introduction: mandibular first molar is the most important tooth with complicated morphology. in finite element (fe) studies, investigators usually prefer to model anterior teeth with a simple and single straight root; it makes the results deviate from the actual case. the most complicated and time-consuming step in fe studies is modeling of the desired tooth, thus this study was performed to e...

in this research between 3-dimensional and axisymmetric modeling for movement of nano-particles in passing through a aerodynamic lens, and also between these models and famous model of wang & liu was compared. for this purpose, output of nano-particles penetration, divergence angel, and nano-particle velocity with wang & liu model was compared. geometrical model used for aerodynamic lens compar...

The present work solves two-dimensional Advection-Dispersion Equation (ADE) in a semi-infinite domain. A variable source concentration is regarded as the monotonic decreasing function at the source boundary (x=0). Depth-dependent variables are considered to incorporate real life situations in this modeling study, with zero flux condition assumed to occur at the exit boundary of the domain, i.e....

earthquakes could have catastrophic impacts on tunnels and buried structures. liquefaction phenomenon is one of the most destructive effects of earthquakes. liquefaction results in decreasing effective stress and this consequently leads to decreases in shear strength of the soil. as a result, large deformation in both soil and buried structure occurs. moreover, liquefaction causes soil boiling,...

A three-dimensional model of a circulating fluidized bed gasifier was developed, which uses continuous radial profiles of velocities and solids hold-up with regard to the description of fluid mechanics. A complex reaction network of sewage sludge gasification is included in the model. In the simulation calculations the influence of the axial location and the number of feeding points was examine...

Ultraviolet waves, because of their short wavelength, have a high energy and considerable damaging effects on surfaces. Protection against ultraviolet radiations is one of the finishing treatments done on surfaces exposed to sunlight. The importance of this issue in relation to human health, due to complications such as skin burns and cancer, is doubled. Up t...

In this paper, the optical properties of one dimensional fractal structures are investigated. We consider six typical fractal photonic structures: the symmetric dual cantor-like fractal structure, the asymmetric dual cantor-like fractal structure, the single cantor-like fractal structure, the symmetric dual golden-section fractal structure, the asymmetric dual golden-section fractal structure a...

this research is carried out to design and manufacturing of lathe vibration tool and their tests. firstly, one-dimensional vibration tool is designed and made of the bending vibration mode. one-dimensional vibration tool with half piezoelectric rings is considered to excite the bending mode of tool. structure of vibration tool is designed in abaqus software about 20 khz and then is made with re...

The present work solves two-dimensional Advection-Dispersion Equation (ADE) in a semi-infinite domain. A variable source concentration is regarded as the monotonic decreasing function at the source boundary (x=0). Depth-dependent variables are considered to incorporate real life situations in this modeling study, with zero flux condition assumed to occur at the exit boundary of the domain, i.e....