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    Effect of asphaltene and resin on interfacial tension of acidic crude oil/ sulfate aqueous solution: Experimental study

    , Article Fluid Phase Equilibria ; Volume 414 , 2016 , Pages 149-155 ; 03783812 (ISSN) Lashkarbolooki, M ; Ayatollahi, S ; Sharif University of Technology
    Elsevier  2016
    Although the capability of using sulfate anion as a wettability modiffier is well established, no systematic investigation on the effect of sulfate ions and natural surfactants in the crude oil including asphaltene and resin on the interfacial tension (IFT) of acidic crude oil (ACO)/sulfate were performed. In this regards, the fluid/fluid interactions are tested through the IFT measurements for ACO, asphaltene and resin extracted from ACO in the presence of sulfate salts including Na2SO4, MgSO4 and CaSO4 while the concentration of each salt ranges between 0 and 45000 ppm. The obtained results demonstrate that the capability of asphaltene molecules is higher for IFT reduction compared with... 

    One step synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes using sodium hydrogen sulfate as catalyst

    , Article Monatshefte fur Chemie ; Volume 139, Issue 6 , 2008 , Pages 605-608 ; 00269247 (ISSN) Karimi Jaberi, Z ; Hashemi, M. M ; Sharif University of Technology
    A simple and environmentally benign procedure for the synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes is described through a one-pot condensation of 2-naphthol with aryl or alkyl aldehydes in the presence of sodium hydrogen sulfate as a catalyst under solvent-free conditions. © 2008 Springer-Verlag  

    A mild and chemoselective dithioacetalization of aldehydes in the presence of anhydrous copper (II) sulfate

    , Article Phosphorus, Sulfur and Silicon and the Related Elements ; Volume 181, Issue 6 , 2006 , Pages 1445-1450 ; 10426507 (ISSN) Matloubi Moghaddam, F ; Rezanejade Bardajee , G ; Arefi Oskui , A ; Sharif University of Technology
    Various aldehydes have been protected with different thiols as dithioacetals with excellent yields using anhydrous copper sulfate as a mild and chemoselective catalyst. The reaction is carried out in a solvent and/or under solvent-free conditions. The transthioacetalization of oxyacetals into dithioacetals was also achieved in an excellent yield. Copyright © Taylor & Francis Group, LLC  

    Application of Sulfur Degrading Bacteria in Bioremediation

    , M.Sc. Thesis Sharif University of Technology Ghaffari, Leila (Author) ; Kariminia, Hamid Reza (Supervisor)
    The main objective of this research was to evaluate the application of a new strain of Brevundimonas naejangsanensis which is newly identified sulfate-reducing bacteria (SRB), in bioremediation. A laboratory scale packed bed reactor (PBR) was fabricated and operated to study the new bacteria’s feasibility on SO_4^(2-) reduction. The reactor was packed with polyurethane foam cubes and operated under different feeding and operating conditions of HRT, COD/SO_4^(2-) ratio and salinity. A maximum SO_4^(2-) reduction of 73.6% was achieved in the PBR when operated at an HRT of 12 h with SO_4^(2-) concentration of 670 mg/L, COD/SO_4^(2-) ratio of 1 and salinity of 3%. The results show that this... 

    Reactive Crystallization in an Impinging Jets Reactor

    , M.Sc. Thesis Sharif University of Technology Raoufi, Farzan (Author) ; Molaei Dehkordi, Asghar (Supervisor)
    Reactive crystallization or precipitation is an important industrial process. Many chemicals and biochemicals such as catalysts and pigments are produced by precipitation. Because of the advantages of impinging jets in chemical engineering processes, the main aim of this research was to investigate the application of this method in precipitation and to study the effects of different operating and design parameters on the product’s quality and properties. Two chemical models of barium sulfate and copper oxalate were used as main products. Each of these chemicals was produced by a liquid-liquid reaction of two aqueous solutions, which were fed to an impinging-jets reactor. Effects of... 

    Rigorous modeling of gypsum solubility in Na-Ca-Mg-Fe-Al-H-Cl-H2O system at elevated temperatures

    , Article Neural Computing and Applications ; Volume 25, Issue 3 , September , 2014 , pp 955-965 ; ISSN: 09410643 Safari, H ; Gharagheizi, F ; Lemraski, A. S ; Jamialahmadi, M ; Mohammadi, A. H ; Ebrahimi, M ; Sharif University of Technology
    Precipitation and scaling of calcium sulfate have been known as major problems facing process industries and oilfield operations. Most scale prediction models are based on aqueous thermodynamics and solubility behavior of salts in aqueous electrolyte solutions. There is yet a huge interest in developing reliable, simple, and accurate solubility prediction models. In this study, a comprehensive model based on least-squares support vector machine (LS-SVM) is presented, which is mainly devoted to calcium sulfate dihydrate (or gypsum) solubility in aqueous solutions of mixed electrolytes covering wide temperature ranges. In this respect, an aggregate of 880 experimental data were gathered from... 

    Electrodeposition of Ni/WC nano composite in sulfate solution

    , Article Materials Chemistry and Physics ; Volume 129, Issue 3 , 2011 , Pages 746-750 ; 02540584 (ISSN) Mohajeri, S ; Dolati, A ; Rezagholibeiki, S ; Sharif University of Technology
    Metal matrix composite coatings have gained great attention due to their exclusive properties. They have shown the properties of a metallic host material modified by addition of a second phase. In electrodeposition of Ni/WC nano composite, nickel was deposited on the substrates by DC electrodeposition in Watt's based bath containing nickel sulfate, nickel chloride, boric acid and sodium dodecyl sulfate. WC content in the coating was determined by different parameters such as current density, powder content and surfactant amount. Mechanism of electrodeposition was analyzed by cyclic voltammetry and was confirmed by Guglielmi model. Surface morphology was studied by scanning electron... 

    Evaluation of the simultaneous effects of sulfate reducing bacteria, soil type and moisture content on corrosion behavior of buried carbon steel API 5L X65

    , Article International Journal of Electrochemical Science ; Volume 11, Issue 5 , 2016 , Pages 3887-3907 ; 14523981 (ISSN) Madani Sani, F ; Afshar, A ; Mohammadi, M ; Sharif University of Technology
    Electrochemical Science Group 
    For the first time, the simultaneous effects of sulfate reducing bacteria (SRB), soil type and moisture content on corrosion behavior of a pipeline steel were investigated. Corrosion weight loss measurements were performed in abiotic control and SRB-active conditions, at three different moisture contents, and in two types of soils. Results showed that the presence of SRB in the soils, although increased the corrosion rate and aggravated pitting corrosion at low moisture contents, had a protective effect at high moisture contents. The corrosion rates showed a maximum at the saturation moisture content (SMC) of the soils. Soil physicochemical analyses showed that the corrosion rate and soil... 

    Synthesis of Bis(indolyl)methanes in presence of anhydrous copper(II) sulfate

    , Article Asian Journal of Chemistry ; Volume 20, Issue 2 , 2008 , Pages 1063-1067 ; 09707077 (ISSN) Matloubi Moghaddam, F ; Bardajee, G. R ; Ismaili, H ; Sharif University of Technology
    This work reports the improved procedure for the preparation of bis(indolyl)methanes from the corresponding aldehydes and indole. Anhydrous copper(II) sulfate efficiently promotes the chemoselective synthesis of bis(indolyl)methanes via electrophilic substitution reactions of indole with aldehydes. The reaction was carried out in refluxing dichloromethane or microwave-assisted solvent-free conditions. The adducts were produced in good to excellent yields  

    Synthesis and properties of lead oxide carbonate

    , Article Inorganic Materials ; Volume 42, Issue 10 , 2006 , Pages 1099-1103 ; 00201685 (ISSN) Sajadi, S. A. A ; Alamolhoda, A. A ; Sharif University of Technology
    PbCO 3·PbO and PbCO 3·2PbO compounds were prepared by thermal methods. The structure of each compound was determined by using XRD technique, and their purity was confirmed by analytical methods (98%). Also the thermal characteristics of each compound were investigated by thermogravimetry. At 600°C both compounds decompose completely and produce lead(II) oxide. © 2006 Nauka/Interperiodica  

    Preparation of Titania based solid strong acid and study of its catalytic activity in esterification of Phthalic anhydride and Sebacic acid

    , Article Materials Letters ; Volume 60, Issue 6 , 2006 , Pages 715-719 ; 0167577X (ISSN) Khodadadi Moghaddam, M ; Gholami, M. R ; Sharif University of Technology
    Esterification of Phthalic anhydride with 2-Octanol and Sebacic acid with Ethanol has been studied in the presence of Sulfated Titania. This study showed that Sulfated Titania has strong catalytic effect on esterification reactions. The effect of some factors such as reaction temperature, molar ratio of acid to alcohol, amount of catalyst used, reaction time, calcination temperature, drying temperature and calcination atmosphere has been investigated. Equilibrium composition achieved in 80 min for Diethyl Sebacate and 20 min for Dioctyl Phthalate in various conditions. © 2005 Elsevier B.V. All rights reserved  

    Synthesis of barium sulfate nanoparticles using a spinning disk reactor: Effects of supersaturation, disk rotation speed, free ion ratio, and disk diameter

    , Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 16 , 2009 , Pages 7574-7580 ; 08885885 (ISSN) Dehkordi, A. M ; Vafaeimanesh, A ; Sharif University of Technology
    The aim of this research was to synthesize barium sulfate nanoparticles using a spinning disk reactor. Barium sulfate was produced by continuously pumping two aqueous solutions of BaCl2 and Na2SO 4, respectively, into the chamber of spinning disk reactor, where a liquid-liquid reaction took place to form BaSO4. The influences of various operating and design parameters such as the initial supersaturation, disk rotation speed, free ion ratio, and the disk diameter on the size of barium sulfate nanoparticles were carefully investigated. By varying the supersaturation and disk rotation speed, a broad range of particle size ranging from micrometer sizes down to nanoparticles smaller than 100 nm... 

    Investigation and Optimization of Ni-P-Zn Electroless Alloy Coatings

    , M.Sc. Thesis Sharif University of Technology Kordijazi, Amir (Author) ; karam, SaeedAllah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    An optimization condition for obtaining Ni-Zn-P electroless alloy coating has been developed. The sulphate bath with sodium hypophosphate as a reducer and sodium citrate and ammonium chloride as complexing agents were used. The effect of variation in the pH level , temperature , time of deposition and reactants concentration on stability of bath, coating composition, microstructure, microhardness and corrosion resistance of coatings was investigated. The composition of coatings was obtained by using the EDAX analysis. To investigate coating morphology, SEM images were taken and to study the corrosion behavior of coatings potentidynamic polarization, Electrochemical Impedance Spectroscopy... 

    Influence of process variables on biooxidation of ferrous sulfate by an indigenous Acidithiobacillus ferrooxidans. Part I: Flask experiments

    , Article Fuel ; Volume 85, Issue 17-18 , 2006 , Pages 2555-2560 ; 00162361 (ISSN) Mousavi, S. M ; Yaghmaei, S ; Salimi, F ; Jafari, A ; Sharif University of Technology
    Biological oxidation of ferrous sulfate by Acidithiobacillus ferrooxidans has proved to be a significant step in the bioleaching of sulfide minerals and the treatment of acid mine drainage. The same bioreaction also has beneficial applications in the desulphurization of coal and removal of hydrogen sulfide from gaseous effluents. In this research, the effects of some process variables such as pH, temperature, elemental sulfur, amount of initial ferrous and magnesium ions on oxidation of ferrous sulfate by a native A. ferrooxidans, which was isolated from a chalcopyrite concentrate, were investigated. All experiments carried out in shake flasks at 33 °C that was obtained as optimum... 

    Extraction of fluoxetine from aquatic and urine samples using sodium dodecyl sulfate-coated iron oxide magnetic nanoparticles followed by spectrofluorimetric determination

    , Article Analytica Chimica Acta ; Volume 692, Issue 1-2 , 2011 , Pages 80-84 ; 00032670 (ISSN) Bagheri, H ; Zandi, O ; Aghakhani, A ; Sharif University of Technology
    A new method based on the combination of magnetic solid phase extraction (MSPE) and spectrofluorimetric determination was developed for isolation and preconcentration of fluoxetine form aquatic and biological samples using sodium dodecyl sulfate (SDS) coated Fe3O4 nanoparticles (NPs) as a sorbent. The unique properties of Fe3O4 NPs including high surface area and strong magnetism were utilized effectively in the MSPE process. Effect of different parameters influencing the extraction efficiency of fluoxetine including the amount of Fe3O4 and SDS, pH value, sample volume, extraction time, desorption solvent and time were optimized. Under optimized condition, the method was successfully applied... 

    Experimental Study of Improved Oil Recovery by Low-Salinity Waterflooding in Asphaltenic Reservoirs

    , M.Sc. Thesis Sharif University of Technology Rashid, Saeed (Author) ; Ayatollahi, Shahaboddin (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
    There is increasing evidence that injecting modified brines has a significant impact on the amount of oil recovered, but the exact mechanism by which this occurs is an unsettled issue, and is supposed to be a cause of the complex interactions occurring between the phases insitu. In this thesis, surface chemistry of smart water has been investigated. Fluid/solid and fluid/fluid interactions for Bangestan crude oil in tfhe presence of designed solutions and a set of dilutions of Persian Gulf seawater have been studied and compared. Fluid/solid interactions were investigated through wettability studies. Impact of salinity and ionic composition on this interaction was measured through contact... 

    Solphate Leaching of Titanium Minerals from Shore Reservoir of in the North of Iran and Refining of Iron and other Impurities

    , M.Sc. Thesis Sharif University of Technology Behvar, Alireza (Author) ; Yoozbashizadeh, Hossein (Supervisor)
    The most important raw material for production of titanium dioxide is titanium that used in Aerospace, Plastic, Pigment and Pharmacy industries. Due to the presence of titanium minerals in Iran, reduce imports of titanium dioxide is one of the goals of the Ministry of Industries and Mines to achieve self-sufficiency in the production of TiO2.One of the very rich sources of titanium is alluvial sands in northern of Iran. In this study the TiO2 high grade pigment production from these sources has been investigated. Titanium-bearing sands with 9.5% TiO2 are used to produce high grade TiO2 pigment. After magnetic separation stage and reach a purity of 16.2% TiO2, upgrading slag step is not... 

    Some Studies on Conjugation of Nanoparticles Fe3O4 (Fe2O3) to PEG for Drug Delivery Systems

    , M.Sc. Thesis Sharif University of Technology Mohseni Ahooyi, Taha (Author) ; Vossoughi, Manouchehr (Supervisor) ; Yaghmaei, Soheila (Supervisor)
    The main strategy for treating solid cancers is based on the very early diagnosis of a malignant tumor, and in general the smaller the tumor, the greater the likelihood of successful treatment. Magnetic Resonance Imaging (MRI), based on the nuclear magnetic resonance phenomenon, provides the possibility of detecting early malignant tumors with the assistance of appropriate contrast agents. Hence, researchers continue to develop novel magnetic materials to achieve this aim. Superparamagnetic nanoparticles have become the focus of these studies because their superparamagnetic, biocompatible and hydrophilic properties would be revealed after modifying the particle surface by suitable... 

    Characterization of Protein Content in Soluble Microbial Products Involved in Fouling of Membrane Bioreactor

    , M.Sc. Thesis Sharif University of Technology Tanhaee, Zahra (Author) ; Torkian, Ayoub (Supervisor) ; Mousavi, Reza (Supervisor)
    Membrane bioreactors are increasingly being used for treatment of domestic and industrial effluents. A major operational drawback of this system is membrane fouling attributed to soluble microbial products (SMPs). In this study sampling were taken from microbial products on the surface and within the membrane pores and mixed liquir for mass characterization of protein content. Water-washing was used for surface and reversible portion of pore samples. Chemical wash with urea was used for further cleansing of SMPs within the pores. All samples were concentrate by precipitation with ammonium sulfate salt prior to analysis. Total protein content of samples was measured by lowry method. SDS-PAGE... 

    Simultaneous versus sequential adsorption of β-casein/SDS mixtures. Comparison of water/air and water/hexane interfaces

    , Article ACS Symposium Series ; Volume 1120 , 2012 , Pages 153-178 ; 00976156 (ISSN) ; 9780841227965 (ISBN) Dan, A ; Gochev, G ; Kotsmar, Cs ; Ferri, J. K ; Javadi, A ; Karbaschi, M ; Krägel, J ; Wüstneck, R ; Miller, R ; Sharif University of Technology
    This chapter is dedicated to the surface properties of mixed protein/surfactant adsorption layers, formed by two different experimental approaches, i.e. by sequential and simultaneous adsorption, respectively. A special modification of a drop profile analysis tensiometer, consisting of a coaxial double capillary, provides a unique protocol for studies of mixed surface layers formed by sequential adsorption of the individual components in addition to the traditional simultaneous adsorption from their mixed solution. A CFD simulation allowed to optimize the drop exchange process performed with the special double capillary arrangement. The experiments show that properties of sequentially formed...