Caracterización de yeso reciclado de calidad y placa de yeso laminado con contenido reciclado maximizado

The quality of secondary materials is imperative to promote a circular economy. In order to improve the way in which the quality of recycled gypsum is assessed, European guidelines on recycled gypsum (RG) quality criteria have been outlined in the framework of the Life+ Gypsum to Gypsum (GtoG) project. Such GtoG guidelines, along with the European Standard on gypsum plasterboard EN 520, provided the basis for this study. During the GtoG project, gypsum recycling and plasterboard manufacturing processes were monitored by testing the gypsum feedstock and the plasterboard produced. The aim of this paper is to discuss the results obtained on relevant parameters that characterize gypsum as a secondary raw material, as well as the resulting product. The minimum requirements were fulfilled by 56% of the RG samples and 86% of the plasterboard with increased RG.La calidad de las materias primas secundarias es fundamental para promover una economía circular. En el marco del proyecto Life+ Gypsum to Gypsum (GtoG), y con el objeto de mejorar el análisis de la calidad del yeso reciclado, se han desarrollado orientaciones en cuanto a los criterios de calidad del material. Estas directrices voluntarias, junto a la norma europea EN 520, son la base del presente trabajo. Los procesos de reciclaje y fabricación se monitorizaron durante el proyecto GtoG, mediante el ensayo de materias primas y placas de yeso laminado. El objetivo del presente artículo es discutir las propiedades del yeso como materia prima secundaria, así como del producto obtenido. Un 56% de las muestras de RG y un 86% de las placas con aumento de contenido de RG cumplieron los requisitos mínimos establecidos

Sintomatología externalizante y rendimiento académico

Este estudio tiene dos objetivos principales; en primer lugar, definir en qué medida el rendimiento académico está relacionado con la presencia de sintomatología externalizante y, por último, ofrecer cifras de prevalencia de dicha sintomatología en una muestra comunitaria. Se utilizó como instrumento el Young Self Report (YSR; Achenbach y Edelbrock, 1987) que evalúa, entre otros aspectos, el comportamiento agresivo y la ruptura de normas. La muestra estuvo constituida por 87 niños y niñas de entre 10 y 12 años, de colegios públicos de la provincia de Albacete. Los resultados arrojaron cifras de prevalencia de sintomatología externalizante en torno al 3% y, además mostraron diferencias significativas en cuanto a la presencia de esta sintomatología en función del rendimiento académico. La implicación más importante que se deriva de estos resultados es que las escuelas deben contar con suficientes recursos para la identificación temprana y el tratamiento de la sintomatología externalizante, dada su implicación en el rendimiento académico y en el clima del aula.This study has two main objectives; firstly, to define the extent to which academic achievement is related to the presence of externalizing symptoms and, secondly, to provide prevalence figures of such symptoms in a community sample. Youth Self Report (YSR; Achenbach and Edelbrock, 1987) was used as a tool which evaluates, among other things, aggressive behaviour and the violation of rules. The sample comprised 87 children between the ages of 10 and 12 years in state schools in Albacete province. The results showed prevalence figures of about 3% and also significant differences in the presence of externalizing symptoms according to academic achievement. The most important implication derived from these results, is that schools must have adequate resources for early identification and treatment of externalizing symptoms, given their influence on academic achievement and the classroom climate

Neutron Fermi Liquids under the presence of a strong magnetic field with effective nuclear forces

Landau's Fermi Liquid parameters are calculated for non-superfluid pure neutron matter in the presence of a strong magnetic field at zero temperature. The particle-hole interactions in the system, where a net magnetization may be present, are characterized by these parameters in the framework of a multipolar formalism. We use either zero- or finite-range effective nuclear forces to describe the nuclear interaction. Using the obtained Fermi Liquid parameters, the effect of a strong magnetic field on some bulk magnitudes such as isothermal compressibility and spin susceptibility is also investigated.Comment: 20 pages, 10 figure

Monte Carlo simulation of damage and amorphization induced by swift-ion irradiation in LiNbO3

This paper presents a Monte Carlo (MC) simulation tool which is applied to describe the ion beam induced damage generated by electronic excitation in LiNbO3. Based on a previously published thermal spike based analytical model, the MC technique allows for a more flexible and accurate treatment of the problem. A main advantage of this approach with respect to the analytical one is the possibility of studying the role of statistical fluctuations, relevant at low fluences. The paper recalls the main features of the physical model, describes the MC algorithm, and compares simulation results to experimental data (irradiations of LiNbO3 using silicon ions at 5 and 7.5 MeV and oxygen ions at 5 MeV). © 2006 American Institute of Physics.Peer Reviewe

Optical determination of three-dimensional nanotrack profiles generated by single swift-heavy ion impacts in lithium niobate

Three-dimensional (3D) profiles of single nanotracks generated by a low impact density of Cl ions at 46 MeV have been determined by optical methods, using an effective-medium approach. The buried location of the maximum stopping power induces a surface optical waveguiding layer even at ultralow fluences (1011-1013 at./cm2) that allows to obtain the effective refractive index profiles (from dark-mode measurements). Combining the optical information with Rutherford backscattering spectroscopy/channeling experiments, the existence of a surrounding defective halo around the amorphous track core has been ascertained. The 3D profile of the halo has also been determined. © 2006 American Institute of Physics.Peer Reviewe

Optical determination of three-dimensional nanotrack profiles generated by single swift-heavy ion impacts in lithium niobate

Three-dimensional (3D) profiles of single nanotracks generated by a low impact density of Cl ions at 46 MeV have been determined by optical methods, using an effective-medium approach. The buried location of the maximum stopping power induces a surface optical waveguiding layer even at ultralow fluences (1011-1013 at./cm2) that allows to obtain the effective refractive index profiles (from dark-mode measurements). Combining the optical information with Rutherford backscattering spectroscopy/channeling experiments, the existence of a surrounding defective halo around the amorphous track core has been ascertained. The 3D profile of the halo has also been determined. © 2006 American Institute of Physics.Peer Reviewe

Generation of high-confinement step-like optical waveguides in LiNbO3 by swift heavy ion-beam irradiation

3 pages, 4 figures, 1 table.We demonstrate a swift ion-beam irradiation procedure based on electronic (not nuclear) excitation to generate a large index jump step-like optical waveguide (Δn0 ≈ 0.2, Δne ≈ 0.1) in LiNbO3. The method uses medium-mass ions with a kinetic energy high enough to assure that their electronic stopping power Se(z) reaches a maximum value close to the amorphous (latent) track threshold inside the crystal. Fluorine ions of 20 and 22 MeV and fluences in the range (1–30)×1014 are used for this work. A buried amorphous layer having a low refractive index (2.10 at a wavelength of 633 nm) is then generated at a controlled depth in LiNbO3, whose thickness is also tuned by irradiation fluence. The layer left at the surface remains crystalline and constitutes the core of the optical waveguide which, moreover, is several microns far from the end of the ion range. The waveguides show, after annealing at 300 °C, low propagation losses ( ≈ 1 dB/cm) and a high second-harmonic generation coefficient (50%–80% of that for bulk unirradiated LiNbO3, depending on the fluence). The formation and structure of the amorphous layer has been monitored by additional Rutherford backscattering/channeling experiments.We acknowledge the funding of the project MAT2002– 03220 (MEC). A. García-Navarro acknowledges the financial support of the MEC through a FPU Fellowship and of the Madrid City Hall-Residencia de Estudiantes.Peer reviewe