Numerical modelling of the cyclic structural behavior of slender steel members with restrained buckling

Este trabajo presenta un modelo numérico del comportamiento estructural cíclico de barras de pandeo restringido, comúnmente utilizadas como una alternativa a las clásicas barras de arriostramiento concéntrico para protección sismorresistente de pórticos de edificios y otras estructuras. Estos dispositivos se componen normalmente de un núcleo de acero esbelto recubierto por una carcasa de mayor rigidez que tiene por objeto impedir su pandeo cuando se encuentra comprimido. La carcasa puede ser de mortero o de acero, y una interfaz de deslizamiento está interpuesta entre el núcleo y la carcasa para evitar la transferencia excesiva de tensiones tangenciales. El comportamiento del núcleo de acero se describe mediante un modelo de daño y plasticidad, el comportamiento de la carcasa de mortero se describe mediante un modelo de daño isótropo y el comportamiento de la interfaz de deslizamiento se describe mediante un modelo de penalización de contacto. Estos 3 modelos se implementan en el paquete de software Abaqus siguiendo una formulación explícita. En un artículo previo publicado en una revista de ingeniería sísmica se describió someramente el modelo, se comprobó de forma preliminar su capacidad para reproducir el comportamiento cíclico de barras de pandeo restringido y se compararon satisfactoriamente sus resultados con los de ensayos experimentales; el objetivo de este trabajo es describir el modelo en profundidad y discutir en mayor extensión las valoraciones acerca de su utilidad.This work presents a numerical model of the cyclic structural behavior of dissipative buckling-restrained braces, commonly used as an alternative to classical concentric braces for seismic protection of building frames and other structures. Such devices are usually composed of a slender steel core embedded in a stockiest casing that is intended to prevent its buckling when it is under compression. The casing is made either of mortar or steel, and a sliding interface is interposed between the core and the casing to prevent excessive shear stress transfer. The behavior of the steel core is described by a damage and plasticity model; the behavior of the mortar casing is described by an isotropic damage model and the sliding behavior of the interface is described by a contact penalty model. These 3 models are implemented in the Abaqus software package following an explicit formulation. In a previous article (published in an earthquake engineering journal) the model was briefly described, its ability to reproduce the cyclical behavior of buckling-restrained braces was preliminarily pointed out and their results were satisfactorily compared with those of experimental tests. The aim of this paper is to describe the model thoroughly and to present new judgments about its usefulness.Peer Reviewe

An abridged Spanish version of Sexual Double Standard Scale: Factorial structure, reliability and validity evidence

Background/Objective Sexual double standard (SDS) has long been associated to several dimensions of sexual health. Therefore the assessment of SDS is relevant and requires self-reported measures with adequate psychometric properties. This study aims to adapt the Sexual Double Standard Scale (SDSS) into heterosexual Spanish population and examine its psychometric properties. Method: Using quota incidental sampling, we recruited a sample of 1, 206 individuals (50% women), distributed across three groups based on their age (18-34, 35-49 and 50 years old and older). Results: We performed both, Exploratory Factor Analysis and Confirmatory Factor Analysis. An abridged version was yielded, consisting of 16 items distributed into two factors (Acceptance for sexual freedom and Acceptance for sexual shyness). A second-order factor structure was also adequate, which facilitates the use of a global index for SDS. Reliability, based on internal consistency and temporal stability was good for the factors. Evidence of validity is also shown and reported. Conclusions: This adapted version of the SDSS is reliable and valid. The importance for its use to estimate the prevalence of both traditional and modern forms of this phenomenon is discussed. Antecedentes/Objetivo: El doble estándar sexual (DES) se ha asociado a distintas dimensiones de la salud sexual, por lo que su evaluación es relevante y requiere de instrumentos con ade- cuadas propiedades psicométricas. Se plantea la adaptación a población heterosexual espa ~ nola de la Sexual Double Standard Scale (SDSS) y examinar sus propiedades psicométricas. Método : Mediante un muestreo incidental por cuotas se obtuvo una muestra de 1.206 sujetos (50% mujeres), distribuidos en tres grupos en función de la edad (18-34 a ~ nos, 35-49 a ~ nos y 50 a ~ nos o más). Resultados : Mediante Análisis Factorial Exploratorio y Análisis Factorial Confirmatorio se consiguió una versión de 16 ítems distribuidos en dos factores (Aceptación de la libertad sexual y Aceptación del recato sexual), cuya combinación en un factor de segundo orden per- mite obtener un índice global de doble estándar sexual. La fiabilidad de consistencia interna y test-retest es óptima para los dos subfactores y sus medidas presentan adecuados índices de validez. Conclusiones : Esta versión adaptada de la SDSS es fiable y válida. Se discute su impor- tancia para detectar la prevalencia de DES tradicional y de expresiones más modernas de este fenómeno

A new composition-sensitive parameter for Ultra-High Energy Cosmic Rays

A new family of parameters intended for composition studies in cosmic ray surface array detectors is proposed. The application of this technique to different array layout designs has been analyzed. The parameters make exclusive use of surface data combining the information from the total signal at each triggered detector and the array geometry. They are sensitive to the combined effects of the different muon and electromagnetic components on the lateral distribution function of proton and iron initiated showers at any given primary energy. Analytical and numerical studies have been performed in order to assess the reliability, stability and optimization of these parameters. Experimental uncertainties, the underestimation of the muon component in the shower simulation codes, intrinsic fluctuations and reconstruction errors are considered and discussed in a quantitative way. The potential discrimination power of these parameters, under realistic experimental conditions, is compared on a simplified, albeit quantitative way, with that expected from other surface and fluorescence estimators.Comment: 27 pages, 17 figures. Submitted to a refereed journa

The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs

Indexación: Scopus.J.M. acknowledges support from CONICYT-Chile through CONICYT-PCHA/Doctorado-Nacional/2014-21140892. J.M., F.F., G.C.V., and G.M. acknowledge support from the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS). F.F. acknowledges support from Conicyt through the Fondecyt Initiation into Research project No. 11130228. J.M., F.F., J.S.M., G.C.V., and S.G. acknowledge support from Basal Project PFB-03, Centro de Modelamiento Matemáico (CMM), Universidad de Chile. P.L. acknowledges support by Fondecyt through project #1161184. G.C.V. gratefully acknowledges financial support from CON-ICYT-Chile through FONDECYT postdoctoral grant number 3160747 and CONICYT-Chile and NSF through the Programme of International Cooperation project DPI201400090. P.H. acknowledges support from FONDECYT through grant 1170305. L.G. was supported in part by the US National Science Foundation under grant AST-1311862. G.M. acknowledges support from Conicyt through CONICYT-PCHA/Magís-terNacional/2016-22162353. Support for T.d.J. has been provided by US NSF grant AST-1211916, the TABASGO Foundation, and Gary and Cynthia Bengier. R.R.M. acknowledges partial support from BASAL Project PFB-06, as well as FONDECYT project N◦1170364. Powered@NLHPC: this research was supported by the High Performance Computing infrastructure of the National Laboratory for High Performance Computing (NLHPC), PIA ECM-02, CONICYT. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, the University of California Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologi-cas-Madrid, the University of Chicago, University College London, the DES-Brazil consortium, the University of Edinburgh, ETH-Zurich, the University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Lab, Stanford University, the University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financia-dora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the universe,” and the DES collaborating institutions. Facility: CTIO:1.5 m (DECam).The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-3881/aadfd

Diseño de un sistema automático de selección de frutos de café mediante técnicas de visión artificial

En el presente artículo se propone un sistema de visión artificial para la detección del fruto de café apto para producción. Para lograr esta detección se desarrollaron dos algoritmos, uno encargado de clasificar los frutos de café en maduros o no maduros, y otro que detecta la presencia de la plaga de la broca. Para el primero se extrajeron características de color y se usó un clasificador bayesiano. Por otra parte, el algoritmo de detección de brocas busca zonas negras en la imagen, esto debido a que la evidencia dejada por esta plaga son orificios en la superficie del fruto. Además, se diseñó un sistema mecánico para el transporte de los frutos de café durante el proceso, y un mecanismo de extracción para separar los frutos, una vez estos sean clasificados por el algoritmo. Los resultados obtenidos mostraron una efectividad del 87%.In this Article, it is proposed a computer vision system, which can detect whether a coffee fruit is suitable for production or not. In order to achieve this detection, two algorithms were developed, one to classify the coffee fruit in the ripe orunripe state, and the other to detect the presence of the ‘coffee berry borer’. The first one uses a Bayesian Classifier toidentify the color of the fruit, and the second algorithm searches for the holes made by the coffee berry borer on thesurface of the product. Moreover, a mechanical system was designed for the transportation and separation of the coffeefruits. In the first stage, coffees are transported as pictures of them are taken. At the end of this stage, the separationmechanism alters the path of the fruit based on the result of the classifier. The system proposed obtained aneffectiveness of 87%. &nbsp

Diseño de un sistema automático de selección de frutos de café mediante técnicas de visión artificial

En el presente artículo se propone un sistema de visión artificial para la detección del fruto de café apto para producción. Para lograr esta detección se desarrollaron dos algoritmos, uno encargado de clasificar los frutos de café en maduros o no maduros, y otro que detecta la presencia de la plaga de la broca. Para el primero se extrajeron características de color y se usó un clasificador bayesiano. Por otra parte, el algoritmo de detección de brocas busca zonas negras en la imagen, esto debido a que la evidencia dejada por esta plaga son orificios en la superficie del fruto. Además, se diseñó un sistema mecánico para el transporte de los frutos de café durante el proceso, y un mecanismo de extracción para separar los frutos, una vez estos sean clasificados por el algoritmo. Los resultados obtenidos mostraron una efectividad del 87%.In this Article, it is proposed a computer vision system, which can detect whether a coffee fruit is suitable for production or not. In order to achieve this detection, two algorithms were developed, one to classify the coffee fruit in the ripe orunripe state, and the other to detect the presence of the ‘coffee berry borer’. The first one uses a Bayesian Classifier toidentify the color of the fruit, and the second algorithm searches for the holes made by the coffee berry borer on thesurface of the product. Moreover, a mechanical system was designed for the transportation and separation of the coffeefruits. In the first stage, coffees are transported as pictures of them are taken. At the end of this stage, the separationmechanism alters the path of the fruit based on the result of the classifier. The system proposed obtained aneffectiveness of 87%. &nbsp

Effectiveness of integrated treatment for eating disorders in Spain: protocol for a multicentre, naturalistic, observational study

Introduction Eating disorders (EDs) are complex pathologies which require equally complex treatment strategies. These strategies should be multidisciplinary, personalised interventions, performed in appropriate settings along a healthcare continuum from inpatient to community care. Personalisation, and the complexity of levels of care and interventions make evaluation of treatments difficult. The present study aims to measure the effectiveness of a complex treatment programme for EDs which includes hospitalisation, day hospital and outpatient settings. Our purpose is to assess the complete therapeutic process of each patient through all these levels of care, capturing the multiplicity of trajectories that a programme of these characteristics involves. Methods and analysis This protocol describes a multicentre, naturalistic, observational study. All patients starting between November 2017 and October 2020 in a healthcare network for EDs in Spain are being invited to participate. The first phase of intensive change monitoring to November 2020 is followed by lower intensity follow-up until October 2025. In the first phase progress of all participants is assessed every 3 weeks using specific measures for ED and the Clinical Outcomes Routine Evaluation system, a family of instruments specifically designed to measure change in psychotherapy. In the second phase data collection will happen quarterly. Both cross-sectional and longitudinal analyses will be conducted, with a special focus on patterns and predictors of change studied through multilevel linear models. Ethics and dissemination The study has been approved by the Research Bioethics Committee of the University of Barcelona (no. IRB00003099) and the ethical committee of ITA Mental Health, the organisation to which all participating centres belong. Dissemination will be in papers for peer-reviewed research journals and to clinicians working with ED. Trial registration number NCT04127214

Fatty Acid Methyl Esters as Biosolvents of Epoxy Resins: A Physicochemical Study

The C8 to C18 fatty acid methyl esters (FAME) have been compared as solvents for two epoxy resin pre-polymers, bisphenol A diglycidyl ether (DGEBA) and triglycidyl paminophenol ether (TGPA). It was found that the solubilization limits vary according to the ester and that methyl caprylate is the best solvent of both resins. To explain these solubility performances, physical and chemical properties of FAME were studied, such as the Hansen parameters, viscosity, binary diffusion coefficient and vaporization enthalpy. Determination of the physicochemical parameters of FAME was carried out by laboratory experimentations and by calculation from bibliographic data. The Hansen parameters of FAME and epoxy resins pre-polymers were theoretically and experimentally determined. The FAME chain length showed a long dependence on the binary diffusion parameters and kinematic viscosity, which are mass and momentum transport properties. Moreover, the vaporization enthalpy of these compounds was directly correlated with the solubilization limits

Casting Fe-Al-based intermetallics microalloyed with Li and Ag

The effect on the mechanical properties at room temperature of Li and Ag additions to the Fe–Al (40 at.%)-based alloy produced by conventional casting were evaluated in this work. Alloying elements were added into a previously molted Fe–(40 at.%) aluminum-based alloy, stirred, and then cast into sand molds to directly produce tensile specimens. To determine the mechanical properties, tensile tests and hardness measurements were performed. The additions of both Ag and Li showed an increase in ductility and tensile strength of the intermetallic alloys. In addition, hardness was substantially increased with the Li addition. Lithium additions promoted a solid solution hardening, whereas 3 at.% of Ag additions promoted ductility due to a microstructural modification and to the formation of a soft Ag 3 Al phase. Characterization by both optical and electronic microscopy, energy dispersive spectroscopy microanalysis, and x-ray diffraction supported the mechanical characterization.Peer ReviewedPostprint (author's final draft