Operational safety: Development of electronic system for dynamic balance evaluation of farm tractors

The present study aimed at the development and evaluation of a low cost electronic device in order to provide safety for farm tractor users. The major accident occurrence in agricultural surroundings is from farm tractor side bending. Therefore, this sensor was designed to detect and alert about it. The results were satisfying. © 2013 Taylor & Francis Group.

Proposta metodológica para avaliação de controlador automático de seções e pulverização

Na aplicação de produtos fitossanitários, a utilização de equipamentos que controlam automaticamente as seções da barra e a pulverização já é realidade; entretanto, ainda não há resultados que demonstrem a sua eficácia. Por esse motivo, este trabalho teve por finalidade desenvolver uma metodologia para a avaliação de um equipamento que controla automaticamente as seções e a pulverização. Avaliou-se um controlador automático de seções e pulverização de mercado, e, para tanto, foram utilizados três níveis de acurácia do sinal de GPS (algoritmo interno, SBAS e RTK), três ângulos para a simulação de entrada e saída da barra de pulverização em relação à borda do talhão (0; 45 e 60º ) e três velocidades de trabalho (1,66; 5,00 e 8,33 m s-1). A metodologia proposta possibilitou a determinação dos tempos e distâncias de abertura e fechamento das seções. Os coeficientes de variação para os tempos e distâncias de abertura e fechamento das seções indicaram uma variação considerável. Houve interações significativas em função do tipo de sinal de GPS. A configuração recomendada pelo fabricante e adotada para a avaliação do controlador automático de seções e pulverização não atende a todas as situações simuladas.

Numerical and experimental analysis of natural convection in a cavity with flush mounted heat sources on a side wall

This work considers a problem of interest in several technological applications such as the thermal control of electronic equipment. It is also important to study the heat transfer performance of these components under off-normal conditions, such as during failure of cooling fans. The effect of natural convection on the flow and heat transfer in a cavity with two flush mounted heat sources on the left vertical wall, simulating electronic components, is studied numerically and experimentally. The influence of the power distribution, spacing between the heat sources and cavity aspect ratio have been investigated. An analysis of the average Nusselt number of the two heat sources was performed to investigate the behavior of the heat transfer coefficients. The results obtained numerically and experimentally, after an error analysis, showed a good agreement.

Computational tool to support design of DAC Converter model AD7528 with the object code in XML

Based on literature review, electronic systems design employ largely top-down methodology. The top-down methodology is vital for success in the synthesis and implementation of electronic systems. In this context, this paper presents a new computational tool, named BD2XML, to support electronic systems design. From a block diagram system of mixed-signal is generated object code in XML markup language. XML language is interesting because it has great flexibility and readability. The BD2XML was developed with object-oriented paradigm. It was used the AD7528 converter modeled in MATLAB / Simulink as a case study. The MATLAB / Simulink was chosen as a target due to its wide dissemination in academia and industry. From this case study it is possible to demonstrate the functionality of the BD2XML and make it a reflection on the design challenges. Therefore, an automatic tool for electronic systems design reduces the time and costs of the design.

Plataforma para medição de forças na região plantar de pacientes normais e hemiplégicos

This work describes an electronic system implementation with two force plates, 24 load cells with strain gages, signal conditioning circuit, interfacing circuit and data acquisition system, designed for measuring plantar force distribution in patients. The system presented linear response, low hysteresis, with determination coefficient of 0.9997, precision better than 0,84% and resolution less than 0.5 N. The Measurements are presented on a computer screen and easier visualization to specialists, mainly physicians, physiotherapists and occupational therapists. Using the system, the distribution of weight in the plantar region of 100 normal subjects and 10 hemiplegic patients was investigated. There were determined the relationship between weight distribution on the right and left forefoot, hemiplegic patients and normal patients, with the implemented system. © 2013 Springer.

Design instrucional: uma abordagem do design gráfico para o desenvolvimento de ferramentas de suporte à Educação a Distância

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistema eletrônico para geração e avaliação de movimentos em paraplégicos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise experimental e desenvolvimento de um modelo numérico simplificado para um trocador de calor compacto para resfriamento de componentes eletrônicos

Pós-graduação em Engenharia Mecânica - FEIS

Desenvolvimento experimental e simulação numérica de uma réplica térmica de placa de circuito impresso

Pós-graduação em Engenharia Mecânica - FEIS

Analysis of the influence of baffles and shields on the cooling of a digital transmission equipment

In this work design criteria for cooling of electronic systems used in a digital transmission equipment are considered. An experimental study using a simulated electronic equipment in which vertically oriented circuit boards are aligned to form vertical channels is carried out. Resistors are used to simulate actual components. The temperature of several components in the printed circuit boards are measured and the influence of the baffles and shields on the cooling effect are discussed. It was observed that the use of the baffles reduce the temperature levels and, the use of shields, although protecting the components from magnetic effects, cause an increase in the temperature levels.

Monitoramento de integridade estrutural e de sistemas utilizando dispositivos de baixo custo

Pós-graduação em Engenharia Mecânica - FEB

Desenvolvimento de dispositivos computacionais para registro de dados pluviométricos e análise operacional de pluviômetros basculantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coupling Surface-Enhanced Resonance Raman Scattering and Electronic Tongue as Characterization Tools to Investigate Biological Membrane Mimetic Systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electronic ballast for multiple fluorescent lamp systems

An electronic ballast for multiple tubular fluorescent lamp systems is presented. The proposed structure has a high value for the power factor, a dimming capability, and soft switching of the semiconductor devices operated at high frequencies. A zero-current switching pulse width modulated SEPIC converter is used as the rectifying stage and it is controlled using the instantaneous average input current technique. The inverting stage consists of classical resonant half-bridge converter with series-resonant parallel-loaded filters. The dimming control technique is based on varying the switching frequency and monitoring the phase shift of the current drained by the filters and lamps in order to establish a closed loop control. Experimental results are presented that validate the theoretical analysis.

Density functional theory study on the structural and electronic properties of low index rutile surfaces for TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 composite systems

The present study is concerned with the structural and electronic properties of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 composite systems. Periodic quantum mechanical method with density functional theory at the B3LYP level has been carried out. Relaxed surface energies, structural characteristics and electronic properties of the (I 10), (0 10), (10 1) and (00) low-index rutile surfaces for TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 models are studied. For, comparison purposes, the bare rutile TiO2 and SnO2 structures are also analyzed and compared with previous theoretical and experimental data. The calculated surface energy for both rutile TiO2 and SnO2 surfaces follows the sequence (110) < (010) < (101) < (001) and the energy increases as (010) < (101) < (110) < (001) and (010) approximate to (110) < (101) < (001) for SnO2/TiO2/SnO2 and TiO2/SnO2/TiO2 composite systems, respectively. SnO2/TiO2/SnO2 presents larger values of surface energy than the individual SnO2 and TiO2 metal oxides and the TiO2/SnO2/TiO2 system renders surface energy values of the same order that the TiO2 and lower than the SnO2. An analysis of the electronic structure of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 systems shows that the main characteristics of the upper part of the valence bands for all the studied surfaces are dominated by the external layers, i.e., by the TiO2 and the SnO2, respectively, and the topology of the lower part of the conduction bands looks like the core layers. There is an energy stabilization of both valence band top and conduction band bottom for (110) and (010) surfaces of the SnO2/TiO2/SnO2 composite system in relation to their core TiO2, whereas an opposite trend is found for the same surfaces of the TiO2/SnO2/TiO2 composite system in relation to the bare SnO2. The present theoretical results may explain the growth of TiO2@SnO2 bimorph composite nanotape.