bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐diffusion and viscosity of some liquids as a function of temperature
Authors: Ertl H. , Dullien F. A. L. 
Published: June 2004

AbstractSelf‐diffusion coefficients of 15 liquids have been measured as a function of temperature between their melting and boiling points. The systems investigated were the benzenes, C6H5X where X = H, F, Cl, Br, and I, n‐paraffins, CnHn + 2 where n = 7, 9, 10, 12, 14, 16, and 18, acetone, acetic acid and water. The pulsed nmr technique was employed for the diffusion measurements. In addition, the viscosities of the halogenated benzenes have been measured between 20°C and their melting points.The diffusion results obtained in this study have been found in excellent agreement with the best values available for benzene (Collings and Mills, 1970) and water (Longworth, 1960). The relation between the apparent molecular diameter d (d = 2.24(η VD/RT)1/2) and the critical volume as suggested by Dullien (1972) has been extended to include the temperature dependence of d. It is also shown that the temperature dependence of d is similar for all liquids studied here with respect to the reduced temperature. The increase of d for Tr < 0.46 shows the invalidity of the Stokes‐Einstein relation for this temperature range (Tr = T/Tc).A normalized plot of d has been found very useful in checking the consistency of viscosity and self‐diffusion data. The relations proposed in this work can be used to predict self‐diffusion coefficients and viscosities over the normal liquid range.
On meeting the provisions of the clean air act
Authors: Kyan Chwan P. , Seinfeld John H. 
Published: June 2004

AbstractA general structure is proposed for determining a set of long‐term (multi‐year) source control measures which achieve specified levels of air quality for an airshed at least cost. Such a structure is useful in evaluating alternative air pollution abatement strategies from the standpoint of air quality and total cost. The theory is applied to the problem of evaluating sets of control actions over the period 1973‐1975 in Los Angeles. Costs of achieving various levels of air quality in Los Angeles over this period are determined.
Molecular oxygen induced crystallite size effect in reduction of nitric oxide with ammonia ober supported platinum
Authors: Pusateri Robert J. , Katzer James R. , Manogue William H. 
Published: June 2004

AbstractThe effect of changing platinum crystallite size from 2.7 to 15.5 nm on the specific catalytic activity in NO reduction by NH3, with and without added O2, was studied over alumina supported platinum catalysts between 423 and 473°K. In the NO‐NH3 system both specific catalytic activity and selectivity to N2 are independent of crystallite size. In the NO‐O2‐NH3 system the specific catalytic activity of the 15.5 nm crystallites is about six times that of the 2.7 nm crystallites. The NO reduction rate shows dependence on NO to the first power and on NH3 to the one‐half power.
Pore and solid diffusion models for fixed‐bed adsorbers
Authors: Weber Thomas W. , Chakravorti Ranjit K. 
Published: June 2004

AbstractMost models for fixed bed adsorbers have used either the homogeneoussolid or pore diffusion model for the pellets. When the adsorption isotherm is linear, the two models can lead to identical breakthrough curves. The conditions for this equivalence are presented here. It is shown that one of the bulk flow factors that was included in the formulation of one pore diffusion model will be significant only for feedstreams containing a relatively high concentration of adsorbate. The prosity factor of the pore model is shown to be very important, especially as the porosity decreases. The importance of the two diffusional models with respect to the predicted breakthrough curves is demonstrated. For comparable beds, it is shown that the breakthrough curve based on the homogeneous model is delayed with respect to that based on the pore model at early times, regardless of the shape of the isotherm. Finally, the various possible solutions for an irreverisble isotherm are reviewed for each of the models, and a solution is presented for the general case of a pore model with an outside film resistance.
An empirical correlation of second virial coefficients
Authors: Tsonopoulos Constantine 
Published: June 2004

AbstractA new correlation of second virial coefficients of both polar and nonpolar systems is presented. It uses the Pitzer‐Curl correlation for nonpolar compounds, but in a modified form. The second virial coefficient of nonhydrogen bonding compounds (ketones, acetaldehyde, acetonitrile, ethers) and weakly hydrogen bonding compounds (phenol) is fitted satisfactorily with only one additional parameter per compound, which is shown to be a strong function of the reduced dipole moment. Two parameters are needed for hydrogen bonding compounds (alcohols, water), but for alcohols, one parameter has been kept constant and the other expressed as a function of the reduced dipole moment. The extension of the correlation to mixtures is satisfactory, direct, and involves only one coefficient per binary.
Diffusion in synthetic faujasite powder and pellets
Authors: Ma Y. H. , Ho S. Y. 
Published: June 2004

AbstractTransient sorption rates of allene and methylacetylene in synthetic faujasite (Linde 13X) powder and self‐bonded pellets are studied in a constant‐volume, constant‐pressure system at three temperatures. The intracrystalline diffusion coefficients are found to be in the order of 10−11 cm2/s and the activation energy for diffusion is 4.0 kcal/g‐mole.A simple bipore distribution model for transient diffusion in macropores and micropores is presented. It agrees well with the experimental data and quantitatively predicts the macropore diffusion coefficients. The flow in the macropores is found to be in the Knudsen flow regime.
Comparison of parametric pumping with conventional adsorption
Authors: Gregory R. Alan 
Published: June 2004

AbstractA continuous thermal parametric pumping system is compared to a conventional adsorption system with thermal regeneration. Well‐defined mathematical models are used to find the operating conditions which maximize the separation and throughput of each system.Under practical operating conditions, the model equations indicate parametric pumping can process a larger volume feed stream at equivalent separations than conventional adsorption for the solute/adsorbent system studied. At equilibrium conditions equivalent results are obtained but parametric pumping requires more energy.
Drag reduction in the turbulent flow of fiber suspensions
Authors: Vaseleski R. C. , Metzner A. B. 
Published: June 2004

AbstractAn analysis of the velocity profile and pressure drop relationships for turbulent flow of fiber suspensions through smooth tubes was evaluated experimentally over a range of flow rates, tube sizes, fiber concentrations, and fiber geometries (aspect ratios). This work shows that drag reduction in these systems, in marked contrast to that in viscoelastic polymeric fluids, involves processes in the turbulent core of the velocity field. As a result the drag reduction achieved is independent of the scale of the system.The implications of these results with respect to rates of heat and mass transport are considered in a preliminary way. The measurement of such transport rates, and of the turbulent velocity profiles in dilute suspensions, is seen to be of mechanistic interest.
Separation of multicomponent mixtures via thermal parametric pumping
Authors: Chen H. T. , Lin W. W. , Stokes J. D. , Fabisiak W. R. 
Published: June 2004

AbstractA thermal continuous parametric pump for separating multicomponent mixtures was experimentally investigated using the model system tolueneaniline‐n‐heptane on silica gel adsorbent. A simple method for predicting separations is presented and is found to be in good agreement with the experimental results. The method, based on an equilibrium theory, invokes the assumption that a multicomponent mixture contains a series of pseudo binary systems. Each binary system consists of one of the solutes as one component and the common inert solvent as the other component.
Boundary‐layer skimming: Calculational curiosity or promising process?
Authors: Lee Ho‐Lun , Lightfoot E. N. 
Published: June 2004

AbstractIt is suggested that the productivity of ultra‐filtration and reverse osmosis can be increased substantially where the desired product is concentrated in the diffusional boundary layer adjacent to the membrane. This increase can be achieved by removing product preferentially from the boundary‐layer region. The possible concentration increase and yield of such a skimming process are predicted to be very significant for the constant‐property approximation and stagnation flow considered in this exploratory paper.
An experimental investigation of viscous heating in some simple shear flows
Authors: Sukanek Peter C. , Laurence Robert L. 
Published: June 2004

AbstractTheoretical investigations of viscous heating in the flow of fluids with an exponential dependence of viscosity on temperature have shown that, for a given shear stress, two shear rates are possible. Above a critical value, the stress decreases as the shear rate increases.The present work is an experimental study of this phenomenon in plane and circular Couette flows and in cylindrical Poiseuille flow. ArochlorR 1260, a high viscosity Newtonian fluid with an extremely sensitive viscosity‐temperature dependence is used as the test fluid. The results clearly show that two shear rates for Couette flow exist for one measured wall shear stress. Because of the viscosity‐pressure dependence of the fluid, the Poiseuille flow results are inconclusive.
Prediction of transport processes within porous media: Creeping flow relative to a fixed swarm of spherical particles
Authors: Neale Graham H. , Nader Walter K. 
Published: June 2004

AbstractA geometric model for an homogeneous swarm of spherical particles was introduced by us in an earlier paper and successfully employed in a theoretical investigation of diffusive transport processes occurring therein.The same geometric model is used here in a theoretical study of the hydrodynamic transport process occurring within a fixed swarm of spherical particles. The product of the application of this model to the problem of incompressible, creeping fluid flow within an homogeneous swarm of impermeable spherical particles may be regarded as a logical extension of the well‐known Brinkman model; it permits physical representation and rigorous mathematical solution, yielding predictions which are in good agreement with experimental data throughout the entire porosity range. For porosities in excess of 0.7, the predictions agree closely with those obtained by means of Happel's free surface model.
Studies of coalescence and phase separation in thick dispersion bands
Authors: Allak A. M. A. , Jeffreys G. V. 
Published: June 2004

AbstractA refractive index matching technique has been developed to study the behavior and coalescence phenomena of drops in closely packed dispersion bands. The frequency of drop‐drop coalescence has been measured and correlated, and a mathematical model, based on film rupture thickness, has been written for solution by computer to predict dispersion band thickness as a function of inlet drop size, flow rate, and the physical properties of the system.
Friction modification in a coupled system
Authors: Peters L. K. , Bender D. W. , Klinzing G. E. 
Published: June 2004

AbstractTwo‐phase solids‐in‐air flow was experimentally studied in a once through flexible wall tube flow system using nominal 25μm and 50μm spherical glass beads. For turbulent flow through the Silastic tube without a damping medium behind the wall, cases of true drag reduction and no drag reduction were found. The rate of addition of the glass beads was seen to be a correlatable parameter for both the flexible and rigid wall systems. A mechanistic model is proposed for interpretation of the results. It was qualitatively observed that the presence of an electrostatic charge on the particles at low relative humidities had a pronounced effect on increasing the drag in the system.
Pressure drop and holdup in stratified gas‐liquid flow
Authors: Russell T. W. F. , Etchells A. W. , Jensen R. H. , Arruda P. J. 
Published: June 2004

AbstractA mathematical model and an iterative procedure to calculate holdup and pressure drop in horizontal gas‐liquid flow is developed. The predictions of the model agree with well over a hundred data points collected with air‐water and air‐glycerine solutions in 0.0254‐, 0.0381‐, and 0.0508‐m. diameter pilot pipelines. A design procedure using the verified model is presented.
Gas absorption by non‐Newtonian fluids in agitated vessels
Authors: Perez Jerome F. , Sandall Orville C. 
Published: June 2004

AbstractCarbon dioxide was absorbed by aqueous Carbopol solutions in a turbine‐agitated vessel for the cases of absorption across an unbroken interface and absorption with the gas bubbling through the liquid. The rheological behavior of the solutions was described by the non‐Newtonian power law model with flow behavior indices varying from 0.92 to 0.59. An effective viscosity technique which had previously been developed to correlate agitated vessel rates of viscous dissipation and heat transfer with power law pseudoplastic fluids was used to correlate the data.
Effect of mass transfer on laminar jet breakup: Part I. Liquid jets in gases
Authors: Burkholder Harry C. , Berg John C. 
Published: June 2004

AbstractThe instability and breakup of laminar liquid jets in gaseous surroundings is investigated for conditions under which a solute is transferring across the jet interface rendering the system susceptible to Marangoni convection. Linear hydrodynamic stability analysis reveals that solute transfer out of the jet is stabilizing (produces longer jets) while transfer into the jet is destabilizing and promotes breakup. Solute adsorption, including as a limiting case the presence of a spread surfactant monolayer, may strongly counteract the stabilizing or destabilizing effects of mass transfer but has only a negligible effect on jet stability in the absence of interphase mass transfer. Qualitative experimental results for water jets in air with acetone as the transferring solute corroborate both the stabilizing and destabilizing mass transfer effects predicted by the theory.
Fixed bed desorption behavior of gases with nonlinear equilibria: Part II. Dilute, multicomponent, isothermal systems
Authors: Zwiebel Imre , Kralik Christopher M. , Schnitzer Jay J. 
Published: June 2004

AbstractGeneralized depletion curves for desorption (and Corresponding breakthrough curves for adsorption) were calculated for systems characterized by the Langmuir‐type multicomponent equilibrium equation and controlled by the film type rate model. In contrast with adsorption where the nonkey (or less strongly adsorbed) component curves display overshoots above feed concentration, in desorption the key component depletion curves exhibit the instabilities in the form of inflections and curvatures. As in the one component case, the differences in the depletion and breakthrough curves may be related to the rate phenomena. The undulations in the key component depletion curves may be characterized by derivatives of the rate data. The major significance of these instabilities is to elongate the depletion curves, which in turn requires the expenditure of added effort during regeneration. Process modifications are indicated, which could suppress the instabilities. The predicted trends were confirmed by experimental depletion curves.
Experimental investigation of polarization effects in reverse osmosis
Authors: Johnson A. R. 
Published: June 2004

AbstractWith a Mach‐Zehnder interferometer, salt concentration profiles were measured in a reverse osmosis system under natural convection with the membrane in a vertical position. The measured concentration profiles compared favorably with those predicted theoretically as long as the motion remained laminar. At large distances from the leading edge, however, the flow developed a wavy pattern, especially for bulk salt concentrations in excess of 0.1 moles/liter. As expected, whenever this motion became especially pronounced, the concentration of salt at the membrane surface was less and the production rate of fresh water greater than that predicted using the laminar analysis.
Co‐rotational rheological models and the Goddard expansion
Authors: Bird R. Byron , Hassager Ole , Abdel‐Khalik S. I. 
Published: June 2004

AbstractA survey is given of co‐rotational rheological equations suitable for describing the flow of viscoelastic liquids such as polymer solutions and melts. Comparisons are given with experimental data and molecular theories. An introduction to kinematical descriptions in co‐rotating reference frames is included.
Dynamic meniscus profiles in free coating III predictions based on two‐dimensional flow fields
Authors: Lee Chie Y. , Tallmadge John A. 
Published: June 2004

AbstractOne challenging problem in liquid‐gas, interfacial phenomena is the prediction of the size and location of a flowing meniscus because it involves surfaces which are highly curved. The paper presents one aspect of this problem. A numerical method is presented for predicting the dynamic meniscus profiles–specifically these distorted considerably by flow. The geometry considered to provide those free (liquid‐gas) surfaces is coating of a moving sheet by upward withdrawal from a finite bath. The predicted profiles agree with data taken with a glycerine‐water solution and with viscous oils.The method predicts the three parameters (coating thickness and two others) which are the minimum number of parameters necessary to describe the dynamic‐meniscus profiles for this geometry. The numerical method is iterative, it simultaneously predicts the flow field in the bath, and it is based on the two‐dimensional Navier‐Stokes equations and appropriate boundary conditions. The interfacial boundary condition used for iteration is the normal stress condition which is composed of pressure, surface tension, and viscous terms.
Developing and fully developed velocity profiles for inelastic power law fluids in an annulus
Authors: Tiu Carlos , Bhattacharyya Satinath 
Published: June 2004

AbstractDeveloping and fully developed velocity profiles with respect to position for laminar flow of inelastic fluids in an annulus were measured using streak photography. The polymer solutions used in the investigation were found to exhibit power law behavior under the present experimental conditions. The experimental results substantiated published theoretical solutions for developing and fully developed flow of power‐law fluids in annuli, and also indicated good agreement between the measured and predicted entrance lengths. The dimensionless entrance length was found to increase with increasing flow behavior index for the inelastic power‐law fluids.
Distribution coefficients at high dilution for organic solutes between water and isobutane or isobutylene
Authors: Won K. W. , Prausnitz J. M. 
Published: June 2004

AbstractTo facilitate design of an extraction process for removal of organic solutes from petroleum and petrochemical waste streams distribution‐coefficient date were obtained for typical organic pollutants at high dilution. Volatile solvents were chosen because of their low solubility in water and because they are recovered easily. Samples form both the aqueous and the organic phase were analyzed chromatographically. To remove a sample from an equilibrium cell operating at ressures well above atmospheric, a special technique was developed using low‐melting Indalloy for micro‐encapsulation.Distribution coefficients at ambient temperature are given for a variety of solutes, including esters, phenolics, ketones, and aldehydes. The results are correlated by a simple relation based on perturbed‐hard‐sphere theory for dilute solutions. Isobutane or isobutylene may be particularly useful in a dual‐solvent extraction process wherein a polar organic solvent is used in a secondary extraction tod remove the polar solvent from water.
Legendre transforms and their application in thermodynamics
Authors: Beegle Bruce L. , Modell Michael , Reid Robert C. 
Published: June 2004

AbstractLegendre transform theory is: (1) developed to show the relationships among the common thermodynamic potential functions (that is, energy, enthalpy, and free energy); (2) extended to introduce other potential functions which are particularly convenient in certain applications (for example, stability and critical point phenomena of multicomponent systems). General derivative operators are employed to allow partial derivatives of a given potential functions to be transformed to derivatives of other potential functions.
Thermodynamic stability criterion for pure substances and mixtures
Authors: Beegle Bruce L. , Modell Michael , Reid Robert C. 
Published: June 2004

AbstractCriteria are derived to specify the limit of stability for pure material and multicomponent thermodynamic systems. Through the use of Legendre transforms, the criteria may be expressed in a very simple form that only involves the determination of positiveness of a single second‐order partial derivative of a potential function. Alternate and equivalent criteria are shown to result from a simple reordering of the independent variables in the Fundamental Equation of Gibbs. Certain criteria that are often stated as necessary conditions of stability (for example, Cv > 0) are shown to be insufficient for specifying the limit of stability; that is, a system will always become unstable for other reasons before Cb can attain a negative value.
Estimation of bubble diameter in gaseous fluidized beds
Authors: Mori S. , Wen C. Y. 
Published: June 2004

AbstractBubble size is one of the most important parameters in the design and simulation of a fluidized‐bed reactor.A correlation of the bubble size and growth in fluidized beds of various diameters is developed. A maximum bubble diameter determined from the bubble coalescence is incorporated in the correlation to relate the effect of the bed diameter on the bubble size.Experimental data of bubble size reported are used to develop and test the validity of the correlation. The bubble diameters calculated using this correlation show good agreement with the observed bubble diameters.
Some fundamental aspects of spray drying
Authors: Katta S. , Gauvin W. H. 
Published: June 2004

AbstractEquations are proposed to predict the three‐dimensional motion of droplets in a spray dryer, based on a knowledge of the characteristics of the atomizing device and of the gas flow patterns in the drying chamber. If the droplet size distribution produced by the atomizing device is known or can be assumed, the trajectories of the droplets can be calculated throughout the drying process and hence the evaporative capacity and thermal efficiency of the spray dryer can be predicted.Experimental verification of this theoretical approach was obtained from a study of the drying of calcium lignosulfonate solutions of various concentrations in a 122‐cm diam. × 183‐cm high laboratory circular concurrent chamber with a conical bottom where the drying air was introduced tangentially near the top.An experimental study of the effects of a number of operating variables on the capacity and the efficiency of the spray dryer was also carried out. These effects were interpreted in terms of the droplet trajectories obtained in each case.
Mathematical modeling of atomizing scrubbers
Authors: Taheri Mansoor , Sheih Ching Ming 
Published: June 2004

AbstractA mathematical model for predicting particle collection efficiency in an atomizing scrubber has been developed. The model solves the diffusion equations for both droplets and particles by using particle in cell technique. The effect of scrubber size and water distribution from various points of injection have been studied on collection efficiency. The results of the mathematical prediction agrees very well with the data reported in the literature for a wide variety of operating conditions and configurations.