2,838 research outputs found

    H.264/AVC inter prediction on accelerator-based multi-core systems

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    The AVC video coding standard adopts variable block sizes for inter frame coding to increase compression efficiency, among other new features. As a consequence of this, an AVC encoder has to employ a complex mode decision technique that requires high computational complexity. Several techniques aimed at accelerating the inter prediction process have been proposed in the literature in recent years. Recently, with the emergence of many-core processors or accelerators, a new way of supporting inter frame prediction has presented itself. In this paper, we present a step forward in the implementation of an AVC inter prediction algorithm in a graphics processing unit, using Compute Unified Device Architecture. The results show a negligible drop in rate distortion with a time reduction, on average, of over 98.8 % compared with full search and fast full search, and of over 80 % compared with UMHexagonS search

    Correlation between Spectroscopic and Mechanical Properties of Gold Nanocrystals under Pressure

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    The effects of nonhydrostatic pressure on the morphology and stability of gold nanorods (AuNRs) and nanospheres (AuNSs) in 4:1 methanol-ethanol mixtures were studied by optical absorption spectroscopy and transmission electron microscopy at pressures of up to 23 and 30 GPa, respectively. Solvent solidification and associated nonhydrostatic stresses were found to have a negligible effect on the shape and size of AuNSs. On the contrary, while AuNRs maintained their initial morphology in the hydrostatic range, the uniaxial stress component induced under nonhydrostatic conditions had a shearing effect on the AuNRs, breaking them into smaller particles. Interestingly, colloidal stability was maintained in all cases, and the particles showed no sign of aggregation, despite the severe nonhydrostatic conditions to which both AuNR and AuNS colloids were subjected.Financial support from Projects PGC2018-101464−B-I00 (Ministerio de Ciencia, Innovación y Universidades) and MALTA-Consolider Team (RED2018-102612-T) is acknowledged. We acknowledge J. A. Barreda-Argüeso and J. RuizFuertes for support with high-pressure measurements. P.M. thanks the ARC for grant CE170100026. L.M.L.-M. acknowledges grant PID2020-117779R and the Maria de Maeztu Units of Excellence Program (grant MDM-2017-0720) from the Spanish Ministerio de Ciencia e Innovación

    Zn-Al layered double hydroxides as efficient photocatalysts for NOx abatement

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    In this study,we report that layered double hydroxides (LDH) exhibited high photocatalytic activitiesin degrading NOx gases for the first time. ZnAl-CO3LDHs with a 1.5 to 3.0 Zn/Al ratio were prepared by a coprecipitation method both with and without hydrothermal treatment.Syntheses were carried out with high and low metal concentrations, the latter being the most favorablein obtaining pure LDHs in the whole Zn/Al ratio range. The samples were characterized by different techniques suchas PXRD, FT-IR, ICP mass, TGA, SBET, SEM and Diffuse reflectance (DR). The LDH particlesgrew as well-defined hexagonal nanolayers, whosesize and crystallization dependedon the synthetic procedure and the Zn/Al ratio. Those samples with lower crystallinity exhibit the highest specific surface area values (> 50 m2·g-1). The ZnAl-CO3LDHs were UV light responsive with band–gap valuescloseto 3.5 eV. The LDH photocatalysts show a high performance towards the photochemical oxidation process of NO gas, withefficiencies of around 55 %. Remarkably, the ZnAl-CO3photocatalysts exhibit an impressive selectivity towards the deNOx process, avoiding the emission of the toxic NO2gas into the atmosphere. Interestingly,these promising deNOx results are repeated when working for a long irradiation period or with the highest concentration of NO in polluted atmospheres

    Violadores y agresores sexuales

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    Los datos que se exponen en este boletín forman parte de dos trabajos de investigación más amplios, de los cuales uno ha sido presentado como tesis doctoral en la cátedra de Medicina Legal de la Universidad de Málaga. El objetivo de este último fue contrastar la personalidad, actitudes y experiencias sexuales de delincuentes sexuales violentos con los de un grupo control formado por delincuentes no sexuales. El segundo trabajo, aún en fase de realización, trata de establecer parámetros discriminadores entre los delincuentes sexuales en función de la edad de sus víctimas. Las conclusiones mostradas corresponden a un apartado común a ambos estudios, en el cual se describe, por una parte, el perfil del delincuente sexual violento (entendiendo por tal al autor de conductas tipificadas en el Código Penal como «violación» y «agresiones sexuales») y las circunstancias presentes en la ejecución de estos delitos y, por otra, se analizan algunas características de las víctimas

    Behavior of au nanoparticles under pressure observed by in situ small-angle X-ray scattering

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    The mechanical properties and stability of metal nanoparticle colloids under high-pressure conditions are investigated by means of optical extinction spectroscopy and small-angle X-ray scattering (SAXS), for colloidal dispersions of gold nanorods and gold nanospheres. SAXS allows us to follow in situ the structural evolution of the nanoparticles induced by pressure, regarding both nanoparticle size and shape (form factor) and their aggregation through the interparticle correlation function S(q) (structure factor). The observed behavior changes under hydrostatic and nonhydrostatic conditions are discussed in terms of liquid solidification processes yielding nanoparticle aggregation. We show that pressure-induced diffusion and aggregation of gold nanorods take place after solidification of the solvent. The effect of nanoparticle shape on the aggregation process is additionally discussed.We thank Professor Jan Dhont for helpful comments about nanoparticle diffusion in solid ethanol. F.R. acknowledges financial support from Projects PID2021-127656NB-I00 and MALTA-Consolider Team (RED2018-102612-T), and L.M.L.-M. from PID2020-117779RB-I00 and MDM-2017-0720, from the State Research Agency of Spain, Ministry of Science and Innovation. C.M.-S. acknowledges funding from the Spanish Ministry of Universities and the European Union-NextGeneration EU through the Margarita Salas research grant (C21.I4.P1). We acknowledge SOLEIL for the provision of synchrotron radiation facilities, and we would like to thank Dr. Javier Pérez, beamline supervisor, for assistance in using beamline SWING (proposals 20191731 and 20210678). This work benefited from the use of the SasView application, originally developed under NSF award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 research and innovation program under the SINE2020 project, grant agreement no. 654000

    Thermal characterization of Montmorillonite clays saturated with various cations

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    Emanation thermal analysis (ETA), thermogravimetry and high temperature XRD were used to characterize the thermal behavior during dehydration of natural Na montmorillonite (Upton Wyoming, USA) and homoionic montmorillonite (MMT) samples saturated with different cations, i.e. Li+, Cs+, NH 4 +, Mg2+ and Al3+. ETA results characterized radon mobility and microstructure changes that accompanied the mass loss of the samples due to dehydration on heating in air. A collapse of interlayer space between the silicate sheets after water release from the MMT samples was characterized by a decrease of the radon release rate, ΔE. Decreases in c-axis basal spacing (d 001) values determined from XRD patterns for the different montmorillonite samples follow the sequence: Mg−MMT>Al−MMT>Li−MMT>Na−MMT>NH4−MMT>Cs−MMT The decrease of the radon release rate (ΔE) determined by ETA that characterized microstructure changes due to collapse of interlayer space corresponded well to differences in the c-axis basal spacing (Δd 001) values determined from the XRD patterns before and after samples dehydration.Peer Reviewe

    Thermal characterization of Montmorillonite clays saturated with various cations

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    Emanation thermal analysis (ETA), thermogravimetry and high temperature XRD were used to characterize the thermal behavior during dehydration of natural Na montmorillonite (Upton Wyoming, USA) and homoionic montmorillonite (MMT) samples saturated with different cations, i.e. Li+, Cs+, NH 4 +, Mg2+ and Al3+. ETA results characterized radon mobility and microstructure changes that accompanied the mass loss of the samples due to dehydration on heating in air. A collapse of interlayer space between the silicate sheets after water release from the MMT samples was characterized by a decrease of the radon release rate, ΔE. Decreases in c-axis basal spacing (d 001) values determined from XRD patterns for the different montmorillonite samples follow the sequence: Mg−MMT>Al−MMT>Li−MMT>Na−MMT>NH4−MMT>Cs−MMT The decrease of the radon release rate (ΔE) determined by ETA that characterized microstructure changes due to collapse of interlayer space corresponded well to differences in the c-axis basal spacing (Δd 001) values determined from the XRD patterns before and after samples dehydration.Ministry of Education of Czech Republic LA–292España Ministerio de educación MAT2004-0264

    Photoluminescence Imaging and LBIC Characterization of Defects in mc-Si Solar Cells

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    Today's photovoltaic market is dominated by multicrystalline silicon (mc-Si) based solar cells with around 70% of worldwide production. In order to improve the quality of the Si material, a proper characterization of the electrical activity in mc-Si solar cells is essential. A full-wafer characterization technique such as photoluminescence imaging (PLi) provides a fast inspection of the wafer defects, though at the expense of the spatial resolution. On the other hand, a study of the defects at a microscopic scale can be achieved through the light-beam induced current technique. The combination of these macroscopic and microscopic resolution techniques allows a detailed study of the electrical activity of defects in mc-Si solar cells. In this work, upgraded metallurgical-grade Si solar cells are studied using these two techniques

    La Influencia del Consejo de Administración en la Adopción de un Código Ético: The Influence of the Board of Directors on Implementing an Ethics Code

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    Business ethics as a component of the corporate social responsibility, should be promoted from the Board of Directors. In this sense, the drawing up of a code of ethics would imply the formal statement of corporate principles which affect the responsibility with employees, shareholders, customers, the environment and every aspect of the society. Previous empirical evidence has emphasized the contradictory effect between the ownership of shares by directors and its effect on the shareholders’ economic interests, and a low concern with ethics issues by independent directors.In this line, this paper aims at establishing the effect of these two features of the Board of Directors on the incorporation of a ethical code for non-financial quoted Spanish companies. The finding show that the Board ownership leads to a entrenchment in the top management, by generating a divergence between owners’ and managers’ ethical interests. Faced with this situation, the presence of independent directors becomes necessary to reduce such conflicts.La ética empresarial, como uno de los componentes de la responsabilidad social corporativa, debe ser promovida desde el órgano superior de control de las organizaciones empresariales, el Consejo de Administración. En este sentido, la incorporación de un código ético supondría el establecimiento formal de los principios corporativos de la compañía que afectan a la responsabilidad con empleados, accionistas, consumidores, al entorno o a cualquier otro aspecto de la sociedad. La evidencia empírica previa pone de manifiesto efectos contradictorios entre la participación accionarial de los consejeros y su efecto sobre los intereses económicos de los accionistas, así como un reducido interés por parte de los consejeros independientes sobre temas éticos.En esta línea, el presente trabajo tiene como objetivo determinar el efecto de estas dos características del Consejo de Administración en la incorporación de un código ético por las empresas españolas no-financieras que cotizan en Bolsa. Los resultados obtenidos muestran que la participación accionarial provoca un atrincheramiento de la alta dirección, provocando una divergencia entre los intereses éticos de propietarios y directivos. En esta situación, la presencia de consejeros independientes se torna necesaria para reducir tales conflictos
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