In the past decades, a great variety of model fitting and model free (isoconversional) methods have been developed for extracting kinetic parameters for solid state reactions from thermally stimulated experimental data (TGA, DSC, DTA etc.). However, these methods have met with significant controversies about their methodologies. Firstly, model-fitting methods have been strongly criticized because almost any reaction mechanism can be used to fit the experimental data satisfactorily with drastic variations of the kinetic parameters, and no good criterion exists to tell which mechanism is the best choice. Secondly, previous model free methods originated from the isoconversional principle, which is often called the basic assumption; previous studies comparing the accuracy of model free methods have not paid attention to the influence of the principle on model free methods and, therefore, their conclusions are problematic. This work gives, firstly, a critical study of previous methods for evaluating kinetic parameters of solid state reactions and a critical analysis of the isoconversional principle of model free methods. Then an analysis is given of the invariant kinetic parameters method and recommends an incremental version of it. Based on the incremental method and model free method, a comprehensive method is proposed that predicts the degree of the dependences of activation energy on heating programs, and obtains reliable kinetic parameters. In addition, this work also compares the accuracy of previous methods and gives recommendations to apply them to kinetic studies.

Made available in DSpace on 2017-07-21T13:42:52Z (GMT). No. of bitstreams: 1 Alexsandro Teixeira Ribeiro.pdf: 16662937 bytes, checksum: 126f1dc06071af04795937b6bfff4aa7 (MD5) Previous issue date: 2016-02-22 / More than century-old union press plays a fundamental role in the history of class struggles as an instrument of defense of the ideals and causes of workers in Brazil. In order to discuss the journalism practiced in the union press, the present work, master's research fruit in journalism conducted at the Graduate Program in Journalism at the State University of Ponta Grossa (UEPG), is the result of analysis that sought to identify characteristics contemporary journalism union, based on publications six unions representing workers in Parana. This work was developed under theoretical basis for Otto Groth (2011), which recognizes journalism as human cultural production, and under the guidance of comprehensive method of Weberian inspiration, understanding of journalism. Contemporary journalism union, based on the analyzed trade union publications, this research points as a mark of union press the role of their own labor union in the themes addressed and the union board as the predominant speech in the newspapers. / Mais que centenária, a imprensa sindical desempenha um papel fundamental na história de lutas de classes como instrumento de defesa dos ideais e das causas dos trabalhadores no Brasil. Com o objetivo de debater o jornalismo praticado na imprensa sindical, o presente trabalho, fruto de pesquisa de mestrado em jornalismo realizada junto ao Programa de Pós Graduação em Jornalismo da Universidade Estadual de Ponta Grossa (UEPG), é resultado de análise que buscou identificar características do jornalismo sindical contemporâneo, com base em publicações de seis entidades sindicais de representação dos trabalhadores no Paraná. A presente dissertação foi desenvolvida sob base teórica de Otto Groth (2011), que reconhece o jornalismo como produção cultural humana, e sob orientação do método compreensivo, de inspiração weberiana, para compreensão do jornalismo. Do jornalismo sindical contemporâneo, com base nas publicações sindicais analisadas, esta pesquisa aponta como marca da imprensa sindical o protagonismo da própria entidade sindical nas temáticas abordadas e da diretoria do sindicato como fala predominante nos jornais.