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...

A study of steady lift interference effects in wind tunnels with several different wall conditions has been carried out using a three-dimensional resistance network. The methods by which the various boundary conditions were simulated on the network are described in detail; conditions included closed, open, slotted and perforated walls. The evaluation of interference parameters is described, and...

We present the design, fabrication, and performance analysis for a class of two-dimensional acoustic cloaking coatings in air. Our approach takes advantage of transformation acoustics and linear coordinate transformations that result in shells which are homogeneous, broadband, and compact. The required material parameters are highly anisotropic; however, we show that they are easily achievable ...

FOR many years I have used perforated solid glass necklace beads of various sizes for the above purpose. They -were perhaps not so suitable as carbonized bone or gold basket spheres but were much easier to obtain than the former and far cheaper than the latter. Most of the other materials used for implantation have greater or lesser disadvantages; e.g., hollow glass spheres -may burst, smooth u...

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 ...

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...

We investigate the mechanical response of thin sheets perforated with a square array of mutually orthogonal cuts, which leaves a network of squares connected by small ligaments. Our combined analytical, experimental and numerical results indicate that under uniaxial tension the ligaments buckle out of plane, inducing the formation of 3D patterns whose morphology is controlled by the load direct...

energy-based optimized design of polymer fiber-reinforced tunnel lining mohammad safi                   analysis of underwater tunnels considering strain-softening behavior in plastic zone ahmad fahimifar; hamed ghadami; masoud ahmadvand; arvin abdolmaleki                                 the effect of operational parameters on penetration rate of a tbm using artificial neural networks- a case s...

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 ...