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  • 1965-1969  (801)
  • 1890-1899
  • 1870-1879
  • 1967  (801)
  • Physics  (429)
  • Chemical Engineering  (312)
  • Computational Chemistry and Molecular Modeling  (60)
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  • 1965-1969  (801)
  • 1890-1899
  • 1870-1879
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  • 101
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 771-780 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The activity coefficient γNa+, of sodium ion, in aqueous solutions of both isotactic and conventional poly(methacrylic acid) (PMA) has been studies throughout the whole range of degree of neutralization α with a Beckman Na electrode and membrane electrodes. The results show that the fraction of sodium ions bound to isotactic PMA is higher than that bound to conventional (or syndiotactic) PMA over the entire range of α. The binding of divalent counterions (Mg+2, Cu+2, Co+2, and Ni+2) by the two forms of PMA (at α = 0.95) has been evaluated from the release of Na+ ions with the Beckman Na electrode. Turbidimetric determinations of the critical amount of various divalent cation chlorides necessary to bring about precipitation of both isotactic and conventional PMA (at α = 0.95) have also been carried out.
    Additional Material: 6 Ill.
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  • 102
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is possible to identify three distinct types of polymer adhesion on the basis of the physical state of adhesive and adherend: (1) rubbery polymer-rubbery polymer (R-R adhesion); (2) rubbery polymer-glassy polymer (R-G adhesion); (3) rubbery polymer-nonpolymer (R-S adhesion). Limitations of the diffusion and adsorption theories and their conflicting results are discussed within the framework of the proposed classification. By defining the physical state of the polymer as an adhesive or as an adherend, it is possible to eliminate many of the discrepancies commonly noted in attempted application of the diffusion and adsorption theories. As predicted by the Bueche-Cashin-Debye equation, the diffusion of a polymer into another should be greatly reduced as it changes from the rubbery to the glassy state. For this reason, diffusion, which depends to a great extent on the physical state of the polymer, is actually a limited, selective process. Assuming a 1013 poise bulk viscosity at glass temperature, self-diffusion constants of forty polymers were calculated to be 10-21cm.2/sec. or 10-5A.2/sec. This slow rate of diffusion is unmeasurable and insignificant. Adsorption, which is less dependent on the physical state of the polymer, is more frequently encountered.
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  • 103
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    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 957-972 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Drawing of linear polyethylene at 60°C. to an extension ratio of ten drastically reduces the sorption and diffusion of n-pentane, benzene, methylene chloride, and tetrachloroethylene. Methylene chloride was chosen for more detailed study. The sorption is of the normal Fickean type. It is also fully reversible in the temperature range between 25 and 45°C. if the sorbed amount is kept to below 0.5%. At higher concentrations the sample relaxes so that sorption irreversibly increases. The reversible sorption per gram of amorphous component is about 1/6 of that in undrawn polyethylene. The diffusion constant has a larger temperature and concentration dependence than in the undrawn material. At zero concentration the activation energy for diffusion is 34.4 kcal./mole and the diffusion constant at 25°C. is 8 × 10-11 cm.2/sec. as compared with 14.4 kcal./mole and 1.5 × 10-8 cm.2/sec. in undrawn PE. Cold drawing reduces the sorption sites without changing their energy content, but drastically cuts down diffusion and increases the activation energy. A smaller part of the increase of the latter is a consequence of the lower enthalpy of the amorphous material and a larger part is probably due to the increased distance between sorption sites.
    Additional Material: 8 Ill.
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  • 104
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1055-1059 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method of evaluating osmotic coefficients of polyelectrolyte solutions is suggested for systems in which a two-phase equilibrium is maintained between the polymer solution and a polymer precipitate so that the “polymer” terms Cpdμp in the Gibbs-Duhem relationship may be neglected. The method is applied to a polybase system, and the osmotic coefficients calculated from the experimental data are discussed in terms of the theory of Alexandrowicz. The results are found to be in line with the above theory but the characteristic parameter φp, the fraction of free counterions, is about twice as large as values previously observed in polyacids.
    Additional Material: 2 Ill.
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  • 105
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1061-1066 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Osmotic pressures of aqueous solutions of poly(diethylaminoethyl methacrylate) hydrochloride, in equilibrium with a precipitate of the un-ionized polybase, at various concentrations of polymer and NaCl in solution and at different values of pH are derived from emf measurements and the “cell” theory for polyelectrolytes. Single-ion activities are evaluated according to two procedures. The first is based on measurements with ion-specific electrodes versus a calomel electrode. The second makes use of a salt bridge, but assumes that the co-ions have activity coefficients equal to the mean activity coefficient of the salt in a polyelectrolyte-free solution of the same concentration. The results show that the calculated values of the osmotic pressures are consistent with those obtained by the exact integration of the Gibbs-Duhem relationship, when the first procedure is employed. If, however, the single-ion activities are evaluated by the second procedure, the osmotic pressures obtained are consistently lower by about 10%. These differences arise because the two methods yield different values of the activity coefficients of the single ions.
    Additional Material: 1 Ill.
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  • 106
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1079-1086 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic strain-optical coefficient of low-density polyethylene is found to decrease with increasing frequency and increase with increasing temperature (at temperatures up to 60°C.). It is found that a series of curves representing the real, K′, and imaginary, K″, parts of the frequency variation of the strain-optical coefficient obtained at various temperatures up to 60°C. may be superposed by translation along the frequency axis. The temperature dependence of the shift factor corresponds to an Arrhenius type equation with an activation energy of the order of 25 kcal./mole. This may be compared with the similar value obtained by Takayanagi for the αc′ mechanical loss and with the dynamic x-ray diffraction values reported by Kawaguchi et al., but is somewhat lower than the value of 34 kcal./mole reported by Onogi et al. from birefringence relaxation studies. Takayanagi has ascribed the αc′ peak to cooperative motion of crystalline and amorphous regions of the sort that might be involved in the suggested sliding of lamellae over each other. At temperatures higher than 80°C., horizontal superposition is not possible.
    Additional Material: 8 Ill.
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  • 107
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The time-dependent birefringence has been measured simultaneously with the stress relaxation on quenched and annealed low-density polyethylene at various temperatures from 10 to 70°C. The strain-optical coefficient increases generally with increasing time, and approaches the equilibrium value, which depends upon the temperature. When the strain-optical coefficient at a fixed time is plotted against temperature, it first increases and then decreases after passing through a maximum at Tmax with increasing temperature. The higher the degree of crystallinity, the higher are the equilibrium values of the strain-optical coefficient and Tmax. The curves for strain-optical coefficient versus time and relaxation modulus versus time below Tmax can be superposed well by a horizontal shift along the abscissa. The optical shift factor obeys the original WLF equation, while the mechanical shift factor is much larger than the optical one. The molecular mechanisms corresponding to this dispersion of the strain-optical coefficient and viscoelastic αc absorption peak near Tmax are discussed.
    Additional Material: 12 Ill.
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  • 108
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1320-1322 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 109
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1323-1325 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 110
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1329-1329 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 111
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 63-81 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Detailed structure analysis of the polyoxymethylene molecule was carried out by the method of three-dimensional Fourier synthesis. The diffraction data were measured on a highly ordered polyoxymethylene sample prepared from a single crystal of tetraoxane by solid-state radiation polymerization. By assuming the anisotropic thermal factors for the oxygen and carbon atoms and taking into account the contribution of the hydrogen atoms, good agreement between the observed and calculated structure factors was obtained; the R factor is 8.8%. The distance between the oxygen atom and the helix axis r(O) = 0.671 A. is slightly shorter than r(C) = 0.691 A. The bond distance C—O = 1.421 A., the angle ∠COC = 112°24′, and ∠OCO = 110°49′. All the internal rotation angles of the skeletal bonds are 78°13′. It is deduced from the experimental results that each crystallite of polyoxymethylene is composed of only one type of helix, right-handed or left-handed.
    Additional Material: 8 Ill.
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  • 112
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 179-193 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to explain the observed nonvanishing limiting value of dynamic intrinsic viscosity of polymer solutions at ω = ∞ one has considered the necklace model with finite resistance to the rate of coil deformation introduced long ago by Cerf for the study of gradient dependence of intrinsic viscosity and streaming birefringence. The calculation need not take into account change of hydrodynamic interaction as a consequence of coil deformation because the experimental data are always either obtained at very low gradient or extrapolated to zero gradient so that in the experiment the macromolecule has the same conformation as in the solution at rest. The model indeed yields a finite [η]′ω = ∞ in good agreement with experiments on polystyrene in Aroclor. According to the theory [η]′ω = ∞/[η]0 decreases with increasing molecular weight as M-1 and M-1/2 for the free-draining and impermeable coil, respectively. The absolute limiting value [η]∞′, therefore turns out to be nearly independent of M, at least for small values of internal viscosity. From the observed value [η]∞′/[η0] one can obtain the coefficient of internal viscosity of the macromolecule. The value for polystyrene in Aroclor calculated from dynamic experiments on rather concentrated solutions is close to that derived by Cerf from streaming birefringence observations of polystyrene in a series of solvents of widely differing viscosity.
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  • 113
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 225-229 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 5 Ill.
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  • 114
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 211-223 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of radiation polymerization on a solid catalyst is discussed, under the condition that only linear termination of the chain takes place. All the kinetic equations are balance equations of particles of each type adsorbed by unit mass of the catalyst, and this makes it possible to account for the effect on the kinetics of the time dependence of the magnitude of the part of its surface on which the reactions we are considering may take place. Integro-differential equations are used for calculating the molecular weight distribution of the resulting polymer; this ensures higher accuracy of the formulas obtained than when differential equations are used and makes it possible to eliminate a number of limitations generally involved in the transition to differential equations. An expression has been found for the molecular weight distribution of the polymer product which allows for the possibility of radiation-induced catalytic polymerization on the resulting adsorbed polymer. Expressions have been derived for the average molecular weight and yield (weight and molecular) of the polymer formed. Asymptotic formulas have been obtained (for large irradiation times) for all the above values. The conclusions that can be drawn concerning the mechanism of the process based on a comparison of the formulas obtained with kinetic curves plotted from experimental data are given. It is shown how such a comparison can be utilized for calculating the rate constants for polymerization and chain termination reactions.
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  • 115
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 195-210 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A phenomenological theory is presented to extend the method of reduced variables for the effects of both temperature and changing degree of crystallinity on the linear viscoelastic properties of solutions of crystalline polymers. The vertical and the horizontal shift factors, which are both obtainable in the course of analysis of the experimental data, are correlated with the concentration of the solution and the volume fraction of the crystalline phase, and the fractional free volume of the system, respectively. Dynamic mechanical properties of a gel of cellulose nitrate (nitrogen content, 12.6%) in diethyl phthalate with a nominal concentration of 18% by weight were obtained in the transition region from glasslike to rubberlike consistency and also in the rubbery plateau region by employing the Fitzgerald apparatus and a freely oscillating torsion pendulum over the temperature range from -49 to 65°C. Application of the new reduction method to the experimental data was found to be quite successful, and it was shown that in general the degree of crystallinity in the system (and hence also the concentration of polymer in the amorphous phase) can depend on both temperature and thermal history. The dynamic mechanical data of a gel of different nominal concentration (23% by weight) previously obtained by Plazek were reanalyzed in terms of the method herein given.
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  • 116
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 230-234 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 117
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 235-236 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 118
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 391-393 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 119
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 361-375 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polysaccharide of salep orchid tuber was shown to be a glucomannan with a glucose/mannose ratio of 2.6 and an acetyl content of 2.1%. After extraction from the powdered root with water, the triacetate derivative was prepared and its configurational and hydrodynamic properties examined. The polymer yielded a series of fractions from 615 to 4170 in weight-average degree of polymerization. Light-scattering, viscosity, and osmometry experiments were conducted. Intrinsic viscosity results were interpreted according to the hydrodynamic theory of Eizner and Ptitsyn resulting in a value of ζ/η0 = 20 ± 6 A. for the ratio of monomeric friction coefficient to solvent viscosity and a corresponding value of a = 55 ± 4 A. for the persistence length, closely similar to those reported for other β-1,4-linked polysaccharides. The theoretical Flory coefficient increased with increasing molecular weight but was less than the limiting value of Φ0 = 2.86 × 1023 mole-1. The dependence of the light-scattering radius of gyration of the glucomannan polymer on the contour length showed that the configuration of the heteropolymer was similar to that of other β-1,4-linked polysaccharides which have only glucose or mannose in the main chain. Calculated radii of gyration based on the Porod-Kratky persistence length were found to be smaller than radii found by light scattering on the fractions.
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  • 120
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 583-596 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The optical and mechanical properties of poly(vinyl chloride) film were examined by observing both the stress and birefringence during stretching at constant rate, during relaxation at constant length and during a dynamic birefringence experiment. Experiments were also done by varying the temperature at constant length. The changes in birefringence are interpreted in terms of changes in negative distortional birefringence, changes in positive orientation birefringence, and possible reversible changes in birefringence with temperature arising from conformational changes in the polymer chain and changes in the contribution of birefringent crystals.
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  • 121
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 597-613 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependence of crystalline morphology of isotactic polypropylene crystallized from dilute solutions on its molecular weight and growing conditions and the mechanism of crystal growth were studied by electron microscopy and electron diffraction. Lathshaped lamellar crystals 150-300 A. in thickness are obtained from fractionated polypropylene powders of Mw (average molecular weight) = 600,000 and 240,000, but not from the samples of Mw = 82,000 and 44,000, by means of isothermal crystallization at 130°C. for 20 hr. in dilute α-chloronaphthalene solution (0.005 wt.-%). Precipitation of the fractionated polypropylene sample of Mw = 82,000 from a dilute solution of carbitol gives typical dendritic crystals under the same isothermal crystallizing conditions as mentioned above. The mode of chain folding in these crystals based on the orientation and the crystal structure of the lamellar crystals agrees with that proposed by Sauer, Morrow, and Richardson. From the morphological observations, the mechanism of growth pertinent to polypropylene lamellar crystals is presumed to be as follows: fibrils at first aggregate, then the molecular chains are folded to form small lamellae, and then these small lamellae accumulate compactly to grow to large, lath-shaped, lamellar crystals.
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  • 122
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 697-704 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the spin-lattice relaxation times (T1) of solvent protons have been performed on systems containing mixed solvents with and without polymer. It has been found that the motion of solvent is selectively affected by polymers present in the system. Polyisobutylene (10%) in mixed solvents of carbon tetrachloride (or cyclohexane) and dichloromethane at various proportions produces little effect on T1 values of dichloromethane, but it affects significantly the T1 values of cyclohexane; whereas poly(methyl methacrylate) (10%) in carbon tetrachloride and dichloromethane (or acetone) selectively associates with dichloromethane (or acetone), resulting in an approximate 50% reduction of the T1 values for dichloromethane (or acetone). In systems of poly(methyl methacrylate) and three mixed solvents of carbon tetrachloride, dichloromethane, and cyclohexane, the polymer (10%) has a negligible effect on the T1 values of cyclohexane, but brings about a 50% reduction of the T1 values of dichloromethane. These phenomena are discussed in terms of local selective interactions between the solvent molecules and the polymeric chain segments.
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  • 123
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 705-710 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recent precision measurements of the heats of combustion of atactic and isotactic polystyrene permit an unequivocal calculation of the enthalpy difference in the bulk amorphous forms of the two isomers of this polymer. Contributions to this quantity arise mainly from the differences in nonbonded interactions in the two configurations but may also contain terms relating to higher energy conformations and to intermolecular interactions. The thermochemical and NMR data of specific polymers and of simple molecules are discussed in a comparison with model compound calculations. The thermochemical method has potentially important applications in studying molecular interactions in stereoregular polymers.
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  • 124
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Tian-Calvet microcalorimeter has been used to measure the heat of solution of atactic polystyrene in toluene at 30°C. By using a special technique for polymer sample preparation, it has been possible to measure directly the difference in conformational energy of the polystyrene chain at different temperatures, from 30 to 100°C. and to calculate its contribution to the specific heat.
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  • 125
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 711-742 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A general method is presented for taking into account changes in volume in several types of calculations concerned with spherulite deformation in semicrystalline polymers. The method is applicable at large strains for which the low-strain limiting form of the equation defining Poisson's ratio is no longer valid. Applications are made to calculations of the three crystal orientation functions for models of spherulite deformation based on those proposed by Wilchinsky, Stein et al., and Oda et al. The effects of changes in volume are considered in detail and are compared with previous results in which the volume change was neglected. Calculations of spherulite birefringence are considered in a similar manner, as are the equations for determining spherulite deformation by means of low-angle light-scattering measurements. Results indicate that in several cases details of deformation mechanisms previously proposed should be revised in light of the effect of the change in volume on the calculated orientation functions. The equations in each case are presented in terms of a parameter β, the square root of the third strain invariant of the deformation tensor. Results are presented in numerical form for many of the basic parameters. Equations for all such results are expressed in explicit form and, in most cases, are displayed graphically together with available experimental data.
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  • 126
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 761-769 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The α, β, and γ transitions at temperatures between -200 and +100°C. of crosslinked aromatic and aliphatic epoxy polymers were determined from damping and shear modulus data, and compared with their fluorine containing analogs. Loci of segmental relaxation are suggested at various temperatures, and similarities between aliphatic and fluorocarbon segments, and polyethylene and polytetrafluoroethylene are discussed. Two systems of structurally similar monomers 2,2,3,3,4,4-hexafluoropentane diglycidyl ether-1,5 and 1,4-butane diglycidyl ether, and 2,2-bis(4-glycidyl phenyl ether)hexafluoropropane and 2,2-bis(4-glycidyl phenyl ether) propane were polymerized with the aid of two diamine curing agents, namely, ethylenediamine and m-xylylenediamine. Polymers of the aromatic diepoxides showed transitions with peaks at -56°C. and above +70°C. Three main peaks were registered for the aliphatic and fluorocarbon diepoxides: at -125 and at -100°C., at -56°C., and at 0°C. It is suggested that the Tg is affected by an interdependence of relaxation of all components of the polymer main chain.
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  • 127
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 781-790 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A description is given of a modified cone-and-plate apparatus suitable for the measurement of the streaming birefringence of molten polymers. Some results are given of measurements on a polystyrene and a poly(dimethyl siloxane). Those on polystyrene are compared with solution measurements of the same material by use of the well-known Bueche-Harding parameter. Measurements on the silicone oil have been compared with measurements of the dynamic moduli on the same material, after ascertaining the validity of the stress-optical law for this system as well.
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  • 128
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 791-794 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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  • 129
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 795-798 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 130
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 799-816 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The concentration of solvent in the gel phase of a swelling polystyrene-divinylbenzene copolymer bead has been measured as a function of the radius by optical interference techniques. It is found that an appreciable gradient exists even shortly after the core disappears. Results are presented for two cases: a very lightly crosslinked bead that exhibits negligible birefringence while swelling, and a more tightly crosslinked network in which the birefringence must be considered. It is also found that the refractive index of the unswollen bead is considerably less than that found by extrapolation from the swollen state; this effect is reasonable when the “free volume” in the bulk polymer is considered.
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  • 131
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 817-828 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dispersion of birefringence in oriented amorphous polymers is discussed. It is shown that for polystyrene, the birefringence can be considered as the product of an orientation function and a function of the wavelength of the light. This leads to a method for expressing the birefringence dispersion as a function that is characteristic of the polymer. This function is determined for polystyrene, and from it the birefringence at infinite wavelength is found to be 11% lower than that measured with the mercury green line (5461 A.).
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  • 132
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 829-838 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The molecular dimensions of polydipropylsiloxamer were studied by intrinsic viscosity measurements in toluene and in 2-pentanone. The relationships between the molecualr weight and the intrinsic viscosity were found to be: [η]25°C., toluene = 4.35 × 10-4 M0.58; [η]θ(10°C.), toluene = 1.09 × 10-3 M0.5; [η]θ(76°C.), 2-pentanone = 8.71 × 10-4 M0.5. This held reasonably well for molecular weights from 25,000 to 3000,000. The root-mean-square end-to-end length ratio, (r02/M)1/2 as calculated from the constant K, exceeds the free rotation value by approximately 100%. The disparity is greater than that found with polydimethylsiloxamer, indicating a lower degree of flexibility for the polydipropylsiloxamer. This is largely due to the short range steric interaction between near neighboring units of the chain. Gel permeation chromatography was also employed to demonstrate the lower degree of flexibility for polydipropylsiloxamer as compared with polydimethylsiloxamer.
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  • 133
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 853-874 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In earlier work we have indicated a superposition principle for moderately concentrated mixtures (c ≲ 2/[η]) in good and poor solvents. By an examination of data on a number of vinyl polymers and cellulose derivatives in good as well as poor solvents, the validity of this principle is extended to concentrated solutions (c ≲ 50%). The characteristic concentration factor γ is proportional to M-a1 over the whole concentration range, with 0.47 ≤ a1 ≤ 1.10 being larger for good than for poor solvents, the result obtained earlier. Significant deviations from this relationship are noted in good solvents for those low molecular weights at which deviations from the usual intrinsic viscosity relationship occur. This may be related to the expansion factor of the polymer coil. On the basis of these results, the concentration and molecular weight dependence of the viscosity in the concentrated solution can be related to each other in terms of the parameter a1 and thus to thermodynamic characteristics. In this manner a bridge between the relatively dilute and concentrated regions is established. Currently used semiempirical expressions are analyzed in terms of these results. For the polystyrene-cyclohexane systems and θ - 9 ≦ T ≦ θ + 3, γ can be identified with the critical concentration for phase separation. Provided an “entanglement” concentration ce exists, in the neighbourhood of which the concentration dependence of the viscosity changes reapidly, γ can alternatively be shown to be proportional to ce, or ce ∝ M-a1. The temperature reduction scheme suggested earlier remains to be investigated.
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  • 134
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular weight M and concentration c dependencies of the zero-shear viscosity (η) were measured over wide ranges of M and c for concentrated solutions of linear and branched poly(vinyl acetate) as well as of polystyrene under θ conditions. The log η versus log M and log η versus log c curves for a given system can be superposed by the horizontal shift along the abscissa, giving smooth master curves. From the shift factors the ratio of two exponents β and α, which appear in the following equation, can be evaluated: η = K′(cρ)αMβ, where ρ is the density of the solution and K′ is a constant at constant temperature. The evaluated values of β/α for the systems under θ conditions are equal to or very close to 0.50 as was anticipated from the previous work. The above superposition method was also applied to available viscosity data, and it was found that β/α had a good correlation with a in [η] = KMa. This indicates that the individual molecules in concentrated solutions maintain the same individuality as in dilute solutions, and might be a positive support to the packed sphere model proposed previously by the authors. The effect of solvent on the molecular weight and the concentration dependencies of viscosity was also discussed.
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  • 135
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 915-927 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The homopolymer and many of the copolymers of N-acrylylglycinamide yield thermally reversible gels in water. These systems are uniquely suitable for studying synthetic photographic gelatin substitutes and for understanding the mechanism of the gelation process. Polymerization of N-acrylylglycinamide has been studied under a variety of conditions. The homopolymer is aggregated in dilute aqueous solution and probably molecularly dispersed in 2M thiocyanate solution. At concentrations of several per cent, in water, thermally reversible gels are formed whose melting points rise with increasing concentration and increasing molecular weight. The heat of gelation crosslinking has been calculated to be -8.8 kcal./mole of crosslinks. Introduction of small amounts of carboxyl groups into the polymer raises the melting points of the aqueous gels. The effect of various organic and inorganic reagents on gelation is presented. The ability to prepare copolymers which can be flocculated has been demonstrated as well as the usefulness of the monomer in certain types of photoresist systems. Copolymerization with acrylic acid and β-aminoethyl vinyl ether has been studied, and the r1 and r2 values for these systems have been calculated as well as Q and e values for N-acrylylglycinamide.
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  • 136
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 929-938 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Free radicals produced in irradiated polypropylene were studied by the electron spin resonance method. Two temperature regions in which the free radicals decay rapidly were found at around 170°K. and 260°K. The first temperature region corresponds to the γ-dispersion of polypropylene and the second to the β-dispersion. Steric configurations of the free radicals were investigated, and it was concluded that the free radicals trapped in polymer, conformation of which is appreciably twisted from the stable 31-helical structure, decay with small-scale motion of the matrix polymer. The decay of free radicals trapped in polymer of less twisted conformation is associated with the large-scale motion of the matrix polymer. Activation energies of decay were found to be 11 kcal./mole at the lower temperature and 48 kcal./mole at the higher temperature. Time constants of the decay reactions were compared with those for molecular motion of the matrix, with results reflecting the relations of the decay of the polymer radicals to molecular motion in the matrix.
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  • 137
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 939-955 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The deformation of fresh and aged polybutene-1 spherulitic samples has been investigated by microscopic observation, interferometry, studying macroscopic and spherulitic birefringence changes, and study of light-scattering patterns. The spherulite deformation is not affine, the microscopic deformation ratio being less than the macroscopic deformation ratio of the sample and greater in the equatorial regions of the spherulite than in the polar regions. The deviation from affine deformation is less for fresh spherulites than for the aged, where void formation occurs in the equatorial part of the spherulite. This gives rise to large scattering by this part of the spherulite and to form birefringence. The spherulite birefringence and its change with elongation is dependent upon the degree of aging of the sample. The spherulite birefringence is more negative for the aged sample. In the polar regions of the spherulite, this negative birefringence decreases and turns positive at higher elongations, characteristic of a reorientation of the crystals with their optic axes turning from being perpendicular to parallel to the spherulite radius. The spherulite birefringence in the equatorial direction becomes somewhat more negative on stretching a fresh sample but less negative on stretching an aged one. Spherulite distortion and orientation changes are apparent from the light-scattering patterns of films possessing small spherulites. The changes in Vv and Hv scattering patterns upon stretch are different for the fresh and aged samples. The Vv patterns of the fresh samples decrease in intensity with time after stretching a fresh sample with the Hv patterns do not.
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  • 138
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 987-988 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 139
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 989-989 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 140
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1013-1028 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The influence of the species of counterion on the polyelectrolyte behavior and the conformation of poly-L-methionine S-methylsulfonium salts in aqueous solution was studied by viscometric, electrochemical, and optical measurements. The degree of binding of small counterions to charged polyions increases in the sequence: chloride ≲ bromide 〈 iodide 〈 thiocyanate. The conformations of chloride and bromide salts are independent of polymer concentration. On the contrary, iodide and thiocyanate salts indicate a conformational transition, probably from a random-coil conformation to an intermolecularly stabilized β-form, with the increase of polymer concentration. The results suggest the existence of a strong specific interaction between counterion and macroion in iodide and thiocyanate salt solutions at high polymer concentration.
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  • 141
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 991-1012 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Single-crystal preparations of polyethylene were treated with the selective oxidizing agent, fuming nitric acid. The degraded products were examined as regards layer thickness (by low-angle x-ray studies), chemical and weight changes, recrystallization and annealing treatments, and by broadline NMR, as part of a systematic investigation aimed at clarifying the nature of disordered material in single crystals. It emerges that there is a disordered-mobile region along the fold surface of the crystals in agreement with other parallel works along similar lines. In a more detailed analysis we can now decompose the nitric acid attack into components affecting the basal and side surfaces, respectively. Taking into account the recrystallization-annealing observations, we infer that the fold surface is heterogeneous with folds of more than one kind. These results were combined with a preliminary molecular weight distribution study by gel permeation chromatography. Taking into account all the available evidence, we are led to suggest a composite structure where surface looseness, coresponding to long loops and hairs, is superimposed on the more regular folded surface. This model is in the process of being tested. The problems concerning the assignment of a value to the amount of surface looseness are being discussed. In addition, a discontinuity in the thermal behavior of the crystals between 75 and 80°C. has been detected.
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  • 142
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1029-1042 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper is devoted to the determination of the number of intermolecular bonds in a polymer crosslinked according to the following process: (1) crosslinking in the usual isotropic state, (2) additional crosslinking of the strained primary network. The Flory equation for swelling in solvents has been modified in order to take into account the oriented state of the initial network at the time of secondary crosslinking. The combination of this equation with those relating the modulus of elasticity and the dimensions of the relaxed sample to the deformation of the primary network at the time of secondary crosslinking leads to different possible evaluations of the number of intermolecular bonds. Their significance is discussed. The equations thus established are tested with natural rubber samples vulcanized according to the above-mentioned process. The validity of the number of crosslinks thus calculated is discussed; a partial degradation of the primary network occurs during the second crosslinking. Its influence is taken into account by using the approximated equations proposed by Flory. The efficiency of the vulcanizing agent (TMTD) is consequently shown to be practically independent of the deformation of the primary network at the time of secondary crosslinking.
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  • 143
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    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1087-1101 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of long-chain branching on the size of low-density polyethylene molecules in solution is demonstrated through solution viscosity and molecular weight measurements on fractionated samples. These well-characterized fractions are analyzed by gel permeation chromatography (GPC), and it is shown that the separation of the polymer molecules by this technique is sensitive to the presence of long-chain branching. By using fractions of branched polyethylene possessing differing degrees of branching, one observes that a single curve is adequate in relating elution volume to molecular weight. This calibration curve is applied in the GPC analysis of a variety of commercial low-density polyethylene resins and it is shown, by comparison with independent osmometric and gradient elution chromatographic data, that realistic values for molecular weight and molecular weight distribution are obtained. The replacement of molecular weight M by the parameter [η]M as a function of elution volume, leads to a single relationship for both linear and branched polyethylenes. This indicates that GPC separation takes place according to the hydrodynamic volumes of the polymer molecules. The comparison of data for polyethylene and polystyrene fractions suggests that this volume dependence of the separation will be observed for other polymer-solvent systems.
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  • 144
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    AIChE Journal 13 (1967), S. 1196-1202 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two-phase, gas-liquid concurrent flow in packed beds was investigated with the use of an air-water system and 2-, 4-, and 6-in. diameter columns packed with tabular alumina particles of 0.025 and 0.027 ft. diameters. Total pressure drop, column operating pressure, and liquid saturation were measured as functions of gas flow rate, fluid temperatures, and flow direction at several constant liquid flow rates for each column.Correlation of the frictional pressure loss was achieved in terms of a defined two-phase friction factor and a second correlating parameter which is a function of the liquid and gas Reynolds numbers. A viscosity correction factor was required to extend the friction factor correlation to include liquid viscosities widely divergent from that of water.The liquid saturation data for both upward and downward flow were correlated in terms of the ratio of mass flow rates of the respective phases.
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  • 145
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    AIChE Journal 13 (1967), S. 311-315 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A previous paper introduced the pair-type-probability (PTP) function for use in molecular corresponding states theory. The present paper develops the predictive equations of Scatchard and Hildebrand and the correlation equations of Wohl from particular pair and triplet weighting functions for clusters of two and three molecules in a liquid mixture. The cluster-weighting idea therefore unifies the major prediction and correlation schemes now in engineering use.
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  • 146
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    AIChE Journal 13 (1967), S. 303-311 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: There are four points of flexibility in present molecular formulations of the corresponding states idea. At these points the procedure followed or the numerical values can be tailored to achieve better agreement between predicted and experimental properties without violation of physical principles. These flexibilities are the exponent values used in the pair-potential function, the averaging procedure used to obtain an effective mixture pair-potential function, the combination rule for unlike-pair parameters, and the selection of a reference substance. The first two flexibilities are used in this paper to show that the conformal-parameter equations can correlate excess free energy and activity coefficient data of highly nonideal liquid mixtures. A pair-type-probability function is introduced in the averaging procedure used to obtain a mixture pair-potential function. Any macroscopic or molecular property may be used in this weighting function to improve mixture-property prediction.
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  • 147
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    AIChE Journal 13 (1967), S. 316-318 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The observation that large bubbles entrained in accelerating viscoelastic fluids may suddenly stop and remain stationary for long periods of time, although imbedded in a region of high fluid velocities, is noted and described. An analysis of this phenomenon, termed the Uebler effect, shows that it may be expected to occur with all particulate matter provided that the continuum field fluid is accelerating sufficiently rapidly to generate high stresses as a result of fluid stretching, and provided these stresses change sufficiently rapidly in the direction of the velocity vector in the flow field.
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  • 148
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    AIChE Journal 13 (1967), S. 319-326 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For a number of polymerization models, we have developed equations that enable one to follow in time the moments of the polymer size distribution and the conversion. The exact and approximate solutions for the leading moments of the size distribution are presented for polymerization with initiation, propagation, and termination by combination. Approximate solutions for polymerizations with the additions of termination by disproportionation, chain transfer to monomer, and chain transfer to solvent show how these reactions decrease the average polymer size. From a simple model that exhibits autoacceleration a concomitant increase in the average polymer size also occurs.
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  • 149
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    AIChE Journal 13 (1967), S. 395-396 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 150
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    AIChE Journal 13 (1967), S. 438-442 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In a high-pressure process, feed streams are continually pressurized and product streams are continually depressurized. A flow work exchanger offers an efficient and economical scheme for simultaneously pressurizing a fluid stream and depressurizing a substantially equivalent volume of another fluid stream. Its applicability is however limited to fluids under condensed state. A flow work exchanger uses a displacement vessel to form a closed loop with a processing system. The displacement vessel is alternately filled by a low-pressure feed and a high-pressure product, both pressurized and depressurized, respectively, by substantially nonflow processes. The pressurized feed is pushed into the processing system by the high-pressure product stream and the depressurized product stream is pushed out of the displacement vessel by the low-pressure feed stream. The application of a flow work exchanger is illustrated by means of several high-pressure processes and the direct and indirect advantages obtainable are described.
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  • 151
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    AIChE Journal 13 (1967), S. 443-449 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Local and average holdup and drop size distribution as function of flow rates were measured for kerosene drops and water in a countercurrent, 15-cm. I.D., 160-cm. long, spray column. The range of flow rates was 5 to 40 liters/min. of kerosene and 0 to 50 liters/min. of water. At the same pairs of flow rates of the dispersed and the continuous phases in spray columns, three modes of drop packings can be obtained. These are termed, in order of increasing average holdup and increasing regularity of flow patterns, dispersed, restrained, and dense packings. For dispersed packing, at low flow rates of the two phases, the holdup and the drop size are constant along the column. At high flow rates the drop size increases from bottom to top of the column and the holdup increases from top to bottom of the column. The range of flow rates for the operation of a spray column is extended by the use of a conical entry section (Elgin design) at the bottom of the column, by the formation of an equilibrium region in the conical section.The average holdup increases with increased flow rates of both phases for dispersed and restrained packings, and with decreased flow rates of both phases for dense packing.The best definitions of flooding in a spray column are either the point of maximum average specific area of the drops, which corresponds to the onset of coalescence in the column, or the start of rejection of drops from the column proper.
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  • 152
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    AIChE Journal 13 (1967), S. 449-452 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An analytic solution of the Nernst-Planck equations is derived which applies to a selective resin when film diffusion controls. The selectivity has a marked effect on the rate of exchange for a wide range of diffusivities. The unit-selectivity solution of Schlögl and Helfferich is included as a special case of the more general solution.
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  • 153
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    AIChE Journal 13 (1967), S. 453-456 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental results are presented which indicate that the application of a fixed intensity of ultrasonic waves to a water-tetrachloride solution containing dissolved air provides yields of chlorine varying from zero to maximum simply as a function of the liquid height in the capillary above the transducer. The difference in heights of the liquid between zero and maximum yields is found to be equal to one-quarter the wavelength of the ultrasonic wave in the liquid. A mathematical model to explain this phenomenon is presented.
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  • 154
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    AIChE Journal 13 (1967), S. 457-465 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Removal of methane from a helium stream by adsorption on Columbia SXC activated carbon was studied experimentally and theoretically. A mathematical model for the process was developed and the governing differential equations were solved numerically. The model incorporates heat and mass transfer resistances within and around the adsorption particle. Wall effects and moderate heat loss to the surroundings are also included. The required heat and mass transfer correlations were obtained from the literature. Simple expressions were developed to determine the relative resistances for heat and mass transfer within and around the adsorption particles.
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  • 155
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    AIChE Journal 13 (1967), S. 465-475 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Frequency response methods were used to compare dynamic models for gas mixing and first-order reaction in a fluidized-bed reactor and for the experimental determination of interphase transfer characteristics. Theoretical predictions of frequency response characteristics were derived for two models based on the two-phase theory of fluidization. Experimental frequency response for a 1-ft. high bed were correlated better by a model based on perfect mixing in the dense phase than by a model based on plug flow in the dense phase. Excellent correlation was also obtained by a simple empirical model.
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  • 156
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    AIChE Journal 13 (1967), S. 540-545 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Methods are presented for the determination of the transient values of the vaporization efficiencies from the knowledge of various combinations of the transient values of operating variables. For the case where the temperature and the composition of the liquid phase for each plate are known, a direct solution for the vaporization efficiencies is presented. Also, a method is presented for the determination of the mixing parameters of a generalized plate model on the basis of known transient values of certain operating variables.
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  • 157
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    AIChE Journal 13 (1967), S. 545-550 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Irreversible, first-order, simultaneous heterogeneous and homogeneous reactions in an isothermal tubular reactor under laminar flow conditions are studied. Accurate values of the eigenvalues, eigenfunctions, and radial concentration profiles are found for the dilute system. Criteria are given as to when the homogeneous reaction may be neglected with respect to the heterogeneous reaction and vice versa. It is found that for a certain range of the rate parameters well-known limiting solutions apply. Outside this range, the new solutions must be used.
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  • 158
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    AIChE Journal 13 (1967), S. 593-599 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Liquid and gas phase compositions for the system helium-methane have been measured at 15° intervals from 95° to 185°K. up to 200 atm. pressure. Data for these seven isotherms were taken in a gas phase recirculation apparatus with chromatographic analysis. In most regions the phase compositions obtained are thought to be within ± 3% of the mole fraction of the minor component. The maximum deviation from the enhancement factor curve at the lowest concentration levels was 16%. These data are in excellent agreement with most of the very recent data but are in poor agreement with the older data for this system.
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  • 159
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    AIChE Journal 13 (1967), S. 607-607 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 160
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    AIChE Journal 13 (1967), S. 614-615 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 161
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    AIChE Journal 13 (1967), S. 626-626 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 162
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    AIChE Journal 13 (1967), S. 626-831 
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    Keywords: Chemistry ; Chemical Engineering
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  • 163
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    AIChE Journal 13 (1967), S. 627-627 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 164
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    AIChE Journal 13 (1967), S. 826-827 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 165
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    AIChE Journal 13 (1967), S. 828-829 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 166
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  • 167
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    AIChE Journal 13 (1967), S. 829-830 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 168
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    AIChE Journal 13 (1967), S. 628-636 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical investigation has been made of the effect of a moving interface upon gas-liquid mass transfer, where the control of the mass transfer is entirely within the gas phase and where the control is distributed between the two phases. An analytical model is proposed for laminar interphase mass transfer in infinite media. Computer solutions have been obtained for gas-liquid mass transfer in confined phases. A cocurrent moving interface increases mass transfer confficients over what they would be for the same flow rate without interfacial motion.
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  • 169
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    AIChE Journal 13 (1967), S. 644-649 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Accompanied by a bried theoretical consideration, the results of an experimental study of the streaming potential fluctuations in turbulent pipe flows of distilled water are presented. The dependence of the streaming potential fluctuations on turbulent velocity fluctuations and other parameters as indicated by the theory is determined from the experimental data. Information on the characteristics of turbulent velocity fluctuations in the viscous sublayer near a pipe wall have been inferred from the data.
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  • 170
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    AIChE Journal 13 (1967), S. 637-644 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A horizontal, rectangular channel of high aspect ratio has been built for the study of interphase mass transfer in stratified, laminar gas-liquid flow. Cases were examined where the resistance to mass transfer is confined to the gas phase and where the control is distributed between phases. Measurements of the rate of evaporation of ethanol into oxygen and carbon dioxide confirmed that cocurrent interface motion enhances gas phase-controlled mass transfer coefficients substantially. On the other hand countercurrent motion of the interface decreases the coefficient. Agreement with basic convective diffusion theory was found for the evaporation of ethyl ether into helium and carbon dioxide from dilute solutions in ethanol, cases where the mass transfer control is distributed between the phases. Experiments with aqueous solutions were hampered by the accumulation of surfactants at the interface. A diaphragm cell technique was used to measure diffusivities of 0.87 × 10-5 sq.cm./sec. for ethyl ether at high dilution in ethanol and 0.96 × 10-5 sq.cm./sec. for ethyl ether at high dilution in water at 25°C.
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  • 171
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    AIChE Journal 13 (1967), S. 689-696 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments on mass transfer for fully developed flow in a pipe show that the eddy diffusivity for mass close to the wall is described by the functionality \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{\varepsilon} {\nu} = g({y^+}) $$\end{document}The best interpretation of presently available data in a pipe and in an annulus is given by the following, more explicit relation \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{\varepsilon} {\nu} = 0.00032y^{+ 4} $$\end{document}The evidence for this latter relation is not as conclusive as one would like. Accurate measurements of concentration profiles close to a wall are needed.
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  • 172
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    AIChE Journal 13 (1967), S. 697-702 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Single bubbles of carbon dioxide were formed in a fixed position surrounded by a thin conical film of water flowing at average film Reynolds numbers in the range of 40 to 300. Measurements of interphase mass transfer at 32°C. and various bubble pressures agreed with predicted values only for the smallest bubbles. For larger bubbles, mixing perpendicular to the bubble interface was enhanced by waves, believed to be generated by the unstable interface. A comparison of interphase transfer coefficients between this investigation and previous work indicated that the bubbles at the lowest flow rates qualitatively fell in line with other measurements, but that the highest water flow rates gave distinctly higher coefficients.
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  • 173
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    AIChE Journal 13 (1967), S. 709-717 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A horizontal thermal diffusion column is described in which the inefficiencies caused by the forgotten effect and parasitic remixing are avoided. Experimental results obtained on the separation of water-ethyl alcohol mixtures are presented along with a phenomenological theory for the performance of the column.
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  • 174
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    AIChE Journal 13 (1967), S. 702-708 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Measurements of laminar dispersion in a capillary have been used to determine the molecular diffusion coefficients of hydrogen and helium dissolved in water over the temperature range of 10° to 55°C. Literature correlations did not predict realistic values of the diffusivities for the hydrogen - water and helium - water binaries. A statistical analysis of the experimental diffusion coefficients indicated that they could be related to the absolute temperature by a semiempirical correlation, which may be considered an extension of the well-known Wilke-Chang correlation. This relation was based on the absolute reaction rate model of liquids.
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  • 175
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    Notes: The P-V-T-x phase relations of helium - n-butane system were measured in the region of low helium content (up to 10.4 mole % helium). The system exhibits the gas-gas equilibrium originally predicted by Kamerlingh-Onnes and Keesom. The term gas-gas equilibrium is applied because the critical temperatures of the mixtures are higher than the critical temperature of either component. This behavior is quite unlike that observed in most binary systems, in which the critical temperature of the mixtures lie between those of the pure compounds. As a consequence of the shape of the critical locus curve, the system exhibits isothermal retrograde condensation of the second kind.
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  • 176
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    AIChE Journal 13 (1967), S. 745-750 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The speed range of the low-speed theory for cylinder withdrawal is extended by a correction for gravity and a modified use of the thin meniscus assumption. Experimental evidence indicates that this gravity corrected theory holds over a 3,000-fold range of speed, in terms of capillary number. This gravity corrected theory reduces, as special cases, to several other previously published theories as well as to the low-speed theory.
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  • 177
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    AIChE Journal 13 (1967), S. 759-763 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this paper a conjecture of Aris is proved to be correct, that of all catalyst particles of fixed volume for isothermal first-order chemical reactions the spherical particle has the lowest effectiveness factor. The method of proof uses a process of symmetrization. Some conjectures are also made about other chemical reactions. The method of proof is also valid for two-dimensional domain (infinite cylinder).
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  • 178
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    AIChE Journal 13 (1967), S. 764-768 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Single seed crystals of potassium chloride were grown from aqueous solutions under conditions of constant temperature, supersturation, and impurity concentration. With emission spectrography as the method of analysis, the distribution of various metal ion impurities between the grown potassium chloride crystal and the solution was studied. The distribution coefficients of Pb++, defined as the ratio of the impurity concentration in the crystal to the concentration in solution, were found to be greater than unity at very low concentrations. The lead distribution coefficients varied between 2,700 for solutions containing 10-8 moles of lead/mole of potassium chloride to 28 (for solutions of 10-5 moles of lead/mole of potassium chloride).The results suggest a mechanism of nonequilibrium capture of the impurity. The magnitude of the distribution coefficient is shown to depend on the equilibrium distribution coefficient between the solution and surface of the crystal, the rate of growth of the crystal, and the rate of diffusion of the impurity through the crystal lattice. These results are believed to be of significance in the purification of materials by fractional crystallization. For instance, they indicate that in order to produce crystals of lead-free potassium chloride, the conventional techniques or recrystallization should be modified to include rejection of the first crystals grown.
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  • 179
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    AIChE Journal 13 (1967), S. 779-783 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bubble frequencies and departure volumes in nucleate pool boiling have been obtained for a variety of liquids at pressures ranging from 50 to 760 mm. Hg. The bubble dynamic data conclusively show the volumetric vapor flow rate to be a strong function of the Jakob number in qualitative agreement with the heat transfer measurements of Nickelson and Preckshot. The data also indicate the volumetric vapor flow rate per cross section to be independent of the Jakob number, in agreement with existing equations.
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  • 180
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    AIChE Journal 13 (1967), S. 768-778 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Discrete control algorithms, suitable for programming in a direct digital control computer, are presented. For processes whose dynamics can be adequately modeled as first order with delay, digital compensation algorithms are derived to yield theoretically a response with finite settling time, when the system is step forced in either set point or load. The utility of the proposed designs is experimentally verified by application to a higher order physical process whose dynamics are not fully described by the model. The results demonstrate that sampling frequencies may be reduced considerably below presently accepted values while still maintaining transient response characteristics of the system comparable with those obtainable from conventional continuous control.
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  • 181
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    AIChE Journal 13 (1967), S. 915-925 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The chlorination of propane was studied in a tubular flow reactor, with outside illumination, at atmospheric pressure. At chlorine concentrations of less than 1.5 mole % (and inert nitrogen above 94%) a second-order (in chlorine) rate expression was indicated. At higher chlorine or propane concentrations propane affects the rate. Two rate equations, based upon different termination steps for the chain carriers, were found to fit the data. For the low concentration region the apparent activation energy for the overall reaction was 3.4 kcal./g.-mole. Most of the measurements were carried out with polychromatic light, but data taken with a narrow band of radiation, over the range 2,200 to 5,400Ā, showed an increase in rate with decreasing wave length. As a first step toward reactor design, differential reactor data were used to predict the conversion for laminar flow, integral reactor conditions. A reactor model which included the effects of residence time distribution and radial variation in light intensity gave good agreement with experimental data. A plug-flow model was less satisfactory.
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  • 182
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    AIChE Journal 13 (1967), S. 931-935 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The general form of the equations describing a steady, two-dimensional flow of an incompressible liquid is reduced to a form containing only two parameters. The histories of stress and of deformation of a material element are written explicitly. A second-order, slow-flow approximation and a Maxwell type of constitutive equation are used to infer properties of the rheological behavior of viscoelastic liquids in such flows.
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  • 183
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    AIChE Journal 13 (1967), S. 936-947 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new calculation method presented here for interpreting batch or tubular-flow reactor data (and also CSTR data) on three-component, three-reaction reversible systems is based upon the general analyses of Jost and of Wei and Prater. With advance knowledge of the pertinent equilibria, even a very few experimental points can be matched easily and rapidly to the given figures and equations. The simplification involved when one reaction disappears, with the divariant system thus becoming monovariant, is also described. Representative concentration-time curves are given for design purposes.
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  • 184
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    AIChE Journal 13 (1967), S. 926-931 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In most control applications in the chemical process industries it is not realistic to attempt to define a unique mathematical statement of the control objective, for many criteria will satisfy the physical requirement of the rapid elimination of errors in the product stream as the result of an upset. The strong dependence of the structure of an optimal control system on the choice of objective then makes optimal control theory irrelevant in such situations, since the control engineer has no assurance that a complicated controller is a necessity of the process, rather than a consequence of an unfortunate choice of objective. In this paper an inverse problem is considered, in which an easily implementable feedback control system is first chosen and then is shown to be optimal for a physically meaningful objective in a large class of systems.
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  • 185
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    AIChE Journal 13 (1967), S. 948-954 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The results of an analytical and experimental study of compressible, axially symmetric, turbulent free jets exhausting into quiescent air are presented. A finite-difference technique was used to obtain a general solution which has eliminated the need for the simplifying assumptions required in previous investigations. The jet Mach number and jet temperature ratio have been found to be the only two initial jet properties which are necessary to characterize the dimensionless velocity and temperature variations in this type of jet. Modifications of dynamic eddy transfer coefficients given in the literature are used in the solution An experimental program was carried out to obtain data on free jet velocity and temperature variation at high initial jet temperatures and high subsonic Mach numbers where there has been a lack of experimental data. The numerical solutions of the time-averaged conservation equations have been shown to agree well with the experimental data of the present study and of previous investigations.
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  • 186
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    AIChE Journal 13 (1967), S. 1018-1019 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 187
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    AIChE Journal 13 (1967), S. 1020-1024 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 11 Ill.
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  • 188
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    AIChE Journal 13 (1967), S. 1025-1028 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 189
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    AIChE Journal 13 (1967), S. 1030-1031 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
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  • 190
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    AIChE Journal 13 (1967), S. 1072-1077 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Volumes translated in wakes of single drops of organic liquids rising through aqueous media have been measured. Organic drops studied comprised methyl isobutyl ketone, toluene, and toluene-carbon tetrachloride mixtures. Aqueous media comprised water and water-sugar solution. Distance of drop rise varied from 10 to 20 in. Drop size was varied such that Reynolds numbers of 40 to 800 were obtained. Volumes translated were nearly independent of distance for nonoscillating drops and decreased rapidly with distance for oscillating drops. Transition from nonoscillating to oscillating drops occurred at Reynolds number of 200. Measurements of drop velocities were also made.
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    AIChE Journal 13 (1967), S. 1141-1154 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Under some conditions, continuous crystallization exhibits cyclic changes of the particle size even with constant input conditions. A linearized stability analysis has been performed to determine under what conditions this behavior can be expected. Numerical solutions of the actual nonlinear system equations were carried out to follow the cyclic behavior and to compute the cycle time and the amplitude of the fluctuations. The effect of seeding on the stability limits and product distribution was also evaluated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 192
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 1160-1166 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental investigation of heat transfer rates in which were used three spray towers varying from 4 to 6 in. in diameter and 7 to 10 ft. in height, and distributor elements with hole sizes varying from 1/8 to 1/64 in. in diameter was carried out. The immiscible liquid system consisted of water and kerosene (normal boiling point range 395° to 490°F.). Volumetric heat transfer coefficients ranged from 100 to 3,600 B.t.u./(hr.)(cu. ft.)(°F.) and the overall film heat transfer coefficients ranged from 4 to 23 B.t.u./(hr.)(sq. ft.)(°F.). Height equivalent to a theoretical stage varied from 1 to 8 ft. Scale-up correlations relating these rate data to operating variables were developed.
    Additional Material: 9 Ill.
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  • 193
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 1155-1159 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The pressure drop of water was measured when water flowed through a bed of stainless steel ball bearings packed in an ordered rhombohedral geometry. Experiments were carried out with eleven different packed beds, encompassing the entire range of the square-base array, in the same 10.85 by 10.85 by 30-in. rectangular test column in a forced circulation loop at modified Reynolds numbers up to 17,000. The test variables included water velocity, bed voidage, spacing between adjacent balls, ball diameter, and bed height. Curves of friction factor vs. Reynolds number are presented. An increase in the relative horizontal spacing between balls was found to have a more important effect than an increase in voidage in decreasing the pressure drop. A general correlation relating the mutual effects of bed voidage and ball spacing on pressure drop that would bring all the data points together, especially in the transition flow region, could not be found. As a result, the system appears to consist of two distinct parts separated at the minimum packing density. A correlation was found only for the first, but from a practical point of view more important, region. Data may be corrected for bed voidage, but only for small variations in ball spacing, by the ratios of (1 - ε)/ε3 at the two voidages. No entrance and exit effects could be measured beyond the first seven ball layers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 194
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 1171-1174 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A relationship for the diffusion coefficient of a dilute species in a mixture of two solvents is developed. The result, based on the linear additivity of the frictional activation energy which is valid for completely miscible, nonassociated systems, predicts the diffusion coefficient of the solute in terms of the limiting values of the diffusion coefficient of the solute in each of the solvents, the limiting values of the solvent pair diffusion coefficient, and two thermodynamic factors. The equation is confirmed for some recent experimental data.
    Additional Material: 2 Ill.
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  • 195
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 1175-1180 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of viscous dissipation on fully developed laminar forced convection with heat sources in various regular polygonal ducts under the thermal boundary conditions of uniform wall heat transfer per unit duct length and circumferentially uniform wall temperature are approached by the method of point matching. The method uses the exact solutions to the governing partial differential equations and satisfies the boundary conditions exactly only at selected points. This method complements the method of complex variables for various noncircular geometrical configurations where the velocity and temperature fields are not deducible directly from the boundary equations. The relationship between the average velocity and the average of (grad u)2 over the cross section is pointed out. Other useful relationships between heat transfer quantities based on analogy or the observation of the results from literature and present investigation are also pointed out. The numerical results presented can be used to evaluate the effects of viscous dissipation on mean temperature, overall heat transfer rate at the boundary, heat transfer coefficient and Nusselt number. Graphical results for the representative cases are also presented for the heat transfer rate and the Nusselt number.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 196
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 3-3 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 197
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967) 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 198
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 2-2 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 199
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 10-16 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method of analysis is presented for determining closed-form solutions for two-component stratified laminar flow in horizontal ducts of arbitrary cross section. It is demonstrated that the method is remarkably easy to apply and produces results of high accuracy. As an application, solutions are obtained for stratified flow in a circular tube. The results are compared with various limiting cases and excellent agreement is found to exist. Among the limiting cases, an exact solution was derived by Green's functions for the problem in which the interface between the flow components is situated at the horizontal diametral plane.
    Additional Material: 4 Ill.
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  • 200
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 13 (1967), S. 17-20 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An optical technique for the quantitative determination of point velocities in rapidly developing laminar flows of transparent liquids is useful as an experimental tool in problems of complex geometries and fluids. The accuracy of the technique has been confirmed by comparison of experimental data with the numerical solution of the equation of motion for the entrance region problem. A distributor capable of generating a flat velocity profile has been developed for this purpose.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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