bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparaison du modèle des réservoirs imparfaitement agités en série avec le modèle de dispersion axiale
Authors: Bang Vo Van , Cholette A. 
Published: March 2009

AbstractOn présent la fonction de transfert du modèle des réservoirs imparfaitement agités en série, comportant les trois paramètres p, m et n. Elle permet d'évaluer facilement la courbe de distribution du temps de séjour E(θ) et la réponse à une demande à l'entrée.Ce modèle est comparé au modèle de dispersion en se basant sur la variance de la courbe E(θ) et sur l'erreur moyeune absolue entre les valeurs théoriques et les données expérimentales. Un graphique permet de relier le nombre de Péclet du modèle de dispersion axiale aux paramètres du modèle p, m, n et aussi à la variance de la courbe E(θ).Le modèle p, m, n donne une bonne approximation des données expérimentales et s'avère plus souple que le modèle de dispersion axiale.
A cationic surfactant as a soluble ion exchanger in the continuous foam fractionation of nitrate; iodide, and bromide
Authors: Grieves R. B. , Bhattacharyya D. , The P. J. W. 
Published: March 2009

AbstractAn experimental investigation is presented of the continuous foam fractionation of NO3− versus Br− and of T− versus Br− with a quaternary ammonium surfactant at concentrations of the order 1.8 × 10−4M. An equation is derived to enable the computation of anion selectivity coefficients from foam fractionation data. The key assumptions of the derivation are verified experimentally. The selectivity coefficient for NO3 versus Br− is 1.56 ± 0.28 and for I− versus Br− is 5.85 ± 1.81, established from 40 continuous‐flow experiments. Precipitation of EHDA‐I is indicated at the highest ratios of the bulk solution concentrations of I− and Br−. significantly, both selectivity coefficients are independent of the fraction of the exchanger occupied by the preferred ion, indicating an exchanger activity coefficient ratio of unity, and are independent of ionic strength. The counterion present markedly influences the surfactant distribution coefficient.
Removal of fine particles from water by dispersed air flotation: Effects of bubble size and particle size on collection efficiency
Authors: Reay David , Ratcliff G. A. 
Published: March 2009

AbstractA theoretical treatment is presented which attempts to quantify the benefits obtained by using smaller bubbles or larger particles in dispersed air flotation. The limited experimental data obtained so far suggest that the theory is sound, particularly in its prediction of the effect of bubble size.
Submerged culture growth of edible mushrooms on waste sulphite liquors
Authors: Kosaric N. , Leduy Anh , Zajic J. E. 
Published: March 2009

AbstractVarious waste sulphite liquors (WSL) i.e. NH3−, Mg‐, Ca‐, and mixed‐base, were used as substrates for submerged cultivation of four species of edible mushrooms (morel mushroom): Morchella spp., Morchella crassipes, Morchella deliciosa, Morchella esculenta. Growth was found to be completely inhibited by calcium found in both Ca‐WSL and mixed‐WSL. (In NH3− WSL and Mg‐WSL growth generally occurs in large pellet form.The optimal initial pH for the different morel species on various WSL was found to be between 5.0 and 7.0. The highest yield (approximately 83.4% based on utilized carbohydrate) and dry weight (approximately 4.86 g/l) were obtained when the NH3− WSL was diluted (1:5 v/v) and used for growth of Morchella crassipes. Freeze‐dried morel mushroom mycelium (MMM) on WSL contains on a dry basis, 25.7‐48.0% crude protein, 2.45‐4.38% fat, 13.7‐39.2% carbohydrate and 5.9‐18.0% ash. The spectrum of essential amino acids is comparable to the FAO standard, except for the levels of methionine and isoleucine. A strong mushroom flavor (aroma and taste) is also conserved in freeze‐dried powdered samples.
Equilibre entre vapeur et liquide pour le système azote‐argon‐methane
Authors: Gravelle Denis , Lu Benjamin C.‐Y. 
Published: March 2009

AbstractOn a mesuré au moyen d'un apparcil à re‐circulation forcée les compositions d'equilibre entre la vapeur et le liquide pour le système azote‐argon‐méthane à 123.4°K.Les résultats obtenus de cet appareil ont été représentés avec succès par l'équation d'état de Redlich‐Kwong. On a modifié celle‐ci en y incurporant unc constante d'action réciproque binaire kij et en considérant les constantes caractéristiques de l'équation Ωa et Ωb comme étant fonction de la température, pour chaque composant. On a aussi évalué les constantes d'équilibre à partir de l'équation d'état pour ensuite les comparer avec les valeurs experinientales. Les moyennes absolues des déviations sont 1.62%, 1.67% et 7.57% pour les composants azote, argon et méthane respectivement.
Transition to unsteady flow and intensity of velocity fluctuations in a porous medium
Authors: Kingston George , Nunge Richard J. 
Published: March 2009

AbstractDirect measurements of local velocity and the intensity of velocity fluctuations in a pore of a number three rhombohedral array of spheres indicate a region of increasing intensity beginning at Reynolds number of about 80 and reaching a maximum intensity of approximately 0.6 at a Reynolds number of about 200. At higher Reynolds numbers the intensity falls to a constant value between 0.4 and 0.5.
An empirical equation of state for gases
Authors: Sandri R. 
Published: March 2009

AbstractA simple pressure‐explicit empirical equation of state for gases is presented which contains five constants in addition to the gas constant. It has been applied to carbon dioxide, hydrogen and nitrogen. The equation gives good accuracy (with maximum errors slightly higher than 1%) for densities up to critical and for temperatures from slightly above critical up to very high values. Below critical temperature it can still be applied with reasonable accuracy to the vapor. Thermodynamic functions (internal energy, enthalpy and entropy) derived from this equation show simple form and satisfactory accuracy over a wide range of temperature and density.
An analysis of horizontal stratified two phase flow in pipes
Authors: Agrawal S. S. , Gregory G. A. , Govier G. W. 
Published: March 2009

AbstractUsing a mechanistic approach, equations are developed to describe the stratified cocurrent flow of gas‐liquid mixtures in horizontal pipes. An iterative method is suggested for their solution.Experimental data were collected using air‐oil mixtures in a one inch 1. D. by 101 ft. long acrylic pipe. Pressure drop and average in situ liquid volume fraction are presented as a function of the superficial gas velocity and are compared with predicted results from this study and other models reported in the literature.Visual observation of flow patterns and their transitions are indicated on the tentative flow pattern map of Govier and Aziz(1).
Solubilities of the highly soluble gases, propane and butane, in normal paraffin and polar solvents
Authors: Hayduk W. , Castaneda R. 
Published: March 2009

AbstractThe solubility of highly soluble gases in both polar and non‐polar solvents has been found to approach a mole fraction of unity as the solution temperature is reduced toward the normal boiling point of the dissolved gas. Solubilities of all gases in the polar solvents chlorobenzene, normal butanol and acetone, tend toward a common reference solubility for each solvent as the temperature is increased toward the solvent critical temperature. Solubilities of propane as measured in this work are reported at 0°C, 25°C and 50°C in chlorobenzene, butanol and acetone and at 25°C in hexane and hexadecane, along with solubilities of butane at 5°C, 25°C and 50°C in hexane, heptane, octane, dodecane, hexadecane and butanol. These data, along with those from literature sources, have been utilized in formulating the above generalizations.
Quantitative analogies between the linear and non‐linear viscoelastic functions
Authors: Hlavacek B. , Seyer F. A. , Stanislav I. 
Published: March 2009

AbstractA method of determination of linear and non‐linear viscoelastic functions is proposed. Through this method it is possible to calculate the non‐linear functions P11 ‐ P22 and η(γ) assuming that linear viscoelastic function (ω) is known. Alternatively from the function P11 ‐ P22 we are able to calculate η(γ) and y'(ω) etc.The method is based on the assumption that the change from linear to non‐linear functions is proportional to a molecular deformation for shear stress components P12, and is dependent on the square of the deformation for the first normal stress difference, P11 ‐ P22. The obtained results suggest straightforward modification of equations of state, this being demonstrated with the White‐Metzner model of the convected Maxwell element.Consideration of available experimental data shows that this theory is capable of predicting the various functions, at least as well as currently available constitutive equations, while requiring less experimental information.
The non‐adiabatic tubular reactor: Stability considerations
Authors: Varma Arvind , Amundson Neal R. 
Published: March 2009

AbstractThis paper is a continuation of four previous ones in this journal (1, 2, 3, 4) and is involved with the transient and stability behavior of a non‐adiabatic unpacked tubular reactor. The steady states found earlier are tested for stability both by computing transient profiles and by computing the eigenvalues of the appropriate linearized problem. It is found in all cases that the two computations predict the proper stability behavior. It is shown that in some cases all steady states for a given set of parameters may be unstable and that a unique steady state may give rise to an oscillatory system.
The chemical engineering approach to some electrochemical processes
Authors: Fahidy T. Z. 
Published: March 2009

AbstractIn recent years much research has been carried out in combining electrochemical processes with chemical engineering techniques, and in general, to apply principles of analysis and design of this discipline in search for new electrochemical technologies. This paper reviews seven major areas of activity in modern applied electrochemistry where the chemical engineering approach has been successful: Fluidized bed electrochemical reactors; Bipolar particulate reactors; Pulsed electrochemical reactors; Gas phase electrochemical reactors; Electrocrystallization and electrodissolution; Enhancement of heat and mass transfer in electric fields; dynamics, modelling and optimization of electrochemical reactors.
Amino sulphonic resins for chlorine exchange
Authors: Wayman Morris , Cheung Leon K. L. 
Published: March 2009

AbstractThe introduction of sulphonic groups to urea melamineformaldehyde resins has been shown to improve their performance as chlorine exchange resins for treatment of drinking and swimming pool waters. The preparation of resins containing a range of sulphonic content (UMFS resins) is described. Suspension polymerization produced resin beads suitable for use in fluidized beds. Scanning electron microscopy showed the resin structure to be macroreticular, porosity increasing with the sulphonic content in the formulation. Chlorination of water by fluidized beds of such resins showed that the activity increased with sulphonic content, steady state residual chlorine levels of 2 to 4 ppm being obtained with 0.5 or 1 mole sulphonic group per mole urea in the formulation.
Growth of a sulphuric acid droplet exposed to water vapor
Authors: Azarniouch M. K. , Bobkowicz A. J. , Cooke N. E. , Farkas E. J. 
Published: March 2009

AbstractThe growth of a droplet of concentrated sulphuric acid suddenly exposed to water vapor was investigated. Droplet size and temperature as functions of time were obtained by numerical solution of droplet mass and energy balances. Inclusion of heat effects is thought to be an advance over previous studies of droplets of dilute acid which could be assumed to remain isothermal during the growth process. The results indicate that the growth process is completed in a few milliseconds for micron‐size droplets. The solutions presented are applicable to the continuum regime and the results are compared with experimental and calculated results of previous workers.
A general algorithm for multistage multicomponent separation calculations
Authors: Ishii Yoshikazu , Otto Fred D. 
Published: March 2009

AbstractThis paper presents a new general calculational method for equilibrium stage processes. The method employs a multivariate Newton procedure to solve all equations simultaneously for corrections to temperatures, flow rates and compositions. The linearized model equations are selected so that only 2N (1 + NCP) partial derivatives need to be evaluated per iteration. Experience to date indicates that the method is reliable for both distillation and absorption problems and requires less computing time than current procedures. The rigorous solution of a reboiled absorber problem for 16 stages and 15 components required 5 iterations and 14.4 seconds on an IBM 360/67 computer even when the Chao‐Seader correlation was employed for the direct calculation of composition dependent equilibrium and enthalpy data.
Geometry of bluff body wakes
Authors: Kalra T. R. , Uhlherr P. H. T. 
Published: March 2009

AbstractThe attached recirculating wake zone has been experimentally investigated for spheres, spherical caps and circular discs normal to the flow. Tracer photography in a water tunnel was employed for the measurements. Results are presented over the range of Reynolds number from 20 to 400. The following wake properties are presented as a function of Reynolds number: angle of separation for spheres; wake length for spheres and discs, wake volume for all three types of body.The results for separation angle are in good agreement with the data available from the literature, both experimental and theoretical. Wake length results for spheres are also in agreement with published values and with values obtained from published numerical solutions of the equations of motion. Wake volume results for spheres are similarly in agreement with values calculated from published wake dimensions obtained both experimentally and theoretically.Spherical caps are found to have the wake volume either of discs if they are thin (h/D <0.3) or of spheres if they are thick (h/D > 0.6). Caps of intermediate thickness to diameter ratio show a transition between sphere‐like and disc‐like behavior. This behavior is explained in terms of the separation angle on spheres.
Frequency response in liquid fluidized systems Part I. Effect of particle density and size
Authors: Krishnaswamy P. R. , Shemilt L. W. 
Published: March 2009

AbstractFluid mixing in liquid fluidized beds has been characterized by a dynamic response technique using pulse inputs. Solid particles with a size range of 0.5 to 3.0 mm diameter and a density range from 1.28 to 7.02 gms/cc were fluidized with water at void fractions of 0.4 to 0.85 in a 2‐inch column. A dispersed plug flow model has been applied successfully, including a frequency response comparison, and dispersion coefficients have been calculated by the moments method. The results are related to correlations previously advanced, including the use of an eddy diffusivity and of the Bodenstein number, and a more recent refined correlation allowing for density differences.
Lattice theory correlation for binary gas adsorption equilibria on molecular sieves
Authors: Lee A. K. K. 
Published: March 2009

AbstractA correlation method is presented for calculating the adsorption equilibria of a binary gaseous mixture and the total amount adsorbed, using pure‐component adsorption isotherms and a mixture parameter. The proposed method is based on the lattice theory of solutions and the concept of volume filling of microporous adsorbents. The method has been successfully applied to literature data for the adsorption of binary gas mixtures in molecular sieves type 5A, type 10X and H‐mordenite.
Biological wastewater treatment system design Part I. Optimal synthesis
Authors: Mishra Prakash N. , Fan Liang‐Tseng , Erickson Larry E. 
Published: March 2009

AbstractCommon practice for design of biological wastewater treatment systems involves evaluation of certain fixed structure systems at several alternative conditions. This study considered optimization of both the structure and the design of the system using the structural parameter system synthesis technique. The system was composed of a trickling filter, an activated sludge aeration vessel, and a secondary clarifier. Results of optimal synthesis indicated that the activated sludge system was the most cost effective system for the specific set of process parameters employed. The same conclusion was reached by optimizing several systems with different structures.
Biological Wastewater Treatment System Design Part II. Effect of Parameter Variations on Optimal Process System Structure and Design
Authors: Mishra Prakash N. , Fan Liang‐Tseng , Erickson Larry E. 
Published: March 2009

AbstractThis paper presents a study of the effects of parameter variations on optimal process system structures and designs for biological wastewater treatment systems. Results indicate that optimal system structure and design are sensitive to variations in the rate constants and feed concentration. Some of the process flowsheets deduced are innovative and have surprisingly low total costs. The process system structures and designs developed in this study merit consideration in future planning and design of wastewater treatment systems.
Kinetics and thermodynamics of oxygen chemisorption on an industrial vanadium oxide catalyst
Authors: Stanislaus A. , Evans M. J. B. , Mann R. F. 
Published: March 2009

AbstractThe chemisorption of oxygen on an industrial vanadium pentoxide/potassium sulphate catalyst has been studied in the temperature range 300‐353°C by a gravimetric technique. Agreement of equilibrium data with the Langmuir and Freudlich equations is not entirely satisfactory. The kinetic measurements suggest that at least two mechanisms are involved in oxygen chemisorption under certain conditions. At low coverage Langmuir or Elovich kinetics are followed reasonably closely although a pressure dependence is apparent suggesting dissociation into oxygen atoms before a final chemisorbed state is reached. Diffusion is suggested as the possible ratedetermining process at higher coverage. Langmuir analysis of the kinetics as equilibrium is approached shows that an unexpected pressure dependence also exists in this region.
A Generalized Correlation for Predicting Saturated Liquid Densities of Mixtures
Authors: Chiu C. ‐H. , Hsi C. , Ruether J. A. , Lu B. C. ‐Y. 
Published: March 2009

AbstractA generalized correlation for saturated liquid densities of pure compounds, based on the Guggenheim equation, has been extended for applications to mixtures. The method employs a mole‐average acentric factor and scaling volume, and a weighted average critical temperature for the mixture. The method was tested on twenty‐four binary and two ternary systems comprising hydrocarbons and non‐hydrocarbons. Overall average absolute deviation in predicted densities is less than two percent for a total of 1,096 data points.
Transient turbulent transport processes accompanied by first order chemical reactions or heat generations
Authors: Chung Benjamin T. F. , Wang Roger C. C. , Thomas Lindon C. 
Published: March 2009

AbstractA mathematical model of transient transport processes with homogeneous first‐order chemical reactions or heat generations is developed. The analytical expressions for the local transport coefficient and the mean potential profile are derived based on the film renewal and penetration concept. Solutions are presented graphically in terms of various dimensionless parameters. From the proposed formulations, the transient, reaction and surface resistance effects to the turbulent interphase heat or mass transfer can be analyzed.
A vortex model to relate eulerian and lagrangian “ turbulent” velocity fields
Authors: Base T. E. , Davies P. O. A. L. 
Published: March 2009

AbstractThe phenomenon of turbulent diffusion was studied by using computed models. Free pseudo‐turbulent fluid flow was simulated on a digital computer by ensembles of randomly positioned moving and interacting vortices to represent the eddy structure of the turbulence. A vortex model, which had statistical values corresponding to a measured real flow in an Eulerian frame of reference, was then obtained. By considering the motion of a particular vortex or a fluid particle in the computed pseudo‐turbulent flow it was possible to determine measurements in a Lagrangian frame of reference. Estimates of the mean square lateral excursions of a marked particle were obtained and finally the Lagrangian auto correlation was compared with the auto correlation in a moving frame of reference.
Effect of a variation in perforation size on performance of sieve tray absorbers
Authors: Pruden B. B. , Hayduk W. , Laudie H. 
Published: March 2009

AbstractA six inch diameter sieve plate absorption column was used to assess the effect of perforation size on the performance of sieve trays under otherwise identical conditions. Four separate test trays with equal gas flow areas but perforations of 1/8‐inch, 1/4‐inch, 1/2‐inch and 1‐inch respectively, were used with the liquid phase absorption‐controlled system of carbon dioxide — water at 77°F and approximately 830 mm. mercury.Comparisons of overall efficiencies indicated that the trays with 1‐inch diameter perforations had efficiencies similar to, or slightly lower than those of 1/8‐inch diameter. Concentration profiles within the froth were measured, with distinct profiles being observable in both the horizontal and vertical directions.This indicated that neither the plug flow nor the completely mixed models accurately described the actual transfer process. Accordingly, comparisons of volumetric mass transfer coefficients computed from both models were made. Comparison of volumetric mass transfer coefficients showed that for most gas and liquid flowrates the plates with 1‐inch perforations performed as well as plates with smaller holes. For this system it was concluded that trays with large holes would be much better suited to fouling services and, indeed, they would be only marginally less attractive than trays with smaller holes for all services.
A coupling model for the effect of ultrasonics on chemical reactions
Authors: Couppis Evis C. , Klinzing George E. 
Published: March 2009

AbstractIn an effort to obtain a macroscopic model predicting the effect of ultrasonics on chemical reactions, irreversible thermodynamic coupling between the chemical reaction rate and the trace of the viscous pressure tensor is investigated. The analytical predictions of the proposed model will be verified by the presentation of experimental data showing the effect of ultrasonics on the reaction rates near equilibrium conditions for the hydrolysis of methyl acetate.
Irradiation of butadiene‐styrene copolymers
Authors: Chau T. C. , Rudin Alfred 
Published: March 2009

AbstractPurified, gel free butadiene‐styrene copolymers were prepared by emulsion polymerization with butadiene contents of 80, 55 and 30 weight %. Radiation behavior of these materials at 30°C was independent of dose rate in the range 0.04‐0.46 Mrad/hour and the scission‐crosslinking ratio was about 0.40 for all copolymers and was independent of total dose. Extrapolated sol fractions at infinite dose, intrinsic viscosities of irradiated polymers and Mn in the pre‐gel region gave mutually consistent estimates of this ratio. G(crosslink) was 3.4. At the relatively low doses studied, intra‐molecular crosslinking was evident only with the high styrene content polymer. Active sites for intermolecular crosslinking are thought to be allylic to chain double bonds, whereas vinyl groupings may be involved in intramolecular crosslinking.