Method for optimization of statically determined articulated structures

Se ha desarrollado un algoritrr)o de programación matemática para el dimensionamiento óptimo de estructuras articuladas isostáticas. El algoritmo propuesto se caracteriza por: a) No requerir que la función objetivo o las ecuaciones de restricción sean derivables. b) Utilizan métodos de optimización unidimensionales para pasar de una solución dada a otra mejor, c) Introducir procedimientos aleatorios para obtener información que conduce a una solución mejor. Estas características lo hacen especialmente indicado para funciones no explícitas, costosas en su evaluación y con gran cantidad de mínimos relativos. Se ilustra el método con dos ejemplos de diseño óptimo de estructuras articuladas estáticamente determinadasAn algorithm of mathematical programmation for the optimum dis'fgn of iso-static articúlate structures has been developed. The characteristics of the proposed algorithm are: a) It not requires that the objective function or the restriction equations be derivable. b) They use unidimensional methods of unidimensional optimization ío pass over from a g/Ven so/ut/on to a better one. c) To introduce contingent procedures to obtain Information which leads to a better solution. Those characteristics make it specially recommended for non-explicit functions, costly in its evaluation with a great deal of relative mínimums. The method is explained by two exampies of óptima! design of statiscally determined articulated structure

Soil organic carbon along an altitudinal gradient in the Despeñaperros Natural Park, southern Spain

Soil organic carbon (SOC) is extremely important in the global carbon (C) cycle as C sequestration in non-disturbed soil ecosystems can be a C sink and mitigate greenhouse-gas-driven climate change. Soil organic carbon changes in space and time are relevant to understand the soil system and its role in the C cycle. This is why the influence of topographic position on SOC should be studied. Seven topographic positions from a toposequence between 607 and 1168 m were analyzed in the Despeñaperros Natural Park (Jaén, SW Spain). Depending on soil depth, one to three control sections (0–25, 25–50 and 75 cm) were sampled at each site. The SOC content in studied soils was below 30 g kg⁻¹ and strongly decreases with depth. These results were related to the gravel content and to the bulk density. The SOC content from the topsoil (0–25 cm) varied largely through the altitudinal gradient ranging between 27.3 and 39.9 g kg⁻¹. The SOC stock (SOCS) varied between 53.8 and 158.0 Mg ha⁻¹ in the studied area, which had been clearly conditioned by the topographic position. Therefore, results suggest that elevation should be included in SOCS models and estimations at local and regional scales

Un método de optimización de estructuras articuladas estáticamente determinadas

An algorithm of mathematical programmation for the optimum disign of iso-static articulate structures has been developed. The characteristics of the proposed algorithm are: a) It not requires that the objective function or the restriction equations be derivable. b) They use unidimensional methods of unidimensional optimization to pass over from a given solution to a better one. c) To introduce contingent procedures to obtain Information which leads to a better solution. Those characteristics make it specially recommended for non-explicit functions, costly in its evaluation with a great deal of relative minimums. The method is explained by two examples of optimal design of statiscally determined articulated structures.<br><br>Se ha desarrollado un algoritmo de programación matemática para el dimensionamiento óptimo de estructuras articuladas isostáticas. El algoritmo propuesto se caracteriza por: a) No requerir que la función objetivo o las ecuaciones de restricción sean derivables. b) Utilizan métodos de optimización unidimensionales para pasar de una solución dada a otra mejor, c) Introducir procedimientos aleatorios para obtener información que conduce a una solución mejor. Estas características lo hacen especialmente indicado para funciones no explícitas, costosas en su evaluación y con gran cantidad de mínimos relativos. Se ilustra el método con dos ejemplos de diseño óptimo de estructuras articuladas estáticamente determinadas