bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic hydrogenation of carbon monoxide to alkenes over partially degraded iron‐cobalt complexes
Authors: Snel R. 
Published: March 2009

AbstractComplex‐derived iron–cobalt alloy catalysts have been studied under conditions similar to those normally prevailing in industry. Despite reports in the literature indicating unusual selectivities with iron–cobalt alloy catalysts under atmospheric pressure conditions, no deviations from normal selectivity behaviour have been observed when studied under steady‐state conditions and pressures of 2.0 MPa. However, when promoted with manganous oxide or supported on silica‐alumina, substantial deviations from Anderson‐Schulz‐Flory statistics occur during the first few days on stream. These deviations gradually disappear with increasing time on stream leading to normal selectivity behaviour.The unsupported catalysts displayed remarkably high activity and selectivity maintenance, in contrast to supported catalysts, which show substantial oscillations in the catalytic behaviour.
An analysis of laminar forced convection film boiling
Authors: Rajagopalan Vijay , Subramanian V. 
Published: March 2009

AbstractA study of forced convection film boiling on a horizontal isothermal plate is made using a treatment based on boundary layer theory. For the vapour, the velocity and temperature distributions are obtained from equations of motion and energy. For the liquid layer, the Howarth approximation for flow over a plate is used. Then, by employing interface matching conditions, the significance of the rhμ ratio between the vapour and the liquid on the variation of Nusselt number is examined.
Three‐dimensional turbulent flow in agitated vessels with a nonisotropic viscosity turbulence model
Authors: Ju S. Y. , Mulvahill T. M. , Pike R. W. 
Published: March 2009

AbstractSolutions of the time‐averaged equations of motion with a nonisotropic k‐e model were developed for the three‐dimensional turbulent flow field in turbine stirred tanks. These results were validated with the measurements of three velocity components with a hot wire anemometer and literature data. The nonisotropic turbulence model considered the rotation and curvature effect of the turbulence with a turbulent Richardson number term and accounted for the important three‐dimensional effects through the nonisotropy of the viscosity. Also, it was found that a frequently used isotropic k‐ϵ turbulence model did not describe this three‐dimensional turbulent flow field.
Mathematical modeling of the elutriation of fine materials from rotary kilns
Authors: Tackie E. N. , Watkinson A. P. , Brimacombe J. K. 
Published: March 2009

AbstractA simple mathematical model has been developed to predict the influence of operating and material variables on the elutriation of fine materials in rotary kilns. The model is based on the mechanism of particle saltation which was observed to be the predominant mode of transport of entrained materials in a previously reported experimental study. For the model knowledge is required of the particle saltation height and the threshold shear stress for particle movement. The model predictions agree well with experimental measurements made in a laboratory rotating cylinder and with the scanty data in the literature. Application of the model to single‐pass industrial kilns such as cement, limestone and alumina kilns is presented.
A new experimental method to specify the diffusing component in a reacting particulate packing
Authors: Hao Yu‐Jun , Tanaka Tatsuo 
Published: March 2009

AbstractAnalysis of the solid‐solid reaction rate has been made, based on the reaction mechanism controlled by the unidirectional diffusion, or by the counter diffusion of the components. To judge which is the diffusing component, the “marker” method has been used so far. However, due to the problems involved the results obtained are sometimes different by different workers even for the same system. The authors propose in this paper a new method to judge the diffusing component in accordance with the difference in the dependence of reaction rate upon the particle size ratio, which was developed in the course of our study on the model of solid‐solid reactions. Examples are demonstrated by using the existing experimental data.
Effect of a row of cylindrical obstructions on mass transfer in creeping flow in a plate‐type membrane separator
Authors: Ishimi Kosaku , Koroyasu Sadatoshi , Ishikawa Haruo , Hikita Haruo 
Published: March 2009

AbstractCreeping flow across a row of cylinders located between a membrane and a solid plate and mass transfer from the fluid stream through the membrane were studied theoretically. A numerical solution for the product of the friction factor and the Reynolds number was obtained and found to be a function of the dimensionless diameter γ. A numerical solution for the Sherwood number, Sh, was expressed as a function of the Peclet number, Pe, the dimensionless diameter, γ, the number of cylinders, n, and the dimensionless membrane permeability, P. The solution for mass transfer indicated that, with increasing γ, Sh increases at large values of Pe and small values of n, while Sh decreases at small values of Pe and large values of n.
On the representation of pure‐compound saturated (ZV − ZL) values
Authors: Sugie H. , Iwahori Y. , Lu B. C.‐Y. 
Published: March 2009

AbstractAn equation for determining the difference between the compressibility factors of saturated vapor and liquid (ZV ‐ ZL) through cubic equations of state has been developed as a function of reduced vapor pressure Pr, reduced temperature Tr and the critical cohesion parameter Ωac of the chosen equation. The regressed equation has been presented in a polynomial expression of (Pr/Tr) and Ωac for simple non‐iterative calculations.
A model for trickle bed reactors in view of changing gas velocity
Authors: Lekshmi‐Narayanan H. , Pan Chin‐Min , Haure Patricia M. , Hudgins R. R. 
Published: March 2009

AbstractThe trickle‐bed reactor model of Goto and Smith (1978) is modified to account for changes in the gas velocity as a result of the solubility of the active gaseous species in the liquid phase, its rate of uptake by the liquid, and the extent of its participation in the reaction. There appear to be practical cases for which changes in the velocity of the gas phase should not be ignored.
Liquid fuels from canadian peat by the waterloo fast pyrolysis process
Authors: Piskorz J. , Majerski P. , Scott D. S. 
Published: March 2009

AbstractTwo Canadian peats from Quebec were pyrolyzed using the Waterloo Fast Pyrolysis Process (WFPP) technology with the objective of maximizing liquid yields. A young sphagnum peat (Sogovex) gave maximum yields of organic‐liquids (moisture free basis) of 45% to 47% in an optimum range of 450° to 550°C at atmospheric pressure. Char yields decreased from 35% to 26% and gas yields increased from 12% to 17% over this range. The character of the liquid product changed significantly over the optimum temperature range, with the ratio of water‐soluble to water‐insoluble components decreasing from 2.3 to 0.6, with an accompanying decrease in oxygen content.Pyrolysis tests using an old black peat (Premier) gave similar results, although with some what lower yields of organic liquids and higher char yields.Upgrading tests on the peat oil done under hydrodeoxygenation conditions in collaboration with Battelle PNWL resulted in a yield of about 33% of the liquid feed as a gasoline‐like liquid.
Managing the water chemistry of a CANDU reactor with an expert system
Authors: Lamirande S. , Roberge P. R. 
Published: March 2009

AbstractThe aim of this project was to capture the expertise of Ontario Hydro in the water chemistry of the heat transport system (HTS) of the CANDU nuclear reactor and transform it into an Expert System prototype. The end product is an Expert System which can realistically diagnose situations and recommend proper courses of action based on the user's water chemistry analysis.
Reactor design from batch data by a direct graphical method
Authors: Lobo Luís S. 
Published: March 2009

AbstractA graphical method for reactor design is presented which uses the plot of concentration vs. time. This method can be used to compare stirred tank, plug flow and recycle reactors as well as various reactor combinations. With Monod Kinetics the concept of wash‐out can be illustrated. A brief comparison with other graphical methods is made.
Fundamental investigation of plug conveying of cohesionless particles in a vertical pipe (pressure drop and friction of a stationary plug)
Authors: Tsuji Y. , Asano R. 
Published: March 2009

AbstractA stationary packed bed of cohesionless particles is set up in a vertical pipe for the fundamental study of plug conveying. The effect of flow acceleration or deceleration on the pressure drop of the plug is investigated first. It is found that the pressure drop increases due to the flow acceleration and vice versa. Next, the following three kinds of experiments were made for the study of friction characteristics: 1. Friction between the plug and moving wall without air flow, 2. Friction between the plug and wall with downward air flow, 3. Friction between the plug and wall with upward air flow. The results are compared with the theory established in powder mechanics. The state of stress being of the active or passive case is discussed. Finally the problem of particles raining down from the back of the plug is studied. It is shown that the air velocity necessary to support the particles can be calculated based on a simple analysis of pressure distribution around the particles.
Combustion characteristics of a two‐stage swirl‐flow fluidized bed combustor
Authors: Lee J. K. , Hu C. G. , Shin Y. S. , Chun H. S. 
Published: March 2009

AbstractIn order to investigate the combustion characteristics of a two‐stage swirl‐flow fluidized bed combustor, combustion experiments of low‐grade anthracite coal were performed. Experimental parameters were the fluidizing air velocity, coal feed rates, bed temperature, stoichiometric air ratio, swirl nozzle diameter and rotational diameter. The experimental results showed that, due to the swirl flow, the elutriation rates of fines were lower than those of the single‐stage fluidized bed combustor. The combustible contents of the ash in the outflow streams were also reduced. Therefore, the combustion efficiency of the two‐stage swirl‐flow fluidized bed combustor was 20% greater than that of the single‐stage fluidized bed combustor under the same operating conditions.
Epoxidation of oleic acid with oxygen in the presence of benzaldehyde using heterogenized homogeneous co‐type ion‐exchange membrane as catalyst
Authors: Kuo Ming‐Chao , Chou Tse‐Chuan 
Published: March 2009

AbstractThe epoxidation of oleic acid with oxygen in the presence of benzaldehyde to produce epoxidized oleic acid using a Co‐type ion‐exchange membrane as catalyst was carried out. No leakage of cobalt ion was found during the experimental runs. The epoxidized oleic acid was formed by a series of free radical reactions. Experimental results show that at 70% conversion of oleic acid, 60% of the total theoretical epoxidized oleic acid was obtained, illustrating the high selectivity (86%). The rate‐determining steps were experimentally identified and the formation rate of epoxidized oleic acid was found.
Electrosynthesis of sodium dithionite in a trickle‐bed reactor
Authors: Oloman Colin , Lee Ben , Leyten Wayne 
Published: March 2009

AbstractSodium dithionite was generated by electroreduction of sulphur dioxide on a graphite fibre mat cathode in a continuous ‘flow‐by’ trickle‐bed electrochemical reactor. Reactor performance was measured with respect to variation of the feed catholyte NaOH concentration [0.5‐1.0 mol/L], feed gas SO2 concentration [4‐40 vol%], product catholyte pH [2.4‐12.0] and applied current [10‐50 A (0.4‐2.0 kA/m2)]. Product catholyte temperature was in the range 18 to 30°C. With product catholyte pH between 2.4 and 6.9, dithionite was generated at current efficiency from 42 to 100%, concentration from 0.05 to 0.78 mol/L, yield from SO2 up to 69% and specific energy from about 2 to 5 kWh/kg Na2S2O4. Current efficiency fell with increasing current and rose with increasing gas load. High levels of thiosulphate [0.07‐0.3 mol/L] and sulphide [0.01‐0.13 mol/L] measured in the product catholyte would compromise the use of this process in commercial applications such as brightening wood pulp.
Estimation of parameters in monte carlo modelling
Authors: Duever T. A. , Reilly P. M. 
Published: March 2009

AbstractThis paper presents a general method for estimating model parameters from experimental data when the model relating the parameters and input variables to the output responses is a Monte Carlo simulation. From a statistical point of view a Bayesian approach is used in which the distribution of the parameters is handled in discretized form as elements of an array in computer storage. The stochastic nature of the Monte Carlo model allows only an estimate of the distribution to be calculated from which the true distribution must then be estimated. For this purpose an exponentiated polynomial function has been found to be useful. The method provides point estimates as well as joint probability regions. Marginal distributions and distributions of functions of the parameters can also be handled. The motivation for exploring this alternative parameter estimation technique comes from the recognition that for some systems, particularly when the underlying process is stochastic in nature, Monte Carlo simulation often is the most suitable way of modelling. As such, the Monte Carlo approach increases the range of problems which can be handled by mathematical modelling.The technique is applied to the modelling of binary copolymerization. Two models, the Mayo‐Lewis and the Penultimate Group Effects models, are considered and a method for discriminating between these models in the light of sequence distribution data is proposed.
A new approach using canonical correlation combined with advanced analytical techniques to simulate a chemical process
Authors: Chakravarty T. , Khan M. Rashid , Meuzelaar H. L. C. 
Published: March 2009

AbstractAn important requirement for mathematical modeling of chemical reactors is a means for simulation of the underlying chemical process. The goal of any reactor simulation is to enable prediction of the yield and composition of the products. This study shows the potential application of canonical correlation in combination with advanced analytical techniques (such as GC‐MS, FTIR, Py‐MS) toward modeling and prediction in chemical reactors. The mathematical description presented allows generalization of this approach.
The error‐in‐variables model applied to parameter estimation when the error covariance matrix is unknown
Authors: Keeler Scott E. , Reilly Park M. 
Published: March 2009

AbstractThis paper presents a method for Error‐in‐Variables Model (EVM) analysis when there is no prior knowledge of the error structure, but there is replication in the data. The method is presented, with examples, for cases where the error structure varies among the data, and for cases where the error structure is constant over all the data. The minimum amount of replication needed is discussed and posterior probability density functions are developed for the parameters. The results are an extension of the work of previous authors.
Statistical process control procedures for correlated observations
Authors: Harris Thomas J. , Ross William H. 
Published: March 2009

AbstractMeasurements from industrial processes are often serially correlated. The impact of this correlation on the performance of the cumulative sum and exponentially weighted moving average charting techniques is investigated in this paper. It is shown that serious errors concerning the “state of statistical process control” may result if the correlation structure of the observations is not taken into account. The use of time series methods for coping with serially correlated observations is outlined. Paper basis weight measurements are used to illustrate the time series methodology.
Friction factor for gas‐non‐newtonian liquid flow in horizontal bends
Authors: Das S. K. , Biswas M. N. , Mitra A. K. 
Published: March 2009

AbstractExperimental investigations have been carried out to evaluate the two‐phase pressure drop data across different types of horizontal bends for gas‐non‐Newtonian liquid flow. The non‐Newtonian liquids used were different concentrations of the sodium salt of carboxymethyl cellulose (SCMC) which behaved like pseudoplastic fluids. Correlations have been developed to predict the gas‐non‐Newtonian liquid two‐phase friction factor as a function of various physical and dynamic parameters of the system. Statistical analysis of the correlations suggests that the correlations are of acceptable accuracy.
A study of the deposition of silt onto the surface of type 304 stainless steel
Authors: Turner C. W. , Lister D. H. 
Published: March 2009

AbstractThe deposition rate of Lake Ontario silt onto type 304 stainless steel at a fluid velocity of 1.05 m/s is given by:N = 2.1 × 10−5 exp (‐E/RT) Cb p.where E = 25.3 kJ/mol. Both the magnitude and the temperature dependence of the deposition rate is consistent with deposition that is surface rather than transport limited. The release rates were small compared to the deposition rates and independent of the surface temperature. Only particles less than 5 μm were found in the deposits at 1.05 m/s, even though particles up to 25 μm were in the flowing silt suspension. The maximum particle size in the deposit decreased with increasing deposition velocity.
Motion of pulp fibre suspensions in rotary devices
Authors: Bennington C. P. J. , Kerekes R. J. , Grace J. R. 
Published: March 2009

AbstractSuspensions of semi‐bleached kraft pulp at low and medium mass concentrations were sheared in a rotary shear tester at angular velocities up to 524 rad/s (5000 rpm). The use of baffled housings, with rotors having lugs, imposed shear within the body of the suspensions and prevented slip at the vessel walls. The torque was measured as a function of angular velocity, and high speed photographs were taken through a transparent plate to aid in interpretation of the findings. The torque vs. angular velocity curves and flow phenomena were found to depend on the mass concentration of the suspension, the gap width between the rotor and housing, and the air content of the suspension. With little gas present, the flow initially involved tangential flow in an active cavity whose radial extent increased with increasing angular velocity. When the flow reached the outer baffles, a marked flow transition occurred, probably explaining what has been called “fluidization” by Gullichsen and Harkonen (1981). As the gas content of the suspension increased, the gas congregated around the rotor, impeding the transfer of momentum to the suspension. The apparent viscosity of a 10% by mass suspension was of the order of 16 Pa · s under the test conditions.
Hydrodynamic entrance lengths of non‐newtonian laminar falling films
Authors: Li Ruokang 
Published: March 2009

AbstractThe Carreau viscosity model of the shear deformation is used to determine the hydrodynamic entrance length for falling liquid films emerging from a flat slit and flowing in a laminar fashion along an inclined flat plate. The present work enables the entrance‐length problem to be treated in a general form by choosing different values of the two parameters in the model. It is found that a significant difference exists between predicted results based on the power law model and the Carreau model when the fluid is pseudoplastic and the flow is decelerating.
Prediction of the maximum spoutable bed height in spout‐fluid beds
Authors: Grbavčić Ž. B. , Hadžismajlović Dž. E. , Garić R. V. , Vuković D. V. , Littman H. 
Published: March 2009

AbstractA model for predicting the ratio of the maximum spoutable bed height in a spout‐fluid bed to the maximum spoutable bed height in a spouted bed is presented and experimentally verified. The model is a further extension of the basic Mamuro and Hattori force balance model. The ratio HmSF/Hm is found to be a function of the external annular fluid flowrate and a parameter C, which is the ratio of fluid velocity at the top of the annulus to that at minimum fluidization. C = 0.935 gives a best fit of our data.
Growth characteristics of a Bombyx mori insect cell line in stationary and suspension cultures
Authors: Stavroulakis Dimitrios A. , Kalogerakis Nicolas , Behie Leo A. , Iatrou Kostas 
Published: March 2009

AbstractThe growth characteristics of the BM‐5 insect cell line of Bombyx mori (silkworm) have been experimentally investigated in order to develop optimal growth protocols when these cells are used to produce large quantities of biopesticides or human proteins by recombinant baculoviruses. Experiments were performed in 2 mL wells and 200 mL spinner flasks. Spinner flasks were operated at 80 rpm with 0.3% methyl cellulose (MCL) added to the medium in order to protect the cells from liquid shear stress. In addition to the effect of agitation rate and amount of MCL added to the medium, the cell response during the adaptation to growth in suspension from stationary cultures is reported. Exposure of the cells to varying nutrient and metabolite concentrations is accomplished through batch and repeated‐batch modes in 2 mL wells. The results imply that glutamine is a limiting nutrient and lactate has an inhibitory effect on cell growth. Ammonia depletion from the medium was accompanied by uric acid accumulation, suggesting that ammonia is converted to this metabolic product by the “uricotelic” and “nucleicolytic” metabolic pathways.
Control of mass transfer and hydrodynamic holdup in a karr solvent extraction column
Authors: Camurdan M. C. , Taylor P. A. , Baird M. H. I. 
Published: March 2009

AbstractThis paper reports an experimental application of multiloop control to a Karr solvent extraction column (a reciprocating plate column). The control objective was to keep the extract outlet concentration above some minimum level and to maintain a high value of dispersed phase holdup while keeping away from the flooding point. Transfer function models were identified from step tests about a nominal operating point and various interaction/operability analysis techniques were used to synthesize a control scheme. The control implemented in this study was a model inversion based scheme in which the extract outlet concentration was controlled by manipulating the continuous phase superficial velocity and the dispersed phase holdup was controlled by manipulating the frequency of reciprocation. Both servomechanism and regulatory responses are presented. A variable dead time Dahlin controller was used to control the extract outlet concentration and a Clarke‐Gawthrop self tuning regulator was used to control the dispersed phase holdup. This multiloop control scheme is compared to single loop control of the extract outlet concentration.
Performance of two heat transfer fouling probes for various fluids
Authors: Steinhagen H. Müller , Branch C. A. 
Published: March 2009

AbstractThe predictions of two commonly used fouling monitoring devices, namely a heated rod in an annulus and a coiled wire in cross‐flow are compared. As fouling fluids, heptane with dissolved styrene (to simulate chemical reaction fouling), heptane with suspended particles (to simulate particulate fouling) and Kraft pulp black liquor (where both the above fouling mechanisms may occur) have been used.