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International Review of Chemical Engineering (Rapid Communications) - September 2012 (Vol. 4 N. 5) - Papers




         Open Door Initiative (ODI) (3rd edition)







International Review of Chemical Engineering (Rapid Communications) - Papers


go to top   Using a Marine Biomass for the Treatment of Wastewaters Containing U and Th: The Kinetics and Equilibrium of Biosorption
         by Antonio C. A. da Costa, Antonia C. da Silva, Ana C. M. Ferreira

         Vol. 4. n. 5, pp. 440-449


Abstract -  Sargassum filipendula was used for kinetic and equilibrium studies of the biosorption of Th and U. Tests were performed with 1 and 10 mg/L solutions, pH 1.0 and 4.0 at 25±1ºC. Biosorption was optimal at distinct pH values depending on the radionuclide. Kinetic data indicated a fast equilibrium and a good correlation between experimental data and a second-order kinetic model. Equilibrium batch tests also showed that results from Th biosorption were best represented by the Freundlich Equation. On the other hand, U biosorption was best represented by the Langmuir Equation. For combined solutions biosorption of Th was not affected by the presence of U.

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Keywords: Uranium, Thorium, Biosorption, Kinetics, Equilibrium, Sargassum Filipendula.



go to top   Long-Term Hydration of Dicalcium Silicates
         by Mariane Silva de Miranda, Flávio Aparecido Rodrigues

         Vol. 4. n. 5, pp. 450-454


Abstract -  This work describes the synthesis and hydration of β-Ca2SiO4 and β-Ca2SiO4 doped with zirconium and manganese. It was observed that the maximum level of insertion was 1% for zirconium and 5% for manganese. Hydration was followed up to 5 years using x-ray diffraction, differential thermal analysis and scanning probe microscopy. Thermal analysis shows that water is continuously bounded to cement and reaches a stationary situation after approximately 500 days. However even after this period, the process continues, involving production and consume of calcium hydroxide. It was also observed that the surface of silicate changes steadily. Surface roughness, measured by scanning probe microscopy, can be used to characterize these modifications.

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Keywords: Dicalcium Silicate, Cement, Hydration.



go to top   Thermodynamic Modeling of PES/CA Blend Membrane Preparation
         by H. Abdallah, S. S. Ali

         Vol. 4. n. 5, pp. 455-465

Abstract - Thermodynamic behavior of quaternary system with one low molecular weight component; N –Methylpyrrolidone (NMP) as a solvent, non-solvent; polyethylene glycol (PEG 400) and two high molecular weight polymers; polyethersulfone (PES) and cellulose acetate (CA) was investigated. An extended modified Flory-Huggins model was used. The predicted results from model of critical temperature for superiority properties of polymer blend solution were in range between UCST 323 K and LCST 350 K. However, the increasing the vaporization time of PES/CA blend membrane to 30 min has increased the heat of vaporization to 133659.6 J/mole which led to increase in cohesive energy density to 1311.82 J/cm3 and gained more solvent evaporation. The diffusion model was studied on the immersion precipitation process which was indicated that solvent and non-solvent volume fractions increased with time in the coagulation bath , while the polymer solution volume fraction decreased due to solvent and non-solvent removal from polymer solution and blend membrane formation. The predicted results from model of heat treatment process on blend membrane were indicated that increasing in membrane thickness and formation of dense layer in blend membrane.

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Keywords: Thermodynamic Behavior, Quaternary System, Immersion Precipitation, Heat Treatment.



go to top   Thermodynamic Analysis of Ethanol Dehydration to Ethylene through Equilibrium Constant Method Using Classic Thermodynamics and Quantum Chemistry
         by Alice M. de Lima, Adilson J. de Assis, Carla E. Hori, Miria H. E. Reis, Antonio E. H. Machado

         Vol. 4. n. 5, pp. 466-473

Abstract - In the last decades, ethylene production from ethanol was not largely investigated mainly because of the viability and low costs of natural gas and naphtha. Nowadays, ethylene production is usually done by cracking of hydrocarbons. However, the manufacture of ethylene from ethanol is getting more attention mostly due to environmental reasons. The objective of this paper is to compare the equilibrium conversions and compositions of reactions systems involved in ethylene production from ethanol through computational simulations. The obtained results can help to find better operational conditions and elucidate preferential reaction routes involved in ethanol dehydration.

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Keywords: Chemical Equilibrium, Ethanol Dehydration, Molecular Modeling.



go to top   Optimization of HPMC and Water Addition For a Gluten-Free Formula with Rice and Field Bean Based on Rheological Properties of Doughs
         by Le. Benatallah, M. N. Zidoune, C. Michon

         Vol. 4. n. 5, pp. 474-481


Abstract - Formulation and manufacture of gluten-free bread with rice and field bean were investigated. A 5-level Central Composite Design with two factors – hydroxypropylmethyl cellulose (HPMC) and water - was elaborated. Cereal dough samples composed of 2/1 (w/w) rice/field bean were made. Results were compared to a control of soft wheat. Rheological properties of dough (storage modulus, loss angle, stiffness, stress-hardening and relaxation index) were evaluated. A selection of two HPMC – water concentration domains were found using rheological values matching those of wheat flour dough. Within these two domains, rheological parameters and bread making tests were realized in order to confirm the validity. The level of HPMC-water which displays a specific volume closest to the control was [3.32-90.5]%. Loss angle, measured at 60°C, was inversely related to the fineness of breadcrumb as was the case for wheat dough. Crumb fineness increases with the specific volume of bread. No correlation was observed between crumb heterogeneity and stress-hardening character of gluten-free breads measured at different biaxial extension rates. Moreover a more marked stress-hardening character measured at 38°C and at low biaxial extension rate seems to lead to bread with small specific volume.

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Keywords: Formulation, Gluten-Free Doughs, Rice, Field Bean, Specific Volume, Rheological Properties, Alveolar Structure.



go to top   Effect of Temperature on Continuous Production of Sulfur and Formaldehyde Coated Urea
         by M. H. Ismayanda, A. Muslim
Vol. 4. n. 5, pp. 482-486


Abstract - An immersing and spray coating process has been developed for the continuous production of sulfur coated urea (SCU) and formaldehyde coated urea (FCU) in a fluidized bed. The coated urea was produced in a laboratory scale unit with the coating temperature of 30, 50 and 70oC. The SCU and FCU dissolution rates were studied and performed in a stirred tank. The effect of coating temperature was investigated, and a result showed that the dissolution of SCU and FCU in distilled water decreased with the increase in coating temperature. Referenced models and optimization method were adopted to obtain the SCU and FCU diffusion coefficients, and the experiment based results were in very good agreements with the model based results. As the result, the SCU diffusion coefficient was approximately 1.733E-05, 1.643E-05 and 1.402E-05, and the FCU diffusion coefficient was approximately 2.246E-05, 1.877E-05 and 1.531E-05 for the coating temperatures of 30, 50 and 700C respectively. In addition, the SCU dissolution rate was approximately 0.149, 0.144 and 0.129 g/min, and the FCU dissolution rate was approximately 0.167, 0.152 and 0.132 g/min for the coating temperatures of 30, 50 and 700C respectively. It was obvious that increasing the coat temperature resulted in increasing the diffusion and dissolution of urea, and sulfur was the better coating material than formaldehyde in terms of controlled release of urea.

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Keywords: Urea, Coating, Dissolution, Diffusion, Fluidized Bed, Stirred Tank.



Open Door Initiative (ODI) 3rd edition - Papers



go to top   Preface
         by Jordan Hristov

         Vol. 4. n. 5, pp. 487-488


go to top   An Exercise with the He’s Variation Iteration Method To a Fractional Bernoulli Equation Arising in Transient Conduction with Non-Linear Heat Flux at the Boundary
         by Jordan Hristov

         Vol. 4. n. 5, pp. 489-497

Abstract - Surface temperature evolution of a body subjected to a nonlinear heat flux involving counteracting convection heating and radiation cooling has been solved by the variations iteration method (VIM) of He. The surface temperature equations comes as a combination of the time-fractional (half-time) subdiffusion model of the heat conduction and the boundary condition relating the temperature field gradient at the surface through the Riemann-Liouville fractional integral. The result of this equation is a Bernoulli-type ordinary fractional equation with a non-linear term of 4th order. Two approaches in the identification of the general Lagrange multiplier and a consequent application of VIM have been applied. The common method replaces the fractional integral (in the Riemann-Liouville sense) by an integer order integral. The more exact method of Wu uses an initial Laplace transform of the fractional integral in the iteration formula to find correctly the Lagrange multiplier. Both approaches yield different Lagrange multipliers which results in different numerical results.The article discusses the origin of these differences in the light of correct application of VIM. The developed approximate solutions have been used in numerical simulation showing the effect of Biot number and the radiation-conduction number on the surface temperature evolution.

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Keywords: Variational Iteration Method, Bernoulli-Like Fractional Equation, Lagrange Multiplier, Surface Temperature Evolution. 



go to top   A Note on an Improved Variational Iteration Method for Nonlinear Equations Arising in Heat Transfer
         by Fazhan Geng
Vol. 4. n. 5, pp. 498-500

Abstract - An improved variational iteration method for solving nonlinear equations arising in heat transfer is conceived. The main advantage of the present method is that it can enlarge the convergence region of iterative approximate solutions. Also, the present method can be used to solve strong nonlinear problems. Comparison of the result obtained using this method with other existing methods reveals that the present method is more effective and convenient for these types of nonlinear problems.

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Keywords: Variational Iteration Method, Heat Transfer. 



go to top   Approximate Solution of Fractional Diffusion Equation – Revisited
         by S. Das
Vol. 4. n. 5, pp. 501-504

Abstract - The article presents the approximate analytical solution of a fractional diffusion equation with the help of powerful mathematical tool viz., variational iteration method. Fractional diffusion equation has special importance in engineering and science, and constitutes a good model for many systems in various fields. By using initial value, the explicit solution of the equation has been derived, which accelerate the rapid convergence of the series solution. The striking features of the article are successful presentation of sub-diffusion characteristics of the probability density function through numerical computation due to the presence of reaction term for various fractional Brownian motions and for different specified values of the considered parameters.

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Keywords: Fractional Derivative, Diffusion Equation, Initial Value, Sub-Diffusion, Reaction Term, Variational Iteration Method. 



go to top   Applications of the Variational Iteration Method to Fractional Diffusion Equations: Local versus Nonlocal Ones
         by Guo-Cheng Wu
Vol. 4. n. 5, pp. 505-510

Abstract - The diffusion equations with the local and the nonlocal fractional derivatives have been used to describe the flow through disorder media. Recently, the variational iteration method is successfully developed to find approximate solutions of the two kinds of fractional differential equations.
This study reveals the new development of the method and compares the applications in two types of fractional diffusions.

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Keywords: Fractional Diffusion Equation, Variational Iteration Method, Lagrange Multipliers, Caputo Derivative, Riemann-Liouville Derivative, Kolwankar-Gangal’s Derivative. 



go to top   Application of the Variational Iteration Method for Determining the Temperature in the Heterogeneous Casting-Mould System
         by Edyta Hetmaniok, Konrad Kaczmarek, Damian Słota, Roman Wituła, Adam Zielonka
Vol. 4. n. 5, pp. 511-515

Abstract - In this paper an application of the variational iteration method for determining the temperature in the heterogeneous casting-mould system is presented. Considered problem is modeled by means of the system of two heat conduction equations – for the casting and for the mould, on the contact surface of which the boundary condition of the fourth kind with non-zero thermal resistance is defined. An example illustrating the discussed application and confirming usefulness of this method in solving such kind of problems is also presented.

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Keywords: Heat Conduction, Casting-Mould System, Variational Iteration Method. 



go to top   Mathematical Modelling and Transient Analytical Solution of a Glucose Sensitive Composite Membrane for Closed-Loop Insulin Delivery Using He’s Variational Iteration Method
         by R. Angel Joy, L. Rajendran
Vol. 4. n. 5, pp. 516-523

Abstract - A mathematical modelling of an enzymatic reaction and diffusion of reactants and product inside glucose sensitive composite membrane is discussed. The model is based on time-and position-dependent diffusivity of species and involves the system of non-linear reaction diffusion equations. He’s variational iteration method is used to obtain approximate and analytical solutions of the system. A comparison of the analytical approximation and numerical simulation is also presented.

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Keywords: Enzymatic Reaction, Nonlinear Partial Differential Equations, He’s Variational Iteration Method, Boundary Value Problem, Glucose Sensitive Composite Membrane. 



go to top   Efficacy of Variational Iteration Method for Nonlinear Heat Transfer Equations – Classical and Multistage Approach
         by Montri Torvattanabun, Sanoe Koonprasert, Somjate Duangpithak
Vol. 4. n. 5, pp. 524-528

Abstract - This is paper, we are study of solving nonlinear convective-radiative cooling equation by using the classical variational iteration method (VIM) and modified version called the multistage variational iteration method (MVIM). This method is based on the use of Lagrange multipliers for identification of optimal values of parameters in a functional. Furthermore, a theorem for the convergence of the MVIM is presented and comparison of the results obtained by VIM, MVIM and homotopy-perturbation method (HPM) with exact solutions.

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Keywords: Heat Transfer, Nonlinear Equation, Variational Iteration Method, Convergence.


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