bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transferts thermiques entre un serpentin et des fluides newtoniens ou non—newtoniens agités par une turbine à pales inclinées dans une cuve
Authors: Desplanches Herve , Llinas J. Richard , Chevalier Jean‐Louis 
Published: March 2009

AbstractLe travail présenté concerne le transfert thermique entre un septentin hélicoïdal et des liquides newtoniens, ou non‐new‐toniens agités par une turbine à 4 pales inclinées dans une cuve cylindrique.La viscosité effective des fluides rhéofluidisants est définie par le modèle de Metzner‐Otto combiné à l'équation rhéolo‐gique d'Ellis. Le transfert thermique dans les fluides newtoniens en régime turbulent est représenté avec la meilleure précision par les équations:

Dans le domaine non‐newtonien, en pompage bas, l'équation ci‐dessous permet une estimation très précise du coefficient d'échange thermique en régime d'établissement
Experimental studies of a consecutive—competitive reaction in steady state and forced periodic CSTRs
Authors: Lee C. K. , Yeung S. Y. S. , Bailey J. E. 
Published: March 2009

AbstractExperimental studies of diethyl adipate saponification in a CSTR show that forced cycling of feed composition produces significant yield increases in intermediate product relative to the optimal steady state operation, while forced temperature cycling has much less effect. Related experiments provide useful transient heat transfer data for this system. Reaction kinetics have been determined in water and in a 50% (v/v) isopropanol solvent.
The nature of the active sites in the catalytic cracking of gas—oil
Authors: Borodzinski A. , Corma A. , Wojciechowski B. W. 
Published: March 2009

AbstractThe kinetics of gasoil cracking over an HY zeolite catalyst have been studied at atmospheric pressure and temperatures of 482°, 503° and 524°C, using a fixedbed integral reactor. The total conversion of gas‐oil, the yield of gasoline, of various gaseous products, and the influence of temperature on conversion, gasoline and minor product yield are presented here.The various primary reaction rate constants, the constants describing the decay of catalyst activity, and the refractoriness of the feed, have been determined for this system and are compared with those obtained using a LaY zeolite catalyst. The observed differences between these two catalysts are discussed in terms of the nature and number of active sites present on the two catalysts.We conclude that the initial reaction of a saturated gas‐oil feed occurs on a range of Lewis acid sites of various strengths. Such sites are more numerous on LaY than on HY, and this disparity is larger for weak sites than it is for strong sites.
Gasification reactions of chars and modified chars produced from jack pine bark
Authors: Ross Robert A. , Fikis David V. 
Published: March 2009

AbstractChars produced from locally grown jack pine have been gasified at atmospheric pressure with temperatures up to 650°C in a flow reactor. The gases produced were CO, CO2, CH4 and H2 as well as H2 O. Above the char preparation temperature, 350°C, the yields of gaseous products increased with temperature until 550−600°C when the production of CH4, CO and H2 O decreased. Chars modified by the separate inclusion of 1% w/w sodium borate, sodium phosphate and nickel oxide produced changes in the product distribution; an effect which was also studied during the addition of steam to the gasification cycles. Gross calorific values of the chars and allied materials were determined in an adiabatic bomb calorimeter and residues were analysed for C, H and N contents.
Caractérisation de la tourbe pour le traitement des eaux usées d'abattoirs
Authors: Gravelle Denis V. , Landreville Alain 
Published: March 2009

AbstractFace à la nécessité de trouver un procédé efficace pour le traitement des eaux usées d'abattoirs, une étude fut menée dans le but d'utiliser la tourbe de sphaigne comme agent d'épuration. Des essais de sorption à l'équilibre et en mode continu à l'aide de solutions synthétiques et industrielles confirment que toute modification chimique apportée à la tourbe n'améliore pas le rendement de celle‐ci face à la retenue des substances organiques retrouvées dans ces eaux. Cette étude vise à identifier les caractéristiques permettant de réduire la concentration des substances organiques au même ordre de grandeur que celle que l'on retrouve dans une eau usée domestique. Les essais en continu, sur des unités pilotes à lit fixe et à lit mobile, démontrent que la tourbe naturelle peut diminuer de façon appréciable la demande totale en oxygène des eaux usées d'abattoirs.
Biodegradation of high—yield spent bisulfite pulping liquor in two volume‐varied chemostats in series
Authors: Lo S. N. , Valade J. L. 
Published: March 2009

AbstractSpent liquor from industrial high‐yield bisulfite pulping was biodegiaded in a 20‐litre reactor system consisting of two unequal chemostats in series. The purpose was to study, for a fixed total volume, the variation of the overall biodégradation performance with the volume ratio of the first chemostat to the system, especially focusing on the occurrence of maximal % BOD5 removal.Values of kinetic parameters (substrate removal rate constant, coefficients of decay and growth, and non‐biodegradable matter in feed) obtained for each chemostat were found to be different. Overall % BOD5 removals were 62 to 73 for the operating conditions studied; the maximum occurred at a volume ratio equal to 0.8. Experimental findings agreed very well with calculated theoretical values. In both chemostats, experimental % BOD5 removal decreased linearly as BOD5 loading increased. Excellent correlation existed between % removals of BOD5 and carbohydrates.
Dynamics of a trickle—bed hydrocracker with a quenching system
Authors: Yan T. Y. 
Published: March 2009

AbstractA mathematical model has been developed to simulate the dynamic behavior of a trickle‐bed hydrocracker without and with one quench. The model was used to study the effects of parameters on transient temperature and hydrocarbon feed profiles. The system was found to be very sensitive to inlet temperatures and the states of catalyst activity.The model can be used to guide design and operation of a quenching system, i.e., proper location, starting time, and quantity of quench stream, to prevent excess temperature rise that would otherwise lead to “run‐away” condition and poor product yields.
The onset of droplet entrainment in annular downward flows
Authors: Andreussi Paolo 
Published: March 2009

AbstractThe point of onset of large disturbance waves and droplet entrapment has been determined for the annular downward flow of air‐water mixtures in a 24 mm ID tube.Experimental results are in a good qualitative agreement with the previous work by Webb and Hewitt1. These results indicate that

the critical gas velocity at the onset of entrainment is lower than the value predicted by available correlations
the critical gas velocity continuously decreases at increasing the liquid Reynolds number
below a liquid Reynolds number of 270 no entrainment occurs even at gas velocities as high as 80 m/sec

A correlation for the critical gas velocity which is based on a simple physical model of atomization, is also proposed.
An experimental study on solid‐liquid flow through rectangular ducts
Authors: Prasad Nawal K. , Chand Prem , Mirajgaokar A. G. 
Published: March 2009

AbstractReduction in energy consumption has been the main concern of the workers in the field of solid‐liquid flow. Investigators have tried to achieve this objective in various ways. Two of the well‐known methods are: the addition of polymer solutions to the solid‐liquid mixture and the fitting of helical ribs inside regular circular pipes. In the latter case, the reduction is considerable, but it results in a very low rate of transportation. Chiu and Seman have reported considerable reduction of head loss in a square duct when compared to the flow through a circular pipe.In the present work, an experimental study has been underaken to compare the head loss for solid‐liquid flow in a circular pipe, with that for rectangular ducts of four different aspects ratios (width/height ratios), keeping the cross‐sectional area of each one of them to be the same. When the perforance of a circular pipe is compared with that of the other rectangular ducts, it seems that the square duct shows a better performance in the low operating range of velocity, whereas the rectangular duct of aspect ratio 1.5 presents a still better performance, from the energy requirement point of view, for practically the entire velocity‐range within which the experiment was conducted.
Terminal velocity of porous spheres
Authors: Masliyah Jacob H. , Polikar Marcel 
Published: March 2009

AbstractTerminal velocity of porous spheres was experimentally measured for a Reynolds number range of 0.2 to 120 for anormalized sphere radius, β = R/R of 15.6 to 33, where R and k are the sphere radius and permeability, respectively. The drag coefficient for 15 < β < 33 was found to be CD = 24Ω/Re [1 + 0.1315 Re(0.82 ‐ 0.05w)] for 0.1 < Re ≤ 7 and CD = 24Ω/Re [1 + 0.0853 Re(1.093 ‐ 0.105w)] for 7 < Re < 120 with w = log10Re where Re is the sphere Reynolds number and Ω=2β2 [1 ‐ (tanh β/β)] / 2β2 + 3[1 ‐ tanh β/β)]At high Reynolds numbers, it was found that the porous sphere terminal velocity was less affected by the container walls than for the case of an impermeable sphere. However, at very low Reynolds numbers, the wall effects were found to be similar for both the permeable and the impermeable spheres.
Heat transfer of evaporating droplet flow in low pressure systems
Authors: Rane Anil , Yao Shi‐Chune 
Published: March 2009

AbstractConvective heat transfer of laminar droplet flow is analyzed for a low pressure system, where latent heat of evaporation and ratio of liquid density to vapor density is high (for example, water at l atm). The droplet size is considered to be approximately constant but the vapor velocity is considered increasing along the tube. The heat transfer effect of droplets in the vapor stream is treated as distributed heat sink. Results are presented in non‐dimensional form for circular tubes, with constant wall heat flux or constant wall temperature boundary conditions. Distinct heat transfer behavior of droplet flow is revealed.
Decomposition of t‐butyl acetate on charcoal and comparison with isomers on charcoal and in the gas phase
Authors: Pettit Paul J. , Anderson Robert B. 
Published: March 2009

AbstractThe decomposition of t‐butyl acetate on charcoal to isobutene and acetic acid is a clean, zero‐ordet reaction at temperatures of 151° to 288°C with an apparent activation energy of 90.8 kJ/mol. The rates for the 4 butyl acetates on charcoal and in the gas phase are compared. The rates on charcoal are always larger than those in the gas phase. The primary reaction products from the decomposition on charcoal and in the gas phase are acetic acid and the butene indicated by the six‐center‐ring mechanism.
Pitch and petroleum coke additions to coke oven charges
Authors: Price J. T. , Gransden J. F. , Leeder W. R. 
Published: March 2009

AbstractSeveral pitch materials and a petroleum coke were added to coke oven charges in an attempt to make good metallurgical coke from Canadian coal of poor coking quality. Coal and petroleum pitches were added to a low fluid western Canadian coal of medium volatile bituminous rank, and the blends coked in a technical‐scale moveable wall test oven having a 230‐kg charge capacity. Pitches improved coke tumble test indices, the principal coke quality parameter related to blast furnace performance. Varying levels of petroleum coke were added to an eastern Canadian coal of high volatile bituminous rank, and the blends, some partially briquetted, were carbonized in a test oven. Tumble indices of coke from the partially briquetted charges approached an acceptable level. These investigations confirm that petroleum products as well as coal derivative can play a useful part in the production of a metallurgical strength coke from poor or non‐coking coals.
The use of krasovskii's stability technique for control strategy evaluation and system design
Authors: Lee P. L. , Newell R. B. 
Published: March 2009

AbstractKrasovskii's stability method for generating Lyapunov functions for the prediction of regions of asymptotic stability (RAS) is applied to a second‐order chemical reaction in an adiabatic CSTR. Three conclusions are drawn from this study. Firstly, that the stability areas predicted by the method are too conservative for use as criteria for control system design. Secondly, that the method fails to predict valid regions of asymptotic stability under some circumstances. Thirdly the results are shown to be sensitive to changes in system parameter values.
A new theoretical formula for turbulent heat and mass transfer with gases or liquids in tube flow
Authors: Sandall O. C. , Hanna O. T. , Mazet P. R. 
Published: March 2009

AbstractA new theoretically‐based formula is presented for fully developed steady‐state forced convection heat or mass transfer in turbulent tube flow. This relationship, which is proposed for the frill range range of Prandtl or Schmidt numbers between 0.7 (gases) and 100 000 (liquids), is as follows:

Coniparisons a with widely quotcd sets of data show very good agreement IFriend and metzner (heat transfer in liquids), Dcisser and Eian (heat transfer in air), Allen aid Eckert (heat transfer in water), Malina and Sparrow (heat trniisfcr in liquids), Harrott and Hamilton (mass transfcr in liquids)]. Absolute mean deviations vary from 3.6 to 8.1% over the range 0.73 + Pr or Sr ≤ 97 600.
An analytical model for the combustion of coal particles
Authors: Shadman Farhang , Cavendish James C. 
Published: March 2009

AbstractA model for the combustion of coal particles is developed which accounts for the gasification and pyrolysis reactions throughout the particles, oxidation reactions at the particles' outer surface, distributed gas‐phase reactions around the particles, and transport of heat and mass throughout the reaction zones. The model shows that the combustion of large particles is dominated by gasification and gas‐phase reactions. As large particles burn and shrink, however, the mechanism changes to one dominated by surface oxidation. This change in mechanism can be gradual or very rapid (even discontinuous) depending on the combustion conditions. The particle size at which this transition takes place decreases as the bulk gas temperature or oxygen concentration increase. The proposed model is used to predict the conversion of pulverized coal as a function of time; the results agree with literature data for particles of 26‐32 μm radius.
Determination of the heat of some aerobic fermentations
Authors: Luong J. H. T. , Volesky B. 
Published: March 2009

AbstractAn accurate technique has been developed and applied to continuous measuring of the rate of heat production during a fermentation process. A special temperature control system was developed and used to monitor the heat quantity. The results were corrected for heat losses and gains based on the overall heat balance on the fermentor. The technique was used for precisely determining the rate of heat evolution of Aspergillus niger, Escherichia coli, Candida Upolytica, Candida intermedia and Candida utilis grown on etlianol and different carbohydrate and hydrocarbon sources.Based on the experimental data, a correlation between the rate of heat released and the rate of oxygen consumed has been determined as Qterm = 0.465 MJ/mol O2 · Δ02. The total heat released also correlated well with the total oxygen consumed by the growing culture. The proportionality constant for this correlation was 0.461 MJ/mol O2. The experimental results agreed well with the theoretical predictions and with those developed by the dynamic calorimetric technique.The derived correlations reported in this study arc useful for fermentation process design, optimization and control as well as indicators of microbial metabolic activity.
Electrolysis in a pilot‐plant size cell using inclined electrodes and non‐uniform magnetic fields
Authors: Ismail M. I. , Fahidy T. Z. 
Published: March 2009

AbstractThe effect of the inclination angle between opposite electrodes, and between parallel electrodes and the vertical and the horizontal axis, on natural convectivc ionic mass transfer and deposition pattern at inclined vertical plate electrodes was studied in a pilot‐plant scale magneoelectrolytic reactor. The non‐uniform magnetic field with a maximum gradient at the centre of the reactor was generated by means of solenoid winding of water‐cooled copper pipes and high‐current cables. Copper was deposited from an aqueous solution of cupric sulfate and at ambient temperatures on a stainless steel cathode placed at various angles in the horizontal and vertical direction with respect to a stainless steel anode of identical size. Mass transfer rates, inclination angle and bubble pattern are strongly interrelated. The rate of gas generation at both electrodes as well as induced magnetohydrodynamic turbulence determine the extent of locally strong mixing in the cell. The extent and position of cathode oxide formation, due to anodically generated oxygen is influenced by the distribution of the magnetic and the electric field in the cell.
Liquid flow over a rotating dip coater
Authors: Nigam K. D. P. , Esmail M. N. 
Published: March 2009

AbstractThe hydrodynamics of a Newtonian fluid entrained from a stagnant pool by a rotating, partially immersed horizontal cylinder is considered. A numerical solution, based on the Galerkin method of weighted residuals, predicts the film thickness variation over the cylinder surface. The results are compared with experimental measurements and theoretical predictions available in literature. The comparison with the experimental data is good, especially for high capillary numbers. This supports the claim that inertia effects are better depicted in a nonlinear treatment of the problem. The computational procedure applied is not complicated, and may be used for industrial predictions.
The relevance of “HLB” to de‐emulsification of a mixture of heavy oil, water and clay
Authors: Cooper David G. , Zajic J. E. , Cannel Edward J. , Wood Joan W. 
Published: March 2009

AbstractSeries of synthetic neutral surfactants have been used to break emulsions of heavy oil, water and clay. The degree of de‐emulsification was found to correlate with the hydrophilic‐lipophilic balance (HLB) of the surfactant. The most effective agents for de‐watering had HLB values between either 4 and 6 or 13 and 15. For clay removal, the most useful surfactants had HLB values above 20. Surfactants between 5 and 8 were also effective for removing clay, but the material released had appreciably more oil adhering than that removed by the higher HLB compounds. Other surfactant parameters such as surface tension, interfacial tension against hexadecane and spreading tension were unrelated to de‐emulsifying ability.
Transient behavior of the oxidation of propylene over a modified silver oxide
Authors: Kobayashi Masayoshi 
Published: March 2009

AbstractThe oxidation of propylene over a silver oxide containing sodium chloride and sodium hydrogensulfate has been studied by using a transient response method at temperatures ranging from 150 to 175°C. An overshoot behavior for the transient response of propylene oxide indicates the mechanism of Eley‐Rideal type with a rapid desorption of propylene oxide and a slow regeneration of surface oxygen. The activation energy estimated at the transient state was 58.6 kJ/mol.A characteristic S‐shape mode for the transient response of carbon dioxide reveals the presence of a stable intermediate (In). The (In) can produce equimolar amounts of H2O and CO2 by the reaction with oxygen without producing propylene oxide, indicating that the ratio of C:H in the structure of (In) is 1:2. The amount of (In) estimated under the steady state of reaction is a linear relation to the rate of CO2 formation. The estimated apparent rate constant for the formation of CO2 is in good agreement with that for (In) decomposition estimated from the transient response curves of (In) decomposition. From this agreement, it is concluded that the (In) is a reaction intermediate through which carbon dioxide and water are produced.
Simulating the effects of mixing on the performance of unpremixed flow chemical reactors
Authors: Ritchie Ben. W. 
Published: March 2009

AbstractA parallel three environment model is developed to describe the effects of incomplete mixing on the performance of continuous flow chemical reactors fed separately by feedstreams which may have arbitrary flowrate and arbitrary residence time distribution. Unpremixed reactants are assumed to first enter partially segregated entering environments and subsequently transfer to partially mixed leaving environments at a rate and in amounts defined by an environment transfer function. Mixing in the environments is stimulated stochastically by Monte Carlo techniques. Calculations based on a kinetic model of the Michaelis‐Menten type for arbitrarily selected pairs of residence time distributions suggest that performance is strongly influenced by the degree of overlap of the distributions and the method of feeding the reactants. The model is shown to compare directly with published experimental data obtained from a “jet‐stirred” reactor and an equivalence found between the models' parameters and those of previously developed micromixing models.
Prediction of the viscosity of mixed electrolyte solutions from single‐salt data
Authors: Nowlan Maarie‐France , Doan Thi Hoa , Sangster James 
Published: March 2009

AbstractThe viscosities of sonic mixed electrolyte solutions (NaCl + KCl, NaCl, + Nll4NO3, NaCl + CaCl2, NaCl + Ca(NO3)2, NaCl + MgSO4) have been measured to high concentration at 298 K. Existint: viscosity data for the single‐salt solutions have been fitted, as required, to Goldsack's two‐parameter equation. Mixed electrolyte data have been used to test the predictive accuracy of five simple methods of estimation. The usefulness and relative accuracies of the methods have been discussed briefly.
In‐situ volume fraction determination in multi‐component mixtures using pulsed nuclear magnetic resonance
Authors: Abouelwafa M. S. A. , Kendall E. J. M. 
Published: March 2009

AbstractA simple method of determining in‐sitn volume fractions in multiphase or multi‐component systems using pulsed nuclear magnetic resonance is proposed and discussed from both the theoretical and experimental point of view. A 180° ‐ τ ‐90° pulse sequence was employed. Different mixtures were examined both analytically and experimentally and the results compared.
Drag reduction by fibers
Authors: Sharma R. S. 
Published: March 2009

AbstractDrag reduction in turbulent pipe flow by means of boundary and centerline injection of long hair‐like asbestos fibers has been investigated. Pressure drop and mean velocity profiles were measured at various Reynolds numbers and injection rates in order to study some mechanistic aspects of drag reduction in water‐fiber and polymer‐fiber systems. Drag reduction in a water‐fiber system is attributed to a decrease in the momentum transfer in the turbulent‐core region, whereas synergism has been found to be a wall phenomenon.
Étude théorique et expérimentale de la formation d'une couche Limite par convection libre dans une eau à basse température
Authors: Vasseur P. , Robillard L. 
Published: March 2009

AbstractA study, both analytical and experimental, has been made on the natural convection induced by an isothermal vertical plate immersed in a large volume of water at a temperature which was close to its freezing point. A particular attention has been paid to the effects resulting from the non‐linearity existing between the density of water and its temperature. when the latter was close to 4°C. The plate temperature (Tw) was in the range from 8.0°C to 27.2°C. while the water temperature (Ti) varied between 0°C and 22.2°C. The Prandtl numbers for the flow were in the range from 6.4 to 13.7. An excellent agreement between the theoretical solution and the experimental data has been observed.