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The superficial characteristics of honed surfaces are relevant for the tribological performance of cylinders of internal combustion engines (MCI). Recent studies found a correlation between the occurrence of the phenomenon called folded metal and the presence of graphite of cast irons. However, the honing process tends to overlap the graphite, such that an application of a technique to remove a thin layer of material, exposing the graphite, would be useful. This paper aims to determine the best condition, of electric potential and time, for the exposition of graphite in honed surfaces using a technique of electrolyte polishing. The polishing was made on the concave surface with aid of a polishing mask developed for this matter. Samples of honed cylinders were removed from MCI manufactured using a compacted graphite iron. The characterizations were done through metallography and white light interferometry. To determine the ideal condition, several conditions of polishing were tested. For the verification of the repeatability, five repetitions were performed with the best condition. The results showed satisfactory repeatability, with an exposition of graphite and the matrix etching. The roughness of the polished region presented considerable uniformity, with a significant change of roughness in comparison to the honed surface. Furthermore, removal of the characteristic topography of the honed surface was observed. The layer removed showed little variation in depth along the polished region, with values close to 5 µm. This value accomplishes the demand of layer removal for the exposition of subsurface graphite.

A crescente preocupação em relação às emissões antropogênicas e seu impacto na qualidade do ar trouxe uma discussão mais aprofundada sobre os poluentes de formação secundária, principalmente o ozônio troposférico. Esta molécula se origina de reações fotoquímicas com radiação ultravioleta e os produtos da queima de combustíveis fósseis, como os óxidos de nitrogênio (NO x ) e os compostos orgânicos voláteis (COV). Assim como o dióxido de carbono (CO 2 ) levanta discussões há décadas a respeito do aumento do efeito estufa, o ozônio (O 3 ) também demanda atenção, principalmente quanto ao meio ambiente e patologias humanas. Estudos anteriores já mostraram forte correlação entre a concentração de ozônio em grandes centros urbanos e a incidência de complicações cardiorrespiratórias e neurológicas. O presente artigo traça um panorama da atual situação dos estudos relacionados à formação do ozônio troposférico como poluente secundário proveniente das emissões veiculares. Apresenta-se uma revisão da literatura dos principais artigos que tratam do assunto no âmbito nacional e internacional, apresentando ao leitor os fundamentos do estado da arte sobre o assunto. ABSTRACT.The increasing concern about anthropogenic emission and its impact on air quality brings a deep discussion about secondary pollutants formation, mainly related to tropospheric ozone. The origin of this molecule is the photochemical reactions between products of burning fossil fuel, such as nitrogen oxides (NO x ) and volatile organic compounds (VOC), in the presence of ultraviolet radiation. Like carbon dioxide (CO 2 ) raises discussions for decades about the growing greenhouse effect, ozone also requires attention, mainly related to the environment and human pathologies. Previous studies have already shown strong correlations between ozone concentration in large urban centers and the incidence of cardiorespiratory and neurological complications. The present paper develops an overall picture of the current studies' situation associated to tropospheric ozone formation as a secondary pollutant produced from vehicular emissions. A literature review is presented, regarding the main articles related to the subject in both national and international scenario, presenting to the reader the state of the art fundamentals.

The increasing applications of poly-ether-ether-ketone (PEEK) in the industry makes this polymer appealing for the development of a new industry focused on its production. PEEK displays remarkable mechanical properties that are not commonly found in polymeric materials, and its biocompatibility becomes attractive for the manufacture of prosthesis, stents and many other medical apparatuses. In addition, the new technique of Additive Manufacturing (AM) enables the printing of highly complex geometries with low weight, aiming the automotive and aeronautic industries as well. Despite not being relatively new, there are not many enterprises producing PEEK in the world, especially in the South American market. This raises a question regarding the size of the PEEK market in this region and the expected demand for the upcoming years. Therefore, this paper aims to analyze and predict the demand of PEEK for the Mercosur and Brazil markets, verifying the feasibility of the creation of a specialized industry in the region.

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