Análisis del comportamiento a compresión de un laminado [0,90,0,90] de tejido no ondulado mediante un modelo 3D de elementos finitos

VI CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Valencia, 27-29 de junio de 2005.El presente trabajo está dedicado al análisis numérico del comportamiento a compresión de un laminado [0, 90]a de tejido no ondulado o non-crimp fabric (NCF). Para ello se ha realizado un modelo tridimensional de elementos finitos del laminado a nivel mesoscópico en el que se han modelado los constituyentes del material, mazos de fibras y paquetes de resina, como entes homogéneos, sin considerar la microestructura que caracteriza a cada uno de ellos. Los resultados obtenidos con este modelo muestran que el mecanismo de fallo a compresión de un laminado de NCF está asociado a la curvatura que presentan los mazos de fibras en este tipo de materiales compuestos, como consecuencia del curado. En efecto, en la zona en que dicha curvatura es máxima aparecen deformaciones tangenciales de diferente signo cuya diferencia crece a medida que la carga de compresión aplicada aumenta hasta que llega un momento en que el material no es capaz de soportarlo y se produce el fallo.Unión Europea (FALCOM) G4RD-CT- 0069

Report on fisheries mangement in international deep sea water and its biodiversity conservation

It is a repport on the FAO "Analysis and guide for the implementation of international and policy instruments related to deep sea fisheries and biodiversity conservation in ABJN (Areas Beyond National Jurisdiction)” of 27th June 2016

Prehistoria de la matemática y mente moderna : pensamiento matemático y recursividad en el Paleolítico franco-cantábrico

En este artículo, en primer lugar, se repasan de forma general distintos tipos de registros simbólicos realizados por los grupos prehistóricos desde los más remotos y probables orígenes de la mente humana moderna. A continuación, se revisan algunas de las más destacadas piezas de la Prehistoria relacionadas con el registro matemático, destacando la importancia (por cantidad y calidad), no suficientemente valorada, de las piezas de este tipo de la región franco-cantábrica. La información anterior, finalmente, nos da pie a destacar la tremenda importancia en este contexto de cuatro plaquitas de hueso hioides de caballo de la Cueva de Altamira, datadas en el Solutrense Superior (c. 18.500 años). Estas plaquitas, al ser un conjunto coherente de elementos interrelacionados, se proponen aquí como la representación de una recursividad, cualidad ésta que se ha considerado como propia y exclusiva del lenguaje humano

Characterization of fimbriae extracts from porcine enterotoxigenic Escherichia coli strains carrying F6 (987P) antigen

Fimbrial extracts from porcine enterotoxigenic Escherichia coli (ETEC) strains carrying F6 (987P) intestinal colonization factor antigen were obtained using the thermal shock method. The extracts were analyzed by SDSPAGE and immunoblotting using different fimbriae-specific antisera. Two major protein bands with molecular masses of 17.5 and 21.9 kDa were detected. The 21.9-kDa band was identified as the major subunit of F6 fimbrial antigen in strains of serogroups O9 and O141. The 17.5-kDa band was associated with porcine strains of serogroups O9 and O20. [Int Microbiol 2006; 9(4):241-246

A comparative note on the relaxation algorithms for the linear semi-infinite feasibility problem

The problem (LFP) of finding a feasible solution to a given linear semi-infinite system arises in different contexts. This paper provides an empirical comparative study of relaxation algorithms for (LFP). In this study we consider, together with the classical algorithm, implemented with different values of the fixed parameter (the step size), a new relaxation algorithm with random parameter which outperforms the classical one in most test problems whatever fixed parameter is taken. This new algorithm converges geometrically to a feasible solution under mild conditions. The relaxation algorithms under comparison have been implemented using the extended cutting angle method for solving the global optimization subproblems.This research was partially supported by MICINN of Spain, Grant MTM2014-59179-C2-1-P and Sistema Nacional de Investigadores, Mexico

On the Controllability of Parabolic Systems with a Nonlinear Term Involving the State and the Gradient

We present some results concerning the controllability of a quasi-linear parabolic equation (with linear principal part) in a bounded domain of ${\mathbb R}^N$ with Dirichlet boundary conditions. We analyze the controllability problem with distributed controls (supported on a small open subset) and boundary controls (supported on a small part of the boundary). We prove that the system is null and approximately controllable at any time if the nonlinear term $f( y, \nabla y)$ grows slower than $|y| \log^{3/2}(1+ |y| + |\nabla y|) + |\nabla y| \log^{1/2}(1+ |y| + |\nabla y|)$ at infinity (generally, in this case, in the absence of control, blow-up occurs). The proofs use global Carleman estimates, parabolic regularity, and the fixed point method

Spanish Research Report for 1994

13 páginas, 12 tablasPeer reviewe

Greenland Halibut Depth Variations of Catch-per-unit Effort, Length Composition, Mature Proportions and Associated By-catches in Divisions 3LMNO

In this paper we present a review of the geographic and bathimetric patterns of occurrence of the Greenland halibut catches in NAFO Divisions 3LMNO and their incidence on the catch of other stocks, namely cod, American plaice and yellowtail and witch flounders. The Greenland halibut mature proportions at depth in both the commercial catches and the spring Spanish 3NO survey indices are also presented. According to the results of the Spanish fleet, the Greenland halibut fishery does not overlap significantly with either American plaice, yellowtail flounder, skate or cod. By-catches of witch flounder in the Greenland halibut fishery have been very small, at least in 1999. The CPUE analysis indicate that Greenland halibut is best caught in the deepest strata, with catch rates comparatively poor at depths less than 600 m. Besides a sharp change in catchability is observed between 500 – 600 m. The proportion of mature fish in the catches increases with depth attaining a maximum between 1200 – 1600 m. The survey results indicate that most part of the SSB is found at depths beyond 800 m