SYNTHESIS AND CHARACTERIZATION OF BIOACTIVE GLASS/FORSTERITE NANOCOMPOSITES FOR BONE AND DENTAL IMPLANTS

In this research, bioactive glass (BG) of the type CaO–P2O5–SiO2 and nanocrystalline forsterite (NF) bioceramic were successfully synthesized via sol–gel processing method. Heat-treatment process was done to obtain phase-pure nanopowders. After characterization of each sample, the nanocomposite samples were prepared by cold pressing method and sintered at 1000°C. The samples were fully characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) analyses. The average nanocrystallite size was determined using the Debye-Scherrer’s formula 19.6 nm. The bioactivity was examined in vitro with respect to the ability of hydroxyapatite (HAp) layer to form on the surfaces as a result of contact with simulated body fluid (SBF). According to the obtained results, the prepared nanocomposite enhances the fracture toughness of the BG matrix without deteriorating its intrinsic properties as bioactivity

Buckling behavior of clamped laminated composite cylindrical shells under external pressure using finite element method

In this study, the elastic buckling behavior of clamped laminated composite cylindrical shells under external pressure was studied. The Finite Element Method (FEM) was used to predict the critical elastic buckling pressure behavior when composite cylindrical shells were subjected to external pressure. The edges of the cylindrical shell ends were completely constrained to simulate clamped end conditions. The influences of parameters such as wall thickness, fiber angle, number of layers and L/R ratio of laminated composite cylindrical shells on critical buckling pressure were studied. It has been found that the under external pressure, the thickness and the fiber angle of the layers have the most significant effect on the critical buckling pressure

Imperialist competitive algorithm and its application in optimization of laminated composite structures

This paper presents an application of the imperialist competitive algorithm (ICA) in optimization of composite structures design. The recently introduced algorithm has proven its excellent capabilities, such as faster convergence and better global optimum achievement. In this paper, imperialist competitive algorithm (ICA) is used to demonstrate its application in finding the optimal design of laminated composite structures due to the various failure criteria. The proposed method can be used in various multi-objective optimization problems. The effectiveness of the proposed method, in comparison to Genetic Algorithm (GA), is proven through solving several examples of composite structure problems

Imperialist competitive algorithm and its application in optimization of lamited composite structures

This paper presents an application of the imperialist competitive algorithm (ICA) in optimization of composite structures design. The recently introduced algorithm has proven its excellent capabilities, such as faster convergence and better global optimum achievement. In this paper, imperialist competitive algorithm (ICA) is used to demonstrate its application in finding the optimal design of laminated composite structures due to the various failure criteria. The proposed method can be used in various multi-objective optimization problems. The effectiveness of the proposed method, in comparison to Genetic Algorithm (GA), is proven through solving several examples of composite structure problems

Imperialist competitive algorithm for multiobjective optimization of ellipsoidal head of pressure vessel

This work devoted to an ellipsoidal head of pressure vessel under internal pressure load. The analysis is aimed at finding an optimum weight of ellipsoidal head of pressure vessel due to maximum working pressure that ensures its full charge with stresses by using imperialist competitive algorithm and genetic algorithm. In head of pressure vessel the region of its joint with the cylindrical shell is loaded with shear force and bending moments. The load causes high bending stresses in the region of the joint. Therefore, imperialist competitive algorithm was used here to find the optimum shape of a head with minimum weight and maximum working pressure which the shear force and the bending moment moved toward zero. Two different size ellipsoidal head examples are selected and studied. The imperialist competitive algorithm results are compared with the genetic algorithm results

Optimum size of a ground-based cylindrical liquid storage tank under stability and strength constraints using imperialist competitive algorithm

Steel cylindrical tank is one of the most common forms of liquid storage vessels. In this study the Imperialist Competitive Algorithm (ICA) is used to find the optimum size of a ground based cylindrical liquid storage tank that is supported at both ends and the design considerations are stability and strength constraints. In this study total internal pressure and total special pressure are assumed as two types of load. The optimization procedure is formulated with the objective to minimize the mass of the tank due to the allowable capacity of cylindrical tank