bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the thermodynamics of concentrated strong electrolytes aqueous solutions the system NaNO3—NaCl—H2O
Authors: Correa H. A. , Vera J. H. 
Published: March 2009

AbstractA simple analytical function is proposed for the calculation of molar excess Gibbs energy of binary solutions of strong electrolytes in water. Empirical parameters can be easily determined from experimental data reported in the literature.The treatment is extended to ternary solutions and to solid liquid equilibria using an empirical equation. Absence of solid solutions is assumed.The correlations are applied to the common ion ternary system NaNO3‐NaCl‐H2O in the temperature range from 0 to 100°C.Predictions of activity coefficients of the binary systems and saturation curves of the ternary system are in good agreement with experimental data.
Identification and direct digital stochastic control of a continuous stirred tank process
Authors: Hong Huynh Man , Macgregor John F. 
Published: March 2009

AbstractSeveral aspects associated with the identification and direct digital stochastic control of a steam‐jacketed continuous stirred tank process are investigated. Using data collected under closed‐loop conditions by an on‐line mini‐computer, statistical modelling procedures are used to identify, fit and check a discrete dynamic‐stochastic model for the process and its disturbances. Based on these models an optimal stochastic feedback controller is implemented using the minicomputer. A practical modification of this optimal controller is suggested and the modified stochastic controller is implemented and its performance is evaluated.
Optimization of multistage recycle systems by direct search
Authors: Luus Rein 
Published: March 2009

AbstractOptimal operation of chemical systems with recycle is considered. An optimization procedure, whereby the control variables are obtained by direct search, is developed.Suitability of this method for optimizing chemical engineering systems with recycle is tested by considering three systems of different complexity. Results close to the optimum were obtained in each case. For complex systems, however, care must be taken to ensure that global and not local optimum is obtained.Due to the ease of formulation and of programming, the proposed method provides an attractive alternative to the combined use of the gradient method and Lagrange multipliers.
The rate of mass transfer at a rotating cylindrical electrode with wiper blades
Authors: Nadebaum P. R. , Fahidy T. Z. 
Published: March 2009

AbstractA theoretical analysis of mass transfer at a rotating cylindrical electrode with wiper blades yields the dimensionless equation

where w is the number of the symmetrically located wiper blades, d is the wiper blade thickness and R1 is the radius of the wiped electrode. NuR, ReR and Sc are defined in terms of the cell and electrolyte parameters. Experimental evidence via the reduction of oxygen and ferrocyanide ions indicates that mass transfer rates can thus be predicted at no more than ±5% inaccuracy for Sc > 200. The two‐wiper blade system is shown to effect an increase in mass transfer rates by a factor of 7–8 with respect to a rotating cylindrical electrode without wiper blades.
Activation de la tourbe de sphaigne par le dioxyde de carbone et agglomération du charbon actif produit
Authors: Son P. N. , Khanh P. V. , Chornet E. 
Published: March 2009

AbstractThe physical activation of peat moss using CO2 has been investigated with respect to the operational variables and the characteristics of the active carbon produced. Peat coke is produced during carbonisation with a 30% yield. The activated carbon accounts for 25% of the initial air dried peat moss.Analysis of the active carbon has revealed a surface area up to 600 m2/g and a chemical reactivity similar to commercial active carbon as measured by the iodine, phenazone and phenol indexes.The active carbon thus produced is a powdered material, with a weak abrasive resistance. Agglomeration of the carbon and subsequent pelletization has been done with ammonium ligno‐sulfonate, water, and the application of pressure. Resistant pellets can be obtained using 15–20% lignosulfonate and 3000 psi.
Thorium as a nuclear fuel for CANDU reactors
Authors: Banerjee S. , Critoph E. , Hart R. G. 
Published: March 2009

AbstractThe reasons for the attractiveness of thorium as a fuel for CANDU reactors are discussed. By the use of thorium fuels it is shown that the amount of energy that can be extracted from nuclear fuel resources can be increased substantially. Cumulative savings in nuclear fuel requirements are estimated for a number of situations.The thorium fuel cycle is shown to be relatively insensitive to the cost of natural resources. The conditions under which fuelling costs for the thorium cycle will become competitive with the present natural uranium fuel cycle are discussed.
Règies de construction et d'extrapolation des réacteurs auto‐agités par jets gazeux
Authors: David R. , Matras D. 
Published: March 2009

AbstractAn analysis is made of the agitation mechanism in a spherical reactor which is self‐stirred by means of gas jets; it is made on the double assumption of an internal recycling and of a turbulent free jet.Extrapolation laws have been developed and verified experimentallly by means of the residence time distribution in several reactors of volumes varying between 501 and several cubic centimeters, the passage times varying from 0.6 to 7.5 seconds: the experiments involved several gases and different temperatures.
Vapor liquid equilibrium constants through a non‐equation of state approach: Methane‐free aliphatic binary systems
Authors: Hsiung Thomas H. , Thodos George 
Published: March 2009

AbstractUsing vapor liquid equilibrium measurements available in the literature for the three binaries of the system ethane—n‐butane—n‐heptane, correlations have been developed that predict K‐constants for other aliphatic binary mixtures, not containing methane. This approach does not involve the use of an equation of state, but utilizes fundamental properties associated with the pure state components and the critical pressure of the mixture.This method produces for seven additional binary systems, K‐values that are in good agreement with experimental measurements, and particularly in the vicinity of the critical point.
An improved group solution model for the prediction of excess free energies of liquid mixtures
Authors: Ronc M. , Ratcliff G. A. 
Published: March 2009

AbstractAn improved analytical group solution model has been developed and applied to mixtures containing the groups methylene and hydroxyl. The new model predicts molecular activity coefficients for alcohol/n‐alkane and alcohol/water systems with an accuracy of about 5%. Predictions are equally good for systems of alcohols and n‐alkanes of the same chain length; earlier models give poor predictions for these newly‐measured systems.
Uni‐directional spreading of one liquid on the surface of another
Authors: Huh C. , Inoue M. , Mason S. G. 
Published: March 2009

AbstractThe spreading rate of a thin film of a liquid on the horizontal surface of an immiscible liquid substrate is calculated by an approximate quasi‐steady analysis. Spreading is assumed to be driven by the combination of gravity and interfacial forces. Dimetryl siloxane fluids of various viscosities were permitted to spread uni‐directionally on the surface of water in a rectangular channel. The measured rates were in reasonably good agreement with the theoretical values.
Relationship between capsule pulling force and pressure gradient in a pipe
Authors: Kruyer Jan , Snyder William T. 
Published: March 2009

AbstractA method is presented for predicting the pressure gradient required to transport a cylindrical capsule through a liquid‐filled pipeline. It is based upon a coefficient of lubricated friction which is obtained experimentally by pulling a capsule by a string through the liquid‐filled pipe. A simplified method for measuring this coefficient and relating it to the capsule pressure gradient is proposed.
The kinetics and mechanism of the oxidation of carbon monoxide over an industrial vanadium oxide catalyst
Authors: Mann R. F. , Tycholiz D. , Stanislaus A. 
Published: March 2009

AbstractThe rate of catalytic oxidation of carbon monoxide was studied in a fixed bed reactor over the following range of conditions: 325 to 396°C, 0.11 to 1.75 mole % oxygen, 9.50 to 10.20 mole % carbon monoxide. Oxygen was the limiting component, most of the runs were taken to greater than 10% oxygen conversions, and therefore an integral approach was taken in the data analysis. The catalyst was vanadium oxide/potassium sulfate on silica, an industrial preparation which had been used in previous kinetic studies.The data were correlated successfully by the steady state adsorption model with Arrhenius activation energies of 22.1 k.cal/g. mole for the oxygen chemisorption step and 18.0 k.cal/g. mole for the reaction step.The rate constants obtained provide further support for the steady state adsorption model, previously used to evaluate the oxidation kinetics of naphthalene, toluene, benzene and orthoxylene on the same catalyst. The integrated rate equation appears to well describe the relationship between the various parameters with the conversion of the limiting component varying from less than 5% to over 50%.A brief comparison is reported between the steady state adsorption model and the more complex triangular mechanism postulated by Hirota and co‐workers.
Elimination of initial conditions in linear dynamic batch process identification by least squares
Authors: Xuyen V. T. , Svrcek W. Y. 
Published: March 2009

AbstractThe requirement of data from many batch runs and the need to estimate initial conditions for each batch complicate dynamic batch process identification. However, when the model used to represent the dynamics is linear in the state vector, utilization of Lawton's and Sylvestre's idea avoids direct‐estimation of the initial conditions for each batch. This simplification permits an approximate on‐line identification procedure to be developed to update the model as data from each new batch are received.
Laminar transient flow in pipes
Authors: Masliyah J. H. , Shook C. A. 
Published: March 2009

AbstractThe effects of fluid viscosity, pipe length, radius and pressure wave celerity are examined by solving the equations of fluid motion numerically for impulsively started flows. Velocities are obtained in terms of axial and radial positions and time. Pressures are obtained as a function of axial position and time using an averaging process. The dimensionless group \documentclass{article}\pagestyle{empty}\begin{document}$\frac{{\rho a{\rm R}^2}}{{\mu {\rm L}}}$\end{document} is shown to determine the development of these profiles.At low values of this group, a significant axial variation in the velocity profiles occurs. The pressure fluctuations accompanying startup however are progressiveely more damped as this group decreases. Such fluctuations are shown theoretically and experimentally to disappear when the aforementioned group falls to about 1.6. The numerical method used is capable of being applied to other transient pipe flows.
Behavior of macromolecules in dilute solutions: II—On the axial dispersion coefficient
Authors: Chen H. R. , Blanchard L. P. 
Published: March 2009

AbstractUsing pulse‐input technique, axial dispersion coefficients were determined for polystyrene in tetrahydrofuran, in toluene and in a toluene/methanol mixture flowing in a long capillary tube under conditions such that the Reynolds number was less than 500. Low polydispersity polystyrene materials with nominal molecular weights ranging from 900 to 1.8 × 106 were used. For the system studied and for fixed Reynolds numbers, the coefficient, on log‐log scales, was found to be a linear function of the product of the intrinsic viscosity and the molecular weight. An empirical equation relating this coefficient to the Reynolds number and to [η]M was obtained. This equation predicted results which agreed well with experimentally determined values.
The vaporization of small binary drops on a flat plate at maximum heat flux
Authors: Mann R. F. , Walker W. W. 
Published: March 2009

AbstractThe vaporization times of small (12 mg.) drops of a binary liquid on a flat plate were measured in the maximum (critical) heat flux region of boiling heat transfer. The binary system studied was water‐1‐pentanol, the mixture previously shown by other workers to exhibit the most pronounced concentration effect on critical heat flux. Evaporation curves are reported in the critical region for pure water, pure pentanol and a number of mixtures in the concentration range 1.0 to 2.5 weight % pentanol in water.It was confirmed that drop lifetimes can be obtained in the critical heat flux region by comparatively simple techniques and that there is a concentration effect on drop lifetime that is very similar to that observed during critical heat flux boiling studies. A minimum drop lifetime is observed at 1.8 weight % pentanol in water, the same concentration at which maximum critical heat fluxes were obtained in pool boiling studies at one atmosphere by S. J. D. Van Stralen and co‐workers.
Mass transfer from cylinders at various orientations to flowing gas streams
Authors: Willins Richard E. , Griskey Richard G. 
Published: March 2009

AbstractThe effects of angle of cylinder orientation and cylinder length on mass transfer rates were studied for Reynolds numbers ranging from 6,000 to 18,000. Orientations (ϕ) varied from 0° to 90° for cylinders whose L/D's ranged from 5.26 to 21.04.The relation jm = m(N Re)n fit the data for a given orientation and L/D. Both jm and NNu, data compared favorably to literature values for transverse and parallel flow. Sherwood numbers were shown to be [1] a function of (N Re × sin ϕ) [2] to correlate with Consin's “cosine law” and [3] to be a function of L and ϕ.Peak mass transfer occurred between 45° and 75°.
Optimum attenuation of inlet fluctuations in a flow system for imperfectly mixed tanks in series
Authors: van Bang Vo , Chiang David , Cholette A. 
Published: March 2009

AbstractThe damping effect of a cascade of identical imperfectly mixed reservoirs on fluctuations in the feed is presented as a function of the various parameters of the flow system.For a sudden and lasting change in concentration of the feed, the optimum conditions are presented such that the rate of change in the outlet stream be kept to a minimum during the transition period.In the case of a single square wave disturbance, it is shown how the maximum upset in the outlet stream is related to the characteristics of the system.The relative performance of various systems is shown graphically, based on the model of partial mixing and short‐circuit for each of the tanks in a cascade.When little or no channeling is present, the best attenuation for the two cases considered is often obtained by using a cascade of only two reservoirs. As the degree of channeling increases, more reservoirs are required for an optimum performance.
Transesterification of dmt with ethylene glycol catalyzed by amberlyst 15
Authors: Yamanis John , Adelman Maurice 
Published: March 2009

AbstractThe catalytic effects of the macroreticular cation exchange resin Amberlyst 15 (H+) on the transesterification of dimethyl terepbthalate with ethylene glycol have been investigated in a batch reactor and at the temperature of 146°C with the aid of extensive chemical analysis. The resin exhibited significant intraparticle diffusion effects for the disappearance of dimethyl terephthalate and promoted the dehydration and subsequent etherification and polymerization reactions of ethylene glycol to a very significant extent. The side reactions of ethylene glycol rendered the transesterification process in the presence of Amberlyst 15 (H+) inefficient.
The effects of an electrostatic field and air stream on water jet break‐up length
Authors: Garmendia L. A. , Smith I. K. 
Published: March 2009

AbstractAn experimental study of the break‐up length of a circular section liquid jet subject to the combined action of a coaxial airstream and an electrostatic field is reported. A high speed photographic technique has been employed and the results have been correlated empirically by the following dimensionless equation:

where “b” and “k” are functions of Reynolds number.
The behaviour of the dispersed phase in liquid‐liquid cocurrent flow through a packed bed
Authors: Duffy John P. , Kadlec Robert H. 
Published: March 2009

AbstractThe drop size distributions produced by the cocurrent flow of kerosene dispersed in water through a vertical column packed with spheres have been measured at different levels of flow rate, volume fraction dispersed phase, packing diameter and height of packed bed. The drop size measurements were made by isolating and photographing a portion of the dispersion as it emerged from the packing. The Sauter mean diameter is predicted by:

where C is a constant, f(ϕ) is the phase fraction effect, ∈ is the power input per unit volume, τ is the residence time and dp is the packing diameter.
Effect of pretreatment and adsorption conditions on gas adsorption by supported metal catalysts
Authors: Flynn Peter C. , Wanke Sieghard E. 
Published: March 2009

AbstractThe influence of pretreatment and adsorption conditions on the adsorption of oxygen and hydrogen on supported Pt and Rh catalysts has been studied. It has been found that reduction conditions (temperature and time) and subsequent out gassing conditions influence the amount of gas adsorbed. Oxygen and hydrogen uptakes measured in a static system were significantly different than those measured in a dynamic system. Reproducible adsorption uptakes can be obtained by careful control of pretreatment and adsorption conditions.
The mechanism of the adsorption of ethyl xanthate ion on galena (II)
Authors: Wells P. F. , Van Cleave A. B. 
Published: March 2009

AbstractStudies of the adsorption of 35S labelled ethyl xanthate ion and of 35S labelled diethyl dixanthogen show that both species are competitively chemisorbed to an approximately equal extent on a galena surface, but that ethyl xanthate ion is oxidised to a species which is physically adsorbed, while diethyl dixanthogen is reduced to ethyl xanthate ion which is partially desorbed. It is suggested that galena surfaces are sufficiently heterogenous that oxidative chemisorption and oxidation of ethyl xanthate ion can take place on the anodic parts of the surface while diethyl dixanthogen can be reductively chemisorbed or completely reduced on the cathodic areas.The relationship of these processes to the normal flotation of galena is discussed.
High temperature propane cracking in an argon plasma with the presence of aluminum vapor and tungsten particles
Authors: Meubus Paul 
Published: March 2009

AbstractPropane cracking has been carried out in argon, in the presence of either aluminum or tungsten vapor as well as condensed particles of the same metals. The cracking reaction was taking place in the homogeneous phase of a carbon/hydrogen system, yielding mainly acetylene and hydrogen. Propane/argon molar ratios of 1.5 and 6.0% were used, associated with aluminum or tungsten, in concentrations ranging from 0.02 to 0.75%. Maximum acetylene yields up to 93% were obtained in the presence of metal vapor, against a maximum attainable value of around 67% without metal vapor in the plasma. Also, the optimum temperature required for maximum conversion markedly decreased in the presence of metal vapor.Maximum conversion values occurring around 4,000°K in the presence of aluminum or tungsten, associated with similar crystalline structures related to these metals, lead to the assumption of a solid catalytic effect promoted by condensed metal vapor in the quenching phase. Also, a strong spectroscopic emission at 3,092.7A for aluminum excited atoms could explain the high conversion obtained around 5,000°K when smaller propane/argon ratios are used.
On the dehydrogenation reaction of n‐butane with the deactivation of alumina‐chromia catalyst
Authors: Uchida S. , Osuda S. , Shindo M. 
Published: March 2009

AbstractAn experimental study on the dehydrogenation reaction of n‐butane to n‐butene with alumina‐chromia catalyst has been performed using a differential reactor. N‐butene produced and coke deposit on the catalyst were continuously measured and the mechanisms of the reactions of dehydrogenation of n‐butane and coke deposition have been investigated.According to the assumptions that there are two types of active sites effective for the dehydrogenation reaction, Lewis acid site and Brönsted acid site, and that the coke deposition takes place only at Lewis acid sites, the rate equations of these reactions have been obtained.
The application of spectral analysis in monitoring extraction column behavior
Authors: Strand Michael J. , Garlid Kermit L. 
Published: March 2009

AbstractCorrelation and spectral functions resulting from the analysis of organic phase volume fraction measurements on a pulsed, sieve‐plate solvent extraction column are presented, and some of the changes that occur as the flow characteristics of the column change are shown. Spectral functions reveal the shifts in operation more directly than do the correlation functions. General trends of both correlation and spectral functions with changing flow characteristics are discussed. Spectral density ratios which reflect the power density in the low frequency bandwidth from 0 to 0.1 Hz relative to that at the pulsing frequency are defined. These ratios are shown to correlate directly with the mode of column operation and are especially sensitive to incipient flooding. Hard limiting of the data prior to spectral analysis is shown to have little detrimental effect on the calculated functions of interest.
Holdup dynamics of a single stage gas‐solid fluidized bed adsorber
Authors: Papadatos K. , Svrcek W. Y. , Bergougnou M. A. 
Published: March 2009

AbstractThe dynamics of the tray solids holdup for a single stage gas‐solid fluidized bed adsorber with a downcomer was studied. The method chosen was based on a material balance of the form \documentclass{article}\pagestyle{empty}\begin{document}$ L_i - L = \frac{{dH}}{{dt}} $\end{document} and an experimental relationship of the holdup H to the solids flowrate L. When the column to weir diameter ratio was 4.4 and 8.8 this relationship was of the linear form H = Hs + τL implying first order dynamics with time constant equal to τ. The time constant was not affected by the superficial gas velocity but it was shown to be a linear function of the weir height. The weir diameter and the particle density of the solids also showed an effect. Specifically, τ increased with the particle density and with decreasing weir diameter. When the column to weir diameter ratio was increased to 13.5 the holdup to solids flowrate relationship was non‐linear.
Non‐foaming adsorptive bubble separation of DBSNa and foam separation of cadmium
Authors: Kubota Katsuyuki 
Published: March 2009

AbstractIn recent years, the use of synthetic surfactants, “detergents”, has brought about extensive foaming on rivers and during sewage treatment. Many methods have already been proposed on the removal of surfactants from waste water by the physico‐chemical approach. The present paper however deals with the removal of the anionic surfactant, dodeclbenzensulfonate (DBSNa, M.W. = 348.48) form aqueous solution by the bubble separation technique, which has already been investigated in model systems by some workers.(1–10) This paper is also devoted in part to the removal of cationic metallic ion(12–17) from its dilute solution by suing a DBSNa collector in a stable foaming region, (pH = 6.3) similar treatments have employed the precipitate floatation mehtods.(18,19)