a module m is called epi-retractable if every submodule of m is a homomorphic image of m. dually, a module m is called co-epi-retractable if it contains a copy of each of its factor modules. in special case, a ring r is called co-pli (resp. co-pri) if rr (resp. rr) is co-epi-retractable. it is proved that if r is a left principal right duo ring, then every left ideal of r is an epi-retractable ...

development management is one of the newest fields of social sciences brought about by multidisciplinary approaches. the roots of these approaches are traced in the writings of adorno, horkheimer, marcuse and habermas, pioneers of the frankfurt school. as an interdisciplinary field, mostly applied, development management is obviously the fruit of civil society, a society that values participato...

A full solution-based method is reported to fabricate multilayer thin film stacks for structural color applications. This in contrast the conventional fabrication methods that require high vacuum processes such as physical vapor deposition and magnetron sputtering, which significantly limits their practical use due cost long processing time. Copper/silicon dioxide/copper (Cu/SiO2/Cu) copper/tit...

  Abstract:   The aims of this research were to investigate the effects of semisolid metal (SSM) processing parameters (i.e., shear rates –times – temperatures combinations) on the primary solidification products and isothermal holding duration, subsequent to cessation of stirring on the secondary solidification of Al-Si (A356) alloy.   The dendrite fragmentation was found to be the governing m...