bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mathematical modeling of a modified scheibel liquid‐liquid extraction column in the frequency domain
Authors: Pang K. H. , Johnson A. I. 
Published: March 2009

AbstractThe frequency response of a modified Scheibel liquid‐liquid extraction column was experimentally determined from pulse testing data obtained by Pollock. Mathematical modeling was carried out in the frequency domain. Several non‐identical, non equilibrium, perfect mixing stage models were used to describe the dynamic behavior of the column. A signal flowgraph technique was found to be suitable for determining the theoretical frequency response of the non‐identical stage models. All models proposed in this study appeared to simulate satisfactorily the behavior of both the extract and raffinate phases. The theoretical frequency and transient responses agreed very well with experimental data
Heat and mass transfer during air drying of solids
Authors: Bimbenet J. J. , Loncin M. , Brusset H. 
Published: March 2009

AbstractHeat and mass transfer are studied for drying of a semi‐infinite solid in warm air. The mathematical model, a system of partial differential equations, gives an exact analytical solution if transfer coefficients are constant and free water present at the surface. An analogy has been found for heat transfer with and without drying. A finite‐difference solution of broader application than the analytical method has been developed, and the two methods agree closely. Experiments are described which show fair agreement with calculations of heat transfer during the first step of drying. Water content profiles remain flat during that period and no precise comparison can be made
Prediction of heats of mixing of liquid mixtures containing aliphatic hydrocarbons and ketones by a group solution model
Authors: Nguyen T. H. , Ratcliff G. A. 
Published: March 2009

AbstractA group solution model for heats of mixing of liquid mixtures has been tested and found satisfactory for mixtures containing ketones and alkanes. No provision was made for a skeletal contributionGroup contribution functions were generated from experimental data on acetone/n‐hexane mixtures at 25°C and are presented. These functions allow the prediction of heats of mixing of binary or multicomponent mixtures containing alkanes and/or ketones at 25°C. No experimental data are required
The dispersion of material in slowly moving fluids
Authors: King R. P. , Woodburn E. T. , Riele W. A. M. Te 
Published: March 2009

AbstractThe dispersing action of a mass of slowly moving fluid is modelled by a stochastic partial differential equation. The separate components of the fluid velocity are represented as stochastic processes and appear as coefficients in that equation. These processes can take one of two forms: Markov processes with finite state‐space, or independent Ornstein‐Uhlenbeck processes.To confirm the predictions of the model they were compared with the mean response to a pulse‐like injection of tracer and with the observed cross‐correlation between tracer concentration at two points in the fluid. The statistical properties of the velocity processes, as estimated from these tracer studies, were confirmed by direct measurement with a hot‐film anemometer probe.
The effect of non‐uniform porosity in causing flow maldistributions in isothermal packed beds
Authors: Stanek V. , Szekely J. 
Published: March 2009

AbstractA formulation is developed for the flow of an incompressible fluid through a two dimensional packed bed having a spatially variable void fraction, through the statement of the Ergun Equation in a two dimensional system.Computed results are presented for particular spatially distributed void fractions in the bed, which indicate that a lateral variation in the resistance to flow may cause appreciable flow maldistribution and “cross flow” effects.This work is thought to be a first, necessary step in the quantitative understanding of channeling and by‐pass phenomena in packed bed reactors.
The grinding of organic dyestuffs
Authors: Jenczewski Theodore J. 
Published: March 2009

AbstractA mechanism for grinding disperse dyes in a sand mill is discussed which is supported by experimental data. Experimental data with disk, cylinder and vibrator agitators are examined from the point of view of dimensional analysis. All rotors exhibited fluid slip and decreased efficiencies at high rotor speeds. Cylinder rotors provided higher rates of energy input to the milling paste, and shorter grinding times, relative to disk and vibrator agitators.
Prediction of enthalpy of saturated paraffin binary hydrocarbon mixtures
Authors: Ghormley E. L. , Lenoir J. M. 
Published: March 2009

AbstractA method of predicting the thermal phase boundary of aliphatic hydrocarbons is presented. Equations describe the saturated enthalpy boundary of pure substances and binary mixtures of hydrocarbons up to the critical temperature. A method of predicting the cricondentherm has been developed to establish the upper limit of the enthalpy envelope for binary mixed aliphatic hydrocarbons. Calculated enthalpies have an average deviation of 0.5% for pure hydrocarbons and 0.8% for mixed hydrocarbons.
The excess enthalpy of gaseous mixtures of carbon dioxide with methane
Authors: Lee J. I. , Mather A. E. 
Published: March 2009

AbstractExcess enthalpies (heats of mixing) of mixtures of methane and carbon dioxide have been measured in a flow calorimeter at temperatures between 10°C and 80°C and pressures up to 100 atmospheres. All measurements were for the mixing of two gas phases. The results were compared with various predictions based on equations of state and the principle of corresponding states.
On the merits of partial fluid mixing in the biochemical reactor system
Authors: Chen Gilbert K. C. , Fan L. T. , Erickson L. E. 
Published: March 2009

AbstractFor autocatalytic reactions such as those associated with many biochemical processes, the rate of a reaction is influenced by the concentrations of some of the products as well as those of the reactants. By use of the so‐called diffusion (axial dispersion) model in conjunction with the Monod growth kinetics, it is shown that partial (incomplete) fluid mixing is often desirable for this class of reactions. Under sterile feed conditions, the optimal Peclet number appears to range between 0 and 2 with the exact value depending on the values of the kinetic constants and initial substrate concentration. By varying this single parameter, the performances of such reactors under various degrees of fluid mixing can be readily investigated using the axial dispersion model. The optimal design may be physically realized by the use of a tower fermentor with controlled axial dispersion.
Activation analysis of environmental pollutants
Authors: Chattopadhyay A. , Bennett L. G. I. , Jervis R. E. 
Published: March 2009

AbstractActivation analysis is a highly sensitive and specific technique for the detection of trace heavy metal pollutants in environmental materials. Comparison of natural “baseline” levels with elevated levels provides direct evidence of contamination. Neutron activation analysis (NAA) is used in this study to determine arsenic, zinc, cadmium, and mercury. Photo‐nuclear activation analysis (PNAA) is used to determine lead in soils. Holland Marsh, a market‐gardening area north of Toronto, has been studied as various herbicides and fungicides have been used there. The analyses of soil and vegetation samples, and of human head hair collected from residents are reported.
Radial mixing and residence times in the liquid phase in gas‐liquid annular flow in vertical tubes
Authors: Jagota A. K. , Scott D. S. , Rhodes E. 
Published: March 2009

AbstractTheory for calculating the mean velocities of the drops and of the film in gas‐liquid cocurrent annular flow by use of tracer pulse techniques has been developed. It is shown that the interaction between the film and the drops affects the mean residence times in each, and is much greater in its effect than is axial dispersion in the film or in the core.The theory also describes a relatively simple means of determining the mean amounts of droplet entrainment and liquid interchange between droplets and film from measurements made with continuous tracer injection. Knowledge of the entrainment and the mean velocities of film and drops is essential in determining the extent of interaction between the liquid film and the entrained liquid flow.
Flow visualization studies of a turbulent drag reducing solution
Authors: Arunachalam V.R. , Hummel R. L. , Smith J. W. 
Published: March 2009

AbstractA nondisturbing photochromic dye trace technique has been employed to study the flow profiles of water‐alcohol solutions containing the drag reducing polymer Polyox at concentrations of 0.55 to 5.5 ppm. Drag reductions of from 33 to 75% were observed in a smooth glass pipe. The dye traces show a thicker wall layer for the drag reducing solutions than that for the solvent alone. The core region is relatively unaffected by the polymer at 0.55 ppm and at 5.5 ppm the relative thickness of the turbulent core region has been greatly reduced. Earlier, unpublished work of Corinthios shows effectively no core at 33 ppm. Mean velocity and apparent axial turbulence intensity profiles obtained are in general agreement with previous data in the literature obtained with other methods and in the wall region the low frequency intensity is greater than that of the pure solvent. This is consistent with the results of Spangler but not those of Seyer. Higher low frequency intensities measured in the wall region suggest that higher frequency fluctuations are suppressed and/or that the time stability of eddies is increased as indicated by the reduced frequency of wall ejections in drag reducing solutions.
The solubility of hydrogen in aliphatic amines
Authors: Moore R. G. , Otto F. D. 
Published: March 2009

AbstractThe solubility of hydrogen in ammonia, monomethylamine, monoethylamine and n‐propylamine was determined at temperatures from −70°C to 25°C and in 1,2‐propanediamine and 1,2‐ethanediamine over the temperature ranges −25°C to 11°C and 25°C to 34°C respectively. Measurements were made at total pressures up to 300 psig. The solubility data were correlated in terms of Henry's law and the solubilities are in the range 1 × 10−5 to 3 × 10−4 mole fraction at a hydrogen partial pressure of 1 atmosphere. The measured solubility data were used to extend a correlation proposed by Yen and McKetta. This revised correlation may be used to estimate the solubility of hydrogen in polar, associated amines.
Experimental evaluation of feedback, feedforward and combined feedforward‐feedback binary distillation column control
Authors: Wood R. K. , Pacey W. C. 
Published: March 2009

AbstractThe control behavior of a nine inch diameter eight tray bubble cap column separating a methanol‐water mixture has been studied using feedback, feedforward and combined feedforward‐feedback control. Top product composition was controlled by manipulation of the reflux rate to compensate for feed flow disturbances. Pulse testing was used to determine the process transfer functions. Gain, gain plus time delay and gain plus time lag feedforward control were implemented by means of an IBM 1800 digital computer. Combined feedforward‐feedback control, using gain and gain plus time lag feedforward control action, was also studied. The improved column control behavior is compared with results obtained using only feedback control.
Some problems concerning the non‐adiabatic tubular reactor a‐priori bounds, qualitative behavior, preliminary uniqueness and stability considerations
Authors: Varma Arvind , Amundson Neal R. 
Published: March 2009

AbstractAn investigation of the non‐adiabatic tubular reactor, in which a single chemical reaction occurs, is presented. The steady state mass and heat balance equations are shown to be a pair of coupled, nonlinear differential equations, and are shown to uncouple into a single functional‐differential equation for the case Le = 1. A‐priori bounds on the steady state concentration and temperature are developed, and some remarks about the shape of the steady state profiles made. Sufficient conditions ensuring uniqueness of steady states and their asymptotic stability are derived.
Some statistical properties of turbulent momentum transfer in rough pipes
Authors: Dunn S. G. , Smith J. W. 
Published: March 2009

AbstractA non‐disturbing technique has been used to measure turbulence parameters in a smooth pipe and in two randomly roughened pipes at the same apparent wall shear.Near the wall, large eddies are significantly more intense in smooth than in rough pipes while the small eddies are more intense in rough than in smooth pipes. No viscous sublayer was visible in the rough pipes. In the core, large apparent differences in large scale eddy structure were found between rough and smooth tubes, but the differences probably result from the inappropiate inclusion of dissipation due to form drag in u*.
The hydrogenolysis of n‐Butane on a nickel on silica catalyst: II Fluidized bed studies
Authors: Orlickas A. , Hoffman T. W. , Shaw I. D. , Reilly P. M. 
Published: March 2009

AbstractThis study was undertaken to obtain experience in developing steady‐state mathematical models of full‐scale chemical reactors through the use of a combination of bench‐scale experiments and actual plant operating data. In this case, the hydrogenolysis of n‐butane on a nickel on silica gel catalyst was studied in a %inch diameter pilot plant fluidized bed reactor. The kinetic parameters in a mechanistic reaction model were obtained in a bench‐scale integral reactor and these rate equations were included in a simple two‐phase fluidized bed model. The parameter relating to interchange of gas between bubbles and emulsion was determined from the fluidized bed data. A comparison of the predicted and observed selectivities suggested a weakness in the kinetic model. This shortcoming was then partially corrected by using the fluidized bed data. In this way, a reactor model was achieved which was satisfactory for overall plant simulations.
Mathematical model and optimization of drying process for a through‐circulation dryer
Authors: Chung Seng F. 
Published: March 2009

AbstractA mathematical model of a through‐circulation dryer is proposed. This model approximates the drying time of constantrate drying and fallingrate drying processes. Based on the proposed model, the optimal drying conditions of maximizing the drying production rate in a continuous through‐circulation dryer are obtained. The drying production rate, in terms of the independent operating variables, is a nonlinear objective function, and is optimized under the nonlinear inequality constraint functions by a differential algorithm.
An improved algorithm for solving the mass balance equations in multistage separation processes
Authors: Boston J. F. , Sullivan S. L. 
Published: March 2009

AbstractThe reliability and efficiency of any method of solving the equations that describe multicomponent, multistage, counter‐current separation processes depend on the accuracy and efficiency of the algorithm that is employed to solve the component mass conservation (CMC) equations. Previous investigators have shown that ordinary Gaussian elimination is very efficient for solving the CMC equations when they are expressed in tridiagonal form. The present work, however, demonstrates that this procedure is subject to excessive round‐off error under certain conditions. In such cases, the error can be reduced to insignificant levels by using a newly developed algorithm based on recursion formulas derived specifically to treat the tridiagonal system of CMC equations.
Experimental heat capacities of nitrogen‐carbon dioxide mixtures at elevated pressures
Authors: Bishnoi P. R. , Hamaliuk G. P. , Robinson D. B. 
Published: March 2009

AbstractThe heat exchanger method of determining the ratio of heat capacity at a pressure to the heat capacity at a low pressure was used to obtain data on two binary mixtures of nitrogen and carbon dioxide containing 6.77 and 31.70 mole percent nitrogen. The data were obtained at pressures up to 2150 psia in the temperature range from ambient to 90°C. The results are believed to be accurate within ± 0.5% in the regions removed from the pressure maxima and within ± 1% in regions close to the maxima. Heat capacities of the two binary mixtures calculated using the BWR equation of state and new mixing rules compared favourably with the experimental data.
Testing consistency of vapor‐liquid equilibrium data in P‐T‐X space
Authors: Brinkman Norman D. , Weber James H. , Tao Luh C. 
Published: March 2009

AbstractA systematic method of calculating and presenting the results of consistency tests is given and illustrated on the methane‐ethane system in the space of −140 to 60°F and 100 to 700 psia. The results indicate incompatibility of error levels between isobars and isotherms. Also, different arrangements of terms in the thermodynamic differential equations were sometimes found to produce different levels of inconsistency for the same space. Results are analyzed and discussed.
Velocity measurements in turbulent flow of viscoelastic solutions
Authors: Rollin A. , Seyer F. A. 
Published: March 2009

AbstractAn experimental study, based on streak photograph determination of instantaneous velocities, was directed at determining the turbulent flow velocity profiles of polymer solutions in circular pipes. The measurements resolve several discrepancies in interpretation of earlier velocity profile measurements in drag reducing systems. In particular, it is shown for dilute drag reducers that the semilogarithmic profile due to Prandtl with the same slope as for Newtonian fluids is quantitatively correct provided Bogueés empirical correction function is applied to the data. For a relatively concentrated solution, data serve to extent on earlier study which has shown the flow to be transitional at surprisingly high values of Reynolds number.
Studies of ethylene chlorohydrin formation in a bubble column reactor
Authors: Saeki G. , Weng P. K. J. , Johnson A. I. 
Published: March 2009

AbstractAn experimental study of the reactions of ethylene, chlorine, and water in a bubble column reactor, on a laboratory scale, has been carried out. The effect of gas flow rates on the yield of the products in an unbaffled reactor is reported. Baffles were introduced into the column to reduce axial mixing. A significant improvement in the conversion and yield of ethylene to ethylene chlorohydrin was observed.
Fonction de transfert déun réservoir agité en système continu: I. Détermination à léaide déun traceur fluorescent
Authors: Pineault Gilles , Cloutier Leonce 
Published: March 2009

AbstractA fluorescent material which does not disturb the physical properties of the contacting fluids while allowing a continuous analysis of the concentration, has been used to study the mixing of two miscible liquids in a continuous stirred tank reactor (CSTR). The experimental results for three types of forcing functions, analysed by the frequency response method and Bode diagrams, show that a general first order transfer function describes the behavior of a CSTR when there is no density difference between fluids.
Sorption in davison 5 a molecular sieves
Authors: Ruthven D. M. , Derrah R. I. 
Published: March 2009

AbstractKinetic and equilibrium data are reported for the sorption of propane, propylene and 1‐butene in two commercial 5A molecular sieves (Davison C‐521 and C‐626). It is shown the kinetics of sorption are controlled by the diffusional resistance of the macropores and tortuosity factors are calculated from the experimental data. Rates of sorption are compared with previous data for the Linde 5A sieve. For measurements over large step changes in concentration, adsorption is much faster than desorption but these differences can be quantitatively accounted for by considering the non‐linearity of the equilibrium isotherms.
Foam fractionation of solutions containing two surfactants in stripping and reflux columns
Authors: Rubin Eliezer , Melech Doron 
Published: March 2009

AbstractAn experimental and theoretical investigation was undertaken in order to examine the effect of concentration, foam flow rate and feed flow rate on the separation of sodium dodecylbenzene sulfonate and sodium lauryl sulphate from solutions containing the two surfactants, in stripping and reflux columns. The experimental results indicated the conditions under which a stripping foam fractionation column behaves according to the model of an infinite column. Within the present experimental range reflux columns behaved always according to the model of an infinite column. Using this model it is possible to predict relative separation of surfactants in stripping and reflux columns from experimental data obtained in simple columns. Experiments with modified total reflux columns indicate great potential for batch foam fractionation.
The effect of concentration on the rates of dissolution of gibbsite and boehmite
Authors: Scotford R. F. , Glastonbury J. R. 
Published: March 2009

AbstractThe effect of caustic soda concentration on the rate of dissolution of gibbsite and boehmite was studied. The activity of sodium hydroxide rather than cencentration was found to be the best parameter for kinetically describing the effect of concentration on dissolution rate.For the gibbsite reaction, a first order dependence on sodium hydroxide activity was observed whilst the boehmite dissolution exhibited a dependence on the term (aNaOH. aH2O) which was first order above 210 g/1 Na2O and half order below that concentration.
Vortex nozzles for limitation of discharge rates
Authors: Boadway J. D. 
Published: March 2009

AbstractThe vortex nozzle, employing the radial pressure differential across a vortex can be effective in limiting the discharge of fluid or slurries from pressurized systems without using small throttling orifices which could plug readily.This paper deals with an investigation of vortex discharge devices which use this principle: It features measurements of velocities using a photographic trace technique. The measured radial distribution of mean tangential velocity departed from a free vortex pattern due to friction losses at the walls of the equipment. Empirical equations were developed for the tangential velocity and the flow, the coefficients being related to parameters of the design.
Migration of dispersed phases in a pulsed liquid in a pipe with asymmetric baffles
Authors: Chan K. W. , Baird M. H. I. 
Published: March 2009

AbstractDispersed particles tend to migrate in a preferred direction in a pulsed liquid flow in the presence of fixed baffles of asymmetric design. Conical and inclined disc baffles were found to promote migration of dense materials (sand, hematite) up an inclined length of 5.08 cm. diameter pipe. Conical baffles were effective in increasing the gas holdup in a vertically pulsed bubble column, provided the thick end of the cone was uppermost. These effects are thought to be due to the entrainment of the dispersed phase into separation vortices. Energy dissipation measurements with conical baffles are consistent with this model.
Prediction of vapor‐liquid equilibria by means of a modified clausius equation of state
Authors: Elshayal I. M. , Lu B. C.‐Y. 
Published: March 2009

AbstractThe Clausius equation was modified for the calculation of vapor‐liquid equilibria in binary and multicomponent systems. In the modification, the three parameters of the equation were considered temperature dependent. Molal volumes of saturated liquid and vapor together with the condition that the fugacities of the vapor and the liquid phase are equal at the condition of equilibrium were used for evaluating the parameters of pure components. Applications were made successfully to systems nitrogen‐methane, nitrogen‐oxygen, argon‐oxygen, nitrogen‐argon, argon‐methane, carbon dioxide‐hydrogen sulfide, carbon‐dioxide‐propane, hydrogen sulfide‐n‐butane and nitrogen‐argon‐oxygen.