Sharif Digital Repository

This paper applies the method of decomposition of wavefronts to ray tube tracing model. Energy ray tubes which are emitted from the source are modeled by three rays and the method of decomposition of wavefronts iteratively improves the accuracy of ray tracing. Comparison with applying the method of decomposition of wavefronts to conventional ray tracing is made afterwards. It is observed that by applying the method of decomposition of wavefronts to ray tube model, the accuracy of ray tracing can be improved much more efficiently and the simulation time decreases to almost a half. ©2009 IEEE  

The network structure of styrene-butadiene rubber (SBR) in the presence of carbon black (CB) with two different structures and multi-walled carbon nanotubes (MWCNTs) was investigated. Swelling behaviour, tensile properties at various strain rates and cure kinetics were characterized. Experimental data were analysed using the Flory-Rehner model as well as the tube model theory. It is found that the network structure of CB-filled SBR follows a three-phase composite model including rigid particles, semi-rigid bound rubber and matrix rubber. This bound rubber is postulated to be critical for the mechanical and deformational properties, development of crosslinking density in matrix rubber and... 

The aim of this work is to produce two layered thin-walled Cu/Al composite tube by the spin-bonding process. The process is utilized to bond the aluminum tube into the copper one at thickness reductions of 20-60% and process temperatures of 25°C, 130°C, and 230°C. The bond strength is measured by T-peeling test, and the bond interfaces are examined by metallography and scanning electron microscopy (SEM). The results show that after a threshold thickness reduction of about 30%, the bond strength increased with the amount of deformation. SEM fractography of the peel surfaces confirms that the copper oxide film is broken in a shear manner during deformation. Severe shear strains applied during...