bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corresponding states: I. Theoretical development for mixtures
Authors: Gunn Robert D. 
Published: June 2004

AbstractPart I of this work develops a corresponding states theory for fluid mixtures. A greater predictive capability for the thermodynamic properties of mixtures is achieved through three developments: 1. The theretical validity of the pseudocritical method is established. 2. The theory is founded on well‐defined assumptions. 3. The composition dependence of the scaling parameters (pseudocritical constants) is developed from rigorus mixing rules. Implementation of the new method is discussed in Part II.
II. Prediction of component fugacities and related properties of mixtures
Authors: Leyendecker W. R. , Gunn R. D. 
Published: June 2004

AbstractA computer program based on the theory of Part I is developed for calculating equilibrium ratios and related thermodynamic properties of mixtures, and a variety of data are used to test the method. For the carbon dioxide‐n‐butane system both liquid and gaseous compressibility factors are predicted with an average absolute deviation from experimental values of 1.3% for a wide range of conditions. A maximum deviation of 5.4% occurs in the critical region. Derivative properties such as component fugacities and equilibium ratios show somewhat larger deviations as expected. For the same system average deviations are 2.7% for carbon dioxide fugacities, 2.6% for n‐butane fugacities, and 3.3% for carbon dioxide and n‐butane equilibrium ratios. Average deviation for predicted equilibrium ratios for eight binary systems and 574 data points is 4.6%. Equilibrium ratios for two ternary systems are also predicted accurately. The major advantage of the method, however, is the small or negligible amount of experimental mixture data required. The method has not been tested below a mixture reduced temperature of 0.8, the lower limit of the Pitzer tables. Without density corrections to the scaling parameters best results are obtained if all binary pairs in a mixture fall within range 0.25 <VCj TCj/VCi TCi < 4.0.
Foam separation of complex anions: Silver thiosulfate
Authors: Bhattacharyya Dibakar , Grieves Robert B. 
Published: June 2004

AbstractAn experimental study is conducted of the ion flotation of Ag(S2O3)– and Ag(S2O3)23– from an aqueous solution at pH 4.5 with a cationic surfactant. For initial solutions 2.0 × 10−3 to 8.0 × 10−3 M in total silver, optimum silver flotation at foam cesssation is achieved at a molar thiosulfate to silver ratio (Th/Ag) of 0.75 and surfactant to silver ratio (EHDA/Ag) of 0.5, at Th/Ag = 1.0 and EHDA/Ag = 1.1, and at Th/Ag = 2.0 and EHDA/Ag = 2.2. The silver flotation is 99+, 98+, and 92+ % at the three sets of ratios, respectively. At Th/Ag > 2.0, highly efficient flotation cannot be achieved due to decreased particle size, and perhaps by competition with free S2O32− for the surfactant.The stoichiometry of the ion flotation product is established from relative silver and surfactant flotation rates. The stoichiometry is independent of foaming time, but is a strong linear function of EHDA/Ag and Th/Ag, in contrast to the stoichiometry of flotation products of other simple and complex anions. Rate data can be fit reasonably by a first‐order reversible model. The rate constant is an inverse function of EHDA/Ag, indicating the desirability of pulsed surfactant addition. Results are discussed in terms of the average ligand number of silver, particle size, and surface potential measurements.
A theoreticol and experimental study of the centrifugal molecular still
Authors: Greenberg David B. 
Published: June 2004

AbstractA mathematical model of the centrifugal molecular still has been derived based on a fully developed profile, but negligible normal and tangential velocity components. Thermal gradients, film thicknesses, and evaporation rates calculated from this mathematical expression correlate well with reported literative values as well as with the present data.Mean distillation rates were measured for five pure liquids on a centrifugal still with an effective evaporating surface area of 100 sq. cm. These experimentally obtained rates for liquids exhibiting ideal behavior agreed quite well with theoretical values predicted on the basis of simple kinetic theory. In the case of an associated liquid, however, rate measurements were found to be only 53 to 90% of the theoretical value. Although these low values tend to support the concept of an evaporation coefficient as a true molecular property, there wasevidence that surface irregularities could have accounted for all or at least part of the discrepancy noted.
Activity coefficients of strong electrolytes in multicomponent aqueous solutions
Authors: Meissner H. P. , Kusik C. L. 
Published: June 2004

AbstractThe quantity T12 here called the reduced activity coefficient is related to Γ12 the mean activity coefficient of a strong electrolyte 12 as follows:

where z1 and z2 are the charge number on the ions. The value of Γ12 for electrolyte 12 in an aqueous solution containing the three ions 1, 2, and 3, such as Na+ Cl− and Ba++, is to be calculated as follows:

Here Γ°32 and Γ°12 are for the indicated electrolytes, namely NaCl and BaCl2 in this example, at the total ionic strength of the mixture. The term X3 represents the fraction m3z32/(m1z12 + m3z32) in which m represents the molality of the indicated ion. Fair success is usually attained with this equation in predicting γ, even at high electrolyte concentrations.Similar equations are proposed for aqueous solutions containing four or more ions.
On the computation of complex equilibria
Authors: Ma Y. H. , Shipman C. W. 
Published: June 2004

AbstractA method is described for solving the problem: given fixed pressure, temperature, the amounts of the chemical elements, and the chemical potentials of possible chemical species at the pressure and temperature specified, determine the equilibrium composition. The method requires a minimum of judgment on the part of the user.A modification of Naphtali's method for direct minimization of Gibbs' function provides an estimate of the composition of sufficient accuracy to insure convergence of solution, by the Newton‐Raphson method, of the nonlinear equations describing the equilibrium.Problems in treating multiple phaes of unknown stability and chemical species present in small amouts are handled by ignoring unstable phases and small quantitites in the direct minimization until the amounts of the major consitituents have been at least approximately determined. To accomplish this, species temporarily ignored are assigned a ficitious mol fraction so that their re‐entry into the calculation can be established. Truncation errors in the direct minimziation can be tolerated because of the two‐step method.Examples of some of the problems solved are given.
The peak pool boiling heat flux from a sphere
Authors: Ded Jagjit S. , Lienhard John H. 
Published: June 2004

AbstractA hydrodynamic prediction is formulated for the peak nucleate boiling heat flux on spheres. It employs no empirical constants but it is justified by an experimental correlation of the vapor blanket thickness at the equator of the sphere. The prediction compares very favorably with 27 original data obtained by the transient calorimeter method in both water and N2 on spheres of different sizes. It also compares well with the data of prior investigators for a large range of size, gravity, and boiled liquids. Assumptions as to the vapor removeal configuration are supported with photographic observations of the boiling procss.
Forced convection heat transfer correlations for flow in pipes, past flat plates, single cylinders, single spheres, and for flow in packed beds and tube bundles
Authors: Whitaker Stephen 
Published: June 2004

AbstractPreviously obtained experimental heat transfer data have been collected and are illustrated along with minor variations of the standard correlations. Analysis of data for heat transfer in randomly packed beds and compact (void fraction less than 0.65) staggered tube bundles indicates that the Nusselt number for a wide range of packing materials and tube arrangements is given by

provided NRe ≥ 50. The correlations presented in this paper are not necessarily the most accurate available; however, they have wide application, are easy to use, and are quite satisfactory for most design calculations.
Laminar tube flow through an abrupt contraction
Authors: Christiansen E. B. , Kelsey S. J. , Carter T. R. 
Published: June 2004

AbstractThe general equations of motion were solved numerically for the laminar isothermal flow of Newtonian fluids from a large tube of circular cross section through an abrupt contraction into a coaxial tube of smaller diameter and through the flow‐development region of the smaller tube. The ratio of the diameter of the large tube to that of the smaller tube was varied from one to eight (the latter in one case). Solutions were obtained for the case where the larger tube is real, with no slip at the wall, and for the case where it is a frictionless “stream” tube. The results are presented as charts giving excess pressure losses attributable to contracted and developing flow in terms of equivalent smaller‐tube diameters as functions of the tube‐contraction ratio and the Reynolds number, which was varied from 0.01 to as high as 500 in one case. Both radial‐ and axial‐velocity profiles are presented. The computed results are shown to be in satisfactory agreement with some experimental data. The results are presented in a manner convenient for use in the design of equipment in which contracted Newtonian flow occurs, such as fiber spinnerettes and heat exchangers, and in the analysis of experimental data for contracted flow.
Prediction of breakthrough curves in packed beds: II. Experimental evidence for axial dispersion and intraparticle effects
Authors: Jeffreson C. P. 
Published: June 2004

AbstractThe effects of axial fluids dispersion on breakthrough curves in packed beds is considered and formulae are derived for ‘F‐factors’, which allow heat transfer coefficients obtained by step testing to be corrected for axial fluids dispersion. A comparison of steady state and unsteady correlations for heat transfer in packed beds suggests that axial dispersion effects are incorporated in certain steady state heat transfer correlaions. Further correction would thus lead to errors in breakthrough curve prediction. Experimental data for breakthrough curves in packed beds of highly conductive and poorly conductive spheres is examined and Biot number correction factor 1 + Bi/5 shown to be valid for Biot numbers up to about 4.
Residence time and fluid mixing on commercial scale sieve trays
Authors: Bell Richard L. 
Published: June 2004

AbstractA fiber optic technique was used to obtain point residence time distributions at several points on an 8 ft. diam. sieve tray in hydrocarbon service. Residence time patterns were obtained over a wide range of vapor and liquid loadings with the isopropyl alcohol–water system and at both ends of the cyclohexane toluene system. The data reveal severe flow nonuniformities on the tray including nonuniform velocity distribution and retrograde flow near the column walls. The reasons for this behavior are discussed.
Kinetics of reduction of nickel oxide with CO
Authors: Krasuk J. H. , Smith J. M. 
Published: June 2004

AbstractInitial rates were measured for the reduction of single pellets of nickel oxide with carbon monoxide at atmospheric pressure and temperatures from 566 to 796°C. The nickel oxide pellets were porous (ϵ0 = 0.032 − 0.35) and intrapellet diffusion retarded the rate so that the shrinking core model was not applicable. Effective diffusivities for the lower porosity pellets were very small, corresponding to tortuosity factors of about 180 for ϵ0 = 0.032 and 92 for ϵ0 = 0.062.The reaction appeared to be first order in carbon monoxide. Rate constants, based upon the intraparticle area, indicated an activation energy of 47 kcal/g.‐mole over the temperature range 566 to 682°C. At higher temperatures the rate was constant. These results, while not conclusive, are in agreement with a reaction sequence consisting of formation of nuclei of nickel atoms in the nickel oxide surface, rapid adsorption of carbon monoxide at the nickel‐nickel oxide interface, migration of the adsorbed carbon monoxide to the adjacent lattice, and a slow reaction to extract oxygen from the lattice.
Volatiles retention during drying of food liquids
Authors: Chandrasekaran Santosh K. , King C. Judson 
Published: June 2004

AbstractThe retention of trace volatile components in food liquids during low temperature drying processes is analyzed through a ternary diffusion model. Flux equations for both water and trace organic components are solved numerically for typical drying situations. Several effects are found with the ternary analysis which are not evident from a simpler binary model. The sugar‐water composition gradient which develops during drying causes an appreciable transport of the trace volatile species. This transport can occur in the same direction as the transport resulting from the concentration gradient of the volatile species, or in the opposite direction, and can result in a local accumulation of the volatile species. Concentration profiles for both water and dilute volatile components were experimentally measured during nearly isothermal drying of gelled slabs of synthetic sugar solutions and natural fruit juice concentrates. The predicted internal maximum in volatiles concentration is borne out by the experiment, and a satisfactory agreement of observed with predicted volatiles retention is found, within the limits of the experiment.
An efficient algorithm for optimum decomposition of recycle systems
Authors: Upadhye Ravindra S. , Grens Edward A. 
Published: June 2004

AbstractA method is developed for decomposition of a recycle process so as to minimize the summation of weighting factors for variables torn. This procedure is based on application of dynamic programming to a state space representing combinations of cycles opened. The resulting algorithm is well suited to machine implementation and is more efficient for large problems than alternative procedures that also guarantee decomposition.
Penetration characteristics of a submerged steam jet
Authors: Kerney P. J. , Faeth G. M. , Olson D. R. 
Published: June 2004

AbstractAn experimental investigation was made of the lenght of the turbulent vapor cavity formed by a steam jet discharging into a subcooled liquid water both. The experiments considered both constant area and convergent‐divergent steam injectors of various external geometries. The tests were conducted with the bath at atmospheric pressure, bath temperatures in the range 301–358K, injector exit diameters in the range 0.00040–0.0112 m, for choked injector flows having mass velocities in the range 332–2050 kg/m2.s. These conditions yielded injector exit Reynolds numbers from 2 to 150 × 104. Over this range a correlation was developed to yield the length of the vapor cavity as a function of the injector diameter, exit mass velocity, and a driving potential for the condensation process. The heat transfer coefficients for this condensation process were found to be significantly greater than those encountered in turbulent film condensation processes in the vicinity of tubes and walls.
The role of porosity in filtration VIII: Cake nonuniformity in compression–permeability cells
Authors: Tiller Frank M. , Lu Wei‐Ming 
Published: June 2004

AbstractCompression‐permeability cells are utilized for measurement of porosity and permeability of compressible cakes. Shortcomings of the cells have tended to be minimized in the literature. Data are presented which show that the stress distribution in typical C‐P cells is highly nonuniform because of wall friction. For compressible materials, the porosity and permeability would also be nonuniform. Use of large L/D ratios and minimizing wall friction are essential to proper use of C‐P cells.
The effect of gibbs adsorption on marangoni instability in penetration mass transfer
Authors: Brian P. L. T. , Ross J. R. 
Published: June 2004

AbstractA theoretical analysis of Marangoni convection in gas‐liquid mass transfer shows the stabilizing effect of surface convection in the Gibbs adsorption layer. Results are obtained for various ratios of liquid layer thickness to mass transfer penetration depth. For deep liquid layers, complete stabilization results when the inventory in the Gibbs layer equals the solute deficiency in the liquid phase boundary layer, irrespective of the shape of the unperturbed concentration profile.This new theory agrees much better with experimental results than did previous theories. For example, for triethylamine desorption from water, the discrepancy is reduced from a factor of 8,000 to a factor of 8. Speculations are offered concerning this residual discrepancy.
A study of inversion curves
Authors: Juris Kenneth , Wenzel L. A. 
Published: June 2004

AbstractA comparative study has been made on the predictive capabilities of a number of the more popular equations of state in use today. The equations were compared in their ability to predict the locus of points for which the Joule‐Thomson coefficient is zero, the inversion curve.The prediction of an inversion curve is an extremely severe test of an equation of state. To date inversion curves have been calculated only for the Van der Waals, Dieterici, Lennard‐Jones and Devonshire, and DeBoer‐Michels equations of state. This study covers the Van der Waals and Dieterici equations as well as the Virial, Berthelot, Redlich‐Kwong, Beattie‐Bridgeman, Benedict‐Webb‐Rubin, and Martin‐Hou equations of state.The results of the investigation show, among other things, that the Redlich‐Kwong equation is quite unusual in that it predicts the inversion locus with more accuracy than any of the much more complex equations of state. Its predictive capabilities extend into the liquid region.
Gas‐liqud slug flow with drag‐reducing polymer solutions
Authors: Rosehart R. G. , Scott D. S. , Rhodes E. 
Published: June 2004

AbstractThe two‐phase slug flow regime in horizontal cocurrent gas‐liquid flow was studied for the case of the liquid phase containing small amounts of polyacrylamide, a drag‐reducing long chain polymer. The experimental work was performed in a 2.54 cm I.D. horizontal test section 10.7 m long.Results indicated that two‐phase drag reduction was greater than in single phase flow at the same superficial liquid velocities. By the use of pressure drop results with and without polymer additive, and a knowledge of slug geometry, frequency, and velocity, it was possible to separate approximately the contribution to the pressure drop of liquid wall friction and slug intertial effects. In all cases, the acceleration term was important and is the major energy term at most flow conditions. The technique may be of general usefulness in determining accelerational effects in two phase flows.When drag reducing agents have been added to a horizontal slug flow, the pressure loss can be correlated successfully both by the Lockhart‐Martinelli type of relationship or by a universal drag reduction curve of the type proposed by Virk.
Thermodynamics of multi‐solute adsorption from dilute liquid solutions
Authors: Radke C. J. , Prausnitz J. M. 
Published: June 2004

AbstractThe thermodynamics of ideal dilute solutions is applied toward establishing a method for predicting multi‐solute adsorption using only data for single‐solute adsorption from dilute liquid solution. The method is similar to that proposed by Myers and Prausnitz for adsorption of gas mixtures.Experimental adsorption data for activated carbon at 25°C are reported for dilute aqueous solutions containing acetone and propionitrile, and p‐chlorophenol and p‐cresol. Calculated and experimental results are in excellent agreement for the first system and in fair agreement for the second system. It appears that the ideal dilute‐solution theory for predicting multisolute adsorption is most reliable for those systems where solute adsorption loading is moderate. When solute adsorption loading is large, the simplifying assumptions in the theory must be relaxed to allow for solute‐solute interactions on the surface. The method presented here is simple to use and provides good approximations for engineering design.
The retention of large particles in fibrous filters
Authors: Freshwater D. C. , Stenhouse J. I. T. 
Published: June 2004

AbstractThe inertial interception mechanism of particle‐fiber collision in fibrous filters is described. The main mechanisms by which particles are retained in filters together with the effect of a number of operating parameters are discussed. The effect of particle size, gas velocity, relative humidity, and filter loading on the retention efficiency of large particles (> 5μ) is investigated experimentally.
Counterdiffusion of liquid hydrocarbons in type Y zeolite: Effect of molecular size, molecular type, and direction of diffusion
Authors: Moore Rebecca M. , Katzer James R. 
Published: June 2004

AbstractThis paper presents experimental results on the counterdiffusion of liquid hydrocarbons in the Y zeolite as determined by an unsteady state technique using the zeolite powder. The critical diameter of aromatic molecules counterdiffusing with respect to cyclohexane into NaY zeolite has a marked effect upon the counterdiffusion rate. For a given molecular type, the single parameter of critical molecular diameter correlates the size effect well. Molecular type, for example, toluene vs. phenol, also has a pronounced effect on the counterdiffusion rate. Those molecules showing stronger interactions with the zeolite have lower counterdiffusion rates. In both NaY and SK‐500, the diffusion coefficients for adsorptive counterdiffusion are an order of magnitude greater than the diffusion coefficients for desorptive counter‐diffusion indicating that factors other than simple intracrystalline diffusion as such are also important in zeolite counterdiffusion. Simple diffusion models do not account for the differences observed indicating that a more sophisticated approach is necessary.
Calculation of multicomponent liquid‐liquid equilibrium with Renon's and Black's activity equations
Authors: Guffey Charles G. , Wehe Albert H. 
Published: June 2004

AbstractThe combination of optimization theory and thermodynamics was used to develop a fast, reliable computerized procedure for predicting or representing multicomponent liquid‐liquid phase equilibrium. Both the Renon and Black activity coefficient equations were compared with experimental data using the procedure. Experimental data for three quarternary systems from the literature were examined. Prediction of ternary data from binary data is not very reliable, although ternary data can nearly always be represented by adjustment of the predicted binary constants. Quarternary data can be predicted from accurate ternary representations of similar species provided the additional compound is from the same family group. The Renon equation is recommended rather than the Black equation.
Protein ultrafiltration: A general example of boundary layer filtration
Authors: Kozinski A. A. , Lightfoot E. N. 
Published: June 2004

AbstractA rotating disk membrane was developed to investigate experimentally concentration polarization during the ultrafiltration of bovine serum albumin solutions. The experimental data supported analytical and numerical predictions which were developed as part of this study. Osmotic pressure and concentration dependent viscosity and diffusivity were demonstrated to be important tactors. The results were also extended to predict ultrafiltration in porous walled ducts. Finally, a formal description of protein ultrafiltration in terms of the Stephan‐Maxwell flux equations was shown to provide a unifying description of all filtration processes from mechanical filtration to reverse osmosis.