STATEMENT OF PROBLEM Impressions are made using high-viscosity putty vinyl polysiloxane impression materials in conjunction with disposable plastic stock trays. The impression materials have been shown to be dimensionally stable. However, it remains unclear if the disposable plastic stock trays are rigid enough to resist deformation thus yielding potentially unreliable results. PURPOSE This s...

tehran shomal highway passes through alborz mountains with a tunnel length of 6400 meters. there are two main tunnels. a full three-dimensional (3d) numerical analysis coupled with elasto-plastic material models was conducted on the inclined access tunnel. bending moment, axial force and the lining displacements due to the internal forces applied on the shotcrete lining are calculated. axial fo...

the ground reaction curve (grc) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. it defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. generally, grc includes descending and ascending branches. according to many researchers, the descending branch trend for the ...

In a perforated well, fluids enter the wellbore through array of perforation tunnels. These perforations are typically distributed in a helical pattern around the wellbore. Available numerical models to simulate production flow into cased-and-perforated vertical wells have complicated boundary conditions or suffer from high computational costs. This paper presents a simple and at the same time ...

environmental variables, including soil water content (swc), act as constraints on crop growth and productivity. therefore, open air (e0), perforated (e1) and non-perforated (e2) plastic housings were used with well-watered (w0), moderately-watered (w1) and water-stressed (w2) bush bean plants to explore the relationships between water-use efficiency (wue), carbon isotope discrimination (δ) and...

The ground reaction curve (GRC) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. It defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. Generally, GRC includes descending and ascending branches. According to many researchers, the descending branch trend for the ...

The load entering from the ground surrounding on the tunnel’s lining is one of the effective parameters in the designation of a tunnel. The amount of this parameter, which is called Rock load in a rocky environment, depends on several factors such as the overburden thickness, geological and geomechanical conditions and the depth of tunnel. In the present study, the amount of rock load for the L...

Abstract—This paper reports an experimental investigation of the energy spectrum of turbulent velocity fields at low Reynolds numbers (Rλ) in grid turbulence. Hot wire measurements are carried out in grid turbulence with subjected to a 1.36:1 contraction of the wind tunnel. Three different grids are used: (i) large square perforated grid (mesh size 43.75 mm), (ii) small square perforated grid (...

  Background Recent studies indicate increased serum amylase in children with acute appendicitis. The objective of the current study was to determine the diagnostic accuracy of raised serum amylase level in prediction of perforated appendicitis in children with acute appendicitis. Materials and Methods In this cross-sectional study, 61 children (aged 3 to 15 years) who underwent appendectomy su...