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micro-nanostructures
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Controlled growth of hollow polyaniline structures: From nanotubes to microspheres
, Article Polymer (United Kingdom) ; Volume 54, Issue 21 , 2013 , Pages 5586-5594 ; 00323861 (ISSN) ; Ghorbani, M ; Shojaei, A ; Sharif University of Technology
2013
Abstract
Homogeneous and fairly monosized microspherical structures of polyaniline has been synthesized using a simple soft template method with β-naphthalene sulfonic acid (β-NSA) as both the surfactant and dopant, and ammonium persulfate (APS) as the oxidant at 2-5 C. The morphology of PANI-NSA was successfully controlled from nanotubes to microsphere, by changing the synthesis conditions (i.e. pH, the concentration of surfactant and monomer, and temperature). Some mechanistic aspects of the formation of nanotubes and hollow spheres have been discussed precisely based on SEM, TEM, DLS, FTIR and UV-visible results. Moreover, synthesis was performed under acidic environment to obtain further...
Dynamic analysis of carbon nanotubes under electrostatic actuation using modified couple stress theory
, Article Acta Mechanica ; Vol. 225, Issue 6 , June , 2014 , pp. 1523-1535 ; Online ISSN: 1619-6937 ; Rastgoo, A ; Ahmadian, M. T ; Mashhadi, M. M ; Sharif University of Technology
Abstract
Modified couple stress theory is a size-dependent theorem capturing the micro/nanoscale effects influencing the mechanical behaviors of the micro- and nanostructures. In this paper, it is applied to investigate the nonlinear vibration of carbon nanotubes under step DC voltage. The vibration, natural frequencies and dynamic pull-in characteristics of the carbon nanotubes are studied in detail. Moreover, the effects of various boundary conditions and geometries are scrutinized on the dynamic characteristics. The results reveal that application of this theory leads to the higher values of the natural frequencies and dynamic pull-in voltages
Dynamic behaviours of carbon nanotubes under dc voltage based on strain gradient theory
, Article Journal of Physics D: Applied Physics ; Volume 46, Issue 40 , 2013 ; 00223727 (ISSN) ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
2013
Abstract
The paper deals with scrutinizing the vibration and dynamic pull-in behaviours of carbon nanotubes with different dimensions and boundary conditions. The strain gradient theory as a nonclassical elasticity theorem is applied in this research to compensate the limitations of the classical theories in predicting the mechanical behaviours of the micro- and nanostructures in general and carbon nanotubes, in particular under electrostatic actuation. The results reveal that the mechanical properties of carbon nanotube (CNTs) computed using the strain gradient theory differ significantly with those obtained from the classical theory. The strain gradient theory leads to higher stiffness and pull-in...
Naphtha hydrodesulfurization over micro and nanostructure MoO3 catalysts
, Article Scientia Iranica ; Volume 18, Issue 3 C , June , 2011 , Pages 479-485 ; 10263098 (ISSN) ; Kazemeini, M ; Rashidi, A. M ; Jozani, Kh. J ; Sharif University of Technology
2011
Abstract
Highly active unsupported MoO3 and Co -MoO3 catalysts were prepared by a simple solution reaction method in the presence of different organic additives. Catalysts were characterized by the XRD, BET surface area measurement, SEM and TEM techniques. Results suggested that utilizing different additives produced different morphologies OfMoO3 microstructures. Optimizing reaction conditions was found to produce more active molybdenum oxide nanoparticles when urea and PEG200 additives were utilized. XRD and TEM results indicated crystal growth restriction after cobalt incorporation. Catalytic activities of prepared materials were evaluated in the hydrodesulfurization reaction of Naphtha. Products...
Application of [M(en)3]3[Fe(ox)3]2 (M = Zn, Cd, Ni) complexes as new precursor for the synthesis of ferrite micro/nanostructures
, Article Advanced Powder Technology ; Volume 27, Issue 2 , 2016 , Pages 388-394 ; 09218831 (ISSN) ; Mohandes, F ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2016
Abstract
This work presents solid-state thermal decomposition synthesis of transition metal ferrites (MFe2O4, M = Zn, Ni, Cd). In this method, binary complexes of [Zn(en)3]3[Fe(ox)3]2, [Cd(en)3]3[Fe(ox)3]2 and [Ni(en)3]3[Fe(ox)3]2 (where en = ethylenediamine and ox = oxalate) are introduced as new single-source precursors to fabricate ZnFe2O4, CdFe2O4 and NiFe2O4 micro/nanostructures, respectively. X-ray powder diffraction (XRD) patterns show that pure CdFe2O4 and NiFe2O4 are formed by thermal decomposition of the single-source precursors at 800°C. When thermal decomposition of [Zn(en)3]3[Fe(ox)3]2 complex is carried out at 700 and 800°C, the final products are composed of ZnFe2O4 and metal oxides....
Design and fabrication of a highly efficient, stable and durable new wettability coated stainless steel mesh for oil/water separation
, Article Materials Letters ; Volume 256 , 2019 ; 0167577X (ISSN) ; Azad, M ; Amirpoor, S ; Siavash Moakhar, R ; Dolati, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The separation of water-oil mixtures has attracted widespread attention because of the increasing amounts of oily wastewater produced from the daily activities of humans and different industrial processes. Therefore, the development of facile and efficient oil-water separation technologies is imperative. In this work, a new highly superhydrophilic-superoleophobic coated stainless steel mesh was fabricated using virtue of the surface modification of poly (BzVimBr-Vim)@PFOA@SiO2 nanoparticles (NPs) through a facile preparation process. The new fabricated superhydrophilic and highly oleophobic coating exhibits good adhesive properties. The oil contact angle (OCA) and water contact angle (WCA)...
Developing a new superhydrophilic and superoleophobic poly(4-(1-vinyl-1H-imidazol-3-ium-3-yl) butane-1-sulfonate): vinyl imidazole@Perfluorooctanoic acid@SiO2 coated stainless steel mesh for highly efficient, stable, and durable oil/water separation
, Article Journal of Coatings Technology and Research ; 2020 ; Siavash Moakhar, R ; Amirpoor, S ; Azad, M ; Dolati, A ; Sharif University of Technology
Springer
2020
Abstract
The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of...
Bioinspired multifunctional TiO2 hierarchical micro/nanostructures with tunable improved bone cell growth and inhibited bacteria adhesion
, Article Ceramics International ; Volume 46, Issue 7 , 2020 , Pages 9669-9679 ; Bagheri, R ; Vossoughi, M ; Ahmadi Seyedkhani, S ; Samadikuchaksaraei, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Two main origins of failure for hard tissue replacements are structural loosening and prosthetic implant infections (PIIs). Bioinspired multifunctional TiO2 hierarchical micro/nanostructures of conical-shaped TiO2 (CTO), regular TiO2 nanotubes (RTO) and irregular TiO2 nanotubes (ITO) with tunable improved cell growth and inhibited bacteria adhesion were synthesized. CTO and ITO samples indicated superhydrophilicity with contact angles of less than 5°. The MTT assay demonstrated excellent biological performance for RTO and CTO sample with 98.1% and 103.1% of cell viability, respectively. The bridging force for osteoblast cell attachment onto the synthesized porous coatings was presented as a...