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Ghazijahani T.G.,Islamic Azad University at Mahabad | Showkati H.,Urmia University
Journal of Constructional Steel Research | Year: 2011

In previous studies, a proliferation of research work has been undertaken on the buckling behavior of shell structures particularly conical shells. Nonetheless, no experimental studies are found in the literature on the buckling of a full and real configured model of a slender shell reducer with two cylindrical end boundaries. To this end, buckling behavior of three conical shell reducers under uniform peripheral pressure was investigated and evaluated experimentally in this paper. In addition, relevant FE simulations as well as theoretical predictions were taken into account to compare buckling load and modes of deformation. Derived results were aimed at generalizing the data for conical reducers in full scale within the range of this study. © 2011 Elsevier Ltd. All rights reserved. Source


Jaberian H.,University of Tehran | Piri K.,Bu - Ali Sina University | Nazari J.,Islamic Azad University at Mahabad
Food Chemistry | Year: 2013

Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC-MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50 μg). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic-water extracts were 1119 and 1966 mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity. © 2012 Elsevier Ltd. All rights reserved. Source


Sharafi H.,Islamic Azad University at Mahabad | Rahimi R.,University of Kurdistan
Journal of Strength and Conditioning Research | Year: 2012

2012-Apoptosis is a programmed cell death that has been demonstrated in human and animal studies and plays an essential role to remove injured cells after acute strenuous exercise. Protein p53 plays important roles in regulating apoptosis via mitochondrial pathway. Therefore, the aims of this study were to determine the effects of acute resistance exercise (RE) on serum p53, caspase-9, and caspase-3, markers of apoptosis, and whether resistance training status influences the magnitude of the RE-induced apoptosis. Nine resistance-trained (RT) (age, 22.37 ± 1.99 years; height, 174 ± 5.04 cm; body weight, 71.32 ± 5.57 kg; and body mass index [BMI] 23.58 ± 2.05 kg·m -2) and 9 untrained (UT) college-age men (age, 22.25 ± 2.13 years; height, 171 ± 3.4 cm; body weight, 68.45 ± 3.23 kg; and BMI, 23.41 ± 1.08 kg·m -2) volunteered to participate in this study. Resistance-trained and UT men completed an RE bout consisting of 4 sets of 6 exercise at 80% of 1 repetition maximum until failure. Serum levels of p53, caspase-9, and caspase-3 were examined at preexercise (pre), immediately post (IP), 3 hours post (3 hours post), and 24 hours post RE (24 hours post). In UT, serum levels of p53, caspase-9, and caspase-3 were significantly increased at IP compared with RT. However, plasma insulin-like growth factor 1 level was higher for RT compared with UT at IP. Collectively, our data suggest the role of p53 in regulating apoptosis through mitochondrial pathway as measured by caspase-9 and caspase-3 after acute RE in UT. Our results also revealed that regular RT alters apoptosis biomarkers, especially the intrinsic pathway of apoptosis. © 2012 National Strength and Conditioning Association. Source


Ghanbari Ghazijahani T.,Islamic Azad University at Mahabad | Showkati H.,Urmia University
Journal of Constructional Steel Research | Year: 2013

Thin-walled cylindrical shells are extensively used in numerous kinds of industrial applications under different cases of load combination. Nonetheless, quite few are the experimental researches that point out the real behavior of cylindrical shells under pure bending and external pressure. In the present experimental study, the buckling behavior of long cylindrical steel shells was investigated under combined bending and uniform peripheral pressure. Relevant FE simulations were also carried out and the results were compared with the experiments. The study shows that the theoretical outcomes predicted by nonlinear finite element analyses agree acceptably with the experimental results in terms of bucking load and modes of deformation. Furthermore, it was found that the initial sectional out of circularity developed by bending (especially higher values) considerably influences the buckling capacity of such shells under uniform external pressure. Ultimately, an interaction formula was proposed to generalize the interaction behavior of the test results within the range of this study. © 2013 Elsevier Ltd. Source


Kakemam J.,Islamic Azad University at Mahabad | Peyghan A.A.,Islamic Azad University at Tehran
Computational Materials Science | Year: 2013

We have performed density functional theory calculations to investigate the influence of doping of C and Si atoms on the geometric, electronic, solvation, energetic, and field emission properties of a MgO nano-cage. It has been found that substitution of one of the Mg atoms of the nano-cage by either C or Si atom is energetically favorable while substituting an O atom with both of them is unfavorable. It has been also found that replacing Mg or O atom of the cluster by one C atom much more increases its conductance than that by Si one. In fact, HOMO/LUMO gap (Eg) of the cluster is reduced from 4.86 to 1.11 eV, upon replacing Mg atom by C. Based on the obtained results, substituting a Mg atom by either C or Si atom may significantly increase the field electron emission current from the cluster surface by reducing its work function. Overall, doping of Mg12O12 nano-cage by either C or Si atom increases its solubility, conductance, electric dipole moment, kinetic stability, and field electron emission while decreases the Eg and work function. © 2013 Elsevier B.V. All rights reserved. Source

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