Modal decomposition method for BWR stability analysis using Alpha-modes

[EN] In-phase and out-of-phase oscillations have been observed in BWR reactors. To improve the safety of these reactors it is necessary to detect in a reliable way these oscillations from the neutronic signals. In this paper, a methodology to decompose the neutronic signals in its modal amplitudes is proposed. Usually, to compute this decomposition the Lambda eigenfunctions are used as expansion functions and their adjoint modes are used as weight factors. Different approaches using the Alpha modes are investigated to obtain the LPRM signals modal decomposition for a BWR unstability event. The calculation of Alpha eigenmodes is reviewed and the oscillation parameters for the modal decomposition of the neutronic signals from Ringhals NPP have been calculated.This work has been partially supported by the Spanish Ministerio de Educación y Ciencia under Project ENE2011-22823.Verdú Martín, GJ.; Ginestar Peiro, D. (2014). Modal decomposition method for BWR stability analysis using Alpha-modes. Annals of Nuclear Energy. 67:31-40. https://doi.org/10.1016/j.anucene.2013.07.035S31406

Updating the Lambda modes of a nuclear power reactor

[EN] Starting from a steady state configuration of a nuclear power reactor some situations arise in which the reactor configuration is perturbed. The Lambda modes are eigenfunctions associated with a given configuration of the reactor, which have successfully been used to describe unstable events in BWRs. To compute several eigenvalues and its corresponding eigenfunctions for a nuclear reactor is quite expensive from the computational point of view. Krylov subspace methods are efficient methods to compute the dominant Lambda modes associated with a given configuration of the reactor, but if the Lambda modes have to be computed for different perturbed configurations of the reactor more efficient methods can be used. In this paper, different methods for the updating Lambda modes problem will be proposed and compared by computing the dominant Lambda modes of different configurations associated with a Boron injection transient in a typical BWR reactor. (C) 2010 Elsevier Ltd. All rights reserved.This work has been partially supported by the Spanish Ministerio de Educacion y Ciencia under projects ENE2008-02669 and MTM2007-64477-AR07, the Generalitat Valenciana under project ACOMP/2009/058, and the Universidad Politecnica de Valencia under project PAID-05-09-4285.González Pintor, S.; Ginestar Peiro, D.; Verdú Martín, GJ. (2011). Updating the Lambda modes of a nuclear power reactor. Mathematical and Computer Modelling. 54(7):1796-1801. https://doi.org/10.1016/j.mcm.2010.12.013S1796180154

Calculation of electrostatic fields using quasi-Green's functions: application to the hybrid Penning trap.

Penning traps offer unique possibilities for storing, manipulating and investigating charged particles with high sensitivity and accuracy. The widespread applications of Penning traps in physics and chemistry comprise e.g. mass spectrometry, laser spectroscopy, measurements of electronic and nuclear magnetic moments, chemical sample analysis and reaction studies. We have developed a method, based on the Green's function approach, which allows for the analytical calculation of the electrostatic properties of a Penning trap with arbitrary electrodes. The ansatz features an extension of Dirichlet's problem to nontrivial geometries and leads to an analytical solution of the Laplace equation. As an example we discuss the toroidal hybrid Penning trap designed for our planned measurements of the magnetic moment of the (anti)proton. As in the case of cylindrical Penning traps, it is possible to optimize the properties of the electric trapping fields, which is mandatory for high-precision experiments with single charged particles. Of particular interest are the anharmonicity compensation, orthogonality and optimum adjustment of frequency shifts by the continuous SternGerlach effect in a quantum jump spectrometer. The mathematical formalism developed goes beyond the mere design of novel Penning traps and has potential applications in other fields of physics and engineering

Soil shapes community structure through fire

7 páginas, 2 figuras, 2 tablas.Recurrent wildWres constitute a major selecting force in shaping the structure of plant communities. At the regional scale, Wre favours phenotypic and phylogenetic clustering in Mediterranean woody plant communities. Nevertheless, the incidence of Wre within a Wre-prone region may present strong variations at the local, landscape scale. This study tests the prediction that woody communities on acid, nutrient-poor soils should exhibit more pronounced phenotypic and phylogenetic clustering patterns than woody communities on fertile soils, as a consequence of their higher Xammability and, hence, presumably higher propensity to recurrent Wre. Results conWrm the predictions and show that habitat Wltering driven by Wre may be detected even in local communities from an already Wre-Wltered regional Xora. They also provide a new perspective from which to consider a preponderant role of Wre as a key evolutionary force in acid, infertile Mediterranean heathlands.This work has been partially supported by projects VAMPIRO (CGL2008-05289-C02-01/BOS) and PERSIST (CGL2006-07126/BOS), Wnanced by the Spanish Ministerio de Ciencia e Innovación, and project P07-RNM-02869, Wnanced by the Junta de Andalucía regional government (Spain). Fieldwork was carried out under permission and complied with legal requirements of the Andalusian regional government.Peer reviewe

Factores psicosociales influyentes en la ocurrencia de accidentes laborales

El objetivo del trabajo es la presentación de un modelo de predicción de la siniestralidad laboral basado en datos empíricos en un conjunto de variables susceptibles de intervención. El método empleado es un diseño transversal y correlacional, en el que a partir de una muestra representativa de más de 500 trabajadores de diferentes sectores de actividad de la provincia de Valencia, se cuantifica la importancia relativa de cada uno de los aspectos definidos como relevantes para predecir la ocurrencia de accidentes. El uso metodológico de modelos de ecuaciones estructurales permite la consideración simultánea de un gran número de variables, junto con un adecuado control estadístico, reflejando así con mayor fidelidad la problemática de la siniestralidad laboral. Los resultados muestran el impacto de la variables organizacionales y los riesgos sobre variables del trabajador, la importancia de éstas en la predicción de accidentes, junto con su papel mediador en los efectos de las variables organizacionales (clima de seguridad, formación en seguridad, sobrecarga de trabajo, etc.) sobre la ocurrencia de accidentes laborales. La conclusión es que los aspectos psicosociales son claves en la explicación de los accidentes laborales y abren vías para una intervención efica

Location and Adoption of ICT Innovations in the agri-food industry

This is an author's accepted manuscript of an article published in: “Applied Economics Letters"; Volume 21, Issue 6, 2014; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1080/13504851.2013.864032[EN] This article identifies the web technologies adoption pattern of agri-food industries considering a set of characteristics which include location, economic performance and previous history of adopting innovations. Our main results highlight that, together with certain firm characteristics, rural locations act as an accelerator for the adoption of web technology, compared to the slower adoption rate in urban areas.The authors are grateful for the support received from the Universitat Politècnica de València, (PAID-06-12)Doménech I De Soria, J.; Martinez Gómez, VD.; Mas Verdú, F. (2014). Location and Adoption of ICT Innovations in the agri-food industry. Applied Economics Letters. 21(6):421-424. https://doi.org/10.1080/13504851.2013.864032S42142421

Effects of reduced and conventional tillage on weed communities: Results of a long-term experiment in Southwestern Spain [Efeito do cultivo mínimo e plantio convencional em comunidades de plantas daninhas: Resultados de um experimento de longo prazo no sudoeste da espanha]

An important drawback in adopting minimum tillage (MT) and notillage (NT) techniques is the frequently observed weed shift promoting adapted species and achieving poorer weed control. These changes can be detected best with long-term experiments, and results might differ depending on soil characteristics and the local flora. The objectives of this work were to evaluate the effect of reduced tillage on weed seed distribution in the soil profile and to identify possible consequences on weed diversity on a long-term experiment maintained during 24 years in Seville (Spain) with three tillage systems: NT, MT and conventional tillage (CT) including moldboard plow on a vertisol. For this purpose, soil seedbanks at 0-8 cm and 8-16 cm depths were enumerated in autumn 2005 and in-field emerged plants in autumn 2005 and winter 2006. Shannon diversity index (H) and evenness (J’) were calculated for seedbank and aboveground weed communities. Total weed seed density was highest for NT and lowest for CT. Some big-seeded species, such as Chrozophora tinctorea L., showed highest seed density in CT. NT increased the relative density of Amaranthus blitoides S. Watson seeds in the seedbank and the abundance of emerged plants of Malva parviflora L., Anagallis arvensis L. and Picris echioides L. Overall, MT led to a less diverse seedbank in the 0-8 cm depth of soil than CT. The frequent drought-induced deep fractures in the expandable clay soil caused natural tillage, which probably resulted in fewer differences in weed seed and seedling densities among tillage treatments compared to what might be expected in other soil types

A System to Generate SignWriting for Video Tracks Enhancing Accessibility of Deaf People

Video content has increased much on the Internet during last years. In spite of the efforts of different organizations and governments to increase the accessibility of websites, most multimedia content on the Internet is not accessible. This paper describes a system that contributes to make multimedia content more accessible on the Web, by automatically translating subtitles in oral language to SignWriting, a way of writing Sign Language. This system extends the functionality of a general web platform that can provide accessible web content for different needs. This platform has a core component that automatically converts any web page to a web page compliant with level AA of WAI guidelines. Around this core component, different adapters complete the conversion according to the needs of specific users. One adapter is the Deaf People Accessibility Adapter, which provides accessible web content for the Deaf, based on SignWritting. Functionality of this adapter has been extended with the video subtitle translator system. A first prototype of this system has been tested through different methods including usability and accessibility tests and results show that this tool can enhance the accessibility of video content available on the Web for Deaf people

Evaluation of the self-energy correction to the g-factor of S states in H-like ions

A detailed description of the numerical procedure is presented for the evaluation of the one-loop self-energy correction to the $g$-factor of an electron in the $1s$ and $2s$ states in H-like ions to all orders in $Z\alpha$.Comment: Final version, December 30, 200

An efficient CDMA decoder for correlated information sources

We consider the detection of correlated information sources in the ubiquitous Code-Division Multiple-Access (CDMA) scheme. We propose a message-passing based scheme for detecting correlated sources directly, with no need for source coding. The detection is done simultaneously over a block of transmitted binary symbols (word). Simulation results are provided demonstrating a substantial improvement in bit-error-rate in comparison with the unmodified detector and the alternative of source compression. The robustness of the error-performance improvement is shown under practical model settings, including wrong estimation of the generating Markov transition matrix and finite-length spreading codes.Comment: 11 page