775 research outputs found
Unimodular cosmology and the weight of energy
Some models are presented in which the strength of the gravitational coupling
of the potential energy relative to the same coupling for the kinetic energy
is, in a precise sense, adjustable. The gauge symmetry of these models consists
of those coordinate changes with unit jacobian.Comment: LaTeX, 23 pages, conclusions expanded. Two paragraphs and a new
reference adde
Intervención sobre la suma mediante el uso combinado de regletas y TIC’s
Se trata de una investigación empírico-cuantitativa que pretende comprobar que las claves de Driver y Bell (1986) sobre aprendizaje manipulativo y significativo son efectivas para el aprendizaje de la suma en alumnos de 4º de Primaria que presentan dificultades de aprendizaje (Radatz, 1979, 1980). Esta intervención se realizó en el último semestre del curso 2014/2015 en el colegio de la Asunción de Ponferrada. El grupo-clase está formado por 25 alumnos (14 niñas y 11 niños) de 4º de Primaria en donde se aprecia en general déficit de atención, acentuado en tres alumnos, uno de ellos diagnosticado
Experimental and predicted vapour-liquid equilibrium of the binary mixtures n-heptane + chlorobutane isomers
The study of the isothermal vapour-liquid equilibrium (VLE) of the binary mixtures n-heptane plus chlorobutane isomers (1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane or 2-chloro-2-methylpropane) at three different temperatures, T = 288.15, 298.15 and 308.15 K, is presented in this contribution. The experimental results were correlated using Wilson equation and the thermodynamic consistency of the data was checked by the van Ness method. Furthermore, two different methods have been used to predict the phase equilibrium in isothermal conditions: a pure group contribution method (modified-UNIFAC) and a group contribution equation of state (VTPR)
Solving Logistic-Oriented Bin Packing Problems Through a Hybrid Quantum-Classical Approach
The Bin Packing Problem is a classic problem with wide industrial
applicability. In fact, the efficient packing of items into bins is one of the
toughest challenges in many logistic corporations and is a critical issue for
reducing storage costs or improving vehicle space allocation. In this work, we
resort to our previously published quantum-classical framework known as
Q4RealBPP, and elaborate on the solving of real-world oriented instances of the
Bin Packing Problem. With this purpose, this paper gravitates on the following
characteristics: i) the existence of heterogeneous bins, ii) the extension of
the framework to solve not only three-dimensional, but also one- and
two-dimensional instances of the problem, iii) requirements for item-bin
associations, and iv) delivery priorities. All these features have been tested
in this paper, as well as the ability of Q4RealBPP to solve real-world oriented
instances.Comment: 7 pages, 7 figures, paper accepted for being presented in the
upcoming 26th IEEE International Conference on Intelligent Transportation
Systems - ITSC 202
Resonance fluorescence spectrum of a \Lambda-type quantum emitter close to a metallic nanoparticle
We theoretically study the resonance fluorescence spectrum of a three-level quantum emitter coupled to a spherical metallic nanoparticle. We consider the case that the quantum emitter is driven by a single laser field along one of the optical transitions. We show that the development of the spectrum depends on the relative orientation of the dipole moments of the optical transitions in relation to the metal nanoparticle. In addition, we demonstrate that the location and width of the peaks in the spectrum are strongly modified by the exciton-plasmon coupling and the laser detuning, allowing to achieve controlled strongly subnatural spectral line. A strong antibunching of the fluorescent photons along the undriven transition is also obtained. Our results may be used for creating a tunable source of photons which could be used for a probabilistic entanglement scheme in the field of quantum information processing
The ignition and anchoring of diffusion flames by triple flames
The enhancement effects of thermal expansion on the propagation velocity of triple flames in mixing layers have been evaluated by direct numerical simulation of the Process.
Numerical calculations have been used for the description of the flow, concentration and temperature field in the diffusion flame attachment region in the near wake of the injector. The numerical analysis provides the criterium for lift-off of the flames
Thermophysical study of 2-acetylthiophene: experimental and modelled results
Several thermophysical properties have been studied for 2-acetylthiophene: (i) vapour pressure was determined at temperatures within 336.16–445.02 K; (ii) density, speed of sound, static permittivity, refractive index, surface tension, and kinematic viscosity were measured at p = 0.1 MPa and at temperatures from 278.15 K (or 283.15 K for the refractive index) to 338.15 K; (iii) volumetric properties were also determined at temperatures in the (283.15–338.15) K range and at pressures up to 65.0 MPa. From these experimental values, different derivative properties have been calculated such as enthalpy of vaporization, isobaric expansibility, isothermal and isentropic compressibility, dipole moment, entropy and enthalpy of surface formation, and dynamic viscosity. All experimental properties were correlated and the results were explained through the intermolecular interactions. Moreover PC-SAFT EoS was used to model the thermodynamic behaviour of the compound. Finally, this EoS combined with the Density Gradient Theory allowed obtaining the influence parameter for the surface tension of 2-acetylthiophene
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