Kamarian S.,Islamic Azad UniversityKermanshah |
Salim M.,Amirkabir University of Technology |
Dimitri R.,University of Salento |
Tornabene F.,University of Bologna
International Journal of Mechanical Sciences | Year: 2016
In the present work, a free vibration analysis of Carbon Nanotube-Reinforced Composite (CNTRC) conical shells is performed considering the agglomeration effect of Carbon Nanotubes (CNTs). The material properties of the nanocomposite conical shell are estimated employing the Eshelby-Mori-Tanaka approach based on an equivalent fiber assumption. The numerical results are compared with the experimental data available from the literature. The equations of motion are derived based on the First-order Shear Deformation Theory (FSDT). The Generalized Differential Quadrature (GDQ) technique is originally implemented to solve the governing equations of the problem and to obtain the natural frequencies of the structures, since it has proven to be an efficient and accurate numerical tool. A parametric study is herein developed to investigate the influence of some characteristic parameters on the vibrational behavior of the CNTRC conical shell, e.g. the CNTs volume fraction and agglomeration, or the boundary conditions and geometrical parameters like the thickness to radius ratio. Based on results, it is found that agglomeration of CNTs plays a significant role on the natural frequency of the structure. © 2016 Elsevier Ltd. All rights reserved.
Bagheri G.,Islamic Azad UniversityKermanshah |
Hosseini S.E.,University of Technology Malaysia
Energy Conversion and Management | Year: 2015
Abstract Flame stability and thermal performance of two different heat recirculation micro-combustors (inner reactor heat recirculation (IHR) and outer reactor heat recirculation (OHR)) are investigated using computational fluid dynamics (CFD) and compared together. A two-dimensional steady state CFD model including temperature dependent properties, laminar flow and transport, one step chemical reaction, surface-to-surface radiation, and heat conduction within solid walls has been carried out to assess flame propagation velocity, flame thickness, excess enthalpy, heat loss, and emitter efficiency. It is observed that both cases significantly extend flammability and blow-off limits due to preheating of the reactive mixture. The maximum flame propagation velocities of IHR and OHR in stoichiometric mixture are predicted 160.2 cm/s and 126.1 cm/s, respectively. It is found that super-adiabatic flame temperature takes place when dimensionless excess enthalpy is positive and it is maximum in the stoichiometric equivalence ratio. Heat loss can be varied from 245.8 to 248.6 W for IHR and from 249.6 to 254 W for OHR configuration. Therefore, there is a relative improvement in the Thermal quenching limit of IHR. It is concluded that IHR micro-combustor profoundly affects flame characteristic and stability, but OHR presents a higher range of emitter efficiency. © 2015 Elsevier Ltd.
Kahrarian M.,Islamic Azad UniversityKermanshah |
Baltanas R.M.,University of Cordoba, Spain |
Monshizadeh M.R.,Islamic Azad UniversityKermanshah |
Shenavaee M.R.,Islamic Azad UniversityKermanshah
Entomologia Generalis | Year: 2014
In this study, we investigated the fauna of Lepismatidae in different regions of Kermanshah province (Kermanshah, Sar-e-pol-e- Zahab, Paveh and Eslamabad-e-gharb counties) during 2012 and 2013. The specimens were collected by hand or with an entomological aspirator from leaf litter, under rocks and in different parts of the house. Totally 7 species were found, belonging to 5 genera and 3 subfamilies. The species, Ctenolepisma rothschildi, Thermobia aegyptiaca, Allacrotelsa kraepelini and Neoasterolepisma evansi are new records for the fauna of Iran. © 2014 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Amirian M.,Islamic Azad UniversityKermanshah |
Karimi G.,Razi UniversityKermanshah |
Lalbakhsh A.,Islamic Azad UniversityKermanshah |
Bayati M.-S.,Razi UniversityKermanshah
Microelectronics Journal | Year: 2015
Abstract A compact differential band pass filter with asymmetric parallel-coupled lines (APCL) and center frequency of 5.6 GHz is proposed in this paper. The APCL suppresses unwanted RFID signals by introducing a fully tunable notched band at 6.8 GHz. By combining the concept of transmission matrix with modal analysis and extracting a novel model for symmetric three parallel coupled lines (SPCL), role of each resonant frequency is clearly explained. Measurement results in the differential mode show a pass band from 3.1 to 8.1 GHz and a wide stop band from 9.1 to 16 GHz with attenuation of more than 20 dB. In addition, S21 in common mode is lower than -10.5 dB over the pass band. © 2015 Elsevier Ltd.