Catalytic partial oxidation (CPO) of logistic fuels is a promising technology for the small-scale and on-board production of syngas (H2 and CO). Rh coated monoliths can be used as catalysts that, due to Rh high activity, allow the use of reduced reactor volumes (with contact time in the order of milliseconds) and the achievement of high syngas yield. As the CPO process is globally exothermic, it can be operated in adiabatic reactors. The reaction mechanism of the CPO process involves the superposition of exothermic and endothermic reactions at the catalyst inlet. Thus, a hot spot temperature is formed, which may lead to catalyst deactivation via sintering. In this work, the effect of the flow rate on the overall performance of a CPO-reformer has been studied, using iso-octane as model fuel. The focus has been on thermal behavior. The experimental investigation consisted of iC8-CPO tests at varying total flow rates from 5 to 15 NL/min, wherein axially resolved temperature and composition measurements were performed. The increase of flow rate resulted in a progressive increase of the hot spot temperature, with partial loss of activity in the entry zone of the monolith (as evidenced by repeated reference tests of CH4-CPO); conversely, the adiabatic character of the reformer improved. A detailed modelling analysis provided the means for the interpretation of the observed results. The temperature hot spot can be limited by acting on the operating conditions of the process. However, a tradeoff is required between the stability of the catalyst and the achievement of high performances (syngas yield, reactants conversion, and reactor adiabaticity).
ResumoEste trabalho propõe o estudo da função quadrática complexa baseado em gráficos de duas e três dimensões, e, na sua analogia com o gráfico da função quadrática real, a parábola. Nesta abordagem são investigados os tipos de cônicas que surgem no caso da imagem de uma reta por esta função e ao se fazer a intersecção dos gráficos das partes real e imaginária com planos. Esta exploração pode enriquecer o estudo introdutório de funções complexas a nível de graduação.
Palavras-chave: números complexos; função quadrática; cônicasAbstract This paper proposes the study of the complex quadratic function based on two and three dimensional graphs and their analogy with the real quadratic graph, the parabola. In this approach we investigate the types of conics arising in the case of the image of a line by this function and considering the intersection of the real and imaginary parts graphics with planes. This exploration can enrich the introductory study of complex functions at undergraduate level.
Neste artigo apresentamos uma discussão acerca do fetichismo do capital intelectual, aoanalisar a ideologia do conhecimento e a exigência de adaptação do trabalhador no contextoda reestruturação do capital nas últimas décadas. Para tanto, analisamos a emergência dessaideologia – através dos conceitos de sociedade do conhecimento, sociedade da informação,capital intelectual, entre outros – em alguns autores da área de gestão de recursos humanos, nasequência apresenta a crítica desse ideário a partir da análise de alguns autores do pensamentosocial crítico. Finalmente nos posicionamos no sentido de afirmar que se trata de uma novaversão do fetichismo na era da mundialização do capital.
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