bluuebunny/crossref_metadata_2025 huggingface dataset:
The turbulent flow characteristics of model fibre suspensions
Authors: Bobkowicz A. J. , Gauvin W. H.
Published: June 2009

The pressure drop of aqueous model nylon fibre suspensions was determined in a vertical 2‐in. copper tube in the turbulent range as a function of velocity, fibre length‐to‐diameter ratio (L/D) and concentration. Fibre diameters ranged from 20.2 to 51.6 microns and length from 0.52 to 1.21 mm. A marked depression below the value for the pressure drop of water was observed at high L/D's and its magnitude increased with the solids concentration. For low L/D values the depression was almost negligible. An explanation is advanced for the depression in pressure drop based on alterations in the turbulence characteristics in the presence of fibres.
Calcination of fluid coke in an electrically heated fluidized bed
Authors: Paquet J. L. , Foulkes P. B.
Published: June 2009

Laboratory studies carried out by Alcan showed that fluid coke, being of consistent uniform spherical size, could easily be fluidized, with the fluidized bed being able to carry an electrical current. This discovery led Alcan people to the conclusion that electric calcination in a fluidized bed would be a most favorable method for calcining fluid coke.

It is the purpose of this paper to outline the main features of a one‐ton per hour pilot unit which was built to study this new calcination technique, and in particular to focus attention on the numerous problems that had to be solved before obtaining a successful operating unit.
The flow of suspensions through tubes IV: Oscillatory flow of rigid spheres
Authors: Shizgal B. , Mason S. G. , Goldsmith H. L.
Published: June 2009

The theory of oscillatory flow of a homogeneous liquid in a straight circular tube developed by Lambossy and Womersley has been confirmed by direct measurements of the displacement profiles for a sinusoidal pressure gradient at various frequencies.

Rigid spheres suspended in the liquid showed radial migration away from the walls and away from the tube axis when the particle Reynolds number was made sufficiently high. This is the analogue of the tubular pinch effect discovered by Segré and Silberberg for steady flow, and is also exhibited by concentrated suspensions.

The modification of the flow behavior of suspensions by Miperposition of an oscillatory pressure is briefly discussed.
Old and new problems in the field of vapor‐liquid equilibria
Authors: Redlich Otto
Published: June 2009

The present survey elaborates some of the topics discussed in an address presented at the 13th Canadian Chemical Engineering Conference in Montreal, October 23, 1963. Such a survey, of course, can mention only few of the important contributions of various authors that have elucidated the field of vapor‐liquid equilibria in the last twenty years.

Thermodynamic consistency is only briefly mentioned. Since activity and fugacity coefficients are used for quite different purposes it is better to define them differently without trying to maintain a formal analogy. Activity coefficients of non‐associating mixtures are satisfactorily represented by the traditional two‐parameter relations. For associated solutions, as a rule, an association function must be superimposed. Further development and testing of association terms is desirable. Progress in the systematic representation of interaction in solution is promising. Calorimetric measurements in recent years have made considerable contributions.
Saturated vapor and liquid densities of pure substances
Authors: Barile Ronald G. , Thodos George
Published: June 2009

Relationships between zR and PR have been developed for the prediction of the complete saturated vapor and liquid density curves of pure substances. The coefficients and exponents of these relationships were derived from the saturated densities of 23 polar and nonpolar substances and were found to depend on zc, the critical compressibility factor of each of these substances. Densities calculated with these relationships produced average deviations of 1.5% for the saturated vapor region and 2.7% for the saturated liquid region from 54 points considered for each substance.
Experimental determination of circulation velocities inside drops
Authors: Horton T. J. , Fritsch T. R. , Kintner R. C.
Published: June 2009

Velocities inside large drops suspended in a fluid flowing upward in a tapered glass tube were measured by darkfield particle trace photography. Drop Reynolds numbers were between 3.76 and 19. There was a slow decay of internal velocity and a change in circulatory pattern with the accumulation of minute amounts of colloidal impurities at the interface. The evidence indicates that streamlines leave the interface over the entire rear hemisphere of the drop as circulation is damped.
The electrical resistance of fluidized beds of coke and graphite
Authors: Graham W. , Harvey E. A.
Published: June 2009

The electrical resistance of beds of finely divided graphite and conducting coke have been investigated in the settled and fluidized regions.

In almost all cases a maximum in the bed resistance occurs at a gas velocity slightly greater than that required for minimum fluidizing. This has been explained qualitatively by assuming current flow along a continuous network of touching particles the resistance of which is modified by the growth of gas bubbles in the bed.
Pressure‐volume‐temperature behaviour of ethyl alcohol in the gaseous and liquid states
Authors: Bhattacharyya Dibakar , Thodos George
Published: June 2009

PVT data available in the literature for ethyl alcohol have been utilized for the development of a reduced density correlation for this substance. The critical constants accepted in this study are those determined by Young(1)Tc= 516.3°K, Pc= 62.96 atm, andpe= 0.276 g/cm.3. To extend the available PVT information for ethyl alcohol over the complete range of temperatures up to TR= 1.8 and pressures up to PR= 40, use has been made of the available reduced density correlation of ammonia(2)and the Nelson‐Obert compressibility factor charts(3).
Radioactive tracer experiments on large stirrers for liquid‐liquid contacting
Authors: Stemerding S. , Groothuis H. , Hoogendoorn C. J.
Published: June 2009

The use of radioactive tracer techniques for studying the flow through large‐scale plant reactors under operating conditions is illustrated by tests on a 530‐cu. ft. stirred vessel used for contacting a hydrocarbon and an aqueous stream. The two streams had to be traced simultaneously. Simple equations are given for calculating the phase holdup from pulse response curves.

It was found that the reactor, a vessel equipped with propeller stirrer and draught tube, contained a relatively large proportion of the heavier aqueous phase which even partly formed a dead zone at the bottom, when the propeller was pumping downwards. Reversal of the pumping direction resulted in an improved operation.
Experimental study of natural convective heat transfer from a vertical plate in a non‐newtonian fluid
Authors: Reilly I. G. , Tien Chi , Adelman Maurice
Published: June 2009

Experimental work was carried out for the study of natural convection heat transfer from heated vertical plate to a non‐Newtonian fluid. Successive correlations were obtained and the results agree substantially with the theoretical prediction.
The effect of changes in initial composition on the equilibria of solid‐gas systems
Authors: Storey S. H.
Published: June 2009

A method is given for calculating the change in the equilibrium composition of a multicomponent solid‐gas system at constant temperature and pressure directly from a given change in the initial reactant composition, thus avoiding the complete recalculation of the equilibrium for each new initial mixture. The method can also be used to calculate individual equilibrium compositions. Two examples of how the calculations should be set up are given.
Kinetics of the catalytic oxidation of isobutene
Authors: Mann R. S. , Rouleau D.
Published: June 2009

The air oxidation of isobutene was investigated over supported and unsupported copper oxide catalysts in an isothermal integral flow reactor. The effect of various variables, that is, ratio of oxygen to isobutene in the feed, process temperature, copper concentration on the catalyst and reciprocal of space velocity on the conversion and yield were determined.

Though several mechanisms were postulated, the rate of reaction was most satisfactorily correlated by a mechanism which assumes the rate controlling step as the surface reaction between strongly adsorbed isobutene and gaseous (weakly adsorbed) oxygen. A rate equation has been derived and the kinetic rate constant and adsorption constants for isobutene and methacrolein are reported as functions of temperature.
Treatment of hydrocarbon lubricating oil by sodium alloys
Authors: Sirianni A. F. , Alexander W. A. , Puddwgton I. E.
Published: June 2009

Sodium extended in the form of alloys with inert metals indicates marked acid neutralizing properties for hydrocarbon lubricating oil when the systems contain at least 20 atom percent sodium. Transparency of the treated oil correlated well with pH measurements.
Critical temperatures and pressures of the ethane–n‐heptane system
Authors: Ekiner Okan , Thodos George
Published: June 2009

The critical temperatures and critical pressures of the ethane—n‐heptane system have been established experimentally with a visual PVT cell which utilized mercury as the pressurizing medium. The information obtained from the relative hydrocarbon volumes of the vapor and liquid phases permitted the measurement of these critical values.

Five different binary compositions were used to establish the critical temperature locus and critical pressure locus for compositions of x2 ≥ 0.655. The critical constants obtained in this study have been compared with corresponding values from the work of Kay(1).
Absorption of ethylene by aqueous chlorine solution
Authors: Akehata T. , Johnson A. I.
Published: June 2009

A study has been made of the rates of absorption of ethylene into aqueous chlorine solutions. The results are reported graphically as enhancement factors which have been compared with the predictions of the Hatta theory and with a simple model based on slow chemical reaction and diffusion of the main reactants. At lower temperatures the proposed model provides a reasonable description of the reaction accompanied mass transfer and yielded a rate constant for the formation of ethylene chlorohydrin; at 20 °C. and above, the Hatta model is sufficient.

Studies were made using solutions with increased concentrations of hydrochloric acid and hypochlorous acid and the catalytic effect of glass and gas liquid surfaces was studied.
Influence of a falling thin liquid film upon a co‐currently flowing gas stream in a vertical duct
Authors: Pike John G.
Published: June 2009

A theoretical model of a gas stream flowing co‐currently with a liquid film is established. The model is used to analyse the experimental results obtained for the co‐current flow of an air stream and a thin water film in a vertical rectangular duct. The influences of the motion and non‐smooth nature of the film surface upon the air stream are isolated and values of equivalent sand roughness are determined.
The application of stereophotogrammetry to the measurement of interfacial waves
Authors: Charles M. E. , Lilleleht L. U.
Published: June 2009

A stereophotogrammetric technique is described which was used to measure amplitudes and wavelengths for wave patterns generated at the interface between two liquid layers flowing co‐currently in a closed rectangular conduit. In the preliminary experiments differences in the interfacial elevation due to the presence of Waves of amplitude as low as 0.2 mm. and wavelength of 75 mm. could be detected using this technique. Stereophotogrammetry having the advantage that no probes of any kind interfere with the flowing liquids may well become another useful tool in chemical engineering research.
The pipeline flow of paste slugs: I. Concepts and general flow behavior
Authors: Berkowitz N. , Brown R. A. S. , Jensen E. J.
Published: June 2009

Cylindrical paste segments, carried by a liquid hydrocarbon (such as crude petroleum), can be transmitted through pipelines in much the same manner as rigid capsules or ingots, and the technique may therefore offer a useful method for long‐distance bulk commodity transportation.

In this paper, basic concepts of paste slug conveyance are briefly discussed and a first detailed study—mainly concerned with general flow behavior and flow velocities of individual slugs in an experimental 1‐in. i.d., 70‐ft. long closed‐loop line—is reported. As a matter of convenience, attention is confined to the flow of coal paste segments (prepared from a 70:30 w/w coal‐water paste) in a refined light mineral oil (ρ = 0.829 gm./cc. and μ = 7.05 cp at 60°F.). Slug‐to‐pipe diameter ratios varied from 0.5 to 0.8, and fluid velocities ranged to 11 ft./sec. (corresponding to pipe Reynolds numbers up to ca. 12,000).
Isobaric binary vapor‐liquid equilibria system: Carbon tetrachloride‐tetrachloroethylene
Authors: Subbarao B. V. , Venkatarao C.
Published: June 2009

Vapor‐liquid equilibrium data are presented for the binary system, carbon tetrachloride‐tetrachloroethylene, at 760 ± 1 mm.Hg. total pressure using a modified Colburn equilibrium still. The system showed a tendency for ideal behavior. The experimental data have been correlated with the stepwise integration method of Othmer and with Hirata and Prahl correlations. Excellent agreement was obtained with Prahl correlation.
Reaction accompanied mass transfer between liquid phases
Authors: Seto P. , Furter W. F. , Johnson A. I.
Published: June 2009

Simple apparatus for studying the rates of transfer of esters such as ethyl acetate and ethyl formate across a plane surface into water and into caustic solutions is described. Quantitative measurements of the rate of transfer are reported.

In a semibatch operation using stirring in both phases, an unexpected retardation of the transfer of ethyl acetate into the reacting solutions was observed.

To investigate the phenomenon at the interface, reaction mass transfer studies with still phases were carried out. The use of Moiré patterns for observing the formation of a turbulent reaction zone and the concentration gradients in the aqueous phase has been studied. Factors influencing the rate of propagation of the reaction zone are discussed.
Combined free‐and‐forced convection: I. Heat transfer in aiding flow
Authors: Brown C. K. , Gauvin W. H.
Published: June 2009

A study of the rate of heat transfer to air at low velocities was performed in a heated stainless tube, 4.42‐in. inside diameter and 102‐in. long. The air flowed upward through the tube, under which conditions the buoyancy forces aided the forced flow. The investigation covered a Reynolds number range from 385 to 4,930, and nominal wall temperatures of 100, 500 and 950°C. For laminar aiding flow, the local Nusselt number could be correlated with (NGr/NRc). For turbulent flow, the local Nusselt number was correlated with the Grashof number independently of the axial position for fully‐developed flow, and agreed with published data for pure free convection.
The effect of noise on process optimization
Authors: Heaps H. S. , Wells R. V.
Published: June 2009

The effect of noise on several methods of process optimisation is discussed. The optimising procedures include the gradient method, circle method, random search, and interpolation. Illustration is made with respect to two particular response surfaces in the presence of noise. The first surface is strongly unimodal; the second contains a sharp curved ridge which rises slowly to a single maximum. A technique is suggested for application to general unimodal response surfaces in the presence of noise.
Kinetics of gas‐solid non‐catalytic reaction
Authors: White Donald E. , Carberry James J.
Published: June 2009

Analytical relationships are derived for non‐catalytic first order diffusion influenced reaction between a gas and solid sphere of dimension which varies with extent of reaction. Bulk mass transport and diffusion through the product layer are assumed to occur in series with chemical reaction. The limiting case of totally volatile product is also treated. The fluid phase transport coefficient is incorporated as a general function of particle size and fluid velocity. The extent of reaction‐time relationship is more significantly affected by particle size change during reaction than by the functionality governing the bulk mass transport coefficient variation with geometry and velocity.
On corrective factors for project uncertainty
Authors: Rudd Dale F. , Watson Charles C.
Published: June 2009

A common method of accounting for uncertainty in an engineering project is to assign a minimum acceptable rate of return on capital investments. This minimum rate of return is assigned in a rather arbitrary way according to the expected risk in the project. In this paper we introduce the concepts of statistical decision theory and show how the minimum rate of return can be estimated in terms of uncertainty in sales income, project life, investment, manufacturing costs, etc.
Comparison of gas‐liquid contacting trays
Authors: Cej R. P. , Furter W. F.
Published: June 2009

The performances of four types of distillation tray of current industrial importance were compared in a common environment under similar hydraulic conditions. The four types investigated were the bubble‐cap, sieve, Turbogrid, and ripple trays. A single tray of each type, of representative dimensions, was used. The four trays were compared in regard to hydraulic characteristics, and also in regard to mass transfer efficiencies based on composition changes occurring in the gas phase during gas absorption. The comparison was carried out at relatively low vapor loadings in order to avoid excessive entrainment and channelling.
Heat transfer to agitated non‐newtonian fluids
Authors: Carreau Pierre , Charest Guy , Corneille Jean L.
Published: June 2009

Heat transmission to agitated non‐Newtonian liquids in a jacketed vessel has been studied. Heat transfer tests were conducted under unsteady‐state conditions with pseudo‐plastic solutions (behavior index range: 0.343 to 0.633).

For a generalized Reynolds number ranging from 100 to 5000, two correlations were found:

The use of a generalized Sieder and Tate number resulted in an equation combining both heating and cooling data with a somewhat higher mean deviation (19.3%):
Fluid friction and heat transfer in plain, concentric annuli
Authors: Ratkowsky D. A.
Published: June 2009

Each of the two friction factors in an annulus is defined in terms of the average kinetic energy of the fluid in the region between the radius of maximum velocity and the appropriate wall. These friction factors thus defined can be uniquely correlated against corresponding Reynolds numbers. The correlation is excellent for the outer portion of flow for all values of the radius ratio r1/r2, but not as good for the inner region of flow when r1/r2 is small. Applying the Colburn analogy, inner and outer wall j‐factors are similarly correlated with the same degree of accuracy.
The electrical conductivity of fluidized beds of coke and graphite up to 1200°
Authors: Graham W. , Harvey E. A.
Published: June 2009

Nitrogen‐fluidized beds of petroleum coke and graphite were heated by applying an a.c. voltage to electrodes submerged in the bed. Bed resistivities, calculated from the voltage and power input required to maintain a constant temperature, show a similar decrease in resistivity, for both materials, with increasing temperature up to 600°C., however, at about 600°C. the resistivity of graphite beds continues to decrease while that of coke beds goes through a minimum and then increases.

This was attributed to arc formation at the contacts between coke particles when the applied voltage exceeds a critical value. Similar behavior was not observed for graphite as the operating voltage never exceeded the critical value.
Thermal separation of coal‐oil suspensions in a fluidised bed
Authors: Round G. F. , Kruyer Jan , Hodgson G. W.
Published: June 2009

A series of experiments were made on the thermal separation of various mixtures of coal in oil using a fluidized bed reactor. The majority of experiments were carried out on a mixture of 30% w/w Edmonton coal in 70% w/w Leduc crude oil in a temperature range of 700–900°F. The products of the reaction were a char, an oil and a gas. At temperatures above 700°F. the solid particles became dry and free‐flowing; no agglomeration or channelling in the bed was apparent. An increase in reactor temperature in the 700–900°F. range decreased the amount of residual oil on the char from about 2% to 0.1% at the same time the heating value of the char rose from 11,900 to 12,600 Btu/lb. Carbon residue of the product oil was substantially less than that of the original oil, the reduction being about 50% in the case of Leduc oil and 75% for Lloydminster oil.
Correlation of pressure gradients for the stratified laminar‐turbulent pipeline flow of two immiscible liquids
Authors: Charles M. E. , Lilleleht L. V.
Published: June 2009

The parameters introduced by Lockhart and Martinelli to correlate pressure gradients accompanying the flow of gas‐liquid mixtures in horizontal pipes have been found to be useful in correlating data for the stratified flow of two immiscible liquids in the laminar‐turbulent regime. Curves through liquid‐liquid data available from three different sets of experiments, though being significantly displaced from the Lockhart‐Martinelli curves for gas‐liquid systems, represent the data with a maximum deviation of approximately 24%.
Experimental study of natural convective heat transfer in a non‐newtonian fluid: Part II. Horizontal plate
Authors: Reilly I. G. , Tien Chi , Adelman Maurice
Published: June 2009

Experimental data of natural convection heat transfer from a heated horizontal plate, both facing upward and downward, to a non‐Newtonian fluid are reported. Empirical expressions essentially similar to those developed for the vertical plate case are obtained which correrlate the data with reasonable accuracy.
The mixing of solid particles in a fluidized bed
Authors: Jinescu Gheorghitza , Teoreanu I. , Ruckenstein E.
Published: June 2009

In this paper a new experimental method, based on the freezing of the fluidized bed by the aid of paraffin wax is used for the determination of the diffusion coefficient of the solid particles. The experimental diffusion coefficients are compared with those given by a theoretical equation. In order to explain the time and spatial dependence of the experimental diffusion coefficient a cinematographic study supplemented by visual observations is also made. One concludes that for small tube diameters a circulation motion of the solid particles takes place which is responsible for the mentioned effect.
Surface diffusion in microporous media
Authors: Hwang Sun‐Tak , Kammermeyer Karl
Published: June 2009

The surface diffusion of He, Ne, H2, Ar, O2, N2 and CO2 through Vycor microporous glass was analyzed theoretically and experimentally in the low pressure range as a function of temperature. A statistical‐mechanical treatment was carried out in terms of partition functions to derive a general equation of surface flow. It was possible to separate the surface diffusion from the total flow using a simplified working equation. The conventional method which assumes that there is no adsorbed flow for helium should be discarded, because the fraction of surface diffusion for helium ranges from 0.133 to 0.247. It is also illustrated how to predict the permeability of a new gas for the same porous medium.
Particle trajectories and terminal velocities in vertically oscillating fluids
Authors: Houghton Gerald
Published: June 2009

The trajectories and terminal velocities of particles in vertically oscillating fluids have been studied by obtaining analytic and numerical solutions to the nonlinear Langevin equation representing a superposition of forces arising from particle acceleration, displaced fluid acceleration, buoyancy and particle‐fluid drag as represented by an nth‐power drag law. In vibrating fluids the directional particle velocities are found to be lower than in stationary fluids for drag exponents n > 1 and correspondingly higher for 0 < n < 1. The engineering significance of the results is discussed in relation to hold‐up, separation and transport phenomena in vertically oscillating multiparticle‐fluid systems.
Dynamics of a surface‐catalysed chemical system
Authors: Fahidy T. Z. , Perlmutter D. D.
Published: June 2009

The dynamic response of a periodically forced, surface catalyzed chemical system was studied experimentally. A comparison is made of dynamic correlations based on transfer function and equivalent gain models. The latter is shown to have significant advantages.
The expansion/contraction behavior of laminar liquid jets
Authors: Oliver D. R.
Published: June 2009

An apparatus for measuring the thrust of liquid jets is described and the effect of surface tension on jet thrust discussed in detail.

Whether the liquids used are nominally “Newtonian” or “viscoelastic”, there is a consistent trend in the expansion‐contraction behaviour. This is explained on the grounds that the fluids, from ethyl alcohol and glycerol on the one hand to poly (ethylene oxide) solutions on the other, possess appreciable elastic properties. Thrust measurements using short capillaries support this contention.

At very low Reynolds numbers the jet thrusts are unusually high; it is suggested that this results from a purelyviscous phenomenon.
The extrusion of silica and alumina powders: Part I. Extrusion
Authors: Griffith Richard M.
Published: June 2009

The extrusion of moist alumina and silica powders was experimentally studied. The materials were deduced to behave plastically by comparison with similar work on metals. Some factors required for coherent extrudate are considered.
Reduced state correlations of the enskog modulus for gases and liquids
Authors: Veeramani Hariharan , Thodos George
Published: June 2009

The Enskog modulus, bρ x, has been subjected to a generalized treatment to develop reduced state correlations for nonpolar and polar substances that exhibit hydrogen bonding. These correlations present relationships between 1 + bρx and ρR, the reduced density.

For nonpolar substances, the PVT data of argon, nitrogen, methane, ethane, and carbon dioxide were used for the development of these relationships, which were found to depend on zc, the critical compressibility factor. PVT data for ammonia, methyl alcohol, and water yielded a different correlation, which is applicable to polar substances which exhibit hydrogen bonding. These relationships were found to depend on the parameter, β = (Tb‐Tm)/M, which quantitatively describes the extent of hydrogen bonding for polar compounds.
The flow of suspensions through tubes: V. Inertial effects
Authors: Karnis A. , Goldsmith H. L. , Mason S. G.
Published: June 2009

The behavior of particles undergoing Couette and Poiseuille flows at rates when inertial effects become significant was investigated.

The rotation of rigid particles was similar to that in the Stokes flow regime, except for a drift of cylinders to limiting rotational orbits corresponding to the maximum energy dissipation.

In Poiseuille flow, rigid particles migrated to an equilibrium radial position which depended on the density difference of two phases, the directions of sedimentation velocity and flow, and the ratio of particle to tube radius. Neutrally buoyant deformable particles always migrated to the tube axis.

In concentrated suspensions a plasmatic layer developed near the tube wall as a consequence of radial migration. The formation of this layer modified the velocity profile and caused a reduction in the apparent viscosity coefficient.
Mass transfer from bubbles in cocurrent flow
Authors: Lamont J. C. , Scott D. S.
Published: June 2009

An experimental study has been made of liquid phase mass transfer from bubbles travelling cocurrently with liquid in a horizontal pipe. A simple model of the process based on streams of spherical bubbles has been developed and solved in the form of fractional absorption as a function of dimensionless groups. The derivation of and results obtained from this model are presented and explained. Experimental absorption rates measured in turbulent liquid flow over very wide ranges of bubble frequencies support the predictions of this model.

A very effective bubble‐frequency counter has also been developed capable of counts as high as 1600/min.
The characteristic dimension in scraped surface heat transfer
Authors: Bott T. R. , Romero J. J. B.
Published: June 2009

Previous published work on scraped surface falling film heat exchangers has used the tube diameter as the characteristic dimension. The present investigation confirms that in such equipment the liquid is carried as a fillet, roughly triangular in shape in front of the blades. Using an equivalent diameter based on flow area of the fillet and the length of the are in contact with the transfer surface, a correlation based on earlier results is developed which is independent of tube diameter, except in defining the rotary inertia forces. The refined correlation is:—
An evaluation of the pneumatic transport reactor
Authors: Yannopoulos J. C. , Themelis N. J. , Gavvin W. H.
Published: June 2009

In a pneumatic transport reactor, a dilute suspension of the reacting solid particles is conveyed by the gas stream through the reactor. The system is characterized by very short particle residence times. The relative flow rates of gas and solids are determined by the thermodynamic and kinetic requirements of the reacting conveyed systems.

Design considerations for co‐current gas and solids flows are presented and a comparison between co‐gravity and counter‐gravity flow reactors is discussed for the case of iron ore reduction by hydrogen. Kinetic data from single particle studies have been used to predict the performance of a pilot‐scale reactor.
A simulation and parametric study of four existing multi‐component distillation columns
Authors: Petryschuk W. F. , Johnson A. I.
Published: June 2009

The Θ‐method and block‐relaxation method of solving The non‐linear set of algebraic equations which describe the leady‐state behavior of standard distillation columns are compared.

The results from the mathematical models are compared with actual plant performance of a depropanizer, debutanizer, de‐ethanizer, and ethane‐ethylene splitter. Column section efficiencies are tabulated. A parametric study of the variation of feed condition, reflux condition and flow, and feed tray location was made on these columns and the responses of the key component concentrations have been mapped.

Such a study permits improvement of current plant operation. Its use for design of more efficient columns and arranangements is indicated.
Analytical solutions to the semi‐discrete form of the conduction equation for non‐homogeneous media
Authors: Darsi C. R. , Quon D.
Published: June 2009

The partial differential equation describing transient conduction (or diffusion) in non‐homogeneous media may be approximated by a set of first order linear ordinary differential equations if the derivatives involving the space variables are replaced by finite difference expressions. A general method of obtaining a closed form solution of these equations is presented, using some operational methods of linear algebra. The solution is given in terms of a matrix, which describes the spatial distribution of physical properties in the media, and vectors describing the initial and boundary conditions.
Momentum and heat transfer characteristics of liquid‐liquid dispersions in turbulent flow
Authors: Legan R. W. , Knudsen J. G.
Published: June 2009

The momentum and heat transfer characteristics of unstable, liquid‐liquid dispersions flowing turbulently in a circular tube were investigated. Two mineral oils, a light oil with viscosity of 15 centipoise, and a heavy oil with viscosity of 200 centipoise were used as the dispersed phase while the continuous phase was tap water. At room temperature only, the relative fluidity of the dispersion follows the relation

At Reynolds numbers above 60,000 the heat transfer coefficients of all dispersions studied follow the relation

where the Prandtl number is that of the continuous phase and the Reynolds number is based upon the viscosity of the dispersion. All properties are evaluated at the film temperature.
Some observations on heat transfer to agitated liquids
Authors: Appleton W. T. , Brennan W. C.
Published: June 2009

Heat transfer coefficients for agitated liquids in a flat‐bottomed vessel equipped with a heating coil have been measured over wide ranges of Prandtl and Reynolds numbers in order to examine the effect of coil surface, impeller design and coil geometry. The study of impellers included a comparison of flat‐bladed and pitched‐bladed agitators. Helical and baffle coil geometries were tested using smooth, knurled and finned tube surfaces. For all systems studied the Reynolds number exponent was observed to be dependent on viscosity. The data for finned tubes indicated higher transfer rates due to increased surface area and wall‐turbulence.
Optimal continuous fermentation reactor design
Authors: Bischoff Kenneth B.
Published: June 2009

Many optimum reactor combination schemes have been proposed for fermentation (autocatalytic) reaction systems. Usually these consist of series of stirred tanks or plug flow vessels. The basis for choosing an optimal scheme is here presented and it is found that for many cases of interest the combination of stirred tank ‐ plug flow is the best.
Discrimination between two rival models through nonintrinsic parameters
Authors: Mezaki R. , Kittrell J. R.
Published: June 2009

In analyzing data from heterogeneous reactions, it is often necessary to quantitatively compare the relative ability of two rival models to fit the data. For Hougen‐Watson models, techniques exist for comparing this degree of fit for low conversion data; a method is suggested here for making quantitative comparisons using high as well as the low conversion data. Once estimates of the parameters in the two models are obtained, the method may be applied by a one‐variable regression analysis. An example is presented illustrating the advantages of using all the conversion data in discriminating between two rival models.
Heat transfer limitations on nuclear reactor fuel elements
Authors: Rogers J. T.
Published: June 2009

Limitations on heat transfer rates on fuel elements in Canadian heavy‐water‐moderated reactors are examined.

With organic coolant in simple flow geometries, heat fluxes are limited by departure from nucleate boiling, (DNB); in simulated fuel bundles the failure mechanism can be either localized DNB, or coke‐out, the formation, deposition and rapid growth of coolant decomposition products on heated surfaces.

With boiling light water coolant, critical heat flux (CHF) is caused by DNB at low qualities and by dry‐out at higher qualities. Parameters governing CHF in tubes and annuli are fairly well established. Data for fuel bundles are becoming available. Methods of increasing CHF and of rationally setting margins of safety on CHF are being developed.
The determination of mass transfer coefficients and interfacial areas in gas‐liquid contacting systems
Authors: Dillon G. B. , Harris I. J.
Published: June 2009

Experimental studies of absorption without and with reaction in a single orifice bubble contactor and on a sieve plate have been used as the basis of interfacial area determinations. Results obtained were compared with values obtained by other techniques. The limitations of the method are discussed.
Adiabatic homogeneous bubbly flow in horizontal pipes
Authors: Hvey C. T.
Published: June 2009

The usual one dimensional method of analysis based upon the equations of continuity, energy and momentum is applied to the flow of homogeneous bubbly liquid‐gas mixtures in horizontal pipes. The analysis results in a set of equations which are adequate insofar as they are able ro explain known phenomena of the flow. It is shown that the concept of the Mach number, applied to bubbly pipe flow, is physically meaningful in the same way as it is in gas dynamics and that the condition, Mach number equal to one represents a realistic criterion for flow choking. A friction‐length formula is derived and verified experimentally.
Surface adsorption and the effect of column diameter in the continuous foam separation process
Authors: Wood R. K. , Tran T.
Published: June 2009

Foam separation has been investigated as a technique for removing ethylhexadecyldimethylammonium bromide, a cationic surfactant, from dilute solutions. An ideal foam model has been used to determine the surface excess accumulated at the solution‐air interface and to predict the foam and drain concentration in a continuous foam separation process. It was found that the model was valid only under conditions of good drainage and perfect foam stability.

An increase in column diameter for a feed of constant composition and supplied at a constant rate increased the concentration of the surfactant in the overhead stream. This highly desirable effect was accompanied by an increase in the drain rate. The results indicate that an increase in column diameter had an entirely beneficial effect on the efficiency of the separation.
Heat transfer studies in a climbing film evaporator Part II: Heat transfer regions
Authors: Gupta A. S. , Holland F. A.
Published: June 2009

There are three sections in an evaporator tube; liquid heating, foam and climbing film. A technique is presented for estimating the lengths of these three sections and the overall heat transfer coefficients in each of them.

The lower the liquid feed temperature, the longer the liquid heating length. The length of the foam section does not depend on the liquid feed temperature. In these studies it was estimated to be more than half the length of the evaporator tube. Only at the higher liquid feed temperatures was a climbing film found to exist.
Contrǒle anticipé de la température au moyen d'une calculatrice analogique
Authors: Cloutier L. , Girard J.
Published: June 2009

Un montage spécial a servi à l'étude du contrǒle de la température, dans un réservoir, par action anticipée. On a utilisé la température de l'alimentation au réservoir pour actionner le contrǒleur. Une vérification de la température à la sortie du réservoir avait pour but d'obvier au fait que des demandes imprévues pouvaient survenir au‐delà du point de contrǒle à l'entrée.

Les résultats obtenus indiquent que le contrǒle par action anticipée avec vérification à la sortie représente une certaine amélioration sur le contrǒle en boucle fermée. Une telle amélioration serait supérieure si les constantes de temps du procédé et de l'élément final de contrǒle étaient du měme ordre de grandeur.
Preparation of urania and urania‐zirconia microspheres by a sol‐gel process
Authors: Haas P. A. , Clinton S. D. , Kleinsteuber A. T.
Published: June 2009

The sol‐gel process was originally developed and applied at the Oak Ridge National Laboratory for preparation of high‐density thoria‐urania fragments and microspheres for nuclear reactor fuels. The application of the process for preparation of microspheres to sols of urania, urania‐zirconia, and urania‐carbon is reported in this paper. Relatively high‐strength, spherical particles of UO2, UO2‐ZrO2, and UC2 were prepared with diameters of 50‐500 microns and densities of 80‐100% of the theoretical densities.
Reactions of Amines with Zwitterionic Quinoneimines: Synthesis of New Anionic and Zwitterionic Quinonoids
Authors: Tamboura Farba B. , Cazin Catherine S. J. , Pattacini Roberto , Braunstein Pierre
Published: June 2009

Following the discovery of an unprecedented transamination reaction between primary alkylamines and a quinonoid molecule of the type [C6H2([pb2]NHCH2R)2([pb2]O)2] (1), obtained from commercially available diaminoresorcinol·2HCl, we have extended this method to the use of primary arylamines, and found that, in contrast, secondary amines led to a different outcome. Whereas functionalized molecules of type 1, which are best described as 6π + 6π zwitterions, were obtained with aniline or 4‐methoxyaniline, no transmination was observed with tBuNH2 in ethanol. In water, however, a reaction took place, but it afforded instead salt 6a, which resulted from hydrolysis of the imine group and deprotonation. Under similar conditions, secondary amines led to comparable results. The cations associated with the anionic quinonoid are readily exchanged in the presence of a primary amine. Whereas for the transamination reaction basic amines react under mild conditions, slightly harsher conditions are needed for less basic amines such as piperidine, diisopropylamine, or diethylamine. Transamination reactions were also performed with bis(methylamino) quinoneimine 4c, which is more soluble in organic solvents than 3. This led to the first examples of quinonoidal zwitterions functionalized with different alkyl groups on the nitrogen atoms. A number of compounds were characterized by X‐ray diffraction, which allowed a better understanding of their electronic situation, and in many cases, the presence of multiple hydrogen‐bond donors and acceptors results in crystal packings dominated by these interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Karplus‐Type Dependence of Vicinal 119Sn‐13C and 119Sn‐1H Spin‐Spin Couplings in Organotin(IV) Derivatives: A DFT Study
Authors: Casella Girolamo , Ferrante Francesco , Saielli Giacomo
Published: June 2009

The empirical Karplus‐type dependence of 3J(119Sn,13C) and 3J(119Sn,1H) couplings in organotin(IV) derivatives has been computationally validated by DFT methods both at the non‐relativistic and scalar ZORA relativistic level. A preliminary calibration of the computational protocols, by comparing experimental and calculated couplings for a set of suitable rigid molecules, revealed their high predictive power: in particular, relativistic results for 3J(119Sn,13C) have a mean absolute error of just above 2 Hz, over a range of values up to about 70 Hz. The latter protocol has then been used to study in detail the influence of substituents and multiple paths connecting the coupled nuclei on the vicinal coupling constants. Some conformational issues have been also considered. Significant effects have been observed and theoretical Karplus‐type curves for some representative systems have been proposed and discussed. It appears that general equations for vicinal 119Sn‐1H and 119Sn‐13C couplings cannot be derived, although the shape of the curves is preserved with |3J(0°)| < |3J(180°)| and 3J(90°) ≈ 0 Hz.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Binaphthalene‐Derived Iminium Salt Catalysts for Highly Enantioselective Asymmetric Epoxidation
Authors: Page Philip C. Bulman , Buckley Benjamin R. , Farah Mohamed M. , Blacker A. John
Published: June 2009

Enantiomerically enriched epoxides are useful intermediates that have found many applications in asymmetric synthesis, and development of efficient catalysts for asymmetric epoxidation has received considerable attention. In this manuscript we describe the design, preparation, and use of new highly selective iminium salt organocatalysts for asymmetric epoxidation, based around a chiral binaphthalene motif coupled with a chiral substituted dioxane moiety. The new catalysts have been tested in the catalytic asymmetric epoxidation of unfunctionalized alkenes, and provide up to 95 % ee. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Chemoenzymatic Synthesis of (Protected) Psymberic Acid
Authors: Pietruszka Jörg , Simon Robert Christian
Published: June 2009

Two alternative approaches to the side‐chain of psymberin (1), psymberic acid (5), have been developed starting from either racemic or enantiopure acetal 6. A five‐step chemoenzymatic route provided the PMB‐protected acid (S,S)‐16 required for the coupling that should ultimately lead to the natural product 1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Diversity in the person, diversity in the group: Challenges of identity complexity for social perception and social interaction
Authors: Bodenhausen Galen V.
Published: June 2009

Social psychological research is increasingly coming to grips with the complexity of social identity within the individual, both from the perspective of perceivers trying to form impressions and make judgments about multiply categorizable targets, as well as from the perspective of actors using their different self‐aspects as a framework for guiding their interactions with the social world. I review several contributions to the effort to better understand these issues and then explore some of their possible implications for understanding the nature and consequences of diversity within the group. Copyright © 2009 John Wiley & Sons, Ltd.
Renewable Ceramic (TiN) Ring Electrode in Stripping Voltammetry. Determination of Pb(II) Without Removal of Oxygen
Authors: Baś B. , Piech R. , Ziemnicka M. , Reczyński W. , Robótka M.
Published: June 2009

Characteristic features of the process of Pb(II) reduction and oxidation at a renewable ceramic ring electrode (RCRE) were studied by stripping voltammetry. The main constituents of the RCRE are: a specially constructed TiN ring electrode, a silver sheet used as silver counter/quasi‐reference electrode and a silicon O‐ring are fastened together in a polypropylene body. The renovation of this electrode is carried out through mechanical removal of solid contaminants and electrochemical activation in the electrolyte which fills the RCRE body. The optimal measurement conditions, composition of supporting electrolyte and procedures of the electrode activation were selected. The measurements were carried out from nondeaerated solutions. As shown on selected examples, RCRE exhibits good performance in underpotential deposition stripping voltammetry (UPD‐SV) applied for the determination of lead(II) in synthetic solutions with and without surfactants and in certified reference materials. The peak current is proportional to the concentration of lead(II) over the range 2×10−9–1×10−7 mol L−1, with a 3σ detection limit of 1×10−9 mol L−1 with an accumulation time of 30 s. The obtained results showed good reproducibility, (RSD=2–5%; n=5) and reliability.
Redox Couple of DNA on Multiwalled Carbon Nanotube Modified Electrode
Authors: Luo Hongxia , Li Shana , Guo Zhi‐Xin , He Nan , Dai Liming
Published: June 2009

It has been envisioned that carbon nanotubes could promote electron‐transfer reactions when used as electrode materials in electrochemical cells. In the present study, calf thymus DNA was electrochemically oxidized at an electrode modified with multiwalled carbon nanotubes. The potentials for DNA oxidation at pH 7.0 were found to be 0.71 and 0.81 V versus SCE, corresponding to the oxidation of guanine and adenine residues, respectively. An initial oxidation of adenine was observed in the first scan, which was followed by a quasi‐reversible redox process of the oxidation product in the subsequent scans.