bluuebunny/crossref_metadata_2025_split huggingface dataset:
Etude numérique de l'évaporation dans un courant d'air humide laminaire et turbulent d'un film d'eau ruisselant sur une plaque inclinée
Authors: Mezaache El Hacene , Daguenet Michel 
Published: May 2010

AbstractEn utilisant, pour le film, des équations de transfert unidimensionnelles, partiellement bidimensionnelles et bidimensionnelles, les auteurs déterminent le modéle qu'il convient d'adopter selon les conditions thermiques imposées à la parol. lls comparent leurs résultats à ceux d'autres travaux et étudient l'influence du débit massique du film liquide et de l'inclinaison. Its montrent que le transfert de chaleur est dominé par le transfert lié à la transition liquide‐vapeur et que la contribution de la chaleur sensible n'est significative qu'au niveau de la région turbulente oú la température et la densité du flux de vapeur sont quasi constantes et l'épaisseur du film liquide uniforme. Le débit et l'inclinaison sont sans influence sur les transferts lorsque la paroi est adiabatique. Pour une parol isotherme ou à densite de flux de chaleur imposée, le débit influence essentiellement la région turbulente en réduisant la température de l'interface et les coefficients de transferts de chaleur et de masse. L'inclinaison affecte principalement la région laminaire; elle accroit la vitesse d'écoulement du film, réduit son épaisseur et agit peu sur les coefficients de transfert.
A low reynolds number k‐ϵ modelling of turbulent pipe flow: Flow pattern and energy balance
Authors: Thakre Shirish S. , Joshi Jyeshtharaj B. 
Published: May 2010

AbstractThe present paper addresses a comparative analysis of twelve different versions of low Reynolds number k‐ϵ turbulence models. The predictive capability of the models have been tested on the basis of the flow patterns and energy balance. Numerical simulations were performed at the Reynolds numbers of 7400, 22 000 and 500 000. The predicted mean axial velocity and turbulent kinetic energy were compared with the experimental data of Durst et al. (1995) and Schildknecht et al.(1979) for the Reynolds number of 7400 and 22000 respectively. The overall energy balance was established at three Reynolds numbers of 7400, 22 000 and 500000. A comparison of all the models has been predicted.
The solubility of SO3 and sulfuric acid in acetone and MEK
Authors: Won Wooyoung , Hudgins Robert R. , Lohi Ali , Silveston Peter L. 
Published: May 2010

AbstractSolubility experiments undertaken between 18°C and 24°C showed that solubility of SO3 in either acetone or methyl ethyl ketone (MEK) is very small. On the other hand, with these solvents sulfuric acid is fully miscible up to a volume ratio of 30:200 acid:solvent.
The influence of pH upon the hydrolysis of carboxymethylcellulose with cellulases from Trichoderma reesei
Authors: Rodríguez V. Bravo , Dueñas M. P. Páez , Requena A. Reyes , El‐Hadj M. Aoulad , López A. I. García 
Published: May 2010

AbstractWe have studied the enzymatic hydrolysis of carboxymethylcellulose (CMC) with Celluclast, a commercial preparation of cellulases deriving from Trichoderma reesei, by monitoring the variation in the concentrations of glucose and reducing sugars at a constant temperature of 50°C and different pH values. We determined both glucose and overall yield, concluding that the production of glucose directly by endoglucanase is higher than that coming from the hydrolysis of cellobiose by β‐1,4‐glucosidase and that the rate at which cellobiose is formed can be calculated via kinetic parameters that are due in the end mainly to exoglucanase activity. We observed the effect of pH upon the kinetic parameters and found that the ideal value for the hydrolysis of CMC is one of pH 4.9.
A review of techniques for instrumentation design and upgrade in process plants
Authors: Bagajewicz Miguel 
Published: May 2010

AbstractThis article is a review of the area of optimal instrumentation location in process plants for both grassroots designs and upgrades. Emphasis is put in methods for monitoring purposes and based on the cost minimization model. These methods are mostly related to data reconciliation paradigms and include especial consideration to the detection of gross errors. Connections between this model and other models based on other objective functions and goals are analyzed. Finally, the emerging field of sensor design for efficient process fault detection is briefly covered.
A simple and effective model for cross‐flow microfiltration and ultrafiltration
Authors: Makardij Anais (Alice) A. , Farid Mohammed M. , Chen Xiao Dong 
Published: May 2010

AbstractA semi‐theoretical unsteady‐state model for the flux in cross‐flow microfiltration and ultrafiltration has been developed. The model predicts fouling behaviour for a wide range of particle sizes and foulant concentrations. The developed model uses only two coefficients, k1 and k2, incorporating both the influences of the cake formation and the shear cleaning of the membrane, to describe flux decline. These two parameters were found to be almost independent of the operating conditions. The model provides both a fundamental understanding of the key physical phenomena governing flux decline and a rational basis for the design of an improved and modified cross flow filters.
Axial distribution of solids holdup for both hydrophilic and hydrophobic particles in three‐phase fluidized beds
Authors: Zhang Ji‐Yu , Lin Cheng , Lin Chun‐Shen 
Published: May 2010

AbstractThe axial concentration distribution of the hydrophilic and hydrophobic particles, corresponding to poor and good attachment to rising bubbles in water, was investigated in a gas‐liquid‐solid fluidized bed. The sedimentation‐dispersion model depicted satisfactorily the axial distribution of solids holdup by modifying only the terminal settling velocity, which considered the effect of an additional drag force resulting from the attached rising bubbles. This model explained correctly the different phenomena, i.e. solids holdup decreased with increasing the axial height in the non‐attached system, but increased in the attached system.
Prediction of gas hold‐up in a bubble column filled with pure and binary liquids
Authors: Syeda Sultana R. , Afacan Artin , Chuang Karl T. 
Published: May 2010

AbstractA dimensionless correlation for gas hold‐up in a bubble column filled with pure liquids and binary mixtures has been developed. The criteria of bubble coalescence in pure liquids and foamability of binary mixtures have been included successfully in the proposed correlation. For the first time, comprehensive data of gas hold‐up with respect to concentration in four binary systems are presented. The often‐reported enhancement of gas hold‐up in aqueous alcohol mixtures has been observed experimentally. The proposed correlation is able to predict successfully the trend of gas hold‐up enhancement with respect to concentration. The estimated values are found to be within 7% of the measured values.
Kinetics of the photocatalytic total oxidation of different alkanes and alkenes on TiO2 powder
Authors: Kleinschmidt Olaf , Hesse Diethard 
Published: May 2010

AbstractAlthough photocatalyzed total oxidation reaction of hydrocarbon species has been discussed in the literature, most of these studies were performed to obtain an appropriate reaction mechanism. Studies on the kinetics of this type of reaction are rare. Using titanium dioxide as the photo catalyst, the kinetics of the total oxidation of methane, ethane, ethene, as well as propene, have been investigated using a continuous‐stirred tank reactor. In the experiments, the hydrocarbon concentrations, the oxygen concentration, and the irradiation intensity were varied. The results obtained are evaluated on the basis of a kinetic model to derive rate equations which can be used for reactor design.
Analysis of flux decline during ultrafiltration of sugarcane juice (Limed) using cross flow cell
Authors: Gopal Uppaluri V. S. Rama , Verma Nishith , Bhattacharya Prashant K. 
Published: May 2010

AbstractExperimental and theoretical studies were carried out to analyse the flux decline behaviour of limed sugarcane juice and retention characteristics of its components (total dissolved solids, sucrose and colour) in a rectangular cross flow ultrafiltration cell. Retentions of sucrose and total dissolved solids were found to increase with increase in pressure and feed bulk concentration. A theoretical model was developed to describe flux decline, combining the effects of formation of a gel‐like porous layer (constituting high molecular weight substances) and osmotic pressure controlled layer (constituting low molecular weight substances). Predictions were observed to be in good agreement.
An apparatus for the measurement of surface tensions at high pressures and temperatures
Authors: Millette Jacques P. , Scott Donald S. , Reilly Irvine G. , Majerski Piotr , Piskorz Jan , Radlein Desmond , Debruijn Theo J. W. 
Published: May 2010

AbstractAn apparatus for the measurement of surface tensions of organic liquids in contact with a gas has been developed which is capable of operation to 400°C and to 14 MPa. It is based on the maximum bubble pressure technique, modified for hydrocarbon oils at high pressures and temperatures. Accuracy of measurement is of the order of ±3% for non‐aqueous systems for values down to 5 mN/m. Only a 20 to 30 mL liquid sample is required, and small gas volumes. In practice, it was found that measurements with most organic liquids could only be made to a maximum of about 350°C because of the thermal instability of most of these compounds, in particular, for hydrocarbon liquids. Any thermal decomposition or coke deposition leads to inaccurate results. Results obtained for known liquids are compared with values given in the literature.
Gas hold‐up in stirred tank reactors
Authors: Yawalkar Archis A. , Pangarkar Vishwas G. , Beenackers Anthony A. C. M. 
Published: May 2010

AbstractBased on a study of the gas hold‐up data for stirred tank reactor generated in the present work and the data available in the literature for large stirred tank reactors (T = 0.57 m to 2.7 m) equipped with disc turbines and pitched blade downflow turbines a correlation is presented which reliably predicts gas hold‐up data over wide range of system configurations and operating parameters. The parameter used, N/Ncd, relates gas hold‐up at impeller speed N with respect to the gas hold‐up at minimum impeller speed for complete dispersion of the gas, Ncd. It is shown that the gas hold‐up data of different workers when compared on the basis of N/Ncd, shows unanimity.
Bubble characteristics of a scaled‐down three‐phase fluidized bed
Authors: Safoniuk Mike , Grace John R. , Lim Kok‐Seng 
Published: May 2010

AbstractExperiments were carried out in a 0.29 m diameter column to provide information on bubble characteristics relevant to an industrial three‐phase fluidized bed reactor. Using a specially built electrical conductivity probe, together with a series of computer programs to gather and filter the data, local bubble properties (rise velocities, pierced chord lengths, frequencies, and direction of travel) were measured. The data are compared to existing correlations. Since the operating conditions were within the dispersed bubble regime, uniform bubbling was anticipated. However, the actual system indicated considerable non‐uniformity, with individual bubbles, large swarms of bubbles and particles traveling at all angles. As a result, it is shown that bubble rise velocities are not necessarily a good measure of the bubble properties and must be vectorized to provide a good means of estimating gas hold‐up.
Modified volume expansion method for measuring gas holdup
Authors: Meng Annie X. , Hill Gordon A. , Dalai Ajay K. 
Published: May 2010

AbstractA simple, modified volume expansion method, or inclined tube method, is compared to the pressure difference method for determining gas holdup in an airlift bioreactor. The modified volume expansion method could be used for all pneumatic bioreactors where fluid fluctuation is vigorous and visual observation of the continuous phase rise is difficult. The overall gas holdup data measured using the inclined tube method are shown to be very close to overall gas holdup determined using a gamma ray density monitor system. However, the overall gas holdup measured by the pressure difference method is found to be significantly different. This difference is due to energy dissipation in the External Loop Airlift Bioreactor (ELAB) used in this study, which causes the pressure difference method to be incorrect.
Effect of glucose on photocatalytic decolorization of dyes by TiO2
Authors: Kunitou Katsushi , Maeda Shingo , Hongyou Setsuaki , Mishima Kenji 
Published: May 2010

AbstractThe effect of saccharides, such as glucose, on the photocatalytic decolorization of various dyes has been investigated using TiO2 as a photocatalyst in an aqueous solution saturated with nitrogen. An azo dye, such as Orangell, used as a typical dye, was reduced by cleavage of the azo linkage, as evidenced by the production of sulfanilic acid. All of the dyes tested were decomposed with first‐order kinetics. The rate constants of decolorization in the aqueous solution saturated with nitrogen increased with the addition of a saccharide such as glucose. Furthermore, the effect of the reductive saccharides on the photocatalytic decolorization of dyes was quantitatively correlated with their dispersion force. The reaction rate of the photocatalytic decolorization of dyes in the aqueous solution saturated with nitrogen, including glucose, is 7 times that in the solution saturated with oxygen.
Extraction of a dissolved organic contaminant from water into an aqueous surfactant solution across a microporous membrane
Authors: Marx Sarah , Weber Martin E. 
Published: May 2010

AbstractA novel extraction process, aqueous micellar solvent extraction (AMSE), was demonstrated. In ASME an solute is extracted from a wastewater across a microporous membrane into an aqueous surfactant solution containing micelles that solubilize the solute. The membrane retains the surfactant micelles in the aqueous micellar solvent. ASME was carried out in hollow fiber ultrafiltration modules with benzoic acid as the solute and a fatty amine ethoxylate surfactant. Flowing the micellar solvent through the fibers and the wastewater outside gave good extraction and low contamination of the treated water by surfactant. The major resistance to extraction of solute was diffusion across the wall of the hollow fiber.
Improved modelling of the unsteady‐state behaviour of an immobilized‐cell, fluidized‐bed bioreactor for phenol biodegradation
Authors: Onysko Kira A. , Robinson Campbell W. , Budman Hector M. 
Published: May 2010

AbstractThe dynamic response of an immobilized‐cell, fluidized‐bed reactor (ICFBR) to step changes in phenol loading was investigated at 10°C for a pure culture of Pseudomonas putida Q5, a psychrotrophic bacterium. A novel dynamic model was developed and tested to simulate the response of all four key process variables: the bulk phenol concentration, the suspended biomass concentration, the concentration profile of the substrate in the biofilm and the biofilm thickness. Accurate model predictions required the use of kinetics, determined using cells which were not acclimated to the post‐shock reactor conditions (‘unacclimated’ cells) and the implementation of a specific‐growth‐rate suppression factor to account for the unbalanced growth situations experienced during the transient response periods.
Generic model controller tuning for chemical processes with input saturation
Authors: Guo Bingjun , Hua Xiangming , Jutan Arthur 
Published: May 2010

AbstractControl in the face of process input constraints is very common and of great practical importance in the processing industries. Generic Model Control (GMC) is a model‐based control framework for both linear and nonlinear systems. In this paper, a constrained GMC controller tuning approach using a nonlinear least squares technique is proposed. This tuning approach is simple to apply. For a SISO GMC control system with input saturation, the tracking performance is significantly improved by adding a simple heuristic switching strategy. The effectiveness of the proposed controller tuning approach is demonstrated using dynamic simulations and MIMO real‐time experiments.
Prediction of dispersed phase holdup in a modified multi‐stage bubble column scrubber
Authors: Meikap Bhim C. , Kundu Gautam , Biswas Manindra N. 
Published: May 2010

AbstractThis paper reports on the experimental investigation carried out to evaluate fractional dispersed phase holdup for a gas‐liquid mixture in a modified multi‐stage bubble column (with contraction and expansion disks), which has been conceived, designed and fabricated as a wet scrubber for control of air pollution; in addition it has versatile use as a gas‐liquid contactor in chemical process industries. A correlation developed for predicting fractional dispersed phase holdup has been found to be encouraging and highly significant from statistical analysis.
Influence of liquid viscosity and bed porosity on two‐phase pressure drop in concurrent gas‐liquid upflow through packed beds
Authors: Khan Ahamed , Khan Asad Ali , Varma Y. B. G. 
Published: May 2010

AbstractIt was observed in the experimental investigations that the concurrent upflow of air‐Monoethanol amine system through the packed bed gave higher pressure drop in bubble flow regime than the air‐water system. But when the flow regime changed to spray flow, air‐water system showed higher pressure drop than the other. This phenomenon was observed for the two column packing used in this study. An attempt is made to explain this phenomenon.
Pressure drop for single and two‐phase flow of non‐newtonian liquids in helical coils
Authors: Bandaru S. V. S. R. Krishna , Chhabra Rajendra P. 
Published: May 2010

AbstractNew experimental results on pressure loss for the single and two‐phase gas‐liquid flow with non‐Newtonian liquids in helical coils are reported. For a constant value of the curvature ratio, the value of the helix angle of the coils is varied from 2.56° to 9.37°. For single phase flow, the effect of helix angle on pressure loss is found to be negligible in laminar flow regime but pressure loss increases with the increasing value of helix angle in turbulent flow conditions. On the other hand, for the two‐phase flow, the well‐known Lockhart‐Martinelli method correlates the present results for all values of helix angle (2.56‐9.37°) satisfactorily under turbulent/laminar and turbulent/turbulent conditions over the following ranges of variables as: 0.57 ≤ n′ ≤ 1; Re′ < 4000; Rel < 4000; Reg < 8000; 8 ≤ x ≤ 1000 and 0.2 ≤ De′ ≤ 1000.
An optimization model of the operating costs of a fluidized bed steam‐drying plant
Authors: Heinrich Stefan , Ihlow Matthias , Henneberg Markus , Krüger Gerhard , Mörl Lothar 
Published: May 2010

AbstractA model is developed to determine an optimum apparatus geometry and, for given apparatus dimensions, a financially optimal fluidized bed height. The parameters that effect the operating costs are the bed mass, the apparatus diameter and the gas mass flow rate. To implement such cost optimization, a physics‐based mathematical model for describing the thermodynamic processes in fluidized bed steam‐drying is briefly explained and presented. The most important conclusion is not to operate the fluidized bed for a drying process below a certain minimum cost, calculated with the help of the modelling. The problem, when describing the drying process and consequently the mass transfer, is that in the superheated steam drying case studied here, water is evaporated as moisture and withdrawn into an atmosphere of vapor water.
Fundamentals of bitumen coking processes analogous to granulations: A critical review
Authors: Gray Murray R. 
Published: May 2010

AbstractA number of coking processes use hot particles to heat liquid bitumen or petroleum residue to cause cracking reactions. These particles may be mineral or coke solids. Interactions of these particles, in fluid beds, moving beds and other types of contactors, are governed by the liquid films on the particle surfaces. This paper explores the analogy between granulation and coking, and suggests that the key relationships that will govern the behavior of wet particles in coking processes are the Stokes number of the particles, the thickness or the liquid films, and the diameter and surface roughness of the particles. The implications for distribution of liquid feed in the reactor, fouling, and defluidization or bogging are discussed. This analysis suggests experiments that can be performed under non‐reactive conditions with scaled variables in order to study phenomena that cannot be observed in situ in high‐temperature cracking processes.
Extraction of halide quaternary salts in an organic solvent/water system: Hydrodynamics and mass transfer
Authors: Wu Ho‐Shing , Liu Chien‐Bang , Lin Yan‐Hun 
Published: May 2010

AbstractThe hydrodynamic characteristics and mass transfers of halide quaternary salts between two immiscible phases in a stirred membrane permeation cell were investigated. The concentration of quaternary salt, temperature, solvent and the four kinds of halide quaternary salts were evaluated to achieve the extractive optimum condition. The diffusivity, overall mass‐transfer coefficients and individual mass‐transfer coefficients were determined and correlated in terms of the conventional Sh‐Re‐Sc relationship. The transfer time of quaternary salts across the membrane and the thickness of the hydrodynamic diffusion boundary layer were determined as well, so as to characterize the extractive phenomenon of quaternary salts between the two phases that is useful in phase‐transfer catalysis.
A generalized equation for the prediction of melting temperatures of homopolymers and copolymers
Authors: Kamal Musa R. , Feng Lijun , Huang Tao 
Published: May 2010

AbstractA generalized equation was derived to calculate the melting temperatures of homopolymers and copolymers. The Gibbs‐Thomson equation for homopolymers and a modified application to copolymers were derived using the proposed equation. The melting temperature Tm0 in the Flory equation corresponds to the melting temperature TmC,∞ of copolymer crystals with stems of infinite length. Also, TmC,n*, the melting temperature for copolymer crystals with stems containing the maximum possible number of structural units, n*, should be used instead of Tm0 as the basis of supercooling in crystallization. The proposed equation shows good agreement with experimental data for α‐alkene‐ethylene homogeneous copolymers.
Flow‐assisted corrosion of API X‐52 steel in 3.5% NaCl solution
Authors: Amarnath  , Namboodhiri T. K. G. , Upadhyay S. N. 
Published: May 2010

AbstractCorrosion behaviour of API X‐52 grade High Strength Low Alloy (HSLA) steel in 3.5% NaCl solution under flow conditions was studied. Rotating cylinder‐, rotating disk‐ and flat plate‐type rotors were used to observe the effect of rotor geometry. The empirically obtained mass transfer correlations are in agreement with those for standard geometry. An empirical relation between Reynolds number (Re) and weight loss has also been developed for the parallel disk rotor. Scanning electron microscopy of the corroded surface revealed that corrosion proceeds through an initiation of pit‐like regions and their subsequent growth.