Rapid prototyping (RP) methods are used for production easily and quickly of a scale model of a physical part or assembly. Gas metal arc welding (GMAW) is a widespread process used for rapid prototyping of metallic parts. In this process, in order to obtain a desired welding geometry, it is very important to predict the weld bead geometry based on the input process parameters, which are voltage...

One of the most important challenges in the development of urban railways network is the effects of railway vibrations on human and adjacent structures. Although various investigations into the sources of railway vibrations have been conducted, very few research works have been reported on the influences of track geometry parameters on the level of vibrations. This is addressed in this resea...

In this study, we theoretically investigated Methyl hydrazinecarbodithioate by quantum chemical calculations for geometry optimization, vibration frequencies, and electronic structure parameters. The geometry optimization by DFT, ab initio MP2 method and the frequency calculation by DFT method was performed at the highest available Pople style 6-311G++(3df,3pd) basis set level. The semi-emp...

There are different approaches for diffractive photoproduction of charmonia. Recently, a new approach is proposed, in which charm quarks are taken as heavy quarks and the nonperturbative effect related to charmonia can be handled with nonrelativistic QCD. The interaction between the cc̄ pair and the initial hadron is through exchange of soft gluons. The exchange of soft gluons can be studied wit...

Using the even-odd mode anafysis of four-port networks with double symmetry, the scattering parameters of the microstrip-slot coupler are derived from the evenand odd-mode parameters of the coupler cross section. The uncompensated coupler and the coupler compensated by extending tbe slot fines are treated and desigo specifications are given covering the compensation slot lines. A comparison wit...

The workspace topologies of a family of 3-revolute (3R) positioning manipulators are enumerated. The workspace is characterized in a half-cross section by the singular curves. The workspace topology is defined by the number of cusps that appear on these singular curves. The design parameters space is shown to be divided into five domains where all manipulators have the same number of cusps. Eac...