RESUMO
Energetic characterization of biomass allows for assessing its energy potential for application in different conversion processes into energy. The objective of this study is to physicochemically characterize pineapple crown leaves (PC) for their application in energy conversion processes. PC was characterized according to ASTM E871-82, E1755-01, and E873-82 for determination of moisture, ash, and volatile matter, respectively; the fixed carbon was calculated by difference. Higher heating value was determined by ASTM E711-87 and ash chemical composition was determined by XRF. The thermogravimetric and FTIR analyses were performed to evaluate the thermal decomposition and identify the main functional groups of biomass. PC has potential for application in thermochemical processes, showing high volatile matter (89.5%), bulk density (420.8 kg/m(3)), and higher heating value (18.9 MJ/kg). The results show its energy potential justifying application of this agricultural waste into energy conversion processes, implementing sustainability in the production, and reducing the environmental liabilities caused by its disposal.
Assuntos
Ananas/química , Biomassa , Energia Renovável , Agricultura , Carbono/análise , Folhas de Planta/químicaRESUMO
The synchrotron radiation total reflection X-ray fluorescence (SRTXRF) technique was used for the analysis of heavy metals in produced water samples from oil field in Rio Grande do Norte, in order to determine potential sources of pollution. Since the inorganic components in produced water generally resembling sea water, pre-concentration procedures have been applied to increase the concentration of the analyte of interest and to minimize the salt matrix effects. This technique allows us to determine the contents of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Hg and Pb in 20 produced water samples. The great majority of the sampling points presented low elemental concentration value. However, in some sample, the Fe, Ni, Cu, Zn and Hg concentration were higher than the established limits by the Brazilian legislation.
Assuntos
Metais Pesados/análise , Espectrometria por Raios X/métodos , Água/química , Fluorescência , Síncrotrons , Poluição da Água/análiseRESUMO
Este trabalho apresenta os fundamentos do método de cálculo da SpO2 e discute dois diferentes algoritmos. As vantagens e desvantagens de cada uma deles são ressaltadas. Através de alguns resultados comprova-se que a eliminação do componente DC do sinal não afeta o cálculo da SpO2 e simplifica o tratamento analógico, proporcionando uma maior confiabilidade ao sistema.