Instituto Superior Técnico

About: Instituto Superior Técnico is a based out in . It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 10085 authors who have published 30226 publications receiving 667524 citations. The organization is also known as: IST & Instituto Superior Tecnico.

Reliability of Maintained Ship Hulls Subjected to Corrosion

Abstract: A time-variant formulation is presented to model the degrading effect that corrosion has on the reliability of ship hulls. The effect of corrosion is represented as a time dependent decrease of plate thickness that affects the midship section modulus. One repair policy was considered and the example results showed the effect of plate replacement when its thickness reached 75% of the original thickness. The example results also illustrated how the limit value of the thickness in the repair criteria influences the reliability and the decision about repair actions. This is also shown for the effect of different corrosion rates and allowable stresses.

Effect of fly ash on concrete reinforcement corrosion studied by eis

Abstract: The corrosion process of steel embedded in concrete with various amounts of fly ash (up to 50% of the total binder) was tested under complete and partial immersion, in sodium chloride solution. The corrosion process was followed by monitoring of open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Fly ash addition has led to a raise of concrete resistivity and of the time for corrosion initiation and to a decrease of corrosion rate.

RenewIslands methodology for sustainable energy and resource planning for islands

Abstract: With respect to energy supply, most of the islands depend on importation, mainly from oil and its related products, and others are dependant on weak electricity grid connexions with mainland. Scarce resources are used inefficiently, supplying end-use energy and other life-supporting commodities, like power, heat, cold, transport fuel, water, waste treatment and waste water treatment. It is possible to integrate various flows and decrease the energy intensity, although the task is situation dependant and involves a large number of different systems. RenewIslands methodology for the assessment of alternative scenarios for energy and resource planning is presented here, and applied to several islands. The methodology helps in choosing energy and resource flows integration, based on the island needs, its resources, and the applicable technologies.

Stimulated Raman and Brillouin Backscattering of Collimated Beams Carrying Orbital Angular Momentum

Abstract: We study theoretically the exchange of angular momentum between electromagnetic and electrostatic waves in a plasma, due to the stimulated Raman and Brillouin backscattering processes. Angular momentum states for plasmon and phonon fields are introduced for the first time. We demonstrate that these states can be excited by nonlinear wave mixing, associated with the scattering processes. This could be relevant for plasma diagnostics, both in laboratory and in space. Nonlinearly coupled paraxial equations and instability growth rates are derived.