bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential pitfalls in model discrimination
Authors: Pritchard D. J. , Bacon D. W. 
Published: March 2009

AbstractStatistical experimental design techniques for model discrimination are evaluated using data obtained by Juusola (1971) for the oxidation of o‐xylene over a vanadium oxide catalyst. The Box‐Hill (1967) design procedure for discrimination is found to be particularly sensitive to underestimation of the variance of the measured response. An analogous weighted criterion is developed and found to perform satisfactorily with data fitted using weighted least squares. Other numerical difficulties encountered in using the discrimination design criteria are also discussed.
Motion of solids in spouted beds
Authors: Van Velzen D. , Flamm H. J. , Langenkamp H. , Casile A. 
Published: March 2009

AbstractSolids movement in a spouted bed has been investigated by means of a radioactively marked particle technique, using a scintillation counter as a detector.The average particle velocity in the spout was found to depend on gas flow rate, gas inlet geometry, axial elevation, bed height, and column diameter.The solids circulation rate is shown to be proportional to the gas flow rate and, further, a function of column and gas inlet geometry, density of fluidising gas and particle diameter.Empirical correlations for both the particle velocity in the spout and the solids circulation rate as a function of axial elevation, are presented.
Odour control from a kraft mill lime kiln using a spouted bed pre‐drier
Authors: Prakash C. B. , Mathur K. B. , Murray F. E. 
Published: March 2009

AbstractA study has been conducted on the drying of lime mud and the concurrent oxidation of sodium sulphide in the mud. The experiments were done using a 6″ dia spouted bed of coarse inert particles (cement clinker and limestone; —4 + 10 mesh) with continuous feed of lime mud. A range of inlet gas temperatures, from 260°F to 400°F, was studied. A high degree of sulphide oxidation was achieved by this method over the entire temperature range, sulphide removal being in excess of 80% in all runs and as high as 98% in some.An analysis of the economic feasibility of drying lime mud in a spouted bed indicates that the process has good potential both as a method for drying lime mud prior to calcining and for control of hydrogen sulphide emission from lime kilns operated at kraft pulp mills.
Application of the parallel disc model for uneven film thinning
Authors: Liem Albert J. S. , Woods Donald R. 
Published: March 2009

AbstractThe use of the parallel disc model is extended to allow for partial mobility of the interfaces to describe thinning at the thinnest point of an unevenly draining film.Various methods of describing partial mobility are described and compared. The model predicts satisfactorily the observed film thinning (measured by the light interference method) for toluene/water systems containing zero, 10−6M and 10−4M palmitic acid with toluene drops ranging from 0.0025 to 0.005 ml and an anisole/water system with 0.015 ml anisole drop. The trend of change of the calculated partial mobility is consistent with the expected liquid/liquid interface behavior during thinning.
Laminar forced convection in the thermal entrance region of curved pipes with uniform wall temperature
Authors: Akiyama Mitsunobu , Cheng K. C. 
Published: March 2009

AbstractThe thermal entrance region heat transfer problem for fully developed laminar flow in curved pipes with uniform wall temperature is approached by an alternating direction implicit method for the parabolic energy equation for a flow regime with Dean number ranging from 0 to an order of 100. This work represents an extension of the classical Graetz problem in straight tubes to curved pipes. The graphical results for temperature developments in the form of temperature profiles through the horizontal and vertical planes, isothermals and local Nusselt number variations in the thermal entrance region are presented in such a way as to illustrate clearly the interaction between the secondary flow and the developing temperature field for Prandtl numbers of 0.1, 0.7, 10 and 500. For a given Dean number, the effect of Prandtl number is to shorten the thermal entrance length (I/Gz) and the temperature field develops rather rapidly with large Prandtl number. The effect of Dean number is similar to that of Prandtl number with Dean number effect becoming much more appreciable at high Prantdl numbers than at low Prandtl number.
Rates of isotopic exchange between hydrogen and aminomethane catalyzed by potassium methylamide
Authors: Kalra Harish , Otto Fred D. 
Published: March 2009

AbstractPseudo first order kinetic constants for the exchange of deuterium between hydrogen and aminomethane were determined from measurements of the rates of absorption of hydrogen deuteride into liquid aminomethane flowing over a sphere. Potassium methylamide dissolved in the amine catalyzed the reaction. Kinetic constants range from 130 to 650 sec−1 at temperatures from —30° to —10°C and catalyst concentrations of 4.95 to 15.8 g K/kg amine.
Shear deagglomeration of solid aggregates suspended in viscous liquids
Authors: Patterson I. , Kamal Musa R. 
Published: March 2009

AbstractThe paper deals with the deagglomeration process in viscous fluids. The process is that in which aggregates of particles suspended in fluids are broken in a shear field. A mathematical model is proposed to predict the equilibrium particle size distribution as a function of shear stress, the initial particle size distribution and the agglomerate strength distribution. Experimental work was performed to test the model. A concentric cylinder apparatus provided the shear field and a procedure was developed to determine the agglomerate size distribution. Artificial agglomerates were prepared by a novel method. Within the limitations of experimental and sampling errors, the calculations agree with experimental results.
Water activity data representation of aqueous solutions at 25°C
Authors: Teng Tjoon‐Tow , Lenzi Fabio 
Published: March 2009

AbstractPolynomial expressions have been fitted to the complete range of available water‐activity data for 396 electrolyte and non‐electrolyte aqueous binary systems. The standard deviation of regression rarely exceeded 0.001 and was less than 0.0002 in most cases. Such data representation is useful for the prediction of the water‐activity of mixed moderately concentrated aqueous solutions.
Vertical two‐phase flow: Part II. Holdup and pressure drop
Authors: Oshinowo Toks , Charles M. E. 
Published: March 2009

AbstractTwo‐phase gas‐liquid flow has been investigated in a 1‐inch internal diameter vertical tube coil containing two risers and a downcomer all connected by “U” bends. Pressure drop, holdup and flow pattern data were successfully obtained simultaneously in the three vertical tubes, each 17.30 ft. long, for five different air‐liquid systems at about 25 psia and 50°F‐80°F over flow ranges of 0–700 lbmair/min‐ft2and 140‐‐25300 lbmliquid/min‐ft2.Pressure drops and liquid holdups were plotted against gas volume flowrate with liquid flowrate as a parameter. From these plots it was found that for a combination of an increase in liquid viscosity and density, and a decrease in surface tension, the frictional pressure drop increased in down flow and decreased in upflow. Holdup, on the other hand, increased for both types of vertical flow with respect to the same combination of parameters.The Lockhart‐Martinelli scheme was satisfactory in correlating frictional pressure drop and holdup in all the flow regimes except the frothy‐slug regime in upflow. In downflow however, the Lockhart‐Martinelli scheme met with limited success because of a strong influence of liquid flowrate, physical properties and pipe orientation.Holdup in the falling film and falling bubbly film regimes in downflow were satisfactorily treated by the drift flux approach which emphasizes the relative motion of the two phases.
Experimental study of the internal fluid dynamics of forming drops
Authors: Humphrey J. A. C. , Hummel R. L. , Smith J. W. 
Published: March 2009

AbstractA non‐disturbing photochromic flow visualization technique has been used to study fluid flow conditions within the vertical core region of organic liquid drops growing from a single nozzle in an equilibrated water phase. The indicator 1,3,3‐trimethylindolino‐6′‐nitrobenzopyrospiran (0.015%), which was dissolved in the dispersed phase produced extremely fine tracer lines in the drops when irradiated with UV light from a multipulse nitrogen laser. High speed cinephotographs of the observed time lines were used to estimate axial and radial velocity components by means of a numerical mass balance technique. By substitution in the Navier‐Stokes equations it is shown how the axial and radial pressure change distributions may be obtained from the velocity measurements.
Minimizing the pressure gradients in capsule pipelines
Authors: Ellis H. S. , Kruyer Jan 
Published: March 2009

AbstractThe pressure gradients due to cylindrical capsules were reduced by up to 80% by providing them with plastic instead of steel surfaces or by fitting them with collars. The power requirements of a capsule pipeline depend greatly on the capsule density, and if the capsules were constructed so that a third of the volume consisted of voids, the power needed to transport two teragrammes (2 million tons)/year of solid with a density of 1500 kg.m−3 (S.G. = 1.50) in a 254 mm (10 in.) pipeline would be reduced by over 90%. The pressure gradients and power required to transport spherical capsules were generally much smaller than those required for even the smoothest cylinders of the same specific gravity.
Electrothermal fluidized bed chlorination of zircon
Authors: Manieh Atef A. , Scott D. S. , Spink D. R. 
Published: March 2009

AbstractZircon sand, ZrSiO4, is chlorinated in an electrothermally‐heated fluidized bed reactor using calcined petroleum coke as the reducing agent and chlorine as the chlorinating agent. The electrothermally‐heated fluidized bed reactor proved to be versatile and effective for the chlorination of zircon sand.The rate of the reaction can be expressed by the formula

The reaction was found to be of zero order with respect to the chlorine concentration, which suggests that chlorine is strongly adsorbed on the solid particles; as such, the concentration of chlorine in the gas phase has no effect on the reaction rate.The activation energy for the reaction was found to be 10.55 Kcal/gram mole which is indicative of control by the rate of a surface reaction or adsorption step.
Kinetics of bio‐oxidation of metal sulphides
Authors: Torma A. E. , Legault G. , Kougioumoutzakis D. , Ouellet R. 
Published: March 2009

AbstractThe microbiological oxidation of cadmium, cobalt, nickel and zinc sulphides has been investigated using a pure strain of Thiobacillus ferrooxidans. Kinetic parameters (Vm and K) have been derived regarding the effect of initial total surface area of these substrates. A relationship is suggested to exist between the rate of sulphide oxidation and the solubility product of the respective metal sulphide.
Laminar natural convection caused by chemical diffusion and reaction from a vertical plane surface
Authors: Meadley C. K. , Rahman M. 
Published: March 2009

AbstractA theoretical study of laminar natural convection over a semi‐infinite vertical plate is presented. The plate is of given, uniform concentration in some chemical species and convection is induced by diffusion into and chemical reaction with the ambient fluid. Steady state conditions are assumed. The equations used are basically those of the two‐dimensional boundary layer theory, modified to accommodate binary diffusion by Fick's second law, the Boussinesq approximation and homogeneous, irreversible isothermal reaction kinetics. A similarity transform to one variable is possible in the absence of chemical reaction; otherwise the problem is solved by perturbation expansions about an additional similarity variable which is dependent on the reaction rate. It is shown that the Schmidt number Sc and the reaction order n are the two fundamental parameters of the problem. Some analytical and numerical solutions are given for the ranges 10−2≤ Sc ≤ 104and 0 ≤ n ≤ 2. Calculations are presented in the form of graphs showing the concentration and flow fields within the convection layer. Generally it is found that the presence of chemical reaction expands the diffusion and velocity domains out from the plate, resulting in a larger, while less distinct, convection layer.
Heat transfer effects on drying rate of food dehydration
Authors: Vaccarezza Luis M. , Lombardi Jose L. , Chirife Jorge 
Published: March 2009

AbstractThis work studies the consequences of neglecting heat transfer effects in the Fick's law solution of food dehydration problems. A semi‐empirical approach is presented which correlates temperature and moisture changes of sugar beet root during the first falling rate period of drying; while the coupled heat and mass transfer equations are not solved rigorously, the approach gives a fairly accurate representation of the experimental results. An improved analysis through Fick's law is possible when the effect of changing sample temperature is considered.
Additive excess free energy models for predicting gas solubilities in mixed solvents
Authors: Puri P. S. , Ruether J. A. 
Published: March 2009

AbstractNew data are reported for the solubility of hydrogen in the solvent binaries: acetone‐isopropanol, acetone‐cyclohexane, and acetone benzene at 25°C and one atmosphere pressure. Models for predicting mixed solvent Henry's law constants which utilize solvent vapor‐liquid equilibrium data are reviewed, and a new model based on the van Laar equation is proposed. The new data and selected data from the literature are used to evaluate the models. For the six systems tested, the proposed model gives the best results, with the assumption of ideality (Krischevsky equation) being nearly as good.
Capture of monodispersed aerosol particles in a fixed and in a fluidized bed
Authors: Knettig P. , Beeckmans J. M. 
Published: March 2009

AbstractA study was made on the capture of monodispersed aerosol particles in the size range 0.8 ‐ 2.9 μm, in a screen‐supported fixed bed, and in a fixed and a fluidized bed supported on a grid of low superficial area (0.56%). All beds were composed of glass beads of mean size 425 μm. Relatively high capture efficiency was observed in the grid regions of both fixed and fluidized beds supported in this manner, with relatively lower capture efficiency observed in the vicinity of the screen. Aerosol capture efficiency per unit of bed volume in the body of the fixed beds was not significantly affected by the method of support, and was larger than was the case with the fluidized bed. An estimate of aerosol capture efficiency at the grid jets, based on an equivalent pneumatic transport line concept, was in reasonable agreement with experiment.
Longitudinal mixing in a vibrating‐sieve‐plate column two‐phase flow
Authors: Nemecek Milan , Prochazka Jaroslav 
Published: March 2009

AbstractLongitudinal mixing in the continuous phase of a vibrating‐plate extractor was examined. Particular attention was focused on the effect of the flow of the dispersed phase, which turned out to be of major importance. Three regimes displaying distinctly different character of longitudinal mixing may be observed. The flow within a stage was studied in detail and it was shown that the stage could split into two regions of different character of the flow. A model was proposed which makes up the total effect of longitudinal mixing from the back flow through the plate plus axial dispersion within the stage. Correlations have been proposed relating the axial dispersion coefficient to the hold‐up and droplet diameter.
Packed extraction columns: A review of correlations for maximum throughput
Authors: Houlihan R. , Landau J. 
Published: March 2009

AbstractA considerable amount of experimental data on maximum flow rates of countercurrently flowing liquid phases in packed columns has been published and a number of correlations for flooding velocities have been proposed. In the present paper various correlations are tested, using the same set of experimental results selected according to plausible criteria. The results of the test are presented in a consistent manner. Reasons why the result arrived at in this review differ from the recommendation given in Reference 10 are discussed.
Etude expérimentale du micromélange à l'aide d'un traceur non‐réactif dans un réacteur agité
Authors: Truong  , Trong Khac , Methot J.‐Claude 
Published: March 2009

AbstractOn étudic le niveau de micromélange dans un réacteur muni de quatre chicanes et d'un agitateur à turbine à l'aide de la technique d'injection échelon d'un traceur ionique non‐réactif. Une sonde conductimétrique à haute résolution spatiale a été utilisée pour détecter les fluctuations de concentrations résultant de la turbulence. L'approche phénoménologique basée sur la collision et redispersion des agrégats de fluide a été mise en évidence expérimentalement. Une évaluation directe du degré de ségrégation a été effectuée et l'ordre de grandeur trouvé (J varie de 10−3 à 10−5) a indiqué que le réacteur expérimental était à l'état de mélange maximal.
The effects of intraparticle diffusion on the kinetics of gel entrapped enzymes
Authors: Korus R. , O'Driscoll K. F. 
Published: March 2009

AbstractThe results of a theoretical treatment are given for the effect of intraparticle diffusion on the Michaelis‐Menten kinetic behaviour of enzymes entrapped in spherical hydrogel particles. It is shown that curvature in Lineweaver‐Burk plots may be expected, and that the influence of particle size on the activity of entrapped enzymes may be predicted. The effectiveness factor is discussed and analogies with heterogeneous catalysis noted. Experimental results are presented for the hydrolyses of model substrates by gel entrapped trypsin, β‐galactosidase, glucose oxidase and urease which are consistent with the theoretical treatment.
Methods of estimating the water activity of supersaturated aqueous solutions
Authors: Tran Tuong‐Tu , Lenzi Fabio 
Published: March 2009

AbstractEmpirical and semi‐empirical methods of estimating the water activity of supersaturated aqueous solutions at up to twice the saturation molality are compared for CaCl2 and Na2SO4 at °0C and K2SO4, KH2PO4, NaCl, KCl, RbCl, CsCl, KNO3 and mannitol at 25°. An empirical method, applicable to both electrolytes and non‐electrolytes, is described.
The solubility of H2S and CO2 in aqueous monoethanolamine solutions
Authors: Lee J. I. , Otto F. D. , Mather A. E. 
Published: March 2009

AbstractThe solubility of hydrogen sulphide and carbon dioxide, respectively, in 2.5 and 5.0 N aqueous monoethanolamine solutions has been determined at temperatures of 40°C and 100°C. Partial pressures of CO2 ranged from 0.1 to 1000 psia, while partial pressures of H2S ranged from 0.3 to 650 psia. The results have been used, together with literature data, to calculate enthalpies of solution.
Control of a binary distillation column utilizing a simple control law
Authors: McGinnis R. G. , Wood R. K. 
Published: March 2009

AbstractMultivariable control of overhead and bottoms composition of a binary distillation column subjected to feed flow disturbances has been studied. The study has been performed using a pilot scale column, equipped with overhead and bottoms composition analyzers, operated under the control of an IBM 1800 digital computer. The column dynamic behavior, for control law calculation, was approximated by a two state variable model. Experimental results employing multivariable feedback and multivariable feedforward‐feedback control laws are presented.
Optimization by distributed control of reactors with decaying catalyst Part I: Non‐linear catalyst deactivation
Authors: Therien N. , Crowe C. M. 
Published: March 2009

AbstractThe quasi‐steady state optimization of a single tubular fixed bed reactor with a slowly decaying catalyst is considered.The optimal choice of temperature T(z, t) distributed in both the space of the reactor and in chronological time is sought so as to maximize the total amount of reaction in a fixed given period of time.A single irreversible reaction is considered with a rate expressible as a product of separate functions of temperature, activity and conversion. The rate of catalyst decay is also a product of separate functions of temperature and activity but independent of conversion. Upper and lower bounds are placed on the permitted temperature. Theoretical characterization of the optimal policy is obtained using Sirazetdinov and Degtyarev's maximum principle derived for first‐order partial differential equations and the influence of the ratio of reaction activation energy to catalyst deactivation energy on the derived optimal policy is indicated.Numerical calculations are presented to illustrate the optimal policies.
Simultaneous heat and mass transfer in spouted beds
Authors: Kmiec Andrzej 
Published: March 2009

AbstractThe results of a fluid‐particle heat and mass transfer study in air spouted beds of silica gel and activated coal particles, using a 9 cm I.D. column with a 30° and 90° conical base, are reported. The effects of gas velocity, particle size, bed depth and cone angle on the heat and mass transfer coefficients are discussed. Equations correlating heat and mass transfer coefficients have been established. The ratio (jn)s/(jD)8 has been found to be dependent on the Reynolds number and the system of spouting.
Wall mass transfer in horizontal slurry pipelines
Authors: Postlethwaite John , Holdner D. N. 
Published: March 2009

AbstractMeasurements have been made of the rate of mass transfer of dissolved oxygen to the walls of 5 cm diameter horizontal pipes carrying aqueous slurries of sand and iron ore, in the concentration range 10 — 20 vol % at velocities up to twice the critical value for deposition. The results which show that the suspended particles greatly increase the rate of mass transfer are discussed in terms of the analogies and are compared with the results of previous workers for heat and momentum transfer. In the case of mass transfer in systems with high Schmidt numbers it appears that there is a specific effect of the solid particles relating to the disruption of the viscous sub‐layer.
Electrochemical wall mass transfer in liquid particulate systems
Authors: Smith J. W. , King D. H. 
Published: March 2009

AbstractIonic mass transfer coefficients between the wall of a 2.081 inch tube and liquid fluidized beds of lead glass, soda glass and lucite spheres have been measured using the diffusion‐controlled reduction of ferricyanide ion at a nickel cathode for porosities 0.90 to 0.45 and Schmidt numbers 580 to 2100.The developed fluidization mass transfer coefficient for 41 < DT/dp < 105 were correlated by iD E = 0.274 ReH−0.38 for 10 < ReH <1600 and by JD E = 0.455 ReH−0.44 for 16.7 < DT/dp < 27 and 50 < ReH < 3500. ReH is the hydraulic Reynolds number = dH up/μE and dH is DT E/[1 + (3/2) ((1–E)) (DT/dp)).The distinct effect of DT/dp ratio is attributed to wall effects and the non‐particulate behaviour of the fluidized bed for DT/dp < 27.Measurements in the open pipe and packed bed agreed very well with literature values. The packed bed gives highest mass transfer coefficients at given ReH.
SO2 promoted oxidative dehydrogenation of ethylbenzene
Authors: Gaspar N. J. , Vadekar M. , Pasternak I. S. , Cohen A. D. 
Published: March 2009

AbstractIt has been demonstrated that SO2 acts as an efficient dehydrogenation agent in the conversion of ethylbenzene to styrene in the presence of alkali and alkaline earth metal oxide doped alumina and titania catalysts. Development of these catalysts, which give styrene yields of greater than 80% per pass, is described in the paper. The catalysts allow the use of close to stoichiometric amounts of sulphur dioxide, are active in the presence of steam diluent and show low deactivation with time. The effect of varying process conditions such as temperature, reactant concentration and diluent amount is also described.