Food additives are chemical substances added to improve organoleptic characteristics, in this context, there are several synthetic dyes, such as sunset yellow, tartrazine, erioglaucine, allura red, indigo carmine, and new coccine, that can also be identified through different analytical techniques such as infrared spectroscopy, UV-Vis spectrophotometry, high performance liquid chromatography with diode array detector and mass spectrometry. Therefore, the objective of this work was to compare methods developed for different analytical techniques, in order to identify the one that presents greater efficiency in certain applications. For this, the patterns of the dyes were analyzed, as well as their mixtures and foods that had them. As a result, the CLAE-DAD presents excellent selectivity and linearity of the calibration curves, but it presents higher LD and LQ values when compared to the UV-Vis, in turn the infrared provides information regarding functional groups and bonds. Mass spectrometry showed great capabilities in identifying the molecular formula and better selectivity in the absence of the erioglaucine dye. It is not feasible to indicate the best or worst analytical approach, but it is possible to point out which one is more suitable for each application. Regarding the quantification capacity, chromatography and UV-Vis are good alternatives, but in mixtures containing more than one dye, CLAE-DAD is more suitable due to the better selectivity. Regarding the identification capacity, mass spectrometry, especially FT-ICR MS, is the most appropriate technique to propose molecular formulas due to its high resolution and mass accuracy. The advantage of FTIR was the easier sample preparation, being able to analyze the dyes in the solid state.

Resumo Este trabalho de pesquisa tem como objetivo investigar o comportamento estrutural dinâmico e avaliar o conforto humano de passarelas, quando submetidas à caminhada de pedestres, com base em testes experimentais e calibrações dos modelos em elementos finitos. Assim sendo, a estrutura investigada corresponde a uma passarela de pedestres real, com vão de 24,4 m, localizada no campus da Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brasil. Inicialmente, os ensaios para obtenção dos parâmetros modais foram realizados utilizando-se duas estratégias para aquisição dos dados. Em seguida, foram realizados testes experimentais de vibração forçada sobre a passarela, considerando os pedestres caminhando com diferentes frequências de passo. Na sequência do estudo, um modelo de elementos finitos foi desenvolvido com base no uso do programa computacional ANSYS. Os testes experimentais da passarela foram utilizados para a calibração dos resultados no modelo numérico. Finalmente, foi realizada uma avaliação do conforto humano, com base nas comparações entre os resultados (acelerações de pico), da monitoração experimental dinâmica e das recomendações fornecidas pelos guias de projeto SÉTRA, HIVOSS e AISC.

Abstract This research work aims to investigate the dynamic structural behaviour and assess the human comfort of footbridges, when subjected to pedestrian walking, based on experimental tests and tuning of finite element model. Therefore, the investigated structure is associated to a real pedestrian footbridge, spanning 24.4m, located at the campus of the State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil. Initially, an experimental modal testing was conducted using two data acquisition strategies. After that the experimental forced vibration tests were performed on the footbridge, considering the pedestrians walking with different step frequencies. In sequence of the study, a finite element model was developed based on the ANSYS computational program. The experimental footbridge tests were used for the calibration of results on the numerical model. Finally, a human comfort assessment was performed, based on the comparisons between the results (peak accelerations), of the dynamic experimental monitoring and the recommendations provided by design guides SÉTRA, HIVOSS and AISC.