La resolución de problemas : una revisión estructurada

The aim of this paper is to review and organize the background, historic development and present situation of problemsolving research on Sciences and Mathematics

Escuchando el sonido : concepciones sobre acústica en alumnos de distintos niveles educativos

In recent years, many articles have been published on students' preconceptions of different theoretical concepts in Physics. Howewer, one area of this discipline which has received very little attention is that of Acoustics. This article first examines Acoustics from a wide range of perspectives, placing it within a scientific, didactic, and sociological framework. Secondly, it analyzes the results of a test given to students of different ages and levels in order to identify common preconceptions of Acoustics. Finally a reflection about the possible implications these might have for the Physics classroom is made

LICOR-Liquid Columns' Resonances

The aim of the experiment LICOR was the investigation of the axial resonances oi cylindrical liquid columns supported by equal circular coaxiaJ disks. In preparation ot the D-2 experiment a •heoreiical model has been developed, which exactly describes the small amplitude oscillations of finite cylindrical columns between coaxial circular disks. In addition, in terrestrial experiments the resonance frequencies of small liquid columns with up to 5 mm in diameter have been determined and investigations with density-matched liquids (silicon oil in a waierlmethanol mixture) have been performed. For the D-2 experiment LICOR the front disk and the rear disk lor use in the AFPM have been constructed and equipped with pressure sensors and the necessary electronics. The pressure exerted by the oscillating liquid column on trie supporting disks vsas as low as 10 Pa. Since the data downlink of the Materials Research Laboratory was just one signal oer second and channel, it was necessary to determine amplitude and phase of the pressure already in the LICOR disks. The D-2 experiment has been successfully performed. It has fully confirmed the theoretical models and remarkably supplements the experiments on small liquid columns and on density-matched columns

Anisotropic Atom-Surface Interactions in the Casimir-Polder Regime

The distance-dependence of the anisotropic atom-wall interaction is studied. The central result is the 1/z^6 quadrupolar anisotropy decay in the retarded Casimir-Polder regime. Analysis of the transition region between non-retarded van der Waals regime (in 1/z^3) and Casimir-Polder regime shows that the anisotropy cross-over occurs at very short distances from the surface, on the order of 0.03 Lambda, where Lambda is the atom characteristic wavelength. Possible experimental verifications of this distance dependence are discussed.Comment: 5 pages, 2 figure

Synchronization of the Frenet-Serret linear system with a chaotic nonlinear system by feedback of states

A synchronization procedure of the generalized type in the sense of Rulkov et al [Phys. Rev. E 51, 980 (1995)] is used to impose a nonlinear Malasoma chaotic motion on the Frenet-Serret system of vectors in the differential geometry of space curves. This could have applications to the mesoscopic motion of biological filamentsComment: 12 pages, 7 figures, accepted at Int. J. Theor. Phy

A teleoperated facility for variable gravity level fluid physics experimentation

A facility to perform experiments on fluid physics and specially on the mechanical behavior of liquid bridges has been designed and built. The facility consists of a velocity controlled centrifuge than can be rotated at speeds up to 10 rpm with and arm of 1.5 m where the experiment container (a Plateau tank in which different mechanical stimuli can be imposed to the liquid column) can be fixed at any location. The rotating system transmits out a video signal for diagnosis and besides control and monitoring signals are routed to the external data management system. The facility and its control system has been implemented in a way that it is possible to control and monitor the experiments either locally from a control workstation or the entire facility can enter in a mode to be controlled remotely. In this case, the control workstation is located far away the facility (indeed in a different city) and linked with data lines. The purpose of this exercise is to gain experience on the minimum data bandwidth needed and the impact on orbital platforms fluid science experimentation of transmission delays and data loses. The latter effects are implemented in the data stream in a way that can be simulated at a rate much higher than that will be experienced otherwise