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thermal-decomposition
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Superabsorbent polymer as nanoreactors for preparation of hematite nanoparticles and application of the prepared nanocatalyst for the friedel-crafts acylation
, Article Journal of the Brazilian Chemical Society ; Volume 20, Issue 3 , 2009 , Pages 466-471 ; 01035053 (ISSN) ; Moghaddam, F. M ; Pourjavadi, A ; Barzegar, S ; Soleyman, R ; Sohrabi, A ; Sharif University of Technology
2009
Abstract
The synthesis of pure α-Fe2O3 nanoparticles (30 nm) using a superabsorbent nanopolymer (SANP) by the thermal decomposition is reported. Synthesized α-Fe2O3 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electronic microscopy (TEM) and thermogravimetric analysis (TG) techniques. The applicability of this nanostructure material was assessed by its catalytic effect on the Friedel-Crafts acylation. ©2009 Sociedade Brasileira de Química
Gas-phase kinetics and mechanism of diallyl sulfide thermal decomposition
, Article Journal of Physical Organic Chemistry ; Volume 16, Issue 3 , 2003 , Pages 153-157 ; 08943230 (ISSN) ; Izadyar, M ; Sharif University of Technology
2003
Abstract
The gas-phase kinetics of diallyl sulfide pyrolysis were studied experimentally and theoretically in a static system over the temperature range 433-463 K and a total pressure of 80 Torr in a glass vessel with the free radical inhibitor cyclohexene. The experimental results show that this reaction is homogeneous, unimolecular and follows a first-order rate law. Theoretical studies at the B3LYP/6-31G* computational level indicate that the elimination reaction proceeds through a six-centered cyclic transition state and the reaction mechanism is concerted and non-synchronous. Copyright © 2003 John Wiley & Sons, Ltd
Effect of CO2 partial pressure on the thermal decomposition kinetics of zinc carbonate hydroxide
,
Article
International Journal of Engineering, Transactions B: Applications
;
Volume 24, Issue 3
,
2011
,
Pages 263-268
;
1728-144X (ISSN)
; Halali, M
; Nobari, A. H
;
Sharif University of Technology
Abstract
In this work, the effect of carbon dioxide partial pressure on the calcination kinetics of high purity zinc carbonate hydroxide has been studied. Non-isothermal analysis has been performed on samples at different CO 2 partial pressures by TGA and DTA. It has been found that the calcination behaviour of this material corresponds to the shrinking core model and the reaction mechanism is phase boundary controlled. The calcination reaction of zinc carbonate hydroxide starts at 240 °C. Increasing the carbon dioxide partial pressure can result in an increase in the reaction start temperature of up to 30°C. The activation energy for the reaction is calculated as 180 ± 5 kJ/mol at...
Smulation of Hydrogen Production by the Process of Thermal Decomposition of Methane
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
Different disadvantages associated with using fossil fuels as the main energy source including crisis of wells’ depletion and serious environmental problems, causing by the emission of large quantities of greenhouse gases (GHG), especially carbon dioxide (CO2), has increased attention to replacing them with renewable and clean fuels such as wind, solar, and geothermal energy sources. Hydrogen, as a clean energy carrier, is one of the best fuels in terms of the environment and cost. So, it is recently receiving increasing attention and it may one day replace fossil fuels for various applications such as in automobiles and power stations. The main subject of this thesis was surveying the...
Production of SnO2 nano-particles by hydrogel thermal decomposition method
, Article Materials Letters ; Volume 65, Issue 9 , 2011 , Pages 1249-1251 ; 0167577X (ISSN) ; Barzegar, S ; Ebrahimi, G. R ; Varahram, N ; Sharif University of Technology
Abstract
SnO2 is an important functional material having a wide range of applications in gas sensors and optoelectronic devices. There is a great interest for finding new cost-effective and straight-forward methods for production of these particles. In this research, hydrogel thermal decomposition method (HTDM) is used for production of high purity SnO2 nano-particles. Cost effective reactants and green routs of production are the advantages of polysaccharide based hydrogel as starting material for this method. Visual observations indicated that there is very little tendency for agglomeration in the SnO2 nano-particles produced by this method which can be considered as an advantage for this method...
Synthesis of titanium oxide nanotubes and their decoration by MnO nanoparticles for biomedical applications
, Article Ceramics International ; Volume 45, Issue 15 , 2019 , Pages 19275-19282 ; 02728842 (ISSN) ; Mahmoudi, P ; Zamanian, A ; Mozafari, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this study, apatite formation ability on TiO2 nanotubes (TNTs) synthesized by anodizing process were compared with TNTs decorated by MnO nanoparticles. The MnO nanoparticles used for decoration process were fabricated via thermal decomposition method. At first, it was strived to find the optimal condition of anodizing process and the effect of applied voltages (15 V, 20 V, and 25 V) and process times (15 min, 20 min, and 25 min) on the diameter of the synthesized TNTs was investigated. Results of microscopic characterizations showed that the completely uniform structure of nanotubes with a diameter in the range of about 100–130 nm was achieved after 20 min of anodizing process at an...
Electrochemical Behaviors of RuO2-TiO2 Mixed Metal Oxide Coated on Titanium Anodes in Chlor-Alkali Electrolysis
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titanium anodes activated by noble metal oxides under the trade name of dimensionally stable anodes (DSAs) are widely used in the electrolytic industry, particularly in chlor – alkali electrolysis. Over 20 years of use, the fundamental aspects of their long – lasting performance are not fully understand and the corrosion mechanisms are still the subject of many investigations. RuO2 – TiO2 coatings on titanium substrate, due to proper electrochemical characteristics and good corrosion resistance, is most applicable as an anode in chlor – alkali systems. In the present investigation, the first layer of Pt – Ir coating is applied via electrodeposition method on the pretreated titanium substrate...
Conversion of Waste Personal Protective Equipment Against Corona Into Valuable Fuel Products by Thermal Decomposition Method
, M.Sc. Thesis Sharif University of Technology ; Fotovat, Farzam (Supervisor)
Abstract
The COVID-19 pandemic has increased environmental risks due to widespread face mask use in production, consumption, and disposal. This study uses surgical single-use as a pyrolysis feedstock due to increased demand. This study investigates the conversion of valuable materials from waste through the recycling of surgical single-use masks in a fluidized bed. The first stage of this study focused on identifying and specifying the main components in the filter layers of disposable surgical masks, which were the compounds in the filter layers made of polypropylene. TGA curves investigated thermal behavior of disposable surgical mask layers, revealing pyrolysis feedstock can produce volatile...
Influence of fine structure on the variations of thermal and mechanical properties in flax fibers modified with different alkaline treatment conditions
, Article Journal of Natural Fibers ; 2021 ; 15440478 (ISSN) ; Bagheri, R ; Dai, C ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
The alkaline treatment condition plays a crucial role in governing the ultimate properties of flax fibers. In this study, flax fibers were modified with mild alkalization and severe mercerization conditions to give fundamental insight into how the molecular-scale changes in cell wall fine structure and cellulose supramolecular structure can affect the macroscopic properties of fibers. SEM, FTIR, XRD, TGA, and DSC techniques were employed to characterize the variations in morphology, composition, crystalline structure, and thermal properties of fibers. Also, tensile tests evaluated their reinforcing performance in polypropylene-based composites. The results indicated that alkalization in 5%...
Thermal decomposition of nanostructured Aluminum Titanate in an active Al matrix: A novel approach to fabrication of in situ Al/Al2O3-Al3Ti composites
, Article Materials and Design ; Volume 88 , 2015 , Pages 932-941 ; 02641275 (ISSN) ; Hosseini, H. R. M ; Jafari, M ; Bagheri, N ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
The thermal decomposition of Aluminum Titanate in exposure to pure Aluminum was examined both in powder and in bulk form. Optical microscopy, FE-SEM, XRD, DSC and TGA examinations were conducted to take the possible chemical reactions between Aluminum Titanate and Al into consideration. It was found that as Aluminum Titanate particles are exposed to Al matrix, the thermal stability of Aluminum Titanate is degraded and its decomposition temperature is reduced from 850°C to 550°C. Also, the chemical reactions between Aluminum Titanate and Al start along the interfaces, and the reaction products, i.e. Al3Ti, Al2O3, TiO2 and O2 gas are left there. A mechanism was suggested to describe the...
Photocatalytic activity of CuO nanoparticles incorporated in mesoporous structure prepared from bis(2-aminonicotinato) copper(II) microflakes
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 25, Issue 11 , November , 2015 , Pages 3634-3642 ; 10036326 (ISSN) ; Akhavan, O ; Bijanzad, K ; Sharif University of Technology
Nonferrous Metals Society of China
2015
Abstract
An easy method for preparing CuO nanoparticles incorporated in a mesoporous structure was presented based on the thermal decomposition of a copper complex. The novel copper coordination compound of [Cu(anic)2]·0.75H2O (anic= 2-aminonicotinate) with the microflake morphology was synthesized through the reaction of 2-aminonicotinic acid (Hanic) and copper(II) nitrate. Using elemental analysis and Fourier transform infrared (FTIR) spectroscopy, the chemical composition of CuC12H11.5N4O4.75 was proposed. Calcination process at 550 °C for 4 h transformed the microflakes into CuO nanoparticles incorporated in a mesoporous structure. The FTIR peaks assigned to 2-aminonicotinate were completely...
A new method for fabrication of in situ Al/Al3 Ti-Al2 O3 nanocomposites based on thermal decomposition of nanostructured tialite
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Article
Journal of Alloys and Compounds
;
Volume 643
,
2015
,
Pages 64-73
;
09258388 (ISSN)
; Madaah Hosseini, H.R
;
Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this research, the possibility that nanostructured aluminium titanate (tialite) powder can be used as a chemical source for producing Al2 O3 and Al3 Ti precipitates in aluminium matrix composites has been investigated. Optical microscopy, FE-SEM, XRD, DSC and TGA examinations were used to characterize the synthesized specimens. The results showed that a porous structure and inferior mechanical properties were obtained in as-sintered samples. The further thermomechanical treatments i.e. cyclic rolling and hot extrusion improved the mechanical properties and led to a dense microstructure with a homogeneous distribution of Al2 O3 and...
Investigation of Thermomechanical Properties of UHMWPE/Graphene Oxide Nanocomposites Prepared by in situ Ziegler-Natta Polymerization
, Article Advances in Polymer Technology ; Volume 34, Issue 4 , February , 2015 ; 07306679 (ISSN) ; Ramazani, A.S.A ; Kheradmand, A ; Shafiee, M ; Baniasadi, H ; Sharif University of Technology
John Wiley and Sons Inc
2015
Abstract
The graphene-based Ziegler-Natta catalyst has been used to prepare ultrahigh molecular weight polyethylene/graphene oxide (UHMWPE/GO) nanocomposite via in situ polymerization. The morphological investigations have been conducted using X-ray diffraction patterns and scanning electron microscopy method. The obtained results indicated that no diffraction peak is detected in a GO pattern, which could be due to the exfoliation of graphene nanosheets in the UHMWPE matrix. Morphological investigations indicated that GO nanosheets are dispersed almost uniformly in polymeric matrix, and that there should exist a good interaction between nanofillers and matrix. The mechanical properties of the...
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....
Modified chitosan as a polymeric nanoreactor for fabrication of pure zno nano particles
, Article Journal of Applied Polymer Science ; Volume 117, Issue 2 , March , 2010 , Pages 1035-1040 ; 00218995 (ISSN) ; Barzegar, S ; Pourjavadi, A ; Sharif University of Technology
2010
Abstract
ZnO nanoparticles have been prepared successfully by hydrogel decomposition method (HDM). Synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD), fourier transforms infrared spectroscopy (FTIR), and transition electron microscopy (TEM) techniques. Narrow distribution of sizes with a 20-30 nm diameter and regular distribution of ZnO nanoparticles are attributed to the application of poly(acrylic acid-co-acrylamide) grafted chitosan hydrogel as coating agent. The results show that the polymer thermal decomposition technique is a perfect method for the synthesis of ZnO nano particles
Numerical simulation of nano-carbon deposition in the thermal decomposition of methane
, Article International Journal of Hydrogen Energy ; Volume 33, Issue 23 , December , 2008 , Pages 7027-7038 ; 03603199 (ISSN) ; Saboohi, Y ; Firoozabadi, B ; Sharif University of Technology
2008
Abstract
A comparison of various hydrogen production processes indicates that the thermal decomposition of methane (TDM) provides an attractive option from both economical and technical points of view. The main problem for this process is the deposition of the nano-carbon particles on the reactor wall (or catalyst surface). This research concentrates on the numerical simulation of the TDM process without use of a catalyst to find a technique that decreases the carbon accumulation in a tubular reactor. In this model, the produced carbon particles are tracked with the Lagrangian method under thermophoretic, Brownian, van der Waals, Basset, drag, lift, gravity, pressure and virtual mass forces. In...
Thermal stability and strain sensitivity of nanostructured aluminum titanate (Al2TiO5)
, Article Materials Chemistry and Physics ; Volume 223 , 2019 , Pages 202-208 ; 02540584 (ISSN) ; Azarniya, A ; Madaah Hosseini, H. R ; Abedi, M ; Moskovskikh, D ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In the present work, nanostructured aluminum titanate (Al2TiO5 or AT) was synthesized by the sol-gel method and potential effects of mechanical strain on its phase analysis, morphology, and thermal stability were investigated in some details for the first time, because the thermal instability of AT is beneficial to the fabrication of in-situ aluminum matrix composites. To characterize the particle distribution, microstructure and thermal durability of AT after the strain induction, field-emission scanning electron microscope (FE-SEM), differential scanning calorimetry (DSC), and x-ray diffraction analysis (XRD) were utilized. The experimental results showed that a 3-h ball milling process...