bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microcapsule Processing in a Spouted Bed
Authors: Baracat Marcela M. , Nakagawa Adriana M. , Freitas Luis A. P. , De Freitas Osvaldo 
Published: July 2010

AbstractThe aim of this study was to verify the feasibility of drying pharmaceutical microcapsules in a spouted bed with the aid of inert particles. The morphological character and total recovery of the drug model, indomethacin, were compared for spray and spouted bed dried microcapsules. Clusters formed by microcapsules coalescence in the spouted bed showed to have their size dependent on bed height. The total recoveries for three different bed heights were 53.18%, 60.76%, 70.70%, as compared to 95.65% for the spray drying process. The results showed that spouted beds are promising for the preparation of slow‐release drug systems.
Antimony Solubility and Speciation in Aqueous Sulphuric Acid Solutions at 298 K
Authors: Casas Jesús M. , Crisóstomo Gloria , Cifuentes Luis 
Published: July 2010

AbstractThis work is an experimental and theoretical study of antimony speciation and the solubility of Sb2O5, Sb2O3 and Sb2(SO4)3 at 298 K in aqueous sulphuric acid solutions (0 to 6 kmol/m3). A thermodynamic model was developed to quantify the solubility products and aqueous metal speciation. Main dissolved species were H3SbO3(aq) and H3SbO4(aq). The solubility of antimony increases with increasing solution acidity and with the presence of hydrogen peroxide in the solution. The following standard equilibrium constants at 298 K were obtained: Log K0(Sb2O5) = 11.7±0.5, Log K0(Sb2O3) = 32±1, and Log K0(Sb2(SO4)3) = 55±2.
Suggestion of a New Correlation for the Height of Shallow Dispersion Bed Formed in a Rotating Disc Contactor
Authors: Khadiv‐Parsi Parissa , Moosavian Mohammad‐Ali 
Published: July 2010

AbstractA rotating disc contactor (RDC) was designed and constructed. The obtained experimental results for the heights of shallow dispersion beds formed in the separation zone of the extraction column, suggested a new correlation. It was found that any increase in dispersed phase flow rate or rotor speed caused an increase in the dispersion height. Also, the results revealed the profound effect of the continuous phase viscosity on the height of the bed. Within the ranges of experimental results, the proposed correlation was in good agreement with the data of shallow beds compared to previous proposed relations.
LDA Measurements on a Turbulent Gas/Liquid/Fibre Suspension
Authors: Pettersson Johan , Rasmuson Anders 
Published: July 2010

AbstractDetailed continuous phase flow measurements (mean and RMS velocities) by Laser Doppler Anemometry (LDA) of a turbulent gas/fibre/liquid suspension in a rotary shear tester have been performed with simultaneous torque measurements. The model system comprises a refractive‐index matched suspension in the 4‐12% wt. range with gas contents up to 15% vol. The two transition points, found by Andersson and Rasmuson (2000), were detected also with gas present and appear at higher impeller speeds with increasing gas and fibre concentrations. Plotting RMS and mean velocities versus impeller speed and power input, it is found that both decrease with increasing gas and fibre contents.
Some Characteristics of Stirred Vessel Flows of Dilute Polymer Solutions Powered by a Hyperboloid Impeller
Authors: Cavadas A. S. , Pinho F. T. 
Published: July 2010

AbstractMeasurements of the power consumption and mean and turbulent velocities in the wall jet of a stirred vessel flow, powered by a hyperboloid impeller, were carried out. The fluids were aqueous solutions of tylose, CMC and xanthan gum (XG), at weight concentrations ranging from 0.1% to 0.6%, which exhibited varying degrees of shear‐thinning and viscoelasticity. The hyperboloid impeller parameter k of Metzner and Otto (1957) was found to be equal to 27.2 ±4. In the Reynolds number range of 103 to 3 × 104 the mixing power was reduced for all non‐Newtonian fluids, but never by more than 13%. The flows of the 0.2% CMC and 0.2% XG solutions were found to be less turbulent than those of water, especially for the latter fluid where a reduction in axial rms in excess of 50% was found in the wall jet. This was attributed to elasticity effects and especially to the high zero shear viscosity of the latter fluid.
Heat Transfer to an Isolated Bubble Rising in a High‐Temperature Incipiently Fluidized Bed
Authors: Wu Wenyuan , Agarwal Pradeep K. 
Published: July 2010

AbstractVery few experimental data are available on the heat transfer between bubble and emulsion phases; no data are available at high temperatures. The effects of bed particle type and size, bubble size, and bed temperature on the heat transfer coefficient were examined in this experimental and modelling study. The heat transfer coefficient was found to increase to a maximum, and then decrease as the bubble mass increased in the bubble mass range investigated. Increase in bed temperature led to a significant decrease in the heat transfer coefficient. The simple mathematical model developed earlier was extended to include operation at high temperature.
Stability of Homogeneous Fluidization Under Extreme Conditions of Operation
Authors: Foscolo Piero , Gibilaro Larry 
Published: July 2010

AbstractRecently reported results for the behaviour of fluidized beds under extreme conditions of operation are shown to be in good quantitative agreement with the predictions of a long established fluid‐dynamic criterion for the onset of instability of the homogeneously fluidized state. The four sets of experiments relate to fluidization under very high pressure conditions (by supercritical fluids), at very high and very low effective gravitational field strengths, and at very low particle concentrations.
Drying of Suspensions in the Draft Tube Spouted Bed
Authors: Arsenijević Zorana L. J. , Grbavcić Zeljko B. , Garić‐Grulović Radmila V. 
Published: July 2010

AbstractA draft tube spouted bed dryer with inert particles was used for drying suspensions. The effects of the operating conditions on dryer throughput and product quality were investigated. Experiments were performed in a cylindrical column 215 mm in diameter with a draft tube 70 mm in diameter and 900 mm in length. The bed was made of polyethylene particles, 3.3 mm in diameter with a density of 921 kg/m3. The fungicide Zineb, calcium carbonate, calcium stearate and pure water were used as feeding materials. A drying model using the continuity and momentum equations for turbulent accelerating two‐phase flows and conventional rate equations is proposed and discussed. The work is relevant for estimating dryer performance.
Development of Two‐point Dynamic Method for Evaluating Extraction Columns
Authors: Li Hongbo , Tang Xiaojin , Luo Guangsheng , Wang Jiading 
Published: July 2010

AbstractThe steady‐state method by measuring the concentration profile along the column height is an effective way, but it is a time and material consumption method for large extraction columns. In order to investigate the axial‐mixing and mass transfer performances in a large pulsed‐sieve‐plate extraction column with the diameter of 150mm, a two‐point dynamic method with mass transfer based on the diffusion model has been developed. The results proved that the two‐point dynamic method has the advantages of good accuracy, simple boundary equations and flexible sampling position over the traditional single‐point dynamic method. It is a reliable tool for studying the axial‐mixing and the mass transfer performances.
New Approach to Solve a Model for the Effective Solid Stress Distribution in Conical Spouted Beds
Authors: Costa Esly F. , Passos M. Laura , Biscaia Evaristo C. , Massarani Giulio 
Published: July 2010

AbstractCharbel et al. (1999) have investigated the flow stability in conical spouted beds by modeling the effective solid stress distribution in the annular region as a function of the failure state under which the spout‐annulus interface is formed. However, due to the complexity in solving the momentum balance equations for the solid phase, the model application has been restricted to one case. This work is aimed at developing a new methodology to solve this set of algebraic differential equations, using optimization techniques to determine the model parameter. This methodology has improved the model solution extending its application for any other case.
Multiobjective Optimization of Simulated Moving Bed Reactor and its Modification — Varicol Process
Authors: Subramani Hariprasad J. , Zhang Ziyang , Hidajat Kus , Ray Ajay K. 
Published: July 2010

AbstractA comprehensive optimization study on a Simulated Moving Bed Reactor (SMBR) system is reported in this article for the direct synthesis of Methyl Tertiary Butyl Ether (MTBE). In addition, the SMB technology, which is based on synchronous switching of ports, was modified to a new more flexible Varicol process based on non‐synchronous switching. Multi‐objective optimization has been performed for both SMBR and Varicol and their efficiencies were compared. A state‐of‐the‐art optimization technique, viz., Non‐dominated Sorting Genetic Algorithm (NSGA) that allows handling of these complex optimization problems is employed in this study.
Neural and Hybrid Neural Modeling and Control of Fed‐Batch Fermentation for Streptokinase: Comparative Evaluation under Nonideal Conditions
Authors: Patnaik Pratap R. 
Published: July 2010

AbstractFermentations involving competition between two or more kinds of cells under nonideal conditions show complex profiles that are sensitive to the extra‐cellular environment. These fermentations therefore require accurate and rapid on‐line data acquisition and control. However, both on‐line measurements and modelling are difficult and expensive for large bioreactors, thus limiting the usefulness of model‐based control. While neural networks offer an alternative, they require extensive training and can be difficult to optimize for large arrays. Hybrid networks combining a few neural networks with some mathematical equations offer a good compromise. The possibility of using a hybrid model for simulation‐cum‐control has been examined here for the fed‐batch production of streptokinase. Under noideal conditions, hybrid neural models outperformed both mathematical models and arrays of neural networks, thus suggesting their viability for large‐scale fermentation monitoring and control.
Relationship between Riser and Downcomer Gas Holdups in Semi‐batch Circulating Bubble Columns
Authors: Al‐Masry Waheed A. , Al‐Dughaither Abdullah A. , Al‐Samari Turki A. 
Published: July 2010

AbstractGas holdups were measured in a circulating bubble column (CBC) using air‐water system with various additives. The liquid volume in the gas separator affected downcomer gas holdup up to volume ratio equal to 6%. Presence of surface active agents, alcohols, solid particles had little effects on the gas holdups ϵgd — aϵgr relationships. The gas holdups relationships are theoretically related by a single parameter model ϵgd = aϵgr — a + 1, and empirically by two parameter model ϵgd = aϵgr — constant. The theoretical model yielded a values ≅ 0.45, while the empirical model yielded a values ≅ 1.16. Analogy between the two models (Contreras et al., 1998) will lead to incorrect conclusions.
Processibility of Athabasca Oil Sand Using a Laboratory Hyd ro t ransport Extraction System (LHES)
Authors: Wallwork Vince , Xu Zhenghe , Masliyah Jacob 
Published: July 2010

AbstractA novel laboratory scale apparatus has been developed and used to assess the extraction performance of oil sands under conditions analogous to current industrial processes. The apparatus can be used to investigate independently, the liberation of bitumen from the sand as well as air‐bitumen attachment and bitumen recovery. Experiments show that lower operating temperatures have a detrimental effect on bitumen recovery and controlled air addition is beneficial for recovery. The liberation of bitumen from sand grains has been found to proceed faster than air attachment and bitumen recovery, making the flotation the ratelimiting step in the extraction process. The potential benefit of staged air injection into hydrotransport pipelines as a possible process aid is discussed.
A New Device to Determine Bitumen Extraction from Oil Sands
Authors: Luthra Manoj , Lopetinsky Robert J. G. , Sanders R Sean , Nandakumar K , Masliyah Jacob H. 
Published: July 2010

AbstractThe Batch Extraction Unit (BEU) has been in use since the 1970's for studying the extraction of bitumen from oil sand. The present study investigates an alternative method for estimating bitumen recovery, based on visualization of oil sand slurry undergoing digestion. A Couette flow device is loaded with known amounts of oil sand and water. Air is bubbled through the oil sand slurry, while it is subjected to controlled chemical conditions and shear environment. Images of the slurry are captured at various time intervals and then analyzed using image analysis software, which selects black areas based on the gray scale intensities of the area in view. The variation of the black area with time is used as a measure of bitumen recovery. The technique provides quick estimates of final recovery, while enabling kinetic studies of the liberation and recovery processes. The experimental set‐up offers great flexibility in selecting conditions for the digestion of oil sands.
A Two Level Fractional Factorial Design to Test the Effect of Oil Sands Composition and Process Water Chemistry on Bitumen Recovery from Model Systems
Authors: Fong Nelson , Ng Samson , Chung Keng H. , Tu Yun , Li Zaifeng , Sparks Bryan D. , Kotlyar Luba S. 
Published: July 2010

AbstractTo overcome the compositional variability inherent to natural oil sands we use extraction tests with model oil sands (MOS) systems in a systematic, experimental design study. Eight significant variables from screening tests in earlier work are tested here. Namely, concentrations of bitumen, silica fines, sodium kaolinite, illite and montmorillonite. In addition, we tested different concentrations of Ca2+, Mg2+, and Na+ in the synthetic process water used with bitumen separation tests. A two level, fractional factorial experimental design allowed testing of the selected variables using only 16 runs. In addition, sodium hydroxide was added as a ninth variable and four repeat tests allowed evaluation of precision. The resulting bitumen recovery model explained 94% of the data variation. The associated parameter estimates were in general agreement with previous experimental observations and with actual operational experience.
Effect of Temperature on the Stability of Froth Formed in the Recycle Process Water of Oil Sands Extraction
Authors: Choung Jaewon , Walker Justin , Xu Zhenghe , Masliyah Jacob 
Published: July 2010

AbstractThe formation of a stable froth on the top of separation vessels plays an important role in bitumen flotation during bitumen recovery from oil sands. The effect of temperature on the stability of froth using recycle process water employed in bitumen extraction was investigated using a water column. The froth became less stable with increasing solution temperature. Once the solution temperature increased above 50°C, irreversible precipitation of the surfactants present in the recycle process water was observed, resulting in a less stable froth.
Determining Bitumen Viscosity Through Drop Shape Recovery
Authors: Moran Kevin , Yeung Anthony 
Published: July 2010

AbstractIn determining the viscosity of bitumen using conventional methods, the measurements must be conducted at extremely slow shear rates to avoid dissipative heating. In this study, bitumen viscosity is measured at room temperature using a drop shape recovery technique which, as will be shown, is immune to any problem of dissipative heating. The method involves stretching a small droplet of bitumen (and in general, of any viscous liquid) with micropipettes and allowing it to recover to its original spherical shape; the dimensions of the droplet can be as small as several micrometres. The shape recovery process is driven by capillary forces and rate‐limited by the droplet viscosity. As such, knowing the interfacial tension, the droplet viscosity can be determined accurately from the relaxation dynamics. With conventional viscometers, the problem of dissipative heating often increases linearly with the viscosity and quadratically with the shear rate. This is in contrast with shape recovery experiments, where dissipative heating is independent of shear rate and varies inversely with the viscosity.
Hydrogen and Oxygen Bubble Attachment to a Bitumen Drop
Authors: Gu Guoxing , Sanders R. Sean , Nandakumar K. , Xu Zhenghe , Masliyah Jacob H. 
Published: July 2010

AbstractAir bubble – bitumen attachment is a critical step in the flotation of bitumen from mined oil sand. In this study, single bubble – bitumen drop attachment was observed directly using a novel experimental technique. Induction time is determined and used as an indication of bubble‐bitumen attachment potency for both hydrogen and oxygen bubbles. The attachment tests were conducted in deaerated municipal water (City of Edmonton tap water) at temperatures ranging from 22–50°C. Induction times measured for hydrogen bubble attachment were shorter than those for oxygen bubbles. Coalescence tests were also conducted in the absence of bitumen, and showed that hydrogen bubbles coalesced more rapidly than oxygen bubbles in both deaerated municipal water and clear (solids‐free) process water.
Determination of Decompression Wave Speed in Rich Gas Mixtures
Authors: Botros Kamal K. , Studzinski Wojciech , Geerligs John , Glover Alan 
Published: July 2010

AbstractExperimental data on the decompression wave speed of a conventional gas mixture and three other rich gas mixtures with varying C1 from 70 to 82% have been collected. An NPS 2 stainless steel expansion tube test rig has been constructed at TCPL Gas Dynamic Test Facility (GDTF) in Didsbury, AB, Canada, specifically for this task. Decompression wave was generated by a rupture disc at the end of the tube, which was instrumented with eight high frequency response pressure transducers located along the tube. The facility has the following three distinct capabilities: high initial pressures of up to 22 MPa, low initial temperature down to ‐20°C, and flexibility in testing any rich gas mixtures. The decompression wave speed data are presented in terms of the decompression expansion pressure ratio for all four gas mixtures and three initial line pressure of ∼ 10, 14 and 20 MPa. Comparison between experimentally obtained decompression wave speeds and those predicted by GASDECOM is also made for each test.
Mixing Time Studies in Multiple Impeller Agitated Reactors
Authors: Kasat Gopal R. , Pandit Aniruddha B. 
Published: July 2010

AbstractMixing time studies have been carried in a 0.3m diameter and 0.9m tall vessel equipped with three impellers. Conductivity measurement technique has been used for the measurements of mixing time. Effect of the various parameters i.e. tracer density, tracer volume, speed of rotation and impeller combination on mixing time has been studied for two impeller combinations used viz. PTD‐PTD‐PTD and PTD‐PTD‐DT. A compartment model (with one fitted parameter, the exchange flow rate QE) with single compartment per agitation stage has been used to predict the conductivity response and the exchange coefficients are calculated from the model parameter. An attempt has been made to explain the experimental results on the basis of the liquid phase axial dispersion coefficient and cell residence time, calculated from the model parameter QE
Effects of Gas‐Agitation and Packing on Hydrodynamics and Mass Transfer of Extraction Column
Authors: Xiong Jieming , Zhang Liping 
Published: July 2010

AbstractThe effects of gas‐agitation and packing on hydrodynamics and mass transfer were investigated through experiments with air‐kerosene (benzoic acid)‐water system and corrugated‐packing of calendering plate with hole. The holdup of gas, holdup of dispersed liquid phase and mass transfer coefficient increase and the flooding velocity decrease with the increase in superficial gas velocity. Over‐agitation of gas causes over‐dispersion and emulsification of dispersed liquid phase, reduction of mass transfer performance and even flooding. The mass transfer performance of a packed column is far better than that of an unpacked column.
Penetration of Shear Flow Into an Array of Rods Aligned With the Flow
Authors: Davis Anthony M. J. , James David F. 
Published: July 2010

AbstractShear flow over a square array of widely‐spaced rods aligned with the flow is investigated using singularity methods to solve Stokes equation. The flow field is determined for various arrays occupying a fraction of a Couette channel, for solid volume fractions from 0.001 to 0.1. Flow penetration into an array is quantified by the slip velocity at the array edge. This velocity is much greater than when the flow is across the array but still less than the value predicted by the use of Brinkman's equation.
A New Application of the Severity Factor Kinetic Model: Thermal Plasma Treatment of Black Liquor
Authors: Yargeau Viviane , Marcos Bernard , Soucy Gervais 
Published: July 2010

AbstractThe kinetic analysis of the treatment of black liquor by a thermal process can be performed in the conventional overall kinetic approach. However, while the detailed reaction mechanism remains unknown, the experimental analysis of black liquor treatment by submerged plasma demonstrates that the operating conditions (catalyst, plasma gas, temperature…) modify the kinetics and render this approach inefficient. The phenomenological approach based on the severity factor developed for the kinetic analysis of lignocellulose decomposition, is then proposed as an alternative to the conventional approach. The 3‐parameters model is validated for decomposition of formic acid and for sulfur oxidation.
Extraction of Gold (III) Ions from Aqueous Solutions Using Polyamine Type Surfactant Liquid Membrane
Authors: Kargari Ali , Kaghazchi Tahereh , Soleimani Mansoureh 
Published: July 2010

AbstractExperimental results of extraction of gold (III) ions from aqueous solutions by a polyamine type liquid membrane are presented. The effects of various parameters such as concentration of gold ions in the external phase, concentration of carrier, concentration of the internal phase reagents, pH of the external phase and the speed of agitation on the extraction rate were studied. The results show that by proper selection of the extraction conditions, nearly all of the Au (III) ions present in a highly concentrated feed solution was extracted within a few minutes.
Adiabatic Calorimetric Decomposition Studies of 35 Mass% Hydroxylamine Hydrochloride/water
Authors: Cisneros Lizbeth O. , Rogers William J. , Mannan M Sam 
Published: July 2010

AbstractThe HH (35 mass% hydroxylamine hydrochloride/water solution) and HH‐ind (stabilized 35 mass% hydroxylamine hydrochloride/water solution for industrial use) decomposition reaction has an onset temperature of ∼145°C. The measured gas phase decomposition products are 0.25 mol N2 and 0.06 mol O2 per mol of hydroxylamine hydrochloride with small quantities of N2O and H2, and a trace amount of NO for a total noncondensable gas production of ∼0.39 mol/mol of hydroxylamine hydrochloride. The reaction system is tempered by the evaporation of the solvent (water) and the reaction is drastically catalyzed by stainless and carbon steel.