Leaching of a low-grade lead and zinc oxide ore was studied by an organic reagent, citric acid. The quadratic mathematical models were developed for the relationship among the influential parameters and lead and zinc recoveries. Leaching rate was strongly affected by the interactive effects of factors. It was also found that the quadratic effects of stirring speed and linear<e...

Abstract In this paper, we study some bounds for nonconvex quadratically constrained quadratic programs (QCQPs). We propose two types of QCQPs, and cubic bounds. use affine functions as Lagrange multipliers demonstrate that most semidefinite relaxations can be obtained the dual a bound. addition, by changing ground set. For bounds, in addition to employ functions. provide comparison between pro...