Assessment of the influence of electric arc furnace slag as a non-conventional filler for Nitrile Butadiene Rubber

Reinforcement of polymers by the addition of particles filler is a complex phenomenon that depends mainly on the hydrodynamic effect and a complex interplay between polymer, filler, and interfacial region. Mineral fillers are usually adopted as low-cost extenders due to their lower cost. In this study, the influence of a waste material such as electric arc furnace steel slag is assessed as filler for Nitrile-Butadiene Rubber following experimental procedures and analytical calculations adopted for traditional fillers. It was found that the slag content affects the static and the dynamic properties by increasing the material's capability to storage and dissipate energy. In addition to an important contribution of the hydrodynamic effect, the presence of an increasing immobilized rubber fraction around the slag particles (quantified by a differential scanning calorimetry analysis) plays a central role. The slag stiffens the NBR composite; the increase of static tensile and dynamic shear storage moduli was found to be consistent with the Halpin-Tsai and Guth-Gold prevision models respectively. Moreover, the non-linear dynamic behavior was found to be well-fitted by the Kraus equation models. The reinforcing ability of the slag particles as filler was confirmed by the negative slope of the Kraus plot on swelling data

Estimativas mensais da formação bruta de capital fixo pública no Brasil (2002-2010)

This article presents new monthly estimates of the gross fixed capital formation of the Brazilian general government for the 2002-2010 years. A significant research effort was made to carry out the estimations. First, the many differences between the concepts of "public investment" (as used in the Brazilian public accounting manuals) and "gross fixed capital formation of the general government" (as used in the United Nations System of National Accounts) were carefully identified, and so were the peculiarities of the Brazilian budget process that distort official estimates of the annual gross fixed capital formation of the Brazilian general government and affect the precision of naive estimates of the same variable in higher frequencies. Second, several procedures were developed to correct or mitigate these problems. Finally, additional information was obtained from 20 out of 26 Brazilian states, the federal district, and tens of (large) municipalities in order to allow us to circumvent the relative scarcity of information on the finances of Brazilian state and local governments.Este artigo apresenta estimativas inéditas de séries mensais da formação bruta de capital fixo (FBCF) das administrações públicas no Brasil de 2002 a 2010. A estimação exigiu um esforço significativo de pesquisa. Em primeiro lugar, realizou-se uma análise criteriosa dos conceitos da contabilidade pública e da contabilidade nacional, enfatizando-se as peculiaridades do processo orçamentário brasileiro que enviesam as estimativas anuais dos investimentos públicos divulgadas nas estatísticas oficiais e que afetam a precisão das informações de alta frequência. Em segundo lugar, desenvolveram-se procedimentos para mitigar estes problemas. Por fim, buscou-se contornar a escassez de informações dos governos subnacionais solicitando-se informações adicionais de centenas de contadores públicos, técnicos ou secretários de Fazenda/Planejamento de todos os estados da Federação, do Distrito Federal (DF) e dos maiores municípios