bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model reference identification of state space models for a double effect evaporator
Authors: Chintapalli Prasad , Seborg Dale E. , Fisher D. Grant 
Published: March 2009

AbstractA model reference identification technique is used to develop state space models of a double effect evaporator from experimental and simulated data. The model reference technique is based on a Liapunov design approach and is successfully used to estimate coefficient matrices containing 18 parameters in a third order model and 40 parameters in a fifth order model. However, in this application the success of the model reference technique required low measurement noise levels and a judicious choice of design parameters.
Interfacial turbulence accompanying chemical absorption
Authors: Sada E. , Kumazawa H. , Butt M. A. , Lozano J. E. 
Published: March 2009

AbstractAbsorption rates for carbon dioxide into aqueous solutions of EDA and MEA with and without adding surface active agent were measured in a laminar liquid‐jet apparatus to check and verify the Marangoni effect. In addition, experiments were conducted for the tracer desorption of ethylene from aqueous EDA and MEA solutions into carbon dioxide or nitrogen stream. It has been concluded that the Marangoni effect cannot be neglected for such short contact times as in a laminar liquid‐jet. The Marangoni instability accompanying the present chemical absorptions is attributed to combinated effects of the presence of ionic products, the depletion of the reactant liquid near the interface and an increase in interfacial temperature.
Kinetic parameters of isotopic exchange reaction in finite bath
Authors: Huang Ting‐Chia , Tsai Fuan‐Nan 
Published: March 2009

AbstractA mathematical model has been proposed for an isotopic exchange reaction between the solid particles and ions in a solution of finite volume. A theoretical equation has been derived to predict the exchange fraction as a function of the dimensionless time T with the kinetic parameters ξ, ξ1 and final fractional uptake U as parameters for the exchange rate controlled by combined film diffusion, surface chemical reaction and intraparticle diffusion. The exchange fraction increases as the values of T, U, ξ and ξ, increase. Experimental results of the isotopic exchange systems CaCO3(s)Ca2+ (aq), CaC2O4(s)/ Ca2+ (aq) and Ca‐form Dowex 50W‐X8/Ca2+ (aq) agree well with the theoretical equation proposed in this study.
Kinetics of hydrogen reduction of nickel sulfide
Authors: Chida T. , Ford J. D. 
Published: March 2009

AbstractThe hydrogen reduction of powdered nickel sulfide (Ni3S2) at atmospheric pressure in the temperature range 475 to 630 °C has been experimentally investigated. The true intrinsic kinetics of this reaction were obtained, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 475 to 530 °C, the rate constant could be expressed by the following equation:

Above 530°C, whisker formation of nickel metal was observed. It was also shown that the thermal history of the powder had an important bearing on the results obtained − in general, preheating led to lower reduction rates.
The effects of mixing, temperature, and nutrient concentration on the fermentation of a mixed sugar solution simulating the hexose content of waste sulfite liquor
Authors: Pineault G. , Pruden B. B. , Loutfi H. 
Published: March 2009

AbstractThe results of changes in temperature, mixing and nutrient concentration on the conversion by yeast of D‐mannose, D‐galactose, and D‐glucose using Saccharomyces cerevisiae strain were studied. These sugars are present in waste sulfite liquor. From the operating conditions used in this study, the most rapid removal of sugars found at a pH of 5 were temperature 36°C, mixing 700 rpm, and nutrient concentration 13.3 g/1. The fermentation was carried in a three‐litre batch reactor and the main variables measured were dissolved oxygen, yeast growth, alcohol production, total sugar consumption, and D‐mannose, D‐galactose and D‐glucose utilization. It was found that the fermentation could be fitted to the published Kono‐Assai model.
Étude de la déshydratation des ethers de glycol comme une nouvelle voie de synthèse des vinyl‐ethers
Authors: Salazar‐Tello J. C. , Lena L. , Phan‐Tan‐Luu R. , Metzger J. 
Published: March 2009

AbstractA study has been made to determine the basic conditions to develop an economical manufacturing process for vinyl glycol ethers. To achieve the aforesaid purpose, the synthesis of the above‐mentioned products by means of glycol ether dehydration has been experimentally investigated; the most suitable way to achieve it has been found to be an indirect dehydration (pyrolysis of the corresponding acetates).After having found the best way of synthetizing the vinyl glycol ethers, a determination has been made of the parameters which have a significant influence on the reaction carried out, in the gaseous phase, in a glass tubular reactor under normal pressure.An optimization study has enabled to develop a model from which the maximum response area has been found, selectivity being the objective function.
Application of van't hoff's osmotic pressure equation to aqueous mixed electrolyte solutions
Authors: Tran Tuong‐Tu , Sangster James 
Published: March 2009

AbstractAn analogue of the compressibility factor for real gases has been applied to van't Hoff's osmotic pressure equation for aqueous solutions of single electrolytes. In addition, an analogue of Dalton's law for gas mixtures has been applied to mixed electrolyte solutions, which makes possible an estimation of the water activity (aw) of ternary solutions. The error in (aw) is approximately 0.1% for common‐ion systems (NaCl/KCl and NaNO3/Ca(NO3)2) and 0.5% for a system without common ions (KCl/NaNO3) at 25 °C.
Deposition of paraffin wax from kerosene in cooled heat exchanger tubes
Authors: Bott T. R. , Gudmundsson J. S. 
Published: March 2009

AbstractStudies of the deposition of wax from wax/kerosene mixtures onto cooled simulated heat transfer tubes has demonstrated that, following an initial deposition taking a relatively short period of time, the heat transfer resistance fluctuates with time.Theoretical estimates of temperature distribution in the experimental flowing wax/kerosene system suggest that the cloud point temperature of the mixture falls within the laminar boundary layer. Since the cloud point is considered the temperature at which particles of wax appear, the conditions within the boundary layer will influence deposition. Increased flowrate and temperature decrease the number of particles able to deposit while the number is increased by greater wax concentration in the bulk solution.
Hydrodynamic particle volume and fluidized bed expansion
Authors: Fouda A. E. , Capes C. E. 
Published: March 2009

AbstractParticulate fluidized bed expansion may be described by the Richardson‐Zaki equation,\documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = e^n $\end[document] The values of n for very fine and/or aggregated particles and for particles of irregular shape are often found to be larger than those for comparable spherical particles. Previous work on aggregated systems by one of the authors showed that a modified Richardson‐Zaki equation, \documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = \left( [1 - KC] \right)^n $\end[document] (where C = 1‐ε), provided a more consistent correlation of the data. The parameter K accounted for the effective hydrodynamic volume of the particles during fluidization and the application of this concept to non‐spherical particles was the subject of the present study. While K for spherical particles was essentially equal to unity, values from 1.17 to 1.43 were found for equidimensional but irregular particles with considerably higher values for flat particles. An equation relating K to particle shape is offered which, when combined with the Richardson‐Zaki relationships, provides a more accurate prediction of the expansion behaviour of non‐spherical particles.
A model for particle collection with potential flow between two parallel cylinders
Authors: Choudhary K. R. , Gentry J. W. 
Published: March 2009

AbstractA Model for predicting the collection efficiency of two parallel cylinders was developed for the case when the velocity field between the cylinders can be approximated by potential flow. The model uses the method of images.The efficiencies predicted from this model were compared with calculations for potential and viscous flow about a single cylinder as well as with the Harrop and Stenhouse model. The theory was compared with experiments by Fan.
Fluid‐particle hydrodynamics in agitated vessels
Authors: Ambegaonkar Anil S. , Dhruv Ashok S. , Tavlarides Lawrence L. 
Published: March 2009

AbstractA two dimensional model is proposed to predict mean radial and axial velocities for turbulently agitated fluids in baffled tanks with a turbine impeller.A particle dynamics model that simulates the movement of dipsersed phase particles in turbulent dispersion by a statistical Monte Carlo technique is coupled with this fluid dynamics model. The comparison of the flow directions, radial and axial velocity profiles, and the volumetric discharge capacities of the turbine impeller with the experimental data is favorable.
A simple three‐parameter equation of state with critical compressibility‐factor correlation
Authors: Horvath Csaba , Lin Hung‐Jye 
Published: March 2009

AbstractA three‐parameter equation of state is proposed for fluids whose critical compressibility factor is not greater than 0.275. The equation is third order in volume and its constants are evaluated from the critical temperature and pressure as well as from the premultipliers that are interrelated and dependent on the reduced limiting volume of the fluid. The premultipliers have been evaluated from a single compressibility‐factor correlation extrinsically. The proposed equation is as easy to handle mathematically as the Redlich‐Kwong equation and yields analytical expressions for various fluid properties. The results show, however, that it represents the properties of normal and polar fluids much more accurately, particularly in the saturated vapor and the liquid region.
Startup of a pipeline containing settled solid particles
Authors: Peters J. , Salazar A. , Shook C. A. 
Published: March 2009

AbstractExperimental studies have shown that, provided a threshold velocity is exceeded, bed of solid particles can be displaced from pipelines at low pressure gradients using fluid velocities near the limit‐deposit velocity. The time scale of the process depends upon three factors: fluid acceleration, bed erosion and displacement. Results are reported for water slurries of a silica send of d50 = 0.43 mm. A simple model for the transient response is proposed.
The effect of some alkaline additives on the viscosity of coal water slurries
Authors: Shook C. A. , Nurkowski J. 
Published: March 2009

AbstractThe viscosity‐reducing effects of various alkaline additives to coal slurries were studied. It was found that especially in combination with leonardite, a naturally oxidized form of lignite, significant reductions could be achieved for a bituminous and a sub‐bituminous coal. No reduction could be produced for lignite slurries, however.
Inclined hot‐wire response equations for a flow field having a dominant tangential velocity component
Authors: Bank Nader , Gauvin W. H. 
Published: March 2009

AbstractModified sets of response equations have been derived for a single inclined hot‐wire probe introduced in various orientations in a flow field having a dominant tangential velocity component. By means of these equations, the components of the three dimensional mean velocity vectors, the turbulence intensity and the Reynolds stresses can be easily determined at any location in a swirling flow which is stationary with time. This method is particularly applicable to the characterization of the flow field in chemical processing equipment where this type of swirling flow is increasingly being used. It has been successfully applied to a study of the flow field in a spray‐drying chamber, in the course of which good reproducibility and consistency of results were obtained.
Enhancement of liquid extraction by an instantaneous, irreversible reaction
Authors: Miller Joseph W. , Harper Dean O. 
Published: March 2009

AbstractA quasi‐steady state analysis was applied to the enhancement of liquid extraction by a chemical reaction. Ethylene glycol drops were allowed to fall through a stationary heptane phase containing iodine (component A) in a 2.42 cm I.D. column operated at varying heights. The overall mass transfer coefficient, after elimination of end effects, for iodine from heptane into the glycol drops was determined to be K° = 0.213 mol/(s.m.2).By the addition of sodium thiosulfate (component B, Na2S2O3) to the inlet glycol, an instantaneous and irreversible reaction
I2 + 2Na2S2O3 → Na2S4O6 + 2NaI
took place in the glycol phase, increasing the value of K to a maximum value of 0.5 mol/(s.m2).
Compensation effect and its use in catalyst correlations
Authors: Ranganathan R. , Bakhshi N. N. , Mathews J. F. 
Published: March 2009

AbstractCatalysts of varying surface properties (e.g. surface area, pore volume and crystallite size) and of varying bulk properties (e.g. metallic radius, heat of formation of oxide and percentage d‐character) were evaluated as catalysts for the decomposition of hydrogen peroxide. Surface properties were varied by studying the following catalysts: unsupported nickel oxide, nickel oxide/α‐alumina, nickel oxide/α‐alumina and nickel oxide/silica‐alumina. The bulk properties were varied by studying the oxide catalysts of different metals such as nickel, chromium, mangenese, cobalt and palladium. The results obtained from this work along with the data obtained from a search of the literature, were correlated using a compensation plot (linear relationship between the activation energy and the logarithm of the frequency factor). General correlations for bulk properties and catalytic activities are presented for the decomposition of hydrogen peroxide. The use of a “Compensation Effect” for the hydrogenation of ethylene is also discussed.
The effect of flow regime on the continuous emulsion polymerization of styrene in a tubular reactor
Authors: Rollin A. L. , Patterson I. , Bataille P. , Huneault R. 
Published: March 2009

AbstractFive isothermal emulsion polymerizations of styrene in a tubular reactor were studied experimentally using an emulsifier concentration in the vicinity of the critical micelle concentration (CMC). The flow regime was characterized by an emulsion Reynolds Number (NRe)e calculated using the emulsion properties prior to any appreciable reaction.It was found that the rate of polymerization was a maximum at the laminar‐turbulent transition based on (NRe)e. This behavior is similar to emulsion polymerizations carried out in batch reactors where a maximum rate of polymerization has been observed when the agitation level (agitator rotation rate) is varied. The controlling mechanisms appear to be similar at high agitation levels but differ when the emulsion is weakly agitated.
Processing athabasca tar sands — tailings disposal
Authors: Camp Frederick W. 
Published: March 2009

AbstractPublic awareness and concern over the tailings disposal aspects of tar sand development are increasing. This paper describes why the hot water extraction process can lead to an accumulation of tailings sludge. A theory is proposed to predict tailings accumulation rate; predictions are compared with GCOS' operating experience. Using this theory, future projects can be evaluated on their merits without extrapolating GCOS' experience, which may or may not be applicable. Several unsuccessful approaches to reducing sludge accumulation are described to encourage others to seek new approaches.
A study of phosphate hide‐out from boiling water
Authors: Balakrishnan P. V. 
Published: March 2009

AbstractSodium phosphates deposit on heat transfer surfaces from boiling solutions. This process of deposition, which is termed “hide‐out”, was studied in a recirculating loop operating at the temperature and pressure of the secondary system in CANDU‐PHW* steam generators. The relation between the compositions of the deposit and solution, is in agreement with studies by others. An additional depletion of phosphate was found, which probably related to reaction with corrosion product deposits on the loop surfaces. The observations from this study suggested a maximum desirable range for Na/PO4 molar ratio in solution of 2.2 to 2.6 for phosphate treatment of steam generator water.Lithium phosphate treatment is unsuitable because it forms hard scales and also causes accelerated corrosion of boiler tubing.
The analysis and design of binary vapour‐liquid equilibrium experiments. Part II: The design of experiments
Authors: Sutton Thomas L. , Macgregor John F. 
Published: March 2009

AbstractStatistical theory on the optimal design of experiments is used to demonstrate how one might design binary vapour‐liquid equilibrium experiments to yield the greatest amount of information on the unknown parameters in semi‐empirical thermodynamic models. The design of an isothermal or isobaric equilibrium experiment is considered to involve the choice of the liquid phase composition at which the experiment should be performed. Examples are used to illustrate how these procedures can be used to select experimental regions which would yield the most information on the parameters and to reveal other regions in which very little information would be obtained.
Guidelines for the optimal design of experiments to estimate parameters in first order kinetic models
Authors: Reilly Park M. , Bajramovic R. , Blau G. E. , Branson D. R. , Sauerhoff M. W. 
Published: March 2009

AbstractThe optimal designs for experiments to estimate velocity and equilibrium constants in first order chemical kinetic situations are examined. Equations and charts which choose optimal designs are presented. A bioconcentration test using fish as the test organism is used to illustrate the problem and some good experiments of this type performed in the past are compared for efficiency with the corresponding optimal ones. Examples are also given of the statistical analysis of this type of experiment.
Effect of orifice shape on air atomized water spray characteristics
Authors: Beeckmans J. M. , Chan E. W. 
Published: March 2009

AbstractA study has been made of the dispersion characteristics of air atomized water sprays from injection orifices oriented normally to the air flow in a duct. Circular sectioned and rectangular sectioned orifices were employed, for both parallel and perpendicular orientation of the longest dimension of the rectangular orifices, with respect to the air flow direction. Rectangular orifices were found to produce more widely dispersed sprays than circular arifices of approximately equal cross‐sectional area, under otherwise identical conditions. The reasons for these observations are not understood; further studies on droplet size distributions and other factors are indicated.
Rheological comparison of three polyethylene film resins
Authors: Dealy John M. , Garcia‐Rejón Andrés , Kamal Musa R. 
Published: March 2009

AbstractSeveral rheological tests have been carried out on low density, film‐grade polyethylenes manufactured by three Canadian companies. The resins all have densities around 0.92, but are made by different processes. The Union Carbide resin is made in a tubular reactor, the C.I.L. resin in a two‐stage autoclave and the DuPont of Canada resin by means of a low pressure copolymerization process.The shear viscosity was determined for each resin over a wide range of shear rates at several temperatures, and the first normal stress difference was determined at low shear rates. Die swell was measured at the higher shear rates. The low‐pressure copolymer was found to be quite similar in its behavior to the resin made in a high pressure autoclave.Correlations between the various properties measured, proposed by Abdel‐Khalik et al(7) on the basis of the Goddard‐Miller constitutive equation(8), were tested and found not to be obeyed. A method proposed by Tanner for calculating die swell from the viscometric functions is also evaluated.
A three‐parameter markov model for sedimentation
Authors: Tory E. M. , Pickard D. K. 
Published: March 2009

AbstractConsidering velocity perturbations as white noise and assuming exponential decay of velocities to the mean velocity μ, we obtain a two‐parameter Langevin equation. The conditional and steady‐state probability density functions for instantaneous velocity are used to develop theoretical expressions for variables which can be measured experimentally. Support for the model is adduced from published data and our own experimental results. The parameter μ is obtained from the mean of the distance travelled in time T during steady state and the two Langevin parameters from its correlation coefficient and variance. Precision and bias in experimentation are discussed.
Freezing of liquids in turbulent flow inside tubes
Authors: Shibani Ali A. , Özisik M. N. 
Published: March 2009

AbstractThe problem of steady‐state freezing of liquids in turbulent flow inside a tube with its walls kept at a uniform temperature lower than the freezing temperature of the liquid is solved for a wide range of Reynolds and Prandtl numbers, 104 ≤ Re ≤ 104 and 0 ≤ Pr ≤ 103. The effects of Prandtl and Reynolds number on the location of the solid‐liquid interface and on the heat transfer rate as a function of position along the tube are established.
On the representation of liquid properties of pure polar compounds by means of a modified redlich‐kwong equation of state
Authors: Chung W. K. , Lu Benjamin C.‐Y. 
Published: March 2009

AbstractThe temperature‐dependent parameters ωa and ωb of the Redlich‐Kwong equation of state were evaluated from saturated liquid volumes and vapor pressures for three polar compounds, water, ammonia and sulfur dioxide, and then correlated in terms of Tr. To demonstrate the applicability of the resulting correlation, the values of ωa and ωb computed from these equations were used to evaluate the liquid properties of these compounds, such as vapor pressures and liquid volumes at saturation, and the heat of vaporization at the normal boiling point. In addition, the enthalpy departures of liquid water as well as the liquid volumes of compressed water were calculated. The results obtained from the proposed correlations are generally superior than those obtained from the equations of state recently proposed by Fuller, and Peng and Robinson.
The measurement and prediction of the solubility of acid gases in monoethanolamine solutions at low partial pressures
Authors: Nasir Pervaiz , Mather Alan E. 
Published: March 2009

AbstractAn apparatus for the determination of the solubility of hydrogen sulphide, carbon dioxide and their mixtures in ethanolamine solutions at low pressures is described. With this apparatus, the solubility of H2S, CO2 and their mixtures in aqueous solutions of monoethanolamine has been measured at partial pressures between 0.001 kPa and 9 kPa at temperatures of 80° and 100°C. The results for the mixture have been compared with two methods of prediction based on a thermodynamic model.