Bounds on the dragging rate and on the rotational mass-energy in slowly and differentially rotating relativistic stars

For relativistic stars rotating slowly and differentially with a positive angular velocity, some properties in relation to the positiveness of the rate of rotational dragging and of the angular momentum density are derived. Also, a new proof for the bounds on the rotational mass-energy is given.Comment: 23 pages, latex. Submitted to J. Math. Phy

SFX, OpenURL y otras mejoras en las Bases de datos CSIC

Sección: Noticias. Noticias internas2006 está siendo un buen año para las Bases de datos CSIC.Uno de sus productores, el Centro de Información y Documentación Científica (CINDOC), en colaboración con el Centro Técnico de Informática (CTI), acometió un plan de mejora y renovación que cristalizó en su primera fase con la puesta en marcha a finales de 2005 de un nuevo interfaz para su consulta en línea. El objetivo de tal plan, necesario por otra parte, era dotar a la pasarela de un diseño más actual y acorde con la imagen corporativa del CSIC, además de modernizarla técnicamente.N

Stability of nanoscale secondary phases in an oxide dispersion strengthened Fe-12Cr alloy

Transmission electron microscopy and atom-probe tomography were used to characterize on a near-atomic scale the microstructure and oxide and carbide phases that form during thermo-mechanical treatments of a model oxide dispersion strengthened Fe-12 wt.% Cr-0.4 wt.% Y₂O₃ alloy. It was found that some of the Y-rich nanoparticles retained their initial crystallographic structure but developed a Cr-enriched shell, while others evolved into ternary oxide phases during the initial processing. The Y- and Cr-rich oxide phases formed remained stable after annealing at 1023 K for 96 h. However, the number of Cr-rich carbides appeared to increase, inducing Cr depletion in the matrix.the FP6 Euratom Research and Training Programme on Nuclear Energy (VdC), The Engineering and Physical Sciences Research Council (SLP) and The Royal Society (EAM). The Comunidad de Madrid, through the ESTRUMATCM (MAT-77) programme, and the use of the Chemical Database Service at DaresburyPublicad

Procesos participativos de gestión para la sostenibilidad del desarrollo rural. El caso CETS (Carta Europea de Desarrollo Sostenible) en el Delta del Ebro, España

El desarrollo rural se asocia habitualmente tanto a los recursos endógenos de cada territorio como a los procedimientos que se articulan para movilizarlos. Recientemente, la sostenibilidad territorial se ha incorporado como elemento intrínsecamente asociado al despliegue del potencial del mundo rural. Sin embargo, ciertas actividades como el turismo han planteado una dicotomía entre la vertiente económica y la preservación medioambiental del territorio. Este trabajo enfatiza la articulación de partenariados en los procesos de gestión como estrategia clave para el desarrollo rural sostenible. A través del análisis del proceso de la Carta Europa de Turismo Sostenible (CETS) en el Delta del Ebro (España), se identifican los elementos de gobernanza participativa que facilitan el consenso y la movilización de recursos para el desarrollo sostenible, dotando de este modo de mayor legitimidad a las actuaciones

Influencia de la composición y microestructura sobre las propiedades mecánicas de aleaciones de wolframio

Comunicaciones presentadas en: XXVI Encuentro del Grupo Español de Fractura, Santander, 25 marzo 2009.En esta investigación se estudia la influencia de la microestructura en el comportamiento mecánico del wolframio puro y aleaciones con contenidos de 0.5% de Y₂O₃ y 4% de Ti, todos ellos obtenidos mediante HIP. Con el fin de correlacionar el comportamiento macroscópico con los parámetros microestructurales, se ha analizado mediante microscopía óptica y electrónica de barrido, la microestructura y las superficies de fractura muestras ensayadas en flexión en tres puntos a diferentes temperaturas (entre 25 y 1000 °C). La medida del tamaño de grano de las muestras se ha realizado, de acuerdo con la norma ASTM E112, mediante un programa de análisis de imagen. Los resultados muestran que la adición de titanio al wolframio mejora las propiedades del material al obtenerse éste exento de porosidad. La formación de una solución sólida, y la estructura de tamaño de grano más fina, aumentan la resistencia mecánica del material hasta temperaturas superiores a 600 °C. Por otra parte la adición de itria comportamiento mecánico del wolframio puro a altas temperaturas, evitando la oxidación, pero no modifica sustancialmente el tamaño de grano obtenido bajo las condiciones de fabricación, debido a la formación de fases eutécticas.In this research the influence of the microstructure in the mechanical behaviour of pure tungsten and its alloys with 0.5% of yttrium oxide and 4% titanium contents, all of them manufactured by HIP, is considered. The microstructure and fracture surfaces of the samples tested in three points bending at different temperatures (between 25 and 1000 ºC) are studied by optical microscopy and SEM, in order to relation the macroscopic behaviour with the microstructural analyzed parameters. The size grain has been measured according to ASTM E112 code, using a image analysis software. The results show that the addition of titanium to the pure tungsten lets manufacture a material without pores improving its mechanical properties. The solid solution, and refined grain structure obtained in these materials, raised the mechanical behaviour up to 600 ºC. The yttrium oxide addition improved the mechanical properties at high temperatures respect to pure tungsten, and avoids oxidation. Nevertheless, this does not modify substantially the grain size obtained in the manufacturing conditions due to the eutectic constituent formation.Proyecto financiado por el Ministerio de Ciencia e Innovación en virtud de los proyectos MAT2006‐13005‐C03‐02, MAT2007‐29278‐E, y CSD00C-06-14102, por la Comunidad de Madrid a través del programa ESTRUMAT-CM (S-0505/MAT/0077) y por la Asociación EURATOM/CIEMAT/EFDA a través del contrato TW6-TTMA-002-EFDA.Publicad

Microstructure and mechanical behavior of ODS and non-ODS Fe-14Cr model alloys produced by spark plasma sintering

In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparti-cles. Elemental powders of Fe and Cr, and nanosized Y₂O₃ powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14% Cr–0.3%Y₂O₃ (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metal-lurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS tech-nique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dis-persion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS.This investigation was supported by the Ministry of Science and Innovation of Spain (Project No. ENE 2008-06403-C06-04), the Comunidad de Madrid through the program ESTRUMAT-CM(Grant No. S0505/MAT/0077), and the European Commission through the European Fusion Development Agreement (Contract No. 09-240), the IP3 FP6 ESTEEM project (Contract No. 026019) and the Fusion Energy Materials Science (FEMaS) FP7 coordination action.Publicad

Local freedom in the gravitational field revisited

Maartens {\it et al.}\@ gave a covariant characterization, in a 1+3 formalism based on a perfect fluid's velocity, of the parts of the first derivatives of the curvature tensor in general relativity which are ``locally free'', i.e. not pointwise determined by the fluid energy momentum and its derivative. The full decomposition of independent curvature derivative components given in earlier work on the spinor approach to the equivalence problem enables analogous general results to be stated for any order: the independent matter terms can also be characterized. Explicit relations between the two sets of results are obtained. The 24 Maartens {\it et al.} locally free data are shown to correspond to the $\nabla \Psi$ quantities in the spinor approach, and the fluid terms are similarly related to the remaining 16 independent quantities in the first derivatives of the curvature.Comment: LaTeX. 13 pp. To be submitted to Class. Quant. Gra

Algorithmic Debugging of Real-World Haskell Programs: Deriving Dependencies from the Cost Centre Stack

Existing algorithmic debuggers for Haskell require a transformation of all modules in a program, even libraries that the user does not want to debug and which may use language features not supported by the debugger. This is a pity, because a promising ap- proach to debugging is therefore not applicable to many real-world programs. We use the cost centre stack from the Glasgow Haskell Compiler profiling environment together with runtime value observations as provided by the Haskell Object Observation Debugger (HOOD) to collect enough information for algorithmic debugging. Program annotations are in suspected modules only. With this technique algorithmic debugging is applicable to a much larger set of Haskell programs. This demonstrates that for functional languages in general a simple stack trace extension is useful to support tasks such as profiling and debugging

Characterization of novel W alloys produced by HIP

Proceedings of: The Thirteenth International Conference on Fusion Reactor, Nice (France), 10–14 December 2007.W and W alloys containing 0.5 wt% Y₂O₃, x wt% Ti and (x wt% Ti + 0.5 wt% Y₂O₃) have been prepared, x 2 or 4. Elemental powders were blended or ball milled, canned, degassed and finally consolidated by a two stage HIP process under a pressure of 195 MPa. It is found that Ti addition favours the densification attaining a fully dense material. XRD, SEM and EDX analyses of the material with Ti addition reveal the formation of a microstructure consisting of tungsten particles embedded in a W Ti matrix. The microhardness of these materials increased noticeably with the titanium content.Dirección General de Investigación (Ministry of Education of Spain, Contract MAT2004 1819), the Dirección General de Universidades (Comunidad de Madrid) through the program of ESTRUMAT CM (Grant S 0505/MAT/0077) and EURATOM/CIEMAT Association through Contract 07/006.Publicad

Interculturality and Teacher Education. A Study from Pre-service Teachers’ Perspective

Due to the multicultural nature of society and the failure of some of the educational models adopted to respond to cultural diversity, there is a need to pay greater attention to teachers’ training. This study examines Teacher Education students’ beliefs about cultural diversity and their relationship with pre-service teacher training as key aspects in designing intercultural teacher training proposals and improving educational practice. This quantitative, descriptive study was carried out with 1464 participants enrolled in teacher training programs. The results show that future teachers have positive beliefs about cultural diversity in general terms, but their positions diverge when dealing with specific aspects and transferring them to professional practice. These beliefs vary depending on the year group, with students who are finishing their training process having more intercultural beliefs