Método de análisis para determinar el contenido de humedad adecuado para la obtención de resistencias en fachadas trasventiladas de piedra natural sometidas al agua de lluvia.

El artículo muestra la influencia que tiene la consideración del contenido de humedad en el diseño de las fachadas trasventiladas hechas de piedra natural porosa. Se comprueba cómo este factor influye en la resistencia de las placas y condiciona sus dimensiones. Por ello se propone realizar un análisis más amplio del comportamiento frente al agua, que el propuesto por las normas EN. A través de un ejemplo, se muestra cómo realizar dicho análisis y se dan pautas para elegir un contenido de humedad que represente el grado de absorción que la piedra pueda alcanzar en este tipo de fachadas. Con este contenido, se determinarán las resistencias mecánicas de las placas. El estudio se ha aplicado a tres areniscas de la misma zona del noreste español, obteniendo resultados que demuestran la utilidad del análisis que se propon

Weak localization competes with the quantum oscillations in a natural electronic superlattice: the case of Na1.5(PO2)4(WO3)20

We report an investigation of the combined structural and electronic properties of the bronze Na1.5 (PO2 )4 (WO3 )20 . Its low-dimensional structure and possible large reconstruction of the Fermi surface due to charge density wave instability make this bulk material a natural superlattice with a reduced number of carriers and Fermi energy. Signatures of multilayered two-dimensional (2D) electron weak localization are consequently reported, with an enhanced influence of quantum oscillations. A crossover between these two antagonistic entities, previously observed only in genuine low-dimensional materials and devices, is shown to occur in a bulk crystal due to its hidden 2D nature

Persistent spins in the linear diffusion approximation of phase ordering and zeros of stationary gaussian processes

The fraction r(t) of spins which have never flipped up to time t is studied within a linear diffusion approximation to phase ordering. Numerical simulations show that, even in this simple context, r(t) decays with time like a power-law with a non-trival exponent $\theta$ which depends on the space dimension. The local dynamics at a given point is a special case of a stationary gaussian process of known correlation function and the exponent $\theta$ is shown to be determined by the asymptotic behavior of the probability distribution of intervals between consecutive zero-crossings of this process. An approximate way of computing this distribution is proposed, by taking the lengths of the intervals between successive zero-crossings as independent random variables. The approximation gives values of the exponent $\theta$ in close agreement with the results of simulations.Comment: 10 pages, 2 postscript files. Submitted to PRL. Reference screwup correcte

Collective dynamics of liquid aluminum probed by Inelastic X-ray Scattering

An inelastic X-ray scattering experiment has been performed in liquid aluminum with the purpose of studying the collective excitations at wavevectors below the first sharp diffraction peak. The high instrumental resolution (up to 1.5 meV) allows an accurate investigation of the dynamical processes in this liquid metal on the basis of a generalized hydrodynamics framework. The outcoming results confirm the presence of a viscosity relaxation scenario ruled by a two timescale mechanism, as recently found in liquid lithium.Comment: 8 pages, 7 figure

Maternal effects on anogenital distance in a wild marmot population

Peer reviewedPublisher PD

Work, free energy and dissipation in voltage driven single-electron transitions

We apply the general procedure presented by Jarzynski in [1] to the problem of dissipation in a voltage-driven single-electron box. We obtain the expression of dissipated work, and find its relation to the dissipation Q obtained in [2]. We show that the two quantities are identical in common gate protocols where the system makes a transition for sure

Subdiffusion-limited reactions

We consider the coagulation dynamics A+A -> A and A+A A and the annihilation dynamics A+A -> 0 for particles moving subdiffusively in one dimension. This scenario combines the "anomalous kinetics" and "anomalous diffusion" problems, each of which leads to interesting dynamics separately and to even more interesting dynamics in combination. Our analysis is based on the fractional diffusion equation

A Method of Intervals for the Study of Diffusion-Limited Annihilation, A + A --> 0

We introduce a method of intervals for the analysis of diffusion-limited annihilation, A+A -> 0, on the line. The method leads to manageable diffusion equations whose interpretation is intuitively clear. As an example, we treat the following cases: (a) annihilation in the infinite line and in infinite (discrete) chains; (b) annihilation with input of single particles, adjacent particle pairs, and particle pairs separated by a given distance; (c) annihilation, A+A -> 0, along with the birth reaction A -> 3A, on finite rings, with and without diffusion.Comment: RevTeX, 13 pages, 4 figures, 1 table. References Added, and some other minor changes, to conform with final for