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ON KIRCHHOFF TYPE EQUATIONS WITH SINGULAR NONLINEARITIES, SUB-CRITICAL AND CRITICAL EXPONENT
M. El Mokhtar Ould El Mokhtar,Saleh Fahad Aljurbua 경남대학교 수학교육과 2024 Nonlinear Functional Analysis and Applications Vol.29 No.2
This paper is devoted to the existence of solutions for Kirchhoff type equations with singular nonlinearities, sub-critical and critical exponent. By using the Nehari manifold and Maximum principle theorem, the existence of at least two distinct positive solutions is obtained.
Mokhtar Ellali,Khaled Amara,Mokhtar Bouazza,Fouad Bourada 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.1
In this article, an exact analytical solution for mechanical buckling analysis of magnetoelectroelastic plate resting on pasternak foundation is investigated based on the third-order shear deformation plate theory. The in-plane electric and magnetic fields can be ignored for plates. According to Maxwell equation and magnetoelectric boundary condition, the variation of electric and magnetic potentials along the thickness direction of the plate is determined. The von Karman model is exploited to capture the effect of nonlinearity. Navier\'s approach has been used to solve the governing equations for all edges simply supported boundary conditions. Numerical results reveal the effects of (i) lateral load, (ii) electric load, (iii) magnetic load and (iv) higher order shear deformation theory on the critical buckling load have been investigated. These results must be the analysis of intelligent structures constructed from magnetoelectroelastic materials.
Thermal buckling of porous FGM plate integrated surface-bonded piezoelectric
Mokhtar Ellali,Khaled Amara,Mokhtar Bouazza Techno-Press 2024 Coupled systems mechanics Vol.13 No.2
In the present paper, thermal buckling characteristics of functionally graded rectangular plates made of porous material that are integrated with surface-bonded piezoelectric actuators subjected to the combined action of thermal load and constant applied actuator voltage are investigated by utilizing a Navier solution method. The uniform temperature rise loading is considered. Thermomechanical material properties of FGM plates are assumed to be temperature independent and supposed to vary through thickness direction of the constituents according to power-law distribution (P-FGM) which is modified to approximate the porous material properties with even and uneven distributions of porosities phases. The governing differential equations of stability for the piezoelectric FGM plate are derived based on higher order shear deformation plate theory. Influences of several important parameters on the critical thermal buckling temperature are investigated and discussed in detail.
Ellali, Mokhtar,Amara, Khaled,Bouazza, Mokhtar,Bourada, Fouad Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.1
In this article, an exact analytical solution for mechanical buckling analysis of magnetoelectroelastic plate resting on pasternak foundation is investigated based on the third-order shear deformation plate theory. The in-plane electric and magnetic fields can be ignored for plates. According to Maxwell equation and magnetoelectric boundary condition, the variation of electric and magnetic potentials along the thickness direction of the plate is determined. The von Karman model is exploited to capture the effect of nonlinearity. Navier's approach has been used to solve the governing equations for all edges simply supported boundary conditions. Numerical results reveal the effects of (i) lateral load, (ii) electric load, (iii) magnetic load and (iv) higher order shear deformation theory on the critical buckling load have been investigated. These results must be the analysis of intelligent structures constructed from magnetoelectroelastic materials.
Speed of random walk and resistance
Mokhtar Konsowa,Tamer Oraby 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.4
We give a simple formula to calculate the speed of weighted random walks on nonnegative integers and on spherically symmetric trees.
Synthesis and characterization of CeO2 nanoparticles via hydrothermal route
Mokhtar Panahi-Kalamuei,Sakineh Alizadeh,Mehdi Mousavi-Kamazani,Masoud Salavati-Niasari 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Cerium oxide (CeO2) nanoparticles have been synthesized from (NH4)2Ce(NO3)6, ethylenediamine andhydrazine by a hydrothermal method. Ethylenediamine and hydrazine with pH management can controlthe particle growth and have an important role in the formation of nanoparticles. Various experimentalparameters were examined, such as the reaction temperature, the reaction time, and the molar ratios ofthe starting reagents. The as-synthesized products were characterized by powder X-ray diffraction(XRD), transmission electronmicroscopy (TEM), scanning electronmicroscopy (SEM), Fourier transforminfrared spectroscopy (FT-IR), and energy dispersive X-ray spectroscopy (EDX).
Mokhtar Ansari,Farhad Daneshjoo,Amir Safiey,Naser Safaeian Hamzehkolaei,Maryam Sorkhou 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.3
Utilization of fiber beam-column element has gained considerable attention in recent years due mainly to its ability to model distributed plasticity over the length of the element through a number of integration points. However, the relatively high sensitivity of the method to modeling parameters as well as material behavior models can pose a significant challenge. Residual drift is one of the seismic demands which is highly sensitive to modeling parameters and material behavior models. Permanent deformations play a prominent role in the post-earthquake evaluation of serviceability of bridges affected by a near-fault ground shaking. In this research, the influence of distributed plasticity modeling parameters using both force-based and displacement-based fiber elements in the prediction of internal forces obtained from the nonlinear static analysis is studied. Having chosen suitable type and size of elements and number of integration points, the authors take the next step by investigating the influence of material behavioral model employed for the prediction of permanent deformations in the nonlinear dynamic analysis. The result shows that the choice of element type and size, number of integration points, modification of cyclic concrete behavior model and reloading strain of concrete significantly influence the fidelity of fiber element method for the prediction of permanent deformations.
Mokhtar Arazpour,Aliyeh Daryabor,Navid Golchin 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.5
The aim of this literature review was to evaluate selected original papers that measured gait parameters and energy expenditure in idiopathic scoliosis (IS) treated with surgical intervention. IS is a progressive growth disease that affects spinal anatomy, mobility, and left–right trunk symmetry. Consequently, IS can modify human gait. Spinal fusions remain the primary approach to correcting scoliosis deformities, thereby halting progression. Using the population intervention comparison outcome measure framework and selected keywords, 15 studies that met the inclusion criteria were selected. Alteration of spatial and temporal variables in patients with IS was contradictory among the selected studies. Ankle and foot kinematics did not change after surgery; however, pelvic and hip frontal motions increased and pelvic rotation decreased following surgery. Patients with IS continued to show excessive energy expenditure following surgery in the absence of a physical rehabilitation protocol. Spinal surgery may be considered for gait improvement and IS treatment. There were inadequate data regarding the effect of corrective surgery on the kinetics, energy expenditure, and muscle activity parameters.
Mokhtar Ansari,Amir Safiey 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.4
Today, the use of special technologies in the admixture of concrete has made tremendous progress, but the problem that has always existed in the construction of concrete members is the brittleness and lack of loading bearing after cracking, which leads to reduced strength and energy absorption. One of the best ways to fix this is to reinforce the concrete with steel fibers. Steel fibers also control cracks due to dry shrinkage, reduce structural crack width, and improve impact resistance. In this study, recycled steel fibers from worn tires have been used in the manufacture of concrete samples, the secondary benefits of which are the reduction of environmental pollution. One of the disadvantages of steel fiber reinforced concrete is the corrosion of steel fibers and their deterioration in harsh environments such as coastal areas. Corrosion caused by chlorine ions in metal fibers causes deterioration and early decommissioning of structures in corrosive environments. In this study, the effect of the dosage of steel fibers (dosages of 15, 30, and 45 kg of fibers per cubic meter of concrete) and aspect ratio of fibers (aspect ratio of 25 and 50) on compressive and flexural strength of concrete samples are investigated. In the following, the effect of fiber corrosion on the results of the mechanical properties of concrete samples is examined. The results show that the increase in fiber causes a relative increase in compressive strength, and a significant increase in flexural strength, and corrosion of steel fibers without reducing workability reduces compressive strength and flexural strength by up to 6 to 11%, respectively.