bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of extruder variables on the gelatinisation of corn starch
Authors: Lawton B. T. , Henderson G. A. , Derlatka E. J. 
Published: March 2009

AbstractThe first stage of a study of the extrusion of starch‐based materials is described. The chemical and physical changes which occur in the extrusion of a corn starch‐water system relative to fifteen extruder variables have been investigated.A mathematical model of the extruder has been obtained from analysis of the data. The important variables were found to be moisture, barrel and die temperatures, screw speed and screw geometry. A strong interaction between moisture and barrel temperature was found to occur. These variables in the model account for 90.5% of the variance in the data obtained. The effects of the variables on the gelatinisation and shearing mechanical degradation of starch are discussed.
The use of carbon mass balances in the study of biological oxidation
Authors: Lamb A. , Tollefson E. L. 
Published: March 2009

AbstractCarbon mass balance techniques are applied to biological oxidation systems. Equations are developed for rates of substrate utilization and carbon dioxide production. Carbon balances for suspended cellular material are given. The total organic carbon analyzer was used for carbon balance determinations and illustrative examples taken from studies of biological oxidation toxicity to cupric ion. Problems with the use of the analyzer are discussed. Within the pH range 6–9, no effect of pH on organic carbon analysis was observed. Efficiency of substrate utilization and concentration of suspended solids in an activated sludge plant are both determined from carbon analyses. Suspended solids were also determined by a direct weighing procedure.
The influence of simple phenols on water aeration kinetics
Authors: Ganczarczyk J. 
Published: March 2009

AbstractSolutions of 20, 50, 100 and 150 mg/l of phenol and o‐cresol, and of 10, 20 and 50 mg/l of p‐xylenol were aerated in laboratory tank with the intensity in the range from 6 to 30 m3 of air per m3 per hr. The presence of phenol and o‐cresol in water enhanced the aeration kinetics with effects growing with aeration intensity. The presence of p‐xylenol caused increases or decreases in oxygen transfer rates, depending on the concentration of the substance and intensity of aeration. Only influence of phenol seemed not to be concentration dependent.
Diffusion behavior of univalent cations during cation interchange across an ion‐exchange membrane
Authors: Tombalakian A. S. 
Published: March 2009

AbstractMeasurements have been made of two‐cationic cell potentials and cation interchange fluxes for the exchange between K+, Na+, Li+ and H+ across a polystyrenesulfonic acid ion‐exchange membrane separating solutions of hydrochloric acid and the univalent chloride salts of varied composition. The experimental data have been used to estimate the magnitudes of ionic mobility ratios, membrane ionic concentrations, “effective” single‐ion diffusion and interdiffusion coefficients of the interchanging cations in the membrane corresponding to various time intervals during a normal integral cation interchange process. The results indicate that during cation interchange the “effective” single‐ion diffusion coefficients of the counterdiffusing cations in the membrane vary markedly over ranges of up to 80% of equilibrium of the interchange processes investigated.
Viscosity properties of suspensions at the limiting conditions for turbulent drag reduction
Authors: Kerekes R. J. E. , Douglas W. J. M. 
Published: March 2009

AbstractOn the basis of a postulated mechanism of drag reduction, the overall viscosity properties of suspensions are used to establish general quantitative criteria for the upper and lower limit on the conditions at which turbulent drag reduction can occur in suspensions of rigid, elongated, nearly neutrally‐buoyant particles.Experimental data obtained in drag reducing suspensions of nylon fibres in water verified, quantitatively, the criterion for the upper limit. The experimental data obtained were not sufficient for a precise test of the lower limit; however, these data did show the existence of a practical lower limit, at a value slightly larger than the predicted one.
A theoretical and experimental study of natural convection in a confined porous medium
Authors: Holst P. H. , Aziz K. 
Published: March 2009

AbstractNatural convection in a porous medium was mathematically modelled by writing force mass and energy balances on a differential element of porous medium. The resultant set of partial differential equations, which accounts for temperature‐dependent physical properties, was solved numerically after the introduction of a pseudo‐stream function. This method of treating emperature‐dependent fluid properties, which is also applicable to other fluid flow problems, resulted in an efficient solution algorithm. Good agreement has been obtained between theoretical and experimental results. Theoretical calculations show that under certain conditions variation of fluid properties with temperature has a significant effect on convective motions.
Determination of diffusion coefficients for M‐nitrobenzene sulphonic acid with a rotating disk electrode
Authors: Postlethwaite J. , Ong K. L. , Pickett D. J. 
Published: March 2009

AbstractThe cathodic reduction of m‐nitrobenzene sulphonic acid (sodium salt) 0.01, 0.1, and 0.5 M in 1 M H2SO4 has been studied at a rotating copper disk electrode. The limiting current densities were found to be mass transfer controlled and the diffusion coefficients determined from these values using the Levich equation are compared with the results obtained by others using a polarographic technique and the Ilkovic equation.
A general matrix method for the steady state solution of complex distillation assemblies
Authors: Harclerode Howard , Gentry James W. 
Published: March 2009

AbstractAn algorithm for the solution of El‐block band matrices is derived and the number of calculations and the required storage capacity are determined. The algorithm was developed for the solution of multi‐column distillation assemblies.The algorithm was applied to a three column, 5 component system in which the three reflux ratios and the three bottom compositions were specified. It was found that convergence was not influenced by the initial composition estimates or the assumed flow rates.
Continuous foam separation and activated carbon filtration to clarify dilute colloidal suspensions
Authors: Grieves Robert B. , Bewley Jerry L. 
Published: March 2009

AbstractA 380 gal/day (1.0 liter/min) foam separation‐activated carbon filtration unit, designed from a laboratory‐scale unit, has been tested with naturally‐occurring suspensions of sand, clay, and humus containing up to 210 mg/l suspended solids. Foam separation results have been subjected in detail to stepwise, multiple, linear repression analysis, yielding the ratio of the effluent to the feed particulate concentration as a power function of the feed surfactant concentration and the volume of air required per unit volume of feed clarified. The total operating cost function, including surfactant, air, and the capacity of the granular activated carbon, can be minimized, with operating costs from 38 to 97¢/1000 gal. for feed suspensions containing 35 to 210 mg/l suspended solids. Scale‐up factors are included.
Estimation of pressure effect on binary azeotropic compositions
Authors: Ruether J. A. , Lu B. C. ‐Y. 
Published: March 2009

AbstractAn explicit method for expressing the temperature dependence of liquid activity coefficients is applied to the estimation of the pressure effect on binary azeotropic compositions. The method is based on the assumption that at fixed composition the partial molal heat of mixing is a linear function of temperature. As a consequence the logarithm of the activity coefficient is expressed in the form (a+b/T+c log T). The estimated results for three systems tested agree well with the reported experimental values, the agreement being better than that obtained with the available methods in the literature.
Perturbation theory and one‐fluid corresponding states theories for fluid mixtures
Authors: Smith William R. 
Published: March 2009

AbstractA family of perturbation theories is defined which gives rise rationally, in zeroth order, to an infinite number of sets of corresponding states theories of the one‐fluid type, for solutions of molecules whose potentials are conformal. It is argued that the optimum zeroth order member of this family yields the highly successful one‐fluid van der Waals (vdWl) theory. This places that theory on a firm theoretical foundation and enables it to be systematically extended. The theory is derived to the second‐order terms and preliminary numerical results are presented for the case of hard‐sphere mixtures. Suggestions are made for empirical evaluation of some of the exact expressions.
Application of a modular computer simulation system to the control of a reactor train
Authors: Ponton J. W. , Johnson A. I. , Browne P. 
Published: March 2009

AbstractA modular, digital computer program, called DYNSYS, has been used for the simulation of the transient behaviour of a digester train for the extraction of alumina from bauxite. The modules, including digester units, pumps, slurry mixers, and conventional three mode controllers with control devices can be assembled in a flexible manner to simulate alternative control strategies for the train. Algorithms for a supervisory digital control computer adjusting set points and controlling process variables can also be tested. Methods for simulating fluctuations in process variables, including drift in sensing devices, were studied and improved control arrangements and settings were developed.A modular, digital computer program, called DYNSYS, has been used for the simulation of the transient behaviour of a digester train for the extraction of alumina from bauxite. The modules, including digester units, pumps, slurry mixers, and conventional three mode controllers with control devices can be assembled in a flexible manner to simulate alternative control strategies for the train. Algorithms for a supervisory digital control computer adjusting set points and controlling process variables can also be tested. Methods for simulating fluctuations in process variables, including drift in sensing devices, were studied and improved control arrangements and settings were developed.
Synthesis of optimal energy recovery networks using discrete methods
Authors: Menzies M. A. , Johnson A. I. 
Published: March 2009

AbstractA flexible modular program system for the synthesis of optimal energy recovery networks is described. Process networks are generated to meet both stream temperature and pressure specifications. The system makes use of a price based decomposition algorithm for sub‐process integration. It incorporates heuristic decision making and employs a “branch and bound” combinatorial technique for optimization of network configuration. The ability of the system to generate very realistic process designs is demonstrated by its application to the design of an energy recovery system for an ethylene plant with its associated refrigeration facility.
Entrance effects in liquid film flow
Authors: Ault Joseph W. , Sandall Orville C. 
Published: March 2009

AbstractFinite difference numerical solutions have been obtained to the Navier‐Stokes equations for entry‐region flow in a falling liquid film issuing from a slot. The iterative method developed does not neglect surface tension forces, however the effect of surface tension on the film acceleration is shown to be small. The results show a smooth transition between the initial velocity profile and the final fully‐developed profile. The starting length, defined as the distance required for the surface velocity to reach 95% of its final value, is on the order of 20 times the initial film thickness and increases with Reynolds number. A comparison of the calculations with available experimental data shows fair agreement.
Holdup in vertical two and three phase flow Part II: Experimental investigation
Authors: Bhaga D. , Weber M. E. 
Published: March 2009

AbstractExperimental data on air‐water‐glass beads system flowing cocurrently and countercurrently in a vertical column 1.5‐in. ID and 5‐ft. long at 1 atm. and room temperature are presented. The ranges of variables studied were: superficial gas velocity 0 to 2.55 cm/sec upward, superficial liquid velocity 7.6 cm/sec downward to 32.2 cm/sec upward, input solid concentration in the the slurry 0 to 6% by volume and the mean diameter of solid particles 0.0118 and 0.0059‐in. All flows involving gas were in the bubbly regime. The experimental data were in good agreement with the theory presented in Part 1.
Étude expérimentale sur le court‐circuit de l'alimentation dans un réservoir imparfaitement agité en régime continu
Authors: Paquet M. , Cholette A. 
Published: March 2009

AbstractLes auteurs montrent l'influence de plusieurs paramètres sur l'intensité du court‐circuit, dans un réservoir imparfaitement agité en régime continu. On a utilisé plusieurs formes d'agitateurs, plus particulièrement l'hélice de type marin.De façon génerale, le court‐circuit diminue quand la vitesse de l'agitateur augmente. Aux faibles vitesses, toutefois, le court‐circuit est souvent supérieur à celui qui existe quand l'agitateur est au repos. On explique la nature du court‐circuit maximum qui se manifeste à une certaine vitesse de l'agitateur.L'intensité du court‐circuit diminue en général lorsque le diamètre de l'agitateur augmente et quand la distance entre l'entrée et la sortie augmente. Par contre, le court‐circuit augmente avec le débit.En présence de chicanes, le court‐circuit est peu ou pas influencé par la largeur, la position et l'inclinaison des chicanes.
Theory of gas solubility in mixed solvent systems
Authors: Tiepel E. W. , Gubbins K. E. 
Published: March 2009

AbstractA simplified form of perturbation theory for mixtures is applied to the prediction of gas solubility in mixed solvent systems. A method for the determination of Henry's Law constants for gases as a function of solvent composition for any general multicomponent solvent mixture is presented. The theory requires molecular parameters and solvent density to predict the gas solubility. For the accurate prediction of solubility of complex molecules if is necessary to use gas solubility data for the pure solvent; however, solvent mixture activity coefficient data are not required. Comparisons with experimental results indicate that the theory works well for both polar and nonpolar solvent mixtures, provided that the dissolved gas does not chemically combine or associate with the solvents.
Sampled‐data feedback control of a binary distillation column
Authors: Shunta J. P. , Luyben W. L. 
Published: March 2009

AbstractThe design of sampled‐data controllers for a binary distillation column was studied for several types of controllers and for various control tray locations, sampling rates and disturbances. Minimal prototype control was superior to continuous PI control under some conditions but, as expected, was only satisfactory for a specified disturbance.dual “A” control scheme that compensates for both setpoint and load disturbances was developed. Two separate algorithms are implemented simultaneously, one receiving its input signal from the setpoint and the other from the measured variable. Dual control is superior to continuous control, particularly when both disturbances are encountered at the same time, and is superior to the “switching” method proposed by Mosler et al.
Adaptation of van der waals equation of state to the gaseous and liquid behavior of argon: Its application to simple substances
Authors: Daniil A. , Thodos George 
Published: March 2009

AbstractUtilizing the fact that the co‐volume parameter, b = vc/3, van der Waals equation of state has been reduced to the form

where β = a/Pcv2c and z = Pcvc/RTc. PVT data for argon, extending into the liquid region, have been utilized to establish the cohesive pressure parameter a as a function of temperature and density. This dependence is expressed in equation form and has been used to predict the PVT behavior of argon in its gaseous and liquid states, with an average deviation of 1.35% (250 points). The deviations resulting from this relationship for substances having similar zc‐values (zc ≈︁ 0.291) were found to be of this order of magnitude.
Prediction of vapor — liquid equilibria: Derivation of a new expression for vapor — liquid equilibrium correlations
Authors: Andiappan A.N. , Mclean A. Y. 
Published: March 2009

AbstractTo replace the interchange energy between two different types of molecules, two types of local energy parameters derived from Scott's two liquid concept are defined. When this definition is introduced into the quasichemical approximation, a new expression for correlating vapor‐liquid equilibria in binary systems results. The new expression is semi‐empirical in nature and for a binary system, it contains two adjustable parameters and a binary constant which are obtained from binary experimental data. It has been shown that the new expression can be used as a two‐parameter equation. Its application was tested with thirty‐four examples of highly non‐ideal systems, including twenty‐two systems at isobaric and twelve systems at isothermal conditions. Application to partially miscible systems is also examined. The results, correlated through the new expression, are compared with those obtained using the equations of Wilson and of Renon. The significance of the parameters of the new expression is discussed.
Transient freezing in laminar tube‐flow
Authors: Martinez Eugene P. , Beaubouef Richard T. 
Published: March 2009

AbstractA new model is presented for treating transient freezing in laminar tube‐flow. The liquid motion is constrained by requiring head‐loss versus flow‐rate to match that of a linear pump‐characteristic curve. This feature enables the model to describe freezing conditions which may lead to occlusion of the tube with solid‐phase material.The results demonstrate the sensitivity of tube occlusion both to temperature and liquid‐pumping capability. Both steady‐state and transient results obtained compare favorably with those found in the literature, which include an exact steady‐state solution. Maximum error is estimated at 15%.
Stockmayer force constants for the viscosity of polar gases
Authors: Malek Kader R. , Stiel Leonard I. 
Published: March 2009

AbstractRelationships have been developed for the calculation of the viscosity of a polar gas at atmospheric pressure from macroscopic parameters available for the substance. The molecular force constants for the Stockmayer potential determined by Monchick and Mason from viscosity data were related to the critical constants of the substance and the parameters ω and × defined through the vapor pressure. For 10 polar gases, an average deviation of approximately 3.0% was obtained between experimental viscosities and values calculated with the relationships of this study. The relationships were also utilized to calculate diffusion coefficients for a number of polar binary mixtures.
Transport properties of chain molecules and the theorem of corresponding states
Authors: Doan M. H. , Brunet J. 
Published: March 2009

AbstractPrigogine's corresponding states approach to equilibrium properties of pure r‐mers is extended to include transport properties. For r‐mer molecules, besides the alike element pair potential parameters, additional quantities are required to characterize the geometrical structure of the molecule and thereby describe more adequately pair potential interactions. As an example, the theory is applied to the homologous series of liquid n‐alkanes. The characteristic parameters for each member of the homologous series are determined using pure component viscosity data at one atmosphere and pure component denstiy data at one temperature and atmospheric pressure. The technique correlates pure component r‐mer transport properties (viscosity — 981 points, thermal conductivity — 216 points) over a wide range of temperature and pressure within experimental error. Using the present technique, available self‐diffusion coefficients are also correlated.
The density and phase behavior of some binary Hydrocarbon—Nonhydrocarbon systems using new mixing rules for the BWR equation of state
Authors: Bishnoi P. R. , Robinson D. B. 
Published: March 2009

AbstractThe applicability of the new mixing rules recently formulated by the authors for the BWR equation of state was assessed by predicting the densities of several binary mixtures of hydrogen sulphide with methane and ethane and the phase behavior of the carbon dioxide‐propane, hydrogen sulphide‐methane, hydrogen sulphide‐propane and hydrogen sulphide‐carbon dioxide binary systems. The predictions confirmed the effectiveness of the new rules for predicting the densities of hydrocarbon‐non‐hydrocarbon binaries, and they showed that acceptable accuracy could be obtained in predicting the phase behavior of difficult binary systems even when no phase behavior data are used for evaluating the parameters in the equation of state.
A single parameter equation for the prediction of multicomponent vapor‐liquid data from binary isobaric data
Authors: Hankinson Risdon W. , Langfitt Bruce D. , Tassios Dimitrios P. 
Published: March 2009

AbstractA single parameter Wilson equation that is suitable for use with isobaric systems is presented. Parameters for both the original and modified equations are obtained from isobaric binary data and from infinite dilution activity coefficients and then used to predict multicomponent vapor‐liquid data for systems up through a quinary. Satisfactory results were obtained from the use of infinite dilution activity coefficients and the sensitivity of the final result to the accuracy of these end points is discussed.
The diffusivity of hydrogen in liquid aminomethane
Authors: Kalra H. , Moore R. G. , Otto F. D. 
Published: March 2009

AbstractMass transfer studies in a single phere absorber were used to determine the diffusivity of hydrogen in liquid aminomethane over the temperature range —20°C to —30°C. A modified Ferrell and Himmelblau correlation derived from diffusion data for hydrogen in ammonia and in aminomethane is recommended for use in estimating the diffusion coefficients for hydrogen, hydrogen deuteride and deuterium in aliphatic amines when experimental data are not available.
A dynamic analysis of a packed gas absorber
Authors: Bradley K. J. , Andre H. 
Published: March 2009

AbstractAn experimental and theoretical investigation of the unsteady‐state operation of a pilot‐scale packed gas absorption column was made. Carbon dioxide was removed from an air‐carbon dioxide was removed from an air‐carbon dioxide mixture into an aqueous monoethanalamine solution by absorption accompanied by chemical reaction.A numerical simulation of the contactor response to variations in feed flowrates and compositions based on the method of characteristics, successfully predicted the experimentally determined responses within the range of repeatability of the experiments.
Surface viscosity measurements by an improved rotational‐torsion method
Authors: Moo‐Young M. , Vocadlo J. J. , Charles M. E. 
Published: March 2009

AbstractA new double‐ring rotational‐torsional surface viscometer is described. It is shown that this represents an improvement of the conventional single‐ring device since secondary flow effects on viscosity measurements can be minimized or eliminated. Experimental results for some aqueous polymer solutions show that these effects can be substantial.