the high costs of experimental works on the nanocomposites can be reduced through implementation of analytical and numerical studies. to study the effect of impact energy on the nanocomposites, a nanocomposite composedof polyurethane and clay nanoparticles is selected as a case study. the finite element modeling is carried out using the ansys software, and the impact analysis is performed using...

background and aims. heat generated within tooth during clinical dentistry can cause thermally induced damage to hard and soft components of the tooth (enamel, dentin and pulp). geometrical characteristics of immature teeth are different from those of mature teeth. the purpose of this experimental and theoretical study was to investigate thermal changes in immature permanent teeth during the us...

objective: in all ceramic fixed partial dentures the connector area is a common fracture location. the survival time of three-unit fixed partial dentures may be improved by altering the connector design in regions of maximum tension. the purpose of this study was to determine the effect of buccolingual increase of the connector width on the stress distribution in posterior fixed partial denture...

o bjectives: headgears are among the effective orthodontic appliances to achieve treatment goals. unilateral molar distal movement is sometimes needed during an orthodontic treat- ment, which can be achieved by an asymmetric headgear. different unilateral headgears have been introduced. the main goal of this study was to analyze the force system of uni- lateral expanded outer bow asymmetric hea...

introduction: the fracture strength of endodontically treated teeth compared to vital ones has long been a source of controversy. it is not clear how root canal therapy affects the stress distribution in teeth. the purpose of this study was to evaluate the changes in stress distribution after root canal therapy in a human maxillary canine by finite element analysis (fem). materials and methods:...

Higher order and spectral methods have been used with success for elliptic and parabolic initial and boundary value problems with smooth solutions. On the other hand, higher order methods have been applied to hyperbolic problems with less success, as higher order approximations of discontinuous solutions suffer from the Gibbs phenomenon. We extend past work and show that spectral methods yield ...

In this paper, we propose a numerical method to approximate the solution of partial differential equations in irregular domains with no-flux boundary conditions by means of spectral methods. The main features of this method are its capability to deal with domains of arbitrary shape and its easy implementation via Fast Fourier Transform routines. We discuss several examples of practical interest...

We present constructive a priori error estimates forH 0 -projection into a space of polynomials on a one-dimensional interval. Here, “constructive” indicates that we can obtain the error bounds in which all constants are explicitly given or are represented in a numerically computable form. Using the properties of Legendre polynomials, we consider a method by which to determine these constants t...

We study wave propagation in periodic and frequency dependent materials. The approach in this paper leads to spectral analysis of a quadratic operator pencil where the spectral parameter relates to the quasimomentum and the frequency is a parameter. We show that the underlying operator has a discrete spectrum, where the eigenvalues are symmetrically placed with respect to the real and imaginary...

In order to diagnose the unbalance of aerostatic guideways, displacement and acceleration sensors were used to measure the vibration signals of the unbalance of the aerostatic guideways caused by the gas fluctuation. The frequency characteristics for the unbalance of aerostatic guideways caused by gas fluctuation has been extracted from the measured signals by power spectral density, and the ba...