetic flow meter, an experimental method for measuring the average particle diameter of coarser solids under hydraulic conveying is presented with consideration of the slip velocity.
Experimental results show that the particle diameter thus determined is accurate enough for practical purposes except for the case of low liquid velocities.

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