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Mirmehdi S.M.,Gorgan University of Agricultural Sciences and Natural Resources | Zeinaly F.,Islamic Azad University at Gorgan | Dabbagh F.,Gorgan University of Agricultural Sciences and Natural Resources
Composites Part B: Engineering | Year: 2014

The effect of the filler content and the different type of wood flour on the mechanical properties of polyethylene composites filled with an agricultural pruning residue, date palm wood flour (DPWF) was studied. The different types of DPWF were rachis, leaflet and leaf, resulting from that annual pruning of date palm tree. Composites were made at 45%, 60% and 75% by weight wood flour contents. The particle size was 25-40 mesh and Maleic Anhydride modified polyethylene was also added at 2% of total weight of each board. First, the palletized feedstock from DPWF and plastic were provided by a twin screw extruder and then, the compound pellets ground and the final boards were made of them by a hot-press. It was observed that by increasing the filler content, the mechanical properties, flexural strength (MOR) and tensile strength decreased, while the flexural modulus (MOE) increased. The tensile strength did not show significant differences as a function of the filler type while the flexural strength and the flexural modulus of the boards made from leaflet flour, was the highest. © 2013 Published by Elsevier Ltd.

Soltani A.,Islamic Azad University at Gorgan | Ahmadian N.,Islamic Azad University at Qaemshahr | Kanani Y.,Islamic Azad University at Gorgan | Dehnokhalaji A.,Golestan University | Mighani H.,Golestan University
Applied Surface Science | Year: 2012

The thiocyanate anion (SCN -) adsorption capacity of zigzag single-walled boron nitride nanotubes (SWBNNTs) is studied via first-principles theory. Binding energy corresponding to the most stable configuration of SCN -/BNNT is found to be -148.42 kJ mol -1, which is typical for the chemisorptions. Our results indicate that both aluminum and gallium doping can significantly enhance the adsorption energy of SCN -/BNNTs complexes. Our electronic results reveal that there is a significant orbital hybridization between two species in adsorption process being an evidence of strong interaction. Thus, we arrive at the prediction that the BNNTs nanocage can be implemented as suitable sensor for practical applications.

Peyghan A.A.,Islamic Azad University at Tehran | Soltani A.,Islamic Azad University at Gorgan | Pahlevani A.A.,Islamic Azad University at Gorgan | Kanani Y.,Islamic Azad University at Gorgan | Khajeh S.,Payame Noor University
Applied Surface Science | Year: 2013

First-principles computations have been applied to scrutinize the adsorption behavior of CO molecule on the external surface of H-capped aluminum- and gallium-doped (6, 0), (8, 0) zigzag and (5, 5) armchair single-walled BN nanotubes (SWBNNTs). Binding energy corresponding to the most stable configuration of CO on the gallium-doped (6, 0) BNNT is found to be -0.83 eV, which is high typical sensitivity to CO molecule. Our results indicate that both Al- and Ga-doping can notably enhance the adsorption energy of CO/BNNTs complexes. Our electronic results reveal that there is a notable orbital hybridization among two species in adsorption process being an evidence of strong interaction. For the CO/BNNTs complexes, the energy gaps, NBO, dipole moments, natural atomic orbital occupancies and global indices are computed. Finally, we reported a novel type of toxic gas sensor that can be used for detecting the presence of CO molecule. © 2012 Elsevier B.V.

Soltani A.,Islamic Azad University at Gorgan | Peyghan A.A.,Islamic Azad University at Tehran | Bagheri Z.,Islamic Azad University at Tehran
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2013

We have performed a comparative density functional theory study on adsorption of hydrogen peroxide (H2O2) on the boron nitride and silicon carbide nanotubes (BNNT and SiCNT) in terms of energetic, geometric, and electronic properties. It has been found that the molecule is chemically adsorbed on both of the tubes so that its interaction with SiCNT (adsorption energy ∼-0.97 eV) is much stronger than that with BNNT (adsorption energy ∼-0.47 eV). The H2O2 adsorption on BNNT slightly decreases its work function, increasing the field electron emission from the BNNT surface while it may not affect that of the SiCNT. In addition, the adsorption process may increase the electrical conductivity of SiCNT while does not affect that of the BNNT, significantly. We believe that the SiCNT may be a potential candidate for detection of H2O2. © 2013 Elsevier B.V. All rights reserved.

Baei M.T.,Islamic Azad University | Kanani Y.,Islamic Azad University at Gorgan | Rezaei V.J.,Islamic Azad University at Gorgan | Soltani A.,Islamic Azad University at Gorgan
Applied Surface Science | Year: 2014

The sensitivity of Ga-doped BN nanotubes to prevalent gas molecules (H 2S, HS-, H2O2, and H2CO) has been studied using B3LYP density functional theory (DFT) method. The chemisorption of H2S, HS-, H2O2, and H2CO molecules on (8, 0) BN nanotubes are estimated to be -1.61, -4.05, -1.27, and -1.28 eV, respectively. The obtained results of binding energies imply that the Ga-doped (8, 0) BN nanotubes can be a promising candidate for modification of sensor materials for the detection of H 2S, HS-, and H2CO molecules compared with the Ga-doped (5, 5) BN nanotubes. Also, these results represent that the Ga-doped (8, 0) BN nanotubes have high recovery time and high sensitivity to the presence of H2S, HS-, and H2CO molecules. © 2014 Elsevier B.V. All rights reserved.

Mahmoudian M.R.,University of Malaya | Mahmoudian M.R.,Islamic Azad University | Alias Y.,University of Malaya | Basirun W.J.,University of Malaya | And 2 more authors.
Electrochimica Acta | Year: 2012

This study examines the preparation of ultra-thin polypyrrole nanosheets decorated with Ag nanoparticles (Ag-UTPNSs) and their application in the enzyme-less detection of hydrogen peroxide (H 2O 2) detection. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results confirmed that Ag nanoparticles (NPs) were deposited onto the surface of the UTPNSs. The increase of the H 2O 2 reduction current peak to 120 μA in the presence of the Ag-UTPNS/glassy carbon electrode (GCE) as compared to the UTPNS/GCE indicates that the sensitivity of the electrode to H 2O 2 is significant. This observation can be explained by the larger surface area of the UTPNSs, which can increase the interactions between the polymer and the AgNO 3 solution during the deposition of the Ag NPs, and by the small size of the deposited Ag NPs, which can produce a surface area of Ag that is suitable for the reaction with H 2O 2. The amperometric responses show that the limit of detection, the limit of quantification (S/N = 3) and the sensitivity are estimated to be 0.57 μM, 1.93 μM and 4.477 μA mM -1, respectively, for the linear segment. The results of the reproducibility experiments show that the use of Ag-UTPNS/GCE is feasible for the quantitative detection of certain concentration ranges of H 2O 2. © 2012 Elsevier Ltd.

Golsefidi M.A.,Payame Noor University | Golsefidi M.A.,Islamic Azad University at Gorgan | Es'haghi Z.,Payame Noor University | Sarafraz-Yazdi A.,Ferdowsi University of Mashhad
Journal of Chromatography A | Year: 2012

In this study, a simple preparation approach was developed for modified bisphenol A (BPA) molecularly imprinted polymer sorbent used in the hollow fiber solid phase microextraction (MIP-HF-SPME) of chlorogenic acid (CGA). The pre-polymer solution containing the template was introduced into the polypropylene hollow fiber segment for in situ polymerization. MIP-HF-SPME conditions based on the modified MIP-sorbent were optimized. Finally, the tool was used for selective extraction of chlorogenic acid in Echinacea purpurea, a medicinal plant. Main parameters affecting synthesis of organic-inorganic hybrid MIP and microextraction procedure were investigated and optimized. The measurements were done under the optimal conditions. The limit of detection has been gained 0.08. ng/mL. The linear range and relative standard deviation (RSD %) are 0.2-1000. ng/mL and 0.38 (n= 3) respectively. The average relative recoveries of spiked analyte in the four concentration levels were between 84.8 and 97.2%. © 2012 Elsevier B.V.

Tazikeh-Lemeski E.,Islamic Azad University at Gorgan
Journal of Theoretical and Computational Chemistry | Year: 2016

In this study, we estimated the optimum concentration of copper ions that are effective in the stability and the structural changes of human growth hormone (hGH) protein in the combination of different concentrations of these ions at the molecular level using molecular dynamics simulation by Gromacs 4.6.5 software. Moreover, to estimate the binding affinity of copper ions to hGH protein, binding free energies is calculated by the molecular mechanics Poisson–Boltzmann Surface Area (MM-PBSA). The analysis of molecular dynamics (MD) trajectories as dictionary of the secondary structure of protein (DSSP), solvent accessible surface area (SASA) and binding free energy calculations show that hGH protein structure is more stabilized by increasing a limited concentration of copper ions. These findings align with our previous experimental studies. © 2016 World Scientific Publishing Company

In the present work, nanoporous alumina microspheres have been synthesized by sol-gel technique. Acid deficient aluminum nitrate and a mixture of equimolar HMTA-Urea were used as starting materials. The prepared sol then injected as droplets into hot oil column to give spherical shape. After calcinations the samples were characterized by scanning electron microscope, fourier transform infra-red spectroscopy, thermogravimetry-differential thermal analysis, X-ray diffraction and N2 adsorption-desorption isotherms. With respect to the results achieved from the above analyses, it was found that nanoporous alumina microspheres with controllable size and morphology can successfully be produced through sol-gel method. © 2013 Springer Science+Business Media New York.

Moradi A.V.,Islamic Azad University at Gorgan
Chemistry of Heterocyclic Compounds | Year: 2015

(Forumula presented) The N-(1,3-oxathiol-2-ylidene)carboxamides have been synthesized in excellent yield in the reaction between alkyl bromide, acid chloride, and ammonium thiocyanate in the presence of catalytic amount of ZnO nanosheets (15 mol %) in water as a solvent at room temperature. The separation of product from the reaction mixture is very simple. Using NS-ZnO as a catalyst considerably improves the yield of the desired product in comparison with performing these reactions without catalyst. The catalyst shows good reusability. © 2015 Springer Science+Business Media New York.

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