In the present work, we propose the application of stable isotope analysis (δ13C) as an auxiliary tool for the inspection of sugarcane/petroleum polyethylene blends. Our results are supported from the analysis of selected samples by accelerator mass spectrometry (14C-AMS). From the results, it was concluded that the δ13C method is suitable to discriminate samples derived from sugarcane, petroleum, or its blends. It was also noted that both regression models (δ13C method and the δ13C vs 14C-AMS regression) presents potential to estimate the bio-based content; however, future work should focus on validating these models. From the screening model, developed with δ13C data, 33.33% of the samples were highlighted as suspected of being out of specification. Thus, the screening method can identify samples most likely to be out of specification and reduce the demand for inspection of biogenic content following the ASTM D6866 standard (14C-AMS).

This work performs an exploratory analysis of the sparkling wines from the state of Rio Grande do Sul, Brazil. Samples of traditional sparkling wine and Moscatel sparkling wine were analyzed and chemometrics tools were applied to physicochemical, gas chromatography and stable carbon isotope analysis. The carbon isotope ratio (δ13C-CO2) of the samples presents great heterogeneity and confirm that the isotopic signature of the CO2 could be derived from the fermentation of C4 sugar. The principal component analysis (PCA) was capable to discriminate and classify the samples in their respective groups and combined data approach was especially important to identify the correlation between the studied variables. With the increasing production of sparkling wines in Brazil, this work helps to evaluate the standards of the local sparkling wines.

Uma descrição geral da modelagem numérica da composição química da atmosfera é fornecida neste trabalho. Os papéis relevantes de alguns gases traço e aerossóis no balanço radiativo do planeta, na alteração do ciclo hidrológico e na poluição do ar são discutidos. Partindo da equação da continuidade, integrada no sistema de equações governantes da atmosfera, os diversos termos que constituem a emissão, deposição, reatividade química e transporte (resolvido e sub-grade) são apresentados juntamente com formas de obter a solução numérica. Dentre os componentes desta equação, o termo de reatividade química se destaca pela complexidade do problema em si, na obtenção da solução numérica e no alto custo computacional envolvido. Exemplos são fornecidos utilizando o modelo CCATT-BRAMS com recente inclusão de reatividade química. Em particular, a simulação do ozônio troposférico constitui uma tarefa complexa pela falta de dados de emissões, porém resultados obtidos são compatíveis com outros modelos validados. Simulações numéricas realizadas, para a estação seca de 2002, permitiram estudar possíveis ciclos biogeoquímicos e corredores de formação e deposição de ozônio e aerossóis de queimadas, assim como o papel destes últimos na estabilização termodinâmica e precipitação.

A general description of the numerical modeling of the atmospheric chemical composition is presented. The relevant role played by some trace gases and aerosols on the Earth radiative budget, hydrological cycle and air quality are discussed. The formulation for emission, deposition, chemical reactions and transport (resolved and sub-grid scale) processes are introduced within the mass continuity equation integrated to the basic equations system for the Earth atmosphere. The numerical aspects of this formulation are as well discussed, specially the intrinsic complexity and the high computational costs of the chemical reactions system. Examples are showed using results obtained with the CCATT - BRAMS model, such as the sensitivity of the tropospheric ozone simulation to reliable emission data and comparison of the CCATT-BRAMS results with other model. Numerical simulations performed for the 2002 dry season allowed to study possible biogeochemical cycles and corridors of tropospheric ozone formation, transport and deposition from precursor's emissions by biomass burning activities. We also looked at the atmospheric model response to the direct effect of biomass burning aerosols on the thermodynamic equation and on the convective inhibition.