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Visible light switchable bR/TiO2 nanostructured photoanodes for bio-inspired solar energy conversion
, Article RSC Advances ; Volume 5, Issue 24 , Jan , 2015 , Pages 18642-18646 ; 20462069 (ISSN) ; Janfaza, S ; Irani, R ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Today, regarding the limitation and environmental side effects of fossil fuel resources, solar hydrogen production is one of the main interests in the energy research area. The development of visible light sensitized semiconductors based on non-toxic components, low cost and available bio-species is an ongoing approach for H2 generation based on water splitting reactions. Here, two different morphologies of TiO2 photoanodes, nanoparticulated and nanotubular, have been modified with simply extracted bacteriorhodopsin (bR) without any linker. Achieving a significant enhancement in photoconversion efficiency of TiO2 photoanodes, η% was increased from 2.9 to 16.5 by bR addition to the TiO2...
Neural implant stimulation based on TiO2 nanostructured arrays; A multiphysics modeling verification
, Article IECBES 2014, Conference Proceedings - 2014 IEEE Conference on Biomedical Engineering and Sciences: "Miri, Where Engineering in Medicine and Biology and Humanity Meet", 8 December 2014 through 10 December 2014 ; December , 2015 , Pages 677-680 ; 9781479940844 (ISBN) ; Mohammadpour, R ; Amiri, K ; Silterra; University of Malaya ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Exploiting of the nanostructure arrays as a promising candidate for excitation of neural cells has been analyzed. Based on the importance of the coupling effect between electrode and neuron, a multiphyscis modeling approach has been proposed. The model incorporates theoretically both structural effects (size, geometry) and electrophysiological effects. The system of equations for proposed model has been solved numerically using Finite Element Method for Poisson equation and Finite Difference Method for Cable equation. In this regards we have combined the system of equations in COMSOL platform with Matlab interface accordingly. We have analyzed the effect of excitation of neuron with an extra...
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...
Contribution of ordered-inordered phenomenon within the interphase region toward increasing elastic modulus in CNT/polymer nanocomposites
, Article Materials Science and Technology Conference and Exhibition 2015, MS and T 2015, 4 October 2015 through 8 October 2015 ; Volume 1 , October , 2015 , Pages 595-602 ; 9781510813939 (ISBN) ; Goodarzi Hosseinabadi, H ; NACE International ; Sharif University of Technology
Association for Iron and Steel Technology, AISTECH
2015
Abstract
Exceptional mechanical properties of carbon nanotubes (CNTs) such as high elastic modulus, stiffness and tensile strength have made them as promising reinforcement in polymer nanocomposite systems. The characteristics of CNTs/polymer interphase region directly affect the efficiency of nanotubes for improving the nanocomposite mechanical properties. In this work, the influence of chains alignment within the interphase region on elastic response of the nanocomposite is assessed using a novel ordered-inordered approach. The applicability of the presented approach is examined by implementing the approach on a series of reported data available in the literature. The effects of CNT content,...
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
The effect of nanoparticles on the mass transfer in Liquid–Liquid extraction
, Article Chemical Engineering Communications ; Volume 202, Issue 5 , Sep , 2015 , Pages 600-605 ; 00986445 (ISSN) ; Heydari Nasab, A ; Bastani, D ; Seife Kordi, A. A ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
This article investigates the effect of nanoparticles on mass transfer in the liquid–liquid extraction for the chemical system of n-butanol–succinic acid–water. For this purpose, nanofluids containing various concentrations of ZnO, carbon nanotubes (CNT), and TiO2 nanoparticles in water, as base fluid, were prepared. To examine the flow mode effect on mass transfer rate, different fluid modes including dropping and jetting were employed in the process. Results show that mass transfer rate enhancement depends on the kinds and the concentration of nanoparticles and the modes of flow. It was observed that after adding nanoparticles, the mass transfer rate significantly increases up to two-fold...
Plasma effects on anti-felting properties of wool fabrics
, Article Surface and Coatings Technology ; Volume 205, Issue SUPPL. 1 , December , 2010 , Pages S349-S354 ; 02578972 (ISSN) ; Rashidi, A ; Ghoranneviss, M ; Anvari, A ; Wiener, J ; Sharif University of Technology
2010
Abstract
Low temperature plasma (LTP) is nowadays an intensively investigated superficial treatment of wool. In this work we have investigated the effect of LTP on wool fabric under different conditions. The effect of the position of samples inside the reactor and the kind of gases used as discharge medium has been also investigated. The results show that not only the topography of the surface is modified but also the chemical composition of the surface. It is shown that the hydrophilicity of the samples and also their shrink resistance and anti-felting behavior have improved significantly under LTP treatment. The results show that the shrinkage of 30.1% for untreated samples has reduced to about...
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...
Temperature-Dependent Comparison between Delay of CNT and Copper Interconnects
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 24, Issue 2 , 2016 , Pages 803-807 ; 10638210 (ISSN) ; Sarvari, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
The performance of gigascale integration chips improves by cryogenic technologies such as subambient cooling. In these conditions, interconnects may perform at temperatures as low as 50 K. However, the local temperature of interconnects could easily be as high as 600 K at high-temperature chips. In this brief, we investigated the impact of temperature on delay of local, intermediate, and global interconnects of International Technology Roadmap for Semiconductors Node 2024. This is done for different values of interconnect width and length, nanotube diameter, and percentage of metallic carbon nanotubes (CNTs) in a grown bundle. Results are compared with those of copper counterpart. We showed...
ZnO-PEDOT core-shell nanowires: An ultrafast, high contrast and transparent electrochromic display
, Article Solar Energy Materials and Solar Cells ; Volume 145 , 2016 , Pages 200-205 ; 09270248 (ISSN) ; Safarian, S ; Kolahdouz, M ; Fathipour, M ; Ahamdi, V ; Sharif University of Technology
Elsevier
Abstract
We report fabrication of ultrafast and high contrast transparent electrochromic device desired for display application using nanostructured electrode. To this end, poly (3,4-ethylenedioxythiophene) (PEDOT) nanotubes were synthesized by simple electrochemical polymerization method on hydrothermally grown ZnO nanowires array as electrode. The PEDOT nanotubes of 20 nm average wall thickness characterized by SEM, TEM and EDS. The manufactured cell was subjected to electrochemical test and spectrophotometery that showed high contrast of 54% during ultrafast switching time of <2.2 ms. In addition, high coloration efficiency of 234 cm2/C, ultrahigh diffusion coefficient of 2.01×10-4 cm2/s and...
Toughening of epoxy nanocomposites: Nano and hybrid effects
, Article Polymer Reviews ; Volume 56, Issue 1 , 2016 , Pages 70-112 ; 15583724 (ISSN) ; Mai, Y. W ; Bagheri, R ; Pearson, R. A ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
In this paper, we review recent progress made in the field of epoxy-based binary and ternary nanocomposites containing three-, two-, and one-dimensional (i.e., 3D-, 2D-, and 1D) nano-size fillers with a special focus on their fracture behaviors. Despite investigations conducted so far to evaluate the crack-resistance of epoxy nanocomposites and attempts made to clarify the controlling toughening mechanisms of these materials, some questions remain unsolved. It is shown that silica nanoparticles can be as effective as rubber particles in improving the fracture toughness/energy; but incorporation of carbon nanotubes (CNTs) or clay platelets in epoxy matrices delays crack growth only modestly....
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...
Molecular dynamics study of bio-manipulation in aqueous media
, Article Micro and Nano Letters ; Volume 11, Issue 1 , 2016 , Pages 9-14 ; 17500443 (ISSN) ; Pishkenari, H. N ; Mahboobi, S. H ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
Nano-manipulation is one of the most important aspects of nano-robotics and nano-assembly. The positioning process is considered by many researches to be one of the most important parts of nano-assembly, but has been poorly investigated, particularly for biologic samples. This Letter is devoted to modelling the process of positioning a biomolecule with atomic force microscopy (AFM) in an aqueous media using molecular dynamics simulations. Carbon nanotube (CNT) and graphite sheet are selected as AFM tip and substrate, respectively. To consider the effects of the medium on the manipulation, several models for decreasing the calculations including implicit, coarse grained, and all-atom methods...
Oxidation of H2S to elemental sulfur over alumina-based nanocatalysts: Synthesis and physiochemical evaluations
, Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1160-1174 ; 10263098 (ISSN) ; Kazemeini, M ; Fattahi, M ; Rashidi, A. M ; Vafajoo, L ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
In this paper, oxidation of H2S into elemental sulfur over synthesized aluminabased nanocatalysts was physiochemically investigated and the results were compared with a commercial Claus catalyst. The wet chemical, co-precipitation, and spray pyrolysis techniques were employed to synthesize several alumina nanostructures. Then, the SEM, XRD, and ASAP analysis methods were utilized to characterize in order to choose the best nanocatalyst. The sulfur and H2S contents were determined through the standard UOP techniques. Amongst the synthesized materials, Al2o3-supported sodium oxide prepared through the wet chemical, and Al2o3 nanocatalysts via spray pyrolysis methods were the most active...
Fabrication mechanism of nanostructured HA/TNTs biomedical coatings: an improvement in nanomechanical and in vitro biological responses
, Article Journal of Materials Science: Materials in Medicine ; Volume 27, Issue 10 , 2016 ; 09574530 (ISSN) ; Riahi, Z ; Eslami, A ; Sadrnezhaad, S. K ; Sharif University of Technology
Springer New York LLC
2016
Abstract
In this paper, a mechanism for fabrication of nanostructured hydroxyapatite coating on TiO2 nanotubes is presented. Also, the physical, biological, and nanomechanical properties of the anodized Ti6Al4V alloy consisting TiO2 nanotubes, electrodeposited hydroxyapatite, and the hydroxyapatite/TiO2 nanotubes double layer coating on Ti6Al4V alloy implants are compared. Mean cell viability of the samples being 84.63 % for uncoated plate, 91.53 % for electrodeposited hydroxyapatite, and 94.98 % for hydroxyapatite/TiO2 nanotubes coated sample were in the acceptable range. Merely anodized prototype had the highest biocompatibility of 110 % with respect to the control sample. Bonding strength of...
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...
The Role of Carbon Nanotubes in Improving Thermal Stability of Polymeric Fluids: Experimental and Modeling
, Article Industrial and Engineering Chemistry Research ; Volume 55, Issue 27 , 2016 , Pages 7514-7534 ; 08885885 (ISSN) ; Ghotbi, C ; Tahmasbi, K ; Ghazanfari, M. H ; Sharif University of Technology
American Chemical Society
2016
Abstract
At harsh conditions of high pressure high temperature (HPHT), polymers undergo thermal degradation leading to serious loss in fluid rheological and filtration properties. Nanoparticles are the most promising additives proposed to address this challenge. The stability of nanofluids is perused from various facets including rheological and filtration properties, shale stability, and zeta potential. The presence of nanoparticles could amazingly reduce the filtration at high temperatures even by 95%, and it also had a conspicuous effect on shale stability, thermal conductivity, and zeta potential. Experimental data were fit to rheological models to determine the best models describing the...
Study of Absorption Enhancement of CO2 by SiO2, Al2O3, CNT, and Fe3O4 Nanoparticles in Water and Amine Solutions
, Article Journal of Chemical and Engineering Data ; Volume 61, Issue 4 , 2016 , Pages 1378-1387 ; 00219568 (ISSN) ; Keshavarz, P ; Ayatollahi, S ; Sharif University of Technology
American Chemical Society
Abstract
In this work, the absorption process of carbon dioxide is performed in a custom designed high pressure experimental setup in which the gas and nanofluid are in direct contact at static state in a closed vessel. The initial condition of the tests are set at 20, 30, and 40 bar and 308 K. Nanoparticles of SiO2, Al2O3, Fe3O4, and carbon nanotubes (CNTs) are dispersed in pure water to form nanofluids at concentrations of 0.02, 0.05, and 0.1 wt %. Also, CNT nanoparticle has been dispersed in methyldiethanolamine and diethanolamine aqueous solutions at the concentration of 0.02 wt %. The absorption performances of different nanofluids are compared with the base solutions and with other nanofluids...
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
Ag/TiO2-nanotube plates coated with reduced graphene oxide as photocatalysts
, Article Surface and Coatings Technology ; Volume 288 , 2016 , Pages 144-150 ; 02578972 (ISSN) ; Mohaghegh, N ; Sharif University of Technology
Elsevier
Abstract
RGO/Ag/TiO2-nanotubes/Ti plates with high photocatalytic activity were fabricated via electrochemical reduction of graphene oxide on Ag/TiO2-nanotubes. The loading of silver nanoparticles was carried out by electroless reduction of Ag1+ onto TiO2 nanotubes previously formed by anodizing titanium. Microstructure studies show that reduced graphene oxide (RGO) layers having high surface area have been deposited on the as-prepared Ag/TiO2-nanotubes, where nanoparticles of Ag had grown on the walls of TiO2-nanotubes. The results of photocatalytic experiments demonstrate that the RGO/Ag/TiO2-nanotubes/Ti plate exhibits significantly enhanced photocatalytic activity for the photocatalytic...