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Preparation and morphological study of epoxy/silane modified nanoclay nanocomposites
, Article Asian Journal of Chemistry ; Volume 22, Issue 1 , 2010 , Pages 797-807 ; 09707077 (ISSN) ; Bazgir, S ; Tamizifar, M ; Nemati, A ; Arzanp, K ; Sharif University of Technology
2010
Abstract
Epoxy-clay nanocomposites were prepared using silane modified montmorillonite. The clay was first purified using a 1-inch hydrocyclon apparatus. The purified clay was modified with various amounts of (γ)-3-aminopropyltrimethoxysilane as a modifier. The synthesized organoclay was mixed and swollen by a mixture of epoxy resin and stoichiometric amount of curing agent at different temperature, mixing time and agitation. Finally, the compounds were cured in an oven at 90 °C for 2 h. The nanostructure materials were characterized using X-ray diffraction and transmission electron microscopy. The X-ray diffraction patterns showed that the impurities and large particles (greater than 5 microns) are...
Removal of fluoride from wastewater by natural and modified nano clinoptilolite zeolite
, Article Journal of Water and Environmental Nanotechnology ; Volume 5, Issue 3 , 2020 , Pages 270-282 ; Charkhi, A ; Kazemeini, M ; Yousefi, T ; Sharif University of Technology
Iranian Environmental Mutagen Society
2020
Abstract
In this study adsorption of fluoride ion from high-fluorine solutions (<2000 ppm) using the natural and modified ground clinoptilolite is investigated. These low-cost adsorbents are carefully characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermos-gravimetry (TGA) and differential scanning calorimeter analysis (DSC). In order to enhance the fluoride removal capacity of natural zeolite, it is milled into nano-powders and modified using hexadecyltriammoniumions (HDTMA+). The kinetic, equilibrium, and thermodynamic of fluoride adsorption are measured and described by the well-known...
Simultaneous dual-functional photocatalysis by g-C3N4-based nanostructures
, Article ACS ES and T Engineering ; Volume 2, Issue 4 , 2022 , Pages 564-585 ; 26900645 (ISSN) ; Zaker Moshfegh, A ; Habibi Yangjeh, A ; Sillanpää, M ; Sharif University of Technology
American Chemical Society
2022
Abstract
Heterogeneous photocatalytic reactions have experienced many efforts in developing new materials to tackle environmental and energy crises through utilizing appropriate photocatalysts in wastewater treatment, H2 generation, organic transformations, CO2 reduction, N2 photofixation, and biomass conversion. While these processes are addressed in the literature separately, a recent innovative viewpoint is to employ a photocatalytic system to achieve simultaneously two or more functions. The challenging point is that the combination of two functions in one photocatalytic system requires a novel design and engineering of an appropriate semiconductor photocatalyst with special characteristics for...
Study the effect of architectural modification on fracture behavior of Al-DRA composite [electronic resource]
, Article Mechanics of Advanced Materials and Structures ; September 2014, Volume 21, Issue 8, pages 662-668 ; Khalili, S ; Bagheri, R ; Simchi, A. (Abdolreza) ; Sharif University of Technology
Abstract
An architectural modification method was utilized to improve fracture toughness of discontinuously reinforced aluminum (DRA) composites. Al-DRA composites having a structure similar to that of reinforced concrete were fabricated. The number of reinforcing DRA rods within Al matrix and volume fraction of SiC particles in DRA were altered to evaluate their effect on fracture behavior of these materials. It was found that architectural modification does not have any destructive influence on elastic modulus and yield strength of the composite. Moreover, the success of this method on toughness improvement strongly depends on the occurrence of debonding between Al and DRA regions upon loading
Effect of CO2-laser irradiation on properties and performance of thin-film composite polyamide reverse osmosis membrane
, Article Korean Journal of Chemical Engineering ; Volume 33, Issue 3 , 2016 , Pages 1028-1036 ; 02561115 (ISSN) ; Mousavi, S. A ; Farhadi, F ; Vatanpour, V ; Sabzi, B ; Chenari, Z ; Sharif University of Technology
Springer New York LLC
2016
Abstract
CO2-laser irradiation was used to modify the surface properties of thin-film composite (TFC) polyamide reverse osmosis (RO) membranes. These membranes were first synthesized via interfacial polymerization of m-phenylenediamine (MPD) monomers and trimesoyl chloride (TMC) over porous polysulfone ultrafiltration support, followed by a CO2-irradiation. AFM, ATR-FTIR, SEM and contact angle measurements were used to characterize the surface properties of these membranes. The ATR-FTIR results indicated that CO2-laser irradiation did not induce any functional groups on the membrane surface. However, it was found that the laser irradiation enhanced the NaCl salt rejection and slightly reduced the...
Practical techniques for improving the performance of polymeric membranes and processes for protein separation and purification
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 37, Issue 2 , February , 2018 , Pages 1-23 ; 10219986 (ISSN) ; Minooei, F ; Hosseini, S. S ; Sharif University of Technology
Iranian Journal of Chemistry and Chemical Engineering
2018
Abstract
Protein separation and purification technologies play an essential role in various industries including but not limited to pharmaceuticals, dairy as well as the food sector. Accordingly, a wide variety of techniques such as chromatography and electrophoresis have been developed and utilized extensively over the years for this purpose. Despite their widespread acceptance, conventional techniques still suffer from major limitations and complexities such as short lifetime, low productivity, high-pressure drop and difficulty in scale-up among others. Membrane separation processes have received significant attention in recent years as a promising alternative that can potentially overcome the...
Recent developments in graphene and graphene oxide: properties, synthesis, and modifications: a review
, Article ChemistrySelect ; Volume 5, Issue 33 , 2020 , Pages 10200-10219 ; Abbaspour, S ; Abdolahi Sadatlu, M. A ; Mirkiani, S ; Ghasemi, A ; Hoseini Ghahfarokhi, M ; Mozaffari, N ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
Wiley-Blackwell
2020
Abstract
Graphene was first discovered as a sheet structure mechanically exfoliated from a block of graphite, but in recent years researchers have extended their investigations into this two-dimensional carbon nanostructure. Various applications of graphene-based materials have included electronics, photonics, optoelectronics, sensors, and drug / gene delivery systems. These single atom carbon layers have the potential to be formed in different morphologies e. g., quantum dots, nanosheets, and nanoparticles, which can be tailored to achieve new breakthrough innovations. Nowadays, the utilization of graphene-based nanomaterials in medicine is a hot research topic. This review discusses the structure,...
Quantum secret sharing based on reusable Greenberger-Horne-Zeilinger states as secure carriers
, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 67, Issue 4 , 2003 , Pages 443021-443024 ; 10502947 (ISSN) ; Karimipour, V ; Sharif University of Technology
American Physical Society
2003
Abstract
A protocol for quantum secret sharing based on reusable entangled state was presented. In this protocol, a sequence of bits was transmitted to two parties so that they can recover half of the bits independently. The security of the protocol against eavesdropping and against cheating by one of the receivers was also discussed
Synthesis of Silica Nanoparticles Modified with Alumina and Its Performance in Compressive Strength of Concrete
, M.Sc. Thesis Sharif University of Technology ; Sajadi, Ali Akbar (Supervisor) ; Ghanbari, Bahram (Supervisor)
Abstract
Silica nanoparticles is one of the most important mineral particles. In this study, Sodium silicate, Sulfuric acid and Sodium aluminate is used in order to synthesis of the modified Silica nanoparticles. The effects of temperature, reaction time and the molar ratio of regents were tested and optimized. Synthesized nanoparticles were characterized by use of XRD, FT-IR and SEM techniques. The results show that by controlling the reaction conditions, nanoparticles with an average size of 26.2 nm is obtained. The increase of temperature and reaction time alters the structure of the particles of amorphous state to a crystalline needles. The particle surface modification process was performed by...
Time Travel: The Paradoxes of Freedom
, M.Sc. Thesis Sharif University of Technology ; Taheri Khorramabadi, Ali (Supervisor)
Abstract
The possibility of time travel in modern physics based on the theory of relativity has led to the study of this issue from various aspects. In this research, the metaphysical possibility of time travel will be examined and therefore its physical and technological possibility is out of the subject of this research. Metaphysical possibility is also considered to mean the compatibility of time travel with the laws of metaphysics. The metaphysical possibility of time travel is challenged by the paradoxes that arise from it. These paradoxes, despite their great diversity, fall into four general categories: Temporal Paradoxes, The paradoxes of freedom, The paradoxes of Causal, and The paradoxes of...
Direct dyes removal using modified magnetic ferrite nanoparticle
, Article Journal of Environmental Health Science and Engineering ; Vol. 12, Issue. 1 , 28 May , 2014 ; ISSN: 2052336X ; Abdi, J ; Bastani, D ; Sharif University of Technology
Abstract
The magnetic adsorbent nanoparticle was modified using cationic surface active agent. Zinc ferrite nanoparticle and cetyl trimethylammonium bromide were used as an adsorbent and a surface active agent, respectively. Dye removal ability of the surface modified nanoparticle as an adsorbent was investigated. Direct Green 6(DG6), Direct Red 31 (DR31) and Direct Red 23 (DR23) were used. The characteristics of the adsorbent were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of adsorbent dosage, initial dye concentration and salt was evaluated. In ternary system, dye removal of the adsorbent at 90, 120, 150 and 200 mg/L...
Preparation and primary evaluation of 66Ga-DTPA-chitosan in fibrosarcoma bearing mice
, Article Nukleonika ; Volume 56, Issue 1 , 2011 , Pages 41-47 ; 00295922 (ISSN) ; Pourjavadi, A ; Sharif University of Technology
Abstract
Chitosan was chemically modified by diethylenetetraaminepentaacetic acid (DTPA) in different degrees of modification (DM = 6.1, 10.3, 15.7 and 20.9%). DTPA-chitosans were radiolabeled with gallium-66 radionuclide. The effect of several factors on labeling yield such as degree of modification, acidity and concentration of DTPA-chitosan solution, contact time and radioactivity was investigated. Radiolabeled DTPA chitosans were intratumorally injected to fibrosarcoma bearing mice and the leakage of radioactivity from the injection site was evaluated. In comparison with chitosan, all DTPA chitosans showed better efficiency in preventing the leakage of radioactivity from tumor lesion and...
Enhancing CO2/N2 adsorption selectivity via post-synthetic modification of NH2-UiO-66(Zr)
, Article Microporous and Mesoporous Materials ; Volume 257 , February , 2018 , Pages 193-201 ; 13871811 (ISSN) ; Eskandari, A ; Shojaei, A ; Mousavi, S. A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
A metal organic framework (MOF) modified with amino group (NH2-UiO-66) was functionalized with glycidyl methacrylate (GMA) via ring opening reaction between the amine species in the framework and epoxy groups in GMA. The products were characterized by X-ray powder diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and N2 adsorption–desorption measurements to monitor their textural properties before and after functionalization. The BET surface area, pore volume, and pore...
Morphology modification of the iron fumarate MIL-88A metal–organic framework using formic acid and acetic acid as modulators
, Article European Journal of Inorganic Chemistry ; Volume 2018, Issue 18 , 2018 , Pages 1909-1915 ; 14341948 (ISSN) ; Zebarjad, S. M ; Madaah Hosseini, H. R ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Metal–organic frameworks (MOFs) are best known for their great structural diversity. The uniformity in the properties of MOFs is mainly governed by the size and morphology of the particles. In the present research, iron-MIL-88A was prepared by a modulator-assisted solvothermal method, and the role of modulating agents in the formation process of MOF particles was investigated. Acetic acid and formic acid were chosen as monoligand modulating agents. The changes in morphology and size distribution of the products were scrutinized by using SEM micrographs. Both modulators clearly interfered with the crystallization process through their attachment to the reactive sites. At low modulator...
Proposals for modification of Iranian bitumen to meet the climatic requirements of Iran
, Article Construction and Building Materials ; Volume 23, Issue 6 , 2009 , Pages 2141-2150 ; 09500618 (ISSN) ; Tabatabaee, N ; Sharif University of Technology
2009
Abstract
In this research, bitumen from seven Iranian bitumen production plants were tested and characterized according to the Superpave performance grading (PG) system. The study compared the results of this classification with the 13 performance grade binders required for specific climatic zones in Iran. A set of modifiers, as well as laboratory air blowing, were used to generate the required PG binders. The modifiers used were crumb rubber, gilsonite, polyphosphoric acid, and styrene-butadiene-styrene (SBS). It was found that the variety of available binders is not adequate to fully cover the required PGs. © 2008 Elsevier Ltd. All rights reserved
Development of a rheological model for polymeric fluids based on FENE model
, Article Polyolefins Journal ; Volume 6, Issue 1 , 2019 , Pages 95-106 ; 23222212 (ISSN) ; Ahmad Ramazani, S. A ; Davachi, S. M ; Sharif University of Technology
Iran Polymer and Petrochemical Institute
2019
Abstract
Rheological models for polymer solutions and melts based on the finitely extensible non-linear elastic (FENE) dumbbell theory are reviewed in this study. The FENE-P model that is a well-known Peterlin approximation of the FENE model, indicates noticeable deviation from original FENE predictions and also experimental results, especially in the transient flow. In addition, both FENE and FENE-P models have some shortcomings from the point of view of theory. To overcome these shortcomings, a new approximation of the FENE spring force has been established. It has been used to develop a modified constitutive rheological model for polymeric fluids. In the procedure of modeling, the effect of...
A study on the concentration-dependent relaxometric transition in manganese oxide nanocolloid as mri contrast agent
, Article ChemistrySelect ; Volume 4, Issue 25 , 2019 , Pages 7596-7601 ; 23656549 (ISSN) ; Malek, M ; Hosseini, H. R. M ; Delavari H, H ; Vahdatkhah, P ; Sharif University of Technology
Wiley-Blackwell
2019
Abstract
A green precipitation method has been used for the synthesis of ultra-small APTMS-mPEG conjugated Mn3O4 nanoparticles. Spherical cores in the uniform size of 4±1 nm were characterized by HRTEM. Zeta potential of −45 mV and the invariant turbidimetry results during the time, confirmed super-stability of the colloids. MRI relaxometry by 1.5 T scanner represented two values of r1= 8.23 s−1mM−1 and r1=7.3 s−1mM−1 for diluted and concentrated samples. The r2/r1 ratio was also decreased from 11.86 to 6.9 by dilution of colloids. Particle aggregation and motional narrowing phenomena led to a dual T1/T2 contrast agent in the Mn ion concentrations of more than 0.2 mM. The optimum concentration of Mn...
Polymer matrix nanocomposites for heavy metal adsorption: a review
, Article Journal of the Iranian Chemical Society ; Volume 17, Issue 6 , 31 January , 2020 , Pages 1259-1281 ; Keikavousi Behbahan, A ; Sharif University of Technology
Springer
2020
Abstract
Heavy metals belong to a group of lethal environmental pollutants. Ongoing efforts targeted at safeguarding public health have led to considerable attention being focused on methods that allow efficient extraction of these toxic substances. Polymer nanocomposites (PNCs) with their special characteristics are a class of adsorbents that demonstrate high potential for use in heavy metal extraction. As this process of removal is predominantly governed by adsorption, various parameters in PNCs’ chemical structure, as well as the metal solutions, can have a significant effect on the adsorption process. Herein, this review undertakes a survey of recently developed PNCs and their metal adsorption...
Ductility reduction factor of MDOF shear-building structures
, Article Journal of Earthquake Engineering ; Volume 5, Issue 3 , 2001 , Pages 425-440 ; 13632469 (ISSN) ; Mohammadi, R. K ; Sharif University of Technology
2001
Abstract
In this paper, the results of recent studies on inelastic seismic response of MDOF shear-building structures are presented. In the last few decades, the concept of response modification factor R has been introduced and developed to account for inelastic nonlinear behaviour of structures under earthquakes. In this paper, an attempt has been made to adjust and extend this concept through introducing a modifying factor RT. This factor is used for dynamic analysis of MDOF structures, including the calculation of inelastic response spectra. Sensitivity analysis was carried out to identify the parameters that have influence on RT. It has been demonstratec that RT is predominantly a function of...
Ductility reduction factor of mdof shear-building structures
, Article Journal of Earthquake Engineering ; Volume 5, Issue 3 , 2001 , Pages 425-440 ; 13632469 (ISSN) ; Mohammadi, R. K ; Sharif University of Technology
2001
Abstract
In this paper, the results of recent studies on inelastic seismic response of MDOF shear- building structures are presented. In the last few decades, the concept of response modification factor R has been introduced and developed to account for inelastic nonlinear behaviour of structures under earthquakes. In this paper, an attempt has been made to adjust and extend this concept through introducing a modifying factor Rt This factor is used for dynamic analysis of MDOF structures, including the calculation of inelastic response spectra. Sensitivity analysis was carried out to identify the parameters that have influence on RT- It has been demonstrated that Rt is predominantly a function of...