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Nomenclatura Unesco > (22) Física

Mostrando recursos 45,601 - 45,620 de 70,120

45601. Analytical approach to sorting in periodic and random potentials - Gleeson, James P.; Sancho, Jose Maria; Lacasta Palacio, Ana María; Lindenberg, K.
There has been a recent revolution in the ability to manipulate micrometer-sized objects on surfaces patterned by traps or obstacles of controllable configurations and shapes. One application of this technology is to separate particles driven across such a surface by an external force according to some particle characteristic such as size or index of refraction. The surface features cause the trajectories of particles driven across the surface to deviate from the direction of the force by an amount that depends on the particular characteristic, thus leading to sorting. While models of this behavior have provided a good understanding of these observations, the...

45602. El fuego en la web - Romero Castro, Aldo Humberto; Lopez Moreno, Sinhue; Lacasta Palacio, Ana María

45603. Propagación del fuego en parques forestales. El punto de vista de la simulación computacional - Romero Castro, Aldo Humberto; Lacasta Palacio, Ana María; Lopez Moreno, Sinhue
Peer Reviewed

45604. Dispersionless transport in a washboard potential - Lindenberg, K.; Sancho, Jose Maria; Lacasta Palacio, Ana María; Sokolov, Igor M.
We study and characterize a new dynamical regime of underdamped particles in a tilted washboard potential. We find that for small friction in a finite range of forces the particles move essentially nondispersively, that is, coherently, over long intervals of time. The associated distribution of the particle positions moves at an essentially constant velocity and is far from Gaussian-like. This new regime is complementary to, and entirely different from, well-known nonlinear response and large dispersion regimes observed for other values of the external force.

45605. Characterization of the performance of an injector for the controlled generation of microbubbles - Arias Calderón, Santiago; González Cinca, Ricardo; Ruiz, Xavier; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume
We perform a characterization of a recently reported microbubble injector in conditions relevant to microgravity. Injection of bubbles is based on the generation of a slug flow in a capillary T-junction, whose operation is robust to changes in the gravity level. We address questions regarding the performance under different working regimes. In particular, we focus on the regimes found within a large range of gas and liquid injection flow rates. The injection performance is characterized by measuring bubble generation frequency. We propose curves obtained empirically for the behavior of generation frequency and crossover between regimes.

45606. Experimental study of a microchannel bubble injector for microgravity applications - Arias Calderón, Santiago; Ruiz, Xavier; Casademunt, Jaume; Ramírez de la Piscina Millán, Laureano; González Cinca, Ricardo
We perform a quantitative characterization of a microbubble injector in conditions relevant to microgravity. The injector pregenerates a slug flow by using a capillary T-junction, whose operation is robust to changes in gravity level. We address questions regarding the performance under different injection conditions. In particular we focus on the variation of both gas and liquid flow rates. The injection performance is characterized by measuring bubble injection frequency and bubble sizes. We obtain two distinct working regimes of the injector and identify the optimal performance as the crossover region between them.

45607. Experimental analysis of bubble jets collision - Suñol Galofre, Francesc Xavier; González Cinca, Ricardo
Peer Reviewed

45608. Propiedades físicas y mecánicas de los agregados reciclados de concreto - Gómez Soberón, José Manuel Vicente; Agulló Fité, Luís; Vázquez Ramonich, Enric
Las propiedades a largo plazo, como la contracción y fluencia, de los concretos reciclados(CR) presentan algunas variaciones con los concretos usuales. Dichas variaciones son interpretadas por las diferencias de densidad, porosidad y absorción de los agregados reciclados procedentes de concreto (ARC), dada su constitución de carácter parcial. En este trabajo se presenta el análisis experimental de especimenes de CR con reemplazo de agregados naturales por ARC. Se proporcionan y discuten las propiedades de los agregados empleados; así como tópicos de CR, tales como, compresión simple, tensión indirecta, módulo de elasticidad, contracción y fluencia (básicas y por secado). Los especimenes de prueba...

45609. Structural evolution of metallic glasses during annealing through in-situ Synchrotron X-ray diffract - Pineda Soler, Eloi; Boneu, Francesc; Bruna Escuer, Pere; Pradell Cara, Trinitat; Labrador, Ana; Crespo Artiaga, Daniel
In this work we study the structural evolution of Al and Fe based metallic glass compositions. The samples were obtained as ribbons by melt-spinning, their glass stability and crystallization were analyzed by calorimetry and dilatometry, structural changes were followed by in-situ synchrotron X-ray diffraction during annealing throughout glass transition and crystallization. The synchrotron results are compared with calorimetric and dilatometric measurements and the structural changes occurred during annealing are determined and described for each alloy.

45610. Fragility and glass-forming ability of the Ca-Mg-Cu system - Pineda Soler, Eloi; Zhang, Yi; Greer, A. L.
Elastic moduli of the glass and fragility of the corresponding supercooled liquid were found to be correlated in recently published results. In the present work, compositions within the Ca–Mg–Cu system are used to study the relationships between liquid fragility, glass-forming ability and elastic properties. The correlation between liquid fragility and elastic properties already observed for glasses in general is found to hold in this particular system. More extensive work should be done in order to obtain conclusive results. However, if such a correlation turns out to be general in metallic systems, it will be a powerful criterion in choosing candidate compositions for new bulk...

45611. Temporal evolution of the domain structure in a Poisson-Voronoi transformation - Pineda Soler, Eloi; Crespo Artiaga, Daniel
The temporal evolution of the domain size and free boundary distributions is calculated for a Poisson–Voronoi transformation. In this kind of transformation a set of randomly distributed domain seeds start growing simultaneously, all with equal isotropic growth rate, occupying the original untransformed space. At the end of the transformation, all the space is occupied and the final configuration is the well-known Poisson–Voronoi tessellation. In this work, the temporal evolution of the domain structure in a twodimensional transformation is obtained by means of a calculation method presented recently (Pineda et al 2007 Phys. Rev. E 75 040107(R)). The method is based on the differentiation of the domains through their number...

45612. Higher order colored noise effects in multivariable systems. - Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria
We extend the partial resummation technique of Fokker-Planck terms for multivariable stochastic differential equations with colored noise. As an example, a model system of a Brownian particle with colored noise is studied. We prove that the asymmetric behavior found in analog simulations is due to higher-order terms which are left out in that technique. On the contrary, the systematic τ-expansion approach can explain the analog results.

45613. Analysis of turbulence in fog episodes - Terradellas, Enric; Ferreres Soler, Enriqueta; Soler, M. R.
Many processes interact in a complex and highly non-linear way during the life cycle of fog, the turbulent transport being among them. Observations and analysis of urbulence are, then, fundamental to our understanding of the physical mechanisms involved with fog formation, evolution and dissipation. Data gathered by fast-response sonic anemometers are processed using wavelet methods in order to estimate turbulence parameters such as kinetic energy or fluxes during the successive stages of fog evolution.

45614. Numerical study of the generation and dispersion of a bubble jet in microgravity - Bitlloch, Pau; Carrera, Jordi; Ruiz, Xavier; González Cinca, Ricardo; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume
Peer Reviewed

45615. Experimental setup for the study of jet interactions - Suñol Galofre, Francesc Xavier; Pino, Ramón M.; Maldonado, Oscar; González Cinca, Ricardo
Peer Reviewed

45616. Experimental study of bubbles behaviour - Suñol Galofre, Francesc Xavier; Pino, Ramón M.; Maldonado, Oscar; González Cinca, Ricardo
Peer Reviewed

45617. Dynamics and statistics of a microbubble jet in microgravity - Bitlloch, Pau; Carrera, Jordi; Ruiz, Xavier; González Cinca, Ricardo; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume
Peer Reviewed

45618. Setup design and ground investigation for a microgravity experiment on bubble dynamics and coalescence - Suñol Galofre, Francesc Xavier; Pino, Ramón M.; Maldonado, Oscar; González Cinca, Ricardo
Peer Reviewed

45619. Characterization of a microbubble injector for applications in microgravity - Arias Calderón, Santiago; Ruiz, Xavier; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume; González Cinca, Ricardo
Peer Reviewed

45620. Design analysis of an experiment of bubble coalescence in microgravity - Suñol Galofre, Francesc Xavier; Pino, Ramón M.; Maldonado, O.; González Cinca, Ricardo
Peer Reviewed

 

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