ABSTRACT During the production of petroleum and gas, the equipments employed for this activity are subjected to synergetic wear mechanisms, such as corrosion, corrosion-cavitation and corrosion-cavitation-erosion. Laboratory experiments has been performed to reproduce some of these mechanisms, however, sometimes the tests is not capable to recreate the complexities caused by hydrodynamic flows, physico-chemical and mechanical non-linearities. The main objective of this work is to evaluate specimens of low carbon steel under laboratory conditions, such as corrosive, cavitative-corrosive (CO2) and corrosive-erosive (CO2 + SiO2) environments. During the tests, the specimens were subjected to a stirring aqueous saline solution (0 and 5.0 m/s) at two levels of temperature, with gas injection (5.0 L/min) and contaminated with by solids particles of SiO2 (2.5% mass). The surface of the specimens subjected to upstream flow (0° in a cylindrical generatrix of the specimen), and downstream flows (180º) were analyzed by profilometry. The measurements of roughness and waviness of all specimens were statistically analyzed at a confidence level of 95% and significant differences observed in some matrices were discussed. The results suggest that the wear mechanisms that act in the upstream generatrix differ from that of specimen downstream.

As décadas que se seguiram à Segunda Guerra Mundial foram dominadas pelo domínio do automóvel na mobilidade urbana, tanto no que se refere à sua crescente importância na repartição modal, como na definição das políticas públicas e estratégias de acessibilidade. Com a primeira crise dos preços do petróleo, nos anos 1970, e a posterior consciência ambiental dos impactos negativos atribuídos ao setor dos transportes, começaram a desenhar-se outros tipos de políticas, mais orientadas pelos conceitos de intermodalidade e de coesão social, além de mais preocupadas em reduzir os impactos ambientais da mobilidade urbana. Num período em que os novos países emergentes atravessam uma fase de forte crescimento econômico e consequente aumento da motorização individual, será útil analisar essa evolução das políticas de mobilidade e retirar algumas conclusões quanto aos caminhos a prosseguir, pondo em evidência as especificidades que existem nesses países, mas também o que podem aproveitar dos ensinamentos do passado recente.

The decades following the Second World War were characterized by the predominant presence of the automobile in urban mobilit y, both in terms of its increasing importance in the modal split, and also regarding the definition of public policies and strategies of accessibility. With the first oil crisis in the 1970s and the subsequent environmental awareness of the negative impacts of the transport sector, new policies began to be designed, guided by concept s such as intermodality and social cohesion, as well as more concerned about reducing the environment al impacts of urban mobility. In a period where the new emerging countries present a strong economic growth and a consequent increase in the motorization rate of their population, it is useful to analyze the evolution of such mobility policies and share some conclusions about the paths to follow, highlighting the specificities of those countries, and also the lessons of the recent past.