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nanostructured-composites
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Preparation and Characterization of Hydroxyapatite/Polycaprolactone Nanocomposites by Sol-gel Process
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Hydroxyapatite (HA) is the most substantial mineral constituent of a bone which displays splendid biocompatibility and bioactivity properties. Nevertheless, its mechanical property is not utmost appropriate for a bone substitution. Therefore, a composite consist of HA and a biodegradable polymer is usually prepared to generate an apt bone scaffold. In the present work polycaprolactone (PCL), a newly remarkable biocompatible and biodegradable polymer, was employed as a matrix and hydroxyapatite nanoparticles and nanorods were used as a reinforcement element of the composite. HA/PCL nanocomposites were synthesized by three new in-situ sol-gel processes using a diverse range of phosphorus and...
Study of the densification of a nanostructured composite powder. part 1: effect of compaction pressure and reinforcement addition
, Article Materials Science and Engineering A ; Volume 486, Issue 1-2 , 2008 , Pages 580-584 ; 09215093 (ISSN) ; Farnoush, H ; Salahi, E ; Pourazrang, K ; Sharif University of Technology
2008
Abstract
The compressibility behavior of Al-AlN nanostructured composite powder with different amount of reinforcement content was studied. The composite powder was synthesized by blending and high-energy milling process for 25 h. Williamson-Hall method was applied to determine the crystallite size after milling process. To investigate the role of reinforcement particles in consolidation of composite powders, monolithic aluminum powder was examined. Samples were made at different pressures and relationships were established between the compaction pressure and the density of the compacts. The modified Heckel equation was used to assume the pressure effect on yield strength and then was compared with...
Zinc based Metal-organic Frame Work Nanomaterial to Remove Contaminant from Water
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Khorashe, Farhad (Supervisor) ; Mahmoodi, Niyaz Mohammad (Supervisor)
Abstract
In present work, we fabricated novel heterojunction magnetic composite and the goo visible-light-harvesting photocatalysts through integration of ZnFe2O4 and MIL-53 by facile solvothermal method. To understand physical and chemical structure prepared material and morphology of samples, The XRD,FTIR, FESEM, DRS and VSM analysis were carried out. The ZFO/M53Fe/vis-light system reveled 92.3% dye degradation which enhanced photo catalyst reactivity for the decolorization of Direct red 23 as anionic dye under irraditation of LED lamp through AOP environment friendly technology, which are significantly higher than those of pure ZFO and M53Fe semiconductors. more ever ,aforementioned composite...
Construction of Pt nanoparticle-decorated graphene nanosheets and carbon nanospheres nanocomposite-modified electrodes: Application to ultrasensitive electrochemical determination of cefepime
, Article RSC Advances ; Volume 4, Issue 15 , 2014 , Pages 7786-7794 ; ISSN: 20462069 ; Hosseini Nassab, N ; Ghalkhani, M ; Sharif University of Technology
Abstract
A novel ultrasensitive modified electrode was fabricated with a graphene nanosheets and carbon nanospheres (GNS-CNS)-based nanocomposite film as a powerful platform. Pt nanoparticles (PtNPs) were simply electrodeposited onto the GNS-CNS-coated glassy carbon electrode creating a PtNPs/GNS-CNS hybrid nanocomposite modified electrode. Scanning electron microscopy, energy dispersive X-ray spectroscopy and linear sweep voltammetry (LSV) techniques were used for the characterization of the prepared modified electrode. The results of investigation of electrochemical response characteristics of cefepime (CP) revealed a considerable improvement in the oxidation peak current of CP on PtNPs/GNS-CNS/GCE...
Effect of electrolyte concentration on microstructure and properties of micro arc oxidized hydroxyapatite/titania nanostructured composite
, Article Materials Science and Engineering C ; Volume 33, Issue 5 , 2013 , Pages 2555-2561 ; 09284931 (ISSN) ; Golestani Fard, F ; Mirhosseini, S. M. M ; Ziaee, A ; Mehrjoo, M ; Sharif University of Technology
2013
Abstract
Micro arc oxidation was employed to grow TiO2/hydroxyapatite composite layer on titanium substrate. The correlation between electrolyte concentration, diameter and density of the pores in fabricated layers was investigated. Therefore, the effect of electrolyte concentration on composition and morphology of grown layers was studied using SEM, EDX, XRD and XPS techniques. Samples were coated in electrolytes containing 5, 10 and 15 g/l calcium acetate and 1, 3 and 5 g/l β-glycerophosphate, at optimized voltage for 3 min. Pore size variations obey a similar pattern by the addition of both calcium acetate and β-glycerophosphatein various concentrations based on SEM observations. However,...
Effect of high energy ball milling on compressibility of nanostructured composite powder
, Article Powder Metallurgy ; Volume 54, Issue 1 , Nov , 2011 , Pages 24-29 ; 00325899 (ISSN) ; Farnoush, H. R ; Asgharzadeh, H ; Sadrnezhaad, S. K ; Sharif University of Technology
2011
Abstract
Compressibility of a nanostructured Al-5AlN composite powder synthesised via high energy ball milling for various times was studied by means of a modified Heckel equation. Since workhardening and morphological changes take place by milling evolution, the compressibility was consequently affected. Strengthening of composite compacts was influenced by milling and compaction processes, i.e. strength of compacts increased at longer milling times and higher compaction pressures. It was found that, at the initial stages of milling and higher compaction pressures, the strengthening was mostly affected from compaction process, whereas the milling strengthening fraction was near to unity at lower...
Mesoporous nanostructured composite derived from thermal treatment CoFe prussian blue analogue cages and electrodeposited NiCo-S as an efficient electrocatalyst for an oxygen evolution reaction
, Article ACS Applied Materials and Interfaces ; Volume 12, Issue 14 , 2020 , Pages 16250-16263 ; Shahrokhian, S ; Sharif University of Technology
American Chemical Society
2020
Abstract
Developing effective and priceless electrocatalysts is an indispensable requirement for advancing the efficiency of water splitting to get clean and sustainable fuels. Herein, we reported a feasible strategy for preparing a trimetallic (NiCoFe) superior electrocatalyst with a novel open-cage/3D frame-like structure for an oxygen evolution reaction (OER). It is prepared by consequent thermal treatments of a CoFe Prussian blue analogue frame/cage-like structure under an argon (CoFeA-TT) atmosphere and then electrochemical deposition of nickel-cobalt sulfide nanosheets as a shell layer on it. The electrochemical measurements demonstrated that the deposition of NiCo-S on CoFeA-TT...
Facile synthesis of N-doped hollow carbon nanospheres wrapped with transition metal oxides nanostructures as non-precious catalysts for the electro-oxidation of hydrazine
, Article Journal of Electroanalytical Chemistry ; Volume 873 , 2020 ; Rezaee, S ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In the present work, N-doped hollow carbon nanospheres (N-HCNSs) is prepared by direct carbonization of polyaniline-co-polypyrrole (PACP) hollow spheres without template needing. Two different NiO nanostructures (nanosheets and nanowires) are prepared by forming a shell around the N-HCNSs via simple hydrothermal/calcination processes (NiO-NSs@N-HCNSs and NiO-NWs@N-HCNSs). The morphology and structure of the nanostructures are characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The prepared nanocomposites are used as catalysts for the electrocatalytic...