bluuebunny/crossref_metadata_2025 huggingface dataset:
A filtration method for measuring particle interactions in latexes
Authors: Homola A. M. , Robertson A. A.
Published: March 2009

The repulsion forces between latex particles determine the stability of the latex. These may be estimated by determining, by a filtration method, the minimum pressure required to initiate coagulation. This minimum filtration pressure, when corrected for the resistance of the filter, was found to be independent of the pore size of the filter and of the amount and concentration of the latex. Experiments were conducted with both film‐forming (styrene‐butadiene) and non‐film forming (styrene) latexes.

The method provides a simple and convenient means of assessing the colloid stability of suspensions of larger particles. With model, monodisperse latexes the method permits the comparison of measured interparticle forces with those predicted by theory. The minimum coagulation pressure and the electrophoretic mobility curves correlate well when plotted against pH or electrolyte concentration. A maximum in the minimum coagulation pressure curve occurs at 10−3 M NaCl. The critical pressure increases with an increase in the concentration of nonionic surfactant (C18E50) while the mobility decreases.
Viscous dissipation effects on turbulent heat transfer in pipes with uniform wall heat flux
Authors: Ou Jenn‐Wuu , Cheng K. C.
Published: March 2009

An analysis is made of the turbulent Graetz problem with viscous energy dissipation effects in pipes with uniform wall beat flux. The effects of viscous dissipation on fully developed Nusselt numbers are studied for fluids with Prandtl numbers 1, 10, 102, 103 for Reynolds numbers between 5 × 103 and 5 × 105 with both cooling and heating conditions at the pipe wall. The viscous dissipation effects on convective turbulent heat transfer in arctic hot oil pipelines are discussed.
The dispersed flow model for a biological reactor as applied to the activated sludge process
Authors: Turian Raffi M. , Fox George E. , Rice Philip A.
Published: March 2009

A theoretical analysis of a dispersed flow biological reactor is presented in which Monod growth kinetics are used to describe the substrate utilization rate and the bacterial growth rate. Different bacterial and substrate dispersion coefficients are taken into account. Approximate perturbation solutions are established for two limiting situations, when the inverse Peclet number ϵ is very small and when it is very large. In the former case the perturbation analysis is singular. These perturbation solutions are compared with the solutions of the numerically integrated equations over a range of parameters corresponding to actual activated sludge systems. The application to the activated sludge system is discussed.
Mass transfer in venturi scrubbers
Authors: Virkar P. D. , Sharma M. M.
Published: March 2009

The theory of gas absorption with chemical reaction was used to obtain values of effective interfacial area, a, liquid‐side mass‐transfer coefficient, kLa, and gas‐side mass transfer coefficient, kGa, in a venturi scrubber for the Wet‐Approach mode of operation. Some data were also obtained for the Pease‐Anthony mode of operation in order to make a rational comparison between the two modes of operation. The hydrodynamic characteristics of the venturi scrubber were studied for the two modes of operation over a wide range of gas and liquid flow rates. Further, the effect of the viscosity of the liquid and the surface tension on effective interfacial area was investigated.
A model for the formation of calcium carbide in solid pellets
Authors: Brookes C. , Gall C. E. , Hudgins R. R.
Published: March 2009

Experiments have been conducted on the formation of calcium carbide in the solid state from 2.22‐cm diameter cylindrical pellets of a 3/1 mole mixture of carbon and lime between 1650°C and 1720°C at 50 mm Hg CO pressure.

The reaction was modelled assuming that heat transfer across a growing product layer controls the rate of movement of a reaction front where the overall reaction to form CaC2 is assumed to occur instantaneously to a fractional conversion f. The model depends upon a knowledge of the CaC2 decomposition rate in the product layer ko2e−ΔE/RgT and the effective thermal conductivity k0. These may be estimated from independent data but require adjustment for particular pellet conditions. Good agreement with the data shows that the model is adequate for preliminary design and optimization studies.
Semi‐empirical formulae for the prediction of diffusion in liquid systems
Authors: Simons J. , Ponter A. B.
Published: March 2009

A critical survey of the published theoretical and experimental approaches to diffusion in liquids is presented. A study of the effects of temperature and viscosity demonstrates that the Stokes — Einstein equation and other relations derived from the hydrodynamic theory can only be applied in special cases. Correlations based on Eyring's absolute rate theory are shown to predict diffusivities more accurately in most cases at the expense of additional complications some of which are shown to be unnecessary.
Induced liquid phase mixing due to bubble motion at low gas velocity
Authors: Subramanian Gopal , Tien Chi
Published: March 2009

Liquid phase mixing induced by gas bubbles at low gas velocities was studied experimentally. An experimental technique based on the principle of spectrophotometry was developed and applied in the experimental work. Experimental evidence suggests that the mixing phenomenon can be described as a diffusive process characterized by an effective diffusivity which is found to be a linear function of superficial gas velocity.
Flow analysis and end corrections in falling coaxial cylinder viscometry
Authors: Chee K. K. , Rudin Alfred
Published: March 2009

The assumptions involved in the analysis of flow of polymer melts in a closed end falling coaxial cylinder viscometer(1–3) are examined and it is shown that true values of shear rate and shear stress at the wall of the moving cylinder can be obtained by assuming classical Poiseuille flow. Flow curves obtained with a variety of apparatus geometries, driving loads and polymers are consistent with those of other measurement techniques. This apparatus, which is a simple modification of a capillary extrusion rheometer, provides measurements of apparent viscosity at much lower shear rates than can be obtained with the former viscometers.

A quantitative measurement of end correction effects is provided by the present analysis. End effects, which are formally similar to those in capillary extrusion, were measured for several polystyrenes and polyethylenes.
Mixing of viscoelastic fluids with helical‐ribbon agitators. I — Mixing time and flow patterns
Authors: Carreau P. J. , Patterson I. , Yap C. Y.
Published: March 2009

Batch mixing of viscous fluids with helical‐ribbon agitators in 2.4 liter and 13 liter vessels has been studied for agitator speeds up to 200 RPM. Seven different agitators of different dimensions were employed in this work. Mixing times were measured using a decoloration technique and circulation times were determined by the tracer bead method. In addition, velocity profiles were obtained from streak photographs using selective illumination of the vessel and PVC powder as tracer particles.

It was found that the mixing times of Newtonian fluids, which agreed with previously published data, were considerably (3 to 7 times) shorter than those of the viscoelastic fluids. The mixing time was strongly affected by the fluids' elasticity; increasing as the fluid elasticity increased. The velocity profiles were qualitatively similar for all the fluids but showed decreased axial circulation and increased circumferential flow as fluid elasticity increased. However, mixing is not only a function of the axial circulation (impeller pumping rate) but also is a function of the perturbations superimposed on the main flow. A simple, first approximation model based on the impeller geometry and flow patterns is proposed to correlate the circulation capacity and mixing time data for the various geometries studied.
A least squares approach to model reduction and the design of low‐order controllers
Authors: Wilson Robert G. , Seborg Dale E. , Fisher D. Grant
Published: March 2009

State space process models and feedback control laws are simplified by eliminating selected state variables using a modified least squares technique. The revised technique uses random perturbations to excite the high order system and the resulting reduced‐order models tend to be more robust than those derived using conventional least squares and deterministic inputs. Low‐order controllers were designed for a pilot scale, double effect evaporator using the modified least squares approach. These controllers performed well in both experimental and simulated response tests.
The flow of sand/water slurries in horizontal pipes with internal spiral ribs — effect of rib height
Authors: Singh V. P. , Charles M. E.
Published: March 2009

The effect of secondary flows created by an internal spiral rib in an otherwise conventional smooth 2‐inch pipe on the transportability of “settling” suspensions of sand in water was investigated with emphasis on the effect of rib height.

While the ribs were found to be a disadvantage at relatively high average mixture velocities because of increased pressure gradients, they were advantageous at low velocities. The deposit velocity and the pressure gradient at the deposit velocity in ribbed pipes of several pitch to diameter ratios and rib heights were correlated with respect to the corresponding smooth pipe values. These correlations are useful in pipeline design. The optimum rib geometry was estimated to be a pitch to diameter ratio of about 8 and a rib height in the range of 10–15% of the pipe diameter for the solid‐liquid mixtures investigated.
Wall mass transfer in vertical and horizontal slurry pipelines
Authors: Postlethwaite John , Holdner D. N.
Published: March 2009

Wall mass transfer rates of dissolved oxygen have been measured in a vertical pipe, 5 cm. I.D., carrying aqueous slurries of 5, 10, and 15 vol%, 60–100 and 30–50 mesh sands at velocities in the range 1.2 to 3.35 m/s. The results show increases of up to 100% over those found with water, with the effect of the solids increasing with decreasing particle size and increasing with increasing concentration. The jD factors decreased linearly with increasing Res, unlike the previous results with horizontal pipes where maxima were found relating to vertical concentration gradients.
The effect of temperature on coalescence of liquid drops at liquid/liquid interfaces
Authors: Vijayan S. , Furrer M. , Ponter A. B.
Published: March 2009

Drop/interface coalescence times measured at 293–343K are reported for three oil/water systems (benzene, paraffin oil and 1,1,2,2‐tetrabromoethane) with different interface ages. The anomalous coalescence behavior of water droplets is explained by considering the static electrical double‐layer residing at the interface which influences the film thinning and the film rupture processes.

Analyses using simplified coalescence models reveal that the incorporation of temperature dependence on the physical properties such as density difference between phases, viscosity of the continuous medium and interfacial tension, does not produce satisfactory agreement with the measured coalescence times.

The effect of mutual saturation in contrast to unsaturated systems on coalescence times is illustrated. The reproducibility of the drop/interface coalescence times is examined and explanations are offered, relating the method and the conditions of the experimentation.

Finally the importance of both the coalescence time and the film thickness to drop stability analysis is demonstrated.
Characterization of the evaporation rates of complex hydrocarbon mixtures under environmental conditions
Authors: Goodwin S. R. , Mackay D. , Shiu W. Y.
Published: March 2009

The characterization of the evaporation rate of complex hydrocarbon mixtures, such as commercial oil fractions, under environmental conditions is discussed. It is shown that the relevant thermodynamic quantity is the total volume of vapour (per unit of initial oil mass) removed under isothermal differential distillation conditions (V m3/kg) as a function of the mass fraction of the oil remaining (F). Plots of F versus V for various isothermal conditions can be used to estimate evaporation rates since it is shown that V is equivalent to the group KsAsτs/Ms where Ks is the evaporation mass transfer coefficient (m/s), As is the spill area (m2), τs is the evaporation time (s) and Ms is the spill mass (kg). The basis of a methodology for estimating environmental evaporation rates is thus outlined. Methods of obtaining V versus F data are discussed, with calibrated wind tunnel evaporations being preferred. The estimation of evaporation rates under spreading and non‐isothermal conditions and the analogous dissolution process are discussed briefly.
Holographic determination of mass transfer due to impinging square jet
Authors: Masliyah Jacob H. , Nguyen Trung T.
Published: March 2009

Local mass transfer from a flat plate under the influence of an impinging laminar air jet, issuing from a square tube, has been studied using laser holographic interferometry. No angular variation in mass transfer was found to exist near the jet centre. However, in regions far from the jet centre a periodic angular variation in mass transfer was shown to exist. Regression equations for the local mass transfer coefficient are presented for Re = 710, 980, 1325 and 1810.
The electroreduction of oxygen to hydrogen peroxide on fixed bed cathodes
Authors: Oloman C. , Watkinson A. P.
Published: March 2009

The production of dilute alkaline peroxide bleaching solutions by electro‐reduction of oxygen on fixed beds of graphite particles was investigated. The cell was operated both in the two‐phase mode where oxygen saturated 0.1 M NaOH was passed continuously through the bed, and in the three‐phase mode where oxygen gas and electrolyte flowed co‐currently downward through the cell. Experiments were carried out under oxygen pressures from 1 to 12 atmospheres. The peroxide concentration at the reactor outlet, and the current efficiency dependence on the applied current are reported as functions of electrolyte and oxygen flowrates, oxygen pressure, graphite particle size, fixed bed height and electrolyte pH. Conditions for producing maximum peroxide concentrations are described and possible rate limiting steps in the reaction suggested.
Droplet size distribution: An improved method for fitting experimental data
Authors: Lekic A. , Bajramovic R. , Ford J. D.
Published: March 2009

The problem of obtaining the best fit for experimentally determined droplet size distributions is critically examined. Previous analyses have been restricted to linear representations of droplet distribution information. By using a statistical distribution and least squares fitting for non‐linear systems, the least squares estimates for parameters are obtained. The upper limit function and Chi‐square distribution are found to give good approximations for drop size distribution. Very precise fits of experimental data from a number of authors are obtained, the normalized volume distribution being more precisely approximated than the normalized number distribution.
Modified parameters for the Redlich‐Kwong equation of state
Authors: Kato Masahiro , Chung W. K. , C.‐Y.Lu Benjamin
Published: March 2009

Two new parameters are proposed for the Redlich‐Kwong equation of state. They are developed for pure components at T>Tc with emphasis placed on the application of the Redlich‐Kwong equation to vapor‐liquid equilibrium studies.

The proposed parameters reflect the departure from the experimental Tc and Pc values, and are related to the conventional parameters. Calculated critical isotherms of pure propane and hydrogen by means of the proposed method and two methods available in the literature are compared and discussed.

A set of mixing rules is proposed for correlating vapor‐liquid equilibrium data. Critical volumes and acentric factors of pure components are not required in the application of these mixing rules.

Applicability of the proposed new parameters and mixing rules is demonstrated by the correlation of vapor‐liquid equilibrium data for five binary systems at thirty‐two isothermal conditions and by the prediction of the triple‐values dew‐point curve for the methane‐n‐butane mixtures.

Based on a paper presented at the Research Seminar on “Vapor‐Liquid Equilibria in Multicomponent Mixtures” November 2–6, 1975 at Jablonna, Poland.
Low peclet number heat transfer in the thermal entrance region of parallel‐plate channels with unequal wall temperatures
Authors: Wu Rayshing , Cheng K. C. , Ou Jenn‐Wuu
Published: March 2009

The problem of low‐Peclet‐number thermal entry heat transfer for plane Poiseuille flow in parallel‐plate channels with uniform but unequal wall temperatures is approached by the eigenfunction expansion method utilizing the Gram‐Schmidt orthonormalization procedure. The formulation considers axial heat conduction and allows upstream heat penetration through the thermal entrance. Numerical results are obtained for the case with entrance condition parameter θ0 = 1 and Peclet number Pe = 1, 5, 10 and 50. The effect of Peclet number on temperature distributions in both upstream and downstream regions is studied. At Pe = 50, the concept of thermal boundary layer is applicable and the present series solution does not yield physically reasonable temperature distribution locally near the upper plate at the thermal entrance. The difficulty may be attributed to the nature of thermal boundary conditions at the thermal entrance and the transition from elliptic problem to parabolic problem with the increase of Peclet number.
The thermodynamics of the hydrogenation of oxides of carbon
Authors: Anderson Robert B. , Lee Chung Boon , Machiels Joseph C.
Published: March 2009

The thermodynamics of the hydrogenation of CO and CO2 is summarized. Equilibrium compositions for a number of reactions proceeding simultaneously to yield a number of hydrocarbons and oxygenated organic molecules are reported. If methane is included in these calculations, methane is the predominant product; therefore, for the production of other molecules selective catalysts are required.

For producing methane the hydrogenation of CO2 rather than CO may be advantageous, because the reaction is less exothermic. Thermodynamic calculations and results of tests on Raney nickel in a small tubular reactor show that high yields of methane can be obtained in the hydrogenation of both CO and CO2 at temperatures as high as 450°C.
Optimization by catalyst packing in tubular reactors with catalyst decay
Authors: Gruyaert F. , Crowe C. M.
Published: March 2009

The optimal initial distribution of catalyst activity along the axis of a tubular fixed bed reactor is examined for a class of reaction‐deactivation problems. A general set of simultaneous reactions is considered and a quasi‐steady state approximation is used in describing the reaction kinetics. The rate of decay of the catalyst is expressed as a function of temperature, concentration or degree of conversion and catalyst activity. The influence of various initial catalyst activity distributions upon the reactor performance is studied theoretically for several types of decay rate expressions. Numerical results are presented for a single irreversible reaction with a conversion‐dependent decay rate.
Kinetics of hydrogen reduction of cobalt sulfide
Authors: Fahim M. A. , Ford J. D.
Published: March 2009

The hydrogen reduction of cobalt sulfide (Co9S8) at atmospheric pressure in the temperature range 600–800°C has been experimentally investigated. When sulfide pellets were used, the rate constants were overestimated. The true intrinsic kinetics of this reaction were obtained from another set of experiments using sulfide powder, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 600–737°C, the rate constant for the powder reaction could be expressed as:

Above 780°C, cobalt metal whiskers were formed, and this led to swelling and cracking of pellets.
Axial dispersion in a rectangular bubble column
Authors: Stiegel G. J. , Shah Y. T.
Published: March 2009

This paper presents the results of an experimental study on the gas holdup and the liquid phase axial dispersion coefficient in a narrow packed and unpacked rectangular bubble column. In both cases the gas and liquid flow rates were varied and the data were obtained by employing standard tracer technique. The gas holdup and the axial dispersion coefficient for both the packed and unpacked columns were found to be dependent on the gas and liquid flow rates. For given gas and liquid velocities and a given packing size in the case of the packed column, the rectangular column gave significantly higher dispersion coefficients than a cylindrical column of the equivalent cross sectional area. This result agrees very well with the one predicted by the velocity distribution model. The correlations for the Peclet number, the axial dispersion coefficient, and the fluid holdup for both the unpacked and packed bubble columns are presented.
Fluid flow and heat transfer in internally finned helical coils
Authors: Masliyah Jacob H. , Nandakumar K.
Published: March 2009

The equations of motion and energy for Newtonian fully developed fluid flow in an internally finned helical coil were solved numerically for the case of uniform heat flux with peripherally uniform temperature for low Reynolds numbers. Plots for the axial velocity, secondary stream function and fluid temperature are given. For a given fin geometry, it was found that fRe is both a function of Dean number and radius of curvature, whereas the average Nusselt number is a function of Dean number only. For a given fluid at a constant pressure drop, a finned coil gave lower values for the average Nusselt number than a finless tube with the same inside diameter and radius of curvature.
Flow boiling and pool boiling critical heat flux in water and ethylene glycol mixtures
Authors: Frea W. J. , Knapp R. , Taggart T. D.
Published: March 2009

Flow boiling and saturated pool trailing were studied in water, and in ethylene glycol and aqueous antifreeze solutions. Boiling took place from an electrically heated cast iron surface at pressures close to atmospheric. In the flow boiling tests, velocities and subcoolings were varied up to 3 m/s and 36°C respectively, and effects of changes in flow passage geometry were examined. In 50 weight percent antifreeze mixtures the pool boiling critical heat flux increased relative to pure ethylene glycol in aqueous solution. Both critical heat flux and heat transfer coefficients decreased as percent water in the mixtures tested was reduced.
Corrosion product transport in water‐cooled. nuclear reactors Part I: Pressurized water operation
Authors: Bvrrill K. A.
Published: March 2009

Corrosion of out‐core piping in the primary circuit of nuclear power reactors adds both dissolved and particulate metals and their oxides to the water coolant. The particles deposit on the fuel sheaths and pressure tubes in the reactor core and are irradiated there while they dissolve in the heated water. Transport of now‐radioactive solute around the circuit makes the out‐core surfaces radioactive, which increases radiation exposure to operators and maintainers.

A mathematical model has been developed to describe these processes of deposition, irradiation and release of corrosion products on the fuel bundles and pressure tubes of CANDU pressurized water reactors. The model's predictions compare well with data from in‐reactor loop fuel, and data from fuel and pressure tubes from Pickering Generating Station. The model suggests ways to control the growth of out‐core radiation fields and keep them at the current low levels of Pickering. Hot filtration of the reactor water and an increase in water pH are two solutions analyzed with the model.
Effect of turbulence on the precision of velocity and velocity fluctuation data obtained by photochromic visualization
Authors: Humphrey Joseph A. C.
Published: March 2009

Even though photochromic flow visualization has been applied to a large range of flow configurations, no analytical study has been made indicating the effects of turbulence fluctuations on the precision of velocity and turbulence data measured by means of the technique. Because of the quick break up and dispersion of photochromic traces by turbulent eddies in the flow it is useful to know a priori the number of observations from which velocity and turbulence data can be determined with a prefixed precision. The paper presents equations and figures from which this and other useful information may be derived.

low Reynolds number and by Seeley et al(5) in their
Direct contact condensation from air‐steam mixtures on a single droplet
Authors: Kvlic E. , Rhodes E.
Published: March 2009

A new model is derived (and the corresponding numerical algorithm developed) to describe the temperature field of a suddenly exposed droplet experiencing moisture condensation from air‐steam mixture. This model is then compared with the predictions of two simpler models.

Experiments done over a wide range of air‐steam concentrations, drop sizes and gas phase velocities show that the combined heat and mass transfer model incorporating partial internal mixing accurately predicts the temperature responses of the droplets.
A contactor for studying mass transfer with reaction in liquid‐liquid systems
Authors: Landau J. , Chin M.
Published: March 2009

A contactor has been developed which is especially suitable for experimental investigations of mass transfer with chemical reaction in liquid‐liquid systems. Its function has been tested with the reaction between tetrachlorohydroquinone (dissolved in a mixture of 2‐octanone and carbon tetrachloride) and ceric sulfate (in 0.5M sulfuric acid). In the contactor described in this work the kinetics of this reaction can be investigated in the very slow reaction regime (kinetic regime). It is also possible easily to determine whether a reaction takes place to an appreciable extent in only one or both phases.
Flow dynamics in distillation columns packed with dixon rings as used in isotope separation
Authors: Gilath CH. , Cohen H. , Wolf D.
Published: March 2009

Packed distillation columns are common in isotope separation. The pressure drop serves as an indication for the hydrodynamic state of the column. Models were formulated for flow and pressure drop dynamics in packed distillation columns. These models were confirmed on columns packed with Dixon rings and operated with water for separation of oxygen isotopes.

Liquid holdup displacement is very important in isotope separation practice. Experiments proved that distillation columns packed with Dixon rings exhibit a behaviour close to plug flow.
Carbonisation de la tourbe pour l'élimination d'ions métalliques en solution aqueuse
Authors: Therien N. , Boucher J. M. , Beerli M.
Published: March 2009

The use of natural peat moss as a cation exchanger is well known. This study considers the ionic exchange characteristics of the powdery material produced by carbonization of the peat.

Yields of carbonized peat on a basis of calcium ion exchange capacity have been obtained for different temperatures and times in a tubular fixed bed furnace. Results have indicated a crucial temperature zone for maximum exchange capacity.

A critical dependence of the capacity for metal ion removal on the solution to be treated has been demonstrated. Rates of removal have also been characterized. Exchange capacity isotherms were obtained for several metal ions and results for the regeneration of carbonized peat are also reported.
Viscosity of organic liquids at elevated temperatures and the corresponding vapour pressures
Authors: Medani M. S. , Hasan M. A.
Published: March 2009

This work involved the measurement of the viscosities of pure organic liquids at temperatures ranging from 353.15 K to 463.15 K and at the corresponding vapour pressures. A rolling ball viscometer was used where considerable emphasis was given to achieve simplicity and rapidity in obtaining results, without sacrificing the accuracy.

Considering the forces affecting the motion of the ball inside the viscometer tube, an equation for the calibration of the viscometer at the same working temperature was derived. The constants of this equation were determined using benzene as the reference liquid, and the dependency of the constants on the temperature was also established. Comparing the derived equation with published ones demonstrated its adequacy in both the streamline and transition flow conditions.

The liquids studied were toluene, methanol and n‐hexane. In some cases, the results compared reasonably well with published data while in others, deviations of up to 15% were found.

Nine equations were tested with the experimental results for the prediction of the viscosity of these liquids. It was found that the 3‐constant Agrawal and Thodos empirical equation gave the least average deviation.
The solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous dipa solution
Authors: Isaacs E. E. , Otto F. D. , Mather A. E.
Published: March 2009

The solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous solution of di‐isopropanolamine (2.5 kmol m−3 DIPA) has been measured at temperatures of 40 °C and 100°C. Partial pressures of CO2 ranged from 2.0 to 5991 kPa, while partial pressures of H2S ranged from 1.3 to 4126 kPa.
Estimation of thermo‐ and diffusiophoretic particle deposition
Authors: Whitmore P. J. , Meisen A.
Published: March 2009

Theories are developed for estimating thermo‐ and diffusiophoretic deposition of particles in liquid as well as gas phase heat and mass transfer equipment, operating under turbulent conditions. Simple expressions are obtained which give satisfactory agreement with experimental data. It is shown that the phoretic effects can lead to appreciable particle deposition, and the practical implications of this, such as heat exchanger fouling, are discussed. The simultaneous occurrence of these and other deposition mechanisms is also considered.
Séparation isotopique d'azote 15 par échange chimique: Influence de la composition des gaz de reflux dans le système NO (gaz.) — N2O3 (liq.)
Authors: Lacoste G. , Bes R. , Routie R.
Published: March 2009

A study has been made on the gaz phase composition effect on the isotopic separation of nitrogen 15 for the NO‐N2O3 system. It was shown that the changes in composition of the gas phase could account for the increases in the overall separation.
Fluid mechanics and resource development
Authors: Charles Michael E.
Published: March 2009

Novel fluid flow concepts have played important roles in the development of hydrocarbon and other resources. This has occurred frequently in such areas as mining and production, pipeline transportation and resource processing. Examples of interesting flow concepts drawn from experience with a wide variety of projects are discussed with the thought in mind that they may prove useful in the search for improved and new methods for the extraction of hydrocarbons from oil sands.
A theory for predicting the maximum spoutable height in a spouted bed
Authors: Littman Howard , Morgan Morris H. , Vuković D. V. , Zdanski F. K. , Grbavčić Ž.B.
Published: March 2009

A theory is presented for predicting the maximum spoutable height, in a spouted bed where fluidization of the annular solids limits the penetration of the fluid jet entering the bed.

The quantity (Hmds/(D – d) is found to be a function of ds/Dc only for spherical particles and

\[ \frac{{H_m d_S }} {{(D_c^2 ‐ d_S^2 )}} = 0.345\left( {\frac{{d_S }} {{D_c }}} \right)^{ ‐ 0.384} \]

where the spout diameter is calculated using McNab's correlation(7). Insertion of McNab's correlation into Equation (1) shows that Hm is proportional to D and the effect of dp on Hm varies from d to d as the particle Reynolds number increases assuming 1 ≥ (ds/D).

Using experimental value of ds, the calculated values of Hm differ from the experimental ones by 8.5% on average.

When small particles are spouted with air, the penetration of the jet is limited by the formation of a slug in he spout and the theoretical value provides an upper limit for Hm.
The oxidation of ortho‐xylene on vanadium pentoxide catalysts II. The influence of catalyst support material on product distribution
Authors: Wainwright M. S. , Hoffman T. W.
Published: March 2009

The oxidation of o‐xylene has been investigated on a number of commercial vanadia catalysts in an isothermal packed bed reactor. The data show that phthalic anhydride selectivities of up to 85 mol percent can be obtained on titania supported catalysts whereas maximum values of around 30 mol percent are achieved on silica supported catalysts.

An attempt at modelling the kinetics of the reactions using the Redox mechanism is reported. The results indicate that this model is not adequate to fully describe all reactions. Some of the difficulties are indicated and suggestions are made for modifications to the models along with directions for future work.
An exploratory study of the behaviour of crude oil spills under ice
Authors: Greene G. D. , Leinonen P. J. , Mackay D.
Published: March 2009

An experimental spill of 0.38 m3 of warm (55°C) crude oil under the ice cover of a fresh water pond with an underwater viewing port is described. Temperatures, dissolved hydrocarbon concentrations and oil slick behaviour and areas were determined. Some oil recovery and disposal methods were tested. An attempt has been made to quantify the rates of heat and mass transfer from the oil using reported values for transfer coefficients. The results indicate that the oil slick adopted a thickness of about 2 cm under the ice, that heat transfer from the oil was relatively fast and complete, that dissolution mass transfer is slow resulting in oil concentrations in the water of only 18 to 287 μg/l in the vicinity of the spill. Some recommendations are made for further studies to elucidate the nature and rates of the relevant physical processes and thus assist in assessing the environmental impact of under‐ice oil spills.
A generalized one‐parameter redlich‐kwong equation for vapor‐liquid equilibrium calculations
Authors: Kato Masahiro , Chung W. K. , Lu Benjamin C.‐Y.
Published: March 2009

The two modified parameters previously proposed for the Redlich‐Kwong (RK) equation of state are simplified and reduced to a one‐parameter model, and extended to vapor‐liquid equilibrium (VLE) calculations involving supercritical components. However, the original RK parameters are still treated as temperature‐ and substance‐dependent.

In this investigation, this parameter is generalized in terms of Tr and Ω. The values obtained from the generalized correlation are suitable for calculating VLE data at T ≤ Tc for all components, and at temperatures where some of the components are in the supercritical region.

The validity of the generalized correlation is supported by its ability to represent saturated properties of the pure components and to predict VLE data for five binary systems at 58 isothermal conditions, and one ternary system at two isothermal conditions.
A simple model to calculate the solubility of liquid water in compressed air
Authors: De Santis R. , Marrelli L.
Published: March 2009

A perturbed hard‐sphere equation of state is used to calculate the solubility of liquid water in compressed air at pressures up to 40 MPa.

The proposed model does not require the knowledge of ternary data and is generally applicable to the calculation of the solubility of polar or associating liquids in non polar gases.
Bulk and interfacial physical properties of aqueous solutions of sodium lauryl sulphate and lauryl alcohol with air and benzene system: Part I: Aqueous solutions of sodium lauryl sulphate
Authors: Vijayan S. , Woods Donald R. , Vaya Helene
Published: March 2009

Experimental measurements were made of the pH, density, bulk viscosity and electrical conductivity of aqueous solutions of sodium lauryl sulphate for a wide range of concentrations at 25°C. Also, the time‐dependent interfacial tension data of this system with mutually saturated benzene phases are reported. Comparison of these data with literature values shows fair agreement in the majority of the cases and further reveals the lack of data in the earlier investigations below the critical micelle concentration of sodium lauryl sulphate in water.

A detailed compilation of the data, reported in the literature since 1937, of the pH, density, bulk viscosity, electrical conductivity, surface tension, interfacial tension with benzene, surface excess concentration, surface shear viscosity, diffusivity and critical micelle concentration of the sodium lauryl sulphate system is given. The importance of this anionic surfactant system together with the various factors which influence the physical properties is examined.
Motion of liquid drops in rheologically complex fluids
Authors: Acharya A. , Mashelkar R. A. , Ulbrecht J.
Published: March 2009

The influence of viscoelasticity and of the shear‐dependent viscosity of ambient liquids on the motion of liquid drops was examined experimentally. In the low Reynolds number region (Re < 1) the influence of elasticity is insignificant and the influence of the variable viscosity is well accounted for by the existing correlations. At higher Reynolds number (Re > 1) the viscoelasticity brings about a substantial increase of drag. An interpretation of this phenomenon is attempted in view of the changes of the wake behind the drop and an empirical correlation in terms of the Weissenberg number is suggested. Additionally it was found that the “wave theory” as presented by Marrucci et al(8) can be satisfactorily used for drops moving at Re > 10 irrespective of rheological complexities.
Conditions minimales de mise en fluidisation par un liquide
Authors: Riba J. P. , Routie R. , Couderc J. P.
Published: March 2009

La vitesse minimum de mise en fluidisation d'une charge de particules sphériques par un liquide est relié aux variables caractéristiques du système par la relation:

Cette corrélation, contrairement à celles rencontrées dans la biblographie, ne fait pas intervenir le degré de vide de la couche au seuil de fluidisation.
Effective interfacial area in packed beds for absorption with chemical reaction
Authors: Patwardhan V. S.
Published: March 2009

The extended crossflow model is proposed and developed for describing gas absorption with chemical reaction in a packed bed operated in the trickle flow regime. The model involves the division of the total interfacial area into the interfacial area of the static hold‐up and that of the dynamic hold‐up. The concept of the effectiveness of the interfacial area of the static hold‐up is presented. A procedure is developed for calculating the effectiveness, and consequently, the effective interfacial area for various different absorption processes with chemical reaction, both liquid phase controlled and gas phase controlled. The predictions based on the present model agree well with reported experimental data. The present model is shown to be simpler and more accurate than previous models.
Corrosion product transport in water‐cooled nuclear reactors: Part II: Boiling water with direct cycle operation
Authors: Burrill K. A.
Published: March 2009

Corrosion product transport in a water‐cooled nuclear reactor causes gamma‐radiation fields to grow around the heat transport circuit. An hypothesis is given which identifies some of the mechanisms causing radiation field growth in a CANDU direct‐cycle, boiling water reactor. Overall, predictions from a mathematical model of the hypothesis agree well with data. Comparisons are made for deposit weights of iron on fuel sheaths and for radionuclide specific activities in deposits on the fuel sheaths of the CANDU prototype direct‐cycle, boiling water reactor at Gentilly, Quebec. As well, radionuclide specific activities measured in particles in the water, and in deposits in the steam drums are compared with the model. Filtration of corrosion products from the reactor feedwater is suggested as one way to control radiation field growth.
Numerical calculation of developing laminar flow in pipes of arbitrary curvature radius
Authors: Humphrey Joseph A. C.
Published: March 2009

Elliptic forms of the Navier‐Stokes equations in rigorously formulated toroidal coordinates are solved numerically for laminar, incompressible, isothermal flow in curved pipes of small curvature radius and 90° deflection angle. As a special case, the flow through curved annuli is also considered in which the presence of the inner curved wall causes the appearance of two (rather than one) pair of cross‐stream vortices. Recirculation in the main flow direction is observed at the outer curvature wall of a pipe with Rc/d = 1 and Re = 1800 over a deflection angle corresponding to 9° ≤ θ ≤ 21°. Flow reversal is attributed to the large and unfavorable longitudinal pressure gradient prevailing at the outer curvature wall over the first half of the pipe. Calculations show that the cross‐steam flow in a strongly curved pipe can be as large as 80% of the bulk average velocity at θ = 45° but is reduced in magnitude between θ = 45° and 90°.

The numerical procedure used for the present calculations is a special case of a more general method which will solve flows in arbitrary curvilinear orthogonal coordinates provided the appropriate scale factors and extra source terms are included. A detailed derivation of the difference equations in curvilinear orthogonal coordinates is, therefore, presented here.
Hydrocracking of bitumen and heavy oils at CANMET
Authors: Pruden B. B.
Published: March 2009

A description of pilot‐plant scale investigations of thermal and catalytic hydrocracking of bitumen and heavy oil at the Energy Research Laboratories, Canada Centre for Mineral and Energy Technology, is presented. A summary of division programs in the high pressure hydrogenation area since 1930, and current in‐house and “contract” activities are outlined.
Noncatalytic gas‐solid reaction with changing particle size: Unsteady state heat transfer
Authors: Rehmat A. , Saxena S. C. , Land R. , Jonke A. A.
Published: March 2009

A mathematical expression for the unsteady state heat balance is derived for a nonisothermal, noncatalytic, first order gas‐solid reaction. The formulation is based on a shrinking core model and takes into account the changing size of the spherical particle during reaction. Thus, the model has two moving boundaries, viz., the reaction front and the external particle diameter which grows or shrinks due to reaction. This complicates the numerical solution considerably. The calculations indicate that both the conversion‐time relationship and core temperature are significantly influenced by the extent of particle growth. The unsteady state and quasi‐steady state analyses lead to somewhat similar results for conversion‐time relationship except for the case where the solid reactant has a large heat capacity. On the other hand, the core temperatures for the two cases differ significantly.
Isobaric liquid‐vapour equilibrium data correlation for a ternary mixture exhibiting associations: Acetic acid‐acetone‐trichloroethylene
Authors: Francesconi Romolo , Comelli Fabio , Montefusco Laura , Trevissoi Carlo
Published: March 2009

Liquid ‐ vapour equilibrium data (temperature and composition in the liquid and vapour phases) of the ternary mixture: acetic acid ‐ acetone ‐ trichloroethylene, which exhibits association of the acid even in the vapour phase, were determined at P = 93.3 kPa (700 mmHg) with the Stage‐Muller apparatus. The thermodynamic consistency of these data was tested by means of the McDermott‐Ellis test, and the activity coefficients of the three components were correlated with Margules' and Wilson's Equations, the parameters of which were evaluated by a least square procedure. The parameters having been thus evaluated, Margules' and Wilson's Equations were then used to recalculate the equilibrium compositions. The value of the standard deviation Δξ between the experimental and calculated composition indicates that Margules' Equation permits a better correlation of the data than Wilson's. Moreover, Margules' Equation with parameter Aij and C* evaluated by the ternary data gives lower values of Δξ than the same Equation, but with parameters Aij evaluated by the binary data and C* by the ternary data with binary Aij, according to the method normally employed.
Une éequation d'éetat de clausius modifiée repréeasentant l'éeatat liquide
Authors: Freze Richard , Chevalier Jean‐Louis
Published: March 2009

Les trois paramètres d'une équation d'état de Clausius modifiée ont été généralisés, en ayant pour objectif le calcul des propriétés thermodynamiques des corps purs dans l'état saturé, depuis la température d'ébullition normale jusqu'à la température critique. La méthode décrite, qui nécessite la seule connaissance des propriétés caractéristiques des corps purs (Tc, Pc, Zc, ω) a été testée sur 28 composés divers (hydrocarbures saturés et insaturés, molécules simples et molécules polaires). Les résultats obtenus montrent que l'équation d'état proposée décrit correctement l'équilibre liquide‐vapeur (pression de vapeur saturante et enthalpie de vaporisation) et elle permet de plus une représentation satisfaisante de l'état liquide saturé.
The effect of high magnetic fields on the vapour liquid equilibrium data for nitrogen/oxygen
Authors: Biddulph M. W. , Meachin A. J.
Published: March 2009

This paper describes an experimental study carried out to check the effect of high magnetic fields on the vapour liquid equilibrium of N2/O2. Significant effects were measured on the VLE curves, although these did not correspond to the earlier theory of Atroshchenko and Voronina(1). This theory used a predicted effect on the vapour‐pressures of the pure components. The equilibrium cell is described in detail and the data measured showed increasing non‐ideality with increasing field strength due to an effect mainly on the liquid phase.
Evaluation of capital cost data: Gas moving equipment
Authors: Woods Donald R. , Anderson Susan J. , Norman Suzanne L.
Published: March 2009

Capital cost correlations are given for gas moving equipment. Correlations available in the literature and current data are compared on a consistent basis. Forty‐three graphs show the relative magnitude of the different correlations and the recommended correlation for each type of equipment is summarized in a table. Some data on the costs of installing gas moving equipment are given.
Breakage rates of lignite particles during hydraulic transport
Authors: Shook C.A. , Haas D.B. , Husband W.H.W. , Small M.
Published: March 2009

Experiments conducted with recirculating test loops show that the rate equations for rod and ball mill grinding can be applied to the changes induced by pumping. Selection rate constants in the range considered were found to be rather insensitive to particle size but strongly time dependent. This time dependence can be attributed to changes in particle shape dominating over fracture as a degradation mechanism. Pump construction and speed appeared to be of considerable importance in determining breakage rates.
A technique for the determination of the concentration distribution in a sedimenting suspension via radioactive solids
Authors: Tory Elmer M. , Mosevich Jack W. , Reddy V. Malla
Published: March 2009

In a slurry of radioactive particles, radiation count and solids concentration are related by a Fredholm equation of the first kind. Two iterative methods are described and conditions for their convergence are given. Two hypothetical examples illustrate computational difficulties and their solution. Experiments with slurries of radioactive praseodymium oxalate demonstrate the feasibility of the method. Solutions are proposed for various practical problems which arise.