University of Bonab

Bonāb, Iran

University of Bonab

Bonāb, Iran
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Fallahi V.,University of Bonab
Journal of Superconductivity and Novel Magnetism | Year: 2017

The ballistic magnetoresistance of a geometrically confined 180 ∘ head-to-head domain wall at a magnetic point contact in a two-dimensional (2D) metallic nanowire is studied theoretically using the multichannel Landauer-Büttiker formalism. The analysis is based on coherent scattering of the carriers by the spin-dependent potential associated with the wall structure. The transmission properties of coherent states are obtained by introducing a new algorithm to solve the coupled spin channels Schrödinger equations with mixed Dirichlet-Neumann boundary conditions applied far from the domain wall. The conductance and thermally averaged magnetoresistance of the domain wall are computed to evaluate the performance of the proposed algorithm. As expected, an oscillatory behavior with successively decreasing extrema is achieved in the magnetoresistance by increasing the domain wall width. © 2017 Springer Science+Business Media New York

Abdi-Ghaleh R.,University of Bonab
Applied Optics | Year: 2017

In this paper, we have proposed a dual-channel magnetic field sensor based on magnetophotonic heterostructures. This sensor provides the capability of simultaneous measurement of a magnetic field with two different light wavelengths. The utilized magnetophotonic heterostructure is constituted of two one-dimensional microcavity-type magnetophotonic crystals with different design wavelengths. The magneto-optical characteristics of the separate microcavity structures and the heterostructure have been investigated using the 4 by 4 transfer matrix method. The transmittance and Faraday rotation spectra of the structures and the behavior of the resonance modes have been studied. Finally, the operation of the proposed sensor has been explained. © 2017 Optical Society of America.

The application of post treatments in preparation of high flux membranes is expanding rapidly. In this work, several hybrid post treatments have been introduced and used for change in the water flux of polysulfone (PSf) hollow fiber membranes. Dry wet spinning method was employed for fabrication of PSf hollow fiber membrane from spinning dope in mass ratio of 15:5:80 of PSf/PVP-K90/NMP. The simultaneous effects of single and hybrid post treatments containing traditional hypochlorite; high pressure injection technique (HPI) of hypochlorite, hot air and hot water treatments on the morphology and water flux of fabricated hollow fibers has been investigated. AFM analysis and image processing of SEM microphotographs of hollow fibers were used for structural studies. The mechanical properties of hollow fibers as well as strain at break and strength also were studied. It was found that the pores size and surface roughness parameter of hollow fiber membranes have been increased after traditional hypochlorite, HPI technique and hot water treatments while decreased when heat treated in air. In general all the employed hybrid post treatments caused to increase in the pores size of hollow fibers although the pores size increase rate in the membranes treated by the hybrid post treatments involving hot air was much lower than the others. The mechanical properties of hollow fibers have been decreased after hybrid and single post treatments containing traditional hypochlorite, HPI technique and hot water treatment while slightly increased after post treatments containing hot air. It was stated that the fabricated PSf hollow fibers were considerably affected by the employed hybrid post treatments. This can be attributed to the combine effects of used post treatments. © 2017, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Hashemi M.S.,University of Bonab
European Journal of Mechanics, B/Fluids | Year: 2017

In this paper, we propose a simple and easy-to-implement numerical algorithm based on the GL6(R) Lie group, for the solution of magneto-hemodynamic (MHD) flow in a semi-porous channel by transforming the governing equations into a nonlinear system of six first-order ordinary differential equations (ODEs). Innovative Lie-group method, allows us to search missing initial slopes at the left-ends, and moreover, the initial slopes can be expressed as closed-form functions of r∈(0,1), where the best r is determined by matching the right-end boundary conditions. The influence of transpiration Reynolds number (mass transfer parameter, Re) and Hartmann number (H) on the velocity profiles in the channel are considered graphically. Finally, the reported results are compared with those calculated by numerical method (NM) which illuminate the efficiency and precision of GL6(R) Lie group method for this problem. © 2017 Elsevier Masson SAS

Hatami M.,University of Bonab | Yazdan Panah M.,University of Bonab
Ultrasonics Sonochemistry | Year: 2017

In this study, phenol-formaldehyde (PF)/CeO2 nanocomposites (NC)s were prepared by in-situ polymerization of phenol and formaldehyde in alkali solution in the presence of surface modified CeO2 nanoparticles (NP)s by sonochemical assisted synthesis. The morphology and structure of PF/CeO2 NCs were characterized by using fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal analyses methods. It was found that due to the good dispersion of surface modified NPs in polymer matrix and the strong interfacial interaction between the CeO2 NPs and PF matrix, the thermal stability and thermo-mechanical properties of the PF/CeO2 NCs were greatly enhanced. FE-SEM and AFM analyses showed the uniform distribution of CeO2 NPs in PF matrix. The XRD patterns of NCs show the presence of crystalline CeO2 NPs in amorphous matrix. The thermal analysis results reveal that, with increases in the content of CeO2 NPs in PF matrix, the thermally stability factors of samples were drastically enhanced. © 2017 Elsevier B.V.

Abdi-Ghaleh R.,University of Bonab | Asad M.,Shiraz University
European Physical Journal D | Year: 2015

In this paper, a proposal for designing the one-dimensional magnetophotonic crystals operating at visible wavelengths is presented. To this aim, a binary all-dielectric periodic structure is considered with quarter wavelength optical thicknesses condition. However, the Bi:YIG as a magneto-optical defect layer with two different optical thicknesses of λ 0 /2 and 4eλ0 is utilized. Using the 4 × 4 transfer matrix method the defect mode properties of the considered structures are investigated regarding the different period numbers and various magneto-optical defect layer positions. Analyzing the transmittance, Faraday rotation and absorption coefficient of these structures for the 720 nm visible light, the optimum structures are proposed for both cases of magneto-optical defect layer thicknesses. These structures may have potential applications in designing the miniaturized magneto-optical devices such as magneto-optical sensors and isolators and integrated photonic elements. ©EDP Sciences Società Italiana di Fisica Springer-Verlag 2015.

In this paper, we introduce a general iterative algorithm for finding the common element of the set of common fixed points of an infinite family of nonexpansive mappings, the set of solutions of systems of equilibrium problems and the set of solutions of systems of variational inequalities for two strongly monotone mappings in a real Hilbert space. Then, we prove a strong convergence theorem of the iterative sequence generated by the proposed iterative algorithm under some suitable conditions. Our results improve and extend the corresponding results announced by Colao and Marino [V. Colao and G. Marino, strong convergence for a minimization problem on points of equilibrium and common fixed points of an infinite family of nonexpansive mappings, Nonlinear Anal. (2010) 3513-3524] and many others. © 2011 Elsevier Ltd.

Abdi-Ghaleh R.,University of Bonab | Mohiabadi H.N.,University of Bonab
European Physical Journal D | Year: 2016

In this paper the magneto-optical responses of single-cavity and dual-cavity type one-dimensional magnetophotonic crystals have been investigated considering the constituent layers optical dispersion in near infrared region. The 4 × 4 transfer matrix method has been utilized for calculations and analysis. The obtained results revealed that the resonance transmittance mode is split into two separated modes for specific repetition numbers. These modes are shifted toward the center of photonic band gap regarding the stronger dispersion relations, in both single- and dual-cavity structures. But the amounts of the shifts and their fine behavior are strongly dependent on the type of the structure. We believe that the results of the present work would be practically helpful to precisely design the miniaturized magneto-optical elements in micro- and nano-scale. © 2016 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Poursamad J.B.,University of Bonab
Optik | Year: 2016

A new method of inducing thermomechanical hydrodynamic flow in homeotropic nematic liquid crystals (NLC) is proposed based on using different anchoring conditions on the cell boundaries. Effect of different pairs of boundary conditions including hard, weak and conical on the director orientation, director gradient and NLC flow are studied, theoretically. Absorption of a linearly polarized laser light is considered to induce the need temperature gradient for the thermomechanical effect (TM) in the NLC cell. Coupling of fluidity to the director orientation distorts the director. Consequent optical nonlinearity is calculated and compared with the optical nonlinearity due to other kinds of the TM effect. © 2016 Elsevier GmbH. All rights reserved.

Hashemi M.S.,University of Bonab
Physica A: Statistical Mechanics and its Applications | Year: 2015

In this paper, the Lie symmetry analysis method is extended to deal with the nonlinear time fractional Fokker-Planck (FP) equation with Riemann-Liouville derivative. The Erdélyi-Kober fractional derivative which is depending on a parameter α, is used for the reduction of FP equation. Symmetry reduction is provided and some exact analytic solutions to the time fractional FP equation are investigated by virtue of the reduction method introduced by M.C. Nucci. © 2014 Elsevier B.V. All rights reserved.

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