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Siavash Ashoori Behnam Shahsavani Ahmad Rezaei 《Journal of Dispersion Science and Technology》2014,35(9):1325-1338
An little known yet significant issue in petroleum production processes in petroleum reservoirs is asphaltene precipitation/deposition. Asphaltene has not only a fuzzy and vague nature but it also can cause detrimental problems like reservoir blockage and, as a result, low oil recovery. To tackle this issue, many researchers have attempted to monitor asphaltene behavior versus thermodynamic conditions. A thermodynamic micellization approach is implemented in this work to describe asphaltene precipitation behavior for two sample fluids from Iranian reservoirs. First, the basic structures of the addressed approach and different contributions to Gibbs free energy of micellization proposed by Victorov and Firoozabadi (VF) are demonstrated. Second, a detailed sensitivity analysis with respect to the model parameters is performed by utilizing a new calculation strategy. Finally, a comparison between the predicted precipitation curve and the experimental one is illustrated; moreover, comparing our results with those reported by Victorov proves the superiority of the new strategy over the conventional one. The significance of this study shows the effect of each micellization parameter on the asphaltene precipitation behavior curve and illustrates the ability of the micellization approach evolved by VF in monitoring the effect of pressure on asphaltene precipitation using the new calculation procedure. Outcomes from this study could couple with commercial reservoir simulation software to improve precision and integrity for designing robust and effective production units. 相似文献
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Electrochemical Determination of Dextromethorphan on Reduced Graphene Oxide Modified Screen‐Printed Electrode after Electromembrane Extraction
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Ali Reza Fakhari Mohammad Hossein Koruni Hamid Ahmar Abolfath Shahsavani Siyavash Kazemi Movahed 《Electroanalysis》2014,26(3):521-529
In this paper, electromembrane extraction coupled with differential pulse voltammetry (DPV) on a reduced graphene oxide modified screen‐printed carbon electrode (RGO‐SPCE) for the determination of dextromethorphan (DXM) in urine and plasma has been described. DXM migrated from 4 mL of a donor phase across a thin layer of 2‐nitrophenyl octyl ether (NPOE) immobilized in the pores of a porous hollow fiber, into a 20 µL acceptor phase (HCl) present inside the lumen of the fiber. Then, 15 µL of a 0.1 M NaOH solution was added to the acceptor phase and the mixture was analyzed using DPV. 相似文献
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We demonstrate the existence of ferrimagnetic and ferromagnetic phases in a spin phase diagram of coupled lateral quantum dot molecules in the quantum Hall regime. The spin phase diagram is determined from the Hartree-Fock configuration interaction method as a function of electron number N and magnetic field B. The quantum Hall ferrimagnetic phase corresponds to spatially imbalanced spin droplets resulting from strong interdot coupling of identical dots. The quantum Hall ferromagnetic phases correspond to ferromagnetic coupling of spin polarization at filling factors between nu=2 and nu=1. 相似文献
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Quantitative structure–property relationships of retention indices of some sulfur organic compounds using random forest technique as a variable selection and modeling method
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We present unrestricted Hartree-Fock method coupled with configuration interaction (CI) method (URHF-CI) suitable for the calculation of ground and excited states of large number of electrons localized by complex gate potentials in quasi-two-dimensional quantum dot molecules. The method employs real space finite difference method, incorporating strong magnetic field, for calculating single particle states. The Hartree-Fock method is employed for the calculation of direct and exchange interaction contributions to the ground state energy. The effects of correlations are included in energies and directly in the many-particle wave functions via CI method using a limited set of excitations above the Fermi level. The URHF-CI method and its performance are illustrated on the example of ten electrons confined in a two-dimensional quantum dot molecule. 相似文献
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Alireza Hasaninejad Abdolkarim Zare Ahmad Reza Moosavi Zare Abolfath Parhami Hashem Sharghi Ali Khalafi-Nezhad 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2769-2776
An efficient solvent-free procedure for the preparation of N-arylsulfonyl imines from sulfonamides and aryl aldehydes in the presence of a catalytic amount of magnesium oxide and tetrabutylammonium bromide (TBAB) under microwave irradiation is described. The advantages of this method are good to high yields, short reaction times, low cost, and matching with green chemistry protocols. 相似文献
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Mohammad Navid Soltani Rad Ali Khalafi-Nezhad Mohammad Ali Faghihi Abolfath Parhami 《Tetrahedron》2008,64(8):1778-1785
A convenient and efficient one-pot N-alkylation of nucleobases from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of purine or pyrimidine nucleobase, TsIm, K2CO3, and triethylamine in refluxing DMF regioselectively furnishes the corresponding N-alkyl nucleobases in good yields. This methodology is highly efficient for various structurally diverse primary alcohols. 相似文献
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Reza?YousefiEmail author Mehrnaz?Jamshidi Mohammad?Bagher?Shahsavani S.?Masoud?Nabavizadeh Mohsen?Golbon?Haghighi Mehdi?Rashidi Asghar?Taheri-Kafrani Ali?Niazi Fatemeh?Keshavarz Mohammad?Mehdi?Alavinamehr 《Journal of the Iranian Chemical Society》2016,13(4):617-630
Human serum albumin (HSA) primarily functions as a transport carrier for a vast variety of natural ligands and pharmaceutical drugs. In the present study, three structurally related cationic Pt(II) complexes ([Pt(ppy)(dppe)]CF3CO2: 1, Pt(bhq)(dppe)]CF3CO2: 2, and [Pt(bhq)(dppf)]CF3CO2: 3) were used to evaluate their interaction with HSA under different experimental setups, using UV–Vis absorption spectroscopy, fluorescence and circular dichroism techniques. The spectroscopic results suggest that upon binding to HSA, the Pt(II) complexes could effectively induce structural alteration of the protein. The complexes can bind to HSA with the binding affinities of the following order: 3 > 2 > 1. Also, thermodynamic parameters of binding between these complexes and HSA indicated the existence of entropy-driven spontaneous interaction which primarily dominated with the hydrophobic forces. Also, docking simulation study revealed the binding details of these complexes on HSA. Complex 3 with highest binding affinity for HSA indicates lowest denaturing effect on this protein. The low denaturation properties of 3 appear important in the terms of lower susceptibility of this platinum complex for possible development of deleterious side effects. 相似文献
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We employ molecular dynamic simulations to study the reduction process of graphene oxide (GO) in a chemically active environment enriched with hydrogen. We examine the concentration and pressure of hydrogen gas as a function of temperature in which abstraction of oxygen is possible with minimum damage to C-sp(2) bonds, hence preserving the integrity of the graphene sheet. Through these studies we find chemical pathways that demonstrate beneficiary mechanisms for the quality of graphene including formation of water as well as suppression of carbonyl pair holes in favor of hydroxyl and epoxide formation facilitated by hydrogen gas in the environment. 相似文献