bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rates of dissolution of potash ore
Authors: Husband W. H. W. , Ozsahin Selim 
Published: March 2009

AbstractA long‐term program was undertaken in 1960 at the Saskatchewan Research Council to study the feasibility of solution mining potash ore. Appropriate scientific and engineering data for such a study were not available in the technical literature. Consequently laboratory studies were carried out to determine the dissolution rates of potash ore under conditions of natural convection mass transfer from vertical surfaces. The paper summarizes the methods used and the data obtained for the dissolution of potash ore. Both theory and data on the dissolution rates of soluble salts under natural convection conditions are inadequate for industrial purposes and areas of additional research are indicated.
Thermodynamic evaluation of the carbon‐hydrogen system at high temperatures
Authors: Blanchet J. L. , Parent J. R. , Covrtois P. A. 
Published: March 2009

AbstractA theoretical study of the C‐H system reveals that, at high temperatures, many polymeric species have to be taken into account. Free energy functions of the species involved have been calculated to permit the evaluation of the equilibrium compositions of the system in both the heterogeneous and homogeneous regions. Pressures ranging from 0.1 to 10 atm. and carbon to hydrogen ratios from 0.5 to 20 were investigated between 2,000 and 6,000°K.Since the reaction of carbon vapor with hydrogen is highly exothermic, a reaction scheme was also developed whereby the endothermic heat of cracking of various hydrocarbons could be balanced by the former reaction. Several conditions related to a global heat of reaction have been considered.
Local resistivity probe for study of point properties of gas‐liquid flows
Authors: Nassos G. P. , Bankoff S. G. 
Published: March 2009

AbstractIn this work a resistivity probe for local property measurements, developed originally(1, 2, 3) for (non‐wetting) mercury‐nitrogen flows, was adapted to a broader class of gas‐liquid flows, such as air‐water. To compensate for the non‐negligible dry‐out time of the probe in aqueous systems, a trigger circuit was installed to sense bubble arrival rapidly. Another problem which was solved was the greater tendency for bubbles in water, as compared to mercury, to deflect away from the probe. The probe signal is an instantaneous record of the arrival and departure of bubbles at any point in the flow, and hence is well‐adapted to auto and cross‐correlation measurements, as well as distribution function studies.
Air flow in a tube with a diverging inlet: II. Measurement and correlation of confirmed fully developed turbulent flow
Authors: Christiansen S. E. , Dallalan I. G. 
Published: March 2009

AbstractMean local velocities were measured in the section of a tube where turbulent flow was experimentally confirmed to be fully developed. Over Reynolds numbers from 9,000 to 56,0 00, the velocities correlated, using a logarithmic distribution, almost identically to those of Deissler. Because of the limited data for γ+< 26, no meaningful correlation near the wall was obtained.Using these data as a basis, a comparison of the various correlations for fully developed turbulent flow in the core region was performed. Although measurements in the laminar sublayers were limited, some discussion of correlations applicable over the entire cross‐section of the tube is included.Pai's equation, valid from the wall to the center‐line, was found to correlate all of the data best for the several approaches tested. In the turbulent core, the improved universal velocity distribution correlation suggested by Bogue but in simplified form, correlated the data equally well. Using the method of Wasan et al, this logarithmic distribution could be joined without a discontinuity to other suitable correlaions valid near the wall.
Laminar flow in axisymmetric conduits by a rational approach
Authors: Shih F. S. 
Published: March 2009

AbstractNumerical and closed‐form solutions to laminar flow in regular polygonal conduits, star‐shaped conduits, and rectangular conduits are presented. Results by the present approach are shown to be more accurate and the computation to require less effort than conventional methods. The formal finite‐series solutions obtained through the present approach lend themselves to parametrization and to a judicious choice of computational schemes. In addition both analytical and numerical procedures yield exact solutions to flow in an equilateral and in an elliptic conduit. The present approach proves to be advantageous in its accuracy, generality, and simplicity.
A kinetic study of catalytic butane dehydrogenation
Authors: Noda S. , Hvdgins R. R. , Silveston P. L. 
Published: March 2009

AbstractA study was made of the dehydrogenation of n‐butane over a commercial chromia‐alumina catalyst. Dehydrogenation runs were performed at 500°C. and space velocity of 34,000 hr−1 over a range of butane partial pressures from 0.06 to 1.80 atm. Conversions were differential, averaging about 3% (with a maximum of 6% ) of the input butane.Reaction was found to be 0.75 order in butane partial pressure. Thermodynamic equilibrium was attained among the products, which were 1‐butene, cis‐2‐butene, and trans‐2‐butene.The method of Yang and Hougen showed dehydrogenation to be surface reaction controlled at a confidence level of 91%. This conclusion agrees with that of a previous study by Dodd and Watson.
Direct contact heat: Transfer with change of phase: Evaporation rates in vacuum freezers
Authors: Shiloh K. , Sideman S. 
Published: March 2009

AbstractThe basic factors affecting the rate of evaporation from salt‐water ice slurries in a vacuum freezer were investigated. The interfacial liquid‐phase thermal resistance is governing the evaporation process. The heat transfer coefficient is independent of the temperature driving force up to about 0.7°C., and is strongly affected by mixing and ice concentration. Vapor bubbles, internally generated or entrained, which appear at higher ΔT's increase the dependency of the transfer coefficient on ΔT and decrease the dependency on the mixing rates. Interfacial break‐up greatly increases the transfer rates. The transfer coefficients increase with ice concentration, up to 2 to 5% ice fraction, depending on the mixing rate, then decrease with increased ice fraction due to increased viscosity. Theoretical considerations substantiate the experimental results.
Reactor optimisation problems for reversible exothermic reactions
Authors: Dyson D. C. , Horn F. J. M. , Jackson R. , Schlesinger C. B. 
Published: March 2009

AbstractOptimization of tubular reactors in which the desired reaction is exothermic and reversible is considered. For the cases where there are no side reactions and there is no decay of catalyst various types of temperature control are investigated. The remaining cases considered are a) stable catalyst, irreversible decay of product and b) decaying catalyst, stable product. In each of these cases perfect indirect temperature control is treated. Particular attention is given to devising numerical methods which take advantage of the structure of the problem in question and to convenient representation of data.
Adaptation of the two‐derivative method of optimisation in cases of non‐convergence
Authors: Methot J. C. , Cholette A. 
Published: March 2009

AbstractProblems of optimization are often solved readily by means of the Two‐Derivative Method but suitable adaptation is required at times to bring about convergence, as is sometimes the case in the optimization of stage processes.The nature of the corrective action can be suggested by the physical limitations of the particular problem investigated or by the peculiarities of the function to be optimized. Different adaptation techniques are examplified by various problems: minimum energy requirements for IV compressors in series; optimum solvent distribution between N extractors in series when cross flow takes place, whether the equilibrium relationship is represented by a straight line or by a curve; optimum number of stages in counter‐current extraction, without the need for the construction of a special graph with two families of superposed contour lines.
Solving complex chemical equilibria by a method of nested iterations
Authors: Storey S. H. , Van Zeggeren F. 
Published: March 2009

AbstractThe equilibrium composition of a mixture of molecular species can be obtained by finding the solution of a set of simultaneous non‐linear equations relating the concentrations of these species. Atom balance equations, wherein the species concentrations are related to each other through chemical equilibrium constants, form a many‐variable set of simultaneous non‐linear equations. It is shown how many‐variable problems of this type can be treated as a nested set of single‐variable equations. This treatment allows the use of recent, powerful methods for forcing convergence in single‐variable iterations. The method developed does not require explicit matrix inversion. It is fast and suitable for a small computer. The method has been found particularly useful for routine computations. Up to two non‐gaseous species can conveniently be included. An example is given of the use of the method.
The kinetics and mechanism of the chloride‐chlorate reaction
Authors: Hong C. C. , Lenzi F. , Rapson W. H. 
Published: March 2009

AbstractThe kinetics of the reaction

have been studied at 25°C. in strong acid solution; the effects of acidity, chloride, chlorate and chlorine are reported.A mechanism is postulated to interpret the peculiar features of this reaction as well as the stoichiometry and some of the kinetics of the parallel reaction

The mechanism involves HClO2 and HOCl as intermediates

General rate expressions are derived for the formation of chlorine dioxide and chlorine, and the individual rate constants are calculated. An expression is obtained for the relationship between the ratio of chlorine dioxide to chlorine produced and the ratio of chlorate to chloride.
Vapor phase reactions of graphite with light hydrocarbons
Authors: Blanchet J. L. , Parent J. R. 
Published: March 2009

AbstractThe pyrolysis of ethane and propane has been performed in the presence of carbon vapor at temperatures between 2,000°K and 5,000°K. This high energy environment is obtained by an electric arc struck between two graphite electrodes. The quenched gases are analyzed by gas chromatography.The major reaction products are acetylene and hydrogen. C2H2 yields are a function of the C/H2, ratio, the power input, the reaction temperature and the total pressure.Power levels between 10 and 50 kw. and gas flow rates of 1.5 to 20 liters per minute have been used. The electric arc process of hydrocarbon cracking is compared with conventional methods of acetylene production.
The longitudinal mixing of liquids in bends
Authors: Aunicky Z. 
Published: March 2009

AbstractThe longitudinal mixing of liquids flowing through straight pipes may be characterized by the coefficient of longitudinal dispersion K. In the case of pipings equipped with bends, the value of K must be extended by ΔK expressing the more intense longitudinal mixing in bend areas. Physically, the value of ΔK is determined by the secondary flow in pipe bends.The dependence of ΔK upon the Reynolds number NR = 15 180‐73 180/, the bend length /α = 30°.90°/ and the proportional bend curvature /R/D = 2‐6/ has been measured on a 50,8 mm ‐ diameter pipe. These dependences are expressed by empirical equations. Each of these partial results is further discussed from the view of relationships valid for secondary flows. The individual values of dependence are summarized in a final equation expressing the simultaneous effect of each observed variable upon the value of ΔK, i. e.
Gamma‐initiated chlorination of methane
Authors: Werezak G. N. , Hodgins J. W. 
Published: March 2009

AbstractGamma radiation has been used to initiate the gas phase reaction between chlorine and methane. The products consist of hydrogen chloride, and the four chlorinated methanes, in yields depending on the experimental conditions. Experiments were conducted over a range of temperatures, pressures, concentrations and absorbed doses. G values as high as 1.2 × 106 were found, indicating the formation of a chain reacting system. Two hypothetical reactor models were used to obtain an estimate of the energy cost of the process. On the basis of the reactor models studied, a one‐pass gamma reactor appears uneconomical for the production of carbon tetrachloride, but the energy cost for methyl chloride production is less than one percent of the product value.
A study of stripping uranium complex from an amine extract with aqueous salt solutions
Authors: Jickling R. S. , Diez Gerhard , Van Cleave A. B. , Decovrsey W. J. 
Published: March 2009

AbstractThe organic phase produced by extraction of a uranium leach liquor with Amberlite LA‐2 in kerosene was stripped of uranium in laboratory tests with solutions of NaCl and H2SO4 or solutions of Na2SO4. It was found that NaCI‐H2SO4 stripping reduced considerably the effectiveness of the solvent for subsequent extraction, whereas Na2SO4 stripped the uranium content without any deleterious effect. Optimum Na2SO4 concentration and pH for stripping were determined. Phase separation time and entrainment losses appear satisfactory.
Effect of various parameters on the level of mixing in continuous flow systems
Authors: Cloutier Leonce , Cholette A. 
Published: March 2009

AbstractVariations of the level of mixing in a flow system have been investigated as a function of the following parameters: diameter, shape and speed of the agitator, feed rate and position of the feed inlet.At agitator speeds inferior to a critical value, a minimum level of mixing is observed which depends on the position of the feed inlet. At speeds superior to the critical value, the level of mixing increases linearly with agitator speed, at a given feed rate, until conditions of perfect mixing are reached. The critical agitator speed and the position of each straight line depend on the agitator size. A modified Reynolds number makes possible a more general correlation.At a given agitator speed, superior to the critical value, the level of mixing decreases as the feed rate increases, due to the smaller amount of energy imparted by the agitator per unit mass of feed. The effect of agitator shape on the level of mixing is rather pronounced as it affects the flow patterns inside the reservoir.
Effet du diamètre de l'agitateur et de la largeur des chicanes sur le niveau d'agitation en régime continu et sur la puissance dissipée
Authors: Garceau J. , Cloutier Leonce , Cholette A. 
Published: March 2009

AbstractLe systéme étudié consiste en un réservoir cylindrique vertical muni d'un agitateur coaxial à turbine et de chicanes. L'entrée de l'alimentation et la sortie de l'effluent se trouvent dans l'axe du réservoir, la première sous l'agitateur et l'autre en surface.On a utilisé un modèle proposé par Cholette et Cloutier pour caractériser les paramètres de l'agitation. A une vitesse donnée de l'agitateur, la présence de chicanes a pour effet de diminuer le niveau d'agitation. Cette diminution est une fonction complexe de la largeur des chicanes. La présence de chicanes entraǐne également une diminution du court‐circuit.Le couple varie avec le niveau d'agitation; il augmente en présence de chicanes et encore plus pour de grands diamètres de l'agitateur.Les auteurs proposent une représentation des différents circuits internes qui permettent d'expliquer les résultats expérimentaux.
Velocity profiles and pumping capacities for turbine type impellers
Authors: Cooper R. G. , Wolf D. 
Published: March 2009

AbstractVelocity and angle profiles emanated by turbine type impellers were measured in both air and water using a hot wire anemometer probe and two and three dimensional pitot tubes. Pumping capacities were then calculated from the velocity data. The effect of the rotational speed and the dimensions of the turbine was investigated.
Thermal conductivity of simple gases at normal pressures
Authors: Roy Dipak , Thodos George 
Published: March 2009

AbstractThermal conductivity measurements available in the literature for simple gases at normal pressures (approximately 1 atmosphere) were used to obtain the productk*λ, where the parameter, λ =M1/2Tc1/6/Pc2/3. Separate relationships betweenk*λ andTRresulted for monatomic, diatomic and triatomic gases.The relationships for monatomic gases can be expressed as followsFor the diatomic and triatomic gases, linear relationships resulted, when at the same reduced temperatures, theirk*λ values were plotted against (k*λ)mon log‐log coordinates. These relationships can be expressed in equation form as followsandThermal conductivities calculated with these relationships have been compared with experimental values and produce an average deviation of 2.8% for the monatomic gases (219 points), 4.3% for the diatomic gases (282 points) and 4.6% for the triatomic gases (242 points).In this treatment, helium and hydrogen do not follow the general pattern and consequently these substances have been treated separately.
Nonuniform initiation of photoreactions II. Diffusion of reactive intermediates
Authors: Hill F. B. , Reiss N. 
Published: March 2009

AbstractThe influence of spatially nonuniform initiation is investigated for a class of photoreactions in which diffusion of intermediates is important. The investigation is centered on a differential equation for reaction and diffusion of reactive intermediates. The circumstances are set forth under which the equation is valid for several kinetically similar reaction types. A solution is obtained for Lambert's law attenuation. The characteristics of this solution and the solution obtained by Noyes for linear attenuation are discussed. The practical consequences of these solutions are shown through illustrative calculations based on the photochlorination of tetrachloroethylene.
An equation of state for liquids
Authors: Chaudhari P. Mitra , Mathvr G. P. , Stager R. A. 
Published: March 2009

AbstractA comparatively simple and accurate equation of state has been developed for the liquid state. The proposed equation has the form

where K and q are constants dependent on temperature. The equation is tested for validity against P‐V‐T data for aldehydes obtained in the course of this investigation. Literature data on alkanes, alcohols, and water were also utilized to confirm the validity of the equation. A critical comparison of the proposed equation with the Hudleston equation reveals the former to yield more satisfactory prediction of P‐V‐T behavior of liquids.
The pipeline flow of paste slugs: Part II. Pressure gradients and velocities of trains of slugs
Authors: Brown R. A. S. , Jensen E. J. 
Published: March 2009

AbstractPrevious studies of the pipeline movement of single paste slugs of coal have been extended to determine the velocities of, and the pressure gradients along, trains of slugs. The measurements were taken in a 70‐foot long, closed‐loop line made from 0.95‐inch bore, rigid plastic tubing. Flow in the line could be switched to maintain continuous movement of a train of slugs.Tests were made with slugs of 80:20 (w/w) coal‐water paste which was extruded through a 0.775‐inch die and also with slugs which were stabilized by the addition of agar to the water used for making the slugs. Slugs made from coal and agar solution were formed in cylindrical molds having diameters of 0.567, 0.661 and 0.756 inches and were intended to show more clearly the influence of slug diameter on the behavior of the trains. Individual slugs were five inches in length and were formed into trains with lengths of up to fifteen feet for the tests. The oil used as carrier fluid was a light mineral oil (μ = 5.92 cp,σ = 0.826 at 70°F.), which was circulated through the pipeline loop at velocities ranging from 1.0 to 10.0 ft./sec.
The simulation of an existing ethane/dehydrogenation reactor
Authors: Petryschuk W. F. , Johnson A. I. 
Published: March 2009

AbstractThis paper is concerned with the mathematical representation of an existing box‐type furnace for the thermal dehydrogenation of ethane. The furnace is composed of a preheating convection section and a radiant heated section. The two models considering (i) the tube‐side calculation and (ii) the radiant heat transfer in the combustion chamber are independent of each other.A study is made of the effects of pressure, heat flux level and “steam/hydrocarbon” ratio on the effluent composition. A significant improvement in reactor operation if a more uniform heat flux could be achieved is predicted.From the radiant heat transfer computations an unexpected variation in flame temperature in the furnace under study was detected.
The kinetics of oxidation of sodium sulphite
Authors: Srivastava R. D. , Mcmillan A. F. , Harris I. J. 
Published: March 2009

AbstractThe kinetics of the reaction of oxygen with sodium sulphite in aqueous solution without and with a catalyst of cobaltous sulphate have been studied by a flow thermal method.The rate of reaction of oxygen and sodium sulphite was found to be first‐order with respect to oxygen and variable order with respect to sulphite, and the promoting effect of cobaltous catalyst was proportional to its concentration. A reaction mechanism has been proposed and a rate expression derived which is in good agreement with the experimental data.
Effects of turbulence on particulate heat and mass transfer
Authors: Clamen A. , Gauvin W. H. 
Published: March 2009

AbstractThis paper reviews a number of experimental studies concerned with the influence of turbulence on heat and mass transfer from a particle in a fluid medium. Heat and mass transfer rates, as affected by free‐stream turbulence, undoubtedly reflect changes in the ambient flow structure around a body. Attempts have been made, therefore, to relate the established effects of turbulence on the various parts of the flow field around a particle to the variations in heat and mass transfer rates observed for investigations conducted under different conditions. A review has also been made of the effects of periodic oscillations on heat and mass transfer rates in an attempt to provide greater insight into the more complex effects of turbulence.
Solution of reaction and heat flow problems by nonlinear estimation
Authors: Surkan A. J. , Wu C. L. 
Published: March 2009

AbstractBefore the advent of nonlinear optimization algorithms, the solution of chemical reaction or heat transfer equations was attempted primarily by trial and error or linear approximation methods. In the method illustrated by the two examples in this paper, any set of nonlinear equations for a chemical or physical process are replaced by a single equation. The variables of interest are in the resulting functional equation treated as parameters whose optimum values are determined by a nonlinear estimation technique. These values are considered as nonlinear regression coefficients which are simultaneously adjusted by an optimization algorithm. The method gives an estimate of the standard deviation in the determination of the value of each variable and provides information concerning the errors associated with their interaction or pairwise correlations. Validity of the results is confirmed by comparison with solutions independently obtained through a matrix technique developed by Wu (1). For each of the examples the magnitude of computed residual is provided as a measure of the precision of the solution set. The general method is applicable to a very wide class of physical and chemical problems described by one or more nonlinear equations.