778 research outputs found

    An Energetic Model for Detonation of Granulated Solid Propellants

    Get PDF
    Unexpected detonation of granular solid energetic materials is a key safety issue in the propellants manufacturing industry. In this work, a model developed for the characterization of the early stages of the detonation process of granular solid energetic materials is presented. The model relies on a two-phase approach which considers the conservation equations of mass, momentum, and energy and constitutive relations for mass generation, gas-solid particle interaction, interphase heat transfer, and particle-particle stress. The work considers an extension of approximated Riemann solvers and Total Variation Diminishing (TVD) schemes to the solid phase for the numerical integration of the problem. The results obtained with this model show a good agreement with data available in the literature and confirm the potential of the numerical schemes applied to this type of model. The results also permit to assess the effectiveness of different numerical schemes to predict the early stages of this transient combustion process.The research was performed thanks to the financial support of the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund throughout project RTC-2016-5194-8

    Can we measure mesopic pupil size with the cobalt blue light slit-lamp biomicroscopy method?

    Get PDF
    Producción CientíficaThe aim of this work is to assess a previously described slit-lamp biomicroscopy-based method (SLBM) for measuring pupil diameter and compare it to Colvard infrared pupillometry (CIP). METHODS: Two examiners performed three repeated measurements with each instrument in 40 healthy eyes. We determined the agreement of SLBM and CIP, intraobserver and interobserver repeatabilities, and interobserver concordance (kappa) and SLBM ability for detecting pupil sizes over 6.0 mm. RESULTS: The mean (±standard deviation [SD]) pupil diameter was 5.81 ± 0.70 mm with SLBM and 6.26 ± 0.68 mm with CIP (p = 0.01) averaging both examiner's results. Mean differences between the SLBM and CIP were -0.60 mm and -0.30 mm for each examiner using the average of the three readings (p = 0.02), and they were very similar using the first reading. Intraobserver reproducibility: the width of the 95% LoA ranged from 1.79 to 2.30 mm. The ICCs were 0.97 and 0.92 for SLBM, and 0.96 and 0.90 for CIP. Interobserver reproducibility: the width of the LoA ranged from 1.82 to 2.09 mm. Kappa statistics were 0.39 and 0.49 for the first and mean SLBM readings, respectively, and 0.45 for both the first and mean CIP readings. Sensitivity and specificity of SLBM for detection of pupils larger than 6 mm ranged from 55.56% to 73.68% and from 76.19% to 95.45%, respectively. The best trade-off between sensitivity and specificity ranged from 5.4 mm to 6.2 mm. CONCLUSIONS: Although the SLBM is quite repeatable, it underestimates mesopic pupil size and shows a too wide range of agreement with CIP. SLBM shows low sensitivity in detecting pupils larger than 6 mm, which may be misleading when planning anterior segment surgery. Previous grading-consensus training strategies may increase interrater reproducibility, and compensation for the systematic underestimation could improve accuracy of the SLBM

    Life Cycle Assessment of Cement Production with Marble Waste Sludges

    Get PDF
    The construction industry has a considerable environmental impact in societies, which must be controlled to achieve adequate sustainability levels. In particular, cement production contributes 5–8% of CO2 emissions worldwide, mainly from the utilization of clinker. This study applied Life Cycle Assessment (LCA) methodology to investigate the environmental impact of cement production and explore environmental improvements obtained by adding marble waste sludges in the manufacture of Portland cement. It was considered that 6–35% of the limestone required for its production could be supplied by marble waste sludge (mainly calcite), meeting the EN 197-1:2011 norm. Energy consumption and greenhouse gas (GHG) emission data were obtained from the Ecovent database using commercial LCA software. All life cycle impact assessment indicators were lower for the proposed “eco-cement” than for conventional cement, attributable to changes in the utilization of limestone and clinker. The most favorable results were achieved when marble waste sludge completely replaced limestone and was added to clinker at 35%. In comparison to conventional Portland cement production, this process reduced GHG emissions by 34%, the use of turbine waters by 60%, and the emission of particles into the atmosphere by 50%. Application of LCA methodology allowed evaluation of the environmental impact and improvements obtained with the production of a type of functional eco-cement. This approach is indispensable for evaluating the environmental benefits of using marble waste sludges in the production of cement.Junta de Andalucía and Fondo Europeo de Desarrollo Regional (FEDER) Ref. P18-RT-419

    A solution for tracking visitors in Smart Shopping environments: A real platform implementation based on Raspberry Pi

    Get PDF
    In parallel to the explosion of the use of wireless technologies to connect devices, the scientific community is continually aiming to take advantage of such technologies to provide new services. In this sense, there have been many attempts to exploit the information provided by IEEE802.11 and Bluetooth interfaces, commonly found in most of the smartphones that are being used at the time of writing. In this paper we describe a novel deployment that fosters such approach. Furthermore, the measurements that are gathered are made available, thanks to its integration within the SmartSantander testbed, and to the federation with complementary testbeds. The federation platform and the described deployment are outcomes of the FESTIVAL collaborative project (Europe-Japan). Besides depicting the corresponding software architecture, the paper also discusses some preliminary results that are used to assess the feasibility of the proposed scheme.This work was funded in part by the European Union’s Horizon 2020 Programme of the FESTIVAL project (Federated Interoperable Smart ICT Services Development and Testing Platforms) under grant agreement 643275, and from the Japanese National Institute of Information and Communications Technology. This work has been also supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE (TEC2015-71329-C2-1-R)

    Metallo-dielectric core-shell nanospheres as building blocks for optical three-dimensional isotropic negative-index metamaterials

    Get PDF
    Materials showing electromagnetic properties that are not attainable in naturally occurring media, so-called metamaterials, have been lately, and still are, among the most active topics in optical and materials physics and engineering. Among these properties, one of the most attractive ones is the subdiffraction resolving capability predicted for media having an index of refraction of -1. Here, we propose a fully three-dimensional, isotropic metamaterial with strong electric and magnetic responses in the optical regime, based on spherical metallo-dielectric core-shell nanospheres. The magnetic response stems from the lowest, magnetic-dipole resonance of the dielectric shell with a high refractive index, and can be tuned to coincide with the plasmon resonance of the metal core, responsible for the electric response. Since the response does not originate from coupling between structures, no particular periodic arrangement needs to be imposed. Moreover, due to the geometry of the constituents, the metamaterial is intrinsically isotropic and polarization independent. It could be realized with current fabrication techniques with materials such as silver (core) and silicon or germanium (shell). For these particular realistic designs, the metamaterials present a negative index in the range of 1.2-1.55 μm.Ministerio de Ciencia e Innovación CSD2008-00066, FIS2009- 11264Comunidad de Madrid MICROSERES P2009/TIC-147

    Vehículo autónomo polivalente para trabajos en invernadero.

    Get PDF
    Número de publicación: ES2329107 A1 (20.11.2009) También publicado como: ES2329107 B2 (07.09.2010) Número de Solicitud: Consulta de Expedientes OEPM (C.E.O.) P200801645 (19.05.2008)Vehículo autónomo polivalente para trabajos en invernadero. El objeto de la invención es un vehículo que de forma autónoma puede moverse entre las líneas de cultivo en invernadero para realizar diferentes operaciones. Está dotado de un chasis diseñado para poder recibir diferentes implementos, así como un punto de enganche en la parte trasera para el acoplamiento de máquinas y equipos. Dispone de un sistema de transmisión hidrostático controlado electrónicamente que permite mover el equipo en un rango de velocidades continuo para adaptarla convenientemente a las exigencias del trabajo, además de suministrar energía a los implementos que la requieran. El movimiento del vehículo se consigue mediante el equilibrio dinámico de cada una de las orugas que componen el sistema de rodadura. Para ello dispone de un sistema sensorial compuesto por captadores de presión, codificadores incrementales y un radar. El sistema sensorial del vehículo se completa con sensores de ultrasonido distribuidos por todo el perímetro (detección de obstáculos), una brújula magnética (orientación del vehículo) y sensores de seguridad (prevenir colisiones). La información suministrada por el sistema sensorial permite la localización y navegación del vehículo en el entorno de trabajo. Toda la información es gestionada por un sistema empotrado, donde se ejecutan los programas que controlan el vehículo. El equipo también está dotado de una cámara multiespectral, adaptada para realizar un seguimiento continuo de determinados parámetros del cultivo, como pueden ser: detectar problemas fitosanitarios y de nutrición, controlar la evolución de la masa vegetal, localizar frutos, determinar la maduración de los frutos, etc.Universidad de Almerí

    Intervención fisioterápica en atención primaria de una fractura distal de radio tras reducción cerrada: A propósito de un caso clínico

    Get PDF
    Introducción: A día de hoy se sigue cuestionando la efectividad de la fisioterapia en el manejo de las fracturas distales de radio, mientras que los criterios para pautar rehabilitación fisioterápica una vez retirada la inmovilización todavía no quedan claros, a pesar de ser una de las fracturas más comunes en el cuerpo humano y que acarrean más lesiones asociadas de partes blandas y complicaciones.Objetivos: Describir, analizar y valorar a través de un caso clínico el efecto de la aplicación de un plan de tratamiento fisioterápico en una fractura distal de radio que se somete a tratamiento conservador.Metodología: Se trata de un caso clínico de modelo básico, donde la muestra es un individuo (n=1) en el que se realiza una evaluación inicial pre-tratamiento fisioterápico, atendiendo a la funcionalidad y calidad de vida, dolor, rango de movimiento y fuerza. Se realizaron 9 sesiones de tratamiento fisioterápico repartidas en 6 semanas consecutivas y posteriormente una evaluación final post-tratamiento fisioterápico.Resultados: En la evaluación final post-tratamiento fisioterápico se observaron mejorías en todos los aspectos evaluados al comienzo del tratamiento, siendo especialmente relevantes los conseguidos para el rango de movimiento. Discusión: El plan de intervención fisioterápica diseñado mostró efectividad clínica para esta patología, no obstante, los resultados no pueden extrapolarse a otros pacientes con la misma patología al tratarse de un caso clínico (n=1), sin embargo, sí que puede servir para generar nuevas hipótesis, y por tanto, anteceder a estudios experimentales. Conclusiones: Las modalidades y técnicas fisioterápicas seleccionadas para este caso mostraron eficacia para las 4 variables principales del estudio.<br /

    Characteristics and Behavior of Di erent Catalysts Used for Water Decontamination in Photooxidation and Ozonation Processes

    Get PDF
    The objective of this study was to summarize the results obtained in a wide research project carried out for more than 15 years on the catalytic activity of di erent catalysts (activated carbon, metal–carbon xerogels/aerogels, iron-doped silica xerogels, ruthenium metal complexes, reduced graphene oxide-metal oxide composites, and zeolites) in the photooxidation (by using UV or solar radiation) and ozonation of water pollutants, including herbicides, naphthalenesulfonic acids, sodium para-chlorobenzoate, nitroimidazoles, tetracyclines, parabens, sulfamethazine, sodium diatrizoate, cytarabine, and surfactants. All catalysts were synthesized and then texturally, chemically, and electronically characterized using numerous experimental techniques, including N2 and CO2 adsorption, mercury porosimetry, thermogravimetric analysis, X-ray di raction, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, di use reflectance UV–vis spectroscopy, photoluminescence analysis, and transmission electron microscopy. The behavior of these materials as photocatalysts and ozonation catalysts was related to their characteristics, and the catalytic mechanisms in these advanced oxidation processes were explored. Investigations were conducted into the e ects on pollutant degradation, total organic carbon reduction, and water toxicity of operational variables and the presence of di erent chemical species in ultrapure, surface, ground, and wastewaters. Finally, a review is provided of the most recent and relevant published studies on photocatalysis and catalyzed ozonation in water treatments using similar catalysts to those examined in our project.Spanish Ministry of Economy, Industry and Competitiveness CTQ2016-80978-C2-1-REuropean Union (EU) CTQ2016-80978-C2-1-RJunta de Andalucía P18-RT-419
    corecore