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Sinapour H.,Maleke ashtar University of Technology | Damiri S.,Maleke ashtar University of Technology | Pouretedal H.R.,Maleke ashtar University of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2017

The thermal decomposition kinetic behavior of three HMX explosive samples containing 5.0 mass% (A-HMX) and 0.5 mass% RDX impurity (B-HMX) and HMX desensitized with 5.0 mass% paraffin wax (W-HMX) was studied by non-isothermal differential scanning calorimetric and thermogravimetric techniques at different temperature scan rates and by isothermal accelerated aging method. Using KAS isoconversional method, the mean activation energies of 229.36, 221.05, and 267.37 kJ mol−1 were obtained for B-HMX, A-HMX, and W-HMX, respectively, showing the higher thermal stability of pure and desensitized HMX. Moreover, the reaction mechanism was found in Avrami–Erofeev A2 model for all samples. In this study, by using the calculated kinetics triplets, the chemical lifetime of explosives were predicted based on 5.0 mass% mass loss and were compared with isothermal accelerated aging results, under two constant temperatures. The experimental results in the higher temperatures demonstrated relatively better consistency with predicted values. © 2017 Akadémiai Kiadó, Budapest, Hungary

Damiri S.,Maleke ashtar University of Technology | Oskoei Y.M.,Urmia University of Technology | Fouladgar M.,Islamic Azad University at Falavarjan
Journal of Experimental Nanoscience | Year: 2016

This paper describes the development of 1-methyl-3-butylimidazolium chloride ionic liquid/cobalt hexacyanoferrate nanoparticle modified multi-walled carbon nanotubes nanocomposite paste electrode for the electrocatalytic and adsorptive stripping voltammetric and impedimetric determination of diclofenac (DIC) in real samples. The nanocomposite was prepared by a simple chemical method and was characterised by scanning electron microscopy, Fourier transform infrared spectroscopy and atomic absorption spectroscopy. Also, the electrochemical behaviours of the modified electrode and the electrocatalytic oxidation of DIC were investigated in detail by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques. The kinetic parameters such as electron transfer coefficient, and apparent rate constant for the redox reaction between DIC and the modified electrode were also determined using electrochemical approaches. It was found that the modified electrode exhibited excellent electrocatalytic activity toward the oxidation of DIC, and under the optimised conditions, the linear response range and detection limit were found to be 1.0–100.0 and 0.3 μM, respectively using the differential pulse voltammetry method. The proposed method was applied for the sensitive and selective determination of diclofenac in the urine samples and pharmaceutical formulations with satisfactory results. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Ranjbar A.,Tohoku University | Babamoradi M.,Sharif University of Technology | Heidari Saani M.,Maleke Ashtar University of Technology | Vesaghi M.A.,Sharif University of Technology | And 2 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Using a generalized Hubbard Hamiltonian, many-electron calculations of energy levels and corresponding wave functions of negatively charged and neutral nitrogen-vacancy centers in diamond were reported. The energies, orbital, and spin symmetries of the ground and excited states are in good quantitative agreement with available optical and electron paramagnetic resonance measurements. The many-electron wave functions were employed to predict the spin density on the N and C atoms in the ground and excited states. The present model explains the recent, experimentally observed definite nonzero spin density on N atom for the 4A2 excited state of the neutral charge state of NV (NV0) based on the multiple electronic configuration of the corresponding many-electron wave function. © 2011 American Physical Society.

Hajizadeh-Oghaz M.,Maleke Ashtar University of Technology | Razavi R.S.,Maleke Ashtar University of Technology | Estarki M.L.,Isfahan University of Technology
Bulletin of Materials Science | Year: 2014

Yttria-stabilized zirconia nanopowders were synthesized on a relatively large scale using Pechini method. In the present paper, nearly spherical yttria-stabilized zirconia nanopowders with tetragonal structure were synthesized by Pechini process from zirconium oxynitrate hexahydrate, yttrium nitrate, citric acid and ethylene glycol. The phase and structural analyses were accomplished by X-ray diffraction; morphological analysis was carried out by field emission scanning electron microscopy and transmission electron microscopy. The results revealed nearly spherical yttria-stabilized zirconia powder with tetragonal crystal structure and chemical purity of 99.1% by inductively coupled plasma optical emission spectroscopy on a large scale. © 2014 Indian Academy of Sciences.

Oghaz M.H.,Maleke Ashtar University of Technology | Razavi R.S.,Maleke Ashtar University of Technology | Estarki M.L.,Isfahan University of Technology | Ghasemi R.,Maleke Ashtar University of Technology
Journal of Nano Research | Year: 2013

The morphology and particle size of yttria stabilized zirconia (YSZ) nanopowders synthesized by Pechini's method are very much dependent on the type of chelating agent, pH of solution, calcinations temperature, calcinations time, etc. In the present study, the influence of process parameters like the type of zirconium salt, pH of solution, calcinations temperature and time on the morphology and particle size of a YSZ nanopowder was analyzed by the Taguchi Design method and analysis of variance (ANOVA). According to the experimental results and ANOVA, the pH of solution and calcinations temperature are the most significant factors influencing the morphology and particle size of YSZ nanopowder; pH of solution is the most significant factor influencing the morphology; and calcinations temperature is the most significant factor affecting the particle size. Models were developed for predicting the morphology and particle size of the YSZ nanopowder. They were found to be in good agreement with the experimental results. The models were tested for experimental conditions and were found to be close to predicted values. Both morphology and particle size of YSZ nanopowders were mainly dependent on the pH of solution. © (2013) Trans Tech Publications, Switzerland.

Damiri S.,Maleke ashtar University of Technology | Pouretedal H.R.,Maleke ashtar University of Technology | Heidari A.,Maleke ashtar University of Technology
International Journal of Environmental Analytical Chemistry | Year: 2016

An electrochemical oxidation route was developed for sensitive and selective assay of nitrotriazolone (NTO) explosive in some environmental samples on a multi-walled carbon nanotube (MWCNTs)/TiO2 nanocomposite paste electrode, for prevention of the analytical interference of conventional reducible energetic compounds. Detailed evaluations were made for the electrochemical behaviour of NTO on the modified electrode by adsorptive stripping voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques in the pH range of 2.0–10.0. Parameters such as diffusion coefficient constant of NTO were calculated, and various experimental conditions were also optimised. Under optimal conditions the calibration curve had two linear dynamic ranges of 130.0–3251.5 μg L−1 and 6.5–26.0 mg L−1 with a detection limit of 26.0 μg L−1 (0.2 μmol L−1) and precision of <3%. This electrochemical sensor was further applied to determine NTO in real soil and water samples with satisfactory results. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Pouretedal H.R.,Maleke ashtar University of Technology | Damiri S.,Maleke ashtar University of Technology | Ghaemi E.F.,Maleke ashtar University of Technology
Central European Journal of Energetic Materials | Year: 2014

The thermal behaviour of energetic materials is very important for their safe production, storage, handling and even demilitarization. In this work, the thermal behaviour and decomposition kinetics of conventional C4 plastic explosive has been studied experimentally by a non-isothermal thermogravimetric (TG)/differential thermal analysis (DTA) technique at different heating rates (2, 4, 6 and 8 °C•min-1). The kinetic triplet of activation energy, frequency factor and model of thermal decomposition of this compound has been evaluated via model-fitting and model-free methods. The results show a single thermal decomposition process for C4, with the model of integral function (g(α)) of [(1-α)-1/3 -1]2 and differential function (f(α)) of [(1-α)2/3(3α-3)/2(1-α)1/3-2], indicating a 3-dimensional diffusion mechanism. In addition, Ea values of 207.1 ± 17.3, and 241 kJ•mol-1, by using the isoconversional model-free modified Kissinger-Akahira-Sunose (KAS) and the Kissinger method, respectively, were obtained for the conversion interval of 0.3-0.7. The C4 matrix shows a significant effect on the activation energy distribution of pure RDX.

Pouretedal H.R.,Maleke ashtar University of Technology | Ebadpour R.,Maleke ashtar University of Technology
International Journal of Thermophysics | Year: 2014

The non-isothermal thermogravimetric method was used to study the thermal decomposition of KClO4, KNO3, and NaNO3 at heating rates of (5, 10, 15, and 20) K·min-1. The activation energy of thermal decomposition reactions was computed by isoconversional methods of Ozawa-Flynn-Wall, Kissinger-Akahiro-Sunose, and Friedman equations. Also, the kinetic triplet of the thermal decomposition of salts was determined by the model-fitting method of the modified Coats-Redfern equation. The activation energies of KClO4, KNO3, and NaNO3 of (293 to 307, 160 to 209, and 192 to 245) kJ·mol-1, respectively, are obtained by non-isothermal isoconversional methods. The modified Coats and Redfern method showed that the most probable mechanism functions g (α) of [-ln (1-α)]1/3 (model A3: Arami-Erofeev equation) and (1-α)- 1 -1 (model F2: second order) can be used to predict the decomposition mechanisms of KClO4, KNO 3, and NaNO3, respectively. © 2014 Springer Science+Business Media New York.

Manouchehri S.,Maleke Ashtar University of Technology | Rahimi M.,Maleke Ashtar University of Technology | Oboudiat M.,Maleke Ashtar University of Technology
Journal of Modern Optics | Year: 2016

Pattern formation is one of the many applications of diffractive optical elements (DOEs) for display. Since DOEs have lightweight and slim nature compared to other optical devices, using them as image projection device in virtual keyboards is suggested. In this paper, we present an approach to designing elements that produce distinct intensity patterns, in the far field, for two wavelengths. These two patterns are images of bilingual virtual keyboard. To achieve this with DOEs is not simple, as they are inherently wavelength specific. Our technique is based on phase periodic characteristic of wavefront using iterative algorithm to design the phase profiles. © 2015 Taylor & Francis.

Tehrani M.K.,Maleke ashtar University of Technology | Babazadeh A.,Maleke ashtar University of Technology
Asian Journal of Chemistry | Year: 2011

In this paper, we calculate the band gap of ZnS nanoparticle and show that it increases with decreasing its size. The simplest way for discussing this phenomenon and finding the band gap for different sizes is to use effective mass approximation. We show this method isn't useful for smaller sizes than 2.5 Å because the effective mass of particles below 2.5 Å also depends on the size. The density functional theory was used to obtain the band gap of ZnS nanoparticle. This theory also be used for determine the effective mass for various particle size. We find equation that shown variation effective mass for various particle sizes of ZnS. This equation fit with experimental results.

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