328 research outputs found

    High frequency pCO2 monitoring in the Mediterranean coastal waters

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    Monitoring the Air-Sea pCO2 variability in the coastal areas is a priority due to the effect of the biological and biogeochemistry process on this process. The Northwestern Mediterranean Sea is an oligotrophic area in a semi-closed basin, therefore the changes on the surface waters properties take place faster than in other seas. This work focuses in the establishment of a pCO2 monitor system and other related sensors at the OBSEA surface buoy.Peer Reviewe

    Performance of NiCrAlY Coatings Deposited by Oxyfuel Thermal Spraying in High Temperature Chlorine Environment

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    A microcrystalline Ni-22Cr-10Al-1Y (wt.%) coating was deposited on AISI 304 stainless steel by the oxyfuel thermal spray technique. The deposited coating was subjected to heat treatment to improve the microstructure characteristics and its corresponding high-temperature properties. The isothermal high-temperature corrosion behavior at 650 and 700 °C in synthetic air and in the presence of 1% Cl2 was investigated using thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results indicated that the deposited NiCrAlY coating possessed acceptable oxidation-corrosion resistance at 650 °C owing to the formation of extensive amounts of the protective oxide of Cr2O3; NiO and a lesser amount of a Cr1.12 Ni2,88 metallic phase are also formed. At 700 °C, the coating lost its protective characteristic because of the excessive consumption of thermodynamically stable phases by oxidation-chlorination process. In this case, the steel base and the coating were attacked by chlorine during the exposure time; the mass gain of the NiCrAlY coating was slightly higher and provided only a limited protection up to 11 h; thereafter, breakdown of the layer of oxides occurred and this is attributed to the formation of non-protective oxides mainly β-Fe2O3 and Fe21.33O32 and the depletion of chromium

    Numerical analysis of the manufacturing processes of a mock-up of the ITER NHF First Wall Panel

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    The objective of ITER is to build a new Tokamak, with the goal of demonstrating the scientific and technical feasibility of fusion power. The First Wall Panels are the inner component of the reactor, built with different materials that must support high heat flux levels inside the vacuum vessel. The manufacturing processes of the First Wall are a complex procedure including bending, hipping and cutting procedures which, in general, lead to residual stresses and distortions of the fabricated component. In this work, the analysis of the thermo-mechanical response of a simplified prototype of the ITER NHF First Wall Panel is presented from the numerical point of view. The experimental procedure within each phase of the whole manufacturing process is described. Residual stresses and distortions have been measured and analyzed. The numerical simulation of the manufacturing process includes the description of the main hypothesis, the applied loads and the boundary conditions assumed at every stage of the process. Special attention is paid to the simulation of machining and cutting by means of an ad-hoc element deactivation strategy. The numerical results are compared with the experimental evidence to show the prediction capability and the limitations of the proposed numerical model

    Hydrogen-free SiCN films obtained by electron cyclotron resonance plasma: a study of composition, optical and luminescent properties

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    The Electrochemical Society, Inc. 2007. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in Journal of the Electrochemical Society Vol. 154 Issue 4 (2007): H325-H33

    Necrosis aséptica de astrágalo: presentación de un caso en la infancia

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    Se presenta un caso de necrosis aséptica de astrágalo en la infancia de origen idiopático que, hasta donde sabemos, resulta único en la literatura mundial. Se trata de una niña con un síndrome de Klippel-Trenaunay que debuta a la edad de 8 años con un cuadro de dolor e inflamación intermitente en tobillo derecho. Se realiza estudio mediante radiografías simples, RNM y gammagrafía con "Tc, llegando al diagnóstico de necrosis avascular de astrágalo. Se trata mediante descarga del miembro durante 3 meses, realizando la paciente vida normal con mínimas molestias a los 3 años del diagnósticoWe present one case of idiopathic avascular necrosis of the talus in a child.To our knowledge, this is the first case reported in the literature. The patient is a girl diagnosed of Klippel-Trenaunay syndrome of the ipsilateral limb. When she was 8 years old began with pain and swelling in the right ankle. Simple X-ray, isotopic bone scan and MRI were done, and she was diagnosed of avascular necrosis of the talar dome. The treatment was no weight bearing for three months. She has no sympthoms three years after diagnosis

    Oxidación a 1123 K de sistemas multicapa AISI 304-Ni/Al-Al2O3/TiO2 depositados mediante proyección por llama

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    The oxidation behaviour of alumina/titania (97/3, 87/13 and 60/40) ceramic coatings using a Ni-Al coupling layer was studied in a thermobalance. Both layers were deposited on an AISI 304 stainless steel base metal by the flame spray technique. The coated steel was heated from room temperature to 1,123 K at 40 K min–1, oxidized in air for 50 h, and then cooled to room temperature at 40 K min–1. The mass gain was mainly attributed to the oxidation of Ni-Al coupling layer. Kinetic laws, DW·S–1 (mg.mm–2) vs. time (hours) were close to a parabolic plot for each sample. Surface composition of ceramic top layer and the cross section of multilayer system were analysed using a wide range of experimental techniques including Scanning Electron Microscopy (SEM), equipped with a link energy dispersive X-Ray spectroscopy (EDX) and X-Ray diffraction (XRD) before and after the oxidation process. Coatings 97/3 and 87/13 presented a stable structure after flame spray deposition and they did not evolve with the oxidation process, while most of the 60/40 coating changed to a metastable structure after deposition and to a more stable structure after oxidation with high micro-cracks content. SEM and EDX microanalysis of the cross-sections showed that significant oxidation and a weak intergranular precipitation had been produced in the coupling layer and on the stainless steel base metal, respectively.El comportamiento a oxidación de recubrimientos cerámicos alúmina/titania (97/3, 87/13, 60/40) usando una capa de anclaje Ni-Al se ha estudiado mediante una termobalanza. Ambas capas se han depositado sobre un acero inoxidable AISI 304 utilizando la técnica de proyección llama (FS). El acero recubierto se ha calentado desde la temperatura ambiente hasta 1.123 K a 40 K min–1, se ha oxidado al aire durante 50 h, y luego se ha enfriado hasta la temperatura ambiente a 40 K min–1. La ganancia en masa se atribuye a la oxidación de la capa de enganche Ni-Al. La cinética DW·S–1 (mg.mm–2) vs. tiempo (horas) se ha ajustado a una ley parabólica para todas las muestras. La composición super- ficial de la capa cerámica y la sección transversal del sistema multicapa se han analizado mediante las técnicas de Microscopía Electrónica de Barrido (SEM), Espectroscopia de Energías Dispersivas de Rayos X (EDX), Difracción de Rayos X (XRD) antes y después del proceso de oxidación. Los recubrimientos 97/3 y 87/13 han presentado una estruc- tura estable tras el proceso de deposición por proyección por llama y esta estructura tampoco ha evolucionado después de la oxidación, mientras la mayor parte del recubrimiento 60/40 ha cambiado a una estructura metaestable después la deposición y finalmente ha evolucionado a una estructura más estable después de la oxidación con alto contenido de microagrietamiento. El microanálisis mediante SEM y EDX de las secciones transversales han mostrado una oxidación significativa en la capa de enganche y una débil precipitación intergranular en el material base AISI 30

    On the measurement of leptonic CP violation

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    We show that the simultaneous determination of the leptonic CP-odd phase δ\delta and the angle θ13\theta_{13} from the subleading transitions νeνμ\nu_e\to\nu_\mu and νˉeνˉμ{\bar\nu}_e\to{\bar\nu}_\mu results generically, at fixed neutrino energy and baseline, in two degenerate solutions. In light of this, we refine a previous analysis of the sensitivity to leptonic CP violation at a neutrino factory, in the LMA-MSW scenario, by exploring the full range of δ\delta and θ13\theta_{13}. Furthermore, we take into account the expected uncertainties on the solar and atmospheric oscillation parameters and in the average Earth matter density along the neutrino path. An intermediate baseline of O(3000) km is still the best option to tackle CP violation, although a combination of two baselines turns out to be very important in resolving degeneracies.Comment: 19 pages, 14 figures, uses epsfi

    Mechanical and tribological properties of alumina/titania coatings deposited by Ooxifuel

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    En este trabajo se ha estudiado, las fases, las propiedades mecánicas y la resistencia al desgaste abrasivo de recubrimientos cerámicos alumina/titania proyectados por el proceso de oxifuel (spray llama). La proporción de titania tiene una fuerte influencia sobre la porosidad de los recubrimientos, habiéndose observado una disminución casi-lineal de la porosidad con el incremento de titania. Las fases cristalinas que resultan después de la proyección han variado según la naturaleza del polvo y el proceso térmico experimentado. Mientras la dureza obtenida depende sólo del porcentaje en peso de titania, la tenacidad es una función inversa de la dureza, y, la resistencia al desgaste por abrasión es una función creciente con la dureza de los recubrimientosIn this paper the porosity, phases, mechanical properties and abrasive wear resistance of ceramic layers of Al2O3/TiO2 deposited using the flame spray process are evaluated. The proportion of titania has a strong influence on the porosity of the coating, having observed an approximately linear plot decrease with the increasing of titania´s content. Crystalline phases of the deposited layers changed according to the characteristics of the powder and the thermal process employed. It has been observed that hardness depends only on the titania percentage, also toughness decreases with coatings hardness but resistance to abrasive wear traces an increasing lineal plot with this propert

    Biphasic concentration patterns in ionic transport under nanoconfinement revealed in steady-state and time-dependent properties

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    Ion permeation across nanoscopic structures differs considerably from microfluidics because of strong steric constraints, transformed solvent properties, and charge-regulation effects revealed mostly in diluted solutions. However, little is known about nanofluidics in moderately concentrated solutions, which are critically important for industrial applications and living systems. Here, we show that nanoconfinement triggers general biphasic concentration patterns in a myriad of ion transport properties by using two contrasting systems: a biological ion channel and a much larger synthetic nanopore. Our findings show a low-concentration regime ruled by classical Debye screening and another one where ion–ion correlations and enhanced ion–surface interactions contribute differently to each electrophysiological property. Thus, different quantities (e.g., conductance vs noise) measured under the same conditions may appear contradictory because they belong to different concentration regimes. In addition, non-linear effects that are barely visible in bulk conductivity only in extremely concentrated solutions become apparent in nanochannels around physiological conditions

    Fostering carbon credits to finance wildfire risk reduction forest management in Mediterranean landscapes

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    Despite the need for preserving the carbon pools in fire-prone southern European landscapes, emission reductions from wildfire risk mitigation are still poorly understood. In this study, we estimated expected carbon emissions and carbon credits from fuel management projects ongoing in Catalonia (Spain). The planning areas encompass about 1000 km(2) and represent diverse fire regimes and Mediterranean forest ecosystems. We first modeled the burn probability assuming extreme weather conditions and historical fire ignition patterns. Stand-level wildfire exposure was then coupled with fuel consumption estimates to assess expected carbon emissions. Finally, we estimated treatment cost-efficiency and carbon credits for each fuel management plan. Landscape-scale average emissions ranged between 0.003 and 0.070 T CO2 year(-1) ha(-1). Fuel treatments in high emission hotspots attained reductions beyond 0.06 T CO2 year(-1) per treated ha. Thus, implementing carbon credits could potentially finance up to 14% of the treatment implementation costs in high emission areas. We discuss how stand conditions, fire regimes, and treatment costs determine the treatment cost-efficiency and long-term carbon-sink capacity. Our work may serve as a preliminary step for developing a carbon-credit market and subsidizing wildfire risk management programs in low-revenue Mediterranean forest systems prone to extreme wildfires.This study was funded by the LIFE CLIMARK Project (LIFE16 CCM/ES/000065), and the Ministerio de Economia y Competitividad. Juan de la Cierva Formacion research fellows FJCI-2016-31090 and FIJCI-2016-30049)
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