Júlio de Castilhos, Brazil
Júlio de Castilhos, Brazil

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ten Caten A.,Instituto Federal Farroupilha IFF | Dalmolin R.S.D.,Federal University of Santa Maria | Pedron F.A.,Federal University of Santa Maria
Ciencia Rural | Year: 2011

Available technologies for Earth observation offer a wide range of predictors relevant to Digital Soil Mapping (DSM). However, models with a large number of predictors, as well as, the existence of multicollinearity among the data, may be ineffective in the mapping of classes and soil properties. The aim of this study was to use the Principal Component Analysis (PCA) to reduce the number of predictors in the multinomial logistic regression (MLR) used in soil mapping. Nine environmental covariates, related to the relief factor of soil formation, were derived from a digital elevation model and named the original variables, which were submitted to PCA and transformed into principal components (PC). The MLR were developed using the terrain attributes and the PC as explanatory variables. The soil map generated from three PC (65.6% of the original variance) had a kappa index of 37.3%, lower than the 48.5% achieved by the soil map generated from all nine original variables.

de Pellegrini L.G.,Instituto Federal Farroupilha IFF | Monteiro A.L.G.,Federal University of Paraná | Neumann M.,State University of the Central West | de Moraes A.,Federal University of Paraná | And 3 more authors.
Ciencia Rural | Year: 2010

It was evaluated the effect of nitrogen fertilization in ryegrass pasture (Lolium multiflorum Lam.) on the production of meat lamb under continuous grazing. Ryegrass pasture was established under no-tillage cropping in area of animal-crop integration system. The fertilization was held with 60kg of P2O5 ha-1 and 60kg of K2O ha-1. The treatments corresponded to the doses 0; 75; 150 e 225kg of N ha-1, in the urea form (45% de N) in single application, 35 days after seeding. The evaluation period was of 84 days. The forage was influenced quadratic ally by N rates, with minimum point at 182.75kg of N ha-1. However, the supply of leaf blades (LFM) was not influenced by doses of N (3.8kg LFM 100kg-1 live weight) or by the average daily weight gain, averaging 0.133 kg of LW an day. For stocking rate and live weight gain per area the doses of N increased 3.0 kg of LW-1 ha-1 and 1.1kg of LW ha-1, respectively for each kg of N applied. Nitrogen fertilization provides increases in animal productivity which results in increase kg of meat produced in this system.

Brandalise M.,Instituto Federal Farroupilha IFF | Tusi M.M.,URI Integrated Regional University Brazil | Spinace E.V.,Brazilian Nuclear Energy Research Institute (IPEN) | Oliveira Neto A.,Brazilian Nuclear Energy Research Institute (IPEN)
Materials Science Forum | Year: 2016

Pd/C, Au/C, AuBi/C, PdAu/C, PdAuBi/C electrocatalysts (with different atomic ratios and 20 wt% of metal loading) were prepared by borohydride reduction method using a water/2- propanol mixture as solvent, Pd(NO3)2.2H2O, HAuCl4.3H2O and Bi(NO3)3.5H2O as metal sources, carbon black Vulcan XC72 as support and NaBH4 as reducing agent. The activities of the prepared electrocatalysts for methanol and ethanol electro-oxidation in alkaline medium were investigated by chronoamperometry using the thin porous coating technique. Chronoamperometry experiments showed that PdAu/C (Pd:Au atomic ratio of 50:50) has superior activity and stability for methanol and ethanol electro-oxidation compared with other catalysts. © 2016 Trans Tech Publications, Switzerland.

Polanco N.S.O.,Brazilian Nuclear Energy Research Institute (IPEN) | Tusi M.M.,URI Integrated Regional University Brazil | Brandalise M.,Instituto Federal Farroupilha IFF | Oliveira Neto A.,Brazilian Nuclear Energy Research Institute (IPEN) | Spinace E.V.,Brazilian Nuclear Energy Research Institute (IPEN)
Materials Science Forum | Year: 2016

A factorial design study was performed to evaluate the influence of the BH4 -:PtRu molar ratio (5 and 15) and the solvent (water or isopropyl alcohol) in the preparation of PtRu/C electrocatalysts for Direct Methanol Fuel Cell (DMFC) anodes. The obtained materials were characterized by Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). For both solvents increasing the BH4 -:PtRu molar ratio from 5 to 15 leads to a decrease of the mean nanoparticle sizes and, using water as solvent, it was observed better distributions of the nanoparticles on the carbon support than using isopropyl alcohol. The DMFC maximum power density was obtained using a electrocatalyst prepared with a BH4 -:PtRu molar ratio of 15 and water as solvent. The analysis of the effect of interaction of the two parameters showed that the variations of the maximum power density was more dependent of the BH4 -:PtRu molar ratio than of the solvent used. © 2016 Trans Tech Publications, Switzerland.

Hinnah F.D.,Federal University of Santa Maria | Heldwein A.B.,Federal University of Santa Maria | Maldaner I.C.,Instituto Federal Farroupilha IFF | Loose L.H.,Federal University of Santa Maria | And 2 more authors.
Bragantia | Year: 2014

This paper explores diferent models of non-destructive leaf area estimates for Solanum melongela L. by the measure of leaf length (C) and blade width (L). The methodology involved eggplant cultivation in the greenhouse from March to June. Plant leaves were sampled at random throughout the growing season, totalizing 186 leaves, of which 98 were used to estimate the model parameters and 88 were used for model validation. The samples covered wide spectrum of leaf dimensions, in order to minimize root mean square error (RMSE). Leaves were sampled at 71, 79, 81, 85, 92 and 99 days afer transplanting. The highest possible numbers of leaf discs were obtained with a 25mm auger. Correlations were computed between the leaf area obtained by the discs method and the linear dimensions of L and C, the product of both (CL) and the square length multiplied by the width (C2L). Regression analyses for 20 models were tested, including quadratic, exponential, linear, logarithmic and power model, of which 12 had a high coefcient of determination (R2) value. The quadratic model (Y = - 5.78+0.4981CL–3.263.10-4CL2) and the power model (Y = 0.4395CL1.0055) showed the best estimates, with R2 of 0.964 for both, and RMSE of 33.2 and 34.4, respectively. With only one leaf dimension the quadratic model (Y = -63.5+10.492L+0.2822L2; R2 = 0.937; RMSE = 44.1) is an alternative, with little impact on the precision. © 2014, Instituto Agronomico. All rights reserved.

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