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...

  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...

Background: Yazd waste stabilization pond facilities consist of three stabilization pond systems, module 1, module 2 and module 3 that AWSP module 1 has started its operation. The existing facilities have had several problems in their operation. The objectives of this research were to evaluate the performance of stabilization ponds in wastewater treatment of the city of Yazd, due to several pro...

background in stable patients with blunt abdominal trauma, accurate diagnosis of visceral injuries is crucial. objectives to determine whether repeating ultrasound exam will increase the sensitivity of focused abdominal sonography for trauma (fast) through revealing additional free intraperitoneal fluid in patients with blunt abdominal trauma. patients and methods we performed a prospective obs...

unsteady hydromagnetic generalised couette flow of a viscous, incompressible and electrically conducting fluid between two horizontal parallel porous plates darcian channel in the presence of a uniform transverse magnetic field taking hall current and ion-slip into account in a rotating system is investigated. an exact solution of the governing equations is obtained by laplace transform techniq...