Investigating the best mixture extraction systems in the separation of rare earth elements from nitric acid solution using Cyanex272, D2EHPA, and 8-Hydroxyquinoline

Seyed Mohammad Seyed Alizadeh Ganji,Seied Ziaeddin Shafaei,Nasser Goudarzi,Asghar Azizi 한국자원공학회 2016 Geosystem engineering Vol.19 No.1

This study is aimed at determining the optimum mixing ratio and solvent group to extract REEs from nitric leach solution, and the efficiency was tested using three different kinds of extractants, which were prepared to mix three different solvents of Cyanex272, D2EHPA, and HQ. In order to select the best mixture system, different volumes (ml) of solvent extractions were used under optimum conditions (.05 M concentration and pH of 2). The result indicated that the mixture system of Cyanex272 (8 ml) and D2EHPA (2 ml) had the highest separation factor and enrichment ratio in the separation of rare earth element, especially dysprosium. The degree of performance of mixture systems in separation of the rare earth elements indicated that the best extraction systems were in the order of Cyanex272 (8 ml) and D2EHPA (2 ml) > HQ (2 ml) and D2EHPA (8 ml) > Cyanex272 (8 ml) and HQ (2 ml).

Polypyrrole-polyaniline/Fe3O4 magnetic nanocomposite for the removal of Pb(II) from aqueous solution

Seyed Abolfazl Seyed Sadjadi,Amirhossein Afshar,Afsaneh Mollahosseini,Mohammadreza Eskandarian 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2

Lead ion which is engaged in aqueous solution has been successfully removed. A novel technique was utilized for the separation and absorption of Pb(II) ions from aqueous solution. Magnetic Fe3O4 coated with newly investigated polypyrrole-polyaniline nanocomposite was used for the removal of extremely noxious Pb(II). Characteristic of the prepared magnetic nanocomposite was done using X-ray diffraction pattern, Field emission scanning electron microscopy (FE-SEM), Fourier transform-infra red spectroscopy (FT-IR) and energy dispersive x-ray spectroscopy (EDX). Up to 100% adsorption was found with 20mg/L Pb(II) aqueous solution in the range of pH=8-10. Adsorption results illustrated that Pb(II) removal efficiency by the nanocomposite increased with an enhance in pH. Adsorption kinetics was best expressed by the pseudo-second-order rate form. Isotherm data fitted well to the Freundlich isotherm model. Upon using HCl and HNO3, 75% PPy-PAn/Fe3O4 nanocomposite, desorption experiment showed that regenerated adsorbent can be reused successfully for two successive adsorption-desorption cycles without appreciable loss of its original capacity.

Optimization of Extended UNIQUAC Parameter for Activity Coefficients of Ions of an Electrolyte System using Genetic Algorithms

Hashemi, Seyed Hossein,Dehghani, Seyed Ali Mousavi,Khodadadi, Abdolhamid,Dinmohammad, Mahmood,Hosseini, Seyed Mohsen,Hashemi, Seyed Abdolrasoul The Korean Institute of Chemical Engineers 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.5

In the present research, in order to predict activity coefficient of inorganic ions in electrolyte solution of a petroleum system, we studied 13 components in the electrolyte solution, including $H_2O$, $CO_2$ (aq), $H^+$, $Na^+$, $Ba^{2+}$, $Ca^{2+}$, $Sr^{2+}$, $Mg^{2+}$, $SO_4$, $CO_3$, $OH^-$, $Cl^-$, and $HCO_3$. To predict the activity coefficient of the components of the petroleum system (a solid/liquid equilibrium system), activity coefficient model of Extended UNIQUAC was studied, along with its adjustable parameters optimized based on a genetic algorithm. The total calculated error associated with optimizing the adjustable parameters of Extended UNIQUAC model considering the 13 components under study at three temperature levels (298.15, 323.15, and 373.15 K) using the genetic algorithm is found to be 0.07.

High accurate three-dimensional neutron noise simulator based on GFEM with unstructured hexahedral elements

Seyed Abolfazl Hosseini 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.6

The purpose of the present study is to develop the 3D static and noise simulator based on Galerkin FiniteElement Method (GFEM) using the unstructured hexahedral elements. The 3D, 2G neutron diffusion andnoise equations are discretized using the unstructured hexahedral by considering the linear approximationof the shape function in each element. The validation of the static calculation is performed viacomparison between calculated results and reported data for the VVER-1000 benchmark problem. Asensitivity analysis of the calculation to the element type (unstructured hexahedral or tetrahedron elements)is done. Finally, the neutron noise calculation is performed for the neutron noise source of typeof variable strength using the Green function technique. It is shown that the error reduction in the static calculation is considerable when the unstructuredtetrahedron elements are replaced with the hexahedral ones. Since the neutron flux distribution andneutron multiplication factor are appeared in the neutron noise equation, the more accurate calculationof these parameters leads to obtaining the neutron noise distribution with high accuracy. The investigationof the changes of the neutron noise distribution in axial direction of the reactor core shows thatthe 3D neutron noise analysis is required instead of 2D.

Control of the pressurized water nuclear reactors power using optimized proportional – integral – derivative controller with particle swarm optimization algorithm

Seyed Mohammad Hossein Mousakazemi,Navid Ayoobian,GHOLAM REZA ANSARIFAR 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.6

Various controllers such as proportionaleintegralederivative (PID) controllers have been designed andoptimized for load-following issues in nuclear reactors. To achieve high performance, gain tuning is ofgreat importance in PID controllers. In this work, gains of a PID controller are optimized for power-levelcontrol of a typical pressurized water reactor using particle swarm optimization (PSO) algorithm. Thepoint kinetic is used as a reactor power model. In PSO, the objective (cost) function defined by decisionvariables including overshoot, settling time, and stabilization time (stability condition) must be minimized(optimized). Stability condition is guaranteed by Lyapunov synthesis. The simulation resultsdemonstrated good stability and high performance of the closed-loop PSOePID controller to responsepower demand

The effective stiffness of an embedded graphene in a polymeric matrix

Seyed Mostafa Rahimian-Koloor,Hadi Moshrefzadeh-Sani,Seyed Majid Hashemianzadeh,Mahmood Mehrdad Shokrieh 한국물리학회 2018 Current Applied Physics Vol.18 No.5

Modeling the real sizes of an embedded graphene and the surrounding polymer of a representative volume element in a molecular dynamics simulation is a tedious task. The less computational limitations made the continuum-based method a good candidate for modeling of nanocomposites. However, having a good knowledge of mechanical properties of the embedded graphene in a polymeric matrix is a challenge for employing a continuum-based method. Since the applied stress on the graphene/epoxy nanocomposites has not been directly transferred to the embedded graphene, it brings the following question to mind. Is the stiffness of the embedded graphene different from that of the isolated one? To answer to this question, a model was developed by combining the molecular dynamic simulation and the finite element method to calculate the stiffness of an embedded graphene in a polymeric matrix. The results show that the longitudinal stiffness of the embedded graphene is different from that of the isolated graphene and is a function of its length. The use of this relationship in the micromechanical method leads to consider the nanosize effect in macroscale. The results were compared with some available experimental data to validate the model.

Development of Galerkin Finite Element Method Three-dimensional Computational Code for the Multigroup Neutron Diffusion Equation with Unstructured Tetrahedron Elements

Seyed Abolfazl Hosseini 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.1

In the present paper, development of the three-dimensional (3D) computational code basedon Galerkin finite element method (GFEM) for solving the multigroup forward/adjointdiffusion equation in both rectangular and hexagonal geometries is reported. Linearapproximation of shape functions in the GFEM with unstructured tetrahedron elements isused in the calculation. Both criticality and fixed source calculations may be performedusing the developed GFEM-3D computational code. An acceptable level of accuracy at a lowcomputational cost is the main advantage of applying the unstructured tetrahedron elements. The unstructured tetrahedron elements generated with Gambit software are usedin the GFEM-3D computational code through a developed interface. The forward/adjointmultiplication factor, forward/adjoint flux distribution, and power distribution in thereactor core are calculated using the power iteration method. Criticality calculations arebenchmarked against the valid solution of the neutron diffusion equation for InternationalAtomic Energy Agency (IAEA)-3D and Water-Water Energetic Reactor (VVER)-1000 reactorcores. In addition, validation of the calculations against the P1 approximation of thetransport theory is investigated in relation to the liquid metal fast breeder reactorbenchmark problem. The neutron fixed source calculations are benchmarked through acomparison with the results obtained from similar computational codes. Finally, ananalysis of the sensitivity of calculations to the number of elements is performed.

Sensitivity Analysis of the Galerkin Finite Element Method Neutron Diffusion Solver to the Shape of the Elements

Seyed Abolfazl Hosseini 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.1

The purpose of the present study is the presentation of the appropriate element and shapefunction in the solution of the neutron diffusion equation in two-dimensional (2D) geometries. To this end, the multigroup neutron diffusion equation is solved using theGalerkin finite element method in both rectangular and hexagonal reactor cores. Thespatial discretization of the equation is performed using unstructured triangular andquadrilateral finite elements. Calculations are performed using both linear and quadraticapproximations of shape function in the Galerkin finite element method, based on whichresults are compared. Using the power iteration method, the neutron flux distributionswith the corresponding eigenvalue are obtained. The results are then validated against thevalid results for IAEA-2D and BIBLIS-2D benchmark problems. To investigate the dependencyof the results to the type and number of the elements, and shape function order,a sensitivity analysis of the calculations to the mentioned parameters is performed. It isshown that the triangular elements and second order of the shape function in eachelement give the best results in comparison to the other states.

Damage identification of a 2D frame structure using two-stage approach

Seyed Rohollah Hoseini Vaez,Narges Fallah 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

In this article, a two-stage damage identification approach is employed to detect the site and extent of multiple damage cases in a 2D frame structure. In the first stage, Damage locating vector (DLV) method based on a new indicator called EDS (Exponential decreased stress) is applied to localize the damaged elements. Next, the damage extents of suspected elements are quantified using two metaheuristic algorithms, Water evaporation optimization (WEO) and accelerated WEO. Numerical example consists of a 2D frame structure with two types of meshing elements, 35 and 105 frame elements. For every state, two multiple damage cases are tested in noisy condition. To compare performance of the two-stage method with one-stage optimization method, the studied cases are also run using these two metaheuristic algorithms. The results indicate that the two-stage approach is more effective than one-stage because the number of intact element detected as damaged one and computational errors for actual damaged elements in one-stage method are more while the two-stage approach spends a much shorter time.

Analysis of an electrically actuated fractional model of viscoelastic microbeams

Seyed Masoud Sotoodeh Bahraini,Mohammad Eghtesad,Mehrdad Farid,Esmaeal Ghavanloo 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.5

The MEMS structures usually are made from silicon; consideration of the viscoelastic effect inmicrobeams duo to the phenomena of silicon creep is necessary. Application of the fractional model of microbeams made from viscoelastic materials is studied in this paper. Quasi-static and dynamical responses of an electrically actuated viscoelastic microbeam are investigated. For this purpose, a nonlinear finite element formulation of viscoelastic beams in combination with the fractional derivative constitutive equations is elucidated. The four-parameter fractional derivative model is used to describe the constitutive equations. The electric force acting on the microbeam is introduced and numerical methods for solving the nonlinear algebraic equation of quasi-static response and nonlinear equation of motion of dynamical response are described. The deflected configurations of a microbeam for different purely DC voltages and the tip displacement of the microbeam under a combined DC and AC voltages are presented. The validity of the present analysis is confirmed by comparing the results with those of the corresponding cases available in the literature.