the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) was used to predict the barrier insertion loss. the results of rigid and with absorptive coverage were also calculated for comparisons. using qrd on the top surface and faces of all vertical profil...

The aim of this research was manufacturing a parabolic trough solar collector in which reflecting surface is made of mirror steel rather than usual mirror and also predicting its theoretical performance.by adjusting planar ⩝ -shaped structures parallel to each other and welding them together, the main supporting structure was assembled and a parabolic-shape Teflon arc was installed in the apert...

The mol-ecular structure of the title compound, [Fe(C9H6BrS)(C13H7F6)], consists of a ferrocene backbone with a bis-(tri-fluoro-meth-yl)phenyl group at one cyclo-penta-dienyl ring and a thio-phene heterocycle at the other cyclo-penta-dienyl ring. The latter is disordered over two sets of sites in a 0.6:0.4 ratio. In the crystal structure, intra-molecular π-π inter-actions between the thienyl an...

We study Na+N(2) collisions by laser excitation of the collision complex in a differential scattering experiment. The measured relative population of the Na(3p) fine-structure levels reflects the nonadiabatic transitions occurring in the exit channel of the collision. Theoretical results obtained with a classical-path formalism and accurate quantum chemical data for NaN(2) are found to be in go...

C-shaped canals are mostly found in mandibular second molars. Studies have shown that frequency ranges from 2.7 to 31%. This study was undertaken to provide further knowledge of the distribution of such canal anatomy, by determining the frequency of C-shaped canals in a sample representing the Lebanese population. Ninety-four mandibular second molars with scheduled endodontic treatment were exa...

Underwater explosion seriously affects the combat performance and vitality of submarines. In order to improve blast resistance stiffened double cylindrical shells, a new type style that replaces traditional T-shaped stiffeners with circular tube stiffeners, namely O-shaped are studied. A series comparative underwater tests carried out on two scaled shells O stiffeners. Based tests, more detaile...

In this paper two –dimensional square shaped photonic crystal ring resonator based NOT logic gate is proposed. The numerical, structural, theoretical analysis is performed using 2D-FDTD method where simulation is done through an optical switch. This switch is composed of nonlinear PCRR and T-type waveguide. The dielectric rods used in air is of Indium Phosphide with refractive index of 3.1. Ban...

U-shaped thin-walled concrete bridge beams usually suffer the combined actions of flexure, shear and torsion, but no research about the behavior of U-shaped thin-walled RC beams under combined actions has been reported in literature. Three large specimens of U-shaped thin-walled RC beams were tested under different torque–bending moment ratios (T–M ratios) of 1:5, 1:1 and 1:0 to investigate the...

The present work is concerned with the weak interactions between hydrogen and halogen molecules, i.e., the interactions of pairs H2-X2 with X = F, Cl, Br, which are dominated by dispersion and quadrupole-quadrupole forces. The global minimum of the four-dimensional (4D) coupled cluster with singles and doubles and perturbative triples (CCSD(T)) pair potentials is always a T shaped structure whe...