Some connections between constructive real algebraic geometry and constrained optimization are exploited. We show how the problem of determining the projection of a real-algebraic variety on a certain axis is equivalent to a problem in nonlinear programming. As an application, Grr obner bases are used to deal with an optimization problem arising in the theory of local Lyapunov functions. The pr...

biodiesel fuel, which is produced by transesterification reaction between alcohol and vegetable oil/animal fat is proposed as a clean alternative to petro diesel fuel. today, one of the new technologies to produce biodiesel is using ultrasonic energy that makes production faster, with improved quality and less expensive. various factors that affect the design of ultrasonic reactors are ratio of...

Multilateral wells have been increasingly used in recent years by different industries such as the oil- and gas industry (incl. coal-bed methane (CBM)) geothermal energy production. The common purpose of these oil partially is to achieve a higher production rate per well without increasing hydraulic gradient significantly. In systems ultimate objective improve heat extraction performance enhanc...

Abstract In order to improve the working capacity and life of bearing units, dimensional analysis inner geometry a cylindrical radial was carried out. The assembly component, composed by outer diameter dimensions raceway race, race two diameters rollers, considered as dimension chain. It is recommended, in reduce wear friction losses, produce diametrical roller according fifth accuracy degree. ...

The study proposes a technique for optimizing trihedral lattice tower structures from the condition of maximum critical load. Towers with cross section elements in form round pipes are considered. load is represented by horizontal concentrated force at upper end tower, simulating operation wind turbine. A constraint on constancy mass structure introduced. variable parameters width which varies ...