bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laminar mixed convection in the entrance region of shrouded arrays of heated rectangular blocks
Authors: Lin Jenn‐Nan , Yen Chen‐Shyong , Chou Fu‐Chu 
Published: March 2009

AbstractLaminar mixed convection in the entrance region of shrouded arrays of heated rectangular blocks is approximated numerically for large Prandtl number fluids. The problem considered is related to the convective cooling of electronic components mounted on horizontal circuit boards. Two heating conditions are investigated; in case 1, the uniformly heated components are facing upwards and, in case 2, the heated components are facing downwards. Typical fluid streamlines and isotherms, block wall temperature distributions and local Nusselt numbers are presented. It is found that the secondary flow leads to a significant enhancement in heat transfer for cases where the block faces upwards rather than downwards.
Analysis of deactivation disguised kinetics in transport reactors by periodic operation
Authors: Sivakumar S. , Chidambaram M. , Shankar H. S. 
Published: March 2009

AbstractDeactivation disguised kinetic schemes in an isothermal transport reactor are differentiated by means of periodic operation of the reactor. A periodic rectangular pulse is assumed for the inlet concentration. Three numerical examples are given to demonstrate that the deactivation disguised kinetic models give different conversions under periodic operation.
Mixing and segregation in a liquid fluidized bed of particles with different size and density
Authors: Dutta B. K. , Bhattacharya Suman , Chaudhury S.K , Barman B. 
Published: March 2009

AbstractExperimental studies have been carried out on fluidization of irregular particle mixtures of different size and density. The mixing and segregation phenomena could be interpreted on the basis of the diffusion model of Kennedy and Bretton. The dependence of computed particle dispersion coefficient on liquid velocity, particle density and size has been discussed.
Reduction kinetics of Fe(III)NTA chelate by sulfite
Authors: Sada E. , Kumazawa H. , Yoshikawa Y. , Rudziński K. J. 
Published: March 2009

AbstractKinetics of the reduction of Fe(III)NTA (ferric ion coordinated to nitrilotriacetic acid) by sulfite were studied experimentally in aqueous solutions at 40‐60°C and pH = 3.8‐8.3. The reaction had been claimed to be a regeneration step of Fe(II) in the absorption of nitric oxide into aqueous solutions containing Fe(II)NTA and sulfites. The reaction rate could be expressed as first‐order with respect to the concentration of Fe(III)NTA and of order minus one with respect to the concentration of Fe(II)NTA. The order of reaction with respect to HSO−3 was determined to be unity when the molar ratio of Na2SO3 to Fe(III)NTA was less than 5.
Dispersion dans les lits de particules avec écoulement pulse
Authors: Condoret J. S. , Riba J. P. , Angelino H. 
Published: March 2009

AbstractLe but de ce travail est l'étude de la modification hydrodynamique, comme par exemple l'état de mélange, engendrée par la superposition de mouvements périodiques à l'écoulement principal dans un réacteur fluide‐solide à lit fixe. Nous nous proposons ici de choisir une description adéquate de l'hydrodynamique du réacteur pulsé, de définir les paramètres impliqués et par une expérimentation spécifique, de déterminer leurs valeurs. Une corrélation pour le calcul du coefficient de dispersion axiale a pu ětre établie:
Studies on the inhomogeneous nature of the silent discharge reactor: Part 3. A multi‐zoned flow model
Authors: Khan A. A. 
Published: March 2009

AbstractThe reaction space of a silent discharge reactor consists of two distinct components, viz. (1) the collection of primary reaction zones (PRZ) or discharge streamers where, under the influence of free electron avalanches, primary electron molecule collisions take place and (2) the remaining reaction space which provides for secondary or quenching reactions between activated species and gas molecules. A flow model based on this concept has been proposed which accounts for the intrinsic chemical activity of the PRZs as well as their random distribution, spatial location, transient nature, and temperature field. Experimental results obtained on laboratory ozonizers have been examined to show the validity of the proposed model.
The behaviour of segregating fluidized beds and its relevance to ash management
Authors: Bemrose C. R. , Botterill J. S. M. , Bridgwater J. , Nienow A. W. , Weiping Yan 
Published: March 2009

AbstractVisual observation of the movement of particles across a transparent, drilled plate distributor allowed their directional and RMS velocities to be determined. Particles too big and/or dense to be lifted by bubble wakes are moved towards collection zones by the circulating bed material. The minimum fluidizing velocity has to be exceeded by an amount which increases with increasing density and/or number of particles before there is significant transport. Direct and RMS velocities increase linearly with the gas velocity. Circulation is controllable by producing imbalance in the air supplies to different zones of the distributor; tilting the distributor (flow is then up the slope); or use of a spout as a pump. Spouts can remix large/dense particles back into the bulk of the bed. Particles can be selectively withdrawn through a pneumatic off‐take tube.
Correlation of reactivity with chemical structure: Thermal hydrogenation of gas oils
Authors: Gray Murray R. , Khorasheh Farhad , Lana Ivo G. Dalla , Yeniova Hasip 
Published: March 2009

AbstractThe relationship between chemical structure and reactivity for thermal hydroprocessing was studied for five gas oils derived from Alberta bitumens. Chemical structure was characterized by combining data from 1 H and 13 C nuclear magnetic resonance spectroscopy, class fractionation, and elemental analysis to calculate structural parameters. Thermal hydrotreating was performed in a continuous‐flow stirred reactor at 420 and 440°C, 13.9 MPa hydrogen pressure, and 1.5 h1 LHSV. Conversion of the 343–525°C boiling fraction of the gas oils was correlated with the concentration of naphthenic methylene groups in the feed. Formation of methane and ethane was dependent on the degree of condensation of the aromatic rings in the feed oils. Thermal desulfurization was highly correlated with the amount of saturates in the feed, and the aromaticity of the resin fraction. Hydrogen consumption increased with the aromaticity of the gas oil…
The computer‐derivation of thermodynamic equations Part III. Chemical systems
Authors: Jubb D. J. A. , Missen R. W. 
Published: March 2009

AbstractAn algorithm, THERMODER4, based on Jacobians, is presented for automating the symbolic derivation of expressions for thermodynamic derivatives for chemical systems, to complement algorithms given previously for unrestricted simple and complex systems. The algorithm is implemented by a program using an augmented computer‐algebra system together with a microcomputer. Examples are given to illustrate the use of the algorithm in transforming variables and in sensitivity analysis for systems at equilibrium.
Empirical strategies for open‐loop on‐line optimization
Authors: Mcfarlane R. C. , Bacon D. W. 
Published: March 2009

AbstractTwo empirical strategies for open‐loop on‐line optimization are developed as alternatives to the use of mechanistic process models. These strategies are based on on‐line identification of dynamic multi‐input single‐output (MISO) and multi‐input multi‐output (MIMO) models. The steady state gain of these models provides information for steady state optimization. Desirability functions, originally developed for multi‐objective optimization, are utilized as objective function modifiers for constrained on‐line optimization. The integration of dynamic model identification and desirability functions results in an on‐line optimizer which combines fast optimizing speed with the ability to predict future encroachments on constraint boundaries. Corrections to the search direction are based on these predictions, reducing the probability of actual constraint violation.The optimization strategies are tested by simulation on nonlinear multivariable interacting systems at two levels of complexity: a CSTR supporting a multiple reaction and a fluid catalytic cracker. Both methods were effective in avoiding violation of constraints but the MIMO strategy required fewer steps to reach an optimum and was less prone to generate a nonfeasible optimization step.
Heat transfer in a continuous bubble column
Authors: Chen B. H. 
Published: March 2009

AbstractThe effective thermal conductivity ke was measured for a continuous bubble column operating within the bubbly flow regime. ke was found to be independent of liquid flow rate but strongly dependent on gas flow rate and physical properties of the liquid phase over the ranges 0.1>uG>4 cm/s, 0>uL>3.4 cm/s, 0.00096> μ >0.0028 kg/m μ s and 0.047 >σ>0.072 N/m.
The spouting regime map, bubbling characteristics and bed expansion of deep beds of large hollow polyethylene spheres
Authors: Zamora R. , Littman H. , Morgan M. H. 
Published: March 2009

AbstractThe high velocity spouting regime of a deep bed containing 9.6 mm hollow polyethylene spheres of density 394 kg/m3 was investigated in a 152.4 mm flat bottom cylindrical half column with a 50.8 mm inlet. A bed height vs gas velocity regime diagram is presented showing the conditions under which type II spouting is observed. The transition velocity from bubbling to type II spouting is determined using the autocorrelation of the pressure fluctuations in the bed. The bubbling characteristics of the bed are described. Bed expansion in bubbling and type II spouted beds are reported.
Pressure equalization in diffusion cells
Authors: Trigg David , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractDesign of a pressure equalization device is described that imposes a fixed pressure to minimize the relative importance of pressure fluctuations in steady state, counterdiffusion measurements employing a Wicke–Kallenbach diffusion cell. The success of this design is shown in observing gas diffusion in a liquid‐filled, porous, sintered–steel plate.
Experimental measurements of local axial gas velocity and void fraction in simulated pwr steam generator rod bundles
Authors: Moujaes S. F. , Dougall R. S. 
Published: March 2009

AbstractA dual spherical tipped optical fiber probe is used to obtain new data on local axial gas velocity and void fraction in a 4 × 3 rod bundle simulating a PWR steam generator. The average volumetric fluxes used were Jg = 1.52 ‐ 2.44 m/s and J, = 0.47 ‐ 0.68 m/s. Significant variations of Vg and α were found to exist downstream from the support plate. However the α range did not show any significant change between the flow holes and that downstream position, while Vg showed a more substantial variation. Values of Vg and α were very different between locations in the clearance gap around the tubes and that in the main flow holes. The gas flow rate was estimated to be only between 1–2.0% of that in the flow holes which could explain in part the existence of deposits in the clearance gap, due to decreased liquid velocity, leading eventually to tube denting in a PWR application.
Continuous crystallization of potash alum: MSMPR kinetics
Authors: Jones A. G. , Mydlarz J. 
Published: March 2009

AbstractThe crystallization kinetics of potash alum (aluminium potassium sulphate) from aqueous and aqueous acetone solutions respectively in a continuous mixed‐suspension, mixed‐product‐removal (MSMPR) crystallizer (capacity 4 L) are reported. Growth and nucleation rates are determined by direct model estimation via the population balance analysis of crystal size distribution measured using laser light scattering and sieve analysis.The overall growth rate during drowning‐out precipitation strongly decreases with increasing acetone concentration in the crystallizing solution. Nucleation rates evaluated at zero‐size, however, are virtually unaffected while the “effective” nucleation rates are strongly increased by the presence of acetone with a reduction in the supersaturation order. Magma density dependence is approximately first order during cooling crystallization while a somewhat lower dependence is detected during drowning‐out precipitation.
An analysis of the elution curve in preparative chromatography with moving feed ports
Authors: Kubota Katsuyuki , Hayashi Shinya 
Published: March 2009

AbstractThe present work deals with the mathematical analysis of the elution curve in preparative chromatography with moving feed ports. To predict the elution curve for this moving feed mode, simple differential equations for mass transfer were employed and solved by using algorithms based on the Plate Theory and iteration methods. As a result, the least chromatographic band spreading was found on the moving feed mode rather than the non‐moving feed mode only if mass transfer resistance between the phases does not participate in the adsorption process. On the other hand, when the mass transfer is not very rapid, the chromatographic performance of the moving feed mode was found to be compatible with that of the non‐moving feed mode.
A three‐parameter cubic equation of state for fluids and fluid mixtures
Authors: Tsai Fuan‐Nan , Jan Dong‐Syau 
Published: March 2009

AbstractA new cubic equation of state with three parameters is developed. The substance‐dependent critical compressibility factor, ζ, and the temperature‐dependent parameter, α, were correlated in terms of the acentric factor and reduced temperature. The P‐V‐T relationships, vapor pressures, volumes, and enthalpy departures of pure substances, and the compressibility factors, enthalpy departures, and vapor‐liquid equilibria of mixtures were calculated with the proposed equation. Comparison of the calculated results with experimental data shows that the proposed equation is accurate enough to be applied for design purposes.
Taking advantage of available cubic equations of state
Authors: Adachi Yoshinori , Lu Benjamin C.‐Y. , Sugie Hidezumi 
Published: March 2009

AbstractAll available simple cubic equations of state (EOS) are developed for specific representations. An effort has been made to take advantage of these existing equations for binary vapor‐liquid equilibrium (VLE) as well as density calculations by assigning different EOS to different components of the mixture under consideration. A four‐parameter cubic equation was used for combining the equations in the calculation. The effect of substance‐dependent Ωac on vapor‐liquid equilibrium calculations was further investigated, using two sets of mixing rules. A criterion for selection of equations for VLE calculation by means of the proposed approach was suggested. The improvement in the prediction of liquid volumes for binary mixtures based on the fitting of pure component liquid volumes was very satisfactory.
Solubility of propylene gas in octane and various polar solvents
Authors: Hayduk W. , Wong C.‐F. 
Published: March 2009

AbstractPropene gas solubilities at 101.3 kPa pressure are reported in n‐octane, chlorobenzene, acetone, acetic acid, ethyl acetate, n‐butanol, N‐N‐dimethyl formamide (DMF) and ethylene glycol for a range of temperatures. These data, along with data from the literature, were used to show the qualitative effects of unsaturation of the gas component on the solubility in various solvents ranging from non‐polar to highly polar and associated solvents. This involved a comparison, when data were available, of the solubilities of ethane, ethylene and acetylene, then of butane, isobutane, isobutylene, trans‐2‐butene and 1,3‐butadiene as well as of propane and propene (propylene). The differences in solubilities could be explained using solubilities expressed as a molecular interaction parameter (mip) and by identifying several different types of molecular interactions. For associating solvents these effects can be summarized as follows:mip of acetylene > mip of ethylene > mip of ethane, also mip of propylene > mip of propane and mip of butadiene > mip of isobutylene≥ mip of trans‐2‐butylene > mip of butane > mip of isobutane.
Synthesis of model‐based controllers for an autothermal reactor
Authors: Chylla Richard W. , Çlinar Ali 
Published: March 2009

AbstractModel‐based controllers for a bench scale autothermal tubular packed‐bed reactor have been formulated using the Internal Model Control (IMC) approach. The Structural Dominance Analysis technique has been used in developing the reduced‐order models. Controller performance at robust and sensitive steady states have been assessed through simulations and experiments. Both PI and model‐based controllers can regulate reactor operation at robust steady states, but only third order IMC controllers are able to regulate reactor operation at the sensitive steady state.
An improved light attenuation technique for measuring large interfacial areas
Authors: Kasireddy V. K. , Al Taweel A. M. 
Published: March 2009

AbstractA laser‐based light attenuation technique was successfully used to measure interfacial areas as high as 5832 m2/m3 and Sauter mean bubble diameter varying between 50 and 5600 μm. Good agreement between this approach and the photographic technique was obtained particularly at low gas holdups.
Production of uniform drops of viscous liquids using a coaxial airstream
Authors: Blysniuk John W. , Sefton Michael V. 
Published: March 2009

AbstractThe effect of coaxial airstream velocity on the size of polymer solution droplets (300–1000 μm in diameter) extruded from a tapered needle have been measured and shown to be consistent with a force balance that equates the drag force to surface tension. However, droplet diameter was also dependent on polymer solution viscosity at higher air velocities (> 22 m/s), indicating that viscous dissipation forces must also be considered in the force balance. These results are relevant to the design of devices used to microencapsulate live mammalian cells which are based on similar extrusion techniques.
Isobaric vapor—liquid equilibria for binary systems composed of methyl butanoate with ethanol and with propan‐1‐ol at 114.66 and 127.99 kpa
Authors: Ortega Juan , Susial Pedro 
Published: March 2009

AbstractVapor‐liquid equilibrium data for the binary systems methyl butanoate/ethanol and methyl butanoate/propan‐l‐ol at pressures of 114.66 and 127.99 kPa are presented. Both mixtures yield an azeotrope, the compositions (ester) of which decrease quasi‐linearly as the pressure increases. The experimental data for all the binary mixtures were fitted to a suitable equation and then used for comparison with predictions by ASOG and UNIFAC methods. These group contribution models give a good estimation of activity coefficients with an overall mean error less than 5% for all cases.
An industrial cell biologist's wish list
Authors: Seaver Sally S. 
Published: March 2009

AbstractThe current state of protein production by eukaryotic cells in culture is reviewed by a cell biologist with an eye towards areas that could benefit from more work by chemical engineers. The basic question of how the type of bioreactor influences cell productivity has not been answered. We are still learning how to optimize protein production in all types of bioreactors. Recent examples show that optimization can increase productivity over 10‐fold. Support work needs to be done to determine the limits of individual cell productivity. Basic cell metabolism work needs to be done in serum‐free medium to make it generally applicable. Only then can better bioreactors be designed with useful probes to monitor important substances.
Insect cell cultivation techniques for the production of high‐valued products
Authors: Goosen Mattheus F. A. 
Published: March 2009

AbstractThe large scale cultivation of insect cells will likely play an increasingly important role for the commercial production of bioproducts. While much research work has been done on the engineering aspects of insect cell suspension culture, many questions remain unanswered (i.e. the nature of bubble damage in sparged reactors, shear sensitivity and adaptation of cells; the use of serum‐free medium). In addition, insect cell immobilization may become a suitable technique for enhancing cell densities and product concentrations. This article presents a brief critical review of the development of insect cell suspension culture techniques for the production of insect pathogenic viruses and recombinant proteins.The problems of culturing microencapsulated insect cells, infected with a temperature sensitive baculovirus, also is discussed.
Linear displacement of a wetting fluid by an immiscible non‐wetting fluid in a porous medium: A predictive algorithm
Authors: Kiriakidis D. G. , Mitsoulis E. , Neale G. H. 
Published: March 2009

AbstractThe linear displacement of a wetting fluid by an immiscible non‐wetting fluid in a two‐dimensional porous medium composed of a network of sites multi‐connected by bonds has been simulated mathematically. The algorithm involves Monte Carlo decision making, random walks and principles of the percolation theory. The algorithm described in the present work successfully predicts the three distinct behaviours of immiscible displacement in porous media. This algorithm is tested against experiments available in the literature for two‐dimensional porous media. The agreement between the numerical results and the experiments is very good.
Adaptive control of hydrodynamic holdup in a karr extraction column
Authors: Camurdan M. C. , Taylor P. A. , Baird M. H. I. 
Published: March 2009

AbstractAn application of a Clarke‐Gawthrop self tuning regulator to control the dispersed phase holdup in a Karr reciprocating plate extraction column is presented. The frequency of reciprocation was used to control holdup because of its speed of response and low cost. The relationship between the frequency of reciprocation and the dispersed phase holdup is highly nonlinear, and, therefore an adaptive controller has to be used to control this process. Previous work (Kusuma, 1981) on holdup control has been extended to cover a wider range of operating conditions and to prevent covariance windup by including an empirical discounting factor. The experimental results focus on the operating region near to flooding since this is the most difficult to control and is often closest to the optimal operating point. The advantages and limitations of the empirical discounting factor are discussed.
Emulsification of a viscous monomer mix: Particle size and size distribution
Authors: Chaffey Charles E. , Tasalloti Suzanne , Paine Anthony J. 
Published: March 2009

AbstractA non‐Newtonian mixture of monomers, their copolymer and pigment was dispersed into water with emulsifier by a rotor‐stator homogenizer (Brinkmann Polytron). Volume median diameters d50 of the droplets, measured by Coulter Counter or optical microscopy, were typically 4–20 μm; d50 was about inversely proportional to monomer fraction (0.2 to 1.0), or to rotor speed (4000 to 11000 rpm). Increasing the emulsifier from 0.1 % to 3% roughly halved d50; volume fraction of organic phase had little effect. Turbulent dispersion theory (Calabrese et al., 1986a, b), adapted to non‐Newtonian drops, represented the data but with different numerical constants. A high geometric standard deviation, around 1.7 but increasing slightly as monomer fraction decreased, may be due to non‐uniform turbulence and to the complexity of breakup at high viscosity.