Corrosion of brass in a natural and artificial seawater under anaerobic conditions

The corrosion of brass in deoxygenated nonbuffered and buffered artificial and natural seawater was studied. The weight gains and the average corrosion rates of brass samples, immersed in both media during periods of 1 week, 1 and 3 months, were determined. The morphology of the corroded surfaces, with and without the corrosion products, was analyzed by visual observation and scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) was used for the identification of the corrosion products and X-ray diffraction (XRD) for the identification of the crystalline corrosion products. In general it was concluded that deoxygenating and buffering, at pH 9, both contribute to enhance the corrosion of brass in seawate

Crescimento De Cana-de-açúcar Sob Aplicação De Biofertilizante Da Bovinocultura E Ureia

Effluents from intensive cattle breeding and treated with anaerobic reactors are highly relevant for agricultural reuse. Current paper assesses the growth of sugarcane cultivars SP 803280 and RB 867515 for 220 days. Doses 0, 16, 48, 64, 80 and 96 kg ha-1 N were applied derived from biofertilizing sources produced by cattle-breeding waste water and urea. Experimental design comprised randomized blocks with 96 splits and four replications. The cultivars fertilized with biofertilizers caused growth similar to those fertilized with urea. Doses 64, 80 and 96 kg ha-1 had the best efficiency in growth. Since average height of 3 m was obtained for cultures at the end of the experiment, urea may be replaced by biofertilizers.9497398

Avaliação de fluxos de calor e evapotranspiração pelo modelo SEBAL com uso de dados do sensor ASTER

O objetivo deste trabalho foi avaliar a eficiência da aplicação do modelo SEBAL em estimar os fluxos de energia em superfície e a evapotranspiração diária, numa extensa área de cultivo de arroz irrigado, no município de Paraíso do Sul, RS, tendo como parâmetros dados do sensor ASTER. As variáveis estudadas constituem importantes parâmetros do tempo e do clima em estudos agrometeorológicos e de racionalização no uso da água. As metodologias convencionais de estimativa desses parâmetros são pontuais e geralmente apresentam incertezas, que aumentam quando o interesse é o comportamento espacial desses parâmetros. Aplicou-se o algoritmo “Surface Energy Balance Algorithm for Land” (SEBAL), em uma imagem do sensor “Advanced Spaceborne Thermal Emission and Reflection Radiometer” (ASTER). As estimativas obtidas foram comparadas com medições em campo, realizadas por uma estação micrometeorológica localizada no interior da área de estudo. As estimativas mais precisas foram as de fluxo de calor sensível e de evapotranspiração diária, e a estimativa que apresentou maior erro foi a do fluxo de calor no solo. A metodologia empregada foi capaz de reproduzir os fluxos de energia em superfície de maneira satisfatória para estudos agrometeorológicos e de rendimento de culturas.The objective of this study was to evaluate the efficiency of SEBAL model in estimating soil surface energy fluxes and daily evapotranspiration for a large area of irrigated rice farms, near the municipality of Paraíso do Sul, RS, Brazil, using data from ASTER sensor. The evaluated variables are important weather and climatic parameters for agrometeorological studies and rationalization of water use. The conventional methodologies for estimating these parameters generally present uncertainties, which increase when concern is in the spatial behavior of such parameters. The Surface Energy Balance Algorithm for Land (SEBAL) was applied in an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scene and the estimates were compared to micrometeorological data retrieved from a station located in the studied area. The most accurate modeled parameter estimatives were sensitive heat and evapotranspiration, and the one which presented the highest error was soil heat flux. The adopted methodology was able to reproduce surface energy fluxes for agrometeorological and crop yield studies