Sharif Digital Repository

The exact nature of the induced coupled-fields of anisotropic magneto-electro-elastic ellipsoidal inclusions, multi-inclusions, and inhomogeneities with non-uniform eigenfields under polynomial magneto-electro-elastic far-field loadings is of particular interest. For the sake of prediction of the induced coupled-fields of magneto-electro-elastic multi-inclusions due to piecewise polynomial generalized eigenfields several theorems and corollaries are stated and proved. Some classes of impotent generalized eigenfields associated with encapsulated ellipsoidal multi-inclusion result in vanishing generalized disturbance strains within the innermost ellipsoidal domain. On the other hand, it is... 

Three magneto-plasmonic nanohybrids were synthesized using Au- and Ag-coated Fe3O4 nanoparticles (NPs)-modified dual pH- and temperature-responsive triblock copolymer of poly (butyl methacrylate-co-acrylamide-co-methacrylic acid) to serve as drug carriers with potential of using in both photothermal and controlled/targeted chemotherapies. The internal superparamagnetic core gives the carriers targeted-delivery characteristics, and surface plasmon resonance–based noble metallic Au/Ag shells give them on-demand photothermal and photo-triggering release properties. To investigate the effect of coating method on the targeting property of synthesized carriers, Au NPs were attached to the magnetic... 

A new multifunctional filtration membrane was prepared by twofold advantages of conventional polymeric-membrane as the supporting layer and magneto-plasmonic Ag-doped ZnO@Fe3O4/MWCNTs nanocomposite as the functional layer. Poly acrylic acid (PAA)-modified polyamide (PA) discs (PAA-PA) were applied to increase the hydrophilicity of prepared membrane and X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for characterization. The grafting yield of PAA in the pores and on the surface of PA was 17 wt.% and weigh difference between PAA-PA membrane before and after modifying with the photocatalyst was 8.7 mg. The amount of photocatalyst loading in the prepared... 

Eight eco-friendly, and magnetically-separable heterogeneous photocatalysts including five Au nanoparticles (NPs) modified magnetic TiO2@Fe3O4 NPs and three Ag-Au bi-plasmonic NPs-decorated TiO2@Fe3O4 NPs with enhanced photocatalytic performance under visible light were synthesized and used for photodegradation of methyl orange (MO) as a model pollutant in textile wastewater samples. The photocatalytic activity was assessed using two radiation sources namely, an intense linear 532-nm laser and a continuous solar-simulated xenon lamp. Compared to the TiO2 alone, the prepared photocatalysts revealed efficient photocatalytic activity in visible region due to the presence of two localized... 

In this contribution, we have investigated the effects of magnetoelastic loads on free vibration characteristics of the magnetorheological-based sandwich beam. The considered sandwich beam consists of a magnetorheological core with elastic top and base layers. For these means, the structural governing equations are derived using the Hamilton principle and solved by the finite element method. The results are validated in comparison with the existing results in the literature. The effects of variation in the parameters such as magnetic field intensity and the thickness of the core and top layers on the deviation of the first natural frequency and the corresponding loss factor are studied as... 

The current work reveals the exact nature of the induced interior and exterior coupled-fields of magneto-electro-elastic ellipsoidal inclusions with non-uniform generalized eigenfields, consisting of eigenstrain, eigenelectric, and eigenmagnetic fields. The medium has general rectilinear anisotropic elastic moduli, piezoelectric, piezomagnetic, dielectric, magneto-electric, and magnetic permeability tensors. The non-uniform eigenfields are assumed to be representable as the product of any arbitrary functions whose arguments are the equation of the boundary of the ellipsoidal inclusion with homogeneous polynomials. As a special case, it has been proved that the homogeneous polynomial... 

The current work reveals the exact nature of the induced interior and exterior coupled-fields of magneto-electro-elastic ellipsoidal inclusions with non-uniform generalized eigenfields, consisting of eigenstrain, eigenelectric, and eigenmagnetic fields. The medium has general rectilinear anisotropic elastic moduli, piezoelectric, piezomagnetic, dielectric, magneto-electric, and magnetic permeability tensors. The non-uniform eigenfields are assumed to be representable as the product of any arbitrary functions whose arguments are the equation of the boundary of the ellipsoidal inclusion with homogeneous polynomials. As a special case, it has been proved that the homogeneous polynomial... 

Today, MEMS have wide applications in modern technologies. Magneto hydro dynamic (MHD) micropumps play an important role in the MEMS industry and have been thoroughly studied in the recent years. In this study, the idea of classic reciprocating micropumps was combined with magneto hydro dynamics (MHD) to develop a novel Magneto Mercury Reciprocating (MMR) micropump. To attain this goal, the Lorentz force, as the actuation mechanism, was used to move a conductive liquid (mercury) slug in a reciprocating manner in order to suck the working fluid (air) from the inlet and pump it to the outlet. The performance of the fabricated MMR micropump was examined in terms of parameters such as pressure... 

The propagation of shear horizontal surface acoustic waves (SHSAWs) in an inhomogeneous magneto-electro-elastic (MEE) half-space with 6-mm symmetry is studied. By virtue of both the direct approach and Stroh-formalism, the dispersion relations corresponding to two general cases of material properties variation are obtained. In the first case, it is assumed that all material properties involving the MEE properties and density vary similarly in depth, whereas, the second case considers identical variation for the MEE properties, which differs from the variation of the density. The non-dispersive SHSAW velocities pertinent to the homogeneous MEE media are obtained under eight different surface... 

Laminated composite structures are widely being used in modern industries particularly robot arms, aerospace and wind turbine blades where the structures mainly exposed to harsh random vibration and in turn, leads to unpredicted failure. Adding Magneto-rheological (MR) fluids in such structures may significantly improve their dynamic response. In the present work, the vibration response of laminated composite beams filled with MR fluids (MR laminated beam) under random loading has been investigated using experimental as well as simulation approaches. Finite Element Model (FEM) has been utilized to simulate the vibration response under random loading. An in-house set-up has been designed to... 

This paper presents a three-dimensional phenomenological constitutive model for magnetic shape memory alloys (MSMAs), developed within the framework of irreversible continuum thermodynamics. To this end, a proper set of internal variables is introduced to reflect the microstructural consequences on the material macroscopic behavior. Moreover, a stress-dependent thermodynamic force threshold for variant reorientation is introduced which improves the model accuracy. Preassumed kinetic equations for magnetic domain volume fractions, decoupled equations for magnetization unit vectors and appropriate presentation of the limit function for martensite variant reorientation lead to a simple... 

In this article, free vibration behavior of a rotating nano/microcircular plate constructed from functionally graded magneto-elastic material is simulated with the first-order shear deformation theory. For the sake of comparison, the nonlocal elasticity theory and the modified couple stress theory are employed to implement the small size effect in the natural frequencies behavior of the nano/microcircular plate. The governing equations of motion for functionally graded magneto-elastic material nano/microcircular plates are derived based on Hamilton’s principle; comparing the obtained results with those in the literature, they are in a good agreement. Finally, the governing equations are... 

This article presents a modified Green–Lindsay (MG-L) thermoelasticity model considering temperature and strain rate. Previously, this model has been developed based on the Green–Lindsay theory of thermoelasticity using strain and temperature rate dependent thermoelastic equations. This study analyzes stress and thermal wave propagation of a functionally graded medium exposed to an electromagnetic field and a thermal shock. All magnetic, elastic, and thermal features of the medium are considered to vary in the longitudinal direction. Additionally, the properties of the material are dependent on the temperature in the form of a cubic function. Using the large displacement formulation and the... 

This article presents a modified Green–Lindsay (MG-L) thermoelasticity model considering temperature and strain rate. Previously, this model has been developed based on the Green–Lindsay theory of thermoelasticity using strain and temperature rate dependent thermoelastic equations. This study analyzes stress and thermal wave propagation of a functionally graded medium exposed to an electromagnetic field and a thermal shock. All magnetic, elastic, and thermal features of the medium are considered to vary in the longitudinal direction. Additionally, the properties of the material are dependent on the temperature in the form of a cubic function. Using the large displacement formulation and the...