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single-walled-carbon
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Simulation of Fluid Flow in Nonstraight Nanochannels
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor)
Abstract
Understanding the flow of liquids and particularly water in nanochannels is important for scientific and technological applications, such as for filtration and drug delivery. In this study, we perform molecular dynamics simulations to investigate the transfer of single-file water molecules across straight or nonstraight single-walled carbon nanotubes (SWCNTs). In contrast with the macroscopic scenario, the nonstraight nanostructure can increase the water permeation. Remarkably, compared with the straight SWCNT, the nonstraight SWCNT with the minimal bending angle of 30° in the simulations can enhance the water transport up to 3.9 times. Also increasing length and diameter of carbon nanotubes...
Chemical Modification of Glassy Carbon Electrode by Carbon Nanostructures/Conductive Polymers Composites and Its Application in The Study of Electrochemical Behaviour and Determination of Salbutamol and Isoprenaline
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
In the first part of thesis, the electropolymerization of pyrrole was performed in the presence of new coccine (NC) as a dopant anion on the surface of the electrode precoated with SWCNT. The modified electrode was used to study the voltammetric response of salbutamol (SAL). The results showed a remarkable increase in the anodic peak current of SAL in comparison to the bare GCE. The surface morphology PPY/CNT/GCE was thoroughly characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Under the optimized analysis conditions, the modified electrode showed two linear dynamic ranges of 0.02 – 0.1 μM and 0.1-10 μM with a detection limit of 6 nM for the...
Site-specific protein conjugation onto fluorescent single-walled carbon nanotubes
, Article Chemistry of Materials ; Volume 32, Issue 20 , 2020 , Pages 8798-8807 ; Wu, S. J ; Rahnamaee, S. Y ; Schuergers, N ; Boghossian, A. A ; Sharif University of Technology
American Chemical Society
2020
Abstract
Semiconducting single-walled carbon nanotubes (SWCNTs) are among the few photostable optical emitters that are ideal for sensing, imaging, drug delivery, and monitoring of protein activity. These applications often require strategies for immobilizing proteins onto the nanotube while preserving the optical properties of the SWCNTs. Site-specific and oriented immobilization strategies, in particular, offer advantages for improving sensor and optical signaling responses. In this study, we demonstrate site-specific protein immobilization of a model of enhanced yellow fluorescent protein with a single engineered cysteine residue, using either single-stranded DNA or a pyrene-containing linker to...
A novel nonlinear constitutive relation for graphene and its consequence for developing closed-form expressions for Young's modulus and critical buckling strain of single-walled carbon nanotubes
, Article Acta Mechanica ; Volume 222, Issue 1-2 , 2011 , Pages 91-101 ; 00015970 (ISSN) ; Delfani, M. R ; Sharif University of Technology
2011
Abstract
Carbon nanotubes (CNTs) are viewed as rolled graphene. Thus, an appropriate formulation describing the behavior of CNTs must contain the key information about both their initial configuration as graphene and final configuration as CNT.On this note, to date, somemodels, in particular based on the Cauchy- Born rule, for the description of CNTs behavior exist. A simplifying assumption in some of these models is that the length and perimeter of the CNT equal the corresponding dimensions of the unrolled initial configuration, thus neglecting the induced hoop and longitudinal strains. On the other hand, the present work offers a purely nonlinear continuum model suitable for the description of the...
DFT study of NH3(H2O) n=0,1,2,3 complex adsorption on the (8, 0) single-walled carbon nanotube
, Article Computational Materials Science ; Volume 48, Issue 3 , 2010 , Pages 655-657 ; 09270256 (ISSN) ; Beheshtian, J ; Parsafar, G ; Hadipour, N. L ; Sharif University of Technology
Abstract
Theoretical study of NH3(H2O) n=0,1,2,3 adsorption on (8, 0) carbon nanotube was performed at the X3LYP/6-31G* level of density functional theory (DFT). The tube-NH3 interaction was discussed in the terms of binding energy (EB), coupling energy (EC), charge density, molecular orbitals, and dipole moments. The results reveal that addition of water molecules to tube-NH3 system increases the interaction between tube and ammonia molecule
Vibrational analysis of single-walled carbon nanotubes using beam element
, Article Thin-Walled Structures ; Volume 47, Issue 6-7 , 2009 , Pages 646-652 ; 02638231 (ISSN) ; Ahmadian, M. T ; Vafai, A ; Sharif University of Technology
2009
Abstract
Vibrational analysis of single-walled carbon nanotubes (SWCNTs) is performed using a finite element method (FEM). To this end, the vibrational behavior of bridge and cantilever SWCNTs with different side lengths and diameters is modeled by three-dimensional elastic beams and point masses. The beam element elastic properties are calculated by considering mechanical characteristics of the covalent bonds between the carbon atoms in the hexagonal lattice. The mass of each beam element is assumed as point masses at nodes coinciding with the carbon atoms. Implementing the atomistic simulation approach, the natural frequencies of zigzag and armchair SWCNTs are computed. It is observed that the...
Development of an equation to predict radial modulus of elasticity for single-walled carbon nanotubes
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 222, Issue 6 , 2008 , Pages 1109-1115 ; 09544062 (ISSN) ; Ahmadian, M. T ; Gerami, A ; Sharif University of Technology
2008
Abstract
Finite element (FE) method is used to model radial deformation of single-walled carbon nanotube (SWCNT) under hydrostatic pressure. Elastic deformation of the nanostructure is simulated via elastic beams. Properties of the beam element are calculated by considering the stiffness of the covalent bonds between the carbon atoms in the hexagonal lattice. By applying the beam elements in a three-dimensional space, elastic properties of the SWCNT in transverse direction are obtained. In this regard, influences of diameter and tube wall thickness on the radial and circumferential elastic moduli of zigzag and armchair SWCNTs are considered. It is observed that there is a good agreement between the...
Finite element model of SWCNT under hydrostatic pressure
, Article AIP Conference Proceedings, 10 April 2007 through 12 April 2007, Sharjah ; Volume 929 , 2007 , Pages 82-88 ; 0094243X (ISSN) ; 0735404399 (ISBN); 9780735404397 (ISBN) ; Ahmadian, M. T ; Sharif University of Technology
2007
Abstract
A finite element technique is used to mimic radial deformation of single-walled carbon nanotubes under hydrostatic pressure. The elastic deformation of nanotubes is modeled via elastic beams. Properties of the beam element are evaluated by considering characteristics of the covalent bonds between the carbon atoms in a hexagonal lattice. Applying the beam model in a three dimensional space, the elastic properties of the nanotube in the transverse direction are evaluated. The effects of diameter and wall thickness on the radial and circumferential elastic moduli of zigzag and armchair nanotubes are considered. Results are in good agreement with molecular structural mechanics data in the...
The effective mechanical properties and the interfacial characterization of CNT reinforced nanocomposites
, Article Proceedings of SPIE - The International Society for Optical Engineering, 9 March 2009 through 11 March 2009, San Diego, CA ; Volume 7294 , 2009 ; 0277786X (ISSN); 9780819475541 (ISBN) ; Naghdabadi, R ; The International Society for Optical Engineering (SPIE) ; Sharif University of Technology
2009
Abstract
A small volume fraction of Carbon Nanotubes (CNTs) added in a polymeric matrix increases significantly the mechanical properties of the polymers. It is experimentally determined from the TEM images of CNT-based nanocomposites that nanotubes don't stand straight in their embedded matrix and they have some curvature in their shape. The load transfer mechanism between CNT and polymer matrix is also one of the most important issues which is not understood explicitly, yet. In this paper a wavy Single Walled Carbon Nanotube (SWCNT) is modeled as inclusion in a polymer matrix and its effective mechanical properties is studied. This model is based on using 3-D Representive Volume Element (RVE) with...
Stability analysis of carbon nanotubes under electric fields and compressive loading
, Article Journal of Physics D: Applied Physics ; Volume 41, Issue 20 , 2008 ; 00223727 (ISSN) ; Ozmaian, M ; Naghdabadi, R ; Sharif University of Technology
2008
Abstract
The mechanical stability of conductive, single-walled carbon nanotubes (SWCNTs) under applied electric field and compressive loading is investigated. The distribution of electric charges on the nanotube surface is determined by employing a method based on the classical electrostatic theory. For mechanical stability analysis, a hybrid atomistic-structural element is proposed, which takes into account the nonlinear features of the stability. Nonlinear stability analysis based on an iterative solution procedure is used to determine the buckling force. The coupling between electrical and mechanical models is accomplished by adding Coulomb interactions to the mechanical model. The results show...
Dynamic stability analysis of single walled carbon nanocone conveying fluid
, Article Computational Materials Science ; Volume 113 , 2016 , Pages 123-132 ; 09270256 (ISSN) ; Noorian, M. A ; Haddadpour, H ; Fotouhi, M. M ; Sharif University of Technology
Elsevier
2016
Abstract
This report aims the study of dynamic stability of single walled carbon nanocone for some axial length conditions and declination angles of 60°, 120°and 240°. For dynamic stability analysis of Single Walled Carbon Nanocone (SWCNC), the mode shapes and frequencies of the carbon nanocone are extracted using the molecular mechanics approach. The mechanical properties of SWCNC were obtained by the Molecular Mechanics (MM) method. The obtained parameters are used for extraction of the conical shell virtual model of nanocone with the same dimensions. The equations of coupled fluid-structural dynamics of SWCNC are derived using the modal expansion for the structural displacements of the conical...
Free vibrations analysis of carbon nanotubes resting on winkler foundations based on nonlocal models
, Article Physica B: Condensed Matter ; Volume 484 , 2016 , Pages 83-94 ; 09214526 (ISSN) ; Torkaman Asadi, M. A ; Firouz Abadi, R. D ; Kouchakzadeh, M. A ; Sharif University of Technology
Elsevier
Abstract
In the present study, free vibrations of single walled carbon nanotubes (SWCNT) on an elastic foundation is investigated by nonlocal theory of elasticity with both beam and shell models. The nonlocal boundary conditions are derived explicitly and effectiveness of nonlocal parameter appearing in nonlocal boundary conditions is studied. Also it is demonstrated that the beam model is comparatively incapable of capturing size effects while shell model captures size effects more precisely. Moreover, the effects of some parameters such as mechanical properties, foundation stiffness, length and radius ratios on the natural frequencies are studied and some conclusions are drawn
Investigation of quantum conductance in semiconductor single-wall carbon nanotubes: Effect of strain and impurity
, Article Journal of Applied Physics ; Volume 110, Issue 6 , 2011 ; 00218979 (ISSN) ; Faez, R ; Pazoki, M ; Karamitaheri, H ; Sarvari, R ; Sharif University of Technology
2011
Abstract
In this paper the effect of strain and impurity on the quantum conductance of semiconducting carbon nanotubes (CNTs) have been studied by ab-initio calculations. The effect of strain and impurity on the CNT conducting behavior and physical characteristics, like density of states (DOS), band structure, and atomic local density of state (LDOS), is considered and discussed separately and simultaneously. Our results show that the quantum conductance of semiconductor CNTs is increased by compression strain, elongation strain, and replacing nitrogen and boron doping in its structure. The amount of increasing in the conductance depends on the type of strain and impurity. Conductance of CNT can be...
Simulation of biomanipulation using molecular dynamics
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 9, Issue PARTS A AND B , 2012 , Pages 137-143 ; 9780791845257 (ISBN) ; Mahboobi, S. H ; Mahjour, M. A ; Meghdari, A ; Sharif University of Technology
2012
Abstract
In this paper, the simulation of biomolecules manipulation using molecular dynamics (MD) is studied. In order to investigate the manipulation behavior, we have used the ubiquitin as biomolecule, a single-walled carbon nanotube (SWCNT) as manipulation probe, a two-layer graphene sheet as substrate. Along this line, a series of simulations are conducted to study the effects of different conditions on the success of manipulation process. These conditions include tip diameter, vertical gap between the tip and substrate, initial orientation of protein, and the tip position with respect to the biomolecule
Vibrational behavior of defective and repaired carbon nanotubes under thermal loading: A stochastic molecular mechanics study
, Article Mechanics of Materials ; Volume 163 , 2021 ; 01676636 (ISSN) ; Moradi, K ; Zeraati, A. S ; Hosseinabadi, H. G ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Carbon nanotubes (CNTs) are promising candidates for high-resolution mass nanosensors owing to their unique vibrational behavior. The structural characteristic (e.g. defect type and density) and working temperature have a significant effect on the natural frequency of CNT-based sensors. Herein, a stochastic approach based on novel finite element and molecular mechanics simulations is implemented to model the effect of temperature and structural characteristics of single-wall CNTs including defects (vacancy defect with different densities) and chirality (zigzag and armchair) on their vibrational behavior. The results show that the vacancy defects exert a significant deterioration of the...
Bode stability analysis for single wall carbon nanotube interconnects used in 3D-VLSI circuits
, Article World Academy of Science, Engineering and Technology ; Volume 77 , 2011 , Pages 568-571 ; 2010376X (ISSN) ; Faez, R ; Davoodi, B ; Farrokhi, M ; Sharif University of Technology
2011
Abstract
Bode stability analysis based on transmission line modeling (TLM) for single wall carbon nanotube (SWCNT) interconnects used in 3D-VLSI circuits is investigated for the first time. In this analysis, the dependence of the degree of relative stability for SWCNT interconnects on the geometry of each tube has been acquired. It is shown that, increasing the length and diameter of each tube, SWCNT interconnects become more stable
Stability of single-walled carbon nanopeapods under combined axial compressive load and external pressure
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 41, Issue 3 , 2009 , Pages 513-517 ; 13869477 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
Elsevier
2009
Abstract
In this paper, the axial stability of single-walled carbon nanopeapods is studied based on an elastic continuum shell model. In order to model the non-bonded van der Waals interactions between host carbon nanotube and guest fullerenes, an equivalent pressure distribution is proposed and incorporated in the model. Deriving an explicit equation for the determination of critical axial load, it is concluded that the axial stability of a single-walled carbon nanopeapod is less than that of a carbon nanotube under otherwise identical conditions. In addition, it is shown that applying external pressure to the carbon nanopeapod decreases the axial compressive stability through reducing the critical...
Stability of C60-peapods under hydrostatic pressure
, Article Acta Materialia ; Volume 55, Issue 16 , 2007 , Pages 5483-5488 ; 13596454 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
2007
Abstract
The stability of single-walled carbon nanopeapods under hydrostatic pressure is investigated using a continuum-based elastic shell model. The model incorporates nonbonded van der Waals interactions between the nested fullerenes and the host carbon nanotube. By deriving an explicit equation, it is shown that the critical hydrostatic pressure for the onset of structural instability of a completely packed C60@(10,10) nanopeapod is ∼1.11 GPa, while for the case of the pristine host (10,10) nanotube it is ∼1.84 GPa. Thus, it is concluded that the fullerene encapsulation weakens the host nanotube under hydrostatic pressure. In addition, it is quantitatively shown that any decrease in packing...
A numerical study on the influence of interface recombination on performance of carbon nanotube/GaAs solar cells
, Article Optical and Quantum Electronics ; Volume 48, Issue 8 , 2016 ; 03068919 (ISSN) ; Ghaffari, S ; Rezaei, E ; Sharif University of Technology
Springer New York LLC
Abstract
Carbon nanotubes (CNT) have unique electronic properties and remarkable optical properties. Despite of on layer thickness of CNTs, it has able to absorb photons from visible to far infrared and terahertz. These unique properties lets to create heterojunction devices by semiconductor/CNTs or metal/CNTs junctions e.g. photodiodes, sensor and heterojunction solar cell. The CNTs can play the role of a heterojunction component for charge separation as a high conductive network for charge transport and as a transparent electrode for light illumination and charge collection. The main objective of the present article is to establish a relation between interface recombination and the characteristics...
The effect of Pd addition to Fe as catalysts on growth of carbon nanotubes by TCVD method
, Article Applied Surface Science ; Volume 254, Issue 20 , 15 August , 2008 , Pages 6416-6421 ; 01694332 (ISSN) ; Reyhani, A ; Iraji zad, A ; Sharif University of Technology
Elsevier
2008
Abstract
The effects of Pd addition to Fe (Pd/Fe = 0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (920 and 970 °C) on density, diameter and growth mode of carbon nanotubes (CNTs) have been studied. SEM observations and TG analyses confirmed that the CNT yields depend on Pd/Fe ratios as (7.5/2.5) > (5/5) > Pd > (2.5/7.5) > Fe at both growth temperatures. TEM data showed that addition of Pd results in tip growth mode. From Raman spectroscopy data, the order of samples' structural quality (I G /I D ratio) are Fe > Pd/Fe (2.5/7.5) > (5/5) > (7.5/2.5) > Pd and the I G /I D ratios increase by decreasing the growth temperature. Films with higher concentration of Fe (Pd/Fe = 0, 2.5/7.5) contain some...