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    Development of Nanostructural Al-Mg-Si Alloys using ECAE and Ageing Processes

    , Ph.D. Dissertation Sharif University of Technology Vaseghi, Majid (Author) ; Karimi Taheri, Ali (Supervisor)
    The manufacture of ultra high strength materials has always been a target for aerospace and transportation industries. Currently, the limitation of energy resources even makes this goal more serious. Nowadays, more than 50% of total extrusion products are made from Al alloys and around 90% of them are the 6000 series alloys. Therefore, regarding to high strength, low weight, and hardening aluminum AA6000 alloys capabilities can play a major role in fulfilling this task. Over the last decade, a number of techniques collectively referred to as severe plastic deformation (SPD), have emerged as a promising approach for the production of bulk ultrafine-grained (UFG) nano-structured materials.... 

    Multiscale Nonlinear Finite Element Analysis of Nanostructured Materials Based on Equivalent Continuum Mechanics

    , Ph.D. Dissertation Sharif University of Technology Ghanbari, Jaafar (Author) ; Naghdabadi, Reza (Supervisor) ; Sohrabpour, Saeed (Supervisor)
    Nanostructured materials are a new kind of engineering materials which attracted researchers’ interest because of their interesting mechanical /physical properties, as well as controllable microstructural design ability for desired applications. These new materials are homogeneous at the macroscale but at the microstructural level, may have heterogeneities including common nanostructures. Because of multiscale nature of these materials, new multiscale methods should be developed and used for better understanding the behavior of them. Multiscale methods could be categorized into concurrent and hierarchical methods. In concurrent methods, the domain under study is explicitly divided into... 

    Investigation of the Performance of Microbial Fuel Cell Based on Shewanella Bacteria with the Aim of Nanostructured Materials

    , M.Sc. Thesis Sharif University of Technology Davoudi, Omid (Author) ; Yaghmaei, Soheila (Supervisor) ; Sanaee, Zeinab (Co-Supervisor)
    The development of clean, renewable and alternative sources of fossil fuels has increased in recent years due to various factors such as environmental pollution, reduced fossil fuel resources and increased energy consumption. The application of microbial fuel cells is one of the clean energy production methods using renewable sources such as municipal sewage. The microbial fuel cell converts the chemical energy stored in organic materials into electrical energy and simultaneously purifies the sewage. Increasing current density and power density are the most important challenges for microbial fuel cells. In this study, the two biocatalysts of Shewanella Oneidensis MR1 and Escherichia coli... 

    Morphological dependence of light backscattering from metallic back reflector films: Application in dye-sensitized solar cells

    , Article Physica Status Solidi (A) Applications and Materials Science ; Volume 212, Issue 4 , January , 2015 , Pages 785-790 ; 18626300 (ISSN) Sharifi, N ; Ghazyani, N ; Taghavinia, N ; Sharif University of Technology
    Wiley-VCH Verlag  2015
    Conventionally, a film of TiO2 particles of 300 nm size is employed in Dye-sensitized solar cells (DSCs) as the back reflector film to enhance the light harvesting. Perfect reflectance of silver in visible and near infrared motivates to investigate its potential as the material for the light back reflector film in DSCs. In this study, light back reflector films consisting of 300 nm-sized silver particles, as well as vacuum evaporated silver flat film, were fabricated and compared to 300 nm-sized rutile-type TiO2 particulate reflector film to study their optical aspects. Conventional TiO2 rutile-type particulate film demonstrates slightly lower performance... 

    Carbon nanoparticles in high-performance perovskite solar cells

    , Article Advanced Energy Materials ; Volume 8, Issue 12 , 2018 ; 16146832 (ISSN) Yavari, M ; Mazloum Ardakani, M ; Gholipour, S ; Marinova, N ; Delgado, J. L ; Turren Cruz, S. H ; Domanski, K ; Taghavinia, N ; Saliba, M ; Gratzel, M ; Hagfeldt, A ; Tress, W ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    In the past few years, organic–inorganic metal halide ABX3 perovskites (A = Rb, Cs, methylammonium, formamidinium (FA); B = Pb, Sn; X = Cl, Br, I) have rapidly emerged as promising materials for photovoltaic applications. Tuning the film morphology by various deposition techniques and additives is crucial to achieve solar cells with high performance and long-term stability. In this work, carbon nanoparticles (CNPs) containing functional groups are added to the perovskite precursor solution for fabrication of fluorine-doped tin oxide/TiO2/perovskite/spiro-OMeTAD/gold devices. With the addition of CNPs, the perovskite films are thermally more stable, contain larger grains, and become more... 

    Graphene oxide-l-arginine nanogel: A pH-sensitive fluorouracil nanocarrier

    , Article Biotechnology and Applied Biochemistry ; Volume 66, Issue 5 , 2019 , Pages 772-780 ; 08854513 (ISSN) Malekimusavi, H ; Ghaemi, A ; Masoudi, G ; Chogan, F ; Rashedi, H ; Yazdian, F ; Omidi, M ; Javadi, S ; Haghiralsadat, B. F ; Teimouri, M ; Faal Hamedani, N ; Sharif University of Technology
    Wiley-Blackwell Publishing Ltd  2019
    Nowadays, putting forward an accurate cancer therapy method with minimal side effects is an important topic of research. Nanostructures, for their ability in controlled and targeted drug release on specific cells, are critical materials in this field. In this study, a pH-sensitive graphene oxide-l-arginine nanogel was synthesized to carry and release 5-fluorouracil. Optimized conditions using statistical analysis, based on the maximum relative viscosity of nanogel, were evaluated: 5.489 for the concentration of l-arginine and 2.404 for pH. The prepared nanogels were characterized using scanning electron microscope and transmission electron microscope images and Fourier-transform infrared... 

    Wave propagation analysis of a spinning porous graphene nanoplatelet-reinforced nanoshell

    , Article Waves in Random and Complex Media ; Volume 31, Issue 6 , 2021 , Pages 1655-1681 ; 17455030 (ISSN) Ebrahimi, F ; Mohammadi, K ; Barouti, M. M ; Habibi, M ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    In this article, wave propagation behavior of a size-dependent spinning graphene nanoplatelet-reinforced composite (GNPRC) cylindrical nanoshell with porosity is presented. The effects of small scale are analyzed based on nonlocal strain gradient theory (NSGT), this accurate theory employs exact length scale parameter and nonlocal constant. The governing equations of GNPRC cylindrical nanoshell coupled with piezoelectric actuator (PIAC) are evolved by minimum potential energy principle and solved by the analytical method. For the first time in the current study, wave propagation-porosity behavior of a GNPRC cylindrical nanoshell coupled with PIAC is examined based on NSGT. The results show... 

    Injectable polyethylene glycol-laponite composite hydrogels as articular cartilage scaffolds with superior mechanical and rheological properties

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 66, Issue 3 , 2017 , Pages 105-114 ; 00914037 (ISSN) Nojoomi, A ; Tamjid, E ; Simchi, A ; Bonakdar, S ; Stroeve, P ; Sharif University of Technology
    Taylor and Francis Inc  2017
    In this study, injectable PEG-based hydrogels containing Laponite particles with mechanical and structural properties close to the natural articular cartilage are introduced. The nanocomposites are fabricated by imide ring opening reactions utilizing synthesized copolymers containing PEG blocks and nanoclay through a two-step thermal poly-(amic acid) process. Butane diamine is used as nucleophilic reagent and hydrogels with interconnected pores with sizes in the range of 100–250 µm are prepared. Improved viscoelastic properties compared with the conventional PEG hydrogels are shown. Evaluation of cell viability utilizing human mesenchymal stem cells determines cytocompatibility of the... 

    Nanomaterial-assisted pyrolysis of used lubricating oil and fuel recovery

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Alavi, E ; Abdoli, M. A ; Khorasheh, F ; Nezhadbahadori, F ; Bayandori Moghaddam, A ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas... 

    Biocompatible conductive alginate/polyaniline-graphene neural conduits fabricated using a facile solution extrusion technique

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2020 Bayat, A ; Ramazani Sa., A ; Sharif University of Technology
    Taylor and Francis Inc  2020
    In this study, conductive sodium alginate/polyaniline/graphene (PAG) NGCs were fabricated utilizing a straightforward solution extrusion method. The 4 point-probe test revealed that the addition of PAG has increased the conductivity of the NGCs up to 9.7 × 10−3 S.cm−1. The results also showed a remarkable increase in the Young modulus and SEM images revealed that the suggested process could produce NGCs continuously and uniformly with desirable porosity. The Fourier-transform infrared spectroscopy spectrum proved a good interaction between PAG and the polymeric matrix. Furthermore, the addition of PAG slightly prevented biodegradation of the NGCs. Finally, the cell viability assay confirmed... 

    Synthesis, characterization and mechanistic study of nano chitosan tetrazole as a novel and promising platform for CRISPR delivery

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2020 Rabiee, N ; Bagherzadeh, M ; Tavakolizadeh, M ; Pourjavadi, A ; Atarod, M ; Webster, T. J ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Here, a newly modified chitosan tetrazole was synthesized and fully characterized for CRISPR technology since by increasing the ratio of nitrogen to other elements, the interaction between the genetic material and this nanomaterial was significantly enhanced. The nanomaterial was added to HEK-293 cells for pCRISPR delivery. The nanomaterials were optimized and showed an acceptable binding ability with DNA due to its increasing zeta potential in the synthesized chitosan tetrazole in comparison with chitosan, as well as considerable transfection efficiency, more than 25%, and, thus, can be considered as a promising and also new gold-standard for the delivery of pCRISPR. © 2020 Taylor & Francis... 

    Analytical study of electro-elastic fields in quantum nanostructure solar cells: the inter-nanostructure couplings and geometrical effects

    , Article Acta Mechanica ; Volume 229, Issue 7 , 2018 , Pages 3089-3106 ; 00015970 (ISSN) Rashidinejad, E ; Naderi, A. A ; Sharif University of Technology
    Springer-Verlag Wien  2018
    Recent investigations on multifunctional piezoelectric semiconductors have shown their excellent potential as photovoltaic components in high-efficiency third-generation quantum nanostructure (QNS) solar cells. The current work is devoted to studying the electro-elastic behavior of high-density QNS photovoltaic semiconductors within which initial mismatch strains of arrays of quantum dots (QDs) or quantum wires (QWRs) induce coupled electro-mechanical fields. The inter-nanostructure couplings which are of great importance in high-density QNS arrays are incorporated in the presented analytical framework. In practice, QNSs with different geometries such as spherical, cuboidal, or pyramidal QDs... 

    Structure, swelling and mechanical behavior of a cationic full-IPN hydrogel reinforced with modified nanoclay

    , Article Iranian Polymer Journal (English Edition) ; Volume 24, Issue 5 , May , 2015 , Pages 379-388 ; 10261265 (ISSN) Kheirabadi, M ; Bagheri, R ; Kabiri, K ; Sharif University of Technology
    Springer-Verlag London Ltd  2015
    Despite various applications of hydrogels, they have poor gel strength and low resistance against crack propagation which lead to the limitation of their applications. For overcoming this inherent weakness, the current study has focused on the simultaneous utilization of interpenetrating polymer network (IPN) structure and nanocomposite hydrogels. It is known that IPN and nanocomposite gels can improve gel strength. The combination of IPN and nanocomposite structure was developed in hydrogels for improving gel strength. For this purpose, bentonite was successfully modified with a cationic surfactant, (3-methacrylamidopropyl) trimethyl ammonium chloride (MAPTAC), as intercalate, and... 

    Swelling and mechanical behavior of nanoclay reinforced hydrogel: single network vs. full interpenetrating polymer network

    , Article Polymer Bulletin ; Volume 72, Issue 7 , March , 2015 , Pages 1663-1681 ; 01700839 (ISSN) Kheirabadi, M ; Bagheri, R ; Kabiri, K ; Sharif University of Technology
    Springer Verlag  2015
    Despite the various uses of hydrogels, one of their weaknesses is the poor gel strength. To overcome this restriction, the current study has focused on simultaneously employing an interpenetrating polymer network (IPN) structure and nanocomposite hydrogels. Through this approach, the influence of nanofiller in the single network and IPN hydrogel properties was also studied in detail. For this purpose, a novel full interpenetrating polymer network (IPN) hydrogel nanocomposite based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS)/acrylic acid (AA)–sodium acrylate (AANa) was synthesized in two steps through a facile solution polymerization with incorporation of modified bentonite (MBE) as... 

    Characterization of nanocrystalline CuCo2O4 spinel prepared by sol–gel technique applicable to the SOFC interconnect coating

    , Article Applied Physics A: Materials Science and Processing ; Volume 119, Issue 2 , May , 2015 , Pages 727-734 ; 09478396 (ISSN) Paknahad, P ; Askari, M ; Ghorbanzadeh, M ; Sharif University of Technology
    Springer Verlag  2015
    CuCo2O4 spinel nanopowders were synthesized by sol–gel method. The optimal values of pH and molar ratio of citric acid to metal ions (RC), and the influence of the calcination temperature and time were investigated. As-prepared materials were characterized by XRD, TGA, DSC, FE-SEM and electrical and coefficient of thermal expansion (CTE) measurements. It was found that pH = 4.5 and RC = 1 are the optimum conditions to produce pure CuCo2O4 nanopowders. The electrical conductivity was increased remarkably from 15.2 to 27.5 S cm−1 with an increase in temperature from 500 to 800 °C. Over the temperature range of 25–800 °C, the CTE of... 

    Effect of nanoclay on improved rheology properties of polyacrylamide solutions used in enhanced oil recovery

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 5, Issue 2 , June , 2015 , Pages 189-196 ; 21900558 (ISSN) Cheraghian, G ; Khalili Nezhad, S. S ; Kamari, M ; Hemmati, M ; Masihi, M ; Bazgir, S ; Sharif University of Technology
    Springer Verlag  2015
    Recently, a renewed interest arises in the application of nanotechnology for the upstream petroleum industry. In particular, adding nanoparticles to fluids may drastically benefit enhanced oil recovery (EOR) and improve well drilling, by changing the properties of the fluid, rocks wettability alteration, advanced drag reduction, strengthening the sand consolidation, reducing the interfacial tension and increasing the mobility of the capillary trapped oil. In this study, we focus on roles of clay nano-particles on polymer viscosity. Polymer-flooding schemes for recovering residual oil have been in general less than satisfactory due to loss of chemical components by adsorption on reservoir... 

    Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

    , Article Applied Physics A: Materials Science and Processing ; Volume 123, Issue 8 , 2017 ; 09478396 (ISSN) Fazaeli, Y ; Zare, H ; Karimi, S ; Rahighi, R ; Feizi, S ; Sharif University of Technology
    Springer Verlag  2017
    In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with 68Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with 68Ga NPs (68Ga@ CdTe QDs) were found high... 

    Rapid biosorption of methylene blue by in situ cellulose-grafted poly 4-hydroxybenzoic acid magnetic nanohybrid: multivariate optimization and isotherm study

    , Article Polymer Bulletin ; Volume 75, Issue 5 , 2018 , Pages 2167-2180 ; 01700839 (ISSN) Alijani, H ; Beyki, M. H ; Kaveh, R ; Fazli, Y ; Sharif University of Technology
    Springer Verlag  2018
    In this research, an efficient biosorption system was developed for methylene blue adsorption over in situ hydrothermally synthesized magnetite 4-hydroxybenzoic acid cellulose nanohybrid. The material was characterized with EDX, VSM, FT-IR, FESEM, and TEM techniques. Results showed that the nanohybrid is a micro-cluster composed of stacked nanoscale particles. Multivariate optimization with Box–Behnken design was used to evaluate effective parameters on adsorption and their interaction. Results showed that pH, shacking time, and adsorbent dosage are effective parameters on MB adsorption. Adsorption rate is fast with equilibrium time of 5.5 min. Isotherm study revealed that the adsorption... 

    Application of nonlocal strain–stress gradient theory and GDQEM for thermo-vibration responses of a laminated composite nanoshell

    , Article Engineering with Computers ; Volume 37, Issue 4 , 2021 , Pages 3359-3374 ; 01770667 (ISSN) Moayedi, H ; Ebrahimi, F ; Habibi, M ; Safarpour, H ; Foong, L. K ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    In this article, thermal buckling and frequency analysis of a size-dependent laminated composite cylindrical nanoshell in thermal environment using nonlocal strain–stress gradient theory are presented. The thermodynamic equations of the laminated cylindrical nanoshell are based on first-order shear deformation theory, and generalized differential quadrature element method is implemented to solve these equations and obtain natural frequency and critical temperature of the presented model. The results show that by considering C–F boundary conditions and every even layers’ number, in lower value of length scale parameter, by increasing the length scale parameter, the frequency of the structure... 

    Irreversibility of nanomaterial due to MHD via numerical approach

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 144, Issue 3 , 2021 , Pages 1041-1050 ; 13886150 (ISSN) Balazadeh, N ; Shafee, A ; Tlili, I ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    In current research, MAPLE software was utilized to scrutinize the heat transfer of copper–H2O nanomaterial migration over a sheet. Entropy production in existence of magnetic field was scrutinized, and Bejan number was reported as main outputs. Converting PDEs into ODEs was done via similarity transformation, and final ODEs were analyzed via RK4. The influence of different variables, including fraction of nanomaterial and Lorentz force on flow distribution and temperature field, also on surface tension and Nu was demonstrated. Besides, Be and NG were calculated for various ranges of scrutinized variables. © 2020, Akadémiai Kiadó, Budapest, Hungary