Kalāleh, Iran
Kalāleh, Iran

Time filter

Source Type

Khedmati M.R.,Amirkabir University of Technology | Bayatfar A.,Azad University | Rigo P.,University of Liège
Marine Structures | Year: 2010

This paper presents the results of complementary numerical study done in the continuation of the activities carried out by the Committee III.1 " Ultimate Strength" of ISSC'2003 (Ref. [28] ).The main focus of the paper concerns the post-buckling behaviour and strength characteristics of the aluminium multi-stiffened panels under combined axial compression and lateral pressure.The finite element model proposed by the Committee III.1 " Ultimate Strength" of ISSC'2003 is used in the present investigation. Material is aluminium alloy AA6082-T6 and the multi-stiffened panel is a triple-span structure. Stiffeners are of either extruded or non-extruded angle-bar profiles. An initial deflection is imposed on the model in a procedure similar to that applied by the Committee III.1. General purpose finite element code ANSYS is used for non-linear elastic-plastic analyses.Main objectives are to study the influence of initial deflections and also HAZ on the post-buckling behaviour and collapse characteristics of aluminium stiffened panels under combined axial compression and lateral pressure. Different values of lateral pressure are exerted on the model in a systematic manner to simulate various levels of lateral pressure loading on multi-stiffened aluminium panels used in the construction of high-speed crafts. © 2009 Elsevier Ltd.

Nafisi S.,University of Tehran | Malekabady Z.M.,Azad University | Khalilzadeh M.A.,Azad University
DNA and Cell Biology | Year: 2010

β-Carboline alkaloids are present in medicinal plants such as Peganum harmala L., which have been used as folk medicine in anticancer therapy. Recently, they have drawn attention because of their antitumor activities. Despite considerable interest and investigations on alkaloid-DNA complexes, reports on alkaloid-RNA interaction are very limited. This study is the first attempt to investigate the binding of β-carboline alkaloids (harmine, harmane, harmaline, harmalol, and tryptoline) with yeast RNA. The effect of alkaloid complexation on RNA aggregation and condensation was investigated in aqueous solution at physiological conditions, using constant RNA concentration (6.25mM) and various alkaloid:polynucleotide (phosphate) ratios of 1:240, 1:160, 1:80, 1:40, 1:20, 1:10, 1:5, 1:2, and 1:1. Fourier transform infrared and UV-visible spectroscopic methods were used to determine the ligand-binding modes, the binding constants, and the stability of alkaloid-RNA complexes in aqueous solution. Spectroscopic evidence showed major binding of alkaloids to RNA with overall binding constants of Kharmine-RNA=2.95×10 7 M-1, Kharmane-RNA=5.62×105 M-1, Kharmaline-RNA=7.47×105 M -1, Kharmalol-RNA=4.32×105 M -1, and Ktryptoline-RNA=3.21×105 M -1. The affinity of alkaloids-RNA binding is in the order of harmine>harmaline>harmane>harmalol>tryptoline. No biopolymer secondary structural changes were observed upon alkaloid interaction and RNA remains in the A-family structure in these complexes. Copyright 2010, Mary Ann Liebert, Inc.

Vatankhah M.,Azad University | Asadpour V.,Sadjad Institute of Higher Educations | Fazel-Rezai R.,University of North Dakota
Applied Soft Computing Journal | Year: 2013

Diagnosing pain mechanisms is one of the main approaches to improve clinical treatments. Especially, the detection of existence and/or level of pain can be vital when verbal information is not present for instant for neonates, disabled persons, anesthetized patients and also animals. Various researches have been performed to locate and classify pain, however, no consistent result has been achieved. The aim of this study is to show a strict relation between electroencephalogram (EEG) signal features and perceptual pain levels and to clarify the relation of classified signal to pain origin. Cortical regions on scalp were assigned based on an evolutional method for optimized alignment of electrodes that improve the clinical monitoring results. The EEG signals were recorded during relax condition and variety of pain conditions. Specific spectral features which are studied to show consistency with dynamical characteristic of EEG signals were combined with non-linear features including approximate entropy and Lyapunov exponent to provide the feature vector. Evolutionary optimization method was used to reduce the features space dimension and computational costs. A hybrid adaptive network fuzzy inference system (ANFIS) and support vector machine (SVM) scheme was used for classification of pain levels. ANFIS optimizer is used to fine tune the non-linear alignment of kernels of SVM. The results show that pain levels can be differentiated with high accuracy and robustness even for few recording electrodes. This research verifies the hypothesis that electrical variations of brain patterns can be used for determination of pain levels. The proposed classification method provided up to 95% accuracy. © 2012 Elsevier B.V. All rights reserved.

Shafiei S.,Azad University | Salim R.A.,Curtin University Australia
Energy Policy | Year: 2014

This paper attempts to explore the determinants of CO2 emissions using the STIRPAT model and data from 1980 to 2011 for OECD countries. The empirical results show that non-renewable energy consumption increases CO2 emissions, whereas renewable energy consumption decreases CO2 emissions. Further, the results support the existence of an environmental Kuznets curve between urbanisation and CO2 emissions, implying that at higher levels of urbanisation, the environmental impact decreases. Therefore, the overall evidence suggests that policy makers should focus on urban planning as well as clean energy development to make substantial contributions to both reducing non-renewable energy use and mitigating climate change. © 2013.

Kiani K.,Azad University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2014

Forced vibrations of current-carrying nanowires in the presence of a longitudinal magnetic field are of interest. By considering the surface energy and size effects, the coupled equations of motion describing transverse motions of the nanostructure are derived. By employing Galerkin and Newmark-β approaches, the deflections of the nanowire subjected to transverse dynamic loads are evaluated. The effects of the magnetic field, electric current, pre-tension force, frequency of the applied load, surface and size effects on the maximum transverse displacements are discussed. The obtained results display that for the frequency of the applied load lower than the nanowire's fundamental frequency, by increasing the magnetic field or electric current, the maximum transverse displacements would increase. However, for exciting frequencies greater than that of the nanowire, maximum transverse displacements would increase or decrease with the magnetic field strength or electric current. Additionally, the pre-tension force results in decreasing of the maximum transverse displacements. Such a reduction is more apparent for higher values of the magnetic field strength and electric current. The present study would be useful in the design of the micro- and nano-electro-mechanical systems expected to be one of the most wanted technologies in the near future. © 2014 Elsevier B.V.

Eidiani M.,Azad University
International Review of Electrical Engineering | Year: 2010

Voltage instability and collapse has been the subject of an increasing body of research over the past few years. In this paper, we proposed a new method of assessing static voltage stability in transmission and distribution networks. The proposed method (PM) is fast, accurate and robust. The expanded Newton-Raphson-Seydel (NRS) and Down-Hill (DH) algorithms are used in PM. Moreover, the elimination of the trigonometric terms in power flow equations and Jacobian matrix, will improve the convergence of PM algorithm. Standard CPF, CPF-GMRES and expanded NRS methods are compared to PM. These algorithms are tested on 350 bus transmission and 1316 bus distribution networks. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.

Sabahi F.,Azad University
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011 | Year: 2011

Cloud computing is one of today's most exciting technology because of its cost-reducing, flexibility, and scalability. With the fast growing of cloud computing technology, Data security becomes more and more important in it. In evaluating whether to move to cloud computing, it is important to compare benefits and also risks of it. Thus, security and other existed issues in the cloud cause cloud clients need more time to think about moving to cloud environments. But Security-related topics is one of the most arguable issues in the cloud computing which caused several enterprises looks to this technology uncertainly and move toward it warily. In this paper I try to summarize cloud computing RAS (Reliability, Availability, and Security) issues and also clarify available solution for some of them. In this paper I try to summarize virtualization level of cloud computing security in detailed view. © 2011 IEEE.

Sabahi F.,Azad University
Proceedings - 3rd International Conference on Computational Intelligence, Communication Systems and Networks, CICSyN 2011 | Year: 2011

Vehicular Adhoc network (VANET) is a new form of Mobile Adhoc Network (MANET). It integrates mobile connectivity protocols to expedite data transfer between vehicles as well as between roadside equipment and available traffic in network. In VANET, Wireless device sends information to nearby vehicles, and messages can be transmit from one vehicle to another vehicle. Therefore, using VANET can increase safety and traffic optimization. Similar to other technology, in VANET there are some important and noticeable issues. One of the most important of them is Security. Since the network is open and accessible from everywhere in the VANET radio range, it is expected to be an easy target for malicious users. In this paper, I try to discuss security issues as one of the most important problems in Vehicular Adhoc network. © 2011 IEEE.

Spherical involute surface topography for straight bevel gears including surface coordinates and normals are calculated. The significance of calculation of normal to the surface is mainly because it is needed for ease-off construction, tooth contact analysis and CMM measurement. The calculated surface and normals are then used to establish ease-off topography and the so-called surface of roll angle. The resultant surface of roll angle is used to allocate potential contact lines and contact ratio. The developed approach is applied to an example automotive differential straight bevel gear to calculate tooth surface, ease-off topography and surface of roll angle. Copyright © 2014 SAE International.

Sabahi F.,Azad University
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011 | Year: 2011

Cloud computing is one of today's most exciting technologies due to its ability to reduce costs associated with computing while increasing flexibility and scalability for computer processes. During the past few years, cloud computing has grown from being a promising business idea to one of the fastest growing parts of the IT industry. IT organizations have expresses concern about critical issues (such as security) that exist with the widespread implementation of cloud computing. These types of concerns originate from the fact that data is stored remotely from the customer's location; in fact, it can be stored at any location. Security, in particular, is one of the most argued-about issues in the cloud computing field; several enterprises look at cloud computing warily due to projected security risks. The risks of compromised security and privacy may be lower overall, however, with cloud computing than they would be if the data were to be stored on individual machines instead of in a so called cloud (the network of computers used for remote storage and maintenance). Comparison of the benefits and risks of cloud computing with those of the status quo are necessary for a full evaluation of the viability of cloud computing. Consequently, some issues arise that clients need to consider as they contemplate moving to cloud computing for their businesses. In this paper I summarize reliability, availability, and security issues for cloud computing (RAS issues), and propose feasible and available solutions for some of them. © 2011 IEEE.

Loading Azad University collaborators
Loading Azad University collaborators