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Souri D.,University of Malayer
European Physical Journal B | Year: 2011

xSb 2O 3-40TeO 2-(60 - x) V 2O 5 glasses with 0 ≤ x ≤ 10 (in mol%) have been prepared by rapid- melt quenching method. DSC curves of these ternary glasses have been investigated. The glass transition properties that have been measured and reported in this paper, include the glass transition temperature (T g ), glass transition width (ΔT g ), heat capacity change at glass transition (ΔC P) and fragility (F). Thermal stability, Poisson's ratio, fragility and glass forming tendency of these glasses have been estimated, to determine relationship between chemical composition and the thermal stability or to interpret the structure of glass. In addition, Makishima and Makenzie's theory was applied for determination of Young's modulus, bulk modulus and shear modulus, indicating a strong relation between elastic properties and structure of glass. Generally, results of this work show that glass with x = 0 has the highest shear, bulk and Young's moduli which make it as suitable candidate for the manufacture of strong glass fibers in technological applications; but it should be mentioned that glass with x = 8 has higher handling temperature and super resistance against thermal attack. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Souri D.,University of Malayer
Journal of Non-Crystalline Solids | Year: 2010

The dc electrical conductivity of semiconducting oxide glasses in the (60 - x)V2O5-40TeO2-xSb2O3 system with 0 ≤ x ≤ 10,prepared by press quenching method, was studied at temperatures between 305 and 472 K. For the present glasses, the dc conductivities at 334 K were 2.67 × 10 - 6-4.35 × 10 - 5 Scm - 1, indicating that the conductivity increased with increasing V2O5 concentration. From the conductivity-temperature relation, it was found that the small polaron hopping (SPH) mechanism was applicable at the present temperatures, and the electrical conduction was due to non-adiabatic SPH of electrons between vanadium ions. For glasses with 5 ≤ x ≤ 10, the value of tunneling factor (α) was found to be 2.67 × 108 cm- 1. © 2010 Elsevier B.V.


Rezaei-Sameti M.,University of Malayer
Physica B: Condensed Matter | Year: 2012

The electrical properties and NMR parameters of the pristine and Ga-doped structures of two representative (8, 0) zigzag and (4, 4) armchair of boron phosphide nanotubes (BPNTs) have been investigated. The structural geometries of above nanotubes have been allowed to relax by optimization and then the isotropic and anisotropic chemical shielding parameters (CSI and CSA) of 11B and 31P have been calculated based on DFT theory. The results reveal that the influence of Ga-doping was more significant on the geometries of the zigzag model than the armchair one. The difference of band gap energies between the pristine and Ga-doped armchair BPNTs was larger than the zigzag model. Significant differences of NMR parameters of those nuclei directly contributed to the Ga-doping atoms have been observed. © 2012 Elsevier B.V. All rights reserved.


Rezaei-Sameti M.,University of Malayer
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2012

In this work the density functional theory (DFT) calculations are used to investigate the electrical properties of three SiC atoms doped on the representative (4, 4) armchair and (8, 0) zigzag aluminum phosphide nanotubes (AlPNTs). The mouths of nanotubes are capped by hydrogen atoms in order to saturate the dangling bonds of the boundaries and to simulate a longer tube and to decrease calculation time. The structures of all nanotubes were allowed to relax and the chemical shielding (CS) parameters were calculated for the atoms of optimized structures. The results indicated that the band gap energies and NMR parameters detect the effects of doping. The CS parameters also indicated that in both models of (4, 4) armchair and (8, 0) zigzag among all the P and Al atoms, which are directly connected to the Si and C atoms, have the smallest isotropic and anisotropic chemical shielding. © 2011 Elsevier B.V.


In this work, an armchair model of the (4,4) boron phosphide nanotubes (BPNTs) with a 1-nm length and consisting of 32 B and 32 P atoms is considered to study the influence of doping three atoms of aluminum in sites of boron (B 3AlPNTs) and three atoms of nitrogen in sites of phosphors (BP 3NNTs) on the electrostatic structure properties. The mouths of nanotubes are capped by hydrogen atoms in order to saturate the dangling bonds of the boundaries and to decrease the calculation time. The structures of BPNTs, B 3AlPNTs and BP 3NNTs are optimized by performing the level of density functional theory (DFT) using 6-31G basis set. The optimized structures are used for calculating the chemical shielding (CS) tensors and nuclear magnetic resonance parameters such as isotropic chemical shielding (CS I) and anisotropic chemical shielding (CS A). The results reveal that in both models of B 3AlPNTs and BP 3NNTs by doping N atoms the chemical shielding parameters of P and B atoms, which are directly connected to the Al and N atoms decreased and the other sites significantly changed. © 2011 Elsevier B.V. All rights reserved.


Mahdavi S.,University of Malayer
Clean Technologies and Environmental Policy | Year: 2016

Nanoparticles (NPs) modified with proper compounds are now gaining much attention for their function as new adsorbents for environmental remediation. The main objective of this study is to determine the effectiveness of modified nanoparticles (MNPs) as sorbents in removing Cd+2, Cu+2, and Ni+2 from single and competitive solutions by TiO2 NPs modified with humic acid (Ti-H), extractant of Walnut shell (Ti-W), and 1, 5 diphenyl-Carbazon (Ti-C). MNPs were characterized by XRD, FT-IR, and SEM-EDX analyzer. The MNPs were spherical in shape. The mean diameter of MNPs was determined to be 64.7 nm. The sorption of Cd+2 and Cu+2 on MNPs fitted better in Langmuir model than Freundlich model. But Ni+2 sorption better fitted in Freundlich model. Kinetics of adsorption follow pseudo-second order kinetic model than pseudo-first-order kinetic model. The adsorption maximum was observed at pH 7. Adsorption capacities of MNPs were obtained from Langmuir model and final point of isotherm. Comparison with published adsorption capacities for other adsorbents indicated that Ti-W and Ti-C had potential as proper adsorbents for the removal of Cd+2 and Cu+2 from single and competitive aqueous solution and Ti-H was a good candidate for Ni+2 removal from single and competitive solutions. © 2015 Springer-Verlag Berlin Heidelberg.


Mohebkhah A.,University of Malayer
Thin-Walled Structures | Year: 2011

Lateral-torsional buckling (LTB) strength of steel I-beams subjected to moment gradient loading is scaled by the moment gradient factor, Cb. The Cb factor depends on the non-uniformity of moment diagram, the height of the applied transverse loads within the unbraced length and end conditions. Generally, the Cb factors given by codes have been derived from elastic LTB analysis theory. However, the same Cb factors are used for beams that buckle inelastically. This paper develops a three dimensional finite element model using ANSYS for the inelastic nonlinear flexural-torsional analysis of I-beams and uses it to investigate the effects of unbraced length and central off-shear center loading (located at center, top flange and bottom flange) on the moment gradient factor in inelastic behavioral zone. It is found that the Cb factors given by AISC-LRFD in Specification for structural steel buildings (AISC 360-05) and Structural Stability Research Council Guidelines are not accurate for the point load cases applied at center and bottom flange in which I-beam buckles inelastically. It is seen also that the AISC-LRFD flexural resistance equations overestimate the actual moment capacity of inelastic I-beams under moment gradient. Therefore, a simple equation is proposed to be used instead of the code equation in inelastic zone for the investigated load cases in this paper. © 2010 Elsevier Ltd. All rights reserved.


Zinc hydroxide nitrate, an anionic exchanger layered material, undoped as well as doped with 2-10% nickel, was synthesized by using a pH-controlled precipitation method. The layered materials were then used to produce the undoped and nickel-doped zinc oxides by hydrothermal-treatment. X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy confirmed the formation of pure phase undoped and nickel-doped layered materials, as well as the products of the hydrothermal-treated materials, nanostructured zinc oxides. Optical studies of the nanostructured zinc oxides showed a decrease in band gap with increasing content of the doping agent, nickel. © 2012 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.


Souri D.,University of Malayer
Measurement: Journal of the International Measurement Confederation | Year: 2011

Ternary xMoO3-40TeO2-(60 - x)V2O 5 glasses with 0 ≤ x ≤ 60 (in mol%) have been prepared by normal melt quenching method. DSC curves of these glasses have been investigated. The glass transition properties that have been measured and reported in this paper, include the glass transition temperature (T g), glass transition width (ΔTg), heat capacity change at glass transition (ΔCP) and calculated fragility (F). Thermal stability, Poisson's ratio, fragility and glass forming tendency of these glasses have been evaluated, to determine relationship between chemical composition and the thermal stability or to interpret the structure of glass. In addition, Makishima and Makenzie's theory was applied for calculation of Young's modulus, bulk modulus and shear modulus, indicating a strong relation between elastic properties and structure of glass. Generally, results of this work show that glass with x = 60 has the highest shear, bulk and Young's moduli which make it as suitable candidate for the manufacture of strong glass fibers in technological applications; but it should be mentioned that glass with x = 20 has higher handling temperature and super resistance against thermal attack. © 2011 Published by Elsevier Ltd. All rights reserved.


Souri D.,University of Malayer
Measurement: Journal of the International Measurement Confederation | Year: 2011

Glasses with composition (60 - x)V2O5-40TeO 2 - x MoO3 with 20 ≤ x ≤ 60 (in mol%) have been prepared using the usual melt quenching method. The optical absorption spectra of the glasses have been recorded in the wavelength range 300-800 nm. The position of the absorption edge and therefore the optical band gap values were found to be depend on the glass composition. For these glasses, the optical band gap was found to be in the range 2.03-2.86 eV with increasing of MoO 3 concentration. The absorption spectrum fitting method was employed to obtain the energy gap. In this method, only the measurement of the absorbance spectrum of the glass is needed. For each sample, the width of the band tail was determined. Also, the density and glass transition temperature values indicate that the rigidity and packing of the samples increase with increase in MoO3 concentration as a network former. © 2010 Elsevier Ltd. All rights reserved.

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