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Tehrān, Iran

Istadeh K.H.,Iran University of Industries and Mines | Istadeh K.H.,Hamgara Company | Kalantarinejad R.,Aerospace Research Institute | Aghaei M.J.,Aerospace Research Institute | Yazdi M.R.S.,University of Tehran
Journal of Computational and Theoretical Nanoscience | Year: 2013

During the last decade, the conductometric gas nanosensor based on nanotube has brought huge attention, due to its dynamic and static sensing specifications. In spite of the fact that a sheer number of efforts have been successfully reported to detect different gases with high sensitivity, good limit of detection, and short response time, more analytical investigations are needed to define conductance change mechanism and important parameters affecting sensor performance. According to experimental limits and cost, development of this sensor needs more computational investigations to elucidate design criteria and understand effects of different parameters such as carbon nanotube type, metal carbon nanotube junction, external electric field, and type of functionalization on its performance. Here, we investigate adsorption of a hydrogen sulphide gas on carbon nanotube channel of a nanosensor using Molecular Dynamics methods and Density Functional Theory. The model comprises a semiconductor single-walled carbon nanotube interconnected between two gold electrodes on (1, 1, 1) plane. In addition, we study the effect of the carbon nanotube functional groups on adsorption of target gas and show that Amide functional groups have considerable effect on adsorption. The results show that, the carbon nanotube functionalized with amide group exhibit enhanced adsorption characteristics compared to pristine carbon nanotubes. Copyright © 2013 American Scientific Publishers. Source

Kiani F.,Iranian Space Agency | Khosravi T.,University of Tehran | Moradi F.,Iranian Space Agency | Rahbari P.,Hamgara Company | And 4 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2014

In current study, pressure-driven water flow through an arrangement of carbon nanotubes (CNTs) inside a silicon matrices is examined using non-equilibrium molecular dynamics (MD) simulations. The effects of different parameters such as CNT type (armchair (n, n), zigzag (n, 0) and chiral (m, n)), CNT diameter (ranging between 8.1 to 21.7 nm) and pressure gradient (ranging between 0.08 to 2 (1014 Pa/m)) on water transport through CNTs and salt rejection (membrane performance) were investigated. The results show that armchair CNTs with the diameter of 1.1 nm at pressure gradient of 0.6 (10 14 Pa/m) exhibit the highest permeation flux and ion rejection. Copyright © 2014 American Scientific Publishers. Source

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