Camila Silva Franco

Distribuição de probabilidades para precipitação máxima diária na Bacia Hidrográfica do Rio Verde, Minas Gerais

Estimativas probabilisticas de eventos extremos sao de grande relevância para o planejamento das atividades humanas. As distribuicoes de probabilidade possibilitam a estimativa de eventos de precipitacao maxima diaria anual associados as suas frequencias de ocorrencia. Objetivou-se, com este trabalho, identificar, dentre as distribuicoes Gumbel, Gama a 2 parâmetros e Generalizada de Valores Extremos (GEV), qual a mais indicada para aplicacao as series historicas de precipitacao maxima diaria anual na bacia hidrografica do rio Verde, no Sul de Minas Gerais. Os parâmetros de cada distribuicao foram estimados pelos metodos dos momentos, maxima verossimilhanca e momentos-L. Para tal, foram empregadas, neste estudo, oito estacoes pluviometricas com series historicas de, no minimo, 20 anos de dados, distribuidas pela bacia hidrografica. Pelos testes de adequacao de Kolmogorov-Smirnov, Qui-Quadrado, Anderson Darling e Filliben, a distribuicao Gumbel, estimada pelos tres metodos, obteve os ajustes menos adequados. A distribuicao GEV, pelo metodo dos momentos-L, foi a mais adequada para analise probabilistica de precipitacao maxima diaria na Bacia Hidrografica do Rio Verde, devendo ser priorizada para planejamentos na regiao.

Performance of the probability distribution models applied to heavy rainfall daily events

Probabilistic studies of hydrological variables, such as heavy rainfall daily events, constitute an important tool to support the planning and management of water resources, especially for the design of hydraulic structures and erosive rainfall potential. In this context, we aimed to analyze the performance of three probability distribution models (GEV, Gumbel and Gamma two parameter), whose parameters were adjusted by the Moments Method (MM), Maximum Likelihood (ML) and L - Moments (LM). These models were adjusted to the frequencies from long-term of maximum daily rainfall of 8 rain gauges located in Minas Gerais state. To indicate and discuss the performance of the probability distribution models, it was applied, firstly, the non-parametric Filliben test, and in addition, when differences were unidentified, Anderson-Darlling and Chi-Squared tests were also applied. The Gumbel probability distribution model showed a better adjustment for 87.5% of the cases. Among the assessed probability distribution models, GEV fitted by LM method has been adequate for all studied rain gauges and can be recommended. Considering the number of adequate cases, MM and LM methods had better performance than ML method, presenting, respectively, 83% and 79.2% of adequate cases.

Mobility of heavy metals in soils of arrangement municipal solid waste

The hydrodispersive knowledge of soil in movement of heavy metals is fundamentally important to prevent and remediate environmental damages. Therefore, studies should be developed on interactions that occur in soils and contaminants solutions. Considering such information in literature, the study of this work is the mobility of Cd, Cu, Pb and Zn metals in three areas of municipal solid waste. The concentrations of ions in the effluent were analyzed using the miscible displacement methodology. Among these evaluated soils, PA presented the lowest potential in relation to leaching of trace elements evaluated. L soil has the highest vulnerability in terms of potential for groundwater contaminations, which requires a greater control in disposal of solid waste containing easily solubilized trace elements.

Comparison of polymers and ceramics in new and discarded electrical insulators: reuse and recycling possibilities

The expansion and maintenance of electricity distribution networks generates large amounts of waste, much of it in the form of discarded insulators that are not reused or recycled. This paper describes the results of tests on used and new ceramic and polymeric insulators to verify if their exposure to weathering justifies their replacement. In new and used ceramic insulators, properties such as contact angle, relative density, porosimetry, dilatometry and X-ray diffraction patterns showed no differences or the differences that were found could not be related to their use. The discarded ceramic material showed high thermal stability, an interesting characteristic for application as chamotte. It can also be reused to replace gravel used in substations. In polymeric insulators, thermogravimetry, differential scanning calorimetry and relative density test results suggest degradation of used material compared to new. This would justify their replacement and discard as waste, but they show little recycling potential.