The Spin-Orbit Evolution of GJ 667C System: The Effect of Composition and Other Planet's Perturbations

Potentially habitable planets within the habitable zone of M-dwarfs are affected by tidal interaction. We studied the tidal evolution in GJ 667C using a numerical code we call TIDEV. We reviewed the problem of the dynamical evolution focusing on the effects that a rheological treatment, different compositions and the inclusion of orbital perturbations, have on the spin-down time and the probability to be trapped in a low spin-orbit resonance. Composition have a strong effect on the spin-down time, changing, in some cases, by almost a factor of 2 with respect to the value estimated for a reference Earth-like model. We calculated the time to reach a low resonance value (3:2) for the configuration of 6 planets. Capture probabilities are affected when assuming different compositions and eccentricities variations. We chose planets b and c to evaluate the probabilities of capture in resonances below 5:2 for two compositions: Earth-like and Waterworld planets. We found that perturbations, although having a secular effect on eccentricities, have a low impact on capture probabilities and noth- ing on spin-down times. The implications of the eccentricity variations and actual habitability of the GJ 667C system are discussed.Comment: 15 pages, 9 figures, 4 tables. Accepted for publication in MNRAS - V

Evaluation of wind-wave generation formulations for separating wind sea and swell at the Gulf of Tehuantepec

Measurements of atmospheric and oceanographic parameters have been taken by the CICESE from an offshore location at the Gulf of Tehuantepec. The relevant features in the area are its particular meteorological and wave conditions. Due to a geographical depression of the mountain chain that goes along the isthmus a wind system ‘Tehuanos’ is formed. This wind system forces a sea that travels southwards offshore, where the wave climate is to a great extent dominated by the presence of swells that propagate typically northwards to the coast. Different methods for separating wind sea and swell have been tested. Namely (a) a constant split up frequency, (b) Drennan et al., formulation, (c) Komen et al. formulation, (d) Janssen’s theory which is the wind-wave generation mechanism of the WAM model, and (e) spectral partitioning in combination with (c). A constant split up frequency appears to be accurate in this case given that swell and wind sea systems are very well defined in the frequency domain. The use of spectral partitioning has also output satisfactory results. Inconsistencies due to the artificial splitting of the spectrum were found for methods (b), (c) and (d), for which the actual energy of the wind sea is not properly estimated. There was no substantial difference found on the energy-frequency evolution of wind seas for Tehuanos and non- Tehuanos winds

A reconfigurable FPGA-based architecture for modular nodes in wireless sensor networks

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. J. Portilla, T. Riesgo, and Á. de Castro, "A reconfigurable FPGA-based architecture for modular nodes in wireless sensor networks", 3rd Southern Conference on Programmable Logic, SPL 2007, Mar del Plata (Argentina), pp. 203 - 206A reconfigurable platform for sensor networks is presented. This platform has features that allow easy reuse of the node in several applications avoiding redesigning the system from scratch. The node includes an FPGA which is the core of the reconfiguration capabilities of the node. Several hardware interfaces for sensor standard protocols like I2C or PWM have been developed and implemented in the FPGA. Remote reconfiguration is an important feature and sensor networks can take advantage of it in order to improve the global performance

Integrated hardware interfaces for modular sensor networks

Portilla, J., de Castro, A., Abril, A., Riesgo, T., “Integrated hardware interfaces for modular sensor networks”, Proceedings of SPIE - The International Society for Optical Engineering”, 6590, 9, 2007. Copyright 2007. Society of Photo‑Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.Sensor networks have reached a great relevance during the last years. The idea is to use a large number of nodes measuring different physical parameters in several environments, which implies different research challenges (low power consumption, communication protocols, platform hardware design, etc). There is a tendency to use modular hardware nodes in order to make easier rapid prototyping as well as to be able to redesign faster and reuse part of the hardware modules. One of the main obstacles for rapid prototyping is that sensors present heterogeneous interfaces. In this paper, a VHDL library for sensors/actuators interfaces is proposed. The purpose is to have a set of different sensor interfaces that include the most common in the sensors/actuators world, enabling the rapid connection to a new sensor/actuator. Moreover, the concept presented here may be used for new interfaces that can be easily developed. The VHDL implementation is independent of the final platform (any FPGA or ASIC) in order to minimize redesign effort and make easier rapid prototyping. The interfaces are installed in a UPM platform for sensor networks

Preyssler Heteropolyacids in the Self-Etherification of 5-Hydroxymethylfurfural to 5,5′-[Oxybis(methylene)]bis-2-furfural Under Mild Reaction Conditions

The synthesis of 5,5′-[oxybis(methylene)]bis-2-furfural (OBMF) from 5-hydroxymethylfurfural (5-HMF) was studied using bulk and alumina-supported Preyssler heteropolyacids (HPAs). The formation of OBMF was related to the amount of Brønsted acid sites, and the lowest yield of OBMF was obtained with supported HPAs. However, the Lewis acidity of the HPA supported on Al2O3 favored the formation of 2,5-dimethylfurane. The effects of solvent, catalyst loading, temperature, and reaction time on the selectivity to OBMF from 5-HMF were studied to optimize OBMF production using bulk Preyssler HPAs; a yield of 84 % to OBMF was obtained at 5 h and 343 K. These results demonstrate that bulk Preyssler HPA is a good candidate for OBMF synthesis under mild reaction conditions.Fil: Páez, Alexander. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Rojas, Hugo A.. Universidad Pedagógica y Tecnológica de Colombia;Fil: Portilla Zúñiga, Omar Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Sathicq, Angel Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Afonso, Carlos A. M.. Universidade de Lisboa; PortugalFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; Colombi

A hardware library for sensors/actuators interfaces in sensor networks

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. J. Portilla, J. L. Buron, T. Riesgo, and A. de Castro, "A hardware library for sensors/actuators interfaces in sensor networks", and 13th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2006, Nice (France), 2006, pp. 1244 - 1247.Sensor networks have reached a great relevance during the last years. The idea is to use a high number of nodes measuring different physical parameters in several environments, which implies different research challenges (low power consumption, communication protocols, platform hardware design, etc). There is a tendency to use modular hardware nodes in order to make easier rapid prototyping as well as to be able to redesign faster and reuse part of the hardware modules. One of the main obstacles for rapid prototyping is that sensors present heterogeneous interfaces. In this paper, a VHDL library for sensors/actuators interfaces is proposed in order to have a set of different sensor interfaces that include the most common in the sensors/actuators world, enabling a rapid connection to a new sensor/actuator

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí