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Convenient synthesis of chlorohydrins from epoxides using zinc oxide: Application to 5,6-epoxysitosterol
, Article Heteroatom Chemistry ; Volume 20, Issue 3 , 2009 , Pages 157-163 ; 10427163 (ISSN) ; Saeidian, H ; Mirjafary, Z ; Jebeli Javan, M ; Moridi Farimani, M ; Seirafi, M ; Sharif University of Technology
2009
Abstract
Efficient synthesis of protected and unprotected chlorohydrins has been achieved by ring opening of epoxides with acetyl/benzoyl chloride and TMSCl using a catalytic amount of ZnO as a reusable catalyst. The applicability of ZnO is further extended by performing the cleavage of the natural product 5,6-epoxysitosterol with acetyl chloride. © 2009 Wiley Periodicals, Inc
Study of the dependence of the specific output power of a copper chloride laser on the radial temperature profile of a gas plasma
, Article Quantum Electronics ; Volume 37, Issue 4 , 2007 , Pages 325-330 ; 10637818 (ISSN) ; Soltanmoradi, F ; Mohammadpour, R ; Tavakoli, M ; Zand, M ; Sharif University of Technology
2007
Abstract
The design of a copper chloride laser is described, and the laser is optimised by studying the dependence of its output power on the buffer gas type. The voltage and current of the laser discharge at the optimum buffer gas pressure are measured. The influence of the diaphragm diameter on the specific output power is studied after optimisation of switch parameters. When an diaphragm producing the optimal temperature gradient in the laser gas-discharge tube, the record specific output power of 123 W L-1 is obtained without any admixtures. ©2007 Kvantovaya Elektronika and Turpion Ltd
Determination of environmental water requirements of Lake Urmia, Iran: An ecological approach
, Article International Journal of Environmental Studies ; Volume 64, Issue 2 , 2007 , Pages 161-169 ; 00207233 (ISSN) ; Nazaridoust, A ; Sharif University of Technology
2007
Abstract
Lake Urmia is a thalassohaline ecosystem. It is an extremely simple ecological pyramid. This makes it a very sensitive ecosystem. This ecosystem has been facing various threats regarding the amount of water released from the associated basin. To calculate the lake water requirement with an ecological approach, we identified three variables: ecology, water quality, and water quantity indices as environmental indicators. The ecological index represented by Artemia urmiana is considered as an independent variable; while, the water quality index represented by concentration of NaCl, and the water quantity index represented by water elevation are regarded as dependent variables. The salinity...
A novel synthesis of some 2-imino-4-thiazolidinone derivatives
, Article Journal of Heterocyclic Chemistry ; Volume 44, Issue 1 , 2007 , Pages 35-38 ; 0022152X (ISSN) ; Hojabri, L ; Sharif University of Technology
HeteroCorporation
2007
Abstract
(Chemical Equation Presented) An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α-Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate
ZrOCl2·8H2O on montmorillonite K10 accelerated conjugate addition of amines to α,β-unsaturated alkenes under solvent-free conditions
, Article Tetrahedron ; Volume 62, Issue 4 , 2006 , Pages 672-677 ; 00404020 (ISSN) ; Eftekhari-Sis, B ; Abdollahifar, A ; Khalili, B ; Sharif University of Technology
2006
Abstract
At room temperature, ZrOCl2·8H2O on montmorillonite K10 efficiently catalyzes conjugate addition of amines to a variety of conjugated alkenes such as α,β-unsaturated carbonyl compounds, carboxylic esters, nitriles and amides under solvent-free conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency. © 2005 Elsevier Ltd. All rights reserved
Proficiency of tellurium extraction in pulsed disc and doughnut columns
, Article Separation Science and Technology (Philadelphia) ; Volume 56, Issue 18 , 2021 , Pages 3092-3105 ; 01496395 (ISSN) ; Torkaman, R ; Torab Mostaedi, M ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
In this research, the separation of tellurium from selenium was studied from chloride solution by TBP extractant. In the batch experiments, the experimental findings indicated that the feed acidity, TBP concentration, and contact time were optimized to achieve the high separation factor. In continuous mode of pulsed disc and doughnut column, the impacts of operating parameters have been discussed on the distribution coefficients of selenium and tellurium, and mass transfer enhancement. A new model for predicting Koca was proposed in terms of holdup values, Sherwood, Reynolds, and Schmidt numbers, which has an acceptable agreement with the mass transfer data. © 2020 Taylor & Francis Group,...
CuCl-Ne laser construction and its optimization on the specific output power
, Article Lasers and Applications, Warsaw, 28 August 2005 through 2 September 2005 ; Volume 5958 , 2005 , Pages 1-7 ; 0277786X (ISSN) ; Mohammadpour, R ; Tavakoli, M ; Soltanmoradi, F ; Zand, M ; Sharif University of Technology
2005
Abstract
In this work, after construction of a copper chloride laser, the effect of using different buffer gases on the output power has been examined. The voltage, current, laser pulses and the far field pattern of laser intensity were measured at the optimum buffer gas pressure. At these favorable conditions, the effect of using diaphragms in different diameters on the specific output power has been studied. By finding the desirable diaphragm size which creates the best temperature gradient in the laser tube the specific output record power of 123 (Watt/Lit) was obtained
Numerical Analysis of Behavior of Concrete-Filled PVC Tubular Column
, M.Sc. Thesis Sharif University of Technology ; Khalou, Alireza (Supervisor)
Abstract
Concrete Filled Polyvinyl Chloride (PVC) Tube (CFCT) technique has attracted significant research attention in recent years. PVC offers a number of advantages such as low costs and excellent properties like 1- high electrical insulation; 2- high resistance for abrasion; 3- low diffusion for humidity; 4- remarkable resistance to water, bases, acids, alcohols, oils; 5- large elongation at break; 6- low creep deformation; 7- workability including (cutting); 8- consistency; and 9- excellent corrosion resistant, durability and mechanical stability. The PVC tube acts as a longitudinal and transverse reinforcement and serves as a formwork which simplifies construction and reduces erection time. The...
Investigation of Water Salinity Effect on Asphaltene Precipitation Using PC-SAFT EOS
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
In this study, for investigation of water salinity effect on asphaltene modeling, PC-SAFT equation of state has been used. All steps of modeling have been done by C sharp programming language software. Nghiem model has been used for modeling of asphalting pure solid. In this model, the heaviest component is split into two precipitating and nonprecipitation parts that their physical properties are the same in each part. Furthermore, to determine the exact mechanism of asphaltene precipitation, an oil model (Asphaltene+heptan+tuloene) in the presence of different water brine such as synthetic brine (with MgCl2, CaCl2, and Na2SO4 salts), seawater) ten and two times diluted), and formation water...
On the formation of SWCNTs and MWCNTs by arc-discharge in aqueous solutions: The role of iron charge and counter ions
, Article Fullerenes Nanotubes and Carbon Nanostructures ; Volume 19, Issue 4 , 2011 , Pages 317-328 ; 1536383X (ISSN) ; Shervin, S. H ; Simchi, A ; Sharif University of Technology
Abstract
Single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) were synthesized in aqueous solutions containing FeCl2, FeCl3, FeSO4 and Fe2(SO4) 3. The effects of iron charge and the counter ions on the formation of carbon nanotubes (CNTs) were investigated. Thermogravimetric (TG) analysis indicated that carbon multilayer structures including CNTs and multishell graphite particles were formed in deionized (DI) water without the iron precursor. SWCNTs were also synthesized in the presence of the iron ions. It was also found that the mole ratio of [Fe2+]/[Fe3+] in the solution has a significant influence on the purity of CNTs and the process yield. The highest yield was...
Measurement and correlation of surface tension for single aqueous electrolyte solutions
, Article International Journal of Thermophysics ; Volume 31, Issue 4-5 , May , 2010 , Pages 852-859 ; 0195928X (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2010
Abstract
In this study, the values of the surface tension for a number of single aqueous electrolyte solutions were measured at various temperatures and electrolyte concentrations using the well-known and computer-aided pendant-drop method. In order to conduct the experimental measurements, a high-pressure IFT-700 apparatus, equipped with a view cell and a data acquisition system, was used. The systems studied in this study were aqueous solutions of KCl, NaCl, CaCl 2, and Na 2SO 4. The pooled standard deviation and the confidence limit of the surface-tension data for a 95 % confidence level were determined to be 0.17mN · m -1 and σ̄ ± 0.19, respectively. It should be noted that while the surface...
Effect of different bases and neutralization steps on porosity and properties of collagen-based hydrogels
, Article Polymer International ; Volume 59, Issue 1 , 2010 , Pages 36-42 ; 09598103 (ISSN) ; Kurdtabar, M ; Sharif University of Technology
Abstract
The aim of the work reported was to investigate the effect of bases and neutralization steps on hydrogel microstructures. A series of porous hydrogels with various pore sizes were prepared by neutralizing a conventional hydrogel after gel formation. Scanning electron microscopy was used to characterize the microstructure of the porous hydrogels. The morphology of the samples showed the pores were induced into the hydrogels by water evaporation and gas release resulting from the neutralization process. Experimental results indicated that the hydrogels had an absorbency of 200-220 and 48-50 g g-1 for distilled water and sodium chloride solutions, respectively. A simple method was used to...
Calcium chloride adsorption at liquid-liquid interfaces: A molecular dynamics simulation study
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 527 , 2017 , Pages 70-80 ; 09277757 (ISSN) ; Bahramian, A ; Chen, P ; Pourafshary, P ; Goddard, W.A., III ; Ejtehadi, M. R ; Sharif University of Technology
Abstract
We carried out molecular dynamics simulations (MD) to investigate the adsorption of calcium chloride (CaCl2) at n-hexane-water interfaces. We also measured the interfacial tensions (IFT) of the selected systems making use of the pendant-drop method. The histograms of hexane, water, and the ions indicate an electrical double layer (EDL) near the interface. The trend of the EDL indicates that chloride anions intend to adsorb to the interface more intrinsically than calcium cations. The measured interfacial width of the n-hexane-water interfaces decreases with the salt concentration. The average densities of the interfacial and bulk aqueous solutions demonstrate density heterogeneity in the...
Optimization of l-asparaginase immobilization onto calcium alginate beads
, Article Chemical Engineering Communications ; Volume 204, Issue 2 , 2017 , Pages 216-220 ; 00986445 (ISSN) ; Alemzadeh, I ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that...
Optimum rice husk ash content and bacterial concentration in self-compacting concrete
, Article Construction and Building Materials ; Volume 222 , 2019 , Pages 796-813 ; 09500618 (ISSN) ; Shoaei, P ; Bahrami, N ; Vaezi, M ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This study is aimed at optimizing the rice husk ash (RHA) content and bacterial concentration in self-compacting concrete (SCC). For this purpose, cement was partially replaced with RHA at 0%, 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. In addition, micro-silica (MS) was added to all mixes at a dosage of 10% by weight of cementitious materials. The mix with the optimum RHA content was supplied with bacterial cells with concentrations of 103, 105, and 107 cells/ml to reduce the formation of micro-cracks. The RHA concretes showed reduced workability with increasing RHA content. Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) analyses were performed on...
Plasma electrolytic oxidation and corrosion protection of friction stir welded AZ31B magnesium alloy-titanium joints
, Article Surface and Coatings Technology ; Volume 393 , 2020 ; Rogov, A ; Skeldon, P ; Zhou, X ; Yerokhin, A ; Aliabadi, A ; Ghorbani, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Joining of dissimilar light metals by friction stir welding (FSW) is of interest to reduce weight and fuel consumption in the transport sector. Such coupled metals may need protective surface treatments, e.g. against wear or corrosion, for some applications. In this work, the formation of plasma electrolytic oxidation (PEO) coatings in a silicate-based electrolyte for corrosion protection of FSW AZ31B magnesium alloy-titanium joints has been studied. The joints, if unprotected, may be susceptible to severe galvanic corrosion in chloride-containing environments. The coatings were characterized by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Mg2SiO4 and...
Measurement modulus of elasticity related to the atomic density of planes in unit cell of crystal lattices
, Article Materials ; Volume 13, Issue 19 , 2020 , Pages 1-17 ; Palevicius, A ; Dashti, A ; Nasiri, S ; Monshi, A ; Vilkauskas, A ; Janusas, G ; Sharif University of Technology
MDPI AG
2020
Abstract
Young’s modulus (E) is one of the most important parameters in the mechanical properties of solid materials. Young’s modulus is proportional to the stress and strain values. There are several experimental and theoretical methods for gaining Young’s modulus values, such as stress–strain curves in compression and tensile tests, electromagnetic-acoustic resonance, ultrasonic pulse echo and density functional theory (DFT) in different basis sets. Apparently, preparing specimens for measuring Young’s modulus through the experimental methods is not convenient and it is time-consuming. In addition, for calculating Young’s modulus values by software, presumptions of data and structures are needed....
Investigation of rock salt layer creep and its effects on casing collapse
, Article International Journal of Mining Science and Technology ; Volume 30, Issue 3 , 2020 , Pages 357-365 ; Pak, A ; Shad, S ; Mehrgini, B ; Razifar, M ; Sharif University of Technology
China University of Mining and Technology
2020
Abstract
Casing collapse is one of the costly incidents in the oil industry. In the oil fields of southwest Iran, most casing collapses have occurred in Gachsaran formation, and the halite rock salt layer in this formation may be the main cause for these incidents because of its peculiar creep behavior. In this research, triaxial creep experiments have been conducted on Gachsaran salt samples under various temperatures and differential stresses. The main purpose was to determine the creep characteristics of Gachsaran rock salt, and to examine the role of creep in several casing collapses that occurred in this formation. Results indicated that the halite rock salt of Gachsaran formation basically...
Evaluation of compressive and split tensile strength of slag based aluminosilicate geopolymer reinforced by waste polymeric materials using Taguchi method
, Article Materials Research Express ; Volume 8, Issue 2 , February , 2021 ; 20531591 (ISSN) ; Tayebi, M ; Shafiee, A ; Aghaie, A ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
In this work, slag based aluminosilicate geopolymer was reinforced with polymeric fibers including, polyester (PES) (waste tire cap plies), polymeric particles including polyethylene terephthalate (PET) (waste water bottle), styrene-butadiene rubber (SBR) (waste tire), and polyvinyl chloride (PVC) (waste water hose). The tensile and compressive strength of the material was evaluated. Taguchi method was employed to assess the influence of the effective parameters on the mechanical characteristics of the geopolymer composite. QUALITEK-4 software was used to create the L32 orthogonal array with 192 (96+96) geopolymer specimens and 32+32 experiments. Analysis of variance (ANOVA) was utilized to...
Ionic liquids enhanced performance of PVC gels actuator
, Article Journal of Applied Polymer Science ; Volume 138, Issue 29 , 2021 ; 00218995 (ISSN) ; Latif, A ; Hussain, K ; Shehzad, F. K ; Ali, A ; Faisal, R ; Xudong, L ; Dias, O. A. T ; Weimin, Y ; Haoyi, L ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Stimulated devices are highly demanded for actuators and artificial muscles in the recent era but susceptible to low deformation at an applied voltage. In the present work, ionic liquids (ILs) based gel films were prepared from the polyvinyl chloride (PVC), dibutyl adipate (DBA), 1-butyl, 3-methimidazolium chloride, and 1-pentyl-3-methylimidazolium hexafluorophosphate by a simple solvent evaporation method. The structural, morphological, optical, and mechanical properties of the composite PVC/ILs gel were characterized by Fourier-transform infrared spectroscopy (FTIR), Large Angle X-ray scattering (LAXS), UV–visible (UV–vis) absorption spectroscopy, scanning electron micrpscopy (SEM) and...