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Carbon nanotube

Ajeet Kumar's picture

Microscopic definition of internal force, moment and associated stiffnesses in one-dimensional nanostructures at finite temperature

We present a one-dimensional variant of the Irving-Kirkwood-Noll procedure to derive microscopic expressions of internal contact force and moment in one-dimensional nanostructures. We show that these expressions must contain both the potential and kinetic parts: just the potential part does not yield meaningful continuum results. We further specialize these expressions for helically repeating one-dimensional nanostructures for their extension, torsion and bending deformation. As the Irving-Kirkwood-Noll procedure does not yield expressions of stiffnesses, we resort to a thermodynamic equilibrium approach to first obtain the Helmholtz free energy of the supercell of helically repeating nanostructures. We then obtain expressions of axial force, twisting moment, bending moment and the associated stiffnesses by taking the first and second derivatives of the Helmholtz free energy with respect to conjugate strain measures. The derived expressions are used in finite temperature molecular dynamics simulation to study extension, torsion and bending of single-walled carbon nanotubes and their buckling.
The article will soon appear in the Mathematics and Mechanics of Solids. The same can be accessed at the following link: https://www.researchgate.net/publication/337873624_Microscopic_definitio...

Ajeet Kumar's picture

Phonons in chiral nanorods and nanotubes: a Cosserat rod based continuum approach

A Cosserat rod based continuum approach is presented to obtain phonon dispersion curves of flexural, torsional, longitudinal, shearing and radial breathing modes in chiral nanorods and nanotubes. Upon substituting the continuum wave form in the linearized dynamic equations of stretched and twisted Cosserat rods, we obtain analytical expression of a coefficient matrix (in terms of the rod's stiffnesses, induced axial force and twisting moment) whose eigenvalues and eigenvectors give us frequencies and mode shapes, respectively, for each of the above phonon modes.

Jingjie Yeo's picture

Effects of oscillating pressure on desalination performance of transverse flow CNT membrane

https://doi.org/10.1016/j.desal.2018.03.029 In parallel with recent developments in carbon nanomaterials, there is growing interest in using these nanomaterials for desalination. To date, many studies have affirmed the potential of using such nanomaterials for constant pressure desalination operation. In this work, the performance of such membrane when subjected to oscillatory pressure at sub-nanosecond is investigated in detail.

mortezaamjadi's picture

Ultra-stretchable and skin-mountable strain sensors using carbon nanotubes–Ecoflex nanocomposites

Super-stretchable, skin-mountable, and ultra-soft strain sensors are presented by using carbon nanotube percolation networksilicone rubber nanocomposite thin films. The applicability of the
strain sensors as epidermal electronic systems, in which mechanical compliance like human skin and high stretchability (e > 100%) are required, has been explored. The sensitivity of the strain

yann.charles's picture

PostDoctoral Position on polymer composite material modeling - University Paris 13, Paris, France

no longer available.

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A 12 months post Doctoral position is avalaible on mechanical and numerical modeling fields at LSPM, univ. Paris 13, France.

The aim  is the development of a theoretical and numerical modeling approach in order to describe the mechanical properties of polymer composite material and structures reinforced by CarbonNanoTube. Once the description of mechanical properties achieved, the extension of the modeling  framework to the electrical and thermal properties and their coupling to the mechanical behavior might be considered.

upriyank's picture

3 PhD Positions: Carbon Nano-Structured Materials for Aerospace Applications


Carbon Nano-Structured Materials for Aerospace Applications: From Characterization & Multi-scale Modelling to Product Realization- A Holistic Approach

Payam Soltani's picture

Nonlinear and quasi-linear behavior of a curved carbon nanotube vibrating in an electric force field; an analytical approach

 
Nonlinear and quasi-linear behavior of a curved carbon nanotube vibrating in an electric force field; an analytical approach

 By: Payam SOLTANI, A. Kassaei, M. M. Taherian

Abstract

Kmomeni's picture

Carbon Nanohorn Reinforced Nanocomposites...

I have formulated a shear-lag model for calculating the variation of stress along carbon nanohorns (CNHs), which are conical shaped wrapped carbon sheets, embedded in an epoxy matrix under axial loading.  I found that the stress distribution along the length of CNHs depends on the cone angle of these structures and maximum normal axial stress has a smaller value in CNHs compared to a carbon nanotube (CNT) with same cross-section as of the CNH's tip.  Furthermore, I read an article stating that synthesis of CNHs are easier compared to CNTs.  However, the only article I could find which has s

Nonlinear free and forced vibration analysis of a single-walled carbon nanotube using shell model

Payam Soltani, J. Saberian, R. Bahramian, and A. Farshidianfar

 

http://fundamentaljournals.org/ijfps/archive.html#A14 

 

In this Paper, the nonlinear free and force vibration of a single-walled carbon nanotube (SWCNT) with simply supported ends is

investigated based on von Karman’s geometric nonlinearity. The SWCNT described as an individual shell and the Donnell’s

equations of cylindrical shells are used to obtain the governing equations. The Galerkin's procedure is used to discretized partial

Ajeet Kumar's picture

A one-dimensional Rod Model for Carbon Nanotubes

We recently published a paper in International Journal of Solids and Structures titled "A rod model for three dimensional deformations of single walled carbon nanotubes".(paper attached)

http://www.sciencedirect.com/science/article/pii/S0020768311002149

Jianliang Xiao's picture

van der Waals interaction controls orientations of single-walled carbon nanotubes on quartz during growth

Single-walled carbon nanotubes (SWNTs) possess extraordinary electrical and mechanical properties, with many possible applications in electronics and materials science. Dense, horizonally aligned arrays of linearly configured SWNTs represent perhaps the most attractive and scalable way to implement this class of nanomaterial in practical systems. Recent work shows that templated growth of tubes on certain crystalline substrates (e.g. quartz) yields arrays with the necessary levels of perfection, as demonstrated by the formation of devices and full systems on quartz.

NANOSHEL

NANOSHEL makes more than 50 types of products, among which the main products are nanotubes, SWCNT´s, MWCNT´s, nanoparticles,. These products are widely used in the fields such as textile industry, ceramics, chemical fiber, plastics, coatings, cosmetics, rubber, electrical and electronic equipments, electric power generation and boiler and so on.

Jianliang Xiao's picture

Mechanics of buckled carbon nanotubes on elastomeric substrates

We have studied the scaling of controlled nonlinear buckling processes in materials with dimensions in the molecular range (i.e., ~1 nm) through experimental and theoretical studies of buckling in individual single-wall carbon nanotubes on substrates of poly(dimethylsiloxane). The results show not only the ability to create and manipulate patterns of buckling at these molecular scales, but also, that analytical continuum mechanics theory can explain, quantitatively, all measurable aspects of this system.

Henry Tan's picture

carbon nanotube-reinforced composite materials

The effect of van der Waals-based interface cohesive law on carbonnanotube-reinforced composite materials

H. Tan, L. Y. Jiang, Y. Huang, B. Liu, and K. C. Hwang
Composite Science and Technology, 2007, accepted.

Young's modulus of single-walled carbon nanotubes

We report in detail that unlike other materials, carbon nanotubes are so small that changes in structure can affect the Young's modulus. The variation in modulus is attributed to differences in torsional strain, which is the dominant component of the total strain energy. Torsional strain, and correspondingly Young's modulus, increases significantly with decreasing tube diameter and increases slightly with decreasing tube helicity.  Journal of Applied Physics 84, 1939 (1998).

Carbon Nanotube Lecture on Nov 1st at MIT

Dr. John Hart from MIT is giving a carbon nanotube (CNT) tutorial at the International Symposoum on Nanomanufacturing (ISNM) at MIT on November 1st, Wednesday. Please see the following if you are interested.

 

Carbon Nanotubes: Fundamentals, synthesis, and applications

Dr. John Hart, MIT
November 1st
9.00 am - 12.30pm (with 1 break)

http://www.isnm2006.org/Professional_courses.html

Nanotube 'forest' makes super slippery surface

A material less sticky than Teflon has been created by covering a surface with a "forest" of carbon nanotubes. Newscients.com has a very interesting report. Read more...

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