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multiwalled-carbon-nanotubes
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Vibration and Stability Analysis of DWCNT-Based Spinning Nanobearings
, Article International Journal of Structural Stability and Dynamics ; 2016 ; 02194554 (ISSN) ; Mohammad Khani, H ; Rahmanian, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2016
Abstract
This paper aims at investigating free vibrations and stability of double-walled carbon nanotube (DWCNT)-based spinning nanobearings. The so-called nanobearing consists of two coaxial carbon nanotubes (CNTs) where either of the two CNTs can be a rotor while the other takes the role of stator. Euler–Bernoulli beam model along with the Eringen’s nonlocal theory of elasticity are employed to obtain governing equations of transverse vibrations for the CNTs. The coupling of the two CNTs originates from the van-der-Waals (vdW) forcing present in the interface of the two CNTs. The coupling is taken into account as distributed spring foundation with an equivalent elastic stiffness. Based on the...
Preparation of ultrahigh-molecular-weight polyethylene/carbon nanotube nanocomposites with a Ziegler-Natta catalytic system and investigation of their thermal and mechanical properties
, Article Journal of Applied Polymer Science ; Volume 125, Issue SUPPL. 1 , 2012 , Pages E453-E461 ; 00218995 (ISSN) ; Ramazani, S. A. A ; Izadi, H ; Sharif University of Technology
Wiley
2012
Abstract
In this research, ultrahigh-molecular-weight polyethylene (UHMWPE)/multiwalled carbon nanotube (MWCNT) nanocomposites with different nanotube concentrations (0.5, 1.5, 2.5, and 3.5 wt %) were prepared via in situ polymerization with a novel, bisupported Ziegler-Natta catalytic system. Magnesium ethoxide [Mg(OEt) 2] and surface-functionalized MWCNTs were used as the support of the catalyst. Titanium tetrachloride (TiCl 4) accompanied by triethylaluminum constituted the Ziegler-Natta catalytic system. Preparation of the catalyst and the polymerization were carried out in the slurry phase under an argon atmosphere. Support of the catalyst on the MWCNTs was investigated with Fourier transform...
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
Thermal degradation behavior and kinetic analysis of ultra high molecular weight polyethylene based multi-walled carbon nanotube nanocomposites prepared via in-situ polymerization
, Article Journal of Macromolecular Science, Part A: Pure and Applied Chemistry ; Volume 49, Issue 9 , 2012 , Pages 749-757 ; 10601325 (ISSN) ; Saadatabadi, A. R ; Khorasheh, F ; Sharif University of Technology
T&F
2012
Abstract
Thermal degradation behavior of multi-wall carbon nanotubes (MWCNTs)/ultra high molecular weight polyethylene (UHMWPE) nanocomposites, with different nanotubes contents (0.5, 1.5 and 3.5 wt%) prepared via in-situ polymerization technique have been investigated using thermal gravimetric analysis (TGA). TGA spectra revealed that these nanocomposites had enhanced thermal stability and no significant mass loss (<0.4 wt%) occurred up to 350°C. Thermal degradation of these UHMWPE/MWCNT nanocomposites was investigated in terms of parameters such as the onset temperature of degradation (T 10), the decomposition temperature at 50% wt loss (T 50), the degradation temperature of maximum rate of the...
Electrodeposition of various au nanostructures on aligned carbon nanotubes as highly sensitive nanoelectrode ensembles
, Article Journal of Materials Engineering and Performance ; Volume 24, Issue 5 , May , 2015 , Pages 2005-2015 ; 10599495 (ISSN) ; Afshar, A ; Dolati, A ; Sharif University of Technology
Springer New York LLC
2015
Abstract
An efficient method has been developed to synthesize well-aligned multi-walled carbon nanotubes (MWCNTs) on a conductive Ta substrate by chemical vapor deposition. Free-standing MWCNTs arrays were functionalized through electrochemical oxidation with the formation of hydroxyl and carboxyl functional groups. Facile template-free electrochemical routes were then developed for the shape-selective synthesis of less-common Au nanostructures, including flower, sphere, dendrite, rod, sheet, and cabbage onto the aligned MWCNTs at room temperature. Especially, among all the synthesis methods for Au nanocrystals, this is the first report using electrochemical technique to synthesize wide variety...
Removal of benzoic acid from industrial wastewater using metal organic frameworks: equilibrium, kinetic and thermodynamic study
, Article Journal of Porous Materials ; Volume 24, Issue 1 , 2017 , Pages 165-178 ; 13802224 (ISSN) ; Safekordi, A. A ; Khorasheh, F ; Sharif University of Technology
Springer New York LLC
2017
Abstract
In this work, the adsorption of benzoic acid (BA) over metal organic framework of chromium-benzenedicarboxylates (MIL-101) is reported for the first time. The influences of pH, contact time, initial concentration, and temperature of BA solution on the adsorption behavior were investigated. The Langmuir adsorption isotherm was adequate to represent the experimental data (R2 > 0.99) and the adsorption kinetics was well-represented by a pseudo-second order kinetic model (R2 > 0.96). The zeta potential of MIL-101 decreased with increasing pH confirming the importance of electrostatic interactions between MIL-101 and BA as well as the importance of the large pore volume (1.32 m3/g) and large...
Nitrogen-doped carbon nanotubes for heat transfer applications: Enhancement of conduction and convection properties of water/N-CNT nanofluid
, Article Journal of Thermal Analysis and Calorimetry ; Volume 138, Issue 1 , 2019 , Pages 69-79 ; 13886150 (ISSN) ; Askari, S ; Ghasemy, E ; Rashidi, A ; Ettefaghi, E ; Sharif University of Technology
Springer Netherlands
2019
Abstract
In this research, it is aimed to enhance the heat transfer properties of the carbon nanotubes through nitrogen doping. To this end, nitrogen-doped multiwall carbon nanotubes (N-CNTs) were synthesized via chemical vapor deposition method. For supplying carbon and nitrogen during the synthesis of N-CNTs, camphor and urea were used, respectively, at 1000 °C over Co–Mo/MgO nanocatalyst in a hydrogen atmosphere. N-CNTs with three different nitrogen loadings of 0.56, 0.98, and 1.38 mass% were synthesized, after which, water/N-CNT nanofluids of these three samples with concentrations of 0.1, 0.2, and 0.5 mass% were prepared. To obtain a stable nanofluid, N-CNTs were functionalized by nitric acid...
Green carbon-based nanocomposite biomaterials through the lens of microscopes
, Article Emergent Materials ; Volume 5, Issue 3 , 2022 , Pages 665-671 ; 25225731 (ISSN) ; Ahmadi, S ; Rabiee, M ; Bagherzadeh, M ; Vahabi, H ; Jouyandeh, M ; Saeb, M. R ; Sharif University of Technology
Springer Nature
2022
Abstract
In this work, a green synthesis method was designed and practiced to develop bioactive and biocompatible carbon-based nanocomposites biomaterials. ZnO nanoparticles were synthesized in assistance of leaf extracts and added to a composite nanostructure composed of the reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNT). The resulting green nanocomposite revealed ability to make π-π interactions, hydrogen bonding, and van der Waals interactions with the doxorubicin (DOX). Then, the surface morphology of the synthesized nanocomposite was investigated, and the interrelationship between the surface morphology, relative cell viability, and drug uptake and release behavior were...
Enhancing the photocatalytic performance of Ag3PO4 by incorporating g-C3N4 and MWCNTs: Optimisation of removal of Acid Blue 92
, Article Progress in Reaction Kinetics and Mechanism ; Volume 41, Issue 3 , 2016 , Pages 277-288 ; 14686783 (ISSN) ; Armandsefat, F ; Mohaghegh, N ; Ahmadinasab, N ; Sharif University of Technology
Science Reviews 2000 Ltd
2016
Abstract
The main aim of the present study was to enhance the degradation capacity of Acid Blue 92 (AB92) by visible-light-active Ag3PO4 nanocomposites based on g-C3N4 and Multiwalled Carbon Nanotubes (MWCNTs). The nanocomposites were fabricated through a tunable in situ deposition method. The properties of the resulting samples were investigated by X-ray diffraction, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity results revealed that the Ag3PO4/g-C3N4 heterojunction inorganic/organic composite exhibited an improvement in both efficiency and the rate of AB92 photodegradation in comparison with the others. The enhanced photocatalytic...
A continuum constitutive model for mechanical behavior of 5052 resin epoxy containing various percentages of MWCNTs
, Article Journal of Composite Materials ; Volume 51, Issue 17 , 2017 , Pages 2423-2434 ; 00219983 (ISSN) ; Toozandehjani, H ; Ashouri Choshali, H ; Boroumand Azad, S ; Sharif University of Technology
SAGE Publications Ltd
2017
Abstract
In this article, a continuum-based constitutive model is developed to predict the mechanical behavior of 5052 resin epoxy reinforced by multiwalled carbon nanotubes (MWCNTs) based on experimentally generated data. For this purpose, MWCNTs/epoxy specimens with various percentages of functionalized and nonfunctionalized MWCNTs are prepared. The SEM graphs indicate that functionalization leads to a better bound between epoxy and MWCNTs and a higher level of dispersion. The specimens are then tested under standard ASTM D638-02 a procedure and their true plastic stress–strain curves are extracted. Investigations on experimentally generated data reveal that a wt% dependent equation which is...
RuO2 /MWCNT/ stainless steel mesh as a novel positive electrode in vanadium redox flow batteries
,
Article
RSC Advances
;
Volume 5, Issue 84
,
Aug
,
2015
,
Pages 68378-68384
;
20462069 (ISSN)
; Faraji, M
;
Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
The present work describes the preparation and electrochemical characterization of RuO2 /MWCNT/Stainless Steel Mesh (SSM) electrode as compared with a MWCNT/SSM electrode in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). The electrochemical characterization of prepared electrode was carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The electrochemical activity of MWCNT/SSM modified with RuO2 as positive electrode in a VRFB was notably improved. The RuO2 -included electrodes demonstrated high peak current ratio, small peak potential difference and high electron...
Electrodeposited multi-walled carbon nanotubes on Ag-loaded TiO2 nanotubes/Ti plates as a new photocatalyst for dye degradation
, Article RSC Advances ; Volume 5, Issue 56 , 2015 , Pages 44840-44846 ; 20462069 (ISSN) ; Faraji, M ; Gobal, F ; Gholami, M. R ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
MWCNTs/Ag/TiO2NTs plates were synthesized via electrochemical reduction of functionalized multiwalled carbon nanotubes (MWCNTs) on Ag/TiO2NTs. The loading of silver nanoparticles was carried out by electroless reduction of Ag1+ onto TiO2 nanotubes previously formed by anodizing titanium. The SEM analysis revealed that MWCNTs were loaded significantly on the as-prepared Ag/TiO2NTs, where nanoparticles of Ag had grown on the walls of TiO2NTs. The photocatalytic activity of the synthesized plates was evaluated by the photodegradation of Methyl Orange (MO) dye under UV light irradiation. The results indicated that the MWCNTs/Ag/TiO2NTs demonstrated improved efficiency for MO photodegradation in...
A simple label-free electrochemical DNA biosensor based on carbon nanotube-DNA interaction
, Article RSC Advances ; Volume 6, Issue 19 , 2016 , Pages 15592-15598 ; 20462069 (ISSN) ; Salimian, R ; Kalhor, H. R ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A simple platform based on a hairpin oligonucleotide switch and multi-walled carbon nanotubes (MWCNTs) for the ultrasensitive detection of specific DNA sequences has been developed. In this approach, the π-stacking interaction of single-strand DNA-MWCNT was employed to construct an electrochemical DNA biosensor. Changes to the surface conductivity, based on the MWCNT replacement, were monitored by using the electrochemical species [Fe(CN)6]3-/4- as a redox probe. Morphological and voltammetric characterizations of the electrode surface were performed using atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and...
Platinum nanoparticles with superacid-doped polyvinylpyrrolidone coated carbon nanotubes: Electrocatalyst for oxygen reduction reaction in high-temperature proton exchange membrane fuel cell
, Article RSC Advances ; Volume 6, Issue 48 , 2016 , Pages 41937-41946 ; 20462069 (ISSN) ; Saievar Iranizad, E ; Bayat, A ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
In order to improve the catalytic activity and durability of proton-exchange-membrane-fuel-cells (PEMFCs), Nafion-free Pt-based catalyst using the superacid-doped polymer coated multiwall carbon nanotubes (MWCNTs) was investigated. The modification and nano polymerization of MWCNTs were developed by polyvinylpyrrolidone (PVP). The following observations were made in the presence of polymer: better dispersion of MWCNTs, higher thermal stability of MWCNT/PVP than that of pristine MWCNT up to 450 °C as tested by thermal gravimetric analysis (TGA), homogeneous distribution of Pt without agglomeration as observed by transmission electron microscope (TEM), and not too much difference in Pt loading...
Efficient dye-sensitized solar cells based on CNT-derived TiO2 nanotubes and Nb-doped TiO2 nanoparticles
, Article RSC Advances ; Volume 6, Issue 103 , 2016 , Pages 101737-101744 ; 20462069 (ISSN) ; Mohammadi, M.R ; Afshar, A ; Chau-Nan Hong, F ; Jeng, Y. R ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
We report a new facile strategy to enhance the efficiency of TiO2 dye-sensitized solar cells (DSSCs) using Nb-doped TiO2 photoelectrodes with carbon nanotube-derived TiO2 nanotubes (CDTs). Multi-walled carbon nanotubes (CNTs) with an average diameter of 80 nm are used as the template to produce CDTs through facile sol-gel and oxidation processes at 600 °C. Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) analyses reveal that the synthesized CDTs have a uniform thickness of 60-120 nm and a crystallite size of 17 nm. We prepare Nb-doped TiO2 nanoparticles with different atomic ratios of 0-4 at% Nb and test them as photo-electrodes to investigate the doping...
Experimental investigation and finite element modelling of PMMA/carbon nanotube nanobiocomposites for bone cement applications
, Article Soft Matter ; Volume 18, Issue 36 , 2022 , Pages 6800-6811 ; 1744683X (ISSN) ; Khakbiz, M ; Chagami, M ; Bagheri, R ; Chashmi, F. S ; Akbari, B ; Shakibania, S ; Lee, K. B ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Multi-walled carbon nanotubes (MWCNTs) are one of the preferred candidates for reinforcing polymeric nanobiocomposites, such as acrylic bone type of cement. In this study, at first, bulk samples of the reinforced polymethylmethacrylate (PMMA) matrix were prepared with 0.1, 0.25, and 0.5 wt per wt% of MWCNTs by the casting method. Tensile and three-point bending tests were performed to determine the essential mechanical properties of bone cement, such as tensile and bending strengths. The tensile fracture surfaces were investigated by scanning electron microscopy (SEM). The commercial software (Abaqus) was used to conduct finite element analysis (FEA) by constructing a representative volume...
The TCVD growth of CNTs over copper-silver-palladium nanoparticles prepared by DC magnetron sputtering
, Article Acta Physica Polonica A ; Volume 137, Issue 6 , 2020 , Pages 1075-1079 ; Mardani, M ; Shakoury, R ; Sharif University of Technology
Polish Academy of Sciences
2020
Abstract
In this study, we investigate the use of catalytic copper-silver-palladium substrates for the growth of multiwalled carbon nanotubes via the thermal chemical vapor deposition. These layers are comprised of nanocrystals of Cu2O, CuO, Ag, Pd, Cu, and PdO and were grown using a DC magnetron sputtering method. Scanning electron microscopy characterizations confirmed the significant growth of carbon nanotubes on the catalytic layer. A comparison of the growth of nanotubes indicated that the thickness of the catalytic layers has a significant impact on the quality and the diameter of the carbon nanotubes. Two major peaks were seen in the Raman spectrum. The formation of graphite multiwalled...
Mechanical characteristics of cement paste in the presence of carbon nanotubes and silica oxide nanoparticles: An experimental study
, Article Materials ; Volume 14, Issue 6 , 2021 ; 19961944 (ISSN) ; Farhangi, V ; Farani, M. R ; Joshaghani, A ; Zadehmohamad, M ; Ahmadzadeh, M ; Sharif University of Technology
MDPI AG
2021
Abstract
Considering the remarkable characteristics of nanomaterials, previous research studies investigated the effects of incorporating different types of these materials on improving the concrete properties. However, further studies are required to evaluate the complementary hybridization and synergistic influence of nanomaterials. In this research, the combined effect of adding nano silica particles (NS) and multi-walled carbon nanotubes (MWCNT) on enhancing both the compressive and flexural strengths of the cement paste was investigated. Moreover, the morphology of the interface between cement paste and aggregates was studied by scanning electron microscopy (SEM). The mixtures were prepared...
Synthesis and characterization of anatase-coated multiwall carbon nanotube for improvement of photocatalytic activity
, Article International Journal of Engineering, Transactions A: Basics ; Volume 30, Issue 4 , 2017 , Pages 543-550 ; 17281431 (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center
2017
Abstract
Sol-gel technique was used to coat multiwall carbon nanotubes (MWCNTs) with anatase titania to increasing the surface area and improve the photocatalytic activity of TiO2. Room temperature ballistic conduct of MWCNT combined with semiconducting behavior of anatase brought about a photocatalytic improvement of ∼37 % with respect to the highest methyl orange decolorization flair. For characterization and photocatalytic efficiency determination, X-ray diffraction (XRD), field emission (FE) scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS) and ultraviolet visible (UV-vis) spectroscopy were rehearsed. Attachment of anatase...
Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes
, Article Journal of Industrial and Engineering Chemistry ; Volume 28 , August , 2015 , Pages 202-210 ; 1226086X (ISSN) ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry
2015
Abstract
Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.%...