bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalized thermodynamic properties of real gases: Part II. Generalized Benedict‐Webb‐Rubin equation of state for real gases
Authors: Su Gouq‐Jen , Viswanath D. S. 
Published: June 2004

AbstractBy use of a least‐squares technique, a set of parameters for the generalized Benedict‐Webb‐Rubin equation is determined. The generalization of the equation is based on the modified theorem of corresponding states. The generalized equation shows a grand average absolute deviation of 1.6% in predicting the observed values of reduced pressure. The set of constants has been determined for densities up to twice the critical density in the reduced pressure range of 0 to 40.0 and a reduced temperature range of 1.0 to 15.0. The recommended generalized constants are Ao′ = 0.24180980, ao′ = 0.04407059 a′ α′ = 0.11369478 × 10−3, Bo′ = 0.07643101, b′ = 0.03715171, Co′ = 0.21217005, c′ = 0.06448001 and γ′ = 0.06.
Feedback control of an overdetermined storage system
Authors: Wilde Douglass J. 
Published: June 2004

AbstractAlthough it is already known how to apply feedforward control to an overdetermined system (2), feedback control is more difficult because overdeterminancy involves more measured variables than controllers. Feedback control is possible for a system of production units separated by storage tanks holding intermediate products and perturbed by random external upsets (1). Two types of feedback control are studied: local control in which each manipulated variable is controlled by the levels in the two tanks immediately adjacent, and central control in which all the levels simultaneously affect each manipulated variable. The behavior of these systems for three‐action linear controllers is described. Proportional local control is shown to have a structure similar to those of the unrefluxed countercurrent separation processes of the chemical industry. Such systems are therefore inherently stable. Central control, although requiring a more complicated equipment arrangement, actually has a simpler dynamic behavior because it cancels out interactions between controllers.
An experimental investigation of air bubble motion in a turbulent water stream
Authors: Baker James L. L. , Chao Bei T. 
Published: June 2004

AbstractThe motion of individual air bubbles in a water stream flowing turbulently in a 4 in. × 4 in. vertical conduit is investigated by photographic means. The bulk water velocity ranges from 40.8 to 267 cm./sec., corresponding to a system Reynolds number range of 48,600 to 386,000. Both tap and demineralized water were used at or near room temperatures. Air bubbles range from 0.038 to 0.70 cm. in equivalent radius and the corresponding bubble Reynolds number based on relative velocity ranges from 58 to 4,500.The results indicated that the bubble relative velocity in a turbulent water stream is similar to the rise velocity of single bubbles through a quiescent liquid. It was found to be practically independent of the system Reynolds number for bubbles having an equivalent radius above 0.3 cm. Large fluctuations in the bubble velocities were noted in all cases. The drag coefficient is, in general, lower for the demineralized water tests than for tap water when the bubble Reynolds number is below 2,000. Above this value, a mergence of the drag coefficients for all tests occur with a peak of approximately 2.0 at a bubble Reynolds number of 3,000, which is lower than the nonflow value of 2.6.
Excess transport properties of light molecules
Authors: Rogers John D. , Brickwedde F. G. 
Published: June 2004

AbstractA detailed study has been made of the excess viscosity of dense‐phase aragon, deuterium, helium‐3, helium‐4, para and normal hydrogen, neon, and nitrogen and of the excess thermal conductivity of normal hydrogen. A definite temperature dependence for the excess viscosity vs. density has been shown to exist for argon, helium‐4, hydrogen, and nitrogen and to be indicated for deuterium. The existing thermal conductivity data for hydrogen have been examined. A theoretical analysis for the qualitative behavior of excess thermal conductivity is given. The critical point viscosity values for all the species are given. Graphs, together with references to 1‐atm. data, are presented for computation of the transport properties.
Stability in distributed parameter systems
Authors: Amundson Neal R. , Raymond Lee R. 
Published: June 2004

AbstractThree models of a catalyst particle are examined for existence of multiple steady states depending upon whether intraparticle heat conduction or diffusion is important. The particle with constant temperature but with intraparticle diffusion is examined in detail and a necessary and sufficient condition for the stability of the steady state is obtained. Calculations are made for a particle with both intraparticle diffusion and conduction and it is shown that there may be multiple steady states some of which are unstable to small perturbations.
The mixed suspension, mixed product removal crystallizer as a concept in crystallizer design
Authors: Randolph Alan D. 
Published: June 2004

AbstractSimultaneous population and mass balances have been solved together with a generalized form of nucleation‐growth rate kinetics to obtain the form of crystal size distribution (CSD) for several idealized modes of crystallizer operation, including seed crystal removal, product classification, arbitrary solids concentration, and staged vessels. The effect of holding time and feed supersaturation on crystal size in a mixed suspension, mixed product removal (MSMPR) crystallizer was also studied. A representative CSD from an MSMPR crystallizer plus the relative kinetic order of nucleation to growth rate can be used to predict CSD from any of the above modes of operation.
The effect of concentration on diffusion coefficient in polymer solutions
Authors: Secor Robert M. 
Published: June 2004

AbstractA microinterferometric method was used to measure the diffusion coefficient as a function of concentration in the system dimethylformamide‐polyacrylonitrile at 25°C. The diffusion coefficient increases with increasing polymer concentration up to the maximum employed, 17.72% by weight. The theoretical basis for this type of behavior is explained. The diffusion coefficient in the limit as the polymer concentration approaches zero was calculated from theory to be 0.30 × 10−6 sq.cm./sec. This value is consistent with the diffusion coefficients obtained experimentally.
Calorimetric determination of the isothermal pressure effect on the enthalpy of the propane‐benzene system
Authors: Yarborough Lyman , Edmister Wayne C. 
Published: June 2004

AbstractAn isothermal throttling calorimeter system has been built for obtaining the effects of pressure on the enthalpy of liquids and vapors. The propane‐benzene system has been studied at 200°0, 300°, and 400°F. for pressures from 200 to 1,000 Ib./sq.in.abs.The experimental results are evaluated with respect to errors, and the data on the pure components are compared with values from the literature. Calculation methods are employed, and the calculated results are compared with the experimental data in an effort to evaluate the calculation methods.
Influence of catalyst particle size on reaction kinetics: Hydrogenation of ethylene on nickel
Authors: Fulton J. W. , Crosser O. K. 
Published: June 2004

AbstractThe influence of catalyst particle size upon the reaction rate was studied for the hydrogenation of ethylene with nickel‐on‐alumina in a packed‐bed flow reactor. A threefold increase in particle diameter through a critical size range (0.03‐ to 0.09‐cm. diameter, corresponding to a Reynolds number of around 1) produced a thirtyfold increase in reaction rate per unit external surface area. The behavior of the system indicates that this increase was due to the influence of external gas‐solid transport phenomena on the reaction kinetics. j‐Factor correlations were used to calculate the catalyst surface temperatures and concentrations, which were used to calculate Arrhenius activation energies and reaction rates from available rate expressions.
The viscosity of nonpolar gas mixtures at moderate and high pressures
Authors: Dean David E. , Stiel Leonard I. 
Published: June 2004

AbstractA method has been developed for the calculation of the viscosity of nonpolar gas mixtures at moderate and elevated pressures from the molecular weights and critical constants of the components. By the use of available experimental data and appropriate pseudocritical constant rules, results obtained previously for the viscosity of pure gases have been extended to mixtures. Viscosity values calculated by the method developed in this study for a number of nonpolar gas mixtures were found to reproduce reported values with a high degree of accuracy.
Unsteady state mass transfer from gas bubbles—liquid phase resistance
Authors: Li Pang‐Sheng , West Frank B. , Vance William H. , Moulton Ralph W. 
Published: June 2004

AbstractLiquid phase mass transfer coefficients were determined for streams of bubbles of pure oxygen, 10% carbon dioxide in air, and 10% chlorine in air all rising in water. The results were compared with coefficients predicted by Higbie's equation for unsteady state diffusion into transient films. The observed coefficients for oxygen and carbon dioxide were slightly higher than predicted. The experimental absorption coefficients based on the free chlorine concentrations were in good agreement with the predictions assuming simultaneous irreversible reaction with the transient water film and a pseudo first‐order reaction rate constant of 13.7 sec.−1.
Interstage mixing in an Oldshue‐Rushton liquid‐liquid extraction column
Authors: Gutoff Edger B. 
Published: June 2004

AbstractInterstage mixing was measured in a 4‐in. Oldshue‐Rushton column fed with a salt solution at the top and distilled water at the diluted salt solution leaving at the top.Mixing between stages is relatively slight at low agitator speeds, but increases very rapidly with speed once the turbulent region is reached. Interstage mixing is reported in terms of bulk backflows and also in terms of eddy diffusivities. The amount of interstage mixing is similar to that reported in the literature for rotating disc contactors.Variations in the horizontal baffle plate design were also studied.
Studies of boiling heat transfer with electrical fields: Part I. Effect of applied A. C. voltage on boiling heat transfer to water in forced circulation
Authors: Markels Michael , Durfee Robert L. 
Published: June 2004

AbstractAlternating current voltage (60 cycles/sec.) was found to increase boiling heat transfer rates and prevent film boiling for deionized water under forced convection at essentially ambient pressure. Steam was used to supply heat to the interior wall of a 0.292‐in. thick annulus, and voltages up to 5,000 v. were impressed across the region of vapor formation. The highest heat transfer rates reached were approximately twice the normal nucleate boiling peak. The application of voltage increased the boiling heat transfer over the entire range tested—mass flow rates up to 5.2 × 105 lb./hr.‐sq.ft. and exit qualities up to 4% by weight vapor. Data obtained from tests in which the external wall of the flow annulus was heated indicated an increase in heat flux up to 2,000 v., followed by a decrease in heat flux at voltages above 2,000 v.
Model simulation of stirred tank reactors
Authors: Manning F. S. , Wolf David , Keairns D. L. 
Published: June 2004

AbstractStirred tank reactor yields are successfully described by the following model. The impeller is considered to act as a local micro‐mixer that perfectly mixes the recirculating stream down to the molecular level. All other portions of the vessel act as a large volume macro‐mixer, throughout which the impeller discharge stream remains completely segregated. Changes in overall conversion due to variations in mean residence time, impeller size, and rev./min. as predicted by this micro‐ and macro‐mixer model agree with Worrell's data for a relatively slow, second‐order, irreversible reaction.
Gas absorption in a fin‐wall conduit
Authors: Sweeney Thomas L. , Calvert Seymour 
Published: June 2004

AbstractGas absorption and pressure drop were studied in a fin‐wall conduit; a fin‐wall conduit is a rectangular duct with fins placed on two internal walls perpendicular to the axis of flow. Pressure drop data were obtained with the air‐water system. Gas absorption data were obtained with the air‐ammonia‐water system, and were corrected for the expected liquid‐phase resistance by the use of oxygen desorption data. The pressure drop per transfer unit is on the order of 0.05 in. of water per transfer unit.
The condensation of mixed vapors
Authors: Estrin Joseph , Hayes T. W. , Drew T. B. 
Published: June 2004

AbstractAlthough condensation from saturated mixed vapors upon a cold surface has been frequently explored experimentally, current theories describing this phenomenon have not been adequately tested. This work describes the condensation process in which two condensable components are involved and how, consequently, the mass transfer process is involved in their partial fractionation.A discussion of the Bedingfield correction (3) for the effect of molecular weight difference of the diffusing components upon the mass transfer coefficient leads to its necessary association with the Ackermann factor (4, 5) for the general mass transfer effect. Data from two sets of experiments using different apparatuses demonstrate the use of this net corrective factor and also demonstrate the general applicability of the Drew‐Colburn mass transfer coefficient, for transfer processes in which more than one component transfers from one phase to another.
Heat transfer in a fuel cell battery
Authors: Gidaspow Dimitri , Baker Bernard S. 
Published: June 2004

AbstractAnalytical solutions were obtained for temperature distributions in a single adiabatic fuel cell with heat generation by TΔS, I2R, and polarization. With these results it is possible to characterize heat transfer in a battery with convection in the fuel and air streams, and with conduction of heat in three directions, by means of an average temperature for which an analytical solution was also obtained. Although the temperature can be kept within safe limits in low‐power density batteries, the results show that critical dimensions exist beyond which failure by thermal buckling will occur.
Performance of a packed distillation column with electrically heated packing
Authors: Somer Tarik G. 
Published: June 2004

AbstractElectric current was applied across the coke packing of a glass column, distilling carbon tetrachloride‐benzene at total reflux. Heat generated by electricity boiled the liquid on the packing surface. Bubbles rising across the liquid film reduced its resistance to mass transfer, improving the column efficiencyTheoretical analysis and experimental results are presented.
Effects of mixing on chain reactions in isothermal photoreactors
Authors: Hill Frank B. , Felder Richard M. 
Published: June 2004

AbstractAn analytical study of the interaction of mixing, radiation attenuation, and chemical kinetics in isothermal photoreactors is presented. For a particular chain reaction mechanism in the presence of stationary state kinetics and low conversion, the conditions required for the existence of mixing effects are formally stated, and the direction of change of conversion and quantum yield resulting from the introduction of mixing is established. Calculated results are presented for monoenergetic, unidirectional sources. Factors considered include mode of chain termination, radiation attenuation law, photoreactor geometry, state of mixing, and reactor optical thickness. Chemical and mixing time scale considerations are discussed.
An application of adaptive control to a continuous stirred tank reactor
Authors: Crandall Edward D. , Stevens William F. 
Published: June 2004

AbstractThis paper reports on an investigation of the effect of adaptive control on a closed‐loop chemical plant. The plant controlled was a simple closed‐loop feedback system, the elements of which were a proportional controller and an elementary continuous stirred‐tank reactor. The reaction involved was an exothermic, single‐reactant decomposition, with the control criterion being the integral of the square of the deviation of the output composition from a value determined by a reference model. The adaptive control system incorporated an automatic identification scheme and a decision process, and operated in the presence of disturbances in cooling water temperature and/or catalyst activity.The adaptive control system yielded excellent results. For all disturbances, the output of the adaptive controlled plant remained much closer to the reference model output than did the output of the simply controlled plant. Inclusion of an adaptive capability in a control system thus appears to be desirable and often feasible.
Experimental studies of three‐dimensional filtration on a circular leaf
Authors: Leonard J. I. , Brenner Howard 
Published: June 2004

AbstractA previous study (3) revealed a discrepancy between the actual shape of a spheroidal filter cake formed on a laterally unconfined circular test leaf, and that predicted from theory. This discrepancy was tentatively attributed to either cake compressibility or filter cloth resistance that was neglected in the mathematical model and not controlled in the original experiments. More extensive and systematic experiments reported in the present paper, employing incompressible cakes and filter media of negligible resistance, display similar behavior. (Cake incompressibility and negligible septum resistance were quantitatively established by conventional one‐dimensional experiments.) It is speculated that the observed departure from theory may be due to the inapplicability of Darcy's law, especially in the early stages of cake formation.
On finite amplitude roll cell disturbances in a fluid layer subjected to heat and mass transfer
Authors: Sani R. L. 
Published: June 2004

AbstractThe system consists of a thin, transversely infinite horizontal fluid layer initially in mechanical but not thermostatic or speciestatic equilibrium. The top and bottom surfaces of the layer are assumed to be unconstrained, and the stability of the system to buoyancy driven finite amplitude roll cell disturbances is investigated. The system is capable of exhibiting both a subcritical stationary and oscillatory instability. The average vertical transport of heat and mass is computed and it is found that the convective transport associated with a stationary type of instability is much greater then that corresponding to an oscillatory instability.
Dimensional analysis in photochemical reactor design
Authors: Dolan William J. , Dimon Carl A. , Dranoff Joshua S. 
Published: June 2004

AbstractThe equations which describe the performance of a continuous tubular photochemical reator have been formulated and analyzed by dimensional analysis. Experimental data obtained in a study of the decomposition of hexachloroplatinic acid in water were correlated as suggested by the dimensional analysis, thus partially confirming the validity of the approach.
Diffusion through the liquid‐liquid interface: Part II. Interfacial resistance in three‐component systems
Authors: Ward W. J. , Quinn J. A. 
Published: June 2004

AbstractIn an investigation of the transfer of solute molecules across the liquid‐liquid interface, the transfer of acetic acid, benzoic acid, oleic acid, and cholesterol between benzene and water was measured. Experiments were carried out with a laminar jet apparatus wherein the organic phase was spread as a thin film on the surface of an aqueous jet. The results indicate that any interfacial resistance in these systems is negligibly small.
Stresses in a viscoelastic fluid in coverging and diverging flow
Authors: Adams E. B. , Whitehead J. C. , Bogue D. C. 
Published: June 2004

AbstractBirefringent studies have been carried out on a viscoelastic fluid (polystyrene in Aroclor) flowing in straight, converging, and diverging channels, for the purpose of obtaining point‐by‐point stress data (the shear stress and the difference in normal stresses). A preliminary analysis in terms of the Coleman‐Noll second order theory for viscoelastic fluids shows good agreement.
Multicomponent vapor‐liquid equilibria at high pressures: Part I. Experimental study of the nitrogen—oxygen—carbon dioxide system at 0°C
Authors: Muirbrook N. K. , Prausnitz J. M. 
Published: June 2004

AbstractA description is given of a dynamic vapor‐liquid equilibrium apparatus in which both phases are recirculated by vane pumps especially designed for high‐pressure service. Equilibrium phase compositions as well as vapor and liquid molar volumes up to the critical pressure are reported for the two binary systems nitrogen‐carbon dioxide and oxygen‐carbon dioxide and for the ternary.
The determination of eddy mass diffusivities for the air‐water system in a wetted‐wall column
Authors: Bunch David W. , Strunk Mailand R. 
Published: June 2004

AbstractEddy mass diffusivities as a function of radial position for different Reynolds numbers have been determined for air flowing countercurrently to water in a wetted‐wall column. The ratios of the eddy mass diffusivity to the eddy viscosity also were determined. The wetted‐wall column was constructed from Pyrex glass with an I.D. of 2.75 in. and a wetted section 39 in. in length. An approach section was constructed from the same material and of adequate length to insure full development of the velocity profile. The gas phase Reynolds numbers varied from 3,200 to 54,300. The liquid phase flow was laminar. The concentration and velocity profiles of the air stream were measured experimentally and bulk temperatures of all streams were obtained. A probe was developed to measure the concentration profiles. The probe consisted of platinum wires wrapped in a helix around a glass capillary tube on which a thin layer of lithium chloride in polyvinyl alcohol had been deposited. The resistance of the probe was a reliable indication of the water vapor concentration in the air stream. The probe was calibrated and used for all concentration measurements. Eddy mass diffusivities were evaluated from a solution of the steady state mass diffusion equation by means of a digital computer with experimental velocity and concentration profiles. Qualitatively, the eddy diffusivity profiles are similar to those which have been obtained for heat and momentum transfer. When these profiles are used with the diffusion expression, they are capable of accurate evaluation of the concentration profile. The ratio of the eddy mass diffusivity to the eddy viscosity was determined and was found to be less than 1.0 over most of the cross section, but the ratio increased to values greater than 1.0 near the center and near the walls of the column.