Concentração de sais da soluçtiao avaliada pela condutividade elétrica na zona radicular do crisântema sob irrigação por gotejamento

The effects of salt concentration levels in electrical conductivity (EC) were evaluated in chrysanthemum root, cultivated in substrate using two sampling methods, under greenhouse conditions. The experiment was carried out in Paranapanema, São Paulo using the experimental design in randomized blocks and four replications. The treatments consisted of eight sampling periods of substrate solutions in pots: 7, 14, 21, 28, 35, 42, 49 and 56 days after strike root and five salt concentration levels of applied saline solution: 1.42; 1.65; 1.89; 2.13 and 2.36 dS m -1 in the vegetative period and during the reproduction period of flower budding: 1.71; 1.97; 2.28; 2.57 and 2.85 dS m -1. The substrate solution EC monitoring was done using two methods: solution extractors and 1:2 water diluted solution. The use of solution extractors and 1:2 water diluted solution allowed substrate solution EC monitoring along the culture cycle; the amount of salt concentration applied in the substrate caused the substrate salinity increase; the method using solution extractors presented higher EC values in the substrate.

Emprego da sondagem elétrica vertical com o método da eletroresistividade no estudo do lixão de Macapá-Ap

Vertical electrical soundings using eletroresistivity method were carried out in the public waste landfill in Macapá - AP, having as a goal to investigate the geoelectrical and hidrogeologic characteristics of the ground. The results of geophysics interpretation allowed obtaining a model of five geoelectrical layers until the depth of 14,6 m. This model is correlated to a sedimentary sequence of clay-silt-sandy with laterite. The main flow of the water table, also determined, is concordant to the topographical gradient.

Variação temporal da resistividade elétrica em contaminação por gasolina

The definition of models and base parameters for application of investigation tools in environment with high complexity are a basic premise to any sciences. The geophysics is a science with solid theoretical base and applications in diversified areas of the sciences geological, astronomical, meteorological, among many others. Its application in environmental studies is relatively recent and needs further research. To understand the behavior of resident contaminants in a dynamic and complex environment as the geological, it requests studies in scale laboratorial, under control of factors seasonality variable. This work simulates a leak of gasoline in soil, under conditions and in laboratory scale, with the objective of monitoring the temporary behavior of the hydrocarbon under the optics of variation of the parameter physical electric resistivity. The results indicate increase of the resistivity in recent periods the contamination, followed for stability in the values and finally fall and return tendency to the natural conditions.

Consumo e custo de energia elétrica na cultura de citros irrigado por gotejamento e microaspersão, com três lâminas de água

The objective of this work was to analyze the consumption, electric energy cost, and economic results of irrigated citrus (Citrus sinensis). The treatments consisted of a dripping irrigation system with one and two lateral distribution lines, a micro sprinkler irrigation system and a treatment without irrigation. For each irrigation system, three water depths were used: 100%, 75% and 50% of Etc (citrus evapotranspiration). The electric energy cost for two tariff groups, Group A and Group B, was studied. For Group A, the expenses with energy were determined for the Conventional Binomial Structure tariff, the Hour-seasonal tariff (green and blue) and the special tariff for nocturnal irrigation. The kWh cost for the tariff systems were obtained from the website of CPFL (São Paulo State Power and Light Company, Brazil). The best relation between the electric energy consumption (kWh.ha -1) and productivity (t.ha -1) occurred in the treatment irrigated with 50% of the Etc. The irrigated treatments increased productivity. The biggest productivity was observed in the irrigation treatments with 50% of the Etc when compared to the ones with 100% of the Etc. The blue and green Hour-seasonal tariff system of Group A (nocturnal irrigation) was the best option. A biggest economic turnover occurred in the treatments irrigated with 50% of the Etc.

Microgeração de energia elétrica (Abaixo de 100 kW) utilizando turbina Tesla modificada

An economical electricity generating system is developed, i.e., a boiler and turbine with a capacity ≤ 100 kw, to occupy a niche market where the existing steam systems are not economically viable. A Tesla turbine is used. It has been modified to provide greater torque, outperforming the deficiency inherent in the original Tesla turbine. It can operate with saturated steam produced by a boiler heated by biomass, gas, biodiesel, etc. The microgenerator consumes locally available fuel and can bring energy to millions of rural living Brazilians, where some kind of biomass is abundant. The Tesla turbine is compact, has no moving parts, and has endless application possibilities. A prototype system is also created to produce electricity with a boiler and generator.

Testes de envelhecimento acelerado e de condutividade elétrica em sementes de Dictyoloma vendellianum A. Juss.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistema especialista para a monitoração do processo de degradação de medidores tipo indução de energia elétrica ativa

This paper presents a methodology and software for hazard rate analysis of induction type watt-hour meters, considering the main variables related with the degradation process of these meters, for the Elektro Electricity and Services SA. The modeling developed to calculate the watt-hour meters hazard rate was implemented in a tool through a user friendly platform, in Delphi language, enabling not only hazard rate analysis, but also a classification by risk range, localization of installation for the analyzed meters, and, allowing, through an expert system, the sampling of induction type watt-hour meters, based on the model risk developed with artificial intelligence, with the mainly goal of follow and manage the process of degradation, maintenance and replacement of these meters. © 2010 IEEE.

Conversor CA-CA de elevado fator de potência para aplicações com geradores de Ímã permanente

This paper proposes and describes a high power factor AC-AC converter for naval applications using Permanent Magnet Generator (PMG). The three-phase output voltages of the PMG vary from 260 Vrms (220 Hz) to 380 Vrms (360 Hz), depending on load conditions. The proposed converter consists of a Y-/ΔY power transformer, which provides electrical isolation between the PMG and remaining stages, and a twelve-pulse uncontrolled rectifier stage directly connected to a single-phase inverter stage, without the use of an intermediary DC-DC topology. This proposal results in more simplicity for the overall circuitry, assuring robustness, reliability and reduced costs. Furthermore, the multipulse rectifier stage is capable to provide high power factor and low total harmonic distortion for the input currents of the converter. The single-phase inverter stage was designed to operate with wide range of DC bus voltage, maintaining 120 Vrms, 60 Hz output. The control philosophy, implemented in a digital signal processor (DSP) which also contains protection routines, alows series connections between two identical converters, achieving 240 Vrms, 60 Hz total output voltage. Measured total harmonic distortion for the AC output voltage is lower than 2% and the input power factor is 0.93 at 3.6kW nominal load. © 2010 IEEE.

Utilização de resíduos e derivados de madeira para confecção de uma guitarra elétrica

The residues generation is a quite serious problem in several industrial areas and also in the lumbering area. The search for the elimination or reduction of the volume of generated residues is endless, however limited, resulting in the search for a proper destination or better use, instead of simply burning it. A lot of uses and services are commonly proposed, but with low aggregated value to the residue. This work shows the usage viability of different discarded residues and wood composites in the production of an electric guitar. Cupiúba, ipê and jatobá residues have been used besides wood composites of pinus. The residues and wood composites have shown appropriate resistance, surfacing quality and design terms, and could be used to substitute the traditionally wood used in the production of the instrument as well as in other products of similar characteristics and with larger aggregated value.

Estimativa do tempo de produção de chorume em aterro controlado por meio de medidas de resistividade elétrica

Landfill is an engineering work that aims at to accommodate residues in the smallest possible space in the soil, with minimum damages to the environment and the public health. One in the constructive forms of a controlled landfill is the excavation of ditches with appropriate dimensions, for disposition of solid residues without compactation or impermeabilization. Liquid effluents generated for similar volumes of residues, disposed in ditches with ages different from closing, it should result in physical and chemical alterations you correlated at the time of residence materials. With base in this hypothesis, measures of electric resistivity were accomplished through the of Eletrical Resistivity geophysical method, on residues ditches closed annually between 12/2001 and 12/2007, localized in control landfill of the Cordeirópolis city (SP). The leachate is a liquid effluent generated by the decomposition of organic matter and characterized by high content in total dissolved solids, whose interaction with geological environment results in alterations in terms of electrical resistivity susceptible to detection for the geophysical instrumental. The results suggest a resistivity reduction for leachate percolation produced for ditches recently and increase progressive of the resistivity for older ditches. The statistical comparative analysis with reference values for the area suggests ages of the finish production and percolation leachate for soil and rock below the ditches.

Fluxo de potência trifásico probabilístico para redes de distribuição usando o método de estimação por pontos

In this paper the point estimation method is applied to solve the probabilistic power flow problem for unbalanced three-phase distribution systems. Through the implementation of this method the probability distribution functions of voltages (magnitude and angle) as well as the active and reactive power flows in the branches of the distribution system are determined. Two different approaches of the point estimation method are presented (2m and 2m+1 point schemes). In order to test the proposed methodology, the IEEE 34 and 123 bus test systems are used. The results obtained with both schemes are compared with the ones obtained by a Monte Carlo Simulation (MCS).

Estimulação elétrica neuromuscular na reabilitação da disfagia orofaríngea neurogênica

Objective. To present an overview of the literature about the efficacy of neuromuscular electrical stimulation (NMES) in the rehabilitation of neurogenic oropharyngeal dysphagia and to compare methods of therapy in stroke. Method. An extensive bibliographic survey of several databases (Medline, Scielo Brazil, Chile and Spain and Lilacs) was performed using the following keywords: deglutition disorders, therapy, electrical stimulation, pharynx and stroke between 1990 and 2011. Results. The articles reported the use of NMES in heterogeneous population; there is no consensus thus far about the method used during the NMES and about its rehabilitation efficacy in neurogenic oropharyngeal dysphagia. Conclusions. After this study, we concluded that further investigations are necessary with homogeneous groups of patients with neurogenic dysphagia, discussing the proposition of a specific NMES protocol for the rehabilitation of neurogenic oropharyngeal dysphagia.

Condutividade elétrica da solução nutritiva e acúmulo de macro e micronutrientes no cultivo de crisântemo

The study of growth and uptake of nutrients is important to determine the times of increased demand in order to schedule the fertigation. The present research was developed with the objective of evaluating the effects of different levels of electrical conductivity on growth and accumulation of nutrients in chrysanthemum plants under greenhouse conditions. The electrical conductivity levels on the applied solution were 1.42, 1.65, 1.89, 2.13 and 2.36 dS m-1 (bud vegetative stage); 1.71, 1.97, 2.28, 2.57 and 2.85 dS m-1 (bud stage). The dry mass of the aerial portion of the plant and the contents of macronutrients and micronutrients were determined every 14 days. The nutrient accumulation in chrysanthemum plant showed similar trend as compared to dry matter accumulation. The nutrients presented the following order of absorption: K>N>Ca>Mg>P>S (1425, 892, 184, 150, 110 and 59 mg plant-1) and Fe>Zn>B>Mn>Cu (2254, 2219, 1725, 1287, 210 μg plant-1). The content of most nutrients increased with increase in electrical conductivity of the solution, without salt effect up to EC of 2.85 dS m-1.

Predição da potência aeróbia (VO 2máx) de crianças e adolescentes em teste incremental na esteira rolante

The maximal oxygen uptake (VO2max) is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO 2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO 2max: VO2max (ml/min) = -1574.06 + (141.38 x Vpeak) + (48.34 * Body mass), with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min) and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.