bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of nitrogen and neon pool boiling on a short vertical pipe
Authors: Lapin Abraham , Wenzel L. A. , Totten H. C. 
Published: June 2004

AbstractAn experimental study in the behavior of nitrogen and neon pool boiling was performed. The test section consisted of a vertical pipe 3 in. O.D. × 7½ in. long. The variables studied are: heat input, submergence, and surface finish. Several copper heaters were tested, in addition to nickel and cadmium plated heaters. The results were correlated for nitrogen by an equation which gave an average deviation of ± 16% for all the heaters except the cadmium plated heater. The paper describes the experimental equipment and technique, summarizes the data, and compares them to literature values and equations.
Generalized thermodynamic properties of real gases: Part I. Generalized PVT behavior of real gases
Authors: Viswanath D. S. , Su Gouq‐Jen 
Published: June 2004

AbstractThe object of this paper, first in the series dealing with the generalized thermodynamic properties of real gases, is to present generalized compressibility charts in the reduced temperature range of 1.0 to 15.0 and a reduced pressure range of 0 to 40.0. A detailed summary of deviations of the present charts with PVT values of different gases is presented. A summary of the comparison of the present charts with the existing charts is also given.
Analysis of phase‐boundary motion in diffusion‐controlled processes: Part III. Penetration of metal ions into cellulose xanthate fibers and growth of sulfuric acid droplets in humid air
Authors: Griffin J. R. , Coughanowr D. R. 
Published: June 2004

AbstractIn Part I (1) three general methods of solving moving‐boundary problems were developed, and in Part II (2) the three methods were applied to the problem of evaporation from a flat surface into a gas of infinite depth. In this final paper, more challenging problems in cylindrical and spherical coordiates are considered, and new solutions to these are presented.
Effect of the equilibrium relationship on the dynamic characteristics of distillation column sections
Authors: Mohr C. Michael 
Published: June 2004

AbstractThe dependence of the dynamic characteristics of distillation column sections on the shape of the equilibrium relationship and the number of plates comprising the section is discussed. Dynamic characteristics, valid near the steady state operating condition, were obtained for simple column sections separating binary mixtures by a straightforward calculation with a digital computer. Sections with concave downward equilibria respond significantly more slowly than comparable sections with linear equilibria. Sections with concave upward equilibria respond faster. This behavior is explained in terms of the internal recycle within the section. The rate of propagation of a disturbance from end to end in the section is only weakly influenced by the shape of the equilibrium relationship.
Foam fractionation of colloid‐surfactant systems
Authors: Grieves R. B. , Bhattacharyya Dibakar 
Published: June 2004

AbstractThe presence of colloidal particulates has a significant effect upon the foam fractionation of aqueous solutions of surface‐active agents. An experimental investigation is presented of the foam fractionation‐flotation of the stannic oxide‐cetyltrimethylammonium bromide (CTAB) and stannic oxide‐alkyl benzene sulfonate (ABS) systems. The average diameter of the stannic oxide particles was 180Å, and particle concentrations were determined by turbidmetry. For stannic oxide‐CTAB a froth flotation mechanism controls, and upon foaming feed sols of fixed concentration, fractional residuals of particulates and surfactant are approximately equal. Maximum enrichment ratios are obtained at maximum aeration time, minimum air rate, and maximum foam height. Increasing the feed concentration of particulates increases the collapsed foam volume, while the CTAB concentration in the residual sol first decreases and then becomes virtually constant. For stannic oxide‐ABS sols, no particulates are removed preferentially in the foam. A foam fractionation mechanism controls, and compared with ABS solutions the addition of stannic oxide decreases the foam volume and residual ABS concentration, producing a pronounced increase in the enrichment ratio.
Effect of packing on the catalytic isomerization of cyclopropane in fixed and fluidized beds
Authors: Ishii Tadao , Osberg G. L. 
Published: June 2004

AbstractAn experimental study with fixed and fluidized beds in the isomerization of cyclopropane on a silica alumina catalyst is reported for a temperature range of 150° to 250°C. and of 5 to 150 W/F (g‐catalyst, hr./g.‐mole). The effects of various cylindrical screen packing, 0.2‐, 0.4‐, and 1.0‐in. diameter, and 1.0‐in. diameter pall ring, on final conversion were determined. Reactor scale effects were also considered with reactors of 0.9‐, 1.8‐, and 6.0‐in. diameter and bed heights 1.8 to 11.0 in.Overall conversions were higher in a fluidized bed with packing than in a normal fluidized bed but were less than in a fixed bed, though approaching it in some cases. Rate data from the fixed bed closely followed first‐order kinetics. When the same catalyst was tested in a normal fluidized bed, the rate was dependent on linear gas velocity and catalyst bed height. With packing present in the fluidized bed, this dependency was much less, but packing size and shape had some effect.Several previously proposed reactor models were considered for correlating the data.
On stress‐relaxing solids: Part III. Simple harmonic deformation
Authors: Vela Saul , Kalb J. W. , Fredrickson A. G. 
Published: June 2004

AbstractThe viscoelasticity of a number of polymer solutions was studied by subjecting the solutions to simple harmonic displacements in a pipe. Both water‐based and organic‐based solutions were used. Results were analyzed in terms of a modification of the operator equation of linear viscoelasticity. A three‐constant model used earlier was found to correlate most of the data. Further experiments to verify the model are suggested.
The prediction of the viscosity of multicomponent, nonpolar gaseous mixtures at atmospheric pressure
Authors: Strunk Mailand R. , Fehsenfeld Gary D. 
Published: June 2004

AbstractThe method for predicting the viscosity of binary nonpolar gaseous mixtures from pure component Lennard‐Jones force parameters and composition has been extended to multicomponent mixtures. The 136 mixtures examined contained from three to seven components from sixteen different gases in the temperature range from 5° to 1,014°C. The predicted gaseous viscosities should fall between −0.3 and −6.7° of the actual viscosities 95% of the time. With a slight modification of the constant in the viscosity expression, the viscosity can be predicted to within ±3.2% of the experimental viscosity 95% of the time for mixtures containing three or more components.
Stagnation in a fluid interface: Properties of the stagnant film
Authors: Merson R. L. , Quinn J. A. 
Published: June 2004

AbstractThe mechanism whereby surface‐active agents cause stagnation in a fluid interface has been extensively studied for water flowing in a horizontal channel. Known surface‐active contaminants exhibiting varied surface behavior were added to the water. Distinctly different phenomena were observed with compressible and incompressible films.
Films of non‐Newtonian fluids adhering to flat plates
Authors: Gutfinger Chaim , Tallmadge John A. 
Published: June 2004

AbstractThis paper presents a study of flux, film thickness, and velocity profiles in the drainage and withdrawal processes of non‐Newtonian fluids on flat plates. The flow equations for the drainage from a vertical plate are solved for a three‐constant or Ellis model fluid. The solution is compared with that of the Newtonian fluid.The withdrawal case is solved for the power law fluid. The solution consists of matching of the equation of capillary statics in the liquid bath to the flow equation in the entrained film. Experimental data of coating of an endless belt with a film of a non‐Newtonian fluid are presented and discussed in view of the theory developed.
Bounded and patched solutions for boundary value problems
Authors: Churchill Stuart W. 
Published: June 2004

AbstractThe technique of bounding, that is of constructing general solutions for all ranges of the variables and parameters from solutions for a few limiting and special cases, is outlined and illustrated for problems in conduction and convection. The technique of patching, that is of constructing approximate solutions for multiphase media by the combination of pseudo solutions for the different regions, is also outlined and illustrated for problems in conduction and freezing. The shortcomings and possible inaccuracies of these two techniques are indicated as well.
Significance of pressure gradients in porous materials: Part I. Diffusion and flow in fine capillaries
Authors: Wakao Noriaki , Otani Seiya , Smith J. M. 
Published: June 2004

AbstractEquations are derived for the effect of a total pressure gradient on flow and diffusion of a binary gas system in a fine capillary. The results apply over the pressure and pore radius regimes from Knudsen flow to Poiseuille flow.Application of the equations to a pure component leads to an expression for the permeability which predicts the observed minimum flow in the slip‐flow region. This expression agrees well with Knudsen's data for carbon dioxide and for new measurements for nitrogen in a glass capillary (radius = 0.01244 cm.).
The stability of nonlinear systems in the region of linear dominance
Authors: Gura I. A. , Perlmutter D. D. 
Published: June 2004

AbstractA technique has been developed for finding quantitative regions of asymptotic stability for nonlinear systems by using a known proof of the theorem which substantiates the linearization. In a sense, the method defines a region in which the first‐order approximation is dominant from the point of view of stability. While the computations necessary can be somewhat involved, the procedure is essentially identical in all situations, and once established, can easily be used for a vast class of autonomous systems. The practical problems of both reversible and irreversible chemical reactions occuring in a continuous flow stirred vessel have been analyzed. Stability regions were obtained which are sufficiently extensive to be practical from the process viewpoint.
Local rates of mass transfer from spheres in ordered arrays
Authors: Rhodes John M. , Peebles Fred N. 
Published: June 2004

AbstractThe local mass transfer rates from a sphere in a regular packing array have been determined by measuring the local radius change of a slightly soluble 1.500‐in. diameter benzoic acid test sphere after having been immersed in a water stream. Results in the form of typical local Sherwood number profiles are reported for single spheres over a particle Reynolds number range of 166 to 1,560, and for spheres in simple cubic packing and rhombohedral packing over particle Reynolds number ranges of 488 to 2,409 and 1,680 to 3,410, respectively. All runs were made at room temperature. An idealized flow pattern around spheres in simple cubic packing is presented.
Forced convection mass transfer: Part I. Effect of turbulence level on mass transfer through boundary layers with a small favorable pressure gradient
Authors: Thomas David G. 
Published: June 2004

AbstractThe effect of free stream turbulence level on forced convection through laminar and turbulent boundary layers on a flat was studied in a wind tunnel with a small but nonzero favorable pressure gradient by means of the naphthalene sublimation technique.With the small favorable pressure gradient used in this study, the rate of forced convection through laminar boundary layers agreed with Polhausen's theoretical equation for turbulence levels less than 2.8% but increased in a regular fashion for turbulence levels greater than 2.8% and was almost tripled at a free stream turbulence level of 11%. There was no evidence of an interaction between pressure gradient and turbulence level which would produce disproportionate effects on the rate of forced convection through laminar boundary layers. Substantially no effect of turbulence level on forced convection through turbulent boundary layers was observed for turbulence levels up to 7%.
Unsteady state gas‐liquid slug flow through vertical pipe
Authors: Street James R. , Tek M. Rasin 
Published: June 2004

AbstractMacroscopic mass and momentum balances have been used to predict the unsteady behavior of gas‐liquid slug flow through vertical pipe. Equations have been developed to predict the time‐dependent pressure drop along the pipe as well as the time‐averaged pressure drop. The results of the analysis indicate that the gas bubble lengths and frequencies of generation must be known before the pressure drop can be predicted as a function of time. In this work the bubble generation was specified in two ways: by experimental measurement of the bubble lengths and frequencies of generation from an optical technique developed for this purpose, and by assuming a periodic generation of gas bubbles of uniform length. The comparisons between predicted and measured pressure drops (both time dependent and time averaged) are satisfactory and appear to support the theoretical model. An extension of the results obtained in light of the published information on solid‐gas and immiscible liquid‐liquid systems in slug flow permits the introduction of generalized concepts of slug flow behavior in two‐phase systems.
The self‐diffusivity of substances in the gaseous and liquid states
Authors: Mathur G. P. , Thodos George 
Published: June 2004

AbstractRelationships applicable for the prediction of self‐diffusivities of gases and liquids have been developed from available experimental values and an application of dimensional analysis. Separate relationships were found to apply for gases at normal pressures and for gases at elevated pressures. For the liquid state a different dependence on the conditions of temperature and pressure was observed and was taken into account to develop the relationship for this state of aggregation.
Effectiveness factors in a nonisothermal reaction system
Authors: Cunningham R. A. , Carberry J. J. , Smith J. M. 
Published: June 2004

AbstractHydrogenation rates of ethylene on a copper‐magnesium oxide catalyst were measured for fine catalyst particles and ½ in. spherical pellets from 60° to 160°C. Experimental effectiveness factors for this exothermic reaction system ranged from 0.2 to 25, depending upon the temperature and density of the catalyst pellets. The activation energy for the particles was 11,800 cal./g. mole (above 120°C.), while E for the pellets decreased to zero at high temperatures. Reasons for this behavior are discussed.The effective thermal conductivity of the catalyst pellets was measured as a function of density and the effective diffusivity was estimated from pore size and pore volume measurements. In principle this information and the rate data for the particles are sufficient to predict effectiveness factors for the pellets. However available prediction methods are based upon first or second order rate equations which do not fit the ethylene hydrogenation reaction.
Thermal conductivity measurements for nitrogen in the dense gaseous state
Authors: Misic Dragoslav , Thodos George 
Published: June 2004

AbstractA coaxial cylindrical type of cell was designed and constructed for the measurement of the thermal conductivity of gases at high pressures and moderate temperatures. This cell was used to establish the thermal conductivity of nitrogen for pressures up to 4,625 lb./sq.in.abs. and for temperatures of 22.2° and 50.5°C. The resulting thermal conductivity values were found to be in agreement with values reported in the literature for nitrogen at these elevated pressures. These experimental measurements indicate that the cell developed for this investigation is capable of producing reliable thermal conductivities for gases at high pressures.
Heat transfer in a round tube with sinusoidal wall heat flux distribution
Authors: Hsu Chia‐Jung 
Published: June 2004

AbstractSufficiently accurate values of first twenty eigenvalues, eigenfunctionsRn(1), and the coefficients for series expansion, as well as asymptotic expressions for these quantities, have been obtained for heat (or mass) transfer to fully developed laminar flow inside a round tube with uniform wall heat (or mass) flux. The first ten eigenfunctions are shown graphically for the radius range 0 ≤r/ro≤ 1.These quantities are used to calculate the Nusselt numbers for sinusoidal wall heat flux distribution and are compared with the corresponding slug flow Nusselt numbers.
Freezing front motion and heat transfer outside an infinite, isothermal cylinder
Authors: Tien L. C. , Churchill S. W. 
Published: June 2004

AbstractA numerical method is developed for calculation of the temperature field in a material that freezes outside an isothermal cylinder. Numerical values are presented for the freezing front location and for the rate of heat transfer to the cylinder. The computed values are compared with the analytical solutions for the limiting cases of zero latent hear, negligible heat capacity, and freezing adjacent to a flat plate. The results have many applications, including the freezing of wet soil outside underground pipes or storage tanks for cryogenic fluids.
Ion flotation of dichromate with a cationic surfactant
Authors: Grieves Robert B. , Wilson Thomas E. , Shih Kenneth Y. 
Published: June 2004

AbstractAn experimental investigation is presented of the flotation of dichromate ion from aqueous solution with a cationic surfactant, ethylheaxadecyldimethylammonium (EHDA) bromide. Dichromate forms a colloidal complex with EHDA ion in a molar ratio of approximately 1 : 2. Excess surfactant causes the formation of a stable foam to which the complex is adsorbed, providing the separation of dichromate from aqueous solution. Batch flotation studies were conducted utilizing approximately 2‐liter solutions containing from 10 to 200 mg. of dichromate ion (4.8 to 96.3 mg. of hevavalent chromium), with masses of EHDA‐Br ranging from 400 to 800 mg. The effects of mass of surfactant added, dichromate concentration, pH, and possible interfering anions were determined. A comparison is made with pure surfactant solutions, and the mechanism of the process is discussed.Most efficient operation is achieved with a molar feed ration of EHDA ion to dichromate ion from 2.1 to 3.0, and removal ratios ranging from 80 to 95% are obtained. Reduction of the residual dichromate below 10% of the feed concentration requires additional surfactant and produces excessive foam, which could be overcome by modifications in operating conditions.
Mass transfer at high mass fluxes: Part I. Evaporation at the stagnation point of a cylinder
Authors: Mendelson Harvey , Yerazunis Stephen 
Published: June 2004

AbstractAn experimental method for measuring mass transfer rates at high mass fluxes is developed for the case of evaporation at the stagnation point of a cylinder. Evaporation of carbon tetrachloride at the stagnation point was measured and determined to be consistent with theoretical predictions. It was observed that water exhibits a significant interfacial resistance to evaporation at high transfer rates. Evaporation coefficients based on the discrepancy between experimental determinations and theoretical expectations were found to be a strong function of temperature and to be consistent with the majority of reported measurements made at lower temperatures. The experimental method should be useful for application to other configurations and flow conditions for studying mass transfer at high mass fluxes.
An eddy viscosity model for friction in gas—solids flow
Authors: Julian F. M. , Dukler A. E. 
Published: June 2004

AbstractThe equations normally used to predict velocity distribution and eddy viscosity in single‐phase flow systems can be adapted to fit gas‐solids flow systems by including a term to account for the quantity of solid matter carried by the gas stream. This solids loading is expressed as pounds of solid per pound of gas. These modified equations can then be used to calculate the pressure drop of a solids‐laden gas stream flowing in a pipe by means of a two‐phase friction factor. Comparison of this approach with available pressure drop data is used to check its validity and to evaluate the constants in the equations.
Phase equilibria for strongly nonideal liquid mixtures at low temperatures
Authors: Eckert C. A. , Prausnitz J. M. 
Published: June 2004

AbstractInvestigation of the nonideal behavior of mixtures of simple molecules is an important step toward improved understanding of the theory of solutions. This work describes an equilibrium apparatus suitable for the measurement of vapor‐liquid and vapor‐liquid‐liquid equilibria of simple fluid mixtures at cryogenic temperatures. Vapor‐liquid data are reported for the argonethane and nitrogen‐carbon tetrafluoride systems. Contrary to expectations, limited liquid‐phase miscibility was not observed for either of these mixtures. These results and those for other nonideal mixtures of simple molecules are compared with predictions of upper critical solution temperatures by the theory of regular solutions. Usefulness of this theory is impaired by its neglect of the order‐disorder phenomenon and, more seriously, by the geometric‐mean assumption for the intermolecular forces between dissimilar molecules.
Interaction model for critical temperatures of multicomponent mixtures of methane‐free aliphatic hydrocarbons
Authors: Ekiner Okan , Thodos George 
Published: June 2004

AbstractA mathematical treatment based on an interaction model has yielded an expression capable of establishing the critical temperatures of multicomponent aliphatic hydrocarbon mixtures. This model postulates an infinite‐series expansion for the difference between the actual critical temperature and its corresponding pseudocritical value. For methane‐free aliphatic hydrocarbon mixtures, this infinite series has been truncated beyond the third‐order interactions. Explicit relationships are given for the second‐order interaction coefficientsAijandBijas a function of the binary‐system parameter τijand the third‐order interaction coefficient βijkas a function of χijk, the ternary‐system parameter.This interaction model has been applied to one hundred‐sixteen different compositions of binary, ternary, quaternary, and quinary aliphatic hydrocarbon systems to produce an overall average deviation of 0.35%. Owing to the different interaction behavior of methane, systems containing methane have not been included in this study.
Mathematical models for mass transfer accompanied by reversible chemical reaction
Authors: Huang Chen‐Jung , Kuo Chiang‐Hai 
Published: June 2004

AbstractBased on the film‐penetration theory, the film theory, and the surface renewal theory, theoretical equations are obtained for the rate of interphase mass transfer accompanied by a first‐order reversible reaction. The film‐penetration theory is again found to be the more general concept and the other two theories are merely the limiting cases of the film‐penetration theory. The rate equation based on the film‐penetration theory can also be reduced to those obtained by other investigators on the basis of simpler postulations.Contrary to the previous findings in other chemical mass transfer systems, it is found that the predicted effects of chemical reaction on the overall mass transfer rate are indeed sensitive to the theory or the model adopted in postulating the mechanism. One exception to this is when the diffusivities of the reactant and the product are nearly equal. For this special case, the three theories predict practically the same effects of a reversible reaction.An approximate rate equation is proposed for mass transfer with a high order reversible reaction. When the forward reaction is very rapid, the reaction rate constants become insignificant variables and the mass transfer rate is a simple function of the diffusivity ratio, the concentration ratio, and the order of reaction.