MnO2 influence on the electrical properties of SnO2-based ceramic systems

Tin dioxide is an n-type semiconductor that when doped with other metallic oxides exhibits non-linear electric behavior with high non-linear coefficient values typical of a varistor. In this work, electrical properties of the SnO2.CoO.Ta2O5 and SnO2.CoO.MnO2.Ta2O5 ceramics systems were studied with the objective of analyzing the influence of MnO2 on sintering behavior and electrical properties of these systems. The compacts were prepared by powder mixture process and sintered at 1300°C for 1 hour, in air, using a constant heating rate of 10°C/min. The morphological and structural properties were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The densities of the sintered ceramics were measured using the Archimedes method. The SnO2.CoO.Ta2O5 and SnO2.CoO.MnO2.Ta2O5 systems presented breakdown fields (Eb) about 3100 V.cm-1 and 3800 V.cm-1, respectively, and non-linear coefficient (α) about 10 and 20, respectively.

Experimental analysis of the effect of the structure area on the PZT-based SHM systems

The structural health monitoring (SHM) systems based on electromechanical (E/M) impedance technique have been widely investigated. Although many studies indicate the reliability of this technique, some practical considerations still have to be considered in real applications. This paper presents an experimental analysis of the effect of the structure area on the system's performance. The results indicate that the sensitivity of the system to detect damage decreases significantly when the host structure has large cross-section area. Copyright © 2009 by ASME.

Mobile application as a tool for urban traffic data collection and generation to advanced traveler information systems using Wi-Fi networks available in urban centers

This paper presents an Advanced Traveler Information System (ATIS) developed on Android platform, which is open source and free. The developed application has as its main objective the free use of a Vehicle-to- Infrastructure (V2I) communication through the wireless network access points available in urban centers. In addition to providing the necessary information for an Intelligent Transportation System (ITS) to a central server, the application also receives the traffic data close to the vehicle. Once obtained this traffic information, the application displays them to the driver in a clear and efficient way, allowing the user to make decisions about his route in real time. The application was tested in a real environment and the results are presented in the article. In conclusion we present the benefits of this application. © 2012 IEEE.

Microcomputer technology to extend the use of population data in developing countries: multidisciplinary databases, Geographic Information Systems and REDATAM

Includes bibliography

On the Chaotic Suppression of Both Ideal and Non-ideal Duffing Based Vibrating Systems, Using a Magnetorheological Damper

In this paper the dynamics of the ideal and non-ideal Duffing oscillator with chaotic behavior is considered. In order to suppress the chaotic behavior and to control the system, a control signal is introduced in the system dynamics. The control strategy involves the application of two control signals, a nonlinear feedforward control to maintain the controlled system in a periodic orbit, obtained by the harmonic balance method, and a state feedback control, obtained by the state dependent Riccati equation, to bring the system trajectory into the desired periodic orbit. Additionally, the control strategy includes an active magnetorheological damper to actuate on the system. The control force of the damper is a function of the electric current applied in the coil of the damper, that is based on the force given by the controller and on the velocity of the damper piston displacement. Numerical simulations demonstrate the effectiveness of the control strategy in leading the system from any initial condition to a desired orbit, and considering the mathematical model of the damper (MR), it was possible to control the force of the shock absorber (MR), by controlling the applied electric current in the coils of the damper. © 2012 Foundation for Scientific Research and Technological Innovation.

Workshop on Caribbean energy information systems

Presenta el resumen del informe y las recomendaciones del taller que tuvo como objetivo estudiar las posibilidades para establecer un sistema de informacion en energia en el Caribe.

Caribbean network of regional information systems

Analiza algunos de los puntos tratados en el documento sobre una estrategia del Sistema Regional de Informacion para el Caribe en el ano 2000 (WP/RIS/L.87/1) y que fue discutido posteriormente en una reunion de expertos que se realizo en Puerto Espana entre el 27-29 de mayo de 1987. Sugiere un mecanismo que permita monitorear, perfeccionar y coordinar futuras actividades que aseguren un desarrollo racional de los sistemas regionales de informacion del Caribe.

Reunión Microcomputación y Sistemas de Información Documentales en América Latina: Problemas, Experiencias y Proyecciones = Meeting Microcomputers and Bibliographic Information Systems in Latin America: Problems, Experiences and Projections

Contiene objetivos, conclusiones y recomendaciones de la Reunion sobre Microcomputacion y Sistemas de Informacion Documentales en America Latina: Problemas, Experiencias y Proyecciones. Incluye ademas, lista de participantes y de siglas de instituciones, redes de informacion y paquetes de programas; resumenes de trabajos presentados; caracteristicas de paquetes de programas revisados y lista de documentos presentados.

Evaluation of management information systems for maternal child health

Includes bibliography

Evaluation of Management Information Systems for Maternal Child Health

El informe resume los resultados de un proyecto (UNFPA/CELADE/PAHO) destinado a evalur los sistemas de informacion administrativos de los programas materno-infantiles y de planificacion familiar en 10 paises de la region. La primera parte describe los principales hallazgos en terminos de los problemas comunes identificados y que son de caracter interinstitucional, organizativo, relativos a los datos, operacionales y de recursos. La segunda parte presenta en forma resumida las evaluaciones por paises y en la tercera se incluyen los informes finales de los evaluadores.

Public health information systems in the Caribbean

Includes bibliography

Uma arquitetura multiagentes para sistema educacional baseado na web semântica

Pós-graduação em Ciência da Computação - IBILCE