1,770 research outputs found

    A simple DC-UPS based in forward-forward topology, design and simulation

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    This paper presents the analysis, design and simulation of a simple DC-UPS converter with integrated back-up and automatic transition. This converter makes automatic transitions between the main AC and the battery when a failure occurs; and it delivers uninterrupted DC power to the load through two independent power sources of commercial input power and battery power. The converter has the following characteristics: automatic transition between the main and the battery, no additional control to detect failure in main, single structure, galvanic isolation, multi output voltages capability and only one switch control for two operation modes: normal and back-up. The analysis, design and simulation for this converter are presented

    Isolated DC-DC UPS based in a forward-forward converter analysis and design

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    This paper presents the analysis, design and simulation from a simple DC-UPS converter with integrated back-up and automatic transition. This converter makes automatic transition between the main AC and the battery when a failure occurs, and it delivers uninterrupted DC power to the load through two independent power sources of commercial input power and battery power. The converter has the following characteristics: automatic transition between the main and the battery, no additional control to detect failure in the main, single structure, galvanic isolation, multi output voltages capability and only one switch control for two operation modes normal and back-up. The analysis, design, simulation and experimental results for this converter are presented

    Equilibration of Concentrated Hard Sphere Fluids

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    We report a systematic molecular dynamics study of the isochoric equilibration of hard-sphere fluids in their metastable regime close to the glass transition. The thermalization process starts with the system prepared in a non-equilibrium state with the desired final volume fraction {\phi} but with a prescribed non-equilibrium static structure factor S_0(k; {\phi}). The evolution of the {\alpha}- relaxation time {\tau}{\alpha} (k) and long-time self-diffusion coefficient DL as a function of the evolution time tw is then monitored for an array of volume fractions. For a given waiting time the plot of {\tau}{\alpha} (k; {\phi}, tw) as a function of {\phi} exhibits two regimes corresponding to samples that have fully equilibrated within this waiting time ({\phi} \leq {\phi}(c) (tw)), and to samples for which equilibration is not yet complete ({\phi} \geq {\phi}(c) (tw)). The crossover volume fraction {\phi}(c) (tw) increases with tw but seems to saturate to a value {\phi}(a) \equiv {\phi}(c) (tw \rightarrow \infty) \approx 0.582. We also find that the waiting time t^(eq)_w({\phi}) required to equilibrate a system grows faster than the corresponding equilibrium relaxation time, t^(eq)({\phi}) \approx 0.27 \times [{\tau}{\alpha} (k; {\phi})]^1.43, and that both characteristic times increase strongly as {\phi} approaches {\phi}^(a), thus suggesting that the measurement of equilibrium properties at and above {\phi}(a) is experimentally impossible

    ÁREA DE ACTIVIDAD Y COMPORTAMIENTO DEL LAGARTO Tropidurus hispidus (Spix 1825) (SAURIA-TROPIDURIDAE) EN CERRO COLORADO. CUMANÁ, ESTADO SUCRE, VENEZUELA

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    El área de actividad y algunas pautas en el comportamiento de adultos del lagarto Tropidurus hispidus fueron estudiados en Cerro Colorado, estado Sucre, Venezuela. Para calcular el área de actividad se utilizaron los métodos del polígono convexo y el de la elipse. El área de actividad en los machos (334,81 m2) resultó ser cualitativamente mayor que el de las hembras (105,85 m2), no se detectaron diferencias significativas entre ambas. En las hembras entre el área de actividad y la masa corporal, se registró una relación negativa y significativa, pero no así en los machos. Se identificaron ocho pautas de posición, cinco de mantenimiento y siete de desplazamiento.   PALABRAS CLAVE: Tropidurus hispidus, área de actividad, comportamiento, noreste, Venezuela.   ABSTRACT Home range and other patterns of behavior of adult lizards, Tropidurus hispidus, were studied in their habitat in Cerro Colorado, state of Sucre, Venezuela. The minimum convex polygon method and that of the ellipse were used to calculate the lizards’ area of activity. Mean home range for males resulted qualitatively larger (334.81 m2) than that of females (105.85 m2). No significant differences were found. Home range negatively correlated with body mass in females but not in males. Twenty behavioral patterns were identified, eight of position, five of maintenance, and seven of locomotion.   KEY WORDS: Tropidurus hispidus, home range, behavior, northeastern Venezuela

    Noncontact Optical Fiber Sensor for Measuring the Refractive Index of Liquids

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    A noncontact optical fiber sensor for measuring the refractive index of transparent liquids is proposed. It operates by calculating the path of a focused laser beam at 635 nm that travels across the boundaries of a liquid sample. The optical power Fresnel reflections are detected and, subsequently, the refractive index is determined as the ratio between the traveled beam paths when the liquid is deposited versus a reference without the liquid sample. Additionally, a mathematical analysis of the geometrical case is included. The theoretical data from our sensor are in good agreement with the experimental results. The resolution achieved by the sensor is better than 10−3 RIU

    Experiencias docentes potenciando los resultados de aprendizaje: 3ra. Jornada de innovación e investigación educativa de Unapec 2016

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    En la Universidad APEC (UNAPEC) se concibe la tercera jornada de innovación e investigación educativa como un espacio de reflexión pedagógica para el intercambio de saberes, experiencias y prácticas docentes orientadas a la mejora de los resultados de aprendizaje. Para esta ocasión, la misma tiene como objetivo proporcionar el diálogo profesional y el intercambio académico a fin de construir un entendimiento común sobre el proceso de mejora continua de la institución y promover la innovación e investigación como parte de la cultura de calidad, focalizada en el aprendizaje de los estudiantes

    Influence of elevated-CRP level-related polymorphisms in non-rheumatic Caucasians on the risk of subclinical atherosclerosis and cardiovascular disease in rheumatoid arthritis

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    Association between elevated C-reactive protein (CRP) serum levels and subclinical atherosclerosis and cardiovascular (CV) events was described in rheumatoid arthritis (RA). CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 exert an influence on elevated CRP serum levels in non-rheumatic Caucasians. Consequently, we evaluated the potential role of these genes in the development of CV events and subclinical atherosclerosis in RA patients. Three tag CRP polymorphisms and HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were genotyped in 2,313 Spanish patients by TaqMan. Subclinical atherosclerosis was determined in 1,298 of them by carotid ultrasonography (by assessment of carotid intima-media thickness-cIMT-and presence/absence of carotid plaques). CRP serum levels at diagnosis and at the time of carotid ultrasonography were measured in 1,662 and 1,193 patients, respectively, by immunoturbidimetry. Interestingly, a relationship between CRP and CRP serum levels at diagnosis and at the time of the carotid ultrasonography was disclosed. However, no statistically significant differences were found when CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were evaluated according to the presence/absence of CV events, carotid plaques and cIMT after adjustment. Our results do not confirm an association between these genes and CV disease in RA

    BVRI Light Curves for 29 Type Ia Supernovae

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    BVRI light curves are presented for 27 Type Ia supernovae discovered during the course of the Calan/Tololo Survey and for two other SNe Ia observed during the same period. Estimates of the maximum light magnitudes in the B, V, and I bands and the initial decline rate parameter m15(B) are also given.Comment: 17 pages, figures and tables are not included (contact first author if needed), to appear in the Astronomical Journa

    Thermal architecture for the QUBIC cryogenic receiver

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    QUBIC, the QU Bolometric Interferometer for Cosmology, is a novel forthcoming instrument to measure the B-mode polarization anisotropy of the Cosmic Microwave Background. The detection of the B-mode signal will be extremely challenging; QUBIC has been designed to address this with a novel approach, namely bolometric interferometry. The receiver cryostat is exceptionally large and cools complex optical and detector stages to 40 K, 4 K, 1 K and 350 mK using two pulse tube coolers, a novel 4He sorption cooler and a double-stage 3He/4He sorption cooler. We discuss the thermal and mechanical design of the cryostat, modelling and thermal analysis, and laboratory cryogenic testing.Fil: May, A. J.. University of Manchester; Reino UnidoFil: Chapron, C.. Astroparticule et Cosmologie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Coppi, G.. University of Manchester; Reino UnidoFil: D’Alessandro, G.. Università di Roma; ItaliaFil: de Bernardis, P.. Università di Roma; ItaliaFil: Masi, S.. Università di Roma; ItaliaFil: Melhuish, S.. University of Manchester; Reino UnidoFil: Piat, M.. Astroparticule et Cosmologie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Piccirillo, L.. University of Manchester; Reino UnidoFil: Schillaci, A.. Università di Roma; ItaliaFil: Thermeau, J. P.. Astroparticule et Cosmologie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Bonaparte, J.. Comisión Nacional de Energía Atómica; ArgentinaFil: Di Donato, Andrés Leonardo. Comisión Nacional de Energía Atómica; ArgentinaFil: Fasciszewski Zeballos, Alejandro Miguel. Comisión Nacional de Energía Atómica; ArgentinaFil: Gamboa Lerena, Martín Miguel. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Garcia, Beatriz Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Etchegoyen, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Gomez Berisso, Mariano. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: González, M.. Comisión Nacional de Energía Atómica; ArgentinaFil: Harari, Diego Dario. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kristukat, C.. Universidad Nacional de San Martín; ArgentinaFil: Medina, Maria Clementina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Ringegni, P.. Universidad Nacional de la Plata. Facultad de Ingeniería. Uidet Grupo de Ensayos Mecanicos Aplicados.; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Suarez, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Mundo, Luis Mariano. Universidad Nacional de la Plata. Facultad de Ingeniería. Uidet Grupo de Ensayos Mecanicos Aplicados.; ArgentinaFil: Watson, B.. University of Manchester; Reino UnidoFil: Wicek, F.. Laboratoire de l’Accélérateur Linéaire; FranciaFil: Zannoni, M.. Università degli Studi di Milano; ItaliaFil: Zullo, A.. Istituto Nazionale Di Fisica Nucleare; ItaliaMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IXEstados UnidosSociety of Photographic Instrumentation Engineer
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