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nanotubes
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Highly sensitive 3D gold nanotube ensembles: Application to electrochemical determination of metronidazole
, Article Electrochimica Acta ; Volume 106 , 2013 , Pages 288-292 ; 00134686 (ISSN) ; Ghorbani, M ; Ghalkhani, M ; Vossoughi, M ; Dolati, A ; Sharif University of Technology
2013
Abstract
Three-dimensional gold nanoelectrode ensembles (3D GNE) have proven to be promising nanoelectrodes by representing much higher sensitivity compared to both their 2D nanostructures and bulk counterparts. The sensitivity of 3D gold nanotubes (GNTs) fabricated through electrodeposition inside the pores of polycarbonate templates, was examined toward metronidazole (MTZ) as one of their pharmaceutical applications. The electrochemical behavior of MTZ at the 3D GNT-modified electrode was discussed in detail through cyclic voltammetry (CV) which suggested an irreversible reduction of nitro group to the corresponding hydroxylamine and a subsequently reversible redox peak for the corresponding...
Elastic behavior of an edge dislocation inside the wall of a nanotube
, Article Scripta Materialia ; Volume 64, Issue 8 , 2011 , Pages 709-712 ; 13596462 (ISSN) ; Gutkin, M. Y ; Shodja, H. M ; Sharif University of Technology
Abstract
The problem of edge dislocation inside the wall of a multi-walled nanotube accounting for the surface effects is addressed. Within the framework of surface elasticity the stress field is obtained, using complex potentials. Furthermore, the stress field and image forces acting on the dislocation, with and without an account of the surface stress, are compared together and discussed
On the pull-in instability of double-walled carbon nanotube-based nano electromechanical systems with cross-linked walls
, Article Fullerenes Nanotubes and Carbon Nanostructures ; Volume 23, Issue 4 , Dec , 2015 , Pages 300-314 ; 1536383X (ISSN) ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
This paper presents the deflection and pull-in instability of the double-walled carbon nanotubes with different dimensions and boundary conditions. Molecular dynamic technique is applied to model the desired behaviors of the nano systems. The effects of cross-linking between the carbon walls are investigated on the pull-in charge. In addition, the influences of axial stretching on the pull-in charge and vibrational frequencies of the carbon nanotubes are scrutinized. The effects of electrostatic charge distribution on the vibration amplitude are also reported
Variational principles for stability analysis of multi-walled carbon nanotubes based on a nonlocal elastic shell model
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, Istanbul, 12 July 2010 through 14 July 2010 ; Volume 5 , 2010 , Pages 591-598 ; 9780791849194 (ISBN) ; Rafati, J ; Sharif University of Technology
2010
Abstract
The nonlocal continuum theories are capable to reflect the small length characteristic of nanostructures. In this work, variational principles are presented for the stability analysis of multi-walled carbon nanotubes under various mechanical loadings based on the nonlocal elastic Donnell's shell by the semi-inverse method. In this manner, a set of proper essential and natural boundary conditions for each layer of the multi-walled nanotube is derived
The effects of multi-walled carbon nanotubes graphitization treated with different atmospheres and electrolyte temperatures on electrochemical hydrogen storage
, Article Electrochimica Acta ; Volume 55, Issue 16 , June , 2010 , Pages 4700-4705 ; 00134686 (ISSN) ; Nozad Golikand, A ; Mortazavi, S. Z ; Irannejad, L ; Moshfegh, A. Z ; Sharif University of Technology
2010
Abstract
Using multi-walled carbon nanotubes (MWCNTs), the present study focuses on their electrochemical hydrogen storage capacities. The results showed that the hydrogen desorption process is composed of two steps with voltages around -0.75 and -0.15 V. Hydrogen adsorption at -0.15 V took place at temperatures above 30 °C, and the amount of energy required for adsorbing hydrogen was 1.68 eV. The hydrogen storage capacity increased with increasing electrolyte temperature from 30 to 60 °C in both steps. The hydrogen storage capacity of the MWCNTs treated at different atmospheres showed that the decrease in the graphitization of MWCNTs led to the increase in hydrogen adsorption. The results also...
On dynamic instability of a pressurized functionally graded carbon nanotube reinforced truncated conical shell subjected to yawed supersonic airflow
, Article Composite Structures ; Volume 153 , 2016 , Pages 938-951 ; 02638223 (ISSN) ; Asadi, H ; Wang, Q ; Sharif University of Technology
Elsevier Ltd
Abstract
The aeroelastic flutter characteristics of a functionally graded carbon nanotube reinforced composite (FG-CNTRC) truncated conical shell under simultaneous actions of a hydrostatic pressure and yawed supersonic airflow are scrutinized. The nonlinearity in geometry of the conical shell is considered in Green–Lagrange sense and the model is derived according to the Novozhilov nonlinear shell theory. The aerodynamic pressure is modeled based on the quasi-steady Krumhaar's modified supersonic piston theory by considering the effect of the panel curvature and flow yaw angle. Parametric studies are conducted to investigate the effects of boundary conditions, semi-vertex angle, distribution and...
Bridged single-walled carbon nanotube-based atomic-scale mass sensors
, Article Applied Physics A: Materials Science and Processing ; Volume 122, Issue 8 , Volume 122, Issue 8 , 2016 ; 09478396 (ISSN) ; Shaat, M ; Abdelkefi, A ; Sharif University of Technology
Springer Verlag
Abstract
The potentials of carbon nanotubes (CNTs) as mechanical resonators for atomic-scale mass sensing are presented. To this aim, a nonlocal continuum-based model is proposed to study the dynamic behavior of bridged single-walled carbon nanotube-based mass nanosensors. The carbon nanotube (CNT) is considered as an elastic Euler–Bernoulli beam with von Kármán type geometric nonlinearity. Eringen’s nonlocal elastic field theory is utilized to model the interatomic long-range interactions within the structure of the CNT. This developed model accounts for the arbitrary position of the deposited atomic-mass. The natural frequencies and associated mode shapes are determined based on an eigenvalue...
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
Effect of carbon nanotube dispersion and network formation on thermal conductivity of thermoplastic polyurethane/carbon nanotube nanocomposites
, Article Polymer Engineering and Science ; Volume 56, Issue 4 , 2016 , Pages 394-407 ; 00323888 (ISSN) ; Powell, T ; Solouki Bonab, V ; Manas Zloczower, I ; Sharif University of Technology
Abstract
Carbon nanotubes (CNTs) were dispersed without any solvent in poly(tetramethylene ether glycol), (PTMEG) well above its melting point by ultrasonication in the pulse mode and different times. The polyol/CNT suspensions were used to prepare in situ polymerized thermoplastic polyurethane TPU/CNT nanocomposites with the CNT concentration of ∼ 0.05 vol%, much below the CNT geometrical percolation threshold calculated at 0.43 vol%. Results of rotational rheological measurements and ultraviolet-visible (UV-Vis) spectroscopy analysis revealed improvement in the nanoscale CNT dispersion with sonication time. Moreover, the optical microscopic images and sedimentation behavior for these samples...
Synthesis and characterization of a new nanocomposite by filling of CNT with CoFe2O4 Magnetic nanoparticles and grafting to polymer
, Article Nano ; Volume 4, Issue 6 , 2009 , Pages 371-376 ; 17932920 (ISSN) ; Adeli, M ; Actinchap, B ; Bahari, A ; Sharif University of Technology
Abstract
In this work, the synthesis and characterization of a new nanocomposite from carbon nanotubes-graft-polymer (CNTs-g-P) is reported. The products were obtained by the filling of multi-walled carbon nanotubes (MWCNTs) (inner diameter 2040 nm) with CoFe2O4 magnetic nanoparticles, been grafted with poly (caprolactone). The filling process was carried out by using acid treatment through wet chemistry. The structure and the properties of the new nanocomposite were studied with TEM, VSM, TGA, and spectroscopic techniques. © 2009 World Scientific Publishing Company
Glassy carbon electrode modified with 3D graphene–carbon nanotube network for sensitive electrochemical determination of methotrexate
, Article Sensors and Actuators, B: Chemical ; Volume 239 , 2017 , Pages 617-627 ; 09254005 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In the present study, a 3D porous graphene-carbon nanotube (G-CNT) network is successfully constructed on the surface of glassy carbon electrode (GCE) by electrochemical co-deposition from a concentrated graphene dispersion. The large accessible surface area provided by the interpenetrated graphene backbone in one hand and the enhanced electrical conductivity of the 3D network by incorporating CNTs on the other hand, dramatically improved the electrochemical performance of GCE in determination of Methotrexate (MTX) as an important electroactive drug compound. Under the optimum conditions, the electrode modification led to a significant increase in the anodic peak current (∼25 times) along...
Synthesis of metal-organic framework hybrid nanocomposites based on GO and CNT with high adsorption capacity for dye removal
, Article Chemical Engineering Journal ; Volume 326 , 2017 , Pages 1145-1158 ; 13858947 (ISSN) ; Vossoughi, M ; Mahmoodi, N. M ; Alemzadeh, I ; Sharif University of Technology
Abstract
In this study, zeolitic imidazolate framework (ZIF-8) as a metal-organic framework (MOF) and its hybrid nanocomposites based on graphene oxide (GO) and carbon nanotubes (CNTs) were synthesized by facile method at an ambient temperature. The sufficiency of GO and CNT substrates as the main components of the composites to grow nanoscale MOFs and increase dispersive forces were investigated. The characteristics of the MOF and hybrid nanocomposites were studied using FTIR, SEM, XRD, BET and TGA techniques. The prepared nanomaterials applied as adsorbents to remove malachite green (MG) as a cationic dye from colored wastewater. The removal rates of the hybrid nanocomposites were greater than that...
Loading drug on nanostructured Ti6Al4V-HA for implant applications
, Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1159-1165 ; 1728144X (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center
2018
Abstract
Arrayed Ti6Al4V nanotubes (TNT) coated with hydroxyapatite (HA) were synthesized via electrochemical anodization method. Paracetamol was loaded onto TNT-HA electrode. Effects of anodization, nanotube formation and hydroxyapatite deposition on sorption and release of the drug were investigated. Saturation time of paracetamol on the anodized samples was 30% shorter than the hydroxyapatite-coated samples. Release behavior of the loaded drug was studied by (a) plunging the probe into phosphate buffered saline (PBS), (b) sampling the drug-loaded PBS at different times and (c) analyzing the solution via ultraviolet-visible (UV-vis) spectroscopy. Results showed that HA electrodes hold higher...
Flexible triboelectric nanogenerator based on high surface area TiO2 nanotube arrays
, Article Advanced Engineering Materials ; Volume 20, Issue 5 , May , 2018 ; 14381656 (ISSN) ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Triboelectric nanogenerators (TENGs) can harvest mechanical energy through coupling triboelectric effect and electrostatic induction. Typically, TENGs consist of organic materials, however on account of the potentially wide range of applications of TENGs as the self-powered portable/wearable electronics, biomedical devices, and sensors; semiconductor metal oxide materials can be promising candidates to be incorporating in TENG structure. Here, flexible TENG based on self-organized TiO2 nanotube arrays (TNTAs) is fabricated via anodization method. The introduced flexible large area nanotubular electrode is employed as the moving electrode in contact with Kapton film in vertical contact...
Buckling and vibration characteristics of a carbon nanotube-reinforced spinning cantilever cylindrical 3D shell conveying viscous fluid flow and carrying spring-mass systems under various temperature distributions
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 233, Issue 13 , 2019 , Pages 4590-4605 ; 09544062 (ISSN) ; Esmailpoor Hajilak, Z ; Habibi, M ; Safarpour, H ; Sharif University of Technology
SAGE Publications Ltd
2019
Abstract
In this article, buckling and vibrational behaviors of a carbon nanotube reinforced spinning cylindrical thick shell carrying spring–mass systems and conveying viscous fluid flow are investigated under various temperature distributions. Also, the installed sensors on the proposed system are considered as a tip mass. The uniform distribution and the functionally graded distribution patterns of reinforcement are considered. The modeled cylindrical thick shell and governing equations are derived by a new three-dimensional refined higher-order theory. Finally, the effects of various types of carbon nanotube reinforcements and other parameters on buckling and vibrational characteristics of the...
Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes, as a high-performance electrode for Li-ion battery and supercapacitor
, Article Electrochimica Acta ; Volume 390 , 2021 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, F ; Ghasemi, S ; Sanaee, Z ; Mohajerzadeh, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of...
Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes, as a high-performance electrode for Li-ion battery and supercapacitor
, Article Electrochimica Acta ; Volume 390 , 2021 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, F ; Ghasemi, S ; Sanaee, Z ; Mohajerzadeh, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of...
Enhancing Seebeck coefficient and electrical conductivity of polyaniline/carbon nanotube–coated thermoelectric fabric
, Article Journal of Industrial Textiles ; Volume 51, Issue 2_suppl , 2022 , Pages 3297S-3308S ; 15280837 (ISSN) ; Ramazani Saadatabadi, A ; Pourjahanbakhsh, M ; Siadati, M. H ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
In this work, flexible thermoelectric fabrics, polyester/yarn fabrics coated with polyaniline/carbon nanotube (PANI/CNT) nanocomposite, were fabricated by sequential processing: (I) polyaniline/carbon nanotube nanocomposites preparation by a one-step in-situ polymerization and (II) dip coating of a mixture solution of CNT-doped PANI on a polyester/yarn fabric. Nanocomposites were synthesized with various CNT content (0.5, 2.5, 5, and 10 wt%) and characterized using different methods. The Seebeck coefficient and electrical conductivity measurements were used to determine their thermoelectric properties. The results revealed significant improvement in both electrical conductivity and the...
Calculating the Stiffness Matrix of VACNTs Using Structural or Continuum Modelling
, M.Sc. Thesis Sharif University of Technology ; Dehghani Firouz Abadi, Ruhollah (Supervisor)
Abstract
The goal of this research is investigation and analysis of a surface consists of vertically aligned carbon nanotubes (VACNTs) using continuum mechanics modeling. Today these kinds of surfaces also known as the darkest material have a particular importance in industries. Knowing the properties of a material is one of the most important things in analysis and designing using that kind of material, so extraxting the stiffness matrix of a material could be a big step for starting analyzing it. In this thesis a lattice of VACNTs with two different layouts and several unique geometrics is simulated using molecular dynamics approach using the Lammps software. The general stiffness matrix of the...
Synthesis of PZT-CNT Hybrid Nanotubes by Sol-gel Method
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor) ; Seyyed Reyhani, Morteza (Supervisor)
Abstract
In this research, the surface of multi-walled carbon nanotubes (CNTs), as template, were coated by Lead zirconate titanate (PZT) with composition of Pb(Zr0.52Ti0.48)O3 via sol-gel process. The final product is called PZT-CNT hybrid material. For functionalizing of CNTs, benzyl alcohol was used. Simultaneous thermal analysis (STA) proved that the as-derived amorphous material crystallized at 520 ˚C. Scanning Electron Microscope (SEM) images verified the deposition of a uniform coating of PZT on the surface of CNTs and proved that the functionalizing treatment was done successfully. X-ray diffraction (XRD) showed that the crystal structure of the hybrid was tetragonal perovskite....