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Terra M.A.,Instituto Federal do Tocantins IFTO | Martins D.,São Paulo State University | Da Costa N.V.,West Parana State University | De Marchi S.R.,Federal University of Mato Grosso
Bioscience Journal | Year: 2014

The objective of this study was to evaluate different nozzles and spray rates on drop deposition in corn (Zea mays), Euphorbia heterophylla and Brachiaria plantaginea, both weeds located at and between crop rows. The experimental design established was complete random blocks with treatments arranged at 2 x 2 factorial scheme (2 nozzles types: DG11002VS flat flan and medium droplets, TXVK08 cone and very fine droplets; and 2 rates: 100 and 200 L ha-1) with four replications. The spray applications occurred at 13 days after corn germination (3-5 expanded leaves), when E. heterophylla and B. plantaginea plants had 2-4 and 2-3 leaves, respectively. Solution of Brilliant Blue (FD&C-1) dye at 3,000 ppm was used as spray tracer. It was concluded that the greatest average deposits in corn plants was provided by TXVK08, independently of the spray rates used. The most uniform deposits occurred when the spray rates of 200 L ha-1 was used. Spray deposits were most uniform in B. plantaginea compared to E. heterophylla when both weds were located at crop row, independently of nozzle or spray rates. However, the DG 11002VS spray nozzle provided the most uniform drop deposition on B. plantaginea located between the rows, while the most efficient deposition over E. heterophylla located between rows was TXVK08. © 2014, Association for Information Systems. All rights reserved.

da Silva Neto S.P.,Instituto Federal do Tocantins IFTO | dos Santos A.C.,Federal University of Tocantins | Leite R.L.L.,Instituto Federal do Tocantins IFTO | Dim V.P.,Doutorando UFT | And 2 more authors.
Bioscience Journal | Year: 2012

The aim of this study was to quantify and describe the spatial variability, with a view to mapping of the agronomic properties of the grass and organic matter content of soil in Brachiaria brizantha grass cultivar Marandu grown in Typic Quartzipsamment with different level of degradation. The collections of plants and soil were carried out in regular grid with distances of 5 versus 5 m area of 900 m 2. The dry mass of green leaves (MSFV), stem (MSC), dry matter (MSMM) and total dry mass (MST) and the content of soil organic matter (MOS) of pasture were analyzed for descriptive statistics, comparison of average by Tukey at 5% significance, geostatistical analyses and interpolation by ordinary kriging. Spatial heterogeneity of production MSFV, MSC, MSMM, MST and MOS were observed within and between areas of Marandu grass with low grade, middle and high degradation. The grid of 5 versus 5 m is adequate to quantify, describe and map of spatial variability of agronomic properties and the content of pasture grass MOS level of degradation with low and high. The MOS content in all levels of degradation of pasture was defined spatial variability thus allowing its mapping. Already in the area with the average level of degradation of the grid 5 × 5 m is ineffective for to quantify, describe and map the spatial variability of variables MSC and MST because of low coefficients of determination and large sums of squared residuals and the absence of spatial dependence for MSMM.

Silva S.B.,Instituto Federal Do Tocantins IFTO | De Oliveira M.A.G.,University of Brasilia | Severino M.M.,University of Brasilia
IEEE Latin America Transactions | Year: 2011

In the National Park of Araguaia, Tocantins-Brazil was installed a pilot project that combines photovoltaic (PV), fuel cells and batteries. The purpose of this pilot project is to demonstrate the viability to produce hydrogen from the PV system in off-peak load and store it to provide power on-demand using the local source, thus ensuring a continuous power flow. In this paper, a methodology to design of PV, batteries, electrolyzers and fuel cells analytically is proposed. The optimization of the hybrid system with aid of computational program HOMER© (Hybrid Optimization Model for Electric Renewable) is presented. Different combinations of sizes were selected in order to identify the optimal combination of the hydrogen based system. A comparison and simulation with differs type of load profile is showing. The results showed reducing cost of hybrid system with demand-side management. © 2011 IEEE.

Pedroza M.M.,Federal University of Rio Grande do Norte | Sousa J.F.,Federal University of Rio Grande do Norte | Vieira G.E.G.,Instituto Federal Do Tocantins IFTO | Bezerra M.B.D.,Federal University of Rio Grande do Norte
Journal of Analytical and Applied Pyrolysis | Year: 2014

The objectives of this study were to produce and characterize bio-fuels through the thermal treatment of sewage sludge in an 1 kg/h rotating cylinder reactor. The experimental procedure was divided into three parts: (a) initial test using the temperatures of 450, 500, 550, 600 and 650 C while the nitrogen flow, the centrifuge rotation and biomass flow were kept constant, (b) 2 4-1 fractional experimental design and (c) experiments exclusively for the characterization of gaseous fraction, using the temperatures of 500, 550 and 600 C. The maximum liquid yield was 10.5% obtained at the temperature of 500 C, inert gas of 200 mL/min, biomass flow of 22 g/min and centrifuge rotation of 20 Hz. The maximum char yield was 61.9%, obtained at 500 C, inert gas of 100 mL/min, biomass flow of 4 g/min and centrifuge rotation frequency of 20 Hz. The highest phase gas yield was 23.3%, obtained at 600 C, inert flow rate of 200 mL/min, biomass flow rate of 22 g/min and rotation frequency of 30 Hz. The bio-oil had the following characteristics: pH between 6.80 and 6.84, density between 1.05 g/mL and 1.09 g/mL, viscosity between 2.5 cSt and 3.1 cSt and high heating value between 16.91 MJ/kg and 17.85 MJ/kg. Non-oxygenated aliphatic (55%) and aliphatic oxygenated hydrocarbons (27%) were found in the bio-oil. The main components detected in the gas phase were H2, CO, CO 2 and CH4. Hydrogen was the main constituent, with a yield of 46.2% at 600 C. Among the hydrocarbons formed, methane was predominant (16.6%) at 500 C. The results show that increasing the temperature from 500 to 600 C favors the increase in the gaseous phase and reduction of solid and liquid fractions. © 2013 Elsevier B.V. All rights reserved.

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