Los niveles glauconíticos de la Formación Salamanca, Chubut : su efectividad agronómica como fuente alternativa de fertilizante potásico

391-398The Maastrichtian-Early Palaeocene Salamanca Formation and equivalent marine sequences show several glaucony levels, which could be used as a source of potassium and could partially replace current fertilizer requirements met from import. First agronomic assays are shown comparing the efficiency of greensands (GL) with a traditional potassium fertilizer (KCl). Prospection and sampling took place in the heads of Rio Chico to east of Lago Colhué Huapi, Chubut, where glauconitic levels thickness reach to 20m. This research was separated in phases: phase 1, prospection, sampling, and sedimentological and chemical routine analyses, phase 2a, concentration and ore treatment assays, and phase 2b, agronomic assays. This last phase, was done in culture chamber, with 125 um and 250 um fractions (2,85 and 2,82 percent K 2O respectively) and KCl. Varying the dose, seven treatments were completed. In successive harvests (four in total) was observed that GL1 and GL2 (125), did not present a significantly differential behavior with the control. Both treatments of GL 250 um showed major accumulated biomass, overcoming the control in 44 and 60 percent respectively. As conclusion, better results were obtained by 250 um overcoming even to the KCl fertilization. Probably the major participation of K feldspars in the 125 um and fast leaching of K in this fraction during successive irrigations of soil would originate the minor observed yield. The great areal extension of the Salamanca Formation and the continuity of the glauconitic levels encourage continuing the evaluation as fertilizer or amendment

Los niveles glauconíticos de la Formación Salamanca, Chubut : su efectividad agronómica como fuente alternativa de fertilizante potásico

391-398The Maastrichtian-Early Palaeocene Salamanca Formation and equivalent marine sequences show several glaucony levels, which could be used as a source of potassium and could partially replace current fertilizer requirements met from import. First agronomic assays are shown comparing the efficiency of greensands (GL) with a traditional potassium fertilizer (KCl). Prospection and sampling took place in the heads of Rio Chico to east of Lago Colhué Huapi, Chubut, where glauconitic levels thickness reach to 20m. This research was separated in phases: phase 1, prospection, sampling, and sedimentological and chemical routine analyses, phase 2a, concentration and ore treatment assays, and phase 2b, agronomic assays. This last phase, was done in culture chamber, with 125 um and 250 um fractions (2,85 and 2,82 percent K 2O respectively) and KCl. Varying the dose, seven treatments were completed. In successive harvests (four in total) was observed that GL1 and GL2 (125), did not present a significantly differential behavior with the control. Both treatments of GL 250 um showed major accumulated biomass, overcoming the control in 44 and 60 percent respectively. As conclusion, better results were obtained by 250 um overcoming even to the KCl fertilization. Probably the major participation of K feldspars in the 125 um and fast leaching of K in this fraction during successive irrigations of soil would originate the minor observed yield. The great areal extension of the Salamanca Formation and the continuity of the glauconitic levels encourage continuing the evaluation as fertilizer or amendment

Implementation of a standard stream-upwind stabilization scheme in the element-free Galerkin based solution of advection-dominated heat transfer problems during solidification in direct chill casting processes

The present work has been conducted in order to propose an alternative solution for the heat transfer problem involved in direct-chill casting (DCC)processes, employing the element-free Galerkin (EFG)method. The internal energy balance has been solved on the basis of this global weak formulation under an Eulerian description. The EFG formulation has been adapted to a three-dimensional steady thermal problem on an aluminum alloy slab. Additionally, the advection dominated problem involved in the casting direction during the liquid-solid phase change has been stabilized by extending adequately the implementation of the stream upwind Petrov?Galerkin (SUPG)scheme to the EFG formulation. A detailed explanation concerning the suitable numerical procedure to achieve such an extension, has also been provided. The feasibility and reliability of this novel approach has been depicted by comparison with both finite element method (FEM)and finite volume method (FVM)based solutions. The results have demonstrated that a proper extension of the SUPG scheme to the EFG method allows the achievement of stable numerical solutions, when predicting the three-dimensional temperature distribution during the phase-change heat transfer phenomena involved in slab DCC processes.Fil: Álvarez Hostos, Juan Carlos. Universidad Central de Venezuela; Venezuela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Bencomo, Alfonso Daniel. Universidad Central de Venezuela; VenezuelaFil: Puchi-Cabrera, Eli S.. Universite Des Sciences Et Technologies de Lille; FranciaFil: Fachinotti, Victor Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Tourn, Benjamin Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Salzar Bove, Joselynne Carolina. Universidad Central de Venezuela; Venezuel