in this research, the charged system search (css) and enhanced charged system search (ecss) algorithm are used to obtain the optimum design of irregular grillage systems with different spacing and various boundary conditions. the cross-sectional properties of the beams are selected as the design variables and the weight of structure is used as the objective function. the displacement limitation...

An experimental and numerical study of free convection heat transfer from a channel consisting of a vertical sinusoidal wavy surface and a vertical flat plate has been carried out. The vertical wavy surface was maintained at a constant temperature, while the flat plate is adiabatic. A Mach-Zehnder Interferometer was used to determine the local heat transfer coefficients of sinusoidal wavy surfa...

We report total-energy electronic-structure calculations that provide energetics and electronic structures of double-walled carbon nanotubes consisting of semiconducting (n,0) nanotubes. We find that optimum spacing between the walls of the nanotubes is slightly larger than the interlayer spacing of the graphite. We also find that the electronic structures of the double-walled nanotubes with th...

We analyze optical phased arrays with aperiodic pitch and element-to-element spacing greater than one wavelength at channel counts exceeding hundreds of elements. We optimize the spacing between waveguides for highest side-mode suppression providing grating lobe free steering in full visible space while preserving the narrow beamwidth. Optimum waveguide placement strategies are derived and desi...

Vernonia galamensis Cass is a huge potential industrial crop with very high content of vernolic acid in the seed oil. The experiment was carried out to determine the effect of inter- and intra- row spacing on the yield and yield related traits of Vernonia galamensis Cas.The experiment was conducted for two years during 2014-2015 on experimental field of Wondo Genet Agricultural research center,...

In phased array antennas, the number of radiator rows is one of the important factors to minimizing both cost and weight. Therefore, the antenna tilt angles having relation with the element spacing are among the important design parameters. In this paper, the optimum tilt angles for several types of dipole planar arrays are investigated theoretically. To obtain optimum tilt angles, the directiv...

Vernonia galamensis Cass is a huge potential industrial crop with very high content of vernolic acid in the seed oil. The experiment was carried out to determine the effect of inter- and intra- row spacing on the yield and yield related traits of Vernonia galamensis Cas.The experiment was conducted for two years during 2014-2015 on experimental field of Wondo Genet Agricultural research center,...

This paper investigates the optimum dispersion mapping for 40Gbps WDM system. The paper shows the performance of five channel WDM system with the channel spacing of 100GHz (0.8nm) by using non-zero dispersion shifted fiber (NZDSF) and dispersion compensation fiber (DCF). In addition it reveals both pre-compensation and residual dispersion per span can develop the performance. The modulation for...