bluuebunny/crossref_metadata_2025 huggingface dataset:
The flow of “settling” slurries in tubes with internal spiral ribs
Authors: Charles M. E. , H‐S CHEH C. , H‐L. CHU L.
Published: March 2009

The secondary flows created by an internal spiral rib in an otherwise conventional smooth tube are illustrated by reference to the axial, and combined tangential and radial velocity components for a fluid flowing in a 2‐inch diameter tube containing a rib with a pitch‐to‐diameter ratio of 3

The effect of such secondary flows on the transportability of “settling”(suspensions)was investigated by measuring pressure gradients for the flow of two sand/water slurries in a smooth 2‐inch tube and in 2‐inch diameter tubes with ribs of pitch‐to‐diameter ratio 5.15, 3.32 and 1.80. Average flow velocities ranged from 0.5 to 8 feet/sec. and delivered concentrations ranged from 5 to 18 per cent by volume

While the ribs were found to be a disadvantage at relatively high average mixture velocities because of increased pressure gradients, they were found to be advantageous at relatively low velocities, i.e. velocities less than the critical deposit velocity for flow in the smooth tube, in that the pressure gradients, for a given sand/water slurry with a given delivered concentration and average velocity, were lower in the ribbed tubes than in the smooth tube. Because of this, the power consumption per unit mass of solid transported was reduced by the presence of a rib. The optimum pitch‐to‐diameter ratio was estimated to be about 5

Pressure gradients measured for one of the slurries with air added as a third phase showed the presence of air to be a definite disadvantage
Waste water treatment by solvent extraction
Authors: Kiezyk P. R. , Mackay D.
Published: March 2009

A review is presented of the application of solvent extraction to the treatment of waste waters. Methods of extraction, solute‐solvent separation and water — solvent separation are described. Phenol removal, oily water treatment, desalination, metal recovery by “liquid ion exchange” and miscellaneous other applications are described/ Available economic data are discussed. Possible future applications are outlined and it is suggested that greatest potential is in the treatment of oily waste water and of relatively concentrated streams containing valuable or noxious materials
Experimental design for the determination of coefficients in coupled non‐symmetric first order systems: The multicomponent diaphragm cell
Authors: Kosanovich George , Cullinan Harry T.
Published: March 2009

The diaphragm cell method for experimentally determining multicomponent liquid diffusivities is optimized. An exact matrix solution of the coupled, non‐symmetric, first order, linear, differential equations which presents a slightly different viewpoint is given. Optimum experimental conditions are defined for ternary systems for both single determinations and multiples of a single determination. The methods used can be applied to any number of components
Diffusion of positive chlorine in macroreticular resins
Authors: Dewar Edgar J. , Wayman Morris
Published: March 2009

The diffusion of chlorine in macroreticular chlorine exchange resins was studied by measurement of: (1) experimental concentration‐distance profiles, and (2) overall effective diffusion coefficients D̄. The results were compared to demonstrate that the second method, although simpler, yielded useful results. The transfer mechanism was shown to be pore diffusion where chlorine first diffused into the resin through the pores before being absorbed into the resin around them. Pore diffusion models yielded pore diffusion coefficients Dp of 3.1 x 10‐5 to 7.5 x 10‐5 cm2/sec. The rate of absorption was controlled by coupled diffusion but the film resistance became negligible after a short time. Effective (D̄) and concentration‐dependent (Ds) diffusion coefficients in the solid phase were in the range of 10‐9 to 10‐ cm2/sec
A laser interferometric method for electron concentration measurements in stabilized plasmas
Authors: Meubus Paul , Fortin Marc
Published: March 2009

This work presents an interferometric means for measuring electron concentrations between 1012 and 1016 electrons per cm3 in a stabilized ionized medium and an Argon plasma is used to illustrate the method. The interferometer is a 100 mW He‐Ne laser emitting at 6,328 Å and 3.39 microns and a movable mirror is used to obtain the interferometric fringes required for calculation of the electron concenrations in the plasma

The method uses the interesting feature of the He‐Ne laser that both emissions at 6,328 Å and 3.39 microns originate at the same upper level so that variations in the 3.39 microns emission modulate the visible light (6,328 Å) output. This property has been used by a number of authors for measurements on plasmas in transient conditions; this paper presents an application of the method for stabilized plasmas, thus broadening the field of application
Diffusion effects in catalytic gas oil cracking
Authors: Best D. A. , Pachovsky R. A. , Wojciechowski B. W.
Published: March 2009

Wojciechowski's four parameter model of catalyst decay is applied to conversion data for gas oil cracking over a diffusion limited catalyst. The parameters thus obtained are compared with those obtained previously for a diffusion free form of the same catalyst, cracking the same feed stock under identical experimental conditions. The comparison shows that the presence of diffusion affects not only the rate of catalytic cracking but also the rate of aging. It is also shown that the introduction of diffusion phenomena has no effect on the mechanism of aging. The presence of diffusion limitations however has the effect of making the feed stock appear more homogeneous in reactivity
Prediction of excess free energies of liquid mixtures by an analytical group solution model
Authors: Ronc M. , Ratcliff G. A.
Published: March 2009

The group solution model of Ratcliff and Chao for the excess free energies of liquid mixtures has been put in analytical form using the Wilson equation. This procedure obviates some of the limitations and inaccuracies of the previous model, and is well suited to computer calculation. It was tested and found satisfactory for a wide range of mixtures containing the groups methylene and hydroxyl

Group Wilson parameters were generated from experimental data for methylene/hydroxyl mixtures at 25°C to 95°C, and are given by

At temperatures within or close to this range, these parameters allow the prediction of excess free energies of binary or multicomponent mixtures containing these two groups. No experimental data are required. Good results are obtained for aqueous systems.
Misinterpretation of shrinking core data in chemical reactions
Authors: Bowen J. H.
Published: March 2009

Some kinetic data for the reduction of ferrous chloride with hydrogen have been reexamined using a diffuse interface model of chemical reaction. An energy of activation has been calculated, approximately twice the “apparent value” originally reported
Fluid dynamics and flow patterns in stirred tanks with a turbine impeller
Authors: Desouza Abel , Pike Ralph W.
Published: March 2009

Velocity profiles were measured in a stirred tank with a turbine impeller using a three‐dimensional, pitot tube probe. A tangential jet model was used to describe the flow in the region of the impeller, and two‐dimensional potential flow models and a circular jet were used to describe the flow in the rest of the tank. The tangential jet model accurately predicted the measurements from this work and comparable measurements reported in the literature for water and air, for varying impeller diameter and speeds and for different tank diameters. In the rest of the tank a three‐dimensional, low velocity, flow field exists; and the center of circulation is not a true stagnation point. The flow at this point is tangential. The two‐dimensional models only qualitatively described the flow in this region, and a three‐dimensional model would be required. It was experimentally and theoretically confirmed that standard practice of using 10% baffles effectively controls the flow in the tank.
Étude en régime non laminaire du mouvement d'une goutte dans un milieu pulsé
Authors: Chonowski A. , Angelino H.
Published: March 2009

In the first part of the work, the authors have experimentally studied the fall rate of single drops of chlorobenzene with different diameters into a water column subjected to strictly sinusoidal pulsations. It has been shown that there is always a retarding effect and that, in certain cases, the average speed in a pulsated medium may be much lower than the one measured in a motionless medium.

In the second part of the work, the authors have made a theoretical analysis of the motion of a drop in a pulsated medium. An equation is suggested for describing that motion, which results from the analysis of the forces in which the drag coefficient is modified in order to take into account the dynamic effects. The aforesaid equation has been systematically solved by means of analog and digital computers and the results, which have been compared with the experimental data, agreed very well with the latter, the deviation being less than 1.18%.
Fall of drops in non‐newtonian media
Authors: Mohan V. , Nagarajan R. , Venkateswarlu D.
Published: March 2009

Terminal velocities of drops of organic liquids of diameter 0.0726 to 0.7256 cm in polymer solutions are determined. The Reynolds number range covered is 0.1 to 103. Visual observations on the shapes and oscillations of drops are reported. A correlation for the terminal velocity data is presented.
Heat transfer from a horizontal tube to a fluidized bed in the presence of unheated tubes
Authors: Lese H. K. , Kermode R. I.
Published: March 2009

An experimental study of heat transfer from a horizontal tube to a fluidized bed was carried out in the presence of nearby unheated tubes. The effect of the number of tubes, their size, configuration, and the type of fluidized materials was studied. Certain configurations caused as much as a 56% reduction in heat transfer over the most favorable case. The top of the tube was covered by stagnant solids, the bottom partially by a gas film, and the sides by a small region of vigorously agitated solids. Most of the heat transfer occurred in the side region. An overall heat transfer coefficient of 35 Btu/hr‐ft2‐°F. was found at the best conditions.
Mass transfer from a single gas bubble
Authors: Weller K. R.
Published: March 2009

Gases covering a wide solubility range were used to measure absorption rates from single bubbles rising freely in water. Absorption rates were not sensitive to any power of the diffusion coefficient and solubility alone proved to be an adequate correlating parameter.

Experiments with bubbles containing inert and soluble gas mixtures yielded no evidence for a gas‐film resistance, confirming published theory.

Results for the absorption of CO2 by NaOH solutions correlated well with the theory for pseudo‐first‐order fast reactions, provided allowance was made for a decreasing “physical” solubility of CO2 with increasing ionic strength of the solutions.
Effect of channeling on the performance of adiabatic flow tank reactors for exothermic reactions
Authors: Lo S. N. , Cholette A.
Published: March 2009

The performance of CSTR's can be affected significantly by the presence of channeling, for irreversible exothermic first and second order reactions, under adiabatic conditions. Theoretical curves exhibit the variation of the conversion with residence time, for different channeling intensities and various values of the kinetic parameters. A certain degree of channeling can be greatly beneficial to the reactor performance, especially when the activation energy and heat of reaction are high, where multiple steady states can exist. For second order reactions, the ratio of the initial concentrations of A and B, considered as a parameter, plays a role similar to that of the kinetic parameters.
Experimental study on the optimum performance of an adiabatic MT reactor
Authors: Lo S. N. , Cholette A.
Published: March 2009

The performance of an adiabatic MT reactor has been studied under various experimental conditions, using the reaction between hydrogen peroxide and sodium thiosulphate. Following the M‐section, consisting of a CSTR, the T‐section was made up of a large number of small stirred tanks in series.

The same general condition for optimizing the MT model, that the reaction rate in the M‐section be a maximum, is shown to apply when maximizing the conversion for a given residence time as it was shown previously to apply when minimizing the residence time for a given conversion.

Very good agreement is shown between theoretical and experimental results, confirming the superior results often obtained with an MT combination as compared with those given by a stirred tank or a tubular reactor under similar conditions. Bi‐stable steady states of conversion have been achieved and their effect shown on the performance of the combined reactor.
The mechanism of the adsorption of alkyl xanthate species on galena
Authors: Wells P. F. , Nagy E. , Cleave A. B. Van
Published: March 2009

Oxidation of galena produced thiosulphate and sulphate ions at the mineral surface but flotation activity, using isopropyl xanthate as collector, was found to depend on the concentration of thiosulphate ions at the surface. It is proposed that the thiosulphate ion reacts with di‐isopropyl dixanthogen formed by oxidation of xanthate ion in solution. It was demonstrated that these species react in homogeneous solution to give xanthate and xanthogen‐thiosulphate ions. The proposed surface reaction may account for the formation of a layer of adsorbed xanthate ions and for the surface redox potential being raised to a value where more xanthate ions can be chemisorbed and where dixanthogen is stable.
Theory of diffusion of gases in protein solutions
Authors: Jalan V. M. , Tham M. K. , Gubbins K. E.
Published: March 2009

A theory based on a rigid sphere model is presented for the diffusion coefficient of dissolved gases (and liquids) in protein solutions. The only quantities needed in order to make calculations are the rigid sphere diameters and the solution density; methods are given for obtaining the diameters.

The theory predicts that the ratio of the diffusion coefficient of the gas in protein solution to that in pure water is strongly dependent on the size of the protein molecule, but is insensitive to the properties of the solute gas. The theory gives good agreement with available experimental data for the effects of protein concentration and molecular properties on the diffusion coefficient.
On the theory of dynamic plug‐flow processes: Inlet control and distributed trajectory control
Authors: Bailey J. E.
Published: March 2009

Topological methods are applied in a study of the periodic operation of plug‐flow processes. Attention is focused on periodic processes, but the results are shown to apply to other important situations. Three combinations of control options are considered and compared. Attainable sets for each case are characterized. The theory describes comparisons between steady state and time‐varying controls and the à priori structure of optimal control.
Diffusion of binary organic liquid mixtures across polyethylene
Authors: Tombalakian A. S. , Markarian G. K.
Published: March 2009

A study of the diffusion of binary organic liquid mixtures across a polyethylene membrane, induced by pressure and chemical potentials, has been made. The volume flows have been interpreted using the theory of irreversible thermodynamics in terms of a linear phenomenological equation. This relationship has been used to estimate the magnitudes of the phenomenological coefficients for volume flow across the membrane. The reflection coefficient, which is a measure of the membrane selectivity, has been evaluated for the various interdiffusing species. The dependence of the phenomenological and reflection coefficients on temperature for the various binary organic liquid systems has been determined.
Effectiveness factors for immobilized‐enzyme reactions
Authors: Moo‐Young M. , Kobayashi Takeshi
Published: March 2009

The effect of intraparticle diffusion in artificial membranes on the kinetic behavior of immobilized enzymes has been considered theoretically in terms of an effectiveness factor. When the immobilized enxymes obey a Michaelis‐Menten relationship, an approximate equation is proposed for the effectiveness factor. For a substrate inhibited enzymatic reaction, the effectiveness factor may exceed unity and display multiple steady‐state behavior. Thus, the over‐all rate of reaction in the artificial membrane is faster in this case than that when the substrate concentration in the interior is at the same as that at the exterior surface. In the case of a product inhibited enzymatic reaction, the effectiveness factor is always less than that which corresponds to a Michaelis‐Menten relationship.
The effects of extruder variables on the gelatinisation of corn starch
Authors: Lawton B. T. , Henderson G. A. , Derlatka E. J.
Published: March 2009

The 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

Carbon 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

Solutions 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

Measurements 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

On 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

Natural 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

The 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

An 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

A 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

An 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

A 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

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.

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

A 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

Finite 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

Experimental 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

Les 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

A 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

The 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

Utilizing 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

To 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

A 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

Relationships 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

Prigogine'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

The 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

A 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

Mass 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

An 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

A 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.
A creeping flow model of a deformable drop approaching a plane interface
Authors: Feuerstein I. A. , Chappelear D. C.
Published: March 2009

A new model has been formulated and analyzed which accounts for the deformation of a drop in response to the pressure distribution in the draining film between it and a rigid plane. The rate of approach is related to the pressure distribution and drop shape. When the nonlinear partial differential equations are written in dimensionless form, one dimensionless group, β = Δρgb/σ2, arises which represents the ratio of gravity forces to surface forces. Only β need be specified to solve these equations; viscosity enters only as a scaling factor on time. The equations were simplified to ordinary differential equations by assuming that the rate of change of shape was small relative to the change in position. Numerical soliitions were obtained from β = .15 to 10−3 using an iterative Runge‐Kutta procedure at each separation.
Falling coaxial cylinder viscometry of polymer melts
Authors: Sato Kyosaku , Rudin Alfred , Chee K. K.
Published: March 2009

This article considers possible erxors in experiment or analysis and alternative methods of data treatment for a falling coaxial cylinder viscometer. The viscometer uses a weighted rod falling into a polymer melt contained in a closed end concentric cylinder. Flow relations can be solved for non‐Newtonian fluid response in steady, simple shearing flow. Although the rod fall is found not to be steady, as assumed, this produces negligible error in the computed flow curves. Consistent flow curves which were independent of apparatus geometry were obtained by a method in which instantaneous rod velocities were estimated graphically from raw data and an end correction was taken into account.
Axial pressure profiles in non‐newtonian flow: Part I: Theoretical and experimental considerations
Authors: Blum David B. , Yerushalmi Joseph , Williams David J.
Published: March 2009

The flow behavior of polymeric fluids in tubes can be determined from measurements of the radial stress profile in the flow direction. This subject, the focus of our research, will be examined in Part II of this communication.

Part I describes a research designed to test the accuracy of stress measurement with pressure transducers in a variety of recess mount geometries. No mount geometry errors were detected for the fluids used in this work over a shear rate range of 1 to 2000 sec−1. Part I also contains a survey of the literature and theoretical considerations pertinent to the entire work.
Axial pressure profiles in non‐newtonian flow: Part II: Viscometric flow and relaxation phenomena analyses
Authors: Blum David B. , Yerushalmi Joseph , Williams David J.
Published: March 2009

Extensive pressure profile data were compiled for a 16.5% polyisobutylene solution in mineral spirits. Values of stored elastic energy obtained from these data compare favorably with those ascertained from die swell and from entrance correction methods. The viscometric normal stress differences were significantly larger than the shear stress and, particularly, the second normal stress rose to a maximum where it was an order of magnitude larger than the first normal stress difference. Time constants calculated from swell decay and entrance‐borne elastic stress relaxation are essentially the same and show an approximate inverse relation to the shear rate.
A new semi‐continuous dilatometer
Authors: Janssens Jean‐Marie , Ruel Maurice
Published: March 2009

A new semi‐continuous dilatometer which does not have the major drawbacks of the previous model was designed, constructed and tested, using the systems benzene‐cyclohexane and cyclohexane‐ethanol. The volumes of mixing of five systems made of n‐alcohols and cyclohexanc: were determined at 25°C.
Mechanism of elutriation from fluidised beds
Authors: Guha S. K. , Kumar A. , Gupta P. Sen
Published: March 2009

Elutriation can be used as a convenient method for classification of particles. However, it has been observed that complete elutriation is not possible. Elutriation stops when the concentration of the elutriating component in the bed reaches an equilibrium value. The rate equation for elutriation has been found to be analogous to that of a first order reversible chemical reaction.

In this paper two correlations—one for evaluating the equilibrium bed concentration and the other for the elutriation rate constant have been proposed by relating these quantities with the relevant system parameters.
The influence of design and operating variables on energy consumption and separation efficiency of a hydrocyclonic concentrator
Authors: Hsiang Thomas C. H. , Woods Donald R.
Published: March 2009

The problem of physical separation of solids from liquids in very dilute concentrations by hydrocyclone concentration is considered in two parts. First, the effect of feed concentration, volume split, feed flowrate, cone angle, inlet diameter and vortex finder length on separation efficiency and energy loss are investigated. The relationship between the separation efficiency; and the energy loss is also studied.

Secondly, the effect of three different designs of body shape on the separation efficiency and energy loss is investigated.

In this study statistical concepts are used extensively in the design of experiments and the analysis of experimental results.
The hydrogenolysis of n‐butane on a nickel on silica catalyst: I A Kinetic model
Authors: Orlickas A. , Hoffman T. W. , Shaw I. D. , Reilly P. M.
Published: March 2009

The catalytic hydrogenolysis of n‐butane was investigated in an integral packed bed reactor (0.70 cm. ID by 25 cm. long). The catalyst was 10% nickel on silica gel. A block factorial set of experiments was performed at hydrogen‐to‐butane feed ratios of 4. to 9., temperatures of 240° to 282°C and feed flowrates of 1.0 to 1.8 ml/sec. The predominant reaction appeared to be the remad of terminal methyl groups.

Kinetic rate expressions were developed to predict the product distribution, taking into account a five‐fold change in catalytic activity. A parameter estimation strategy,applying non‐linearregression theory, was used to obtain the ten kinetic parameters. Error analysis of the parameters was performed using likelihood ratios. Models were developed to describe the catalyst activity changes observed during experinrentation. The kinetic model predicts the experimental observations very accurately over all conversions and shows some deviation only at the combination of high temperature and low feed ratio.
Multiproperty analysis of PVT, enthalpy and phase equilibrium data
Authors: Lin Chen‐Jung , Kwok Y. C. , Starling K. E.
Published: March 2009

In the most general application yet made of the method, multiproperty analysis was used to determine methane and propane parameters for a modified BWR state equation. Over 1300 mixture and pure component data points for density, enthalpy, vapor pressure and vapor‐liquid equilibrium, from −290°F to 400°F and up to 9,000 psia, were used in the multiproperty repression calculations. The resultant equation of state predicts thermodynamic properties with low average absolute uncertainties: 0.0055 lb‐mole/cu. ft. (0.77%) for density, 1.01 Btu/lb for enthalpy, 0.0147 Btu/lb‐ °F for entropy, 0.62% and 0.63% respectively for methane and propane vapor pressures and 1.67% and 3.73% respectively for methane and propane K‐values.
Dynamics of cyclic fixed bed ion exchange with counter‐current regeneration: An analysis based on a linear mass transfer model
Authors: Tan K. S. , Spinner I. H.
Published: March 2009

Solutions are given for the transient and cyclic steady state performance of fixed bed ion exchange when operated with counter‐current regeneration. A mass transfer model which makes use of linear isotherms and linear driving force rate equations is applied in obtaining the solutions to this boundary value problem. Explicit calculation methods for large time parameter systems and implicit methods for small time parameter systems are illustrated. The model is found to predict adequately the experimental results for a sea water softening process.