Thermal diode assisted by geometry under cycling temperature

Technological progress in electronics usually requires their use in increasingly aggressive environments, such as rapid thermal cycling and high power density. Thermal diodes appear as excellent candidates to thermally protect critical electronic components and ensure durability and reliability. We model the heat transport across a square plate with a hole subjected to an oscillating external temperature, such spatial and temporal symmetries are broken. We find rectification of the heat current that strongly depends on the frequency and the geometry of the hole. This system behaves as a thermal diode that could be used as part of a thermal architecture to dissipate heat under cycling temperature conditions.Comment: More information available here: https://sites.google.com/view/neptp-ungs-mecom2021/hom

Work - Energy theorem in rotational reference frames

En los libros de texto estándar de física universitaria, el Teorema del Trabajo y la Energía se presenta generalmente para sistemas de referencia inerciales, en los cuales está claro que la energía cinética se conserva cuando no hay trabajo neto de las fuerzas de interacción ¿Pero qué sucede cuando la energía y el trabajo se calculan en un marco de referencia no inercial? En general, en los textos básicos de física esta importante cuestión no es tratada. En este trabajo buscamos contribuir, en este aspecto, con una propuesta de actividades que permitan presentar y discutir este teorema parados como observadores en rotación relativa, haciendo hincapié explícitamente en las diferencias entre una y otra descripción. Esta propuesta tiene como objetivo la presentación gradual, mediante la discusión, de los conceptos a partir de ejemplos sencillos y prácticos, pero utilizando nociones básicas del formalismo vectorial.In standard textbooks of college physics, Theorem of Work and Energy is generally presented for inertial reference systems in which it is clear that the kinetic energy is conserved when there is not net work of the forces of interaction. But what happens when energy and work are calculated on a non-inertial reference frame? In general, in basic physics textbooks this important issue is not treated. In this paper we seek to contribute, in this respect, with a proposal of activities to present and discuss this theorem standing for observers in relative rotation, explicitly emphasizing the differences between each description. This proposal aims at a gradual introduction, by discussion of concepts from simple and practical examples, but using the basic knowledge of vector formalism.Fil: Fernández, D.M.. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Carusela, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: El Hasi, C.D.. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Lopez Arriazu, F.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentin

Recent advances on information transmission and storage assisted by noise

The interplay between nonlinear dynamic systems and noise has proved to be of great relevance in several application areas. In this presentation, we focus on the areas of information transmission and storage. We review some recent results on information transmission through nonlinear channels assisted by noise. We also present recent proposals of memory devices in which noise plays an essential role. Finally, we discuss new results on the influence of noise in memristors.Comment: To be published in "Theory and Applications of Nonlinear Dynamics: Model and Design of Complex Systems", Proceedings of ICAND 2012 (Springer, 2014

PHASE BEHAVIOR IN A RING OF STOCHASTIC OSCILLATORS

We analyze the phase response of a system shaped as a ring of overdamped bistable and noisy oscillators coupled directionally. This device, which operates in the regime of stochastic resonance, may act as a short-term memory device. In the present work we show that in this regime the system presents partial phase synchronization with an average frequency equal to the external one. For lower/greater values of noise the system becomes more/less ordered, which is characterized by a statistical measure.Noise, stochastic systems

Thermal transport in a 2D stressed nanostructure with mass gradient

Inspired by some recent molecular dynamics (MD) simulations and experiments on suspended graphene nanoribbons, we study a simplified model where the atoms are disposed in a rectangular lattice coupled by nearest neighbor interactions which are quadratic in the interatomic distance. The system has a mechanical strain, and the border atoms are coupled to Langevin thermal baths. Atom masses vary linearly in the longitudinal direction, modeling an isotope or doping distribution. This asymmetry and tension modify thermal properties. Although the atomic interaction is quadratic, the potential is anharmonic in the coordinates. By direct MD simulations and solving Fokker-Planck equations at low temperatures, we can better understand the role of anharmonicities in thermal rectification. We observe an increasing thermal current with an increasing applied mechanical tension. The temperatures and thermal currents vary along the transverse direction. This effect can be useful to establish which parts of the system are more sensitive to thermal damage. We also study thermal rectification as a function of strain and system size. Received: 20 Novembre 2014, Accepted: 17 April 2015; Edited by: C. A. Condat, G. J. Sibona; DOI: http://dx.doi.org/10.4279/PIP.070008 Cite as: R Barreto, M F Carusela, A Mancardo Viotti, A G Monastra, Papers in Physics 7, 070008 (2015

Thermal expansion in nanoresonators

Inspired by some recent experiments and numerical works related to nanoresonators, we perform classical molecular dynamics simulations to investigate the thermal expansion and the ability of the device to act as a strain sensor assisted by thermally-induced vibrations. The proposed model consists in a chain of atoms interacting anharmonically with both ends clamped to thermal reservoirs. We analyze the thermal expansion and resonant frequency shifts as a function of temperature and the applied strain. For the transversal modes the shift is approximately linear with strain. We also present analytical results from canonical calculations in the harmonic approximation showing that thermal expansion is uniform along the device. This prediction also works when the system operates in a nonlinear oscillation regime at moderate and high temperatures.Fil: Mancardo Viotti, Agustin Matias. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monastra, Alejandro Gabriel. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moreno, Mariano F.. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Carusela, María Florencia. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin